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Sample records for beam filling pattern

  1. Suppression of Beam-Ion Instability in Electron Rings with Multi-Bunch Train Beam Fillings

    SciTech Connect

    Wang, L.; Cai, Y.; Raubenheimer, T.O.; Fukuma, H.; /KEK, Tsukuba

    2011-08-18

    The ion-caused beam instability in the future light sources and electron damping rings can be serious due to the high beam current and ultra-small emittance of picometer level. One simple and effective mitigation of the instability is a multi-bunch train beam filling pattern which can significantly reduce the ion density near the beam, and therefore reduce the instability growth rate up to two orders of magnitude. The suppression is more effective for high intensity beams with low emittance. The distribution and the field of trapped ions are benchmarked to validate the model used in the paper. The wake field of ion-cloud and the beam-ion instability is investigated both analytically and numerically. We derived a simple formula for the build-up of ion-cloud and instability growth rate with the multi-bunch-train filling pattern. The ion instabilities in ILC damping ring, SuperKEKB and SPEAR3 are used to compare with our analyses. The analyses in this paper agree well with simulations.

  2. Gas Filled RF Resonator Hadron Beam Monitor for Intense Neutrino Beam Experiments

    SciTech Connect

    Yonehara, Katsuya; Abrams, Robert; Dinkel, Holly; Freemire, Ben; Johnson, Rolland; Kazakevich, Grigory; Tollestrup, Alvin; Zwaska, Robert

    2016-06-01

    MW-class beam facilities are being considered all over the world to produce an intense neutrino beam for fundamental particle physics experiments. A radiation-robust beam monitor system is required to diagnose the primary and secondary beam qualities in high-radiation environments. We have proposed a novel gas-filled RF-resonator hadron beam monitor in which charged particles passing through the resonator produce ionized plasma that changes the permittivity of the gas. The sensitivity of the monitor has been evaluated in numerical simulation. A signal manipulation algorithm has been designed. A prototype system will be constructed and tested by using a proton beam at the MuCool Test Area at Fermilab.

  3. Small tritium filling and monitoring apparatus for particle beam inertial confinement fusion targets.

    PubMed

    Chang, J; Leeper, R J; Martinez, C; McMurtry, W M

    1980-03-01

    A small gas filling apparatus has been developed to fill a particle beam ICF target with D-T gas mixture seconds before the target is irradiated. Included in the filling apparatus is a novel miniature pressure monitor which determines quantitatively the fill pressure by counting the rate of Beta particles emitted by the decaying tritium atoms.

  4. Dynamics of Elastic Beams with Embedded Fluid-Filled Parallel-Channel Networks

    PubMed Central

    Gat, Amir D.

    2015-01-01

    Abstract A pressurized fluid-filled parallel-channel network embedded in an elastic beam, asymmetrically to the neutral plane, will create a deformation field within the beam. Deformation due to embedded fluidic networks is currently studied in the context of soft actuators and soft-robotic applications. Expanding on this concept, configurations can be designed so that the pressure in the channel network is created directly from external forces acting on the beam, and thus can be viewed as passive solid–fluid composite structures. We approximate the deformation of such structures and relate the fluid pressure and geometry of the network to a continuous deformation-field function. This enables the design of networks creating steady arbitrary deformation fields as well as to eliminate deformation created by external time-varying forces, thus increasing the effective rigidity of the beam. In addition, by including the effects of the deformation created by the channel network on the beam inertia, we can modify the response of the beam to external time-varying forces. We present a scheme to design channel networks that create predefined oscillating deformation patterns in response to external oscillating forces. The ability to include inertial effects is relevant to the design of dynamic soft robots and soft actuators. Our results are illustrated and validated by numerical computations. PMID:27625914

  5. Salt tectonics, patterns of basin fill, and reservoir distribution

    SciTech Connect

    Yorston, H.J.; Miles, A.E.

    1988-02-01

    Salt structures, which develop due to sediment loading, gravity creep, and/or buoyancy, include boundary-fault grabens and half grabens, rollers, anticlines, domes and walls, diapirs, sills, massifs, and compressional toe structures. Associated features include fault systems and turtle structures. Of these, six directly relate to basin fill and all directly influence the distribution of reservoir facies. Salt structuring is initiated by sedimentation, which in turn is localized by salt withdrawal. Withdrawal produces individual salt structures, migrating sills, dissected massifs, and regional depocenters bordered by salt walls. Composite withdrawals dictate the patterns of basin fill. Relative rates of structural growth and sedimentation control the distribution of reservoir facies. When growth dominates, sands are channeled into lows. When sedimentation dominates and maintains flat surfaces, facies distribution is not impacted except where faulting develops. Turtle structures, developed by the inversion of peripheral synclines, can move sands into favorable structural position and/or serve as platforms for carbonate reservoir development. Salt growth varies with type structure, stage of development, and rate of sedimentation. Sedimentation at a specific location depends on basin position, sediment transport system, sea level stand, and rate of salt withdrawal. This paper presents techniques for using seismic data to determine the controls on salt structural growth and sedimentation and the patterns of basin fill and reservoir distribution.

  6. Tracking simulations for the HLS- II with a passive harmonic cavity in the symmetric and asymmetric fill patterns

    NASA Astrophysics Data System (ADS)

    Fan, Hao; Wu, Cong-Feng; Wang, Lin

    2012-11-01

    A simulation code that executes the tracking of longitudinal oscillations of the bunches for the double rf system of the Hefei Light Source II Project (HLS- II) is presented to estimate the mean beam lifetime and the Robinson instabilities. The tracking results show that the mean beam lifetime is in agreement with the analytical results and the system is stable when we tune the harmonic cavity in the optimum lengthening conditions. Moreover, the simulated results of the asymmetric fill pattern show that some bunches are compressed only with a 7% gap (3 gaps), which will lead to the reduction in the mean bunch lengthening and potential beam lifetime. It is demonstrated that HLS- II with a passive higher harmonic cavity is not suitable for operating in an asymmetric fill pattern.

  7. A model for the beam-filling effect associated with the microwave retrieval of rain

    NASA Technical Reports Server (NTRS)

    Graves, Charles E.

    1993-01-01

    Estimating rain rate from environmental microwave emissions is hampered by several difficulties. One of these difficulties is known as the beam-filling effect. Beam filling is the systematic error introduced when the microwave radiometer's field of view is not filled with uniform rain. Beam filling can have dramatic effects on rain-rate estimation, causing rain rates to be underestimated by as much as a factor of 2. The present study derives an approximate expression for beam filling that provides, in principle, a way to estimate this effect. In addition, this study deals only with single-channel microwave rain estimation over the ocean. The final results reveal that beam filling is essentially determined by the freezing level, the mean fraction of the footprint raining, and the footprint-averaged rain rate. Also, the numerical results appear to agree with other empirical studies. Furthermore, the analysis brings to light an interesting connection with rain threshold techniques for estimating area-averaged rain rates.

  8. Hydrogen-filled RF Cavities for Muon Beam Cooling

    SciTech Connect

    CHARLES, Ankenbrandt

    2009-04-17

    Ionization cooling requires low-Z energy absorbers immersed in a strong magnetic field and high-gradient, large-aperture RF cavities to be able to cool a muon beam as quickly as the short muon lifetime requires. RF cavities that operate in vacuum are vulnerable to dark-current- generated breakdown, which is exacerbated by strong magnetic fields, and they require extra safety windows that degrade cooling, to separate RF regions from hydrogen energy absorbers. RF cavities pressurized with dense hydrogen gas will be developed that use the same gas volume to provide the energy absorber and the RF acceleration needed for ionization cooling. The breakdown suppression by the dense gas will allow the cavities to operate in strong magnetic fields. Measurements of the operation of such a cavity will be made as functions of external magnetic field and charged particle beam intensity and compared with models to understand the characteristics of this technology and to develop mitigating strategies if necessary.

  9. Dynamic two-dimensional beam-pattern steering technique

    NASA Astrophysics Data System (ADS)

    Zhou, Shaomin; Yeh, Pochi; Liu, Hua-Kuang

    1993-06-01

    A dynamic two-dimensional laser-beam-pattern steering technique using photorefractive holograms in conjunction with electrically addressed spatial light modulators is proposed and investigated. The experimental results demonstrate the dynamic steering of random combinations of basis beam patterns. The proposed method has the advantages of random beam-pattern combination, good beam intensity uniformity, and higher diffraction efficiency compared with conventional methods.

  10. Modeling and experimental study of a honeycomb beam filled with damping particles

    NASA Astrophysics Data System (ADS)

    Ahmad, Nazeer; Ranganath, R.; Ghosal, Ashitava

    2017-03-01

    Honeycomb sandwich laminates which are the basic structural element of spacecraft have inherently low damping. In this paper, we propose to improve the damping characteristics of such structures by adding damping particles in the cells of the honeycomb. This paper presents modeling of a cantilever beam constructed with honeycomb structure with the hexagonal honeycomb cells, filled with particles. The beam is subjected to external dynamic loads and the interactions of damping particles with the walls of the cells and its overall effect on the frequency response function (FRF) and the damping of the beam are obtained. The discrete-element-method (DEM) is used to model the dynamics of the particles in conjunction with the governing equations of motion of the beam and the cell-walls. The particle-particle and particle-wall impact is modeled using Hertz's non-linear dissipative contact model for normal component and Coulomb's laws of friction for tangential component. Contiguous block of cells near the tip of the cantilever beam were filled with the damping particles and the beam was excited with a random signal near the fixed end. The damping and transfer functions obtained experimentally are compared to those obtained from the mathematical model and they are found to match very well. Further the model was used to study the effect of fill fraction, mass ratio, and the level of excitation signal on transfer function. Depending on the mass ratio and fill fraction, significant reductions in vibration levels are observed.

  11. Characterisation of Plasma Filled Rod Pinch electron beam diode operation

    NASA Astrophysics Data System (ADS)

    MacDonald, James; Bland, Simon; Chittenden, Jeremy

    2016-10-01

    The plasma filled rod pinch diode (aka PFRP) offers a small radiographic spot size and a high brightness source. It operates in a very similar to plasma opening switches and dense plasma focus devices - with a plasma prefill, supplied via a number of simple coaxial plasma guns, being snowploughed along a thin rod cathode, before detaching at the end. The aim of this study is to model the PFRP and understand the factors that affect its performance, potentially improving future output. Given the dependence on the PFRP on the prefill, we are making detailed measurements of the density (1015-1018 cm-3), velocity, ionisation and temperature of the plasma emitted from a plasma gun/set of plasma guns. This will then be used to provide initial conditions to the Gorgon 3D MHD code, and the dynamics of the entire rod pinch process studied.

  12. Numerical analysis on seismic behavior of reinforced concrete beam to concrete filled steel tubular column connections with ring-beam

    NASA Astrophysics Data System (ADS)

    Zhao, Yi.; Xu, Li. Hua.

    2016-06-01

    This paper presents numerical study of the seismic behavior of reinforced concrete beam to concrete filled steel tube column connections with ring-beam. The material stress-strain relations, element type and boundary condition are selected, which are consistent with actual situation. Then the seismic behavior of this type of joint are researched by ABAQUS, and finite element analyses are conducted under cyclic loading. Its parameters are discussed including thickness of steel tubular column wall, sectional dimension of the ring-beam and strength of the core concrete. The results show that the ultimate capacity of the connections is improved with sectional dimension of the ring-beam increased. In the meanwhile, the influence on skeleton curve of the joints is slight of which included thickness of steel tubular column wall and strength of the core concrete.

  13. Studies of a gas-filled helical muon beam cooling channel

    SciTech Connect

    Yonehara, K.; Derbenev, Y.; Johnson, R.P.; Roberts, T.J.; /MUONS Inc., Batavia

    2006-06-01

    A helical cooling channel (HCC) can quickly reduce the six dimensional phase space of muon beams for muon colliders, neutrino factories, and intense muon sources. The HCC is composed of solenoidal, helical dipole, and helical quadrupole magnetic fields to provide the focusing and dispersion needed for emittance exchange as the beam follows an equilibrium helical orbit through a continuous homogeneous absorber. The beam dynamics of a gas-filled helical muon beam cooling channel is studied by using Monte Carlo simulations. The results verify the cooling theory [1] of the helical magnet. The cooling performance has been improved by correcting chromatic aberration and the non-linear effects caused by the ionization energy loss process. With these improvements, a simulated cooling channel of 160 meters length has achieved a reduction of 6-dimensional (6D) phase space by a factor of 50,000.

  14. Understanding the Relationship Between Filling Pattern and Part Quality in Die Casting

    SciTech Connect

    Jerald Brevick; R. Allen Miller

    2004-03-15

    The overall objective of this research project was to investigate phenomena involved in the filling of die cavities with molten alloy in the cold chamber die-casting process. It has long been recognized that the filling pattern of molten metal entering a die cavity influences the quality of die-cast parts. Filling pattern may be described as the progression of molten metal filling the die cavity geometry as a function of time. The location, size and geometric configuration of points of metal entry (gates), as well as the geometry of the casting cavity itself, have great influence on filling patterns. Knowledge of the anticipated filling patterns in die-castings is important for designers. Locating gates to avoid undesirable flow patterns that may entrap air in the casting is critical to casting quality - as locating vents to allow air to escape from the cavity (last places to fill). Casting quality attributes that are commonly flow related are non-fills, poor surface finish, internal porosity due to trapped air, cold shuts, cold laps, flow lines, casting skin delamination (flaking), and blistering during thermal treatment.

  15. Current neutralization and focusing of intense ion beams with a plasma-filled solenoidal lens. I

    SciTech Connect

    Oliver, B.V.; Sudan, R.N.

    1996-12-01

    The response of the magnetized plasma in an axisymmetric, plasma-filled, solenoidal magnetic lens, to intense light ion beam injection is studied. The lens plasma fill is modeled as an inertialess, resistive, electron magnetohydrodynamic (EMHD) fluid since characteristic beam times {tau} satisfy 2{pi}/{omega}{sub {ital pe}},2{pi}/{Omega}{sub {ital e}}{lt}{tau}{le}2{pi}/{Omega}{sub {ital i}} ({omega}{sub {ital pe}} is the electron plasma frequency and {Omega}{sub {ital e},{ital i}} are the electron, ion gyrofrequencies). When the electron collisionality satisfies {nu}{sub {ital e}}{lt}{Omega}{sub {ital e}}, the linear plasma response is determined by whistler wave dynamics. In this case, current neutralization of the beam is reduced on the time scale for whistler wave transit across the beam. The transit time is inversely proportional to the electron density and proportional to the angle of incidence of the beam with respect to the applied solenoidal field. In the collisional regime ({nu}{sub {ital e}}{gt}{Omega}{sub {ital e}}) the plasma return currents decay on the normal diffusive time scale determined by the conductivity. The analysis is supported by two-and-one-half dimensional hybrid particle-in-cell simulations. {copyright} {ital 1996 American Institute of Physics.}

  16. Reduction of Non-uniform Beam Filling Effects by Vertical Decorrelation: Theory and Simulations

    NASA Technical Reports Server (NTRS)

    Short, David; Nakagawa, Katsuhiro; Iguchi, Toshio

    2013-01-01

    Algorithms for estimating precipitation rates from spaceborne radar observations of apparent radar reflectivity depend on attenuation correction procedures. The algorithm suite for the Ku-band precipitation radar aboard the Tropical Rainfall Measuring Mission satellite is one such example. The well-known problem of nonuniform beam filling is a source of error in the estimates, especially in regions where intense deep convection occurs. The error is caused by unresolved horizontal variability in precipitation characteristics such as specific attenuation, rain rate, and effective reflectivity factor. This paper proposes the use of vertical decorrelation for correcting the nonuniform beam filling error developed under the assumption of a perfect vertical correlation. Empirical tests conducted using ground-based radar observations in the current simulation study show that decorrelation effects are evident in tilted convective cells. However, the problem of obtaining reasonable estimates of a governing parameter from the satellite data remains unresolved.

  17. Determinants of filled/empty optical illusion: differential effects of patterning.

    PubMed

    Wackermann, Jiri

    2012-01-01

    A subdivided path in the visual field appears longer than an empty path of the same length. This effect may be attributed to the division of the path into multiple segments, or to an influence of the visual elements used to mark the subdivision, and thus filling-up the estimated space. To address this question, we used two series of stimuli, in which the spatial distribution of the filling optical mater, or the form of the dividers, was varied while the relative coverage of the filled space was kept constant. We found significant dependence of the effect magnitude on a number of filling elements as well as on their form. These results indicate that the illusory space expansion is not merely an effect of 'filling-up' the space, but it also depends on the filling pattern. Consequences of these findings for the theory of the Oppel-Kundt phenomenon are briefly discussed.

  18. Artefacts in Cone Beam CT Mimicking an Extrapalatal Canal of Root-Filled Maxillary Molar.

    PubMed

    Camilo, Carla Cristina; Brito-Júnior, Manoel; Faria-E-Silva, André Luis; Quintino, Alex Carvalho; de Paula, Adrianne Freire; Cruz-Filho, Antônio Miranda; Sousa-Neto, Manoel Damião

    2013-01-01

    Despite the advantages of cone-beam computed tomography (CBCT), the images provided by this diagnostic tool can produce artifacts and compromise accurate diagnostic assessment. This paper describes an endodontic treatment of a maxillary molar where CBCT images suggested the presence of a nonexistent third root canal in the palatal root. An endodontic treatment was performed in a first maxillary molar with palatal canals, and the tooth was restored with a cast metal crown. The patient returned four years later presenting with a discomfort in chewing, which was reduced after occlusal adjustment. CBCT was prescribed to verify additional diagnostic information. Axial scans on coronal, middle, and apical palatal root sections showed images similar to a third root canal. However, sagittal scans demonstrated that these images were artifacts caused by root canal fillings. A careful interpretation of CBCT images in root-filled teeth must be done to avoid mistakes in treatment.

  19. Artefacts in Cone Beam CT Mimicking an Extrapalatal Canal of Root-Filled Maxillary Molar

    PubMed Central

    Camilo, Carla Cristina; Brito-Júnior, Manoel; Faria-e-Silva, André Luis; Quintino, Alex Carvalho; de Paula, Adrianne Freire; Cruz-Filho, Antônio Miranda; Sousa-Neto, Manoel Damião

    2013-01-01

    Despite the advantages of cone-beam computed tomography (CBCT), the images provided by this diagnostic tool can produce artifacts and compromise accurate diagnostic assessment. This paper describes an endodontic treatment of a maxillary molar where CBCT images suggested the presence of a nonexistent third root canal in the palatal root. An endodontic treatment was performed in a first maxillary molar with palatal canals, and the tooth was restored with a cast metal crown. The patient returned four years later presenting with a discomfort in chewing, which was reduced after occlusal adjustment. CBCT was prescribed to verify additional diagnostic information. Axial scans on coronal, middle, and apical palatal root sections showed images similar to a third root canal. However, sagittal scans demonstrated that these images were artifacts caused by root canal fillings. A careful interpretation of CBCT images in root-filled teeth must be done to avoid mistakes in treatment. PMID:23606995

  20. Integrated routing and fill for self-aligned double patterning (SADP) using grid-based design

    NASA Astrophysics Data System (ADS)

    Song, Youngsoo; Lee, Jeemyung; Lee, Seongmin; Shin, Youngsoo

    2016-03-01

    Self-aligned double patterning (SADP) has been proposed as an alternative patterning solution for sub-10nm technology because of delay of advanced lithography beyond 193nm ArF. In conventional SADP, line and space style of dummy metal fills are inserted once main design is complete. A large buffer distance is required around the main design because no further verification of main design (in presence of fills) is performed. This causes irregular pattern density, which becomes a source of process variations. We propose integrated-fill, in which main design and dummy fill insertion are performed together. This requires a change in overall design flow, which we discuss. Integrated-fill is demonstrated in M2 layer of SADP process; M2 density increases by 15.7% with 2.3% reduction in standard deviation of density distribution; metal thickness variation is also reduced by 24%. More dummy fills cause increased coupling capacitance, which however is shown to be insignificant.

  1. Simulation of beam-induced plasma in gas-filled rf cavities

    NASA Astrophysics Data System (ADS)

    Yu, Kwangmin; Samulyak, Roman; Yonehara, Katsuya; Freemire, Ben

    2017-03-01

    Processes occurring in a radio-frequency (rf) cavity, filled with high pressure gas and interacting with proton beams, have been studied via advanced numerical simulations. Simulations support the experimental program on the hydrogen gas-filled rf cavity in the Mucool Test Area (MTA) at Fermilab, and broader research on the design of muon cooling devices. space, a 3D electromagnetic particle-in-cell (EM-PIC) code with atomic physics support, was used in simulation studies. Plasma dynamics in the rf cavity, including the process of neutral gas ionization by proton beams, plasma loading of the rf cavity, and atomic processes in plasma such as electron-ion and ion-ion recombination and electron attachment to dopant molecules, have been studied. Through comparison with experiments in the MTA, simulations quantified several uncertain values of plasma properties such as effective recombination rates and the attachment time of electrons to dopant molecules. Simulations have achieved very good agreement with experiments on plasma loading and related processes. The experimentally validated code space is capable of predictive simulations of muon cooling devices.

  2. Semi-active control of a sandwich beam partially filled with magnetorheological elastomer

    NASA Astrophysics Data System (ADS)

    Dyniewicz, Bartłomiej; Bajkowski, Jacek M.; Bajer, Czesław I.

    2015-08-01

    The paper deals with the semi-active control of vibrations of structural elements. Elastomer composites with ferromagnetic particles that act as magnetorheological fluids are used. The damping coefficient and the shear modulus of the elastomer increases when it is exposed to an electro-magnetic field. The control of this process in time allows us to reduce vibrations more effectively than if the elastomer is permanently exposed to a magnetic field. First the analytical solution for the vibrations of a sandwich beam filled with an elastomer is given. Then the control problem is defined and applied to the analytical formula. The numerical solution of the minimization problem results in a periodic, perfectly rectangular control function if free vibrations are considered. Such a temporarily acting magnetic field is more efficient than a constantly acting one. The surplus reaches 20-50% or more, depending on the filling ratio of the elastomer. The resulting control was verified experimentally in the vibrations of a cantilever sandwich beam. The proposed semi-active control can be directly applied to engineering vibrating structural elements, for example helicopter rotors, aircraft wings, pads under machines, and vehicles.

  3. Heavy ion beam propagation through a gas-filled chamber for inertial confinement fusion

    SciTech Connect

    Barboza, Nigel Oswald

    1996-10-01

    The work presented here evaluates the dynamics of a beam of heavy ions propagating through a chamber filled with gas. The motivation for this research stems from the possibility of using heavy ion beams as a driver in inertial confinement fusion reactors for the purpose of generating electricity. Such a study is important in determining the constraints on the beam which limit its focus to the small radius necessary for the ignition of thermonuclear microexplosions which are the source of fusion energy. Nuclear fusion is the process of combining light nuclei to form heavier ones. One possible fusion reaction combines two isotopes of hydrogen, deuterium and tritium, to form an alpha particle and a neutron, with an accompanying release of ~17.6 MeV of energy. Generating electricity from fusion requires that we create such reactions in an efficient and controlled fashion, and harness the resulting energy. In the inertial confinement fusion (ICF) approach to energy production, a small spherical target, a few millimeters in radius, of deuterium and tritium fuel is compressed so that the density and temperature of the fuel are high enough, ~200 g/cm3 and ~20 keV, that a substantial number of fusion reactions occur; the pellet microexplosion typically releases ~350 MJ of energy in optimized power plant scenarios.

  4. Influence of Intense Beam in High Pressure Hydrogen Gas Filled RF Cavities

    SciTech Connect

    Yonehara, K.; Chung, M.; Collura, M.G.; Jana, M.R.; Leonova, M.; Moretti, A.; Popovic, M.; Schwarz, T.; Tollestrup, A.; Johnson, R.P.; Franagan, G.; /Muons, Inc. /IIT

    2012-05-01

    The influence of an intense beam in a high-pressure gas filled RF cavity has been measured by using a 400 MeV proton beam in the Mucool Test Area at Fermilab. The ionization process generates dense plasma in the cavity and the resultant power loss to the plasma is determined by measuring the cavity voltage on a sampling oscilloscope. The energy loss has been observed with various peak RF field gradients (E), gas pressures (p), and beam intensities in nitrogen and hydrogen gases. Observed RF energy dissipation in single electron (dw) in N{sub 2} and H{sub 2} gases was 2 10{sup -17} and 3 10{sup -17} Joules/RF cycle at E/p = 8 V/cm/Torr, respectively. More detailed dw measurement have been done in H{sub 2} gas at three different gas pressures. There is a clear discrepancy between the observed dw and analytical one. The discrepancy may be due to the gas density effect that has already been observed in various experiments.

  5. Theory of beam-plasma instability in a periodic plasma-filled waveguide.

    PubMed

    Zaginaylov, G I; Rozhkov, A A; Raguin, J Y

    1999-12-01

    The beam-plasma wave interaction in a periodic plasma-filled waveguide is treated in a mathematically correct manner on the basis of the integral equation (IE) method. It has been shown that the relevant boundary-value problem could be reduced to an IE with a singular kernel for the longitudinal component of the electric field on the waveguide axis. The regularization of the IE was performed by extracting the static part of the kernel. The resulting IE of the second kind with a regular kernel, being rather convenient for a numerical analysis, is treated in a quasistatic approximation as a spectral problem. First-order expressions for eigenfunctions, and an infinite set of dispersion relations linking a wave number and frequency of plasma oscillations which separate radial branches of plasma oscillations from axial ones, have been obtained in the closed analytical form, thus enabling us to avoid the problem with the so-called "dense" spectrum. The solutions of the relevant "cold" dispersion relations establish a periodical dependence of the frequency on the wave number over several periods within the accuracy of order of the neglected terms. In the presence of an electron beam they turn out to be unstable near frequencies providing the resonances of the beam with spatial plasma harmonics. Evaluations of the instability saturation level predict a more efficient beam-plasma wave energy transfer compared with those following from a conventional theoretical analysis based on the formulation of a dispersion relation in terms of an infinite determinant, with following truncation of the latter to the finite sized relation.

  6. Patterned electrochemical deposition of copper using an electron beam

    SciTech Connect

    Heijer, Mark den; Shao, Ingrid; Reuter, Mark C.; Ross, Frances M.; Radisic, Alex

    2014-02-01

    We describe a technique for patterning clusters of metal using electrochemical deposition. By operating an electrochemical cell in the transmission electron microscope, we deposit Cu on Au under potentiostatic conditions. For acidified copper sulphate electrolytes, nucleation occurs uniformly over the electrode. However, when chloride ions are added there is a range of applied potentials over which nucleation occurs only in areas irradiated by the electron beam. By scanning the beam we control nucleation to form patterns of deposited copper. We discuss the mechanism for this effect in terms of electron beam-induced reactions with copper chloride, and consider possible applications.

  7. Focused ion beam lithography and anodization combined nanopore patterning.

    PubMed

    Lu, Kathy; Zhao, Jingzhong

    2010-10-01

    In this study, focused ion beam lithography and anodization are combined to create different nanopore patterns. Uniform-, alternating-, and gradient-sized shallow nanopore arrays are first made on high purity aluminum by focused ion beam lithography. These shallow pore arrays are then used as pore initiation sites during anodization by different electrolytes. Depending on the nature of the anodization electrolyte, the nanopore patterns by focused ion beam lithography play different roles in further pore development during anodization. The pore-to-pore distance by focused ion beam lithography should match with that by anodization for guided pore development to be effective. Ordered and heterogeneous nanopore arrays are obtained by the focused ion beam lithography and anodization combined approach.

  8. High pressure gas filled RF cavity beam test at the Fermilab Mucool test area

    NASA Astrophysics Data System (ADS)

    Freemire, Ben

    With a new generation of lepton colliders being conceived, muons have been proposed as an alternative particle to electrons. Muons lose less energy to synchrotron radiation and a Muon Collider can provide luminosity within a smaller energy range than a comparable electron collider. This allows a circular collider to be built. As part of the accelerator, it would also be possible to allow the muons to decay to study neutrinos. Because the muon is an unstable particle, a muon beam must be cooled and accelerated within a short amount of time. Muons are generated with a huge phase space, so radio frequency cavities placed in strong magnetic fields are required to bunch, focus, and accelerate the muons. Unfortunately, traditional vacuum RF cavities have been shown to break down in the magnetic fields necessary. To successfully operate RF cavities in strong magnetic fields, the cavity can be filled with a high pressure gas in order to mitigate breakdown. The gas has the added benefit of providing cooling for the beam. The electron-ion plasma created in the cavity by the beam absorbs energy and degrades the accelerating electric field of the cavity. As electrons account for the majority of the energy loss in the cavity, their removal in a short time is highly desirable. The addition of an electronegative dopant gas can greatly decrease the lifetime of an electron in the cavity. Measurements in pure hydrogen of the energy consumption of electrons in the cavity range in 10-18 and 10-16 joules per RF cycle per electron. When hydrogen doped with dry air is used, measurements of the power consumption indicate an energy loss range of 10-20 to 10-18 joules per RF cycle per ion, two orders of magnitude improvement over non-doped measurements. The lifetime of electrons in a mixture of hydrogen gas and dry air has been measured from < 1 ns, up to 200 ns. The results extrapolated to the parameters of a Neutrino Factory and Muon Collider indicate that a high pressure gas filled RF

  9. Pattern formation in the flow between two horizontal coaxial cylinders with a partially filled gap

    NASA Astrophysics Data System (ADS)

    Mutabazi, Innocent; Hegseth, John J.; Andereck, C. David; Wesfreid, Jose E.

    1988-11-01

    Flow between two horizontal coaxial cylinders with a partially filled gap is subject to several types of centrifugal instabilities which lead to the formation of a variety of spatial patterns. An experimental investigation has shown that there are five distinct branches of primary instabilities occurring in the system and that four codimension-2 points are easily reached. Theoretical predictions are in qualitative agreement with the observations.

  10. Beaming and filtering at terahertz frequencies in liquid crystal filled metallic grating

    NASA Astrophysics Data System (ADS)

    Lo Forti, Daniele; de Ceglia, Domenico; Vincenti, Maria A.; Scalora, Michael; Lindquist, Robert G.

    2013-09-01

    The increasing interest in the terahertz frequency range is motivated by the unique property of sub-millimeter waves to penetrate any nonmetallic materials such as fabric and plastic, and sense objects distinctive signatures. Furthermore, because of its low photon energy, terahertz radiation can be used in medical applications for accurate imaging without damaging tissues. For these reasons there is a growing need of devices dedicated to control the radiation in this frequency range. Current established technology uses non-tunable, mesh-like filters and mechanical mirrors to filter and manipulate THz radiation. We study electrically-controlled beaming and filtering abilities of sub-wavelength metallic gratings. The geometry consists of a finite array of slits in a metallic film separated by spacers and filled with liquid crystal (LC). We exploit the Fabry-Perot (FP) like resonances of the slits to filter THz radiation. We then simulate the application of an external voltage across the metallic grating in order to generate an electro-optic torque force on the LC molecules and change the dielectric constant inside the slits. This results in a large tuning effect on the FP resonances. We also predict that a linear voltage distribution across the grating induces a linear phase delay resulting in a beamsteering action for radiation incoming at grazing incidence.

  11. Exercise Tolerance and the Post Exercise Diastolic Filling Pattern in Patients With the Resting Impaired Relaxation

    PubMed Central

    Lavine, Steven J.; Walsh, Thomas

    2011-01-01

    Background In patients with normal LV systolic function, cardiac output increases with exercise mediated by increased stroke volume early in exercise and an increase in heart rate later in exercise. Despite normal LV systolic function, patients who display an impaired relaxation pattern may have a reduced exercise tolerance. We hypothesized that the resting impaired relaxation pattern that persists during exercise results in reduced LV filling volume and reduced exercise tolerance. Methods We evaluated consecutive exercise echocardiograms performed at Harper Hospital from 1998-2000 for patients with sinus rhythm, normal resting wall motion and ejection fraction (> 55%), evidence of resting impaired relaxation, and a negative exercise echocardiogram. There were 49 patients fitting the above criteria who were compared with a group of age and sex matched patients (43 patients) with a normal rest and exercise echocardiogram with normal resting transmitral Doppler. Rest and post exercise echocardiography and Doppler parameters were obtained. Results Patients in the impaired relaxation group demonstrated shorter exercise times as compared to the normal control group (8.8 ± 1.6 versus 9.7 ± 2.0 minutes, P < 0.001). In patients with normal resting transmitral diastolic filling, there was an increased the extent of atrial contribution to LV filling volume post exercise associated with shortening of isovolumic relaxation. Two patterns were seen in the impaired relaxation group post exercise. In 1 subgroup in which E/A ratio decreased post exercise, exercise duration was reduced (7.4 ± 1.3 minutes, P < 0.001) as compared to the subgroup with E/A increase (9.6 ± 1.2 minutes) post exercise which was similar to normal controls. Forward stepwise regression indicated that exercise time was primarily related to E/A change post exercise for all patient groups (r = 0.625, P = 0.0008). Specifically, this was true for patients with E/A reversal at rest (r = 0.584, P = 0

  12. NANOSTRUCTURE PATTERNING UNDER ENERGETIC PARTICLE BEAM IRRADIATION

    SciTech Connect

    Wang, Lumin; Lu, Wei

    2013-01-31

    Energetic ion bombardment can lead to the development of complex and diverse nanostructures on or beneath the material surface through induced self-organization processes. These self-organized structures have received particular interest recently as promising candidates as simple, inexpensive, and large area patterns, whose optical, electronic and magnetic properties are different from those in the bulk materials [1-5]. Compared to the low mass efficiency production rate of lithographic methods, these self-organized approaches display new routes for the fabrication of nanostructures over large areas in a short processing time at the nanoscale, beyond the limits of lithography [1,4]. Although it is believed that surface nanostructure formation is based on the morphological instability of the sputtered surface, driven by a kinetic balance between roughening and smoothing actions [6,7], the fundamental mechanisms and experimental conditions for the formation of these nanostructures has still not been well established, the formation of the 3-D naopatterns beneath the irradiated surface especially needs more exploration. During the last funding period, we have focused our efforts on irradiation-induced nanostructures in a broad range of materials. These structures have been studied primarily through in situ electron microscopy during electron or ion irradiation. In particular, we have performed studies on 3-D void/bubble lattices (in metals and CaF2), embedded sponge-like porous structure with uniform nanofibers in irradiated semiconductors (Ge, GaSb, and InSb), 2-D highly ordered pattern of nanodroplets (on the surface of GaAs), hexagonally ordered nanoholes (on the surface of Ge), and 1-D highly ordered ripple and periodic arrays (of Cu nanoparticles) [3,8-11]. The amazing common feature in those nanopatterns is the uniformity of the size of nanoelements (nanoripples, nanodots, nanovoids or nanofibers) and the distance separating them. Our research focuses on the

  13. Design flow automation for variable-shaped beam pattern generators

    NASA Astrophysics Data System (ADS)

    Bloecker, Martin; Ballhorn, Gerd

    2002-07-01

    Raster scan pattern generators have been used in the photomask industry for many years. Methods and software tools for data preparation for these pattern generators are well established and have been integrated into design flows with a high degree of automation. But the growing requirements for pattern fidelity have lead to the introduction of 50 kV variable shaped beam pattern generators. Due to their different writing strategy these tools use proprietary data formats and in turn require an optimized data preparation. As a result the existing design flow has to be adopted to account for these requirements. Due to the fact that cycle times have grown severely over the last years the automation of this adopted design flow will not only enhance the design flow quality by avoiding errors during manual operations but will also help to reduce turn-around times. We developed and implemented an automated design flow for a variable shaped beam pattern generator which had to fulfill two conflicting requirements: Well established automated tools originally developed for raster scan pattern generators had to be retained with only slight modifications to avoid the (re)implementation and the concurrent usage of two systems while on the other hand data generation especially during fracturing had to be optimized for a variable shaped beam pattern generator.

  14. Cavity shape transformation during peeling on elastic microchannel-patterned substrates filled with a viscous liquid.

    PubMed

    Chaudhari, Nayantika; Deshpande, Tushar; Singh, Yogesh R G; Patil, Sandip; Kulkarni, Manish; Raut, Janhavi; Sharma, Ashutosh

    2017-03-10

    Inspired by the detachment mechanics of natural adhesive pads, we studied the change in cavity shape during peel tests on a 10% cross-linked polydimethylsiloxane (PDMS) elastic microchannel filled with 1% cross-linked viscous PDMS liquid (patterned bilayer). During peeling, we explored cavity shape as a function of microchannel dimensions and correlated the dimensionless cavity shape factor (CSF) and characteristic stress decay length, K(-1). The peel test on the liquid-filled elastic microchannel shows three distinct cavity-shape regimes, elliptical, circular, and binary, based on the values of CSF and K(-1). Such cavity formation and shape regimes could be important for improving the design of pressure-sensitive adhesives.

  15. Patterning of membrane masks for projection e-beam lithography

    NASA Astrophysics Data System (ADS)

    Fetter, Linus A.; Biddick, Christopher J.; Blakey, Myrtle I.; Liddle, James A.; Peabody, Milton L., Jr.; Novembre, Anthony E.; Tennant, Donald M.

    1996-12-01

    A process for high-resolution patterning of the membrane- type masks used in the SCALPEL (SCattering with Angular Limitation in Projection Electron-beam Lithography) lithography system is described. SCALPEL is a 4X projection electron beam lithography tool with the potential to extend commercial lithographic capability well into the deep sub-micron range: the recently-completed SCALPEL proof- of-concept (SPOC) system has printed 0.08 micrometers lines in thick resist on Si. The details of the patterning process we currently employ and metrology results from the first series of masks are presented here. The SPOC mask blank consists of a segmented W-coated SiN (Si-rich) membrane, fabricated on a 4' Si wafer. The blank is patterned with 45 different test chips using a vector-scanned e-beam lithography tool. Metrology is performed on completed masks, and results from measurements of line-edge roughness, CD linearity, and pattern uniformity are presented. We examine the need for proximity effect correction of the pattern data, and compare the effect of correction on pattern data file size for a variety of mask technologies.

  16. Optimal beam pattern to maximize inclusion residence time in an electron beam melting hearth

    SciTech Connect

    Powell, A.; Pal, U.; Avyle, J. van den

    1997-02-01

    Approximate probabilities of inclusion survival through an electron beam melting hearth are computed from nitride dissolution rates, flotation velocities, and residence times. Dissolution rates were determined by measuring shrinkage rates of pure TiN and nitrided sponge in small pools of molten titanium in an electron beam melting hearth. Flotation velocities were calculated using correlations for fluid flow around spheres, and show that particles sink or float unless their densities are extremely close to that of molten titanium. Flow field characteristics which lead to effective inclusion removal are discussed in terms of heat flux pattern required to produce them, based on the electron beam`s unique ability to impart a nearly arbitrary heat flux pattern to the melt surface.

  17. Effect of a transverse magnetic field on the generation of electron beams in the gas-filled diode

    NASA Astrophysics Data System (ADS)

    Baksht, E. H.; Burachenko, A. G.; Erofeev, M. V.; Kostyrya, I. D.; Lomaev, M. I.; Rybka, D. V.; Tarasenko, V. F.

    2008-06-01

    The effect of a transverse magnetic field (0.080 and 0.016 T) on generation of an electron beam in the gas-filled diode is experimentally investigated. It is shown that, at voltage U = 25 kV across the diode and a low helium pressure (45 Torr), the transverse magnetic field influences the beam current amplitude behind a foil and its distribution over the foil cross section. At elevated pressures and under the conditions of ultrashort avalanche electron beam formation in helium, nitrogen, and air, the transverse magnetic field (0.080 and 0.016 T) has a minor effect on the amplitude and duration of the beam behind the foil. It is established that, when the voltage of the pulse generator reaches several hundreds of kilovolts, some runaway electrons (including the electrons from the discharge plasma near the cathode) are incident on the side walls of the diode.

  18. Patterning and imaging with electrons: assessing multi-beam SEM for e-beam structured CMOS samples

    NASA Astrophysics Data System (ADS)

    Garbowski, Tomasz; Panteleit, Friedhelm; Dellemann, Gregor; Gutsch, Manuela; Hohle, Christoph; Reich, Elke; Rudolph, Matthias; Steidel, Katja; Thrun, Xaver; Zeidler, Dirk

    2016-03-01

    Electron optics can assist in the fabrication of semiconductor devices in many challenges that arise from the ongoing decrease of structure size. Examples are augmenting optical lithography by electron beam direct write strategies and high-throughput imaging of patterned structures with multiple beam electron microscopes. We use multiple beam electron microscopy to image semiconductor wafers processed by electron beam lithography.

  19. Flow patterns of natural convection in an air-filled vertical cavity

    NASA Astrophysics Data System (ADS)

    Wakitani, Shunichi

    1998-08-01

    Flow patterns of two-dimensional natural convection in a vertical air-filled tall cavity with differentially heated sidewalls are investigated. Numerical simulations based on a finite difference method are carried out for a wide range of Rayleigh numbers and aspect ratios from the onset of the steady multicellular flow, through the reverse transition to the unicellular pattern, to the unsteady multicellular flow. For aspect ratios (height/width) from 10 to 24, the various cellular structures characterized by the number of secondary cells are clarified from the simulations by means of gradually increasing Rayleigh number to 106. Unsteady multicellular solutions are found in some region of Rayleigh numbers less than those at which the reverse transition has occurred.

  20. The beam filling error in the Nimbus 5 electronically scanning microwave radiometer observations of Global Atlantic Tropical Experiment rainfall

    NASA Technical Reports Server (NTRS)

    Short, David A.; North, Gerald R.

    1990-01-01

    A comparison of rain rates retrieved from the Nimbus 5 electronically scanning microwave radiometer brightness temperatures and observed from shipboard radars during the Global Atlantic Tropical Experiment (GATE) phase I shows that the beam filling error is the major source of discrepancy between the two. When averaged over a large scene (the GATE radar array, 400 km in diameter), the beam filling error is quite stable, being 50 percent of the observed rain rate. This suggests the simple procedure of multiplying retrieved rain rates by 2 (correction factor). A statistical model of the beam filling error is developed by envisioning an idealized instrument field-of-view that encompasses an entire gamma distribution of rain rates. A modeled correction factor near 2 is found for rain rate and temperature characteristics consistent with GATE conditions. The statistical model also suggests that the correction factor varies from 1.5 to 2.5 for suppressed to enhanced tropical convective regimes, and decreases to 1.5 as the freezing level and average depth of the rain column decreases to 2.5 km.

  1. Bond patterns and charge-order amplitude in quarter-filled charge-transfer solids

    NASA Astrophysics Data System (ADS)

    Clay, R. T.; Ward, A. B.; Gomes, N.; Mazumdar, S.

    2017-03-01

    Most quasi-one-dimensional (quasi-1D) quarter-filled organic charge-transfer solids (CTS) with insulating ground states have two thermodynamic transitions: a high-temperature metal-insulator transition followed by a low-temperature magnetic transition. This sequence of transitions can be understood within the 1D Peierls-extended Hubbard (PEH) model. However, in some quasi-1D CTS both transitions occur simultaneously in a direct metal to spin-gapped insulator transition. In this second class of materials the organic stack bond distortion pattern does not follow the pattern of a second dimerization of a dimer lattice. These materials also display charge ordering of a large amplitude below the transition. Using quantum Monte Carlo methods we show that the same PEH model can be used to understand both classes of materials, however, within different parameter regions. We discuss the relevance of our work to experiments on several quarter-filled conductors, focusing in particular on the materials (EDO-TTF)2X and (DMEDO-TTF)2X .

  2. Nanostructure patterning on flexible substrates using electron beam lithography

    NASA Astrophysics Data System (ADS)

    Nagaraj, K. S.; Sangeeth, K.; Hegde, G. M.

    2014-06-01

    Patterning nanostructures on flexible substrates plays a key role in the emerging flexible electronics technology. The flexible electronic devices are inexpensive and can be conformed to any shape. The potential applications for such devices are sensors, displays, solar cells, RFID, high-density biochips, optoelectronics etc. E-beam lithography is established as a powerful tool for nanoscale fabrication, but its applicability on insulating flexible substrates is often limited because of surface charging effects. This paper presents the fabrication of nanostructures on insulating flexible substrates using low energy E-beam lithography along with metallic layers for charge dissipation. Nano Structures are patterned on different substrates of materials such as acetate and PET foils. The fabrication process parameters such as the proximity gap of exposure, the exposure dosage and developing conditions have been optimized for each substrate.

  3. Young's double-slit interference pattern from a twisted beam

    NASA Astrophysics Data System (ADS)

    Emile, Olivier; Emile, Janine

    2014-10-01

    A wide range of diffractive elements have been used to evaluate the topological charge of Laguerre-Gaussian beams. Here, we show theoretically and experimentally that this charge can be simply and readily measured from the interference pattern in Young's double-slit experiment. It can be evaluated from the twisting order of the interference. The results are confronted with previously published studies. The potentialities of the method are then compared with existing techniques.

  4. Pattern evolution during ion beam sputtering; reductionistic view

    NASA Astrophysics Data System (ADS)

    Kim, J.-H.; Kim, J.-S.

    2016-09-01

    The development of the ripple pattern during the ion beam sputtering (IBS) is expounded via the evolution of its constituent ripples. For that purpose, we perform numerical simulation of the ripple evolution that is based on Bradley-Harper model and its non-linear extension. The ripples are found to evolve via various well-defined processes such as ripening, averaging, bifurcation and their combinations, depending on their neighboring ripples. Those information on the growth kinetics of each ripple allow the detailed description of the pattern development in real space that the instability argument and the diffraction study both made in k-space cannot provide.

  5. Silicide induced ion beam patterning of Si(001).

    PubMed

    Engler, Martin; Frost, Frank; Müller, Sven; Macko, Sven; Will, Moritz; Feder, René; Spemann, Daniel; Hübner, René; Facsko, Stefan; Michely, Thomas

    2014-03-21

    Low energy ion beam pattern formation on Si with simultaneous co-deposition of Ag, Pd, Pb, Ir, Fe or C impurities was investigated by in situ scanning tunneling microscopy as well as ex situ atomic force microscopy, scanning electron microscopy, transmission electron microscopy and Rutherford backscattering spectrometry. The impurities were supplied by sputter deposition. Additional insight into the mechanism of pattern formation was obtained by more controlled supply through e-beam evaporation. For the situations investigated, the ability of the impurity to react with Si, i.e. to form a silicide, appears to be a necessary, but not a sufficient condition for pattern formation. Comparing the effects of impurities with similar mass and nuclear charge, the collision kinetics is shown to be not of primary importance for pattern formation. To understand the observed phenomena, it is necessary to assume a bi-directional coupling of composition and height fluctuations. This coupling gives rise to a sensitive dependence of the final morphology on the conditions of impurity supply. Because of this history dependence, the final morphology cannot be uniquely characterized by a steady state impurity concentration.

  6. Electron Beam Pattern Writer For X-Ray Masks

    NASA Astrophysics Data System (ADS)

    Viswanathan, R.; Wilson, A. D.; Lafuente, J.; Voelker, H.; Kern, A.

    1984-03-01

    This paper discusses the capabilities of a vector scan electron-beam system as an X-ray mask writer for pattern geometries at and below one-half micron. The noise level in the deflection system has been reduced to an RMS value of 150 A over a 0.5 mm deflection field, thus making our exposure system usable in the one-quarter micron regime. Pattern geometries below 2000 A have been fabricated on a thin membrane. Drift compensation techniques, implemented in software, have reduced placement errors over the entire mask to less than 700 A. Accomplishments in the areas of noise reduction, bandwidth error compensation, system resolution, and improvements in pattern placement accuracy are discussed.

  7. Evaluation of technical quality and periapical health of root-filled teeth by using cone-beam CT

    PubMed Central

    Bilge Gülsüm, NUR; Evren, OK; ALTUNSOY, Mustafa; AĞLARCI, Osman Sami; ÇOLAK, Mehmet; GÜNGÖR, Enes

    2014-01-01

    Objective This study aimed to assess the quality of root fillings, coronal restorations, complications of all root-filled teeth and their association with apical periodontitis (AP) detected by cone-beam computed tomography (CBCT) images from an adult Turkish subpopulation. Material and Methods The sample for this study consisted of 242 patients (aging from 15 to 72 years) with 522 endodontically treated teeth that were assessed for technical quality of the root canal filling and periapical status of the teeth. Additionally, the apical status of each root-filled tooth was assessed according to the gender, dental arch, tooth type and age classification, undetected canals, instrument fracture, root fracture, apical resorption, apical lesion, furcation lesion and type and quality of the coronal structure. Statistical analysis was performed using percentages and chi-square test. Results The success rate of the root canal treatment was of 54.4%. The success rates of adequate and inadequate root canal treatment were not significantly different (p>0.05). Apical periodontitis was found in 228 (45.6%) teeth treated for root canals. Higher prevalence of AP was found in patients aging from 20 to 29 years [64 (27%) teeth] and in anterior (canines and incisors) teeth [97 (41%) teeth]. Conclusions The technical quality of root canal filling performed by dental practitioners in a Turkish subpopulation was consistent with a high prevalence of AP. The probable reasons for this failure are multifactorial, and there may be a need for improved undergraduate education and postgraduate courses to improve the clinical skills of dental practitioners in endodontics. PMID:25591019

  8. Direct nano-patterning of graphene with helium ion beams

    SciTech Connect

    Naitou, Y.; Iijima, T.; Ogawa, S.

    2015-01-19

    Helium ion microscopy (HIM) was used for direct nano-patterning of single-layer graphene (SLG) on SiO{sub 2}/Si substrates. This technique involves irradiation of the sample with accelerated helium ions (He{sup +}). Doses of 2.0 × 10{sup 16 }He{sup + }cm{sup −2} from a 30 kV beam induced a metal-insulator transition in the SLG. The resolution of HIM patterning on SLG was investigated by fabricating nanoribbons and nanostructures. Analysis of scanning capacitance microscopy measurements revealed that the spatial resolution of HIM patterning depended on the dosage of He{sup +} in a non-monotonic fashion. Increasing the dose from 2.0 × 10{sup 16} to 5.0 × 10{sup 16 }He{sup + }cm{sup −2} improved the spatial resolution to several tens of nanometers. However, doses greater than 1.0 × 10{sup 17 }He{sup + }cm{sup −2} degraded the patterning characteristics. Direct patterning using HIM is a versatile approach to graphene fabrication and can be applied to graphene-based devices.

  9. Simulating discrete models of pattern formation by ion beam sputtering.

    PubMed

    Hartmann, Alexander K; Kree, Reiner; Yasseri, Taha

    2009-06-03

    A class of simple, (2+1)-dimensional, discrete models is reviewed, which allow us to study the evolution of surface patterns on solid substrates during ion beam sputtering (IBS). The models are based on the same assumptions about the erosion process as the existing continuum theories. Several distinct physical mechanisms of surface diffusion are added, which allow us to study the interplay of erosion-driven and diffusion-driven pattern formation. We present results from our own work on evolution scenarios of ripple patterns, especially for longer timescales, where nonlinear effects become important. Furthermore we review kinetic phase diagrams, both with and without sample rotation, which depict the systematic dependence of surface patterns on the shape of energy depositing collision cascades after ion impact. Finally, we discuss some results from more recent work on surface diffusion with Ehrlich-Schwoebel barriers as the driving force for pattern formation during IBS and on Monte Carlo simulations of IBS with codeposition of surfactant atoms.

  10. Genetic types of natural gas and filling patterns in Daniudi gas field, Ordos Basin, China

    NASA Astrophysics Data System (ADS)

    Liu, Quanyou; Jin, Zhijun; Meng, Qingqiang; Wu, Xiaoqi; Jia, Huichong

    2015-08-01

    The genetic types, source precursors and filling pattern of natural gas in the Upper Carboniferous Taiyuan Formation, Lower Permian Shanxi Formation and Lower Shihezi Formation gas reservoirs of Daniudi gas field were investigated using chemical composition as well as carbon and hydrogen isotopic compositions. Geochemical analysis of natural gases in 25 representative wells shows that natural gas in the Daniudi gas field is composed predominantly of hydrocarbons with a dryness coefficient of 0.884-0.978. The carbon isotopic values of ethane and propane are higher than -28‰ and -25‰, respectively, and the hydrogen isotopic values of methane are lower than -180‰, indicating that natural gas in the Daniudi field is a typical coal-type gas, derived mainly from humic organic matter in the transitional facies of the Carboniferous-Permian age. Hydrogen isotopic values of CH4 and H2 display a good positive correlation, suggesting that both were controlled by thermal maturity. When the mixing of ethane generated from mudstone and coal with the same kerogen type and similar thermal maturity occurred, the carbon isotopic values of ethane barely reflect the thermal maturity. Although the fractionation of hydrogen isotopes of ethane is significantly higher than that of carbon, hydrogen isotopic values of ethane in natural gas reservoirs evidently are not related to thermal maturity. The Daniudi natural gas reservoirs represent both self-sourced and near-source accumulations. The natural gas accumulations in the Late Triassic-Early Jurassic periods are mainly of the self-sourced type, while accumulations in the Late Jurassic-Early Cretaceous period comprise both self-sourced and near-source patterns, and the natural gas reservoirs formed after the Late Cretaceous period are mainly of the near-source type.

  11. Pattern formation during healing of fluid-filled cracks: an analog experiment

    SciTech Connect

    F. Renard; D. K. Dysthe; J. G. Feder; Paul Meakin; S.J.S. Morris; B. Jamtveit

    2009-11-01

    The formation and subsequent healing of cracks and crack networks may control such diverse phenomena as the strengthening of fault zones between earthquakes, fluid migrations in the Earth's crust, or the transport of radioactive materials in nuclear waste disposal. An intriguing pattern-forming process can develop during healing of fluid-filled cracks, where pockets of fluid remain permanently trapped in the solid as the crack tip is displaced driven by surface energy. Here, we present the results of analog experiments in which a liquid was injected into a colloidal inorganic gel to obtain penny-shaped cracks that were subsequently allowed to close and heal under the driving effect of interfacial tension. Depending on the properties of the gel and the injected liquid, two modes of healing were obtained. In the first mode, the crack healed completely through a continuous process. The second mode of healing was discontinuous and was characterized by a 'zipper-like' closure of a front that moved along the crack perimeter, trapping fluid that may eventually form inclusions trapped in the solid. This instability occurred only when the velocity of the crack tip decreased to zero. Our experiments provide a cheap and simple analog to reveal how aligned arrays of fluid inclusions may be captured along preexisting fracture planes and how small amounts of fluids can be permanently trapped in solids, modifying irreversibly their material properties.

  12. Atomistic simulation of ion beam patterning with crater functions

    NASA Astrophysics Data System (ADS)

    Yang, Zhangcan; Lively, Michael; Allain, Jean Paul

    2013-07-01

    In this study, an atomistic model is developed to simulate ripple pattern formation when a surface is irradiated by incident low-energy energetic ions. The model treats individual ion impacts using crater functions, which represent the average change in the surface shape due to a single-ion impact. These functions incorporate the complete redistribution of mass along the surface due to an impact, and not just that due to sputtering. While most models only treat erosion, analysis of the craters reveals that the amount of mass redistributed across the surface is an order of magnitude greater than the mass removed by sputtering. Simulations in this study are conducted for 500 eV Ar+ bombardments of Si at angles of 0° to 60° with 5° increment at temperature of 350 K. Initial simulations with this model have shown agreement with prior observations of ripple pattern formation. However, some significant departures from other models based on the Bradley-Harper theory have emerged; the key difference is that the presence of crater rims plays a key role in ripple formation, which could explain phenomena such as maximum ripple amplitudes which most models do not account for. These results show that atomistic crater functions are a viable method for modeling ion beam patterning. They indicate that mass redistribution is a key mechanism for surface patterning.

  13. Early hot electrons generation and beaming in ICF gas filled hohlraums at the National Ignition Facility

    NASA Astrophysics Data System (ADS)

    Dewald, Eduard; Michel, Pierre; Hartemann, Fred; Milovich, Jose; Hohenberger, Matthias; Divol, Laurent; Landen, Otto; Pak, Arthur; Thomas, Cliff; Doeppner, Tilo; Bachmann, Benjamin; Meezan, Nathan; MacKinnon, Andrew; Hurricane, Omar; Callahan, Debbie; Hinkel, Denise; Edwards, John

    2015-11-01

    In laser driven hohlraum capsule implosions on the National Ignition Facility, supra-thermal hot electrons generated by laser plasma instabilities can preheat the capsule. Time resolved hot electron Bremsstrahlung spectra combined with 30 keV x-ray imaging uncover for the first time the directionality of hot electrons onto a high-Z surrogate capsule located at the hohlraum center. In the most extreme case, we observed a collimated beaming of hot electrons onto the capsule poles, reaching 50x higher localized energy deposition than for isotropic electrons. A collective SRS model where all laser beams in a cone drive a common plasma wave provides a physical interpretation for the observed beaming. Imaging data are used to distinguish between this mechanism and 2ωp instability. The amount of hot electrons generated can be controlled by the laser pulse shape and hohlraum plasma conditions. This work performed under the auspices of the U.S. DOE by LLNL under Contract DE-AC52-07NA27344.

  14. Magnetic strip patterns induced by focused ion beam irradiation

    SciTech Connect

    Makarov, D.; Tibus, S.; Rettner, C. T.; Thomson, T.; Terris, B. D.; Schrefl, T.; Albrecht, M.

    2008-03-15

    Focused ion beam exposure was used to locally alter the magnetic properties of a continuous Co/Pd multilayer film with perpendicular magnetic anisotropy. The saturation magnetization, coercivity, and magnetic anisotropy of the films can be tuned by Ga irradiation depending on exposure dose. As a result, a periodic strip pattern consisting of 80 nm wide exposed strips which are magnetically soft, separated by 170 nm wide magnetically hard, unexposed areas was created. Due to strong magnetostatic coupling between the strips, a number of magnetic domain configurations could be stabilized and these have been observed by magnetic force microscopy and magneto-optic Kerr effect measurements. The magnetic domain configurations and their reversal behavior were investigated by micromagnetic simulations as a function of exposure dose and strip period.

  15. Localized plateau beam resulting from strong nonlocal coupling in a cavity filled by metamaterials and liquid-crystal cells

    NASA Astrophysics Data System (ADS)

    Tlidi, M.; Fernandez-Oto, C.; Clerc, M. G.; Escaff, D.; Kockaert, P.

    2015-11-01

    We investigate the formation of a localized plateau beam in the transverse section of a nonlinear optical ring cavity filled with a metamaterial and a nonlocal medium such as a nematic liquid crystal. We show that, far from the modulational instability regime, localized structures with a varying width may be stable in one and two-dimensional settings. The mechanism of stabilization is related with strong nonlocal coupling mediated by a Lorentzian type of kernel. We show that there exists stable bright and dark localized structures. A reduction of Lugiato-Lefever equation in the regime close to the nascent bistability allows us to analytically derive a simple formula for the width of localized structures in one-dimensional systems. Direct numerical simulations of the dynamical model agree with the analytical predictions.

  16. Studies of a Gas-filled Helical Muon Beam Cooling Channel

    SciTech Connect

    R.P. Johnson; K. Paul; T.J. Roberts; Y.S. Derbenev; K. Yonehara

    2006-06-26

    A helical cooling channel (HCC) can quickly reduce the six dimensional phase space of muon beams for muon colliders, neutrino factories, and intense muon sources. The HCC is composed of solenoidal, helical dipole, and helical quadrupole magnetic fields to provide the focusing and dispersion needed for emittance exchange as the beam follows an equilibrium helical orbit through a continuous homogeneous absorber. We consider liquid helium and liquid hydrogen absorbers in HCC segments that alternate with RF accelerating sections and we also consider gaseous hydrogen absorber in pressurized RF cavities imbedded in HCC segments. In the case of liquid absorber, the possibility of using superconducting RF in low magnetic field regions between the HCC segments may provide a cost effective solution to the high repetition rate needed for an intense neutrino factory or high average luminosity muon collider. In the gaseous hydrogen absorber case, the pressurized RF cavities can be operated at low temperature to improve their efficiency for higher repetition rates. Numerical simulations are used to optimize and compare the liquid and gaseous HCC techniques.

  17. 32 nm imprint masks using variable shape beam pattern generators

    NASA Astrophysics Data System (ADS)

    Selinidis, Kosta; Thompson, Ecron; Schmid, Gerard; Stacey, Nick; Perez, Joseph; Maltabes, John; Resnick, Douglas J.; Yeo, Jeongho; Kim, Hoyeon; Eynon, Ben

    2008-05-01

    Imprint lithography has been included on the ITRS Lithography Roadmap at the 32, 22 and 16 nm nodes. Step and Flash Imprint Lithography (S-FIL ®) is a unique method that has been designed from the beginning to enable precise overlay for creating multilevel devices. A photocurable low viscosity monomer is dispensed dropwise to meet the pattern density requirements of the device, thus enabling imprint patterning with a uniform residual layer across a field and across entire wafers. Further, S-FIL provides sub-100 nm feature resolution without the significant expense of multi-element, high quality projection optics or advanced illumination sources. However, since the technology is 1X, it is critical to address the infrastructure associated with the fabrication of templates. For sub-32 nm device manufacturing, one of the major technical challenges remains the fabrication of full-field 1x templates with commercially viable write times. Recent progress in the writing of sub-40 nm patterns using commercial variable shape e-beam tools and non-chemically amplified resists has demonstrated a very promising route to realizing these objectives, and in doing so, has considerably strengthened imprint lithography as a competitive manufacturing technology for the sub 32nm node. Here we report the first imprinting results from sub-40 nm full-field patterns, using Samsung's current flash memory production device design. The fabrication of the template is discussed and the resulting critical dimension control and uniformity are discussed, along with image placement results. The imprinting results are described in terms of CD uniformity, etch results, and overlay.

  18. An investigation of acoustic beam patterns for the sonar localization problem using a beam based method.

    PubMed

    Guarato, Francesco; Windmill, James; Gachagan, Anthony; Harvey, Gerald

    2013-06-01

    Target localization can be accomplished through an ultrasonic sonar system equipped with an emitter and two receivers. Time of flight of the sonar echoes allows the calculation of the distance of the target. The orientation can be estimated from knowledge of the beam pattern of the receivers and the ratio, in the frequency domain, between the emitted and the received signals after compensation for distance effects and air absorption. The localization method is described and, as its performance strongly depends on the beam pattern, the search of the most appropriate sonar receiver in order to ensure the highest accuracy of target orientation estimations is developed in this paper. The structure designs considered are inspired by the ear shapes of some bat species. Parameters like flare rate, truncation angle, and tragus are considered in the design of the receiver structures. Simulations of the localization method allow us to state which combination of those parameters could provide the best real world implementation. Simulation results show the estimates of target orientations are, in the worst case, 2° with SNR = 50 dB using the receiver structure chosen for a potential practical implementation of a sonar system.

  19. Effect of Beam Smoothing and Pulse Shape on the Implosion of DD-Filled CH Shell Targets on OMEGA

    NASA Astrophysics Data System (ADS)

    Delettrez, J. A.; Glebov, V. Yu.; Marshall, F. J.; Stoeckl, C.; Yaakobi, B.; Meyerhofer, D. D.

    1999-11-01

    Over the past two years several implosion experiments were carried out on the 60-beam OMEGA laser in which DD-filled CH shells (some with a CHTi layer imbedded) were irradiated with various laser pulse shapes and smoothing conditions. Target CH shell thicknesses varied from 20 μm to 27 μm with DD-fill variations from 3 to 20 atm, sometimes mixed with ^3He. Two pulse shapes---a 1-ns square pulse and a 2.5-ns pulse with a 10%, 1-ns foot, with and without SSD---provide several levels of laser imprint. Diagnostics include measured neutron yields, fuel ion temperatures, fuel ρR, and shell ρR. Simulations for these experimental conditions were carried out with the 2-D hydrocode ORCHID. The results are compared with the experimental results. The degradation of target performance due to laser nonuniformity is analyzed by comparing the 2-D results with those of 1-D simulations. The effects of pulse shape, target thickness, convergence ratio, and smoothing are presented. This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC03-92SF19460, the University of Rochester, and the New York State Energy Research and Development Authority.

  20. Radiant exposure level comparison between Gaussian and top hat beams in various scanning patterns.

    PubMed

    U-Thainual, Paweena; Yang, Yi; Le, Hanh N D; Kim, Do-Hyun

    2014-12-20

    The radiant exposure of optical irradiation beams with different scanning parameters has been theoretically studied. We analyzed the difference in radiant exposure introduced by Gaussian and top hat beams. Various parameters such as scanning pattern, aperture position, beam size and scan spacing were also introduced in this study. We found that Gaussian beams introduce higher calculated radiant exposure to the aperture than top hat beams for certain beam size to aperture size ratios. However, as the scan spacing decreases, the radiant exposure difference calculated from Gaussian and top hat beams diminishes.

  1. High Pressure Gas Filled RF Cavity Beam Test at the Fermilab MuCool Test Area

    SciTech Connect

    Freemire, Ben

    2013-05-01

    The high energy physics community is continually looking to push the limits with respect to the energy and luminosity of particle accelerators. In the realm of leptons, only electron colliders have been built to date. Compared to hadrons, electrons lose a large amount of energy when accelerated in a ring through synchrotron radiation. A solution to this problem is to build long, straight accelerators for electrons, which has been done with great success. With a new generation of lepton colliders being conceived, building longer, more powerful accelerators is not the most enticing option. Muons have been proposed as an alternative particle to electrons. Muons lose less energy to synchrotron radiation and a Muon Collider can provide luminosity within a much smaller energy range than a comparable electron collider. This allows a circular collider to be built with higher attainable energy than any present electron collider. As part of the accelerator, but separate from the collider, it would also be possible to allow the muons to decay to study neutrinos. The possibility of a high energy, high luminosity muon collider and an abundant, precise source of neutrinos is an attractive one. The technological challenges of building a muon accelerator are many and diverse. Because the muon is an unstable particle, a muon beam must be cooled and accelerated to the desired energy within a short amount of time. This requirement places strict requisites on the type of acceleration and focusing that can be used. Muons are generated as tertiary beams with a huge phase space, so strong magnetic fields are required to capture and focus them. Radio frequency (RF) cavities are needed to capture, bunch and accelerate the muons. Unfortunately, traditional vacuum RF cavities have been shown to break down in the magnetic fields necessary for capture and focusing.

