Advanced Mirror Technology Development

NASA Technical Reports Server (NTRS)

Stahl, H. Philip

2017-01-01

The Advanced Mirror Technology Development (AMTD) project matures critical technologies required to enable ultra-stable 4-m-or-larger monolithic or segmented ultraviolet, optical, and infrared (UVOIR) space telescope primary-mirror assemblies for general astrophysics and ultra-high-contrast observations of exoplanets.

Low-noise low-jitter 32-pixels CMOS single-photon avalanche diodes array for single-photon counting from 300 nm to 900 nm

DOE Office of Scientific and Technical Information (OSTI.GOV)

Scarcella, Carmelo; Tosi, Alberto, E-mail: alberto.tosi@polimi.it; Villa, Federica

2013-12-15

We developed a single-photon counting multichannel detection system, based on a monolithic linear array of 32 CMOS SPADs (Complementary Metal-Oxide-Semiconductor Single-Photon Avalanche Diodes). All channels achieve a timing resolution of 100 ps (full-width at half maximum) and a photon detection efficiency of 50% at 400 nm. Dark count rate is very low even at room temperature, being about 125 counts/s for 50 μm active area diameter SPADs. Detection performance and microelectronic compactness of this CMOS SPAD array make it the best candidate for ultra-compact time-resolved spectrometers with single-photon sensitivity from 300 nm to 900 nm.

31. SPILLWAY CHANNEL WALLS REINF DETAILS; MONOLITHS E21 AND ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

31. SPILLWAY CHANNEL WALLS REINF - DETAILS; MONOLITHS E-21 AND W-21. Sheet S-45, May, 1940. File no. 342/58. - Prado Dam, Spillway, Santa Ana River near junction of State Highways 71 & 91, Corona, Riverside County, CA

Creating Extended and Dense Plasma Channels in Air by Using Spatially and Temporally Shaped Ultra-Intense Laser Pulses

DTIC Science & Technology

2011-08-16

Wolf, Phys. Rev. Lett. 104, 103903 (2010). 6. M. Aközbek, M. Scalora , C. Bowden, and S. L. Chin, Opt. Commun. 191, 353 (2001). 7. A. Couairon, Phys...Aközbek, M. Scalora , C. Bowden, and S. L. Chin, “White-light continuum generation and filamentation during the propagation of ultra-short laser pulses in

26. SPILLWAY CHANNEL WALLS REINF. DETAILS; MONOLITHS W1 TO ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

26. SPILLWAY CHANNEL WALLS - REINF. DETAILS; MONOLITHS W-1 TO W-4 INCL. Sheet S-26, July, 1939. File no. SA 342/34. - Prado Dam, Spillway, Santa Ana River near junction of State Highways 71 & 91, Corona, Riverside County, CA

All-fiber high-power monolithic femtosecond laser at 1.59 µm with 63-fs pulse width

NASA Astrophysics Data System (ADS)

Hekmat, M. J.; Omoomi, M.; Gholami, A.; Yazdabadi, A. Bagheri; Abdollahi, M.; Hamidnejad, E.; Ebrahimi, A.; Normohamadi, H.

2018-01-01

In this research, by adopting an alternative novel approach to ultra-short giant pulse generation which basically originated from difficulties with traditional employed methods, an optimized Er/Yb co-doped double-clad fiber amplifier is applied to boost output average power of single-mode output pulses to a high level of 2-W at 1.59-µm central wavelength. Output pulses of approximately 63-fs pulse width at 52-MHz repetition rate are obtained in an all-fiber monolithic laser configuration. The idea of employing parabolic pulse amplification for stretching output pulses together with high-power pulse amplification using Er/Yb co-doped active fibers for compressing and boosting output average power plays crucial role in obtaining desired results. The proposed configuration enjoys massive advantages over previously reported literature which make it well-suited for high-power precision applications such as medical surgery. Detailed dynamics of pulse stretching and compressing in active fibers with different GVD parameters are numerically and experimentally investigated.

Cavity-enhanced frequency doubling from 795nm to 397.5nm ultra-violet coherent radiation with PPKTP crystals in the low pump power regime.

PubMed

Wen, Xin; Han, Yashuai; Bai, Jiandong; He, Jun; Wang, Yanhua; Yang, Baodong; Wang, Junmin

2014-12-29

We demonstrate a simple, compact and cost-efficient diode laser pumped frequency doubling system at 795 nm in the low power regime. In two configurations, a bow-tie four-mirror ring enhancement cavity with a PPKTP crystal inside and a semi-monolithic PPKTP enhancement cavity, we obtain 397.5nm ultra-violet coherent radiation of 35mW and 47mW respectively with a mode-matched fundamental power of about 110mW, corresponding to a conversion efficiency of 32% and 41%. The low loss semi-monolithic cavity leads to the better results. The constructed ultra-violet coherent radiation has good power stability and beam quality, and the system has huge potential in quantum optics and cold atom physics.

24. SPILLWAY CHANNEL WALLS REINFORCEMENT DETAILS; MONOLITHS E1 TO ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

24. SPILLWAY CHANNEL WALLS - REINFORCEMENT DETAILS; MONOLITHS E-1 TO F-4 INCL. & NO. 34. Sheet S-11, June, 1939. File no. SA 342/24(?). - Prado Dam, Spillway, Santa Ana River near junction of State Highways 71 & 91, Corona, Riverside County, CA

32. SPILLWAY CHANNEL WALLS REINF. DETAILS; MONOLITHS E22, E23, W22, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

32. SPILLWAY CHANNEL WALLS REINF. DETAILS; MONOLITHS E-22, E-23, W-22, AND W-23. Sheet S-46, May, 1940. File no. 342/59. - Prado Dam, Spillway, Santa Ana River near junction of State Highways 71 & 91, Corona, Riverside County, CA

Electrochromatography on acrylate-based monolith in cyclic olefin copolymer microchip: an attractive technology.

PubMed

Ladner, Y; Cretier, G; Faure, K

2015-01-01

Electrochromatography (EC) on a porous monolithic stationary phase prepared within the channels of a microsystem is an attractive alternative for on-chip separation. It combines the separation mechanisms of electrophoresis and liquid chromatography. Moreover, the porous polymer monolithic materials have become popular as stationary phase due to the ease and rapidity of fabrication via free radical photopolymerization. Here, we describe a hexyl acrylate (HA)-based porous monolith which is simultaneously in situ synthesized and anchored to the inner walls of the channel of a cyclic olefin copolymer (COC) device in only 2 min. The baseline separation of a mixture of neurotransmitters including six amino acids and two catecholamines is realized.

Design considerations for a monolithic, GaAs, dual-mode, QPSK/QASK, high-throughput rate transceiver. M.S. Thesis

NASA Technical Reports Server (NTRS)

Kot, R. A.; Oliver, J. D.; Wilson, S. G.

1984-01-01

A monolithic, GaAs, dual mode, quadrature amplitude shift keying and quadrature phase shift keying transceiver with one and two billion bits per second data rate is being considered to achieve a low power, small and ultra high speed communication system for satellite as well as terrestrial purposes. Recent GaAs integrated circuit achievements are surveyed and their constituent device types are evaluated. Design considerations, on an elemental level, of the entire modem are further included for monolithic realization with practical fabrication techniques. Numerous device types, with practical monolithic compatability, are used in the design of functional blocks with sufficient performances for realization of the transceiver.

Enhanced hole boring with two-color relativistic laser pulses in the fast ignition scheme

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Changhai; Tian, Ye; Li, Wentao

A scheme of using two-color laser pulses for hole boring into overdense plasma as well as energy transfer into electron and ion beams has been studied using particle-in-cell simulations. Following an ultra-short ultra-intense hole-boring laser pulse with a short central wavelength in extreme ultra-violet range, the main infrared driving laser pulse can be guided in the hollow channel preformed by the former laser and propagate much deeper into an overdense plasma, as compared to the case using the infrared laser only. In addition to efficiently transferring the main driving laser energy into energetic electrons and ions generation deep inside themore » overdense plasma, the ion beam divergence can be greatly reduced. The results might be beneficial for the fast ignition concept of inertial confinement fusion.« less

Ultra-low noise combs in the palm of your hand

NASA Astrophysics Data System (ADS)

Schibli, Thomas R.

Mode-locked lasers are attractive tools for precision measurements and for photonic microwave generation. The technology around these lasers has rapidly evolved, and with the invention of optical frequency combs, fs-technology has become a ubiquitous tool science and engineering. At first, most of these combs were generated by bulky and delicate Kerr-Lens mode-locked Ti:sapphire systems, but have now been mostly replaced by the much more robust and compact fiber lasers. However, the move from table-top solid-state lasers to the fully self-contained fiber systems came with a price: the optical phase noise performance degraded due to design constraints. While this is of no concern for most spectroscopic applications, it poses a challenge for applications that require excellent short-term phase noise performance, such as, for example, required for photonic microwave generation. While much of this has been improved by ingenious laser designs, it remains a challenge to obtain ultra-low phase-noise combs from high-repetition-rate fiber lasers. Here we present a new approach consisting of a monolithic cavity design, in which the laser light is fully confined inside an optical material. Thanks to this monolithic design, these solid-state lasers are inherently robust against environmental perturbations, such as acoustics, vibrations, air pressure and humidity. Opposed to the omnipresent mode-locked fiber lasers, these monolithic lasers exhibit very low round-trip loss, dispersion and nonlinearities. As a result, they produce highly stable pulse trains, with free-running relative line-widths of the order of a few Hz in the optical domain, despite their moderately high fundamental repetition rates of 1 GHz. The compact design further simplifies integration into complex systems, and eliminates the need for an optics bench or a vibration isolated platform. These lasers produce less than 0.2 W of heat, and are fully turn-key. This work was supported by the DARPA PULSE program with a Grant from AMRDEC and by the NSF Early Career Award.

Short-channel field-effect transistors with 9-atom and 13-atom wide graphene nanoribbons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Llinas, Juan Pablo; Fairbrother, Andrew; Borin Barin, Gabriela

Bottom-up synthesized graphene nanoribbons and graphene nanoribbon heterostructures have promising electronic properties for high-performance field-effect transistors and ultra-low power devices such as tunneling field-effect transistors. However, the short length and wide band gap of these graphene nanoribbons have prevented the fabrication of devices with the desired performance and switching behavior. Here, by fabricating short channel (L ch ~ 20 nm) devices with a thin, high-κ gate dielectric and a 9-atom wide (0.95 nm) armchair graphene nanoribbon as the channel material, we demonstrate field-effect transistors with high on-current (I on > 1 μA at V d = -1 V) and highmore » I on /I off ~ 10 5 at room temperature. We find that the performance of these devices is limited by tunneling through the Schottky barrier at the contacts and we observe an increase in the transparency of the barrier by increasing the gate field near the contacts. Our results thus demonstrate successful fabrication of high-performance short-channel field-effect transistors with bottom-up synthesized armchair graphene nanoribbons.« less

Short-channel field-effect transistors with 9-atom and 13-atom wide graphene nanoribbons

DOE PAGES

Llinas, Juan Pablo; Fairbrother, Andrew; Borin Barin, Gabriela; ...

2017-09-21

Bottom-up synthesized graphene nanoribbons and graphene nanoribbon heterostructures have promising electronic properties for high-performance field-effect transistors and ultra-low power devices such as tunneling field-effect transistors. However, the short length and wide band gap of these graphene nanoribbons have prevented the fabrication of devices with the desired performance and switching behavior. Here, by fabricating short channel (L ch ~ 20 nm) devices with a thin, high-κ gate dielectric and a 9-atom wide (0.95 nm) armchair graphene nanoribbon as the channel material, we demonstrate field-effect transistors with high on-current (I on > 1 μA at V d = -1 V) and highmore » I on /I off ~ 10 5 at room temperature. We find that the performance of these devices is limited by tunneling through the Schottky barrier at the contacts and we observe an increase in the transparency of the barrier by increasing the gate field near the contacts. Our results thus demonstrate successful fabrication of high-performance short-channel field-effect transistors with bottom-up synthesized armchair graphene nanoribbons.« less

TDM interrogation of intensity-modulated USFBGs network based on multichannel lasers.

PubMed

Rohollahnejad, Jalal; Xia, Li; Cheng, Rui; Ran, Yanli; Rahubadde, Udaya; Zhou, Jiaao; Zhu, Lin

2017-01-23

We report a large-scale multi-channel fiber sensing network, where ultra-short FBGs (USFBGs) instead of conventional narrow-band ultra-weak FBGs are used as the sensors. In the time division multiplexing scheme of the network, each grating response is resolved as three adjacent discrete peaks. The central wavelengths of USFBGs are tracked with the differential detection, which is achieved by calculating the peak-to-peak ratio of two maximum peaks. Compared with previous large-scale hybrid multiplexing sensing networks (e.g., WDM/TDM) which typically have relatively low interrogation speed and very high complexity, the proposed system can achieve interrogation of all channel sensors through very fast and simple intensity measurements with a broad dynamic range. A proof-of-concept experiment with twenty USFBGs, at two wavelength channels, was performed and a fast static strain measurements were demonstrated, with a high average sensitivity of ~0.54dB/µƐ and wide dynamic range of over ~3000µƐ. The channel to channel switching time was 10ms and total network interrogation time was 50ms.

Doped-channel heterojunction structures for millimeter-wave discrete devices and MMICs

NASA Technical Reports Server (NTRS)

Saunier, P.; Kao, Y. C.; Khatibzadeh, A. M.; Tserng, H. Q.; Bradshaw, K.

1989-01-01

AlGaAs/InGaAs/GaAs-type heterostructures with one or two channels have been used to fabricate both discrete devices and monolithic amplifiers for millimeter-wave operation. The authors report that 0.25-micron x 50-micron discrete devices delivered a power density of 1 W/mm with 2.9-dB gain and 25 percent efficiency at 60 GHz. A 100-micron monolithic single-stage amplifier demonstrated a record 40 percent efficiency at 32 GHz, and a two-stage monolithic amplifier achieved a record 31.3 percent efficiency with 72-mW power and 13-dB gain at 32 GHz.

Recent progress in low-temperature-process monolithic three dimension technology

NASA Astrophysics Data System (ADS)

Yang, Chih-Chao; Hsieh, Tung-Ying; Huang, Wen-Hsien; Shen, Chang-Hong; Shieh, Jia-Min; Yeh, Wen-Kuan; Wu, Meng-Chyi

2018-04-01

Monolithic three-dimension (3D) integration is an ultimate alternative method of fabricating high density, high performance, and multi-functional integrated circuits. It offers the promise of being a new approach to increase system performance. How to manage the thermal impact of multi-tiered processes, such as dopant activation, source/drain silicidation, and channel formation, and to prevent the degradation of pre-existing devices/circuits become key challenges. In this paper, we provide updates on several important monolithic 3D works, particularly in sequentially stackable channels, and our recent achievements in monolithic 3D integrated circuit (3D-IC). These results indicate that the advanced 3D architecture with novel design tools enables ultrahigh-density stackable circuits to have superior performance and low power consumption for future artificial intelligence (AI) and internet of things (IoTs) application.

Monolithic integration of microfluidic channels and semiconductor lasers.

PubMed

Cran-McGreehin, Simon J; Dholakia, Kishan; Krauss, Thomas F

2006-08-21

We present a fabrication method for the monolithic integration of microfluidic channels into semiconductor laser material. Lasers are designed to couple directly into the microfluidic channel, allowing submerged particles pass through the output beams of the lasers. The interaction between particles in the channel and the lasers, operated in either forward or reverse bias, allows for particle detection, and the optical forces can be used to trap and move particles. Both interrogation and manipulation are made more amenable for lab-on-a-chip applications through monolithic integration. The devices are very small, they require no external optical components, have perfect intrinsic alignment, and can be created with virtually any planar configuration of lasers in order to perform a variety of tasks. Their operation requires no optical expertise and only low electrical power, thus making them suitable for computer interfacing and automation. Insulating the pn junctions from the fluid is the key challenge, which is overcome by using photo-definable SU8-2000 polymer.

Monolithic integration of microfluidic channels and semiconductor lasers

NASA Astrophysics Data System (ADS)

Cran-McGreehin, Simon J.; Dholakia, Kishan; Krauss, Thomas F.

2006-08-01

We present a fabrication method for the monolithic integration of microfluidic channels into semiconductor laser material. Lasers are designed to couple directly into the microfluidic channel, allowing submerged particles pass through the output beams of the lasers. The interaction between particles in the channel and the lasers, operated in either forward or reverse bias, allows for particle detection, and the optical forces can be used to trap and move particles. Both interrogation and manipulation are made more amenable for lab-on-a-chip applications through monolithic integration. The devices are very small, they require no external optical components, have perfect intrinsic alignment, and can be created with virtually any planar configuration of lasers in order to perform a variety of tasks. Their operation requires no optical expertise and only low electrical power, thus making them suitable for computer interfacing and automation. Insulating the pn junctions from the fluid is the key challenge, which is overcome by using photo-definable SU8-2000 polymer.

Experimental evidence of mobility enhancement in short-channel ultra-thin body double-gate MOSFETs by magnetoresistance technique

NASA Astrophysics Data System (ADS)

Chaisantikulwat, W.; Mouis, M.; Ghibaudo, G.; Cristoloveanu, S.; Widiez, J.; Vinet, M.; Deleonibus, S.

2007-11-01

Double-gate transistor with ultra-thin body (UTB) has proved to offer advantages over bulk device for high-speed, low-power applications. There is thus a strong need to obtain an accurate understanding of carrier transport and mobility in such device. In this work, we report for the first time an experimental evidence of mobility enhancement in UTB double-gate (DG) MOSFETs using magnetoresistance mobility extraction technique. Mobility in planar DG transistor operating in single- and double-gate mode is compared. The influence of different scattering mechanisms in the channel is also investigated by obtaining mobility values at low temperatures. The results show a clear mobility improvement in double-gate mode compared to single-gate mode mobility at the same inversion charge density. This is explained by the role of volume inversion in ultra-thin body transistor operating in DG mode. Volume inversion is found to be especially beneficial in terms of mobility gain at low-inversion densities.

Integrated ultra-low-loss resonator on a chip

NASA Astrophysics Data System (ADS)

Poon, Joyce K. S.

2018-05-01

Exquisitely low-loss optical resonators have thus far remained discrete. Monolithic integration of waveguides with silica resonators that have Q factors >100 million charts a path toward incorporating these devices in photonic circuits.

Method for the removal of ultrafine particulates from an aqueous suspension

DOEpatents

Chaiko, David J.; Kopasz, John P.; Ellison, Adam J. G.

2000-01-01

A method of separating ultra-fine particulates from an aqueous suspension such as a process stream or a waste stream. The method involves the addition of alkali silicate and an organic gelling agent to a volume of liquid, from the respective process or waste stream, to form a gel. The gel then undergoes syneresis to remove water and soluble salts from the gel containing the particulates, thus, forming a silica monolith. The silica monolith is then sintered to form a hard, nonporous waste form.

Method for the Removal of Ultrafine Particulates from an Aqueous Suspension

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chaiko, David J.; Kopasz, John P.; Ellison, Adam J.G.

1999-03-05

A method of separating ultra-fine particulate from an aqueous suspension such as a process stream or a waste stream. The method involves the addition of alkali silicate and an organic gelling agent to a volume of liquid, from the respective process or waste stream, to form a gel. The gel then undergoes syneresis to remove water and soluble salts from the gel-containing the particulate, thus, forming a silica monolith. The silica monolith is then sintered to form a hard, nonporous waste form.

Giant electron-hole transport asymmetry in ultra-short quantum transistors.

PubMed

McRae, A C; Tayari, V; Porter, J M; Champagne, A R

2017-05-31

Making use of bipolar transport in single-wall carbon nanotube quantum transistors would permit a single device to operate as both a quantum dot and a ballistic conductor or as two quantum dots with different charging energies. Here we report ultra-clean 10 to 100 nm scale suspended nanotube transistors with a large electron-hole transport asymmetry. The devices consist of naked nanotube channels contacted with sections of tube under annealed gold. The annealed gold acts as an n-doping top gate, allowing coherent quantum transport, and can create nanometre-sharp barriers. These tunnel barriers define a single quantum dot whose charging energies to add an electron or a hole are vastly different (e-h charging energy asymmetry). We parameterize the e-h transport asymmetry by the ratio of the hole and electron charging energies η e-h . This asymmetry is maximized for short channels and small band gap tubes. In a small band gap device, we demonstrate the fabrication of a dual functionality quantum device acting as a quantum dot for holes and a much longer quantum bus for electrons. In a 14 nm-long channel, η e-h reaches up to 2.6 for a device with a band gap of 270 meV. The charging energies in this device exceed 100 meV.

Monolithically compatible impedance measurement

DOEpatents

Ericson, Milton Nance; Holcomb, David Eugene

2002-01-01

A monolithic sensor includes a reference channel and at least one sensing channel. Each sensing channel has an oscillator and a counter driven by the oscillator. The reference channel and the at least one sensing channel being formed integrally with a substrate and intimately nested with one another on the substrate. Thus, the oscillator and the counter have matched component values and temperature coefficients. A frequency determining component of the sensing oscillator is formed integrally with the substrate and has an impedance parameter which varies with an environmental parameter to be measured by the sensor. A gating control is responsive to an output signal generated by the reference channel, for terminating counting in the at least one sensing channel at an output count, whereby the output count is indicative of the environmental parameter, and successive ones of the output counts are indicative of changes in the environmental parameter.

Short-channel field-effect transistors with 9-atom and 13-atom wide graphene nanoribbons.

PubMed

Llinas, Juan Pablo; Fairbrother, Andrew; Borin Barin, Gabriela; Shi, Wu; Lee, Kyunghoon; Wu, Shuang; Yong Choi, Byung; Braganza, Rohit; Lear, Jordan; Kau, Nicholas; Choi, Wonwoo; Chen, Chen; Pedramrazi, Zahra; Dumslaff, Tim; Narita, Akimitsu; Feng, Xinliang; Müllen, Klaus; Fischer, Felix; Zettl, Alex; Ruffieux, Pascal; Yablonovitch, Eli; Crommie, Michael; Fasel, Roman; Bokor, Jeffrey

2017-09-21

Bottom-up synthesized graphene nanoribbons and graphene nanoribbon heterostructures have promising electronic properties for high-performance field-effect transistors and ultra-low power devices such as tunneling field-effect transistors. However, the short length and wide band gap of these graphene nanoribbons have prevented the fabrication of devices with the desired performance and switching behavior. Here, by fabricating short channel (L ch  ~ 20 nm) devices with a thin, high-κ gate dielectric and a 9-atom wide (0.95 nm) armchair graphene nanoribbon as the channel material, we demonstrate field-effect transistors with high on-current (I on  > 1 μA at V d  = -1 V) and high I on /I off  ~ 10 5 at room temperature. We find that the performance of these devices is limited by tunneling through the Schottky barrier at the contacts and we observe an increase in the transparency of the barrier by increasing the gate field near the contacts. Our results thus demonstrate successful fabrication of high-performance short-channel field-effect transistors with bottom-up synthesized armchair graphene nanoribbons.Graphene nanoribbons show promise for high-performance field-effect transistors, however they often suffer from short lengths and wide band gaps. Here, the authors use a bottom-up synthesis approach to fabricate 9- and 13-atom wide ribbons, enabling short-channel transistors with 10 5 on-off current ratio.

Advanced technologies demonstrated by the miniature integrated camera and spectrometer (MICAS) aboard deep space 1

USGS Publications Warehouse

Rodgers, D.H.; Beauchamp, P.M.; Soderblom, L.A.; Brown, R.H.; Chen, G.-S.; Lee, M.; Sandel, B.R.; Thomas, D.A.; Benoit, R.T.; Yelle, R.V.

2007-01-01

MICAS is an integrated multi-channel instrument that includes an ultraviolet imaging spectrometer (80-185 nm), two high-resolution visible imagers (10-20 ??rad/pixel, 400-900 nm), and a short-wavelength infrared imaging spectrometer (1250-2600 nm). The wavelength ranges were chosen to maximize the science data that could be collected using existing semiconductor technologies and avoiding the need for multi-octave spectrometers. It was flown on DS1 to validate technologies derived from the development of PICS (Planetary Imaging Camera Spectrometer). These technologies provided a novel systems approach enabling the miniaturization and integration of four instruments into one entity, spanning a wavelength range from the UV to IR, and from ambient to cryogenic temperatures with optical performance at a fraction of a wavelength. The specific technologies incorporated were: a built-in fly-by sequence; lightweight and ultra-stable, monolithic silicon-carbide construction, which enabled room-temperature alignment for cryogenic (85-140 K) performance, and provided superb optical performance and immunity to thermal distortion; diffraction-limited, shared optics operating from 80 to 2600 nm; advanced detector technologies for the UV, visible and short-wavelength IR; high-performance thermal radiators coupled directly to the short-wave infrared (SWIR) detector optical bench, providing an instrument with a mass less than 10 kg, instrument power less than 10 W, and total instrument cost of less than ten million dollars. The design allows the wavelength range to be extended by at least an octave at the short wavelength end and to 50 microns at the long wavelength end. Testing of the completed instrument demonstrated excellent optical performance down to 77 K, which would enable a greatly reduced background for longer wavelength detectors. During the Deep Space 1 Mission, MICAS successfully collected images and spectra for asteroid 9969 Braille, Mars, and comet 19/P Borrelly. The Borrelly encounter was a scientific hallmark providing the first clear, high resolution images and excellent, short-wavelength infrared spectra of the surface of an active comet's nucleus. ?? 2007 Springer Science+Business Media, Inc.

Magnetohydrodynamic generator electrode

DOEpatents

Marchant, David D.; Killpatrick, Don H.; Herman, Harold; Kuczen, Kenneth D.

1979-01-01

An improved electrode for use as a current collector in the channel of a magnetohydrodynamid (MHD) generator utilizes an elongated monolithic cap of dense refractory material compliantly mounted to the MHD channel frame for collecting the current. The cap has a central longitudinal channel which contains a first layer of porous refractory ceramic as a high-temperature current leadout from the cap and a second layer of resilient wire mesh in contact with the first layer as a low-temperature current leadout between the first layer and the frame. Also described is a monolithic ceramic insulator compliantly mounted to the frame parallel to the electrode by a plurality of flexible metal strips.

Monolithic solid-state lasers for spaceflight

NASA Astrophysics Data System (ADS)

Krainak, Michael A.; Yu, Anthony W.; Stephen, Mark A.; Merritt, Scott; Glebov, Leonid; Glebova, Larissa; Ryasnyanskiy, Aleksandr; Smirnov, Vadim; Mu, Xiaodong; Meissner, Stephanie; Meissner, Helmuth

2015-02-01

A new solution for building high power, solid state lasers for space flight is to fabricate the whole laser resonator in a single (monolithic) structure or alternatively to build a contiguous diffusion bonded or welded structure. Monolithic lasers provide numerous advantages for space flight solid-state lasers by minimizing misalignment concerns. The closed cavity is immune to contamination. The number of components is minimized thus increasing reliability. Bragg mirrors serve as the high reflector and output coupler thus minimizing optical coatings and coating damage. The Bragg mirrors also provide spectral and spatial mode selection for high fidelity. The monolithic structure allows short cavities resulting in short pulses. Passive saturable absorber Q-switches provide a soft aperture for spatial mode filtering and improved pointing stability. We will review our recent commercial and in-house developments toward fully monolithic solid-state lasers.

Optimization of monolithic columns for microfluidic devices

NASA Astrophysics Data System (ADS)

Pagaduan, Jayson V.; Yang, Weichun; Woolley, Adam T.

2011-06-01

Monolithic columns offer advantages as solid-phase extractors because they offer high surface area that can be tailored to a specific function, fast mass transport, and ease of fabrication. Porous glycidyl methacrylate-ethylene glycol dimethacrylate monoliths were polymerized in-situ in microfluidic devices, without pre-treatment of the poly(methyl methacrylate) channel surface. Cyclohexanol, 1-dodecanol and Tween 20 were used to control the pore size of the monoliths. The epoxy groups on the monolith surface can be utilized to immobilize target-specific probes such as antibodies, aptamers, or DNA for biomarker detection. Microfluidic devices integrated with solid-phase extractors should be useful for point-of-care diagnostics in detecting specific biomarkers from complex biological fluids.

Microchemical Systems and Their Applications Workshop Held on 16-18 June 1999 in Reston, Virginia

DTIC Science & Technology

2000-03-29

USABLE BY- PRODUCT HYDROGEN, BUT COST OF THE PT COATED CERAMIC TUBES IS HIGH, HEAT TRANSFER EFFICIENCY IS LIMITED, AND THE RISK ASSOCIATED WITH...Monolith reactor Monolith Catalyst A Gas mixture i quartz tube T 1 Radiation Shields GC / analysis 3M Monolith Catalysts *-v.V...polyamide. MicroChannel patterned laminates are fabricated from polyamide while microfin -patterned laminates are fabricated from copper. In addition to

Robust ion current oscillations under a steady electric field: An ion channel analog.

PubMed

Yan, Yu; Wang, Yunshan; Senapati, Satyajyoti; Schiffbauer, Jarrod; Yossifon, Gilad; Chang, Hsueh-Chia

2016-08-01

We demonstrate a nonlinear, nonequilibrium field-driven ion flux phenomenon, which unlike Teorell's nonlinear multiple field theory, requires only the application of one field: robust autonomous current-mass flux oscillations across a porous monolith coupled to a capillary with a long air bubble, which mimics a hydrophobic protein in an ion channel. The oscillations are driven by the hysteretic wetting dynamics of the meniscus when electro-osmotic flow and pressure driven backflow, due to bubble expansion, compete to approach zero mass flux within the monolith. Delayed rupture of the film around the advancing bubble cuts off the electric field and switches the monolith mass flow from the former to the latter. The meniscus then recedes and repairs the rupture to sustain an oscillation for a range of applied fields. This generic mechanism shares many analogs with current oscillations in cell membrane ion channel. At sufficiently high voltage, the system undergoes a state transition characterized by appearance of the ubiquitous 1/f power spectrum.

Measuring the Non-Line-of-Sight Ultra-High-Frequency Channel in Mountainous Terrain: A Spread-Spectrum, Portable Channel Sounder

DTIC Science & Technology

2018-03-01

ER D C/ CR RE L TR -1 8- 3 ERDC 6.1 Basic Research Measuring the Non-Line-of-Sight Ultra- High - Frequency Channel in Mountainous Terrain... High - Frequency Channel in Mountainous Terrain A Spread-Spectrum, Portable Channel Sounder Samuel S. Streeter and Daniel J. Breton U.S. Army...spread-spectrum, portable channel sounder specifically designed to meas- ure the non-line-of-sight, ultra- high -frequency channel in mountainous terrain

InP-based compact transversal filter for monolithically integrated light source array.

PubMed

Ueda, Yuta; Fujisawa, Takeshi; Takahata, Kiyoto; Kohtoku, Masaki; Ishii, Hiroyuki

2014-04-07

We developed an InP-based 4x1 transversal filter (TF) with multi-mode interference couplers (MMIs) as a compact wavelength multiplexer (MUX) 1700 μm x 400 μm in size. Furthermore, we converted the MMI-based TF to a reflection type to obtain an ultra-compact MUX of only 900 μm x 50 μm. These MUXs are made with a simple fabrication process and show a satisfactory wavelength filtering operation as MUXs of monolithically integrated light source arrays, for example, for 100G bit Ethernet.

Fabrication of a wide-field NIR integral field unit for SWIMS using ultra-precision cutting

NASA Astrophysics Data System (ADS)

Kitagawa, Yutaro; Yamagata, Yutaka; Morita, Shin-ya; Motohara, Kentaro; Ozaki, Shinobu; Takahashi, Hidenori; Konishi, Masahiro; Kato, Natsuko M.; Kobayakawa, Yutaka; Terao, Yasunori; Ohashi, Hirofumi

2016-07-01

We describe overview of fabrication methods and measurement results of test fabrications of optical surfaces for an integral field unit (IFU) for Simultaneous color Wide-field Infrared Multi-object Spectrograph, SWIMS, which is a first-generation instrument for the University of Tokyo Atacama Observatory 6.5-m telescope. SWIMS-IFU provides entire near-infrared spectrum from 0.9 to 2.5 μm simultaneously covering wider field of view of 17" × 13" compared with current near-infrared IFUs. We investigate an ultra-precision cutting technique to monolithically fabricate optical surfaces of IFU optics such as an image slicer. Using 4- or 5-axis ultra precision machine we compare the milling process and shaper cutting process to find the best way of fabrication of image slicers. The measurement results show that the surface roughness almost satisfies our requirement in both of two methods. Moreover, we also obtain ideal surface form in the shaper cutting process. This method will be adopted to other mirror arrays (i.e. pupil mirror and slit mirror, and such monolithic fabrications will also help us to considerably reduce alignment procedure of each optical elements.

Multiplexed electrokinetic sample fractionation, preconcentration and elution for proteomics.

PubMed

Hua, Yujuan; Jemere, Abebaw B; Dragoljic, Jelena; Harrison, D Jed

2013-07-07

Both 6 and 8-channel integrated microfluidic sample pretreatment devices capable of performing "in space" sample fractionation, collection, preconcentration and elution of captured analytes via sheath flow assisted electrokinetic pumping are described. Coatings and monolithic polymer beds were developed for the glass devices to provide cationic surface charge and anodal electroosmotic flow for delivery to an electrospray emitter tip. A mixed cationic ([2-(methacryloyloxy)ethyl] trimethylammonium chloride) (META) and hydrophobic butyl methacrylate-based monolithic porous polymer, photopolymerized in the 6- or 8-fractionation channels, was used to capture and preconcentrate samples. A 0.45 wt% META loaded bed generated comparable anodic electroosmotic flow to the cationic polymer PolyE-323 coated channel segments in the device. The balanced electroosmotic flow allowed stable electrokinetic sheath flow to prevent cross contamination of separated protein fractions, while reducing protein/peptide adsorption on the channel walls. Sequential elution of analytes trapped in the SPE beds revealed that the monolithic columns could be efficiently used to provide sheath flow during elution of analytes, as demonstrated for neutral carboxy SNARF (residual signal, 0.08% RSD, n = 40) and charged fluorescein (residual signal, 2.5% n = 40). Elution from monolithic columns showed reproducible performance with peak area reproducibility of ~8% (n = 6 columns) in a single sequential elution and the run-to-run reproducibility was 2.4-6.7% RSD (n = 4) for elution from the same bed. The demonstrated ability of this device design and operation to elute from multiple fractionation beds into a single exit channel for sample analysis by fluorescence or electrospray mass spectrometry is a crucial component of an integrated fractionation and assay system for proteomics.

Giant electron-hole transport asymmetry in ultra-short quantum transistors

PubMed Central

McRae, A. C.; Tayari, V.; Porter, J. M.; Champagne, A. R.

2017-01-01

Making use of bipolar transport in single-wall carbon nanotube quantum transistors would permit a single device to operate as both a quantum dot and a ballistic conductor or as two quantum dots with different charging energies. Here we report ultra-clean 10 to 100 nm scale suspended nanotube transistors with a large electron-hole transport asymmetry. The devices consist of naked nanotube channels contacted with sections of tube under annealed gold. The annealed gold acts as an n-doping top gate, allowing coherent quantum transport, and can create nanometre-sharp barriers. These tunnel barriers define a single quantum dot whose charging energies to add an electron or a hole are vastly different (e−h charging energy asymmetry). We parameterize the e−h transport asymmetry by the ratio of the hole and electron charging energies ηe−h. This asymmetry is maximized for short channels and small band gap tubes. In a small band gap device, we demonstrate the fabrication of a dual functionality quantum device acting as a quantum dot for holes and a much longer quantum bus for electrons. In a 14 nm-long channel, ηe−h reaches up to 2.6 for a device with a band gap of 270 meV. The charging energies in this device exceed 100 meV. PMID:28561024

Monolithically interconnected GaAs solar cells: A new interconnection technology for high voltage solar cell output

NASA Astrophysics Data System (ADS)

Dinetta, L. C.; Hannon, M. H.

1995-10-01

Photovoltaic linear concentrator arrays can benefit from high performance solar cell technologies being developed at AstroPower. Specifically, these are the integration of thin GaAs solar cell and epitaxial lateral overgrowth technologies with the application of monolithically interconnected solar cell (MISC) techniques. This MISC array has several advantages which make it ideal for space concentrator systems. These are high system voltage, reliable low cost monolithically formed interconnections, design flexibility, costs that are independent of array voltage, and low power loss from shorts, opens, and impact damage. This concentrator solar cell will incorporate the benefits of light trapping by growing the device active layers over a low-cost, simple, PECVD deposited silicon/silicon dioxide Bragg reflector. The high voltage-low current output results in minimal 12R losses while properly designing the device allows for minimal shading and resistance losses. It is possible to obtain open circuit voltages as high as 67 volts/cm of solar cell length with existing technology. The projected power density for the high performance device is 5 kW/m for an AMO efficiency of 26% at 1 5X. Concentrator solar cell arrays are necessary to meet the power requirements of specific mission platforms and can supply high voltage power for electric propulsion systems. It is anticipated that the high efficiency, GaAs monolithically interconnected linear concentrator solar cell array will enjoy widespread application for space based solar power needs. Additional applications include remote man-portable or ultra-light unmanned air vehicle (UAV) power supplies where high power per area, high radiation hardness and a high bus voltage or low bus current are important. The monolithic approach has a number of inherent advantages, including reduced cost per interconnect and increased reliability of array connections. There is also a high potential for a large number of consumer products. Dual-use applications can include battery chargers and remote power supplies for consumer electronics products such as portable telephones/beepers, portable radios, CD players, dashboard radar detectors, remote walkway lighting, etc.

Monolithically interconnected GaAs solar cells: A new interconnection technology for high voltage solar cell output

NASA Technical Reports Server (NTRS)

Dinetta, L. C.; Hannon, M. H.

1995-01-01

Photovoltaic linear concentrator arrays can benefit from high performance solar cell technologies being developed at AstroPower. Specifically, these are the integration of thin GaAs solar cell and epitaxial lateral overgrowth technologies with the application of monolithically interconnected solar cell (MISC) techniques. This MISC array has several advantages which make it ideal for space concentrator systems. These are high system voltage, reliable low cost monolithically formed interconnections, design flexibility, costs that are independent of array voltage, and low power loss from shorts, opens, and impact damage. This concentrator solar cell will incorporate the benefits of light trapping by growing the device active layers over a low-cost, simple, PECVD deposited silicon/silicon dioxide Bragg reflector. The high voltage-low current output results in minimal 12R losses while properly designing the device allows for minimal shading and resistance losses. It is possible to obtain open circuit voltages as high as 67 volts/cm of solar cell length with existing technology. The projected power density for the high performance device is 5 kW/m for an AMO efficiency of 26% at 1 5X. Concentrator solar cell arrays are necessary to meet the power requirements of specific mission platforms and can supply high voltage power for electric propulsion systems. It is anticipated that the high efficiency, GaAs monolithically interconnected linear concentrator solar cell array will enjoy widespread application for space based solar power needs. Additional applications include remote man-portable or ultra-light unmanned air vehicle (UAV) power supplies where high power per area, high radiation hardness and a high bus voltage or low bus current are important. The monolithic approach has a number of inherent advantages, including reduced cost per interconnect and increased reliability of array connections. There is also a high potential for a large number of consumer products. Dual-use applications can include battery chargers and remote power supplies for consumer electronics products such as portable telephones/beepers, portable radios, CD players, dashboard radar detectors, remote walkway lighting, etc.

Less common applications of monoliths III. Gas chromatography

PubMed Central

Svec, Frantisek; Kurganov, Alexander A.

2008-01-01

Porous polymer monoliths emerged about two decades ago. Despite this short time, they are finding applications in a variety of fields. In addition to the most common and certainly best known use of this new category of porous media as stationary phases in liquid chromatography, monolithic materials also found their applications in other areas. This review article focuses on monoliths in capillaries designed for separations in gas chromatography. PMID:17645884

Monolithic integration of an InP-based 4 × 25 GHz photodiode array to an O-band arrayed waveguide grating demultiplexer

NASA Astrophysics Data System (ADS)

Ye, Han; Han, Qin; Lv, Qianqian; Pan, Pan; An, Junming; Yang, Xiaohong

2017-12-01

We demonstrate the monolithic integration of a uni-traveling carrier photodiode array with a 4 channel, O-band arrayed waveguide grating demultiplexer on the InP platform by the selective area growth technique. An extended coupling layer at the butt-joint is adopted to ensure both good fabrication compatibility and high photodiode quantum efficiency of 77%. The fabricated integrated chip exhibits a uniform bandwidth over 25 GHz for each channel and a crosstalk below -22 dB.

Monolithic single mode interband cascade lasers with wide wavelength tunability

NASA Astrophysics Data System (ADS)

von Edlinger, M.; Weih, R.; Scheuermann, J.; Nähle, L.; Fischer, M.; Koeth, J.; Kamp, M.; Höfling, S.

2016-11-01

Monolithic two-section interband cascade lasers offering a wide wavelength tunability in the wavelength range around 3.7 μm are presented. Stable single mode emission in several wavelength channels was realized using the concept of binary superimposed gratings and two-segment Vernier-tuning. The wavelength selective elements in the two segments were based on specially designed lateral metal grating structures defined by electron beam lithography. A dual-step dry etch process provided electrical separation between the segments. Individual current control of the segments allowed wavelength channel selection as well as continuous wavelength tuning within channels. A discontinuous tuning range extending over 158 nm in up to six discrete wavelength channels was achieved. Mode hop free wavelength tuning up to 14 nm was observed within one channel. The devices can be operated in continuous wave mode up to 30 °C with the output powers of 3.5 mW around room temperature.

Regenerable adsorption system

NASA Technical Reports Server (NTRS)

Roychoudhury, Subir (Inventor); Perry, Jay (Inventor); Walsh, Dennis (Inventor)

2006-01-01

A method for regenerable adsorption includes providing a substrate that defines at least one layer of ultra short channel length mesh capable of conducting an electrical current therethrough, coating at least a portion of the substrate with a desired sorbent for trace contaminant control or CO.sub.2 sorption, resistively heating the substrate, and passing a flowstream through the substrate and in contact with the sorbent.

Catalytic Ignition and Upstream Reaction Propagation in a Platinum Tube

NASA Technical Reports Server (NTRS)

Struk, P. M.; Dietrich, D. L.; Mellish, B. P.; Miller, F. J.; T'ien, J. S.

2007-01-01

A challenge for catalytic combustion in monolithic reactors at elevated temperatures is the start-up or "light-off" from a cold initial condition. In this work, we demonstrate a concept called "back-end catalytic ignition that potentially can be utilized in the light-off of catalytic monoliths. An external downstream flame or Joule heating raises the temperature of a small portion of the catalyst near the outlet initiating a localized catalytic reaction that propagates upstream heating the entire channel. This work uses a transient numerical model to demonstrate "back-end" ignition within a single channel which can characterize the overall performance of a monolith. The paper presents comparisons to an experiment using a single non-adiabatic channel but the concept can be extended to the adiabatic monolith case. In the model, the time scales associated with solid heat-up are typically several orders of magnitude larger than the gas-phase and chemical kinetic time-scales. Therefore, the model assumes a quasi-steady gas-phase with respect to a transient solid. The gas phase is one-dimensional. Appropriate correlations, however, account for heat and mass transfer in a direction perpendicular to the flow. The thermally-thin solid includes axial conduction. The gas phase, however, does not include axial conduction due to the high Peclet number flows. The model includes both detailed gas-phase and catalytic surface reactions. The experiment utilizes a pure platinum circular channel oriented horizontally though which a CO/O2 mixture (equivalence ratios ranging from 0.6 to 0.9) flows at 2 m/s.

Monolithic dye laser amplifier

DOEpatents

Kuklo, T.C.

1993-03-30

A fluid dye laser amplifier for amplifying a dye beam by pump beams has a channel structure defining a channel through which a laseable fluid flows and the dye and pump beams pass transversely to one another through a lasing region. The channel structure is formed with two pairs of mutually spaced-apart and mutually confronting glass windows, which are interlocked and make surface-contacts with one another and surround the lasing region. One of the glass window pairs passes the dye beam and the other passes the pump beams therethrough and through the lasing region. Where these glass window pieces make surface-contacts, glue is used to join the pieces together to form a monolithic structure so as to prevent the dye in the fluid passing through the channel from entering the space between the mutually contacting glass window pieces.

Monolithic dye laser amplifier

DOEpatents

Kuklo, Thomas C.

1993-01-01

A fluid dye laser amplifier for amplifying a dye beam by pump beams has a channel structure defining a channel through which a laseable fluid flows and the dye and pump beams pass transversely to one another through a lasing region. The channel structure is formed with two pairs of mutually spaced-apart and mutually confronting glass windows, which are interlocked and make surface-contacts with one another and surround the lasing region. One of the glass window pairs passes the dye beam and the other passes the pump beams therethrough and through the lasing region. Where these glass window pieces make surface-contacts, glue is used to join the pieces together to form a monolithic structure so as to prevent the dye in the fluid passing through the channel from entering the space between the mutually contacting glass window pieces.

Development of Matrix Microstructures in UHTC Composites

NASA Technical Reports Server (NTRS)

Johnson, Sylvia; Stackpoole, Margaret; Gusman, Michael

2012-01-01

One of the major issues hindering the use of ultra high temperature ceramics for aerospace applications is low fracture toughness. There is considerable interest in developing fiber-reinforced composites to improve fracture toughness. Considerable knowledge has been gained in controlling and improving the microstructure of monolithic UHTCs, and this paper addresses the question of transferring that knowledge to composites. Some model composites have been made and the microstructures of the matrix developed has been explored and compared to the microstructure of monolithic materials in the hafnium diboride/silicon carbide family. Both 2D and 3D weaves have been impregnated and processed.

A novel surface modification technique for forming porous polymer monoliths in poly(dimethylsiloxane).

PubMed

Burke, Jeffrey M; Smela, Elisabeth

2012-03-01

A new method of surface modification is described for enabling the in situ formation of homogenous porous polymer monoliths (PPMs) within poly(dimethylsiloxane) (PDMS) microfluidic channels that uses 365 nm UV illumination for polymerization. Porous polymer monolith formation in PDMS can be challenging because PDMS readily absorbs the monomers and solvents, changing the final monolith morphology, and because PDMS absorbs oxygen, which inhibits free-radical polymerization. The new approach is based on sequentially absorbing a non-hydrogen-abstracting photoinitiator and the monomers methyl methacrylate and ethylene diacrylate within the walls of the microchannel, and then polymerizing the surface treatment polymer within the PDMS, entangled with it but not covalently bound. Four different monolith compositions were tested, all of which yielded monoliths that were securely anchored and could withstand pressures exceeding the bonding strength of PDMS (40 psi) without dislodging. One was a recipe that was optimized to give a larger average pore size, required for low back pressure. This monolith was used to concentrate and subsequently mechanical lyse B lymphocytes.

Engineering Specification for Large-aperture UVO Space Telescopes Derived from Science Requirements

NASA Technical Reports Server (NTRS)

Stahl, H. Philip; Postman, Marc; Smith, W. Scott

2013-01-01

The Advance Mirror Technology Development (AMTD) project is a three year effort initiated in FY12 to mature by at least a half TRL step six critical technologies required to enable 4 to 8 meter UVOIR space telescope primary mirror assemblies for both general astrophysics and ultra-high contrast observations of exoplanets. AMTD uses a science-driven systems engineering approach. We mature technologies required to enable the highest priority science AND result in a high-performance low-cost low-risk system. To provide the science community with options, we are pursuing multiple technology paths. We have assembled an outstanding team from academia, industry, and government with extensive expertise in astrophysics and exoplanet characterization, and in the design/manufacture of monolithic and segmented space telescopes. A key accomplishment is deriving engineering specifications for advanced normal-incidence monolithic and segmented mirror systems needed to enable both general astrophysics and ultra-high contrast observations of exoplanets missions as a function of potential launch vehicles and their mass and volume constraints.

A 16-Channel Distributed-Feedback Laser Array with a Monolithic Integrated Arrayed Waveguide Grating Multiplexer for a Wavelength Division Multiplex-Passive Optical Network System Network

NASA Astrophysics Data System (ADS)

Zhao, Jian-Yi; Chen, Xin; Zhou, Ning; Huang, Xiao-Dong; Cao, Ming-De; Liu, Wen

2014-07-01

A 16-channel distributed-feedback (DFB) laser array with a monolithic integrated arrayed waveguide grating multiplexer for a wavelength division multiplex-passive optical network system is fabricated by using the butt-joint metal organic chemical vapor deposition technology and nanoimpirnt technology. The results show that the threshold current is about 20-30 mA at 25°C. The DFB laser side output power is about 16 mW with a 150 mA injection current. The lasing wavelength is from 1550 nm to 1575 nm covering a more than 25 nm range with 200 GHz channel space. A more than 55 dB sidemode suppression ratio is obtained.

De novo design and synthesis of ultra-short peptidomimetic antibiotics having dual antimicrobial and anti-inflammatory activities.

PubMed

Murugan, Ravichandran N; Jacob, Binu; Ahn, Mija; Hwang, Eunha; Sohn, Hoik; Park, Hyo-Nam; Lee, Eunjung; Seo, Ji-Hyung; Cheong, Chaejoon; Nam, Ky-Youb; Hyun, Jae-Kyung; Jeong, Ki-Woong; Kim, Yangmee; Shin, Song Yub; Bang, Jeong Kyu

2013-01-01

Much attention has been focused on the design and synthesis of potent, cationic antimicrobial peptides (AMPs) that possess both antimicrobial and anti-inflammatory activities. However, their development into therapeutic agents has been limited mainly due to their large size (12 to 50 residues in length) and poor protease stability. In an attempt to overcome the issues described above, a set of ultra-short, His-derived antimicrobial peptides (HDAMPs) has been developed for the first time. Through systematic tuning of pendant hydrophobic alkyl tails at the N(π)- and N(τ)-positions on His, and the positive charge of Arg, much higher prokaryotic selectivity was achieved, compared to human AMP LL-37. Additionally, the most potent HDAMPs showed promising dual antimicrobial and anti-inflammatory activities, as well as anti-methicillin-resistant Staphylococcus aureus (MRSA) activity and proteolytic resistance. Our results from transmission electron microscopy, membrane depolarization, confocal laser-scanning microscopy, and calcein-dye leakage experiments propose that HDAMP-1 kills microbial cells via dissipation of the membrane potential by forming pore/ion channels on bacterial cell membranes. The combination of the ultra-short size, high-prokaryotic selectivity, potent anti-MRSA activity, anti-inflammatory activity, and proteolytic resistance of the designed HDAMP-1, -3, -5, and -6 makes these molecules promising candidates for future antimicrobial therapeutics.

2D Quantum Simulation of MOSFET Using the Non Equilibrium Green's Function Method

NASA Technical Reports Server (NTRS)

Svizhenko, Alexel; Anantram, M. P.; Govindan, T. R.; Yan, Jerry (Technical Monitor)

2000-01-01

The objectives this viewgraph presentation summarizes include: (1) the development of a quantum mechanical simulator for ultra short channel MOSFET simulation, including theory, physical approximations, and computer code; (2) explore physics that is not accessible by semiclassical methods; (3) benchmarking of semiclassical and classical methods; and (4) study other two-dimensional devices and molecular structure, from discretized Hamiltonian to tight-binding Hamiltonian.

Experimental demonstration of monolithically integrated 16 channel DFB laser array fabricated by nanoimprint lithography with AWG multiplexer and SOA for WDM-PON application

NASA Astrophysics Data System (ADS)

Zhao, Jianyi; Chen, Xin; Zhou, Ning; Huang, Xiaodong; Cao, Mingde; Wang, Lei; Liu, Wen

2015-03-01

A 16-channel monolithically integrated distributed feedback (DFB) laser array with arrayed waveguide gratings (AWGs) multiplexer and semiconductor optical amplifier (SOA) has been fabricated using nanoimprint technology. Selective lasing wavelength with 200 GHz frequency space has been obtained. The typical threshold current is between 20 mA and 30 mA. The output power is higher than 1 mW with 350 mA current in SOA. The side mode suppression ratio (SMSR) of the spectrum is better than 40 dB.

Comparison of Reactive and Non-Reactive Spark Plasma Sintering Routes for the Fabrication of Monolithic and Composite Ultra High Temperature Ceramics (UHTC) Materials

PubMed Central

Orrù, Roberto; Cao, Giacomo

2013-01-01

A wider utilization of ultra high temperature ceramics (UHTC) materials strongly depends on the availability of efficient techniques for their fabrication as dense bodies. Based on recent results reported in the literature, it is possible to state that Spark Plasma Sintering (SPS) technology offers a useful contribution in this direction. Along these lines, the use of two different SPS-based processing routes for the preparation of massive UHTCs is examined in this work. One method, the so-called reactive SPS (R-SPS), consists of the synthesis and densification of the material in a single step. Alternatively, the ceramic powders are first synthesized by Self-propagating High-temperature Synthesis (SHS) and then sintered by SPS. The obtained results evidenced that R-SPS method is preferable for the preparation of dense monolithic products, while the sintering of SHS powders requires relatively milder conditions when considering binary composites. The different kinetic mechanisms involved during R-SPS of the monolithic and composite systems, i.e., combustion-like or gradual solid-diffusion, respectively, provides a possible explanation. An important role is also played by the SHS process, particularly for the preparation of composite powders, since stronger interfaces are established between the ceramic constituents formed in situ, thus favoring diffusion processes during the subsequent SPS step. PMID:28809229

All-optical SR flip-flop based on SOA-MZI switches monolithically integrated on a generic InP platform

NASA Astrophysics Data System (ADS)

Pitris, St.; Vagionas, Ch.; Kanellos, G. T.; Kisacik, R.; Tekin, T.; Broeke, R.; Pleros, N.

2016-03-01

At the dawning of the exaflop era, High Performance Computers are foreseen to exploit integrated all-optical elements, to overcome the speed limitations imposed by electronic counterparts. Drawing from the well-known Memory Wall limitation, imposing a performance gap between processor and memory speeds, research has focused on developing ultra-fast latching devices and all-optical memory elements capable of delivering buffering and switching functionalities at unprecedented bit-rates. Following the master-slave configuration of electronic Flip-Flops, coupled SOA-MZI based switches have been theoretically investigated to exceed 40 Gb/s operation, provided a short coupling waveguide. However, this flip-flop architecture has been only hybridly integrated with silica-on-silicon integration technology exhibiting a total footprint of 45x12 mm2 and intra-Flip-Flop coupling waveguide of 2.5cm, limited at 5 Gb/s operation. Monolithic integration offers the possibility to fabricate multiple active and passive photonic components on a single chip at a close proximity towards, bearing promises for fast all-optical memories. Here, we present for the first time a monolithically integrated all-optical SR Flip-Flop with coupled master-slave SOA-MZI switches. The photonic chip is integrated on a 6x2 mm2 die as a part of a multi-project wafer run using library based components of a generic InP platform, fiber-pigtailed and fully packaged on a temperature controlled ceramic submount module with electrical contacts. The intra Flip-Flop coupling waveguide is 5 mm long, reducing the total footprint by two orders of magnitude. Successful flip flop functionality is evaluated at 10 Gb/s with clear open eye diagram, achieving error free operation with a power penalty of 4dB.

New control strategies with inertial monolithic sensors: advantages and limitations in the control of benches and platforms for seismic isolation

NASA Astrophysics Data System (ADS)

Barone, F.; Giordano, G.; Acernese, F.; Romano, R.

2018-03-01

In this paper, we present some innovative and general strategies for the control of benches and platforms, that the introduction of the new class of monolithic UNISA Folded Pendulum is now making it possible, also in terms of environmental conditions, like ultra-high-vacuum (UHV), cryogenics and harsh environments. In particular, we present and discuss a parametric analysis of the control models in connection with the sensors limitations in terms of sensitivity and band. Finally, we present and discuss some experimental laboratory tests on a laboratory platform, underlining the present advantages and the expected future improvements.

Cascaded Brillouin lasing in monolithic barium fluoride whispering gallery mode resonators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Guoping, E-mail: guoping.lin@femto-st.fr; Diallo, Souleymane; Saleh, Khaldoun

2014-12-08

We report the observation of stimulated Brillouin scattering and lasing at 1550 nm in barium fluoride (BaF{sub 2}) crystal. Brillouin lasing was achieved with ultra-high quality (Q) factor monolithic whispering gallery mode mm-size disk resonators. Overmoded resonators were specifically used to provide cavity resonances for both the pump and all Brillouin Stokes waves. Single and multiple Brillouin Stokes radiations with frequency shift ranging from 8.2 GHz up to 49 GHz have been generated through cascaded Brillouin lasing. BaF{sub 2} resonator-based Brillouin lasing can find potential applications for high-coherence lasers and microwave photonics.

Photonic crystal fiber technology for high-performance all-fiber monolithic ultrafast fiber amplifiers

NASA Astrophysics Data System (ADS)

Papior, Sidsel R.; Weirich, Johannes; Johansen, Mette M.; Jakobsen, Christian; Michieletto, Mattia; Triches, Marco; Kristensen, Torben; Olesen, Anders S.; Petersen, Christian; Andersen, Thomas V.; Maack, Martin D.; Alkeskjold, Thomas T.

2018-02-01

Photonic crystal fiber (PCF) technology for ultrafast fiber amplifiers traditionally uses air holes as key elements for large mode area (LMA) fiber designs. These air holes are crucial for the performance of high-end LMA PCFs, but makes splicing and interfacing more complex. To reduce this complexity in mid-range amplifiers, we present single-mode polarization-maintaining Yb-doped LMA PCFs without air holes for easier splicing into monolithic all-fiber amplifier designs. A 30 μm core all-solid spliceable PCF is presented, and amplification of 1064 nm light above 50 W with an optical to optical efficiency of 80 % is demonstrated. Furthermore, to demonstrate the excellent reliability of PCF based monolithic amplifiers, we demonstrate ultra-longterm performance data of > 35 khrs on a 14 μm core step-index type PCF amplifier with low long-term power degradation slope of < 1.5 % / 10,000 h.

The prototype of the Micro Vertex Detector of the CBM Experiment

NASA Astrophysics Data System (ADS)

Koziel, Michal; Amar-Youcef, Samir; Bialas, Norbert; Deveaux, Michael; Fröhlich, Ingo; Li, Qiyan; Michel, Jan; Milanović, Borislav; Müntz, Christian; Neumann, Bertram; Schrader, Christoph; Stroth, Joachim; Tischler, Tobias; Weirich, Roland; Wiebusch, Michael

2013-12-01

The Compressed Baryonic Matter (CBM) Experiment is one of the core experiments of the future FAIR facility at Darmstadt, Germany. This fixed-target experiment will explore the phase diagram of strongly interacting matter in the regime of highest net baryon densities with numerous probes, among them open charm. Reconstructing those short lived particles requires a vacuum compatible Micro Vertex Detector (MVD) with unprecedented properties. Its sensor technology has to feature a spatial resolution of <5 μm, a non-ionizing radiation tolerance of >1013 neq/cm2, an ionizing radiation tolerance of >3 Mrad and a time resolution of a few 10 μs. The MVD-prototype project aimed to study the integration the CMOS Monolithic Active Pixel Sensors foreseen for the MVD into an ultra light (0.3% X0) and a vacuum compatible detector system based on a cooling support made of CVD-diamond.

Effects of ultra-thin Si-fin body widths upon SOI PMOS FinFETs

NASA Astrophysics Data System (ADS)

Liaw, Yue-Gie; Chen, Chii-Wen; Liao, Wen-Shiang; Wang, Mu-Chun; Zou, Xuecheng

2018-05-01

Nano-node tri-gate FinFET devices have been developed after integrating a 14 Å nitrided gate oxide upon the silicon-on-insulator (SOI) wafers established on an advanced CMOS logic platform. These vertical double gate (FinFET) devices with ultra-thin silicon fin (Si-fin) widths ranging from 27 nm to 17 nm and gate length down to 30 nm have been successfully developed with a 193 nm scanner lithography tool. Combining the cobalt fully silicidation and the CESL strain technology beneficial for PMOS FinFETs was incorporated into this work. Detailed analyses of Id-Vg characteristics, threshold voltage (Vt), and drain-induced barrier lowering (DIBL) illustrate that the thinnest 17 nm Si-fin width FinFET exhibits the best gate controllability due to its better suppression of short channel effect (SCE). However, higher source/drain resistance (RSD), channel mobility degradation due to dry etch steps, or “current crowding effect” will slightly limit its transconductance (Gm) and drive current.

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Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-17

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Titanium-scaffolded organic-monolithic stationary phases for ultra-high-pressure liquid chromatography.

PubMed

Vonk, Rudy J; Vaast, Axel; Eeltink, Sebastiaan; Schoenmakers, Peter J

2014-09-12

Organic-polymer monoliths with overall dimensions larger than one millimetre are prone to rupture - either within the monolith itself or between the monoliths and the containing wall - due to the inevitable shrinkage accompanying the formation of a cross-linked polymeric network. This problem has been addressed by creating titanium-scaffolded poly(styrene-co-divinylbenzene) (S-co-DVB) monoliths. Titanium-scaffolded monoliths were successfully used in liquid chromatography at very high pressures (up to 80MPa) and using gradients spanning the full range of water-acetonitrile compositions (0 to 100%). The kinetic-performance of (50-mm long) titanium-scaffolded monoliths was compared to that of similar monolith created in 1-mm i.d. glass-lined tubing at pressures up to 50MPa. The peak capacities obtained with the titanium-scaffolded column was about 30% lower. An increased Eddy-diffusion, due to the pillar-structure, and a decreased permeability are thought to be the main reasons for this reduced kinetic-performance. No decrease in performance was observed when the titanium-scaffolded columns were operated at pressures of 80MPa for up to 12h. The column-to-column repeatability (n=5) was acceptable in terms of observed peak widths at half heights (RSD ca. 10%) The run-to-run repeatability (n=135) in terms of retention times and peak widths at half height were found to be good. Titanium-scaffolded columns coupled in series up to a combined length of (200mm) were used for the analyses of a complex Escherichia coli protein sample. Our experiments demonstrate that columns based on titanium-scaffolded organic-polymer monolith can be operated under strenuous conditions without loss in performance. The titanium-scaffolded approach makes it feasible to create organic-polymer monoliths in wide-bore columns with accurate temperature control. Copyright © 2014 Elsevier B.V. All rights reserved.

Novel Process for Removal and Recovery of Vapor Phase Mercury

DOE Office of Scientific and Technical Information (OSTI.GOV)

Greenwell, Collin; Roberts, Daryl L; Albiston, Jason

We demonstrated in the Phase I program all key attributes of a new technology for removing mercury from flue gases, namely, a) removal of greater than 95% of both elemental and oxidized forms of mercury, both in the laboratory and in the field b) regenerability of the sorbent c) ability to scale up, and d) favorable economics. The Phase I program consisted of four tasks other than project reporting: Task I-1 Screen Sorbent Configurations in the Laboratory Task I-2 Design and Fabricate Bench-Scale Equipment Task I-3 Test Bench-Scale Equipment on Pilot Combustor Task I-4 Evaluate Economics Based on Bench-Scale Resultsmore » In Task I-1, we demonstrated that the sorbents are thermally durable and are regenerable through at least 55 cycles of mercury uptake and desorption. We also demonstrated two low-pressure- drop configurations of the sorbent, namely, a particulate form and a monolithic form. We showed that the particulate form of the sorbent would take up 100% of the mercury so long as the residence time in a bed of the sorbent exceeded 0.1 seconds. In principle, the particulate form of the sorbent could be imbedded in the back side of a higher temperature bag filter in a full-scale application. With typical bag face velocities of four feet per minute, the thickness of the particulate layer would need to be about 2000 microns to accomplish the uptake of the mercury. For heat transfer efficiency, however, we believed the monolithic form of the sorbent would be the more practical in a full scale application. Therefore, we purchased commercially-available metallic monoliths and applied the sorbent to the inside of the flow channels of the monoliths. At face velocities we tested (up to 1.5 ft/sec), these monoliths had less than 0.05 inches of water pressure drop. We tested the monolithic form of the sorbent through 21 cycles of mercury sorption and desorption in the laboratory and included a test of simultaneous uptake of both mercury and mercuric chloride. Overall, in Task I-1, we found that the particulate and monolith forms of the sorbent were thermally stable and durable and would repeatedly sorb and desorb 100% of the mercury, including mercuric chloride, with low pressure drop and short residence times at realistic flue gas conditions.« less

Monolithic graphene transistor biointerface.

PubMed

Nam, SungWoo; Lee, Mi-Sun; Park, Jang-Ung

2012-01-01

We report monolithic integration of graphene and graphite for all-carbon integrated bioelectronics. First, we demonstrate that the electrical properties of graphene and graphite can be modulated by controlling the number of graphene layers, and such capabilities allow graphene to be used as active channels and graphite as metallic interconnects for all-carbon bioelectronics. Furthermore, we show that monolithic graphene-graphite devices exhibit mechanical flexibility and robustness while their electrical responses are not perturbed by mechanical deformation, demonstrating their unique electromechanical properties. Chemical sensing capability of all-carbon integrated bioelectronics is manifested in real-time, complementary pH detection. These unique capabilities of our monolithic graphene-graphite bioelectronics could be exploited in chemical and biological detection and conformal interface with biological systems in the future.

Advanced digital modulation: Communication techniques and monolithic GaAs technology

NASA Technical Reports Server (NTRS)

Wilson, S. G.; Oliver, J. D., Jr.; Kot, R. C.; Richards, C. R.

1983-01-01

Communications theory and practice are merged with state-of-the-art technology in IC fabrication, especially monolithic GaAs technology, to examine the general feasibility of a number of advanced technology digital transmission systems. Satellite-channel models with (1) superior throughput, perhaps 2 Gbps; (2) attractive weight and cost; and (3) high RF power and spectrum efficiency are discussed. Transmission techniques possessing reasonably simple architectures capable of monolithic fabrication at high speeds were surveyed. This included a review of amplitude/phase shift keying (APSK) techniques and the continuous-phase-modulation (CPM) methods, of which MSK represents the simplest case.

De Novo Design and Synthesis of Ultra-Short Peptidomimetic Antibiotics Having Dual Antimicrobial and Anti-Inflammatory Activities

PubMed Central

Ahn, Mija; Hwang, Eunha; Sohn, Hoik; Park, Hyo-Nam; Lee, Eunjung; Seo, Ji-Hyung; Cheong, Chaejoon; Nam, Ky-Youb; Hyun, Jae-Kyung; Jeong, Ki-Woong; Kim, Yangmee; Shin, Song Yub; Bang, Jeong Kyu

2013-01-01

Background Much attention has been focused on the design and synthesis of potent, cationic antimicrobial peptides (AMPs) that possess both antimicrobial and anti-inflammatory activities. However, their development into therapeutic agents has been limited mainly due to their large size (12 to 50 residues in length) and poor protease stability. Methodology/Principal Findings In an attempt to overcome the issues described above, a set of ultra-short, His-derived antimicrobial peptides (HDAMPs) has been developed for the first time. Through systematic tuning of pendant hydrophobic alkyl tails at the N(π)- and N(τ)-positions on His, and the positive charge of Arg, much higher prokaryotic selectivity was achieved, compared to human AMP LL-37. Additionally, the most potent HDAMPs showed promising dual antimicrobial and anti-inflammatory activities, as well as anti–methicillin-resistant Staphylococcus aureus (MRSA) activity and proteolytic resistance. Our results from transmission electron microscopy, membrane depolarization, confocal laser-scanning microscopy, and calcein-dye leakage experiments propose that HDAMP-1 kills microbial cells via dissipation of the membrane potential by forming pore/ion channels on bacterial cell membranes. Conclusion/Significance The combination of the ultra-short size, high-prokaryotic selectivity, potent anti-MRSA activity, anti-inflammatory activity, and proteolytic resistance of the designed HDAMP-1, -3, -5, and -6 makes these molecules promising candidates for future antimicrobial therapeutics. PMID:24302996

Sustainable one step process for making carbon-free TiO 2 anodes and sodium-ion battery electrochemistry

DOE PAGES

Chadha, Tandeep S.; Dutta, Prasit Kumar; Raliya, Ramesh; ...

