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Sample records for 3d periodic arrays

  1. Complex modes and effective refractive index in 3D periodic arrays of plasmonic nanospheres.

    PubMed

    Campione, Salvatore; Steshenko, Sergiy; Albani, Matteo; Capolino, Filippo

    2011-12-19

    We characterize the modes with complex wavenumber for both longitudinal and transverse polarization states (with respect to the mode traveling direction) in three dimensional (3D) periodic arrays of plasmonic nanospheres, including metal losses. The Ewald representation of the required dyadic periodic Green's function to represent the field in 3D periodic arrays is derived from the scalar case, which can be analytically continued into the complex wavenumber space. We observe the presence of one longitudinal mode and two transverse modes, one forward and one backward. Despite the presence of two modes for transverse polarization, we notice that the forward one is "dominant" (i.e., it contributes most to the field in the array). Therefore, in case of transverse polarization, we describe the composite material in terms of a homogenized effective refractive index, comparing results from (i) modal analysis, (ii) Maxwell Garnett theory, (iii) Nicolson-Ross-Weir retrieval method from scattering parameters for finite thickness structures (considering different thicknesses, showing consistency of results), and (iv) the fitting of the fields obtained through HFSS simulations. The agreement among the different methods justifies the performed homogenization procedure in case of transverse polarization. PMID:22274192

  2. Electromagnetic coupling and array packing induce exchange of dominance on complex modes in 3D periodic arrays of spheres with large permittivity

    DOE PAGESBeta

    Campione, Salvatore; Capolino, Filippo

    2016-01-25

    In this study, we investigate the effect on wave propagation of array packing and electromagnetic coupling between spheres in a three-dimensional (3D) lattice of microspheres with large permittivity that exhibit strong magnetic polarizability. We report on the complex wavenumber of Bloch waves in the lattice when each sphere is assumed to possess both electric and magnetic dipoles and full electromagnetic coupling is accounted for. While for small material-filling fractions we always determine one dominant mode with low attenuation constant, the same does not happen for large filling fractions, when electromagnetic coupling is included. In the latter case we peculiarly observemore » two dominant modes with low attenuation constant, dominant in different frequency ranges. The filling fraction threshold for which two dominant modes appear varies for different metamaterial constituents, as proven by considering spheres made by either titanium dioxide or lead telluride. As further confirmation of our findings, we retrieve the complex propagation constant of the dominant mode(s) via a field fitting procedure employing two sets of waves (direct and reflected) pertaining to two distinct modes, strengthening the presence of the two distinct dominant modes for increasing filling fractions. However, given that one mode only, with transverse polarization, at any given frequency, is dominant and able to propagate inside the lattice, we are able to accurately treat the metamaterial that is known to exhibit artificial magnetism as a homogeneous material with effective parameters, such as the refractive index. Results clearly show that the account of both electric and magnetic scattering processes in evaluating all electromagnetic intersphere couplings is essential for a proper description of the electromagnetic propagation in lattices.« less

  3. A 3-D microfluidic combinatorial cell array.

    PubMed

    Liu, Mike C; Tai, Yu-Chong

    2011-02-01

    We present the development of a three-dimensional (3-D) combinatorial cell culture array device featured with integrated three-input, eight-output combinatorial mixer and cell culture chambers. The device is designed for cell-based screening of multiple compounds simultaneously on a microfluidic platform. The final assembled device is composed of a porous membrane integrated in between a Parylene 3-D microfluidic chip and a PDMS microfluidic chip. The membrane turned the cell culture chambers into two-level configuration to facilitate cell loading and to maintain cells in a diffusion dominated space during device operation. Experimentally, we first characterized the combined compound concentration profile at each chamber using a fluorescence method. We then successfully demonstrated the functionality of the quantitative cell-based assay by culturing B35 rat neuronal cells on this device and screening the ability of three compounds (1,5-dihydroxyisoquinoline, deferoxamine, and 3-aminobenzoic acid) to attenuate cell death caused by cytotoxic hydrogen peroxide. In another experiment, we assayed for the combinatorial effects of three chemotherapeutic compound exposures (vinorelbine, paclitaxel, and γ-linolenic acid) on human breast cancer cells, MDA-MB-231. The same technology will enable the construction of inexpensive lab-on-a-chip devices with high-input combinatorial mixer for performing high-throughput cell-based assay and highly parallel and combinatorial chemical or biochemical reactions. PMID:21063783

  4. Array servo scanning micro EDM of 3D micro cavities

    NASA Astrophysics Data System (ADS)

    Tong, Hao; Li, Yong; Yi, Futing

    2010-12-01

    Micro electro discharge machining (Micro EDM) is a non-traditional processing technology with the special advantages of low set-up cost and few cutting force in machining any conductive materials regardless of their hardness. As well known, die-sinking EDM is unsuitable for machining the complex 3D micro cavity less than 1mm due to the high-priced fabrication of 3D microelectrode itself and its serous wear during EDM process. In our former study, a servo scanning 3D micro-EDM (3D SSMEDM) method was put forward, and our experiments showed it was available to fabricate complex 3D micro-cavities. In this study, in order to improve machining efficiency and consistency accuracy for array 3D micro-cavities, an array-servo-scanning 3D micro EDM (3D ASSMEDM) method is presented considering the complementary advantages of the 3D SSMEDM and the array micro electrodes with simple cross-section. During 3D ASSMEDM process, the array cavities designed by CAD / CAM system can be batch-manufactured by servo scanning layer by layer using array-rod-like micro tool electrodes, and the axial wear of the array electrodes is compensated in real time by keeping discharge gap. To verify the effectiveness of the 3D ASSMEDM, the array-triangle-micro cavities (side length 630 μm) are batch-manufactured on P-doped silicon by applying the array-micro-electrodes with square-cross-section fabricated by LIGA process. Our exploratory experiment shows that the 3D ASSMEDM provides a feasible approach for the batch-manufacture of 3D array-micro-cavities of conductive materials.

  5. Array servo scanning micro EDM of 3D micro cavities

    NASA Astrophysics Data System (ADS)

    Tong, Hao; Li, Yong; Yi, Futing

    2011-05-01

    Micro electro discharge machining (Micro EDM) is a non-traditional processing technology with the special advantages of low set-up cost and few cutting force in machining any conductive materials regardless of their hardness. As well known, die-sinking EDM is unsuitable for machining the complex 3D micro cavity less than 1mm due to the high-priced fabrication of 3D microelectrode itself and its serous wear during EDM process. In our former study, a servo scanning 3D micro-EDM (3D SSMEDM) method was put forward, and our experiments showed it was available to fabricate complex 3D micro-cavities. In this study, in order to improve machining efficiency and consistency accuracy for array 3D micro-cavities, an array-servo-scanning 3D micro EDM (3D ASSMEDM) method is presented considering the complementary advantages of the 3D SSMEDM and the array micro electrodes with simple cross-section. During 3D ASSMEDM process, the array cavities designed by CAD / CAM system can be batch-manufactured by servo scanning layer by layer using array-rod-like micro tool electrodes, and the axial wear of the array electrodes is compensated in real time by keeping discharge gap. To verify the effectiveness of the 3D ASSMEDM, the array-triangle-micro cavities (side length 630 μm) are batch-manufactured on P-doped silicon by applying the array-micro-electrodes with square-cross-section fabricated by LIGA process. Our exploratory experiment shows that the 3D ASSMEDM provides a feasible approach for the batch-manufacture of 3D array-micro-cavities of conductive materials.

  6. Influence of viscosity on the reflection and transmission of an acoustic wave by a periodic array of screens. The general 3-D problem

    PubMed Central

    Homentcovschi, Dorel; Miles, Ronald N.

    2008-01-01

    An analysis is presented of the diffraction of a pressure wave by a periodic grating including the influence of the air viscosity. The direction of the incoming pressure wave is arbitrary. As opposed to the classical nonviscous case, the problem cannot be reduced to a plane problem having a definite 3-D character. The system of partial differential equations used for solving the problem consists of the compressible Navier-Stokes equations associated with no-slip boundary conditions on solid surfaces. The problem is reduced to a system of two hypersingular integral equations for determining the velocity components in the slits’ plane and a hypersingular integral equation for the normal component of velocity. These equations are solved by using Galerkin’s method with some special trial functions. The results can be applied in designing protective screens for miniature microphones realized in MEMS technology. In this case, the physical dimensions of the device are on the order of the viscous boundary layer so that the viscosity cannot be neglected. The analysis indicates that the openings in the screen should be on the order of 10 microns in order to avoid excessive attenuation of the signal. This paper also provides the variation of the transmission coefficient with frequency in the acoustical domain. PMID:19122753

  7. Computation of optimized arrays for 3-D electrical imaging surveys

    NASA Astrophysics Data System (ADS)

    Loke, M. H.; Wilkinson, P. B.; Uhlemann, S. S.; Chambers, J. E.; Oxby, L. S.

    2014-12-01

    3-D electrical resistivity surveys and inversion models are required to accurately resolve structures in areas with very complex geology where 2-D models might suffer from artefacts. Many 3-D surveys use a grid where the number of electrodes along one direction (x) is much greater than in the perpendicular direction (y). Frequently, due to limitations in the number of independent electrodes in the multi-electrode system, the surveys use a roll-along system with a small number of parallel survey lines aligned along the x-direction. The `Compare R' array optimization method previously used for 2-D surveys is adapted for such 3-D surveys. Offset versions of the inline arrays used in 2-D surveys are included in the number of possible arrays (the comprehensive data set) to improve the sensitivity to structures in between the lines. The array geometric factor and its relative error are used to filter out potentially unstable arrays in the construction of the comprehensive data set. Comparisons of the conventional (consisting of dipole-dipole and Wenner-Schlumberger arrays) and optimized arrays are made using a synthetic model and experimental measurements in a tank. The tests show that structures located between the lines are better resolved with the optimized arrays. The optimized arrays also have significantly better depth resolution compared to the conventional arrays.

  8. Sensitivity of an MT Array to 3D Structure Outside the Array Footprint

    NASA Astrophysics Data System (ADS)

    Booker, J. R.; Mackie, R. L.; Burd, A. I.; Pomposiello, M. C.; Favetto, A. B.

    2015-12-01

    Standard data collection strategy in magnetotellurics (MT) is to deploy a profile or array of sites that spans the target of interest. There is no expectation that structure can be imaged outside the area covered by sites. We have inverted two MT arrays for 3D structure under Argentina. The two arrays do not overlap, but serendipitously the 3D model for the northern array overlaps the position of a prominent 3D deep conductive structure seen in the inversion of the southern array. To our surprise this deep southern feature is also imaged by the northern array even though it is well outside the footprint of the northern array. It therefore appears that typical intuition about one's ability to image structure outside the span of the sites is not always true. We present model studies to demonstrate why this is so and under what conditions one can expect a 3D array to be capable of imaging structure outside the array.

  9. Patterns of 3D flow in a rotating cylinder array

    NASA Astrophysics Data System (ADS)

    Craig, Anna; Dabiri, John; Koseff, Jeffrey

    2015-11-01

    Experimental data are presented for large arrays of rotating, finite-height cylinders, which show that the three-dimensional flows are strongly dependent on the geometric and rotational configurations of the array. Two geometric configurations of the cylinders, each with two rotational configurations, were examined for a total of four arrays. 2D PIV was conducted in multiple intersecting horizontal and vertical sheets at a location far downstream of the leading edge of the array in order to build up a picture of the 3D developed flow patterns. It was found that the rotation of the cylinders drives the formation of streamwise and transverse flow patterns between cylinders. These horizontal flow patterns, by conservation of mass, drive vertical flows through the top of the array. As the array of rotating cylinders may provide insight into the flow kinematics of an array of vertical axis wind turbines, this planform flux is of particular interest as it would bring down into the array high kinetic energy fluid from above the array, thus increasing the energy resource available to turbines far downstream of the leading edge of the array.

  10. Density-tapered spiral arrays for ultrasound 3-D imaging.

    PubMed

    Ramalli, Alessandro; Boni, Enrico; Savoia, Alessandro Stuart; Tortoli, Piero

    2015-08-01

    The current high interest in 3-D ultrasound imaging is pushing the development of 2-D probes with a challenging number of active elements. The most popular approach to limit this number is the sparse array technique, which designs the array layout by means of complex optimization algorithms. These algorithms are typically constrained by a few steering conditions, and, as such, cannot guarantee uniform side-lobe performance at all angles. The performance may be improved by the ungridded extensions of the sparse array technique, but this result is achieved at the expense of a further complication of the optimization process. In this paper, a method to design the layout of large circular arrays with a limited number of elements according to Fermat's spiral seeds and spatial density modulation is proposed and shown to be suitable for application to 3-D ultrasound imaging. This deterministic, aperiodic, and balanced positioning procedure attempts to guarantee uniform performance over a wide range of steering angles. The capabilities of the method are demonstrated by simulating and comparing the performance of spiral and dense arrays. A good trade-off for small vessel imaging is found, e.g., in the 60λ spiral array with 1.0λ elements and Blackman density tapering window. Here, the grating lobe level is -16 dB, the lateral resolution is lower than 6λ the depth of field is 120λ and, the average contrast is 10.3 dB, while the sensitivity remains in a 5 dB range for a wide selection of steering angles. The simulation results may represent a reference guide to the design of spiral sparse array probes for different application fields. PMID:26285181

  11. Highly compressible 3D periodic graphene aerogel microlattices.

    PubMed

    Zhu, Cheng; Han, T Yong-Jin; Duoss, Eric B; Golobic, Alexandra M; Kuntz, Joshua D; Spadaccini, Christopher M; Worsley, Marcus A

    2015-01-01

    Graphene is a two-dimensional material that offers a unique combination of low density, exceptional mechanical properties, large surface area and excellent electrical conductivity. Recent progress has produced bulk 3D assemblies of graphene, such as graphene aerogels, but they possess purely stochastic porous networks, which limit their performance compared with the potential of an engineered architecture. Here we report the fabrication of periodic graphene aerogel microlattices, possessing an engineered architecture via a 3D printing technique known as direct ink writing. The 3D printed graphene aerogels are lightweight, highly conductive and exhibit supercompressibility (up to 90% compressive strain). Moreover, the Young's moduli of the 3D printed graphene aerogels show an order of magnitude improvement over bulk graphene materials with comparable geometric density and possess large surface areas. Adapting the 3D printing technique to graphene aerogels realizes the possibility of fabricating a myriad of complex aerogel architectures for a broad range of applications. PMID:25902277

  12. Highly compressible 3D periodic graphene aerogel microlattices

    PubMed Central

    Zhu, Cheng; Han, T. Yong-Jin; Duoss, Eric B.; Golobic, Alexandra M.; Kuntz, Joshua D.; Spadaccini, Christopher M.; Worsley, Marcus A.

    2015-01-01

    Graphene is a two-dimensional material that offers a unique combination of low density, exceptional mechanical properties, large surface area and excellent electrical conductivity. Recent progress has produced bulk 3D assemblies of graphene, such as graphene aerogels, but they possess purely stochastic porous networks, which limit their performance compared with the potential of an engineered architecture. Here we report the fabrication of periodic graphene aerogel microlattices, possessing an engineered architecture via a 3D printing technique known as direct ink writing. The 3D printed graphene aerogels are lightweight, highly conductive and exhibit supercompressibility (up to 90% compressive strain). Moreover, the Young's moduli of the 3D printed graphene aerogels show an order of magnitude improvement over bulk graphene materials with comparable geometric density and possess large surface areas. Adapting the 3D printing technique to graphene aerogels realizes the possibility of fabricating a myriad of complex aerogel architectures for a broad range of applications. PMID:25902277

  13. Highly compressible 3D periodic graphene aerogel microlattices

    SciTech Connect

    Zhu, Cheng; Han, T. Yong-Jin; Duoss, Eric B.; Golobic, Alexandra M.; Kuntz, Joshua D.; Spadaccini, Christopher M.; Worsley, Marcus A.

    2015-04-22

    Graphene is a two-dimensional material that offers a unique combination of low density, exceptional mechanical properties, large surface area and excellent electrical conductivity. Recent progress has produced bulk 3D assemblies of graphene, such as graphene aerogels, but they possess purely stochastic porous networks, which limit their performance compared with the potential of an engineered architecture. Here we report the fabrication of periodic graphene aerogel microlattices, possessing an engineered architecture via a 3D printing technique known as direct ink writing. The 3D printed graphene aerogels are lightweight, highly conductive and exhibit supercompressibility (up to 90% compressive strain). Moreover, the Young’s moduli of the 3D printed graphene aerogels show an order of magnitude improvement over bulk graphene materials with comparable geometric density and possess large surface areas. Ultimately, adapting the 3D printing technique to graphene aerogels realizes the possibility of fabricating a myriad of complex aerogel architectures for a broad range of applications.

  14. 3D electrical tomographic imaging using vertical arrays of electrodes

    NASA Astrophysics Data System (ADS)

    Murphy, S. C.; Stanley, S. J.; Rhodes, D.; York, T. A.

    2006-11-01

    Linear arrays of electrodes in conjunction with electrical impedance tomography have been used to spatially interrogate industrial processes that have only limited access for sensor placement. This paper explores the compromises that are to be expected when using a small number of vertically positioned linear arrays to facilitate 3D imaging using electrical tomography. A configuration with three arrays is found to give reasonable results when compared with a 'conventional' arrangement of circumferential electrodes. A single array yields highly localized sensitivity that struggles to image the whole space. Strategies have been tested on a small-scale version of a sludge settling application that is of relevance to the industrial sponsor. A new electrode excitation strategy, referred to here as 'planar cross drive', is found to give superior results to an extended version of the adjacent electrodes technique due to the improved uniformity of the sensitivity across the domain. Recommendations are suggested for parameters to inform the scale-up to industrial vessels.

  15. Hexagonal liquid crystal lens array for 3D endoscopy.

    PubMed

    Hassanfiroozi, Amir; Huang, Yi-Pai; Javidi, Bahram; Shieh, Han-Ping D

    2015-01-26

    A liquid crystal lens array with a hexagonal arrangement is investigated experimentally. The uniqueness of this study exists in the fact that using convex-ring electrode provides a smooth and controllable applied potential profile across the aperture to manage the phase profile. We observed considerable differences between flat electrode and convex-ring electrode; in particular the lens focal length is variable in a wider range from 2.5cm to infinity. This study presents several noteworthy characteristics such as low driving voltage; 30 μm cell gap and the lens is electrically switchable between 2D/3D modes. We demonstrate a hexagonal LC-lens array for capturing 3D images by using single sensor using integral imaging. PMID:25835856

  16. High-speed 3D shape measurement using array projection

    NASA Astrophysics Data System (ADS)

    Heist, Stefan; Sieler, Marcel; Breitbarth, Andreas; Kühmstedt, Peter; Notni, Gunther

    2013-04-01

    Measuring the three-dimensional (3D) surface shape of objects in real time has become an important task e.g. in industrial quality management or medical sciences. Stereo vision-based arrangements in connection with pattern projection offer high data acquisition speed and low computation time. However, these coded-light techniques are limited by the projection speed which is conventionally in the range of 200. . .250Hz. In this contribution, we present the concepts and a realized setup of a so-called 3D array projector. It is ultra-slim, but nonetheless able to project fixed patterns with high brightness and depth of focus. Furthermore, frame rates up to the 100 kHz range are achievable without any need of mechanically moving parts since the projection speed is limited mainly by the switching frequency of the used LEDs. According to the measurement requirements, type and structure of the patterns can be chosen almost freely: linear or sinusoidal fringes, binary codes such as the Gray code, square, hexagonal or random patterns and many more. First investigations on the functionality of such a 3D array projector were conducted using a prototype with a combination of Gray codes and phase-shifted sinusoidal fringes. Our contribution proves the high brightness of the proposed projector, its sharpness and the good Michelson contrast of the fringe patterns. We deal with the patterns' homogeneity and the accuracy of the phase shift between the sinusoidal patterns. Furthermore, we present first measurement results and outline future research which is, inter alia, addressed to the use of other structured light techniques with the help of new purpose-built 3D array projector prototypes.

  17. 3D printed long period gratings for optical fibers.

    PubMed

    Iezzi, Victor Lambin; Boisvert, Jean-Sébastien; Loranger, Sébastien; Kashyap, Raman

    2016-04-15

    We demonstrate a simple technique for implementing long period grating (LPG) structures by the use of a 3D printer. This Letter shows a way of manipulating the mode coupling within an optical fiber by applying stress through an external 3D printed periodic structure. Different LPG lengths and periods have been studied, as well as the effect of the applied stress on the coupling efficiency from the fundamental mode to cladding modes. The technique is very simple, highly flexible, affordable, and easy to implement without the need of altering the optical fiber. This Letter is part of a growing line of interest in the use of 3D printers for optical applications. PMID:27082365

  18. Real-time, 3-D ultrasound with multiple transducer arrays.

    PubMed

    Fronheiser, Matthew P; Light, Edward D; Idriss, Salim F; Wolf, Patrick D; Smith, Stephen W

    2006-01-01

    Modifications were made to a commercial real-time, three-dimensional (3-D) ultrasound system for near simultaneous 3-D scanning with two matrix array transducers. As a first illustration, a transducer cable assembly was modified to incorporate two independent, 3-D intra-cardiac echo catheters, a 7 Fr (2.3 mm O.D.) side scanning catheter and a 14 Fr (4.7 mm O.D) forward viewing catheter with accessory port, each catheter using 85 channels operating at 5 MHz. For applications in treatment of atrial fibrillation, the goal is to place the sideviewing catheter within the coronary sinus to view the whole left atrium, including a pulmonary vein. Meanwhile, the forward-viewing catheter inserted within the left atrium is directed toward the ostium of a pulmonary vein for therapy using the integrated accessory port. Using preloaded, phasing data, the scanner switches between catheters automatically, at the push of a button, with a delay of about 1 second, so that the clinician can view the therapy catheter with the coronary sinus catheter and vice versa. Preliminary imaging studies in a tissue phantom and in vivo show that our system successfully guided the forward-viewing catheter toward a target while being imaged with the sideviewing catheter. The forward-viewing catheter then was activated to monitor the target while we mimicked therapy delivery. In the future, the system will switch between 3-D probes on a line-by-line basis and display both volumes simultaneously. PMID:16471436

  19. Materials Manufactured from 3D Printed Synthetic Biology Arrays

    NASA Technical Reports Server (NTRS)

    Gentry, Diana; Micks, Ashley

    2013-01-01

    Many complex, biologically-derived materials have extremely useful properties (think wood or silk), but are unsuitable for space-related applications due to production, manufacturing, or processing limitations. Large-scale ecosystem-based production, such as raising and harvesting trees for wood, is impractical in a self-contained habitat such as a space station or potential Mars colony. Manufacturing requirements, such as the specialized equipment needed to harvest and process cotton, add too much upmass for current launch technology. Cells in nature are already highly specialized for making complex biological materials on a micro scale. We envision combining these strengths with the recently emergent technologies of synthetic biology and 3D printing to create 3D-structured arrays of cells that are bioengineered to secrete different materials in a specified three-dimensional pattern.

  20. Tuning the 3D plasmon field of nanohole arrays

    NASA Astrophysics Data System (ADS)

    Couture, Maxime; Liang, Yuzhang; Poirier Richard, Hugo-Pierre; Faid, Rita; Peng, Wei; Masson, Jean-Francois

    2013-11-01

    Modern photonics is being revolutionized through the use of nanostructured plasmonic materials, which confine light to sub-diffraction limit resolution providing universal, sensitive, and simple transducers for molecular sensors. Understanding the mechanisms by which light interacts with plasmonic crystals is essential for developing application-focussed devices. The strong influence of grating coupling on electromagnetic field distribution, frequency and degeneracy of plasmon bands has now been characterized using hexagonal nanohole arrays. An equation for nanohole arrays was derived to demonstrate the strong influence of incidence and rotation angle on optical properties of 2D plasmonic crystals such as nanohole arrays. Consequently, we report experimental data that are in strong agreement with finite difference time-domain (FDTD) simulations that clearly demonstrate the influence of the grating coupling conditions on the optical properties (such as plasmon degeneracy and bandwidth), and on the distribution of the plasmon field around nanohole arrays (including tuneable penetration depths and highly localized fields). The tuneable 3D plasmon field allowed for controlled sensing properties and by increasing the angle of incidence to 30 degrees, the resonance wavelength was tuned from 1000 to 600 nm, and the sensitivity was enhanced by nearly 300% for a protein assay using surface plasmon resonance (SPR) and by 40% with surface-enhanced Raman scattering (SERS) sensors.Modern photonics is being revolutionized through the use of nanostructured plasmonic materials, which confine light to sub-diffraction limit resolution providing universal, sensitive, and simple transducers for molecular sensors. Understanding the mechanisms by which light interacts with plasmonic crystals is essential for developing application-focussed devices. The strong influence of grating coupling on electromagnetic field distribution, frequency and degeneracy of plasmon bands has now been

  1. 3D target array for pulsed multi-sourced radiography

    DOEpatents

    Le Galloudec, Nathalie Joelle

    2016-02-23

    The various technologies presented herein relate to the generation of x-rays and other charged particles. A plurality of disparate source materials can be combined on an array to facilitate fabrication of co-located mixed tips (point sources) which can be utilized to form a polychromatic cloud, e.g., a plurality of x-rays having a range of energies and or wavelengths, etc. The tips can be formed such that the x-rays are emitted in a direction different to other charged particles to facilitate clean x-ray sourcing. Particles, such as protons, can be directionally emitted to facilitate generation of neutrons at a secondary target. The various particles can be generated by interaction of a laser irradiating the array of tips. The tips can be incorporated into a plurality of 3D conical targets, the conical target sidewall(s) can be utilized to microfocus a portion of a laser beam onto the tip material.

  2. Advanced 3D Microfabrication and Demonstration of Arrayed Electrowetting Microprisms

    NASA Astrophysics Data System (ADS)

    Hou, Linlin

    Beam steering is still a major limitation for many electro-optical applications which require wide-angle (+/- 45°), fast (˜ms) and continuous beam steering with a relatively simple and compact system (e.g. Laser radar, holographic 3D displays, etc.) As for the traditional mechanical beam steering approach, a bulky motorized system is limited in performance for switching speed, reliability, and system footprint. Currently available flat panel approaches include liquid crystal optical phased arrays and microelectromechanical systems, which still have major limitations like polarization dependence, small or only limited steering angles and reflective modes only. To satisfy the next generation of beam steering needs, this thesis explores arrayed electrowetting microprisms. Electrowetting prisms operate by voltage modulation of a meniscus between two immiscible liquids by changing the contact angle on a dielectric coated electrode. Electrowetting prism has the advantages of a simple fabrication process, large scale apertures, fast switching speed, low power consumption, and wide continuous steering angles with low operation voltages. This thesis will show that electrowetting prisms theoretically provide optical performance that may supersede the performance of the liquid crystal or MEMS approaches. Presented in this thesis is a full description of the electrowetting prism development from basic single transmissive and reflective millimeter-scale prisms, to the world's first arrayed microprisms (1500 prisms). These efforts include development of a simple and scalable fabrication process, including novel 3D electrode fabrication. 1D beam steering and 2D RGB color-switching are demonstrated. Theoretical analysis and calculation of the beam deflection capability and electrode fill factor are presented. High index oil investigation is also discussed. Although further research is required before the electrowetting prism arrays are ready for real applications, the thesis

  3. 3D Stretchable Arch Ribbon Array Fabricated via Grayscale Lithography

    PubMed Central

    Pang, Yu; Shu, Yi; Shavezipur, Mohammad; Wang, Xuefeng; Mohammad, Mohammad Ali; Yang, Yi; Zhao, Haiming; Deng, Ningqin; Maboudian, Roya; Ren, Tian-Ling

    2016-01-01

    Microstructures with flexible and stretchable properties display tremendous potential applications including integrated systems, wearable devices and bio-sensor electronics. Hence, it is essential to develop an effective method for fabricating curvilinear and flexural microstructures. Despite significant advances in 2D stretchable inorganic structures, large scale fabrication of unique 3D microstructures at a low cost remains challenging. Here, we demonstrate that the 3D microstructures can be achieved by grayscale lithography to produce a curved photoresist (PR) template, where the PR acts as sacrificial layer to form wavelike arched structures. Using plasma-enhanced chemical vapor deposition (PECVD) process at low temperature, the curved PR topography can be transferred to the silicon dioxide layer. Subsequently, plasma etching can be used to fabricate the arched stripe arrays. The wavelike silicon dioxide arch microstructure exhibits Young modulus and fracture strength of 52 GPa and 300 MPa, respectively. The model of stress distribution inside the microstructure was also established, which compares well with the experimental results. This approach of fabricating a wavelike arch structure may become a promising route to produce a variety of stretchable sensors, actuators and circuits, thus providing unique opportunities for emerging classes of robust 3D integrated systems. PMID:27345766

  4. 3D Stretchable Arch Ribbon Array Fabricated via Grayscale Lithography

    NASA Astrophysics Data System (ADS)

    Pang, Yu; Shu, Yi; Shavezipur, Mohammad; Wang, Xuefeng; Mohammad, Mohammad Ali; Yang, Yi; Zhao, Haiming; Deng, Ningqin; Maboudian, Roya; Ren, Tian-Ling

    2016-06-01

    Microstructures with flexible and stretchable properties display tremendous potential applications including integrated systems, wearable devices and bio-sensor electronics. Hence, it is essential to develop an effective method for fabricating curvilinear and flexural microstructures. Despite significant advances in 2D stretchable inorganic structures, large scale fabrication of unique 3D microstructures at a low cost remains challenging. Here, we demonstrate that the 3D microstructures can be achieved by grayscale lithography to produce a curved photoresist (PR) template, where the PR acts as sacrificial layer to form wavelike arched structures. Using plasma-enhanced chemical vapor deposition (PECVD) process at low temperature, the curved PR topography can be transferred to the silicon dioxide layer. Subsequently, plasma etching can be used to fabricate the arched stripe arrays. The wavelike silicon dioxide arch microstructure exhibits Young modulus and fracture strength of 52 GPa and 300 MPa, respectively. The model of stress distribution inside the microstructure was also established, which compares well with the experimental results. This approach of fabricating a wavelike arch structure may become a promising route to produce a variety of stretchable sensors, actuators and circuits, thus providing unique opportunities for emerging classes of robust 3D integrated systems.

  5. 3D Stretchable Arch Ribbon Array Fabricated via Grayscale Lithography.

    PubMed

    Pang, Yu; Shu, Yi; Shavezipur, Mohammad; Wang, Xuefeng; Mohammad, Mohammad Ali; Yang, Yi; Zhao, Haiming; Deng, Ningqin; Maboudian, Roya; Ren, Tian-Ling

    2016-01-01

    Microstructures with flexible and stretchable properties display tremendous potential applications including integrated systems, wearable devices and bio-sensor electronics. Hence, it is essential to develop an effective method for fabricating curvilinear and flexural microstructures. Despite significant advances in 2D stretchable inorganic structures, large scale fabrication of unique 3D microstructures at a low cost remains challenging. Here, we demonstrate that the 3D microstructures can be achieved by grayscale lithography to produce a curved photoresist (PR) template, where the PR acts as sacrificial layer to form wavelike arched structures. Using plasma-enhanced chemical vapor deposition (PECVD) process at low temperature, the curved PR topography can be transferred to the silicon dioxide layer. Subsequently, plasma etching can be used to fabricate the arched stripe arrays. The wavelike silicon dioxide arch microstructure exhibits Young modulus and fracture strength of 52 GPa and 300 MPa, respectively. The model of stress distribution inside the microstructure was also established, which compares well with the experimental results. This approach of fabricating a wavelike arch structure may become a promising route to produce a variety of stretchable sensors, actuators and circuits, thus providing unique opportunities for emerging classes of robust 3D integrated systems. PMID:27345766

  6. Highly compressible 3D periodic graphene aerogel microlattices

    DOE PAGESBeta

    Zhu, Cheng; Han, T. Yong-Jin; Duoss, Eric B.; Golobic, Alexandra M.; Kuntz, Joshua D.; Spadaccini, Christopher M.; Worsley, Marcus A.

    2015-04-22

    Graphene is a two-dimensional material that offers a unique combination of low density, exceptional mechanical properties, large surface area and excellent electrical conductivity. Recent progress has produced bulk 3D assemblies of graphene, such as graphene aerogels, but they possess purely stochastic porous networks, which limit their performance compared with the potential of an engineered architecture. Here we report the fabrication of periodic graphene aerogel microlattices, possessing an engineered architecture via a 3D printing technique known as direct ink writing. The 3D printed graphene aerogels are lightweight, highly conductive and exhibit supercompressibility (up to 90% compressive strain). Moreover, the Young’s modulimore » of the 3D printed graphene aerogels show an order of magnitude improvement over bulk graphene materials with comparable geometric density and possess large surface areas. Ultimately, adapting the 3D printing technique to graphene aerogels realizes the possibility of fabricating a myriad of complex aerogel architectures for a broad range of applications.« less

  7. Hydrogel-encapsulated 3D microwell array for neuronal differentiation.

    PubMed

    Bae, Jun Hyuk; Lee, Jong Min; Chung, Bong Geun

    2016-02-01

    We developed a photo-crosslinkable hydrogel-encapsulated three-dimensional (3D) microwell array for studying embryonic stem (ES) cell-derived neuronal differentiation. ES cells were cultured for 5 d in microwells and were subsequently encapsulated by photo-crosslinkable gelatin methacrylate (GelMA) and polyethylene glycol (PEG) hydrogels for an additional 7 d. We observed that ES cells cultured in PEG microwells became uniform-sized embryoid bodies (EBs) compared to those in GelMA microwells. Although ES cells were encapsulated by photo-crosslinkable GelMA and PEG hydrogels, they were highly viable. We demonstrated that uniform-sized EBs encapsulated by GelMA hydrogels in PEG microwells are largely differentiated into neuronal cells. It was revealed that neurites at the periphery of EBs in PEG microwells largely extended into the interface between GelMA hydrogels and PEG microwells for generating neuronal networks. Therefore, this photo-crosslinkable GelMA hydrogel-encapsulated PEG microwell array could be a potentially powerful tool for neurodegenerative disease applications. PMID:26928882

  8. Calibrating camera and projector arrays for immersive 3D display

    NASA Astrophysics Data System (ADS)

    Baker, Harlyn; Li, Zeyu; Papadas, Constantin

    2009-02-01

    Advances in building high-performance camera arrays [1, 12] have opened the opportunity - and challenge - of using these devices for autostereoscopic display of live 3D content. Appropriate autostereo display requires calibration of these camera elements and those of the display facility for accurate placement (and perhaps resampling) of the acquired video stream. We present progress in exploiting a new approach to this calibration that capitalizes on high quality homographies between pairs of imagers to develop a global optimal solution delivering epipoles and fundamental matrices simultaneously for the entire system [2]. Adjustment of the determined camera models to deliver minimal vertical misalignment in an epipolar sense is used to permit ganged rectification of the separate streams for transitive positioning in the visual field. Individual homographies [6] are obtained for a projector array that presents the video on a holographically-diffused retroreflective surface for participant autostereo viewing. The camera model adjustment means vertical epipolar disparities of the captured signal are minimized, and the projector calibration means the display will retain these alignments despite projector pose variations. The projector calibration also permits arbitrary alignment shifts to accommodate focus-of-attention vengeance, should that information be available.

  9. 1024 pixels single photon imaging array for 3D ranging

    NASA Astrophysics Data System (ADS)

    Bellisai, S.; Guerrieri, F.; Tisa, S.; Zappa, F.; Tosi, A.; Giudice, A.

    2011-01-01

    Three dimensions (3D) acquisition systems are driving applications in many research field. Nowadays 3D acquiring systems are used in a lot of applications, such as cinema industry or in automotive (for active security systems). Depending on the application, systems present different features, for example color sensitivity, bi-dimensional image resolution, distance measurement accuracy and acquisition frame rate. The system we developed acquires 3D movie using indirect Time of Flight (iTOF), starting from phase delay measurement of a sinusoidally modulated light. The system acquires live movie with a frame rate up to 50frame/s in a range distance between 10 cm up to 7.5 m.

  10. Novel and simple route to fabricate 2D ordered gold nanobowl arrays based on 3D colloidal crystals.

    PubMed

    Rao, Yanying; Tao, Qin; An, Ming; Rong, Chunhui; Dong, Jian; Dai, Yurong; Qian, Weiping

    2011-11-01

    In this study, we present a new method to fabricate large-area two-dimensionally (2D) ordered gold nanobowl arrays based on 3D colloidal crystals by wet chemosynthesis, which combines the advantages of a very simple preparation and an applicability to "real" nanomaterials. By combination of in situ growth of gold nanoshell (GNSs) arrays based on three-dimensional (3D) colloidal silica crystals, a monolayer ordered reversed GNS array (2D ordered GNS array) was conveniently manufactured by an acrylic ester modified biaxial oriented polypropylene (BOPP). 2D ordered gold nanobowl array with adjustable periodic holes, good stability, reproducibility, and repeatability could be obtained when the silica core was etched by HF solution. The surface-enhanced Raman scattering (SERS) enhancement factor (EF) of this 2D ordered gold nanobowl array could reach 1.27 × 10(7), which shows high SERS enhancing activity and can be used as a universal SERS substrate. PMID:21932785

  11. 3-D aluminum nanostructure with microhole array synthesized by femtosecond laser radiation for enhanced light extinction

    PubMed Central

    2013-01-01

    This article presents 3-D aluminum micro-nanostructures for enhanced light absorption. Periodic microhole arrays were created by firing a train of femtosecond laser pulses at megahertz pulse frequency onto the surface of an aluminum target at ambient conditions. The laser trains ablated the target surface and created microholes leading to the generation of deposited nanostructures inside and around the microholes. These micro-nanostructures showed enhanced light absorption, which is attributed to surface plasmonics induced by the generation of both nano- and microstructures. These micro-nanostructures may be promising for solar cell applications. PMID:24225364

  12. 3D optical Yagi–Uda nanoantenna array

    PubMed Central

    Dregely, Daniel; Taubert, Richard; Dorfmüller, Jens; Vogelgesang, Ralf; Kern, Klaus; Giessen, Harald

    2011-01-01

    Future photonic circuits with the capability of high-speed data processing at optical frequencies will rely on the implementation of efficient emitters and detectors on the nanoscale. Towards this goal, bridging the size mismatch between optical radiation and subwavelength emitters or detectors by optical nanoantennas is a subject of current research in the field of plasmonics. Here we introduce an array of three-dimensional optical Yagi–Uda antennas, fabricated using top-down fabrication techniques combined with layer-by-layer processing. We show that the concepts of radiofrequency antenna arrays can be applied to the optical regime proving superior directional properties compared with a single planar optical antenna, particularly for emission and reception into the third dimension. Measuring the optical properties of the structure reveals that impinging light on the array is efficiently absorbed on the subwavelength scale because of the high directivity. Moreover, we show in simulations that combining the array with suitable feeding circuits gives rise to the prospect of beam steering at optical wavelengths. PMID:21468019

  13. 3D optical Yagi-Uda nanoantenna array.

    PubMed

    Dregely, Daniel; Taubert, Richard; Dorfmüller, Jens; Vogelgesang, Ralf; Kern, Klaus; Giessen, Harald

    2011-01-01

    Future photonic circuits with the capability of high-speed data processing at optical frequencies will rely on the implementation of efficient emitters and detectors on the nanoscale. Towards this goal, bridging the size mismatch between optical radiation and subwavelength emitters or detectors by optical nanoantennas is a subject of current research in the field of plasmonics. Here we introduce an array of three-dimensional optical Yagi-Uda antennas, fabricated using top-down fabrication techniques combined with layer-by-layer processing. We show that the concepts of radiofrequency antenna arrays can be applied to the optical regime proving superior directional properties compared with a single planar optical antenna, particularly for emission and reception into the third dimension. Measuring the optical properties of the structure reveals that impinging light on the array is efficiently absorbed on the subwavelength scale because of the high directivity. Moreover, we show in simulations that combining the array with suitable feeding circuits gives rise to the prospect of beam steering at optical wavelengths. PMID:21468019

  14. A 3D glass optrode array for optical neural stimulation

    PubMed Central

    Abaya, T.V.F.; Blair, S.; Tathireddy, P.; Rieth, L.; Solzbacher, F.

    2012-01-01

    This paper presents optical characterization of a first-generation SiO2 optrode array as a set of penetrating waveguides for both optogenetic and infrared (IR) neural stimulation. Fused silica and quartz discs of 3-mm thickness and 50-mm diameter were micromachined to yield 10 × 10 arrays of up to 2-mm long optrodes at a 400-μm pitch; array size, length and spacing may be varied along with the width and tip angle. Light delivery and loss mechanisms through these glass optrodes were characterized. Light in-coupling techniques include using optical fibers and collimated beams. Losses involve Fresnel reflection, coupling, scattering and total internal reflection in the tips. Transmission efficiency was constant in the visible and near-IR range, with the highest value measured as 71% using a 50-μm multi-mode in-coupling fiber butt-coupled to the backplane of the device. Transmittance and output beam profiles of optrodes with different geometries was investigated. Length and tip angle do not affect the amount of output power, but optrode width and tip angle influence the beam size and divergence independently. Finally, array insertion in tissue was performed to demonstrate its robustness for optical access in deep tissue. PMID:23243561

  15. 3-D sensing with polar exponential sensor arrays

    NASA Technical Reports Server (NTRS)

    Weiman, Carl F. R.

    1988-01-01

    The present computations for three-dimensional vision involve, in such cases as those of scaling for perspective and optic flow, their reduction to additive operations by the implicit logarithmic transformation of image coordinates. Expressions for such computations are derived and applied to illustrative examples of sensor design. The advantages of polar exponential arrays over X-Y rasters for binocular vision are noted to encompass the inference of range and three-dimensional position from local image velocity without knowledge of pixel location, provided that the relative velocity of the target and sensor are known by some other means.

  16. Dual array 3D electron cyclotron emission imaging at ASDEX Upgrade

    SciTech Connect

    Classen, I. G. J. Bogomolov, A. V.; Domier, C. W.; Luhmann, N. C.; Suttrop, W.; Boom, J. E.; Tobias, B. J.; Donné, A. J. H.

    2014-11-15

    In a major upgrade, the (2D) electron cyclotron emission imaging diagnostic (ECEI) at ASDEX Upgrade has been equipped with a second detector array, observing a different toroidal position in the plasma, to enable quasi-3D measurements of the electron temperature. The new system will measure a total of 288 channels, in two 2D arrays, toroidally separated by 40 cm. The two detector arrays observe the plasma through the same vacuum window, both under a slight toroidal angle. The majority of the field lines are observed by both arrays simultaneously, thereby enabling a direct measurement of the 3D properties of plasma instabilities like edge localized mode filaments.

  17. Dual array 3D electron cyclotron emission imaging at ASDEX Upgrade.

    PubMed

    Classen, I G J; Domier, C W; Luhmann, N C; Bogomolov, A V; Suttrop, W; Boom, J E; Tobias, B J; Donné, A J H

    2014-11-01

    In a major upgrade, the (2D) electron cyclotron emission imaging diagnostic (ECEI) at ASDEX Upgrade has been equipped with a second detector array, observing a different toroidal position in the plasma, to enable quasi-3D measurements of the electron temperature. The new system will measure a total of 288 channels, in two 2D arrays, toroidally separated by 40 cm. The two detector arrays observe the plasma through the same vacuum window, both under a slight toroidal angle. The majority of the field lines are observed by both arrays simultaneously, thereby enabling a direct measurement of the 3D properties of plasma instabilities like edge localized mode filaments. PMID:25430246

  18. Virtual 3D interactive system with embedded multiwavelength optical sensor array and sequential devices

    NASA Astrophysics Data System (ADS)

    Wang, Guo-Zhen; Huang, Yi-Pai; Hu, Kuo-Jui

    2012-06-01

    We proposed a virtual 3D-touch system by bare finger, which can detect the 3-axis (x, y, z) information of finger. This system has multi-wavelength optical sensor array embedded on the backplane of TFT panel and sequentail devices on the border of TFT panel. We had developed reflecting mode which can be worked by bare finger for the 3D interaction. A 4-inch mobile 3D-LCD with this proposed system was successfully been demonstrated already.

  19. Rapid Assembly of Heterogeneous 3D Cell Microenvironments in a Microgel Array.

    PubMed

    Li, Yiwei; Chen, Pu; Wang, Yachao; Yan, Shuangqian; Feng, Xiaojun; Du, Wei; Koehler, Stephan A; Demirci, Utkan; Liu, Bi-Feng

    2016-05-01

    Heterogeneous 3D cell microenvironment arrays are rapidly assembled by combining surface-wettability-guided assembly and microdroplet-array-based operations. This approach enables precise control over individual shapes, sizes, chemical concentrations, cell density, and 3D spatial distribution of multiple components. This technique provides a cost-effective solution to meet the increasing demand of stem cell research, tissue engineering, and drug screening. PMID:26991071

  20. A hybrid antenna array design for 3-d direction of arrival estimation.

    PubMed

    Saqib, Najam-Us; Khan, Imdad

    2015-01-01

    A 3-D beam scanning antenna array design is proposed that gives a whole 3-D spherical coverage and also suitable for various radar and body-worn devices in the Body Area Networks applications. The Array Factor (AF) of the proposed antenna is derived and its various parameters like directivity, Half Power Beam Width (HPBW) and Side Lobe Level (SLL) are calculated by varying the size of the proposed antenna array. Simulations were carried out in MATLAB 2012b. The radiators are considered isotropic and hence mutual coupling effects are ignored. The proposed array shows a considerable improvement against the existing cylindrical and coaxial cylindrical arrays in terms of 3-D scanning, size, directivity, HPBW and SLL. PMID:25790103

  1. Novel volumetric 3D display based on point light source optical reconstruction using multi focal lens array

    NASA Astrophysics Data System (ADS)

    Lee, Jin su; Lee, Mu young; Kim, Jun oh; Kim, Cheol joong; Won, Yong Hyub

    2015-03-01

    Generally, volumetric 3D display panel produce volume-filling three dimensional images. This paper discusses a volumetric 3D display based on periodical point light sources(PLSs) construction using a multi focal lens array(MFLA). The voxel of discrete 3D images is formed in the air via construction of point light source emitted by multi focal lens array. This system consists of a parallel beam, a spatial light modulator(SLM), a lens array, and a polarizing filter. The multi focal lens array is made with UV adhesive polymer droplet control using a dispersing machine. The MFLA consists of 20x20 circular lens array. Each lens aperture of the MFLA shows 300um on average. The polarizing filter is placed after the SLM and the MFLA to set in phase mostly mode. By the point spread function, the PLSs of the system are located by the focal length of each lens of the MFLA. It can also provide the moving parallax and relatively high resolution. However it has a limit of viewing angle and crosstalk by a property of each lens. In our experiment, we present the letter `C', `O', `DE' and ball's surface with the different depth location. It could be seen clearly that when CCD camera is moved to its position following as transverse axis of the display system. From our result, we expect that varifocal lens like EWOD and LC-lens can be applied for real time volumetric 3D display system.

  2. Stacked 3D RRAM Array with Graphene/CNT as Edge Electrodes.

    PubMed

    Bai, Yue; Wu, Huaqiang; Wang, Kun; Wu, Riga; Song, Lin; Li, Tianyi; Wang, Jiangtao; Yu, Zhiping; Qian, He

    2015-01-01

    There are two critical challenges which determine the array density of 3D RRAM: 1) the scaling limit in both horizontal and vertical directions; 2) the integration of selector devices in 3D structure. In this work, we present a novel 3D RRAM structure using low-dimensional materials, including 2D graphene and 1D carbon nanotube (CNT), as the edge electrodes. A two-layer 3D RRAM with monolayer graphene as edge electrode is demonstrated. The electrical results reveal that the RRAM devices could switch normally with this very thin edge electrode at nanometer scale. Meanwhile, benefited from the asymmetric carrier transport induced by Schottky barrier at metal/CNT and oxide/CNT interfaces, a selector built-in 3D RRAM structure using CNT as edge electrode is successfully fabricated and characterized. Furthermore, the discussion of high array density potential is presented. PMID:26348797

  3. Stacked 3D RRAM Array with Graphene/CNT as Edge Electrodes

    PubMed Central

    Bai, Yue; Wu, Huaqiang; Wang, Kun; Wu, Riga; Song, Lin; Li, Tianyi; Wang, Jiangtao; Yu, Zhiping; Qian, He

    2015-01-01

    There are two critical challenges which determine the array density of 3D RRAM: 1) the scaling limit in both horizontal and vertical directions; 2) the integration of selector devices in 3D structure. In this work, we present a novel 3D RRAM structure using low-dimensional materials, including 2D graphene and 1D carbon nanotube (CNT), as the edge electrodes. A two-layer 3D RRAM with monolayer graphene as edge electrode is demonstrated. The electrical results reveal that the RRAM devices could switch normally with this very thin edge electrode at nanometer scale. Meanwhile, benefited from the asymmetric carrier transport induced by Schottky barrier at metal/CNT and oxide/CNT interfaces, a selector built-in 3D RRAM structure using CNT as edge electrode is successfully fabricated and characterized. Furthermore, the discussion of high array density potential is presented. PMID:26348797

  4. 3D Dewetting for Crystal Patterning: Toward Regular Single-Crystalline Belt Arrays and Their Functionality.

    PubMed

    Wu, Yuchen; Feng, Jiangang; Su, Bin; Jiang, Lei

    2016-03-01

    Arrays of unidirectional dewetting behaviors can be generated by using 3D-wettability-difference micropillars, yielding highly ordered organic single-crystalline belt arrays. These patterned organic belts show an improved mobility record and can be used as flexible pressure sensors with high sensitivity. PMID:26823061

  5. 3D Dose Verification Using Tomotherapy CT Detector Array

    SciTech Connect

    Sheng Ke; Jones, Ryan; Yang Wensha; Saraiya, Siddharth; Schneider, Bernard; Chen Quan; Sobering, Geoff; Olivera, Gustavo; Read, Paul

    2012-02-01

    Purpose: To evaluate a three-dimensional dose verification method based on the exit dose using the onboard detector of tomotherapy. Methods and Materials: The study included 347 treatment fractions from 24 patients, including 10 prostate, 5 head and neck (HN), and 9 spinal stereotactic body radiation therapy (SBRT) cases. Detector sonograms were retrieved and back-projected to calculate entrance fluence, which was then forward-projected on the CT images to calculate the verification dose, which was compared with ion chamber and film measurement in the QA plans and with the planning dose in patient plans. Results: Root mean square (RMS) errors of 2.0%, 2.2%, and 2.0% were observed comparing the dose verification (DV) and the ion chamber measured point dose in the phantom plans for HN, prostate, and spinal SBRT patients, respectively. When cumulative dose in the entire treatment is considered, for HN patients, the error of the mean dose to the planning target volume (PTV) varied from 1.47% to 5.62% with a RMS error of 3.55%. For prostate patients, the error of the mean dose to the prostate target volume varied from -5.11% to 3.29%, with a RMS error of 2.49%. The RMS error of maximum doses to the bladder and the rectum were 2.34% (-4.17% to 2.61%) and 2.64% (-4.54% to 3.94%), respectively. For the nine spinal SBRT patients, the RMS error of the minimum dose to the PTV was 2.43% (-5.39% to 2.48%). The RMS error of maximum dose to the spinal cord was 1.05% (-2.86% to 0.89%). Conclusions: An excellent agreement was observed between the measurement and the verification dose. In the patient treatments, the agreement in doses to the majority of PTVs and organs at risk is within 5% for the cumulative treatment course doses. The dosimetric error strongly depends on the error in multileaf collimator leaf opening time with a sensitivity correlating to the gantry rotation period.

  6. In vivo bone response to 3D periodic hydroxyapatite scaffolds assembled by direct ink writing.

    PubMed

    Simon, Joshua L; Michna, Sarah; Lewis, Jennifer A; Rekow, E Dianne; Thompson, Van P; Smay, James E; Yampolsky, Andrew; Parsons, J Russell; Ricci, John L

    2007-12-01

    The in vivo bone response of 3D periodic hydroxyapatite (HA) scaffolds is investigated. Two groups of HA scaffolds (11 mm diameter x 3.5 mm thick) are fabricated by direct-write assembly of a concentrated HA ink. The scaffolds consist of cylindrical rods periodically arranged into four quadrants with varying separation distances between rods. In the first group, HA rods (250 microm in diameter) are patterned to create pore channels, whose areal dimensions are 250 x 250 microm(2) in quadrant 1, 250 x 500 microm(2) in quadrants 2 and 4, and 500 x 500 microm(2) in quadrant 3. In the second group, HA rods (400 microm in diameter) are patterned to create pore channels, whose areal dimensions of 500 x 500 microm(2) in quadrant 1, 500 x 750 microm(2) in quadrants 2 and 4, and 750 x 750 microm(2) in quadrant 3. Each group of scaffolds is partially densified by sintering at 1200 degrees C prior to being implanted bilaterally in trephine defects of skeletally mature New Zealand White rabbits. Their tissue response is evaluated at 8 and 16 weeks using micro-computed tomography, histology, and scanning electron microscopy. New trabecular bone is conducted rapidly and efficiently across substantial distances within these patterned 3D HA scaffolds. Our observations suggest that HA rods are first coated with a layer of new bone followed by subsequent scaffold infilling via outward and inward radial growth of the coated regions. Direct-write assembly of 3D periodic scaffolds composed of micro-porous HA rods arrayed to produce macro-pores that are size-matched to trabecular bone may represent an optimal strategy for bone repair and replacement structures. PMID:17559109

  7. Laser fabrication of 2D and 3D metal nanoparticle structures and arrays.

    PubMed

    Kuznetsov, A I; Kiyan, R; Chichkov, B N

    2010-09-27

    A novel method for fabrication of 2D and 3D metal nanoparticle structures and arrays is proposed. This technique is based on laser-induced transfer of molten metal nanodroplets from thin metal films. Metal nanoparticles are produced by solidification of these nanodroplets. The size of the transferred nanoparticles can be controllably changed in the range from 180 nm to 1500 nm. Several examples of complex 2D and 3D microstructures generated form gold nanoparticles are demonstrated. PMID:20941016

  8. A Dual-Layer Transducer Array for 3-D Rectilinear Imaging

    PubMed Central

    Yen, Jesse T.; Seo, Chi Hyung; Awad, Samer I.; Jeong, Jong S.

    2010-01-01

    2-D arrays for 3-D rectilinear imaging require very large element counts (16,000–65,000). The difficulties in fabricating and interconnecting 2-D arrays with a large number of elements (>5,000) have limited the development of suitable transducers for 3-D rectilinear imaging. In this paper, we propose an alternative solution to this problem by using a dual-layer transducer array design. This design consists of two perpendicular 1-D arrays for clinical 3-D imaging of targets near the transducer. These targets include the breast, carotid artery, and musculoskeletal system. This transducer design reduces the fabrication complexity and the channel count making 3-D rectilinear imaging more realizable. With this design, an effective N × N 2-D array can be developed using only N transmitters and N receivers. This benefit becomes very significant when N becomes greater than 128, for example. To demonstrate feasibility, we constructed a 4 × 4 cm prototype dual-layer array. The transmit array uses diced PZT-5H elements, and the receive array is a single sheet of undiced P[VDF-TrFE] copolymer. The receive elements are defined by the copper traces on the flexible interconnect circuit. The measured −6 dB fractional bandwidth was 80% with a center frequency of 4.8 MHz. At 5 MHz, the nearest neighbor crosstalk of the PZT array and PVDF array was −30.4 ± 3.1 dB and −28.8 ± 3.7 dB respectively. This dual-layer transducer was interfaced with an Ultrasonix Sonix RP system, and a synthetic aperture 3-D data set was acquired. We then performed off-line 3-D beamforming to obtain volumes of nylon wire targets. The theoretical lateral beamwidth was 0.52 mm compared to measured beamwidths of 0.65 mm and 0.67 mm in azimuth and elevation respectively. 3-D images of an 8 mm diameter anechoic cyst phantom were also acquired. PMID:19213647

  9. Additively Manufactured Device for Dynamic Culture of Large Arrays of 3D Tissue Engineered Constructs.

    PubMed

    Costa, Pedro F; Hutmacher, Dietmar W; Theodoropoulos, Christina; Gomes, Manuela E; Reis, Rui L; Vaquette, Cédryck

    2015-04-22

    The ability to test large arrays of cell and biomaterial combinations in 3D environments is still rather limited in the context of tissue engineering and regenerative medicine. This limitation can be generally addressed by employing highly automated and reproducible methodologies. This study reports on the development of a highly versatile and upscalable method based on additive manufacturing for the fabrication of arrays of scaffolds, which are enclosed into individualized perfusion chambers. Devices containing eight scaffolds and their corresponding bioreactor chambers are simultaneously fabricated utilizing a dual extrusion additive manufacturing system. To demonstrate the versatility of the concept, the scaffolds, while enclosed into the device, are subsequently surface-coated with a biomimetic calcium phosphate layer by perfusion with simulated body fluid solution. 96 scaffolds are simultaneously seeded and cultured with human osteoblasts under highly controlled bidirectional perfusion dynamic conditions over 4 weeks. Both coated and noncoated resulting scaffolds show homogeneous cell distribution and high cell viability throughout the 4 weeks culture period and CaP-coated scaffolds result in a significantly increased cell number. The methodology developed in this work exemplifies the applicability of additive manufacturing as a tool for further automation of studies in the field of tissue engineering and regenerative medicine. PMID:25721231

  10. Radial electric field 3D modeling for wire arrays driving dynamic hohlraums on Z.

    SciTech Connect

    Mock, Raymond Cecil

    2007-06-01

    The anode-cathode structure of the Z-machine wire array results in a higher negative radial electric field (Er) on the wires near the cathode relative to the anode. The magnitude of this field has been shown to anti-correlate with the axial radiation top/bottom symmetry in the DH (Dynamic Hohlraum). Using 3D modeling, the structure of this field is revealed for different wire-array configurations and for progressive mechanical alterations, providing insight for minimizing the negative Er on the wire array in the anode-to-cathode region of the DH. Also, the 3D model is compared to Sasorov's approximation, which describes Er at the surface of the wire in terms of wire-array parameters.

  11. Electrochemical signal amplification for immunosensor based on 3D interdigitated array electrodes.

    PubMed

    Han, Donghoon; Kim, Yang-Rae; Kang, Chung Mu; Chung, Taek Dong

    2014-06-17

    We devised an electrochemical redox cycling based on three-dimensional interdigitated array (3D IDA) electrodes for signal amplification to enhance the sensitivity of chip-based immunosensors. The 3D IDA consists of two closely spaced parallel indium tin oxide (ITO) electrodes that are positioned not only on the bottom but also the ceiling, facing each other along a microfluidic channel. We investigated the signal intensities from various geometric configurations: Open-2D IDA, Closed-2D IDA, and 3D IDA through electrochemical experiments and finite-element simulations. The 3D IDA among the four different systems exhibited the greatest signal amplification resulting from efficient redox cycling of electroactive species confined in the microchannel so that the faradaic current was augmented by a factor of ∼100. We exploited the enhanced sensitivity of the 3D IDA to build up a chronocoulometric immunosensing platform based on the sandwich enzyme-linked immunosorbent assay (ELISA) protocol. The mouse IgGs on the 3D IDA showed much lower detection limits than on the Closed-2D IDA. The detection limit for mouse IgG measured using the 3D IDA was ∼10 fg/mL, while it was ∼100 fg/mL for the Closed-2D IDA. Moreover, the proposed immunosensor system with the 3D IDA successfully worked for clinical analysis as shown by the sensitive detection of cardiac troponin I in human serum down to 100 fg/mL. PMID:24842332

  12. Design of crossed-mirror array to form floating 3D LED signs

    NASA Astrophysics Data System (ADS)

    Yamamoto, Hirotsugu; Bando, Hiroki; Kujime, Ryousuke; Suyama, Shiro

    2012-03-01

    3D representation of digital signage improves its significance and rapid notification of important points. Our goal is to realize floating 3D LED signs. The problem is there is no sufficient device to form floating 3D images from LEDs. LED lamp size is around 1 cm including wiring and substrates. Such large pitch increases display size and sometimes spoils image quality. The purpose of this paper is to develop optical device to meet the three requirements and to demonstrate floating 3D arrays of LEDs. We analytically investigate image formation by a crossed mirror structure with aerial aperture, called CMA (crossed-mirror array). CMA contains dihedral corner reflectors at each aperture. After double reflection, light rays emitted from an LED will converge into the corresponding image point. We have fabricated CMA for 3D array of LEDs. One CMA unit contains 20 x 20 apertures that are located diagonally. Floating image of LEDs was formed in wide range of incident angle. The image size of focused beam agreed to the apparent aperture size. When LEDs were located three-dimensionally (LEDs in three depths), the focused distances were the same as the distance between the real LED and the CMA.

  13. 3D imaging LADAR with linear array devices: laser, detector and ROIC

    NASA Astrophysics Data System (ADS)

    Kameyama, Shumpei; Imaki, Masaharu; Tamagawa, Yasuhisa; Akino, Yosuke; Hirai, Akihito; Ishimura, Eitaro; Hirano, Yoshihito

    2009-07-01

    This paper introduces the recent development of 3D imaging LADAR (LAser Detection And Ranging) in Mitsubishi Electric Corporation. The system consists of in-house-made key devices which are linear array: the laser, the detector and the ROIC (Read-Out Integrated Circuit). The laser transmitter is the high power and compact planar waveguide array laser at the wavelength of 1.5 micron. The detector array consists of the low excess noise Avalanche Photo Diode (APD) using the InAlAs multiplication layer. The analog ROIC array, which is fabricated in the SiGe- BiCMOS process, includes the Trans-Impedance Amplifiers (TIA), the peak intensity detectors, the Time-Of-Flight (TOF) detectors, and the multiplexers for read-out. This device has the feature in its detection ability for the small signal by optimizing the peak intensity detection circuit. By combining these devices with the one dimensional fast scanner, the real-time 3D range image can be obtained. After the explanations about the key devices, some 3D imaging results are demonstrated using the single element key devices. The imaging using the developed array devices is planned in the near future.

  14. High-resistance liquid-crystal lens array for rotatable 2D/3D autostereoscopic display.

    PubMed

    Chang, Yu-Cheng; Jen, Tai-Hsiang; Ting, Chih-Hung; Huang, Yi-Pai

    2014-02-10

    A 2D/3D switchable and rotatable autostereoscopic display using a high-resistance liquid-crystal (Hi-R LC) lens array is investigated in this paper. Using high-resistance layers in an LC cell, a gradient electric-field distribution can be formed, which can provide a better lens-like shape of the refractive-index distribution. The advantages of the Hi-R LC lens array are its 2D/3D switchability, rotatability (in the horizontal and vertical directions), low driving voltage (~2 volts) and fast response (~0.6 second). In addition, the Hi-R LC lens array requires only a very simple fabrication process. PMID:24663563

  15. Enhanced Optical Transmission Mediated by Localized Plasmons in Anisotropic, 3D Nanohole Arrays

    PubMed Central

    Yang, Jiun-Chan; Gao, Hanwei; Suh, Jae Yong; Zhou, Wei; Lee, Min Hyung; Odom, Teri W.

    2010-01-01

    This paper describes 3D nanohole arrays whose high optical transmission is mediated more by localized surface plasmon (LSP) excitations than by surface plasmon polaritons (SPPs). First, LSPs on 3D hole arrays lead to optical transmission an order of magnitude higher than 2D planar hole arrays. Second, LSP-mediated transmission is broadband and more tunable than SPP-enhanced transmission which is restricted by Bragg coupling. Third, for the first time, two types of surface plasmons can be selectively excited and manipulated on the same plasmonic substrate. This new plasmonic substrate fabricated by high-throughput nanolithography techniques paves the way for cutting-edge optoelectronic and biomedical applications. PMID:20698633

  16. Concentrated hydroxyapatite inks for direct-write assembly of 3-D periodic scaffolds.

    PubMed

    Michna, Sarah; Wu, Willie; Lewis, Jennifer A

    2005-10-01

    Hydroxyapatite (HA) scaffolds with a 3-D periodic architecture and multiscale porosity have been fabricated by direct-write assembly. Concentrated HA inks with tailored viscoelastic properties were developed to enable the construction of complex 3-D architectures comprised of self-supporting cylindrical rods in a layer-by-layer patterning sequence. By controlling their lattice constant and sintering conditions, 3-D periodic HA scaffolds were produced with a bimodal pore size distribution. Mercury intrusion porosimetry (MIP) was used to determine the characteristic pore size and volume associated with the interconnected pore channels between HA rods and the finer pores within the partially sintered HA rods. PMID:15878368

  17. 7.5 MHz dual-layer transducer array for 3-D rectilinear imaging.

    PubMed

    Chen, Yuling; Nguyen, Man; Yen, Jesse T

    2011-07-01

    The difficulties associated with fabrication and interconnection have limited the development of 2-D ultrasound transducer arrays with a large number ofelements (>5000). In previous work, we described a 5 MHz center frequency PZT-P[VDF-TrFE] dual-layer transducer that used two perpendicular 1-D arrays for 3-D rectilinear imaging. This design substantially reduces the channel count as well as fabrication complexity, which makes 3-D imaging more realizable. Higher frequencies (>5 MHz) are more commonly used in clinical applications or imaging targets near transducers, such as the breast, carotid and musculoskeletal tissue. In this paper, we present a 7.5 MHz dual-layer transducer array for 3-D rectilinear imaging. A modified acoustic stack model was designed and fabricated. PZT elements were sub-diced to eliminate lateral coupling. This sub-dicing process made the PZT into a 2-2 composite material, which could help improve transducer sensitivity and bandwidth. Full synthetic-aperture 3-D data sets were acquired by interfacing the transducer with a Verasonics data-acquisition system (VDAS). Offline 3-D beamforming was then performed to obtain volumes of a multiwire phantom and a cyst phantom. The generalized coherence factor (GCF) was applied to improve the contrast of cyst images. The measured -6 dB fractional bandwidth of the transducer was 71% with a center frequency of 7.5 MHz. The measured lateral beamwidths were 0.521 mm and 0.482 mm in azimuth and elevation, respectively, compared with a simulated beamwidth of 0.43 mm. PMID:21842584

  18. A 7.5 MHz Dual-Layer Transducer Array for 3-D Rectilinear Imaging

    PubMed Central

    Chen, Yuling; Nguyen, Man; Yen, Jesse T.

    2011-01-01

    The difficulties associated with fabrication and interconnection have limited the development of 2-D ultrasound transducer arrays with a large number of elements (>5000). In previous work, we described a 5 MHz center frequency PZT-P[VDF-TrFE] dual-layer transducer, which used 2 perpendicular 1-D arrays for 3-D rectilinear imaging. This design substantially reduces the channel count as well as fabrication complexity, which makes 3-D imaging more realizable. Higher frequencies (>5MHz) are more commonly used in clinical for imaging targets near transducers such as the breast, carotid, and musculoskeletal. In this paper, we present a 7.5 MHz dual-layer transducer array for 3-D rectilinear imaging. A modified acoustic stack model was designed and fabricated. PZT elements were sub-diced to eliminate lateral coupling. This sub-dicing process made the PZT into a 2–2 composite material, which could help improve transducer sensitivity and bandwidth. Full synthetic aperture 3-D data sets were acquired by interfacing the transducer with a Verasonics data acquisition system (VDAS). Offline 3-D beamforming was then performed to obtain volumes of a multi-wire phantom and a cyst phantom. The generalized coherence factor (GCF) was applied to improve the contrast of cyst images. The measured −6 dB fractional bandwidth of the transducer was 71% with a center frequency of 7.5 MHz. The measured lateral beamwidths were 0.521 mm and 0.482 mm in azimuth and elevation respectively, compared with a simulated beamwidth of 0.43 mm. PMID:21842584

  19. n-ZnO/p-Si 3D heterojunction solar cells in Si holey arrays

    NASA Astrophysics Data System (ADS)

    Zhang, Xiao-Mei; Golberg, Dmitri; Bando, Yoshio; Fukata, Naoki

    2012-01-01

    A wafer-scale, low-cost solar cell based on n-ZnO/p-Si 3D heterojunction arrays on holey Si substrates has been fabricated. This device shows a power-conversion efficiency of 1.2% and high photosensitivity. The present n-ZnO/p-Si heterojunction architectures are envisaged as potentially valuable candidates for next-generation photovoltaics.A wafer-scale, low-cost solar cell based on n-ZnO/p-Si 3D heterojunction arrays on holey Si substrates has been fabricated. This device shows a power-conversion efficiency of 1.2% and high photosensitivity. The present n-ZnO/p-Si heterojunction architectures are envisaged as potentially valuable candidates for next-generation photovoltaics. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr11752e

  20. Universal gates based on targeted phase shifts in a 3D neutral atom array

    NASA Astrophysics Data System (ADS)

    Kumar, Aishwarya; Wang, Yang; Wu, Tsung-Yao; Weiss, David

    2016-05-01

    We demonstrate a new approach to making targeted single qubit gates using Cesium atoms in a 5x5x5 3D neutral atom array. It combines targeted AC Zeeman phase shifts with global microwave pulses to produce arbitrary single qubit gates. Non-targeted atoms are left virtually untouched by the gates. We have addressed 48 sites, targeted individually, in a 40% full array. We have also performed Randomized Benchmarking to characterize the fidelity and crosstalk errors of this gate. These gates are highly insensitive to addressing beam imperfections and can be applied to other systems and geometries. Supported by NSF.

  1. 3D probe array integrated with a front-end 100-channel neural recording ASIC

    NASA Astrophysics Data System (ADS)

    Cheng, Ming-Yuan; Yao, Lei; Tan, Kwan Ling; Lim, Ruiqi; Li, Peng; Chen, Weiguo

    2014-12-01

    Brain-machine interface technology can improve the lives of spinal cord injury victims and amputees. A neural interface system, consisting of a 3D probe array and a custom low-power (1 mW) 100-channel (100-ch) neural recording application-specific integrated circuit (ASIC), was designed and implemented to monitor neural activity. In this study, a microassembly 3D probe array method using a novel lead transfer technique was proposed to overcome the bonding plane mismatch encountered during orthogonal assembly. The proposed lead transfer technique can be completed using standard micromachining and packaging processes. The ASIC can be stacking-integrated with the probe array, minimizing the form factor of the assembled module. To minimize trauma to brain cells, the profile of the integrated probe array was controlled within 730 μm. The average impedance of the assembled probe was approximately 0.55 MΩ at 1 kHz. To verify the functionality of the integrated neural probe array, bench-top signal acquisitions were performed and discussed.

  2. A 5 MHz Cylindrical Dual-Layer Transducer Array for 3-D Transrectal Ultrasound Imaging

    PubMed Central

    Chen, Yuling; Nguyen, Man; Yen, Jesse T.

    2012-01-01

    2-D transrectal ultrasound (TRUS) is being used in guiding prostate biopsies and treatments. In many cases, the TRUS probes are moved manually or mechanically to acquire volumetric information, making the imaging slow, user-dependent and unreliable. A real-time 3-D TRUS system could improve reliability and volume rates of imaging during these procedures. In this paper, we present a 5 MHz cylindrical dual-layer transducer array capable of real-time 3-D transrectal ultrasound without any mechanically moving parts. Compared to fully-sampled 2-D arrays, this design substantially reduces the channel count and fabrication complexity. This dual-layer transducer uses PZT elements for transmit and P[VDF-TrFE] copolymer elements for receive, respectively. The mechanical flexibility of both diced PZT and copolymer makes it practical for transrectal applications. Full synthetic aperture 3-D data sets were acquired by interfacing the transducer with a Verasonics Data Acquisition System (VDAS). Offline 3-D beamforming was then performed to obtain volumes of two wire phantoms and a cyst phantom. Generalized coherence factor (GCF) was applied to improve the contrast of images. The measured −6 dB fractional bandwidth of the transducer was 62% with a center frequency of 5.66 MHz. The measured lateral beamwidths were 1.28 mm and 0.91 mm in transverse and longitudinal directions respectively, compared with a simulated beamwidth of 0.92 mm and 0.74 mm. PMID:22972914

  3. Evaporative Self-Assembly of Gold Nanorods into Macroscopic 3D Plasmonic Superlattice Arrays.

    PubMed

    Li, Penghui; Li, Yong; Zhou, Zhang-Kai; Tang, Siying; Yu, Xue-Feng; Xiao, Shu; Wu, Zhongzhen; Xiao, Quanlan; Zhao, Yuetao; Wang, Huaiyu; Chu, Paul K

    2016-04-01

    Millimeter-scale 3D superlattice arrays composed of dense, regular, and vertically aligned gold nanorods are fabricated by evaporative self-assembly. The regular organization of the gold nanorods into a macroscopic superlattice enables the production of a plasmonic substrate with excellent sensitivity and reproducibility, as well as reliability in surface-enhanced Raman scattering. The work bridges the gap between nanoscale materials and macroscopic applications. PMID:26823278

  4. Design and fabrication of a freeform prism array for 3D microscopy.

    PubMed

    Li, Lei; Yi, Allen Y

    2010-12-01

    Traditional microscopes have limitations in obtaining true 3D (three-dimensional) stereovision. Although some optical microscopes have been developed for 3D vision, many of them are complex, expensive, or limited to transparent samples. In this research, a freeform optical prism array was designed and fabricated to achieve 3D stereo imaging capability for microscope and machine vision applications. To form clear stereo images from multiple directions simultaneously, freeform optical surface design was applied to the prisms. In a ray tracing operation to determine the optical performance of the freeform prisms, Taylor series was used to calculate the surface shape. The virtual image spot diagrams were generated by using ray tracing methods for both the freeform prisms and the regular prisms. The results showed that all the light rays can be traced back to a single point for the freeform prism, and aberration was much smaller than that of the regular prism. The ray spots formed by the freeform prisms were adequate for image formation. Furthermore, the freeform prism array was fabricated by using a combined ultraprecision diamond turning and slow tool servo broaching process in a single, uninterrupted operation. The slow tool servo process ensured that the relative tolerance among prisms is guaranteed by the precision of the ultraprecision machine without the need for assembly. Finally 3D imaging tests were conducted to verify the freeform prism array's optical performance. The principle of the freeform prism array investigated in this research can be applied to microscopy, machine vision, robotic sensing, and many other areas. PMID:21119746

  5. Small pitch fringe projection method with multiple linear fiber arrays for 3D shape measurement

    NASA Astrophysics Data System (ADS)

    Hayashi, Takumi; Fujigaki, Motoharu; Murata, Yorinobu

    2014-07-01

    3-D shape measurement systems by contactless method are required in the quality inspections of metal molds and electronic parts in industrial fields. A grating projection method with phase-shifting method has advantages of high precision and high speed. Recently, the size of a BGA (ball grid array) becomes smaller. So the pitch of a grating pattern projected onto the specimen should be smaller. In conventional method, fringe pattern is projected using an imaging lens. The focal depth becomes smaller in the case of reduced projection. It is therefore difficult to project a grating pattern with small pitch onto an object with large incident angles. Authors recently proposed a light source stepping method using a linear LED device. It is easy to shrink the projected grating pitch with a lens because this projection method does not use an imaging lens. The pitch of the projected grating depends on the width of the light source. There is a limit to shrink the projected grating pitch according to the size of the LED chip. In this paper, a small pitch fringe projection method with multiple linear fiber arrays for 3D shape measurement is proposed. The width of the fiber array is 30μm. It is one digit smaller than the width of the LED chip. The experimental result of 3-D shape measurement with small pitch projection with large incident angles is shown.