  2. E-beam-patterned hydrogels to control nanoscale surface bioactivity

    NASA Astrophysics Data System (ADS)

    Krsko, P.; Saaem, I.; Clancy, R.; Geller, H.; Soteropoulos, P.; Libera, M.

    2005-11-01

    We are interested in controlling the spatial distribution of proteins on surfaces at cellular and subcellular length scales. To do this, we use a variation of e-beam lithography in a field-emission scanning electron microscope (SEM) to radiation crosslink thin films of water- soluble polymers such as poly(ethylene glycol) [PEG] and poly (carboxylic acids). We can simultaneously pattern the resulting hydrogels on silicon or glass surfaces with nanoscale and microscale feature sizes. Using hydroxy-terminated PEG 6800 we create gels with swell ratios between unity and fifteen depending on the degree of radiation crosslinking, and the swelling properties can be interpreted in terms of the Flory-Rehner formulation modified for one-dimensional swelling. While lightly-crosslinked PEG gels resist protein adsorption and cell adhesion as expected, highly crosslinked PEG gels adsorb such proteins as fibronectin and laminin and consequently become adhesive to fibroblasts, macrophages, and neurons. By spatially modulating the degree of crosslinking, we can localize these cells on surfaces and, for example, direct neurite outgrowth. If instead of using hydroxy-terminated PEG we use amine- terminated PEG, we introduce the additional flexibility of creating high-swelling PEG gels that resist nonspecific protein adsorption but to which specific proteins can be covalently bound. These can be surface patterned at submicron spacings, and we can pattern 7500 nanohydrogels in a 100 micron diameter arrays in 10 seconds. This is an areal density ~104 times greater than a modern DNA/protein chip, and the required bioreagents for chip fabrication and processing are proportionately less. We can bind fibronectin and laminin to different arrays, and we show that these proteins maintain their biospecificity after binding to the nanohydrogels with high fidelity. Looking to applications in next-generation protein-chip technology, our most recent experiments compare the performance of nanohydrogel

  3. Impact of Non-Uniform Beam Filling on Spaceborne Cloud and Precipitation Radar Retrieval Algorithms

    NASA Technical Reports Server (NTRS)

    Tanelli, Simone; Sacco, Gian Franco; Durden, Stephen L.; Haddad, Ziad S.

    2012-01-01

    In this presentation we will discuss the performance of classification and retrieval algorithms for spaceborne cloud and precipitation radars such as the Global Precipitation Measurement mission Dual-frequency Precipitation Radar (GPM/DPR), and notional radar for the Aerosol/Clouds/Ecosystem (ACE) mission and related concepts. Spaceborne radar measurements are simulated either from Airborne Precipitation Radar 2nd Generation observations, or from atmospheric model outputs via instrument simulators contained in the NASA Earth Observing Systems Simulators Suite (NEOS(sup 3)). Both methods account for the three dimensional nature of the scattering field at resolutions smaller than that of the spaceborne radar under consideration. We will focus on the impact of non-homogeneities of the field of hydrometeors within the beam. We will discuss also the performance of methods to identify and mitigate such conditions, and the resulting improvements in retrieval accuracy. The classification and retrieval algorithms analyzed in this study are those derived from APR-2's Suite of Processing and Retrieval Algorithms (ASPRA); here generalized to operate on an arbitrary set of radar configuration parameters to study the expected performance of spaceborne cloud and precipitation radars. The presentation will highlight which findings extend to other algorithm families and which ones do not.

  4. Controllable Airy-like beams induced by tunable phase patterns

    NASA Astrophysics Data System (ADS)

    Li, D.; Qian, Y.

    2016-01-01

    We propose and experimentally observe a novel family of Airy-like beams. First, we theoretically investigate the physical generation of our proposed controllable Airy-like beams by introducing a rotation angle factor into the phase function, which can regulate and flexibly control the beam wavefront. Meanwhile we can also readily control the main lobes of these beams to follow appointed parabolic trajectories using the rotation angle factor. We also demonstrate that the controllable Airy-like beams lack the properties of being diffraction-free and self-healing. The experiments are performed and the results are in accord with the theoretical simulations. We believe that the intriguing characteristics of our proposed Airy-like beams could provide more degrees of freedom, and are likely to give rise to new applications and lend versatility to the emerging field.

  5. Ecloud Build-Up Simulations for the FNAL MI for a Mixed Fill Pattern: Dependence on Peak SEY and Pulse Intensity During the Ramp

    SciTech Connect

    Furman, M. A.

    2010-12-11

    We present simulation results of the build-up of the electron-cloud density n{sub e} in three regions of the FNAL Main Injector (MI) for a beam fill pattern made up of 5 double booster batches followed by a 6th single batch. We vary the pulse intensity in the range N{sub t} = (2-5) x 10{sup 13}, and the beam kinetic energy in the range E{sub k} = 8-120 GeV. We assume a secondary electron emission model qualitatively corresponding to TiN, except that we let the peak value of the secondary electron yield (SEY) {delta}{sub max} vary as a free parameter in a fairly broad range. Our main conclusions are: (1) At fixed N{sub t} there is a clear threshold behavior of n{sub e} as a function of {delta}{sub max} in the range {approx} 1.1-1.3. (2) At fixed {delta}{sub max}, there is a threshold behavior of n{sub e} as a function of N{sub t} provided {delta}{sub max} is sufficiently high; the threshold value of N{sub t} is a function of the characteristics of the region being simulated. (3) The dependence on E{sub k} is weak except possibly at transition energy. Most of these results were informally presented to the relevant MI personnel in April 2010.

  6. Nano- and Micro-Structured UHMWPE Composites Filled With Hydroxyapatite Irradiated by Nitrogen Ion Beams for Bio-Medical Applications

    NASA Astrophysics Data System (ADS)

    Panin, S. V.; Kornienko, L. A.; Chaikina, M. V.; Sergeev, V. P.; Ivanova, L. R.; Shilko, S. V.

    2014-02-01

    The effect of filling the ultra-high-molecular-weight polyethylene (UHMWPE) with nano- and microparticles of hydroxyapatite (HA) on its structure and tribotechnical properties is investigated, aiming at application of the modified UHMWPE in endoprosthetics. An introduction of 0.1-0.5 wt% HA nanoparticles into UHMWPE is shown to result in a threefold increase in its wear resistance. A similar effect is observed in the case where 20 wt% of HA microparticles is used. Treatment of the surface of nano- and microcomposites with a nitrogen ion beam increases the wear resistance by an additional 10-30%. A combined treatment of UHMWPE powder and fillers in a planetary ball mill leads to a uniform distribution of the latter in the polymer matrix and, consequently, to the formation of a more ordered permolecular structure. In the irradiated UHMWPE micro- and nanocomposites reinforced with HA, the tribotechnical properties are shown to improve due to the formation of new chemical bonds (primarily via cross-linking) and ordered permolecular structure.

  7. Panel zone behavior of moment connections between rectangular concrete-filled steel tubes and wide flange beams

    NASA Astrophysics Data System (ADS)

    Koester, Bradley Donald

    2000-10-01

    During the 1990s, guidelines for the detailing of composite joints for seismic safety have been proposed and adopted. Such guidelines were based on the testing of composite joint subassemblies under cyclic loads. The role of the confined concrete core in composite joints has been documented and quantified for systems using steel shapes encased in concrete, as well as for other mixtures of reinforced concrete and structural steel. The need to understand the role of the concrete core in moment connections utilizing concrete-fined tube (CFT) columns still exists. In this research program, the split-tee through-bolted moment connection between wide-flange steel beams and concrete-filled tubes was studied. The aim of the study was to understand the role of the confined concrete core in transferring forces through the joint. Fifteen half-scale panel-zone specimens were designed and tested to model the shear behavior of the split-tee connection. Following an analysis of the results of the panel-zone tests, six fun-scale moment connections were designed and tested. Variables studied were: concrete compressive strength, the b/t ratio (slenderness) of the steel tube walls, and the split-tee contact area against the steel tube. Following an analysis of the test data, design criteria for the concrete contribution to the joint strength are presented, and recommendations are made for the inclusion of CFT systems in the design recommendations for composite joints. Suggestions are made for further research.

  8. External Beam Radiotherapy for Colon Cancer: Patterns of Care

    SciTech Connect

    Dunn, Emily F.; Kozak, Kevin R.; Moody, John S.

    2010-04-15

    Purpose: Despite its common and well characterized use in other gastrointestinal malignancies, little is known about radiotherapy (RT) use in nonmetastatic colon cancer in the United States. To address the paucity of data regarding RT use in colon cancer management, we examined the RT patterns of care in this patient population. Methods and Materials: Patients with nonmetastatic colon cancer, diagnosed between 1988 and 2005, were identified in the Surveillance, Epidemiology, and End Results (SEER) database. Univariate and multivariate methods were used to identify factors associated with RT use. Results: On univariate analysis, tumor location, age, sex, race, T stage, N stage, and geographic location were each associated with differences in RT use (all p < 0.01). In general, younger patients, male patients, and patients with more advanced disease were more likely to receive RT. On multivariate analysis, tumor location, age, gender, T and N stage, time of diagnosis and geographic location were significantly associated with RT use (all p < 0.001). Race, however, was not associated with RT use. On multivariate analysis, patients diagnosed in 1988 were 2.5 times more likely to receive RT than those diagnosed in 2005 (p = 0.001). Temporal changes in RT use reflect a responsiveness to evolving evidence related to the therapeutic benefits of adjuvant RT. Conclusions: External beam RT is infrequently used for colon cancer, and its use varies according to patient and tumor characteristics. RT use has declined markedly since the late 1980s; however, it continues to be used for nonmetastatic disease in a highly individualized manner.

  9. High resolution acoustic measurement system and beam pattern reconstruction method for bat echolocation emissions.

    PubMed

    Gaudette, Jason E; Kloepper, Laura N; Warnecke, Michaela; Simmons, James A

    2014-01-01

    Measurements of the transmit beam patterns emitted by echolocating bats have previously been limited to cross-sectional planes or averaged over multiple signals using sparse microphone arrays. To date, no high-resolution measurements of individual bat transmit beams have been reported in the literature. Recent studies indicate that bats may change the time-frequency structure of their calls depending on the task, and suggest that their beam patterns are more dynamic than previously thought. To investigate beam pattern dynamics in a variety of bat species, a high-density reconfigurable microphone array was designed and constructed using low-cost ultrasonic microphones and custom electronic circuitry. The planar array is 1.83 m wide by 1.42 m tall with microphones positioned on a 2.54 cm square grid. The system can capture up to 228 channels simultaneously at a 500 kHz sampling rate. Beam patterns are reconstructed in azimuth, elevation, and frequency for visualization and further analysis. Validation of the array measurement system and post-processing functions is shown by reconstructing the beam pattern of a transducer with a fixed circular aperture and comparing the result with a theoretical model. To demonstrate the system in use, transmit beam patterns of the big brown bat, Eptesicus fuscus, are shown.

  10. The requirements for the future e-beam mask writer: statistical analysis of pattern accuracy

    NASA Astrophysics Data System (ADS)

    Lee, Sang Hee; Choi, Jin; Kim, Hee Bom; Kim, Byung Gook; Cho, Han-Ku

    2011-11-01

    As semiconductor features shrink in size and pitch, the extreme control of CD uniformity, MTT and image placement is needed for mask fabrication with e-beam lithography. Among the many sources of CD and image placement error, the error resulting from e-beam mask writer becomes more important than before. CD and positioning error by e-beam mask writer is mainly related to the imperfection of e-beam deflection accuracy in optic system and the charging and contamination of column. To avoid these errors, the e-beam mask writer should be designed taking into account for these effects. However, the writing speed is considered for machine design with the highest priority, because the e-beam shot count is increased rapidly due to design shrink and aggressive OPC. The increment of shot count can make the pattern shift problem due to statistical issue resulting from e-beam deflection error and the total shot count in layout. And it affects the quality of CD and image placement too. In this report, the statistical approach on CD and image placement error caused by e-beam shot position error is presented. It is estimated for various writing conditions including the intrinsic e-beam positioning error of VSB writer. From the simulation study, the required e-beam shot position accuracy to avoid pattern shift problem in 22nm node and beyond is estimated taking into account for total shot count. And the required local CD uniformity is calculated for various e-beam writing conditions. The image placement error is also simulated for various conditions including e-beam writing field position error. Consequently, the requirements for the future e-beam mask writer and the writing conditions are discussed. And in terms of e-beam shot noise, LER caused by exposure dose and shot position error is studied for future e-beam mask writing for 22nm node and beyond.

  11. Pilot Beam Pattern Design for Channel Estimation in Massive MIMO Systems

    NASA Astrophysics Data System (ADS)

    Noh, Song; Zoltowski, Michael D.; Sung, Youngchul; Love, David J.

    2014-10-01

    In this paper, the problem of pilot beam pattern design for channel estimation in massive multiple-input multiple-output systems with a large number of transmit antennas at the base station is considered, and a new algorithm for pilot beam pattern design for optimal channel estimation is proposed under the assumption that the channel is a stationary Gauss-Markov random process. The proposed algorithm designs the pilot beam pattern sequentially by exploiting the properties of Kalman filtering and the associated prediction error covariance matrices and also the channel statistics such as spatial and temporal channel correlation. The resulting design generates a sequentially-optimal sequence of pilot beam patterns with low complexity for a given set of system parameters. Numerical results show the effectiveness of the proposed algorithm.

  12. Ion-beam nano-patterning by using porous anodic alumina as a mask

    NASA Astrophysics Data System (ADS)

    Shin, S. W.; Lee, S. G.; Lee, J.; Whang, C. N.; Lee, J.-H.; Choi, I.-H.; Kim, T. G.; Song, J. H.

    2005-08-01

    Anodized aluminium oxide (AAO) with self-organized and ordered nano-hole arrays may be a good candidate for an irradiation mask to modify the properties of a nano-scale region. In order to use AAO as a mask for ion beam patterning, the ion beam transmittance of AAO should first be tested. In an AAO with a high aspect ratio (about 100), anodized from Al bulk foil, the ion beam transmittance was extremely low. However, when AAO with low aspect ratio (about 5), fabricated with thin film Al on SiO2, was irradiated with 80 keV Co ions, the Co ion transmittance was enormously improved. After selective etching of the unirradiated region, ion beam patterned 80 nm SiO2 dot arrays have been fabricated. This shows a potential of AAO with a low aspect ratio for an ion beam patterning nano-mask. In order to demonstrate the ion beam nano-patterning, magnetic nano-patterning was performed. A Co/Pt multilayer film with a perpendicular magnetic anisotropy was ion irradiated through an AAO mask with a low aspect ratio, 460 nm height and 50 nm diameter, and the magnetic properties were investigated by MOKE. The formation of a magnetic nano-pattern was confirmed by MFM.

  13. Design of a bullet beam pattern of a micro ultrasound transducer (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Roh, Yongrae; Lee, Seongmin

    2016-04-01

    Ultrasonic imaging transducer is often required to compose a beam pattern of a low sidelobe level and a small beam width over a long focal region to achieve good image resolution. Normal ultrasound transducers have many channels along its azimuth, which allows easy formation of the sound beam into a desired shape. However, micro-array transducers have no control of the beam pattern along their elevation. In this work, a new method is proposed to manipulate the beam pattern by using an acoustic multifocal lens and a shaded electrode on top of the piezoelectric layer. The shading technique split an initial uniform electrode into several segments and combined those segments to compose a desired beam pattern. For a given elevation width and frequency, the optimal pattern of the split electrodes was determined by means of the OptQuest-Nonlinear Program (OQ-NLP) algorithm to achieve the lowest sidelobe level. The requirement to achieve a small beam width with a long focal region was satisfied by employing an acoustic lens of three multiple focuses. Optimal geometry of the multifocal lens such as the radius of curvature and aperture diameter for each focal point was also determined by the OQ-NLP algorithm. For the optimization, a new index was devised to evaluate the on-axis response: focal region ratio = focal region / minimum beam width. The larger was the focal region ratio, the better was the beam pattern. Validity of the design has been verified through fabricating and characterizing an experimental prototype of the transducer.

  14. Image reversal for direct electron beam patterning of protein coated surfaces.

    PubMed

    Pesen, Devrim; Erlandsson, Anna; Ulfendahl, Mats; Haviland, David B

    2007-11-01

    Electron beam lithography (EBL) is used to create surfaces with protein patterns, which are characterized by immunofluorescence and atomic force microscopies. Both negative and positive image processes are realized by electron beam irradiation of proteins absorbed on a silicon surface, where image reversal is achieved by selectively binding a second species of protein to the electron beam exposed areas on the first protein layer. Biofunctionality at the cellular level was established by culturing cortical cells on patterned lines of fibronectin adsorbed on a bovine serum albumin background for 7 days in culture.

  15. Generation of Homogeneous and Patterned Electron Beams using a Microlens Array Laser-Shaping Technique

    SciTech Connect

    Halavanau, Aliaksei; Edstrom, Dean; Gai, Wei; Ha, Gwanghui; Piot, Philippe; Power, John; Qiang, Gao; Ruan, Jinhao; Santucci, James; Wisniewski, Eric

    2016-06-01

    In photocathodes the achievable electron-beam parameters are controlled by the laser used to trigger the photoemission process. Non-ideal laser distribution hampers the final beam quality. Laser inhomogeneities, for instance, can be "amplified" by space-charge force and result in fragmented electron beams. To overcome this limitation laser shaping methods are routinely employed. In the present paper we demonstrate the use of simple microlens arrays to dramatically improve the transverse uniformity. We also show that this arrangement can be used to produce transversely-patterned electron beams. Our experiments are carried out at the Argonne Wakefield Accelerator facility.

  16. Argon ion beam induced surface pattern formation on Si

    SciTech Connect

    Hofsäss, H.; Bobes, O.; Zhang, K.

    2016-01-21

    The development of self-organized surface patterns on Si due to noble gas ion irradiation has been studied extensively in the past. In particular, Ar ions are commonly used and the pattern formation was analyzed as function of ion incidence angle, ion fluence, and ion energies between 250 eV and 140 keV. Very few results exist for the energy regime between 1.5 keV and 10 keV and it appears that pattern formation is completely absent for these ion energies. In this work, we present experimental data on pattern formation for Ar ion irradiation between 1 keV and 10 keV and ion incidence angles between 50° and 75°. We confirm the absence of patterns at least for ion fluences up to 10{sup 18} ions/cm{sup 2}. Using the crater function formalism and Monte Carlo simulations, we calculate curvature coefficients of linear continuum models of pattern formation, taking into account contribution due to ion erosion and recoil redistribution. The calculations consider the recently introduced curvature dependence of the erosion crater function as well as the dynamic behavior of the thickness of the ion irradiated layer. Only when taking into account these additional contributions to the linear theory, our simulations clearly show that that pattern formation is strongly suppressed between about 1.5 keV and 10 keV, most pronounced at 3 keV. Furthermore, our simulations are now able to predict whether or not parallel oriented ripple patterns are formed, and in case of ripple formation the corresponding critical angles for the whole experimentally studied energies range between 250 eV and 140 keV.

  17. Trehalose glycopolymer resists allow direct writing of protein patterns by electron-beam lithography.

    PubMed

    Bat, Erhan; Lee, Juneyoung; Lau, Uland Y; Maynard, Heather D

    2015-03-20

    Direct-write patterning of multiple proteins on surfaces is of tremendous interest for a myriad of applications. Precise arrangement of different proteins at increasingly smaller dimensions is a fundamental challenge to apply the materials in tissue engineering, diagnostics, proteomics and biosensors. Herein, we present a new resist that protects proteins during electron-beam exposure and its application in direct-write patterning of multiple proteins. Polymers with pendant trehalose units are shown to effectively crosslink to surfaces as negative resists, while at the same time providing stabilization to proteins during the vacuum and electron-beam irradiation steps. In this manner, arbitrary patterns of several different classes of proteins such as enzymes, growth factors and immunoglobulins are realized. Utilizing the high-precision alignment capability of electron-beam lithography, surfaces with complex patterns of multiple proteins are successfully generated at the micrometre and nanometre scale without requiring cleanroom conditions.

  18. Trehalose Glycopolymer Resists Allow Direct Writing of Protein Patterns by Electron-Beam Lithography

    PubMed Central

    Bat, Erhan; Lee, Juneyoung; Lau, Uland Y.; Maynard, Heather D.

    2015-01-01

    Direct-write patterning of multiple proteins on surfaces is of tremendous interest for a myriad of applications. Precise arrangement of different proteins at increasingly smaller dimensions is a fundamental challenge to apply the materials in tissue engineering, diagnostics, proteomics and biosensors. Herein we present a new resist that protects proteins during electron beam exposure and its application in direct-write patterning of multiple proteins. Polymers with pendant trehalose units are shown to effectively cross-link to surfaces as negative resists, while at the same time providing stabilization to proteins during the vacuum and electron beam irradiation steps. In this manner, arbitrary patterns of several different classes of proteins such as enzymes, growth factors and immunoglobulins are realized. Utilizing the high precision alignment capability of electron-beam lithography, surfaces with complex patterns of multiple proteins are successfully generated at the micrometer and nanometer scale without requiring cleanroom conditions. PMID:25791943

  19. Reference Beam Pattern Design for Frequency Invariant Beamforming Based on Fast Fourier Transform

    PubMed Central

    Zhang, Wang; Su, Tao

    2016-01-01

    In the field of fast Fourier transform (FFT)-based frequency invariant beamforming (FIB), there is still an unsolved problem. That is the selection of the reference beam to make the designed wideband pattern frequency invariant (FI) over a given frequency range. This problem is studied in this paper. The research shows that for a given array, the selection of the reference beam pattern is determined by the number of sensors and the ratio of the highest frequency to the lowest frequency of the signal (RHL). The length of the weight vector corresponding to a given reference beam pattern depends on the reference frequency. In addition, the upper bound of the weight length to ensure the FI property over the whole frequency band of interest is also given. When the constraints are added to the reference beam, it does not affect the FI property of the designed wideband beam as long as the symmetry of the reference beam is ensured. Based on this conclusion, a scheme for reference beam design is proposed. PMID:27669242

  20. Reference Beam Pattern Design for Frequency Invariant Beamforming Based on Fast Fourier Transform.

    PubMed

    Zhang, Wang; Su, Tao

    2016-09-22

    In the field of fast Fourier transform (FFT)-based frequency invariant beamforming (FIB), there is still an unsolved problem. That is the selection of the reference beam to make the designed wideband pattern frequency invariant (FI) over a given frequency range. This problem is studied in this paper. The research shows that for a given array, the selection of the reference beam pattern is determined by the number of sensors and the ratio of the highest frequency to the lowest frequency of the signal (RHL). The length of the weight vector corresponding to a given reference beam pattern depends on the reference frequency. In addition, the upper bound of the weight length to ensure the FI property over the whole frequency band of interest is also given. When the constraints are added to the reference beam, it does not affect the FI property of the designed wideband beam as long as the symmetry of the reference beam is ensured. Based on this conclusion, a scheme for reference beam design is proposed.

  1. Investigating the effect of electron emission pattern on RF gun beam quality

    NASA Astrophysics Data System (ADS)

    Rajabi, A.; Shokri, B.

    2016-05-01

    Thermionic radio frequency gun is one of the most promising choices to gain a high quality electron beam, used in the infrared free electron lasers and synchrotron radiation injectors. To study the quality of the beam in a compact electron source, the emission pattern effect on the beam dynamics should be investigated. In the presented work, we developed a 3D simulation code to model the real process of thermionic emission and to investigate the effect of emission pattern, by considering geometrical constraints, on the beam dynamics. According to the results, the electron bunch emittance varies considerably with the emission pattern. Simulation results have been validated via comparison with the well-known simulation codes such as ASTRA simulation code and CST microwave studio, as well as other simulation results in the literature. It was also demonstrated that by using a continuous wave laser beam for heating the cathode, the emission pattern full width at half maximum (FWHM) of the transverse emission distribution is proportional to FWHM of the Gaussian profile for the laser beam. Additionally, by using the developed code, the effect of wall structure around the cathode on the back bombardment effect has been studied. According to the results, for a stable operation of the RF gun, one should consider the nose cone in vicinity of the cathode surface to reduce the back-bombardment effect.

  2. Blister-free ion beam patterning of supported graphene

    NASA Astrophysics Data System (ADS)

    Herbig, Charlotte; Åhlgren, E. Harriet; Michely, Thomas

    2017-02-01

    Ion irradiation of metal supported two-dimensional layers results over a broad parameter space in noble gas trapping at the interface of the two-dimensional layer and the metal substrate. Trapping may give rise to the formation of gas filled blisters which deteriorate the structural and electronic properties of graphene. Here, we investigate the dependence of noble gas trapping at a graphene/Ir(111) interface and of graphene sputtering on the angle of incidence using scanning tunneling microscopy. Our experimental results are compared to dedicated molecular dynamics simulations. We find that at large impact angles of ≈ 80^\\circ graphene can be eroded without noble gas trapping and thereby establish conditions for nanopatterning without concomitant blister formation.

  3. Blister-free ion beam patterning of supported graphene.

    PubMed

    Herbig, Charlotte; Åhlgren, E Harriet; Michely, Thomas

    2017-02-03

    Ion irradiation of metal supported two-dimensional layers results over a broad parameter space in noble gas trapping at the interface of the two-dimensional layer and the metal substrate. Trapping may give rise to the formation of gas filled blisters which deteriorate the structural and electronic properties of graphene. Here, we investigate the dependence of noble gas trapping at a graphene/Ir(111) interface and of graphene sputtering on the angle of incidence using scanning tunneling microscopy. Our experimental results are compared to dedicated molecular dynamics simulations. We find that at large impact angles of [Formula: see text] graphene can be eroded without noble gas trapping and thereby establish conditions for nanopatterning without concomitant blister formation.

  4. Patterning of hyperbranched resist materials by e-beam

    NASA Astrophysics Data System (ADS)

    Trimble, Alexander R.; Tully, David C.; Frechet, Jean M. J.; Medeiros, David R.; Angelopoulos, Marie

    2000-06-01

    The application of a hyperbranched polymer with its globular architecture as a chemically amplified resist system is demonstrated. These hyperbranched poly(esters) based on 3,5- dihydroxybenzoic acid and 4,4-bis(4-hydroxyphenyl)valeric acid and obtained by a polycondensation process at high temperatures. Once obtained, the hyperbranched polymers are functionalized with acid and thermally labile t-BOC groups by reaction of their phenolic groups with di-t-butyl dicarbonate in the presence of a catalytic amount of potassium t-butoxide. These globular materials have number average molecular weights (Mn) in the range of 5,000 - 20,000 with polydispersities of 1.5 - 2. Exposure of the hyperbranched resist material formulated with a photoacid generator was carried out using a direct-write electron-beam (e-beam) tool operating at 50 keV with doses of 15 - 40 (mu) C/cm2. Development of these resist materials can be accomplished in either aqueous base developer or organic solvent, thereby allowing access to both the positive and negative tone images. Feature sizes of 100 nm are readily obtained from these unoptimized materials.

  5. Demonstration of electronic pattern switching and 10x pattern demagnification in a maskless micro-ion beam reduction lithography system

    NASA Astrophysics Data System (ADS)

    Ngo, V. V.; Akker, B.; Leung, K. N.; Noh, I.; Scott, K. L.

    2002-05-01

    A proof-of-principle ion projection lithography (IPL) system called Maskless Micro-ion beam Reduction Lithography (MMRL) has been developed and tested at the Lawrence Berkeley National Laboratory (LBNL) for future integrated circuits (ICs) manufacturing and thin film media patterning. This MMRL system is aimed at completely eliminating the first stage of the conventional IPL system that contains the complicated beam optics design in front of the stencil mask and the mask itself. It consists of a multicusp RF plasma generator, a multi-beamlet pattern generator, and an all-electrostatic ion optical column. Results from ion beam exposures on PMMA and Shipley UVII-HS resists using 75 keV H+ are presented in this paper. Proof-of-principle electronic pattern switching together with 10x reduction ion optics (using a pattern generator made of nine 50-(micro)m switchable apertures) has been performed and is reported in this paper. In addition, the fabrication of a micro-fabricated pattern generator on an SOI membrane is also presented.

  6. Mechanism of nanostructure movement under an electron beam and its application in patterning

    NASA Astrophysics Data System (ADS)

    Seminara, Agnese; Pokroy, Boaz; Kang, Sung H.; Brenner, Michael P.; Aizenberg, Joanna

    2011-06-01

    In electron microscopy, the motion of the sample features due to the interaction with the electron beam has been traditionally regarded as a detrimental effect. Uncontrolled feature displacement produces artifacts both in imaging and patterning, limiting the resolution and distorting precise nanoscale patterns. The mechanism of such motion remains largely unclear. We present an experimental study of e-beam-induced nanopost movement and offer a mechanistic theoretical model that quantitatively explains the physical phenomenon. We propose that e-beam bombardment produces an uneven distribution of electrons in the sample, and the resulting electrostatic interactions provide forces and torques sufficient to bend the nanoposts. We compare the theoretical predictions with a series of controlled experiments that support our model. We take advantage of this theoretical understanding to demonstrate how this generally undesirable effect can be turned into an unconventional e-beam writing technique to generate pseudo-three-dimensional structures.

  7. CO2 lasers: beam patterns in relation to surgical use.

    PubMed

    Fava, G; Emanuelli, H; Cascinelli, N; Bandieramonte, G; Canestri, F; Marchesini, R

    1983-01-01

    According to surgeons operating with a variety of CO2 lasers available at the National Cancer Institute of Milan (Coherent, Sharplan, Valfivre), these lasers have different cutting and coagulation properties. To identify what physical parameters might corroborate the subjective impression of the surgeons, a comparative study of the crater forms in perspex samples was performed. Perspex was chosen for its thermal properties (in fact, its thermal conductivity and diffusivity are similar to those of organic tissue) and because it allowed good visualization and measurement of crater characteristics. Depth of penetration, crater diameter, and extension of thermal damage were measured against power, focal length, and exposure time for each CO2 laser model. These results can be used as an index of behaviour of different surgical lasers. It appears that for fully characterizing the interaction of surgical lasers with the sample, it is necessary to specify either power, focal length, exposure time, or beam mode.

  8. Dye-impregnated polymer-filled porous glass: a new composite material for solid state dye lasers and laser beam control optical elements (Abstract Only)

    NASA Astrophysics Data System (ADS)

    Koldunov, M. F.; Manenkov, Alexander A.; Sitnikov, N. M.; Dolotov, S. M.

    1994-07-01

    Polymer-filled microporous glass (PFMG) composite materials have been recently proposed as a proper host for dyes to create solid-state dye lasers and laser beam control elements (Q-switchers, etc.) [1,2]. In this paper we report investigation of some laser-related properties of Polymethilmethacrylate (PMAA) - filled porous glass doped with Rhodamine 6G perchiorate (active lasing dye) and 1055 dye (passive bleachable dye): laser induced damage threshold, lasmg efficiency, bleaching efficiency, and microhardness have been measured. All these characteristics have been found to be rather high indicating that PFMG composite materials are perspective hosts for dye impregnation and fabrication highly effective solid-state dye lasers and other laser related elements (Q-switchers, mode-lockers, modeselectors, spatial filters).

  9. Simulation of electron beam formation and transport in a gas-filled electron-optical system with a plasma emitter

    NASA Astrophysics Data System (ADS)

    Grishkov, A. A.; Kornilov, S. Yu.; Rempe, N. G.; Shidlovskiy, S. V.; Shklyaev, V. A.

    2016-07-01

    The results of computer simulations of the electron-optical system of an electron gun with a plasma emitter are presented. The simulations are performed using the KOBRA3-INP, XOOPIC, and ANSYS codes. The results describe the electron beam formation and transport. The electron trajectories are analyzed. The mechanisms of gas influence on the energy inhomogeneity of the beam and its current in the regions of beam primary formation, acceleration, and transport are described. Recommendations for optimizing the electron-optical system with a plasma emitter are presented.

  10. The effect of residual gas scattering on Ga ion beam patterning of graphene

    SciTech Connect

    Thissen, Nick F. W. E-mail: a.a.bol@tue.nl; Vervuurt, R. H. J.; Weber, J. W.; Kessels, W. M. M.; Bol, A. A. E-mail: a.a.bol@tue.nl; Mulders, J. J. L.

    2015-11-23

    The patterning of graphene by a 30 kV Ga{sup +} focused ion beam (FIB) is studied by in-situ and ex-situ Raman spectroscopy. It is found that the graphene surrounding the patterned target area can be damaged at remarkably large distances of more than 10 μm. We show that scattering of the Ga ions in the residual gas of the vacuum system is the main cause of the large range of lateral damage, as the size and shape of the tail of the ion beam were strongly dependent on the system background pressure. The range of the damage was therefore greatly reduced by working at low pressures and limiting the total amount of ions used. This makes FIB patterning a feasible alternative to electron beam lithography as long as residual gas scattering is taken into account.

  11. The effect of energy deposition on pattern resolution in electron beam lithography

    NASA Astrophysics Data System (ADS)

    Raghunathan, Ananthan

    Electron beam lithography is one of the most important tools for nanofabrication. Electron beam lithography has consistently been able to offer higher resolution, typically better than 10 nm or so, compared to other techniques. In this work the contribution of electron-substrate interaction to pattern resolution is investigated. In electron beam lithography the incident beam is scattered in the resist-substrate stack by a combination of elastic and inelastic events which is described by the point spread function. Using a Vistec VB300 Gaussian beam lithography tool operating at 100 keV the experimental point spread function is investigated by a technique called point exposure distribution measurements. The experimental results indicate that the scattering in the sub-100 nm range shows several orders of the magnitude difference with that obtained via Monte Carlo simulations. In high energy electron beam lithography where forward scattering in small, contribution of secondary electrons generated by the primary beam must be taken into account. The chemical change leading to resist exposure is through bond scission, which is typically a low energy event between 3 -- 5 eV. Compared to the primary beam, the secondary electrons have a significantly higher probability of scission due to their lower energy. These secondary electrons are also generated with large emission angles and can travel several nanometers, leading to an increase in observed line widths compared to the size of the beam. An analytical model developed here, that considers the energy deposited by the secondary electrons, is able to predict the dependence of dose on observed diameter to within a reasonable accuracy. This technique used in conjunction with the knowledge of resist contrast is also indicative of pattern resolution limits in high energy electron beam lithography. It is also found that for negative resists, backscatter effects and resist contrast significantly degrade the resolution for large

  12. Simulation of the X-Ray Beam Absorption by the ABS-Plastic Filled with Different Metallic Additives

    NASA Astrophysics Data System (ADS)

    Miloichikova, I. A.; Stuchebrov, S. G.; Verigin, D. A.; Krasnykh, A. A.; Danilova, I. B.

    2016-11-01

    This article is a part of the work on developing new materials for manufacturing filaments for fused deposition modeling (FDM). The computations of depth dose distributions for gamma-radiation in ABS plastic filled with lead and zinc additives of various concentration were performed via Monte Carlo technique and are represented in graphic form.

  13. Far field beam pattern of one MW combined beam of laser diode array amplifiers for space power transmission

    NASA Technical Reports Server (NTRS)

    Kwon, Jin H.; Lee, Ja H.

    1989-01-01

    The far-field beam pattern and the power-collection efficiency are calculated for a multistage laser-diode-array amplifier consisting of about 200,000 5-W laser diode arrays with random distributions of phase and orientation errors and random diode failures. From the numerical calculation it is found that the far-field beam pattern is little affected by random failures of up to 20 percent of the laser diodes with reference of 80 percent receiving efficiency in the center spot. The random differences in phases among laser diodes due to probable manufacturing errors is allowed to about 0.2 times the wavelength. The maximum allowable orientation error is about 20 percent of the diffraction angle of a single laser diode aperture (about 1 cm). The preliminary results indicate that the amplifier could be used for space beam-power transmission with an efficiency of about 80 percent for a moderate-size (3-m-diameter) receiver placed at a distance of less than 50,000 km.

  14. Temporal evolution of the chemical structure during the pattern transfer by ion-beam sputtering

    NASA Astrophysics Data System (ADS)

    Ha, N.-B.; Jeong, S.; Yu, S.; Ihm, H.-I.; Kim, J.-S.

    2015-01-01

    Ru films patterned by ion-beam sputtering (IBS) serve as sacrificial masks for the transfer of the patterns to Si(1 0 0) and metallic glass substrates by continued IBS. Under the same sputter condition, however, both bare substrates remain featureless. Chemical analyses of the individual nano structures simultaneously with the investigation of their morphological evolution reveal that the pattern transfer, despite its apparent success, suffers from premature degradation before the mask is fully removed by IBS. Moreover, the residue of the mask or Ru atoms stubbornly remains near the surface, resulting in unintended doping or alloying of both patterned substrates.

  15. Direct-Writing of Cu Nano-Patterns with an Electron Beam.

    PubMed

    Lai, Shih-En; Hong, Ying-Jhan; Chen, Yu-Ting; Kang, Yu-Ting; Chang, Pin; Yew, Tri-Rung

    2015-12-01

    We demonstrate direct electron beam writing of a nano-scale Cu pattern on a surface with a thin aqueous layer of CuSO4 solution. Electron beams are highly maneuverable down to nano-scales. Aqueous solutions facilitate a plentiful metal ion supply for practical industrial applications, which may require continued reliable writing of sophisticated patterns. A thin aqueous layer on a surface helps to confine the writing on the surface. For this demonstration, liquid sample holder (K-kit) for transmission electron microscope (TEM) was employed to form a sealed space in a TEM. The aqueous CuSO4 solution inside the sample holder was allowed to partially dry until a uniform thin layer was left on the surface. The electron beam thus reduced Cu ions in the solution to form the desired patterns. Furthermore, the influence of e-beam exposure time and CuSO4(aq) concentration on the Cu reduction was studied in this work. Two growth stages of Cu were shown in the plot of Cu thickness versus e-beam exposure time. The measured Cu reduction rate was found to be proportional to the CuSO4(aq) concentration.

  16. Metastability in pixelation patterns of coexisting fluid lipid bilayer phases imposed by e-beam patterned substrates.

    PubMed

    Ogunyankin, Maria O; Longo, Marjorie L

    2013-02-14

    We study the dynamic evolution of pixilation patterns of the liquid-ordered (Lo) phase in coexistence with the liquid-disordered phase in lipid multibilayers. The pixilation patterns were formed by imposing lattice patterns of localized high curvature on phase-separating multibilayers using curvature-patterned regions of an underlying support. The projected radius of underlying hemisphere-like features, that provided the local curvature, was varied from 60 nm to 100 nm and the square lattice spacing between the features was varied between 200 nm and 400 nm using standard electron (e) -beam lithography. Over time, the area fraction of the Lo phase on the patterned regions of the substrate decreased toward zero at room temperature. This apparent metastability of the pattern derives from the high line energy of a pixelation pattern where a Boltzmann distribution shows near zero equilibrium partitioning of the Lo phase in the patterned regions. Kinetic rate analysis identifies two pattern-dependent mechanisms that dominate the transition to zero Lo area fraction; diffusion limited dissolution of the Lo phase driven by an Ostwald ripening-type process or the cooperative formation of vesicles containing Lo phase lipids. Interestingly, we observed the spontaneous formation of tubules in the corners of the array due to the high local curvature applied to the membrane. Furthermore we show that it is possible to regenerate pixilation patterns on the curvature-patterned regions by cooling below room temperature. Regenerated area fractions are in agreement with a room-temperature composition of primarily Ld phase and the high degree of overlap with the original patterns is suggestive of fixed nucleation sites.

  17. Analysis of surface plasmon interference pattern formed by optical vortex beams.

    PubMed

    Tan, P S; Yuan, X-C; Lin, J; Wang, Q; Burge, R E

    2008-10-27

    Following our recent experimental approach to excitation of surface plasmon polaritons induced by optical vortex beams [5], we report further analysis and verification of the surface plasmon interference pattern formed by locally excited standing surface plasmon polaritons in a metal/dielectric film. Our simulation model can be demonstrated by using angular spectrum representation. The generated standing interference pattern has potential as a resolution enhancement technique for sub-diffraction imaging.

  18. Test beam studies of the TRD prototype filled with different gas mixtures based on Xe, Kr, and Ar

    NASA Astrophysics Data System (ADS)

    Celebi, E.; Brooks, T.; Joos, M.; Rembser, C.; Gurbuz, S.; Cetin, S. A.; Konovalov, S. P.; Tikhomirov, V. O.; Zhukov, K.; Fillipov, K. A.; Romaniouk, A.; Smirnov, S. Yu; Teterin, P. E.; Vorobev, K. A.; Boldyrev, A. S.; Maevsky, A.; Derendarz, D.

    2017-01-01

    Towards the end of LHC Run1, gas leaks were observed in some parts of the Transition Radiation Tracker (TRT) of ATLAS. Due to these leaks, primary Xenon based gas mixture was replaced with Argon based mixture in various parts. Test-beam studies with a dedicated Transition Radiation Detector (TRD) prototype were carried out in 2015 in order to understand transition radiation performance with mixtures based on Argon and Krypton. We present and discuss the results of these test-beam studies with different active gas compositions.

  19. Direct laser patterning of self-assembled monolayer using elliptical laser beams: A theoretical parametric study

    NASA Astrophysics Data System (ADS)

    Zhang, Martin Y.; Shadnam, Mohammad Reza; Amirfazli, A.

    2011-11-01

    A theoretical quantitative analysis of processing parameters for application of an elliptical laser beam to achieve maximum patterning area is the focus of this study. Direct laser patterning (DLP) of self-assembled monolayers (SAM) is achieved by localized heating of the sample above the SAM desorption temperature. Through use of elliptical laser beams in the present work, three goals are achieved by analyzing the heat diffusion model and related thermo-kinetics model: (1) optimal working conditions (combination of laser power, scanning velocity and aspect ratio) for DLP to produce maximum feature size, or highest processing velocity at a given power; (2) identification of conditions that reduces the potential thermal damage to the substrate; (3) shedding light on issues related to uniformity or homogeneity of heating a substrate using an elliptical laser beam. A heat diffusion model is employed to provide the resulting surface temperature caused by elliptical laser beams, and the coupled thermo-kinetics model is used to determine the final SAM coverage generated by DLP. Parametric analysis revealed that 70-150 mW can be used to pattern feature sizes in the range of 2-10 times of equivalent circular beam size. It is also found that each elliptical laser beam has a unique optimal aspect ratio to result in the widest feature size for a given laser power and scanning velocity. The edge transition width increases with an increase of the aspect ratio. Keeping the aspect ratio of elliptical laser beam small (i.e. β<20), a sharp edge definition could be obtained; if an aspect ratio larger than 30 is used, a surface with gradual edge definition could be obtained.

  20. Single-Slit Diffraction Pattern of a Thermal Atomic Potassium Beam

    ERIC Educational Resources Information Center

    Leavitt, John A.; Bills, Francis A.

    1969-01-01

    The diffraction of a full thermal atomic potassium beam by a single slit was observed. Four experimental diffraction patterns were compared with that predicted by de Brogtie's hypothesis and simple scalar Fresnel diffraction theory. Possible reasons for the differences were discussed. (LC)

  1. Noncoplanar beam angle optimization in IMRT treatment planning using pattern search methods

    NASA Astrophysics Data System (ADS)

    Rocha, Humberto; Dias, Joana M.; Ferreira, Brígida C.; Lopes, Maria C.

    2015-05-01

    Radiation therapy is used to treat localized cancers, aiming to deliver a dose of radiation to the tumor volume to sterilize all cancer cells while minimizing the collateral effects on the surrounding healthy organs and tissues. The planning of radiation therapy treatments requires decisions regarding the angles used for radiation incidence, the fluence intensities and, if multileaf collimators are used, the definition of the leaf sequencing. The beam angle optimization problem consists in finding the optimal number and incidence directions of the irradiation beams. The selection of appropriate radiation incidence directions is important for the quality of the treatment. However, the possibility of improving the quality of treatment plans by an optimized selection of the beam incidences is seldom done in the clinical practice. Adding the possibility for noncoplanar incidences is even more rarely used. Nevertheless, the advantage of noncoplanar beams is well known. The optimization of noncoplanar beam incidences may further allow the reduction of the number of beams needed to reach a clinically acceptable plan. In this paper we present the benefits of using pattern search methods for the optimization of the highly non-convex noncoplanar beam angle optimization problem.

  2. Oxide degradation effects in dry patterning of resist using neutral oxygen beams

    SciTech Connect

    Mlynko, W.E.; Kasi, S.R.; Manos, D.

    1992-07-01

    Novel processing methods are being studied to address the highly selective and directional etch requirements of the ULSI manufacturing era; neutral molecular and atomic beams are two promising candidates. In this study, the potential of 5 eV neutral atomic oxygen beams for dry development of photoresist is demonstrated for application in patterning of CMOS devices. The patterning of photoresist directly on polysilicon gate layers enables the use of a self-contained dry processing strategy, with oxygen beams for resist etching and chlorine beams for polysilicon etching. Exposure to such reactive low-energy species and to the UV radiation from the line-of-sight, high-density plasma source can, however, after MOSFET gate oxide quality, impacting device performance and reliability. We have studied this processing related device integrity issue by subjecting polysilicon gas MOS structures to exposure treatments similar to those used in resist patterning using low energy oxygen beams. Electrical C-V characterization shows a significant increase in the oxide trapped charge and interface state density upon low energy exposure. I-V and dielectric breakdown characterization show increased low-field leakage characteristics for the same exposure. High-field electron injection studies reveal that the 0.25-V to 0.5-V negative flatband shifts can be partially annealed by the carrier injection. This could be due to positive charge annihilation or electron trapping, or some combination of both. Physical and analysis of patterned resist layers and electrical characterization data of MOS structures exposed to different neutral beam processing environments and following thermal annealing treatments is presented.

  3. Oxide degradation effects in dry patterning of resist using neutral oxygen beams

    SciTech Connect

    Mlynko, W.E.; Kasi, S.R. ); Manos, D. . Plasma Physics Lab.)

    1992-01-01

    Novel processing methods are being studied to address the highly selective and directional etch requirements of the ULSI manufacturing era; neutral molecular and atomic beams are two promising candidates. In this study, the potential of 5 eV neutral atomic oxygen beams for dry development of photoresist is demonstrated for application in patterning of CMOS devices. The patterning of photoresist directly on polysilicon gate layers enables the use of a self-contained dry processing strategy, with oxygen beams for resist etching and chlorine beams for polysilicon etching. Exposure to such reactive low-energy species and to the UV radiation from the line-of-sight, high-density plasma source can, however, after MOSFET gate oxide quality, impacting device performance and reliability. We have studied this processing related device integrity issue by subjecting polysilicon gas MOS structures to exposure treatments similar to those used in resist patterning using low energy oxygen beams. Electrical C-V characterization shows a significant increase in the oxide trapped charge and interface state density upon low energy exposure. I-V and dielectric breakdown characterization show increased low-field leakage characteristics for the same exposure. High-field electron injection studies reveal that the 0.25-V to 0.5-V negative flatband shifts can be partially annealed by the carrier injection. This could be due to positive charge annihilation or electron trapping, or some combination of both. Physical and analysis of patterned resist layers and electrical characterization data of MOS structures exposed to different neutral beam processing environments and following thermal annealing treatments is presented.

  4. Filling gaps in large ecological databases: consequences for the study of global-scale plant functional trait patterns

    NASA Astrophysics Data System (ADS)

    Schrodt, Franziska; Shan, Hanhuai; Fazayeli, Farideh; Karpatne, Anuj; Kattge, Jens; Banerjee, Arindam; Reichstein, Markus; Reich, Peter

    2013-04-01

    With the advent of remotely sensed data and coordinated efforts to create global databases, the ecological community has progressively become more data-intensive. However, in contrast to other disciplines, statistical ways of handling these large data sets, especially the gaps which are inherent to them, are lacking. Widely used theoretical approaches, for example model averaging based on Akaike's information criterion (AIC), are sensitive to missing values. Yet, the most common way of handling sparse matrices - the deletion of cases with missing data (complete case analysis) - is known to severely reduce statistical power as well as inducing biased parameter estimates. In order to address these issues, we present novel approaches to gap filling in large ecological data sets using matrix factorization techniques. Factorization based matrix completion was developed in a recommender system context and has since been widely used to impute missing data in fields outside the ecological community. Here, we evaluate the effectiveness of probabilistic matrix factorization techniques for imputing missing data in ecological matrices using two imputation techniques. Hierarchical Probabilistic Matrix Factorization (HPMF) effectively incorporates hierarchical phylogenetic information (phylogenetic group, family, genus, species and individual plant) into the trait imputation. Advanced Hierarchical Probabilistic Matrix Factorization (aHPMF) on the other hand includes climate and soil information into the matrix factorization by regressing the environmental variables against residuals of the HPMF. One unique opportunity opened up by aHPMF is out-of-sample prediction, where traits can be predicted for specific species at locations different to those sampled in the past. This has potentially far-reaching consequences for the study of global-scale plant functional trait patterns. We test the accuracy and effectiveness of HPMF and aHPMF in filling sparse matrices, using the TRY

  5. Localized conductive patterning via focused electron beam reduction of graphene oxide

    SciTech Connect

    Kim, Songkil; Henry, Mathias; Kulkarni, Dhaval D.; Zackowski, Paul; Jang, Seung Soon; Tsukruk, Vladimir V.; Fedorov, Andrei G.

    2015-03-30

    We report on a method for “direct-write” conductive patterning via reduction of graphene oxide (GO) sheets using focused electron beam induced deposition (FEBID) of carbon. FEBID treatment of the intrinsically dielectric graphene oxide between two metal terminals opens up the conduction channel, thus enabling a unique capability for nanoscale conductive domain patterning in GO. An increase in FEBID electron dose results in a significant increase of the domain electrical conductivity with improving linearity of drain-source current vs. voltage dependence, indicative of a change of graphene oxide electronic properties from insulating to semiconducting. Density functional theory calculations suggest a possible mechanism underlying this experimentally observed phenomenon, as localized reduction of graphene oxide layers via interactions with highly reactive intermediates of electron-beam-assisted dissociation of surface-adsorbed hydrocarbon molecules. These findings establish an unusual route for using FEBID as nanoscale lithography and patterning technique for engineering carbon-based nanomaterials and devices with locally tailored electronic properties.

  6. Rheological properties of styrene-butadiene rubber filled with electron beam modified surface treated dual phase fillers

    NASA Astrophysics Data System (ADS)

    Shanmugharaj, A. M.; Bhowmick, Anil K.

    2004-01-01

    The rheological properties of styrene-butadiene rubber (SBR) loaded with dual phase filler were measured using Monsanto Processability Tester (MPT) at three different temperatures (100°C, 110°C and 130°C) and four different shear rates (61.3, 306.3, 613, and 1004.5 s -1). The effect of electron beam modification of dual phase filler in absence and presence of trimethylol propane triacrylate (TMPTA) or triethoxysilylpropyltetrasulphide (Si-69) on melt flow properties of SBR was also studied. The viscosity of all the systems decreases with shear rate indicating their pseudoplastic or shear thinning nature. The higher shear viscosity for the SBR loaded with the electron beam modified filler is explained in terms of variation in structure of the filler upon electron beam irradiation. Die swell of the modified filler loaded SBR is slightly higher than that of the unmodified filler loaded rubber, which is explained by calculating normal stress difference for the systems. Activation energy of the modified filler loaded SBR systems is also slightly higher than that of the control filler loaded SBR system.

  7. Electron-beam-induced ferroelectric domain behavior in the transmission electron microscope: Toward deterministic domain patterning

    NASA Astrophysics Data System (ADS)

    Hart, James L.; Liu, Shi; Lang, Andrew C.; Hubert, Alexander; Zukauskas, Andrius; Canalias, Carlota; Beanland, Richard; Rappe, Andrew M.; Arredondo, Miryam; Taheri, Mitra L.

    2016-11-01

    We report on transmission electron microscope beam-induced ferroelectric domain nucleation and motion. While previous observations of this phenomenon have been reported, a consistent theory explaining induced domain response is lacking, and little control over domain behavior has been demonstrated. We identify positive sample charging, a result of Auger and secondary electron emission, as the underlying mechanism driving domain behavior. By converging the electron beam to a focused probe, we demonstrate controlled nucleation of nanoscale domains. Molecular dynamics simulations performed are consistent with experimental results, confirming positive sample charging and reproducing the result of controlled domain nucleation. Furthermore, we discuss the effects of sample geometry and electron irradiation conditions on induced domain response. These findings elucidate past reports of electron beam-induced domain behavior in the transmission electron microscope and provide a path towards more predictive, deterministic domain patterning through electron irradiation.

  8. Observation of speckle pattern and interference fringe forks in stimulated Raman scattering beam profile

    NASA Astrophysics Data System (ADS)

    Drampyan, Raphael K.

    2001-05-01

    The circularly distributed speckle pattern, as well as interference fringe structure in profile of the beam of stimulated Raman scattering (SRS) I Stokes component, pumped by multimode radiation with nearly four-fold azimuthal symmetry, have been observed. The SRS was excited near the threshold of generation by nanosecond pulses of laser radiation at wavelength 530 nm. The profile of output pump beam had a uniform intensity distribution, whereas the SRS beam profile showed kaleidoscopic change from shot to shot, while the energies of input pulses were kept stable. The interference fringes showed a number of points where the fringes originated or vanished. Such behavior, which is the vortex signature, allows to suppose that SRS waves, generated from quantum noise, carry screw dislocations.

  9. E-beam patterning and stability study of sub-22nm HSQ pillars

    NASA Astrophysics Data System (ADS)

    Chen, Wei-Su; Tsai, Ming-Jinn

    2011-04-01

    E-beam exposed HSQ resist pillar (island) is commonly used as the hard mask for dry etching. However, HSQ pillar is prone to collapse without any substrate pre-treatment. CD resolution of HSQ pattern also depends on the aging effect. In this work, factors of (1) designed CD (DCD) (2) dose vs L/S ratio (3) beam current (4) underlayer (UL) (5) post-coat-delay (PCD) time before e-beam writing are studied for forming stable and reproducible sub-22 nm HSQ pillar. Three kinds of underlayer are evaluated, i.e. AR3-600, ZEP520A and TDUR-N700. Experimental results are summarized below. A wider dose window of forming sub-22 nm HSQ pillar with looser L/S ratio or smaller designed CD is obtained. CD variation for all pattern density conditions is due to the proximity effect from beam blur. AR3-600 is shown to be the most suitable UL for HSQ pillar. CD of HSQ pillar increases with thicker AR3-600 layer. PCD range for stable CDs of HSQ pillar with DCD of 20 nm is larger than that with 15 nm.

  10. Echolocation signals and transmission beam pattern of a false killer whale (Pseudorca crassidens).

    PubMed

    Au, W W; Pawloski, J L; Nachtigall, P E; Blonz, M; Gisner, R C

    1995-07-01

    The echolocation transmission beam pattern of a false killer whale (Pseudorca crassidens) was measured in the vertical and horizontal planes. A vertical array of seven broadband miniature hydrophones was used to measure the beam pattern in the vertical plane and a horizontal array of the same hydrophones was used in the horizontal plane. The measurements were performed in the open waters of Kaneohe Bay, Oahu, Hawaii, while the whale performed a target discrimination task. Four types of signals, characterized by their frequency spectra, were measured. Type-1 signals had a single low-frequency peak at 40 +/- 9 kHz and a low-amplitude shoulder at high frequencies. Type-2 signals had a bimodal frequency characteristic with a primary peak at 46 +/- 7 kHz and a secondary peak at 88 +/- 13 kHz. Type-3 signals were also bimodal but with a primary peak at 100 +/- 7 kHz and a secondary peak at 49 +/- 9 kHz. Type-4 signals had a single high-frequency peak at 104 +/- 7 kHz. The center frequency of the signals were found to be linearly correlated to the peak-to-peak source level, increasing with increasing source level. The major axis of the vertical beam was directed slightly downward between 0 and -5 degrees, in contrast to the +5 to 10 degrees for Tursiops and Delphinapterus. The beam in the horizontal plane was directed forward between 0 degrees and -5 degrees.(ABSTRACT TRUNCATED AT 250 WORDS)

  11. Proof of concept demonstration for coherent beam pattern measurements of KID detectors

    NASA Astrophysics Data System (ADS)

    Davis, Kristina K.; Baryshev, Andrey M.; Jellema, Willem; Yates, Stephen J. C.; Ferrari, Lorenza; Baselmans, Jochem J. A.

    2016-07-01

    Here we summarize the initial results from a complex field radiation pattern measurement of a kinetic inductance detector instrument. These detectors are phase insensitive and have thus been limited to scalar, or amplitude-only, beam measurements. Vector beam scans, of both amplitude and phase, double the information received in comparison to scalar beam scans. Scalar beam measurements require multiple scans at varying distances along the optical path of the receiver to fully constrain the divergence angle of the optical system and locate the primary focus. Vector scans provide this information with a single scan, reducing the total measurement time required for new systems and also limiting the influence of system instabilities. The vector scan can be taken at any point along the optical axis of the system including the near-field, which makes beam measurements possible for large systems at high frequencies where these measurements may be inconceivable to be tested in-situ. Therefore, the methodology presented here should enable common heterodyne analysis for direct detector instruments. In principle, this coherent measurement strategy allows phase dependent analysis to be performed on any direct-detect receiver instrument.

  12. Understanding the emission pattern produced by focused laser beam excitation of perylene square single crystals

    NASA Astrophysics Data System (ADS)

    Takazawa, Ken

    2017-01-01

    Square single crystals of perylene (α-crystals) exhibit a peculiar emission pattern when excited by a focused laser beam. Fluorescence spots are observed at the point of excitation and at four edges, with the lines connecting the excitation point and edge emissions being perpendicular to the edges irrespective of the excitation position. Two different mechanisms explaining this emission pattern have been proposed so far. Our newly designed experiment and analysis revealed that the involved mechanism features a combination of the waveguide effect and total internal reflection by crystal edges.

  13. Optimization of Neural Network Pattern Recognition Systems for Guided Waves Damage Identification in Beams

    NASA Astrophysics Data System (ADS)

    Liew, C. K.; Veidt, M.

    2007-03-01

    Neural network pattern recognition is an advanced regression technique that can be applied to identify guided wave response signals for quantifying damages in structures. This paper describes a procedure to optimize the design of a multi-layer perceptron backpropagation neural network with signals preprocessed by the wavelet transform. The performance can be further improved using a weight-range selection technique in a series network since there is increased sensitivity of the neural network to experimental damage patterns if the training range is reduced. Damage identification in beams with longitudinal guided waves is used in this study.

  14. Reflective electron beam lithography: lithography results using CMOS controlled digital pattern generator chip

    NASA Astrophysics Data System (ADS)

    Gubiotti, Thomas; Sun, Jeff Fuge; Freed, Regina; Kidwingira, Francoise; Yang, Jason; Bevis, Chris; Carroll, Allen; Brodie, Alan; Tong, William M.; Lin, Shy-Jay; Wang, Wen-Chuan; Haspeslagh, Luc; Vereecke, Bart

    2013-03-01

    Maskless electron beam lithography can potentially extend semiconductor manufacturing to the 10 nm logic (16 nm half pitch) technology node and beyond. KLA-Tencor is developing Reflective Electron Beam Lithography (REBL) technology targeting high-volume 10 nm logic node performance. REBL uses a novel multi-column wafer writing system combined with an advanced stage architecture to enable the throughput and resolution required for a NGL system. Using a CMOS Digital Pattern Generator (DPG) chip with over one million microlenses, the system is capable of maskless printing of arbitrary patterns with pixel redundancy and pixel-by-pixel grayscaling at the wafer. Electrons are generated in a flood beam via a thermionic cathode at 50-100 keV and decelerated to illuminate the DPG chip. The DPG-modulated electron beam is then reaccelerated and demagnified 80-100x onto the wafer to be printed. Previously, KLA-Tencor reported on the development progress of the REBL tool for maskless lithography at and below the 10 nm logic technology node. Since that time, the REBL team has made good progress towards developing the REBL system and DPG for direct write lithography. REBL has been successful in manufacturing a CMOS controlled DPG chip with a stable charge drain coating and with all segments functioning. This DPG chip consists of an array of over one million electrostatic lenslets that can be switched on or off via CMOS voltages to pattern the flood electron beam. Testing has proven the validity of the design with regards to lenslet performance, contrast, lifetime, and pattern scrolling. This chip has been used in the REBL demonstration platform system for lithography on a moving stage in both PMMA and chemically amplified resist. Direct imaging of the aerial image has also been performed by magnifying the pattern at the wafer plane via a mag stack onto a YAG imaging screen. This paper will discuss the chip design improvements and new charge drain coating that have resulted in a

  15. Direct patterning of self-assembled monolayers on gold using a laser beam.

    PubMed

    Shadnam, Mohammad R; Kirkwood, Sean E; Fedosejevs, Robert; Amirfazli, A

    2004-03-30

    The development of a methodology to manipulate surface properties of a self-assembled monolayer (SAM) of alkanethiol on a gold film using direct laser patterning is the objective of this paper. The present study demonstrates proof of the concept for the feasibility of laser patterning monolayers and outlines theoretical modeling of the process to predict the resulting feature size. This approach is unique in that it eliminates the need for photolithography, is noncontact, and can be extended to other systems such as SAMs on silicon wafers or potentially polymeric substrates. A homogeneous SAM made of 1-hexadecanethiol is formed on a 300-A sputtered film of gold (supported by a soda lime glass substrate). Localized regions are then desorbed by scanning the focal spot of a 488-nm continuous-wave argon ion laser beam under a nitrogen atmosphere. The desorption occurs as a result of a high substrate temperature produced by the moving laser beam with a Gaussian spatial profile at a constant speed of 200 microm/s. After completing the scans, the sample is dipped into a dilute solution of 16-mercaptohexadecanoic acid and a hydrophilic monolayer self-assembles along the previously irradiated regions. The resultant lines are viewed, and line widths are measured using both wetting with tridecane under a light microscope and scanning electron microscopy. Using the direct laser patterning method, we have produced straight line patterns with widths of 28-170 microm. A thermal model was constructed to predict the line width of the desorbed monolayer. The effect of the laser power, beam waist, and temperature dependence of the substrate conductivity on the theoretical predictions is considered. It is shown that the theoretical predictions are in good agreement with the experimental results, and, thus, the model can effectively be used to predict experimental results.

  16. Beam angle optimization for intensity-modulated radiation therapy using a guided pattern search method

    NASA Astrophysics Data System (ADS)

    Rocha, Humberto; Dias, Joana M.; Ferreira, Brígida C.; Lopes, Maria C.

    2013-05-01

    Generally, the inverse planning of radiation therapy consists mainly of the fluence optimization. The beam angle optimization (BAO) in intensity-modulated radiation therapy (IMRT) consists of selecting appropriate radiation incidence directions and may influence the quality of the IMRT plans, both to enhance better organ sparing and to improve tumor coverage. However, in clinical practice, most of the time, beam directions continue to be manually selected by the treatment planner without objective and rigorous criteria. The goal of this paper is to introduce a novel approach that uses beam’s-eye-view dose ray tracing metrics within a pattern search method framework in the optimization of the highly non-convex BAO problem. Pattern search methods are derivative-free optimization methods that require a few function evaluations to progress and converge and have the ability to better avoid local entrapment. The pattern search method framework is composed of a search step and a poll step at each iteration. The poll step performs a local search in a mesh neighborhood and ensures the convergence to a local minimizer or stationary point. The search step provides the flexibility for a global search since it allows searches away from the neighborhood of the current iterate. Beam’s-eye-view dose metrics assign a score to each radiation beam direction and can be used within the pattern search framework furnishing a priori knowledge of the problem so that directions with larger dosimetric scores are tested first. A set of clinical cases of head-and-neck tumors treated at the Portuguese Institute of Oncology of Coimbra is used to discuss the potential of this approach in the optimization of the BAO problem.

  17. Effective beam pattern of the Blainville's beaked whale (Mesoplodon densirostris) and implications for passive acoustic monitoring.

    PubMed

    Shaffer, Jessica Ward; Moretti, David; Jarvis, Susan; Tyack, Peter; Johnson, Mark

    2013-03-01

    The presence of beaked whales in mass-strandings coincident with navy maneuvers has prompted the development of methods to detect these cryptic animals. Blainville's beaked whales, Mesoplodon densirostris, produce distinctive echolocation clicks during long foraging dives making passive acoustic detection a possibility. However, performance of passive acoustic monitoring depends upon the source level, beam pattern, and clicking behavior of the whales. In this study, clicks recorded from Digital acoustic Tags (DTags) attached to four M. densirostris were linked to simultaneous recordings from an 82-hydrophone bottom-mounted array to derive the source level and beam pattern of the clicks, as steps towards estimating their detectability. The mean estimated on-axis apparent source level for the four whales was 201 dBrms97. The mean 3 dB beamwidth and directivity index, estimated from sequences of clicks directed towards the far-field hydrophones, were 13° and 23 dB, respectively. While searching for prey, Blainville's beaked whales scan their heads horizontally at a mean rate of 3.6°/s over an angular range of some +/-10°. Thus, while the DI indicates a narrow beam, the area of ensonification over a complete foraging dive is large given the combined effects of body and head movements associated with foraging.