2018-01-01

The ultra durable monolithic dendritic anatase TiO 2 provides a mechanistic inner-view via a rotational moiré pattern, resulting in 99.55% coulombic efficiency with only 41 mV polarization loss at the 1000 th cycle, while retaining the columnar morphology.

Sustainable one step process for making carbon-free TiO 2 anodes and sodium-ion battery electrochemistry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chadha, Tandeep S.; Dutta, Prasit Kumar; Raliya, Ramesh

The ultra durable monolithic dendritic anatase TiO 2 provides a mechanistic inner-view via a rotational moiré pattern, resulting in 99.55% coulombic efficiency with only 41 mV polarization loss at the 1000 th cycle, while retaining the columnar morphology.

Optoelectronic devices toward monolithic integration

NASA Astrophysics Data System (ADS)

Ghergia, V.

1992-12-01

Starting from the present state of tl art of discrete devices up to the on going realization of monolithic semicorxtuctor integrated prototypes an overview ofoptoelectronic devices for telecom applications is given inchiding a short classification of the different kind of integrated devices. On the future perspective of IBCN distribution network some economica of hybrid and monolithic forms of integration are attempted. lnaflyashoitpresentationoftheactivitiesperformedintbefieldofmonolithic integration by EEC ESPR1T and RACE projects is reported. 1.

A dc amplifier for nuclear particle measurement

NASA Technical Reports Server (NTRS)

Macnee, A. B.; Masnari, N. A.

1978-01-01

A monolithic preamplifier-postamplifier combination has been developed for use with solid state particle detectors. The direct coupled amplifiers employ interdigitated n-channel JFET's, diodes, and diffused resistors. The circuits developed demonstrate the feasibility of matching the performance of existing discrete component designs. The fabrication procedures for the monolithic amplifier fabrication are presented and the results of measurements on a limited number of sample amplifiers are given.

Catalytic Ignition and Upstream Reaction Propagation in Monolith Reactors

NASA Technical Reports Server (NTRS)

Struk, Peter M.; Dietrich, Daniel L.; Miller, Fletcher J.; T'ien, James S.

2007-01-01

Using numerical simulations, this work demonstrates a concept called back-end ignition for lighting-off and pre-heating a catalytic monolith in a power generation system. In this concept, a downstream heat source (e.g. a flame) or resistive heating in the downstream portion of the monolith initiates a localized catalytic reaction which subsequently propagates upstream and heats the entire monolith. The simulations used a transient numerical model of a single catalytic channel which characterizes the behavior of the entire monolith. The model treats both the gas and solid phases and includes detailed homogeneous and heterogeneous reactions. An important parameter in the model for back-end ignition is upstream heat conduction along the solid. The simulations used both dry and wet CO chemistry as a model fuel for the proof-of-concept calculations; the presence of water vapor can trigger homogenous reactions, provided that gas-phase temperatures are adequately high and there is sufficient fuel remaining after surface reactions. With sufficiently high inlet equivalence ratio, back-end ignition occurs using the thermophysical properties of both a ceramic and metal monolith (coated with platinum in both cases), with the heat-up times significantly faster for the metal monolith. For lower equivalence ratios, back-end ignition occurs without upstream propagation. Once light-off and propagation occur, the inlet equivalence ratio could be reduced significantly while still maintaining an ignited monolith as demonstrated by calculations using complete monolith heating.

Monolithic poly(1,2-bis(p-vinylphenyl)ethane) capillary columns for simultaneous separation of low- and high-molecular-weight compounds.

PubMed

Greiderer, Andreas; Ligon, S Clark; Huck, Christian W; Bonn, Günther K

2009-08-01

Monolithic poly(1,2-bis(p-vinylphenyl)ethane (BVPE)) capillary columns were prepared by thermally initiated free radical polymerisation of 1,2-bis(p-vinylphenyl)ethane in the presence of inert diluents (porogens) and alpha,alpha'-azoisobutyronitrile (AIBN) as initiator. Polymerisations were accomplished in 200 microm ID fused silica capillaries at 65 degrees C and for 60 min. Mercury intrusion porosimetry measurements of the polymeric RP support showed a broad bimodal pore-size-distribution of mesopores and small macropores in the range of 5-400 nm and flow-channels in the mum range. N(2)-adsorption (BET) analysis resulted in a tremendous enhancement of surface area (101 m(2)/g) of BVPE stationary phases compared to typical organic monoliths (approximately 20 m(2)/g), indicating the presence of a considerable amount of mesopores. Consequently, the adequate proportion of both meso- and (small) macropores allowed the rapid and high-resolution separation of low-molecular-weight compounds as well as biomolecules on the same monolithic support. At the same time, the high fraction of flow-channels provided enhanced column permeability. The chromatographic performance of poly(1,2-bis(p-vinylphenyl)ethane) capillary columns for the separation of biomolecules (proteins, oligonucleotides) and small molecules (alkyl benzenes, phenols, phenons) are demonstrated in this article. Additionally, pressure drop versus flow rate measurements of novel poly(1,2-bis(p-vinylphenyl)ethane) capillary columns confirmed high mechanical robustness, low swelling in organic solvents and high permeability. Due to the simplicity of monolith fabrication, comprehensive studies of the retention and separation behaviour of monolithic BVPE columns resulted in high run-to-run and batch-to-batch reproducibilities. All these attributes prove the excellent applicability of monolithic poly(1,2-bis(p-vinylphenyl)ethane) capillary columns for micro-HPLC towards a huge range of analytes of different chemistries and molecular sizes.

Compact vacuum insulation embodiments

DOEpatents

Benson, D.K.; Potter, T.F.

1992-04-28

An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom to form essentially point' or line' contacts with the metal wall sheets. In the case of monolithic spacers that form line' contacts, two such spacers with the line contacts running perpendicular to each other form effectively point' contacts at the intersections. Corrugations accommodate bending and expansion, tubular insulated pipes and conduits, and preferred applications are also included. 26 figs.

Compact vacuum insulation

DOEpatents

Benson, D.K.; Potter, T.F.

1993-01-05

An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom to form essentially point'' or line'' contacts with the metal wall sheets. In the case of monolithic spacers that form line'' contacts, two such spacers with the line contacts running perpendicular to each other form effectively point'' contacts at the intersections. Corrugations accommodate bending and expansion, tubular insulated pipes and conduits, and preferred applications are also included.

A new class of monolithic seismometers and accelerometers for commercial and industrial applications: the UNISA folded pendulum

NASA Astrophysics Data System (ADS)

Barone, F.; Giordano, G.

2017-04-01

In this paper we present monolithic implementations of tunable mechanical seismometers and accelerometers (horizontal, vertical and angular) based on the UNISA Folded Pendulum configuration, protected by three international patents and commercially available. Typical characteristics are measurement band 10-7 / 1kHz, sensitivity down to ≍ 10-15 m/ √ Hz, directivity > 104, weight < 1.5 kg, dimensions < 10 cm, coupled to a large insensitivity to environmental noises and capability of operating in ultra high vacuum and cryogenic environments. Typical applications of this class of sensors are in the field of earthquake engineering, seismology, geophysics, civil engineering (buildings, bridges, dams, etc.), space (inertial guide).

Compact vacuum insulation

DOEpatents

Benson, David K.; Potter, Thomas F.

1993-01-01

An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom to form essentially "point" or "line" contacts with the metal wall sheets. In the case of monolithic spacers that form "line" contacts, two such spacers with the line contacts running perpendicular to each other form effectively "point" contacts at the intersections. Corrugations accommodate bending and expansion, tubular insulated pipes and conduits, and preferred applications are also included.

Compact vacuum insulation embodiments

DOEpatents

Benson, David K.; Potter, Thomas F.

1992-01-01

An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom to form essentially "point" or "line" contacts with the metal wall sheets. In the case of monolithic spacers that form "line" contacts, two such spacers with the line contacts running perpendicular to each other form effectively "point" contacts at the intersections. Corrugations accommodate bending and expansion, tubular insulated pipes and conduits, and preferred applications are also included.

An Ultra-Low Power and Flexible Acoustic Modem Design to Develop Energy-Efficient Underwater Sensor Networks

PubMed Central

Sánchez, Antonio; Blanc, Sara; Yuste, Pedro; Perles, Angel; Serrano, Juan José

2012-01-01

This paper is focused on the description of the physical layer of a new acoustic modem called ITACA. The modem architecture includes as a major novelty an ultra-low power asynchronous wake-up system implementation for underwater acoustic transmission that is based on a low-cost off-the-shelf RFID peripheral integrated circuit. This feature enables a reduced power dissipation of 10 μW in stand-by mode and registers very low power values during reception and transmission. The modem also incorporates clear channel assessment (CCA) to support CSMA-based medium access control (MAC) layer protocols. The design is part of a compact platform for a long-life short/medium range underwater wireless sensor network. PMID:22969324

An ultra-low power and flexible acoustic modem design to develop energy-efficient underwater sensor networks.

PubMed

Sánchez, Antonio; Blanc, Sara; Yuste, Pedro; Perles, Angel; Serrano, Juan José

2012-01-01

This paper is focused on the description of the physical layer of a new acoustic modem called ITACA. The modem architecture includes as a major novelty an ultra-low power asynchronous wake-up system implementation for underwater acoustic transmission that is based on a low-cost off-the-shelf RFID peripheral integrated circuit. This feature enables a reduced power dissipation of 10 μW in stand-by mode and registers very low power values during reception and transmission. The modem also incorporates clear channel assessment (CCA) to support CSMA-based medium access control (MAC) layer protocols. The design is part of a compact platform for a long-life short/medium range underwater wireless sensor network.

The significance of ultra-refracted surface gravity waves on sheltered coasts, with application to San Francisco Bay

USGS Publications Warehouse

Hanes, D.M.; Erikson, L.H.

2013-01-01

Ocean surface gravity waves propagating over shallow bathymetry undergo spatial modification of propagation direction and energy density, commonly due to refraction and shoaling. If the bathymetric variations are significant the waves can undergo changes in their direction of propagation (relative to deepwater) greater than 90° over relatively short spatial scales. We refer to this phenomenon as ultra-refraction. Ultra-refracted swell waves can have a powerful influence on coastal areas that otherwise appear to be sheltered from ocean waves. Through a numerical modeling investigation it is shown that San Francisco Bay, one of the earth's largest and most protected natural harbors, is vulnerable to ultra-refracted ocean waves, particularly southwest incident swell. The flux of wave energy into San Francisco Bay results from wave transformation due to the bathymetry and orientation of the large ebb tidal delta, and deep, narrow channel through the Golden Gate. For example, ultra-refracted swell waves play a critical role in the intermittent closure of the entrance to Crissy Field Marsh, a small restored tidal wetland located on the sheltered north-facing coast approximately 1.5 km east of the Golden Gate Bridge.

Towards sparse characterisation of on-body ultra-wideband wireless channels.

PubMed

Yang, Xiaodong; Ren, Aifeng; Zhang, Zhiya; Ur Rehman, Masood; Abbasi, Qammer Hussain; Alomainy, Akram

2015-06-01

With the aim of reducing cost and power consumption of the receiving terminal, compressive sensing (CS) framework is applied to on-body ultra-wideband (UWB) channel estimation. It is demonstrated in this Letter that the sparse on-body UWB channel impulse response recovered by the CS framework fits the original sparse channel well; thus, on-body channel estimation can be achieved using low-speed sampling devices.

Towards sparse characterisation of on-body ultra-wideband wireless channels

PubMed Central

Ren, Aifeng; Zhang, Zhiya; Ur Rehman, Masood; Abbasi, Qammer Hussain; Alomainy, Akram

2015-01-01

With the aim of reducing cost and power consumption of the receiving terminal, compressive sensing (CS) framework is applied to on-body ultra-wideband (UWB) channel estimation. It is demonstrated in this Letter that the sparse on-body UWB channel impulse response recovered by the CS framework fits the original sparse channel well; thus, on-body channel estimation can be achieved using low-speed sampling devices. PMID:26609409

Monolithic circuits for barium fluoride detectors used in nuclear physics experiments. CRADA final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Varner, R.L.; Blankenship, J.L.; Beene, J.R.

1998-02-01

Custom monolithic electronic circuits have been developed recently for large detector applications in high energy physics where subsystems require tens of thousands of channels of signal processing and data acquisition. In the design and construction of these enormous detectors, it has been found that monolithic circuits offer significant advantages over discrete implementations through increased performance, flexible packaging, lower power and reduced cost per channel. Much of the integrated circuit design for the high energy physics community is directly applicable to intermediate energy heavy-ion and electron physics. This STTR project conducted in collaboration with researchers at the Holifield Radioactive Ion Beammore » Facility (HRIBF) at Oak Ridge National Laboratory, sought to develop a new integrated circuit chip set for barium fluoride (BaF{sub 2}) detector arrays based upon existing CMOS monolithic circuit designs created for the high energy physics experiments. The work under the STTR Phase 1 demonstrated through the design, simulation, and testing of several prototype chips the feasibility of using custom CMOS integrated circuits for processing signals from BaF{sub 2} detectors. Function blocks including charge-sensitive amplifiers, comparators, one shots, time-to-amplitude converters, analog memory circuits and buffer amplifiers were implemented during Phase 1 effort. Experimental results from bench testing and laboratory testing with sources were documented.« less

Poly(ethylenimine)-Functionalized Monolithic Alumina Honeycomb Adsorbents for CO2 Capture from Air.

PubMed

Sakwa-Novak, Miles A; Yoo, Chun-Jae; Tan, Shuai; Rashidi, Fereshteh; Jones, Christopher W

2016-07-21

The development of practical and effective gas-solid contactors is an important area in the development of CO2 capture technologies. Target CO2 capture applications, such as postcombustion carbon capture and sequestration (CCS) from power plant flue gases or CO2 extraction directly from ambient air (DAC), require high flow rates of gas to be processed at low cost. Extruded monolithic honeycomb structures, such as those employed in the catalytic converters of automobiles, have excellent potential as structured contactors for CO2 adsorption applications because of the low pressure drop imposed on fluid moving through the straight channels of such structures. Here, we report the impregnation of poly(ethylenimine) (PEI), an effective aminopolymer reported commonly for CO2 separation, into extruded monolithic alumina to form structured CO2 sorbents. These structured sorbents are first prepared on a small scale, characterized thoroughly, and compared with powder sorbents with a similar composition. Despite consistent differences observed in the filling of mesopores with PEI between the monolithic and powder sorbents, their performance in CO2 adsorption is similar across a range of PEI contents. A larger monolithic cylinder (1 inch diameter, 4 inch length) is evaluated under conditions closer to those that might be used in large-scale applications and shows a similar performance to the smaller monoliths and powders tested initially. This larger structure is evaluated over five cycles of CO2 adsorption and steam desorption and demonstrates a volumetric capacity of 350 molCO2  m-3monolith and an equilibration time of 350 min under a 0.4 m s(-1) linear flow velocity through the monolith channels using 400 ppm CO2 in N2 as the adsorption gas at 30 °C. This volumetric capacity surpasses that of a similar technology considered previously, which suggested that CO2 could be removed from air at an operating cost as low as $100 per ton. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Macroporous Monolithic Polymers: Preparation and Applications

PubMed Central

Arrua, Ruben Dario; Strumia, Miriam Cristina; Alvarez Igarzabal, Cecilia Inés

2009-01-01

In the last years, macroporous monolithic materials have been introduced as a new and useful generation of polymers used in different fields. These polymers may be prepared in a simple way from a homogenous mixture into a mold and contain large interconnected pores or channels allowing for high flow rates at moderate pressures. Due to their porous characteristics, they could be used in different processes, such as stationary phases for different types of chromatography, high-throughput bioreactors and in microfluidic chip applications. This review reports the contributions of several groups working in the preparation of different macroporous monoliths and their modification by immobilization of specific ligands on the products for specific purposes.

Polymethacrylate-based monoliths as stationary phases for separation of biopolymers and immobilization of enzymes.

PubMed

Martinović, Tamara; Josić, Djuro

2017-11-01

The experiences in the production and application of polymethacrylate-based monolithic supports, since their development almost thirty years ago, are presented. The main driving force for the development of new chromatographic supports was the necessity for the isolation and separation of physiologically active biopolymers and their use for therapeutic purposes. For this sake, a development of a method for fast separation, preventing denaturation and preserving their biological activity was necessary. Development of polysaccharide-based supports, followed by the introduction of polymer-based chromatographic media, is shortly described. This development was followed by the advances in monolithic media that are now used for both large- and small-scale separation of biopolymers and nanoparticles. Finally, a short overview is given about the applications of monoliths for sample displacement chromatography, resulting in isolation of physiologically active biomolecules, such as proteins, protein complexes, and nucleic acid, as well as high-throughput sample preparation for proteomic investigations. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

75 FR 32531 - Self-Regulatory Organizations; International Securities Exchange, LLC; Notice of Filing and...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-08

.... Currently, the First Trust ISE Water ETF (``FIW''), the Claymore China Technology ETF (``CQQQ''), the ProShares UltraPro Short Dow30 (``SDOW''), the ProShares UltraPro Dow30 (``UDOW''), the ProShares UltraPro Short MidCap400 (``SMDD''), the ProShares UltraPro MidCap400 (``UMDD''), the ProShares UltraPro Short...

Monolithic microchannel heatsink

DOEpatents

Benett, W.J.; Beach, R.J.; Ciarlo, D.R.

1996-08-20

A silicon wafer has slots sawn in it that allow diode laser bars to be mounted in contact with the silicon. Microchannels are etched into the back of the wafer to provide cooling of the diode bars. To facilitate getting the channels close to the diode bars, the channels are rotated from an angle perpendicular to the diode bars which allows increased penetration between the mounted diode bars. This invention enables the fabrication of monolithic silicon microchannel heatsinks for laser diodes. The heatsinks have low thermal resistance because of the close proximity of the microchannels to the laser diode being cooled. This allows high average power operation of two-dimensional laser diode arrays that have a high density of laser diode bars and therefore high optical power density. 9 figs.

Monolithic microchannel heatsink

DOEpatents

Benett, William J.; Beach, Raymond J.; Ciarlo, Dino R.

1996-01-01

A silicon wafer has slots sawn in it that allow diode laser bars to be mounted in contact with the silicon. Microchannels are etched into the back of the wafer to provide cooling of the diode bars. To facilitate getting the channels close to the diode bars, the channels are rotated from an angle perpendicular to the diode bars which allows increased penetration between the mounted diode bars. This invention enables the fabrication of monolithic silicon microchannel heatsinks for laser diodes. The heatsinks have low thermal resistance because of the close proximity of the microchannels to the laser diode being cooled. This allows high average power operation of two-dimensional laser diode arrays that have a high density of laser diode bars and therefore high optical power density.

Photonic generation of ultra-wide-band doublet pulse through monolithic integration of tapered directional coupler and quantum well waveguide.

PubMed

Kuo, Yu-Zheng; Wu, Jui-Pin; Wu, Tsu-Hsiu; Chiu, Yi-Jen

2012-10-22

We proposed and demonstrated a novel scheme of photonic ultra-wide-band (UWB) doublet pulse based on monolithic integration of tapered optical-direction coupler (TODC) and multiple-quantum-well (MQW) waveguide. TODC is formed by a top tapered MQW waveguide vertically integrating with an underneath passive waveguide. Through simultaneous field-driven optical index- and absorption- change in MQW, the partial optical coupling in TODC can be used to get a valley-shaped of optical transmission against voltage. Therefore, doublet-enveloped optical pulse can be realized by high-speed and high-efficient conversion of input electrical pulse. By just adjusting bias through MQW, 1530 nm photonic UWB doublet optical pulse with 75-ps pulse width, below -41.3 dBm power, 125% fractional bandwidth, and 7.5 GHz of -10 dB bandwidth has been demonstrated, fitted into FCC requirement (3.1 GHz~10.6 GHz). Doublet-pulse data transmission generated in optical fiber is also performed for further characterization, exhibiting a successful 1.25 Gb/s error-free transmission. It suggests such optoelectronic integration template can be applied for photonic UWB generation in fiber-based communications.

Transparent Ultra-High-Loading Quantum Dot/Polymer Nanocomposite Monolith for Gamma Scintillation.

PubMed

Liu, Chao; Li, Zhou; Hajagos, Tibor Jacob; Kishpaugh, David; Chen, Dustin Yuan; Pei, Qibing

2017-06-27

Spectroscopic gamma-photon detection has widespread applications for research, defense, and medical purposes. However, current commercial detectors are either prohibitively expensive for wide deployment or incapable of producing the characteristic gamma photopeak. Here we report the synthesis of transparent, ultra-high-loading (up to 60 wt %) Cd x Zn 1-x S/ZnS core/shell quantum dot/polymer nanocomposite monoliths for gamma scintillation by in situ copolymerization of the partially methacrylate-functionalized quantum dots in a monomer solution. The efficient Förster resonance energy transfer of the high-atomic-number quantum dots to lower-band-gap organic dyes enables the extraction of quantum-dot-borne excitons for photon production, resolving the problem of severe light yield deterioration found in previous nanoparticle-loaded scintillators. As a result, the nanocomposite scintillator exhibited simultaneous improvements in both light yield (visible photons produced per MeV of gamma-photon energy) and gamma attenuation. With these enhancements, a 662 keV Cs-137 gamma photopeak with 9.8% resolution has been detected using a 60 wt % quantum-dot nanocomposite scintillator, demonstrating the potential of such a nanocomposite system in the development of high-performance low-cost spectroscopic gamma detectors.

ICPP: Relativistic Plasma Physics with Ultra-Short High-Intensity Laser Pulses

NASA Astrophysics Data System (ADS)

Meyer-Ter-Vehn, Juergen

2000-10-01

Recent progress in generating ultra-short high-intensity laser pulses has opened a new branch of relativistic plasma physics, which is discussed in this talk in terms of particle-in-cell (PIC) simulations. These pulses create small plasma volumes of high-density plasma with plasma fields above 10^12 V/m and 10^8 Gauss. At intensities beyond 10^18 W/cm^2, now available from table-top systems, they drive relativistic electron currents in self-focussing plasma channels. These currents are close to the Alfven limit and allow to study relativistic current filamentation. A most remarkable feature is the generation of well collimated relativistic electron beams emerging from the channels with energies up to GeV. In dense matter they trigger cascades of gamma-rays, e^+e^- pairs, and a host of nuclear and particle processes. One of the applications may be fast ignition of compressed inertial fusion targets. Above 10^23 W/cm^2, expected to be achieved in the future, solid-density matter becomes relativistically transparent for optical light, and the acceleration of protons to multi-GeV energies is predicted in plasma layers less than 1 mm thick. These results open completely new perspectives for plasma-based accelerator schemes. Three-dimensional PIC simulations turn out to be the superior tool to explore the relativistic plasma kinetics at such intensities. Results obtained with the VLPL code [1] are presented. Different mechanisms of particle acceleration are discussed. Both laser wakefield and direct laser acceleration in plasma channels (by a mechanism similar to inverse free electron lasers) have been identified. The latter describes recent MPQ experimental results. [1] A. Pukhov, J. Plasma Physics 61, 425 - 433 (1999): Three-dimensional electromagnetic relativistic particle-in-cell code VLPL (Virtual Laser Plasma Laboratory).

Low-loss interference filter arrays made by plasma-assisted reactive magnetron sputtering (PARMS) for high-performance multispectral imaging

NASA Astrophysics Data System (ADS)

Broßmann, Jan; Best, Thorsten; Bauer, Thomas; Jakobs, Stefan; Eisenhammer, Thomas

2016-10-01

Optical remote sensing of the earth from air and space typically utilizes several channels in the visible and near infrared spectrum. Thin-film optical interference filters, mostly of narrow bandpass type, are applied to select these channels. The filters are arranged in filter wheels, arrays of discrete stripe filters mounted in frames, or patterned arrays on a monolithic substrate. Such multi-channel filter assemblies can be mounted close to the detector, which allows a compact and lightweight camera design. Recent progress in image resolution and sensor sensitivity requires improvements of the optical filter performance. Higher demands placed on blocking in the UV and NIR and in between the spectral channels, in-band transmission and filter edge steepness as well as scattering lead to more complex filter coatings with thicknesses in the range of 10 - 25μm. Technological limits of the conventionally used ion-assisted evaporation process (IAD) can be overcome only by more precise and higher-energetic coating technologies like plasma-assisted reactive magnetron sputtering (PARMS) in combination with optical broadband monitoring. Optics Balzers has developed a photolithographic patterning process for coating thicknesses up to 15μm that is fully compatible with the advanced PARMS coating technology. This provides the possibility of depositing multiple complex high-performance filters on a monolithic substrate. We present an overview of the performance of recently developed filters with improved spectral performance designed for both monolithic filter-arrays and stripe filters mounted in frames. The pros and cons as well as the resulting limits of the filter designs for both configurations are discussed.

Ultra-thin silicon (UTSi) on insulator CMOS transceiver and time-division multiplexed switch chips for smart pixel integration

NASA Astrophysics Data System (ADS)

Zhang, Liping; Sawchuk, Alexander A.

2001-12-01

We describe the design, fabrication and functionality of two different 0.5 micron CMOS optoelectronic integrated circuit (OEIC) chips based on the Peregrine Semiconductor Ultra-Thin Silicon on insulator technology. The Peregrine UTSi silicon- on-sapphire (SOS) technology is a member of the silicon-on- insulator (SOI) family. The low-loss synthetic sapphire substrate is optically transparent and has good thermal conductivity and coefficient of thermal expansion properties, which meet the requirements for flip-chip bonding of VCSELs and other optoelectronic input-output components. One chip contains transceiver and network components, including four channel high-speed CMOS transceiver modules, pseudo-random bit stream (PRBS) generators, a voltage controlled oscillator (VCO) and other test circuits. The transceiver chips can operate in both self-testing mode and networking mode. An on- chip clock and true-single-phase-clock (TSPC) D-flip-flop have been designed to generate a PRBS at over 2.5 Gb/s for the high-speed transceiver arrays to operate in self-testing mode. In the networking mode, an even number of transceiver chips forms a ring network through free-space or fiber ribbon interconnections. The second chip contains four channel optical time-division multiplex (TDM) switches, optical transceiver arrays, an active pixel detector and additional test devices. The eventual applications of these chips will require monolithic OEICs with integrated optical input and output. After fabrication and testing, the CMOS transceiver array dies will be packaged with 850 nm vertical cavity surface emitting lasers (VCSELs), and metal-semiconductor- metal (MSM) or GaAs p-i-n detector die arrays to achieve high- speed optical interconnections. The hybrid technique could be either wire bonding or flip-chip bonding of the CMOS SOS smart-pixel arrays with arrays of VCSELs and photodetectors onto an optoelectronic chip carrier as a multi-chip module (MCM).

Fabrication of monolithic microfluidic channels in diamond with ion beam lithography

NASA Astrophysics Data System (ADS)

Picollo, F.; Battiato, A.; Boarino, L.; Ditalia Tchernij, S.; Enrico, E.; Forneris, J.; Gilardino, A.; Jakšić, M.; Sardi, F.; Skukan, N.; Tengattini, A.; Olivero, P.; Re, A.; Vittone, E.

2017-08-01

In the present work, we report on the monolithic fabrication by means of ion beam lithography of hollow micro-channels within a diamond substrate, to be employed for microfluidic applications. The fabrication strategy takes advantage of ion beam induced damage to convert diamond into graphite, which is characterized by a higher reactivity to oxidative etching with respect to the chemically inert pristine structure. This phase transition occurs in sub-superficial layers thanks to the peculiar damage profile of MeV ions, which mostly damage the target material at their end of range. The structures were obtained by irradiating commercial CVD diamond samples with a micrometric collimated C+ ion beam at three different energies (4 MeV, 3.5 MeV and 3 MeV) at a total fluence of 2 × 1016 cm-2. The chosen multiple-energy implantation strategy allows to obtain a thick box-like highly damaged region ranging from 1.6 μm to 2.1 μm below the sample surface. High-temperature annealing was performed to both promote the graphitization of the ion-induced amorphous layer and to recover the pristine crystalline structure in the cap layer. Finally, the graphite was removed by ozone etching, obtaining monolithic microfluidic structures. These prototypal microfluidic devices were tested injecting aqueous solutions and the evidence of the passage of fluids through the channels was confirmed by confocal fluorescent microscopy.

Monolithic active pixel radiation detector with shielding techniques

DOEpatents

Deptuch, Grzegorz W.

2018-03-20

A monolithic active pixel radiation detector including a method of fabricating thereof. The disclosed radiation detector can include a substrate comprising a silicon layer upon which electronics are configured. A plurality of channels can be formed on the silicon layer, wherein the plurality of channels are connected to sources of signals located in a bulk part of the substrate, and wherein the signals flow through electrically conducting vias established in an isolation oxide on the substrate. One or more nested wells can be configured from the substrate, wherein the nested wells assist in collecting charge carriers released in interaction with radiation and wherein the nested wells further separate the electronics from the sensing portion of the detector substrate. The detector can also be configured according to a thick SOA method of fabrication.

Monolithic active pixel radiation detector with shielding techniques

DOEpatents

Deptuch, Grzegorz W.

2016-09-06

A monolithic active pixel radiation detector including a method of fabricating thereof. The disclosed radiation detector can include a substrate comprising a silicon layer upon which electronics are configured. A plurality of channels can be formed on the silicon layer, wherein the plurality of channels are connected to sources of signals located in a bulk part of the substrate, and wherein the signals flow through electrically conducting vias established in an isolation oxide on the substrate. One or more nested wells can be configured from the substrate, wherein the nested wells assist in collecting charge carriers released in interaction with radiation and wherein the nested wells further separate the electronics from the sensing portion of the detector substrate. The detector can also be configured according to a thick SOA method of fabrication.

Monolithically integrated distributed feedback laser array wavelength-selectable light sources for WDM-PON application

NASA Astrophysics Data System (ADS)

Chen, Xin; Zhao, Jianyi; Zhou, Ning; Huang, Xiaodong; Cao, Mingde; Wang, Lei; Liu, Wen

2015-01-01

The monolithic integration of 1.5-μm four channels phase shift distributed feedback lasers array (DFB-LD array) with 4×1 multi-mode interference (MMI) optical combiner is demonstrated. A home developed process mainly consists of butt-joint regrowth (BJR) and simultaneous thermal and ultraviolet nanoimprint lithography (STU-NIL) is implemented to fabricate gratings and integrated devices. The threshold currents of the lasers are less than 10 mA and the side mode suppression ratios (SMSR) are better than 40 dB for all channels. Quasi-continuous tuning is realized over 7.5 nm wavelength region with the 30 °C temperature variation. The results indicate that the integration device we proposed can be used in wavelength division multiplexing passive optical networks (WDM-PON).

The Aerogel Mesh Contamination Collector

DTIC Science & Technology

1993-07-01

patent pending 2.1 Introduction The new method of contamination prevention and collection described herein employs ultra-low density silica aerogel and a... silica aerogel and the Section 2.2 presents the fabrication of the acrogel me:sh contamination collector (AMCC). The device is a heterostructure...monolithic photonic devices and lightweight optics). This report series will focus on silica aerogels almost exclusively. It is also of interest to note that

76 FR 52037 - Self-Regulatory Organizations; NYSE Arca, Inc.; Order Approving a Proposed Rule Change To List...

Federal Register 2010, 2011, 2012, 2013, 2014

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... the Following Under NYSE Arca Equities Rule 8.200: ProShares Short DJ-UBS Natural Gas, ProShares Ultra DJ-UBS Natural Gas and ProShares UltraShort DJ-UBS Natural Gas August 15, 2011. I. Introduction On... DJ-UBS Natural Gas, ProShares Ultra DJ-UBS Natural Gas, and ProShares UltraShort DJ-UBS Natural Gas...

Ultra-short ion and neutron pulse production

DOEpatents

Leung, Ka-Ngo; Barletta, William A.; Kwan, Joe W.

2006-01-10

An ion source has an extraction system configured to produce ultra-short ion pulses, i.e. pulses with pulse width of about 1 .mu.s or less, and a neutron source based on the ion source produces correspondingly ultra-short neutron pulses. To form a neutron source, a neutron generating target is positioned to receive an accelerated extracted ion beam from the ion source. To produce the ultra-short ion or neutron pulses, the apertures in the extraction system of the ion source are suitably sized to prevent ion leakage, the electrodes are suitably spaced, and the extraction voltage is controlled. The ion beam current leaving the source is regulated by applying ultra-short voltage pulses of a suitable voltage on the extraction electrode.

High density, optically corrected, micro-channel cooled, v-groove monolithic laser diode array

DOEpatents

Freitas, Barry L.

1998-01-01

An optically corrected, micro-channel cooled, high density laser diode array achieves stacking pitches to 33 bars/cm by mounting laser diodes into V-shaped grooves. This design will deliver>4kW/cm2 of directional pulsed laser power. This optically corrected, micro-channel cooled, high density laser is usable in all solid state laser systems which require efficient, directional, narrow bandwidth, high optical power density pump sources.

Rectenna Technology Program: Ultra light 2.45 GHz rectenna 20 GHz rectenna

NASA Technical Reports Server (NTRS)

Brown, William C.

1987-01-01

The program had two general objectives. The first objective was to develop the two plane rectenna format for space application at 2.45 GHz. The resultant foreplane was a thin-film, etched-circuit format fabricated from a laminate composed of 2 mil Kapton F sandwiched between sheets of 1 oz copper. The thin-film foreplane contains half wave dipoles, filter circuits, rectifying Schottky diode, and dc bussing lead. It weighs 160 grams per square meter. Efficiency and dc power output density were measured at 85% and 1 kw/sq m, respectively. Special testing techniques to measure temperature of circuit and diode without perturbing microwave operation using the fluoroptic thermometer were developed. A second objective was to investigate rectenna technology for use at 20 GHz and higher frequencies. Several fabrication formats including the thin-film scaled from 2.45 GHz, ceramic substrate and silk-screening, and monolithic were investigated, with the conclusion that the monolithic approach was the best. A preliminary design of the monolithic rectenna structure and the integrated Schottky diode were made.

Monolithic Microfluidic Mixing-Spraying Devices for Time-Resolved Cryo-Electron Microscopy

PubMed Central

Lu, Zonghuan; Shaikh, Tanvir R.; Barnard, David; Meng, Xing; Mohamed, Hisham; Yassin, Aymen; Mannella, Carmen A.; Agrawal, Rajendra K.; Lu, Toh-Ming

2009-01-01

The goal of time-resolved cryo-electron microscopy is to determine structural models for transient functional states of large macromolecular complexes such as ribosomes and viruses. The challenge of time-resolved cryo-electron microscopy is to rapidly mix reactants, and then, following a defined time interval, to rapidly deposit them as a thin film and freeze the sample to the vitreous state. Here we describe a methodology in which reaction components are mixed and allowed to react, and are then sprayed onto an EM grid as it is being plunged into cryogen. All steps are accomplished by a monolithic, microfabricated silicon device that incorporates a mixer, reaction channel, and pneumatic sprayer in a single chip. We have found that microdroplets produced by air atomization spread to sufficiently thin films on a millisecond time scale provided that the carbon supporting film is made suitably hydrophilic. The device incorporates two T-mixers flowing into a single channel of four butterfly-shaped mixing elements that ensure effective mixing, followed by a microfluidic reaction channel whose length can be varied to achieve the desired reaction time. The reaction channel is flanked by two ports connected to compressed humidified nitrogen gas (at 50 psi) to generate the spray. The monolithic mixer-sprayer is incorporated into a computer-controlled plunging apparatus. To test the mixing performance and the suitability of the device for preparation of biological macromolecules for cryo-EM, ribosomes and ferritin were mixed in the device and sprayed onto grids. Three-dimensional reconstructions of the ribosomes demonstrated retention of native structure, and 30S and 50S subunits were shown to be capable of reassociation into ribosomes after passage through the device. PMID:19683579

75 FR 22889 - Self-Regulatory Organizations; International Securities Exchange, LLC; Notice of Filing and...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-30

... transactions. Currently, the First Trust ISE Water ETF (``FIW''), the Claymore China Technology ETF (``CQQQ''), the ProShares UltraPro Short Dow30 (``SDOW''), the ProShares UltraPro Dow30 (``UDOW''), the ProShares UltraPro Short MidCap400 (``SMDD''), the ProShares UltraPro MidCap400 (``UMDD''), the ProShares UltraPro...

High density, optically corrected, micro-channel cooled, v-groove monolithic laser diode array

DOEpatents

Freitas, B.L.

1998-10-27

An optically corrected, micro-channel cooled, high density laser diode array achieves stacking pitches to 33 bars/cm by mounting laser diodes into V-shaped grooves. This design will deliver > 4kW/cm{sup 2} of directional pulsed laser power. This optically corrected, micro-channel cooled, high density laser is usable in all solid state laser systems which require efficient, directional, narrow bandwidth, high optical power density pump sources. 13 figs.

Ultra-Thin, Triple-Bandgap GaInP/GaAs/GaInAs Monolithic Tandem Solar Cells

NASA Technical Reports Server (NTRS)

Wanlass, M. W.; Ahrenkiel, S. P.; Albin, D. S.; Carapella, J. J.; Duda, A.; Emery, K.; Geisz, J. F.; Jones, K.; Kurtz, Sarah; Moriarty, T.;

Water and Solute Mass Transport in Soils Developed on glacial Drift: A Br Tracer Investigation Using Instrumented Soil Monoliths at an Agricultural Long Term Ecological Research Site (Kellogg Biological Station, Hickory Corners, Southern Michigan)

NASA Astrophysics Data System (ADS)

Jin, L.; Hamilton, S. K.; Walter, L. M.

2004-12-01

Hydrologic processes control the residence time of water in the soil column. This is of central importance in understanding mineral weathering rates in terms of reaction kinetics and solute transport. In order to better quantify the coupling between water and solute mass transport and to better define controls on carbonate and aluminosilicates weathering rates, we have conducted bromide-tracer introduction experiments at four replicate soil monoliths (4 m3 volume) instrumented and managed by the KBS-LTER. Monolith soils are developed on the pitted outwash plain of the morainic system left by the last retreat of the Wisconsin glaciation, around 12,000 years ago. Soil profiles from the monolith sections extend to 200 cm and they were sampled and characterized texturally and mineralogically. Quartz and feldspar are dominant throughout the soil profile, while carbonates and hornblende occur only in deeper soil horizons. The four replicate monoliths are instrumented with gas and soil water sampling devices (Prenart tension lysimeters) at various depths. The monoliths also have a large capacity tray at the bottom, which permits collection of water for weight and chemical determinations. A bromide tracer solution (as lithium bromide) was applied to coincide as closely as possible with a major snowmelt event (2/27/04). The saturated and unsaturated transport of bromide through the four monoliths was followed as a function of time and soil profile depth for the duration of the snowmelt as well as intermittent rain events. Because the soil was saturated at the time of bromide application, the bromide solution is expected to move rapidly through macropores, followed by slower movement into micropores. The unsaturated transport of bromide is largely controlled by the intensity and duration of the rains if it is dominated by piston flow as opposed to preferential channel flow. In general, the tracer moved through the shallow soils very quickly, which is shown by early sharp peaks in bromide concentrations. Transport of bromide into deeper soil horizons, however, differs markedly among the four monoliths. Even within a given monolith, waters sampled at the same depth by different tension lysimeters show a very different pattern of bromide transport over time with some lyimeters suggesting piston flow, while others in the same monolith suggest preferential channel flow. These differences are likely driven by heterogeneous soil textures. The water recovered from the monolith trays over the first three months of the study period is between 80 and 90 percent of the total precipitation recorded at the LTER site. This recovery is reasonable given the fact that temperature was low and crops were not yet actively growing. The recovery of bromide is different among the monoliths and in general is less than 50 percent, which means more than 50 percent of tracer is still in the soils even after three months. Residence time of water has been calculated after some assumptions on the breakthrough curve. The water mass transport constraints imposed by the bromide tracer study will be utilized in concert with additional data on soil water geochemistry.

Monolithic Parallel Tandem Organic Photovoltaic Cell with Transparent Carbon Nanotube Interlayer

NASA Technical Reports Server (NTRS)

Tanaka, S.; Mielczarek, K.; Ovalle-Robles, R.; Wang, B.; Hsu, D.; Zakhidov, A. A.

2009-01-01

We demonstrate an organic photovoltaic cell with a monolithic tandem structure in parallel connection. Transparent multiwalled carbon nanotube sheets are used as an interlayer anode electrode for this parallel tandem. The characteristics of front and back cells are measured independently. The short circuit current density of the parallel tandem cell is larger than the currents of each individual cell. The wavelength dependence of photocurrent for the parallel tandem cell shows the superposition spectrum of the two spectral sensitivities of the front and back cells. The monolithic three-electrode photovoltaic cell indeed operates as a parallel tandem with improved efficiency.

Metal oxide nanorod arrays on monolithic substrates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, Pu-Xian; Guo, Yanbing; Ren, Zheng

A metal oxide nanorod array structure according to embodiments disclosed herein includes a monolithic substrate having a surface and multiple channels, an interface layer bonded to the surface of the substrate, and a metal oxide nanorod array coupled to the substrate surface via the interface layer. The metal oxide can include ceria, zinc oxide, tin oxide, alumina, zirconia, cobalt oxide, and gallium oxide. The substrate can include a glass substrate, a plastic substrate, a silicon substrate, a ceramic monolith, and a stainless steel monolith. The ceramic can include cordierite, alumina, tin oxide, and titania. The nanorod array structure can includemore » a perovskite shell, such as a lanthanum-based transition metal oxide, or a metal oxide shell, such as ceria, zinc oxide, tin oxide, alumina, zirconia, cobalt oxide, and gallium oxide, or a coating of metal particles, such as platinum, gold, palladium, rhodium, and ruthenium, over each metal oxide nanorod. Structures can be bonded to the surface of a substrate and resist erosion if exposed to high velocity flow rates.« less

Introduction of a breast cancer care programme including ultra short hospital stay in 4 early adopter centres: framework for an implementation study.

PubMed

de Kok, Mascha; Frotscher, Caroline N A; van der Weijden, Trudy; Kessels, Alfons G H; Dirksen, Carmen D; van de Velde, Cornelis J H; Roukema, Jan A; Bell, Antoine V R J; van der Ent, Fred W; von Meyenfeldt, Maarten F

2007-07-02

Whereas ultra-short stay (day care or 24 hour hospitalisation) following breast cancer surgery was introduced in the US and Canada in the 1990s, it is not yet common practice in Europe. This paper describes the design of the MaDO study, which involves the implementation of ultra short stay admission for patients after breast cancer surgery, and evaluates whether the targets of the implementation strategy are reached. The ultra short stay programme and the applied implementation strategy will be evaluated from the economic perspective. The MaDO study is a pre-post-controlled multi-centre study, that is performed in four hospitals in the Netherlands. It includes a pre and post measuring period of six months each with six months of implementation in between in at least 40 patients per hospital per measurement period. Primary outcome measure is the percentage of patients treated in ultra short stay. Secondary endpoints are the percentage of patients treated according to protocol, degree of involvement of home care nursing, quality of care from the patient's perspective, cost-effectiveness of the ultra short stay programme and cost-effectiveness of the implementation strategy. Quality of care will be measured by the QUOTE-breast cancer instrument, cost-effectiveness of the ultra short stay programme will be measured by means of the EuroQol (administered at four time-points) and a cost book for patients. Cost-effectiveness analysis will be performed from a societal perspective. Cost-effectiveness of the implementation strategy will be measured by determination of the costs of implementation activities. This study will reveal barriers and facilitators for implementation of the ultra short stay programme. Moreover, the results of the study will provide information about the cost-effectiveness of the ultra short stay programme and the implementation strategy. Current Controlled Trials ISRCTN77253391.

The interaction of intense, ultra-short microwave beams with the plasma generated by gas ionization

NASA Astrophysics Data System (ADS)

Shafir, G.; Cao, Y.; Bliokh, Y.; Leopold, J. G.; Levko, D.; Rostov, V.; Gad, R.; Fisher, A.; Bernshtam, V.; Krasik, Ya. E.

2018-03-01

Results of the non-linear interaction of an extremely short (0.6 ns) high power (˜500 MW) X-band focused microwave beam with the plasma generated by gas ionization are presented. Within certain gas pressure ranges, specific to the gas type, the plasma density is considerably lower around the microwave beam axis than at its periphery, thus forming guiding channel through which the beam self-focuses. Outside these pressure ranges, either diffuse or streamer-like plasma is observed. We also observe high energy electrons (˜15 keV), accelerated by the very high-power microwaves. A simplified analytical model of this complicated dynamical system and particle-in-cell numerical simulations confirm the experimental results.

Multiple-Event, Single-Photon Counting Imaging Sensor

NASA Technical Reports Server (NTRS)

Zheng, Xinyu; Cunningham, Thomas J.; Sun, Chao; Wang, Kang L.

2011-01-01

The single-photon counting imaging sensor is typically an array of silicon Geiger-mode avalanche photodiodes that are monolithically integrated with CMOS (complementary metal oxide semiconductor) readout, signal processing, and addressing circuits located in each pixel and the peripheral area of the chip. The major problem is its single-event method for photon count number registration. A single-event single-photon counting imaging array only allows registration of up to one photon count in each of its pixels during a frame time, i.e., the interval between two successive pixel reset operations. Since the frame time can t be too short, this will lead to very low dynamic range and make the sensor merely useful for very low flux environments. The second problem of the prior technique is a limited fill factor resulting from consumption of chip area by the monolithically integrated CMOS readout in pixels. The resulting low photon collection efficiency will substantially ruin any benefit gained from the very sensitive single-photon counting detection. The single-photon counting imaging sensor developed in this work has a novel multiple-event architecture, which allows each of its pixels to register as more than one million (or more) photon-counting events during a frame time. Because of a consequently boosted dynamic range, the imaging array of the invention is capable of performing single-photon counting under ultra-low light through high-flux environments. On the other hand, since the multiple-event architecture is implemented in a hybrid structure, back-illumination and close-to-unity fill factor can be realized, and maximized quantum efficiency can also be achieved in the detector array.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lecomte, Roger; Arpin, Louis; Beaudoin, Jean-Franç

Purpose: LabPET II is a new generation APD-based PET scanner designed to achieve sub-mm spatial resolution using truly pixelated detectors and highly integrated parallel front-end processing electronics. Methods: The basic element uses a 4×8 array of 1.12×1.12 mm{sup 2} Lu{sub 1.9}Y{sub 0.1}SiO{sub 5}:Ce (LYSO) scintillator pixels with one-to-one coupling to a 4×8 pixelated monolithic APD array mounted on a ceramic carrier. Four detector arrays are mounted on a daughter board carrying two flip-chip, 64-channel, mixed-signal, application-specific integrated circuits (ASIC) on the backside interfacing to two detector arrays each. Fully parallel signal processing was implemented in silico by encoding time andmore » energy information using a dual-threshold Time-over-Threshold (ToT) scheme. The self-contained 128-channel detector module was designed as a generic component for ultra-high resolution PET imaging of small to medium-size animals. Results: Energy and timing performance were optimized by carefully setting ToT thresholds to minimize the noise/slope ratio. ToT spectra clearly show resolved 511 keV photopeak and Compton edge with ToT resolution well below 10%. After correction for nonlinear ToT response, energy resolution is typically 24±2% FWHM. Coincidence time resolution between opposing 128-channel modules is below 4 ns FWHM. Initial imaging results demonstrate that 0.8 mm hot spots of a Derenzo phantom can be resolved. Conclusion: A new generation PET scanner featuring truly pixelated detectors was developed and shown to achieve a spatial resolution approaching the physical limit of PET. Future plans are to integrate a small-bore dedicated mouse version of the scanner within a PET/CT platform.« less

Large current MOSFET on photonic silicon-on-insulator wafers and its monolithic integration with a thermo-optic 2 × 2 Mach-Zehnder switch.

PubMed

Cong, G W; Matsukawa, T; Chiba, T; Tadokoro, H; Yanagihara, M; Ohno, M; Kawashima, H; Kuwatsuka, H; Igarashi, Y; Masahara, M; Ishikawa, H

2013-03-25

n-channel body-tied partially depleted metal-oxide-semiconductor field-effect transistors (MOSFETs) were fabricated for large current applications on a silicon-on-insulator wafer with photonics-oriented specifications. The MOSFET can drive an electrical current as large as 20 mA. We monolithically integrated this MOSFET with a 2 × 2 Mach-Zehnder interferometer optical switch having thermo-optic phase shifters. The static and dynamic performances of the integrated device are experimentally evaluated.

Mechanical design of a single-axis monolithic accelerometer for advanced seismic attenuation systems

NASA Astrophysics Data System (ADS)

Bertolini, Alessandro; DeSalvo, Riccardo; Fidecaro, Francesco; Francesconi, Mario; Marka, Szabolcs; Sannibale, Virginio; Simonetti, Duccio; Takamori, Akiteru; Tariq, Hareem

2006-01-01

The design and mechanics for a new very-low noise low frequency horizontal accelerometer is presented. The sensor has been designed to be integrated in an advanced seismic isolation system for interferometric gravitational wave detectors. The motion of a small monolithic folded-pendulum (FP) is monitored by a high resolution capacitance displacement sensor; a feedback force actuator keeps the mass at the equilibrium position. The feedback signal is proportional to the ground acceleration in the frequency range 0-150 Hz. The very high mechanical quality factor, Q≃3000 at a resonant frequency of 0.5 Hz, reduces the Brownian motion of the proof mass of the accelerometer below the resolution of the displacement sensor. This scheme enables the accelerometer to detect the inertial displacement of a platform with a root-mean-square noise less than 1 nm, integrated over the frequency band from 0.01 to 150 Hz. The FP geometry, combined with the monolithic design, allows the accelerometer to be extremely directional. A vertical-horizontal coupling ranging better than 10-3 has been achieved. A detailed account of the design and construction of the accelerometer is reported here. The instrument is fully ultra-high vacuum compatible and has been tested and approved for integration in seismic attenuation system of japanese TAMA 300 gravitational wave detector. The monolithic design also makes the accelerometer suitable for cryogenic operation.

Hydrogel coated monoliths for enzymatic hydrolysis of penicillin G

PubMed Central

Smeltink, M. W.; Straathof, A. J. J.; Paasman, M. A.; van de Sandt, E. J. A. X.; Kapteijn, F.; Moulijn, J. A.

2008-01-01

The objective of this work was to develop a hydrogel-coated monolith for the entrapment of penicillin G acylase (E. coli, PGA). After screening of different hydrogels, chitosan was chosen as the carrier material for the preparation of monolithic biocatalysts. This protocol leads to active immobilized biocatalysts for the enzymatic hydrolysis of penicillin G (PenG). The monolithic biocatalyst was tested in a monolith loop reactor (MLR) and compared with conventional reactor systems using free PGA, and a commercially available immobilized PGA. The optimal immobilization protocol was found to be 5 g l−1 PGA, 1% chitosan, 1.1% glutaraldehyde and pH 7. Final PGA loading on glass plates was 29 mg ml−1 gel. For 400 cpsi monoliths, the final PGA loading on functionalized monoliths was 36 mg ml−1 gel. The observed volumetric reaction rate in the MLR was 0.79 mol s−1 m−3monolith. Apart from an initial drop in activity due to wash out of PGA at higher ionic strength, no decrease in activity was observed after five subsequent activity test runs. The storage stability of the biocatalysts is at least a month without loss of activity. Although the monolithic biocatalyst as used in the MLR is still outperformed by the current industrial catalyst (immobilized preparation of PGA, 4.5 mol s−1 m−3catalyst), the rate per gel volume is slightly higher for monolithic catalysts. Good activity and improved mechanical strength make the monolithic bioreactor an interesting alternative that deserves further investigation for this application. Although moderate internal diffusion limitations have been observed inside the gel beads and in the gel layer on the monolith channel, this is not the main reason for the large differences in reactor performance that were observed. The pH drop over the reactor as a result of the chosen method for pH control results in a decreased performance of both the MLR and the packed bed reactor compared to the batch system. A different reactor configuration including an optimal pH profile is required to increase the reactor performance. The monolithic stirrer reactor would be an interesting alternative to improve the performance of the monolith-PGA combination. PMID:18427849

Monolithic, multi-bandgap, tandem, ultra-thin, strain-counterbalanced, photovoltaic energy converters with optimal subcell bandgaps

DOEpatents

Wanlass, Mark W [Golden, CO; Mascarenhas, Angelo [Lakewood, CO

2012-05-08

Modeling a monolithic, multi-bandgap, tandem, solar photovoltaic converter or thermophotovoltaic converter by constraining the bandgap value for the bottom subcell to no less than a particular value produces an optimum combination of subcell bandgaps that provide theoretical energy conversion efficiencies nearly as good as unconstrained maximum theoretical conversion efficiency models, but which are more conducive to actual fabrication to achieve such conversion efficiencies than unconstrained model optimum bandgap combinations. Achieving such constrained or unconstrained optimum bandgap combinations includes growth of a graded layer transition from larger lattice constant on the parent substrate to a smaller lattice constant to accommodate higher bandgap upper subcells and at least one graded layer that transitions back to a larger lattice constant to accommodate lower bandgap lower subcells and to counter-strain the epistructure to mitigate epistructure bowing.

Monolithic diffraction-limited 976-nm laser based on saddle-shaped photo darkening-free Yb-doped fiber

NASA Astrophysics Data System (ADS)

Aleshkina, Svetlana S.; Lipatov, Denis S.; Levchenko, Andrei E.; Medvedkov, Oleg I.; Bobkov, Konstantin K.; Bubnov, Mikhail M.; Guryanov, Alexei N.; Likhachev, Mikhail E.

2018-02-01

Monolithic 976 nm laser design based on a newly developed saddle-shaped Yb-doped fiber has been proposed. The fiber has central single-mode part with core diameter of about 12 μm and ultra-thin square-shaped clad with side of about 42x42 μm. At the both ends of the saddle-shaped fiber the core and the clad sizes were adiabatically increased up to 20/(70x70) μm and the fiber could be spliced with standard (80..125 μm clad) passive fibers using commercially available equipment. Single-mode laser at 976 nm based on the developed fiber has been fabricated and photodarkening-free operation with output power of 10.6 W, which is the record high for all-fiber laser schemes, has been demonstrated.

UltraNet Target Parameters. Chapter 1

NASA Technical Reports Server (NTRS)

Kislitzin, Katherine T.; Blaylock, Bruce T. (Technical Monitor)

1992-01-01

The UltraNet is a high speed network capable of rates up to one gigabit per second. It is a hub based network with four optical fiber links connecting each hub. Each link can carry up to 256 megabits of data, and the hub backplane is capable of one gigabit aggregate throughput. Host connections to the hub may be fiber, coax, or channel based. Bus based machines have adapter boards that connect to transceivers in the hub, while channel based machines use a personality module in the hub. One way that the UltraNet achieves its high transfer rates is by off-loading the protocol processing from the hosts to special purpose protocol engines in the UltraNet hubs. In addition, every hub has a PC connected to it by StarLAN for network management purposes. Although there is hub resident and PC resident UltraNet software, this document treats only the host resident UltraNet software.

Compact high-pulse-energy passively Q-switched Nd:YLF laser with an ultra-low-magnification unstable resonator: application for efficient optical parametric oscillator.

PubMed

Cho, C Y; Huang, Y P; Huang, Y J; Chen, Y C; Su, K W; Chen, Y F

2013-01-28

We exploit an ultra-low-magnification unstable resonator to develop a high-pulse-energy side-pumped passively Q-switched Nd:YLF/Cr⁴⁺:YAG laser with improving beam quality. A wedged laser crystal is employed in the cavity to control the emissions at 1047 nm and 1053 nm independently through the cavity alignment. The pulse energies at 1047 nm and 1053 nm are found to be 19 mJ and 23 mJ, respectively. The peak powers for both wavelengths are higher than 2 MW. Furthermore, the developed Nd:YLF lasers are employed to pump a monolithic optical parametric oscillator for confirming the applicability in nonlinear wavelength conversions.

Dopamine-imprinted monolithic column for capillary electrochromatography.

PubMed

Aşır, Süleyman; Sarı, Duygu; Derazshamshir, Ali; Yılmaz, Fatma; Şarkaya, Koray; Denizli, Adil

2017-11-01

A dopamine-imprinted monolithic column was prepared and used in capillary electrochromatography as stationary phase for the first time. Dopamine was selectively separated from aqueous solution containing the competitor molecule norepinephrine, which is similar in size and shape to the template molecule. Morphology of the dopamine-imprinted column was observed by scanning electron microscopy. The influence of the organic solvent content of mobile phase, applied pressure and pH of the mobile phase on the recognition of dopamine by the imprinted monolithic column has been evaluated, and the imprinting effect in the dopamine-imprinted monolithic polymer was verified. Developed dopamine-imprinted monolithic column resulted in excellent separation of dopamine from structurally related competitor molecule, norepinephrine. Separation was achieved in a short period of 10 min, with the electrophoretic mobility of 5.81 × 10 -5  m 2 V -1 s -1 at pH 5.0 and 500 mbar pressure. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Compact & Ultra-High Resolution Terahertz Spectroscopic/Fingerprint System

DTIC Science & Technology

2011-05-11

successfully fusion - spliced with commercial silica fibers for the first time, which makes the whole MOPA system monolithic. Fig. 7 (a) shows the output...QPM-GaP crystals and the proposed THz crystal fiber converters for high power parametric THz source, THz waveguide modeling for high efficiency and...THz spectroscopic/fingerprinting system. We have achieved 0.212 mJ fiber laser pulses with transform-limited linewidth, bonded QPM-GaP crystals and

Multi-channel polarized thermal emitter

DOEpatents

Lee, Jae-Hwang; Ho, Kai-Ming; Constant, Kristen P

2013-07-16

A multi-channel polarized thermal emitter (PTE) is presented. The multi-channel PTE can emit polarized thermal radiation without using a polarizer at normal emergence. The multi-channel PTE consists of two layers of metallic gratings on a monolithic and homogeneous metallic plate. It can be fabricated by a low-cost soft lithography technique called two-polymer microtransfer molding. The spectral positions of the mid-infrared (MIR) radiation peaks can be tuned by changing the periodicity of the gratings and the spectral separation between peaks are tuned by changing the mutual angle between the orientations of the two gratings.

75 FR 14236 - Self-Regulatory Organizations; International Securities Exchange, LLC; Notice of Filing and...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-24

... transactions. Currently, the First Trust ISE Water ETF (``FIW'') and the Claymore China Technology ETF (``CQQQ... options on the ProShares UltraPro Short Dow30 (``SDOW''), the ProShares UltraPro Dow30 (``UDOW''), the ProShares UltraPro Short MidCap400 (``SMDD''), the ProShares UltraPro MidCap400 (``UMDD''), the ProShares...

Validation and perspectives of a femtosecond laser fabricated monolithic optical stretcher

PubMed Central

Bellini, Nicola; Bragheri, Francesca; Cristiani, Ilaria; Guck, Jochen; Osellame, Roberto; Whyte, Graeme

2012-01-01

The combination of high power laser beams with microfluidic delivery of cells is at the heart of high-throughput, single-cell analysis and disease diagnosis with an optical stretcher. So far, the challenges arising from this combination have been addressed by externally aligning optical fibres with microfluidic glass capillaries, which has a limited potential for integration into lab-on-a-chip environments. Here we demonstrate the successful production and use of a monolithic glass chip for optical stretching of white blood cells, featuring microfluidic channels and optical waveguides directly written into bulk glass by femtosecond laser pulses. The performance of this novel chip is compared to the standard capillary configuration. The robustness, durability and potential for intricate flow patterns provided by this monolithic optical stretcher chip suggest its use for future diagnostic and biotechnological applications. PMID:23082304

Nanoscale MOS devices: device parameter fluctuations and low-frequency noise (Invited Paper)

NASA Astrophysics Data System (ADS)

Wong, Hei; Iwai, Hiroshi; Liou, J. J.

2005-05-01

It is well-known in conventional MOS transistors that the low-frequency noise or flicker noise is mainly contributed by the trapping-detrapping events in the gate oxide and the mobility fluctuation in the surface channel. In nanoscale MOS transistors, the number of trapping-detrapping events becomes less important because of the large direct tunneling current through the ultrathin gate dielectric which reduces the probability of trapping-detrapping and the level of leakage current fluctuation. Other noise sources become more significant in nanoscale devices. The source and drain resistance noises have greater impact on the drain current noise. Significant contribution of the parasitic bipolar transistor noise in ultra-short channel and channel mobility fluctuation to the channel noise are observed. The channel mobility fluctuation in nanoscale devices could be due to the local composition fluctuation of the gate dielectric material which gives rise to the permittivity fluctuation along the channel and results in gigantic channel potential fluctuation. On the other hand, the statistical variations of the device parameters across the wafer would cause the noise measurements less accurate which will be a challenge for the applicability of analytical flicker noise model as a process or device evaluation tool for nanoscale devices. Some measures for circumventing these difficulties are proposed.

Monolithically Integrated Flexible Black Phosphorus Complementary Inverter Circuits.

PubMed

Liu, Yuanda; Ang, Kah-Wee

2017-07-25

Two-dimensional (2D) inverters are a fundamental building block for flexible logic circuits which have previously been realized by heterogeneously wiring transistors with two discrete channel materials. Here, we demonstrate a monolithically integrated complementary inverter made using a homogeneous black phosphorus (BP) nanosheet on flexible substrates. The digital logic inverter circuit is demonstrated via effective threshold voltage tuning within a single BP material, which offers both electron and hole dominated conducting channels with nearly symmetric pinch-off and current saturation. Controllable electron concentration is achieved by accurately modulating the aluminum (Al) donor doping, which realizes BP n-FET with a room-temperature on/off ratio >10 3 . Simultaneously, work function engineering is employed to obtain a low Schottky barrier contact electrode that facilities hole injection, thus enhancing the current density of the BP p-FET by 9.4 times. The flexible inverter circuit shows a clear digital logic voltage inversion operation along with a larger-than-unity direct current voltage gain, while exhibits alternating current dynamic signal switching at a record high frequency up to 100 kHz and remarkable electrical stability upon mechanical bending with a radii as small as 4 mm. Our study demonstrates a practical monolithic integration strategy for achieving functional logic circuits on one material platform, paving the way for future high-density flexible electronic applications.

Electrochromatography on acrylate-based monolith in cyclic olefin copolymer microchip: a cost-effective and easy-to-use technology.

PubMed

Ladner, Yoann; Crétier, Gérard; Faure, Karine

2012-10-01

This article shows that there is great interest in using an electrochromatographic microchip made of hexyl acrylate (HA) based porous monolith cast within the channel of a cyclic olefin copolymer (COC) device. The monolith is simultaneously in situ synthesized and anchored to the inner walls of the channel in less than 10 min. By appropriate choice of light intensity used during the synthesis, the separation efficiency obtained for nonpolar solutes such as polycyclic aromatic hydrocarbons (PAH) is increased up to 250 000 plates/m. The performance of this HA-filled COC microchip was investigated for a wide range of analytes of varying nature. The reversed-phase separation of four aflatoxins is obtained in less than 2 min. The baseline separation of a mixture of neurotransmitters including six amino acids and two catecholamines is possible thanks to the superimposition of the differences in electrophoretic mobility on the chromatographic process. The durability of the system at pH 13 allows the separation of five biogenic amines and the quantitative determination of two of them in numerous wine samples. The feasibility of on-line preconcentration is also demonstrated. Hydrophilic surface modification of COC channel via UV-photografting with poly(ethylene glycol) methacrylate (PEGMA) before in situ synthesis of HA, is necessary to reduce the adsorption of very hydrophobic solutes such as PAH during enrichment. The detection limit of fluoranthene is decreased down to less than 1 ppb with a preconcentration of 4.5 h on the HA-filled PEGMA functionalized COC microchip. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Capillary electrochromatography immunoassay for alpha-fetoprotein based on poly(guanidinium ionic liquid) monolithic material.

PubMed

Liu, Cuicui; Deng, Qiliang; Fang, Guozhen; Dang, Meng; Wang, Shuo

2017-08-01

Alpha-fetoprotein (AFP) is widely used as a tumor marker for the serum diagnosis of primary hepatoma. Sensitive detection of AFP level plays an important role in the early diagnosis of disease and highly reliable prediction. In this study, a novel non-competitive immunoassay (IA) based on poly(guanidinium ionic liquid) monolithic material was developed for detecting ultra trace levels of AFP in capillary electrochromatography (CEC) mode. The AFP was mixed with an excess amount of fluorescently labeled antibody. After incubation, the immunocomplex was separated from the free labeled antibody and detected by CEC coupled with laser-induced fluorescence detector. Under the optimized conditions, the developed CEC-IA performed a low detection limit of 0.05 μg L -1  (S/N = 3) and a wide linearity ranging from 0.1 to 1000 μg L -1 for AFP, which can be largely attributed to the high separation and enrichment efficiency of poly(guanidinium ionic liquid) monolithic material for the targets. The application of this method was demonstrated by determining AFP in human serum. Copyright © 2017. Published by Elsevier Inc.

Computer aided design of monolithic microwave and millimeter wave integrated circuits and subsystems

NASA Astrophysics Data System (ADS)

Ku, Walter H.

1987-08-01

This interim technical report presents results of research on the computer aided design of monolithic microwave and millimeter wave integrated circuits and subsystems. A specific objective is to extend the state-of-the-art of the Computer Aided Design (CAD) of the monolithic microwave and millimeter wave integrated circuits (MIMIC). In this reporting period, we have derived a new model for the high electron mobility transistor (HEMT) based on a nonlinear charge control formulation which takes into consideration the variation of the 2DEG distance offset from the heterointerface as a function of bias. Pseudomorphic InGaAs/GaAs HEMT devices have been successfully fabricated at UCSD. For a 1 micron gate length, a maximum transconductance of 320 mS/mm was obtained. In cooperation with TRW, devices with 0.15 micron and 0.25 micron gate lengths have been successfully fabricated and tested. New results on the design of ultra-wideband distributed amplifiers using 0.15 micron pseudomorphic InGaAs/GaAs HEMT's have also been obtained. In addition, two-dimensional models of the submicron MESFET's, HEMT's and HBT's are currently being developed for the CRAY X-MP/48 supercomputer. Preliminary results obtained are also presented in this report.

Ultrafast UPLC-ESI-MS and HPLC with monolithic column for determination of principal flavor compounds in vanilla pods.

PubMed

Sharma, Upendra K; Sharma, Nandini; Sinha, Arun K; Kumar, Neeraj; Gupta, Ajai P

2009-10-01

In this study, two novel chromatographic methods based on monolithic column high-performance liquid chromatography (HPLC) and ultra-performance liquid chromatography (UPLC) were developed for the ultrafast determination of principal flavor compounds namely vanillin, vanillic acid, p-hydroxybenzoic acid, and p-hydroxybenzaldehyde in ethanolic extracts of Vanilla planifolia pods. Good separation was achieved within 2.5 min using Chromolith RP18e column (100 mm x 4.6 mm) for HPLC and Acquity BEH C-18 (100 mm x 2.1 mm, 1.7 microm) column for UPLC. Both methods were compared in terms of total analysis time, mobile phase consumption, sensitivity, and validation parameters like precision, accuracy, LOD, and LOQ. Further, system suitability test data including resolution, capacity factor, theoretical plates, and tailing factor was determined for both the methods by ten replicate injections. Monolithic column based HPLC gave better results for most of the selected parameters while UPLC was found to be more eco-friendly with low mobile phase consumption and better sensitivity. Both methods may be used conveniently for the high throughput analysis of large number of samples in comparison to traditional particulate column.