  6. On-chip clearing of arrays of 3-D cell cultures and micro-tissues.

    PubMed

    Grist, S M; Nasseri, S S; Poon, T; Roskelley, C; Cheung, K C

    2016-07-01

    Three-dimensional (3-D) cell cultures are beneficial models for mimicking the complexities of in vivo tissues, especially in tumour studies where transport limitations can complicate response to cancer drugs. 3-D optical microscopy techniques are less involved than traditional embedding and sectioning, but are impeded by optical scattering properties of the tissues. Confocal and even two-photon microscopy limit sample imaging to approximately 100-200 μm depth, which is insufficient to image hypoxic spheroid cores. Optical clearing methods have permitted high-depth imaging of tissues without physical sectioning, but they are difficult to implement for smaller 3-D cultures due to sample loss in solution exchange. In this work, we demonstrate a microfluidic platform for high-throughput on-chip optical clearing of breast cancer spheroids using the SeeDB, Clear(T2), and ScaleSQ clearing methods. Although all three methods are able to effectively clear the spheroids, we find that SeeDB and ScaleSQ more effectively clear the sample than Clear(T2); however, SeeDB induces green autofluorescence while ScaleS causes sample expansion. Our unique on-chip implementation permits clearing arrays of 3-D cultures using perfusion while monitoring the 3-D cultures throughout the process, enabling visualization of the clearing endpoint as well as monitoring of transient changes that could induce image artefacts. Our microfluidic device is compatible with on-chip 3-D cell culture, permitting the use of on-chip clearing at the endpoint after monitoring the same spheroids during their culture. This on-chip method has the potential to improve readout from 3-D cultures, facilitating their use in cell-based assays for high-content drug screening and other applications. PMID:27493703

  7. ActiveSeismoPick3D - automatic first arrival determination for large active seismic arrays

    NASA Astrophysics Data System (ADS)

    Paffrath, Marcel; Küperkoch, Ludger; Wehling-Benatelli, Sebastian; Friederich, Wolfgang

    2016-04-01

    We developed a tool for automatic determination of first arrivals in active seismic data based on an approach, that utilises higher order statistics (HOS) and the Akaike information criterion (AIC), commonly used in seismology, but not in active seismics. Automatic picking is highly desirable in active seismics as the number of data provided by large seismic arrays rapidly exceeds of what an analyst can evaluate in a reasonable amount of time. To bring the functionality of automatic phase picking into the context of active data, the software package ActiveSeismoPick3D was developed in Python. It uses a modified algorithm for the determination of first arrivals which searches for the HOS maximum in unfiltered data. Additionally, it offers tools for manual quality control and postprocessing, e.g. various visualisation and repicking functionalities. For flexibility, the tool also includes methods for the preparation of geometry information of large seismic arrays and improved interfaces to the Fast Marching Tomography Package (FMTOMO), which can be used for the prediction of travel times and inversion for subsurface properties. Output files are generated in the VTK format, allowing the 3D visualization of e.g. the inversion results. As a test case, a data set consisting of 9216 traces from 64 shots was gathered, recorded at 144 receivers deployed in a regular 2D array of a size of 100 x 100 m. ActiveSeismoPick3D automatically checks the determined first arrivals by a dynamic signal to noise ratio threshold. From the data a 3D model of the subsurface was generated using the export functionality of the package and FMTOMO.

  8. 3D MHD Simulations of Radial Wire Array Z-pinches

    SciTech Connect

    Niasse, N.; Chittenden, J. P.; Bland, S. N.; Suzuki-Vidal, F. A.; Hall, G. N.; Lebedev, S. V.; Calamy, H.; Zucchini, F.; Lassalle, F.; Bedoch, J. P.

    2009-01-21

    Recent experiments carried out on the MAGPIE (1 MA, 250 ns), OEDIPE (730 kA, 1.5 {mu}s) and SPHINX (4 MA, 700 ns)[1] facilities have shown the relatively high level of scalability of the Radial Wire Array Z-pinches. These configurations where the wires stretch radially outwards from a central cathode offer numerous advantages over standard cylindrical arrays. In particular, imploding in a very stable and compact way, they seem suitable for coupling to small scale hohlraums. Making use of the 3D resistive magneto-hydrodynamic code GORGON[2] developed at Imperial College, the dynamic of the radial wire arrays is investigated. Influence of the cathode hotspots and wires angle on the x-ray emissions is also discussed. Comparison with experiments is offered to validate the numerical studies.

  9. 3D MHD Simulations of Radial Wire Array Z-pinches

    NASA Astrophysics Data System (ADS)

    Niasse, N.; Chittenden, J. P.; Bland, S. N.; Suzuki-Vidal, F. A.; Hall, G. N.; Lebedev, S. V.; Calamy, H.; Zucchini, F.; Lassalle, F.; Bedoch, J. P.

    2009-01-01

    Recent experiments carried out on the MAGPIE (1 MA, 250 ns), OEDIPE (730 kA, 1.5 μs) and SPHINX (4 MA, 700 ns)[1] facilities have shown the relatively high level of scalability of the Radial Wire Array Z-pinches. These configurations where the wires stretch radially outwards from a central cathode offer numerous advantages over standard cylindrical arrays. In particular, imploding in a very stable and compact way, they seem suitable for coupling to small scale hohlraums. Making use of the 3D resistive magneto-hydrodynamic code GORGON[2] developed at Imperial College, the dynamic of the radial wire arrays is investigated. Influence of the cathode hotspots and wires angle on the x-ray emissions is also discussed. Comparison with experiments is offered to validate the numerical studies.

  10. 2D and 3D ordered arrays of Co magnetic nanowires

    NASA Astrophysics Data System (ADS)

    Garcia, J.; Prida, V. M.; Vega, V.; Rosa, W. O.; Caballero-Flores, R.; Iglesias, L.; Hernando, B.

    2015-06-01

    Cobalt nanowire arrays spatially distributed in 2D and 3D arrangements have been performed by pulsed electrodeposition into the pores of planar and cylindrical nanoporous anodic alumina membranes, respectively. Morphological characterization points out the good filling factor reached by electroplated Co nanowires in both kinds of alumina membranes exhibiting hexagonally self-ordered porous structures. Co nanowires grown in both kinds of alumina templates exhibit the same crystalline phases. DC magnetometry and First Order Reversal Curve (FORC) analysis were carried out in order to determine the overall magnetic behavior for both nanowire array geometries. It is found that when the Co nanowires of two kinds of arrays are perpendicularly magnetized, both hysteresis loops are identical, suggesting that neither the intrinsic magnetic behavior of the nanowires nor the collective one depend on the arrays geometry. FORC analysis performed along the radial direction of the Co nanowire arrays embedded in the cylindrical alumina template reveals that the contribution of each nanowire to the magnetization reversal process involves its specific orientation with respect to the applied field direction. Furthermore, the comparison between the magnetic properties for both kinds of Co nanowire arrays allows discussing about the effect of the cylindrical geometry of the template on the magnetostatic interaction among nanowires.

  11. Terahertz 3D printed diffractive lens matrices for field-effect transistor detector focal plane arrays.

    PubMed

    Szkudlarek, Krzesimir; Sypek, Maciej; Cywiński, Grzegorz; Suszek, Jarosław; Zagrajek, Przemysław; Feduniewicz-Żmuda, Anna; Yahniuk, Ivan; Yatsunenko, Sergey; Nowakowska-Siwińska, Anna; Coquillat, Dominique; But, Dmytro B; Rachoń, Martyna; Węgrzyńska, Karolina; Skierbiszewski, Czesław; Knap, Wojciech

    2016-09-01

    We present the concept, the fabrication processes and the experimental results for materials and optics that can be used for terahertz field-effect transistor detector focal plane arrays. More specifically, we propose 3D printed arrays of a new type - diffractive multi-zone lenses of which the performance is superior to that of previously used mono-zone diffractive or refractive elements and evaluate them with GaN/AlGaN field-effect transistor terahertz detectors. Experiments performed in the 300-GHz atmospheric window show that the lens arrays offer both a good efficiency and good uniformity, and may improve the signal-to-noise ratio of the terahertz field-effect transistor detectors by more than one order of magnitude. In practice, we tested 3 × 12 lens linear arrays with printed circuit board THz detector arrays used in postal security scanners and observed significant signal-to-noise improvements. Our results clearly show that the proposed technology provides a way to produce cost-effective, reproducible, flat optics for large-size field-effect transistor THz-detector focal plane arrays. PMID:27607620

  12. 2D array transducers for real-time 3D ultrasound guidance of interventional devices

    NASA Astrophysics Data System (ADS)

    Light, Edward D.; Smith, Stephen W.

    2009-02-01

    We describe catheter ring arrays for real-time 3D ultrasound guidance of devices such as vascular grafts, heart valves and vena cava filters. We have constructed several prototypes operating at 5 MHz and consisting of 54 elements using the W.L. Gore & Associates, Inc. micro-miniature ribbon cables. We have recently constructed a new transducer using a braided wiring technology from Precision Interconnect. This transducer consists of 54 elements at 4.8 MHz with pitch of 0.20 mm and typical -6 dB bandwidth of 22%. In all cases, the transducer and wiring assembly were integrated with an 11 French catheter of a Cook Medical deployment device for vena cava filters. Preliminary in vivo and in vitro testing is ongoing including simultaneous 3D ultrasound and x-ray fluoroscopy.

  13. Advanced quadratures and periodic boundary conditions in parallel 3D S{sub n} transport

    SciTech Connect

    Manalo, K.; Yi, C.; Huang, M.; Sjoden, G.

    2013-07-01

    Significant updates in numerical quadratures have warranted investigation with 3D Sn discrete ordinates transport. We show new applications of quadrature departing from level symmetric (S{sub 2}o). investigating 3 recently developed quadratures: Even-Odd (EO), Linear-Discontinuous Finite Element - Surface Area (LDFE-SA), and the non-symmetric Icosahedral Quadrature (IC). We discuss implementation changes to 3D Sn codes (applied to Hybrid MOC-Sn TITAN and 3D parallel PENTRAN) that can be performed to accommodate Icosahedral Quadrature, as this quadrature is not 90-degree rotation invariant. In particular, as demonstrated using PENTRAN, the properties of Icosahedral Quadrature are suitable for trivial application using periodic BCs versus that of reflective BCs. In addition to implementing periodic BCs for 3D Sn PENTRAN, we implemented a technique termed 'angular re-sweep' which properly conditions periodic BCs for outer eigenvalue iterative loop convergence. As demonstrated by two simple transport problems (3-group fixed source and 3-group reflected/periodic eigenvalue pin cell), we remark that all of the quadratures we investigated are generally superior to level symmetric quadrature, with Icosahedral Quadrature performing the most efficiently for problems tested. (authors)

  14. Electrowetting-based adaptive vari-focal liquid lens array for 3D display

    NASA Astrophysics Data System (ADS)

    Won, Yong Hyub

    2014-10-01

    Electrowetting is a phenomenon that can control the surface tension of liquid when a voltage is applied. This paper introduces the fabrication method of liquid lens array by the electrowetting phenomenon. The fabricated 23 by 23 lens array has 1mm diameter size with 1.6 mm interval distance between adjacent lenses. The diopter of each lens was - 24~27 operated at 0V to 50V. The lens array chamber fabricated by Deep Reactive-Ion Etching (DRIE) is deposited with IZO and parylene C and tantalum oxide. To prevent water penetration and achieve high dielectric constant, parylene C and tantalum oxide (ɛ = 23 ~ 25) are used respectively. Hydrophobic surface which enables the range of contact angle from 60 to 160 degree is coated to maximize the effect of electrowetting causing wide band of dioptric power. Liquid is injected into each lens chamber by two different ways. First way was self water-oil dosing that uses cosolvent and diffusion effect, while the second way was micro-syringe by the hydrophobic surface properties. To complete the whole process of the lens array fabrication, underwater sealing was performed using UV adhesive that does not dissolve in water. The transient time for changing from concave to convex lens was measured <33ms (at frequency of 1kHz AC voltage.). The liquid lens array was tested unprecedentedly for integral imaging to achieve more advanced depth information of 3D image.

  15. 3D highly oriented nanoparticulate and microparticulate array ofmetal oxide materials

    SciTech Connect

    Vayssieres, Lionel; Guo, Jinghua; Nordgren, Joseph

    2006-09-15

    Advanced nano and micro particulate thin films of 3d transition and post-transition metal oxides consisting of nanorods and microrods with parallel and perpendicular orientation with respect to the substrate normal, have been successfully grown onto various substrates by heteronucleation, without template and/or surfactant, from the aqueous condensation of solution of metal salts or metal complexes (aqueous chemical growth). Three-dimensional arrays of iron oxide nanorods and zinc oxide nanorods with parallel and perpendicular orientation are presented as well as the oxygen K-edge polarization dependent x-ray absorption spectroscopy (XAS) study of anisotropic perpendicularly oriented microrod array of ZnO performed at synchrotron radiation source facility.

  16. 3-D periodic mesoporous nickel oxide for nonenzymatic uric acid sensors with improved sensitivity

    NASA Astrophysics Data System (ADS)

    Huang, Wei; Cao, Yang; Chen, Yong; Zhou, Yang; Huang, Qingyou

    2015-12-01

    3-D periodic mesoporous nickel oxide (NiO) particles with crystalline walls have been synthesized through the microwave-assisted hard template route toward the KIT-6 silica. It was investigated as a nonenzymatic amperometric sensor for the detection of uric acid. 3-D periodic nickel oxide matrix has been obtained by the hard template route from the KIT-6 silica template. The crystalline nickel oxide belonged to the Ia3d space group, and its structure was characterized by X-ray diffraction (XRD), N2 adsorption-desorption, and transmission electron microscopy (TEM). The analysis results showed that the microwave-assisted mesoporous NiO materials were more appropriate to be electrochemical sensors than the traditional mesoporous NiO. Cyclic voltammetry (CV) revealed that 3-D periodic NiO exhibited a direct electrocatalytic activity for the oxidation of uric acid in sodium hydroxide solution. The enzyme-less amperometric sensor used in the detection of uric acid with detection limit of 0.005 μM (S/N = 3) over wide linear detection ranges up to 0.374 mM and with a high sensitivity of 756.26 μA mM-1 cm-2, and a possible mechanism was also given in the paper.

  17. Interdroplet bilayer arrays in millifluidic droplet traps from 3D-printed moulds.

    PubMed

    King, Philip H; Jones, Gareth; Morgan, Hywel; de Planque, Maurits R R; Zauner, Klaus-Peter

    2014-02-21

    In droplet microfluidics, aqueous droplets are typically separated by an oil phase to ensure containment of molecules in individual droplets of nano-to-picoliter volume. An interesting variation of this method involves bringing two phospholipid-coated droplets into contact to form a lipid bilayer in-between the droplets. These interdroplet bilayers, created by manual pipetting of microliter droplets, have proved advantageous for the study of membrane transport phenomena, including ion channel electrophysiology. In this study, we adapted the droplet microfluidics methodology to achieve automated formation of interdroplet lipid bilayer arrays. We developed a 'millifluidic' chip for microliter droplet generation and droplet packing, which is cast from a 3D-printed mould. Droplets of 0.7-6.0 μL volume were packed as homogeneous or heterogeneous linear arrays of 2-9 droplets that were stable for at least six hours. The interdroplet bilayers had an area of up to 0.56 mm(2), or an equivalent diameter of up to 850 μm, as determined from capacitance measurements. We observed osmotic water transfer over the bilayers as well as sequential bilayer lysis by the pore-forming toxin melittin. These millifluidic interdroplet bilayer arrays combine the ease of electrical and optical access of manually pipetted microdroplets with the automation and reproducibility of microfluidic technologies. Moreover, the 3D-printing based fabrication strategy enables the rapid implementation of alternative channel geometries, e.g. branched arrays, with a design-to-device time of just 24-48 hours. PMID:24336841

  18. 3D imaging and characterization of microlenses and microlens arrays using nonlinear microscopy

    NASA Astrophysics Data System (ADS)

    Krmpot, Aleksandar J.; Tserevelakis, George J.; Murić, Branka D.; Filippidis, George; Pantelić, Dejan V.

    2013-05-01

    In this work, nonlinear laser scanning microscopy was employed for the characterization and three-dimensional (3D) imaging of microlenses and microlens arrays. Third-harmonic generation and two-photon excitation fluorescence (TPEF) signals were recorded and the obtained data were further processed in order to generate 3D reconstructions of the examined samples. Femtosecond laser pulses (1028 nm) were utilized for excitation. Microlenses were manufactured on Tot'hema and eosin sensitized gelatin layers using a green (532 nm) continuous wave laser beam using the direct laser writing method. The profiles of the microlens surface were obtained from the radial cross-sections, using a triple-Gaussian fit. The analytical shapes of the profiles were also used for ray tracing. Furthermore, the volumes of the microlenses were determined with high precision. The TPEF signal arising from the volume of the material was recorded and the respective 3D spatial fluorescence distribution of the samples was mapped. Nonlinear microscopy modalities have been shown to be a powerful diagnostic tool for microlens characterization as they enable in-depth investigations of the structural properties of the samples, in a nondestructive manner.

  19. Array tomography: characterizing FAC-sorted populations of zebrafish immune cells by their 3D ultrastructure

    PubMed Central

    Wacker, Irene; Chockley, Peter; Bartels, Carolin; Spomer, Waldemar; Hofmann, Andreas; Gengenbach, Ulrich; Singh, Sachin; Thaler, Marlene; Grabher, Clemens; SCHRÖDER, RASMUS R

    2015-01-01

    For 3D reconstructions of whole immune cells from zebrafish, isolated from adult animals by FAC-sorting we employed array tomography on hundreds of serial sections deposited on silicon wafers. Image stacks were either recorded manually or automatically with the newly released ZEISS Atlas 5 Array Tomography platform on a Zeiss FEGSEM. To characterize different populations of immune cells, organelle inventories were created by segmenting individual cells. In addition, arrays were used for quantification of cell populations with respect to the various cell types they contained. The detection of immunological synapses in cocultures of cell populations from thymus or WKM with cancer cells helped to identify the cytotoxic nature of these cells. Our results demonstrate the practicality and benefit of AT for high-throughput ultrastructural imaging of substantial volumes. Lay Description To look at immune cells from zebrafish we employed array tomography, a technique where arrays of serial sections deposited on solid substrates are used for imaging. Cell populations were isolated from the different organs of zebrafish involved in haematopoiesis, the production of blood cells. They were chemically fixed and centrifuged to concentrate them in a pellet that was then dehydrated and embedded in resin. Using a custom-built handling device it was possible to place hundreds of serial sections on silicon wafers as well ordered arrays. To image a whole cell at a resolution that would allow identifying all the organelles (i.e. compartments surrounded by membranes) inside the cell, stacks of usually 50–100 images were recorded in a scanning electron microscope (SEM). This recording was either done manually or automatically using the newly released Atlas Array Tomography platform on a ZEISS SEM. For the imaging of the sections a pixel size of about 5 nm was chosen, which defines membrane boundaries very well and allows segmentation of the membrane topology. After alignment of the

  20. 2-D array for 3-D Ultrasound Imaging Using Synthetic Aperture Techniques

    PubMed Central

    Daher, Nadim M.; Yen, Jesse T.

    2010-01-01

    A 2-D array of 256 × 256 = 65,536 elements, with total area 4 × 4 = 16 cm2, serves as a flexible platform for developing acquisition schemes for 3-D rectilinear ultrasound imaging at 10 MHz using synthetic aperture techniques. This innovative system combines a simplified interconnect scheme and synthetic aperture techniques with a 2-D array for 3-D imaging. A row-column addressing scheme is used to access different elements for different transmit events. This addressing scheme is achieved through a simple interconnect, consisting of one top, one bottom single layer flex circuits, which, compared to multi-layer flex circuits, are simpler to design, cheaper to manufacture and thinner so their effect on the acoustic response is minimized. We present three designs that prioritize different design objectives: volume acquisiton time, resolution, and sensitivity, while maintaining acceptable figures for the other design objectives. For example, one design overlooks time acquisition requirements, assumes good noise conditions, and optimizes for resolution, achieving −6 dB and −20 dB beamwidths of less than 0.2 and 0.5 millimeters, respectively, for an F/2 aperture. Another design can acquire an entire volume in 256 transmit events, with −6dB and −20 dB beamwidths in the order of 0.4 and 0.8 millimeters, respectively. PMID:16764446

  1. Application of a 3d Smart Flexible Phased-Array to Piping Inspection

    NASA Astrophysics Data System (ADS)

    Toullelan, G.; Casula, O.; Abittan, E.; Dumas, P.

    2008-02-01

    The piping inspection in nuclear power plants is mainly performed in contact with ultrasonic wedge transducers. During the scanning, the fixed shape of the wedges cannot conform to the irregular surfaces and complex geometries of the components (butt weld, nozzle, elbow). The surface irregularities lead to thickness variations of the coupling medium that result in beam distortions and losses of sensitivity. A 3-D ultrasonic flexible phased-array is presented here and applied to the ultrasonic inspection of a welded pipe. This example of a complex geometry inspection is typical of the field of application for such sensor. The phased-array probe is flexible to conform to a complex profile and to minimize the thickness of the coupling layer. The independent piezoelectric elements composing the radiating surface are mechanically assembled to build an articulated structure. A profilometer, embedded in the transducer, measures the local surface distortion allowing to compute in real-time the optimized delay laws and to compensate the distortions of the 2D or 3D profiles. Those delay laws transferred to the UT-acquisition system are applied in real-time to the piezoelectric elements. The experiments presented here aim to determine the detection abilities of this technique using multi-shot configurations (e.g. angular scanning, several points focusing).

  2. Fabrication of 3-D Reconstituted Organoid Arrays by DNA-Programmed Assembly of Cells (DPAC).

    PubMed

    Todhunter, Michael E; Weber, Robert J; Farlow, Justin; Jee, Noel Y; Cerchiari, Alec E; Gartner, Zev J

    2016-01-01

    Tissues are the organizational units of function in metazoan organisms. Tissues comprise an assortment of cellular building blocks, soluble factors, and extracellular matrix (ECM) composed into specific three-dimensional (3-D) structures. The capacity to reconstitute tissues in vitro with the structural complexity observed in vivo is key to understanding processes such as morphogenesis, homeostasis, and disease. In this article, we describe DNA-programmed assembly of cells (DPAC), a method to fabricate viable, functional arrays of organoid-like tissues within 3-D ECM gels. In DPAC, dissociated cells are chemically functionalized with degradable oligonucleotide "Velcro," allowing rapid, specific, and reversible cell adhesion to a two-dimensional (2-D) template patterned with complementary DNA. An iterative assembly process builds up organoids, layer-by-layer, from this initial 2-D template and into the third dimension. Cleavage of the DNA releases the completed array of tissues that are captured and fully embedded in ECM gels for culture and observation. DPAC controls the size, shape, composition, and spatial heterogeneity of organoids and permits positioning of constituent cells with single-cell resolution even within cultures several centimeters long. © 2016 by John Wiley & Sons, Inc. PMID:27622567

  3. The `L' Array, a method to model 3D Electrical Resistivity Tomography (ERT) data

    NASA Astrophysics Data System (ADS)

    Chavez Segura, R. E.; Chavez-Hernandez, G.; Delgado, C.; Tejero-Andrade, A.

    2010-12-01

    The electrical resistivity tomography (ERT) is a method designed to calculate the distribution of apparent electrical resistivities in the subsoil by means of a great number of observations with the aim of determining an electrical image displaying the distribution of true resistivities in the subsoil. Such process can be carried out to define 2D or 3D models of the subsurface. For a 3D ERT, usually, the electrodes are placed in a squared grid keeping the distance between adjacent electrodes constant in the x and y directions. Another design employed, consists of a series of parallel lines whose space inter-lines must be smaller or equal to four times the electrode separation. The most common electrode arrays frequently employed for this type of studies are the pole-pole, pole-dipole and dipole-dipole. Unfortunately, ERT surface sampling schemes are limited by physical conditions or obstacles, like buildings, highly populated urban zones, and geologic/topographic features, where the lines of electrodes cannot be set. However, it is always necessary to characterize the subsoil beneath such anthropogenic or natural features. The ‘L’ shaped array has the main purpose to overcome such difficulties by surrounding the study area with a square of electrode lines. The measurements are obtained by switching automatically current and potential electrodes from one line to the other. Each observation adds a level of information, from one profile to the other. Once the total levels of data are completed, the opposite ‘L’ array can be measured following the same process. The complete square is computed after the parallel profiles are observed as well. At the end, the computed resistivities are combined to form a 3D matrix of observations. Such set of data can be inverted to obtain the true resistivity distribution at depth in the form of a working cube, which can be interpreted. The method was tested with theoretical models, which included a set of two resistive cubes

  4. UV photodetectors based on 3D periodic Au-decorated nanocone ZnO films.

    PubMed

    Fan, Haowen; Sun, Mengwei; Ma, Pengsha; Yin, Min; Lu, Linfeng; Xue, Xinzhong; Zhu, Xufei; Li, Dongdong; Ma, Jing

    2016-09-01

    Thermal nanoimprinting technology was employed to fabricate 3D periodic nanocone ZnO films with different height/pitch values for photodetectors to optimize their light capturing property. The photocurrents of patterned film photodetectors increase with the height/pitch values. The patterned ZnO-Au hybrid film further boosts the ultraviolet (UV) response. Due to the co-contribution of the light trapping of 3D periodic structures and the driving force of the Schottky barrier in the Au/ZnO interface, the patterned ZnO-Au hybrid films with height/pitch of 40 nm/866 nm exhibit the best UV photoresponse (I on/I off = 779.927), which is 3.8 times higher than its film counterpart (I on/I off = 164.1). PMID:27482636

  5. UV photodetectors based on 3D periodic Au-decorated nanocone ZnO films

    NASA Astrophysics Data System (ADS)

    Fan, Haowen; Sun, Mengwei; Ma, Pengsha; Yin, Min; Lu, Linfeng; Xue, Xinzhong; Zhu, Xufei; Li, Dongdong; Ma, Jing

    2016-09-01

    Thermal nanoimprinting technology was employed to fabricate 3D periodic nanocone ZnO films with different height/pitch values for photodetectors to optimize their light capturing property. The photocurrents of patterned film photodetectors increase with the height/pitch values. The patterned ZnO–Au hybrid film further boosts the ultraviolet (UV) response. Due to the co-contribution of the light trapping of 3D periodic structures and the driving force of the Schottky barrier in the Au/ZnO interface, the patterned ZnO–Au hybrid films with height/pitch of 40 nm/866 nm exhibit the best UV photoresponse (I on/I off = 779.927), which is 3.8 times higher than its film counterpart (I on/I off = 164.1).

  6. Two-dimensional angular filter array for angular domain imaging with 3D printed angular filters

    NASA Astrophysics Data System (ADS)

    Ng, Eldon; Carson, Jeffrey J. L.

    2013-02-01

    Angular Domain Imaging (ADI) is a technique that is capable of generating two dimensional shadowgrams of attenuating targets embedded in a scattering medium. In ADI, an angular filter array (AFA) is positioned between the sample and the detector to distinguish between quasi-ballistic photons and scattered photons. An AFA is a series of micro-channels with a high aspect ratio. Previous AFAs from our group were constructed by micro-machining the micro-channels into a silicon wafer, limiting the imaging area to a one dimensional line. Two dimensional images were acquired via scanning. The objective of this work was to extend the AFA design to two dimensions to allow for two dimensional imaging with minimal scanning. The second objective of this work was to perform an initial characterization of the imaging capabilities of the 2D AFA. Our approach was to use rapid 3D prototyping techniques to generate an array of micro-channels. The imaging capabilities were then evaluated by imaging a 0.9 mm graphite rod submerged in a scattering media. Contrast was observed to improve when a second angular filter array was placed in front of the sample to mask the incoming light.

  7. Simple tools for simulating phased array focal laws on 3D solids

    NASA Astrophysics Data System (ADS)

    Weber, Walter H.; Mair, H. Douglas; Frazer, Leigh

    2001-04-01

    This paper reports our progress on the development of a three-dimensional raytracing program that can simulate the focal laws of a phased array system. The modeled transducer is divided into elements of a given length, width and inter-element gap distance. Each focal law to be modeled requires a steering angle, focal length and selection of which groups of elements are transmitting and receiving. Electronic scanning is simulated by stepping through a series of predefined focal laws. The program phase shifts and sums the received rays at each element based on the properties of the currently-active focal law. Simulated A-scans are constructed from the received rays which appear animated as the beam is swept. Beam profiles can also be generated that show the primary forward beam and energy in the side lobes. The work is based on Imagine3D ultrasonic simulation software and the dedicated efforts of Doug Mair and Leigh Frazer.

  8. Thermal impact of an active 3-D microelectrode array implanted in the brain.

    PubMed

    Kim, Sohee; Tathireddy, Prashant; Normann, Richard A; Solzbacher, Florian

    2007-12-01

    A chronically implantable, wireless neural interface device will require integrating electronic circuitry with the interfacing microelectrodes in order to eliminate wired connections. Since the integrated circuit (IC) dissipates a certain amount of power, it will raise the temperature in surrounding tissues where it is implanted. In this paper, the thermal influence of the integrated 3-D Utah electrode array (UEA) device implanted in the brain was investigated by numerical simulation using finite element analysis (FEA) and by experimental measurement in vitro as well as in vivo. The numerically calculated and experimentally measured temperature increases due to the UEA implantation were in good agreement. The experimentally validated numerical model predicted that the temperature increases linearly with power dissipation through the UEA, with a slope of 0.029 degree C/mW over the power dissipation levels expected to be used. The influences of blood perfusion, brain metabolism, and UEA geometry on tissue heating were also investigated using the numerical model. PMID:18198706

  9. CMOS array of photodiodes with electronic processing for 3D optical reconstruction

    NASA Astrophysics Data System (ADS)

    Hornero, Gemma; Montane, Enric; Chapinal, Genis; Moreno, Mauricio; Herms, Atila

    2001-04-01

    It is well known that laser time-of-flight (TOF) and optical triangulation are the most useful optical techniques for distance measurements. The first one is more suitable for large distances, since for short range of distances high modulation frequencies of laser diodes (©200-500MHz) are needed. For these ranges, optical triangulation is simpler, as it is only necessary to read the projection of the laser point over a linear optical sensor without any laser modulation. Laser triangulation is based on the rotation of the object. This motion shifts the projected point over the linear sensor, resulting on 3D information, by means of the whole readout of the linear sensor in each angle position. On the other hand, a hybrid method of triangulation and TOF can be implemented. In this case, a synchronized scanning of a laser beam over the object results in different arrival times of light to each pixel. The 3D information is carried by these delays. Only a single readout of the linear sensor is needed. In this work we present the design of two different linear arrays of photodiodes in CMOS technology, the first one based on the Optical triangulation measurement and the second one based in this hybrid method (TFO). In contrast to PSD (Position Sensitive Device) and CCDs, CMOS technology can include, on the same chip, photodiodes, control and processing electronics, that in the other cases should be implemented with external microcontrollers.

  10. Sensitivity Tuning through Additive Heterogeneous Plasmon Coupling between 3D Assembled Plasmonic Nanoparticle and Nanocup Arrays.

    PubMed

    Seo, Sujin; Zhou, Xiangfei; Liu, Gang Logan

    2016-07-01

    Plasmonic substrates have fixed sensitivity once the geometry of the structure is defined. In order to improve the sensitivity, significant research effort has been focused on designing new plasmonic structures, which involves high fabrication costs; however, a method is reported for improving sensitivity not by redesigning the structure but by simply assembling plasmonic nanoparticles (NPs) near the evanescent field of the underlying 3D plasmonic nanostructure. Here, a nanoscale Lycurgus cup array (nanoLCA) is employed as a base colorimetric plasmonic substrate and an assembly template. Compared to the nanoLCA, the NP assembled nanoLCA (NP-nanoLCA) exhibits much higher sensitivity for both bulk refractive index sensing and biotin-streptavidin binding detection. The limit of detection of the NP-nanoLCA is at least ten times smaller when detecting biotin-streptavidin conjugation. The numerical calculations confirm the importance of the additive plasmon coupling between the NPs and the nanoLCA for a denser and stronger electric field in the same 3D volumetric space. Tunable sensitivity is accomplished by controlling the number of NPs in each nanocup, or the number density of the hot spots. This simple yet scalable and cost-effective method of using additive heterogeneous plasmon coupling effects will benefit various chemical, medical, and environmental plasmon-based sensors. PMID:27206214

  11. A preliminary evaluation work on a 3D ultrasound imaging system for 2D array transducer

    NASA Astrophysics Data System (ADS)

    Zhong, Xiaoli; Li, Xu; Yang, Jiali; Li, Chunyu; Song, Junjie; Ding, Mingyue; Yuchi, Ming

    2016-04-01

    This paper presents a preliminary evaluation work on a pre-designed 3-D ultrasound imaging system. The system mainly consists of four parts, a 7.5MHz, 24×24 2-D array transducer, the transmit/receive circuit, power supply, data acquisition and real-time imaging module. The row-column addressing scheme is adopted for the transducer fabrication, which greatly reduces the number of active channels . The element area of the transducer is 4.6mm by 4.6mm. Four kinds of tests were carried out to evaluate the imaging performance, including the penetration depth range, axial and lateral resolution, positioning accuracy and 3-D imaging frame rate. Several strong reflection metal objects , fixed in a water tank, were selected for the purpose of imaging due to a low signal-to-noise ratio of the transducer. The distance between the transducer and the tested objects , the thickness of aluminum, and the seam width of the aluminum sheet were measured by a calibrated micrometer to evaluate the penetration depth, the axial and lateral resolution, respectively. The experiment al results showed that the imaging penetration depth range was from 1.0cm to 6.2cm, the axial and lateral resolution were 0.32mm and 1.37mm respectively, the imaging speed was up to 27 frames per second and the positioning accuracy was 9.2%.

  12. Real-time tracking with a 3D-Flow processor array

    SciTech Connect

    Crosetto, D.

    1993-06-01

    The problem of real-time track-finding has been performed to date with CAM (Content Addressable Memories) or with fast coincidence logic, because the processing scheme was thought to have much slower performance. Advances in technology together with a new architectural approach make it feasible to also explore the computing technique for real-time track finding thus giving the advantages of implementing algorithms that can find more parameters such as calculate the sagitta, curvature, pt, etc., with respect to the CAM approach. The report describes real-time track finding using new computing approach technique based on the 3D-Flow array processor system. This system consists of a fixed interconnection architecture scheme, allowing flexible algorithm implementation on a scalable platform. The 3D-Flow parallel processing system for track finding is scalable in size and performance by either increasing the number of processors, or increasing the speed or else the number of pipelined stages. The present article describes the conceptual idea and the design stage of the project.

  13. Comparison of 3-D synthetic aperture phased-array ultrasound imaging and parallel beamforming.

    PubMed

    Rasmussen, Morten Fischer; Jensen, Jørgen Arendt

    2014-10-01

    This paper demonstrates that synthetic aperture imaging (SAI) can be used to achieve real-time 3-D ultrasound phased-array imaging. It investigates whether SAI increases the image quality compared with the parallel beamforming (PB) technique for real-time 3-D imaging. Data are obtained using both simulations and measurements with an ultrasound research scanner and a commercially available 3.5- MHz 1024-element 2-D transducer array. To limit the probe cable thickness, 256 active elements are used in transmit and receive for both techniques. The two imaging techniques were designed for cardiac imaging, which requires sequences designed for imaging down to 15 cm of depth and a frame rate of at least 20 Hz. The imaging quality of the two techniques is investigated through simulations as a function of depth and angle. SAI improved the full-width at half-maximum (FWHM) at low steering angles by 35%, and the 20-dB cystic resolution by up to 62%. The FWHM of the measured line spread function (LSF) at 80 mm depth showed a difference of 20% in favor of SAI. SAI reduced the cyst radius at 60 mm depth by 39% in measurements. SAI improved the contrast-to-noise ratio measured on anechoic cysts embedded in a tissue-mimicking material by 29% at 70 mm depth. The estimated penetration depth on the same tissue-mimicking phantom shows that SAI increased the penetration by 24% compared with PB. Neither SAI nor PB achieved the design goal of 15 cm penetration depth. This is likely due to the limited transducer surface area and a low SNR of the experimental scanner used. PMID:25265174

  14. 3D carbon/cobalt-nickel mixed-oxide hybrid nanostructured arrays for asymmetric supercapacitors.

    PubMed

    Zhu, Jianhui; Jiang, Jian; Sun, Zhipeng; Luo, Jingshan; Fan, Zhanxi; Huang, Xintang; Zhang, Hua; Yu, Ting

    2014-07-23

    The electrochemical performance of supercapacitors relies not only on the exploitation of high-capacity active materials, but also on the rational design of superior electrode architectures. Herein, a novel supercapacitor electrode comprising 3D hierarchical mixed-oxide nanostructured arrays (NAs) of C/CoNi3 O4 is reported. The network-like C/CoNi3 O4 NAs exhibit a relatively high specific surface area; it is fabricated from ultra-robust Co-Ni hydroxide carbonate precursors through glucose-coating and calcination processes. Thanks to their interconnected three-dimensionally arrayed architecture and mesoporous nature, the C/CoNi3 O4 NA electrode exhibits a large specific capacitance of 1299 F/g and a superior rate performance, demonstrating 78% capacity retention even when the discharge current jumps by 100 times. An optimized asymmetric supercapacitor with the C/CoNi3 O4 NAs as the positive electrode is fabricated. This asymmetric supercapacitor can reversibly cycle at a high potential of 1.8 V, showing excellent cycling durability and also enabling a remarkable power density of ∼13 kW/kg with a high energy density of ∼19.2 W·h/kg. Two such supercapacitors linked in series can simultaneously power four distinct light-emitting diode indicators; they can also drive the motor of remote-controlled model planes. This work not only presents the potential of C/CoNi3 O4 NAs in thin-film supercapacitor applications, but it also demonstrates the superiority of electrodes with such a 3D hierarchical architecture. PMID:24643977

  15. 3-D Autojuggie: Automating Deployment of Two-Dimensional Geophone Arrays for Efficient Ultra-Shallow Seismic-Reflection Surveys

    NASA Astrophysics Data System (ADS)

    Tsoflias, G. P.; Steeples, D. W.; Czarnecki, G.; Sloan, S. D.; Eslick, R.

    2005-12-01

    Near-surface seismic reflection methods require dense spatial sampling of the wavefield. Seismic surveys imaging the top ten meters of the subsurface employ geophone spacing on the order of decimeters. Two-dimensional (2-D), ultra-shallow seismic reflection methods have increased in popularity. However, placement of geophones remains a labor-intensive deterrent to the acquisition of near-surface, 3-D seismic data. Although 3-D seismic imaging is a mature hydrocarbon-exploration technique, only a handful of 3-D shallow seismic surveys have been acquired over the last decade. We present the development and field-testing of instrumentation for automatic deployment of a 2-D array of 72 geophones for acquisition of ultra-shallow 3-D reflection seismic data, referred to as the 3-D Autojuggie. The main components of the instrumentation include: a) two vertically stacked rigid steel frames used for positioning, planting, and transporting an array of geophones; b) an hydraulically controlled mechanism for decoupling the geophones from the steel frames during seismic data recording; and c) a 2-D array of seventy-two 100 Hz Mark Products geophones with 20.32 cm long spikes, spaced 20 cm apart in the inline (12 geophones) and crossline (6 rows) orientation. Seismic noise testing (walkaways) conducted at The University of Kansas employing automatically planted 2-D geophone arrays next to conventional hand-planted geophones resulted in equivalent seismic imaging of the subsurface. The geophone planting instrumentation did not degrade the quality of the recorded wavefield. The efficiency of automatically placing a dense 2-D array of geophones on the ground and the ease of moving the array quickly to adjacent positions, along with the ability to acquire comparable quality data to conventional hand-planted geophones, indicate that the 3-D Autojuggie is a viable approach to ultra-shallow 3-D seismic acquisition. Conceptually, the design could accommodate an array of hundreds of

  16. Cell interaction study method using novel 3D silica nanoneedle gradient arrays

    PubMed Central

    Rajput, Deepak; Crowder, Spencer; Hofmeister, Lucas; Costa, Lino; Sung, Hak-Joon; Hofmeister, William

    2012-01-01

    Understanding cellular interactions with culture substrate features is important to advance cell biology and regenerative medicine. When surface topographical features are considerably larger in vertical dimension and are spaced at least one cell dimension apart, the features act as 3D physical barriers that can guide cell adhesion, thereby altering cell behavior. In the present study, we investigated competitive interactions of cells with neighboring cells and matrix using a novel nanoneedle gradient array. A gradient array of nanoholes was patterned at the surface of fused silica by single-pulse femtosecond laser machining. A negative replica of the pattern was extracted by nanoimprinting with a thin film of polymer. Silica was deposited on top of the polymer replica to form silica nanoneedles. NIH 3T3 fibroblasts were cultured on silica nanoneedles and their behavior was studied and compared with those cultured on a flat silica surface. The presence of silica nanoneedles was found to enhance the adhesion of fibroblasts while maintaining cell viability. The anisotropy in the arrangement of silica nanoneedles was found to affect the morphology and spreading of fibroblasts. Additionally, variations in nanoneedle spacing regulated cell-matrix and cell-cell interactions, effectively preventing cell aggregation in areas of tightly-packed nanoneedles. This proof-of-concept study provides a reproducible means for controlling competitive cell adhesion events and offers a novel system whose properties can be manipulated to intimately control cell behavior. PMID:23006558

  17. Amperometric biosensor based on 3D ordered freestanding porous Pt nanowire array electrode.

    PubMed

    Wang, Yunli; Zhu, Yingchun; Chen, Jingjing; Zeng, Yi

    2012-09-28

    A three-dimensionally (3D) ordered freestanding porous platinum (Pt) nanowire array electrode (PPNWAE) with pores of several nanometers in size and a Pt nanowire array electrode (PNWAE) without pores were facilely fabricated by metal electrodeposition and direct integration with a Pt disk electrode. The unusual PPNWAE with high active area showed excellent sensitivity (0.36 mA cm(-2) mM(-1)) and a wide detection range (4.5 μM-27.1 mM) to hydrogen peroxide (H(2)O(2)). A glucose oxidase (GOD)-based biosensor (PPNWAE/GOD) with a considerably wide detection range (4.5 μM-189.5 mM) to glucose was demonstrated. Furthermore, a lower detection limit, higher sensitivity and smaller value of Michaelis-Menten constant k(m) were recorded for PPNWAE-based biosensors compared with PNWAE-based biosensors. Particularly, the response current to glucose of PPNWAE/GOD was ca. 100% higher than that of PNWAE/GOD and the response current to H(2)O(2) of PPNWAE was ca. 50% higher than that of PNWAE, owing to the granular and rougher porous nanowire surface enabling greater bioactivity for GOD. The selectivity of PPNWAE/GOD glucose biosensor was also estimated. PMID:22898987

  18. Design and implementation of Gm-APD array readout integrated circuit for infrared 3D imaging

    NASA Astrophysics Data System (ADS)

    Zheng, Li-xia; Yang, Jun-hao; Liu, Zhao; Dong, Huai-peng; Wu, Jin; Sun, Wei-feng

    2013-09-01

    A single-photon detecting array of readout integrated circuit (ROIC) capable of infrared 3D imaging by photon detection and time-of-flight measurement is presented in this paper. The InGaAs avalanche photon diodes (APD) dynamic biased under Geiger operation mode by gate controlled active quenching circuit (AQC) are used here. The time-of-flight is accurately measured by a high accurate time-to-digital converter (TDC) integrated in the ROIC. For 3D imaging, frame rate controlling technique is utilized to the pixel's detection, so that the APD related to each pixel should be controlled by individual AQC to sense and quench the avalanche current, providing a digital CMOS-compatible voltage pulse. After each first sense, the detector is reset to wait for next frame operation. We employ counters of a two-segmental coarse-fine architecture, where the coarse conversion is achieved by a 10-bit pseudo-random linear feedback shift register (LFSR) in each pixel and a 3-bit fine conversion is realized by a ring delay line shared by all pixels. The reference clock driving the LFSR counter can be generated within the ring delay line Oscillator or provided by an external clock source. The circuit is designed and implemented by CSMC 0.5μm standard CMOS technology and the total chip area is around 2mm×2mm for 8×8 format ROIC with 150μm pixel pitch. The simulation results indicate that the relative time resolution of the proposed ROIC can achieve less than 1ns, and the preliminary test results show that the circuit function is correct.

  19. High linearity SPAD and TDC array for TCSPC and 3D ranging applications

    NASA Astrophysics Data System (ADS)

    Villa, Federica; Lussana, Rudi; Bronzi, Danilo; Dalla Mora, Alberto; Contini, Davide; Tisa, Simone; Tosi, Alberto; Zappa, Franco

    2015-01-01

    An array of 32x32 Single-Photon Avalanche-Diodes (SPADs) and Time-to-Digital Converters (TDCs) has been fabricated in a 0.35 μm automotive-certified CMOS technology. The overall dimension of the chip is 9x9 mm2. Each pixel is able to detect photons in the 300 nm - 900 nm wavelength range with a fill-factor of 3.14% and either to count them or to time stamp their arrival time. In photon-counting mode an in-pixel 6-bit counter provides photon-numberresolved intensity movies at 100 kfps, whereas in photon-timing mode the 10-bit in-pixel TDC provides time-resolved maps (Time-Correlated Single-Photon Counting measurements) or 3D depth-resolved (through direct time-of-flight technique) images and movies, with 312 ps resolution. The photodetector is a 30 μm diameter SPAD with low Dark Count Rate (120 cps at room temperature, 3% hot-pixels) and 55% peak Photon Detection Efficiency (PDE) at 450 nm. The TDC has a 6-bit counter and a 4-bit fine interpolator, based on a Delay Locked Loop (DLL) line, which makes the TDC insensitive to process, voltage, and temperature drifts. The implemented sliding-scale technique improves linearity, giving 2% LSB DNL and 10% LSB INL. The single-shot precision is 260 ps rms, comprising SPAD, TDC and driving board jitter. Both optical and electrical crosstalk among SPADs and TDCs are negligible. 2D fast movies and 3D reconstructions with centimeter resolution are reported.

  20. XUV spectra of 2nd transition row elements: identification of 3d-4p and 3d-4f transition arrays

    NASA Astrophysics Data System (ADS)

    Lokasani, Ragava; Long, Elaine; Maguire, Oisin; Sheridan, Paul; Hayden, Patrick; O'Reilly, Fergal; Dunne, Padraig; Sokell, Emma; Endo, Akira; Limpouch, Jiri; O'Sullivan, Gerry

    2015-12-01

    The use of laser produced plasmas (LPPs) in extreme ultraviolet/soft x-ray lithography and metrology at 13.5 nm has been widely reported and recent research efforts have focused on developing next generation sources for lithography, surface morphology, patterning and microscopy at shorter wavelengths. In this paper, the spectra emitted from LPPs of the 2nd transition row elements from yttrium (Z = 39) to palladium (Z = 46), with the exception of zirconium (Z = 40) and technetium (Z = 43), produced by two Nd:YAG lasers which delivered up to 600 mJ in 7 ns and 230 mJ in 170 ps, respectively, are reported. Intense emission was observed in the 2-8 nm spectral region resulting from unresolved transition arrays (UTAs) due to 3d-4p, 3d-4f and 3p-3d transitions. These transitions in a number of ion stages of yttrium, niobium, ruthenium and rhodium were identified by comparison with results from Cowan code calculations and previous studies. The theoretical data were parameterized using the UTA formalism and the mean wavelength and widths were calculated and compared with experimental results.

  1. Technical Note: Rapid prototyping of 3D grid arrays for image guided therapy quality assurance

    SciTech Connect

    Kittle, David; Holshouser, Barbara; Slater, James M.; Guenther, Bob D.; Pitsianis, Nikos P.; Pearlstein, Robert D.

    2008-12-15

    Three dimensional grid phantoms offer a number of advantages for measuring imaging related spatial inaccuracies for image guided surgery and radiotherapy. The authors examined the use of rapid prototyping technology for directly fabricating 3D grid phantoms from CAD drawings. We tested three different fabrication process materials, photopolymer jet with acrylic resin (PJ/AR), selective laser sintering with polyamide (SLS/P), and fused deposition modeling with acrylonitrile butadiene styrene (FDM/ABS). The test objects consisted of rectangular arrays of control points formed by the intersections of posts and struts (2 mm rectangular cross section) and spaced 8 mm apart in the x, y, and z directions. The PJ/AR phantom expanded after immersion in water which resulted in permanent warping of the structure. The surface of the FDM/ABS grid exhibited a regular pattern of depressions and ridges from the extrusion process. SLS/P showed the best combination of build accuracy, surface finish, and stability. Based on these findings, a grid phantom for assessing machine-dependent and frame-induced MR spatial distortions was fabricated to be used for quality assurance in stereotactic neurosurgical and radiotherapy procedures. The spatial uniformity of the SLS/P grid control point array was determined by CT imaging (0.6x0.6x0.625 mm{sup 3} resolution) and found suitable for the application, with over 97.5% of the control points located within 0.3 mm of the position specified in CAD drawing and none of the points off by more than 0.4 mm. Rapid prototyping is a flexible and cost effective alternative for development of customized grid phantoms for medical physics quality assurance.

  2. Simulated and Real Sheet-of-Light 3D Object Scanning Using a-Si:H Thin Film PSD Arrays

    PubMed Central

    Contreras, Javier; Tornero, Josep; Ferreira, Isabel; Martins, Rodrigo; Gomes, Luis; Fortunato, Elvira

    2015-01-01

    A MATLAB/SIMULINK software simulation model (structure and component blocks) has been constructed in order to view and analyze the potential of the PSD (Position Sensitive Detector) array concept technology before it is further expanded or developed. This simulation allows changing most of its parameters, such as the number of elements in the PSD array, the direction of vision, the viewing/scanning angle, the object rotation, translation, sample/scan/simulation time, etc. In addition, results show for the first time the possibility of scanning an object in 3D when using an a-Si:H thin film 128 PSD array sensor and hardware/software system. Moreover, this sensor technology is able to perform these scans and render 3D objects at high speeds and high resolutions when using a sheet-of-light laser within a triangulation platform. As shown by the simulation, a substantial enhancement in 3D object profile image quality and realism can be achieved by increasing the number of elements of the PSD array sensor as well as by achieving an optimal position response from the sensor since clearly the definition of the 3D object profile depends on the correct and accurate position response of each detector as well as on the size of the PSD array. PMID:26633403

  3. Simulated and Real Sheet-of-Light 3D Object Scanning Using a-Si:H Thin Film PSD Arrays.

    PubMed

    Contreras, Javier; Tornero, Josep; Ferreira, Isabel; Martins, Rodrigo; Gomes, Luis; Fortunato, Elvira

    2015-01-01

    A MATLAB/SIMULINK software simulation model (structure and component blocks) has been constructed in order to view and analyze the potential of the PSD (Position Sensitive Detector) array concept technology before it is further expanded or developed. This simulation allows changing most of its parameters, such as the number of elements in the PSD array, the direction of vision, the viewing/scanning angle, the object rotation, translation, sample/scan/simulation time, etc. In addition, results show for the first time the possibility of scanning an object in 3D when using an a-Si:H thin film 128 PSD array sensor and hardware/software system. Moreover, this sensor technology is able to perform these scans and render 3D objects at high speeds and high resolutions when using a sheet-of-light laser within a triangulation platform. As shown by the simulation, a substantial enhancement in 3D object profile image quality and realism can be achieved by increasing the number of elements of the PSD array sensor as well as by achieving an optimal position response from the sensor since clearly the definition of the 3D object profile depends on the correct and accurate position response of each detector as well as on the size of the PSD array. PMID:26633403

  4. Transvaginal 3D Image-Guided High Intensity Focused Ultrasound Array

    NASA Astrophysics Data System (ADS)

    Held, Robert; Nguyen, Thuc Nghi; Vaezy, Shahram

    2005-03-01

    The goal of this project is to develop a transvaginal image-guided High Intensity Focused Ultrasound (HIFU) device using piezocomposite HIFU array technology, and commercially-available ultrasound imaging. Potential applications include treatment of uterine fibroids and abnormal uterine bleeding. The HIFU transducer was an annular phased array, with a focal length range of 30-60 mm, an elliptically-shaped aperture of 35×60 mm, and an operating frequency of 3 MHz. A pillow-shaped bag with water circulation will be used for coupling the HIFU energy into the tissue. An intra-cavity imaging probe (C9-5, Philips) was integrated with the HIFU array such that the focal axis of the HIFU transducer was within the image plane. The entire device will be covered by a gel-filled condom when inserted in the vaginal cavity. To control it, software packages were developed in the LabView programming environment. An imaging algorithm processed the ultrasound image to remove noise patterns due to the HIFU signal. The device will be equipped with a three-dimensional tracking system, using a six-degrees-of-freedom articulating arm. Necrotic lesions were produced in a tissue-mimicking phantom and a turkey breast sample for all focal lengths. Various HIFU doses allow various necrotic lesion shapes, including thin ellipsoidal, spherical, wide cylindrical, and teardrop-shaped. Software control of the device allows multiple foci to be activated sequentially for desired lesion patterns. Ultrasound imaging synchronization can be achieved using hardware signals obtained from the imaging system, or software signals determined empirically for various imaging probes. The image-guided HIFU device will provide a valuable tool in visualization of uterine fibroid tumors for the purposes of planning and subsequent HIFU treatment of the tumor, all in a 3D environment. The control system allows for various lesions of different shapes to be optimally positioned in the tumor to cover the entire tumor

  5. Enhancement of the excitation efficiency of a torsional wave PPM EMAT array for pipe inspection by optimizing the element number of the array based on 3-D FEM.

    PubMed

    Wang, Yugang; Wu, Xinjun; Sun, Pengfei; Li, Jian

    2015-01-01

    Electromagnetic acoustic transducers (EMATs) can generate non-dispersive T(0,1) mode guided waves in a metallic pipe for nondestructive testing (NDT) by using a periodic permanent magnet (PPM) EMAT circular array. In order to enhance the excitation efficiency of the sensor, the effects of varying the number of elements of the array on the excitation efficiency is studied in this paper. The transduction process of the PPM EMAT array is studied based on 3-D finite element method (FEM). The passing signal amplitude of the torsional wave is obtained to represent the excitation efficiency of the sensor. Models with different numbers of elements are established and the results are compared to obtain an optimal element number. The simulation result is verified by experiments. It is shown that after optimization, the amplitudes of both the passing signal and defect signal with the optimal element number are increased by 29%, which verifies the feasibility of this optimal method. The essence of the optimization is to find the best match between the static magnetic field and the eddy current field in a limited circumferential space to obtain the maximum circumferential Lorentz force. PMID:25654722

  6. Enhancement of the Excitation Efficiency of a Torsional Wave PPM EMAT Array for Pipe Inspection by Optimizing the Element Number of the Array Based on 3-D FEM

    PubMed Central

    Wang, Yugang; Wu, Xinjun; Sun, Pengfei; Li, Jian

    2015-01-01

    Electromagnetic acoustic transducers (EMATs) can generate non-dispersive T(0,1) mode guided waves in a metallic pipe for nondestructive testing (NDT) by using a periodic permanent magnet (PPM) EMAT circular array. In order to enhance the excitation efficiency of the sensor, the effects of varying the number of elements of the array on the excitation efficiency is studied in this paper. The transduction process of the PPM EMAT array is studied based on 3-D finite element method (FEM). The passing signal amplitude of the torsional wave is obtained to represent the excitation efficiency of the sensor. Models with different numbers of elements are established and the results are compared to obtain an optimal element number. The simulation result is verified by experiments. It is shown that after optimization, the amplitudes of both the passing signal and defect signal with the optimal element number are increased by 29%, which verifies the feasibility of this optimal method. The essence of the optimization is to find the best match between the static magnetic field and the eddy current field in a limited circumferential space to obtain the maximum circumferential Lorentz force. PMID:25654722

  7. 3D parameter to quantify the anisotropy measurement of periodic structures on rough surfaces.

    PubMed

    Guillemot, G; Bigerelle, M; Khawaja, Z

    2014-01-01

    In this paper, a new 3D roughness parameter, Sreg, is proposed to quantify the regularity of a surface, independent of the amplitude and the scanning length units of the surface. The efficiency of this parameter is tested on noisy periodical surfaces with degrees of anisotropy. This parameter lies between zero (perfect noise) and 100% (a perfect periodic surface). This parameter enables the identification of the anisotropy directions of regularity for a given surface. For a periodical surface, the greater the noise, the lower the anisotropy. A direction function is proposed to analyse the direction of regularity of a rough surface, which then permits characterization of the directional regularity of the topography. The regularity parameter can be used for several purposes: to identify the direction of periodical structures formed by laser-pulsed radiations on the surface of solid workpieces; to examine the reproducibility of surface machining methods such as finishing process; and to identify the surface regularity produced by abrasive machining, such as precision surface grain, abrasive slotting, and lapping. PMID:23824916

  8. Switchable 3D liquid crystal grating generated by periodic photo-alignment on both substrates.

    PubMed

    Nys, I; Beeckman, J; Neyts, K

    2015-10-21

    A planar liquid crystal (LC) cell is developed in which two photo-alignment layers have been illuminated with respectively a horizontal and a vertical diffraction pattern of interfering left- and right-handed circularly polarized light. In the bulk of the cell, a complex LC configuration is obtained with periodicity in two dimensions. Remarkably, the period of the structure is larger than the period of the interference pattern, indicating that lowering of the symmetry allows a reduction in the elastic energy. The liquid crystal configuration depends on the periodicity of the alignment but also on the thickness of the cell. By applying a voltage over the electrodes, the power going into the different diffracted orders can be tuned. Finite element (FE) simulations based on Q-tensor theory are used to find the 3D equilibrium director distribution, which is used to simulate the near-field transmission profile based on the Jones calculus. A 2D Fourier transform is performed for both the x- and y-component of the transmitted wave to find the diffraction efficiency. PMID:26313442

  9. Theoretical and experimental study of DOA estimation using AML algorithm for an isotropic and non-isotropic 3D array

    NASA Astrophysics Data System (ADS)

    Asgari, Shadnaz; Ali, Andreas M.; Collier, Travis C.; Yao, Yuan; Hudson, Ralph E.; Yao, Kung; Taylor, Charles E.

    2007-09-01

    The focus of most direction-of-arrival (DOA) estimation problems has been based mainly on a two-dimensional (2D) scenario where we only need to estimate the azimuth angle. But in various practical situations we have to deal with a three-dimensional scenario. The importance of being able to estimate both azimuth and elevation angles with high accuracy and low complexity is of interest. We present the theoretical and the practical issues of DOA estimation using the Approximate-Maximum-Likelihood (AML) algorithm in a 3D scenario. We show that the performance of the proposed 3D AML algorithm converges to the Cramer-Rao Bound. We use the concept of an isotropic array to reduce the complexity of the proposed algorithm by advocating a decoupled 3D version. We also explore a modified version of the decoupled 3D AML algorithm which can be used for DOA estimation with non-isotropic arrays. Various numerical results are presented. We use two acoustic arrays each consisting of 8 microphones to do some field measurements. The processing of the measured data from the acoustic arrays for different azimuth and elevation angles confirms the effectiveness of the proposed methods.

  10. 3D ELM fluctuation measurements with the new dual array ECE-Imaging diagnostic on ASDEX Upgrade

    NASA Astrophysics Data System (ADS)

    Classen, Ivo; Vanovac, Branka; Domier, Calvin; Luhmann, Neville; Bogomolov, Anton; Suttrop, Wolfgang; Tobias, Benjamin; ASDEX Upgrade Team

    2015-11-01

    In a major upgrade, the (2D) electron cyclotron emission imaging diagnostic (ECE-Imaging) at ASDEX Upgrade (AUG) has been equipped with a second detector array, and has been successfully commissioned. The two detector arrays observe the plasma through the same vacuum window, both under a slight toroidal angle, to enable quasi-3D measurements of the electron temperature. The system measures a total of 288 channels, in two toroidally separated 2D arrays of approximately 50 cm vertically by 10 cm radially. The toroidal separation between the two poloidal observation planes is about 40 cm, such that the majority of the field lines is observed by both arrays simultaneously, thereby enabling a direct measurement of the 3D properties of plasma instabilities like ELM filaments. The toroidal separation of 40 cm is sufficient for the accurate measurement of both phase differences and transit times of (rotating) plasma structures, enabling a distinction between time varying 2D structures and true 3D structures (not possible with 2D diagnostics). The research will mainly focus on the investigation of the 3D structure of the temperature fluctuations related to edge localized modes (ELMs), in particular precursors and filaments. The first results on ELMs will be reported.

  11. Fast 3D dark-field reflection-mode photoacoustic microscopy in vivo with a 30-MHz ultrasound linear array

    PubMed Central

    Song, Liang; Maslov, Konstantin; Bitton, Rachel; Shung, K. Kirk; Wang, Lihong V.

    2009-01-01

    We present an in vivo dark-field reflection-mode photoacoustic microscopy system that performs cross-sectional (B-scan) imaging at 50 Hz with realtime beamforming and 3D imaging consisting of 166 B-scan frames at 1 Hz with post-beamforming. To our knowledge, this speed is currently the fastest in photoacoustic imaging. A custom-designed light delivery system is integrated with a 30-MHz ultrasound linear array to realize dark-field reflection-mode imaging. Linear mechanical scanning of the array produces 3D images. The system has axial, lateral, and elevational resolutions of 25, 70, and 200 μm, respectively, and can image 3 mm deep in scattering biological tissues. Volumetric images of subcutaneous vasculature in rats are demonstrated in vivo. Fast 3D photoacoustic microscopy is anticipated to facilitate applications of photoacoustic imaging in biomedical studies that involve dynamics and clinical procedures that demand immediate diagnosis. PMID:19021408

  12. New fabrication techniques for ring-array transducers for real-time 3D intravascular ultrasound.

    PubMed

    Light, Edward D; Lieu, Victor; Smith, Stephen W

    2009-10-01

    We have previously described miniature 2D array transducers integrated into a Cook Medical, Inc. vena cava filter deployment device. While functional, the fabrication technique was very labor intensive and did not lend itself well to efficient fabrication of large numbers of devices. We developed two new fabrication methods that we believe can be used to efficiently manufacture these types of devices in greater than prototype numbers. One transducer consisted of 55 elements operating near 5 MHz. The interelement spacing is 0.20 mm. It was constructed on a flat piece of copper-clad polyimide and then wrapped around an 11 French catheter of a Cook Medical, Inc. inferior vena cava (IVC) filter deployment device. We used a braided wiring technology from Tyco Electronics Corp. to connect the elements to our real-time 3D ultrasound scanner. Typical measured transducer element bandwidth was 20% centered at 4.7 MHz and the 50 Omega round trip insertion loss was --82 dB. The mean of the nearest neighbor cross talk was -37.0 dB. The second method consisted of a 46-cm long single layer flex circuit from MicroConnex that terminates in an interconnect that plugs directly into our system cable. This transducer had 70 elements at 0.157 mm interelement spacing operating at 4.8 MHz. Typical measured transducer element bandwidth was 29% and the 50 Omega round trip insertion loss was -83 dB. The mean of the nearest neighbor cross talk was -33.0 dB. PMID:20458877

  13. Combinatorial screening of osteoblast response to 3D calcium phosphate/poly(ε-caprolactone) scaffolds using gradients and arrays

    PubMed Central

    Chatterjee, Kaushik; Sun, Limin; Chow, Laurence C.; Young, Marian F.; Simon, Carl G.

    2012-01-01

    There is a need for combinatorial and high-throughput methods for screening cell–biomaterial interactions to maximize tissue generation in scaffolds. Current methods employ a flat two-dimensional (2D) format even though three-dimensional (3D) scaffolds are more representative of the tissue environment in vivo and cells are responsive to topographical differences of 2D substrates and 3D scaffolds. Thus, combinatorial libraries of 3D porous scaffolds were developed and used to screen the effect of nano-amorphous calcium phosphate (nACP) particles on osteoblast response. Increasing nACP content in poly (ε-caprolactone) (PCL) scaffolds promoted osteoblast adhesion and proliferation. The nACP-containing scaffolds released calcium and phosphate ions which are known to activate osteoblast function. Scaffold libraries were fabricated in two formats, gradients and arrays, and the magnitude of the effect of nACP on osteoblast proliferation was greater for arrays than gradients. The enhanced response in arrays can be explained by differences in cell culture designs, diffusional effects and differences in the ratio of “scaffold mass to culture medium”. These results introduce a gradient library approach for screening large pore 3D scaffolds and demonstrate that inclusion of the nACP particles enhances osteoblast proliferation in 3D scaffolds. Further, comparison of gradients and arrays suggests that gradients were more sensitive for detecting effects of scaffold composition on cell adhesion (short time points, 1 day) whereas arrays were more sensitive at detecting effects on cell proliferation (longer time points, 14 day). PMID:21074846

  14. Experimental results for a prototype 3-D acoustic imaging system using an ultra-sparse planar array

    NASA Astrophysics Data System (ADS)

    Impagliazzo, John M.; Chiang, Alice M.; Broadstone, Steven R.

    2002-11-01

    A handheld high resolution sonar has been under development to provide Navy Divers with a 3-D acoustic imaging system for mine reconnaissance. An ultra-sparse planar array, consisting of 121 1 mm x1 mm, 2 MHz elements, was fabricated to provide 3-D acoustic images. The array was 10 cm x10 cm. A full array at this frequency with elements at half-wavelength spacing would consist of 16384 elements. The first phase of testing of the planar array was completed in September 2001 with the characterization of the array in the NUWC Acoustic Test Facility (ATF). The center frequency was 2 MHz with a 667 kHz bandwidth. A system-level technology demonstration will be conducted in July 2002 with a real-time beamformer and near real-time 3-D imaging software. The demonstration phase consists of imaging simple targets at a range of 3 m in the ATF. Experimental results obtained will be reported on. [Work supported by the Defense Applied Research Project Agency, Advance Technology Office, Dr. Theo Kooij, Program Manager.

  15. 3D Bioprinting of Carboxymethylated-Periodate Oxidized Nanocellulose Constructs for Wound Dressing Applications

    PubMed Central

    Gethin, David T.; Syverud, Kristin; Hill, Katja E.; Thomas, David W.

    2015-01-01

    Nanocellulose has a variety of advantages, which make the material most suitable for use in biomedical devices such as wound dressings. The material is strong, allows for production of transparent films, provides a moist wound healing environment, and can form elastic gels with bioresponsive characteristics. In this study, we explore the application of nanocellulose as a bioink for modifying film surfaces by a bioprinting process. Two different nanocelluloses were used, prepared with TEMPO mediated oxidation and a combination of carboxymethylation and periodate oxidation. The combination of carboxymethylation and periodate oxidation produced a homogeneous material with short nanofibrils, having widths <20 nm and lengths <200 nm. The small dimensions of the nanofibrils reduced the viscosity of the nanocellulose, thus yielding a material with good rheological properties for use as a bioink. The nanocellulose bioink was thus used for printing 3D porous structures, which is exemplified in this study. We also demonstrated that both nanocelluloses did not support bacterial growth, which is an interesting property of these novel materials. PMID:26090461

  16. 3D Bioprinting of Carboxymethylated-Periodate Oxidized Nanocellulose Constructs for Wound Dressing Applications.

    PubMed

    Rees, Adam; Powell, Lydia C; Chinga-Carrasco, Gary; Gethin, David T; Syverud, Kristin; Hill, Katja E; Thomas, David W

    2015-01-01

    Nanocellulose has a variety of advantages, which make the material most suitable for use in biomedical devices such as wound dressings. The material is strong, allows for production of transparent films, provides a moist wound healing environment, and can form elastic gels with bioresponsive characteristics. In this study, we explore the application of nanocellulose as a bioink for modifying film surfaces by a bioprinting process. Two different nanocelluloses were used, prepared with TEMPO mediated oxidation and a combination of carboxymethylation and periodate oxidation. The combination of carboxymethylation and periodate oxidation produced a homogeneous material with short nanofibrils, having widths <20 nm and lengths <200 nm. The small dimensions of the nanofibrils reduced the viscosity of the nanocellulose, thus yielding a material with good rheological properties for use as a bioink. The nanocellulose bioink was thus used for printing 3D porous structures, which is exemplified in this study. We also demonstrated that both nanocelluloses did not support bacterial growth, which is an interesting property of these novel materials. PMID:26090461

  17. Highly uniform residual layers for arrays of 3D nanoimprinted cavities in Fabry-Pérot-filter-array-based nanospectrometers

    NASA Astrophysics Data System (ADS)

    Memon, Imran; Shen, Yannan; Khan, Abdullah; Woidt, Carsten; Hillmer, Hartmut

    2016-04-01

    Miniaturized optical spectrometers can be implemented by an array of Fabry-Pérot (FP) filters. FP filters are composed of two highly reflecting parallel mirrors and a resonance cavity. Each filter transmits a small spectral band (filter line) depending on its individual cavity height. The optical nanospectrometer, a miniaturized FP-based spectrometer, implements 3D NanoImprint technology for the fabrication of multiple FP filter cavities in a single process step. However, it is challenging to avoid the dependency of residual layer (RL) thickness on the shape of the printed patterns in NanoImprint. Since in a nanospectrometer the filter cavities vary in height between neighboring FP filters and, thus, the volume of each cavity varies causing that the RL varies slightly or noticeably between different filters. This is one of the few disadvantages of NanoImprint using soft templates such as substrate conformal imprint lithography which is used in this paper. The advantages of large area soft templates can be revealed substantially if the problem of laterally inhomogeneous RLs can be avoided or reduced considerably. In the case of the nanospectrometer, non-uniform RLs lead to random variations in the designed cavity heights resulting in the shift of desired filter lines. To achieve highly uniform RLs, we report a volume-equalized template design with the lateral distribution of 64 different cavity heights into several units with each unit comprising four cavity heights. The average volume of each unit is kept constant to obtain uniform filling of imprint material per unit area. The imprint results, based on the volume-equalized template, demonstrate highly uniform RLs of 110 nm thickness.

  18. Micro-lens array based 3-D color image encryption using the combination of gravity model and Arnold transform

    NASA Astrophysics Data System (ADS)

    You, Suping; Lu, Yucheng; Zhang, Wei; Yang, Bo; Peng, Runling; Zhuang, Songlin

    2015-11-01

    This paper proposes a 3-D image encryption scheme based on micro-lens array. The 3-D image can be reconstructed by applying the digital refocusing algorithm to the picked-up light field. To improve the security of the cryptosystem, the Arnold transform and the Gravity Model based image encryption method are employed. Experiment results demonstrate the high security in key space of the proposed encryption scheme. The results also indicate that the employment of light field imaging significant strengthens the robustness of the cipher image against some conventional image processing attacks.