  18. Hall Thruster Plume Studies using the BeamServer Antenna Pattern Code

    NASA Astrophysics Data System (ADS)

    Hallock, G. A.; Wiley, J. C.; Garcia, A.; Zuniga, C.; Boulgakov, A.; Meyer, J. W.; Loane, J. T.

    2002-11-01

    BeamServer is a ray tracing code developed to study the effect of plasma thruster plumes on satellite communication signals. Rays are launched from the antenna feed, traced through the region containing antenna reflectors and plasma, and terminated on an exit surface. The electric field on the exit surface is then used to calculate the far-field antenna pattern, using the radiation integral. To verify both the code operation and our thruster plasma density models a "ground test" is planned, where a Hall thruster will be operated in a vacuum tank and a microwave system will transmit through the plume. Direct comparisons with ground test experimental data can be made on the BeamServer exit plane. To facilitate this extensive studies of the electric field magnitude and phase as a function of frequency and spatial location have been made. In addition, the Hall thruster exhibits large amplitude plasma instabilities, typically in the 25 KHz range. We have added instability models to the BeamServer code, and added time as a variable. Fourier transforms can be applied to either the exit plane or far-field patterns. We will present these studies and discuss the planned ground test.

  19. Three-dimensional beam pattern of regular sperm whale clicks confirms bent-horn hypothesis

    NASA Astrophysics Data System (ADS)

    Zimmer, Walter M. X.; Tyack, Peter L.; Johnson, Mark P.; Madsen, Peter T.

    2005-03-01

    The three-dimensional beam pattern of a sperm whale (Physeter macrocephalus) tagged in the Ligurian Sea was derived using data on regular clicks from the tag and from hydrophones towed behind a ship circling the tagged whale. The tag defined the orientation of the whale, while sightings and beamformer data were used to locate the whale with respect to the ship. The existence of a narrow, forward-directed P1 beam with source levels exceeding 210 dBpeak re: 1 μPa at 1 m is confirmed. A modeled forward-beam pattern, that matches clicks >20° off-axis, predicts a directivity index of 26.7 dB and source levels of up to 229 dBpeak re: 1 μPa at 1 m. A broader backward-directed beam is produced by the P0 pulse with source levels near 200 dBpeak re: 1 μPa at 1 m and a directivity index of 7.4 dB. A low-frequency component with source levels near 190 dBpeak re: 1 μPa at 1 m is generated at the onset of the P0 pulse by air resonance. The results support the bent-horn model of sound production in sperm whales. While the sperm whale nose appears primarily adapted to produce an intense forward-directed sonar signal, less-directional click components convey information to conspecifics, and give rise to echoes from the seafloor and the surface, which may be useful for orientation during dives..

  20. EUV mask pattern inspection with an advanced electron beam inspection system

    NASA Astrophysics Data System (ADS)

    Shimomura, Takeya; Inazuki, Yuichi; Tsukasa, Abe; Takikawa, Tadahiko; Morikawa, Yasutaka; Mohri, Hiroshi; Hayashi, Naoya; Wang, Fei; Ma, Long; Zhao, Yan; Kuan, Chiyan; Xiao, Hong; Jau, Jack

    2009-12-01

    Readiness of defect-free mask is one of the biggest challenges to insert extreme ultraviolet (EUV) lithography into semiconductor high volume manufacturing for 22nm half pitch (HP) node and beyond. According to ITRS roadmap updated in 2008, minimum size of defect needed to be removed is 25nm for 22nm HP node in 2013 [1]. It is necessary, therefore, to develop EUV mask pattern inspection tool being capable of detecting 25nm defect. Electron beam inspection (EBI) is one of promising tools which will be able to meet such a tight defect requirement. In this paper, we evaluated defect detection sensitivity of electron beam inspection (EBI) system developed by Hermes Microvision, Inc. (HMI) using 88nm half-pitch (HP) line-and-space (L/S) pattern and 128nm HP contact-hole (C/H) pattern EUV mask. We found the EBI system can detect 25nm defects. We, furthermore, fabricated 4 types of EUV mask structures: 1) w/ anti-reflective (AR) layer and w/ buffer layer, 2) w/ AR layer and w/o buffer layer, 3) w/o AR layer and w/ buffer layer, 4) w/o AR layer and w/o buffer layer. And the sensitivity and inspectability for the EBI were compared. It was observed that w/o AR layer structure introduce higher image contrast and lead to better inspectability, although there is no significant different in sensitivity.

  1. Patterning of Aluminium thin film on polyethylene terephthalate by multi-beam picosecond laser

    NASA Astrophysics Data System (ADS)

    Jin, Y.; Perrie, W.; Harris, P.; Allegre, O. J.; Abrams, K. J.; Dearden, G.

    2015-11-01

    High speed patterning of a 30 nm thick Aluminium thin film on a flexible Polyethylene Terephthalate substrate was demonstrated with the aid of Computer Generated Holograms (CGH's) applied to a phase only Spatial Light Modulator. Low fluence picosecond laser pulses minimise thermal damage to the sensitive substrate and thus clean, single and multi-beam, front side thin film removal is achieved with good edge quality. Interestingly, rear side ablation shows significant Al film delamination. Measured front and rear side ablation thresholds were Fth=0.20±0.01 J cm-2 and Fth=0.15±0.01 J cm-2 respectively. With laser repetition rate of 200 kHz and 8 diffractive spots, a film removal rate of R>0.5 cm2 s-1 was demonstrated during patterning with a fixed CGH and 5 W average laser power. The effective laser repetition rate was feff~1.3 MHz. The application of 30 stored CGH's switching up to 10 Hz was also synchronised with motion control, allowing dynamic large area multi-beam patterning which however, slows micro-fabrication.

  2. Enhanced e-beam pattern writing for nano-optics based on character projection

    NASA Astrophysics Data System (ADS)

    Kley, E.-Bernhard; Schmidt, Holger; Zeitner, Uwe; Banasch, Michael; Schnabel, Bernd

    2012-02-01

    The pattern generation for nano-optics raises high demands on resolution, writing speed and flexibility: nearly arbitrary complex structures with feature sizes below 100 nm should be realized on large areas up to 9 inches in square within reasonable time. With e-beam lithography the requirements on resolution and flexibility can be fulfilled but the writing time becomes the bottle neck. Acceleration by Variable Shaped Beam (VSB) writing principle (geometrical primitives with flexible size can be exposed with a single shot) is sometimes not sufficient. Character Projection (CP) is able to speed up the writing drastically because complex pattern of a limited area can be exposed by one shot [1]. We tested CP in the Vistec SB350 OS for optical applications and found a shot count reduction up to 1/1000, especially for geometries which are hard to approximate by geometrical primitives. Additionally, the resolution and the pattern quality were influenced in a positive way. Another benefit is the possibility to spend a part of the gain in writing speed to the use of a high resolution but low sensitive resist like HSQ. The tradeoff between speed and flexibility should be compensable by a large number of characters available.

  3. A Study on Peripheral Visibility under Different Headlamp Low-beam Pattern

    NASA Astrophysics Data System (ADS)

    Chen, Wencheng; Lin, Yandan; Kojima, Shinichi; Chen, Dahua

    In this article peripheral visibility under the condition of three types of headlamps' low-beam pattern was compared with the Two-Alternative Forced-Choice (2AFC) method. The three headlamps used in this night-time field study were headlamp No.1: Parabolic-HID, Headlamp No.2: Projector-HID and Headlamp No.3: Parabolic-Halogen. The results show that HID headlamps are better for the detection of pedestrian in peripheral than halogen headlamps because of the higher light output, higher color temperature, brighter foreground and wider spread of light. Some suggestion about criteria of the automobile headlight distribution for Chinese traffic condition was also discussed.

  4. Mitigating illumination gradients in a SAR image based on the image data and antenna beam pattern

    SciTech Connect

    Doerry, Armin W.

    2013-04-30

    Illumination gradients in a synthetic aperture radar (SAR) image of a target can be mitigated by determining a correction for pixel values associated with the SAR image. This correction is determined based on information indicative of a beam pattern used by a SAR antenna apparatus to illuminate the target, and also based on the pixel values associated with the SAR image. The correction is applied to the pixel values associated with the SAR image to produce corrected pixel values that define a corrected SAR image.

  5. Effects of polycrystallinity in nano patterning by ion-beam sputtering

    SciTech Connect

    Yoon, Sun Mi; Kim, J.-S.; Yoon, D.; Cheong, H.; Kim, Y.; Lee, H. H.

    2014-07-14

    Employing graphites with distinctly different mean grain sizes, we study the effects of polycrystallinity on the pattern formation by ion-beam sputtering. The grains influence the growth of the ripples in a highly anisotropic fashion; both the mean uninterrupted ripple length along the ridges and the surface width depend on the mean size of the grains, which is attributed to the large sputter yield at the grain boundary compared with that on the terrace. In contrast, the ripple wavelength does not depend on the mean size of the grains, indicating that the mass transport across the grain boundaries should efficiently proceed by both thermal diffusion and ion-induced processes.

  6. Domain patterning by electron beam of MgO doped lithium niobate covered by resist

    SciTech Connect

    Shur, V. Ya. Chezganov, D. S.; Akhmatkhanov, A. R.; Kuznetsov, D. K.

    2015-06-08

    Periodical domain structuring by focused electron beam irradiation of MgO-doped lithium niobate (MgOCLN) single crystalline plate covered by resist layer was studied both experimentally and by computer simulation. The dependences of domain size on the charge dose and distance between isolated domains were measured. It has been shown that the quality of periodical domain pattern depends on the thickness of resist layer and electron energy. The experimentally obtained periodic domain structures have been divided into four types. The irradiation parameters for the most uniform patterning were obtained experimentally. It was shown by computer simulation that the space charge slightly touching the crystal surface produced the maximum value of electric field at the resist/LN interface thus resulting in the best pattern quality. The obtained knowledge allowed us to optimize the poling process and to make the periodical domain patterns in 1-mm-thick wafers with an area up to 1 × 5 mm{sup 2} and a period of 6.89 μm for green light second harmonic generation. Spatial distribution of the efficiency of light frequency conversion confirmed the high homogeneity of the tailored domain patterns.

  7. Patterns of broad-beam antennas of different polarizations next to simple Hangar models

    NASA Technical Reports Server (NTRS)

    Cockrell, C. R.

    1977-01-01

    Broad-beam antennas of different polarizations radiating next to simple hangar models are investigated. Expressions that represent the elevation-plane patterns of slots in and 1/4 wavelength monopoles on a finite rectangular ground plane upon which a rectangular scattering object was placed were derived using geometrical theory of diffraction. These expressions were obtained by superposing the infinite ground plane solutions, reflected field solutions from the scattering object and diffracted field solutions in their respective regions of validity. Patterns for a 1/2 wavelength slot and 1/4 wavelength electric monopole are verified experimentally for a number of source locations. Data pertaining to the polarization question in regard to the multipath problem are presented.

  8. Extremum-seeking control of the beam pattern of a reconfigurable holographic metamaterial antenna.

    PubMed

    Johnson, Mikala C; Brunton, Steven L; Kundtz, Nathan B; Kutz, Nathan J

    2016-01-01

    Robust, continuous, and software-defined beam pattern control of holographic metamaterial antennas is necessary to realize the potential of these low-power-consumption, thin, lightweight, inexpensive antennas for consumer usage of satellite communication. We present a complete feedback control approach that enables adaptive control of the radiation pattern for the electronically scanned metamaterial antenna that is robust to measurement noise and is able to continuously optimize performance throughout changing environmental conditions and antenna characteristics. The physical size, weight, and cost advantages of the metamaterial antenna make it an attractive technology when paired with robust and adaptive on-board software strategies to optimize antenna performance and self-tune for various environmental conditions.

  9. Influence of metal co-deposition on silicon nanodot patterning dynamics during ion-beam sputtering

    NASA Astrophysics Data System (ADS)

    Gago, R.; Redondo-Cubero, A.; Palomares, F. J.; Vázquez, L.

    2014-10-01

    We address the impact of metal co-deposition in the nanodot patterning dynamics of Si(100) surfaces under normal-incidence 1 keV Ar+ ion-beam sputtering (IBS). In particular, the effect of both the metal nature (Fe or Mo) and flux has been studied. Morphological and compositional evolution were followed by atomic force microscopy (AFM) and Rutherford backscattering spectrometry, respectively. For the same type of impurity, the dynamics is faster for a higher co-deposition flux, which also drives to larger asymptotic roughness and wavelength. Mo co-deposition yields rougher surfaces for a lower metal coverage than Fe and, remarkably, higher ordered patterns. X-ray photoelectron spectroscopy reveals the formation of silicide bonds even before pattern onset, stressing the relevant role of the affinity of the co-deposited metals for silicon. Further, current-sensing AFM performed at the initial and asymptotic stages indicates that the nanodot structures are metal-rich, resulting in coupled compositional and morphological patterns. These results are discussed in terms of phase segregation, morphology-driven local flux variations of impurities and silicide formation. This analysis reveals that the underlying (concurrent) mechanisms of pattern formation are complex since many processes can come into play with a different relative weight depending on the specific patterning conditions. From a practical point of view, it is shown that, by proper selection of the process parameters, IBS with metal co-deposition can be used to tune the dynamics and pattern properties and, interestingly, to produce highly ordered arrays.

  10. Millimeter Wave MIMO Channel Estimation Using Overlapped Beam Patterns and Rate Adaptation

    NASA Astrophysics Data System (ADS)

    Kokshoorn, Matthew; Chen, He; Wang, Peng; Li, Yonghui; Vucetic, Branka

    2017-02-01

    This paper is concerned with the channel estimation problem in Millimeter wave (mmWave) wireless systems with large antenna arrays. By exploiting the inherent sparse nature of the mmWave channel, we first propose a fast channel estimation (FCE) algorithm based on a novel overlapped beam pattern design, which can increase the amount of information carried by each channel measurement and thus reduce the required channel estimation time compared to the existing non-overlapped designs. We develop a maximum likelihood (ML) estimator to optimally extract the path information from the channel measurements. Then, we propose a novel rate-adaptive channel estimation (RACE) algorithm, which can dynamically adjust the number of channel measurements based on the expected probability of estimation error (PEE). The performance of both proposed algorithms is analyzed. For the FCE algorithm, an approximate closed-form expression for the PEE is derived. For the RACE algorithm, a lower bound for the minimum signal energy-to-noise ratio required for a given number of channel measurements is developed based on the Shannon-Hartley theorem. Simulation results show that the FCE algorithm significantly reduces the number of channel estimation measurements compared to the existing algorithms using non-overlapped beam patterns. By adopting the RACE algorithm, we can achieve up to a 6dB gain in signal energy-to-noise ratio for the same PEE compared to the existing algorithms.

  11. Facile fabrication of nanogap electrodes for suspended graphene characterization using direct ion beam patterning

    NASA Astrophysics Data System (ADS)

    Qi, Zhengqing John; Johnson, A. T. Charlie

    2014-03-01

    Graphene is a two-dimensional sheet of carbon atoms with exceptional electronic and mechanical properties, giving it tremendous potential in nanoelectromechanical system devices. Here, we present a method to easily and reproducibly fabricate suspended graphene nanoribbons across nanogap electrodes of various separation lengths, demonstrating a technique with aggressive gap scalability and device geometry control. Fabrication is based on using a focused gallium ion beam to create a slit between joined electrodes prepatterened on a 100 nm thick silicon nitride membrane. The transparency of the nitride membrane provides reduced ion backscattering and adds milling resolution. Large-area monolayer graphene grown by atmospheric pressure chemical vapor deposition was transferred onto the silicon nitride chip and patterned into a free-standing ribbon geometry via electron beam lithography on organic ebeam resist followed by an O2 plasma etch. We find that commonly used inorganic negative tone resist that requires a buffered oxide etch for resist removal will attack the adhesion layer (Cr2O3) between the electrode and nitride membrane, which is exposed immediately after milling, so an organic resist was selected to avoid this. Using this technique, we fabricate freestanding graphene devices contacted by electrodes of sub-100 nm separation length and preform a comparative study on the effects of current annealing on device resistance. The gap resolution of this technique is limited by the gallium ion beam, which allows for sub-100 nm gaps. Sub-10 nm gaps are feasible with He ion beams, proving direct applications in probing the high field transport properties of graphene nanoribbons at post-CMOS length scales.

  12. Direct Write Protein Patterns for Multiplexed Cytokine Detection From Live Cells Using Electron Beam Lithography

    PubMed Central

    Lau, Uland Y.; Saxer, Sina S.; Lee, Juneyoung; Bat, Erhan; Maynard, Heather D.

    2016-01-01

    Simultaneous detection of multiple biomarkers, such as extracellular signaling molecules, is a critical aspect in disease profiling and diagnostics. Precise positioning of antibodies on surfaces, especially at the micro- and nano- scale, is important for the improvement of assays, biosensors, and diagnostics on the molecular level, and therefore, the pursuit of device miniaturization for parallel, fast, low-volume assays is a continuing challenge. Here, we describe a multiplexed cytokine immunoassay utilizing electron beam lithography and a trehalose glycopolymer as a resist for the direct writing of antibodies on silicon substrates allowing for micro- and nano-scale precision of protein immobilization. Specifically, anti-interleukin 6 (IL-6) and anti-tumor necrosis factor alpha (TNFα) antibodies were directly patterned. Retention of the specific binding properties of the patterned antibodies was shown by the capture of secreted cytokines from stimulated RAW 264.7 macrophages. A sandwich immunoassay was employed using gold nanoparticles and enhancement with silver for the detection and visualization of bound cytokines to the patterns by localized surface plasmon resonance detected with dark field microscopy. Multiplexing with both IL-6 and TNFα on a single chip was also successfully demonstrated with high specificity and in relevant cell culture conditions and at different times after cell stimulation. The direct fabrication of capture antibody patterns for cytokine detection described here could be useful for biosensing applications. PMID:26679368

  13. Amazonian mid- to high-latitude glaciation on Mars: Supply-limited ice sources, ice accumulation patterns, and concentric crater fill glacial flow and ice sequestration

    NASA Astrophysics Data System (ADS)

    Fastook, James L.; Head, James W.

    2014-02-01

    Crater deposit thicknesses (~50 m) cannot fill the craters in a time period compatible with the interpreted formation times of the Pedestal Crater mantled ice layers. We use a representative obliquity solution to drive an ice flow model and show that a cyclical pattern of multiply recurring layers can both fill the craters with a significant volume of ice, as well as transport debris from the crater walls out into the central regions of the craters. The cyclical pattern of waxing and waning mantling layers results in a rippled pattern of surface debris extending out into the crater interiors that would manifest itself as an observable concentric pattern, comparable in appearance to concentric crater fill. In this scenario, the formation of mantling sublimation till layers seals the accumulating ice and sequesters it from significant temperature variations at diurnal, annual and spin-axis/orbital cycle time scales, to produce ancient ice records preserved today below CCF crater floors. Lack of meltwater features associated with concentric crater fill provides evidence that the Late Amazonian climate did not exceed the melting temperature in the mid- to high-latitudes for any significant period of time. Continued sequestration of ice with time in CCF and related deposits (lobate debris aprons and lineated valley fill) further reduces the already supply-limited polar ice sources, suggesting that there has been a declining reservoir of available ice with each ensuing glacial period. Together, these deposits represent a candidate library of climate chemistry and global change dating from the Late Amazonian, and a non-polar water resource for future exploration.

  14. Diffraction patterns of the beam splitters used in a soft-x-ray interferometer with He-Ne laser

    SciTech Connect

    Oh, C. H.; Choi, D. U.; Park, S. J.; Suk, S. S.; Howells, M. R.; Hussain, Z.; Moler, E. J.; Spring, J.

    1997-04-01

    Two 50% reflection-50% transmission-grating beam splitter (B.S.) are being used in the soft x-ray interferometry at Beamline 9.3.2 of ALS. They are consisted of a rigid flat mirror with a series of slots width of 50 {mu}m etched in part (5{times}18 mm{sup 2}) of the area. The diffraction patterns of the first B.S. and both B.S.s were investigated with He-Ne laser in both cases of normal incident and 20{degrees} grazing incident to the B.S. The intensities of each diffraction pattern were measured with a radiation power meter (ORIEL 70260, 70261). The normal incident pattern is straight line and shows nearly same intervals, and the intensities of them are similar to that of the double slits with Fraunhofer diffraction theory. The diffraction patterns of grazing incident shows a circle spot line. The transmitted patterns and reflected patterns show a symmetric arc on a long distance screen, whose radii are same and confirm a modified diffraction equation. The intensities of all the fringes of the B.S. also follows to the Fraunhofer diffraction theory. Patterns of the grating were affected strongly by the single slit effect. It was observed that only 3 fringes of each pattern were illuminated on the 2nd beam splitter. For the soft x-ray ({lambda}=10 nm), the number of fringes illuminating on the 2nd B.S. was calculated from the results of He-Ne laser beam ({lambda}=632.8 nm) experiment, and showed x=0.0314 nm(fringe interval), n={+-}95.5(number of order) and therefore the total number was 191 fringes. The patterns produced by the 2nd beam splitter were also investigated in intensities and positions of them. Both patterns of upper beam and lower beam are the same direction and same radii of circle. It was found that each fringe consisted of fine fringes which as caused by two fringe beams arrived at the 2nd beam splitter.

  15. Resolution improvement and pattern generator development for the maskless micro-ion-beam reduction lithography system

    NASA Astrophysics Data System (ADS)

    Jiang, Ximan

    have been studied. The dependence of the throughput with the exposure field size and the speed of the mechanical stage has been investigated. In order to perform maskless lithography, different micro-fabricated pattern generators have been developed for the MMRL system. Ion beamlet switching has been successfully demonstrated on the MMRL system. A positive bias voltage around 10 volts is sufficient to switch off the ion current on the micro-fabricated pattern generators. Some unexpected problems, such as the high-energy secondary electron radiations, have been discovered during the experimental investigation. Thermal and structural analysis indicates that the aperture displacement error induced by thermal expansion can satisfy the 3delta CD requirement for lithography nodes down to 25 nm. The cross-talking effect near the surface and inside the apertures of the pattern generator has been simulated in a 3-D ray-tracing code. New pattern generator design has been proposed to reduce the cross-talking effect. In order to eliminate the surface charging effect caused by the secondary electrons, a new beam-switching scheme in which the switching electrodes are immersed in the plasma has been demonstrated on a mechanically fabricated pattern generator.

  16. Selective filling for patterning in microfluidic channels and integration of chromatography in "lab-on-a-chip" devices using sol-gel technology

    NASA Astrophysics Data System (ADS)

    Jindal, Rohit

    The last decade has seen tremendous advancement in the development of miniaturized chemical analysis system also known as "lab-on-a-chip". It is believed that the true potential of these devices will be achieved by integrating various functions such as separation, reaction, sensing, mixing, pumping, injection and detection onto a single chip. The ability to pattern different functionalities is indispensable for the development of highly integrated devices. In this work, a simple method based on the concept of selective filling is described for patterning in the microfluidic channels. It is based on the difference in the free energy of filling between an open and a covered part of the channel. This method was used for the integration of chromatography in the microfluidic devices. A chromatographic column was realized by utilizing sol-gel as an immobilization matrix for entrapping reversed phase chromatographic particles. Localization of the stationary phase was achieved using the selective filling technique. Channels were fabricated in quartz using photolithography and wet etching. Electroosmotic flow was used for manipulating fluid movement in the channels. Cross channel design was used for making a pulse injection of the solutes in the separation channel. An optical fiber setup was developed for carrying out on-chip UV absorbance detection. Stationary phase was created under different sol-gel synthesis conditions. It was established that the sol-gel synthesis carried out under acidic conditions provides the optimum synthesis conditions for creating separation column. Chromatographic performance of the stationary phase material was demonstrated by separating peptides present in a mixture. The sol-gel immobilization method was extended for the integration of micropump in the chip. The micropump enables pumping of the fluid in field free channels. Preliminary results, demonstrating the potential of carbon nanotubes as a support material in the microfluidic channels

  17. Advanced electron-beam pattern generation technology for 180-nm masks

    NASA Astrophysics Data System (ADS)

    Abboud, Frank E.; Sauer, Charles A.; Wang, William; Vernon, Matthew; Prior, Richard; Pearce-Percy, Henry T.; Cole, Damon M.; Mankos, Marian

    1997-02-01

    Optical lithography will be the dominant technique used for 180 nm generation production devices. With a reduced feature size on the wafer, 4X optical reduction, optical proximity correction (OPC), and phase shift lithography techniques, mask-related errors become even more critical to wafer yield. In addition, small feature sizes and lithography enhancement techniques require finer edge resolution. Clearly, new patten generation tools are needed for this generation of maskmaking requirements. Multipass gray (MPG) writing strategy was introduced with the MEBESR 4500S. The ability to deliver a 4X improvement in dose while improving throughput is a significant advantage over previous MEBES systems. Since MPG is used in conjunction with offset scan voting, reduction in butting of over 50% has been demonstrated with MPG. Higher doses are now possible with use of a multipass writing strategy and a brighter source. As a result, resists with higher contrast and process robustness can be used. A significant improvement in uniformity is noted with the new process, an essential step needed in meeting 180 nm requirements. Dry etch is essential to meet these new requirements and with sufficient process margin to be manufacturable. This paper describes the key electron-beam pattern generation technology necessary to meet the requirement of 180 nm masks, including a high dose field- emission gun and column capable of delivering 800 A/cm2; complete dynamic beam correction; a digital stage servo to provide stable, reproducible stage control under high acceleration conditions; a high speed data path to support 320 MHz beam blanking and a 10 nm data address. This paper also examines the improvements made to the MEBES platform and documents the resulting improvements and compares these results to the requirements for 180 nm masks.

  18. Ultrafast rotating dipole or propeller-shaped patterns: subwavelength shaping of a beam of light on a femtosecond time scale.

    PubMed

    Khonina, Svetlana N; Golub, Ilya

    2016-04-01

    We report on a remarkable property of azimuthally (radially) polarized light beams containing a vortex or an orbital angular momentum: upon tight focusing of a first-order vortex beam, the subwavelength spot has a shape of an electric (magnetic) dipole rotating at an optical frequency. For beams with a vortex of order m, the generated pattern is propeller-shaped and rotates at a 1/m fraction of the optical frequency. The applications include petahertz control of electrical or optical conductance between two electrodes or waveguides of two-terminal junctions.

  19. Simulation of 3-D radiation beam patterns propagated through a planar interface from ultrasonic phased array transducers.

    PubMed

    Song, Sung-Jin; Kim, Chang-Hwan

    2002-05-01

    Phased array transducers are quite often mounted on solid wedges with specific angles in many practical ultrasonic inspections of thin plates <10 mm in their thickness or welded joints with convex crowns. For the reliable application of phased array techniques with testing set-up, it is essential to have thorough understanding on the characteristics of radiation beam pattern produced in the interrogated medium. To address such a need, this paper proposes a systematic way to calculate full 3-D radiation beam patterns produced in the interrogated solid medium by phased array transducers mounted on a solid wedge. In order to investigate the characteristics of radiation beam patterns in steel, simulation is carried out for 7.5 MHz array transducers mounted on an acrylic wedge with the angle of 15.45 degrees with various of steering angles and/or focal planes.

  20. The Hydrogen Epoch of Reionization Array Dish. I. Beam Pattern Measurements and Science Implications

    NASA Astrophysics Data System (ADS)

    Neben, Abraham R.; Bradley, Richard F.; Hewitt, Jacqueline N.; DeBoer, David R.; Parsons, Aaron R.; Aguirre, James E.; Ali, Zaki S.; Cheng, Carina; Ewall-Wice, Aaron; Patra, Nipanjana; Thyagarajan, Nithyanandan; Bowman, Judd; Dickenson, Roger; Dillon, Joshua S.; Doolittle, Phillip; Egan, Dennis; Hedrick, Mike; Jacobs, Daniel C.; Kohn, Saul A.; Klima, Patricia J.; Moodley, Kavilan; Saliwanchik, Benjamin R. B.; Schaffner, Patrick; Shelton, John; Taylor, H. A.; Taylor, Rusty; Tegmark, Max; Wirt, Butch; Zheng, Haoxuan

    2016-08-01

    The Hydrogen Epoch of Reionization Array (HERA) is a radio interferometer aiming to detect the power spectrum of 21 cm fluctuations from neutral hydrogen from the epoch of reionization (EOR). Drawing on lessons from the Murchison Widefield Array and the Precision Array for Probing the EOR, HERA is a hexagonal array of large (14 m diameter) dishes with suspended dipole feeds. The dish not only determines overall sensitivity, but also affects the observed frequency structure of foregrounds in the interferometer. This is the first of a series of four papers characterizing the frequency and angular response of the dish with simulations and measurements. In this paper, we focus on the angular response (i.e., power pattern), which sets the relative weighting between sky regions of high and low delay and thus apparent source frequency structure. We measure the angular response at 137 MHz using the ORBCOMM beam mapping system of Neben et al. We measure a collecting area of 93 m2 in the optimal dish/feed configuration, implying that HERA-320 should detect the EOR power spectrum at z ˜ 9 with a signal-to-noise ratio of 12.7 using a foreground avoidance approach with a single season of observations and 74.3 using a foreground subtraction approach. Finally, we study the impact of these beam measurements on the distribution of foregrounds in Fourier space.

  1. Soft X-Ray Magnetic Imaging of Focused Ion Beam Lithographically Patterned Fe Thin Films

    SciTech Connect

    Cook, Paul J.; Shen, Tichan H.; Grundy, PhilJ.; Im, Mi Young; Fischer, Peter; Morton, Simon A.; Kilcoyne, Arthur D.L.

    2008-11-09

    We illustrate the potential of modifying the magnetic behavior and structural properties of ferromagnetic thin films using focused ion beam 'direct-write' lithography. Patterns inspired by the split-ring resonators often used as components in meta-materials were defined upon 15 nm Fe films using a 30 keV Ga{sup +} focused ion beam at a dose of 2 x 10{sup 16} ions cm{sup -2}. Structural, chemical and magnetic changes to the Fe were studied using transmission soft X-ray microscopy at the ALS, Berkeley CA. X-ray absorption spectra showed a 23% reduction in the thickness of the film in the Ga irradiated areas, but no change to the chemical environment of Fe was evident. X-ray images of the magnetic reversal process show domain wall pinning around the implanted areas, resulting in an overall increase in the coercivity of the film. Transmission electron microscopy showed significant grain growth in the implanted regions.

  2. Metalorganic molecular beam epitaxy growth of GaAs on patterned GaAs substrates

    NASA Astrophysics Data System (ADS)

    Marx, D.; Asahi, H.; Liu, X. F.; Okuno, Y.; Inoue, K.; Gonda, S.; Shimomura, S.; Hiyamizu, S.

    1994-03-01

    GaAs layers were grown on etch-patterned (100) GaAs substrates by MOMBE (metalorganic molecular beam epitaxy) using TEGa (triethylgallium) and thermally cracked TEAs (triethylarsine). Morphology and orientation dependencies of the grown facets on the growth temperature (400-630°C) and V/III ratio (2-4) are investigated. Good morphology of grown layers was obtained on (111)A side facets at a low V/III ratio of 3 and low growth temperatures of 450-500°C. We also found strong evidence that the formation of facets is not only governed by the migration of Ga precursors and/or Ga atoms, but also by a preferential catalytic decomposition of Ga precursors on the facet edges.

  3. Strategies for gallium removal after focused ion beam patterning of ferroelectric oxide nanostructures

    NASA Astrophysics Data System (ADS)

    Schilling, A.; Adams, T.; Bowman, R. M.; Gregg, J. M.

    2007-01-01

    As part of a study into the properties of ferroelectric single crystals at nanoscale dimensions, the effects that focused ion beam (FIB) processing can have, in terms of structural damage and ion implantation, on perovskite oxide materials has been examined, and a post-processing procedure developed to remove such effects. Single crystal material of the perovskite ferroelectric barium titanate (BaTiO3) has been patterned into thin film lamellae structures using a FIB microscope. Previous work had shown that FIB patterning induced gallium impregnation and associated creation of amorphous layers in a surface region of the single crystal material some 20 nm thick, but that both recrystallization and expulsion of gallium could be achieved through thermal annealing in air. Here we confirm this observation, but find that thermally induced gallium expulsion is associated with the formation of gallium-rich platelets on the surface of the annealed material. These platelets are thought to be gallium oxide. Etching using nitric and hydrochloric acids had no effect on the gallium-rich platelets. Effective platelet removal involved thermal annealing at 700 °C for 1 h in a vacuum followed by 1 h in oxygen, and then a post-annealing low-power plasma clean in an Ar/O atmosphere. Similar processing is likely to be necessary for the full recovery of post FIB-milled nanostructures in oxide ceramic systems in general.

  4. Electrical and optical characterization and nanoscale patterning of gallium nitrogen arsenide synthesized by energetic beams

    NASA Astrophysics Data System (ADS)

    Kim, Taeseok

    Two dimensionally patterned GaNxA1- x nanostructures were produced using ion implantation and pulsed laser melting followed by rapid thermal annealing. A systematic investigation of the band structure of the alloys and a nanoscale characterization of the designed band gap reduction were performed using ballistic electron emission microscopy (BEEM). The evolution of the nitrogen-concentration depth profile during the laser melting was found to be consistent with liquid-phase diffusion, solute trapping at the rapidly moving solidification front, and surface evaporation. The reduction of the Schottky barrier height of the Gamma-like threshold at nitrogen compositions up to x = 0.016 was studied with BEEM and determined quantitatively using the second voltage derivative (SD) BEEM spectra to be -191 +/- 63 meV per x = 0.01, which is close to the corresponding slope for samples grown by low-temperature molecular beam epitaxy. This slope is also consistent with the band gap narrowing measured on the same samples by photomodulated reflectance and is consistent with the band anti-crossing model for the splitting of the conduction band in GaNxAs1-x alloys. Lithographically patterned GaNxAs 1-x dots were imaged by BEEM. Analysis of BEEM spectra of the locally confined dots indicates an alloying-induced decrease in the Schottky barrier height of four times the thermal energy at room temperature.

  5. Nanohole and dot patterning processes on quartz substrate by R-θ electron beam lithography and nanoimprinting

    NASA Astrophysics Data System (ADS)

    Watanabe, Tsuyoshi; Taniguchi, Kazutake; Suzuki, Kouta; Iyama, Hiromasa; Kishimoto, Shuji; Sato, Takashi; Kobayashi, Hideo

    2016-06-01

    Fine hole and dot patterns with bit pitches (bp’s) of less than 40 nm were fabricated in the circular band area of a quartz substrate by R-θ electron beam lithography (EBL), reactive ion etching (RIE), and nanoimprinting. These patterning processes were studied to obtain minimum pitch sizes of hole and dot patterns without pattern collapse. The patterning on the circular band was aimed to apply these patterning processes to future high-density bit-patterned media (BPM) for hard disk drive (HDD) and permanent memory for the long life archiving of digital data. In hole patterning, a minimum-22-nm-bp and 8.2-nm-diameter pattern (1.3 Tbit/in.2) was obtained on a quartz substrate by optimizing the R-θ EBL and RIE processes. Dot patterns were replicated on another quartz substrate by nanoimprinting using a hole-patterned quartz substrate as a master mold followed by RIE. In dot patterning, a minimum-30-nm-bp and 18.5-nm-diameter pattern (0.7 Tbit/in.2) was obtained by introducing new descum conditions. It was observed that the minimum bp of successful patterning increased as the fabrication process proceeded, i.e., from 20 nm bp in the first EBL process to 30 nm bp in the last quartz dot patterning process. From the measured diameters of the patterns, it was revealed that pattern collapse was apt to occur when the value of average diameter plus 3 sigma of diameter was close to the bp. It was suggested that multiple fabrication processes caused the degradation of pattern quality; therefore, hole patterning is more suitable than dot patterning for future applications owing to the lower quality degradation by its simple fabrication process.

  6. The efficacy of the Self-Adjusting File versus WaveOne in removal of root filling residue that remains in oval canals after the use of ProTaper retreatment files: A cone-beam computed tomography study

    PubMed Central

    Pawar, Ajinkya M; Thakur, Bhagyashree; Metzger, Zvi; Kfir, Anda; Pawar, Mansing

    2016-01-01

    Aim: The current ex vivo study compared the efficacy of removing root fillings using ProTaper retreatment files followed by either WaveOne reciprocating file or the Self-Adjusting File (SAF). Materials and Methods: Forty maxillary canines with single oval root canal were selected and sectioned to obtain 18-mm root segments. The root canals were instrumented with WaveOne primary files, followed by obturation using warm lateral compaction, and the sealer was allowed to fully set. The teeth were then divided into two equal groups (N = 20). Initial removal of the bulk of root filling material was performed with ProTaper retreatment files, followed by either WaveOne files (Group 1) or SAF (Group 2). Endosolv R was used as a gutta-percha softener. Preoperative and postoperative high-resolution cone-beam computed tomography (CBCT) was used to measure the volume of the root filling residue that was left after the procedure. Statistical analysis was performed using t-test. Results: The mean volume of root filling residue in Group 1 was 9.4 (±0.5) mm3, whereas in Group 2 the residue volume was 2.6 (±0.4) mm3, (P < 0.001; t-test). Conclusions: When SAF was used after ProTaper retreatment files, significantly less root filling residue was left in the canals compared to when WaveOne was used. PMID:26957798

  7. High quality single shot diffraction patterns using ultrashort megaelectron volt electron beams from a radio frequency photoinjector.

    PubMed

    Musumeci, P; Moody, J T; Scoby, C M; Gutierrez, M S; Bender, H A; Wilcox, N S

    2010-01-01

    Single shot diffraction patterns using a 250-fs-long electron beam have been obtained at the UCLA Pegasus laboratory. High quality images with spatial resolution sufficient to distinguish closely spaced peaks in the Debye-Scherrer ring pattern have been recorded by scattering the 1.6 pC 3.5 MeV electron beam generated in the rf photoinjector off a 100-nm-thick Au foil. Dark current and high emittance particles are removed from the beam before sending it onto the diffraction target using a 1 mm diameter collimating hole. These results open the door to the study of irreversible phase transformations by single shot MeV electron diffraction.

  8. High quality single shot diffraction patterns using ultrashort megaelectron volt electron beams from a radio frequency photoinjector

    SciTech Connect

    Musumeci, P.; Moody, J. T.; Scoby, C. M.; Gutierrez, M. S.; Bender, H. A.; Wilcox, N. S.

    2010-01-15

    Single shot diffraction patterns using a 250-fs-long electron beam have been obtained at the UCLA Pegasus laboratory. High quality images with spatial resolution sufficient to distinguish closely spaced peaks in the Debye-Scherrer ring pattern have been recorded by scattering the 1.6 pC 3.5 MeV electron beam generated in the rf photoinjector off a 100-nm-thick Au foil. Dark current and high emittance particles are removed from the beam before sending it onto the diffraction target using a 1 mm diameter collimating hole. These results open the door to the study of irreversible phase transformations by single shot MeV electron diffraction.

  9. High Quality Single Shot Diffraction Patterns Using Ultrashort Megaelectron Volt Electron Beams from a Radio Frequency Photoinjector

    SciTech Connect

    P. Musumeci, J. T. Moody, C. M. Scoby, M. S. Gutierrez, H. A. Bender, N. S. Wilcox

    2010-01-01

    Single shot diffraction patterns using a 250 fs long electron beam have been obtained at the UCLA Pegasus laboratory. High quality images with spatial resolution sufficient to distinguish closely spaced peaks in the Debye-Scherrer ring pattern have been recorded by scattering the 1.6 pC 3.5 MeV electron beam generated in the RF photoinjector off a 100 nm thick Au foil. Dark current and high emittance particles are removed from the beam before sending it onto the diffraction target using a 1 mm diameter collimating hole. These results open the door to the study of irreversible phase transformations by single shot MeV electron diffraction

  10. The range and intensity of backscattered electrons for use in the creation of high fidelity electron beam lithography patterns.

    PubMed

    Czaplewski, David A; Holt, Martin V; Ocola, Leonidas E

    2013-08-02

    We present a set of universal curves that predict the range and intensity of backscattered electrons which can be used in conjunction with electron beam lithography to create high fidelity nanoscale patterns. The experimental method combines direct write dose, backscattered dose, and a self-reinforcing pattern geometry to measure the dose provided by backscattered electrons to a nanoscale volume on the substrate surface at various distances from the electron source. Electron beam lithography is used to precisely control the number and position of incident electrons on the surface of the material. Atomic force microscopy is used to measure the height of the negative electron beam lithography resist. Our data shows that the range and the intensity of backscattered electrons can be predicted using the density and the atomic number of any solid material, respectively. The data agrees with two independent Monte Carlo simulations without any fitting parameters. These measurements are the most accurate electron range measurements to date.

  11. In vivo visualization method by absolute blood flow velocity based on speckle and fringe pattern using two-beam multipoint laser Doppler velocimetry

    NASA Astrophysics Data System (ADS)

    Kyoden, Tomoaki; Naruki, Shoji; Akiguchi, Shunsuke; Ishida, Hiroki; Andoh, Tsugunobu; Takada, Yogo; Momose, Noboru; Homae, Tomotaka; Hachiga, Tadashi

    2016-08-01

    Two-beam multipoint laser Doppler velocimetry (two-beam MLDV) is a non-invasive imaging technique able to provide an image of two-dimensional blood flow and has potential for observing cancer as previously demonstrated in a mouse model. In two-beam MLDV, the blood flow velocity can be estimated from red blood cells passing through a fringe pattern generated in the skin. The fringe pattern is created at the intersection of two beams in conventional LDV and two-beam MLDV. Being able to choose the depth position is an advantage of two-beam MLDV, and the position of a blood vessel can be identified in a three-dimensional space using this technique. Initially, we observed the fringe pattern in the skin, and the undeveloped or developed speckle pattern generated in a deeper position of the skin. The validity of the absolute velocity value detected by two-beam MLDV was verified while changing the number of layers of skin around a transparent flow channel. The absolute velocity value independent of direction was detected using the developed speckle pattern, which is created by the skin construct and two beams in the flow channel. Finally, we showed the relationship between the signal intensity and the fringe pattern, undeveloped speckle, or developed speckle pattern based on the skin depth. The Doppler signals were not detected at deeper positions in the skin, which qualitatively indicates the depth limit for two-beam MLDV.

  12. Direct patterning of vortex generators on a fiber tip using a focused ion beam.

    PubMed

    Vayalamkuzhi, Pramitha; Bhattacharya, Shanti; Eigenthaler, Ulrike; Keskinbora, Kahraman; Samlan, C T; Hirscher, Michael; Spatz, Joachim P; Viswanathan, Nirmal K

    2016-05-15

    The realization of spiral phase optical elements on the cleaved end of an optical fiber by focused ion beam milling is presented. A focused Ga+ ion beam with an acceleration voltage of 30 keV is used to etch continuous spiral phase plates and fork gratings directly on the tip of the fiber. The phase characteristics of the output beam generated by the fabricated structures measured via an interference experiment confirmed the presence of phase singularity in the output beam. The devices are expected to be promising candidates for all-fiber beam shaping and optical trapping applications.

  13. Micro-metric electronic patterning of a topological band structure using a photon beam

    NASA Astrophysics Data System (ADS)

    Golden, Mark; Frantzeskakis, Emmanouil; de Jong, Nick; Huang, Yingkai; Wu, Dong; Pan, Yu; de Visser, Anne; van Heumen, Erik; van Bay, Tran; Zwartsenberg, Berend; Pronk, Pieter; Varier Ramankutty, Shyama; Tytarenko, Alona; Xu, Nan; Plumb, Nick; Shi, Ming; Radovic, Milan; Varkhalov, Andrei

    2015-03-01

    The only states crossing EF in ideal, 3D TIs are topological surface states. Single crystals of Bi2Se3andBi2Te3 are too defective to exhibit bulk-insulating behaviour, and ARPES shows topologically trivial 2DEGs at EF in the surface region due to downward band bending. Ternary & quaternary alloys of Bi /Te /Se /Sb hold promise for obtaining bulk-insulating crystals. Here we report ARPES data from quaternary, bulk-insulating, Bi-based TIs. Shortly after cleavage in UHV, downward band bending pulls the bulk conduction band below EF, once again frustrating the ``topological only'' ambition for the Fermi surface. However, there is light at the end of the tunnel: we show that a super-band-gap photon beam generates a surface photovoltage sufficient to flatten the bands, thereby recovering the ideal, ``topological only'' situation. In our bulk-insulating quaternary TIs, this effect is local in nature, and permits the writing of arbitrary, micron-sized patterns in the topological energy landscape at the surface. Support from FOM, NWO and the EU is gratefully acknowledged.

  14. Fluorescence of quantum dots on e-beam patterned and DNA origami substrates

    NASA Astrophysics Data System (ADS)

    Corrigan, Timothy D.; Kessinger, Matthew; Kidd, Jesse; Neff, David; Rahman, Masudur; Norton, Michael L.

    2015-05-01

    Attachment of quantum dots or fluorescent molecules to gold nanoparticles has a variety of optical labeling and sensory applications. In this study, we use both e-beam lithography and DNA origami to examine the fluorescence enhancement of fluorescent molecules and quantum dots with a systematic approach to understanding the contribution of gold nanoparticle size and interparticle spacing. The unique design of our patterns allows us to study the effects of size and spacing of the gold nanoparticles on the enhancement of fluorescence in one quick study with constant conditions - removing undesirable effects such as differences in concentration of quantum dots or other chemistry differences that plague multiple experiments. We also discuss the fluorescence and bonding of CdSe/ZnS quantum dots to both gold as well as DNA for use in self assembled DNA constructs. Specifically, bioconjugated CdSe/ZnS core/shell quantum dots were synthesized and functionalized with MPA using both traditional ligand exchange as well as newly developed in situ functionalization techniques used to increase the quantum yield of the quantum dots. We will present fluorescent images showing results of optimal size and spacing for fluorescence as well as demonstrating attachment chemistry of the quantum dots.

  15. Formation of Ga droplets on patterned GaAs (100) by molecular beam epitaxy.

    PubMed

    Li, Ming-Yu; Hirono, Yusuke; Koukourinkova, Sabina D; Sui, Mao; Song, Sangmin; Kim, Eun-Soo; Lee, Jihoon; Salamo, Gregory J

    2012-10-03

    In this paper, the formation of Ga droplets on photo-lithographically patterned GaAs (100) and the control of the size and density of Ga droplets by droplet epitaxy using molecular beam epitaxy are demonstrated. In extension of our previous result from the journal Physical Status Solidi A, volume 209 in 2012, the sharp contrast of the size and density of Ga droplets is clearly observed by high-resolution scanning electron microscope, atomic force microscope, and energy dispersive X-ray spectrometry. Also, additional monolayer (ML) coverage is added to strength the result. The density of droplets is an order of magnitude higher on the trench area (etched area), while the size of droplets is much larger on the strip top area (un-etched area). A systematic variation of ML coverage results in an establishment of the control of size and density of Ga droplets. The cross-sectional line profile analysis and root mean square roughness analysis show that the trench area (etched area) is approximately six times rougher. The atomic surface roughness is suggested to be the main cause of the sharp contrast of the size and density of Ga droplets and is discussed in terms of surface diffusion.

  16. Rigorous electromagnetic field simulation of two-beam interference exposures for the exploration of double patterning and double exposure scenarios

    NASA Astrophysics Data System (ADS)

    Erdmann, Andreas; Evanschitzky, Peter; Fühner, Tim; Schnattinger, Thomas; Xu, Cheng-Bai; Szmanda, Chuck

    2008-03-01

    The introduction of double patterning and double exposure technologies, especially in combination with hyper NA, increases the importance of wafer topography phenomena. Rigorous electromagnetic field (EMF) simulations of two beam interference exposures over non-planar wafers are used to explore the impact of the hardmask material and pattern on resulting linewidths and swing curves after the second lithography step. Moreover, the impact of the optical material contrast between the frozen and unfrozen resist in a pattern freezing process and the effect of a reversible contrast enhancement layer on the superposition of two subsequent lithographic exposures are simulated. The described simulation approaches can be used for the optimization of wafer stack configurations for double patterning and to identify appropriate optical material properties for alternative double patterning and double exposure techniques.

  17. Efficacy of Twisted File Adaptive, Reciproc and ProTaper Universal Retreatment instruments for root-canal-filling removal: A cone-beam computed tomography study.

    PubMed

    Akbulut, Makbule Bilge; Akman, Melek; Terlemez, Arslan; Magat, Guldane; Sener, Sevgi; Shetty, Heeresh

    2016-01-01

    The aim of this study was to evaluate the efficacy of Twisted File (TF) Adaptive, Reciproc, and ProTaper Universal Retreatment (UR) System instruments for removing root-canal-filling. Sixty single rooted teeth were decoronated, instrumented and obturated. Preoperative CBCT scans were taken and the teeth were retreated with TF Adaptive, Reciproc, ProTaper UR, or hand files (n=15). Then, the teeth were rescanned, and the percentage volume of the residual root-canal-filling material was established. The total time for retreatment was recorded, and the data was statistically analyzed. The statistical ranking of the residual filling material volume was as follows: hand file=TF Adaptive>ProTaper UR=Reciproc. The ProTaper UR and Reciproc systems required shorter periods of time for retreatment. Root canal filling was more efficiently removed by using Reciproc and ProTaper UR instruments than TF Adaptive instruments and hand files. The TF Adaptive system was advantageous over hand files with regard to operating time.

  18. Two-photon polymerization of microstructures by a non-diffraction multifoci pattern generated from a superposed Bessel beam.

    PubMed

    Yang, Liang; Qian, Dongdong; Xin, Chen; Hu, Zhijiang; Ji, Shengyun; Wu, Dong; Hu, Yanlei; Li, Jiawen; Huang, Wenhao; Chu, Jiaru

    2017-02-15

    In this Letter, superposed Bessel beams (SBBs) are realized by alternatively imprinting holograms of opposite-order Bessel beams along the radial direction on a spatial light modulator. The propagation invariance and non-rotation properties of SBBs are theoretically predicted and experimentally demonstrated. The focusing property of SBBs with a high numerical aperture (NA) objective is investigated with the Debye vectorial diffraction theory. Near the focal plane, a circularly distributed multiple foci pattern is achieved. The multiple foci generated from SBBs are adopted in a two-photon fabrication system, and micropattern fabrication by a single exposure is demonstrated. Facile fabrication of three-dimensional microstructures with SBBs is realized by dynamically controlling the number of focal spots, and the diameter and rotation of the focal pattern.

  19. Direct periodic patterning of GaN-based light-emitting diodes by three-beam interference laser ablation

    SciTech Connect

    Kim, Jeomoh; Ji, Mi-Hee; Detchprohm, Theeradetch; Yuan, Dajun; Guo, Rui; Liu, Jianping; Asadirad, Mojtaba; Kwon, Min-Ki; Dupuis, Russell D.; Das, Suman; Ryou, Jae-Hyun

    2014-04-07

    We report on the direct patterning of two-dimensional periodic structures in GaN-based light-emitting diodes (LEDs) through laser interference ablation for the fast and reliable fabrication of periodic micro- and nano-structures aimed at enhancing light output. Holes arranged in a two-dimensional hexagonal lattice array having an opening size of 500 nm, depth of 50 nm, and a periodicity of 1 μm were directly formed by three-beam laser interference without photolithography or electron-beam lithography processes. The laser-patterned LEDs exhibit an enhancement in light output power of 20% compared to conventional LEDs having a flat top surface without degradation of electrical and optical properties of the top p-GaN layer and the active region, respectively.

  20. Effects of competitive prey capture on flight behavior and sonar beam pattern in paired big brown bats, Eptesicus fuscus.

    PubMed

    Chiu, Chen; Reddy, Puduru Viswanadha; Xian, Wei; Krishnaprasad, Perinkulam S; Moss, Cynthia F

    2010-10-01

    Foraging and flight behavior of echolocating bats were quantitatively analyzed in this study. Paired big brown bats, Eptesicus fuscus, competed for a single food item in a large laboratory flight room. Their sonar beam patterns and flight paths were recorded by a microphone array and two high-speed cameras, respectively. Bats often remained in nearly classical pursuit (CP) states when one bat is following another bat. A follower can detect and anticipate the movement of the leader, while the leader has the advantage of gaining access to the prey first. Bats in the trailing position throughout the trial were more successful in accessing the prey. In this study, bats also used their sonar beam to monitor the conspecific's movement and to track the prey. Each bat tended to use its sonar beam to track the prey when it was closer to the worm than to another bat. The trailing bat often directed its sonar beam toward the leading bat in following flight. When two bats flew towards each other, they tended to direct their sonar beam axes away from each other, presumably to avoid signal jamming. This study provides a new perspective on how echolocating bats use their biosonar system to coordinate their flight with conspecifics in a group and how they compete for the same food source with conspecifics.

  1. Patterned ion beam implantation of Co ions into a SiO2 thin film via ordered nanoporous alumina masks.

    PubMed

    Guan, Wei; Ghatak, Jay; Peng, Yong; Peng, Nianhua; Jeynes, Chris; Inkson, Beverley; Möbus, Günter

    2012-02-03

    Spatially patterned ion beam implantation of 190 keV Co(+) ions into a SiO(2) thin film on a Si substrate has been achieved by using nanoporous anodic aluminum oxide with a pore diameter of 125 nm as a mask. The successful synthesis of periodic embedded Co regions using pattern transfer is demonstrated for the first time using cross-sectional (scanning) transmission electron microscopy (TEM) in combination with analytical TEM. Implanted Co regions are found at the correct relative lateral periodicity given by the mask and at a depth of about 120 nm.

  2. Gas-Filled Capillary Model

    NASA Astrophysics Data System (ADS)

    Steinhauer, L. C.; Kimura, W. D.

    2006-11-01

    We have developed a 1-D, quasi-steady-state numerical model for a gas-filled capillary discharge that is designed to aid in selecting the optimum capillary radius in order to guide a laser beam with the required intensity through the capillary. The model also includes the option for an external solenoid B-field around the capillary, which increases the depth of the parabolic density channel in the capillary, thereby allowing for propagation of smaller laser beam waists. The model has been used to select the parameters for gas-filled capillaries to be utilized during the Staged Electron Laser Acceleration — Laser Wakefield (STELLA-LW) experiment.

  3. Spontaneous decoration of Au nanoparticles on micro-patterned reduced graphene oxide shaped by focused laser beam

    SciTech Connect

    Wan, Y. C.; Tok, E. S.; Teoh, H. F.; Sow, C. H.

    2015-02-07

    We report a facile, two-step method for the micro-landscaping of Au nanoparticles(NPs) on reduced graphene oxide (rGO) film en route to micro-patterned Au(NPs)-rGO hybrid functional materials. This method employs a focused laser beam to first locally convert GO to rGO before immersing the micro-patterned GO-rGO film into HAuCl{sub 4} solution. The rGO micro-pattern, shaped by the focused laser beam, serves as nucleation sites for the reduction of Au ions. The reduction mechanism that governs the decoration of Au NPs on rGO films is akin to electroless deposition process. In this instance, surface charges that are formed during laser reduction of GO to rGO provide active nucleation sites for Au{sup 3+} ions to form Au NPs when HAuCl{sub 4} solution is introduced. The number density, the size, and size distribution of the Au NPs can thus be directly tuned and preferentially anchored onto the rGO micro-pattern by varying the incident laser power, the scanning speed of the laser, or the concentration of HAuCl{sub 4}. The resulting hybrid materials can be used as a substrate for Surface Enhanced Raman Spectroscopy (SERS). Using Rhodamine 6G as the test subject, we found an improvement of SERS enhancement over bare rGO of up to four times, depending on the size of the Au NPs.

  4. Simulations and measurements of beam loss patterns at the CERN Large Hadron Collider

    NASA Astrophysics Data System (ADS)

    Bruce, R.; Assmann, R. W.; Boccone, V.; Bracco, C.; Brugger, M.; Cauchi, M.; Cerutti, F.; Deboy, D.; Ferrari, A.; Lari, L.; Marsili, A.; Mereghetti, A.; Mirarchi, D.; Quaranta, E.; Redaelli, S.; Robert-Demolaize, G.; Rossi, A.; Salvachua, B.; Skordis, E.; Tambasco, C.; Valentino, G.; Weiler, T.; Vlachoudis, V.; Wollmann, D.

    2014-08-01

    The CERN Large Hadron Collider (LHC) is designed to collide proton beams of unprecedented energy, in order to extend the frontiers of high-energy particle physics. During the first very successful running period in 2010-2013, the LHC was routinely storing protons at 3.5-4 TeV with a total beam energy of up to 146 MJ, and even higher stored energies are foreseen in the future. This puts extraordinary demands on the control of beam losses. An uncontrolled loss of even a tiny fraction of the beam could cause a superconducting magnet to undergo a transition into a normal-conducting state, or in the worst case cause material damage. Hence a multistage collimation system has been installed in order to safely intercept high-amplitude beam protons before they are lost elsewhere. To guarantee adequate protection from the collimators, a detailed theoretical understanding is needed. This article presents results of numerical simulations of the distribution of beam losses around the LHC that have leaked out of the collimation system. The studies include tracking of protons through the fields of more than 5000 magnets in the 27 km LHC ring over hundreds of revolutions, and Monte Carlo simulations of particle-matter interactions both in collimators and machine elements being hit by escaping particles. The simulation results agree typically within a factor 2 with measurements of beam loss distributions from the previous LHC run. Considering the complex simulation, which must account for a very large number of unknown imperfections, and in view of the total losses around the ring spanning over 7 orders of magnitude, we consider this an excellent agreement. Our results give confidence in the simulation tools, which are used also for the design of future accelerators.

  5. Study of pattern transition in nanopatterned Si(100) produced by impurity-assisted low-energy ion-beam erosion

    NASA Astrophysics Data System (ADS)

    Koyiloth Vayalil, Sarathlal; Gupta, Ajay; Roth, Stephan V.

    2017-04-01

    In this work, formation of self-organized Si nanostructures induced by pure Fe incorporation during normal incidence low-energy (1keV) Ar^+ ion bombardment is presented. It has been observed that the incorporation of Fe affects the evolution of the surface topography. The addition of Fe generates pronounced nanopatterns, such as dots, ripples and combinations of dots and ripples. The orientation of the ripple wave vector of the patterns formed is found to be in a direction normal to the Fe flow. The nanoripples with wavelength of the order of 39 nm produced is expected to be the lowest wavelength of the patterns reported on ion-beam-eroded structures under the incorporation of metallic impurities as per our knowledge. From the AFM and GISAXS analysis, it has been confirmed that the ripples formed are asymmetric in nature. The effect of the concentration of the Fe on morphological transition of the patterns has been studied using Rutherford backscattering measurements.

  6. Interference patterns in the Spacelab 2 plasma wave data - oblique electrostatic waves generated by the electron beam

    SciTech Connect

    Feng, Wei; Gurnett, D.A.; Cairns, I.H. )

    1992-11-01

    During the Spacelab 2 mission the University of Iowa's Plasma Diagnostics Package (PDP) explored the plasma environment around the shuttle. Wideband spectrograms of plasma waves were obtained from the PDP at frequencies of 0-30 kHz and at distances up to 400 m from the shuttle. Strong low-frequency (below 10 kHz) electric field noise was observed in the wideband data during two periods in which an electron beam was ejected from the shuttle. This noise shows clear evidence of interference patterns caused by the finite (3.89 m) antenna length. The low-frequency noise was the most dominant type of noise produced by the ejected electron beam. Analysis of antenna interference patterns generated by these waves permits a determination of the wavelength, the direction of propagation, and the location of the source region. The observed waves have a linear dispersion relation very similar to that of ion acoustic waves. The waves are believed to be oblique ion acoustic or high-order ion cyclotron waves generated by a current of ambient electrons returning to the shuttle in response to the ejected electron beam. 31 refs.

  7. Controllable light diffraction in woodpile photonic crystals filled with liquid crystal

    SciTech Connect

    Ho, Chih-Hua; Zeng, Hao; Wiersma, Diederik S.; Cheng, Yu-Chieh; Maigyte, Lina; Trull, Jose; Cojocaru, Crina; Staliunas, Kestutis

    2015-01-12

    An approach to switching between different patterns of light beams transmitted through the woodpile photonic crystals filled with liquid crystals is proposed. The phase transition between the nematic and isotropic liquid crystal states leads to an observable variation of the spatial pattern transmitted through the photonic structure. The transmission profiles in the nematic phase also show polarization sensibility due to refractive index dependence on the field polarization. The experimental results are consistent with a numerical calculation by Finite Difference Time Domain method.

  8. Kinetic Monte Carlo simulation of self-organized pattern formation induced by ion beam sputtering using crater functions

    NASA Astrophysics Data System (ADS)

    Yang, Zhangcan; Lively, Michael A.; Allain, Jean Paul

    2015-02-01

    The production of self-organized nanostructures by ion beam sputtering has been of keen interest to researchers for many decades. Despite numerous experimental and theoretical efforts to understand ion-induced nanostructures, there are still many basic questions open to discussion, such as the role of erosion or curvature-dependent sputtering. In this work, a hybrid MD/kMC (molecular dynamics/kinetic Monte Carlo) multiscale atomistic model is developed to investigate these knowledge gaps, and its predictive ability is validated across the experimental parameter space. This model uses crater functions, which were obtained from MD simulations, to model the prompt mass redistribution due to single-ion impacts. Defect migration, which is missing from previous models that use crater functions, is treated by a kMC Arrhenius method. Using this model, a systematic study was performed for silicon bombarded by Ar+ ions of various energies (100 eV, 250 eV, 500 eV, 700 eV, and 1000 eV) at incidence angles of 0∘ to 80∘. The simulation results were compared with experimental findings, showing good agreement in many aspects of surface evolution, such as the phase diagram. The underestimation of the ripple wavelength by the simulations suggests that surface diffusion is not the main smoothening mechanism for ion-induced pattern formation. Furthermore, the simulated results were compared with moment-description continuum theory and found to give better results, as the simulation did not suffer from the same mathematical inconsistencies as the continuum model. The key finding was that redistributive effects are dominant in the formation of flat surfaces and parallel-mode ripples, but erosive effects are dominant at high angles when perpendicular-mode ripples are formed. Ion irradiation with simultaneous sample rotation was also simulated, resulting in arrays of square-ordered dots. The patterns obtained from sample rotation were strongly correlated to the rotation speed and to

  9. Proton beam writing of microstructures in Agar gel for patterned cell growth

    NASA Astrophysics Data System (ADS)

    Larisch, Wolfgang; Koal, Torsten; Werner, Ronald; Hohlweg, Marcus; Reinert, Tilo; Butz, Tilman

    2011-10-01

    A rather useful prerequisite for many biological and biophysical studies, e.g., for cell-cell communication or neuronal networks, is confined cell growth on micro-structured surfaces. Solidified Agar layers have smooth surfaces which are electrically neutral and thus inhibit receptor binding and cell adhesion. For the first time, Agar microstructures have been manufactured using proton beam writing (PBW). In the irradiated Agar material the polysaccharides are split into oligosaccharides which can easily be washed off leaving Agar-free areas for cell adhesion. The beam diameter of 1 μm allows the fabrication of compartments accommodating single cells which are connected by micrometer-sized channels. Using the external beam the production process is very fast. Up to 50 Petri dishes can be produced per day which makes this technique very suitable for biological investigations which require large throughputs.

  10. Focused ion beam patterned Fe thin films A study by selective area Stokes polarimetry and soft x-Ray microscopy

    SciTech Connect

    Cook, P. J.; Shen, T. H.; Grundy, P. J.; Im, M.-Y.; Fischer, P.; Morton, S. A.; Kilcoyne, A. L. D.

    2010-11-14

    We demonstrate the potential to modify the magnetic behavior and structural properties of ferromagnetic thin films using focused ion beam 'direct-write' lithography. Patterns inspired by the split-ring resonators often used as components in meta-materials were defined upon 15 nm Fe films using a 30 keV Ga{sup +} focused ion beam at a dose of 2 x 10{sup 16} ions cm{sup -2}. Structural, chemical and magnetic changes to the Fe were studied using transmission soft X-ray microscopy at the ALS, Berkeley CA. X-ray absorption spectra showed a 23% reduction in the thickness of the film in the Ga irradiated areas, but no chemical change to the Fe was evident. X-ray images of the magnetic reversal process show domain wall pinning around the implanted areas, resulting in an overall increase in the coercivity of the film. Transmission electron microscopy showed significant grain growth in the implanted regions.

  11. Dielectric-thickness dependence of damage induced by electron-beam irradiation of MNOS gate pattern

    NASA Astrophysics Data System (ADS)

    Matsui, Miyako; Mine, Toshiyuki; Hozawa, Kazuyuki; Watanabe, Kikuo; Inoue, Jiro; Nagaishi, Hiroshi

    2007-03-01

    We analyzed the electron-irradiation damage induced by electron-beam inspection of MNOS capacitors with various gate-dielectric thicknesses. Damage induced in a MNOS capacitor with SiON dielectric for high-performance CMOS devices was compared with that induced on a MOS capacitor with SiO II dielectric. We found that there is no remarkable difference between the damage to MOS capacitors and that to MNOS capacitors. The induced damage strongly depends on the thickness of the gate dielectric. Damages were induced when a higher-energy electron-beam, whose electron range was larger than the thickness of the gate electrode, was irradiated. When the electron beam was irradiated to a MOS capacitor with gate-dielectric thickness of 10.0 nm the flat-band-voltage shifted due to the created traps. When the electron beam was scanned to a MOS or MNOS capacitor with gate-dielectric thickness of 4.0 nm, Vfb shifted by less than 6 mV. However, the leakage-current density increased to 10 -7 A/cm2 at gate-electrode voltage of 3.0 V. On the other hand, when the electron beam was scanned on a MNOS capacitor with 2.5-nm-thick SiON dielectric, even the leakage current density was not increased. Accordingly, for damage-free inspection when gate-dielectric thickness is 4.0 nm or more, the electron-beam energy should be lower so that the electron range is smaller than the thickness of the gate electrode.