Monolithic integration of a silica AWG and Ge photodiodes on Si photonic platform for one-chip WDM receiver.

PubMed

Nishi, Hidetaka; Tsuchizawa, Tai; Kou, Rai; Shinojima, Hiroyuki; Yamada, Takashi; Kimura, Hideaki; Ishikawa, Yasuhiko; Wada, Kazumi; Yamada, Koji

2012-04-09

On the silicon (Si) photonic platform, we monolithically integrated a silica-based arrayed-waveguide grating (AWG) and germanium (Ge) photodiodes (PDs) using low-temperature fabrication technology. We confirmed demultiplexing by the AWG, optical-electrical signal conversion by Ge PDs, and high-speed signal detection at all channels. In addition, we mounted a multichannel transimpedance amplifier/limiting amplifier (TIA/LA) circuit on the fabricated AWG-PD device using flip-chip bonding technology. The results show the promising potential of our Si photonic platform as a photonics-electronics convergence.

Effect of chromatographic conditions and plasmid DNA size on the dynamic binding capacity of a monolithic support.

PubMed

Bicho, Diana; Sousa, Ângela; Sousa, Fani; Queiroz, João; Tomaz, Cãndida

2014-09-01

DNA therapies are becoming recognized alternatives for the treatment and prevention of severe pathologies. Although most current trials have used plasmids <10 kbp, in the future larger plasmids would be required. The purpose of this work was to study the chromatographic behavior of nongrafted carbonyldiimidazole monolithic disks using plasmids with different sizes under hydrophobic conditions. Thereunto, the purification of several plasmids was performed. Higher size plasmids needed lower ammonium sulfate concentration, due to the greater number of interactions between the plasmids and monolith. The dynamic binding capacity experiments for the different plasmids revealed a lower capacity for bigger plasmids. It was also verified that the increase of salt concentration from 2.5 to 3 M of ammonium sulfate increased the capacity. At the highest salt concentration, a slight improvement in the capacity using lower flow rate was observed, possibly due to compaction of plasmid molecules and its better organization on the monolith channels. Finally, a low pH also had a positive effect on the capacity. So, this monolithic support proved to be appropriate to purify the supercoiled isoform of different plasmids with different sizes, providing a valuable instrument as a purification technique. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hydrodynamic chromatography of macromolecules using polymer monolithic columns.

PubMed

Edam, Rob; Eeltink, Sebastiaan; Vanhoutte, Dominique J D; Kok, Wim Th; Schoenmakers, Peter J

2011-12-02

The selectivity window of size-based separations of macromolecules was tailored by tuning the macropore size of polymer monolithic columns. Monolithic materials with pore sizes ranging between 75 nm and 1.2 μm were prepared in situ in large I.D. columns. The dominant separation mechanism was hydrodynamic chromatography in the flow-through pores. The calibration curves for synthetic polymers matched with the elution behavior by HDC separations in packed columns with 'analyte-to-pore' aspect ratios (λ) up to 0.2. For large-macropore monoliths, a deviation in retention behavior was observed for small polystyrene polymers (M(r)<20 kDa), which may be explained by a combined HDC-SEC mechanism for λ<0.02. The availability of monoliths with very narrow pore sizes allowed investigation of separations at high λ values. For high-molecular weight polymers (M(r)>300,000 Da) confined in narrow channels, the separation strongly depended on flow rate. Flow-rate dependent elution behavior was evaluated by calculation of Deborah numbers and confirmed to be outside the scope of classic shear deformation or slalom chromatography. Shear-induced forces acting on the periphery of coiled polymers in solution may be responsible for flow-rate dependent elution. Copyright © 2011 Elsevier B.V. All rights reserved.

Poincaré plot analysis of ultra-short-term heart rate variability during recovery from exercise in physically active men.

PubMed

Gomes, Rayana L; Marques Vanderlei, Luiz C; Garner, David M; Ramos Santana, Milana D; de Abreu, Luiz C; Valenti, Vitor E

2017-04-26

Recently there has been increasing interest in the study of ultra-short- term heart rate variability (HRV) in sports performance and exercise physiology. In order to improve standardization of this specific analysis, we evaluated the ultra-short-term HRV analysis through SD1Poincaré index to identify exercise induced responses. We investigated 35 physically active men aged between 18 and 35 years old. Volunteers performed physical exercise on treadmill with intensity of 6.0 km / hour + 1% slope in the first five minutes for physical "warming up." This was followed by 25 minutes with intensity equivalent to 60% of Vmax, with the same slope according to the Conconi threshold. HRV was analyzed in the following periods: the five-minute period before the exercise and the five-minute period immediately after the exercise, the five minutes were divided into five segments of 60 RR intervals. Ultra-short-term RMSSD and SD1 analysis were performed. Ultra-short-term RMSSD and SD1 were significantly (p<0.0001) reduced during the initial five minutes divided into five segments of 60 RR intervals compared to (at rest) control. Heart rate was significantly (p<0.0001) increased 1 min and 3 min immediately after exercise compared to (at rest) control. At rest ultra-short-term SD1 presented significant correlation with short-term (256 RR intervals) RMSSD (r=0.78; p<0.0001), HF (r=0.574; p=0.0007) and SD1 (r=0.78; p<0.0001). Additionally, visual analysis with the Poincaré plot detected changes in HRV after exercise. Ultra-short-term HRV analysis through Poincaré plot identified heart rate autonomic responses induced by aerobic exercise.

Flexible metasurface black nickel with stepped nanopillars.

PubMed

Qian, Qinyu; Yan, Ying; Wang, Chinhua

2018-03-15

We report on a monolithic, all-metallic, and flexible metasurface perfect absorber [black nickel (Ni)] based on coupled Mie resonances originated from vertically stepped Ni nanopillars homoepitaxially grown on an Ni substrate. Coupled Mie resonances are generated from Ni nanopillars with different sizes such that Mie resonances of the stepped two sets of Ni nanopillars occur complementarily at different wavelengths to realize polarization-independent broadband absorption over the entire visible wavelength band (400-760 nm) within an ultra-thin surface layer of only 162 nm thick in total. Two-step double-beam interference lithography and electroplating are utilized to fabricate the proposed monolithic metasurface that can be arbitrarily bent and pressed. A black nickel metasurface is experimentally demonstrated in which an average polarization-independent absorption of 0.972 (0.961, experiment) in the entire visible band is achieved and remains 0.838 (0.815, experiment) when the incident angle increases to 70°.

Evaluation of the capability of local helioseismology to discern between monolithic and spaghetti sunspot models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Felipe, T.; Crouch, A. D.; Birch, A. C., E-mail: tobias@nwra.com

2014-06-20

The helioseismic properties of the wave scattering generated by monolithic and spaghetti sunspots are analyzed by means of numerical simulations. In these computations, an incident f- or p {sub 1}-mode travels through the sunspot model, which produces absorption and phase shift of the waves. The scattering is studied by inspecting the wavefield, computing travel-time shifts, and performing Fourier-Hankel analysis. The comparison between the results obtained for both sunspot models reveals that the differences in the absorption coefficient can be detected above noise level. The spaghetti model produces a steep increase of the phase shift with the degree of the modemore » at short wavelengths, while mode mixing is more efficient for the monolithic model. These results provide a clue for what to look for in solar observations to discern the constitution of sunspots between the proposed monolithic and spaghetti models.« less

Ultra-high gradient channeling acceleration in nanostructures: Design/progress of proof-of-concept (POC) experiments

NASA Astrophysics Data System (ADS)

Shin, Y. M.; Green, A.; Lumpkin, A. H.; Thurman-Keup, R. M.; Shiltsev, V.; Zhang, X.; Farinella, D. M.-A.; Taborek, P.; Tajima, T.; Wheeler, J. A.; Mourou, G.

2017-03-01

A short bunch of relativistic particles, or a short-pulse laser, perturb the density state of conduction electrons in a solid crystal and excite wakefields along atomic lattices in a crystal. Under a coupling condition between a driver and plasma, the wakes, if excited, can accelerate channeling particles with TeV/m acceleration gradients [1], in principle, since the density of charge carriers (conduction electrons) in solids n0 = 1020 - 1023 cm-3 is significantly higher than what was considered above in gaseous plasma. Nanostructures have some advantages over crystals for channeling applications of high power beams. The de-channeling rate can be reduced and the beam acceptance increased by the large size of the channels. For beam-driven acceleration, a bunch length with a sufficient charge density would need to be in the range of the plasma wavelength to properly excite plasma wakefields, and channeled particle acceleration with the wakefields must occur before the ions in the lattices move beyond the restoring threshold. In the case of the excitation by short laser pulses, the dephasing length is appreciably increased with the larger channel, which enables channeled particles to gain sufficient amounts of energy. This paper describes simulation analyses on beam- and laser (X-ray)-driven accelerations in effective nanotube models obtained from the Vsim and EPOCH codes. Experimental setups to detect wakefields are also outlined with accelerator facilities at Fermilab and Northern Illinois University (NIU). In the FAST facility, the electron beamline was successfully commissioned at 50 MeV, and it is being upgraded toward higher energies for electron accelerator R&D. The 50 MeV injector beamline of the facility is used for X-ray crystal-channeling radiation with a diamond target. It has been proposed to utilize the same diamond crystal for a channeling acceleration proof-of-concept (POC). Another POC experiment is also designed for the NIU accelerator lab with time-resolved electron diffraction. Recently, a stable generation of single-cycle laser pulses with tens of Petawatt power based on the thin film compression (TFC) technique has been investigated for target normal sheath acceleration (TNSA) and radiation pressure acceleration (RPA). The experimental plan with a nanometer foil is discussed with an available test facility such as Extreme Light Infrastructure - Nuclear Physics (ELI-NP).

UTBB FDSOI: Evolution and opportunities

NASA Astrophysics Data System (ADS)

Monfray, Stephane; Skotnicki, Thomas

2016-11-01

As today's 28 nm FDSOI (Fully Depleted Silicon On Insulator) technology is at the industrialization level, this paper aims to summarize the key advantages allowed by the thin BOX (Buried Oxide) of the FDSOI, through the technology evolution but also new opportunities, among logic applications and extending the possibilities offered by the platform. We will summarize how the advantages provided by the thin BOX have been first explored and developed, and how the back biasing techniques are the key to the outstanding performances provided by the FDSOI at low voltage. Then, as the FDSOI technology is also a solution to develop innovative platforms and applications, we will detail some opportunities. In particular, we will present monolithic 3D integration, ultra-low power devices for IoT (Internet of Things) and ultra-sensitive sensors.

Advanced mirror technology development (AMTD): year five status

NASA Astrophysics Data System (ADS)

Stahl, H. Philip

2017-09-01

The Advanced Mirror Technology Development (AMTD) project is in Phase 2 of a multiyear effort initiated in Fiscal Year (FY) 2012, to mature the Technology Readiness Level (TRL) of critical technologies required to enable 4-m-orlarger monolithic or segmented ultraviolet, optical, and infrared (UVOIR) space telescope primary-mirror assemblies for general astrophysics, ultra-high-contrast observations of exoplanets, and National Interest missions. Key accomplishments of 2016/17 include the completion of the Harris Corp 150 Hz 1.5-meter Ultra-Low Expansion (ULE) mirror substrate using stacked core method to demonstrate lateral stability of the stacked core technology, as well as the characterization and validation by test of the mechanical and thermal performance of the 1.2-meter Zerodur mirror using the STOP model prediction and verification of CTE homogeneity.

DEVELOPMENT OF AEROBIC BIOFILTER DESIGN CRITERIA FOR TREATING VOCS

EPA Science Inventory

This paper reports preliminary results on the use of trickle bed biofilters with monolithic ceramic channelized microbial support structures for the treatment of VOCs typical of landfill leachate stripping. Toluene was used for the purpose of characterizing the trickle bed biofi...

SERVER DEVELOPMENT FOR NSLS-II PHYSICS APPLICATIONS AND PERFORMANCE ANALYSIS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shen, G.; Kraimer, M.

2011-03-28

The beam commissioning software framework of NSLS-II project adopts a client/server based architecture to replace the more traditional monolithic high level application approach. The server software under development is available via an open source sourceforge project named epics-pvdata, which consists of modules pvData, pvAccess, pvIOC, and pvService. Examples of two services that already exist in the pvService module are itemFinder, and gather. Each service uses pvData to store in-memory transient data, pvService to transfer data over the network, and pvIOC as the service engine. The performance benchmarking for pvAccess and both gather service and item finder service are presented inmore » this paper. The performance comparison between pvAccess and Channel Access are presented also. For an ultra low emittance synchrotron radiation light source like NSLS II, the control system requirements, especially for beam control are tight. To control and manipulate the beam effectively, a use case study has been performed to satisfy the requirement and theoretical evaluation has been performed. The analysis shows that model based control is indispensable for beam commissioning and routine operation. However, there are many challenges such as how to re-use a design model for on-line model based control, and how to combine the numerical methods for modeling of a realistic lattice with the analytical techniques for analysis of its properties. To satisfy the requirements and challenges, adequate system architecture for the software framework for beam commissioning and operation is critical. The existing traditional approaches are self-consistent, and monolithic. Some of them have adopted a concept of middle layer to separate low level hardware processing from numerical algorithm computing, physics modelling, data manipulating and plotting, and error handling. However, none of the existing approaches can satisfy the requirement. A new design has been proposed by introducing service oriented architecture technology, and client interface is undergoing. The design and implementation adopted a new EPICS implementation, namely epics-pvdata [9], which is under active development. The implementation of this project under Java is close to stable, and binding to other language such as C++ and/or Python is undergoing. In this paper, we focus on the performance benchmarking and comparison for pvAccess and Channel Access, the performance evaluation for 2 services, gather and item finder respectively.« less

Length of Barrett's oesophagus and cancer risk: implications from a large sample of patients with early oesophageal adenocarcinoma.

PubMed

Pohl, Heiko; Pech, Oliver; Arash, Haris; Stolte, Manfred; Manner, Hendrik; May, Andrea; Kraywinkel, Klaus; Sonnenberg, Amnon; Ell, Christian

2016-02-01

Although it is well understood that the risk of oesophageal adenocarcinoma increases with Barrett length, transition risks for cancer associated with different Barrett lengths are unknown. We aimed to estimate annual cancer transition rates for patients with long-segment (≥3 cm), short-segment (≥1 to <3 cm) and ultra-short-segment (<1 cm) Barrett's oesophagus. We used three data sources to estimate the annual cancer transition rates for each Barrett length category: (1) the distribution of long, short and ultra-short Barrett's oesophagus among a large German cohort with newly diagnosed T1 oesophageal adenocarcinoma; (2) population-based German incidence of oesophageal adenocarcinoma; and (3) published estimates of the population prevalence of Barrett's oesophagus for each Barrett length category. Among 1017 patients with newly diagnosed T1 oesophageal adenocarcinoma, 573 (56%) had long-segment, 240 (24%) short-segment and 204 (20%) ultra-short-segment Barrett's oesophagus. The base-case estimates for the prevalence of Barrett's oesophagus among the general population were 1.5%, 5% and 14%, respectively. The annual cancer transition rates for patients with long, short and ultra-short Barrett's oesophagus were 0.22%, 0.03% and 0.01%, respectively. To detect one cancer, 450 patients with long-segment Barrett's oesophagus would need to undergo annual surveillance endoscopy; in short segment and ultra-short segment, the corresponding numbers of patients would be 3440 and 12,364. Similar results were obtained when applying US incidence data. The large number of patients, who need to undergo endoscopic surveillance to detect one cancer, raises questions about the value of surveillance endoscopy in patients with short segment or ultra-short segment of Barrett's oesophagus. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Ultra-High Gradient Channeling Acceleration in Nanostructures: Design/Progress of Proof-of-Concept (POC) Experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shin, Young Min; Green, A.; Lumpkin, A. H.

2016-09-16

A short bunch of relativistic particles or a short-pulse laser perturbs the density state of conduction electrons in a solid crystal and excites wakefields along atomic lattices in a crystal. Under a coupling condition the wakes, if excited, can accelerate channeling particles with TeV/m acceleration gradients in principle since the density of charge carriers (conduction electrons) in solids n 0 = ~ 10 20 – 10 23 cm -3 is significantly higher than what can be obtained in gaseous plasma. Nanostructures have some advantages over crystals for channeling applications of high power beams. The dechanneling rate can be reduced andmore » the beam acceptance increased by the large size of the channels. For beam-driven acceleration, a bunch length with a sufficient charge density would need to be in the range of the plasma wavelength to properly excite plasma wakefields, and channeled particle acceleration with the wakefields must occur before the ions in the lattices move beyond the restoring threshold. In the case of the excitation by short laser pulses, the dephasing length is appreciably increased with the larger channel, which enables channeled particles to gain sufficient amounts of energy. This paper describes simulation analyses on beam- and laser (X-ray)-driven accelerations in effective nanotube models obtained from Vsim and EPOCH codes. Experimental setups to detect wakefields are also outlined with accelerator facilities at Fermilab and NIU. In the FAST facility, the electron beamline was successfully commissioned at 50 MeV and it is being upgraded toward higher energies for electron accelerator R&D. The 50 MeV injector beamline of the facility is used for X-ray crystal-channeling radiation with a diamond target. It has been proposed to utilize the same diamond crystal for a channeling acceleration POC test. Another POC experiment is also designed for the NIU accelerator lab with time-resolved electron diffraction. Recently, a stable generation of single-cycle laser pulses with tens of Petawatt power based on thin film compression (TFC) technique has been investigated for target normal sheath acceleration (TNSA) and radiation pressure acceleration (RPA). The experimental plan with a nanometer foil is discussed with an available test facility such as Extreme Light Infrastructure – Nuclear Physics (ELI-NP).« less

Micro-Laser Range Finder Development: Using the Monolithic Approach

DTIC Science & Technology

1999-02-01

components can be joined together, optically aligned to form the laser cavity and then sliced to produce MLC modules . This batch process can greatly reduce...the overall fabrication costs of the µLRF system. The MLC module is ultra-compact. Its overall size is approximately 56 mm (L) x 3 mm (W) x 3 mm (H) as...MLC module is placed on a laser pallet for stiffness, mechanical stability. The laser pallet size is selected as part of the integration design

High quality-factor fano metasurface comprising a single resonator unit cell

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sinclair, Michael B.; Warne, Larry K.; Basilio, Lorena I.

A new monolithic resonator metasurface design achieves ultra-high Q-factors while using only one resonator per unit cell. The metasurface relies on breaking the symmetry of otherwise highly symmetric resonators to induce intra-resonator mixing of bright and dark modes (rather than inter-resonator couplings), and is scalable from the near-infrared to radio frequencies and can be easily implemented in dielectric materials. The resulting high-quality-factor Fano metasurface can be used in many sensing, spectral filtering, and modulation applications.

Integrated electrokinetically driven microfluidic devices with pH-mediated solid-phase extraction coupled to microchip electrophoresis for preterm birth biomarkers.

PubMed

Sonker, Mukul; Knob, Radim; Sahore, Vishal; Woolley, Adam T

2017-07-01

Integration in microfluidics is important for achieving automation. Sample preconcentration integrated with separation in a microfluidic setup can have a substantial impact on rapid analysis of low-abundance disease biomarkers. Here, we have developed a microfluidic device that uses pH-mediated solid-phase extraction (SPE) for the enrichment and elution of preterm birth (PTB) biomarkers. Furthermore, this SPE module was integrated with microchip electrophoresis for combined enrichment and separation of multiple analytes, including a PTB peptide biomarker (P1). A reversed-phase octyl methacrylate monolith was polymerized as the SPE medium in polyethylene glycol diacrylate modified cyclic olefin copolymer microfluidic channels. Eluent for pH-mediated SPE of PTB biomarkers on the monolith was optimized using different pH values and ionic concentrations. Nearly 50-fold enrichment was observed in single channel SPE devices for a low nanomolar solution of P1, with great elution time reproducibility (<7% RSD). The monolith binding capacity was determined to be 400 pg (0.2 pmol). A mixture of a model peptide (FA) and a PTB biomarker (P1) was extracted, eluted, injected, and then separated by microchip electrophoresis in our integrated device with ∼15-fold enrichment. This device shows important progress towards an integrated electrokinetically operated platform for preconcentration and separation of biomarkers. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

CVD SiC deformable mirror with monolithic cooling channels.

PubMed

Ahn, Kyohoon; Rhee, Hyug-Gyo; Yang, Ho-Soon; Kihm, Hagyong

2018-04-16

We propose a novel deformable mirror (DM) for adaptive optics in high power laser applications. The mirror is made of a Silicon carbide (SiC) faceplate, and cooling channels are embedded monolithically inside the faceplate with the chemical vapor desposition (CVD) method. The faceplate is 200 mm in diameter and 3 mm in thickness, and is actuated by 137 stack-type piezoelectric transducers arranged in a square grid. We also propose a new actuator influence function optimized for modelling our DM, which has a relatively stiffer faceplate and a higher coupling ratio compared with other DMs having thin faceplates. The cooling capability and optical performance of the DM are verified by simulations and actual experiments with a heat source. The DM is proved to operate at 1 kHz without the coolant flow and 100 Hz with the coolant flow, and the residual errors after compensation are less than 30 nm rms (root-mean-square). This paper presents the design, fabrication, and optical performance of the CVD SiC DM.

LDMOS Channel Thermometer Based on a Thermal Resistance Sensor for Balancing Temperature in Monolithic Power ICs.

PubMed

Lin, Tingyou; Ho, Yingchieh; Su, Chauchin

2017-06-15

This paper presents a method of thermal balancing for monolithic power integrated circuits (ICs). An on-chip temperature monitoring sensor that consists of a poly resistor strip in each of multiple parallel MOSFET banks is developed. A temperature-to-frequency converter (TFC) is proposed to quantize on-chip temperature. A pulse-width-modulation (PWM) methodology is developed to balance the channel temperature based on the quantization. The modulated PWM pulses control the hottest of metal-oxide-semiconductor field-effect transistor (MOSFET) bank to reduce its power dissipation and heat generation. A test chip with eight parallel MOSFET banks is fabricated in TSMC 0.25 μm HV BCD processes, and total area is 900 × 914 μm². The maximal temperature variation among the eight banks can reduce to 2.8 °C by the proposed thermal balancing system from 9.5 °C with 1.5 W dissipation. As a result, our proposed system improves the lifetime of a power MOSFET by 20%.

LDMOS Channel Thermometer Based on a Thermal Resistance Sensor for Balancing Temperature in Monolithic Power ICs

PubMed Central

Lin, Tingyou; Ho, Yingchieh; Su, Chauchin

2017-01-01

This paper presents a method of thermal balancing for monolithic power integrated circuits (ICs). An on-chip temperature monitoring sensor that consists of a poly resistor strip in each of multiple parallel MOSFET banks is developed. A temperature-to-frequency converter (TFC) is proposed to quantize on-chip temperature. A pulse-width-modulation (PWM) methodology is developed to balance the channel temperature based on the quantization. The modulated PWM pulses control the hottest of metal-oxide-semiconductor field-effect transistor (MOSFET) bank to reduce its power dissipation and heat generation. A test chip with eight parallel MOSFET banks is fabricated in TSMC 0.25 μm HV BCD processes, and total area is 900 × 914 μm2. The maximal temperature variation among the eight banks can reduce to 2.8 °C by the proposed thermal balancing system from 9.5 °C with 1.5 W dissipation. As a result, our proposed system improves the lifetime of a power MOSFET by 20%. PMID:28617346

Dual-beam optical trapping of cells in an optofluidic device fabricated by femtosecond lasers

NASA Astrophysics Data System (ADS)

Bellini, N.; Bragheri, F.; Vishnubhatla, K. C.; Ferrara, L.; Minzioni, P.; Cerullo, G.; Ramponi, R.; Cristiani, I.; Osellame, R.

2010-02-01

We present design and optimization of an optofluidic monolithic chip, able to provide optical trapping and controlled stretching of single cells. The chip is fabricated in a fused silica glass substrate by femtosecond laser micromachining, which can produce both optical waveguides and microfluidic channels with great accuracy. Versatility and three-dimensional capabilities of this fabrication technology provide the possibility to fabricate circular cross-section channels with enlarged access holes for an easy connection with an external fluidic circuit. Moreover, a new fabrication procedure adopted allows the demonstration of microchannels with a square cross-section, thus guaranteeing an improved quality of the trapped cell images. Optical trapping and stretching of single red blood cells are demonstrated, thus proving the effectiveness of the proposed device as a monolithic optical stretcher. We believe that femtosecond laser micromachining represents a promising technique for the development of multifunctional integrated biophotonic devices that can be easily coupled to a microscope platform, thus enabling a complete characterization of the cells under test.

Ultra-Short-Term Heart Rate Variability is Sensitive to Training Effects in Team Sports Players.

PubMed

Nakamura, Fabio Y; Flatt, Andrew A; Pereira, Lucas A; Ramirez-Campillo, Rodrigo; Loturco, Irineu; Esco, Michael R

2015-09-01

The aim of this study was to test the possibility of the ultra-short-term lnRMSSD (measured in 1-min post-1-min stabilization period) to detect training induced adaptations in futsal players. Twenty-four elite futsal players underwent HRV assessments pre- and post-three or four weeks preseason training. From the 10-min HRV recording period, lnRMSSD was analyzed in the following time segments: 1) from 0-5 min (i.e., stabilization period); 2) from 0-1 min; 1-2 min; 2-3 min; 3-4 min; 4-5 min and; 3) from 5-10 min (i.e., criterion period). The lnRMSSD was almost certainly higher (100/00/00) using the magnitude-based inference in all periods at the post- moment. The correlation between changes in ultra-short-term lnRMSSD (i.e., 0-1 min; 1-2 min; 2-3 min; 3-4 min; 4-5 min) and lnRMSSDCriterion ranged between 0.45-0.75, with the highest value (p = 0.75; 90% CI: 0.55 - 0.85) found between ultra-short-term lnRMDSSD at 1-2 min and lnRMSSDCriterion. In conclusion, lnRMSSD determined in a short period of 1-min is sensitive to training induced changes in futsal players (based on the very large correlation to the criterion measure), and can be used to track cardiac autonomic adaptations. Key pointsThe ultra-short-term (1 min) natural log of the root-mean-square difference of successive normal RR intervals (lnRMSSD) is sensitive to training effects in futsal playersThe ultra-short-term lnRMSSD may simplify the assessment of the cardiac autonomic changes in the field compared to the traditional and lengthier (10 min duration) analysisCoaches are encouraged to implement the ultra-short-term heart rate variability in their routines to monitor team sports athletes.

Ultra-Short-Term Heart Rate Variability is Sensitive to Training Effects in Team Sports Players

PubMed Central

Nakamura, Fabio Y.; Flatt, Andrew A.; Pereira, Lucas A.; Ramirez-Campillo, Rodrigo; Loturco, Irineu; Esco, Michael R.

2015-01-01

The aim of this study was to test the possibility of the ultra-short-term lnRMSSD (measured in 1-min post-1-min stabilization period) to detect training induced adaptations in futsal players. Twenty-four elite futsal players underwent HRV assessments pre- and post-three or four weeks preseason training. From the 10-min HRV recording period, lnRMSSD was analyzed in the following time segments: 1) from 0-5 min (i.e., stabilization period); 2) from 0-1 min; 1-2 min; 2-3 min; 3-4 min; 4-5 min and; 3) from 5-10 min (i.e., criterion period). The lnRMSSD was almost certainly higher (100/00/00) using the magnitude-based inference in all periods at the post- moment. The correlation between changes in ultra-short-term lnRMSSD (i.e., 0-1 min; 1-2 min; 2-3 min; 3-4 min; 4-5 min) and lnRMSSDCriterion ranged between 0.45-0.75, with the highest value (p = 0.75; 90% CI: 0.55 – 0.85) found between ultra-short-term lnRMDSSD at 1-2 min and lnRMSSDCriterion. In conclusion, lnRMSSD determined in a short period of 1-min is sensitive to training induced changes in futsal players (based on the very large correlation to the criterion measure), and can be used to track cardiac autonomic adaptations. Key points The ultra-short-term (1 min) natural log of the root-mean-square difference of successive normal RR intervals (lnRMSSD) is sensitive to training effects in futsal players The ultra-short-term lnRMSSD may simplify the assessment of the cardiac autonomic changes in the field compared to the traditional and lengthier (10 min duration) analysis Coaches are encouraged to implement the ultra-short-term heart rate variability in their routines to monitor team sports athletes PMID:26336347

Sequence-specific sepsis-related DNA capture and fluorescent labeling in monoliths prepared by single-step photopolymerization in microfluidic devices.

PubMed

Knob, Radim; Hanson, Robert L; Tateoka, Olivia B; Wood, Ryan L; Guerrero-Arguero, Israel; Robison, Richard A; Pitt, William G; Woolley, Adam T

2018-05-21

Fast determination of antibiotic resistance is crucial in selecting appropriate treatment for sepsis patients, but current methods based on culture are time consuming. We are developing a microfluidic platform with a monolithic column modified with oligonucleotides designed for sequence-specific capture of target DNA related to the Klebsiella pneumoniae carbapenemase (KPC) gene. We developed a novel single-step monolith fabrication method with an acrydite-modified capture oligonucleotide in the polymerization mixture, enabling fast monolith preparation in a microfluidic channel using UV photopolymerization. These prepared columns had a threefold higher capacity compared to monoliths prepared in a multistep process involving Schiff-base DNA attachment. Conditions for denaturing, capture and fluorescence labeling using hybridization probes were optimized with synthetic 90-mer oligonucleotides. These procedures were applied for extraction of a PCR amplicon from the KPC antibiotic resistance gene in bacterial lysate obtained from a blood sample spiked with E. coli. The results showed similar eluted peak areas for KPC amplicon extracted from either hybridization buffer or bacterial lysate. Selective extraction of the KPC DNA was verified by real time PCR on eluted fractions. These results show great promise for application in an integrated microfluidic diagnostic system that combines upstream blood sample preparation and downstream single-molecule counting detection. Copyright © 2018 Elsevier B.V. All rights reserved.

A Bionic Neural Link for peripheral nerve repair.

PubMed

Xu, Yong Ping; Yen, Shih-Cheng; Ng, Kian Ann; Liu, Xu; Tan, Ter Chyan

2012-01-01

Peripheral nerve injuries with large gaps and long nerve regrowth paths are difficult to repair using existing surgical techniques, due to nerve degeneration and muscle atrophy. This paper proposes a Bionic Neural Link (BNL) as an alternative way for peripheral nerve repair. The concept of the BNL is described, along with the hypothetical benefits. A prototype monolithic single channel BNL has been developed, which consists of 16 neural recording channels and one stimulation channel, and is implemented in a 0.35-µm CMOS technology. The BNL has been tested in in-vivo animal experiments. Full function of the BNL chip has been demonstrated.

Low-Power and High-Speed Technique for logic Gates in 20nm Double-Gate FinFET Technology

NASA Astrophysics Data System (ADS)

Priydarshi, A.; Chattopadhyay, M. K.

2016-10-01

The FinFET is the leading example of multigate MOSFETS to substitute conventional single gate MOSFETs for ultimate scaling [1], The FinFET structure is a combination of a thin channel region and a double gate to suppress the short channel effects (SCEs) and Vthvariation [2], By using FinFET,figure of merits viz, ION, IOFF, output resistance, propagation delay, noise margin and leakage power, can be improved for ultra low power and high performance applications[3]. In this paper, a new high speed low power dynamic circuit design technique has been proposed using 20nm FinFETs. By applying the appropriate clock and sleep signal to the back gates of the FinFETs, the proposed circuit can efficiently control the dynamic power, During the pre-charging period, Vth of PMOS is controlled low so that a fast precharging can occur;

Kink effect in ultrathin FDSOI MOSFETs

NASA Astrophysics Data System (ADS)

Park, H. J.; Bawedin, M.; Choi, H. G.; Cristoloveanu, S.

2018-05-01

Systematic experiments demonstrate the presence of the kink effect even in FDSOI MOSFETs. The back-gate bias controls the kink effect via the formation of a back accumulation channel. The kink is more or less pronounced according to the film thickness and channel length. However, in ultrathin (<10 nm) and/or very short transistors (L < 50 nm), the kink is totally absent as a consequence of super-coupling effect. For the first time, thanks to the availability of body contacts, the body potential is probed to evidence the impact of majority carrier accumulation and drain pulse duration on the kink effect onset. He is currently working toward the Ph.D. degree in FDSOI device characterization and simulation at a laboratory of IMEP-lahc, Université Grenoble Alpes, Minatec, Grenoble, France. His research interests include residual floating body effects, electrical characterization, and device simulation for ultra FDSOI MOSFETs.

A quantum wave based compact modeling approach for the current in ultra-short DG MOSFETs suitable for rapid multi-scale simulations

NASA Astrophysics Data System (ADS)

Hosenfeld, Fabian; Horst, Fabian; Iñíguez, Benjamín; Lime, François; Kloes, Alexander

2017-11-01

Source-to-drain (SD) tunneling decreases the device performance in MOSFETs falling below the 10 nm channel length. Modeling quantum mechanical effects including SD tunneling has gained more importance specially for compact model developers. The non-equilibrium Green's function (NEGF) has become a state-of-the-art method for nano-scaled device simulation in the past years. In the sense of a multi-scale simulation approach it is necessary to bridge the gap between compact models with their fast and efficient calculation of the device current, and numerical device models which consider quantum effects of nano-scaled devices. In this work, an NEGF based analytical model for nano-scaled double-gate (DG) MOSFETs is introduced. The model consists of a closed-form potential solution of a classical compact model and a 1D NEGF formalism for calculating the device current, taking into account quantum mechanical effects. The potential calculation omits the iterative coupling and allows the straightforward current calculation. The model is based on a ballistic NEGF approach whereby backscattering effects are considered as second order effect in a closed-form. The accuracy and scalability of the non-iterative DG MOSFET model is inspected in comparison with numerical NanoMOS TCAD data for various channel lengths. With the help of this model investigations on short-channel and temperature effects are performed.

High-performance hybrid complementary logic inverter through monolithic integration of a MEMS switch and an oxide TFT.

PubMed

Song, Yong-Ha; Ahn, Sang-Joon Kenny; Kim, Min-Wu; Lee, Jeong-Oen; Hwang, Chi-Sun; Pi, Jae-Eun; Ko, Seung-Deok; Choi, Kwang-Wook; Park, Sang-Hee Ko; Yoon, Jun-Bo

2015-03-25

A hybrid complementary logic inverter consisting of a microelectromechanical system switch as a promising alternative for the p-type oxide thin film transistor (TFT) and an n-type oxide TFT is presented for ultralow power integrated circuits. These heterogeneous microdevices are monolithically integrated. The resulting logic device shows a distinctive voltage transfer characteristic curve, very low static leakage, zero-short circuit current, and exceedingly high voltage gain. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

How short are ultra short light pulses? (looking back to the mid sixties)

NASA Astrophysics Data System (ADS)

Weber, H. P.; Dändliker, R.

2010-09-01

With the arrival of mode locking for Q-switched lasers to generate ultra short light pulses, a method to measure their expected time duration in the psec range was needed. A novel method, based on an intensity correlation measurement using optical second harmonic generation, was developed. Other reported approaches for the same purpose were critically analysed. Theoretical and subsequent experimental studies lead to surprising new insight into the ultra fast temporal behaviour of broadband laser radiation: Any non mode locked multimode emission of a laser consists of random intensity fluctuations with duration of the total inverse band width of emitted radiation. However, it was shown, that with mode locking isolated ultra short pulses of psec duration can be generated. This article summarizes activities performed in the mid sixties at the University of Berne, Switzerland.

Characterization of an Ultra-High Temperature Ceramic Composite

NASA Technical Reports Server (NTRS)

Levine, Stanley R.; Opila, Elizabeth J.; Robinson, Raymond C.; Lorincz, Jonathan A.

2004-01-01

Ultra-high temperature ceramics (UHTC) are of interest for hypersonic vehicle leading edge applications. Monolithic UHTCs are of concern because of their low fracture toughness and brittle behavior. UHTC composites (UHTCC) are being investigated as a possible approach to overcome these deficiencies. In this study a small sample of a UHTCC was evaluated by limited mechanical property tests, furnace oxidation exposures, and oxidation exposures in a flowing environment generated by an oxy-acetylene torch. The composite was prepared from a carbon fiber perform using ceramic particulates and a pre-cerns about microcracking due to thermal expansion mismatch between the matrix and the carbon fiber reinforcements, and about the oxidation resistance of the HfB2-SiC coating layer and the composite constituents. However, positive performance in the torch test warrants further study of this concept.

Advanced Mirror Technology Development (AMTD): Year Five Status

NASA Technical Reports Server (NTRS)

Stahl, H Philip

2017-01-01

The Advanced Mirror Technology Development (AMTD) project is in Phase 2 of a multiyear effort initiated in Fiscal Year (FY) 2012, to mature the Technology Readiness Level (TRL) of critical technologies required to enable 4-m-or-larger monolithic or segmented ultraviolet, optical, and infrared (UVOIR) space telescope primary-mirror assemblies for general astrophysics, ultra-high-contrast observations of exoplanets, and National Interest missions. Key accomplishments of 2016/17 include the completion of the Harris Corp approximately 150 Hz 1.5-meter Ultra-Low Expansion (ULE Registered trademark) mirror substrate using stacked core method to demonstrate lateral stability of the stacked core technology, as well as the characterization and validation by test of the mechanical and thermal performance of the 1.2-meter Zerodur (Registered trademark) mirror using the STOP model prediction and verification of CTE homogeneity.

UHF Television: Breaking the Monolith

ERIC Educational Resources Information Center

Oppenheim, Jerrold

1975-01-01

Advocates that the Federal Communications Council should remove unnecessary UHF restrictions to dramatically increase the number of UHF stations, put all existing stations on the UHF band, and license new low-power stations on the UHF channels, arguing that television fails to serve a sizable number of viewers. (Author/JM)

Silicon photonic dynamic optical channel leveler with external feedback loop.

PubMed

Doylend, J K; Jessop, P E; Knights, A P

2010-06-21

We demonstrate a dynamic optical channel leveler composed of a variable optical attenuator (VOA) integrated monolithically with a defect-mediated photodiode in a silicon photonic waveguide device. An external feedback loop mimics an analog circuit such that the photodiode directly controls the VOA to provide blind channel leveling within +/-1 dB across a 7-10 dB dynamic range for wavelengths from 1530 nm to 1570 nm. The device consumes approximately 50 mW electrical power and occupies a 6 mm x 0.1 mm footprint per channel. Dynamic leveling is accomplished without tapping optical power from the output path to the photodiode and thus the loss penalty is minimized.

1D-VAR Retrieval Using Superchannels

NASA Technical Reports Server (NTRS)

Liu, Xu; Zhou, Daniel; Larar, Allen; Smith, William L.; Schluessel, Peter; Mango, Stephen; SaintGermain, Karen

2008-01-01

Since modern ultra-spectral remote sensors have thousands of channels, it is difficult to include all of them in a 1D-var retrieval system. We will describe a physical inversion algorithm, which includes all available channels for the atmospheric temperature, moisture, cloud, and surface parameter retrievals. Both the forward model and the inversion algorithm compress the channel radiances into super channels. These super channels are obtained by projecting the radiance spectra onto a set of pre-calculated eigenvectors. The forward model provides both super channel properties and jacobian in EOF space directly. For ultra-spectral sensors such as Infrared Atmospheric Sounding Interferometer (IASI) and the NPOESS Airborne Sounder Testbed Interferometer (NAST), a compression ratio of more than 80 can be achieved, leading to a significant reduction in computations involved in an inversion process. Results will be shown applying the algorithm to real IASI and NAST data.

In situ control of synchronous germanide/silicide reactions with Ge/Si core/shell nanowires to monitor formation and strain evolution in abrupt 2.7 nm channel length

DOE PAGES

Chen, Renjie; Nguyen, Binh-Minh; Tang, Wei; ...

2017-05-22

The metal-semiconductor interface in self-aligned contact formation can determine the overall performance of nanoscale devices. This interfacial morphology is predicted and well researched in homogenous semiconductor nanowires (NWs) but was not pursued in heterostructured core/shell nanowires. Here, we found here that the solid-state reactions between Ni and Ge/Si core/shell nanowires resulted in a protruded and a leading NiSiy segment into the channel. A single Ni 2Ge/NiSi y to Ge/Si core/shell interface was achieved by the selective shell removal near the Ni source/drain contact areas. In using in situ transmission electron microscopy, we measured the growth rate and anisotropic strain evolutionmore » in ultra-short channels. We also found elevated compressive strains near the interface between the compound contact and the NW and relatively lower strains near the center of the channel which increased exponentially below the 10 nm channel length to exceed 10% strain at ~3 nm lengths. These compressive strains are expected to result in a non-homogeneous energy band structure in Ge/Si core/shell NWs below 10 nm and potentially benefit their transistor performance.« less

In situ control of synchronous germanide/silicide reactions with Ge/Si core/shell nanowires to monitor formation and strain evolution in abrupt 2.7 nm channel length

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Renjie; Nguyen, Binh-Minh; Tang, Wei

The metal-semiconductor interface in self-aligned contact formation can determine the overall performance of nanoscale devices. This interfacial morphology is predicted and well researched in homogenous semiconductor nanowires (NWs) but was not pursued in heterostructured core/shell nanowires. Here, we found here that the solid-state reactions between Ni and Ge/Si core/shell nanowires resulted in a protruded and a leading NiSiy segment into the channel. A single Ni 2Ge/NiSi y to Ge/Si core/shell interface was achieved by the selective shell removal near the Ni source/drain contact areas. In using in situ transmission electron microscopy, we measured the growth rate and anisotropic strain evolutionmore » in ultra-short channels. We also found elevated compressive strains near the interface between the compound contact and the NW and relatively lower strains near the center of the channel which increased exponentially below the 10 nm channel length to exceed 10% strain at ~3 nm lengths. These compressive strains are expected to result in a non-homogeneous energy band structure in Ge/Si core/shell NWs below 10 nm and potentially benefit their transistor performance.« less

Performance of Ultra Wideband On-Body Communication Based on Statistical Channel Model

NASA Astrophysics Data System (ADS)

Wang, Qiong; Wang, Jianqing

Ultra wideband (UWB) on-body communication is attracting much attention in biomedical applications. In this paper, the performance of UWB on-body communication is investigated based on a statistically extracted on-body channel model, which provides detailed characteristics of the multi-path-affected channel with an emphasis on various body postures or body movement. The possible data rate, the possible communication distance, as well as the bit error rate (BER) performance are clarified via computer simulation. It is found that the conventional correlation receiver is incompetent in the multi-path-affected on-body channel, while the RAKE receiver outperforms the conventional correlation receiver at a cost of structure complexity. Different RAKE receiver structures are compared to show the improvement of the BER performance.

Parametric Evaluation of an Innovative Ultra-Violet PhotocatalyticOxidation (UVPCO) Air Cleaning Technology for Indoor Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hodgson, Alfred T.; Sullivan, Douglas P.; Fisk, William J.

2005-10-31

An innovative Ultra-Violet Photocatalytic Oxidation (UVPCO) air cleaning technology employing a semitransparent catalyst coated on a semitransparent polymer substrate was evaluated to determine its effectiveness for treating mixtures of volatile organic compounds (VOCs) representative of indoor environments at low, indoor-relevant concentration levels. The experimental UVPCO contained four 30 by 30-cm honeycomb monoliths irradiated with nine UVA lamps arranged in three banks. A parametric evaluation of the effects of monolith thickness, air flow rate through the device, UV power, and reactant concentrations in inlet air was conducted for the purpose of suggesting design improvements. The UVPCO was challenged with three mixturesmore » of VOCs. A synthetic office mixture contained 27 VOCs commonly measured in office buildings. A building product mixture was created by combining sources including painted wallboard, composite wood products, carpet systems, and vinyl flooring. The third mixture contained formaldehyde and acetaldehyde. Steady state concentrations were produced in a classroom laboratory or a 20-m{sup 3} chamber. Air was drawn through the UVPCO, and single-pass conversion efficiencies were measured from replicate samples collected upstream and downstream of the reactor. Thirteen experiments were conducted in total. In this UVPCO employing a semitransparent monolith design, an increase in monolith thickness is expected to result in general increases in both reaction efficiencies and absolute reaction rates for VOCs oxidized by photocatalysis. The thickness of individual monolith panels was varied between 1.2 and 5 cm (5 to 20 cm total thickness) in experiments with the office mixture. VOC reaction efficiencies and rates increased with monolith thickness. However, the analysis of the relationship was confounded by high reaction efficiencies in all configurations for a number of compounds. These reaction efficiencies approached or exceeded 90% for alcohols, glycol ethers, and other individual compounds including d-limonene, 1,2,4-trimethylbenzene, and decamethylcyclopentasiloxane. This result implies a reaction efficiency of about 30% per irradiated monolith face, which is in agreement with the maximum efficiency for the system predicted with a simulation model. In these and other experiments, the performance of the system for highly reactive VOCs appeared to be limited by mass transport of reactants to the catalyst surface rather than by photocatalytic activity. Increasing the air flow rate through the UVPCO device decreases the residence time of the air in the monoliths and improves mass transfer to the catalyst surface. The effect of gas velocity was examined in four pairs of experiments in which the air flow rate was varied from approximately 175 m{sup 3}/h to either 300 or 600 m{sup 3}/h. Increased gas velocity caused a decrease in reaction efficiency for nearly all reactive VOCs. For all of the more reactive VOCs, the decrease in performance was less, and often substantially less, than predicted based solely on residence time, again likely due to mass transfer limitations at the low flow rate. The results demonstrate that the UVPCO is capable of achieving high conversion efficiencies for reactive VOCs at air flow rates above the base experimental rate of 175 m{sup 3}/h. The effect of UV power was examined in a series of experiments with the building product mixture in which the number of lamps was varied between nine and three. For the most reactive VOCs in the mixture, the effects of UV power were surprisingly small. Thus, even with only one lamp in each section, there appears to be sufficient photocatalytic activity to decompose most of the mass of reactive VOCs that reach the catalyst surface. For some less reactive VOCs, the trend of decreasing efficiency with decreasing UV intensity was in general agreement with simulation model predictions.« less

In-situ Testing of the EHT High Gain and Frequency Ultra-Stable Integrators

NASA Astrophysics Data System (ADS)

Miller, Kenneth; Ziemba, Timothy; Prager, James; Slobodov, Ilia; Lotz, Dan

2014-10-01

Eagle Harbor Technologies (EHT) has developed a long-pulse integrator that exceeds the ITER specification for integration error and pulse duration. During the Phase I program, EHT improved the RPPL short-pulse integrators, added a fast digital reset, and demonstrated that the new integrators exceed the ITER integration error and pulse duration requirements. In Phase II, EHT developed Field Programmable Gate Array (FPGA) software that allows for integrator control and real-time signal digitization and processing. In the second year of Phase II, the EHT integrator will be tested at a validation platform experiment (HIT-SI) and tokamak (DIII-D). In the Phase IIB program, EHT will continue development of the EHT integrator to reduce overall cost per channel. EHT will test lower cost components, move to surface mount components, and add an onboard Field Programmable Gate Array and data acquisition to produce a stand-alone system with lower cost per channel and increased the channel density. EHT will test the Phase IIB integrator at a validation platform experiment (HIT-SI) and tokamak (DIII-D). Work supported by the DOE under Contract Number (DE-SC0006281).

Deep-submicron Graphene Field-Effect Transistors with State-of-Art fmax

PubMed Central

Lyu, Hongming; Lu, Qi; Liu, Jinbiao; Wu, Xiaoming; Zhang, Jinyu; Li, Junfeng; Niu, Jiebin; Yu, Zhiping; Wu, Huaqiang; Qian, He

2016-01-01

In order to conquer the short-channel effects that limit conventional ultra-scale semiconductor devices, two-dimensional materials, as an option of ultimate thin channels, receive wide attention. Graphene, in particular, bears great expectations because of its supreme carrier mobility and saturation velocity. However, its main disadvantage, the lack of bandgap, has not been satisfactorily solved. As a result, maximum oscillation frequency (fmax) which indicates transistors’ power amplification ability has been disappointing. Here, we present submicron field-effect transistors with specially designed low-resistance gate and excellent source/drain contact, and therefore significantly improved fmax. The fabrication was assisted by the advanced 8-inch CMOS back-end-of-line technology. A 200-nm-gate-length GFET achieves fT/fmax = 35.4/50 GHz. All GFET samples with gate lengths ranging from 200 nm to 400 nm possess fmax 31–41% higher than fT, closely resembling Si n-channel MOSFETs at comparable technology nodes. These results re-strengthen the promise of graphene field-effect transistors in next generation semiconductor electronics. PMID:27775009

Ultra-short pulse laser micro patterning with highest throughput by utilization of a novel multi-beam processing head

NASA Astrophysics Data System (ADS)

Homburg, Oliver; Jarczynski, Manfred; Mitra, Thomas; Brüning, Stephan

2017-02-01

In the last decade much improvement has been achieved for ultra-short pulse lasers with high repetition rates. This laser technology has vastly matured so that it entered a manifold of industrial applications recently compared to mainly scientific use in the past. Compared to ns-pulse ablation ultra-short pulses in the ps- or even fs regime lead to still colder ablation and further reduced heat-affected zones. This is crucial for micro patterning when structure sizes are getting smaller and requirements are getting stronger at the same time. An additional advantage of ultra-fast processing is its applicability to a large variety of materials, e.g. metals and several high bandgap materials like glass and ceramics. One challenge for ultra-fast micro machining is throughput. The operational capacity of these processes can be maximized by increasing the scan rate or the number of beams - parallel processing. This contribution focuses on process parallelism of ultra-short pulsed lasers with high repetition rate and individually addressable acousto-optical beam modulation. The core of the multi-beam generation is a smooth diffractive beam splitter component with high uniform spots and negligible loss, and a prismatic array compressor to match beam size and pitch. The optical design and the practical realization of an 8 beam processing head in combination with a high average power single mode ultra-short pulsed laser source are presented as well as the currently on-going and promising laboratory research and micro machining results. Finally, an outlook of scaling the processing head to several tens of beams is given.

Polymer enabled 100 Gbaud connectivity for datacom applications

NASA Astrophysics Data System (ADS)

Katopodis, V.; Groumas, P.; Zhang, Z.; Dinu, R.; Miller, E.; Konczykowska, A.; Dupuy, J.-Y.; Beretta, A.; Dede, A.; Choi, J. H.; Harati, P.; Jorge, F.; Nodjiadjim, V.; Riet, Muriel; Cangini, G.; Vannucci, A.; Keil, N.; Bach, H.-G.; Grote, N.; Avramopoulos, H.; Kouloumentas, Ch.

2016-03-01

Polymers hold the promise for ultra-fast modulation of optical signals due to their potential for ultra-fast electro-optic (EO) response and high EO coefficient. In this work, we present the basic structure and properties of an efficient EO material system, and we summarize the efforts made within the project ICT-POLYSYS for the development of high-speed transmitters based on this system. More specifically, we describe successful efforts for the monolithic integration of multi-mode interference (MMI) couplers and Bragg-gratings (BGs) along with Mach-Zehnder modulators (MZMs) on this platform, and for the hybrid integration of InP active elements in the form of laser diodes (LDs) and gain chips (GCs). Using these integration techniques and the combination of the hybrid optical chips with ultra-fast indium phosphide double heterojunction bipolar transistor (InP-DHBT) electronics, we develop and fully package a single 100 Gb/s transmitter and a 2×100 Gb/s transmitter that can support serial operation at this rate with conventional non-return-to-zero on-off-keying (NRZ-OOK) modulation format. We also present the experimental evaluation of the devices, validating the efficiency of the monolithic and hybrid integration concepts and confirming the potential of this technology for single-lane 100 Gb/s optical connectivity in data-center network environments. Results from transmission experiments to this end include the achievement of BER close to 6·10-9 in B2B configuration, the achievement of BER lower than 10-7 for propagation over standard single-mode fiber (SSMF) with total length up to 1000 m, and the achievement of BER at the level of 10-5 after 1625 m of SSMF. Finally, plans for the use of the EO polymer system in a more complex hybrid integration platform for high-flexibility/high-capacity transmitters are also outlined.

Ensuring repeatability and robustness of poly(glycidyl methacrylate-co-ethylene dimethacrylate) HPLC monolithic columns of 3 mm id through covalent bonding to the column wall.

PubMed

Laaniste, Asko; Kruve, Anneli; Leito, Ivo

2013-08-01

Two different methods to reinforce the poly(glycidyl methacrylate-co-ethylene dimethacrylate) HPLC monolithic columns of 3 mm id in a glass column reservoir were studied: composite columns with polymeric particles in the monolith and surface treatment of the reservoir wall. Of the two methods used to counter the mechanical instability and formation of flow channels (composite columns and column wall surface treatment), we demonstrated that proper column wall surface treatment was sufficient to solve both problems. Our study also indicated that no surface treatment is efficient, and of the methods studied silanization in acidified ethanol solution and constant renewal of the reaction mixture (dynamic mode) proved to be the most effective. As a result of this study, we have been able to prepare repeatable and durable methacrylate HPLC columns with good efficiencies. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Full-wafer fabrication by nanostencil lithography of micro/nanomechanical mass sensors monolithically integrated with CMOS.

PubMed

Arcamone, J; van den Boogaart, M A F; Serra-Graells, F; Fraxedas, J; Brugger, J; Pérez-Murano, F

2008-07-30

Wafer-scale nanostencil lithography (nSL) is used to define several types of silicon mechanical resonators, whose dimensions range from 20 µm down to 200 nm, monolithically integrated with CMOS circuits. We demonstrate the simultaneous patterning by nSL of ∼2000 nanodevices per wafer by post-processing standard CMOS substrates using one single metal evaporation, pattern transfer to silicon and subsequent etch of the sacrificial layer. Resonance frequencies in the MHz range were measured in air and vacuum. As proof-of-concept towards an application as high performance sensors, CMOS integrated nano/micromechanical resonators are successfully implemented as ultra-sensitive areal mass sensors. These devices demonstrate the ability to monitor the deposition of gold layers whose average thickness is smaller than a monolayer. Their areal mass sensitivity is in the range of 10(-11) g cm(-2) Hz(-1), and their thickness resolution corresponds to approximately a thousandth of a monolayer.

Prospect of Thermal Insulation by Silica Aerogel: A Brief Review

NASA Astrophysics Data System (ADS)

Hasan, Mohammed Adnan; Sangashetty, Rashmi; Esther, A. Carmel Mary; Patil, Sharanabasappa B.; Sherikar, Baburao N.; Dey, Arjun

2017-10-01

Silica aerogel is a unique ultra light weight nano porous material which offers superior thermal insulation property as compared to the conventional thermal insulating materials. It can be applied not only for ground and aerospace applications but also in low and high temperatures and pressure regimes. Aerogel granules and monolith are synthesized by the sol-gel route while aerogel based composites are fabricated by the reinforcement of fibers, particle and opacifiers. Due to the characteristic brittleness (i.e., poor mechanical properties) of monolith or bulk aerogel, it is restricted in several applications. To improve the mechanical integrity and flexibility, usually different fibers are reinforced with aerogel and hence it can be used as flexible thermal insulation blankets. Further, to achieve effective thermal insulation behaviour particularly at high temperature, often opacifiers are doped with silica aerogel. In the present brief review, the prospects of bulk aerogel and aerogel based composites are discussed for the application of thermal insulation and thermal stability.

Solid oxide fuel cell with monolithic core

DOEpatents

McPheeters, Charles C.; Mrazek, Franklin C.

1988-01-01

A solid oxide fuel cell in which fuel and oxidant gases undergo an electrochemical reaction to produce an electrical output includes a monolithic core comprised of a corrugated conductive sheet disposed between upper and lower generally flat sheets. The corrugated sheet includes a plurality of spaced, parallel, elongated slots which form a series of closed, linear, first upper and second lower gas flow channels with the upper and lower sheets within which a fuel gas and an oxidant gas respectively flow. Facing ends of the fuel cell are generally V-shaped and provide for fuel and oxidant gas inlet and outlet flow, respectively, and include inlet and outlet gas flow channels which are continuous with the aforementioned upper fuel gas and lower oxidant gas flow channels. The upper and lower flat sheets and the intermediate corrugated sheet are preferably comprised of ceramic materials and are securely coupled together such as by assembly in the green state and sintering together during firing at high temperatures. A potential difference across the fuel cell, or across a stacked array of similar fuel cells, is generated when an oxidant gas such as air and a fuel such as hydrogen gas is directed through the fuel cell at high temperatures, e.g., between 700.degree. C. and 1100.degree. C.

Solid oxide fuel cell with monolithic core

DOEpatents

McPheeters, C.C.; Mrazek, F.C.

1988-08-02

A solid oxide fuel cell in which fuel and oxidant gases undergo an electrochemical reaction to produce an electrical output includes a monolithic core comprised of a corrugated conductive sheet disposed between upper and lower generally flat sheets. The corrugated sheet includes a plurality of spaced, parallel, elongated slots which form a series of closed, linear, first upper and second lower gas flow channels with the upper and lower sheets within which a fuel gas and an oxidant gas respectively flow. Facing ends of the fuel cell are generally V-shaped and provide for fuel and oxidant gas inlet and outlet flow, respectively, and include inlet and outlet gas flow channels which are continuous with the aforementioned upper fuel gas and lower oxidant gas flow channels. The upper and lower flat sheets and the intermediate corrugated sheet are preferably comprised of ceramic materials and are securely coupled together such as by assembly in the green state and sintering together during firing at high temperatures. A potential difference across the fuel cell, or across a stacked array of similar fuel cells, is generated when an oxidant gas such as air and a fuel such as hydrogen gas is directed through the fuel cell at high temperatures, e.g., between 700 C and 1,100 C. 8 figs.

Nanoporous carbon tunable resistor/transistor and methods of production thereof

DOEpatents

Biener, Juergen; Baumann, Theodore F; Dasgupta, Subho; Hahn, Horst

2014-04-22

In one embodiment, a tunable resistor/transistor includes a porous material that is electrically coupled between a source electrode and a drain electrode, wherein the porous material acts as an active channel, an electrolyte solution saturating the active channel, the electrolyte solution being adapted for altering an electrical resistance of the active channel based on an applied electrochemical potential, wherein the active channel comprises nanoporous carbon arranged in a three-dimensional structure. In another embodiment, a method for forming the tunable resistor/transistor includes forming a source electrode, forming a drain electrode, and forming a monolithic nanoporous carbon material that acts as an active channel and selectively couples the source electrode to the drain electrode electrically. In any embodiment, the electrolyte solution saturating the nanoporous carbon active channel is adapted for altering an electrical resistance of the nanoporous carbon active channel based on an applied electrochemical potential.

Lower periprosthetic bone loss and good fixation of an ultra-short stem compared to a conventional stem in uncemented total hip arthroplasty.

PubMed

Salemyr, Mats; Muren, Olle; Ahl, Torbjörn; Bodén, Henrik; Eisler, Thomas; Stark, André; Sköldenberg, Olof

2015-01-01

We hypothesized that an ultra-short stem would load the proximal femur in a more physiological way and could therefore reduce the adaptive periprosthetic bone loss known as stress shielding. 51 patients with primary hip osteoarthritis were randomized to total hip arthroplasty (THA) with either an ultra-short stem or a conventional tapered stem. The primary endpoint was change in periprosthetic bone mineral density (BMD), measured with dual-energy x-ray absorptiometry (DXA), in Gruen zones 1 and 7, two years after surgery. Secondary endpoints were change in periprosthetic BMD in the entire periprosthetic region, i.e. Gruen zones 1 through 7, stem migration measured with radiostereometric analysis (RSA), and function measured with self-administered functional scores. The periprosthetic decrease in BMD was statistically significantly lower with the ultra-short stem. In Gruen zone 1, the mean difference was 18% (95% CI: -27% to -10%). In zone 7, the difference was 5% (CI: -12% to -3%) and for Gruen zones 1-7 the difference was also 5% (CI: -9% to -2%). During the first 6 weeks postoperatively, the ultra-short stems migrated 0.77 mm more on average than the conventional stems. 3 months after surgery, no further migration was seen. The functional scores improved during the study and were similar in the 2 groups. Up to 2 years after total hip arthroplasty, compared to the conventional tapered stem the ultra-short uncemented anatomical stem induced lower periprosthetic bone loss and had equally excellent stem fixation and clinical outcome.

Detailed surface reaction mechanism in a three-way catalyst.

PubMed

Chatterjee, D; Deutschmann, O; Warnatz, J

2001-01-01

Monolithic three-way catalysts are applied to reduce the emission of combustion engines. The design of such a catalytic converter is a complex process involving the optimization of different physical and chemical parameters (in the simplest case, e.g., length, cell densities or metal coverage of the catalyst). Numerical simulation can be used as an effective tool for the investigation of the catalytic properties of a catalytic converter and for the prediction of the performance of the catalyst. To attain this goal, a two-dimensional flow-field description is coupled with a detailed surface reaction model (gas-phase reactions can be neglected in three-way catalysts). This surface reaction mechanism (with C3H6 taken as representative of unburnt hydrocarbons) was developed using sub-mechanisms recently developed for hydrogen, carbon monoxide and methane oxidation, literature values for C3H6 oxidation, and estimates for the remaining unknown reactions. Results of the simulation of a monolithic single channel are used to validate the surface reaction mechanism. The performance of the catalyst was simulated under lean, nearly stoichiometric and rich conditions. For these characteristic conditions, the oxidation of propene and carbon monoxide and the reduction of NO on a typical Pt/Rh coated three-way catalyst were simulated as a function of temperature. The numerically predicted conversion data are compared with experimentally measured data. The simulation further reveals the coupling between chemical reactions and transport processes within the monolithic channel.

3D printed titanium micro-bore columns containing polymer monoliths for reversed-phase liquid chromatography.

PubMed

Gupta, Vipul; Talebi, Mohammad; Deverell, Jeremy; Sandron, Sara; Nesterenko, Pavel N; Heery, Brendan; Thompson, Fletcher; Beirne, Stephen; Wallace, Gordon G; Paull, Brett

2016-03-03

The potential of 3D selective laser melting (SLM) technology to produce compact, temperature and pressure stable titanium alloy chromatographic columns is explored. A micro bore channel (0.9 mm I.D. × 600 mm long) was produced within a 5 × 30 × 30 mm titanium alloy (Ti-6Al-4V) cuboid, in form of a double handed spiral. A poly(butyl methacrylate-co-ethyleneglycoldimethacrylate) (BuMA-co-EDMA) monolithic stationary phase was thermally polymerised within the channel for application in reversed-phase high-performance liquid chromatography. The prepared monolithic column was applied to the liquid chromatographic separation of intact proteins and peptides. Peak capacities of 69-76 (for 6-8 proteins respectively) were observed during isothermal separation of proteins at 44 °C which were further increased to 73-77 using a thermal step gradient with programmed temperature from 60 °C to 35 °C using an in-house built direct-contact heater/cooler platform based upon matching sized Peltier thermoelectric modules. Rapid temperature gradients were possible due to direct-contact between the planar metal column and the Peltier module, and the high thermal conductivity of the titanium column as compared to a similar stainless steel printed column. The separation of peptides released from a digestion of E.coli was also achieved in less than 35 min with ca. 40 distinguishable peaks at 210 nm. Copyright © 2016 Elsevier B.V. All rights reserved.

Ultra-Low Loss Waveguides with Application to Photonic Integrated Circuits

NASA Astrophysics Data System (ADS)

Bauters, Jared F.

The integration of photonic components using a planar platform promises advantages in cost, size, weight, and power consumption for optoelectronic systems. Yet, the typical propagation loss of 5-10 dB/m in a planar silica waveguide is nearly five orders-of-magnitude larger than that in low loss optical fibers. For some applications, the miniaturization of the photonic system and resulting smaller propagation lengths from integration are enough to overcome the increase in propagation loss. For other more demanding systems or applications, such as those requiring long optical time delays or high-quality-factor (Q factor) resonators, the high propagation loss can degrade system performance to a degree that trumps the potential advantages offered by integration. Thus, the reduction of planar waveguide propagation loss in a Si3-N4 based waveguide platform is a primary focus of this dissertation. The ultra-low loss stoichiometric Si3-N4 waveguide platform offers the additional advantages of fabrication process stability and repeatability. Yet, active devices such as lasers, amplifiers, and photodetectors have not been monolithically integrated with ultra-low loss waveguides due to the incompatibility of the active and ultra-low loss processing thermal budgets (ultra-low loss waveguides are annealed at temperatures exceeding 1000 °C in order to drive out impurities). So a platform that enables the integration of active devices with the ultra-low losses of the Si3- N4 waveguide platform is this dissertation's second focus. The work enables the future fabrication of sensor, gyroscope, true time delay, and low phase noise oscillator photonic integrated circuits.

Affinity chromatography on monolithic supports for simultaneous and high-throughput isolation of immunoglobulins from human serum.

PubMed

Martinović, Tamara; Andjelković, Uroš; Klobučar, Marko; Černigoj, Urh; Vidič, Jana; Lučić, Marina; Pavelić, Krešimir; Josić, Djuro

2017-11-01

Posttranslational modifications of immunoglobulins have been a topic of great interest and have been repeatedly reported as a major factor in disease pathology. Cost-effective, reproducible, and high-throughput (HTP) isolation of immunoglobulins from human serum is vital for studying the changes in protein structure and the following understanding of disease development. Although there are many methods for the isolation of specific immunoglobulin classes, only a few of them are applicable for isolation of all subtypes and variants. Here, we present the development of a scheme for fast and simultaneous affinity purification of α (A), γ (G), and μ (M) immunoglobulins from human serum through affinity monolith chromatography. Affinity-based monolithic columns with immobilized protein A, G, or L were used for antibody isolation. Monolithic stationary phases have a high surface accessibility of binding sites, large flow-through channels, and can be operated at high flow rates, making them the ideal supports for HTP isolation of biopolymers. The presented method can be used for HTP screening of human serum in order to simultaneously isolate all three above-mentioned immunoglobulins and determine their concentration and changes in their glycosylation pattern as potential prognostic and diagnostic disease biomarkers. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

VCSEL technologies and applications

NASA Astrophysics Data System (ADS)

Steinle, Gunther; Ramakrishnan, A.; Supper, D.; Kristen, Guenter; Pfeiffer, J.; Degen, Ch.; Riechert, Henning; Ebbinghaus, G.; Wolf, H. D.

2002-07-01

VCSEL devices for 850nm and 1300nm emission wavelength are presented, suitable for operation in single-channel interconnects as well as parallel optical links. Necessary properties for applications such as 10 Gigabit Ethernet and actual limits for the use of VCSELs are discussed in some detail. Recent progress is demonstrated in developing devices with production-friendly diameters larger than 5´m for 10Gbit/s operation. Also devices with a temperature insensitive monolithically integrated monitordiode are presented and discussed. In order to reach the emission wavelength of 1300nm with a GaAs-based monolithic VCSEL-structure, we use GaInNxAs1-x quantum-wells with a small nitrogen concentration x between one and two percent. We have two different growth approaches, such as solid source MBE with a rf-plasma source to produce reactive nitrogen from nitrogen gas N2 and MOCVD with unsymmetrical di-methylhydrazine as a precursor for nitrogen. The long-wavelength devices comprise intracavity contacts in order to reduce absorption losses due to doped layers. Bitrates up to 10Gbit/s per channel can be achieved within both wavelength regimes.

