National Library of Energy BETA

Sample records for dc fl ga

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

    SciTech Connect (OSTI)

    M.L. Stutzman; P. Adderley; J. Brittian; J. Clark; J. Grames; J. Hansknecht; G.R. Myneni; M. Poelker

    2007-05-01

    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 part 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.

  2. DC characteristics of OMVPE-grown N-p-n InGaP/InGaAsN DHBTs

    SciTech Connect (OSTI)

    Li, N.Y.; Chang, P.C.; Baca, A.G.; Xie, X.M.; Sharps, P.R.; Hou, H.Q.

    2000-01-04

    The authors demonstrate, for the first time, a functional N-p-n heterojunction bipolar transistor using a novel material, InGaAsN, with a bandgap energy of 1.2eV as the p-type base layer. A 300{angstrom}-thick In{sub x}Ga{sub 1-x}As graded layer was introduced to reduce the conduction band offset at the p-type InGaAsN base and n-type GaAs collector junction. For an emitter size of 500 {mu}m{sup 2}, a peak current gain of 5.3 has been achieved.

  3. Sr. Engineer, Water Resources Univ of FL-SW FL Research & Education Center Immokalee, FL

    E-Print Network [OSTI]

    Hill, Jeffrey E.

    Sr. Engineer, Water Resources Univ of FL-SW FL Research & Education Center ­ Immokalee, FL Technical position for research, extension, and teaching of water resources (quantity and quality and implementing construction plans for water resources projects, carrying out field and laboratory experiments

  4. Monolithically Peltier-cooled vertical-cavity surface-emitting lasers Paul FL Berger, Niloy K. Dutta, Kent D. Choquette, Ghulam Hasnain, and Naresh Chand

    E-Print Network [OSTI]

    Monolithically Peltier-cooled vertical-cavity surface-emitting lasers Paul FL Berger, Niloy K. The thermoelectric element is the n + -GaAs substrate based on the Peltier effect. A variation of active region contact on the n + -GaAs substrate. The thermoelectric (Peltier) ef- fect of the n f -GaAs substrate can

  5. Census Snapshot: Washington, DC

    E-Print Network [OSTI]

    Romero, Adam P.; Baumle, Amanda K; Badgett, M.V. Lee; Gates, Gary J

    2007-01-01

    INSTITUTE CENSUS SNAPSHOT | WASHINGTON, DC. | DECEMBER 2007WASHINGTON, D.C. Adam P. Romero, Public Policy Fellow AmandaINSTITUTE CENSUS SNAPSHOT | WASHINGTON, DC. | DECEMBER 2007

  6. Mesoscopic photovoltaic effect in GaAs/Ga1-xAlxAs Aharonov-Bohm rings L. Angers, A. Chepelianskii, R. Deblock, B. Reulet, and H. Bouchiat

    E-Print Network [OSTI]

    Shepelyansky, Dima

    Mesoscopic photovoltaic effect in GaAs/Ga1-xAlxAs Aharonov-Bohm rings L. Angers, A. Chepelianskii specific dc voltage. We have investigated this photovoltaic PV effect on GaAs/Ga1-xAlxAs Aharonov is generally done by measuring the dc induced signal sometimes called photovoltaic effect which has also given

  7. Record 1, Side B (FL1088)

    E-Print Network [OSTI]

    Whitehorn, John

    stream_source_info 1 FL 1088 B_whitehorn.pdf.txt stream_content_type text/plain stream_size 1 Content-Encoding ISO-8859-1 stream_name 1 FL 1088 B_whitehorn.pdf.txt Content-Type text/plain; charset=ISO-8859-1 ...

  8. Record 2, Side B (FL1144)

    E-Print Network [OSTI]

    Whitehorn, John

    stream_source_info 2 FL 1144 B_whitehorn.pdf.txt stream_content_type text/plain stream_size 1 Content-Encoding ISO-8859-1 stream_name 2 FL 1144 B_whitehorn.pdf.txt Content-Type text/plain; charset=ISO-8859-1 ...

  9. Radio frequency dc-dc power conversion

    E-Print Network [OSTI]

    Rivas, Juan, 1976-

    2007-01-01

    THIS THESIS addresses the development of system architectures and circuit topologies for dc-dc power conversion at very high frequencies. The systems architectures that are developed are structured to overcome limitations ...

  10. Building Scale DC Microgrids

    E-Print Network [OSTI]

    Marnay, Chris

    2013-01-01

    however, DC was less amenable to transmission over longtransmission 32 km to Buffalo, even though the loads at that time were entirely DC.

  11. Building Scale DC Microgrids

    E-Print Network [OSTI]

    Marnay, Chris

    2014-01-01

    ABORATORY Building Scale DC Microgrids Chris Marnay, Stevenemployer. Building Scale DC Microgrids Chris Marnay, IEEEgenerally known as microgrids (or µgrids). The dominance of

  12. September 2011 Dear FL Beef Cattle Producers,

    E-Print Network [OSTI]

    Hill, Jeffrey E.

    September 2011 Dear FL Beef Cattle Producers, I am the veterinary entomologist for UF-IFAS and am beef cattle producers who have extensively used the Avenger insecticide ear tag on their cattle on beef cattle. However, the horn fly is expected to develop resistance to this chemical as it has most

  13. DC source assemblies

    DOE Patents [OSTI]

    Campbell, Jeremy B; Newson, Steve

    2013-02-26

    Embodiments of DC source assemblies of power inverter systems of the type suitable for deployment in a vehicle having an electrically grounded chassis are provided. An embodiment of a DC source assembly comprises a housing, a DC source disposed within the housing, a first terminal, and a second terminal. The DC source also comprises a first capacitor having a first electrode electrically coupled to the housing, and a second electrode electrically coupled to the first terminal. The DC source assembly further comprises a second capacitor having a first electrode electrically coupled to the housing, and a second electrode electrically coupled to the second terminal.

  14. Inverse spin Hall effect in Pt/(Ga,Mn)As

    SciTech Connect (OSTI)

    Nakayama, H.; Chen, L.; Chang, H. W.; Ohno, H.; Matsukura, F.

    2015-06-01

    We investigate dc voltages under ferromagnetic resonance in a Pt/(Ga,Mn)As bilayer structure. A part of the observed dc voltage is shown to originate from the inverse spin Hall effect. The sign of the inverse spin Hall voltage is the same as that in Py/Pt bilayer structure, even though the stacking order of ferromagnetic and nonmagnetic layers is opposite to each other. The spin mixing conductance at the Pt/(Ga,Mn)As interface is determined to be of the order of 10{sup 19?}m{sup ?2}, which is about ten times greater than that of (Ga,Mn)As/p-GaAs.

  15. Building Scale DC Microgrids

    E-Print Network [OSTI]

    Marnay, Chris

    2014-01-01

    involves DC directly, e.g. fuel cells, fuels, but electricthe likely emergence of fuel cells and required batteriesphotovoltaic cells, fuel cells, power quality, converters,

  16. Building Scale DC Microgrids

    E-Print Network [OSTI]

    Marnay, Chris

    2013-01-01

    the likely emergence of fuel cells and required batteriesphotovoltaic cells, fuel cells, power quality, converters,DC) generation, e.g. fuel cells (FCs), from combustion

  17. Building Scale DC Microgrids

    E-Print Network [OSTI]

    Marnay, Chris

    2013-01-01

    resources, a 10 kW vertical axis wind turbine, and Fig. 4AC-grid Fig. 3. Vertical axis wind turbine in the AIT DC µ

  18. Building Scale DC Microgrids

    E-Print Network [OSTI]

    Marnay, Chris

    2014-01-01

    resources, a 10 kW vertical axis wind turbine, and Fig. 4the µgrid Fig. 3. Vertical axis wind turbine in the AIT DC µ

  19. Vision FL LLC | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page| Open Energy Information Serbia-EnhancingEt Al.,Turin,Village of Wellington,FL LLC Jump to: navigation, search Name:

  20. US SoAtl FL Site Consumption

    Gasoline and Diesel Fuel Update (EIA)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustments (Billion Cubic Feet) Wyoming963 1.969 1.979Coal Consumers inYear JanSales Type: Sales120NE MA SiteFL

  1. Multilevel DC link inverter

    DOE Patents [OSTI]

    Su, Gui-Jia

    2003-06-10

    A multilevel DC link inverter and method for improving torque response and current regulation in permanent magnet motors and switched reluctance motors having a low inductance includes a plurality of voltage controlled cells connected in series for applying a resulting dc voltage comprised of one or more incremental dc voltages. The cells are provided with switches for increasing the resulting applied dc voltage as speed and back EMF increase, while limiting the voltage that is applied to the commutation switches to perform PWM or dc voltage stepping functions, so as to limit current ripple in the stator windings below an acceptable level, typically 5%. Several embodiments are disclosed including inverters using IGBT's, inverters using thyristors. All of the inverters are operable in both motoring and regenerating modes.

  2. TRIBAL ISSUES TOPIC GROUP MEETING SUMMARY JACKSONVILLE, FL

    Office of Environmental Management (EM)

    JACKSONVILLE, FL JANUARY 20, 1999 Mr. Kevin Blackwell (USDOTFRA) updated the group on the status of the DOT response to DOE's inquiry about the tribal right to inspect rail...

  3. DC attenuation meter

    DOE Patents [OSTI]

    Hargrove, Douglas L.

    2004-09-14

    A portable, hand-held meter used to measure direct current (DC) attenuation in low impedance electrical signal cables and signal attenuators. A DC voltage is applied to the signal input of the cable and feedback to the control circuit through the signal cable and attenuators. The control circuit adjusts the applied voltage to the cable until the feedback voltage equals the reference voltage. The "units" of applied voltage required at the cable input is the system attenuation value of the cable and attenuators, which makes this meter unique. The meter may be used to calibrate data signal cables, attenuators, and cable-attenuator assemblies.

  4. DC arc weld starter

    DOE Patents [OSTI]

    Campiotti, Richard H. (Tracy, CA); Hopwood, James E. (Oakley, CA)

    1990-01-01

    A system for starting an arc for welding uses three DC power supplies, a high voltage supply for initiating the arc, an intermediate voltage supply for sustaining the arc, and a low voltage welding supply directly connected across the gap after the high voltage supply is disconnected.

  5. US Hydro 2011 Tampa, FL April 2528, 2011 1 On the Horizon

    E-Print Network [OSTI]

    New Hampshire, University of

    US Hydro 2011 Tampa, FL April 2528, 2011 1 On the Horizon: Better Bottom Detection for areas the eelgrass canopy and seafloor. #12;US Hydro 2011 Tampa, FL April 2528, 2011 2 Figure 1: Bottom detections

  6. Auxiliary resonant DC tank converter

    DOE Patents [OSTI]

    Peng, Fang Z. (Knoxville, TN)

    2000-01-01

    An auxiliary resonant dc tank (ARDCT) converter is provided for achieving soft-switching in a power converter. An ARDCT circuit is coupled directly across a dc bus to the inverter to generate a resonant dc bus voltage, including upper and lower resonant capacitors connected in series as a resonant leg, first and second dc tank capacitors connected in series as a tank leg, and an auxiliary resonant circuit comprising a series combination of a resonant inductor and a pair of auxiliary switching devices. The ARDCT circuit further includes first clamping means for holding the resonant dc bus voltage to the dc tank voltage of the tank leg, and second clamping means for clamping the resonant dc bus voltage to zero during a resonant period. The ARDCT circuit resonantly brings the dc bus voltage to zero in order to provide a zero-voltage switching opportunity for the inverter, then quickly rebounds the dc bus voltage back to the dc tank voltage after the inverter changes state. The auxiliary switching devices are turned on and off under zero-current conditions. The ARDCT circuit only absorbs ripples of the inverter dc bus current, thus having less current stress. In addition, since the ARDCT circuit is coupled in parallel with the dc power supply and the inverter for merely assisting soft-switching of the inverter without participating in real dc power transmission and power conversion, malfunction and failure of the tank circuit will not affect the functional operation of the inverter; thus a highly reliable converter system is expected.

  7. Graphic: FL Dept. of Environmental Protection Please pass the Salt!!

    E-Print Network [OSTI]

    Graphic: FL Dept. of Environmental Protection Please pass the Salt!! Mangroves are a very unique protruding from the tree trunk and branches. These prop roots are special because they exclude salt from actually absorb saltwater through their roots, but have specially designed leaves with salt glands

  8. SALT-flSH INPUSTRIES FISHERY LEAFLET 240

    E-Print Network [OSTI]

    SALT-flSH INPUSTRIES FISHERY LEAFLET 240 FISH AND WILDLIFE SERVICE UNITED STATES DEPARTMENT, Albert M. Day, Director #12;THE VENEZUKLAN SALT-FISH INDUSTRIES CONTE^fTS Part II Potential Productive and Craft 29 Development of Unused or Underutilized Species 29 Development of New Areas 35 Salt 35 Studies

  9. Walton County Coastal Storm Damage Reduction Project Walton County, FL

    E-Print Network [OSTI]

    US Army Corps of Engineers

    to reduce coastal storm damages by constructing berms and dunes along 18.8 miles of Walton County shoreline;vegetation and replacement of dune walkover structures as required. Material for the berm and duneWalton County Coastal Storm Damage Reduction Project Walton County, FL 13 December 2012 ABSTRACT

  10. Improved DC Gun Insulator

    SciTech Connect (OSTI)

    M.L. Neubauer, K.B. Beard, R. Sah, C. Hernandez-Garcia, G. Neil

    2009-05-01

    Many user facilities such as synchrotron light sources and free electron lasers require accelerating structures that support electric fields of 10-100 MV/m, especially at the start of the accelerator chain where ceramic insulators are used for very high gradient DC guns. These insulators are difficult to manufacture, require long commissioning times, and have poor reliability, in part because energetic electrons bury themselves in the ceramic, creating a buildup of charge and causing eventual puncture. A novel ceramic manufacturing process is proposed. It will incorporate bulk resistivity in the region where it is needed to bleed off accumulated charge caused by highly energetic electrons. This process will be optimized to provide an appropriate gradient in bulk resistivity from the vacuum side to the air side of the HV standoff ceramic cylinder. A computer model will be used to determine the optimum cylinder dimensions and required resistivity gradient for an example RF gun application. A ceramic material example with resistivity gradient appropriate for use as a DC gun insulator will be fabricated by glazing using doping compounds and tested.

  11. Design Considerations for Very High Frequency dc-dc Converters

    E-Print Network [OSTI]

    Perreault, Dave

    the gating power while ensuring fast on- off transitions of the semiconductor switch. The rectifier of switching power converters operating at greatly increased switching frequencies. Greatly increasedDesign Considerations for Very High Frequency dc-dc Converters Juan M. Rivas, David Jackson, Olivia

  12. Aalborg Universitet Power flow analysis for DC voltage droop controlled DC microgrids

    E-Print Network [OSTI]

    Vasquez, Juan Carlos

    Aalborg Universitet Power flow analysis for DC voltage droop controlled DC microgrids Li, Chendan). Power flow analysis for DC voltage droop controlled DC microgrids. In Proceedings of the 11th.aau.dk on: juli 07, 2015 #12;Power flow analysis for DC voltage droop controlled DC microgrids Chendan Li

  13. Triple voltage dc-to-dc converter and method

    DOE Patents [OSTI]

    Su, Gui-Jia (Knoxville, TN)

    2008-08-05

    A circuit and method of providing three dc voltage buses and transforming power between a low voltage dc converter and a high voltage dc converter, by coupling a primary dc power circuit and a secondary dc power circuit through an isolation transformer; providing the gating signals to power semiconductor switches in the primary and secondary circuits to control power flow between the primary and secondary circuits and by controlling a phase shift between the primary voltage and the secondary voltage. The primary dc power circuit and the secondary dc power circuit each further comprising at least two tank capacitances arranged in series as a tank leg, at least two resonant switching devices arranged in series with each other and arranged in parallel with the tank leg, and at least one voltage source arranged in parallel with the tank leg and the resonant switching devices, said resonant switching devices including power semiconductor switches that are operated by gating signals. Additional embodiments having a center-tapped battery on the low voltage side and a plurality of modules on both the low voltage side and the high voltage side are also disclosed for the purpose of reducing ripple current and for reducing the size of the components.

  14. Multi-Level DC/DC Power Conversion System with Multiple DC Sources

    E-Print Network [OSTI]

    Tolbert, Leon M.

    boost converter. Experimental results are provided to confirm the analysis and control concept. I, instead of connecting all batteries in series as one power source and a bi-directional boost converter. INTRODUCTION Traditional dc/dc converters require at least one inductive component, which is bulky, heavy

  15. DC-DC converter current source fed naturally commutated brushless DC motor drive 

    E-Print Network [OSTI]

    Khopkar, Rahul Vijaykumar

    2004-11-15

    the hard switchings by natural turn-off, thereby eliminating the heatsinks as well as the large dc link capacitor. A controlled rectifier together with a large inductor act as the current source. The only disadvantage is the large value of the dc link...

  16. Bi-Directional DC-DC Converter for PHEV Applications

    SciTech Connect (OSTI)

    Abas Goodarzi

    2011-01-31

    Plug-In Hybrid Electric Vehicles (PHEV) require high power density energy storage system (ESS) for hybrid operation and high energy density ESS for Electric Vehicle (EV) mode range. However, ESS technologies to maximize power density and energy density simultaneously are not commercially feasible. The use of bi-directional DC-DC converter allows use of multiple energy storage, and the flexible DC-link voltages can enhance the system efficiency and reduce component sizing. This will improve fuel consumption, increase the EV mode range, reduce the total weight, reduce battery initial and life cycle cost, and provide flexibility in system design.

  17. Performance Study of K2CsSb Photocathode inside a DC High Voltage Gun

    SciTech Connect (OSTI)

    T. Rao, J. Smedley, J.M. Grames, R. Mammei, J.L. McCarter, M. Poelker, R. Suleiman

    2011-03-01

    In the past decade, there has been considerable interest in the generation of tens of mA average current in a photoinjector. Until recently, GaAs:Cs cathodes and K2CsSb cathodes have been tested successfully in DC and RF injectors respectively for this application. Our goal is to test the GaAs:Cs in RF injector and the K2CsSb cathode in the DC gun in order to widen our choices. Since the multialkali cathode is a compound with uniform stochiometry over its entire thickness, we anticipate that the life time issues seen in GaAs:Cs due surface damage by ion bombardment would be minimized with this material. Hence successful operation of the K2CsSb cathode in DC gun could lead to a relatively robust electron source capable of delivering ampere level currents. In order to test the performance of K2CsSb cathode in a DC gun, we have designed and built a load lock system that would allow the fabrication of the cathode at BNL and its testing at JLab. In this paper, we will present the design of the load-lock system, cathode fabrication, and the cathode performance in the preparation chamber and in the DC gun.

  18. DC Pro Software Tool Suite

    SciTech Connect (OSTI)

    2009-04-01

    This fact sheet describes how DOE's Data Center Energy Profiler (DC Pro) Software Tool Suite and other resources can help U.S. companies identify ways to improve the efficiency of their data centers.

  19. Catalog of DC Appliances and Power Systems

    SciTech Connect (OSTI)

    Garbesi, Karina; Vossos, Vagelis; Shen, Hongxia

    2010-10-13

    This document catalogs the characteristics of current and potential future DC products and power systems.

  20. Interaction of DC-DC converters and submarine power cables in offshore wind farm DC networks 

    E-Print Network [OSTI]

    Wood, Thomas Benedict

    2014-06-30

    Offshore wind power is attracting increasing levels of research and investment. The use of HVDC transmission and the development of DC grids are topics with similar high levels of interest that go hand in hand with the ...

  1. International Conference on Advanced Ceramics and Composites, January 2007, Daytona FL, USA

    E-Print Network [OSTI]

    Yildiz, Bilge

    Proc. 31st International Conference on Advanced Ceramics and Composites, January 2007, Daytona FL design of electrodes with improved #12;Proc. 31st International Conference on Advanced Ceramics

  2. Generating Isolated Outputs in a Multilevel Modular Capacitor Clamped DC-DC Converter

    E-Print Network [OSTI]

    Tolbert, Leon M.

    -dc converters based on inductive energy transfer method (IETM) such as buck, boost, and buck-boost converter967 Generating Isolated Outputs in a Multilevel Modular Capacitor Clamped DC-DC Converter (MMCCC clamped dc-dc converter. The multilevel modular capacitor clamped converter (MMCCC) has several key

  3. DOE - Office of Legacy Management -- Armour Fertilizer Works - FL 01

    Office of Legacy Management (LM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield Municipal Gas &SCE-SessionsSouth Dakota Edgemont, South Dakota,You areFertilizer Works - FL 01

  4. File:EIA-FL-BOE.pdf | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QAsource History View New Pages Recent Changes AllApschem.pdf Jump to:ColoradoBOE.pdfFL-BOE.pdf Jump to: navigation,

  5. File:EIA-FL-GAS.pdf | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QAsource History View New Pages Recent Changes AllApschem.pdf Jump to:ColoradoBOE.pdfFL-BOE.pdf Jump to:

  6. File:EIA-FL-LIQ.pdf | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QAsource History View New Pages Recent Changes AllApschem.pdf Jump to:ColoradoBOE.pdfFL-BOE.pdf Jump to:LIQ.pdf Jump

  7. S M Stoller Star Center-WWNA Monthly; Largo, FL

    Office of Legacy Management (LM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield Municipal Gas &SCE-SessionsSouthReport for the WeldonB100 Monthly/Effluent; Largo, FL 7030-2267170

  8. S M Stoller Star Center-WWNA Monthly; Largo, FL

    Office of Legacy Management (LM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield Municipal Gas &SCE-SessionsSouthReport for the WeldonB100 Monthly/Effluent; Largo, FL

  9. Light-weight DC to very high voltage DC converter

    DOE Patents [OSTI]

    Druce, R.L.; Kirbie, H.C.; Newton, M.A.

    1998-06-30

    A DC-DC converter capable of generating outputs of 100 KV without a transformer comprises a silicon opening switch (SOS) diode connected to allow a charging current from a capacitor to flow into an inductor. When a specified amount of charge has flowed through the SOS diode, it opens up abruptly; and the consequential collapsing field of the inductor causes a voltage and current reversal that is steered into a load capacitor by an output diode. A switch across the series combination of the capacitor, inductor, and SOS diode closes to periodically reset the SOS diode by inducing a forward-biased current. 1 fig.

  10. Switching coordination of distributed dc-dc converters for highly efficient photovoltaic power plants

    DOE Patents [OSTI]

    Agamy, Mohammed; Elasser, Ahmed; Sabate, Juan Antonio; Galbraith, Anthony William; Harfman Todorovic, Maja

    2014-09-09

    A distributed photovoltaic (PV) power plant includes a plurality of distributed dc-dc converters. The dc-dc converters are configured to switch in coordination with one another such that at least one dc-dc converter transfers power to a common dc-bus based upon the total system power available from one or more corresponding strings of PV modules. Due to the coordinated switching of the dc-dc converters, each dc-dc converter transferring power to the common dc-bus continues to operate within its optimal efficiency range as well as to optimize the maximum power point tracking in order to increase the energy yield of the PV power plant.

  11. Performance Study of K2CsSb Photocathode Inside a DC High Voltage Gun

    SciTech Connect (OSTI)

    McCarter J. L.; Rao T.; Smedley, J.; Grames, J.; Mammei, R.; Poelker, M.; Suleiman, R.

    2011-09-01

    In the past decade, there has been considerable interest in the generation of tens of mA average current in a photoinjector. Until recently, GaAs:Cs cathodes and K{sub 2}CsSb cathodes have been tested successfully in DC and RF injectors respectively for this application. Our goal is to test the K{sub 2}CsSb photocathode inside a DC gun. Since the multialkali cathode is a compound with constant characteristics over its entire thickness, we anticipate that the lifetime issues seen in GaAs:Cs due to surface damage by ion bombardment would be minimized. Hence successful operation of the K{sub 2}CsSb cathode in a DC gun could lead to a relatively robust electron source capable of delivering ampere level currents. In order to test the performance of a K{sub 2}CsSb cathode in a DC gun, we have designed and built a load lock system that allows the fabrication of the cathode at Brookhaven National Lab (BNL) and its testing at Jefferson Lab (JLab). In this paper, we will present the performance of the K{sub 2}CsSb photocathode in the preparation chamber and in the DC gun.