  12. Chemical patterning of Ag(111): Spatially confined oxide formation induced by electron beam irradiation

    SciTech Connect

    Guenther, S.; Reichelt, R.; Wintterlin, J.; Barinov, A.; Mentes, T. O.; Nino, M. A.; Locatelli, A.

    2008-12-08

    Low energy electron irradiation of a Ag(111) surface during NO{sub 2} adsorption at 300 K induces formation of Ag oxide. Using a spatially confined electron beam, small Ag{sub 2}O spots could be grown with a sharp, {approx}100 nm wide, boundary to the nonirradiated metallic surface. Since the structure size will mainly depend on the sharpness of the irradiating electron beam, this process has the potential of a single step nanostructuring process. Temperature treatment offers an easy way to manipulate the boundary between oxide and metallic silver by steering a chemical front.

  13. Third-dimension information retrieval from a single convergent-beam transmission electron diffraction pattern using an artificial neural network

    NASA Astrophysics Data System (ADS)

    Pennington, Robert S.; Van den Broek, Wouter; Koch, Christoph T.

    2014-05-01

    We have reconstructed third-dimension specimen information from convergent-beam electron diffraction (CBED) patterns simulated using the stacked-Bloch-wave method. By reformulating the stacked-Bloch-wave formalism as an artificial neural network and optimizing with resilient back propagation, we demonstrate specimen orientation reconstructions with depth resolutions down to 5 nm. To show our algorithm's ability to analyze realistic data, we also discuss and demonstrate our algorithm reconstructing from noisy data and using a limited number of CBED disks. Applicability of this reconstruction algorithm to other specimen parameters is discussed.

  14. Surface pattern formation during MeV energy ion beam irradiation

    SciTech Connect

    Srivastava, S. K.; Nair, K. G. M.; Kannan, R. Kamala; Kamruddin, M.; Panigrahi, B. K.; Tyagi, A. K.

    2012-06-05

    Surface patterning during high energy heavy ion irradiation is a relatively recent observation. We report in this paper the results of a study on the formation of self organized ripple patterns on silica surface irradiated with MeV energy gold ions.

  15. Exploring the origin of charging-induced pattern positioning errors in mask making using e-beam lithography

    NASA Astrophysics Data System (ADS)

    Chen, Chien-Cheng; Liu, Tzu-Ling; Chang, Shao-Wen; Ho, Yen-Cheng; Chen, Chia-Jen; Lin, Chih-Cheng; Lien, Ta-Cheng; Lee, Hsin-Chang; Yen, Anthony

    2015-10-01

    The authors present a detailed observation of the charge-induced pattern positioning errors (CIPPEs) in a variableshape e-beam writer on an opaque-MoSi-over-glass (OMOG) mask by directly measuring the pattern shifts using a mask registration tool. The CIPPEs are found to have one short-range, that is exponentially decaying in space, and the other constant offset components. The exponential term that decays slowly in time, whereas the constant offset fast diminishes. By applying a charge dissipation layer (CDL), the authors experimentally verify that the exponential component results from the charges in resist. On the other hands, the constant offset that can not be eliminated by the CDL is speculated to be charges in the substrate according to the Monte Carlo simulation.

  16. Reconfigurable Near-Field Beam Pattern Measurement System From 0.03 to 1.6 THz

    NASA Astrophysics Data System (ADS)

    Gonzalez, Alvaro; Fujii, Yasunori; Kojima, Takafumi; Asayama, Shin'ichiro

    2016-03-01

    With the discovery and utilization of great observation sites, on-ground radio astronomical observations have been extended from the millimeter-wave (mm-wave) range to around 1.6 THz. The radiation collected by the telescope reflector antenna is coupled to the receiver by means of the receiver optics. These optics must be designed to match the in-coming fields from the telescope and properly characterized by amplitude and phase measurements. This paper presents a reconfigurable near-field beam pattern measurement system which can characterize magnitude and phase patterns of antennas and optics from the mm-wave to the THz region. Measurements at 900 GHz and 1.37 THz are presented for two different configurations, using different phase-lock components, and measured under cryogenic and room-temperature conditions, respectively.

  17. Focused Ion Beam patterning of suspended graphene for cantilever and kirigami devices

    NASA Astrophysics Data System (ADS)

    Rose, Peter; Huang, Pinshane; Blees, Melina; Barnard, Arthur; Muller, David; McEuen, Paul

    2014-03-01

    We have developed techniques that use a Focused Ion Beam (FIB) to cut and manipulate suspended graphene. Using a dual-beam FIB, we can make cuts with a resolution of tens of nanometers, manipulate and pick up finished devices using a micromanipulator, and remove device and micromanipulator from the vacuum chamber. Remarkably, we have demonstrated that singly clamped graphene cantilevers can be fabricated reliably and are robust enough to be freely manipulated in air. This gives us the potential to perform novel electrostatic and mechanical measurements of graphene. Using the FIB's direct writing capabilities, we are also able to cut out more complex shapes, drawing inspiration from kirigami, the art of paper cutting. Using specific cuts, we can create soft in-plane springs, which might be used to study tension. This exploration of the fabrication and manipulation of graphene in three dimensions is a promising new avenue toward harnessing graphene's unique properties, and also holds promise for other 2D materials.

  18. Controlled modulation of laser beam and dynamic patterning of colloidal particles using optical tweezers

    NASA Astrophysics Data System (ADS)

    Singh, Brijesh Kumar; Singh Mehta, Dalip; Kumar, Ranjeet; Senthilkumaran, Paramasivam

    2016-02-01

    We present controlled generation of complex-structured beam profiles using diffractive optical element and demonstrate multiple dynamic trapping of colloidal particles. The phase element is programmed to generate various tailored optical fields having structures, similar to that of number three, spiral, and circle but in a tractable manner. Thus, the generated spatially tailored optical fields are confined to focal volume in optical tweezers. This enabled real-time trapping of multiple microscopic objects whereby its transverse organization was controlled in a dynamic manner from one structure to another with the help of spatial light modulator. Such a controlled beam shaping finds potential applications in biophotonics, super resolution imaging, and measurement of biophysical parameters, cell sorting, and micro-manipulation of colloidal particles.

  19. Massively parallel E-beam inspection: enabling next-generation patterned defect inspection for wafer and mask manufacturing

    NASA Astrophysics Data System (ADS)

    Malloy, Matt; Thiel, Brad; Bunday, Benjamin D.; Wurm, Stefan; Mukhtar, Maseeh; Quoi, Kathy; Kemen, Thomas; Zeidler, Dirk; Eberle, Anna Lena; Garbowski, Tomasz; Dellemann, Gregor; Peters, Jan Hendrik

    2015-03-01

    SEMATECH aims to identify and enable disruptive technologies to meet the ever-increasing demands of semiconductor high volume manufacturing (HVM). As such, a program was initiated in 2012 focused on high-speed e-beam defect inspection as a complement, and eventual successor, to bright field optical patterned defect inspection [1]. The primary goal is to enable a new technology to overcome the key gaps that are limiting modern day inspection in the fab; primarily, throughput and sensitivity to detect ultra-small critical defects. The program specifically targets revolutionary solutions based on massively parallel e-beam technologies, as opposed to incremental improvements to existing e-beam and optical inspection platforms. Wafer inspection is the primary target, but attention is also being paid to next generation mask inspection. During the first phase of the multi-year program multiple technologies were reviewed, a down-selection was made to the top candidates, and evaluations began on proof of concept systems. A champion technology has been selected and as of late 2014 the program has begun to move into the core technology maturation phase in order to enable eventual commercialization of an HVM system. Performance data from early proof of concept systems will be shown along with roadmaps to achieving HVM performance. SEMATECH's vision for moving from early-stage development to commercialization will be shown, including plans for development with industry leading technology providers.

  20. Noise temperature and beam pattern of an NbN hot electron bolometer mixer at 5.25 THz

    NASA Astrophysics Data System (ADS)

    Zhang, W.; Khosropanah, P.; Gao, J. R.; Bansal, T.; Klapwijk, T. M.; Miao, W.; Shi, S. C.

    2010-11-01

    We report the measured sensitivities of a superconducting NbN hot electron bolometer (HEB) heterodyne receiver at 5.25 THz. Terahertz (THz) radiation is quasioptically coupled to a HEB mixer with a lens and a spiral antenna. Using a measurement setup with black body calibration sources and a beam splitter in vacuo, and an antireflection coated Si lens, we obtained a double sideband (DSB) receiver noise temperature (TrecDSB) of 1150 K, which is nine times hν/2k, where h is the Planck constant, ν the frequency, and k the Boltzmann constant. In addition, the measured far field beam patterns of the integrated lens antenna show nearly collimated beams from 2.5 to 5.3 THz that allow reliable measurement of TrecDSB using the vacuum setup. Our experimental results in combination with an antenna-to-bolometer coupling simulation suggest that the HEB mixer can work well at least up to 6 THz, making it suitable for next generation of high-resolution spectroscopic space telescopes and, in particular, for the detection of the neutral atomic oxygen line at 4.7 THz.

  1. Frequency-dependent variation in the two-dimensional beam pattern of an echolocating dolphin

    PubMed Central

    Starkhammar, Josefin; Moore, Patrick W.; Talmadge, Lois; Houser, Dorian S.

    2011-01-01

    Recent recordings of dolphin echolocation using a dense array of hydrophones suggest that the echolocation beam is dynamic and can at times consist of a single dominant peak, while at other times it consists of forward projected primary and secondary peaks with similar energy, partially overlapping in space and frequency bandwidth. The spatial separation of the peaks provides an area in front of the dolphin, where the spectral magnitude slopes drop off quickly for certain frequency bands. This region is potentially used to optimize prey localization by directing the maximum pressure slope of the echolocation beam at the target, rather than the maximum pressure peak. The dolphin was able to steer the beam horizontally to a greater extent than previously described. The complex and dynamic sound field generated by the echolocating dolphin may be due to the use of two sets of phonic lips as sound sources, or an unknown complexity in the sound propagation paths or acoustic properties of the forehead tissues of the dolphin. PMID:21561965

  2. The role of carbon in ion beam nano-patterning of silicon

    NASA Astrophysics Data System (ADS)

    Bhattacharjee, S.; Karmakar, P.; Naik, V.; Sinha, A. K.; Chakrabarti, A.

    2013-10-01

    We report a comparative study of nano-pattern formations on a carbon film and a smooth Si(100) surface following inert and chemically active ion bombardment. For the case of carbon film, patterns could be formed both by inert (Ar+) and self (C+) ion bombardment with the former producing ripples at relatively lower fluence. In contrast, bombardment by inert Ar+ failed to form the nano patterns on Si surface, while bombardment by the same energy C+ generated the ripples. Thus, impurity induced chemical effect seems to be crucial rather than the Bradley-Harper or Carter-Vishnyakov effects for destabilizing the surface for ripple formation.

  3. Toward Two-Dimensional All-Carbon Heterostructures via Ion Beam Patterning of Single-Layer Graphene.

    PubMed

    Kotakoski, Jani; Brand, Christian; Lilach, Yigal; Cheshnovsky, Ori; Mangler, Clemens; Arndt, Markus; Meyer, Jannik C

    2015-09-09

    Graphene has many claims to fame: it is the thinnest possible membrane, it has unique electronic and excellent mechanical properties, and it provides the perfect model structure for studying materials science at the atomic level. However, for many practical studies and applications the ordered hexagon arrangement of carbon atoms in graphene is not directly suitable. Here, we show that the atoms can be locally either removed or rearranged into a random pattern of polygons using a focused ion beam (FIB). The atomic structure of the disordered regions is confirmed with atomic-resolution scanning transmission electron microscopy images. These structural modifications can be made on macroscopic scales with a spatial resolution determined only by the size of the ion beam. With just one processing step, three types of structures can be defined within a graphene layer: chemically inert graphene, chemically active amorphous 2D carbon, and empty areas. This, along with the changes in properties, gives promise that FIB patterning of graphene will open the way for creating all-carbon heterostructures to be used in fields ranging from nanoelectronics and chemical sensing to composite materials.

  4. Theoretical study of fabrication of line-and-space patterns with 7 nm quarter-pitch using electron beam lithography with chemically amplified resist process: V. Optimum beam size

    NASA Astrophysics Data System (ADS)

    Kozawa, Takahiro

    2016-10-01

    The high-volume production of semiconductor devices with sub-10 nm critical dimensions is challenging. We have investigated the feasibility of the fabrication of line-and-space patterns with a 7 nm quarter-pitch (7 nm space width and 21 nm line width) by electron beam (EB) lithography. In this study, the optimum beam size for the fabrication of line-and-space patterns with a 7 nm quarter-pitch was investigated from the viewpoint of the trade-off relationship between line edge roughness (LER) and sensitivity. When the peak charge was constant, the optimum beam size depended on the required sensitivity. When the total charge was constant, the beam size was required to be less than 1.6 nm for minimizing LER.

  5. Acoustic beam steering by light refraction: illustration with directivity patterns of a tilted volume photoacoustic source.

    PubMed

    Raetz, Samuel; Dehoux, Thomas; Perton, Mathieu; Audoin, Bertrand

    2013-12-01

    The symmetry of a thermoelastic source resulting from laser absorption can be broken when the direction of light propagation in an elastic half-space is inclined relatively to the surface. This leads to an asymmetry of the directivity patterns of both compressional and shear acoustic waves. In contrast to classical surface acoustic sources, the tunable volume source allows one to take advantage of the mode conversion at the surface to control the directivity of specific modes. Physical interpretations of the evolution of the directivity patterns with the increasing light angle of incidence and of the relations between the preferential directions of compressional- and shear-wave emission are proposed. In order to compare calculated directivity patterns with measurements of normal displacement amplitudes performed on plates, a procedure is proposed to transform the directivity patterns into pseudo-directivity patterns representative of the experimental conditions. The comparison of the theoretical with measured pseudo-directivity patterns demonstrates the ability to enhance bulk-wave amplitudes and to steer specific bulk acoustic modes by adequately tuning light refraction.

  6. Beam delivery and pulse compression to sub-50 fs of a modelocked thin-disk laser in a gas-filled Kagome-type HC-PCF fiber.

    PubMed

    Emaury, Florian; Dutin, Coralie Fourcade; Saraceno, Clara J; Trant, Mathis; Heckl, Oliver H; Wang, Yang Y; Schriber, Cinia; Gerome, Frederic; Südmeyer, Thomas; Benabid, Fetah; Keller, Ursula

    2013-02-25

    We present two experiments confirming that hypocycloid Kagome-type hollow-core photonic crystal fibers (HC-PCFs) are excellent candidates for beam delivery of MW peak powers and pulse compression down to the sub-50 fs regime. We demonstrate temporal pulse compression of a 1030-nm Yb:YAG thin disk laser providing 860 fs, 1.9 µJ pulses at 3.9 MHz. Using a single-pass grating pulse compressor, we obtained a pulse duration of 48 fs (FWHM), a spectral bandwidth of 58 nm, and an average output power of 4.2 W with an overall power efficiency into the final polarized compressed pulse of 56%. The pulse energy was 1.1 µJ. This corresponds to a peak power of more than 10 MW and a compression factor of 18 taking into account the exact temporal pulse profile measured with a SHG FROG. The compressed pulses were close to the transform limit of 44 fs. Moreover, we present transmission of up to 97 µJ pulses at 10.5 ps through 10-cm long fiber, corresponding to more than twice the critical peak power for self-focusing in silica.

  7. Quantitative testing of physiotherapy ultrasound beam patterns within a clinical environment using a thermochromic tile.

    PubMed

    Žauhar, Gordana; Radojčić, Đeni Smilović; Dobravac, Denis; Jurković, Slaven

    2015-04-01

    The implementation of the non-standardized method developed at the National Physical Laboratory (UK) supporting the quality assurance of therapeutic ultrasonic beam parameters within a clinical environment is presented. The method consists of exposing an acoustic absorber tile, part of which contains a thermochromic pigment, to the ultrasonic beam, thereby forming an image of the two-dimensional intensity profile of the transducer. Nine different physiotherapy ultrasound treatment heads currently used clinically were tested using this method. Thermochromic images were postprocessed in order to estimate the Effective Radiating Area (ERA) for treatment heads operating within the frequency range from 1 MHz to 3.2 MHz, and nominal applied intensities in the range of 1-3 W/cm(2). Experimental results and comparisons with manufacturer specified values of ERA are presented. Differences in the experimentally derived results and the manufacturer values are typically well within 25%. The root-mean squared difference calculated over the nine treatment heads is 15.1%, with the thermochromic material tended to underestimate the ERA.

  8. Electron Beam Lifetime in SPEAR3: Measurement and Simulation

    SciTech Connect

    Corbett, J.; Huang, X.; Lee, M.; Lui, P.; Sayyar-Rodsari, B.; /Pavilon Tech., Austin

    2007-12-19

    In this paper we report on electron beam lifetime measurements as a function of scraper position, RF voltage and bunch fill pattern in SPEAR3. We then outline development of an empirical, macroscopic model using the beam-loss rate equation. By identifying the dependence of loss coefficients on accelerator and beam parameters, a numerically-integrating simulator can be constructed to compute beam decay with time. In a companion paper, the simulator is used to train a parametric, non-linear dynamics model for the system [1].

  9. Utility of Megavoltage Fan-Beam CT for Treatment Planning in a Head-And-Neck Cancer Patient with Extensive Dental Fillings Undergoing Helical Tomotherapy

    SciTech Connect

    Yang, Claus; Liu Tianxiao; Jennelle, Richard L.; Ryu, Janice K.; Vijayakumar, Srinivasan; Purdy, James A.; Chen, Allen M.

    2010-07-01

    The purpose of this study was to demonstrate the potential utility of megavoltage fan-beam computed tomography (MV-FBCT) for treatment planning in a patient undergoing helical tomotherapy for nasopharyngeal carcinoma in the presence of extensive dental artifact. A 28-year-old female with locally advanced nasopharyngeal carcinoma presented for radiation therapy. Due to the extensiveness of the dental artifact present in the oral cavity kV-CT scan acquired at simulation, which made treatment planning impossible on tomotherapy planning system, MV-FBCT imaging was obtained using the HI-ART tomotherapy treatment machine, with the patient in the treatment position, and this information was registered with her original kV-CT scan for the purposes of structure delineation, dose calculation, and treatment planning. To validate the feasibility of the MV-FBCT-generated treatment plan, an electron density CT phantom (model 465, Gammex Inc., Middleton, WI) was scanned using MV-FBCT to obtain CT number to density table. Additionally, both a 'cheese' phantom (which came with the tomotherapy treatment machine) with 2 inserted ion chambers and a generic phantom called Quasar phantom (Modus Medical Devices Inc., London, ON, Canada) with one inserted chamber were used to confirm dosimetric accuracy. The MV-FBCT could be used to clearly visualize anatomy in the region of the dental artifact and provide sufficient soft-tissue contrast to assist in the delineation of normal tissue structures and fat planes. With the elimination of the dental artifact, the MV-FBCT images allowed more accurate dose calculation by the tomotherapy system. It was confirmed that the phantom material density was determined correctly by the tomotherapy MV-FBCT number to density table. The ion chamber measurements agreed with the calculations from the MV-FBCT generated phantom plan within 2%. MV-FBCT may be useful in radiation treatment planning for nasopharyngeal cancer patients in the setting of extensive

  10. Resolution Improvement and Pattern Generator Development for theMaskless Micro-Ion-Beam Reduction Lithography System

    SciTech Connect

    Jiang, Ximan

    2006-05-18

    have been studied. The dependence of the throughput with the exposure field size and the speed of the mechanical stage has been investigated. In order to perform maskless lithography, different micro-fabricated pattern generators have been developed for the MMRL system. Ion beamlet switching has been successfully demonstrated on the MMRL system. A positive bias voltage around 10 volts is sufficient to switch off the ion current on the micro-fabricated pattern generators. Some unexpected problems, such as the high-energy secondary electron radiations, have been discovered during the experimental investigation. Thermal and structural analysis indicates that the aperture displacement error induced by thermal expansion can satisfy the 3δ CD requirement for lithography nodes down to 25 nm. The cross-talking effect near the surface and inside the apertures of the pattern generator has been simulated in a 3-D ray-tracing code. New pattern generator design has been proposed to reduce the cross-talking effect. In order to eliminate the surface charging effect caused by the secondary electrons, a new beam-switching scheme in which the switching electrodes are immersed in the plasma has been demonstrated on a mechanically fabricated pattern generator.

  11. Ion beam induced surface patterns due to mass redistribution and curvature-dependent sputtering

    NASA Astrophysics Data System (ADS)

    Bobes, Omar; Zhang, Kun; Hofsäss, Hans

    2012-12-01

    Recently it was reported that ion-induced mass redistribution would solely determine nano pattern formation on ion-irradiated surfaces. We investigate the pattern formation on amorphous carbon thin films irradiated with Xe ions of energies between 200 eV and 10 keV. Sputter yield as well as number of displacements within the collision cascade vary strongly as function of ion energy and allow us to investigate the contributions of curvature-dependent erosion according to the Bradley-Harper model as well as mass redistribution according to the Carter-Vishnyakov model. We find parallel ripple orientations for an ion incidence angle of 60° and for all energies. A transition to perpendicular pattern orientation or a rather flat surface occurs around 80° for energies between 1 keV and 10 keV. Our results are compared with calculations based on both models. For the calculations we extract the shape and size of Sigmund's energy ellipsoid (parameters a, σ, μ), the angle-dependent sputter yield, and the mean mass redistribution distance from the Monte Carlo simulations with program SDTrimSP. The calculated curvature coefficients Sx and Sy describing the height evolution of the surface show that mass redistribution is dominant for parallel pattern formation in the whole energy regime. Furthermore, the angle where the parallel pattern orientation starts to disappear is related to curvature-dependent sputtering. In addition, we investigate the case of Pt erosion with 200 eV Ne ions, where mass redistribution vanishes. In this case, we observe perpendicular ripple orientation in accordance with curvature-dependent sputtering and the predictions of the Bradley-Harper model.

  12. Hybrid deburring process assisted by a large pulsed electron beam (LPEB) for laser-fabricated patterned metal masks

    NASA Astrophysics Data System (ADS)

    Kim, Jisoo; Park, Hyung Wook

    2015-12-01

    The quality of pixels on displays and semiconductors is directly related to the surface quality of the patterned metal mask used. Burrs generated on the patterned metal mask can degrade the quality of pixels on microelectronic devices during the deposition process. In this study, experimental observations of abrasive deburring along with large pulsed electron beam (LPEB) irradiation were performed to evaluate the deburring effects on patterned metal masks. Numerical modeling of LPEB irradiation approximately predicted melting depths and the experimental studies revealed limitations in the size of burrs removed by LPEB irradiation. Thus a LPEB-assisted hybrid deburring process was developed to eliminate burrs of metal masks regardless of their size. The size of burrs remaining after the LPEB-assisted hybrid deburring process was reduced to approximately 7.2 μm which was much less than the results of abrasive deburring alone (38.01 μm). The burr size distribution was reduced by 85% and surface roughness (Ra) was decreased from 640 nm to 121 nm, indicating a uniform surface texture.

  13. Focused-ion-beam overlay-patterning of three-dimensional diamond structures for advanced single-photon properties

    SciTech Connect

    Jiang, Qianqing; Liu, Dongqi; Liu, Gangqin; Chang, Yanchun; Li, Wuxia E-mail: czgu@aphy.iphy.ac.cn; Pan, Xinyu; Gu, Changzhi E-mail: czgu@aphy.iphy.ac.cn

    2014-07-28

    Sources of single photons are of fundamental importance in many applications as to provide quantum states for quantum communication and quantum information processing. Color centers in diamond are prominent candidates to generate and manipulate quantum states of light, even at room temperature. However, the efficiency of photon collection of the color centers in bulk diamond is greatly reduced by refraction at the diamond/air interface. To address this issue, diamond structuring has been investigated by various methods. Among them, focused-ion-beam (FIB) direct patterning has been recognized as the most favorable technique. But it has been noted that diamond tends to present significant challenges in FIB milling, e.g., the susceptibility of forming charging related artifacts and topographical features. In this work, periodically-positioned-rings and overlay patterning with stagger-superimposed-rings were proposed to alleviate some problems encountered in FIB milling of diamond, for improved surface morphology and shape control. Cross-scale network and uniform nanostructure arrays have been achieved in single crystalline diamond substrates. High quality diamond solid immersion lens and nanopillars were sculptured with a nitrogen-vacancy center buried at the desired position. Compared with the film counterpart, an enhancement of about ten folds in single photon collection efficiency was achieved with greatly improved signal to noise ratio. All these results indicate that FIB milling through over-lay patterning could be an effective approach to fabricate diamond structures, potentially for quantum information studies.

  14. Ferromagnetic resonance response of electron-beam patterned arrays of ferromagnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Jung, Sukkoo; Watkins, Byron; Feller, Jeffrey; Ketterson, John; Chandrasekhar, Venkat

    2001-03-01

    We report on the fabrication and the dynamic magnetic properties of periodic permalloy dot arrays. Electron-beam lithography and e-gun evaporation have been used to make the arrays with the aspect ratio of 2 (dot diameter : 40 nm, height : 80 nm) and periods of 100 - 200 nm. The magnetic properties of the arrays and their interactions have been investigated by ferromagnetic resonance (FMR), magnetic force microscopy (MFM), and SQUID magnetometry. The measured FMR data show that the position and magnitude of resonant absorption peaks strongly depend on the angle between magnetic field and the lattice structure. The results of dot arrays with various kinds of structural parameters will be presented. Supported by Army Research Office, DAAD19-99-1-0334/P001

  15. Simulation of motorcycle crashes with w-beam guardrail: injury patterns and analysis.

    PubMed

    Ibitoye, A B; Hamouda, A M S; Wong, S V; Umar, R S Radin

    2009-11-01

    This study uses computer simulations to study the impact of a motorcycle with the conventional w-beam guardrail. A three-dimensional computer simulation of a scaled hybrid III 50th-percentile male dummy mounted on a motorcycle and colliding with a w-beam guardrail is carried out. A multi-body model of the motorcycle and finite element model of the guardrail are developed using commercially available software. The simulation model is validated with a physical crash test conducted with same initial impact configurations. Impacts at speeds of 32, 48, and 60 km/h at an impact angle at 45 degrees are considered. The predicted forces and accelerations are compared with the biomechanical limits for each body part and the risk of injury to the rider are evaluated. Speed was found to have a significant influence on the level of injury to the head, neck, chest, and femur. A significant reduction of the severity of injuries was found when the impact speed was reduced from 60 to 32km/h. The accelerations experienced by the head and chest are found to be higher than safe levels for impact speeds of 48 and 60 km/h. The biomechanical limit for the right femur is exceeded at all three considered impact speeds. Neck injuries are also a concern, with the predicted tension values and neck bending extent being higher than the biomechanical limit for the 60 km/h impact speed. In light of these results, it is suggested that the design of guardrails should be reviewed with a focus on the safety of motorcyclists.

  16. Analysis of splitting patterns from Stern-Gerlach magnetic deflection of supersonic molecular beams: application to M J -state-resolved deflection of J=2 atoms

    NASA Astrophysics Data System (ADS)

    Weiser, C.; Siska, P. E.

    1988-06-01

    Measurements of M J -state resolved Stern-Gerlach deflection patterns for the3 P 2 states of noble gas metastable atoms in supersonic beams are analyzed using a modification of the method originally worked out by Otto Stern. Velocity distribution breadth and beam collimation required to resolve the M J states are explored, and the modeling is improved by including variation in the field gradient along the deflected atomic trajectories.

  17. High-efficiency broad-area single-quantum-well lasers with narrow single-lobed far-field patterns prepared by molecular beam epitaxy

    NASA Technical Reports Server (NTRS)

    Larsson, A.; Muttelstein, M.; Arakawa, Y.; Yariv, A.

    1986-01-01

    Broad-area single-quantum-well graded-index waveguide separate-confinement heterostructure lasers were fabricated by molecular beam epitaxy. A high external quantum efficiency of 79 percent and stable, single-lobed far-field patterns with a beam divergence as narrow as 0.8 deg (1.9 times diffraction limit) for a 100 micron-wide laser were obtained under pulsed conditions.

  18. Increased pattern transfer fidelity ZEP 520A during reactive ion etching through chemical modifications by additional dosing of the electron beam resist.

    SciTech Connect

    Czaplewski, D. A.; Ocola, L. E.

    2011-03-01

    This article describes a postdevelopment, additional electron exposure to enhance the etch selectivity and improve pattern transfer fidelity of an electron beam resist, ZEP 520A, through chemical changes of the resist. After the critical features were patterned and developed, the resist was exposed at 5 kV accelerating voltage to a second dose of electrons ranging from 300 to 300,000 {micro}C/cm{sup 2}. The etch rate of the resist decreased by approximately 25% in a CHF{sub 3} and O{sub 2} plasma. More critically, the fidelity of the pattern transfer was improved. Infrared and Raman spectroscopies were used to characterize the resist before and after electron beam exposure for doses up to 3000 {micro}C/cm{sup 2}. The carbonyl bonding in the polymer showed significant changes after electron beam exposure that can be associated with improvement in the etch performance of this resist.

  19. Travel-time sensitivity kernels versus diffraction patterns obtained through double beam-forming in shallow water.

    PubMed

    Iturbe, Ion; Roux, Philippe; Virieux, Jean; Nicolas, Barbara

    2009-08-01

    In recent years, the use of sensitivity kernels for tomographic purposes has been frequently discussed in the literature. Sensitivity kernels of different observables (e.g., amplitude, travel-time, and polarization for seismic waves) have been proposed, and relationships between adjoint formulation, time-reversal theory, and sensitivity kernels have been developed. In the present study, travel-time sensitivity kernels (TSKs) are derived for two source-receiver arrays in an acoustic waveguide. More precisely, the TSKs are combined with a double time-delay beam-forming algorithm performed on two source-receiver arrays to isolate and identify each eigenray of the multipath propagation between a source-receiver pair in the acoustic waveguide. A relationship is then obtained between TSKs and diffraction theory. It appears that the spatial shapes of TSKs are equivalent to the gradients of the combined direction patterns of the source and receiver arrays. In the finite-frequency regimes, the combination of TSKs and double beam-forming both simplifies the calculation of TSK and increases the domain of validity for ray theory in shallow-water ocean acoustic tomography.

  20. Electron-beam patterned self-assembled monolayers as templates for Cu electrodeposition and lift-off

    PubMed Central

    She, Zhe; DiFalco, Andrea; Hähner, Georg

    2012-01-01

    Summary Self-assembled monolayers (SAMs) of 4'-methylbiphenyl-4-thiol (MBP0) adsorbed on polycrystalline gold substrates served as templates to control electrochemical deposition of Cu structures from acidic solution, and enabled the subsequent lift-off of the metal structures by attachment to epoxy glue. By exploiting the negative-resist behaviour of MBP0, the SAM was patterned by means of electron-beam lithography. For high deposition contrast a two-step procedure was employed involving a nucleation phase around −0.7 V versus Cu2+/Cu and a growth phase at around −0.35 V versus Cu2+/Cu. Structures with features down to 100 nm were deposited and transferred with high fidelity. By using substrates with different surface morphologies, AFM measurements revealed that the roughness of the substrate is a crucial factor but not the only one determining the roughness of the copper surface that is exposed after lift-off. PMID:22428101

  1. In situ patterning of organic molecules in aqueous solutions using an inverted electron-beam lithography system

    NASA Astrophysics Data System (ADS)

    Miyazako, Hiroki; Ishihara, Kazuhiko; Mabuchi, Kunihiko; Hoshino, Takayuki

    2016-06-01

    A method for in situ controlling the detachment and deposition of organic molecules such as sugars and biocompatible polymers in aqueous solutions by electron-beam (EB) scan is proposed and evaluated. It was demonstrated that EB irradiation could detach 2-methacryloyloxyethyl phosphorylcholine (MPC) polymers from a silicon nitride membrane. Moreover, organic molecules such as cationic polymers and sugars could be deposited on the membrane by EB irradiation. Spatial distributions of scattered electrons were numerically simulated, and acceleration voltage dependences of the detachment and deposition phenomena were experimentally measured. The simulations and experimental results suggest that the detachment of MPC polymers is mainly due to electrical effects of primary electrons, and that the deposition of organic molecules is mainly due to chemical reactions induced by primary electrons. In view of these findings, the proposed method can be applied to in situ and nanoscale patterning such as the fabrication of cell scaffolds.

  2. Optical characterization of GaAs pyramid microstructures formed by molecular beam epitaxial regrowth on pre-patterned substrates

    SciTech Connect

    Pritchard, R. E.; Oulton, R. F.; Stavrinou, P. N.; Parry, G.; Williams, R. S.; Ashwin, M. J.; Neave, J. H.; Jones, T. S.

    2001-07-01

    Arrays of GaAs pyramids with square (001) bases of length 1{endash}5 {mu}m have been fabricated by molecular beam epitaxy regrowth on pre-patterned GaAs (001) substrates. The optical properties of the pyramid faces have been studied by microreflection and microtransmission imaging measurements with light ({lambda}=900{endash}1000nm) incident through the pyramid base. Digitized charge coupled device images indicate that total internal reflection occurs at the {l_brace}110{r_brace} pyramid facets and that their reflectivities are greater than 80%, provided overgrowth of the facets does not occur. These properties suggest that such structures may be suitable as the top mirror in novel micron-scale vertical microcavity devices. {copyright} 2001 American Institute of Physics.

  3. Influence of template fill in graphoepitaxy DSA

    NASA Astrophysics Data System (ADS)

    Doise, Jan; Bekaert, Joost; Chan, Boon Teik; Hong, SungEun; Lin, Guanyang; Gronheid, Roel

    2016-03-01

    Directed self-assembly (DSA) of block copolymers (BCP) is considered a promising patterning approach for the 7 nm node and beyond. Specifically, a grapho-epitaxy process using a cylindrical phase BCP may offer an efficient solution for patterning randomly distributed contact holes with sub-resolution pitches, such as found in via and cut mask levels. In any grapho-epitaxy process, the pattern density impacts the template fill (local BCP thickness inside the template) and may cause defects due to respectively over- or underfilling of the template. In order to tackle this issue thoroughly, the parameters that determine template fill and the influence of template fill on the resulting pattern should be investigated. In this work, using three process flow variations (with different template surface energy), template fill is experimentally characterized as a function of pattern density and film thickness. The impact of these parameters on template fill is highly dependent on the process flow, and thus pre-pattern surface energy. Template fill has a considerable effect on the pattern transfer of the DSA contact holes into the underlying layer. Higher fill levels give rise to smaller contact holes and worse critical dimension uniformity. These results are important towards DSA-aware design and show that fill is a crucial parameter in grapho-epitaxy DSA.

  4. Optical Nanoscopy of High Tc Cuprate Nanoconstriction Devices Patterned by Helium Ion Beams

    NASA Astrophysics Data System (ADS)

    Gozar, A.; Litombe, N. E.; Hoffman, Jennifer E.; Božović, I.

    2017-03-01

    Helium-ion beams (HIB) focused to sub-nanometer scales have emerged as powerful tools for high-resolution imaging as well as nano-scale lithography, ion milling or deposition. Quantifying irradiation effects is essential for reliable device fabrication but most of the depth profiling information is provided by computer simulations rather than experiment. Here, we use atomic force microscopy (AFM) combined with scanning near-field optical microscopy (SNOM) to provide three-dimensional (3D) dielectric characterization of high-temperature superconductor devices fabricated by HIB. By imaging the infrared dielectric response we find that amorphization caused by the nominally 0.5 nm HIB extends throughout the entire 26.5 nm thickness of the cuprate film and by about 500 nm laterally. This unexpectedly widespread structural and electronic damage can be attributed to a Helium depth distribution substantially modified by internal device interfaces. Our study introduces AFM-SNOM as a quantitative nano-scale tomographic technique for non-invasive 3D characterization of irradiation damage in a wide variety of devices.

  5. Micro-metric electronic patterning of a topological band structure using a photon beam

    PubMed Central

    Frantzeskakis, E.; De Jong, N.; Zwartsenberg, B.; Huang, Y. K.; Bay, T. V.; Pronk, P.; Van Heumen, E.; Wu, D.; Pan, Y.; Radovic, M.; Plumb, N. C.; Xu, N.; Shi, M.; De Visser, A.; Golden, M. S.

    2015-01-01

    In an ideal 3D topological insulator (TI), the bulk is insulating and the surface conducting due to the existence of metallic states that are localized on the surface; these are the topological surface states. Quaternary Bi-based compounds of Bi2−xSbxTe3−ySey with finely-tuned bulk stoichiometries are good candidates for realizing ideal 3D TI behavior due to their bulk insulating character. However, despite its insulating bulk in transport experiments, the surface region of Bi2−xSbxTe3−ySey crystals cleaved in ultrahigh vacuum also exhibits occupied states originating from the bulk conduction band. This is due to adsorbate-induced downward band-bending, a phenomenon known from other Bi-based 3D TIs. Here we show, using angle-resolved photoemission, how an EUV light beam of moderate flux can be used to exclude these topologically trivial states from the Fermi level of Bi1.46Sb0.54Te1.7Se1.3 single crystals, thereby re-establishing the purely topological character of the low lying electronic states of the system. We furthermore prove that this process is highly local in nature in this bulk-insulating TI, and are thus able to imprint structures in the spatial energy landscape at the surface. We illustrate this by ‘writing’ micron-sized letters in the Dirac point energy of the system. PMID:26543011

  6. Optical nanoscopy of high Tc cuprate nanoconstriction devices patterned by helium ion beams

    DOE PAGES

    Gozar, Adrian; Litombe, N. E.; Hoffman, Jennifer E.; ...

    2017-02-06

    Helium ion beams (HIB) focused to subnanometer scales have emerged as powerful tools for high-resolution imaging as well as nanoscale lithography, ion milling, or deposition. Quantifying irradiation effects is an essential step toward reliable device fabrication, but most of the depth profiling information is provided by computer simulations rather than the experiment. Here, we demonstrate the use of atomic force microscopy (AFM) combined with scanning near-field optical microscopy (SNOM) to provide three-dimensional (3D) dielectric characterization of high-temperature superconductor devices fabricated by HIB. By imaging the infrared dielectric response obtained from light demodulation at multiple harmonics of the AFM tapping frequency,more » we find that amorphization caused by the nominally 0.5 nm HIB extends throughout the entire 26.5 nm thickness of the cuprate film and by ~500 nm laterally. This unexpectedly widespread damage in morphology and electronic structure can be attributed to a helium depth distribution substantially modified by the internal device interfaces. Lastly, our study introduces AFM-SNOM as a quantitative tomographic technique for noninvasive 3D characterization of irradiation damage in a wide variety of nanoscale devices.« less

  7. Yield components, leaf pigment contents, patterns of seed filling, dry matter, LAI and LAID of some safflower (Carthamus tinctorius L.) genotypes in Iran.

    PubMed

    Mokhtassi-Bidgoli, A; Akbari, Gh Al; Mirhadi, M J; Pazoki, A R; Soufizadeh, S

    2007-05-01

    In order to assess the genotypic variation among yield components and different physiological parameters and their relationships with safflower seed yield, six safflower genotypes were grown in Pakdasht, Iran in a randomized complete block design with four replications, during 2003-2004 growing season. Among the genotypes, chlorophyll a, chlorophyll b, chlorophyll a+b, total carotenoids contents, chlorophyll a/chlorophyll b ratio and Chlorophyll a+b/total cartenoids ratio ranged from 0.78 to 1.10, from 0.54 to 0.71, from 1.37 to 1.71, from 0.09 to 0.13 mg g(-1), from 1.33 to 1.68 and from 13.52 to 14.82, respectively. Negative relationships existed between seed yield and pigment contents. There were significant yield differences among genotypes and varied from 2452.60 to 3897.20 kg ha(-1). A diverse range of capitulum diameter (24.08-28.91 mm), seed weight/capitulum (1.18-2.04 g), number of seeds/m2 (8704.5-13165.4), number of capitula/plant (16.38-23.27), number of seeds/capitulum (35.65-41.90) and 1000-seed weight (29.94-50.60 g) was recorded. Genotypes differed in HI and the HI values ranged from 21.83% (LRK-262) to 29.62% (IL.111). In the studied set of 6 safflower genotypes, total biomass and LAI peaked around after full flowering and at the beginning of flowering, respectively. Zarghan-279 (with the greatest LAID) had 25% longer LAID than LRV.51.51 (with the lowest LAID). Differences among genotypes for rate of seed filling and effective seed filling duration were significant and differences in seed yield could be attributed to differences in the rate of seed filling. The results of this experiment indicate that physiological parameters including rate of seed filling, rapid leaf formation and expansion and delayed plant senescence are the characteristics of high-yielding safflower. Also, higher dry matter accumulation, HI, seed weight/capitulum, 1000-seed weight and capitulum diameter were found to be closely related to high-yield genotypes.

  8. Patterning, Characterization and Chemical Sensing Applications of Graphene Nanoribbon Arrays Down to 5 nm Using Helium Ion Beam Lithography

    NASA Astrophysics Data System (ADS)

    Abbas, Ahmad; Liu, Gang; Liu, Bilu; Zhang, Luyao; Liu, He; Ohlberg, Douglas; Wu, Wei; Zhou, Chongwu

    2014-03-01

    Bandgap engineering of graphene is an essential step towards employing graphene in electronic and sensing applications. Recently, graphene nanoribbons (GNRs) were used to create a bandgap in graphene and function as a semiconducting switch. Although GNRs with widths of <10 nm have been achieved, problems like GNR alignment, width control, uniformity, high aspect ratios, and edge roughness must be resolved in order to introduce GNRs as a robust alternative technology. Here we report patterning, characterization and superior chemical sensing of ultra-narrow aligned GNR arrays down to 5 nm width using helium ion beam lithography (HIBL) for the first time. The patterned GNR arrays possess narrow and adjustable widths, high aspect ratios, and relatively high quality. Field-effect transistors were fabricated on such GNR arrays and temperature-dependent transport measurements show the thermally activated carrier transport in the GNR array structure. Furthermore, we have demonstrated exceptional NO2 gas sensitivity of the 5 nm GNR array devices down to ppb levels. The results show the potential of HIBL fabricated GNRs for the electronic and sensing applications. We would like to thank HP labs for the use of helium ion microscope. We thank Professor Kang L. Wang and Stephen B. Cronin for help with some of the experiments. We acknowledge the office of Naval Research for financial support.

  9. Pattern manipulation via on-chip phase modulation between orbital angular momentum beams

    SciTech Connect

    Li, Huanlu; Strain, Michael J.; Meriggi, Laura; Sorel, Marc; Chen, Lifeng; Zhu, Jiangbo; Cicek, Kenan; Wang, Jianwei; Thompson, Mark G.; Cai, Xinlun; Yu, Siyuan

    2015-08-03

    An integrated approach to thermal modulation of relative phase between two optical vortices with opposite chirality has been demonstrated on a silicon-on-insulator substrate. The device consists of a silicon-integrated optical vortex emitter and a phase controlled 3 dB coupler. The relative phase between two optical vortices can be actively modulated on chip by applying a voltage on the integrated heater. The phase shift is shown to be linearly proportional to applied electrical power, and the rotation angle of the interference pattern is observed to be inversely proportional to topological charge. This scheme can be used in lab-on-chip, communications and sensing applications. It can be intentionally implemented with other modulation elements to achieve more complicated applications.

  10. Using Ambient Ion Beams to Write Nanostructured Patterns for Surface Enhanced Raman Spectroscopy

    SciTech Connect

    Li, Anyin; Baird, Zane; Bag, Soumabha; Sarkar, Depanjan; Prabhath, Anupama; Pradeep, Thalappil; Cooks, Robert G.

    2014-11-10

    Electrolytic spray deposition was used to pattern surfaces with 2D metallic nanostructures. Spots that contain silver nanoparticles (AgNP) were created by landing solvated silver ions at desired locations using electrically floated masks to focus the metal ions to an area as little as 20 mm in diameter. The AgNPs formed are unprotected and their aggregates can be used for surface-enhanced Raman spectroscopy (SERS). The morphology and SERS activity of the NP structures were controlled by the surface coverage of landed silver ions. The NP structures created could be used as substrates onto which SERS samples were deposited or prepared directly on top of predeposited samples of interest. The evenly distributed hot spots in the micron-sized aggregates had an average SERS enhancement factor of 108. The surfaces showed SERS activity when using lasers of different wavelengths (532, 633, and 785 nm) and were stable in air.

  11. Ion beam induced surface pattern formation and stable travelling wave solutions.

    PubMed

    Numazawa, Satoshi; Smith, Roger

    2013-03-06

    The formation of ripple structures on ion bombarded semiconductor surfaces is examined theoretically. Previous models are discussed and a new nonlinear model is formulated, based on the infinitesimal local atomic relocation induced by elastic nuclear collisions in the early stages of collision cascades and an associated density change in the near surface region. Within this framework ripple structures are shown to form without the necessity to invoke surface diffusion or large sputtering as important mechanisms. The model can also be extended to the case where sputtering is important, and it is shown that in this case certain 'magic' angles can occur at which the ripple patterns are most clearly defined. The results are in very good agreement with experimental observations.

  12. Directed immobilization of protein-coated nanospheres to nanometer-scale patterns fabricated by electron beam lithography of poly(ethylene glycol) self-assembled monolayers.

    PubMed

    Rundqvist, Jonas; Hoh, Jan H; Haviland, David B

    2006-05-23

    Controlling the spatial organization of biomolecules on solid supports with high resolution is important for a wide range of scientific and technological problems. Here we report a study of electron beam lithography (EBL) patterning of a self-assembled monolayer (SAM) of the amide-containing poly(ethylene glycol) (PEG) thiol CH(3)O(CH(2)CH(2)O)(17)NHCO(CH(2))(2)SH on Au and demonstrate the patterning of biomolecular features with dimensions approaching 40 nm. The electron dose dependence of feature size and pattern resolution is studied in detail by atomic force microscopy (AFM), which reveals two distinct patterning mechanisms. At low doses, the pattern formation occurs by SAM ablation in a self-developing process where the feature size is directly dose-dependent. At higher doses, electron beam-induced deposition of material, so-called contamination writing, is seen in the ablated areas of the SAM. The balance between these two mechanisms is shown to depend on the geometry of the pattern. The patterned SAMs were backfilled with fluorescent 40-nm spheres coated with NeutrAvidin. These protein-coated spheres adhered to exposed areas in the SAM with high selectivity. This direct writing approach for patterning bioactive surfaces is a fast and efficient way to produce patterns with a resolution approaching that of single proteins.

  13. Radical External Beam Radiotherapy for Clinically Localized Prostate Cancer in Japan: Changing Trends in the Patterns of Care Process Survey

    SciTech Connect

    Ogawa, Kazuhiko; Nakamura, Katsumasa; Sasaki, Tomonari; Onishi, Hiroshi; Koizumi, Masahiko; Araya, Masayuki; Mukumoto, Nobutaka; Teshima, Teruki; Mitsumori, Michihide

    2011-12-01

    Purpose: To delineate changing trends in radical external beam radiotherapy (EBRT) for prostate cancer in Japan. Methods and Materials: Data from 841 patients with clinically localized prostate cancer treated with EBRT in the Japanese Patterns of Care Study (PCS) from 1996 to 2005 were analyzed. Results: Significant increases in the proportions of patients with stage T1 to T2 disease and decrease in prostate-specific antigen values were observed. Also, there were significant increases in the percentages of patients treated with radiotherapy by their own choice. Median radiation doses were 65.0 Gy and 68.4 Gy from 1996 to 1998 and from 1999 to 2001, respectively, increasing to 70 Gy from 2003 to 2005. Moreover, conformal therapy was more frequently used from 2003 to 2005 (84.9%) than from 1996 to 1998 (49.1%) and from 1999 to 2001 (50.2%). On the other hand, the percentage of patients receiving hormone therapy from 2003 to 2005 (81.1%) was almost the same as that from 1996 to 1998 (86.3%) and from 1999 to 2001 (89.7%). Compared with the PCS in the United States, patient characteristics and patterns of treatments from 2003 to 2005 have become more similar to those in the United States than those from 1996 to 1998 and those from 1999 to 2001. Conclusions: This study indicates a trend toward increasing numbers of patients with early-stage disease and increasing proportions of patients treated with higher radiation doses with advanced equipment among Japanese prostate cancer patients treated with EBRT during 1996 to 2005 survey periods. Patterns of care for prostate cancer in Japan are becoming more similar to those in the United States.

  14. Length and Geometric Patterns of the Greater Palatine Canal Observed in Cone Beam Computed Tomography

    PubMed Central

    Howard-Swirzinski, Karen; Edwards, Paul C.; Saini, Tarnjit S.; Norton, Neil S.

    2010-01-01

    The greater palatine canal is an important anatomical structure that is often utilized as a pathway for infiltration of local anesthesia to affect sensation and hemostasis. Increased awareness of the length and anatomic variation in the anatomy of this structure is important when performing surgical procedures in this area (e.g., placement of osseointegrated dental implants). We examined the anatomy of the greater palatine canal using data obtained from CBCT scans of 500 subjects. Both right and left canals were viewed (N = 1000) in coronal and sagittal planes, and their paths and lengths determined. The average length of the greater palatine canal was 29 mm (±3 mm), with a range from 22 to 40 mm. Coronally, the most common anatomic pattern consisted of the canal traveling inferior-laterally for a distance then directly inferior for the remainder (43.3%). In the sagittal view, the canal traveled most frequently at an anterior-inferior angle (92.9%). PMID:20871845

  15. Range verification of passively scattered proton beams based on prompt gamma time patterns

    NASA Astrophysics Data System (ADS)

    Testa, Mauro; Min, Chul Hee; Verburg, Joost M.; Schümann, Jan; Lu, Hsiao-Ming; Paganetti, Harald

    2014-07-01

    We propose a proton range verification technique for passive scattering proton therapy systems where spread out Bragg peak (SOBP) fields are produced with rotating range modulator wheels. The technique is based on the correlation of time patterns of the prompt gamma ray emission with the range of protons delivering the SOBP. The main feature of the technique is the ability to verify the proton range with a single point of measurement and a simple detector configuration. We performed four-dimensional (time-dependent) Monte Carlo simulations using TOPAS to show the validity and accuracy of the technique. First, we validated the hadronic models used in TOPAS by comparing simulations and prompt gamma spectrometry measurements published in the literature. Second, prompt gamma simulations for proton range verification were performed for the case of a water phantom and a prostate cancer patient. In the water phantom, the proton range was determined with 2 mm accuracy with a full ring detector configuration for a dose of ~2.5 cGy. For the prostate cancer patient, 4 mm accuracy on range determination was achieved for a dose of ~15 cGy. The results presented in this paper are encouraging in view of a potential clinical application of the technique.

  16. LauePt, a graphical-user-interface program for simulating and analyzing white-beam x-ray diffraction Laue patterns.

    SciTech Connect

    Huang, X.

    2010-08-01

    LauePt is a robust and extremely easy-to-use Windows application for accurately simulating, indexing and analyzing white-beam X-ray diffraction Laue patterns of any crystals under arbitrary diffraction geometry. This program has a user-friendly graphic interface and can be conveniently used by nonspecialists with little X-ray diffraction or crystallography knowledge. Its wide range of applications include (1) determination of single-crystal orientation with the Laue method, (2) white-beam topography, (3) white-beam microdiffraction, (4) X-ray studies of twinning, domains and heterostructures, (5) verification or determination of crystal structures from white-beam diffraction, and (6) teaching of X-ray crystallography.

  17. E-beam GIDC resolution enhancement technology in practical applications

    NASA Astrophysics Data System (ADS)

    Martens, S.; Butschke, J.; Galler, R.; Krüger, M.; Sailer, H.; Sülzle, M.

    2013-09-01

    For nearly all relevant applications of e-beam lithography the resolution and pattern quality requirements are approaching or exceeding the limits of the available process. On one hand, for shrinking feature dimensions, the e-beam proximity effect and process effects such as photo acid diffusion limit the pattern contrast and process window. On the other hand, e-beam process related parasitic effects such as shot noise, fogging, developer loading, heating, charging, and inhomogeneous bake introduce some significant errors. Even though e-beam tool and process tool suppliers continue to implement new or improve current strategies to avoid or correct these effects, the amount of residual errors requires some reasonable e-beam process window, in particular for high end applications. For some patterns the undersize-overdose approach (SIZE) improves the pattern fidelity and process window. However, for patterns with high fill factors this approach increases the overall deposited electron dose, which due to the increased backscattering diminishes or even eliminates the advantages. The geometrically induced dose correction (GIDC) method overcomes this issue by combining the SIZE concept with a short range framing technique, which reduces the deposited dose in large filled pattern areas. This paper provides a comparison of the standard, SIZE, and GIDC correction approaches for 1D test patterns as well as production patterns. For a broad comparison, patterns were printed onto negative and positive chemically amplified resists and on wafer and mask substrates using a Vistec SB352HR variable shape e-beam writer. Both wafers were also etched. The outcome of the study is that the SIZE and GIDC approaches often outperform the standard proximity effect correction. For dense patterns, GIDC still provides a better pattern quality and process window, while the SIZE approach suffers from the increased overall deposited electron dose and clearly falls behind GIDC in terms of process

  18. Failure pattern implications following external beam irradiation of prostate cancer: long-term follow-up and indications of cure.

    PubMed

    Hanlon, A L; Hanks, G E

    2000-04-01

    The purpose of this study was to present patterns and risk of biochemical failure following external beam irradiation of prostate cancer and to make comparisons to a published modern radical prostatectomy series. Between January 1987 and December 1994, 328 men were treated definitively at Fox Chase Cancer Center for localized prostate cancer using conventional or three-dimensional conformal radiotherapy. The median biochemical follow-up was 6.4 years, with all patients having at least 5 years follow-up. Two prognostic patient groups were established on the basis of proportional hazards modeling that considered treatment and presenting tumor characteristics. For each of the two prognostic groups, biochemical failure and hazard functions were estimated using the ASTRO consensus definition of failure and life table methodology. Failure risk comparisons were made to modern published radical prostatectomy series. Multivariate analysis demonstrated the independent predictive power of pretreatment PSA level, palpation stage, Gleason score, and dose. Thus, the favorable prognosis group, Group I, consisted of 83 patients who were treated with a dose level > or = 74 Gy and who presented with PSA levels < 20 ng/ml, T1/T2A tumors, and Gleason score 2-6. Group II consisted of 245 patients with at least one of the following: pretreatment PSA level > or = 20 ng/ml, T2B/T3 tumor, Gleason score 7-10, dose < 74 Gy. The 5- and 8-year bNED estimates were 76% and 76% for Group I, and 51% and 49% for Group II. Only three failures occurred after 5 years, all from Group II, representing 2% of the total failures observed. Hazard function estimates indicate maximum risk of failure at 24 to 36 months, tapering to a low rate at 4 years with no failures observed after 6 years. Differences in patterns of failure by prognostic group show maximum risk of failure at 24 months (median, 31 months) for Group I, and 12 to 36 months (median, 22 months) for Group II. Group II reaches low levels of risk

  19. Space-filling percolation

    NASA Astrophysics Data System (ADS)

    Chakraborty, Abhijit; Manna, S. S.

    2014-03-01

    A region of two-dimensional space has been filled randomly with a large number of growing circular disks allowing only a "slight" overlapping among them just before their growth stops. More specifically, each disk grows from a nucleation center that is selected at a random location within the uncovered region. The growth rate δ is a continuously tunable parameter of the problem which assumes a specific value while a particular pattern of disks is generated. When a growing disk overlaps for the first time with at least one other disk, its growth is stopped and is said to be frozen. In this paper we study the percolation properties of the set of frozen disks. Using numerical simulations we present evidence for the following: (i) The order parameter appears to jump discontinuously at a certain critical value of the area coverage; (ii) the width of the window of the area coverage needed to observe a macroscopic jump in the order parameter tends to vanish as δ →0; and on the contrary (iii) the cluster size distribution has a power-law-decaying functional form. While the first two results are the signatures of a discontinuous transition, the third result is indicative of a continuous transition. Therefore we refer to this transition as a sharp but continuous transition similar to what has been observed in the recently introduced Achlioptas process of explosive percolation. It is also observed that in the limit of δ →0, the critical area coverage at the transition point tends to unity, implying that the limiting pattern is space filling. In this limit, the fractal dimension of the pore space at the percolation point has been estimated to be 1.42(10) and the contact network of the disk assembly is found to be a scale-free network.

  20. Observation of Beam ION Instability in Spear3

    SciTech Connect

    Teytelman, D.; Cai, Y.; Corbett, W.J.; Raubenheimer, T.O.; Safranek, J.A.; Schmerge, J.F.; Sebek, J.J.; Wang, L.; /SLAC

    2011-12-14

    Weak vertical coupled bunch instability with oscillation amplitude at {mu}m level has been observed in SPEAR3. The instability becomes stronger when there is a vacuum pressure rise by partially turning off vacuum pumps and it becomes weaker when the vertical beam emittance is increased by turning off the skew quadrupole magnets. These confirmed that the instability was driven by ions in the vacuum. The threshold of the beam ion instability when running with a single bunch train is just under 200 mA. This paper presents the comprehensive observations of the beam ion instability in SPEAR3. The effects of vacuum pressure, beam current, beam filling pattern, chromaticity, beam emittance and bunch-by-bunch feedback are investigated in great detail. In an electron accelerator, ions generated from the residual gas molecules can be trapped by the beam. Then these trapped ions interact resonantly with the beam and cause beam instability and emittance blow-up. Most existing light sources use a long single bunch train filling pattern, followed by a long gap to avoid multi-turn ion trapping. However, such a gap does not preclude ions from accumulating during one passage of the single bunch train beam, and those ions can still cause a Fast Ion Instability (FII) as predicted by Raubenheimer and Zimmermann. FII has been observed in ALS, and PLS by artificially increasing the vacuum pressure by injecting helium gas into the vacuum chamber or by turning off the ion pumps in order to observe the beam ion instability. In some existing rings, for instance B factory, the beam ion instability was observed at the beginning of the machine operation after a long period of shutdown and then it automatically disappeared when the vacuum was better. However, when the beam emittance becomes smaller, the FII can occur at nominal conditions as observed in PLS, SOLEIL and SSRF. This paper reports the observations of beam ion instabilities in SPEAR3 under different condition during a period of one

  1. A novel raster-scanning method to fabricate ultra-fine cross-gratings for the generation of electron beam moiré fringe patterns

    NASA Astrophysics Data System (ADS)

    Lang, F. C.; Zhao, Y. R.; Xing, Y. M.; Liu, F.; Hou, X. H.; Zhu, J.; Li, J. J.; Yang, S. T.

    2016-11-01

    The resolution of the electron beam moiré method depends on the line frequency of the grating. Recently, more and more effort has been devoted to increase the frequency, and a novel method for producing high-resolution electron beam gratings is presented in this work. Cross-gratings with a frequency up to 14,832 lines/mm (67 nm pitch) were successfully fabricated using a common scanning electron microscope without a dedicated pattern generation system. The quality of the grating was high enough to produce high-quality moiré fringe patterns. In this method, the ultra-fine cross-grating can be fabricated only through one-directional scanning on the resist, which can improve the grating quality and significantly reduces the fabrication time. The number of control parameters for grating fabrication could be reduced to two compared to the six parameters required by conventional methods, which facilitates the use of the electron beam moiré method. The frequency of the fabricated grating is linearly proportional to the exposure magnification. Thus, the frequency of the grating can be accurately predetermined, and the null field can be easily obtained in the electron beam moiré method. The quality of the fabricated gratings was illustrated by the obtained micrographs and moiré fringe patterns. The full-field local strain near an induced crack was studied to verify the application potential of this method.

  2. Measurement of Beam Lifetime and Applications for SPEAR3

    SciTech Connect

    Huang, Xiaobiao; Corbett, Jeff; /SLAC

    2011-04-05

    Beam lifetime studies for the SPEAR3 storage ring are presented. The three lifetime components are separated with lifetime measurements under various combinations of beam currents and fill patterns and vertical scraper scans. Touschek lifetime is studied with rf voltage scans and with the horizontal or vertical scrapers inserted. The measurements are explained with calculations based on the calibrated lattice model. Quantum lifetime measurements are performed with reduced longitudinal and horizontal apertures, respectively, from which we deduce the radiation energy loss down to a few keV per revolution and the horizontal beam size.

  3. Getting a prescription filled

    MedlinePlus

    ... prescription filled; Drugs - how to get prescription filled; Pharmacy - mail order; Pharmacy - internet; Types of pharmacies ... paper prescription that you take to a local pharmacy Calling or e-mailing a pharmacy to order ...

  4. An Analysis of the Far-Field Radiation Pattern of the Ultraviolet Light-Emitting Diode (LED) Engin LZ4-00UA00 Diode with and without Beam Shaping Optics

    DTIC Science & Technology

    2015-09-01

    SEP 2015 US Army Research Laboratory An Analysis of the Far-Field Radiation Pattern of the Ultraviolet Light - Emitting Diode (LED) Engin...Radiation Pattern of the Ultraviolet Light - Emitting Diode (LED) Engin LZ4-00UA00 Diode with and without Beam Shaping Optics 5a. CONTRACT NUMBER... light - emitting diode (LED), with and without beam shaping optics. This LED has 4 emitters arranged in a square pattern that are off-center from the

  5. Idler-efficiency-enhanced long-wave infrared beam generation using aperiodic orientation-patterned GaAs gratings.

    PubMed

    Gürkan Figen, Ziya; Aytür, Orhan; Arıkan, Orhan

    2016-03-20

    In this paper, we design aperiodic gratings based on orientation-patterned gallium arsenide (OP-GaAs) for converting 2.1 μm pump laser radiation into long-wave infrared (8-12 μm) in an idler-efficiency-enhanced scheme. These single OP-GaAs gratings placed in an optical parametric oscillator (OPO) or an optical parametric generator (OPG) can simultaneously phase match two optical parametric amplification (OPA) processes, OPA 1 and OPA 2. We use two design methods that allow simultaneous phase matching of two arbitrary χ(2) processes and also free adjustment of their relative strength. The first aperiodic grating design method (Method 1) relies on generating a grating structure that has domain walls located at the zeros of the summation of two cosine functions, each of which has a spatial frequency that equals one of the phase-mismatch terms of the two processes. Some of the domain walls are discarded considering the minimum domain length that is achievable in the production process. In this paper, we propose a second design method (Method 2) that relies on discretizing the crystal length with sample lengths that are much smaller than the minimum domain length and testing each sample's contribution in such a way that the sign of the nonlinearity maximizes the magnitude sum of the real and imaginary parts of the Fourier transform of the grating function at the relevant phase mismatches. Method 2 produces a similar performance as Method 1 in terms of the maximization of the height of either Fourier peak located at the relevant phase mismatch while allowing an adjustable relative height for the two peaks. To our knowledge, this is the first time that aperiodic OP-GaAs gratings have been proposed for efficient long-wave infrared beam generation based on simultaneous phase matching.

  6. Localization of a delamination and estimation of its length in a composite laminate beam by the VSHM and pattern recognition methods

    NASA Astrophysics Data System (ADS)

    Minak, G.; Palazzetti, R.; Trendafilova, I.; Zucchelli, A.

    2010-11-01

    The purpose of this study was to investigate the delamination damage in laminate composite beams in order to adapt the vibration-based structural health monitoring (VSHM) method for laminated structures. The analysis was concentrated on the vibration characteristics of laminated specimens, in particular, on the first several natural frequencies of a composite laminate beam with a delamination damage. The core of this work is an experimental investigation into the vibration response of a composite laminate beam and its changes caused by delaminations of different sizes and different location in the beam. The aim was to determine how the first six harmonic frequencies are changed by a delamination, and the results show that they can be successfully used to clarify the presence, location, and dimensions of delaminations in a composite beam. A pattern recognition analysis was used to locate the damage, while its detection and evaluation were performed by using changes in the harmonic frequencies. A finite-element analysis was carried out, and the variations in the natural frequencies due to delamination are found to be in good agreement with experimental results.

  7. Magnetic force microscopy and spinstand testing of multi-row-per-track discrete bit patterned media fabricated by focused ion beam

    NASA Astrophysics Data System (ADS)

    Chen, Y. J.; Huang, T. L.; Leong, S. H.; Hu, S. B.; Ng, K. W.; Yuan, Z. M.; Zong, B. Y.; Shi, J. Z.; Hendra, S. K.; Liu, B.; Ng, V.

    2009-04-01

    Multi-row-per-track discrete bit patterned media with interleaved bits have been fabricated on granular perpendicular media disks by focused ion beam and tested by magnetic force microscopy and spinstand tester. It was found that sub-100 nm patterned magnetic islands showed single domain behavior and narrowed switching field distribution. We further demonstrate from captured spinstand readback waveforms the concept of recording two rows of interleaved dot bits as one track. In addition to overcoming the down track patterning resolution limit, the proposed concept patterned media provide many other advantages including higher data rate for read/write, a flexible bit aspect ratio (BAR)≥2 design for better integration with head design and servo control, as well as allowing the use of wider write pole to improve writing efficiency for high density recording.