  19. Dimensional phase transition from an array of 1D Luttinger liquids to a 3D Bose-Einstein condensate.

    PubMed

    Vogler, Andreas; Labouvie, Ralf; Barontini, Giovanni; Eggert, Sebastian; Guarrera, Vera; Ott, Herwig

    2014-11-21

    We study the thermodynamic properties of a 2D array of coupled one-dimensional Bose gases. The system is realized with ultracold bosonic atoms loaded in the potential tubes of a two-dimensional optical lattice. For negligible coupling strength, each tube is an independent weakly interacting 1D Bose gas featuring Tomonaga Luttinger liquid behavior. By decreasing the lattice depth, we increase the coupling strength between the 1D gases and allow for the phase transition into a 3D condensate. We extract the phase diagram for such a system and compare our results with theoretical predictions. Because of the high effective mass across the periodic potential and the increased 1D interaction strength, the phase transition is shifted to large positive values of the chemical potential. Our results are prototypical to a variety of low-dimensional systems, where the coupling between the subsystems is realized in a higher spatial dimension such as coupled spin chains in magnetic insulators. PMID:25479499

  20. Increase in the energy density of the pinch plasma in 3D implosion of quasi-spherical wire arrays

    SciTech Connect

    Aleksandrov, V. V.; Gasilov, V. A.; Grabovski, E. V.; Gritsuk, A. N. Laukhin, Ya. N.; Mitrofanov, K. N.; Oleinik, G. M.; Ol’khovskaya, O. G.; Sasorov, P. V.; Smirnov, V. P.; Frolov, I. N.; Shevel’ko, A. P.

    2014-12-15

    Results are presented from experimental studies of the characteristics of the soft X-ray (SXR) source formed in the implosion of quasi-spherical arrays made of tungsten wires and metalized kapron fibers. The experiments were carried out at the Angara-5-1 facility at currents of up to 3 MA. Analysis of the spatial distribution of hard X-ray emission with photon energies above 20 keV in the pinch images taken during the implosion of quasi-spherical tungsten wire arrays (QTWAs) showed that a compact quasi-spherical plasma object symmetric with respect to the array axis formed in the central region of the array. Using a diffraction grazing incidence spectrograph, spectra of SXR emission with wavelengths of 20–400 Å from the central, axial, and peripheral regions of the emission source were measured with spatial resolutions along the array radius and height in the implosion of QTWAs. It is shown that the emission spectra of the SXR sources formed under the implosion of quasi-spherical and cylindrical tungsten wire arrays at currents of up to 3 MA have a maximum in the wavelength range of 50–150 Å. It is found that, during the implosion of a QTWA with a profiled linear mass, a redistribution of energy in the emission spectrum takes place, which indicates that, during 3D implosion, the energy of longitudinal motion of the array material additionally contributes to the radiation energy. It is also found that, at close masses of the arrays and close values of the current in the range of 2.4{sup −3} MA, the average energy density in the emission source formed during the implosion of a quasi-spherical wire array is larger by a factor of 7 than in the source formed during the implosion of a cylindrical wire array. The experimental data were compared with results of 3D simulations of plasma dynamics and radiation generation during the implosion of quasi-spherical wire arrays with a profiled mass by using the MARPLE-3D radiative magnetohydrodynamic code, developed at the

  1. Affective SSVEP BCI to effectively control 3D objects by using a prism array-based display

    NASA Astrophysics Data System (ADS)

    Mun, Sungchul; Park, Min-Chul

    2014-06-01

    3D objects with depth information can provide many benefits to users in education, surgery, and interactions. In particular, many studies have been done to enhance sense of reality in 3D interaction. Viewing and controlling stereoscopic 3D objects with crossed or uncrossed disparities, however, can cause visual fatigue due to the vergenceaccommodation conflict generally accepted in 3D research fields. In order to avoid the vergence-accommodation mismatch and provide a strong sense of presence to users, we apply a prism array-based display to presenting 3D objects. Emotional pictures were used as visual stimuli in control panels to increase information transfer rate and reduce false positives in controlling 3D objects. Involuntarily motivated selective attention by affective mechanism can enhance steady-state visually evoked potential (SSVEP) amplitude and lead to increased interaction efficiency. More attentional resources are allocated to affective pictures with high valence and arousal levels than to normal visual stimuli such as white-and-black oscillating squares and checkerboards. Among representative BCI control components (i.e., eventrelated potentials (ERP), event-related (de)synchronization (ERD/ERS), and SSVEP), SSVEP-based BCI was chosen in the following reasons. It shows high information transfer rates and takes a few minutes for users to control BCI system while few electrodes are required for obtaining reliable brainwave signals enough to capture users' intention. The proposed BCI methods are expected to enhance sense of reality in 3D space without causing critical visual fatigue to occur. In addition, people who are very susceptible to (auto) stereoscopic 3D may be able to use the affective BCI.

  2. An ultra-high element density pMUT array with low crosstalk for 3-D medical imaging.

    PubMed

    Yang, Yi; Tian, He; Wang, Yu-Feng; Shu, Yi; Zhou, Chang-Jian; Sun, Hui; Zhang, Cang-Hai; Chen, Hao; Ren, Tian-Ling

    2013-01-01

    A ~1 MHz piezoelectric micromachined ultrasonic transducer (pMUT) array with ultra-high element density and low crosstalk is proposed for the first time. This novel pMUT array is based on a nano-layer spin-coating lead zirconium titanium film technique and can be fabricated with high element density using a relatively simple process. Accordingly, key fabrication processes such as thick piezoelectric film deposition, low-stress Si-SOI bonding and bulk silicon removal have been successfully developed. The novel fine-pitch 6 × 6 pMUT arrays can all work at the desired frequency (~1 MHz) with good uniformity, high performance and potential IC integration compatibility. The minimum interspace is ~20 μm, the smallest that has ever been achieved to the best of our knowledge. These arrays can be potentially used to steer ultrasound beams and implement high quality 3-D medical imaging applications. PMID:23896705

  3. From micro-scale 3D simulations to macro-scale model of periodic porous media

    NASA Astrophysics Data System (ADS)

    Crevacore, Eleonora; Tosco, Tiziana; Marchisio, Daniele; Sethi, Rajandrea; Messina, Francesca

    2015-04-01

    In environmental engineering, the transport of colloidal suspensions in porous media is studied to understand the fate of potentially harmful nano-particles and to design new remediation technologies. In this perspective, averaging techniques applied to micro-scale numerical simulations are a powerful tool to extrapolate accurate macro-scale models. Choosing two simplified packing configurations of soil grains and starting from a single elementary cell (module), it is possible to take advantage of the periodicity of the structures to reduce the computation costs of full 3D simulations. Steady-state flow simulations for incompressible fluid in laminar regime are implemented. Transport simulations are based on the pore-scale advection-diffusion equation, that can be enriched introducing also the Stokes velocity (to consider the gravity effect) and the interception mechanism. Simulations are carried on a domain composed of several elementary modules, that serve as control volumes in a finite volume method for the macro-scale method. The periodicity of the medium involves the periodicity of the flow field and this will be of great importance during the up-scaling procedure, allowing relevant simplifications. Micro-scale numerical data are treated in order to compute the mean concentration (volume and area averages) and fluxes on each module. The simulation results are used to compare the micro-scale averaged equation to the integral form of the macroscopic one, making a distinction between those terms that could be computed exactly and those for which a closure in needed. Of particular interest it is the investigation of the origin of macro-scale terms such as the dispersion and tortuosity, trying to describe them with micro-scale known quantities. Traditionally, to study the colloidal transport many simplifications are introduced, such those concerning ultra-simplified geometry that usually account for a single collector. Gradual removal of such hypothesis leads to a

  4. Design and performance of a fiber array coupled multi-channel photon counting, 3D imaging, airborne lidar system

    NASA Astrophysics Data System (ADS)

    Huang, Genghua; Shu, Rong; Hou, Libing; Li, Ming

    2014-06-01

    Photon counting lidar has an ultra-high sensitivity which can be hundreds even thousands of times higher than the linear detection lidar. It can significantly increase the system's capability of detection rang and imaging density, saving size and power consumings in airborne or space-borne applications. Based on Geiger-mode Si avalanche photodiodes (Si-APD), a prototype photon counting lidar which used 8 APDs coupled with a 1×8-pixel fiber array has been made in June, 2011. The experiments with static objects showed that the photon counting lidar could operate in strong solar background with 0.04 receiving photoelectrons on average. Limited by less counting times in moving platforms, the probability of detection and the 3D imaging density would be lower than that in static platforms. In this paper, a latest fiber array coupled multi-channel photon counting, 3D imaging, airborne lidar system is introduced. The correlation range receiver algorithm of photon counting 3D imaging is improved for airborne signal photon events extraction and noise filter. The 3D imaging experiments in the helicopter shows that the false alarm rate is less than 6×10-7, and the correct rate is better than 99.9% with 4 received photoelectrons and 0.7MHz system noise on average.

  5. A 3-D spectral-element and frequency-wave number hybrid method for high-resolution seismic array imaging

    NASA Astrophysics Data System (ADS)

    Tong, Ping; Komatitsch, Dimitri; Tseng, Tai-Lin; Hung, Shu-Huei; Chen, Chin-Wu; Basini, Piero; Liu, Qinya

    2014-10-01

    We present a three-dimensional (3-D) hybrid method that interfaces the spectral-element method (SEM) with the frequency-wave number (FK) technique to model the propagation of teleseismic plane waves beneath seismic arrays. The accuracy of the resulting 3-D SEM-FK hybrid method is benchmarked against semianalytical FK solutions for 1-D models. The accuracy of 2.5-D modeling based on 2-D SEM-FK hybrid method is also investigated through comparisons to this 3-D hybrid method. Synthetic examples for structural models of the Alaska subduction zone and the central Tibet crust show that this method is capable of accurately capturing interactions between incident plane waves and local heterogeneities. This hybrid method presents an essential tool for the receiver function and scattering imaging community to verify and further improve their techniques. These numerical examples also show the promising future of the 3-D SEM-FK hybrid method in high-resolution regional seismic imaging based on waveform inversions of converted/scattered waves recorded by seismic array.

  6. Production of Uniform 3D Microtumors in Hydrogel Microwell Arrays for Measurement of Viability, Morphology, and Signaling Pathway Activation.

    PubMed

    Singh, Manjulata; Close, David A; Mukundan, Shilpaa; Johnston, Paul A; Sant, Shilpa

    2015-11-01

    Despite significant investments in cancer research and drug discovery/development, the rate of new cancer drug approval is ≤5% and most cases of metastatic cancer remain incurable. Ninety-five percent of new cancer drugs fail in clinical development because of a lack of therapeutic efficacy and/or unacceptable toxicity. One of the major factors responsible for the low success rate of anticancer drug development is the failure of preclinical models to adequately recapitulate the complexity and heterogeneity of human cancer. For throughput and capacity reasons, high-throughput screening growth inhibition assays almost exclusively use two-dimensional (2D) monolayers of tumor cell lines cultured on tissue culture-treated plastic/glass surfaces in serum-containing medium. However, these 2D tumor cell line cultures fail to recapitulate the three-dimensional (3D) context of cells in solid tumors even though the tumor microenvironment has been shown to have a profound effect on anticancer drug responses. Tumor spheroids remain the best characterized and most widely used 3D models; however, spheroid sizes tend to be nonuniform, making them unsuitable for high-throughput drug testing. To circumvent this challenge, we have developed defined size microwell arrays using nonadhesive hydrogels that are applicable to a wide variety of cancer cell lines to fabricate size-controlled 3D microtumors. We demonstrate that the hydrogel microwell array platform can be applied successfully to generate hundreds of uniform microtumors within 3-6 days from many cervical and breast, as well as head and neck squamous cell carcinoma (HNSCC) cells. Moreover, controlling size of the microwells in the hydrogel array allows precise control over the size of the microtumors. Finally, we demonstrate the application of this platform technology to probe activation as well as inhibition of epidermal growth factor receptor (EGFR) signaling in 3D HNSCC microtumors in response to EGF and cetuximab

  7. 3D vector flow using a row-column addressed CMUT array

    NASA Astrophysics Data System (ADS)

    Holbek, Simon; Christiansen, Thomas Lehrmann; Engholm, Mathias; Lei, Anders; Stuart, Mathias Bo; Beers, Christopher; Moesner, Lars Nordahl; Bagge, Jan Peter; Thomsen, Erik Vilain; Jensen, Jørgen Arendt

    2016-04-01

    This paper presents an in-house developed 2-D capacitive micromachined ultrasonic transducer (CMUT) applied for 3-D blood flow estimation. The probe breaks with conventional transducers in two ways; first, the ultrasonic pressure field is generated from thousands of small vibrating micromachined cells, and second, elements are accessed by row and/or column indices. The 62+62 2-D row-column addressed prototype CMUT probe was used for vector flow estimation by transmitting focused ultrasound into a flow-rig with a fully developed parabolic flow. The beam-to-flow angle was 90°. The received data was beamformed and processed offline. A transverse oscillation (TO) velocity estimator was used to estimate the 3-D vector flow along a line originating from the center of the transducer. The estimated velocities in the lateral and axial direction were close to zero as expected. In the transverse direction a characteristic parabolic velocity profile was estimated with a peak velocity of 0.48 m/s +/- 0.02 m/s in reference to the expected 0.54 m/s. The results presented are the first 3-D vector flow estimates obtained with a row-column CMUT probe, which demonstrates that the CMUT technology is feasible for 3-D flow estimation.

  8. A floating 3D silicon microprobe array for neural drug delivery compatible with electrical recording

    NASA Astrophysics Data System (ADS)

    Spieth, S.; Brett, O.; Seidl, K.; Aarts, A. A. A.; Erismis, M. A.; Herwik, S.; Trenkle, F.; Tätzner, S.; Auber, J.; Daub, M.; Neves, H. P.; Puers, R.; Paul, O.; Ruther, P.; Zengerle, R.

    2011-12-01

    This paper reports on the design, fabrication, assembly and characterization of a three-dimensional silicon-based floating microprobe array for localized drug delivery to be applied in neuroscience research. The microprobe array is composed of a silicon platform into which up to four silicon probe combs with needle-like probe shafts can be inserted. Two dedicated positions in the array allow the integration of combs for drug delivery. The implemented comb variants feature 8 mm long probe shafts with two individually addressable microchannels incorporated in a single shaft or distributed to two shafts. Liquid supply to the array is realized by a highly flexible 250 µm thick multi-lumen microfluidic cable made from polydimethylsiloxane (PDMS). The specific design concept of the slim-base platform enables floating implantation of the array in the small space between brain and skull. In turn, the flexible cable mechanically decouples the array from any microfluidic interface rigidly fixed to the skull. After assembly of the array, full functionality is demonstrated and characterized at infusion rates from 1 to 5 µL min-1. Further, the effect of a parylene-C coating on the water vapour and osmotic liquid water transport through the PDMS cable walls is experimentally evaluated by determining the respective transmission rates including the water vapour permeability of the used PDMS type.

  9. All oxide semiconductor-based bidirectional vertical p-n-p selectors for 3D stackable crossbar-array electronics

    PubMed Central

    Bae, Yoon Cheol; Lee, Ah Rahm; Baek, Gwang Ho; Chung, Je Bock; Kim, Tae Yoon; Park, Jea Gun; Hong, Jin Pyo

    2015-01-01

    Three-dimensional (3D) stackable memory devices including nano-scaled crossbar array are central for the realization of high-density non-volatile memory electronics. However, an essential sneak path issue affecting device performance in crossbar array remains a bottleneck and a grand challenge. Therefore, a suitable bidirectional selector as a two-way switch is required to facilitate a major breakthrough in the 3D crossbar array memory devices. Here, we show the excellent selectivity of all oxide p-/n-type semiconductor-based p-n-p open-based bipolar junction transistors as selectors in crossbar memory array. We report that bidirectional nonlinear characteristics of oxide p-n-p junctions can be highly enhanced by manipulating p-/n-type oxide semiconductor characteristics. We also propose an associated Zener tunneling mechanism that explains the unique features of our p-n-p selector. Our experimental findings are further extended to confirm the profound functionality of oxide p-n-p selectors integrated with several bipolar resistive switching memory elements working as storage nodes. PMID:26289565

  10. Experimental comparison of laser speckle projection and array projection for high-speed 3D measurements

    NASA Astrophysics Data System (ADS)

    Heist, Stefan; Lutzke, Peter; Dietrich, Patrick; Kühmstedt, Peter; Notni, Gunther

    2015-05-01

    In many application areas, stereo vision-based active triangulation systems are used to reconstruct the three-dimensional (3-D) surface shape of measurement objects. Typically, in order to solve the correspondence problem and increase the accuracy of the pixel assignment, a sequence of patterns is projected onto the object's surface and simultaneously recorded by two cameras. Most 3-D measurement systems are limited to static objects. In order to enhance their speed, it is necessary to use fast cameras as well as fast projection systems. Although high-speed camera systems are available, pattern projection at high frame rates is a difficult task and only a few techniques exist at the moment. In this contribution, we compare two different projection approaches, a laser-based speckle projection unit and an LED-based multi-aperture projection system, with regard to the achievable point cloud completeness and accuracy.

  11. A 3D Seismic Velocity Model Offshore Southern California from Ambient Noise Tomography of the ALBACORE OBS Array

    NASA Astrophysics Data System (ADS)

    Kohler, M. D.; Bowden, D. C.; Tsai, V. C.; Weeraratne, D. S.

    2015-12-01

    The Pacific-North America plate boundary in Southern California extends far west of the coastline, and a 12-month ocean bottom seismometer (OBS) array spanned the western side of the plate boundary to image lithospheric seismic velocities. Velocities are modeled through stacked cross correlations of ambient noise data. Twelve months of continuous data were used from 22 OBS stations and ~30 coastal and island Southern California Seismic Network stations. Particular attention has been paid to improving signal-to-noise ratios in the noise correlations with OBS stations by removing the effects of instrument tilt and infragravity waves. Different applications of preprocessing techniques allow us to distinguish the fundamental and first higher order Rayleigh modes, especially in deep water OBS pairs where the water layer dominates crustal sensitivity of the fundamental mode. Standard time domain and frequency domain methods are used to examine surface wave dispersion curves for group and phase velocities between 5 and 50 second periods, and these are inverted for 3D velocity structure. The results define the transition in three dimensions from continental lithospheric structure in the near-shore region to oceanic structure west of the continental borderland. While the most prominent features of the model relate to thinning of the crust west of the Patton Escarpment, other notable anomalies are present north-to-south throughout the continental borderland and along the coast from the Los Angeles Basin to the Peninsular Ranges. The velocity model will help describe the region's tectonic history, as well as provide new constraints for determination of earthquake relocations and rupture styles.

  12. An orientation measurement method based on Hall-effect sensors for permanent magnet spherical actuators with 3D magnet array.

    PubMed

    Yan, Liang; Zhu, Bo; Jiao, Zongxia; Chen, Chin-Yin; Chen, I-Ming

    2014-01-01

    An orientation measurement method based on Hall-effect sensors is proposed for permanent magnet (PM) spherical actuators with three-dimensional (3D) magnet array. As there is no contact between the measurement system and the rotor, this method could effectively avoid friction torque and additional inertial moment existing in conventional approaches. Curved surface fitting method based on exponential approximation is proposed to formulate the magnetic field distribution in 3D space. The comparison with conventional modeling method shows that it helps to improve the model accuracy. The Hall-effect sensors are distributed around the rotor with PM poles to detect the flux density at different points, and thus the rotor orientation can be computed from the measured results and analytical models. Experiments have been conducted on the developed research prototype of the spherical actuator to validate the accuracy of the analytical equations relating the rotor orientation and the value of magnetic flux density. The experimental results show that the proposed method can measure the rotor orientation precisely, and the measurement accuracy could be improved by the novel 3D magnet array. The study result could be used for real-time motion control of PM spherical actuators. PMID:25342000

  13. An Orientation Measurement Method Based on Hall-effect Sensors for Permanent Magnet Spherical Actuators with 3D Magnet Array

    NASA Astrophysics Data System (ADS)

    Yan, Liang; Zhu, Bo; Jiao, Zongxia; Chen, Chin-Yin; Chen, I.-Ming

    2014-10-01

    An orientation measurement method based on Hall-effect sensors is proposed for permanent magnet (PM) spherical actuators with three-dimensional (3D) magnet array. As there is no contact between the measurement system and the rotor, this method could effectively avoid friction torque and additional inertial moment existing in conventional approaches. Curved surface fitting method based on exponential approximation is proposed to formulate the magnetic field distribution in 3D space. The comparison with conventional modeling method shows that it helps to improve the model accuracy. The Hall-effect sensors are distributed around the rotor with PM poles to detect the flux density at different points, and thus the rotor orientation can be computed from the measured results and analytical models. Experiments have been conducted on the developed research prototype of the spherical actuator to validate the accuracy of the analytical equations relating the rotor orientation and the value of magnetic flux density. The experimental results show that the proposed method can measure the rotor orientation precisely, and the measurement accuracy could be improved by the novel 3D magnet array. The study result could be used for real-time motion control of PM spherical actuators.

  14. The 3D split-ring cavity lattice: a new metastructure for engineering arrays of coupled microwave harmonic oscillators

    NASA Astrophysics Data System (ADS)

    Goryachev, Maxim; Tobar, Michael E.

    2015-02-01

    A new electromagnetic cavity structure, a lattice of 3D cavities consisting of an array of posts and gaps is presented. The individual cavity elements are based on the cylindrical re-entrant (or Klystron) cavity. We show that these cavities can also be thought of as 3D split-ring resonators, which is confirmed by applying symmetry transformations, each of which is an electromagnetic resonator with spatially separated magnetic and electric field. The characteristics of the cavity is used to mimic phonon behaviour of a one-dimensional (1D) chain of atoms. It is demonstrated how magnetic field coupling can lead to phonon-like dispersion curves with acoustical and optical branches. The system is able to reproduce a number of effects typical to 1D lattices exhibiting acoustic vibration, such as band gaps, phonon trapping, and effects of impurities. In addition, quasicrystal emulations predict the results expected from this class of ordered structures. The system is easily scalable to simulate two-dimensional and 3D lattices and shows a new way to engineer arrays of coupled microwave resonators with a variety of possible applications to hybrid quantum systems proposed.

  15. 3D branched ZnO nanowire arrays decorated with plasmonic au nanoparticles for high-performance photoelectrochemical water splitting.

    PubMed

    Zhang, Xing; Liu, Yang; Kang, Zhenhui

    2014-03-26

    Plasmonic photoelectrochemical (PEC) water splitting is very promising in the conversion of abundant solar energy into chemical energy. However, the solar-to-hydrogen efficiencies reported so far are still too low for practical use, which can be improved by optimizing the design and synthesis of individual blocks (i. e., the compositions, sizes, shapes of the metal and the coupling semiconductors) and the assembly of these blocks into targeted three-dimensional (3D) structures. Here, we constructed a composite plasmonic metal/semiconductor photoanode by decorating gold nanoparticles (Au NPs) on 3D branched ZnO nanowire arrays (B-ZnO NWs) through a series of simple solution chemical routes. The 3D ordered Au/B-ZnO NWs photoanodes exhibited excellent PEC activities in both ultraviolet and visible region. The improved photoactivities in visible region were demonstrated to be caused by the surface-plasmon-resonance effect of Au NPs. The photoconversion efficiency of Au/B-ZnO NWs photoanode reached 0.52% under simulated sunlight illumination. This is a high value of solar-to-hydrogen efficiencies reported till nowadays for plasmonic PEC water splitting, which was mainly benefit from the extensive metal/semiconductor interfaces for efficient extraction of hot electron from Au NPs and excellent charge-carries collection efficiency of the 3D ordered Au/B-ZnO NWs photoelectrode. PMID:24598779

  16. 3D periodic multiscale TiO2 architecture: a platform decorated with graphene quantum dots for enhanced photoelectrochemical water splitting

    NASA Astrophysics Data System (ADS)

    Xu, Zhen; Yin, Min; Sun, Jing; Ding, Guqiao; Lu, Linfeng; Chang, Paichun; Chen, Xiaoyuan; Li, Dongdong

    2016-03-01

    Micropatterned TiO2 nanorods (TiO2NRs) via three-dimensional (3D) geometry engineering in both microscale and nanoscale decorated with graphene quantum dots (GQDs) have been demonstrated successfully. First, micropillar (MP) and microcave (MC) arrays of anatase TiO2 films are obtained through the sol-gel based thermal nanoimprinting method. Then they are employed as seed layers in hydrothermal growth to fabricate the 3D micropillar/microcave arrays of rutile TiO2NRs (NR), which show much-improved photoelectrochemical water-splitting performance than the TiO2NRs grown on flat seed layer. The zero-dimensional GQDs are sequentially deposited onto the surfaces of the microscale patterned nanorods. Owing to the fast charge separation that resulted from the favorable band alignment of the GQDs and rutile TiO2, the MP-NR-GQDs electrode achieves a photocurrent density up to 2.92 mA cm-2 under simulated one-sun illumination. The incident-photon-to-current-conversion efficiency (IPCE) value up to 72% at 370 nm was achieved on the MP-NR-GQDs electrode, which outperforms the flat-NR counterpart by 69%. The IPCE results also imply that the improved photocurrent mainly benefits from the distinctly enhanced ultraviolet response. The work provides a cost-effective and flexible pathway to develop periodic 3D micropatterned photoelectrodes and is promising for the future deployment of high performance optoelectronic devices.

  17. Verification of Long Period Surface Waves from Ambient Noise and Its Application in Constructing 3D Shear Wave Structure of Lithosphere in United States

    NASA Astrophysics Data System (ADS)

    Xie, J.; Yang, Y.; Ni, S.; Zhao, K.

    2015-12-01

    In the past decade, ambient noise tomography (ANT) has become an estimated method to construct the earth's interior structures thanks to its advantage in extracting surface waves from cross-correlations of ambient noise without using earthquake data. However, most of previous ambient noise tomography studies concentrate on short and intermediate periods (<50sec) due to the dominant energy of the microseism at these periods. Studies of long period surface waves from cross-correlation of ambient noise are limited. In this study, we verify the accuracy of the long period (50-250sec) surface wave (Rayleigh wave) from ambient noise by comparing both dispersion curves and seismic waveforms from ambient noise with those from earthquake records quantitatively. After that, we calculate vertical-vertical cross-correlation functions among more than1800 USArray Transportable Array stations and extract high quality interstation phase velocity dispersion curves from them at 10-200 sec periods. Then, we adopt a finite frequency ambient noise tomography method based on Born approximation to obtain high resolution phase velocity maps using the obtained dispersion measurements at 10-150 sec periods. Afterward, we extract local dispersion curves from these dispersion maps and invert them for 1D shear wave velocity profiles at individual grids using a Bayesian Monte Carlo method. Finally, a 3D shear velocity model is constructed by assembling all the 1D Vs profiles. Our 3D model is overall similar to other models constructed using earthquake surface waves and body waves. In summary, we demonstrate that the long period surface waves can be extracted from ambient noise, and the long period dispersion measurements from ambient noise are as accurate as those from earthquake data and can be used to construct 3D lithospheric structure from surface down to lithosphere/asthenosphere depths.

  18. Super non-linear RRAM with ultra-low power for 3D vertical nano-crossbar arrays.

    PubMed

    Luo, Qing; Xu, Xiaoxin; Liu, Hongtao; Lv, Hangbing; Gong, Tiancheng; Long, Shibing; Liu, Qi; Sun, Haitao; Banerjee, Writam; Li, Ling; Gao, Jianfeng; Lu, Nianduan; Liu, Ming

    2016-08-25

    Vertical crossbar arrays provide a cost-effective approach for high density three-dimensional (3D) integration of resistive random access memory. However, an individual selector device is not allowed to be integrated with the memory cell separately. The development of V-RRAM has impeded the lack of satisfactory self-selective cells. In this study, we have developed a high performance bilayer self-selective device using HfO2 as the memory switching layer and a mixed ionic and electron conductor as the selective layer. The device exhibits high non-linearity (>10(3)) and ultra-low half-select leakage (<0.1 pA). A four layer vertical crossbar array was successfully demonstrated based on the developed self-selective device. High uniformity, ultra-low leakage, sub-nA operation, self-compliance, and excellent read/write disturbance immunity were achieved. The robust array level performance shows attractive potential for low power and high density 3D data storage applications. PMID:27510434

  19. Measurements of stress fields near a grain boundary: Exploring blocked arrays of dislocations in 3D

    DOE PAGESBeta

    Guo, Y.; Collins, D. M.; Tarleton, E.; Hofmann, F.; Tischler, J.; Liu, W.; Xu, R.; Wilkinson, A. J.; Britton, T. B.

    2015-06-24

    The interaction between dislocation pile-ups and grain boundaries gives rise to heterogeneous stress distributions when a structural metal is subjected to mechanical loading. Such stress heterogeneity leads to preferential sites for damage nucleation and therefore is intrinsically linked to the strength and ductility of polycrystalline metals. To date the majority of conclusions have been drawn from 2D experimental investigations at the sample surface, allowing only incomplete observations. Our purpose here is to significantly advance the understanding of such problems by providing quantitative measurements of the effects of dislocation pile up and grain boundary interactions in 3D. This is accomplished throughmore » the application of differential aperture X-ray Laue micro-diffraction (DAXM) and high angular resolution electron backscatter diffraction (HR-EBSD) techniques. Our analysis demonstrates a similar strain characterization capability between DAXM and HR-EBSD and the variation of stress intensity in 3D reveals that different parts of the same grain boundary may have different strengths in resisting slip transfer, likely due to the local grain boundary curvature.« less

  20. Measurements of stress fields near a grain boundary: Exploring blocked arrays of dislocations in 3D

    SciTech Connect

    Guo, Y.; Collins, D. M.; Tarleton, E.; Hofmann, F.; Tischler, J.; Liu, W.; Xu, R.; Wilkinson, A. J.; Britton, T. B.

    2015-06-24

    The interaction between dislocation pile-ups and grain boundaries gives rise to heterogeneous stress distributions when a structural metal is subjected to mechanical loading. Such stress heterogeneity leads to preferential sites for damage nucleation and therefore is intrinsically linked to the strength and ductility of polycrystalline metals. To date the majority of conclusions have been drawn from 2D experimental investigations at the sample surface, allowing only incomplete observations. Our purpose here is to significantly advance the understanding of such problems by providing quantitative measurements of the effects of dislocation pile up and grain boundary interactions in 3D. This is accomplished through the application of differential aperture X-ray Laue micro-diffraction (DAXM) and high angular resolution electron backscatter diffraction (HR-EBSD) techniques. Our analysis demonstrates a similar strain characterization capability between DAXM and HR-EBSD and the variation of stress intensity in 3D reveals that different parts of the same grain boundary may have different strengths in resisting slip transfer, likely due to the local grain boundary curvature.

  1. Single crystalline cylindrical nanowires – toward dense 3D arrays of magnetic vortices

    NASA Astrophysics Data System (ADS)

    Ivanov, Yurii P.; Chuvilin, Andrey; Vivas, Laura G.; Kosel, Jurgen; Chubykalo-Fesenko, Oksana; Vázquez, Manuel

    2016-03-01

    Magnetic vortex-based media have recently been proposed for several applications of nanotechnology; however, because lithography is typically used for their preparation, their low-cost, large-scale fabrication is a challenge. One solution may be to use arrays of densely packed cobalt nanowires that have been efficiently fabricated by electrodeposition. In this work, we present this type of nanoscale magnetic structures that can hold multiple stable magnetic vortex domains at remanence with different chiralities. The stable vortex state is observed in arrays of monocrystalline cobalt nanowires with diameters as small as 45 nm and lengths longer than 200 nm with vanishing magnetic cross talk between closely packed neighboring wires in the array. Lorentz microscopy, electron holography and magnetic force microscopy, supported by micromagnetic simulations, show that the structure of the vortex state can be adjusted by varying the aspect ratio of the nanowires. The data we present here introduce a route toward the concept of 3-dimensional vortex-based magnetic memories.

  2. Single crystalline cylindrical nanowires - toward dense 3D arrays of magnetic vortices.

    PubMed

    Ivanov, Yurii P; Chuvilin, Andrey; Vivas, Laura G; Kosel, Jurgen; Chubykalo-Fesenko, Oksana; Vázquez, Manuel

    2016-01-01

    Magnetic vortex-based media have recently been proposed for several applications of nanotechnology; however, because lithography is typically used for their preparation, their low-cost, large-scale fabrication is a challenge. One solution may be to use arrays of densely packed cobalt nanowires that have been efficiently fabricated by electrodeposition. In this work, we present this type of nanoscale magnetic structures that can hold multiple stable magnetic vortex domains at remanence with different chiralities. The stable vortex state is observed in arrays of monocrystalline cobalt nanowires with diameters as small as 45 nm and lengths longer than 200 nm with vanishing magnetic cross talk between closely packed neighboring wires in the array. Lorentz microscopy, electron holography and magnetic force microscopy, supported by micromagnetic simulations, show that the structure of the vortex state can be adjusted by varying the aspect ratio of the nanowires. The data we present here introduce a route toward the concept of 3-dimensional vortex-based magnetic memories. PMID:27030143

  3. A Robust MEMS Based Multi-Component Sensor for 3D Borehole Seismic Arrays

    SciTech Connect

    Paulsson Geophysical Services

    2008-03-31

    The objective of this project was to develop, prototype and test a robust multi-component sensor that combines both Fiber Optic and MEMS technology for use in a borehole seismic array. The use such FOMEMS based sensors allows a dramatic increase in the number of sensors that can be deployed simultaneously in a borehole seismic array. Therefore, denser sampling of the seismic wave field can be afforded, which in turn allows us to efficiently and adequately sample P-wave as well as S-wave for high-resolution imaging purposes. Design, packaging and integration of the multi-component sensors and deployment system will target maximum operating temperature of 350-400 F and a maximum pressure of 15000-25000 psi, thus allowing operation under conditions encountered in deep gas reservoirs. This project aimed at using existing pieces of deployment technology as well as MEMS and fiber-optic technology. A sensor design and analysis study has been carried out and a laboratory prototype of an interrogator for a robust borehole seismic array system has been assembled and validated.

  4. A microfabricated magnetic actuation device for mechanical conditioning of arrays of 3D microtissues.

    PubMed

    Xu, Fan; Zhao, Ruogang; Liu, Alan S; Metz, Tristin; Shi, Yu; Bose, Prasenjit; Reich, Daniel H

    2015-06-01

    This paper describes an approach to actuate magnetically arrays of microtissue constructs for long-term mechanical conditioning and subsequent biomechanical measurements. Each construct consists of cell/matrix material self-assembled around a pair of flexible poly(dimethylsiloxane) (PDMS) pillars. The deflection of the pillars reports the tissues' contractility. Magnetic stretching of individual microtissues via magnetic microspheres mounted on the cantilevers has been used to elucidate the tissues' elastic modulus and response to varying mechanical boundary conditions. This paper describes the fabrication of arrays of micromagnetic structures that can transduce an externally applied uniform magnetic field to actuate simultaneously multiple microtissues. These structures are fabricated on silicon-nitride coated Si wafers and contain electrodeposited Ni bars. Through-etched holes provide optical and culture media access when the devices are mounted on the PDMS microtissue scaffold devices. Both static and AC forces (up to 20 μN on each microtissue) at physiological frequencies are readily generated in external fields of 40 mT. Operation of the magnetic arrays was demonstrated via measurements of elastic modulus and dynamic stiffening in response to AC actuation of fibroblast populated collagen microtissues. PMID:25959132

  5. A microfabricated magnetic actuation device for mechanical conditioning of arrays of 3D microtissues

    PubMed Central

    Xu, Fan; Zhao, Ruogang; Liu, Alan S.; Metz, Tristin; Shi, Yu; Bose, Prasenjit; Reich, Daniel H.

    2015-01-01

    This paper describes an approach to actuate magnetically arrays of microtissue constructs for long-term mechanical conditioning and subsequent biomechanical measurements. Each construct consists of cell/matrix material self-assembled around a pair of flexible poly(dimethylsiloxane) (PDMS) pillars. The deflection of the pillars reports the tissues’ contractility. Magnetic stretching of individual microtissues via magnetic microspheres mounted on the cantilevers has been used to elucidate the tissues’ elastic modulus and response to varying mechanical boundary conditions. This paper describes the fabrication of arrays of micromagnetic structures that can transduce an externally applied uniform magnetic field to actuate simultaneously multiple microtissues. These structures are fabricated on silicon-nitride coated Si wafers and contain electrodeposited Ni bars. Through-etched holes provide optical and culture media access when the devices are mounted on the PDMS microtissue scaffold devices. Both static and AC forces (up to 20 μN on each microtissue) at physiological frequencies are readily generated in external fields of 40 mT. Operation of the magnetic arrays was demonstrated via measurements of elastic modulus and dynamic stiffening in response to AC actuation of fibroblast populated collagen microtissues. PMID:25959132

  6. Single crystalline cylindrical nanowires – toward dense 3D arrays of magnetic vortices

    PubMed Central

    Ivanov, Yurii P.; Chuvilin, Andrey; Vivas, Laura G.; Kosel, Jurgen; Chubykalo-Fesenko, Oksana; Vázquez, Manuel

    2016-01-01

    Magnetic vortex-based media have recently been proposed for several applications of nanotechnology; however, because lithography is typically used for their preparation, their low-cost, large-scale fabrication is a challenge. One solution may be to use arrays of densely packed cobalt nanowires that have been efficiently fabricated by electrodeposition. In this work, we present this type of nanoscale magnetic structures that can hold multiple stable magnetic vortex domains at remanence with different chiralities. The stable vortex state is observed in arrays of monocrystalline cobalt nanowires with diameters as small as 45 nm and lengths longer than 200 nm with vanishing magnetic cross talk between closely packed neighboring wires in the array. Lorentz microscopy, electron holography and magnetic force microscopy, supported by micromagnetic simulations, show that the structure of the vortex state can be adjusted by varying the aspect ratio of the nanowires. The data we present here introduce a route toward the concept of 3-dimensional vortex-based magnetic memories. PMID:27030143

  7. Virus enabled 3d nano-array electrodes for integrated Lithium/Sodium-ion microbatteries

    NASA Astrophysics Data System (ADS)

    Liu, Yihang

    Multilayers of functional materials (carbon/electrode/nickel) were hierarchically architectured over tobacco mosaic virus (TMV) templates that were genetically modified to self-assemble in a vertical manner on current-collectors for battery applications. The spaces formed between individual rods effectively accommodated the volume expansion and contraction of electrodes during charge/discharge, while surface carbon coating engineered over these nanorods further enhance the electronic conductivity. The microbattery based on self aligned nanoforests with precise arrangement of various auxiliary material layers including a central nanometric metal core as direct electronic pathway to current collector, can deliver high energy density and stable cycling stability. C/LiFePO4/Ni/TMV nanoforest cathodes for Li-ion batteries and C/Sn/Ni/TMV nanoforest anodes for Na-ion batteries were assembled using physical sputtering deposition. Both 3D nanoforest electrodes show exceptional cycling stability and rate capability.

  8. Fabrication of corner cube array retro-reflective structure with DLP-based 3D printing technology

    NASA Astrophysics Data System (ADS)

    Riahi, Mohammadreza

    2016-06-01

    In this article, the fabrication of a corner cube array retro-reflective structure is presented by using DLP-based 3D printing technology. In this additive manufacturing technology a pattern of a cube corner array is designed in a computer and sliced with specific software. The image of each slice is then projected from the bottom side of a reservoir, containing UV cure resin, utilizing a DLP video projector. The projected area is cured and attached to a base plate. This process is repeated until the entire part is made. The best orientation of the printing process and the effect of layer thicknesses on the surface finish of the cube has been investigated. The thermal reflow surface finishing and replication with soft molding has also been presented in this article.

  9. Fabrication of corner cube array retro-reflective structure with DLP-based 3D printing technology

    NASA Astrophysics Data System (ADS)

    Riahi, Mohammadreza

    2016-04-01

    In this article, the fabrication of a corner cube array retro-reflective structure is presented by using DLP-based 3D printing technology. In this additive manufacturing technology a pattern of a cube corner array is designed in a computer and sliced with specific software. The image of each slice is then projected from the bottom side of a reservoir, containing UV cure resin, utilizing a DLP video projector. The projected area is cured and attached to a base plate. This process is repeated until the entire part is made. The best orientation of the printing process and the effect of layer thicknesses on the surface finish of the cube has been investigated. The thermal reflow surface finishing and replication with soft molding has also been presented in this article.

  10. Biologically relevant 3D tumor arrays: treatment response and the importance of stromal partners

    NASA Astrophysics Data System (ADS)

    Rizvi, Imran; Celli, Jonathan P.; Xu, Feng; Evans, Conor L.; Abu-Yousif, Adnan O.; Muzikansky, Alona; Elrington, Stefan A.; Pogue, Brian W.; Finkelstein, Dianne M.; Demirci, Utkan; Hasan, Tayyaba

    2011-02-01

    The development and translational potential of therapeutic strategies for cancer is limited, in part, by a lack of biological models that capture important aspects of tumor growth and treatment response. It is also becoming increasingly evident that no single treatment will be curative for this complex disease. Rationally-designed combination regimens that impact multiple targets provide the best hope of significantly improving clinical outcomes for cancer patients. Rapidly identifying treatments that cooperatively enhance treatment efficacy from the vast library of candidate interventions is not feasible, however, with current systems. There is a vital, unmet need to create cell-based research platforms that more accurately mimic the complex biology of human tumors than monolayer cultures, while providing the ability to screen therapeutic combinations more rapidly than animal models. We have developed a highly reproducible in vitro three-dimensional (3D) tumor model for micrometastatic ovarian cancer (OvCa), which in conjunction with quantitative image analysis routines to batch-process large datasets, serves as a high throughput reporter to screen rationally-designed combination regimens. We use this system to assess mechanism-based combination regimens with photodynamic therapy (PDT), which sensitizes OvCa to chemo and biologic agents, and has shown promise in clinic trials. We show that PDT synergistically enhances carboplatin efficacy in a sequence dependent manner. In printed heterocellular cultures we demonstrate that proximity of fibroblasts enhances 3D tumor growth and investigate co-cultures with endothelial cells. The principles described here could inform the design and evaluation of mechanism-based therapeutic options for a broad spectrum of metastatic solid tumors.

  11. 3-Dimensional Terraced NAND (3D TNAND) Flash Memory-Stacked Version of Folded NAND Array

    NASA Astrophysics Data System (ADS)

    Kim, Yoon; Cho, Seongjae; Lee, Gil Sung; Park, Il Han; Lee, Jong Duk; Shin, Hyungcheol; Park, Byung-Gook

    We propose a 3-dimensional terraced NAND flash memory. It has a vertical channel so it is possible to make a long enough channel in 1F2 size. And it has 3-dimensional structure whose channel is connected vertically along with two stairs. So we can obtain high density as in the stacked array structure, without silicon stacking process. We can make NAND flash memory with 3F2 cell size. Using SILVACO ATLAS simulation, we study terraced NAND flash memory characteristics such as program, erase, and read. Also, its fabrication method is proposed.

  12. Scalable Fluidic Injector Arrays for Viral Targeting of Intact 3-D Brain Circuits

    PubMed Central

    Chan, Stephanie; Bernstein, Jacob; Boyden, Edward

    2010-01-01

    Our understanding of neural circuits--how they mediate the computations that subserve sensation, thought, emotion, and action, and how they are corrupted in neurological and psychiatric disorders--would be greatly facilitated by a technology for rapidly targeting genes to complex 3-dimensional neural circuits, enabling fast creation of "circuit-level transgenics." We have recently developed methods in which viruses encoding for light-sensitive proteins can sensitize specific cell types to millisecond-timescale activation and silencing in the intact brain. We here present the design and implementation of an injector array capable of delivering viruses (or other fluids) to dozens of defined points within the 3-dimensional structure of the brain (Figure. 1A, 1B). The injector array comprises one or more displacement pumps that each drive a set of syringes, each of which feeds into a polyimide/fused-silica capillary via a high-pressure-tolerant connector. The capillaries are sized, and then inserted into, desired locations specified by custom-milling a stereotactic positioning board, thus allowing viruses or other reagents to be delivered to the desired set of brain regions. To use the device, the surgeon first fills the fluidic subsystem entirely with oil, backfills the capillaries with the virus, inserts the device into the brain, and infuses reagents slowly (<0.1 microliters/min). The parallel nature of the injector array facilitates rapid, accurate, and robust labeling of entire neural circuits with viral payloads such as optical sensitizers to enable light-activation and silencing of defined brain circuits. Along with other technologies, such as optical fiber arrays for light delivery to desired sets of brain regions, we hope to create a toolbox that enables the systematic probing of causal neural functions in the intact brain. This technology may not only open up such systematic approaches to circuit-focused neuroscience in mammals, and facilitate labeling of

  13. Characterization of a 3D optrode array for infrared neural stimulation

    PubMed Central

    Abaya, T.V.F.; Diwekar, M.; Blair, S.; Tathireddy, P.; Rieth, L.; Clark, G.A.; Solzbacher, F.

    2012-01-01

    This paper characterizes the Utah Slant Optrode Array (USOA) as a means to deliver infrared light deep into tissue. An undoped crystalline silicon (100) substrate was used to fabricate 10 × 10 arrays of optrodes with rows of varying lengths from 0.5 mm to 1.5 mm on a 400-μm pitch. Light delivery from optical fibers and loss mechanisms through these Si optrodes were characterized, with the primary loss mechanisms being Fresnel reflection, coupling, radiation losses from the tapered shank and total internal reflection in the tips. Transmission at the optrode tips with different optical fiber core diameters and light in-coupling interfaces was investigated. At λ = 1.55μm, the highest optrode transmittance of 34.7%, relative to the optical fiber output power, was obtained with a 50-μm multi-mode fiber butt-coupled to the optrode through an intervening medium of index n = 1.66. Maximum power is directed into the optrodes when using fibers with core diameters of 200 μm or less. In addition, the output power varied with the optrode length/taper such that longer and less tapered optrodes exhibited higher light transmission efficiency. Output beam profiles and potential impacts on physiological tests were also examined. Future work is expected to improve USOA efficiency to greater than 64%. PMID:23024914

  14. The directed cooperative assembly of proteorhodopsin into 2D and 3D polarized arrays

    PubMed Central

    Liang, Hongjun; Whited, Gregg; Nguyen, Chi; Stucky, Galen D.

    2007-01-01

    Proteorhodopsin is the membrane protein used by marine bacterioplankton as a light-driven proton pump. Here, we describe a rapid cooperative assembly process directed by universal electrostatic interactions that spontaneously organizes proteorhodopsin molecules into ordered arrays with well defined orientation and packing density. We demonstrate the charge density-matching mechanism that selectively controls the assembly process. The interactions among different components in the system are tuned by varying their charge densities to yield different organized transmembrane protein arrays: (i) a bacteriorhodopsin purple membrane-like structure where proteorhodopsin molecules are cooperatively arranged with charged lipids into a 2D hexagonal lattice; (ii) selected liquid-crystalline states in which crystalline lamellae made up of the coassembled proteorhodopsin and charged lipid molecules are coupled three-dimensionally with polarized proteorhodopsin orientation persisting through the macroscopic scale. Understanding this rapid electrostatically driven assembly process sheds light on organizing membrane proteins in general, which is a prerequisite for membrane protein structural and mechanistic studies as well as in vitro applications. PMID:17488827

  15. Lithographic VCSEL array multimode and single mode sources for sensing and 3D imaging

    NASA Astrophysics Data System (ADS)

    Leshin, J.; Li, M.; Beadsworth, J.; Yang, X.; Zhang, Y.; Tucker, F.; Eifert, L.; Deppe, D. G.

    2016-05-01

    Sensing applications along with free space data links can benefit from advanced laser sources that produce novel radiation patterns and tight spectral control for optical filtering. Vertical-cavity surface-emitting lasers (VCSELs) are being developed for these applications. While oxide VCSELs are being produced by most companies, a new type of oxide-free VCSEL is demonstrating many advantages in beam pattern, spectral control, and reliability. These lithographic VCSELs offer increased power density from a given aperture size, and enable dense integration of high efficiency and single mode elements that improve beam pattern. In this paper we present results for lithographic VCSELs and describes integration into military systems for very low cost pulsed applications, as well as continuouswave applications in novel sensing applications. The VCSELs are being developed for U.S. Army for soldier weapon engagement simulation training to improve beam pattern and spectral control. Wavelengths in the 904 nm to 990 nm ranges are being developed with the spectral control designed to eliminate unwanted water absorption bands from the data links. Multiple beams and radiation patterns based on highly compact packages are being investigated for improved target sensing and transmission fidelity in free space data links. These novel features based on the new VCSEL sources are also expected to find applications in 3-D imaging, proximity sensing and motion control, as well as single mode sensors such as atomic clocks and high speed data transmission.

  16. 3D-Printed Microwell Arrays for Ciona Microinjection and Timelapse Imaging

    PubMed Central

    Gregory, Clint; Veeman, Michael

    2013-01-01

    Ascidians such as Ciona are close chordate relatives of the vertebrates with small, simple embryonic body plans and small, simple genomes. The tractable size of the embryo offers considerable advantages for in toto imaging and quantitative analysis of morphogenesis. For functional studies, Ciona eggs are considerably more challenging to microinject than the much larger eggs of other model organisms such as zebrafish and Xenopus. One of the key difficulties is in restraining the eggs so that the microinjection needle can be easily introduced and withdrawn. Here we develop and test a device to cast wells in agarose that are each sized to hold a single egg. This injection mold is fabricated by micro-resolution stereolithography with a grid of egg-sized posts that cast corresponding wells in agarose. This 3D printing technology allows the rapid and inexpensive testing of iteratively refined prototypes. In addition to their utility in microinjection, these grids of embryo-sized wells are also valuable for timelapse imaging of multiple embryos. PMID:24324769

  17. Automated quantitative analysis of 3D morphology and mean corpuscular hemoglobin in human red blood cells stored in different periods.

    PubMed

    Moon, Inkyu; Yi, Faliu; Lee, Yeon H; Javidi, Bahram; Boss, Daniel; Marquet, Pierre

    2013-12-16

    Quantitative phase (QP) images of red blood cells (RBCs), which are obtained by off-axis digital holographic microscopy, can provide quantitative information about three-dimensional (3D) morphology of human RBCs and the characteristic properties such as mean corpuscular hemoglobin (MCH) and MCH surface density (MCHSD). In this paper, we investigate modifications of the 3D morphology and MCH in RBCs induced by the period of storage time for the purpose of classification of RBCs with different periods of storage by using off-axis digital holographic microscopy. The classification of RBCs based on the duration of storage is highly relevant because a long storage of blood before transfusion may alter the functionality of RBCs and, therefore, cause complications in patients. To analyze any changes in the 3D morphology and MCH of RBCs due to storage, we use data sets from RBC samples stored for 8, 13, 16, 23, 27, 30, 34, 37, 40, 47, and 57 days, respectively. The data sets consist of more than 3,300 blood cells in eleven classes, with more than 300 blood cells per class. The classes indicate the storage period of RBCs and are listed in chronological order. Using the RBCs donated by healthy persons, the off-axis digital holographic microscopy reconstructs several quantitative phase images of RBC samples stored for eleven different periods. We employ marker-controlled watershed transform to remove the background in the RBC quantitative phase images obtained by the off-axis digital holographic microscopy. More than 300 single RBCs are extracted from the segmented quantitative phase images for each class. Such a large number of RBC samples enable us to obtain statistical distributions of the characteristic properties of RBCs after a specific period of storage. Experimental results show that the 3D morphology of the RBCs, in contrast to MCH, is essentially related to the aging of the RBCs. PMID:24514667

  18. 3-D EM inversion of ground based geomagnetic Sq data. Results from the analysis of Australian array (AWAGS) data

    NASA Astrophysics Data System (ADS)

    Koch, Stephan; Kuvshinov, Alexey

    2015-03-01

    We present the first inversion of geomagnetic Sq data in a framework of 3-D conductivity models. This problem has been considered as immensely difficult due to the complex spatial structure of the Sq source which, in addition, varies with season and solar activity. Recently, we developed a 3-D electromagnetic (EM) inversion solution that allows one to work in a consistent manner with data that originates from sources, irrespective of their spatial complexity. In this paper, we apply our 3-D EM inversion scheme to Sq data collected during the Australian Wide Array of Geomagnetic Stations project. Within this project, three components of the geomagnetic field were recorded between 1989 November and 1990 December with the use of 53 portable vector magnetometers. The instruments were distributed over the Australian mainland with an average spacing of 275 km between sites. Inverting this unique-in a sense of its spatial regularity, density and long operational time-data set, we recovered the 3-D conductivity distribution beneath Australia at upper mantle depths (100-520 km). This depth range was justified in the paper from resolution studies using checkerboard tests. In addition, we performed extensive modelling to estimate quantitatively the influence of various factors on Sq signals, namely from hypothetical anomalies, inaccuracy in the source, ocean, and model discretization. As expected, the ocean (coastal) effect appeared to be the largest so that it has to be accounted for during 3-D inversion as accurately as possible. Our 3-D inversions-of data from either single or multiple days-revealed a strong offshore conductor near the south-east coast of Australia, which persists at all considered depths. Varying in details, this anomaly is remarkably robust irrespective of the considered day(s). We compared our results to those obtained from a different inversion scheme and an independent induction data set, and observed encouraging similarity. Combination of the two

  19. Single-qubit gates based on targeted phase shifts in a 3D neutral atom array.

    PubMed

    Wang, Yang; Kumar, Aishwarya; Wu, Tsung-Yao; Weiss, David S

    2016-06-24

    Although the quality of individual quantum bits (qubits) and quantum gates has been steadily improving, the number of qubits in a single system has increased quite slowly. Here, we demonstrate arbitrary single-qubit gates based on targeted phase shifts, an approach that can be applied to atom, ion, or other atom-like systems. These gates are highly insensitive to addressing beam imperfections and have little cross-talk, allowing for a dramatic scaling up of qubit number. We have performed gates in series on 48 individually targeted sites in a 40% full 5 by 5 by 5 three-dimensional array created by an optical lattice. Using randomized benchmarking, we demonstrate an average gate fidelity of 0.9962(16), with an average cross-talk fidelity of 0.9979(2) (numbers in parentheses indicate the one standard deviation uncertainty in the final digits). PMID:27339984

  20. Mini-pillar array for hydrogel-supported 3D culture and high-content histologic analysis of human tumor spheroids.

    PubMed

    Kang, Jihoon; Lee, Dong Woo; Hwang, Hyun Ju; Yeon, Sang-Eun; Lee, Moo-Yeal; Kuh, Hyo-Jeong

    2016-06-21

    Three-dimensional (3D) cancer cell culture models mimic the complex 3D organization and microenvironment of human solid tumor tissue and are thus considered as highly predictive models representing avascular tumor regions. Confocal laser scanning microscopy is useful for monitoring drug penetration and therapeutic responses in 3D tumor models; however, photonic attenuation at increasing imaging depths and limited penetration of common fluorescence tracers are significant technical challenges to imaging. Immunohistological staining would be a good alternative, but the preparation of tissue sections from rather fragile spheroids through fixing and embedding procedures is challenging. Here we introduce a novel 3 × 3 mini-pillar array chip that can be utilized for 3D cell culturing and sectioning for high-content histologic analysis. The mini-pillar array chip facilitated the generation of 3D spheroids of human cancer cells within hydrogels such as alginate, collagen, and Matrigel. As expected, visualization of the 3D distribution of calcein AM and doxorubicin by optical sectioning was limited by photonic attenuation and dye penetration. The integrity of the 3D microtissue section was confirmed by immunostaining on paraffin sections and cryo-sections. The applicability of the mini-pillar array for drug activity evaluation was tested by measuring viability changes in spheroids exposed to anti-cancer agents, 5-fluorouracil and tirapazamine. Thus, our novel mini-pillar array platform can potentially promote high-content histologic analysis of 3D cultures and can be further optimized for field-specific needs. PMID:27194205

  1. Micromachined VLSI 3D electronics. Final report for period September 1, 2000 - March 31, 2001

    SciTech Connect

    Beetz, C.P.; Steinbeck, J.; Hsueh, K.L.

    2001-03-31

    The phase I program investigated the construction of electronic interconnections through the thickness of a silicon wafer. The novel aspects of the technology are that the length-to-width ratio of the channels is as high as 100:1, so that the minimum amount of real estate is used for contact area. Constructing a large array of these through-wafer interconnections will enable two circuit die to be coupled on opposite sides of a silicon circuit board providing high speed connection between the two.

  2. Gravity driven deterministic lateral displacement for suspended particles in a 3D obstacle array

    PubMed Central

    Du, Siqi; Drazer, German

    2016-01-01

    We present a simple modification to enhance the separation ability of deterministic lateral displacement (DLD) systems by expanding the two-dimensional nature of these devices and driving the particles into size-dependent, fully three-dimensional trajectories. Specifically, we drive the particles through an array of long cylindrical posts, such that they not only move parallel to the basal plane of the posts as in traditional two-dimensional DLD systems (in-plane motion), but also along the axial direction of the solid posts (out-of-plane motion). We show that the (projected) in-plane motion of the particles is completely analogous to that observed in 2D-DLD systems. In fact, a theoretical model originally developed for force-driven, two-dimensional DLD systems accurately describes the experimental results. More importantly, we analyze the particles out-of-plane motion and observe, for certain orientations of the driving force, significant differences in the out-of-plane displacement depending on particle size. Therefore, taking advantage of both the in-plane and out-of-plane motion of the particles, it is possible to achieve the simultaneous fractionation of a polydisperse suspension into multiple streams. PMID:27526935

  3. Gravity driven deterministic lateral displacement for suspended particles in a 3D obstacle array.

    PubMed

    Du, Siqi; Drazer, German

    2016-01-01

    We present a simple modification to enhance the separation ability of deterministic lateral displacement (DLD) systems by expanding the two-dimensional nature of these devices and driving the particles into size-dependent, fully three-dimensional trajectories. Specifically, we drive the particles through an array of long cylindrical posts, such that they not only move parallel to the basal plane of the posts as in traditional two-dimensional DLD systems (in-plane motion), but also along the axial direction of the solid posts (out-of-plane motion). We show that the (projected) in-plane motion of the particles is completely analogous to that observed in 2D-DLD systems. In fact, a theoretical model originally developed for force-driven, two-dimensional DLD systems accurately describes the experimental results. More importantly, we analyze the particles out-of-plane motion and observe, for certain orientations of the driving force, significant differences in the out-of-plane displacement depending on particle size. Therefore, taking advantage of both the in-plane and out-of-plane motion of the particles, it is possible to achieve the simultaneous fractionation of a polydisperse suspension into multiple streams. PMID:27526935

  4. Electromagnetic mini arrays (EMMA project). 3D modeling/inversion for mantle conductivity in the Archaean of the Fennoscandian Shield

    NASA Astrophysics Data System (ADS)

    Smirnov, M. Yu.; Korja, T.; Pedersen, L. B.

    2009-04-01

    Two electromagnetic arrays are used in the EMMA project to study conductivity structure of the Archaean lithosphere in the Fennoscandian Shield. The first array was operated during almost one year, while the second one was running only during the summer time. Twelve 5-components magnetotelluric instruments with fluxgate magnetometers recorded simultaneously time variations of Earth's natural electromagnetic field at the sites separated by c. 30 km. To better control the source field and to obtain galvanic distortion free responses we have applied horizontal spatial gradient (HSG) technique to the data. The study area is highly inhomogeneous, thus classical HSG might give erroneous results. The method was extended to include anomalous field effects by implementing multivariate analysis. The HSG transfer functions were then used to control static shift distortions of apparent resistivities. During the BEAR experiment 1997-2002, the conductance map of entire Fennoscandia was assembled and finally converted into 3D volume resistivity model. We have used the model, refined it to get denser grid around measurement area and calculated MT transfer functions after 3D modeling. We have used trial-and-error method in order to further improve the model. The data set was also inverted using 3D code of Siripunvaraporn (2005). In the first stage we have used homogeneous halfspace as starting model for the inversion. In the next step we have used final 3D forward model as apriori model. The usage of apriori information significantly stabilizes the inverse solution, especially in case of a limited amount of data available. The results show that in the Archaean Domain a conductive layer is found in the upper/middle crust on contrary to previous results from other regions of the Archaean crust in the Fennoscandian Shield. Data also suggest enhanced conductivity at the depth of c. 100 km. Conductivity below the depth of 200-250 km is lower than that of the laboratory based estimates

  5. Optimized design of a LED-array-based TOF range imaging sensor for fast 3-D shape measurement

    NASA Astrophysics Data System (ADS)

    Wang, Huanqin; Wang, Ying; Xu, Jun; He, Deyong; Zhao, Tianpeng; Ming, Hai; Kong, Deyi

    2011-06-01

    A LED-array-based range imaging sensor using Time-of-Flight (TOF) distance measurement was developed to capture the depth information of three-dimensional (3-D) object. By time-division electronic scanning of the LED heterodyne phase-shift TOF range finders in array, the range images were fast obtained without any mechanical moving parts. The design of LED-array-based range imaging sensor was adequately described and a range imaging theoretical model based on photoelectric signal processing was built, which showed there was mutual restriction relationship among the measurement time of a depth pixel, the bandwidth of receiver and the sensor's signal-to-noise ratio (SNR). In order to improve the key parameters of sensor such as range resolution and measurement speed simultaneously, some optimized designs needed to be done for the proposed range imaging sensor, including choosing proper parameters for the filters in receiver, adopting special structure feedback automatic gain control (AGC) circuit with short response time, etc. The final experiment results showed the sensor after optimization could acquire the range images at a rate of 10 frames per second with a range resolution as high as +/-2mm in the range of 50-1200mm. The essential advantages of the proposed range imaging sensor were construction with simple structure, high range resolution, short measurement time and low cost, which was sufficient for many robotic and industrial automation applications.

  6. Portable, Easy-to-Operate, and Antifouling Microcapsule Array Chips Fabricated by 3D Ice Printing for Visual Target Detection.

    PubMed

    Zhang, Hong-Ze; Zhang, Fang-Ting; Zhang, Xiao-Hui; Huang, Dong; Zhou, Ying-Lin; Li, Zhi-Hong; Zhang, Xin-Xiang

    2015-06-16

    Herein, we proposed a portable, easy-to-operate, and antifouling microcapsule array chip for target detection. This prepackaged chip was fabricated by innovative and cost-effective 3D ice printing integrating with photopolymerization sealing which could eliminate complicated preparation of wet chemistry and effectively resist outside contaminants. Only a small volume of sample (2 μL for each microcapsule) was consumed to fulfill the assay. All the reagents required for the analysis were stored in ice form within the microcapsule before use, which guaranteed the long-term stability of microcapsule array chips. Nitrite and glucose were chosen as models for proof of concept to achieve an instant quantitative detection by naked eyes without the need of external sophisticated instruments. The simplicity, low cost, and small sample consumption endowed ice-printing microcapsule array chips with potential commercial value in the fields of on-site environmental monitoring, medical diagnostics, and rapid high-throughput point-of-care quantitative assay. PMID:25970032

  7. 3-D Simulation of a prototype pump-turbine during starting period in turbine model

    NASA Astrophysics Data System (ADS)

    Chen, T. J.; Luo, X. Q.; Guo, P. C.; Wu, Y. L.

    2013-12-01

    Three dimensional (3-D), unsteady flows in a prototype pump-turbine during a transient process of start-up at no load condition were studied using the computational fluid dynamics method. The fluid coupling and DM method were used to calculate the rotational speed for each time step. The dynamic mesh (DM) method and remeshing method were applied to simulate the rotation of guide vanes. Calculations were performed based on the bar v2-f turbulence model, and the calculation results were compared and verified by experimental data. Transient explicit characteristics such as the flow-rate, head, torque of the runner etc., as well as the internal flow during the start-up were analyzed. The amplitude of pressure fluctuation was larger as the rotational speed of runner increased. The pump-turbine was more unstable with the decrease of the moment of inertia. The impact jet flow in the runner has a direct relationship with the increase of the torque of runner. No stall phenomenon in the runner when the pump-turbine runs close to no load opening condition. This calculation was based on a prototype of a pumped storage power station and the computational method could be used in the fault diagnosis of transient operation.

  8. Unequal-period combination approach of gray code and phase-shifting for 3-D visual measurement

    NASA Astrophysics Data System (ADS)

    Yu, Shuang; Zhang, Jing; Yu, Xiaoyang; Sun, Xiaoming; Wu, Haibin

    2016-09-01

    Combination of Gray code and phase-shifting is the most practical and advanced approach for the structured light 3-D measurement so far, which is able to measure objects with complex and discontinuous surface. However, for the traditional combination of the Gray code and phase-shifting, the captured Gray code images are not always sharp cut-off in the black-white conversion boundaries, which may lead to wrong decoding analog code orders. Moreover, during the actual measurement, there also exists local decoding error for the wrapped analog code obtained with the phase-shifting approach. Therefore, for the traditional approach, the wrong analog code orders and the local decoding errors will consequently introduce the errors which are equivalent to a fringe period when the analog code is unwrapped. In order to avoid one-fringe period errors, we propose an approach which combines Gray code with phase-shifting according to unequal period. With theoretical analysis, we build the measurement model of the proposed approach, determine the applicable condition and optimize the Gray code encoding period and phase-shifting fringe period. The experimental results verify that the proposed approach can offer a reliable unwrapped analog code, which can be used in 3-D shape measurement.

  9. Novel polythreaded coordination polymer: from an armed-polyrotaxane sheet to a 3D polypseudorotaxane array, photo- and thermochromic behaviors.

    PubMed

    Yao, Qing-Xia; Ju, Zhan-Feng; Jin, Xu-Hui; Zhang, Jie

    2009-02-16

    A novel coordination compound, {[Cd(BDC)(Bpybc)(1.5)].10H(2)O}(n), obtained by the reaction of CdCl(2) with 1,1'-bis(4-carboxybenzyl)-4,4'-bipyridinium dichloride (H(2)BpybcCl(2)) and 1,4-benzenedicarboxylic acid (H(2)BDC), contains 1D polymeric chains that are comprised of alternating rings and rods and dangling lateral arms. These 1D polymeric motifs are interlaced via rotaxane-like mechanical linkages to give 2D armed-polyrotaxane sheets, which are further mutually polythreaded via pseudorotaxane-like mechanical linkages to form a 3D polypseudorotaxane array. Notably, a sandwich-type donor-acceptor-donor stacking is formed within each ring as a consequence of both types of polythreading in this species, and photoinduced and thermal-induced reduction of bipyridinium occurs with a color change from light yellow to blue. PMID:19166285

  10. Biologically relevant 3D tumor arrays: imaging-based methods for quantification of reproducible growth and analysis of treatment response

    NASA Astrophysics Data System (ADS)

    Celli, Jonathan P.; Rizvi, Imran; Blanden, Adam R.; Abu-Yousif, Adnan O.; Spring, Bryan Q.; Hasan, Tayyaba

    2011-02-01

    Three-dimensional in vitro tumor models have emerged as powerful research tools in cancer biology, though the vast potential of these systems as high-throughput, biologically relevant reporters of treatment response has yet to be adequately explored. Here, building on previous studies, we demonstrate the utility of using 3D models for ovarian and pancreatic cancers in conjunction with quantitative image processing to reveal aspects of growth behavior and treatment response that would not be evident without either modeling or quantitative analysis component. In this report we specifically focus on recent improvements in the imaging component of this integrative research platform and emphasize analysis to establish reproducible growth properties in 3D tumor arrays, a key consideration in establishing the utility of this platform as a reliable reporter of therapeutic response. Building on previous studies using automated segmentation of low magnification image fields containing large numbers of nodules to study size dependent treatment effects, we introduce an improvement to this method using multiresolution decomposition to remove gradient background from transmitted light images for more reliable feature identification. This approach facilitates the development of a new treatment response metric, disruption fraction (Dfrac), which quantifies dose dependent distribution shifts from nodular fragmentation induced by cytotoxic therapies. Using this approach we show that PDT treatment is associated with significant dose-dependent increases in Dfrac, while this is not observed with carboplatin treatment. The ability to quantify this response to therapy could play a key role in design of combination regimens involving these two modalities.

  11. 3D nanoimprint for NIR Fabry-Pérot filter arrays: fabrication, characterization and comparison of different cavity designs

    NASA Astrophysics Data System (ADS)

    Nguyen, Duc Toan; Ababtain, Muath; Memon, Imran; Ullah, Anayat; Istock, André; Woidt, Carsten; Xie, Weichang; Lehmann, Peter; Hillmer, Hartmut

    2016-02-01

    We report on the fabrication of miniaturized NIR spectrometers based on arrays of multiple Fabry-Pérot (FP) filters. The various cavities of different height are fabricated via a single patterning step using high resolution 3D nanoimprint technology. Today, low-cost patterning of extended cavity heights for NIR filters using the conventional spin-coated nanoimprint methodology is not available because of insufficient coating layers and low mobility of the resist materials to fill extended cavity structures. Our investigation focuses on reducing the technological effort for fabrication of homogeneous extended cavities. We study alternative cavity designs, including a new resist and apply large-area 3D nanoimprint based on hybrid mold and UV Substrate Conformal Imprint Lithography (UV-SCIL) to overcome these limitations. We compare three different solutions, i.e. (1) applying multiple spin coating of the resist to obtain thicker initial resist layers, (2) introducing a hybrid cavity (combination of a thin oxide layer and the organic cavity) to compensate the height differences, and (3) optimizing the imprint process with a novel resist material. The imprint results based on these methods demonstrate the implementation of NIR FP filters with high transmission intensity (best single filter transmission >90 %) and small line widths (<5 nm in full width at half maximum).

  12. Real-time 3D millimeter wave imaging based FMCW using GGD focal plane array as detectors

    NASA Astrophysics Data System (ADS)

    Levanon, Assaf; Rozban, Daniel; Kopeika, Natan S.; Yitzhaky, Yitzhak; Abramovich, Amir

    2014-03-01

    Millimeter wave (MMW) imaging systems are required for applications in medicine, communications, homeland security, and space technology. This is because there is no known ionization hazard for biological tissue, and atmospheric attenuation in this range of the spectrum is relatively low. The lack of inexpensive room temperature imaging systems makes it difficult to give a suitable MMW system for many of the above applications. 3D MMW imaging system based on chirp radar was studied previously using a scanning imaging system of a single detector. The system presented here proposes to employ a chirp radar method with a Glow Discharge Detector (GDD) Focal Plane Array (FPA) of plasma based detectors. Each point on the object corresponds to a point in the image and includes the distance information. This will enable 3D MMW imaging. The radar system requires that the millimeter wave detector (GDD) will be able to operate as a heterodyne detector. Since the source of radiation is a frequency modulated continuous wave (FMCW), the detected signal as a result of heterodyne detection gives the object's depth information according to value of difference frequency, in addition to the reflectance of the image. In this work we experimentally demonstrate the feasibility of implementing an imaging system based on radar principles and FPA of GDD devices. This imaging system is shown to be capable of imaging objects from distances of at least 10 meters.

  13. Outdoor sound propagation effects on aircraft detection through passive phased-array acoustic antennas: 3D numerical simulations

    NASA Astrophysics Data System (ADS)

    Roselli, Ivan; Testa, Pierluigi; Caronna, Gaetano; Barbagelata, Andrea; Ferrando, Alessandro

    2005-09-01

    The present paper describes some of the main acoustic issues connected with the SAFE-AIRPORT European Project for the development of an innovative acoustic system for the improvement of air traffic management. The system sensors are two rotating passive phased-array antennas with 512 microphones each. In particular, this study focused on the propagation of sound waves in the atmosphere and its influence on the system detection efficiency. The effects of air temperature and wind gradients on aircraft tracking were analyzed. Algorithms were implemented to correct output data errors on aircraft location due to acoustic ray deviation in 3D environment. Numerical simulations were performed using several temperature and wind profiles according to common and critical meteorological conditions. Aircraft location was predicted through 3D acoustic ray triangulation methods, taking into account variation in speed of sound waves along rays path toward each antenna. The system range was also assessed considering aircraft noise spectral emission. Since the speed of common airplanes is not negligible with respect to sound speed during typical airport operations such as takeoff and approach, the influence of the Doppler effect on range calculation was also considered and most critical scenarios were simulated.

  14. Comparison of 1D stagnation solutions to 3D wire-array Z pinch simulations in absence of radiation

    NASA Astrophysics Data System (ADS)

    Yu, Edmund; Velikovich, Alexander; Maron, Yitzhak

    2013-10-01

    In the idealized picture of a Z pinch, a cylindrically symmetric plasma shell implodes towards axis. In this 1D (radial) picture, the resulting stagnation is very efficient: all the kinetic energy of the shell converts to internal energy, as for instance in the Noh shock solution or the homogeneous stagnation flow. If we generalize the problem to 2D by deforming the shell from perfectly circular to oblate, the resulting stagnation will not be as efficient. As in the Hiemenz flow, in which a jet of fluid strikes a rigid flat boundary and squirts out to the sides, the more complicated flows allowed in 2D allow flow kinetic energy to redirect rather than stagnate. With this picture in mind, we might expect the stagnation of a wire-array Z pinch, which in actuality forms a highly distorted 3D imploding plasma, to dissipate its kinetic energy inefficiently due to the lack of symmetry, and be indescribable by means of the idealized 1D stagnation solutions. On the other hand, one might expect that if the imploding plasma is sufficiently messy, the non-uniformities might ``wash out,'' allowing a quasi-1D description of the averaged quantities of plasma. In this work we explore this idea, comparing predictions of 1D stagnation solutions with 3D simulation. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under contract DE-AC0 4-94AL85000.

