High resolution separations of charge variants and disulfide isomers of monoclonal antibodies and antibody drug conjugates using ultra-high voltage capillary electrophoresis with high electric field strength.

PubMed

Henley, W Hampton; He, Yan; Mellors, J Scott; Batz, Nicholas G; Ramsey, J Michael; Jorgenson, James W

2017-11-10

Ultra-high voltage capillary electrophoresis with high electric field strength has been applied to the separation of the charge variants, drug conjugates, and disulfide isomers of monoclonal antibodies. Samples composed of many closely related species are difficult to resolve and quantify using traditional analytical instrumentation. High performance instrumentation can often save considerable time and effort otherwise spent on extensive method development. Ideally, the resolution obtained for a given CE buffer system scales with the square root of the applied voltage. Currently available commercial CE instrumentation is limited to an applied voltage of approximately 30kV and a maximum electric field strength of 1kV/cm due to design limitations. The instrumentation described here is capable of safely applying potentials of at least 120kV with electric field strengths over 2000V/cm, potentially doubling the resolution of the best conventional CE buffer/capillary systems while decreasing analysis time in some applications. Separations of these complex mixtures using this new instrumentation demonstrate the potential of ultra-high voltage CE to identify the presence of previously unresolved components and to reduce analysis time for complex mixtures of antibody variants and drug conjugates. Copyright © 2017 Elsevier B.V. All rights reserved.

A fibre-coupled UHV-compatible variable angle reflection-absorption UV/visible spectrometer

NASA Astrophysics Data System (ADS)

Stubbing, J. W.; Salter, T. L.; Brown, W. A.; Taj, S.; McCoustra, M. R. S.

2018-05-01

We present a novel UV/visible reflection-absorption spectrometer for determining the refractive index, n, and thicknesses, d, of ice films. Knowledge of the refractive index of these films is of particular relevance to the astrochemical community, where they can be used to model radiative transfer and spectra of various regions of space. In order to make these models more accurate, values of n need to be recorded under astronomically relevant conditions, that is, under ultra-high vacuum (UHV) and cryogenic cooling. Several design considerations were taken into account to allow UHV compatibility combined with ease of use. The key design feature is a stainless steel rhombus coupled to an external linear drive (z-shift) allowing a variable reflection geometry to be achieved, which is necessary for our analysis. Test data for amorphous benzene ice are presented as a proof of concept, the film thickness, d, was found to vary linearly with surface exposure, and a value for n of 1.43 ± 0.07 was determined.

Combined UHV/high-pressure catalysis setup for depth-resolved near-surface spectroscopic characterization and catalytic testing of model catalysts

NASA Astrophysics Data System (ADS)

Mayr, Lukas; Rameshan, Raffael; Klötzer, Bernhard; Penner, Simon; Rameshan, Christoph

2014-05-01

An ultra-high vacuum (UHV) setup for "real" and "inverse" model catalyst preparation, depth-resolved near-surface spectroscopic characterization, and quantification of catalytic activity and selectivity under technologically relevant conditions is described. Due to the all-quartz reactor attached directly to the UHV-chamber, transfer of the catalyst for in situ testing without intermediate contact to the ambient is possible. The design of the UHV-compatible re-circulating batch reactor setup allows the study of reaction kinetics under close to technically relevant catalytic conditions up to 1273 K without contact to metallic surfaces except those of the catalyst itself. With the attached differentially pumped exchangeable evaporators and the quartz-microbalance thickness monitoring equipment, a reproducible, versatile, and standardised sample preparation is possible. For three-dimensional near-surface sample characterization, the system is equipped with a hemispherical analyser for X-ray photoelectron spectroscopy (XPS), electron-beam or X-ray-excited Auger-electron spectroscopy, and low-energy ion scattering measurements. Due the dedicated geometry of the X-ray gun (54.7°, "magic angle") and the rotatable sample holder, depth analysis by angle-resolved XPS measurements can be performed. Thus, by the combination of characterisation methods with different information depths, a detailed three-dimensional picture of the electronic and geometric structure of the model catalyst can be obtained. To demonstrate the capability of the described system, comparative results for depth-resolved sample characterization and catalytic testing in methanol steam reforming on PdGa and PdZn near-surface intermetallic phases are shown.

Industry-relevant magnetron sputtering and cathodic arc ultra-high vacuum deposition system for in situ x-ray diffraction studies of thin film growth using high energy synchrotron radiation.

PubMed

Schroeder, J L; Thomson, W; Howard, B; Schell, N; Näslund, L-Å; Rogström, L; Johansson-Jõesaar, M P; Ghafoor, N; Odén, M; Nothnagel, E; Shepard, A; Greer, J; Birch, J

2015-09-01

We present an industry-relevant, large-scale, ultra-high vacuum (UHV) magnetron sputtering and cathodic arc deposition system purposefully designed for time-resolved in situ thin film deposition/annealing studies using high-energy (>50 keV), high photon flux (>10(12) ph/s) synchrotron radiation. The high photon flux, combined with a fast-acquisition-time (<1 s) two-dimensional (2D) detector, permits time-resolved in situ structural analysis of thin film formation processes. The high-energy synchrotron-radiation based x-rays result in small scattering angles (<11°), allowing large areas of reciprocal space to be imaged with a 2D detector. The system has been designed for use on the 1-tonne, ultra-high load, high-resolution hexapod at the P07 High Energy Materials Science beamline at PETRA III at the Deutsches Elektronen-Synchrotron in Hamburg, Germany. The deposition system includes standard features of a typical UHV deposition system plus a range of special features suited for synchrotron radiation studies and industry-relevant processes. We openly encourage the materials research community to contact us for collaborative opportunities using this unique and versatile scientific instrument.

Collagen production of osteoblasts revealed by ultra-high voltage electron microscopy.

PubMed

Hosaki-Takamiya, Rumiko; Hashimoto, Mana; Imai, Yuichi; Nishida, Tomoki; Yamada, Naoko; Mori, Hirotaro; Tanaka, Tomoyo; Kawanabe, Noriaki; Yamashiro, Takashi; Kamioka, Hiroshi

2016-09-01

In the bone, collagen fibrils form a lamellar structure called the "twisted plywood-like model." Because of this unique structure, bone can withstand various mechanical stresses. However, the formation of this structure has not been elucidated because of the difficulty of observing the collagen fibril production of the osteoblasts via currently available methods. This is because the formation occurs in the very limited space between the osteoblast layer and bone matrix. In this study, we used ultra-high-voltage electron microscopy (UHVEM) to observe collagen fibril production three-dimensionally. UHVEM has 3-MV acceleration voltage and enables us to use thicker sections. We observed collagen fibrils that were beneath the cell membrane of osteoblasts elongated to the outside of the cell. We also observed that osteoblasts produced collagen fibrils with polarity. By using AVIZO software, we observed collagen fibrils produced by osteoblasts along the contour of the osteoblasts toward the bone matrix area. Immediately after being released from the cell, the fibrils run randomly and sparsely. But as they recede from the osteoblast, the fibrils began to run parallel to the definite direction and became thick, and we observed a periodical stripe at that area. Furthermore, we also observed membrane structures wrapped around filamentous structures inside the osteoblasts. The filamentous structures had densities similar to the collagen fibrils and a columnar form and diameter. Our results suggested that collagen fibrils run parallel and thickly, which may be related to the lateral movement of the osteoblasts. UHVEM is a powerful tool for observing collagen fibril production.

Ultra-low power high temperature and radiation hard complementary metal-oxide-semiconductor (CMOS) silicon-on-insulator (SOI) voltage reference.

PubMed

Boufouss, El Hafed; Francis, Laurent A; Kilchytska, Valeriya; Gérard, Pierre; Simon, Pascal; Flandre, Denis

2013-12-13

This paper presents an ultra-low power CMOS voltage reference circuit which is robust under biomedical extreme conditions, such as high temperature and high total ionized dose (TID) radiation. To achieve such performances, the voltage reference is designed in a suitable 130 nm Silicon-on-Insulator (SOI) industrial technology and is optimized to work in the subthreshold regime of the transistors. The design simulations have been performed over the temperature range of -40-200 °C and for different process corners. Robustness to radiation was simulated using custom model parameters including TID effects, such as mobilities and threshold voltages degradation. The proposed circuit has been tested up to high total radiation dose, i.e., 1 Mrad (Si) performed at three different temperatures (room temperature, 100 °C and 200 °C). The maximum drift of the reference voltage V(REF) depends on the considered temperature and on radiation dose; however, it remains lower than 10% of the mean value of 1.5 V. The typical power dissipation at 2.5 V supply voltage is about 20 μW at room temperature and only 75 μW at a high temperature of 200 °C. To understand the effects caused by the combination of high total ionizing dose and temperature on such voltage reference, the threshold voltages of the used SOI MOSFETs were extracted under different conditions. The evolution of V(REF) and power consumption with temperature and radiation dose can then be explained in terms of the different balance between fixed oxide charge and interface states build-up. The total occupied area including pad-ring is less than 0.09 mm2.

Process Properties of Electronic High Voltage Discharges Triggered by Ultra-short Pulsed Laser Filaments

NASA Astrophysics Data System (ADS)

Cvecek, Kristian; Gröschel, Benjamin; Schmidt, Michael

Remote processing of metallic workpieces by techniques based on electric arc discharge or laser irradiation for joining or cutting has a long tradition and is still being intensively investigated in present-day research. In applications that require high power processing, both approaches exhibit certain advantages and disadvantages that make them specific for a given task. While several hybrid approaches exist that try to combine the benefits of both techniques, none were as successful in providing a fixed electric discharge direction as discharges triggered by plasma filaments generated by ultra-short pulsed lasers. In this work we investigate spatial and temporal aspects of laser filament guided discharges and give an upper time delay between the filament creation and the electrical build-up of a dischargeable voltage for a successful filament triggered discharge.

Oxygen accumulation on metal surfaces investigated by XPS, AES and LEIS, an issue for sputter depth profiling under UHV conditions

NASA Astrophysics Data System (ADS)

Steinberger, R.; Celedón, C. E.; Bruckner, B.; Roth, D.; Duchoslav, J.; Arndt, M.; Kürnsteiner, P.; Steck, T.; Faderl, J.; Riener, C. K.; Angeli, G.; Bauer, P.; Stifter, D.

2017-07-01

Depth profiling using surface sensitive analysis methods in combination with sputter ion etching is a common procedure for thorough material investigations, where clean surfaces free of any contamination are essential. Hence, surface analytic studies are mostly performed under ultra-high vacuum (UHV) conditions, but the cleanness of such UHV environments is usually overrated. Consequently, the current study highlights the in principle known impact of the residual gas on metal surfaces (Fe, Mg, Al, Cr and Zn) for various surface analytics methods, like X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) and low-energy ion scattering (LEIS). The investigations with modern, state-of-the-art equipment showed different behaviors for the metal surfaces in UHV during acquisition: (i) no impact for Zn, even after long time, (ii) solely adsorption of oxygen for Fe, slight and slow changes for Cr and (iii) adsorption accompanied by oxide formation for Al and Mg. The efficiency of different counter measures was tested and the acquired knowledge was finally used for ZnMgAl coated steel to obtain accurate depth profiles, which exhibited before serious artifacts when data acquisition was performed in an inconsiderate way.

High voltage testing for the Majorana Demonstrator

DOE PAGES

Abgrall, N.; Arnquist, I. J.; Avignone, III, F. T.; ...

2016-04-04

The Majorana Collaboration is constructing the Majorana Demonstrator, an ultra-low background, 44-kg modular high-purity Ge (HPGe) detector array to search for neutrinoless double-beta decay in 76Ge. The phenomenon of surface micro-discharge induced by high-voltage has been studied in the context of the Majorana Demonstrator. This effect can damage the front-end electronics or mimic detector signals. To ensure the correct performance, every high-voltage cable and feedthrough must be capable of supplying HPGe detector operating voltages as high as 5 kV without exhibiting discharge. R&D measurements were carried out to understand the testing system and determine the optimum design configuration of themore » high-voltage path, including different improvements of the cable layout and feedthrough flange model selection. Every cable and feedthrough to be used at the Majorana Demonstrator was characterized and the micro-discharge effects during the Majorana Demonstrator commissioning phase were studied. Furthermore, a stable configuration has been achieved, and the cables and connectors can supply HPGe detector operating voltages without exhibiting discharge.« less

High voltage testing for the Majorana Demonstrator

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

Abgrall, N.; Arnquist, Isaac J.; Avignone, F. T.

2016-07-01

The Majorana Collaboration is constructing theMajorana Demonstrator, an ultra-low background, 44-kg modular high-purity Ge (HPGe) detector array to search for neutrinoless double-beta decay in 76Ge. The phenomenon of surface micro-discharge induced by high-voltage has been studied in the context of theMajorana Demonstrator. This effect can damage the front-end electronics or mimic detector signals. To ensure the correct performance, every high-voltage cable and feedthrough must be capable of supplying HPGe detector operating voltages as high as 5 kV without exhibiting discharge. R&D measurements were carried out to understand the testing system and determine the optimum design configuration of the high-voltage path,more » including different improvements of the cable layout and feedthrough flange model selection. Every cable and feedthrough to be used at the Majorana Demonstrator was characterized and the micro-discharge effects during theMajorana Demonstrator commissioning phase were studied. A stable configuration has been achieved, and the cables and connectors can supply HPGe detector operating voltages without exhibiting discharge.« less

A 32 kb 9T near-threshold SRAM with enhanced read ability at ultra-low voltage operation

NASA Astrophysics Data System (ADS)

Kim, Tony Tae-Hyoung; Lee, Zhao Chuan; Do, Anh Tuan

2018-01-01

Ultra-low voltage SRAMs are highly sought-after in energy-limited systems such as battery-powered and self-harvested SoCs. However, ultra-low voltage operation diminishes SRAM read bitline (RBL) sensing margin significantly. This paper tackles this issue by presenting a novel 9T cell with data-independent RBL leakage in combination with an RBL boosting technique for enhancing the sensing margin. The proposed technique automatically tracks process, temperature and voltage (PVT) variations for robust sensing margin enhancement. A test chip fabricated in 65 nm CMOS technology shows that the proposed scheme significantly enlarges the sensing margin compared to the conventional bitline sensing scheme. It also achieves the minimum operating voltage of 0.18 V and the minimum energy consumption of 0.92 J/access at 0.4 V. He received 2016 International Low Power Design Contest Award from ISLPED, a best paper award at 2014 and 2011 ISOCC, 2008 AMD/CICC Student Scholarship Award, 2008 Departmental Research Fellowship from Univ. of Minnesota, 2008 DAC/ISSCC Student Design Contest Award, 2008, 2001, and 1999 Samsung Humantec Thesis Award and, 2005 ETRI Journal Paper of the Year Award. He is an author/co-author of +100 journal and conference papers and has 17 US and Korean patents registered. His current research interests include low power and high performance digital, mixed- mode, and memory circuit design, ultra-low voltage circuits and systems design, variation and aging tolerant circuits and systems, and circuit techniques for 3D ICs. He serves as an associate editor of IEEE Transactions on VLSI Systems. He is an IEEE senior member and the Chair of IEEE Solid-State Circuits Society Singapore Chapter. He has served numerous conferences as a committee member.

Simulation study on AlGaN/GaN diode with Γ-shaped anode for ultra-low turn-on voltage

NASA Astrophysics Data System (ADS)

Wang, Zeheng; Chen, Wanjun; Wang, Fangzhou; Cao, Jun; Sun, Ruize; Ren, Kailin; Luo, Yi; Guo, Songnan; Wang, Zirui; Jin, Xiaosheng; Yang, Lei; Zhang, Bo

2018-05-01

An ultra-low turn-on voltage (VT) Γ-shaped anode AlGaN/GaN Schottky barrier diode (GA-SBD) is proposed via modeling and simulation for the first time, in which a Γ-shaped anode consists of a metal-2DEG junction together with a metal-AlGaN junction beside a shallowly recessed MIS field plate (MFP). An analytic forward current-voltage model matching the simulation results well is presented where an ultra-low VT of 0.08 V is obtained. The turn-on and blocking mechanisms are investigated to reveal the GA-SBD's great potential for applications of highly efficient power ICs.

Ultra high vacuum broad band high power microwave window

DOEpatents

Nguyen-Tuong, V.; Dylla, H.F. III

1997-11-04

An improved high vacuum microwave window has been developed that utilizes high density polyethylene coated on two sides with SiOx, SiNx, or a combination of the two. The resultant low dielectric and low loss tangent window creates a low outgassing, low permeation seal through which broad band, high power microwave energy may be passed. No matching device is necessary and the sealing technique is simple. The features of the window are broad band transmission, ultra-high vacuum compatibility with a simple sealing technique, low voltage standing wave ratio, high power transmission and low cost. 5 figs.

Ultra high vacuum broad band high power microwave window

DOEpatents

Nguyen-Tuong, Viet; Dylla, III, Henry Frederick

1997-01-01

An improved high vacuum microwave window has been developed that utilizes high density polyethylene coated on two sides with SiOx, SiNx, or a combination of the two. The resultant low dielectric and low loss tangent window creates a low outgassing, low permeation seal through which broad band, high power microwave energy may be passed. No matching device is necessary and the sealing technique is simple. The features of the window are broad band transmission, ultra-high vacuum compatibility with a simple sealing technique, low voltage standing wave ratio, high power transmission and low cost.

The detection of dissolved gases in transformer oil by gas chromatography with helium ionization detector

NASA Astrophysics Data System (ADS)

Deng, Xian-qin; Fang, Hua; Li, Min-xian

2017-07-01

The GC-PDD with the technology of valve cutting and helium ionization detector was used to analyze the dissolved gases in ultra-high voltage(UHV) and extra-high voltage(EHV) transformer oil. The detection limit(DL) reached ppb grade, especially for the featuring gas—C2H2 and H2, whose DL could reach 5ppb and 11ppb respectively. The test reproducibility of the instrument was about 1% and the correlation coefficient of standard curve-r is greater or equal to 0.99, which showed obvious advantage compared with normal GC. In addition, the auxiliary gas of H2 was not used in this instrument, which completely improved the safety performance. Thus, the application of GC-PDD has significant meaning in warning potential malfunction inside the ultra-high voltage transformer in advance.

Interwell coupling effect in Si/SiGe quantum wells grown by ultra high vacuum chemical vapor deposition

PubMed Central

Wang, Rui; Lu, Fen; Fan, Wei Jun; Liu, Chong Yang; Loh, Ter-Hoe; Nguyen, Hoai Son; Narayanan, Balasubramanian

2007-01-01

Si/Si0.66Ge0.34coupled quantum well (CQW) structures with different barrier thickness of 40, 4 and 2 nm were grown on Si substrates using an ultra high vacuum chemical vapor deposition (UHV-CVD) system. The samples were characterized using high resolution x-ray diffraction (HRXRD), cross-sectional transmission electron microscopy (XTEM) and photoluminescence (PL) spectroscopy. Blue shift in PL peak energy due to interwell coupling was observed in the CQWs following increase in the Si barrier thickness. The Si/SiGe heterostructure growth process and theoretical band structure model was validated by comparing the energy of the no-phonon peak calculated by the 6 + 2-bandk·pmethod with experimental PL data. Close agreement between theoretical calculations and experimental data was obtained.

A Systematic Cathode Study-Activation of a Thermionic Cathode, and Measuring Cesium Evaporation from a Dispenser Photocathode

DTIC Science & Technology

2010-06-01

QCM Quartz Crystal Deposition Monitor SEM Scanning Electron Microscope SRF Superconducting Radio Frequency T Torr Ti Titanium UHV Ultra...High Vacuum ( ᝺-7 Torr) UM University of Maryland QCM Quartz Crystal Deposition Monitor V Volt VAC Voltage-Alternating Current xvii...event. The two originally had problems with their tungsten filaments crystallizing and breaking. Being experimentalists, they added thorium in an

Three-dimensional fine structure of the organization of microtubules in neurite varicosities by ultra-high voltage electron microscope tomography.

PubMed

Nishida, Tomoki; Yoshimura, Ryoichi; Endo, Yasuhisa

2017-09-01

Neurite varicosities are highly specialized compartments that are involved in neurotransmitter/ neuromodulator release and provide a physiological platform for neural functions. However, it remains unclear how microtubule organization contributes to the form of varicosity. Here, we examine the three-dimensional structure of microtubules in varicosities of a differentiated PC12 neural cell line using ultra-high voltage electron microscope tomography. Three-dimensional imaging showed that a part of the varicosities contained an accumulation of organelles that were separated from parallel microtubule arrays. Further detailed analysis using serial sections and whole-mount tomography revealed microtubules running in a spindle shape of swelling in some other types of varicosities. These electron tomographic results showed that the structural diversity and heterogeneity of microtubule organization supported the form of varicosities, suggesting that a different distribution pattern of microtubules in varicosities is crucial to the regulation of varicosities development.

Structural evolution of nanoporous ultra-low k dielectrics under voltage stress

NASA Astrophysics Data System (ADS)

Raja, Archana; Shaw, Thomas; Grill, Alfred; Laibowitz, Robert; Heinz, Tony

2013-03-01

High speed interconnects in advanced integrated circuits require ultra-low-k dielectrics. Reduction of the dielectric constant is achieved via incorporation of nanopores in structures containing silicon, carbon, oxygen and hydrogen (SiCOH). We study nanoporous SiCOH films of k=2.5 and thicknesses of 40 - 400 nm. Leakage currents develop in the films under long-term voltage stress, eventually leading to breakdown and chip failure. Previous work* has shown the build-up of trap states as dielectric breakdown progresses. Using FTIR spectroscopy we have tracked the reorganization of the bonds in the SiCOH networks induced by voltage stress. Our results indicate that the cleavage of the Si-C and SiC-O bonds contribute toward increase in the density of bulk trapping states as breakdown is approached. AC conductance and capacitance measurements have also been carried out to describe interfacial and bulk traps and mechanisms. Comparison of breakdown properties of films with differing carbon content will also be presented to further delineate the role of carbon. *Atkin, J.M.; Shaw, T.M.; Liniger, E.; Laibowitz, R.B.; Heinz, T.F. Reliability Physics Symposium (IRPS), 2012 IEEE International Supported by the Semiconductor Research Corporation

Development and Application of a Wireless Sensor for Space Charge Density Measurement in an Ultra-High-Voltage, Direct-Current Environment.

PubMed

Xin, Encheng; Ju, Yong; Yuan, Haiwen

2016-10-20

A space charge density wireless measurement system based on the idea of distributed measurement is proposed for collecting and monitoring the space charge density in an ultra-high-voltage direct-current (UHVDC) environment. The proposed system architecture is composed of a number of wireless nodes connected with space charge density sensors and a base station. The space charge density sensor based on atmospheric ion counter method is elaborated and developed, and the ARM microprocessor and Zigbee radio frequency module are applied. The wireless network communication quality and the relationship between energy consumption and transmission distance in the complicated electromagnetic environment is tested. Based on the experimental results, the proposed measurement system demonstrates that it can adapt to the complex electromagnetic environment under the UHVDC transmission lines and can accurately measure the space charge density.

Substrate effects in high gain, low operating voltage SnSe2 photoconductor

NASA Astrophysics Data System (ADS)

Krishna, Murali; Kallatt, Sangeeth; Majumdar, Kausik

2018-01-01

High gain photoconductive devices find wide spread applications in low intensity light detection. Ultra-thin layered materials have recently drawn a lot of attention from researchers in this regard. However, in general, a large operating voltage is required to obtain large responsivity in these devices. In addition, the characteristics are often confounded by substrate induced trap effects. Here we report multi-layer SnSe2 based photoconductive devices using two different structures: (1) SiO2 substrate supported inter-digitated electrode (IDE), and (2) suspended channel. The IDE device exhibits a responsivity of ≈ {10}3 A W-1 and ≈ 8.66× {10}4 A W-1 at operating voltages of 1 mV and 100 mV, respectively—a superior low voltage performance over existing literature on planar 2D structures. However, the responsivity reduces by more than two orders of magnitude, while the transient response improves for the suspended device—providing insights into the critical role played by the channel-substrate interface in the gain mechanism. The results, on one hand, are promising for highly sensitive photoconductive applications consuming ultra-low power, and on the other hand, show a generic methodology that could be applied to other layered material based photoconductive devices as well for extracting the intrinsic behavior.

Ultra High Voltage Propellant Isolators and Insulators for JIMO Ion Thrusters

NASA Technical Reports Server (NTRS)

Banks, Bruce A.; Gaier, James R.; Hung, Ching-Cheh; Walters, Patty A.; Sechkar, Ed; Panko, Scott; Kamiotis, Christina A.

2004-01-01

Within NASA's Project Prometheus, high specific impulse ion thrusters for electric propulsion of spacecraft for the proposed Jupiter Icy Moon Orbiter (JIMO) mission to three of Jupiter's moons: Callisto, Ganymede and Europa will require high voltage operation to meet mission propulsion. The anticipated approx.6,500 volt net ion energy will require electrical insulation and propellant isolation which must exceed that used successfully by the NASA Solar Electric Propulsion Technology Readiness (NSTAR) Deep Space 1 mission thruster by a factor of approx.6. Xenon propellant isolator prototypes that operate at near one atmosphere and prototypes that operate at low pressures (<100 Torr) have been designed and are being tested for suitability to the JIMO mission requirements. Propellant isolators must be durable to Paschen breakdown, sputter contamination, high temperature, and high voltage while operating for factors longer duration than for the Deep Space 1 Mission. Insulators used to mount the thrusters as well as those needed to support the ion optics have also been designed and are under evaluation. Isolator and insulator concepts, design issues, design guidelines, fabrication considerations and performance issues are presented. The objective of the investigation was to identify candidate isolators and insulators that are sufficiently robust to perform durably and reliably during the proposed JIMO mission.

High-Voltage Clock Driver for Photon-Counting CCD Characterization

NASA Technical Reports Server (NTRS)

Baker, Robert

2013-01-01

A document discusses the CCD97 from e2v technologies as it is being evaluated at Goddard Space Flight Center's Detector Characterization Laboratory (DCL) for possible use in ultra-low background noise space astronomy applications, such as Terrestrial Planet Finder Coronagraph (TPF-C). The CCD97 includes a photoncounting mode where the equivalent output noise is less than one electron. Use of this mode requires a clock signal at a voltage level greater than the level achievable by the existing CCD (charge-coupled-device) electronics. A high-voltage waveform generator has been developed in code 660/601 to support the CCD97 evaluation. The unit generates required clock waveforms at voltage levels from -20 to +50 V. It deals with standard and arbitrary waveforms and supports pixel rates from 50 to 500 kHz. The system is designed to interface with existing Leach CCD electronics.

"Un-annealed and Annealed Pd Ultra-Thin Film on SiC Characterized by Scanning Probe Microscopy and X-ray Photoelectron Spectroscopy"

NASA Technical Reports Server (NTRS)

Lu, W. J.; Shi, D. T.; Elshot, K.; Bryant, E.; Lafate, K.; Chen, H.; Burger, A.; Collins, W. E.

1998-01-01

Pd/SiC has been used as a hydrogen and a hydrocarbon gas sensor operated at high temperature. UHV (Ultra High Vacuum)-Scanning Tunneling Microscopy (STM), Atomic Force Microscopy (AFM) and X-ray Photoelectron Spectroscopy (XPS) techniques were applied to study the relationship between the morphology and chemical compositions for Pd ultra-thin films on SiC (less than 30 angstroms) at different annealing temperatures. Pd ultra-thin film on 6H-SiC was prepared by the RF sputtering method. The morphology from UHV-STM and AFM shows that the Pd thin film was well deposited on SiC substrate, and the Pd was partially aggregated to round shaped participates at an annealing temperature of 300 C. At 400 C, the amount of surface participates decreases, and some strap shape participates appear. From XPS, Pd2Si was formed on the surface after annealing at 300 C, and all Pd reacted with SiC to form Pd2Si after annealing at 400 C. The intensity of the XPS Pd peak decreases enormously at 400 C. The Pd film diffused into SiC, and the Schottky barrier height has almost no changes. The work shows the Pd sicilides/SiC have the same electronic properties with Pd/SiC, and explains why the Pd/SiC sensor still responds to hydrogen at high operating temperatures.

Alumina-supported sub-nanometer Pt 10 clusters: Amorphization and role of the support material in a highly active CO oxidation catalyst

DOE PAGES

Yin, Chunrong; Negreiros, Fabio R.; Barcaro, Giovanni; ...

2017-02-03

Catalytic CO oxidation is unveiled on size-selected Pt 10 clusters deposited on two very different ultrathin (≈0.5–0.7 nm thick) alumina films: (i) a highly ordered alumina obtained under ultra-high vacuum (UHV) by oxidation of the NiAl(110) surface and (ii) amorphous alumina obtained by atomic layer deposition (ALD) on a silicon chip that is a close model of real-world supports. Notably, when exposed to realistic reaction conditions, the Pt 10/UHV-alumina system undergoes a morphological transition in both the clusters and the substrate, and becomes closely akin to Pt 10/ALD-alumina, thus reconciling UHV-type surface-science and real-world experiments. The Pt 10 clusters, thoroughlymore » characterized via combined experimental techniques and theoretical analysis, exhibit among the highest CO oxidation activity per Pt atom reported for CO oxidation catalysts, due to the interplay of ultra-small size and support effects. Lastly, a coherent interdisciplinary picture then emerges for this catalytic system.« less

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

Posch, J.

Systems and philosophies perceived on a grand scale, encompassing new ideas, are often characterized as a dream. But in fact, such dreams often lead to the first step to fruitful development. This article is based on a preliminary study of the existing electrical high-tension networks of Western Europe, Eastern Europe and the Soviet Union - which, as explained herein, may be merged into a multinational energy supply system. Such a system would constitute a completely interconnected Eurasian Power Grid. The idea of a Eurasian super grid, spanning from the Atlantic to the Ural and Siberia, is not new. Various studiesmore » have been conducted by both western Europe and the Soviet Union on this topic. Our world is currently in an era of extra high voltage (EHV) and ultra high voltage (UHV) electrical systems. This translates into existing UHV lines of 1150 kV which have already been proven in successful operation. Such UHV systems are capable of transmitting thousands of megawatts over a distance of a 1000 miles. Furthermore, national boundaries are not more a hindrance than the challenge of interconnecting complete networks into an overall synchronized working system with load exchange capabilities in all directions.« less

Ultra-low voltage electrowetting using graphite surfaces.

PubMed

Lomax, Deborah J; Kant, Pallav; Williams, Aled T; Patten, Hollie V; Zou, Yuqin; Juel, Anne; Dryfe, Robert A W

2016-10-26

The control of wetting behaviour underpins a variety of important applications from lubrication to microdroplet manipulation. Electrowetting is a powerful method to achieve external wetting control, by exploiting the potential-dependence of the liquid contact angle with respect to a solid substrate. Addition of a dielectric film to the surface of the substrate, which insulates the electrode from the liquid thereby suppressing electrolysis, has led to technological advances such as variable focal-length liquid lenses, electronic paper and the actuation of droplets in lab-on-a-chip devices. The presence of the dielectric, however, necessitates the use of large bias voltages (frequently in the 10-100 V range). Here we describe a simple, dielectric-free approach to electrowetting using the basal plane of graphite as the conducting substrate: unprecedented changes in contact angle for ultra-low voltages are seen below the electrolysis threshold (50° with 1 V for a droplet in air, and 100° with 1.5 V for a droplet immersed in hexadecane), which are shown to be reproducible, stable over 100 s of cycles and free of hysteresis. Our results dispel conventional wisdom that reversible, hysteresis-free electrowetting can only be achieved on solid substrates with the use of a dielectric. This work paves the way for the development of a new generation of efficient electrowetting devices using advanced materials such as graphene and monolayer MoS 2 .

Development and Application of a Wireless Sensor for Space Charge Density Measurement in an Ultra-High-Voltage, Direct-Current Environment

PubMed Central

Xin, Encheng; Ju, Yong; Yuan, Haiwen

2016-01-01

A space charge density wireless measurement system based on the idea of distributed measurement is proposed for collecting and monitoring the space charge density in an ultra-high-voltage direct-current (UHVDC) environment. The proposed system architecture is composed of a number of wireless nodes connected with space charge density sensors and a base station. The space charge density sensor based on atmospheric ion counter method is elaborated and developed, and the ARM microprocessor and Zigbee radio frequency module are applied. The wireless network communication quality and the relationship between energy consumption and transmission distance in the complicated electromagnetic environment is tested. Based on the experimental results, the proposed measurement system demonstrates that it can adapt to the complex electromagnetic environment under the UHVDC transmission lines and can accurately measure the space charge density. PMID:27775627

High performance Si nanowire field-effect-transistors based on a CMOS inverter with tunable threshold voltage.

PubMed

Van, Ngoc Huynh; Lee, Jae-Hyun; Sohn, Jung Inn; Cha, Seung Nam; Whang, Dongmok; Kim, Jong Min; Kang, Dae Joon

2014-05-21

We successfully fabricated nanowire-based complementary metal-oxide semiconductor (NWCMOS) inverter devices by utilizing n- and p-type Si nanowire field-effect-transistors (NWFETs) via a low-temperature fabrication processing technique. We demonstrate that NWCMOS inverter devices can be operated at less than 1 V, a significantly lower voltage than that of typical thin-film based complementary metal-oxide semiconductor (CMOS) inverter devices. This low-voltage operation was accomplished by controlling the threshold voltage of the n-type Si NWFETs through effective management of the nanowire (NW) doping concentration, while realizing high voltage gain (>10) and ultra-low static power dissipation (≤3 pW) for high-performance digital inverter devices. This result offers a viable means of fabricating high-performance, low-operation voltage, and high-density digital logic circuits using a low-temperature fabrication processing technique suitable for next-generation flexible electronics.

A non-inactivating high-voltage-activated two-pore Na+ channel that supports ultra-long action potentials and membrane bistability

NASA Astrophysics Data System (ADS)

Cang, Chunlei; Aranda, Kimberly; Ren, Dejian

2014-09-01

Action potentials (APs) are fundamental cellular electrical signals. The genesis of short APs lasting milliseconds is well understood. Ultra-long APs (ulAPs) lasting seconds to minutes also occur in eukaryotic organisms, but their biological functions and mechanisms of generation are largely unknown. Here, we identify TPC3, a previously uncharacterized member of the two-pore channel protein family, as a new voltage-gated Na+ channel (NaV) that generates ulAPs, and that establishes membrane potential bistability. Unlike the rapidly inactivating NaVs that generate short APs in neurons, TPC3 has a high activation threshold, activates slowly and does not inactivate—three properties that help generate long-lasting APs and guard the membrane against unintended perturbation. In amphibian oocytes, TPC3 forms a channel similar to channels induced by depolarization and sperm entry into eggs. TPC3 homologues are present in plants and animals, and they may be important for cellular processes and behaviours associated with prolonged membrane depolarization.

Energy compression of nanosecond high-voltage pulses based on two-stage hybrid scheme

NASA Astrophysics Data System (ADS)

Ulmaskulov, M. R.; Mesyats, G. A.; Sadykova, A. G.; Sharypov, K. A.; Shpak, V. G.; Shunailov, S. A.; Yalandin, M. I.

2017-04-01

Test results of high-voltage subnanosecond pulse generator with a hybrid, two-stage energy compression scheme are presented. After the first compression section with a gas discharger, a ferrite-filled gyromagnetic nonlinear transmitting line is used. The offered technical solution makes it possible to increase the voltage pulse amplitude from -185 kV to -325 kV, with a 2-ns pulse rise time minimized down to ˜180 ps. For the small output voltage amplitude of -240 kV, the shortest pulse front of ˜85 ps was obtained. The generator with maximum amplitude was utilized to form an ultra-short flow of runaway electrons in air-filled discharge gap with particles' energy approaching to 700 keV.

Study on Construction Technology Standardization of Primary Guide Rope Laying by Multi-rotor Aircraft in Stringing Construction of Transmission Line

NASA Astrophysics Data System (ADS)

Liu, Chen; Tang, Guang-Rui; Jiang, Ming; Dong, Yu-Ming

2017-09-01

According to the practical situation of stringing construction for Ultra High Voltage (UHV) overhead transmission line, construction technology standardization of primary guide rope laying by multi-rotor aircraft is studied. This paper mainly focuses on the construction preparation, test flight and technology of laying primary guide rope. The summary of the construction technology standardization of primary guide rope laying by multi-rotor aircraft in stringing construction are useful in further guiding practical construction of transmission line.

Design and performance of an ultra-high vacuum spin-polarized scanning tunneling microscope operating at 30 mK and in a vector magnetic field

NASA Astrophysics Data System (ADS)

von Allwörden, Henning; Eich, Andreas; Knol, Elze J.; Hermenau, Jan; Sonntag, Andreas; Gerritsen, Jan W.; Wegner, Daniel; Khajetoorians, Alexander A.

2018-03-01

We describe the design and performance of a scanning tunneling microscope (STM) that operates at a base temperature of 30 mK in a vector magnetic field. The cryogenics is based on an ultra-high vacuum (UHV) top-loading wet dilution refrigerator that contains a vector magnet allowing for fields up to 9 T perpendicular and 4 T parallel to the sample. The STM is placed in a multi-chamber UHV system, which allows in situ preparation and exchange of samples and tips. The entire system rests on a 150-ton concrete block suspended by pneumatic isolators, which is housed in an acoustically isolated and electromagnetically shielded laboratory optimized for extremely low noise scanning probe measurements. We demonstrate the overall performance by illustrating atomic resolution and quasiparticle interference imaging and detail the vibrational noise of both the laboratory and microscope. We also determine the electron temperature via measurement of the superconducting gap of Re(0001) and illustrate magnetic field-dependent measurements of the spin excitations of individual Fe atoms on Pt(111). Finally, we demonstrate spin resolution by imaging the magnetic structure of the Fe double layer on W(110).

Design and performance of an ultra-high vacuum spin-polarized scanning tunneling microscope operating at 30 mK and in a vector magnetic field.

PubMed

von Allwörden, Henning; Eich, Andreas; Knol, Elze J; Hermenau, Jan; Sonntag, Andreas; Gerritsen, Jan W; Wegner, Daniel; Khajetoorians, Alexander A

2018-03-01

We describe the design and performance of a scanning tunneling microscope (STM) that operates at a base temperature of 30 mK in a vector magnetic field. The cryogenics is based on an ultra-high vacuum (UHV) top-loading wet dilution refrigerator that contains a vector magnet allowing for fields up to 9 T perpendicular and 4 T parallel to the sample. The STM is placed in a multi-chamber UHV system, which allows in situ preparation and exchange of samples and tips. The entire system rests on a 150-ton concrete block suspended by pneumatic isolators, which is housed in an acoustically isolated and electromagnetically shielded laboratory optimized for extremely low noise scanning probe measurements. We demonstrate the overall performance by illustrating atomic resolution and quasiparticle interference imaging and detail the vibrational noise of both the laboratory and microscope. We also determine the electron temperature via measurement of the superconducting gap of Re(0001) and illustrate magnetic field-dependent measurements of the spin excitations of individual Fe atoms on Pt(111). Finally, we demonstrate spin resolution by imaging the magnetic structure of the Fe double layer on W(110).

UHV AFM based colloidal probe studies of adhesive properties of VAlN hard coatings

NASA Astrophysics Data System (ADS)

Wiesing, M.; de los Arcos, T.; Grundmeier, G.

2018-01-01

The adhesion of polystyrene (PS) on V0.27Al0.29N0.44 and the related influence of the oxidation states of both surfaces was investigated using X-Ray Photoelectron Spectroscopy (XPS) and Colloidal Force Spectroscopy (CFS) in Ultra-High Vacuum (UHV). Complementary, the intimate relation between the adhesion force, the chemical structure and surface polarizability was investigated by XPS valence band spectroscopy and the calculation of non-retarded Hamaker coefficients using Lifshitz theory based on optical data as derived from Reflection Electron Energy Loss Spectroscopy (REELS) spectra. The combined electron and force spectroscopic analysis of the interaction forces disclosed quantitatively the separation of the adhesion force in van der Waals and Lewis acid-base contributions. Further, the surface polarizability of VAlN was shown to be unaffected by oxygen incorporation due to the formation of an only gradually oxidized surface comprising a range of vanadium oxidation states. In contrast, the adhesion force analysis revealed additional Lewis acid-base interactions between the oxidized and non-oxidized VAlN surfaces and carboxyl groups present in the surface of PS after an oxidative oxygen beam treatment.

Low voltage to high voltage level shifter and related methods

NASA Technical Reports Server (NTRS)

Mentze, Erik J. (Inventor); Buck, Kevin M. (Inventor); Hess, Herbert L. (Inventor); Cox, David F. (Inventor)

2006-01-01

A shifter circuit comprises a high and low voltage buffer stages and an output buffer stage. The high voltage buffer stage comprises multiple transistors arranged in a transistor stack having a plurality of intermediate nodes connecting individual transistors along the stack. The transistor stack is connected between a voltage level being shifted to and an input voltage. An inverter of this stage comprises multiple inputs and an output. Inverter inputs are connected to a respective intermediate node of the transistor stack. The low voltage buffer stage has an input connected to the input voltage and an output, and is operably connected to the high voltage buffer stage. The low voltage buffer stage is connected between a voltage level being shifted away from and a lower voltage. The output buffer stage is driven by the outputs of the high voltage buffer stage inverter and the low voltage buffer stage.

HIGH VOLTAGE GENERATOR

DOEpatents

Zito, G.V.

1959-04-21

This patent relates to high voltage supply circuits adapted for providing operating voltages for GeigerMueller counter tubes, and is especially directed to an arrangement for maintaining uniform voltage under changing conditions of operation. In the usual power supply arrangement for counter tubes the counter voltage is taken from across the power supply output capacitor. If the count rate exceeds the current delivering capaciiy of the capacitor, the capacitor voltage will drop, decreasing the counter voltage. The present invention provides a multivibrator which has its output voltage controlled by a signal proportional to the counting rate. As the counting rate increases beyond the current delivering capacity of the capacitor, the rectified voltage output from the multivibrator is increased to maintain uniform counter voltage.

Dispensing of very low volumes of ultra high viscosity alginate gels: a new tool for encapsulation of adherent cells and rapid prototyping of scaffolds and implants.

PubMed

Gepp, Michael M; Ehrhart, Friederike; Shirley, Stephen G; Howitz, Steffen; Zimmermann, Heiko

2009-01-01

We present a tool for dispensing very low volumes (20 nL or more) of ultra high viscosity (UHV) medical-grade alginate hydrogels. It uses a modified piezo-driven micrometering valve, integrated into a versatile system that allows fast prototyping of encapsulation procedures and scaffold production. Valves show excellent dispensing properties for UHV alginate in concentrations of 0.4% and 0.7% and also for aqueous liquids. An optimized process flow provides excellent handling of biological samples under sterile conditions. This technique allows the encapsulation of adherent cells and structuring of substrates for biotechnology and regenerative medicine. A variety of cell lines showed at least 70% viability after encapsulation (including cell lines that are relevant in regenerative medicine like Hep G2), and time-lapse analysis revealed cells proliferating and showing limited motility under alginate spots. Cells show metabolic activity, gene product expression, and physiological function. Encapsulated cells have contact with the substrate and can exchange metabolites while being isolated from macromolecules in the environment. Contactless dispensing allows structuring of substrates with alginate, isolation and transfer of cell-alginate complexes, and the dispensing of biological active hydrogels like extracellular matrix-derived gels.

High-energy green supercapacitor driven by ionic liquid electrolytes as an ultra-high stable next-generation energy storage device

NASA Astrophysics Data System (ADS)

Thangavel, Ranjith; Kannan, Aravindaraj G.; Ponraj, Rubha; Thangavel, Vigneysh; Kim, Dong-Won; Lee, Yun-Sung

2018-04-01

Development of supercapacitors with high energy density and long cycle life using sustainable materials for next-generation applications is of paramount importance. The ongoing challenge is to elevate the energy density of supercapacitors on par with batteries, while upholding the power and cyclability. In addition, attaining such superior performance with green and sustainable bio-mass derived compounds is very crucial to address the rising environmental concerns. Herein, we demonstrate the use of watermelon rind, a bio-waste from watermelons, towards high energy, and ultra-stable high temperature green supercapacitors with a high-voltage ionic liquid electrolyte. Supercapacitors assembled with ultra-high surface area, hierarchically porous carbon exhibits a remarkable performance both at room temperature and at high temperature (60 °C) with maximum energy densities of ∼174 Wh kg-1 (25 °C), and 177 Wh kg-1 (60 °C) - based on active mass of both electrodes. Furthermore, an ultra-high specific power of ∼20 kW kg-1 along with an ultra-stable cycling performance with 90% retention over 150,000 cycles has been achieved even at 60 °C, outperforming supercapacitors assembled with other carbon based materials. These results demonstrate the potential to develop high-performing, green energy storage devices using eco-friendly materials for next generation electric vehicles and other advanced energy storage systems.