  8. Design beam shapers with double freeform surfaces to form a desired wavefront with prescribed illumination pattern by solving a Monge-Ampère type equation

    NASA Astrophysics Data System (ADS)

    Chang, Shengqian; Wu, Rengmao; An, Li; Zheng, Zhenrong

    2016-12-01

    Beam shaping, in other words, the control of both intensity distribution and phase profile, has a wide range of applications. In this paper, double freeform surfaces are utilized to shape collimated beams, realizing an arbitrary output wavefront with desired illumination pattern. Freeform surfaces are designed by solving a second order partial differential equation (PDE) of the Monge-Ampère (MA) type, without the limitation of symmetry or paraxial approximation. The mathematical derivation of the PDE is based on the Snell’s law, the energy conservation law along infinitesimal tubes of rays and the constancy of the OPL. The PDE is discretized with a finite difference scheme into a system of nonlinear equations, which can be numerically solved by Newton’s method. Since Newton’s method requires a good initialization for the iteration, a simultaneously point-by-point method, based on ray mapping, is employed to find the initial iterate. Different design examples are given to demonstrate the effectiveness and wide application of our method, transforming a collimated Gaussian beam into a spherical wavefront with uniform illumination patterns. Variable-sized uniform illumination pattern can be obtained by moving the observation plane due to a potential benefit of the spherical output wavefront.

  9. Self-organised silicide nanodot patterning by medium-energy ion beam sputtering of Si(100): local correlation between the morphology and metal content

    NASA Astrophysics Data System (ADS)

    Redondo-Cubero, A.; Galiana, B.; Lorenz, K.; Palomares, FJ; Bahena, D.; Ballesteros, C.; Hernandez-Calderón, I.; Vázquez, L.

    2016-11-01

    We have produced self-organised silicide nanodot patterns by medium-energy ion beam sputtering (IBS) of silicon targets with a simultaneous and isotropic molybdenum supply. Atomic force microscopy (AFM) studies show that these patterns are qualitatively similar to those produced thus far at low ion energies. We have determined the relevance of the ion species on the pattern ordering and properties. For the higher ordered patterns produced by Xe+ ions, the pattern wavelength depends linearly on the ion energy. The dot nanostructures are silicide-rich as assessed by x-ray photoelectron spectroscopy (XPS) and emerge in height due to their lower sputtering yield, as observed by electron microscopy. Remarkably, a long wavelength corrugation is observed on the surface which is correlated with both the Mo content and the dot pattern properties. Thus, as assessed by electron microscopy, the protrusions are Mo-rich with higher and more spaced dots on their surface whereas the valleys are Mo-poor with smaller dots that are closer to each other. These findings indicate that there is a correlation between the local metal content of the surface and the nanodot pattern properties both at the nanodot and the large corrugation scales. These results contribute to advancing the understanding of this interesting nanofabrication method and aid in developing a comprehensive theory of nanodot pattern formation and evolution.

  10. Self-organised silicide nanodot patterning by medium-energy ion beam sputtering of Si(100): local correlation between the morphology and metal content.

    PubMed

    Redondo-Cubero, A; Galiana, B; Lorenz, K; Palomares, F J; Bahena, D; Ballesteros, C; Hernandez-Calderón, I; Vázquez, L

    2016-11-04

    We have produced self-organised silicide nanodot patterns by medium-energy ion beam sputtering (IBS) of silicon targets with a simultaneous and isotropic molybdenum supply. Atomic force microscopy (AFM) studies show that these patterns are qualitatively similar to those produced thus far at low ion energies. We have determined the relevance of the ion species on the pattern ordering and properties. For the higher ordered patterns produced by Xe(+) ions, the pattern wavelength depends linearly on the ion energy. The dot nanostructures are silicide-rich as assessed by x-ray photoelectron spectroscopy (XPS) and emerge in height due to their lower sputtering yield, as observed by electron microscopy. Remarkably, a long wavelength corrugation is observed on the surface which is correlated with both the Mo content and the dot pattern properties. Thus, as assessed by electron microscopy, the protrusions are Mo-rich with higher and more spaced dots on their surface whereas the valleys are Mo-poor with smaller dots that are closer to each other. These findings indicate that there is a correlation between the local metal content of the surface and the nanodot pattern properties both at the nanodot and the large corrugation scales. These results contribute to advancing the understanding of this interesting nanofabrication method and aid in developing a comprehensive theory of nanodot pattern formation and evolution.

  11. Invited article: Digital beam-forming imaging riometer systems.

    PubMed

    Honary, Farideh; Marple, Steve R; Barratt, Keith; Chapman, Peter; Grill, Martin; Nielsen, Erling

    2011-03-01

    The design and operation of a new generation of digital imaging riometer systems developed by Lancaster University are presented. In the heart of the digital imaging riometer is a field-programmable gate array (FPGA), which is used for the digital signal processing and digital beam forming, completely replacing the analog Butler matrices which have been used in previous designs. The reconfigurable nature of the FPGA has been exploited to produce tools for remote system testing and diagnosis which have proven extremely useful for operation in remote locations such as the Arctic and Antarctic. Different FPGA programs enable different instrument configurations, including a 4 × 4 antenna filled array (producing 4 × 4 beams), an 8 × 8 antenna filled array (producing 7 × 7 beams), and a Mills cross system utilizing 63 antennas producing 556 usable beams. The concept of using a Mills cross antenna array for riometry has been successfully demonstrated for the first time. The digital beam forming has been validated by comparing the received signal power from cosmic radio sources with results predicted from the theoretical beam radiation pattern. The performances of four digital imaging riometer systems are compared against each other and a traditional imaging riometer utilizing analog Butler matrices. The comparison shows that digital imaging riometer systems, with independent receivers for each antenna, can obtain much better measurement precision for filled arrays or much higher spatial resolution for the Mills cross configuration when compared to existing imaging riometer systems.

  12. High-resolution, high-throughput, positive-tone patterning of poly(ethylene glycol) by helium beam exposure through stencil masks.

    PubMed

    Cacao, Eliedonna E; Nasrullah, Azeem; Sherlock, Tim; Kemper, Steven; Kourentzi, Katerina; Ruchhoeft, Paul; Stein, Gila E; Willson, Richard C

    2013-01-01

    In this work, a collimated helium beam was used to activate a thiol-poly(ethylene glycol) (SH-PEG) monolayer on gold to selectively capture proteins in the exposed regions. Protein patterns were formed at high throughput by exposing a stencil mask placed in proximity to the PEG-coated surface to a broad beam of helium particles, followed by incubation in a protein solution. Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR) spectra showed that SH-PEG molecules remain attached to gold after exposure to beam doses of 1.5-60 µC/cm(2) and incubation in PBS buffer for one hour, as evidenced by the presence of characteristic ether and methoxy peaks at 1120 cm(-1) and 2870 cm(-1), respectively. X-ray Photoelectron Spectroscopy (XPS) spectra showed that increasing beam doses destroy ether (C-O) bonds in PEG molecules as evidenced by the decrease in carbon C1s peak at 286.6 eV and increased alkyl (C-C) signal at 284.6 eV. XPS spectra also demonstrated protein capture on beam-exposed PEG regions through the appearance of a nitrogen N1s peak at 400 eV and carbon C1s peak at 288 eV binding energies, while the unexposed PEG areas remained protein-free. The characteristic activities of avidin and horseradish peroxidase were preserved after attachment on beam-exposed regions. Protein patterns created using a 35 µm mesh mask were visualized by localized formation of insoluble diformazan precipitates by alkaline phosphatase conversion of its substrate bromochloroindoyl phosphate-nitroblue tetrazolium (BCIP-NBT) and by avidin binding of biotinylated antibodies conjugated on 100 nm gold nanoparticles (AuNP). Patterns created using a mask with smaller 300 nm openings were detected by specific binding of 40 nm AuNP probes and by localized HRP-mediated deposition of silver nanoparticles. Corresponding BSA-passivated negative controls showed very few bound AuNP probes and little to no enzymatic formation of diformazan precipitates or silver nanoparticles.

  13. SU-D-304-05: Validation of Low-Dose-Tail Modeling for Proton Pencil Beam Spot Scanning Using a Quality Assurance Test Pattern

    SciTech Connect

    Lin, L; Huang, S; Kang, M; Solberg, T; McDonough, J; Ainsley, C

    2015-06-15

    Purpose: The purpose of this manuscript is to demonstrate the utility of a comprehensive test pattern in validating calculation models of the low-dose tails of proton pencil beam scanning (PBS) spots. Such a pattern has been used previously for quality assurance purposes to assess spot shape and location, and for determining monitor units. Methods: In this study, a scintillation detector was used to measure the test pattern in air at isocenter for two proton beam energies (115 and 225 MeV) of two IBA universal nozzles (UN). Planar measurements were compared with calculated dose distribution based on the weighted superposition of spot profiles previously measured using a pair-magnification method. Results: Including the halo component below 1% of the central dose is shown to improve the gamma-map comparison between calculation and measurement from 94.9% to 98.4% using 2 mm/2% criteria for the 115 MeV proton beam of UN #1. In contrast, including the halo component below 1% of the central dose does not improve the gamma agreement for the 115 MeV proton beam of UN #2, due to the cutoff of the halo component at off-axis locations. When location-dependent spot profiles are used for calculation instead of spot profiles at central axis, the gamma agreement is improved from 98.0% to 99.5% using 2 mm/2% criteria. The cutoff of the halo component is smaller at higher energies, and is not observable for the 225 MeV proton beam for UN #2. Conclusion: In conclusion, the use of a comprehensive test pattern can facilitate the validation of the halo component of proton PBS spots at off axis locations. The cutoff of the halo component should be taken into consideration for large fields or PBS systems that intend to trim spot profiles using apertures. This work was supported by the US Army Medical Research and Materiel Command under Contract Agreement No. DAMD17-W81XWH-07-2-0121 and W81XWH-09-2-0174.

  14. Application of E-beam hot spot inspection for early detection of systematic patterning problems to a FinFET technology

    NASA Astrophysics Data System (ADS)

    Ryan, Deborah A.; Patterson, Oliver D.; Lei, Shuen-Cheng Chris; Conklin, David; Liang, Jim; Biery, Glenn; Ogino, Atsushi; Dirahoui, Bachir; Baum, Zachary; Monkowski, Mike D.

    2015-04-01

    Early in-line detection of systematic patterning problems in technology development can dramatically improve a technology's chance for success. By uncovering layout geometries that are difficult to implement, prompt action may be taken so that solutions are in place well before product chips that contain these and similar patterns enter the manufacturing line. If a solution is not in place, this could spell disaster for the product and perhaps even the technology. Ideally, product chips will work on the first lot, which is referred to as "first time right." To help ensure this, a methodology for in-line detection of systematic patterning problems using E-beam hot spot inspection (EBHI) was developed. We review this methodology, including the latest enhancements. Pattern simulation tools and other sources are used to provide die locations with challenging geometries for evaluation. EBHI evaluates the patterning capability for these locations using modulated wafers. A multifunction team addresses any hot spots that fail within the process window. EBHI is then used to evaluate the solutions proposed by this team. Application of this methodology to a fin-shaped field effect transistor technology is described using examples from the fin and back end of line modules. These examples illustrate the full range of actions used to resolve patterning issues.

  15. Investigation of fabrication process for sub 20-nm dense pattern of non-chemically amplified electron beam resist based on acrylic polymers

    NASA Astrophysics Data System (ADS)

    Ochiai, Shunsuke; Takayama, Tomohiro; Kishimura, Yukiko; Asada, Hironori; Sonoda, Manae; Iwakuma, Minako; Hoshino, Ryoichi

    2016-10-01

    In this study, we examine exposure characteristics of a positive tone electron beam resist consisting of methyl α- chloroacrylate and α-methylstyrene by changing the development process conditions. 25/25 nm and 30/30 nm line-andspace (L/S) patterns (design value) are developed in amyl and heptyl acetates. The resist patterns developed at 0ºC for 120 s show the better shapes having the vertical sidewalls than those developed at 22 °C for 60 s. The dose margins of pattern formation for 0°C development become wider, although the sensitivities are lower. The effect of post exposure baking (PEB) on exposure characteristics is also investigated. Adding PEB process performed at 120°C for 2 min, the dose margin also becomes wider although the sensitivity is lower. 20/20 nm L/S patterns are fabricated by using PEB and/or 0°C development. Though the required exposure dose is larger, the resist pattern is improved by PEB and/or 0°C development. The formation of 35 nm pitch pattern is also presented.

  16. Diffraction pattern by nanometric thin films under illumination of an orbital angular momentum beam with integer topological charge

    NASA Astrophysics Data System (ADS)

    Mendoza, J. H.; Díaz, C. F.; Acevedo, C. H.; Torres, Y.

    2016-02-01

    The orbital angular momentum of light has a big contribution in many engineering applications like optical communications, because this physical property allows eigenstates characteristic of the wavefront rotation when the beam is propagated. The nature of these eigenstates allows that information can be encoded and gives immunity to electromagnetic interference, allowing an increase of bandwidth, cadence and capacity of the communication channel. This work shown the methodology using nanometric thin films like Titanium based (TiO2) grown over strontium titanate (SrTiO3) support, to distinguish and discriminate a well- defined integer value of the topological charge of an OAM beam.

  17. Small phase pattern 2D beam steering and a single LCOS design of 40 1 × 12 stacked wavelength selective switches.

    PubMed

    Yang, Haining; Robertson, Brian; Wilkinson, Peter; Chu, Daping

    2016-05-30

    Two-dimensional beam steering by small, square, phase patterns as small as 50 × 50 pixels on a phase-only liquid crystal on silicon (LCOS) device is experimentally verified as suitable for the application of wavelength selective switches (WSSs), in terms of the diffraction efficiency and steering accuracy. This enables a proposed highly functional and versatile stacked switch architecture, where 40 independent 1 × 12 WSSs can be realised on a single 4k LCOS device. They can be configured to support a 1 × N WSSs with N≤144, or an N × N wavelength crossconnect with N≤12.

  18. Evaluation of opening pattern and bone neoformation at median palatal suture area in patients submitted to surgically assisted rapid maxillary expansion (SARME) through cone beam computed tomography

    PubMed Central

    SALGUEIRO, Daniel Gomes; RODRIGUES, Vitor Hugo Leite de Oliveira; TIEGHI, Victor; de MENEZES, Carolina Carmo; GONÇALES, Eduardo Sanches; FERREIRA, Osny

    2015-01-01

    Surgically assisted rapid maxillary expansion (SARME) is the treatment of choice to adult patients even with severe transversal maxillary discrepancies. However, the adequate retention period to achieve the bone remodeling, thus assuring treatment stability, is controversial. Objective To evaluate the opening pattern and bone neoformation process at the midpalatal suture in patients submitted to surgically assisted (SARME) through cone beam computed tomography (CBCT). Material and Methods Fourteen patients were submitted to SARME through subtotal Le Fort I osteotomy. Both the opening pattern and the mean bone density at midpalatal suture area to evaluate bone formation were assessed pre- and post-operatively (15, 60 and 180 days) through CBCT. Results Type I opening pattern (from anterior to posterior nasal spine) occurred in 12 subjects while type II opening pattern (from anterior nasal spine to transverse palatine suture) occurred in 2 individuals. The 180-day postoperative mean (PO 180) of bone density value was 49.9% of the preoperative mean (Pre) value. Conclusions The opening pattern of midpalatal suture is more related to patients’ age (23.9 years in type I and 33.5 years in type II) and surgical technique. It was not possible to observe complete bone formation at midpalatal suture area at the ending of the retention period studied (180 days). PMID:26398512

  19. Theoretical study on effects of photodecomposable quenchers in line-and-space pattern fabrication with 7 nm quarter-pitch using chemically amplified electron beam resist process

    NASA Astrophysics Data System (ADS)

    Kozawa, Takahiro

    2017-04-01

    The line width roughness (LWR) is a significant issue in the development of chemically amplified resists. The increase in sensitizer concentration is inevitable for the suppression of LWR in the sub-10 nm fabrication. In this study, we investigated the effects of photodecomposable quenchers from the viewpoint of the excluded volume effect, assuming line-and-space patterns with 7 nm quarter-pitch (7 nm space width and 28 nm pitch). The pattern formation of chemically amplified electron beam resists with photodecomposable quenchers was calculated and compared with those with conventional quenchers. It was found that the sum of the concentrations of acid generators and quenchers (photodecomposable or conventional quenchers) can be reduced without decreasing the chemical gradient (an indicator of LWR) by using the photodecomposable quenchers. The photodecomposable quenchers are considered essential in the high-resolution fabrication.

  20. Patterned growth of InGaN/GaN quantum wells on freestanding GaN grating by molecular beam epitaxy.

    PubMed

    Wang, Yongjin; Hu, Fangren; Hane, Kazuhiro

    2011-02-04

    We report here the epitaxial growth of InGaN/GaN quantum wells on freestanding GaN gratings by molecular beam epitaxy (MBE). Various GaN gratings are defined by electron beam lithography and realized on GaN-on-silicon substrate by fast atom beam etching. Silicon substrate beneath GaN grating region is removed from the backside to form freestanding GaN gratings, and the patterned growth is subsequently performed on the prepared GaN template by MBE. The selective growth takes place with the assistance of nanoscale GaN gratings and depends on the grating period P and the grating width W. Importantly, coalescences between two side facets are realized to generate epitaxial gratings with triangular section. Thin epitaxial gratings produce the promising photoluminescence performance. This work provides a feasible way for further GaN-based integrated optics devices by a combination of GaN micromachining and epitaxial growth on a GaN-on-silicon substrate.PACS81.05.Ea; 81.65.Cf; 81.15.Hi.

  1. Filling a Conical Cavity

    NASA Astrophysics Data System (ADS)

    Nye, Kyle; Eslam-Panah, Azar

    2016-11-01

    Root canal treatment involves the removal of infected tissue inside the tooth's canal system and filling the space with a dense sealing agent to prevent further infection. A good root canal treatment happens when the canals are filled homogeneously and tightly down to the root apex. Such a tooth is able to provide valuable service for an entire lifetime. However, there are some examples of poorly performed root canals where the anterior and posterior routes are not filled completely. Small packets of air can be trapped in narrow access cavities when restoring with resin composites. Such teeth can cause trouble even after many years and lead the conditions like acute bone infection or abscesses. In this study, the filling of dead-end conical cavities with various liquids is reported. The first case studies included conical cavity models with different angles and lengths to visualize the filling process. In this investigation, the rate and completeness at which a variety of liquids fill the cavity were observed to find ideal conditions for the process. Then, a 3D printed model of the scaled representation of a molar with prepared post spaces was used to simulate the root canal treatment. The results of this study can be used to gain a better understanding of the restoration for endodontically treated teeth.

  2. Pattern transfer from the e-beam resist, over the nanoimprint resist and to the final silicon substrate

    NASA Astrophysics Data System (ADS)

    He, Jian; Howitz, S.; Richter, K.; Bartha, J. W.; Moench, J. I.

    2012-03-01

    We developed Fluor-based RIE processes to fabricate nanoimprint template in silicon and to transfer patterns from the imprint resist to the silicon substrate. The etched silicon patterns have slightly tapered and smooth sidewalls. The sidewall angle can be controlled between 85° and 90° by varying the ratio of the used gas. The dimension of the etched structures is identical with the patterns in the resist. We demonstrated line structures in silicon substrate down to 50 nm. The etching rate is over 100 nm per minute and the maximal achieved aspect ratio is more than 10.

  3. Self-catalyzed ternary core-shell GaAsP nanowire arrays grown on patterned Si substrates by molecular beam epitaxy.

    PubMed

    Zhang, Yunyan; Wu, Jiang; Aagesen, Martin; Holm, Jeppe; Hatch, Sabina; Tang, Mingchu; Huo, Suguo; Liu, Huiyun

    2014-08-13

    The growth of self-catalyzed ternary core-shell GaAsP nanowire (NW) arrays on SiO2 patterned Si(111) substrates has been demonstrated by using solid-source molecular beam epitaxy. A high-temperature deoxidization step up to ∼ 900 °C prior to NW growth was used to remove the native oxide and/or SiO2 residue from the patterned holes. To initiate the growth of GaAsP NW arrays, the Ga predeposition used for assisting the formation of Ga droplets in the patterned holes, was shown to be another essential step. The effects of the patterned-hole size on the NW morphology were also studied and explained using a simple growth model. A lattice-matched radial GaAsP core-shell NW structure has subsequently been developed with room-temperature photoluminescence emission around 740 nm. These results open up new perspectives for integrating position-controlled III-V NW photonic and electronic structures on a Si platform.

  4. Cone-beam computed tomography based evaluation of rotational patterns of dentofacial structures in skeletal Class III deformity with mandibular asymmetry

    PubMed Central

    Ryu, Hyeong-Seok; An, Ki-Yong

    2015-01-01

    Objective The purpose of this study was to assess rotational patterns of dentofacial structures according to different vertical skeletal patterns by cone-beam computed tomography (CBCT) and analyze their influence on menton deviation in skeletal Class III deformity with mandibular asymmetry. Methods The control group consisted of 30 young adults (15 men, 15 women) without any severe skeletal deformity. The asymmetry group included 55 adults (28 men, 27 women) with skeletal Class III deformity and at least 3-mm menton deviation from the midsagittal plane; it was divided into the hyperdivergent and hypodivergent subgroups using a mandibular plane angle cutoff of 35°. Fourteen rotational variables of the dental arches and mandible were measured and compared among the groups. Correlations between menton deviation and the other variables were evaluated. Results The asymmetry group showed significantly larger measurements of roll and yaw in the mandible than the control group. The hypodivergent subgroup showed significant differences in maxillary posterior measurements of yaw (p < 0.01) and maxillary anterior shift (p < 0.05) compared with the hyperdivergent subgroup. All the mandibular measurements had significant correlations with menton deviation (p < 0.01). Most measurements of roll were positively correlated with one another (p < 0.01). Measurements of yaw and roll in the posterior regions were also positively correlated (p < 0.05). Conclusions Menton deviation in skeletal Class III deformity with mandibular asymmetry is influenced by rotation of mandibular posterior dentofacial structures. The rotational patterns vary slightly according to the vertical skeletal pattern. PMID:26258061

  5. Filled Landau levels in neutral quantum gases

    SciTech Connect

    Oehberg, P.; Juzeliunas, G.; Ruseckas, J.; Fleischhauer, M.

    2005-11-15

    We consider the signatures of the integer quantum Hall effect in a degenerate gas of electrically neutral atomic fermions. An effective magnetic field is achieved by applying two incident light beams with a high orbital angular momentum. We show how states corresponding to completely filled Landau levels are obtained and discuss various possibilities to measure the incompressible nature of the trapped two-dimensional gas.

  6. Comparison of interradicular distances and cortical bone thickness in Thai patients with Class I and Class II skeletal patterns using cone-beam computed tomography

    PubMed Central

    Khumsarn, Nattida; Patanaporn, Virush; Jotikasthira, Dhirawat

    2016-01-01

    Purpose This study evaluated and compared interradicular distances and cortical bone thickness in Thai patients with Class I and Class II skeletal patterns, using cone-beam computed tomography (CBCT). Materials and Methods Pretreatment CBCT images of 24 Thai orthodontic patients with Class I and Class II skeletal patterns were included in the study. Three measurements were chosen for investigation: the mesiodistal distance between the roots, the width of the buccolingual alveolar process, and buccal cortical bone thickness. All distances were recorded at five different levels from the cementoenamel junction (CEJ). Descriptive statistical analysis and t-tests were performed, with the significance level for all tests set at p<0.05. Results Patients with a Class II skeletal pattern showed significantly greater maxillary mesiodistal distances (between the first and second premolars) and widths of the buccolingual alveolar process (between the first and second molars) than Class I skeletal pattern patients at 10 mm above the CEJ. The maxillary buccal cortical bone thicknesses between the second premolar and first molar at 8 mm above the CEJ in Class II patients were likewise significantly greater than in Class I patients. Patients with a Class I skeletal pattern showed significantly wider mandibular buccolingual alveolar processes than did Class II patients (between the first and second molars) at 4, 6, and 8 mm below the CEJ. Conclusion In both the maxilla and mandible, the mesiodistal distances, the width of the buccolingual alveolar process, and buccal cortical bone thickness tended to increase from the CEJ to the apex in both Class I and Class II skeletal patterns. PMID:27358819

  7. Antenna Beam Coverage Concepts

    NASA Technical Reports Server (NTRS)

    Estabrook, Polly; Motamedi, Masoud

    1990-01-01

    The strawman Personal Access Satellite System (PASS) design calls for the use of a CONUS beam for transmission between the supplier and the satellite and for fixed beams for transmission between the basic personal terminal and the satellite. The satellite uses a 3 m main reflector for transmission at 20 GHz and a 2 m main reflector for reception at 30 GHz. There are several types of spot beams under consideration for the PASS system besides fixed beams. The beam pattern of a CONUS coverage switched beam is shown along with that of a scanning beam. A switched beam refers to one in which the signal from the satellite is connected alternatively to various feed horns. Scanning beams are taken to mean beams whose footprints are moved between contiguous regions in the beam's coverage area. The advantages and disadvantages of switched and/or scanning beams relative to fixed beams. The consequences of using switched/scanning in lieu of fixed beams in the PASS design and attempts are made to evaluate the listed advantages and disadvantages. Two uses of switched/scanning beams are examined. To illustrate the implications of switched beams use on PASS system design, operation at two beam scan rates is explored.

  8. Dual beam optical interferometer

    NASA Technical Reports Server (NTRS)

    Gutierrez, Roman C. (Inventor)

    2003-01-01

    A dual beam interferometer device is disclosed that enables moving an optics module in a direction, which changes the path lengths of two beams of light. The two beams reflect off a surface of an object and generate different speckle patterns detected by an element, such as a camera. The camera detects a characteristic of the surface.

  9. Influence of template fill in graphoepitaxy directed self-assembly

    NASA Astrophysics Data System (ADS)

    Doise, Jan; Bekaert, Joost; Chan, Boon Teik; Hong, SungEun; Lin, Guanyang; Gronheid, Roel

    2016-07-01

    Directed self-assembly (DSA) of block copolymers (BCP) is considered a promising patterning approach for the 7-nm node and beyond. Specifically, a graphoepitaxy process using a cylindrical phase BCP may offer an efficient solution for patterning randomly distributed contact holes with subresolution pitches, such as found in via and cut mask levels. In any graphoepitaxy process, the pattern density impacts the template fill (local BCP thickness inside the template) and may cause defects due to over- or underfilling of the template. In order to tackle this issue thoroughly, the parameters that determine template fill and the influence of template fill on the resulting pattern should be investigated. Using three process flow variations (with different template surface energy), template fill is experimentally characterized as a function of pattern density and film thickness. The impact of these parameters on template fill is highly dependent on the process flow, and thus prepattern surface energy. Template fill has a considerable effect on the pattern transfer of the DSA contact holes into the underlying layer. Higher fill levels give rise to smaller contact holes and worse critical dimension uniformity. These results are important for DSA-aware design and show that fill is a crucial parameter in graphoepitaxy DSA.

  10. Loose-fill insulations

    SciTech Connect

    1995-05-01

    Whether you are increasing the insulation levels in your current home or selecting insulation for a new home, choosing the right insulation material can be challenging. Fibrous loose-fill insulations such as cellulose, fiberglass, and rock wool are options you may wish to consider. This publication will introduce you to these materials--what they are, how they are applied, how they compare with each other, and other considerations regarding their use--so that you can decide whether loose fills are right for your home.

  11. Junction size dependence of ferroelectric properties in e-beam patterned BaTiO{sub 3} ferroelectric tunnel junctions

    SciTech Connect

    Singh, A. V.; Gupta, A.; Althammer, M.; Rott, K.; Reiss, G.

    2015-09-21

    We investigate the switching characteristics in BaTiO{sub 3}-based ferroelectric tunnel junctions patterned in a capacitive geometry with circular Ru top electrode with diameters ranging from ∼430 to 2300 nm. Two different patterning schemes, viz., lift-off and ion-milling, have been employed to examine the variations in the ferroelectric polarization, switching, and tunnel electro-resistance resulting from differences in the pattering processes. The values of polarization switching field are measured and compared for junctions of different diameter in the samples fabricated using both patterning schemes. We do not find any specific dependence of polarization switching bias on the size of junctions in both sample stacks. The junctions in the ion-milled sample show up to three orders of resistance change by polarization switching and the polarization retention is found to improve with increasing junction diameter. However, similar switching is absent in the lift-off sample, highlighting the effect of patterning scheme on the polarization retention.

  12. Ab-initio primitive cell parameters from single convergent-beam electron diffraction patterns: a converse route to the identification of microcrystals with electrons.

    PubMed

    Le Page, Y

    1992-04-01

    A new method for the ab initio derivation of Buerger-reduced primitive cell parameters from coordinate measurements of spots on single convergent-beam electron diffraction (CBED) patterns is described, which does not involve trial-and-error. The pattern can be taken along any zone axis, and misorientations of the crystallite by as much as a few degrees are taken into account without loss of accuracy. This derivation of cell parameters by least-squares analysis of the measurements has been automated in a program called NRCBED. Present accuracy is about 1% on lengths and 2 degrees on angles, but could be significantly improved by modelling projector lens aberrations, or by using a microscope without a projector lens. With present technology, it is possible to obtain a CBED pattern and a semi-quantitative energy-dispersive X-ray (EDX) analysis simultaneously from a single microcrystal a few hundred Angströms across. It becomes therefore possible to identify the material of the crystal on a single CBED pattern: a cell parameter database for known compounds is searched with the primitive cell parameters obtained in the above way, and with a mask describing the EDX results qualitatively. Feasibility is demonstrated on a crystallite of CeO2 500 Angströms across. With this new approach, trial-and-error should disappear from the solution of other long-standing problems: interpretation of X-ray powder patterns for new compounds in the presence of impurity lines, or in the case of multiple phases should become straight-forward.

  13. Theoretical study of fabrication of line-and-space patterns with 7 nm quarter-pitch using electron beam lithography with chemically amplified resist processes: II. Stochastic effects

    NASA Astrophysics Data System (ADS)

    Kozawa, Takahiro

    2015-09-01

    Electron beam (EB) lithography is a core technology for nanofabrication. Owing to the increasing demand for high-resolution semiconductor lithography, the requirements for the resist processes of EB lithography for the photomasks used in ArF immersion and extreme ultraviolet lithographies and the mold fabrication of nanoimprints have also become stricter. In this study, the feasibility of single nano patterning by EB lithography with a chemically amplified resist process was investigated from the viewpoint of stochastic effects. The latent images of line-and-space patterns with a 7 nm quarter-pitch (7 nm space width and 21 nm line width) were calculated using a Monte Carlo method on the basis of the sensitization and reaction mechanisms of chemically amplified EB resists. Compared with the line-and-space pattern with a 7 nm half-pitch, line edge roughness (LER) and the stochastic pinching generation are considered to be significantly improved by increasing the pitch. It was found that the suppression of the stochastic generation of bridges is the critical issue in 7 nm quarter-pitch fabrication.

  14. Three-dimensional analysis of dental decompensation for skeletal Class III malocclusion on the basis of vertical skeletal patterns obtained using cone-beam computed tomography

    PubMed Central

    Kim, Yong-Il; Choi, Youn-Kyung; Son, Woo-Sung; Kim, Seong-Sik

    2012-01-01

    Objective To evaluate the presurgical orthodontic tooth movement of mandibular teeth after dental decompensation for skeletal Class III deformities on the basis of vertical skeletal patterns. Methods This cohort was comprised of 62 patients who received presurgical orthodontic treatment. These patients were divided into 3 groups according to their vertical skeletal patterns. Changes in the positions of the mandibular central incisor, canine, premolar, and 1st molar after presurgical orthodontic treatment were measured using a cone-beam computed tomography (CBCT) superimposition method. Results The incisors moved forward after dental decompensation in all 3 groups. The canines in group I and the 1st premolars in groups I and III also moved forward. The incisors and canines were extruded in groups I and II. The 1st and 2nd premolars were also extruded in all groups. Vertical changes in the 1st premolars differed significantly between the groups. We also observed lateral movement of the canines in group III and of the 1st premolar, 2nd premolar, and 1st molar in all 3 groups (p < 0.05). Conclusions Movement of the mandibular incisors and premolars resolved the dental compensation. The skeletal facial pattern did not affect the dental decompensation, except in the case of vertical changes of the 1st premolars. PMID:23173115

  15. Beam patterns in an optical parametric oscillator set-up employing walk-off compensating beta barium borate crystals

    NASA Astrophysics Data System (ADS)

    Kaucikas, M.; Warren, M.; Michailovas, A.; Antanavicius, R.; van Thor, J. J.

    2013-02-01

    This paper describes the investigation of an optical parametric oscillator (OPO) set-up based on two beta barium borate (BBO) crystals, where the interplay between the crystal orientations, cut angles and air dispersion substantially influenced the OPO performance, and especially the angular spectrum of the output beam. Theory suggests that if two BBO crystals are used in this type of design, they should be of different cuts. This paper aims to provide an experimental manifestation of this fact. Furthermore, it has been shown that air dispersion produces similar effects and should be taken into account. An x-ray crystallographic indexing of the crystals was performed as an independent test of the above conclusions.

  16. Nanogram calorimetry using microscale suspended SiN{sub x} platforms fabricated via focused ion beam patterning

    SciTech Connect

    Wickey, K. J.; Chilcote, M.; Johnston-Halperin, E.

    2015-01-15

    Comprehensive characterization of thermal properties in nanoscale heterostructures requires microscale thermally isolated platforms combined with sensitive thermometry in order to measure small heat accumulations. Amorphous SiN{sub x} membranes are often used for these measurements due to their low thermal conductivity and compatibility with standard fabrication techniques. The total thermal conductance of such SiN{sub x} membranes is typically microwatts per kelvin or higher. Here, we further reduce this thermal coupling to 120 nW/K by using a focused ion beam (FIB) to remove large portions of commercially available amorphous SiN{sub x} membranes, leaving a 100 μm × 100 μm square platform suspended by 10 μm wide by 325 μm long support legs. We demonstrate the capability of these platforms by measuring the heat capacity of a 6.2 ng Au sample and show that it matches well with established specific heat of bulk Au.

  17. Algorithm of Shaping Multiple-beam Braggs Acousto-optic Diffraction Laser Field Into 1D and 2D Patterns

    NASA Astrophysics Data System (ADS)

    Zakharchenko, S.; Baturin, A.

    2015-09-01

    Algorithm of solving a direct problem of acousto-optic interaction between laser emission and acoustic signal consisting of a set of equidistant frequency components is proposed. An infinite system of coupled wave differential equations is reduced to eigenvalue problem. The contribution of the higher rediffraction orders is analyzed separately. Inverse problem of finding an optimal set of equidistant frequency components of a driving acoustic signal to form the objective diffraction pattern is also considered and a few optimization approaches are analyzed. A naïve heuristic method of splitting 2D pattern into subframes, each suitable for simultaneous projection by two acousto-optical deflectors driven by multifrequency composite signal, is developed.

  18. Direct fabrication of nanoscale bio-adhesive patterns by electron beam surface modification of plasma polymerized poly ethylene oxide-like coatings

    NASA Astrophysics Data System (ADS)

    Brétagnol, Frédéric; Sirghi, Lucel; Mornet, Stéphane; Sasaki, Takao; Gilliland, Douglas; Colpo, Pascal; Rossi, Francois

    2008-03-01

    In this study we present a method to produce nanostructured surfaces containing bio-adhesive features inside a non bio-adhesive matrix. The strategy is based on the combination of low pressure plasma polymerization and electron beam lithography processes and allows the fabrication of the structured materials in just two steps without using any solvents. In a first step, a thin protein-and-cell-repelling coating (~10 nm) is obtained by plasma polymerization of Di-glyme. Then, in a second step, the bio-adhesive properties of the layer are tuned by monitoring the concentration of ether bonds of the film by irradiating it locally by different irradiation doses with an electron beam. Time-of-flight secondary ion mass spectroscopy and atomic force microscopy analysis have been used to characterize the produced surfaces. Experiments with a model protein (bovine serum albumin) on the patterned surfaces show preferential adhesion to the irradiated regions, indicating the potential of this simple technique for the development of highly compacted sensitive bio-sensing devices.

  19. E × B flow velocity deduced from the poloidal motion of fluctuation patterns in neutral beam injected L-mode plasmas on KSTAR

    NASA Astrophysics Data System (ADS)

    Lee, W.; Leem, J.; Yun, G. S.; Park, H. K.; Ko, S. H.; Choi, M. J.; Wang, W. X.; Budny, R. V.; Ethier, S.; Park, Y. S.; Luhmann, N. C.; Domier, C. W.; Lee, K. D.; Ko, W. H.; Kim, K. W.

    2016-05-01

    A method for direct assessment of the equilibrium E × B flow velocity ( E ×B flow shear is responsible for the turbulence suppression and transport reduction in tokamak plasmas) is investigated based on two facts. The first one is that the apparent poloidal rotation speed of density fluctuation patterns is close to the turbulence rotation speed in the direction perpendicular to the local magnetic field line within the flux surface. And the second "well-known" fact is that the turbulence rotation velocity consists of the equilibrium E × B flow velocity and intrinsic phase velocity of turbulence in the E × B flow frame. In the core region of the low confinement (L-mode) discharges where a strong toroidal rotation is induced by neutral beam injection, the apparent poloidal velocities (and turbulence rotation velocities) are good approximations of the E ×B flow velocities since linear gyrokinetic simulations suggest that the intrinsic phase velocity of the dominant turbulence is significantly lower than the apparent poloidal velocity. In the neutral beam injected L-mode plasmas, temporal and spatial scales of the measured turbulence are studied by comparing with the local equilibrium parameters relevant to the ion-scale turbulence.

  20. Three-dimensional cone-beam computed tomography based comparison of condylar position and morphology according to the vertical skeletal pattern

    PubMed Central

    Park, In-Young; Kim, Ji-Hyun

    2015-01-01

    Objective To compare condylar position and morphology among different vertical skeletal patterns. Methods Diagnostic cone-beam computed tomography images of 60 adult patients (120 temporomandibular joints) who visited the orthodontic clinic of Hallym University Sacred Heart Hospital were reviewed. The subjects were divided into three equal groups according to the mandibular plane angle: hypodivergent, normodivergent, and hyperdivergent groups. Morphology of the condyle and mandibular fossa and condylar position were compared among the groups. Results The hypodivergent and hyperdivergent groups showed significant differences in superior joint spaces, antero-posterior condyle width, medio-lateral condyle width, condyle head angle, and condylar shapes. Conclusions Condylar position and morphology vary according to vertical facial morphology. This relationship should be considered for predicting and establishing a proper treatment plan for temporomandibular diseases during orthodontic treatment. PMID:25798412

  1. Study of growth properties of InAs islands on patterned InP substrates defined by focused ion beam

    NASA Astrophysics Data System (ADS)

    Ribeiro-Andrade, R.; Malachias, A.; Miquita, D. R.; Vasconcelos, T. L.; Kawabata, R.; Pires, M. P.; Souza, P. L.; Rodrigues, W. N.

    2017-03-01

    This work describes morphological and crystalline properties of the InAs islands grown on templates created by focused ion beam (FIB) on indium phosphide (InP) substrates. Regular arrangements of shallow holes are created on the InP (001) surfaces, acting as preferential nucleation sites for InAs islands grown by Metal-Organic Vapor Phase Epitaxy. Ion doses ranging from 1015 to 1016 Ga+/cm2 were used and islands were grown for two sub-monolayer coverages. We observe the formation of clusters in the inner surfaces of the FIB produced cavities and show that for low doses templates the nanostructures are mainly coherent while templates created with large ion doses lead to the growth of incoherent islands with larger island density. The modified island growth is described by a simple model based on the surface potential and the net adatom flow to the cavities. We observe that obtained morphologies result from a competition between coarsening and coalescence mechanisms.

  2. Shape transitions and island nucleation for Si/Ge molecular beam epitaxy on stripe-patterned Si (001) substrate

    SciTech Connect

    Sanduijav, B.; Chen, G.; Springholz, G.; Matei, D.

    2009-09-15

    Si and Ge growth on the stripe patterned Si (001) substrates is studied using scanning tunneling microscopy. During Si buffer growth, the stripe morphology rapidly evolves from multifaceted ''U'' to ''V''-shaped forms. This involves successive transitions between different low energy (11n) side facets, where n continuously decreases from n=3 to 20. Ge growth on such stripes induces the formation of a pronounced side wall ripple structure when the Ge thickness exceeds three monolayers. This ripple structure consists of alternating (105) microfacets oriented perpendicularly to the stripes. Depending of the side wall geometry, Ge nanoislands subsequently nucleate either on the side walls or at the bottom of grooves. The latter only occurs for ''V''-shaped stripes, where the side wall ripples extend all the way from the top to the bottom of the grooves, allowing efficient downward mass transport. For multifaceted ''U'' stripes, the side wall ripples are interrupted by steeper side wall segments such that mounds and subsequently, pyramids and domes grow on the side walls instead of at the bottom of the grooves. The island shapes strongly depend on their position on the pattern topography, which also affects the critical coverage for island nucleation as well as for the transition from pyramids to domes. The mechanisms for nucleation at different positions are clarified by detailed analysis and the role of kinetic as well as energetic factors identified.

  3. Gas filled panel insulation

    DOEpatents

    Griffith, B.T.; Arasteh, D.K.; Selkowitz, S.E.

    1993-12-14

    A structural or flexible highly insulative panel which may be translucent, is formed from multi-layer polymeric material in the form of an envelope surrounding a baffle. The baffle is designed so as to minimize heat transfer across the panel, by using material which forms substantially closed spaces to suppress convection of the low conductivity gas fill. At least a portion of the baffle carries a low emissivity surface for suppression of infrared radiation. 18 figures.

  4. Gas filled panel insulation

    DOEpatents

    Griffith, Brent T.; Arasteh, Dariush K.; Selkowitz, Stephen E.

    1993-01-01

    A structural or flexible highly insulative panel which may be translucent, is formed from multi-layer polymeric material in the form of an envelope surrounding a baffle. The baffle is designed so as to minimize heat transfer across the panel, by using material which forms substantially closed spaces to suppress convection of the low conductivity gas fill. At least a portion of the baffle carries a low emissivity surface for suppression of infrared radiation.

  5. Hierarchical multiple bit clusters and patterned media enabled by novel nanofabrication techniques -- High resolution electron beam lithography and block polymer self assembly

    NASA Astrophysics Data System (ADS)

    Xiao, Qijun

    This thesis discusses the full scope of a project exploring the physics of hierarchical clusters of interacting nanomagnets. These clusters may be relevant for novel applications such as multilevel data storage devices. The work can be grouped into three main activities: micromagnetic simulation, fabrication and characterization of proof-of-concept prototype devices, and efforts to scale down the structures by creating the hierarchical structures with the aid of diblock copolymer self assembly. Theoretical micromagnetic studies and simulations based on Landau-Lifshitz-Gilbert (LLG) equation were conducted on nanoscale single domain magnetic entities. For the simulated nanomagnet clusters with perpendicular uniaxial anisotropy, the simulation showed the switching field distributions, the stability of the magnetostatic states with distinctive total cluster perpendicular moments, and the stepwise magnetic switching curves. For simulated nanomagnet clusters with in-plane shape anisotropy, the simulation showed the stepwise switching behaviors governed by thermal agitation and cluster configurations. Proof-of-concept cluster devices with three interacting Co nanomagnets were fabricated by e-beam lithography (EBL) and pulse-reverse electrochemical deposition (PRECD). EBL patterning on a suspended 100 nm SiN membrane showed improved lateral lithography resolution to 30 nm. The Co nanomagnets deposited using the PRECD method showed perpendicular anisotropy. The switching experiments with external applied fields were able to switch the Co nanomagnets through the four magnetostatic states with distinctive total perpendicular cluster magnetization, and proved the feasibility of multilevel data storage devices based on the cluster concept. Shrinking the structures size was experimented by the aid of diblock copolymer. Thick poly(styrene)-b-poly(methyl methacrylate) (PS-b-PMMA) diblock copolymer templates aligned with external electrical field were used to fabricate long Ni

  6. Diversions: Hilbert and Sierpinski Space-Filling Curves, and beyond

    ERIC Educational Resources Information Center

    Gough, John

    2012-01-01

    Space-filling curves are related to fractals, in that they have self-similar patterns. Such space-filling curves were originally developed as conceptual mathematical "monsters", counter-examples to Weierstrassian and Reimannian treatments of calculus and continuity. These were curves that were everywhere-connected but…

  7. Anisotropy of selective epitaxy in nanoscale-patterned growth: GaAs nanowires selectively grown on a SiO2-patterned (001) substrate by molecular-beam epitaxy

    NASA Astrophysics Data System (ADS)

    Lee, S. C.; Dawson, L. R.; Brueck, S. R. J.; Jiang, Y.-B.

    2005-12-01

    Anisotropic selective epitaxy in nanoscale-patterned growth (NPG) by molecular-beam epitaxy is investigated on a 355nm period two-dimensional array of circular holes fabricated in a 30-nm-thick SiO2 film on a GaAs(001) substrate. The hole diameter ranged from 70to150nm. The small hole diameter and the very thin masking layer stimulated lateral growth over the SiO2 surface at an early stage of selective epitaxy on this patterned substrate. Lateral overgrowth associated with selective epitaxy, however, did not proceed isotropically along the circular boundary between the open substrate surface and the SiO2 mask. There was preferential growth direction parallel to ⟨111⟩B. This anisotropy in the selective epitaxy resulted in the formation of a nanoscale, nontapered, straight-wire-type epitaxial layer (GaAs nanowires), which had a length of up to 1.8μm for a nominal 200nm deposition. Every GaAs nanowire had a hexagonal prismatic shape directed along ⟨111⟩B and was surrounded by six (110) sidewalls. The anisotropy of selective epitaxy and faceting in NPG were affected by the profile of the SiO2 mask and are interpreted using a minimization of the total surface energy for equilibrium crystal shape.

  8. Beam Purification by Photodetachment

    SciTech Connect

    Liu, Yuan; Beene, James R; Havener, Charles C; Galindo-Uribarri, Alfredo {nmn}; Andersson, P.; Lindahl, A. O.; Hanstorp, D.; Forstner, Dr. Oliver; Gottwald, T.; Wendt, K.

    2012-01-01

    Ion beam purity is of crucial importance to many basic and applied studies. Selective photodetachment has been proposed to suppress unwanted species in negative ion beams while preserving the intensity of the species of interest. A highly efficient technique based on photodetachment in a gas-filled radio frequency quadrupole ion cooler has been demonstrated. In off-line experiments with stable ions, up to 104 times suppression of the isobar contaminants in a number of interesting radioactive negative ion beams has been demonstrated. For selected species, this technique promises experimental possibilities in studies on exotic nuclei, accelerator mass spectrometry, and fundamental properties of negative atomic and molecular ions.

  9. Dye filled security seal

    DOEpatents

    Wilson, Dennis C. W.

    1982-04-27

    A security seal for providing an indication of unauthorized access to a sealed object includes an elongate member to be entwined in the object such that access is denied unless the member is removed. The elongate member has a hollow, pressurizable chamber extending throughout its length that is filled with a permanent dye under greater than atmospheric pressure. Attempts to cut the member and weld it together are revealed when dye flows through a rupture in the chamber wall and stains the outside surface of the member.

  10. Fluid Dynamics of Bottle Filling

    NASA Astrophysics Data System (ADS)

    McGough, Patrick; Gao, Haijing; Appathurai, Santosh; Basaran, Osman

    2011-11-01

    Filling of bottles is a widely practiced operation in a large number of industries. Well known examples include filling of ``large'' bottles with shampoos and cleaners in the household products and beauty care industries and filling of ``small'' bottles in the pharmaceutical industry. Some bottle filling operations have recently drawn much attention from the fluid mechanics community because of the occurrence of a multitude of complex flow regimes, transitions, and instabilities such as mounding and coiling that occur as a bottle is filled with a fluid. In this talk, we present a primarily computational study of the fluid dynamical challenges that can arise during the rapid filling of bottles. Given the diversity of fluids used in filling applications, we consider four representative classes of fluids that exhibit Newtonian, shear-thinning, viscoelastic, and yield-stress rheologies. The equations governing the dynamics of bottle filling are solved either in their full 3D but axisymmetric form or using the slender-jet approximation.

  11. Uniformly Rastering an Electron Beam on a Polarized Cryotarget

    NASA Astrophysics Data System (ADS)

    Brakman, David; Gilfoyle, Gerard; Cuevas, Chris

    2016-09-01

    The HDice experiment in Hall B of Jefferson Lab will measure excited nucleon states more completely by controlling the spin states of a hydrogen target. For the experiment, an electron beam will be incident on a polarized target of frozen hydrogen-deuteride, and the debris produced will be measured by the CEBAF Large Acceptance Spectrometer. To ensure that sections of the target don't overheat and depolarize, it is necessary to quickly and uniformly move the beam across the circular surface of the target entrance window. This process of distributing a sequence of beam packets over the x-y plane is known as rastering and is accomplished with a pair of electromagnets that deflect the beam along the x and y axes. We mathematically defined a parametric spiral pattern over the surface of the target window. As sine and cosine waves for x(t) and y(t) produce a circular x-y pattern, we scale their amplitudes by √{}(t) over a repeating interval to fill in the circle. When simulated, this procedure produces a sufficiently uniform distribution of heat throughout the target. Given this pattern, we specify the current as a function of time in the magnets. In our test setup, the circuit's frequency response alters the input pattern, and we are investigating ways to compensate for that effect. University of Richmond.

  12. The effect of irregular breathing patterns on internal target volumes in four-dimensional CT and cone-beam CT images in the context of stereotactic lung radiotherapy

    SciTech Connect

    Clements, N.; Kron, T.; Roxby, P.; Franich, R.; Dunn, L.; Aarons, Y.; Chesson, B.; Siva, S.; Duplan, D.; Ball, D.

    2013-02-15

    Purpose: Stereotactic lung radiotherapy is complicated by tumor motion from patient respiration. Four-dimensional CT (4DCT) imaging is a motion compensation method used in treatment planning to generate a maximum intensity projection (MIP) internal target volume (ITV). Image guided radiotherapy during treatment may involve acquiring a volumetric cone-beam CT (CBCT) image and visually aligning the tumor to the planning 4DCT MIP ITV contour. Moving targets imaged with CBCT can appear blurred and currently there are no studies reporting on the effect that irregular breathing patterns have on CBCT volumes and their alignment to 4DCT MIP ITV contours. The objective of this work was therefore to image a phantom moving with irregular breathing patterns to determine whether any configurations resulted in errors in volume contouring or alignment. Methods: A Perspex thorax phantom was used to simulate a patient. Three wooden 'lung' inserts with embedded Perspex 'lesions' were moved up to 4 cm with computer-generated motion patterns, and up to 1 cm with patient-specific breathing patterns. The phantom was imaged on 4DCT and CBCT with the same acquisition settings used for stereotactic lung patients in the clinic and the volumes on all phantom images were contoured. This project assessed the volumes for qualitative and quantitative changes including volume, length of the volume, and errors in alignment between CBCT volumes and 4DCT MIP ITV contours. Results: When motion was introduced 4DCT and CBCT volumes were reduced by up to 20% and 30% and shortened by up to 7 and 11 mm, respectively, indicating that volume was being under-represented at the extremes of motion. Banding artifacts were present in 4DCT MIP images, while CBCT volumes were largely reduced in contrast. When variable amplitudes from patient traces were used and CBCT ITVs were compared to 4DCT MIP ITVs there was a distinct trend in reduced ITV with increasing amplitude that was not seen when compared to true ITVs

  13. Single Crystal Diamond Beam Position Monitors with Radiofrequency Electronic Readout

    SciTech Connect

    Solar, B.; Graafsma, H.; Potdevin, G.; Trunk, U.; Morse, J.; Salome, M.

    2010-06-23

    Over the energy range 5{approx}30 keV a suitably contacted, thin ({approx}100 {mu}m) diamond plate can be operated in situ as a continuous monitor of X-ray beam intensity and position as the diamond absorbs only a small percentage of the incident beam. Single crystal diamond is a completely homogeneous material showing fast (ns), spatially uniform signal response and negligible (beams. We report on tests made at ESRF and DESY using diamond beam position monitors of simple quadrant electrode designs with metal contacts, operated using wideband electronic readout corresponding to the RF accelerator frequency. The instrumentation for these monitors must cover a large range of operating conditions: different beam sizes, fluxes, energies and time structure corresponding to the synchrotron fill patterns. Sophisticated new RF sampling electronics can satisfy most requirements: using a modified Libera Brilliance readout system, we measured the center of gravity position of a 25 {mu}m beam at the DORIS III F4 beam line at a rate of 130 Msample/s with narrowband filtering of a few MHz bandwidth. Digitally averaging the signal further provided a spatial resolution {approx}20 nm.

  14. Gap-fill type HSQ/ZEP520A bilayer resist process-(II): HSQ island and spacer formation

    NASA Astrophysics Data System (ADS)

    Chen, Wei-Su; Gu, Pei-Yi; Kao, Ming-Jer; Tsai, Ming-Jinn

    2008-03-01

    Hydrogen silsesquioxane (HSQ) bilayer resist (BLR) processes are attractive to obtain nano-sized features with high aspect ratio by dry-transferring thin e-beam pattern to thick underlayer to strengthen the etch resistance. However, there are drawbacks of high e-beam dosage for HSQ patterning and difficulty in controlling the underlayer resist profile by O2 plasma with anisotropic etching. In this study gap-fill type HSQ/ZEP520A BLR processes were studied to overcome these problems. The advantage of gap-fill type BLR processes is that the dosage for patterning on thick ZEP520A e-beam positive resist is not as high as that for HSQ and the resist profile can be tuned by exposure and development processes without depending on O2 plasma. By gap-filling of HSQ in ZEP520A trench patterns and then stripping ZEP520A by O2 plasma the tone is conversed from trench to line. The gap filling quality attributes include (1) the void size and number of HSQ lines and (2) spacer adhesion on HSQ line edge. Only the non-diluted HSQ solution could completely fill the trench and the HSQ line formed after stripping of ZEP520A. The spacer formed by diluted HSQ is found to be composed of oxide without any ZEP520A-related elements by FTIR analysis. The ZEP520A trench CD monotonically increases with decrease of W/L ratio. The HSQ line CD also follows the same trend. The extension of HSQ in ZEP520A, i.e. HSQ line CD minus ZEP520A trench CD, basically follows the reverse trend. It is therefore concluded that extension of HSQ lines in ZEP520A and HSQ spacers are formed from the diffused HSQ in trench sidewall without any reaction with ZEP520A. Voids were generally observed at the bottom of the HSQ line. Size and quantity of voids are larger for lower W/L ratios, indicating that the voids were formed due to insufficient HSQ volume for gap-filling. Increasing e-beam dose, baking or reflow temperature, and reflow of ZEP520A before HSQ coating could reduce the void formation. Multiple gap-filling

  15. Hydrogen Filling Station

    SciTech Connect

    Boehm, Robert F; Sabacky, Bruce; Anderson II, Everett B; Haberman, David; Al-Hassin, Mowafak; He, Xiaoming; Morriseau, Brian

    2010-02-24

    future. Project partners also conducted a workshop on hydrogen safety and permitting. This provided an opportunity for the various permitting agencies and end users to gather to share experiences and knowledge. As a result of this workshop, the permitting process for the hydrogen filling station on the Las Vegas Valley Water District’s land was done more efficiently and those who would be responsible for the operation were better educated on the safety and reliability of hydrogen production and storage. The lessons learned in permitting the filling station and conducting this workshop provided a basis for future hydrogen projects in the region. Continuing efforts to increase the working pressure of electrolysis and efficiency have been pursued. Research was also performed on improving the cost, efficiency and durability of Proton Exchange Membrane (PEM) hydrogen technology. Research elements focused upon PEM membranes, electrodes/catalysts, membrane-electrode assemblies, seals, bipolar plates, utilization of renewable power, reliability issues, scale, and advanced conversion topics. Additionally, direct solar-to-hydrogen conversion research to demonstrate stable and efficient photoelectrochemistry (PEC) hydrogen production systems based on a number of optional concepts was performed. Candidate PEC concepts included technical obstacles such as inefficient photocatalysis, inadequate photocurrent due to non-optimal material band gap energies, rapid electron-hole recombination, reduced hole mobility and diminished operational lifetimes of surface materials exposed to electrolytes. Project Objective 1: Design, build, operate hydrogen filling station Project Objective 2: Perform research and development for utilizing solar technologies on the hydrogen filling station and convert two utility vehicles for use by the station operators Project Objective 3: Increase capacity of hydrogen filling station; add additional vehicle; conduct safety workshop; develop a roadmap for

  16. BEAM-BEAM 2003 SUMMARY.

    SciTech Connect

    FISCHER,W.SEN,T.

    2003-05-19

    This paper summarizes the presentations and discussions of the Beam-Beam'03 workshop, held in Montauk, Long Island, from May 19 to 23, 2003. Presentations and discussions focused on halo generation from beam-beam interactions; beam-beam limits, especially coherent limits and their effects on existing and future hadron colliders; beam-beam compensation techniques, particularly for long-range interactions; and beam-beam study tools in theory, simulation, and experiment.

  17. Three-dimensional profilometry of microlenses by phase shifting interferometery using nematic liquid crystal material filled cell as a phase modulator.

    PubMed

    Inam, M; Srivastava, V; Mehta, D S

    2015-02-10

    In this paper, we report the use of a nematic liquid crystal material filled cell in transmission mode as a voltage controlled phase modulator for the characterization of microlenses. In one arm of the Mach-Zehnder interferometer, a nematic liquid crystal filled cell with DC voltage connection was placed, and in another arm of the interferometer microlenses with a 4-F imaging system were placed. Interference takes place between the light beams coming from the two arms of the Mach-Zehnder interferometer, one after passing through the nematic liquid crystal cell and another after passing through microlenses. Interference patterns were recorded by a CCD camera. By applying DC voltage to the nematic liquid crystal filled cell, various phase shifted interferograms were recorded, and from phase shifted interferograms, the shape and size of microlenses were determined. The results of the reconstructed profile of the microlenses are compared with white-light profilometry.

  18. Optical generation of crystalline, quasicrystalline, and arbitrary arrays of torons in confined cholesteric liquid crystals for patterning of optical vortices in laser beams

    NASA Astrophysics Data System (ADS)

    Ackerman, Paul J.; Qi, Zhiyuan; Smalyukh, Ivan I.

    2012-08-01

    Condensed matter systems with topological defects in the ground states range from the Abrikosov phases in superconductors, to various blue phases and twist grain boundary phases in liquid crystals, and to phases of skyrmion lattices in chiral ferromagnets and Bose-Einstein condensates. In nematic and chiral nematic liquid crystals, which are true fluids with long-range orientational ordering of constituent molecules, point and line defects spontaneously occur as a result of symmetry-breaking phase transitions or due to flow, but they are unstable, hard to control, and typically annihilate with time. Here we describe the optical generation of two-dimensional crystalline, quasicrystalline, and arbitrary ensembles of particlelike structures manifesting both skyrmionlike and Hopf fibration features—dubbed “torons”—composed of looped double twist cylinders and point defects embedded in a uniform director field. In these two-dimensional lattices, we then introduce various dislocations, defects in positional ordering of the torons. We show that the periodic defect lattices with and without dislocation are light- and voltage-tunable reconfigurable two-dimensional diffraction gratings and can be used to generate various controlled phase singularities in the diffracted laser beams. The results of computer simulations of optical images, diffraction patterns, and phase distributions with optical vortices are in a good agreement with the corresponding experimental findings.

  19. Evaluation of upper airways after bimaxillary orthognathic surgery in patients with skeletal Class III pattern using cone-beam computed tomography

    PubMed Central

    Azevêdo, Marília Spínola; Machado, Andre Wilson; Barbosa, Inêssa da Silva; Esteves, Lucas Senhorinho; Rocha, Vanessa Álvares Castro; Bittencourt, Marcos Alan Vieira

    2016-01-01

    Introduction: It has been suggested that mandibular setback surgery, combined or not with maxillary advancement as a treatment alternative for patients with mandibular prognathism, can induce changes in upper airway space (UAS). Therefore, this study aimed to assess the response of the upper airway in the oropharynx region of patients with Class III skeletal pattern that underwent bimaxillary orthognathic surgery (maxillary advancement and mandibular setback) combined with mentoplasty. Material and Methods: The sample comprised 26 cone-beam computed tomography (CBCT) scans of 13 patients. The examination was taken before and after surgery. UAS volume, sagittal area, length and minimal axial area with its width, depth and location, were measured with the aid of Dolphin ImagingTMsoftware version 11.5 Premium. Data were statistically treated by applying Shapiro-Wilk test and Student's paired t-test, considering as statistically significant the results of which p-value was lower than 0.05. Results: No statistically significant differences were found in any measurements evaluated. Conclusions: No significant changes were observed in the oropharynx after bimaxillary orthognathic surgery and mentoplasty. PMID:27007759

  20. Lava-Filled Craters

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Released 12 June 2003

    Craters and hills form high standing streamlined plateaus or islands in a channeled area. The plateaus are rounded in the upstream direction and taper to a point in the downstream direction, indicating that the direction of flow in this area was roughly south to north, or bottom to top. The channels appear to be filled with lava flow deposits that are raised above the channel in some areas. A lava flow diverges around a small streamlined hill near the bottom of the image and then merges again around the northern end of it. Near the top of the image is a crater with a breach on the east (right) side that allowed the lava to flow in, leaving a lobate, high standing deposit. The channels may have been formed by the lava flows that currently fill them or there may have been flow of liquid water that created them before the lava was emplaced.

    Image information: VIS instrument. Latitude 16, Longitude 183 East (177 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built

  1. High-fidelity dummy fill printing with repair OPC

    NASA Astrophysics Data System (ADS)

    Lin, Louis; Wang, Wei-Long; McGowan, Sarah

    2013-09-01

    Dummy fill plays a crucial role on both controlling topography uniformity and ensuring device performance by manipulating homogenous pattern density. There are several types of fill to achieve this purpose on advanced technologies. The conventional way is to place them out of optical ambit range from main features as reference for Optical Proximity Correction (OPC) procedure, but it degrades the FILL performance due to leaving considerable empty space between FILL and main features. The aggressive way is to place FILL as close as main features to perfectly achieve uniform pattern density. However, in this way, it's challenge to produce defect-free FILL in ORC (Optical Review Check) without applying model-based OPC on FILL which boost the OPC cycle time significantly. In this paper, we propose a novel approach by in-stage Repair OPC technique to not only accurately print aggressive placement FILL on the wafer accurately but also reduce the impact of run time cost on full chip OPC processing.

  2. Beam-beam simulations for separated beams

    SciTech Connect

    Furman, Miguel A.

    2000-04-10

    We present beam-beam simulation results from a strong-strong gaussian code for separated beams for the LHC and RHIC. The frequency spectrum produced by the beam-beam collisions is readily obtained and offers a good opportunity for experimental comparisons. Although our results for the emittance blowup are preliminary, we conclude that, for nominal parameter values, there is no significant difference between separated beams and center-on-center collisions.

  3. Characteristics of microdomains and microdomain patterns recorded by electron beam irradiation on Y-cut LiNbO3 crystals

    NASA Astrophysics Data System (ADS)

    Kokhanchik, L. S.; Gainutdinov, R. V.; Lavrov, S. D.; Volk, T. R.

    2015-08-01

    We present the results of investigations of planar domain patterns (isolated domains and domain gratings) fabricated by irradiation of the nonpolar Y-surface of LiNbO3 crystals by an electron beam (EB) incident normally onto the surface. The EB recorded domains were investigated using atomic force microscopy, confocal second harmonic generation microscopy, and chemical etching as an auxiliary method. The dependence of the domain characteristics on irradiation conditions (acceleration voltage U, EB current I, and irradiation time tirr) were determined. The length Ld of both isolated domains and domain gratings along the polar axis Z grows linearly with tirr (at U, I = const) with no tending to saturation. The plots Ld(tirr) obtained for U = 10 and 15 kV are practically identical, whereas the values of Ld for U = 5 kV are essentially lower. The domain thickness Td along the Y-direction, i.e., the depth of the switched layer grows with acceleration voltage U. These results are discussed in terms of space-charge fields formation arising under EB irradiation of insulators. The linearity of Ld(tirr) is accounted for by the frontal domain growth via the viscous friction law. The experimental dependence of Td on U supports the suggestion that the domain thickness is determined by the penetration depth Re of primary electrons, which in turn is governed by U. The difference in Ld(tirr) plots for different U is accounted for by different electron emission σ. Indirect evidences of a defect structure modification in a thin surface layer with respect to the crystal bulk are obtained.

  4. Intermittent Surface Water Connectivity: Fill and Spill vs. Fill ...

    EPA Pesticide Factsheets

    Intermittent surface connectivity can influence aquatic systems, since chemical and biotic movements are often associated with water flow. Although often referred to as fill and spill, wetlands also fill and merge. We examined the effects of these connection types on water levels, ion concentrations, and biotic communities of eight prairie pothole wetlands between 1979 and 2015. Fill and spill caused pulsed surface water connections that were limited to periods following spring snow melt. In contrast, two wetlands connected through fill and merge experienced a nearly continuous, 20-year surface water connection and had completely coincident water levels. Fill and spill led to minimal convergence in dissolved ions and macroinvertebrate composition, while these constituents converged under fill and merge. The primary factor determining difference in responses was duration of the surface water connection between wetland pairs. Our findings suggest that investigations into the effects of intermittent surface water connections should not consider these connections generically, but need to address the specific types of connections. In particular, fill and spill promotes external water exports while fill and merge favors internal storage. The behaviors of such intermittent connections will likely be accentuated under a future with more frequent and severe climate extremes. Under the Safe and Sustainable Water Resources National Program, work is being done to qu

  5. Ion beam lithography system

    DOEpatents

    Leung, Ka-Ngo

    2005-08-02

    A maskless plasma-formed ion beam lithography tool provides for patterning of sub-50 nm features on large area flat or curved substrate surfaces. The system is very compact and does not require an accelerator column and electrostatic beam scanning components. The patterns are formed by switching beamlets on or off from a two electrode blanking system with the substrate being scanned mechanically in one dimension. This arrangement can provide a maskless nano-beam lithography tool for economic and high throughput processing.