  12. DC to DC power converters and methods of controlling the same

    SciTech Connect (OSTI)

    Steigerwald, Robert Louis; Elasser, Ahmed; Sabate, Juan Antonio; Todorovic, Maja Harfman; Agamy, Mohammed

    2012-12-11

    A power generation system configured to provide direct current (DC) power to a DC link is described. The system includes a first power generation unit configured to output DC power. The system also includes a first DC to DC converter comprising an input section and an output section. The output section of the first DC to DC converter is coupled in series with the first power generation unit. The first DC to DC converter is configured to process a first portion of the DC power output by the first power generation unit and to provide an unprocessed second portion of the DC power output of the first power generation unit to the output section.

  13. Catalog of DC Appliances and Power Systems

    E-Print Network [OSTI]

    Garbesi, Karina

    2012-01-01

    5V DC USB power from wall sockets. .. 52 viprovides 5V DC USB power from wall sockets. Reproduced withPower over Ethernet 51 Universal Serial Bus Wall

  14. Catalog of DC Appliances and Power Systems

    E-Print Network [OSTI]

    Garbesi, Karina

    2012-01-01

    main conclusions about off-grid markets for DC appliances,and power systems. Mature Off-Grid Markets for DC Appliancesapplications include off-grid residential, telecom, remote

  15. Catalog of DC Appliances and Power Systems

    E-Print Network [OSTI]

    Garbesi, Karina

    2012-01-01

    AEE Solar. 2010 Renewable Energy Design Guide and Catalog.2009, 2010, Interstate Renewable Energy Council. RetrievedDC) generated by on-site renewable energy systems in its DC

  16. Ecological benefits of dc power transmission

    SciTech Connect (OSTI)

    Kutuzova, N. B.

    2011-05-15

    The environmental effects of dc overhead transmission lines are examined. The major effects of ac and dc transmission lines are compared. Dc lines have advantages compared to ac lines in terms of electrical safety for people under the lines, biological effects, corona losses, and clearance width.

  17. Analysis and Optimization of Switched-Capacitor DC-DC Converters

    E-Print Network [OSTI]

    Sanders, Seth

    on conduction loss) of a ladder-type converter is found to be superior to that of a conventional boost converterAnalysis and Optimization of Switched-Capacitor DC-DC Converters Michael D. Seeman, Seth R. Sanders­ Analysis methods are developed that fully determine a switched-capacitor (SC) dc-dc converter's steady

  18. QER Public Meeting in Washington, DC: Enhancing Energy Infrastructure...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Washington, DC: Enhancing Energy Infrastructure Resiliency and Addressing Vulnerabilities QER Public Meeting in Washington, DC: Enhancing Energy Infrastructure Resiliency and...

  19. ASME Symposium on Modeling and Control Electrohydraulic Systems, Orlando, FL. November, 2000

    E-Print Network [OSTI]

    Li, Perry Y.

    ASME Symposium on Modeling and Control Electrohydraulic Systems, Orlando, FL. November, 2000 1 not present in previous models. The model has been coded in Simulink and experimentally validated. I

  20. Student Disability Services 240 O'Leary Library , 61 Wilder Street Fl-2

    E-Print Network [OSTI]

    Massachusetts at Lowell, University of

    Student Disability Services 240 O'Leary Library , 61 Wilder Street Fl-2 Lowell, Massachusetts 01854 Disability Services 240 O'Leary Library, 61 Wilder Street Lowell, MA 01854 Disability@uml.edu Phone: (978

  1. Rare Earth ? N = N* fs fGHZ fp nH fl

    E-Print Network [OSTI]

    Walter, Frederick M.

    Rare Earth ? #12;N to date N = N* fs fGHZ fp nH fl ·N* = 4 x 1011 ·fs = 0.2 ·fGHZ = 0.1 ·fp = 0.8 ·nH = 2 ·fl = 1.0 N = 1.3 x 1010 #12;The Goldilocks Effect Earth is "Just Right" Yes, life on Earth has adapted to Earth, but ... Earth has just the right mass to be ·Tectonically-active ·Retain

  2. Catalog of DC Appliances and Power Systems

    E-Print Network [OSTI]

    Garbesi, Karina

    2012-01-01

    mainly fluorescent and LED lighting and DC ceiling fans. TheFluorescent, CFL Lighting systems: LED Fluorescent and CFLlamps CFL lamps LED lamp CFL floodlight Lighting systems:

  3. Simultaneous distribution of AC and DC power

    DOE Patents [OSTI]

    Polese, Luigi Gentile

    2015-09-15

    A system and method for the transport and distribution of both AC (alternating current) power and DC (direct current) power over wiring infrastructure normally used for distributing AC power only, for example, residential and/or commercial buildings' electrical wires is disclosed and taught. The system and method permits the combining of AC and DC power sources and the simultaneous distribution of the resulting power over the same wiring. At the utilization site a complementary device permits the separation of the DC power from the AC power and their reconstruction, for use in conventional AC-only and DC-only devices.

  4. Catalog of DC Appliances and Power Systems

    E-Print Network [OSTI]

    Garbesi, Karina

    2012-01-01

    sited renewable energy market for the foreseeable future. Inup renewable energy systems increases in the future, chargerenewable energy sources [5]. If direct-DC has a future in

  5. Catalog of DC Appliances and Power Systems

    E-Print Network [OSTI]

    Garbesi, Karina

    2012-01-01

    similarly to an uninterruptible power supply. Lifetime:utility coupled with uninterruptible power requirements forloads serviced by DC uninterruptible power supplies in data

  6. SSL Demonstration: Parking Garage Lighting, Washington, DC

    SciTech Connect (OSTI)

    2013-06-01

    GATEWAY program report brief summarizing an SSL parking garage demonstration at the Dept. of Labor headquarters parking garage in Washington, DC.

  7. High-Efficiency X-Band MMIC GaN Power Amplifiers Operating as Rectifiers

    E-Print Network [OSTI]

    Popovic, Zoya

    High-Efficiency X-Band MMIC GaN Power Amplifiers Operating as Rectifiers Michael Litchfield, Scott two 10 x 100j.Lm power combined devices. The MMICs exhibit 67% and 56% power added efficiency at VDD a RF-to-DC efficiency of 64%. The output powers of the two MMIC PAs are around 3.2W. In rectifier mode

  8. Reliability Assessment of Fault-Tolerant Dc-Dc Converters for Photovoltaic Applications

    E-Print Network [OSTI]

    Liberzon, Daniel

    Reliability Assessment of Fault-Tolerant Dc-Dc Converters for Photovoltaic Applications Sairaj V in photovoltaic energy processing applications is presented. The proposed approach acknowledges the influence through several case studies. Index Terms-- Markov reliability modeling, photovoltaic systems, power

  9. Design of a very high frequency resonant boost DC-DC converter

    E-Print Network [OSTI]

    Burkhart, Justin (Justin Michael)

    2010-01-01

    THIS thesis explores the development of a very high frequency DC-DC resonant boost converter. The topology examined features low parts count and fast transient response but suffers from higher device stresses compared to ...

  10. Design and evaluation of a very high frequency dc/dc converter

    E-Print Network [OSTI]

    Pilawa-Podgurski, Robert C. N

    2007-01-01

    This thesis presents a resonant boost topology suitable for very high frequency (VHF, 30-300 MHz) dc-dc power conversion. The proposed design is a fixed frequency, fixed duty ratio resonant converter featuring low device ...

  11. Design and characterization of a radio-frequency dc/dc power converter

    E-Print Network [OSTI]

    Jackson, David A. (David Alexander)

    2005-01-01

    The use of radio-frequency (RF) amplifier topologies in dc/dc power converters allows the operating frequency to be increased by more than two orders of magnitude over the frequency of conventional converters. This enables ...

  12. Radio frequency dc-dc converters : device characterization, topology evaluation, and design

    E-Print Network [OSTI]

    Leitermann, Olivia

    2008-01-01

    High frequency power conversion is attractive for the opportunities it affords for improved performance. Dc-dc converters operating at high frequencies use smaller-valued energy storage elements, which tend to be physically ...

  13. Design and analysis of multiphase DC-DC converters with coupled inductors 

    E-Print Network [OSTI]

    Shi, Meng

    2007-09-17

    , directly coupled inductors have the benefit of low sensitivity to input variation at high frequencies. In addition, the proposed new structure for multiphase DC-DC converters has excellent current sharing performance and reduced current ripple. Computer...

  14. Computer-aided optimization of DC/DC converters for automotive applications

    E-Print Network [OSTI]

    Neugebauer, Timothy C.

    This paper investigates computer-aided optimization of DC/DC converters, with a focus on converters for dual-voltage automotive electrical systems. A new CAD optimization approach based on Monte Carlo search methods is ...

  15. Towards Fully Integrated High Temperature Wireless Sensors Using GaN-based HEMT Devices

    SciTech Connect (OSTI)

    Kuruganti, Phani Teja [ORNL; Islam, Syed K [ORNL; Huque, Mohammad A [ORNL

    2008-01-01

    Wireless sensors which are capable of working at extreme environments can significantly improve the efficiency and performance of industrial processes by facilitating better control systems. GaN, a widely researched wide bandgap material, has the potential to be used both as a sensing material and to fabricate control electronics, making it a prime candidate for high temperature integrated wireless sensor fabrication. In this paper we are presenting an experimental study on AlGaN/GaN HEMT's performance at higher temperature (up to 300 C). From test results, DC and microwave parameters at different temperatures were extracted.

  16. The capacitively coupled converter (C³) for high power DC-DC conversion 

    E-Print Network [OSTI]

    Khan, Shahriar

    1992-01-01

    THE CAPACITIVELY COUPLED CONVERTER (C3) FOR HIGH POWER DC-DC CONVERSION A Thesis by SHAHRIAR KHAN Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER... OF SCIENCE May 1992 Major Subject: Electrical Engineering THE CAPACITIVELY COUPLED CONVERTER (Cs) FOR HIGH POWER DC-DC CONVERSION A Thesis by SHAHRIAR KHAN Approved as to style and content by: Mehrdad Ehsani (Chair of Committee) Prasad Enjeti...

  17. High Speed CMOS Output Stage for Integrated DC-DC Converters Wai Tung Ng*, Marian Changl

    E-Print Network [OSTI]

    Ng, Wai Tung

    to attain maximum channel width per unit area for low on-resistance. A typical MF layout and its equivalent DC/DC converters is characterized by power conversion efficiency, transient response, size and cost is introduced to enhance the switching speed and power conversion efficiency of low voltage integrated DC

  18. Design and development of a DC-DC converter for a fuel cell inverter system 

    E-Print Network [OSTI]

    Gopinath, Rajesh

    2001-01-01

    (FEC)' organized by the Department of Energy and IEEE in August 2001. An efficient 3-terminal DC-DC push-pull topology was adopted to meet the performance and stringent cost constraints. A broad overview of the DC-AC inverter and its control is also...

  19. High Voltage DC Transmission 2 1.0 Introduction

    E-Print Network [OSTI]

    McCalley, James D.

    1 High Voltage DC Transmission 2 1.0 Introduction Interconnecting HVDC within an AC system requires conversion from AC to DC and inversion from DC to AC. We refer to the circuits which provide conversion from AC to DC as rectifiers and the circuits which provide conversion from DC to AC as inverters. The term

  20. High voltage DC power supply

    DOE Patents [OSTI]

    Droege, Thomas F. (Batavia, IL)

    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.

  1. High voltage DC power supply

    DOE Patents [OSTI]

    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.

  2. DC-based magnetic field controller

    DOE Patents [OSTI]

    Kotter, Dale K. (Shelley, ID); Rankin, Richard A. (Ammon, ID); Morgan, John P,. (Idaho Falls, ID)

    1994-01-01

    A magnetic field controller for laboratory devices and in particular to dc operated magnetic field controllers for mass spectrometers, comprising a dc power supply in combination with improvements to a hall probe subsystem, display subsystem, preamplifier, field control subsystem, and an output stage.

  3. Testing a GaAs cathode in SRF gun

    SciTech Connect (OSTI)

    Wang, E.; Kewisch, J.; Ben-Zvi, I.; Burrill, A.; Rao, T.; Wu, Q.; Holmes, D.

    2011-03-28

    RF electron guns with a strained superlattice GaAs cathode are expected to generate polarized electron beams of higher brightness and lower emittance than do DC guns, due to their higher field gradient at the cathode's surface and lower cathode temperature. We plan to install a bulk GaAs:Cs in a SRF gun to evaluate the performance of both the gun and the cathode in this environment. The status of this project is: In our 1.3 GHz 1/2 cell SRF gun, the vacuum can be maintained at nearly 10{sup -12} Torr because of cryo-pumping at 2K. With conventional activation of bulk GaAs, we obtained a QE of 10% at 532 nm, with lifetime of more than 3 days in the preparation chamber and have shown that it can survive in transport from the preparation chamber to the gun. The beam line has been assembled and we are exploring the best conditions for baking the cathode under vacuum. We report here the progress of our test of the GaAs cathode in the SRF gun. Future particle accelerators, such as eRHIC and the ILC require high-brightness, high-current polarized electrons. Strained superlattice GaAs:Cs has been shown to be an efficient cathode for producing polarized electrons. Activation of GaAs with Cs,O(F) lowers the electron affinity and makes it energetically possible for all the electrons, excited into the conduction band that drift or diffuse to the emission surface, to escape into the vacuum. Presently, all operating polarized electron sources, such as the CEBAF, are DC guns. In these devices, the excellent ultra-high vacuum extends the lifetime of the cathode. However, the low field gradient on the photocathode's emission surface of the DC guns limits the beam quality. The higher accelerating gradients, possible in the RF guns, generate a far better beam. Until recently, most RF guns operated at room temperature, limiting the vacuum to {approx}10{sup -9} Torr. This destroys the GaAs's NEA surface. The SRF guns combine the excellent vacuum conditions of DC guns and the high accelerating gradient of the RF guns, potentially offering a long lived cathode with very low emittance. Testing this concept requires preparation of the cathode, transportation to the SRF gun and evaluation of the performance of the cathode and the gun at cryogenic temperatures. In our work at BNL, we successfully activated the bulk GaAs in the preparation chamber. The highest quantum efficient was 10% at 532 nm that fell to 0.5% after 100 hours. We explored three different ways to activate the GaAs. We verified that the GaAs photocathode remains stable for 30 hours in a 10{sup -11} Torr vacuum. Passing the photocathode through the low 10{sup -9} Torr transfer section in several seconds caused the QE to drop to 0.8%. The photocathode with 0.8% QE can be tested for the SRF gun. The gun and beam pipe were prepared and assembled. After baking at 200 C baking, the vacuum of the gun and beam pipe can sustain a low 10{sup -11} Torr at room temperature. The final test to extract electrons from the gun is ongoing. In this paper, we discuss our progress with this SRF gun and the results of the photocathode in preparation chamber and in magnet transfer line.

  4. Alcohol Outlets and Violent Crime in Washington D.C.

    E-Print Network [OSTI]

    Franklin, F. Abron; LaVeist, Thomas A.; Webster, Daniel W.; Pan, William K.

    2010-01-01

    of Violence and Disorder. Washington, D.C. : The Urbanand Violent Crime in Washington D.C. F. Abron Franklin II,Involvement in Crime. Washington, D.C. : U.S. Department of

  5. EA-351 DC Energy Dakota, LLC | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Dakota, LLC Order authorizing DC Energy Dakota, LLC to export electric energy to Canada EA-351 DC Energy Dakota, LLC More Documents & Publications Application to Export...

  6. INL Efficiency and Security Testing of EVSE, DC Fast Chargers...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    and Security Testing of EVSE, DC Fast Chargers, and Wireless Charging Systems INL Efficiency and Security Testing of EVSE, DC Fast Chargers, and Wireless Charging Systems...

  7. Report Now Available: DC Microgrids Scoping Study--Estimate of...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Report Now Available: DC Microgrids Scoping Study--Estimate of Technical and Economic Benefits (March 2015) Report Now Available: DC Microgrids Scoping Study--Estimate of Technical...

  8. Energy Department Completes Cool Roof Installation on DC Headquarters...

    Energy Savers [EERE]

    Energy Department Completes Cool Roof Installation on DC Headquarters Building to Save Money by Saving Energy Energy Department Completes Cool Roof Installation on DC Headquarters...

  9. AVTA: Battery Testing - DC Fast Charging's Effects on PEV Batteries...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Battery Testing - DC Fast Charging's Effects on PEV Batteries AVTA: Battery Testing - DC Fast Charging's Effects on PEV Batteries The Vehicle Technologies Office's Advanced Vehicle...

  10. AVTA: Hasdec DC Fast Charging Testing Results | Department of...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Hasdec DC Fast Charging Testing Results AVTA: Hasdec DC Fast Charging Testing Results The Vehicle Technologies Office's Advanced Vehicle Testing Activity carries out testing on a...

  11. Low Cost, High Temperature, High Ripple Current DC Bus Capacitors...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Low Cost, High Temperature, High Ripple Current DC Bus Capacitors Low Cost, High Temperature, High Ripple Current DC Bus Capacitors 2010 DOE Vehicle Technologies and Hydrogen...

  12. AlGaN/GaN-based power semiconductor switches

    E-Print Network [OSTI]

    Lu, Bin, Ph. D. Massachusetts Institute of Technology

    2013-01-01

    AlGaN/GaN-based high-electron-mobility transistors (HEMTs) have great potential for their use as high efficiency and high speed power semiconductor switches, thanks to their high breakdown electric field, mobility and ...

  13. NOISE AND OPTIMIZATION OF THE dc SQUID

    E-Print Network [OSTI]

    Tesche, Claudia Denke

    2011-01-01

    unpublished). A. Van der Ziel, Noise (Prentice-Hall, Inc. ,MAY 29 19ft LBL-8510 MASTER NOISE AND OPTIMIZATION OF THE deW-7405-ENG-48 LBL-8510 NOISE AND OPTIMIZATION OF THE dc

  14. Catalog of DC Appliances and Power Systems

    E-Print Network [OSTI]

    Garbesi, Karina

    2012-01-01

    DC/AC-Hybrid) LED AC LED Power (W) Figure 8. Efficacywith the same power consumption. For LEDs, the improvementLED light-emitting diode viii lumen a measure of the power

  15. DC High School Science Bowl Regionals

    Broader source: Energy.gov [DOE]

    This event is the Washington, D.C. High School Regional competition for the US National Science Bowl. The regional competition is run by the Office of Economic Impact and Diversity, and the...

  16. Catalog of DC Appliances and Power Systems

    E-Print Network [OSTI]

    Garbesi, Karina

    2012-01-01

    direct-DC. The timing of EV charging relative to PV outputadded a hypothetical EV charging load. The EV load could bewith building loads. EV charging standards [26, 27

  17. Catalog of DC Appliances and Power Systems

    E-Print Network [OSTI]

    Garbesi, Karina

    2012-01-01

    Ovens Electric Heat Pumps Geothermal Heat Pumps Solar WaterOvens Appliance DC-internal product power (Watts) Personal Computers and Related Equipment Rechargeable Electronics Refrigerators Room Air Conditioners Security Systems Solar

  18. Catalog of DC Appliances and Power Systems

    E-Print Network [OSTI]

    Garbesi, Karina

    2012-01-01

    produce a DC-compatible dishwasher that uses 51% less energyCooking Equipments Dishwashers Lighting Electric Other Waterby end-Use ( TWh) Dishwashers DVDs/VCRs DVDs/VCRs Freezers

  19. Published in: Wet-Weather Flow in the Urban Watershed: Technology and Management. Edited by R. Field and D. Sullivan. CRC Press. Boca Raton, FL. 2002.

    E-Print Network [OSTI]

    Pitt, Robert E.

    . Field and D. Sullivan. CRC Press. Boca Raton, FL. 2002. SLAMM, the Source Loading and Management Model

  20. American Institute of Aeronautics and Astronautics Active System Identification of a DC-DC Converter Using

    E-Print Network [OSTI]

    American Institute of Aeronautics and Astronautics 1 Active System Identification of a DC and Computer Engineering, UCB 425. #12;American Institute of Aeronautics and Astronautics 2 analysis10

  1. FL47CH15-Goldstein ARI 25 November 2014 9:45 Green Algae as Model

    E-Print Network [OSTI]

    Goldstein, Raymond E.

    FL47CH15-Goldstein ARI 25 November 2014 9:45 Green Algae as Model Organisms for Biological Fluid green algae, spanning from the unicellular Chlamydomonas to multicellular Volvox, have emerged as model of flagellar synchronization. Green algae are well suited to the study of such problems because of their range

  2. SAND2013-4882 C 39th IEEE Photovoltaic Specialists Conference, Tampa, FL, June 2013

    E-Print Network [OSTI]

    SAND2013-4882 C 39th IEEE Photovoltaic Specialists Conference, Tampa, FL, June 2013 Testing National Laboratories, Albuquerque, NM, 87123, USA Abstract -- Photovoltaic (PV) modules with attached designed for AC modules. Index Terms -- inverters, photovoltaic systems, power electronics, solar energy. I

  3. Eddy-current interaction with an ideal crack. II. The inverse problem John FL Bowler

    E-Print Network [OSTI]

    Bowler, John R.

    Eddy-current interaction with an ideal crack. II. The inverse problem John FL Bowler The University 1994) Eddy-current inversion is the process whereby the geometry of a flaw in a metal is derived from eddy-current probe impedance measurements. The approach is based on an optimization scheme that seeks

  4. Theory of eddy current inversion Stephen:J. Nortona) and John FL Bowler

    E-Print Network [OSTI]

    Bowler, John R.

    Theory of eddy current inversion Stephen:J. Nortona) and John FL Bowler University of Surrey) The inverse eddy current problem can be described as the task of reconstructing an unknown distribution of electrical conductivity from eddy-current probe impedance measurements recorded as a function of probe

  5. High quality crystalline YBa2Cu307+ films on thin silicon substrates FL Haakenaasen

    E-Print Network [OSTI]

    Golovchenko, Jene A.

    High quality crystalline YBa2Cu307+ films on thin silicon substrates FL Haakenaasen Department) films with near perfect crystallinity have been grown epitaxially on Si(100) using two intermediate good crystallinity and be quite thin ((1 m)? Relativistic electrons are sent through the crystal

  6. Freezing, melting, nonwetting, and coexistence in (KCl)32 John P. Rose and FL Stephen Berry

    E-Print Network [OSTI]

    Berry, R. Stephen

    Freezing, melting, nonwetting, and coexistence in (KCl)32 John P. Rose and FL Stephen Berry that of homogeneousclusters. The melting and freezing, nonwetting, and the complexity of the potential surfaceof (KC1)33areCl clustersexhibit simpleisomerizationdynamics, large NaCl clusters exhibit freezing/melting behavior sim- ilar

  7. INDEX TO VOLUME 54 . AcanLhuridao, surgeon fish______________________ fl8

    E-Print Network [OSTI]

    INDEX TO VOLUME 54 Page . AcanLhuridao, surgeon fish______________________ fl8 'Acipcnscr .fll~' STATE OF MICI-IlqAN WAT~;RS Ob' GREEN HAY __ 1-:14 cacrulca, SartlinopL ___________________________ 20 L:n, 1:{8 Cn.~piol(/ cas1Jia.__ ___ _ ______ ________ 60 Cating, .Jamcs P.: DETI'RMING AnE .w ATI.AN

  8. FL43CH19-Shelley ARI 10 September 2010 19:30 Flapping and Bending Bodies

    E-Print Network [OSTI]

    Shelley, Michael

    FL43CH19-Shelley ARI 10 September 2010 19:30 R E V I E W S IN A D V A N CE Flapping and Bending, flutter, flexible bodies, instability, drag reduction Abstract The flapping or bending of a flexible is important to applications such as paper processing (Watanabe et al. 2002), as well as to possible approaches

  9. International Technical Conference on Coal Utilization & Fuel Systems Clearwater (FL), USA, March 4-7, 2002

    E-Print Network [OSTI]

    Zevenhoven, Ron

    is slowly shifting its fuel consumption to renewable fuels like wood and waste-derived fuels, there still27th International Technical Conference on Coal Utilization & Fuel Systems Clearwater (FL), USA of the greenhouse gas CO2 from flue gases from fossil fuel-fired power plants and utilities may be accomplished

  10. St. Petersburg, FL: Vehicle Use of Recycled Natural Gas Derived from Wastewater Biosolids

    Office of Energy Efficiency and Renewable Energy (EERE)

    Breakout Session 3A—Conversion Technologies III: Energy from Our Waste—Will we Be Rich in Fuel or Knee Deep in Trash by 2025? St. Petersburg, FL: Vehicle Use of Recycled Natural Gas Derived from Wastewater Biosolids William Eleazer, Supervising Engineer, Brown and Caldwell

  11. Formal Aspects of Computing (1995) 7(E): 30--65 fl 1995 BCS Formal Aspects

    E-Print Network [OSTI]

    Smith, Graeme

    1995-01-01

    Formal Aspects of Computing (1995) 7(E): 30--65 c fl 1995 BCS Formal Aspects of Computing A Fully of existing specification lan­ guages have been extended to incorporate object­oriented concepts [DKR91b, SBC, however, is only possible once a formal semantics of the incorporated object­oriented features has been

  12. Improved DC Gun Insulator Assembly

    SciTech Connect (OSTI)

    Sah, R.; Dudas, A.; Neubauer, M. L.; Poelker, M.; Surles-Law, K. E.L.