High power radiators of ultra-short electromagnetic quasi-unipolar pulses

NASA Astrophysics Data System (ADS)

Fedorov, V. M.; Ostashev, V. E.; Tarakanov, V. P.; Ul'yanov, A. V.

2017-05-01

Results of creation, operation, and diagnostics of the high power radiators for ultra-short length electromagnetic pulses (USEMPs) with a quasi-unipolar profile, which have been developed in our laboratory, are presented. The radiating module contains: the ultra-wideband (UWB) antenna array, the exciting high voltage pulse semiconductor generator (a pulser), the power source and the control unit. The principles of antenna array with a high efficiency aperture about 0.9 were developed using joint four TEM-horns with shielding electrodes in every TEM-horn. Sizes of the antenna apertures were (16-60) cm. The pulsers produced by “FID Technology” company had the following parameters: 50 Ohm connector impedance, unipolar pulses voltages (10-100) kV, the rise-time (0.04-0.15) ns, and the width (0.2-1) ns. The modules radiate the USEMPs of (0.1-10) GHz spectrum, their repetition rate is (1-100) kHz, and the effective potential is E*R = (20-400) kV, producing the peak E-field into the far-zone of R-distance. Parameters of the USEMP waves were measured by a calibrated sensor with the following characteristics: the sensitivity 0.32V/(kV/m), the rise-time 0.03 ns, the duration up to 7 ns. The measurements were in agreement with the simulation results, which were obtained using the 3-D code “KARAT”. The USEMP waves with amplitudes (1-10) kV/m and the pulse repetition rate (0.5-100) kHz were successfully used to examine various electronic devices for an electromagnetic immunity.

The design and implementation of on-line monitoring system for UHV compact shunt capacitors

NASA Astrophysics Data System (ADS)

Tao, Weiliang; Ni, Xuefeng; Lin, Hao; Jiang, Shengbao

2017-08-01

Because of the large capacity and compact structure of the UHV compact shunt capacitor, it is difficult to take effective measures to detect and prevent the faults. If the fault capacitor fails to take timely maintenance, it will pose a threat to the safe operation of the system and the life safety of the maintenance personnel. The development of UHV compact shunt capacitor on-line monitoring system can detect and record the on-line operation information of UHV compact shunt capacitors, analyze and evaluate the early fault warning signs, find out the fault capacitor or the capacitor with fault symptom, to ensure safe and reliable operation of the system.

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.

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.

Calibration of Voltage Transformers and High- Voltage Capacitors at NIST

PubMed Central

Anderson, William E.

1989-01-01

The National Institute of Standards and Technology (NIST) calibration service for voltage transformers and high-voltage capacitors is described. The service for voltage transformers provides measurements of ratio correction factors and phase angles at primary voltages up to 170 kV and secondary voltages as low as 10 V at 60 Hz. Calibrations at frequencies from 50–400 Hz are available over a more limited voltage range. The service for high-voltage capacitors provides measurements of capacitance and dissipation factor at applied voltages ranging from 100 V to 170 kV at 60 Hz depending on the nominal capacitance. Calibrations over a reduced voltage range at other frequencies are also available. As in the case with voltage transformers, these voltage constraints are determined by the facilities at NIST. PMID:28053409

High voltage variable diameter insulator

DOEpatents

Vanacek, D.L.; Pike, C.D.

1982-07-13

A high voltage feedthrough assembly having a tubular insulator extending between the ground plane ring and the high voltage ring. The insulator is made of Pyrex and decreases in diameter from the ground plane ring to the high voltage ring, producing equipotential lines almost perpendicular to the wall of the insulator to optimize the voltage-holding capability of the feedthrough assembly.

High voltage variable diameter insulator

DOEpatents

Vanecek, David L.; Pike, Chester D.

1984-01-01

A high voltage feedthrough assembly (10) having a tubular insulator (15) extending between the ground plane ring (16) and the high voltage ring (30). The insulator (15) is made of Pyrex and decreases in diameter from the ground plane ring (16) to the high voltage ring (30), producing equipotential lines almost perpendicular to the wall (27) of the insulator (15) to optimize the voltage-holding capability of the feedthrough assembly (10).

Calibration of ultra-high frequency (UHF) partial discharge sensors using FDTD method

NASA Astrophysics Data System (ADS)

Ishak, Asnor Mazuan; Ishak, Mohd Taufiq

2018-02-01

Ultra-high frequency (UHF) partial discharge sensors are widely used for conditioning monitoring and defect location in insulation system of high voltage equipment. Designing sensors for specific applications often requires an iterative process of manufacturing, testing and mechanical modifications. This paper demonstrates the use of finite-difference time-domain (FDTD) technique as a tool to predict the frequency response of UHF PD sensors. Using this approach, the design process can be simplified and parametric studies can be conducted in order to assess the influence of component dimensions and material properties on the sensor response. The modelling approach is validated using gigahertz transverse electromagnetic (GTEM) calibration system. The use of a transient excitation source is particularly suitable for modeling using FDTD, which is able to simulate the step response output voltage of the sensor from which the frequency response is obtained using the same post-processing applied to the physical measurement.

High voltage pulse generator

DOEpatents

Fasching, George E.

1977-03-08

An improved high-voltage pulse generator has been provided which is especially useful in ultrasonic testing of rock core samples. An N number of capacitors are charged in parallel to V volts and at the proper instance are coupled in series to produce a high-voltage pulse of N times V volts. Rapid switching of the capacitors from the paralleled charging configuration to the series discharging configuration is accomplished by using silicon-controlled rectifiers which are chain self-triggered following the initial triggering of a first one of the rectifiers connected between the first and second of the plurality of charging capacitors. A timing and triggering circuit is provided to properly synchronize triggering pulses to the first SCR at a time when the charging voltage is not being applied to the parallel-connected charging capacitors. Alternate circuits are provided for controlling the application of the charging voltage from a charging circuit to be applied to the parallel capacitors which provides a selection of at least two different intervals in which the charging voltage is turned "off" to allow the SCR's connecting the capacitors in series to turn "off" before recharging begins. The high-voltage pulse-generating circuit including the N capacitors and corresponding SCR's which connect the capacitors in series when triggered "on" further includes diodes and series-connected inductors between the parallel-connected charging capacitors which allow sufficiently fast charging of the capacitors for a high pulse repetition rate and yet allow considerable control of the decay time of the high-voltage pulses from the pulse-generating circuit.

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-performance radial AMTEC cell design for ultra-high-power solar AMTEC systems

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

Hendricks, T.J.; Huang, C.

1999-07-01

Alkali Metal Thermal to Electric Conversion (AMTEC) technology is rapidly maturing for potential application in ultra-high-power solar AMTEC systems required by potential future US Air Force (USAF) spacecraft missions in medium-earth and geosynchronous orbits (MEO and GEO). Solar thermal AMTEC power systems potentially have several important advantages over current solar photovoltaic power systems in ultra-high-power spacecraft applications for USAF MEO and GEO missions. This work presents key aspects of radial AMTEC cell design to achieve high cell performance in solar AMTEC systems delivering larger than 50 kW(e) to support high power USAF missions. These missions typically require AMTEC cell conversionmore » efficiency larger than 25%. A sophisticated design parameter methodology is described and demonstrated which establishes optimum design parameters in any radial cell design to satisfy high-power mission requirements. Specific relationships, which are distinct functions of cell temperatures and pressures, define critical dependencies between key cell design parameters, particularly the impact of parasitic thermal losses on Beta Alumina Solid Electrolyte (BASE) area requirements, voltage, number of BASE tubes, and system power production for both maximum power-per-BASE-area and optimum efficiency conditions. Finally, some high-level system tradeoffs are demonstrated using the design parameter methodology to establish high-power radial cell design requirements and philosophy. The discussion highlights how to incorporate this methodology with sophisticated SINDA/FLUINT AMTEC cell modeling capabilities to determine optimum radial AMTEC cell designs.« less

Performance analysis of microcomputer based differential protection of UHV lines under selective phase switching

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

Bhatti, A.A.

1990-04-01

This paper examines the effects of primary and secondary fault quantities as well s of mutual couplings of neighboring circuits on the sensitivity of operation and threshold settings of a microcomputer based differential protection of UHV lines under selective phase switching. Microcomputer based selective phase switching allows the disconnection of minimum number of phases involved in a fault and requires the autoreclosing of these phases immediately after the extinction of secondary arc. During a primary fault a heavy current contribution to the healthy phases tends to cause an unwanted tripping. Faulty phases physically disconnected constitute an isolated fault which beingmore » coupled to the system affects the current and voltage levels of the healthy phases still retained in the system and may cause an unwanted tripping. The microcomputer based differential protection, appears to have poor performance when applied to uncompensated lines employing selective pole switching.« less

Fast auto-acquisition tomography tilt series by using HD video camera in ultra-high voltage electron microscope.

PubMed

Nishi, Ryuji; Cao, Meng; Kanaji, Atsuko; Nishida, Tomoki; Yoshida, Kiyokazu; Isakozawa, Shigeto

2014-11-01

The ultra-high voltage electron microscope (UHVEM) H-3000 with the world highest acceleration voltage of 3 MV can observe remarkable three dimensional microstructures of microns-thick samples[1]. Acquiring a tilt series of electron tomography is laborious work and thus an automatic technique is highly desired. We proposed the Auto-Focus system using image Sharpness (AFS)[2,3] for UHVEM tomography tilt series acquisition. In the method, five images with different defocus values are firstly acquired and the image sharpness are calculated. The sharpness are then fitted to a quasi-Gaussian function to decide the best focus value[3]. Defocused images acquired by the slow scan CCD (SS-CCD) camera (Hitachi F486BK) are of high quality but one minute is taken for acquisition of five defocused images.In this study, we introduce a high-definition video camera (HD video camera; Hamamatsu Photonics K. K. C9721S) for fast acquisition of images[4]. It is an analog camera but the camera image is captured by a PC and the effective image resolution is 1280×1023 pixels. This resolution is lower than that of the SS-CCD camera of 4096×4096 pixels. However, the HD video camera captures one image for only 1/30 second. In exchange for the faster acquisition the S/N of images are low. To improve the S/N, 22 captured frames are integrated so that each image sharpness is enough to become lower fitting error. As countermeasure against low resolution, we selected a large defocus step, which is typically five times of the manual defocus step, to discriminate different defocused images.By using HD video camera for autofocus process, the time consumption for each autofocus procedure was reduced to about six seconds. It took one second for correction of an image position and the total correction time was seven seconds, which was shorter by one order than that using SS-CCD camera. When we used SS-CCD camera for final image capture, it took 30 seconds to record one tilt image. We can obtain a tilt

High-voltage, high-current, solid-state closing switch

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

Focia, Ronald Jeffrey

2017-08-22

A high-voltage, high-current, solid-state closing switch uses a field-effect transistor (e.g., a MOSFET) to trigger a high-voltage stack of thyristors. The switch can have a high hold-off voltage, high current carrying capacity, and high time-rate-of-change of current, di/dt. The fast closing switch can be used in pulsed power applications.

Magnetic Material Assessment of a Novel Ultra-High Step-Up Converter with Single Semiconductor Switch and Galvanic Isolation for Fuel-Cell Power System.

PubMed

Shen, Chih-Lung; Liou, Heng

2017-11-15

In this paper, a novel step-up converter is proposed, which has the particular features of single semiconductor switch, ultra-high conversion ratio, galvanic isolation, and easy control. Therefore, the proposed converter is suitable for the applications of fuel-cell power system. Coupled inductors and switched capacitors are incorporated in the converter to obtain an ultra-high voltage ratio that is much higher than that of a conventional high step-up converter. Even if the turns ratio of coupled inductor and duty ratio are only to be 1 and 0.5, respectively, the converter can readily achieve a voltage gain of up to 18. Owing to this outstanding performance, it can also be applied to any other low voltage source for voltage boosting. In the power stage, only one active switch is used to handle the converter operation. In addition, the leakage energy of the two couple inductors can be totally recycled without any snubber, which simplifies the control mechanism and improves the conversion efficiency. Magnetic material dominates the conversion performance of the converter. Different types of iron cores are discussed for the possibility to serve as a coupled inductor. A 200 W prototype with 400 V output voltage is built to validate the proposed converter. In measurement, it indicates that the highest efficiency can be up to 94%.

Magnetic Material Assessment of a Novel Ultra-High Step-Up Converter with Single Semiconductor Switch and Galvanic Isolation for Fuel-Cell Power System

PubMed Central

Shen, Chih-Lung; Liou, Heng

2017-01-01

In this paper, a novel step-up converter is proposed, which has the particular features of single semiconductor switch, ultra-high conversion ratio, galvanic isolation, and easy control. Therefore, the proposed converter is suitable for the applications of fuel-cell power system. Coupled inductors and switched capacitors are incorporated in the converter to obtain an ultra-high voltage ratio that is much higher than that of a conventional high step-up converter. Even if the turns ratio of coupled inductor and duty ratio are only to be 1 and 0.5, respectively, the converter can readily achieve a voltage gain of up to 18. Owing to this outstanding performance, it can also be applied to any other low voltage source for voltage boosting. In the power stage, only one active switch is used to handle the converter operation. In addition, the leakage energy of the two couple inductors can be totally recycled without any snubber, which simplifies the control mechanism and improves the conversion efficiency. Magnetic material dominates the conversion performance of the converter. Different types of iron cores are discussed for the possibility to serve as a coupled inductor. A 200 W prototype with 400 V output voltage is built to validate the proposed converter. In measurement, it indicates that the highest efficiency can be up to 94%. PMID:29140282

High Voltage SPT Performance

NASA Technical Reports Server (NTRS)

Manzella, David; Jacobson, David; Jankovsky, Robert

2001-01-01

A 2.3 kW stationary plasma thruster designed to operate at high voltage was tested at discharge voltages between 300 and 1250 V. Discharge specific impulses between 1600 and 3700 sec were demonstrated with thrust between 40 and 145 mN. Test data indicated that discharge voltage can be optimized for maximum discharge efficiency. The optimum discharge voltage was between 500 and 700 V for the various anode mass flow rates considered. The effect of operating voltage on optimal magnet field strength was investigated. The effect of cathode flow rate on thruster efficiency was considered for an 800 V discharge.

High voltage power supply

NASA Technical Reports Server (NTRS)

Ruitberg, A. P.; Young, K. M. (Inventor)

1985-01-01

A high voltage power supply is formed by three discrete circuits energized by a battery to provide a plurality of concurrent output signals floating at a high output voltage on the order of several tens of kilovolts. In the first two circuits, the regulator stages are pulse width modulated and include adjustable ressistances for varying the duty cycles of pulse trains provided to corresponding oscillator stages while the third regulator stage includes an adjustable resistance for varying the amplitude of a steady signal provided to a third oscillator stage. In the first circuit, the oscillator, formed by a constant current drive network and a tuned resonant network included a step up transformer, is coupled to a second step up transformer which, in turn, supplies an amplified sinusoidal signal to a parallel pair of complementary poled rectifying, voltage multiplier stages to generate the high output voltage.

High voltage DC power supply

DOEpatents

Droege, T.F.

1989-12-19

A high voltage DC power supply having a first series resistor at the output for limiting current in the event of a short-circuited output, a second series resistor for sensing the magnitude of output current, and a voltage divider circuit for providing a source of feedback voltage for use in voltage regulation is disclosed. The voltage divider circuit is coupled to the second series resistor so as to compensate the feedback voltage for a voltage drop across the first series resistor. The power supply also includes a pulse-width modulated control circuit, having dual clock signals, which is responsive to both the feedback voltage and a command voltage, and also includes voltage and current measuring circuits responsive to the feedback voltage and the voltage developed across the second series resistor respectively. 7 figs.

High voltage DC power supply

DOEpatents

Droege, Thomas F.

1989-01-01

A high voltage DC power supply having a first series resistor at the output for limiting current in the event of a short-circuited output, a second series resistor for sensing the magnitude of output current, and a voltage divider circuit for providing a source of feedback voltage for use in voltage regulation is disclosed. The voltage divider circuit is coupled to the second series resistor so as to compensate the feedback voltage for a voltage drop across the first series resistor. The power supply also includes a pulse-width modulated control circuit, having dual clock signals, which is responsive to both the feedback voltage and a command voltage, and also includes voltage and current measuring circuits responsive to the feedback voltage and the voltage developed across the second series resistor respectively.

High voltage coaxial switch

DOEpatents

Rink, J.P.

1983-07-19

A coaxial high voltage, high current switch having a solid cylindrical cold cathode coaxially surrounded by a thin hollow cylindrical inner electrode and a larger hollow cylindrical outer electrode. A high voltage trigger between the cathode and the inner electrode causes electrons to be emitted from the cathode and flow to the inner electrode preferably through a vacuum. Some of the electrons penetrate the inner electrode and cause a volumetric discharge in the gas (which may be merely air) between the inner and outer electrodes. The discharge provides a low impedance path between a high voltage charge placed on the outer electrode and a load (which may be a high power laser) coupled to the inner electrode. For high repetition rate the gas between the inner and outer electrodes may be continuously exchanged or refreshed under pressure. 3 figs.

High voltage coaxial switch

DOEpatents

Rink, John P.

1983-07-19

A coaxial high voltage, high current switch having a solid cylindrical cold cathode coaxially surrounded by a thin hollow cylindrical inner electrode and a larger hollow cylindrical outer electrode. A high voltage trigger between the cathode and the inner electrode causes electrons to be emitted from the cathode and flow to the inner electrode preferably through a vacuum. Some of the electrons penetrate the inner electrode and cause a volumetric discharge in the gas (which may be merely air) between the inner and outer electrodes. The discharge provides a low impedance path between a high voltage charge placed on the outer electrode and a load (which may be a high power laser) coupled to the inner electrode. For high repetition rate the gas between the inner and outer electrodes may be continuously exchanged or refreshed under pressure.

Low power, scalable multichannel high voltage controller

DOEpatents

Stamps, James Frederick [Livermore, CA; Crocker, Robert Ward [Fremont, CA; Yee, Daniel Dadwa [Dublin, CA; Dils, David Wright [Fort Worth, TX

2006-03-14

A low voltage control circuit is provided for individually controlling high voltage power provided over bus lines to a multitude of interconnected loads. An example of a load is a drive for capillary channels in a microfluidic system. Control is distributed from a central high voltage circuit, rather than using a number of large expensive central high voltage circuits to enable reducing circuit size and cost. Voltage is distributed to each individual load and controlled using a number of high voltage controller channel switches connected to high voltage bus lines. The channel switches each include complementary pull up and pull down photo isolator relays with photo isolator switching controlled from the central high voltage circuit to provide a desired bus line voltage. Switching of the photo isolator relays is further controlled in each channel switch using feedback from a resistor divider circuit to maintain the bus voltage swing within desired limits. Current sensing is provided using a switched resistive load in each channel switch, with switching of the resistive loads controlled from the central high voltage circuit.

Low power, scalable multichannel high voltage controller

DOEpatents

Stamps, James Frederick [Livermore, CA; Crocker, Robert Ward [Fremont, CA; Yee, Daniel Dadwa [Dublin, CA; Dils, David Wright [Fort Worth, TX

2008-03-25

A low voltage control circuit is provided for individually controlling high voltage power provided over bus lines to a multitude of interconnected loads. An example of a load is a drive for capillary channels in a microfluidic system. Control is distributed from a central high voltage circuit, rather than using a number of large expensive central high voltage circuits to enable reducing circuit size and cost. Voltage is distributed to each individual load and controlled using a number of high voltage controller channel switches connected to high voltage bus lines. The channel switches each include complementary pull up and pull down photo isolator relays with photo isolator switching controlled from the central high voltage circuit to provide a desired bus line voltage. Switching of the photo isolator relays is further controlled in each channel switch using feedback from a resistor divider circuit to maintain the bus voltage swing within desired limits. Current sensing is provided using a switched resistive load in each channel switch, with switching of the resistive loads controlled from the central high voltage circuit.

Polymer/metal oxide hybrid dielectrics for low voltage field-effect transistors with solution-processed, high-mobility semiconductors

NASA Astrophysics Data System (ADS)

Held, Martin; Schießl, Stefan P.; Miehler, Dominik; Gannott, Florentina; Zaumseil, Jana

2015-08-01

Transistors for future flexible organic light-emitting diode (OLED) display backplanes should operate at low voltages and be able to sustain high currents over long times without degradation. Hence, high capacitance dielectrics with low surface trap densities are required that are compatible with solution-processable high-mobility semiconductors. Here, we combine poly(methyl methacrylate) (PMMA) and atomic layer deposition hafnium oxide (HfOx) into a bilayer hybrid dielectric for field-effect transistors with a donor-acceptor polymer (DPPT-TT) or single-walled carbon nanotubes (SWNTs) as the semiconductor and demonstrate substantially improved device performances for both. The ultra-thin PMMA layer ensures a low density of trap states at the semiconductor-dielectric interface while the metal oxide layer provides high capacitance, low gate leakage and superior barrier properties. Transistors with these thin (≤70 nm), high capacitance (100-300 nF/cm2) hybrid dielectrics enable low operating voltages (<5 V), balanced charge carrier mobilities and low threshold voltages. Moreover, the hybrid layers substantially improve the bias stress stability of the transistors compared to those with pure PMMA and HfOx dielectrics.

High voltage solar array experiments

NASA Technical Reports Server (NTRS)

Kennerud, K. L.

1974-01-01

The interaction between the components of a high voltage solar array and a simulated space plasma is studied to obtain data for the design of a high voltage solar array capable of 15kW at 2 to 16kV. Testing was conducted in a vacuum chamber 1.5-m long by 1.5-m diameter having a plasma source which simulated the plasma conditions existing in earth orbit between 400 nautical miles and synchronous altitude. Test samples included solar array segments pinholes in insulation covering high voltage electrodes, and plain dielectric samples. Quantitative data are presented in the areas of plasma power losses, plasma and high voltage induced damage, and dielectric properties. Limitations of the investigation are described.

Development of the Fast Scintillation Detector with Programmable High Voltage Adjustment Suitable for Moessbauer Spectroscopy

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

Prochazka, R.; Frydrych, J.; Pechousek, J.

2010-07-13

This work is focused on a development of a compact fast scintillation detector suitable for Moessbauer spectroscopy (low energy X-ray/{gamma}-ray detection) where high counting rates are inevitable. Optimization of this part was necessary for a reliable function, better time resolution and to avoid a detector pulses pile-up effect. The pile-up effect decreases the measurement performance, significantly depends on the source activity and also on the pulse duration. Our new detection unit includes a fast scintillation crystal YAP:Ce, an R6095 photomultiplier tube, a high voltage power supply socket C9028-01 assembly, an AD5252 digital potentiometer with an I2C interface and an AD8000more » ultra fast operation preamplifier. The main advantages of this solution lie in a short pulse duration (less than 200 ns), stable operation for high activities, programmable gain of the high voltage supply and compact design in the aluminum housing.« less

Characterization of the CEBAF 100 kV DC GaAs Photoelectron Gun Vacuum System

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

Stutzman, M L; Adderley, P; Brittian, J

A vacuum system with pressure in the low ultra-high vacuum (UHV) range is essential for long photocathode lifetimes in DC high voltage GaAs photoguns. A discrepancy between predicted and measured base pressure in the CEBAF photoguns motivated this study of outgassing rates of three 304 stainless steel chambers with different pretreatments and pump speed measurements of non-evaporable getter (NEG) pumps. Outgassing rates were measured using two independent techniques. Lower outgassing rates were achieved by electropolishing and vacuum firing the chamber. The second part of the paper describes NEG pump speed measurements as a function of pressure through the lower partmore » of the UHV range. Measured NEG pump speed is high at pressures above 5×10 -11 Torr, but may decrease at lower pressures depending on the interpretation of the data. The final section investigates the pump speed of a locally produced NEG coating applied to the vacuum chamber walls. These studies represent the first detailed vacuum measurements of CEBAF photogun vacuum chambers.« less

APPARATUS FOR REGULATING HIGH VOLTAGE

DOEpatents

Morrison, K.G.

1951-03-20

This patent describes a high-voltage regulator of the r-f type wherein the modulation of the r-f voltage is accomplished at a high level, resulting in good stabilization over a large range of load conditions.

High Voltage Insulation Technology

NASA Astrophysics Data System (ADS)

Scherb, V.; Rogalla, K.; Gollor, M.

2008-09-01

In preparation of new Electronic Power Conditioners (EPC's) for Travelling Wave Tub Amplifiers (TWTA's) on telecom satellites a study for the development of new high voltage insulation technology is performed. The initiative is mandatory to allow compact designs and to enable higher operating voltages. In a first task a market analysis was performed, comparing different materials with respect to their properties and processes. A hierarchy of selection criteria was established and finally five material candidates (4 Epoxy resins and 1 Polyurethane resin) were selected to be further investigated in the test program. Samples for the test program were designed to represent core elements of an EPC, the high voltage transformer and Printed Circuit Boards of the high voltage section. All five materials were assessed in the practical work flow of the potting process and electrical, mechanical, thermal and lifetime testing was performed. Although the lifetime tests results were overlayed by a larges scatter, finally two candidates have been identified for use in a subsequent qualification program. This activity forms part of element 5 of the ESA ARTES Programme.

A simple compact UHV and high magnetic field compatible inertial nanopositioner

NASA Astrophysics Data System (ADS)

Pang, Zongqiang; Li, Xiang; Xu, Lei; Rong, Zhou; Liu, Ruilan

2015-01-01

We present a novel simple piezoelectric nanopositioner which just has one piezoelectric scanner tube (PST) and one driving signal, using two short quartz rods and one BeCu spring which form a triangle to press the central shaft and can promise the nanopositioner's rigidity. Applying two pulse inverted voltage signals on the PST's outer and inner electrodes, respectively, according to the principle of piezoelectricity, the PST will elongate or contract suddenly while the central shaft will keep stationary for its inertance, so the central shaft will be sliding a distance relative to quartz rods and spring, and then withdraw the pulse voltages slowly, the central shaft will move upward or downward one step. The heavier of the central shaft, the better moving stability, so the nanopositioner has high output force. Due to its compactness and mechanical stability, it can be easily implanted into some extreme conditions, such as ultrahigh vacuum, ultralow temperature, and high magnetic field.

Effect of secondary electron emission on subnanosecond breakdown in high-voltage pulse discharge

NASA Astrophysics Data System (ADS)

Schweigert, I. V.; Alexandrov, A. L.; Gugin, P.; Lavrukhin, M.; Bokhan, P. A.; Zakrevsky, Dm E.

2017-11-01

The subnanosecond breakdown in open discharge may be applied for producing superfast high power switches. Such fast breakdown in high-voltage pulse discharge in helium was explored both in experiment and in kinetic simulations. The kinetic model of electron avalanche development was developed using PIC-MCC technique. The model simulates motion of electrons, ions and fast helium atoms, appearing due to ions scattering. It was shown that the mechanism responsible for ultra-fast breakdown development is the electron emission from cathode. The photoemission and emission by ions or fast atoms impact is the main reason of current growth at the early stage of breakdown, but at the final stage, when the voltage on discharge gap drops, the secondary electron emission (SEE) is responsible for subnanosecond time scale of current growth. It was also found that the characteristic time of the current growth τS depends on the SEE yield of the cathode material. Three types of cathode material (titanium, SiC, and CuAlMg-alloy) were tested. It is shown that in discharge with SiC and CuAlMg-alloy cathodes (which have enhanced SEE) the current can increase with a subnanosecond characteristic time as small as τS = 0.4 ns, for the pulse voltage amplitude of 5- 12 kV..

Uhv compatible chopper system

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

Voss, D.E.; Cohen, S.A.

1979-11-01

A time-of-flight system utilizing a novel mechanical chopper has been developed to measure the energy spectrum of neutral deuterium atoms emitted from a tokamak plasma. The chopper system consists of a motor, a magnetically levitated shaft, and a chopper disc. The 20 g disc is rigidly attached to a 159 g shaft assembly and the set is supported against gravity in vacuum by permanent magnets and a stabilizing servo system. All components are uhv compatible to avoid contamination to the tokamak and to the detector. The 25.4 cm OD, .005 cm thick, 301 stainless steel chopper disc has 24 .025more » cm wide slots photoetched at an 11.4 cm radius. An effective aperture time of .55 ..mu..s is achieved during typical steady state operation at 22,500 rpm with a vacuum pressure of 2 x 10/sup -8/ torr.« less

Fabrication of universal serial bus flash disk type microfluidic chip electrophoresis and application for protein analysis under ultra low voltage

PubMed Central

Cong, Hailin; Xu, Xiaodan; Yu, Bing; Liu, Huwei

2016-01-01

A simple and effective universal serial bus (USB) flash disk type microfluidic chip electrophoresis (MCE) was developed by using poly(dimethylsiloxane) based soft lithography and dry film based printed circuit board etching techniques in this paper. The MCE had a microchannel diameter of 375 μm and an effective length of 25 mm. Equipped with a conventional online electrochemical detector, the device enabled effectively separation of bovine serum albumin, lysozyme, and cytochrome c in 80 s under the ultra low voltage from a computer USB interface. Compared with traditional capillary electrophoresis, the USB flash disk type MCE is not only portable and inexpensive but also fast with high separation efficiency. PMID:27042249

Ultra High Bypass Integrated System Test

NASA Image and Video Library

2015-09-14

NASA’s Environmentally Responsible Aviation Project, in collaboration with the Federal Aviation Administration (FAA) and Pratt & Whitney, completed testing of an Ultra High Bypass Ratio Turbofan Model in the 9’ x 15’ Low Speed Wind Tunnel at NASA Glenn Research Center. The fan model is representative of the next generation of efficient and quiet Ultra High Bypass Ratio Turbofan Engine designs.

Polymer/metal oxide hybrid dielectrics for low voltage field-effect transistors with solution-processed, high-mobility semiconductors

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

Held, Martin; Schießl, Stefan P.; Gannott, Florentina

Transistors for future flexible organic light-emitting diode (OLED) display backplanes should operate at low voltages and be able to sustain high currents over long times without degradation. Hence, high capacitance dielectrics with low surface trap densities are required that are compatible with solution-processable high-mobility semiconductors. Here, we combine poly(methyl methacrylate) (PMMA) and atomic layer deposition hafnium oxide (HfO{sub x}) into a bilayer hybrid dielectric for field-effect transistors with a donor-acceptor polymer (DPPT-TT) or single-walled carbon nanotubes (SWNTs) as the semiconductor and demonstrate substantially improved device performances for both. The ultra-thin PMMA layer ensures a low density of trap states atmore » the semiconductor-dielectric interface while the metal oxide layer provides high capacitance, low gate leakage and superior barrier properties. Transistors with these thin (≤70 nm), high capacitance (100–300 nF/cm{sup 2}) hybrid dielectrics enable low operating voltages (<5 V), balanced charge carrier mobilities and low threshold voltages. Moreover, the hybrid layers substantially improve the bias stress stability of the transistors compared to those with pure PMMA and HfO{sub x} dielectrics.« less

30 CFR 75.826 - High-voltage trailing cables.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-voltage trailing cables. 75.826 Section 75...-Voltage Longwalls § 75.826 High-voltage trailing cables. High-voltage trailing cables must: (a) Meet existing trailing cable requirements and the approval requirements of the high-voltage continuous mining...

Versatile, high-sensitivity faraday cup array for ion implanters

DOEpatents

Musket, Ronald G.; Patterson, Robert G.

2003-01-01

An improved Faraday cup array for determining the dose of ions delivered to a substrate during ion implantation and for monitoring the uniformity of the dose delivered to the substrate. The improved Faraday cup array incorporates a variable size ion beam aperture by changing only an insertable plate that defines the aperture without changing the position of the Faraday cups which are positioned for the operation of the largest ion beam aperture. The design enables the dose sensitivity range, typically 10.sup.11 -10.sup.18 ions/cm.sup.2 to be extended to below 10.sup.6 ions/cm.sup.2. The insertable plate/aperture arrangement is structurally simple and enables scaling to aperture areas between <1 cm.sup.2 and >750 cm.sup.2, and enables ultra-high vacuum (UHV) applications by incorporation of UHV-compatible materials.

Ultra-high resolution and high-brightness AMOLED

NASA Astrophysics Data System (ADS)

Wacyk, Ihor; Ghosh, Amal; Prache, Olivier; Draper, Russ; Fellowes, Dave

2012-06-01

As part of its continuing effort to improve both the resolution and optical performance of AMOLED microdisplays, eMagin has recently developed an SXGA (1280×3×1024) microdisplay under a US Army RDECOM CERDEC NVESD contract that combines the world's smallest OLED pixel pitch with an ultra-high brightness green OLED emitter. This development is aimed at next-generation HMD systems with "see-through" and daylight imaging requirements. The OLED pixel array is built on a 0.18-micron CMOS backplane and contains over 4 million individually addressable pixels with a pixel pitch of 2.7 × 8.1 microns, resulting in an active area of 0.52 inches diagonal. Using both spatial and temporal enhancement, the display can provide over 10-bits of gray-level control for high dynamic range applications. The new pixel design also enables the future implementation of a full-color QSXGA (2560 × RGB × 2048) microdisplay in an active area of only 1.05 inch diagonal. A low-power serialized low-voltage-differential-signaling (LVDS) interface is integrated into the display for use as a remote video link for tethered systems. The new SXGA backplane has been combined with the high-brightness green OLED device developed by eMagin under an NVESD contract. This OLED device has produced an output brightness of more than 8000fL with all pixels on; lifetime measurements are currently underway and will presented at the meeting. This paper will describe the operational features and first optical and electrical test results of the new SXGA demonstrator microdisplay.

High-frequency high-voltage high-power DC-to-DC converters

NASA Astrophysics Data System (ADS)

Wilson, T. G.; Owen, H. A., Jr.; Wilson, P. M.

1981-07-01

The current and voltage waveshapes associated with the power transitor and the power diode in an example current-or-voltage step-up (buck-boost) converter were analyzed to highlight the problems and possible tradeoffs involved in the design of high voltage high power converters operating at switching frequencies in the range of 100 Khz. Although the fast switching speeds of currently available power diodes and transistors permit converter operation at high switching frequencies, the resulting time rates of changes of current coupled with parasitic inductances in series with the semiconductor switches, produce large repetitive voltage transients across the semiconductor switches, potentially far in excess of the device voltage ratings. The need is established for semiconductor switch protection circuitry to control the peak voltages appearing across the semiconductor switches, as well as to provide the waveshaping action require for a given semiconductor device. The possible tradeoffs, as well as the factors affecting the tradeoffs that must be considered in order to maximize the efficiency of the converters are enumerated.

High-frequency high-voltage high-power DC-to-DC converters

NASA Technical Reports Server (NTRS)

Wilson, T. G.; Owen, H. A., Jr.; Wilson, P. M.

1981-01-01

The current and voltage waveshapes associated with the power transitor and the power diode in an example current-or-voltage step-up (buck-boost) converter were analyzed to highlight the problems and possible tradeoffs involved in the design of high voltage high power converters operating at switching frequencies in the range of 100 Khz. Although the fast switching speeds of currently available power diodes and transistors permit converter operation at high switching frequencies, the resulting time rates of changes of current coupled with parasitic inductances in series with the semiconductor switches, produce large repetitive voltage transients across the semiconductor switches, potentially far in excess of the device voltage ratings. The need is established for semiconductor switch protection circuitry to control the peak voltages appearing across the semiconductor switches, as well as to provide the waveshaping action require for a given semiconductor device. The possible tradeoffs, as well as the factors affecting the tradeoffs that must be considered in order to maximize the efficiency of the converters are enumerated.

High-frequency high-voltage high-power DC-to-DC converters

NASA Technical Reports Server (NTRS)

Wilson, T. G.; Owen, H. A.; Wilson, P. M.

1982-01-01

A simple analysis of the current and voltage waveshapes associated with the power transistor and the power diode in an example current-or-voltage step-up (buck-boost) converter is presented. The purpose of the analysis is to provide an overview of the problems and design trade-offs which must be addressed as high-power high-voltage converters are operated at switching frequencies in the range of 100 kHz and beyond. Although the analysis focuses on the current-or-voltage step-up converter as the vehicle for discussion, the basic principles presented are applicable to other converter topologies as well.

High-frequency high-voltage high-power DC-to-DC converters

NASA Astrophysics Data System (ADS)

Wilson, T. G.; Owen, H. A.; Wilson, P. M.

1982-09-01

A simple analysis of the current and voltage waveshapes associated with the power transistor and the power diode in an example current-or-voltage step-up (buck-boost) converter is presented. The purpose of the analysis is to provide an overview of the problems and design trade-offs which must be addressed as high-power high-voltage converters are operated at switching frequencies in the range of 100 kHz and beyond. Although the analysis focuses on the current-or-voltage step-up converter as the vehicle for discussion, the basic principles presented are applicable to other converter topologies as well.

Temperature controlled high voltage regulator

DOEpatents

Chiaro, Jr., Peter J.; Schulze, Gerald K.

2004-04-20

A temperature controlled high voltage regulator for automatically adjusting the high voltage applied to a radiation detector is described. The regulator is a solid state device that is independent of the attached radiation detector, enabling the regulator to be used by various models of radiation detectors, such as gas flow proportional radiation detectors.

Comparison of ultra high performance supercritical fluid chromatography, ultra high performance liquid chromatography, and gas chromatography for the separation of synthetic cathinones.

PubMed

Carnes, Stephanie; O'Brien, Stacey; Szewczak, Angelica; Tremeau-Cayel, Lauriane; Rowe, Walter F; McCord, Bruce; Lurie, Ira S

2017-09-01

A comparison of ultra high performance supercritical fluid chromatography, ultra high performance liquid chromatography, and gas chromatography for the separation of synthetic cathinones has been conducted. Nine different mixtures of bath salts were analyzed in this study. The three different chromatographic techniques were examined using a general set of controlled synthetic cathinones as well as a variety of other synthetic cathinones that exist as positional isomers. Overall 35 different synthetic cathinones were analyzed. A variety of column types and chromatographic modes were examined for developing each separation. For the ultra high performance supercritical fluid chromatography separations, analyses were performed using a series of Torus and Trefoil columns with either ammonium formate or ammonium hydroxide as additives, and methanol, ethanol or isopropanol organic solvents as modifiers. Ultra high performance liquid chromatographic separations were performed in both reversed phase and hydrophilic interaction chromatographic modes using SPP C18 and SPP HILIC columns. Gas chromatography separations were performed using an Elite-5MS capillary column. The orthogonality of ultra high performance supercritical fluid chromatography, ultra high performance liquid chromatography, and gas chromatography was examined using principal component analysis. For the best overall separation of synthetic cathinones, the use of ultra high performance supercritical fluid chromatography in combination with gas chromatography is recommended. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

30 CFR 77.810 - High-voltage equipment; grounding.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-voltage equipment; grounding. 77.810... COAL MINES Surface High-Voltage Distribution § 77.810 High-voltage equipment; grounding. Frames, supporting structures, and enclosures of stationary, portable, or mobile high-voltage equipment shall be...

Development of a compact generator for gigawatt, nanosecond high-voltage pulses.

PubMed

Zhou, Lin; Jiang, Zhanxing; Liang, Chuan; Li, Mingjia; Wang, Wenchuan; Li, Zhenghong

2016-03-01

A compact generator producing 2.2-ns 1.5 GW high-voltage pulses was developed. The generator employed a 27.6 Ω, 0.9 ns pulse-forming-line (PFL), which was charged by an iron core transformer with a turn ratio of 2:33.5 and a coefficient of 0.94. A 1.2 μF, 20 kV capacitor and a hydrogen thyratron were used in the primary circuit. When the thyratron closed at 14.5 kV, 3.4% of the energy stored in the capacitor was delivered to the PFL in 850 ns, producing a peak voltage of up to ∼500 kV. In addition, the principle of triple resonance transformation was employed by adding a 50 pF tuning capacitor and a 1.15 mH inductor between the transformer and the PFL, which led to a significant reduction of the duration and peak value of the transformer voltage without reducing that in the PFL. Meanwhile, an adjustable self-break oil switch was applied. By using transmission lines with impedance overmatched to that of the PFL, the generator delivered a 512 kV pulse across an electron beam diode, generating radiation with a dose of 20 mR/pulse at 20 cm ahead of the diode. The generator provides an excellent ultra-short radiation pulse source for the studies on radiation physics.

Surface interactions and high-voltage current collection

NASA Technical Reports Server (NTRS)

Mandell, M. J.; Katz, I.

1985-01-01

Spacecraft of the future will be larger and have higher power requirements than any flown to date. For several reasons, it is desirable to operate a high power system at high voltage. While the optimal voltages for many future missions are in the range 500 to 5000 volts, the highest voltage yet flown is approximately 100 volts. The NASCAP/LEO code is being developed to embody the phenomenology needed to model the environmental interactions of high voltage spacecraft. Some plasma environment are discussed. The treatment of the surface conductivity associated with emitted electrons and some simulations by NASCAP/LEO of ground based high voltage interaction experiments are described.

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

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

Calibration of high voltages at the ppm level by the difference of ^{83{m}}Kr conversion electron lines at the KATRIN experiment

NASA Astrophysics Data System (ADS)

Arenz, M.; Baek, W.-J.; Beck, M.; Beglarian, A.; Behrens, J.; Bergmann, T.; Berlev, A.; Besserer, U.; Blaum, K.; Bode, T.; Bornschein, B.; Bornschein, L.; Brunst, T.; Buzinsky, N.; Chilingaryan, S.; Choi, W. Q.; Deffert, M.; Doe, P. J.; Dragoun, O.; Drexlin, G.; Dyba, S.; Edzards, F.; Eitel, K.; Ellinger, E.; Engel, R.; Enomoto, S.; Erhard, M.; Eversheim, D.; Fedkevych, M.; Fischer, S.; Formaggio, J. A.; Fränkle, F. M.; Franklin, G. B.; Friedel, F.; Fulst, A.; Gil, W.; Glück, F.; Ureña, A. Gonzalez; Grohmann, S.; Grössle, R.; Gumbsheimer, R.; Hackenjos, M.; Hannen, V.; Harms, F.; Haußmann, N.; Heizmann, F.; Helbing, K.; Herz, W.; Hickford, S.; Hilk, D.; Hillesheimer, D.; Howe, M. A.; Huber, A.; Jansen, A.; Kellerer, J.; Kernert, N.; Kippenbrock, L.; Kleesiek, M.; Klein, M.; Kopmann, A.; Korzeczek, M.; Kovalík, A.; Krasch, B.; Kraus, M.; Kuckert, L.; Lasserre, T.; Lebeda, O.; Letnev, J.; Lokhov, A.; Machatschek, M.; Marsteller, A.; Martin, E. L.; Mertens, S.; Mirz, S.; Monreal, B.; Neumann, H.; Niemes, S.; Off, A.; Osipowicz, A.; Otten, E.; Parno, D. S.; Pollithy, A.; Poon, A. W. P.; Priester, F.; Ranitzsch, P. C.-O.; Rest, O.; Robertson, R. G. H.; Roccati, F.; Rodenbeck, C.; Röllig, M.; Röttele, C.; Ryšavý, M.; Sack, R.; Saenz, A.; Schimpf, L.; Schlösser, K.; Schlösser, M.; Schönung, K.; Schrank, M.; Seitz-Moskaliuk, H.; Sentkerestiová, J.; Sibille, V.; Slezák, M.; Steidl, M.; Steinbrink, N.; Sturm, M.; Suchopar, M.; Suesser, M.; Telle, H. H.; Thorne, L. A.; Thümmler, T.; Titov, N.; Tkachev, I.; Trost, N.; Valerius, K.; Vénos, D.; Vianden, R.; Hernández, A. P. Vizcaya; Weber, M.; Weinheimer, C.; Weiss, C.; Welte, S.; Wendel, J.; Wilkerson, J. F.; Wolf, J.; Wüstling, S.; Zadoroghny, S.

2018-05-01

The neutrino mass experiment KATRIN requires a stability of 3 ppm for the retarding potential at - 18.6 kV of the main spectrometer. To monitor the stability, two custom-made ultra-precise high-voltage dividers were developed and built in cooperation with the German national metrology institute Physikalisch-Technische Bundesanstalt (PTB). Until now, regular absolute calibration of the voltage dividers required bringing the equipment to the specialised metrology laboratory. Here we present a new method based on measuring the energy difference of two ^{83{m}}Kr conversion electron lines with the KATRIN setup, which was demonstrated during KATRIN's commissioning measurements in July 2017. The measured scale factor M=1972.449(10) of the high-voltage divider K35 is in agreement with the last PTB calibration 4 years ago. This result demonstrates the utility of the calibration method, as well as the long-term stability of the voltage divider.

Modular high voltage power supply for chemical analysis

DOEpatents

Stamps, James F [Livermore, CA; Yee, Daniel D [Dublin, CA

2007-01-09

A high voltage power supply for use in a system such as a microfluidics system, uses a DC--DC converter in parallel with a voltage-controlled resistor. A feedback circuit provides a control signal for the DC--DC converter and voltage-controlled resistor so as to regulate the output voltage of the high voltage power supply, as well as, to sink or source current from the high voltage supply.