  6. The E-beam resist test facility: performance testing and benchmarking of E-beam resists for advanced mask writers

    NASA Astrophysics Data System (ADS)

    Malloy, Matt; Jang, Il Yong; Mellish, Mac; Litt, Lloyd C.; Raghunathan, Ananthan; Hartley, John

    2012-11-01

    With each new generation of e-beam mask writers comes the ability to write leading edge photomasks with improved patterning performance and increased throughput. However, these cutting-edge e-beam tools are often used with older generation resists, preventing the end-user from taking full advantage of the tool's potential. The generation gap between tool and resist will become even more apparent with the commercialization of multi-beam mask writers, which are expected to be available for pilot line use around 2015. The mask industry needs resists capable of meeting the resolution, roughness, and sensitivity requirements of these advanced tools and applications. The E-beam Resist Test Facility (ERTF) has been established to fill the need for consortium-based testing of e-beam resists for mask writing applications on advanced mask writers out to the 11nm half-pitch node and beyond. SEMATECH and the College of Nanoscale Science and Engineering (CNSE) began establishing the ERTF in early 2012 to test e-beam resist samples from commercial suppliers and university labs against the required performance metrics for each application at the target node. Operations officially began on June 12, 2012, at which time the first e-beam resist samples were tested. The ERTF uses the process and metrology infrastructure available at CNSE, including a Vistec VB300 Vectorscan e-beam tool adjusted to operate at 50kv. Initial testing results show that multiple resists already meet, or are close to meeting, the resolution requirements for mask writing at the 11nm node, but other metrics such as line width roughness still need improvement. An overview of the ERTF and its capabilities is provided here. Tools, baseline processes, and operation strategy details are discussed, and resist testing and benchmarking results are shown. The long-term outlook for the ERTF and plans to expand capability and testing capacity, including resist testing for e-beam direct write lithography, are also

  7. Orientation Dependence of Linewidth Variation in sub-50-nm Gaussian e-beam Lithography and its Correction

    SciTech Connect

    Lu,M.; Tennant, D.; Jacobsen, C.

    2006-01-01

    The width of tilted line patterns, such as are needed when drawing circular structures, is found to vary with the oblique angle when it falls into the sub-50-nm scale in Gaussian e-beam lithography. The authors analysis shows that this orientation dependence of linewidth variation originates from the nonuniformity of discrete primitive filling in Cartesian coordinates. Two correction schemes based on pattern segmentation are proposed. Test exposures of high resolution zone plate patterns show that both two schemes work well; a double-insert scheme is superior in terms of dose distribution uniformity.

  8. Analysis of a ceramic filled bio-plastic composite sandwich structure

    SciTech Connect

    Habib Ullah, M.; Islam, M. T.

    2013-11-25

    Design and analysis of a ceramic-filled bio-plastic composite sandwich structure is presented. This proposed high-dielectric structure is used as a substrate for patch antennas. A meandered-strip line-fed fractal-shape patch antenna is designed and fabricated on a copper-laminated sandwich-structured substrate. Measurement results of this antenna show 44% and 20% of bandwidths with maximum gains of 3.45 dBi and 5.87 dBi for the lower and upper bands, respectively. The half-power beam widths of 104° and 78° have been observed from the measured radiation pattern at the two resonance frequencies 0.9 GHz and 2.5 GHz.

  9. Plasma-filled diode based on the coaxial gun

    SciTech Connect

    Zherlitsyn, A. A.; Kovalchuk, B. M.; Pedin, N. N.

    2012-10-15

    The paper presents the results of studies of a coaxial gun for a plasma-filled electron diode. Effects of the discharge channel diameter and gun current on characteristics of the plasma and pulse generated in the diode were investigated. The electron beam with maximum energy of {>=}1 MeV at the current of Almost-Equal-To 100 kA was obtained in the experiments with a plasma-filled diode. The energy of Almost-Equal-To 5 kJ with the peak power of {>=}100 GW dissipated in the diode.

  10. Plasma-filled diode based on the coaxial gun

    NASA Astrophysics Data System (ADS)

    Zherlitsyn, A. A.; Kovalchuk, B. M.; Pedin, N. N.

    2012-10-01

    The paper presents the results of studies of a coaxial gun for a plasma-filled electron diode. Effects of the discharge channel diameter and gun current on characteristics of the plasma and pulse generated in the diode were investigated. The electron beam with maximum energy of ≥1 MeV at the current of ≈100 kA was obtained in the experiments with a plasma-filled diode. The energy of ≈5 kJ with the peak power of ≥100 GW dissipated in the diode.

  11. Plasma-filled diode based on the coaxial gun.

    PubMed

    Zherlitsyn, A A; Kovalchuk, B M; Pedin, N N

    2012-10-01

    The paper presents the results of studies of a coaxial gun for a plasma-filled electron diode. Effects of the discharge channel diameter and gun current on characteristics of the plasma and pulse generated in the diode were investigated. The electron beam with maximum energy of ≥1 MeV at the current of ≈100 kA was obtained in the experiments with a plasma-filled diode. The energy of ≈5 kJ with the peak power of ≥100 GW dissipated in the diode.

  12. MTR-Fill: A Simulated Annealing-Based X-Filling Technique to Reduce Test Power Dissipation for scan-Based Designs

    NASA Astrophysics Data System (ADS)

    Song, Dong-Sup; Ahn, Jin-Ho; Kim, Tae-Jin; Kang, Sungho

    This paper proposes the minimum transition random X-filling (MTR-fill) technique, which is a new X-filling method, to reduce the amount of power dissipation during scan-based testing. In order to model the amount of power dissipated during scan load/unload cycles, the total weighted transition metric (TWTM) is introduced, which is calculated by the sum of the weighted transitions in a scan-load of a test pattern and a scan-unload of a test response. The proposed MTR-fill is implemented by simulated annealing method. During the annealing process, the TWTM of a pair of test patterns and test responses are minimized. Simultaneously, the MTR-fill attempts to increase the randomness of test patterns in order to reduce the number of test patterns needed to achieve adequate fault coverage. The effectiveness of the proposed technique is shown through experiments for ISCAS' 89 benchmark circuits.

  13. Concentric Crater Fill

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    The bizarre patterns on the floor of this crater in Nilosyrtis Mensae defy an easy explanation. At 34 degrees north latitude, this location hardly qualifies as 'Arctic' yet it is likely that some form of periglacial process possibly combined with the vaporization of ground ice is responsible for this intriguing landscape.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

    Image information: VIS instrument. Latitude 10.3, Longitude 24.5 East (284.5 West). 19 meter/pixel resolution.

  14. Method and apparatus for analyzing the fill characteristics of a packaging container

    DOEpatents

    Rodriguez, J.G.

    1998-10-13

    A system is described for analyzing the fill characteristics of a container. A container having a filling material therein is positioned adjacent a sound generator. Sound waves from the generator are applied to the container, causing it to vibrate. A vibration detector is used to determine the amount of container vibration. A preferred vibration detector involves a laser vibrometer which applies a reference laser beam to the vibrating container. The reference beam is reflected off of the container to generate a reflected laser beam. The reflected beam experiences a Doppler frequency shift compared with the reference beam which is caused by container vibration. The Doppler shift of the reflected beam is then compared with standardized Doppler shift data from a control container. Repeated Doppler shift measurements may also be undertaken which are converted into a vibration profile that is compared with a standardized vibration profile from a control container. 4 figs.

  15. Method and apparatus for analyzing the fill characteristics of a packaging container

    DOEpatents

    Rodriguez, Julio G.

    1998-01-01

    A system for analyzing the fill characteristics of a container. A container having a filling material therein is positioned adjacent a sound generator. Sound waves from the generator are applied to the container, causing it to vibrate. A vibration detector is used to determine the amount of container vibration. A preferred vibration detector involves a laser vibrometer which applies a reference laser beam to the vibrating container. The reference beam is reflected off of the container to generate a reflected laser beam. The reflected beam experiences a Doppler frequency shift compared with the reference beam which is caused by container vibration. The Doppler shift of the reflected beam is then compared with standardized Doppler shift data from a control container. Repeated Doppler shift measurements may also be undertaken which are converted into a vibration profile that is compared with a standardized vibration profile from a control container.

  16. Gas-filled hohlraum study on Shenguang-III prototype

    NASA Astrophysics Data System (ADS)

    Yang, Dong; Li, Sanwei; Li, Zhichao; Yi, Rongqing; Guo, Liang; Jiang, Xiaohua; Liu, Shenye; Yang, Jiamin; Jiang, Shaoen; Ding, Yongkun; Hao, Liang; Zhang, Huasen; Zhao, Yiqing; Zou, Shiyang; Huo, Wenyi; Li, Xin

    2015-11-01

    Experimental studies on gas-filled hohlraum were performed extensively in recent years on Shenguang-III prototype laser facility. These experiments employed Au hohlraums within C5H12 gas fill heated by smoothing beams. In the first round of experiments, although the low-Z gas fill impeded the blow-off plasma ablated from hohlraum wall, the x-ray flux from the LEH decreased dramatically compared with the vacuum hohlraum. Further analysis of several ways of energy deposition including heating the gas-fill, extra scattered light and ablating the LEH membrane, revealed that too much laser energy were wasted in exploding the LEH membrane if we use a 1 ns square pulse. After we introduced a low power prepulse to intentionally exploding the membrane, the behavior of the x-ray flux from the gas-filled hohlraum is identical with the vacuum hohlraum. In subsequent studies, the motion of x-ray spot and corona plasma has also been studied using the gas-filled hohlraum. We obtained high quality data of the gas/wall interface and the boundary of the ablated wall near the LEH. The result agrees with that in simulation. However, there is a discrepancy between the experiment and the simulation in the spatial feature of the ablated wall near the LEH extracted from M-band x-ray image.

  17. Cartesian beams.

    PubMed

    Bandres, Miguel A; Gutiérrez-Vega, Julio C

    2007-12-01

    A new and very general beam solution of the paraxial wave equation in Cartesian coordinates is presented. We call such a field a Cartesian beam. The complex amplitude of the Cartesian beams is described by either the parabolic cylinder functions or the confluent hypergeometric functions, and the beams are characterized by three parameters that are complex in the most general situation. The propagation through complex ABCD optical systems and the conditions for square integration are studied in detail. Applying the general expression of the Cartesian beams, we also derive two new and meaningful beam structures that, to our knowledge, have not yet been reported in the literature. Special cases of the Cartesian beams are the standard, elegant, and generalized Hermite-Gauss beams, the cosine-Gauss beams, the Lorentz beams, and the fractional order beams.

  18. Handbook for Gas Filled RF Cavity Aficionados'

    SciTech Connect

    Tollestrup, A.V.; Chung, Moses; Yonehara, Katsuya; /Fermilab

    2009-05-01

    The use of hydrogen gas filled RF cavities in muon cooling channels has been proposed by Rolland Johnson. Impressive results have been obtained toward attaining high voltage gradients and rapid training in preliminary tests done at the FNAL MTA facility. However, so far it has not been possible to test them under conditions where they were subject to the transversal of a high intensity particle beam. This note is an attempt to bring together a description of some of the pertinent physical processes that take place in the dilute plasma that is generated in the hydrogen gas by the beam. Two effects dominate. The first is that the free electrons generated can load down the cavity and transfer its energy to heating the gas. The second is a question of what happens to the plasma in the longer term. There is an enormous literature on the subject of the subject of dilute hydrogen plasmas and we can tap into this information in order to understand and predict the behavior of the cavity.

  19. Reticle and wafer CD variation for different dummy pattern

    NASA Astrophysics Data System (ADS)

    Ning, GuoXiang; Buergel, Christian; Ackmann, Paul; Staples, Marc; Thamm, Thomas; Lim, Chin Teong; Leschok, Andre; Roling, Stefan; Zhou, Anthony; Gn, Fang Hong; Richter, Frank

    2012-11-01

    Dummy pattern fill is added to a layout of a reticle for the purpose of raising the pattern-density of specific regions. The pattern-density has also an influence on different process-steps which were performed when manufacturing a reticle (e.g. proximity effect of electron beam exposure process, developer, and etch-processes). Although the reticle processes are set up to compensate the influence of the pattern density, dummy pattern can have an influence onto the reticle CD. When the isolated features become "nested" by insertion of dummy pattern, the reticle CD variation is even larger because nested features exacerbate the proximity effect of an electron beam. Another reason is that the etch ratio as well as the develop dynamics during the reticle manufacturing process are slightly dependent on the local pattern-density of pattern. With different dummy pattern around the main feature, the final reticle CD will be changed. Wafer CD of main feature is also dependant on the surrounding patterns which will induce different boundary conditions for wafer exposure. We have investigated three manufacturing sites for a 28nm first-metal layer reticle. Two of them were manufactured with a comparable process using the same advanced reticle binary blank material. For the third site a different reticle blank material with a relatively thin absorber layer thickness was used which was made with a comparable reticle process. The optical proximity correction (OPC) test patterns were designed with two different dummy patterns. The CD differences of the three reticles will be demonstrated for different dummy pattern and will be discussed individually. All three reticles have been exposed and the respective wafer critical dimension through pitch (CDTP) and linearity performance is demonstrated. Also the line-end performance for two dimensional (2D) structures is shown for the three sites of the reticle. The wafer CD difference for CDTP, linearity, and 2D structures are also

  20. Coherence delay augmented laser beam homogenizer

    DOEpatents

    Rasmussen, P.; Bernhardt, A.

    1993-06-29

    The geometrical restrictions on a laser beam homogenizer are relaxed by ug a coherence delay line to separate a coherent input beam into several components each having a path length difference equal to a multiple of the coherence length with respect to the other components. The components recombine incoherently at the output of the homogenizer, and the resultant beam has a more uniform spatial intensity suitable for microlithography and laser pantogography. Also disclosed is a variable aperture homogenizer, and a liquid filled homogenizer.

  1. Coherence delay augmented laser beam homogenizer

    DOEpatents

    Rasmussen, Paul; Bernhardt, Anthony

    1993-01-01

    The geometrical restrictions on a laser beam homogenizer are relaxed by ug a coherence delay line to separate a coherent input beam into several components each having a path length difference equal to a multiple of the coherence length with respect to the other components. The components recombine incoherently at the output of the homogenizer, and the resultant beam has a more uniform spatial intensity suitable for microlithography and laser pantogography. Also disclosed is a variable aperture homogenizer, and a liquid filled homogenizer.

  2. Novel spin-on metal hardmask materials for filling applications

    NASA Astrophysics Data System (ADS)

    Dioses, Alberto D.; Chada, Venkata; Wolfer, Elizabeth; Ng, Edward; Mullen, Salem; Yao, Huirong; Cho, JoonYeon; Padmanaban, Munirathna

    2014-03-01

    Hardmasks are indispensable materials during pattern transfer to the desired substrates in the semiconductor manufacturing process. Primarily there are two types of hardmask materials - organic and inorganic - and they can be coated onto substrates or underlying materials either by a simple spin-on process or by more expensive methods such as chemical vapor deposition (CVD), atomic layer deposition (ALD) and sputtering process. Most inorganic hardmasks such as SiO2, SiON, SiN and TiN are deposited using the CVD process. Future nodes require hardmasks with high etch resistance as the designs move from horizontal to vertical (3D). We have reported novel spin-on metallic hardmasks (MHM) with comparable or higher etch resistance than SiO2.1-2 In addition to high etch resistance, they are easy to remove using wet etch chemicals. The spin-on process offers high throughput and commonly used spin tracks can be utilized; thereby reducing overall process costs when compared with CVD. Via-fill performance is also an important attribute of hardmask materials for these future nodes. Organic spin-on materials, both siloxane- and carbon-based, are used in filling applications of deep via or deep trench fill, such as those found in LELE double-patterning schemes. Inorganic materials deposited by either chemical vapor deposition (CVD) or atomic layer deposition (ALD) have higher resistance to oxygenated plasma than organic materials, but are hindered by their poor filling performance. Therefore, novel tungsten (W) containing MHM materials having both good filling performance and higher resistance to oxygenated plasma than organic materials would be of value in some filling applications. The present paper describes specific metal oxides useful for filling applications. In addition to basic filling performance and etch resistance, other properties such as optical properties, outgas and shelf life via forced aging etc. will be discussed.

  3. Filling carbon nanotubes with particles.

    PubMed

    Kim, Byong M; Qian, Shizhi; Bau, Haim H

    2005-05-01

    The filling of carbon nanotubes (CNTs) with fluorescent particles was studied experimentally and theoretically. The fluorescent signals emitted by the particles were visible through the walls of the nanotubes, and the particles inside the tubes were observable with an electron microscope. Taking advantage of the template-grown carbon nanotubes' transparency to fluorescent light, we measured the filling rate of the tubes with particles at room conditions. Liquids such as ethylene glycol, water, and ethylene glycol/water mixtures, laden with 50 nm diameter fluorescent particles, were brought into contact with 500 nm diameter CNTs. The liquid and the particles' transport were observed, respectively, with optical and fluorescence microscopy. The CNTs were filled controllably with particles by the complementary action of capillary forces and the evaporation of the liquid. The experimental results were compared and favorably agreed with theoretical predictions. This is the first report on fluorescence studies of particle transport in carbon nanotubes.

  4. Paleovalley fills: Trunk vs. tributary

    USGS Publications Warehouse

    Kvale, E.P.; Archer, A.W.

    2007-01-01

    A late Mississippian-early Pennsylvanian eustatic sea level drop resulted in a complex lowstand drainage network being eroded across the Illinois Basin in the eastern United States. This drainage system was filled during the early part of the Pennsylvanian. Distinct differences can be recognized between the trunk and tributary paleovalley fills. Fills preserved within the trunk systems tend to be fluvially dominated and consist of bed-load deposits of coarse- to medium-grained sandstone and conglomerate. Conversely, the incised valleys of tributary systems tend to be filled with dark mudstone, thinly interbedded sandstones, and mudstones and siltstones. These finer grained facies exhibit marine influences manifested by tidal rhythmites, certain traces fossils, and macro- and microfauna. Examples of tributary and trunk systems, separated by no more than 7 km (4.3 mi) along strike, exhibit these styles of highly contrasting fills. Useful analogs for understanding this Pennsylvanian system include the Quaternary glacial sluiceways present in the lower Ohio, White, and Wabash river valleys of Indiana (United States) and the modern Amazon River (Brazil). Both the Amazon River and the Quaternary rivers of Indiana have (or had) trunk rivers that are (were) dominated by large quantities of bed load relative to their tributaries. The trunk valley systems of these analogs aggraded much more rapidly than their tributary valleys, which evolved into lakes because depositional rates along the trunk are (were) so high that the mouths of the tributaries have been dammed by bed-load deposits. These Holocene systems illustrate that sediment yields can significantly influence the nature of fill successions within incised valleys independent of rates of sea level changes or proximity to highstand coastlines. Copyright ?? 2007. The American Association of Petroleum Geologists. All rights reserved.

  5. QENS investigation of filled rubbers

    NASA Astrophysics Data System (ADS)

    Triolo, A.; Lo Celso, F.; Negroni, F.; Arrighi, V.; Qian, H.; Lechner, R. E.; Desmedt, A.; Pieper, J.; Frick, B.; Triolo, R.

    The polymer segmental dynamics is investigated in a series of silica-filled rubbers. The presence of inert fillers in polymers greatly affects the mechanical and physical performance of the final materials. For example, silica has been proposed as a reinforcing agent of elastomers in tire production. Results from quasielastic neutron scattering and Dynamic Mechanical Thermal Analysis (DMTA) measurements are presented on styrene-ran-butadiene rubber filled with silica. A clear indication is obtained of the existence of a bimodal dynamics, which can be rationalized in terms of the relaxation of bulk rubber and the much slower relaxation of the rubber adsorbed on the filler surface.

  6. Optical fiber antenna generating spiral beam shapes

    SciTech Connect

    Sarkar Pal, S.; Mondal, S. K. Kumar, R.; Akula, A.; Ghosh, R.; Bhatnagar, R.; Kumbhakar, D.

    2014-01-20

    A simple method is proposed here to generate vortex beam and spiral intensity patterns from a Gaussian source. It uses a special type of optical fiber antenna of aperture ∼80 nm having naturally grown surface curvature along its length. The antenna converts linearly polarized Gaussian beam into a beam with spiral intensity patterns. The experimentally obtained spiral patterns with single and double spiral arms manifest the orbital angular momentum, l = ±1, 2, carried by the output beam. Such beam can be very useful for optical tweezer, metal machining, and similar applications.

  7. Can-Filled Crash Barrier

    NASA Technical Reports Server (NTRS)

    Wilson, A. H.

    1983-01-01

    Crash barrier composed largely of used aluminum beverage cans protects occupants of cars in collisions with poles or trees. Lightweight, can-filled barrier very effective in softening impact of an automobile in head-on and off-angle collisions. Preliminary results indicate barrier is effective in collisions up to 40 mi/h (64 km/h).

  8. Filling in the retinal image

    NASA Technical Reports Server (NTRS)

    Larimer, James; Piantanida, Thomas

    1990-01-01

    The optics of the eye form an image on a surface at the back of the eyeball called the retina. The retina contains the photoreceptors that sample the image and convert it into a neural signal. The spacing of the photoreceptors in the retina is not uniform and varies with retinal locus. The central retinal field, called the macula, is densely packed with photoreceptors. The packing density falls off rapidly as a function of retinal eccentricity with respect to the macular region and there are regions in which there are no photoreceptors at all. The retinal regions without photoreceptors are called blind spots or scotomas. The neural transformations which convert retinal image signals into percepts fills in the gaps and regularizes the inhomogeneities of the retinal photoreceptor sampling mosaic. The filling-in mechamism plays an important role in understanding visual performance. The filling-in mechanism is not well understood. A systematic collaborative research program at the Ames Research Center and SRI in Menlo Park, California, was designed to explore this mechanism. It was shown that the perceived fields which are in fact different from the image on the retina due to filling-in, control some aspects of performance and not others. Researchers have linked these mechanisms to putative mechanisms of color coding and color constancy.

  9. Space-filling polyhedral sorbents

    DOEpatents

    Haaland, Peter

    2016-06-21

    Solid sorbents, systems, and methods for pumping, storage, and purification of gases are disclosed. They derive from the dynamics of porous and free convection for specific gas/sorbent combinations and use space filling polyhedral microliths with facial aplanarities to produce sorbent arrays with interpenetrating interstitial manifolds of voids.

  10. Unsteady Capillary Filling By Electrocapillarity

    NASA Astrophysics Data System (ADS)

    Kang, In Seok; Lee, Jung A.

    2016-11-01

    Unsteady filling of electrolyte solution inside a nanochannel by the electrocapillarity effect is studied. The filling rate is predicted as a function of the bulk concentration of the electrolyte, the surface potential (or surface charge density), and the cross sectional shape of the channel. Since the driving force of the flow is the electrocapillarity, it is first analyzed by using the solution of the Poisson-Boltzmann equation. From the analysis, it is found that the results for many different cross sectional shapes can be unified with good accuracy if the hydraulic radius is adopted as the characteristic length scale of the problem. Especially in the case of constant surface potential, for both limits of κh -> 0 and κh -> ∞ , it can be shown theoretically that the electrocapillarity is independent of the cross sectional shape if the hydraulic radius is the same. In order to analyze the geometric effects more systematically, we consider the regular N-polygons with the same hydraulic radius and the rectangles of different aspect ratios. Washburn's approach is then adopted to predict the filling rate of electrolyte solution inside a nanaochannel. It is found that the average filling velocity decreases as N increases in the case of regular N-polygons with the same hydraulic radius. This is because of that the regular N-polygons of the same hydraulic radius share the same inscribing circle. This work has been supported by BK21+ program.

  11. Sharp transition from ripple patterns to a flat surface for ion beam erosion of Si with simultaneous co-deposition of iron

    NASA Astrophysics Data System (ADS)

    Zhang, K.; Brötzmann, M.; Hofsäss, H.

    2012-09-01

    We investigate pattern formation on Si by sputter erosion under simultaneous co-deposition of Fe atoms, both at off-normal incidence, as function of the Fe surface coverage. The patterns obtained for 5 keV Xe ion irradiation at 30° incidence angle are analyzed with atomic force microscopy. Rutherford backscattering spectroscopy of the local steady state Fe content of the Fe-Si surface layer allows a quantitative correlation between pattern type and Fe coverage. With increasing Fe coverage the patterns change, starting from a flat surface at low coverage (< 2×1015 Fe/cm2) over dot patterns (2-8×1015 Fe/cm2), ripples patterns (8-17×1015 Fe/cm2), pill bug structures (1.8×1016 Fe/cm2) and a rather flat surface with randomly distributed weak pits at high Fe coverage (>1.8×1016 Fe/cm2). Our results confirm the observations by Macko et al. for 2 keV Kr ion irradiation of Si with Fe co-deposition. In particular, we also find a sharp transition from pronounced ripple patterns with large amplitude (rms roughness ˜ 18 nm) to a rather flat surface (rms roughness ˜ 0.5 nm). Within this transition regime, we also observe the formation of pill bug structures, i.e. individual small hillocks with a rippled structure on an otherwise rather flat surface. The transition occurs within a very narrow regime of the steady state Fe surface coverage between 1.7 and 1.8×1016 Fe/cm2, where the composition of the mixed Fe-Si surface layer of about 10 nm thickness reaches the stoichiometry of FeSi2. Phase separation towards amorphous iron silicide is assumed as the major contribution for the pattern formation at lower Fe coverage and the sharp transition from ripple patterns to a flat surface.

  12. Laser propagation in simulations of low fill density hohlraums

    NASA Astrophysics Data System (ADS)

    Meezan, Nathan; Berzak Hopkins, L. F.; Izumi, N.; Divol, L.; Hinkel, D. E.; Ralph, J. E.; Moody, J. D.; Callahan, D. A.

    2016-10-01

    We present analysis of laser propagation in simulations of low fill density hohlraums on the National Ignition Facility (NIF). Simulations using the radiation hydrodynamic code hydra are compared in 2D and 3D. The absorption of laser rays in different materials and spatial locations is extracted from the simulations to identify where and when the inner cone laser beams undergo significant absorption. Inner cone laser beams can be absorbed in the outer cone ``gold bubble'' or in the region where the ablator and hohlraum material interact. The simulations provide guidance on which hohlraum mitigation methods will be most effective at improving inner beam propagation. Prepared by LLNL under Contract DE-AC52-07NA27344.

  13. Theoretical study of fabrication of line-and-space patterns with 7 nm quarter-pitch using electron beam lithography with chemically amplified resist process: III. Post exposure baking on quartz substrates

    NASA Astrophysics Data System (ADS)

    Kozawa, Takahiro

    2015-09-01

    Electron beam (EB) lithography is a key technology for the fabrication of photomasks for ArF immersion and extreme ultraviolet (EUV) lithography and molds for nanoimprint lithography. In this study, the temporal change in the chemical gradient of line-and-space patterns with a 7 nm quarter-pitch (7 nm space width and 21 nm line width) was calculated until it became constant, independently of postexposure baking (PEB) time, to clarify the feasibility of single nano patterning on quartz substrates using EB lithography with chemically amplified resist processes. When the quencher diffusion constant is the same as the acid diffusion constant, the maximum chemical gradient of the line-and-space pattern with a 7 nm quarter-pitch did not differ much from that with a 14 nm half-pitch under the condition described above. Also, from the viewpoint of process control, a low quencher diffusion constant is considered to be preferable for the fabrication of line-and-space patterns with a 7 nm quarter-pitch on quartz substrates.

  14. Thermographic calorimetry of the neutral beam injectors heating beams at TJ-II

    SciTech Connect

    Fuentes, C.; Liniers, M.; Guasp, J.; Doncel, J.; Botija, J.; Wolfers, G.; Alonso, J.; Acedo, M.; Sanchez, E.; Marcon, G.; Weber, M.; Carrasco, R.; Sarasola, X.; Zurro, B.; Tera, J.

    2006-10-15

    A new beam diagnostic based on infrared thermography has been developed for the neutral beam injectors of the stellarator TJ-II. A highly anisotropic movable target intercepts the beam at its entrance into the stellarator. The thermal print of the beam is captured with a high resolution infrared camera. The infrared images of the target can be translated, with the appropriate analysis, into power density patterns of the beam. The system is calibrated in situ with two thermocouples adiabatically mounted in the target. The two-dimensional beam power density distribution can be accurately characterized allowing beam optimization with respect to the different parameters involved in the beam formation and transport.

  15. Three-dimensional fabrication and characterisation of core-shell nano-columns using electron beam patterning of Ge-doped SiO{sub 2}

    SciTech Connect

    Gontard, Lionel C.; Jinschek, Joerg R.; Ou Haiyan; Verbeeck, Jo; Dunin-Borkowski, Rafal E.

    2012-06-25

    A focused electron beam in a scanning transmission electron microscope (STEM) is used to create arrays of core-shell structures in a specimen of amorphous SiO{sub 2} doped with Ge. The same electron microscope is then used to measure the changes that occurred in the specimen in three dimensions using electron tomography. The results show that transformations in insulators that have been subjected to intense irradiation using charged particles can be studied directly in three dimensions. The fabricated structures include core-shell nano-columns, sputtered regions, voids, and clusters.

  16. Sharp transition from ripple patterns to a flat surface for ion beam erosion of Si with simultaneous co-deposition of iron

    SciTech Connect

    Zhang, K.; Broetzmann, M.; Hofsaess, H.

    2012-09-15

    We investigate pattern formation on Si by sputter erosion under simultaneous co-deposition of Fe atoms, both at off-normal incidence, as function of the Fe surface coverage. The patterns obtained for 5 keV Xe ion irradiation at 30 Degree-Sign incidence angle are analyzed with atomic force microscopy. Rutherford backscattering spectroscopy of the local steady state Fe content of the Fe-Si surface layer allows a quantitative correlation between pattern type and Fe coverage. With increasing Fe coverage the patterns change, starting from a flat surface at low coverage (< 2 Multiplication-Sign 10{sup 15} Fe/cm{sup 2}) over dot patterns (2-8 Multiplication-Sign 10{sup 15} Fe/cm{sup 2}), ripples patterns (8-17 Multiplication-Sign 10{sup 15} Fe/cm{sup 2}), pill bug structures (1.8 Multiplication-Sign 10{sup 16} Fe/cm{sup 2}) and a rather flat surface with randomly distributed weak pits at high Fe coverage (>1.8 Multiplication-Sign 10{sup 16} Fe/cm{sup 2}). Our results confirm the observations by Macko et al. for 2 keV Kr ion irradiation of Si with Fe co-deposition. In particular, we also find a sharp transition from pronounced ripple patterns with large amplitude (rms roughness {approx} 18 nm) to a rather flat surface (rms roughness {approx} 0.5 nm). Within this transition regime, we also observe the formation of pill bug structures, i.e. individual small hillocks with a rippled structure on an otherwise rather flat surface. The transition occurs within a very narrow regime of the steady state Fe surface coverage between 1.7 and 1.8 Multiplication-Sign 10{sup 16} Fe/cm{sup 2}, where the composition of the mixed Fe-Si surface layer of about 10 nm thickness reaches the stoichiometry of FeSi{sub 2}. Phase separation towards amorphous iron silicide is assumed as the major contribution for the pattern formation at lower Fe coverage and the sharp transition from ripple patterns to a flat surface.

  17. Characterization of electron-beam recorded microdomain patterns on the nonpolar surface of LiNbO3 crystal by nondestructive methods

    NASA Astrophysics Data System (ADS)

    Kokhanchik, L. S.; Gainutdinov, R. V.; Mishina, E. D.; Lavrov, S. D.; Volk, T. R.

    2014-10-01

    We report on characterization of the electron-beam fabricated planar domain gratings on the nonpolar (Y-) surface of LiNbO3 crystals performed with the use of AFM and confocal second harmonic generation (SHG) microscopy. The dependence of domain formation on the irradiation conditions was investigated. The relation of domain thicknesses to the electron penetration depth is experimentally proved. In particular, the possibility of controlling the thickness of planar domains by varying acceleration electron-beam voltages is demonstrated. The observed specificity of SHG is analyzed in the framework of the Kleinman-Boyd theory [G. D. Boyd and D. A. Kleinman, J. Appl. Phys. 39, 3597 (1968)] and Uesu approach [Kaneshiro et al., J. Appl. Phys. 104, 054112 (2008); Kaneshiro et al., J. Opt. Soc. Am. B 27, 888 (2010)] extended in our case to reflection geometry. The calculations performed predict the dependence of SHG conversion efficiency η on the domain thickness, which is in a qualitative agreement with the experiment. It is shown that planar domains on top of the nonpolar surface always enhance the value of η as compared with the bare surface.

  18. Particle-filled microporous materials

    DOEpatents

    McAllister, Jerome W.; Kinzer, Kevin E.; Mrozinski, James S.; Johnson, Eric J.

    1992-07-14

    A microporous particulate-filled thermoplastic polymeric article is provided. The article can be in the form of a film, a fiber, or a tube. The article has a thermoplastic polymeric structure having a plurality of interconnected passageways to provide a network of communicating pores. The microporous structure contains discrete submicron or low micron-sized particulate filler, the particulate filler being substantially non-agglomerated.

  19. Particle-filled microporous materials

    DOEpatents

    McAllister, Jerome W.; Kinzer, Kevin E.; Mrozinski, James S.; Johnson, Eric J.; Dyrud, James F.

    1990-01-01

    A microporous particulate-filled thermoplastic polymeric article is provided. The article can be in the form of a film, a fiber, or a tube. The article has a thermoplastic polymeric structure having a plurality of interconnected passageways to provide a network of communicating pores. The microporous structure contains discrete submicron or low micron-sized particulate filler, the particulate filler being substantially non-agglomerated.

  20. Particle-filled microporous materials

    DOEpatents

    McAllister, J.W.; Kinzer, K.E.; Mrozinski, J.S.; Johnson, E.J.; Dyrud, J.F.

    1990-09-18

    A microporous particulate-filled thermoplastic polymeric article is provided. The article can be in the form of a film, a fiber, or a tube. The article has a thermoplastic polymeric structure having a plurality of interconnected passageways to provide a network of communicating pores. The microporous structure contains discrete submicron or low micron-sized particulate filler, the particulate filler being substantially non-agglomerated. 3 figs.

  1. Safety in Royal Filling Factories

    DTIC Science & Technology

    1950-10-01

    factories and certain special trials were staged to ascertain effect of explosion on underground Magazines. (See C.S.A.R*s report, Glascoed trials). On...spacing were the result of long experience of the effects of explosions in filling, and incidentally resulted in a considerable economy in cost of...etc (9) Any ignition is quenched in its initial stages and/or an explosive effect kept to a minimum. (10) Operatives are made fully aware of the

  2. Exhaustive search system and method using space-filling curves

    DOEpatents

    Spires, Shannon V.

    2003-10-21

    A search system and method for one agent or for multiple agents using a space-filling curve provides a way to control one or more agents to cover an area of any space of any dimensionality using an exhaustive search pattern. An example of the space-filling curve is a Hilbert curve. The search area can be a physical geography, a cyberspace search area, or an area searchable by computing resources. The search agent can be one or more physical agents, such as a robot, and can be software agents for searching cyberspace.

  3. Commissioning results of the narrow-band beam position monitor system upgrade in the APS storage ring.

    SciTech Connect

    Singh, O.

    1999-04-20

    When using a low emittance storage ring as a high brightness synchrotron radiation source, it is critical to maintain a very high degree of orbit stability, both for the short term and for the duration of an operational fill. A fill-to-fill reproducibility is an additional important requirement. Recent developments in orbit correction algorithms have provided tools that are capable of achieving a high degree of orbit stability. However, the performance of these feedback systems can be severely limited if there are errors in the beam position monitors (BPMs). The present orbit measurement and correction system at the APS storage ring utilizes 360 broad-band-type BPMs that provide turn-by-turn diagnostics and an ultra-stable orbit: < 1.8 micron rms vertically and 4.5 microns rms horizontally in a frequency band of 0.017 to 30 Hz. The effects of beam intensity and bunch pattern dependency on these BPMs have been significantly reduced by employing offset compensation correction. Recently, 40 narrow-band switching-type BPMs have been installed in the APS storage ring, two in each of 20 operational insertion device straight sections, bringing the total number of beam position monitors to 400. The use of narrow-band BPM electronics is expected to reduce sensitivity to beam intensity, bunch pattern dependence, and long-term drift. These beam position monitors are used for orbit correction/feedback and machine protection interlocks for the insertion device beamlines. The commissioning results and overall performance for orbit stability are provided.

  4. Beam diagnostics

    SciTech Connect

    Bogaty, J.; Clifft, B.E.; Zinkann, G.P.; Pardo, R.C.

    1995-08-01

    The ECR-PII injector beam line is operated at a fixed ion velocity. The platform high voltage is chosen so that all ions have a velocity of 0.0085c at the PII entrance. If a previous tune configuration for the linac is to be used, the beam arrival time must be matched to the previous tune as well. A nondestructive beam-phase pickup detector was developed and installed at the entrance to the PII linac. This device provides continuous phase and beam current information and allows quick optimization of the beam injected into PII. Bunches traverse a short tubular electrode thereby inducing displacement currents. These currents are brought outside the vacuum interface where a lumped inductance resonates electrode capacitance at one of the bunching harmonic frequencies. This configuration yields a basic sensitivity of a few hundred millivolts signal per microampere of beam current. Beam-induced radiofrequency signals are summed against an offset frequency generated by our master oscillator. The resulting kilohertz difference frequency conveys beam intensity and bunch phase information which is sent to separate processing channels. One channel utilizes a phase locked loop which stabilizes phase readings if beam is unstable. The other channel uses a linear full wave active rectifier circuit which converts kilohertz sine wave signal amplitude to a D.C. voltage representing beam current. A prototype set of electronics is now in use with the detector and we began to use the system in operation to set the arrival beam phase. A permanent version of the electronics system for the phase detector is now under construction. Additional nondestructive beam intensity and phase monitors at the {open_quotes}Booster{close_quotes} and {open_quotes}ATLAS{close_quotes} linac sections are planned as well as on some of the high-energy beam lines. Such a monitor will be particularly useful for FMA experiments where the primary beam hits one of the electric deflector plates.

  5. Pattern of filling in the pulmonary capillary bed.

    NASA Technical Reports Server (NTRS)

    Warrell, D. A.; Evans, J. W.; Clarke, R. O.; Kingaby, G. P.; West, J. B.

    1972-01-01

    Artificially ventilated and perfused dog lungs were rapidly frozen under various physiological conditions. In 2-micron-thick sections the number of red blood cells (RBCs) per 10-micron length of alveolar septum was counted. Under conditions in which alveolar pressure exceeded venous pressure, variation in RBC concentration within areas supplied by single arterioles accounted completely for variation between areas supplied by different arterioles. Except at very high perfusion pressures when venous pressure exceeded alveolar pressure, there was no significant correlation between RBC concentrations of pairs of adjacent septa.

  6. Asymmetric acoustic transmission in graded beam

    NASA Astrophysics Data System (ADS)

    Jing, Li; Wu, Jiu Hui; Guan, Dong; Lu, Kuan; Gao, Nansha; Songhua, Cao

    2016-12-01

    We demonstrate the dynamic effective material parameters and vibration performance of a graded beam. The structure of the beam was composed of several unit cells with different fill factors. The dispersion relations and energy band structures of each unit cell were calculated using the finite element method (FEM). The dynamic effective material parameters in each unit cell of the graded beam were determined by the dispersion relations and energy band structures. Longitudinal wave propagation was investigated using a numerical method and FEM. The results show that the graded beam allows asymmetric acoustic transmission over a wide range of frequencies.

  7. Quantitation of IgE and carcinoembryonic antigen (CEA) by optical beam deflection (OBD) measurement of dot-immunobinding assay patterns visualized by an ELISA technique.

    PubMed

    Matsuzawa, S; Kimura, H; Tu, C Y; Kitamori, T; Sawada, T

    1993-05-05

    Dot-immunobinding assays of IgE and CEA were performed by a conventional dot-ELISA technique with diaminobenzidine staining, and the quantitative results were compared by densitometry and a new, spectroscopic, optical beam deflection (OBD) method using the same membrane. It was possible with the OBD method to detect quantities of these substances at least ten times smaller than with densitometry. Better intra-assay reproducibility for IgE and CEA measurements was obtained by the OBD method. The measurable ranges of the OBD method was broader than that of densitometry, because dark bands caused OBD in proportion to their color densities. When the dot-immunobinding assay with OBD measurement for CEA was also compared with a microtube ELISA using biotin-avidin conjugates, the sensitivities and reproducibilities of the two methods were found to be similar, with a correlation coefficient of 0.991.

  8. Mold filling and microhardness of 1% Fe titanium alloys.

    PubMed

    Sato, Hideki; Komatsu, Masashi; Miller, Barbara; Shimizu, Hiroshi; Fujii, Hideki; Okabe, Toru

    2004-06-01

    We examined the mold filling capacity and microhardness of two industrial 1% Fe titanium alloys: Super-TIX800 (Nippon Steel Corp.) (Fe: 0.910%, O: 0.370%, N: 0.005%) and Super-TIX800N (Nippon Steel Corp.) (Fe: 0.960%, O: 0.300%, N: 0.041%). Two wedge-shaped acrylic patterns (with 30 degrees or 15 degrees angles) were prepared. Each alloy was cast in a centrifugal casting machine. Mold filling was evaluated as the missing length between the tip of the casting and the theoretical tip. Vickers hardness of the edge of the castings was also determined. For both angles tested, there were no significant differences (p>0.05) in mold filling among these alloys and the control (CP Ti). The results of testing the microhardness near the cast surfaces indicated that the hardened reaction layers on these alloys were thinner at the edge compared to CP Ti.

  9. Fluid-filled dynamic bowtie filter: a feasibility study

    NASA Astrophysics Data System (ADS)

    Shunhavanich, Picha; Hsieh, Scott S.; Pelc, Norbert J.

    2015-03-01

    By varying its thickness to compensate for the different path length through the patient as a function of fan angle, a pre-patient bowtie filter modulates flux distribution to reduce patient dose, scatter, and detector dynamic range, and to improve image quality. A dynamic bowtie filter is superior to its traditional, static counterpart in its ability to adjust its thickness along different fan and view angles to suit a specific patient and task. Among the proposed dynamic bowtie designs, the piecewise-linear and the digital beam attenuators offer more flexibility than conventional filters, but rely on analog positioning of a limited number of wedges. In this work, we introduce a new approach with digital control, called the fluid-filled dynamic bowtie filter. It is a two-dimensional array of small binary elements (channels filled or unfilled with attenuating liquid) in which the cumulative thickness along the x-ray path contributes to the bowtie's total attenuation. Using simulated data from a pelvic scan, the performance is compared with the piecewise-linear attenuator. The fluid-filled design better matches the desired target attenuation profile and delivers a 4.2x reduction in dynamic range. The variance of the reconstruction (or noise map) can also be more homogeneous. In minimizing peak variance, the fluid-filled attenuator shows a 3% improvement. From the initial simulation results, the proposed design has more control over the flux distribution as a function of both fan and view angles.

  10. Spall Fracture Patterns for the Heterophase Cu-Al-Ni Alloy in Ultrafine- and Coarse-Grained States Exposed to a Nanosecond Relativistic High-Current Electron Beam

    NASA Astrophysics Data System (ADS)

    Dudarev, E. F.; Markov, A. B.; Mayer, A. E.; Bakach, G. P.; Tabachenko, A. N.; Kashin, O. A.; Pochivalova, G. P.; Skosyrskii, A. B.; Kitsanov, S. A.; Zhorovkov, M. F.; Yakovlev, E. V.

    2013-05-01

    A comparative study of spall fracture patterns for the heterophase Cu - 8.45% Al - 5.06% Ni alloy (аt.%) in ultrafine- and coarse-grained states under shock-wave loading using the "SINUS-7" electron accelerator is carried out. For electron energy of 1.4 MeV, pulse duration of 50 ns, and power density of 1.6·1010 W/cm2, the shock wave amplitude was 8 GPa and the strain rate was ~2·105 s-1. It is established that the thickness of the spalled layer increased for both grained structures, and the degree of plastic strain decreased with increasing target thickness. Based on experimental data obtained and results of theoretical calculations, it is demonstrated that the spall strength of ultrafine- and coarse-grained structures is ~3 GPa. The data on the grained structure at different distances from the spall surface and spall fraction patterns and mechanism are presented.

  11. Influence of grid control on beam quality in laser ion source generating high-current low-charged copper ions

    SciTech Connect

    Hasegawa, J.; Yoshida, M.; Ogawa, M.; Oguri, Y.; Nakajima, M.; Horioka, K.; Kwan, J.

    2003-08-01

    We examined grid-controlled extraction for a laser ion source using a KrF laser. By using grid-controlled extraction in the over-dense regime, we found that the ion beam current waveforms were stabilized more significantly as the grid bias raised from -90 V to -280 V. The normalized emittance of 0.08 {pi}mm-mrad measured without the grid control was improved to 0.06 {pi}mm-mrad with the grid control. In contrast to this observation, the grid bias disturbed the pattern of the beam extracted in the source-limited regime. Fast extraction was carried out using a high-voltage pulse with a rise time of {approx} 100 ns. The grid control suppressed successfully the beam pedestal originating from the plasma pre-filled in the extraction gap.

  12. Groundwater Nitrate Removal Capacity of Filled Salt Marshes

    NASA Astrophysics Data System (ADS)

    Addy, K.; Gold, A. J.; Stolt, M. H.; Groffman, P. M.

    2006-05-01

    at undisturbed salt marshes. We hypothesize that the buried salt marshes are still capable of contributing carbon to fuel groundwater denitrification, but site disturbance appears to alter the spatial pattern of groundwater denitrification capacity. Additionally the longevity of the buried labile carbon pools is a source of uncertainty in evaluating the long-term nitrate sink function of filled salt marshes.

  13. Nano Josephson superconducting tunnel junctions in YBa2Cu3O(7-δ) directly patterned with a focused helium ion beam.

    PubMed

    Cybart, Shane A; Cho, E Y; Wong, T J; Wehlin, Björn H; Ma, Meng K; Huynh, Chuong; Dynes, R C

    2015-07-01

    Since the discovery of the high-transition-temperature superconductors (HTSs), researchers have explored many methods to fabricate superconducting tunnel junctions from these materials for basic science purposes and applications. HTS circuits operating at liquid-nitrogen temperatures (∼77 K) would significantly reduce power requirements in comparison with those fabricated from conventional superconductors. The difficulty is that the superconducting coherence length is very short and anisotropic in these materials, typically ∼2 nm in the a-b plane and ∼0.2 nm along the c axis. The electrical properties of Josephson junctions are therefore sensitive to chemical variations and structural defects on atomic length scales. To make multiple uniform HTS junctions, control at the atomic level is required. In this Letter we demonstrate all-HTS Josephson superconducting tunnel junctions created by using a 500-pm-diameter focused beam of helium ions to directly write tunnel barriers into YBa2Cu3O(7-δ) (YBCO) thin films. We demonstrate the ability to control the barrier properties continuously from conducting to insulating by varying the irradiation dose. This technique could provide a reliable and reproducible pathway for scaling up quantum-mechanical circuits operating at liquid-nitrogen temperatures, as well as an avenue to conduct novel planar superconducting tunnelling studies for basic science.

  14. Nano Josephson superconducting tunnel junctions in YBa2Cu3O7-δ directly patterned with a focused helium ion beam

    NASA Astrophysics Data System (ADS)

    Cybart, Shane A.; Cho, E. Y.; Wong, T. J.; Wehlin, Björn H.; Ma, Meng K.; Huynh, Chuong; Dynes, R. C.

    2015-07-01

    Since the discovery of the high-transition-temperature superconductors (HTSs), researchers have explored many methods to fabricate superconducting tunnel junctions from these materials for basic science purposes and applications. HTS circuits operating at liquid-nitrogen temperatures (˜77 K) would significantly reduce power requirements in comparison with those fabricated from conventional superconductors. The difficulty is that the superconducting coherence length is very short and anisotropic in these materials, typically ˜2 nm in the a-b plane and ˜0.2 nm along the c axis. The electrical properties of Josephson junctions are therefore sensitive to chemical variations and structural defects on atomic length scales1. To make multiple uniform HTS junctions, control at the atomic level is required. In this Letter we demonstrate all-HTS Josephson superconducting tunnel junctions created by using a 500-pm-diameter focused beam of helium ions to directly write tunnel barriers into YBa2Cu3O7-δ (YBCO) thin films. We demonstrate the ability to control the barrier properties continuously from conducting to insulating by varying the irradiation dose. This technique could provide a reliable and reproducible pathway for scaling up quantum-mechanical circuits operating at liquid-nitrogen temperatures, as well as an avenue to conduct novel planar superconducting tunnelling studies for basic science.

  15. Resistively shunted YBa2Cu3O7 grain boundary junctions and low-noise SQUIDs patterned by a focused ion beam down to 80 nm linewidth

    NASA Astrophysics Data System (ADS)

    Nagel, J.; Konovalenko, K. B.; Kemmler, M.; Turad, M.; Werner, R.; Kleisz, E.; Menzel, S.; Klingeler, R.; Büchner, B.; Kleiner, R.; Koelle, D.

    2011-01-01

    YBa2Cu3O7 24° (30°) bicrystal grain boundary junctions (GBJs), shunted with 60 nm (20 nm) thick Au, were fabricated by focused ion beam milling with widths 80 nm <= w <= 7.8 µm. At 4.2 K we find critical current densities jc in the 105 A cm - 2 range (without a clear dependence on w) and an increase in resistance times junction area ρn with an approximate scaling \\rho_n\\propto w^{1/2} . For the narrowest GBJs jcρn = IcRn≈100 µV (with critical current Ic and junction resistance Rn), which is promising for the realization of sensitive nanoSQUIDs for the detection of small spin systems. We demonstrate that our fabrication process allows the realization of sensitive nanoscale dc SQUIDs; for a SQUID with w≈100 nm wide GBJs we find an rms magnetic flux noise spectral density of SΦ1/2≈4 μΦ0 Hz - 1/2 in the white noise limit. We also derive an expression for the spin sensitivity Sμ1/2, which depends on SΦ1/2, on the location and orientation of the magnetic moment of a magnetic particle to be detected by the SQUID, and on the SQUID geometry. For the unoptimized SQUIDs presented here, we estimate Sμ1/2 = 390 μB Hz - 1/2, which could be further improved by at least an order of magnitude.

  16. Analysis of beam loss induced abort kicker instability

    SciTech Connect

    Zhang W.; Sandberg, J.; Ahrens, L.; Fischer, W.; Hahn, H.; Mi, J.; Pai, C.; Tan, Y.

    2012-05-20

    Through more than a decade of operation, we have noticed the phenomena of beam loss induced kicker instability in the RHIC beam abort systems. In this study, we analyze the short term beam loss before abort kicker pre-fire events and operation conditions before capacitor failures. Beam loss has caused capacitor failures and elevated radiation level concentrated at failed end of capacitor has been observed. We are interested in beam loss induced radiation and heat dissipation in large oil filled capacitors and beam triggered thyratron conduction. We hope the analysis result would lead to better protection of the abort systems and improved stability of the RHIC operation.

  17. Filling of carbon nanotubes and nanofibres

    PubMed Central

    Gately, Reece D

    2015-01-01

    Summary The reliable production of carbon nanotubes and nanofibres is a relatively new development, and due to their unique structure, there has been much interest in filling their hollow interiors. In this review, we provide an overview of the most common approaches for filling these carbon nanostructures. We highlight that filled carbon nanostructures are an emerging material for biomedical applications. PMID:25821693

  18. 7 CFR 58.923 - Filling containers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Filling containers. 58.923 Section 58.923 Agriculture... Procedures § 58.923 Filling containers. (a) The filling of small containers with product shall be done in a sanitary manner. The containers shall not contaminate or detract from the quality of the product in any...

  19. A pencil beam algorithm for helium ion beam therapy

    SciTech Connect

    Fuchs, Hermann; Stroebele, Julia; Schreiner, Thomas; Hirtl, Albert; Georg, Dietmar

    2012-11-15

    Purpose: To develop a flexible pencil beam algorithm for helium ion beam therapy. Dose distributions were calculated using the newly developed pencil beam algorithm and validated using Monte Carlo (MC) methods. Methods: The algorithm was based on the established theory of fluence weighted elemental pencil beam (PB) kernels. Using a new real-time splitting approach, a minimization routine selects the optimal shape for each sub-beam. Dose depositions along the beam path were determined using a look-up table (LUT). Data for LUT generation were derived from MC simulations in water using GATE 6.1. For materials other than water, dose depositions were calculated by the algorithm using water-equivalent depth scaling. Lateral beam spreading caused by multiple scattering has been accounted for by implementing a non-local scattering formula developed by Gottschalk. A new nuclear correction was modelled using a Voigt function and implemented by a LUT approach. Validation simulations have been performed using a phantom filled with homogeneous materials or heterogeneous slabs of up to 3 cm. The beams were incident perpendicular to the phantoms surface with initial particle energies ranging from 50 to 250 MeV/A with a total number of 10{sup 7} ions per beam. For comparison a special evaluation software was developed calculating the gamma indices for dose distributions. Results: In homogeneous phantoms, maximum range deviations between PB and MC of less than 1.1% and differences in the width of the distal energy falloff of the Bragg-Peak from 80% to 20% of less than 0.1 mm were found. Heterogeneous phantoms using layered slabs satisfied a {gamma}-index criterion of 2%/2mm of the local value except for some single voxels. For more complex phantoms using laterally arranged bone-air slabs, the {gamma}-index criterion was exceeded in some areas giving a maximum {gamma}-index of 1.75 and 4.9% of the voxels showed {gamma}-index values larger than one. The calculation precision of the

  20. Gaussian Filtering with Tapered Oil-Filled Photonic Bandgap Fibers

    NASA Astrophysics Data System (ADS)

    Brunetti, A. C.; Scolari, L.; Weirich, J.; Eskildsen, L.; Bellanca, G.; Bassi, P.; Bjarklev, A.

    2008-10-01

    A tunable Gaussian filter based on a tapered oil-filled photonic crystal fiber is demonstrated. The filter is centered at λ = 1364 nm with a bandwidth (FWHM) of 237nm. Tunability is achieved by changing the temperature of the filter. A shift of 210nm of the central wavelength has been observed by increasing the temperature from 25 °C to 100 °C. The measurements are compared to a simulated spectrum obtained by means of a vectorial Beam Propagation Method model.

  1. Two variants of minimum discarded fill ordering

    SciTech Connect

    D'Azevedo, E.F. ); Forsyth, P.A.; Tang, Wei-Pai . Dept. of Computer Science)

    1991-01-01

    It is well known that the ordering of the unknowns can have a significant effect on the convergence of Preconditioned Conjugate Gradient (PCG) methods. There has been considerable experimental work on the effects of ordering for regular finite difference problems. In many cases, good results have been obtained with preconditioners based on diagonal, spiral or natural row orderings. However, for finite element problems having unstructured grids or grids generated by a local refinement approach, it is difficult to define many of the orderings for more regular problems. A recently proposed Minimum Discarded Fill (MDF) ordering technique is effective in finding high quality Incomplete LU (ILU) preconditioners, especially for problems arising from unstructured finite element grids. Testing indicates this algorithm can identify a rather complicated physical structure in an anisotropic problem and orders the unknowns in the preferred'' direction. The MDF technique may be viewed as the numerical analogue of the minimum deficiency algorithm in sparse matrix technology. At any stage of the partial elimination, the MDF technique chooses the next pivot node so as to minimize the amount of discarded fill. In this work, two efficient variants of the MDF technique are explored to produce cost-effective high-order ILU preconditioners. The Threshold MDF orderings combine MDF ideas with drop tolerance techniques to identify the sparsity pattern in the ILU preconditioners. These techniques identify an ordering that encourages fast decay of the entries in the ILU factorization. The Minimum Update Matrix (MUM) ordering technique is a simplification of the MDF ordering and is closely related to the minimum degree algorithm. The MUM ordering is especially for large problems arising from Navier-Stokes problems. Some interesting pictures of the orderings are presented using a visualization tool. 22 refs., 4 figs., 7 tabs.

  2. Use of beam deflection to control an electron beam wire deposition process

    NASA Technical Reports Server (NTRS)

    Taminger, Karen M. (Inventor); Hofmeister, William H. (Inventor); Hafley, Robert A. (Inventor)

    2013-01-01

    A method for controlling an electron beam process wherein a wire is melted and deposited on a substrate as a molten pool comprises generating the electron beam with a complex raster pattern, and directing the beam onto an outer surface of the wire to thereby control a location of the wire with respect to the molten pool. Directing the beam selectively heats the outer surface of the wire and maintains the position of the wire with respect to the molten pool. An apparatus for controlling an electron beam process includes a beam gun adapted for generating the electron beam, and a controller adapted for providing the electron beam with a complex raster pattern and for directing the electron beam onto an outer surface of the wire to control a location of the wire with respect to the molten pool.

  3. Stable Vortex Generation in Liquid Filled Wells by Mode Conversion of Surface Acoustic Waves

    NASA Astrophysics Data System (ADS)

    Landskron, Johannes; Schmidt, Katrin; Kufner, Maria; Lindner, Gerhard

    The formation of stable vortex flow pattern has been observed at liquid filled aluminum wells of 15 to 30 mm diameter when Lamb waves are excited on the bottom of the wells by piezoelectric transducers operated at a frequency of 1 MHz. The shape of the vortex pattern changed with the position of the transducer. Strong differences in mixing times were observed between water and ethanol when the filling level was changed and a remarkable reduction of mixing time was achieved by the addition of a small amount of detergent to water at small filling levels. Besides mixing of liquids thermal equilibration within a liquid volume was accelerated by acoustic streaming.

  4. Method and apparatus for efficient photodetachment and purification of negative ion beams

    DOEpatents

    Beene, James R [Oak Ridge, TN; Liu, Yuan [Knoxville, TN; Havener, Charles C [Knoxville, TN

    2008-02-26

    Methods and apparatus are described for efficient photodetachment and purification of negative ion beams. A method of purifying an ion beam includes: inputting the ion beam into a gas-filled multipole ion guide, the ion beam including a plurality of ions; increasing a laser-ion interaction time by collisional cooling the plurality of ions using the gas-filled multipole ion guide, the plurality of ions including at least one contaminant; and suppressing the at least one contaminant by selectively removing the at least one contaminant from the ion beam by electron photodetaching at least a portion of the at least one contaminant using a laser beam.

  5. Beam-energy inequality in the beam-beam interaction

    SciTech Connect

    Krishnagopal, S.; Siemann, R. )

    1990-03-01

    Conditions for energy transparency,'' unequal-energy beams having the same beam-beam behavior, are derived for round beams from a Hamiltonian model of the beam-beam interaction. These conditions are equal fractional betatron tunes, equal synchrotron tunes, equal beam-beam strength parameters, equal nominal sizes, equal {beta}{sup *}'s and equal bunch lengths. With these conditions the only way to compensate for unequal energies is with the number of particles per bunch.

  6. Gap-filling strategies for annual VOC flux data sets.

    PubMed

    Bamberger, I; Hörtnagl, L; Walser, M; Hansel, A; Wohlfahrt, G

    2013-11-01

    Up to now the limited knowledge about the exchange of volatile organic compounds (VOCs) between the biosphere and the atmosphere is one of the factors which hinders more accurate climate predictions. Complete long-term flux data sets of several VOCs to quantify the annual exchange and validate recent VOC models are basically not available. In combination with long-term VOC flux measurements the application of gap-filling routines is inevitable in order to replace missing data and make an important step towards a better understanding of the VOC ecosystem-atmosphere exchange on longer time scales. We performed VOC flux measurements above a mountain meadow in Austria during two complete growing seasons (from snowmelt in spring to snow reestablishment in late autumn) and used this data set to test the performance of four different gap-filling routines, mean diurnal variation (MDV), mean gliding window (MGW), look up tables (LUT) and linear interpolation (LIP), in terms of their ability to replace missing flux data in order to obtain reliable VOC sums. According to our findings the MDV routine was outstanding with regard to the minimization of the gap-filling error for both years and all quantified VOCs. The other gap-filling routines, which performed gap-filling on 24 h average values, introduced considerably larger uncertainties. The error which was introduced by the application of the different filling routines increased linearly with the number of data gaps. Although average VOC fluxes measured during the winter period (complete snow coverage) were close to zero, these were highly variable and the filling of the winter period resulted in considerably higher uncertainties compared to the application of gap-filling during the measurement period. The annual patterns of the overall cumulative fluxes for the quantified VOCs showed a completely different behavior in 2009, which was an exceptional year due to the occurrence of a severe hailstorm, compared to 2011. Methanol

  7. Exploring transverse pattern formation in a dual-polarization self-mode-locked monolithic Yb: KGW laser and generating a 25-GHz sub-picosecond vortex beam via gain competition.

    PubMed

    Chang, M T; Liang, H C; Su, K W; Chen, Y F

    2016-04-18

    Formation of transverse modes in a dual-polarization self-mode-locked monolithic Yb: KGW laser under high-power pumping is thoroughly explored. It is experimentally observed that the polarization-resolved transverse patterns are considerably affected by the pump location in the transverse plane of the gain medium. In contrast, the longitudinal self-mode-locking is nearly undisturbed by the pump position, even under the high-power pumping. Under central pumping, a vortex beam of the Laguerre-Gaussian LGp,l mode with p = 1 and l = 1 can be efficiently generated through the process of the gain competition with a sub-picosecond pulse train at 25.3 GHz and the output power can be up to 1.45 W at a pump power of 10.0 W. Under off-center pumping, the symmetry breaking causes the transverse patterns to be dominated by the high-order Hermite-Gaussian modes. Numerical analyses are further performed to manifest the symmetry breaking induced by the off-center pumping.

  8. Defect-enhanced void filling and novel filled phases of open-structure skutterudites

    DOE PAGES

    Xi, Lili; Qiu, Yuting; Shi, Xun; ...

    2015-05-14

    Here, we report the design of novel filled CoSb3 skutterudite phases based on a combination of filling and Sb-substituted Ga/In defects. Ga/In doped skutterudite phases with Li-, Nd-, and Sm-fillings can be formed via this strategy, which can have relatively wider ranges of carrier concentration than other conventional filled skutterudite phases.

  9. 30 CFR 816.72 - Disposal of excess spoil: Valley fills/head-of-hollow fills.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... incorporated into the design and construction of the fill as follows. (1) The fill shall have, along the... spoil fill and from seeps and springs in the foundation of the disposal area. Rocks used in the rock... maintained at the head of the fill during and after construction, to intercept surface runoff and...

  10. Defect-enhanced void filling and novel filled phases of open-structure skutterudites

    SciTech Connect

    Xi, Lili; Qiu, Yuting; Shi, Xun; Zhang, Wenqing; Chen, Lidong; Singh, David J.; Yang, Jihui

    2015-05-14

    Here, we report the design of novel filled CoSb3 skutterudite phases based on a combination of filling and Sb-substituted Ga/In defects. Ga/In doped skutterudite phases with Li-, Nd-, and Sm-fillings can be formed via this strategy, which can have relatively wider ranges of carrier concentration than other conventional filled skutterudite phases.

  11. Beam tuning

    SciTech Connect

    Pardo, R.C.; Zinkann, G.P.

    1995-08-01

    A program for configuring the linac, based on previously run configurations for any desired beam was used during the past year. This program uses only a small number of empirical tunes to scale resonator fields to properly accelerate a beam with a different charge-to-mass (q/A) ratio from the original tune configuration. The program worked very well for the PII linac section where we can easily match a new beam`s arrival phase and velocity to the tuned value. It was also fairly successful for the Booster and ATLAS sections of the linac, but not as successful as for the PII linac. Most of the problems are associated with setting the beam arrival time correctly for each major linac section. This problem is being addressed with the development of the capacitive pickup beam phase monitor discussed above. During the next year we expect to improve our ability to quickly configure the linac for new beams and reduce the time required for linac tuning. Already the time required for linac tuning as a percentage of research hours has decreased from 22% in FY 1993 to 15% in the first quarter of FY 1995.

  12. Vehicle type affects filling of fractional laser-ablated channels imaged by optical coherence tomography.

    PubMed

    Olesen, Uffe Høgh; Mogensen, Mette; Haedersdal, Merete

    2017-04-01

    Ablative fractional laser (AFXL) is an emerging method that enhances topical drug delivery. Penetrating the skin in microscopic, vertical channels, termed microscopic treatment zones (MTZs), the fractional technique circumvents the skin barrier and allows increased uptake of topically applied drugs. This study aims to elucidate the impact of vehicle type on the filling of MTZs from application of liquid, gel, and cream vehicles. Ex vivo pig skin was exposed to 10,600 nm fractional CO2 laser at 5% density, 120 μm beam diameter, and fluences of 40 and 80 mJ/microbeam (mJ/mb). Six repetitions were performed for each of six interventions (2 fluences and 3 vehicle types, n = 36). MTZ dimensions and filling by vehicle type were evaluated by optical coherence tomography, using blue tissue dye as a contrast-enhancing agent. Outcome measure was degree of MTZ filling assessed as percentages of empty, partially filled, and completely filled MTZs (108-127 MTZs/intervention analyzed) and evaluated statistically using Kruskal-Wallis and Dunn's tests. MTZs reached mid-dermal levels of 225 μm (40 mJ/mb) and 375 μm (80 mJ/mb) penetration depths (p < 0.0001). Filling of MTZs depended on type of applied vehicle. At 80 mJ/mb, liquid (67% completely filled, p < 0.01) and gel (60%, p < 0.05) formulations filled MTZs significantly better than cream formulation (31%). At 40 mJ/mb, liquid and gel formulations filled 90% (p < 0.05) and 77% (p > 0.05) of MTZs completely versus 55% for cream formulation. Thus, filling was overall greater for more superficial MTZs. In conclusion, vehicle type affects filling of MTZs, which may be of importance for AFXL-assisted drug delivery.