    2010-05-23

    Many user fa­cil­i­ties such as syn­chrotron ra­di­a­tion light sources and free elec­tron lasers re­quire ac­cel­er­at­ing struc­tures that sup­port elec­tric fields of 10-100 MV/m, es­pe­cial­ly at the start of the ac­cel­er­a­tor chain where ce­ram­ic in­su­la­tors are used for very high gra­di­ent DC guns. These in­su­la­tors are dif­fi­cult to man­u­fac­ture, re­quire long com­mis­sion­ing times, and often ex­hib­it poor re­li­a­bil­i­ty. Two tech­ni­cal ap­proach­es to solv­ing this prob­lem will be in­ves­ti­gat­ed. First­ly, in­vert­ed ce­ram­ics offer so­lu­tions for re­duced gra­di­ents be­tween the elec­trodes and ground. An in­vert­ed de­sign will be pre­sent­ed for 350 kV, with max­i­mum gra­di­ents in the range of 5-10 MV/m. Sec­ond­ly, novel ce­ram­ic man­u­fac­tur­ing pro­cess­es will be stud­ied, in order to pro­tect triple junc­tion lo­ca­tions from emis­sion, by ap­ply­ing a coat­ing with a bulk re­sis­tiv­i­ty. The pro­cess­es for cre­at­ing this coat­ing will be op­ti­mized to pro­vide pro­tec­tion as well as be used to coat a ce­ram­ic with an ap­pro­pri­ate gra­di­ent in bulk re­sis­tiv­i­ty from the vac­u­um side to the air side of an HV stand­off ce­ram­ic cylin­der. Ex­am­ple in­su­la­tor de­signs are being com­put­er mod­elled, and in­su­la­tor sam­ples are being man­u­fac­tured and test­ed

  13. A DC-DC Converter-Based PEM Fuel Cell System Emulator

    E-Print Network [OSTI]

    Boyer, Edmond

    A DC-DC Converter-Based PEM Fuel Cell System Emulator Daoud Rezzak, Farid Khoucha, Mohamed Benbouzid, Abdelaziz Kheloui and Abdeslam Mamoune Abstract--The Proton Exchange Membrane Fuel Cell (PEMFC power supplies. Fuel cell systems are characterized by high costs and complex auxiliary devices

  14. DC's Marble ceiling : urban height and its regulation in Washington, DC

    E-Print Network [OSTI]

    Trueblood, Andrew Tyson

    2009-01-01

    Washington, DC has a unique urban form that is the result of a century-old law. Through the narrow lens of DC's height limit, I survey a range of topics related to urban height, starting with a review of its history of ...

  15. Method to Improve Total Dose Radiation Hardness in a CMOS dc-dc Boost

    E-Print Network [OSTI]

    Wilamowski, Bogdan Maciej

    Method to Improve Total Dose Radiation Hardness in a CMOS dc-dc Boost Converter Huadian Pan in a wide range of radiation environment, with increasing total dose radiation, The efticieney also greatly for low-power applications (1],[2]. It is known that radiation has many effects on MOSFETs

  16. Development of a 55 kW 3X DC-DC Converter for HEV Systems

    E-Print Network [OSTI]

    Tolbert, Leon M.

    efficiency provide the great potential for the very high temperature operation. The circuit parameter design converter and a traction motor to drive the vehicle. In most commercial HEV systems, the power converter, 37996 Abstract--The design of a 55 kW 3X dc-dc converter is presented for hybrid electric vehicle (HEV

  17. Time domain design of digital compensators for PWM DC-DC converters

    E-Print Network [OSTI]

    transformation and discretization. Digital PID controllers for a Buck and Boost type converters were implemented (via the various transformation algorithms), a digital compensator operates, in reality, in the sampledTime domain design of digital compensators for PWM DC-DC converters Mor Mordechai Peretz and Sam

  18. 5 kW Multilevel DC-DC Converter for Hybrid Electric and Fuel Cell Automotive

    E-Print Network [OSTI]

    Tolbert, Leon M.

    5 kW Multilevel DC-DC Converter for Hybrid Electric and Fuel Cell Automotive Applications Faisal H) for future hybrid electric vehicle and fuel cell automotive applications will be presented in this paper will impact if the 42V/14V dual bus system will be a successful and cost effective solution for future

  19. Aalborg Universitet Optimization with System Damping Restoration for Droop Controlled DC-DC

    E-Print Network [OSTI]

    Vasquez, Juan Carlos

    --The parallel operation of dc-dc converters is widely used in distribution systems and uninterruptable power supply systems. Droop control along with virtual resistance (VR) is considered a simple and reliable method for achieving wireless power sharing among converters. In order to enhance the efficiency

  20. DC WRRC Report No. 44 THE D.C. WATER RESOURCES RESEARCH CENTER

    E-Print Network [OSTI]

    District of Columbia, University of the

    . The agreements will reduce the possibility of water shortages during low flows or pollution crisis and insure for new expanded treatment facilities. Finally, the recently completed Rock Creek water shed study has#12;DC WRRC Report No. 44 THE D.C. WATER RESOURCES RESEARCH CENTER THE UNIVERSITY OF THE DISTRICT

  1. Homopolar dc motor and trapped flux brushless dc motor using high temperature superconductor materials

    SciTech Connect (OSTI)

    Crapo, A.D.; Lloyd, J.D. (Emerson Electric Co., St. Louis, MO (US))

    1991-03-01

    This paper reports on two motors designed and built for use with high temperature superconductor (HTSC) materials. They are a homopolar DC motor that will use HTSC field windings and a brushless DC motor that will use bulk HTSC material to trap flux in steel rotor poles. The HTSC field windings of the homopolar DC motor are designed to operate at 1000 Amperes/cm{sup 2} in a 0.010 Tesla (100 Gauss) field. In order to maximize torque in the homopolar DC motor, an iron magnetic circuit with small air gaps gives maximum flux for minimum Ampere turns in the field. A copper field winding version of the homopolar DC motor has been tested while the authors wait for 575 Ampere turn HTSC coils.

  2. An Exploration of the Perceptions and Utilizations of Networking Systems in Washington, D.C.

    E-Print Network [OSTI]

    Lindsey, Robynne

    2013-01-01

    Personal Interview. Washington, D.C. , July 25, 2013.Personal Interview. Washington, D.C. , August 12, 2013.Personal Interview. Washington, D.C. , July 17, 2013. 12

  3. FEDERAL COMMUNICATIONS COMMISSION Washington, DC 20554

    E-Print Network [OSTI]

    Bove Jr., V. Michael

    FCC 96­207 Before the FEDERAL COMMUNICATIONS COMMISSION Washington, DC 20554 In the Matter of a mechanism for a bit stream layer transmission standard (into which, e.g., MPEG­2 could fit) 3) The FCC: number of hours per day of digital television transmission, minimal Quality of Service specifications

  4. Halbach array DC motor/generator

    DOE Patents [OSTI]

    Merritt, Bernard T. (Livermore, CA); Dreifuerst, Gary R. (Livermore, CA); Post, Richard F. (Walnut Creek, CA)

    1998-01-01

    A new configuration of DC motor/generator is based on a Halbach array of permanent magnets. This motor does not use ferrous materials so that the only losses are winding losses and losses due to bearings and windage. An "inside-out" design is used as compared to a conventional motor/generator design. The rotating portion, i.e., the rotor, is on the outside of the machine. The stationary portion, i.e., the stator, is formed by the inside of the machine. The rotor contains an array of permanent magnets that provide a uniform field. The windings of the motor are placed in or on the stator. The stator windings are then "switched" or "commutated" to provide a DC motor/generator much the same as in a conventional DC motor. The commutation can be performed by mechanical means using brushes or by electronic means using switching circuits. The invention is useful in electric vehicles and adjustable speed DC drives.

  5. Halbach array DC motor/generator

    DOE Patents [OSTI]

    Merritt, B.T.; Dreifuerst, G.R.; Post, R.F.

    1998-01-06

    A new configuration of DC motor/generator is based on a Halbach array of permanent magnets. This motor does not use ferrous materials so that the only losses are winding losses and losses due to bearings and windage. An ``inside-out`` design is used as compared to a conventional motor/generator design. The rotating portion, i.e., the rotor, is on the outside of the machine. The stationary portion, i.e., the stator, is formed by the inside of the machine. The rotor contains an array of permanent magnets that provide a uniform field. The windings of the motor are placed in or on the stator. The stator windings are then ``switched`` or ``commutated`` to provide a DC motor/generator much the same as in a conventional DC motor. The commutation can be performed by mechanical means using brushes or by electronic means using switching circuits. The invention is useful in electric vehicles and adjustable speed DC drives. 17 figs.

  6. SUBCONTRACT REPORT: DC-DC Converter for Fuel Cell and Hybrid Vehicles

    SciTech Connect (OSTI)

    Marlino, Laura D; Zhu, Lizhi

    2007-07-01

    The goal of this project is to develop and fabricate a 5kW dc-dc converter with a baseline 14V output capability for fuel cell and hybrid vehicles. The major objectives for this dc-dc converter technology are to meet: Higher efficiency (92%); High coolant temperature,e capability (105 C); High reliability (15 Years/150,000miles); Smaller volume (5L); Lower weight (6kg); and Lower cost ($75/kW). The key technical challenge for these converters is the 105 C coolant temperatures. The power switches and magnetics must be designed to sustain these operating temperatures reliably, without a large cost/mass/volume penalty.

  7. D.C. Water Resources Research Center Annual Technical Report

    E-Print Network [OSTI]

    - DC Water and Sewer Authority (WASA) The Institutes received favorable responses from and met with the following new Advisory Board members: 1- Mr. Richard Gianni, Water Quality Manager, DC Water and Sewer

  8. Decoherence and dephasing errors caused by the dc Stark effect...

    Office of Scientific and Technical Information (OSTI)

    Decoherence and dephasing errors caused by the dc Stark effect in rapid ion transport Citation Details In-Document Search Title: Decoherence and dephasing errors caused by the dc...

  9. DC Microgrids Scoping Study: Estimate of Technical and Economic...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    applications where the end-use loads are natively DC, e.g., computers, solid-state lighting, and building networks. These early DC applications may provide higher efficiency,...

  10. Persons Who Received the DC PSC's Emergency Petition and Complaint...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Persons Who Received the DC PSC's Emergency Petition and Complaint via E-mail on August 24, 2005 Persons Who Received the DC PSC's Emergency Petition and Complaint via E-mail on...

  11. Aalborg Universitet Hierarchical Control for Multiple DC-Microgrids Clusters

    E-Print Network [OSTI]

    Vasquez, Juan Carlos

    , and energy storages (e.g., secondary battery and super capacitor) [7]­[15]. Normally, dc MGs are proposed

  12. Energy Training Session for DC Elementary School Teachers

    Broader source: Energy.gov [DOE]

    Are you an elementary school teacher in Washington, DC, looking for creative ideas to introduce energy curriculum to your students?

  13. Exploring the Raft River geothermal area, Idaho, with the dc...

    Open Energy Info (EERE)

    the dc resistivity method (Abstract) Abstract GEOTHERMAL ENERGY; GEOTHERMAL FIELDS; ELECTRICAL SURVEYS; IDAHO; GEOTHERMAL EXPLORATION; RAFT RIVER VALLEY; ELECTRIC CONDUCTIVITY;...

  14. BULLETIN O F THE UNITED STATES FISH COMMISSI~ON. 369 Vd. V, No. 24. Washington, D.C. Sept. fL8, 1885.

    E-Print Network [OSTI]

    delivered at Uentral Station in Wash- ington, where they were liatclied :hiid from which they were distribat,ed to suitable waters by car and messenger service, in accordance with a prograui approveil by tho Conimissioner

  15. Urbanisation de DC ANF Datacentres 2 Octobre 2014

    E-Print Network [OSTI]

    van Tiggelen, Bart

    Urbanisation de DC ANF Datacentres ­ 2 Octobre 2014 Cargese Urbanisation des Datacentres Romaric David david@unistra.fr Univerité de Strasbourg 2 Octobre 2014 #12;2 Urbanisation de DC ANF Datacentres constructeurs Conclusion #12;3 Urbanisation de DC ANF Datacentres ­ 2 Octobre 2014 Cargese Introduction Centre

  16. D.C. Water Resources Research Center Annual Technical Report

    E-Print Network [OSTI]

    D.C. Water Resources Research Center Annual Technical Report FY 2007 D.C. Water Resources Research of the District of Columbia (DC) Water Resources Research Institute (the Institute) for the period of March 1 relevant water resources research results and transfer information to assist policy makers and residents

  17. Aalborg Universitet Hierarchical Control for Multiple DC Microgrids Clusters

    E-Print Network [OSTI]

    Vasquez, Juan Carlos

    Aalborg Universitet Hierarchical Control for Multiple DC Microgrids Clusters Shafiee, Qobad). Hierarchical Control for Multiple DC Microgrids Clusters. I E E E Transactions on Energy Conversion, 29(4), 922. Dragicevic, J. C. Vasquez, and J. M. Guerrero, "Hierarchical Control for Multiple DC-Microgrids Clusters

  18. RF MEMS DC CONTACT SWTCHES FOR RECONFIGURABLE Presented to the

    E-Print Network [OSTI]

    Kassegne, Samuel Kinde

    RF MEMS DC CONTACT SWTCHES FOR RECONFIGURABLE ANTENNAS _______________ A Thesis Presented STATE UNIVERSITY The Undersigned Faculty Committee Approves the Thesis of Lei Zhou: RF DC Contact MEMS rock and water, water, through persistence, eventually wins. #12;vi ABSTRACT OF THE THESIS RF MEMS DC

  19. Q&A: Kristen Psaki of WeatherizeDC

    Broader source: Energy.gov [DOE]

    Roughly 20 percent of carbon emissions come from inefficient homes. The DC Project says it has found a way to mitigate emissions and create jobs, a winning combination. WeatherizeDC is the non-profit’s effort to use a community engagement model to help DC residents find green jobs and live a more energy efficient lifestyle.

  20. Energy Challenge Two: The WeatherizeDC Campaign

    Broader source: Energy.gov [DOE]

    WeatherizeDC is a campaign of The DC Project, a nonprofit based in Washington, D.C., founded by former leaders of the Obama for America campaign around a mission to advance economic and environmental justice by creating clean energy career opportunities for people who need them most.

  1. A single-inductor switching DC-DC converter with five outputs and ordered power-distributive control

    E-Print Network [OSTI]

    Le, Hanh-Phuc; Chae, Chang-Seok; Lee, Kwang-Chan; Wang, Se-Won; Cho, Gyu-Ha; Cho, Gyu-Hyeong

    2007-01-01

    integrated current mode boost converter in standard 3.3=5-Vef?ciency CMOS DC-DC boost converter with current sensingdeveloping reset ICs, boost converters for PM OLED, and SIMO

  2. Low Power DC-DC Converters and a Low Quiescent Power High PSRR Class-D Audio Amplifier 

    E-Print Network [OSTI]

    Torres, Joselyn

    2013-12-03

    High-performance DC-DC voltage converters and high-efficient class-D audio amplifiers are required to extend battery life and reduce cost in portable electronics. This dissertation focuses on new system architectures and design techniques...

  3. Design of a step-down DC-DC controller integrated circuit with adaptive dead-time control

    E-Print Network [OSTI]

    Li, Zhipeng, M. Eng. Massachusetts Institute of Technology

    2010-01-01

    A constant-frequency peak current mode synchronous step-down DC-DC controller integrated circuit has been designed with adaptive dead-time control. The adaptive dead-time control circuitry is implemented as digital ...

  4. Computer-Aided Optimization of dc/dc Converters for Automotive Applications Timothy C. Neugebauer David J. Perreault

    E-Print Network [OSTI]

    Perreault, Dave

    Computer-Aided Optimization of dc/dc Converters for Automotive Applications Timothy C. Neugebauer/dc converters, with a focus on converters for dual-voltage automotive electrical systems. A new CAD optimization is the next evolutionary step for automotive electrical systems. High-power loads will be moved to a new high

  5. Polarization-engineered GaN/InGaN/GaN tunnel diodes

    SciTech Connect (OSTI)

    Krishnamoorthy, Sriram; Nath, Digbijoy N.; Akyol, Fatih; Park, Pil Sung; Esposto, Michele; Rajan, Siddharth [Department of Electrical and Computer Engineering, Ohio State University, Columbus, Ohio 43210 (United States)

    2010-11-15

    We report on the design and demonstration of polarization-engineered GaN/InGaN/GaN tunnel junction diodes with high current density and low tunneling turn-on voltage. Wentzel-Kramers-Brillouin calculations were used to model and design tunnel junctions with narrow band gap InGaN-based barrier layers. N-polar p-GaN/In{sub 0.33}Ga{sub 0.67}N/n-GaN heterostructure tunnel diodes were grown using molecular beam epitaxy. Efficient interband tunneling was achieved close to zero bias with a high current density of 118 A/cm{sup 2} at a reverse bias of 1 V, reaching a maximum current density up to 9.2 kA/cm{sup 2}. These results represent the highest current density reported in III-nitride tunnel junctions and demonstrate the potential of III-nitride tunnel devices for a broad range of optoelectronic and electronic applications.

  6. Open-core screw dislocations in GaN epilayers observed by scanning force microscopy and high-resolution transmission electron microscopy

    E-Print Network [OSTI]

    Rohrer, Gregory S.

    -resolution transmission electron microscopy W. Qian, G. S. Rohrer, and M. Skowronski Department of Materials Science. K. Gaskill Laboratory for Advanced Material Synthesis, Naval Research Laboratory, Washington, DC of organometallic vapor phase epitaxy grown -GaN films using high-resolution transmission electron microscopy

  7. DOE - Office of Legacy Management -- University of Miami - FL 0-01

    Office of Legacy Management (LM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield Municipal Gas &SCE-SessionsSouth DakotaRobbins and Myers Co - OHStarTracerlabCincinnati -Miami - FL

  8. File:USDA-CE-Production-GIFmaps-FL.pdf | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QAsource History View New Pages RecentTempCampApplicationWorksheet 2011.pdf JumpTransmission SitingFL.pdf Jump to:

  9. S M Stoller Star Center-B100 Monthly/Effluent; Largo, FL

    Office of Legacy Management (LM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield Municipal Gas &SCE-SessionsSouthReport for the WeldonB100 Monthly/Effluent; Largo, FL 7030-226

  10. GaInNAs laser gain

    SciTech Connect (OSTI)

    CHOW,WENG W.; JONES,ERIC D.; MODINE,NORMAND A.; KURTZ,STEVEN R.; ALLERMAN,ANDREW A.

    2000-05-23

    The optical gain spectra for GaInNAs/GaAs quantum wells are computed using a microscopic laser theory. From these spectra, the peak gain and carrier radiative decay rate as functions of carrier density are determined. These dependences allow the study of the lasing threshold current density of GaInNAs/GaAs quantum well structures.

  11. Advantages of the Blue InGaN/GaN Light-Emitting Diodes with an AlGaN/GaN/AlGaN Quantum Well Structured Electron Blocking Layer

    E-Print Network [OSTI]

    Demir, Hilmi Volkan

    ABSTRACT: InGaN/GaN light-emitting diodes (LEDs) with p-(AlGaN/GaN/AlGaN) quantum well structured electron. The proposed QWEBL LED structure, in which a p-GaN QW layer is inserted in the p-AlGaN electron blocking layer the radiative recombination rates across the active region. Consequently, the light output power was enhanced

  12. 8798_FL

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservationBio-InspiredAtmosphericdevicesPPONeApril351APPLICATION OFsafer The mp483-I

  13. Red emitting photonic devices using InGaP/InGaAlP material system

    E-Print Network [OSTI]

    Kangude, Yamini

    2005-01-01

    In this thesis, two red emitting photonic devices are presented using the InGaP/InGaAlP material system. InGaP/InGaAlP material system provides large flexibility in the band gap energy while being lattice matched to GaAs ...

  14. Improved DC Gun and Insulator Assembly

    SciTech Connect (OSTI)

    Neubauer, Michael; Johnson, Rolland P

    2015-01-11

    Many user facilities such as synchrotron radiation light sources and free electron lasers rely on DC high voltage photoguns with internal field gradients as high as 10 to 15 MV/m. These high gradients often lead to field emission which poses serious problems for the photocathode used to generate the electron beam and the ceramic insulators used to bias the photocathode at high voltage. Ceramic insulators are difficult to manufacture, require long commissioning times, and have poor reliability, in part because energetic electrons bury themselves in the ceramic causing a buildup of charge and eventual puncture, and also because large diameter ceramics are difficult to braze reliably. The lifetimes of photo cathodes inside high current DC guns exhibiting field emission are limited to less than a hundred hours. Reducing the surface gradients on the metals reduces the field emission, which serves to maintain the required ultrahigh vacuum condition. A novel gun design with gradients around 5 MV/m and operating at 350 kV, a major improvement over existing designs, was proposed that allows for the in-situ replacement of photo cathodes in axially symmetric designs using inverted ceramics. In this project, the existing JLAB CEBAF asymmetric gun design with an inverted ceramic support was modeled and the beam dynamics characterized. An improved structure was designed that reduces the surface gradients and improves the beam optics. To minimize the surface gradients, a number of electrostatic gun designs were studied to determine the optimum configuration of the critical electrodes within the gun structure. Coating experiments were carried out to create a charge dissipative coating for cylindrical ceramics. The phase II proposal, which was not granted, included the design and fabrication of an axially symmetric DC Gun with an inverted ceramic that would operate with less than 5 MV/m at 350 kV and would be designed with an in-situ replaceable photo-cathode.

  15. Quantitative Outgassing studies in DC Electrical breakdown

    E-Print Network [OSTI]

    Levinsen, Yngve Inntjore; Calatroni, Sergio; Taborelli, Mauro; Wünsch, Walter

    2010-01-01

    Breakdown in the accelerating structures sets an important limit to the performance of the CLIC linear collider. Vacuum degradation and subsequent beam instability are possible outcomes of a breakdown if too much gas is released from the cavity surface. Quantitative data of gas released by breakdowns are provided for copper (milled Cu-OFE, as-received and heat-treated), and molybdenum. These data are produced in a DC spark system based on a capacitance charged at fixed energy, and will serve as a reference for the vacuum design of the CLIC accelerating structures.

  16. Dc's blog | OpenEI Community

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTIONRobertsdale, Alabama (UtilityInstruments Inc JumpIowa:Minnesota:Daylighting JumpDc's blog Home >

  17. DC Survey 2013 | National Nuclear Security Administration

    National Nuclear Security Administration (NNSA)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield Municipal Gas &SCE-SessionsSouthReport for the t-) S/,,5 'a CConversion |National Laser UserDC

  18. Washington DC | OpenEI Community

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIX ECoop IncIowa (Utility Company)Idaho)Vossloh Kiepe JumpWarana Group ofDC Home Linked

  19. A Reachability-Based Method for Large-Signal Behavior Verification of DC-DC Converters

    E-Print Network [OSTI]

    Liberzon, Daniel

    -loop, large-signal system behavior verification, and iv) switching detail modeling. In open-loop, large´inguez-Garc´ia, Member, IEEE Abstract--A method for large-signal behavior verification of power electronics DC behavior verification, lengthy time-domain simula- tions are conducted to analyze the system response

  20. Vehicle Technologies Office Merit Review 2014: DC Fast Charging...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Technologies Office Merit Review 2014: DC Fast Charging Effects on Battery Life and EVSE Efficiency and Security Testing Presentation given by Idaho National Laboratory at 2014...

  1. INL Efficiency and Security Testing of EVSE, DC Fast Chargers...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    INL Efficiency and Security Testing of EVSE, DC Fast Chargers, and Wireless Charging Systems May 14, 2013 Project ID VSS096 2013 DOE Vehicle Technologies Program Annual Merit...

  2. Washington DC Reliability Requirements and the Need to Operate...

    Energy Savers [EERE]

    DC Reliability Requirements and the Need to Operate Mirant's Potomac River Generation Station to Support Local Area Reliability (Oak Ridge National Laboratory 2005)...