  15. Handy Compton camera using 3D position-sensitive scintillators coupled with large-area monolithic MPPC arrays

    NASA Astrophysics Data System (ADS)

    Kataoka, J.; Kishimoto, A.; Nishiyama, T.; Fujita, T.; Takeuchi, K.; Kato, T.; Nakamori, T.; Ohsuka, S.; Nakamura, S.; Hirayanagi, M.; Adachi, S.; Uchiyama, T.; Yamamoto, K.

    2013-12-01

    The release of radioactive isotopes (mainly 137Cs, 134Cs and 131I) from the crippled Fukushima Daiichi Nuclear Plant remains a serious problem in Japan. To help identify radiation hotspots and ensure effective decontamination operation, we are developing a novel Compton camera weighting only 1 kg and measuring just ∼10 cm2 in size. Despite its compactness, the camera realizes a wide 180° field of vision with a sensitivity about 50 times superior to other cameras being tested in Fukushima. We expect that a hotspot producing a 5 μSv/h dose at a distance of 3 m can be imaged every 10 s, with angular resolution better than 10° (FWHM). The 3D position-sensitive scintillators and thin monolithic MPPC arrays are the key technologies developed here. By measuring the pulse-height ratio of MPPC-arrays coupled at both ends of a Ce:GAGG scintillator block, the depth of interaction (DOI) is obtained for incident gamma rays as well as the usual 2D positions, with accuracy better than 2 mm. By using two identical 10 mm cubic Ce:GAGG scintillators as a scatterer and an absorber, we confirmed that the 3D configuration works well as a high-resolution gamma camera, and also works as spectrometer achieving typical energy resolution of 9.8% (FWHM) for 662 keV gamma rays. We present the current status of the prototype camera (weighting 1.5 kg and measuring 8.5×14×16 cm3 in size) being fabricated by Hamamatsu Photonics K.K. Although the camera still operates in non-DOI mode, angular resolution as high as 14° (FWHM) was achieved with an integration time of 30 s for the assumed hotspot described above.

  16. SU-F-BRE-06: Evaluation of Patient CT Dose Reconstruction From 3D Diode Array Measurements Using Anthropomorphic Phantoms

    SciTech Connect

    Huang, M; Benhabib, S; Cardan, R; Brezovich, I; Popple, R; Faught, A; Followill, D

    2014-06-15

    Purpose: To compare 3D reconstructed dose of IMRT plans from 3D diode array measurements with measurements in anthropomorphic phantoms. Methods: Six IMRT plans were created for the IROC Houston (RPC) head and neck (H and N) and lung phantoms following IROC Houston planning protocols. The plans included flattened and unflattened beam energies ranging from 6 MV to 15 MV and both static and dynamic MLC tecH and Niques. Each plan was delivered three times to the respective anthropomorphic phantom, each of which contained thermoluminescent dosimeters (TLDs) and radiochromic films (RCFs). The plans were also delivered to a Delta4 diode array (Scandidos, Uppsala, Sweden). Irradiations were done using a TrueBeam STx (Varian Medical Systems, Palo Alto, CA). The dose in the patient was calculated by the Delta4 software, which used the diode measurements to estimate incident energy fluence and a kernel-based pencil beam algorithm to calculate dose. The 3D dose results were compared with the TLD and RCF measurements. Results: In the lung, the average difference between TLDs and Delta4 calculations was 5% (range 2%–7%). For the H and N, the average differences were 2.4% (range 0%–4.5%) and 1.1% (range 0%–2%) for the high- and low-dose targets, respectively, and 12% (range 10%-13%) for the organ-at-risk simulating the spinal cord. For the RCF and criteria of 7%/4mm, 5%/3mm, and 3%/3mm, the average gamma-index pass rates were 95.4%, 85.7%, and 76.1%, respectively for the H and N and 76.2%, 57.8%, and 49.5% for the lung. The pass-rate in the lung decreased with increasing beam energy, as expected for a pencil beam algorithm. Conclusion: The H and N phantom dose reconstruction met the IROC Houston acceptance criteria for clinical trials; however, the lung phantom dose did not, most likely due to the inaccuracy of the pencil beam algorithm in the presence of low-density inhomogeneities. Work supported by PHS grant CA10953 and CA81647 (NCI, DHHS)

  17. Progress in Ring Array Transducers for Real-Time 3D Ultrasound Guidance of Cardiac Interventional Devices

    PubMed Central

    Light, Edward D.; Lieu, Victor; Suhocki, Paul; Wolf, Patrick D.; Smith, Stephen W.

    2012-01-01

    As a treatment for aortic stenosis, several companies have recently introduced prosthetic heart valves designed to be deployed through a catheter using an intravenous or trans-apical approach. This procedure can either take the place of open heart surgery with some of the devices, or delay it with others. Real-time 3D ultrasound could enable continuous monitoring of these structures before, during and after deployment. We have developed a 2D ring array integrated with a 30 French catheter that is used for trans-apical prosthetic heart valve implantation. The transducer array was built using three 46 cm long flex circuits from MicroConnex (Snoqualmie, WA) which terminate in an interconnect that plugs directly into our system cable, thus no cable soldering is required. This transducer consists of 210 elements at .157 mm inter-element spacing and operates at 5 MHz. Average measured element bandwidth was 26% and average round-trip 50 Ohm insertion loss was -81.1 dB. The transducer were wrapped around the 1 cm diameter lumen of a heart valve deployment catheter. Prosthetic heart valve images were obtained in water tank studies. PMID:21842583

  18. On the Helicity in 3D-Periodic Navier-Stokes Equations II: The Statistical Case

    NASA Astrophysics Data System (ADS)

    Foias, Ciprian; Hoang, Luan; Nicolaenko, Basil

    2009-09-01

    We study the asymptotic behavior of the statistical solutions to the Navier-Stokes equations using the normalization map [9]. It is then applied to the study of mean energy, mean dissipation rate of energy, and mean helicity of the spatial periodic flows driven by potential body forces. The statistical distribution of the asymptotic Beltrami flows are also investigated. We connect our mathematical analysis with the empirical theory of decaying turbulence. With appropriate mathematically defined ensemble averages, the Kolmogorov universal features are shown to be transient in time. We provide an estimate for the time interval in which those features may still be present. Our collaborator and friend Basil Nicolaenko passed away in September of 2007, after this work was completed. Honoring his contribution and friendship, we dedicate this article to him.

  19. Magnetic and thermodynamic properties of the 3-D periodic anderson lattice hamiltonian

    SciTech Connect

    Huscrot, C.; McMahan, A. K.; Pollock, E. I; Scalettar, R. T.

    1998-09-10

    Tight-binding models capture many of the qualitative features of interaction-induced effects in solids. For example, the simplest such model, the single-band Hubbard Hamiltonian, describes the Mott insulating phase which occurs in correlated systems, despite the fact that the one electron band is nominally only half-filled, as well as the tendency towards magnetic order. Both phenomena occur in the transition metal oxides. The Periodic Anderson Model (PAM) is a step towards incorporating more complex orbital structure. It contains a pair of orbitals on each site--a delocalized conduction band and a set of highly correlated, localized states. The PAM successfully describes conditions for transitions between antiferromagnetic order of the local moments and phases in which these moments are quenched into singlets paired with conduction electrons. These phenomena are central to heavy fermion systems. The pressure-induced volume collapse in Ce has also been attributed to Kondo-like quenching of the local f moments in this metal, as has been discussed in the context of the impurity Anderson Model. The authors describe Quantum Monte Carlo (QMC) calculations of the magnetic and thermodynamic properties of the PAM in three dimensions. Previous QMC studies have been reported in one and two dimensions. A focus of our attention will be on the density of states and the specific heat. The organization of this paper is as follows. They first introduce the PAM and outline some of its properties. Next, a brief presentation of the Quantum Monte Carlo, Maximum Entropy, and Hartree-Fock methods is given. They then show the equilibrium magnetic properties of the PAM, including the spin correlations between conduction and localized orbitals, and antiferromagnetic correlations in the localized band, before turning to the thermodynamics and the density of states. A concluding section describes connections of this work to the problem of the rare earth volume collapse transitions.

  20. Objective Assessment and Design Improvement of a Staring, Sparse Transducer Array by the Spatial Crosstalk Matrix for 3D Photoacoustic Tomography

    PubMed Central

    Kosik, Ivan; Raess, Avery

    2015-01-01

    Accurate reconstruction of 3D photoacoustic (PA) images requires detection of photoacoustic signals from many angles. Several groups have adopted staring ultrasound arrays, but assessment of array performance has been limited. We previously reported on a method to calibrate a 3D PA tomography (PAT) staring array system and analyze system performance using singular value decomposition (SVD). The developed SVD metric, however, was impractical for large system matrices, which are typical of 3D PAT problems. The present study consisted of two main objectives. The first objective aimed to introduce the crosstalk matrix concept to the field of PAT for system design. Figures-of-merit utilized in this study were root mean square error, peak signal-to-noise ratio, mean absolute error, and a three dimensional structural similarity index, which were derived between the normalized spatial crosstalk matrix and the identity matrix. The applicability of this approach for 3D PAT was validated by observing the response of the figures-of-merit in relation to well-understood PAT sampling characteristics (i.e. spatial and temporal sampling rate). The second objective aimed to utilize the figures-of-merit to characterize and improve the performance of a near-spherical staring array design. Transducer arrangement, array radius, and array angular coverage were the design parameters examined. We observed that the performance of a 129-element staring transducer array for 3D PAT could be improved by selection of optimal values of the design parameters. The results suggested that this formulation could be used to objectively characterize 3D PAT system performance and would enable the development of efficient strategies for system design optimization. PMID:25875177

  1. Using Ambient Noise Data from the ALBACORE OBS Array to Determine a 3D Seismic Velocity Model Offshore Southern California

    NASA Astrophysics Data System (ADS)

    Kohler, M. D.; Bowden, D. C.; Tsai, V. C.; Weeraratne, D. S.

    2014-12-01

    The Pacific-North America plate boundary in Southern California extends far west of the coastline, and a 12-month ocean bottom seismometer (OBS) array spanned the western side of the plate boundary in order to image seismic velocities in the lithosphere. Velocities are modeled through stacked cross correlations of ambient noise data. The offshore data come primarily from the OBS array that collected 12 months of continuous data during 2010-2011, combined with Southern California Seismic Network (SCSN) station data. The cross correlations were stacked for noise correlation functions and examined using standard time- and frequency-domain methods to determine phase velocity and group velocity dispersion curves. Signals between the vertical-component OBS and co-located horizontal-component OBS observations associated with tilt noise, and pressure gauge observations associated with infragravity waves, were examined to further improve signals. The non-elastic noise was estimated by calculating the transfer functions between the vertical-to-horizontal and vertical-to-pressure components, and subtracting the coherent signal between the two from the vertical-component time series. We find that these effects are small in our dataset. We are simultaneously inverting all measureable dispersion curves to solve for 3D crustal velocity structure. Shear-wave velocities comprise the direct solution, and Vp/Vs ratios are constrained as much as the data allow. Calculations on data from 780 OBS-OBS, SCSN-SCSN, and OBS-SCSN pairs filtered around multiple narrow bands between 5 and 50 s show clear propagating waves traveling at group velocities between 1.2 and 3.5 km/s. The longer-term outcome of this work will comprise a 3D crustal and uppermost mantle velocity model with areal coverage not attainable before the deployment of the ocean bottom seismometers. The results define the transition in three dimensions from continental lithospheric structure in the near-shore region to oceanic

  2. DEVELOPMENT OF A 400 LEVEL 3C CLAMPED DOWNHOLE SEISMIC RECEIVER ARRAY FOR 3D BOREHOLE SEISMIC IMAGING OF GAS RESERVOIRS

    SciTech Connect

    Bjorn N.P Paulsson

    2002-05-01

    Borehole seismology is the highest resolution geophysical imaging technique available to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to economically do high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology is currently frustrated by the lack of the acquisition technology necessary to record the large volumes of the high frequency, high signal-to-noise-ratio borehole seismic data needed to do 3D imaging. This proposal takes direct aim at this shortcoming. P/GSI is developing a 400 level 3C clamped downhole seismic receiver array for borehole seismic 3D imaging. This array will remove the acquisition barrier to record the necessary volumes of data to do high resolution 3D VSP or 3D cross well seismic imaging. 3D VSP and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that will allow the Gas industry to take the next step in their quest for higher resolution images of the gas reservoirs. Today only a fraction of the original Oil or Gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of the detailed compartmentalization of the oil and gas reservoirs. The 400 level 3C borehole seismic receiver array will allow for economic use of 3D borehole seismic imaging for reservoir characterization and monitoring. By using 3C surface seismic or borehole seismic sources the 400 level receiver array will furthermore facilitate 9C reservoir imaging. The 9C borehole seismic data will provide P, SH and SV information for imaging of the complex deep gas reservoirs and allow quantitative prediction of the rock and the fluid types. The data quality and the data volumes from a 400 level 3C array will allow us to develop the data processing technology necessary for high resolution reservoir imaging.

  3. DEVELOPMENT OF A 400 LEVEL 3C CLAMPED DOWNHOLE SEISMIC RECEIVER ARRAY FOR 3D BOREHOLE SEISMIC IMAGING OF GAS RESERVOIRS

    SciTech Connect

    Bjorn N.P. Paulsson

    2002-09-01

    Borehole seismology is the highest resolution geophysical imaging technique available to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to economically do high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology is currently frustrated by the lack of the acquisition technology necessary to record the large volumes of the high frequency, high signal-to-noise-ratio borehole seismic data needed to do 3D imaging. This proposal takes direct aim at this shortcoming. P/GSI is developing a 400 level 3C clamped downhole seismic receiver array for borehole seismic 3D imaging. This array will remove the acquisition barrier to record the necessary volumes of data to do high resolution 3D VSP or 3D cross well seismic imaging. 3D VSP and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that will allow the Gas industry to take the next step in their quest for higher resolution images of the gas reservoirs. Today only a fraction of the original Oil or Gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of the detailed compartmentalization of the oil and gas reservoirs. The 400 level 3C borehole seismic receiver array will allow for economic use of 3D borehole seismic imaging for reservoir characterization and monitoring. By using 3C surface seismic or 3C borehole seismic sources the 400 level receiver array will furthermore facilitate 9C reservoir imaging. The 9C borehole seismic data will provide P, SH and SV information for imaging of the complex deep gas reservoirs and allow quantitative prediction of the rock and the fluid types. The data quality and the data volumes from a 400 level 3C array will allow us to develop the data processing technology necessary for high resolution reservoir imaging.

  4. Flexible 3D porous CuO nanowire arrays for enzymeless glucose sensing: in situ engineered versus ex situ piled.

    PubMed

    Huang, Jianfei; Zhu, Yihua; Yang, Xiaoling; Chen, Wei; Zhou, Ying; Li, Chunzhong

    2015-01-14

    Convenient determination of glucose in a sensitive, reliable and cost-effective way has aroused sustained research passion, bringing along assiduous investigation of high-performance electroactive nanomaterials to build enzymeless sensors. In addition to the intrinsic electrocatalytic capability of the sensing materials, electrode architecture at the microscale is also crucial for fully enhancing the performance. In this work, free-standing porous CuO nanowire (NW) was taken as a model sensing material to illustrate this point, where an in situ formed 3D CuO nanowire array (NWA) and CuO nanowires pile (NWP) immobilized with polymer binder by conventional drop-casting technique were both studied for enzymeless glucose sensing. The NWA electrode exhibited greatly promoted electrochemistry characterized by decreased overpotential for electro-oxidation of glucose and over 5-fold higher sensitivity compared to the NWP counterpart, benefiting from the binder-free nanoarray structure. Besides, its sensing performance was also satisfying in terms of rapidness, selectivity and durability. Further, the CuO NWA was utilized to fabricate a flexible sensor which showed excellent performance stability against mechanical bending. Thanks to its favorable electrode architecture, the CuO NWA is believed to offer opportunities for building high-efficiency flexible electrochemical devices. PMID:25415769

  5. Design, Fabrication and Characterization of a Low-Impedance 3D Electrode Array System for Neuro-Electrophysiology

    PubMed Central

    Kusko, Mihaela; Craciunoiu, Florea; Amuzescu, Bogdan; Halitzchi, Ferdinand; Selescu, Tudor; Radoi, Antonio; Popescu, Marian; Simion, Monica; Bragaru, Adina; Ignat, Teodora

    2012-01-01

    Recent progress in patterned microelectrode manufacturing technology and microfluidics has opened the way to a large variety of cellular and molecular biosensor-based applications. In this extremely diverse and rapidly expanding landscape, silicon-based technologies occupy a special position, given their statute of mature, consolidated, and highly accessible areas of development. Within the present work we report microfabrication procedures and workflows for 3D patterned gold-plated microelectrode arrays (MEA) of different shapes (pyramidal, conical and high aspect ratio), and we provide a detailed characterization of their physical features during all the fabrication steps to have in the end a reliable technology. Moreover, the electrical performances of MEA silicon chips mounted on standardized connector boards via ultrasound wire-bonding have been tested using non-destructive electrochemical methods: linear sweep and cyclic voltammetry, impedance spectroscopy. Further, an experimental recording chamber package suitable for in vitro electrophysiology experiments has been realized using custom-design electronics for electrical stimulus delivery and local field potential recording, included in a complete electrophysiology setup, and the experimental structures have been tested on newborn rat hippocampal slices, yielding similar performance compared to commercially available MEA equipments. PMID:23208555

  6. On the computation of long period seismograms in a 3-D earth using normal mode based approximations

    NASA Astrophysics Data System (ADS)

    Romanowicz, Barbara A.; Panning, Mark P.; Gung, Yuancheng; Capdeville, Yann

    2008-11-01

    Tomographic inversions for large-scale structure of the earth's mantle involve a forward modelling step of wave propagation through 3-D heterogeneity. Until now, most investigators have worked in the framework of the simplest theoretical assumptions, namely the infinite frequency `ray theory' in the case of body wave traveltime inversions, or the `path-average' approximation (PAVA) to normal mode perturbation theory, in the case of surface waves and long-period waveforms. As interest is shifting to mapping shorter wavelength structures, the need for a more accurate theoretical account of the interaction of seismic waves with mantle heterogeneity, coupled with improvements in path coverage, has been realized. Here we discuss different levels of approximations used in the context of normal mode perturbation theory, when modelling time domain seismic waveforms. We compare the performance of asymptotic approximations, which collapse the effects of 3-D structure onto the great circle vertical plane: the 1-D PAVA and a 2-D approximation called non-linear asymptotic coupling theory (NACT), which both are zeroth order asymptotic approximations. We then discuss how off-vertical plane effects can be introduced using higher order asymptotics. These computationally efficient approximations are compared to the linear Born formalism (BORN), which computes scattering integrals over the entire surface of the sphere. We point out some limitations of this linear formalism in the case of spatially extended anomalies, and show how that can be remedied through the introduction of a non-linear term (NBORN). All these approximations are referenced to a precise 3-D numerical computation afforded by the spectral element method. We discuss simple geometries, and explore a range of sizes of anomalies compared to the wavelength of the seismic waves considered, thus illustrating the range of validity and limitations of the various approximations considered.

  7. A Comparative Analysis for Verification of IMRT and VMAT Treatment Plans using a 2-D and 3-D Diode Array

    NASA Astrophysics Data System (ADS)

    Dance, Michael J.

    With the added complexity of current radiation treatment dose delivery modalities such as IMRT (Intensity Modulated Radiation Therapy) and VMAT (Volumetric Modulated Arc Therapy), quality assurance (QA) of these plans become multifaceted and labor intensive. To simplify the patient specific quality assurance process, 2D or 3D diode arrays are used to measure the radiation fluence for IMRT and VMAT treatments which can then be quickly and easily compared against the planned dose distribution. Because the arrays that can be used for IMRT and VMAT patient-specific quality assurance are of different geometry (planar vs. cylindrical), the same IMRT or VMAT treatment plan measured by two different arrays could lead to different measured radiation fluences, regardless of the output and performance of linear accelerator. Thus, the purpose of this study is to compare patient specific QA results as measured by the MapCHECK 2 and ArcCHECK diode arrays for the same IMRT and VMAT treatment plans to see if one diode array consistently provides a closer comparison to reference data. Six prostate and three thoracic spine IMRT treatment plans as well as three prostate and three thoracic spine VMAT treatment plans were produced. Radiotherapy plans for this study were generated using the Pinnacle TPS v9.6 (Philips Radiation Oncology Systems, Fitchburg, WI) using 6 MV, 6 MV FFF, and 10 MV x-ray beams from a Varian TrueBeam linear accelerator (Varian Medical Systems, Palo Alto, CA) with a 120-millenium multi-leaf collimator (MLC). Each IMRT and VMAT therapy plan was measured on Sun Nuclear's MapCHECK 2 and ArcCHECK diode arrays. IMRT measured data was compared with planned dose distribution using Sun Nuclear's 3DVH quality assurance software program using gamma analysis and dose-volume histograms for target volumes and critical structures comparison. VMAT arc plans measured on the MapCHECK 2 and ArcCHECK were compared using beam-by-beam analysis with the gamma evaluation method with

  8. 3D Finite Element Model for Writing Long-Period Fiber Gratings by CO2 Laser Radiation

    PubMed Central

    Coelho, João M. P.; Nespereira, Marta; Abreu, Manuel; Rebordão, José

    2013-01-01

    In the last years, mid-infrared radiation emitted by CO2 lasers has become increasing popular as a tool in the development of long-period fiber gratings. However, although the development and characterization of the resulting sensing devices have progressed quickly, further research is still necessary to consolidate functional models, especially regarding the interaction between laser radiation and the fiber's material. In this paper, a 3D finite element model is presented to simulate the interaction between laser radiation and an optical fiber and to determine the resulting refractive index change. Dependence with temperature of the main parameters of the optical fiber materials (with special focus on the absorption of incident laser radiation) is considered, as well as convection and radiation losses. Thermal and residual stress analyses are made for a standard single mode fiber, and experimental results are presented. PMID:23941908

  9. Flexible 3D porous CuO nanowire arrays for enzymeless glucose sensing: in situ engineered versus ex situ piled

    NASA Astrophysics Data System (ADS)

    Huang, Jianfei; Zhu, Yihua; Yang, Xiaoling; Chen, Wei; Zhou, Ying; Li, Chunzhong

    2014-12-01

    Convenient determination of glucose in a sensitive, reliable and cost-effective way has aroused sustained research passion, bringing along assiduous investigation of high-performance electroactive nanomaterials to build enzymeless sensors. In addition to the intrinsic electrocatalytic capability of the sensing materials, electrode architecture at the microscale is also crucial for fully enhancing the performance. In this work, free-standing porous CuO nanowire (NW) was taken as a model sensing material to illustrate this point, where an in situ formed 3D CuO nanowire array (NWA) and CuO nanowires pile (NWP) immobilized with polymer binder by conventional drop-casting technique were both studied for enzymeless glucose sensing. The NWA electrode exhibited greatly promoted electrochemistry characterized by decreased overpotential for electro-oxidation of glucose and over 5-fold higher sensitivity compared to the NWP counterpart, benefiting from the binder-free nanoarray structure. Besides, its sensing performance was also satisfying in terms of rapidness, selectivity and durability. Further, the CuO NWA was utilized to fabricate a flexible sensor which showed excellent performance stability against mechanical bending. Thanks to its favorable electrode architecture, the CuO NWA is believed to offer opportunities for building high-efficiency flexible electrochemical devices.Convenient determination of glucose in a sensitive, reliable and cost-effective way has aroused sustained research passion, bringing along assiduous investigation of high-performance electroactive nanomaterials to build enzymeless sensors. In addition to the intrinsic electrocatalytic capability of the sensing materials, electrode architecture at the microscale is also crucial for fully enhancing the performance. In this work, free-standing porous CuO nanowire (NW) was taken as a model sensing material to illustrate this point, where an in situ formed 3D CuO nanowire array (NWA) and CuO nanowires

  10. Assessing earthquake source models using 3-D forward modelling of long-period seismic data: application to the SCARDEC method

    NASA Astrophysics Data System (ADS)

    Ferreira, Ana Mg; Vallee, Martin; Charlety, Jean

    2010-05-01

    Accurate earthquake point source parameters (e.g. seismic moment, depth and focal mechanism) provide key first-order information for detailed studies of the earthquake source process and for improved seismic and tsunami hazard evaluation. In order to objectively assess the quality of seismic source models, it is important to go beyond classical resolution checks. In particular, it is desirable to apply sophisticated modelling techniques to quantify inaccuracies due to simplified theoretical formulations and/or Earth structure employed to build the source models. Moreover, it is important to verify how well the models explain data not used in their construction. In this study we assess the quality of the SCARDEC method (see joint abstracts), which is a new automated technique that retrieves simultaneously the seismic moment, focal mechanism, depth and source time functions of large earthquakes. Because the SCARDEC method is based on body-wave deconvolution using ray methods in a 1D Earth model, we test how well SCARDEC source parameters explain long-period seismic data (surface waves and normal modes). We calculate theoretical seismograms using two forward modelling techniques (full ray theory and spectral element method) to simulate the long-period seismic wavefield for the 3D Earth model S20RTS combined with the crust model CRUST2.0, and for two point source models: (i) the SCARDEC model; and (ii) the Global CMT model. We compare the synthetic seismograms with real broadband data from the FDSN for the major subduction earthquakes of the last 20 years. We show that SCARDEC source parameters explain long-period surface waves as well as Global CMT solutions. This can be explained by the fact that most of the differences between SCARDEC and Global CMT solutions are linked to correlated variations of the seismic moment and dip of the earthquakes, and it is theoretically known that for shallow earthquakes it is difficult to accurately resolve these two parameters using

  11. Mesoscopic stability and sedimentation waves in settling periodic arrays.

    PubMed

    Felderhof, B U

    2003-11-01

    The stability of a periodic array of particles settling in a viscous incompressible fluid under the influence of gravity is investigated in the framework of the point sedimentation model. The simple cubic array is unstable, but the body-centered and face-centered cubic arrays with gravity directed along one of the crystal axes are mesoscopically stable, i.e., they are stable except for very long wavelength in a certain domain of directions of the wave vector. In such mesoscopically stable arrays the instability is suppressed in periodic boundary conditions for systems smaller than a maximum size. In a stable finite system the particles perform small motions about the positions of the regular array, and sedimentation waves propagate through the system. PMID:14682796

  12. DEVELOPMENT OF A 400 LEVEL 3C CLAMPED DOWNHOLE SEISMIC RECEIVER ARRAY FOR 3D BOREHOLE SEISMIC IMAGING OF GAS RESERVOIRS

    SciTech Connect

    Bjorn N.P. Paulsson

    2004-12-31

    Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to economically do high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology is currently frustrated by the lack of the acquisition technology necessary to record the large volumes of the high frequency, high signal-to-noise-ratio borehole seismic data needed to do 3D imaging. This project takes direct aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array will remove the technical acquisition barrier for recording the necessary volumes of data to do high resolution 3D VSP or 3D cross well seismic imaging. Massive 3D VSP{reg_sign} and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that will allow the Gas industry to take the next step in their quest for higher resolution images of the gas reservoirs for the purpose of improving the recovery of the natural gas resources. Today only a fraction of the original Oil or Gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of the detailed compartmentalization of the oil and gas reservoirs. The 400 level 3C borehole seismic receiver array will allow for the economic use of 3D borehole seismic imaging for reservoir characterization and monitoring by allowing the economic recording of the required large data volumes that have a sufficiently dense spatial sampling. By using 3C surface seismic or 3C borehole seismic sources the 400 level receiver arrays will furthermore allow 3D reservoir imaging using 9C data. The 9C borehole seismic data will provide P, SH and SV information for imaging of the complex deep gas reservoirs and allow quantitative prediction of

  13. DEVELOPMENT OF A 400 LEVEL 3C CLAMPED DOWNHOLE SEISMIC RECEIVER ARRAY FOR 3D BOREHOLE SEISMIC IMAGING OF GAS RESERVOIRS

    SciTech Connect

    Bjorn N.P. Paulsson

    2005-03-31

    Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to economically do high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology is currently hampered by the lack of the acquisition technology necessary to record the large volumes of the high frequency, high signal-to-noise-ratio borehole seismic data needed to do 3D imaging. This project takes direct aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array will remove the technical acquisition barrier for recording the necessary volumes of data to do high resolution 3D VSP or 3D cross well seismic imaging. Massive 3D VSP{reg_sign} and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that will allow the Gas industry to take the next step in their quest for higher resolution images of the gas reservoirs for the purpose of improving the recovery of the natural gas resources. Today only a fraction of the original Oil or Gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of the detailed compartmentalization of the oil and gas reservoirs. The 400 level 3C borehole seismic receiver array will allow for the economic use of 3D borehole seismic imaging for reservoir characterization and monitoring by allowing the economic recording of the required large data volumes that have a sufficiently dense spatial sampling. By using 3C surface seismic or 3C borehole seismic sources the 400 level receiver arrays will furthermore allow 3D reservoir imaging using 9C data. The 9C borehole seismic data will provide P, SH and SV information for imaging of the complex deep gas reservoirs and allow quantitative prediction of

  14. DEVELOPMENT OF A 400 LEVEL 3C CLAMPED DOWNHOLE SEISMIC RECEIVER ARRAY FOR 3D BOREHOLE SEISMIC IMAGING OF GAS RESERVOIRS

    SciTech Connect

    Bjorn N.P. Paulsson

    2004-06-30

    Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to economically do high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology is currently frustrated by the lack of the acquisition technology necessary to record the large volumes of the high frequency, high signal-to-noise-ratio borehole seismic data needed to do 3D imaging. This project takes direct aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array will remove the technical acquisition barrier for recording the necessary volumes of data to do high resolution 3D VSP or 3D cross well seismic imaging. 3D VSP and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that will allow the Gas industry to take the next step in their quest for higher resolution images of the gas reservoirs for the purpose of improving the recovery of the natural gas resources. Today only a fraction of the original Oil or Gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of the detailed compartmentalization of the oil and gas reservoirs. The 400 level 3C borehole seismic receiver array will allow for the economic use of 3D borehole seismic imaging for reservoir characterization and monitoring by allowing the economic recording of the required large data volumes that have a sufficiently dense spatial sampling. By using 3C surface seismic or 3C borehole seismic sources the 400 level receiver array will furthermore allow 3D reservoir imaging using 9C data. The 9C borehole seismic data will provide P, SH and SV information for imaging of the complex deep gas reservoirs and allow quantitative prediction of the rock and the

  15. DEVELOPMENT OF A 400 LEVEL 3C CLAMPED DOWNHOLE SEISMIC RECEIVER ARRAY FOR 3D BOREHOLE SEISMIC IMAGING OF GAS RESERVOIRS

    SciTech Connect

    Bjorn N.P. Paulsson

    2002-12-01

    Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to economically do high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology is currently frustrated by the lack of the acquisition technology necessary to record the large volumes of the high frequency, high signal-to-noise-ratio borehole seismic data needed to do 3D imaging. This project takes direct aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array will remove the technical acquisition barrier for recording the necessary volumes of data to do high resolution 3D VSP or 3D cross well seismic imaging. 3D VSP and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that will allow the Gas industry to take the next step in their quest for higher resolution images of the gas reservoirs for the purpose of improving the recovery of the natural gas resources. Today only a fraction of the original Oil or Gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of the detailed compartmentalization of the oil and gas reservoirs. The 400 level 3C borehole seismic receiver array will allow for the economic use of 3D borehole seismic imaging for reservoir characterization and monitoring by allowing the economic recording of the required large data volumes that have a sufficiently dense spatial sampling. By using 3C surface seismic or 3C borehole seismic sources the 400 level receiver array will furthermore allow 3D reservoir imaging using 9C data. The 9C borehole seismic data will provide P, SH and SV information for imaging of the complex deep gas reservoirs and allow quantitative prediction of the rock and the

  16. DEVELOPMENT OF A 400 LEVEL 3C CLAMPED DOWNHOLE SEISMIC RECEIVER ARRAY FOR 3D BOREHOLE SEISMIC IMAGING OF GAS RESERVOIRS

    SciTech Connect

    Bjorn N.P. Paulsson

    2004-05-31

    Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to economically do high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology is currently frustrated by the lack of the acquisition technology necessary to record the large volumes of the high frequency, high signal-to-noise-ratio borehole seismic data needed to do 3D imaging. This project takes direct aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array will remove the technical acquisition barrier for recording the necessary volumes of data to do high resolution 3D VSP or 3D cross well seismic imaging. 3D VSP and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that will allow the Gas industry to take the next step in their quest for higher resolution images of the gas reservoirs for the purpose of improving the recovery of the natural gas resources. Today only a fraction of the original Oil or Gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of the detailed compartmentalization of the oil and gas reservoirs. The 400 level 3C borehole seismic receiver array will allow for the economic use of 3D borehole seismic imaging for reservoir characterization and monitoring by allowing the economic recording of the required large data volumes that have a sufficiently dense spatial sampling. By using 3C surface seismic or 3C borehole seismic sources the 400 level receiver array will furthermore allow 3D reservoir imaging using 9C data. The 9C borehole seismic data will provide P, SH and SV information for imaging of the complex deep gas reservoirs and allow quantitative prediction of the rock and the

  17. DEVELOPMENT OF A 400 LEVEL 3C CLAMPED DOWNHOLE SEISMIC RECEIVER ARRAY FOR 3D BOREHOLE SEISMIC IMAGING OF GAS RESERVOIRS

    SciTech Connect

    Bjorn N.P Paulsson

    2003-09-01

    Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to economically do high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology is currently frustrated by the lack of the acquisition technology necessary to record the large volumes of the high frequency, high signal-to-noise-ratio borehole seismic data needed to do 3D imaging. This project takes direct aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array will remove the technical acquisition barrier for recording the necessary volumes of data to do high resolution 3D VSP or 3D cross well seismic imaging. 3D VSP and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that will allow the Gas industry to take the next step in their quest for higher resolution images of the gas reservoirs for the purpose of improving the recovery of the natural gas resources. Today only a fraction of the original Oil or Gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of the detailed compartmentalization of the oil and gas reservoirs. The 400 level 3C borehole seismic receiver array will allow for the economic use of 3D borehole seismic imaging for reservoir characterization and monitoring by allowing the economic recording of the required large data volumes that have a sufficiently dense spatial sampling. By using 3C surface seismic or 3C borehole seismic sources the 400 level receiver array will furthermore allow 3D reservoir imaging using 9C data. The 9C borehole seismic data will provide P, SH and SV information for imaging of the complex deep gas reservoirs and allow quantitative prediction of the rock and the

  18. DEVELOPMENT OF A 400 LEVEL 3C CLAMPED DOWNHOLE SEISMIC RECEIVER ARRAY FOR 3D BOREHOLE SEISMIC IMAGING OF GAS RESERVOIRS.

    SciTech Connect

    Bjorn N.P Paulsson

    2003-01-01

    Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to economically do high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology is currently frustrated by the lack of the acquisition technology necessary to record the large volumes of the high frequency, high signal-to-noise-ratio borehole seismic data needed to do 3D imaging. This project takes direct aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array will remove the technical acquisition barrier for recording the necessary volumes of data to do high resolution 3D VSP or 3D cross well seismic imaging. 3D VSP and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that will allow the Gas industry to take the next step in their quest for higher resolution images of the gas reservoirs for the purpose of improving the recovery of the natural gas resources. Today only a fraction of the original Oil or Gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of the detailed compartmentalization of the oil and gas reservoirs. The 400 level 3C borehole seismic receiver array will allow for the economic use of 3D borehole seismic imaging for reservoir characterization and monitoring by allowing the economic recording of the required large data volumes that have a sufficiently dense spatial sampling. By using 3C surface seismic or 3C borehole seismic sources the 400 level receiver array will furthermore allow 3D reservoir imaging using 9C data. The 9C borehole seismic data will provide P, SH and SV information for imaging of the complex deep gas reservoirs and allow quantitative prediction of the rock and the

  19. DEVELOPMENT OF A 400 LEVEL 3C CLAMPED DOWNHOLE SEISMIC RECEIVER ARRAY FOR 3D BOREHOLE SEISMIC IMAGING OF GAS RESERVOIRS

    SciTech Connect

    Bjorn N.P. Paulsson

    2004-09-30

    Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to economically do high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology is currently frustrated by the lack of the acquisition technology necessary to record the large volumes of the high frequency, high signal-to-noise-ratio borehole seismic data needed to do 3D imaging. This project takes direct aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array will remove the technical acquisition barrier for recording the necessary volumes of data to do high resolution 3D VSP or 3D cross well seismic imaging. Massive 3D VSP{reg_sign} and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that will allow the Gas industry to take the next step in their quest for higher resolution images of the gas reservoirs for the purpose of improving the recovery of the natural gas resources. Today only a fraction of the original Oil or Gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of the detailed compartmentalization of the oil and gas reservoirs. The 400 level 3C borehole seismic receiver array will allow for the economic use of 3D borehole seismic imaging for reservoir characterization and monitoring by allowing the economic recording of the required large data volumes that have a sufficiently dense spatial sampling. By using 3C surface seismic or 3C borehole seismic sources the 400 level receiver arrays will furthermore allow 3D reservoir imaging using 9C data. The 9C borehole seismic data will provide P, SH and SV information for imaging of the complex deep gas reservoirs and allow quantitative prediction of

  20. DEVELOPMENT OF A 400 LEVEL 3C CLAMPED DOWNHOLE SEISMIC RECEIVER ARRAY FOR 3D BOREHOLE SEISMIC IMAGING OF GAS RESERVOIRS

    SciTech Connect

    Bjorn N.P. Paulsson

    2003-12-01

    Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to economically do high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology is currently frustrated by the lack of the acquisition technology necessary to record the large volumes of the high frequency, high signal-to-noise-ratio borehole seismic data needed to do 3D imaging. This project takes direct aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array will remove the technical acquisition barrier for recording the necessary volumes of data to do high resolution 3D VSP or 3D cross well seismic imaging. 3D VSP and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that will allow the Gas industry to take the next step in their quest for higher resolution images of the gas reservoirs for the purpose of improving the recovery of the natural gas resources. Today only a fraction of the original Oil or Gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of the detailed compartmentalization of the oil and gas reservoirs. The 400 level 3C borehole seismic receiver array will allow for the economic use of 3D borehole seismic imaging for reservoir characterization and monitoring by allowing the economic recording of the required large data volumes that have a sufficiently dense spatial sampling. By using 3C surface seismic or 3C borehole seismic sources the 400 level receiver array will furthermore allow 3D reservoir imaging using 9C data. The 9C borehole seismic data will provide P, SH and SV information for imaging of the complex deep gas reservoirs and allow quantitative prediction of the rock and the

  1. DEVELOPMENT OF A 400 LEVEL 3C CLAMPED DOWNHOLE SEISMIC RECEIVER ARRAY FOR 3D BOREHOLE SEISMIC IMAGING OF GAS RESERVOIRS

    SciTech Connect

    Bjorn N.P Paulsson

    2003-07-01

    Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to economically do high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology is currently frustrated by the lack of the acquisition technology necessary to record the large volumes of the high frequency, high signal-to-noise-ratio borehole seismic data needed to do 3D imaging. This project takes direct aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array will remove the technical acquisition barrier for recording the necessary volumes of data to do high resolution 3D VSP or 3D cross well seismic imaging. 3D VSP and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that will allow the Gas industry to take the next step in their quest for higher resolution images of the gas reservoirs for the purpose of improving the recovery of the natural gas resources. Today only a fraction of the original Oil or Gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of the detailed compartmentalization of the oil and gas reservoirs. The 400 level 3C borehole seismic receiver array will allow for the economic use of 3D borehole seismic imaging for reservoir characterization and monitoring by allowing the economic recording of the required large data volumes that have a sufficiently dense spatial sampling. By using 3C surface seismic or 3C borehole seismic sources the 400 level receiver array will furthermore allow 3D reservoir imaging using 9C data. The 9C borehole seismic data will provide P, SH and SV information for imaging of the complex deep gas reservoirs and allow quantitative prediction of the rock and the

  2. DEVELOPMENT OF A 400 LEVEL 3C CLAMPED DOWNHOLE SEISMIC RECEIVER ARRAY FOR 3D BOREHOLE SEISMIC IMAGING OF GAS RESERVOIRS

    SciTech Connect

    Bjorn N.P. Paulsson

    2004-05-01

    Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to economically do high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology is currently frustrated by the lack of the acquisition technology necessary to record the large volumes of the high frequency, high signal-to-noise-ratio borehole seismic data needed to do 3D imaging. This project takes direct aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array will remove the technical acquisition barrier for recording the necessary volumes of data to do high resolution 3D VSP or 3D cross well seismic imaging. 3D VSP and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that will allow the Gas industry to take the next step in their quest for higher resolution images of the gas reservoirs for the purpose of improving the recovery of the natural gas resources. Today only a fraction of the original Oil or Gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of the detailed compartmentalization of the oil and gas reservoirs. The 400 level 3C borehole seismic receiver array will allow for the economic use of 3D borehole seismic imaging for reservoir characterization and monitoring by allowing the economic recording of the required large data volumes that have a sufficiently dense spatial sampling. By using 3C surface seismic or 3C borehole seismic sources the 400 level receiver array will furthermore allow 3D reservoir imaging using 9C data. The 9C borehole seismic data will provide P, SH and SV information for imaging of the complex deep gas reservoirs and allow quantitative prediction of the rock and the

  3. Development of a 400 Level 3C Clamped Downhole Seismic Receiver Array for 3D Borehole Seismic Imaging of Gas Reservoirs

    SciTech Connect

    Bjorn N.P. Paulsson

    2005-08-21

    Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to economically do high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology is currently hampered by the lack of the acquisition technology necessary to record the large volumes of the high frequency, high signal-to-noise-ratio borehole seismic data needed to do 3D imaging. This project takes direct aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array will remove the technical acquisition barrier for recording the necessary volumes of data to do high resolution 3D VSP or 3D cross well seismic imaging. Massive 3D VSP{reg_sign} and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that will allow the Gas industry to take the next step in their quest for higher resolution images of the gas reservoirs for the purpose of improving the recovery of the natural gas resources. Today only a fraction of the original Oil or Gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of the detailed compartmentalization of the oil and gas reservoirs. The 400 level 3C borehole seismic receiver array will allow for the economic use of 3D borehole seismic imaging for reservoir characterization and monitoring by allowing the economic recording of the required large data volumes that have a sufficiently dense spatial sampling. By using 3C surface seismic or 3C borehole seismic sources the 400 level receiver arrays will furthermore allow 3D reservoir imaging using 9C data. The 9C borehole seismic data will provide P, SH and SV information for imaging of the complex deep gas reservoirs and allow quantitative prediction of

  4. Development of a 400 Level 3C Clamped Downhole Seismic Receiver Array for 3D Borehole Seismic Imaging of Gas Reservoirs

    SciTech Connect

    Bjorn N. P. Paulsson

    2005-09-30

    Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to economically do high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology is currently hampered by the lack of the acquisition technology necessary to record the large volumes of the high frequency, high signal-to-noise-ratio borehole seismic data needed to do 3D imaging. This project takes direct aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array will remove the technical acquisition barrier for recording the necessary volumes of data to do high resolution 3D VSP or 3D cross well seismic imaging. Massive 3D VSP{reg_sign} and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that will allow the Gas industry to take the next step in their quest for higher resolution images of the gas reservoirs for the purpose of improving the recovery of the natural gas resources. Today only a fraction of the original Oil or Gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of the detailed compartmentalization of the oil and gas reservoirs. The 400 level 3C borehole seismic receiver array will allow for the economic use of 3D borehole seismic imaging for reservoir characterization and monitoring by allowing the economic recording of the required large data volumes that have a sufficiently dense spatial sampling. By using 3C surface seismic or 3C borehole seismic sources the 400 level receiver arrays will furthermore allow 3D reservoir imaging using 9C data. The 9C borehole seismic data will provide P, SH and SV information for imaging of the complex deep gas reservoirs and allow quantitative prediction of

  5. Development of a 400 Level 3C Clamped Downhole Seismic Receiver Array for 3D Borehole Seismic Imaging of Gas Reservoirs

    SciTech Connect

    Bjorn N.P Paulsson

    2006-05-05

    Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to economically do high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology is currently hampered by the lack of the acquisition technology necessary to record the large volumes of the high frequency, high signal-to-noise-ratio borehole seismic data needed to do 3D imaging. This project takes direct aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array will remove the technical acquisition barrier for recording the necessary volumes of data to do high resolution 3D VSP or 3D cross well seismic imaging. Massive 3D VSP{reg_sign} and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that will allow the Gas industry to take the next step in their quest for higher resolution images of the gas reservoirs for the purpose of improving the recovery of the natural gas resources. Today only a fraction of the original Oil or Gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of the detailed compartmentalization of the oil and gas reservoirs. The 400 level 3C borehole seismic receiver array will allow for the economic use of 3D borehole seismic imaging for reservoir characterization and monitoring by allowing the economic recording of the required large data volumes that have a sufficiently dense spatial sampling. By using 3C surface seismic or 3C borehole seismic sources the 400 level receiver arrays will furthermore allow 3D reservoir imaging using 9C data. The 9C borehole seismic data will provide P, SH and SV information for imaging of the complex deep gas reservoirs and allow quantitative prediction of

  6. 3D imaging of cone photoreceptors over extended time periods using optical coherence tomography with adaptive optics

    NASA Astrophysics Data System (ADS)

    Kocaoglu, Omer P.; Lee, Sangyeol; Jonnal, Ravi S.; Wang, Qiang; Herde, Ashley E.; Besecker, Jason; Gao, Weihua; Miller, Donald T.

    2011-03-01

    Optical coherence tomography with adaptive optics (AO-OCT) is a highly sensitive, noninvasive method for 3D imaging of the microscopic retina. The purpose of this study is to advance AO-OCT technology by enabling repeated imaging of cone photoreceptors over extended periods of time (days). This sort of longitudinal imaging permits monitoring of 3D cone dynamics in both normal and diseased eyes, in particular the physiological processes of disc renewal and phagocytosis, which are disrupted by retinal diseases such as age related macular degeneration and retinitis pigmentosa. For this study, the existing AO-OCT system at Indiana underwent several major hardware and software improvements to optimize system performance for 4D cone imaging. First, ultrahigh speed imaging was realized using a Basler Sprint camera. Second, a light source with adjustable spectrum was realized by integration of an Integral laser (Femto Lasers, λc=800nm, ▵λ=160nm) and spectral filters in the source arm. For cone imaging, we used a bandpass filter with λc=809nm and ▵λ=81nm (2.6 μm nominal axial resolution in tissue, and 167 KHz A-line rate using 1,408 px), which reduced the impact of eye motion compared to previous AO-OCT implementations. Third, eye motion artifacts were further reduced by custom ImageJ plugins that registered (axially and laterally) the volume videos. In two subjects, cone photoreceptors were imaged and tracked over a ten day period and their reflectance and outer segment (OS) lengths measured. High-speed imaging and image registration/dewarping were found to reduce eye motion to a fraction of a cone width (1 μm root mean square). The pattern of reflections in the cones was found to change dramatically and occurred on a spatial scale well below the resolution of clinical instruments. Normalized reflectance of connecting cilia (CC) and OS posterior tip (PT) of an exemplary cone was 54+/-4, 47+/-4, 48+/-6, 50+/-5, 56+/-1% and 46+/-4, 53+/-4, 52+/-6, 50+/-5, 44

  7. Predictions of non-LTE spectra from large scale 3D magneto-hydrodynamic modelling of wire array Z-pinches

    NASA Astrophysics Data System (ADS)

    Niasse, Nicolas; Chittenden, Jeremy

    2012-10-01

    The last few years have seen considerable advances in the application of high performance computing techniques to 3D simulations of wire array Z-pinches. Whilst the intense soft X-ray radiation output is the principle application of wire arrays, the ability to encompass spectrally detailed models of this emission within such 3D calculations was thought to be computationally prohibitive. We have developed a non-LTE atomic and radiation physics model with detailed configuration accounting and n-l splitting which is sufficiently streamlined to run in-line with large scale 3D simulations. In order to handle the volume of data generated by the spectral treatment of the billions of numerical cells, a novel data structure derived from a self-balancing binary search tree was developed, enabling the use of non-LTE DCA calculations within large scale 3D simulations for the first time. A brief description of the model is provided and the application of the simulations to understanding the X-ray generation processes within wire array Z-pinches on the Z generator at Sandia National Laboratory is reported. The contribution of the ion temperature and the motion of the unstable plasma at stagnation to the Doppler widths of the lines is described in detail.

  8. Assessing the quality of earthquake source models using 3-D forward modelling of long-period seismic data

    NASA Astrophysics Data System (ADS)

    Ferreira, A. M.; Vallée, M.; Lentas, K.

    2010-12-01

    Accurate earthquake point source parameters (e.g. seismic moment, depth and focal mechanism) provide key first-order information for detailed studies of the earthquake source process and for improved seismic and tsunami hazard evaluation. In order to objectively assess the quality of seismic source models, it is important to go beyond classical resolution/misfit checks. In particular, it is desirable to apply sophisticated modeling techniques to quantify uncertainties due to simplified theoretical formulations and/or Earth structure employed to build the source models. Moreover, it is important to verify how well the models explain data not used in their construction for a complete, quantitative assessment of the earthquake source models. In this study we compare the quality of the surface-wave Centroid Moment Tensor (CMT) method with that of the SCARDEC method, which is a new automated body-wave technique for the fast simultaneous determination of the seismic moment, focal mechanism, depth and source time functions of large earthquakes. We focus on the major shallow subduction earthquakes of the last 20 years, for which there are some systematic differences between SCARDEC and CMT source parameters, notably in fault dip angle and moment magnitude. Because the SCARDEC method is based on body-wave deconvolution using ray methods in a 1D Earth model, we test how well SCARDEC source parameters explain long-period seismic data (surface waves and normal modes) compared to the CMT method. We calculate theoretical seismograms using two forward modelling techniques (full ray theory and spectral element method) to simulate the long-period seismic wavefield for the 3D Earth model S20RTS combined with the crust model CRUST2.0, and for two point source models: (i) the SCARDEC model; and (ii) the Global CMT model. We compare the synthetic seismograms with real broadband data from the FDSN for the major subduction earthquakes of the last 20 years. We show that SCARDEC source

  9. Upgrading and testing the 3D reconstruction of gamma-ray air showers as observed with an array of Cherenkov telescopes

    SciTech Connect

    Naumann-Godo, Melitta; Degrange, Bernard

    2008-12-24

    Stereoscopic arrays of Imaging Cherenkov Telescopes allow to reconstruct gamma-ray-induced showers in 3 dimensions. An analysis method based on a simple 3D-model of electromagnetic showers and implemented in the framework of the H.E.S.S. experiment was recently improved by an additional quality criterion which reduces the background contamination by a factor of about 2 in the case of extended sources, while hardly affecting gamma-ray selection efficiency. Moreover, the dramatic flares of PKS 2155-304 in July 2006, which provided H.E.S.S. data with an almost pure gamma-ray sample, offered the unique opportunity of a precision test of the 3D-reconstruction method as well as of the H.E.S.S. simulations used in its calibration. An agreement at a few percent level is found between data and simulations for the distributions of all 3D shower parameters.

  10. Development of a 400 Level 3C Clamped Downhole Seismic Receiver Array for 3D Borehole Seismic Imaging of Gas Reservoirs

    SciTech Connect

    Bjorn N. P. Paulsson

    2006-09-30

    Borehole seismology is the highest resolution geophysical imaging technique available today to the oil and gas industry for characterization and monitoring of oil and gas reservoirs. However, the industry's ability to perform high resolution 3D imaging of deep and complex gas reservoirs using borehole seismology has been hampered by the lack of acquisition technology necessary to record large volumes of high frequency, high signal-to-noise-ratio borehole seismic data. This project took aim at this shortcoming by developing a 400 level 3C clamped downhole seismic receiver array, and accompanying software, for borehole seismic 3D imaging. This large borehole seismic array has removed the technical acquisition barrier for recording the data volumes necessary to do high resolution 3D VSP and 3D cross-well seismic imaging. Massive 3D VSP{reg_sign} and long range Cross-Well Seismology (CWS) are two of the borehole seismic techniques that promise to take the gas industry to the next level in their quest for higher resolution images of deep and complex oil and gas reservoirs. Today only a fraction of the oil or gas in place is produced when reservoirs are considered depleted. This is primarily due to our lack of understanding of detailed compartmentalization of oil and gas reservoirs. In this project, we developed a 400 level 3C borehole seismic receiver array that allows for economic use of 3D borehole seismic imaging for reservoir characterization and monitoring. This new array has significantly increased the efficiency of recording large data volumes at sufficiently dense spatial sampling to resolve reservoir complexities. The receiver pods have been fabricated and tested to withstand high temperature (200 C/400 F) and high pressure (25,000 psi), so that they can operate in wells up to 7,620 meters (25,000 feet) deep. The receiver array is deployed on standard production or drill tubing. In combination with 3C surface seismic or 3C borehole seismic sources, the 400

  11. Flux avalanches in superconducting films with periodic arrays of holes.

    SciTech Connect

    Vlasko-Vlasov, V.; Welp, U.; Metlushko, V.; Crabtree, G. W.; Materials Science Division; Inst. of Solid State Physics RAS

    2000-01-01

    The magnetic flux dynamics in Nb films with periodic hole arrays is studied magneto-optically. Flux motion in the shape of microavalanches along {l_brace}100{r_brace} and {l_brace}110{r_brace} directions of the hole lattice is observed. At lower temperatures anisotropic large scale thermo-magnetic avalanches dominate flux entry and exit. At T-T{sub c} critical-state-like field patterns periodically appear at fractions of the matching field.

  12. Conductive polymer-mediated 2D and 3D arrays of Mn3O4 nanoblocks and mesoporous conductive polymers as their replicas

    NASA Astrophysics Data System (ADS)

    Nakagawa, Yoshitaka; Kageyama, Hiroyuki; Matsumoto, Riho; Oaki, Yuya; Imai, Hiroaki

    2015-11-01

    Orientation-controlled 2D and 3D microarrays of Mn3O4 nanocuboids that were mediated by a conductive polymer were fabricated by evaporation-induced self-assembly of the oxide nanoblocks and subsequent polymerization of pyrrole in the interparticle spaces. Free-standing mesoporous polypyrroles (PPy) having chain- and square-grid-like nanovoid arrays were obtained as replicas of the composite assemblies by dissolving the oxide nanoblocks. The PPy-mediated manganese oxide arrays exhibited stable electrochemical performance as an ultrathin anode of a lithium-ion secondary battery.Orientation-controlled 2D and 3D microarrays of Mn3O4 nanocuboids that were mediated by a conductive polymer were fabricated by evaporation-induced self-assembly of the oxide nanoblocks and subsequent polymerization of pyrrole in the interparticle spaces. Free-standing mesoporous polypyrroles (PPy) having chain- and square-grid-like nanovoid arrays were obtained as replicas of the composite assemblies by dissolving the oxide nanoblocks. The PPy-mediated manganese oxide arrays exhibited stable electrochemical performance as an ultrathin anode of a lithium-ion secondary battery. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr05912g

  13. High-Performance Stable Field Emission with Ultralow Turn on Voltage from rGO Conformal Coated TiO2 Nanotubes 3D Arrays.

    PubMed

    Agrawal, Yogyata; Kedawat, Garima; Kumar, Pawan; Dwivedi, Jaya; Singh, V N; Gupta, R K; Gupta, Bipin Kumar

    2015-01-01

    A facile method to produce conformal coated reduced graphene oxide (rGO) on vertically aligned titanium oxide (TiO2) nanotubes three dimensional (3D) arrays (NTAs) is demonstrated for enhanced field emission display applications. These engineered nano arrays exhibit efficient electron field emission properties such as high field emission current density (80 mA/cm(2)), low turn-on field (1.0 V/μm) and field enhancement factor (6000) with high emission current stability. Moreover, these enhancements observed in nano arrays attribute to the contribution of low work function with non-rectifying barriers, which allow an easy injection of electrons from the conduction band of TiO2 into the Fermi level of reduced graphene oxide under external electric field. The obtained results are extremely advantageous for its potential application in field emission devices. PMID:26152895

  14. High-Performance Stable Field Emission with Ultralow Turn on Voltage from rGO Conformal Coated TiO2 Nanotubes 3D Arrays

    PubMed Central

    Agrawal, Yogyata; Kedawat, Garima; Kumar, Pawan; Dwivedi, Jaya; Singh, V. N.; Gupta, R. K.; Gupta, Bipin Kumar

    2015-01-01

    A facile method to produce conformal coated reduced graphene oxide (rGO) on vertically aligned titanium oxide (TiO2) nanotubes three dimensional (3D) arrays (NTAs) is demonstrated for enhanced field emission display applications. These engineered nano arrays exhibit efficient electron field emission properties such as high field emission current density (80 mA/cm2), low turn-on field (1.0 V/μm) and field enhancement factor (6000) with high emission current stability. Moreover, these enhancements observed in nano arrays attribute to the contribution of low work function with non-rectifying barriers, which allow an easy injection of electrons from the conduction band of TiO2 into the Fermi level of reduced graphene oxide under external electric field. The obtained results are extremely advantageous for its potential application in field emission devices. PMID:26152895

  15. Using 1D theory to understand 3D stagnation of a wire-array Z pinch in the absence of radiation

    NASA Astrophysics Data System (ADS)

    Yu, Edmund

    2015-11-01

    Many high-energy-density systems implode towards the axis of symmetry, where it collides on itself, forming a hot plasma. However, experiments show these imploding plasmas develop three-dimensional (3D) structures. As a result, the plasma cannot completely dissipate its kinetic energy at stagnation, instead retaining significant 3D flow. A useful tool for understanding the effects of this residual flow is 3D simulation, but the amount and complexity of information can be daunting. To address this problem, we explore the connection between 3D simulation and one-dimensional (1D) theory. Such a connection, if it exists, is mutually beneficial: 1D theory can provide a clear picture of the underlying dynamics of 3D stagnation. On the other hand, deviations between theory and simulation suggest how 1D theory must be modified to account for 3D effects. In this work, we focus on a 3D, magnetohydrodynamic simulation of a compact wire-array Z pinch. To provide a simpler background against which to test our ideas, we artificially turn off radiation during the stagnation phase. Examination of the initial accumulation of mass on axis reveals oblique collision between jets, shock accretion, and vortex formation. Despite evidence for shock-dominated stagnation, a 1D shockless stagnation solution is more appropriate for describing the global dynamics, in that it reproduces the increase of on-axis density with time. However, the 1D solution must be modified to account for 3D effects: the flows suggest enhanced thermal transport as well as centrifugal force. Upon reaching peak compression, the stagnation transitions to a second phase, in which the high-pressure core on axis expands outward into the remaining imploding plasma. During this phase, a 1D shock solution describes the growth of the shock accretion region, as well as the decrease of on-axis density with time. However, the effect of 3D flows is still present: the on-axis temperature does not cool during expansion, which

  16. Magnetic field induced controllable self-assembly of maghemite nanocrystals: From 3D arrays to 1D nanochains

    NASA Astrophysics Data System (ADS)

    Tang, Yan; Chen, Qianwang; Chen, Rongsheng

    2015-08-01

    A hydrothermal process has been used to synthesize walnut-like maghemite superstructures which can be further self-assembled in a controllable manner into ordered three-dimensional (3D) architectures and one-dimensional (1D) nanochains in the presence of different external magnetic field. The assembly behavior of the maghemite nanoparticles isclosely related to the van der Waals interactions and external-field-induced magnetic dipole interactions. The magnetic properties of these nanostructures are also investigated.

  17. Real-time 3D image reconstruction of a 24×24 row-column addressing array: from raw data to image

    NASA Astrophysics Data System (ADS)

    Li, Chunyu; Yang, Jiali; Li, Xu; Zhong, Xiaoli; Song, Junjie; Ding, Mingyue; Yuchi, Ming

    2016-04-01

    This paper presents a work of real-time 3-D image reconstruction for a 7.5-MHz, 24×24 row-column addressing array transducer. The transducer works with a predesigned transmit/receive module. After the raw data are captured by the NI PXIe data acquisition (DAQ) module, the following processing procedures are performed: delay and sum (DAS), base-line calibration, envelope detection, logarithm compression, down-sampling, gray scale mapping and 3-D display. These procedures are optimized for obtaining real-time 3-D images. Fixed-point focusing scheme is applied in delay and sum (DAS) to obtain line data from channel data. Zero-phase high-pass filter is used to calibrate the base-line shift of echo. The classical Hilbert transformation is adopted to detect the envelopes of echo. Logarithm compression is implemented to enlarge the weak signals and narrow the gap from the strong ones. Down-sampling reduces the amount of data to improve the processing speed. Linear gray scale mapping is introduced that the weakest signal is mapped to 0 and the strongest signal 255. The real-time 3-D images are displayed with multi-planar mode, which shows three orthogonal sections (vertical section, coronal section, transverse section). A trigger signal is sent from the transmit/receive module to the DAQ module at the start of each volume data generation to ensure synchronization between these two modules. All procedures, include data acquisition (DAQ), signal processing and image display, are programmed on the platform of LabVIEW. 675MB raw echo data are acquired in one minute to generate 24×24×48, 27fps 3-D images. The experiment on the strong reflection object (aluminum slice) shows the feasibility of the whole process from raw data to real-time 3-D images.

  18. Design of intelligent mesoscale periodic array structures utilizing smart hydrogel

    NASA Technical Reports Server (NTRS)

    Sunkara, H. B.; Penn, B. G.; Frazier, D. O.; Weissman, J. M.; Asher, S. A.

    1996-01-01

    Mesoscale Periodic Array Structures (MPAS, also known as crystalline colloidal arrays), composed of aqueous or nonaqueous dispersions of self-assembled submicron colloidal spheres are emerging toward the development of advanced optical devices for technological applications. This is because of their unique optical diffraction properties and the ease with which these intriguing properties can be modulated experimentally. Moreover our recent advancements in this area which include 'locking' the liquid MPAS into solid or semisolid polymer matrices for greater stability with longer life span, and incorporation of CdS quantum dots and laser dyes into colloidal spheres to obtain nonlinear optical (NLO) responses further corroborate the use of MPAS in optical technology. Our long term goal is fabrication of all-optical and electro-optical devices such as spatial light modulators for optical signal processing and flat panel display devices by utilizing intelligent nonlinear periodic array structural materials. Here we show further progress in the design of novel linear MPAS which have the ability to sense and respond to an external source such as temperature. This is achieved by combining the self-assembly properties of polymer colloidal spheres and thermoshrinking properties of smart polymer gels. At selected temperatures the periodic array efficiently Bragg diffracts light and transmits most of the light at other temperatures. Hence these intelligent systems are of potential use as fixed notch filters optical switches or limiters to protect delicate optical sensors from high intensity laser radiation.

  19. 3D silver nanoparticles decorated zinc oxide/silicon heterostructured nanomace arrays as high-performance surface-enhanced Raman scattering substrates.

    PubMed

    Huang, Jian; Chen, Feng; Zhang, Qing; Zhan, Yonghua; Ma, Dayan; Xu, Kewei; Zhao, Yongxi

    2015-03-18

    Three-dimensional (3D) hierarchical nanostructures have been considered as one of the most promising surface-enhanced Raman spectroscopy (SERS) substrates because of the ordered arrangement of high-density hotspots along the third dimension direction. Herein, we reported a unique 3D nanostructure for SERS detection based on silver nanoparticles (AgNPs) decorated zinc oxide/silicon (ZnO/Si) heterostructured nanomace arrays. They were prepared by two steps: (1) Si nanoneedles were grafted onto ZnO nanorod arrays via a catalyst-assisted vapor-liquid-solid (VLS) growth mechanism. (2) AgNPs were rapidly immobilized on the surface of nanomaces by a facile galvanic displacement reaction. The fabricated substrates were employed to detect rhodamine 6G (R6G) with a detection limit down to 10(-16) M, and exhibited a high-enhanced performance (enhancement factor (EF) as high as 8.7 × 10(7)). To illustrate the potential value of the prepared substrates, the different concentrations of melamine aqueous solution (from 10(-4) to 10(-10) M) were detected, and a quantitative relationship between the SERS spectrum intensity and the melamine concentration had been established. In addition, the measure of melamine residual in pure milk was carried out successfully, and the results indicated that the prepared 3D nanomace substrates had great potential in food inspection, environment protection, and a few other technologically important fields. PMID:25731067

  20. Dimensionality-dependent charge transport in close-packed nanoparticle arrays: from 2D to 3D

    PubMed Central

    Wang, Ying; Duan, Chao; Peng, Lianmao; Liao, Jianhui

    2014-01-01

    Charge transport properties in close-packed nanoparticle arrays with thickness crossing over from two dimensions to three dimensions have been studied. The dimensionality transition of nanoparticle arrays was realized by continually printing spatially well-defined nanoparticle monolayers on top of the device in situ. The evolution of charge transport properties depending on the dimensionality has been investigated in both the Efros-Shaklovskii variable-range-hopping (ES-VRH) (low temperature) regime and the sequential hopping (SH) (medium temperature) regime. We find that the energy barriers to transport decrease when the thickness of nanoparticle arrays increases from monolayer to multilayers, but start to level off at the thickness of 4–5 monolayers. The energy barriers are characterized by the coefficient βD at ES-VRH regime and the activation energy Ea at SH regime. Moreover, a turning point for the temperature coefficient of conductance was observed in multilayer nanoparticle arrays at high temperature, which is attributed to the increasing mobility with decreasing temperature of hopping transport in three dimensions. PMID:25523836

  1. Dimensionality-dependent charge transport in close-packed nanoparticle arrays: from 2D to 3D.

    PubMed

    Wang, Ying; Duan, Chao; Peng, Lianmao; Liao, Jianhui

    2014-01-01

    Charge transport properties in close-packed nanoparticle arrays with thickness crossing over from two dimensions to three dimensions have been studied. The dimensionality transition of nanoparticle arrays was realized by continually printing spatially well-defined nanoparticle monolayers on top of the device in situ. The evolution of charge transport properties depending on the dimensionality has been investigated in both the Efros-Shaklovskii variable-range-hopping (ES-VRH) (low temperature) regime and the sequential hopping (SH) (medium temperature) regime. We find that the energy barriers to transport decrease when the thickness of nanoparticle arrays increases from monolayer to multilayers, but start to level off at the thickness of 4-5 monolayers. The energy barriers are characterized by the coefficient βD at ES-VRH regime and the activation energy Ea at SH regime. Moreover, a turning point for the temperature coefficient of conductance was observed in multilayer nanoparticle arrays at high temperature, which is attributed to the increasing mobility with decreasing temperature of hopping transport in three dimensions. PMID:25523836

  2. Dimensionality-dependent charge transport in close-packed nanoparticle arrays: from 2D to 3D

    NASA Astrophysics Data System (ADS)

    Wang, Ying; Duan, Chao; Peng, Lianmao; Liao, Jianhui

    2014-12-01

    Charge transport properties in close-packed nanoparticle arrays with thickness crossing over from two dimensions to three dimensions have been studied. The dimensionality transition of nanoparticle arrays was realized by continually printing spatially well-defined nanoparticle monolayers on top of the device in situ. The evolution of charge transport properties depending on the dimensionality has been investigated in both the Efros-Shaklovskii variable-range-hopping (ES-VRH) (low temperature) regime and the sequential hopping (SH) (medium temperature) regime. We find that the energy barriers to transport decrease when the thickness of nanoparticle arrays increases from monolayer to multilayers, but start to level off at the thickness of 4-5 monolayers. The energy barriers are characterized by the coefficient βD at ES-VRH regime and the activation energy Ea at SH regime. Moreover, a turning point for the temperature coefficient of conductance was observed in multilayer nanoparticle arrays at high temperature, which is attributed to the increasing mobility with decreasing temperature of hopping transport in three dimensions.

  3. Ideal and non-ideal MHD regimes of wire array implosion obtained in 3D hybrid simulations and observed during experiments at NTF.

    SciTech Connect

    Sotnikov, Vladimir Isaakovich; Fiala, V.; Oliver, Bryan Velten; Ivanov, Vladimir V.; LePell, Paul David; Fedin, Dmitry; Mehlhorn, Thomas Alan; Kantsyrev, Victor Leonidovich; Coverdale, Christine Anne; Travnicek, P.; Hellinger, P.; Deeney, Christopher; Jones, Brent Manley; Safronova, Alla S.; Leboeuf, J. N.; Cowan, Thomas E.

    2004-11-01

    Recent 3D hybrid simulation of a plasma current-carrying column revealed two regimes of sausage and kink instability development. In the first regime, with small Hall parameter, development of instabilities leads to appearance of large-scale axial perturbations and eventually to the bending of the plasma column. In the second regime, with five times larger Hall parameter, small-scale perturbations dominated and no bending of the plasma column was observed. Simulation results are compared to recent experimental data, including laser probing, x-ray spectroscopy and time-gated x-ray imaging during wire array implosions at NTF.

  4. Microwave properties of ferromagnetic nanowire arrays patterned with periodic and quasi-periodic structures

    NASA Astrophysics Data System (ADS)

    Lei, Yuxiong; Chen, Zheng; Li, Liangliang

    2015-05-01

    Microwave properties of ferromagnetic nanowire arrays patterned with periodic and quasi-periodic structures were investigated in this study. The periodic and quasi-periodic structures were designed based on Fibonacci sequence and golden ratio. Ni nanowires arrays were electrodeposited in anodic aluminum oxide (AAO) templates with patterned Cu electrodes, and then the AAO templates were attached to the coplanar waveguide lines fabricated on quartz substrate for measurement. The S21 of both periodic and quasi-periodic structure-patterned Ni nanowire arrays showed an extra absorption peak besides the absorption peak due to the ferromagnetic resonance of Ni nanowires. The frequency of the absorption peak caused by the patterned structure could be higher than 40 GHz when the length and arrangement of the structural units were modified. In addition, the frequency of the absorption peak due to the quasi-periodic structure was calculated based on a simple analytical model, and the calculated value was consistent with the measured one. The experimental data showed that it could be a feasible approach to tune the performance of microwave devices by patterning ferromagnetic nanowires.

  5. Patterned Periodic Nanofilter Array for Continuous-Flow Bimolecular Separation

    NASA Astrophysics Data System (ADS)

    Fu, Jianping; Han, Jongyoon

    2006-03-01

    We present an experimental study on sieving process of small biomolecules (i.e., proteins and small DNAs) in one- and two-dimensional periodic arrays of nanofilter. The nanofilters served as artificial sieves with precise pore size characterization and showed exceptional size selectivity and separation efficiency from the periodicity of the environment. A kinetic model is developed to explain the electrophoretic drift of charged molecules across periodically modulated free energy landscapes. Further experimental evidence shows the crossover from Ogston-like sieving to entropic trapping mechanism depending on nanofilter thickness and on electric field strength. We also demonstrate continuous-flow biomolecule separation with a device containing of two-dimensional periodic nanofilter arrays. The interaction between migrating molecules and the two-dimensional physical landscapes cause molecules of different sizes to follow radically different paths leading to separation. Continuous-flow fractionations of small DNA molecules (50bp-766bp) as well as SDS-protein complexes (11kDa-200kDa) were achieved in about 5 minutes with a resolution of 10%. By virtue of its gel-free and continuous-flow operation, this device suggests himself a key component to an integrated biomolecule sample preparation and analysis microsystem.

  6. 3-D flexible nano-textured high-density microelectrode arrays for high-performance neuro-monitoring and neuro-stimulation.

    PubMed

    Gabran, S R I; Salam, Muhammad Tariqus; Dian, Joshua; El-Hayek, Youssef; Perez Velazquez, J L; Genov, Roman; Carlen, Peter L; Salama, M M A; Mansour, Raafat R

    2014-09-01

    We introduce a new 3-D flexible microelectrode array for high performance electrographic neural signal recording and stimulation. The microelectrode architecture maximizes the number of channels on each shank and minimizes its footprint. The electrode was implemented on flexible polyimide substrate using microfabrication and thin-film processing. The electrode has a planar layout and comprises multiple shanks. Each shank is three mm in length and carries six gold pads representing the neuro-interfacing channels. The channels are used in recording important precursors with potential clinical relevance and consequent electrical stimulation to perturb the clinical condition. The polyimide structure satisfied the mechanical characteristics required for the proper electrode implantation and operation. Pad postprocessing technique was developed to improve the electrode electrical performance. The planar electrodes were used for creating 3-D "Waterloo Array" microelectrode with controlled gaps using custom designed stackers. Electrode characterization and benchmarking against commercial equivalents demonstrated the superiority of the Flex electrodes. The Flex and commercial electrodes were associated with low-power implantable responsive neuro-stimulation system. The electrodes performance in recording and stimulation application was quantified through in vitro and in vivo acute and chronic experiments on human brain slices and freely-moving rodents. The Flex electrodes exhibited remarkable drop in the electric impedance (100 times at 100 Hz), improved electrode-electrolyte interface noise (dropped by four times) and higher signal-to-noise ratio (3.3 times). PMID:24876130

  7. Investigation and optimization of a finite element simulation of transducer array systems for 3D ultrasound computer tomography with respect to electrical impedance characteristics

    NASA Astrophysics Data System (ADS)

    Kohout, B.; Pirinen, J.; Ruiter, N. V.