EML Array fabricated by SAG technique monolithically integrated with a buried ridge AWG multiplexer

NASA Astrophysics Data System (ADS)

Xu, Junjie; Liang, Song; Zhang, Zhike; An, Junming; Zhu, Hongliang; Wang, Wei

2017-06-01

We report the fabrication of a ten channel electroabsorption modulated DFB laser (EML) array. Different emission wavelengths of the laser array are obtained by selective area growth (SAG) technique, which is also used for the integration of electroabsorption modulators (EAM) with the lasers. An arrayed waveguide grating (AWG) combiner is integrated monolithically with the laser array by butt-joint regrowth (BJR) technique. A buried ridge waveguide structure is adopted for the AWG combiner. A self aligned fabrication procedure is adopted for the fabrication of the waveguide structure of the device to eliminate the misalignment between the laser active waveguide and the passive waveguide. A Ti thin film heater is integrated for each laser in the array. With the help of the heaters, ten laser emissions with 1.8 nm channel spacing are obtained. The integrated EAM has a larger than 11 dB static extinction ratios and larger than 8 GHz small signal modulation bandwidths. The light power collected in the output waveguide of the AWG is larger than -13 dBm for each wavelength.

CMOS-compatible InP/InGaAs digital photoreceiver

DOEpatents

Lovejoy, Michael L.; Rose, Benny H.; Craft, David C.; Enquist, Paul M.; Slater, Jr., David B.

1997-01-01

A digital photoreceiver is formed monolithically on an InP semiconductor substrate and comprises a p-i-n photodetector formed from a plurality of InP/InGaAs layers deposited by an epitaxial growth process and an adjacent heterojunction bipolar transistor (HBT) amplifier formed from the same InP/InGaAs layers. The photoreceiver amplifier operates in a large-signal mode to convert a detected photocurrent signal into an amplified output capable of directly driving integrated circuits such as CMOS. In combination with an optical transmitter, the photoreceiver may be used to establish a short-range channel of digital optical communications between integrated circuits with applications to multi-chip modules (MCMs). The photoreceiver may also be used with fiber optic coupling for establishing longer-range digital communications (i.e. optical interconnects) between distributed computers or the like. Arrays of digital photoreceivers may be formed on a common substrate for establishing a plurality of channels of digital optical communication, with each photoreceiver being spaced by less than about 1 mm and consuming less than about 20 mW of power, and preferably less than about 10 mW. Such photoreceiver arrays are useful for transferring huge amounts of digital data between integrated circuits at bit rates of up to about 1000 Mb/s or more.

CMOS-compatible InP/InGaAs digital photoreceiver

DOEpatents

Lovejoy, M.L.; Rose, B.H.; Craft, D.C.; Enquist, P.M.; Slater, D.B. Jr.

1997-11-04

A digital photoreceiver is formed monolithically on an InP semiconductor substrate and comprises a p-i-n photodetector formed from a plurality of InP/InGaAs layers deposited by an epitaxial growth process and an adjacent heterojunction bipolar transistor (HBT) amplifier formed from the same InP/InGaAs layers. The photoreceiver amplifier operates in a large-signal mode to convert a detected photocurrent signal into an amplified output capable of directly driving integrated circuits such as CMOS. In combination with an optical transmitter, the photoreceiver may be used to establish a short-range channel of digital optical communications between integrated circuits with applications to multi-chip modules (MCMs). The photoreceiver may also be used with fiber optic coupling for establishing longer-range digital communications (i.e. optical interconnects) between distributed computers or the like. Arrays of digital photoreceivers may be formed on a common substrate for establishing a plurality of channels of digital optical communication, with each photoreceiver being spaced by less than about 1 mm and consuming less than about 20 mW of power, and preferably less than about 10 mW. Such photoreceiver arrays are useful for transferring huge amounts of digital data between integrated circuits at bit rates of up to about 1,000 Mb/s or more. 4 figs.

Detachable strong cation exchange monolith, integrated with capillary zone electrophoresis and coupled with pH gradient elution, produces improved sensitivity and numbers of peptide identifications during bottom-up analysis of complex proteomes.

PubMed

Zhang, Zhenbin; Yan, Xiaojing; Sun, Liangliang; Zhu, Guijie; Dovichi, Norman J

2015-04-21

A detachable sulfonate-silica hybrid strong cation-exchange monolith was synthesized in a fused silica capillary, and used for solid phase extraction with online pH gradient elution during capillary zone electrophoresis-tandem mass spectrometry (CZE-MS/MS) proteomic analysis. Tryptic digests were prepared in 50 mM formic acid and loaded onto the strong cation-exchange monolith. Fractions were eluted using a series of buffers with lower concentration but higher pH values than the 50 mM formic acid background electrolyte. This combination of elution and background electrolytes results in both sample stacking and formation of a dynamic pH junction and allows use of relatively large elution buffer volumes while maintaining reasonable peak efficiency and resolution. A series of five pH bumps were applied to elute E. coli tryptic peptides from the monolith, followed by analysis using CZE coupled to an LTQ-Orbitrap Velos mass spectrometer; 799 protein groups and 3381 peptides were identified from 50 ng of the digest in a 2.5 h analysis, which approaches the identification rate for this organism that was obtained with an Orbitrap Fusion. We attribute the improved numbers of peptide and protein identifications to the efficient fractionation by the online pH gradient elution, which decreased the complexity of the sample in each elution step and improved the signal intensity of low abundance peptides. We also performed a comparative analysis using a nanoACQUITY UltraPerformance LCH system. Similar numbers of protein and peptide identifications were produced by the two methods. Protein identifications showed significant overlap between the two methods, whereas peptide identifications were complementary.

Adequacy of the Ultra-Short-Term HRV to Assess Adaptive Processes in Youth Female Basketball Players.

PubMed

Nakamura, Fabio Y; Pereira, Lucas A; Cal Abad, Cesar C; Cruz, Igor F; Flatt, Andrew A; Esco, Michael R; Loturco, Irineu

2017-02-01

Heart rate variability has been widely used to monitor athletes' cardiac autonomic control changes induced by training and competition, and recently shorter recording times have been sought to improve its practicality. The aim of this study was to test the agreement between the (ultra-short-term) natural log of the root-mean-square difference of successive normal RR intervals (lnRMSSD - measured in only 1 min post-1 min stabilization) and the criterion lnRMSSD (measured in the last 5 min out of 10 min of recording) in young female basketball players. Furthermore, the correlation between training induced delta change in the ultra-short-term lnRMSSD and the criterion lnRMSSD was calculated. Seventeen players were assessed at rest pre- and post-eight weeks of training. Trivial effect sizes (-0.03 in the pre- and 0.10 in the post- treatment) were found in the comparison between the ultra-short-term lnRMSSD (3.29 ± 0.45 and 3.49 ± 0.35 ms, in the pre- and post-, respectively) and the criterion lnRMSSD (3.30 ± 0.40 and 3.45 ± 0.41 ms, in the pre- and post-, respectively) (intraclass correlation coefficient = 0.95 and 0.93). In both cases, the response to training was significant, with Pearson's correlation of 0.82 between the delta changes of the ultra-short-term lnRMSSD and the criterion lnRMSSD. In conclusion, the lnRMSSD can be calculated within only 2 min of data acquisition (the 1 st min discarded) in young female basketball players, with the ultra-short-term measure presenting similar sensitivity to training effects as the standard criterion measure.

Lower periprosthetic bone loss and good fixation of an ultra-short stem compared to a conventional stem in uncemented total hip arthroplasty

PubMed Central

Salemyr, Mats; Muren, Olle; Ahl, Torbjörn; Bodén, Henrik; Eisler, Thomas; Stark, André; Sköldenberg, Olof

2015-01-01

Background and purpose — We hypothesized that an ultra-short stem would load the proximal femur in a more physiological way and could therefore reduce the adaptive periprosthetic bone loss known as stress shielding. Patients and methods — 51 patients with primary hip osteoarthritis were randomized to total hip arthroplasty (THA) with either an ultra-short stem or a conventional tapered stem. The primary endpoint was change in periprosthetic bone mineral density (BMD), measured with dual-energy x-ray absorptiometry (DXA), in Gruen zones 1 and 7, two years after surgery. Secondary endpoints were change in periprosthetic BMD in the entire periprosthetic region, i.e. Gruen zones 1 through 7, stem migration measured with radiostereometric analysis (RSA), and function measured with self-administered functional scores. Results — The periprosthetic decrease in BMD was statistically significantly lower with the ultra-short stem. In Gruen zone 1, the mean difference was 18% (95% CI: −27% to −10%). In zone 7, the difference was 5% (CI: −12% to −3%) and for Gruen zones 1–7 the difference was also 5% (CI: −9% to −2%). During the first 6 weeks postoperatively, the ultra-short stems migrated 0.77 mm more on average than the conventional stems. 3 months after surgery, no further migration was seen. The functional scores improved during the study and were similar in the 2 groups. Interpretation — Up to 2 years after total hip arthroplasty, compared to the conventional tapered stem the ultra-short uncemented anatomical stem induced lower periprosthetic bone loss and had equally excellent stem fixation and clinical outcome. PMID:26134386

Adequacy of the Ultra-Short-Term HRV to Assess Adaptive Processes in Youth Female Basketball Players

PubMed Central

Nakamura, Fabio Y; Pereira, Lucas A; Cal Abad, Cesar C; Cruz, Igor F; Flatt, Andrew A; Esco, Michael R; Loturco, Irineu

2017-01-01

Abstract Heart rate variability has been widely used to monitor athletes’ cardiac autonomic control changes induced by training and competition, and recently shorter recording times have been sought to improve its practicality. The aim of this study was to test the agreement between the (ultra-short-term) natural log of the root-mean-square difference of successive normal RR intervals (lnRMSSD - measured in only 1 min post-1 min stabilization) and the criterion lnRMSSD (measured in the last 5 min out of 10 min of recording) in young female basketball players. Furthermore, the correlation between training induced delta change in the ultra-short-term lnRMSSD and the criterion lnRMSSD was calculated. Seventeen players were assessed at rest pre- and post-eight weeks of training. Trivial effect sizes (-0.03 in the pre- and 0.10 in the post- treatment) were found in the comparison between the ultra-short-term lnRMSSD (3.29 ± 0.45 and 3.49 ± 0.35 ms, in the pre- and post-, respectively) and the criterion lnRMSSD (3.30 ± 0.40 and 3.45 ± 0.41 ms, in the pre- and post-, respectively) (intraclass correlation coefficient = 0.95 and 0.93). In both cases, the response to training was significant, with Pearson’s correlation of 0.82 between the delta changes of the ultra-short-term lnRMSSD and the criterion lnRMSSD. In conclusion, the lnRMSSD can be calculated within only 2 min of data acquisition (the 1st min discarded) in young female basketball players, with the ultra-short-term measure presenting similar sensitivity to training effects as the standard criterion measure. PMID:28469745

An ultra-stable voltage source for precision Penning-trap experiments

NASA Astrophysics Data System (ADS)

Böhm, Ch.; Sturm, S.; Rischka, A.; Dörr, A.; Eliseev, S.; Goncharov, M.; Höcker, M.; Ketter, J.; Köhler, F.; Marschall, D.; Martin, J.; Obieglo, D.; Repp, J.; Roux, C.; Schüssler, R. X.; Steigleder, M.; Streubel, S.; Wagner, Th.; Westermann, J.; Wieder, V.; Zirpel, R.; Melcher, J.; Blaum, K.

2016-08-01

An ultra-stable and low-noise 25-channel voltage source providing 0 to -100 V has been developed. It will supply stable bias potentials for Penning-trap electrodes used in high-precision experiments. The voltage source generates all its supply voltages via a specially designed transformer. Each channel can be operated either in a precision mode or can be dynamically ramped. A reference module provides reference voltages for all the channels, each of which includes a low-noise amplifier to gain a factor of 10 in the output stage. A relative voltage stability of δV / V ≈ 2 ×10-8 has been demonstrated at -89 V within about 10 min.

Free space optical ultra-wideband communications over atmospheric turbulence channels.

PubMed

Davaslioğlu, Kemal; Cağiral, Erman; Koca, Mutlu

2010-08-02

A hybrid impulse radio ultra-wideband (IR-UWB) communication system in which UWB pulses are transmitted over long distances through free space optical (FSO) links is proposed. FSO channels are characterized by random fluctuations in the received light intensity mainly due to the atmospheric turbulence. For this reason, theoretical detection error probability analysis is presented for the proposed system for a time-hopping pulse-position modulated (TH-PPM) UWB signal model under weak, moderate and strong turbulence conditions. For the optical system output distributed over radio frequency UWB channels, composite error analysis is also presented. The theoretical derivations are verified via simulation results, which indicate a computationally and spectrally efficient UWB-over-FSO system.

In Situ Formation of Polysulfonamide Supported Poly(ethylene glycol) Divinyl Ether Based Polymer Electrolyte toward Monolithic Sodium Ion Batteries.

PubMed

Zhang, Jianjun; Wen, Huijie; Yue, Liping; Chai, Jingchao; Ma, Jun; Hu, Pu; Ding, Guoliang; Wang, Qingfu; Liu, Zhihong; Cui, Guanglei; Chen, Liquan

2017-01-01

Sodium ion battery is one of the promising rechargeable batteries due to the low-cost and abundant sodium sources. In this work, a monolithic sodium ion battery based on a Na 3 V 2 (PO 4 ) 3 cathode, MoS 2 layered anode, and polyether-based polymer electrolyte is reported. In addition, a new kind of polysulfonamide-supported poly(ethylene glycol) divinyl ether based polymer electrolyte is also demonstrated for monolithic sodium ion battery via in situ preparation. The resultant polymer electrolyte exhibits relatively high ionic conductivity (1.2 mS cm -1 ) at ambient temperature, wide electrochemical window (4.7 V), and favorable mechanical strength (25 MPa). Moreover, such a monolithic Na 3 V 2 (PO 4 ) 3 /MoS 2 sodium ion battery using this polymer electrolyte delivers outstanding rate capability (up to 10 C) and superior cyclic stability (84%) after 1000 cycles at 0.5 C. What is more essential, such a polymer electrolyte based soft-package monolithic sodium ion cell can still power a red light emitting diode lamp and run finite times without suffering from any internal short-circuit failures, even in the case of a bended and wrinkled state. Considering these aspects, this work no doubt provides a new approach for the design of a high-performance polymer electrolyte toward monolithic sodium ion battery with exceptional rate capability and high safety. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Encoding methods for B1+ mapping in parallel transmit systems at ultra high field

NASA Astrophysics Data System (ADS)

Tse, Desmond H. Y.; Poole, Michael S.; Magill, Arthur W.; Felder, Jörg; Brenner, Daniel; Jon Shah, N.

2014-08-01

Parallel radiofrequency (RF) transmission, either in the form of RF shimming or pulse design, has been proposed as a solution to the B1+ inhomogeneity problem in ultra high field magnetic resonance imaging. As a prerequisite, accurate B1+ maps from each of the available transmit channels are required. In this work, four different encoding methods for B1+ mapping, namely 1-channel-on, all-channels-on-except-1, all-channels-on-1-inverted and Fourier phase encoding, were evaluated using dual refocusing acquisition mode (DREAM) at 9.4 T. Fourier phase encoding was demonstrated in both phantom and in vivo to be the least susceptible to artefacts caused by destructive RF interference at 9.4 T. Unlike the other two interferometric encoding schemes, Fourier phase encoding showed negligible dependency on the initial RF phase setting and therefore no prior B1+ knowledge is required. Fourier phase encoding also provides a flexible way to increase the number of measurements to increase SNR, and to allow further reduction of artefacts by weighted decoding. These advantages of Fourier phase encoding suggest that it is a good choice for B1+ mapping in parallel transmit systems at ultra high field.

Means and method for characterizing high power, ultra short laser pulses in a real time, on line manner

DOEpatents

Veligdan, J.T.

1994-03-08

An ultra short (<10 ps), high power laser pulse is temporally characterized by a system that uses a physical measurement of a wavefront that has been altered in a known manner. The system includes a first reflection switch to remove a portion of a pulse from a beam of pulses, then includes a second reflection switch, operating in a mode that is opposite to the first reflection switch, to slice off a portion of that removed portion. The sliced portion is then directed to a measuring device for physical measurement. The two reflection switches are arranged with respect to each other and with respect to the beam of ultra short pulses such that physical measurement of the sliced portion is related to the temporal measurement of the ultra short pulse by a geometric or trigonometric relationship. The reflection switches are operated by a control pulse that is directed to impinge on each of the reflection switches at a 90[degree] angle of incidence. 8 figures.

Means and method for characterizing high power, ultra short laser pulses in a real time, on line manner

DOEpatents

Veligdan, James T.

1994-01-01

An ultra short (<10 ps), high power laser pulse is temporally characterized by a system that uses a physical measurement of a wavefront that has been altered in a known manner. The system includes a first reflection switch to remove a portion of a pulse from a beam of pulses, then includes a second reflection switch, operating in a mode that is opposite to the first reflection switch, to slice off a portion of that removed portion. The sliced portion is then directed to a measuring device for physical measurement. The two reflection switches are arranged with respect to each other and with respect to the beam of ultra short pulses such that physical measurement of the sliced portion is related to the temporal measurement of the ultra short pulse by a geometric or trigonometric relationship. The reflection switches are operated by a control pulse that is directed to impinge on each of the reflection switches at a 90.degree. angle of incidence.

Low-power bacteriorhodopsin-silicon n-channel metal-oxide field-effect transistor photoreceiver.

PubMed

Shin, Jonghyun; Bhattacharya, Pallab; Yuan, Hao-Chih; Ma, Zhenqiang; Váró, György

2007-03-01

A bacteriorhodopsin (bR)-silicon n-channel metal-oxide field-effect transistor (NMOSFET) monolithically integrated photoreceiver is demonstrated. The bR film is selectively formed on an external gate electrode of the transistor by electrophoretic deposition. A modified biasing circuit is incorporated, which helps to match the resistance of the bR film to the input impedance of the NMOSFET and to shift the operating point of the transistor to coincide with the maximum gain. The photoreceiver exhibits a responsivity of 4.7 mA/W.

Window-Based Channel Impulse Response Prediction for Time-Varying Ultra-Wideband Channels.

PubMed

Al-Samman, A M; Azmi, M H; Rahman, T A; Khan, I; Hindia, M N; Fattouh, A

2016-01-01

This work proposes channel impulse response (CIR) prediction for time-varying ultra-wideband (UWB) channels by exploiting the fast movement of channel taps within delay bins. Considering the sparsity of UWB channels, we introduce a window-based CIR (WB-CIR) to approximate the high temporal resolutions of UWB channels. A recursive least square (RLS) algorithm is adopted to predict the time evolution of the WB-CIR. For predicting the future WB-CIR tap of window wk, three RLS filter coefficients are computed from the observed WB-CIRs of the left wk-1, the current wk and the right wk+1 windows. The filter coefficient with the lowest RLS error is used to predict the future WB-CIR tap. To evaluate our proposed prediction method, UWB CIRs are collected through measurement campaigns in outdoor environments considering line-of-sight (LOS) and non-line-of-sight (NLOS) scenarios. Under similar computational complexity, our proposed method provides an improvement in prediction errors of approximately 80% for LOS and 63% for NLOS scenarios compared with a conventional method.

Window-Based Channel Impulse Response Prediction for Time-Varying Ultra-Wideband Channels

PubMed Central

Al-Samman, A. M.; Azmi, M. H.; Rahman, T. A.; Khan, I.; Hindia, M. N.; Fattouh, A.

2016-01-01

This work proposes channel impulse response (CIR) prediction for time-varying ultra-wideband (UWB) channels by exploiting the fast movement of channel taps within delay bins. Considering the sparsity of UWB channels, we introduce a window-based CIR (WB-CIR) to approximate the high temporal resolutions of UWB channels. A recursive least square (RLS) algorithm is adopted to predict the time evolution of the WB-CIR. For predicting the future WB-CIR tap of window wk, three RLS filter coefficients are computed from the observed WB-CIRs of the left wk−1, the current wk and the right wk+1 windows. The filter coefficient with the lowest RLS error is used to predict the future WB-CIR tap. To evaluate our proposed prediction method, UWB CIRs are collected through measurement campaigns in outdoor environments considering line-of-sight (LOS) and non-line-of-sight (NLOS) scenarios. Under similar computational complexity, our proposed method provides an improvement in prediction errors of approximately 80% for LOS and 63% for NLOS scenarios compared with a conventional method. PMID:27992445

Ultra-bright γ-ray flashes and dense attosecond positron bunches from two counter-propagating laser pulses irradiating a micro-wire target.

PubMed

Li, Han-Zhen; Yu, Tong-Pu; Hu, Li-Xiang; Yin, Yan; Zou, De-Bin; Liu, Jian-Xun; Wang, Wei-Quan; Hu, Shun; Shao, Fu-Qiu

2017-09-04

We propose a novel scheme to generate ultra-bright ultra-short γ-ray flashes and high-energy-density attosecond positron bunches by using multi-dimensional particle-in-cell simulations with quantum electrodynamics effects incorporated. By irradiating a 10 PW laser pulse with an intensity of 10 23 W/cm 2 onto a micro-wire target, surface electrons are dragged-out of the micro-wire and are effectively accelerated to several GeV energies by the laser ponderomotive force, forming relativistic attosecond electron bunches. When these electrons interact with the probe pulse from the other side, ultra-short γ-ray flashes are emitted with an ultra-high peak brightness of 1.8 × 10 24 photons s -1 mm -2 mrad -2 per 0.1%BW at 24 MeV. These photons propagate with a low divergence and collide with the probe pulse, triggering the Breit-Wheeler process. Dense attosecond e - e + pair bunches are produced with the positron energy density as high as 10 17 J/m 3 and number of 10 9 . Such ultra-bright ultra-short γ-ray flashes and secondary positron beams may have potential applications in fundamental physics, high-energy-density physics, applied science and laboratory astrophysics.

155- and 213-GHz AlInAs/GaInAs/InP HEMT MMIC oscillators

NASA Technical Reports Server (NTRS)

Rosenbaum, Steven E.; Kormanyos, Brian K.; Jelloian, Linda M.; Matloubian, Mehran; Brown, April S.; Larson, Lawrence E.; Nguyen, Loi D.; Thompson, Mark A.; Katehi, Linda P. B.; Rebeiz, Gabriel M.

1995-01-01

We report on the design and measurement of monolithic 155- and 213-GHz quasi-optical oscillators using AlInAs/GaInAs/InP HEMTs (high-electron mobility transistors). These results are believed to be the highest frequency three-terminal oscillators reported to date. The indium concentration in the channel was 80% for high sheet charge and mobility. The HEMT gates were fabricated with self-aligned sub-tenth-micrometer electron-beam techniques to achieve gate lengths on the order of 50 nm and drain-source spacing of 0.25 micron. Planar antennas were integrated into the fabrication process resulting in a compact and efficient quasi-optical Monolithic Millimeter-wave Integrated Circuit (MMIC) oscillator.

Guiding of High Laser Intensities in Long Plasma Channels

NASA Astrophysics Data System (ADS)

Levin, M.; Eisenmann, S.; Palchan, T.; Zigler, A.; Sugiyama, K.; Nakajima, K.; Kaganovich, D.; Hubbard, R. F.; Ting, A.; Gordon, D. F.; Sprangle, P.; Fraenkel, M.; Maman, S.; Henis, Z.

Plasma channels have been widely used to guide intense laser pulses over many Rayleigh lengths. Using optimized segmented capillary discharges, we demonstrated guided propagation of ultra short (100 fs) high intensity (1016 W/cm-2, limited by the laser system) pulses over distances up to 12.6 cm and intensities above 1018W/cm2 for 1.5cm boron nitride capillary. Both radial and longitudinal density profiles of plasma channels were studied under various discharge conditions. A new diagnostic technique is presented in which the transport of a guided laser pulse at different delay times from the initiation of the discharge is sampled on a single discharge shot. Using external, 10 nsec Nd YAG laser of several tenths of milijoules to ignite polyethylene capillaries we have demonstrated channels of various length in density range of 1017 - 1019 cm-3 and up to 25% deep. The longitudinal profiles were found to be remarkably uniform in both short and long capillaries. The Boron Nitride capillary has provided a guiding medium that can withstand more than 1000 shots. Using these capillaries we have guided laser intensities above 1018W/cm2. The laser ignition of capillary discharge provided reliable almost jitter free approach. The concerns related to influence of relatively high current density flow through capillary on the injected electrons were studied extensively by us both theoretically and experimentally using a simple injection method. The method is based on the interaction of a high intensity laser pulse with a thin wire placed near capillary entrance. The influence of magnetic fields was found to be insignificant. Using this method we have studied transport of electrons though capillary discharge.

A 1.3-μm four-channel directly modulated laser array fabricated by SAG-Upper-SCH technology

NASA Astrophysics Data System (ADS)

Guo, Fei; Lu, Dan; Zhang, Ruikang; Liu, Songtao; Sun, Mengdie; Kan, Qiang; Ji, Chen

2017-01-01

A monolithically integrated four-channel directly modulated laser (DML) array working at the 1.3-μm band is demonstrated. The laser was manufactured by using the techniques of selective area growth (SAG) of the upper separate confinement heterostructure (Upper-SCH) and modified butt-joint method. The fabricated device showed stable single mode operation with the side mode suppression ratio (SMSR) >35 dB, and high wavelength accuracy with the deviations from the linear fitted values <±0.03 nm for all channels. Furthermore, small signal modulation bandwidth >7 GHz was obtained, which may be suitable for 40 GbE applications in the 1.3-μm band.

Silicon on ferroelectic insulator field effect transistor (SOF-FET) a new device for the next generation ultra low power circuits

NASA Astrophysics Data System (ADS)

Es-Sakhi, Azzedin D.

Field effect transistors (FETs) are the foundation for all electronic circuits and processors. These devices have progressed massively to touch its final steps in sub-nanometer level. Left and right proposals are coming to rescue this progress. Emerging nano-electronic devices (resonant tunneling devices, single-atom transistors, spin devices, Heterojunction Transistors rapid flux quantum devices, carbon nanotubes, and nanowire devices) took a vast share of current scientific research. Non-Si electronic materials like III-V heterostructure, ferroelectric, carbon nanotubes (CNTs), and other nanowire based designs are in developing stage to become the core technology of non-classical CMOS structures. FinFET present the current feasible commercial nanotechnology. The scalability and low power dissipation of this device allowed for an extension of silicon based devices. High short channel effect (SCE) immunity presents its major advantage. Multi-gate structure comes to light to improve the gate electrostatic over the channel. The new structure shows a higher performance that made it the first candidate to substitute the conventional MOSFET. The device also shows a future scalability to continue Moor's Law. Furthermore, the device is compatible with silicon fabrication process. Moreover, the ultra-low-power (ULP) design required a subthreshold slope lower than the thermionic-emission limit of 60mV/ decade (KT/q). This value was unbreakable by the new structure (SOI-FinFET). On the other hand most of the previews proposals show the ability to go beyond this limit. However, those pre-mentioned schemes have publicized a very complicated physics, design difficulties, and process non-compatibility. The objective of this research is to discuss various emerging nano-devices proposed for ultra-low-power designs and their possibilities to replace the silicon devices as the core technology in the future integrated circuit. This thesis proposes a novel design that exploits the concept of negative capacitance. The new field effect transistor (FET) based on ferroelectric insulator named Silicon-On-Ferroelectric Insulator Field Effect Transistor (SOF-FET). This proposal is a promising methodology for future ultra-low-power applications, because it demonstrates the ability to replace the silicon-bulk based MOSFET, and offers subthreshold swing significantly lower than 60mV/decade and reduced threshold voltage to form a conducting channel. The SOF-FET can also solve the issue of junction leakage (due to the presence of unipolar junction between the top plate of the negative capacitance and the diffused areas that form the transistor source and drain). In this device the charge hungry ferroelectric film already limits the leakage.

Ultra-compact, flat-top demultiplexer using anti-reflection contra-directional couplers for CWDM networks on silicon.

PubMed

Shi, Wei; Yun, Han; Lin, Charlie; Greenberg, Mark; Wang, Xu; Wang, Yun; Fard, Sahba Talebi; Flueckiger, Jonas; Jaeger, Nicolas A F; Chrostowski, Lukas

2013-03-25

Wavelength-division-multiplexing (WDM) networks with wide channel grids and bandwidths are promising for low-cost, low-power optical interconnects. Wide-bandwidth, single-band (i.e., no free-spectral range) add-drop filters have been developed on silicon using anti-reflection contra-directional couplers with out-of-phase Bragg gratings. Using such filter components, we demonstrate a 4-channel, coarse-WDM demultiplexer with flat passbands of up to 13 nm and an ultra-compact size of 1.2 × 10(-3) mm(2).

Monolithic carrier-envelope phase-stabilization scheme.

PubMed

Fuji, Takao; Rauschenberger, Jens; Apolonski, Alexander; Yakovlev, Vladislav S; Tempea, Gabriel; Udem, Thomas; Gohle, Christoph; Hänsch, Theodor W; Lehnert, Walter; Scherer, Michael; Krausz, Ferenc

2005-02-01

A new scheme for stabilizing the carrier-envelope (CE) phase of a few-cycle laser pulse train is demonstrated. Self-phase modulation and difference-frequency generation in a single periodically poled lithium niobate crystal that transmits the main laser beam allows CE phase locking directly in the usable output. The monolithic scheme obviates the need for splitting off a fraction of the laser output for CE phase control, coupling into microstructured fiber, and separation and recombination of spectral components. As a consequence, the output yields 6-fs, 800-nm pulses with an unprecedented degree of short- and long-term reproducibility of the electric field waveform.

Analysis of electrical characteristics and proposal of design guide for ultra-scaled nanoplate vertical FET and 6T-SRAM

NASA Astrophysics Data System (ADS)

Seo, Youngsoo; Kim, Shinkeun; Ko, Kyul; Woo, Changbeom; Kim, Minsoo; Lee, Jangkyu; Kang, Myounggon; Shin, Hyungcheol

2018-02-01

In this paper, electrical characteristics of gate-all-around (GAA) nanoplate (NP) vertical FET (VFET) were analyzed for single transistor and 6T-SRAM cell through 3D technology computer-aided design (TCAD) simulation. In VFET, gate and extension lengths are not limited by the area of device because theses lengths are vertically located. The height of NP is assumed in 40 nm considering device fabrication method (top-down approach). According to the sizes of devices, we analyzed the performances of device such as total resistance, capacitance, intrinsic gate delay, sub-threshold swing (S.S), drain-induced barrier lowering (DIBL) and static noise margin (SNM). As the gate length becomes larger, the resistance should be smaller because the total height of NP is fixed in 40 nm. Also, when the channel thickness becomes thicker, the total resistance becomes smaller since the sheet resistances of channel and extension become smaller and the contact resistance becomes smaller due to the increasing contact area. In addition, as the length of channel pitch increases, the parasitic capacitance comes to be larger due to the increasing area of gate-drain and gate-source. The performance of RC delay is best in the shortest gate length (12 nm), the thickest channel (6 nm) and the shortest channel pitch (17 nm) owing to the reduced resistance and parasitic capacitance. However, the other performances such as DIBL, S.S, on/off ratio and SNM are worst because the short channel effect is highest in this situation. Also, we investigated the performance of the multi-channel device. As the number of channels increases, the performance of device and the reliability of SRAM improve because of reduced contact resistance, increased gate dimension and multi-channel compensation effect.

Low temperature perovskite solar cells with an evaporated TiO 2 compact layer for perovskite silicon tandem solar cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bett, Alexander J.; Schulze, Patricia S. C.; Winkler, Kristina

Silicon-based tandem solar cells can overcome the efficiency limit of single junction silicon solar cells. Perovskite solar cells are particularly promising as a top cell in monolithic tandem devices due to their rapid development towards high efficiencies, a tunable band gap with a sharp optical absorption edge and a simple production process. In monolithic tandem devices, the perovskite solar cell is deposited directly on the silicon cell, requiring low-temperature processes (< 200 °C) to maintain functionality of under-lying layers of the silicon cell in case of highly efficient silicon hetero-junction (SHJ) bottom solar cell. In this work, we present amore » complete low-temperature process for perovskite solar cells including a mesoporous titanium oxide (TiO 2) scaffold - a structure yielding the highest efficiencies for single-junction perovskite solar cells. We show that evaporation of the compact TiO 2 hole blocking layer and ultra-violet (UV) curing for the mesoporous TiO 2 layer allows for good performance, comparable to high-temperature (> 500 °C) processes. With both manufacturing routes, we obtain short-circuit current densities (J SC) of about 20 mA/cm 2, open-circuit voltages (V OC) over 1 V, fill factors (FF) between 0.7 and 0.8 and efficiencies (n) of more than 15%. We further show that the evaporated TiO 2 layer is suitable for the application in tandem devices. The series resistance of the layer itself and the contact resistance to an indium doped tin oxide (ITO) interconnection layer between the two sub-cells are low. Additionally, the low parasitic absorption for wavelengths above the perovskite band gap allow a higher absorption in the silicon bottom solar cell, which is essential to achieve high tandem efficiencies.« less

Low temperature perovskite solar cells with an evaporated TiO 2 compact layer for perovskite silicon tandem solar cells

DOE PAGES

Bett, Alexander J.; Schulze, Patricia S. C.; Winkler, Kristina; ...

2017-09-21

Silicon-based tandem solar cells can overcome the efficiency limit of single junction silicon solar cells. Perovskite solar cells are particularly promising as a top cell in monolithic tandem devices due to their rapid development towards high efficiencies, a tunable band gap with a sharp optical absorption edge and a simple production process. In monolithic tandem devices, the perovskite solar cell is deposited directly on the silicon cell, requiring low-temperature processes (< 200 °C) to maintain functionality of under-lying layers of the silicon cell in case of highly efficient silicon hetero-junction (SHJ) bottom solar cell. In this work, we present amore » complete low-temperature process for perovskite solar cells including a mesoporous titanium oxide (TiO 2) scaffold - a structure yielding the highest efficiencies for single-junction perovskite solar cells. We show that evaporation of the compact TiO 2 hole blocking layer and ultra-violet (UV) curing for the mesoporous TiO 2 layer allows for good performance, comparable to high-temperature (> 500 °C) processes. With both manufacturing routes, we obtain short-circuit current densities (J SC) of about 20 mA/cm 2, open-circuit voltages (V OC) over 1 V, fill factors (FF) between 0.7 and 0.8 and efficiencies (n) of more than 15%. We further show that the evaporated TiO 2 layer is suitable for the application in tandem devices. The series resistance of the layer itself and the contact resistance to an indium doped tin oxide (ITO) interconnection layer between the two sub-cells are low. Additionally, the low parasitic absorption for wavelengths above the perovskite band gap allow a higher absorption in the silicon bottom solar cell, which is essential to achieve high tandem efficiencies.« less

Overview and Recent Accomplishments of Advanced Mirror Technology Development Phase 2 (AMTD-2)

NASA Technical Reports Server (NTRS)

Stahl, H. Philip

2015-01-01

AMTD uses a science-driven systems engineering approach to define & execute a long-term strategy to mature technologies necessary to enable future large aperture space telescopes. Because we cannot predict the future, we are pursuing multiple technology paths including monolithic & segmented mirrors. Assembled outstanding team from academia, industry & government; experts in science & space telescope engineering. Derived engineering specifications from science measurement needs & implementation constraints. Maturing 6 critical technologies required to enable 4 to 8 meter UVOIR space telescope mirror assemblies for both general astrophysics & ultra-high contrast exoplanet imaging. AMTD achieving all its goals & accomplishing all its milestones.

Development of large-area monolithically integrated silicon-film photovoltaic modules

NASA Astrophysics Data System (ADS)

Rand, J. A.; Cotter, J. E.; Ingram, A. E.; Ruffins, T. R.; Shreve, K. P.; Hall, R. B.; Barnett, A. M.

1993-06-01

This report describes work to develop Silicon-Film (trademark) Product 3 into a low-cost, stable solar cell for large-scale terrestrial power applications. The Product 3 structure is a thin (less than 100 micron) polycrystalline layer of silicon on a durable, insulating, ceramic substrate. The insulating substrate allows the silicon layer to be isolated and metallized to form a monolithically interconnected array of solar cells. High efficiency is achievable with the use of light trapping and a passivated back surface. The long-term goal for the product is a 1200 sq cm, 18%-efficient, monolithic array. The short-term objectives are to improve material quality and to fabricate 100 sq cm monolithically interconnected solar cell arrays. Low minority-carrier diffusion length in the silicon film and series resistance in the interconnected device structure are presently limiting device performance. Material quality is continually improving through reduced impurity contamination. Metallization schemes, such as a solder-dipped interconnection process, have been developed that will allow low-cost production processing and minimize R(sub s) effects. Test data for a nine-cell device (16 sq cm) indicated a V(sub oc) of 3.72 V. These first-reported monolithically interconnected multicrystalline silicon-on-ceramic devices show low shunt conductance (less than 0.1 mA/sq cm) due to limited conduction through the ceramic and no process-related metallization shunts.

How Do Earth-Sized, Short-Period Planets Form?

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2017-08-01

Matching theory to observation often requires creative detective work. In a new study, scientists have used a clever test to reveal clues about the birth of speedy, Earth-sized planets.Former Hot Jupiters?Artists impression of a hot Jupiter with an evaporating atmosphere. [NASA/Ames/JPL-Caltech]Among the many different types of exoplanets weve observed, one unusual category is that of ultra-short-period planets. These roughly Earth-sized planets speed around their host stars at incredible rates, with periods of less than a day.How do planets in this odd category form? One popular theory is that they were previously hot Jupiters, especially massive gas giants orbiting very close to their host stars. The close orbit caused the planets atmospheres to be stripped away, leaving behind only their dense cores.In a new study, a team of astronomers led by Joshua Winn (Princeton University) has found a clever way to test this theory.Planetary radius vs. orbital period for the authors three statistical samples (colored markers) and the broader sample of stars in the California Kepler Survey. [Winn et al. 2017]Testing MetallicitiesStars hosting hot Jupiters have an interesting quirk: they typically have metallicities that are significantly higher than an average planet-hosting star. It is speculated that this is because planets are born from the same materials as their host stars, and hot Jupiters require the presence of more metals to be able to form.Regardless of the cause of this trend, if ultra-short-period planets are in fact the solid cores of former hot Jupiters, then the two categories of planets should have hosts with the same metallicity distributions. The ultra-short-period-planet hosts should therefore also be weighted to higher metallicities than average planet-hosting stars.To test this, the authors make spectroscopic measurements and gather data for a sample of stellar hosts split into three categories:64 ultra-short-period planets (orbital period shorter than a day)23 hot Jupiters (larger than 4 times Earths radius and orbital period shorter than 10 days)243 small hot planets (smaller than 4 times Earths radius and orbital period between 1 and 10 days)They then compare the metallicity distributions of these three groups.Back to the Drawing BoardMetallicity distributions of the three statistical samples. The hot-Jupiter hosts (orange) have different distribution than the others; it is weighted more toward higher metallicities. [Winn et al. 2017]Winn and collaborators find that hosts of ultra-short-period planets do not have the same metallicity distribution as hot-Jupiter hosts; the metallicities of hot-Jupiter hosts are significantly higher. The metallicity distributions for hosts of ultra-short-period planets and hosts of small hot planets were statistically indistinguishable, however.These results strongly suggest that the majority of ultra-short-period planets are not the cores of former hot Jupiters. Alternative options include the possibility that they are the cores of smaller planets, such as sub-Neptunes, or that they are the short-period extension of the distribution of close-in, small rocky planets that formed by core accretion.This narrowing of the options for the formation of ultra-short-period planets is certainly intriguing. We can hope to further explore possibilities in the future after the Transiting Exoplanet Survey Satellites (TESS) comes online next year; TESS is expected to discover many more ultra-short-period planets that are too faint for Kepler to detect.CitationJoshua N. Winn et al 2017 AJ 154 60. doi:10.3847/1538-3881/aa7b7c

Ultra-compact coherent receiver with serial interface for pluggable transceiver.

PubMed

Itoh, Toshihiro; Nakajima, Fumito; Ohno, Tetsuichiro; Yamanaka, Shogo; Soma, Shunichi; Saida, Takashi; Nosaka, Hideyuki; Murata, Koichi

2014-09-22

An ultra-compact integrated coherent receiver with a volume of 1.3 cc using a quad-channel transimpedance amplifier (TIA)-IC chip with a serial peripheral interface (SPI) is demonstrated for the first time. The TIA with the SPI and photodiode (PD) bias circuits, a miniature dual polarization optical hybrid, an octal-PD and small optical coupling system enabled the realization of the compact receiver. Measured transmission performance with 32 Gbaud dual-polarization quadrature phase shift keying signal is equivalent to that of the conventional multi-source agreement-based integrated coherent receiver with dual channel TIA-ICs. By comparing the bit-error rate (BER) performance with that under continuous SPI access, we also confirmed that there is no BER degradation caused by SPI interface access. Such an ultra-compact receiver is promising for realizing a new generation of pluggable transceivers.

113Gb/s (10 x 11.3Gb/s) ultra-low power EAM driver array.

PubMed

Vaernewyck, Renato; Bauwelinck, Johan; Yin, Xin; Pierco, Ramses; Verbrugghe, Jochen; Torfs, Guy; Li, Zhisheng; Qiu, Xing-Zhi; Vandewege, Jan; Cronin, Richard; Borghesani, Anna; Moodie, David

2013-01-14

This paper presents an ultra-low power SiGe BiCMOS IC for driving a 10 channel electro-absorption modulator (EAM) array at 113Gb/s for wavelength division multiplexing passive optical network (WDM-PON) applications. With an output swing of 2.5V(pp), the EAM driver array consumes only 2.2W or 220mW per channel, 50% below the state of the art. Both the output swing and bias are configurable between 1.5 and 3.0V(pp) and 0.75-2.15V respectively.

Implementation of the multi-channel monolith reactor in an optimisation procedure for heterogeneous oxidation catalysts based on genetic algorithms.

PubMed

Breuer, Christian; Lucas, Martin; Schütze, Frank-Walter; Claus, Peter

2007-01-01

A multi-criteria optimisation procedure based on genetic algorithms is carried out in search of advanced heterogeneous catalysts for total oxidation. Simple but flexible software routines have been created to be applied within a search space of more then 150,000 individuals. The general catalyst design includes mono-, bi- and trimetallic compositions assembled out of 49 different metals and depleted on an Al2O3 support in up to nine amount levels. As an efficient tool for high-throughput screening and perfectly matched to the requirements of heterogeneous gas phase catalysis - especially for applications technically run in honeycomb structures - the multi-channel monolith reactor is implemented to evaluate the catalyst performances. Out of a multi-component feed-gas, the conversion rates of carbon monoxide (CO) and a model hydrocarbon (HC) are monitored in parallel. In combination with further restrictions to preparation and pre-treatment a primary screening can be conducted, promising to provide results close to technically applied catalysts. Presented are the resulting performances of the optimisation process for the first catalyst generations and the prospect of its auto-adaptation to specified optimisation goals.

Technique for long and absolute distance measurement based on laser pulse repetition frequency sweeping

NASA Astrophysics Data System (ADS)

Castro Alves, D.; Abreu, Manuel; Cabral, A.; Jost, Michael; Rebordão, J. M.

2017-11-01

In this work we present a technique to perform long and absolute distance measurements based on mode-locked diode lasers. Using a Michelson interferometer, it is possible to produce an optical cross-correlation between laser pulses of the reference arm with the pulses from the measurement arm, adjusting externally their degree of overlap either changing the pulse repetition frequency (PRF) or the position of the reference arm mirror for two (or more) fixed frequencies. The correlation of the travelling pulses for precision distance measurements relies on ultra-short pulse durations, as the uncertainty associated to the method is dependent on the laser pulse width as well as on a highly stable PRF. Mode-locked Diode lasers are a very appealing technology for its inherent characteristics, associated to compactness, size and efficiency, constituting a positive trade-off with regard to other mode-locked laser sources. Nevertheless, main current drawback is the non-availability of frequency-stable laser diodes. The laser used is a monolithic mode-locked semiconductor quantum-dot (QD) laser. The laser PRF is locked to an external stabilized RF reference. In this work we will present some of the preliminary results and discuss the importance of the requirements related to laser PRF stability in the final metrology system accuracy.

Organic field effect transistor with ultra high amplification

NASA Astrophysics Data System (ADS)

Torricelli, Fabrizio

2016-09-01

High-gain transistors are essential for the large-scale circuit integration, high-sensitivity sensors and signal amplification in sensing systems. Unfortunately, organic field-effect transistors show limited gain, usually of the order of tens, because of the large contact resistance and channel-length modulation. Here we show organic transistors fabricated on plastic foils enabling unipolar amplifiers with ultra-gain. The proposed approach is general and opens up new opportunities for ultra-large signal amplification in organic circuits and sensors.

General and simple approach for control cage and cylindrical mesopores, and thermal/hydrothermal stable frameworks.

PubMed

El-Safty, Sherif A; Mizukami, Fujio; Hanaoka, Takaaki

2005-05-19

Highly ordered cage and cylindrical mesoporeous silica monoliths (HOM) with 2- and 3-dimensional (2D and 3D, respectively) structures, mesopore/micropore volumes, and thick-walled frameworks were successfully fabricated by instant direct templating of lyotropic phases of copolymer (EO(m)-PO(n)-EO(m)) surfactants. Large cage-like pores with uniform constriction sizes up to 10 nm and open cylindrical channel-like mesopores can be easily achieved by this simple and efficient synthesis design. Our results show that the cage-like pores could be fabricated at relatively lower copolymer concentrations used in the lyotropic phase domains at copolymer/TMOS ratios of 35 wt %. These ordered cage pore architectures underwent transition to open-cylindrical pores by increasing the copolymer concentration. High EO/PO block copolymers, in general, were crucially affected on the increase of the interior cavity sizes and on the stability of the cage mesopore characters. However, for F108 (EO(141)PO(44)EO(141)) systems, the fabrication of ordered and stable cage pore monoliths was achieved with significantly higher copolymer concentrations up to 90 wt %. Interestingly, the effective copolymer molecular nature was also observed in the ability to design various ordered mesophase geometries in large domain sizes. Our findings here show evidence that the synthetic strategy provides realistic control over a wide range of mesostructured phase geometries and their extended long-range ordering in the final replicas of the silica monolith frameworks. In addition, the HOM silica monoliths exhibited considerable structural stability against higher thermal temperature (up to 1000 degrees C) and longer hydrothermal treatment times under boiling water and steam. The remarkable structural findings of 3D frameworks, transparent monoliths, and micropores combined with large cage- and cylindrical-like mesopores are expected to find promising uses in materials chemistry.

DPSSL for direct dicing and drilling of dielectrics

NASA Astrophysics Data System (ADS)

Ashkenasi, David; Schwagmeier, M.

2007-02-01

New strategies in laser micro processing of glasses and other optically transparent materials are being developed with increasing interest and intensity using diode pumped solid state laser (DPSSL) systems generating short or ultra-short pulses in the optical spectra at good beam quality. Utilizing non-linear absorption channels, it can be demonstrated that ns green (532 nm) laser light can scribe, dice, full body cut and drill (flat) borofloat and borosilicate glasses at good quality. Outside of the correct choice in laser parameters, an intelligent laser beam management plays an important role in successful micro processing of glass. This application characterizes a very interesting alternative where standard methods demonstrate severe limitations such as diamond dicing, CO2 laser treatment or water jet cutting, especially for certain type of optical materials and/or geometric conditions. Application near processing examples using different DPSSL systems generating ns pulsed light at 532 nm in TEM 00 at average powers up to 10 W are presented and discussed in respect to potential applications in display technology, micro electronics and optics.

Developing Low-Power Transceiver Technologies for In Situ Communication Applications

NASA Astrophysics Data System (ADS)

Lay, N.; Cheetham, C.; Mojaradi, H.; Neal, J.

2001-07-01

For future deep-space missions, significant reductions in the mass and power requirements for short-range telecommunication systems will be critical in enabling a wide variety of new mission concepts. These possibilities include penetrators, gliders, miniature rovers, balloons, and sensor networks. The recent development activity reported in this article has focused on the design of ultra-low-mass and -power transceiver systems and subsystems suitable for operation in a flight environment. Under these efforts, the basic functionality of the transceiver has been targeted towards a Mars microprobe communications scenario. However, the overall transceiver architecture is well suited to any short- or medium-range application where a remote probe will aperiodically communicate with a base station, possibly an orbiter, for the eventual purpose of relaying science information back to Earth. Additionally, elements of the radio architecture can be applied in situations involving surface-to-surface communications, thereby enabling different mission communications topologies. Through a system analysis of these channels, both the applicability and benefit of very low power communications will be quantitatively addressed.

Processing of continuous fiber reinforced ceramic composites for ultra high temperature applications using organosilicon polymer precursors

NASA Astrophysics Data System (ADS)

Nicholas, James Robert

The current work is on the development of continuous fiber reinforced ceramic materials (CFCCs) for use in ultra high temperature applications. These applications subject materials to extremely high temperatures(> 2000°C). Monolithic ceramics are currently being used for these applications, but the tendency to fail catastrophically has driven the need for the next generation of material. Reinforcing with continuous fibers significantly improves the toughness of the monolithic materials; however, this is a manufacturing challenge. The development of commercial, low-viscosity preceramic polymers provides new opportunities to fabricate CFCCs. Preceramic polymers behave as polymers at low temperatures and are transformed into ceramics upon heating to high temperatures. The polymer precursors enable the adaptation of well-established polymer processing techniques to produce high quality materials at relatively low cost. In the present work, SMP-10 from Starfire Systems, and PURS from KiON Corp. were used to manufacture ZrB2-SiC/SiC CFCCs using low cost vacuum bagging process in conjunction with the polymer infiltration and pyrolysis process. The microstructure was investigated using scanning electron microscopy and it was determined that the initial greenbody cure produced porosity of both closed and open pores. The open pores were found to be more successfully re-infiltrated using neat resin compared to slurry reinfiltrate; however, the closed pores were found to be impenetrable during subsequent reinfiltrations. The mechanical performance of the manufactured samples was evaluated using flexure tests and found the fiber reinforcement prevented catastrophic failure behavior by increasing fracture toughness. Wedge sample were fabricated and evaluated to demonstrate the ability to produce CFCC of complex geometry.

Short-Term Prospective Clinical Evaluation of Monolithic and Partially Veneered Zirconia Single Crowns.

PubMed

Bömicke, Wolfgang; Rammelsberg, Peter; Stober, Thomas; Schmitter, Marc

2017-02-01

The purpose of this study was to prospectively evaluate the short-term clinical performance and esthetics of monolithic and partially (i.e., facially) veneered zirconia single crowns (MZC and PZC, respectively). Between September 2011 and June 2013, 68 participants received 90 MZCs and 72 PZCs. Clinical study documentation was performed at crown cementation (baseline), at the 6-month follow-up, and then yearly thereafter using standardized report forms. Eight participants with 14 single crowns (eight MZCs and six PZCs) dropped out during clinical follow-up. Thus, 60 participants (28 male, mean age 62.5 ± 13.1 years) fitted with 82 MZCs and 66 PZCs were analyzed in February 2016 (Kaplan-Meier survival; mean observation time for the restorations 35.1 ± 6.3 months). Descriptive statistics were calculated for participants' and dentists' esthetic ratings on a numerical rating scale from 0 to 10 (0 = unacceptable color and shape; 10 = excellent color and shape). Complications were predominantly biological in nature. One PZC was affected by minor chipping. Cumulative 3-year failure-free survival was 98.5% (standard error (SE), 1.5%) for both MZCs and PZCs. Three-year cumulative complication-free survival (success) was 93.6% (SE 2.8%) for MZCs and 95.5% (SE 2.6%) for PZCs. Three-year cumulative fracture-free survival was 100% for MZCs and 98.5% (SE 1.5%) for PZCs. Crowns of both types were awarded high esthetic scores by participants and dentists. Monolithic and partially veneered zirconia crowns can be used clinically with excellent short-term survival and success and without compromising esthetic appearance. Longer-term follow-up is, however, desirable. During the observation time, both monolithic and partially veneered zirconia crowns showed an outstanding low technical complication rate: only one minor chipping and three losses of retention were observed. Additionally, esthetics was excellent. Based on these results the clinical use of this kind of restoration is promising. (J Esthet Restor Dent 29:22-30, 2017). © 2016 Wiley Periodicals, Inc.

AMTD: update of engineering specifications derived from science requirements for future UVOIR space telescopes

NASA Astrophysics Data System (ADS)

Stahl, H. Philip; Postman, Marc; Mosier, Gary; Smith, W. Scott; Blaurock, Carl; Ha, Kong; Stark, Christopher C.

2014-08-01

The Advance Mirror Technology Development (AMTD) project is in Phase 2 of a multiyear effort, initiated in FY12, to mature by at least a half TRL step six critical technologies required to enable 4 meter or larger UVOIR space telescope primary mirror assemblies for both general astrophysics and ultra-high contrast observations of exoplanets. AMTD uses a science-driven systems engineering approach. We mature technologies required to enable the highest priority science AND provide a high-performance low-cost low-risk system. To give the science community options, we are pursuing multiple technology paths. A key task is deriving engineering specifications for advanced normal-incidence monolithic and segmented mirror systems needed to enable both general astrophysics and ultra-high contrast observations of exoplanets missions as a function of potential launch vehicles and their mass and volume constraints. A key finding of this effort is that the science requires an 8 meter or larger aperture telescope.

AMTD: Update of Engineering Specifications Derived from Science Requirements for Future UVOIR Space Telescopes

NASA Technical Reports Server (NTRS)

Stahl, H. Philip; Postman, Marc; Mosier, Gary; Smith, W. Scott; Blaurock, Carl; Ha, Kong; Stark, Christopher C.

2014-01-01

The Advance Mirror Technology Development (AMTD) project is in Phase 2 of a multiyear effort, initiated in FY12, to mature by at least a half TRL step six critical technologies required to enable 4 meter or larger UVOIR space telescope primary mirror assemblies for both general astrophysics and ultra-high contrast observations of exoplanets. AMTD uses a science-driven systems engineering approach. We mature technologies required to enable the highest priority science AND provide a high-performance low-cost low-risk system. To give the science community options, we are pursuing multiple technology paths. A key task is deriving engineering specifications for advanced normal-incidence monolithic and segmented mirror systems needed to enable both general astrophysics and ultra-high contrast observations of exoplanets missions as a function of potential launch vehicles and their mass and volume constraints. A key finding of this effort is that the science requires an 8 meter or larger aperture telescope

Wide and ultra-wide bandgap oxides: where paradigm-shift photovoltaics meets transparent power electronics

NASA Astrophysics Data System (ADS)

Pérez-Tomás, Amador; Chikoidze, Ekaterine; Jennings, Michael R.; Russell, Stephen A. O.; Teherani, Ferechteh H.; Bove, Philippe; Sandana, Eric V.; Rogers, David J.

2018-03-01

Oxides represent the largest family of wide bandgap (WBG) semiconductors and also offer a huge potential range of complementary magnetic and electronic properties, such as ferromagnetism, ferroelectricity, antiferroelectricity and high-temperature superconductivity. Here, we review our integration of WBG and ultra WBG semiconductor oxides into different solar cells architectures where they have the role of transparent conductive electrodes and/or barriers bringing unique functionalities into the structure such above bandgap voltages or switchable interfaces. We also give an overview of the state-of-the-art and perspectives for the emerging semiconductor β- Ga2O3, which is widely forecast to herald the next generation of power electronic converters because of the combination of an UWBG with the capacity to conduct electricity. This opens unprecedented possibilities for the monolithic integration in solar cells of both self-powered logic and power electronics functionalities. Therefore, WBG and UWBG oxides have enormous promise to become key enabling technologies for the zero emissions smart integration of the internet of things.

Scalable continuous flow synthesis of ZnO nanorod arrays in 3-D ceramic honeycomb substrates for low-temperature desulfurization

DOE PAGES

Wang, Sibo; Wu, Yunchao; Miao, Ran; ...

2017-07-26

Scalable and cost-effective synthesis and assembly of technologically important nanostructures in three-dimensional (3D) substrates hold keys to bridge the demonstrated nanotechnologies in academia with industrially relevant scalable manufacturing. In this paper, using ZnO nanorod arrays as an example, a hydrothermal-based continuous flow synthesis (CFS) method is successfully used to integrate the nano-arrays in multi-channeled monolithic cordierite. Compared to the batch process, CFS enhances the average growth rate of nano-arrays by 125%, with the average length increasing from 2 μm to 4.5 μm within the same growth time of 4 hours. The precursor utilization efficiency of CFS is enhanced by 9more » times compared to that of batch process by preserving the majority of precursors in recyclable solution. Computational fluid dynamic simulation suggests a steady-state solution flow and mass transport inside the channels of honeycomb substrates, giving rise to steady and consecutive growth of ZnO nano-arrays with an average length of 10 μm in 12 h. The monolithic ZnO nano-array-integrated cordierite obtained through CFS shows enhanced low-temperature (200 °C) desulfurization capacity and recyclability in comparison to ZnO powder wash-coated cordierite. This can be attributed to exposed ZnO {101¯0} planes, better dispersion and stronger interactions between sorbent and reactant in the ZnO nanorod arrays, as well as the sintering-resistance of nano-array configurations during sulfidation–regeneration cycles. Finally, with the demonstrated scalable synthesis and desulfurization performance of ZnO nano-arrays, a promising, industrially relevant integration strategy is provided to fabricate metal oxide nano-array-based monolithic devices for various environmental and energy applications.« less

Scalable continuous flow synthesis of ZnO nanorod arrays in 3-D ceramic honeycomb substrates for low-temperature desulfurization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Sibo; Wu, Yunchao; Miao, Ran

Scalable and cost-effective synthesis and assembly of technologically important nanostructures in three-dimensional (3D) substrates hold keys to bridge the demonstrated nanotechnologies in academia with industrially relevant scalable manufacturing. In this paper, using ZnO nanorod arrays as an example, a hydrothermal-based continuous flow synthesis (CFS) method is successfully used to integrate the nano-arrays in multi-channeled monolithic cordierite. Compared to the batch process, CFS enhances the average growth rate of nano-arrays by 125%, with the average length increasing from 2 μm to 4.5 μm within the same growth time of 4 hours. The precursor utilization efficiency of CFS is enhanced by 9more » times compared to that of batch process by preserving the majority of precursors in recyclable solution. Computational fluid dynamic simulation suggests a steady-state solution flow and mass transport inside the channels of honeycomb substrates, giving rise to steady and consecutive growth of ZnO nano-arrays with an average length of 10 μm in 12 h. The monolithic ZnO nano-array-integrated cordierite obtained through CFS shows enhanced low-temperature (200 °C) desulfurization capacity and recyclability in comparison to ZnO powder wash-coated cordierite. This can be attributed to exposed ZnO {101¯0} planes, better dispersion and stronger interactions between sorbent and reactant in the ZnO nanorod arrays, as well as the sintering-resistance of nano-array configurations during sulfidation–regeneration cycles. Finally, with the demonstrated scalable synthesis and desulfurization performance of ZnO nano-arrays, a promising, industrially relevant integration strategy is provided to fabricate metal oxide nano-array-based monolithic devices for various environmental and energy applications.« less

An Ultra Low Cost Wireless Communications Laboratory for Education and Research

ERIC Educational Resources Information Center

Linn, Y.

2012-01-01

This paper presents an ultra-low-cost wireless communications laboratory that is based on a commercial off-the-shelf field programmable gate array (FPGA) development board that is both inexpensive and available worldwide. The total cost of the laboratory is under USD $200, but it includes complete transmission, channel emulation, reception…

Short pulse fiber lasers mode-locked by carbon nanotubes and graphene

NASA Astrophysics Data System (ADS)

Yamashita, Shinji; Martinez, Amos; Xu, Bo

2014-12-01

One and two dimensional forms of carbon, carbon nanotubes and graphene, have interesting and useful, not only electronic but also photonic, properties. For fiber lasers, they are very attractive passive mode lockers for ultra-short pulse generation, since they have saturable absorption with inherently fast recovery time (<1 ps). In this paper, we review the photonic properties of graphene and CNT and our recent works on fabrication of fiber devices and applications to ultra-short pulse mode-locked fiber lasers.

Miniaturized monolithic columns for the electrochromatographic separation and SERS detection of molecules of exobiological interest

NASA Astrophysics Data System (ADS)

Carbonnier, Benjamin; Guerrouache, Mohamed

Development of miniaturized separation and detection media represents one of the major challenges in the field of modern analytical chemistry dedicated to space exploration. To date, gas chromatography-mass spectrometry has been selected as the method of choice for exobiology flight experiments for seeking for organic molecules and especially potential chemical indicators of life. [1] Liquid phase separation methods have also been developed with for instance, the so-called Mars Organic Analyzer (MOA) capillary electrophoresis (CE) microchip.[2] Although CE offers the advantages of easy miniaturization and high separation efficiency it suffers from a lack of selectivity towards a broad range of analytes with varied chemical nature. In this respect, we propose the use of capillary columns filled with monolithic stationary phases for the electrochromatographic separation of organic molecules of exobiology interest. Polymer monoliths have attracted a great deal of interest in analytical science over the last years as (electro)chromatographic stationary phases [3], immunosensors [4]. Beyond the intrinsic properties of monolithic polymers, i.e. fast mass transport between the monolithic support and the surrounding fluid and high permeability, other major advantages are their easy in situ preparation and tuning of surface functionality. Indeed, monoliths can be simply prepared through free radical copolymerization of a homogeneous mixture made of monomers, cross-linkers, porogenic solvents and initiator. UV-initiation process has been exploited to the synthesis of a discrete section of monolith as a flow-through active element within the confines of micro channels [5,6] while two-step strategies have been reported for the design of varied adsorbent starting with a generic monolith [7,8]. Although a nearly limitless range of monolithic supports can be prepared by this traditional method, the resulting monoliths exhibit unique function. In this contribution, we describe an elegant strategy for preparing multifunctional monoliths through spatially controlled surface functionalization.[9] Photochemical initiation affords spatial control over the reaction site, i.e. site-specific immobilization of ligands on the pore surface of the monolith. Hydrophobic and hydrophilic molecular entities were successfully grafted and the obtained monoliths were applied to electrochromatographic separation application under reversed-phase and hydrophilic interaction electrochromatography modes, respectively. The panel of successfully analyzed analytes ranges from hydrophobic polycyclic aromatic hydrocarbons to life markers such as amino acids and peptides. Our approach was extended to the local design of chelating interface for the site-specific immobilisation of gold nanoparticles. Taking advantage of the unique properties of supported nano-gold, it was possible to perform surface enhanced Raman spectroscopy (SERS) sensing of organic molecules at the sub-nanomolar level. This work is funded by the French Space Agency (CNES) References [1] M.C. Pietrogrande, M.G. Zampolli, F. Dondi, C. Szopa, R. Sternberg, A. Buch, J.F. Raulin, J. Chromatogr. A 1071 (2005) 255. [2] A. M. Stockton, T.M. Chiesl, J.M. Scherer, R. A. Mathies, Anal. Chem. 81 (2009) 790 [3] B. Carbonnier, M. Guerrouache, R. Denoyel, M. C. Millot, J. Sep. Sci. 30 (2007) 3000. [4] J.k. Liu, C.F. Chen, C.W. Chang, D.L. DeVoe, Biosensors Bioelectron. 26 (2010) 182. [5] J. Krenkova, F. Svec, J. Sep. Sci. 32 (2009) 706. [6] F. Svec, J. Chromatogr. B 841 (2004) 52 [7] M. Guerrouache, M. C. Millot, B. Carbonnier, Macromol. Rapid. Commun, 30 (2009) 109. [8] M. Guerrouache, B. Carbonnier, C. Vidal-Madjar, M.C. Millot, J. Chromatogr A, 1149 (2007) 368. [9] M. Guerrouache, S. Mahouche Chergui, M.M. Chehimi, B. Carbonnier. Chem. Commun. 48 (2012) 7486.

Ultra-narrow pulse generator with precision-adjustable pulse width

NASA Astrophysics Data System (ADS)

Fu, Zaiming; Liu, Hanglin

2018-05-01

In this paper, a novel ultra-narrow pulse generation approach is proposed. It is based on the decomposition and synthesis of pulse edges. Through controlling their relative delay, an ultra-narrow pulse could be generated. By employing field programmable gate array digital synthesis technology, the implemented pulse generator is with programmable ability. The amplitude of pulse signals is controlled by the radio frequency amplifiers and bias tees, and high precision can be achieved. More importantly, the proposed approach can break through the limitation of device's propagation delay and optimize the resolution and the accuracy of the pulse width significantly. The implemented pulse generator has two channels, whose minimum pulse width, frequency range, and amplitude range are 100 ps, 15 MHz-1.5 GHz, and 0.1 Vpp-1.8 Vpp, respectively. Both resolution of pulse width and channel delay are 1 ps, and amplitude resolution is 10 mVpp.

Analyzing Flash Flood Data in an Ultra-Urban Region

NASA Astrophysics Data System (ADS)

Smith, B. K.; Rodriguez, S.

2016-12-01

New York City is an ultra-urban region, with combined sewers and buried stream channels. Traditional flood studies rely on the presence of stream gages to detect flood stage and discharge, but ultra-urban regions frequently lack the surface stream channels and gages necessary for this approach. In this study we aggregate multiple non-traditional data for detecting flash flood events. These data including phone call reports, city records, and, for one particular flood event, news reports and social media reports. These data are compared with high-resolution bias-corrected radar rainfall fields to study flash flood events in New York City. We seek to determine if these non-traditional data will allow for a comprehensive study of rainfall-runoff relationships in New York City. We also seek to map warm season rainfall heterogeneities in the city and to compare them to spatial distribution of reported flood occurrence.

An eight-channel T/R head coil for parallel transmit MRI at 3T using ultra-low output impedance amplifiers

PubMed Central

Moody, Katherine Lynn; Hollingsworth, Neal A.; Zhao, Feng; Nielsen, Jon-Fredrik; Noll, Douglas C.; Wright, Steven M.; McDougall, Mary Preston

2014-01-01

Parallel transmit is an emerging technology to address the technical challenges associated with MR imaging at high field strengths. When developing arrays for parallel transmit systems, one of the primary factors to be considered is the mechanism to manage coupling and create independently operating channels. Recent work has demonstrated the use of amplifiers to provide some or all of the channel-to-channel isolation, reducing the need for on-coil decoupling networks in a manner analogous to the use of isolation preamplifiers with receive coils. This paper discusses an eight-channel transmit/receive head array for use with an ultra-low output impedance (ULOI) parallel transmit system. The ULOI amplifiers eliminated the need for a complex lumped element network to decouple the eight rung array. The design and construction details of the array are discussed in addition to the measurement considerations required for appropriately characterizing an array when using ULOI amplifiers. B1 maps and coupling matrices are used to verify the performance of the system. PMID:25072190

An eight-channel T/R head coil for parallel transmit MRI at 3T using ultra-low output impedance amplifiers

NASA Astrophysics Data System (ADS)

Moody, Katherine Lynn; Hollingsworth, Neal A.; Zhao, Feng; Nielsen, Jon-Fredrik; Noll, Douglas C.; Wright, Steven M.; McDougall, Mary Preston

2014-09-01

Parallel transmit is an emerging technology to address the technical challenges associated with MR imaging at high field strengths. When developing arrays for parallel transmit systems, one of the primary factors to be considered is the mechanism to manage coupling and create independently operating channels. Recent work has demonstrated the use of amplifiers to provide some or all of the channel-to-channel isolation, reducing the need for on-coil decoupling networks in a manner analogous to the use of isolation preamplifiers with receive coils. This paper discusses an eight-channel transmit/receive head array for use with an ultra-low output impedance (ULOI) parallel transmit system. The ULOI amplifiers eliminated the need for a complex lumped element network to decouple the eight-rung array. The design and construction details of the array are discussed in addition to the measurement considerations required for appropriately characterizing an array when using ULOI amplifiers. B1 maps and coupling matrices are used to verify the performance of the system.