  3. DC Resistivity Survey (Schlumberger Array) At Raft River Geothermal...

    Open Energy Info (EERE)

    Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: DC Resistivity Survey (Schlumberger Array) At Raft River Geothermal Area (1974-1975) Exploration...

  4. INL Efficiency and Security Testing of EVSE, DC Fast Chargers...

    Broader source: Energy.gov (indexed) [DOE]

    Testing to support Code & Standards Vehicle Technologies Office Merit Review 2014: DC Fast Charging Effects on Battery Life and EVSE Efficiency and Security Testing Vehicle...

  5. DC Bus Capacitor Manufacturing Facility for Electric Drive Vehicles...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    0 DOE Vehicle Technologies and Hydrogen Programs Annual Merit Review and Peer Evaluation Meeting, June 7-11, 2010 -- Washington D.C. apearravt028boan2010...

  6. DC Resistivity Survey (Wenner Array) At Mt Princeton Hot Springs...

    Open Energy Info (EERE)

    2008 - 2010 Usefulness useful DOE-funding Unknown Exploration Basis Determination of groundwater flux patterns Notes Researchers measured DC resistivity and produced 12 resistivity...

  7. DESIGN AND PERFORMANCE OF PEP DC POWER SYSTEMS

    E-Print Network [OSTI]

    Jackson, T.

    2010-01-01

    DC supplies, with no switchgear interposed between the DCthe only transformers and switchgear in the system, and theycost of transformers and switchgear is eliminated from the

  8. GaAs, AlGaAs and InGaP Tunnel Junctions for Multi-Junction Solar Cells Under Concentration: Resistance Study

    SciTech Connect (OSTI)

    Wheeldon, Jeffrey F.; Valdivia, Christopher E.; Walker, Alex; Kolhatkar, Gitanja; Hall, Trevor J.; Hinzer, Karin; Masson, Denis; Riel, Bruno; Fafard, Simon; Jaouad, Abdelatif; Turala, Artur; Ares, Richard; Aimez, Vincent

    2010-10-14

    The following four TJ designs, AlGaAs/AlGaAs, GaAs/GaAs, AlGaAs/InGaP and AlGaAs/GaAs are studied to determine minimum doping concentration to achieve a resistance of <10{sup -4} {omega}{center_dot}cm{sup 2} and a peak tunneling current suitable for MJ solar cells up to 1500-suns concentration (operating current of 21 A/cm{sup 2}). Experimentally calibrated numerical models are used to determine how the resistance changes as a function of doping concentration. The AlGaAs/GaAs TJ design is determined to require the least doping concentration to achieve the specified resistance and peak tunneling current, followed by the GaAs/GaAs, and AlGaAs/AlGaAs TJ designs. The AlGaAs/InGaP TJ design can only achieve resistances >5x10{sup -4} {omega}cm{sup 2}.

  9. Design and analysis of a zero-voltage switching scheme for a dc- to-dc converter 

    E-Print Network [OSTI]

    Arun, G.

    1992-01-01

    DESIGN AND ANALYSIS OF A ZERO-VOLTAGE SSVITCHING SCFIE'. tIE FOR A DC-TO-DC CONVERTER A Thesis by G. ARUN Submitted to the Office of Graduate Studies of Texas ARM 1. niversity in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE December 1992 Major Subject: Electrical Engineering DESIGN AND ANALYSIS OE A ZERO-VOLTAGE SWITCHING SCHEME I'OR A DC-TO-DC CONVERTER A Thesis by G. AR(tN Approved as to style and content by: P. Enjeti (Chair of Cornrnitteel C...

  10. GaAs MOEMS Technology

    SciTech Connect (OSTI)

    SPAHN, OLGA B.; GROSSETETE, GRANT D.; CICH, MICHAEL J.; TIGGES, CHRIS P.; RENO, JOHN L.; PEAKE, GREGORY M.; KLEM, JOHN F.; LEAN, JEN; FULLER, CHARLES T.; BURKHART, JEFF; BAUER, THOMAS; SULLIVAN, CHARLES T.

    2003-03-01

    Many MEMS-based components require optical monitoring techniques using optoelectronic devices for converting mechanical position information into useful electronic signals. While the constituent piece-parts of such hybrid opto-MEMS components can be separately optimized, the resulting component performance, size, ruggedness and cost are substantially compromised due to assembly and packaging limitations. GaAs MOEMS offers the possibility of monolithically integrating high-performance optoelectronics with simple mechanical structures built in very low-stress epitaxial layers with a resulting component performance determined only by GaAs microfabrication technology limitations. GaAs MOEMS implicitly integrates the capability for radiation-hardened optical communications into the MEMS sensor or actuator component, a vital step towards rugged integrated autonomous microsystems that sense, act, and communicate. This project establishes a new foundational technology that monolithically combines GaAs optoelectronics with simple mechanics. Critical process issues addressed include selectivity, electrochemical characteristics, and anisotropy of the release chemistry, and post-release drying and coating processes. Several types of devices incorporating this novel technology are demonstrated.

  11. Table I: Distribution Functions for Fuel Fractions Group 2L0 FL0 ( wL0

    E-Print Network [OSTI]

    Hallett, William L.H.

    Table I: Distribution Functions for Fuel Fractions Group 2L0 FL0 ( wL0 alcohols 55 20 0 0: Distribution fun ctions used to mod el the oil. Evaporation of Biomass Pyrolysis Oil Droplets - II W), and the composition of each of these groups is described by a gamma distribution function with mean 2L0, standard

  12. FORM CD-512 UNITED STATES DEPARTMENT OF COM MERCE CERTlFlCATlONS REGARDING DEBARMENT, SUSPENSION, INELIGIBILITY AND

    E-Print Network [OSTI]

    paid or will be connection with this commitment providing for the United paid, by or on behalfFORM CD-512 UNITED STATES DEPARTMENT OF COM MERCE (7-91) CERTlFlCATlONS REGARDING DEBARMENT to attest. Applicants should also review the instructions for certification included in the regulations

  13. Intense terahertz emission from molecular beam epitaxy-grown GaAs/GaSb(001)

    SciTech Connect (OSTI)

    Sadia, Cyril P.; Laganapan, Aleena Maria; Agatha Tumanguil, Mae; Estacio, Elmer; Somintac, Armando; Salvador, Arnel; Que, Christopher T.; Yamamoto, Kohji; Tani, Masahiko

    2012-12-15

    Intense terahertz (THz) electromagnetic wave emission was observed in undoped GaAs thin films deposited on (100) n-GaSb substrates via molecular beam epitaxy. GaAs/n-GaSb heterostructures were found to be viable THz sources having signal amplitude 75% that of bulk p-InAs. The GaAs films were grown by interruption method during the growth initiation and using various metamorphic buffer layers. Reciprocal space maps revealed that the GaAs epilayers are tensile relaxed. Defects at the i-GaAs/n-GaSb interface were confirmed by scanning electron microscope images. Band calculations were performed to infer the depletion region and electric field at the i-GaAs/n-GaSb and the air-GaAs interfaces. However, the resulting band calculations were found to be insufficient to explain the THz emission. The enhanced THz emission is currently attributed to a piezoelectric field induced by incoherent strain and defects.

  14. High Voltage DC Transmission 1.0 Introduction

    E-Print Network [OSTI]

    McCalley, James D.

    1 High Voltage DC Transmission 1.0 Introduction HVDC has been applied in electric power systems Supplier: ABB Railroa d DC Tie USA - Mission, TX 26°1001N9 8°1925W USA - Mission, TX 26°1001N9 8°1925W 21

  15. DC Optimal Power Flow: Uniqueness and Chee Wei Tan

    E-Print Network [OSTI]

    Tan, Chee Wei

    the minimization of power transmission loss in DC-OPF and char- acterize the uniqueness of its solutions. This hasDC Optimal Power Flow: Uniqueness and Algorithms Chee Wei TanÝ , Desmond W. H. Cai£ and Xin LouÝ Ý and transmission loss in a power net- work subject to physical constraints governed by Kirchhoff's and Ohm's law [1

  16. A 3D Magnetic Force Manipulator DC Prototype

    E-Print Network [OSTI]

    North Carolina at Chapel Hill, University of

    A 3D Magnetic Force Manipulator DC Prototype Leandra Vicci Microelectronic Systems Laboratory optical field intensities which interact strongly with many materials and may produce undesired side;Leandra Vicci A 3D Magnetic Force Manipulator DC Prototype 17 October 2001 1 Conceptual design

  17. Read-out electronics for DC squid magnetic measurements

    DOE Patents [OSTI]

    Ganther, Jr., Kenneth R. (Olathe, KS); Snapp, Lowell D. (Independence, MO)

    2002-01-01

    Read-out electronics for DC SQUID sensor systems, the read-out electronics incorporating low Johnson noise radio-frequency flux-locked loop circuitry and digital signal processing algorithms in order to improve upon the prior art by a factor of at least ten, thereby alleviating problems caused by magnetic interference when operating DC SQUID sensor systems in magnetically unshielded environments.

  18. Peter M. Vallone AAFS Washington, D.C.

    E-Print Network [OSTI]

    Peter M. Vallone AAFS Washington, D.C. February 23, 2008 http://www.cstl.nist.gov/biotech available for the purpose. Our publications and presentations are made available at: http://www.cstl.nist.gov/biotech/strbase/NISTpub.htm #12;Peter M. Vallone AAFS Washington, D.C. February 23, 2008 http://www.cstl.nist.gov/biotech

  19. Tutorial, GECCO'05, Washington D.C. Fitness Approximation

    E-Print Network [OSTI]

    Yang, Shengxiang

    1 Tutorial, GECCO'05, Washington D.C. Fitness Approximation in Evolutionary Computation Yaochu Jin Honda Research Institute Europe Khaled Rasheed University of Georgia Tutorial, GECCO'05, Washington D expensive fitness evaluations Tutorial, GECCO'05, Washington D.C. Fitness Approximation Methods · Problem

  20. National Small Business Federal Contracting Summit-DC Fall Conference

    Broader source: Energy.gov [DOE]

    The 2014 National Small Business Federal Contracting Summit - DC Fall Conference is presented jointly by the National Association of Small Business Contractors (the Supplier Council of The American Small Business Chamber of Commerce) and the U.S. Women's Chamber of Commerce in Washington DC.

  1. Dynamic microscopic theory of fusion using DC-TDHF

    SciTech Connect (OSTI)

    Umar, A. S.; Oberacker, V. E.; Keser, R.; Maruhn, J. A.; Reinhard, P.-G.

    2012-10-20

    The density-constrained time-dependent Hartree-Fock (DC-TDHF) theory is a fully microscopic approach for calculating heavy-ion interaction potentials and fusion cross sections below and above the fusion barrier. We discuss recent applications of DC-TDHF method to fusion of light and heavy systems.

  2. Historical Material Analysis of DC745U Pressure Pads

    SciTech Connect (OSTI)

    Ortiz-Acosta, Denisse [Los Alamos National Laboratory

    2012-07-30

    As part of the Enhance Surveillance mission, it is the goal to provide suitable lifetime assessment of stockpile materials. This report is an accumulation of historical publication on the DC745U material and their findings. It is the intention that the B61 LEP program uses this collection of data to further develop their understanding and potential areas of study. DC745U is a commercially available silicone elastomer consisting of dimethyl, methyl-phenyl, and methyl-vinyl siloxane repeat units. Originally, this material was manufactured by Dow Corning as Silastic{reg_sign} DC745U at their manufacturing facility in Kendallville, IN. Recently, Dow Corning shifted this material to the Xiameter{reg_sign} brand product line. Currently, DC745U is available through Xiameter{reg_sign} or Dow Corning's distributor R. D. Abbott Company. DC745U is cured using 0.5 wt% vinyl-specific peroxide curing agent known as Luperox 101 or Varox DBPH-50. This silicone elastomer is used in numerous parts, including two major components (outer pressure pads and aft cap support) in the W80 and as pressure pads on the B61. DC745U is a proprietary formulation, thus Dow Corning provides limited information on its composition and properties. Based on past experience with Dow Corning, DC745U is at risk of formulation changes without notification to the costumer. A formulation change for DC745U may have a significant impact because the network structure is a key variable in determining material properties. The purpose of this report is to provide an overview of historical DC745U studies and identify gaps that need to be addressed in future work. Some of the previous studies include the following: 1. Spectroscopic characterization of raw gum stock. 2. Spectroscopic, thermal, and mechanical studies on cured DC745U. 3. Nuclear Magnetic Resonance (NMR) and solvent swelling studies on DC745U with different crosslink densities. 4. NMR, solvent swelling, thermal, and mechanical studies on thermally aged DC745U. 5. NMR, solvent swelling, thermal, and mechanical studies on radiolytically aged DC745U. Each area is reviewed and further work is suggested to improve our understanding of DC745U for systems engineering, surveillance, aging assessments, and lifetime assessment.

  3. 1668 IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 27, NO. 4, APRIL 2012 55-kW Variable 3X DC-DC Converter for Plug-in

    E-Print Network [OSTI]

    Tolbert, Leon M.

    vehicle (HEV) traction drives. The boost converter used in commercial HEVs meets with obstacles when is shown in Fig. 1. In this system, the dc-dc converter boosts the battery voltage from 244 V to three op series-parallel HEV. speed and power demand of the vehicle. In this traditional dc- dc boost converter

  4. New leading/trailing edge modulation strategies for two-stage AC/DC PFC adapters to reduce DC-link capacitor ripple current 

    E-Print Network [OSTI]

    Sun, Jing

    2007-09-17

    PFC stage and trailing edge modulation for the second DC/DC converter stage can significantly reduce the ripple current and ripple voltage of the DC-link capacitor. Thus, a smaller DC-link capacitance can be used, lowering the cost and size of the AC...

  5. Development of a Novel Bi-Directional Isolated Multiple-Input DC-DC Converter

    SciTech Connect (OSTI)

    Li, H.

    2005-10-24

    There is vital need for a compact, lightweight, and efficient energy-storage system that is both affordable and has an acceptable cycle life for the large-scale production of electric vehicles (EVs) and hybrid electric vehicles (HEVs). Most of the current research employs a battery-storage unit (BU) combined with a fuel cell (FC) stack in order to achieve the operating voltage-current point of maximum efficiency for the FC system. A system block diagram is shown in Fig.1.1. In such a conventional arrangement, the battery is sized to deliver the difference between the energy required by the traction drive and the energy supplied by the FC system. Energy requirements can increase depending on the drive cycle over which the vehicle is expected to operate. Peak-power transients result in an increase of losses and elevated temperatures which result in a decrease in the lifetime of the battery. This research will propose a novel two-input direct current (dc) dc to dc converter to interface an additional energy-storage element, an ultracapacitor (UC), which is shown in Fig.1.2. It will assist the battery during transients to reduce the peak-power requirements of the battery.

  6. Computational analysis of thin film InGaAs/GaAs quantum well solar cells with

    E-Print Network [OSTI]

    Yu, Edward T.

    Computational analysis of thin film InGaAs/GaAs quantum well solar cells with back side light, Austin, TX 78758, USA * ety@ece.utexas.edu Abstract: Simulations of thin film (~2.5 µm thick) InGaAs/GaAs. Roberts, G. Hill, and C. Calder, "Progress in quantum well solar cells," Thin Solid Films 511­512, 76

  7. GaSb/GaAs type II quantum dot solar cells for enhanced infrared spectral response

    E-Print Network [OSTI]

    Jalali. Bahram

    into existing multijunction cells either as a means to increase the current or efficiency by using low band gapGaSb/GaAs type II quantum dot solar cells for enhanced infrared spectral response R. B infrared spectral response of GaAs-based solar cells that incorporate type II GaSb quantum dots QDs formed

  8. Abstract--A design method for digital controller of PWM DC-DC converters was developed, tested by simulations and

    E-Print Network [OSTI]

    domain transformation and discretization. A digital PID controller for a Buck type converter domain and the sampled data domain (via the various transformation algorithms), a digital compensatorAbstract-- A design method for digital controller of PWM DC-DC converters was developed, tested

  9. Phase-Shifted Full Bridge DC-DC Converter with Energy Recovery Clamp and Reduced Circulating Current

    E-Print Network [OSTI]

    Phase-Shifted Full Bridge DC-DC Converter with Energy Recovery Clamp and Reduced Circulating@aei.com Abstract - This paper introduces a full bridge converter with reduced circulating current and a reduction bridge converter operating at 32 kHz switching frequency. Losses and efficiency of the experimental

  10. Optimizing Energy Savings from Direct-DC in U.S. Residential Buildings

    E-Print Network [OSTI]

    Garbesi, Karina

    2012-01-01

    AC vs. DC distribution: A loss comparison. Transmission andof a DC microgrid for residential houses. In Transmission &DC mainly because it enabled central generation and efficient long-distance power transmission.

  11. Application to Export Electric Energy OE Docket No. EA-351 DC...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    1 DC Energy Dakota, LLC Application to Export Electric Energy OE Docket No. EA-351 DC Energy Dakota, LLC Application from DC Energy Dakota, LLC to export electric energy to Canada...

  12. New GaInP/GaAs/GaInAs, Triple-Bandgap, Tandem Solar Cell for High-Efficiency Terrestrial Concentrator Systems

    SciTech Connect (OSTI)

    Kurtz, S.; Wanlass, M.; Kramer, C.; Young, M.; Geisz, J.; Ward, S.; Duda, A.; Moriarty, T.; Carapella, J.; Ahrenkiel, P.; Emery. K.; Jones, K.; Romero, M.; Kibbler, A.; Olson, J.; Friedman, D.; McMahon, W.; Ptak, A.

    2005-11-01

    GaInP/GaAs/GaInAs three-junction cells are grown in an inverted configuration on GaAs, allowing high quality growth of the lattice matched GaInP and GaAs layers before a grade is used for the 1-eV GaInAs layer. Using this approach an efficiency of 37.9% was demonstrated.

  13. We Have a Winner - DC High School Regional Science Bowl Competition...

    Energy Savers [EERE]

    We Have a Winner - DC High School Regional Science Bowl Competition Held Last Saturday We Have a Winner - DC High School Regional Science Bowl Competition Held Last Saturday...

  14. Implementing the DC Mode in Cosmological Simulations with Supercomoving Variables

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Gnedin, Nickolay Y; Kravtsov, Andrey V; Rudd, Douglas H

    2011-06-02

    As emphasized by previous studies, proper treatment of the density fluctuation on the fundamental scale of a cosmological simulation volume - the 'DC mode' - is critical for accurate modeling of spatial correlations on scales ~> 10% of simulation box size. We provide further illustration of the effects of the DC mode on the abundance of halos in small boxes and show that it is straightforward to incorporate this mode in cosmological codes that use the 'supercomoving' variables. The equations governing evolution of dark matter and baryons recast with these variables are particularly simple and include the expansion factor, andmore »hence the effect of the DC mode, explicitly only in the Poisson equation.« less

  15. InGaAsN/GaAs heterojunction for multi-junction solar cells

    DOE Patents [OSTI]

    Kurtz, Steven R. (Albuquerque, NM); Allerman, Andrew A. (Albuquerque, NM); Klem, John F. (Albuquerque, NM); Jones, Eric D. (Edgewood, NM)

    2001-01-01

    An InGaAsN/GaAs semiconductor p-n heterojunction is disclosed for use in forming a 0.95-1.2 eV bandgap photodetector with application for use in high-efficiency multi-junction solar cells. The InGaAsN/GaAs p-n heterojunction is formed by epitaxially growing on a gallium arsenide (GaAs) or germanium (Ge) substrate an n-type indium gallium arsenide nitride (InGaAsN) layer having a semiconductor alloy composition In.sub.x Ga.sub.1-x As.sub.1-y N.sub.y with 0GaAs layer, with the InGaAsN and GaAs layers being lattice-matched to the substrate. The InGaAsN/GaAs p-n heterojunction can be epitaxially grown by either molecular beam epitaxy (MBE) or metalorganic chemical vapor deposition (MOCVD). The InGaAsN/GaAs p-n heterojunction provides a high open-circuit voltage of up to 0.62 volts and an internal quantum efficiency of >70%.

  16. Band Structure of Strain-Balanced GaAsBi/GaAsN Super-lattices on GaAs

    SciTech Connect (OSTI)

    Hwang, J.; Phillips, J. D.

    2011-05-31

    GaAs alloys with dilute content of Bi and N provide a large reduction in band-gap energy with increasing alloy composition. GaAsBi/GaAsN heterojunctions have a type-II band alignment, where superlattices based on these materials offer a wide range for designing effective band-gap energy by varying superlattice period and alloy composition. The miniband structure and effective band gap for strain-balanced GaAsBi/GaAsN superlattices with effective lattice match to GaAs are calculated for alloy compositions up to 5% Bi and N using the k·p method. The effective band gap for these superlattices is found to vary between 0.89 and 1.32 eV for period thickness ranging from 10 to 100 Å. The joint density of states and optical absorption of a 40/40 Å GaAs0.96Bi0.04/GaAs0.98N0.02 superlattice are reported demonstrating a ground-state transition at 1.005 eV and first excited transition at 1.074 eV. The joint density of states is similar in magnitude to GaAs, while the optical absorption is approximately one order of magnitude lower due to the spatially indirect optical transition in the type-II structure. The GaAsBi/GaAsN system may provide a new material system with lattice match to GaAs in a spectral range of high importance for optoelectronic devices including solar cells, photodetectors, and light emitters.

  17. Thermoelectric DC conductivities and Stokes flows on black hole horizons

    E-Print Network [OSTI]

    Elliot Banks; Aristomenis Donos; Jerome P. Gauntlett

    2015-07-15

    We consider a general class of electrically charged black holes of Einstein-Maxwell-scalar theory that are holographically dual to conformal field theories at finite charge density which break translation invariance explicitly. We examine the linearised perturbations about the solutions that are associated with the thermoelectric DC conductivity. We show that there is a decoupled sector at the black hole horizon which must solve generalised Stokes equations for a charged fluid. By solving these equations we can obtain the DC conductivity of the dual field theory. For one-dimensional lattices we solve the fluid equations to obtain closed form expressions for the DC conductivity in terms of the solution at the black hole horizon. We also determine the leading order DC conductivity for lattices that can be expanded as a perturbative series about translationally invariant solutions.

  18. Radiofrequency amplifier based on a dc superconducting quantum interference device

    DOE Patents [OSTI]

    Hilbert, C.; Martinis, J.M.; Clarke, J.

    1984-04-27

    A low noise radiofrequency amplifer, using a dc SQUID (superconducting quantum interference device) as the input amplifying element. The dc SQUID and an input coil are maintained at superconductivity temperatures in a superconducting shield, with the input coil inductively coupled to the superconducting ring of the dc SQUID. A radiofrequency signal from outside the shield is applied to the input coil, and an amplified radiofrequency signal is developed across the dc SQUID ring and transmitted to exteriorly of the shield. A power gain of 19.5 +- 0.5 dB has been achieved with a noise temperature of 1.0 +- 0.4 K at a frequency of 100 MHz.

  19. National Science Bowl Brings Best and Brightest to DC

    Broader source: Energy.gov [DOE]

    The National Science Bowl Finals in Washington D.C. April 27 to 30 pit 113 high and middle school teams against one another answering questions Jeopardy-style about biology, chemistry, earth science, physics, astronomy, and math.

  20. Thermoelectric DC conductivities and Stokes flows on black hole horizons

    E-Print Network [OSTI]

    Banks, Elliot; Gauntlett, Jerome P

    2015-01-01

    We consider a general class of electrically charged black holes of Einstein-Maxwell-scalar theory that are holographically dual to conformal field theories at finite charge density which break translation invariance explicitly. We examine the linearised perturbations about the solutions that are associated with the thermoelectric DC conductivity. We show that there is a decoupled sector at the black hole horizon which must solve generalised Stokes equations for a charged fluid. By solving these equations we can obtain the DC conductivity of the dual field theory. For one-dimensional lattices we solve the fluid equations to obtain closed form expressions for the DC conductivity in terms of the solution at the black hole horizon. We also determine the leading order DC conductivity for lattices that can be expanded as a perturbative series about translationally invariant solutions.

  1. Thermoelectric DC conductivities with momentum dissipation from higher derivative gravity

    E-Print Network [OSTI]

    Long Cheng; Xian-Hui Ge; Zu-Yao Sun

    2015-04-28

    We present a mechanism of momentum relaxation in higher derivative gravity by adding linear scalar fields to the Gauss-Bonnet theory. We analytically computed all of the DC thermoelectric conductivities in this theory by adopting the method given by Donos and Gauntlett in [arXiv:1406.4742]. The results show that the DC electric conductivity is not a monotonic function of the effective impurity parameter $\\beta$: in the small $\\beta$ limit, the DC conductivity is dominated by the coherent phase, while for larger $\\beta$, pair creation contribution to the conductivity becomes dominant, signaling an incoherent phase. In addition, the DC heat conductivity is found independent of the Gauss-Bonnet coupling constant.