Modular high voltage power supply for chemical analysis

DOEpatents

Stamps, James F [Livermore, CA; Yee, Daniel D [Dublin, CA

2010-05-04

A high voltage power supply for use in a system such as a microfluidics system, uses a DC-DC converter in parallel with a voltage-controlled resistor. A feedback circuit provides a control signal for the DC-DC converter and voltage-controlled resistor so as to regulate the output voltage of the high voltage power supply, as well as, to sink or source current from the high voltage supply.

Modular high voltage power supply for chemical analysis

DOEpatents

Stamps, James F [Livermore, CA; Yee, Daniel D [Dublin, CA

2008-07-15

A high voltage power supply for use in a system such as a microfluidics system, uses a DC-DC converter in parallel with a voltage-controlled resistor. A feedback circuit provides a control signal for the DC-DC converter and voltage-controlled resistor so as to regulate the output voltage of the high voltage power supply, as well as, to sink or source current from the high voltage supply.

Method for producing an atomic oxygen beam

NASA Technical Reports Server (NTRS)

Outlaw, Ronald A. (Inventor)

1989-01-01

A method for producing an atomic oxygen beam is provided by the present invention. First, a material 10' is provided which dissociates molecular oxygen and dissolves atomic oxygen into its bulk. Next, molecular oxygen is exposed to entrance surface 11' of material 10'. Next, material 10' is heated by heater 17' to facilitate the permeation of atomic oxygen through material 10' to the UHV side 12'. UHV side 12' is interfaced with an ultra-high vacuum (UHV) environment provided by UHV pump 15'. The atomic oxygen on the UHV side 12' is excited to a non-binding state by exciter 14' thus producing the release of atomic oxygen to form an atomic oxygen beam 35'.

Comparative High Voltage Impulse Measurement

PubMed Central

FitzPatrick, Gerald J.; Kelley, Edward F.

1996-01-01

A facility has been developed for the determination of the ratio of pulse high voltage dividers over the range from 10 kV to 300 kV using comparative techniques with Kerr electro-optic voltage measurement systems and reference resistive voltage dividers. Pulse voltage ratios of test dividers can be determined with relative expanded uncertainties of 0.4 % (coverage factor k = 2 and thus a two standard deviation estimate) or less using the complementary resistive divider/Kerr cell reference systems. This paper describes the facility and specialized procedures used at NIST for the determination of test voltage divider ratios through comparative techniques. The error sources and special considerations in the construction and use of reference voltage dividers to minimize errors are discussed, and estimates of the measurement uncertainties are presented. PMID:27805083

An Ultra-Low Voltage Analog Front End for Strain Gauge Sensory System Application in 0.18µm CMOS

NASA Astrophysics Data System (ADS)

Edward, Alexander; Chan, Pak Kwong

This paper presents analysis and design of a new ultra-low voltage analog front end (AFE) dedicated to strain sensor applications. The AFE, designed in 0.18µm CMOS process, features a chopper-stabilized instrumentation amplifier (IA), a balanced active MOSFET-C 2nd order low pass filter (LPF), a clock generator and a voltage booster which operate at supply voltage (Vdd) of 0.6V. The designed IA achieves 30dB of closed-loop gain, 101dB of common-mode rejection ratio (CMRR) at 50Hz, 80dB of power-supply rejection ratio (PSRR) at 50Hz, thermal noise floor of 53.4 nV/√Hz, current consumption of 14µA, and noise efficiency factor (NEF) of 9.7. The high CMRR and rail-to-rail output swing capability is attributed to a new low voltage realization of the active-bootstrapped technique using a pseudo-differential gain-boosting operational transconductance amplifier (OTA) and proposed current-driven bulk (CDB) biasing technique. An output capacitor-less low-dropout regulator (LDO), with a new fast start-up LPF technique, is used to regulate this 0.6V supply from a 0.8-1.0V energy harvesting power source. It achieves power supply rejection (PSR) of 42dB at frequency of 1MHz. A cascode compensated pseudo differential amplifier is used as the filter's building block for low power design. The filter's single-ended-to-balanced converter is implemented using a new low voltage amplifier with two-stage common-mode cancellation. The overall AFE was simulated to have 65.6dB of signal-to-noise ratio (SNR), total harmonic distortion (THD) of less than 0.9% for a 100Hz sinusoidal maximum input signal, bandwidth of 2kHz, and power consumption of 51.2µW. Spectre RF simulations were performed to validate the design using BSIM3V3 transistor models provided by GLOBALFOUNDRIES 0.18µm CMOS process.

30 CFR 75.813 - High-voltage longwalls; scope.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-voltage longwalls; scope. 75.813 Section 75.813 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage Distribution High-Voltage Longwalls § 75.813 High-voltage...

30 CFR 75.813 - High-voltage longwalls; scope.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false High-voltage longwalls; scope. 75.813 Section 75.813 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage Distribution High-Voltage Longwalls § 75.813 High-voltage...

The research of full automatic oil filtering control technology of high voltage insulating oil

NASA Astrophysics Data System (ADS)

Gong, Gangjun; Zhang, Tong; Yan, Guozeng; Zhang, Han; Chen, Zhimin; Su, Chang

2017-09-01

In this paper, the design scheme of automatic oil filter control system for transformer oil in UHV substation is summarized. The scheme specifically includes the typical double tank filter connection control method of the transformer oil of the UHV substation, which distinguishes the single port and the double port connection structure of the oil tank. Finally, the design scheme of the temperature sensor and respirator is given in detail, and the detailed evaluation and application scenarios are given for reference.

High voltage power transistor development

NASA Technical Reports Server (NTRS)

Hower, P. L.

1981-01-01

Design considerations, fabrication procedures, and methods of evaluation for high-voltage power-transistor development are discussed. Technique improvements such as controlling the electric field at the surface and perserving lifetimes in the collector region which have advanced the state of the art in high-voltage transistors are discussed. These improvements can be applied directly to the development of 1200 volt, 200 ampere transistors.

Multijunction high-voltage solar cell

NASA Technical Reports Server (NTRS)

Evans, J. C., Jr.; Goradia, C.; Chai, A. T.

1981-01-01

Multijunction cell allows for fabrication of high-voltage solar cell on single semiconductor wafer. Photovoltaic energy source using cell is combined on wafer with circuit it is to power. Cell consists of many voltage-generating regions internally or externally interconnected to give desired voltage and current combination. For computer applications, module is built on silicon wafer with energy for internal information processing and readouts derived from external light source.

Ultra-low switching energy and scaling in electric-field-controlled nanoscale magnetic tunnel junctions with high resistance-area product

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

Grezes, C.; Alzate, J. G.; Cai, X.

2016-01-04

We report electric-field-induced switching with write energies down to 6 fJ/bit for switching times of 0.5 ns, in nanoscale perpendicular magnetic tunnel junctions (MTJs) with high resistance-area product and diameters down to 50 nm. The ultra-low switching energy is made possible by a thick MgO barrier that ensures negligible spin-transfer torque contributions, along with a reduction of the Ohmic dissipation. We find that the switching voltage and time are insensitive to the junction diameter for high-resistance MTJs, a result accounted for by a macrospin model of purely voltage-induced switching. The measured performance enables integration with same-size CMOS transistors in compact memorymore » and logic integrated circuits.« less

Breakdown in helium in high-voltage open discharge with subnanosecond current front rise

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

Schweigert, I. V., E-mail: ischweig@itam.nsc.ru; Alexandrov, A. L.; Bokhan, P. A.

Investigations of high-voltage open discharge in helium have shown a possibility of generation of current pulses with subnanosecond front rise, due to ultra-fast breakdown development. The open discharge is ignited between two planar cathodes with mesh anode in the middle between them. For gas pressure 6 Torr and 20 kV applied voltage, the rate of current rise reaches 500 A/(cm{sup 2} ns) for current density 200 A/cm{sup 2} and more. The time of breakdown development was measured for different helium pressures and a kinetic model of breakdown in open discharge is presented, based on elementary reactions for electrons, ions andmore » fast atoms. The model also includes various cathode emission processes due to cathode bombardment by ions, fast atoms, electrons and photons of resonant radiation with Doppler shift of frequency. It is shown, that the dominating emission processes depend on the evolution of the discharge voltage during the breakdown. In the simulations, two cases of voltage behavior were considered: (i) the voltage is kept constant during the breakdown; (ii) the voltage is reduced with the growth of current. For the first case, the exponentially growing current is maintained due to photoemission by the resonant photons with Doppler-shifted frequency. For the second case, the dominating factor of current growth is the secondary electron emission. In both cases, the subnanosecond rise of discharge current was obtained. Also the effect of gas pressure on breakdown development was considered. It was found that for 20 Torr gas pressure the time of current rise decreases to 0.1 ns, which is in agreement with experimental data.« less

Development of an environmental high-voltage electron microscope for reaction science.

PubMed

Tanaka, Nobuo; Usukura, Jiro; Kusunoki, Michiko; Saito, Yahachi; Sasaki, Katuhiro; Tanji, Takayoshi; Muto, Shunsuke; Arai, Shigeo

2013-02-01

Environmental transmission electron microscopy and ultra-high resolution electron microscopic observation using aberration correctors have recently emerged as topics of great interest. The former method is an extension of the so-called in situ electron microscopy that has been performed since the 1970s. Current research in this area has been focusing on dynamic observation with atomic resolution under gaseous atmospheres and in liquids. Since 2007, Nagoya University has been developing a new 1-MV high voltage (scanning) transmission electron microscope that can be used to observe nanomaterials under conditions that include the presence of gases, liquids and illuminating lights, and it can be also used to perform mechanical operations to nanometre-sized areas as well as electron tomography and elemental analysis by electron energy loss spectroscopy. The new instrument has been used to image and analyse various types of samples including biological ones.

Ultra high vacuum heating and rotating specimen stage

DOEpatents

Coombs, III, Arthur W.

1995-01-01

A heating and rotating specimen stage provides for simultaneous specimen heating and rotating. The stage is ideally suited for operation in ultrahigh vacuum (1.times.10.sup.-9 torr or less), but is useful at atmosphere and in pressurized systems as well. A specimen is placed on a specimen holder that is attached to a heater that, in turn, is attached to a top housing. The top housing is rotated relative to a bottom housing and electrically connected thereto by electrically conductive brushes. This stage is made of materials that are compatible with UHV, able to withstand high temperatures, possess low outgassing rates, are gall and seize resistant, and are able to carry substantial electrical loading without overheating.

Optimization and testing of solid thin film lubrication deposition processes

NASA Astrophysics Data System (ADS)

Danyluk, Michael J.

A novel method for testing solid thin films in rolling contact fatigue (RCF) under ultra-high vacuum (UHV) and high rotational speeds (130 Hz) is presented in this thesis. The UHV-RCF platform is used to quantify the adhesion and lubrication aspects of two thin film coatings deposited on ball-bearings using a physical vapor deposition ion plating process. Plasma properties during ion plating were measured using a Langmuir probe and there is a connection between ion flux, film stress, film adhesion, process voltage, pressure, and RCF life. The UHV-RCF platform and vacuum chamber were constructed using off-the-shelf components and 88 RCF tests in high vacuum have been completed. Maximum RCF life was achieved by maintaining an ion flux between 10 13 to 1015 (cm-2 s-1) with a process voltage and pressure near 1.5 kV and 15 mTorr. Two controller schemes were investigated to maintain optimal plasma conditions for maximum RCF life: PID and LQR. Pressure disturbances to the plasma have a detrimental effect on RCF life. Control algorithms that mitigate pressure and voltage disturbances already exist. However, feedback from the plasma to detect disturbances has not been explored related to deposition processes in the thin-film science literature. Manometer based pressure monitoring systems have a 1 to 2 second delay time and are too slow to detect common pressure bursts during the deposition process. Plasma diagnostic feedback is much faster, of the order of 0.1 second. Plasma total-current feedback was used successfully to detect a typical pressure disturbance associated with the ion plating process. Plasma current is related to ion density and process pressure. A real-time control application was used to detect the pressure disturbance by monitoring plasma-total current and converting it to feedback-input to a pressure control system. Pressure overshoot was eliminated using a nominal PID controller with feedback from a plasma-current diagnostic measurement tool.

High-quality EuO thin films the easy way via topotactic transformation

DOE PAGES

Mairoser, Thomas; Mundy, Julia A.; Melville, Alexander; ...

2015-07-16

Epitaxy is widely employed to create highly oriented crystalline films. A less appreciated, but nonetheless powerful means of creating such films is via topotactic transformation, in which a chemical reaction transforms a single crystal of one phase into a single crystal of a different phase, which inherits its orientation from the original crystal. Topotactic reactions may be applied to epitactic films to substitute, add or remove ions to yield epitactic films of different phases. Here we exploit a topotactic reduction reaction to provide a non-ultra-high vacuum (UHV) means of growing highly oriented single crystalline thin films of the easily over-oxidizedmore » half-metallic semiconductor europium monoxide (EuO) with a perfection rivalling that of the best films of the same material grown by molecular-beam epitaxy or UHV pulsed-laser deposition. Lastly, as the technique only requires high-vacuum deposition equipment, it has the potential to drastically improve the accessibility of high-quality single crystalline films of EuO as well as other difficult-to-synthesize compounds.« less

OB's high voltage laboratory

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

Not Available

1966-01-01

The January issue of Hi-Tension News provides a detailed description of the advanced surge test facilities and procedures in daily operation at the OB High Voltage Laboratory in Barberton, Ohio. Technical competences achieved in this laboratory contribute to the essential factors of design confirmation to basic studies of ehv insulation systems, conductor and hardware performance, and optimum tower construction. Known throughout the industry for authenticity of its full scale, all weather outdoor testing, OB's High Voltage Laboratory is a full-fledged participant in the NEMA-sponsored program to make testing facilities available on a cooperative basis.

High voltage electrical injuries.

PubMed

Kaloudová, Y; Sín, R; Rihová, H; Brychta, R; Suchánek, I; Martincová, A

2006-01-01

Between 1999 and 2005, a total of 41 patients were hospitalized at the Burn Centre of Brno University Hospital with high voltage electrical injuries, representing 6.06% of the total number of patients treated at the Burn Intensive Care Unit (ICU) for extensive burn trauma. The average age of patients with serious electrotraumas was 27.29 years. The youngest patient was 9 years old, the oldest 64 years. Lethality amounted to 17.07% of the total number of patients. The article clearly shows the sinister dimension (a frighteningly high number of cases) of high voltage electrical injuries suffered outside work context in the vicinity of railway tracks and affecting in particular the youngest age groups--children.

Development of a compact generator for gigawatt, nanosecond high-voltage pulses

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

Zhou, Lin, E-mail: zhoulin-2003@163.com; Jiang, Zhanxing; Liang, Chuan

2016-03-15

A compact generator producing 2.2-ns 1.5 GW high-voltage pulses was developed. The generator employed a 27.6 Ω, 0.9 ns pulse-forming-line (PFL), which was charged by an iron core transformer with a turn ratio of 2:33.5 and a coefficient of 0.94. A 1.2 μF, 20 kV capacitor and a hydrogen thyratron were used in the primary circuit. When the thyratron closed at 14.5 kV, 3.4% of the energy stored in the capacitor was delivered to the PFL in 850 ns, producing a peak voltage of up to ∼500 kV. In addition, the principle of triple resonance transformation was employed by addingmore » a 50 pF tuning capacitor and a 1.15 mH inductor between the transformer and the PFL, which led to a significant reduction of the duration and peak value of the transformer voltage without reducing that in the PFL. Meanwhile, an adjustable self-break oil switch was applied. By using transmission lines with impedance overmatched to that of the PFL, the generator delivered a 512 kV pulse across an electron beam diode, generating radiation with a dose of 20 mR/pulse at 20 cm ahead of the diode. The generator provides an excellent ultra-short radiation pulse source for the studies on radiation physics.« less

30 CFR 77.800 - High-voltage circuits; circuit breakers.

Code of Federal Regulations, 2010 CFR

2010-07-01

... devices to provide protection against under voltage, grounded phase, short circuit and overcurrent. High... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-voltage circuits; circuit breakers. 77.800... COAL MINES Surface High-Voltage Distribution § 77.800 High-voltage circuits; circuit breakers. High...

Electrical safety for high voltage arrays

NASA Technical Reports Server (NTRS)

Marshall, N. A.

1983-01-01

A number of key electrical safety requirements for the high voltage arrays of central station photovoltaic power systems are explored. The suitability of representative industrial DC power switchgear for control and fault protection was evaluated. Included were AC/DC circuit breakers, electromechanical contactors and relays, load interruptors, cold disconnect devices, sectionalizing switches, and high voltage DC fuses. As appropriate, steady state and transient characteristics were analyzed. Failure modes impacting upon operation and maintenance safety were also identified, as were the voltage withstand and current interruption levels.

E-beam high voltage switching power supply

DOEpatents

Shimer, D.W.; Lange, A.C.

1996-10-15

A high-power power supply produces a controllable, constant high voltage output under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules. 5 figs.

E-beam high voltage switching power supply

DOEpatents

Shimer, Daniel W.; Lange, Arnold C.

1996-01-01

A high-power power supply produces a controllable, constant high voltage put under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules.

30 CFR 75.833 - Handling high-voltage trailing cables.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Handling high-voltage trailing cables. 75.833... High-Voltage Longwalls § 75.833 Handling high-voltage trailing cables. (a) Cable handling. (1) Miners must not handle energized trailing cables unless they are wearing high-voltage insulating gloves, which...

Microstructure Investigation of 13Cr-2Mo ODS Steel Components Obtained by High Voltage Electric Discharge Compaction Technique.

PubMed

Bogachev, Igor; Yudin, Artem; Grigoryev, Evgeniy; Chernov, Ivan; Staltsov, Maxim; Khasanov, Oleg; Olevsky, Eugene

2015-11-02

Refractory oxide dispersion strengthened 13Cr-2Mo steel powder was successfully consolidated to near theoretical density using high voltage electric discharge compaction. Cylindrical samples with relative density from 90% to 97% and dimensions of 10 mm in diameter and 10-15 mm in height were obtained. Consolidation conditions such as pressure and voltage were varied in some ranges to determine the optimal compaction regime. Three different concentrations of yttria were used to identify its effect on the properties of the samples. It is shown that the utilized ultra-rapid consolidation process in combination with high transmitted energy allows obtaining high density compacts, retaining the initial structure with minimal grain growth. The experimental results indicate some heterogeneity of the structure which may occur in the external layers of the tested samples due to various thermal and electromagnetic in-processing effects. The choice of the optimal parameters of the consolidation enables obtaining samples of acceptable quality.

Microstructure investigation of 13Cr-2Mo ODS steel components obtained by high voltage electric discharge compaction technique

DOE PAGES

Bogachev, Igor; Yudin, Artem; Grigoryev, Evgeniy; ...

2015-11-02

Refractory oxide dispersion strengthened 13Cr-2Mo steel powder was successfully consolidated to near theoretical density using high voltage electric discharge compaction. Cylindrical samples with relative density from 90% to 97% and dimensions of 10 mm in diameter and 10–15 mm in height were obtained. Consolidation conditions such as pressure and voltage were varied in some ranges to determine the optimal compaction regime. Three different concentrations of yttria were used to identify its effect on the properties of the samples. It is shown that the utilized ultra-rapid consolidation process in combination with high transmitted energy allows obtaining high density compacts, retaining themore » initial structure with minimal grain growth. The experimental results indicate some heterogeneity of the structure which may occur in the external layers of the tested samples due to various thermal and electromagnetic in-processing effects. As a result, the choice of the optimal parameters of the consolidation enables obtaining samples of acceptable quality.« less

Ultra high vacuum heating and rotating specimen stage

DOEpatents

Coombs, A.W. III

1995-05-02

A heating and rotating specimen stage provides for simultaneous specimen heating and rotating. The stage is ideally suited for operation in ultrahigh vacuum (1{times}10{sup {minus}9} torr or less), but is useful at atmosphere and in pressurized systems as well. A specimen is placed on a specimen holder that is attached to a heater that, in turn, is attached to a top housing. The top housing is rotated relative to a bottom housing and electrically connected thereto by electrically conductive brushes. This stage is made of materials that are compatible with UHV, able to withstand high temperatures, possess low outgassing rates, are gall and seize resistant, and are able to carry substantial electrical loading without overheating. 5 figs.

New developments in the field of high voltage and extra-high voltage cables

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

Jocteur, R.

1990-04-01

In this paper, the author presents the developments in progress at the present time in France concerning the high voltage (HV) and extra-high voltage (EHV) cables with synthetic insulation and their accessories up to the 500 kV range. The authors have adopted a maximum operating field strength approaching 16 kV/mm (405 V/mil) for low density polyethylene (LDPE) insulated cables. The on-going studies should allow to bring the maximum operating field strength for crosslinked polyethylene (XLPE) insulation from 7 to 10 kV/mm (180 to 255 V/mil) and cables could be manufactured more economically with this material.

Quantile Regression for Analyzing Heterogeneity in Ultra-high Dimension

PubMed Central

Wang, Lan; Wu, Yichao

2012-01-01

Ultra-high dimensional data often display heterogeneity due to either heteroscedastic variance or other forms of non-location-scale covariate effects. To accommodate heterogeneity, we advocate a more general interpretation of sparsity which assumes that only a small number of covariates influence the conditional distribution of the response variable given all candidate covariates; however, the sets of relevant covariates may differ when we consider different segments of the conditional distribution. In this framework, we investigate the methodology and theory of nonconvex penalized quantile regression in ultra-high dimension. The proposed approach has two distinctive features: (1) it enables us to explore the entire conditional distribution of the response variable given the ultra-high dimensional covariates and provides a more realistic picture of the sparsity pattern; (2) it requires substantially weaker conditions compared with alternative methods in the literature; thus, it greatly alleviates the difficulty of model checking in the ultra-high dimension. In theoretic development, it is challenging to deal with both the nonsmooth loss function and the nonconvex penalty function in ultra-high dimensional parameter space. We introduce a novel sufficient optimality condition which relies on a convex differencing representation of the penalized loss function and the subdifferential calculus. Exploring this optimality condition enables us to establish the oracle property for sparse quantile regression in the ultra-high dimension under relaxed conditions. The proposed method greatly enhances existing tools for ultra-high dimensional data analysis. Monte Carlo simulations demonstrate the usefulness of the proposed procedure. The real data example we analyzed demonstrates that the new approach reveals substantially more information compared with alternative methods. PMID:23082036

Compact high voltage solid state switch

DOEpatents

Glidden, Steven C.

2003-09-23

A compact, solid state, high voltage switch capable of high conduction current with a high rate of current risetime (high di/dt) that can be used to replace thyratrons in existing and new applications. The switch has multiple thyristors packaged in a single enclosure. Each thyristor has its own gate drive circuit that circuit obtains its energy from the energy that is being switched in the main circuit. The gate drives are triggered with a low voltage, low current pulse isolated by a small inexpensive transformer. The gate circuits can also be triggered with an optical signal, eliminating the trigger transformer altogether. This approach makes it easier to connect many thyristors in series to obtain the hold off voltages of greater than 80 kV.

30 CFR 75.804 - Underground high-voltage cables.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Underground high-voltage cables. 75.804 Section... § 75.804 Underground high-voltage cables. (a) Underground high-voltage cables used in resistance grounded systems shall be equipped with metallic shields around each power conductor with one or more...

30 CFR 75.804 - Underground high-voltage cables.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Underground high-voltage cables. 75.804 Section... § 75.804 Underground high-voltage cables. (a) Underground high-voltage cables used in resistance grounded systems shall be equipped with metallic shields around each power conductor with one or more...

30 CFR 75.804 - Underground high-voltage cables.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Underground high-voltage cables. 75.804 Section... § 75.804 Underground high-voltage cables. (a) Underground high-voltage cables used in resistance grounded systems shall be equipped with metallic shields around each power conductor with one or more...

30 CFR 75.800 - High-voltage circuits; circuit breakers.

Code of Federal Regulations, 2010 CFR

2010-07-01

... shall be equipped with devices to provide protection against under-voltage grounded phase, short circuit... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-voltage circuits; circuit breakers. 75.800... § 75.800 High-voltage circuits; circuit breakers. [Statutory Provisions] High-voltage circuits entering...

HIGH VOLTAGE ION SOURCE

DOEpatents

Luce, J.S.

1960-04-19

A device is described for providing a source of molecular ions having a large output current and with an accelerated energy of the order of 600 kv. Ions are produced in an ion source which is provided with a water-cooled source grid of metal to effect maximum recombination of atomic ions to molecular ions. A very high accelerating voltage is applied to withdraw and accelerate the molecular ions from the source, and means are provided for dumping the excess electrons at the lowest possible potentials. An accelerating grid is placed adjacent to the source grid and a slotted, grounded accelerating electrode is placed adjacent to the accelerating grid. A potential of about 35 kv is maintained between the source grid and accelerating grid, and a potential of about 600 kv is maintained between the accelerating grid and accelerating electrode. In order to keep at a minimum the large number of oscillating electrons which are created when such high voltages are employed in the vicinity of a strong magnetic field, a plurality of high voltage cascaded shields are employed with a conventional electron dumping system being employed between each shield so as to dump the electrons at the lowest possible potential rather than at 600 kv.

High Voltage Seismic Generator

NASA Astrophysics Data System (ADS)

Bogacz, Adrian; Pala, Damian; Knafel, Marcin

2015-04-01

This contribution describes the preliminary result of annual cooperation of three student research groups from AGH UST in Krakow, Poland. The aim of this cooperation was to develop and construct a high voltage seismic wave generator. Constructed device uses a high-energy electrical discharge to generate seismic wave in ground. This type of device can be applied in several different methods of seismic measurement, but because of its limited power it is mainly dedicated for engineering geophysics. The source operates on a basic physical principles. The energy is stored in capacitor bank, which is charged by two stage low to high voltage converter. Stored energy is then released in very short time through high voltage thyristor in spark gap. The whole appliance is powered from li-ion battery and controlled by ATmega microcontroller. It is possible to construct larger and more powerful device. In this contribution the structure of device with technical specifications is resented. As a part of the investigation the prototype was built and series of experiments conducted. System parameter was measured, on this basis specification of elements for the final device were chosen. First stage of the project was successful. It was possible to efficiently generate seismic waves with constructed device. Then the field test was conducted. Spark gap wasplaced in shallowborehole(0.5 m) filled with salt water. Geophones were placed on the ground in straight line. The comparison of signal registered with hammer source and sparker source was made. The results of the test measurements are presented and discussed. Analysis of the collected data shows that characteristic of generated seismic signal is very promising, thus confirms possibility of practical application of the new high voltage generator. The biggest advantage of presented device after signal characteristics is its size which is 0.5 x 0.25 x 0.2 m and weight approximately 7 kg. This features with small li-ion battery makes

Phosphorus Enrichment as a New Composition in the Solid Electrolyte Interphase of High-Voltage Cathodes and Its Effects on Battery Cycling

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

Yan, Pengfei; Zheng, Jianming; Kuppan, Saravanan

2015-11-10

Immersion of a solid into liquid often leads to the modification of both the structure and chemistry of surface of the solid, which subsequently affects the chemical and physical properties of the system. For the case of the rechargeable lithium ion battery, such a surface modification is termed as solid electrolyte interphase (SEI) layer, which has been perceived to play critical role for the stable operation of the batteries. However, the structure and chemical composition of SEI layer and its spatial distribution and dependence on the battery operating condition remain unclear. By using aberration corrected scanning transmission electron microscopy coupledmore » with ultra-high sensitive energy dispersive x-ray spectroscopy, we probed the structure and chemistry of SEI layer on several high voltage cathodes. We show that layer-structured cathodes, when cycled at a high cut off voltage, can form a P-rich SEI layer on their surface, which is a direct evidence of Li-salt (LiPF6) decomposition. Our systematical investigations indicate such cathode/Li-salt side reaction shows strong dependence on structure of the cathode materials, operating voltage and temperature, indicating the feasibility of SEI engineering. These findings provide us valuable insights into the complex interface between the high-voltage cathode and the electrolyte.« less

Programmable high-output-impedance, large-voltage compliance, microstimulator for low-voltage biomedical applications.

PubMed

Farahmand, Sina; Maghami, Mohammad Hossein; Sodagar, Amir M

2012-01-01

This paper reports on the design of a programmable, high output impedance, large voltage compliance microstimulator for low-voltage biomedical applications. A 6-bit binary-weighted digital to analog converter (DAC) is used to generate biphasic stimulus current pulses. A compact current mirror with large output voltage compliance and high output resistance conveys the current pulses to the target tissue. Designed and simulated in a standard 0.18µm CMOS process, the microstimulator circuit is capable of delivering a maximum stimulation current of 160µA to a 10-kΩ resistive load. Operated at a 1.8-V supply voltage, the output stage exhibits a voltage compliance of 1.69V and output resistance of 160MΩ at full scale stimulus current. Layout of the core microelectrode circuit measures 25.5µm×31.5µm.

Physicochemical assessment criteria for high-voltage pulse capacitors

NASA Astrophysics Data System (ADS)

Darian, L. A.; Lam, L. Kh.

2016-12-01

In the paper, the applicability of decomposition products of internal insulation of high-voltage pulse capacitors is considered (aging is the reason for decomposition products of internal insulation). Decomposition products of internal insulation of high-voltage pulse capacitors can be used to evaluate their quality when in operation and in service. There have been three generations of markers of aging of insulation as in the case with power transformers. The area of applicability of markers of aging of insulation for power transformers has been studied and the area can be extended to high-voltage pulse capacitors. The research reveals that there is a correlation between the components and quantities of markers of aging of the first generation (gaseous decomposition products of insulation) dissolved in insulating liquid and the remaining life of high-voltage pulse capacitors. The application of markers of aging to evaluate the remaining service life of high-voltage pulse capacitor is a promising direction of research, because the design of high-voltage pulse capacitors keeps stability of markers of aging of insulation in high-voltage pulse capacitors. It is necessary to continue gathering statistical data concerning development of markers of aging of the first generation. One should also carry out research aimed at estimation of the remaining life of capacitors using markers of the second and the third generation.

Physicochemical assessment criteria for high-voltage pulse capacitors

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

Darian, L. A., E-mail: LDarian@rambler.ru; Lam, L. Kh.

In the paper, the applicability of decomposition products of internal insulation of high-voltage pulse capacitors is considered (aging is the reason for decomposition products of internal insulation). Decomposition products of internal insulation of high-voltage pulse capacitors can be used to evaluate their quality when in operation and in service. There have been three generations of markers of aging of insulation as in the case with power transformers. The area of applicability of markers of aging of insulation for power transformers has been studied and the area can be extended to high-voltage pulse capacitors. The research reveals that there is amore » correlation between the components and quantities of markers of aging of the first generation (gaseous decomposition products of insulation) dissolved in insulating liquid and the remaining life of high-voltage pulse capacitors. The application of markers of aging to evaluate the remaining service life of high-voltage pulse capacitor is a promising direction of research, because the design of high-voltage pulse capacitors keeps stability of markers of aging of insulation in high-voltage pulse capacitors. It is necessary to continue gathering statistical data concerning development of markers of aging of the first generation. One should also carry out research aimed at estimation of the remaining life of capacitors using markers of the second and the third generation.« less

Multijunction high voltage concentrator solar cells

NASA Technical Reports Server (NTRS)

Valco, G. J.; Kapoor, V. J.; Evans, J. C.; Chai, A.-T.

1981-01-01

The standard integrated circuit technology has been developed to design and fabricate new innovative planar multi-junction solar cell chips for concentrated sunlight applications. This 1 cm x 1 cm cell consisted of several voltage generating regions called unit cells which were internally connected in series within a single chip resulting in high open circuit voltages. Typical open-circuit voltages of 3.6 V and short-circuit currents of 90 ma were obtained at 80 AM1 suns. A dramatic increase in both short circuit current and open circuit voltage with increased light levels was observed.

Detecting Faults In High-Voltage Transformers

NASA Technical Reports Server (NTRS)

Blow, Raymond K.

1988-01-01

Simple fixture quickly shows whether high-voltage transformer has excessive voids in dielectric materials and whether high-voltage lead wires too close to transformer case. Fixture is "go/no-go" indicator; corona appears if transformer contains such faults. Nests in wire mesh supported by cap of clear epoxy. If transformer has defects, blue glow of corona appears in mesh and is seen through cap.

In situ sputter cleaning of thin film metal substrates for UHV-TEM corrosion studies.

NASA Technical Reports Server (NTRS)

Heinemann, K.; Poppa, H.

1973-01-01

A prerequisite for conducting valid corrosion experiments by in situ electron microscopy techniques is not only the achievement of UHV background pressure conditions at the site of the specimen but also the ability to clean the surface of the thin metal substrate specimen before initiation of the corrosive interaction. A miniaturized simple ion gun has been constructed for this purpose. The gun is small enough to be incorporated into an UHV electron microscope specimen chamber with hot stage in such a way as to permit bombardment of the substrate specimen while observing it by transmission electron microscopy TEM. It is shown that the ion beam generated is confined well enough to cause a sputtering removal of substrate material at a rate of approximately 5-10 A/min and to prevent the sputter deposition of contaminating material from the specimen holder.

Design and development of high efficiency 140W space TWT with graphite collector

NASA Astrophysics Data System (ADS)

Srivastava, V.; Purohit, G.; Sharma, R. K.; Sharma, S. M.; Bera, A.; Bhaskar, P. V.; Singh, R. R.; Prasad, K.; Kiran, V.

2008-05-01

4-stage graphite collector assembly has been designed and developed for a 140W Ku-band space TWT to achieve the collector efficiency more than 80%. The UHV compatible, high density, copper impregnated POCO graphite (DFP-1C) was used to fabricate the four collector electrodes of the 4-stage depressed collector. Copper impregnated graphite material is used for the collector electrodes because of its low secondary electron emission coefficient, high thermal and electrical conductivities, easy machining and brazing, low thermal expansion coefficient and low weight. The graphite material was characterized for the UHV compatibility. The collector electrodes were precisely fabricated by careful machining, and technology was developed for brazing of graphite electrodes with high voltage alumina insulators. Complete TWT with four-stage graphite collector was developed and 140W output power at gain more than 55 dB was achieved. The TWT was pumped from both the gun and the collector ends.

Imaging interactions of metal oxide nanoparticles with macrophage cells by ultra-high resolution scanning electron microscopy techniques.

PubMed

Plascencia-Villa, Germán; Starr, Clarise R; Armstrong, Linda S; Ponce, Arturo; José-Yacamán, Miguel

2012-11-01

Use of engineered metal oxide nanoparticles in a plethora of biological applications and custom products has warned about some possible dose-dependent cytotoxic effects. Macrophages are key components of the innate immune system used to study possible toxic effects and internalization of different nanoparticulate materials. In this work, ultra-high resolution field emission scanning electron microscopy (FE-SEM) was used to offer new insights into the dynamical processes of interaction of nanomaterials with macrophage cells dosed with different concentrations of metal oxide nanoparticles (CeO(2), TiO(2) and ZnO). The versatility of FE-SEM has allowed obtaining a detailed characterization of processes of adsorption and endocytosis of nanoparticles, by using advanced analytical and imaging techniques on complete unstained uncoated cells, including secondary electron imaging, high-sensitive backscattered electron imaging, X-ray microanalysis and stereoimaging. Low voltage BF/DF-STEM confirmed nanoparticle adsorption and internalization into endosomes of CeO(2) and TiO(2), whereas ZnO develop apoptosis after 24 h of interaction caused by dissolution and invasion of cell nucleus. Ultra-high resolution scanning electron microscopy techniques provided new insights into interactions of inorganic nanoparticles with macrophage cells with high spatial resolution.

Imaging interactions of metal oxide nanoparticles with macrophage cells by ultra-high resolution scanning electron microscopy techniques†

PubMed Central

Plascencia-Villa, Germán; Starr, Clarise R.; Armstrong, Linda S.; Ponce, Arturo

2016-01-01

Use of engineered metal oxide nanoparticles in a plethora of biological applications and custom products has warned about some possible dose-dependent cytotoxic effects. Macrophages are key components of the innate immune system used to study possible toxic effects and internalization of different nanoparticulate materials. In this work, ultra-high resolution field emission scanning electron microscopy (FE-SEM) was used to offer new insights into the dynamical processes of interaction of nanomaterials with macrophage cells dosed with different concentrations of metal oxide nanoparticles (CeO2, TiO2 and ZnO). The versatility of FE-SEM has allowed obtaining a detailed characterization of processes of adsorption and endocytosis of nanoparticles, by using advanced analytical and imaging techniques on complete unstained uncoated cells, including secondary electron imaging, high-sensitive backscattered electron imaging, X-ray microanalysis and stereoimaging. Low voltage BF/DF-STEM confirmed nanoparticle adsorption and internalization into endosomes of CeO2 and TiO2, whereas ZnO develop apoptosis after 24 h of interaction caused by dissolution and invasion of cell nucleus. Ultra-high resolution scanning electron microscopy techniques provided new insights into interactions of inorganic nanoparticles with macrophage cells with high spatial resolution. PMID:23023106

Spacecraft high-voltage power supply construction

NASA Technical Reports Server (NTRS)

Sutton, J. F.; Stern, J. E.

1975-01-01

The design techniques, circuit components, fabrication techniques, and past experience used in successful high-voltage power supplies for spacecraft flight systems are described. A discussion of the basic physics of electrical discharges in gases is included and a design rationale for the prevention of electrical discharges is provided. Also included are typical examples of proven spacecraft high-voltage power supplies with typical specifications for design, fabrication, and testing.

Electro-optic high voltage sensor

DOEpatents

Davidson, James R.; Seifert, Gary D.

2003-09-16

A small sized electro-optic voltage sensor capable of accurate measurement of high voltages without contact with a conductor or voltage source is provided. When placed in the presence of an electric field, the sensor receives an input beam of electromagnetic radiation. A polarization beam displacer separates the input beam into two beams with orthogonal linear polarizations and causes one linearly polarized beam to impinge a crystal at a desired angle independent of temperature. The Pockels effect elliptically polarizes the beam as it travels through the crystal. A reflector redirects the beam back through the crystal and the beam displacer. On the return path, the polarization beam displacer separates the elliptically polarized beam into two output beams of orthogonal linear polarization. The system may include a detector for converting the output beams into electrical signals and a signal processor for determining the voltage based on an analysis of the output beams.

High voltage dc--dc converter with dynamic voltage regulation and decoupling during load-generated arcs

DOEpatents

Shimer, D.W.; Lange, A.C.

1995-05-23

A high-power power supply produces a controllable, constant high voltage output under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules. 5 Figs.

High voltage dc-dc converter with dynamic voltage regulation and decoupling during load-generated arcs

DOEpatents

Shimer, Daniel W.; Lange, Arnold C.

1995-01-01

A high-power power supply produces a controllable, constant high voltage output under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules.

High voltage pulse generator. [Patent application

DOEpatents

Fasching, G.E.

1975-06-12

An improved high-voltage pulse generator is described which is especially useful in ultrasonic testing of rock core samples. An N number of capacitors are charged in parallel to V volts and at the proper instance are coupled in series to produce a high-voltage pulse of N times V volts. Rapid switching of the capacitors from the paralleled charging configuration to the series discharging configuration is accomplished by using silicon-controlled rectifiers which are chain self-triggered following the initial triggering of the first rectifier connected between the first and second capacitors. A timing and triggering circuit is provided to properly synchronize triggering pulses to the first SCR at a time when the charging voltage is not being applied to the parallel-connected charging capacitors. The output voltage can be readily increased by adding additional charging networks. The circuit allows the peak level of the output to be easily varied over a wide range by using a variable autotransformer in the charging circuit.

High-conductance low-voltage organic thin film transistor with locally rearranged poly(3-hexylthiophene) domain by current annealing on plastic substrate

NASA Astrophysics Data System (ADS)

Pei, Zingway; Tsai, Hsing-Wang; Lai, Hsin-Cheng

2016-02-01

The organic material based thin film transistors (TFTs) are attractive for flexible optoelectronics applications due to the ability of lager area fabrication by solution and low temperature process on plastic substrate. Recently, the research of organic TFT focus on low operation voltage and high output current to achieve a low power organic logic circuit for optoelectronic device,such as e-paper or OLED displayer. To obtain low voltage and high output current, high gate capacitance and high channel mobility are key factors. The well-arranged polymer chain by a high temperature postannealing, leading enhancement conductivity of polymer film was a general method. However, the thermal annealing applying heat for all device on the substrate and may not applicable to plastic substrate. Therefore, in this work, the low operation voltage and high output current of polymer TFTs was demonstrated by locally electrical bias annealing. The poly(styrene-comethyl methacrylate) (PS-r-PMMA) with ultra-thin thickness is used as gate dielectric that the thickness is controlled by thermal treatment after spin coated on organic electrode. In electrical bias-annealing process, the PS-r- PMMA is acted a heating layer. After electrical bias-annealing, the polymer TFTs obtain high channel mobility at low voltage that lead high output current by a locally annealing of P3HT film. In the future, the locally electrical biasannealing method could be applied on plastic substrate for flexible optoelectronic application.

Liquid Nitrogen as Fast High Voltage Switching Medium

NASA Astrophysics Data System (ADS)

Dickens, J.; Neuber, A.; Haustein, M.; Krile, J.; Krompholz, H.

2002-12-01

Compact pulsed power systems require new switching technologies. For high voltages, liquid nitrogen seems to be a suitable switching medium, with high hold-off voltage, low dielectric constant, and no need for pressurized systems as in high pressure gas switches. The discharge behavior in liquid nitrogen, such as breakdown voltages, formative times, current rise as function of voltage, recovery, etc. are virtually unknown, however. The phenomenology of breakdown in liquid nitrogen is investigated with high speed (temporal resolution < 1 ns) electrical and optical diagnostics, in a coaxial system with 50-Ohm impedance. Discharge current and voltage are determined with transmission line type current sensors and capacitive voltage dividers. The discharge luminosity is measured with photomultiplier tubes. Preliminary results of self-breakdown investigations (gap 1 mm, breakdown voltage 44 kV, non-boiling supercooled nitrogen) show a fast (2 ns) transition from an unknown current level to several mA, a long-duration (100 ns) phase with constant current superimposed by ns-spikes, and a final fast transition to the impedance limited current during several nanoseconds. The optical measurements will be expanded toward spectroscopy and high speed photography with the aim of clarifying the overall breakdown mechanisms, including electronic initiation, bubble formation, bubble dynamics, and their role in breakdown, for different electrode geometries (different macroscopic field enhancements).

High-Voltage Characterization for the Prototype Induction Cells

NASA Astrophysics Data System (ADS)

Huacen, Wang; Kaizhi, Zhang; Long, Wen; Qinggui, Lai; Linwen, Zhang; Jianjun, Deng

2002-12-01

Two linear induction prototype cells expected to work at 250kV, 3kA,with accelerating voltage flattop (±1%) ⩾ 70ns, have been tested to determine their high-voltage characteristics. Each cell is composed of a ferrite core immersed in oil, a gap with curved stainless steel electrodes, a solenoid magnet, and a insulator. The experiments were carried out with full-scale cells. The high voltage pulses were applied to two cells using a 100ns, 12Ω pulse Blumlein. The tests were performed at various high-voltage levels ranging from -250kV to -350kV. No breakdown was observed during the test at vacuum level (7-10) ṡ10-4 Pa. The cell schematic, the experimental set up, and the measured voltage waveforms are presented in this paper.

Full membrane spanning self-assembled monolayers as model systems for UHV-based studies of cell-penetrating peptides

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

Franz, Johannes; Graham, Daniel J.; Schmüser, Lars

2015-03-01

Biophysical studies of the interaction of peptides with model membranes provide a simple yet effective approach to understand the transport of peptides and peptide based drug carriers across the cell membrane. Therein, the authors discuss the use of self-assembled monolayers fabricated from the full membrane-spanning thiol (FMST) 3-((14-((4'-((5-methyl-1-phenyl-35-(phytanyl)oxy-6,9,12,15,18,21,24,27,30,33,37-undecaoxa-2,3-dithiahenpentacontan-51-yl)oxy)-[1,1'-biphenyl]-4-yl)oxy)tetradecyl)oxy)-2-(phytanyl)oxy glycerol for ultrahigh vacuum (UHV) based experiments. UHV-based methods such as electron spectroscopy and mass spectrometry can provide important information about how peptides bind and interact with membranes, especially with the hydrophobic core of a lipid bilayer. Moreover, near-edge x-ray absorption fine structure spectra and x-ray photoelectron spectroscopy (XPS) data showed thatmore » FMST forms UHV-stable and ordered films on gold. XPS and time of flight secondary ion mass spectrometry depth profiles indicated that a proline-rich amphipathic cell-penetrating peptide, known as sweet arrow peptide is located at the outer perimeter of the model membrane.« less

30 CFR 75.807 - Installation of high-voltage transmission cables.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Installation of high-voltage transmission...-Voltage Distribution § 75.807 Installation of high-voltage transmission cables. [Statutory Provisions] All underground high-voltage transmission cables shall be installed only in regularly inspected air courses and...