  13. Characterization of a liquid-filled turbulence simulator

    NASA Astrophysics Data System (ADS)

    Davis, Christopher C.; Zhang, Yimin; Plett, Mark L.; Polak-Dingels, Penelope; Barbier, Pierre R.; Rush, David W.

    1998-10-01

    The development of high performance line-of-sight optical communication links through the turbulent atmosphere is facilitated by laboratory tests of schemes involving adaptive optics, beam tracking, modulation and coding, aperture averaging, fading statistics, and transmitter/receiver diversity. A water-filled turbulence tube has been implemented to simulate, in some respects, the effects produced on a laser beam when it propagates several kilometers through the air. This tube is being used to investigate on a laboratory scale: aperture averaging, fluctuation statistics, optical path difference, high data rate modulation, and various coding schemes. The liquid- filled turbulence tube causes fluctuations on a slower time scale than does the atmosphere. At low turbulence levels it produces log-normal fluctuation statistics, causes tip-tilt errors similar to those previously observed for atmospheric paths, and has already allowed evaluation of aperture averaging and fade statistics. It also allows the testing of various technological schemes to deal with atmospheric turbulence effects without any specific assumptions, such as weak Kolmogorov turbulence, being built into the model.

  14. Foldable beam

    NASA Technical Reports Server (NTRS)

    Hedgepeth, J. M.; Coyner, J. V.; Crawford, R. F.

    1981-01-01

    A foldable beam possessing superior qualities of light weight, compactness for transportation, quick deployment with minimum use of force, and high strength is described. These qualities are achieved through the use of a series of longitudinally rigid segments, hinged along one side and threaded by one or two cables along the opposite side. Tightening the cables holds the beam extended. Loosening the cables permits the segments to fold away from the threaded side. In one embodiment the segments are connected by canted hinges with the result that the beam may be folded in a helix-like configuration around a cylinder. In another embodiment the segments themselves may be hinged to fold flat laterally as the beam is folded, resulting in a configuration that may be helixed around a shorter cylinder.

  15. Beam-beam deflection and signature curves for elliptic beams

    SciTech Connect

    Ziemann, V.

    1990-10-22

    In this note we will present closed expressions for the beam-beam deflection angle for arbitrary elliptic beams including tilt. From these expressions signature curves, i.e., systematic deviations from the round beam deflection curve due to ellipticity or tilt are derived. In the course of the presentation we will prove that it is generally impossible to infer individual beam sizes from beam-beam deflection scans. 3 refs., 2 figs.

  16. Electron beam inspection methods for imprint lithography at 32 nm

    NASA Astrophysics Data System (ADS)

    Selinidis, Kosta; Thompson, Ecron; Sreenivasan, S. V.; Resnick, Douglas J.

    2009-01-01

    Step and Flash Imprint Lithography redefines nanoimprinting. This novel technique involves the field-by-field deposition and exposure of a low viscosity resist deposited by jetting technology onto the substrate. The patterned mask is lowered into the fluid which then quickly flows into the relief patterns in the mask by capillary action. Following this filling step, the resist is crosslinked under UV radiation, and then the mask is removed leaving a patterned solid on the substrate. Compatibility with existing CMOS processes requires a mask infrastructure in which resolution, inspection and repair are all addressed. The purpose of this paper is to understand the limitations of inspection at half pitches of 32 nm and below. A 32 nm programmed defect mask was fabricated. Patterns included in the mask consisted of an SRAM Metal 1 cell, dense lines, and dense arrays of pillars. Programmed defect sizes started at 4 nm and increased to 48 nm in increments of 4 nm. Defects in both the mask and imprinted wafers were characterized scanning electron microscopy and the measured defect areas were calculated. These defects were then inspected using a KLA-T eS35 electron beam wafer inspection system. Defect sizes as small as 12 nm were detected, and detection limits were found to be a function of defect type.

  17. Second-order temporal interference of two independent light beams at an asymmetrical beam splitter

    NASA Astrophysics Data System (ADS)

    Liu, Jianbin; Wang, Jingjing; Xu, Zhuo

    2017-01-01

    The second-order temporal interference of classical and nonclassical light at an asymmetrical beam splitter is discussed based on two-photon interference in Feynman's path integral theory. The visibility of the second-order interference pattern is determined by the properties of the superposed light beams, the ratio between the intensities of these two light beams, and the reflectivity of the asymmetrical beam splitter. Some requirements about the asymmetrical beam splitter have to be satisfied in order to ensure that the visibility of the second-order interference pattern of nonclassical light beams exceeds classical limit. The visibility of the second-order interference pattern of photons emitted by two independent single-photon sources is independent of the ratio between the intensities. These conclusions are important for the researches and applications in quantum optics and quantum information when asymmetrical beam splitter is employed.

  18. Classification of munition fill using laser acoustics

    SciTech Connect

    Rodriguez, J.G.; Blackwood, L.G.

    1997-08-01

    Identification of a munition fill is easier if one can determine if there is fill material present (empty versus full), and if so, the phase (solid or liquid) of the fill. Previous munition inspection efforts by the Idaho National Engineering and Environmental Laboratory (INEEL) determined that resonance information could determine the fill. A portable, noncontacting laser-acoustic system was developed by INEEL that uses a low-power laser system to measure the container`s vibration characteristics in response to an acoustic excitation. These vibration characteristics were shown to be functions of the fill material and munition geometry. The laser acoustic system was used to characterize the fill of over one hundred 155-mm munitions. Additional research and development using this system is being performed for the Mobile Munitions Assessment System.

  19. Filling of orbital fluid management systems

    NASA Technical Reports Server (NTRS)

    Merino, F.; Blatt, M. H.; Thies, N. C.

    1978-01-01

    A study was performed with three objectives: (1) analyze fluid management system fill under orbital conditions; (2) determine what experimentation is needed; and (3) develop an experimental program. The fluid management system was a 1.06m (41.7 in) diameter pressure vessel with screen channel device. Analyses were conducted using liquid hydrogen and N2O4. The influence of helium and autogenous pressurization systems was considered. Analyses showed that fluid management system fill will be more difficult with a cryogen than with an earth storable. The key to a successful fill with cryogens is in devising techniques for filling without vent liquid, and removing trapped vapor from the screen device at tank fill completion. This will be accomplished with prechill, fill, and vapor condensation processes. Refill will require a vent and purge process, to dilute the residual helium, prior to introducing liquid. Neither prechill, chill, nor purge processes will be required for earth storables.

  20. Grain-filling problem in 'super' rice.

    PubMed

    Yang, Jianchang; Zhang, Jianhua

    2010-01-01

    Modern rice (Oryza sativa L.) cultivars, especially the newly bred 'super' rice, have numerous spikelets on a panicle with a large yield capacity. However, these cultivars often fail to achieve their high yield potential due to poor grain-filling of later-flowering inferior spikelets (in contrast to the earlier-flowering superior spikelets). Conventional thinking to explain the poor grain-filling is the consequence of carbon limitation. Recent studies, however, have shown that carbohydrate supply should not be the major problem because they have adequate sucrose at their initial grain-filling stage. The low activities of key enzymes in carbon metabolism may contribute to the poor grain-filling. Proper field practices, such as moderate soil drying during mid- and late grain-filling stages, could solve some problems in poor grain-filling. Further studies are needed by molecular approaches to investigate the signal transport, the hormonal action, the gene expressions, and the biochemical processes in inferior spikelets.

  1. Far-field intensity of Lorentz related beams

    NASA Astrophysics Data System (ADS)

    Peng, Xi; Chen, Chidao; Chen, Bo; Peng, Yulian; Zhou, Meiling; Zhang, Liping; Li, Dongdong; Deng, Dongmei

    2016-12-01

    We introduce a sufficient condition under which the Lorentz beam convolution with other beams constitutes valid cross-spectral densities. Two examples are given to show how the Lorentz related beam can be used for generation of a far field being a modulated version of another one. The far-field intensity patterns in the Cartesian symmetries by the convolution operation of the Lorentz beams with multi-sinc beams, and the convolution operation of the Lorentz beams with multi-sinc Gaussian beams, are shown respectively. We find that different beam order can result distinct far field changes.

  2. Design for controllable optofluidic beam splitter

    NASA Astrophysics Data System (ADS)

    Tang, Xionggui; Liang, Shan; Li, Rujian

    2016-01-01

    A novel configuration for controllable optofluidic beam splitter is proposed, which consists of the asymmetric Y-branch waveguide and the microfluidic channel filled with fluid mixture. The beam propagation method (BPM) is employed to numerically investigate the optical performance of device in our layout. The simulated results demonstrate that arbitrary splitting ratio and low optical loss for both TE and TM mode can be easily achieved, with a low dependence of wavelength and polarization. Particularly, the optofluidic beam splitter has advantages such as compact structure and large fabrication tolerance. The proposed device provides a new way to manipulate the optical power splitting, and has wide potential applications in integrated optofluidic system.

  3. The dielectric-filled parabola - A new millimeter/submillimeter wavelength receiver/transmitter front end

    NASA Technical Reports Server (NTRS)

    Siegel, Peter H.; Dengler, Robert J.

    1991-01-01

    A design is presented for a semi-integrated millimeter/submillimeter wavelength receiver/transmitter front end incorporating a planar antenna and a solid-state device in an efficient feed structure which can be matched directly to high f-number optical systems. The feed system combines the simplicity and robustness of a dielectric substrate lens with the high gain of a parabolic reflector in a single structure that is termed a dielectric-filled parabola. The same fundamental unit can be configured as either a heterodyne or direct detection mode receiver, a power transmitter or a frequency multiplier by changing out the solid-state device and/or the integrated antenna. The structure can also be used with a small integrated antenna array in a multibeam or imaging arrangement. Design and fabrication details for the feed system are given. These are followed by beam pattern and impedance measurements taken on a microwave model when dipole, bow-tie, log-periodic, and log-spiral antennas are used as the integrated feed elements.

  4. Multi-shaped beam proof of lithography

    NASA Astrophysics Data System (ADS)

    Slodowski, Matthias; Doering, Hans-Joachim; Dorl, Wolfgang; Stolberg, Ines A.

    2010-03-01

    In this paper a full package high throughput multi electron-beam approach, called Multi Shaped Beam (MSB), for applications in mask making as well as direct write will be presented including complex proof-of-lithography results. The basic concept enables a significant exposure shot count reduction for advanced patterns compared to standard Variable Shaped Beam (VSB) systems and allows full pattern flexibility by concurrently using MSB, VSB and Cell Projection (CP). Proof of lithography results will be presented, which have been performed using a fully operational electron-beam lithography system including data path and substrate scanning by x/y-stage movement.

  5. Inversion of band patterns in spherical tumblers.

    PubMed

    Chen, Pengfei; Lochman, Bryan J; Ottino, Julio M; Lueptow, Richard M

    2009-04-10

    Bidisperse granular mixtures in spherical tumblers segregate into three bands: one at each pole and one at the equator. For low fill levels, large particles are at the equator; for high fill levels, the opposite occurs. Segregation is robust, though the transition depends on fill level, particle size, and rotational speed. Discrete element method simulations reproduce surface patterns and reveal internal structures. Particle trajectories show that small particles flow farther toward the poles than large particles in the upstream portion of the flowing layer for low fill levels leading to a band of small particles at each pole. The opposite occurs for high fill levels, though more slowly.

  6. Mekong Floods Fill Tonle Sap

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The monsoon season in Southeast Asia brings recurring, often devastating floods to countries in the region, but these floods also play a necessary role in the region's water cycle. These MODIS images centered on Cambodia reveal extensive flooding of the Mekong River, which comes in from Laos in the north, to the right of center in the images, and flows south through Cambodia and southeast through Vietnam to empty into the South China Sea. The true-color image shows the brownish, sediment-laden floodwaters filling the Mekong Delta in southern Cambodia and Vietnam on September 15, 2001. The false color image above has been enhanced to bring out the contrast between the floodwaters and the lands, with sediment-carrying floodwaters in purple. Sediment can be seen flowing into the South China Sea as well. This year's floods have affected over a million people, and 100 people have been killed in Vietnam alone. The monsoon floods bring not only devastation, but renewal. The large body of water just left of center in Cambodia is the Tonle Sap. This shallow lake plays a changing role in the regional water cycle. During the dry season, the stream-fed Tonle Sap drains via the Tonle Sab River into the Mekong River. During the wet season (June-November), flooding of the Mekong reverses the course of the Tonle Sab, roughly tripling the lake's size from about 3000 km2 to about 10,000. When the dry season returns, the lake once again begins to drain into the Mekong Delta, where it provides a flow of fresh water that balances the intrusion of salty seawater into the delta's agricultural lands. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

  7. Drift compression of an intense neutralized ion beam

    SciTech Connect

    Roy, P.K.; Yu, S.S.; Henestroza, E.; Anders, A.; Bieniosek, F.M.; Coleman, J.; Eylon, S.; Greenway, W.G.; Leitner, M.; Logan, B.G.; Waldron, W.L.; Welch, D.R.; Thoma, C.; Sefkow, A.B.; Gilson, E.P.; Efthimion, P.C.; Davidson, R.C.

    2004-10-25

    Longitudinal compression of a tailored-velocity, intense neutralized ion beam has been demonstrated. The compression takes place in a 1-2 m drift section filled with plasma to provide space-charge neutralization. An induction cell produces a head-to-tail velocity ramp that longitudinally compresses the neutralized beam, enhancing the beam peak current by a factor of 50 and producing a pulse duration of about 3 ns. this measurement has been confirmed independently with two different diagnostic systems.

  8. Experimental Testing of Dynamically Optimized Photoelectron Beams

    SciTech Connect

    Rosenzweig, J. B.; Cook, A. M.; Dunning, M.; England, R. J.; Musumeci, P.; Bellaveglia, M.; Boscolo, M.; Catani, L.; Cianchi, A.; Di Pirro, G.; Ferrario, M.; Fillipetto, D.; Gatti, G.; Palumbo, L.; Vicario, C.; Serafini, L.; Jones, S.

    2006-11-27

    We discuss the design of and initial results from an experiment in space-charge dominated beam dynamics which explores a new regime of high-brightness electron beam generation at the SPARC photoinjector. The scheme under study employs the tendency of intense electron beams to rearrange to produce uniform density, giving a nearly ideal beam from the viewpoint of space charge-induced emittance. The experiments are aimed at testing the marriage of this idea with a related concept, emittance compensation. We show that this new regime of operating photoinjector may be the preferred method of obtaining highest brightness beams with lower energy spread. We discuss the design of the experiment, including developing of a novel time-dependent, aerogel-based imaging system. This system has been installed at SPARC, and first evidence for nearly uniformly filled ellipsoidal charge distributions recorded.

  9. Experimental Testing of Dynamically Optimized Photoelectron Beams

    NASA Astrophysics Data System (ADS)

    Rosenzweig, J. B.; Cook, A. M.; Dunning, M.; England, R. J.; Musumeci, P.; Bellaveglia, M.; Boscolo, M.; Catani, L.; Cianchi, A.; Di Pirro, G.; Ferrario, M.; Fillipetto, D.; Gatti, G.; Palumbo, L.; Serafini, L.; Vicario, C.; Jones, S.

    2006-11-01

    We discuss the design of and initial results from an experiment in space-charge dominated beam dynamics which explores a new regime of high-brightness electron beam generation at the SPARC photoinjector. The scheme under study employs the tendency of intense electron beams to rearrange to produce uniform density, giving a nearly ideal beam from the viewpoint of space charge-induced emittance. The experiments are aimed at testing the marriage of this idea with a related concept, emittance compensation. We show that this new regime of operating photoinjector may be the preferred method of obtaining highest brightness beams with lower energy spread. We discuss the design of the experiment, including developing of a novel time-dependent, aerogel-based imaging system. This system has been installed at SPARC, and first evidence for nearly uniformly filled ellipsoidal charge distributions recorded.

  10. Tunable beam steering enabled by graphene metamaterials.

    PubMed

    Orazbayev, B; Beruete, M; Khromova, I

    2016-04-18

    We demonstrate tunable mid-infrared (MIR) beam steering devices based on multilayer graphene-dielectric metamaterials. The effective refractive index of such metamaterials can be manipulated by changing the chemical potential of each graphene layer. This can arbitrarily tailor the spatial distribution of the phase of the transmitted beam, providing mechanisms for active beam steering. Three different beam steerer (BS) designs are discussed: a graded-index (GRIN) graphene-based metamaterial block, an array of metallic waveguides filled with graphene-dielectric metamaterial and an array of planar waveguides created in a graphene-dielectric metamaterial block with a specific spatial profile of graphene sheets doping. The performances of the BSs are numerically analyzed, showing the tunability of the proposed designs for a wide range of output angles (up to approximately 70°). The proposed graphene-based tunable beam steering can be used in tunable transmitter/receiver modules for infrared imaging and sensing.

  11. Beam discharge excited by distributed virtual cathode

    SciTech Connect

    Barabanov, V. N.; Dubinov, A. E.; Loiko, M. V.; Saikov, S. K.; Selemir, V. D.; Tarakanov, V. P.

    2012-02-15

    A new type of beam discharge, i.e., beam discharge with a distributed virtual cathode (VC) is proposed and considered by numerical simulation. The discharge is established during counter motion of high-current electron beams in a gas-filled equipotential cavity and is characterized by a state of hot dense electron plasma of primary electrons. The discharge temporal dynamics is studied. It is shown that the VC lifetime depends linearly from this sum in a wide range of the sum of beam currents, from the boundary current of two-beam instability to the critical current of Pierce instability. Generation of nonlinear electrostatic structures shaped as phase bubbles in the discharge is detected, and their dynamics is studied. The parameters are determined, at which the multiple coexistence of phase bubbles and their coalescence during collisions is observed.

  12. Gap Filling of Precipitation Data by SSA - Singular Spectrum Analysis

    NASA Astrophysics Data System (ADS)

    Filho, A. S. F.; Lima, G. A. R.

    2016-10-01

    From the macroscopic standpoint, the precipitation time series is obtained from observation of natural systems rather than in the laboratory. These time series are often full of gaps (missing values) due to the conditions under which the measurements are made. Missing values give rise to various problems in spectral estimation, inhibit statistical analysis and in specifying boundary conditions for numerical models. Hence, gap filling is necessary in environmental science. The aim of this study is to highlight the application of the SSA forecasting algorithm to fill in missing values to real-life time series. It was applied to several monthly precipitation time series recorded over a large savannah area in Brazil. The results are promising and the accuracy and reliability depend on the pattern and relative length of the gaps with respect to the total length of the time series and presence of noise.

  13. Coherent beam-beam interaction with four colliding beams

    NASA Astrophysics Data System (ADS)

    Podobedov, B.; Siemann, R. H.

    1995-09-01

    The coherent beam-beam interaction in the absence of Landau damping is studied with a computer simulation of four space-charge-compensated colliding beams. Results are presented for the modes, phase space structures, widths, and growth rates of coherent beam-beam resonances. These results are compared with solutions of the Vlasov equation, and with measurements made at the Dispositif de Collisions dans l'Igloo (DCI) storage ring in Orsay, France, which operated with space-charge-compensated colliding beams.

  14. Development of a novel linearly-filled Derenzo microPET phantom

    PubMed Central

    Cox, Benjamin L; Graves, Stephen A; Farhoud, Mohammed; Barnhart, Todd E; Jeffery, Justin J; Eliceiri, Kevin W; Nickles, Robert J

    2016-01-01

    Positron emission tomography (PET) phantoms are used to calibrate PET scanners so that inter-scanner and inter-isotope comparison can be made between PET datasets. Hot rod style phantoms have a hole pattern, which is filled with a positron-emitting isotope and typically involves using two radioisotope reservoirs with the pattern created with channels in between. However, this configuration is difficult to fill and requires an excess of activity and volume. Here we present an alternative design, a phantom that is linearly filled-one channel at a time. The process of fabrication of prototypes of the design is described and PET images of the prototyped phantom are also shown for a variety of commonly used radioisotopes (52Mn, 64Cu, 76Br, 124I). This design allows for a large reduction in isotope volume and required filling time making a quality assurance (QA) protocol safer, more efficient and less costly. PMID:27508106

  15. BEAM-BEAM SIMULATIONS FOR DOUBLE-GAUSSIAN BEAMS.

    SciTech Connect

    MONTAG, C.; MALITSKY, N.; BEN-ZVI, I.; LITVINENKO, V.

    2005-05-16

    Electron cooling together with intra-beam scattering results in a transverse distribution that can best be described by a sum of two gaussians, one for the high-density core and one for the tails of the distribution. Simulation studies are being performed to understand the beam-beam interaction of these double-gaussian beams. Here we report the effect of low-frequency random tune modulations on diffusion in double-gaussian beams and compare the effects to those in beam-beam interactions with regular gaussian beams and identical tune shift parameters.

  16. Scattering apodizer for laser beams

    DOEpatents

    Summers, M.A.; Hagen, W.F.; Boyd, R.D.

    1984-01-01

    A method is disclosed for apodizing a laser beam to smooth out the production of diffraction peaks due to optical discontinuities in the path of the laser beam, such method comprising introduction of a pattern of scattering elements for reducing the peak intensity in the region of such optical discontinuities, such pattern having smoothly tapering boundaries in which the distribution density of the scattering elements is tapered gradually to produce small gradients in the distribution density, such pattern of scattering elements being effective to reduce and smooth out the diffraction effects which would otherwise be produced. The apodizer pattern may be produced by selectively blasting a surface of a transparent member with fine abrasive particles to produce a multitude of minute pits. In one embodiment, a scattering apodizer pattern is employed to overcome diffraction patterns in a multiple element crystal array for harmonic conversion of a laser beam. The interstices and the supporting grid between the crystal elements are obscured by the gradually tapered apodizer pattern of scattering elements.

  17. Scattering apodizer for laser beams

    DOEpatents

    Summers, Mark A.; Hagen, Wilhelm F.; Boyd, Robert D.

    1985-01-01

    A method is disclosed for apodizing a laser beam to smooth out the production of diffraction peaks due to optical discontinuities in the path of the laser beam, such method comprising introduction of a pattern of scattering elements for reducing the peak intensity in the region of such optical discontinuities, such pattern having smoothly tapering boundaries in which the distribution density of the scattering elements is tapered gradually to produce small gradients in the distribution density, such pattern of scattering elements being effective to reduce and smooth out the diffraction effects which would otherwise be produced. The apodizer pattern may be produced by selectively blasting a surface of a transparent member with fine abrasive particles to produce a multitude of minute pits. In one embodiment, a scattering apodizer pattern is employed to overcome diffraction patterns in a multiple element crystal array for harmonic conversion of a laser beam. The interstices and the supporting grid between the crystal elements are obscured by the gradually tapered apodizer pattern of scattering elements.

  18. 30 CFR 817.72 - Disposal of excess spoil: Valley fill/head-of-hollow fills.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    .... Uncontrolled surface drainage may not be directed over the outslope of the fill. (2) Runoff from areas above the fill and runoff from the surface of the fill shall be diverted into stabilized diversion channels designed to meet the requirements of § 817.43 and to safely pass the runoff from a 100-year,...

  19. 30 CFR 816.72 - Disposal of excess spoil: Valley fills/head-of-hollow fills.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    .... Uncontrolled surface drainage may not be directed over the outslope of the fill. (2) Runoff from areas above the fill and runoff from the surface of the fill shall be diverted into stabilized diversion channels designed to meet the requirements of § 816.43 and, in addition, to safely pass the runoff from a...

  20. 30 CFR 816.72 - Disposal of excess spoil: Valley fills/head-of-hollow fills.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... such that the final slope after settlement will be toward properly designed drainage channels.... The maximum slope of the top of the fill shall be 33h:1v (3 percent). A drainage pocket may be.... Terraces on the fill shall be graded with a 3 to 5 percent grade toward the fill and a 1 percent...

  1. 30 CFR 817.72 - Disposal of excess spoil: Valley fill/head-of-hollow fills.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... such that the final slope after settlement will be toward properly designed drainage channels... slope of the top of the fill shall be 33h:lv (3 percent). A drainage pocket may be maintained at the... fill shall be graded with a 3 to 5 percent grade toward the fill and a 1 percent slope toward the...

  2. 30 CFR 817.72 - Disposal of excess spoil: Valley fill/head-of-hollow fills.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... into the design and construction of the fill as follows: (1) The fill shall have, along the vertical... and from seeps and springs in the foundation of the disposal area. Rocks used in the rock core and... head of the fill during and after construction, to intercept surface runoff and discharge the...

  3. Generation of low-divergence laser beams

    DOEpatents

    Kronberg, James W.

    1993-01-01

    Apparatus for transforming a conventional beam of coherent light, having a Gaussian energy distribution and relatively high divergence, into a beam in which the energy distribution approximates a single, non-zero-order Bessel function and which therefore has much lower divergence. The apparatus comprises a zone plate having transmitting and reflecting zones defined by the pattern of light interference produced by the combination of a beam of coherent light with a Gaussian energy distribution and one having such a Bessel distribution. The interference pattern between the two beams is a concentric array of multiple annuli, and is preferably recorded as a hologram. The hologram is then used to form the transmitting and reflecting zones by photo-etching portions of a reflecting layer deposited on a plate made of a transmitting material. A Bessel beam, containing approximately 50% of the energy of the incident beam, is produced by passing a Gaussian beam through such a Bessel zone plate. The reflected beam, also containing approximately 50% of the incident beam energy and having a Bessel energy distribution, can be redirected in the same direction and parallel to the transmitted beam. Alternatively, a filter similar to the Bessel zone plate can be placed within the resonator cavity of a conventional laser system having a front mirror and a rear mirror, preferably axially aligned with the mirrors and just inside the front mirror to generate Bessel energy distribution light beams at the laser source.

  4. Generation of low-divergence laser beams

    DOEpatents

    Kronberg, J.W.

    1993-09-14

    Apparatus for transforming a conventional beam of coherent light, having a Gaussian energy distribution and relatively high divergence, into a beam in which the energy distribution approximates a single, non-zero-order Bessel function and which therefore has much lower divergence. The apparatus comprises a zone plate having transmitting and reflecting zones defined by the pattern of light interference produced by the combination of a beam of coherent light with a Gaussian energy distribution and one having such a Bessel distribution. The interference pattern between the two beams is a concentric array of multiple annuli, and is preferably recorded as a hologram. The hologram is then used to form the transmitting and reflecting zones by photo-etching portions of a reflecting layer deposited on a plate made of a transmitting material. A Bessel beam, containing approximately 50% of the energy of the incident beam, is produced by passing a Gaussian beam through such a Bessel zone plate. The reflected beam, also containing approximately 50% of the incident beam energy and having a Bessel energy distribution, can be redirected in the same direction and parallel to the transmitted beam. Alternatively, a filter similar to the Bessel zone plate can be placed within the resonator cavity of a conventional laser system having a front mirror and a rear mirror, preferably axially aligned with the mirrors and just inside the front mirror to generate Bessel energy distribution light beams at the laser source. 11 figures.

  5. Determinants of Toxicity, Patterns of Failure, and Outcome Among Adult Patients With Soft Tissue Sarcomas of the Extremity and Superficial Trunk Treated With Greater Than Conventional Doses of Perioperative High-Dose-Rate Brachytherapy and External Beam Radiotherapy

    SciTech Connect

    San Miguel, Inigo; San Julian, Mikel; Cambeiro, Mauricio; Sanmamed, Miguel Fernandez; Vazquez-Garcia, Blanca; Pagola, Maria; Gaztanaga, Miren; Martin-Algarra, Salvador; Martinez-Monge, Rafael

    2011-11-15

    Purpose: The present study was undertaken to determine factors predictive of toxicity, patterns of failure, and survival in 60 adult patients with soft tissue sarcomas of the extremity and superficial trunk treated with combined perioperative high-dose-rate brachytherapy and external beam radiotherapy. Methods and Materials: The patients were treated with surgical resection and perioperative high-dose-rate brachytherapy (16 or 24 Gy) for negative and close/microscopically positive resection margins, respectively. External beam radiotherapy (45 Gy) was added postoperatively to reach a 2-Gy equivalent dose of 62.9 and 72.3 Gy, respectively. Adjuvant chemotherapy with ifosfamide and doxorubicin was given to patients with advanced high-grade tumors. Results: Grade 3 toxic events were observed in 18 patients (30%) and Grade 4 events in 6 patients (10%). No Grade 5 events were observed. A location in the lower limb was significant for Grade 3 or greater toxic events on multivariate analysis (p = .013), and the tissue volume encompassed by the 150% isodose line showed a trend toward statistical significance (p = .086). The local control, locoregional control, and distant control rate at 9 years was 77.4%, 69.5%, and 63.8%, respectively. On multivariate analysis, microscopically involved margins correlated with local control (p = .036) and locoregional control (p = .007) and tumor size correlated with distant metastases (p = .004). The 9-year disease-free survival and overall survival rate was 47.0% and 61.5%, respectively. Multivariate analysis showed poorer disease-free survival rates for patients with tumors >6 cm (p = .005) and microscopically involved margins (p = .043), and overall survival rates decreased with increasing tumor size (p = .011). Conclusions: Grade 3 or greater wound complications can probably be decreased using meticulous treatment planning to decrease the tissue volume encompassed by the 150% isodose line, especially in lower limb locations

  6. Maskless micro-ion-beam reduction lithography system

    DOEpatents

    Leung, Ka-Ngo; Barletta, William A.; Patterson, David O.; Gough, Richard A.

    2005-05-03

    A maskless micro-ion-beam reduction lithography system is a system for projecting patterns onto a resist layer on a wafer with feature size down to below 100 nm. The MMRL system operates without a stencil mask. The patterns are generated by switching beamlets on and off from a two electrode blanking system or pattern generator. The pattern generator controllably extracts the beamlet pattern from an ion source and is followed by a beam reduction and acceleration column.

  7. Droplet Measurement below Single-Layer Grid Fill

    NASA Astrophysics Data System (ADS)

    Vitkovic, Pavol

    2016-03-01

    The main part of the heat transfer in a cooling tower is in a fill zone. This one is consist of a cooling fill. For the cooling tower is used a film fill or grid fill or splash fill in the generally. The grid fill has lower heat transfer performance like film fill usually. But their advantage is high resistance to blockage of the fill. The grid fill is consisted with independent layers made from plastic usually. The layers consist of several bars connected to the different shapes. For experiment was used the rhombus shape. The drops diameter was measured above and below the Grid fill.

  8. Left ventricular diastolic filling with an implantable ventricular assist device: beat to beat variability with overall improvement

    NASA Technical Reports Server (NTRS)

    Nakatani, S.; Thomas, J. D.; Vandervoort, P. M.; Zhou, J.; Greenberg, N. L.; Savage, R. M.; McCarthy, P. M.

    1997-01-01

    OBJECTIVES: We studied the effects of left ventricular (LV) unloading by an implantable ventricular assist device on LV diastolic filling. BACKGROUND: Although many investigators have reported reliable systemic and peripheral circulatory support with implantable LV assist devices, little is known about their effect on cardiac performance. METHODS: Peak velocities of early diastolic filling, late diastolic filling, late to early filling ratio, deceleration time of early filling, diastolic filling period and atrial filling fraction were measured by intraoperative transesophageal Doppler echocardiography before and after insertion of an LV assist device in eight patients. A numerical model was developed to simulate this situation. RESULTS: Before device insertion, all patients showed either a restrictive or a monophasic transmitral flow pattern. After device insertion, transmitral flow showed rapid beat to beat variation in each patient, from abnormal relaxation to restrictive patterns. However, when the average values obtained from 10 consecutive beats were considered, overall filling was significantly normalized from baseline, with early filling velocity falling from 87 +/- 31 to 64 +/- 26 cm/s (p < 0.01) and late filling velocity rising from 8 +/- 11 to 32 +/- 23 cm/s (p < 0.05), resulting in an increase in the late to early filling ratio from 0.13 +/- 0.18 to 0.59 +/- 0.38 (p < 0.01) and a rise in the atrial filling fraction from 8 +/- 10% to 26 +/- 17% (p < 0.01). The deceleration time (from 112 +/- 40 to 160 +/- 44 ms, p < 0.05) and the filling period corrected by the RR interval (from 39 +/- 8% to 54 +/- 10%, p < 0.005) were also significantly prolonged. In the computer model, asynchronous LV assistance produced significant beat to beat variation in filling indexes, but overall a normalization of deceleration time as well as other variables. CONCLUSIONS: With LV assistance, transmitral flow showed rapidly varying patterns beat by beat in each patient, but

  9. Silicon microfabricated beam expander

    SciTech Connect

    Othman, A. Ibrahim, M. N.; Hamzah, I. H.; Sulaiman, A. A.; Ain, M. F.

    2015-03-30

    The feasibility design and development methods of silicon microfabricated beam expander are described. Silicon bulk micromachining fabrication technology is used in producing features of the structure. A high-precision complex 3-D shape of the expander can be formed by exploiting the predictable anisotropic wet etching characteristics of single-crystal silicon in aqueous Potassium-Hydroxide (KOH) solution. The beam-expander consist of two elements, a micromachined silicon reflector chamber and micro-Fresnel zone plate. The micro-Fresnel element is patterned using lithographic methods. The reflector chamber element has a depth of 40 µm, a diameter of 15 mm and gold-coated surfaces. The impact on the depth, diameter of the chamber and absorption for improved performance are discussed.

  10. Laser beam steering device

    NASA Technical Reports Server (NTRS)

    Motamedi, M. E.; Andrews, A. P.; Gunning, W. J.

    1993-01-01

    Agile beam steering is a critical requirement for airborne and space based LIDAR and optical communication systems. Design and test results are presented for a compact beam steering device with low inertia which functions by dithering two complementary (positive and negative) binary optic microlens arrays relative to each other in directions orthogonal to the direction of light propagation. The miniaturized system has been demonstrated at scan frequencies as high as 300 Hz, generating a 13 x 13 spot array with a total field of view of 2.4 degrees. The design is readily extendable to a 9.5 degree field of view and a 52 x 52 scan pattern. The system is compact - less than 2 in. on a side. Further size reductions are anticipated.

  11. Nematic wetting and filling of crenellated surfaces

    NASA Astrophysics Data System (ADS)

    Silvestre, N. M.; Eskandari, Z.; Patrício, P.; Romero-Enrique, J. M.; Telo da Gama, M. M.

    2012-07-01

    We investigate nematic wetting and filling transitions of crenellated surfaces (rectangular gratings) by numerical minimization of the Landau-de Gennes free energy as a function of the anchoring strength, for a wide range of the surface geometrical parameters: depth, width, and separation of the crenels. We have found a rich phase behavior that depends in detail on the combination of the surface parameters. By comparison to simple fluids, which undergo a continuous filling or unbending transition, where the surface changes from a dry to a filled state, followed by a wetting or unbinding transition, where the thickness of the adsorbed fluid becomes macroscopic and the interface unbinds from the surface, nematics at crenellated surfaces reveal an intriguingly rich behavior: in shallow crenels only wetting is observed, while in deep crenels, only filling transitions occur; for intermediate surface geometrical parameters, a new class of filled states is found, characterized by bent isotropic-nematic interfaces, which persist for surfaces structured on large scales, compared to the nematic correlation length. The global phase diagram displays two wet and four filled states, all separated by first-order transitions. For crenels in the intermediate regime re-entrant filling transitions driven by the anchoring strength are observed.

  12. Converging shock generation with cone target filled with low density foam

    NASA Astrophysics Data System (ADS)

    Shigemori, K.; Yamamoto, T.; Hironaka, Y.; Kawashima, T.; Hattori, S.; Nagatomo, H.; Kato, H.; Sato, N.; Watari, T.; Takagi, M.

    2016-05-01

    We have been developing an alternative scheme of fast ignition of inertial confinement targets with converging shock. Experiments were carried out on GEKKO-XII laser facility at ILE, Osaka University. We employed Au cone targets filled with low- density RF foam (2 mg/cm3). The foam-filled cone targets were irradiated by three beams of the GEKKO-XII, with pulse duration of 1.3 ns, intensity of ∼ 1014 W/cm2 in 2 :λ(ω0.527μm). Self-emission at the tip of cone was observed by one-dimensional streaked optical pyrometer (SOP) and two-dimensional images.

  13. Apparatus and method for laser beam diagnosis

    DOEpatents

    Salmon, Jr., Joseph T.

    1991-01-01

    An apparatus and method is disclosed for accurate, real time monitoring of the wavefront curvature of a coherent laser beam. Knowing the curvature, it can be quickly determined whether the laser beam is collimated, or focusing (converging), or de-focusing (diverging). The apparatus includes a lateral interferometer for forming an interference pattern of the laser beam to be diagnosed. The interference pattern is imaged to a spatial light modulator (SLM), whose output is a coherent laser beam having an image of the interference pattern impressed on it. The SLM output is focused to obtain the far-field diffraction pattern. A video camera, such as CCD, monitors the far-field diffraction pattern, and provides an electrical output indicative of the shape of the far-field pattern. Specifically, the far-field pattern comprises a central lobe and side lobes, whose relative positions are indicative of the radius of curvature of the beam. The video camera's electrical output may be provided to a computer which analyzes the data to determine the wavefront curvature of the laser beam.

  14. Apparatus and method for laser beam diagnosis

    DOEpatents

    Salmon, J.T. Jr.

    1991-08-27

    An apparatus and method are disclosed for accurate, real time monitoring of the wavefront curvature of a coherent laser beam. Knowing the curvature, it can be quickly determined whether the laser beam is collimated, or focusing (converging), or de-focusing (diverging). The apparatus includes a lateral interferometer for forming an interference pattern of the laser beam to be diagnosed. The interference pattern is imaged to a spatial light modulator (SLM), whose output is a coherent laser beam having an image of the interference pattern impressed on it. The SLM output is focused to obtain the far-field diffraction pattern. A video camera, such as CCD, monitors the far-field diffraction pattern, and provides an electrical output indicative of the shape of the far-field pattern. Specifically, the far-field pattern comprises a central lobe and side lobes, whose relative positions are indicative of the radius of curvature of the beam. The video camera's electrical output may be provided to a computer which analyzes the data to determine the wavefront curvature of the laser beam. 11 figures.

  15. [Amalgam fillings and T-lymphocyte changes].

    PubMed

    Giuliani, M; Rumi, C; Marciani, F; Boari, A; Rumi, G; Di Felice, R

    1990-07-01

    Dental amalgam and nickel alloys have been considered quite safe. Previous authors reported the effect of dental amalgam and nickel alloys on human T-lymphocytes modifications after amalgam dental fillings, into dose-dependence of any modifications and into possible temporary. Eight patients were subjected to dental care with amalgam dental fillings. Drawings of blood were executed at start, fifteen days after late fillings and two months later. The results about modifications of T-lymphocytes were not univocal. We believe, at now, that temporary modifications of the immunity seem to be related to a cytotoxic mechanism.

  16. Numerical simulation of filling a magnetic flux tube with a cold plasma: Anomalous plasma effects

    NASA Technical Reports Server (NTRS)

    Singh, Nagendra; Leung, W. C.

    1995-01-01

    Large-scale models of plasmaspheric refilling have revealed that during the early stage of the refilling counterstreaming ion beams are a common feature. However, the instability of such ion beams and its effect on refilling remain unexplored. In order to learn the basic effects of ion beam instabilities on refilling, we have performed numerical simulations of the refilling of an artificial magnetic flux tube. (The shape and size of the tube are assumed so that the essential features of the refilling problem are kept in the simulation and at the same time the small scale processes driven by the ion beams are sufficiently resolved.) We have also studied the effect of commonly found equatorially trapped warm and/or hot plasma on the filling of a flux tube with a cold plasma. Three types of simulation runs have been performed.

  17. Communication patterns and allocation strategies.

    SciTech Connect

    Leung, Vitus Joseph; Mache, Jens Wolfgang; Bunde, David P.

    2004-01-01

    Motivated by observations about job runtimes on the CPlant system, we use a trace-driven microsimulator to begin characterizing the performance of different classes of allocation algorithms on jobs with different communication patterns in space-shared parallel systems with mesh topology. We show that relative performance varies considerably with communication pattern. The Paging strategy using the Hilbert space-filling curve and the Best Fit heuristic performed best across several communication patterns.

  18. Coherent beam-beam effects, theory & observations

    SciTech Connect

    Yuri I Alexahin

    2003-07-16

    Current theoretical understanding of the coherent beam-beam effect as well as its experimental observations are discussed: conditions under which the coherent beambeam modes may appear, possibility of their resonant interaction (coherent resonances), stability of beam-beam oscillations in the presence of external impedances. A special attention is given to the coherent beam-beam modes of finite length bunches: the synchro-betatron coupling is shown to provide reduction in the coherent tuneshift and--at the synchrotron tune values smaller than the beam-beam parameter--Landau damping by overlapping synchrotron satellites.

  19. Variable xy-UV beam expander for high-power laser beam shaping

    NASA Astrophysics Data System (ADS)

    Nadorff, Georg; DeWitt, Frank; Lindau, Sten

    2012-10-01

    A five element zoomable anamorphic beam expander is designed and fabricated for a laser illumination system used in the manufacture of patterned micro-circuit substrates. The beam expander is the front end of a Gaussian to top-hat beam shaping illuminator. The tightly toleranced optical system downstream of the beam expander should not be readjusted with changes to the input beam. The job of the beam expander is to maintain, independent of the input beam, a constant diffraction limited output beam size as well as a specific waist location. A high power quasi-CW laser at 355 nm is employed for high throughput. The specifications of the laser allow for a range of x,y-beam diameters (ellipticity), x,y-waist locations (astigmatism), and x,y-divergence. As the laser's frequency tripling crystal is exposed to high fluence over time, the beam parameters will change. At some point the laser is exchanged for a new one, and a new set of beam parameters is presented to the beam expander. Movable cylindrical lenses enable the independent adjustment of x- and y-beam parameters. The mounting cells are motorized to enable adjustments remotely. We present the optical design approach using Gaussian beam ray tracing and discuss the mechanical implementation.

  20. Transparent Metal-Salt-Filled Polymeric Radiation Shields

    NASA Technical Reports Server (NTRS)

    Edwards, David; Lennhoff, John; Harris, George

    2003-01-01

    "COR-RA" (colorless atomic oxygen resistant -- radiation shield) is the name of a transparent polymeric material filled with x-ray-absorbing salts of lead, bismuth, cesium, and thorium. COR-RA is suitable for use in shielding personnel against bremsstrahlung radiation from electron-beam welding and industrial and medical x-ray equipment. In comparison with lead-foil and leaded-glass shields that give equivalent protection against x-rays (see table), COR-RA shields are mechanically more durable. COR-RA absorbs not only x-rays but also neutrons and rays without adverse effects on optical or mechanical performance. The formulation of COR-RA with the most favorable mechanical-durability and optical properties contains 22 weight percent of bismuth to absorb x-rays, plus 45 atomic percent hydrogen for shielding against neutrons.

  1. Asymmetric Laguerre-Gaussian beams

    NASA Astrophysics Data System (ADS)

    Kovalev, A. A.; Kotlyar, V. V.; Porfirev, A. P.

    2016-06-01

    We introduce a family of asymmetric Laguerre-Gaussian (aLG) laser beams. The beams have been derived via a complex-valued shift of conventional LG beams in the Cartesian plane. While propagating in a uniform medium, the first bright ring of the aLG beam becomes less asymmetric and the energy is redistributed toward peripheral diffraction rings. The projection of the orbital angular momentum (OAM) onto the optical axis is calculated. The OAM is shown to grow quadratically with increasing asymmetry parameter of the aLG beam, which equals the ratio of the shift to the waist radius. Conditions for the OAM becoming equal to the topological charge have been derived. For aLG beams with zero radial index, we have deduced an expression to define the intensity maximum coordinates and shown the crescent-shaped intensity pattern to rotate during propagation. Results of the experimental generation and rotation of aLG beams agree well with theoretical predictions.

  2. Ion Beam Modification of Materials

    SciTech Connect

    Averback, B; de la Rubia, T D; Felter, T E; Hamza, A V; Rehn, L E

    2005-10-10

    This volume contains the proceedings of the 14th International Conference on Ion Beam Modification of Materials, IBMM 2004, and is published by Elsevier-Science Publishers as a special issue of Nuclear Instruments and Methods B. The conference series is the major international forum to present and discuss recent research results and future directions in the field of ion beam modification, synthesis and characterization of materials. The first conference in the series was held in Budapest, Hungary, 1978, and subsequent conferences were held every two years at locations around the Globe, most recently in Japan, Brazil, and the Netherlands. The series brings together physicists, materials scientists, and ion beam specialists from all over the world. The official conference language is English. IBMM 2004 was held on September 5-10, 2004. The focus was on materials science involving both basic ion-solid interaction processes and property changes occurring either during or subsequent to ion bombardment and ion beam processing in relation to materials and device applications. Areas of research included Nanostructures, Multiscale Modeling, Patterning of Surfaces, Focused Ion Beams, Defects in Semiconductors, Insulators and Metals, Cluster Beams, Radiation Effects in Materials, Photonic Devices, Ion Implantation, Ion Beams in Biology and Medicine including New Materials, Imaging, and Treatment.

  3. Microleakage of root-end filling materials.

    PubMed

    Fogel, H M; Peikoff, M D

    2001-07-01

    The purpose of this study was to evaluate the microleakage of various root-end filling materials using a fluid filtration system. Sixty extracted human single-rooted teeth were used. The crowns were removed, the canals prepared, and root-end fillings placed. The samples were divided into two control and five experimental groups. The root-end filling materials tested were: amalgam, Intermediate Restorative Material (IRM), a dentin-bonded resin, Super-EBA, and mineral trioxide aggregate. The results showed that amalgam root-end fillings demonstrated significantly more microleakage than Super-EBA, dentin-bonded resin, or mineral trioxide aggregate. There was no significant difference between amalgam and IRM. However IRM was also not significantly different from the other three groups. There were no significant differences between the other three groups.

  4. 5 CFR 362.303 - Filling positions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... possesses a Ph.D. or equivalent degree directly related to the STEM position the agency is seeking to fill... candidate possesses a Ph.D. or equivalent degree directly related to the position the agency is seeking...

  5. 5 CFR 362.303 - Filling positions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... possesses a Ph.D. or equivalent degree directly related to the STEM position the agency is seeking to fill... candidate possesses a Ph.D. or equivalent degree directly related to the position the agency is seeking...

  6. PERVAPORATION USING ADSORBENT-FILLED MEMBRANES

    EPA Science Inventory

    Membranes containing selective fillers, such as zeolites and activated carbon, can improve the separation by pervaporation. Applications of adsorbent-filled membranes in pervaporation have been demonstrated by a number of studies. These applications include removal of organic co...

  7. Film fill for power plant cooling towers

    SciTech Connect

    Mirsky, G.R. ); Monjoie, M. )

    1991-01-01

    This paper reports on film fill, which is the use of flat or formed sheets to provide a surface upon which liquid and air come in contact with each other to affect the exchange of heat. The only other fill options available to a cooling tower designer is the use of splash fill or combinations whereby heat exchange occurs on the surface of water droplets, or both. As film fill allows the designer the opportunity to build a more compact, cost effective, energy efficient cooling tower; this type of fill material is receiving ever increasing acceptance and finding it way into more and more cooling tower applications. film fill is used to both counterflow and crossflow cooling towers, from small air conditioning applications to large natural draft towers serving 1300 to 1500 M.W. power plants around the world. It is being used in applications using unfiltered water high in suspended solids, high concentrations of dissolved salts, water carrying fibers, silt, mud, treated and untreated waste effluent, scale etc. These situations are caused by users who are: trying to reduce water make-up, using untreated or unfiltered water, or trying to save on the cost of chemical treatment.

  8. Capillarity in metal casting mold filling

    NASA Astrophysics Data System (ADS)

    Hilden, Jon L.

    In metal casting processes, surface tension of the molten metal typically resists filling of the metal into the mold. The effects are greater for smaller mold cavities, and ultimately, the smallest cavities may not be filled. Surface tension forces can be overcome by applying pressure (head) to the molten metal, thus forcing metal into the cavities. However, a pressure-window will exist, too little pressure resulting in non-filled cavities and too much pressure resulting in penetration of the mold, which is itself porous. Filling-pressure windows are investigated for cylindrical-shaped mold cavities on both a theoretical and experimental basis. The lower bound of the filling pressure window is examined by treating cylindrical mold cavities as cylinders lined with packed spheres representing mold particles. The upper bound is examined by treating the mold as a 3-D array of close-packed spheres. The experimental work concerns industrial-scale vacuum investment casting of superalloy IN718 into molds containing various cylindrical mold cavities at various heights (heads). The experimental results are found to be in good agreement with the numerical modeling predictions for filling of rough (sphere-lined) cylindrical mold cavities.

  9. Monolithic integration of optical grade GaAs on Si (001) substrates deeply patterned at a micron scale

    SciTech Connect

    Bietti, Sergio; Scaccabarozzi, Andrea; Bonera, Emiliano; Miglio, Leo; Sanguinetti, Stefano; Frigeri, Cesare; Falub, Claudiu V.; Känel, Hans von

    2013-12-23

    Dense arrays of micrometric crystals, with areal filling up to 93%, are obtained by depositing GaAs in a mask-less molecular beam epitaxy process onto Si substrates. The substrates are patterned into tall, micron sized pillars. Faceted high aspect ratio GaAs crystals are achieved by tuning the Ga adatom for short surface diffusion lengths. The crystals exhibit bulk-like optical quality due to defect termination at the sidewalls. Simultaneously, the thermal strain induced by different thermal expansion parameters of GaAs and Si is fully relieved. This opens the route to thick film applications without crack formation and wafer bowing.

  10. Plasma-filled applied B ion diode experiments using a plasma opening switch

    SciTech Connect

    Renk, T.J. )

    1994-12-15

    In order for a plasma opening switch (POS) to open quickly and transfer power efficiently from an inductively charged vacuum transmission line to an applied B ion diode, the load impedance of the ion diode may be required to have an initial low impedance phase. A plasma-filled diode has such an impedance history. To test the effect of a plasma-filled diode on POS-diode coupling, a drifting plasma was introduced from the cathode side of an applied B ion diode operated on the LION accelerator (1.5 MV, 4 [Omega], 40 ns) at Cornell University. This plasma readily crossed the 2.1 T magnetic insulation field of the diode, and resulted in both increased diode electrical power, and an increased ability of the ion beam to remove material from a target. The plasma did not appear to have a noticeable effect on local beam steering angle.

  11. Disorder-induced heating of ultracold neutral plasmas created from atoms in partially filled optical lattices

    NASA Astrophysics Data System (ADS)

    Murphy, D.; Sparkes, B. M.

    2016-08-01

    We quantify the disorder-induced heating (DIH) of ultracold neutral plasmas (UCNPs) created from cold atoms in optical lattices with partial filling fractions, using a conservation of energy model involving the spatial correlations of the initial state and the equation of state in thermal equilibrium for a one-component plasma. We show, for experimentally achievable filling fractions, that the ionic Coulomb coupling parameter could be increased to a degree comparable to other proposed DIH-mitigation schemes. Molecular dynamics simulations were performed with compensation for finite-size and periodic boundary effects, which agree with calculations using the model. Reduction of DIH using optical lattices will allow for the study of strongly coupled plasma physics using low-density, low-temperature, laboratory-based plasmas, and lead to improved brightness in UCNP-based cold electron and ion beams, where DIH is otherwise a fundamental limitation to beam focal sizes and diffraction imaging capability.

  12. Experimental Study of High-Z Gas Buffers in Gas-Filled ICF Engines

    SciTech Connect

    Rhodes, M A; Kane, J; Loosmore, G; DeMuth, J; Latkowski, J

    2010-12-03

    ICF power plants, such as the LIFE scheme at LLNL, may employ a high-Z, target-chamber gas-fill to moderate the first-wall heat-pulse due to x-rays and energetic ions released during target detonation. To reduce the uncertainties of cooling and beam/target propagation through such gas-filled chambers, we present a pulsed plasma source producing 2-5 eV plasma comprised of high-Z gases. We use a 5-kJ, 100-ns theta discharge for high peak plasma-heating-power, an electrode-less discharge for minimizing impurities, and unobstructed axial access for diagnostics and beam (and/or target) propagation studies. We will report on the plasma source requirements, design process, and the system design.

  13. Plasma-filled applied B ion diode experiments using a plasma opening switch

    NASA Astrophysics Data System (ADS)

    Renk, T. J.

    1994-12-01

    In order for a plasma opening switch (POS) to open quickly and transfer power efficiently from an inductively charged vacuum transmission line to an applied B ion diode, the load impedance of the ion diode may be required to have an initial low impedance phase. A plasma-filled diode has such an impedance history. To test the effect of a plasma-filled diode on POS-diode coupling, a drifting plasma was introduced from the cathode side of an applied B ion diode operated on the LION accelerator (1.5 MV, 4 Ohm, 40 ns) at Cornell University. This plasma readily crossed the 2.1 T magnetic insulation field of the diode, and resulted in both increased diode electrical power, and an increased ability of the ion beam to remove material from a target. The plasma did not appear to have a noticeable effect on local beam steering angle.

  14. TRANSIENT BEAM LOADING EFFECTS IN RF SYSTEMS IN JLEIC

    SciTech Connect

    Wang, Haipeng; Guo, Jiquan; Rimmer, Robert A.; Wang, Shaoheng

    2016-05-01

    The pulsed electron bunch trains generated from the Continuous Electron Beam Accelerator Facility (CEBAF) linac to inject into the proposed Jefferson Lab Electron Ion Collider (JLEIC) e-ring will produce transient beam loading effects in the Superconducting Radio Frequency (SRF) systems that, if not mitigated, could cause unacceptably large beam energy deviation in the injection capture, or exceed the energy acceptance of CEBAF’s recirculating arcs. In the electron storage ring, the beam abort or ion clearing gaps or uneven bucket filling can cause large beam phase transients in the (S)RF cavity control systems and even beam loss due to Robinson instability. We have first analysed the beam stability criteria in steady state and estimated the transient effect in Feedforward and Feedback RF controls. Initial analytical models for these effects are shown for the design of the JLEIC e-ring from 3GeV to 12GeV.

  15. Fractional laser photothermolysis using Bessel beams

    PubMed Central

    Mignon, Charles; Rodriguez, Aura Higuera; Palero, Jonathan A.; Varghese, Babu; Jurna, Martin

    2016-01-01

    Fractional photothermolysis uses lasers to generate a pattern of microscopic columnar thermal lesions within the skin stimulating collagen remodeling. In this paper we investigate the use of Bessel beams as an alternative to conventional Gaussian beams in creating laser photothermal lesions of different aspect ratios in skin. We show for the first time the improved photothermal lesion depth-to-diameter aspect ratio using Bessel beams in ex vivo human skin as well as in numerical simulations using electric field Monte Carlo photon transport, finite difference methods and Arrhenius model. Bessel beams allow the creation of deep and narrow thermal lesions necessary for improved efficacy in fractional photothermolysis. PMID:28018718

  16. A bubble detection system for propellant filling pipeline

    SciTech Connect

    Wen, Wen; Zong, Guanghua; Bi, Shusheng

    2014-06-15

    This paper proposes a bubble detection system based on the ultrasound transmission method, mainly for probing high-speed bubbles in the satellite propellant filling pipeline. First, three common ultrasonic detection methods are compared and the ultrasound transmission method is used in this paper. Then, the ultrasound beam in a vertical pipe is investigated, suggesting that the width of the beam used for detection is usually smaller than the internal diameter of the pipe, which means that when bubbles move close to the pipe wall, they may escape from being detected. A special device is designed to solve this problem. It can generate the spiral flow to force all the bubbles to ascend along the central line of the pipe. In the end, experiments are implemented to evaluate the performance of this system. Bubbles of five different sizes are generated and detected. Experiment results show that the sizes and quantity of bubbles can be estimated by this system. Also, the bubbles of different radii can be distinguished from each other. The numerical relationship between the ultrasound attenuation and the bubble radius is acquired and it can be utilized for estimating the unknown bubble size and measuring the total bubble volume.

  17. Response of air-filled ion chambers to high-intensity radiation pulses

    SciTech Connect

    Plum, M.; Brown, D.

    1993-06-01

    Ion chambers are one of the most popular types of detectors used for beam loss-monitor systems. To provide a foundation for the development of future loss-monitor systems, and to fully characterize the ion chambers in use at LAMPF, we have studied the response of air-filled cylindrical ion chambers to high-intensity, short-duration radiation pulses. The most intense pulses were about 180 rad in 250 ns (the equivalent steady-state dose rate was about 700 Mrad/h). We filled our chambers with nitrogen gas at 760 Torr and air at 600 Torr. The ion chambers were driven into extreme nonlinear response. We hope these data will be used to design loss-monitor systems based on air-filled ion chambers, thus eliminating the need for gas-flow systems and/or airtight ion chambers.

  18. Response of air-filled ion chambers to high-intensity radiation pulses

    SciTech Connect

    Plum, M.; Brown, D.

    1993-01-01

    Ion chambers are one of the most popular types of detectors used for beam loss-monitor systems. To provide a foundation for the development of future loss-monitor systems, and to fully characterize the ion chambers in use at LAMPF, we have studied the response of air-filled cylindrical ion chambers to high-intensity, short-duration radiation pulses. The most intense pulses were about 180 rad in 250 ns (the equivalent steady-state dose rate was about 700 Mrad/h). We filled our chambers with nitrogen gas at 760 Torr and air at 600 Torr. The ion chambers were driven into extreme nonlinear response. We hope these data will be used to design loss-monitor systems based on air-filled ion chambers, thus eliminating the need for gas-flow systems and/or airtight ion chambers.

  19. Super-long photonic nanojet generated from liquid-filled hollow microcylinder.

    PubMed

    Gu, Guoqiang; Zhou, Rui; Chen, Zaichun; Xu, Huiying; Cai, Guoxiong; Cai, Zhiping; Hong, Minghui

    2015-02-15

    Photonic nanojet (PNJ) from liquid-filled hollow microcylinder (LFHM) under a liquid immersion condition is numerically investigated based on the finite element method and physically analyzed with ray optics. Simulation and analysis results show that, by simultaneously introducing the immersed liquid and filled liquid, the propagation beam is greatly flattened, and super-long PNJs with decay length more than 100 times the illumination wavelengths are obtained in the outer near-field region of the LFHM. With the variation of the refractive index contrast between the filled and immersed-liquids, the properties of the PNJs, such as the focal distance, decay length, full width at half-maximum, and maximum light intensity can be flexibly tuned.

  20. Beam geometry selection using sequential beam addition

    SciTech Connect

    Popple, Richard A. Brezovich, Ivan A.; Fiveash, John B.

    2014-05-15

    Purpose: The selection of optimal beam geometry has been of interest since the inception of conformal radiotherapy. The authors report on sequential beam addition, a simple beam geometry selection method, for intensity modulated radiation therapy. Methods: The sequential beam addition algorithm (SBA) requires definition of an objective function (score) and a set of candidate beam geometries (pool). In the first iteration, the optimal score is determined for each beam in the pool and the beam with the best score selected. In the next iteration, the optimal score is calculated for each beam remaining in the pool combined with the beam selected in the first iteration, and the best scoring beam is selected. The process is repeated until the desired number of beams is reached. The authors selected three treatment sites, breast, lung, and brain, and determined beam arrangements for up to 11 beams from a pool comprised of 25 equiangular transverse beams. For the brain, arrangements were additionally selected from a pool of 22 noncoplanar beams. Scores were determined for geometries comprised equiangular transverse beams (EQA), as well as two tangential beams for the breast case. Results: In all cases, SBA resulted in scores superior to EQA. The breast case had the strongest dependence on beam geometry, for which only the 7-beam EQA geometry had a score better than the two tangential beams, whereas all SBA geometries with more than two beams were superior. In the lung case, EQA and SBA scores monotonically improved with increasing number of beams; however, SBA required fewer beams to achieve scores equivalent to EQA. For the brain case, SBA with a coplanar pool was equivalent to EQA, while the noncoplanar pool resulted in slightly better scores; however, the dose-volume histograms demonstrated that the differences were not clinically significant. Conclusions: For situations in which beam geometry has a significant effect on the objective function, SBA can identify

  1. Filled nanoporous surfaces: controlled formation and wettability.

    PubMed

    Bittoun, Eyal; Marmur, Abraham; Ostblom, Mattias; Ederth, Thomas; Liedberg, Bo

    2009-10-20

    The controlled filling of hydrophobic nanoporous surfaces with hydrophilic molecules and their wetting properties are described and demonstrated by using thiocholesterol (TC) self-assembled monolayers (SAMs) on gold and mercaptoundecanoic acid (MUA) as the filling agent. A novel procedure was developed for filling the nanopores in the TC SAMs by immersing them into a "cocktail" solution of TC and MUA, with TC in huge excess. This procedure results in an increasing coverage of MUA with increasing immersion time up to an area fraction of approximately 23%, while the amount of TC remains almost constant. Our findings strongly support earlier observations where linear omega-substituted alkanethiols selectively fill defects (nanopores) in the TC SAM (Yang et al. Langmuir 1997, 12, 1704-1707). They also support the formation of a homogeneously mixed SAM, given by the distribution of TC on the gold surface, rather than of a phase-segregated overlayer structure with domains of varying size, shape, and composition. The wetting properties of the filled SAMs were investigated by measuring the most stable contact angle as well as contact angle hysteresis. It is shown that the most stable contact angle is very well described by the Cassie equation, since the drops are much larger than the scale of chemical heterogeneity of the SAM surfaces. In addition, it is demonstrated that contact angle hysteresis is sensitive to the chemical heterogeneity of the surface, even at the nanometric scale.

  2. Laser-plasma interactions in large gas-filled hohlraums

    SciTech Connect

    Turner, R.E.; Powers, L.V.; Berger, R.L.

    1996-06-01

    Indirect-drive targets planned for the National Ignition Facility (NIF) laser consist of spherical fuel capsules enclosed in cylindrical Au hohlraums. Laser beams, arranged in cylindrical rings, heat the inside of the Au wall to produce x rays that in turn heat and implode the capsule to produce fusion conditions in the fuel. Detailed calculations show that adequate implosion symmetry can be maintained by filling the hohlraum interior with low-density, low-Z gases. The plasma produced from the heated gas provides sufficient pressure to keep the radiating Au surface from expanding excessively. As the laser heats this gas, the gas becomes a relatively uniform plasma with small gradients in velocity and density. Such long-scale-length plasmas can be ideal mediums for stimulated Brillouin Scattering (SBS). SBS can reflect a large fraction of the incident laser light before it is absorbed by the hohlraum; therefore, it is undesirable in an inertial confinement fusion target. To examine the importance of SBS in NIF targets, the authors used Nova to measure SBS from hohlraums with plasma conditions similar to those predicted for high-gain NIF targets. The plasmas differ from the more familiar exploding foil or solid targets as follows: they are hot (3 keV); they have high electron densities (n{sub e}=10{sup 21}cm{sup {minus}3}); and they are nearly stationary, confined within an Au cylinder, and uniform over large distances (>2 mm). These hohlraums have <3% peak SBS backscatter for an interaction beam with intensities of 1-4 x 10{sup 15} W/cm{sup 2}, a laser wavelength of 0.351{micro}m, f/4 or f/8 focusing optics, and a variety of beam smoothing implementations. Based on these conditions the authors conclude that SBS does not appear to be a problem for NIF targets.

  3. Defect inspection of imprinted 32 nm half pitch patterns

    NASA Astrophysics Data System (ADS)

    Selinidis, Kosta; Thompson, Ecron; McMackin, Ian; Perez, Joseph; Sreenivasan, S. V.; Resnick, Douglas J.

    2008-10-01

    Step and Flash Imprint Lithography redefines nanoimprinting. This novel technique involves the field-by-field deposition and exposure of a low viscosity resist deposited by jetting technology onto the substrate. The patterned mask is lowered into the fluid which then quickly flows into the relief patterns in the mask by capillary action. Following this filling step, the resist is crosslinked under UV radiation, and then the mask is removed leaving a patterned solid on the substrate. Compatibility with existing CMOS processes requires a mask infrastructure in which resolution, inspection and repair are all addressed. The purpose of this paper is to understand the limitations of inspection at half pitches of 32 nm and below. A 32 nm programmed defect mask was fabricated. Patterns included in the mask consisted of an SRAM Metal 1 cell, dense lines, and dense arrays of pillars. Programmed defect sizes started at 4 nm and increased to 48 nm in increments of 4 nm. Defects in both the mask and imprinted wafers were characterized scanning electron microscopy and the measured defect areas were calculated. These defects were then inspected using a KLA-T eS35 electron beam wafer inspection system. Defect sizes as small as 12 nm were detected, and detection limits were found to be a function of defect type.

  4. Laser absorption, power transfer, and radiation symmetry during the first shock of inertial confinement fusion gas-filled hohlraum experiments

    NASA Astrophysics Data System (ADS)

    Pak, A.; Dewald, E. L.; Landen, O. L.; Milovich, J.; Strozzi, D. J.; Berzak Hopkins, L. F.; Bradley, D. K.; Divol, L.; Ho, D. D.; MacKinnon, A. J.; Meezan, N. B.; Michel, P.; Moody, J. D.; Moore, A. S.; Schneider, M. B.; Town, R. P. J.; Hsing, W. W.; Edwards, M. J.