  2. Thermoelectric DC conductivities and Stokes flows on black hole horizons

    E-Print Network [OSTI]

    Elliot Banks; Aristomenis Donos; Jerome P. Gauntlett

    2015-10-11

    We consider a general class of electrically charged black holes of Einstein-Maxwell-scalar theory that are holographically dual to conformal field theories at finite charge density which break translation invariance explicitly. We examine the linearised perturbations about the solutions that are associated with the thermoelectric DC conductivity. We show that there is a decoupled sector at the black hole horizon which must solve generalised Stokes equations for a charged fluid. By solving these equations we can obtain the DC conductivity of the dual field theory. For Q-lattices and one-dimensional lattices we solve the fluid equations to obtain closed form expressions for the DC conductivity in terms of the solution at the black hole horizon. We also determine the leading order DC conductivity for lattices that can be expanded as a perturbative series about translationally invariant solutions.

  3. Magnetism and transport properties of epitaxial Fe-Ga thin films on GaAs(001)

    SciTech Connect (OSTI)

    Duong Anh Tuan; Shin, Yooleemi; Cho, Sunglae; Dang Duc Dung; Vo Thanh Son

    2012-04-01

    Epitaxial Fe-Ga thin films in disordered bcc {alpha}-Fe crystal structure (A2) have been grown on GaAs(001) by molecular beam epitaxy. The saturated magnetization (M{sub S}) decreased from 1371 to 1105 kA/m with increasing Ga concentration from 10.5 to 24.3 % at room temperature. The lattice parameter increased with the increase in Ga content because of the larger atomic radius of Ga atom than that of Fe. The increase in carrier density with Ga content caused in lower resistivity.

  4. Graphene induced remote surface scattering in graphene/AlGaN/GaN heterostructures

    SciTech Connect (OSTI)

    Liu, Xiwen; Li, Dan; Wang, Bobo; Liu, Bin; Chen, Famin; Jin, Guangri; Lu, Yanwu, E-mail: ywlu@bjtu.edu.cn [Department of Physics, Beijing Jiaotong University, Beijing 100044 (China)

    2014-10-20

    The mobilities of single-layer graphene combined with AlGaN/GaN heterostructures on two-dimensional electron gases in graphene/AlGaN/GaN double heterojunction are calculated. The impact of electron density in single-layer graphene is also studied. Remote surface roughness (RSR) and remote interfacial charge (RIC) scatterings are introduced into this heterostructure. The mobilities limited by RSR and RIC are an order of magnitude higher than that of interface roughness and misfit dislocation. This study contributes to designing structures for generation of higher electron mobility in graphene/AlGaN/GaN double heterojunction.

  5. A Multiphase, Modular, Bidirectional, Triple-Voltage DC-DC Converter Power Systems

    SciTech Connect (OSTI)

    Su, Gui-Jia [ORNL; Tang, Lixin [ORNL

    2008-01-01

    Electrical power systems in future hybrid and fuel cell vehicles may employ three voltage [14 V, 42 V, and high voltage (HV)] nets. These will be necessary to accommodate existing 14-V loads as well as efficiently handle new heavy loads at the 42-V net and a traction drive on the HV bus. A low-cost DC-DC converter was proposed for connecting the three voltage nets. It minimizes the number of switches and their associated gate driver components by using two half-bridges and a high-frequency transformer. Another salient feature is that the half bridge on the 42-V bus is also utilized to provide the 14-V bus by operating at duty ratios around an atypical value of 1/3. Moreover, it makes use of the parasitic capacitance of the switches and the transformer leakage inductance for soft switching. The use of half bridges makes the topology well suited for interleaved multiphase modular configurations as a means to increase the power level because the capacitor legs can be shared. This paper presents simulation and experimental results on an interleaved two-phase arrangement rated at 4.5 kW. Also discussed are the benefits of operating with an atypical duty ratio on the transformer and a preferred multiphase configuration to minimize capacitor ripple currents.

  6. Aalborg Universitet Power flow analysis for droop controlled LV hybrid AC-DC microgrids with virtual

    E-Print Network [OSTI]

    Vasquez, Juan Carlos

    Aalborg Universitet Power flow analysis for droop controlled LV hybrid AC-DC microgrids controlled LV hybrid AC-DC microgrids with virtual impedance. In Proceedings of the IEEE Power & Energy Interlinking converter PV WT IBS DC microgrid DC microgrid AC microgrid AC Load Figure 1. Structure

  7. Switching power converter Figure 1(a): Switching DC-DC converter with analog voltage-mode control

    E-Print Network [OSTI]

    + ­ RC L Vg 1 2 i + v _ Vref + _ Gc(s) VM = 1 PWM u c Switching power converter H v dTs H = 1 design of digital compensators. I. INTRODUCTION Discrete-time modeling of dc-dc switching converters has IEEE. #12;+ ­ R C L Vg 1 2 i + v _ Vref + _ Gc(z) VM = 1 DPWM u c Switching power converter H v dTs H

  8. A High Efficiency DC-DC Converter Topology Suitable for Distributed Large Commercial and Utility Scale PV Systems

    SciTech Connect (OSTI)

    Mohammed S. Agamy; Maja Harfman-Todorovic; Ahmed Elasser; Robert L. Steigerwald; Juan A. Sabate; Song Chi; Adam J. McCann; Li Zhang; Frank Mueller

    2012-09-01

    In this paper a DC-DC power converter for distributed photovoltaic plant architectures is presented. The proposed converter has the advantages of simplicity, high efficiency, and low cost. High efficiency is achieved by having a portion of the input PV power directly fed forward to the output without being processed by the converter. The operation of this converter also allows for a simplified maximum power point tracker design using fewer measurements

  9. AlGaAsSb/GaSb Distributed Bragg Reflectors Grown by Organometallic Vapor Phase Epitaxy

    SciTech Connect (OSTI)

    C.A. Wang; C.J. Vineis; D.R. Calawa

    2002-02-13

    The first AlGaAsSb/GaSb quarter-wave distributed Bragg reflectors grown by metallic vapor phase epitaxy are reported. The peak reflectance is 96% for a 10-period structure.

  10. Impact of electrochemical process on the degradation mechanisms of AlGaN/GaN HEMTs

    E-Print Network [OSTI]

    Gao, Feng, Ph. D. Massachusetts Institute of Technology

    2014-01-01

    AlGaN/GaN high electron mobility transistors (HEMTs) constitute a new generation of transistors with excellent electrical characteristics and great potential to replace silicon technology in the future, especially in high ...

  11. GaN nanowires show more 3D piezoelectricity than bulk GaN

    E-Print Network [OSTI]

    Espinosa, Horacio D.

    director cds murder nudity soundtrack BBC movie releases footage worth documentary film Blu-rays Blu-ray Ga

  12. GaInP/GaAs/GaInAs Monolithic Tandem Cells for High-Performance Solar Concentrators

    SciTech Connect (OSTI)

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

    2005-08-01

    We present a new approach for ultra-high-performance tandem solar cells that involves inverted epitaxial growth and ultra-thin device processing. The additional degree of freedom afforded by the inverted design allows the monolithic integration of high-, and medium-bandgap, lattice-matched (LM) subcell materials with lower-bandgap, lattice-mismatched (LMM) materials in a tandem structure through the use of transparent compositionally graded layers. The current work concerns an inverted, series-connected, triple-bandgap, GaInP (LM, 1.87 eV)/GaAs (LM, 1.42 eV)/GaInAs (LMM, {approx}1 eV) device structure grown on a GaAs substrate. Ultra-thin tandem devices are fabricated by mounting the epiwafers to pre-metallized Si wafer handles and selectively removing the parent GaAs substrate. The resulting handle-mounted, ultra-thin tandem cells have a number of important advantages, including improved performance and potential reclamation/reuse of the parent substrate for epitaxial growth. Additionally, realistic performance modeling calculations suggest that terrestrial concentrator efficiencies in the range of 40-45% are possible with this new tandem cell approach. A laboratory-scale (0.24 cm2), prototype GaInP/GaAs/GaInAs tandem cell with a terrestrial concentrator efficiency of 37.9% at a low concentration ratio (10.1 suns) is described, which surpasses the previous world efficiency record of 37.3%.

  13. Spontaneous emission in GaN/InGaN photonic crystal nanopillars

    E-Print Network [OSTI]

    Boyer, Edmond

    . Sigalas, "InGaN/GaN quantum-well heterostructure light-emitting diodes employing photonic crystal, "III-nitride blue and ultraviolet photonic crystal light emitting diodes," Appl. Phys. Lett. 84, 466, and H. Benisty, "Photonic-crystal GaN light-emitting diodes with tailored guided modes distribution

  14. Switchable piezoelectric transduction in AlGaN/GaN MEMS resonators

    E-Print Network [OSTI]

    Weinstein, Dana

    This work presents a new switching mechanism in piezoelectric transduction of AlGaN/GaN bulk acoustic resonators. A piezoelectric transducer is formed in the AlGaN, between a top Schottky electrode and a 2D electron gas ...

  15. Scientific Achievement Networks of highly photoresponsive crystalline GaSe

    E-Print Network [OSTI]

    Geohegan, David B.

    Scientific Achievement Networks of highly photoresponsive crystalline GaSe nanosheets a crystalline GaSe target was adjusted to directly grow networks of interconnected triangular GaSe crystalline nanosheets of ~ 200 nm size (inset shows atomic

  16. Materials with low DC magnetic susceptibility for sensitive magnetic measurements

    E-Print Network [OSTI]

    Khatiwada, Rakshya; Kendrick, Rachel; Khosravi, Marjan; Peters, Michael; Smith, Erick; Snow, Mike

    2015-01-01

    Materials with very low DC magnetic susceptibility have many scientific applications. To our knowledge however, relatively little research has been conducted with the goal to produce a totally nonmagnetic material. This phrase in our case means after spatially averaging over macroscopic volumes, it possesses an average zero DC magnetic susceptibility. We report measurements of the DC magnetic susceptibility of three different types of nonmagnetic materials at room temperature: (I) solutions of paramagnetic salts and diamagnetic liquids, (II) liquid gallium-indium alloys and (III) pressed powder mixtures of tungsten and bismuth. The lowest measured magnetic susceptibility among these candidate materials is in the order of 10^-9 cgs volume susceptibility units, about two orders of magnitude smaller than distilled water. In all cases, the measured concentration dependence of the magnetic susceptibility is consistent with that expected for the weighted sum of the susceptibilities of the separate components within...

  17. Nuclear magnetic resonance experiments with dc SQUID amplifiers

    SciTech Connect (OSTI)

    Heaney, M.B. . Dept. of Physics Lawrence Berkeley Lab., CA )

    1990-11-01

    The development and fabrication of dc SQUIDs (Superconducting QUantum Interference Devices) with Nb/Al{sub 2}O{sub 3}/Nb Josephson junctions is described. A theory of the dc SQUID as a radio-frequency amplifier is presented, with an optimization strategy that accounts for the loading and noise contributions of the postamplifier and maximizes the signal-to-noise ratio of the total system. The high sensitivity of the dc SQUID is extended to high field NMR. A dc SQUID is used as a tuned radio-frequency amplifier to detect pulsed nuclear magnetic resonance at 32 MHz from a metal film in a 3.5 Tesla static field. A total system noise temperature of 11 K has been achieved, at a bath temperature of 4.2 K. The minimum number of nuclear Bohr magnetons observable from a free precession signal after a single pulse is about 2 {times} 10{sup 17} in a bandwidth of 25 kHz. In a separate experiment, a dc SQUID is used as a rf amplifier in a NQR experiment to observe a new resonance response mechanism. The net electric polarization of a NaClO{sub 3} crystal due to the precessing electric quadrupole moments of the Cl nuclei is detected at 30 MHz. The sensitivity of NMR and NQR spectrometers using dc SQUID amplifiers is compared to the sensitivity of spectrometers using conventional rf amplifiers. A SQUID-based spectrometer has a voltage sensitivity which is comparable to the best achieved by a FET-based spectrometer, at these temperatures and operating frequencies.

  18. Graphite electrode DC arc furnace. Innovative technology summary report

    SciTech Connect (OSTI)

    1999-05-01

    The Graphite Electrode DC Arc Furnace (DC Arc) is a high-temperature thermal process, which has been adapted from a commercial technology, for the treatment of mixed waste. A DC Arc Furnace heats waste to a temperature such that the waste is converted into a molten form that cools into a stable glassy and/or crystalline waste form. Hazardous organics are destroyed through combustion or pyrolysis during the process and the majority of the hazardous metals and radioactive components are incorporated in the molten phase. The DC Arc Furnace chamber temperature is approximately 593--704 C and melt temperatures are as high as 1,500 C. The DC Arc system has an air pollution control system (APCS) to remove particulate and volatiles from the offgas. The advantage of the DC Arc is that it is a single, high-temperature thermal process that minimizes the need for multiple treatment systems and for extensive sorting/segregating of large volumes of waste. The DC Arc has the potential to treat a wide range of wastes, minimize the need for sorting, reduce the final waste volumes, produce a leach resistant waste form, and destroy organic contaminants. Although the DC arc plasma furnace exhibits great promise for treating the types of mixed waste that are commonly present at many DOE sites, several data and technology deficiencies were identified by the Mixed Waste Focus Area (MWFA) regarding this thermal waste processing technique. The technology deficiencies that have been addressed by the current studies include: establishing the partitioning behavior of radionuclides, surrogates, and hazardous metals among the product streams (metal, slag, and offgas) as a function of operating parameters, including melt temperature, plenum atmosphere, organic loading, chloride concentration, and particle size; demonstrating the efficacy of waste product removal systems for slag and metal phases; determining component durability through test runs of extended duration, evaluating the effect of feed composition variations on process operating conditions and slag product performance; and collecting mass balance and operating data to support equipment and instrument design.

  19. Enhanced excitonic photoconductivity due to built-in internal electric field in TlGaSe{sub 2} layered semiconductor

    SciTech Connect (OSTI)

    Seyidov, MirHasan Yu. Suleymanov, Rauf A.; ?ale, Yasin; Balaban, Ertan

    2014-12-07

    The strong enhancement, by several orders of magnitude, of the excitonic peak within the photoconductivity spectrum of TlGaSe{sub 2} semiconductor was observed. The samples were polarized in external dc electric field, which was applied prior to the measurements. Due to the accumulation of charges near the surface, an internal electric field was formed. Electron-hole pairs that were created after the absorption of light are fallen in and then separated by the built-in electric field, which prevents radiative recombination process.

  20. Inductorless DC-AC Cascaded H-bridge Multilevel Boost Inverter for Electric/Hybrid Electric Vehicle

    E-Print Network [OSTI]

    Tolbert, Leon M.

    - DC boost converter to boost the battery voltage for a traditional 3-phase inverter. The present HEV continuous power rating. Currently available power inverter systems for HEVs use a DC-DC boost converter power, the DC-DC boost converter is not needed and the battery voltage will be directly applied

  1. Characterization of the PvdS-regulated promoter motif in Pseudomonas syringae pv. tomato DC3000 reveals

    E-Print Network [OSTI]

    Myers, Chris

    Characterization of the PvdS-regulated promoter motif in Pseudomonas syringae pv. tomato DC3000S, a group IV sigma factor encoded by Pseudomonas syringae pv. tomato DC3000 (DC3000), a plant pathogen, 2002; Potvin et al., 2008). The model plant pathogen Pseudomonas syringae pv. tomato DC3000 (DC3000

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

    DOE Patents [OSTI]

    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.

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

    DOE Patents [OSTI]

    Shimer, Daniel W. (Danville, CA); Lange, Arnold C. (Livermore, CA)

    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.

  4. Development of metallization for GaAs and AlGaAs concentrator solar cells

    SciTech Connect (OSTI)

    Tobin, S.P.

    1987-04-01

    A three-layer metallization system was developed for high temperature stability on GaAs and AlGaAs solar cells. The layers are a Pt ohmic contact metal that forms thermally stable compounds with GaAs, a TiN diffusion barrier, and a gold conductor. The solar cell structure was also designed for contact stability, with the key component being a heavily doped GaAs cap layer. Reactively sputtered TiN was found to act as an excellent barrier when deposited under the proper conditions. The conditions were carefully optimized for low resistivity and low stress in the films. A low but nonzero substrate bias during sputtering was found to be important. Solar cells with sputtered metallizations of Pt/TiN/Ti/Pt/Au were found to be thermally stable up to 500/sup 0/C for 15 minutes in vacuum. At 600/sup 0/C there was catastrophic degradation of the cells due to dissociation of uncapped GaAs surfaces. Below this temperature the metallization performed as designed. The Pt and GaAs layers reacted to form a stable PtGa compound layer that gave low contact resistance. There was no penetration of Au or GaAs through the barrier layer. These results are a very encouraging first step leading to stable, reliable GaAs and AlGaAs concentrator cells.

  5. Quantum efficiency temporal response and lifetime of a GaAs cathode in SRF electron gun

    SciTech Connect (OSTI)

    Wang, E.; Ben-Zvi, I.; Kewisch, J.; Burrill, A.; Rao, T.; Wu, Q.; Holmes, D.

    2010-05-23

    RF electron guns with a strained super lattice GaAs cathode can generate polarized electron beam of higher brightness and lower emittance than do DC guns, due to their higher field gradient at the cathode's surface. In a normal conducting RF gun, the extremely high vaccum required by these cathodes can not be met. We report on an experiment with a superconducting SRF gun, which can maintain a vacuum of nearly 10-12 torr because of cryo-pumping at the temperature of 4.2K. With conventional activation, we obtained a QE of 3% at 532 nm, with lifetime of nearly 3 days in the preparation chamber. We plan to use this cathode in a 1.3 GHz 1/2 cell SRF gun to study its performance. In addition, we studied the multipacting at the location of cathode. A new model based on the Forkker-Planck equation which can estimate the bunch length of the electron beam is discussed in this paper. Future particle accelerators such as eRHIC and ILC require high brightness, high current polarized electrons Recently, using a superlattice crystal, the maximum polarization of 95% was reached. Activation with Cs,O lowers the electron affinity and makes it energetically possible for all the electrons excited in to the conduction band and reach the surface to escape into the vacuum. Presently the polarized electron sources are based on DC gun, such as that at the CEBAF at Jlab. In these devices, the life time of the cathode is extended due to the reduced back bombardment in their UHV conditions. However, the low accelerating gradient of the DC guns lead to poor longitudinal emittance. The higher accelerating gradient of the RF gun generates low emittance beams. Superconducting RF guns combine the excellent vacuum conditions of the DC guns with the higher accelerating gradients of the RF guns and provide potentially a long lived cathode with very low transverse and longitudinal emittance. In our work at BNL, we successfully activated the GaAs. The quantum efficient is 3% at 532 nm and is expected to improve further. In addition, we studied the multipacting at the location of cathode. A new model based on the Forkker-Planck equation which can estimate the bunch length of the electron beam is discussed in this paper.

  6. Effect of temperature on the current (capacitance and conductance)–voltage characteristics of Ti/n-GaAs diode

    SciTech Connect (OSTI)

    Ejderha, K.; Duman, S. Urhan, F.; Nuhoglu, C.; Turut, A.

    2014-12-21

    In this study, Ti/n-GaAs Schottky barrier diode has been fabricated by DC magnetron sputtering. The current–voltage, capacitance–voltage, and conductance–voltage characteristics of Ti/n–GaAs diode have been investigated in the temperature range of 80–320?K. The ideality factor and barrier height values have been calculated from the forward current–voltage characteristics. The variation of the diode parameters with the sample temperature has been attributed to the presence of the lateral inhomogeneities of the barrier height. The temperature dependent capacitance–voltage characteristics have been measured to calculate the carrier concentration, diffusion potential, barrier height, and temperature coefficient of the barrier height (??=??0.65?meV K{sup ?1}). The fact that the temperature coefficient of the barrier height changes from metal to metal has been ascribed to the chemical nature of the contact metal or metal electronegativity.

  7. Efficient Switches for Solar Power Conversion: Four Quadrant GaN Switch Enabled Three Phase Grid-Tied Microinverters

    SciTech Connect (OSTI)

    2012-02-13

    Solar ADEPT Project: Transphorm is developing power switches for new types of inverters that improve the efficiency and reliability of converting energy from solar panels into useable electricity for the grid. Transistors act as fast switches and control the electrical energy that flows in an electrical circuit. Turning a transistor off opens the circuit and stops the flow of electrical current; turning it on closes the circuit and allows electrical current to flow. In this way a transistor can be used to convert DC from a solar panel into AC for use in a home. Transphorm’s transistors will enable a single semiconductor device to switch electrical currents at high-voltage in both directions—making the inverter more compact and reliable. Transphorm is using Gallium Nitride (GaN) as a semiconductor material in its transistors instead of silicon, which is used in most conventional transistors, because GaN transistors have lower losses at higher voltages and switching frequencies.

  8. Method for manufacturing compound semiconductor field-effect transistors with improved DC and high frequency performance

    DOE Patents [OSTI]

    Zolper, John C. (Vienna, VA); Sherwin, Marc E. (Rockville, MD); Baca, Albert G. (Albuquerque, NM)

    2000-01-01

    A method for making compound semiconductor devices including the use of a p-type dopant is disclosed wherein the dopant is co-implanted with an n-type donor species at the time the n-channel is formed and a single anneal at moderate temperature is then performed. Also disclosed are devices manufactured using the method. In the preferred embodiment n-MESFETs and other similar field effect transistor devices are manufactured using C ions co-implanted with Si atoms in GaAs to form an n-channel. C exhibits a unique characteristic in the context of the invention in that it exhibits a low activation efficiency (typically, 50% or less) as a p-type dopant, and consequently, it acts to sharpen the Si n-channel by compensating Si donors in the region of the Si-channel tail, but does not contribute substantially to the acceptor concentration in the buried p region. As a result, the invention provides for improved field effect semiconductor and related devices with enhancement of both DC and high-frequency performance.

  9. Structural and optical properties of InGaN–GaN nanowire heterostructures grown by molecular beam epitaxy

    SciTech Connect (OSTI)

    Limbach, F.; Gotschke, T.; Stoica, T.; Calarco, R.; Sutter, E.; Ciston, J.; Cusco, R.; Artus, L.; Kremling, S.; Ho?fling, S.; Worschech, L.; Gru?tzmacher, D.

    2011-01-01

    InGaN/GaN nanowire (NW) heterostructures grown by plasma assisted molecular beam epitaxy were studied in comparison to their GaN and InGaN counterparts. The InGaN/GaN heterostructure NWs are composed of a GaN NW, a thin InGaN shell, and a multifaceted InGaN cap wrapping the top part of the GaN NW. High-resolution transmission electron microscopy (HRTEM) images taken from different parts of a InGaN/GaN NW show a wurtzite structure of the GaN core and the epitaxial InGaN shell around it, while additional crystallographic domains are observed whithin the InGaN cap region. Large changes in the lattice parameter along the wire, from pure GaN to higher In concentration demonstrate the successful growth of a complex InGaN/GaN NW heterostructure. Photoluminescence (PL) spectra of these heterostructure NW ensembles show rather broad and intense emission peak at 2.1 eV. However, ?-PL spectra measured on single NWs reveal a reduced broadening of the visible luminescence. The analysis of the longitudinal optical phonon Raman peak position and its shape reveal a variation in the In content between 20% and 30%, in agreement with the values estimated by PL and HRTEM investigations. The reported studies are important for understanding of the growth and properties of NW heterostructures suitable for applications in optoelectronics and photovoltaics.

  10. Gate-control efficiency and interface state density evaluated from capacitance-frequency-temperature mapping for GaN-based metal-insulator-semiconductor devices

    SciTech Connect (OSTI)

    Shih, Hong-An; Kudo, Masahiro; Suzuki, Toshi-kazu

    2014-11-14

    We present an analysis method for GaN-based metal-insulator-semiconductor (MIS) devices by using capacitance-frequency-temperature (C-f-T) mapping to evaluate the gate-control efficiency and the interface state density, both exhibiting correlations with the linear-region intrinsic transconductance. The effectiveness of the method was exemplified by application to AlN/AlGaN/GaN MIS devices to elucidate the properties of AlN-AlGaN interfaces depending on their formation processes. Using the C-f-T mapping, we extract the gate-bias-dependent activation energy with its derivative giving the gate-control efficiency, from which we evaluate the AlN-AlGaN interface state density through the Lehovec equivalent circuit in the DC limit. It is shown that the gate-control efficiency and the interface state density have correlations with the linear-region intrinsic transconductance, all depending on the interface formation processes. In addition, we give characterization of the AlN-AlGaN interfaces by using X-ray photoelectron spectroscopy, in relation with the results of the analysis.