High voltage systems (tube-type microwave)/low voltage system (solid-state microwave) power distribution

NASA Technical Reports Server (NTRS)

Nussberger, A. A.; Woodcock, G. R.

1980-01-01

SPS satellite power distribution systems are described. The reference Satellite Power System (SPS) concept utilizes high-voltage klystrons to convert the onboard satellite power from dc to RF for transmission to the ground receiving station. The solar array generates this required high voltage and the power is delivered to the klystrons through a power distribution subsystem. An array switching of solar cell submodules is used to maintain bus voltage regulation. Individual klystron dc voltage conversion is performed by centralized converters. The on-board data processing system performs the necessary switching of submodules to maintain voltage regulation. Electrical power output from the solar panels is fed via switch gears into feeder buses and then into main distribution buses to the antenna. Power also is distributed to batteries so that critical functions can be provided through solar eclipses.

Ultra-high Temperature Emittance Measurements for Space and Missile Applications

NASA Technical Reports Server (NTRS)

Rogers, Jan; Crandall, David

2009-01-01

Advanced modeling and design efforts for many aerospace components require high temperature emittance data. Applications requiring emittance data include propulsion systems, radiators, aeroshells, heatshields/thermal protection systems, and leading edge surfaces. The objective of this work is to provide emittance data at ultra-high temperatures. MSFC has a new instrument for the measurement of emittance at ultra-high temperatures, the Ultra-High Temperature Emissometer System (Ultra-HITEMS). AZ Technology Inc. developed the instrument, designed to provide emittance measurements over the temperature range 700-3500K. The Ultra-HITEMS instrument measures the emittance of samples, heated by lasers, in vacuum, using a blackbody source and a Fourier Transform Spectrometer. Detectors in a Nicolet 6700 FT-IR spectrometer measure emittance over the spectral range of 0.4-25 microns. Emitted energy from the specimen and output from a Mikron M390S blackbody source at the same temperature with matched collection geometry are measured. Integrating emittance over the spectral range yields the total emittance. The ratio provides a direct measure of total hemispherical emittance. Samples are heated using lasers. Optical pyrometry provides temperature data. Optical filters prevent interference from the heating lasers. Data for Inconel 718 show excellent agreement with results from literature and ASTM 835. Measurements taken from levitated spherical specimens provide total hemispherical emittance data; measurements taken from flat specimens mounted in the chamber provide near-normal emittance data. Data from selected characterization studies will be presented. The Ultra-HITEMS technique could advance space and missile technologies by advancing the knowledge base and the technology readiness level for ultra-high temperature materials.

30 CFR 75.810 - High-voltage trailing cables; splices.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-voltage trailing cables; splices. 75.810... § 75.810 High-voltage trailing cables; splices. [Statutory Provisions] In the case of high-voltage cables used as trailing cables, temporary splices shall not be used and all permanent splices shall be...

E-beam high voltage switching power supply

DOEpatents

Shimer, Daniel W.; Lange, Arnold C.

1997-01-01

A high power, solid state power supply is described for producing a controllable, constant high voltage output under varying and arcing loads suitable for powering an electron beam gun or other ion source. The present power supply is most useful for outputs in a range of about 100-400 kW or more. The power supply is comprised of a plurality of discrete switching type dc-dc converter modules, each comprising a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, and an output rectifier for producing a dc voltage at the output of each module. The inputs to the converter modules are fed from a common dc rectifier/filter and are linked together in parallel through decoupling networks to suppress high frequency input interactions. The outputs of the converter modules are linked together in series and connected to the input of the transmission line to the load through a decoupling and line matching network. The dc-dc converter modules are phase activated such that for n modules, each module is activated equally 360.degree./n out of phase with respect to a successive module. The phased activation of the converter modules, combined with the square current waveforms out of the step up transformers, allows the power supply to operate with greatly reduced output capacitance values which minimizes the stored energy available for discharge into an electron beam gun or the like during arcing. The present power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle using simulated voltage feedback signals and voltage feedback loops. Circuitry is also provided for sensing incipient arc currents reflected at the output of the power supply and for simultaneously decoupling the power supply circuitry from the arcing load.

E-beam high voltage switching power supply

DOEpatents

Shimer, D.W.; Lange, A.C.

1997-03-11

A high power, solid state power supply is described for producing a controllable, constant high voltage output under varying and arcing loads suitable for powering an electron beam gun or other ion source. The present power supply is most useful for outputs in a range of about 100-400 kW or more. The power supply is comprised of a plurality of discrete switching type dc-dc converter modules, each comprising a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, and an output rectifier for producing a dc voltage at the output of each module. The inputs to the converter modules are fed from a common dc rectifier/filter and are linked together in parallel through decoupling networks to suppress high frequency input interactions. The outputs of the converter modules are linked together in series and connected to the input of the transmission line to the load through a decoupling and line matching network. The dc-dc converter modules are phase activated such that for n modules, each module is activated equally 360{degree}/n out of phase with respect to a successive module. The phased activation of the converter modules, combined with the square current waveforms out of the step up transformers, allows the power supply to operate with greatly reduced output capacitance values which minimizes the stored energy available for discharge into an electron beam gun or the like during arcing. The present power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle using simulated voltage feedback signals and voltage feedback loops. Circuitry is also provided for sensing incipient arc currents reflected at the output of the power supply and for simultaneously decoupling the power supply circuitry from the arcing load. 7 figs.

Boeing's High Voltage Solar Tile Test Results

NASA Astrophysics Data System (ADS)

Reed, Brian J.; Harden, David E.; Ferguson, Dale C.; Snyder, David B.

2002-10-01

Real concerns of spacecraft charging and experience with solar array augmented electrostatic discharge arcs on spacecraft have minimized the use of high voltages on large solar arrays despite numerous vehicle system mass and efficiency advantages. Boeing's solar tile (patent pending) allows high voltage to be generated at the array without the mass and efficiency losses of electronic conversion. Direct drive electric propulsion and higher power payloads (lower spacecraft weight) will benefit from this design. As future power demand grows, spacecraft designers must use higher voltage to minimize transmission loss and power cable mass for very large area arrays. This paper will describe the design and discuss the successful test of Boeing's 500-Volt Solar Tile in NASA Glenn's Tenney chamber in the Space Plasma Interaction Facility. The work was sponsored by NASA's Space Solar Power Exploratory Research and Technology (SERT) Program and will result in updated high voltage solar array design guidelines being published.

Boeing's High Voltage Solar Tile Test Results

NASA Technical Reports Server (NTRS)

Reed, Brian J.; Harden, David E.; Ferguson, Dale C.; Snyder, David B.

2002-01-01

Real concerns of spacecraft charging and experience with solar array augmented electrostatic discharge arcs on spacecraft have minimized the use of high voltages on large solar arrays despite numerous vehicle system mass and efficiency advantages. Boeing's solar tile (patent pending) allows high voltage to be generated at the array without the mass and efficiency losses of electronic conversion. Direct drive electric propulsion and higher power payloads (lower spacecraft weight) will benefit from this design. As future power demand grows, spacecraft designers must use higher voltage to minimize transmission loss and power cable mass for very large area arrays. This paper will describe the design and discuss the successful test of Boeing's 500-Volt Solar Tile in NASA Glenn's Tenney chamber in the Space Plasma Interaction Facility. The work was sponsored by NASA's Space Solar Power Exploratory Research and Technology (SERT) Program and will result in updated high voltage solar array design guidelines being published.

Conceptual definition of a high voltage power supply test facility

NASA Technical Reports Server (NTRS)

Biess, John J.; Chu, Teh-Ming; Stevens, N. John

1989-01-01

NASA Lewis Research Center is presently developing a 60 GHz traveling wave tube for satellite cross-link communications. The operating voltage for this new tube is - 20 kV. There is concern about the high voltage insulation system and NASA is planning a space station high voltage experiment that will demonstrate both the 60 GHz communications and high voltage electronics technology. The experiment interfaces, requirements, conceptual design, technology issues and safety issues are determined. A block diagram of the high voltage power supply test facility was generated. It includes the high voltage power supply, the 60 GHz traveling wave tube, the communications package, the antenna package, a high voltage diagnostics package and a command and data processor system. The interfaces with the space station and the attached payload accommodations equipment were determined. A brief description of the different subsystems and a discussion of the technology development needs are presented.

Experimental validation of prototype high voltage bushing

NASA Astrophysics Data System (ADS)

Shah, Sejal; Tyagi, H.; Sharma, D.; Parmar, D.; M. N., Vishnudev; Joshi, K.; Patel, K.; Yadav, A.; Patel, R.; Bandyopadhyay, M.; Rotti, C.; Chakraborty, A.

2017-08-01

Prototype High voltage bushing (PHVB) is a scaled down configuration of DNB High Voltage Bushing (HVB) of ITER. It is designed for operation at 50 kV DC to ensure operational performance and thereby confirming the design configuration of DNB HVB. Two concentric insulators viz. Ceramic and Fiber reinforced polymer (FRP) rings are used as double layered vacuum boundary for 50 kV isolation between grounded and high voltage flanges. Stress shields are designed for smooth electric field distribution. During ceramic to Kovar brazing, spilling cannot be controlled which may lead to high localized electrostatic stress. To understand spilling phenomenon and precise stress calculation, quantitative analysis was performed using Scanning Electron Microscopy (SEM) of brazed sample and similar configuration modeled while performing the Finite Element (FE) analysis. FE analysis of PHVB is performed to find out electrical stresses on different areas of PHVB and are maintained similar to DNB HV Bushing. With this configuration, the experiment is performed considering ITER like vacuum and electrical parameters. Initial HV test is performed by temporary vacuum sealing arrangements using gaskets/O-rings at both ends in order to achieve desired vacuum and keep the system maintainable. During validation test, 50 kV voltage withstand is performed for one hour. Voltage withstand test for 60 kV DC (20% higher rated voltage) have also been performed without any breakdown. Successful operation of PHVB confirms the design of DNB HV Bushing. In this paper, configuration of PHVB with experimental validation data is presented.

Ultra-high aspect ratio copper nanowires as transparent conductive electrodes for dye sensitized solar cells

NASA Astrophysics Data System (ADS)

Zhu, Zhaozhao; Mankowski, Trent; Shikoh, Ali Sehpar; Touati, Farid; Benammar, Mohieddine A.; Mansuripur, Masud; Falco, Charles M.

2016-09-01

We report the synthesis of ultra-high aspect ratio copper nanowires (CuNW) and fabrication of CuNW-based transparent conductive electrodes (TCE) with high optical transmittance (>80%) and excellent sheet resistance (Rs <30 Ω/sq). These CuNW TCEs are subsequently hybridized with aluminum-doped zinc oxide (AZO) thin-film coatings, or platinum thin film coatings, or nickel thin-film coatings. Our hybrid transparent electrodes can replace indium tin oxide (ITO) films in dye-sensitized solar cells (DSSCs) as either anodes or cathodes. We highlight the challenges of integrating bare CuNWs into DSSCs, and demonstrate that hybridization renders the solar cell integrations feasible. The CuNW/AZO-based DSSCs have reasonably good open-circuit voltage (Voc = 720 mV) and short-circuit current-density (Jsc = 0.96 mA/cm2), which are comparable to what is obtained with an ITO-based DSSC fabricated with a similar process. Our CuNW-Ni based DSSCs exhibit a good open-circuit voltage (Voc = 782 mV) and a decent short-circuit current (Jsc = 3.96 mA/cm2), with roughly 1.5% optical-to-electrical conversion efficiency.

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.

30 CFR 75.811 - High-voltage underground equipment; grounding.

Code of Federal Regulations, 2010 CFR

2010-07-01

...-voltage equipment supplying power to such equipment receiving power from resistance grounded systems shall... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-voltage underground equipment; grounding... COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Underground High-Voltage...

Ultra-Smooth ZnS Films Grown on Silicon via Pulsed Laser Deposition

NASA Astrophysics Data System (ADS)

Reidy, Christopher; Tate, Janet

2011-10-01

Ultra-smooth, high quality ZnS films were grown on (100) and (111) oriented Si wafers via pulsed laser deposition with a KrF excimer laser in UHV (10-9 Torr). The resultant films were examined with optical spectroscopy, electron diffraction, and electron probe microanalysis. The films have an rms roughness of ˜1.5 nm, and the film stoichiometry is approximately Zn:S :: 1:0.87. Additionally, each film exhibits an optical interference pattern which is not a function of probing location on the sample, indicating excellent film thickness uniformity. Motivation for high-quality ZnS films comes from a proposed experiment to measure carrier amplification via impact ionization at the boundary between a wide-gap and a narrow-gap semiconductor. If excited charge carriers in a sufficiently wide-gap harvester can be extracted into a narrow-gap host material, impact ionization may occur. We seek near-perfect interfaces between ZnS, with a direct gap between 3.3 and 3.7 eV, and Si, with an indirect gap of 1.1 eV.

High voltage photovoltaic power converter

DOEpatents

Haigh, Ronald E.; Wojtczuk, Steve; Jacobson, Gerard F.; Hagans, Karla G.

2001-01-01

An array of independently connected photovoltaic cells on a semi-insulating substrate contains reflective coatings between the cells to enhance efficiency. A uniform, flat top laser beam profile is illuminated upon the array to produce electrical current having high voltage. An essentially wireless system includes a laser energy source being fed through optic fiber and cast upon the photovoltaic cell array to prevent stray electrical signals prior to use of the current from the array. Direct bandgap, single crystal semiconductor materials, such as GaAs, are commonly used in the array. Useful applications of the system include locations where high voltages are provided to confined spaces such as in explosive detonation, accelerators, photo cathodes and medical appliances.

Formal thought disorder in people at ultra-high risk of psychosis

PubMed Central

Weinstein, Sara; Stahl, Daniel; Day, Fern; Valmaggia, Lucia; Rutigliano, Grazia; De Micheli, Andrea; Fusar-Poli, Paolo; McGuire, Philip

2017-01-01

Background Formal thought disorder is a cardinal feature of psychosis. However, the extent to which formal thought disorder is evident in ultra-high-risk individuals and whether it is linked to the progression to psychosis remains unclear. Aims Examine the severity of formal thought disorder in ultra-high-risk participants and its association with future psychosis. Method The Thought and Language Index (TLI) was used to assess 24 ultra-high-risk participants, 16 people with first-episode psychosis and 13 healthy controls. Ultra-high-risk individuals were followed up for a mean duration of 7 years (s.d.=1.5) to determine the relationship between formal thought disorder at baseline and transition to psychosis. Results TLI scores were significantly greater in the ultra-high-risk group compared with the healthy control group (effect size (ES)=1.2), but lower than in people with first-episode psychosis (ES=0.8). Total and negative TLI scores were higher in ultra-high-risk individuals who developed psychosis, but this was not significant. Combining negative TLI scores with attenuated psychotic symptoms and basic symptoms predicted transition to psychosis (P=0.04; ES=1.04). Conclusions TLI is beneficial in evaluating formal thought disorder in ultra-high-risk participants, and complements existing instruments for the evaluation of psychopathology in this group. Declaration of interests None. Copyright and usage © The Royal College of Psychiatrists 2017. This is an open access article distributed under the terms of the Creative Commons Non-Commercial, No Derivatives (CC BY-NC-ND) license. PMID:28713586

Switch contact device for interrupting high current, high voltage, AC and DC circuits

DOEpatents

Via, Lester C.; Witherspoon, F. Douglas; Ryan, John M.

2005-01-04

A high voltage switch contact structure capable of interrupting high voltage, high current AC and DC circuits. The contact structure confines the arc created when contacts open to the thin area between two insulating surfaces in intimate contact. This forces the arc into the shape of a thin sheet which loses heat energy far more rapidly than an arc column having a circular cross-section. These high heat losses require a dramatic increase in the voltage required to maintain the arc, thus extinguishing it when the required voltage exceeds the available voltage. The arc extinguishing process with this invention is not dependent on the occurrence of a current zero crossing and, consequently, is capable of rapidly interrupting both AC and DC circuits. The contact structure achieves its high performance without the use of sulfur hexafluoride.

Advanced Photonic Sensors Enabled by Semiconductor Bonding

DTIC Science & Technology

2010-05-31

a dry scroll backing pump to maintain the high differential pressure between the UV gun and the sample/analysis chamber. We also replaced the...semiconductor materials in an ultra-high vacuum (UHV) environment where the properties of the interface can be controlled with atomic-level precision. Such...year research program, we designed and constructed a unique system capable of fusion bonding two wafers in an ultra-high vacuum environment. This system

High-voltage subnanosecond dielectric breakdown

NASA Astrophysics Data System (ADS)

Mankowski, John Jerome

Current interests in ultrawideband radar sources are in the microwave regime, which correspond to voltage pulse risetimes less than a nanosecond. Some new sources, including the Phillips Laboratory Hindenberg series of hydrogen gas switched pulsers use hydrogen at hundreds of atmospheres of pressure in the switch. Unfortunately, the published data of electrical breakdown of gas and liquid media at these time lengths are relatively scarce. A study was conducted on the electrical breakdown properties of liquid and gas dielectrics at subnanosecond and nanoseconds. Two separate voltage sources with pulse risetimes less than 400 ps were developed. Diagnostic probes were designed and tested for their capability of detecting high voltage pulses at these fast risetimes. A thorough investigation into E-field strengths of liquid and gas dielectrics at breakdown times ranging from 0.4 to 5 ns was performed. The voltage polarity dependence on breakdown strength is observed. Streak camera images of streamer formation were taken. The effect of ultraviolet radiation, incident upon the gap, on statistical lag time was determined.

Suppression of surface segregation of the phosphorous δ-doping layer by insertion of an ultra-thin silicon layer for ultra-shallow Ohmic contacts on n-type germanium

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

Yamada, Michihiro; Uematsu, Masashi; Itoh, Kohei M., E-mail: kitoh@appi.keio.ac.jp

2015-09-28

We demonstrate the formation of abrupt phosphorus (P) δ-doping profiles in germanium (Ge) by the insertion of ultra-thin silicon (Si) layers. The Si layers at the δ-doping region significantly suppress the surface segregation of P during the molecular beam epitaxial growth of Ge and high-concentration active P donors are confined within a few nm of the initial doping position. The current-voltage characteristics of the P δ-doped layers with Si insertion show excellent Ohmic behaviors with low enough resistivity for ultra-shallow Ohmic contacts on n-type Ge.

A Systematic Multi-Time Scale Solution for Regional Power Grid Operation

NASA Astrophysics Data System (ADS)

Zhu, W. J.; Liu, Z. G.; Cheng, T.; Hu, B. Q.; Liu, X. Z.; Zhou, Y. F.

2017-10-01

Many aspects need to be taken into consideration in a regional grid while making schedule plans. In this paper, a systematic multi-time scale solution for regional power grid operation considering large scale renewable energy integration and Ultra High Voltage (UHV) power transmission is proposed. In the time scale aspect, we discuss the problem from month, week, day-ahead, within-day to day-behind, and the system also contains multiple generator types including thermal units, hydro-plants, wind turbines and pumped storage stations. The 9 subsystems of the scheduling system are described, and their functions and relationships are elaborated. The proposed system has been constructed in a provincial power grid in Central China, and the operation results further verified the effectiveness of the system.

Ultra High Energy Cosmic Rays: Strangelets?

NASA Astrophysics Data System (ADS)

Xu, Ren-Xin; Wu, Fei

2003-06-01

The conjecture that ultra-high-energy cosmic rays (UHECRs) are actually strangelets is discussed. Besides the reason that strangelets can do as cosmic rays beyond the Greisen-Zatsepin-Kuzmin-cutoff, another argument to support the conjecture is addressed by the study of formation of TeV-scale microscopic black holes when UHECRs bombarding bare strange stars. It is proposed that the exotic quark surface of a bare strange star could be an effective astro-laboratory in the investigations of the extra dimensions and of the detection of ultra-high-energy neutrino fluxes. The flux of neutrinos (and other point-like particles) with energy larger than 2.3×1020 eV could be expected to be smaller than 10-26 cm-2 s-1 if there are two extra spatial dimensions.

PV source based high voltage gain current fed converter

NASA Astrophysics Data System (ADS)

Saha, Soumya; Poddar, Sahityika; Chimonyo, Kudzai B.; Arunkumar, G.; Elangovan, D.

2017-11-01

This work involves designing and simulation of a PV source based high voltage gain, current fed converter. It deals with an isolated DC-DC converter which utilizes boost converter topology. The proposed converter is capable of high voltage gain and above all have very high efficiency levels as proved by the simulation results. The project intends to produce an output of 800 V dc from a 48 V dc input. The simulation results obtained from PSIM application interface were used to analyze the performance of the proposed converter. Transformer used in the circuit steps up the voltage as well as to provide electrical isolation between the low voltage and high voltage side. Since the converter involves high switching frequency of 100 kHz, ultrafast recovery diodes are employed in the circuitry. The major application of the project is for future modeling of solar powered electric hybrid cars.

Review of adult electrical burn injury outcomes worldwide: An analysis of low- voltage versus high-voltage electrical injury

PubMed Central

Shih, Jessica G; Shahrokhi, Shahriar; Jeschke, Marc G

2016-01-01

Objective To review low-voltage versus high-voltage electrical burn complications in adults, and to identify novel areas that are not recognized to improve outcomes. Methods An extensive literature search on electrical burn injuries was performed using OVID Medline, PubMed and EMBASE databases from 1946–2015. Studies relating to outcomes of electrical injury in the adult population (≥18 years of age) were included in the study. Results Forty-one single-institution publications with a total of 5485 electrical injury patients were identified and included in the present study. 18.0% of these patients were low-voltage injuries (LVI), 38.3% high-voltage injuries (HVI) and 43.7% with voltage not otherwise specified (NOS). Forty-four percent of studies did not characterize outcomes according to low versus high-voltage injuries. Reported outcomes include surgical, medical, post-traumatic, and other (long-term/psychological/rehabilitative), all of which report greater incidence rates in HVI compared to LVI. Only two studies report on psychological outcomes such as post-traumatic stress disorder. Mortality from electrical injuries are 2.6% in LVI, 5.2% in HVI and 3.7% in NOS. Coroner’s reports reveal a ratio of 2.4:1 for deaths caused by low-voltage injury compared to high voltage-injury. Conclusions High-voltage injuries lead to greater morbidity and mortality than low-voltage injuries. However, the results of the coroner’s reports suggest that immediate mortality from low-voltage injury may be underestimated. Furthermore, based on the data of this analysis we conclude that the majority of studies report electrical injury outcomes, however, the majority of them do not analyze complications by low versus high voltage and often lack long-term psychological and rehabilitation outcomes post-electrical injury indicating that a variety of central aspects are not being evaluated or assessed. PMID:27359191

30 CFR 77.804 - High-voltage trailing cables; minimum design requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-voltage trailing cables; minimum design... OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.804 High-voltage trailing cables; minimum design requirements. (a) High-voltage trailing cables used in resistance grounded systems shall be...

30 CFR 77.804 - High-voltage trailing cables; minimum design requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false High-voltage trailing cables; minimum design... OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.804 High-voltage trailing cables; minimum design requirements. (a) High-voltage trailing cables used in resistance grounded systems shall be...

30 CFR 77.804 - High-voltage trailing cables; minimum design requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false High-voltage trailing cables; minimum design... OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.804 High-voltage trailing cables; minimum design requirements. (a) High-voltage trailing cables used in resistance grounded systems shall be...

30 CFR 77.804 - High-voltage trailing cables; minimum design requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false High-voltage trailing cables; minimum design... OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.804 High-voltage trailing cables; minimum design requirements. (a) High-voltage trailing cables used in resistance grounded systems shall be...

Technology breakthroughs in high performance metal-oxide-semiconductor devices for ultra-high density, low power non-volatile memory applications

NASA Astrophysics Data System (ADS)

Hong, Augustin Jinwoo

Non-volatile memory devices have attracted much attention because data can be retained without power consumption more than a decade. Therefore, non-volatile memory devices are essential to mobile electronic applications. Among state of the art non-volatile memory devices, NAND flash memory has earned the highest attention because of its ultra-high scalability and therefore its ultra-high storage capacity. However, human desire as well as market competition requires not only larger storage capacity but also lower power consumption for longer battery life time. One way to meet this human desire and extend the benefits of NAND flash memory is finding out new materials for storage layer inside the flash memory, which is called floating gate in the state of the art flash memory device. In this dissertation, we study new materials for the floating gate that can lower down the power consumption and increase the storage capacity at the same time. To this end, we employ various materials such as metal nanodot, metal thin film and graphene incorporating complementary-metal-oxide-semiconductor (CMOS) compatible processes. Experimental results show excellent memory effects at relatively low operating voltages. Detailed physics and analysis on experimental results are discussed. These new materials for data storage can be promising candidates for future non-volatile memory application beyond the state of the art flash technologies.

The high voltage homopolar generator

NASA Astrophysics Data System (ADS)

Price, J. H.; Gully, J. H.; Driga, M. D.

1986-11-01

System and component design features of proposed high voltage homopolar generator (HVHPG) are described. The system is to have an open circuit voltage of 500 V, a peak output current of 500 kA, 3.25 MJ of stored inertial energy and possess an average magnetic-flux density of 5 T. Stator assembly components are discussed, including the stator, mount structure, hydrostatic bearings, main and motoring brushgears and rotor. Planned operational procedures such as monitoring the rotor to full speed and operation with a superconducting field coil are delineated.

Molecular electronics--resonant transport through single molecules.

PubMed

Lörtscher, Emanuel; Riel, Heike

2010-01-01

The mechanically controllable break-junction technique (MCBJ) enables us to investigate charge transport through an individually contacted and addressed molecule in ultra-high vacuum (UHV) environment at variable temperature ranging from room temperature down to 4 K. Using a statistical measurement and analysis approach, we acquire current-voltage (I-V) characteristics during the repeated formation, manipulation, and breaking of a molecular junction. At low temperatures, voltages accessing the first molecular orbitals in resonance can be applied, providing spectroscopic information about the junction's energy landscape, in particular about the molecular level alignment in respect to the Fermi energy of the electrodes. Thereby, we can investigate the non-linear transport properties of various types of functional molecules and explore their potential use as functional building blocks for future nano-electronics. An example will be given by the reversible and controllable switching between two distinct conductive states of a single molecule. As a proof-of-principle for functional molecular devices, a single-molecule memory element will be demonstrated.

Low Power, High Voltage Power Supply with Fast Rise/Fall Time

NASA Technical Reports Server (NTRS)

Bearden, Douglas B. (Inventor)

2007-01-01

A low power, high voltage power supply system includes a high voltage power supply stage and a preregulator for programming the power supply stage so as to produce an output voltage which is a predetermined fraction of a desired voltage level. The power supply stage includes a high voltage, voltage doubler stage connected to receive the output voltage from the preregulator and for, when activated, providing amplification of the output voltage to the desired voltage level. A first feedback loop is connected between the output of the preregulator and an input of the preregulator while a second feedback loop is connected between the output of the power supply stage and the input of the preregulator.

Low power, high voltage power supply with fast rise/fall time

NASA Technical Reports Server (NTRS)

Bearden, Douglas B. (Inventor)

2007-01-01

A low power, high voltage power supply system includes a high voltage power supply stage and a preregulator for programming the power supply stage so as to produce an output voltage which is a predetermined fraction of a desired voltage level. The power supply stage includes a high voltage, voltage doubler stage connected to receive the output voltage from the preregulator and for, when activated, providing amplification of the output voltage to the desired voltage level. A first feedback loop is connected between the output of the preregulator and an input of the preregulator while a second feedback loop is connected between the output of the power supply stage and the input of the preregulator.

An ultra-thin, un-doped NiO hole transporting layer of highly efficient (16.4%) organic-inorganic hybrid perovskite solar cells.

PubMed

Seo, Seongrok; Park, Ik Jae; Kim, Myungjun; Lee, Seonhee; Bae, Changdeuck; Jung, Hyun Suk; Park, Nam-Gyu; Kim, Jin Young; Shin, Hyunjung

2016-06-02

NiO is a wide band gap p-type oxide semiconductor and has potential for applications in solar energy conversion as a hole-transporting layer (HTL). It also has good optical transparency and high chemical stability, and the capability of aligning the band edges to the perovskite (CH3NH3PbI3) layers. Ultra-thin and un-doped NiO films with much less absorption loss were prepared by atomic layer deposition (ALD) with highly precise control over thickness without any pinholes. Thin enough (5-7.5 nm in thickness) NiO films with the thickness of few time the Debye length (LD = 1-2 nm for NiO) show enough conductivities achieved by overlapping space charge regions. The inverted planar perovskite solar cells with NiO films as HTLs exhibited the highest energy conversion efficiency of 16.40% with high open circuit voltage (1.04 V) and fill factor (0.72) with negligible current-voltage hysteresis.

Fusion: ultra-high-speed and IR image sensors

NASA Astrophysics Data System (ADS)

Etoh, T. Goji; Dao, V. T. S.; Nguyen, Quang A.; Kimata, M.

2015-08-01

Most targets of ultra-high-speed video cameras operating at more than 1 Mfps, such as combustion, crack propagation, collision, plasma, spark discharge, an air bag at a car accident and a tire under a sudden brake, generate sudden heat. Researchers in these fields require tools to measure the high-speed motion and heat simultaneously. Ultra-high frame rate imaging is achieved by an in-situ storage image sensor. Each pixel of the sensor is equipped with multiple memory elements to record a series of image signals simultaneously at all pixels. Image signals stored in each pixel are read out after an image capturing operation. In 2002, we developed an in-situ storage image sensor operating at 1 Mfps 1). However, the fill factor of the sensor was only 15% due to a light shield covering the wide in-situ storage area. Therefore, in 2011, we developed a backside illuminated (BSI) in-situ storage image sensor to increase the sensitivity with 100% fill factor and a very high quantum efficiency 2). The sensor also achieved a much higher frame rate,16.7 Mfps, thanks to the wiring on the front side with more freedom 3). The BSI structure has another advantage that it has less difficulties in attaching an additional layer on the backside, such as scintillators. This paper proposes development of an ultra-high-speed IR image sensor in combination of advanced nano-technologies for IR imaging and the in-situ storage technology for ultra-highspeed imaging with discussion on issues in the integration.

A high-voltage supply used on miniaturized RLG

NASA Astrophysics Data System (ADS)

Miao, Zhifei; Fan, Mingming; Wang, Yuepeng; Yin, Yan; Wang, Dongmei

2016-01-01

A high voltage power supply used in laser gyro is proposed in this paper. The power supply which uses a single DC 15v input and fly-back topology is adopted in the main circuit. The output of the power supply achieve high to 3.3kv voltage in order to light the RLG. The PFM control method is adopted to realize the rapid switching between the high voltage state and the maintain state. The resonant chip L6565 is used to achieve the zero voltage switching(ZVS), so the consumption is reduced and the power efficiency is improved more than 80%. A special circuit is presented in the control portion to ensure symmetry of the two RLG's arms current. The measured current accuracy is higher than 5‰ and the current symmetry of the two RLG's arms up to 99.2%.

30 CFR 75.802 - Protection of high-voltage circuits extending underground.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Protection of high-voltage circuits extending...-Voltage Distribution § 75.802 Protection of high-voltage circuits extending underground. (a) Except as provided in paragraph (b) of this section, high-voltage circuits extending underground and supplying...

30 CFR 75.802 - Protection of high-voltage circuits extending underground.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Protection of high-voltage circuits extending...-Voltage Distribution § 75.802 Protection of high-voltage circuits extending underground. (a) Except as provided in paragraph (b) of this section, high-voltage circuits extending underground and supplying...

30 CFR 75.802 - Protection of high-voltage circuits extending underground.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Protection of high-voltage circuits extending...-Voltage Distribution § 75.802 Protection of high-voltage circuits extending underground. (a) Except as provided in paragraph (b) of this section, high-voltage circuits extending underground and supplying...

Oxidatively stable fluorinated sulfone electrolytes for high voltage high energy lithium-ion batteries

DOE PAGES

Su, Chi -Cheung; He, Meinan; Redfern, Paul C.; ...

2017-03-16

New fluorinated sulfones were synthesized and evaluated in high voltage lithium-ion batteries using LiNi 0.5Mn 1.5O 4 (LNMO) cathode. Fluorinated sulfones with an α-trifluoromethyl group exhibit enhanced oxidation stability, reduced viscosity and superior separator wettability as compared to their non-fluorinated counterparts. Finally, the improved performance in high voltage cells makes it a promising high voltage electrolyte for 5-V lithium-ion chemistry.

High voltage generator

DOEpatents

Schwemin, A. J.

1959-03-17

A generator for producing relatively large currents at high voltages is described. In general, the invention comprises a plurality of capacitors connected in series by a plurality of switches alternately disposed with the capacitors. The above-noted circuit is mounted for movement with respect to contact members and switch closure means so that a load device and power supply are connected across successive numbers of capacitors, while the other capacitors are successively charged with the same power supply.

HIGH VOLTAGE GENERATOR

DOEpatents

Schwemin, A.J.

1959-03-17

A generator is presented for producing relatively large currents at high voltages. In general, the invention comprises a plurality of capacitors connected in series by a plurality of switches alternately disposed with the capacitors. The circuit is mounted for movement with respect to contact members and switch closure means so that a load device and power supply are connected across successive numbers of capacitors, while the other capacitors are successively charged with the same power supply.

Optical control system for high-voltage terminals

DOEpatents

Bicek, John J.

1978-01-01

An optical control system for the control of devices in the terminal of an electrostatic accelerator includes a laser that is modulated by a series of preselected codes produced by an encoder. A photodiode receiver is placed in the laser beam at the high-voltage terminal of an electrostatic accelerator. A decoder connected to the photodiode decodes the signals to provide control impulses for a plurality of devices at the high voltage of the terminal.

21 CFR 892.1700 - Diagnostic x-ray high voltage generator.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Diagnostic x-ray high voltage generator. 892.1700... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1700 Diagnostic x-ray high voltage generator. (a) Identification. A diagnostic x-ray high voltage generator is a device that is intended to...

21 CFR 892.1700 - Diagnostic x-ray high voltage generator.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Diagnostic x-ray high voltage generator. 892.1700... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1700 Diagnostic x-ray high voltage generator. (a) Identification. A diagnostic x-ray high voltage generator is a device that is intended to...

21 CFR 892.1700 - Diagnostic x-ray high voltage generator.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Diagnostic x-ray high voltage generator. 892.1700... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1700 Diagnostic x-ray high voltage generator. (a) Identification. A diagnostic x-ray high voltage generator is a device that is intended to...

21 CFR 892.1700 - Diagnostic x-ray high voltage generator.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Diagnostic x-ray high voltage generator. 892.1700... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1700 Diagnostic x-ray high voltage generator. (a) Identification. A diagnostic x-ray high voltage generator is a device that is intended to...

21 CFR 892.1700 - Diagnostic x-ray high voltage generator.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Diagnostic x-ray high voltage generator. 892.1700... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1700 Diagnostic x-ray high voltage generator. (a) Identification. A diagnostic x-ray high voltage generator is a device that is intended to...

Voltage assisted asymmetric nanoscale wear on ultra-smooth diamond like carbon thin films at high sliding speeds

PubMed Central

Rajauria, Sukumar; Schreck, Erhard; Marchon, Bruno

2016-01-01

The understanding of tribo- and electro-chemical phenomenons on the molecular level at a sliding interface is a field of growing interest. Fundamental chemical and physical insights of sliding surfaces are crucial for understanding wear at an interface, particularly for nano or micro scale devices operating at high sliding speeds. A complete investigation of the electrochemical effects on high sliding speed interfaces requires a precise monitoring of both the associated wear and surface chemical reactions at the interface. Here, we demonstrate that head-disk interface inside a commercial magnetic storage hard disk drive provides a unique system for such studies. The results obtained shows that the voltage assisted electrochemical wear lead to asymmetric wear on either side of sliding interface. PMID:27150446

Voltage assisted asymmetric nanoscale wear on ultra-smooth diamond like carbon thin films at high sliding speeds

NASA Astrophysics Data System (ADS)

Rajauria, Sukumar; Schreck, Erhard; Marchon, Bruno

2016-05-01

The understanding of tribo- and electro-chemical phenomenons on the molecular level at a sliding interface is a field of growing interest. Fundamental chemical and physical insights of sliding surfaces are crucial for understanding wear at an interface, particularly for nano or micro scale devices operating at high sliding speeds. A complete investigation of the electrochemical effects on high sliding speed interfaces requires a precise monitoring of both the associated wear and surface chemical reactions at the interface. Here, we demonstrate that head-disk interface inside a commercial magnetic storage hard disk drive provides a unique system for such studies. The results obtained shows that the voltage assisted electrochemical wear lead to asymmetric wear on either side of sliding interface.

Modular High Voltage Power Supply

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

Newell, Matthew R.

The goal of this project is to develop a modular high voltage power supply that will meet the needs of safeguards applications and provide a modular plug and play supply for use with standard electronic racks.

A compact 100 kV high voltage glycol capacitor.

PubMed

Wang, Langning; Liu, Jinliang; Feng, Jiahuai

2015-01-01

A high voltage capacitor is described in this paper. The capacitor uses glycerol as energy storage medium, has a large capacitance close to 1 nF, can hold off voltages of up to 100 kV for μs charging time. Allowing for low inductance, the capacitor electrode is designed as coaxial structure, which is different from the common structure of the ceramic capacitor. With a steady capacitance at different frequencies and a high hold-off voltage of up to 100 kV, the glycol capacitor design provides a potential substitute for the ceramic capacitors in pulse-forming network modulator to generate high voltage pulses with a width longer than 100 ns.

30 CFR 77.704-2 - Repairs to energized high-voltage lines.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Repairs to energized high-voltage lines. 77.704... UNDERGROUND COAL MINES Grounding § 77.704-2 Repairs to energized high-voltage lines. An energized high-voltage... repairs will be performed on power circuits with a phase-to-phase nominal voltage no greater than 15,000...

[Extreme (complicated, ultra-high) refractive errors: terminological misconceptions!?

PubMed

Avetisov, S E

2018-01-01

The article reviews development mechanisms of different refractive errors accompanied by marked defocus of light rays reaching the retina. Terminology used for such ametropias includes terms extreme, ultra-high and complicated. Justification of their usage for primary ametropias, whose symptom complex is based on changes in axial eye length, is an ongoing discussion. To comply with thesaurus definitions of 'diagnosis' and 'pathogenesis', to characterize refractive and anatomical-functional disorders in patients with primary ametropias it is proposed to use the terms 'hyperaxial and hypoaxial syndromes' with elaboration of specific symptoms instead of such expressions as extreme (ultra-high) myopia and hypermetropia.

Ultra-long high-sensitivity Φ-OTDR for high spatial resolution intrusion detection of pipelines.

PubMed

Peng, Fei; Wu, Han; Jia, Xin-Hong; Rao, Yun-Jiang; Wang, Zi-Nan; Peng, Zheng-Pu

2014-06-02

An ultra-long phase-sensitive optical time domain reflectometry (Φ-OTDR) that can achieve high-sensitivity intrusion detection over 131.5km fiber with high spatial resolution of 8m is presented, which is the longest Φ-OTDR reported to date, to the best of our knowledge. It is found that the combination of distributed Raman amplification with heterodyne detection can extend the sensing distance and enhances the sensitivity substantially, leading to the realization of ultra-long Φ-OTDR with high sensitivity and spatial resolution. Furthermore, the feasibility of applying such an ultra-long Φ-OTDR to pipeline security monitoring is demonstrated and the features of intrusion signal can be extracted with improved SNR by using the wavelet detrending/denoising method proposed.

System for instrumenting and manipulating apparatuses in high voltage

DOEpatents

Jordan, Kevin

2016-06-07

A system for energizing, operating and manipulating apparatuses in high voltage systems. The system uses a dielectric gas such as SF.sub.6 as a driving power supply for a pneumatic motor which ultimately charges a battery or other energy storage device. The stored energy can then be used for instrumentation equipment, or to power any electrical equipment, in the high voltage deck. The accompanying method provides for the use of the SF6 system for operating an electrical device in a high-voltage environment.

Analysis of trace halocarbon contaminants in ultra high purity helium

NASA Technical Reports Server (NTRS)

Fewell, Larry L.

1994-01-01

This study describes the analysis of ultra high purity helium. Purification studies were conducted and containment removal was effected by the utilization of solid adsorbent purge-trap systems at cryogenic temperatures. Volatile organic compounds in ultra high purity helium were adsorbed on a solid adsorbent-cryogenic trap, and thermally desorbed trace halocarbon and other contaminants were analyzed by combined gas chromatography-mass spectrometry.

A quick response four decade logarithmic high-voltage stepping supply

NASA Technical Reports Server (NTRS)

Doong, H.

1978-01-01

An improved high-voltage stepping supply, for space instrumentation is described where low power consumption and fast settling time between steps are required. The high-voltage stepping supply, utilizing an average power of 750 milliwatts, delivers a pair of mirror images with 64 level logarithmic outputs. It covers a four decade range of + or - 2500 to + or - 0.29 volts having an output stability of + or - 0.5 percent or + or - 20 millivolts for all line load and temperature variations. The supply provides a typical step setting time of 1 millisecond with 100 microseconds for the lower two decades. The versatile design features of the high-voltage stepping supply provides a quick response staircase generator as described or a fixed voltage with the option to change levels as required over large dynamic ranges without circuit modifications. The concept can be implemented up to + or - 5000 volts. With these design features, the high-voltage stepping supply should find numerous applications where charged particle detection, electro-optical systems, and high voltage scientific instruments are used.

High voltage electrical amplifier having a short rise time

DOEpatents

Christie, David J.; Dallum, Gregory E.

1991-01-01

A circuit, comprising an amplifier and a transformer is disclosed that produces a high power pulse having a fast response time, and that responds to a digital control signal applied through a digital-to-analog converter. The present invention is suitable for driving a component such as an electro-optic modulator with a voltage in the kilovolt range. The circuit is stable at high frequencies and during pulse transients, and its impedance matching circuit matches the load impedance with the output impedance. The preferred embodiment comprises an input stage compatible with high-speed semiconductor components for amplifying the voltage of the input control signal, a buffer for isolating the input stage from the output stage; and a plurality of current amplifiers connected to the buffer. Each current amplifier is connected to a field effect transistor (FET), which switches a high voltage power supply to a transformer which then provides an output terminal for driving a load. The transformer comprises a plurality of transmission lines connected to the FETs and the load. The transformer changes the impedance and voltage of the output. The preferred embodiment also comprises a low voltage power supply for biasing the FETs at or near an operational voltage.

Depth-resolved ultra-violet spectroscopic photo current-voltage measurements for the analysis of AlGaN/GaN high electron mobility transistor epilayer deposited on Si

NASA Astrophysics Data System (ADS)

Ozden, Burcu; Yang, Chungman; Tong, Fei; Khanal, Min P.; Mirkhani, Vahid; Sk, Mobbassar Hassan; Ahyi, Ayayi Claude; Park, Minseo

2014-10-01

We have demonstrated that the depth-dependent defect distribution of the deep level traps in the AlGaN/GaN high electron mobility transistor (HEMT) epi-structures can be analyzed by using the depth-resolved ultra-violet (UV) spectroscopic photo current-voltage (IV) (DR-UV-SPIV). It is of great importance to analyze deep level defects in the AlGaN/GaN HEMT structure, since it is recognized that deep level defects are the main source for causing current collapse phenomena leading to reduced device reliability. The AlGaN/GaN HEMT epi-layers were grown on a 6 in. Si wafer by metal-organic chemical vapor deposition. The DR-UV-SPIV measurement was performed using a monochromatized UV light illumination from a Xe lamp. The key strength of the DR-UV-SPIV is its ability to provide information on the depth-dependent electrically active defect distribution along the epi-layer growth direction. The DR-UV-SPIV data showed variations in the depth-dependent defect distribution across the wafer. As a result, rapid feedback on the depth-dependent electrical homogeneity of the electrically active defect distribution in the AlGaN/GaN HEMT epi-structure grown on a Si wafer with minimal sample preparation can be elucidated from the DR-UV-SPIV in combination with our previously demonstrated spectroscopic photo-IV measurement with the sub-bandgap excitation.

30 CFR 18.53 - High-voltage longwall mining systems.

Code of Federal Regulations, 2012 CFR

2012-07-01

... and Design Requirements § 18.53 High-voltage longwall mining systems. (a) In each high-voltage motor...-interrupting devices must be designed and installed to prevent automatic reclosure. (d) Transformers with high... “open” position; (iv) When located in an explosion-proof enclosure, the device must be designed and...

30 CFR 18.53 - High-voltage longwall mining systems.

Code of Federal Regulations, 2010 CFR

2010-07-01

... and Design Requirements § 18.53 High-voltage longwall mining systems. (a) In each high-voltage motor...-interrupting devices must be designed and installed to prevent automatic reclosure. (d) Transformers with high... “open” position; (iv) When located in an explosion-proof enclosure, the device must be designed and...