    2012-03-01

    The established standard screening method to detect breast cancer is X-ray mammography. However X-ray mammography often has low contrast for tumors located within glandular tissue. A new approach is 3D Ultrasound Computer Tomography (USCT), which is expected to detect small tumors at an early stage. This paper describes the development, improvement and the results of Finite Element Method (FEM) simulations of the Transducer Array System (TAS) used in our 3D USCT. The focus of this work is on researching the influence of meshing and material parameters on the electrical impedance curves. Thereafter, these findings are used to optimize the simulation model. The quality of the simulation was evaluated by comparing simulated impedance characteristics with measured data of the real TAS. The resulting FEM simulation model is a powerful tool to analyze and optimize transducer array systems applied for USCT. With this simulation model, the behavior of TAS for different geometry modifications was researched. It provides a means to understand the acoustical performances inside of any ultrasound transducer represented by its electrical impedance characteristic.

  8. Combining 3-D plasmonic gold nanorod arrays with colloidal nanoparticles as a versatile concept for reliable, sensitive, and selective molecular detection by SERS.

    PubMed

    Yilmaz, Mehmet; Senlik, Erhan; Biskin, Erhan; Yavuz, Mustafa Selman; Tamer, Ugur; Demirel, Gokhan

    2014-03-28

    The detection of molecules at an ultralow level by Surface-Enhanced Raman Spectroscopy (SERS) has recently attracted enormous interest for various applications especially in biological, medical, and environmental fields. Despite the significant progress, SERS systems are still facing challenges for practical applications related to their sensitivity, reliability, and selectivity. To overcome these limitations, in this study, we have proposed a simple yet facile concept by combining 3-D anisotropic gold nanorod arrays with colloidal gold nanoparticles having different shapes for highly reliable, selective, and sensitive detection of some hazardous chemical and biological warfare agents in trace amounts through SERS. The gold nanorod arrays were created on the BK7 glass slides or silicon wafer surfaces via the oblique angle deposition (OAD) technique without using any template material or lithography technique and their surface densities were adjusted by manipulating the deposition angle (α). It is found that gold nanorod arrays fabricated at α = 10° exhibited the highest SERS enhancement in the absence of colloidal gold nanoparticles. Synergetic enhancement was obviously observed in SERS signals when combining gold nanorod arrays with colloidal gold nanoparticles having different shapes (i.e., spherical, rod, and cage). Due to their ability to produce localized surface plasmons (LSPs) in transverse and longitudinal directions, utilization of colloidal gold nanorods as a synergetic agent led to an increase in the enhancement factor by about tenfold compared to plain gold nanorod arrays. Moreover, we have tested our approach to detect some chemical and biological toxins namely dipicolinic acid (DIP), methyl parathion (MP), and diethyl phosphoramidate (DP). For all toxins, Raman spectra with high signal-to-noise ratios and reproducibility were successfully obtained over a broad concentration range (5 ppm-10 ppb). Our results suggest that the slightly tangled and

  9. 3D Reconstruction of VZV Infected Cell Nuclei and PML Nuclear Cages by Serial Section Array Scanning Electron Microscopy and Electron Tomography

    PubMed Central

    Reichelt, Mike; Joubert, Lydia; Perrino, John; Koh, Ai Leen; Phanwar, Ibanri; Arvin, Ann M.

    2012-01-01

    Varicella-zoster virus (VZV) is a human alphaherpesvirus that causes varicella (chickenpox) and herpes zoster (shingles). Like all herpesviruses, the VZV DNA genome is replicated in the nucleus and packaged into nucleocapsids that must egress across the nuclear membrane for incorporation into virus particles in the cytoplasm. Our recent work showed that VZV nucleocapsids are sequestered in nuclear cages formed from promyelocytic leukemia protein (PML) in vitro and in human dorsal root ganglia and skin xenografts in vivo. We sought a method to determine the three-dimensional (3D) distribution of nucleocapsids in the nuclei of herpesvirus-infected cells as well as the 3D shape, volume and ultrastructure of these unique PML subnuclear domains. Here we report the development of a novel 3D imaging and reconstruction strategy that we term Serial Section Array-Scanning Electron Microscopy (SSA-SEM) and its application to the analysis of VZV-infected cells and these nuclear PML cages. We show that SSA-SEM permits large volume imaging and 3D reconstruction at a resolution sufficient to localize, count and distinguish different types of VZV nucleocapsids and to visualize complete PML cages. This method allowed a quantitative determination of how many nucleocapsids can be sequestered within individual PML cages (sequestration capacity), what proportion of nucleocapsids are entrapped in single nuclei (sequestration efficiency) and revealed the ultrastructural detail of the PML cages. More than 98% of all nucleocapsids in reconstructed nuclear volumes were contained in PML cages and single PML cages sequestered up to 2,780 nucleocapsids, which were shown by electron tomography to be embedded and cross-linked by an filamentous electron-dense meshwork within these unique subnuclear domains. This SSA-SEM analysis extends our recent characterization of PML cages and provides a proof of concept for this new strategy to investigate events during virion assembly at the single cell

  10. L-connect routing of die surface pads to the die edge for stacking in a 3D array

    DOEpatents

    Petersen, Robert W.

    2000-01-01

    Integrated circuit chips and method of routing the interface pads from the face of the chip or die to one or more sidewall surfaces of the die. The interconnection is routed from the face of the die to one or more edges of the die, then routed over the edge of the die and onto the side surface. A new pad is then formed on the sidewall surface, which allows multiple die or chips to be stacked in a three-dimensional array, while enabling follow-on signal routing from the sidewall pads. The routing of the interconnects and formation of the sidewall pads can be carried out in an L-connect or L-shaped routing configuration, using a metalization process such as laser pantography.

  11. Nanoelectronic three-dimensional (3D) nanotip sensing array for real-time, sensitive, label-free sequence specific detection of nucleic acids.

    PubMed

    Esfandyarpour, Rahim; Yang, Lu; Koochak, Zahra; Harris, James S; Davis, Ronald W

    2016-02-01

    The improvements in our ability to sequence and genotype DNA have opened up numerous avenues in the understanding of human biology and medicine with various applications, especially in medical diagnostics. But the realization of a label free, real time, high-throughput and low cost biosensing platforms to detect molecular interactions with a high level of sensitivity has been yet stunted due to two factors: one, slow binding kinetics caused by the lack of probe molecules on the sensors and two, limited mass transport due to the planar structure (two-dimensional) of the current biosensors. Here we present a novel three-dimensional (3D), highly sensitive, real-time, inexpensive and label-free nanotip array as a rapid and direct platform to sequence-specific DNA screening. Our nanotip sensors are designed to have a nano sized thin film as their sensing area (~ 20 nm), sandwiched between two sensing electrodes. The tip is then conjugated to a DNA oligonucleotide complementary to the sequence of interest, which is electrochemically detected in real-time via impedance changes upon the formation of a double-stranded helix at the sensor interface. This 3D configuration is specifically designed to improve the biomolecular hit rate and the detection speed. We demonstrate that our nanotip array effectively detects oligonucleotides in a sequence-specific and highly sensitive manner, yielding concentration-dependent impedance change measurements with a target concentration as low as 10 pM and discrimination against even a single mismatch. Notably, our nanotip sensors achieve this accurate, sensitive detection without relying on signal indicators or enhancing molecules like fluorophores. It can also easily be scaled for highly multiplxed detection with up to 5000 sensors/square centimeter, and integrated into microfluidic devices. The versatile, rapid, and sensitive performance of the nanotip array makes it an excellent candidate for point-of-care diagnostics, and high

  12. Nanoelectronic three-dimensional (3D) nanotip sensing array for real-time, sensitive, label-free sequence specific detection of nucleic acids

    PubMed Central

    Yang, Lu; koochak, Zahra; Harris, James S.; Davis, Ronald W.

    2016-01-01

    The improvements in our ability to sequence and genotype DNA have opened up numerous avenues in the understanding of human biology and medicine with various applications, especially in medical diagnostics. But the realization of a label free, real time, high-throughput and low cost biosensing platforms to detect molecular interactions with a high level of sensitivity has been yet stunted due to two factors: one, slow binding kinetics caused by the lack of probe molecules on the sensors and two, limited mass transport due to the planar structure (two-dimensional) of the current biosensors. Here we present a novel three-dimensional (3D), highly sensitive, real-time, inexpensive and label-free nanotip array as a rapid and direct platform to sequence-specific DNA screening. Our nanotip sensors are designed to have a nano sized thin film as their sensing area (~ 20 nm), sandwiched between two sensing electrodes. The tip is then conjugated to a DNA oligonucleotide complementary to the sequence of interest, which is electrochemically detected in real-time via impedance changes upon the formation of a double-stranded helix at the sensor interface. This 3D configuration is specifically designed to improve the biomolecular hit rate and the detection speed. We demonstrate that our nanotip array effectively detects oligonucleotides in a sequence-specific and highly sensitive manner, yielding concentration-dependent impedance change measurements with a target concentration as low as 10 pM and discrimination against even a single mismatch. Notably, our nanotip sensors achieve this accurate, sensitive detection without relying on signal indicators or enhancing molecules like fluorophores. It can also easily be scaled for highly multiplxed detection with up to 5000 sensors/square centimeter, and integrated into microfluidic devices. The versatile, rapid, and sensitive performance of the nanotip array makes it an excellent candidate for point-of-care diagnostics, and high

  13. 3D shallow structures in the Baogutu area, Karamay, determined by eikonal tomography of short-period ambient noise surface waves

    NASA Astrophysics Data System (ADS)

    Xu, Hongrui; Luo, Yinhe; Chen, Chao; Xu, Yixian

    2016-06-01

    Eikonal tomography based on ambient noise data is one of the most effective methods to reveal shallow earth structures. By tracking surface wave phase fronts, constructing travel time surfaces, and computing the gradients of travel time surfaces to generate phase velocity maps, eikonal tomography avoids the ray tracing and matrix construction and inversion in the traditional surface wave tomography methods. In this study, we collect continuous ambient noise data recorded by a dense seismic array in Karamay, Xinjiang to construct a 3D model of shallow structures using eikonal tomography. The seismic array consists of 35 stations with shortest interstation distance close to 1 km. 890 empirical surface wave Green's functions (EGFs) between each station pair are retrieved by cross-correlating one or two months of continuous ambient noise data. From these EGFs, surface wave travel times in the frequency range of 1.8 to 4.0 Hz are measured by a frequency-time analysis technique (FTAN). Then, eikonal tomography is adopted to construct Rayleigh wave phase velocity maps and estimate the phase velocity uncertainties. Finally, we invert the obtained phase velocity dispersion curves for 1D shear velocity profiles and then assemble these 1D profiles to construct a 3D shear velocity model. Major velocity features of our 3D model are correlated well with the known geological features. A shallow east-west velocity discontinuity is observed, which clearly reflects the lithological change between Baogutu formation (C1b) and Xibeikulasi formation (C1x) of lower Carboniferous system. Low shear velocities are observed beneath the location of porphyry copper deposit (V), possibly related to stockwork fracture and hydrothermal brecciation developed during the intrusion of deep magma in forming the deposit.

  14. 3-D matrix template-assisted growth of oriented oxide nanowire arrays using glancing angle pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Wright, N.; Mateo-Feliciano, D.; Ostoski, A.; Mukherjee, P.; Witanachchi, S.

    Nanosphere lithography is a combination of different methods to nanofabrication. In this work nanosphere lithography is used to study the growth of Zinc Oxide Nano-columns (ZnO NCs) on different diameter Silica Nanosphere (SNS) self-assembled templates. ZnO NCs are promising building blocks for many existing and emerging optical, electrical, and piezoelectric devices, specifically, the seeded growth of other oxide materials. Recently, reports have shown a ferroelectric phase of zinc stannate (ZnSnO3) and while lead zirconium titanate oxide (PZT) has been the main material of interest in ferroelectric and piezoelectric applications, the toxicity of lead has been of great concern. The possibility of developing lead free piezoelectric materials is of great interest in the ferroelectric community. Langmuir-Blodgett method was used to construct a self-assembled monolayer of SNSs on silicon substrates. Oriented ZnO NCs were grown on top of the spheres using the glancing angle pulsed laser deposition technique. Columns were formed in a spatially ordered closed-packed hexagonal configuration. Growth of ZnO NCs was studied as function of ambient Oxygen pressure with SNS size ranging from 250-1000 nm. Cross-sectional Scanning Electron Microscopy and X-ray diffraction (XRD) were used to study the template structure. Relative aspect ratios were studied and showed tunability of column dimensions with sphere size. XRD revealed ZnO NC arrays were c-axis oriented with hexagonal wurtzite structure.

  15. Using Fractional Clock-Period Delays in Telemetry Arraying

    NASA Technical Reports Server (NTRS)

    Fort, David; Rogstad, David; Rogstad, Stephen P.

    2003-01-01

    A set of special digital all-pass finite-impulse- response (FIR) filters produces phase shifts equivalent to delays that equal fractions of the sampling or clock period of a telemetry-data-processing system. These filters have been used to enhance the arraying of telemetry signals that have been received at multiple ground stations from spacecraft (see figure). Somewhat more specifically, these filters have been used to align, in the time domain, the telemetry-data sequences received by the various antennas, in order to maximize the signal-to-noise ratio of the composite telemetric signal obtained by summing the signals received by the antennas. The term arraying in this context denotes a method of enhanced reception of telemetry signals in which several antennas are used to track a single spacecraft. Each antenna receives a signal that comprises a sum of telemetry data plus noise, and these sum data are sent to an arraying combiner for processing. Correlation is the means used to align the set of data from one antenna with that from another antenna. After the data from all the antennas have been aligned in the time domain, they are all added together, sample by sample.

  16. Hierarchical NiMoO4 nanowire arrays supported on macroporous graphene foam as binder-free 3D anodes for high-performance lithium storage.

    PubMed

    Wang, Bo; Li, Songmei; Wu, Xiaoyu; Liu, Jianhua; Tian, Wenming

    2016-01-14

    Novel three-dimensional (3D) NiMoO4 nanowire arrays (NWAs) grown directly onto the surface of macroporous graphene foams (GF) with robust adhesion were synthesized via a facile chemical vapor deposition (CVD) and subsequent hydrothermal route. The as-prepared NiMoO4 nanowires are composed of ultra-small nanoparticles (∼5 nm) with a diameter of 70-150 nm and are several micrometers in length. Such as-grown NiMoO4 NWA/3DGF composites are then evaluated as monolithic electrodes for lithium-ion batteries (LIBs) without the need of binders or metal-based current collectors. Benefitting from the unique three-dimensional arrayed architecture and characteristics with a high specific surface area and more active sites which facilitate fast electron and ionic transport within the electrode, the NiMoO4 NWA/GF composites deliver a high reversible specific capacity of 1088.02 mA h g(-1) at a current density of 200 mA g(-1) and 867.86 mA h g(-1) after 150 cycles (79.77% retention of the second cycle), and excellent rate capability. With the advantages of excellent electrochemical performance and a facile synthesis method, the NiMoO4 nanowire arrays supported on 3DGF exhibit great potential as anode materials for LIBs. PMID:26648554

  17. Periodic magnetic domains in single-crystalline cobalt filament arrays

    NASA Astrophysics Data System (ADS)

    Chen, Fei; Wang, Fan; Jia, Fei; Li, Jingning; Liu, Kai; Huang, Sunxiang; Luan, Zhongzhi; Wu, Di; Chen, Yanbin; Zhu, Jianmin; Peng, Ru-Wen; Wang, Mu

    2016-02-01

    Magnetic structures with controlled domain wall pattern may be applied as potential building blocks for three-dimensional magnetic memory and logic devices. Using a unique electrochemical self-assembly method, we achieve regular single-crystalline cobalt filament arrays with specific geometric profile and crystallographic orientation, and the magnetic domain configuration can be conveniently tailored. We report the transition of periodic antiparallel magnetic domains to compressed vortex magnetic domains depending on the ratio of height to width of the wires. A "phase diagram" is obtained to describe the dependence of the type of magnetic domain and the geometrical profiles of the wires. Magnetoresistance of the filaments demonstrates that the contribution of a series of 180∘ domain walls is over 0.15 % of the zero-field resistance ρ (H =0 ) . These self-assembled magnetic nanofilaments, with controlled periodic domain patterns, offer an interesting platform to explore domain-wall-based memory and logic devices.

  18. Quasi-periodic quantum dot arrays produced by electrochemical synthesis

    SciTech Connect

    Bandyopadhyay, S.; Miller, A.E.; Yue, D.F.; Banerjee, G.; Ricker, R.E.; Jones, S.; Eastman, J.A.; Baugher, E.; Chandrasekhar, M.

    1994-06-01

    We discuss a ``gentle`` electrochemical technique for fabricating quasi-periodic quantum dot arrays. The technique exploits a self-organizing phenomenon to produce quasi-periodic arrangement of dots and provides excellent control over dot size and interdot spacing. Unlike conventional nanolithography, it does not cause radiation damage to the structures during exposure to pattern delineating beams (e-beam, ion-beam or x-ray). Moreover, it does not require harsh processing steps like reactive ion etching, offers a minimum feature size of {approximately}40 {angstrom}, allows the fabrication of structures on nonplanar surfaces (e.g. spherical or cylindrical substrates), is amenable to mass production (millions of wafers can be processed simultaneously) and is potentially orders of magnitude cheaper than conventional nanofabrication. In this paper, we describe our initial results and show the promise of this technique for low-cost and high-yield nanosynthesis.

  19. Modelling and 3D optimisation of CdTe pixels detector array geometry - Extension to small pixels

    NASA Astrophysics Data System (ADS)

    Zumbiehl, A.; Hage-Ali, M.; Fougeres, P.; Koebel, J. M.; Regal, R.; Rit, C.; Ayoub, M.; Siffert, P.

    2001-08-01

    CdTe and CdZnTe pixel detectors offer great interest for many applications, especially for medical and industrial imaging. Up to now, the material, generally, used and investigated for pixel arrays was CZT (Hamel et al., IEEE Trans. Nucl. Sci. 43 (3) (1996) 1422; Barrett et al., Phys. Rev. Lett. 75 (1) (1995) 156; Bennett et al., Nucl. Instr. and Meth. A 392 (1997) 260; Eskin et al., J. Appl. Phys. 85 (2) (1999) 647; Brunett et al., J. Appl. Phys. 86 (7) (1999) 3926; Luke, Nucl. Instr. and Meth. A 380 (1996) 232), but cadmium telluride can also be an appropriate choice, as shown here. However, we clearly demonstrate here that the optimal pixel configuration is highly dependent on the electrical transport properties of the material. Depending on the field of primary interest, either energy resolution or counting rate efficiency in the photopeak, the geometry for each case has to be optimised. For that purpose, we have developed a calculation of the signal induced onto the pixel. Two distinct parts are used: after showing our approach for the weighting potential calculation, we present our results performed by a "pseudo-Monte Carlo" simulation. Results are supported by a few experimental comparisons. We argue about the optimum sizes with clarifying the problems caused by too small and too large pixel sizes. The study field is chosen to be vast, i.e. pixel size to detector thickness ratios ( W/ L) of 1/8-1, and detector thickness of 1.0-8.0 mm. In addition, several electrical transport properties are used. Since efficiency is often of primary interest, thick detectors could be very attractive, which are shown to be really feasible even on CdTe.

  20. The Sitnikov family and the associated families of 3D periodic orbits in the photogravitational RTBP with oblateness

    NASA Astrophysics Data System (ADS)

    Kalantonis, V. S.; Perdios, E. A.; Perdiou, A. E.

    2008-06-01

    We consider the photogravitational restricted three-body problem with oblateness and study the Sitnikov motions. The family of straight line oscillations exists only in the case where the primaries are of equal masses as in the classical Sitnikov problem and have the same oblateness coefficients and radiation factors. A perturbation method based on Floquet theory is applied in order to study the stability of the motion and critical orbits are determined numerically at which families of three-dimensional periodic orbits of the same or double period bifurcate. Many of these families are computed.

  1. Some solutions of the 3D Laplace equation in a layer with oscillating boundary describing an array of nanotubes and an application to cold field emission. I. Regular array

    NASA Astrophysics Data System (ADS)

    Brüning, J.; Dobrokhotov, S. Yu.; Minenkov, D. S.

    2011-12-01

    The aim of this paper is to construct solutions of the Dirichlet problem for the 3D Laplace equation in a layer with highly oscillating boundary. The boundary simulates the surface of a nanotube array, and the solutions are applied to compute the cold field electron emission. We suggest a family of exact solutions that solve the problem for a boundary with appropriate geometry. These solutions, along with the Fowler-Nordheim formula, allow one to present explicit asymptotic formulas for the electric field and the emission current. In this part of the paper, we consider the main mathematical aspects, restricting ourselves to the analysis of properties of the potential created by a single tube and a regular array of tubes. In the next part, we shall consider some cases corresponding to nonregular arrays of tubes and concrete physical examples.

  2. Arrays of 3D double-network hydrogels for the high-throughput discovery of materials with enhanced physical and biological properties.

    PubMed

    Duffy, Cairnan; Venturato, Andrea; Callanan, Anthony; Lilienkampf, Annamaria; Bradley, Mark

    2016-04-01

    Synthetic hydrogels are attractive biomaterials due to their similarity to natural tissues and their chemical tunability, which can impart abilities to respond to environmental cues, e.g. temperature, pH and light. The mechanical properties of hydrogels can be enhanced by the generation of a double-network. Here, we report the development of an array platform that allows the macroscopic synthesis of up to 80 single- and double-network hydrogels on a single microscope slide. This new platform allows for the screening of hydrogels as 3D features in a high-throughput format with the added dimension of significant control over the compressive and tensile properties of the materials, thus widening their potential application. The platform is adaptable to allow different hydrogels to be generated, with the potential ability to tune and alter the first and second network, and represents an exciting tool in material and biomaterial discovery. PMID:26712601

  3. Results From a Borehole Seismometer Array II: 3-D Mapping of an Active Geothermal Field at the Kilauea Lower Rift Zone

    NASA Astrophysics Data System (ADS)

    Shalev, E.; Kenedi, C. L.; Malin, P.

    2008-12-01

    The geothermal power plant in Puna, in southeastern Hawaii, is located in a section of the Kilauea Lower East Rift Zone that was resurfaced by lava flows as recently as 1955, 1960, and 1972. In 2006 a seismic array consisting of eight 3-component stations was installed around the geothermal field in Puna. The instrument depths range from 24 to 210 m. The shallower instruments have 2 Hz geophones and the deeper have 4.5 Hz geophones. 3-D tomographic analyses of P-wave velocity, S-wave velocity, and the Vp/Vs ratio show an area of very fast P-wave velocity at the relatively shallow depth of 2.5 km in the southern section of the field. The same area shows moderate S-wave velocity. This high P-wave velocity anomaly at the southern part of the geothermal field may indicate the presence of dense rock material usually found at greater depths.

  4. 3D pseudospectral time domain for modeling second-harmonic generation in periodically poled lithium niobate ridge-type waveguides

    NASA Astrophysics Data System (ADS)

    Devaux, Fabrice; Lantz, Eric; Chauvet, Mathieu

    2016-04-01

    We report an application of the tri-dimensional pseudo-spectral time domain algorithm, that solves with accuracy the nonlinear Maxwell's equations, to predict second harmonic generation in lithium niobate ridge-type waveguides with high index contrast. Characteristics of the nonlinear process such as conversion efficiency as well as impact of the multimode character of the waveguide are investigated as a function of the waveguide geometry in uniformly and periodically poled medium.

  5. A 60-GHz-band 2 x 4 planar dipole array antenna module fabricated by 3-D SiP technology

    NASA Astrophysics Data System (ADS)

    Suematsu, Noriharu; Suzuki, Yuya; Yoshida, Satoshi; Tanifuji, Shoichi; Kameda, Suguru; Takagi, Tadashi; Tsubouchi, Kazuo

    2014-08-01

    A 2 × 4 phased array antenna module has been developed for 60-GHz-band short- range high-speed wireless communication terminals. To realize the required vertical distance between the antenna elements, the module is made of five sheets of multi-layered organic substrates vertically stacked with Cu balls, and the 1 x 4 dipole array antenna is placed on both the top and bottom organic substrates. To reduce the mutual coupling between the element antennas, a monolithic microwave integrated circuit (MMIC) is flip-chip mounted on the feed line of each element antenna. The Au-stud bump flip-chip mounting technique helps achieve a lower return loss in the transition section at the MMIC than the Au-wire bonded. The placement accuracy of each antenna element in the vertical direction, 60-GHz signal vertical interconnection between the substrates with Cu balls, and flip-chip mounting of the MMIC are confirmed by 3-D computed tomography (CT) scans.

  6. Reproducible Construction of Surface Tension-Mediated Honeycomb Concave Microwell Arrays for Engineering of 3D Microtissues with Minimal Cell Loss.

    PubMed

    Lee, GeonHui; Lee, JaeSeo; Oh, HyunJik; Lee, SangHoon

    2016-01-01

    The creation of engineered 3D microtissues has attracted prodigious interest because of the fact that this microtissue structure is able to mimic in vivo environments. Such microtissues can be applied extensively in the fields of regenerative medicine and tissue engineering, as well as in drug and toxicity screening. Here, we develop a novel method of fabricating a large number of dense honeycomb concave microwells via surface tension-mediated self-construction. More specifically, in order to control the curvature and shape of the concavity in a precise and reproducible manner, a custom-made jig system was designed and fabricated. By applying a pre-set force using the jig system, the shape of the honeycomb concave well was precisely and uniformly controlled, despite the fact that wells were densely packed. The thin wall between the honeycomb wells enables the minimization of cell loss during the cell-seeding process. To evaluate the performance of the honeycomb microwell array, rat hepatocytes were seeded, and spheroids were successfully formed with uniform shape and size. Liver-specific functions such as albumin secretion and cytochrome P450 were subsequently analyzed. The proposed method of fabricating honeycomb concave wells is cost-effective, simple, and reproducible. The honeycomb well array can produce multiple spheroids with minimal cell loss, and can lead to significant contributions in tissue engineering and organ regeneration. PMID:27513567

  7. Reproducible Construction of Surface Tension-Mediated Honeycomb Concave Microwell Arrays for Engineering of 3D Microtissues with Minimal Cell Loss

    PubMed Central

    Lee, GeonHui; Lee, JaeSeo; Oh, HyunJik; Lee, SangHoon

    2016-01-01

    The creation of engineered 3D microtissues has attracted prodigious interest because of the fact that this microtissue structure is able to mimic in vivo environments. Such microtissues can be applied extensively in the fields of regenerative medicine and tissue engineering, as well as in drug and toxicity screening. Here, we develop a novel method of fabricating a large number of dense honeycomb concave microwells via surface tension-mediated self-construction. More specifically, in order to control the curvature and shape of the concavity in a precise and reproducible manner, a custom-made jig system was designed and fabricated. By applying a pre-set force using the jig system, the shape of the honeycomb concave well was precisely and uniformly controlled, despite the fact that wells were densely packed. The thin wall between the honeycomb wells enables the minimization of cell loss during the cell-seeding process. To evaluate the performance of the honeycomb microwell array, rat hepatocytes were seeded, and spheroids were successfully formed with uniform shape and size. Liver-specific functions such as albumin secretion and cytochrome P450 were subsequently analyzed. The proposed method of fabricating honeycomb concave wells is cost-effective, simple, and reproducible. The honeycomb well array can produce multiple spheroids with minimal cell loss, and can lead to significant contributions in tissue engineering and organ regeneration. PMID:27513567

  8. Electrochemical synthesis of quasi-periodic quantum dot arrays

    SciTech Connect

    Miller, A.E.; Yue, D.F.; Banerjee, G.; Bandyopadhyay, S.; Ricker, R.E.; Jones, S.; Eastman, J.A.

    1994-06-01

    The conventional route to nanosynthesis involves beam nanolithography (electron beam, ion beam or-x-ray lithography). Exposure to these beams during pattern delineation however causes severe radiation damage to nanostructures which is further compounded during later post-processing such as reactive ion etching. Consequently, finished nanostructures become replete with traps, vacancies, spurious charges and surface states. To circumvent this problem, we are developing a ``gentle`` electrochemical technique for the fabrication of periodic quantum dot arrays. It does not damage the structures through harsh processing steps, offers a minimum feature size down to {approximately} 40 {Angstrom}, allows the fabrication of structures on non-planar surfaces (e.g. spherical or cylindrical substrates), is amenable to mass production (millions of wafers can be processed simultaneously) and is potentially orders of magnitude cheaper than conventional nanofabrication. This paper describes initial results and show that this technique bears significant promise for future applications in nanostructure synthesis.

  9. Coupling Impedance of a Periodic Array of Diaphragms (Erratum)

    SciTech Connect

    Stupakov, G.V.; /SLAC

    2012-05-24

    A method is presented for calculating the high-frequency longitudinal and transverse coupling impedances in a periodic array of diaphragms in a circular perfectly conducting pipe. The method is based on Weinstein's theory of diffraction of a plane electromagnetic wave on a stack of halfplanes. Using Weinstein's solution, it is shown that the problem of finding the beam field in the pipe reduces to an effective boundary condition at the radius of the diaphragms that couples the longitudinal electric field with the azimuthal magnetic one. Solving Maxwell's equations with this boundary condition leads to simple formulae for Z{sub long} and Z{sub tr}. A good agreement with a numerical solution of the problem found by other authors is demonstrated.

  10. Coupling impedance of a periodic array of diaphragms

    SciTech Connect

    Stupakov, G.V.

    1995-06-01

    A method is presented for calculating the high-frequency longitudinal and transverse coupling impedances in a periodic array of diaphragms in a circular perfectly conducting pipe. The method is based on Weinstein`s theory of diffraction of a plane electromagnetic wave on a stack of halfplanes. Using Weinstein`s solution, it is shown that the problem of finding the beam field in the pipe reduces to an effective boundary condition at the radius of the diaphragms that couples the longitudinal electric field with the azimuthal magnetic one. Solving Maxwell`s equations with this boundary condition leads to simple formulae for Z{sub long} and Z{sub tr}. A good agreement with a numerical solution of the problem found by other authors is demonstrated.

  11. Sleep as spatiotemporal integration of biological processes that evolved to periodically reinforce neurodynamic and metabolic homeostasis: The 2m3d paradigm of sleep.

    PubMed

    Mader, Edward Claro; Mader, Annie Cielo Llave

    2016-08-15

    Sleep continues to perplex scientists and researchers. Despite decades of sleep research, we still lack a clear understanding of the biological functions and evolution of sleep. In this review, we will examine sleep from a functional and phylogenetic perspective and describe some important conceptual gaps in understanding sleep. Classical theories of the biology and evolution of sleep emphasize sensory activation, energy balance, and metabolic homeostasis. Advances in electrophysiology, functional neuroimaging, and neuroplasticity allow us to view sleep within the framework of neural dynamics. With this paradigm shift, we have come to realize the importance of neurodynamic homeostasis in shaping the biology of sleep. Evidently, animals sleep to achieve neurodynamic and metabolic homeostasis. We are not aware of any framework for understanding sleep where neurodynamic, metabolic, homeostatic, chronophasic, and afferent variables are all taken into account. This motivated us to propose the two-mode three-drive (2m3d) paradigm of sleep. In the 2m3d paradigm, local neurodynamic/metabolic (N/M) processes switch between two modes-m0 and m1-in response to three drives-afferent, chronophasic, and homeostatic. The spatiotemporal integration of local m0/m1 operations gives rise to the global states of sleep and wakefulness. As a framework of evolution, the 2m3d paradigm allows us to view sleep as a robust adaptive strategy that evolved so animals can periodically reinforce neurodynamic and metabolic homeostasis while remaining sensitive to their internal and external environment. PMID:27423566

  12. 3D crustal structure and long-period ground motions from a M9.0 megathrust earthquake in the Pacific Northwest region

    NASA Astrophysics Data System (ADS)

    Olsen, Kim B.; Stephenson, William J.; Geisselmeyer, Andreas

    2008-04-01

    We have developed a community velocity model for the Pacific Northwest region from northern California to southern Canada and carried out the first 3D simulation of a Mw 9.0 megathrust earthquake rupturing along the Cascadia subduction zone using a parallel supercomputer. A long-period (<0.5 Hz) source model was designed by mapping the inversion results for the December 26, 2004 Sumatra-Andaman earthquake (Han et al., Science 313(5787):658-662, 2006) onto the Cascadia subduction zone. Representative peak ground velocities for the metropolitan centers of the region include 42 cm/s in the Seattle area and 8-20 cm/s in the Tacoma, Olympia, Vancouver, and Portland areas. Combined with an extended duration of the shaking up to 5 min, these long-period ground motions may inflict significant damage on the built environment, in particular on the highrises in downtown Seattle.

  13. 3D crustal structure and long-period ground motions from a M9.0 megathrust earthquake in the Pacific Northwest region

    USGS Publications Warehouse

    Olsen, K.B.; Stephenson, W.J.; Geisselmeyer, A.

    2008-01-01

    We have developed a community velocity model for the Pacific Northwest region from northern California to southern Canada and carried out the first 3D simulation of a Mw 9.0 megathrust earthquake rupturing along the Cascadia subduction zone using a parallel supercomputer. A long-period (<0.5 Hz) source model was designed by mapping the inversion results for the December 26, 2004 Sumatra–Andaman earthquake (Han et al., Science 313(5787):658–662, 2006) onto the Cascadia subduction zone. Representative peak ground velocities for the metropolitan centers of the region include 42 cm/s in the Seattle area and 8–20 cm/s in the Tacoma, Olympia, Vancouver, and Portland areas. Combined with an extended duration of the shaking up to 5 min, these long-period ground motions may inflict significant damage on the built environment, in particular on the highrises in downtown Seattle.

  14. One-step growth of 3D CoNi2S4 nanorods and cross-linked NiCo2S4 nanosheet arrays on carbon paper as anodes for high-performance lithium ion batteries.

    PubMed

    Yang, Weiwei; Chen, Liang; Yang, Jie; Zhang, Xiang; Fang, Chun; Chen, Zhiling; Huang, Lin; Liu, Jianguo; Zhou, Yong; Zou, Zhigang

    2016-04-01

    3D CoNi2S4 and cross-linked NiCo2S4 arrays have been grown on carbon paper (CP) using a one-step hydrothermal method. The 3D cross-linked structure provides a convenient channel for electron and lithium-ion (Li(+)) transport and performs a facile strain relaxation during cycling, exhibits high capacity, excellent rate capability and superior cycle performance. PMID:27001486

  15. Low-Cost Fabrication of Centimetre-Scale Periodic Arrays of Single Plasmid DNA Molecules

    PubMed Central

    Kirkland, Brett; Wang, Zhibin; Zhang, Peipei; Takebayashi, Shin-ichiro; Lenhert, Steven; Gilbert, David M.

    2013-01-01

    We report development of a low-cost method to generate a centimetre-scale periodic array of single plasmid DNA of 11 kilobase pairs. The arrayed DNA is amenable to enzymatic and physical manipulation. PMID:23824041

  16. A SiPM-based isotropic-3D PET detector X'tal cube with a three-dimensional array of 1 mm(3) crystals.

    PubMed

    Yamaya, Taiga; Mitsuhashi, Takayuki; Matsumoto, Takahiro; Inadama, Naoko; Nishikido, Fumihiko; Yoshida, Eiji; Murayama, Hideo; Kawai, Hideyuki; Suga, Mikio; Watanabe, Mitsuo

    2011-11-01

    We are developing a novel, general purpose isotropic-3D PET detector X'tal cube which has high spatial resolution in all three dimensions. The research challenge for this detector is implementing effective detection of scintillation photons by covering six faces of a segmented crystal block with silicon photomultipliers (SiPMs). In this paper, we developed the second prototype of the X'tal cube for a proof-of-concept. We aimed at realizing an ultimate detector with 1.0 mm(3) cubic crystals, in contrast to our previous development using 3.0 mm(3) cubic crystals. The crystal block was composed of a 16 × 16 × 16 array of lutetium gadolinium oxyorthosilicate (LGSO) crystals 0.993 × 0.993 × 0.993 mm(3) in size. The crystals were optically glued together without inserting any reflector inside and 96 multi-pixel photon counters (MPPCs, S10931-50P, i.e. six faces each with a 4 × 4 array of MPPCs), each having a sensitive area of 3.0 × 3.0 mm(2), were optically coupled to the surfaces of the crystal block. Almost all 4096 crystals were identified through Anger-type calculation due to the finely adjusted reflector sheets inserted between the crystal block and light guides. The reflector sheets, which formed a belt of 0.5 mm width, were placed to cover half of the crystals of the second rows from the edges in order to improve identification performance of the crystals near the edges. Energy resolution of 12.7% was obtained at 511 keV with almost uniform light output for all crystal segments thanks to the effective detection of the scintillation photons. PMID:21971079

  17. A SiPM-based isotropic-3D PET detector X'tal cube with a three-dimensional array of 1 mm3 crystals

    NASA Astrophysics Data System (ADS)

    Yamaya, Taiga; Mitsuhashi, Takayuki; Matsumoto, Takahiro; Inadama, Naoko; Nishikido, Fumihiko; Yoshida, Eiji; Murayama, Hideo; Kawai, Hideyuki; Suga, Mikio; Watanabe, Mitsuo

    2011-11-01

    We are developing a novel, general purpose isotropic-3D PET detector X'tal cube which has high spatial resolution in all three dimensions. The research challenge for this detector is implementing effective detection of scintillation photons by covering six faces of a segmented crystal block with silicon photomultipliers (SiPMs). In this paper, we developed the second prototype of the X'tal cube for a proof-of-concept. We aimed at realizing an ultimate detector with 1.0 mm3 cubic crystals, in contrast to our previous development using 3.0 mm3 cubic crystals. The crystal block was composed of a 16 × 16 × 16 array of lutetium gadolinium oxyorthosilicate (LGSO) crystals 0.993 × 0.993 × 0.993 mm3 in size. The crystals were optically glued together without inserting any reflector inside and 96 multi-pixel photon counters (MPPCs, S10931-50P, i.e. six faces each with a 4 × 4 array of MPPCs), each having a sensitive area of 3.0 × 3.0 mm2, were optically coupled to the surfaces of the crystal block. Almost all 4096 crystals were identified through Anger-type calculation due to the finely adjusted reflector sheets inserted between the crystal block and light guides. The reflector sheets, which formed a belt of 0.5 mm width, were placed to cover half of the crystals of the second rows from the edges in order to improve identification performance of the crystals near the edges. Energy resolution of 12.7% was obtained at 511 keV with almost uniform light output for all crystal segments thanks to the effective detection of the scintillation photons.

  18. Collisionless electron heating in periodic arrays of inductively coupled plasmas

    SciTech Connect

    Czarnetzki, U.; Tarnev, Kh.

    2014-12-15

    A novel mechanism of collisionless heating in large planar arrays of small inductive coils operated at radio frequencies is presented. In contrast to the well-known case of non-local heating related to the transversal conductivity, when the electrons move perpendicular to the planar coil, we investigate the problem of electrons moving in a plane parallel to the coils. Two types of periodic structures are studied. Resonance velocities where heating is efficient are calculated analytically by solving the Vlasov equation. Certain scaling parameters are identified. The concept is further investigated by a single particle simulation based on the ergodic principle and combined with a Monte Carlo code allowing for collisions with Argon atoms. Resonances, energy exchange, and distribution functions are obtained. The analytical results are confirmed by the numerical simulation. Pressure and electric field dependences are studied. Stochastic heating is found to be most efficient when the electron mean free path exceeds the size of a single coil cell. Then the mean energy increases approximately exponentially with the electric field amplitude.

  19. FPGA architectures for electronically scanned wide-band RF beams using 3-D FIR/IIR digital filters for rectangular array aperture receivers

    NASA Astrophysics Data System (ADS)

    Wijayaratna, Sewwandi; Madanayake, Arjuna; Beall, Brandon D.; Bruton, Len T.

    2014-05-01

    Real-time digital implementation of three-dimensional (3-D) infinite impulse response (IIR) beam filters are discussed. The 3-D IIR filter building blocks have filter coefficients, which are defined using algebraic closed-form expressions that are functions of desired beam personalities, such as the look-direction of the aperture, the bandwidth and sampling frequency of interest, inter antenna spacing, and 3dB beam size. Real-time steering of such 3-D beam filters are obtained by proposed calculation of filter coefficients. Application specific computing units for rapidly calculating the 3-D IIR filter coefficients at nanosecond speed potentially allows fast real-time tracking of low radar cross section (RCS) objects at close range. Proposed design consists of 3-D IIR beam filter with 4 4 antenna grid and the filter coefficient generation block in separate FPGAs. The hardware is designed and co-simulated using a Xilinx Virtex-6 XC6VLX240T FPGA. The 3-D filter operates over 90 MHz and filter coefficient computing structure can operate at up to 145 MHz.

  20. Infrared-induced variation of the magnetic properties of a magnetoplasmonic film with a 3D sub-micron periodic triangular roof-type antireflection structure

    NASA Astrophysics Data System (ADS)

    Tian, Junlong; Zhang, Wang; Huang, Yiqiao; Liu, Qinglei; Wang, Yuhua; Zhang, Zhijian; Zhang, Di

    2015-01-01

    A carbon-matrix nickel composite magnetoplasmonic film with a 3D sub-micron periodic triangular roof-type antireflection structure (SPTAS) was fabricated via a simple and promising method that combines chemosynthesis with biomimetic techniques. The Troides helena (Linnaeus) forewing (T_FW) was chosen as the biomimetic template. The carbon-matrix Ni wing fabricated via electroless Ni deposition for 6 h (CNMF_6h) exhibits enhanced infrared absorption. Over a wavelength range (888-2500 nm), the enhancement of the infrared absorption of CNMF_6h is up to 1.85 times compared with the T_FW. Furthermore, infrared excitation induces a photothermal effect that results in variation in the magnetic properties of the carbon-matrix Ni wing. The magnetic properties were also confirmed using atomic force microscopy (AFM) and magnetic force microscopy (MFM). The good correlation between the AFM and MFM images demonstrates that the surface of the SPTAS of CNMF_6h exhibits strong magnetic properties. The infrared induced photothermal effect that results in magnetic variation is promising for use in the design of novel magnetoplasmonic films with potential applications in infrared information recording and heat-assisted magnetic recording.

  1. Infrared-induced variation of the magnetic properties of a magnetoplasmonic film with a 3D sub-micron periodic triangular roof-type antireflection structure.

    PubMed

    Tian, Junlong; Zhang, Wang; Huang, Yiqiao; Liu, Qinglei; Wang, Yuhua; Zhang, Zhijian; Zhang, Di

    2015-01-01

    A carbon-matrix nickel composite magnetoplasmonic film with a 3D sub-micron periodic triangular roof-type antireflection structure (SPTAS) was fabricated via a simple and promising method that combines chemosynthesis with biomimetic techniques. The Troides helena (Linnaeus) forewing (T_FW) was chosen as the biomimetic template. The carbon-matrix Ni wing fabricated via electroless Ni deposition for 6 h (CNMF_6h) exhibits enhanced infrared absorption. Over a wavelength range (888-2500 nm), the enhancement of the infrared absorption of CNMF_6h is up to 1.85 times compared with the T_FW. Furthermore, infrared excitation induces a photothermal effect that results in variation in the magnetic properties of the carbon-matrix Ni wing. The magnetic properties were also confirmed using atomic force microscopy (AFM) and magnetic force microscopy (MFM). The good correlation between the AFM and MFM images demonstrates that the surface of the SPTAS of CNMF_6h exhibits strong magnetic properties. The infrared induced photothermal effect that results in magnetic variation is promising for use in the design of novel magnetoplasmonic films with potential applications in infrared information recording and heat-assisted magnetic recording. PMID:25620787

  2. Infrared-induced variation of the magnetic properties of a magnetoplasmonic film with a 3D sub-micron periodic triangular roof-type antireflection structure

    PubMed Central

    Tian, Junlong; Zhang, Wang; Huang, Yiqiao; Liu, Qinglei; Wang, Yuhua; Zhang, Zhijian; Zhang, Di

    2015-01-01

    A carbon-matrix nickel composite magnetoplasmonic film with a 3D sub-micron periodic triangular roof-type antireflection structure (SPTAS) was fabricated via a simple and promising method that combines chemosynthesis with biomimetic techniques. The Troides helena (Linnaeus) forewing (T_FW) was chosen as the biomimetic template. The carbon-matrix Ni wing fabricated via electroless Ni deposition for 6 h (CNMF_6h) exhibits enhanced infrared absorption. Over a wavelength range (888–2500 nm), the enhancement of the infrared absorption of CNMF_6h is up to 1.85 times compared with the T_FW. Furthermore, infrared excitation induces a photothermal effect that results in variation in the magnetic properties of the carbon-matrix Ni wing. The magnetic properties were also confirmed using atomic force microscopy (AFM) and magnetic force microscopy (MFM). The good correlation between the AFM and MFM images demonstrates that the surface of the SPTAS of CNMF_6h exhibits strong magnetic properties. The infrared induced photothermal effect that results in magnetic variation is promising for use in the design of novel magnetoplasmonic films with potential applications in infrared information recording and heat-assisted magnetic recording. PMID:25620787

  3. Transmission resonances and Bloch states for a periodic array of delta function potentials

    NASA Astrophysics Data System (ADS)

    Berman, P. R.

    2013-03-01

    The relationship between transmission resonances and Bloch states for a periodic array consisting of N delta function potentials is discussed. The transmission resonances are derived for matter waves incident on the periodic array, while the Bloch states are calculated using periodic boundary conditions for the array. It is shown that approximately half of the transmission resonances map into pairs of degenerate Bloch states. Wave functions are shown for both the transmission resonances and the Bloch states for arrays of five and six delta function potentials. The origin of the band structure of the Bloch states is interpreted in terms of the wave functions and eigenenergies for a particle confined to move on a ring, subjected to a periodic array of delta function potentials on the ring.

  4. Polaritons in a nonideal periodic array of microcavities

    NASA Astrophysics Data System (ADS)

    Rumyantsev, Vladimir; Fedorov, Stanislav; Gumennyk, Kostyantyn; Sychanova, Marina; Kavokin, Alexey

    2016-01-01

    The virtual crystal approximation is employed to numerically model the propagation of localized electromagnetic excitations through a two-dimensional array of coupled microcavities containing atomic clusters (quantum dots). The constructed model allows for the presence of defects (absence of cavities and/or quantum dots) at certain sites of the supercrystal. We derive the dispersion relations for polaritonic modes as functions of defect concentrations. This permits to evaluate the densities of states of polaritons and their effective masses as well as the band gaps for any prescribed values of defect concentrations.

  5. Transport and Dispersion of Nanoparticles in Periodic Nanopost Arrays

    SciTech Connect

    He, Kai; Retterer, Scott T; Srijanto, Bernadeta R; Conrad, Jacinta; Krishnamoorti, Ramanan

    2014-01-01

    Nanoparticles transported through highly confined porous media exhibit faster breakthrough than small molecule tracers. Despite important technological applications in advanced materials, human health, energy, and environment, the microscale mechanisms leading to early breakthrough have not been identified. Here, we measure dispersion of nanoparticles at the singleparticle scale in regular arrays of nanoposts and show that for highly confined flows of dilute suspensions of nanoparticles the longitudinal and transverse velocities exhibit distinct scaling behaviors. The distributions of transverse particle velocities become narrower and more non-Gaussian when the particles are strongly confined. As a result, the transverse dispersion of highly confined nanoparticles at low P clet numbers is significantly less important than longitudinal dispersion, leading to early breakthrough. This finding suggests a fundamental mechanism by which to control dispersion and thereby improve efficacy of nanoparticles applied for advanced polymer nanocomposites, drug delivery, hydrocarbon production, and environmental remediation.

  6. Characteristics of block-periodic phased-array antennas with circular polarization of the radiated field

    NASA Astrophysics Data System (ADS)

    Likhoded, Iu. V.; Mironnikov, A. S.

    1990-02-01

    The paper presents results of a numerical investigation of the directivity characteristics of a block-periodic waveguide phased-array antenna with circular polarization of the radiated field. The advantages of this array from the viewpoint of maximining the ellipticity coefficent of the radiated field in the scanning sector are pointed out.

  7. fVisiOn: 360-degree viewable glasses-free tabletop 3D display composed of conical screen and modular projector arrays.

    PubMed

    Yoshida, Shunsuke

    2016-06-13

    A novel glasses-free tabletop 3D display to float virtual objects on a flat tabletop surface is proposed. This method employs circularly arranged projectors and a conical rear-projection screen that serves as an anisotropic diffuser. Its practical implementation installs them beneath a round table and produces horizontal parallax in a circumferential direction without the use of high speed or a moving apparatus. Our prototype can display full-color, 5-cm-tall 3D characters on the table. Multiple viewers can share and enjoy its real-time animation from any angle of 360 degrees with appropriate perspectives as if the animated figures were present. PMID:27410336

  8. Diffusion model for Knudsen-type compressor composed of periodic arrays of circular cylinders

    NASA Astrophysics Data System (ADS)

    Taguchi, Satoshi

    2010-10-01

    A rarefied gas flow in a long porous channel having a periodic structure that is consisting of alternately arranged porous media and gaps, the former of which contains a periodic array of parallel circular cylinders, is considered for the case in which the channel is infinitely wide. The cylinder arrays have a periodic temperature distribution with the same period as the structure. Under the assumption that the length of each cylinder array and that of each gap are much larger than the period of the cylinders in the array, a fluid-dynamic system describing the overall behavior of the gas in the channel is derived from the kinetic system composed of the Bhatnagar-Gross-Krook equation and the diffuse reflection boundary condition. The derived system is composed of a diffusion model for each cylinder array, whose isothermal version has been reported previously [S. Taguchi and P. Charrier, Phys. Fluids 20, 067103 (2008)], a set of fluid-dynamic equations for each gap, and the macroscopic connection conditions at each junction between an array and a gap. Then, the fluid-dynamic system is applied to a long channel consisting of many cylinder arrays and gaps. Some numerical results demonstrating the pumping effect of the flow are presented.

  9. Construction and 3-D computer modeling of connector arrays with tetragonal to decagonal transition induced by pRNA of phi29 DNA-packaging motor.

    PubMed

    Guo, Yin Yin; Blocker, Forrest; Xiao, Feng; Guo, Peixuan

    2005-06-01

    The bottom-up assembly of patterned arrays is an exciting and important area in current nanotechnology. Arrays can be engineered to serve as components in chips for a virtually inexhaustible list of applications ranging from disease diagnosis to ultrahigh-density data storage. In attempting to achieve this goal, a number of methods to facilitate array design and production have been developed. Cloning and expression of the gene coding for the connector of the bacterial virus phi29 DNA-packaging motor, overproduction of the gene products, and the in vitro construction of large-scale carpet-like arrays composed of connector are described in this report. The stability of the arrays under various conditions, including varied pH, temperature and ionic strength, was tested. The addition of packaging RNA (pRNA) into the array caused a dramatic shift in array structure, and resulted in the conversion of tetragonal arrays into larger decagonal structures comprised of both protein and RNA. RNase digestion confirmed that the conformational shift was caused by pRNA, and that RNA was present in the decagons. As has been demonstrated in biomotors, conformational shift of motor components can generate force for motor motion. The conformational shift reported here can be utilized as a potential force-generating mechanism for the construction of nanomachines. Three-dimensional computer models of the constructed arrays were also produced using a variety of connector building blocks with or without the N- or C-terminal sequence, which is absent from the current published crystal structures. Both the connector array and the decagon are ideal candidates to be used as templates to build patterned suprastructures in nanotechnology. PMID:16060143

  10. Euro3D Science Conference

    NASA Astrophysics Data System (ADS)

    Walsh, J. R.

    2004-02-01

    The Euro3D RTN is an EU funded Research Training Network to foster the exploitation of 3D spectroscopy in Europe. 3D spectroscopy is a general term for spectroscopy of an area of the sky and derives its name from its two spatial + one spectral dimensions. There are an increasing number of instruments which use integral field devices to achieve spectroscopy of an area of the sky, either using lens arrays, optical fibres or image slicers, to pack spectra of multiple pixels on the sky (``spaxels'') onto a 2D detector. On account of the large volume of data and the special methods required to reduce and analyse 3D data, there are only a few centres of expertise and these are mostly involved with instrument developments. There is a perceived lack of expertise in 3D spectroscopy spread though the astronomical community and its use in the armoury of the observational astronomer is viewed as being highly specialised. For precisely this reason the Euro3D RTN was proposed to train young researchers in this area and develop user tools to widen the experience with this particular type of data in Europe. The Euro3D RTN is coordinated by Martin M. Roth (Astrophysikalisches Institut Potsdam) and has been running since July 2002. The first Euro3D science conference was held in Cambridge, UK from 22 to 23 May 2003. The main emphasis of the conference was, in keeping with the RTN, to expose the work of the young post-docs who are funded by the RTN. In addition the team members from the eleven European institutes involved in Euro3D also presented instrumental and observational developments. The conference was organized by Andy Bunker and held at the Institute of Astronomy. There were over thirty participants and 26 talks covered the whole range of application of 3D techniques. The science ranged from Galactic planetary nebulae and globular clusters to kinematics of nearby galaxies out to objects at high redshift. Several talks were devoted to reporting recent observations with newly

  11. The role of Fabry–Perot resonance for a periodic array of gold nano-slits

    NASA Astrophysics Data System (ADS)

    Zhang, Siwen; Sun, Xiaodong; Wu, Feng; Yang, Jianing

    2016-06-01

    Comprehensive investigations of electromagnetic enhancement and transmittance by a periodic array of gold nano-slits are presented. Rigorous numerical data can be well predicted by a simple Fabry-Perot model. By virtue of the model, the role of Fabry-Perot resonance that enables giant electromagnetic enhancement and high transmittance by a gold nano-slit array is studied. Distinct impacts of array period and slit width on electromagnetic enhancement and those on transmittance are explored. Numerical results imply that contributions of electromagnetic enhancement and transmittance should be considered together in determining the actual enhanced effect of sample signals in surface-enhanced Raman scattering application.

  12. FEM-based linear inverse modeling using a 3D source array to image magma chambers with free geometry. Application to InSAR data from Rabaul Caldera (PNG).

    NASA Astrophysics Data System (ADS)

    Ronchin, Erika; Masterlark, Timothy; Dawson, John; Saunders, Steve; Martí Molist, Joan

    2015-04-01

    In this study, we present a method to fully integrate a family of finite element models (FEMs) into the regularized linear inversion of InSAR data collected at Rabaul caldera (PNG) between February 2007 and December 2010. During this period the caldera experienced a long-term steady subsidence that characterized surface movement both inside the caldera and outside, on its western side. The inversion is based on an array of FEM sources in the sense that the Green's function matrix is a library of forward numerical displacement solutions generated by the sources of an array common to all FEMs. Each entry of the library is the LOS surface displacement generated by injecting a unity mass of fluid, of known density and bulk modulus, into a different source cavity of the array for each FEM. By using FEMs, we are taking advantage of their capability of including topography and heterogeneous distribution of elastic material properties. All FEMs of the family share the same mesh in which only one source is activated at the time by removing the corresponding elements and applying the unity fluid flux. The domain therefore only needs to be discretized once. This precludes remeshing for each activated source, thus reducing computational requirements, often a downside of FEM-based inversions. Without imposing an a-priori source, the method allows us to identify, from a least-squares standpoint, a complex distribution of fluid flux (or change in pressure) with a 3D free geometry within the source array, as dictated by the data. The results of applying the proposed inversion to Rabaul InSAR data show a shallow magmatic system under the caldera made of two interconnected lobes located at the two opposite sides of the caldera. These lobes could be consistent with feeding reservoirs of the ongoing Tavuvur volcano eruption of andesitic products, on the eastern side, and of the past Vulcan volcano eruptions of more evolved materials, on the western side. The interconnection and

  13. Europeana and 3D

    NASA Astrophysics Data System (ADS)

    Pletinckx, D.

    2011-09-01

    The current 3D hype creates a lot of interest in 3D. People go to 3D movies, but are we ready to use 3D in our homes, in our offices, in our communication? Are we ready to deliver real 3D to a general public and use interactive 3D in a meaningful way to enjoy, learn, communicate? The CARARE project is realising this for the moment in the domain of monuments and archaeology, so that real 3D of archaeological sites and European monuments will be available to the general public by 2012. There are several aspects to this endeavour. First of all is the technical aspect of flawlessly delivering 3D content over all platforms and operating systems, without installing software. We have currently a working solution in PDF, but HTML5 will probably be the future. Secondly, there is still little knowledge on how to create 3D learning objects, 3D tourist information or 3D scholarly communication. We are still in a prototype phase when it comes to integrate 3D objects in physical or virtual museums. Nevertheless, Europeana has a tremendous potential as a multi-facetted virtual museum. Finally, 3D has a large potential to act as a hub of information, linking to related 2D imagery, texts, video, sound. We describe how to create such rich, explorable 3D objects that can be used intuitively by the generic Europeana user and what metadata is needed to support the semantic linking.

  14. Gold Nanorods: Evaporative Self-Assembly of Gold Nanorods into Macroscopic 3D Plasmonic Superlattice Arrays (Adv. Mater. 13/2016).

    PubMed

    Li, Penghui; Li, Yong; Zhou, Zhang-Kai; Tang, Siying; Yu, Xue-Feng; Xiao, Shu; Wu, Zhongzhen; Xiao, Quanlan; Zhao, Yuetao; Wang, Huaiyu; Chu, Paul K

    2016-04-01

    On page 2511, X.-F. Yu, P. K. Chu, and co-workers demonstrate the successful fabrication of millimeter-scale three-dimensional superlattice arrays consisting of dense, regular, and vertically aligned gold nanorods by the evaporative self-assembly method. The excellent performance in surface-enhanced Raman scattering indicates applications in plasmonic substrates. PMID:27037942

  15. Periodically Aligned Si Nanopillar Arrays as Efficient Antireflection Layers for Solar Cell Applications

    PubMed Central

    2010-01-01

    Periodically aligned Si nanopillar (PASiNP) arrays were fabricated on Si substrate via a silver-catalyzed chemical etching process using the diameter-reduced polystyrene spheres as mask. The typical sub-wavelength structure of PASiNP arrays had excellent antireflection property with a low reflection loss of 2.84% for incident light within the wavelength range of 200–1,000 nm. The solar cell incorporated with the PASiNP arrays exhibited a power conversion efficiency (PCE) of ~9.24% with a short circuit current density (JSC) of ~29.5 mA/cm2 without using any extra surface passivation technique. The high PCE of PASiNP array-based solar cell was attributed to the excellent antireflection property of the special periodical Si nanostructure. PMID:21124636

  16. Transmittance of long-wavelength infrared surface plasmon by hexagonal periodic metal hole arrays

    NASA Astrophysics Data System (ADS)

    Lee, Byungwoo; Kwak, Hoe Min; Kim, Ha Sul

    2016-03-01

    For long wave length infrared transmission, a surface plasmonic device, having the periodic subwavelength metal hole array on Si substrate, was fabricated using photo-lithography and electron beam evaporation. The maximum transmitted wavelength was adjustable arbitrarily as a function of the period hole arrays. The maximum transmittance was measured 70.3% at 15.4 μm with a plasmonic device composed of a pitch of 5 μm and hole arrays of 3 μm. When the hole size became larger than a half pitch of the hole array, the transmitted infrared spectrum was split into two peaks. The surface plasmon mode of the six degenerated (1,0) Ag/Si was split from three to five modes depending on the incident beam angle. The blue and red wavelength shifts were measured at the same time.

  17. 3D Ta/TaO x /TiO2/Ti synaptic array and linearity tuning of weight update for hardware neural network applications.

    PubMed

    Wang, I-Ting; Chang, Chih-Cheng; Chiu, Li-Wen; Chou, Teyuh; Hou, Tuo-Hung

    2016-09-01

    The implementation of highly anticipated hardware neural networks (HNNs) hinges largely on the successful development of a low-power, high-density, and reliable analog electronic synaptic array. In this study, we demonstrate a two-layer Ta/TaO x /TiO2/Ti cross-point synaptic array that emulates the high-density three-dimensional network architecture of human brains. Excellent uniformity and reproducibility among intralayer and interlayer cells were realized. Moreover, at least 50 analog synaptic weight states could be precisely controlled with minimal drifting during a cycling endurance test of 5000 training pulses at an operating voltage of 3 V. We also propose a new state-independent bipolar-pulse-training scheme to improve the linearity of weight updates. The improved linearity considerably enhances the fault tolerance of HNNs, thus improving the training accuracy. PMID:27483492

  18. Performance and field tests of a handheld Compton camera using 3-D position-sensitive scintillators coupled to multi-pixel photon counter arrays

    NASA Astrophysics Data System (ADS)

    Kishimoto, A.; Kataoka, J.; Nishiyama, T.; Fujita, T.; Takeuchi, K.; Okochi, H.; Ogata, H.; Kuroshima, H.; Ohsuka, S.; Nakamura, S.; Hirayanagi, M.; Adachi, S.; Uchiyama, T.; Suzuki, H.

    2014-11-01

    After the nuclear disaster in Fukushima, radiation decontamination has become particularly urgent. To help identify radiation hotspots and ensure effective decontamination operation, we have developed a novel Compton camera based on Ce-doped Gd3Al2Ga3O12 scintillators and multi-pixel photon counter (MPPC) arrays. Even though its sensitivity is several times better than that of other cameras being tested in Fukushima, we introduce a depth-of-interaction (DOI) method to further improve the angular resolution. For gamma rays, the DOI information, in addition to 2-D position, is obtained by measuring the pulse-height ratio of the MPPC arrays coupled to ends of the scintillator. We present the detailed performance and results of various field tests conducted in Fukushima with the prototype 2-D and DOI Compton cameras. Moreover, we demonstrate stereo measurement of gamma rays that enables measurement of not only direction but also approximate distance to radioactive hotspots.

  19. 3D Ta/TaO x /TiO2/Ti synaptic array and linearity tuning of weight update for hardware neural network applications

    NASA Astrophysics Data System (ADS)

    Wang, I.-Ting; Chang, Chih-Cheng; Chiu, Li-Wen; Chou, Teyuh; Hou, Tuo-Hung

    2016-09-01

    The implementation of highly anticipated hardware neural networks (HNNs) hinges largely on the successful development of a low-power, high-density, and reliable analog electronic synaptic array. In this study, we demonstrate a two-layer Ta/TaO x /TiO2/Ti cross-point synaptic array that emulates the high-density three-dimensional network architecture of human brains. Excellent uniformity and reproducibility among intralayer and interlayer cells were realized. Moreover, at least 50 analog synaptic weight states could be precisely controlled with minimal drifting during a cycling endurance test of 5000 training pulses at an operating voltage of 3 V. We also propose a new state-independent bipolar-pulse-training scheme to improve the linearity of weight updates. The improved linearity considerably enhances the fault tolerance of HNNs, thus improving the training accuracy.

  20. Down-hole seismic survey system with fiber-optic accelerometer sensor array for 3-dimensions vertical seismic profile (3D-VSP)

    NASA Astrophysics Data System (ADS)

    Zou, Qilin; Wang, Liwei; Pang, Meng; Tu, Dongsheng; Zhang, Min; Liao, Yanbiao

    2006-08-01

    We demonstrated a down-hole seismic survey system that can be applied in three dimensions vertical seismic profile (VSP) detection in petroleum exploration. The results of experiments show that the system has a dynamic measurement range of 80db (ratio of maximum to minimum value) and the total delay for signal collection, process and communication is less than 200ms @ 2k bit sample rates. An array consisting of six fiber-optic accelerometers (receivers) is applied in this system. Each receiver is comprised of three fiber-optic Michelson interferometers. In order to meet the requirements of high precision and real-time measurement, the high-speed DSP chips are employed to realize the algorithms of signal filters and Phase Generated Carrier (PGC) demodulation to obtain the seismic information. Multi-ARM CPUs are introduced into the system to design the fiber-optic accelerometer array controller and the receiver array local bus that are used for real-time data communication between the multi-level receivers and controller. The system interface for traditional ELIS Down-hole Instrument Bus (EDIB) is designed by the use of FPGA so that our system can attach to EDIB and cooperate with other instruments. The design and experiments of the system are given in this paper in detail.

  1. Concentration of broadband terahertz radiation using a periodic array of conically tapered apertures.

    PubMed

    Liu, Shuchang; Vardeny, Z Valy; Nahata, Ajay

    2013-05-20

    We describe the optical concentration properties of periodic arrays of conically tapered metallic apertures measured using terahertz (THz) time-domain spectroscopy. As a first step in this process, we optimize the geometrical properties of individual apertures, keeping the output aperture diameter fixed, and find that the optimal taper angle is 30°. A consequence of increasing the taper angle is that the effective cutoff frequency red shifts, which can be readily explained using conventional waveguide theory. We then fabricate and measure the transmission properties of a periodic (hexagonal) array of optimized tapered apertures. In contrast to periodic arrays of subwavelength apertures in thin metal films, which are characterized by narrowband transmission resonances associated with the periodic spacing, here we observe broadband enhanced transmission above the effective cutoff frequency. Further enhancement in the concentration capabilities of the array can be achieved by tilting the apertures towards the array center, although the optical throughput of individual tapered apertures is reduced with increasing tilt angle. Finally, we discuss possible future directions that utilize cascaded structures, as a means for obtaining further enhancement in the amplitude of the transmitted THz radiation. PMID:23736454

  2. 3D Finite Element Analysis of Particle-Reinforced Aluminum

    NASA Technical Reports Server (NTRS)

    Shen, H.; Lissenden, C. J.

    2002-01-01

    Deformation in particle-reinforced aluminum has been simulated using three distinct types of finite element model: a three-dimensional repeating unit cell, a three-dimensional multi-particle model, and two-dimensional multi-particle models. The repeating unit cell model represents a fictitious periodic cubic array of particles. The 3D multi-particle (3D-MP) model represents randomly placed and oriented particles. The 2D generalized plane strain multi-particle models were obtained from planar sections through the 3D-MP model. These models were used to study the tensile macroscopic stress-strain response and the associated stress and strain distributions in an elastoplastic matrix. The results indicate that the 2D model having a particle area fraction equal to the particle representative volume fraction of the 3D models predicted the same macroscopic stress-strain response as the 3D models. However, there are fluctuations in the particle area fraction in a representative volume element. As expected, predictions from 2D models having different particle area fractions do not agree with predictions from 3D models. More importantly, it was found that the microscopic stress and strain distributions from the 2D models do not agree with those from the 3D-MP model. Specifically, the plastic strain distribution predicted by the 2D model is banded along lines inclined at 45 deg from the loading axis while the 3D model prediction is not. Additionally, the triaxial stress and maximum principal stress distributions predicted by 2D and 3D models do not agree. Thus, it appears necessary to use a multi-particle 3D model to accurately predict material responses that depend on local effects, such as strain-to-failure, fracture toughness, and fatigue life.

  3. 3d-3d correspondence revisited

    NASA Astrophysics Data System (ADS)

    Chung, Hee-Joong; Dimofte, Tudor; Gukov, Sergei; Sułkowski, Piotr

    2016-04-01

    In fivebrane compactifications on 3-manifolds, we point out the importance of all flat connections in the proper definition of the effective 3d {N}=2 theory. The Lagrangians of some theories with the desired properties can be constructed with the help of homological knot invariants that categorify colored Jones polynomials. Higgsing the full 3d theories constructed this way recovers theories found previously by Dimofte-Gaiotto-Gukov. We also consider the cutting and gluing of 3-manifolds along smooth boundaries and the role played by all flat connections in this operation.

  4. Sound transmission in a duct with a side-branch tube array mounted periodically.

    PubMed

    Wang, Xiaonan; Zhu, Wenying; Zhou, Yude

    2016-06-01

    This paper presents a theoretical study of sound propagation in a duct with a tube array flush-mounted periodically. The underlying wave interaction is analyzed by the transfer matrix method, and validated by the numerical simulation. With identical tubes, a particular situation is observed that the periodic distance and the tube length are "matched," leading to a strong coupling effect by Bragg reflection and tube resonance, resulting in a wide stopband in low frequency. Even when the tubes in the array are not identical, the Bragg reflection can still work to broaden the stopband which was originally contributed by tube resonances. PMID:27369173

  5. Cartilage Repair and Subchondral Bone Migration Using 3D Printing Osteochondral Composites: A One-Year-Period Study in Rabbit Trochlea

    PubMed Central

    Li, Dichen; Wang, Kunzheng; Hao, Dingjun; Bian, Weiguo; He, Jiankang; Jin, Zhongmin

    2014-01-01

    Increasing evidences show that subchondral bone may play a significant role in the repair or progression of cartilage damage in situ. However, the exact change of subchondral bone during osteochondral repair is still poorly understood. In this paper, biphasic osteochondral composite scaffolds were fabricated by 3D printing technology using PEG hydrogel and β-TCP ceramic and then implanted in rabbit trochlea within a critical size defect model. Animals were euthanized at 1, 2, 4, 8, 16, 24, and 52 weeks after implantation. Histological results showed that hyaline-like cartilage formed along with white smooth surface and invisible margin at 24 weeks postoperatively, typical tidemark formation at 52 weeks. The repaired subchondral bone formed from 16 to 52 weeks in a “flow like” manner from surrounding bone to the defect center gradually. Statistical analysis illustrated that both subchondral bone volume and migration area percentage were highly correlated with the gross appearance Wayne score of repaired cartilage. Therefore, subchondral bone migration is related to cartilage repair for critical size osteochondral defects. Furthermore, the subchondral bone remodeling proceeds in a “flow like” manner and repaired cartilage with tidemark implies that the biphasic PEG/β-TCP composites fabricated by 3D printing provides a feasible strategy for osteochondral tissue engineering application. PMID:25177697

  6. Remote 3D Medical Consultation

    NASA Astrophysics Data System (ADS)

    Welch, Greg; Sonnenwald, Diane H.; Fuchs, Henry; Cairns, Bruce; Mayer-Patel, Ketan; Yang, Ruigang; State, Andrei; Towles, Herman; Ilie, Adrian; Krishnan, Srinivas; Söderholm, Hanna M.

    Two-dimensional (2D) video-based telemedical consultation has been explored widely in the past 15-20 years. Two issues that seem to arise in most relevant case studies are the difficulty associated with obtaining the desired 2D camera views, and poor depth perception. To address these problems we are exploring the use of a small array of cameras to synthesize a spatially continuous range of dynamic three-dimensional (3D) views of a remote environment and events. The 3D views can be sent across wired or wireless networks to remote viewers with fixed displays or mobile devices such as a personal digital assistant (PDA). The viewpoints could be specified manually or automatically via user head or PDA tracking, giving the remote viewer virtual head- or hand-slaved (PDA-based) remote cameras for mono or stereo viewing. We call this idea remote 3D medical consultation (3DMC). In this article we motivate and explain the vision for 3D medical consultation; we describe the relevant computer vision/graphics, display, and networking research; we present a proof-of-concept prototype system; and we present some early experimental results supporting the general hypothesis that 3D remote medical consultation could offer benefits over conventional 2D televideo.

  7. Templated fabrication of periodic arrays of metallic and silicon nanorings with complex nanostructures

    NASA Astrophysics Data System (ADS)

    Liu, Xuefeng; Gozubenli, Numan; Choi, Baeck; Jiang, Peng; Meagher, Timothy; Jiang, Bin

    2015-02-01

    Here we report a scalable colloidal templating approach for fabricating periodic arrays of metallic and silicon nanorings with complex nanostructures. Non-close-packed monolayer silica colloidal crystal prepared by a simple spin-coating technology is first used as template for making periodic arrays of mushroom-like composite nanostructures consisting of silica spherical caps and polymer stems. Subsequent metal sputtering and reactive ion etching lead to the formation of ordered asymmetric nickel nanorings which can be further utilized as etching masks for patterning periodic arrays of symmetric silicon nanorings. Moreover, periodic arrays of metallic and silicon concentric double nanorings can be fabricated by using the asymmetric nickel nanorings as templates. We have also demonstrated that gold concentric double nanorings show strong surface-enhanced Raman scattering (SERS) with a SERS enhancement factor of ˜9.5 × 107 from adsorbed benzenethiol molecules. The SERS enhancement and the electric field amplitude distribution surrounding gold concentric double nanorings have been calculated by using finite element electromagnetic modeling. This new colloidal templating technique is compatible with standard microfabrication and enables wafer-scale production of a variety of periodic nanorings with hierarchical structures that could find important technological applications in plasmonic and magnetic devices.

  8. A semi-log-periodic array of spheroidal nanoelements: broadbanding nanoantennas

    NASA Astrophysics Data System (ADS)

    Khosravi, M.; Sadeghzadeh, R. A.; Abrishamian, M. S.