  11. D.C. Water Resource Research Center Annual Technical Report

    E-Print Network [OSTI]

    strengthening a credible program. Proposals submitted to USGS for the 2002 fiscal year was approved and funding to the success of the Institute. Hence, the goals of 2002 fiscal year will continue to fiscal 2003 while DC water resources information has been significantly delayed because UDC website, which hosts WRRI

  12. DC WRRC Report No. 59 DEVELOPMENT OF FREQUENCY

    E-Print Network [OSTI]

    District of Columbia, University of the

    #12;DC WRRC Report No. 59 DEVELOPMENT OF FREQUENCY FUNCTIONS FOR URBAN NON-POINT SOURCE RISK THE CATHOLIC UNIVERSITY OF AMERICA "This work on which this report is based was supported in part by funds guidance during the entire course of the work. Ms. Cathy Saunders served as research assistant

  13. DC WRRC Report No. 139 BOOK OF ABSTRACTS

    E-Print Network [OSTI]

    District of Columbia, University of the

    Washington, DC 20008 , (202) 274- 6400 #12;Table of Contents Preface i I. Social Sciences 1 II. Ground Water THE FEDERAL WATER POLLUTION CONTROL ACT AMENDMENTS OF 1972 Lieber, H. WRRC Report No. 17 DESCRWWRS: Management 208 of the Clean Water Act was examined. The accomplishments and failures of the 208 plans were

  14. Natural Gas Pipeline Leaks Across Washington, DC Robert B. Jackson,,,

    E-Print Network [OSTI]

    Jackson, Robert B.

    Natural Gas Pipeline Leaks Across Washington, DC Robert B. Jackson,,, * Adrian Down, Nathan G increased in recent decades, but incidents involving natural gas pipelines still cause an average of 17 fatalities and $133 M in property damage annually. Natural gas leaks are also the largest anthropogenic

  15. Winter Break Trip 2014 New York City & Washington DC

    E-Print Network [OSTI]

    Hutcheon, James M.

    Winter Break Trip 2014 New York City & Washington DC Tentative Trip Information December 13/Meadowlands 575 Park Plaza Drive Secaucus, NJ 07094 (201) 422-9480 Hotel is located 3 miles west of New York City for departure at 5pm. · Public Transportation to and from the city o Bus stop is at NW E ST & NW New Jersey Ave

  16. HYBRID DC ACCURATE CHARGE AMPLIFIER FOR LINEAR PIEZOELECTRIC POSITIONING

    E-Print Network [OSTI]

    Fleming, Andrew J.

    the diverse literature in- volving piezoelectric applications is the problem of hysteresis (Adriaens et alHYBRID DC ACCURATE CHARGE AMPLIFIER FOR LINEAR PIEZOELECTRIC POSITIONING Andrew J. Fleming, S. O, Australia 2308 Abstract: Piezoelectric transducers are known to exhibit less hysterisis when driven

  17. DC WRRC Report No. 170 Program ReportAnnual

    E-Print Network [OSTI]

    District of Columbia, University of the

    the people living in the north east of Washington, D.C. and measured the degree of their interest products constitute their endorsement by the United States Government. #12;The project entitled "A Pilot of groundwater inflows requires a knowledge of the hydraulic conductivity or permeability of the sediments

  18. Qualifying Exam Presentation: DC Discharge Studies Using PIC-MCC

    E-Print Network [OSTI]

    Wurtele, Jonathan

    Qualifying Exam Presentation: DC Discharge Studies Using PIC-MCC Jeffrey Hammel Department during cylindrical magnetron sputtering To assess the applicability of the PIC-MCC method for modeling;Presentation Overview I. Introduction II. Theory A. Paschen's Law B. Positive Column III. PIC-MCC Simulations A

  19. D.C. Water Resources Research Center Annual Technical Report

    E-Print Network [OSTI]

    of DC municipal drinking water quality through random sampling and testing of residential homes that could literally transform the lives of people, especially in the area of water availability. Mr. David. The Institute and the Cooperative Extension Service also added a solar powered weather station to the site

  20. Fuzzy Estimation of DC Motor Winding Currents Innovatia Software

    E-Print Network [OSTI]

    Simon, Dan

    Fuzzy Estimation of DC Motor Winding Currents Dan Simon Innovatia Software 775 Rothrock Circle °ux is rotated in the desired direction of ofuzzy ¯ltering to motor winding current estimation stator windings. an attractive alternative to current estimation using In order to implement an e

  1. Ohmic contacts to n-GaSb 

    E-Print Network [OSTI]

    Yang, Zhengchong

    1997-01-01

    In recent years, the Ill-V semiconductor GaSb and its ternary alloys containing antimony have exhibited interesting electrical and optical properties for device applications which include negative resistance tunnel devices, lasers, detectors and FET...

  2. GaTe semiconductor for radiation detection

    DOE Patents [OSTI]

    Payne, Stephen A. (Castro Valley, CA); Burger, Arnold (Nashville, TN); Mandal, Krishna C. (Ashland, MA)

    2009-06-23

    GaTe semiconductor is used as a room-temperature radiation detector. GaTe has useful properties for radiation detectors: ideal bandgap, favorable mobilities, low melting point (no evaporation), non-hygroscopic nature, and availability of high-purity starting materials. The detector can be used, e.g., for detection of illicit nuclear weapons and radiological dispersed devices at ports of entry, in cities, and off shore and for determination of medical isotopes present in a patient.

  3. DC powerline communication system using a transmission line transformer for high degree of freedom applications

    E-Print Network [OSTI]

    Wade, Eric R. (Eric Randolph), 1978-

    2004-01-01

    A new type of powerline communication is developed to reduce cable requirements for robotic, electromechanical, and vehicular systems. A DC power bus line connecting a DC power supply to motor drives and sensor units is ...

  4. If you reside in WASHINGTON, DC - MD -VA - WV your salary will...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    If you are employed in the WASHINGTON, DC Metropolitan Area (D.C., Baltimore, Northern VA, Eastern WV, and Southern PA) your salary will range from: Pay Band Pay Plan(s) Minimum...

  5. Energy Secretary Moniz's Remarks at CSIS in Washington D.C. on...

    Energy Savers [EERE]

    Moniz's Remarks at CSIS in Washington D.C. on Energy Security 40 Years after the Embargo - As Delivered Energy Secretary Moniz's Remarks at CSIS in Washington D.C. on Energy...

  6. D.C. Middle and High School Students Get a Chance to Experience...

    Energy Savers [EERE]

    D.C. Middle and High School Students Get a Chance to Experience the Regional Science Bowl Competition Setting D.C. Middle and High School Students Get a Chance to Experience the...

  7. Recovery Act: Integrated DC-DC Conversion for Energy-Efficient Multicore Processors

    SciTech Connect (OSTI)

    Shepard, Kenneth L

    2013-03-31

    In this project, we have developed the use of thin-film magnetic materials to improve in energy efficiency of digital computing applications by enabling integrated dc-dc power conversion and management with on-chip power inductors. Integrated voltage regulators also enables fine-grained power management, by providing dynamic scaling of the supply voltage in concert with the clock frequency of synchronous logic to throttle power consumption at periods of low computational demand. The voltage converter generates lower output voltages during periods of low computational performance requirements and higher output voltages during periods of high computational performance requirements. Implementation of integrated power conversion requires high-capacity energy storage devices, which are generally not available in traditional semiconductor processes. We achieve this with integration of thin-film magnetic materials into a conventional complementary metal-oxide-semiconductor (CMOS) process for high-quality on-chip power inductors. This project includes a body of work conducted to develop integrated switch-mode voltage regulators with thin-film magnetic power inductors. Soft-magnetic materials and inductor topologies are selected and optimized, with intent to maximize efficiency and current density of the integrated regulators. A custom integrated circuit (IC) is designed and fabricated in 45-nm CMOS silicon-on-insulator (SOI) to provide the control system and power-train necessary to drive the power inductors, in addition to providing a digital load for the converter. A silicon interposer is designed and fabricated in collaboration with IBM Research to integrate custom power inductors by chip stacking with the 45-nm CMOS integrated circuit, enabling power conversion with current density greater than 10A/mm2. The concepts and designs developed from this work enable significant improvements in performance-per-watt of future microprocessors in servers, desktops, and mobile devices. These new approaches to scaled voltage regulation for computing devices also promise significant impact on electricity consumption in the United States and abroad by improving the efficiency of all computational platforms. In 2006, servers and datacenters in the United States consumed an estimated 61 billion kWh or about 1.5% of the nation's total energy consumption. Federal Government servers and data centers alone accounted for about 10 billion kWh, for a total annual energy cost of about $450 million. Based upon market growth and efficiency trends, estimates place current server and datacenter power consumption at nearly 85 billion kWh in the US and at almost 280 billion kWh worldwide. Similar estimates place national desktop, mobile and portable computing at 80 billion kWh combined. While national electricity utilization for computation amounts to only 4% of current usage, it is growing at a rate of about 10% a year with volume servers representing one of the largest growth segments due to the increasing utilization of cloud-based services. The percentage of power that is consumed by the processor in a server varies but can be as much as 30% of the total power utilization, with an additional 50% associated with heat removal. The approaches considered here should allow energy efficiency gains as high as 30% in processors for all computing platforms, from high-end servers to smart phones, resulting in a direct annual energy savings of almost 15 billion kWh nationally, and 50 billion kWh globally. The work developed here is being commercialized by the start-up venture, Ferric Semiconductor, which has already secured two Phase I SBIR grants to bring these technologies to the marketplace.

  8. Fig.1: Digital Controller with modified buck-boost converter LOAD-INTERACTIVE STEERED-INDUCTOR DC-DC

    E-Print Network [OSTI]

    Prodiæ, Aleksandar

    Fig.1: Digital Controller with modified buck-boost converter LOAD-INTERACTIVE STEERED-INDUCTOR DC-inverting buck- boost. Transient response results show that, compared to standard converters with near-inverting buck-boost converter, i.e. steered-inductor buck-boost, a digital controller, and a communication block

  9. Building Scale DC Microgrids Chris Marnay, Steven Lanzisera, Michael Stadler, and Judy Lai

    E-Print Network [OSTI]

    of building loads are either native DC, such as electronics and compact fluorescent and light emitting diode

  10. Potential Federal On-Site Solar Aggregation in Washington, D.C., and Maryland

    Broader source: Energy.gov [DOE]

    Presentation describes potential Federal on-site solar aggregation opportunities in Washington, D.C., and Maryland.

  11. Interviews in Washington, DC for Albert Einstein Fellowship Semi-Finalists

    Broader source: Energy.gov [DOE]

    Selected semi-finalists in the Albert Einstein Distinguished Educator Fellowship are invited to DC for interviews.

  12. Demonstration of LED Retrofit Lamps at the Smithsonian Art Museum, Washington, DC

    SciTech Connect (OSTI)

    Miller, N. J.; Rosenfeld, S. M.

    2012-06-01

    GATEWAY program report on a demonstration of LED retrofit lamps at the Smithsonian American Art Museum in Washington, DC.

  13. Sputter target erosion and its effects on long duration DC magnetron sputter coating

    E-Print Network [OSTI]

    Schoff, Michael Elliott

    2009-01-01

    Duration DC Magnetron Sputter Coating A thesis submitted in1 II. Sputter Coating24 VII. Coating Rate vs.

  14. A nonlinear robust HVDC control for a parallel AC/DC power system

    E-Print Network [OSTI]

    Qu, Zhihua

    recognized that, through an HVDC transmission line, fast electronic control can be applied on the DC power, controlling DC line transmission power can improve stability of the AC system after a major disturbanceA nonlinear robust HVDC control for a parallel AC/DC power system Hongzhi Cai a , Zhihua Qu b

  15. Towards Building an Optimal Demand Response Framework for DC Distribution Networks

    E-Print Network [OSTI]

    Mohsenian-Rad, Hamed

    Towards Building an Optimal Demand Response Framework for DC Distribution Networks Hamed Mohsenian, an optimization-based foundation is proposed for demand response in DC distribution networks in presence to assess the performance and to gain insights into the proposed demand-response paradigm. Keywords: DC

  16. Aalborg Universitet Generation-Side Power Scheduling in a Grid-Connected DC Microgrid

    E-Print Network [OSTI]

    Vasquez, Juan Carlos

    Aalborg Universitet Generation-Side Power Scheduling in a Grid-Connected DC Microgrid Hernández). Generation-Side Power Scheduling in a Grid-Connected DC Microgrid. In IEEE ICDCM 2015. IEEE. General rights.aau.dk on: juli 04, 2015 #12;Generation-Side Power Scheduling in a Grid-Connected DC Microgrid Adriana C

  17. Aalborg Universitet Modeling, Stability Analysis and Active Stabilization of Multiple DC-Microgrids Clusters

    E-Print Network [OSTI]

    Vasquez, Juan Carlos

    Aalborg Universitet Modeling, Stability Analysis and Active Stabilization of Multiple DC-Microgrids and Active Stabilization of Multiple DC-Microgrids Clusters. In Proceedings of the 2014 IEEE International of Multiple DC-Microgrid Clusters," in Proc. IEEE International Energy Conference (EnergyCon'14), 2014

  18. Aalborg Universitet Agent-based distributed hierarchical control of dc microgrid systems

    E-Print Network [OSTI]

    Vasquez, Juan Carlos

    Aalborg Universitet Agent-based distributed hierarchical control of dc microgrid systems Meng, J. M., & Dragicevic, T. (2014). Agent-based distributed hierarchical control of dc microgrid systems-BASED DISTRIBUTED HIERARCHICAL CONTROL OF DC MICROGRID SYSTEMS Lexuan Meng, Tomislav Dragicevic, Josep M. Guerrero

  19. OLENDER REPORTING, INC. 1100 Connecticut Avenue NW, #810, Washington, DC 20036

    E-Print Network [OSTI]

    1 OLENDER REPORTING, INC. 1100 Connecticut Avenue NW, #810, Washington, DC 20036 Washington: 202 Avenue17 Washington, D.C.18 19 20 21 22 #12;2 OLENDER REPORTING, INC. 1100 Connecticut Avenue NW, #810 #12;3 OLENDER REPORTING, INC. 1100 Connecticut Avenue NW, #810, Washington, DC 20036 Washington: 202

  20. Control of a Fuel-Cell Powered DC Electric Vehicle Motor

    E-Print Network [OSTI]

    Skogestad, Sigurd

    Control of a Fuel-Cell Powered DC Electric Vehicle Motor Federico Zenith Sigurd Skogestad Meeting, 2005 www.ntnu.no Federico Zenith, Sigurd Skogestad, Control of a Fuel-Cell Powered DC Electric Vehicle Motor #12;2 Outline 1) Control of Fuel Cells--Status 2) Dynamic Modelling of Fuel Cells 3) DC

  1. InGaN/GaN tunnel junctions for hole injection in GaN light emitting diodes

    SciTech Connect (OSTI)

    Krishnamoorthy, Sriram, E-mail: krishnamoorthy.13@osu.edu, E-mail: rajan@ece.osu.edu; Akyol, Fatih [Department of Electrical and Computer Engineering, The Ohio State University, Columbus, Ohio 43210 (United States); Rajan, Siddharth, E-mail: krishnamoorthy.13@osu.edu, E-mail: rajan@ece.osu.edu [Department of Electrical and Computer Engineering, The Ohio State University, Columbus, Ohio 43210 (United States); Department of Materials Science and Engineering, The Ohio State University, Columbus, Ohio 43210 (United States)

    2014-10-06

    InGaN/GaN tunnel junction contacts were grown using plasma assisted molecular beam epitaxy (MBE) on top of a metal-organic chemical vapor deposition (MOCVD)-grown InGaN/GaN blue (450?nm) light emitting diode. A voltage drop of 5.3?V at 100?mA, forward resistance of 2 × 10{sup ?2} ? cm{sup 2}, and a higher light output power compared to the reference light emitting diodes (LED) with semi-transparent p-contacts were measured in the tunnel junction LED (TJLED). A forward resistance of 5?×?10{sup ?4} ? cm{sup 2} was measured in a GaN PN junction with the identical tunnel junction contact as the TJLED, grown completely by MBE. The depletion region due to the impurities at the regrowth interface between the MBE tunnel junction and the MOCVD-grown LED was hence found to limit the forward resistance measured in the TJLED.

  2. Journal of Crystal Growth 298 (2007) 272275 Dislocation analysis in homoepitaxial GaInN/GaN light emitting

    E-Print Network [OSTI]

    Wetzel, Christian M.

    2007-01-01

    of GaInN/GaN-based light emitting diodes (LED) on quasi-bulk GaN with an atomically flat polished were much improved. The optical output power of the light emitting diode increased by more than one. Cathodoluminescence; A1. Threading dislocation density; A2. Homoepitaxial growth; B1. GaInN; B3. Light emitting diode

  3. Thermoelectric effects in wurtzite GaN and AlxGa1-xN alloys and Alexander A. Balandin

    E-Print Network [OSTI]

    Thermoelectric effects in wurtzite GaN and AlxGa1-xN alloys Weili Liua and Alexander A. Balandin have investigated theoretically the thermoelectric effects in wurtzite GaN crystals and AlxGa1-xN-based alloys may have some potential as thermoelectric materials at high temperature. It was found

  4. Ultra-high frequency photoconductivity decay in GaAs/Ge/GaAs double heterostructure grown by molecular beam epitaxy

    SciTech Connect (OSTI)

    Hudait, M. K.; Zhu, Y. [Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia 24061 (United States)] [Bradley Department of Electrical and Computer Engineering, Virginia Tech, Blacksburg, Virginia 24061 (United States); Johnston, S. W. [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States)] [National Renewable Energy Laboratory, Golden, Colorado 80401 (United States); Maurya, D.; Priya, S. [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States)] [Center for Energy Harvesting Materials and Systems (CEHMS), Virginia Tech, Blacksburg, Virginia 24061 (United States); Umbel, R. [Materials Science and Engineering, Virginia Tech, Blacksburg, Virginia 24061 (United States)] [Materials Science and Engineering, Virginia Tech, Blacksburg, Virginia 24061 (United States)

    2013-03-04

    GaAs/Ge/GaAs double heterostructures (DHs) were grown in-situ using two separate molecular beam epitaxy chambers. High-resolution x-ray rocking curve demonstrates a high-quality GaAs/Ge/GaAs heterostructure by observing Pendelloesung oscillations. The kinetics of the carrier recombination in Ge/GaAs DHs were investigated using photoconductivity decay measurements by the incidence excitation from the front and back side of 15 nm GaAs/100 nm Ge/0.5 {mu}m GaAs/(100)GaAs substrate structure. High-minority carrier lifetimes of 1.06-1.17 {mu}s were measured when excited from the front or from the back of the Ge epitaxial layer, suggests equivalent interface quality of GaAs/Ge and Ge/GaAs. Wavelength-dependent minority carrier recombination properties are explained by the wavelength-dependent absorption coefficient of Ge.

  5. Heat load of a P-doped GaAs photocathode in SRF electron gun

    SciTech Connect (OSTI)

    Wang, E.; Ben-Zvi, I.; Kewisch, J.; Burrill, A.; Rao, T.; Wu, Q.; Jain, A.; Gupta, R.; Holmes, D.

    2010-05-23

    Many efforts were made over the last decades to develop a better polarized electron source for the high energy physics. Several laboratories operate DC guns with the Gallium-Arsenide photo-cathode, which yield a highly polarized electron beam. However, the beam's emittance might well be improved using a Superconducting RF electron gun, which delivers beams of higher brightness than DC guns does, because the field gradient at the cathode is higher. SRF guns with metal cathodes and CsTe cathodes have been tested successfully. To produce polarized electrons, a Gallium-Arsenide photo-cathode must be used: an experiment to do so in a superconducting RF gun is under way at BNL. Since the cathode will be normal conducting, the problem about the heat load stemming from the cathode arises. We present our measurements of the electrical resistance of GaAs at cryogenic temperatures, a prediction of the heat load and the verification by measuring the quality factor of the gun with and without cathode.

  6. Green cubic GaInN/GaN light-emitting diode on microstructured silicon (100)

    SciTech Connect (OSTI)

    Stark, Christoph J. M.; Detchprohm, Theeradetch; Wetzel, Christian, E-mail: wetzel@ieee.org [Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States) [Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Future Chips Constellation, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180 (United States); Lee, S. C.; Brueck, S. R. J. [Department of Electrical and Computer Engineering and Center for High Technology Materials, University of New Mexico, 1313 Goddard SE, Albuquerque, New Mexico 87106 (United States)] [Department of Electrical and Computer Engineering and Center for High Technology Materials, University of New Mexico, 1313 Goddard SE, Albuquerque, New Mexico 87106 (United States); Jiang, Y.-B. [Department of Earth and Planetary Science, University of New Mexico, Albuquerque, New Mexico 87131 (United States)] [Department of Earth and Planetary Science, University of New Mexico, Albuquerque, New Mexico 87131 (United States)

    2013-12-02

    GaInN/GaN light-emitting diodes free of piezoelectric polarization were prepared on standard electronic-grade Si(100) substrates. Micro-stripes of GaN and GaInN/GaN quantum wells in the cubic crystal structure were grown on intersecting (111) planes of microscale V-grooved Si in metal-organic vapor phase epitaxy, covering over 50% of the wafer surface area. Crystal phases were identified in electron back-scattering diffraction. A cross-sectional analysis reveals a cubic structure virtually free of line defects. Electroluminescence over 20 to 100??A is found fixed at 487?nm (peak), 516?nm (dominant). Such structures therefore should allow higher efficiency, wavelength-stable light emitters throughout the visible spectrum.

  7. A hole accelerator for InGaN/GaN light-emitting diodes

    SciTech Connect (OSTI)

    Zhang, Zi-Hui; Liu, Wei; Tan, Swee Tiam; Ji, Yun; Wang, Liancheng; Zhu, Binbin; Zhang, Yiping; Lu, Shunpeng; Zhang, Xueliang; Hasanov, Namig; Sun, Xiao Wei, E-mail: EXWSUN@ntu.edu.sg, E-mail: VOLKAN@stanfordalumni.org [LUMINOUS Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, School of Physical and Mathematical Sciences, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Demir, Hilmi Volkan, E-mail: EXWSUN@ntu.edu.sg, E-mail: VOLKAN@stanfordalumni.org [LUMINOUS Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, School of Physical and Mathematical Sciences, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Department of Electrical and Electronics, Department of Physics, and UNAM-Institute of Material Science and Nanotechnology, Bilkent University, TR-06800 Ankara (Turkey)

    2014-10-13

    The quantum efficiency of InGaN/GaN light-emitting diodes (LEDs) has been significantly limited by the insufficient hole injection, and this is caused by the inefficient p-type doping and the low hole mobility. The low hole mobility makes the holes less energetic, which hinders the hole injection into the multiple quantum wells (MQWs) especially when a p-type AlGaN electron blocking layer (EBL) is adopted. In this work, we report a hole accelerator to accelerate the holes so that the holes can obtain adequate kinetic energy, travel across the p-type EBL, and then enter the MQWs more efficiently and smoothly. In addition to the numerical study, the effectiveness of the hole accelerator is experimentally shown through achieving improved optical output power and reduced efficiency droop for the proposed InGaN/GaN LED.

  8. Gallium surface diffusion on GaAs (001) surfaces measured by crystallization dynamics of Ga droplets

    SciTech Connect (OSTI)

    Bietti, Sergio, E-mail: sergio.bietti@mater.unimib.it; Somaschini, Claudio; Esposito, Luca; Sanguinetti, Stefano [L–NESS and Dipartimento di Scienza dei Materiali, Università di Milano Bicocca, Via Cozzi 55, I–20125 Milano (Italy); Fedorov, Alexey [L–NESS and CNR–IFN, via Anzani 42, I-22100 Como (Italy)

    2014-09-21

    We present accurate measurements of Ga cation surface diffusion on GaAs surfaces. The measurement method relies on atomic force microscopy measurement of the morphology of nano–disks that evolve, under group V supply, from nanoscale group III droplets, earlier deposited on the substrate surface. The dependence of the radius of such nano-droplets on crystallization conditions gives direct access to Ga diffusion length. We found an activation energy for Ga on GaAs(001) diffusion E{sub A}=1.31±0.15 eV, a diffusivity prefactor of D?=0.53(×2.1±1) cm² s?¹ that we compare with the values present in literature. The obtained results permit to better understand the fundamental physics governing the motion of group III ad–atoms on III–V crystal surfaces and the fabrication of designable nanostructures.