30 CFR 18.53 - High-voltage longwall mining systems.

Code of Federal Regulations, 2014 CFR

2014-07-01

... and Design Requirements § 18.53 High-voltage longwall mining systems. (a) In each high-voltage motor...-interrupting devices must be designed and installed to prevent automatic reclosure. (d) Transformers with high... “open” position; (iv) When located in an explosion-proof enclosure, the device must be designed and...

30 CFR 18.53 - High-voltage longwall mining systems.

Code of Federal Regulations, 2013 CFR

2013-07-01

... and Design Requirements § 18.53 High-voltage longwall mining systems. (a) In each high-voltage motor...-interrupting devices must be designed and installed to prevent automatic reclosure. (d) Transformers with high... “open” position; (iv) When located in an explosion-proof enclosure, the device must be designed and...

30 CFR 18.53 - High-voltage longwall mining systems.

Code of Federal Regulations, 2011 CFR

2011-07-01

... and Design Requirements § 18.53 High-voltage longwall mining systems. (a) In each high-voltage motor...-interrupting devices must be designed and installed to prevent automatic reclosure. (d) Transformers with high... “open” position; (iv) When located in an explosion-proof enclosure, the device must be designed and...

Ultra-High Surface Speed for Metal Removal, Artillery Shell

DTIC Science & Technology

1981-07-01

TECHNICAL LIBRARY "y/a^^cr^ AD-E400 660 CONTRACTOR REPORT ARLCD-CR- 81019 ULTRA-HIGH SURFACE SPEED FOR METAL REMOVAL, ARTILLERY SHELL RICHARD F...Report ARLCD-CR- 81019 2. GOVT ACCESSION NO. 3. RECIPIENT’S CATALOG NUMBER 4. TITLE (and Subtitle) ULTRA-HIGH SURFACE SPEED FOR METAL...UNIT* tuiPPtO 1 MIL -STD-43CA i, ASTM A-274-64 EF A1SI~1340 SEHI FIN FORGING STEEL 6 RC SQ ■ IP 120093* a LIFTS 38 PCS

30 CFR 75.705 - Work on high-voltage lines; deenergizing and grounding.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Work on high-voltage lines; deenergizing and... Work on high-voltage lines; deenergizing and grounding. [Statutory Provisions] High-voltage lines, both..., except that repairs may be permitted, in the case of energized surface high-voltage lines, if such...

Ultra-low noise supercontinuum source for ultra-high resolution optical coherence tomography at 1300 nm

NASA Astrophysics Data System (ADS)

Gonzalo, I. B.; Maria, M.; Engelsholm, R. D.; Feuchter, T.; Leick, L.; Moselund, P. M.; Podoleanu, A.; Bang, O.

2018-02-01

Supercontinuum (SC) sources are of great interest for many applications due to their ultra-broad optical bandwidth, good beam quality and high power spectral density [1]. In particular, the high average power over large bandwidths makes SC light sources excellent candidates for ultra-high resolution optical coherence tomography (UHR-OCT) [2-5]. However, conventional SC sources suffer from high pulse-to-pulse intensity fluctuations as a result of the noise-sensitive nonlinear effects involved in the SC generation process [6-9]. This intensity noise from the SC source can limit the performance of OCT, resulting in a reduced signal-to-noise ratio (SNR) [10-12]. Much work has been done to reduce the noise of the SC sources for instance with fiber tapers [7,8] or increasing the repetition rate of the pump laser for averaging in the spectrometer [10,12]. An alternative approach is to use all-normal dispersion (ANDi) fibers [13,14] to generate SC light from well-known coherent nonlinear processes [15-17]. In fact, reduction of SC noise using ANDi fibers compared to anomalous dispersion SC pumped by sub-picosecond pulses has been recently demonstrated [18], but a cladding mode was used to stabilize the ANDi SC. In this work, we characterize the noise performance of a femtosecond pumped ANDi based SC and a commercial SC source in an UHR-OCT system at 1300 nm. We show that the ANDi based SC presents exceptional noise properties compared to a commercial source. An improvement of 5 dB in SNR is measured in the UHR-OCT system, and the noise behavior resembles that of a superluminiscent diode. This preliminary study is a step forward towards development of an ultra-low noise SC source at 1300 nm for ultra-high resolution OCT.

Solid electrolyte: The key for high-voltage lithium batteries

DOE PAGES

Li, Juchuan; Ma, Cheng; Chi, Miaofang; ...

2014-10-14

A solid-state high-voltage (5 V) lithium battery is demonstrated to deliver a cycle life of 10 000 with 90% capacity retention. Furthermore, the solid electrolyte enables the use of high-voltage cathodes and Li anodes with minimum side reactions, leading to a high Coulombic efficiency of 99.98+%.

High-Voltage, Low-Power BNC Feedthrough Terminator

NASA Technical Reports Server (NTRS)

Bearden, Douglas

2012-01-01

This innovation is a high-voltage, lowpower BNC (Bayonet Neill-Concelman) feedthrough that enables the user to terminate an instrumentation cable properly while connected to a high voltage, without the use of a voltage divider. This feedthrough is low power, which will not load the source, and will properly terminate the instrumentation cable to the instrumentation, even if the cable impedance is not constant. The Space Shuttle Program had a requirement to measure voltage transients on the orbiter bus through the Ground Lightning Measurement System (GLMS). This measurement has a bandwidth requirement of 1 MHz. The GLMS voltage measurement is connected to the orbiter through a DC panel. The DC panel is connected to the bus through a nonuniform cable that is approximately 75 ft (approximately equal to 23 m) long. A 15-ft (approximately equal to 5-m), 50-ohm triaxial cable is connected between the DC panel and the digitizer. Based on calculations and simulations, cable resonances and reflections due to mismatched impedances of the cable connecting the orbiter bus and the digitizer causes the output not to reflect accurately what is on the bus. A voltage divider at the DC panel, and terminating the 50-ohm cable properly, would eliminate this issue. Due to implementation issues, an alternative design was needed to terminate the cable properly without the use of a voltage divider. Analysis shows how the cable resonances and reflections due to the mismatched impedances of the cable connecting the orbiter bus and the digitizer causes the output not to reflect accurately what is on the bus. After simulating a dampening circuit located at the digitizer, simulations were performed to show how the cable resonances were dampened and the accuracy was improved significantly. Test cables built to verify simulations were accurate. Since the dampening circuit is low power, it can be packaged in a BNC feedthrough.

SABRE modification to a higher voltage high impedance inductive voltage adder (IVA)

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

Mazarakis, M.G.; Smith, D.L.; Poukey, J.W.

The SABRE accelerator was originally designed to operate as low impedance voltage adder with 40-ohm maximum output impedance in negative polarity operation and approximately 20 ohm in positive polarity. Because of the low impedance and higher than expected energy losses in the pulse forming network, the operating input cavity voltage is of the order of 800 kV which limits the total output voltage to {approximately} 8 MV for negative polarity and 5 to 6 MV for positive polarity. The modifications presented here aim to increase the output voltage in both polarities. A new high impedance central electrode was designed capablemore » of operating both in negative and positive polarities, and the number of pulse forming lines feeding the inductively isolated cavities was reduced to half. These modifications were recently tested in positive polarity. An increase in the total accelerating voltage from 5.5 MV to 9 MV was observed while stressing all components to the level required to achieve 12 MV in negative polarity. In these experiments only 65% of the usual operating intermediate store capacitor voltage was necessary (1.7 MV instead of 2.6 MV). Currently, the device is reconfigured for negative polarity tests. The cavities are rotated by 180{degree} and a 17-inch spool is added at the base of the cantilevered center electrode (cathode electrode). Positive and negative polarity results are presented and compared with simulations.« less

High-Capacity Cathode Material with High Voltage for Li-Ion Batteries

DOE PAGES

Shi, Ji -Lei; Xiao, Dong -Dong; Ge, Mingyuan; ...

2018-01-15

Electrochemical energy storage devices with a high energy density are an important technology in modern society, especially for electric vehicles. The most effective approach to improve the energy density of batteries is to search for high-capacity electrode materials. According to the concept of energy quality, a high-voltage battery delivers a highly useful energy, thus providing a new insight to improve energy density. Based on this concept, a novel and successful strategy to increase the energy density and energy quality by increasing the discharge voltage of cathode materials and preserving high capacity is proposed. The proposal is realized in high-capacity Li-richmore » cathode materials. The average discharge voltage is increased from 3.5 to 3.8 V by increasing the nickel content and applying a simple after-treatment, and the specific energy is improved from 912 to 1033 Wh kg-1. The current work provides an insightful universal principle for developing, designing, and screening electrode materials for high energy density and energy quality.« less

High-Capacity Cathode Material with High Voltage for Li-Ion Batteries

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

Shi, Ji -Lei; Xiao, Dong -Dong; Ge, Mingyuan

Electrochemical energy storage devices with a high energy density are an important technology in modern society, especially for electric vehicles. The most effective approach to improve the energy density of batteries is to search for high-capacity electrode materials. According to the concept of energy quality, a high-voltage battery delivers a highly useful energy, thus providing a new insight to improve energy density. Based on this concept, a novel and successful strategy to increase the energy density and energy quality by increasing the discharge voltage of cathode materials and preserving high capacity is proposed. The proposal is realized in high-capacity Li-richmore » cathode materials. The average discharge voltage is increased from 3.5 to 3.8 V by increasing the nickel content and applying a simple after-treatment, and the specific energy is improved from 912 to 1033 Wh kg-1. The current work provides an insightful universal principle for developing, designing, and screening electrode materials for high energy density and energy quality.« less

Mid-infrared ultra-high-Q resonators based on fluoride crystalline materials

NASA Astrophysics Data System (ADS)

Lecaplain, C.; Javerzac-Galy, C.; Gorodetsky, M. L.; Kippenberg, T. J.

2016-11-01

The unavailability of highly transparent materials in the mid-infrared has been the main limitation in the development of ultra-sensitive molecular sensors or cavity-based spectroscopy applications. Whispering gallery mode microresonators have attained ultra-high-quality (Q) factor resonances in the near-infrared and visible. Here we report ultra-high Q factors in the mid-infrared using polished alkaline earth metal fluoride crystals. Using an uncoated chalcogenide tapered fibre as a high-ideality coupler in the mid-infrared, we study via cavity ringdown technique the losses of BaF2, CaF2, MgF2 and SrF2 microresonators. We show that MgF2 is limited by multiphonon absorption by studying the temperature dependence of the Q factor. In contrast, in SrF2 and BaF2 the lower multiphonon absorption leads to ultra-high Q factors at 4.5 μm. These values correspond to an optical finesse of , the highest value achieved for any type of mid-infrared resonator to date.

Mid-infrared ultra-high-Q resonators based on fluoride crystalline materials

PubMed Central

Lecaplain, C.; Javerzac-Galy, C.; Gorodetsky, M. L.; Kippenberg, T. J.

2016-01-01

The unavailability of highly transparent materials in the mid-infrared has been the main limitation in the development of ultra-sensitive molecular sensors or cavity-based spectroscopy applications. Whispering gallery mode microresonators have attained ultra-high-quality (Q) factor resonances in the near-infrared and visible. Here we report ultra-high Q factors in the mid-infrared using polished alkaline earth metal fluoride crystals. Using an uncoated chalcogenide tapered fibre as a high-ideality coupler in the mid-infrared, we study via cavity ringdown technique the losses of BaF2, CaF2, MgF2 and SrF2 microresonators. We show that MgF2 is limited by multiphonon absorption by studying the temperature dependence of the Q factor. In contrast, in SrF2 and BaF2 the lower multiphonon absorption leads to ultra-high Q factors at 4.5 μm. These values correspond to an optical finesse of , the highest value achieved for any type of mid-infrared resonator to date. PMID:27869119

Mid-infrared ultra-high-Q resonators based on fluoride crystalline materials.

PubMed

Lecaplain, C; Javerzac-Galy, C; Gorodetsky, M L; Kippenberg, T J

2016-11-21

The unavailability of highly transparent materials in the mid-infrared has been the main limitation in the development of ultra-sensitive molecular sensors or cavity-based spectroscopy applications. Whispering gallery mode microresonators have attained ultra-high-quality (Q) factor resonances in the near-infrared and visible. Here we report ultra-high Q factors in the mid-infrared using polished alkaline earth metal fluoride crystals. Using an uncoated chalcogenide tapered fibre as a high-ideality coupler in the mid-infrared, we study via cavity ringdown technique the losses of BaF 2 , CaF 2 , MgF 2 and SrF 2 microresonators. We show that MgF 2 is limited by multiphonon absorption by studying the temperature dependence of the Q factor. In contrast, in SrF 2 and BaF 2 the lower multiphonon absorption leads to ultra-high Q factors at 4.5 μm. These values correspond to an optical finesse of , the highest value achieved for any type of mid-infrared resonator to date.

High voltage system: Plasma interaction summary

NASA Technical Reports Server (NTRS)

Stevens, N. John

1986-01-01

The possible interactions that could exist between a high voltage system and the space plasma environment are reviewed. A solar array is used as an example of such a system. The emphasis in this review is on the discrepancies that exist in this technology in both flight and ground experiment data. It has been found that, in ground testing, there are facility effects, cell size effects and area scaling uncertainties. For space applications there are area scaling and discharge concerns for an array as well as the influence of the large space structures on the collection process. There are still considerable uncertainties in the high voltage-space plasma interaction technology even after several years of effort.

Current Modulation of a Heterojunction Structure by an Ultra-Thin Graphene Base Electrode.

PubMed

Alvarado Chavarin, Carlos; Strobel, Carsten; Kitzmann, Julia; Di Bartolomeo, Antonio; Lukosius, Mindaugas; Albert, Matthias; Bartha, Johann Wolfgang; Wenger, Christian

2018-02-27

Graphene has been proposed as the current controlling element of vertical transport in heterojunction transistors, as it could potentially achieve high operation frequencies due to its metallic character and 2D nature. Simulations of graphene acting as a thermionic barrier between the transport of two semiconductor layers have shown cut-off frequencies larger than 1 THz. Furthermore, the use of n-doped amorphous silicon, (n)-a-Si:H, as the semiconductor for this approach could enable flexible electronics with high cutoff frequencies. In this work, we fabricated a vertical structure on a rigid substrate where graphene is embedded between two differently doped (n)-a-Si:H layers deposited by very high frequency (140 MHz) plasma-enhanced chemical vapor deposition. The operation of this heterojunction structure is investigated by the two diode-like interfaces by means of temperature dependent current-voltage characterization, followed by the electrical characterization in a three-terminal configuration. We demonstrate that the vertical current between the (n)-a-Si:H layers is successfully controlled by the ultra-thin graphene base voltage. While current saturation is yet to be achieved, a transconductance of ~230 μ S was obtained, demonstrating a moderate modulation of the collector-emitter current by the ultra-thin graphene base voltage. These results show promising progress towards the application of graphene base heterojunction transistors.

Evaluation of high temperature dielectric films for high voltage power electronic applications

NASA Technical Reports Server (NTRS)

Suthar, J. L.; Laghari, J. R.

1992-01-01

Three high temperature films, polyimide, Teflon perfluoroalkoxy and poly-P-xylene, were evaluated for possible use in high voltage power electronic applications, such as in high energy density capacitors, cables and microelectronic circuits. The dielectric properties, including permittivity and dielectric loss, were obtained in the frequency range of 50 Hz to 100 kHz at temperatures up to 200 C. The dielectric strengths at 60 Hz were determined as a function of temperature to 250 C. Confocal laser microscopy was performed to diagnose for voids and microimperfections within the film structure. The results obtained indicate that all films evaluated are capable of maintaining their high voltage properties, with minimal degradation, at temperatures up to 200 C. However, above 200 C, they lose some of their electrical properties. These films may therefore become viable candidates for high voltage power electronic applications at high temperatures.

High voltage holding in the negative ion sources with cesium deposition

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

Belchenko, Yu.; Abdrashitov, G.; Ivanov, A.

High voltage holding of the large surface-plasma negative ion source with cesium deposition was studied. It was found that heating of ion-optical system electrodes to temperature >100 °C facilitates the source conditioning by high voltage pulses in vacuum and by beam shots. The procedure of electrode conditioning and the data on high-voltage holding in the negative ion source with small cesium seed are described. The mechanism of high voltage holding improvement by depletion of cesium coverage is discussed.

Planar multijunction high voltage solar cells

NASA Technical Reports Server (NTRS)

Evans, J. C., Jr.; Chai, A. T.; Goradia, C.

1980-01-01

Technical considerations, preliminary results, and fabrication details are discussed for a family of high-voltage planar multi-junction (PMJ) solar cells which combine the attractive features of planar cells with conventional or interdigitated back contacts and the vertical multijunction (VMJ) solar cell. The PMJ solar cell is internally divided into many voltage-generating regions, called unit cells, which are internally connected in series. The key to obtaining reasonable performance from this device was the separation of top surface field regions over each active unit cell. Using existing solar cell fabricating methods, output voltages in excess of 20 volts per linear centimeter are possible. Analysis of the new device is complex, and numerous geometries are being studied which should provide substantial benefits in both normal sunlight usage as well as with concentrators.

Voltage-Load Sensitivity Matrix Based Demand Response for Voltage Control in High Solar Penetration Distribution Feeders

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

Zhu, Xiangqi; Wang, Jiyu; Mulcahy, David

This paper presents a voltage-load sensitivity matrix (VLSM) based voltage control method to deploy demand response resources for controlling voltage in high solar penetration distribution feeders. The IEEE 123-bus system in OpenDSS is used for testing the performance of the preliminary VLSM-based voltage control approach. A load disaggregation process is applied to disaggregate the total load profile at the feeder head to each load nodes along the feeder so that loads are modeled at residential house level. Measured solar generation profiles are used in the simulation to model the impact of solar power on distribution feeder voltage profiles. Different casemore » studies involving various PV penetration levels and installation locations have been performed. Simulation results show that the VLSM algorithm performance meets the voltage control requirements and is an effective voltage control strategy.« less

High Input Voltage, Silicon Carbide Power Processing Unit Performance Demonstration

NASA Technical Reports Server (NTRS)

Bozak, Karin E.; Pinero, Luis R.; Scheidegger, Robert J.; Aulisio, Michael V.; Gonzalez, Marcelo C.; Birchenough, Arthur G.

2015-01-01

A silicon carbide brassboard power processing unit has been developed by the NASA Glenn Research Center in Cleveland, Ohio. The power processing unit operates from two sources - a nominal 300-Volt high voltage input bus and a nominal 28-Volt low voltage input bus. The design of the power processing unit includes four low voltage, low power supplies that provide power to the thruster auxiliary supplies, and two parallel 7.5 kilowatt power supplies that are capable of providing up to 15 kilowatts of total power at 300-Volts to 500-Volts to the thruster discharge supply. Additionally, the unit contains a housekeeping supply, high voltage input filter, low voltage input filter, and master control board, such that the complete brassboard unit is capable of operating a 12.5 kilowatt Hall Effect Thruster. The performance of unit was characterized under both ambient and thermal vacuum test conditions, and the results demonstrate the exceptional performance with full power efficiencies exceeding 97. With a space-qualified silicon carbide or similar high voltage, high efficiency power device, this design could evolve into a flight design for future missions that require high power electric propulsion systems.

Electro-optic high voltage sensor

DOEpatents

Davidson, James R.; Seifert, Gary D.

2002-01-01

A small sized electro-optic voltage sensor capable of accurate measurement of high levels of voltages without contact with a conductor or voltage source is provided. When placed in the presence of an electric field, the sensor receives an input beam of electromagnetic radiation into the sensor. A polarization beam displacer serves as a filter to separate the input beam into two beams with orthogonal linear polarizations. The beam displacer is oriented in such a way as to rotate the linearly polarized beams such that they enter a Pockels crystal having at a preferred angle of 45 degrees. The beam displacer is therefore capable of causing a linearly polarized beam to impinge a crystal at a desired angle independent of temperature. The Pockels electro-optic effect induces a differential phase shift on the major and minor axes of the input beam as it travels through the Pockels crystal, which causes the input beam to be elliptically polarized. A reflecting prism redirects the beam back through the crystal and the beam displacer. On the return path, the polarization beam displacer separates the elliptically polarized beam into two output beams of orthogonal linear polarization representing the major and minor axes. The system may include a detector for converting the output beams into electrical signals, and a signal processor for determining the voltage based on an analysis of the output beams. The output beams are amplitude modulated by the frequency of the electric field and the amplitude of the output beams is proportional to the magnitude of the electric field, which is related to the voltage being measured.

COTS Li-Ion Cells in High Voltage Batteries

NASA Technical Reports Server (NTRS)

Davies, Francis; Darcy, Eric; Jeevarajan, Judy; Cowles, Phil

2003-01-01

Testing at NASA JSC and COMDEV shows that Commercial Off the Shelf (COTS) Li Ion cells can not be used in high voltage batteries safely without considering the voltage stresses that may be put on the protective devices in them during failure modes.

Multiloop Rapid-Rise/Rapid Fall High-Voltage Power Supply

NASA Technical Reports Server (NTRS)

Bearden, Douglas

2007-01-01

A proposed multiloop power supply would generate a potential as high as 1.25 kV with rise and fall times <100 s. This power supply would, moreover, be programmable to generate output potentials from 20 to 1,250 V and would be capable of supplying a current of at least 300 A at 1,250 V. This power supply is intended to be a means of electronic shuttering of a microchannel plate that would be used to intensify the output of a charge-coupled-device imager to obtain exposure times as short as 1 ms. The basic design of this power supply could also be adapted to other applications in which high voltages and high slew rates are needed. At the time of reporting the information for this article, there was no commercially available power supply capable of satisfying the stated combination of voltage, rise-time, and fall-time requirements. The power supply would include a preregulator that would be used to program a voltage 1/30 of the desired output voltage. By means of a circuit that would include a pulse-width modulator (PWM), two voltage doublers, and a transformer having two primary and two secondary windings, the preregulator output voltage would be amplified by a factor of 30. A resistor would limit the current by controlling a drive voltage applied to field-effect transistors (FETs) during turn-on of the PWM. Two feedback loops would be used to regulate the high output voltage. A pulse transformer would be used to turn on four FETs to short-circuit output capacitors when the outputs of the PWM were disabled. Application of a 0-to-5-V square to a PWM shut-down pin would cause a 20-to-1,250-V square wave to appear at the output.

A Double-Pole High Voltage High Current Switch

DTIC Science & Technology

2005-12-01

NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS Approved for public release; distribution is unlimited A DOUBLE- POLE HIGH...December 2005 3. REPORT TYPE AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE: A Double- Pole High Voltage High Current Switch 6. AUTHOR(S...to divert heavy charged particles, e.g. Cu+. 15. NUMBER OF PAGES 68 14. SUBJECT TERMS Double- Pole , Pulse Forming Inductive Network, PFIN

Design Method For Ultra-High Resolution Linear CCD Imagers

NASA Astrophysics Data System (ADS)

Sheu, Larry S.; Truong, Thanh; Yuzuki, Larry; Elhatem, Abdul; Kadekodi, Narayan

1984-11-01

This paper presents the design method to achieve ultra-high resolution linear imagers. This method utilizes advanced design rules and novel staggered bilinear photo sensor arrays with quadrilinear shift registers. Design constraint in the detector arrays and shift registers are analyzed. Imager architecture to achieve ultra-high resolution is presented. The characteristics of MTF, aliasing, speed, transfer efficiency and fine photolithography requirements associated with this architecture are also discussed. A CCD imager with advanced 1.5 um minimum feature size was fabricated. It is intended as a test vehicle for the next generation small sampling pitch ultra-high resolution CCD imager. Standard double-poly, two-phase shift registers were fabricated at an 8 um pitch using the advanced design rules. A special process step that blocked the source-drain implant from the shift register area was invented. This guaranteed excellent performance of the shift registers regardless of the small poly overlaps. A charge transfer efficiency of better than 0.99995 and maximum transfer speed of 8 MHz were achieved. The imager showed excellent performance. The dark current was less than 0.2 mV/ms, saturation 250 mV, adjacent photoresponse non-uniformity ± 4% and responsivity 0.7 V/ μJ/cm2 for the 8 μm x 6 μm photosensor size. The MTF was 0.6 at 62.5 cycles/mm. These results confirm the feasibility of the next generation ultra-high resolution CCD imagers.

Recycling potential for low voltage and high voltage high rupturing capacity fuse links.

PubMed

Psomopoulos, Constantinos S; Barkas, Dimitrios A; Kaminaris, Stavros D; Ioannidis, George C; Karagiannopoulos, Panagiotis

2017-12-01

Low voltage and high voltage high-rupturing-capacity fuse links are used in LV and HV installations respectively, protecting mainly the LV and HV electricity distribution and transportation networks. The Waste Electrical and Electronic Equipment Directive (2002/96/EC) for "Waste of electrical and electronic equipment" is the main related legislation and as it concerns electrical and electronic equipment, it includes electric fuses. Although, the fuse links consist of recyclable materials, only small scale actions have been implemented for their recycling around Europe. This work presents the possibilities for material recovery from this specialized industrial waste for which there are only limited volume data. Furthermore, in order to present the huge possibilities and environmental benefits, it presents the potential for recycling of HRC fuses used by the Public Power Corporation of Greece, which is the major consumer for the country, but one of the smallest ones in Europe and globally, emphasizing in this way in the issue. According to the obtained results, fuse recycling could contribute to the effort for minimize the impacts on the environment through materials recovery and reduction of the wastes' volume disposed of in landfills. Copyright © 2017 Elsevier Ltd. All rights reserved.

Precision optical slit for high heat load or ultra high vacuum

DOEpatents

Andresen, Nord C.; DiGennaro, Richard S.; Swain, Thomas L.

1995-01-01

This invention relates generally to slits used in optics that must be precisely aligned and adjusted. The optical slits of the present invention are useful in x-ray optics, x-ray beam lines, optical systems in which the entrance slit is critical for high wavelength resolution. The invention is particularly useful in ultra high vacuum systems where lubricants are difficult to use and designs which avoid the movement of metal parts against one another are important, such as monochrometers for high wavelength resolution with ultra high vacuum systems. The invention further relates to optical systems in which temperature characteristics of the slit materials is important. The present invention yet additionally relates to precision slits wherein the opposing edges of the slit must be precisely moved relative to a center line between the edges with each edge retaining its parallel orientation with respect to the other edge and/or the center line.

Ultra-low-power conversion and management techniques for thermoelectric energy harvesting applications

NASA Astrophysics Data System (ADS)

Fleming, Jerry W.

2010-04-01

Thermoelectric energy harvesting has increasingly gained acceptance as a potential power source that can be used for numerous commercial and military applications. However, power electronic designers have struggled to incorporate energy harvesting methods into their designs due to the relatively small voltage levels available from many harvesting device technologies. In order to bridge this gap, an ultra-low input voltage power conversion method is needed to convert small amounts of scavenged energy into a usable form of electricity. Such a method would be an enabler for new and improved medical devices, sensor systems, and other portable electronic products. This paper addresses the technical challenges involved in ultra-low-voltage power conversion by providing a solution utilizing novel power conversion techniques and applied technologies. Our solution utilizes intelligent power management techniques to control unknown startup conditions. The load and supply management functionality is also controlled in a deterministic manner. The DC to DC converter input operating voltage is 20mV with a conversion efficiency of 90% or more. The output voltage is stored into a storage device such as an ultra-capacitor or lithium-ion battery for use during brown-out or unfavorable harvesting conditions. Applications requiring modular, low power, extended maintenance cycles, such as wireless instrumentation would significantly benefit from the novel power conversion and harvesting techniques outlined in this paper.

30 CFR 75.705-2 - Repairs to energized surface high-voltage lines.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Repairs to energized surface high-voltage lines... Repairs to energized surface high-voltage lines. An energized high-voltage surface line may be repaired... on power circuits with a phase-to-phase nominal voltage no greater than 15,000 volts; (3) Such...

Influence of high-power nonlinear consumers on electric energy losses in mining high-voltage power line

NASA Astrophysics Data System (ADS)

Averbukh, M. A.; Prasol, D. A.

2018-03-01

The article elucidates the influence of high-power nonlinear consumers on electric energy losses in a mining high-voltage power line. The object of the study was a fragment of a power supply system of a mining enterprise with hoists. The investigation has assessed the electric energy losses conditioned by nonsinusoidal currents and voltages of the power line over a single hoist operation cycle. Also, the total electric energy losses in a high-voltage power line of a mining enterprise was calculated. The energy losses due to nonsinusoidal currents and voltages over single operation cycle of the cage hoist amount to 36.358 kWh. The presence of such losses increases total technological power and energy losses in the mining high-voltage power line by approximately 5-15%. The total energy losses in the components of the mining enterprise high-voltage power line caused by nonsinusoidal voltage are significant and lead to additional expenses of the company.

Neutron-induced single event burnout in high voltage electronics

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

Normand, E.; Wert, J.L.; Oberg, D.L.

Energetic neutrons with an atmospheric neutron spectrum, which were demonstrated to induce single event burnout in power MOSFETs, have been shown to induce burnout in high voltage (>3,000V) electronics when operated at voltages as low as 50% of rated voltage. The laboratory failure rates correlate well with field failure rates measured in Europe.

Surface voltage gradient role in high voltage solar array-plasma interaction: Center Director's discretionary fund

NASA Technical Reports Server (NTRS)

Carruth, M. R., Jr.

1985-01-01

A large amount of experimental and analytical effort has been directed toward understanding the plasma sheath growth and discharge phenomena which lead to high voltage solar array-space plasma interactions. An important question which has not been addressed is how the surface voltage gradient on such an array may affect these interactions. The results of this study indicate that under certain conditions, the voltage gradient should be taken into account when evaluating the effect on a solar array operating in a plasma environment.

Planar LTCC transformers for high voltage flyback converters.

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

Schofield, Daryl; Schare, Joshua M.; Glass, Sarah Jill

This paper discusses the design and use of low-temperature (850 C to 950 C) co-fired ceramic (LTCC) planar magnetic flyback transformers for applications that require conversion of a low voltage to high voltage (> 100V) with significant volumetric constraints. Measured performance and modeling results for multiple designs showed that the LTCC flyback transformer design and construction imposes serious limitations on the achievable coupling and significantly impacts the transformer performance and output voltage. This paper discusses the impact of various design factors that can provide improved performance by increasing transformer coupling and output voltage. The experiments performed on prototype units demonstratedmore » LTCC transformer designs capable of greater than 2 kV output. Finally, the work investigated the effect of the LTCC microstructure on transformer insulation. Although this paper focuses on generating voltages in the kV range, the experimental characterization and discussion presented in this work applies to designs requiring lower voltage.« less

Analysis of transistor and snubber turn-off dynamics in high-frequency high-voltage high-power converters

NASA Technical Reports Server (NTRS)

Wilson, P. M.; Wilson, T. G.; Owen, H. A., Jr.

1982-01-01

Dc to dc converters which operate reliably and efficiently at switching frequencies high enough to effect substantial reductions in the size and weight of converter energy storage elements are studied. A two winding current or voltage stepup (buck boost) dc-to-dc converter power stage submodule designed to operate in the 2.5-kW range, with an input voltage range of 110 to 180 V dc, and an output voltage of 250 V dc is emphasized. In order to assess the limitations of present day component and circuit technologies, a design goal switching frequency of 10 kHz was maintained. The converter design requirements represent a unique combination of high frequency, high voltage, and high power operation. The turn off dynamics of the primary circuit power switching transistor and its associated turn off snubber circuitry are investigated.

Analysis of transistor and snubber turn-off dynamics in high-frequency high-voltage high-power converters

NASA Astrophysics Data System (ADS)

Wilson, P. M.; Wilson, T. G.; Owen, H. A., Jr.

Dc to dc converters which operate reliably and efficiently at switching frequencies high enough to effect substantial reductions in the size and weight of converter energy storage elements are studied. A two winding current or voltage stepup (buck boost) dc-to-dc converter power stage submodule designed to operate in the 2.5-kW range, with an input voltage range of 110 to 180 V dc, and an output voltage of 250 V dc is emphasized. In order to assess the limitations of present day component and circuit technologies, a design goal switching frequency of 10 kHz was maintained. The converter design requirements represent a unique combination of high frequency, high voltage, and high power operation. The turn off dynamics of the primary circuit power switching transistor and its associated turn off snubber circuitry are investigated.

[Design of a high-voltage insulation testing system of X-ray high frequency generators].

PubMed

Huang, Yong; Mo, Guo-Ming; Wang, Yan; Wang, Hong-Zhi; Yu, Jie-Ying; Dai, Shu-Guang

2007-09-01

In this paper, we analyze the transformer of X-ray high-voltage high-frequency generators and, have designed and implemented a high-voltage insulation testing system for its oil tank using full-bridge series resonant soft switching PFM DC-DC converter.

High Input Voltage, Silicon Carbide Power Processing Unit Performance Demonstration

NASA Technical Reports Server (NTRS)

Bozak, Karin E.; Pinero, Luis R.; Scheidegger, Robert J.; Aulisio, Michael V.; Gonzalez, Marcelo C.; Birchenough, Arthur G.

2015-01-01

A silicon carbide brassboard power processing unit has been developed by the NASA Glenn Research Center in Cleveland, Ohio. The power processing unit operates from two sources: a nominal 300 Volt high voltage input bus and a nominal 28 Volt low voltage input bus. The design of the power processing unit includes four low voltage, low power auxiliary supplies, and two parallel 7.5 kilowatt (kW) discharge power supplies that are capable of providing up to 15 kilowatts of total power at 300 to 500 Volts (V) to the thruster. Additionally, the unit contains a housekeeping supply, high voltage input filter, low voltage input filter, and master control board, such that the complete brassboard unit is capable of operating a 12.5 kilowatt Hall effect thruster. The performance of the unit was characterized under both ambient and thermal vacuum test conditions, and the results demonstrate exceptional performance with full power efficiencies exceeding 97%. The unit was also tested with a 12.5kW Hall effect thruster to verify compatibility and output filter specifications. With space-qualified silicon carbide or similar high voltage, high efficiency power devices, this would provide a design solution to address the need for high power electric propulsion systems.

A low knee voltage and high breakdown voltage of 4H-SiC TSBS employing poly-Si/Ni Schottky scheme

NASA Astrophysics Data System (ADS)

Kim, Dong Young; Seok, Ogyun; Park, Himchan; Bahng, Wook; Kim, Hyoung Woo; Park, Ki Cheol

2018-02-01

We report a low knee voltage and high breakdown voltage 4H-SiC TSBS employing poly-Si/Ni dual Schottky contacts. A knee voltage was significantly improved from 0.75 to 0.48 V by utilizing an alternative low work-function material of poly-Si as an anode electrode. Also, reverse breakdown voltage was successfully improved from 901 to 1154 V due to a shrunk low-work-function Schottky region by a proposed self-align etching process between poly-Si and SiC. SiC TSBS with poly-Si/Ni dual Schottky scheme is a suitable structure for high-efficiency rectification and high-voltage blocking operation.

High-voltage supply for neutron tubes in well-logging applications

DOEpatents

Humphreys, D.R.

1982-09-15

A high voltage supply is provided for a neutron tube used in well logging. The biased pulse supply of the invention combines DC and full pulse techniques and produces a target voltage comprising a substantial negative DC bias component on which is superimposed a pulse whose negative peak provides the desired negative voltage level for the neutron tube. The target voltage is preferably generated using voltage doubling techniques and employing a voltage source which generates bipolar pulse pairs having an amplitude corresponding to the DC bias level.

High voltage supply for neutron tubes in well logging applications

DOEpatents

Humphreys, D. Russell

1989-01-01

A high voltage supply is provided for a neutron tube used in well logging. The "biased pulse" supply of the invention combines DC and "full pulse" techniques and produces a target voltage comprising a substantial negative DC bias component on which is superimposed a pulse whose negative peak provides the desired negative voltage level for the neutron tube. The target voltage is preferably generated using voltage doubling techniques and employing a voltage source which generates bipolar pulse pairs having an amplitude corresponding to the DC bias level.

High Voltage TAL Performance

NASA Technical Reports Server (NTRS)

Jacobson, David T.; Jankovsky, Robert S.; Rawlin, Vincent K.; Manzella, David H.

2001-01-01

The performance of a two-stage, anode layer Hall thruster was evaluated. Experiments were conducted in single and two-stage configurations. In single-stage configuration, the thruster was operated with discharge voltages ranging from 300 to 1700 V. Discharge specific impulses ranged from 1630 to 4140 sec. Thruster investigations were conducted with input power ranging from 1 to 8.7 kW, corresponding to power throttling of nearly 9: 1. An extensive two-stage performance map was generated. Data taken with total voltage (sum of discharge and accelerating voltage) constant revealed a decrease in thruster efficiency as the discharge voltage was increased. Anode specific impulse values were comparable in the single and two-stage configurations showing no strong advantage for two-stage operation.

DC High Voltage Conditioning of Photoemission Guns at Jefferson Lab FEL

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

Hernandez-Garcia, C.; Benson, S. V.; Biallas, G.

2009-08-04

DC high voltage photoemission electron guns with GaAs photocathodes have been used to produce polarized electron beams for nuclear physics experiments for about 3 decades with great success. In the late 1990s, Jefferson Lab adopted this gun technology for a free electron laser (FEL), but to assist with high bunch charge operation, considerably higher bias voltage is required compared to the photoguns used at the Jefferson Lab Continuous Electron Beam Accelerator Facility. The FEL gun has been conditioned above 400 kV several times, albeit encountering non-trivial challenges with ceramic insulators and field emission from electrodes. Recently, high voltage processing withmore » krypton gas was employed to process very stubborn field emitters. This work presents a summary of the high voltage techniques used to high voltage condition the Jefferson Lab FEL photoemission gun.« less

Precision optical slit for high heat load or ultra high vacuum

DOEpatents

Andresen, N.C.; DiGennaro, R.S.; Swain, T.L.

1995-01-24

This invention relates generally to slits used in optics that must be precisely aligned and adjusted. The optical slits of the present invention are useful in x-ray optics, x-ray beam lines, optical systems in which the entrance slit is critical for high wavelength resolution. The invention is particularly useful in ultra high vacuum systems where lubricants are difficult to use and designs which avoid the movement of metal parts against one another are important, such as monochromators for high wavelength resolution with ultra high vacuum systems. The invention further relates to optical systems in which temperature characteristics of the slit materials is important. The present invention yet additionally relates to precision slits wherein the opposing edges of the slit must be precisely moved relative to a center line between the edges with each edge retaining its parallel orientation with respect to the other edge and/or the center line. 21 figures.

High voltage pulse conditioning

DOEpatents

Springfield, Ray M.; Wheat, Jr., Robert M.

1990-01-01

Apparatus for conditioning high voltage pulses from particle accelerators in order to shorten the rise times of the pulses. Flashover switches in the cathode stalk of the transmission line hold off conduction for a determinable period of time, reflecting the early portion of the pulses. Diodes upstream of the switches divert energy into the magnetic and electrostatic storage of the capacitance and inductance inherent to the transmission line until the switches close.

Hybrid-PIC Modeling of a High-Voltage, High-Specific-Impulse Hall Thruster

NASA Technical Reports Server (NTRS)

Smith, Brandon D.; Boyd, Iain D.; Kamhawi, Hani; Huang, Wensheng

2013-01-01

The primary life-limiting mechanism of Hall thrusters is the sputter erosion of the discharge channel walls by high-energy propellant ions. Because of the difficulty involved in characterizing this erosion experimentally, many past efforts have focused on numerical modeling to predict erosion rates and thruster lifespan, but those analyses were limited to Hall thrusters operating in the 200-400V discharge voltage range. Thrusters operating at higher discharge voltages (V(sub d) >= 500 V) present an erosion environment that may differ greatly from that of the lower-voltage thrusters modeled in the past. In this work, HPHall, a well-established hybrid-PIC code, is used to simulate NASA's High-Voltage Hall Accelerator (HiVHAc) at discharge voltages of 300, 400, and 500V as a first step towards modeling the discharge channel erosion. It is found that the model accurately predicts the thruster performance at all operating conditions to within 6%. The model predicts a normalized plasma potential profile that is consistent between all three operating points, with the acceleration zone appearing in the same approximate location. The expected trend of increasing electron temperature with increasing discharge voltage is observed. An analysis of the discharge current oscillations shows that the model predicts oscillations that are much greater in amplitude than those measured experimentally at all operating points, suggesting that the differences in oscillation amplitude are not strongly associated with discharge voltage.

Ultra-high strain in epitaxial silicon carbide nanostructures utilizing residual stress amplification

NASA Astrophysics Data System (ADS)

Phan, Hoang-Phuong; Nguyen, Tuan-Khoa; Dinh, Toan; Ina, Ginnosuke; Kermany, Atieh Ranjbar; Qamar, Afzaal; Han, Jisheng; Namazu, Takahiro; Maeda, Ryutaro; Dao, Dzung Viet; Nguyen, Nam-Trung

2017-04-01

Strain engineering has attracted great attention, particularly for epitaxial films grown on a different substrate. Residual strains of SiC have been widely employed to form ultra-high frequency and high Q factor resonators. However, to date, the highest residual strain of SiC was reported to be limited to approximately 0.6%. Large strains induced into SiC could lead to several interesting physical phenomena, as well as significant improvement of resonant frequencies. We report an unprecedented nanostrain-amplifier structure with an ultra-high residual strain up to 8% utilizing the natural residual stress between epitaxial 3C-SiC and Si. In addition, the applied strain can be tuned by changing the dimensions of the amplifier structure. The possibility of introducing such a controllable and ultra-high strain will open the door to investigating the physics of SiC in large strain regimes and the development of ultra sensitive mechanical sensors.

Compact high voltage, high peak power, high frequency transformer for converter type modulator applications.

PubMed

Reghu, T; Mandloi, V; Shrivastava, Purushottam

2016-04-01

The design and development of a compact high voltage, high peak power, high frequency transformer for a converter type modulator of klystron amplifiers is presented. The transformer has been designed to operate at a frequency of 20 kHz and at a flux swing of ±0.6 T. Iron (Fe) based nanocrystalline material has been selected as a core for the construction of the transformer. The transformer employs a specially designed solid Teflon bobbin having 120 kV insulation for winding the high voltage secondary windings. The flux swing of the core has been experimentally found by plotting the hysteresis loop at actual operating conditions. Based on the design, a prototype transformer has been built which is per se a unique combination of high voltage, high frequency, and peak power specifications. The transformer was able to provide 58 kV (pk-pk) at the secondary with a peak power handling capability of 700 kVA. The transformation ratio was 1:17. The performance of the transformer is also presented and discussed.

High-power all-fiber ultra-low noise laser

NASA Astrophysics Data System (ADS)

Zhao, Jian; Guiraud, Germain; Pierre, Christophe; Floissat, Florian; Casanova, Alexis; Hreibi, Ali; Chaibi, Walid; Traynor, Nicholas; Boullet, Johan; Santarelli, Giorgio

2018-06-01

High-power ultra-low noise single-mode single-frequency lasers are in great demand for interferometric metrology. Robust, compact all-fiber lasers represent one of the most promising technologies to replace the current laser sources in use based on injection-locked ring resonators or multi-stage solid-state amplifiers. Here, a linearly polarized high-power ultra-low noise all-fiber laser is demonstrated at a power level of 100 W. Special care has been taken in the study of relative intensity noise (RIN) and its reduction. Using an optimized servo actuator to directly control the driving current of the pump laser diode, we obtain a large feedback bandwidth of up to 1.3 MHz. The RIN reaches - 160 dBc/Hz between 3 and 20 kHz.

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).

Copper wire theft and high voltage electrical burns.

PubMed

Francis, Eamon C; Shelley, Odhran P

2014-01-01

High voltage electrical burns are uncommon. However in the midst of our economic recession we are noticing an increasing number of these injuries. Copper wire is a valuable commodity with physical properties as an excellent conductor of electricity making it both ubiquitous in society and prized on the black market. We present two consecutive cases referred to the National Burns Unit who sustained life threatening injuries from the alleged theft of high voltage copper wire and its omnipresence on an international scale.

MOSFET-based high voltage short pulse generator for ultrasonic transducer excitation

NASA Astrophysics Data System (ADS)

Hidayat, Darmawan; Setianto, Syafei, Nendi Suhendi; Wibawa, Bambang Mukti

2018-02-01

This paper presents the generation of a high-voltage short pulse for the excitation of high frequency ultrasonic transducers. This is highly required in the purpose of various ultrasonic-based evaluations, particularly when high resolution measurement is necessary. A high voltage (+760 V) DC voltage source was pulsated by an ultrafast switching MOSFET which was driven by a pulse generator circuit consisting of an astable multivibrator, a one-shot multivibrator with Schmitt trigger input and a high current MOSFET driver. The generated pulses excited a 200-kHz and a 1-MHz ultrasonic transducers and tested in the transmission mode propagation to evaluate the performances of the generated pulse. The test results showed the generator were able to produce negative spike pulses up to -760 V voltage with the shortest time-width of 107.1 nanosecond. The transmission-received ultrasonic waves show frequency oscillation at 200 and 961 kHz and their amplitudes varied with the voltage of excitation pulse. These results conclude that the developed pulse generator is applicable to excite transducer for the generation of high frequency ultrasonic waves.