    2014-12-01

    Nanoantenna arrays can offer unique possibilities for large local-field enhancement, high directivity, and also wavelength tunability over a wide spectral range. In this paper, a semi-log-periodic array of nanospheroidal elements has been studied, which exhibits a narrower beam and also a higher electric field enhancement in comparison with an equal size, equally distanced array of the same element. Through the numerical simulations, it has been presented that the suggested array is of a great potential for improvement of the directivity as well as the electric field enhancement over similar designs. Moreover, a considerable change has been observed in the electric field through gradual transformation of elements from sphere to very thin rod. Next, the effect of geometrical parameters on local-field enhancement has been investigated as a complementary job. Finally, it has been demonstrated that adjusting the number of elements can provide a narrower beam.

  9. Broadband sound attenuation on a periodic array of rectangular profile holes in plate

    NASA Astrophysics Data System (ADS)

    Moiseyenko, R. P.; Pennec, Y.; Marchal, R.; Bonello, B.; Djafari-Rouhani, B.

    2014-04-01

    Transmission of acoustic waves through a periodic array of sub-wavelength slits or holes have been studied in several recent works in relation with physical phenomena such as resonant (extraordinary) transmission, broadband sound shielding or acoustic induced transparency (AIT). In this work, we present for the first time the study of analogous phenomena for Lamb waves propagating in a thin plate. We study the transmission through one or two rows of a periodic array constituted by thin bridges separated by rectangular holes. When two rows of such an array are considered, the choice of the distance between both rows allows the realization of a broadband attenuation up to 99% in the transmission. These investigations should have implications for sound isolation, filtering and sensing applications.

  10. 3D and Education

    NASA Astrophysics Data System (ADS)

    Meulien Ohlmann, Odile

    2013-02-01

    Today the industry offers a chain of 3D products. Learning to "read" and to "create in 3D" becomes an issue of education of primary importance. 25 years professional experience in France, the United States and Germany, Odile Meulien set up a personal method of initiation to 3D creation that entails the spatial/temporal experience of the holographic visual. She will present some different tools and techniques used for this learning, their advantages and disadvantages, programs and issues of educational policies, constraints and expectations related to the development of new techniques for 3D imaging. Although the creation of display holograms is very much reduced compared to the creation of the 90ies, the holographic concept is spreading in all scientific, social, and artistic activities of our present time. She will also raise many questions: What means 3D? Is it communication? Is it perception? How the seeing and none seeing is interferes? What else has to be taken in consideration to communicate in 3D? How to handle the non visible relations of moving objects with subjects? Does this transform our model of exchange with others? What kind of interaction this has with our everyday life? Then come more practical questions: How to learn creating 3D visualization, to learn 3D grammar, 3D language, 3D thinking? What for? At what level? In which matter? for whom?

  11. Optical properties of silicon nanocrystals covered by periodic array of gold nanowires

    NASA Astrophysics Data System (ADS)

    Dyakov, S. A.; Zhigunov, D. M.; Marinins, A.; Shcherbakov, M. R.; Fedyanin, A. A.; Vorontsov, A. S.; Kashkarov, P. K.; Popov, S.; Qiu, M.; Zacharias, M.; Tikhodeev, S. G.; Gippius, N. A.

    2016-05-01

    Extinction and photoluminescence spectra are experimentally and theoretically studied for a periodic array of gold nanowires deposited on top of a dielectric substrate containing silicon nanocrystals. Quasiguided modes are observed in the substrate resulting in modification of optical properties of silicon nanocrystals. Our calculations of extinction and photoluminescence spectra are in good agreement with experimental results. The periodicity provides a powerful tool for achieving a high photoluminescence outcoupling efficiency of silicon nanocrystals.

  12. A dimensional comparison between embedded 3D-printed and silicon microchannels

    NASA Astrophysics Data System (ADS)

    O'Connor, J.; Punch, J.; Jeffers, N.; Stafford, J.

    2014-07-01

    The subject of this paper is the dimensional characterization of embedded microchannel arrays created using contemporary 3D-printing fabrication techniques. Conventional microchannel arrays, fabricated using deep reactive ion etching techniques (DRIE) and wet-etching (KOH), are used as a benchmark for comparison. Rectangular and trapezoidal cross-sectional shapes were investigated. The channel arrays were 3D-printed in vertical and horizontal directions, to examine the influence of print orientation on channel characteristics. The 3D-printed channels were benchmarked against Silicon channels in terms of the following dimensional characteristics: cross-sectional area (CSA), perimeter, and surface profiles. The 3D-printed microchannel arrays demonstrated variances in CSA of 6.6-20% with the vertical printing approach yielding greater dimensional conformity than the horizontal approach. The measured CSA and perimeter of the vertical channels were smaller than the nominal dimensions, while the horizontal channels were larger in both CSA and perimeter due to additional side-wall roughness present throughout the channel length. This side-wall roughness caused significant shape distortion. Surface profile measurements revealed that the base wall roughness was approximately the resolution of current 3D-printers. A spatial periodicity was found along the channel length which appeared at different frequencies for each channel array. This paper concludes that vertical 3D-printing is superior to the horizontal printing approach, in terms of both dimensional fidelity and shape conformity and can be applied in microfluidic device applications.

  13. Surface-enhanced Raman scattering of crystal violets from periodic array of gold nanocylinders

    NASA Astrophysics Data System (ADS)

    Bi, Gang; Wang, Li; Cai, Chunfeng; Ueno, Kosei; Misawa, Hiroaki; Qiu, Jianrong

    2014-09-01

    The periodic arrays of gold nanocylinder with 121 nm in diameter, 6.3 nm in gap, and 34 nm in thickness are fabricated on glass by electron-beam lithography and lift-off techniques. Some crystal violet molecules are coated on the array by using the dipping and drawing method. In addition, the surface-enhanced Raman scattering (SERS) spectra of these samples with and without gold nanocylinder arrays are characterized specifically. The largest enhancement factor is obtained when the excitation wavelength corresponds to the peak wavelength of localized surface plasmon resonance (LSPR). The density functional theory and the finite-difference time-domain method are used for the calculations of the extinction spectrum of the arrays and Raman spectra of the crystal violet, respectively. These results unambiguously demonstrate that the periodic arrays of gold nanocylinder have good and effective surface-enhanced properties for Raman scattering of crystal violets, and they also show that the excitation wavelength corresponding to the peak one of the LSPR is one of the major reasons causing SERS.

  14. A 3-D velocity structure in and around the Miura peninsula, Japan, using a 3-component off-line seismographic array.

    NASA Astrophysics Data System (ADS)

    Kawamura, T.; Hirata, N.; Sato, H.; Onishi, M.; Noda, K.; Saito, H.

    2004-12-01

    A deep seismic profiling around the Metropolitan Tokyo region, the Kanto district, started in 2002 under the project titled as the Regional Characterization of the Crust in Metropolitan Areas for Prediction of Strong Ground Motion. The deep seismic profiling, Tokyo Bay 2003, was performed along the major axis of the Tokyo Bay. Because the seismic line in the Miura peninsula passes through a densely populated area, we have a low signal-to-noise ratio data due to the cultural noise. Thus, in addition to the conventional reflection profiling, we deployed 51 off-line recorders with a 3-compornent geophone of 4.5 Hz at carefully selected, quiet receiver points. During 90 days, we had continuous records including many shot signals produced by vibrators on land and air-guns at the bay area. These data provided far-offset first arrival signals and wide angle reflections. We focus on the common receiver gather records of the Tokyo Bay 2003 off-line stations data to identify first arrival and wide angle phases. We applied the first arrival tomography method using a finite difference travel time solver (Hole, 1992) to those data to obtain a 3-D P-wave velocity structure of the uppermost crust along the profile. We obtained a velocity model in and around the Miura peninsula as follows: Across the Tokyo Bay, near surface is a layer with velocities of 2.0-2.5 km/s. A low velocity area corresponds to the fore-arc basin sediment (post Early Miocene) which extends to a depth of approximately 4 km. High velocity patches are located at a depth of approximately 6 km under the Miura peninsula, which we interpreted as Pre-Neogene basement rocks. Finally, the velocity structure obtained by the tomography analysis is used to improve the processing of the reflection profiling data to clarify the deeper structure in the peninsula, including a good velocity constraint for a pre-stack migration of the reflection profiling data.

  15. Time domain spectral method and its application on antenna array and PCB trace with periodic roughness

    NASA Astrophysics Data System (ADS)

    Wang, Minshen

    The primary interest of the electromagnetic behavior of a periodic structure is in its near field and far field. However, it is still numerically difficult to analyze either one in the time domain. The primary goal of this dissertation is to develop corresponding time domain technique to analyze two topics. The first one is to evaluate the far field of a realistic, large antenna array using an efficient method. The second one is to evaluate the propagation characteristic of a commercially available printed circuit board (PCB) with intentional roughness. Both of which are hot topics in the antenna and signal integrity (SI) society respectively; however, none of them have ever been solved in the time domain. To efficiently evaluate the far field pattern of a realistically large antenna array, the spectral domain method and the reciprocity theorem are implemented in the finite difference time domain (FDTD) technique to avoid the simulation of the near field. By taking advantage of the periodic boundary condition (PBC), the proposed method demonstrates its capability to speed up far field evaluation from hours to minutes. Good agreement of the results is provided for various cases: circular antenna array, arbitrary feeding array, and highly directional leaky wave antenna, etc. Periodic structure modeling with finite sized feedings is developed by the array scanning method (ASM) implemented in the FDTD technique. The minimally coupled electric and magnetic co-mingled antenna array is evaluated by the method. Moreover, a commercially available PCB with very small roughness is modeled by the ASM-FDTD and the propagation characteristic is evaluated. Both are evaluated by time domain method for the first time. Efficiency in terms of memory and computing time is shown for this method and parallelization in the future is proposed.

  16. 3D TiO2@Ni(OH)2 Core-shell Arrays with Tunable Nanostructure for Hybrid Supercapacitor Application

    PubMed Central

    Ke, Qingqing; Zheng, Minrui; Liu, Huajun; Guan, Cao; Mao, Lu; Wang, John

    2015-01-01

    Three dimensional hierarchical nanostructures have attracted great attention for electrochemical energy storage applications. In this work, self-supported TiO2@Ni(OH)2 core-shell nanowire arrays are prepared on carbon fiber paper via the combination of hydrothermal synthesis and chemical bath deposition. In this core-shell hybrid, the morphology and wall size of the interconnected nanoflake shell of Ni(OH)2 can be tuned through adjusting the concentration of ammonia solution. Heterogeneous nucleation and subsequent oriented crystal growth are identified to be the synthesis mechanism affecting the nanostructure of the shell material, which consequently determines the electrochemical performance in both energy storage and charge transfer. Superior capabilities of 264 mAhg−1 at 1 A g−1 and 178 mAh g−1 at 10 A g−1 are achieved with the core-shell hybrids of the optimized structure. The asymmetric supercapacitor prototype, comprising of TiO2@Ni(OH)2 as the anode and mesoporous carbons (MCs) as the cathode, is shown to exhibit superior electrochemical performance with high energy and power densities. The present work provides a clear illustration of the structure-property relationship in nanocrystal synthesis and offers a potential strategy to enhance the battery type Ni(OH)2 electrode in a hybrid supercapacitor device. PMID:26353970

  17. 3D TiO2@Ni(OH)2 Core-shell Arrays with Tunable Nanostructure for Hybrid Supercapacitor Application

    NASA Astrophysics Data System (ADS)

    Ke, Qingqing; Zheng, Minrui; Liu, Huajun; Guan, Cao; Mao, Lu; Wang, John

    2015-09-01

    Three dimensional hierarchical nanostructures have attracted great attention for electrochemical energy storage applications. In this work, self-supported TiO2@Ni(OH)2 core-shell nanowire arrays are prepared on carbon fiber paper via the combination of hydrothermal synthesis and chemical bath deposition. In this core-shell hybrid, the morphology and wall size of the interconnected nanoflake shell of Ni(OH)2 can be tuned through adjusting the concentration of ammonia solution. Heterogeneous nucleation and subsequent oriented crystal growth are identified to be the synthesis mechanism affecting the nanostructure of the shell material, which consequently determines the electrochemical performance in both energy storage and charge transfer. Superior capabilities of 264 mAhg-1 at 1 A g-1 and 178 mAh g-1 at 10 A g-1 are achieved with the core-shell hybrids of the optimized structure. The asymmetric supercapacitor prototype, comprising of TiO2@Ni(OH)2 as the anode and mesoporous carbons (MCs) as the cathode, is shown to exhibit superior electrochemical performance with high energy and power densities. The present work provides a clear illustration of the structure-property relationship in nanocrystal synthesis and offers a potential strategy to enhance the battery type Ni(OH)2 electrode in a hybrid supercapacitor device.

  18. 3D TiO2@Ni(OH)2 Core-shell Arrays with Tunable Nanostructure for Hybrid Supercapacitor Application.

    PubMed

    Ke, Qingqing; Zheng, Minrui; Liu, Huajun; Guan, Cao; Mao, Lu; Wang, John

    2015-01-01

    Three dimensional hierarchical nanostructures have attracted great attention for electrochemical energy storage applications. In this work, self-supported TiO2@Ni(OH)2 core-shell nanowire arrays are prepared on carbon fiber paper via the combination of hydrothermal synthesis and chemical bath deposition. In this core-shell hybrid, the morphology and wall size of the interconnected nanoflake shell of Ni(OH)2 can be tuned through adjusting the concentration of ammonia solution. Heterogeneous nucleation and subsequent oriented crystal growth are identified to be the synthesis mechanism affecting the nanostructure of the shell material, which consequently determines the electrochemical performance in both energy storage and charge transfer. Superior capabilities of 264 mAh g(-1) at 1 A g(-1) and 178 mAh g(-1) at 10 A g(-1) are achieved with the core-shell hybrids of the optimized structure. The asymmetric supercapacitor prototype, comprising of TiO2@Ni(OH)2 as the anode and mesoporous carbons (MCs) as the cathode, is shown to exhibit superior electrochemical performance with high energy and power densities. The present work provides a clear illustration of the structure-property relationship in nanocrystal synthesis and offers a potential strategy to enhance the battery type Ni(OH)2 electrode in a hybrid supercapacitor device. PMID:26353970

  19. 3D Imaging.

    ERIC Educational Resources Information Center

    Hastings, S. K.

    2002-01-01

    Discusses 3 D imaging as it relates to digital representations in virtual library collections. Highlights include X-ray computed tomography (X-ray CT); the National Science Foundation (NSF) Digital Library Initiatives; output peripherals; image retrieval systems, including metadata; and applications of 3 D imaging for libraries and museums. (LRW)

  20. Optoplasmonics: hybridization in 3D

    NASA Astrophysics Data System (ADS)

    Rosa, L.; Gervinskas, G.; Žukauskas, A.; Malinauskas, M.; Brasselet, E.; Juodkazis, S.

    2013-12-01

    Femtosecond laser fabrication has been used to make hybrid refractive and di ractive micro-optical elements in photo-polymer SZ2080. For applications in micro- uidics, axicon lenses were fabricated (both single and arrays), for generation of light intensity patterns extending through the entire depth of a typically tens-of-micrometers deep channel. Further hybridisation of an axicon with a plasmonic slot is fabricated and demonstrated nu- merically. Spiralling chiral grooves were inscribed into a 100-nm-thick gold coating sputtered over polymerized micro-axicon lenses, using a focused ion beam. This demonstrates possibility of hybridisation between optical and plasmonic 3D micro-optical elements. Numerical modelling of optical performance by 3D-FDTD method is presented.

  1. Periodically striped films produced from super-aligned carbon nanotube arrays.

    PubMed

    Liu, Kai; Sun, Yinghui; Liu, Peng; Wang, Jiaping; Li, Qunqing; Fan, Shoushan; Jiang, Kaili

    2009-08-19

    We report a novel way to draw films from super-aligned carbon nanotube arrays at large drawing angles. The obtained super-aligned carbon nanotube films have a periodically striped configuration with alternating thinner and thicker film sections, and the width of the stripes is equal to the height of the original arrays. Compared with ordinary uniform films, the striped films provide a better platform for understanding the mechanism of spinning films from arrays because carbon nanotube junctions are easily observed and identified at the boundary of the stripes. Further studies show that the carbon nanotube junctions are bottleneck positions for thermal conduction and mechanical strength of the film, but do not limit its electrical conduction. These films can be utilized as striped and high-degree polarized light emission sources. Our results will be valuable for new applications and future large-scale production of tunable super-aligned carbon nanotube films. PMID:19636102

  2. Electromagnetic enhancement by a periodic array of nanogrooves in a metallic substrate.

    PubMed

    Zhang, Siwen; Liu, Haitao; Mu, Guoguang

    2011-05-01

    We present comprehensive investigations of the electromagnetic enhancement by a periodic array of rectangular nanogrooves in a metallic substrate. The impacts of array parameters and of illumination conditions on the enhanced electric-field intensity are explored using fully vectorial methods. The calculations are performed mainly for gold and for the visible and infrared wavelengths. The fully vectorial results are reproduced and explained by a simple Fabry-Perot model. Compared with the case of a single groove, the electric-field enhancement of the groove array is found to be much higher by almost 1 order of magnitude, which is shown to be related to the excitation of surface plasmon polaritons with the aid of the model. Practical considerations of a finite groove number and of a finite groove length are also provided. PMID:21532700

  3. Cu-PDC-bpa solid coordination frameworks (PDC=2,5-pyrindinedicarboxylate; bpa=1,2-DI(4-pyridil)ethane)): 2D and 3D structural flexibility producing a 3-c herringbone array next to ideal

    SciTech Connect

    Llano-Tomé, Francisco; Bazán, Begoña; Urtiaga, Miren-Karmele; Barandika, Gotzone; Antonia Señarís-Rodríguez, M.; and others

    2015-10-15

    Combination of polycarboxylate anions and dipyridyl ligands is an effective strategy to produce solid coordination frameworks (SCF) which are crystalline materials based on connections between metal ions through organic ligands. In this context, this work is focused on two novel Cu{sup II}-based SCFs exhibiting PDC (2,5-pyridinedicarboxylate) and bpa (1,2-di(4-pyridyl)ethane), being the first structures reported in literature containing both ligands. Chemical formula are [Cu{sub 2}[(PDC){sub 2}(bpa)(H{sub 2}O){sub 2}]·3H{sub 2}O·DMF (1), and [Cu{sub 2}(PDC){sub 2}(bpa)(H{sub 2}O){sub 2}]·7H{sub 2}O (2), where DMF is dimethylformamide. Compounds 1 and 2 have been characterized by means of X-ray diffraction (XRD), infrared spectroscopy (IR), thermogravimetric (TG) analysis, differential thermal analysis (DTA) and dielectric measurements. The crystallographic analysis revealed that compounds 1 and 2 can be described as herringbone-type layers formed by helicoidal Cu-PDC-Cu chains connected through bpa ligands. Solvent molecules are crystallized between the layers, providing the inter-layer connections through hydrogen bonds. Differences between both compounds are attributable to the flexibility of bpa (in 2D) as well as to the 3D packing of the layers which is solvent dependent. This fact results in the fact that compound 2 is the most regular 3-c herringbone array reported so far. The structural dynamism of these networks is responsible for the crystalline to-amorphous to-crystalline (CAC) transformation from compound 1 to compound 2. Crystallochemical features for both compounds have also been studied and compared to similar 3-connected herringbone-arrays. - Graphical abstract: Cu-PDC-bpa 3-c herringbone arrays. - Highlights: • The most ideal herringbone array reported so far is a Cu-PDC-bpa SCF. • Conformational freedom of bpa results in 2D and 3D flexibility of the SCFs. • The flexibility of the SCFs is related to a phase transformation. • Dielectric

  4. Ultra-high-density 3D DNA arrays within nanoporous biocompatible membranes for single-molecule-level detection and purification of circulating nucleic acids

    NASA Astrophysics Data System (ADS)

    Aramesh, M.; Shimoni, O.; Fox, K.; Karle, T. J.; Lohrmann, A.; Ostrikov, K.; Prawer, S.; Cervenka, J.

    2015-03-01

    alumina membrane. The few nanometer-thick, yet perfect and continuous DLC-coating confers the chemical stability and biocompatibility of the sensor, allowing its direct application in biological conditions. The selective detection is based on complementary hybridization of a fluorescently-tagged circulating cancer oncomarker (a 21-mer nucleic acid) with covalently immobilized DNA on the surface of the membrane. The captured DNAs are detected in the nanoporous structure of the sensor using confocal scanning laser microscopy. The flow-through membrane sensor demonstrates broad-range sensitivity, spanning from 1015 molecules per cm2 down to single molecules, which is several orders of magnitude improvement compared to the flat DNA microarrays. Our study suggests that these flow-through type nanoporous sensors represent a new powerful platform for large volume sampling and ultrasensitive detection of different chemical biomarkers. Electronic supplementary information (ESI) available: Time dependent fluorescence intensity measurements, photoluminescence decay on flat and nanoporous arrays, fluorophore time traces and photoluminescence of AAO and DLC-AAO. See DOI: 10.1039/c4nr07351g

  5. Metal-organic frameworks from zinc sulfite clusters, chains, and sheets: 4-connected, (3,4)-connected 3-D frameworks and 2-D arrays of catenane-like interlocking rings.

    PubMed

    Nguyen, Dan-Tam; Chew, Emily; Zhang, Qichun; Choi, Alice; Bu, Xianhui

    2006-12-25

    Even though open-framework solids have been made in a variety of compositions such as silicates, phosphates, germanates, borates, and phosphites, few are known that are based on trigonal-pyramidal sulfite anions. We report here the first synthetic and structural studies of metal-organic framework materials in the zinc sulfite composition. It is demonstrated here that Zn2+ and SO32- can form various neutral inorganic subunits that can be 0-D clusters, 1-D chains, or 2-D sheets. These inorganic subunits of different dimensionality can subsequently be connected into extended frameworks of higher dimensionality through bifunctional ligands. In (ZnSO3)2en, infinite corrugated ZnSO3 layers are pillared by ethylenediamine (en) molecules into a 3-D network that can be classified as a (3,4)-connected net based on tetrahedral Zn nodes and trigonal-pyramidal S nodes. In (ZnSO3)pip, infinite ZnSO3 chains are cross-linked with piperazine molecules into a 3-D framework that can be classified as 4-connected net based on tetrahedral Zn nodes only. In (ZnSO3)2(TMDPy)2, (ZnSO3)2 dimers are doubly bridged by trimethylenedipyridine molecules into an infinite chain with a string of circles. Each circle along the chain is interlocked with another circle from a chain in the perpendicular direction, creating a 2-D pattern with an infinite-square array of catenane-like units. PMID:17173428

  6. Phononic thermal resistance due to a finite periodic array of nano-scatterers

    NASA Astrophysics Data System (ADS)

    Trang Nghiêm, T. T.; Chapuis, Pierre-Olivier

    2016-07-01

    The wave property of phonons is employed to explore the thermal transport across a finite periodic array of nano-scatterers such as circular and triangular holes. As thermal phonons are generated in all directions, we study their transmission through a single array for both normal and oblique incidences, using a linear dispersionless time-dependent acoustic frame in a two-dimensional system. Roughness effects can be directly considered within the computations without relying on approximate analytical formulae. Analysis by spatio-temporal Fourier transform allows us to observe the diffraction effects and the conversion of polarization. Frequency-dependent energy transmission coefficients are computed for symmetric and asymmetric objects that are both subject to reciprocity. We demonstrate that the phononic array acts as an efficient thermal barrier by applying the theory of thermal boundary (Kapitza) resistances to arrays of smooth scattering holes in silicon for an exemplifying periodicity of 10 nm in the 5-100 K temperature range. It is observed that the associated thermal conductance has the same temperature dependence as that without phononic filtering.

  7. Surface plasmon enhanced absorption and suppressed transmission in periodic arrays of graphene ribbons

    NASA Astrophysics Data System (ADS)

    Nikitin, A. Yu.; Guinea, F.; Garcia-Vidal, F. J.; Martin-Moreno, L.

    2012-02-01

    Resonance diffraction in the periodic array of graphene microribbons is theoretically studied following a recent experiment [L. Ju , Nature Nanotech.1748-338710.1038/nnano.2011.146 6, 630 (2011)]. Systematic studies over a wide range of parameters are presented. It is shown that a much richer resonant picture would be observable for higher relaxation times of charge carriers: More resonances appear and transmission can be totally suppressed. The comparison with the absorption cross-section of a single ribbon shows that the resonant features of the periodic array are associated with leaky plasmonic modes. The longest-wavelength resonance provides the highest visibility of the transmission dip and has the strongest spectral shift and broadening with respect to the single-ribbon resonance, due to collective effects.

  8. TRACE 3-D documentation

    SciTech Connect

    Crandall, K.R.

    1987-08-01

    TRACE 3-D is an interactive beam-dynamics program that calculates the envelopes of a bunched beam, including linear space-charge forces, through a user-defined transport system. TRACE 3-D provides an immediate graphics display of the envelopes and the phase-space ellipses and allows nine types of beam-matching options. This report describes the beam-dynamics calculations and gives detailed instruction for using the code. Several examples are described in detail.

  9. Light Trapping Enhancement in a Thin Film with 2D Conformal Periodic Hexagonal Arrays.

    PubMed

    Yang, Xi; Zhou, Suqiong; Wang, Dan; He, Jian; Zhou, Jun; Li, Xiaofeng; Gao, Pingqi; Ye, Jichun

    2015-12-01

    Applying a periodic light trapping array is an effective method to improve the optical properties in thin-film solar cells. In this work, we experimentally and theoretically investigate the light trapping properties of two-dimensional periodic hexagonal arrays in the framework of a conformal amorphous silicon film. Compared with the planar reference, the double-sided conformal periodic structures with all feature periodicities of sub-wavelength (300 nm), mid-wavelength (640 nm), and infrared wavelength (2300 nm) show significant broadband absorption enhancements under wide angles. The films with an optimum periodicity of 300 nm exhibit outstanding antireflection and excellent trade-off between light scattering performance and parasitic absorption loss. The average absorption of the optimum structure with a thickness of 160 nm is 64.8 %, which is much larger than the planar counterpart of 38.5 %. The methodology applied in this work can be generalized to rational design of other types of high-performance thin-film photovoltaic devices based on a broad range of materials. PMID:26153124

  10. Light Trapping Enhancement in a Thin Film with 2D Conformal Periodic Hexagonal Arrays

    NASA Astrophysics Data System (ADS)

    Yang, Xi; Zhou, Suqiong; Wang, Dan; He, Jian; Zhou, Jun; Li, Xiaofeng; Gao, Pingqi; Ye, Jichun

    2015-07-01

    Applying a periodic light trapping array is an effective method to improve the optical properties in thin-film solar cells. In this work, we experimentally and theoretically investigate the light trapping properties of two-dimensional periodic hexagonal arrays in the framework of a conformal amorphous silicon film. Compared with the planar reference, the double-sided conformal periodic structures with all feature periodicities of sub-wavelength (300 nm), mid-wavelength (640 nm), and infrared wavelength (2300 nm) show significant broadband absorption enhancements under wide angles. The films with an optimum periodicity of 300 nm exhibit outstanding antireflection and excellent trade-off between light scattering performance and parasitic absorption loss. The average absorption of the optimum structure with a thickness of 160 nm is 64.8 %, which is much larger than the planar counterpart of 38.5 %. The methodology applied in this work can be generalized to rational design of other types of high-performance thin-film photovoltaic devices based on a broad range of materials.

  11. 3D ultrafast ultrasound imaging in vivo

    NASA Astrophysics Data System (ADS)

    Provost, Jean; Papadacci, Clement; Esteban Arango, Juan; Imbault, Marion; Fink, Mathias; Gennisson, Jean-Luc; Tanter, Mickael; Pernot, Mathieu

    2014-10-01

    Very high frame rate ultrasound imaging has recently allowed for the extension of the applications of echography to new fields of study such as the functional imaging of the brain, cardiac electrophysiology, and the quantitative imaging of the intrinsic mechanical properties of tumors, to name a few, non-invasively and in real time. In this study, we present the first implementation of Ultrafast Ultrasound Imaging in 3D based on the use of either diverging or plane waves emanating from a sparse virtual array located behind the probe. It achieves high contrast and resolution while maintaining imaging rates of thousands of volumes per second. A customized portable ultrasound system was developed to sample 1024 independent channels and to drive a 32  ×  32 matrix-array probe. Its ability to track in 3D transient phenomena occurring in the millisecond range within a single ultrafast acquisition was demonstrated for 3D Shear-Wave Imaging, 3D Ultrafast Doppler Imaging, and, finally, 3D Ultrafast combined Tissue and Flow Doppler Imaging. The propagation of shear waves was tracked in a phantom and used to characterize its stiffness. 3D Ultrafast Doppler was used to obtain 3D maps of Pulsed Doppler, Color Doppler, and Power Doppler quantities in a single acquisition and revealed, at thousands of volumes per second, the complex 3D flow patterns occurring in the ventricles of the human heart during an entire cardiac cycle, as well as the 3D in vivo interaction of blood flow and wall motion during the pulse wave in the carotid at the bifurcation. This study demonstrates the potential of 3D Ultrafast Ultrasound Imaging for the 3D mapping of stiffness, tissue motion, and flow in humans in vivo and promises new clinical applications of ultrasound with reduced intra—and inter-observer variability.

  12. Investigating Global 3-D Shear-Wave Anisotropy in the Earth's Mantle from Free Oscillations, Body Waves, Surface Waves and Long-period Waveforms

    NASA Astrophysics Data System (ADS)

    Moulik, P.; Ekstrom, G.

    2012-12-01

    We have developed a framework that can be used to investigate anisotropic velocity, density and anelastic heterogeneity in the Earth's mantle using a wide spectrum (0.3-50 mHz) of seismological observables. We start with the extensive dataset of surface-wave phase anomalies, long-period waveforms, and body-wave travel times collected by Kustowski et al. (2008) for the development of the global model S362ANI. The additional data included in our analysis are splitting functions of spheroidal and toroidal modes, which are analogous to phase velocity maps at low frequencies. We include in this set of observations a new dataset containing the splitting functions of 56 spheroidal fundamental modes and overtones, measured by Deuss et al. (2011, 2012) using data from large recent earthquakes. Apart from providing unique constraints on the long-wavelength elastic and density structure in the mantle, the overtone splitting data are especially sensitive to the velocity (and anisotropic) structure in the transition zone and in the deeper mantle. The detection of anisotropy, a marker of flow, in the transition zone has implications for our understanding of mantle convection. Our forward modeling of the splitting functions, like the other types of data, includes the effects of radial anisotropy (Mochizuki, 1986). We show that the upper-mantle shear-wave anisotropy of S362ANI generates a clear contribution to the splitting functions of the modes that are sensitive to the upper-mantle structure. We explore the tradeoffs between fitting the mode splitting functions and the travel-times of body waves that turn in the transition zone or in the lower mantle (e.g. SS), while observing that the waveforms and the surface wave phase-anomalies provide complementary information about the mantle. Our experiments suggest that the splitting data are sufficiently sensitive to the anisotropy in the mantle such that their inclusion may provide a better depth resolution of the anisotropic shear

  13. Particle collision dynamics in periodic asymmetric microfluidic obstacle arrays for rare cell capture

    NASA Astrophysics Data System (ADS)

    Smith, James; Gleghorn, Jason; Kirby, Brian

    2012-11-01

    Particle-obstacle collision dynamics in periodic microfluidic obstacle arrays are presented in the context of microfluidic devices for the capture of rare cells, such as circulating tumor cells (CTCs). A coupled CFD-particle advection simulation was used to calculate particle trajectories for low Reynolds number, low Stokes number flows. A rich range of deterministic transport modes was identified as a function of array geometry, and the resulting particle size-dependent collision rate highlights the usefulness of these arrays for high-efficiency, high-purity rare cell capture. A reduced-order model, assuming unidirectional flow and infinitesimal obstacles, captures most of the details of transport in these systems with an O (104) computational saving; this model is a useful tool for rapidly exploring a large design space and optimizing geometries for a specific rare cell capture application. Results of the CFD simulations, reduced-order ballistic models, and experiments with polystyrene particles and cancer cells indicate that array geometry is central to rare cell capture and that simple models can be used to inform the design of these microfluidic devices. Present affiliation: Department of Chemical and Biological Engineering, Princeton University.

  14. Radiochromic 3D Detectors

    NASA Astrophysics Data System (ADS)

    Oldham, Mark

    2015-01-01

    Radiochromic materials exhibit a colour change when exposed to ionising radiation. Radiochromic film has been used for clinical dosimetry for many years and increasingly so recently, as films of higher sensitivities have become available. The two principle advantages of radiochromic dosimetry include greater tissue equivalence (radiologically) and the lack of requirement for development of the colour change. In a radiochromic material, the colour change arises direct from ionising interactions affecting dye molecules, without requiring any latent chemical, optical or thermal development, with important implications for increased accuracy and convenience. It is only relatively recently however, that 3D radiochromic dosimetry has become possible. In this article we review recent developments and the current state-of-the-art of 3D radiochromic dosimetry, and the potential for a more comprehensive solution for the verification of complex radiation therapy treatments, and 3D dose measurement in general.

  15. Optical scatterometry with analytic approaches applied to periodic nano-arrays including anisotropic layers

    NASA Astrophysics Data System (ADS)

    Abdulhalim, I.

    2007-06-01

    Optical scatterometry is being used as a powerful technique for measurement of sub-wavelength periodic structures. It is based on measuring the scattered signal and solving the inverse scattering problem. For periodic nano-arrays with feature size less than 100nm, it is possible to simplify the electromagnetic simulations using the Rytov near quasi-static approximation valid for feature periods only few times less than the wavelength. This is shown to be adequate for the determination of the structure parameters from the zero order reflected or transmitted waves and their polarization or ellipsometric properties. The validity of this approach is applied to lamellar nano-scale grating photo-resist lines on Si substrate. Formulation for structures containing anisotropic multilayers is presented using the 4x4 matrix approach.

  16. 3D Ultrafast Ultrasound Imaging In Vivo

    PubMed Central

    Provost, Jean; Papadacci, Clement; Arango, Juan Esteban; Imbault, Marion; Gennisson, Jean-Luc; Tanter, Mickael; Pernot, Mathieu

    2014-01-01

    Very high frame rate ultrasound imaging has recently allowed for the extension of the applications of echography to new fields of study such as the functional imaging of the brain, cardiac electrophysiology, and the quantitative real-time imaging of the intrinsic mechanical properties of tumors, to name a few, non-invasively and in real time. In this study, we present the first implementation of Ultrafast Ultrasound Imaging in three dimensions based on the use of either diverging or plane waves emanating from a sparse virtual array located behind the probe. It achieves high contrast and resolution while maintaining imaging rates of thousands of volumes per second. A customized portable ultrasound system was developed to sample 1024 independent channels and to drive a 32×32 matrix-array probe. Its capability to track in 3D transient phenomena occurring in the millisecond range within a single ultrafast acquisition was demonstrated for 3-D Shear-Wave Imaging, 3-D Ultrafast Doppler Imaging and finally 3D Ultrafast combined Tissue and Flow Doppler. The propagation of shear waves was tracked in a phantom and used to characterize its stiffness. 3-D Ultrafast Doppler was used to obtain 3-D maps of Pulsed Doppler, Color Doppler, and Power Doppler quantities in a single acquisition and revealed, for the first time, the complex 3-D flow patterns occurring in the ventricles of the human heart during an entire cardiac cycle, and the 3-D in vivo interaction of blood flow and wall motion during the pulse wave in the carotid at the bifurcation. This study demonstrates the potential of 3-D Ultrafast Ultrasound Imaging for the 3-D real-time mapping of stiffness, tissue motion, and flow in humans in vivo and promises new clinical applications of ultrasound with reduced intra- and inter-observer variability. PMID:25207828

  17. Bootstrapping 3D fermions

    NASA Astrophysics Data System (ADS)

    Iliesiu, Luca; Kos, Filip; Poland, David; Pufu, Silviu S.; Simmons-Duffin, David; Yacoby, Ran

    2016-03-01

    We study the conformal bootstrap for a 4-point function of fermions < ψψψψ> in 3D. We first introduce an embedding formalism for 3D spinors and compute the conformal blocks appearing in fermion 4-point functions. Using these results, we find general bounds on the dimensions of operators appearing in the ψ × ψ OPE, and also on the central charge C T . We observe features in our bounds that coincide with scaling dimensions in the GrossNeveu models at large N . We also speculate that other features could coincide with a fermionic CFT containing no relevant scalar operators.

  18. Driving an individual vortex in the presence of a periodic pinning array

    SciTech Connect

    Reichhardt, Charles; Reichhardt, Cynthia

    2009-01-01

    Recently it has been demonstrated experimentally that it is possible to manipulate an individual vortex in a type-II superconductor using a magnetic force microscope tip. Using numerical simulations, we investigate the dynamics of a single driven individual vortex in the presence of a periodic pinning array and other vortices. Remarkably, we find that the effective drag on the driven vortex is reduced at the matching fields, which is opposite from the behavior of the critical current when all the vortices are driven. We discuss this effect in the context of the type of dynamics that occur at matching and nonmatching fields.

  19. Broadband single-layered graphene absorber using periodic arrays of graphene ribbons with gradient width

    NASA Astrophysics Data System (ADS)

    Zhihong, Zhu; Chucai, Guo; Jianfa, Zhang; Ken, Liu; Xiaodong, Yuan; Shiqiao, Qin

    2015-01-01

    We demonstrate that a broadband single-layered graphene absorber can be obtained in the THz range using periodic arrays of chemically doped graphene ribbons with gradient width, supported on a dielectric film placed on a thick piece of metal. The working bandwidth of 90% absorption for this structure is as high as 1.3 THz with a central frequency of 3 THz. The broadband operation mechanism is a result of the varying continuous plasmon resonances occurring in graphene ribbons with gradient width. The operation wavelength can be expanded to the far-infrared range.

  20. Micro-contacting of single and periodically arrayed columnar silicon structures by focused ion beam techniques

    SciTech Connect

    Friedrich, F. Herfurth, N.; Teodoreanu, A.-M.; Boit, C.

    2014-06-16

    Micron-sized, periodic crystalline Silicon columns on glass substrate were electrically contacted with a transparent conductive oxide front contact and a focused ion beam processed local back contact. Individual column contacts as well as arrays of >100 contacted columns were processed. Current-voltage characteristics of the devices were determined. By comparison with characteristics obtained from adapted device simulation, the absorber defect density was reconstructed. The contacting scheme allows the fabrication of testing devices in order to evaluate the electronic potential of promising semiconductor microstructures.

  1. Bessel-like beam array formation by periodical arrangement of the polymeric round-tip microstructures.

    PubMed

    Stankevičius, Evaldas; Garliauskas, Mantas; Gedvilas, Mindaugas; Račiukaitis, Gediminas

    2015-11-01

    Here, we report the formation of Bessel-like beam array from periodic patterns fabricated by the four-beam interference lithography. Characteristics of the generated Bessel-like beams depend on geometrical parameters of the fabricated microaxicon-like structures, which can be easily controlled via the laser processing parameters. The output beam characteristics disclose the attributes of Bessel beams. The demonstrated method enables an easy fabrication of angular-tolerant wavefront detectors, optical tweezers, optical imaging systems or materials processing tools, having a broad range of applications. PMID:26561125

  2. Stress relaxation in dual ion beam sputtered Nb2O5 and SiO2 thin films: application in a Fabry-Pérot filter array with 3D nanoimprinted cavities

    NASA Astrophysics Data System (ADS)

    Ullah, Anayat; Wilke, Hans; Memon, Imran; Shen, Yannan; Nguyen, Duc Toan; Woidt, Carsten; Hillmer, Hartmut

    2015-05-01

    Miniaturized spectrometers can be implemented using Fabry-Pérot (FP) filter arrays. Such filters are defined by two parallel mirrors with a resonance cavity in between. For high optical quality, ion beam sputtered distributed Bragg reflectors (DBRs), with alternating high and low refractive index material pairs, can be used as the FP mirrors; while 3D nanoimprint technology provides an efficient way of implementing multiple organic FP cavities of different heights in a single step. However, the high residual stress in ion beam sputtered films results in poor adhesion between the DBR films and the organic polymer cavities, causing debonding of the DBR. Therefore, the residual stress of the ion beam sputtered films forming the DBRs must be reduced. Niobium pentoxide (Nb2O5) and silicon dioxide (SiO2) are used as the DBR materials in this work due to their high index contrast, resulting in high reflectivity for only a few alternating pairs. Stress relaxation in ion beam sputtered Nb2O5 and SiO2 films is achieved in this work by deposition under simultaneous high energy ion bombardment (oxygen and argon gas mixture) from a second ion source. Using this technique, the film density and hence compressive film stress for both Nb2O5 and SiO2 films is reduced without introducing any additional optical absorption in the films. FP filter arrays fabricated with stress reduced Nb2O5 and SiO2 as DBR films exhibit high optical and mechanical performance, with good adhesion between the films and the polymer cavity.

  3. Cu-PDC-bpa solid coordination frameworks (PDC=2,5-pyrindinedicarboxylate; bpa=1,2-DI(4-pyridil)ethane)): 2D and 3D structural flexibility producing a 3-c herringbone array next to ideal

    NASA Astrophysics Data System (ADS)

    Llano-Tomé, Francisco; Bazán, Begoña; Urtiaga, Miren-Karmele; Barandika, Gotzone; Antonia Señarís-Rodríguez, M.; Sánchez-Andújar, Manuel; Arriortua, María-Isabel

    2015-10-01

    Combination of polycarboxylate anions and dipyridyl ligands is an effective strategy to produce solid coordination frameworks (SCF) which are crystalline materials based on connections between metal ions through organic ligands. In this context, this work is focused on two novel CuII-based SCFs exhibiting PDC (2,5-pyridinedicarboxylate) and bpa (1,2-di(4-pyridyl)ethane), being the first structures reported in literature containing both ligands. Chemical formula are [Cu2[(PDC)2(bpa)(H2O)2]·3H2O·DMF (1), and [Cu2(PDC)2(bpa)(H2O)2]·7H2O (2), where DMF is dimethylformamide. Compounds 1 and 2 have been characterized by means of X-ray diffraction (XRD), infrared spectroscopy (IR), thermogravimetric (TG) analysis, differential thermal analysis (DTA) and dielectric measurements. The crystallographic analysis revealed that compounds 1 and 2 can be described as herringbone-type layers formed by helicoidal Cu-PDC-Cu chains connected through bpa ligands. Solvent molecules are crystallized between the layers, providing the inter-layer connections through hydrogen bonds. Differences between both compounds are attributable to the flexibility of bpa (in 2D) as well as to the 3D packing of the layers which is solvent dependent. This fact results in the fact that compound 2 is the most regular 3-c herringbone array reported so far. The structural dynamism of these networks is responsible for the crystalline to-amorphous to-crystalline (CAC) transformation from compound 1 to compound 2. Crystallochemical features for both compounds have also been studied and compared to similar 3-connected herringbone-arrays.

  4. Sensitive surface plasmon resonance enabled by templated periodic arrays of gold nanodonuts

    NASA Astrophysics Data System (ADS)

    Dou, Xuan; Lin, Yuh-Chieh; Choi, Baeck; Wu, Kedi; Jiang, Peng

    2016-05-01

    Here we report a simple and scalable colloidal lithography technology for fabricating periodic arrays of gold nanodonuts for sensitive surface plasmon resonance (SPR) analysis. This new bottom-up approach leverages a unique polymer wetting layer between a self-assembled, non-close-packed monolayer silica colloidal crystal and a silicon substrate to template ordered gold nanodonuts with tunable geometries over wafer-sized areas. The processes involved in this templating nanofabrication approach, including spin coating, oxygen plasma etching, and metal sputtering, are all compatible with standard microfabrication technologies. Specular reflection measurements reveal that the efficient electromagnetic coupling of the incident light with the tunable SPR modes of the templated gold nanodonut arrays enables good spectral tunability. Bulk refractive index sensing experiments show that a high SPR sensitivity of ∼758 nm per refractive index unit, which outperforms many plasmonic nanostructures fabricated by both top-down and bottom-up approaches, can be achieved using the templated gold nanodonut arrays. Numerical finite-difference time-domain simulations have also been performed to complement the optical characterization and the theoretical results match well with the experimental measurements.

  5. Sensitive surface plasmon resonance enabled by templated periodic arrays of gold nanodonuts.

    PubMed

    Dou, Xuan; Lin, Yuh-Chieh; Choi, Baeck; Wu, Kedi; Jiang, Peng

    2016-05-13

    Here we report a simple and scalable colloidal lithography technology for fabricating periodic arrays of gold nanodonuts for sensitive surface plasmon resonance (SPR) analysis. This new bottom-up approach leverages a unique polymer wetting layer between a self-assembled, non-close-packed monolayer silica colloidal crystal and a silicon substrate to template ordered gold nanodonuts with tunable geometries over wafer-sized areas. The processes involved in this templating nanofabrication approach, including spin coating, oxygen plasma etching, and metal sputtering, are all compatible with standard microfabrication technologies. Specular reflection measurements reveal that the efficient electromagnetic coupling of the incident light with the tunable SPR modes of the templated gold nanodonut arrays enables good spectral tunability. Bulk refractive index sensing experiments show that a high SPR sensitivity of ∼758 nm per refractive index unit, which outperforms many plasmonic nanostructures fabricated by both top-down and bottom-up approaches, can be achieved using the templated gold nanodonut arrays. Numerical finite-difference time-domain simulations have also been performed to complement the optical characterization and the theoretical results match well with the experimental measurements. PMID:27040938

  6. Self-assembled periodic patterns on the optical fiber tip by microsphere arrays

    NASA Astrophysics Data System (ADS)

    Pisco, Marco; Galeotti, Francesco; Grisci, Giorgio; Quero, Giuseppe; Cusano, Andrea

    2015-09-01

    In this work, we report a fabrication route for self-assembling periodic patterns on optical fiber tips. The technique is based on self-assembling polystyrene microspheres at the air/water interface and on successive transferring of the monolayer colloidal crystal on the fiber tip. By applying to the fiber further treatments like particle size reduction, metal coating and sphere removal, different periodic structures are conveniently realized. The results obtained indicate that self-assembly technique affords opportunity to create on the optical fiber tip dielectric and metallic-dielectric spheres' arrays with a feature size down to a submicron scale or metallic patterns with a few hundred nanometers at low fabrication costs.

  7. Study of light extraction efficiency of flip-chip GaN-based LEDs with different periodic arrays

    NASA Astrophysics Data System (ADS)

    Chen, Xinlian; Kong, Fanmin; Li, Kang; Ding, Qingan; Zhang, Mingyu; Li, Wei

    2014-03-01

    To improve light extraction efficiency (LEE) of the GaN-based LEDs, it has become a practical technique to form 2D periodic micro/nanostructure arrays in an n- or p-GaN layer. However, the fabrication of micro/nanostructure arrays in the thinner p-GaN layer can deteriorate the electrical characteristics, sometimes even damage the QWs active region. In this study, numerical simulations based on the Monte Carlo ray tracing method were carried out to investigate the influence of the different periodic arrays in the thicker n-GaN layer on the LEE of the LEDs. To find the optimal structure, the study was divided into three parts. Firstly, the parametrical influence of the different periodic arrays on the LEE was numerically simulated. The results showed that micro-cone arrays can effectively enhance the LEE and the maximum LEE can be obtained as the bottom of each cone pattern was in contact with adjacent cones. Secondly, by comparing micro-cone arrays with micro-pyramid arrays, the micro-cone arrays were superior to micro-pyramid arrays in terms of enhancing LEE. Lastly, the truncated cone arrays and truncated cone hole arrays with different upper radius were studied. The results indicated that the truncated cone arrays in top radius of less than 0.4 µm showed a certain enhancement of the LEE and about 3 times LEE improvement was obtained as R=0.2μm and h=1.0μm, compared with the planar flip-chip LEDs. Our results will provide important theoretical implications in development of high-power and high-brightness LEDs.

  8. The importance of 3D dosimetry

    NASA Astrophysics Data System (ADS)

    Low, Daniel

    2015-01-01

    Radiation therapy has been getting progressively more complex for the past 20 years. Early radiation therapy techniques needed only basic dosimetry equipment; motorized water phantoms, ionization chambers, and basic radiographic film techniques. As intensity modulated radiation therapy and image guided therapy came into widespread practice, medical physicists were challenged with developing effective and efficient dose measurement techniques. The complex 3-dimensional (3D) nature of the dose distributions that were being delivered demanded the development of more quantitative and more thorough methods for dose measurement. The quality assurance vendors developed a wide array of multidetector arrays that have been enormously useful for measuring and characterizing dose distributions, and these have been made especially useful with the advent of 3D dose calculation systems based on the array measurements, as well as measurements made using film and portal imagers. Other vendors have been providing 3D calculations based on data from the linear accelerator or the record and verify system, providing thorough evaluation of the dose but lacking quality assurance (QA) of the dose delivery process, including machine calibration. The current state of 3D dosimetry is one of a state of flux. The vendors and professional associations are trying to determine the optimal balance between thorough QA, labor efficiency, and quantitation. This balance will take some time to reach, but a necessary component will be the 3D measurement and independent calculation of delivered radiation therapy dose distributions.

  9. Flow through a cylindrical pipe with a periodic array of fractal orifices

    NASA Astrophysics Data System (ADS)

    van Melick, P. A. J.; Geurts, B. J.

    2013-12-01

    We apply direct numerical simulation (DNS) of the incompressible Navier-Stokes equations to predict flow through a cylindrical pipe in which a periodic array of orifice plates with a fractal perimeter is mounted. The flow is simulated using a volume penalization immersed boundary method with which the geometric complexity of the orifice plate is represented. Adding a periodic array of orifice plates to a cylindrical pipe is shown to increase the mixing efficiency of the flow in the laminar regime. The average stretching rate is shown to increase by a factor of up to 5, comparing pipe flow without orifice plates to flow passing through an orifice plate derived from the Koch snowflake fractal. The dispersion rate is shown to increase by a factor of up to 4. In laminar flow, the viscous forces are most important close to the walls, causing orifice geometries with the largest perimeter to exhibit the largest axial velocities near the centerline of the pipe and the largest pressure drop to maintain the prescribed volumetric flow rate. The immersed boundary method is also applied to turbulent flow through a ‘fractal-orifices pipe’ at Re = 4300. It is shown that the pressure drop that is required to maintain the specified volumetric flow rate decreases by about 15% on comparing orifice plates with a circular opening to orifice plates with more complex shapes that contain several corners such as triangles, squares, stars and the Koch snowflake.

  10. 3D microscope

    NASA Astrophysics Data System (ADS)

    Iizuka, Keigo

    2008-02-01

    In order to circumvent the fact that only one observer can view the image from a stereoscopic microscope, an attachment was devised for displaying the 3D microscopic image on a large LCD monitor for viewing by multiple observers in real time. The principle of operation, design, fabrication, and performance are presented, along with tolerance measurements relating to the properties of the cellophane half-wave plate used in the design.

  11. 3D Ion Temperature Reconstruction

    NASA Astrophysics Data System (ADS)

    Tanabe, Hiroshi; You, Setthivoine; Balandin, Alexander; Inomoto, Michiaki; Ono, Yasushi

    2009-11-01

    The TS-4 experiment at the University of Tokyo collides two spheromaks to form a single high-beta compact toroid. Magnetic reconnection during the merging process heats and accelerates the plasma in toroidal and poloidal directions. The reconnection region has a complex 3D topology determined by the pitch of the spheromak magnetic fields at the merging plane. A pair of multichord passive spectroscopic diagnostics have been established to measure the ion temperature and velocity in the reconnection volume. One setup measures spectral lines across a poloidal plane, retrieving velocity and temperature from Abel inversion. The other, novel setup records spectral lines across another section of the plasma and reconstructs velocity and temperature from 3D vector and 2D scalar tomography techniques. The magnetic field linking both measurement planes is determined from in situ magnetic probe arrays. The ion temperature is then estimated within the volume between the two measurement planes and at the reconnection region. The measurement is followed over several repeatable discharges to follow the heating and acceleration process during the merging reconnection.

  12. Fabrication of large periodic arrays of AlGaAs microdisks by laser-interference lithography and selective etching

    NASA Astrophysics Data System (ADS)

    Petter, K.; Kipp, T.; Heyn, Ch.; Heitmann, D.; Schuller, C.

    2002-07-01

    By laser-interference lithography, reactive-ion etching, and selective wet-chemical etching using a citric acid-based solution, we have fabricated large periodic arrays of AlGaAs microdisks with periods of 4 mum and disk diameters between 1.5 and 2 mum. The arrays are characterized by temperature-dependent photoluminescence spectroscopy. Taking into account the below-threshold absorption of the quantum wells inside the disks, we get disk quality factors close to the theoretical maximum value. We demonstrate that our technique allows one also to produce one-dimensionally or two-dimensionally coupled arrays of microdisks.

  13. Maintenance of a bone collagen phenotype by osteoblast-like cells in 3D periodic porous titanium (Ti-6Al-4 V) structures fabricated by selective electron beam melting

    PubMed Central

    Hrabe, Nikolas W.; Heinl, Peter; Bordia, Rajendra K.; Körner, Carolin; Fernandes, Russell J.

    2013-01-01

    Regular 3D periodic porous Ti-6Al-4 V structures were fabricated by the selective electron beam melting method (EBM) over a range of relative densities (0.17–0.40) and pore sizes (500–1500 μm). Structures were seeded with human osteoblast-like cells (SAOS-2) and cultured for four weeks. Cells multiplied within these structures and extracellular matrix collagen content increased. Type I and type V collagens typically synthesized by osteoblasts were deposited in the newly formed matrix with time in culture. High magnification scanning electron microscopy revealed cells attached to surfaces on the interior of the structures with an increasingly fibrous matrix. The in-vitro results demonstrate that the novel EBM-processed porous structures, designed to address the effect of stress-shielding, are conducive to osteoblast attachment, proliferation and deposition of a collagenous matrix characteristic of bone. PMID:23869614

  14. 3D vertical nanostructures for enhanced infrared plasmonics.

    PubMed

    Malerba, Mario; Alabastri, Alessandro; Miele, Ermanno; Zilio, Pierfrancesco; Patrini, Maddalena; Bajoni, Daniele; Messina, Gabriele C; Dipalo, Michele; Toma, Andrea; Proietti Zaccaria, Remo; De Angelis, Francesco

    2015-01-01

    The exploitation of surface plasmon polaritons has been mostly limited to the visible and near infrared range, due to the low frequency limit for coherent plasmon excitation and the reduction of confinement on the metal surface for lower energies. In this work we show that 3D--out of plane--nanostructures can considerably increase the intrinsic quality of the optical output, light confinement and electric field enhancement factors, also in the near and mid-infrared. We suggest that the physical principle relies on the combination of far field and near field interactions between neighboring antennas, promoted by the 3D out-of-plane geometry. We first analyze the changes in the optical behavior, which occur when passing from a single on-plane nanostructure to a 3D out-of-plane configuration. Then we show that by arranging the nanostructures in periodic arrays, 3D architectures can provide, in the mid-IR, a much stronger plasmonic response, compared to that achievable with the use of 2D configurations, leading to higher energy harvesting properties and improved Q-factors, with bright perspective up to the terahertz range. PMID:26552340

  15. 3D vertical nanostructures for enhanced infrared plasmonics

    PubMed Central

    Malerba, Mario; Alabastri, Alessandro; Miele, Ermanno; Zilio, Pierfrancesco; Patrini, Maddalena; Bajoni, Daniele; Messina, Gabriele C.; Dipalo, Michele; Toma, Andrea; Proietti Zaccaria, Remo; De Angelis, Francesco

    2015-01-01

    The exploitation of surface plasmon polaritons has been mostly limited to the visible and near infrared range, due to the low frequency limit for coherent plasmon excitation and the reduction of confinement on the metal surface for lower energies. In this work we show that 3D - out of plane - nanostructures can considerably increase the intrinsic quality of the optical output, light confinement and electric field enhancement factors, also in the near and mid-infrared. We suggest that the physical principle relies on the combination of far field and near field interactions between neighboring antennas, promoted by the 3D out-of-plane geometry. We first analyze the changes in the optical behavior, which occur when passing from a single on-plane nanostructure to a 3D out-of-plane configuration. Then we show that by arranging the nanostructures in periodic arrays, 3D architectures can provide, in the mid-IR, a much stronger plasmonic response, compared to that achievable with the use of 2D configurations, leading to higher energy harvesting properties and improved Q-factors, with bright perspective up to the terahertz range. PMID:26552340

  16. Multiviewer 3D monitor

    NASA Astrophysics Data System (ADS)

    Kostrzewski, Andrew A.; Aye, Tin M.; Kim, Dai Hyun; Esterkin, Vladimir; Savant, Gajendra D.

    1998-09-01

    Physical Optics Corporation has developed an advanced 3-D virtual reality system for use with simulation tools for training technical and military personnel. This system avoids such drawbacks of other virtual reality (VR) systems as eye fatigue, headaches, and alignment for each viewer, all of which are due to the need to wear special VR goggles. The new system is based on direct viewing of an interactive environment. This innovative holographic multiplexed screen technology makes it unnecessary for the viewer to wear special goggles.

  17. 3D Audio System

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Ames Research Center research into virtual reality led to the development of the Convolvotron, a high speed digital audio processing system that delivers three-dimensional sound over headphones. It consists of a two-card set designed for use with a personal computer. The Convolvotron's primary application is presentation of 3D audio signals over headphones. Four independent sound sources are filtered with large time-varying filters that compensate for motion. The perceived location of the sound remains constant. Possible applications are in air traffic control towers or airplane cockpits, hearing and perception research and virtual reality development.

  18. Periodic shunted arrays for the control of noise radiation in an enclosure

    NASA Astrophysics Data System (ADS)

    Casadei, Filippo; Dozio, Lorenzo; Ruzzene, Massimo; Cunefare, Kenneth A.

    2010-08-01

    This work presents numerical and experimental investigations of the application of a periodic array of resistive-inductive (RL) shunted piezoelectric patches for the attenuation of broadband noise radiated by a flexible plate in an enclosed cavity. A 4×4 lay-out of piezoelectric patches is bonded to the surface of a rectangular plate fully clamped to the top face of a rectangular cavity. Each piezo-patch is shunted through a single RL circuit, and all shunting circuits are tuned at the same frequency. The response of the resulting periodic structure is characterized by frequency bandgaps where vibrations and associated noise are strongly attenuated. The location and extent of induced bandgaps are predicted by the application of Bloch theorem on a unit cell of the periodic assembly, and they are controlled by proper selection of the shunting circuit impedance. A coupled piezo-structural-acoustic finite element model is developed to evaluate the noise reduction performance. Strong attenuation of multiple panel-controlled modes is observed over broad frequency bands. The proposed concept is tested on an aluminum plate mounted in a wooden box and driven by a shaker. Experimental results are presented in terms of pressure responses recorded using a grid of microphones placed inside the acoustic box.

  19. 3D Surgical Simulation

    PubMed Central

    Cevidanes, Lucia; Tucker, Scott; Styner, Martin; Kim, Hyungmin; Chapuis, Jonas; Reyes, Mauricio; Proffit, William; Turvey, Timothy; Jaskolka, Michael

    2009-01-01

    This paper discusses the development of methods for computer-aided jaw surgery. Computer-aided jaw surgery allows us to incorporate the high level of precision necessary for transferring virtual plans into the operating room. We also present a complete computer-aided surgery (CAS) system developed in close collaboration with surgeons. Surgery planning and simulation include construction of 3D surface models from Cone-beam CT (CBCT), dynamic cephalometry, semi-automatic mirroring, interactive cutting of bone and bony segment repositioning. A virtual setup can be used to manufacture positioning splints for intra-operative guidance. The system provides further intra-operative assistance with the help of a computer display showing jaw positions and 3D positioning guides updated in real-time during the surgical procedure. The CAS system aids in dealing with complex cases with benefits for the patient, with surgical practice, and for orthodontic finishing. Advanced software tools for diagnosis and treatment planning allow preparation of detailed operative plans, osteotomy repositioning, bone reconstructions, surgical resident training and assessing the difficulties of the surgical procedures prior to the surgery. CAS has the potential to make the elaboration of the surgical plan a more flexible process, increase the level of detail and accuracy of the plan, yield higher operative precision and control, and enhance documentation of cases. Supported by NIDCR DE017727, and DE018962 PMID:20816308

  20. Wideband analytical equivalent circuit for one-dimensional periodic stacked arrays.

    PubMed

    Molero, Carlos; Rodríguez-Berral, Raúl; Mesa, Francisco; Medina, Francisco; Yakovlev, Alexander B

    2016-01-01

    A wideband equivalent circuit is proposed for the accurate analysis of scattering from a set of stacked slit gratings illuminated by a plane wave with transverse magnetic or electric polarization that impinges normally or obliquely along one of the principal planes of the structure. The slit gratings are printed on dielectric slabs of arbitrary thickness, including the case of closely spaced gratings that interact by higher-order modes. A Π-circuit topology is obtained for a pair of coupled arrays, with fully analytical expressions for all the circuit elements. This equivalent Π circuit is employed as the basis to derive the equivalent circuit of finite stacks with any given number of gratings. Analytical expressions for the Brillouin diagram and the Bloch impedance are also obtained for infinite periodic stacks. PMID:26871189

  1. Wave propagation in beams with periodic arrays of airfoil-shaped resonating units

    NASA Astrophysics Data System (ADS)

    Casadei, Filippo; Bertoldi, Katia

    2014-12-01

    This paper presents an analytical and numerical study on the dispersion properties of an Euler-Bernoulli beam immersed in a steady fluid flow with periodic arrays of airfoil-shaped vibration absorbers attached to it. The resonance characteristics of the airfoils generate strong attenuation of flexural waves in the beam occurring at frequencies defined by the properties of the airfoils and the speed of the incident fluid. Analytical and numerical tools are developed to investigate the effects of the incident flow on the dispersion properties and the bandgaps of the system. Both steady and unsteady aerodynamic models are used to model the lift force and the pitching moment acting on the resonators and their effect on the dispersion relations of the system is evaluated. Finally, an effective medium description of the beam is developed to capture its behavior at long-wavelengths. In this regime, the system can be effectively considered as an acoustic metamaterial with adaptive dispersion properties.

  2. Sonic Stop-Bands for Periodic Arrays of Metallic Rods: Honeycomb Structure

    NASA Astrophysics Data System (ADS)

    Kushwaha, M. S.; Djafari-Rouhani, B.

    1998-12-01

    Extensive band structures have been computed for periodic arrays (in the honeycomb structure) of rigid metallic rods in air. Multiple complete acoustic stop bands have been obtained within which sound and vibrations are forbidden. These gaps start opening up for a filling fractionf≥8% and tend to increase with the filling fraction, exhibiting a maximum at the close-packing. A tandem structure has also been proposed that allows an ultrawideband filter for environmental or industrial noise to be achieved in the desired frequency range. This work is motivated by the recent experimental observation of sound attenuation on the sculpture by Eusebio Sempere, exhibited at the Juian March Foundation in Madrid [21] and complements the corresponding theoretical work [22, 23].

  3. Periodic molybdenum disc array for light trapping in amorphous silicon layer

    NASA Astrophysics Data System (ADS)

    Wang, Jiwei; Yang, Kang; Chen, Haiyan; Deng, Changkai; Li, Dongdong; Chen, Xiaoyuan; Ren, Wei

    2016-05-01

    We demonstrate the light trapping effect in amorphous silicon (a-Si:H) layer by inserting a layer of periodic molybdenum disc array (MDA) between the a-Si:H layer and the quartz substrate, which forms a three-layer structure of Si/MDA/SiO2. The MDA layer was fabricated by a new cost-effective method based on nano-imprint technology. Further light absorption enhancement was realized through altering the topography of MDA by annealing it at 700°C. The mechanism of light absorption enhancement in a-Si:H interfaced with MDA was analyzed, and the electric field distribution and light absorption curve of the different layers in the Si/MDA structure under light illumination of different wavelengths were simulated by employing numerical finite difference time domain (FDTD) solutions.

  4. All-dielectric periodic terajet waveguide using an array of coupled cuboids

    SciTech Connect

    Minin, I. V. Minin, O. V.; Pacheco-Peña, V. Beruete, M.

    2015-06-22

    In this paper, the recently proposed technique to produce photonic jets (terajets at terahertz (THz) frequencies) using 3D dielectric cuboids is applied in the design of a mesoscale cuboid-chain waveguide. The chains are basically designed with several dielectric cubes with side λ{sub 0} placed periodically along the axial z-axis and separated by an air-gap. Based on this, a systematic study of the focusing properties and wave guiding of this chain is performed when the air-gap between the dielectric cubes is changed from 0.25λ{sub 0} to 3λ{sub 0} with the best performance achieved at 2.5λ{sub 0}. An analysis when losses are included in the cubes is also done, demonstrating a robust performance. Finally, the wave guiding is experimentally demonstrated at sub-THz frequencies with a good agreement with numerical results. The simulation results of focusing and transport properties are carried out using Finite Integration Technique. The results here presented may be scaled to any frequency ranges such as millimeter, sub-millimeter, and optical frequencies.

  5. 3D Spray Droplet Distributions in Sneezes

    NASA Astrophysics Data System (ADS)

    Techet, Alexandra; Scharfman, Barry; Bourouiba, Lydia

    2015-11-01

    3D spray droplet clouds generated during human sneezing are investigated using the Synthetic Aperture Feature Extraction (SAFE) method, which relies on light field imaging (LFI) and synthetic aperture (SA) refocusing computational photographic techniques. An array of nine high-speed cameras are used to image sneeze droplets and tracked the droplets in 3D space and time (3D + T). An additional high-speed camera is utilized to track the motion of the head during sneezing. In the SAFE method, the raw images recorded by each camera in the array are preprocessed and binarized, simplifying post processing after image refocusing and enabling the extraction of feature sizes and positions in 3D + T. These binary images are refocused using either additive or multiplicative methods, combined with thresholding. Sneeze droplet centroids, radii, distributions and trajectories are determined and compared with existing data. The reconstructed 3D droplet centroids and radii enable a more complete understanding of the physical extent and fluid dynamics of sneeze ejecta. These measurements are important for understanding the infectious disease transmission potential of sneezes in various indoor environments.

  6. 3D Seismic Reflection Experiment over the Galicia Deep Basin

    NASA Astrophysics Data System (ADS)

    Sawyer, D. S.; Jordan, B.; Reston, T. J.; Minshull, T. A.; Klaeschen, D.; Ranero, C.; Shillington, D. J.; Morgan, J. K.

    2014-12-01

    In June thru September, 2013, a 3D reflection and a long offset seismic experiment were conducted at the Galicia rifted margin by investigators from the US, UK, Germany, and Spain. The 3D multichannel experiment covered 64 km by 20 km (1280 km2), using the RV Marcus Langseth. Four streamers 6 km long were deployed at 12.5 m hydrophone channel spacing. The streamers were 200 m apart. Two airgun arrays, each 3300 cu in, were fired alternately every 37.5 m, to collectively yield a 400 m wide sail line consisting of 8 CMP lines at 50 m spacing. The long offset seismic experiment included 72 short period OBS's deployed below the 3D reflection survey box. Most of the instruments recorded all the shots from the airgun array shots. The 3D seismic box covered a variety of geologic features. The Peridotite Ridge (PR), is associated with the exhumation of upper mantle rocks to the seafloor during the final stage of the continental separation between the Galicia Bank and the Grand Banks of Newfoundland. The S reflector is present below most of the continental blocks under the deep Galicia basin. S is interpreted to be a low-angle detachment fault formed late in the rifting process, and a number of rotated fault block basins and ranges containing pre and syn-rift sediments. Initial observations from stacked 3D seismic data, and samples of 2D pre-stack time migrated (PSTM) 3D seismic data show that the PR is elevated above the present seafloor in the South and not exposed through the seafloor in the North. The relative smoothness of the PR surface for the entire 20 km N-S contrasts with the more complex, shorter wavelength, faulting of the continental crustal blocks to the east. The PR does not seem to show offsets or any apparent internal structure. The PSTM dip lines show substantial improvement for the structures in the deep sedimentary basin East of the PR. These seem to extend the S reflector somewhat farther to the West. The migrated data show a substantial network of

  7. 3D polarimetric purity

    NASA Astrophysics Data System (ADS)

    Gil, José J.; San José, Ignacio

    2010-11-01

    From our previous definition of the indices of polarimetric purity for 3D light beams [J.J. Gil, J.M. Correas, P.A. Melero and C. Ferreira, Monogr. Semin. Mat. G. de Galdeano 31, 161 (2004)], an analysis of their geometric and physical interpretation is presented. It is found that, in agreement with previous results, the first parameter is a measure of the degree of polarization, whereas the second parameter (called the degree of directionality) is a measure of the mean angular aperture of the direction of propagation of the corresponding light beam. This pair of invariant, non-dimensional, indices of polarimetric purity contains complete information about the polarimetric purity of a light beam. The overall degree of polarimetric purity is obtained as a weighted quadratic average of the degree of polarization and the degree of directionality.

  8. 3D field harmonics

    SciTech Connect

    Caspi, S.; Helm, M.; Laslett, L.J.

    1991-03-30

    We have developed an harmonic representation for the three dimensional field components within the windings of accelerator magnets. The form by which the field is presented is suitable for interfacing with other codes that make use of the 3D field components (particle tracking and stability). The field components can be calculated with high precision and reduced cup time at any location (r,{theta},z) inside the magnet bore. The same conductor geometry which is used to simulate line currents is also used in CAD with modifications more readily available. It is our hope that the format used here for magnetic fields can be used not only as a means of delivering fields but also as a way by which beam dynamics can suggest correction to the conductor geometry. 5 refs., 70 figs.

  9. 'Bonneville' in 3-D!

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The Mars Exploration Rover Spirit took this 3-D navigation camera mosaic of the crater called 'Bonneville' after driving approximately 13 meters (42.7 feet) to get a better vantage point. Spirit's current position is close enough to the edge to see the interior of the crater, but high enough and far enough back to get a view of all of the walls. Because scientists and rover controllers are so pleased with this location, they will stay here for at least two more martian days, or sols, to take high resolution panoramic camera images of 'Bonneville' in its entirety. Just above the far crater rim, on the left side, is the rover's heatshield, which is visible as a tiny reflective speck.

  10. Displacement field of doubly periodic array of dislocation dipoles in elastically anisotropic media

    NASA Astrophysics Data System (ADS)

    Soleymani Shishvan, Siamak; Moghaddam, Babak

    2016-01-01

    The displacement field for dislocation dipoles periodically arranged along both x- and y-directions is found to be conditionally convergent. That is, different displacement fields are obtained depending on the order of the summation to be adopted. From the two summations, one can be performed analytically; however, the other one has to be performed numerically. We first derive analytic expressions for the displacement field of periodic array of dipoles along one (either x or y) direction considering anisotropic elasticity; they are then applied for the numerical summation (practically truncated) along the other direction. The resulting displacement field needs to be corrected by subtracting the spurious displacement field, whose expressions are analytically derived. As a first application, we employ the displacement and corresponding stress fields in a 2D discrete dislocation plasticity (DDP) model of a fine-grained polycrystal under shear loading. To this end, anisotropic plane-strain DDP method is utilised to solve the underlying boundary value problem. Subsequently, predictions of size-dependent plastic behaviour in anisotropic polycrystals with grain sizes in the range ? are presented.

  11. Periodic arrays of metal nanorings and nanocrescents fabricated by a scalable colloidal templating approach.

    PubMed

    Liu, Xuefeng; Choi, Baeck; Gozubenli, Numan; Jiang, Peng

    2013-11-01

    Here, we report a scalable bottom-up approach for fabricating periodic arrays of metal nanorings and nanocrescents. Wafer-scale monolayer silica colloidal crystals with an unusual non-close-packed structure prepared by a simple and rapid spin-coating technology are used as both etching and shadowing masks to create nanoring-shaped trenches in between templated polymer posts and sacrificial nanoholes. Directional deposition of metals in the trenches followed by liftoff of the polymer posts and the sacrificial nanoholes results in forming ordered metal nanorings. The inner and outer radii of the final nanorings are determined by the sizes of the templated polymer posts and the silica microspheres which can be easily adjusted by tuning the spin-coating and templating conditions. Most importantly, by simply controlling the tilt angle of the substrate toward the directional metal beams, continuous geometric transition from concentric nanorings to eccentric nanorings to nanocrescents can be achieved. This new colloidal templating approach is compatible with standard semiconductor microfabrication, promising for mass-production and on-chip integration of periodic nanorings and nanocrescents for a wide spectrum of technological applications ranging from nanooptical devices and ultrasensitive biosensing to magnetic memories and logic circuits. PMID:23978286

  12. Light field display and 3D image reconstruction

    NASA Astrophysics Data System (ADS)

    Iwane, Toru

    2016-06-01

    Light field optics and its applications become rather popular in these days. With light field optics or light field thesis, real 3D space can be described in 2D plane as 4D data, which we call as light field data. This process can be divided in two procedures. First, real3D scene is optically reduced with imaging lens. Second, this optically reduced 3D image is encoded into light field data. In later procedure we can say that 3D information is encoded onto a plane as 2D data by lens array plate. This transformation is reversible and acquired light field data can be decoded again into 3D image with the arrayed lens plate. "Refocusing" (focusing image on your favorite point after taking a picture), light-field camera's most popular function, is some kind of sectioning process from encoded 3D data (light field data) to 2D image. In this paper at first I show our actual light field camera and our 3D display using acquired and computer-simulated light field data, on which real 3D image is reconstructed. In second I explain our data processing method whose arithmetic operation is performed not in Fourier domain but in real domain. Then our 3D display system is characterized by a few features; reconstructed image is of finer resolutions than density of arrayed lenses and it is not necessary to adjust lens array plate to flat display on which light field data is displayed.