Compact and high-sensitivity 100-Gb/s (4 × 25 Gb/s) APD-ROSA with a LAN-WDM PLC demultiplexer.

PubMed

Yoshimatsu, Toshihide; Nada, Masahiro; Oguma, Manabu; Yokoyama, Haruki; Ohno, Tetsuichiro; Doi, Yoshiyuki; Ogawa, Ikuo; Takahashi, Hiroshi; Yoshida, Eiji

2012-12-10

We demonstrate an integrated 100 GbE receiver optical sub-assembly (ROSA) that incorporates a monolithic four-channel avalanche photodiode (APD) array and a planer lightwave circuit (PLC) based LAN-WDM demultiplexer. A record minimum receiver sensitivity of -20 dBm and 50-km error-free SMF transmission without an optical amplifier have been achieved.

Comparison of polystyrene scintillator fiber array and monolithic polystyrene for neutron imaging and radiography.

PubMed

Simpson, R; Cutler, T E; Danly, C R; Espy, M A; Goglio, J H; Hunter, J F; Madden, A C; Mayo, D R; Merrill, F E; Nelson, R O; Swift, A L; Wilde, C H; Zocco, T G

2016-11-01

The neutron imaging diagnostic at the National Ignition Facility has been operating since 2011 generating neutron images of deuterium-tritium (DT) implosions at peak compression. The current design features a scintillating fiber array, which allows for high imaging resolution to discern small-scale structure within the implosion. In recent years, it has become clear that additional neutron imaging systems need to be constructed in order to provide 3D reconstructions of the DT source and these additional views need to be on a shorter line of sight. As a result, there has been increased effort to identify new image collection techniques that improve upon imaging resolution for these next generation neutron imaging systems, such as monolithic deuterated scintillators. This work details measurements performed at the Weapons Neutron Research Facility at Los Alamos National Laboratory that compares the radiographic abilities of the fiber scintillator with a monolithic scintillator, which may be featured in a future short line of sight neutron imaging systems.

Comparison of polystyrene scintillator fiber array and monolithic polystyrene for neutron imaging and radiography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simpson, R., E-mail: raspberry@lanl.gov; Cutler, T. E.; Danly, C. R.

The neutron imaging diagnostic at the National Ignition Facility has been operating since 2011 generating neutron images of deuterium-tritium (DT) implosions at peak compression. The current design features a scintillating fiber array, which allows for high imaging resolution to discern small-scale structure within the implosion. In recent years, it has become clear that additional neutron imaging systems need to be constructed in order to provide 3D reconstructions of the DT source and these additional views need to be on a shorter line of sight. As a result, there has been increased effort to identify new image collection techniques that improvemore » upon imaging resolution for these next generation neutron imaging systems, such as monolithic deuterated scintillators. This work details measurements performed at the Weapons Neutron Research Facility at Los Alamos National Laboratory that compares the radiographic abilities of the fiber scintillator with a monolithic scintillator, which may be featured in a future short line of sight neutron imaging systems.« less

Comparison of polystyrene scintillator fiber array and monolithic polystyrene for neutron imaging and radiography

NASA Astrophysics Data System (ADS)

Simpson, R.; Cutler, T. E.; Danly, C. R.; Espy, M. A.; Goglio, J. H.; Hunter, J. F.; Madden, A. C.; Mayo, D. R.; Merrill, F. E.; Nelson, R. O.; Swift, A. L.; Wilde, C. H.; Zocco, T. G.

2016-11-01

The neutron imaging diagnostic at the National Ignition Facility has been operating since 2011 generating neutron images of deuterium-tritium (DT) implosions at peak compression. The current design features a scintillating fiber array, which allows for high imaging resolution to discern small-scale structure within the implosion. In recent years, it has become clear that additional neutron imaging systems need to be constructed in order to provide 3D reconstructions of the DT source and these additional views need to be on a shorter line of sight. As a result, there has been increased effort to identify new image collection techniques that improve upon imaging resolution for these next generation neutron imaging systems, such as monolithic deuterated scintillators. This work details measurements performed at the Weapons Neutron Research Facility at Los Alamos National Laboratory that compares the radiographic abilities of the fiber scintillator with a monolithic scintillator, which may be featured in a future short line of sight neutron imaging systems.

Depletion of human serum albumin in embryo culture media for in vitro fertilization using monolithic columns with immobilized antibodies.

PubMed

Tarasova, Irina A; Lobas, Anna A; Černigoj, Urh; Solovyeva, Elizaveta M; Mahlberg, Barbara; Ivanov, Mark V; Panić-Janković, Tanja; Nagy, Zoltan; Pridatchenko, Marina L; Pungor, Andras; Nemec, Blaž; Vidic, Urška; Gašperšič, Jernej; Krajnc, Nika Lendero; Vidič, Jana; Gorshkov, Mikhail V; Mitulović, Goran

2016-09-01

Affinity depletion of abundant proteins such as HSA is an important stage in routine sample preparation prior to MS/MS analysis of biological samples with high range of concentrations. Due to the charge competition effects in electrospray ion source that results in discrimination of the low-abundance species, as well as limited dynamic range of MS/MS, restricted typically by three orders of magnitude, the identification of low-abundance proteins becomes a challenge unless the sample is depleted from high-concentration compounds. This dictates a need for developing efficient separation technologies allowing fast and automated protein depletion. In this study, we performed evaluation of a novel immunoaffinity-based Convective Interaction Media analytical columns (CIMac) depletion column with specificity to HSA (CIMac-αHSA). Because of the convective flow-through channels, the polymethacrylate CIMac monoliths afford flow rate independent binding capacity and resolution that results in relatively short analysis time compared with traditional chromatographic supports. Seppro IgY14 depletion kit was used as a benchmark to control the results of depletion. Bottom-up proteomic approach followed by label-free quantitation using normalized spectral indexes were employed for protein quantification in G1/G2 and cleavage/blastocyst in vitro fertilization culture media widely utilized in clinics for embryo growth in vitro. The results revealed approximately equal HSA level of 100 ± 25% in albumin-enriched fractions relative to the nondepleted samples for both CIMac-αHSA column and Seppro kit. In the albumin-free fractions concentrated 5.5-fold by volume, serum albumin was identified at the levels of 5-30% and 20-30% for the CIMac-αHSA and Seppro IgY14 spin columns, respectively. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Monolithic Solid Oxide Fuel Cell development

NASA Technical Reports Server (NTRS)

Myles, K. M.; Mcpheeters, C. C.

1989-01-01

The Monolithic Solid Oxide Fuel Cell (MSOFC) is an oxide-ceramic structure in which appropriate electronic and ionic conductors are fabricated in a honeycomb shape similar to a block of corrugated paperboard. These electronic and ionic conductors are arranged to provide short conduction paths to minimize resistive losses. The power density achievable with the MSOFC is expected to be about 8 kW/kg or 4 kW/L, at fuel efficienceis over 50 percent, because of small cell size and low resistive losses in the materials. The MSOFC operates in the range of 700 to 1000 C, at which temperatures rapid reform of hydrocarbon fuels is expected within the nickel-YSZ fuel channels. Tape casting and hot roll calendering are used to fabricate the MSOFC structure. The performance of the MSOFC has improved significantly during the course of development. The limitation of this system, based on materials resistance alone without interfacial resistances, is 0.093 ohm-sq cm area-specific resistance (ASR). The current typical performance of MSOFC single cells is characterized by ASRs of about 0.4 to 0.5 ohm-sq cm. With further development the ASR is expected to be reduced below 0.2 ohm-sq cm, which will result in power levels greater than 1.4 W/sq cm. The feasibility of the MSOFC concept was proven, and the performance was dramatically improved. The differences in thermal expansion coefficients and firing shrinkages among the fuel cell materials were minimized. As a result of good matching of these properties, the MSOFC structure was successfully fabricated with few defects, and the system shows excellent promise for development into a practical power source.

Biomolecule detection based on Si single-electron transistors for practical use

NASA Astrophysics Data System (ADS)

Nakajima, Anri; Kudo, Takashi; Furuse, Sadaharu

2013-07-01

Experimental and theoretical analyses demonstrated that ultra-sensitive biomolecule detection can be achieved using a Si single-electron transistor (SET). A multi-island channel structure was used to enable room-temperature operation. Coulomb oscillation increases transconductance without increasing channel width, which increases detection sensitivity to a charged target. A biotin-modified SET biosensor was used to detect streptavidin at a dilute concentration. In addition, an antibody-functionalized SET biosensor was used for immunodetection of prostate-specific antigen, demonstrating its suitability for practical use. The feasibility of ultra-sensitive detection of biomolecules for practical use by using a SET biosensor was clearly proven through this systematic study.

An improved ultra wideband channel model including the frequency-dependent attenuation for in-body communications.

PubMed

Khaleghi, A; Chávez-Santiago, R; Balasingham, I

2012-01-01

Ultra wideband (UWB) technology has big potential for applications in wireless body area networks (WBANs). The inherent characteristics of UWB signals make them suitable for the wireless interface of medical sensors. In particular, implanted medical wireless sensors for monitoring physiological parameters, automatic drug provision, etc. can benefit greatly from this ultra low power (ULP) interface. As with any other wireless technology, accurate knowledge of the channel is necessary for the proper design of communication systems. Only a few models that describe the radio propagation inside the human body have been published. Moreover, there is no comprehensive UWB in-body propagation model that includes the frequency-dependent attenuation. Hence, this paper extends a statistical model for UWB propagation channels inside the human chest in the 1-6 GHz frequency range by including the frequency-dependent attenuation. This is done by modeling the spectrum shape of distorted pulses at different depths inside the human chest. The distortion of the pulse was obtained through numerical simulations using a voxel representation of the human body. We propose a mathematical expression for the spectrum shape of the distorted pulses that act as a window function to reproduce the effects of frequency-dependent attenuation.

Non-invasive paper-based microfluidic device for ultra-low detection of urea through enzyme catalysis

NASA Astrophysics Data System (ADS)

Suresh, Vignesh; Qunya, Ong; Kanta, Bera Lakshmi; Yuh, Lee Yeong; Chong, Karen S. L.

2018-03-01

This work describes the design, fabrication and characterization of a paper-based microfluidic device for ultra-low detection of urea through enzyme catalysis. The microfluidic system comprises an entry port, a fluidic channel, a reaction zone and two electrodes (contacts). Wax printing was used to create fluidic channels on the surface of a chromatography paper. Pre-conceptualized designs of the fluidic channel are wax-printed on the paper substrate while the electrodes are screen-printed. The paper printed with wax is heated to cause the wax reflow along the thickness of the paper that selectively creates hydrophilic and hydrophobic zones inside the paper. Urease immobilized in the reaction zone catalyses urea into releasing ions and, thereby, generating a current flow between the electrodes. A measure of current with respect to time at a fixed potential enables the detection of urea. The methodology enabled urea concentration down to 1 pM to be detected. The significance of this work lies in the use of simple and inexpensive paper-based substrates to achieve detection of ultra-low concentrations of analytes such as urea. The process is non-invasive and employs a less cumbersome two-electrode assembly.

Phased charging and discharging in capacitive desalinatio

DOEpatents

Stadermann, Michael; Qu, Yatian; Santiago, Juan G.; Hemmatifar, Ali

2017-09-12

A system combines complete, ultra-thin cells into a monolithic and robust framework necessary for desalination applications which yields orders of magnitude faster desalination. The electrode pairs are located so that a flow of feed water flows through or around the electrode pairs with the flow perpendicular to sequentially applied electric potentials. The system is controlled to charge the series of electrode pairs sequentially or phased. That means the charging of the second electrode pair is delayed with regard to the charging of the first electrode pair and the charging of a third electrode pair is delayed with respect to the charging of the second electrode pair.

Data Acquisition System for Silicon Ultra Fast Cameras for Electron and Gamma Sources in Medical Applications (sucima Imager)

NASA Astrophysics Data System (ADS)

Czermak, A.; Zalewska, A.; Dulny, B.; Sowicki, B.; Jastrząb, M.; Nowak, L.

2004-07-01

The needs for real time monitoring of the hadrontherapy beam intensity and profile as well as requirements for the fast dosimetry using Monolithic Active Pixel Sensors (MAPS) forced the SUCIMA collaboration to the design of the unique Data Acquisition System (DAQ SUCIMA Imager). The DAQ system has been developed on one of the most advanced XILINX Field Programmable Gate Array chip - VERTEX II. The dedicated multifunctional electronic board for the detector's analogue signals capture, their parallel digital processing and final data compression as well as transmission through the high speed USB 2.0 port has been prototyped and tested.

Overview and Recent Accomplishments of Advanced Mirror Technology Development (AMTD) for Very Large Space Telescopes

NASA Technical Reports Server (NTRS)

Stahl, H. Philip

2013-01-01

AMTD uses a science-driven systems engineering approach to define & execute a long-term strategy to mature technologies necessary to enable future large aperture space telescopes. Because we cannot predict the future, we are pursuing multiple technology paths including monolithic & segmented mirrors. Assembled outstanding team from academia, industry & government; experts in science & space telescope engineering. Derived engineering specifications from science measurement needs & implementation constraints. Maturing 6 critical technologies required to enable 4 to 8 meter UVOIR space telescope mirror assemblies for both general astrophysics & ultra-high contrast exoplanet imaging. AMTD achieving all its goals & accomplishing all its milestones.

High performance diesel oxidation catalysts using ultra-low Pt loading on titania nanowire array integrated cordierite honeycombs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoang, Son; Lu, Xingxu; Tang, Wenxiang

High performance of an ultra-low Pt loading diesel oxidation catalyst can be achieved by using a combination of novel nano-array structured support, precise control of ultrafine active Pt particles, and an addition of H 2 as a promoter into the exhausts. Highly stable mesoporous rutile TiO 2 nano-array was uniformly grown on three-dimensional (3-D) cordierite honeycomb monoliths using a solvothermal synthesis. Atomic layer deposition was employed for precise dispersion of ultrafine Pt particles (0.95 ± 0.24 nm) on TiO 2 nano-array with a Pt loading of 1.1 g/ft 3. Despite low Pt loading, the Pt/TiO 2 nano-array catalyst shows impressivemore » low-temperature oxidation reactivity, with the conversion of CO and total hydrocarbon (THC) reaching 50% at 224 and 285 °C, respectively, in the clean diesel combustion (CDC) simulated exhaust conditions. The excellent activity is attributed to the unique nano-array structure that promotes gas-solid interaction and ultra-small Pt particle dispersion that increase surface Pt atoms. We also demonstrate that addition of more H 2 into the exhaust can lower light-off temperature for CO and THC by up to ~60 °C and ~30 °C, respectively.« less

High performance diesel oxidation catalysts using ultra-low Pt loading on titania nanowire array integrated cordierite honeycombs

DOE PAGES

Hoang, Son; Lu, Xingxu; Tang, Wenxiang; ...

2017-11-15

High performance of an ultra-low Pt loading diesel oxidation catalyst can be achieved by using a combination of novel nano-array structured support, precise control of ultrafine active Pt particles, and an addition of H 2 as a promoter into the exhausts. Highly stable mesoporous rutile TiO 2 nano-array was uniformly grown on three-dimensional (3-D) cordierite honeycomb monoliths using a solvothermal synthesis. Atomic layer deposition was employed for precise dispersion of ultrafine Pt particles (0.95 ± 0.24 nm) on TiO 2 nano-array with a Pt loading of 1.1 g/ft 3. Despite low Pt loading, the Pt/TiO 2 nano-array catalyst shows impressivemore » low-temperature oxidation reactivity, with the conversion of CO and total hydrocarbon (THC) reaching 50% at 224 and 285 °C, respectively, in the clean diesel combustion (CDC) simulated exhaust conditions. The excellent activity is attributed to the unique nano-array structure that promotes gas-solid interaction and ultra-small Pt particle dispersion that increase surface Pt atoms. We also demonstrate that addition of more H 2 into the exhaust can lower light-off temperature for CO and THC by up to ~60 °C and ~30 °C, respectively.« less

Ultra-low-loss and broadband mode converters in Si3N4 technology

NASA Astrophysics Data System (ADS)

Mu, Jinfeng; Dijkstra, Meindert; de Goede, Michiel; Yong, Yean-Sheng; García-Blanco, Sonia M.

2017-02-01

Si3N4 grown by low pressure chemical vapor deposition (LPCVD) on thermally oxidized silicon wafers is largely utilized for creating integrated photonic devices due to its ultra-low propagation loss and large transparency window (400 nm to 2350 nm). In this paper, an ultra-low-loss and broadband mode converter for monolithic integration of different materials onto the passive Si3N4 photonic technology platform is presented. The mode size converter is constructed with a vertically tapered Si3N4 waveguide that is then buried by a polymer or an Al2O3 waveguide. The influence of the various design parameters on the converter characteristics are investigated. Optimal designs are proposed, in which the thickness of the Si3N4 waveguide is tapered from 200 nm to 40 nm. The calculated losses of the mode converters at 976 nm and 1550 nm wavelengths are well below 0.1 dB for the Si3N4-polymer coupler and below 0.3 dB for the Si3N4-Al2O3 coupler. The preliminary experimental results show good agreement with the design values, indicating that the mode converters can be utilized for the low-loss integration of different materials.

Novel approach for chirp and output power compensation applied to a 40-Gbit/s EADFB laser integrated with a short SOA.

PubMed

Kobayashi, Wataru; Arai, Masakazu; Fujisawa, Takeshi; Sato, Tomonari; Ito, Toshio; Hasebe, Koichi; Kanazawa, Shigeru; Ueda, Yuta; Yamanaka, Takayuki; Sanjoh, Hiroaki

2015-04-06

We propose a novel approach for simultaneously controlling the chirp and increasing the output power of an EADFB laser by monolithically integrating a short-cavity SOA. We achieved a 40-Gbit/s 5-km SMF transmission at a wavelength of 1.55 μm by using an EADFB SOA with a lower power consumption than a stand-alone EADFB laser.

Implementation of real-time digital signal processing systems

NASA Technical Reports Server (NTRS)

Narasimha, M.; Peterson, A.; Narayan, S.

1978-01-01

Special purpose hardware implementation of DFT Computers and digital filters is considered in the light of newly introduced algorithms and IC devices. Recent work by Winograd on high-speed convolution techniques for computing short length DFT's, has motivated the development of more efficient algorithms, compared to the FFT, for evaluating the transform of longer sequences. Among these, prime factor algorithms appear suitable for special purpose hardware implementations. Architectural considerations in designing DFT computers based on these algorithms are discussed. With the availability of monolithic multiplier-accumulators, a direct implementation of IIR and FIR filters, using random access memories in place of shift registers, appears attractive. The memory addressing scheme involved in such implementations is discussed. A simple counter set-up to address the data memory in the realization of FIR filters is also described. The combination of a set of simple filters (weighting network) and a DFT computer is shown to realize a bank of uniform bandpass filters. The usefulness of this concept in arriving at a modular design for a million channel spectrum analyzer, based on microprocessors, is discussed.

System for the measurement of ultra-low stray light levels. [determining the adequacy of large space telescope systems

NASA Technical Reports Server (NTRS)

Wyman, C. L.; Griner, D. B.; Hurd, W. A.; Shelton, G. B.; Hunt, G. H.; Fannin, B. B.; Brealt, R. P.; Hawkins, C. A. (Inventor)

1978-01-01

An apparatus is described for measuring the effectiveness of stray light suppression light shields and baffle arrangements used in optical space experiments and large space telescopes. The light shield and baffle arrangement and a telescope model are contained in a vacuum chamber. A source of short, high-powered light energy illuminates portions of the light shield and baffle arrangement and reflects a portion of same to a photomultiplier tube by virtue of multipath scattering. The resulting signal is transferred to time-channel electronics timed by the firing of the high energy light source allowing time discrimination of the signal thereby enabling the light scattered and suppressed by the model to be distinguished from the walls and holders around the apparatus.

Location and Navigation with Ultra-Wideband Signals

DTIC Science & Technology

2012-06-07

Coherent vs. Noncoherent Combination 26 F Ranging with Multi-Band UWB Signals: Random Phase Ratation 29 F.1 MB-OFDM System Model...adopted to combine the channel information from subbands: the coherent combining and the noncoherent combining. For the coherent combining, estimates of...channel frequency response coefficients for all subbands are jointly used to estimate the time domain channel with Eq. (33). For the noncoherent

Overview and Recent Accomplishments of the Advanced Mirror Technology Development (AMTD) for Large Aperture UVOIR Space Telescopes Project

NASA Technical Reports Server (NTRS)

Stahl, H. Philip

2013-01-01

Per Astro2010, a new, larger UVO telescope is needed to answer fundamental scientific questions, such as: is there life on Earth-like exoplanets; how galaxies assemble stellar populations; how baryonic matter interacts with intergalactic medium; and how solar systems form and evolve. And, present technology is not mature enough to affordably build and launch any potential UVO concept. Advanced Mirror Technology Development (AMTD) is a funded SAT project. Our objective is to mature to TRL-6 the critical technologies needed to produce 4-m or larger flight-qualified UVOIR mirrors by 2018 so that a viable mission can be considered by the 2020 Decadal Review. AMTD uses a science-driven systems engineering approach. We mature technologies required to enable the highest priority science AND result in a high-performance low-cost low-risk system. To provide the science community with options, we are pursuing multiple technology paths. We have assembled an outstanding team from academia, industry, and government with extensive expertise in astrophysics and exoplanet characterization, and in the design/manufacture of monolithic and segmented space telescopes. One of our key accomplishments is that we have derived engineering specifications for advanced normal-incidence monolithic and segmented mirror systems needed to enable both general astrophysics and ultra-high contrast observations of exoplanets missions as a function of potential launch vehicle and its inherent mass and volume constraints. We defined and initiated a program to mature 6 key technologies required to fabricate monolithic and segmented space mirrors.

Single resonance monolithic Fabry-Perot filters formed by volume Bragg gratings and multilayer dielectric mirrors

NASA Astrophysics Data System (ADS)

Lumeau, Julien; Koc, Cihan; Mokhun, Oleksiy; Smirnov, Vadim; Lequime, Michel; Glebov, Leonid B.

2012-02-01

High efficiency reflecting volume Bragg gratings (VBGs) recorded in PTR glass plates have shown un-preceded performances that make them very good candidates for narrowband spectral filtering with sub-nanometer spectral widths. However, decreasing the bandwidth to value below 30-50 pm is very challenging as it requires increasing the thickness of the RBG to more than 15-20 mm. To overcome this limitation, we propose a new approach which is a monolithic Fabry-Perot cavity which consists from a reflecting VBG with a multilayer dielectric mirror (MDM) deposited on its surface. A VBG with a grating vector perpendicular to its surface and a MDM produce a Fabry-Perot resonator with a single transmission band inside of the reflection spectrum of the VBG. We present a theoretical description of this new class of filters that allow achieving a single ultra-narrowband resonance associated with several hundred nanometers rejection band. Then we show the methods for designing and fabricating such filter. Finally, we present the steps that we followed in order to fabricate a first prototype for 852 nm and 1062 nm region that demonstrates a 30 pm bandwidth, 90+% transmission at resonance and a good agreement with theoretical simulation.

Novel ultra-short and ultra-broadband polarization beam splitter based on a bent directional coupler.

PubMed

Dai, Daoxin; Bowers, John E

2011-09-12

A novel ultra-short polarization beam splitter (PBS) based on a bent directional coupler is proposed by utilizing the evanescent coupling between two bent optical waveguides with different core widths. For the bent directional coupler, there is a significant phase-mismatch for TE polarization while the phase-matching condition is satisfied for TM polarization. Therefore, the TM polarized light can be coupled from the narrow input waveguide to the adjacent wide waveguide while the TE polarization goes through the coupling region without significant coupling. An ultra-short (<10 μm-long) PBS is designed based on silicon-on-insulator nanowires and the length of the bent coupling region is as small as 4.5 μm while the gap width is chosen as 200 nm (large enough to simplify the fabrication). Numerical simulations show that the present PBS has a good fabrication tolerance for the variation of the waveguide width (more than ± 60 nm) and a very broad band (~200 nm) for an extinction ratio of >10 dB.

Method for laser welding ultra-thin metal foils

DOEpatents

Pernicka, J.C.; Benson, D.K.; Tracy, C.E.

1996-03-26

A method for simultaneously cutting and welding ultra-thin foils having a thickness of less than 0.002 inches wherein two ultra-thin films are stacked and clamped together. A pulsed laser such as of the Neodymium: YAG type is provided and the beam of the laser is directed onto the stacked films to cut a channel through the films. The laser is moved relative to the stacked foils to cut the stacked foils at successive locations and to form a plurality of connected weld beads to form a continuous weld. 5 figs.

Method for laser welding ultra-thin metal foils

DOEpatents

Pernicka, John C.; Benson, David K.; Tracy, C. Edwin

1996-01-01

A method for simultaneously cutting and welding ultra-thin foils having a thickness of less than 0.002 inches wherein two ultra-thin films are stacked and clamped together. A pulsed laser such as of the Neodymium: YAG type is provided and the beam of the laser is directed onto the stacked films to cut a channel through the films. The laser is moved relative to the stacked foils to cut the stacked foils at successive locations and to form a plurality of connected weld beads to form a continuous weld.

Monolithic barrier-all-around high electron mobility transistor with planar GaAs nanowire channel.

PubMed

Miao, Xin; Zhang, Chen; Li, Xiuling

2013-06-12

High-quality growth of planar GaAs nanowires (NWs) with widths as small as 35 nm is realized by comprehensively mapping the parameter space of group III flow, V/III ratio, and temperature as the size of the NWs scales down. Using a growth mode modulation scheme for the NW and thin film barrier layers, monolithically integrated AlGaAs barrier-all-around planar GaAs NW high electron mobility transistors (NW-HEMTs) are achieved. The peak extrinsic transconductance, drive current, and effective electron velocity are 550 μS/μm, 435 μA/μm, and ~2.9 × 10(7) cm/s, respectively, at 2 V supply voltage with a gate length of 120 nm. The excellent DC performance demonstrated here shows the potential of this bottom-up planar NW technology for low-power high-speed very-large-scale-integration (VLSI) circuits.

Advanced InSb monolithic Charge Coupled Infrared Imaging Devices (CCIRID)

NASA Technical Reports Server (NTRS)

Koch, T. L.; Thom, R. D.; Parrish, W. D.

1981-01-01

The continued development of monolithic InSb charge coupled infrared imaging devices (CCIRIDs) is discussed. The processing sequence and structural design of 20-element linear arrays are discussed. Also, results obtained from radiometric testing of the 20-element arrays using a clamped sample-and-hold output circuit are reported. The design and layout of a next-generation CCIRID chip are discussed. The major devices on this chip are a 20 by 16 time-delay-and-integration (TDI) area array and a 100-element linear imaging array. The development of a process for incorporating an ion implanted S(+) planar channel stop into the CCIRID structure and the development of a thin film transparent photogate are also addressed. The transparent photogates will increase quantum efficiency to greater than 70% across the 2.5 to 5.4 micrometer spectral region in future front-side illuminated CCIRIDs.

A monolithic glass chip for active single-cell sorting based on mechanical phenotyping.

PubMed

Faigle, Christoph; Lautenschläger, Franziska; Whyte, Graeme; Homewood, Philip; Martín-Badosa, Estela; Guck, Jochen

2015-03-07

The mechanical properties of biological cells have long been considered as inherent markers of biological function and disease. However, the screening and active sorting of heterogeneous populations based on serial single-cell mechanical measurements has not been demonstrated. Here we present a novel monolithic glass chip for combined fluorescence detection and mechanical phenotyping using an optical stretcher. A new design and manufacturing process, involving the bonding of two asymmetrically etched glass plates, combines exact optical fiber alignment, low laser damage threshold and high imaging quality with the possibility of several microfluidic inlet and outlet channels. We show the utility of such a custom-built optical stretcher glass chip by measuring and sorting single cells in a heterogeneous population based on their different mechanical properties and verify sorting accuracy by simultaneous fluorescence detection. This offers new possibilities of exact characterization and sorting of small populations based on rheological properties for biological and biomedical applications.

A Monolithic Electrochemical Micro Seismic Sensor Capable of Monitoring Three-Dimensional Vibrations

PubMed Central

Chen, Lianhong; Sun, Zhenyuan; Li, Guanglei; Chen, Deyong; Wang, Junbo

2018-01-01

A monolithic electrochemical micro seismic sensor capable of monitoring three-axial vibrations was proposed in this paper. The proposed micro sensor mainly consisted of four sensing units interconnected within flow channels and by interpreting the voltage outputs of the sensing units, vibrations with arbitrary directions can be quantified. The proposed seismic sensors are fabricated based on MEMS technologies and characterized, which produced sensitivities along x, y, and z axes as 2473.2 ± 184.5 V/(m/s), 2261.7 ± 119.6 V/(m/s), and 3480.7 ± 417.2 V/(m/s) at 30 Hz. In addition, the vibrations in x-y, x-z, and y-z planes were applied to the developed seismic sensors, leading to comparable monitoring results after decoupling calculations with the input velocities. Furthermore, the results have shown its feasibilities for seismic data recording. PMID:29614720

Monolithic microwave integrated circuit water vapor radiometer

NASA Technical Reports Server (NTRS)

Sukamto, L. M.; Cooley, T. W.; Janssen, M. A.; Parks, G. S.

1991-01-01

A proof of concept Monolithic Microwave Integrated Circuit (MMIC) Water Vapor Radiometer (WVR) is under development at the Jet Propulsion Laboratory (JPL). WVR's are used to remotely sense water vapor and cloud liquid water in the atmosphere and are valuable for meteorological applications as well as for determination of signal path delays due to water vapor in the atmosphere. The high cost and large size of existing WVR instruments motivate the development of miniature MMIC WVR's, which have great potential for low cost mass production. The miniaturization of WVR components allows large scale deployment of WVR's for Earth environment and meteorological applications. Small WVR's can also result in improved thermal stability, resulting in improved calibration stability. Described here is the design and fabrication of a 31.4 GHz MMIC radiometer as one channel of a thermally stable WVR as a means of assessing MMIC technology feasibility.

Monolithic optofluidic ring resonator lasers created by femtosecond laser nanofabrication.

PubMed

Chandrahalim, Hengky; Chen, Qiushu; Said, Ali A; Dugan, Mark; Fan, Xudong

2015-05-21

We designed, fabricated, and characterized a monolithically integrated optofluidic ring resonator laser that is mechanically, thermally, and chemically robust. The entire device, including the ring resonator channel and sample delivery microfluidics, was created in a block of fused-silica glass using a 3-dimensional femtosecond laser writing process. The gain medium, composed of Rhodamine 6G (R6G) dissolved in quinoline, was flowed through the ring resonator. Lasing was achieved at a pump threshold of approximately 15 μJ mm(-2). Detailed analysis shows that the Q-factor of the optofluidic ring resonator is 3.3 × 10(4), which is limited by both solvent absorption and scattering loss. In particular, a Q-factor resulting from the scattering loss can be as high as 4.2 × 10(4), suggesting the feasibility of using a femtosecond laser to create high quality optical cavities.

Selective laser melting of hypereutectic Al-Si40-powder using ultra-short laser pulses

NASA Astrophysics Data System (ADS)

Ullsperger, T.; Matthäus, G.; Kaden, L.; Engelhardt, H.; Rettenmayr, M.; Risse, S.; Tünnermann, A.; Nolte, S.

2017-12-01

We investigate the use of ultra-short laser pulses for the selective melting of Al-Si40-powder to fabricate complex light-weight structures with wall sizes below 100 μ {m} combined with higher tensile strength and lower thermal expansion coefficient in comparison to standard Al-Si alloys. During the cooling process using conventional techniques, large primary silicon particles are formed which impairs the mechanical and thermal properties. We demonstrate that these limitations can be overcome using ultra-short laser pulses enabling the rapid heating and cooling in a non-thermal equilibrium process. We analyze the morphology characteristics and micro-structures of single tracks and thin-walled structures depending on pulse energy, repetition rate and scanning velocity utilizing pulses with a duration of 500 {fs} at a wavelength of 1030 {nm}. The possibility to specifically change and optimize the microstructure is shown.

A new method to calculate the beam charge for an integrating current transformer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu Yuchi; Han Dan; Zhu Bin

2012-09-15

The integrating current transformer (ICT) is a magnetic sensor widely used to precisely measure the charge of an ultra-short-pulse charged particle beam generated by traditional accelerators and new laser-plasma particle accelerators. In this paper, we present a new method to calculate the beam charge in an ICT based on circuit analysis. The output transfer function shows an invariable signal profile for an ultra-short electron bunch, so the function can be used to evaluate the signal quality and calculate the beam charge through signal fitting. We obtain a set of parameters in the output function from a standard signal generated bymore » an ultra-short electron bunch (about 1 ps in duration) at a radio frequency linear electron accelerator at Tsinghua University. These parameters can be used to obtain the beam charge by signal fitting with excellent accuracy.« less

Ultra-short wavelength operation in Thulium-doped silica fiber laser with bidirectional pumping

NASA Astrophysics Data System (ADS)

Xiao, Xusheng; Guo, Haitao; Yan, Zhijun; Wang, Hushan; Xu, Yantao; Lu, Min; Wang, Yishan; Peng, Bo

2017-02-01

An ultra-short wavelength operation of Tm-doped all fiber laser based on fiber Bragg gratings (FBGs) was developed. A bi-directional pump configuration for the ultra-short wavelength operation was designed and investigated for the first time. the laser yielded 3.15W of continuous-wave output at 1706.75nm with a narrow-linewidth of 50pm and a maximum slope efficiency of 42.1%. The dependencies of the slope efficiencies and pump threshold of the laser versus the length of active fiber and reflectivity of the output mirror (FBG) were investigated in detail. An experimental comparative study between two Thulium-doped fiber lasers (TDFLs) with two different pumping configuration(forward unidirectional pumping and bidirectional pumping) was presented. It is indisputable that the development of 1.7μm silicate fiber lasers with Watt-level output power open up a number of heart-stirring and tempting application windows.

The Ultracam Story

NASA Astrophysics Data System (ADS)

Leberl, F.; Gruber, M.; Ponticelli, M.; Wiechert, A.

2012-07-01

The UltraCam-project created a novel Large Format Digital Aerial Camera. It was inspired by the ISPRS Congress 2000 in Amsterdam. The search for a promising imaging idea succeeded in May 2001, defining a tiling approach with multiple lenses and multiple area CCD arrays to assemble a seamless and geometrically stable monolithic photogrammetric aerial large format image. First resources were spent on the project in September 2011. The initial UltraCam-D was announced and demonstrated in May 2003. By now the imaging principle has resulted in a 4th generation UltraCam Eagle, increasing the original swath width from 11,500 pixels to beyond 20,000. Inspired by the original imaging principle, alternatives have been investigated, and the UltraCam-G carries the swath width even further, namely to a frame image with nearly 30,000 pixels, however, with a modified tiling concept and optimized for orthophoto production. We explain the advent of digital aerial large format imaging and how it benefits from improvements in computing technology to cope with data flows at a rate of 3 Gigabits per second and a need to deal with Terabytes of imagery within a single aerial sortie. We also address the many benefits of a transition to a fully digital workflow with a paradigm shift away from minimizing a project's number of aerial photographs and towards maximizing the automation of photogrammetric workflows by means of high redundancy imaging strategies. The instant gratification from near-real-time aerial triangulations and dense image matching has led to a reassessment of the value of photogrammetric point clouds to successfully compete with direct point cloud measurements by LiDAR.

Treating a natural outbreak of columnaris in channel catfish with copper sulfate and potassium permanganate

USDA-ARS?s Scientific Manuscript database

An F. Columnare-exclusive epizootic occurred in fingerling channel catfish (Ictalurus punctatus) during normal tank culture practices at SNARC. Fish were transferred to the ultra low-flow system and 2.1 mg/L copper sulfate or 3 mg/L potassium permanganate was administered; an untreated control was ...

Shock-induced compaction of nanoparticle layers into nanostructured coating

NASA Astrophysics Data System (ADS)

Mayer, Alexander E.; Ebel, Andrei A.

2017-10-01

A new process of shock wave consolidation of nanoparticles into a nanocrystalline coating is theoretically considered. In the proposed scheme, the nanoparticle layers, which are attached to the substrate surface by adhesion, are compacted by plane ultra-short shock waves coming from the substrate. The initial adhesion is self-arisen at any contact between the nanoparticles without a pre-compression. The absence of the nanoparticle ejections due to the shock wave action is connected with the strong adhesive forces, which allow nanoparticles to be attached to each other and to substrate while they are being compacted; this should be valid for small enough nanoparticles. Severe plastic deformation of the nanoparticles and the increased temperature due to collapse of voids between them facilitate their compaction into the monolithic nanocrystalline layer. We consider the examples of Cu and Ni nanoparticles on Al substrate using molecular dynamic simulations. We show the efficiency of the action of multiple shock waves with the duration in the range 2-20 ps and the amplitude in the range 4-12 GPa for sequential layerwise compaction of nanoparticles. A series of shock waves can be created by a repetitive powerful pulsed laser irradiation of the opposite surface of the substrate. The method offers the challenge for the formation of nanostructured coatings of various compositions. The thickness of the compacted nanocrystalline coating can be locally varied and controlled by the number of acting pulses.

Sensitization of ultra-long-range excited-state electron transfer by energy transfer in a polymerized film

PubMed Central

Ito, Akitaka; Stewart, David J.; Fang, Zhen; Brennaman, M. Kyle; Meyer, Thomas J.

2012-01-01

Distance-dependent energy transfer occurs from the Metal-to-Ligand Charge Transfer (MLCT) excited state to an anthracene-acrylate derivative (Acr-An) incorporated into the polymer network of a semirigid poly(ethyleneglycol)dimethacrylate monolith. Following excitation, to Acr-An triplet energy transfer occurs followed by long-range, Acr-3An—Acr-An → Acr-An—Acr-3An, energy migration. With methyl viologen dication (MV2+) added as a trap, Acr-3An + MV2+ → Acr-An+ + MV+ electron transfer results in sensitized electron transfer quenching over a distance of approximately 90 Å. PMID:22949698

Monolithic InP strictly non-blocking 8×8 switch for high-speed WDM optical interconnection.

PubMed

Kwack, Myung-Joon; Tanemura, Takuo; Higo, Akio; Nakano, Yoshiaki

2012-12-17

A strictly non-blocking 8 × 8 switch for high-speed WDM optical interconnection is realized on InP by using the phased-array scheme for the first time. The matrix switch architecture consists of over 200 functional devices such as star couplers, phase-shifters and so on without any waveguide cross-section. We demonstrate ultra-broad optical bandwidth covering the entire C-band through several Input/Output ports combination with extinction ratio performance of more than 20dB. Also, nanoseconds reconfiguration time was successfully achieved by dynamic switching experiment. Error-free transmission was verified for 40-Gbps (10-Gbps × 4ch) WDM signal.

Monolithic photonic integration for visible and short near-infrared wavelengths: technologies and platforms for bio and life science applications

NASA Astrophysics Data System (ADS)

Porcel, Marco A. G.; Artundo, Iñigo; Domenech, J. David; Geuzebroek, Douwe; Sunarto, Rino; Hoofman, Romano

2018-04-01

This tutorial aims to provide a general overview on the state-of-the-art of photonic integrated circuits (PICs) in the visible and short near-infrared (NIR) wavelength ranges, mostly focusing in silicon nitride (SiN) substrates, and a guide to the necessary steps in the design toward the fabrication of such PICs. The focus is put on bio- and life sciences, given the adequacy and, thus, a large number of applications in this field.

Coupling of Ultrafast LC with Mass Spectrometry by DESI

NASA Astrophysics Data System (ADS)

Cai, Yi; Liu, Yong; Helmy, Roy; Chen, Hao

2014-10-01

Recently we reported a desorption electrospray ionization (DESI) interface to combine liquid chromatography (LC) with mass spectrometry (MS) using a new LC eluent splitting strategy through a tiny orifice on LC capillary tube [ J. Am. Soc. Mass Spectrom. 25, 286 (2014)]. The interface introduces negligible dead volume and back pressure, thereby allowing "near real-time" MS detection, fast LC elution, and online MS-directed purification. This study further evaluates the LC/DESI-MS performance with focus of using ultra-fast LC. Using a monolithic C18 column, metabolites in urine can be separated within 1.6 min and can be online collected for subsequent structure elucidation (e.g., by NMR, UV, IR) in a recovery yield up to 99%. Using a spray solvent with alkaline pH, negative ions could be directly generated for acidic analytes (e.g., ibuprofen) in acidic LC eluent by DESI, offering a novel protocol to realize "wrong-way around" ionization for LC/MS analysis. In addition, DESI-MS is found to be compatible with ultra-performance liquid chromatography (UPLC) for the first time.

Ultra-doped n-type germanium thin films for sensing in the mid-infrared

PubMed Central

Prucnal, Slawomir; Liu, Fang; Voelskow, Matthias; Vines, Lasse; Rebohle, Lars; Lang, Denny; Berencén, Yonder; Andric, Stefan; Boettger, Roman; Helm, Manfred; Zhou, Shengqiang; Skorupa, Wolfgang

2016-01-01

A key milestone for the next generation of high-performance multifunctional microelectronic devices is the monolithic integration of high-mobility materials with Si technology. The use of Ge instead of Si as a basic material in nanoelectronics would need homogeneous p- and n-type doping with high carrier densities. Here we use ion implantation followed by rear side flash-lamp annealing (r-FLA) for the fabrication of heavily doped n-type Ge with high mobility. This approach, in contrast to conventional annealing procedures, leads to the full recrystallization of Ge films and high P activation. In this way single crystalline Ge thin films free of defects with maximum attained carrier concentrations of 2.20 ± 0.11 × 1020 cm−3 and carrier mobilities above 260 cm2/(V·s) were obtained. The obtained ultra-doped Ge films display a room-temperature plasma frequency above 1,850 cm−1, which enables to exploit the plasmonic properties of Ge for sensing in the mid-infrared spectral range. PMID:27282547

Characteristics of Various Photodiode Structures in CMOS Technology with Monolithic Signal Processing Electronics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mukhopadhyay, Sourav; Chandratre, V. B.; Sukhwani, Menka

2011-10-20

Monolithic optical sensor with readout electronics are needed in optical communication, medical imaging and scintillator based gamma spectroscopy system. This paper presents the design of three different CMOS photodiode test structures and two readout channels in a commercial CMOS technology catering to the need of nuclear instrumentation. The three photodiode structures each of 1 mm{sup 2} with readout electronics are fabricated in 0.35 um, 4 metal, double poly, N-well CMOS process. These photodiode structures are based on available P-N junction of standard CMOS process i.e. N-well/P-substrate, P+/N-well/P-substrate and inter-digitized P+/N-well/P-substrate. The comparisons of typical characteristics among three fabricated photo sensorsmore » are reported in terms of spectral sensitivity, dark current and junction capacitance. Among the three photodiode structures N-well/P-substrate photodiode shows higher spectral sensitivity compared to the other two photodiode structures. The inter-digitized P+/N-well/P-substrate structure has enhanced blue response compared to N-well/P-substrate and P+/N-well/P-substrate photodiode. Design and test results of monolithic readout electronics, for three different CMOS photodiode structures for application related to nuclear instrumentation, are also reported.« less

High-pulse-energy passively Q-switched quasi-monolithic microchip lasers operating in the sub-100-ps pulse regime.

PubMed

Nodop, D; Limpert, J; Hohmuth, R; Richter, W; Guina, M; Tünnermann, A

2007-08-01

We present passively Q-switched microchip lasers with items bonded by spin-on-glass glue. Passive Q-switching is obtained by a semiconductor saturable absorber mirror. The laser medium is a Nd:YVO(4) crystal. These lasers generate pulse peak powers up to 20 kW at a pulse duration as short as 50 ps and pulse repetition rates of 166 kHz. At 1064 nm, a linear polarized transversal and longitudinal single-mode beam is emitted. To the best of our knowledge, these are the shortest pulses in the 1 microJ energy range ever obtained with passively Q-switched microchip lasers. The quasi-monolithic setup ensures stable and reliable performance.

On Integration and Validation of a Very Low Complexity ATC UWB System for Muscle Force Transmission.

PubMed

Sapienza, Stefano; Crepaldi, Marco; Motto Ros, Paolo; Bonanno, Alberto; Demarchi, Danilo

2016-04-01

The thresholding of Surface ElectroMyoGraphic (sEMG) signals, i.e., Average Threshold Crossing (ATC) technique, reduces the amount of data to be processed enabling circuit complexity reduction and low power consumption. This paper investigates the lowest level of complexity reachable by an ATC system through measurements and in-vivo experiments with an embedded prototype for wireless force transmission, based on asynchronous Impulse-Radio Ultra Wide Band (IR-UWB). The prototype is composed by the acquisition unit, a wearable PCB 23 × 34 mm, which includes a full custom IC integrating a UWB transmitter (chip active silicon area 0.016 mm(2), 1 mW power consumption), and the receiver. The system is completely asynchronous, it acquires a differential sEMG signal, generates the ATC events and triggers a 3.3 GHz IR-UWB transmission. ATC robustness relaxes filters constraints: two passive first order filters have been implemented, bandwidth from 10 Hz up to 1 kHz. Energy needed for the single pulse generation is 30 pJ while the whole PCB consumes 5.65 mW. The pulses radiated by the acquisition unit TX are received by a short-range and low complexity threshold-based 130 nm CMOS IR-UWB receiver with an Ultra Low Power (ULP) baseband unit capable of robustly receiving generic quasi-digital pulse sequences. The acquisition unit have been tested with 10 series of in vivo isometric and isotonic contractions, while the transmission channel with over-the-air and cable measurements obtained with a couple of planar monopole antennas and an integrated 0.004 mm(2) transmitter, the same used for the acquisition unit, with realistic channel conditions. The entire system, acquisition unit and receiver, consumes 15.49 mW.

Transport and fate of estrogenic hormones in slurry-treated soil monoliths.

PubMed

Laegdsmand, Mette; Andersen, Henrik; Jacobsen, Ole Hørbye; Halling-Sørensen, Bent

2009-01-01

The naturally occurring hormones, such as 17-beta-estradiol, 17-alpha-estradiol, and estrone, present in livestock manure may have detrimental environmental effects if released into surface waters. In areas where manure application is intensive, estrogens have been found in surface waters in concentrations known to affect the endocrine system of fish and amphibians. How the estrogens reach the surface waters is unclear. To investigate whether leaching through the soil profile plays a significant role, we conducted leaching experiments on intact soil cores. Lysimeter soil monoliths (60 cm in diameter and 100 cm long) were excavated from two sites in Denmark (one loamy and one sandy soil). The soil monoliths were treated with pig slurry containing estrogenic hormones and amended with an estrogen tracer (17-alpha-ethinylestradiol) and a conservative tracer (bromide). 17-alpha-ethinylestradiol is a synthetic analog of 17-beta-estradiol with sorption characteristics and molecular structure similar to those of the naturally occurring estrogens in slurry. The monoliths were exposed to a short-term irrigation event (12 h) followed by a long-term semi-field experiment (16 wk), during which leaching of natural estrogens and tracers was followed. Estrogens from slurry were transported to a depth of 1 m in loamy soil and sandy soil. The estrogen concentrations in the leachate were at a level known to affect the endocrine system of aquatic organisms.

Detailed Experimental Study of Ion Acceleration by Interaction of an Ultra-Short Intense Laser with an Underdense Plasma

PubMed Central

Kahaly, S.; Sylla, F.; Lifschitz, A.; Flacco, A.; Veltcheva, M.; Malka, V.

2016-01-01

Ion acceleration from intense (Iλ2 > 1018 Wcm−2 μm2) laser-plasma interaction is experimentally studied within a wide range of He gas densities. Focusing an ultrashort pulse (duration  ion plasma period) on a newly designed submillimetric gas jet system, enabled us to inhibit total evacuation of electrons from the central propagation channel reducing the radial ion acceleration associated with ponderomotive Coulomb explosion, a mechanism predominant in the long pulse scenario. New ion acceleration mechanism have been unveiled in this regime leading to non-Maxwellian quasi monoenergetic features in the ion energy spectra. The emitted nonthermal ion bunches show a new scaling of the ion peak energy with plasma density. The scaling identified in this new regime differs from previously reported studies. PMID:27531755

Standard measurement procedures for the characterization of fs-laser optical components

NASA Astrophysics Data System (ADS)

Starke, Kai; Ristau, Detlev; Welling, Herbert

2003-05-01

Ultra-short pulse laser systems are considered as promising tools in the fields of precise micro-machining and medicine applications. In the course of the development of reliable table top laser systems, a rapid growth of ultra-short pulse applications could be observed during the recent years. The key for improving the performance of high power laser systems is the quality of the optical components concerning spectral characteristics, optical losses and the power handling capability. In the field of ultra-short pulses, standard measurement procedures in quality management have to be validated in respect to effects induced by the extremely high peak power densities. The present work, which is embedded in the EUREKA-project CHOCLAB II, is predominantly concentrated on measuring the multiple-pulse LIDT (ISO 11254-2) in the fs-regime. A measurement facility based on a Ti:Sapphire-CPA system was developed to investigate the damage behavior of optical components. The set-up was supplied with an improved pulse energy detector discriminating the influence of pulse-to-pulse energy fluctuations on the incidence of damage. Aditionally, a laser-calorimetric measurement facility determining the absorption (ISO 11551) utilizing a fs-Ti:Sapphire laser was accomplished. The investigation for different pulse durations between 130 fs and 1 ps revealed a drastic increase of absorption in titania coatings for ultra-short pulses.

Behavior of short silica monolithic columns in high pressure gas chromatography.

PubMed

Maniquet, Adrien; Bruyer, Nicolas; Raffin, Guy; Baco-Antoniali, Franck; Demesmay, Claire; Dugas, Vincent; Randon, Jérôme

2016-08-19

In order to analyze light hydrocarbons mixtures with silica monolithic columns, a conventional gas chromatograph was modified to work with carrier gas pressure as high as 60bar. To understand hydrodynamic flow and retention with short columns (less than 30cm), special attention was required due to the temperature difference between the oven area and the FID detector which contain a significant length of the column. Efficiency and selectivity using various carrier gases (helium, nitrogen and carbon dioxide) at different inlet pressure for different oven temperature were studied. Carrier gas nature was a very significant parameter: on one side, linked to adsorption mechanism for gases like nitrogen and carbon dioxide onto the stationary phase modifying retention and selectivity, on the other side in relation to the minimum theoretical plate height which was as low as 15μm (66 000 platem(-1)) using carbon dioxide as carrier gas. The chromatographic system was then used to separate methane, ethane, ethylene, acetylene, propane, cyclopropane, and butane in less than 30s. Copyright © 2016 Elsevier B.V. All rights reserved.

Theory and simulation of multi-channel interference (MCI) widely tunable lasers.

PubMed

Chen, Quanan; Lu, Qiaoyin; Guo, Weihua

2015-07-13

A novel design of an InP-based monolithic widely tunable laser, multi-channel interference (MCI) laser, is proposed and presented for the first time. The device is comprised of a gain section, a common phase section and a multi-channel interference section. The multi-channel interference section contains a 1x8 splitter based on cascaded 1 × 2 multi-mode interferometers (MMIs) and eight arms with unequal length difference. The rear part of each arm is integrated with a one-port multi-mode interference reflector (MIR). Mode selection of the MCI laser is realized by the constructive interference of the lights reflected back by the eight arms. Through optimizing the arm length difference, a tuning range of more than 40 nm covering the whole C band, a threshold current around 11.5 mA and an side-mode-suppression-ratio (SMSR) up to 48 dB have been predicted for this widely tunable laser. Detailed design principle and numerical simulation results are presented.

Fabrication of 4H-SiC n-channel IGBTs with ultra high blocking voltage

NASA Astrophysics Data System (ADS)

Yang, Xiaolei; Tao, Yonghong; Yang, Tongtong; Huang, Runhua; Song, Bai

2018-03-01

Owing to the conductivity modulation of silicon carbide (SiC) bipolar devices, n-channel insulated gate bipolar transistors (n-IGBTs) have a significant advantage over metal oxide semiconductor field effect transistors (MOSFETs) in ultra high voltage (UHV) applications. In this paper, backside grinding and laser annealing process were carried out to fabricate 4H-SiC n-IGBTs. The thickness of a drift layer was 120 μm, which was designed for a blocking voltage of 13 kV. The n-IGBTs carried a collector current density of 24 A/cm2 at a power dissipation of 300 W/cm2 when the gate voltage was 20 V, with a differential specific on-resistance of 140 mΩ·cm2.

Remarkably high mobility ultra-thin-film metal-oxide transistor with strongly overlapped orbitals

NASA Astrophysics Data System (ADS)

Wei Shih, Chen; Chin, Albert; Fu Lu, Chun; Fang Su, Wei

2016-01-01

High mobility channel thin-film-transistor (TFT) is crucial for both display and future generation integrated circuit. We report a new metal-oxide TFT that has an ultra-thin 4.5 nm SnO2 thickness for both active channel and source-drain regions, very high 147 cm2/Vs field-effect mobility, high ION/IOFF of 2.3 × 107, small 110 mV/dec sub-threshold slope, and a low VD of 2.5 V for low power operation. This mobility is already better than chemical-vapor-deposition grown multi-layers MoS2 TFT. From first principle quantum-mechanical calculation, the high mobility TFT is due to strongly overlapped orbitals.

Remarkably high mobility ultra-thin-film metal-oxide transistor with strongly overlapped orbitals

PubMed Central

Wei Shih, Chen; Chin, Albert; Fu Lu, Chun; Fang Su, Wei

2016-01-01

High mobility channel thin-film-transistor (TFT) is crucial for both display and future generation integrated circuit. We report a new metal-oxide TFT that has an ultra-thin 4.5 nm SnO2 thickness for both active channel and source-drain regions, very high 147 cm2/Vs field-effect mobility, high ION/IOFF of 2.3 × 107, small 110 mV/dec sub-threshold slope, and a low VD of 2.5 V for low power operation. This mobility is already better than chemical-vapor-deposition grown multi-layers MoS2 TFT. From first principle quantum-mechanical calculation, the high mobility TFT is due to strongly overlapped orbitals. PMID:26744240

The method for scanning reshaping the spectrum of chirped laser pulse based on the quadratic electro-optic effects

NASA Astrophysics Data System (ADS)

Ye, Rong; Yin, Ming; Wu, Xianyun; Tan, Hang

2017-10-01

T A new method for scanning reshaping the spectrum of chirped laser pulse based on quadratic electro-optic effects is proposed. The scanning reshaping scheme with a two-beam interference system is designed and the spectrum reshaping properties are analyzed theoretically. For the Gaussian chirped laser pulse with central wavelength λ0=800nm, nearly flat-topped spectral profiles with wider bandwidth is obtained with the proposed scanning reshaping method, which is beneficial to compensate for the gain narrowing effect in CPA and OPCPA. Further numerical simulations show that the reshaped spectrum is sensitive to the time-delay and deviation of the voltage applied to the crystal. In order to avoid narrowing or distorting the reshaped spectrum pointing to target, it is necessary to reduce the unfavorable deviations. With the rapid and wide applications of ultra-short laser pulse supported by some latter research results including photo-associative formation of ultra-cold molecules from ultra-cold atoms[1-3], laser-induced communications[4], capsule implosions on the National Ignition Facility(NIF)[5-6], the control of the temporal and spectral profiles of laser pulse is very important and urgently need to be addressed. Generally, the control of the pulse profiles depends on practical applications, ranging from femtosecond and picosecond to nanosecond. For instance, the basic shaping setup is a Fourier transform system for ultra-short laser pulse. The most important element is a spatially patterned mask which modulates the phase or amplitude, or sometimes the polarization after the pulse is decomposed into its constituent spectral components by usually a grating and a lens[7]. One of the generation techniques of ultra-short laser pulse is the chirped pulse amplifications(CPA), which brings a new era of development for high energy and high peak intensity ultra-short laser pulse, proposed by D. Strcik and G. Mourou from the chirping radar technology in microwave region since 1985[8]. The other generation technique of ultra-short pulse is the optical parametric chirped pulse amplification(OPCPA) invented by Dubietis et al. in 1992, which combined the respective superiorities of CPA and optical parametric amplification(OPA). However, there are disadvantages for the both technologies such as gain narrowing, gain saturation effects, and even spectrum shift. The first one among the three is the most significant which narrows the spectrum after amplification so that it limits the minimum durations of ultra-short laser pulse. This paper proposed a approach for scanning reshaping the spectrum of chirped laser pulse to compensate for the gain narrowing effect, according to the characteristics of the chirped laser pulse, i.e. the frequency varies with time linearly. The spectral characteristics of the scanning reshaping was analyzed quantitatively. Furthermore, the influence of the time-delay and deviation of the controlling voltage employed on the electro-optic crystal on the reshaped spectrum was also been discussed in detail.

Ultra-broadband near-field antenna for terahertz plasmonic applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Polischuk, O. V., E-mail: polischuk.sfire@mail.ru; Popov, V. V., E-mail: popov-slava@yahoo.co.uk; Knap, W.

A new type of ultra-broadband near-field antenna for terahertz frequencies is proposed. This antenna is a short-period planar metal array. It is theoretically shown that irradiation of the short-period array antenna by a plane homogeneous terahertz waves excite a highly inhomogeneous near electric field near the metal array. In this case, the amplitude of the excited inhomogeneous near electric field is almost independent of frequency in the entire terahertz frequency range. The excitation of plasma oscillations in a two-dimensional electron system using the antenna under study is numerically simulated in the resonant and non-resonant plasmonic response modes. This type ofmore » antenna can be used for developing ultra-broadband plasmonic detectors of terahertz radiation.« less

Advanced Mirror Technology Development (AMTD) Project: 3.0 Year Status

NASA Technical Reports Server (NTRS)

Stahl, H. Philip

2015-01-01

Advanced Mirror Technology Development (AMTD) is a funded NASA Strategic Astrophysics Technology project. Begun in 2011, we are in Phase 2 of a multi-year effort. Our objective is to mature towards TRL6 critical technologies needed to produce 4-m or larger flight-qualified UVOIR mirrors by 2018 so that a viable astronomy mission can be considered by the 2020 Decadal Review. The developed technology must enable missions capable of both general astrophysics and ultra-high contrast observations of exoplanets. Just as JWST's architecture was driven by launch vehicle, a future UVOIR mission's architecture (monolithic, segmented or interferometric) will depend on capacities of future launch vehicles (and budget). Since we cannot predict the future, we must prepare for all potential futures. Therefore, we are pursuing multiple technology paths. AMTD uses a science-driven systems engineering approach. We mature technologies required to enable the highest priority science AND result in a high-performance low-cost low-risk system. One of our key accomplishments is that we have derived engineering specifications for advanced normal-incidence monolithic and segmented mirror systems needed to enable both general astrophysics and ultra-high contrast observations of exoplanets missions as a function of potential launch vehicle and its inherent mass and volume constraints. Another key accomplishment is that we have matured our technology by building and testing hardware. To demonstrate stacked core technology, we built a 400 mm thick mirror. Currently, to demonstrate lateral scalability, we are manufacturing a 1.5 meter mirror. To assist in architecture trade studies, the Engineering team develops Structural, Thermal and Optical Performance (STOP) models of candidate mirror assembly systems including substrates, structures, and mechanisms. These models are validated by test of full- and subscale components in relevant thermo-vacuum environments. Specific analyses include: maximum mirror substrate size, first fundamental mode frequency (i.e., stiffness) and mass required to fabricate without quilting, survive launch, and achieve stable pointing and maximum thermal time constant.

Ultra-short pulse generator

DOEpatents

McEwan, T.E.

1993-12-28

An inexpensive pulse generating circuit is disclosed that generates ultra-short, 200 picosecond, and high voltage 100 kW, pulses suitable for wideband radar and other wideband applications. The circuit implements a nonlinear transmission line with series inductors and variable capacitors coupled to ground made from reverse biased diodes to sharpen and increase the amplitude of a high-voltage power MOSFET driver input pulse until it causes non-destructive transit time breakdown in a final avalanche shock wave diode, which increases and sharpens the pulse even more. 5 figures.

Ultra-short pulse generator

DOEpatents

McEwan, Thomas E.

1993-01-01

An inexpensive pulse generating circuit is disclosed that generates ultra-short, 200 picosecond, and high voltage 100 kW, pulses suitable for wideband radar and other wideband applications. The circuit implements a nonlinear transmission line with series inductors and variable capacitors coupled to ground made from reverse biased diodes to sharpen and increase the amplitude of a high-voltage power MOSFET driver input pulse until it causes non-destructive transit time breakdown in a final avalanche shockwave diode, which increases and sharpens the pulse even more.

Monolithic Integration of Two-Dimensional Liquid Chromatography-Capillary Electrophoresis and Electrospray Ionization on a Microfluidic Device

PubMed Central

Chambers, Andrew G.; Mellors, J. Scott; Henley, W. Hampton; Ramsey, J. Michael

2011-01-01

A microfluidic device capable of two-dimensional reversed-phase liquid chromatography-capillary electrophoresis with integrated electrospray ionization (LC-CE-ESI) for mass spectrometry (MS)-based proteomic applications is described. Traditional instrumentation was used for the LC sample injection and delivery of the LC mobile phase. The glass microfabricated device incorporated a sample-trapping region and an LC channel packed with reversed-phase particles. Rapid electrokinetic injections of the LC effluent into the CE dimension were performed at a cross channel intersection. The CE separation channel terminated at a corner of the square device, which functioned as an integrated electrospray tip. In addition to LC-CE-ESI, this device was used for LC-ESI without any instrumental modifications. To evaluate the system, LC-MS and LC-CE-MS analysis of protein digests were performed and compared. PMID:21214194

MMIC LNA based novel composite-channel Al0.3Ga0.7N/Al0.05Ga0.95N/GaNHEMTs

NASA Astrophysics Data System (ADS)

Cheng, Zhi-Qun; Cai, Yong; Liu, Jie; Zhou, Yu-Gang; Lau Kei, May; Chen, Kevin J.

2007-11-01

A microwave monolithic integrated circuit (MMIC) C-band low noise amplifier (LNA) using 1 μm-gate composite-channel Al0.3Ga0.7N/Al0.05Ga0.95N/GaN high electron mobility transistors (CC-HEMTs) has been designed, fabricated and characterized. The material structure and special channel of CC-HEMT were given and analysed. The MMIC LNA with CC-HEMT showed a noise figure of 2.4 dB, an associated gain of 12.3 dB, an input return loss of -6 dB and an output return loss of -16 dB at 6 GHz. The IIP3 of the LNA is 13 dBm at 6 GHz. The LNA with 1 μm × 100 μm device showed very high-dynamic range with decent gain and noise figure.

Nine-channel wavelength tunable single mode laser array based on slots.

PubMed

Guo, Wei-Hua; Lu, Qiaoyin; Nawrocka, Marta; Abdullaev, Azat; O'Callaghan, James; Donegan, John F

2013-04-22

A 9-channel wavelength tunable single-mode laser array based on slots is presented. The fabricated laser array demonstrated a threshold current in a range of 19~21 mA with the SOA unbiased at 20°C under continuous wave condition. Stable single mode performances have been observed with side-mode suppression-ratio (SMSR) > 50 dB. The output power higher than 37 mW was obtained at the SOA injected current of 70 mA for all the 9 channels within the laser array. A wavelength quasi-continuous tuning range of about 27 nm has been achieved for the laser array with the temperature variations from 10°C to 45°C. This array platform is of a single growth and monolithically integrable. It can be easily fabricated by standard photolithography. In addition, it potentially removes the yield problem due to the uncertainty of the facet cleaving.

Instruments at the Lowell Observatory Discovery Channel Telescope (DCT)

NASA Astrophysics Data System (ADS)

Jacoby, George H.; Bida, Thomas A.; Fischer, Debra; Horch, Elliott; Kutyrev, Alexander; Mace, Gregory N.; Massey, Philip; Roe, Henry G.; Prato, Lisa A.

2017-01-01

The Lowell Observatory Discovery Channel Telescope (DCT) has been in full science operation for 2 years (2015 and 2016). Five instruments have been commissioned during that period, and two additional instruments are planned for 2017. These include:+ Large Monolithic Imager (LMI) - a CCD imager (12.6 arcmin FoV)+ DeVeny - a general purpose optical spectrograph (2 arcmin slit length, 10 grating choices)+ NIHTS - a low resolution (R=160) YJHK spectrograph (1.3 arcmin slit)+ DSSI - a two-channel optical speckle imager (5 arcsec FoV)+ IGRINS - a high resolution (45,000) HK spectrograph, on loan from the University of Texas.In the upcoming year, instruments will be delivered from the University of Maryland (RIMAS - a YJHK imager/spectrograph) and from Yale University (EXPRES - a very high resolution stabilized optical echelle for PRV).Each of these instruments will be described, along with their primary science goals.

Description and properties of a resistive network applied to emission tomography detector readouts

NASA Astrophysics Data System (ADS)

Boisson, F.; Bekaert, V.; Sahr, J.; Brasse, D.

2017-11-01

Over the last twenty years, PET systems have used discrete crystal detector modules coupled to multi-channel photodetectors, mostly to improve the spatial resolution. Although reading each readout channels individually would be of great interest, costs associated with the electronics would, in most cases, be too expensive. It is therefore essential to propose lower-cost solutions that do not degrade the overall system's performance. One possible solution to reduce the development costs of a PET system without degrading performance is the use of a resistive network which reduces the total number of readout channels. In this study, we present a symmetric charge division resistive network and associated software methods to assess the performance of a PET detector. Our approach consists in keeping the n lines and n columns information provided by a symmetric charge division circuit (SCD). We provided equations relative to output currents of the network, which enable estimation of the charge. We propose a novel approach to reconstruct the charge distribution from the lines and columns projection using a maximum likelihood expectation maximization (MLEM) approach which takes the non-uniformity of the photodetector channel gains into account. We also introduce a mathematical proof of the relation between the sigma of the reconstructed charge distribution and the Ratio between the line of interest (maximum value) and the background signal charges. To the best of our knowledge, this is the first study reporting these equations. Preliminary results obtained with a resistive network used in readout of a monolithic 50 × 50 × 8mm3 LYSO crystal coupled to a H9500 PMT validated the effectiveness of the reconstructed charge distribution to optimize both the x and y spatial resolution and the energy resolution. We obtained a mean x and y spatial resolution of 1.10 mm FWHM and a 14.7% energy resolution by calculating the integral of the reconstructed charge distribution. Finally, the relation between the ratio and the sigma of the reconstructed charge distribution may provide new opportunities in terms of Depth-of-Interaction estimation when using a monolithic crystal coupled to a multi-channel photodetector.

NSLS-II HIGH LEVEL APPLICATION INFRASTRUCTURE AND CLIENT API DESIGN

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shen, G.; Yang; L.