Disrupted latent inhibition in individuals at ultra high-risk for developing psychosis.

PubMed

Kraus, Michael; Rapisarda, Attilio; Lam, Max; Thong, Jamie Y J; Lee, Jimmy; Subramaniam, Mythily; Collinson, Simon L; Chong, Siow Ann; Keefe, Richard S E

2016-12-01

The addition of off-the-shelf cognitive measures to established prodromal criteria has resulted in limited improvement in the prediction of conversion to psychosis. Tests that assess cognitive processes central to schizophrenia might better identify those at highest risk. The latent inhibition paradigm assesses a subject's tendency to ignore irrelevant stimuli, a process integral to healthy perceptual and cognitive function that has been hypothesized to be a key deficit underlying the development of schizophrenia. In this study, 142 young people at ultra high-risk for developing psychosis and 105 controls were tested on a within-subject latent inhibition paradigm. Additionally, we later inquired about the strategy that each subject employed to complete the test, and further investigated the relationship between reported strategy and the extent of latent inhibition exhibited. Unlike controls, ultra high-risk subjects did not demonstrate a significant latent inhibition effect. This difference between groups became greater when controlling for strategy. The lack of latent inhibition effect in our ultra high-risk sample suggests that individuals at ultra high-risk for psychosis are impaired in their allocation of attentional resources based on past predictive value of repeated stimuli. This fundamental deficit in the allocation of attention may contribute to the broader array of cognitive impairments and clinical symptoms displayed by individuals at ultra high-risk for psychosis.

Proposal and Development of a High Voltage Variable Frequency Alternating Current Power System for Hybrid Electric Aircraft

NASA Technical Reports Server (NTRS)

Sadey, David J.; Taylor, Linda M.; Beach, Raymond F.

2016-01-01

The development of ultra-efficient commercial vehicles and the transition to low-carbon emission propulsion are seen as thrust paths within NASA Aeronautics. A critical enabler to these paths comes in the form of hybrid-electric propulsion systems. For megawatt-class systems, the best power system topology for these hybrid-electric propulsion systems is debatable. Current proposals within NASA and the Aero community suggest using a combination of AC and DC for power transmission. This paper proposes an alternative to the current thought model through the use of a primarily high voltage AC power generation, transmission, and distribution systems, supported by the Convergent Aeronautics Solutions (CAS) Project. This system relies heavily on the use of dual-fed induction machines, which provide high power densities, minimal power conversion, and variable speed operation. The paper presents background on the project along with the system architecture, development status and preliminary results.

Reliability and Characterization of High Voltage Power Capacitors

DTIC Science & Technology

2014-03-01

Cable The HVPS cable is a specialized coaxial cable that utilizes a high voltage bayonet connector. The cable itself has a voltage rating in excess...the( LabVIEW(program( GPIB( CABLE ( HVPS( HVPS( COAXIAL ( CABLE ( BNC( COAXIAL ( CABLE ( BNC( COAXIAL ( CABLE ( CAPACITOR(‘C’(DATA( CAPACITOR(‘A’(DATA( Circuit...16   F.   CABLES AND CONNECTORS ...................................................................16

Radio-frequency powered glow discharge device and method with high voltage interface

DOEpatents

Duckworth, Douglas C.; Marcus, R. Kenneth; Donohue, David L.; Lewis, Trousdale A.

1994-01-01

A high voltage accelerating potential, which is supplied by a high voltage direct current power supply, is applied to the electrically conducting interior wall of an RF powered glow discharge cell. The RF power supply desirably is electrically grounded, and the conductor carrying the RF power to the sample held by the probe is desirably shielded completely excepting only the conductor's terminal point of contact with the sample. The high voltage DC accelerating potential is not supplied to the sample. A high voltage capacitance is electrically connected in series between the sample on the one hand and the RF power supply and an impedance matching network on the other hand. The high voltage capacitance isolates the high DC voltage from the RF electronics, while the RF potential is passed across the high voltage capacitance to the plasma. An inductor protects at least the RF power supply, and desirably the impedance matching network as well, from a short that might occur across the high voltage capacitance. The discharge cell and the probe which holds the sample are configured and disposed to prevent the probe's components, which are maintained at ground potential, from bridging between the relatively low vacuum region in communication with the glow discharge maintained within the cell on the one hand, and the relatively high vacuum region surrounding the probe and cell on the other hand. The probe and cell also are configured and disposed to prevent the probe's components from electrically shorting the cell's components.

High-voltage pixel sensors for ATLAS upgrade

NASA Astrophysics Data System (ADS)

Perić, I.; Kreidl, C.; Fischer, P.; Bompard, F.; Breugnon, P.; Clemens, J.-C.; Fougeron, D.; Liu, J.; Pangaud, P.; Rozanov, A.; Barbero, M.; Feigl, S.; Capeans, M.; Ferrere, D.; Pernegger, H.; Ristic, B.; Muenstermann, D.; Gonzalez Sevilla, S.; La Rosa, A.; Miucci, A.; Nessi, M.; Iacobucci, G.; Backhaus, M.; Hügging, Fabian; Krüger, H.; Hemperek, T.; Obermann, T.; Wermes, N.; Garcia-Sciveres, M.; Quadt, A.; Weingarten, J.; George, M.; Grosse-Knetter, J.; Rieger, J.; Bates, R.; Blue, A.; Buttar, C.; Hynds, D.

2014-11-01

The high-voltage (HV-) CMOS pixel sensors offer several good properties: a fast charge collection by drift, the possibility to implement relatively complex CMOS in-pixel electronics and the compatibility with commercial processes. The sensor element is a deep n-well diode in a p-type substrate. The n-well contains CMOS pixel electronics. The main charge collection mechanism is drift in a shallow, high field region, which leads to a fast charge collection and a high radiation tolerance. We are currently evaluating the use of the high-voltage detectors implemented in 180 nm HV-CMOS technology for the high-luminosity ATLAS upgrade. Our approach is replacing the existing pixel and strip sensors with the CMOS sensors while keeping the presently used readout ASICs. By intelligence we mean the ability of the sensor to recognize a particle hit and generate the address information. In this way we could benefit from the advantages of the HV sensor technology such as lower cost, lower mass, lower operating voltage, smaller pitch, smaller clusters at high incidence angles. Additionally we expect to achieve a radiation hardness necessary for ATLAS upgrade. In order to test the concept, we have designed two HV-CMOS prototypes that can be readout in two ways: using pixel and strip readout chips. In the case of the pixel readout, the connection between HV-CMOS sensor and the readout ASIC can be established capacitively.

Solid-Body Fuse Developed for High- Voltage Space Power Missions

NASA Technical Reports Server (NTRS)

Dolce, James L.; Baez, Anastacio N.

2001-01-01

AEM Incorporated has completed the development, under a NASA Glenn Research Center contract, of a solid-body fuse for high-voltage power systems of satellites and spacecraft systems. High-reliability fuses presently defined by MIL-PRF-23419 do not meet the increased voltage and amperage requirements for the next generation of spacecraft. Solid-body fuses exhibit electrical and mechanical attributes that enable these fuses to perform reliably in the vacuum and high-vibration and -shock environments typically present in spacecraft applications. The construction and screening techniques for solid-body fuses described by MIL-PRF-23419/12 offer an excellent roadmap for the development of high-voltage solid-body fuses.

Search for ultra high energy astrophysical neutrinos with the ANITA experiment

NASA Astrophysics Data System (ADS)

Romero-Wolf, Andrew

2010-12-01

This work describes a search for cosmogenic neutrinos at energies above 1018 eV with the Antarctic Impulsive Transient Antenna (ANITA). ANITA is a balloon-borne radio interferometer designed to measure radio impulsive emission from particle showers produced in the Antarctic ice-sheet by ultra-high energy neutrinos (UHEnu). Flying at 37 km altitude the ANITA detector is sensitive to 1M km3 of ice and is expected to produce the highest exposure to ultra high energy neutrinos to date. The design, flight performance, and analysis of the first flight of ANITA in 2006 are the subject of this dissertation. Due to sparse anthropogenic backgrounds throughout the Antarctic continent, the ANITA analysis depends on high resolution directional reconstruction. An interferometric method was developed that not only provides high resolution but is also sensitive to very weak radio emissions. The results of ANITA provide the strongest constraints on current ultra-high energy neutrino models. In addition there was a serendipitous observation of ultra-high energy cosmic ray geosynchrotron emissions that are of distinct character from the expected neutrino signal. This thesis includes a study of the radio Cherenkov emission from ultra-high energy electromagnetic showers in ice in the time-domain. All previous simulations computed the radio pulse frequency spectrum. I developed a purely time-domain algorithm for computing radiation using the vector potentials of charged particle tracks. The results are fully consistent with previous frequency domain calculations and shed new light into the properties of the radio pulse in the time domain. The shape of the pulse in the time domain is directly related to the depth development of the excess charge in the shower and its width to the observation angle with respect to the Cherenkov direction. This information can be of great practical importance for interpreting actual data.

High-voltage positive electrode materials for lithium-ion batteries

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

Li, Wangda; Song, Bohang; Manthiram, Arumugam

The ever-growing demand for advanced rechargeable lithium-ion batteries in portable electronics and electric vehicles has spurred intensive research efforts over the past decade. The key to sustaining the progress in Li-ion batteries lies in the quest for safe, low-cost positive electrode (cathode) materials with desirable energy and power capabilities. One approach to boost the energy and power densities of batteries is to increase the output voltage while maintaining a high capacity, fast charge–discharge rate, and long service life. Here, this review gives an account of the various emerging high-voltage positive electrode materials that have the potential to satisfy these requirementsmore » either in the short or long term, including nickel-rich layered oxides, lithium-rich layered oxides, high-voltage spinel oxides, and high-voltage polyanionic compounds. The key barriers and the corresponding strategies for the practical viability of these cathode materials are discussed along with the optimization of electrolytes and other cell components, with a particular emphasis on recent advances in the literature. Finally, a concise perspective with respect to plausible strategies for future developments in the field is also provided.« less

High-voltage positive electrode materials for lithium-ion batteries

DOE PAGES

Li, Wangda; Song, Bohang; Manthiram, Arumugam

2017-04-25

The ever-growing demand for advanced rechargeable lithium-ion batteries in portable electronics and electric vehicles has spurred intensive research efforts over the past decade. The key to sustaining the progress in Li-ion batteries lies in the quest for safe, low-cost positive electrode (cathode) materials with desirable energy and power capabilities. One approach to boost the energy and power densities of batteries is to increase the output voltage while maintaining a high capacity, fast charge–discharge rate, and long service life. Here, this review gives an account of the various emerging high-voltage positive electrode materials that have the potential to satisfy these requirementsmore » either in the short or long term, including nickel-rich layered oxides, lithium-rich layered oxides, high-voltage spinel oxides, and high-voltage polyanionic compounds. The key barriers and the corresponding strategies for the practical viability of these cathode materials are discussed along with the optimization of electrolytes and other cell components, with a particular emphasis on recent advances in the literature. Finally, a concise perspective with respect to plausible strategies for future developments in the field is also provided.« less

Multiple high voltage output DC-to-DC power converter

NASA Technical Reports Server (NTRS)

Cronin, Donald L. (Inventor); Farber, Bertrand F. (Inventor); Gehm, Hartmut K. (Inventor); Goldin, Daniel S. (Inventor)

1977-01-01

Disclosed is a multiple output DC-to-DC converter. The DC input power is filtered and passed through a chopper preregulator. The chopper output is then passed through a current source inverter controlled by a squarewave generator. The resultant AC is passed through the primary winding of a transformer, with high voltages induced in a plurality of secondary windings. The high voltage secondary outputs are each solid-state rectified for passage to individual output loads. Multiple feedback loops control the operation of the chopper preregulator, one being responsive to the current through the primary winding and another responsive to the DC voltage level at a selected output.

Copper wire theft and high voltage electrical burns

PubMed Central

Francis, Eamon C; Shelley, Odhran P

2014-01-01

High voltage electrical burns are uncommon. However in the midst of our economic recession we are noticing an increasing number of these injuries. Copper wire is a valuable commodity with physical properties as an excellent conductor of electricity making it both ubiquitous in society and prized on the black market. We present two consecutive cases referred to the National Burns Unit who sustained life threatening injuries from the alleged theft of high voltage copper wire and its omnipresence on an international scale. PMID:25356371

Imaging frontostriatal function in ultra-high-risk, early, and chronic schizophrenia during executive processing.

PubMed

Morey, Rajendra A; Inan, Seniha; Mitchell, Teresa V; Perkins, Diana O; Lieberman, Jeffrey A; Belger, Aysenil

2005-03-01

Individuals experiencing prodromal symptoms of schizophrenia (ultra-high-risk group) demonstrate impaired performance on tasks of executive function, attention, and working memory. The neurobiological underpinnings of such executive deficits in ultra-high-risk individuals remains unclear. We assessed frontal and striatal functions during a visual oddball continuous performance task, in ultra-high-risk, early, and chronic schizophrenic patients with the use of functional magnetic resonance imaging. Cross-sectional case-control design. Community; outpatient clinic. Patients Fifty-two individuals (control, n = 16; ultra-high risk, n = 10; early, n = 15; chronic, n = 11) from a referred clinical sample and age- and sex-matched control volunteers underwent scanning. Percentage of active voxels and percentage signal change calculated for the anterior cingulate gyrus (ACG), middle frontal gyrus (MFG), inferior frontal gyrus (IFG), basal ganglia, and thalamus. Performance on the visual oddball task was measured with percentage of hits and d' (a measure based on the hit rate and the false-alarm rate). The ultra-high-risk group showed significantly smaller differential activation between task-relevant and task-irrelevant stimuli in the frontal regions (ACG, IFG, MFG) than the control group. Frontostriatal activation associated with target stimuli in the early and chronic groups was significantly lower than the control group, while the ultra-high-risk group showed a trend toward the early group. Our findings suggest that prefrontal function begins to decline before the onset of syndromally defined illness and hence may represent a vulnerability marker in assessing the risk of developing psychotic disorders among ultra-high-risk individuals.

30 CFR 77.704 - Work on high-voltage lines; deenergizing and grounding.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Work on high-voltage lines; deenergizing and... OF UNDERGROUND COAL MINES Grounding § 77.704 Work on high-voltage lines; deenergizing and grounding. High-voltage lines shall be deenergized and grounded before work is performed on them, except that...

High voltage bushing having weathershed and surrounding stress relief collar

DOEpatents

Cookson, Alan H.

1981-01-01

A high voltage electric bushing comprises a hollow elongated dielectric weathershed which encloses a high voltage conductor. A collar formed of high voltage dielectric material is positioned over the weathershed and is bonded thereto by an interface material which precludes moisture-like contaminants from entering between the bonded portions. The collar is substantially thicker than the adjacent weathershed which it surrounds, providing relief of the electric stresses which would otherwise appear on the outer surface of the weathershed. The collar may include a conductive ring or capacitive foil to further relieve electric stresses experienced by the bushing.

High-Voltage, Asymmetric-Waveform Generator

NASA Technical Reports Server (NTRS)

Beegle, Luther W.; Duong, Tuan A.; Duong, Vu A.; Kanik, Isik

2008-01-01

The shapes of waveforms generated by commercially available analytical separation devices, such as some types of mass spectrometers and differential mobility spectrometers are, in general, inadequate and result in resolution degradation in output spectra. A waveform generator was designed that would be able to circumvent these shortcomings. It is capable of generating an asymmetric waveform, having a peak amplitude as large as 2 kV and frequency of several megahertz, which can be applied to a capacitive load. In the original intended application, the capacitive load would consist of the drift plates in a differential-mobility spectrometer. The main advantage to be gained by developing the proposed generator is that the shape of the waveform is made nearly optimum for various analytical devices requiring asymmetric-waveform such as differential-mobility spectrometers. In addition, this waveform generator could easily be adjusted to modify the waveform in accordance with changed operational requirements for differential-mobility spectrometers. The capacitive nature of the load is an important consideration in the design of the proposed waveform generator. For example, the design provision for shaping the output waveform is based partly on the principle that (1) the potential (V) on a capacitor is given by V=q/C, where C is the capacitance and q is the charge stored in the capacitor; and, hence (2) the rate of increase or decrease of the potential is similarly proportional to the charging or discharging current. The proposed waveform generator would comprise four functional blocks: a sine-wave generator, a buffer, a voltage shifter, and a high-voltage switch (see Figure 1). The sine-wave generator would include a pair of operational amplifiers in a feedback configuration, the parameters of which would be chosen to obtain a sinusoidal timing signal of the desired frequency. The buffer would introduce a slight delay (approximately equal to 20 ns) but would otherwise

Instability analysis of charges trapped in the oxide of metal-ultra thin oxide-semiconductor structures

NASA Astrophysics Data System (ADS)

Aziz, A.; Kassmi, K.; Maimouni, R.; Olivié, F.; Sarrabayrouse, G.; Martinez, A.

2005-09-01

In this paper, we present the theoretical and experimental results of the influence of a charge trapped in ultra-thin oxide of metal/ultra-thin oxide/semiconductor structures (MOS) on the I(Vg) current-voltage characteristics when the conduction is of the Fowler-Nordheim (FN) tunneling type. The charge, which is negative, is trapped near the cathode (metal/oxide interface) after constant current injection by the metal (Vg<0). Of particular interest is the influence on the Δ Vg(Vg) shift over the whole I(Vg) characteristic at high field (greater than the injection field (>12.5 MV/cm)). It is shown that the charge centroid varies linearly with respect to the voltage Vg. The behavior at low field (<12.5 MV/cm) is analyzed in référence A. Aziz, K. Kassmi, Ka. Kassmi, F. Olivié, Semicond. Sci. Technol. 19, 877 (2004) and considers that the trapped charge centroid is fixed. The results obtained make it possible to analyze the influence of the injected charge and the applied field on the centroid position of the trapped charge, and to highlight the charge instability in the ultra-thin oxide of MOS structures.

Study of a High Voltage Ion Engine Power Supply

NASA Technical Reports Server (NTRS)

Stuart, Thomas A.; King, Roger J.; Mayer, Eric

1996-01-01

A complete laboratory breadboard version of a ion engine power converter was built and tested. This prototype operated on a line voltage of 80-120 Vdc, and provided output ratings of 1100 V at 1.8 kW, and 250 V at 20 mA. The high-voltage (HV) output voltage rating was revised from the original value of 1350 V at the beginning of the project. The LV output was designed to hold up during a 1-A surge current lasting up to 1 second. The prototype power converter included a internal housekeeping power supply which also operated from the line input. The power consumed in housekeeping was included in the overall energy budget presented for the ion engine converter. HV and LV output voltage setpoints were commanded through potentiometers. The HV converter itself reached its highest power efficiency of slightly over 93% at low line and maximum output. This would dip below 90% at high line. The no-load (rated output voltages, zero load current) power consumption of the entire system was less than 13 W. A careful loss breakdown shows that converter losses are predominately Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET) conduction losses and HV rectifier snubbing losses, with the rectifier snubbing losses becoming predominant at high line. This suggests that further improvements in power efficiency could best be obtained by either developing a rectifier that was adequately protected against voltage overshoot with less snubbing, or by developing a pre-regulator to reduced the range of line voltage on the converter. The transient testing showed the converter to be fully protected against load faults, including a direct short-circuit from the HV output to the LV output terminals. Two currents sensors were used: one to directly detect any core ratcheting on the output transformer and re-initiate a soft start, and the other to directly detect a load fault and quickly shut down the converter for load protection. The finished converter has been extensively fault tested

High voltage and high specific capacity dual intercalating electrode Li-ion batteries

NASA Technical Reports Server (NTRS)

Blanco, Mario (Inventor); West, William C. (Inventor)

2010-01-01

The present invention provides high capacity and high voltage Li-ion batteries that have a carbonaceous cathode and a nonaqueous electrolyte solution comprising LiF salt and an anion receptor that binds the fluoride ion. The batteries can comprise dual intercalating electrode Li ion batteries. Methods of the present invention use a cathode and electrode pair, wherein each of the electrodes reversibly intercalate ions provided by a LiF salt to make a high voltage and high specific capacity dual intercalating electrode Li-ion battery. The present methods and systems provide high-capacity batteries particularly useful in powering devices where minimizing battery mass is important.

Control of Analyte Electrolysis in Electrospray Ionization Mass Spectrometry Using Repetitively Pulsed High Voltage

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

Kertesz, Vilmos; Van Berkel, Gary J

2011-01-01

Analyte electrolysis using a repetitively pulsed high voltage ion source was investigated and compared to that using a regular, continuously operating direct current high voltage ion source in electrospray ionization mass spectrometry. The extent of analyte electrolysis was explored as a function of the length and frequency of the high voltage pulse using the model compound reserpine in positive ion mode. Using +5 kV as the maximum high voltage amplitude, reserpine was oxidized to its 2, 4, 6 and 8-electron oxidation products when direct current high voltage was employed. In contrast, when using a pulsed high voltage, oxidation of reserpinemore » was eliminated by employing the appropriate high voltage pulse length and frequency. This effect was caused by inefficient mass transport of the analyte to the electrode surface during the duration of the high voltage pulse and the subsequent relaxation of the emitter electrode/ electrolyte interface during the time period when the high voltage was turned off. This mode of ESI source operation allows for analyte electrolysis to be quickly and simply switched on or off electronically via a change in voltage pulse variables.« less

A method for encapsulating high voltage power transformers

NASA Astrophysics Data System (ADS)

Sanchez, Robert O.

Voltage breakdowns become a major concern in reducing the size of high-voltage power converter transformers. Even the smallest of voids can provide a path for corona discharge which can cause a dielectric breakdown leading to a transformer failure. A method of encapsulating small high voltage transformers has been developed. The method virtually eliminates voids in the impregnation material, provides an exceptional dielectric between windings and provides a mechanically rugged package. The encapsulation material is a carboxyl terminated butadiene nitril (CTBN) modified mica filled epoxy. The method requires heat/vacuum to impregnate the coil and heat/pressure to cure the encapsulant. The transformer package utilizes a diallyl phthalate (DAP) contact assembly in which a coated core/coil assembly is mounted and soldered. This assembly is then loaded into an RTV mold and the encapsulation process begins.

Challenges and approaches for high-voltage spinel lithium-ion batteries.

PubMed

Kim, Jung-Hyun; Pieczonka, Nicholas P W; Yang, Li

2014-07-21

Lithium-ion (Li-ion) batteries have been developed for electric vehicle (EV) applications, owing to their high energy density. Recent research and development efforts have been devoted to finding the next generation of cathode materials for Li-ion batteries to extend the driving distance of EVs and lower their cost. LiNi(0.5)Mn(1.5)O(4) (LNMO) high-voltage spinel is a promising candidate for a next-generation cathode material based on its high operating voltage (4.75 V vs. Li), potentially low material cost, and excellent rate capability. Over the last decade, much research effort has focused on achieving a fundamental understanding of the structure-property relationship in LNMO materials. Recent studies, however, demonstrated that the most critical barrier for the commercialization of high-voltage spinel Li-ion batteries is electrolyte decomposition and concurrent degradative reactions at electrode/electrolyte interfaces, which results in poor cycle life for LNMO/graphite full cells. Despite scattered reports addressing these processes in high-voltage spinel full cells, they have not been consolidated into a systematic review article. With this perspective, emphasis is placed herein on describing the challenges and the various approaches to mitigate electrolyte decomposition and other degradative reactions in high-voltage spinel cathodes in full cells. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Radio-frequency powered glow discharge device and method with high voltage interface

DOEpatents

Duckworth, D.C.; Marcus, R.K.; Donohue, D.L.; Lewis, T.A.

1994-06-28

A high voltage accelerating potential, which is supplied by a high voltage direct current power supply, is applied to the electrically conducting interior wall of an RF powered glow discharge cell. The RF power supply desirably is electrically grounded, and the conductor carrying the RF power to the sample held by the probe is desirably shielded completely excepting only the conductor's terminal point of contact with the sample. The high voltage DC accelerating potential is not supplied to the sample. A high voltage capacitance is electrically connected in series between the sample on the one hand and the RF power supply and an impedance matching network on the other hand. The high voltage capacitance isolates the high DC voltage from the RF electronics, while the RF potential is passed across the high voltage capacitance to the plasma. An inductor protects at least the RF power supply, and desirably the impedance matching network as well, from a short that might occur across the high voltage capacitance. The discharge cell and the probe which holds the sample are configured and disposed to prevent the probe's components, which are maintained at ground potential, from bridging between the relatively low vacuum region in communication with the glow discharge maintained within the cell on the one hand, and the relatively high vacuum region surrounding the probe and cell on the other hand. The probe and cell also are configured and disposed to prevent the probe's components from electrically shorting the cell's components. 11 figures.

Fabrication of ultra thin anodic aluminium oxide membranes by low anodization voltages

NASA Astrophysics Data System (ADS)

Pastore, I.; Poplausks, R.; Apsite, I.; Pastare, I.; Lombardi, F.; Erts, D.

2011-06-01

Formation of ultrathin anodised aluminium oxide (AAO) membranes with high aspect ratio by Al anodization in sulphuric and oxalic acids at low potentials was investigated. Low anodization potentials ensure slow electrochemical reaction speeds and formation of AAO membranes with pore diameter and thickness below 20 nm and 70 nm respectively. Minimum time necessary for formation of continuous AAO membranes was determined. AAO membrane pore surface was covered with polymer Paraloid B72TM to transport it to the selected substrate. The fabricated ultra thin AAO membranes could be used to fabricate nanodot arrays on different surfaces.

Deep Space One High-Voltage Bus Management

NASA Technical Reports Server (NTRS)

Rachocki, Ken; Nieraeth, Donald

1999-01-01

The design of the High Voltage Power Converter Unit on DS1 allows both the spacecraft avionics and ion propulsion to operate in a stable manner near the PPP of the solar array. This approach relies on a fairly well-defined solar array model to determine the projected PPP. The solar array voltage set-points have to be updated every week to maintain operation near PPP. Stable operation even to the LEFT of the Peak Power Point is achievable so long as you do not change the operating power level of the ion engine. The next step for this technology is to investigate the use of onboard autonomy to determine the optimum SA voltage regulation set-point (i.e. near the PPP); this is for future missions that have one or more ion propulsion subsystems.

Special features of large-size resistors for high-voltage pulsed installations

NASA Astrophysics Data System (ADS)

Minakova, N. N.; Ushakov, V. Ya.

2017-12-01

Many structural materials in pulsed power engineering operate under extreme conditions. For example, in high-voltage electrophysical installations among which there are multistage high-voltage pulse generators (HVPG), rigid requirements are imposed on characteristics of solid-state resistors that are more promising in comparison with widely used liquid resistors. Materials of such resistors shall be able to withstand strong electric fields, operate at elevated temperatures, in transformer oil, etc. Effective charge of high-voltage capacitors distributed over the HVPG steps (levels) requires uniform voltage distribution along the steps of the installation that can be obtained using large-size resistors. For such applications, polymer composite materials are considered rather promising. They can work in transformer oil and have small mass in comparison with bulky resistors on inorganic basis. This allows technical solutions already developed and implemented in HVPG with liquid resistors to be employed. This paper is devoted to the solution of some tasks related to the application of filled polymers in high-voltage engineering.

Development of Ultra-Low Noise, High Sensitivity Planar Metal Grating Coupled AlGaAs/GaAs Multiquantum Well IR Detectors for Focal Plane Array Staring IR Sensor Systems

DTIC Science & Technology

1992-02-01

Development of Ultra-Low Noise , High Sensitivity Planar Metal Grating Coupled AlGaAs/GaAs Multiquantum Well IR Detectors for Focal Plane Array Staring IR...dark current at 77 K was 10 times lower than the conventional QWIP reported in the literature. anid the BTM QWIP showed a largely enhanced intersubband...bias voltage in the BTM and SBTM1 QWIPs . The results reveal thiat therinionic emission is dominant current conduction mechianismn at higher temp

Fast and sensitive analysis of beta blockers by ultra-high-performance liquid chromatography coupled with ultra-high-resolution TOF mass spectrometry.

PubMed

Tomková, Jana; Ondra, Peter; Kocianová, Eva; Václavík, Jan

2017-07-01

This paper presents a method for the determination of acebutolol, betaxolol, bisoprolol, metoprolol, nebivolol and sotalol in human serum by liquid-liquid extraction and ultra-high-performance liquid chromatography coupled with ultra-high-resolution TOF mass spectrometry. After liquid-liquid extraction, beta blockers were separated on a reverse-phase analytical column (Acclaim RS 120; 100 × 2.1 mm, 2.2 μm). The total run time was 6 min for each sample. Linearity, limit of detection, limit of quantification, matrix effects, specificity, precision, accuracy, recovery and sample stability were evaluated. The method was successfully applied to the therapeutic drug monitoring of 108 patients with hypertension. This method was also used for determination of beta blockers in 33 intoxicated patients. Copyright © 2016 John Wiley & Sons, Ltd.

An Inexpensive Source of High Voltage

NASA Astrophysics Data System (ADS)

Saraiva, Carlos

2012-04-01

As a physics teacher I like recycling old apparatus and using them for demonstrations in my classes.1-4 In physics laboratories in schools, sources of high voltage include induction coils or electronic systems that can be bought from companies that sell lab equipment. But these sources can be very expensive. In this article, I will explain how you can use a car ignition coil as a high voltage source. Such a coil can be obtained from an old car found in a car salvage yard and used to power cathode ray tubes and discharge tubes to observe the spectra. It can also be used as a source of ignition to simulate explosive combustion that occurs in car engines, rockets, etc. You can also buy these coils in shops that sell car accessories and they are cheaper than induction coils. In Fig. 1 you can see a coil that I used.

High voltage switch triggered by a laser-photocathode subsystem

DOEpatents

Chen, Ping; Lundquist, Martin L.; Yu, David U. L.

2013-01-08

A spark gap switch for controlling the output of a high voltage pulse from a high voltage source, for example, a capacitor bank or a pulse forming network, to an external load such as a high gradient electron gun, laser, pulsed power accelerator or wide band radar. The combination of a UV laser and a high vacuum quartz cell, in which a photocathode and an anode are installed, is utilized as triggering devices to switch the spark gap from a non-conducting state to a conducting state with low delay and low jitter.

BAKABLE ULTRA-HIGH VACUUM VALVE

DOEpatents

Mark, J.T.; Gantz, I.H.

1962-07-10

S>This patent relates to a valve useful in applications involving successively closing and opening a communication between a chamber evacuated to an ultra-high vacuum condition of the order of 10/sup -10/ millimeters of mercury and another chamber or the ambient. The valve is capable of withstanding extended baking at 450 deg C and repeated opening and closing without repiacement of the valve seat (approximately 200 cycle limit). The seal is formed by mutual interdiffusion weld, coerced by a pneumatic actuator. (AEC)

Spacewalking_in_Ultra_High_Definition

NASA Image and Video Library

2017-07-21

Ever wonder what the spacewalker sees while you’re looking at him or her? Here’s your answer, courtesy of NASA astronaut Jack Fischer. This Ultra High Definition clip shows Fischer outside the International Space Station during a spacewalk on Expedition 51 in May 2017, and the view from a small camera attached to his spacesuit at the same time. Music by Joakim Karud. _______________________________________ FOLLOW THE SPACE STATION! Twitter: https://twitter.com/Space_Station Facebook: https://www.facebook.com/ISS Instagram: https://instagram.com/iss/

New experimental perspectives for soft x-ray absorption spectroscopies at ultra-low temperatures below 50 mK and in high magnetic fields up to 7 T

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

Beeck, T., E-mail: torben.beeck@desy.de; Baev, I.; Gieschen, S.

2016-04-15

A new ultra-low temperature experiment including a superconducting vector magnet has been developed for soft x-ray absorption spectroscopy experiments at third generation synchrotron light sources. The sample is cooled below 50 mK by a cryogen free {sup 3}He-{sup 4}He dilution refrigerator. At the same time, magnetic fields of up to ±7 T in the horizontal direction and ±0.5 T in the vertical direction can be applied by a superconducting vector magnet. The setup allows to study ex situ and in situ prepared samples, offered by an attached UHV preparation chamber with load lock. The transfer of the prepared samples betweenmore » the preparation section and the dilution refrigerator is carried out under cryogenic temperatures. First commissioning studies have been carried out at the Variable Polarization XUV Beamline P04 at PETRA III and the influence of the incident photon beam to the sample temperature has been studied.« less

Technical Trend of Environment-friendly High Voltage Vacuum Circuit Breaker (VCB)

NASA Astrophysics Data System (ADS)

Okubo, Hitoshi

Vacuum Circuit Breakers (VCBs) have widely been used for low and medium voltage level, because of their high current interruption performance, maintenance free operations and environment-friendly characteristics. The VCB is now going to be applied to higher voltage systems for transmission and substation use. In this paper, the recent technical trend and future perspectives of high voltage VCBs are described, as well as their technical background.

Laser guiding of Tesla coil high voltage discharges.

PubMed

Henriksson, Markus; Daigle, Jean-Francois; Théberge, Francis; Châteauneuf, Marc; Dubois, Jacques

2012-06-04

We have investigated the guiding and triggering of discharges from a Tesla coil type 280 kHz AC high voltage source using filaments created by a femtosecond Terawatt laser pulse. Without the laser the discharges were maximum 30 cm long. With the laser straight, guided discharges up to 110 cm length were detected. The discharge length was limited by the voltage amplitude of the Tesla coil.

Highly hydrogen-sensitive thermal desorption spectroscopy system for quantitative analysis of low hydrogen concentration (˜1 × 1016 atoms/cm3) in thin-film samples

NASA Astrophysics Data System (ADS)

Hanna, Taku; Hiramatsu, Hidenori; Sakaguchi, Isao; Hosono, Hideo

2017-05-01

We developed a highly hydrogen-sensitive thermal desorption spectroscopy (HHS-TDS) system to detect and quantitatively analyze low hydrogen concentrations in thin films. The system was connected to an in situ sample-transfer chamber system, manipulators, and an rf magnetron sputtering thin-film deposition chamber under an ultra-high-vacuum (UHV) atmosphere of ˜10-8 Pa. The following key requirements were proposed in developing the HHS-TDS: (i) a low hydrogen residual partial pressure, (ii) a low hydrogen exhaust velocity, and (iii) minimization of hydrogen thermal desorption except from the bulk region of the thin films. To satisfy these requirements, appropriate materials and components were selected, and the system was constructed to extract the maximum performance from each component. Consequently, ˜2000 times higher sensitivity to hydrogen than that of a commercially available UHV-TDS system was achieved using H+-implanted Si samples. Quantitative analysis of an amorphous oxide semiconductor InGaZnO4 thin film (1 cm × 1 cm × 1 μm thickness, hydrogen concentration of 4.5 × 1017 atoms/cm3) was demonstrated using the HHS-TDS system. This concentration level cannot be detected using UHV-TDS or secondary ion mass spectroscopy (SIMS) systems. The hydrogen detection limit of the HHS-TDS system was estimated to be ˜1 × 1016 atoms/cm3, which implies ˜2 orders of magnitude higher sensitivity than that of SIMS and resonance nuclear reaction systems (˜1018 atoms/cm3).

Stable electrolyte for high voltage electrochemical double-layer capacitors

DOE PAGES

Ruther, Rose E.; Sun, Che -Nan; Holliday, Adam; ...

2016-12-28

A simple electrolyte consisting of NaPF 6 salt in 1,2-dimethoxyethane (DME) can extend the voltage window of electric double-layer capacitors (EDLCs) to >3.5 V. DME does not passivate carbon electrodes at very negative potentials (near Na/Na +), extending the practical voltage window by about 1.0 V compared to standard, non-aqueous electrolytes based on acetonitrile. The voltage window is demonstrated in two- and three-electrode cells using a combination of electrochemical impedance spectroscopy (EIS), charge-discharge cycling, and measurements of leakage current. DME-based electrolytes cannot match the high conductivity of acetonitrile solutions, but they can satisfy applications that demand high energy density atmore » moderate power. The conductivity of NaPF 6 in DME is comparable to commercial lithium-ion battery electrolytes and superior to most ionic liquids. Lastly, factors that limit the voltage window and EDLC energy density are discussed, and strategies to further boost energy density are proposed.« less

Lithium-Ion Electrolytes with Improved Safety Tolerance to High Voltage Systems

NASA Technical Reports Server (NTRS)

Smart, Marshall C. (Inventor); Prakash, Surya G. (Inventor); Bugga, Ratnakumar V. (Inventor); Krause, Frederick C. (Inventor)

2015-01-01

The invention discloses various embodiments of electrolytes for use in lithium-ion batteries, the electrolytes having improved safety and the ability to operate with high capacity anodes and high voltage cathodes. In one embodiment there is provided an electrolyte for use in a lithium-ion battery comprising an anode and a high voltage cathode. The electrolyte has a mixture of a cyclic carbonate of ethylene carbonate (EC) or mono-fluoroethylene carbonate (FEC) co-solvent, ethyl methyl carbonate (EMC), a flame retardant additive, a lithium salt, and an electrolyte additive that improves compatibility and performance of the lithium-ion battery with a high voltage cathode. The lithium-ion battery is charged to a voltage in a range of from about 2.0 V (Volts) to about 5.0 V (Volts).

HIGH VOLTAGE, HIGH CURRENT SPARK GAP SWITCH

DOEpatents

Dike, R.S.; Lier, D.W.; Schofield, A.E.; Tuck, J.L.

1962-04-17

A high voltage and current spark gap switch comprising two main electrodes insulatingly supported in opposed spaced relationship and a middle electrode supported medially between the main electrodes and symmetrically about the median line of the main electrodes is described. The middle electrode has a perforation aligned with the median line and an irradiation electrode insulatingly supported in the body of the middle electrode normal to the median line and protruding into the perforation. (AEC)

Completely explosive ultracompact high-voltage nanosecond pulse-generating system

NASA Astrophysics Data System (ADS)

Shkuratov, Sergey I.; Talantsev, Evgueni F.; Baird, Jason; Rose, Millard F.; Shotts, Zachary; Altgilbers, Larry L.; Stults, Allen H.

2006-04-01

A conventional pulsed power technology has been combined with an explosive pulsed power technology to produce an autonomous high-voltage power supply. The power supply contained an explosive-driven high-voltage primary power source and a power-conditioning stage. The ultracompact explosive-driven primary power source was based on the physical effect of shock-wave depolarization of high-energy Pb (Zr52Ti48)O3 ferroelectric material. The volume of the energy-carrying ferroelectric elements in the shock-wave ferroelectric generators (SWFEGs) varied from 1.2 to 2.6cm3. The power-conditioning stage was based on the spiral vector inversion generator (VIG). The SWFEG-VIG system demonstrated successful operation and good performance. The amplitude of the output voltage pulse of the SWFEG-VIG system exceeded 90kV, with a rise time of 5.2ns.

Proposal and Development of a High Voltage Variable Frequency Alternating Current Power System for Hybrid Electric Aircraft

NASA Technical Reports Server (NTRS)

Sadey, David J.; Taylor, Linda M.; Beach, Raymond F.

2017-01-01

The development of ultra-efficient commercial vehicles and the transition to low-carbon emission propulsion are seen as strategic thrust paths within NASA Aeronautics. A critical enabler to these paths comes in the form of hybrid electric propulsion systems. For megawatt-class systems, the best power system topology for these hybrid electric propulsion systems is debatable. Current proposals within NASA and the Aero community suggest using a combination of alternating current (AC) and direct current (DC) for power generation, transmission, and distribution. This paper proposes an alternative to the current thought model through the use of a primarily high voltage AC power system, supported by the Convergent Aeronautics Solutions (CAS) Project. This system relies heavily on the use of doubly-fed induction machines (DFIMs), which provide high power densities, minimal power conversion, and variable speed operation. The paper presents background on the activity along with the system architecture, development status, and preliminary results.

Upgrade of the TITAN EBIT High Voltage Operation

NASA Astrophysics Data System (ADS)

Foster, Matt; Titan Collaboration

2016-09-01

TRIUMF's Ion Trap for Atomic and Nuclear science (TITAN) is a setup dedicated to highly precise mass measurements of short-lived isotopes down to 10ms. TITAN's Electron Beam Ion Trap (EBIT) is a charge breeder integrated into the setup to perform in-trap decay spectroscopy of highly charged ions and increase the precision of mass measurements. In its previous configuration TITAN's EBIT could not fulfil its maximum design specification due to high voltage safety restrictions, limiting its obtainable charge states. A recently completed upgrade of the high voltage operation that will allow the EBIT to fulfil its design specification and achieve higher charge states for heavier species is undergoing preliminary tests with stable beam. Simulations were performed to optimise the injection and extraction efficiency at high voltage and initial tests have involved using a Ge detector to identify x-rays produced by charge breeding stable ions. Future work comprises exploring electron capture rates of Ne-, He- and H-like charge states of 64Cu and higher masses, which were not previously accessible. The function of the EBIT within the TITAN setup, the work carried out on the upgrade thus far and its scope for future work will be presented.

Cleaning High-Voltage Equipment With Corncob Grit

NASA Technical Reports Server (NTRS)

Caveness, C.

1986-01-01

High electrical resistance of particles makes power shutdown unnecessary. New, inexpensive method of cleaning high-voltage electrical equipment uses plentiful agricultural product - corncob grit. Method removes dirt and debris from transformers, circuit breakers, and similar equipment. Suitable for utilities, large utility customers, and electrical-maintenance services.

Experimental investigation of SDBD plasma actuator driven by AC high voltage with a superimposed positive pulse bias voltage

NASA Astrophysics Data System (ADS)

Qi, Xiao-Hua; Yan, Hui-Jie; Yang, Liang; Hua, Yue; Ren, Chun-Sheng

2017-08-01

In this work, a driven voltage consisting of AC high voltage with a superimposed positive pulse bias voltage ("AC+ Positive pulse bias" voltage) is adopted to study the performance of a surface dielectric barrier discharge plasma actuator under atmospheric conditions. To compare the performance of the actuator driven by single-AC voltage and "AC+ Positive pulse bias" voltage, the actuator-induced thrust force and power consumption are measured as a function of the applied AC voltage, and the measured results indicate that the thrust force can be promoted significantly after superimposing the positive pulse bias voltage. The physical mechanism behind the thrust force changes is analyzed by measuring the optical properties, electrical characteristics, and surface potential distribution. Experimental results indicate that the glow-like discharge in the AC voltage half-cycle, next to the cycle where a bias voltage pulse has been applied, is enhanced after applying the positive pulse bias voltage, and this perhaps is the main reason for the thrust force increase. Moreover, surface potential measurement results reveal that the spatial electric field formed by the surface charge accumulation after positive pulse discharge can significantly affect the applied external electric field, and this perhaps can be responsible for the experimental phenomenon that the decrease of thrust force is delayed by pulse bias voltage action after the filament discharge occurs in the glow-like discharge region. The schlieren images further verify that the actuator-induced airflow velocity increases with the positive pulse voltage.

High-voltage compatible, full-depleted CCD

DOEpatents

Holland, Stephen Edward

2007-09-18

A charge coupled device for detecting electromagnetic and particle radiation is described. The device includes a high-resistivity semiconductor substrate, buried channel regions, gate electrode circuitry, and amplifier circuitry. For good spatial resolution and high performance, especially when operated at high voltages with full or nearly full depletion of the substrate, the device can also include a guard ring positioned near channel regions, a biased channel stop, and a biased polysilicon electrode over the channel stop.

Multiple negative differential resistance devices with ultra-high peak-to-valley current ratio for practical multi-valued logic and memory applications

NASA Astrophysics Data System (ADS)

Shin, Sunhae; Rok Kim, Kyung

2015-06-01

In this paper, we propose a novel multiple negative differential resistance (NDR) device with ultra-high peak-to-valley current ratio (PVCR) over 106 by combining tunnel diode with a conventional MOSFET, which suppresses the valley current with transistor off-leakage level. Band-to-band tunneling (BTBT) in tunnel junction provides the first peak, and the second peak and valley are generated from the suppression of diffusion current in tunnel diode by the off-state MOSFET. The multiple NDR curves can be controlled by doping concentration of tunnel junction and the threshold voltage of MOSFET. By using complementary multiple NDR devices, five-state memory is demonstrated only with six transistors.

The interaction of spacecraft high voltage power systems with the space plasma environment

NASA Technical Reports Server (NTRS)

Domitz, S.; Grier, N. T.

1974-01-01

The development of spacecraft with electrical loads that require high voltage power is discussed. The high voltage solar array has been considered for supplying d.c. power directly to high voltage loads such as ion thrusters and communication tubes without intermediate power processing. Space power stations for transferring solar power to earth are being studied in the 40 kilovolt, multikilowatt regime. Analytical and experimental studies have determined that with the advent of high voltage power, new problems will arise through the interaction of the high voltage surfaces with the charged particle environment of space. The interactive environment has been identified and duplicated to some extent in simulation facilities at NASA-Lewis Research Center and at several contractor locations.