    2015-12-01

    Temporally resolved measurements of the hohlraum radiation flux asymmetry incident onto a bismuth coated surrogate capsule have been made over the first two nanoseconds of ignition relevant laser pulses. Specifically, we study the P2 asymmetry of the incoming flux as a function of cone fraction, defined as the inner-to-total laser beam power ratio, for a variety of hohlraums with different scales and gas fills. This work was performed to understand the relevance of recent experiments, conducted in new reduced-scale neopentane gas filled hohlraums, to full scale helium filled ignition targets. Experimental measurements, matched by 3D view factor calculations, are used to infer differences in symmetry, relative beam absorption, and cross beam energy transfer (CBET), employing an analytic model. Despite differences in hohlraum dimensions and gas fill, as well as in laser beam pointing and power, we find that laser absorption, CBET, and the cone fraction, at which a symmetric flux is achieved, are similar to within 25% between experiments conducted in the reduced and full scale hohlraums. This work demonstrates a close surrogacy in the dynamics during the first shock between reduced-scale and full scale implosion experiments and is an important step in enabling the increased rate of study for physics associated with inertial confinement fusion.

  5. Laser absorption, power transfer, and radiation symmetry during the first shock of inertial confinement fusion gas-filled hohlraum experiments

    SciTech Connect

    Pak, A.; Dewald, E. L.; Landen, O. L.; Milovich, J.; Strozzi, D. J.; Berzak Hopkins, L. F.; Bradley, D. K.; Divol, L.; Ho, D. D.; MacKinnon, A. J.; Meezan, N. B.; Michel, P.; Moody, J. D.; Moore, A. S.; Schneider, M. B.; Town, R. P. J.; Hsing, W. W.; Edwards, M. J.

    2015-12-15

    Temporally resolved measurements of the hohlraum radiation flux asymmetry incident onto a bismuth coated surrogate capsule have been made over the first two nanoseconds of ignition relevant laser pulses. Specifically, we study the P2 asymmetry of the incoming flux as a function of cone fraction, defined as the inner-to-total laser beam power ratio, for a variety of hohlraums with different scales and gas fills. This work was performed to understand the relevance of recent experiments, conducted in new reduced-scale neopentane gas filled hohlraums, to full scale helium filled ignition targets. Experimental measurements, matched by 3D view factor calculations, are used to infer differences in symmetry, relative beam absorption, and cross beam energy transfer (CBET), employing an analytic model. Despite differences in hohlraum dimensions and gas fill, as well as in laser beam pointing and power, we find that laser absorption, CBET, and the cone fraction, at which a symmetric flux is achieved, are similar to within 25% between experiments conducted in the reduced and full scale hohlraums. This work demonstrates a close surrogacy in the dynamics during the first shock between reduced-scale and full scale implosion experiments and is an important step in enabling the increased rate of study for physics associated with inertial confinement fusion.

  6. Patterns of Broken Patterns

    NASA Astrophysics Data System (ADS)

    Field, R. W.; Park, G. B.; Changala, P. B.; Baraban, J. H.; Stanton, J. F.; Merer, A. J.

    2013-06-01

    Spectroscopy - it is all about patterns. Some patterns look so indescribably complicated that, unlike pornography, you do not know one when you see one. It is tempting to say that, at high vibrational excitation, interactions among normal mode basis states are so strong and widespread that all patterns are obliterated. But this is not true. When normal mode frequencies are in near integer multiple ratios, polyads emerge. A polyad is a robust pattern often comprising many vibrational eigenstates. Each such pattern might span many hundreds of cm^{-1}, and it is inevitable that several unrelated polyad patterns overlap. When polyads overlap, it might seem impossible to disentangle them. However, the key to disentanglement is that polyads come in families in which successive generations are related by harmonic oscillator matrix element selection and scaling rules. Families of polyads are described by families of scaling-based effective Hamiltonian matrices, {H}^{{eff}}. No matter how complex and overlapped, the polyad {H}^{{eff}} serves as a magic decoder for picking out the polyad pattern. Sometimes the polyad patterns are systematically broken (a meta-pattern), owing to proximity to an isomerization barrier, as occurs in highly excited bending levels of the S_{1} state of HCCH, which encode the trans-cis minimum energy isomerization path. Quantum Chemists often dismiss {H}^{{eff}} models, precisely because they are models that do not express the full dimensionality of the complete Hamiltonian. But an {H}^{{eff}} explains rather than describes. Shunning {H}^{{eff}}s is like throwing out the baby with the bath water. Don't do it!

  7. Slotted Polyimide-Aerogel-Filled-Waveguide Arrays

    NASA Technical Reports Server (NTRS)

    Rodriguez-Solis, Rafael A.; Pacheco, Hector L.; Miranda, Felix A.; Meador, Mary Ann B.

    2013-01-01

    Polyimide aerogels were considered to serve as a filling for millimeter-wave waveguides. While these waveguides present a slightly higher loss than hollow waveguides, they have less losses than Duroid substrate integrated waveguides (less than 0.15 dB at Ka-band, in a 20 mm section), and exhibit an order of magnitude of mass reduction when compared to commercial waveguides. A Ka-band slotted aerogel-filled-waveguide array was designed, which provided the same gain (9 dBi) as its standard waveguide counterpart, and a slotted aerogel-filled-waveguide array using folded-slots was designed for comparison, obtaining a gain of 9 dB and a bandwidth of 590 MHz.

  8. One-dimensional Gromov minimal filling problem

    NASA Astrophysics Data System (ADS)

    Ivanov, Alexandr O.; Tuzhilin, Alexey A.

    2012-05-01

    The paper is devoted to a new branch in the theory of one-dimensional variational problems with branching extremals, the investigation of one-dimensional minimal fillings introduced by the authors. On the one hand, this problem is a one-dimensional version of a generalization of Gromov's minimal fillings problem to the case of stratified manifolds. On the other hand, this problem is interesting in itself and also can be considered as a generalization of another classical problem, the Steiner problem on the construction of a shortest network connecting a given set of terminals. Besides the statement of the problem, we discuss several properties of the minimal fillings and state several conjectures. Bibliography: 38 titles.

  9. Ultraviolet laser beam monitor using radiation responsive crystals

    DOEpatents

    McCann, Michael P.; Chen, Chung H.

    1988-01-01

    An apparatus and method for monitoring an ultraviolet laser beam includes disposing in the path of an ultraviolet laser beam a substantially transparent crystal that will produce a color pattern in response to ultraviolet radiation. The crystal is exposed to the ultraviolet laser beam and a color pattern is produced within the crystal corresponding to the laser beam intensity distribution therein. The crystal is then exposed to visible light, and the color pattern is observed by means of the visible light to determine the characteristics of the laser beam that passed through crystal. In this manner, a perpendicular cross sectional intensity profile and a longitudinal intensity profile of the ultraviolet laser beam may be determined. The observation of the color pattern may be made with forward or back scattered light and may be made with the naked eye or with optical systems such as microscopes and television cameras.

  10. Development and Commissioning of an External Beam Facility in the Union College Ion Beam Analysis Laboratory

    NASA Astrophysics Data System (ADS)

    Yoskowitz, Joshua; Clark, Morgan; Labrake, Scott; Vineyard, Michael

    2015-10-01

    We have developed an external beam facility for the 1.1-MV tandem Pelletron accelerator in the Union College Ion Beam Analysis Laboratory. The beam is extracted from an aluminum pipe through a 1 / 4 ' ' diameter window with a 7.5- μm thick Kapton foil. This external beam facility allows us to perform ion beam analysis on samples that cannot be put under vacuum, including wet samples and samples too large to fit into the scattering chamber. We have commissioned the new facility by performing proton induced X-ray emission (PIXE) analysis of several samples of environmental interest. These include samples of artificial turf, running tracks, and a human tooth with an amalgam filling. A 1.7-MeV external proton beam was incident on the samples positioned 2 cm from the window. The resulting X-rays were measured using a silicon drift detector and were analyzed using GUPIX software to determine the concentrations of elements in the samples. The results on the human tooth indicate that while significant concentrations of Hg, Ag, and Sn are present in the amalgam filling, only trace amounts of Hg appear to have leached into the tooth. The artificial turf and running tracks show rather large concentrations of a broad range of elements and trace amounts of Pb in the turf infill.

  11. 30 CFR 816.72 - Disposal of excess spoil: Valley fills/head-of-hollow fills.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., 6-hour precipitation event. (b) Rock-core chimney drains. A rock-core chimney drain may be used in a... as the fill is not located in an area containing intermittent or perennial streams. A rock-core... upstream drainage is diverted around the fill. The alternative rock-core chimney drain system shall...

  12. 30 CFR 816.72 - Disposal of excess spoil: Valley fills/head-of-hollow fills.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., 6-hour precipitation event. (b) Rock-core chimney drains. A rock-core chimney drain may be used in a... as the fill is not located in an area containing intermittent or perennial streams. A rock-core... upstream drainage is diverted around the fill. The alternative rock-core chimney drain system shall...

  13. Intermittent Surface Water Connectivity: Fill and Spill vs. Fill and Merge Dynamics

    EPA Science Inventory

    Intermittent surface connectivity can influence aquatic systems, since chemical and biotic movements are often associated with water flow. Although often referred to as fill and spill, wetlands also fill and merge. We examined the effects of these connection types on water level...

  14. Intermittent surface water connectivity: Fill and spill vs. fill and merge dynamics

    USGS Publications Warehouse

    Leibowitz, Scott G.; Mushet, David M.; Newton, Wesley E.

    2016-01-01

    Intermittent surface connectivity can influence aquatic systems, since chemical and biotic movements are often associated with water flow. Although often referred to as fill and spill, wetlands also fill and merge. We examined the effects of these connection types on water levels, ion concentrations, and biotic communities of eight prairie pothole wetlands between 1979 and 2015. Fill and spill caused pulsed surface water connections that were limited to periods following spring snow melt. In contrast, two wetlands connected through fill and merge experienced a nearly continuous, 20-year surface water connection and had completely coincident water levels. Fill and spill led to minimal convergence in dissolved ions and macroinvertebrate composition, while these constituents converged under fill and merge. The primary factor determining differences in response was duration of the surface water connection between wetland pairs. Our findings suggest that investigations into the effects of intermittent surface water connections should not consider these connections generically, but need to address the specific types of connections. In particular, fill and spill promotes external water exports while fill and merge favors internal storage. The behaviors of such intermittent connections will likely be accentuated under a future with more frequent and severe climate extremes.

  15. Alkaline earth filled nickel skutterudite antimonide thermoelectrics

    DOEpatents

    Singh, David Joseph

    2013-07-16

    A thermoelectric material including a body centered cubic filled skutterudite having the formula A.sub.xFe.sub.yNi.sub.zSb.sub.12, where A is an alkaline earth element, x is no more than approximately 1.0, and the sum of y and z is approximately equal to 4.0. The alkaline earth element includes guest atoms selected from the group consisting of Be, Mb, Ca, Sr, Ba, Ra and combinations thereof. The filled skutterudite is shown to have properties suitable for a wide variety of thermoelectric applications.

  16. Experimental study on capillary filling in nanochannels

    NASA Astrophysics Data System (ADS)

    Yang, Min; Cao, Bing-Yang; Wang, Wei; Yun, He-Ming; Chen, Bao-Ming

    2016-10-01

    We investigated the capillary filling kinetics of deionized water in nanochannels with heights of 50-120 nm. The measured position of the moving meniscus was proportional to the square root of time, as predicted by the LW equation. However, the extracted slopes were significantly smaller than the predictions based on the bulk properties. This unusual behavior was found to be mainly caused by the electro-viscous effect and dynamic contact angle, which was significantly larger than the static angle. In addition, when the filling distance reached about 600 μm, bubbles tended to be formed, leading to the main meniscus was almost immobile.

  17. Initial Tests of a Plasma Beam Combiner at NIF

    NASA Astrophysics Data System (ADS)

    Kirkwood, R. K.; Turnbull, D. P.; Chapman, T. D.; Wilks, S. C.; London, R. A.; Berger, R. L.; Michel, P. A.; Divol, L.; Dunlop, W. H.; MacGowan, B. J.; Fournier, K. B.; Blue, B. E.; NIF Team

    2016-10-01

    The seeded forward SBS process that is known to effectively amplify beams in ignition targets has recently been used to design and test a target to combine the power and energy of many beams of the NIF facility into a single beam by intersecting them in an ionized gas. The demand for high-power beams for a variety of applications at NIF makes a demonstration of this process attractive. We will describe experiments using a gas-filled balloon heated by 10 quads of beams, and pumped by additional frequency-tuned quads to amplify a single beam. The beam energy is indicated by gated x-ray images of both the spots produced by the transmitted pump and probe beams and the spot produced by a non-interacting quad of beams when they terminate on a foil. The first experiment produced a high brightness seed beam with significant reductions in brightness of the pumping beams, consistent with their depletion by energy transfer to the seed. Additional experiments studying spot brightness with varying pump power to determine total delivered seed beam energy and power will be discussed as available. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  18. Beam spoiling a reflector antenna with conducting shim.

    SciTech Connect

    Doerry, Armin Walter

    2012-12-01

    A horn-fed dish reflector antenna has characteristics including beam pattern that are a function of its mechanical form. The beam pattern can be altered by changing the mechanical configuration of the antenna. One way to do this is with a reflecting insert or shim added to the face of the original dish.

  19. The structure of filled skutterudites and the local vibration behavior of the filling atom

    NASA Astrophysics Data System (ADS)

    Zhou, Xiaojuan; Zong, Peng-an; Chen, Xihong; Tao, Juzhou; Lin, He

    2017-02-01

    Both of atomic pair distribution function (PDF) and extended x-ray absorption fine structure (EXAFS) experiments have been carried out on unfilled and Yb-filled skutterudites YbxCo4Sb12 (x=0, 0.15, 0.2 and 0.25) samples. The structure refinements on PDF data confirm the large amplitude vibration of Yb atom and the dependence of Yb vibration amplitude on the filling content. Temperature dependent EXAFS experiment on filled skutterudites have been carried out at Yb LⅢ-edge in order to explore the local vibration behavior of filled atom. EXAFS experiments show that the Einstein temperature of the filled atom is very low (70.9 K) which agrees with the rattling behavior.

  20. Young's Interference Experiment with Electron Beams Carrying Orbital Angular Momentum

    NASA Astrophysics Data System (ADS)

    Hasegawa, Yuya; Saitoh, Koh; Tanaka, Nobuo; Tanimura, Shogo; Uchida, Masaya

    2013-03-01

    A Young's-type double-slit experiment using electron beams carrying orbital angular momentum (OAM) is demonstrated in a transmission electron microscope. Each of the slits is replaced by a grating mask with a fork dislocation, which generates electron beams with OAM as diffracted beams. Interference fringes produced by two diffracted electron beams with OAM appear at the observation screen. The interference fringe patterns exhibit dislocation features depending on the topological charges of the two electron beams. The experimental results clearly show the wave nature of the electron beams with OAM and gives potential applications in electron physics and quantum mechanics.

  1. Method and apparatus for timing of laser beams in a multiple laser beam fusion system

    DOEpatents

    Eastman, Jay M.; Miller, Theodore L.

    1981-01-01

    The optical path lengths of a plurality of comparison laser beams directed to impinge upon a common target from different directions are compared to that of a master laser beam by using an optical heterodyne interferometric detection technique. The technique consists of frequency shifting the master laser beam and combining the master beam with a first one of the comparison laser beams to produce a time-varying heterodyne interference pattern which is detected by a photo-detector to produce an AC electrical signal indicative of the difference in the optical path lengths of the two beams which were combined. The optical path length of this first comparison laser beam is adjusted to compensate for the detected difference in the optical path lengths of the two beams. The optical path lengths of all of the comparison laser beams are made equal to the optical path length of the master laser beam by repeating the optical path length adjustment process for each of the comparison laser beams. In this manner, the comparison laser beams are synchronized or timed to arrive at the target within .+-.1.times.10.sup.-12 second of each other.

  2. The Fill-In Effect in Serial Recall Can Be Obscured by Omission Errors

    ERIC Educational Resources Information Center

    Osth, Adam F.; Dennis, Simon

    2015-01-01

    Henson (1996) provided a number of demonstrations of error patterns in serial recall that contradict chaining models. Chaining models predict that when participants erroneously recall an item too early, recall should proceed from the point of error. In contradiction to such a prediction, Henson found evidence for a fill-in effect: participants…

  3. In-Situ Real Time Monitoring and Control of Mold Making and Filling Processes

    SciTech Connect

    2004-11-01

    This factsheet describes a research effort to develop an innovative approach to introduce technologies for real-time characterization of sand molds, lost foam patterns, and monitoring of the mold filling process. This will reduce scrap, improve product quality, and save energy.

  4. Standardized beam bouquets for lung IMRT planning

    NASA Astrophysics Data System (ADS)

    Yuan, Lulin; Wu, Q. Jackie; Yin, Fangfang; Li, Ying; Sheng, Yang; Kelsey, Christopher R.; Ge, Yaorong

    2015-02-01

    The selection of the incident angles of the treatment beams is a critical component of intensity modulated radiation therapy (IMRT) planning for lung cancer due to significant variations in tumor location, tumor size and patient anatomy. We investigate the feasibility of establishing a small set of standardized beam bouquets for planning. The set of beam bouquets were determined by learning the beam configuration features from 60 clinical lung IMRT plans designed by experienced planners. A k-medoids cluster analysis method was used to classify the beam configurations in the dataset. The appropriate number of clusters was determined by maximizing the value of average silhouette width of the classification. Once the number of clusters had been determined, the beam arrangements in each medoid of the clusters were designated as the standardized beam bouquet for the cluster. This standardized bouquet set was used to re-plan 20 cases randomly selected from the clinical database. The dosimetric quality of the plans using the beam bouquets was evaluated against the corresponding clinical plans by a paired t-test. The classification with six clusters has the largest average silhouette width value and hence would best represent the beam bouquet patterns in the dataset. The results shows that plans generated with a small number of standardized bouquets (e.g. 6) have comparable quality to that of clinical plans. These standardized beam configuration bouquets will potentially help improve plan efficiency and facilitate automated planning.

  5. E-Beam Written Computer Generated Holograms.

    DTIC Science & Technology

    1983-08-01

    interferometer . Figure 3-2 is an ex- ploded view depicting all the optical elements. Basically, the instrument is a Twyman -Green interferometer in which...to Measure E-Beam 24 Pattern Distortion 2-3 Diffraction Pattern of the Crossed Grating 2-5 24 Interferometer Arrangement for Measuring E-Beam Pattern... Interferometer in Operation 3-2 An Exploded View of the Honeywell/Tropel Holographic 3-3 and Shearing Interferometer Showing All the Optical Elements 3-3 E

  6. Cotton-Fiber-Filled Rubber Insulation

    NASA Technical Reports Server (NTRS)

    Anderson, Floyd A.

    1987-01-01

    Carbonization of fibers at high temperatures improves strength and erosion resistance. Cotton linters tested as replacement for asbestos filler currently used in rubber insulation in solid rocket motors. Cotton-filled rubber insulation has industrial uses; in some kinds of chemical- or metal-processing equipment, hoses, and protective clothing.

  7. 7 CFR 58.730 - Filling containers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Procedures § 58.730 Filling containers. Hot fluid cheese from the cookers may be held in hotwells or hoppers to assure a constant and even supply of processed cheese to the filler or slice former. Filler valves... and shall cut off sharply without drip or drag of cheese across the opening. An effective system...

  8. Banach spaces that realize minimal fillings

    NASA Astrophysics Data System (ADS)

    Bednov, B. B.; Borodin, P. A.

    2014-04-01

    It is proved that a real Banach space realizes minimal fillings for all its finite subsets (a shortest network spanning a fixed finite subset always exists and has the minimum possible length) if and only if it is a predual of L_1. The spaces L_1 are characterized in terms of Steiner points (medians). Bibliography: 25 titles.

  9. Irregularly Shaped Space-Filling Truncated Octahedra

    ERIC Educational Resources Information Center

    Hanson, John Robert

    2008-01-01

    For any parent tetrahedron ABCD, centroids of selected sub-tetrahedra form the vertices of an irregularly shaped space-filling truncated octahedron. To reflect these properties, such a figure will be called an ISTO. Each edge of the ISTO is parallel to and one-eighth the length of one of the edges of tetrahedron ABCD and the volume of the ISTO is…

  10. The Chemistry of Modern Dental Filling Materials.

    ERIC Educational Resources Information Center

    Nicholson, John W.; Anstice, H. Mary

    1999-01-01

    Discusses materials used by dentists to restore teeth after decay has been removed. Shows how dental-material science is an interdisciplinary field in which chemistry plays a major part. Reviews the many developments polymer chemistry has contributed to the field of dental fillings. (CCM)

  11. SOIL AND FILL LABORATORY SUPPORT - 1991

    EPA Science Inventory

    The report gives results of soil analysis laboratory work by the University of Florida in Support of the Florida Radon Research Program (FRRP). Analyses were performed on soil and fill samples collected during 1991 by the FRRP Research House program and the New House Evaluation P...

  12. Banach spaces that realize minimal fillings

    SciTech Connect

    Bednov, B. B.; Borodin, P. A. E-mail: pborodin@inbox.ru

    2014-04-30

    It is proved that a real Banach space realizes minimal fillings for all its finite subsets (a shortest network spanning a fixed finite subset always exists and has the minimum possible length) if and only if it is a predual of L{sub 1}. The spaces L{sub 1} are characterized in terms of Steiner points (medians). Bibliography: 25 titles. (paper)

  13. 5 CFR 362.203 - Filling positions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... applications from individuals outside its own workforce, it must provide OPM information concerning... position, and (iii) How to apply. A public source (e.g., a link to the agency's Web site with information... subject-matter expertise, or to fill traditional summer jobs. The agency may extend these...

  14. 5 CFR 362.203 - Filling positions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... applications from individuals outside its own workforce, it must provide OPM information concerning... position, and (iii) How to apply. A public source (e.g., a link to the agency's Web site with information... subject-matter expertise, or to fill traditional summer jobs. The agency may extend these...

  15. Biomineral nanoparticles are space-filling

    NASA Astrophysics Data System (ADS)

    Yang, Li; Killian, Christopher E.; Kunz, Martin; Tamura, Nobumichi; Gilbert, P. U. P. A.

    2011-02-01

    Sea urchin biominerals have been shown to form from aggregating nanoparticles of amorphous calcium carbonate (ACC), which then crystallize into macroscopic single crystals of calcite. Here we measure the surface areas of these biominerals and find them to be comparable to those of space-filling macroscopic geologic calcite crystals. These biominerals differ from synthetic mesocrystals, which are invariably porous. We propose that space-filling ACC is the structural precursor for echinoderm biominerals.Sea urchin biominerals have been shown to form from aggregating nanoparticles of amorphous calcium carbonate (ACC), which then crystallize into macroscopic single crystals of calcite. Here we measure the surface areas of these biominerals and find them to be comparable to those of space-filling macroscopic geologic calcite crystals. These biominerals differ from synthetic mesocrystals, which are invariably porous. We propose that space-filling ACC is the structural precursor for echinoderm biominerals. This article was submitted as part of a Themed Issue on Crystallization and Formation Mechanisms of Nanostructures. Other papers on this topic can be found in issue 11 of vol. 2 (2010). This issue can be found from the Nanoscale homepage [http://www.rsc.org/nanoscale

  16. Thermotropic nematic order upon nanocapillary filling

    NASA Astrophysics Data System (ADS)

    Huber, Patrick; Busch, Mark; Całus, Sylwia; Kityk, Andriy V.

    2013-04-01

    Optical birefringence and light absorption measurements reveal four regimes for the thermotropic behavior of a nematogen liquid (7CB) upon sequential filling of parallel-aligned capillaries of 12 nm diameter in a monolithic, mesoporous silica membrane. No molecular reorientation is observed for the first adsorbed monolayer. In the film-condensed state (up to 1 nm thickness), a weak, continuous paranematic-to-nematic (P-N) transition is found, which is shifted by 10 K below the discontinuous bulk transition at TIN=305 K. The capillary-condensed state exhibits a more pronounced, albeit still continuous P-N reordering, located 4 K below TIN. This shift vanishes abruptly upon complete filling of the capillaries. It could originate in competing anchoring conditions at the free inner surfaces and at the pore walls or result from the 10-MPa tensile pressure release associated with the disappearance of concave menisci in the confined liquid upon complete filling. The study documents that the thermo-optical properties of nanoporous systems (or single nanocapillaries) can be tailored over a surprisingly wide range simply by variation of the filling fraction with liquid crystals.

  17. New Skeletal-Space-Filling Models

    ERIC Educational Resources Information Center

    Clarke, Frank H.

    1977-01-01

    Describes plastic, skeletal molecular models that are color-coded and can illustrate both the conformation and overall shape of small molecules. They can also be converted to space-filling counterparts by the additions of color-coded polystyrene spheres. (MLH)

  18. Postscript: Filling-in Models of Completion

    ERIC Educational Resources Information Center

    Anderson, Barton L.

    2007-01-01

    Presents some additional comments from the current author regarding his original article "Filling-in models of completion: Rejoinder to Kellman, Garrigan, Shipley, and Keane (2007) and Albert (2007)." Despite repeated assertions by Kellman et al., I have never claimed that luminance constraints block modal completion; rather, they merely weaken…

  19. 27 CFR 19.360 - Filling packages.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Filling packages. 19.360 Section 19.360 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL DISTILLED SPIRITS PLANTS Processing of Distilled Spirits Rules for...

  20. 27 CFR 19.390 - Filling packages.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Filling packages. 19.390 Section 19.390 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS DISTILLED SPIRITS PLANTS Processing Operations Other Than Denaturation...

  1. 27 CFR 19.360 - Filling packages.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Filling packages. 19.360 Section 19.360 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS DISTILLED SPIRITS PLANTS Processing of Distilled Spirits Rules for...

  2. 27 CFR 19.360 - Filling packages.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Filling packages. 19.360 Section 19.360 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL DISTILLED SPIRITS PLANTS Processing of Distilled Spirits Rules for...

  3. 27 CFR 19.360 - Filling packages.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Filling packages. 19.360 Section 19.360 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS DISTILLED SPIRITS PLANTS Processing of Distilled Spirits Rules for...

  4. Evaluation of CP shape correction for e-beam writing

    NASA Astrophysics Data System (ADS)

    Takizawa, Masahiro; Bunya, Keita; Isobe, Hideaki; Komami, Hideaki; Abe, Kenji; Kurokawa, Masaki; Yamada, Akio; Sakamoto, Kiichi; Nakamura, Takayuki; Kuwano, Kazusumi; Tateishi, Masahiro; Chau, Larry

    2012-11-01

    Character projection (CP) exposure has some advantages compared with variable shaped beam (VSB) system; (1) shot count reduction by printing complex patterns in one e-beam shot, (2) high pattern fidelity by using CP stencil. In this paper we address another advantage of CP exposure, namely the shape correction of CP stencil for cancelling the pattern deformation on the substrate. The deformation of CP printings is decomposed into some elements. They are CP stencil manufacturing error, proximity effect, beam blur of the e-beam writer and resist blur. The element caused by beam blur of e-beam writer can be predicted by measuring the total beam blur obtained from CD-dose curves. The pattern deformation was corrected by applying the shape correction software system of D2S. The corrected CP stencil of 22nm-node standard cell was manufactured and standard cell patterns were exposed. We confirmed that our shape correction method is the appropriate solution for correcting deformation issue of CP openings. The beam blur required for the 1X nm dimensions was predicted from the exposure results of standard cell patterns with applying shape correction and CD-dose curves. We simulated the optical system to realize the required beam blur. As a result, the next electron optics has the resolving capability of 1X nm dimension.

  5. Relativistic electron beam generator

    DOEpatents

    Mooney, L.J.; Hyatt, H.M.

    1975-11-11

    A relativistic electron beam generator for laser media excitation is described. The device employs a diode type relativistic electron beam source having a cathode shape which provides a rectangular output beam with uniform current density.

  6. Laser beam monitoring system

    DOEpatents

    Weil, Bradley S.; Wetherington, Jr., Grady R.

    1985-01-01

    Laser beam monitoring systems include laser-transparent plates set at an angle to the laser beam passing therethrough and light sensor for detecting light reflected from an object on which the laser beam impinges.

  7. Numerical recipes for mold filling simulation

    SciTech Connect

    Kothe, D.; Juric, D.; Lam, K.; Lally, B.

    1998-07-01

    Has the ability to simulate the filling of a mold progressed to a point where an appropriate numerical recipe achieves the desired results? If results are defined to be topological robustness, computational efficiency, quantitative accuracy, and predictability, all within a computational domain that faithfully represents complex three-dimensional foundry molds, then the answer unfortunately remains no. Significant interfacial flow algorithm developments have occurred over the last decade, however, that could bring this answer closer to maybe. These developments have been both evolutionary and revolutionary, will continue to transpire for the near future. Might they become useful numerical recipes for mold filling simulations? Quite possibly. Recent progress in algorithms for interface kinematics and dynamics, linear solution methods, computer science issues such as parallelization and object-oriented programming, high resolution Navier-Stokes (NS) solution methods, and unstructured mesh techniques, must all be pursued as possible paths toward higher fidelity mold filling simulations. A detailed exposition of these algorithmic developments is beyond the scope of this paper, hence the authors choose to focus here exclusively on algorithms for interface kinematics. These interface tracking algorithms are designed to model the movement of interfaces relative to a reference frame such as a fixed mesh. Current interface tracking algorithm choices are numerous, so is any one best suited for mold filling simulation? Although a clear winner is not (yet) apparent, pros and cons are given in the following brief, critical review. Highlighted are those outstanding interface tracking algorithm issues the authors feel can hamper the reliable modeling of today`s foundry mold filling processes.

  8. Filling the blanks in temporal intervals: the type of filling influences perceived duration and discrimination performance

    PubMed Central

    Horr, Ninja K.; Di Luca, Massimiliano

    2015-01-01

    In this work we investigate how judgments of perceived duration are influenced by the properties of the signals that define the intervals. Participants compared two auditory intervals that could be any combination of the following four types: intervals filled with continuous tones (filled intervals), intervals filled with regularly-timed short tones (isochronous intervals), intervals filled with irregularly-timed short tones (anisochronous intervals), and intervals demarcated by two short tones (empty intervals). Results indicate that the type of intervals to be compared affects discrimination performance and induces distortions in perceived duration. In particular, we find that duration judgments are most precise when comparing two isochronous and two continuous intervals, while the comparison of two anisochronous intervals leads to the worst performance. Moreover, we determined that the magnitude of the distortions in perceived duration (an effect akin to the filled duration illusion) is higher for tone sequences (no matter whether isochronous or anisochronous) than for continuous tones. Further analysis of how duration distortions depend on the type of filling suggests that distortions are not only due to the perceived duration of the two individual intervals, but they may also be due to the comparison of two different filling types. PMID:25717310

  9. Beam imaging sensor

    DOEpatents

    McAninch, Michael D.; Root, Jeffrey J.

    2016-07-05

    The present invention relates generally to the field of sensors for beam imaging and, in particular, to a new and useful beam imaging sensor for use in determining, for example, the power density distribution of a beam including, but not limited to, an electron beam or an ion beam. In one embodiment, the beam imaging sensor of the present invention comprises, among other items, a circumferential slit that is either circular, elliptical or polygonal in nature.

  10. Tunable beam displacer

    SciTech Connect

    Salazar-Serrano, Luis José; Valencia, Alejandra; Torres, Juan P.

    2015-03-15

    We report the implementation of a tunable beam displacer, composed of a polarizing beam splitter (PBS) and two mirrors, that divides an initially polarized beam into two parallel beams whose separation can be continuously tuned. The two output beams are linearly polarized with either vertical or horizontal polarization and no optical path difference is introduced between them. The wavelength dependence of the device as well as the maximum separation between the beams achievable is limited mainly by the PBS characteristics.

  11. Profiling structured beams using injected aerosols

    NASA Astrophysics Data System (ADS)

    Loh, N. D.; Starodub, Dmitri; Lomb, Lukas; Hampton, Christina Y.; Martin, Andrew V.; Sierra, Raymond G.; Barty, Anton; Aquila, Andrew; Schulz, Joachim; Steinbrener, Jan; Shoeman, Robert L.; Kassemeyer, Stephan; Bostedt, Christoph; Bozek, John; Epp, Sascha W.; Erk, Benjamin; Hartmann, Robert; Rolles, Daniel; Rudenko, Artem; Rudek, Benedikt; Foucar, Lutz; Kimmel, Nils; Weidenspointner, Georg; Hauser, Günther; Holl, Peter; Pedersoli, Emanuele; Liang, MengNing; Hunter, Mark S.; Gumprecht, Lars; Coppola, Nicola; Wunderer, Cornelia; Graafsman, Heinz; Maia, Filipe R. N. C.; Ekeberg, Tomas; Hantke, Max; Fleckenstein, Holger; Hirsemann, Helmut; Nass, Karol; White, Thomas A.; Tobias, Herbert J.; Farquar, George R.; Benner, W. Henry; Hau-Riege, Stefan; Reich, Christian; Hartmann, Andreas; Soltau, Heike; Marchesini, Stefano; Bajt, Sasa; Barthelmess, Miriam; Strueder, Lothar; Ullrich, Joachim; Bucksbaum, Philip; Hodgson, Keith O.; Frank, Mathias; Schlichting, Ilme; Chapman, Henry N.; Bogan, Michael J.

    2012-10-01

    Profiling structured beams produced by X-ray free-electron lasers (FELs) is crucial to both maximizing signal intensity for weakly scattering targets and interpreting their scattering patterns. Earlier ablative imprint studies describe how to infer the X-ray beam profile from the damage that an attenuated beam inflicts on a substrate. However, the beams in-situ profile is not directly accessible with imprint studies because the damage profile could be different from the actual beam profile. On the other hand, although a Shack-Hartmann sensor is capable of in-situ profiling, its lenses may be quickly damaged at the intense focus of hard X-ray FEL beams. We describe a new approach that probes the in-situ morphology of the intense FEL focus. By studying the translations in diffraction patterns from an ensemble of randomly injected sub-micron latex spheres, we were able to determine the non-Gaussian nature of the intense FEL beam at the Linac Coherent Light Source (SLAC National Laboratory) near the FEL focus. We discuss an experimental application of such a beam-profiling technique, and the limitations we need to overcome before it can be widely applied.

  12. BEAM INSTRUMENTATION FOR HIGH POWER HADRON BEAMS

    SciTech Connect

    Aleksandrov, Alexander V

    2013-01-01

    This presentation will describe developments in the beam diagnostics which support the understanding and operation of high power hadron accelerators. These include the measurement of large dynamic range transverse and longitudinal beam profiles, beam loss detection, and non-interceptive diagnostics.

  13. Propagation-invariant beams with quantum pendulum spectra: from Bessel beams to Gaussian beam-beams.

    PubMed

    Dennis, Mark R; Ring, James D

    2013-09-01

    We describe a new class of propagation-invariant light beams with Fourier transform given by an eigenfunction of the quantum mechanical pendulum. These beams, whose spectra (restricted to a circle) are doubly periodic Mathieu functions in azimuth, depend on a field strength parameter. When the parameter is zero, pendulum beams are Bessel beams, and as the parameter approaches infinity, they resemble transversely propagating one-dimensional Gaussian wave packets (Gaussian beam-beams). Pendulum beams are the eigenfunctions of an operator that interpolates between the squared angular momentum operator and the linear momentum operator. The analysis reveals connections with Mathieu beams, and insight into the paraxial approximation.

  14. Factors affecting opening and filling pressures in the lungs of the lizard Pogona vitticeps.

    PubMed

    Wood, P G; Daniels, C B

    1996-02-01

    We have previously reported that levels of pulmonary surfactant in the lungs of the lizard Pogona vitticeps increase with increasing body temperature. Static lung compliance decreases with increasing body temperature, and is only marginally affected by the presence of surfactant. Here, we examined the effects of surfactant, temperature, ventilatory pattern and autonomic neurotransmitters on opening and filling pressures. Isolated lungs were ventilated at either 18 or 37 degrees C at low, intermediate and high ventilatory regimes. The effects of acetylcholine and adrenaline were examined using an isolated perfused lung preparation at 27 degrees C. Changing ventilatory pattern or experimental temperature had no effect on either filling or opening pressures. Removal of surfactant increased both opening and filling pressures. Adrenaline administration reduced opening and filling pressures. Normal variations in surfactant levels, which occur with changes in body temperature, do not affect either opening or filling pressures. A critical amount of surfactant may be necessary to prevent adhesion of epithelial surfaces in the lungs of Pogona vitticeps. The anti-glue function of pulmonary surfactant may be more important at 18 than at 37 degrees C.

  15. SEMICONDUCTOR TECHNOLOGY Dummy fill effect on CMP planarity

    NASA Astrophysics Data System (ADS)

    Junxiong, Zhou; Lan, Chen; Wenbiao, Ruan; Zhigang, Li; Weixiang, Shen; Tianchun, Ye

    2010-10-01

    With the use of a chemical-mechanical polishing (CMP) simulator verified by testing data from a foundry, the effect of dummy fill characteristics, such as fill size, fill density and fill shape, on CMP planarity is analyzed. The results indicate that dummy density has a significant impact on oxide erosion, and copper dishing is in proportion to dummy size. We also demonstrate that cross shape dummy fill can have the best dishing performance at the same density.

  16. Chaos and Beyond in a Water Filled Ultrasonic Resonance System

    NASA Technical Reports Server (NTRS)

    Lazlo, Adler; Yost, W.; Cantrell, John H.

    2013-01-01

    Finite amplitude ultrasonic wave resonances in a one-dimensional liquid-filled cavity, formed by a narrow band transducer and a plane reflector, are reported. The resonances are observed to include not only the expected harmonic and subharmonic signals (1,2) but chaotic signals as well. The generation mechanism requires attaining a threshold value of the driving amplitude that the liquid-filled cavity system becomes sufficiently nonlinear in response. The nonlinear features of the system were recently investigated via the construction of an ultrasonic interferometer having optical precision. The transducers were compressional, undamped quartz and lithium niobate crystals having the frequency range 1-10 MHz, driven by a high power amplifier. Both an optical diffraction system to characterize the diffraction pattern of laser light normally incident to the cavity and a receiving transducer attached to an aligned reflector with lapped flat and parallel surfaces were used to assess the generated resonance response in the cavity. At least 5 regions of excitation are identified.

  17. Preliminary Study on Water Filled Tank Perforation by Rod Projectiles

    NASA Astrophysics Data System (ADS)

    Xiao, Xin-Ke; Guo, Zi-Tao; Mu, Zhong-Cheng; Zhang, Wei

    2009-06-01

    The effects of fluid structure interactions resulting from the impact of a fluid filled tank is of the interests for engineers from both the military and civilian field, where hydrodynamic-ram (HRAM) phenomena is well known. And it is believed HRAM is responsible for the vulnerability and the possible catastrophic failure of the whole tank. Thus HRAM is related to the majority concerns on this topic, where the targets were usually assumed to be thin. In order to investigate the influence of water on the crashworthiness of a tank with relatively thick walls, 3 ballistic shots on the water filled tank with two 3 mm 2A12 aluminum plates as front and back target and 4 shots on the tank without any water by 12.7 mm rods were conducted. The failure patterns were indentified from the tests and the difference in the failure mechanism was further studied by a series of detailed numerical simulations on the corresponding tests in hydro-code AUTODYN-2D by using both the coupled Lagrange-Euler technology and the SPH method. And also, the challenge of numerical simulation in this field is addressed.

  18. Shock-wave dynamics during oil-filled transformer explosions

    NASA Astrophysics Data System (ADS)

    Efremov, V. P.; Ivanov, M. F.; Kiverin, A. D.; Utkin, A. V.

    2016-08-01

    This paper presents a numerical and experimental study of the shock-wave processes evolving inside a closed vessel filled with mineral oil. Obtained experimental Hugoniot data for oil are compared with the corresponding data for water. It is found that compression of mineral oil and water can be described by approximately the same Hugoniot over a wide pressure range. Such similarity allows the use of water instead of mineral oil in the transformer explosion experiments and to describe the compression processes in both liquids using similar equations of state. The Kuznetsov equation of state for water is adopted for a numerical study of mineral oil compression. The features of the evolution of shock waves within mineral oil are analyzed using two-dimensional numerical simulations. Numerical results show that different energy sources may cause different scenarios of loading on the shell. The principal point is the phase transition taking place at relatively high temperatures for the case of high-power energy sources. In this case, a vapor-gaseous bubble emerges that qualitatively changes the dynamics of compression waves and the pattern of loads induced on the shell. Taking into account the features of the process together with the concept of water-oil similarity, the present work presents a new approach for experimental modeling of transformer shell destruction using an explosion with given characteristics in a water-filled shell.

  19. Pressurized rf cavities in ionizing beams

    NASA Astrophysics Data System (ADS)

    Freemire, B.; Tollestrup, A. V.; Yonehara, K.; Chung, M.; Torun, Y.; Johnson, R. P.; Flanagan, G.; Hanlet, P. M.; Collura, M. G.; Jana, M. R.; Leonova, M.; Moretti, A.; Schwarz, T.

    2016-06-01

    A muon collider or Higgs factory requires significant reduction of the six dimensional emittance of the beam prior to acceleration. One method to accomplish this involves building a cooling channel using high pressure gas filled radio frequency cavities. The performance of such a cavity when subjected to an intense particle beam must be investigated before this technology can be validated. To this end, a high pressure gas filled radio frequency (rf) test cell was built and placed in a 400 MeV beam line from the Fermilab linac to study the plasma evolution and its effect on the cavity. Hydrogen, deuterium, helium and nitrogen gases were studied. Additionally, sulfur hexafluoride and dry air were used as dopants to aid in the removal of plasma electrons. Measurements were made using a variety of beam intensities, gas pressures, dopant concentrations, and cavity rf electric fields, both with and without a 3 T external solenoidal magnetic field. Energy dissipation per electron-ion pair, electron-ion recombination rates, ion-ion recombination rates, and electron attachment times to SF6 and O2 were measured.

  20. Numerical Investigation of the Effect of the Location of Critical Rock Block Fracture on Crack Evolution in a Gob-side Filling Wall

    NASA Astrophysics Data System (ADS)

    Li, Xuehua; Ju, Minghe; Yao, Qiangling; Zhou, Jian; Chong, Zhaohui

    2016-03-01

    Generation, propagation, and coalescence of the shear and tensile cracks in the gob-side filling wall are significantly affected by the location of the fracture of the critical rock block. The Universal Discrete Element Code software was used to investigate crack evolution characteristics in a gob-side filling wall and the parameter calibration process for various strata and the filling wall was clearly illustrated. The cracks in both the filling wall and the coal wall propagate inward in a V-shape pattern with dominant shear cracks generated initially. As the distance between the fracture and the filling wall decreases, the number of cracks in the filling wall decreases, and the stability of the filling wall gradually improves; thus, by splitting the roof rock at the optimal location, the filling wall can be maintained in a stable state. Additionally, we conducted a sensitivity analysis that demonstrated that the higher the coal seam strength, the fewer cracks occur in both the filling wall and the coal wall, and the less failure they experience. With the main roof fracturing into a cantilever structure, the higher the immediate roof strength, the fewer cracks are in the filling wall. With the critical rock block fracturing above the roadway, an optimal strength of the immediate roof can be found that will stabilize the filling wall. This study presents a theoretical investigation into stabilization of the filling wall, demonstrating the significance of pre-splitting the roof rock at a desirable location.

  1. Multiple beam laser cell micropatterning system

    NASA Astrophysics Data System (ADS)

    Narasimhan, Sriram V.; Goodwin, Richard L.; Borg, Thomas K.; Dawson, Darren M.; Gao, Bruce Z.

    2004-10-01

    The various cell mechanisms, including cell-cell interactions, in native tissue could be better understood by engineering a cell coculture with a micro environment that closely mimics the natural cell arrangement. To this end, we developed a cell micropatterning system that uses a weakly focused laser beam to trap individual cells at the center of the beam and propel them forward onto an appropriate substrate. The optimal methods of introducing different cell types to be patterned into the patterning system and preventing cells from randomly falling onto the pattern were issues to be addressed with this system. Here, we report the development of a multi-chamber, multi-beam laser cell micropatterning system, in which the delivery of specific cells into the beam can be controlled using secondary laser beams. This permits consecutive creation of a pattern involving multiple cell types at specific relative positions. As examples, various patterns of fibroblasts have been created on collagen coated coverslips. In addition, two asynchronously beating clusters of cardiomyocytes were connected with fibroblasts of cardiac origin, yielding a deeper insight into the electrophysiological role of fibroblasts in conduction of the action potentials among cardiomyocytes.

  2. Low-intensity lasers, modern filling materials, and bonding systems influence on mineral metabolism of hard dental tissues

    NASA Astrophysics Data System (ADS)

    Kunin, Anatoly A.; Yesaulenko, I. E.; Zoibelmann, M.; Pankova, Svetlana N.; Ippolitov, Yu. A.; Oleinik, Olga I.; Popova, T. A.; Koretskaya, I. V.; Shumilovitch, Bogdan R.; Podolskaya, Elana E.

    2001-10-01

    One of the main reasons of low quality filling is breaking Ca-P balance in hard tissues. Our research was done with the purpose of studying the influence of low intensity lasers, diodic radiation, the newest filling and bonding systems on the processes of mineral metabolism in hard dental tissues while filling a tooth. 250 patients having caries and its compli-cations were examined and treated. Our complex research included: visual and instrumental examination, finding out the level of oral cavity hygiene, acid enamel biopsy, scanning electronic microscopy and X-ray spectrum microanalysis. Filling processes may produce a negative effect on mineral metabolism of hard dental tissues the latter is less pronounced when applying fluoride-containing filling materials with bonding systems. It has also been found that bonding dentin and enamel systems are designed for both a better filling adhesion (i.e. mechanical adhesion) and migration of useful microelements present in them by their sinking into hard dental tissues (i.e. chemical adhesion). Our research showed a positive influence of low intensity laser and diodic beams accompanying the use of modern filling and bonding systems on mineral metabolism of hard dental tissues.

  3. Maskless, resistless ion beam lithography

    SciTech Connect

    Ji, Qing

    2003-01-01

    As the dimensions of semiconductor devices are scaled down, in order to achieve higher levels of integration, optical lithography will no longer be sufficient for the needs of the semiconductor industry. Alternative next-generation lithography (NGL) approaches, such as extreme ultra-violet (EUV), X-ray, electron-beam, and ion projection lithography face some challenging issues with complicated mask technology and low throughput. Among the four major alternative NGL approaches, ion beam lithography is the only one that can provide both maskless and resistless patterning. As such, it can potentially make nano-fabrication much simpler. This thesis investigates a focused ion beam system for maskless, resistless patterning that can be made practical for high-volume production. In order to achieve maskless, resistless patterning, the ion source must be able to produce a variety of ion species. The compact FIB system being developed uses a multicusp plasma ion source, which can generate ion beams of various elements, such as O2+, BF2+, P+ etc., for surface modification and doping applications. With optimized source condition, around 85% of BF2+, over 90% of O2+ and P+ have been achieved. The brightness of the multicusp-plasma ion source is a key issue for its application to maskless ion beam lithography. It can be substantially improved by optimizing the source configuration and extractor geometry. Measured brightness of 2 keV He+ beam is as high as 440 A/cm2 • Sr, which represents a 30x improvement over prior work. Direct patterning of Si thin film using a focused O2+ ion beam has been investigated. A thin surface oxide film can be selectively formed using 3 keV O2+ ions with the dose of 1015 cm-2. The oxide can then serve as a hard mask for patterning of the Si film. The

  4. Microwave permeability of composites filled with thin Fe films

    NASA Astrophysics Data System (ADS)

    Iakubov, Igor T.; Lagarkov, Andrey N.; Maklakov, Sergey A.; Osipov, Alexey V.; Rozanov, Konstantin N.; Ryzhikov, Ilya A.; Starostenko, Sergey N.

    2006-05-01

    The microwave permeability of regular composites filled with thin ferromagnetic discs with in-plane anisotropy is studied. The samples are made of patterned, multi-layered Fe films stacked together to comprise a bulk composite. The permeability is measured in the frequency range of 0.1-10 GHz, and is discussed in terms of constraints to the microwave performance of such composites. The technology suggested allows a composite sample to be produced with the permeability of 2.8, and low magnetic loss at frequencies below 1 GHz, the volume fraction of Fe is as low as 0.77%. Such composites can be useful in the design of microwave inductors, miniaturized wideband antennas, etc.

  5. Paradoxical form of filled/empty optical illusion.

    PubMed

    Wackermann, Jiri; Kastner, Kristina

    2009-01-01

    The filled/empty illusion (Oppel-Kundt) is one of the oldest geometrical-optical illusions, but the determinants of the illusion are not yet sufficiently understood. We studied magnitude of the illusory effect as a function of the height of vertical strokes subdividing a spatial extension of fixed length, using the psychophysical standard-variable matching paradigm. For vertical strokes shorter than, or of the same height as strokes delimiting the standard, the length was over-reproduced consistently with earlier studies of the illusion. However, for vertical strokes three times longer than the delimiters, the illusory effect paradoxically decreased, and attained negative values in two of six subjects. The magnitude of the effect thus depends on the patterning of the space between the delimiters, not merely on the number of subdividing elements.

  6. A Streamline-Upwind Model for Filling Front Advection in Powder Injection Moulding

    NASA Astrophysics Data System (ADS)

    Larsen, Guillaume; Cheng, Zhi Qiang; Barriere, Thierry; Liu, Bao Sheng; Gelin, Jean-Claude

    2010-06-01

    The filling process of powder injection molding is modeled by the flows of two variably adjacent domains in the mold cavity. The feedstock is filled into the cavity while the air is expelled out by the injected feedstock [1]. Eulerian description is adopted. The filling patterns are determined by the solution of an advection equation, governed by the velocity field in both the feedstock flow and air flow [2]. In the real physics, the advance of filling front depends mainly on the flow of feedstock that locates behind the front. The flow of air in front of the injected material plays in fact no meaningful effect. However, the actual algorithm for solution of the advection equation takes equally the importance for both the flow of viscous feedstock and that of the slight air. Under such a condition, the injection flow of feedstock in simulation may be misdirected unrealistically by the velocity field in the air portion of the mold cavity. To correct this defect, an upwind scheme is proposed to reinforce the effect of upwind flow and reduce the effect of downstream flow. The present paper involves the investigation of an upwind algorithm for simulation of the filling state during powder injection molding. A Petrov-Galerkin upwind based method (SUPG) is adopted for numerical simulation of the transport equation instead of the Taylor-Galerkin method in previous work. In the proposed implementation of the Streamline-Upwind/Petrov-Galerkin (SUPG) approach. A stabilization method is used to prevent oscillations in the convection-dominated problems. It consists in the introduction of an artificial diffusion in streamline direction. Suitable modification of the test function is the important issue. It ensures the stable simulation of filling process and results in the more realistic prediction of filling patterns. The implementation of upwind scheme in mould filling state simulation, based on an advection equation and the whole velocity field of feedstock and air flow, makes

  7. A symplectic coherent beam-beam model

    SciTech Connect

    Furman, M.A.

    1989-05-01

    We consider a simple one-dimensional model to study the effects of the beam-beam force on the coherent dynamics of colliding beams. The key ingredient is a linearized beam-beam kick. We study only the quadrupole modes, with the dynamical variables being the 2nd-order moments of the canonical variables q, p. Our model is self-consistent in the sense that no higher order moments are generated by the linearized beam-beam kicks, and that the only source of violation of symplecticity is the radiation. We discuss the round beam case only, in which vertical and horizontal quantities are assumed to be equal (though they may be different in the two beams). Depending on the values of the tune and beam intensity, we observe steady states in which otherwise identical bunches have sizes that are equal, or unequal, or periodic, or behave chaotically from turn to turn. Possible implications of luminosity saturation with increasing beam intensity are discussed. Finally, we present some preliminary applications to an asymmetric collider. 8 refs., 8 figs.

  8. Complex Filling Dynamics in Mesoporous Thin Films.

    PubMed

    Mercuri, Magalí; Pierpauli, Karina; Bellino, Martín G; Berli, Claudio L A

    2017-01-10

    The fluid-front dynamics resulting from the coexisting infiltration and evaporation phenomena in nanofluidic systems has been investigated. More precisely, water infiltration in both titania and silica mesoporous films was studied through a simple experiment: a sessile drop was deposited over the film and the advancement of the fluid front into the porous structure was optically followed and recorded in time. In the case of titania mesoporous films, capillary infiltration was arrested at a given distance, and a steady annular region of the wetted material was formed. A simple model that combines Lucas-Washburn infiltration and surface evaporation was derived, which appropriately describes the observed filling dynamics and the annulus width in dissimilar mesoporous morphologies. In the case of wormlike mesoporous morphologies, a remarkable phenomenon was found: instead of reaching a steady infiltration-evaporation balance, the fluid front exhibits an oscillating behavior. This complex filling dynamics opens interesting possibilities to study the unusual nanofluidic phenomena and to discover novel applications.

  9. Rubber elasticity: From topology to filled elastomers

    SciTech Connect

    Heinrich, G.; Vilgis, T.A.

    1993-12-31

    Various new aspects in the elasticity of rubbers and statistics of unfilled and filled elastomers, together with various consequences for practical application are discussed. It is shown that the role of network topology is crucial in the statistics of rubbers. This is seen mostly on the influence of heterogeneities of crosslink density which determine the elastic modulus, ultimate properties as well as the dynamical behavior. The filler effects, entanglements in filled rubbers, and the filler/bound rubber/mobile rubber problem are discussed from a novel point of view. A localization model is adopted, where it can be shown that on a rough (filler) surface more polymer can be adsorbed compared to a flat surface with similar energetic properties. The role of carbon black networking and fractal properties of the filler are discussed in relation to the dynamic-mechanical properties of the elastomer.

  10. Liquid-filled Canyons on Titan

    NASA Astrophysics Data System (ADS)

    Poggiali, Valerio; Mastrogiuseppe, Marco; Hayes, Alexander; Seu, Roberto; Birch, Samuel; Lorenz, Ralph; Grima, Cyril; Kargel, Jeffrey; Hofgartner, Jason

    2016-04-01

    During a close flyby, Cassini's RADAR altimeter observed a system of channels pertaining to the Vid Flumina system that drain into Titan's Ligeia Mare. While SAR images have been used to identify fluvial valleys in networks that extend for hundreds of kilometers, they can't directly prove the presence and/or physical extent of liquid channels filling them. Analysis of altimeter echoes shows that the channels are located in deep (~500 m) canyons and have strongly specular surface reflections that indicate they are currently liquid-filled. Liquid elevations in Vid Flumina and its lower tributaries are at the same level of Ligeia Mare to within the altimeter's vertical accuracy of ~15m, which is a function of both the RADAR instrument as well as the precision of Cassini's reconstructed ephemeris. Specular reflections are also observed in higher order tributaries that occur hundred meters above the level of Ligeia Mare, consistent with drainage feeding into the main channel system.

  11. Antibacterial properties of temporary filling materials.

    PubMed

    Slutzky, Hagay; Slutzky-Goldberg, I; Weiss, E I; Matalon, S

    2006-03-01

    The purpose of this study was to investigate the antibacterial properties of temporary fillings. The direct contact test (DCT) was used to evaluate the antibacterial properties of Revoltek LC, Tempit, Systemp inlay, and IRM. These were tested in contact with Streptococcus mutans and Enterococcus faecalis. The materials were examined immediately after setting, 1, 7, 14, and 30 days after aging in phosphate buffered saline (PBS). Statistical analysis included two-way ANOVA, one-way ANOVA, and Tukey multiple comparison. Systemp inlay, Tempit, and IRM exhibited antibacterial properties when in contact with S. mutans for at least 7 days, Tempit and IRM sustained this ability for at least 14 days. When in contact with E. faecalis Tempit and IRM were antibacterial immediately after setting, IRM sustained this ability for at least 1 day. Our study suggests that the difference in temporary filling materials may influence which microorganism will be able to invade the root canal system.

  12. Useful technique for analysis and control of the acceleration beam phase in the azimuthally varying field cyclotron

    NASA Astrophysics Data System (ADS)

    Kurashima, Satoshi; Yuyama, Takahiro; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Okumura, Susumu; Fukuda, Mitsuhiro

    2010-03-01

    We have developed a new technique for analysis and control of the acceleration beam phase in the cyclotron. In this technique, the beam current pattern at a fixed radius r is measured by slightly scanning the acceleration frequency in the cyclotron. The acceleration beam phase is obtained by analyzing symmetry of the current pattern. Simple procedure to control the acceleration beam phase by changing coil currents of a few trim coils was established. The beam phase width is also obtained by analyzing gradient of the decreasing part of the current pattern. We verified reliability of this technique with 260 MeV N20e7+ beams which were accelerated on different tuning condition of the cyclotron. When the acceleration beam phase was around 0°, top of the energy gain of cosine wave, and the beam phase width was about 6° in full width at half maximum, a clear turn pattern of the beam was observed with a differential beam probe in the extraction region. Beam phase widths of ion beams at acceleration harmonics of h =1 and h =2 were estimated without beam cutting by phase-defining slits. We also calculated the beam phase widths roughly from the beam current ratio between the injected beam and the accelerated beam in the cyclotron without operating the beam buncher. Both beam phase widths were almost the same for h =1, while phase compressions by a factor of about 3 were confirmed for h =2.

  13. Useful technique for analysis and control of the acceleration beam phase in the azimuthally varying field cyclotron

    SciTech Connect

    Kurashima, Satoshi; Yuyama, Takahiro; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Okumura, Susumu; Fukuda, Mitsuhiro

    2010-03-15

    We have developed a new technique for analysis and control of the acceleration beam phase in the cyclotron. In this technique, the beam current pattern at a fixed radius r is measured by slightly scanning the acceleration frequency in the cyclotron. The acceleration beam phase is obtained by analyzing symmetry of the current pattern. Simple procedure to control the acceleration beam phase by changing coil currents of a few trim coils was established. The beam phase width is also obtained by analyzing gradient of the decreasing part of the current pattern. We verified reliability of this technique with 260 MeV {sup 20}Ne{sup 7+} beams which were accelerated on different tuning condition of the cyclotron. When the acceleration beam phase was around 0 deg., top of the energy gain of cosine wave, and the beam phase width was about 6 deg. in full width at half maximum, a clear turn pattern of the beam was observed with a differential beam probe in the extraction region. Beam phase widths of ion beams at acceleration harmonics of h=1 and h=2 were estimated without beam cutting by phase-defining slits. We also calculated the beam phase widths roughly from the beam current ratio between the injected beam and the accelerated beam in the cyclotron without operating the beam buncher. Both beam phase widths were almost the same for h=1, while phase compressions by a factor of about 3 were confirmed for h=2.

  14. Slotted Polyimide-Aerogel-Filled-Waveguide Arrays

    NASA Technical Reports Server (NTRS)

    Rodriguez-Solis, Rafael A.; Pacheco, Hector L.; Miranda, Felix A.; Meador, Mary Ann B.

    2013-01-01

    This presentation discussed the potential advantages of developing Slotted Waveguide Arrays using polyimide aerogels. Polyimide (PI) aerogels offer great promise as an enabling technology for lightweight aerospace antenna systems. PI aerogels are highly porous solids possessing low density and low dielectric permittivity combined with good mechanical properties. For slotted waveguide array applications, there are significant advantages in mass that more than compensate for the slightly higher loss of the aerogel filled waveguide when compared to state of practice commercial waveguide.

  15. Microscopic justification of the equal filling approximation

    SciTech Connect

    Perez-Martin, Sara; Robledo, L. M.

    2008-07-15

    The equal filling approximation, a procedure widely used in mean-field calculations to treat the dynamics of odd nuclei in a time-reversal invariant way, is justified as the consequence of a variational principle over an average energy functional. The ideas of statistical quantum mechanics are employed in the justification. As an illustration of the method, the ground and lowest-lying states of some octupole deformed radium isotopes are computed.

  16. Orofacial granulomatosis related to amalgam fillings.

    PubMed

    Ellison, R; Green, C; Gibson, J; Ghaffar, S

    2013-11-01

    This paper reports on a case of Orofacial Granulomatosis (OFG) in which the presence of amalgam fillings appears to have played a part in the aetiology. Once these restorations were removed and replaced with an alternative composite restorative material, all symptoms and signs of OFG resolved completely. This case highlights the necessity to include dental metals in the patch test battery when performing delayed patch testing on patients with OFG.

  17. Abandoned Channel Fill Sequences in Tidal Estuaries

    NASA Astrophysics Data System (ADS)

    Gray, A. B.; Pasternack, G. B.; Goni, M. A.; Watson, E. B.

    2014-12-01

    This study proposes a modification of the current model for abandoned channel fill stratigraphy produced in unidirectional flow river reaches to incorporate seasonal tidal deposition. Evidence supporting this concept came from a study of two consecutive channel abandonment sequences in Ropers Slough of the lower Eel River Estuary in northern California. Aerial photographs showed that Ropers Slough was abandoned around 1943, reoccupied after the 1964 flood, and abandoned again in 1974 with fill continuing to the present. Planform geomorphic characteristics derived from these images were used in conjunction with sub-cm resolution stratigraphic analyses to describe the depositional environment processes and their resultant sedimentary deposits. Results showed that both abandonment sequences recorded quasi-annual scale fluvial/tidal deposition couplets. In both cases tidal deposits contained very little sand, and were higher in organic and inorganic carbon content than the sandier fluvial through-flow deposits. However, the two abandonment fills differed significantly in terms of the temporal progression of channel narrowing and fluvial sediment deposition characteristics. The first abandonment sequence led to a more rapid narrowing of Ropers Slough and produced deposits with a positive relationship between grain size/deposit thickness and discharge. The second abandonment resulted in a much slower narrowing of Ropers Slough and generally thinner fluvial deposits with no clear relationship between grain size/deposit thickness and discharge. The δ13C values and organic nitrogen to organic carbon ratios of deposits from the first phase overlapped with Eel River suspended sediment characteristics found for low flows (1-5 times mean discharge), while those of the second phase were consistent suspended sediment from higher flows (7-10 times mean discharge). The abandoned channel fill sequences appeared to differ due to the topographic steering of bed sediment transport and

  18. COMSOL MULTIPHYSICS MODEL FOR DWPF CANISTER FILLING

    SciTech Connect

    Kesterson, M.

    2011-03-31

    The purpose of this work was to develop a model that can be used to predict temperatures of the glass in the Defense Waste Processing Facility (DWPF) canisters during filling and cooldown. Past attempts to model these processes resulted in large (>200K) differences in predicted temperatures compared to experimentally measured temperatures. This work was therefore intended to also generate a model capable of reproducing the experimentally measured trends of the glass/canister temperature during filling and subsequent cooldown of DWPF canisters. To accomplish this, a simplified model was created using the finite element modeling software COMSOL Multiphysics which accepts user defined constants or expressions to describe material properties. The model results were compared to existing experimental data for validation. A COMSOL Multiphysics model was developed to predict temperatures of the glass within DWPF canisters during filling and cooldown. The model simulations and experimental data were in good agreement. The largest temperature deviations were {approx}40 C for the 87inch thermocouple location at 3000 minutes and during the initial cooldown at the 51 inch location occurring at approximately 600 minutes. Additionally, the model described in this report predicts the general trends in temperatures during filling and cooling observed experimentally. However, the model was developed using parameters designed to fit a single set of experimental data. Therefore, Q-loss is not currently a function of pour rate and pour temperature. Future work utilizing the existing model should include modifying the Q-loss term to be variable based on flow rate and pour temperature. Further enhancements could include eliminating the Q-loss term for a user defined convection where Navier-Stokes does not need to be solved in order to have convection heat transfer.

  19. Moon - 'Ghost' craters formed during Mare filling.

    NASA Technical Reports Server (NTRS)

    Cruikshank, D. P.; Hartmann, W. K.; Wood, C. A.

    1973-01-01

    This paper discusses formation of 'pathological' cases of crater morphology due to interaction of craters with molten lavas. Terrestrial observations of such a process are discussed. In lunar maria, a number of small impact craters (D less than 10 km) may have been covered by thin layers of fluid lavas, or formed in molten lava. Some specific lunar examples are discussed, including unusual shallow rings resembling experimental craters deformed by isostatic filling.

  20. Statistical evaluation of metal fill widths for emulated metal fill in parasitic extraction methodology

    NASA Astrophysics Data System (ADS)

    J-Me, Teh; Noh, Norlaili Mohd.; Aziz, Zalina Abdul

    2015-05-01

    In the chip industry today, the key goal of a chip development organization is to develop and market chips within a short time frame to gain foothold on market share. This paper proposes a design flow around the area of parasitic extraction to improve the design cycle time. The proposed design flow utilizes the usage of metal fill emulation as opposed to the current flow which performs metal fill insertion directly. By replacing metal fill structures with an emulation methodology in earlier iterations of the design flow, this is targeted to help reduce runtime in fill insertion stage. Statistical design of experiments methodology utilizing the randomized complete block design was used to select an appropriate emulated metal fill width to improve emulation accuracy. The experiment was conducted on test cases of different sizes, ranging from 1000 gates to 21000 gates. The metal width was varied from 1 x minimum metal width to 6 x minimum metal width. Two-way analysis of variance and Fisher's least significant difference test were used to analyze the interconnect net capacitance values of the different test cases. This paper presents the results of the statistical analysis for the 45 nm process technology. The recommended emulated metal fill width was found to be 4 x the minimum metal width.