2011-03-28

The beam commissioning software framework of NSLS-II project adopts a client/server based architecture to replace the more traditional monolithic high level application approach. It is an open structure platform, and we try to provide a narrow API set for client application. With this narrow API, existing applications developed in different language under different architecture could be ported to our platform with small modification. This paper describes system infrastructure design, client API and system integration, and latest progress. As a new 3rd generation synchrotron light source with ultra low emittance, there are new requirements and challenges to control and manipulate themore » beam. A use case study and a theoretical analysis have been performed to clarify requirements and challenges to the high level applications (HLA) software environment. To satisfy those requirements and challenges, adequate system architecture of the software framework is critical for beam commissioning, study and operation. The existing traditional approaches are self-consistent, and monolithic. Some of them have adopted a concept of middle layer to separate low level hardware processing from numerical algorithm computing, physics modelling, data manipulating, plotting, and error handling. However, none of the existing approaches can satisfy the requirement. A new design has been proposed by introducing service oriented architecture technology. The HLA is combination of tools for accelerator physicists and operators, which is same as traditional approach. In NSLS-II, they include monitoring applications and control routines. Scripting environment is very important for the later part of HLA and both parts are designed based on a common set of APIs. Physicists and operators are users of these APIs, while control system engineers and a few accelerator physicists are the developers of these APIs. With our Client/Server mode based approach, we leave how to retrieve information to the developers of APIs and how to use them to form a physics application to the users. For example, how the channels are related to magnet and what the current real-time setting of a magnet is in physics unit are the internals of APIs. Measuring chromaticities are the users of APIs. All the users of APIs are working with magnet and instrument names in a physics unit. The low level communications in current or voltage unit are minimized. In this paper, we discussed our recent progress of our infrastructure development, and client API.« less

A 64-channel ultra-low power system-on-chip for local field and action potentials recording

NASA Astrophysics Data System (ADS)

Rodríguez-Pérez, Alberto; Delgado-Restituto, Manuel; Darie, Angela; Soto-Sánchez, Cristina; Fernández-Jover, Eduardo; Rodríguez-Vázquez, Ángel

2015-06-01

This paper reports an integrated 64-channel neural recording sensor. Neural signals are acquired, filtered, digitized and compressed in the channels. Additionally, each channel implements an auto-calibration mechanism which configures the transfer characteristics of the recording site. The system has two transmission modes; in one case the information captured by the channels is sent as uncompressed raw data; in the other, feature vectors extracted from the detected neural spikes are released. Data streams coming from the channels are serialized by an embedded digital processor. Experimental results, including in vivo measurements, show that the power consumption of the complete system is lower than 330μW.

Short-focus and ultra-wide-angle lens design in wavefront coding

NASA Astrophysics Data System (ADS)

Zhang, Jiyan; Huang, Yuanqing; Xiong, Feibing

2016-10-01

Wavefront coding (WFC) is a hybrid technology designed to increase depth of field of conventional optics. The goal of our research is to apply this technology to the short-focus and ultra-wide-angle lens which suffers from the aberration related with large field of view (FOV) such as coma and astigmatism. WFC can also be used to compensate for other aberration which is sensitive to the FOV. Ultra-wide-angle lens has a little depth of focus because it has small F number and short-focus. We design a hybrid lens combing WFC with the ultra-wide-angle lens. The full FOV and relative aperture of the final design are up to170° and 1/1.8 respectively. The focal length is 2 mm. We adopt the cubic phase mask (CPM) in the design. The conventional design will have a wide variation of the point spread function (PSF) across the FOV and it is very sensitive with the variation of the FOV. The new design we obtain the PSF is nearly invariant over the whole FOV. But the result of the design also shows the little difference between the horizontal and vertical length of the PSF. We analyze that the CPM is non-symmetric phase mask and the FOV is so large, which will generate variation in the final image quality. For that reason, we apply a new method to avoid that happened. We try to make the rays incident on the CPM with small angle and decrease the deformation of the PSF. The experimental result shows the new method to optimize the CPM is fit for the ultra-wide-angle lens. The research above will be a helpful instruction to design the ultra-wide-angle lens with WFC.

Monolithic liquid crystal waveguide Fourier transform spectrometer for gas species sensing

NASA Astrophysics Data System (ADS)

Chao, Tien-Hsin; Lu, Thomas T.; Davis, Scott R.; Rommel, Scott D.; Farca, George; Luey, Ben; Martin, Alan; Anderson, Michael H.

2011-04-01

Jet Propulsion Lab and Vescent Photonics Inc. and are jointly developing an innovative ultracompact (volume < 10 cm3), ultra-low power (<10-3 Watt-hours per measurement and zero power consumption when not measuring), completely non-mechanical Liquid Crystal Waveguide Fourier Transform Spectrometer (LCWFTS) that will be suitable for a variety of remote-platform, in-situ measurements. These devices are made possible by novel electro-evanescent waveguide architecture, enabling "monolithic chip-scale" Electro Optic-FTS (EO-FTS) sensors. The potential performance of these EO-FTS sensors include: i) a spectral range throughout 0.4-5 μm (25000 - 2000 cm-1), ii) high-resolution (Δλ <= 0.1 nm), iii) high-speed (< 1 ms) measurements, and iv) rugged integrated optical construction. This performance potential enables the detection and quantification of a large number of different atmospheric gases simultaneously in the same air mass and the rugged construction will enable deployment on previously inaccessible platforms. The sensor construction is also amenable for analyzing aqueous samples on remote floating or submerged platforms. We will report a proof-of-principle prototype LCWFTS sensor that has been demonstrated in the near-IR (range of 1450-1700 nm) with a 5 nm resolution. This performance is in good agreement with theoretical models, which are being used to design and build the next generation LCWFTS devices.

Ultra-fast high-resolution hybrid and monolithic CMOS imagers in multi-frame radiography

NASA Astrophysics Data System (ADS)

Kwiatkowski, Kris; Douence, Vincent; Bai, Yibin; Nedrow, Paul; Mariam, Fesseha; Merrill, Frank; Morris, Christopher L.; Saunders, Andy

2014-09-01

A new burst-mode, 10-frame, hybrid Si-sensor/CMOS-ROIC FPA chip has been recently fabricated at Teledyne Imaging Sensors. The intended primary use of the sensor is in the multi-frame 800 MeV proton radiography at LANL. The basic part of the hybrid is a large (48×49 mm2) stitched CMOS chip of 1100×1100 pixel count, with a minimum shutter speed of 50 ns. The performance parameters of this chip are compared to the first generation 3-frame 0.5-Mpixel custom hybrid imager. The 3-frame cameras have been in continuous use for many years, in a variety of static and dynamic experiments at LANSCE. The cameras can operate with a per-frame adjustable integration time of ~ 120ns-to- 1s, and inter-frame time of 250ns to 2s. Given the 80 ms total readout time, the original and the new imagers can be externally synchronized to 0.1-to-5 Hz, 50-ns wide proton beam pulses, and record up to ~1000-frame radiographic movies typ. of 3-to-30 minute duration. The performance of the global electronic shutter is discussed and compared to that of a high-resolution commercial front-illuminated monolithic CMOS imager.

Quantum preservation of the measurements precision using ultra-short strong pulses in exact analytical solution

NASA Astrophysics Data System (ADS)

Berrada, K.; Eleuch, H.

2017-09-01

Various schemes have been proposed to improve the parameter-estimation precision. In the present work, we suggest an alternative method to preserve the estimation precision by considering a model that closely describes a realistic experimental scenario. We explore this active way to control and enhance the measurements precision for a two-level quantum system interacting with classical electromagnetic field using ultra-short strong pulses with an exact analytical solution, i.e. beyond the rotating wave approximation. In particular, we investigate the variation of the precision with a few cycles pulse and a smooth phase jump over a finite time interval. We show that by acting on the shape of the phase transient and other parameters of the considered system, the amount of information may be increased and has smaller decay rate in the long time. These features make two-level systems incorporated in ultra-short, of-resonant and gradually changing phase good candidates for implementation of schemes for the quantum computation and the coherent information processing.

Propagation and spatiotemporal coupling characteristics of ultra-short Gaussian vortex pulse

NASA Astrophysics Data System (ADS)

Nie, Jianye; Liu, Guodong; Zhang, Rongzhu

2018-05-01

Based on Collins diffraction integral formula, the propagation equation of ultra-short Gaussian vortex pulse beam has been derived. Using the equation, the intensity distribution variations of vortex pulse in the propagation process are calculated. Specially, the spatiotemporal coupling characteristics of ultra-short vortex beams are discussed in detail. The results show that some key parameters, such as transverse distance, transmission distance, pulse width and topological charge number will influence the spatiotemporal coupling characteristics significantly. With the increasing of transverse distance, the waveforms of the pulses distort obviously. And when transmission distance is far than 50 mm, the distribution curve of transverse intensity gradually changes into a Gaussian type. In addition, initial pulse width will affect the distribution of light field, however, when initial pulse width is larger than 3 fs, the spatiotemporal coupling effect will be insignificant. Topological charge number does not affect the time delay characteristics, since with the increasing of topological charge number, the waveform of the pulse distorts gradually but the time delay does not occur.

In-orbit Calibrations of the Ultraviolet Imaging Telescope

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tandon, S. N.; Subramaniam, Annapurni; Sankarasubramanian, K.

The Ultra-Violet Imaging Telescope (UVIT) is one of the payloads in ASTROSAT, the first Indian Space Observatory. The UVIT instrument has two 375 mm telescopes: one for the far-ultraviolet (FUV) channel (1300–1800 Å), and the other for the near-ultraviolet (NUV) channel (2000–3000 Å) and the visible (VIS) channel (3200–5500 Å). UVIT is primarily designed for simultaneous imaging in the two ultraviolet channels with spatial resolution better than 1.″8, along with provisions for slit-less spectroscopy in the NUV and FUV channels. The results of in-orbit calibrations of UVIT are presented in this paper.

Ultra-wideband ladder filter using SH(0) plate wave in thin LiNbO(3) plate and its application to tunable filter.

PubMed

Kadota, Michio; Tanaka, Shuji

2015-05-01

A cognitive radio terminal using vacant frequency bands of digital TV (DTV) channels, i.e., TV white space, strongly requires a compact tunable filter covering a wide frequency range of the DTV band (470 to 710 MHz in Japan). In this study, a T-type ladder filter using ultra-wideband shear horizontal mode plate wave resonators was fabricated, and a low peak insertion loss of 0.8 dB and an ultra-large 6 dB bandwidth of 240 MHz (41%) were measured in the DTV band. In addition, bandpass filters with different center frequencies of 502 and 653 MHz at 6 dB attenuation were numerically synthesized based on the same T-type ladder filter in conjunction with band rejection filters with different frequencies. The results suggest that the combination of the wideband T-type ladder filter and the band rejection filters connected with variable capacitors enables a tunable filter with large tunability of frequency and bandwidth as well as large rejection at the adjacent channels of an available TV white space.

Ultra-low profile Ovation device: is it the definitive solution for EVAR?

PubMed

de Donato, G; Setacci, F; Sirignano, P; Galzerano, G; Borrelli, M P; di Marzo, L; Setacci, C

2014-02-01

When Juan Parodi implanted an endograft in a human body for the first time on September 7, 1990 in Buenos Aires, Argentina, the delivery system of the handmade device was primitive, extremely rigid, and had a bulky profile of 27 French (F). Since then, stent-graft technology has evolved rapidly, limitations of earlier-generation devices have been overtaken, and endovascular aneurysm repair (EVAR) eligibility has increased enormously. Nevertheless (still) challenging aortoiliac anatomy such as short and complex proximal aortic neck seal zones and narrow access vessels are responsible for EVAR ineligibility in up to 50% of cases. The Ovation Prime abdominal stent-graft system (TriVascular, Inc., Santa Rosa, CA, USA) is a trimodular device designed with the aortic body delivered via a flexible, hydrophilic-coated, ultra-low profile catheter (14-F outer diameter - OD). The aortic body is provided with a suprarenal nitinol stent with anchors that provide active fixation, while a network of rings and channels that are inflated with a low-viscosity radiopaque polymer during stent-graft deployment, provides effective sealing. The previous EVAR technology aimed to both anchor and seal using stents combined with fabric, with neither optimized for their roles and each forced to compete for the same space within their delivery catheters, which inevitably led to larger profile of the delivery system. The technical revolution of the Ovation endograft includes the idea to truly uncouple the stages of stent-graft fixation and seal during the procedure. In the Ovation endograft platform, stent and fabric are not competing the same space within the delivery system and an ultra-low profile delivery can be achieved without compromise. With such a low-profile delivery catheter, approximately 90% of men and 70% of women with abdominal aortic aneurysm have access vessel diameters considered fit for endovascular repair. The aim of this review paper was to analyze the main properties of Ovation endograft, to emphasize the advantage of the ultra-low profile device, and to sum up current literature.

Intraday and Interday Reliability of Ultra-Short-Term Heart Rate Variability in Rugby Union Players.

PubMed

Nakamura, Fábio Y; Pereira, Lucas A; Esco, Michael R; Flatt, Andrew A; Moraes, José E; Cal Abad, Cesar C; Loturco, Irineu

2017-02-01

Nakamura, FY, Pereira, LA, Esco, MR, Flatt, AA, Moraes, JE, Cal Abad, CC, and Loturco, I. Intraday and interday reliability of ultra-short-term heart rate variability in rugby union players. J Strength Cond Res 31(2): 548-551, 2017-The aim of this study was to examine the intraday and interday reliability of ultra-short-term vagal-related heart rate variability (HRV) in elite rugby union players. Forty players from the Brazilian National Rugby Team volunteered to participate in this study. The natural log of the root mean square of successive RR interval differences (lnRMSSD) assessments were performed on 4 different days. The HRV was assessed twice (intraday reliability) on the first day and once per day on the following 3 days (interday reliability). The RR interval recordings were obtained from 2-minute recordings using a portable heart rate monitor. The relative reliability of intraday and interday lnRMSSD measures was analyzed using the intraclass correlation coefficient (ICC). The typical error of measurement (absolute reliability) of intraday and interday lnRMSSD assessments was analyzed using the coefficient of variation (CV). Both intraday (ICC = 0.96; CV = 3.99%) and interday (ICC = 0.90; CV = 7.65%) measures were highly reliable. The ultra-short-term lnRMSSD is a consistent measure for evaluating elite rugby union players, in both intraday and interday settings. This study provides further validity to using this shortened method in practical field conditions with highly trained team sports athletes.

Ultra high speed optical transmission using subcarrier-multiplexed four-dimensional LDPC-coded modulation.

PubMed

Batshon, Hussam G; Djordjevic, Ivan; Schmidt, Ted

2010-09-13

We propose a subcarrier-multiplexed four-dimensional LDPC bit-interleaved coded modulation scheme that is capable of achieving beyond 480 Gb/s single-channel transmission rate over optical channels. Subcarrier-multiplexed four-dimensional LDPC coded modulation scheme outperforms the corresponding dual polarization schemes by up to 4.6 dB in OSNR at BER 10(-8).

Measurement and compensation schemes for the pulse front distortion of ultra-intensity ultra-short laser pulses

NASA Astrophysics Data System (ADS)

Wu, Fenxiang; Xu, Yi; Yu, Linpeng; Yang, Xiaojun; Li, Wenkai; Lu, Jun; Leng, Yuxin

2016-11-01

Pulse front distortion (PFD) is mainly induced by the chromatic aberration in femtosecond high-peak power laser systems, and it can temporally distort the pulse in the focus and therefore decrease the peak intensity. A novel measurement scheme is proposed to directly measure the PFD of ultra-intensity ultra-short laser pulses, which can work not only without any extra struggle for the desired reference pulse, but also largely reduce the size of the required optical elements in measurement. The measured PFD in an experimental 200TW/27fs laser system is in good agreement with the calculated result, which demonstrates the validity and feasibility of this method effectively. In addition, a simple compensation scheme based on the combination of concave lens and parabolic lens is also designed and proposed to correct the PFD. Based on the theoretical calculation, the PFD of above experimental laser system can almost be completely corrected by using this compensator with proper parameters.

Ultra-Low-Noise W-Band MMIC Detector Modules

NASA Technical Reports Server (NTRS)

Gaier, Todd C.; Samoska, Lorene A.; Kangaslahti, Pekka P.; Van Vinkle, Dan; Tantawi, Sami; Fox, John; Church, Sarah E.; Lau, Jusy M.; Sieth, Matthew M.; Voll, Patricia E.;

Dimensional stability. [of glass and glass-ceramic materials in diffraction telescopes

NASA Technical Reports Server (NTRS)

Hochen, R.; Justie, B.

1976-01-01

The temporal stability of glass and glass-ceramic materials is important to the success of a large diffraction-limited telescope. The results are presented of an experimental study of the dimensional stability of glasses and glass ceramics being considered for substrates of massive diffraction-limited mirrors designed for several years of service in earth orbit. The purpose of the study was to measure the relative change in length of the candidate substrate materials, to the order of 5 parts in 10 to the 8th power, as a function of several years time. The development of monolithic test etalons, the development and improvement of two types of ultra-high precision interferometers, and certain aspects of tests data presently achieved are discussed.

Femtosecond timing-jitter between photo-cathode laser and ultra-short electron bunches by means of hybrid compression

NASA Astrophysics Data System (ADS)

Pompili, R.; Anania, M. P.; Bellaveglia, M.; Biagioni, A.; Castorina, G.; Chiadroni, E.; Cianchi, A.; Croia, M.; Di Giovenale, D.; Ferrario, M.; Filippi, F.; Gallo, A.; Gatti, G.; Giorgianni, F.; Giribono, A.; Li, W.; Lupi, S.; Mostacci, A.; Petrarca, M.; Piersanti, L.; Di Pirro, G.; Romeo, S.; Scifo, J.; Shpakov, V.; Vaccarezza, C.; Villa, F.

2016-08-01

The generation of ultra-short electron bunches with ultra-low timing-jitter relative to the photo-cathode (PC) laser has been experimentally proved for the first time at the SPARC_LAB test-facility (INFN-LNF, Frascati) exploiting a two-stage hybrid compression scheme. The first stage employs RF-based compression (velocity-bunching), which shortens the bunch and imprints an energy chirp on it. The second stage is performed in a non-isochronous dogleg line, where the compression is completed resulting in a final bunch duration below 90 fs (rms). At the same time, the beam arrival timing-jitter with respect to the PC laser has been measured to be lower than 20 fs (rms). The reported results have been validated with numerical simulations.

Coffee-Ring Defined Short Channels for Inkjet-Printed Metal Oxide Thin-Film Transistors.

PubMed

Li, Yuzhi; Lan, Linfeng; Xiao, Peng; Sun, Sheng; Lin, Zhenguo; Song, Wei; Song, Erlong; Gao, Peixiong; Wu, Weijing; Peng, Junbiao

2016-08-03

Short-channel electronic devices several micrometers in length are difficult to implement by direct inkjet printing due to the limitation of position accuracy of the common inkjet printer system and the spread of functional ink on substrates. In this report, metal oxide thin-film transistors (TFTs) with channel lengths of 3.5 ± 0.7 μm were successfully fabricated with a common inkjet printer without any photolithography steps. Hydrophobic CYTOP coffee stripes, made by inkjet-printing and plasma-treating processes, were utilized to define the channel area of TFTs with channel lengths as short as ∼3.5 μm by dewetting the inks of the source/drain (S/D) precursors. Furthermore, by introduction of an ultrathin layer of PVA to modify the S/D surfaces, the spreading of precursor ink of the InOx semiconductor layer was well-controlled. The inkjet-printed short-channel TFTs exhibited a maximum mobility of 4.9 cm(2) V(-1) s(-1) and an on/off ratio of larger than 10(9). This approach of fabricating short-channel TFTs by inkjet printing will promote the large-area fabrication of short-channel TFTs in a cost-effective manner.

A monolithic and flexible fluoropolymer film microreactor for organic synthesis applications.

PubMed

Kim, Jin-Oh; Kim, Heejin; Ko, Dong-Hyeon; Min, Kyoung-Ik; Im, Do Jin; Park, Soo-Young; Kim, Dong-Pyo

2014-11-07

A photocurable and viscous fluoropolymer with chemical stability is a highly desirable material for fabrication of microchemical devices. Lack of a reliable fabrication method, however, limits actual applications for organic reactions. Herein, we report fabrication of a monolithic and flexible fluoropolymer film microreactor and its use as a new microfluidic platform. The fabrication involves facile soft lithography techniques that enable partial curing of thin laminates, which can be readily bonded by conformal contact without any external forces. We demonstrate fabrication of various functional channels (~300 μm thick) such as those embedded with either a herringbone micromixer pattern or a droplet generator. Organic reactions under strongly acidic and basic conditions can be carried out in this film microreactor even at elevated temperature with excellent reproducibility. In particular, the transparent film microreactor with good deformability could be wrapped around a light-emitting lamp for close contact with the light source for efficient photochemical reactions with visible light, which demonstrates easy integration with optical components for functional miniaturized systems.

A monolithic patch-clamping amplifier with capacitive feedback.

PubMed

Prakash, J; Paulos, J J; Jensen, D N

1989-03-01

Patch-clamping is an established method for directly measuring ionic transport through cellular membranes with sufficient resolution to observe open/close transitions of individual channel molecules. This paper describes an alternative technique for patch-clamping which uses a capacitor as the transimpedance element. This approach eliminates bandwidth and saturation limitations experienced with resistive patch-clamping amplifiers. A complete monolithic design featuring an on-chip operational amplifier, a capacitor array with gain-ranging from 30 pF down to 0.03 pF, and reset and gain ranging switches has been fabricated using 5 microns CMOS technology. It is shown that the voltage noise of the CMOS operational amplifier limits the overall noise performance, but that performance competitive with conventional instruments can be achieved over a 10 kHz bandwidth, at least for small input capacitances (less than or equal to 5 pF). Results are presented along with an analysis and comparison of noise performance using both resistive and capacitive elements.

Integration of InGaAs MOSFETs and GaAs/ AlGaAs lasers on Si Substrate for advanced opto-electronic integrated circuits (OEICs).

PubMed

Kumar, Annie; Lee, Shuh-Ying; Yadav, Sachin; Tan, Kian Hua; Loke, Wan Khai; Dong, Yuan; Lee, Kwang Hong; Wicaksono, Satrio; Liang, Gengchiau; Yoon, Soon-Fatt; Antoniadis, Dimitri; Yeo, Yee-Chia; Gong, Xiao

2017-12-11

Lasers monolithically integrated with high speed MOSFETs on the silicon (Si) substrate could be a key to realize low cost, low power, and high speed opto-electronic integrated circuits (OEICs). In this paper, we report the monolithic integration of InGaAs channel transistors with electrically pumped GaAs/AlGaAs lasers on the Si substrate for future advanced OEICs. The laser and transistor layers were grown on the Si substrate by molecular beam epitaxy (MBE) using direct epitaxial growth. InGaAs n-FETs with an I ON /I OFF ratio of more than 10 6 with very low off-state leakage and a low subthreshold swing with a minimum of 82 mV/decade were realized. Electrically pumped GaAs/AlGaAs quantum well (QW) lasers with a lasing wavelength of 795 nm at room temperature were demonstrated. The overall fabrication process has a low thermal budget of no more than 400 °C.

Continuous flow immobilized enzyme reactor-tandem mass spectrometry for screening of AChE inhibitors in complex mixtures.

PubMed

Forsberg, Erica M; Green, James R A; Brennan, John D

2011-07-01

A method is described for identifying bioactive compounds in complex mixtures based on the use of capillary-scale monolithic enzyme-reactor columns for rapid screening of enzyme activity. A two-channel nanoLC system was used to continuously infuse substrate coupled with automated injections of substrate/small molecule mixtures, optionally containing the chromogenic Ellman reagent, through sol-gel derived acetylcholinesterase (AChE) doped monolithic columns. This is the first report of AChE encapsulated in monolithic silica for use as an immobilized enzyme reactor (IMER), and the first use of such IMERs for mixture screening. AChE IMER columns were optimized to allow rapid functional screening of compound mixtures based on changes in the product absorbance or the ratio of mass spectrometric peaks for product and substrate ions in the eluent. The assay had robust performance and produced a Z' factor of 0.77 in the presence of 2% (v/v) DMSO. A series of 52 mixtures consisting of 1040 compounds from the Canadian Compound Collection of bioactives was screened and two known inhibitors, physostigmine and 9-aminoacridine, were identified from active mixtures by manual deconvolution. The activity of the compounds was confirmed using the enzyme reactor format, which allowed determination of both IC(50) and K(I) values. Screening results were found to correlate well with a recently published fluorescence-based microarray screening assay for AChE inhibitors.

Monolithic integrated optic fiber Bragg grating sensor interrogator

NASA Astrophysics Data System (ADS)

Mendoza, Edgar A.; Esterkin, Yan; Kempen, Cornelia; Sun, Songjian

2010-04-01

Fiber Bragg gratings (FBGs) are a mature sensing technology that has gained rapid acceptance in civil, aerospace, chemical and petrochemical, medicine, aviation and automotive industries. Fiber Bragg grating sensors can be use for a variety of measurements including strain, stress, vibration, acoustics, acceleration, pressure, temperature, moisture, and corrosion distributed at multiple locations within the structure using a single fiber element. The most prominent advantages of FBGs are: small size and light weight, multiple FBG transducers on a single fiber, and immunity to radio frequency interference. A major disadvantage of FBG technology is that conventional state-of-the-art fiber Bragg grating interrogation systems are typically bulky, heavy, and costly bench top instruments that are assembled from off-the-shelf fiber optic and optical components integrated with a signal electronics board into an instrument console. Based on the need for a compact FBG interrogation system, this paper describes recent progress towards the development of a miniature fiber Bragg grating sensor interrogator (FBG-TransceiverTM) system based on multi-channel monolithic integrated optic sensor microchip technology. The integrated optic microchip technology enables the monolithic integration of all of the functionalities, both passive and active, of conventional bench top FBG sensor interrogators systems, packaged in a miniaturized, low power operation, 2-cm x 5-cm small form factor (SFF) package suitable for the long-term structural health monitoring in applications where size, weight, and power are critical for operation.

Development of the Monolith Froth Reactor for Catalytic Wet Oxidation of CELSS Model Wastes

NASA Technical Reports Server (NTRS)

Fisher, John W.; Abraham, Martin

1993-01-01

The aqueous phase oxidation of acetic acid, used as a model compound for the treatment of CELSS (Controlled Ecological Life Support System) waste, was carried out in the monolith froth reactor which utilizes two-phase flow in the monolith channels. The catalytic oxidation of acetic acid was carried out over a Pt/Al2O3 catalyst at temperatures and pressures below the critical point of water. The effect of externally controllable parameters (temperature, liquid flow rate, distributor plate orifice size, pitch, and catalyst distance from the distributor plate) on the rate of acetic acid oxidation was investigated. Results indicate reaction rate increased with increasing temperature and exhibited a maximum with respect to liquid flow rate. The apparent activation energy calculated from reaction rate data was 99.7 kJ/mol. This value is similar to values reported for the oxidation of acetic acid in other systems and is comparable to intrinsic values calculated for oxidation reactions. The kinetic data were modeled using simple power law kinetics. The effect of "froth" feed system characteristics was also investigated. Results indicate that the reaction rate exhibits a maximum with respect to distributor plate orifice size, pitch, and catalyst distance from the distributor plate. Fundamental results obtained were used to extrapolate where the complete removal of acetic acid would be obtained and for the design and operation of a full scale CELSS treatment system.

A novel wavelength multiplexer/demutiplexer based on side-port multimode interference coupler

NASA Astrophysics Data System (ADS)

Wei, Shile; Jian, Wu; Zhao, Lingjuan; Qiu, Jifang; Yin, Zuoshan; Hui, Rongqing

2014-05-01

Based on side-port multimode interference coupler, a novel design of 1.31/1.55-μm wavelength multiplexer/demutiplexer on SOI platform with conventional channel waveguides is proposed and analyzed by using wide-angle beam propagation method. With a 25.9μm long ultra-short MMI section, nearly an order of magnitude shorter than that of the previously reported 1.31/1.55-μm wavelength MMI splitters on SOI, simulation results exhibit contrasts of 28dB and 25dB at wavelength 1.31 and 1.55 μm, respectively, and the insertion losses are both below 0.55dB. Meanwhile, the analysis shows that the proposed structure has larger fabrication tolerances than restricted MMI based structures and the present design methodology also applies to split other wavelengths and in different material platforms, such as InP, GaAs and PLC guides, etc.

Ultra-low contact resistance in graphene devices at the Dirac point

NASA Astrophysics Data System (ADS)

Anzi, Luca; Mansouri, Aida; Pedrinazzi, Paolo; Guerriero, Erica; Fiocco, Marco; Pesquera, Amaia; Centeno, Alba; Zurutuza, Amaia; Behnam, Ashkan; Carrion, Enrique A.; Pop, Eric; Sordan, Roman

2018-04-01

Contact resistance is one of the main factors limiting performance of short-channel graphene field-effect transistors (GFETs), preventing their use in low-voltage applications. Here we investigated the contact resistance between graphene grown by chemical vapor deposition (CVD) and different metals, and found that etching holes in graphene below the contacts consistently reduced the contact resistance, down to 23 Ω \\cdot μ m with Au contacts. This low contact resistance was obtained at the Dirac point of graphene, in contrast to previous studies where the lowest contact resistance was obtained at the highest carrier density in graphene (here 200 Ω \\cdot μ m was obtained under such conditions). The ‘holey’ Au contacts were implemented in GFETs which exhibited an average transconductance of 940 S m-1 at a drain bias of only 0.8 V and gate length of 500 nm, which out-perform GFETs with conventional Au contacts.

Measuring the radio emission of cosmic ray air showers with LOPES

NASA Astrophysics Data System (ADS)

Schröder, F. G.; Apel, W. D.; Arteaga, J. C.; Asch, T.; Badea, F.; Bähren, L.; Bekk, K.; Bertaina, M.; Biermann, P. L.; Blümer, J.; Bozdog, H.; Brancus, I. M.; Brüggemann, M.; Buchholz, P.; Buitink, S.; Cantoni, E.; Chiavassa, A.; Cossavella, F.; Daumiller, K.; de Souza, V.; Di Pierro, F.; Doll, P.; Engel, R.; Falcke, H.; Finger, M.; Fuhrmann, D.; Gemmeke, H.; Ghia, P. L.; Glasstetter, R.; Grupen, C.; Haungs, A.; Heck, D.; Hörandel, J. R.; Horneffer, A.; Huege, T.; Isar, P. G.; Kampert, K.-H.; Kang, D.; Kickelbick, D.; Krömer, O.; Kuijpers, J.; Lafebre, S.; łuczak, P.; Ludwig, M.; Mathes, H. J.; Mayer, H. J.; Melissas, M.; Mitrica, B.; Morello, C.; Navarra, G.; Nehls, S.; Nigl, A.; Oehlschläger, J.; Over, S.; Palmieri, N.; Petcu, M.; Pierog, T.; Rautenberg, J.; Rebel, H.; Roth, M.; Saftoiu, A.; Schieler, H.; Schmidt, A.; Sima, O.; Singh, K.; Toma, G.; Trinchero, G. C.; Ulrich, H.; Weindl, A.; Wochele, J.; Wommer, M.; Zabierowski, J.; Zensus, J. A.

2010-05-01

When ultra high energy cosmic rays hit the atmosphere, they produce a shower of millions of secondary particles. Thereby the charged particles in the shower emit a radio pulse whilst deflected in the Earth's magnetic field. LOPES is a digital antenna array measuring these radio pulses in the frequency range from 40 to 80 MHz. It is located at the site of and triggered by the air shower experiment KASCADE-Grande at Karlsruhe Institute of Technology (KIT), Germany. In its present configuration, it consists of 15 east-west-polarized and 15 north-south-polarized, absolutely calibrated short dipole antennas, as well as 10 LPDAs (with two channels each). Furthermore, it serves as a test bench for technological developments, like new antenna types or a radio-based self-triggering ( LOPESSTAR). To achieve a good angular reconstruction and to digitally form a beam into the arrival direction of the shower, it has a precise time calibration.

Determination of ambroxol hydrochloride, methylparaben and benzoic acid in pharmaceutical preparations based on sequential injection technique coupled with monolithic column.

PubMed

Satínský, Dalibor; Huclová, Jitka; Ferreira, Raquel L C; Montenegro, Maria Conceição B S M; Solich, Petr

2006-02-13

The porous monolithic columns show high performance at relatively low pressure. The coupling of short monoliths with sequential injection technique (SIA) results in a new approach to implementation of separation step to non-separation low-pressure method. In this contribution, a new separation method for simultaneous determination of ambroxol, methylparaben and benzoic acid was developed based on a novel reversed-phase sequential injection chromatography (SIC) technique with UV detection. A Chromolith SpeedROD RP-18e, 50-4.6 mm column with 10 mm precolumn and a FIAlab 3000 system with a six-port selection valve and 5 ml syringe were used for sequential injection chromatographic separations in our study. The mobile phase used was acetonitrile-tetrahydrofuran-0.05M acetic acid (10:10:90, v/v/v), pH 3.75 adjusted with triethylamine, flow rate 0.48 mlmin(-1), UV-detection was at 245 nm. The analysis time was <11 min. A new SIC method was validated and compared with HPLC. The method was found to be useful for the routine analysis of the active compounds ambroxol and preservatives (methylparaben or benzoic acid) in various pharmaceutical syrups and drops.

Inhibitory effects of hesperetin on Kv1.5 potassium channels stably expressed in HEK 293 cells and ultra-rapid delayed rectifier K(+) current in human atrial myocytes.

PubMed

Wang, Huan; Wang, Hong-Fei; Wang, Chen; Chen, Yu-Fang; Ma, Rong; Xiang, Ji-Zhou; Du, Xin-Ling; Tang, Qiang

2016-10-15

In the present study, the inhibitory effects of hesperetin (HSP) on human cardiac Kv1.5 channels expressed in HEK 293 cells and the ultra-rapid delayed rectifier K(+) current (Ikur) in human atrial myocytes were examined by using the whole-cell configuration of the patch-clamp techniques. We found that hesperetin rapidly and reversibly suppressed human Kv1.5 current in a concentration dependent manner with a half-maximal inhibition (IC50) of 23.15 μΜ with a Hill coefficient of 0.89. The current was maximally diminished about 71.36% at a concentration of 300μM hesperetin. Hesperetin significantly positive shifted the steady-state activation curve of Kv1.5, while negative shifted the steady-state inactivation curve. Hesperetin also accelerated the inactivation and markedly slowed the recovery from the inactivation of Kv1.5 currents. Block of Kv1.5 currents by hesperetin was in a frequency dependent manner. However, inclusion of 30μM hesperetin in pipette solution produced no effect on Kv1.5 channel current, while the current were remarkable and reversibly inhibited by extracellular application of 30μM hesperetin. We also found that hesperetin potently and reversibly inhibited the ultra-repaid delayed K(+) current (Ikur) in human atrial myocytes, which is in consistent with the effects of hesperetin on Kv1.5 currents in HEK 293 cells. In conclusion, hesperetin is a potent inhibitor of Ikur (which is encoded by Kv1.5), with blockade probably due to blocking of both open state and inactivated state channels from outside of the cell. Copyright © 2016 Elsevier B.V. All rights reserved.

Two-dimensional angular energy spectrum of electrons accelerated by the ultra-short relativistic laser pulse

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borovskiy, A. V.; Galkin, A. L.; Department of Physics of MBF, Pirogov Russian National Research Medical University, 1 Ostrovitianov Street, Moscow 117997

The new method of calculating energy spectra of accelerated electrons, based on the parameterization by their initial coordinates, is proposed. The energy spectra of electrons accelerated by Gaussian ultra-short relativistic laser pulse at a selected angle to the axis of the optical system focusing the laser pulse in a low density gas are theoretically calculated. The two-peak structure of the electron energy spectrum is obtained. Discussed are the reasons for its appearance as well as an applicability of other models of the laser field.

Frontiers of beam diagnostics in plasma accelerators: Measuring the ultra-fast and ultra-cold

NASA Astrophysics Data System (ADS)

Cianchi, A.; Anania, M. P.; Bisesto, F.; Chiadroni, E.; Curcio, A.; Ferrario, M.; Giribono, A.; Marocchino, A.; Pompili, R.; Scifo, J.; Shpakov, V.; Vaccarezza, C.; Villa, F.; Mostacci, A.; Bacci, A.; Rossi, A. R.; Serafini, L.; Zigler, A.

2018-05-01

Advanced diagnostics are essential tools in the development of plasma-based accelerators. The accurate measurement of the quality of beams at the exit of the plasma channel is crucial to optimize the parameters of the plasma accelerator. 6D electron beam diagnostics will be reviewed with emphasis on emittance measurement, which is particularly complex due to large energy spread and divergence of the emerging beams, and on femtosecond bunch length measurements.

Acousto-Optic Tunable Filter for Time-Domain Processing of Ultra-Short Optical Pulses,

DTIC Science & Technology

The application of acousto - optic tunable filters for shaping of ultra-fast pulses in the time domain is analyzed and demonstrated. With the rapid...advance of acousto - optic tunable filter (AOTF) technology, the opportunity for sophisticated signal processing capabilities arises. AOTFs offer unique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, Hyun-Sik; Jeon, Sanghun, E-mail: jeonsh@korea.ac.kr

Upon light exposure, an indium-zinc-oxide (IZO) thin-film transistor (TFT) presents higher photoconductivity by several orders of magnitude at the negative gate bias region. Among various device geometrical factors, scaling down the channel length of the photo-transistor results in an anomalous increase in photoconductivity. To probe the origin of this high photoconductivity in short-channel device, we measured transient current, current–voltage, and capacitance–voltage characteristics of IZO–TFTs with various channel lengths and widths before and after illumination. Under the illumination, the equilibrium potential region which lies far from front interface exists only in short-channel devices, forming the un-depleted conducting back channel. This regionmore » plays an important role in carrier transport under the illumination, leading to high photoconductivity in short-channel devices. Photon exposure coupled with gate-modulated band bending for short-channel devices leads to the accumulation of V{sub o}{sup ++} at the front channel and screening negative gate bias, thereby generating high current flow in the un-depleted back-channel region.« less

A heterodyne interferometer for high-performance industrial metrology

NASA Astrophysics Data System (ADS)

Schuldt, Thilo; Gohlke, Martin; Weise, Dennis; Johann, Ulrich; Peters, Achim; Braxmaier, Claus

2008-11-01

We developed a compact, fiber-coupled heterodyne interferometer for translation and tilt metrology. Noise levels below 5 pm/√Hz in translation and below 10 nrad/√Hz in tilt measurement, both for frequencies above 10-2 Hz, were demonstrated in lab experiments. While this setup was developed with respect to the LISA (Laser Interferometer Space Antenna) space mission current activities focus on its adaptation for dimensional characterization of ultra-stable materials and industrial metrology. The interferometer is used in high-accuracy dilatometry measuring the coefficient of thermal expansion (CTE) of dimensionally highly stable materials such as carbon-fiber reinforced plastic (CFRP) and Zerodur. The facility offers the possibility to measure the CTE with an accuracy better 10-8/K. We also develop a very compact and quasi-monolithic sensor head utilizing ultra-low expansion glass material which is the basis for a future space-qualifiable interferometer setup and serves as a prototype for a sensor head used in industrial environment. For high resolution 3D profilometry and surface property measurements (i. e. roughness, evenness and roundness), a low-noise (<=1nm/√ Hz) actuator will be implemented which enables a scan of the measurement beam over the surface under investigation.

UHPLC-UV method for the determination of flavonoids in dietary supplements and for evaluation of their antioxidant activities.

PubMed

Magiera, Sylwia; Baranowska, Irena; Lautenszleger, Anna

2015-01-01

A simple and rapid ultra-high performance liquid chromatographic (UHPLC) method coupled with an ultraviolet detector (UV) has been developed and validated for the separation and determination of 14 major flavonoids ((±)-catechin, (-)-epicatechin, glycitin, (-)-epicatechin gallate, rutin, quercitrin, hesperidine, neohesperidine, daidzein, glycitein, quercetin, genistein, hesperetin, and biochanin A) in herbal dietary supplements. The flavonoids have been separated on a Chromolith Fast Gradient Monolithic RP-18e column utilizing a mobile phase composed of 0.05% trifluoroacetic acid in water and acetonitrile in gradient elution mode. Under these conditions, flavonoids were separated in a 5 min run. The selectivity of the developed UHPLC-UV method was confirmed by comparison with ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis. The validation parameters such as linearity, sensitivity, precision, and accuracy were found to be highly satisfactory. The optimized method was applied to determination of flavonoids in different dietary supplements. Additionally, the developed HPLC-UV method combined with 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) assay was used in the evaluation of antioxidant activity of the selected flavonoids. Copyright © 2014 Elsevier B.V. All rights reserved.

Medical applications of ultra-short pulse lasers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, B M; Marion, J E

1999-06-08

The medical applications for ultra short pulse lasers (USPLs) and their associated commercial potential are reviewed. Short pulse lasers offer the surgeon the possibility of precision cutting or disruption of tissue with virtually no thermal or mechanical damage to the surrounding areas. Therefore the USPL offers potential improvement to numerous existing medical procedures. Secondly, when USPLs are combined with advanced tissue diagnostics, there are possibilities for tissue-selective precision ablation that may allow for new surgeries that cannot at present be performed. Here we briefly review the advantages of short pulse lasers, examine the potential markets both from an investment communitymore » perspective, and from the view. of the technology provider. Finally nominal performance and cost requirements for the lasers, delivery systems and diagnostics and the present state of development will be addressed.« less

III-V Ultra-Thin-Body InGaAs/InAs MOSFETs for Low Standby Power Logic Applications

NASA Astrophysics Data System (ADS)

Huang, Cheng-Ying

As device scaling continues to sub-10-nm regime, III-V InGaAs/InAs metal- oxide-semiconductor ?eld-e?ect transistors (MOSFETs) are promising candidates for replacing Si-based MOSFETs for future very-large-scale integration (VLSI) logic applications. III-V InGaAs materials have low electron effective mass and high electron velocity, allowing higher on-state current at lower VDD and reducing the switching power consumption. However, III-V InGaAs materials have a narrower band gap and higher permittivity, leading to large band-to-band tunneling (BTBT) leakage or gate-induced drain leakage (GIDL) at the drain end of the channel, and large subthreshold leakage due to worse electrostatic integrity. To utilize III-V MOSFETs in future logic circuits, III-V MOSFETs must have high on-state performance over Si MOSFETs as well as very low leakage current and low standby power consumption. In this dissertation, we will report InGaAs/InAs ultra-thin-body MOSFETs. Three techniques for reducing the leakage currents in InGaAs/InAs MOSFETs are reported as described below. 1) Wide band-gap barriers: We developed AlAs0.44Sb0.56 barriers lattice-match to InP by molecular beam epitaxy (MBE), and studied the electron transport in In0.53Ga0.47As/AlAs 0.44Sb0.56 heterostructures. The InGaAs channel MOSFETs using AlAs0.44Sb0.56 bottom barriers or p-doped In0.52 Al0.48As barriers were demonstrated, showing significant suppression on the back barrier leakage. 2) Ultra-thin channels: We investigated the electron transport in InGaAs and InAs ultra-thin quantum wells and ultra-thin body MOSFETs (t ch ~ 2-4 nm). For high performance logic, InAs channels enable higher on-state current, while for low power logic, InGaAs channels allow lower BTBT leakage current. 3) Source/Drain engineering: We developed raised InGaAs and recessed InP source/drain spacers. The raised InGaAs source/drain spacers improve electrostatics, reducing subthreshold leakage, and smooth the electric field near drain, reducing BTBT leakage. With further replacement of raised InGaAs spacers by recessed, doping-graded InP spacers at high field regions, BTBT leakage can be reduced ~100:1. Using the above-mentioned techniques, record high performance InAs MOSFETs with a 2.7 nm InAs channel and a ZrO2 gate dielectric were demonstrated with Ion = 500 microA/microm at Ioff = 100 nA/microm and VDS =0.5 V, showing the highest on-state performance among all the III-V MOSFETs and comparable performance to 22 nm Si FinFETs. Record low leakage InGaAs MOSFETs with recessed InP source/drain spacers were also demonstrated with minimum I off = 60 pA/microm at 30 nm-Lg , and Ion = 150 microA/microm at I off = 1 nA/microm and VDS =0.5 V. This recessed InP source/drain spacer technique improves device scalability and enables III-V MOSFETs for low standby power logic applications. Furthermore, ultra-thin InAs channel MOSFETs were fabricated on Si substrates, exhibiting high yield and high transconductance gm ~2.0 mS/microm at 20 nm- Lg and VDS =0.5 V. With further scaling of gate lengths, a 12 nm-Lg III-V MOSFET has shown maximum Ion/Ioff ratio ~8.3x105 , confirming that III-V MOSFETs are scalable to sub-10-nm technology nodes.

Visible quality aluminum and nickel superpolish polishing technology enabling new missions

NASA Astrophysics Data System (ADS)

Carrigan, Keith G.

2011-06-01

It is now well understood that with US Department of Defense (DoD) budgets shrinking and the Services and Agencies demanding new systems which can be fielded more quickly, cost and schedule are being emphasized more and more. At the same time, the US has ever growing needs for advanced capabilities to support evolving Intelligence, Surveillance and Reconnaissance objectives. In response to this market demand for ever more cost-effective, faster to market, single-channel, athermal optical systems, we have developed new metal polishing technologies which allow for short-lead, low-cost metal substrates to replace more costly, longer-lead material options. In parallel, the commercial marketplace is being driven continually to release better, faster and cheaper electronics. Growth according to Moore's law, enabled by advancements in photolithography, has produced denser memory, higher resolution displays and faster processors. While the quality of these products continues to increase, their price is falling. This seeming paradox is driven by industry advancements in manufacturing technology. The next steps on this curve can be realized via polishing technology which allows low-cost metal substrates to replace costly Silicon based optics for use in ultra-short wavelength systems.

Physics of giant electromagnetic pulse generation in short-pulse laser experiments.

PubMed

Poyé, A; Hulin, S; Bailly-Grandvaux, M; Dubois, J-L; Ribolzi, J; Raffestin, D; Bardon, M; Lubrano-Lavaderci, F; D'Humières, E; Santos, J J; Nicolaï, Ph; Tikhonchuk, V

2015-04-01

In this paper we describe the physical processes that lead to the generation of giant electromagnetic pulses (GEMPs) at powerful laser facilities. Our study is based on experimental measurements of both the charging of a solid target irradiated by an ultra-short, ultra-intense laser and the detection of the electromagnetic emission in the GHz domain. An unambiguous correlation between the neutralization current in the target holder and the electromagnetic emission shows that the source of the GEMP is the remaining positive charge inside the target after the escape of fast electrons accelerated by the ultra-intense laser. A simple model for calculating this charge in the thick target case is presented. From this model and knowing the geometry of the target holder, it becomes possible to estimate the intensity and the dominant frequencies of the GEMP at any facility.

Ultra-short pulse delivery at high average power with low-loss hollow core fibers coupled to TRUMPF's TruMicro laser platforms for industrial applications

NASA Astrophysics Data System (ADS)

Baumbach, S.; Pricking, S.; Overbuschmann, J.; Nutsch, S.; Kleinbauer, J.; Gebs, R.; Tan, C.; Scelle, R.; Kahmann, M.; Budnicki, A.; Sutter, D. H.; Killi, A.

2017-02-01

Multi-megawatt ultrafast laser systems at micrometer wavelength are commonly used for material processing applications, including ablation, cutting and drilling of various materials or cleaving of display glass with excellent quality. There is a need for flexible and efficient beam guidance, avoiding free space propagation of light between the laser head and the processing unit. Solid core step index fibers are only feasible for delivering laser pulses with peak powers in the kW-regime due to the optical damage threshold in bulk silica. In contrast, hollow core fibers are capable of guiding ultra-short laser pulses with orders of magnitude higher peak powers. This is possible since a micro-structured cladding confines the light within the hollow core and therefore minimizes the spatial overlap between silica and the electro-magnetic field. We report on recent results of single-mode ultra-short pulse delivery over several meters in a lowloss hollow core fiber packaged with industrial connectors. TRUMPF's ultrafast TruMicro laser platforms equipped with advanced temperature control and precisely engineered opto-mechanical components provide excellent position and pointing stability. They are thus perfectly suited for passive coupling of ultra-short laser pulses into hollow core fibers. Neither active beam launching components nor beam trackers are necessary for a reliable beam delivery in a space and cost saving packaging. Long term tests with weeks of stable operation, excellent beam quality and an overall transmission efficiency of above 85 percent even at high average power confirm the reliability for industrial applications.

Bayesian sparse channel estimation

NASA Astrophysics Data System (ADS)

Chen, Chulong; Zoltowski, Michael D.

2012-05-01

In Orthogonal Frequency Division Multiplexing (OFDM) systems, the technique used to estimate and track the time-varying multipath channel is critical to ensure reliable, high data rate communications. It is recognized that wireless channels often exhibit a sparse structure, especially for wideband and ultra-wideband systems. In order to exploit this sparse structure to reduce the number of pilot tones and increase the channel estimation quality, the application of compressed sensing to channel estimation is proposed. In this article, to make the compressed channel estimation more feasible for practical applications, it is investigated from a perspective of Bayesian learning. Under the Bayesian learning framework, the large-scale compressed sensing problem, as well as large time delay for the estimation of the doubly selective channel over multiple consecutive OFDM symbols, can be avoided. Simulation studies show a significant improvement in channel estimation MSE and less computing time compared to the conventional compressed channel estimation techniques.

Fuel injection nozzle and method of manufacturing the same

DOE Office of Scientific and Technical Information (OSTI.GOV)

Monaghan, James Christopher; Johnson, Thomas Edward; Ostebee, Heath Michael

A fuel injection head for use in a fuel injection nozzle comprises a monolithic body portion comprising an upstream face, an opposite downstream face, and a peripheral wall extending therebetween. A plurality of pre-mix tubes are integrally formed with and extend axially through the body portion. Each of the pre-mix tubes comprises an inlet adjacent the upstream face, an outlet adjacent the downstream face, and a channel extending between the inlet and the outlet. Each pre-mix tube also includes at least one fuel injector that at least partially extends outward from an exterior surface of the pre-mix tube, wherein themore » fuel injector is integrally formed with the pre-mix tube and is configured to facilitate fuel flow between the body portion and the channel.« less

Integrated front-end electronics in a detector compatible process: source-follower and charge-sensitive preamplifier configurations

NASA Astrophysics Data System (ADS)

Ratti, Lodovico; Manghisoni, Massimo; Re, Valerio; Speziali, Valeria

2001-12-01

This study is concerned with the simulation and design of low-noise front-end electronics monolithically integrated on the same high-resistivity substrate as multielectrode silicon detectors, in a process made available by the Istituto per la Ricerca Scientifica e Tecnologica (ITC-IRST) of Trento, Italy. The integrated front-end solutions described in this paper use N-channel JFETs as basic elements. The first one is based upon an all-NJFET charge preamplifier designed to match detector capacitances of a few picofarads and available in both a resistive and a non resistive feedback configuration. In the second solution, a single NJFET in the source-follower configuration is connected to the detector, while its source is wired to an external readout channel through an integrated capacitor.

Fully Printed Stretchable Thin-Film Transistors and Integrated Logic Circuits.

PubMed

Cai, Le; Zhang, Suoming; Miao, Jinshui; Yu, Zhibin; Wang, Chuan

2016-12-27

This paper reports intrinsically stretchable thin-film transistors (TFTs) and integrated logic circuits directly printed on elastomeric polydimethylsiloxane (PDMS) substrates. The printed devices utilize carbon nanotubes and a type of hybrid gate dielectric comprising PDMS and barium titanate (BaTiO 3 ) nanoparticles. The BaTiO 3 /PDMS composite simultaneously provides high dielectric constant, superior stretchability, low leakage, as well as good printability and compatibility with the elastomeric substrate. Both TFTs and logic circuits can be stretched beyond 50% strain along either channel length or channel width directions for thousands of cycles while showing no significant degradation in electrical performance. This work may offer an entry into more sophisticated stretchable electronic systems with monolithically integrated sensors, actuators, and displays, fabricated by scalable and low-cost methods for real life applications.

Active mode-locking of mid-infrared quantum cascade lasers with short gain recovery time.

PubMed

Wang, Yongrui; Belyanin, Alexey

2015-02-23

We investigate the dynamics of actively modulated mid-infrared quantum cascade lasers (QCLs) using space- and time-domain simulations of coupled density matrix and Maxwell equations with resonant tunneling current taken into account. We show that it is possible to achieve active mode locking and stable generation of picosecond pulses in high performance QCLs with a vertical laser transition and a short gain recovery time by bias modulation of a short section of a monolithic Fabry-Perot cavity. In fact, active mode locking in QCLs with a short gain recovery time turns out to be more robust to the variation of parameters as compared to previously studied lasers with a long gain recovery time. We investigate the effects of spatial hole burning and phase locking on the laser output.

Ultra-Flexible, Invisible Thin-Film Transistors Enabled by Amorphous Metal Oxide/Polymer Channel Layer Blends

DTIC Science & Technology

2015-02-25

all the In 2 O 3 : x %PVP blends, where the polymer chains disrupt oxide lattice forma - tion at the nanoscale grain level rather than at the atomic...oxidative stability. [ 51,52 ] This result can be qualitatively ascribed to the endothermic M–O–M lattice forma - tion acting as heat absorber and the ultra... Irie , M. Komiyama , H. Yui , Supramol. Sci. 1998 , 5 , 411 . [40] D. B. Buchholz , J. Liu , T. J. Marks , M. Zhang , R. P. Chang

High resolution phoswich gamma-ray imager utilizing monolithic MPPC arrays with submillimeter pixelized crystals

NASA Astrophysics Data System (ADS)

Kato, T.; Kataoka, J.; Nakamori, T.; Kishimoto, A.; Yamamoto, S.; Sato, K.; Ishikawa, Y.; Yamamura, K.; Kawabata, N.; Ikeda, H.; Kamada, K.

2013-05-01

We report the development of a high spatial resolution tweezers-type coincidence gamma-ray camera for medical imaging. This application consists of large-area monolithic Multi-Pixel Photon Counters (MPPCs) and submillimeter pixelized scintillator matrices. The MPPC array has 4 × 4 channels with a three-side buttable, very compact package. For typical operational gain of 7.5 × 105 at + 20 °C, gain fluctuation over the entire MPPC device is only ± 5.6%, and dark count rates (as measured at the 1 p.e. level) amount to <= 400 kcps per channel. We selected Ce-doped (Lu,Y)2(SiO4)O (Ce:LYSO) and a brand-new scintillator, Ce-doped Gd3Al2Ga3O12 (Ce:GAGG) due to their high light yield and density. To improve the spatial resolution, these scintillators were fabricated into 15 × 15 matrices of 0.5 × 0.5 mm2 pixels. The Ce:LYSO and Ce:GAGG scintillator matrices were assembled into phosphor sandwich (phoswich) detectors, and then coupled to the MPPC array along with an acrylic light guide measuring 1 mm thick, and with summing operational amplifiers that compile the signals into four position-encoded analog outputs being used for signal readout. Spatial resolution of 1.1 mm was achieved with the coincidence imaging system using a 22Na point source. These results suggest that the gamma-ray imagers offer excellent potential for applications in high spatial medical imaging.

Cross-Talk Limits of Highly Segmented Semiconductor Detectors

NASA Astrophysics Data System (ADS)

Pullia, Alberto; Weisshaar, Dirk; Zocca, Francesca; Bazzacco, Dino

2011-06-01

Cross-talk limits of monolithic highly-segmented semiconductor detectors for high-resolution X-gamma spectrometry are investigated. Cross-talk causes false signal components yielding amplitude losses and fold-dependent shifts of the spectral lines, which partially spoil the spectroscopic performance of the detector. Two complementary electrical models are developed, which describe quantitatively the inter-channel cross-talk of monolithic segmented detectors whose electrodes are read out by charge-sensitive preamplifiers. The first is here designated as Cross-Capacitance (CC) model, the second as Split-Charge (SC) model. The CC model builds around the parasitic capacitances Cij linking the preamplifier outputs and the neighbor channel inputs. The SC model builds around the finite-value of the decoupling capacitance CC used to read out the high-voltage detector electrode. The key parameters of the models are individuated and ideas are shown to minimize their impact. Using a quasi-coaxial germanium segmented detector it is found that the SC cross-talk becomes negligible for decoupling capacitances larger than 1 nF, where instead the CC cross-talk tends to dominate. The residual cross-talk may be reduced by minimization of stray capacitances Cij, through a careful design of the layout of the Printed Circuit Board (PCB) where the input transistors are mounted. Cij can be made as low as 5 fF, but it is shown that even in such case the impact of the CC cross-talk on the detector performance is not negligible. Finally, an algorithm for cross-talk correction is presented and elaborated.

Coherent UDWDM PON with joint subcarrier reception at OLT.

PubMed

Kottke, Christoph; Fischer, Johannes Karl; Elschner, Robert; Frey, Felix; Hilt, Jonas; Schubert, Colja; Schmidt, Daniel; Wu, Zifeng; Lankl, Berthold

2014-07-14

In this contribution, we report on the experimental investigation of an ultra-dense wavelength-division multiplexing (UDWDM) upstream link with up to 700 × 2.488 Gb/s polarization-division multiplexing differential quadrature phase-shift keying parallel upstream user channels transmitted over 80 km of standard single-mode fiber. We discuss challenges of the digital signal processing in the optical line terminal arising from the joint reception of several upstream user channels. We present solutions for resource and cost-efficient realization of the required channel separation, matched filtering, down-conversion and decimation as well as realization of the clock recovery and polarization demultiplexing for each individual channel.

A Huygens Surface Approach to Antenna Implementation in Near-Field Radar Imaging System Simulations

DTIC Science & Technology

2015-08-01

environment. The model consists of an ultra - wideband , forward-looking radar imaging system, equipped with a multi-static antenna array and mounted on a...of the receiving antenna. 2.2 Huygens Surface Implementation Details The NAFDTD code implements the excitation waveform as a short, ultra - wideband ...

Non-filamentated ultra-intense and ultra-short pulse fronts in three-dimensional Raman seed amplification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lehmann, G.; Spatschek, K. H.

Ultra-intense and ultra-short laser pulses may be generated up to the exawatt-zetawatt regime due to parametric processes in plasmas. The minimization of unwanted plasma processes leads to operational limits which are discussed here with respect to filamentation. Transverse filamentation, which originally was derived for plane waves, is being investigated for seed pulse propagation in the so called π-pulse limit. A three-dimensional (3D) three-wave-interaction model is the basis of the present investigation. To demonstrate the applicability of the three-wave-interaction model, the 1D pulse forms are compared with those obtained from 1D particle in cell and Vlasov simulations. Although wave-breaking may occur,more » the kinetic simulations show that the leading pumped pulse develops a form similar to that obtained from the three-wave-interaction model. In the main part, 2D and 3D filamentation processes of (localized) pulses are investigated with the three-wave-interaction model. It is shown that the leading pulse front can stay filamentation-free, whereas the rear parts show transverse modulations.« less

Development and Evaluation of High Bioavailable Sustained-Release Nimodipine Tablets Prepared with Monolithic Osmotic Pump Technology.

PubMed

Kong, Hua; Yu, Fanglin; Liu, Yan; Yang, Yang; Li, Mingyuan; Cheng, Xiaohui; Hu, Xiaoqin; Tang, Xuemei; Li, Zhiping; Mei, Xingguo

2018-01-01

Frequent administration caused by short half-life and low bioavailability due to poor solubility and low dissolution rate limit the further application of poorly water-soluble nimodipine, although several new indications have been developed. To overcome these shortcomings, sophisticated technologies had to be used since the dose of nimodipine was not too low and the addition of solubilizers could not resolve the problem of poor release. The purpose of this study was to obtain sustained and complete release of nimodipine with a simple and easily industrialized technology. The expandable monolithic osmotic pump tablets containing nimodipine combined with poloxamer 188 and carboxymethylcellulose sodium were prepared. The factors affecting drug release including the amount of solubilizing agent, expanding agent, retarding agent in core tablet and porogenic agent in semipermeable film were optimized. The release behavior was investigated both in vitro and in beagle dogs. It was proved that the anticipant release of nimodipine could be realized in vitro. The sustained and complete release of nimodipine was also realized in beagles because the mean residence time of nimodipine from the osmotic pump system was longer and Cmax was lower than those from the sustained-release tablets in market while there was no difference in AUC(0-t) of the monolithic osmotic pump tablets and the sustained release tablets in market. It was reasonable to believe that the sustained and complete release of poorly watersoluble nimodipine could be realized by using simple expandable monolithic osmotic pump technology combined with surfactant. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Short Large-Amplitude Magnetic Structures (SLAMS) at Venus

NASA Technical Reports Server (NTRS)

Collinson, G. A.; Wilson, L. B.; Sibeck, D. G.; Shane, N.; Zhang, T. L.; Moore, T. E.; Coates, A. J.; Barabash, S.

2012-01-01

We present the first observation of magnetic fluctuations consistent with Short Large-Amplitude Magnetic Structures (SLAMS) in the foreshock of the planet Venus. Three monolithic magnetic field spikes were observed by the Venus Express on the 11th of April 2009. The structures were approx.1.5->11s in duration, had magnetic compression ratios between approx.3->6, and exhibited elliptical polarization. These characteristics are consistent with the SLAMS observed at Earth, Jupiter, and Comet Giacobini-Zinner, and thus we hypothesize that it is possible SLAMS may be found at any celestial body with a foreshock.

Atomistic simulations of ultra-short pulse laser ablation of aluminum: validity of the Lambert-Beer law

NASA Astrophysics Data System (ADS)

Eisfeld, Eugen; Roth, Johannes

2018-05-01

Based on hybrid molecular dynamics/two-temperature simulations, we study the validity of the application of Lambert-Beer's law, which is conveniently used in various modeling approaches of ultra-short pulse laser ablation of metals. The method is compared to a more rigorous treatment, which involves solving the Helmholtz wave equation for different pulse durations ranging from 100 fs to 5 ps and a wavelength of 800 nm. Our simulations show a growing agreement with increasing pulse durations, and we provide appropriate optical parameters for all investigated pulse durations.

Ultra-wideband short-pulse radar with range accuracy for short range detection

DOEpatents

Rodenbeck, Christopher T; Pankonin, Jeffrey; Heintzleman, Richard E; Kinzie, Nicola Jean; Popovic, Zorana P

2014-10-07

An ultra-wideband (UWB) radar transmitter apparatus comprises a pulse generator configured to produce from a sinusoidal input signal a pulsed output signal having a series of baseband pulses with a first pulse repetition frequency (PRF). The pulse generator includes a plurality of components that each have a nonlinear electrical reactance. A signal converter is coupled to the pulse generator and configured to convert the pulsed output signal into a pulsed radar transmit signal having a series of radar transmit pulses with a second PRF that is less than the first PRF.

Carrier-envelope phase control using linear electro-optic effect.

PubMed

Gobert, O; Paul, P M; Hergott, J F; Tcherbakoff, O; Lepetit, F; 'Oliveira, P D; Viala, F; Comte, M

2011-03-14

We present a new method to control the Carrier-Envelope Phase of ultra-short laser pulses by using the linear Electro-Optic Effect. Experimental demonstration is carried out on a Chirped Pulse Amplification based laser. Phase shifts greater than π radian can be obtained by applying moderate voltage on a LiNbO3 crystal with practically no changes to all other parameters of the pulse with the exception of its group delay. Time response of the Electro-Optic effect makes possible shaping at a high repetition rate or stabilization of the CEP of ultra short CPA laser systems.

A two-dimensional analytical modeling for channel potential and threshold voltage of short channel triple material symmetrical gate Stack (TMGS) DG-MOSFET

NASA Astrophysics Data System (ADS)

Tripathi, Shweta

2016-10-01

In the present work, a two-dimensional (2D) analytical framework of triple material symmetrical gate stack (TMGS) DG-MOSFET is presented in order to subdue the short channel effects. A lightly doped channel along with triple material gate having different work functions and symmetrical gate stack structure, showcases substantial betterment in quashing short channel effects to a good extent. The device functioning amends in terms of improved exemption to threshold voltage roll-off, thereby suppressing the short channel effects. The encroachments of respective device arguments on the threshold voltage of the proposed structure are examined in detail. The significant outcomes are compared with the numerical simulation data obtained by using 2D ATLAS™ device simulator to affirm and formalize the proposed device structure.

High-pressure microfluidic control in lab-on-a-chip devices using mobile polymer monoliths.

PubMed

Hasselbrink, Ernest F; Shepodd, Timothy J; Rehm, Jason E

2002-10-01

We have developed a nonstick polymer formulation for creating moving parts inside of microfluidic channels and have applied the technique to create piston-based devices that overcome several microfluidic flow control challenges. The parts were created bycompletely filling the channels of a glass microfluidic chip with the monomer/ solvent/initiator components of a nonstick photopolymer and then selectively exposing the chip to UV light in order to define mobile pistons (or other quasi-two-dimensional shapes) inside the channels. Stops defined in the substrate prevent the part from flushing out of the device but also provide sealing surfaces so that valves and other flow control devices are possible. Sealing against pressures greater than 30 MPa (4,500 psi) and actuation times less than 33 ms are observed. An on-chip check valve, a diverter valve, and a 10-nL pipet are demonstrated. This valving technology, coupled with high-pressure electrokinetic pumps, should make it possible to create a completely integrated HPLC system on a chip.

Advanced Mirror Technology Development (AMTD) Project: Overview and Year 4 Accomplishments

NASA Technical Reports Server (NTRS)

Stahl, H. Philip

2016-01-01

The Advanced Mirror Technology Development (AMTD) project is in Phase 2 of a multiyear effort initiated in Fiscal Year (FY) 2012, to mature toward the next Technology Readiness Level (TRL) critical technologies required to enable 4-m-or-larger monolithic or segmented ultraviolet, optical, and infrared (UVOIR) space telescope primary-mirror assemblies for general astrophysics and ultra-high-contrast observations of exoplanets. Key hardware accomplishments of 2015/16 are the successful low-temperature fusion of a 1.5-meter diameter ULE mirror that is a 1/3rd scale model of a 4-meter mirror and the initiation of polishing of a 1.2-meter Extreme-Lightweight Zerodur mirror. Critical to AMTD's success is an integrated team of scientists, systems engineers, and technologists; and a science-driven systems engineering approach.

Advanced Mirror Technology Development (AMTD) project: overview and year four accomplishments

NASA Astrophysics Data System (ADS)

Stahl, H. Philip

2016-07-01

The Advanced Mirror Technology Development (AMTD) project is in Phase 2 of a multiyear effort initiated in Fiscal Year (FY) 2012, to mature toward the next Technology Readiness Level (TRL) critical technologies required to enable 4-m-or-larger monolithic or segmented ultraviolet, optical, and infrared (UVOIR) space telescope primary-mirror assemblies for general astrophysics and ultra-high-contrast observations of exoplanets. Key hardware accomplishments of 2015/16 are the successful low-temperature fusion of a 1.5-meter diameter ULE mirror that is a 1/3rd scale model of a 4-meter mirror and the initiation of polishing of a 1.2-meter Extreme-Lightweight Zerodur mirror. Critical to AMTD's success is an integrated team of scientists, systems engineers, and technologists; and a science-driven systems engineering approach.

8-channel prototype of SALT readout ASIC for Upstream Tracker in the upgraded LHCb experiment

NASA Astrophysics Data System (ADS)

Abellan Beteta, C.; Bugiel, S.; Dasgupta, R.; Firlej, M.; Fiutowski, T.; Idzik, M.; Kane, C.; Moron, J.; Swientek, K.; Wang, J.

2017-02-01

SALT is a new 128-channel readout ASIC for silicon strip detectors in the upgraded Upstream Tracker of the LHCb experiment. It will extract and digitise analogue signals from the sensor, perform digital processing and transmit serial output data. SALT is designed in CMOS 130 nm process and uses a novel architecture comprising of an analogue front-end and an ultra-low power (<0.5 mW) fast (40 MSps) sampling 6-bit ADC in each channel. An 8-channel prototype (SALT8), comprising all important functionalities was designed, fabricated and tested. A full 128-channel version was also submitted. The design and test results of the SALT8 prototype are presented showing its full functionality.