  9. Proceedings of the 1997 IEEE International Conference on Systems, Man, and Cybernetics (SMC'97) . Orlando, FL . Oct. 1215, 1997 DATA REPRESENTATION AND ORGANIZATION FOR AN INDUSTRIAL MULTISENSOR

    E-Print Network [OSTI]

    Naish, Michael D.

    INTEGRATION ARCHITECTURE Michael D. Naish and Elizabeth A. Croft Industrial Automation Laboratory Department) . Orlando, FL . Oct. 12­15, 1997 DATA REPRESENTATION AND ORGANIZATION FOR AN INDUSTRIAL MULTISENSOR@mech.ubc.ca ABSTRACT An open architecture for intelligent multisensor integra­ tion in an industrial environment

  10. FSU Health Compliance Record fax to 8506448958 or mail to 960 Learning Way, Tallahassee, FL 323064178 Part A--Print or type. Illegible forms will not be processed.

    E-Print Network [OSTI]

    McQuade, D. Tyler

    FSU Health Compliance Record fax to 8506448958 or mail to 960 Learning Way, Tallahassee, FL, at the discre on of health center per sonnel, medical and surgical care including examina ons, treatments to make contact will not prevent emergency treatment if necessary to preserve life or health Signature

  11. ION GNSS+ 2014 Conference, Session D5, Tampa, FL (Sep 8-12, 2014) 1/13 Inter-Sensor Validation for Improved Reliability

    E-Print Network [OSTI]

    Calgary, University of

    , MEMS sensor processing, and statistical signal processing. Dr. Gérard Lachapelle holds a CanadaION GNSS+ 2014 Conference, Session D5, Tampa, FL (Sep 8-12, 2014) 1/13 Inter-Sensor Validation for Improved Reliability of Multi-Sensor Systems Anup Dhital, Gérard Lachapelle, Jared B. Bancroft Position

  12. Zarillo, G. A., and Brehin, F. G. A. 2007. Hydrodynamic and Morphologic Modeling at Sebastian Inlet, FL. Proceedings Coastal Sediments '07 Conference, ASCE Press, Reston,

    E-Print Network [OSTI]

    US Army Corps of Engineers

    Inlet, FL. Proceedings Coastal Sediments '07 Conference, ASCE Press, Reston, VA, 1297-1310. HYDRODYNAMIC Modeling System (CMS) to investigate the morphological response to time varying forcing, sediment texture evolution of tidal inlet shoals is an important management tool, since they control sediment budgets. Inlet

  13. Melting of colloidal crystals: A Monte Carlo study James C. Zahorchak, FL Kesavamoorthy, @vb)Rob D. Coalson, and Sanford A. Asherb)

    E-Print Network [OSTI]

    Asher, Sanford A.

    Melting of colloidal crystals: A Monte Carlo study James C. Zahorchak, FL Kesavamoorthy, @vb)Rob D) Electrostatically stabilized colloidal crystals show phase transitions into liquid and gaslike states as the ionic of four colloidal crystals (two fee crystals and two bee crystals) which have also been examined

  14. Multilevel cascade voltage source inverter with separate DC sources

    DOE Patents [OSTI]

    Peng, F.Z.; Lai, J.S.

    1997-06-24

    A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations. 15 figs.

  15. Multilevel cascade voltage source inverter with seperate DC sources

    DOE Patents [OSTI]

    Peng, Fang Zheng (Oak Ridge, TN); Lai, Jih-Sheng (Knoxville, TN)

    1997-01-01

    A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations.

  16. Multilevel cascade voltage source inverter with seperate DC sources

    DOE Patents [OSTI]

    Peng, Fang Zheng; Lai, Jih-Sheng

    2001-04-03

    A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations.

  17. Multilevel cascade voltage source inverter with seperate DC sources

    DOE Patents [OSTI]

    Peng, Fang Zheng (Knoxville, TN); Lai, Jih-Sheng (Blacksburg, VA)

    2002-01-01

    A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations.

  18. AVTA: Battery Testing- DC Fast Charging's Effects on PEV Batteries

    Broader source: Energy.gov [DOE]

    The Vehicle Technologies Office's Advanced Vehicle Testing Activity carries out testing on a wide range of advanced vehicles and technologies on dynamometers, closed test tracks, and on-the-road. These results provide benchmark data that researchers can use to develop technology models and guide future research and development. The following report describes DC fast charging's effects on plug-in electric vehicle batteries. This research was conducted by Idaho National Laboratory.

  19. The Use of DC Glow Discharges as Undergraduate Educational Tools

    SciTech Connect (OSTI)

    Stephanie A. Wissel and Andrew Zwicker, Jerry Ross, and Sophia Gershman

    2012-10-09

    Plasmas have a beguiling way of getting students excited and interested in physics. We argue that plasmas can and should be incorporated into the undergraduate curriculum as both demonstrations and advanced investigations of electromagnetism and quantum effects. Our device, based on a direct current (DC) glow discharge tube, allows for a number of experiments into topics such as electrical breakdown, spectroscopy, magnetism, and electron temperature.

  20. dc-plasma-sprayed electronic-tube device

    DOE Patents [OSTI]

    Meek, T.T.

    1982-01-29

    An electronic tube and associated circuitry which is produced by dc plasma arc spraying techniques is described. The process is carried out in a single step automated process whereby both active and passive devices are produced at very low cost. The circuitry is extremely reliable and is capable of functioning in both high radiation and high temperature environments. The size of the electronic tubes produced are more than an order of magnitude smaller than conventional electronic tubes.

  1. Synthesis of silicon nanotubes by DC arc plasma method

    SciTech Connect (OSTI)

    Tank, C. M.; Bhoraskar, S. V.; Mathe, V. L.

    2012-06-05

    Plasma synthesis is a novel technique of synthesis of nanomaterials as they provide high rate of production and promote metastable reactions. Very thin walled silicon nanotubes were synthesized in a DC direct arc thermal plasma reactor. The effect of parameters of synthesis i.e. arc current and presence of hydrogen on the morphology of Si nanoparticles is reported. Silicon nanotubes were characterized by Transmission Electron Microscopy (TEM), Local Energy Dispersive X-ray analysis (EDAX), and Scanning Tunneling Microscopy (STM).

  2. Report on Non-Contact DC Electric Field Sensors

    SciTech Connect (OSTI)

    Miles, R; Bond, T; Meyer, G

    2009-06-16

    This document reports on methods used to measure DC electrostatic fields in the range of 100 to 4000 V/m using a non-contact method. The project for which this report is written requires this capability. Non-contact measurements of DC fields is complicated by the effect of the accumulation of random space-charges near the sensors which interfere with the measurement of the field-of-interest and consequently, many forms of field measurements are either limited to AC measurements or use oscillating devices to create pseudo-AC fields. The intent of this document is to report on methods discussed in the literature for non-contact measurement of DC fields. Electric field meters report either the electric field expressed in volts per distance or the voltage measured with respect to a ground reference. Common commercial applications for measuring static (DC) electric fields include measurement of surface charge on materials near electronic equipment to prevent arcing which can destroy sensitive electronic components, measurement of the potential for lightning to strike buildings or other exposed assets, measurement of the electric fields under power lines to investigate potential health risks from exposure to EM fields and measurement of fields emanating from the brain for brain diagnostic purposes. Companies that make electric field sensors include Trek (Medina, NY), MKS Instruments, Boltek, Campbell Systems, Mission Instruments, Monroe Electronics, AlphaLab, Inc. and others. In addition to commercial vendors, there are research activities continuing in the MEMS and optical arenas to make compact devices using the principles applied to the larger commercial sensors.

  3. USCOMM-WB-DC PRELIMZNARY REPORT OH HURRICANE DAISY

    E-Print Network [OSTI]

    QC 945.2 .D3 H8 1958 c.2 #12;#12;USCOMM-WB-DC #12;PRELIMZNARY REPORT OH HURRICANE DAISY AWGUST 24-29, 1958 Hurricane "Daisy", intense but small in area, was detected as a tropical storm about 300 miles into a hurricane on August 25. A u g u s t 27 it drifted very slowly northward. coast increased. the Atlantic off

  4. Energy Incentive Programs, Washington DC | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE: AlternativeCommunication3-EDepartment ofArizona EnergyHampshire EnergyOregonTexasWashington DC

  5. Using Nyquist or Nyquist-Like Plot to Predict Three Typical Instabilities in DC-DC Converters

    E-Print Network [OSTI]

    Fang, Chung-Chieh

    2012-01-01

    By transforming an exact stability condition, a new Nyquist-like plot is proposed to predict occurrences of three typical instabilities in DC-DC converters. The three instabilities are saddle-node bifurcation (coexistence of multiple solutions), period-doubling bifurcation (subharmonic oscillation), and Neimark bifurcation (quasi-periodic oscillation). In a single plot, it accurately predicts whether an instability occurs and what type the instability is. The plot is equivalent to the Nyquist plot, and it is a useful design tool to avoid these instabilities. Nine examples are used to illustrate the accuracy of this new plot to predict instabilities in the buck or boost converter with fixed or variable switching frequency.

  6. Using Nyquist or Nyquist-Like Plot to Predict Three Typical Instabilities in DC-DC Converters

    E-Print Network [OSTI]

    Chung-Chieh Fang

    2012-04-09

    By transforming an exact stability condition, a new Nyquist-like plot is proposed to predict occurrences of three typical instabilities in DC-DC converters. The three instabilities are saddle-node bifurcation (coexistence of multiple solutions), period-doubling bifurcation (subharmonic oscillation), and Neimark bifurcation (quasi-periodic oscillation). In a single plot, it accurately predicts whether an instability occurs and what type the instability is. The plot is equivalent to the Nyquist plot, and it is a useful design tool to avoid these instabilities. Nine examples are used to illustrate the accuracy of this new plot to predict instabilities in the buck or boost converter with fixed or variable switching frequency.

  7. Multiphase soft switched DC/DC converter and active control technique for fuel cell ripple current elimination

    DOE Patents [OSTI]

    Lai, Jih-Sheng (Blacksburg, VA); Liu, Changrong (Sunnyvale, CA); Ridenour, Amy (Salem, VA)

    2009-04-14

    DC/DC converter has a transformer having primary coils connected to an input side and secondary coils connected to an output side. Each primary coil connects a full-bridge circuit comprising two switches on two legs, the primary coil being connected between the switches on each leg, each full-bridge circuit being connected in parallel wherein each leg is disposed parallel to one another, and the secondary coils connected to a rectifying circuit. An outer loop control circuit that reduces ripple in a voltage reference has a first resistor connected in series with a second resistor connected in series with a first capacitor which are connected in parallel with a second capacitor. An inner loop control circuit that reduces ripple in a current reference has a third resistor connected in series with a fourth resistor connected in series with a third capacitor which are connected in parallel with a fourth capacitor.

  8. GaN: Defect and Device Issues

    SciTech Connect (OSTI)

    Pearton, S.J.; Ren, F.; Shul, R.J.; Zolper, J.C.

    1998-11-09

    The role of extended and point defects, and key impurities such as C, O and H, on the electrical and optical properties of GaN is reviewed. Recent progress in the development of high reliability contacts, thermal processing, dry and wet etching techniques, implantation doping and isolation and gate insulator technology is detailed. Finally, the performance of GaN-based electronic and photonic devices such as field effect transistors, UV detectors, laser diodes and light-emitting diodes is covered, along with the influence of process-induced or grown-in defects and impurities on the device physics.

  9. Influence of pressure on photoluminescence and electroluminescence in GaN/InGaN/AlGaN quantum wells

    E-Print Network [OSTI]

    Weinstein, Benard.A.

    recently that the temperature shifts of the photo- and electroluminescence EL peak energies in Nichia greenV/GPa for the green and blue diodes, respectively. The observed pressure coefficients are much lower than those characteristic of the energy gap in GaN ( 40 meV/GPa) or the energy gap in InN ( 33 meV/GPa). This kind

  10. Deep Trench Capacitor based Step-up and Step-down DC/DC Converters in 32nm SOI with Opportunistic

    E-Print Network [OSTI]

    Sapatnekar, Sachin

    Deep Trench Capacitor based Step-up and Step-down DC/DC Converters in 32nm SOI with Opportunistic domains. Using ultra-high density deep trench capacitors, we are able to achieve an output power density-power domain scenario by implementing a bi-directional opportunistic current borrowing scheme. Deep trench

  11. Abstract--Emerging high-end portable electronics demand on-chip integration of high-performance dc-dc power supplies not

    E-Print Network [OSTI]

    Rincon-Mora, Gabriel A.

    series resistance (ESR) output capacitors, it is not clear how it applies to boost converters boost converter. Experimental results verified the switching supply was stable across 1-30µH, 1-350µ variation to less than 27%. Index Terms--differential control, boost dc-dc converter I. INTRODUCTION

  12. SoC Energy Savings = Reduce+Reuse+Recycle: A Case Study Using a 660MHz DC-DC Converter with Integrated Output Filter

    E-Print Network [OSTI]

    Lemieux, Guy

    that requires careful planning of the interface between the provider and receptor of the energy. In this paper between energy provider and receptor. Since fully integrated on-chip regulators are usually inefficientSoC Energy Savings = Reduce+Reuse+Recycle: A Case Study Using a 660MHz DC-DC Converter

  13. 2004 35Ih Annual IEEE Power Elearonics Specialisrs Conference Aachen, Germany,2004 Modeling of Quantization Effects in Digitally Controlled DC-DC Converters

    E-Print Network [OSTI]

    Prodiæ, Aleksandar

    : {hpeng,maksimov)@colorado.edu Abstract- In digitally controlled DC-DC converters with a single voltage variations, programmability, reduction or elimination of external passive components, as well a conservative hound for the limit-cycle oscillation amplitude, while Section VI11 summarizes the conclusions. 11

  14. 26.2 Single-Inductor Dual-Input Dual-Output Buck-Boost Fuel Cell-Li Ion Charging DC-DC Converter Supply

    E-Print Network [OSTI]

    Rincon-Mora, Gabriel A.

    1 26.2 Single-Inductor Dual-Input Dual-Output Buck-Boost Fuel Cell-Li Ion Charging DC-DC Converter battery with its energy-dense counterpart like the fuel cell (FC) improves micro-scale integration [2]. As a result, buck or boost single-inductor, dual-input, dual-output (SIDIDO) converters enjoy

  15. Abstract -This paper presents the coordinated control of distributed energy storage systems (DESSs) in DC micro-grids.

    E-Print Network [OSTI]

    Vasquez, Juan Carlos

    ) in DC micro-grids. In order to balance the state-of-charge (SoC) of each energy storage unit (ESU--Droop control; distributed energy storage system (DESS); DC micro-grids; state-of-charge (SoC) I. INTRODUCTION and more popularity [1]. Nowadays DC micro-grids are becoming more attractive with the raise of DC power

  16. 650 IEEE TRANSACTIONS ON POWER DELIVERY, VOL. 26, NO. 2, APRIL 2011 Hourly Scheduling of DC Transmission Lines in

    E-Print Network [OSTI]

    Fu, Yong

    ). The impact of VSC-DC transmission system on the economics and the security of integrated ac/dc transmission will determine the optimal hourly schedule of controllable VSC-DC transmission systems in electricity markets;LOTFJOU et al.: HOURLY SCHEDULING OF DC TRANSMISSION LINES 651 , Vector of real and reactive power

  17. 936 IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 50, NO. 5, OCTOBER 2003 Gain Adaptation of Networked DC Motor Controllers

    E-Print Network [OSTI]

    Chow, Mo-Yuen

    ) milling machine, dc motors can be connected to controllers, drivers and sensors by directly wiring

  18. InGaAs/GaAs quantum dot interdiffiusion induced by cap layer overgrowth

    SciTech Connect (OSTI)

    Jasinski, J.; Babinski, A.; Czeczott, M.; Bozek, R.

    2000-06-28

    The effect of thermal treatment during and after growth of InGaAs/GaAs quantum dot (QD) structures was studied. Transmission electron microscopy and atomic force microscopy confirmed the presence of interacting QDs, as was expected from analysis of temperature dependence of QD photoluminescence (PL) peak. The results indicate that the effect of post-growth annealing can be similar to the effect of elevated temperature of capping layer growth. Both, these thermal treatments can lead to a similar In and Ga interdiffiusion resulting in a similar blue-shift of QD PL peak.

  19. Optical spectroscopy of quantum confined states in GaAs/AlGaAs quantum well tubes

    SciTech Connect (OSTI)

    Shi, Teng; Fickenscher, Melodie; Smith, Leigh; Jackson, Howard; Yarrison-Rice, Jan; Gao, Qiang; Tan, Hoe; Jagadish, Chennupati; Etheridge, Joanne; Wong, Bryan M.

    2013-12-04

    We have investigated the quantum confinement of electronic states in GaAs/Al{sub x}Ga{sub 1?x}As nanowire heterostructures which contain radial GaAs quantum wells of either 4nm or 8nm. Photoluminescence and photoluminescence excitation spectroscopy are performed on single nanowires. We observed emission and excitation of electron and hole confined states. Numerical calculations of the quantum confined states using the detailed structural information on the quantum well tubes show excellent agreement with these optical results.

  20. Structural and optical properties of InGaN–GaN nanowire heterostructures grown by molecular beam epitaxy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Limbach, F.; Gotschke, T.; Stoica, T.; Calarco, R.; Sutter, E.; Ciston, J.; Cusco, R.; Artus, L.; Kremling, S.; Ho?fling, S.; et al

    2011-01-01

    InGaN/GaN nanowire (NW) heterostructures grown by plasma assisted molecular beam epitaxy were studied in comparison to their GaN and InGaN counterparts. The InGaN/GaN heterostructure NWs are composed of a GaN NW, a thin InGaN shell, and a multifaceted InGaN cap wrapping the top part of the GaN NW. High-resolution transmission electron microscopy (HRTEM) images taken from different parts of a InGaN/GaN NW show a wurtzite structure of the GaN core and the epitaxial InGaN shell around it, while additional crystallographic domains are observed whithin the InGaN cap region. Large changes in the lattice parameter along the wire, from pure GaNmore »to higher In concentration demonstrate the successful growth of a complex InGaN/GaN NW heterostructure. Photoluminescence (PL) spectra of these heterostructure NW ensembles show rather broad and intense emission peak at 2.1 eV. However, ?-PL spectra measured on single NWs reveal a reduced broadening of the visible luminescence. The analysis of the longitudinal optical phonon Raman peak position and its shape reveal a variation in the In content between 20% and 30%, in agreement with the values estimated by PL and HRTEM investigations. The reported studies are important for understanding of the growth and properties of NW heterostructures suitable for applications in optoelectronics and photovoltaics.« less

  1. Evaluation of electropolished stainless steel electrodes for use in DC high voltage photoelectron guns

    SciTech Connect (OSTI)

    BastaniNejad, Mahzad; Elmustafa, Abdelmageed A.; Forman, Eric; Covert, Steven; Hansknecht, John; Hernandez-Garcia, Carlos; Poelker, Matthew; Das, Lopa; Kelley, Michael; Williams, Phillip

    2015-07-01

    DC high voltage photoelectron guns are used to produce polarized electron beams for accelerator-based nuclear and high-energy physics research. Low-level field emission (~nA) from the cathode electrode degrades the vacuum within the photogun and reduces the photoelectron yield of the delicate GaAs-based photocathode used to produce the electron beams. High-level field emission (>?A) can cause significant damage the photogun. To minimize field emission, stainless steel electrodes are typically diamond-paste polished, a labor-intensive process often yielding field emission performance with a high degree of variability, sample to sample. As an alternative approach and as comparative study, the performance of electrodes electropolished by conventional commercially available methods is presented. Our observations indicate the electropolished electrodes exhibited less field emission upon the initial application of high voltage, but showed less improvement with gas conditioning compared to the diamond-paste polished electrodes. In contrast, the diamond-paste polished electrodes responded favorably to gas conditioning, and ultimately reached higher voltages and field strengths without field emission, compared to electrodes that were only electropolished. The best performing electrode was one that was both diamond-paste polished and electropolished, reaching a field strength of 18.7 MV/m while generating less than 100 pA of field emission. The speculate that the combined processes were the most effective at reducing both large and small scale topography. However, surface science evaluation indicates topography cannot be the only relevant parameter when it comes to predicting field emission performance.

  2. Evaluation of electropolished stainless steel electrodes for use in DC high voltage photoelectron guns

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    BastaniNejad, Mahzad; Elmustafa, Abdelmageed A.; Forman, Eric; Covert, Steven; Hansknecht, John; Hernandez-Garcia, Carlos; Poelker, Matthew; Das, Lopa; Kelley, Michael; Williams, Phillip

    2015-07-01

    DC high voltage photoelectron guns are used to produce polarized electron beams for accelerator-based nuclear and high-energy physics research. Low-level field emission (~nA) from the cathode electrode degrades the vacuum within the photogun and reduces the photoelectron yield of the delicate GaAs-based photocathode used to produce the electron beams. High-level field emission (>?A) can cause significant damage the photogun. To minimize field emission, stainless steel electrodes are typically diamond-paste polished, a labor-intensive process often yielding field emission performance with a high degree of variability, sample to sample. As an alternative approach and as comparative study, the performance of electrodes electropolishedmore »by conventional commercially available methods is presented. Our observations indicate the electropolished electrodes exhibited less field emission upon the initial application of high voltage, but showed less improvement with gas conditioning compared to the diamond-paste polished electrodes. In contrast, the diamond-paste polished electrodes responded favorably to gas conditioning, and ultimately reached higher voltages and field strengths without field emission, compared to electrodes that were only electropolished. The best performing electrode was one that was both diamond-paste polished and electropolished, reaching a field strength of 18.7 MV/m while generating less than 100 pA of field emission. The speculate that the combined processes were the most effective at reducing both large and small scale topography. However, surface science evaluation indicates topography cannot be the only relevant parameter when it comes to predicting field emission performance.« less

  3. Evaluation of electropolished stainless steel electrodes for use in DC high voltage photoelectron guns

    SciTech Connect (OSTI)

    BastaniNejad, Mahzad Elmustafa, Abdelmageed A.; Forman, Eric; Covert, Steven; Hansknecht, John; Hernandez-Garcia, Carlos; Poelker, Matthew; Das, Lopa; Kelley, Michael; Williams, Phillip

    2015-07-15

    DC high voltage photoelectron guns are used to produce polarized electron beams for accelerator-based nuclear and high-energy physics research. Low-level field emission (?nA) from the cathode electrode degrades the vacuum within the photogun and reduces the photoelectron yield of the delicate GaAs-based photocathode used to produce the electron beams. High-level field emission (>?A) can cause significant damage the photogun. To minimize field emission, stainless steel electrodes are typically diamond-paste polished, a labor-intensive process often yielding field emission performance with a high degree of variability, sample to sample. As an alternative approach and as comparative study, the performance of electrodes electropolished by conventional commercially available methods is presented. Our observations indicate the electropolished electrodes exhibited less field emission upon the initial application of high voltage, but showed less improvement with gas conditioning compared to the diamond-paste polished electrodes. In contrast, the diamond-paste polished electrodes responded favorably to gas conditioning, and ultimately reached higher voltages and field strengths without field emission, compared to electrodes that were only electropolished. The best performing electrode was one that was both diamond-paste polished and electropolished, reaching a field strength of 18.7 MV/m while generating less than 100?pA of field emission. The authors speculate that the combined processes were the most effective at reducing both large and small scale topography. However, surface science evaluation indicates topography cannot be the only relevant parameter when it comes to predicting field emission performance.

  4. IEEE Energy2030 Atlanta, GA USA

    E-Print Network [OSTI]

    Gross, George

    of an aggregation of battery vehicles for the provision of frequency regulation ­ requiring very fast response timesIEEE Energy2030 Atlanta, GA USA 17-18 November, 2008 Design of a Conceptual Framework for the V2G in common is the batteries, which provide good storage capacity that can be effectively integrated

  5. 495 Tech Way NW Atlanta, GA 30318

    E-Print Network [OSTI]

    Li, Mo

    495 Tech Way NW Atlanta, GA 30318 404.385.0384 comments@energy.gatech.edu Copyright 2014 · Georgia concerns, low-cost, clean, secure energy solutions will be necessary to address our global energy needs and sustain our way of life. Georgia Tech Energy Innovations The Strategic Energy Institute's scientists

  6. Defect studies in low-temperature-grown GaAs

    SciTech Connect (OSTI)

    Bliss, D.E.