Ultra-high vacuum compatible induction-heated rod casting furnace

NASA Astrophysics Data System (ADS)

Bauer, A.; Neubauer, A.; Münzer, W.; Regnat, A.; Benka, G.; Meven, M.; Pedersen, B.; Pfleiderer, C.

2016-06-01

We report the design of a radio-frequency induction-heated rod casting furnace that permits the preparation of polycrystalline ingots of intermetallic compounds under ultra-high vacuum compatible conditions. The central part of the system is a bespoke water-cooled Hukin crucible supporting a casting mold. Depending on the choice of the mold, typical rods have a diameter between 6 mm and 10 mm and a length up to 90 mm, suitable for single-crystal growth by means of float-zoning. The setup is all-metal sealed and may be baked out. We find that the resulting ultra-high vacuum represents an important precondition for processing compounds with high vapor pressures under a high-purity argon atmosphere up to 3 bars. Using the rod casting furnace, we succeeded to prepare large high-quality single crystals of two half-Heusler compounds, namely, the itinerant antiferromagnet CuMnSb and the half-metallic ferromagnet NiMnSb.

Ultra-high vacuum compatible induction-heated rod casting furnace.

PubMed

Bauer, A; Neubauer, A; Münzer, W; Regnat, A; Benka, G; Meven, M; Pedersen, B; Pfleiderer, C

2016-06-01

We report the design of a radio-frequency induction-heated rod casting furnace that permits the preparation of polycrystalline ingots of intermetallic compounds under ultra-high vacuum compatible conditions. The central part of the system is a bespoke water-cooled Hukin crucible supporting a casting mold. Depending on the choice of the mold, typical rods have a diameter between 6 mm and 10 mm and a length up to 90 mm, suitable for single-crystal growth by means of float-zoning. The setup is all-metal sealed and may be baked out. We find that the resulting ultra-high vacuum represents an important precondition for processing compounds with high vapor pressures under a high-purity argon atmosphere up to 3 bars. Using the rod casting furnace, we succeeded to prepare large high-quality single crystals of two half-Heusler compounds, namely, the itinerant antiferromagnet CuMnSb and the half-metallic ferromagnet NiMnSb.

Rad-Hard, Miniaturized, Scalable, High-Voltage Switching Module for Power Applications Rad-Hard, Miniaturized

NASA Technical Reports Server (NTRS)

Adell, Philippe C.; Mojarradi, Mohammad; DelCastillo, Linda Y.; Vo, Tuan A.

2011-01-01

A paper discusses the successful development of a miniaturized radiation hardened high-voltage switching module operating at 2.5 kV suitable for space application. The high-voltage architecture was designed, fabricated, and tested using a commercial process that uses a unique combination of 0.25 micrometer CMOS (complementary metal oxide semiconductor) transistors and high-voltage lateral DMOS (diffusion metal oxide semiconductor) device with high breakdown voltage (greater than 650 V). The high-voltage requirements are achieved by stacking a number of DMOS devices within one module, while two modules can be placed in series to achieve higher voltages. Besides the high-voltage requirements, a second generation prototype is currently being developed to provide improved switching capabilities (rise time and fall time for full range of target voltages and currents), the ability to scale the output voltage to a desired value with good accuracy (few percent) up to 10 kV, to cover a wide range of high-voltage applications. In addition, to ensure miniaturization, long life, and high reliability, the assemblies will require intensive high-voltage electrostatic modeling (optimized E-field distribution throughout the module) to complete the proposed packaging approach and test the applicability of using advanced materials in a space-like environment (temperature and pressure) to help prevent potential arcing and corona due to high field regions. Finally, a single-event effect evaluation would have to be performed and single-event mitigation methods implemented at the design and system level or developed to ensure complete radiation hardness of the module.

Design and realization of high voltage disconnector condition monitoring system

NASA Astrophysics Data System (ADS)

Shi, Jinrui; Xu, Tianyang; Yang, Shuixian; Li, Buoyang

2017-08-01

The operation status of the high voltage disconnector directly affects the safe and stable operation of the power system. This article uses the wireless frequency hopping communication technology of the communication module to achieve the temperature acquisition of the switch contacts and high voltage bus, to introduce the current value of the loop in ECS, and judge the operation status of the disconnector by considering the ambient temperature, calculating the temperature rise; And through the acquisition of the current of drive motor in the process of switch closing and opening, and fault diagnosis of the disconnector by analyzing the change rule of the drive motor current, the condition monitoring of the high voltage disconnector is realized.

Self-aligned photolithography for the fabrication of fully transparent high-voltage devices

NASA Astrophysics Data System (ADS)

Zhang, Yonghui; Mei, Zengxia; Huo, Wenxing; Wang, Tao; Liang, Huili; Du, Xiaolong

2018-05-01

High-voltage devices, working in the range of hundreds of volts, are indispensable elements in the driving or readout circuits for various kinds of displays, integrated microelectromechanical systems and x-ray imaging sensors. However, the device performances are found hardly uniform or repeatable due to the misalignment issue, which are extremely common for offset drain high-voltage devices. To resolve this issue, this article reports a set of self-aligned photolithography technology for the fabrication of high-voltage devices. High-performance fully-transparent high-voltage thin film transistors, diodes and logic inverters are successfully fabricated with this technology. Unlike other self-aligned routes, opaque masks are introduced on the backside of the transparent substrate to facilitate proximity exposure method. The photolithography process is simulated and analyzed with technology computer aided design simulation to explain the working principle of the proximity exposure method. The substrate thickness is found to be vital for the implementation of this technology based on both simulation and experimental results. The electrical performance of high-voltage devices is dependent on the offset length, which can be delicately modulated by changing the exposure dose. The presented self-aligned photolithography technology is proved to be feasible in high-voltage circuits, demonstrating its huge potential in practical industrial applications.

Recent Developments in High Voltage Research in the United Kingdom

NASA Astrophysics Data System (ADS)

Haddad, A. Manu

This paper gives an overview of research activities in the area of high voltage engineering in UK universities. It summarises the main activities of all active high voltage research groups. Furthermore, current research drivers and funding sources for research in the area are described, and the main initiatives to safeguard the health of the discipline are presented.

Dynamics of laser-guided alternating current high voltage discharges

NASA Astrophysics Data System (ADS)

Daigle, J.-F.; Théberge, F.; Lassonde, P.; Kieffer, J.-C.; Fujii, T.; Fortin, J.; Châteauneuf, M.; Dubois, J.

2013-10-01

The dynamics of laser-guided alternating current high voltage discharges are characterized using a streak camera. Laser filaments were used to trigger and guide the discharges produced by a commercial Tesla coil. The streaking images revealed that the dynamics of the guided alternating current high voltage corona are different from that of a direct current source. The measured effective corona velocity and the absence of leader streamers confirmed that it evolves in a pure leader regime.

High-frequency graphene voltage amplifier.

PubMed

Han, Shu-Jen; Jenkins, Keith A; Valdes Garcia, Alberto; Franklin, Aaron D; Bol, Ageeth A; Haensch, Wilfried

2011-09-14

While graphene transistors have proven capable of delivering gigahertz-range cutoff frequencies, applying the devices to RF circuits has been largely hindered by the lack of current saturation in the zero band gap graphene. Herein, the first high-frequency voltage amplifier is demonstrated using large-area chemical vapor deposition grown graphene. The graphene field-effect transistor (GFET) has a 6-finger gate design with gate length of 500 nm. The graphene common-source amplifier exhibits ∼5 dB low frequency gain with the 3 dB bandwidth greater than 6 GHz. This first AC voltage gain demonstration of a GFET is attributed to the clear current saturation in the device, which is enabled by an ultrathin gate dielectric (4 nm HfO(2)) of the embedded gate structures. The device also shows extrinsic transconductance of 1.2 mS/μm at 1 V drain bias, the highest for graphene FETs using large-scale graphene reported to date.

Working group report on advanced high-voltage high-power and energy-storage space systems

NASA Technical Reports Server (NTRS)

Cohen, H. A.; Cooke, D. L.; Evans, R. W.; Hastings, D.; Jongeward, G.; Laframboise, J. G.; Mahaffey, D.; Mcintyre, B.; Pfizer, K. A.; Purvis, C.

1986-01-01

Space systems in the future will probably include high-voltage, high-power energy-storage and -production systems. Two such technologies are high-voltage ac and dc systems and high-power electrodynamic tethers. The working group identified several plasma interaction phenomena that will occur in the operation of these power systems. The working group felt that building an understanding of these critical interaction issues meant that several gaps in our knowledge had to be filled, and that certain aspects of dc power systems have become fairly well understood. Examples of these current collection are in quiescent plasmas and snap over effects. However, high-voltage dc and almost all ac phenomena are, at best, inadequately understood. In addition, there is major uncertainty in the knowledge of coupling between plasmas and large scale current flows in space plasmas. These gaps in the knowledge are addressed.

Search for Ultra-High Energy Photons with the Pierre Auger Observatory

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

Homola, Piotr

One of key scientific objectives of the Pierre Auger Observatory is the search for ultra-high energy photons. Such photons could originate either in the interactions of energetic cosmic-ray nuclei with the cosmic microwave background (so-called cosmogenic photons) or in the exotic scenarios, e.g. those assuming a production and decay of some hypothetical super-massive particles. The latter category of models would imply relatively large fluxes of photons with ultra-high energies at Earth, while the former, involving interactions of cosmic-ray nuclei with the microwave background - just the contrary: very small fractions. The investigations on the data collected so far in themore » Pierre Auger Observatory led to placing very stringent limits to ultra-high energy photon fluxes: below the predictions of the most of the exotic models and nearing the predicted fluxes of the cosmogenic photons. In this paper the status of these investigations and perspectives for further studies are summarized.« less

An ultra-low-voltage electronic implementation of inertial neuron model with nonmonotonous Liao's activation function.

PubMed

Kant, Nasir Ali; Dar, Mohamad Rafiq; Khanday, Farooq Ahmad

2015-01-01

The output of every neuron in neural network is specified by the employed activation function (AF) and therefore forms the heart of neural networks. As far as the design of artificial neural networks (ANNs) is concerned, hardware approach is preferred over software one because it promises the full utilization of the application potential of ANNs. Therefore, besides some arithmetic blocks, designing AF in hardware is the most important for designing ANN. While attempting to design the AF in hardware, the designs should be compatible with the modern Very Large Scale Integration (VLSI) design techniques. In this regard, the implemented designs should: only be in Metal Oxide Semiconductor (MOS) technology in order to be compatible with the digital designs, provide electronic tunability feature, and be able to operate at ultra-low voltage. Companding is one of the promising circuit design techniques for achieving these goals. In this paper, 0.5 V design of Liao's AF using sinh-domain technique is introduced. Furthermore, the function is tested by implementing inertial neuron model. The performance of the AF and inertial neuron model have been evaluated through simulation results, using the PSPICE software with the MOS transistor models provided by the 0.18-μm Taiwan Semiconductor Manufacturer Complementary Metal Oxide Semiconductor (TSM CMOS) process.

Increase the threshold voltage of high voltage GaN transistors by low temperature atomic hydrogen treatment

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

Erofeev, E. V., E-mail: erofeev@micran.ru; Fedin, I. V.; Kutkov, I. V.

High-electron-mobility transistors (HEMTs) based on AlGaN/GaN epitaxial heterostructures are a promising element base for the fabrication of high voltage electronic devices of the next generation. This is caused by both the high mobility of charge carriers in the transistor channel and the high electric strength of the material, which makes it possible to attain high breakdown voltages. For use in high-power switches, normally off-mode GaN transistors operating under enhancement conditions are required. To fabricate normally off GaN transistors, one most frequently uses a subgate region based on magnesium-doped p-GaN. However, optimization of the p-GaN epitaxial-layer thickness and the doping levelmore » makes it possible to attain a threshold voltage of GaN transistors close to V{sub th} = +2 V. In this study, it is shown that the use of low temperature treatment in an atomic hydrogen flow for the p-GaN-based subgate region before the deposition of gate-metallization layers makes it possible to increase the transistor threshold voltage to V{sub th} = +3.5 V. The effects under observation can be caused by the formation of a dipole layer on the p-GaN surface induced by the effect of atomic hydrogen. The heat treatment of hydrogen-treated GaN transistors in a nitrogen environment at a temperature of T = 250°C for 12 h reveals no degradation of the transistor’s electrical parameters, which can be caused by the formation of a thermally stable dipole layer at the metal/p-GaN interface as a result of hydrogenation.« less

30 CFR 75.705-3 - Work on energized high-voltage surface lines; reporting.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Work on energized high-voltage surface lines... Work on energized high-voltage surface lines; reporting. Any operator designating and assigning qualified persons to perform repairs on energized high-voltage surface lines under the provisions of § 75...

Electrochemical capacitance voltage measurements in highly doped silicon and silicon-germanium alloys

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

Sermage, B.; Essa, Z.; Taleb, N.

2016-04-21

The electrochemical capacitance voltage technique has been used on highly boron doped SiGe and Si layers. Although the boron concentration is constant over the space charge depth, the 1/C{sup 2} versus voltage curves are not linear. They indeed present a negative curvature. This can be explained by the existence of deep acceptors which ionise under a high electric field (large inverse voltage) and not at a low inverse voltage. The measured doping concentration in the electrochemical capacitance voltage increases strongly as the inverse voltage increases. Thanks to a comparison with the boron concentration measured by secondary ions mass spectrometry, wemore » show that the relevant doping concentrations in device layers are obtained for small inverse voltage in agreement with the existence of deep acceptors. At the large inverse voltage, the measured doping can be more than twice larger than the boron concentration measured with a secondary ion mass spectroscopy.« less

High voltage series connected tandem junction solar battery

DOEpatents

Hanak, Joseph J.

1982-01-01

A high voltage series connected tandem junction solar battery which comprises a plurality of strips of tandem junction solar cells of hydrogenated amorphous silicon having one optical path and electrically interconnected by a tunnel junction. The layers of hydrogenated amorphous silicon, arranged in a tandem configuration, can have the same bandgap or differing bandgaps. The tandem junction strip solar cells are series connected to produce a solar battery of any desired voltage.

High-voltage crowbar circuit with cascade-triggered series ignitrons

DOEpatents

Baker, William R. [Orinda, CA

1980-11-04

A series string of ignitrons for switching a large current at high voltage to ground. Switching is initiated by means of a negative trigger pulse applied to the cathode of the lowest voltage level ignitron next to ground to draw ground current through diodes in the ignitor circuit. The trigger pulse is applied thereby to the next higher ignitron cathode and sequentially to the remainder of the ignitrons in the string through diodes in respective ignitor circuits. Full line voltage is held off of nonconducting diodes and ignitrons by means of varistors.

High-voltage crowbar circuit with cascade-triggered series ignitrons

DOEpatents

Baker, W.R.

A series string of ignitrons for switching a large current at high voltage to ground is discussed. Switching is initiated by means of a negative trigger pulse applied to the cathode of the lowest voltage level ignitron next to ground to draw ground current through diodes in the ignitor circuit. The trigger pulse is applied thereby to the next higher ignitron cathode and sequentially to the remainder of the ignitrons in the string through diodes in respective ignitor circuits. Full line voltage is held off of nonconducting diodes and ignitrons by means of varistors.

High-voltage crowbar circuit with cascade-triggered series ignitrons

DOEpatents

Baker, W.R.

1980-11-04

A series string of ignitrons for switching a large current at high voltage to ground. Switching is initiated by means of a negative trigger pulse applied to the cathode of the lowest voltage level ignitron next to ground to draw ground current through diodes in the ignitor circuit. The trigger pulse is applied thereby to the next higher ignitron cathode and sequentially to the remainder of the ignitrons in the string through diodes in respective ignitor circuits. Full line voltage is held off of nonconducting diodes and ignitrons by means of varistors. 1 fig.

Laser beam welding of new ultra-high strength and supra-ductile steels

NASA Astrophysics Data System (ADS)

Dahmen, Martin

2015-03-01

Ultra-high strength and supra-ductile are entering fields of new applications. Those materials are excellent candidates for modern light-weight construction and functional integration. As ultra-high strength steels the stainless martensitic grade 1.4034 and the bainitic steel UNS 53835 are investigated. For the supra-ductile steels stand two high austenitic steels with 18 and 28 % manganese. As there are no processing windows an approach from the metallurgical base on is required. Adjusting the weld microstructure the Q+P and the QT steels require weld heat treatment. The HSD steel is weldable without. Due to their applications the ultra-high strength steels are welded in as-rolled and strengthened condition. Also the reaction of the weld on hot stamping is reflected for the martensitic grades. The supra-ductile steels are welded as solution annealed and work hardened by 50%. The results show the general suitability for laser beam welding.

High Voltage Hybrid Electric Propulsion - Multilayered Functional Insulation System (MFIS) NASA-GRC

NASA Technical Reports Server (NTRS)

Lizcano, M.

2017-01-01

High power transmission cables pose a key challenge in future Hybrid Electric Propulsion Aircraft. The challenge arises in developing safe transmission lines that can withstand the unique environment found in aircraft while providing megawatts of power. High voltage AC, variable frequency cables do not currently exist and present particular electrical insulation challenges since electrical arcing and high heating are more prevalent at higher voltages and frequencies. Identifying and developing materials that maintain their dielectric properties at high voltage and frequencies is crucial.

High voltage pulse ignition of mercury discharge hollow cathodes

NASA Technical Reports Server (NTRS)

Wintucky, E. G.

1973-01-01

A high voltage pulse generated by a capacitor discharge into a step-up transformer has been demonstrated capable of consistently igniting hollow cathode mercury discharges at propellant flows and heater power levels much below those required by conventional cathode starting. Results are presented for 3.2-mm diameter enclosed and open keeper cathodes. Starting characteristics are shown to depend on keeper voltage, mercury flow rate, heater power, keeper orifice size, emissive materials, and electrode to which the pulse is applied. This starting technique has been used to start a cathode over 10,000 times without any degradation of starting capability. The starting reliability, propellant and power savings offered by the high voltage pulse start should favorably impact performance of electron bombardment thrusters in missions requiring many on-off duty cycles.

Experiments with high-voltage insulators in the presence of tritium

NASA Astrophysics Data System (ADS)

Grisham, L. R.; Falter, H.; Causey, R.; Chrisman, W.; Stevenson, T.; Wright, K.

1991-02-01

During the final deuterium-tritium phases of the TFTR and JET tokamaks half of the neutral injectors will be used to produce tritium neutral beams to maintain an equal mix of deuterium and tritium in the core plasma, and such requirements may also occur in future devices. This will require that the voltage hold off capabilities of the high voltage insulators in the accelerators be unimpaired by any charge buildups associated with the beta decay of adsorbed layers. We report tests in which we measured the drain currents under high dc voltage of TFTR and JET accelerator insulators while they were successively exposed to vacuum, deuterium and tritium. There did not appear to be any substantial reduction in hold-off capability with tritium, although at some voltages there was a small increase in the leakage current. We also compared the breakdown properties of a plastic tubing filled with deuterium and then tritium at varying pressures, since such tubing has been considered as a high-voltage break in the gas feed system for TFTR, and the presence of large numbers of electron-ion pairs might lead to enhanced Paschen breakdown. We found no significant differences in the behavior for the geometry used.

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

30 CFR 75.154 - Repair of energized surface high voltage lines; qualified person.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Repair of energized surface high voltage lines... Certified Persons § 75.154 Repair of energized surface high voltage lines; qualified person. An individual... high voltage lines only if he has had at least 2 years experience in electrical maintenance, and at...

Piezoelectric transformer and modular connections for high power and high voltage power supplies

NASA Technical Reports Server (NTRS)

Vazquez Carazo, Alfredo (Inventor)

2006-01-01

A modular design for combining piezoelectric transformers is provided for high voltage and high power conversion applications. The input portions of individual piezoelectric transformers are driven for a single power supply. This created the vibration and the conversion of electrical to electrical energy from the input to the output of the transformers. The output portions of the single piezoelectric transformers are combining in series and/or parallel to provide multiple outputs having different rating of voltage and current.

Highly-flexible, ultra-thin, and transparent single-layer graphene/silver composite electrodes for organic light emitting diodes

NASA Astrophysics Data System (ADS)

Li, Kun; Wang, Hu; Li, Huiying; Li, Ye; Jin, Guangyong; Gao, Lanlan; Marco, Mazzeo; Duan, Yu

2017-08-01

Transparent conductive electrode (TCE) platforms are required in many optoelectronic devices, including organic light emitting diodes (OLEDs). To date, indium tin oxide based electrodes are widely used in TCEs but they still have few limitations in term of achieving flexible OLEDs and display techniques. In this paper, highly-flexible and ultra-thin TCEs were fabricated for use in OLEDs by combining single-layer graphene (SLG) with thin silver layers of only several nanometers in thickness. The as-prepared SLG + Ag (8 nm) composite electrodes showed low sheet resistances of 8.5 Ω/□, high stability over 500 bending cycles, and 74% transmittance at 550 nm wavelength. Furthermore, SLG + Ag composite electrodes employed as anodes in OLEDs delivered turn-on voltages of 2.4 V, with luminance exceeding 1300 cd m-2 at only 5 V, and maximum luminance reaching up 40 000 cd m-2 at 9 V. Also, the devices could work normally under less than the 1 cm bending radius.

30 CFR 77.104 - Repair of energized surface high-voltage lines; qualified person.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Repair of energized surface high-voltage lines... high-voltage lines; qualified person. An individual is a qualified person within the meaning of § 77.704 of this part for the purpose of repairing energized surface high-voltage lines only if he has had...

Effect of pulsed corona discharge voltage and feed gas flow rate on dissolved ozone concentration

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

Prasetyaningrum, A., E-mail: ajiprasetyaningrum@gmail.com; Ratnawati,; Jos, B.

Ozonization is one of the methods extensively used for water purification and degradation of organic materials. Ozone (O{sub 3}) is recognized as a powerful oxidizing agent. Due to its strong oxidability and better environmental friendless, ozone increasing being used in domestic and industrial applications. Current technology in ozone production utilizes several techniques (corona discharge, ultra violet radiation and electrolysis). This experiment aimed to evaluating effect of voltage and gas flow rate on ozone production with corona discharge. The system consists of two net-type stainless steel electrode placed in a dielectric barrier. Three pulsed voltage (20, 30, 40 KV) and flowmore » rate (5, 10, 15 L/min) were prepare for operation variable at high frequency (3.7 kHz) with AC pulsed power supply. The dissolved ozone concentration depends on the applied high-voltage level, gas flow rate and the discharge exposure duration. The ozone concentration increases with decreasing gas flow rate. Dissolved ozone concentrations greater than 200 ppm can be obtained with a minimum voltage 40 kV.« less

Effect of pulsed corona discharge voltage and feed gas flow rate on dissolved ozone concentration

NASA Astrophysics Data System (ADS)

Prasetyaningrum, A.; Ratnawati, Jos, B.

2015-12-01

Ozonization is one of the methods extensively used for water purification and degradation of organic materials. Ozone (O3) is recognized as a powerful oxidizing agent. Due to its strong oxidability and better environmental friendless, ozone increasing being used in domestic and industrial applications. Current technology in ozone production utilizes several techniques (corona discharge, ultra violet radiation and electrolysis). This experiment aimed to evaluating effect of voltage and gas flow rate on ozone production with corona discharge. The system consists of two net-type stainless steel electrode placed in a dielectric barrier. Three pulsed voltage (20, 30, 40 KV) and flow rate (5, 10, 15 L/min) were prepare for operation variable at high frequency (3.7 kHz) with AC pulsed power supply. The dissolved ozone concentration depends on the applied high-voltage level, gas flow rate and the discharge exposure duration. The ozone concentration increases with decreasing gas flow rate. Dissolved ozone concentrations greater than 200 ppm can be obtained with a minimum voltage 40 kV.

Efficiency and weight of voltage multiplier type ultra lightweight dc-dc converters

NASA Technical Reports Server (NTRS)

Harrigill, W. T., Jr.; Myers, I. T.

1975-01-01

An analytical and experimental study was made of a capacitor-diode voltage multiplier without a transformer which offers the possibility of high efficiency with light weight. The dc-dc conversion efficiencies of about 94 percent were achieved at output powers of 150 watts at 1000 volts using 8x multiplication. A detailed identification of losses was made, including forward drop losses in component, switching losses, reverse junction capacitance charging losses, and charging losses in the main ladder capacitors.

Adjustable, High Voltage Pulse Generator with Isolated Output for Plasma Processing

NASA Astrophysics Data System (ADS)

Ziemba, Timothy; Miller, Kenneth E.; Prager, James; Slobodov, Ilia

2015-09-01

Eagle Harbor Technologies (EHT), Inc. has developed a high voltage pulse generator with isolated output for etch, sputtering, and ion implantation applications within the materials science and semiconductor processing communities. The output parameters are independently user adjustable: output voltage (0 - 2.5 kV), pulse repetition frequency (0 - 100 kHz), and duty cycle (0 - 100%). The pulser can drive loads down to 200 Ω. Higher voltage pulsers have also been tested. The isolated output allows the pulse generator to be connected to loads that need to be biased. These pulser generators take advantage modern silicon carbide (SiC) MOSFETs. These new solid-state switches decrease the switching and conduction losses while allowing for higher switching frequency capabilities. This pulse generator has applications for RF plasma heating; inductive and arc plasma sources; magnetron driving; and generation of arbitrary pulses at high voltage, high current, and high pulse repetition frequency. This work was supported in part by a DOE SBIR.

New-type steel plate with ultra high crack-arrestability

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

Ishikawa, T.; Nomiyama, Y.; Hagiwara, Y.

1995-12-31

A new-type steel plate has been developed by controlling the microstructure of the surface layers. The surface layer consists of ultra fine grain ferrite microstructure, which provides excellent fracture toughness even at cryogenic temperature. When an unstable brittle crack propagates in the developed steel plate, shear-lips can be easily formed due to the surface layers with ultra fine grain microstructure. Since unstable running crack behavior is strongly affected by side-ligaments (shear-lips), which are associated with extensive plastic deformation, enhanced formation of the shear-lips can improve crack arrestability. This paper describes the developed steel plates of HT500MPa tensile strength class formore » shipbuilding use. Fracture mechanics investigations using large-scale fracture testings (including ultrawide duplex ESSO tests) clarified that the developed steel plates have ultra high crack-arrestability. It was also confirmed that the plates possess sufficient properties, including weldability and workability, for ship building use.« less

Planar LTCC transformers for high voltage flyback converters: Part II.

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

Schofield, Daryl; Schare, Joshua M., Ph.D.; Slama, George

This paper is a continuation of the work presented in SAND2007-2591 'Planar LTCC Transformers for High Voltage Flyback Converters'. The designs in that SAND report were all based on a ferrite tape/dielectric paste system originally developed by NASCENTechnoloy, Inc, who collaborated in the design and manufacturing of the planar LTCC flyback converters. The output/volume requirements were targeted to DoD application for hard target/mini fuzing at around 1500 V for reasonable primary peak currents. High voltages could be obtained but with considerable higher current. Work had begun on higher voltage systems and is where this report begins. Limits in material propertiesmore » and processing capabilities show that the state-of-the-art has limited our practical output voltage from such a small part volume. In other words, the technology is currently limited within the allowable funding and interest.« less

Application of ultra-high performance concrete to bridge girders.

DOT National Transportation Integrated Search

2009-02-01

"Ultra-High Performance Concrete (UHPC) is a new class of concrete that has superior performance characteristics : compared to conventional concrete. The enhanced strength and durability properties of UHPC are mainly due to optimized : particle grada...

Fiber optic current monitor for high-voltage applications

DOEpatents

Renda, G.F.

1992-04-21

A current monitor which derives its power from the conductor being measured for bidirectionally measuring the magnitude of current (from DC to above 50 khz) flowing through a conductor across which a relatively high level DC voltage is applied, includes a pair of identical transmitter modules connected in opposite polarity to one another in series with the conductor being monitored, for producing from one module a first light signal having an intensity directly proportional to the magnitude of current flowing in one direction through the conductor during one period of time, and from the other module a second light signal having an intensity directly proportional to the magnitude of current flowing in the opposite direction through the conductor during another period of time, and a receiver located in a safe area remote from the high voltage area for receiving the first and second light signals, and converting the same to first and second voltage signals having levels indicative of the magnitude of current being measured at a given time. 6 figs.

Fiber optic current monitor for high-voltage applications

DOEpatents

Renda, George F.

1992-01-01

A current monitor which derives its power from the conductor being measured for bidirectionally measuring the magnitude of current (from DC to above 50 khz) flowing through a conductor across which a relatively high level DC voltage is applied, includes a pair of identical transmitter modules connected in opposite polarity to one another in series with the conductor being monitored, for producing from one module a first light signal having an intensity directly proportional to the magnitude of current flowing in one direction through the conductor during one period of time, and from the other module a second light signal having an intensity directly proportional to the magnitude of current flowing in the opposite direction through the conductor during another period of time, and a receiver located in a safe area remote from the high voltage area for receiving the first and second light signals, and converting the same to first and second voltage signals having levels indicative of the magnitude of current being measured at a given time.

Design techniques for low-voltage analog integrated circuits

NASA Astrophysics Data System (ADS)

Rakús, Matej; Stopjaková, Viera; Arbet, Daniel

2017-08-01

In this paper, a review and analysis of different design techniques for (ultra) low-voltage integrated circuits (IC) are performed. This analysis shows that the most suitable design methods for low-voltage analog IC design in a standard CMOS process include techniques using bulk-driven MOS transistors, dynamic threshold MOS transistors and MOS transistors operating in weak or moderate inversion regions. The main advantage of such techniques is that there is no need for any modification of standard CMOS structure or process. Basic circuit building blocks like differential amplifiers or current mirrors designed using these approaches are able to operate with the power supply voltage of 600 mV (or even lower), which is the key feature towards integrated systems for modern portable applications.

Study on creep of fiber reinforced ultra-high strength concrete based on strength

NASA Astrophysics Data System (ADS)

Peng, Wenjun; Wang, Tao

2018-04-01

To complement the creep performance of ultra-high strength concrete, the long creep process of fiber reinforced concrete was studied in this paper. The long-term creep process and regularity of ultra-high strength concrete with 0.5% PVA fiber under the same axial compression were analyzed by using concrete strength (C80/C100/C120) as a variable. The results show that the creep coefficient of ultra-high strength concrete decreases with the increase of concrete strength. Compared with ACI209R (92), GL2000 models, it is found that the predicted value of ACI209R (92) are close to the experimental value, and the creep prediction model suitable for this experiment is proposed based on ACI209R (92).

30 CFR 57.12071 - Movement or operation of equipment near high-voltage powerlines.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Movement or operation of equipment near high-voltage powerlines. 57.12071 Section 57.12071 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION...-voltage powerlines. When equipment must be moved or operated near energized high-voltage powerlines (other...

An Inexpensive Source of High Voltage

ERIC Educational Resources Information Center

Saraiva, Carlos

2012-01-01

As a physics teacher I like recycling old apparatus and using them for demonstrations in my classes. In physics laboratories in schools, sources of high voltage include induction coils or electronic systems that can be bought from companies that sell lab equipment. But these sources can be very expensive. In this article, I will explain how you…

TRANSISTOR HIGH VOLTAGE POWER SUPPLY

DOEpatents

Driver, G.E.

1958-07-15

High voltage, direct current power supplies are described for use with battery powered nuclear detection equipment. The particular advantages of the power supply described, are increased efficiency and reduced size and welght brought about by the use of transistors in the circuit. An important feature resides tn the employment of a pair of transistors in an alternatefiring oscillator circuit having a coupling transformer and other circuit components which are used for interconnecting the various electrodes of the transistors.

Liquid crystal modulator with ultra-wide dynamic range and adjustable driving voltage.

PubMed

Wang, Xing-jun; Huang, Zhang-di; Feng, Jing; Chen, Xiang-fei; Liang, Xiao; Lu, Yan-qing

2008-08-18

We demonstrated a reflective-type liquid crystal (LC) intensity modulator in 1550 nm telecomm band. An effective way to compensate the residual phase of a LC cell is proposed. With the adjustment of a true zero-order quarter wave plate and enhanced by total internal reflection induced birefringence, over 53 dB dynamic range was achieved, which is much desired for some high-end optical communication, infrared scene projection applications. In addition, the driving voltages were decreased and adjustable. Mechanical and spectral tolerance measurements show that our LC modulator is quite stable. Further applications of our experimental setup were discussed including bio-sensors and high speed modulators.

A high voltage electrical power system for low Earth orbit applications

NASA Technical Reports Server (NTRS)

Lanier, J. R., Jr.; Bush, J. R., Jr.

1984-01-01

The results of testing a high voltage electrical power system (EPS) breadboard using high voltage power processing equipment developed at Marshall Space Flight Center and Ni-Cd batteries are discussed. These test results are used to extrapolate to an efficient, reliable, high capacity EPS for near term low Earth orbit, high power applications. EPS efficiencies, figures of merit, and battery reliability with a battery protection and reconditioning circuit are presented.

Field Evaluation of Ultra-High Pressure Water Systems for Runway Rubber Removal

DTIC Science & Technology

2014-04-01

ER D C/ G SL T R- 14 -1 1 Field Evaluation of Ultra-High Pressure Water Systems for Runway Rubber Removal G eo te ch ni ca l a nd S tr...Field Evaluation of Ultra-High Pressure Water Systems for Runway Rubber Removal Aaron B. Pullen Applied Research Associates, Inc. 421 Oak Avenue...collaboration with Applied Research Associates, Inc. (ARA). Several types of commercial UHPW water blasting systems were tested on an ungrooved portland cement

Cermet insert high voltage holdoff for ceramic/metal vacuum devices

DOEpatents

Ierna, William F.

1987-01-01

An improved metal-to-ceramic seal is provided wherein the ceramic body of the seal contains an integral region of cermet material in electrical contact with the metallic member, e.g., an electrode, of the seal. The seal is useful in high voltage vacuum devices, e.g., vacuum switches, and increases the high-voltage holdoff capabilities of such devices. A method of fabricating such seals is also provided.

Bond behavior of reinforcing steel in ultra-high performance concrete.

DOT National Transportation Integrated Search

2014-10-01

Ultra-High Performance Concrete (UHPC) is a relatively new class of advanced cementitious composite : materials, which exhibits high compressive [above 21.7 ksi (150 MPa)] and tensile [above 0.72 ksi (5 MPa)] : strengths. The discrete steel fiber rei...

Electronic Current Transducer (ECT) for high voltage dc lines

NASA Astrophysics Data System (ADS)

Houston, J. M.; Peters, P. H., Jr.; Summerayes, H. R., Jr.; Carlson, G. J.; Itani, A. M.

1980-02-01

The development of a bipolar electronic current transducer (ECT) for measuring the current in a high voltage dc (HVDC) power line at line potential is discussed. The design and construction of a free standing ECT for use on a 400 kV line having a nominal line current of 2000 A is described. Line current is measured by a 0.0001 ohm shunt whose voltage output is sampled by a 14 bit digital data link. The high voltage interface between line and ground is traversed by optical fibers which carry digital light signals as far as 300 m to a control room where the digital signal is converted back to an analog representation of the shunt voltage. Two redundant electronic and optical data links are used in the prototype. Power to operate digital and optical electronics and temperature controlling heaters at the line is supplied by a resistively and capacitively graded 10 stage cascade of ferrite core transformers located inside the hollow, SF6 filled, porcelain support insulator. The cascade is driven by a silicon controlled rectifier inverter which supplies about 100 W of power at 30 kHz.

The development of a portable ultrahigh vacuum chamber via silicon block.

PubMed

Chuang, Ho-Chiao; Huang, Chia-Shiuan

2014-05-01

This paper describes a nonmetallic, light weight portable chamber for ultra-high vacuum (UHV) applications. The chamber consists of a processed silicon block anodically bonding five polished Pyrex glass windows and a Pyrex glass adapter, without using any screws, bolts or vacuum adhesives. The design features provide an alternative chamber for UHV applications which require nonmetallic components. We have cyclically baked the chamber up to 180 °C for 160 h and have achieved an ultimate pressure of 1.4 × 10(-9) Torr (limited by our pumping station), with no leak detected. Both Pyrex glass windows and Pyrex glass adapter have been used successfully.

Atypical Exit Wound in High-Voltage Electrocution.

PubMed

Parakkattil, Jamshid; Kandasamy, Shanmugam; Das, Siddhartha; Devnath, Gerard Pradeep; Chaudhari, Vinod Ashok; Shaha, Kusa Kumar

2017-12-01

Electrocution fatality cases are difficult to investigate. High-voltage electrocution burns resemble burns caused by other sources, especially if the person survives for few days. In that case, circumstantial evidence if correlated with the autopsy findings helps in determining the cause and manner of death. In addition, the crime scene findings also help to explain the pattern of injuries observed at autopsy. A farmer came in contact with a high-voltage transmission wire and sustained superficial to deep burns over his body. A charred and deeply scorched area was seen over the face, which was suggestive of the electric entry wound. The exit wound was present over both feet and lower leg and was atypical in the form of a burnt area of peeled blistered skin, charring, and deep scorching. The injuries were correlated with crime scene findings, and the circumstances that lead to his electrocution are discussed here.

30 CFR 75.511 - Low-, medium-, or high-voltage distribution circuits and equipment; repair.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Low-, medium-, or high-voltage distribution... Electrical Equipment-General § 75.511 Low-, medium-, or high-voltage distribution circuits and equipment; repair. [Statutory Provision] No electrical work shall be performed on low-, medium-, or high-voltage...

30 CFR 75.511 - Low-, medium-, or high-voltage distribution circuits and equipment; repair.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Low-, medium-, or high-voltage distribution... Electrical Equipment-General § 75.511 Low-, medium-, or high-voltage distribution circuits and equipment; repair. [Statutory Provision] No electrical work shall be performed on low-, medium-, or high-voltage...

30 CFR 75.511 - Low-, medium-, or high-voltage distribution circuits and equipment; repair.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Low-, medium-, or high-voltage distribution... Electrical Equipment-General § 75.511 Low-, medium-, or high-voltage distribution circuits and equipment; repair. [Statutory Provision] No electrical work shall be performed on low-, medium-, or high-voltage...

30 CFR 75.511 - Low-, medium-, or high-voltage distribution circuits and equipment; repair.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Low-, medium-, or high-voltage distribution... Electrical Equipment-General § 75.511 Low-, medium-, or high-voltage distribution circuits and equipment; repair. [Statutory Provision] No electrical work shall be performed on low-, medium-, or high-voltage...

30 CFR 75.511 - Low-, medium-, or high-voltage distribution circuits and equipment; repair.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Low-, medium-, or high-voltage distribution... Electrical Equipment-General § 75.511 Low-, medium-, or high-voltage distribution circuits and equipment; repair. [Statutory Provision] No electrical work shall be performed on low-, medium-, or high-voltage...

High voltage isolation transformer

NASA Astrophysics Data System (ADS)

Clatterbuck, C. H.; Ruitberg, A. P.

1985-04-01

A high voltage isolation transformer is provided with primary and secondary coils separated by discrete electrostatic shields from the surfaces of insulating spools on which the coils are wound. The electrostatic shields are formed by coatings of a compound with a low electrical conductivity which completely encase the coils and adhere to the surfaces of the insulating spools adjacent to the coils. Coatings of the compound also line axial bores of the spools, thereby forming electrostatic shields separating the spools from legs of a ferromagnetic core extending through the bores. The transformer is able to isolate a high constant potential applied to one of its coils, without the occurrence of sparking or corona, by coupling the coatings, lining the axial bores to the ferromagnetic core and by coupling one terminal of each coil to the respective coating encasing the coil.

High voltage isolation transformer

NASA Technical Reports Server (NTRS)

Clatterbuck, C. H.; Ruitberg, A. P. (Inventor)

1985-01-01

A high voltage isolation transformer is provided with primary and secondary coils separated by discrete electrostatic shields from the surfaces of insulating spools on which the coils are wound. The electrostatic shields are formed by coatings of a compound with a low electrical conductivity which completely encase the coils and adhere to the surfaces of the insulating spools adjacent to the coils. Coatings of the compound also line axial bores of the spools, thereby forming electrostatic shields separating the spools from legs of a ferromagnetic core extending through the bores. The transformer is able to isolate a high constant potential applied to one of its coils, without the occurrence of sparking or corona, by coupling the coatings, lining the axial bores to the ferromagnetic core and by coupling one terminal of each coil to the respective coating encasing the coil.

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

Makarov, Yuri V.; Du, Pengwei; Etingov, Pavel V.

The document titled “WECC Variable Generation Planning Reference Book”. This book is divided into two volumes; one is the main document (volume 1)and the other is appendices (volume 2). The main document is a collection of the best practices and the information regarding the application and impact of variables generation on power system planning. This volume (appendices) has additional information on the following topics: Probabilistic load flow problems. 2. Additional useful indices. 3. high-impact low-frequency (HILF) events. 4. Examples of wide-area nomograms. 5. Transmission line ratings, types of dynamic rating methods. 6. Relative costs per MW-km of different electric powermore » transmission technologies. 7. Ultra-high voltage (UHV) transmission. 8.High voltage direct current (VSC-HVDC). 9. HVDC. 10. Rewiring of existing transmission lines. 11. High-temperature low sag (HTLS) conductors. 12. The direct method and energy functions for transient stability analysis in power systems. 13.Blackouts caused by voltage instability. 14. Algorithm for parameter continuation predictor-corrector methods. 15. Approximation techniques available for security regions. 16. Impacts of wind power on power system small signals stability. 17. FIDVR. 18. FACTS. 19. European planning standard and practices. 20. International experience in wind and solar energy sources. 21. Western Renewable Energy Zones (WREZ). 22. various energy storage technologies. 23. demand response. 24. BA consolidation and cooperation options. 25. generator power management requirements and 26. European planning guidelines.« less

High Voltage, Solid-State Switch for Fusion Science Applications

NASA Astrophysics Data System (ADS)

Ziemba, Timothy; Prager, James; Miller, Kenneth E.; Slobodov, Ilia

2017-10-01

Eagle Harbor Technologies, Inc. is developing a series stack of solid-state switches to produce a single high voltage switch that can be operated at over 35 kV. During the Phase I program, EHT developed two high voltage switch modules: one with isolated power gate drive and a second with inductively coupled gate drive. These switches were tested at 15 kV and up to 300 A at switching frequencies up to 500 kHz for 10 ms bursts. Robust switching was demonstrated for both IGBTs and SiC MOSFETs. During the Phase II program, EHT will develop a higher voltage switch (>35 kV) that will be suitable for high pulsed and average power applications. EHT will work with LTX to utilize these switches to design, build, and test a pulsed magnetron driver that will be delivered to LTX before the completion of the program. EHT will present data from the Phase I program as well as preliminary results from the start of the Phase II program. With support of DOE SBIR.

30 CFR 77.704-3 - Work on energized high-voltage surface lines; reporting.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Work on energized high-voltage surface lines... OF UNDERGROUND COAL MINES Grounding § 77.704-3 Work on energized high-voltage surface lines...-voltage surface lines under the provisions of § 77.704-2 shall maintain a record of such repairs. Such...

Vacuum Bloch-Siegert shift in Landau polaritons with ultra-high cooperativity

NASA Astrophysics Data System (ADS)

Li, Xinwei; Bamba, Motoaki; Zhang, Qi; Fallahi, Saeed; Gardner, Geoff C.; Gao, Weilu; Lou, Minhan; Yoshioka, Katsumasa; Manfra, Michael J.; Kono, Junichiro

2018-06-01

A two-level system resonantly interacting with an a.c. magnetic or electric field constitutes the physical basis of diverse phenomena and technologies. However, Schrödinger's equation for this seemingly simple system can be solved exactly only under the rotating-wave approximation, which neglects the counter-rotating field component. When the a.c. field is sufficiently strong, this approximation fails, leading to a resonance-frequency shift known as the Bloch-Siegert shift. Here, we report the vacuum Bloch-Siegert shift, which is induced by the ultra-strong coupling of matter with the counter-rotating component of the vacuum fluctuation field in a cavity. Specifically, an ultra-high-mobility two-dimensional electron gas inside a high-Q terahertz cavity in a quantizing magnetic field revealed ultra-narrow Landau polaritons, which exhibited a vacuum Bloch-Siegert shift up to 40 GHz. This shift, clearly distinguishable from the photon-field self-interaction effect, represents a unique manifestation of a strong-field phenomenon without a strong field.

Ultra high vacuum seal arrangement

DOEpatents

Flaherty, Robert

1981-01-01

Arrangement for demountably sealing two concentric metallic tubes in an ultra high vacuum system which facilitates remote actuation. A tubular seal includes integral spaced lips which circumferentially engage the metallic tubes. The lips plastically deform the metallic tubes by mechanical forces resulting from a martensite to austenite transformation of the tubular seal upon application of a predetermined temperature. The sealing force is released upon application of another temperature which causes a transformation from the stronger austenite to the weaker martensite. Use of a dual acting sealing ring and driving ring circumferentially contacting the sealing ring is particularly applicable to sealing larger diameter concentric metallic members.