A Novel Method for gamma - text{photons} Depth-of-Interaction Detection in Monolithic Scintillation Crystals

NASA Astrophysics Data System (ADS)

Pani, Roberto; Bettiol, Marco; Preziosi, Enrico; Borrazzo, Cristian; Pellegrini, Rosanna; González, Antonio J.; Conde, Pablo; Cinti, Maria Nerina; Fabbri, Andrea; Di Castro, Elisabetta; Majewski, Stan

2016-10-01

Achieved spatial resolution of the PET systems is often limited by the parallax error due to the lack of information about the Depth of Interaction (DoI) inside the crystal of the incoming 511 keV annihilation photons. The smaller the diameter of the PET ring and the thicker the scintillator are, the more this error affects imaging performance. In this work, a DoI calculator suitable for monolithic scintillation crystals and based on the shape of the scintillation light distribution at the photodetector surface has been proposed. To test the estimator performance, a test PET module with a 50 × 50 × 20 mm monolithic LYSO crystal coupled to a 12 × 12 SiPM array has been employed. In addition, for calibration and validation of the method, Geant4 simulations have been also used. The key result of the application of the proposed DoI estimator is obtaining a continuous DoI estimation with an average DoI resolution of about 5 mm in the 20 mm-thick crystal. Benefiting from the DoI estimation capabilities of the method, it has been also possible to achieve additional important goals, first of all reducing the parallax error. First, because the scintillation light collection varies as a function of the 3D position of the interaction of the annihilation photon inside the crystal, a method to correct this response variation via a proper 3D look-up-table is proposed. This has led to an improvement of about 35% in energy resolution. Moreover, a DoI-dependent position algorithm has been proposed, allowing an improvement of both planar (X-Y) position linearity and planar spatial resolution. This algorithm is specifically developed for the rows/columns multi-channel readout logic, that reduces the number of independent channels from N × N to N + N, where N is the number of SiPM photodetection elements (12 in our case) in each row and column. This development was performed in the framework of the MindView PET/MilI brain imaging project.

Experiment and Reactive-Burn Modeling in the RDX Based Explosive XTX 8004

NASA Astrophysics Data System (ADS)

Johnson, Carl; Murphy, Mike; Gustavsen, Rick; Jackson, Scott; Vincent, Samuel

2015-06-01

XTX 8004 consists of 80 wt. % cyclotrimethylenetrinitramine (RDX), and 20 wt. % Sylgard 182, a silicone rubber used as a binder. Nominal density is 1.5 g/cm3. Uncured XTX 8004 is putty like and can be molded or extruded. The XTX 8004 detonation product Hugoniot calibration was obtained from cylinder tests using a genetic algorithm approach to parameterize a Jones-Wilkins-Lee (JWL) equation of state. Additionally, we conducted four gas-gun experiments that were instrumented with embedded electromagnetic particle velocity gauges. These provided wave profiles to which we calibrated an Ignition and Growth reactive burn (IGRB) model in ALE3D for 1-D shock to detonation transitions. Further, acceptor and donor XTX 8004 were extruded into opposite sides of a monolithic polymethylmethacrylate (PMMA) block with a known thickness of PMMA forming the attenuator plate, the so-called monolithic gap test (MGT). Detonation and initiation in the XTX 8004 was recorded using multiple ultra-high-speed images of the position of the shock front in the PMMA. Input to the acceptor charge was estimated from stress wave profiles photographed inside the attenuator as well as with photonic Doppler velocimetry (PDV) measurements of the free surface velocity beneath the attenuator plate. Results were simulated using IGRB in ALE3D. Parameterization of IGRB to 1-D vs. 2-D experiments will be discussed.

Development of the Monolith Froth Reactor for Catalytic Wet Oxidation of CELSS Model Wastes

NASA Technical Reports Server (NTRS)

Abraham, Martin; Fisher, John W.

1995-01-01

The aqueous phase oxidation of acetic acid, used as a model compound for the treatment of CELSS (Controlled Ecological Life Support System) waste, was carried out in the monolith froth reactor which utilizes two-phase flow in the monolith channels. The catalytic oxidation of acetic acid was carried out over a Pt/Al2O3 catalyst, prepared at The University of Tulsa, at temperatures and pressures below the critical point of water. The effect of externally controllable parameters (temperature, liquid flow rate, distributor plate orifice size, pitch, and catalyst distance from the distributor plate) on the rate of acetic acid oxidation was investigated. Results indicate reaction rate increased with increasing temperature and exhibited a maximum with respect to liquid flow rate. The apparent activation energy calculated from reaction rate data was 99.7 kJ/mol. This value is similar to values reported for the oxidation of acetic acid in other systems and is comparable to intrinsic values calculated for oxidation reactions. The kinetic data were modeled using simple power law kinetics. The effect of "froth" feed system characteristics was also investigated. Results indicate that the reaction rate exhibits a maximum with respect to distributor plate orifice size, pitch, and catalyst distance from the distributor plate. Fundamental results obtained were used to extrapolate where the complete removal of acetic acid would be obtained and for the design and operation of a full scale CELSS treatment system.

Performance Analysis of IEEE 802.15.6 CSMA/CA Protocol for WBAN Medical Scenario through DTMC Model.

PubMed

Kumar, Vivek; Gupta, Bharat

2016-12-01

The newly drafted IEEE 802.15.6 standard for Wireless Body Area Networks (WBAN) has been concentrating on a numerous medical and non-medical applications. Such short range wireless communication standard offers ultra-low power consumption with variable data rates from few Kbps to Mbps in, on or around the proximity of the human body. In this paper, the performance analysis of carrier sense multiple access with collision avoidance (CSMA/CA) scheme based on IEEE 802.15.6 standard in terms of throughput, reliability, clear channel assessment (CCA) failure probability, packet drop probability, and end-to-end delay has been presented. We have developed a discrete-time Markov chain (DTMC) to significantly evaluate the performances of IEEE 802.15.6 CSMA/CA under non-ideal channel condition having saturated traffic condition including node wait time and service time. We also visualize that, as soon as the payload length increases the CCA failure probability increases, which results in lower node's reliability. Also, we have calculated the end-to-end delay in order to prioritize the node wait time cause by backoff and retransmission. The user priority (UP) wise DTMC analysis has been performed to show the importance of the standard especially for medical scenario.

Achievable rate degradation of ultra-wideband coherent fiber communication systems due to stimulated Raman scattering.

PubMed

Semrau, Daniel; Killey, Robert; Bayvel, Polina

2017-06-12

As the bandwidths of optical communication systems are increased to maximize channel capacity, the impact of stimulated Raman scattering (SRS) on the achievable information rates (AIR) in ultra-wideband coherent WDM systems becomes significant, and is investigated in this work, for the first time. By modifying the GN-model to account for SRS, it is possible to derive a closed-form expression that predicts the optical signal-to-noise ratio of all channels at the receiver for bandwidths of up to 15 THz, which is in excellent agreement with numerical calculations. It is shown that, with fixed modulation and coding rate, SRS leads to a drop of approximately 40% in achievable information rates for bandwidths higher than 15 THz. However, if adaptive modulation and coding rates are applied across the entire spectrum, this AIR reduction can be limited to only 10%.

Monolithic fuel injector and related manufacturing method

DOEpatents

Ziminsky, Willy Steve [Greenville, SC; Johnson, Thomas Edward [Greenville, SC; Lacy, Benjamin [Greenville, SC; York, William David [Greenville, SC; Stevenson, Christian Xavier [Greenville, SC

2012-05-22

A monolithic fuel injection head for a fuel nozzle includes a substantially hollow vesicle body formed with an upstream end face, a downstream end face and a peripheral wall extending therebetween, an internal baffle plate extending radially outwardly from a downstream end of the bore, terminating short of the peripheral wall, thereby defining upstream and downstream fuel plenums in the vesicle body, in fluid communication by way of a radial gap between the baffle plate and the peripheral wall. A plurality of integral pre-mix tubes extend axially through the upstream and downstream fuel plenums in the vesicle body and through the baffle plate, with at least one fuel injection hole extending between each of the pre-mix tubes and the upstream fuel plenum, thereby enabling fuel in the upstream plenum to be injected into the plurality of pre-mix tubes. The fuel injection head is formed by direct metal laser sintering.

Monolithic MZI-SOA hybrid switch for low-power and low-penalty operation.

PubMed

Cheng, Q; Wonfor, A; Wei, J L; Penty, R V; White, I H

2014-03-15

We report the first experimental demonstration of a monolithically integrated hybrid dilated 2×2 modular optical switch using Mach-Zehnder modulators as low-loss 1×2 switching elements and short semiconductor optical amplifiers to provide additional extinction and gain. An excellent 40 dB cross-talk/extinction ratio is recorded with data-modulated signal-to-noise ratios of up to 44 dB in a 0.1 nm bandwidth. A switching time of 3 ns is demonstrated. Bit error rate studies show extremely low subsystem penalties of less than 0.1 dB, and studies indicate that, by using this hybrid switch building block, an 8×8 port switch could be achieved with 14 dB input power dynamic range for subsystem penalties of less than 0.5 dB.

Monolithic short wave infrared (SWIR) detector array

NASA Technical Reports Server (NTRS)

1983-01-01

A monolithic self-scanned linear detector array was developed for remote sensing in the 1.1- 2.4-micron spectral region. A high-density IRCCD test chip was fabricated to verify new design approaches required for the detector array. The driving factors in the Schottky barrier IRCCD (Pdsub2Si) process development are the attainment of detector yield, uniformity, adequate quantum efficiency, and lowest possible dark current consistent with radiometric accuracy. A dual-band module was designed that consists of two linear detector arrays. The sensor architecture places the floating diffusion output structure in the middle of the chip, away from the butt edges. A focal plane package was conceptualized and includes a polycrystalline silicon substrate carrying a two-layer, thick-film interconnecting conductor pattern and five epoxy-mounted modules. A polycrystalline silicon cover encloses the modules and bond wires, and serves as a radiation and EMI shield, thermal conductor, and contamination seal.

Miniaturized ultrasound imaging probes enabled by CMUT arrays with integrated frontend electronic circuits.

PubMed

Khuri-Yakub, B T; Oralkan, Omer; Nikoozadeh, Amin; Wygant, Ira O; Zhuang, Steve; Gencel, Mustafa; Choe, Jung Woo; Stephens, Douglas N; de la Rama, Alan; Chen, Peter; Lin, Feng; Dentinger, Aaron; Wildes, Douglas; Thomenius, Kai; Shivkumar, Kalyanam; Mahajan, Aman; Seo, Chi Hyung; O'Donnell, Matthew; Truong, Uyen; Sahn, David J

2010-01-01

Capacitive micromachined ultrasonic transducer (CMUT) arrays are conveniently integrated with frontend integrated circuits either monolithically or in a hybrid multichip form. This integration helps with reducing the number of active data processing channels for 2D arrays. This approach also preserves the signal integrity for arrays with small elements. Therefore CMUT arrays integrated with electronic circuits are most suitable to implement miniaturized probes required for many intravascular, intracardiac, and endoscopic applications. This paper presents examples of miniaturized CMUT probes utilizing 1D, 2D, and ring arrays with integrated electronics.

Green approach using monolithic column for simultaneous determination of coformulated drugs.

PubMed

Yehia, Ali M; Mohamed, Heba M

2016-06-01

Green chemistry and sustainability is now entirely encompassed across the majority of pharmaceutical companies and research labs. Researchers' attention is careworn toward implementing the green analytical chemistry principles for more eco-friendly analytical methodologies. Solvents play a dominant role in determining the greenness of the analytical procedure. Using safer solvents, the greenness profile of the methodology could be increased remarkably. In this context, a green chromatographic method has been developed and validated for the simultaneous determination of phenylephrine, paracetamol, and guaifenesin in their ternary pharmaceutical mixture. The chromatographic separation was carried out using monolithic column and green solvents as mobile phase. The use of monolithic column allows efficient separation protocols at higher flow rates, which results in short time of analysis. Two-factor three-level experimental design was used to optimize the chromatographic conditions. The greenness profile of the proposed methodology was assessed using eco-scale as a green metrics and was found to be an excellent green method with regard to the usage and production of hazardous chemicals and solvents, energy consumption, and amount of produced waste. The proposed method improved the environmental impact without compromising the analytical performance criteria and could be used as a safer alternate for the routine analysis of the studied drugs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Monolithic Hydrogen Peroxide Catalyst Bed Development

NASA Technical Reports Server (NTRS)

Ponzo, J. B.

2003-01-01

With recent increased industry and government interest in rocket grade hydrogen peroxide as a viable propellant, significant effort has been expended to improve on earlier developments. This effort has been predominately centered in improving heterogeneous. typically catalyst beds; and homogeneous catalysts, which are typically solutions of catalytic substances. Heterogeneous catalyst beds have traditionally consisted of compressed wire screens plated with a catalytic substance, usually silver, and were used m many RCS applications (X-1, Mercury, and Centaur for example). Aerojet has devised a heterogeneous catalyst design that is monolithic (single piece), extremely compact, and has pressure drops equal to or less than traditional screen beds. The design consists of a bonded stack of very thin, photoetched metal plates, silver coated. This design leads to a high surface area per unit volume and precise flow area, resulting in high, stable, and repeatable performance. Very high throughputs have been demonstrated with 90% hydrogen peroxide. (0.60 lbm/s/sq in at 1775-175 psia) with no flooding of the catalyst bed. Bed life of over 900 seconds has also been demonstrated at throughputs of 0.60 lbm/s/sq in across varying chamber pressures. The monolithic design also exhibits good starting performance, short break-in periods, and will easily scale to various sizes.

Ultra-short heart rate variability recording reliability: The effect of controlled paced breathing.

PubMed

Melo, Hiago M; Martins, Thiago C; Nascimento, Lucas M; Hoeller, Alexandre A; Walz, Roger; Takase, Emílio

2018-06-04

Recent studies have reported that Heart Rate Variability (HRV) indices remain reliable even during recordings shorter than 5 min, suggesting the ultra-short recording method as a valuable tool for autonomic assessment. However, the minimum time-epoch to obtain a reliable record for all HRV domains (time, frequency, and Poincare geometric measures), as well as the effect of respiratory rate on the reliability of these indices remains unknown. Twenty volunteers had their HRV recorded in a seated position during spontaneous and controlled respiratory rhythms. HRV intervals with 1, 2, and 3 min were correlated with the gold standard period (6-min duration) and the mean values of all indices were compared in the two respiratory rhythm conditions. rMSSD and SD1 were more reliable for recordings with ultra-short duration at all time intervals (r values from 0.764 to 0.950, p < 0.05) for spontaneous breathing condition, whereas the other indices require longer recording time to obtain reliable values. The controlled breathing rhythm evokes stronger r values for time domain indices (r values from 0.83 to 0.99, p < 0.05 for rMSSD), but impairs the mean values replicability of domains across most time intervals. Although the use of standardized breathing increases the correlations coefficients, all HRV indices showed an increase in mean values (t values from 3.79 to 14.94, p < 0.001) except the RR and HF that presented a decrease (t = 4.14 and 5.96, p < 0.0001). Our results indicate that proper ultra-short-term recording method can provide a quick and reliable source of cardiac autonomic nervous system assessment. © 2018 Wiley Periodicals, Inc.

Dynamic and interaction of fs-laser induced cavitation bubbles for analyzing the cutting effect

NASA Astrophysics Data System (ADS)

Tinne, N.; Schumacher, S.; Nuzzo, V.; Ripken, T.; Lubatschowski, H.

2009-07-01

A prominent laser based treatment in ophthalmology is the LASIK procedure which nowadays includes a cutting of the corneal tissue based on ultra short pulses. Focusing an ultra short laser pulse below the surface of biological tissue an optical breakdown is caused and hence a dissection is obtained. The laser energy of the laser pulses is absorbed by nonlinear processes. As a result a cavitation bubble expands and ruptures the tissue. Hence positioning of several optical breakdowns side by side generates an incision. Due to a reduction of the duration of the treatment the current development of ultra short laser systems points to higher repetition rates in the range of hundreds of KHz or even MHz instead of tens of kHz. This in turn results in a probable occurrence of interaction between different optical breakdowns and respectively cavitation bubbles of adjacent optical breakdowns. While the interaction of one single laser pulse with biological tissue is analyzed reasonably well experimentally and theoretically, the interaction of several spatial and temporal following pulses is scarcely determined yet. Thus the aim of this study is to analyse the dynamic and interaction of two cavitation bubbles by using high speed photography. The applied laser pulse energy, the energy ratio and the spot distance between different cavitation bubbles were varied. Depending on a change of these parameters different kinds of interactions such as a flattening and deformation of bubble shape or jet formation are observed. Based on these results a further research seems to be inevitable to comprehend and optimize the cutting effect of ultra short pulse laser systems with high (> 1 MHz) repetition rates.

Adaptive suppression of power line interference in ultra-low field magnetic resonance imaging in an unshielded environment

NASA Astrophysics Data System (ADS)

Huang, Xiaolei; Dong, Hui; Qiu, Yang; Li, Bo; Tao, Quan; Zhang, Yi; Krause, Hans-Joachim; Offenhäusser, Andreas; Xie, Xiaoming

2018-01-01

Power-line harmonic interference and fixed-frequency noise peaks may cause stripe-artifacts in ultra-low field (ULF) magnetic resonance imaging (MRI) in an unshielded environment and in a conductively shielded room. In this paper we describe an adaptive suppression method to eliminate these artifacts in MRI images. This technique utilizes spatial correlation of the interference from different positions, and is realized by subtracting the outputs of the reference channel(s) from those of the signal channel(s) using wavelet analysis and the least squares method. The adaptive suppression method is first implemented to remove the image artifacts in simulation. We then experimentally demonstrate the feasibility of this technique by adding three orthogonal superconducting quantum interference device (SQUID) magnetometers as reference channels to compensate the output of one 2nd-order gradiometer. The experimental results show great improvement in the imaging quality in both 1D and 2D MRI images at two common imaging frequencies, 1.3 kHz and 4.8 kHz. At both frequencies, the effective compensation bandwidth is as high as 2 kHz. Furthermore, we examine the longitudinal relaxation times of the same sample before and after compensation, and show that the MRI properties of the sample did not change after applying adaptive suppression. This technique can effectively increase the imaging bandwidth and be applied to ULF MRI detected by either SQUIDs or Faraday coil in both an unshielded environment and a conductively shielded room.

Optimal packing for cascaded regenerative transmission based on phase sensitive amplifiers.

PubMed

Sorokina, Mariia; Sygletos, Stylianos; Ellis, Andrew D; Turitsyn, Sergei

2013-12-16

We investigate the transmission performance of advanced modulation formats in nonlinear regenerative channels based on cascaded phase sensitive amplifiers. We identify the impact of amplitude and phase noise dynamics along the transmission line and show that after a cascade of regenerators, densely packed single ring PSK constellations outperform multi-ring constellations. The results of this study will greatly simplify the design of future nonlinear regenerative channels for ultra-high capacity transmission.

Magnetospheric Truncation, Tidal Inspiral, and the Creation of Short-period and Ultra-short-period Planets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Eve J.; Chiang, Eugene, E-mail: evelee@berkeley.edu

Sub-Neptunes around FGKM dwarfs are evenly distributed in log orbital period down to ∼10 days, but dwindle in number at shorter periods. Both the break at ∼10 days and the slope of the occurrence rate down to ∼1 day can be attributed to the truncation of protoplanetary disks by their host star magnetospheres at corotation. We demonstrate this by deriving planet occurrence rate profiles from empirical distributions of pre-main-sequence stellar rotation periods. Observed profiles are better reproduced when planets are distributed randomly in disks—as might be expected if planets formed in situ—rather than piled up near disk edges, as wouldmore » be the case if they migrated in by disk torques. Planets can be brought from disk edges to ultra-short (<1 day) periods by asynchronous equilibrium tides raised on their stars. Tidal migration can account for how ultra-short-period planets are more widely spaced than their longer-period counterparts. Our picture provides a starting point for understanding why the sub-Neptune population drops at ∼10 days regardless of whether the host star is of type FGK or early M. We predict planet occurrence rates around A stars to also break at short periods, but at ∼1 day instead of ∼10 days because A stars rotate faster than stars with lower masses (this prediction presumes that the planetesimal building blocks of planets can drift inside the dust sublimation radius).« less

Shrink film patterning by craft cutter: complete plastic chips with high resolution/high-aspect ratio channel.

PubMed

Taylor, Douglas; Dyer, David; Lew, Valerie; Khine, Michelle

2010-09-21

This paper presents a rapid, ultra-low-cost approach to fabricate microfluidic devices using a polyolefin shrink film and a digital craft cutter. The shrinking process (with a 95% reduction in area) results in relatively uniform and consistent microfluidic channels with smooth surfaces, vertical sidewalls, and high aspect ratio channels with lateral resolutions well beyond the tool used to cut them. The thermal bonding of the layers results in strongly bonded devices. Complex microfluidic designs are easily designed on the fly and protein assays are also readily integrated into the device. Full device characterization including channel consistency, optical properties, and bonding strength are assessed in this technical note.

Ultrasmall multi-channel resonant-tunneling filter using mode gap of width-tuned photonic-crystal waveguide.

PubMed

Shinya, Akihiko; Mitsugi, Satoshi; Kuramochi, Eiichi; Notomi, Masaya

2005-05-30

We have devised an ultra-small multi-channel drop filter based on a two-port resonant tunneling system in a two-dimensional photonic crystal with a triangular air-hole lattice. This filter does not require careful consideration of the interference process to achieve a high dropping efficiency. First we develop three-port systems based on a two-port resonant tunneling filter. Next we devise a multi-port channel drop filter by cascading these three-port systems. In this paper, we demonstrate a ten-channel drop filter with an 18 mum device size by 2D-FDTD calculation, and a three-port resonant tunneling filter with 65+/- 20 % dropping efficiency by experiment.

Gas bubble formation in fused silica generated by ultra-short laser pulses.

PubMed

Cvecek, Kristian; Miyamoto, Isamu; Schmidt, Michael

2014-06-30

During processing of glass using ultra-fast lasers the formation of bubble-like structures can be observed in several glass types such as fused silica. Their formation can be exploited to generate periodic gratings in glasses but for other glass processing techniques such as waveguide-writing or glass welding by ultra-fast lasers the bubble formation proves often detrimental. In this work we present experiments and their results in order to gain understanding of the origins and on the underlying formation and transportation mechanisms of the gas bubbles.

Ultralow-power complementary metal-oxide-semiconductor inverters constructed on Schottky barrier modified nanowire metal-oxide-semiconductor field-effect-transistors.

PubMed

Ma, R M; Peng, R M; Wen, X N; Dai, L; Liu, C; Sun, T; Xu, W J; Qin, G G

2010-10-01

We show that the threshold voltages of both n- and p-channel metal-oxide-semiconductor field-effect-transistors (MOSFETs) can be lowered to close to zero by adding extra Schottky contacts on top of nanowires (NWs). Novel complementary metal-oxide-semiconductor (CMOS) inverters are constructed on these Schottky barrier modified n- and p-channel NW MOSFETs. Based on the high performances of the modified n- and p-channel MOSFETs, especially the low threshold voltages, the as-fabricated CMOS inverters have low operating voltage, high voltage gain, and ultra-low static power dissipation.

Rare-earth-ion-doped ultra-narrow-linewidth lasers on a silicon chip and applications to intra-laser-cavity optical sensing

NASA Astrophysics Data System (ADS)

Bernhardi, E. H.; de Ridder, R. M.; Wörhoff, K.; Pollnau, M.

2013-03-01

We report on diode-pumped distributed-feedback (DFB) and distributed-Bragg-reflector (DBR) channel waveguide lasers in Er-doped and Yb-doped Al2O3 on standard thermally oxidized silicon substrates. Uniform surface-relief Bragg gratings were patterned by laser-interference lithography and etched into the SiO2 top cladding. The maximum grating reflectivity exceeded 99%. Monolithic DFB and DBR cavities with Q-factors of up to 1.35×106 were realized. The Erdoped DFB laser delivered 3 mW of output power with a slope efficiency of 41% versus absorbed pump power. Singlelongitudinal- mode operation at a wavelength of 1545.2 nm was achieved with an emission line width of 1.70 0.58 kHz, corresponding to a laser Q-factor of 1.14×1011. Yb-doped DFB and DBR lasers were demonstrated at wavelengths near 1020 nm with output powers of 55 mW and a slope efficiency of 67% versus launched pump power. An Yb-doped dualwavelength laser was achieved based on the optical resonances induced by two local phase shifts in the DFB structure. A stable microwave signal at ~15 GHz with a -3-dB width of 9 kHz and a long-term frequency stability of +/- 2.5 MHz was created via the heterodyne photo-detection of the two laser wavelengths. By measuring changes in the microwave beat signal as the intra-cavity evanescent laser field interacts with micro-particles on the waveguide surface, we achieved real-time detection and accurate size measurement of single micro-particles with diameters ranging between 1 μm and 20 μm, which represents the typical size of many fungal and bacterial pathogens. A limit of detection of ~500 nm was deduced.

Gas-liquid two-phase flow behaviors and performance characteristics of proton exchange membrane fuel cells in a short-term microgravity environment

NASA Astrophysics Data System (ADS)

Guo, Hang; Liu, Xuan; Zhao, Jian Fu; Ye, Fang; Ma, Chong Fang

2017-06-01

In this work, proton exchange membrane fuel cells (PEMFCs) with transparent windows are designed to study the gas-liquid two-phase flow behaviors inside flow channels and the performance of a PEMFC with vertical channels and a PEMFC with horizontal channels in a normal gravity environment and a 3.6 s short-term microgravity environment. Experiments are conducted under high external circuit load and low external circuit load at low temperature where is 35 °C. The results of the present experimental work demonstrate that the performance and the gas-liquid two-phase flow behaviors of the PEMFC with vertical channels exhibits obvious changes when the PEMFCs enter the 3.6 s short-term microgravity environment from the normal gravity environment. Meanwhile, the performance of the PEMFC with vertical channels increases after the PEMFC enters the 3.6 s short-term microgravity environment under high external circuit load, while under low external circuit load, the PEMFC with horizontal channels exhibits better performance in both the normal gravity environment and the 3.6 s short-term microgravity environment.

2D-COS of in situ μ-Raman and in situ IR spectra for structure evolution characterisation of NEP-deposited cobalt oxide catalyst during n-nonane combustion

NASA Astrophysics Data System (ADS)

Chlebda, Damian K.; Jodłowski, Przemysław J.; Jędrzejczyk, Roman J.; Łojewska, Joanna

2017-11-01

New catalytic systems are still in development to meet the challenge of regulations concerning the emission of volatile organic compounds (VOCs). This is because such compounds have a significant impact on air quality and some of them are toxic to the environment and human beings. The catalytic combustion process of VOCs over non-noble metal catalysts is of great interest to researchers. The high conversion parameters and cost effective preparation makes them a valuable alternative to monoliths and noble metal catalysts. In this study, the cobalt catalyst was prepared by non-equilibrium plasma deposition of organic precursor on calcined kanthal steel. Thus prepared, cobalt oxide based microstructural short-channel reactors were tested for n-nonane combustion and the catalyst surfaces were examined by in situ μ-Raman spectroscopy and in situ infrared spectroscopy. The spectra collected at various temperatures were used in generalised two-dimensional correlation analysis to establish the sequential order of spectral intensity changes and correlate the simultaneous changes in bands selectively coupled by different interaction mechanisms. The 2D synchronous and asynchronous contour maps were proved to be a valuable extension to the standard analysis of the temperature dependent 1D spectra.

Monolithic mm-wave phase shifter using optically activated superconducting switches

NASA Technical Reports Server (NTRS)

Romanofsky, Robert R. (Inventor); Bhasin, Kul B. (Inventor)

1992-01-01

A phase shifter is disclosed having a reference path and a delay path, light sources, and superconductive switches. Each of the superconductive switches is terminated in a virtual short circuit, which may be a radial stub. Switching between the reference path and delayed path is accomplished by illuminating the superconductive switches connected to the desired path, while not illuminating the superconductive switches connected to the other path.

Methacrylate monolithic columns functionalized with epinephrine for capillary electrochromatography applications.

PubMed

Carrasco-Correa, Enrique Javier; Ramis-Ramos, Guillermo; Herrero-Martínez, José Manuel

2013-07-12

Epinephrine-bonded polymeric monoliths for capillary electrochromatography (CEC) were developed by nucleophilic substitution reaction of epoxide groups of poly(glycidyl-methacrylate-co-ethylenedimethacrylate) (poly(GMA-co-EDMA)) monoliths using epinephrine as nucleophilic reagent. The ring opening reaction under dynamic conditions was optimized. Successful chemical modification of the monolith surface was ascertained by in situ Raman spectroscopy characterization. In addition, the amount of epinephrine groups that was bound to the monolith surface was evaluated by oxidation of the catechol groups with Ce(IV), followed by spectrophotometric measurement of unreacted Ce(IV). About 9% of all theoretical epoxide groups of the parent monolith were bonded to epinephrine. The chromatographic behavior of the epinephrine-bonded monolith in CEC conditions was assessed with test mixtures of alkyl benzenes, aniline derivatives and substituted phenols. In comparison to the poly(GMA-co-EDMA) monoliths, the epinephrine-bonded monoliths exhibited a much higher retention and slight differences in selectivity. The epinephrine-bonded monolith was further modified by oxidation with a Ce(IV) solution and compared with the epinephrine-bonded monoliths. The resulting monolithic stationary phases were evaluated in terms of reproducibility, giving RSD values below 9% in the parameters investigated. Copyright © 2013 Elsevier B.V. All rights reserved.

Start-to-end simulation of single-particle imaging using ultra-short pulses at the European X-ray Free-Electron Laser

DOE PAGES

Fortmann-Grote, Carsten; Buzmakov, Alexey; Jurek, Zoltan; ...

2017-09-01

Single-particle imaging with X-ray free-electron lasers (XFELs) has the potential to provide structural information at atomic resolution for non-crystalline biomolecules. This potential exists because ultra-short intense pulses can produce interpretable diffraction data notwithstanding radiation damage. This paper explores the impact of pulse duration on the interpretability of diffraction data using comprehensive and realistic simulations of an imaging experiment at the European X-ray Free-Electron Laser. In conclusion, it is found that the optimal pulse duration for molecules with a few thousand atoms at 5 keV lies between 3 and 9 fs.

Ultra-short laser interactions with nanoparticles in different media: from electromagnetic to thermal and electrostatic effects

NASA Astrophysics Data System (ADS)

Itina, Tatiana E.

2017-02-01

Key issues of the controlled synthesis of nanoparticles and nanostructures, as well as laser-particle interactions are considered in the context of the latest applications appearing in many fields such as photonics, medicine, 3D printing, etc. The results of a multi-physics numerical study of laser interaction with nanoparticles will be presented in the presence of several environments. In particular, attention will be paid to the numerical study of laser interactions with heterogeneous materials (eg. colloidal liquids and/or nanoparticles in a dielectric medium) and the aggregation/sintering/fragmentation processes induced by ultra-short laser pulses.

Start-to-end simulation of single-particle imaging using ultra-short pulses at the European X-ray Free-Electron Laser

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fortmann-Grote, Carsten; Buzmakov, Alexey; Jurek, Zoltan

Single-particle imaging with X-ray free-electron lasers (XFELs) has the potential to provide structural information at atomic resolution for non-crystalline biomolecules. This potential exists because ultra-short intense pulses can produce interpretable diffraction data notwithstanding radiation damage. This paper explores the impact of pulse duration on the interpretability of diffraction data using comprehensive and realistic simulations of an imaging experiment at the European X-ray Free-Electron Laser. In conclusion, it is found that the optimal pulse duration for molecules with a few thousand atoms at 5 keV lies between 3 and 9 fs.

Ultra short laser pulse modification of wave guides

NASA Astrophysics Data System (ADS)

Rosenfeld, Arkadi; Ashkenasi, David

2003-11-01

The high peak powers of ultra short (ps and sub-ps) pulsed lasers available at relatively low single pulse energies potentially allow for a precise localization of photon energy, either on the surface or inside (transparent) materials. Three dimensional micro structuring of bulk transparent media without any sign of mechanical cracking has shown the potential of ultra short laser processing. In this study, the micro structuring of bulk transparent media was used to modify fused silica and especially the cladding-core interface in normal fused silica wave guides. The idea behind this technique is to enforce a local mismatch for total reflection at the interface at minimal mechanic stress to overcome the barrier for enhanced optical out-coupling. The laser-induced modifications were studied in dependence of pulse width, focal alignment, single pulse energy and pulse overlap. Micro traces with a thickness between 3 and 8 μm were generated with a spacing of 10 μm in the subsurface region using sub-ps and ps laser pulses at a wavelength of 800 nm. The optical leakage enforced by a micro spiral pattern is significant and can be utilized for medical applications or potentially also for telecommunications and fiber laser technology.

Multifunctional gold nanorods for selective plasmonic photothermal therapy in pancreatic cancer cells using ultra-short pulse near-infrared laser irradiation.

PubMed

Patino, Tania; Mahajan, Ujjwal; Palankar, Raghavendra; Medvedev, Nikolay; Walowski, Jakob; Münzenberg, Markus; Mayerle, Julia; Delcea, Mihaela

2015-03-12

Gold nanorods (AuNRs) have attracted considerable attention in plasmonic photothermal therapy for cancer treatment by exploiting their selective and localized heating effect due to their unique photophysical properties. Here we describe a strategy to design a novel multifunctional platform based on AuNRs to: (i) specifically target the adenocarcinoma MUC-1 marker through the use of the EPPT-1 peptide, (ii) enhance cellular uptake through a myristoylated polyarginine peptide (MPAP) and (iii) selectively induce cell death by ultra-short near infrared laser pulses. We used a biotin-avidin based approach to conjugate EPPT-1 and MPAP to AuNRs. Dual-peptide (EPPT-1+MPAP) labelled AuNRs showed a significantly higher uptake by pancreatic ductal adenocarcinoma cells when compared to their single peptide or avidin conjugated counterparts. In addition, we selectively induced cell death by ultra-short near infrared laser pulses in small target volumes (∼1 μm3), through the creation of plasmonic nanobubbles that lead to the destruction of a local cell environment. Our approach opens new avenues for conjugation of multiple ligands on AuNRs targeting cancer cells and tumors and it is relevant for plasmonic photothermal therapy.

Microwave pumped high-efficient thermoacoustic tumor therapy with single wall carbon nanotubes.

PubMed

Wen, Liewei; Ding, Wenzheng; Yang, Sihua; Xing, Da

2016-01-01

The ultra-short pulse microwave could excite to the strong thermoacoustic (TA) shock wave and deeply penetrate in the biological tissues. Based on this, we developed a novel deep-seated tumor therapy modality with mitochondria-targeting single wall carbon nanotubes (SWNTs) as microwave absorbing agents, which act efficiently to convert ultra-short microwave energy into TA shock wave and selectively destroy the targeted mitochondria, thereby inducing apoptosis in cancer cells. After the treatment of SWNTs (40 μg/mL) and ultra-short microwave (40 Hz, 1 min), 77.5% of cancer cells were killed and the vast majority were caused by apoptosis that initiates from mitochondrial damage. The orthotopic liver cancer mice were established as deep-seated tumor model to investigate the anti-tumor effect of mitochondria-targeting TA therapy. The results suggested that TA therapy could effectively inhibit the tumor growth without any observable side effects, while it was difficult to achieve with photothermal or photoacoustic therapy. These discoveries implied the potential application of TA therapy in deep-seated tumor models and should be further tested for development into a promising therapeutic modality for cancer treatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

Development of a Flow Injection Based High Frequency Dual Channel Quartz Crystal Microbalance

PubMed Central

Liang, Jinxing; Zhang, Jing; Zhou, Wenxiang; Ueda, Toshitsugu

2017-01-01

When the quartz crystal microbalance (QCM) is used in liquid for adsorption or desorption monitoring based bio- or chemical sensing applications, the frequency shift is not only determined by the surface mass change, but also by the change of liquid characteristics, such as density and viscosity, which are greatly affected by the liquid environmental temperature. A monolithic dual-channel QCM is designed and fabricated by arranging two QCM resonators on one single chip for cancelling the fluctuation induced by environmental factors. In actual applications, one QCM works as a specific sensor by modifying with functional membranes and the other acts as a reference, only measuring the liquid property. The dual-channel QCM is designed with an inverted-mesa structure, aiming to realize a high frequency miniaturized chip and suppress the frequency interference between the neighbored QCM resonators. The key problem of dual-channel QCMs is the interference between two channels, which is influenced by the distance of adjacent resonators. The diameter of the reference electrode has been designed into several values in order to find the optimal parameter. Experimental results demonstrated that the two QCMs could vibrate individually and the output frequency stability and drift can be greatly improved with the aid of the reference QCM. PMID:28509851

Microembossing of ultrafine grained Al: microstructural analysis and finite element modelling

NASA Astrophysics Data System (ADS)

Qiao, Xiao Guang; Bah, Mamadou T.; Zhang, Jiuwen; Gao, Nong; Moktadir, Zakaria; Kraft, Michael; Starink, Marco J.

2010-10-01

Ultra-fine-grained (UFG) Al-1050 processed by equal channel angular pressing and UFG Al-Mg-Cu-Mn processed by high-pressure torsion (HPT) were embossed at both room temperature and 300 °C, with the aim of producing micro-channels. The behaviour of Al alloys during the embossing process was analysed using finite element modelling. The cold embossing of both Al alloys is characterized by a partial pattern transfer, a large embossing force, channels with oblique sidewalls and a large failure rate of the mould. The hot embossing is characterized by straight channel sidewalls, fully transferred patterns and reduced loads which decrease the failure rate of the mould. Hot embossing of UFG Al-Mg-Cu-Mn produced by HPT shows a potential of fabrication of microelectromechanical system components with micro channels.

An ultra-dense SNP linkage map for the octoploid, cultivated strawberry and its application in genetic research

USDA-ARS?s Scientific Manuscript database

We will present an ultra-dense genetic linkage map for the octoploid, cultivated strawberry (Fragaria x ananassa) consisting of over 13K Axiom® based SNP markers and 150 previously mapped reference SSR loci. The high quality of the map is demonstrated by the short sizes of each of the 28 linkage gro...

A Resonant Tunneling Nanowire Field Effect Transistor with Physical Contractions: A Negative Differential Resistance Device for Low Power Very Large Scale Integration Applications

NASA Astrophysics Data System (ADS)

Molaei Imen Abadi, Rouzbeh; Saremi, Mehdi

2018-02-01

In this paper, the influence of ultra-scaled physical symmetrical contraction on electrical characteristics of ultra-thin silicon-on-insulator nanowires with circular gate-all-around structure is investigated by using a 3D Atlas numerical quantum simulator based on non-equilibrium green's function formalism. It is demonstrated that local cross-section variation in a nanowire transistor results in the establishment of tunnel energy barriers at the source-channel and drain-channel junctions which change device physics and cause a transmission from a quantum wire (1-D) to a floating quantum dot nanowire (0-D) introducing a resonant tunneling nanowire FET (RT-NWFET) as an interesting concept of nanoscale MOSFETs. The barriers construct resonance energy levels in the channel region of nanowires because of the longitudinal confinement in three directions causing some fluctuation in I D- V GS characteristic. In addition, these barriers remarkably improve the subthreshold swing and minimize the ON/OFF-current ratio degradation at a low operation voltage of 0.5 V. As a result, RT-NWFETs are intrinsically preserved from drain-source tunneling and are an interesting candidate for developing the roadmap below 10 nm.

Ultra-sensitive chemical and biological analysis via specialty fibers with built-in microstructured optofluidic channels.

PubMed

Zhang, Nan; Li, Kaiwei; Cui, Ying; Wu, Zhifang; Shum, Perry Ping; Auguste, Jean-Louis; Dinh, Xuan Quyen; Humbert, Georges; Wei, Lei

2018-02-13

All-in-fiber optofluidics is an analytical tool that provides enhanced sensing performance with simplified analyzing system design. Currently, its advance is limited either by complicated liquid manipulation and light injection configuration or by low sensitivity resulting from inadequate light-matter interaction. In this work, we design and fabricate a side-channel photonic crystal fiber (SC-PCF) and exploit its versatile sensing capabilities in in-line optofluidic configurations. The built-in microfluidic channel of the SC-PCF enables strong light-matter interaction and easy lateral access of liquid samples in these analytical systems. In addition, the sensing performance of the SC-PCF is demonstrated with methylene blue for absorptive molecular detection and with human cardiac troponin T protein by utilizing a Sagnac interferometry configuration for ultra-sensitive and specific biomolecular specimen detection. Owing to the features of great flexibility and compactness, high-sensitivity to the analyte variation, and efficient liquid manipulation/replacement, the demonstrated SC-PCF offers a generic solution to be adapted to various fiber-waveguide sensors to detect a wide range of analytes in real time, especially for applications from environmental monitoring to biological diagnosis.

DEVELOPMENT OF AN AFFINITY SILICA MONOLITH CONTAINING HUMAN SERUM ALBUMIN FOR CHIRAL SEPARATIONS

PubMed Central

Mallik, Rangan; Hage, David S.

2008-01-01

An affinity monolith based on silica and containing immobilized human serum albumin (HSA) was developed and evaluated in terms of its binding, efficiency and selectivity in chiral separations. The results were compared with data obtained for the same protein when used as a chiral stationary phase with HPLC-grade silica particles or a monolith based on a copolymer of glycidyl methacrylate (GMA) and ethylene dimethacrylate (EDMA). The surface coverage of HSA in the silica monolith was similar to values obtained with silica particles and a GMA/EDMA monolith. However, the higher surface area of the silica monolith gave a material that contained 1.3- to 2.2-times more immobilized HSA per unit volume when compared to silica particles or a GMA/EDMA monolith. The retention, efficiency and resolving power of the HSA silica monolith were evaluated using two chiral analytes: D/L-tryptophan and R/S-warfarin. The separation of R- and S-ibuprofen was also considered. The HSA silica monolith gave higher retention and higher or comparable resolution and efficiency when compared with HSA columns that contained silica particles or a GMA/EDMA monolith. The silica monolith also gave lower back pressures and separation impedances than these other materials. It was concluded that silica monoliths can be valuable alternatives to silica particles or GMA/EDMA monoliths when used with immobilized HSA as a chiral stationary phase. PMID:17475436

Quadrilinear CCD sensors for the multispectral channel of spaceborne imagers

NASA Astrophysics Data System (ADS)

Materne, Alex; Gili, Bruno; Laubier, David; Gimenez, Thierry

2001-12-01

The PLEIADES-HR Earth Observation satellites will combine a high resolution panchromatic channel -- 0.7 m at nadir -- and a multispectral channel allowing a 2.8 m resolution. This paper presents the main specifications, design and performances of a 52 microns pitch quadrilinear CCD sensor developed by ATMEL under CNES contract, for the multispectral channel of the PLEIADES-HR instrument. The monolithic CCD device includes four lines of 1500 pixels, each line dedicated to a narrow spectral band within blue to near infra red spectrum. The design of the photodiodes and CCD registers, with larger size than those developed up to now for CNES spaceborne imagers, needed some specific structures to break the large equipotential areas where charge do not flow properly. Results are presented on the options which were experimented to improve sensitivity, maintain transfer efficiency and reduce power dissipation. The four spectral bands are achieved by four stripe filters made by SAGEM-REOSC PRODUCTS on a glass substrate, to be assembled on the sensor window. Line to line spacing on the silicon die takes into account the results of straylight analysis. A mineral layer, with high optical absorption performances is deposited between photosensitive lines to further reduce straylight.

Towards High-Frequency Shape Memory Alloy Actuators Incorporating Liquid Metal Energy Circuits

NASA Astrophysics Data System (ADS)

Hartl, Darren; Mingear, Jacob; Bielefeldt, Brent; Rohmer, John; Zamarripa, Jessica; Elwany, Alaa

2017-12-01

Large shape memory alloy (SMA) actuators are currently limited to applications with low cyclic actuation frequency requirements due to their generally poor heat transfer rates. This limitation can be overcome through the use of distributed body heating methods such as induction heating or by accelerated cooling methods such as forced convection in internal cooling channels. In this work, a monolithic SMA beam actuator containing liquid gallium-indium alloy-filled channels is fabricated through additive manufacturing. These liquid metal channels enable a novel multi-physical thermal control system, allowing for increased heating and cooling rates to facilitate an increased cyclic actuation frequency. Liquid metal flowing in the channels performs the dual tasks of inductively heating the surrounding SMA material and then actively cooling the SMA via forced internal fluid convection. A coupled thermoelectric model, implemented in COMSOL, predicts a possible fivefold increase in the cyclic actuation frequency due to these increased thermal transfer rates when compared to conventional SMA forms having external heating coils and being externally cooled via forced convection. The first ever experimental prototype SMA actuator of this type is described and, even at much lower flow rates, is shown to exhibit a decrease in cooling time of 40.9%.

The Hyperspectral Thermal Emission Spectrometer (HyTES): Preliminary Results

NASA Technical Reports Server (NTRS)

Hook, Simon; Johnson, William R.; Eng, Bjorn T.; Gunapala, Sarah D.; Lamborn, Andrew U.; Mouroulis, Pantazis, Z.; Mouroulis, Pantazis, Z.; Paine, Christopher G.; Soibel, Alexander; Wilson, Daniel W.

2011-01-01

The Hyperspectral Thermal Emission Spectrometer (HyTES) is being developed as part of the risk reduction activities associated with the Hyperspectral Infrared Imager (HyspIRI). HyspIRI is one of the Tier 2 Decadal Survey Missions. HyTES will provide information on how to place the filters on the HyspIRI Thermal Infrared Instrument (TIR) as well as provide antecedent science data. The pushbroom design has 512 spatial pixels over a 50-degree field of view and 256 spectral channels between 7.5 micrometers to 12 micrometers. HyTES includes many key enabling state-of-the-art technologies including a high performance convex diffraction grating, a quantum well infrared photodetector (QWIP) focal plane array, and a compact Dyson-inspired optical design. The Dyson optical design allows for a very compact and optically fast system (F/1.6). It also minimizes cooling requirements due to the fact it has a single monolithic prism-like grating design which allows baffling for stray light suppression. The monolithic configuration eases mechanical tolerancing requirements which are a concern since the complete optical assembly is operated at cryogenic temperatures ((is) approximately 100K). The QWIP allows for optimum spatial and spectral uniformity and provides adequate responsivity or D-star to allow 200mK noise equivalent temperature difference (NEDT) operation across the LWIR passband. Assembly of the system is nearly complete. After completion, alignment results will be presented which show low keystone and smile distortion. This is required to minimize spatial-spectral mixing between adjacent spectral channels and spatial positions. Predictions show the system will have adequate signal to noise for laboratory calibration targets.

Graphene nanoribbon field-effect transistors fabricated by etchant-free transfer from Au(788)

NASA Astrophysics Data System (ADS)

Ohtomo, Manabu; Sekine, Yoshiaki; Hibino, Hiroki; Yamamoto, Hideki

2018-01-01

We report etching-free and iodine-free transfer of highly aligned array of armchair-edge graphene nanoribbons (ACGNRs) and their field-effect transistor (FET) characteristics. They were prepared by on-surface polymerization on Au(788) templates. The ACGNRs were mechanically delaminated and transferred onto insulating substrates with the aid of a nano-porous support layer composed of hydrogen silsesquioxane (HSQ). The key process in the mechanical delamination is the intercalation of octanethiol self-assembled monolayers (SAMs), which penetrate the HSQ layer and intercalate between the ACGNRs and Au(788). After the transfer, the octanethiol SAMs were removed with Piranha solution, enabling the reuse of the Au single crystals. The FETs fabricated with the transferred ACGNR array showed ambipolar behavior when the channel length was as long as 60 nm. Quasi-one-dimensional conductivity was observed, which implies a good alignment of GNRs after the transfer. In contrast, short-channel ACGNR FETs (channel length ˜20 nm) suffer from a geometry-dependent short-channel effect. This effect is more severe in the FETs with ACGNRs parallel to the channel, which is an ideal geometry, than in ones perpendicular to the channel. Since the ID-VD curve is well fitted by the power-law model, the short-channel effect likely stems from the space-charge limited current effect, while the wide charge-transfer region in the GNR channel can be another possible cause for the short-channel effect. These results provide us with important insights into the designing short-channel GNR-FETs with improved performance.

Approaches for springback reduction when forming ultra high-strength sheet metals

NASA Astrophysics Data System (ADS)

Radonjic, R.; Liewald, M.

2016-11-01

Nowadays, the automotive industry is challenged constantly by increasing environmental regulations and the continuous enhancement of standards with regard to passenger's safety (NCAP, Part 1). In order to fulfil the aforementioned requirements, the use of ultra high-strength steels in research and industrial applications is of high interest. When forming such materials, the main problem results from the large amount of springback which occurs after the release of the part. This paper shows the applicability of several approaches for the reduction of springback amount by forming of one hat channel shaped component. A novel approach for springack reduction which is based on forming with an alternating blank draw-in is presented as well. In this investigation an ultra high-strength steel of the grade DP 980 was used. The part's measurements were taken at significant cross-sections in order to provide a qualitative comparison between the reference geometry and the part's released shape. The obtained results were analysed and used in order to quantify the success of particular approaches for springback reduction. When taking a curved hat channel shaped component as an example, the results achieved in the investigations showed that it is possible to reduce part shape deviations significantly when using DP 980 as workpiece material.

Detection of mental stress due to oral academic examination via ultra-short-term HRV analysis.

PubMed

Castaldo, R; Xu, W; Melillo, P; Pecchia, L; Santamaria, L; James, C

2016-08-01

Mental stress may cause cognitive dysfunctions, cardiovascular disorders and depression. Mental stress detection via short-term Heart Rate Variability (HRV) analysis has been widely explored in the last years, while ultra-short term (less than 5 minutes) HRV has been not. This study aims to detect mental stress using linear and non-linear HRV features extracted from 3 minutes ECG excerpts recorded from 42 university students, during oral examination (stress) and at rest after a vacation. HRV features were then extracted and analyzed according to the literature using validated software tools. Statistical and data mining analysis were then performed on the extracted HRV features. The best performing machine learning method was the C4.5 tree algorithm, which discriminated between stress and rest with sensitivity, specificity and accuracy rate of 78%, 80% and 79% respectively.

Picosecond and femtosecond lasers for industrial material processing

NASA Astrophysics Data System (ADS)

Mayerhofer, R.; Serbin, J.; Deeg, F. W.

2016-03-01

Cold laser materials processing using ultra short pulsed lasers has become one of the most promising new technologies for high-precision cutting, ablation, drilling and marking of almost all types of material, without causing unwanted thermal damage to the part. These characteristics have opened up new application areas and materials for laser processing, allowing previously impossible features to be created and also reducing the amount of post-processing required to an absolute minimum, saving time and cost. However, short pulse widths are only one part of thee story for industrial manufacturing processes which focus on total costs and maximum productivity and production yield. Like every other production tool, ultra-short pulse lasers have too provide high quality results with maximum reliability. Robustness and global on-site support are vital factors, as well ass easy system integration.

The enigmatic ultra-long run-out of seafloor density driven flows

NASA Astrophysics Data System (ADS)

Dorrell, R. M.

2017-12-01

Dilute, particulate-laden, density-driven flows - turbidity currents - are a predominant mechanism for transporting sediment from source to sink in deep marine environments. These flows sculpt channels on the seafloor and, as evidenced by a wealth of bathymetric data, can travel for >1000km, forming some of the largest sedimentary landforms on the planet. For turbidity currents to travel such large dsitances, sediment must be self-maintained in suspension, i.e., be in a state of autosuspension. It has been shown that such self-maintained sediment suspensions can only occur whilst inertial forces are greater than gravitational forces, entailing supercritical flow. This conclusion is paradoxical, as inertia dominated flows rapidly entrain fluid, thereby thickening and slowing to become subcritical. However, current theory can only truly be applied to the proximal upper slope regions of seafloor channels where incised flows are fully confined. This contrasts with the distal reaches of long run out turbidity current systems, where the flow is only partially confined through self-channelization. Here it is shown that overspill of partially confined flow has a significant effect on the hydro- and morphodynamics of turbidity current systems. A new model is derived that shows that channel overspill acts to negate the effects of ambient fluid entrainment: a dynamic balance that limits increases in flow depth and maintains supercritical flow throughout the channel. In the new model mass, momentum and energy conservation is modulated by flow overspill onto channel banks, necessarily requiring description of the vertical structure of the flow. Analysis of continuously stratified steady state flow dynamics shows that the integration of overspill and stratification is necessary to enable maintained autosuspension and thus predict the ultra-long run-out of turbidity currents.

Optical and optomechanical ultralightweight C/SiC components

NASA Astrophysics Data System (ADS)

Papenburg, Ulrich; Pfrang, Wilhelm; Kutter, G. S.; Mueller, Claus E.; Kunkel, Bernd P.; Deyerler, Michael; Bauereisen, Stefan

1999-11-01

Optical and optomechanical structures based on silicon carbide (SiC) ceramics are becoming increasingly important for ultra- lightweight optical systems that must work in adverse environments. At IABG and Dornier Satellite Systems (DSS) in Munich, a special form of SiC ceramics carbon fiber reinforced silicon carbide (C/SiCR) has been developed partly under ESA and NASA contracts. C/SiCR is a light-weight, high- strength engineering material that features tunable mechanical and thermal properties. It offers exceptional design freedom due to its reduced brittleness and negligible volume shrinkage during processing in comparison to traditional, powder-based ceramics. Furthermore, its rapid fabrication process produces near-net-shape components using conventional NC machining/milling equipment and, thus, provides substantial schedule, cost, and risk savings. These characteristics allow C/SiCR to overcome many of the problems associated with more traditional optical materials. To date, C/SiCR has been used to produce ultra-lightweight mirrors and reflectors, antennas, optical benches, and monolithic and integrated reference structures for a variety of space and terrestrial applications. This paper describes the material properties, optical system and structural design aspects, the forming and manufacturing process including high-temperature joining technology, precision grinding and cladding techniques, and the performance results of a number of C/SiCR optical components we have built.

Ultra Small Aperture Terminal for Ka-Band SATCOM

NASA Technical Reports Server (NTRS)

Acosta, Roberto; Reinhart, Richard; Lee, Richard; Simons, Rainee

1997-01-01

An ultra small aperture terminal (USAT) at Ka-band frequency has been developed by Lewis Research Center (LeRC) for data rates up to 1.5 Mbps in the transmit mode and 40 Mbps in receive mode. The terminal consists of a 35 cm diameter offset-fed parabolic antenna which is attached to a solid state power amplifier and low noise amplifier. A single down converter is used to convert the Ka-band frequency to 70 MHz intermediate frequency (IF). A variable rate (9.6 Kbps to 10 Mbps) commercial modem with a standard RS-449/RS-232 interface is used to provide point-to-point digital services. The terminal has been demonstrated numerous times using the Advanced Communications Technology Satellite (ACTS) and the 4.5 in Link Evaluation Terminal (LET) in Cleveland. A conceptual design for an advanced terminal has also been developed. This advanced USAT utilizes Microwave Monolithic Integrated Circuit (MMIC) and flat plate array technologies. This terminal will be self contained in a single package which will include a 1 watt solid state amplifier (SSPA), low noise amplifier (LNA) and a modem card located behind the aperture of the array. The advanced USAT will be light weight, transportable, low cost and easy to point to the satellite. This paper will introduce designs for the reflector based and array based USAT's.

Ultra-high density aligned Carbon-nanotube with controled nano-morphology for supercapacitors

NASA Astrophysics Data System (ADS)

Ghaffari, Mehdi; Zhao, Ran; Liu, Yang; Zhou, Yue; Cheng, Jiping; Guzman de Villoria, Roberto; Wardle, B. L.; Zhang, Q. M.

2012-02-01

Recent advances in fabricating controlled-morphology vertically aligned carbon nanotubes (VA-CNTs) with ultrahigh volume fractioncreate unique opportunities for developing unconventional supercapacitors with ultra-high energy density, power density, and long charge/discharge cycle life.Continuous paths through inter-VA-CNT channels allow fast ion transport, and high electrical conduction of the aligned CNTs in the composite electrodes lead to fast discharge speed. We investigate the charge-discharge characteristics of VA-CNTs with >20 vol% of CNT and ionic liquids as electrolytes. By employing both the electric and electromechanical spectroscopes, as well as nanostructured materials characterization, the ion transport and storage behaviors in porous electrodes are studied. The results suggest pathways for optimizing the electrode morphology in supercapacitorsusing ultra-high volume fraction VA-CNTs to further enhance performance.

Magnetic-field sensing coil embedded in ceramic for measuring ambient magnetic field

DOEpatents

Takahashi, Hironori

2004-02-10

A magnetic pick-up coil for measuring magnetic field with high specific sensitivity, optionally with an electrostatic shield (24), having coupling elements (22) with high winding packing ratio, oriented in multiple directions, and embedded in ceramic material for structural support and electrical insulation. Elements of the coil are constructed from green ceramic sheets (200) and metallic ink deposited on surfaces and in via holes of the ceramic sheets. The ceramic sheets and the metallic ink are co-fired to create a monolithic hard ceramic body (20) with metallized traces embedded in, and placed on exterior surfaces of, the hard ceramic body. The compact and rugged coil can be used in a variety of environments, including hostile conditions involving ultra-high vacuum, high temperatures, nuclear and optical radiation, chemical reactions, and physically demanding surroundings, occurring either individually or in combinations.

High-performance terahertz wave absorbers made of silicon-based metamaterials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yin, Sheng; Zhu, Jianfei; Jiang, Wei

2015-08-17

Electromagnetic (EM) wave absorbers with high efficiency in different frequency bands have been extensively investigated for various applications. In this paper, we propose an ultra-broadband and polarization-insensitive terahertz metamaterial absorber based on a patterned lossy silicon substrate. Experimentally, a large absorption efficiency more than 95% in a frequency range of 0.9–2.5 THz was obtained up to a wave incident angle as large as 70°. Much broader absorption bandwidth and excellent oblique incidence absorption performance are numerically demonstrated. The underlying mechanisms due to the combination of a waveguide cavity mode and impedance-matched diffraction are analyzed in terms of the field patternsmore » and the scattering features. The monolithic THz absorber proposed here may find important applications in EM energy harvesting systems such as THz barometer or biosensor.« less

640-Gbit/s fast physical random number generation using a broadband chaotic semiconductor laser

NASA Astrophysics Data System (ADS)

Zhang, Limeng; Pan, Biwei; Chen, Guangcan; Guo, Lu; Lu, Dan; Zhao, Lingjuan; Wang, Wei

2017-04-01

An ultra-fast physical random number generator is demonstrated utilizing a photonic integrated device based broadband chaotic source with a simple post data processing method. The compact chaotic source is implemented by using a monolithic integrated dual-mode amplified feedback laser (AFL) with self-injection, where a robust chaotic signal with RF frequency coverage of above 50 GHz and flatness of ±3.6 dB is generated. By using 4-least significant bits (LSBs) retaining from the 8-bit digitization of the chaotic waveform, random sequences with a bit-rate up to 640 Gbit/s (160 GS/s × 4 bits) are realized. The generated random bits have passed each of the fifteen NIST statistics tests (NIST SP800-22), indicating its randomness for practical applications.

Simulation study of short-channel effects of tunnel field-effect transistors

NASA Astrophysics Data System (ADS)

Fukuda, Koichi; Asai, Hidehiro; Hattori, Junichi; Mori, Takahiro; Morita, Yukinori; Mizubayashi, Wataru; Masahara, Meishoku; Migita, Shinji; Ota, Hiroyuki; Endo, Kazuhiro; Matsukawa, Takashi

2018-04-01

Short-channel effects of tunnel field-effect transistors (FETs) are investigated in detail using simulations of a nonlocal band-to-band tunneling model. Discussion is limited to silicon. Several simulation scenarios were considered to address different effects, such as source overlap and drain offset effects. Adopting the drain offset to suppress the drain leakage current suppressed the short channel effects. The physical mechanism underlying the short-channel behavior of the tunnel FETs (TFETs) was very different from that of metal-oxide-semiconductor FETs (MOSFETs). The minimal gate lengths that do not lose on-state current by one order are shown to be 3 nm for single-gate structures and 2 nm for double gate structures, as determined from the drain offset structure.

Evaluation of microfluidic channels with optical coherence tomography

NASA Astrophysics Data System (ADS)

Czajkowski, J.; Prykäri, T.; Alarousu, E.; Lauri, J.; Myllylä, R.

2010-11-01

Application of time domain, ultra high resolution optical coherence tomography (UHR-OCT) in evaluation of microfluidic channels is demonstrated. Presented study was done using experimental UHR-OCT device based on a Kerr-lens mode locked Ti:sapphire femtosecond laser, a photonic crystal fibre and modified, free-space Michelson interferometer. To show potential of the technique, microfluidic chip fabricated by VTT Center for Printed Intelligence (Oulu, Finland) was measured. Ability for full volumetric reconstruction in non-contact manner enabled complete characterization of closed entity of a microfluidic channel without contamination and harm for the sample. Measurement, occurring problems, and methods of postprocessing for raw data are described. Results present completely resolved physical structure of the channel, its spatial dimensions, draft angles and evaluation of lamination quality.

Adaptive suppression of power line interference in ultra-low field magnetic resonance imaging in an unshielded environment.

PubMed

Huang, Xiaolei; Dong, Hui; Qiu, Yang; Li, Bo; Tao, Quan; Zhang, Yi; Krause, Hans-Joachim; Offenhäusser, Andreas; Xie, Xiaoming

2018-01-01

Power-line harmonic interference and fixed-frequency noise peaks may cause stripe-artifacts in ultra-low field (ULF) magnetic resonance imaging (MRI) in an unshielded environment and in a conductively shielded room. In this paper we describe an adaptive suppression method to eliminate these artifacts in MRI images. This technique utilizes spatial correlation of the interference from different positions, and is realized by subtracting the outputs of the reference channel(s) from those of the signal channel(s) using wavelet analysis and the least squares method. The adaptive suppression method is first implemented to remove the image artifacts in simulation. We then experimentally demonstrate the feasibility of this technique by adding three orthogonal superconducting quantum interference device (SQUID) magnetometers as reference channels to compensate the output of one 2nd-order gradiometer. The experimental results show great improvement in the imaging quality in both 1D and 2D MRI images at two common imaging frequencies, 1.3 kHz and 4.8 kHz. At both frequencies, the effective compensation bandwidth is as high as 2 kHz. Furthermore, we examine the longitudinal relaxation times of the same sample before and after compensation, and show that the MRI properties of the sample did not change after applying adaptive suppression. This technique can effectively increase the imaging bandwidth and be applied to ULF MRI detected by either SQUIDs or Faraday coil in both an unshielded environment and a conductively shielded room. Copyright © 2017 Elsevier Inc. All rights reserved.

High-speed microwave photonic switch for millimeter-wave ultra-wideband signal generation.

PubMed

Wang, Li Xian; Li, Wei; Zheng, Jian Yu; Wang, Hui; Liu, Jian Guo; Zhu, Ning Hua

2013-02-15

We propose a scheme for generating millimeter-wave (MMW) ultra-wideband (UWB) signal that is free from low-frequency components and a residual local oscillator. The system consists of two cascaded polarization modulators and is equivalent to a high-speed microwave photonic switch, which truncates a sinusoidal MMW into short pulses. The polarity switchability of the generated MMW-UWB pulse is also demonstrated.

Manganese oxide micro-supercapacitors with ultra-high areal capacitance

NASA Astrophysics Data System (ADS)

Wang, Xu; Myers, Benjamin D.; Yan, Jian; Shekhawat, Gajendra; Dravid, Vinayak; Lee, Pooi See

2013-05-01

A symmetric micro-supercapacitor is constructed by electrochemically depositing manganese oxide onto micro-patterned current collectors. High surface-to-volume ratio of manganese oxide and short diffusion distance between electrodes give an ultra-high areal capacitance of 56.3 mF cm-2 at a current density of 27.2 μA cm-2.A symmetric micro-supercapacitor is constructed by electrochemically depositing manganese oxide onto micro-patterned current collectors. High surface-to-volume ratio of manganese oxide and short diffusion distance between electrodes give an ultra-high areal capacitance of 56.3 mF cm-2 at a current density of 27.2 μA cm-2. Electronic supplementary information (ESI) available: Experimental procedures; optical images of micro-supercapacitors; areal capacitances of samples M-0.3C, M-0.6C and M-0.9C; illustration of interdigital finger electrodes; Nyquist plot of Co(OH)2 deposited on micro-electrodes. See DOI: 10.1039/c3nr00210a

Plasmonic excitation-assisted optical and electric enhancement in ultra-thin solar cells: the influence of nano-strip cross section

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sabaeian, Mohammad, E-mail: sabaiean@scu.ac.ir; Heydari, Mehdi; Ajamgard, Narges

The effects of Ag nano-strips with triangle, rectangular and trapezoid cross sections on the optical absorption, generation rate, and short-circuit current density of ultra-thin solar cells were investigated. By putting the nano-strips as a grating structure on the top of the solar cells, the waveguide, surface plasmon polariton (SPP), and localized surface plasmon (LSP) modes, which are excited with the assistance of nano-strips, were evaluated in TE and TM polarizations. The results show, firstly, the TM modes are more influential than TE modes in optical and electrical properties enhancement of solar cell, because of plasmonic excitations in TM mode. Secondly,more » the trapezoid nano-strips reveal noticeable impact on the optical absorption, generation rate, and short-circuit current density enhancement than triangle and rectangular ones. In particular, the absorption of long wavelengths which is a challenge in ultra-thin solar cells is significantly improved by using Ag trapezoid nano-strips.« less

A poly(vinyl alcohol)/sodium alginate blend monolith with nanoscale porous structure

PubMed Central

2013-01-01

A stimuli-responsive poly(vinyl alcohol) (PVA)/sodium alginate (SA) blend monolith with nanoscale porous (mesoporous) structure is successfully fabricated by thermally impacted non-solvent induced phase separation (TINIPS) method. The PVA/SA blend monolith with different SA contents is conveniently fabricated in an aqueous methanol without any templates. The solvent suitable for the fabrication of the present blend monolith by TINIPS is different with that of the PVA monolith. The nanostructural control of the blend monolith is readily achieved by optimizing the fabrication conditions. Brunauer Emmett Teller measurement shows that the obtained blend monolith has a large surface area. Pore size distribution plot for the blend monolith obtained by the non-local density functional theory method reveals the existence of the nanoscale porous structure. Fourier transform infrared analysis reveals the strong interactions between PVA and SA. The pH-responsive property of the blend monolith is investigated on the basis of swelling ratio in different pH solutions. The present blend monolith of biocompatible and biodegradable PVA and SA with nanoscale porous structure has large potential for applications in biomedical and environmental fields. PMID:24093494

A poly(vinyl alcohol)/sodium alginate blend monolith with nanoscale porous structure.

PubMed

Sun, Xiaoxia; Uyama, Hiroshi

2013-10-04

A stimuli-responsive poly(vinyl alcohol) (PVA)/sodium alginate (SA) blend monolith with nanoscale porous (mesoporous) structure is successfully fabricated by thermally impacted non-solvent induced phase separation (TINIPS) method. The PVA/SA blend monolith with different SA contents is conveniently fabricated in an aqueous methanol without any templates. The solvent suitable for the fabrication of the present blend monolith by TINIPS is different with that of the PVA monolith. The nanostructural control of the blend monolith is readily achieved by optimizing the fabrication conditions. Brunauer Emmett Teller measurement shows that the obtained blend monolith has a large surface area. Pore size distribution plot for the blend monolith obtained by the non-local density functional theory method reveals the existence of the nanoscale porous structure. Fourier transform infrared analysis reveals the strong interactions between PVA and SA. The pH-responsive property of the blend monolith is investigated on the basis of swelling ratio in different pH solutions. The present blend monolith of biocompatible and biodegradable PVA and SA with nanoscale porous structure has large potential for applications in biomedical and environmental fields.