  13. 3D palmprint data fast acquisition and recognition

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoxu; Huang, Shujun; Gao, Nan; Zhang, Zonghua

    2014-11-01

    This paper presents a fast 3D (Three-Dimension) palmprint capturing system and develops an efficient 3D palmprint feature extraction and recognition method. In order to fast acquire accurate 3D shape and texture of palmprint, a DLP projector triggers a CCD camera to realize synchronization. By generating and projecting green fringe pattern images onto the measured palm surface, 3D palmprint data are calculated from the fringe pattern images. The periodic feature vector can be derived from the calculated 3D palmprint data, so undistorted 3D biometrics is obtained. Using the obtained 3D palmprint data, feature matching test have been carried out by Gabor filter, competition rules and the mean curvature. Experimental results on capturing 3D palmprint show that the proposed acquisition method can fast get 3D shape information of palmprint. Some initial experiments on recognition show the proposed method is efficient by using 3D palmprint data.

  14. Recent development of 3D display technology for new market

    NASA Astrophysics Data System (ADS)

    Kim, Sung-Sik

    2003-11-01

    A multi-view 3D video processor was designed and implemented with several FPGAs for real-time applications and a projection-type 3D display was introduced for low-cost commercialization. One high resolution projection panel and only one projection lens is capable of displaying multiview autostereoscopic images. It can cope with various arrangements of 3D camera systems (or pixel arrays) and resolutions of 3D displays. This system shows high 3-D image quality in terms of resolution, brightness, and contrast so it is well suited for the commercialization in the field of game and advertisement market.

  15. Prominent rocks - 3D

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Many prominent rocks near the Sagan Memorial Station are featured in this image, taken in stereo by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. Wedge is at lower left; Shark, Half-Dome, and Pumpkin are at center. Flat Top, about four inches high, is at lower right. The horizon in the distance is one to two kilometers away.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  16. 'Diamond' in 3-D

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This 3-D, microscopic imager mosaic of a target area on a rock called 'Diamond Jenness' was taken after NASA's Mars Exploration Rover Opportunity ground into the surface with its rock abrasion tool for a second time.

    Opportunity has bored nearly a dozen holes into the inner walls of 'Endurance Crater.' On sols 177 and 178 (July 23 and July 24, 2004), the rover worked double-duty on Diamond Jenness. Surface debris and the bumpy shape of the rock resulted in a shallow and irregular hole, only about 2 millimeters (0.08 inch) deep. The final depth was not enough to remove all the bumps and leave a neat hole with a smooth floor. This extremely shallow depression was then examined by the rover's alpha particle X-ray spectrometer.

    On Sol 178, Opportunity's 'robotic rodent' dined on Diamond Jenness once again, grinding almost an additional 5 millimeters (about 0.2 inch). The rover then applied its Moessbauer spectrometer to the deepened hole. This double dose of Diamond Jenness enabled the science team to examine the rock at varying layers. Results from those grindings are currently being analyzed.

    The image mosaic is about 6 centimeters (2.4 inches) across.

  17. A pseudo-3D approach based on electron backscatter diffraction and backscatter electron imaging to study the character of phase boundaries between Mg and long period stacking ordered phase in a Mg–2Y–Zn alloy

    SciTech Connect

    Afshar, Mehran Zaefferer, Stefan

    2015-03-15

    In Mg–2 at.% Y–1 at.% Zn alloys, the LPSO (Long Period Stacking Ordered) phase is important to improve mechanical properties of the material. The aim of this paper is to present a study on the phase boundary character in these two-phase alloys. Using EBSD pattern analysis it was found that the 24R structure is the dominant LPSO phase structure in the current alloy. The phase boundary character between the Mg matrix and the LPSO phase was investigated using an improved pseudo-3D EBSD (electron backscatter diffraction) technique in combination with BSE or SE (backscatter or secondary electron) imaging. A large amount of very low-angle phase boundaries was detected. The (0 0 0 2) plane in the Mg matrix which is parallel to the (0 0 0 24) plane in the LPSO phase was found to be the most frequent plane for these phase boundaries. This plane is supposed to be the habit plane of the eutectic co-solidification of the Mg matrix and the LPSO phase. - Highlights: • It is shown that for the investigated alloy the LPSO phase has mainly 24R crystal structure. • A new method is presented which allows accurate determination of the 5-parameter grain or phase boundary character. • It is found that the low-angle phase boundaries appearing in the alloy all have basal phase boundary planes.

  18. Faint object 3D spectroscopy with PMAS

    NASA Astrophysics Data System (ADS)

    Roth, Martin M.; Becker, Thomas; Kelz, Andreas; Bohm, Petra

    2004-09-01

    PMAS is a fiber-coupled lens array type of integral field spectrograph, which was commissioned at the Calar Alto 3.5m Telescope in May 2001. The optical layout of the instrument was chosen such as to provide a large wavelength coverage, and good transmission from 0.35 to 1 μm. One of the major objectives of the PMAS development has been to perform 3D spectrophotometry, taking advantage of the contiguous array of spatial elements over the 2-dimensional field-of-view of the integral field unit. With science results obtained during the first two years of operation, we illustrate that 3D spectroscopy is an ideal tool for faint object spectrophotometry.

  19. 3D IC for Future HEP Detectors

    SciTech Connect

    Thom, J.; Lipton, R.; Heintz, U.; Johnson, M.; Narain, M.; Badman, R.; Spiegel, L.; Triphati, M.; Deptuch, G.; Kenney, C.; Parker, S.; Ye, Z.; Siddons, D.

    2014-11-07

    Three dimensional integrated circuit technologies offer the possibility of fabricating large area arrays of sensors integrated with complex electronics with minimal dead area, which makes them ideally suited for applications at the LHC upgraded detectors and other future detectors. Here we describe ongoing R&D efforts to demonstrate functionality of components of such detectors. This also includes the study of integrated 3D electronics with active edge sensors to produce "active tiles" which can be tested and assembled into arrays of arbitrary size with high yield.

  20. 3D IC for future HEP detectors

    NASA Astrophysics Data System (ADS)

    Thom, J.; Lipton, R.; Heintz, U.; Johnson, M.; Narain, M.; Badman, R.; Spiegel, L.; Triphati, M.; Deptuch, G.; Kenney, C.; Parker, S.; Ye, Z.; Siddons, D. P.

    2014-11-01

    Three dimensional integrated circuit technologies offer the possibility of fabricating large area arrays of sensors integrated with complex electronics with minimal dead area, which makes them ideally suited for applications at the LHC upgraded detectors and other future detectors. We describe ongoing R&D efforts to demonstrate functionality of components of such detectors. This includes the study of integrated 3D electronics with active edge sensors to produce "active tiles" which can be tested and assembled into arrays of arbitrary size with high yield.

  1. Enhanced photoemission from laser-excited plasmonic nano-objects in periodic arrays

    NASA Astrophysics Data System (ADS)

    Fedorov, N.; Geoffroy, G.; Duchateau, G.; Štolcová, L.; Proška, J.; Novotný, F.; Domonkos, M.; Jouin, H.; Martin, P.; Raynaud, M.

    2016-08-01

    The process of photoelectron emission from gold surfaces covered with nano-objects that are organized in the form of a periodic array is addressed in the short laser pulse regime (≤slant 50 fs) at moderate intensities ∼ {{10}10} W cm‑2 and for various laser wavelengths. The emission spectrum from a gold single crystal measured under the same conditions is used for reference. The comparison of the photo-emission yield and the energy of the ejected electrons with their counterparts from the (more simple) reference system shows that the periodic conditions imposed on the target surface drastically enhance both quantities. In addition to the standard mechanism of Coulomb explosion, a second mechanism comes into play, driven by surface plasmon excitation. This can be clearly demonstrated by varying the laser wavelength. This interpretation of the experimental data is supported by predictions from model calculations that account both for the primary quantum electron emission and for the subsequent surface-plasmon-driven acceleration in the vacuum. Despite the fact that the incident laser intensity is as low as ∼ 5× {{10}10} W cm‑2, such a structured target permits generating electrons with energies as high as 300 eV. Experiments with two incident laser beams of different wavelengths with an adjustable delay, have also been carried out. The results show that there exist various channels for the decay of the photo-emission signal, depending on the target type. These observations are shedding light on the various relaxation mechanisms that take place on different timescales.

  2. Enhanced photoemission from laser-excited plasmonic nano-objects in periodic arrays.

    PubMed

    Fedorov, N; Geoffroy, G; Duchateau, G; Štolcová, L; Proška, J; Novotný, F; Domonkos, M; Jouin, H; Martin, P; Raynaud, M

    2016-08-10

    The process of photoelectron emission from gold surfaces covered with nano-objects that are organized in the form of a periodic array is addressed in the short laser pulse regime ([Formula: see text] fs) at moderate intensities [Formula: see text] W cm(-2) and for various laser wavelengths. The emission spectrum from a gold single crystal measured under the same conditions is used for reference. The comparison of the photo-emission yield and the energy of the ejected electrons with their counterparts from the (more simple) reference system shows that the periodic conditions imposed on the target surface drastically enhance both quantities. In addition to the standard mechanism of Coulomb explosion, a second mechanism comes into play, driven by surface plasmon excitation. This can be clearly demonstrated by varying the laser wavelength. This interpretation of the experimental data is supported by predictions from model calculations that account both for the primary quantum electron emission and for the subsequent surface-plasmon-driven acceleration in the vacuum. Despite the fact that the incident laser intensity is as low as [Formula: see text] W cm(-2), such a structured target permits generating electrons with energies as high as 300 eV. Experiments with two incident laser beams of different wavelengths with an adjustable delay, have also been carried out. The results show that there exist various channels for the decay of the photo-emission signal, depending on the target type. These observations are shedding light on the various relaxation mechanisms that take place on different timescales. PMID:27299999

  3. Mechanism Leading to Formation of Periodic Nanopillar Arrays in Confined Ultrathin Polymer Films

    NASA Astrophysics Data System (ADS)

    Troian, Sandra; Dietzel, Mathias

    2008-11-01

    Previous groups have reported the spontaneous formation of periodic nanopillar arrays in ultrathin polymer films (order 100 nm in thickness) confined inbetween two flat smooth substrates and subject to an ultrahigh transverse thermal gradient (order 10^6-10^7 ^oK/cm). Crucial to these experiments is the presence of an overlying nanofilm of a second fluid to preserve a deformable interface at the polymer-fluid boundary. The formation of structures resembling stripes, columns or spirals has been attributed to a normal interfacial radiation pressure arising from phonon-like reflections at the interface separating media with different acoustic impedance. A linear stability analysis of a thin bilayer film within the lubrication approximation shows that tangential thermocapillary stresses at the free interface can well explain the phenomena observed. Predictions of the most unstable wavelength as a function of the plate spacing, thermal gradient, and material parameters provide a good fit to the experimental data. This instability can be classified as a long wavelength Bénard instability studied a decade ago by VanHook et al. The parameter range in current experiments, however, as characterized by the ratio of thermocapillary to capillary to gravitational forces, falls beyond the range studied previously.

  4. Multimodal vibration damping through a periodic array of piezoelectric patches connected to a passive network

    NASA Astrophysics Data System (ADS)

    Lossouarn, Boris; Aucejo, Mathieu; Deü, Jean-François

    2015-04-01

    In damping devices involving piezoelectric elements, a single piezoelectric patch cannot consistently achieve multimodal control because of charge cancellation or vibration node location. In order to sense and control structural vibration on a prescribed frequency range, a solution consists in using an array of several piezoelectric patches being small compared to the smallest wavelength to control. Then, as an extension of the tuned mass damper strategy, a passive multimodal control requires to implement a damping system whose modes are as close as possible to those of the controlled structure. In this way, the electrical equivalent of the discretized mechanical structure represents the passive network that optimizes the energy transfer between the two media. For one-dimensional structures, a periodic distribution in several unit cells enables the use of the transfer matrix method applied on electromechanical state-vectors. The optimal passive networks are obtained for the propagation of longitudinal and transverse waves and a numerical implementation of the coupled behavior is performed. Compared to the more classical resonant shunts, the network topology induces promising multimodal damping and a reduction of the needed inductance. It is thus possible to create a completely passive electrical structure as it is demonstrated experimentally by using only purely passive components.

  5. Formation of periodic interfacial misfit dislocation array at the InSb/GaAs interface via surface anion exchange

    NASA Astrophysics Data System (ADS)

    Jia, Bo Wen; Tan, Kian Hua; Loke, Wan Khai; Wicaksono, Satrio; Yoon, Soon Fatt

    2016-07-01

    The relationship between growth temperature and the formation of periodic interfacial misfit (IMF) dislocations via the anion exchange process in InSb/GaAs heteroepitaxy was systematically investigated. The microstructural and electrical properties of the epitaxial layer were characterized using atomic force microscope, high-resolution x-ray diffraction, transmission electron microscopy, and Hall resistance measurement. The formation of interfacial misfit (IMF) dislocation arrays depended on growth temperature. A uniformly distributed IMF array was found in a sample grown at 310 °C, which also exhibited the lowest threading dislocation density. The analysis suggested that an incomplete As-for-Sb anion exchange process impeded the formation of IMF on sample grown above 310 °C. At growth temperature below 310 °C, island coalescence led to the formation of 60° dislocations and the disruption of periodic IMF array. All samples showed higher electron mobility at 300 K than at 77 K.

  6. Full-color holographic 3D printer

    NASA Astrophysics Data System (ADS)

    Takano, Masami; Shigeta, Hiroaki; Nishihara, Takashi; Yamaguchi, Masahiro; Takahashi, Susumu; Ohyama, Nagaaki; Kobayashi, Akihiko; Iwata, Fujio

    2003-05-01

    A holographic 3D printer is a system that produces a direct hologram with full-parallax information using the 3-dimensional data of a subject from a computer. In this paper, we present a proposal for the reproduction of full-color images with the holographic 3D printer. In order to realize the 3-dimensional color image, we selected the 3 laser wavelength colors of red (λ=633nm), green (λ=533nm), and blue (λ=442nm), and we built a one-step optical system using a projection system and a liquid crystal display. The 3-dimensional color image is obtained by synthesizing in a 2D array the multiple exposure with these 3 wavelengths made on each 250mm elementary hologram, and moving recording medium on a x-y stage. For the natural color reproduction in the holographic 3D printer, we take the approach of the digital processing technique based on the color management technology. The matching between the input and output colors is performed by investigating first, the relation between the gray level transmittance of the LCD and the diffraction efficiency of the hologram and second, by measuring the color displayed by the hologram to establish a correlation. In our first experimental results a non-linear functional relation for single and multiple exposure of the three components were found. These results are the first step in the realization of a natural color 3D image produced by the holographic color 3D printer.

  7. Miniaturized 3D microscope imaging system

    NASA Astrophysics Data System (ADS)

    Lan, Yung-Sung; Chang, Chir-Weei; Sung, Hsin-Yueh; Wang, Yen-Chang; Chang, Cheng-Yi

    2015-05-01

    We designed and assembled a portable 3-D miniature microscopic image system with the size of 35x35x105 mm3 . By integrating a microlens array (MLA) into the optical train of a handheld microscope, the biological specimen's image will be captured for ease of use in a single shot. With the light field raw data and program, the focal plane can be changed digitally and the 3-D image can be reconstructed after the image was taken. To localize an object in a 3-D volume, an automated data analysis algorithm to precisely distinguish profundity position is needed. The ability to create focal stacks from a single image allows moving or specimens to be recorded. Applying light field microscope algorithm to these focal stacks, a set of cross sections will be produced, which can be visualized using 3-D rendering. Furthermore, we have developed a series of design rules in order to enhance the pixel using efficiency and reduce the crosstalk between each microlens for obtain good image quality. In this paper, we demonstrate a handheld light field microscope (HLFM) to distinguish two different color fluorescence particles separated by a cover glass in a 600um range, show its focal stacks, and 3-D position.

  8. Quasi 3D dosimetry (EPID, conventional 2D/3D detector matrices)

    NASA Astrophysics Data System (ADS)

    Bäck, A.

    2015-01-01

    Patient specific pretreatment measurement for IMRT and VMAT QA should preferably give information with a high resolution in 3D. The ability to distinguish complex treatment plans, i.e. treatment plans with a difference between measured and calculated dose distributions that exceeds a specified tolerance, puts high demands on the dosimetry system used for the pretreatment measurements and the results of the measurement evaluation needs a clinical interpretation. There are a number of commercial dosimetry systems designed for pretreatment IMRT QA measurements. 2D arrays such as MapCHECK® (Sun Nuclear), MatriXXEvolution (IBA Dosimetry) and OCTAVIOUS® 1500 (PTW), 3D phantoms such as OCTAVIUS® 4D (PTW), ArcCHECK® (Sun Nuclear) and Delta4 (ScandiDos) and software for EPID dosimetry and 3D reconstruction of the dose in the patient geometry such as EPIDoseTM (Sun Nuclear) and Dosimetry CheckTM (Math Resolutions) are available. None of those dosimetry systems can measure the 3D dose distribution with a high resolution (full 3D dose distribution). Those systems can be called quasi 3D dosimetry systems. To be able to estimate the delivered dose in full 3D the user is dependent on a calculation algorithm in the software of the dosimetry system. All the vendors of the dosimetry systems mentioned above provide calculation algorithms to reconstruct a full 3D dose in the patient geometry. This enables analyzes of the difference between measured and calculated dose distributions in DVHs of the structures of clinical interest which facilitates the clinical interpretation and is a promising tool to be used for pretreatment IMRT QA measurements. However, independent validation studies on the accuracy of those algorithms are scarce. Pretreatment IMRT QA using the quasi 3D dosimetry systems mentioned above rely on both measurement uncertainty and accuracy of calculation algorithms. In this article, these quasi 3D dosimetry systems and their use in patient specific pretreatment IMRT

  9. Computer numerical control (CNC) lithography: light-motion synchronized UV-LED lithography for 3D microfabrication

    NASA Astrophysics Data System (ADS)

    Kim, Jungkwun; Yoon, Yong-Kyu; Allen, Mark G.

    2016-03-01

    This paper presents a computer-numerical-controlled ultraviolet light-emitting diode (CNC UV-LED) lithography scheme for three-dimensional (3D) microfabrication. The CNC lithography scheme utilizes sequential multi-angled UV light exposures along with a synchronized switchable UV light source to create arbitrary 3D light traces, which are transferred into the photosensitive resist. The system comprises a switchable, movable UV-LED array as a light source, a motorized tilt-rotational sample holder, and a computer-control unit. System operation is such that the tilt-rotational sample holder moves in a pre-programmed routine, and the UV-LED is illuminated only at desired positions of the sample holder during the desired time period, enabling the formation of complex 3D microstructures. This facilitates easy fabrication of complex 3D structures, which otherwise would have required multiple manual exposure steps as in the previous multidirectional 3D UV lithography approach. Since it is batch processed, processing time is far less than that of the 3D printing approach at the expense of some reduction in the degree of achievable 3D structure complexity. In order to produce uniform light intensity from the arrayed LED light source, the UV-LED array stage has been kept rotating during exposure. UV-LED 3D fabrication capability was demonstrated through a plurality of complex structures such as V-shaped micropillars, micropanels, a micro-‘hi’ structure, a micro-‘cat’s claw,’ a micro-‘horn,’ a micro-‘calla lily,’ a micro-‘cowboy’s hat,’ and a micro-‘table napkin’ array.

  10. 3D Printed Programmable Release Capsules.

    PubMed

    Gupta, Maneesh K; Meng, Fanben; Johnson, Blake N; Kong, Yong Lin; Tian, Limei; Yeh, Yao-Wen; Masters, Nina; Singamaneni, Srikanth; McAlpine, Michael C

    2015-08-12

    The development of methods for achieving precise spatiotemporal control over chemical and biomolecular gradients could enable significant advances in areas such as synthetic tissue engineering, biotic-abiotic interfaces, and bionanotechnology. Living organisms guide tissue development through highly orchestrated gradients of biomolecules that direct cell growth, migration, and differentiation. While numerous methods have been developed to manipulate and implement biomolecular gradients, integrating gradients into multiplexed, three-dimensional (3D) matrices remains a critical challenge. Here we present a method to 3D print stimuli-responsive core/shell capsules for programmable release of multiplexed gradients within hydrogel matrices. These capsules are composed of an aqueous core, which can be formulated to maintain the activity of payload biomolecules, and a poly(lactic-co-glycolic) acid (PLGA, an FDA approved polymer) shell. Importantly, the shell can be loaded with plasmonic gold nanorods (AuNRs), which permits selective rupturing of the capsule when irradiated with a laser wavelength specifically determined by the lengths of the nanorods. This precise control over space, time, and selectivity allows for the ability to pattern 2D and 3D multiplexed arrays of enzyme-loaded capsules along with tunable laser-triggered rupture and release of active enzymes into a hydrogel ambient. The advantages of this 3D printing-based method include (1) highly monodisperse capsules, (2) efficient encapsulation of biomolecular payloads, (3) precise spatial patterning of capsule arrays, (4) "on the fly" programmable reconfiguration of gradients, and (5) versatility for incorporation in hierarchical architectures. Indeed, 3D printing of programmable release capsules may represent a powerful new tool to enable spatiotemporal control over biomolecular gradients. PMID:26042472

  11. 3D Printed Programmable Release Capsules

    PubMed Central

    Gupta, Maneesh K.; Meng, Fanben; Johnson, Blake N.; Kong, Yong Lin; Tian, Limei; Yeh, Yao-Wen; Masters, Nina; Singamaneni, Srikanth; McAlpine, Michael C.

    2015-01-01

    The development of methods for achieving precise spatiotemporal control over chemical and biomolecular gradients could enable significant advances in areas such as synthetic tissue engineering, biotic–abiotic interfaces, and bionanotechnology. Living organisms guide tissue development through highly orchestrated gradients of biomolecules that direct cell growth, migration, and differentiation. While numerous methods have been developed to manipulate and implement biomolecular gradients, integrating gradients into multiplexed, three-dimensional (3D) matrices remains a critical challenge. Here we present a method to 3D print stimuli-responsive core/shell capsules for programmable release of multiplexed gradients within hydrogel matrices. These capsules are composed of an aqueous core, which can be formulated to maintain the activity of payload biomolecules, and a poly(lactic-co-glycolic) acid (PLGA, an FDA approved polymer) shell. Importantly, the shell can be loaded with plasmonic gold nanorods (AuNRs), which permits selective rupturing of the capsule when irradiated with a laser wavelength specifically determined by the lengths of the nanorods. This precise control over space, time, and selectivity allows for the ability to pattern 2D and 3D multiplexed arrays of enzyme-loaded capsules along with tunable laser-triggered rupture and release of active enzymes into a hydrogel ambient. The advantages of this 3D printing-based method include (1) highly monodisperse capsules, (2) efficient encapsulation of biomolecular payloads, (3) precise spatial patterning of capsule arrays, (4) “on the fly” programmable reconfiguration of gradients, and (5) versatility for incorporation in hierarchical architectures. Indeed, 3D printing of programmable release capsules may represent a powerful new tool to enable spatiotemporal control over biomolecular gradients. PMID:26042472

  12. Collision rates for rare cell capture in periodic obstacle arrays strongly depend on density of cell suspension.

    PubMed

    Cimrák, I

    2016-11-01

    Recently, computational modelling has been successfully used for determination of collision rates for rare cell capture in periodic obstacle arrays. The models were based on particle advection simulations where the cells were advected according to velocity field computed from two dimensional Navier-Stokes equations. This approach may be used under the assumption of very dilute cell suspensions where no mutual cell collisions occur. We use the object-in-fluid framework to demonstrate that even with low cell-to-fluid ratio, the optimal geometry of the obstacle array significantly changes. We show computational simulations for ratios of 3.5, 6.9 and 10.4% determining the optimal geometry of the periodic obstacle arrays. It was already previously demonstrated that cells in periodic obstacle arrays follow trajectories in two modes: the colliding mode and the zig-zag mode. The colliding mode maximizes the cell-obstacle collision frequency. Our simulations reveal that for dilute suspensions and for suspensions with cell-to-fluid ratio 3.5%, there is a range of column shifts for which the cells follow colliding trajectories. However we showed, that for 6.9 and 10.4%, the cells never follow colliding trajectories. PMID:27023645

  13. Multizone Paper Platform for 3D Cell Cultures

    PubMed Central

    Derda, Ratmir; Hong, Estrella; Mwangi, Martin; Mammoto, Akiko; Ingber, Donald E.; Whitesides, George M.

    2011-01-01

    In vitro 3D culture is an important model for tissues in vivo. Cells in different locations of 3D tissues are physiologically different, because they are exposed to different concentrations of oxygen, nutrients, and signaling molecules, and to other environmental factors (temperature, mechanical stress, etc). The majority of high-throughput assays based on 3D cultures, however, can only detect the average behavior of cells in the whole 3D construct. Isolation of cells from specific regions of 3D cultures is possible, but relies on low-throughput techniques such as tissue sectioning and micromanipulation. Based on a procedure reported previously (“cells-in-gels-in-paper” or CiGiP), this paper describes a simple method for culture of arrays of thin planar sections of tissues, either alone or stacked to create more complex 3D tissue structures. This procedure starts with sheets of paper patterned with hydrophobic regions that form 96 hydrophilic zones. Serial spotting of cells suspended in extracellular matrix (ECM) gel onto the patterned paper creates an array of 200 micron-thick slabs of ECM gel (supported mechanically by cellulose fibers) containing cells. Stacking the sheets with zones aligned on top of one another assembles 96 3D multilayer constructs. De-stacking the layers of the 3D culture, by peeling apart the sheets of paper, “sections” all 96 cultures at once. It is, thus, simple to isolate 200-micron-thick cell-containing slabs from each 3D culture in the 96-zone array. Because the 3D cultures are assembled from multiple layers, the number of cells plated initially in each layer determines the spatial distribution of cells in the stacked 3D cultures. This capability made it possible to compare the growth of 3D tumor models of different spatial composition, and to examine the migration of cells in these structures. PMID:21573103

  14. 3D Seismic Reflection Experiment Over the Galicia Deep Basin

    NASA Astrophysics Data System (ADS)

    Sawyer, Dale; Jordan, Brian; Tesi Sanjurjo, Mari; Alexanian, Ara; Morgan, Julia; Shillington, Donna; Reston, Timothy; Minshull, Timothy; Klaeschen, Dirk; Ranero, César

    2014-05-01

    In June thru September, 2013, a 3D reflection and a long offset seismic experiment were conducted at the Galicia rifted margin by investigators from the US, UK, Germany, and Spain. The 3D multichannel experiment covered 64 km by 20 km (1280 km2), using the RV Marcus Langseth. Four streamers 6 km long were deployed at 12.5 m hydrophone channel spacing. The streamers were 200 m apart. Two airgun arrays, each 3300 cu in, were fired alternately every 37.5 m, to collectively yield a 400 m wide sail line consisting of 8 CMP lines at 50 m spacing. The long offset seismic experiment included 72 short period OBS's deployed below the 3D reflection survey box. Most of the instruments recorded all the shots from the airgun array shots. The 3D seismic box covered a variety of geologic features. The Peridotite Ridge (PR), is associated with the exhumation of upper mantle rocks to the seafloor during the final stage of the continental separation between the Galicia Bank and the Grand Banks of Newfoundland. The S reflector is present below most of the continental blocks under the deep Galicia basin. S is interpreted to be a low-angle detachment fault formed late in the rifting process, and a number of rotated fault block basins and ranges containing pre and syn-rift sediments. Initial observations from stacked, but not yet migrated, 3D seismic data show that the PR is elevated above the present seafloor in the South and not exposed through the seafloor in the North. The relative smoothness of the PR surface for the entire 20 km N-S contrasts with the more complex, shorter wavelength, faulting of the continental crustal blocks to the east. The PR does not seem to show offsets or any apparent internal structure. However, migration will be required to see internal structure of the PR. Between the PR and the western most rifted continental crustal blocks, is a sedimentary basin about as wide as the PR and very different from the sedimentary basins bounded by the continental crustal

  15. 3D Spectroscopy in Astronomy

    NASA Astrophysics Data System (ADS)

    Mediavilla, Evencio; Arribas, Santiago; Roth, Martin; Cepa-Nogué, Jordi; Sánchez, Francisco

    2011-09-01

    Preface; Acknowledgements; 1. Introductory review and technical approaches Martin M. Roth; 2. Observational procedures and data reduction James E. H. Turner; 3. 3D Spectroscopy instrumentation M. A. Bershady; 4. Analysis of 3D data Pierre Ferruit; 5. Science motivation for IFS and galactic studies F. Eisenhauer; 6. Extragalactic studies and future IFS science Luis Colina; 7. Tutorials: how to handle 3D spectroscopy data Sebastian F. Sánchez, Begona García-Lorenzo and Arlette Pécontal-Rousset.

  16. 3D Elevation Program—Virtual USA in 3D

    USGS Publications Warehouse

    Lukas, Vicki; Stoker, J.M.

    2016-01-01

    The U.S. Geological Survey (USGS) 3D Elevation Program (3DEP) uses a laser system called ‘lidar’ (light detection and ranging) to create a virtual reality map of the Nation that is very accurate. 3D maps have many uses with new uses being discovered all the time.  

  17. Dynamic templating: a large area processing route for the assembly of periodic arrays of sub-micrometer and nanoscale structures

    NASA Astrophysics Data System (ADS)

    Farzinpour, Pouyan; Sundar, Aarthi; Gilroy, Kyle D.; Eskin, Zachary E.; Hughes, Robert A.; Neretina, Svetlana

    2013-02-01

    A substrate-based templated assembly route has been devised which offers large-area, high-throughput capabilities for the fabrication of periodic arrays of sub-micrometer and nanometer-scale structures. The approach overcomes a significant technological barrier to the widespread use of substrate-based templated assembly by eliminating the need for periodic templates having nanoscale features. Instead, it relies upon the use of a dynamic template with dimensions that evolve in time from easily fabricated micrometer dimensions to those on the nanoscale as the assembly process proceeds. The dynamic template consists of a pedestal of a sacrificial material, typically antimony, upon which an ultrathin layer of a second material is deposited. When heated, antimony sublimation results in a continuous reduction in template size where the motion of the sublimation fronts direct the diffusion of atoms of the second material to a predetermined location. The route has broad applicability, having already produced periodic arrays of gold, silver, copper, platinum, nickel, cobalt, germanium and Au-Ag alloys on substrates as diverse as silicon, sapphire, silicon-carbide, graphene and glass. Requiring only modest levels of instrumentation, the process provides an enabling route for any reasonably equipped researcher to fabricate periodic arrays that would otherwise require advanced fabrication facilities.A substrate-based templated assembly route has been devised which offers large-area, high-throughput capabilities for the fabrication of periodic arrays of sub-micrometer and nanometer-scale structures. The approach overcomes a significant technological barrier to the widespread use of substrate-based templated assembly by eliminating the need for periodic templates having nanoscale features. Instead, it relies upon the use of a dynamic template with dimensions that evolve in time from easily fabricated micrometer dimensions to those on the nanoscale as the assembly process

  18. Highly efficient ultrathin-film amorphous silicon solar cells on top of imprinted periodic nanodot arrays

    SciTech Connect

    Yan, Wensheng Gu, Min; Tao, Zhikuo; Ong, Thiam Min Brian

    2015-03-02

    The addressing of the light absorption and conversion efficiency is critical to the ultrathin-film hydrogenated amorphous silicon (a-Si:H) solar cells. We systematically investigate ultrathin a-Si:H solar cells with a 100 nm absorber on top of imprinted hexagonal nanodot arrays. Experimental evidences are demonstrated for not only notable silver nanodot arrays but also lower-cost ITO and Al:ZnO nanodot arrays. The measured external quantum efficiency is explained by the simulation results. The J{sub sc} values are 12.1, 13.0, and 14.3 mA/cm{sup 2} and efficiencies are 6.6%, 7.5%, and 8.3% for ITO, Al:ZnO, and silver nanodot arrays, respectively. Simulated optical absorption distribution shows high light trapping within amorphous silicon layer.

  19. Large-area 2D periodic crystalline silicon nanodome arrays on nanoimprinted glass exhibiting photonic band structure effects.

    PubMed

    Becker, C; Lockau, D; Sontheimer, T; Schubert-Bischoff, P; Rudigier-Voigt, E; Bockmeyer, M; Schmidt, F; Rech, B

    2012-04-01

    Two-dimensional silicon nanodome arrays are prepared on large areas up to 50 cm² exhibiting photonic band structure effects in the near-infrared and visible wavelength region by downscaling a recently developed fabrication method based on nanoimprint-patterned glass, high-rate electron-beam evaporation of silicon, self-organized solid phase crystallization and wet-chemical etching. The silicon nanodomes, arranged in square lattice geometry with 300 nm lattice constant, are optically characterized by angular resolved reflection measurements, allowing the partial determination of the photonic band structure. This experimentally determined band structure agrees well with the outcome of three-dimensional optical finite-element simulations. A 16% photonic bandgap is predicted for an optimized geometry of the silicon nanodome arrays. By variation of the duration of the selective etching step, the geometry as well as the optical properties of the periodic silicon nanodome arrays can be controlled systematically. PMID:22422473

  20. Dynamic templating: a large area processing route for the assembly of periodic arrays of sub-micrometer and nanoscale structures.

    PubMed

    Farzinpour, Pouyan; Sundar, Aarthi; Gilroy, Kyle D; Eskin, Zachary E; Hughes, Robert A; Neretina, Svetlana

    2013-03-01

    A substrate-based templated assembly route has been devised which offers large-area, high-throughput capabilities for the fabrication of periodic arrays of sub-micrometer and nanometer-scale structures. The approach overcomes a significant technological barrier to the widespread use of substrate-based templated assembly by eliminating the need for periodic templates having nanoscale features. Instead, it relies upon the use of a dynamic template with dimensions that evolve in time from easily fabricated micrometer dimensions to those on the nanoscale as the assembly process proceeds. The dynamic template consists of a pedestal of a sacrificial material, typically antimony, upon which an ultrathin layer of a second material is deposited. When heated, antimony sublimation results in a continuous reduction in template size where the motion of the sublimation fronts direct the diffusion of atoms of the second material to a predetermined location. The route has broad applicability, having already produced periodic arrays of gold, silver, copper, platinum, nickel, cobalt, germanium and Au-Ag alloys on substrates as diverse as silicon, sapphire, silicon-carbide, graphene and glass. Requiring only modest levels of instrumentation, the process provides an enabling route for any reasonably equipped researcher to fabricate periodic arrays that would otherwise require advanced fabrication facilities. PMID:23354129

  1. A miniature high resolution 3-D imaging sonar.

    PubMed

    Josserand, Tim; Wolley, Jason

    2011-04-01

    This paper discusses the design and development of a miniature, high resolution 3-D imaging sonar. The design utilizes frequency steered phased arrays (FSPA) technology. FSPAs present a small, low-power solution to the problem of underwater imaging sonars. The technology provides a method to build sonars with a large number of beams without the proportional power, circuitry and processing complexity. The design differs from previous methods in that the array elements are manufactured from a monolithic material. With this technique the arrays are flat and considerably smaller element dimensions are achievable which allows for higher frequency ranges and smaller array sizes. In the current frequency range, the demonstrated array has ultra high image resolution (1″ range×1° azimuth×1° elevation) and small size (<3″×3″). The design of the FSPA utilizes the phasing-induced frequency-dependent directionality of a linear phased array to produce multiple beams in a forward sector. The FSPA requires only two hardware channels per array and can be arranged in single and multiple array configurations that deliver wide sector 2-D images. 3-D images can be obtained by scanning the array in a direction perpendicular to the 2-D image field and applying suitable image processing to the multiple scanned 2-D images. This paper introduces the 3-D FSPA concept, theory and design methodology. Finally, results from a prototype array are presented and discussed. PMID:21112066

  2. Holography of incoherently illuminated 3D scenes

    NASA Astrophysics Data System (ADS)

    Shaked, Natan T.; Rosen, Joseph

    2008-04-01

    We review several methods of generating holograms of 3D realistic objects illuminated by incoherent white light. Using these methods, it is possible to obtain holograms with a simple digital camera, operating in regular light conditions. Thus, most disadvantages characterizing conventional holography, namely the need for a powerful, highly coherent laser and meticulous stability of the optical system are avoided. These holograms can be reconstructed optically by illuminating them with a coherent plane wave, or alternatively by using a digital reconstruction technique. In order to generate the proposed hologram, the 3D scene is captured from multiple points of view by a simple digital camera. Then, the acquired projections are digitally processed to yield the final hologram of the 3D scene. Based on this principle, we can generate Fourier, Fresnel, image or other types of holograms. To obtain certain advantages over the regular holograms, we also propose new digital holograms, such as modified Fresnel holograms and protected correlation holograms. Instead of shifting the camera mechanically to acquire a different projection of the 3D scene each time, it is possible to use a microlens array for acquiring the entire projections in a single camera shot. Alternatively, only the extreme projections can be acquired experimentally, while the middle projections are predicted digitally by using the view synthesis algorithm. The prospective goal of these methods is to facilitate the design of a simple, portable digital holographic camera which can be useful for a variety of practical applications.

  3. 3D printed diffractive terahertz lenses.

    PubMed

    Furlan, Walter D; Ferrando, Vicente; Monsoriu, Juan A; Zagrajek, Przemysław; Czerwińska, Elżbieta; Szustakowski, Mieczysław

    2016-04-15

    A 3D printer was used to realize custom-made diffractive THz lenses. After testing several materials, phase binary lenses with periodic and aperiodic radial profiles were designed and constructed in polyamide material to work at 0.625 THz. The nonconventional focusing properties of such lenses were assessed by computing and measuring their axial point spread function (PSF). Our results demonstrate that inexpensive 3D printed THz diffractive lenses can be reliably used in focusing and imaging THz systems. Diffractive THz lenses with unprecedented features, such as extended depth of focus or bifocalization, have been demonstrated. PMID:27082335

  4. Modular 3-D Transport model

    EPA Science Inventory

    MT3D was first developed by Chunmiao Zheng in 1990 at S.S. Papadopulos & Associates, Inc. with partial support from the U.S. Environmental Protection Agency (USEPA). Starting in 1990, MT3D was released as a pubic domain code from the USEPA. Commercial versions with enhanced capab...

  5. Market study: 3-D eyetracker

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A market study of a proposed version of a 3-D eyetracker for initial use at NASA's Ames Research Center was made. The commercialization potential of a simplified, less expensive 3-D eyetracker was ascertained. Primary focus on present and potential users of eyetrackers, as well as present and potential manufacturers has provided an effective means of analyzing the prospects for commercialization.

  6. LLNL-Earth3D

    2013-10-01

    Earth3D is a computer code designed to allow fast calculation of seismic rays and travel times through a 3D model of the Earth. LLNL is using this for earthquake location and global tomography efforts and such codes are of great interest to the Earth Science community.

  7. [3-D ultrasound in gastroenterology].

    PubMed

    Zoller, W G; Liess, H

    1994-06-01

    Three-dimensional (3D) sonography represents a development of noninvasive diagnostic imaging by real-time two-dimensional (2D) sonography. The use of transparent rotating scans, comparable to a block of glass, generates a 3D effect. The objective of the present study was to optimate 3D presentation of abdominal findings. Additional investigations were made with a new volumetric program to determine the volume of selected findings of the liver. The results were compared with the estimated volumes of 2D sonography and 2D computer tomography (CT). For the processing of 3D images, typical parameter constellations were found for the different findings, which facilitated processing of 3D images. In more than 75% of the cases examined we found an optimal 3D presentation of sonographic findings with respect to the evaluation criteria developed by us for the 3D imaging of processed data. Great differences were found for the estimated volumes of the findings of the liver concerning the three different techniques applied. 3D ultrasound represents a valuable method to judge morphological appearance in abdominal findings. The possibility of volumetric measurements enlarges its potential diagnostic significance. Further clinical investigations are necessary to find out if definite differentiation between benign and malign findings is possible. PMID:7919882

  8. 3D World Building System

    SciTech Connect

    2013-10-30

    This video provides an overview of the Sandia National Laboratories developed 3-D World Model Building capability that provides users with an immersive, texture rich 3-D model of their environment in minutes using a laptop and color and depth camera.

  9. 3D World Building System

    ScienceCinema

    None

    2014-02-26

    This video provides an overview of the Sandia National Laboratories developed 3-D World Model Building capability that provides users with an immersive, texture rich 3-D model of their environment in minutes using a laptop and color and depth camera.

  10. Dual side transparent OLED 3D display using Gabor super-lens

    NASA Astrophysics Data System (ADS)

    Chestak, Sergey; Kim, Dae-Sik; Cho, Sung-Woo

    2015-03-01

    We devised dual side transparent 3D display using transparent OLED panel and two lenticular arrays. The OLED panel is sandwiched between two parallel confocal lenticular arrays, forming Gabor super-lens. The display provides dual side stereoscopic 3D imaging and floating image of the object, placed behind it. The floating image can be superimposed with the displayed 3D image. The displayed autostereoscopic 3D images are composed of 4 views, each with resolution 64x90 pix.

  11. PLOT3D user's manual

    NASA Technical Reports Server (NTRS)

    Walatka, Pamela P.; Buning, Pieter G.; Pierce, Larry; Elson, Patricia A.

    1990-01-01

    PLOT3D is a computer graphics program designed to visualize the grids and solutions of computational fluid dynamics. Seventy-four functions are available. Versions are available for many systems. PLOT3D can handle multiple grids with a million or more grid points, and can produce varieties of model renderings, such as wireframe or flat shaded. Output from PLOT3D can be used in animation programs. The first part of this manual is a tutorial that takes the reader, keystroke by keystroke, through a PLOT3D session. The second part of the manual contains reference chapters, including the helpfile, data file formats, advice on changing PLOT3D, and sample command files.

  12. 3D printing in dentistry.

    PubMed

    Dawood, A; Marti Marti, B; Sauret-Jackson, V; Darwood, A

    2015-12-01

    3D printing has been hailed as a disruptive technology which will change manufacturing. Used in aerospace, defence, art and design, 3D printing is becoming a subject of great interest in surgery. The technology has a particular resonance with dentistry, and with advances in 3D imaging and modelling technologies such as cone beam computed tomography and intraoral scanning, and with the relatively long history of the use of CAD CAM technologies in dentistry, it will become of increasing importance. Uses of 3D printing include the production of drill guides for dental implants, the production of physical models for prosthodontics, orthodontics and surgery, the manufacture of dental, craniomaxillofacial and orthopaedic implants, and the fabrication of copings and frameworks for implant and dental restorations. This paper reviews the types of 3D printing technologies available and their various applications in dentistry and in maxillofacial surgery. PMID:26657435

  13. Observation of a periodic array of flux-closure quadrants in strained ferroelectric PbTiO3 films

    DOE PAGESBeta

    Tang, Y. L.; Zhu, Y. L; Ma, Xiuliang; Borisevich, Albina Y; Morozovska, A. N.; Eliseev, Eugene; Wang, W. Y; Wang, Yujia; Xu, Y. B.; Zhang, Z. D.; et al

    2015-05-01

    Nanoscale ferroelectrics are expected to exhibit various exotic domain configurations, such as the full flux-closure pattern that is well known in ferromagnetic materials. Here we observe not only the atomic morphology of the flux-closure quadrant but also a periodic array of flux closures in ferroelectric PbTiO3 films, mediated by tensile strain on a GdScO3 substrate. Using aberration-corrected scanning transmission electron microscopy, we directly visualize an alternating array of clockwise and counterclockwise flux closures, whose periodicity depends on the PbTiO3 film thickness. In the vicinity of the core, the strain is sufficient to rupture the lattice, with strain gradients up tomore » 109 per meter. We found engineering strain at the nanoscale may facilitate the development of nanoscale ferroelectric devices.« less

  14. PLOT3D/AMES, APOLLO UNIX VERSION USING GMR3D (WITH TURB3D)

    NASA Technical Reports Server (NTRS)

    Buning, P.

    1994-01-01

    PLOT3D is an interactive graphics program designed to help scientists visualize computational fluid dynamics (CFD) grids and solutions. Today, supercomputers and CFD algorithms can provide scientists with simulations of such highly complex phenomena that obtaining an understanding of the simulations has become a major problem. Tools which help the scientist visualize the simulations can be of tremendous aid. PLOT3D/AMES offers more functions and features, and has been adapted for more types of computers than any other CFD graphics program. Version 3.6b+ is supported for five computers and graphic libraries. Using PLOT3D, CFD physicists can view their computational models from any angle, observing the physics of problems and the quality of solutions. As an aid in designing aircraft, for example, PLOT3D's interactive computer graphics can show vortices, temperature, reverse flow, pressure, and dozens of other characteristics of air flow during flight. As critical areas become obvious, they can easily be studied more closely using a finer grid. PLOT3D is part of a computational fluid dynamics software cycle. First, a program such as 3DGRAPE (ARC-12620) helps the scientist generate computational grids to model an object and its surrounding space. Once the grids have been designed and parameters such as the angle of attack, Mach number, and Reynolds number have been specified, a "flow-solver" program such as INS3D (ARC-11794 or COS-10019) solves the system of equations governing fluid flow, usually on a supercomputer. Grids sometimes have as many as two million points, and the "flow-solver" produces a solution file which contains density, x- y- and z-momentum, and stagnation energy for each grid point. With such a solution file and a grid file containing up to 50 grids as input, PLOT3D can calculate and graphically display any one of 74 functions, including shock waves, surface pressure, velocity vectors, and particle traces. PLOT3D's 74 functions are organized into

  15. PLOT3D/AMES, APOLLO UNIX VERSION USING GMR3D (WITHOUT TURB3D)

    NASA Technical Reports Server (NTRS)

    Buning, P.

    1994-01-01

    PLOT3D is an interactive graphics program designed to help scientists visualize computational fluid dynamics (CFD) grids and solutions. Today, supercomputers and CFD algorithms can provide scientists with simulations of such highly complex phenomena that obtaining an understanding of the simulations has become a major problem. Tools which help the scientist visualize the simulations can be of tremendous aid. PLOT3D/AMES offers more functions and features, and has been adapted for more types of computers than any other CFD graphics program. Version 3.6b+ is supported for five computers and graphic libraries. Using PLOT3D, CFD physicists can view their computational models from any angle, observing the physics of problems and the quality of solutions. As an aid in designing aircraft, for example, PLOT3D's interactive computer graphics can show vortices, temperature, reverse flow, pressure, and dozens of other characteristics of air flow during flight. As critical areas become obvious, they can easily be studied more closely using a finer grid. PLOT3D is part of a computational fluid dynamics software cycle. First, a program such as 3DGRAPE (ARC-12620) helps the scientist generate computational grids to model an object and its surrounding space. Once the grids have been designed and parameters such as the angle of attack, Mach number, and Reynolds number have been specified, a "flow-solver" program such as INS3D (ARC-11794 or COS-10019) solves the system of equations governing fluid flow, usually on a supercomputer. Grids sometimes have as many as two million points, and the "flow-solver" produces a solution file which contains density, x- y- and z-momentum, and stagnation energy for each grid point. With such a solution file and a grid file containing up to 50 grids as input, PLOT3D can calculate and graphically display any one of 74 functions, including shock waves, surface pressure, velocity vectors, and particle traces. PLOT3D's 74 functions are organized into

  16. Preparations, Properties, and Applications of Periodic Nano Arrays using Anodized Aluminum Oxide and Di-block Copolymer

    NASA Astrophysics Data System (ADS)

    Noh, Kunbae

    2011-12-01

    Self-ordered arrangements observed in various materials systems such as anodic aluminum oxide, polystyrene nanoparticles, and block copolymer are of great interest in terms of providing new opportunities in nanofabrication field where lithographic techniques are broadly used in general. Investigations on self-assembled nano arrays to understand how to obtain periodic nano arrays in an efficient yet inexpensive way, and how to realize advanced material and device systems thereof, can lead to significant impacts on science and technology for many forefront device applications. In this thesis, various aspects of periodic nano-arrays have been discussed including novel preparations, properties and applications of anodized aluminum oxide (AAO) and PS-b-P4VP (S4VP) di-block copolymer self-assembly. First, long-range ordered AAO arrays have been demonstrated. Nanoimprint lithography (NIL) process allowed a faithful pattern transfer of the imprint mold pattern onto Al thin film, and interesting self-healing and pattern tripling phenomena were observed, which could be applicable towards fabrication of the NIL master mold having highly dense pattern over large area, useful for fabrication of a large-area substrate for predictable positioning of arrayed devices. Second, S4VP diblock copolymer self-assembly and S4VP directed AAO self-assembly have been demonstrated in the Al thin film on Si substrate. Such a novel combination of two dissimilar self-assembly techniques demonstrated a potential as a versatile tool for nanopatterning formation on a Si substrate, capable of being integrated into Si process technology. As exemplary applications, vertically aligned Ni nanowires have been synthesized into an S4VP-guided AAO membrane on a Si substrate in addition to anti-dot structured [Co/Pd]n magnetic multilayer using S4VP self assembly. Third, a highly hexagonally ordered, vertically parallel aluminum oxide nanotube array was successfully fabricated via hard anodization technique

  17. Liquid-bridging in particle self-assemblies toward constructing periodic nano-mesh structures and nano-dot arrays

    NASA Astrophysics Data System (ADS)

    Chul Park, Seung; Lee, In-Ho; Na, Jun-Hee; Lee, Sin-Doo

    2013-10-01

    We demonstrate a simple generic principle of constructing periodic nano-mesh structures and nano-dot arrays by liquid-bridging in particle self-assemblies. A self-assembly of nano- to micro-sized spheres of polystyrene, produced in a close-packed monolayer on a substrate by a convective method, is used as a template for liquid-bridging of a functional fluid in the pores among the neighboring particles. After the solidification of the fluid, followed by the detachment of the particles from the substrate, a periodic mesh structure is directly obtained. Moreover, deposition of a desired substance onto such mesh structure made of a sacrificial material, which is subsequently removable through a lift-off process, enables to produce a periodic dot array of the substance. Depending on the size of the particle and the nature of liquid bridging in the particle assembly, a variety of nano-mesh structures of silver-ink and nano-dot arrays of gold are constructed. This simple liquid bridging-based methodology is easily applicable for different classes of functional fluids such as soluble organic semiconductors.

  18. Visual inertia of rotating 3-D objects.

    PubMed

    Jiang, Y; Pantle, A J; Mark, L S

    1998-02-01

    Five experiments were designed to determine whether a rotating, transparent 3-D cloud of dots (simulated sphere) could influence the perceived direction of rotation of a subsequent sphere. Experiment 1 established conditions under which the direction of rotation of a virtual sphere was perceived unambiguously. When a near-far luminance difference and perspective depth cues were present, observers consistently saw the sphere rotate in the intended direction. In Experiment 2, a near-far luminance difference was used to create an unambiguous rotation sequence that was followed by a directionally ambiguous rotation sequence that lacked both the near-far luminance cue and the perspective cue. Observers consistently saw the second sequence as rotating in the same direction as the first, indicating the presence of 3-D visual inertia. Experiment 3 showed that 3-D visual inertia was sufficiently powerful to bias the perceived direction of a rotation sequence made unambiguous by a near-far luminance cue. Experiment 5 showed that 3-D visual inertia could be obtained using an occlusion depth cue to create an unambiguous inertia-inducing sequence. Finally, Experiments 2, 4, and 5 all revealed a fast-decay phase of inertia that lasted for approximately 800 msec, followed by an asymptotic phase that lasted for periods as long as 1,600 msec. The implications of these findings are examined with respect to motion mechanisms of 3-D visual inertia. PMID:9529911

  19. Bioprinting of 3D hydrogels.

    PubMed

    Stanton, M M; Samitier, J; Sánchez, S

    2015-08-01

    Three-dimensional (3D) bioprinting has recently emerged as an extension of 3D material printing, by using biocompatible or cellular components to build structures in an additive, layer-by-layer methodology for encapsulation and culture of cells. These 3D systems allow for cell culture in a suspension for formation of highly organized tissue or controlled spatial orientation of cell environments. The in vitro 3D cellular environments simulate the complexity of an in vivo environment and natural extracellular matrices (ECM). This paper will focus on bioprinting utilizing hydrogels as 3D scaffolds. Hydrogels are advantageous for cell culture as they are highly permeable to cell culture media, nutrients, and waste products generated during metabolic cell processes. They have the ability to be fabricated in customized shapes with various material properties with dimensions at the micron scale. 3D hydrogels are a reliable method for biocompatible 3D printing and have applications in tissue engineering, drug screening, and organ on a chip models. PMID:26066320

  20. Unassisted 3D camera calibration

    NASA Astrophysics Data System (ADS)

    Atanassov, Kalin; Ramachandra, Vikas; Nash, James; Goma, Sergio R.

    2012-03-01

    With the rapid growth of 3D technology, 3D image capture has become a critical part of the 3D feature set on mobile phones. 3D image quality is affected by the scene geometry as well as on-the-device processing. An automatic 3D system usually assumes known camera poses accomplished by factory calibration using a special chart. In real life settings, pose parameters estimated by factory calibration can be negatively impacted by movements of the lens barrel due to shaking, focusing, or camera drop. If any of these factors displaces the optical axes of either or both cameras, vertical disparity might exceed the maximum tolerable margin and the 3D user may experience eye strain or headaches. To make 3D capture more practical, one needs to consider unassisted (on arbitrary scenes) calibration. In this paper, we propose an algorithm that relies on detection and matching of keypoints between left and right images. Frames containing erroneous matches, along with frames with insufficiently rich keypoint constellations, are detected and discarded. Roll, pitch yaw , and scale differences between left and right frames are then estimated. The algorithm performance is evaluated in terms of the remaining vertical disparity as compared to the maximum tolerable vertical disparity.

  1. Arena3D: visualization of biological networks in 3D

    PubMed Central

    Pavlopoulos, Georgios A; O'Donoghue, Seán I; Satagopam, Venkata P; Soldatos, Theodoros G; Pafilis, Evangelos; Schneider, Reinhard

    2008-01-01

    Background Complexity is a key problem when visualizing biological networks; as the number of entities increases, most graphical views become incomprehensible. Our goal is to enable many thousands of entities to be visualized meaningfully and with high performance. Results We present a new visualization tool, Arena3D, which introduces a new concept of staggered layers in 3D space. Related data – such as proteins, chemicals, or pathways – can be grouped onto separate layers and arranged via layout algorithms, such as Fruchterman-Reingold, distance geometry, and a novel hierarchical layout. Data on a layer can be clustered via k-means, affinity propagation, Markov clustering, neighbor joining, tree clustering, or UPGMA ('unweighted pair-group method with arithmetic mean'). A simple input format defines the name and URL for each node, and defines connections or similarity scores between pairs of nodes. The use of Arena3D is illustrated with datasets related to Huntington's disease. Conclusion Arena3D is a user friendly visualization tool that is able to visualize biological or any other network in 3D space. It is free for academic use and runs on any platform. It can be downloaded or lunched directly from . Java3D library and Java 1.5 need to be pre-installed for the software to run. PMID:19040715

  2. Fdf in US3D

    NASA Astrophysics Data System (ADS)

    Otis, Collin; Ferrero, Pietro; Candler, Graham; Givi, Peyman

    2013-11-01

    The scalar filtered mass density function (SFMDF) methodology is implemented into the computer code US3D. This is an unstructured Eulerian finite volume hydrodynamic solver and has proven very effective for simulation of compressible turbulent flows. The resulting SFMDF-US3D code is employed for large eddy simulation (LES) on unstructured meshes. Simulations are conducted of subsonic and supersonic flows under non-reacting and reacting conditions. The consistency and the accuracy of the simulated results are assessed along with appraisal of the overall performance of the methodology. The SFMDF-US3D is now capable of simulating high speed flows in complex configurations.

  3. Periodic Si nanopillar arrays by anodic aluminum oxide template and catalytic etching for broadband and omnidirectional light harvesting.

    PubMed

    Wang, Hsin-Ping; Tsai, Kun-Tong; Lai, Kun-Yu; Wei, Tzu-Chiao; Wang, Yuh-Lin; He, Jr-Hau

    2012-01-01

    Large-area, periodic Si nanopillar arrays (NPAs) with the periodicity of 100 nm and the diameter of 60 nm were fabricated by metal-assisted chemical etching with anodic aluminum oxide as a patterning mask. The 100-nm-periodicity NPAs serve an antireflection function especially at the wavelengths of 200~400 nm, where the reflectance is decreased to be almost tenth of the value of the polished Si (from 62.9% to 7.9%). These NPAs show very low reflectance for broadband wavelengths and omnidirectional light incidence, attributed to the small periodicity and the stepped refractive index of NPA layers. The experimental results are confirmed by theoretical calculations. Raman scattering intensity was also found to be significantly increased with Si NPAs. The introduction of this industrial-scale self-assembly methodology for light PMID:22379674

  4. New 3D Bolton standards: coregistration of biplane x rays and 3D CT

    NASA Astrophysics Data System (ADS)

    Dean, David; Subramanyan, Krishna; Kim, Eun-Kyung

    1997-04-01

    The Bolton Standards 'normative' cohort (16 males, 16 females) have been invited back to the Bolton-Brush Growth Study Center for new biorthogonal plain film head x-rays and 3D (three dimensional) head CT-scans. A set of 29 3D landmarks were identified on both their biplane head film and 3D CT images. The current 3D CT image is then superimposed onto the landmarks collected from the current biplane head films. Three post-doctoral fellows have collected 37 3D landmarks from the Bolton Standards' 40 - 70 year old biplane head films. These films were captured annually during their growing period (ages 3 - 18). Using 29 of these landmarks the current 3D CT image is next warped (via thin plate spline) to landmarks taken from each participant's 18th year biplane head films, a process that is successively reiterated back to age 3. This process is demonstrated here for one of the Bolton Standards. The outer skull surfaces will be extracted from each warped 3D CT image and an average will be generated for each age/sex group. The resulting longitudinal series of average 'normative' boney skull surface images may be useful for craniofacial patient: diagnosis, treatment planning, stereotactic procedures, and outcomes assessment.

  5. Wavefront construction in 3-D

    SciTech Connect

    Chilcoat, S.R. Hildebrand, S.T.

    1995-12-31

    Travel time computation in inhomogeneous media is essential for pre-stack Kirchhoff imaging in areas such as the sub-salt province in the Gulf of Mexico. The 2D algorithm published by Vinje, et al, has been extended to 3D to compute wavefronts in complicated inhomogeneous media. The 3D wavefront construction algorithm provides many advantages over conventional ray tracing and other methods of computing travel times in 3D. The algorithm dynamically maintains a reasonably consistent ray density without making a priori guesses at the number of rays to shoot. The determination of caustics in 3D is a straight forward geometric procedure. The wavefront algorithm also enables the computation of multi-valued travel time surfaces.

  6. Heterodyne 3D ghost imaging

    NASA Astrophysics Data System (ADS)

    Yang, Xu; Zhang, Yong; Yang, Chenghua; Xu, Lu; Wang, Qiang; Zhao, Yuan

    2016-06-01

    Conventional three dimensional (3D) ghost imaging measures range of target based on pulse fight time measurement method. Due to the limit of data acquisition system sampling rate, range resolution of the conventional 3D ghost imaging is usually low. In order to take off the effect of sampling rate to range resolution of 3D ghost imaging, a heterodyne 3D ghost imaging (HGI) system is presented in this study. The source of HGI is a continuous wave laser instead of pulse laser. Temporal correlation and spatial correlation of light are both utilized to obtain the range image of target. Through theory analysis and numerical simulations, it is demonstrated that HGI can obtain high range resolution image with low sampling rate.

  7. Combinatorial 3D Mechanical Metamaterials

    NASA Astrophysics Data System (ADS)

    Coulais, Corentin; Teomy, Eial; de Reus, Koen; Shokef, Yair; van Hecke, Martin

    2015-03-01

    We present a class of elastic structures which exhibit 3D-folding motion. Our structures consist of cubic lattices of anisotropic unit cells that can be tiled in a complex combinatorial fashion. We design and 3d-print this complex ordered mechanism, in which we combine elastic hinges and defects to tailor the mechanics of the material. Finally, we use this large design space to encode smart functionalities such as surface patterning and multistability.

  8. Polarization sensitivity of light diffraction for periodic array of anisotropic gold nanoparticles

    SciTech Connect

    Tsai, Ming-shan Liu, Tung-kai; Tsen, Chun-yu; Ting, Chen-ching

    2015-06-15

    This article aims to analyze the first order diffraction intensity of the incident polarized light which is diffracted by the gold nanoparticles array in terms of the surface plasmon effect. The inspected gold nanoparticles array films are built in grating pattern with stripe thickness of 4 μm and diameters of gold nanoparticles ca. 10–56 nm, which are formed by annealing at temperatures of 400, 450, 500, and 550 °C, respectively. The probing light is linearly polarized with wavelengths of 450–800 nm and counterclockwise turns its polarization direction from 0° to 90° during measurements. The results show that the diffraction intensity depends on the anisotropic configuration samples which gold nanoparticles are orientated by analyzing the scanning electron microscope images. It results that the localized surface plasmon effect induced by incident field depends on orientation and causes the sample polarization-sensitive.

  9. Periodic Application of Concurrent Error Detection in Processor Array Architectures. PhD. Thesis -

    NASA Technical Reports Server (NTRS)

    Chen, Paul Peichuan

    1993-01-01

    Processor arrays can provide an attractive architecture for some applications. Featuring modularity, regular interconnection and high parallelism, such arrays are well-suited for VLSI/WSI implementations, and applications with high computational requirements, such as real-time signal processing. Preserving the integrity of results can be of paramount importance for certain applications. In these cases, fault tolerance should be used to ensure reliable delivery of a system's service. One aspect of fault tolerance is the detection of errors caused by faults. Concurrent error detection (CED) techniques offer the advantage that transient and intermittent faults may be detected with greater probability than with off-line diagnostic tests. Applying time-redundant CED techniques can reduce hardware redundancy costs. However, most time-redundant CED techniques degrade a system's performance.

  10. 3-D Cavern Enlargement Analyses

    SciTech Connect

    EHGARTNER, BRIAN L.; SOBOLIK, STEVEN R.

    2002-03-01

    Three-dimensional finite element analyses simulate the mechanical response of enlarging existing caverns at the Strategic Petroleum Reserve (SPR). The caverns are located in Gulf Coast salt domes and are enlarged by leaching during oil drawdowns as fresh water is injected to displace the crude oil from the caverns. The current criteria adopted by the SPR limits cavern usage to 5 drawdowns (leaches). As a base case, 5 leaches were modeled over a 25 year period to roughly double the volume of a 19 cavern field. Thirteen additional leaches where then simulated until caverns approached coalescence. The cavern field approximated the geometries and geologic properties found at the West Hackberry site. This enabled comparisons are data collected over nearly 20 years to analysis predictions. The analyses closely predicted the measured surface subsidence and cavern closure rates as inferred from historic well head pressures. This provided the necessary assurance that the model displacements, strains, and stresses are accurate. However, the cavern field has not yet experienced the large scale drawdowns being simulated. Should they occur in the future, code predictions should be validated with actual field behavior at that time. The simulations were performed using JAS3D, a three dimensional finite element analysis code for nonlinear quasi-static solids. The results examine the impacts of leaching and cavern workovers, where internal cavern pressures are reduced, on surface subsidence, well integrity, and cavern stability. The results suggest that the current limit of 5 oil drawdowns may be extended with some mitigative action required on the wells and later on to surface structure due to subsidence strains. The predicted stress state in the salt shows damage to start occurring after 15 drawdowns with significant failure occurring at the 16th drawdown, well beyond the current limit of 5 drawdowns.

  11. The EISCAT_3D Science Case

    NASA Astrophysics Data System (ADS)

    Tjulin, A.; Mann, I.; McCrea, I.; Aikio, A. T.

    2013-05-01

    EISCAT_3D will be a world-leading international research infrastructure using the incoherent scatter technique to study the atmosphere in the Fenno-Scandinavian Arctic and to investigate how the Earth's atmosphere is coupled to space. The EISCAT_3D phased-array multistatic radar system will be operated by EISCAT Scientific Association and thus be an integral part of an organisation that has successfully been running incoherent scatter radars for more than thirty years. The baseline design of the radar system contains a core site with transmitting and receiving capabilities located close to the intersection of the Swedish, Norwegian and Finnish borders and five receiving sites located within 50 to 250 km from the core. The EISCAT_3D project is currently in its Preparatory Phase and can smoothly transit into implementation in 2014, provided sufficient funding. Construction can start 2016 and first operations in 2018. The EISCAT_3D Science Case is prepared as part of the Preparatory Phase. It is regularly updated with annual new releases, and it aims at being a common document for the whole future EISCAT_3D user community. The areas covered by the Science Case are atmospheric physics and global change; space and plasma physics; solar system research; space weather and service applications; and radar techniques, new methods for coding and analysis. Two of the aims for EISCAT_3D are to understand the ways natural variability in the upper atmosphere, imposed by the Sun-Earth system, can influence the middle and lower atmosphere, and to improve the predictivity of atmospheric models by providing higher resolution observations to replace the current parametrised input. Observations by EISCAT_3D will also be used to monitor the direct effects from the Sun on the ionosphere-atmosphere system and those caused by solar wind magnetosphere-ionosphere interaction. In addition, EISCAT_3D will be used for remote sensing the large-scale behaviour of the magnetosphere from its

  12. Versatile pattern generation of periodic, high aspect ratio Si nanostructure arrays with sub-50-nm resolution on a wafer scale

    PubMed Central

    2013-01-01

    We report on a method of fabricating variable patterns of periodic, high aspect ratio silicon nanostructures with sub-50-nm resolution on a wafer scale. The approach marries step-and-repeat nanoimprint lithography (NIL) and metal-catalyzed electroless etching (MCEE), enabling near perfectly ordered Si nanostructure arrays of user-defined patterns to be controllably and rapidly generated on a wafer scale. Periodic features possessing circular, hexagonal, and rectangular cross-sections with lateral dimensions down to sub-50 nm, in hexagonal or square array configurations and high array packing densities up to 5.13 × 107 structures/mm2 not achievable by conventional UV photolithography are fabricated using this top-down approach. By suitably tuning the duration of catalytic etching, variable aspect ratio Si nanostructures can be formed. As the etched Si pattern depends largely on the NIL mould which is patterned by electron beam lithography (EBL), the technique can be used to form patterns not possible with self-assembly methods, nanosphere, and interference lithography for replication on a wafer scale. Good chemical resistance of the nanoimprinted mask and adhesion to the Si substrate facilitate good pattern transfer and preserve the smooth top surface morphology of the Si nanostructures as shown in TEM. This approach is suitable for generating Si nanostructures of controlled dimensions and patterns, with high aspect ratio on a wafer level suitable for semiconductor device production. PMID:24289275

  13. Versatile pattern generation of periodic, high aspect ratio Si nanostructure arrays with sub-50-nm resolution on a wafer scale

    NASA Astrophysics Data System (ADS)

    Ho, Jian-Wei; Wee, Qixun; Dumond, Jarrett; Tay, Andrew; Chua, Soo-Jin

    2013-12-01

    We report on a method of fabricating variable patterns of periodic, high aspect ratio silicon nanostructures with sub-50-nm resolution on a wafer scale. The approach marries step-and-repeat nanoimprint lithography (NIL) and metal-catalyzed electroless etching (MCEE), enabling near perfectly ordered Si nanostructure arrays of user-defined patterns to be controllably and rapidly generated on a wafer scale. Periodic features possessing circular, hexagonal, and rectangular cross-sections with lateral dimensions down to sub-50 nm, in hexagonal or square array configurations and high array packing densities up to 5.13 × 107 structures/mm2 not achievable by conventional UV photolithography are fabricated using this top-down approach. By suitably tuning the duration of catalytic etching, variable aspect ratio Si nanostructures can be formed. As the etched Si pattern depends largely on the NIL mould which is patterned by electron beam lithography (EBL), the technique can be used to form patterns not possible with self-assembly methods, nanosphere, and interference lithography for replication on a wafer scale. Good chemical resistance of the nanoimprinted mask and adhesion to the Si substrate facilitate good pattern transfer and preserve the smooth top surface morphology of the Si nanostructures as shown in TEM. This approach is suitable for generating Si nanostructures of controlled dimensions and patterns, with high aspect ratio on a wafer level suitable for semiconductor device production.

  14. FELIX: a volumetric 3D laser display

    NASA Astrophysics Data System (ADS)

    Bahr, Detlef; Langhans, Knut; Gerken, Martin; Vogt, Carsten; Bezecny, Daniel; Homann, Dennis

    1996-03-01

    In this paper, an innovative approach of a true 3D image presentation in a space filling, volumetric laser display will be described. The introduced prototype system is based on a moving target screen that sweeps the display volume. Net result is the optical equivalent of a 3D array of image points illuminated to form a model of the object which occupies a physical space. Wireframe graphics are presented within the display volume which a group of people can walk around and examine simultaneously from nearly any orientation and without any visual aids. Further to the detailed vector scanning mode, a raster scanned system and a combination of both techniques are under development. The volumetric 3D laser display technology for true reproduction of spatial images can tremendously improve the viewers ability to interpret data and to reliably determine distance, shape and orientation. Possible applications for this development range from air traffic control, where moving blips of light represent individual aircrafts in a true to scale projected airspace of an airport, to various medical applications (e.g. electrocardiography, computer-tomography), to entertainment and education visualization as well as imaging in the field of engineering and Computer Aided Design.

  15. High-efficiency p-i-n superstrate amorphous Si solar cells on SiO x periodic arrays of three-dimensional microstructure prepared by soft imprinting

    NASA Astrophysics Data System (ADS)

    Niikura, Chisato; Chowdhury, Amartya; Janthong, Bancha; Sichanugrist, Porponth; Konagai, Makoto

    2016-04-01

    Efficient amorphous Si thin-film solar cells in a p-i-n superstrate configuration with a high initial conversion efficiency of 10.3% were successfully fabricated on periodically three-dimensional (3D) micropatterned SiO x /glass substrates prepared by soft imprinting. Conformal film deposition on a 3D microstructure was realized owing to the shape of our newly designed 3D pattern and the triode plasma-enhanced CVD technique, which enables the selective transport of favorable film precursors to the substrate surface. The nanoscale surface texture of the front transparent conductive oxide layer was found to be crucial for optical confinement, unexceptionally for amorphous Si solar cells on a 3D microstructure, which results in an improved short-circuit current density.

  16. From 3D view to 3D print

    NASA Astrophysics Data System (ADS)

    Dima, M.; Farisato, G.; Bergomi, M.; Viotto, V.; Magrin, D.; Greggio, D.; Farinato, J.; Marafatto, L.; Ragazzoni, R.; Piazza, D.

    2014-08-01

    In the last few years 3D printing is getting more and more popular and used in many fields going from manufacturing to industrial design, architecture, medical support and aerospace. 3D printing is an evolution of bi-dimensional printing, which allows to obtain a solid object from a 3D model, realized with a 3D modelling software. The final product is obtained using an additive process, in which successive layers of material are laid down one over the other. A 3D printer allows to realize, in a simple way, very complex shapes, which would be quite difficult to be produced with dedicated conventional facilities. Thanks to the fact that the 3D printing is obtained superposing one layer to the others, it doesn't need any particular work flow and it is sufficient to simply draw the model and send it to print. Many different kinds of 3D printers exist based on the technology and material used for layer deposition. A common material used by the toner is ABS plastics, which is a light and rigid thermoplastic polymer, whose peculiar mechanical properties make it diffusely used in several fields, like pipes production and cars interiors manufacturing. I used this technology to create a 1:1 scale model of the telescope which is the hardware core of the space small mission CHEOPS (CHaracterising ExOPlanets Satellite) by ESA, which aims to characterize EXOplanets via transits observations. The telescope has a Ritchey-Chrétien configuration with a 30cm aperture and the launch is foreseen in 2017. In this paper, I present the different phases for the realization of such a model, focusing onto pros and cons of this kind of technology. For example, because of the finite printable volume (10×10×12 inches in the x, y and z directions respectively), it has been necessary to split the largest parts of the instrument in smaller components to be then reassembled and post-processed. A further issue is the resolution of the printed material, which is expressed in terms of layers

  17. 3D ¹⁵N/¹⁵N/¹H chemical shift correlation experiment utilizing an RFDR-based ¹H/¹H mixing period at 100 kHz MAS.