Observation of Dust Stream Formation Produced by Low Current, High Voltage Cathode Spots

NASA Technical Reports Server (NTRS)

Foster, John E.

2004-01-01

Macro-particle acceleration driven by low current, high voltage cathode spots has been investigated. The phenomenon was observed to occur when nanometer and micrometer-sized particles in the presence of a discharge plasma were exposed to a high voltage pulse. The negative voltage pulse initiates the formation of multiple, high voltage, low current cathode spots which provides the mechanism of actual acceleration of the charged dust particles. Dust streams generated by this process were detected using laser scattering techniques. The particle impact craters observed at the surface of downstream witness badges were documented using SEM and light microscopy.

High-voltage pulsed generator for dynamic fragmentation of rocks

NASA Astrophysics Data System (ADS)

Kovalchuk, B. M.; Kharlov, A. V.; Vizir, V. A.; Kumpyak, V. V.; Zorin, V. B.; Kiselev, V. N.

2010-10-01

A portable high-voltage (HV) pulsed generator has been designed for rock fragmentation experiments. The generator can be used also for other technological applications. The installation consists of low voltage block, HV block, coaxial transmission line, fragmentation chamber, and control system block. Low voltage block of the generator, consisting of a primary capacitor bank (300 μF) and a thyristor switch, stores pulse energy and transfers it to the HV block. The primary capacitor bank stores energy of 600 J at the maximum charging voltage of 2 kV. HV block includes HV pulsed step up transformer, HV capacitive storage, and two electrode gas switch. The following technical parameters of the generator were achieved: output voltage up to 300 kV, voltage rise time of ˜50 ns, current amplitude of ˜6 kA with the 40 Ω active load, and ˜20 kA in a rock fragmentation regime (with discharge in a rock-water mixture). Typical operation regime is a burst of 1000 pulses with a frequency of 10 Hz. The operation process can be controlled within a wide range of parameters. The entire installation (generator, transmission line, treatment chamber, and measuring probes) is designed like a continuous Faraday's cage (complete shielding) to exclude external electromagnetic perturbations.

High-voltage pulsed generator for dynamic fragmentation of rocks.

PubMed

Kovalchuk, B M; Kharlov, A V; Vizir, V A; Kumpyak, V V; Zorin, V B; Kiselev, V N

2010-10-01

A portable high-voltage (HV) pulsed generator has been designed for rock fragmentation experiments. The generator can be used also for other technological applications. The installation consists of low voltage block, HV block, coaxial transmission line, fragmentation chamber, and control system block. Low voltage block of the generator, consisting of a primary capacitor bank (300 μF) and a thyristor switch, stores pulse energy and transfers it to the HV block. The primary capacitor bank stores energy of 600 J at the maximum charging voltage of 2 kV. HV block includes HV pulsed step up transformer, HV capacitive storage, and two electrode gas switch. The following technical parameters of the generator were achieved: output voltage up to 300 kV, voltage rise time of ∼50 ns, current amplitude of ∼6 kA with the 40 Ω active load, and ∼20 kA in a rock fragmentation regime (with discharge in a rock-water mixture). Typical operation regime is a burst of 1000 pulses with a frequency of 10 Hz. The operation process can be controlled within a wide range of parameters. The entire installation (generator, transmission line, treatment chamber, and measuring probes) is designed like a continuous Faraday's cage (complete shielding) to exclude external electromagnetic perturbations.

Design of Ultra-High-Power-Density Machine Optimized for Future Aircraft

NASA Technical Reports Server (NTRS)

Choi, Benjamin B.

2004-01-01

The NASA Glenn Research Center's Structural Mechanics and Dynamics Branch is developing a compact, nonpolluting, bearingless electric machine with electric power supplied by fuel cells for future "more-electric" aircraft with specific power in the projected range of 50 hp/lb, whereas conventional electric machines generate usually 0.2 hp/lb. The use of such electric drives for propulsive fans or propellers depends on the successful development of ultra-high-power-density machines. One possible candidate for such ultra-high-power-density machines, a round-rotor synchronous machine with an engineering current density as high as 20,000 A/sq cm, was selected to investigate how much torque and power can be produced.

Review of Adult Electrical Burn Injury Outcomes Worldwide: An Analysis of Low-Voltage vs High-Voltage Electrical Injury.

PubMed

Shih, Jessica G; Shahrokhi, Shahriar; Jeschke, Marc G

The aims of this article are to review low-voltage vs high-voltage electrical burn complications in adults and to identify novel areas that are not recognized to improve outcomes. An extensive literature search on electrical burn injuries was performed using OVID MEDLINE, PubMed, and EMBASE databases from 1946 to 2015. Studies relating to outcomes of electrical injury in the adult population (≥18 years of age) were included in the study. Forty-one single-institution publications with a total of 5485 electrical injury patients were identified and included in the present study. Fourty-four percent of these patients were low-voltage injuries (LVIs), 38.3% high-voltage injuries (HVIs), and 43.7% with voltage not otherwise specified. Forty-four percentage of studies did not characterize outcomes according to LHIs vs HVIs. Reported outcomes include surgical, medical, posttraumatic, and others (long-term/psychological/rehabilitative), all of which report greater incidence rates in HVI than in LVI. Only two studies report on psychological outcomes such as posttraumatic stress disorder. Mortality rates from electrical injuries are 2.6% in LVI, 5.2% in HVI, and 3.7% in not otherwise specified. Coroner's reports revealed a ratio of 2.4:1 for deaths caused by LVI compared with HVI. HVIs lead to greater morbidity and mortality than LVIs. However, the results of the coroner's reports suggest that immediate mortality from LVI may be underestimated. Furthermore, on the basis of this analysis, we conclude that the majority of studies report electrical injury outcomes; however, the majority of them do not analyze complications by low vs high voltage and often lack long-term psychological and rehabilitation outcomes after electrical injury indicating that a variety of central aspects are not being evaluated or assessed.

Recent advances of high voltage AlGaN/GaN power HFETs

NASA Astrophysics Data System (ADS)

Uemoto, Yasuhiro; Ueda, Tetsuzo; Tanaka, Tsuyoshi; Ueda, Daisuke

2009-02-01

We review our recent advances of GaN-based high voltage power transistors. These are promising owing to low on-state resistance and high breakdown voltage taking advantages of superior material properties. However, there still remain a couple of technical issues to be solved for the GaN devices to replace the existing Si-based power devices. The most critical issue is to achieve normally-off operation which is strongly desired for the safety operation, however, it has been very difficult because of the built-in polarization electric field. Our new device called GIT (Gate Injection Transistor) utilizing conductivity modulation successfully achieves the normally-off operation keeping low on-state resistance. The fabricated GIT on a Si substrate exhibits threshold voltage of +1.0V. The obtained on-state resistance and off-state breakdown voltage were 2.6mΩ•cm2 and 800V, respectively. Remaining technical issue is to further increase the breakdown voltage. So far, the reported highest off-state breakdown voltage of AlGaN/GaN HFETs has been 1900V. Overcoming these issues by a novel device structure, we have demonstrated the world highest breakdown voltages of 10400V using thick poly-crystalline AlN as a passivation film and Via-holes through sapphire which enable very efficient layout of the lateral HFET array avoiding any undesired breakdown of passivation films. Since conventional wet or dry etching cannot be used for chemically stable sapphire, high power pulsed laser is used to form the via-holes. The presented GaN power devices demonstrate that GaN is advantageous for high voltage power switching applications replacing currently used Si-based power MOSFETs and IGBTs.

30 CFR 75.812-2 - High-voltage power centers and transformers; record of examination.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false High-voltage power centers and transformers; record of examination. 75.812-2 Section 75.812-2 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... High-Voltage Distribution § 75.812-2 High-voltage power centers and transformers; record of examination...

30 CFR 75.812-2 - High-voltage power centers and transformers; record of examination.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false High-voltage power centers and transformers; record of examination. 75.812-2 Section 75.812-2 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... High-Voltage Distribution § 75.812-2 High-voltage power centers and transformers; record of examination...

30 CFR 75.812-2 - High-voltage power centers and transformers; record of examination.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false High-voltage power centers and transformers; record of examination. 75.812-2 Section 75.812-2 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... High-Voltage Distribution § 75.812-2 High-voltage power centers and transformers; record of examination...

30 CFR 75.812-2 - High-voltage power centers and transformers; record of examination.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-voltage power centers and transformers; record of examination. 75.812-2 Section 75.812-2 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... High-Voltage Distribution § 75.812-2 High-voltage power centers and transformers; record of examination...

30 CFR 75.812-2 - High-voltage power centers and transformers; record of examination.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false High-voltage power centers and transformers; record of examination. 75.812-2 Section 75.812-2 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... High-Voltage Distribution § 75.812-2 High-voltage power centers and transformers; record of examination...

Compact low temperature scanning tunneling microscope with in-situ sample preparation capability.

PubMed

Kim, Jungdae; Nam, Hyoungdo; Qin, Shengyong; Kim, Sang-ui; Schroeder, Allan; Eom, Daejin; Shih, Chih-Kang

2015-09-01

We report on the design of a compact low temperature scanning tunneling microscope (STM) having in-situ sample preparation capability. The in-situ sample preparation chamber was designed to be compact allowing quick transfer of samples to the STM stage, which is ideal for preparing temperature sensitive samples such as ultra-thin metal films on semiconductor substrates. Conventional spring suspensions on the STM head often cause mechanical issues. To address this problem, we developed a simple vibration damper consisting of welded metal bellows and rubber pads. In addition, we developed a novel technique to ensure an ultra-high-vacuum (UHV) seal between the copper and stainless steel, which provides excellent reliability for cryostats operating in UHV. The performance of the STM was tested from 2 K to 77 K by using epitaxial thin Pb films on Si. Very high mechanical stability was achieved with clear atomic resolution even when using cryostats operating at 77 K. At 2 K, a clean superconducting gap was observed, and the spectrum was easily fit using the BCS density of states with negligible broadening.

High voltage and high current density vertical GaN power diodes

DOE PAGES

Fischer, A. J.; Dickerson, J. R.; Armstrong, A. M.; ...

2016-01-01

We report on the realization of a GaN high voltage vertical p-n diode operating at > 3.9 kV breakdown with a specific on-resistance < 0.9 mΩ.cm 2. Diodes achieved a forward current of 1 A for on-wafer, DC measurements, corresponding to a current density > 1.4 kA/cm 2. An effective critical electric field of 3.9 MV/cm was estimated for the devices from analysis of the forward and reverse current-voltage characteristics. Furthermore this suggests that the fundamental limit to the GaN critical electric field is significantly greater than previously believed.

Optically triggered high voltage switch network and method for switching a high voltage

DOEpatents

El-Sharkawi, Mohamed A.; Andexler, George; Silberkleit, Lee I.

1993-01-19

An optically triggered solid state switch and method for switching a high voltage electrical current. A plurality of solid state switches (350) are connected in series for controlling electrical current flow between a compensation capacitor (112) and ground in a reactive power compensator (50, 50') that monitors the voltage and current flowing through each of three distribution lines (52a, 52b and 52c), which are supplying three-phase power to one or more inductive loads. An optical transmitter (100) controlled by the reactive power compensation system produces light pulses that are conveyed over optical fibers (102) to a switch driver (110') that includes a plurality of series connected optical triger circuits (288). Each of the optical trigger circuits controls a pair of the solid state switches and includes a plurality of series connected resistors (294, 326, 330, and 334) that equalize or balance the potential across the plurality of trigger circuits. The trigger circuits are connected to one of the distribution lines through a trigger capacitor (340). In each switch driver, the light signals activate a phototransistor (300) so that an electrical current flows from one of the energy reservoir capacitors through a pulse transformer (306) in the trigger circuit, producing gate signals that turn on the pair of serially connected solid state switches (350).

Spatially-Resolved Characterization Techniques to Investigate Impact Damage in Ultra-High Performance Concretes

DTIC Science & Technology

2013-04-01

Concretes G eo te ch n ic al a n d S tr u ct u re s La b or at or y Robert D. Moser, Paul G. Allison, and Mei Q. Chandler April 2013 Approved...Impact Damage in Ultra-High Performance Concretes Robert D. Moser, Paul G. Allison, and Mei Q. Chandler Geotechnical and Structures Laboratory US...Portland Cement concrete (OPC) and Ultra-High Performance Concretes (UHPCs) under high-strain impact and penetration loads at lower length scales

High-voltage nano-oxidation in deionized water and atmospheric environments by atomic force microscopy.

PubMed

Huang, Jen-Ching; Chen, Chung-Ming

2012-01-01

This study used atomic force microscopy (AFM), metallic probes with a nanoscale tip, and high-voltage generators to investigate the feasibility of high-voltage nano-oxidation processing in deionized water (DI water) and atmospheric environments. Researchers used a combination of wire-cutting and electrochemical etching to transform a 20-μm-thick stainless steel sheet into a conductive metallic AFM probe with a tip radius of 60 nm, capable of withstanding high voltages. The combination of AFM, high-voltage generators, and nanoscale metallic probes enabled nano-oxidation processing at 200 V in DI water environments, producing oxides up to 66.6 nm in height and 467.03 nm in width. Oxides produced through high-voltage nano-oxidation in atmospheric environments were 117.29 nm in height and 551.28 nm in width, considerably exceeding the dimensions of those produced in DI water. An increase in the applied bias voltage led to an apparent logarithmic increase in the height of the oxide dots in the range of 200-400 V. The performance of the proposed high-voltage nano-oxidation technique was relatively high with seamless integration between the AFM machine and the metallic probe fabricated in this study. © Wiley Periodicals, Inc.

30 CFR 77.807-3 - Movement of equipment; minimum distance from high-voltage lines.

Code of Federal Regulations, 2010 CFR

2010-07-01

... high-voltage lines. 77.807-3 Section 77.807-3 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... WORK AREAS OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.807-3 Movement of equipment; minimum distance from high-voltage lines. When any part of any equipment operated on the surface of any...

Fast Rise Time and High Voltage Nanosecond Pulses at High Pulse Repetition Frequency

NASA Astrophysics Data System (ADS)

Miller, Kenneth E.; Ziemba, Timothy; Prager, James; Picard, Julian; Hashim, Akel

2015-09-01

Eagle Harbor Technologies (EHT), Inc. is conducting research to decrease the rise time and increase the output voltage of the EHT Nanosecond Pulser product line, which allows for independently, user-adjustable output voltage (0 - 20 kV), pulse width (20 - 500 ns), and pulse repetition frequency (0 - 100 kHz). The goals are to develop higher voltage pulses (50 - 60 kV), decrease the rise time from 20 to below 10 ns, and maintain the high pulse repetition capabilities. These new capabilities have applications to pseudospark generation, corona production, liquid discharges, and nonlinear transmission line driving for microwave production. This work is supported in part by the US Navy SBIR program.

High Voltage Distribution System (HVDS) as a better system compared to Low Voltage Distribution System (LVDS) applied at Medan city power network

NASA Astrophysics Data System (ADS)

Dinzi, R.; Hamonangan, TS; Fahmi, F.

2018-02-01

In the current distribution system, a large-capacity distribution transformer supplies loads to remote locations. The use of 220/380 V network is nowadays less common compared to 20 kV network. This results in losses due to the non-optimal distribution transformer, which neglected the load location, poor consumer profile, and large power losses along the carrier. This paper discusses how high voltage distribution systems (HVDS) can be a better system used in distribution networks than the currently used distribution system (Low Voltage Distribution System, LVDS). The proposed change of the system into the new configuration is done by replacing a large-capacity distribution transformer with some smaller-capacity distribution transformers and installed them in positions that closest to the load. The use of high voltage distribution systems will result in better voltage profiles and fewer power losses. From the non-technical side, the annual savings and payback periods on high voltage distribution systems will also be the advantage.

Ultra-high density diffraction grating

DOEpatents

Padmore, Howard A.; Voronov, Dmytro L.; Cambie, Rossana; Yashchuk, Valeriy V.; Gullikson, Eric M.

2012-12-11

A diffraction grating structure having ultra-high density of grooves comprises an echellette substrate having periodically repeating recessed features, and a multi-layer stack of materials disposed on the echellette substrate. The surface of the diffraction grating is planarized, such that layers of the multi-layer stack form a plurality of lines disposed on the planarized surface of the structure in a periodical fashion, wherein lines having a first property alternate with lines having a dissimilar property on the surface of the substrate. For example, in one embodiment, lines comprising high-Z and low-Z materials alternate on the planarized surface providing a structure that is suitable as a diffraction grating for EUV and soft X-rays. In some embodiments, line density of between about 10,000 lines/mm to about 100,000 lines/mm is provided.

Obtaining high-energy responses of nonlinear piezoelectric energy harvester by voltage impulse perturbations

NASA Astrophysics Data System (ADS)

Lan, Chunbo; Tang, Lihua; Qin, Weiyang

2017-07-01

Nonlinear energy harvesters have attracted wide research attentions to achieve broadband performances in recent years. Nonlinear structures have multiple solutions in certain frequency region that contains high-energy and low-energy orbits. It is effectively the frequency region of capturing a high-energy orbit that determines the broadband performance. Thus, maintaining large-amplitude high-energy-orbit oscillations is highly desired. In this paper, a voltage impulse perturbation approach based on negative resistance is applied to trigger high-energy-orbit responses of piezoelectric nonlinear energy harvesters. First, the mechanism of the voltage impulse perturbation and the implementation of the synthetic negative resistance circuit are discussed in detail. Subsequently, numerical simulation and experiment are conducted and the results demonstrate that the high-energy-orbit oscillations can be triggered by the voltage impulse perturbation method for both monostable and bistable configurations given various scenarios. It is revealed that the perturbation levels required to trigger and maintain high-energy-orbit oscillations are different for various excitation frequencies in the region where multiple solutions exist. The higher gain in voltage output when high-energy-orbit oscillations are captured is accompanied with the demand of a higher voltage impulse perturbation level.

Operational characteristics of a high voltage dense plasma focus

NASA Astrophysics Data System (ADS)

Woodall, D. M.

1985-11-01

A high voltage dense plasma focus powered by a single stage Marx bank was designed, built and operated. The maximum bank parameters are: voltage--120 kV, energy--20 kJ, short circuit current--600kA. The bank impedance is about 200 millohms. The plasma focus center electrode diameter is 1.27 cm. The outer electrode diameter is 10.16 cm. Rundown length is about 10 cm, corresponding to a bank quarter period of about 900 millohms ns. Rundown L is about 50 milliohms. The context of this work is established with a review of previous plasma focus theoretical, experimental and computational work and related topics. Theoretical motivation for high voltage operation is presented. The design, construction and operation of this device are discussed in detail. Results and analysis of measurements obtained are presented. Device operation was investigated primarily at 80 kV (9 kJ), with a gas fill of about 1 torr H2, plus 3-5 percent A. The following diagnostics were used: gun voltage and current measurements; filtered, time resolved x ray PIN measurements of the pinch region; time integrated x ray pinhole photographs of the pinch region; fast frame visible light photographs of the sheath during rundown; and B probe measurements of the current sheath shortly before collapse.

Down to 2 nm Ultra Shallow Junctions : Fabrication by IBS Plasma Immersion Ion Implantation Prototype PULSION registered

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

Torregrosa, Frank; Etienne, Hasnaa; Mathieu, Gilles

Classical beam line implantation is limited in low energies and cannot achieve P+/N junctions requirements for <45nm node. Compared to conventional beam line ion implantation, limited to a minimum of about 200 eV, the efficiency of Plasma Immersion Ion Implantation (PIII) is no more to prove for the realization of Ultra Shallow Junctions (USJ) in semiconductor applications: this technique allows to get ultimate shallow profiles (as implanted) thanks to no lower limitation of energy and offers high dose rate. In the field of the European consortium NANOCMOS, Ultra Shallow Junctions implanted on a semi-industrial PIII prototype (PULSION registered ) designedmore » by the French company IBS, have been studied. Ultra shallow junctions implanted with BF3 at acceleration voltages down to 20V were realized. Contamination level, homogeneity and depth profile are studied. The SIMS profiles obtained show the capability to make ultra shallow profiles (as implanted) down to 2nm.« less

Relating voltage and thermal safety in Li-ion battery cathodes: a high-throughput computational study.

PubMed

Jain, Anubhav; Hautier, Geoffroy; Ong, Shyue Ping; Dacek, Stephen; Ceder, Gerbrand

2015-02-28

High voltage and high thermal safety are desirable characteristics of cathode materials, but difficult to achieve simultaneously. This work uses high-throughput density functional theory computations to evaluate the link between voltage and safety (as estimated by thermodynamic O2 release temperatures) for over 1400 cathode materials. Our study indicates that a strong inverse relationship exists between voltage and safety: just over half the variance in O2 release temperature can be explained by voltage alone. We examine the effect of polyanion group, redox couple, and ratio of oxygen to counter-cation on both voltage and safety. As expected, our data demonstrates that polyanion groups improve safety when comparing compounds with similar voltages. However, a counterintuitive result of our study is that polyanion groups produce either no benefit or reduce safety when comparing compounds with the same redox couple. Using our data set, we tabulate voltages and oxidation potentials for over 105 combinations of redox couple/anion, which can be used towards the design and rationalization of new cathode materials. Overall, only a few compounds in our study, representing limited redox couple/polyanion combinations, exhibit both high voltage and high safety. We discuss these compounds in more detail as well as the opportunities for designing safe, high-voltage cathodes.

2 kV slanted tri-gate GaN-on-Si Schottky barrier diodes with ultra-low leakage current

NASA Astrophysics Data System (ADS)

Ma, Jun; Matioli, Elison

2018-01-01

This letter reports lateral GaN-on-Si power Schottky barrier diodes (SBDs) with unprecedented voltage-blocking performance by integrating 3-dimensionally a hybrid of tri-anode and slanted tri-gate architectures in their anode. The hybrid tri-anode pins the voltage drop at the Schottky junction (VSCH), despite a large applied reverse bias, fixing the reverse leakage current (IR) of the SBD. Such architecture led to an ultra-low IR of 51 ± 5.9 nA/mm at -1000 V, in addition to a small turn-on voltage (VON) of 0.61 ± 0.03 V. The slanted tri-gate effectively distributes the electric field in OFF state, leading to a remarkably high breakdown voltage (VBR) of -2000 V at 1 μA/mm, constituting a significant breakthrough from existing technologies. The approach pursued in this work reduces the IR and increases the VBR without sacrificing the VON, which provides a technology for high-voltage SBDs, and unveils the unique advantage of tri-gates for advanced power applications.

Current collection by high voltage anodes in near ionospheric conditions

NASA Technical Reports Server (NTRS)

Antoniades, John A.; Greaves, Rod G.; Boyd, D. A.; Ellis, R.

1990-01-01

The authors experimentally identified three distinct regimes with large differences in current collection in the presence of neutrals and weak magnetic fields. In magnetic field/anode voltage space the three regions are separated by very sharp transition boundaries. The authors performed a series of laboratory experiments to study the dependence of the region boundaries on several parameters, such as the ambient neutral density, plasma density, magnetic field strength, applied anode voltage, voltage pulsewidth, chamber material, chamber size and anode radius. The three observed regimes are: classical magnetic field limited collection; stable medium current toroidal discharge; and large scale, high current space glow discharge. There is as much as several orders of magnitude of difference in the amount of collected current upon any boundary crossing, particularly if one enters the space glow regime. They measured some of the properties of the plasma generated by the breakdown that is present in regimes II and III in the vicinity of the anode including the sheath modified electrostatic potential, I-V characteristics at high voltage as well as the local plasma density.

Link and Network Layers Design for Ultra-High-Speed Terahertz-Band Communications Networks

DTIC Science & Technology

2017-01-01

throughput, and identify the optimal parameter values for their design (Sec. 6.2.3). Moreover, we validate and test the scheme with experimental data obtained...LINK AND NETWORK LAYERS DESIGN FOR ULTRA-HIGH- SPEED TERAHERTZ-BAND COMMUNICATIONS NETWORKS STATE UNIVERSITY OF NEW YORK (SUNY) AT BUFFALO JANUARY...TYPE FINAL TECHNICAL REPORT 3. DATES COVERED (From - To) FEB 2015 – SEP 2016 4. TITLE AND SUBTITLE LINK AND NETWORK LAYERS DESIGN FOR ULTRA-HIGH

A high voltage ratio and low ripple interleaved DC-DC converter for fuel cell applications.

PubMed

Chang, Long-Yi; Chao, Kuei-Hsiang; Chang, Tsang-Chih

2012-01-01

This paper proposes a high voltage ratio and low ripple interleaved boost DC-DC converter, which can be used to reduce the output voltage ripple. This converter transfers the low DC voltage of fuel cell to high DC voltage in DC link. The structure of the converter is parallel with two voltage-doubler boost converters by interleaving their output voltages to reduce the voltage ripple ratio. Besides, it can lower the current stress for the switches and inductors in the system. First, the PSIM software was used to establish a proton exchange membrane fuel cell and a converter circuit model. The simulated and measured results of the fuel cell output characteristic curve are made to verify the correctness of the established simulation model. In addition, some experimental results are made to validate the effectiveness in improving output voltage ripple of the proposed high voltage ratio interleaved boost DC-DC converters.

A high-precision voltage source for EIT

PubMed Central

Saulnier, Gary J; Liu, Ning; Ross, Alexander S

2006-01-01

Electrical impedance tomography (EIT) utilizes electrodes placed on the surface of a body to determine the complex conductivity distribution within the body. EIT can be performed by applying currents through the electrodes and measuring the electrode voltages or by applying electrode voltages and measuring the currents. Techniques have also been developed for applying the desired currents using voltage sources. This paper describes a voltage source for use in applied-voltage EIT that includes the capability of measuring both the applied voltage and applied current. A calibration circuit and calibration algorithm are described which enables all voltage sources in an EIT system to be calibrated to a common standard. The calibration minimizes the impact of stray shunt impedance, passive component variability and active component non-ideality. Simulation data obtained using PSpice are used to demonstrate the effectiveness of the circuits and calibration algorithm. PMID:16636413

Adaptive sensor-based ultra-high accuracy solar concentrator tracker

NASA Astrophysics Data System (ADS)

Brinkley, Jordyn; Hassanzadeh, Ali

2017-09-01

Conventional solar trackers use information of the sun's position, either by direct sensing or by GPS. Our method uses the shading of the receiver. This, coupled with nonimaging optics design allows us to achieve ultra-high concentration. Incorporating a sensor based shadow tracking method with a two stage concentration solar hybrid parabolic trough allows the system to maintain high concentration with acute accuracy.

Design, conditioning, and performance of a high voltage, high brightness dc photoelectron gun with variable gap

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

Maxson, Jared; Bazarov, Ivan; Dunham, Bruce

2014-09-15

A new high voltage photoemission gun has been constructed at Cornell University which features a segmented insulator and a movable anode, allowing the cathode-anode gap to be adjusted. In this work, we describe the gun's overall mechanical and high voltage design, the surface preparation of components, as well as the clean construction methods. We present high voltage conditioning data using a 50 mm cathode-anode gap, in which the conditioning voltage exceeds 500 kV, as well as at smaller gaps. Finally, we present simulated emittance results obtained from a genetic optimization scheme using voltage values based on the conditioning data. Thesemore » results indicate that for charges up to 100 pC, a 30 mm gap at 400 kV has equal or smaller 100% emittance than a 50 mm gap at 450 kV, and also a smaller core emittance, when placed as the source for the Cornell energy recovery linac photoinjector with bunch length constrained to be <3 ps rms. For 100 pC up to 0.5 nC charges, the 50 mm gap has larger core emittance than the 30 mm gap, but conversely smaller 100% emittance.« less

High Voltage TAL Erosion Characterization

NASA Technical Reports Server (NTRS)

Jacobson, David T.

2003-01-01

Extended operation of a D-80 anode layer thruster at high voltage was investigated. The thruster was operated for 1200 hours at 700 Volts and 4 Amperes. Laser profilometry was employed to quantify the erosion of the thruster's graphite guard rings and electrodes at 0, 300, 600, 900, and 1200 hours. Thruster performance and electrical characteristics were monitored over the duration of the investigation. The guard rings exhibited asymmetric erosion that was greatest in the region of the cathode. Erosion of the guard rings exposed the magnet poles between 600 to 900 hours of operation.

High-efficiency water-loaded microwave antenna in ultra-high-frequency band

NASA Astrophysics Data System (ADS)

Gong, Zilun; Bartone, Chris; Yang, Fuyi; Yao, Jie

2018-03-01

High-index dielectrics are widely used in microwave antennas to control the radiation characteristics. Liquid water, with a high dielectric index at microwave frequency, is an interesting material to achieving tunable functionalities. Here, we demonstrate a water-loaded microwave antenna system that has high loss-tolerance and wideband tunability enabled by fluidity. Our simulation and experimental results show that the resonance frequency can be effectively tuned by the size of loading water. Furthermore, the antenna systems with water loading can achieve high radiation efficiency (>90%) in the ultra-high-frequency (0.3-3 GHz) band. This work brings about opportunities in realistic tunable microwave antenna designs enabled by liquid.

High-performance Ge p-i-n photodetector on Si substrate

NASA Astrophysics Data System (ADS)

Chen, Li-qun; Huang, Xiang-ying; Li, Min; Huang, Yan-hua; Wang, Yue-yun; Yan, Guang-ming; Li, Cheng

2015-05-01

High-performance and tensile-strained germanium (Ge) p-i-n photodetector is demonstrated on Si substrate. The epitaxial Ge layers were prepared in an ultrahigh vacuum chemical vapor deposition (UHV-CVD) system using low temperature Ge buffer technique. The devices were fabricated by in situ doping and using Si as passivation layer between Ge and metal, which can improve the ohmic contact and realize the high doping. The results show that the dark current of the photodetector with diameter of 24 μm is about 2.5×10-7 μA at the bias voltage of -1 V, and the optical responsivity is 0.1 A/W at wavelength of 1.55 μm. The 3 dB bandwidth (BW) of 4 GHz is obtained for the photodetector with diameter of 24 μm at reverse bias voltage of 1 V. The long diffusion time of minority carrier in n-type Ge and the large contact resistance in metal/Ge contacts both affect the performance of Ge photodetectors.

Ultrastable Natural Ester-Based Nanofluids for High Voltage Insulation Applications.

PubMed

Peppas, Georgios D; Bakandritsos, Aristides; Charalampakos, Vasilis P; Pyrgioti, Eleftheria C; Tucek, Jiri; Zboril, Radek; Gonos, Ioannis F

2016-09-28

Nanofluids for high voltage insulation systems have emerged as a potential substitute for liquid dielectrics in industrial applications. Nevertheless, the sedimentation of nanoparticles has been so far a serious barrier for their wide and effective exploitation. The present work reports on the development and in-depth characterization of colloidally ultrastable natural ester oil insulation systems containing iron oxide nanocrystals which lift the problem of sedimentation and phase separation. Compared to state-of-the-art systems, the final product is endowed with increased dielectric strength, faster thermal response, lower dielectric losses (decreased dissipation factor: tan δ), and very high endurance during discharge stressing. The developed nanofluid was studied and compared with a similar system containing commercial iron oxide nanoparticles, the latter demonstrating extensive sedimentation. Herein, the dielectric properties of the nanofluids are analyzed at various concentrations by means of breakdown voltage and dissipation factor measurements. The characterization techniques unequivocally demonstrate the high performance reliability of the reported nanofluid, which constitutes a significant breakthrough in the field of high voltage insulation technologies.

30 CFR 56.12071 - Movement or operation of equipment near high-voltage power lines.

Code of Federal Regulations, 2010 CFR

2010-07-01

...-voltage power lines. 56.12071 Section 56.12071 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... NONMETAL MINES Electricity § 56.12071 Movement or operation of equipment near high-voltage power lines. When equipment must be moved or operated near energized high-voltage powerlines (other than trolley...

High throughput ion-channel pharmacology: planar-array-based voltage clamp.

PubMed

Kiss, Laszlo; Bennett, Paul B; Uebele, Victor N; Koblan, Kenneth S; Kane, Stefanie A; Neagle, Brad; Schroeder, Kirk

2003-02-01

Technological advances often drive major breakthroughs in biology. Examples include PCR, automated DNA sequencing, confocal/single photon microscopy, AFM, and voltage/patch-clamp methods. The patch-clamp method, first described nearly 30 years ago, was a major technical achievement that permitted voltage-clamp analysis (membrane potential control) of ion channels in most cells and revealed a role for channels in unimagined areas. Because of the high information content, voltage clamp is the best way to study ion-channel function; however, throughput is too low for drug screening. Here we describe a novel breakthrough planar-array-based HT patch-clamp technology developed by Essen Instruments capable of voltage-clamping thousands of cells per day. This technology provides greater than two orders of magnitude increase in throughput compared with the traditional voltage-clamp techniques. We have applied this method to study the hERG K(+) channel and to determine the pharmacological profile of QT prolonging drugs.

A High Voltage Ratio and Low Ripple Interleaved DC-DC Converter for Fuel Cell Applications

PubMed Central

Chang, Long-Yi; Chao, Kuei-Hsiang; Chang, Tsang-Chih

2012-01-01

This paper proposes a high voltage ratio and low ripple interleaved boost DC-DC converter, which can be used to reduce the output voltage ripple. This converter transfers the low DC voltage of fuel cell to high DC voltage in DC link. The structure of the converter is parallel with two voltage-doubler boost converters by interleaving their output voltages to reduce the voltage ripple ratio. Besides, it can lower the current stress for the switches and inductors in the system. First, the PSIM software was used to establish a proton exchange membrane fuel cell and a converter circuit model. The simulated and measured results of the fuel cell output characteristic curve are made to verify the correctness of the established simulation model. In addition, some experimental results are made to validate the effectiveness in improving output voltage ripple of the proposed high voltage ratio interleaved boost DC-DC converters. PMID:23365536

Operational Characteristics of a High Voltage Dense Plasma Focus.

DTIC Science & Technology

1985-11-01

A high voltage dense plasma focus powered by a single-stage Marx bank was designed, built and operated. The maximum bank parameters are: voltage--120...kV, energy--20 kJ, short-circuit current--600kA. The bank impedance is about 200 millohms. The plasma focus center electrode diameter is 1.27 cm. The...about 50 milliohms. The context of this work is established with a review of previous plasma focus theoretical, experimental and computational work and

A compact ultra-clean system for deploying radioactive sources inside the KamLAND detector

NASA Astrophysics Data System (ADS)

Banks, T. I.; Freedman, S. J.; Wallig, J.; Ybarrolaza, N.; Gando, A.; Gando, Y.; Ikeda, H.; Inoue, K.; Kishimoto, Y.; Koga, M.; Mitsui, T.; Nakamura, K.; Shimizu, I.; Shirai, J.; Suzuki, A.; Takemoto, Y.; Tamae, K.; Ueshima, K.; Watanabe, H.; Xu, B. D.; Yoshida, H.; Yoshida, S.; Kozlov, A.; Grant, C.; Keefer, G.; Piepke, A.; Bloxham, T.; Fujikawa, B. K.; Han, K.; Ichimura, K.; Murayama, H.; O`Donnell, T.; Steiner, H. M.; Winslow, L. A.; Dwyer, D. A.; McKeown, R. D.; Zhang, C.; Berger, B. E.; Lane, C. E.; Maricic, J.; Miletic, T.; Batygov, M.; Learned, J. G.; Matsuno, S.; Sakai, M.; Horton-Smith, G. A.; Downum, K. E.; Gratta, G.; Efremenko, Y.; Perevozchikov, O.; Karwowski, H. J.; Markoff, D. M.; Tornow, W.; Heeger, K. M.; Detwiler, J. A.; Enomoto, S.; Decowski, M. P.

2015-01-01

We describe a compact, ultra-clean device used to deploy radioactive sources along the vertical axis of the KamLAND liquid-scintillator neutrino detector for purposes of calibration. The device worked by paying out and reeling in precise lengths of a hanging, small-gauge wire rope (cable); an assortment of interchangeable radioactive sources could be attached to a weight at the end of the cable. All components exposed to the radiopure liquid scintillator were made of chemically compatible UHV-cleaned materials, primarily stainless steel, in order to avoid contaminating or degrading the scintillator. To prevent radon intrusion, the apparatus was enclosed in a hermetically sealed housing inside a glove box, and both volumes were regularly flushed with purified nitrogen gas. An infrared camera attached to the side of the housing permitted real-time visual monitoring of the cable's motion, and the system was controlled via a graphical user interface.

Ultra-compact high-performance MCT MWIR engine

NASA Astrophysics Data System (ADS)

Lutz, H.; Breiter, R.; Eich, D.; Figgemeier, H.; Oelmaier, R.; Rutzinger, S.; Schenk, H.; Wendler, J.

2017-02-01

Size, weight and power (SWaP) reduction is highly desired by applications such as sights for the dismounted soldier or small gimbals for UAVs. But why have high performance and small size of IR systems inevitably exclude each other? Namely, recent development progress in the fields of miniature cryocoolers, short dewars and high operating temperature (HOT) FPAs combined with pitch size reduction opens the door for very compact MWIR-modules while keeping high electro-optical performance. Now, AIM has realized first prototypes of an ultra-compact high-performance MWIR engine in a total volume of only 18cl (60mm length x 60mm height x 50mm width). Impressive SWaP characteristics are completed by a total weight below 400g and a power consumption < 4W in basic imaging mode. The engine consists of a XGA-format (1024x768) MCT detector array with 10μm pitch and a low power consuming ROIC. It is cooled down to a typical operating temperature of 160K by the miniature linear cryocooler SX020. The dewar uses a short coldfinger and is designed to reduce the heat load as much as possible. The cooler drive electronics is implemented in the CCE layout in order to reduce the required space of the printed boards and to save power. Uncorrected 14bit video data is provided via Camera Link. Optionally, a small image processing board can be stacked on top of the CCE to gain access to basic functions such as BPR, 2- point NUC and dynamic reduction. This paper will present the design, functionalities and performance data of the ultra-compact MCT MWIR engine operated at HOT.

High-voltage plasma interactions calculations using NASCAP/LEO

NASA Technical Reports Server (NTRS)

Mandell, M. J.; Katz, I.

1990-01-01

This paper reviews four previous simulations (two laboratory and two space-flight) of interactions of a high-voltage spacecraft with a plasma under low-earth orbit conditions, performed using a three-dimensional computer code NASCAP/LEO. Results show that NASCAP/LEO can perform meaningful simulations of high-voltage plasma interactions taking into account three-dimensional effects of geometry, spacecraft motion, and magnetic field. Two new calculations are presented: (1) for current collection by 1-mm pinholes in wires (showing that a pinhole in a wire can collect far more current than a similar pinhole in a flat plate); and (2) current collection by Charge-2 mother vehicle launched in December 1985. It is shown that the Charge-2 calculations predicted successfully ion collection at negative bias, the floating potential of a probe outside or inside the sheath under negative bias conditions, and magnetically limited electron collection under electron beam operation at high altitude.

Radiation damage in high voltage silicon solar cells

NASA Technical Reports Server (NTRS)

Weinberg, I.; Brandhorst, H., Jr.; Swartz, C. K.; Weizer, V. G.

1980-01-01

Three high open-circuit voltage cell designs based on 0.1 ohm-cm p-type silicon were irradiated with 1 MeV electrons and their performance determined to fluences as high as 10 to the 15th power/sq cm. Of the three cell designs, radiation induced degradation was greatest in the high-low emitter (HLE cell). The diffused and ion implanted cells degraded approximately equally but less than the HLE cell. Degradation was greatest in an HLE cell exposed to X-rays before electron irradiation. The cell regions controlling both short-circuit current and open-circuit voltage degradation were defined in all three cell types. An increase in front surface recombination velocity accompanied time dependent degradation of an HLE cell after X-irradiation. It was speculated that this was indirectly due to a decrease in positive charge at the silicon-oxide interface. Modifications aimed at reducing radiation induced degradation are proposed for all three cell types.

Bond Behavior of Reinforcing Steel in Ultra-High Performance Concrete

DOT National Transportation Integrated Search

2014-11-01

Ultra-high performance concrete (UHPC) has garnered interest from the highway infrastructure community for its greatly enhanced mechanical and durability properties. The objective of this research is to extensively evaluate the factors that affect bo...

30 CFR 77.807-2 - Booms and masts; minimum distance from high-voltage lines.

Code of Federal Regulations, 2010 CFR

2010-07-01

...-voltage lines. 77.807-2 Section 77.807-2 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... WORK AREAS OF UNDERGROUND COAL MINES Surface High-Voltage Distribution § 77.807-2 Booms and masts; minimum distance from high-voltage lines. The booms and masts of equipment operated on the surface of any...

Broadband linear high-voltage amplifier for radio frequency ion traps.

PubMed

Kuhlicke, Alexander; Palis, Klaus; Benson, Oliver

2014-11-01

We developed a linear high-voltage amplifier for small capacitive loads consisting of a high-voltage power supply and a transistor amplifier. With this cost-effective circuit including only standard parts sinusoidal signals with a few volts can be amplified to 1.7 kVpp over a usable frequency range at large-signal response spanning four orders of magnitude from 20 Hz to 100 kHz under a load of 10 pF. For smaller output voltages the maximum frequency shifts up to megahertz. We test different capacitive loads to probe the influence on the performance. The presented amplifier is sustained short-circuit proof on the output side, which is a significant advantage over other amplifier concepts. The amplifier can be used to drive radio frequency ion traps for single charged nano- and microparticles, which will be presented in brief.

SSP Technology Investigation of a High-Voltage DC-DC Converter

NASA Technical Reports Server (NTRS)

Pappas, J. A.; Grady, W. M.; George, Patrick J. (Technical Monitor)

2002-01-01

The goal of this project was to establish the feasibility of a high-voltage DC-DC converter based on a rod-array triggered vacuum switch (RATVS) for the Space Solar Power system. The RATVS has many advantages over silicon and silicon-carbide devices. The RATVS is attractive for this application because it is a high-voltage device that has already been demonstrated at currents in excess of the requirement for an SSP device and at much higher per-device voltages than existing or near-term solid state switching devices. The RATVS packs a much higher specific power rating than any solid-state device and it is likely to be more tolerant of its surroundings in space. In addition, pursuit of an RATVS-based system would provide NASA with a nearer-term and less expensive power converter option for the SSP.

Waste heat recovery with ultra high-speed turbomachinery

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

Vakkilainen, E.; Larjola, J.; Lindgren, O.

1984-08-01

A new ORC heat recovery system which converts waste heat to electricity has been developed in Lappeenranta University of Technology with support from Department of Energy in Finnish Ministry of Trade and Industry. Use of ultra high-speed turbomachinery (10 000 rpm - 200 000 rpm) promises lower unit costs, higher efficiencies and fast amortization rate, 2,4 - 3,0 years.

[Reparative Osteogenesis and Angiogenesis in Low Intensity Electromagnetic Radiation of Ultra-High Frequency].

PubMed

Iryanov, Y M; Kiryanov, N A

2015-01-01

Non-drug correction of reparative bone tissue regeneration in different pathological states - one of the most actual problems of modern medicine. Our aim was to conduct morphological analysis of the influence of electromagnetic radiation of ultra-high frequency and low intensity on reparative osteogenesis and angiogenesis in fracture treatment under transosseous osteosynthesis. A controlled nonrandomized study was carried out. In the experiment conducted on rats we modeled tibial fracture with reposition and fixation of the bone fragments both in control and experimental groups. In the animals of the experimental group the fracture zone was exposed to low intensity electromagnetic radiation of ultra-high frequency. Exposure simulation was performed in the control group. The operated bones were examined using radiography, light and electronic microscopy, X-ray electronic probe microanalysis. It has been established that electromagnetic radiation of ultra-high frequency sessions in fracture treatment stimulate secretory activity and degranulation of mast cells, produce microcirculatory bed vascular permeability increase, endotheliocyte migration phenotype expression, provide endovascular endothelial outgrowth formation, activate reparative osteogenesis and angiogenesis while fracture reparation becomes the one of the primary type. The full periosteal, intermediary and intraosteal bone union was defined in 28 days. Among the therapeutic benefits of electromagnetic radiation of ultra-high frequency in fracture treatment we can detect mast cell secretorv activity stimulation and endovascular anziozenesis activation.

Cermet insert high voltage holdoff improvement for ceramic/metal vacuum devices

DOEpatents

Ierna, W.F.

1986-03-11

An improved metal-to-ceramic seal is provided wherein the ceramic body of the seal contains an integral region of cermet material in electrical contact with the metallic member, e.g., an electrode, of the seal. The seal is useful in high voltage vacuum devices, e.g., vacuum switches, and increases the high-voltage holdoff capabilities of such devices. A method of fabricating such seals is also provided.

Development of Non-Proprietary Ultra-High Performance Concrete : Final Report