Investigation of ultra wideband multi-channel dichroic beamsplitters from 0.3 to 52 microns

NASA Technical Reports Server (NTRS)

Zhang, K. Q.; Hunneman, R.; Seeley, J. S.; Hawkins, G. J.

1990-01-01

The development of a set of multi-channel dichroics which includes a 6 channel dichroic operating over the wavelength region from 0.3 to 52 microns is described. In order to achieve the optimum performance, the optical constraints of PbTe, Ge, and CdTe coatings in the strongly absorptive region have been determined by use of a new iterative method using normal incidence reflectance measurement of the multilayer together with initial values of energy gap and infinite refractive index for the semiconductor model. The design and manufacture of the dichroics is discussed and the final results are presented.

Ultra-compact channel drop filter based on photonic crystal nanobeam cavities utilizing a resonant tunneling effect.

PubMed

Ge, Xiaochen; Shi, Yaocheng; He, Sailing

2014-12-15

The design, fabrication, and characterization of a compact photonic crystal nanobeam drop filter based on the tunneling effect of the degenerate modes are presented. The degeneracy was achieved by tuning the coupling distance between the nanobeam and input/output waveguides. The tunneling effect of degenerate resonances with different symmetries has been verified experimentally. Channel drop filters with an extinction ratio larger than 10 dB and a quality factor of ∼5000 have been experimentally demonstrated.

Facile fabrication of mesoporous poly(ethylene-co-vinyl alcohol)/chitosan blend monoliths.

PubMed

Wang, Guowei; Xin, Yuanrong; Uyama, Hiroshi

2015-11-05

Poly(ethylene-co-vinyl alcohol) (EVOH)/chitosan blend monoliths were fabricated by thermally-induced phase separation method. Chitosan was successfully incorporated into the polymeric monolith by selecting EVOH as the main component of the monolith. SEM images exhibit that the chitosan was located on the inner surface of the monolith. Fourier-transform infrared analysis and elemental analysis indicate the successful blend of EVOH and chitosan. BET results show that the blend monoliths had high specific surface area and uniform mesopore structure. Good adsorption ability toward various heavy metal ions was found in the blend monoliths due to the large chelation capacity of chitosan. The blend monoliths have potential application for waste water purification or bio-related applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

Design and performance of an ultra-wideband stepped-frequency radar with precise frequency control for landmine and IED detection

NASA Astrophysics Data System (ADS)

Phelan, Brian R.; Sherbondy, Kelly D.; Ranney, Kenneth I.; Narayanan, Ram M.

2014-05-01

The Army Research Laboratory (ARL) has developed an impulse-based vehicle-mounted forward-looking ultra- wideband (UWB) radar for imaging buried landmines and improvised explosive devices (IEDs). However, there is no control of the radiated spectrum in this system. As part of ARL's Partnerships in Research Transition (PIRT) program, the above deficiency is addressed by the design of a Stepped-Frequency Radar (SFR) which allows for precise control over the radiated spectrum, while still maintaining an effective ultra-wide bandwidth. The SFR utilizes a frequency synthesizer which can be configured to excise prohibited and interfering frequency bands and also implement frequency-hopping capabilities. The SFR is designed to be a forward-looking ground- penetrating (FLGPR) Radar utilizing a uniform linear array of sixteen (16) Vivaldi notch receive antennas and two (2) Quad-ridge horn transmit antennas. While a preliminary SFR consisting of four (4) receive channels has been designed, this paper describes major improvements to the system, and an analysis of expected system performance. The 4-channel system will be used to validate the SFR design which will eventually be augmented in to the full 16-channel system. The SFR has an operating frequency band which ranges from 300 - 2000 MHz, and a minimum frequency step-size of 1 MHz. The radar system is capable of illuminating range swaths that have maximum extents of 30 to 150 meters (programmable). The transmitter has the ability to produce approximately -2 dBm/MHz average power over the entire operating frequency range. The SFR will be used to determine the practicality of detecting and classifying buried and concealed landmines and IEDs from safe stand-off distances.

ZAP! The X-Ray Laser is Born

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ratner, Daniel

2009-11-17

SLAC has converted its giant particle accelerator into the world's first X-ray laser. By a billion fold the world's brightest X-ray source, the laser packs a trillion photons into pulses as short as a millionth of a billionth of a second. The ultra-bright, ultra-short X-ray pulses will drive a wide range of new experiments, as scientists strip electrons from atoms, photograph single molecules and make movies of chemical reactions. How has SLAC accomplished such feats of X-ray wizardry? Attend this public lecture to learn about the basics of an X-ray laser, the technologies at SLAC that make it possible, andmore » the exciting new experiments now underway.« less

X-ray absorption of a warm dense aluminum plasma created by an ultra-short laser pulse

NASA Astrophysics Data System (ADS)

Lecherbourg, L.; Renaudin, P.; Bastiani-Ceccotti, S.; Geindre, J.-P.; Blancard, C.; Cossé, P.; Faussurier, G.; Shepherd, R.; Audebert, P.

2007-05-01

Point-projection K-shell absorption spectroscopy has been used to measure absorption spectra of transient aluminum plasma created by an ultra-short laser pulse. The 1s-2p and 1s-3p absorption lines of weakly ionized aluminum were measured for an extended range of densities in a low-temperature regime. Independent plasma characterization was obtained using frequency domain interferometry diagnostic (FDI) that allows the interpretation of the absorption spectra in terms of spectral opacities. A detailed opacity code using the density and temperature inferred from the FDI reproduce the measured absorption spectra except in the last stage of the recombination phase.

Interrogation of weak Bragg grating sensors based on dual-wavelength differential detection.

PubMed

Cheng, Rui; Xia, Li

2016-11-15

It is shown that for weak Bragg gratings the logarithmic ratio of reflected intensities at any two wavelengths within the spectrum follows a linear relationship with the Bragg wavelength shift, with a slope proportional to their wavelength spacing. This finding is exploited to develop a flexible, efficient, and cheap interrogation solution of weak fiber Bragg grating (FBGs), especially ultra-short FBGs, in distributed sensing based on dual-wavelength differential detection. The concept is experimentally studied in both single and distributed sensing systems with ultra-short FBG sensors. The work may form the basis of new and promising FBG interrogation techniques based on detecting discrete rather than continuous spectra.

Start-to-end simulation of single-particle imaging using ultra-short pulses at the European X-ray Free-Electron Laser

PubMed Central

Buzmakov, Alexey; Jurek, Zoltan; Loh, Ne-Te Duane; Samoylova, Liubov; Santra, Robin; Schneidmiller, Evgeny A.; Tschentscher, Thomas; Yakubov, Sergey; Yoon, Chun Hong; Yurkov, Michael V.; Ziaja-Motyka, Beata; Mancuso, Adrian P.

2017-01-01

Single-particle imaging with X-ray free-electron lasers (XFELs) has the potential to provide structural information at atomic resolution for non-crystalline biomolecules. This potential exists because ultra-short intense pulses can produce interpretable diffraction data notwithstanding radiation damage. This paper explores the impact of pulse duration on the interpretability of diffraction data using comprehensive and realistic simulations of an imaging experiment at the European X-ray Free-Electron Laser. It is found that the optimal pulse duration for molecules with a few thousand atoms at 5 keV lies between 3 and 9 fs. PMID:28989713

Surface modified aerogel monoliths

NASA Technical Reports Server (NTRS)

Leventis, Nicholas (Inventor); Johnston, James C. (Inventor); Kuczmarski, Maria A. (Inventor); Meador, Mary Ann B. (Inventor)

2013-01-01

This invention comprises reinforced aerogel monoliths such as silica aerogels having a polymer coating on its outer geometric surface boundary, and to the method of preparing said aerogel monoliths. The polymer coatings on the aerogel monoliths are derived from polymer precursors selected from the group consisting of isocyanates as a precursor, precursors of epoxies, and precursors of polyimides. The coated aerogel monoliths can be modified further by encapsulating the aerogel with the polymer precursor reinforced with fibers such as carbon or glass fibers to obtain mechanically reinforced composite encapsulated aerogel monoliths.

Miniaturized Ultrasound Imaging Probes Enabled by CMUT Arrays with Integrated Frontend Electronic Circuits

PubMed Central

Khuri-Yakub, B. (Pierre) T.; Oralkan, Ömer; Nikoozadeh, Amin; Wygant, Ira O.; Zhuang, Steve; Gencel, Mustafa; Choe, Jung Woo; Stephens, Douglas N.; de la Rama, Alan; Chen, Peter; Lin, Feng; Dentinger, Aaron; Wildes, Douglas; Thomenius, Kai; Shivkumar, Kalyanam; Mahajan, Aman; Seo, Chi Hyung; O’Donnell, Matthew; Truong, Uyen; Sahn, David J.

2010-01-01

Capacitive micromachined ultrasonic transducer (CMUT) arrays are conveniently integrated with frontend integrated circuits either monolithically or in a hybrid multichip form. This integration helps with reducing the number of active data processing channels for 2D arrays. This approach also preserves the signal integrity for arrays with small elements. Therefore CMUT arrays integrated with electronic circuits are most suitable to implement miniaturized probes required for many intravascular, intracardiac, and endoscopic applications. This paper presents examples of miniaturized CMUT probes utilizing 1D, 2D, and ring arrays with integrated electronics. PMID:21097106

Quad-channel beam switching WR3-band transmitter MMIC

NASA Astrophysics Data System (ADS)

Müller, Daniel; Eren, Gülesin; Wagner, Sandrine; Tessmann, Axel; Leuther, Arnulf; Zwick, Thomas; Kallfass, Ingmar

2017-05-01

Millimeter wave radar systems offer several advantages such as the combination of high resolution and the penetration of adverse atmosphere like smoke, dust or rain. This paper presents a monolithic millimeter wave integrated circuit (MMIC) transmitter which offers four channel beam steering capabilities and can be used as a radar or communication system transmitter. At the local oscillator input, in order to simplify packaging, a frequency tripler is used to multiply the 76.6 - 83.3 GHz input signal to the intended 230 - 250 GHz output frequency range. A resistive mixer is used for the conversion of the intermediate frequency signal into the RF domain. The actual beam steering network is realized using an active single pole quadruple throw (SP4T) switch, which is connected to a integrated Butler matrix. The MMIC was fabricated in a 35 nm InGaAs mHEMT process and has a size of 4.0 mm × 1.5 mm

Transient Catalytic Combustor Model With Detailed Gas and Surface Chemistry

NASA Technical Reports Server (NTRS)

Struk, Peter M.; Dietrich, Daniel L.; Mellish, Benjamin P.; Miller, Fletcher J.; Tien, James S.

2005-01-01

In this work, we numerically investigate the transient combustion of a premixed gas mixture in a narrow, perfectly-insulated, catalytic channel which can represent an interior channel of a catalytic monolith. The model assumes a quasi-steady gas-phase and a transient, thermally thin solid phase. The gas phase is one-dimensional, but it does account for heat and mass transfer in a direction perpendicular to the flow via appropriate heat and mass transfer coefficients. The model neglects axial conduction in both the gas and in the solid. The model includes both detailed gas-phase reactions and catalytic surface reactions. The reactants modeled so far include lean mixtures of dry CO and CO/H2 mixtures, with pure oxygen as the oxidizer. The results include transient computations of light-off and system response to inlet condition variations. In some cases, the model predicts two different steady-state solutions depending on whether the channel is initially hot or cold. Additionally, the model suggests that the catalytic ignition of CO/O2 mixtures is extremely sensitive to small variations of inlet equivalence ratios and parts per million levels of H2.

Potential Large Decadal Missions Enabled by Nasas Space Launch System

NASA Technical Reports Server (NTRS)

Stahl, H. Philip; Hopkins, Randall C.; Schnell, Andrew; Smith, David Alan; Jackman, Angela; Warfield, Keith R.

2016-01-01

Large space telescope missions have always been limited by their launch vehicle's mass and volume capacities. The Hubble Space Telescope (HST) was specifically designed to fit inside the Space Shuttle and the James Webb Space Telescope (JWST) is specifically designed to fit inside an Ariane 5. Astrophysicists desire even larger space telescopes. NASA's "Enduring Quests Daring Visions" report calls for an 8- to 16-m Large UV-Optical-IR (LUVOIR) Surveyor mission to enable ultra-high-contrast spectroscopy and coronagraphy. AURA's "From Cosmic Birth to Living Earth" report calls for a 12-m class High-Definition Space Telescope to pursue transformational scientific discoveries. NASA's "Planning for the 2020 Decadal Survey" calls for a Habitable Exoplanet Imaging (HabEx) and a LUVOIR as well as Far-IR and an X-Ray Surveyor missions. Packaging larger space telescopes into existing launch vehicles is a significant engineering complexity challenge that drives cost and risk. NASA's planned Space Launch System (SLS), with its 8 or 10-m diameter fairings and ability to deliver 35 to 45-mt of payload to Sun-Earth-Lagrange-2, mitigates this challenge by fundamentally changing the design paradigm for large space telescopes. This paper reviews the mass and volume capacities of the planned SLS, discusses potential implications of these capacities for designing large space telescope missions, and gives three specific mission concept implementation examples: a 4-m monolithic off-axis telescope, an 8-m monolithic on-axis telescope and a 12-m segmented on-axis telescope.

Potential large missions enabled by NASA's space launch system

NASA Astrophysics Data System (ADS)

Stahl, H. Philip; Hopkins, Randall C.; Schnell, Andrew; Smith, David A.; Jackman, Angela; Warfield, Keith R.

2016-07-01

Large space telescope missions have always been limited by their launch vehicle's mass and volume capacities. The Hubble Space Telescope (HST) was specifically designed to fit inside the Space Shuttle and the James Webb Space Telescope (JWST) is specifically designed to fit inside an Ariane 5. Astrophysicists desire even larger space telescopes. NASA's "Enduring Quests Daring Visions" report calls for an 8- to 16-m Large UV-Optical-IR (LUVOIR) Surveyor mission to enable ultra-high-contrast spectroscopy and coronagraphy. AURA's "From Cosmic Birth to Living Earth" report calls for a 12-m class High-Definition Space Telescope to pursue transformational scientific discoveries. NASA's "Planning for the 2020 Decadal Survey" calls for a Habitable Exoplanet Imaging (HabEx) and a LUVOIR as well as Far-IR and an X-Ray Surveyor missions. Packaging larger space telescopes into existing launch vehicles is a significant engineering complexity challenge that drives cost and risk. NASA's planned Space Launch System (SLS), with its 8 or 10-m diameter fairings and ability to deliver 35 to 45-mt of payload to Sun-Earth-Lagrange-2, mitigates this challenge by fundamentally changing the design paradigm for large space telescopes. This paper reviews the mass and volume capacities of the planned SLS, discusses potential implications of these capacities for designing large space telescope missions, and gives three specific mission concept implementation examples: a 4-m monolithic off-axis telescope, an 8-m monolithic on-axis telescope and a 12-m segmented on-axis telescope.

Demonstration of ultra-wideband (UWB) over fiber based on optical pulse-injected semiconductor laser.

PubMed

Juan, Yu-Shan; Lin, Fan-Yi

2010-04-26

We experimentally demonstrated the ultra-wideband (UWB) signal generation utilizing nonlinear dynamics of an optical pulse-injected semiconductor laser. The UWB signals generated are fully in compliant with the FCC mask for indoor radiation, while a large fractional bandwidth of 93% is achieved. To show the feasibility of UWB-over-fiber, transmission over a 2 km single-mode fiber and a wireless channel utilizing a pair of broadband antennas are examined. Moreover, proof of concept experiment on data encoding and decoding with 250 Mb/s in the optical pulse-injected laser is successfully demonstrated.

Photonic generation of ultra-wideband signals by direct current modulation on SOA section of an SOA-integrated SGDBR laser.

PubMed

Lv, Hui; Yu, Yonglin; Shu, Tan; Huang, Dexiu; Jiang, Shan; Barry, Liam P

2010-03-29

Photonic ultra-wideband (UWB) pulses are generated by direct current modulation of a semiconductor optical amplifier (SOA) section of an SOA-integrated sampled grating distributed Bragg reflector (SGDBR) laser. Modulation responses of the SOA section of the laser are first simulated with a microwave equivalent circuit model. Simulated results show a resonance behavior indicating the possibility to generate UWB signals with complex shapes in the time domain. The UWB pulse generation is then experimentally demonstrated for different selected wavelength channels with an SOA-integrated SGDBR laser.

Gravitational Waves From Ultra Short Period Exoplanets

NASA Astrophysics Data System (ADS)

Cunha, J. V.; Silva, F. E.; Lima, J. A. S.

2018-06-01

In the last two decades, thousands of extrasolar planets were discovered based on different observational techniques, and their number must increase substantially in virtue of the ongoing and near-future approved missions and facilities. It is shown that interesting signatures of binary systems from nearby exoplanets and their parent stars can also be obtained measuring the pattern of gravitational waves that will be made available by the new generation of detectors including the space-based LISA (Laser Interferometer Space Antenna) observatory. As an example, a subset of exoplanets with extremely short periods (less than 80 min) is discussed. All of them have gravitational luminosity, LGW ˜ 1030erg/s, strain h ˜ 10-22, frequencies fgw > 10-4Hz, and, as such, are within the standard sensitivity curve of LISA. Our analysis suggests that the emitted gravitational wave pattern may also provide an efficient tool to discover ultra short period exoplanets.

Ultra-wideband WDM VCSEL arrays by lateral heterogeneous integration

NASA Astrophysics Data System (ADS)

Geske, Jon

Advancements in heterogeneous integration are a driving factor in the development of evermore sophisticated and functional electronic and photonic devices. Such advancements will merge the optical and electronic capabilities of different material systems onto a common integrated device platform. This thesis presents a new lateral heterogeneous integration technology called nonplanar wafer bonding. The technique is capable of integrating multiple dissimilar semiconductor device structures on the surface of a substrate in a single wafer bond step, leaving different integrated device structures adjacent to each other on the wafer surface. Material characterization and numerical simulations confirm that the material quality is not compromised during the process. Nonplanar wafer bonding is used to fabricate ultra-wideband wavelength division multiplexed (WDM) vertical-cavity surface-emitting laser (VCSEL) arrays. The optically-pumped VCSEL arrays span 140 nm from 1470 to 1610 nm, a record wavelength span for devices operating in this wavelength range. The array uses eight wavelength channels to span the 140 nm with all channels separated by precisely 20 nm. All channels in the array operate single mode to at least 65°C with output power uniformity of +/- 1 dB. The ultra-wideband WDM VCSEL arrays are a significant first step toward the development of a single-chip source for optical networks based on coarse WDM (CWDM), a low-cost alternative to traditional dense WDM. The CWDM VCSEL arrays make use of fully-oxidized distributed Bragg reflectors (DBRs) to provide the wideband reflectivity required for optical feedback and lasing across 140 rim. In addition, a novel optically-pumped active region design is presented. It is demonstrated, with an analytical model and experimental results, that the new active-region design significantly improves the carrier uniformity in the quantum wells and results in a 50% lasing threshold reduction and a 20°C improvement in the peak operating temperature of the devices. This thesis investigates the integration and fabrication technologies required to fabricate ultra-wideband WDM VCSEL arrays. The complete device design and fabrication process is presented along with actual device results from completed CWDM VCSEL arrays. Future recommendations for improvements are presented, along with a roadmap toward a final electrically-pumped single-chip source for CWDM applications.

Analysing black phosphorus transistors using an analytic Schottky barrier MOSFET model.

PubMed

Penumatcha, Ashish V; Salazar, Ramon B; Appenzeller, Joerg

2015-11-13

Owing to the difficulties associated with substitutional doping of low-dimensional nanomaterials, most field-effect transistors built from carbon nanotubes, two-dimensional crystals and other low-dimensional channels are Schottky barrier MOSFETs (metal-oxide-semiconductor field-effect transistors). The transmission through a Schottky barrier-MOSFET is dominated by the gate-dependent transmission through the Schottky barriers at the metal-to-channel interfaces. This makes the use of conventional transistor models highly inappropriate and has lead researchers in the past frequently to extract incorrect intrinsic properties, for example, mobility, for many novel nanomaterials. Here we propose a simple modelling approach to quantitatively describe the transfer characteristics of Schottky barrier-MOSFETs from ultra-thin body materials accurately in the device off-state. In particular, after validating the model through the analysis of a set of ultra-thin silicon field-effect transistor data, we have successfully applied our approach to extract Schottky barrier heights for electrons and holes in black phosphorus devices for a large range of body thicknesses.

Analysing black phosphorus transistors using an analytic Schottky barrier MOSFET model

PubMed Central

Penumatcha, Ashish V.; Salazar, Ramon B.; Appenzeller, Joerg

2015-01-01

Owing to the difficulties associated with substitutional doping of low-dimensional nanomaterials, most field-effect transistors built from carbon nanotubes, two-dimensional crystals and other low-dimensional channels are Schottky barrier MOSFETs (metal-oxide-semiconductor field-effect transistors). The transmission through a Schottky barrier-MOSFET is dominated by the gate-dependent transmission through the Schottky barriers at the metal-to-channel interfaces. This makes the use of conventional transistor models highly inappropriate and has lead researchers in the past frequently to extract incorrect intrinsic properties, for example, mobility, for many novel nanomaterials. Here we propose a simple modelling approach to quantitatively describe the transfer characteristics of Schottky barrier-MOSFETs from ultra-thin body materials accurately in the device off-state. In particular, after validating the model through the analysis of a set of ultra-thin silicon field-effect transistor data, we have successfully applied our approach to extract Schottky barrier heights for electrons and holes in black phosphorus devices for a large range of body thicknesses. PMID:26563458

Measurement and calculation of ternary oxide mixtures for thin films for ultra short pulse laser optics

NASA Astrophysics Data System (ADS)

Jupé, M.; Mende, M.; Kolleck, C.; Ristau, D.; Gallais, L.; Mangote, B.

2011-12-01

The femto-second technology gains of increasing importance in industrial applications. In this context, a new generation of compact and low cost laser sources has to be provided on a commercial basis. Typical pulse durations of these sources are specified in the range from a few hundred femtoup to some pico-seconds, and typical wavelengths are centered around 1030-1080nm. As a consequence, also the demands imposed on high power optical components for these laser sources are rapidly increasing, especially in respect to their power handling capability in the ultra-short pulse range. The present contribution is dedicated to some aspects for improving this quality parameter of optical coatings. The study is based on a set of hafnia and silica mixtures with different compositions and optical band gaps. This material combination displays under ultra-short pulse laser irradiation effects, which are typically for thermal processes. For instance, melting had been observed in the morphology of damaged sides. In this context, models for a prediction of the laser damage thresholds and scaling laws are scrutinized, and have been modified calculating the energy of the electron ensemble. Furthermore, a simple first order approach for the calculation of the temperature was included.

Metasurface for multi-channel terahertz beam splitters and polarization rotators

NASA Astrophysics Data System (ADS)

Zang, XiaoFei; Gong, HanHong; Li, Zhen; Xie, JingYa; Cheng, QingQing; Chen, Lin; Shkurinov, Alexander P.; Zhu, YiMing; Zhuang, SongLin

2018-04-01

Terahertz beam splitters and polarization rotators are two typical devices with wide applications ranging from terahertz communication to system integration. However, they are faced with severe challenges in manipulating THz waves in multiple channels, which is desirable for system integration and device miniaturization. Here, we propose a method to design ultra-thin multi-channel THz beam splitters and polarization rotators simultaneously. The reflected beams are divided into four beams with nearly the same density under illumination of linear-polarized THz waves, while the polarization of reflected beams in each channel is modulated with a rotation angle or invariable with respect to the incident THz waves, leading to the multi-channel polarization rotator (multiple polarization rotation in the reflective channels) and beam splitter, respectively. Reflective metasurfaces, created by patterning metal-rods with different orientations on a polyimide film, were fabricated and measured to demonstrate these characteristics. The proposed approach provides an efficient way of controlling polarization of THz waves in various channels, which significantly simplifies THz functional devices and the experimental system.

Microfluidic devices and methods including porous polymer monoliths

DOEpatents

Hatch, Anson V; Sommer, Gregory J; Singh, Anup K; Wang, Ying-Chih; Abhyankar, Vinay V

2014-04-22

Microfluidic devices and methods including porous polymer monoliths are described. Polymerization techniques may be used to generate porous polymer monoliths having pores defined by a liquid component of a fluid mixture. The fluid mixture may contain iniferters and the resulting porous polymer monolith may include surfaces terminated with iniferter species. Capture molecules may then be grafted to the monolith pores.

Microfluidic devices and methods including porous polymer monoliths

DOEpatents

Hatch, Anson V.; Sommer, Gregory j.; Singh, Anup K.; Wang, Ying-Chih; Abhyankar, Vinay

2015-12-01

Microfluidic devices and methods including porous polymer monoliths are described. Polymerization techniques may be used to generate porous polymer monoliths having pores defined by a liquid component of a fluid mixture. The fluid mixture may contain iniferters and the resulting porous polymer monolith may include surfaces terminated with iniferter species. Capture molecules may then be grafted to the monolith pores.

III-Nitride Digital Alloy: Electronics and Optoelectronics Properties of the InN/GaN Ultra-Short Period Superlattice Nanostructures.

PubMed

Sun, Wei; Tan, Chee-Keong; Tansu, Nelson

2017-07-27

The III-Nitride digital alloy (DA) is comprehensively studied as a short-period superlattice nanostructure consisting of ultra-thin III-Nitride epitaxial layers. By stacking the ultra-thin III-Nitride epitaxial layers periodically, these nanostructures are expected to have comparable optoelectronic properties as the conventional III-Nitride alloys. Here we carried out numerical studies on the InGaN DA showing the tunable optoelectronic properties of the III-Nitride DA. Our study shows that the energy gap of the InGaN DA can be tuned from ~0.63 eV up to ~2.4 eV, where the thicknesses and the thickness ratio of each GaN and InN ultra-thin binary layers within the DA structure are the key factors for tuning bandgap. Correspondingly, the absorption spectra of the InGaN DA yield broad wavelength tunability which is comparable to that of bulk InGaN ternary alloy. In addition, our investigation also reveals that the electron-hole wavefunction overlaps are remarkably large in the InGaN DA structure despite the existence of strain effect and build-in polarization field. Our findings point out the potential of III-Nitride DA as an artificially engineered nanostructure for optoelectronic device applications.

Interaction dynamics of fs-laser induced cavitation bubbles and their impact on the laser-tissue-interaction of modern ophthalmic laser systems

NASA Astrophysics Data System (ADS)

Tinne, N.; Ripken, T.; Lubatschowski, H.; Heisterkamp, A.

2011-07-01

A today well-known laser based treatment in ophthalmology is the LASIK procedure which nowadays includes cutting of the corneal tissue with ultra-short laser pulses. Instead of disposing a microkeratome for cutting a corneal flap, a focused ultra-short laser pulse is scanned below the surface of biological tissue causing the effect of an optical breakdown and hence obtaining a dissection. Inside the tissue, the energy of the laser pulses is absorbed by non-linear processes; as a result a cavitation bubble expands and ruptures the tissue. Hence, positioning of several optical breakdowns side by side generates an incision. Due to a reduction of the amount of laser energy, with a moderate duration of treatment at the same time, the current development of ultra-short pulse laser systems points to higher repetition rates in the range of even Megahertz instead of tens or hundreds of Kilohertz. In turn, this results in a pulse overlap and therefor a probable occurrence of interaction between different optical breakdowns and respectively cavitation bubbles of adjacent optical breakdowns. While the interaction of one single laser pulse with biological tissue is analyzed reasonably well experimentally and theoretically, the interaction of several spatial and temporal following pulses is scarcely determined yet. Thus, the aim of this study is to analyse the dynamic and interaction of two cavitation bubbles by using high speed photography. The applied laser pulse energy, the energy ratio and the spot distance between different cavitation bubbles were varied. Depending on a change of these parameters different kinds of interactions such as a flattening and deformation of bubble shape or jet formation are observed. The effects will be discussed regarding the medical ophthalmic application of fs-lasers. Based on these results a further research seems to be inevitable to comprehend and optimize the cutting effect of ultra-short pulse laser systems with high (> 500 kHz) repetition rates.

Effect of Load Rate on Ultimate Tensile Strength of Ceramic Matrix Composites at Elevated Temperatures

NASA Technical Reports Server (NTRS)

Choi, Sung R.; Gyekenyesi, John P.

2001-01-01

The strengths of three continuous fiber-reinforced ceramic composites, including SiC/CAS-II, SiC/MAS-5 and SiC/SiC, were determined as a function of test rate in air at 1100 to 1200 C. All three composite materials exhibited a strong dependency of strength on test rate, similar to the behavior observed in many advanced monolithic ceramics at elevated temperatures. The application of the preloading technique as well as the prediction of life from one loading configuration (constant stress-rate) to another (constant stress loading) suggested that the overall macroscopic failure mechanism of the composites would be the one governed by a power-law type of damage evolution/accumulation, analogous to slow crack growth commonly observed in advanced monolithic ceramics. It was further found that constant stress-rate testing could be used as an alternative to life prediction test methodology even for composite materials, at least for short range of lifetimes and when ultimate strength is used as the failure criterion.

Preparation of novel beta-cyclodextrin functionalized monolith and its application in chiral separation.

PubMed

Lv, Yongqin; Mei, Danping; Pan, Xinxin; Tan, Tianwei

2010-09-15

A novel beta-cyclodextrin (beta-CD) functionalized organic polymer monolith was prepared by covalently bonding ethylenediamine-beta-CD (EDA-beta-CD) to poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) (poly(GMA-co-EGDMA)) monolith via ring opening reaction of epoxy groups. SEM characterization was performed to confirm the homogeneity of the monolithic polymer. The resulting monolith was then characterized by DSC and XPS elemental analysis to study the thermal stability of the monolith, and to prove the successful immobilization of beta-CD on the polymer substrate. The beta-CD ligand density of 0.68 mmol g(-1) was obtained for the modified monolith, indicating the high reactivity and efficiency of the EDA-beta-CD modifier. The ethylenediamine-beta-CD functionalized monoliths were used for the chiral separation of ibuprofen racemic mixture and showed promising results. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Linear conduction in N-type organic field effect transistors with nanometric channel lengths and graphene as electrodes

NASA Astrophysics Data System (ADS)

Chianese, F.; Candini, A.; Affronte, M.; Mishra, N.; Coletti, C.; Cassinese, A.

2018-05-01

In this work, we test graphene electrodes in nanometric channel n-type Organic Field Effect Transistors (OFETs) based on thermally evaporated thin films of the perylene-3,4,9,10-tetracarboxylic acid diimide derivative. By a thorough comparison with short channel transistors made with reference gold electrodes, we found that the output characteristics of the graphene-based devices respond linearly to the applied bias, in contrast with the supralinear trend of gold-based transistors. Moreover, short channel effects are considerably suppressed in graphene electrode devices. More specifically, current on/off ratios independent of the channel length (L) and enhanced response for high longitudinal biases are demonstrated for L down to ˜140 nm. These results are rationalized taking into account the morphological and electronic characteristics of graphene, showing that the use of graphene electrodes may help to overcome the problem of Space Charge Limited Current in short channel OFETs.

Mechanically stable, hierarchically porous Cu3(btc)2 (HKUST-1) monoliths via direct conversion of copper(II) hydroxide-based monoliths.

PubMed

Moitra, Nirmalya; Fukumoto, Shotaro; Reboul, Julien; Sumida, Kenji; Zhu, Yang; Nakanishi, Kazuki; Furukawa, Shuhei; Kitagawa, Susumu; Kanamori, Kazuyoshi

2015-02-28

The synthesis of highly crystalline macro-meso-microporous monolithic Cu3(btc)2 (HKUST-1; btc(3-) = benzene-1,3,5-tricarboxylate) is demonstrated by direct conversion of Cu(OH)2-based monoliths while preserving the characteristic macroporous structure. The high mechanical strength of the monoliths is promising for possible applications to continuous flow reactors.

Designing Catalytic Monoliths For Closed-Cycle CO2 Lasers

NASA Technical Reports Server (NTRS)

Guinn, Keith; Herz, Richard K.; Goldblum, Seth; Noskowski, ED

1992-01-01

LASCAT (Design of Catalytic Monoliths for Closed-Cycle Carbon Dioxide Lasers) computer program aids in design of catalyst in monolith by simulating effects of design decisions on performance of laser. Provides opportunity for designer to explore tradeoffs among activity and dimensions of catalyst, dimensions of monolith, pressure drop caused by flow of gas through monolith, conversion of oxygen, and other variables. Written in FORTRAN 77.

Chromatographic assessment of two hybrid monoliths prepared via epoxy-amine ring-opening polymerization and methacrylate-based free radical polymerization using methacrylate epoxy cyclosiloxane as functional monomer.

PubMed

Wang, Hongwei; Ou, Junjie; Lin, Hui; Liu, Zhongshan; Huang, Guang; Dong, Jing; Zou, Hanfa

2014-11-07

Two kinds of hybrid monolithic columns were prepared by using methacrylate epoxy cyclosiloxane (epoxy-MA) as functional monomer, containing three epoxy moieties and one methacrylate group. One column was in situ fabricated by ring-opening polymerization of epoxy-MA and 1,10-diaminodecane (DAD) using a porogenic system consisting of isopropanol (IPA), H2O and ethanol at 65°C for 12h. The other was prepared by free radical polymerization of epoxy-MA and ethylene dimethacrylate (EDMA) using 1-propanol and 1,4-butanediol as the porogenic solvents at 60°C for 12h. Two hybrid monoliths were investigated on the morphology and chromatographic assessment. Although two kinds of monolithic columns were prepared with epoxy-MA, their morphologies looked rather different. It could be found that the epoxy-MA-DAD monolith possessed higher column efficiencies (25,000-34,000plates/m) for the separation of alkylbenzenes than the epoxy-MA-EDMA monolith (12,000-13,000plates/m) in reversed-phase nano-liquid chromatography (nano-LC). Depending on the remaining epoxy or methacrylate groups on the surface of two pristine monoliths, the epoxy-MA-EDMA monolith could be easily modified with 1-octadecylamine (ODA) via ring-opening reaction, while the epoxy-MA-DAD monolith could be modified with stearyl methacrylate (SMA) via free radical reaction. The chromatographic performance for the separation of alkylbenzenes on SMA-modified epoxy-MA-DAD monolith was remarkably improved (42,000-54,000 plates/m) when compared with that on pristine epoxy-MA-DAD monolith, while it was not obviously enhanced on ODA-modified epoxy-MA-EDMA monolith when compared with that on pristine epoxy-MA-EDMA monolith. The enhancement of the column efficiency of epoxy-MA-DAD monolith after modification might be ascribed to the decreased mass-transfer resistence. The two kinds of hybrid monoliths were also applied for separations of six phenols and seven basic compounds in nano-LC. Copyright © 2014 Elsevier B.V. All rights reserved.

GaAs MMIC: recovery from upset by x-ray pulse

DOE Office of Scientific and Technical Information (OSTI.GOV)

Armendariz, M.G.; Castle, J.G. Jr.

1986-01-01

Tolerance for fast neutrons and total ionizing dose is a feature of GaAs microwave monolithic integrated circuits (MMIC). However, upset during an ionizing pulse is expected to occur and delayed recovery due to backgating may be a problem. The purpose of this study of an experimental MMIC design is to observe the recovery of oscillator power output following upset by a short ionizing pulse as a function of applied bias, dose per pulse and case temperature.

Cross-flow electrochemical reactor cells, cross-flow reactors, and use of cross-flow reactors for oxidation reactions

DOEpatents

Balachandran, Uthamalingam; Poeppel, Roger B.; Kleefisch, Mark S.; Kobylinski, Thaddeus P.; Udovich, Carl A.

1994-01-01

This invention discloses cross-flow electrochemical reactor cells containing oxygen permeable materials which have both electron conductivity and oxygen ion conductivity, cross-flow reactors, and electrochemical processes using cross-flow reactor cells having oxygen permeable monolithic cores to control and facilitate transport of oxygen from an oxygen-containing gas stream to oxidation reactions of organic compounds in another gas stream. These cross-flow electrochemical reactors comprise a hollow ceramic blade positioned across a gas stream flow or a stack of crossed hollow ceramic blades containing a channel or channels for flow of gas streams. Each channel has at least one channel wall disposed between a channel and a portion of an outer surface of the ceramic blade, or a common wall with adjacent blades in a stack comprising a gas-impervious mixed metal oxide material of a perovskite structure having electron conductivity and oxygen ion conductivity. The invention includes reactors comprising first and second zones seprated by gas-impervious mixed metal oxide material material having electron conductivity and oxygen ion conductivity. Prefered gas-impervious materials comprise at least one mixed metal oxide having a perovskite structure or perovskite-like structure. The invention includes, also, oxidation processes controlled by using these electrochemical reactors, and these reactions do not require an external source of electrical potential or any external electric circuit for oxidation to proceed.

Nano-Array Integrated Structured Catalysts: A New Paradigm upon Conventional Wash-Coated Monolithic Catalysts?

DOE PAGES

Weng, Junfei; Lu, Xingxu; Gao, Pu-Xian

2017-08-28

The monolithic catalyst, namely the structured catalyst, is one of the important categories of catalysts used in various fields, especially in catalytic exhaust after-treatment. Despite its successful application in conventional wash-coated catalysts in both mobile and stationary catalytic converters, washcoat-based technologies are facing multi-fold challenges, including: (1) high Pt-group metals (PGM) material loading being required, driving the market prices; (2) less-than ideal distribution of washcoats in typically square-shaped channels associated with pressure drop sacrifice; and (3) far from clear correlations between macroscopic washcoat structures and their catalytic performance. To tackle these challenges, the well-defined nanostructure array (nano-array)-integrated structured catalysts whichmore » we invented and developed recently have been proven to be a promising class of cost-effective and efficient devices that may complement or substitute wash-coated catalysts. This new type of structured catalysts is composed of honeycomb-structured monoliths, whose channel surfaces are grown in situ with a nano-array forest made of traditional binary transition metal oxide support such as Al 2O 3, CeO 2, Co 3O 4, MnO 2, TiO 2, and ZnO, or newer support materials including perovskite-type ABO3 structures, for example LaMnO 3, LaCoO 3, LaNiO, and LaFeO 3. The integration strategy parts from the traditional washcoat technique. Instead, an in situ nanomaterial assembly method is utilized, such as a hydro (solva-) thermal synthesis approach, in order to create sound structure robustness, and increase ease and complex-shaped substrate adaptability. Specifically, the critical fabrication procedures for nano-array structured catalysts include deposition of seeding layer, in situ growth of nano-array, and loading of catalytic materials. The generic methodology utilization in both the magnetic stirring batch process and continuous flow reactor synthesis offers the nano-array catalysts with great potential to be scaled up readily and cost-effectively. The tunability of the structure and catalytic performance could be achieved through morphology and geometry adjustment and guest atoms and defect manipulation, as well as composite nano-array catalyst manufacture. Excellent stabilities under various conditions were also present compared to conventional wash-coated catalysts.« less

Nano-Array Integrated Structured Catalysts: A New Paradigm upon Conventional Wash-Coated Monolithic Catalysts?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weng, Junfei; Lu, Xingxu; Gao, Pu-Xian

The monolithic catalyst, namely the structured catalyst, is one of the important categories of catalysts used in various fields, especially in catalytic exhaust after-treatment. Despite its successful application in conventional wash-coated catalysts in both mobile and stationary catalytic converters, washcoat-based technologies are facing multi-fold challenges, including: (1) high Pt-group metals (PGM) material loading being required, driving the market prices; (2) less-than ideal distribution of washcoats in typically square-shaped channels associated with pressure drop sacrifice; and (3) far from clear correlations between macroscopic washcoat structures and their catalytic performance. To tackle these challenges, the well-defined nanostructure array (nano-array)-integrated structured catalysts whichmore » we invented and developed recently have been proven to be a promising class of cost-effective and efficient devices that may complement or substitute wash-coated catalysts. This new type of structured catalysts is composed of honeycomb-structured monoliths, whose channel surfaces are grown in situ with a nano-array forest made of traditional binary transition metal oxide support such as Al 2O 3, CeO 2, Co 3O 4, MnO 2, TiO 2, and ZnO, or newer support materials including perovskite-type ABO3 structures, for example LaMnO 3, LaCoO 3, LaNiO, and LaFeO 3. The integration strategy parts from the traditional washcoat technique. Instead, an in situ nanomaterial assembly method is utilized, such as a hydro (solva-) thermal synthesis approach, in order to create sound structure robustness, and increase ease and complex-shaped substrate adaptability. Specifically, the critical fabrication procedures for nano-array structured catalysts include deposition of seeding layer, in situ growth of nano-array, and loading of catalytic materials. The generic methodology utilization in both the magnetic stirring batch process and continuous flow reactor synthesis offers the nano-array catalysts with great potential to be scaled up readily and cost-effectively. The tunability of the structure and catalytic performance could be achieved through morphology and geometry adjustment and guest atoms and defect manipulation, as well as composite nano-array catalyst manufacture. Excellent stabilities under various conditions were also present compared to conventional wash-coated catalysts.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spathis, C., E-mail: cspathis@ece.upatras.gr; Birbas, A.; Georgakopoulou, K.

Device white noise levels in short channel Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) dictate the performance and reliability of high-frequency circuits ranging from high-speed microprocessors to Low-Noise Amplifiers (LNAs) and microwave circuits. Recent experimental noise measurements with very short devices demonstrate the existence of suppressed shot noise, contrary to the predictions of classical channel thermal noise models. In this work we show that, as the dimensions continue to shrink, shot noise has to be considered when the channel resistance becomes comparable to the barrier resistance at the source-channel junction. By adopting a semi-classical approach and taking retrospectively into account transport, short-channel andmore » quantum effects, we investigate the partitioning between shot and thermal noise, and formulate a predictive model that describes the noise characteristics of modern devices.« less

Steam reforming of n-hexane on pellet and monolithic catalyst beds. A comparative study on improvements due to heat transfer

NASA Technical Reports Server (NTRS)

1981-01-01

Monolithic catalysts with higher available active surface areas and better thermal conductivity than conventional pellets beds, making possible the steam reforming of fuels heavier than naphtha, were examined. Performance comparisons were made between conventional pellet beds and honeycomb monolith catalysts using n-hexane as the fuel. Metal-supported monoliths were examined. These offer higher structural stability and higher thermal conductivity than ceramic supports. Data from two metal monoliths of different nickel catalyst loadings were compared to pellets under the same operating conditions. Improved heat transfer and better conversion efficiencies were obtained with the monolith having higher catalyst loading. Surface-gas interaction was observed throughout the length of the monoliths.

Ultra Low Noise Infrared Detector Amplifier for Next Generation Standoff Detector

DTIC Science & Technology

2016-02-18

some mismatches. The formation of a heterojunction for the channel entails creating a sufficient degree of difference between the bandgap of the...metal oxide (MOS) capacitor, thereby isolating the ground from dc. EPIR Technologies, Inc. Proprietary Information – Exempt From FOIA 67 Figure

Development of double chain phosphatidylcholine functionalized polymeric monoliths for immobilized artificial membrane chromatography.

PubMed

Wang, Qiqin; Peng, Kun; Chen, Weijia; Cao, Zhen; Zhu, Peijie; Zhao, Yumei; Wang, Yuqiang; Zhou, Haibo; Jiang, Zhengjin

2017-01-06

This study described a simple synthetic methodology for preparing biomembrane mimicking monolithic column. The suggested approach not only simplifies the preparation procedure but also improves the stability of double chain phosphatidylcholine (PC) functionalized monolithic column. The physicochemical properties of the optimized monolithic column were characterized by scanning electron microscopy, energy-dispersive X-ray spectrometry, and nano-LC. Satisfactory column permeability, efficiency, stability and reproducibility were obtained on this double chain PC functionalized monolithic column. It is worth noting that the resulting polymeric monolith exhibits great potential as a useful alternative of commercial immobilized artificial membrane (IAM) columns for in vitro predication of drug-membrane interactions. Furthermore, the comparative study of both double chain and single chain PC functionalized monoliths indicates that the presence or absence of glycerol backbone and the number of acyl chains are not decisive for the predictive ability of IAM monoliths on drug-membrane interactions. This novel PC functionalized monolithic column also exhibited good selectivity for a protein mixture and a set of pharmaceutical compounds. Copyright © 2016 Elsevier B.V. All rights reserved.

Ultra high spatial and temporal resolution breast imaging at 7T.

PubMed

van de Bank, B L; Voogt, I J; Italiaander, M; Stehouwer, B L; Boer, V O; Luijten, P R; Klomp, D W J

2013-04-01

There is a need to obtain higher specificity in the detection of breast lesions using MRI. To address this need, Dynamic Contrast-Enhanced (DCE) MRI has been combined with other structural and functional MRI techniques. Unfortunately, owing to time constraints structural images at ultra-high spatial resolution can generally not be obtained during contrast uptake, whereas the relatively low spatial resolution of functional imaging (e.g. diffusion and perfusion) limits the detection of small lesions. To be able to increase spatial as well as temporal resolution simultaneously, the sensitivity of MR detection needs to increase as well as the ability to effectively accelerate the acquisition. The required gain in signal-to-noise ratio (SNR) can be obtained at 7T, whereas acceleration can be obtained with high-density receiver coil arrays. In this case, morphological imaging can be merged with DCE-MRI, and other functional techniques can be obtained at higher spatial resolution, and with less distortion [e.g. Diffusion Weighted Imaging (DWI)]. To test the feasibility of this concept, we developed a unilateral breast coil for 7T. It comprises a volume optimized dual-channel transmit coil combined with a 30-channel receive array coil. The high density of small coil elements enabled efficient acceleration in any direction to acquire ultra high spatial resolution MRI of close to 0.6 mm isotropic detail within a temporal resolution of 69 s, high spatial resolution MRI of 1.5 mm isotropic within an ultra high temporal resolution of 6.7 s and low distortion DWI at 7T, all validated in phantoms, healthy volunteers and a patient with a lesion in the right breast classified as Breast Imaging Reporting and Data System (BI-RADS) IV. Copyright © 2012 John Wiley & Sons, Ltd.

High aspect ratio catalytic reactor and catalyst inserts therefor

DOEpatents

Lin, Jiefeng; Kelly, Sean M.

2018-04-10

The present invention relates to high efficient tubular catalytic steam reforming reactor configured from about 0.2 inch to about 2 inch inside diameter high temperature metal alloy tube or pipe and loaded with a plurality of rolled catalyst inserts comprising metallic monoliths. The catalyst insert substrate is formed from a single metal foil without a central supporting structure in the form of a spiral monolith. The single metal foil is treated to have 3-dimensional surface features that provide mechanical support and establish open gas channels between each of the rolled layers. This unique geometry accelerates gas mixing and heat transfer and provides a high catalytic active surface area. The small diameter, high aspect ratio tubular catalytic steam reforming reactors loaded with rolled catalyst inserts can be arranged in a multi-pass non-vertical parallel configuration thermally coupled with a heat source to carry out steam reforming of hydrocarbon-containing feeds. The rolled catalyst inserts are self-supported on the reactor wall and enable efficient heat transfer from the reactor wall to the reactor interior, and lower pressure drop than known particulate catalysts. The heat source can be oxygen transport membrane reactors.

Reflectively Coupled Waveguide Photodetector for High Speed Optical Interconnection

PubMed Central

Hsu*, Shih-Hsiang

2010-01-01

To fully utilize GaAs high drift mobility, techniques to monolithically integrate In0.53Ga0.47As p-i-n photodetectors with GaAs based optical waveguides using total internal reflection coupling are reviewed. Metal coplanar waveguides, deposited on top of the polyimide layer for the photodetector’s planarization and passivation, were then uniquely connected as a bridge between the photonics and electronics to illustrate the high-speed monitoring function. The photodetectors were efficiently implemented and imposed on the echelle grating circle for wavelength division multiplexing monitoring. In optical filtering performance, the monolithically integrated photodetector channel spacing was 2 nm over the 1,520–1,550 nm wavelength range and the pass band was 1 nm at the −1 dB level. For high-speed applications the full-width half-maximum of the temporal response and 3-dB bandwidth for the reflectively coupled waveguide photodetectors were demonstrated to be 30 ps and 11 GHz, respectively. The bit error rate performance of this integrated photodetector at 10 Gbit/s with 27-1 long pseudo-random bit sequence non-return to zero input data also showed error-free operation. PMID:22163502

Development and characterization of methacrylate-based hydrazide monoliths for oriented immobilization of antibodies.

PubMed

Brne, P; Lim, Y-P; Podgornik, A; Barut, M; Pihlar, B; Strancar, A

2009-03-27

Convective interaction media (CIM; BIA Separations) monoliths are attractive stationary phases for use in affinity chromatography because they enable fast affinity binding, which is a consequence of convectively enhanced mass transport. This work focuses on the development of novel CIM hydrazide (HZ) monoliths for the oriented immobilization of antibodies. Adipic acid dihydrazide (AADH) was covalently bound to CIM epoxy monoliths to gain hydrazide groups on the monolith surface. Two different antibodies were afterwards immobilized to hydrazide functionalized monolithic columns and prepared columns were tested for their selectivity. One column was further tested for the dynamic binding capacity.

Germanium Based Field-Effect Transistors: Challenges and Opportunities

PubMed Central

Goley, Patrick S.; Hudait, Mantu K.

2014-01-01

The performance of strained silicon (Si) as the channel material for today’s metal-oxide-semiconductor field-effect transistors may be reaching a plateau. New channel materials with high carrier mobility are being investigated as alternatives and have the potential to unlock an era of ultra-low-power and high-speed microelectronic devices. Chief among these new materials is germanium (Ge). This work reviews the two major remaining challenges that Ge based devices must overcome if they are to replace Si as the channel material, namely, heterogeneous integration of Ge on Si substrates, and developing a suitable gate stack. Next, Ge is compared to compound III-V materials in terms of p-channel device performance to review how it became the first choice for PMOS devices. Different Ge device architectures, including surface channel and quantum well configurations, are reviewed. Finally, state-of-the-art Ge device results and future prospects are also discussed. PMID:28788569

A 700 V narrow channel nJFET with low pinch-off voltage and suppressed drain-induced barrier lowering effect

NASA Astrophysics Data System (ADS)

Mao, Kun; Qiao, Ming; Zhang, WenTong; Zhang, Bo; Li, Zhaoji

2014-11-01

This paper proposes a 700 V narrow channel region triple-RESURF (reduced surface field) n-type junction field-effect transistor (NCT-nJFET). Compared to traditional structures, low pinch-off voltage (VP) with unobvious drain-induced barrier lowering (DIBL) effect and large saturated current (IDsat) are achieved. This is because p-type buried layer (Pbury) and PWELL are introduced to shape narrow n-type channel in JFET channel region. DIBL sensitivity (SDIBL) is firstly introduced in this paper to analyze the DIBL effect of high-voltage long-channel JFET. Ultra-high breakdown voltage is obtained by triple RESURF technology. Experimental results show that proposed NCT-nJFET achieves 24-V VP, 3.5% SDIBL, 2.3-mA IDsat, 800-V OFF-state breakdown voltage (OFF-BV) and 650-V ON-state breakdown voltage when VGS equals 0 V (ON-BV).

Superior Tensile Ductility in Bulk Metallic Glass with Gradient Amorphous Structure

PubMed Central

Wang, Q.; Yang, Y.; Jiang, H.; Liu, C. T.; Ruan, H. H.; Lu, J.

2014-01-01

Over centuries, structural glasses have been deemed as a strong yet inherently ‘brittle’ material due to their lack of tensile ductility. However, here we report bulk metallic glasses exhibiting both a high strength of ~2 GPa and an unprecedented tensile elongation of 2–4% at room temperature. Our experiments have demonstrated that intense structural evolution can be triggered in theses glasses by the carefully controlled surface mechanical attrition treatment, leading to the formation of gradient amorphous microstructures across the sample thickness. As a result, the engineered amorphous microstructures effectively promote multiple shear banding while delay cavitation in the bulk metallic glass, thus resulting in superior tensile ductility. The outcome of our research uncovers an unusual work-hardening mechanism in monolithic bulk metallic glasses and demonstrates a promising yet low-cost strategy suitable for producing large-sized, ultra-strong and stretchable structural glasses. PMID:24755683

Electron beam pumped semiconductor laser

NASA Technical Reports Server (NTRS)

Hug, William F. (Inventor); Reid, Ray D. (Inventor)

2009-01-01

Electron-beam-pumped semiconductor ultra-violet optical sources (ESUVOSs) are disclosed that use ballistic electron pumped wide bandgap semiconductor materials. The sources may produce incoherent radiation and take the form of electron-beam-pumped light emitting triodes (ELETs). The sources may produce coherent radiation and take the form of electron-beam-pumped laser triodes (ELTs). The ELTs may take the form of electron-beam-pumped vertical cavity surface emitting lasers (EVCSEL) or edge emitting electron-beam-pumped lasers (EEELs). The semiconductor medium may take the form of an aluminum gallium nitride alloy that has a mole fraction of aluminum selected to give a desired emission wavelength, diamond, or diamond-like carbon (DLC). The sources may be produced from discrete components that are assembled after their individual formation or they may be produced using batch MEMS-type or semiconductor-type processing techniques to build them up in a whole or partial monolithic manner, or combination thereof.

Brief report: How short is too short? An ultra-brief measure of the big-five personality domains implicates "agreeableness" as a risk for all-cause mortality.

PubMed

Chapman, Benjamin P; Elliot, Ari J

2017-08-01

Controversy exists over the use of brief Big Five scales in health studies. We investigated links between an ultra-brief measure, the Big Five Inventory-10, and mortality in the General Social Survey. The Agreeableness scale was associated with elevated mortality risk (hazard ratio = 1.26, p = .017). This effect was attributable to the reversed-scored item "Tends to find fault with others," so that greater fault-finding predicted lower mortality risk. The Conscientiousness scale approached meta-analytic estimates, which were not precise enough for significance. Those seeking Big Five measurement in health studies should be aware that the Big Five Inventory-10 may yield unusual results.

Inhibited-coupling HC-PCF based beam-delivery-system for high power green industrial lasers

NASA Astrophysics Data System (ADS)

Chafer, M.; Gorse, A.; Beaudou, B.; Lekiefs, Q.; Maurel, M.; Debord, B.; Gérôme, F.; Benabid, F.

2018-02-01

We report on an ultra-low loss Hollow-Core Photonic Crystal Fiber (HC-PCF) beam delivery system (GLO-GreenBDS) for high power ultra-short pulse lasers operating in the green spectral range (including 515 nm and 532 nm). The GLOBDS- Green combines ease-of-use, high laser-coupling efficiency, robustness and industrial compatible cabling. It comprises a pre-aligned laser-injection head, a sheath-cable protected HC-PCF and a modular fiber-output head. It enables fiber-core gas loading and evacuation in a hermetic fashion. A 5 m long GLO-BDS were demonstrated for a green short pulse laser with a transmission coefficient larger than 80%, and a laser output profile close to single-mode (M2 <1.3).

Enhanced water window x-ray emission from in situ formed carbon clusters irradiated by intense ultra-short laser pulses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chakravarty, U.; Rao, B. S.; Arora, V.

Enhanced water window x-ray emission (23–44 Å) from carbon clusters, formed in situ using a pre-pulse, irradiated by intense (I > 10{sup 17} W/cm{sup 2}) ultra-short laser pulse, is demonstrated. An order of magnitude x-ray enhancement over planar graphite target is observed in carbon clusters, formed by a sub-ns pre-pulse, interacting with intense main pulse after a delay. The effect of the delay and the duration of the main pulse is studied for optimizing the x-ray emission in the water window region. This x-ray source has added advantages of being an efficient, high repetition rate, and low debris x-ray source.

Analysis of Unmanned Undersea Vehicle (UUV) Architectures and an Assessment of UUV Integration into Undersea Applications

DTIC Science & Technology

2010-09-01

Synthetic Long Baseline SSS Side Scan Sonar TCS Time Critical Strike TRL Technology Readiness Level U.S. United States UHF Ultra High...Frequency UN United Nation USBL Ultra Short Baseline UUV Unmanned Undersea Vehicle UUVMP Unmanned Undersea Vehicle Master Plan V Volts...Wilmington, “NURC/SEGM Capabilities: Deepwater AUV,” University of North Carolina Wilmington Web site [Online], Available: http://www.uncw.edu/nurc/auv

Wideband monolithically integrated front-end subsystems and components

NASA Astrophysics Data System (ADS)

Mruk, Joseph Rene

This thesis presents the analysis, design, and measurements of passive, monolithically integrated, wideband recta-coax and printed circuit board front-end components. Monolithic fabrication of antennas, impedance transformers, filters, and transitions lowers manufacturing costs by reducing assembly time and enhances performance by removing connectors and cabling between the devices. Computational design, fabrication, and measurements are used to demonstrate the capabilities of these front-end assemblies. Two-arm wideband planar log-periodic antennas fed using a horizontal feed that allows for filters and impedance transformers to be readily fabricated within the radiating region of the antenna are demonstrated. At microwave frequencies, low-cost printed circuit board processes are typically used to produce planar devices. A 1.8 to 11 GHz two-arm planar log-periodic antenna is designed with a monolithically integrated impedance transformer. Band rejection methods based on modifying the antenna aperture, use of an integrated filter, and the application of both methods are investigated with realized gain suppressions of over 25 dB achieved. The ability of standard circuit board technology to fabricate millimeter-wave devices up to 110 GHz is severely limited. Thin dielectrics are required to prevent the excitation of higher order modes in the microstrip substrate. Fabricating the thin line widths required for the antenna aperture also becomes prohibitively challenging. Surface micro-machining typically used in the fabrication of MEMS devices is capable of producing the extremely small features that can be used to fabricate antennas extending through W-band. A directly RF fed 18 to 110 GHz planar log-periodic antenna is developed. The antenna is fabricated with an integrated impedance transformer and additional transitions for measurement characterization. Singly terminated low-loss wideband millimeter-wave filters operating over V- and W- band are developed. High quality performance of an 18 to 100 GHz front-end is realized by dividing the single instantaneous antenna into two apertures operating from 18 to 50 and 50 to 100 GHz. Each channel features an impedance transformer, low-pass (low-frequency) or band-pass (high-frequency) filter, and grounded CPW launch. This dual-aperture front-end demonstrates that micromachining technology is now capable of fabricating broadband millimeter-wave components with a high degree of integration.

Revolutionary systems for catalytic combustion and diesel catalytic particulate traps.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stuecker, John Nicholas; Witze, Peter O.; Ferrizz, Robert Matthew

2004-12-01

This report is a summary of an LDRD project completed for the development of materials and structures conducive to advancing the state of the art for catalyst supports and diesel particulate traps. An ancillary development for bio-medical bone scaffolding was also realized. Traditionally, a low-pressure drop catalyst support, such as a ceramic honeycomb monolith, is used for catalytic reactions that require high flow rates of gases at high-temperatures. A drawback to the traditional honeycomb monoliths under these operating conditions is poor mass transfer to the catalyst surface in the straight-through channels. ''Robocasting'' is a unique process developed at Sandia Nationalmore » Laboratories that can be used to manufacture ceramic monoliths with alternative 3-dimensional geometries, providing tortuous pathways to increase mass transfer while maintaining low-pressure drops. These alternative 3-dimensional geometries may also provide a foundation for the development of self-regenerating supports capable of trapping and combusting soot particles from a diesel engine exhaust stream. This report describes the structures developed and characterizes the improved catalytic performance that can result. The results show that, relative to honeycomb monolith supports, considerable improvement in mass transfer efficiency is observed for robocast samples synthesized using an FCC-like geometry of alternating rods. Also, there is clearly a trade-off between enhanced mass transfer and increased pressure drop, which can be optimized depending on the particular demands of a given application. Practical applications include the combustion of natural gas for power generation, production of syngas, and hydrogen reforming reactions. The robocast lattice structures also show practicality for diesel particulate trapping. Preliminary results for trapping efficiency are reported as well as the development of electrically resistive lattices that can regenerate the structure by combusting the trapped soot. During this project an ancillary bio-medical application was discovered for lattices of hydroxyapatite. These structures show promise as bone scaffolds for the reparation of damaged bone. A case study depicting the manufacture of a customized device that fits into a damaged mandible is described.« less

Short Pulse High Brightness X-ray Production with the PLEIADES Thomson Scattering Source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anderson, S G; Barty, C P J; Betts, S M

2003-07-01

We describe PLEIADES, a compact, tunable, high-brightness, ultra-short pulse, Thomson x-ray source. The peak brightness of the source is expected to exceed 10{sup 20} photons/s/0.1% bandwidth/mm{sup 2}/mrad{sup 2}. Initial results are reported and compared to theoretical calculations.

Model stream channel testing of a UV-transparent polymer-based passive sampler for ultra-low-cost water screening applications

EPA Science Inventory

Passive samplers are increasingly being considered for analyses of waters for screening applications, to monitor for the presence of unwanted chemical compounds. Passive samplers typically work by accumulating and concentrating chemicals from the surrounding water over time, all...

Department of the Navy Fiscal Year 2011 Annual Financial Report. Mission Ready: Managing Risk and Meeting Objectives

DTIC Science & Technology

2011-01-01

Earthquake Relief Effort Haiti Migrant Operational Support Deepwater Horizon Oil Spill Tennessee Flooding Pakistan Flooding Typhoon Megi (Philippines) Natural...provide relevant capabilities and to enable Operationally Responsive Space. TacSat-4 provides ten Ultra High Frequency (UHF) channels, which can be used

Void Formation/Elimination and Viscoelastic Response of Polyphenylsilsesquioxane Monolith.

PubMed

Daiko, Yusuke; Oda, Yuki; Honda, Sawao; Iwamoto, Yuji

2018-05-19

Polyphenylsilsesquioxane (PhSiO 3/2 ) particles as an organic-inorganic hybrid were prepared using sol-gel method, and monolithic samples were obtained via a warm-pressing. The reaction mechanism of particles' polymerization and transformation to the monolith under the warm-press were investigated using solid state 29 Si nuclear magnetic resonance (NMR) spectrometer, thermal gravimetric-differential thermal analyzer (TG-DTA), mass spectrometer (MS) and scanning electron microscope (SEM). Transparent and void-free monoliths are successfully obtained by warm-pressing above 180 °C. Both the terminal ⁻OH groups on particles' surface and warm-pressing are necessary for preparation of void-free PhSiO 3/2 monolith. From the load-displacement measurement at various temperatures, a viscoelastic deformation is seen for PhSiO 3/2 monolith with voids. On the other hand, an elastic deformation is seen for void-free PhSiO 3/2 monolith, and the void-free monolith shows much higher breakdown voltage.

Time Domain and Frequency Domain Deterministic Channel Modeling for Tunnel/Mining Environments.

PubMed

Zhou, Chenming; Jacksha, Ronald; Yan, Lincan; Reyes, Miguel; Kovalchik, Peter

2017-01-01

Understanding wireless channels in complex mining environments is critical for designing optimized wireless systems operated in these environments. In this paper, we propose two physics-based, deterministic ultra-wideband (UWB) channel models for characterizing wireless channels in mining/tunnel environments - one in the time domain and the other in the frequency domain. For the time domain model, a general Channel Impulse Response (CIR) is derived and the result is expressed in the classic UWB tapped delay line model. The derived time domain channel model takes into account major propagation controlling factors including tunnel or entry dimensions, frequency, polarization, electrical properties of the four tunnel walls, and transmitter and receiver locations. For the frequency domain model, a complex channel transfer function is derived analytically. Based on the proposed physics-based deterministic channel models, channel parameters such as delay spread, multipath component number, and angular spread are analyzed. It is found that, despite the presence of heavy multipath, both channel delay spread and angular spread for tunnel environments are relatively smaller compared to that of typical indoor environments. The results and findings in this paper have application in the design and deployment of wireless systems in underground mining environments.

Time Domain and Frequency Domain Deterministic Channel Modeling for Tunnel/Mining Environments

PubMed Central

Zhou, Chenming; Jacksha, Ronald; Yan, Lincan; Reyes, Miguel; Kovalchik, Peter

2018-01-01

Understanding wireless channels in complex mining environments is critical for designing optimized wireless systems operated in these environments. In this paper, we propose two physics-based, deterministic ultra-wideband (UWB) channel models for characterizing wireless channels in mining/tunnel environments — one in the time domain and the other in the frequency domain. For the time domain model, a general Channel Impulse Response (CIR) is derived and the result is expressed in the classic UWB tapped delay line model. The derived time domain channel model takes into account major propagation controlling factors including tunnel or entry dimensions, frequency, polarization, electrical properties of the four tunnel walls, and transmitter and receiver locations. For the frequency domain model, a complex channel transfer function is derived analytically. Based on the proposed physics-based deterministic channel models, channel parameters such as delay spread, multipath component number, and angular spread are analyzed. It is found that, despite the presence of heavy multipath, both channel delay spread and angular spread for tunnel environments are relatively smaller compared to that of typical indoor environments. The results and findings in this paper have application in the design and deployment of wireless systems in underground mining environments.† PMID:29457801

Birth of an intense pulsed muon source, J-PARC MUSE

NASA Astrophysics Data System (ADS)

Miyake, Yasuhiro; Shimomura, Koichiro; Kawamura, Naritoshi; Strasser, Patrick; Makimura, Shunsuke; Koda, Akihiro; Fujimori, Hiroshi; Nakahara, Kazutaka; Kadono, Ryosuke; Kato, Mineo; Takeshita, Soshi; Nishiyama, Kusuo; Higemoto, Wataru; Ishida, Katsuhiko; Matsuzaki, Teiichiro; Matsuda, Yasuyuki; Nagamine, Kanetada

2009-04-01

The muon science facility (MUSE), along with neutron, hadron, and neutrino facilities, is one of the experimental areas of the J-PARC (Japan Proton Accelerator Research Complex) project, which was approved for construction between 2001 and 2008. The MUSE facility is located in the Materials and Life Science Facility (MLF), which is a building integrated to include both neutron and muon science programs. Construction of the MLF building was started at the beginning of 2004, and was recently completed at the end of the 2006 fiscal year. We have been working on the installation of the beamline components, expecting the first muon beam in the autumn of 2008. For Phase 1, we are planning to install one superconducting decay/surface channel with a modest-acceptance (about 40 mSr) pion injector, with an estimated surface muon (μ+) rate of 3×107/s and a beam size of 25 mm diameter, and a corresponding decay muon (μ+/μ-) rate of 106/s for 60 MeV/ c (up to 107/s for 120 MeV/ c) with a beam size of 50 mm diameter. These intensities correspond to more than 10-times what is available at the RIKEN/RAL muon facility, which currently possess the most intense pulsed muon beams in the world. In addition to Phase 1, we are planning to install, a surface muon channel with a modest-acceptance (about 50 mSr), mainly for experiments related to material sciences, and a super-omega muon channel with a large acceptance of 400 mSr. In the case of the super-omega muon channel, the goal is to extract 4×108 surface muons/s for the generation of ultra-slow muons and 1×107 negative cloud muons/s with a momentum of 30-60 MeV/ c. One of the important goals for this beamline is to generate intense ultra-slow muons at MUSE, utilizing an intense pulsed VUV laser system. 104-106 ultra-slow muons/s are expected, which will allow for an extension of μSR into the area of thin film and surface science. At this symposium, the current status of J-PARC MUSE will be reported.