    PubMed

    Nishiyama, Yusuke; Malon, Michal; Ishii, Yuji; Ramamoorthy, Ayyalusamy

    2014-07-01

    Homonuclear correlation NMR experiments are commonly used in the high-resolution structural studies of proteins. While (13)C/(13)C chemical shift correlation experiments utilizing dipolar recoupling techniques are fully utilized under MAS, correlation of the chemical shifts of (15)N nuclei in proteins has been a challenge. Previous studies have shown that the negligible (15)N-(15)N dipolar coupling in peptides or proteins necessitates the use of a very long mixing time (typically several seconds) for effective spin diffusion to occur and considerably slows down a (15)N/(15)N correlation experiment. In this study, we show that the use of mixing proton magnetization, instead of (15)N, via the recoupled (1)H-(1)H dipolar couplings enable faster (15)N/(15)N correlation. In addition, the use of proton-detection under ultrafast MAS overcomes the sensitivity loss due to multiple magnetization transfer (between (1)H and (15)N nuclei) steps. In fact, less than 300 nL (∼1.1 micromole quantity) sample is sufficient to acquire the 3D spectrum within 5 h. Our results also demonstrate that a 3D (15)N/(15)N/(1)H experiment can render higher resolution spectra that will be useful in the structural studies of proteins at ultrafast MAS frequencies. 3D (15)N/(15)N/(1)H and 2D radio frequency-driven dipolar recoupling (RFDR)-based (1)H/(1)H experimental results obtained from a powder sample of N-acetyla-L-(15)N-valyl-L-(15)N-leucine at 70 and 100kHz MAS frequencies are presented. PMID:24801998

  18. YouDash3D: exploring stereoscopic 3D gaming for 3D movie theaters

    NASA Astrophysics Data System (ADS)

    Schild, Jonas; Seele, Sven; Masuch, Maic

    2012-03-01

    Along with the success of the digitally revived stereoscopic cinema, events beyond 3D movies become attractive for movie theater operators, i.e. interactive 3D games. In this paper, we present a case that explores possible challenges and solutions for interactive 3D games to be played by a movie theater audience. We analyze the setting and showcase current issues related to lighting and interaction. Our second focus is to provide gameplay mechanics that make special use of stereoscopy, especially depth-based game design. Based on these results, we present YouDash3D, a game prototype that explores public stereoscopic gameplay in a reduced kiosk setup. It features live 3D HD video stream of a professional stereo camera rig rendered in a real-time game scene. We use the effect to place the stereoscopic effigies of players into the digital game. The game showcases how stereoscopic vision can provide for a novel depth-based game mechanic. Projected trigger zones and distributed clusters of the audience video allow for easy adaptation to larger audiences and 3D movie theater gaming.

  19. Microseismicity and b-values of the Wabash Valley Intraplate Seismic Zone from short-period phased arrays

    NASA Astrophysics Data System (ADS)

    Conder, J. A.; Milliron, K.; Zhu, L.

    2014-12-01

    Two phased arrays of 9 short-period stations each are currently recording in the Wabash Valley Seismic Zone (WVSZ) as part of the EarthScope Wabash FlexArray project. The phased arrays aim to address the level of microseismicity produced by the intraplate seismic zone. Although seismic hazard maps of the U.S. Midwest are dominated by the New Madrid Seismic Zone (NMSZ), the WVSZ has released 40% more seismic energy than the NMSZ over the last half century with four events larger than M5 and only one in the NMSZ reaching that threshold. A comparison of event frequency statistics suggests two markedly different systems. The NMSZ exhibits b-values near unity, but the WVSZ exhibits much smaller b-values in the 0.6-0.7 range. Deviations less than unity may be controlled through crack geometry and/or greater shear stresses possibly indicating a time-dependent, or migrating, behavior in mid-continent. Alternatively, it may be the case that the low b-values are simply a reflection of less complete catalog than the NMSZ. A previous short-term microseismicity study of the WVSZ shows a dearth of non-anthropogenic sources in the Wabash. The phased array near the central portion of the WVSZ largely confirms the previously noted lack of substantial natural seismicity along the central portion of the fault system and the associated low b-values. However, the phased array near the southern termination of the fault system shows significantly more activity. Importantly, the largest events from the Wabash, including the 2008 M5.4 Mt. Carmel and the 1968 M5.5 Harrisburg events occurred near the northern and southern ends of the fault system. The phased arrays seem to indicate different portions of the fault system yielding different levels of activity. As the catalogs become more complete, there is a preliminary suggestion that the anomalously low b-values for the Wabash do not denote a system under significantly larger stresses, but rather a conflation of regions along-strike of the

  20. Application of geologic-mathematical 3D modeling for complex structure deposits by the example of Lower- Cretaceous period depositions in Western Ust - Balykh oil field (Khanty-Mansiysk Autonomous District)

    NASA Astrophysics Data System (ADS)

    Perevertailo, T.; Nedolivko, N.; Prisyazhnyuk, O.; Dolgaya, T.

    2015-11-01

    The complex structure of the Lower-Cretaceous formation by the example of the reservoir BC101 in Western Ust - Balykh Oil Field (Khanty-Mansiysk Autonomous District) has been studied. Reservoir range relationships have been identified. 3D geologic- mathematical modeling technique considering the heterogeneity and variability of a natural reservoir structure has been suggested. To improve the deposit geological structure integrity methods of mathematical statistics were applied, which, in its turn, made it possible to obtain equal probability models with similar input data and to consider the formation conditions of reservoir rocks and cap rocks.

  1. 3D barcodes: theoretical aspects and practical implementation

    NASA Astrophysics Data System (ADS)

    Gladstein, David; Kakarala, Ramakrishna; Baharav, Zachi

    2015-02-01

    This paper introduces the concept of three dimensional (3D) barcodes. A 3D barcode is composed of an array of 3D cells, called modules, and each can be either filled or empty, corresponding to two possible values of a bit. These barcodes have great theoretical promise thanks to their very large information capacity, which grows as the cube of the linear size of the barcode, and in addition are becoming practically manufacturable thanks to the ubiquitous use of 3D printers. In order to make these 3D barcodes practical for consumers, it is important to keep the decoding simple using commonly available means like smartphones. We therefore limit ourselves to decoding mechanisms based only on three projections of the barcode, which imply specific constraints on the barcode itself. The three projections produce the marginal sums of the 3D cube, which are the counts of filled-in modules along each Cartesian axis. In this paper we present some of the theoretical aspects of the 2D and 3D cases, and describe the resulting complexity of the 3D case. We then describe a method to reduce these complexities into a practical application. The method features an asymmetric coding scheme, where the decoder is much simpler than the encoder. We close by demonstrating 3D barcodes we created and their usability.

  2. Speaking Volumes About 3-D

    NASA Technical Reports Server (NTRS)

    2002-01-01

    In 1999, Genex submitted a proposal to Stennis Space Center for a volumetric 3-D display technique that would provide multiple users with a 360-degree perspective to simultaneously view and analyze 3-D data. The futuristic capabilities of the VolumeViewer(R) have offered tremendous benefits to commercial users in the fields of medicine and surgery, air traffic control, pilot training and education, computer-aided design/computer-aided manufacturing, and military/battlefield management. The technology has also helped NASA to better analyze and assess the various data collected by its satellite and spacecraft sensors. Genex capitalized on its success with Stennis by introducing two separate products to the commercial market that incorporate key elements of the 3-D display technology designed under an SBIR contract. The company Rainbow 3D(R) imaging camera is a novel, three-dimensional surface profile measurement system that can obtain a full-frame 3-D image in less than 1 second. The third product is the 360-degree OmniEye(R) video system. Ideal for intrusion detection, surveillance, and situation management, this unique camera system offers a continuous, panoramic view of a scene in real time.

  3. Analysis and experimental realization of locally resonant phononic plates carrying a periodic array of beam-like resonators

    NASA Astrophysics Data System (ADS)

    Xiao, Yong; Wen, Jihong; Huang, Lingzhi; Wen, Xisen

    2014-01-01

    We present theoretical examination and experimental demonstration of locally resonant (LR) phononic plates consisting of a periodic array of beam-like resonators attached to a thin homogeneous plate. Such phononic plates feature unique wave physics due to the coexistence of localized resonance and structural periodicity. We demonstrate that a low-frequency complete band gap for flexural plate waves can be created in the proposed structure owing to the interaction between the localized resonant modes of the beam-like resonators and the flexural wave modes of the host plate. We show that the location and width of the complete band gap can be dramatically tuned by changing the properties of the beam-like resonators. To understand the opening mechanism and evolution behaviour of the complete band gap, some approximate but explicit models are provided and discussed. We further perform experimental measurements of a specimen fabricated by an array of double-stacked aluminum beam-like resonators attached to a thin aluminum plate with 5 cm structure periodicity. The experimental results evidence a complete band gap extending from 465 to 860 Hz, matching well with our theoretical prediction. The LR phononic plates proposed in this work can find potential applications in attenuation of low-frequency mechanical vibrations and insulation of low-frequency audible sound.

  4. A 3-D SAR approach to IFSAR processing

    SciTech Connect

    DOERRY,ARMIN W.; BICKEL,DOUGLAS L.

    2000-03-01

    Interferometric SAR (IFSAR) can be shown to be a special case of 3-D SAR image formation. In fact, traditional IFSAR processing results in the equivalent of merely a super-resolved, under-sampled, 3-D SAR image. However, when approached as a 3-D SAR problem, a number of IFSAR properties and anomalies are easily explained. For example, IFSAR decorrelation with height is merely ordinary migration in 3-D SAR. Consequently, treating IFSAR as a 3-D SAR problem allows insight and development of proper motion compensation techniques and image formation operations to facilitate optimal height estimation. Furthermore, multiple antenna phase centers and baselines are easily incorporated into this formulation, providing essentially a sparse array in the elevation dimension. This paper shows the Polar Format image formation algorithm extended to 3 dimensions, and then proceeds to apply it to the IFSAR collection geometry. This suggests a more optimal reordering of the traditional IFSAR processing steps.

  5. 3D augmented reality with integral imaging display

    NASA Astrophysics Data System (ADS)

    Shen, Xin; Hua, Hong; Javidi, Bahram

    2016-06-01

    In this paper, a three-dimensional (3D) integral imaging display for augmented reality is presented. By implementing the pseudoscopic-to-orthoscopic conversion method, elemental image arrays with different capturing parameters can be transferred into the identical format for 3D display. With the proposed merging algorithm, a new set of elemental images for augmented reality display is generated. The newly generated elemental images contain both the virtual objects and real world scene with desired depth information and transparency parameters. The experimental results indicate the feasibility of the proposed 3D augmented reality with integral imaging.

  6. 3D Integration for Wireless Multimedia

    NASA Astrophysics Data System (ADS)

    Kimmich, Georg

    The convergence of mobile phone, internet, mapping, gaming and office automation tools with high quality video and still imaging capture capability is becoming a strong market trend for portable devices. High-density video encode and decode, 3D graphics for gaming, increased application-software complexity and ultra-high-bandwidth 4G modem technologies are driving the CPU performance and memory bandwidth requirements close to the PC segment. These portable multimedia devices are battery operated, which requires the deployment of new low-power-optimized silicon process technologies and ultra-low-power design techniques at system, architecture and device level. Mobile devices also need to comply with stringent silicon-area and package-volume constraints. As for all consumer devices, low production cost and fast time-to-volume production is key for success. This chapter shows how 3D architectures can bring a possible breakthrough to meet the conflicting power, performance and area constraints. Multiple 3D die-stacking partitioning strategies are described and analyzed on their potential to improve the overall system power, performance and cost for specific application scenarios. Requirements and maturity of the basic process-technology bricks including through-silicon via (TSV) and die-to-die attachment techniques are reviewed. Finally, we highlight new challenges which will arise with 3D stacking and an outlook on how they may be addressed: Higher power density will require thermal design considerations, new EDA tools will need to be developed to cope with the integration of heterogeneous technologies and to guarantee signal and power integrity across the die stack. The silicon/wafer test strategies have to be adapted to handle high-density IO arrays, ultra-thin wafers and provide built-in self-test of attached memories. New standards and business models have to be developed to allow cost-efficient assembly and testing of devices from different silicon and technology

  7. 3D-Printed Microfluidics.

    PubMed

    Au, Anthony K; Huynh, Wilson; Horowitz, Lisa F; Folch, Albert

    2016-03-14

    The advent of soft lithography allowed for an unprecedented expansion in the field of microfluidics. However, the vast majority of PDMS microfluidic devices are still made with extensive manual labor, are tethered to bulky control systems, and have cumbersome user interfaces, which all render commercialization difficult. On the other hand, 3D printing has begun to embrace the range of sizes and materials that appeal to the developers of microfluidic devices. Prior to fabrication, a design is digitally built as a detailed 3D CAD file. The design can be assembled in modules by remotely collaborating teams, and its mechanical and fluidic behavior can be simulated using finite-element modeling. As structures are created by adding materials without the need for etching or dissolution, processing is environmentally friendly and economically efficient. We predict that in the next few years, 3D printing will replace most PDMS and plastic molding techniques in academia. PMID:26854878

  8. Experimental study on the effect of boundary condition for transmission properties of periodical metal hole arrays in terahertz range

    NASA Astrophysics Data System (ADS)

    Xu, Jiaming; Xie, Le; Gao, Chunmei; Li, Zhou; Chen, Lin; Zhu, Yiming

    2013-08-01

    A metal hole arrays terahertz filter based on surface plasmon polaritons and fabricated by aluminum slab of different holes scales have been experimentally investigated by using THz time-domain spectroscopy system from 0.1 to 2.7 THz. The experiment results indicated there is a transmission peak at 0.26 THz, approximately. The results in simulation by finite element method agree well with the experimental one for the big scale sample. The mismatch of experimental and simulated results for small scale sample can be attributed to boundary condition and insufficient periodical extension. Further, the theoretical analyses about extraordinary optical transmission and filter phenomena are also discussed.

  9. Accommodation response measurements for integral 3D image

    NASA Astrophysics Data System (ADS)

    Hiura, H.; Mishina, T.; Arai, J.; Iwadate, Y.

    2014-03-01

    We measured accommodation responses under integral photography (IP), binocular stereoscopic, and real object display conditions, and viewing conditions of binocular and monocular viewing conditions. The equipment we used was an optometric device and a 3D display. We developed the 3D display for IP and binocular stereoscopic images that comprises a high-resolution liquid crystal display (LCD) and a high-density lens array. The LCD has a resolution of 468 dpi and a diagonal size of 4.8 inches. The high-density lens array comprises 106 x 69 micro lenses that have a focal length of 3 mm and diameter of 1 mm. The lenses are arranged in a honeycomb pattern. The 3D display was positioned 60 cm from an observer under IP and binocular stereoscopic display conditions. The target was presented at eight depth positions relative to the 3D display: 15, 10, and 5 cm in front of the 3D display, on the 3D display panel, and 5, 10, 15 and 30 cm behind the 3D display under the IP and binocular stereoscopic display conditions. Under the real object display condition, the target was displayed on the 3D display panel, and the 3D display was placed at the eight positions. The results suggest that the IP image induced more natural accommodation responses compared to the binocular stereoscopic image. The accommodation responses of the IP image were weaker than those of a real object; however, they showed a similar tendency with those of the real object under the two viewing conditions. Therefore, IP can induce accommodation to the depth positions of 3D images.

  10. 3D Computations and Experiments

    SciTech Connect

    Couch, R; Faux, D; Goto, D; Nikkel, D

    2004-04-05

    This project consists of two activities. Task A, Simulations and Measurements, combines all the material model development and associated numerical work with the materials-oriented experimental activities. The goal of this effort is to provide an improved understanding of dynamic material properties and to provide accurate numerical representations of those properties for use in analysis codes. Task B, ALE3D Development, involves general development activities in the ALE3D code with the focus of improving simulation capabilities for problems of mutual interest to DoD and DOE. Emphasis is on problems involving multi-phase flow, blast loading of structures and system safety/vulnerability studies.

  11. 3D Computations and Experiments

    SciTech Connect

    Couch, R; Faux, D; Goto, D; Nikkel, D

    2003-05-12

    This project is in its first full year after the combining of two previously funded projects: ''3D Code Development'' and ''Dynamic Material Properties''. The motivation behind this move was to emphasize and strengthen the ties between the experimental work and the computational model development in the materials area. The next year's activities will indicate the merging of the two efforts. The current activity is structured in two tasks. Task A, ''Simulations and Measurements'', combines all the material model development and associated numerical work with the materials-oriented experimental activities. Task B, ''ALE3D Development'', is a continuation of the non-materials related activities from the previous project.

  12. Periodic arrays of intercalated atoms in twisted bilayer graphene: An ab initio investigation

    NASA Astrophysics Data System (ADS)

    Miwa, R. H.; Venezuela, P.; Morell, Eric Suárez

    2015-09-01

    We have performed an ab initio investigation of transition metals (TMs =Mo ,Ru ,Co ,andPt ) embedded in twisted bilayer graphene (tBG) layers. Our total energy results reveal that, triggered by the misalignment between the graphene layers, Mo and Ru atoms may form a quasiperiodic (triangular) array of intercalated atoms. In contrast, the formation of those structures is not expected for the other TMs, the Co and Pt atoms. The net magnetic moment (m ) of Mo and Ru atoms may be quenched upon intercalation, depending on the stacking region (AA or AB). For instance, we find a magnetic moment of 0.3 μB(1.8 μB) for Ru atoms intercalated between the AA (AB) regions of the stacked twisted layers. Through simulated scanning tunneling microscopy (STM) images, we verify that the presence of intercalated TMs can be identified by the formation of bright (hexagonal) spots lying on the graphene surface.

  13. Assembly of multi-functional nanocomponents on periodic nanotube array for biosensors

    PubMed Central

    Yu, Y.; Cimeno, A.; Lan, Y. C.; Rybczynski, J.; Wang, D. Z.; Paudel, T.; Ren, Z. F.; Wagner, D. J.; Qiu, M. Q.; Chiles, T. C.; Cai, D.

    2009-01-01

    Patterned carbon nanotubes arrays (PCNTA) with reduced density and length were developed with polystyrene sphere masked catalyst dots followed by plasma enhanced chemical vapor deposition method. The nanotubes were then uniformly coated with electropolymerized polypyrrole (PPy). The coating thickness was conformally adjustable. Gold nanoparticles (AuNP) together with glucose oxidase (Gox) were doped into the PPy film on the nanotubes to develop a high performance PCNTA glucose sensor. The sensitivity of the sensor was improved by the co-existence of Gox and AuNP on the carbon nanotube. Moreover, in contrast to previous reported PCNTA glucose sensors, the design herein utilized the entire surface of nanotubes as active sensing areas in order to maximize the Faradic currents. This research outlines a practical avenue to fabricate high performance PCNTA sensor chips with multiple molecules and functional nano-architectures. PMID:19829755

  14. Optimization of the particle density to maximize the SERS enhancement factor of periodic plasmonic nanostructure array.

    PubMed

    Wei, Shuhua; Zheng, Mengjie; Xiang, Quan; Hu, Hailong; Duan, Huigao

    2016-09-01

    Low-cost surface-enhanced Raman scattering (SERS) substrate with the largest possible enhancement factor is highly desirable for SERS-based sensing applications. In this work, we systematically investigated how the density of plasmonic nanostructures affects the intensity of SERS signal. By directly depositing of metallic layer on electron-beam-lithography defined dielectric nanoposts, plasmonic structures array with different densities were reliably fabricated for SERS measurements. Two main experimental phenomena were obtained: (1) the SERS intensity did not increase monotonically when increasing the density of plasmonic structures, and (2) these ultra-dense plasmonic structures resulted in the maximal SERS intensity. These results could be well explained based on finite-difference time domain (FDTD) simulations and provide robust experimental evidences to guide the design of the best possible SERS substrate. PMID:27607665

  15. Reconstruction of 2D seismic wavefield from Long-Period Seismogram and Short-Period Seismogram Envelope by Seismic Gradiometry applied to the Hi-net Array

    NASA Astrophysics Data System (ADS)

    Maeda, Takuto; Nishida, Kiwamu; Takagi, Ryota; Obara, Kazushige

    2016-04-01

    The high-sensitive seismograph network (Hi-net) operated by National Research Institute for Earth Science and Disaster Prevention (NIED) has about 800 stations with average separation of 20 km all over the Japanese archipelago. Although it is equipped with short-period seismometers, we also can observe long-period seismic wave up to 100 s in periods for significantly large earthquakes. In this case, we may treat long-period seismic waves as a 2D wavefield with station separations shorter than wavelength rather than individual traces at stations. In this study, we attempt to reconstruct 2D wavefield and obtain its propagation properties from seismic gradiometry (SG) method. The SG estimates the wave amplitude and its spatial derivative coefficients from discrete station record by the Taylor series approximation with an inverse problem. By using spatial derivatives in horizontal directions, we can obtain properties of propagating wave packet such as the arrival direction, slowness, geometrical spreading and radiation pattern. In addition, by using spatial derivatives together with free-surface boundary condition, we may decompose the vector elastic 2D wavefield estimated by the SG into divergence and rotation components. First, we applied the seismic gradiometry to a synthetic long-period (20-50 s) seismogram dataset computed by numerical simulation in realistic 3D medium at the Hi-net station layout as a feasibility test. We confirmed that the wave amplitude and its spatial derivatives are very well reproduced with average correlation coefficients higher than 0.99 in this period range. Applications to a real large earthquakes show that the amplitude and phase of the wavefield are well reconstructed with additional information of arrival direction and its slowness. The reconstructed wavefield contained a clear contrast in slowness between body and surface waves, regional non-great-circle-path wave propagation which may be attributed to scattering. Slowness

  16. SNL3dFace

    2007-07-20

    This software distribution contains MATLAB and C++ code to enable identity verification using 3D images that may or may not contain a texture component. The code is organized to support system performance testing and system capability demonstration through the proper configuration of the available user interface. Using specific algorithm parameters the face recognition system has been demonstrated to achieve a 96.6% verification rate (Pd) at 0.001 false alarm rate. The system computes robust facial featuresmore » of a 3D normalized face using Principal Component Analysis (PCA) and Fisher Linear Discriminant Analysis (FLDA). A 3D normalized face is obtained by alighning each face, represented by a set of XYZ coordinated, to a scaled reference face using the Iterative Closest Point (ICP) algorithm. The scaled reference face is then deformed to the input face using an iterative framework with parameters that control the deformed surface regulation an rate of deformation. A variety of options are available to control the information that is encoded by the PCA. Such options include the XYZ coordinates, the difference of each XYZ coordinates from the reference, the Z coordinate, the intensity/texture values, etc. In addition to PCA/FLDA feature projection this software supports feature matching to obtain similarity matrices for performance analysis. In addition, this software supports visualization of the STL, MRD, 2D normalized, and PCA synthetic representations in a 3D environment.« less

  17. Making Inexpensive 3-D Models

    ERIC Educational Resources Information Center

    Manos, Harry

    2016-01-01

    Visual aids are important to student learning, and they help make the teacher's job easier. Keeping with the "TPT" theme of "The Art, Craft, and Science of Physics Teaching," the purpose of this article is to show how teachers, lacking equipment and funds, can construct a durable 3-D model reference frame and a model gravity…

  18. SNL3dFace

    SciTech Connect

    Russ, Trina; Koch, Mark; Koudelka, Melissa; Peters, Ralph; Little, Charles; Boehnen, Chris; Peters, Tanya

    2007-07-20

    This software distribution contains MATLAB and C++ code to enable identity verification using 3D images that may or may not contain a texture component. The code is organized to support system performance testing and system capability demonstration through the proper configuration of the available user interface. Using specific algorithm parameters the face recognition system has been demonstrated to achieve a 96.6% verification rate (Pd) at 0.001 false alarm rate. The system computes robust facial features of a 3D normalized face using Principal Component Analysis (PCA) and Fisher Linear Discriminant Analysis (FLDA). A 3D normalized face is obtained by alighning each face, represented by a set of XYZ coordinated, to a scaled reference face using the Iterative Closest Point (ICP) algorithm. The scaled reference face is then deformed to the input face using an iterative framework with parameters that control the deformed surface regulation an rate of deformation. A variety of options are available to control the information that is encoded by the PCA. Such options include the XYZ coordinates, the difference of each XYZ coordinates from the reference, the Z coordinate, the intensity/texture values, etc. In addition to PCA/FLDA feature projection this software supports feature matching to obtain similarity matrices for performance analysis. In addition, this software supports visualization of the STL, MRD, 2D normalized, and PCA synthetic representations in a 3D environment.

  19. 3D Printing: Exploring Capabilities

    ERIC Educational Resources Information Center

    Samuels, Kyle; Flowers, Jim

    2015-01-01

    As 3D printers become more affordable, schools are using them in increasing numbers. They fit well with the emphasis on product design in technology and engineering education, allowing students to create high-fidelity physical models to see and test different iterations in their product designs. They may also help students to "think in three…

  20. TACO3D. 3-D Finite Element Heat Transfer Code

    SciTech Connect

    Mason, W.E.

    1992-03-04

    TACO3D is a three-dimensional, finite-element program for heat transfer analysis. An extension of the two-dimensional TACO program, it can perform linear and nonlinear analyses and can be used to solve either transient or steady-state problems. The program accepts time-dependent or temperature-dependent material properties, and materials may be isotropic or orthotropic. A variety of time-dependent and temperature-dependent boundary conditions and loadings are available including temperature, flux, convection, and radiation boundary conditions and internal heat generation. Additional specialized features treat enclosure radiation, bulk nodes, and master/slave internal surface conditions (e.g., contact resistance). Data input via a free-field format is provided. A user subprogram feature allows for any type of functional representation of any independent variable. A profile (bandwidth) minimization option is available. The code is limited to implicit time integration for transient solutions. TACO3D has no general mesh generation capability. Rows of evenly-spaced nodes and rows of sequential elements may be generated, but the program relies on separate mesh generators for complex zoning. TACO3D does not have the ability to calculate view factors internally. Graphical representation of data in the form of time history and spatial plots is provided through links to the POSTACO and GRAPE postprocessor codes.

  1. 3D ultrasonic ray tracing in AutoCAD®

    NASA Astrophysics Data System (ADS)

    Reilly, D.; Leggat, P.; McNab, A.

    2001-04-01

    To assist with the design and validation of testing procedures for NDT, add-on modules have been developed for AutoCAD® 2000. One of the modules computes and displays ultrasonic 3D ray tracing. Another determines paths between two points, for instance a probe and a target or two probes. The third module displays phased array operational modes and calculates element delays for phased array operation. The modules can be applied to simple or complex solid model components.

  2. Effects of morphology, diameter and periodic distance of the Ag nanoparticle periodic arrays on the enhancement of the plasmonic field absorption in the CdSe quantum dots

    NASA Astrophysics Data System (ADS)

    Kohnehpoushi, Saman; Eskandari, Mehdi; Ahmadi, Vahid; Yousefirad, Mansooreh; Nabavi, Elham

    2016-09-01

    In this work, the numerical calculations of plasmonic field absorption of Ag nanoparticles (Ag NPs) periodic arrays in the CdSe quantum dot (QD) film are investigated by the three-dimensional finite difference time domain (FDTD). Diameter (D), periodic distance (P), and morphology effects of Ag NPs are investigated on the improvement of the plasmonic field absorption in CdSe QD film. Results show that plasmonic field absorption in CdSe QD film is enhanced with reduction of D of Ag NPs until 5 nm and reduces thereafter. It is observed that with raising D of Ag NPs, optimum plasmonic field absorption in CdSe QD film is shifted toward the higher P. Moreover, with varying morphology of Ag NPs from spherical to cylindrical, cubic, ringing and pyramid, the plasmonic field absorption is considerably enhanced in CdSe QD film and position of quadrupole plasmon mode (QPPM) is shifted toward further wavelength. For cylindrical Ag NPs, the QPPM intensity increased with raising height (H) until 15 nm and reduces thereafter.

  3. Coexisting localized and extended optical Bloch states in a periodic deep wire array microcavity

    NASA Astrophysics Data System (ADS)

    Löchner, Franz J. F.; Mischok, Andreas; Brückner, Robert; Lyssenko, Vadim G.; Zakhidov, Alexander A.; Fröb, Hartmut; Leo, K.

    2015-09-01

    We embed periodic SiO2 wires in an organic microcavity, producing a rectangular potential by the different optical thicknesses of the active layer due to the additional SiO2 layer. By μ -photoluminescence spectroscopy, we observe the energy dispersion of the photons and obtain discrete localized below and extended Bloch states above the potential barrier, respectively, showing that electro-magnetic waves can behave like massive particles, such as electrons, in crystal lattices. We investigate the dependencies on wire width and period and use the Kronig-Penney model to describe the photon energy dispersion, including an "effective mass" of a photon propagating through a microcavity implying polarization splitting. We obtain excellent agreement between experiment, simulation and analytical calculation.

  4. Superhydrophobic PDMS surfaces with three-dimensional (3D) pattern-dependent controllable adhesion

    NASA Astrophysics Data System (ADS)

    Yong, Jiale; Yang, Qing; Chen, Feng; Zhang, Dongshi; Du, Guangqing; Bian, Hao; Si, Jinhai; Yun, Feng; Hou, Xun

    2014-01-01

    In this paper, we demonstrate an effective approach for the three-dimensional (3D) pattern-structured superhydrophobic PDMS surfaces with controllable adhesion by using femtosecond laser etching method. By combining different laser power with a multi-layered etching way, various 3D patterns can be fabricated (for example, convex triangle array, round pit array, cylindrical array, convex rhombus array and concave triangle-cone array). The as-prepared surfaces with 3D patterns show superhydrophobic character and water controllable adhesion that range from ultralow to ultrahigh by designing different 3D patterns, on which the sliding angle can be controlled from 1° to 90° (the water droplet is firmly pinned on the superhydrophobic surface without any movement at any tilted angles). The 3D pattern-dependent adhesive property is attributed to the different contact modes. This work will provide a facile and promising strategy for the adhesion adjustment on superhydrophobic surfaces.

  5. Optical 3D watermark based digital image watermarking for telemedicine

    NASA Astrophysics Data System (ADS)

    Li, Xiao Wei; Kim, Seok Tae

    2013-12-01

    Region of interest (ROI) of a medical image is an area including important diagnostic information and must be stored without any distortion. This algorithm for application of watermarking technique for non-ROI of the medical image preserving ROI. The paper presents a 3D watermark based medical image watermarking scheme. In this paper, a 3D watermark object is first decomposed into 2D elemental image array (EIA) by a lenslet array, and then the 2D elemental image array data is embedded into the host image. The watermark extraction process is an inverse process of embedding. The extracted EIA through the computational integral imaging reconstruction (CIIR) technique, the 3D watermark can be reconstructed. Because the EIA is composed of a number of elemental images possesses their own perspectives of a 3D watermark object. Even though the embedded watermark data badly damaged, the 3D virtual watermark can be successfully reconstructed. Furthermore, using CAT with various rule number parameters, it is possible to get many channels for embedding. So our method can recover the weak point having only one transform plane in traditional watermarking methods. The effectiveness of the proposed watermarking scheme is demonstrated with the aid of experimental results.

  6. Design and scheduling for periodic concurrent error detection and recovery in processor arrays

    NASA Technical Reports Server (NTRS)

    Wang, Yi-Min; Chung, Pi-Yu; Fuchs, W. Kent

    1992-01-01

    Periodic application of time-redundant error checking provides the trade-off between error detection latency and performance degradation. The goal is to achieve high error coverage while satisfying performance requirements. We derive the optimal scheduling of checking patterns in order to uniformly distribute the available checking capability and maximize the error coverage. Synchronous buffering designs using data forwarding and dynamic reconfiguration are described. Efficient single-cycle diagnosis is implemented by error pattern analysis and direct-mapped recovery cache. A rollback recovery scheme using start-up control for local recovery is also presented.

  7. Experimental Study of Electrothermal 3D Mixing using 3D microPIV

    NASA Astrophysics Data System (ADS)

    Kauffmann, Paul; Loire, Sophie; Meinhart, Carl; Mezic, Igor

    2012-11-01

    Mixing is a keystep which can greatly accelerate bio-reactions. For thirty years, dynamical system theory has predicted that chaotic mixing must involve at least 3 dimensions (either time dependent 2D flows or 3D flows). So far, 3D embedded chaotic mixing has been scarcely studied at microscale. In that regard, electrokinetics has emerged as an efficient embedded actuation to drive microflows. Physiological mediums can be driven by electrothermal flows generated by the interaction of an electric field with conductivity and permittivity gradients induced by Joule heating We present original electrothermal time dependant 3D (3D+1) mixing in microwells. The key point of our chaotic mixer is to generate overlapping asymmetric vortices, which switch periodically. When the two vortex configurations blink, flows stretch and fold, thereby generating chaotic advection. Each flow configuration is characterized by an original 3D PIV (3 Components / 3 Dimensions) based on the decomposition of the flows by Proper Orthogonal Decomposition. Velocity field distribution are then compared to COMSOL simulation and discussed. Mixing efficiency of low diffusive particles is studied using the mix-variance coefficient and shows a dramatic increase of mixing efficiency compared to steady flow.

  8. 3-D Relativistic MHD Simulations

    NASA Astrophysics Data System (ADS)

    Nishikawa, K.-I.; Frank, J.; Koide, S.; Sakai, J.-I.; Christodoulou, D. M.; Sol, H.; Mutel, R. L.

    1998-12-01

    We present 3-D numerical simulations of moderately hot, supersonic jets propagating initially along or obliquely to the field lines of a denser magnetized background medium with Lorentz factors of W = 4.56 and evolving in a four-dimensional spacetime. The new results are understood as follows: Relativistic simulations have consistently shown that these jets are effectively heavy and so they do not suffer substantial momentum losses and are not decelerated as efficiently as their nonrelativistic counterparts. In addition, the ambient magnetic field, however strong, can be pushed aside with relative ease by the beam, provided that the degrees of freedom associated with all three spatial dimensions are followed self-consistently in the simulations. This effect is analogous to pushing Japanese ``noren'' or vertical Venetian blinds out of the way while the slats are allowed to bend in 3-D space rather than as a 2-D slab structure.

  9. Forensic 3D Scene Reconstruction

    SciTech Connect

    LITTLE,CHARLES Q.; PETERS,RALPH R.; RIGDON,J. BRIAN; SMALL,DANIEL E.

    1999-10-12

    Traditionally law enforcement agencies have relied on basic measurement and imaging tools, such as tape measures and cameras, in recording a crime scene. A disadvantage of these methods is that they are slow and cumbersome. The development of a portable system that can rapidly record a crime scene with current camera imaging, 3D geometric surface maps, and contribute quantitative measurements such as accurate relative positioning of crime scene objects, would be an asset to law enforcement agents in collecting and recording significant forensic data. The purpose of this project is to develop a feasible prototype of a fast, accurate, 3D measurement and imaging system that would support law enforcement agents to quickly document and accurately record a crime scene.

  10. Forensic 3D scene reconstruction

    NASA Astrophysics Data System (ADS)

    Little, Charles Q.; Small, Daniel E.; Peters, Ralph R.; Rigdon, J. B.

    2000-05-01

    Traditionally law enforcement agencies have relied on basic measurement and imaging tools, such as tape measures and cameras, in recording a crime scene. A disadvantage of these methods is that they are slow and cumbersome. The development of a portable system that can rapidly record a crime scene with current camera imaging, 3D geometric surface maps, and contribute quantitative measurements such as accurate relative positioning of crime scene objects, would be an asset to law enforcement agents in collecting and recording significant forensic data. The purpose of this project is to develop a fieldable prototype of a fast, accurate, 3D measurement and imaging system that would support law enforcement agents to quickly document and accurately record a crime scene.

  11. 360-degree 3D profilometry

    NASA Astrophysics Data System (ADS)

    Song, Yuanhe; Zhao, Hong; Chen, Wenyi; Tan, Yushan

    1997-12-01

    A new method of 360 degree turning 3D shape measurement in which light sectioning and phase shifting techniques are both used is presented in this paper. A sine light field is applied in the projected light stripe, meanwhile phase shifting technique is used to calculate phases of the light slit. Thereafter wrapped phase distribution of the slit is formed and the unwrapping process is made by means of the height information based on the light sectioning method. Therefore phase measuring results with better precision can be obtained. At last the target 3D shape data can be produced according to geometric relationships between phases and the object heights. The principles of this method are discussed in detail and experimental results are shown in this paper.

  12. 3D Printable Graphene Composite.

    PubMed

    Wei, Xiaojun; Li, Dong; Jiang, Wei; Gu, Zheming; Wang, Xiaojuan; Zhang, Zengxing; Sun, Zhengzong

    2015-01-01

    In human being's history, both the Iron Age and Silicon Age thrived after a matured massive processing technology was developed. Graphene is the most recent superior material which could potentially initialize another new material Age. However, while being exploited to its full extent, conventional processing methods fail to provide a link to today's personalization tide. New technology should be ushered in. Three-dimensional (3D) printing fills the missing linkage between graphene materials and the digital mainstream. Their alliance could generate additional stream to push the graphene revolution into a new phase. Here we demonstrate for the first time, a graphene composite, with a graphene loading up to 5.6 wt%, can be 3D printable into computer-designed models. The composite's linear thermal coefficient is below 75 ppm·°C(-1) from room temperature to its glass transition temperature (Tg), which is crucial to build minute thermal stress during the printing process. PMID:26153673

  13. 3D Printed Robotic Hand

    NASA Technical Reports Server (NTRS)

    Pizarro, Yaritzmar Rosario; Schuler, Jason M.; Lippitt, Thomas C.

    2013-01-01

    Dexterous robotic hands are changing the way robots and humans interact and use common tools. Unfortunately, the complexity of the joints and actuations drive up the manufacturing cost. Some cutting edge and commercially available rapid prototyping machines now have the ability to print multiple materials and even combine these materials in the same job. A 3D model of a robotic hand was designed using Creo Parametric 2.0. Combining "hard" and "soft" materials, the model was printed on the Object Connex350 3D printer with the purpose of resembling as much as possible the human appearance and mobility of a real hand while needing no assembly. After printing the prototype, strings where installed as actuators to test mobility. Based on printing materials, the manufacturing cost of the hand was $167, significantly lower than other robotic hands without the actuators since they have more complex assembly processes.

  14. 3D light scanning macrography.

    PubMed

    Huber, D; Keller, M; Robert, D

    2001-08-01

    The technique of 3D light scanning macrography permits the non-invasive surface scanning of small specimens at magnifications up to 200x. Obviating both the problem of limited depth of field inherent to conventional close-up macrophotography and the metallic coating required by scanning electron microscopy, 3D light scanning macrography provides three-dimensional digital images of intact specimens without the loss of colour, texture and transparency information. This newly developed technique offers a versatile, portable and cost-efficient method for the non-invasive digital and photographic documentation of small objects. Computer controlled device operation and digital image acquisition facilitate fast and accurate quantitative morphometric investigations, and the technique offers a broad field of research and educational applications in biological, medical and materials sciences. PMID:11489078

  15. 3D-graphite structure

    SciTech Connect

    Belenkov, E. A. Ali-Pasha, V. A.

    2011-01-15

    The structure of clusters of some new carbon 3D-graphite phases have been calculated using the molecular-mechanics methods. It is established that 3D-graphite polytypes {alpha}{sub 1,1}, {alpha}{sub 1,3}, {alpha}{sub 1,5}, {alpha}{sub 2,1}, {alpha}{sub 2,3}, {alpha}{sub 3,1}, {beta}{sub 1,2}, {beta}{sub 1,4}, {beta}{sub 1,6}, {beta}{sub 2,1}, and {beta}{sub 3,2} consist of sp{sup 2}-hybridized atoms, have hexagonal unit cells, and differ in regards to the structure of layers and order of their alternation. A possible way to experimentally synthesize new carbon phases is proposed: the polymerization and carbonization of hydrocarbon molecules.

  16. [Real time 3D echocardiography].

    PubMed

    Bauer, F; Shiota, T; Thomas, J D

    2001-07-01

    Three-dimensional representation of the heart is an old concern. Usually, 3D reconstruction of the cardiac mass is made by successive acquisition of 2D sections, the spatial localisation and orientation of which require complex guiding systems. More recently, the concept of volumetric acquisition has been introduced. A matricial emitter-receiver probe complex with parallel data processing provides instantaneous of a pyramidal 64 degrees x 64 degrees volume. The image is restituted in real time and is composed of 3 planes (planes B and C) which can be displaced in all spatial directions at any time during acquisition. The flexibility of this system of acquisition allows volume and mass measurement with greater accuracy and reproducibility, limiting inter-observer variability. Free navigation of the planes of investigation allows reconstruction for qualitative and quantitative analysis of valvular heart disease and other pathologies. Although real time 3D echocardiography is ready for clinical usage, some improvements are still necessary to improve its conviviality. Then real time 3D echocardiography could be the essential tool for understanding, diagnosis and management of patients. PMID:11494630

  17. [Real time 3D echocardiography

    NASA Technical Reports Server (NTRS)

    Bauer, F.; Shiota, T.; Thomas, J. D.

    2001-01-01

    Three-dimensional representation of the heart is an old concern. Usually, 3D reconstruction of the cardiac mass is made by successive acquisition of 2D sections, the spatial localisation and orientation of which require complex guiding systems. More recently, the concept of volumetric acquisition has been introduced. A matricial emitter-receiver probe complex with parallel data processing provides instantaneous of a pyramidal 64 degrees x 64 degrees volume. The image is restituted in real time and is composed of 3 planes (planes B and C) which can be displaced in all spatial directions at any time during acquisition. The flexibility of this system of acquisition allows volume and mass measurement with greater accuracy and reproducibility, limiting inter-observer variability. Free navigation of the planes of investigation allows reconstruction for qualitative and quantitative analysis of valvular heart disease and other pathologies. Although real time 3D echocardiography is ready for clinical usage, some improvements are still necessary to improve its conviviality. Then real time 3D echocardiography could be the essential tool for understanding, diagnosis and management of patients.

  18. Long Period (LP) volcanic earthquake source location at Merapi volcano by using dense array technics

    NASA Astrophysics Data System (ADS)

    Metaxian, Jean Philippe; Budi Santoso, Agus; Laurin, Antoine; Subandriyo, Subandriyo; Widyoyudo, Wiku; Arshab, Ghofar

    2015-04-01

    Since 2010, Merapi shows unusual activity compared to last decades. Powerful phreatic explosions are observed; some of them are preceded by LP signals. In the literature, LP seismicity is thought to be originated within the fluid, and therefore to be representative of the pressurization state of the volcano plumbing system. Another model suggests that LP events are caused by slow, quasi-brittle, low stress-drop failure driven by transient upper-edifice deformations. Knowledge of the spatial distribution of LP events is fundamental for better understanding the physical processes occurring in the conduit, as well as for the monitoring and the improvement of eruption forecasting. LP events recorded at Merapi have a spectral content dominated by frequencies between 0.8 and 3 Hz. To locate the source of these events, we installed a seismic antenna composed of 4 broadband CMG-6TD Güralp stations. This network has an aperture of 300 m. It is located on the site of Pasarbubar, between 500 and 800 m from the crater rim. Two multi-parameter stations (seismic, tiltmeter, S-P) located in the same area, equipped with broadband CMG-40T Güralp sensors may also be used to complete the data of the antenna. The source of LP events is located by using different approaches. In the first one, we used a method based on the measurement of the time delays between the early beginnings of LP events for each array receiver. The observed differences of time delays obtained for each pair of receivers are compared to theoretical values calculated from the travel times computed between grid nodes, which are positioned in the structure, and each receiver. In a second approach, we estimate the slowness vector by using MUSIC algorithm applied to 3-components data. From the slowness vector, we deduce the back-azimuth and the incident angle, which give an estimation of LP source depth in the conduit. This work is part of the Domerapi project funded by French Agence Nationale de la Recherche (https

  19. 3D-Printed Biodegradable Polymeric Vascular Grafts.

    PubMed

    Melchiorri, Anthony J; Hibino, Narutoshi; Best, C A; Yi, T; Lee, Y U; Kraynak, C A; Kimerer, Lucas K; Krieger, A; Kim, P; Breuer, Christopher K; Fisher, John P

    2016-02-01

    Congenital heart defect interventions may benefit from the fabrication of patient-specific vascular grafts because of the wide array of anatomies present in children with cardiovascular defects. 3D printing is used to establish a platform for the production of custom vascular grafts, which are biodegradable, mechanically compatible with vascular tissues, and support neotissue formation and growth. PMID:26627057

  20. 3-D Television Without Glasses: On Standard Bandwidth

    NASA Astrophysics Data System (ADS)

    Collender, Robert B.

    1983-10-01

    This system for stereoscopic television uses relative camera to scene translating motion and does not require optical aids at the observer's eyes, presents a horizontal parallax (hologram like) 3-D full motion scene to a wide audience, has no dead zones or pseudo 3-D zones over the entire horizontal viewing field and operates on standard telecast signals requiring no changes to the television studio equipment or the home television antenna. The only change required at the receiving end is a special television projector. The system is compatible with pre-recorded standard color television signals. The cathode ray tube is eliminated by substituting an array of solid state charge couple device liquid crystal light valves which have the property to receive television fields in parallel from memory and which are arrayed in an arc for scanning purposes. The array contains a scrolled sequence of successive television frames which serve as the basis for 3-D horizontal viewing parallax. These light valves reflect polarized light with the degree of polarization made a function of the scene brightness. The array is optically scanned and the sequence rapidly projected onto a cylindrical concaved semi-specular screen that returns all of the light to a rapidly translating vertical "aerial" exit slit of light through which the audience views the reconstructed 3-D scene.

  1. A simple and rapid 3D view method for selective and sensitive determination of paclitaxel in micro volume rat plasma by LC-diode array UV and its application to a pharmacokinetic study.

    PubMed

    Kumar, Sekar Vasantha; Srinath, Selladurai; Saha, Ranendra N

    2012-03-01

    A simple, highly repeatable and reproducible method for the estimation of Paclitaxel (TAX) in micro volume amounts of rat plasma is successfully developed and validated. The extraction procedure using 800 µL of ice-cold acetonitrile is very simple and economical with high sensitivity. The rectangular ratiograms and purity curve demonstrate the selectivity of the method. The validation and stability results show that propylparaben (PP) is a suitable internal standard (resolution 7.70 ± 0.15 min) for the estimation of TAX in micro volume rat plasma. TAX and PP are separated by isocratic reversed-phase high-performance liquid chromatography with diode array UV method with a retention time of 8.0 ± 0.25 and 5.3 ± 0.15 min, respectively, with a total run time of 10 min. The system suitability results show that the method has good reproducibility. The stability of TAX is well studied in rat plasma, and the % RSD of all stability studies of TAX are well within the acceptable range of ± 20 % at the lower limit of quantitation (LLOQ) and ± 15% at all quality control levels. The limit of detection (LOD) and LLOQ of the method are 5 and 10 ng/mL, respectively. This rapid method is successfully used to study the i.v pharmacokinetic of TAX at 10 mg/kg in wistar rats, and drug concentration is detected up to 24 h. PMID:22337803

  2. GPU-Accelerated Denoising in 3D (GD3D)

    2013-10-01

    The raw computational power GPU Accelerators enables fast denoising of 3D MR images using bilateral filtering, anisotropic diffusion, and non-local means. This software addresses two facets of this promising application: what tuning is necessary to achieve optimal performance on a modern GPU? And what parameters yield the best denoising results in practice? To answer the first question, the software performs an autotuning step to empirically determine optimal memory blocking on the GPU. To answer themore » second, it performs a sweep of algorithm parameters to determine the combination that best reduces the mean squared error relative to a noiseless reference image.« less

  3. A tunable acoustic barrier based on periodic arrays of subwavelength slits

    NASA Astrophysics Data System (ADS)

    Rubio, Constanza; Uris, Antonio; Candelas, Pilar; Belmar, Francisco; Gomez-Lozano, Vicente

    2015-05-01

    The most usual method to reduce undesirable enviromental noise levels during its transmission is the use of acoustic barriers. A novel type of acoustic barrier based on sound transmission through subwavelength slits is presented. This system consists of two rows of periodic repetition of vertical rigid pickets separated by a slit of subwavelength width and with a misalignment between them. Here, both the experimental and the numerical analyses are presented. The acoustic barrier proposed can be easily built and is frequency tunable. The results demonstrated that the proposed barrier can be tuned to mitigate a band noise without excesive barrier thickness. The use of this system as an environmental acoustic barrier has certain advantages with regard to the ones currently used both from the constructive and the acoustical point of view.

  4. How diffraction limits ultrasonic screening in phononic plate composed of a periodic array of resonant slits

    NASA Astrophysics Data System (ADS)

    Elayouch, Aliyasin; Addouche, Mahmoud; Lasaygues, Philippe; Achaoui, Younes; Ouisse, Morvan; Khelif, Abdelkrim

    2016-05-01

    We explore experimentally the role played by diffraction in the phenomenon of acoustic shielding provided by a plate that is periodically perforated with subwavelength slits and immersed in water. We carried out ultrasonic transmission measurements for all directions of propagation in order to check the omnidirectionality of acoustic shielding. While a single slit acts as a Fabry-Perot resonator in the frequency range of interest, the coupling between adjacent slits provides an attenuation frequency band centered around the resonant frequency that is mostly independent of the angle of incidence. Beyond the incident angle of 45 degrees, however, we observe the appearance of scattered radiation that limits the attenuation of ultrasound. This spurious scattering is shown to arise from diffraction by the grating of slits. xml:lang="fr"

  5. Scattering from an infinite array of periodic broken wires buried in a dielectric sheet

    NASA Astrophysics Data System (ADS)

    Gallagher, J. G.; Brammer, D. J.

    1985-02-01

    The scattering of a plane wave from a periodic broken-wire grid buried in a dielectric sheet is studied for a general angle of incidence and for arbitrary linear polarization. The scattered field is expanded in a set of Floquet modes, and the modal coefficients are obtained through the current expansion for a reflecting antenna. The general formulation of the problem is applicable for grids in an infinite dielectric and when located at the boundary interface of two dielectrics. A moment method is used to determine the current on the grid elements and numerical results for the transmission characteristics of several different grid configurations are presented. In addition, the effect on the resonant frequency of parametric variations in the grid geometry is determined. Predicted results are compared with measured transmission characteristics and show excellent agreement.

  6. Effective Spring Stiffness for a Planar Periodic Array of Collinear Cracks at an Interface between Two Dissimilar Isotropic Materials

    PubMed Central

    Lekesiz, Huseyin; Katsube, Noriko; Rokhlin, Stanislav I.; Seghi, Robert R.

    2011-01-01

    Explicit analytical expressions are obtained for the longitudinal and transverse effective spring stiffnesses of a planar periodic array of collinear cracks at the interface between two dissimilar isotropic materials; they are shown to be identical in a general case of elastic dissimilarity (the well-known open interface crack model is employed for the solution). Since the interfacial spring stiffness can be experimentally determined from ultrasound reflection and transmission analysis, the proposed expressions can be useful in estimating the percentage of disbond area between two dissimilar materials, which is directly related to the residual strength of the interface. The effects of elastic dissimilarity, crack density and crack interaction on the effective spring stiffness are clearly represented in the solution. It is shown that in general the crack interaction weakly depends on material dissimilarity and, for most practical cases, the crack interaction is nearly the same as that for crack arrays between identical solids. This allows approximate factorization of the effective spring stiffness for an array of cracks between dissimilar materials in terms of an elastic dissimilarity factor and two factors obtained for cracks in a homogeneous material: the effective spring stiffness for non-interacting (independent) cracks and the crack interaction factor. In order to avoid the effect of the crack surface interpenetration zones on the effective spring stiffness, the range of the tensile to transverse load ratios is obtained under the assumption of small-scale contact conditions. Since real cracks are often slightly open (due to prior loading history and plastic deformation), it is demonstrated that for ultrasound applications the results obtained are valid for most practical cases of small interfacial cracks as long as the mid-crack opening normalized by the crack length is at least in the order of 10−5. PMID:23710104

  7. Magmatic Systems in 3-D

    NASA Astrophysics Data System (ADS)

    Kent, G. M.; Harding, A. J.; Babcock, J. M.; Orcutt, J. A.; Bazin, S.; Singh, S.; Detrick, R. S.; Canales, J. P.; Carbotte, S. M.; Diebold, J.

    2002-12-01

    Multichannel seismic (MCS) images of crustal magma chambers are ideal targets for advanced visualization techniques. In the mid-ocean ridge environment, reflections originating at the melt-lens are well separated from other reflection boundaries, such as the seafloor, layer 2A and Moho, which enables the effective use of transparency filters. 3-D visualization of seismic reflectivity falls into two broad categories: volume and surface rendering. Volumetric-based visualization is an extremely powerful approach for the rapid exploration of very dense 3-D datasets. These 3-D datasets are divided into volume elements or voxels, which are individually color coded depending on the assigned datum value; the user can define an opacity filter to reject plotting certain voxels. This transparency allows the user to peer into the data volume, enabling an easy identification of patterns or relationships that might have geologic merit. Multiple image volumes can be co-registered to look at correlations between two different data types (e.g., amplitude variation with offsets studies), in a manner analogous to draping attributes onto a surface. In contrast, surface visualization of seismic reflectivity usually involves producing "fence" diagrams of 2-D seismic profiles that are complemented with seafloor topography, along with point class data, draped lines and vectors (e.g. fault scarps, earthquake locations and plate-motions). The overlying seafloor can be made partially transparent or see-through, enabling 3-D correlations between seafloor structure and seismic reflectivity. Exploration of 3-D datasets requires additional thought when constructing and manipulating these complex objects. As numbers of visual objects grow in a particular scene, there is a tendency to mask overlapping objects; this clutter can be managed through the effective use of total or partial transparency (i.e., alpha-channel). In this way, the co-variation between different datasets can be investigated

  8. Single-step optical realization of bio-inspired dual-periodic motheye and gradient-index-array photonic structures.

    PubMed

    Behera, Saraswati; Joseph, Joby

    2016-08-01

    This Letter demonstrates a single-step optical realization method for hexagonal and square lattice-based dual periodic motheye and gradient-index-array photonic structures over large areas. Computed phase mask of gradient interference patterns are used as inputs to a phase-only spatial light modulator (SLM), and the first-order diffracting beams are coherently superposed with the help of a 2f-2f Fourier filtering setup to avoid complex optical geometry for generation and control of individual beams. The simulated interference patterns are verified experimentally through a CMOS camera. The fabricated micro-structures on a positive photoresist are shown to have a major periodicity of 638 μm and minor periodicity of 25.2 μm, with the air hole diameter varying from 22.7 to 6.9 μm along the X and Y axes. The depth of the fabricated structure gradually varies from 4.203 μm at the center to 1.818 μm at the corner. These structures may be scaled down to submicron features that can show improved anti-reflection properties for solar energy harvesting and GRIN lens for optical wavelength region. PMID:27472623

  9. Lateral arrays of vertical ZnO nanowalls on a periodically polarity-inverted ZnO template.

    PubMed

    Lee, Sang Hyun; Minegishi, Tsutomu; Ha, Jun-Seok; Park, Jin-sub; Lee, Hyo-Jong; Lee, Hyun Jung; Shiku, Hitoshi; Matsue, Tomokazu; Hong, Soon-Ku; Jeon, Heonsu; Yao, Takafumi

    2009-06-10

    Well aligned ZnO nanowall arrays with submicron pitch were grown on a periodically polarity-inverted ZnO template using a carbothermal reduction process. Under the conditions of a highly dense Au catalyst for increasing nucleation sites, ZnO nanowalls with a thickness of 126 +/- 10 nm, an average height of 3.4 microm, and a length of about 10 mm were formed on the template. The nanowalls were only grown on a Zn-polar surface due to a different growth mode with an O-polar surface. The results of x-ray diffraction and photoluminescence (PL) measurements revealed a single crystalline, vertical alignment on the template, and a large surface to volume ratio of the ZnO nanowalls. PMID:19448285

  10. Multi-function all optical packet switch by periodic wavelength arrangement in an arrayed waveguide grating and wideband optical filters.

    PubMed

    Feng, Kai-Ming; Wu, Chung-Yu; Wen, Yu-Hsiang

    2012-01-16

    By utilizing the cyclic filtering function of an NxN arrayed waveguide grating (AWG), we propose and experimentally demonstrate a novel multi-function all optical packet switching (OPS) architecture by applying a periodical wavelength arrangement between the AWG in the optical routing/buffering unit and a set of wideband optical filters in the switched output ports to achieve the desired routing and buffering functions. The proposed OPS employs only one tunable wavelength converter at the input port to convert the input wavelength to a designated wavelength which reduces the number of active optical components and thus the complexity of the traffic control is simplified in the OPS. With the proposed OPS architecture, multiple optical packet switching functions, including arbitrary packet switching and buffering, first-in-first-out (FIFO) packet multiplexing, packet demultiplexing and packet add/drop multiplexing, have been successfully demonstrated. PMID:22274416

  11. Full-Waveform Validation of a 3D Seismic Model for Western US

    NASA Astrophysics Data System (ADS)

    Maceira, M.; Larmat, C. S.; Ammon, C. J.; Chai, C.; Herrmann, R. B.

    2014-12-01

    Since the initiation of tomographic studies in the 1970s, geoscientists have advanced the art of inferring 3D variations in the subsurface using collections of geophysical (primarily seismic) observables recorded at or near Earth's surface. Advances have come from improvement and enhancement of the available data and from research on theoretical and computational improvements to tomographic and generalized inverse methods. In the last decade, utilizing dense array datasets, these efforts have led to unprecedented 3D images of the subsurface. Understandably, less effort has been expended on model validation to provide an absolute assessment of model uncertainty. Generally models constructed with different data sets and independent computational codes are assessed with geological reasonability and compared other models to gain confidence. The question of "How good is a particular 3D geophysical model at representing the Earth's true nature?" remains largely unaddressed at a time when 3D Earth models are used for both societal and energy security. In the last few years, opportunities have arisen in earth-structure imaging, including the advent of new methods in computational seismology and statistical sciences. We use the unique and extensive High Performance Computing resources available at Los Alamos National Laboratory to explore approaches to realistic model validation. We present results from a study focused on validating a 3D model for the western United States generated using a joint inversion simultaneously fitting interpolated teleseismic P-wave receiver functions, Rayleigh-wave group-velocity estimates between 7 and 250 s period, and high-wavenumber filtered Bouguer gravity observations. Validation of the obtained model is performed through systematic comparison of observed and predicted seismograms generated using the Spectral Element Method, which is a direct numerical solution for full waveform modeling in 3D models, with accuracy of spectral methods.

  12. Broadband attenuation of Lamb waves through a periodic array of thin rectangular junctions

    NASA Astrophysics Data System (ADS)

    Moiseyenko, Rayisa P.; Pennec, Yan; Marchal, Rémi; Bonello, Bernard; Djafari-Rouhani, Bahram

    2014-10-01

    We study theoretically subwavelength physical phenomena, such as resonant transmission and broadband sound shielding for Lamb waves propagating in an acoustic metamaterial made of a thin plate drilled with one or two row(s) of rectangular holes. The resonances and antiresonances of periodically arranged rectangular junctions separated by holes are investigated as a function of the geometrical parameters of the junctions. With one and two row(s) of holes, high frequency specific features in the transmission coefficient are explained in terms of a coupling of incident waves with both Fabry-Perot oscillations inside the junctions and induced surface acoustic waves between the homogeneous part of the plate and the row of holes. With two rows of holes, low frequency peaks and dips appear in the transmission spectrum. The choice of the distance between the two rows of holes allows the realization of a broadband low frequency acoustic shielding with attenuation over 99% for symmetric waves in a wide low frequency range and over 90% for antisymmetric ones. The origin of the transmission gap is discussed in terms of localized modes of the "H" element made by the junctions, connecting the two homogeneous parts of the plate.

  13. Fully 3D refraction correction dosimetry system

    NASA Astrophysics Data System (ADS)

    Manjappa, Rakesh; Sharath Makki, S.; Kumar, Rajesh; Mohan Vasu, Ram; Kanhirodan, Rajan

    2016-02-01

    The irradiation of selective regions in a polymer gel dosimeter results in an increase in optical density and refractive index (RI) at those regions. An optical tomography-based dosimeter depends on rayline path through the dosimeter to estimate and reconstruct the dose distribution. The refraction of light passing through a dose region results in artefacts in the reconstructed images. These refraction errors are dependant on the scanning geometry and collection optics. We developed a fully 3D image reconstruction algorithm, algebraic reconstruction technique-refraction correction (ART-rc) that corrects for the refractive index mismatches present in a gel dosimeter scanner not only at the boundary, but also for any rayline refraction due to multiple dose regions inside the dosimeter. In this study, simulation and experimental studies have been carried out to reconstruct a 3D dose volume using 2D CCD measurements taken for various views. The study also focuses on the effectiveness of using different refractive-index matching media surrounding the gel dosimeter. Since the optical density is assumed to be low for a dosimeter, the filtered backprojection is routinely used for reconstruction. We carry out the reconstructions using conventional algebraic reconstruction (ART) and refractive index corrected ART (ART-rc) algorithms. The reconstructions based on FDK algorithm for cone-beam tomography has also been carried out for comparison. Line scanners and point detectors, are used to obtain reconstructions plane by plane. The rays passing through dose region with a RI mismatch does not reach the detector in the same plane depending on the angle of incidence and RI. In the fully 3D scanning setup using 2D array detectors, light rays that undergo refraction are still collected and hence can still be accounted for in the reconstruction algorithm. It is found that, for the central region of the dosimeter, the usable radius using ART-rc algorithm with water as RI matched

  14. Fully 3D refraction correction dosimetry system.

    PubMed

    Manjappa, Rakesh; Makki, S Sharath; Kumar, Rajesh; Vasu, Ram Mohan; Kanhirodan, Rajan

    2016-02-21

    The irradiation of selective regions in a polymer gel dosimeter results in an increase in optical density and refractive index (RI) at those regions. An optical tomography-based dosimeter depends on rayline path through the dosimeter to estimate and reconstruct the dose distribution. The refraction of light passing through a dose region results in artefacts in the reconstructed images. These refraction errors are dependant on the scanning geometry and collection optics. We developed a fully 3D image reconstruction algorithm, algebraic reconstruction technique-refraction correction (ART-rc) that corrects for the refractive index mismatches present in a gel dosimeter scanner not only at the boundary, but also for any rayline refraction due to multiple dose regions inside the dosimeter. In this study, simulation and experimental studies have been carried out to reconstruct a 3D dose volume using 2D CCD measurements taken for various views. The study also focuses on the effectiveness of using different refractive-index matching media surrounding the gel dosimeter. Since the optical density is assumed to be low for a dosimeter, the filtered backprojection is routinely used for reconstruction. We carry out the reconstructions using conventional algebraic reconstruction (ART) and refractive index corrected ART (ART-rc) algorithms. The reconstructions based on FDK algorithm for cone-beam tomography has also been carried out for comparison. Line scanners and point detectors, are used to obtain reconstructions plane by plane. The rays passing through dose region with a RI mismatch does not reach the detector in the same plane depending on the angle of incidence and RI. In the fully 3D scanning setup using 2D array detectors, light rays that undergo refraction are still collected and hence can still be accounted for in the reconstruction algorithm. It is found that, for the central region of the dosimeter, the usable radius using ART-rc algorithm with water as RI matched

  15. Characterizing targets and backgrounds for 3D laser radars

    NASA Astrophysics Data System (ADS)

    Steinvall, Ove K.; Larsson, Hakan; Gustafsson, Frank; Chevalier, Tomas R.; Persson, Asa; Klasen, Lena M.

    2004-12-01

    Exciting development is taking place in 3 D sensing laser radars. Scanning systems are well established for mapping from airborne and ground sensors. 3 D sensing focal plane arrays (FPAs) enable a full range and intensity image can be captured in one laser shot. Gated viewing systems also produces 3 D target information. Many applications for 3 D laser radars are found in robotics, rapid terrain visualization, augmented vision, reconnaissance and target recognition, weapon guidance including aim point selection and others. The net centric warfare will demand high resolution geo-data for a common description of the environment. At FOI we have a measurement program to collect data relevant for 3 D laser radars using airborne and tripod mounted equipment for data collection. Data collection spans from single pixel waveform collection (1 D) over 2 D using range gated imaging to full 3 D imaging using scanning systems. This paper will describe 3 D laser data from different campaigns with emphasis on range distribution and reflections properties for targets and background during different seasonal conditions. Example of the use of the data for system modeling, performance prediction and algorithm development will be given. Different metrics to characterize the data set will also be discussed.

  16. Interactive 3D Mars Visualization

    NASA Technical Reports Server (NTRS)

    Powell, Mark W.

    2012-01-01

    The Interactive 3D Mars Visualization system provides high-performance, immersive visualization of satellite and surface vehicle imagery of Mars. The software can be used in mission operations to provide the most accurate position information for the Mars rovers to date. When integrated into the mission data pipeline, this system allows mission planners to view the location of the rover on Mars to 0.01-meter accuracy with respect to satellite imagery, with dynamic updates to incorporate the latest position information. Given this information so early in the planning process, rover drivers are able to plan more accurate drive activities for the rover than ever before, increasing the execution of science activities significantly. Scientifically, this 3D mapping information puts all of the science analyses to date into geologic context on a daily basis instead of weeks or months, as was the norm prior to this contribution. This allows the science planners to judge the efficacy of their previously executed science observations much more efficiently, and achieve greater science return as a result. The Interactive 3D Mars surface view is a Mars terrain browsing software interface that encompasses the entire region of exploration for a Mars surface exploration mission. The view is interactive, allowing the user to pan in any direction by clicking and dragging, or to zoom in or out by scrolling the mouse or touchpad. This set currently includes tools for selecting a point of interest, and a ruler tool for displaying the distance between and positions of two points of interest. The mapping information can be harvested and shared through ubiquitous online mapping tools like Google Mars, NASA WorldWind, and Worldwide Telescope.

  17. A Clean Adirondack (3-D)

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This is a 3-D anaglyph showing a microscopic image taken of an area measuring 3 centimeters (1.2 inches) across on the rock called Adirondack. The image was taken at Gusev Crater on the 33rd day of the Mars Exploration Rover Spirit's journey (Feb. 5, 2004), after the rover used its rock abrasion tool brush to clean the surface of the rock. Dust, which was pushed off to the side during cleaning, can still be seen to the left and in low areas of the rock.

  18. Making Inexpensive 3-D Models

    NASA Astrophysics Data System (ADS)

    Manos, Harry

    2016-03-01

    Visual aids are important to student learning, and they help make the teacher's job easier. Keeping with the TPT theme of "The Art, Craft, and Science of Physics Teaching," the purpose of this article is to show how teachers, lacking equipment and funds, can construct a durable 3-D model reference frame and a model gravity well tailored to specific class lessons. Most of the supplies are readily available in the home or at school: rubbing alcohol, a rag, two colors of spray paint, art brushes, and masking tape. The cost of these supplies, if you don't have them, is less than 20.

  19. What Lies Ahead (3-D)

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This 3-D cylindrical-perspective mosaic taken by the navigation camera on the Mars Exploration Rover Spirit on sol 82 shows the view south of the large crater dubbed 'Bonneville.' The rover will travel toward the Columbia Hills, seen here at the upper left. The rock dubbed 'Mazatzal' and the hole the rover drilled in to it can be seen at the lower left. The rover's position is referred to as 'Site 22, Position 32.' This image was geometrically corrected to make the horizon appear flat.

  20. Vacant Lander in 3-D

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This 3-D image captured by the Mars Exploration Rover Opportunity's rear hazard-identification camera shows the now-empty lander that carried the rover 283 million miles to Meridiani Planum, Mars. Engineers received confirmation that Opportunity's six wheels successfully rolled off the lander and onto martian soil at 3:01 a.m. PST, January 31, 2004, on the seventh martian day, or sol, of the mission. The rover is approximately 1 meter (3 feet) in front of the lander, facing north.

  1. Positional Awareness Map 3D (PAM3D)

    NASA Technical Reports Server (NTRS)

    Hoffman, Monica; Allen, Earl L.; Yount, John W.; Norcross, April Louise

    2012-01-01

    The Western Aeronautical Test Range of the National Aeronautics and Space Administration s Dryden Flight Research Center needed to address the aging software and hardware of its current situational awareness display application, the Global Real-Time Interactive Map (GRIM). GRIM was initially developed in the late 1980s and executes on older PC architectures using a Linux operating system that is no longer supported. Additionally, the software is difficult to maintain due to its complexity and loss of developer knowledge. It was decided that a replacement application must be developed or acquired in the near future. The replacement must provide the functionality of the original system, the ability to monitor test flight vehicles in real-time, and add improvements such as high resolution imagery and true 3-dimensional capability. This paper will discuss the process of determining the best approach to replace GRIM, and the functionality and capabilities of the first release of the Positional Awareness Map 3D.

  2. 3D Printable Graphene Composite

    NASA Astrophysics Data System (ADS)

    Wei, Xiaojun; Li, Dong; Jiang, Wei; Gu, Zheming; Wang, Xiaojuan; Zhang, Zengxing; Sun, Zhengzong

    2015-07-01

    In human being’s history, both the Iron Age and Silicon Age thrived after a matured massive processing technology was developed. Graphene is the most recent superior material which could potentially initialize another new material Age. However, while being exploited to its full extent, conventional processing methods fail to provide a link to today’s personalization tide. New technology should be ushered in. Three-dimensional (3D) printing fills the missing linkage between graphene materials and the digital mainstream. Their alliance could generate additional stream to push the graphene revolution into a new phase. Here we demonstrate for the first time, a graphene composite, with a graphene loading up to 5.6 wt%, can be 3D printable into computer-designed models. The composite’s linear thermal coefficient is below 75 ppm·°C-1 from room temperature to its glass transition temperature (Tg), which is crucial to build minute thermal stress during the printing process.

  3. 3D acoustic atmospheric tomography

    NASA Astrophysics Data System (ADS)

    Rogers, Kevin; Finn, Anthony

    2014-10-01

    This paper presents a method for tomographically reconstructing spatially varying 3D atmospheric temperature profiles and wind velocity fields based. Measurements of the acoustic signature measured onboard a small Unmanned Aerial Vehicle (UAV) are compared to ground-based observations of the same signals. The frequency-shifted signal variations are then used to estimate the acoustic propagation delay between the UAV and the ground microphones, which are also affected by atmospheric temperature and wind speed vectors along each sound ray path. The wind and temperature profiles are modelled as the weighted sum of Radial Basis Functions (RBFs), which also allow local meteorological measurements made at the UAV and ground receivers to supplement any acoustic observations. Tomography is used to provide a full 3D reconstruction/visualisation of the observed atmosphere. The technique offers observational mobility under direct user control and the capacity to monitor hazardous atmospheric environments, otherwise not justifiable on the basis of cost or risk. This paper summarises the tomographic technique and reports on the results of simulations and initial field trials. The technique has practical applications for atmospheric research, sound propagation studies, boundary layer meteorology, air pollution measurements, analysis of wind shear, and wind farm surveys.

  4. 3D Printed Bionic Ears

    PubMed Central

    Mannoor, Manu S.; Jiang, Ziwen; James, Teena; Kong, Yong Lin; Malatesta, Karen A.; Soboyejo, Winston O.; Verma, Naveen; Gracias, David H.; McAlpine, Michael C.

    2013-01-01

    The ability to three-dimensionally interweave biological tissue with functional electronics could enable the creation of bionic organs possessing enhanced functionalities over their human counterparts. Conventional electronic devices are inherently two-dimensional, preventing seamless multidimensional integration with synthetic biology, as the processes and materials are very different. Here, we present a novel strategy for overcoming these difficulties via additive manufacturing of biological cells with structural and nanoparticle derived electronic elements. As a proof of concept, we generated a bionic ear via 3D printing of a cell-seeded hydrogel matrix in the precise anatomic geometry of a human ear, along with an intertwined conducting polymer consisting of infused silver nanoparticles. This allowed for in vitro culturing of cartilage tissue around an inductive coil antenna in the ear, which subsequently enables readout of inductively-coupled signals from cochlea-shaped electrodes. The printed ear exhibits enhanced auditory sensing for radio frequency reception, and complementary left and right ears can listen to stereo audio music. Overall, our approach suggests a means to intricately merge biologic and nanoelectronic functionalities via 3D printing. PMID:23635097

  5. 3-D Relativistic MHD Simulations

    NASA Astrophysics Data System (ADS)

    Nishikaw, K.-I.; Frank, J.; Christodoulou, D. M.; Koide, S.; Sakai, J.-I.; Sol, H.; Mutel, R. L.

    1998-12-01

    We present 3-D numerical simulations of moderately hot, supersonic jets propagating initially along or obliquely to the field lines of a denser magnetized background medium with Lorentz factors of W=4.56 and evolving in a four-dimensional spacetime. The new results are understood as follows: Relativistic simulations have consistently shown that these jets are effectively heavy and so they do not suffer substantial momentum losses and are not decelerated as efficiently as their nonrelativistic counterparts. In addition, the ambient magnetic field, however strong, can be pushed aside with relative ease by the beam, provided that the degrees of freedom associated with all three spatial dimensions are followed self-consistently in the simulations. This effect is analogous to pushing Japanese ``noren'' or vertical Venetian blinds out of the way while the slats are allowed to bend in 3-D space rather than as a 2-D slab structure. We also simulate jets with the more realistic initial conditions for injecting jets for helical mangetic field, perturbed density, velocity, and internal energy, which are supposed to be caused in the process of jet generation. Three possible explanations for the observed variability are (i) tidal disruption of a star falling into the black hole, (ii) instabilities in the relativistic accretion disk, and (iii) jet-related PRocesses. New results will be reported at the meeting.

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