    1992-11-01

    High content of excess As is incorporated in GaAs grown by low-temperature molecular-beam-epitaxy (LTMBE). The excess As exists primarily as As antisite defects AsGa and a lesser extent of gallium vacancies V[sub Ga]. The neutral AsGa-related defects were measured by infrared absorption at 1[mu]m. Gallium vacancies, V[sub Ga], was investigated by slow positron annihilation. Dependence of defect contents on doping was studied by Si and Be dopants. No free carriers are generated by n-type or p-type doping up to 10[sup 19] cm[sup [minus]3] Si or Be. Raman data indicate Be occupies Ga substitutional sites but Si atom is not substitutional. Si induces more As[sub Ga] in the layer. As As[sub Ga] increases, photoquenchable As[sub Ga] decreases. Fraction of photoquenchable defects correlates to defects within 3 nearest neighbor separations disrupting the metastability. Annealing reduces neutral As[sub Ga] content around 500C, similar to irradiation damaged and plastically deformed Ga[sub As], as opposed to bulk grown GaAs in which As[sub Ga]-related defects are stable up to 1100C. The lower temperature defect removal is due to V[sub Ga] enhanced diffusion of As[sub Ga] to As precipitates. The supersaturated V[sub GA] and also decreases during annealing. Annealing kinetics for As[sub Ga]-related defects gives 2.0 [plus minus] 0.3 eV and 1.5 [plus minus] 0.3 eV migration enthalpies for the As[sub Ga] and V[sub Ga]. This represents the difference between Ga and As atoms hopping into the vacancy. The non-photoquenchable As[sub Ga]-related defects anneal with an activation energy of 1.1 [plus minus] 0.3eV. Be acceptors can be activated by 800C annealing. Temperature difference between defect annealing and Be activation formation of As[sub Ga]-Be[sub Ga] pairs. Si donors can only be partially activated.

  7. Electron mobility enhancement in AlN/GaN/AlN heterostructures with InGaN nanogrooves

    E-Print Network [OSTI]

    it was discovered by Davydov et al.1 and con- firmed by independent studies2,3 that its band gap is small, EG InN =0 The conduction band offset at GaN/AlN interface was estimated as EQW=0.7 EG AlN -EG GaN =1918 meV. The nanoN/GaN/AlN QW. The depth of the nanogroove is calculated as E0=0.8 EG GaN -EG InxGa1-xN . The band gap of InxGa1

  8. Development and Industrialization of InGaN/GaN LEDs on Patterned...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    epitaxial growth of indium gallium nitride (InGaN) layers capable of producing high-efficiency LEDs when combined with chip-on-board packaging techniques. The proposed...

  9. High-field quasi-ballistic transport in AlGaN/GaN heterostructures

    SciTech Connect (OSTI)

    Danilchenko, B. A.; Tripachko, N. A.; Belyaev, A. E.; Vitusevich, S. A. Hardtdegen, H.; Lüth, H.

    2014-02-17

    Mechanisms of electron transport formation in 2D conducting channels of AlGaN/GaN heterostructures in extremely high electric fields at 4.2?K have been studied. Devices with a narrow constriction for the current flow demonstrate high-speed electron transport with an electron velocity of 6.8?×?10{sup 7}?cm/s. Such a velocity is more than two times higher than values reported for conventional semiconductors and about 15% smaller than the limit value predicted for GaN. Superior velocity is attained in the channel with considerable carrier reduction. The effect is related to a carrier runaway phenomenon. The results are in good agreement with theoretical predictions for GaN-based materials.

  10. 2DEG electrodes for piezoelectric transduction of AlGaN/GaN MEMS resonators

    E-Print Network [OSTI]

    Weinstein, Dana

    A 2D electron gas (2DEG) interdigitated transducer (IDT) in Gallium Nitride (GaN) resonators is introduced and demonstrated. This metal-free transduction does not suffer from the loss mechanisms associated with more commonly ...

  11. Emission and Excitation Spectra of ZnO:Ga and ZnO:Ga,N Ceramics

    E-Print Network [OSTI]

    P. A. Rodnyi; I. V. Khodyuk; E. I. Gorokhova; S. B. Mikhrin; P. Dorenbos

    2010-09-07

    The spectral characteristics of ZnO:Ga and ZnO:Ga,N ceramics prepared by uniaxial hot pressing have been investigated. At room temperature, the edge (exciton) band at 3.12 eV dominates in the luminescence spectra of ZnO:Ga, while a wide luminescence band at 2.37 eV, which is likely to be due to zinc vacancies, is observed in the spectra of ZnO:Ga,N. Upon heating, the edge band maximum shifts to lower energies and the bandwidth increases. The extrapolated position of the edge-band maximum at zero temperature, Em(0) = 3.367 +/- 0.005 eV, is in agreement with the data for thin zinc oxide films. The luminescence excitation spectra in the range from 3 to 6.5 eV are reported and the mechanism of energy transfer to excitons and luminescence centers is considered.

  12. Composition profiling of GaAs/AlGaAs quantum dots grown by droplet epitaxy

    SciTech Connect (OSTI)

    Bocquel, J.; Koenraad, P. M. [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Giddings, A. D.; Prosa, T. J.; Larson, D. J. [CAMECA Instruments, Inc., 5500 Nobel Drive, Madison, Wisconsin 53711 (United States); Mano, T. [National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan)

    2014-10-13

    Droplet epitaxy (DE) is a growth method which can create III-V quantum dots (QDs) whose optoelectronic properties can be accurately controlled through the crystallisation conditions. In this work, GaAs/AlGaAs DE-QDs have been analyzed with the complimentary techniques of cross-sectional scanning tunneling microscopy and atom probe tomography. Structural details and a quantitative chemical analysis of QDs of different sizes are obtained. Most QDs were found to be pure GaAs, while a small proportion exhibited high intermixing caused by a local etching process. Large QDs with a high aspect ratio were observed to have an Al-rich crown above the GaAs QD. This structure is attributed to differences in mobility of the cations during the capping phase of the DE growth.

  13. On strongly GA-convex functions and stochastic processes

    SciTech Connect (OSTI)

    Bekar, Nurgül Okur; Akdemir, Hande Günay; ??can, ?mdat

    2014-08-20

    In this study, we introduce strongly GA-convex functions and stochastic processes. We provide related well-known Kuhn type results and Hermite-Hadamard type inequality for strongly GA-convex functions and stochastic processes.

  14. Energy absorption in Ni-Mn-Ga/ polymer composites

    E-Print Network [OSTI]

    Feuchtwanger, Jorge

    2006-01-01

    In recent years Ni-Mn-Ga has attracted considerable attention as a new kind of actuator material. Off-stoichiometric single crystals of Ni2MnGa can regularly exhibit 6% strain in tetragonal martensites and orthorhombic ...

  15. Materials with low DC magnetic susceptibility for sensitive magnetic measurements

    E-Print Network [OSTI]

    Rakshya Khatiwada; Lawrence Dennis; Rachel Kendrick; Marjan Khosravi; Michael Peters; Erick Smith; Mike Snow

    2015-06-30

    Materials with very low DC magnetic susceptibility have many scientific applications. To our knowledge however, relatively little research has been conducted with the goal to produce a totally nonmagnetic material. This phrase in our case means after spatially averaging over macroscopic volumes, it possesses an average zero DC magnetic susceptibility. We report measurements of the DC magnetic susceptibility of three different types of nonmagnetic materials at room temperature: (I) solutions of paramagnetic salts and diamagnetic liquids, (II) liquid gallium-indium alloys and (III) pressed powder mixtures of tungsten and bismuth. The lowest measured magnetic susceptibility among these candidate materials is in the order of 10^-9 cgs volume susceptibility units, about two orders of magnitude smaller than distilled water. In all cases, the measured concentration dependence of the magnetic susceptibility is consistent with that expected for the weighted sum of the susceptibilities of the separate components within experimental error. These results verify the Wiedemann additivity law and thereby realize the ability to produce materials with small but tunable magnetic susceptibility. For our particular scientific application, we are also looking for materials with the largest possible number of neutrons and protons per unit volume. The gallium-indium alloys fabricated and measured in this work possess to our knowledge the smallest ratio of volume magnetic susceptibility to nucleon number density per unit volume for a room temperature liquid, and the tungsten-bismuth pressed powder mixtures possess to our knowledge the smallest ratio of volume magnetic susceptibility to nucleon number density per unit volume for a room temperature solid. This ratio is a figure of merit for a certain class of precision experiments that search for possible exotic spin-dependent forces of Nature.

  16. InGaAs/GaAs (110) quantum dot formation via step meandering

    SciTech Connect (OSTI)

    Diez-Merino, Laura; Tejedor, Paloma

    2011-07-01

    InGaAs (110) semiconductor quantum dots (QDs) offer very promising prospects as a material base for a new generation of high-speed spintronic devices, such as single electron transistors for quantum computing. However, the spontaneous formation of InGaAs QDs is prevented by two-dimensional (2D) layer-by-layer growth on singular GaAs (110) substrates. In this work we have studied, by using atomic force microscopy and photoluminescence spectroscopy (PL), the growth of InGaAs/GaAs QDs on GaAs (110) stepped substrates by molecular beam epitaxy (MBE), and the modification of the adatom incorporation kinetics to surface steps in the presence of chemisorbed atomic hydrogen. The as-grown QDs exhibit lateral dimensions below 100 nm and emission peaks in the 1.35-1.37 eV range. It has been found that a step meandering instability derived from the preferential attachment of In adatoms to [110]-step edges relative to [11n]-type steps plays a key role in the destabilization of 2D growth that leads to 3D mound formation on both conventional and H-terminated vicinal substrates. In the latter case, the driving force for 3D growth via step meandering is enhanced by H-induced upward mass transport in addition to the lower energy cost associated with island formation on H-terminated substrates, which results in a high density array of InGaAs/GaAs dots selectively nucleated on the terrace apices with reduced lateral dimensions and improved PL efficiency relative to those of conventional MBE-grown samples.

  17. Sheet resistance under Ohmic contacts to AlGaN/GaN heterostructures

    SciTech Connect (OSTI)

    Haj?asz, M., E-mail: m.hajlasz@m2i.nl [Materials innovation institute (M2i), Mekelweg 2, 2628 CD, Delft (Netherlands); MESA Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE, Enschede (Netherlands); Donkers, J. J. T. M.; Sque, S. J.; Heil, S. B. S. [NXP Semiconductors Research, High Tech Campus 46, 5656 AE, Eindhoven (Netherlands); Gravesteijn, D. J. [NXP Semiconductors Research, High Tech Campus 46, 5656 AE, Eindhoven (Netherlands); MESA Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE, Enschede (Netherlands); Rietveld, F. J. R. [NXP Semiconductors, Gerstweg 2, 6534 AE, Nijmegen (Netherlands); Schmitz, J. [MESA Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE, Enschede (Netherlands)

    2014-06-16

    For the determination of specific contact resistance in semiconductor devices, it is usually assumed that the sheet resistance under the contact is identical to that between the contacts. This generally does not hold for contacts to AlGaN/GaN structures, where an effective doping under the contact is thought to come from reactions between the contact metals and the AlGaN/GaN. As a consequence, conventional extraction of the specific contact resistance and transfer length leads to erroneous results. In this Letter, the sheet resistance under gold-free Ti/Al-based Ohmic contacts to AlGaN/GaN heterostructures on Si substrates has been investigated by means of electrical measurements, transmission electron microscopy, and technology computer-aided design simulations. It was found to be significantly lower than that outside of the contact area; temperature-dependent electrical characterization showed that it exhibits semiconductor-like behavior. The increase in conduction is attributed to n-type activity of nitrogen vacancies in the AlGaN. They are thought to form during rapid thermal annealing of the metal stack when Ti extracts nitrogen from the underlying semiconductor. The high n-type doping in the region between the metal and the 2-dimensional electron gas pulls the conduction band towards the Fermi level and enhances horizontal electron transport in the AlGaN. Using this improved understanding of the properties of the material underneath the contact, accurate values of transfer length and specific contact resistance have been extracted.

  18. AlGaAs/GaAs photovoltaic converters for high power narrowband radiation

    SciTech Connect (OSTI)

    Khvostikov, Vladimir; Kalyuzhnyy, Nikolay; Mintairov, Sergey; Potapovich, Nataliia; Shvarts, Maxim; Sorokina, Svetlana; Andreev, Viacheslav; Luque, Antonio

    2014-09-26

    AlGaAs/GaAs-based laser power PV converters intended for operation with high-power (up to 100 W/cm{sup 2}) radiation were fabricated by LPE and MOCVD techniques. Monochromatic (? = 809 nm) conversion efficiency up to 60% was measured at cells with back surface field and low (x = 0.2) Al concentration 'window'. Modules with a voltage of 4 V and the efficiency of 56% were designed and fabricated.

  19. Guided Neuronal Growth on Arrays of Biofunctionalized GaAs/InGaAs Semiconductor Microtubes

    E-Print Network [OSTI]

    Cornelius S. Bausch; Aune Koitmäe; Eric Stava; Amanda Price; Pedro J. Resto; Yu Huang; David Sonnenberg; Yuliya Stark; Christian Heyn; Justin C. Williams; Erik W. Dent; Robert H. Blick

    2013-05-06

    We demonstrate embedded growth of cortical mouse neurons in dense arrays of semiconductor microtubes. The microtubes, fabricated from a strained GaAs/InGaAs heterostructure, guide axon growth through them and enable electrical and optical probing of propagating action potentials. The coaxial nature of the microtubes -- similar to myelin -- is expected to enhance the signal transduction along the axon. We present a technique of suppressing arsenic toxicity and prove the success of this technique by overgrowing neuronal mouse cells.

  20. Positron lifetime spectrometer using a DC positron beam

    DOE Patents [OSTI]

    Xu, Jun; Moxom, Jeremy

    2003-10-21

    An entrance grid is positioned in the incident beam path of a DC beam positron lifetime spectrometer. The electrical potential difference between the sample and the entrance grid provides simultaneous acceleration of both the primary positrons and the secondary electrons. The result is a reduction in the time spread induced by the energy distribution of the secondary electrons. In addition, the sample, sample holder, entrance grid, and entrance face of the multichannel plate electron detector assembly are made parallel to each other, and are arranged at a tilt angle to the axis of the positron beam to effectively separate the path of the secondary electrons from the path of the incident positrons.

  1. Hardwired Control Changes For NSTX DC Power Feeds

    SciTech Connect (OSTI)

    Ramakrishnan, S.

    2013-06-28

    The National Spherical Torus Experiment (NSTX) has been designed and installed in the existing facilities at Princeton Plasma Physics Laboratory (PPPL). Most of the hardware, plant facilities, auxiliary sub-systems, and power systems originally used for the Tokamak Fusion Test Reactor (TFTR) have been used with suitable modifications to reflect NSTX needs. The original TFTR Hardwired Control System (HCS) with electromechanical relays was used for NSTX DC Power loop control and protection during NSTX operations. As part of the NSTX Upgrade, the HCS is being changed to a PLC-based system with the same control logic. This paper gives a description of the changeover to the new PLC-based system __________________________________________________

  2. Heteroepitaxial Ge-on-Si by DC magnetron sputtering

    SciTech Connect (OSTI)

    Steglich, Martin; Schrempel, Frank; Füchsel, Kevin; Kley, Ernst-Bernhard; Patzig, Christian; Berthold, Lutz; Höche, Thomas; Tünnermann, Andreas; Fraunhofer Institute for Applied Optics and Precision Engineering IOF, Albert-Einstein-Str. 7, 07745 Jena

    2013-07-15

    The growth of Ge on Si(100) by DC Magnetron Sputtering at various temperatures is studied by Spectroscopic Ellipsometry and Transmission Electron Microscopy. Smooth heteroepitaxial Ge films are prepared at relatively low temperatures of 380°C. Typical Stransky-Krastanov growth is observed at 410°C. At lower temperatures (320°C), films are essentially amorphous with isolated nanocrystallites at the Si-Ge interface. A minor oxygen contamination at the interface, developing after ex-situ oxide removal, is not seen to hinder epitaxy. Compensation of dislocation-induced acceptors in Ge by sputtering from n-doped targets is proposed.

  3. EA-327-A DC Energy, LLC | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustmentsShirleyEnergy A plug-inPPL EnergyPlus, LLC to export electricSilverhill Ltdto export electricDC

  4. EA-351 DC Energy Dakota, LLC | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustmentsShirleyEnergy A plug-inPPL EnergyPlus, LLC to export electricSilverhillSaracenCreditNextEraDC

  5. EA-377 DC Energy Texas | Department of Energy

    Broader source: Energy.gov (indexed) [DOE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustmentsShirleyEnergy A plug-inPPL EnergyPlus, LLC to exportEndure Energy,Vitol Inc toDC Energy Texas to

  6. Category:DC Resistivity Survey (Wenner Array) | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION JEnvironmentalBowerbank,Cammack Village,8199089°,AnalyticalCuttings Analysis JumpDC Resistivity

  7. Global DC Power System Market Analysis | OpenEI Community

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIXsource History View New Pages RecentPlant <SilverChange Associates JumpGlobal DC Power

  8. DC Resistivity Survey (Dipole-Dipole Array) | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIX ECoopButtePower VenturesInformation9) Wind Farm JumpAlum|Cyclone PowerD1DC

  9. Categorical Exclusion Determinations: Washington, D.C. | Department of

    Broader source: Energy.gov (indexed) [DOE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of Natural GasAdjustmentsShirleyEnergyTher i n c i p a lCaribElectricSouth Dakota. DOCUMENTSEnergy Washington, D.C.

  10. Lateral and Vertical Transistors Using the AlGaN/GaN Heterostructure

    SciTech Connect (OSTI)

    Chowdhury, S; Mishra, UK

    2013-10-01

    Power conversion losses are endemic in all areas of electricity consumption, including motion control, lighting, air conditioning, and information technology. Si, the workhorse of the industry, has reached its material limits. Increasingly, the lateral AlGaN/GaN HEMT based on gallium nitride (GaN-on-Si) is becoming the device of choice for medium power electronics as it enables high-power conversion efficiency and reduced form factor at attractive pricing for wide market penetration. The reduced form factor enabled by high-efficiency operation at high frequency further enables significant system price reduction because of savings in bulky extensive passive elements and heat sink costs. The high-power market, however, still remains unaddressed by lateral GaN devices. The current and voltage demand for high power conversion application makes the chip area in a lateral topology so large that it becomes more difficult to manufacture. Vertical GaN devices would play a big role alongside of silicon carbide (SiC) to address the high power conversion needs. In this paper, the development, performance, and status of lateral and vertical GaN devices are discussed.

  11. GaNPAs Solar Cells Lattice-Matched To GaP: Preprint

    SciTech Connect (OSTI)

    Geisz, J. F.; Friedman, D. J.; Kurtz, S.

    2002-05-01

    This conference paper describes the III-V semiconductors grown on silicon substrates are very attractive for lower-cost, high-efficiency multijunction solar cells, but lattice-mismatched alloys that result in high dislocation densities have been unable to achieve satisfactory performance. GaNxP1-x-yAsy is a direct-gap III-V alloy that can be grown lattice-matched to Si when y= 4.7x - 0.1. We propose the use of lattice-matched GaNPAs on silicon for high-efficiency multijunction solar cells. We have grown GaNxP1-x-yAsy on GaP (with a similar lattice constant to silicon) by metal-organic chemical vapor phase epitaxy with direct band-gaps in the range of 1.5 to 2.0 eV. We demonstrate the performance of single-junction GaNxP1-x-yAsy solar cells grown on GaP substrates and discuss the prospects for the development of monolithic high-efficiency multijunction solar cells based on silicon substrates.

  12. Accurate characterization and improvement of GaAs microstrip attenuation 

    E-Print Network [OSTI]

    Carroll, James Mason

    1992-01-01

    Convergence. III. E. 6 Final Model. III. F Simulation Results for 100 um GaAs. . III. F. 1 On-GaAs Microstrip. III. I', 2 Suspended Microstrip Line . . . . 50 . . . . 51 . . . . 54 . . . . 56 . . . . 56 . . . 56 . . . . 64 64 . . . , 64 III. F. 3... Comparison Between On-GaAs and Suspcndcd Microstrip . . . 68 III. F. 4 Microstrip Inductance III. G EM Parameters in CAD Simulations . . III. H Simulation Results for 150 um GaAs. III. I Conclusions and Recommendations. IV RESEARCH ACCOMPLISHMENTS...

  13. Advanced technologies for improving high frequency performance of AlGaN/GaN high electron mobility transistors

    E-Print Network [OSTI]

    Chung, Jinwook W. (Jinwook Will)

    2008-01-01

    In this thesis, we have used a combination of physical analysis, numerical simulation and experimental work to identify and overcome some of the main challenges in AlGaN/GaN high electron mobility transistors (HEMTs) for ...

  14. A New Combustion Synthesis Method for GaN:Eu3+ and Ga2O3 :Eu3+

    E-Print Network [OSTI]

    McKittrick, Joanna

    A New Combustion Synthesis Method for GaN:Eu3+ and Ga2O3 :Eu3+ Luminescent Powders G. A. Hirata1 between the precursors. The preparation of Eu-doped Ga2O3 powders was achieved using a new combustion)3 and Ga(NO3)3 as the precursors and hydrazine as (non-carbonaceous) fuel. A spontaneous combustion

  15. Single-mode deformation via nanoindentation in dc-Si

    SciTech Connect (OSTI)

    Wong, Sherman; Haberl, Bianca; Williams, James S.; Bradby, Jodie E.

    2015-01-01

    The mixture of the metastable body-centered cubic (bc8) and rhombohedral (r8) phases of silicon that is formed via nanoindentation of diamond cubic (dc) silicon exhibits properties that are of scientifc and technological interest. This letter demonstrates that large regions of this mixed phase can be formed in crystalline Si via nanoindentation without signifcant damage to the surrounding crystal. Cross-sectional transmission electron microscopy is used to show that volumes 6 um wide and up to 650 nm deep can be generated in this way using a spherical tip of 21.5 um diameter. The phase transformed region is characterised using both Raman microspectroscopy and transmission electron microscopy. It is found that uniform loading using large spherical indenters can favor phase transformation as the sole deformation mechanism as long as the maximum load is below a critical level. We suggest that the sluggish nature of the transformation from the dc-Si phase to the metallic (b-Sn) phase normally results in competing deformation mechanisms such as slip and cracking but these can be suppressed by controlled loading conditions.

  16. DC switching regulated power supply for driving an inductive load

    DOE Patents [OSTI]

    Dyer, G.R.

    1983-11-29

    A dc switching regulated power supply for driving an inductive load is provided. The regulator basic circuit is a bridge arrangement of diodes and transistors. First and second opposite legs of the bridge are formed by first and second parallel-connected transistor arrays, respectively, while the third and fourth legs of the bridge are formed by appropriately connected first and second parallel connected diode arrays, respectively. A dc power supply is connected to the input of the bridge and the output is connected to the load. A servo controller is provided to control the switching rate of the transistors to maintain a desired current to the load. The regulator may be operated in three stages or modes: (1) for current runup in the load, both first and second transistor switch arrays are turned on and current is supplied to the load through both transistor arrays. (2) When load current reaches the desired level, the first switch is turned off, and load current flywheels through the second switch array and the fourth leg diode array connecting the second switch array in series with the load. Current is maintained by alternating between modes 1 and 2 at a suitable duty cycle and switching rate set by the controller. (3) Rapid current rundown is accomplished by turning both switch arrays off, allowing load current to be dumped back into the source through the third and fourth diode arrays connecting the source in series opposition with the load to recover energy from the inductive load.

  17. Optimizing Energy Savings from Direct-DC in U.S. Residential Buildings

    E-Print Network [OSTI]

    Garbesi, Karina

    2012-01-01

    ballast fluorescent and LED lighting, which are DC- internalmotors [7]. Fluorescent and LED lighting uses one-quarter ofbest technology Lighting Incandescent, fluorescent, LED

  18. Harnessing the Power of the Sun, Solar Impulse Plane Lands in DC Area

    Office of Energy Efficiency and Renewable Energy (EERE)

    Today, Secretary Moniz spoke at an event welcoming the arrival of the solar-powered Solar Impulse plane at Dulles International Airport near Washington, D.C.

  19. Optimizing Energy Savings from Direct-DC in U.S. Residential Buildings

    E-Print Network [OSTI]

    Garbesi, Karina

    2012-01-01

    motors [7]. Fluorescent and LED lighting uses one-quarter ofballast fluorescent and LED lighting, which are DC- internalbest technology Lighting Incandescent, fluorescent, LED

  20. DC Resistivity Survey (Dipole-Dipole Array) At Mt Princeton Hot...

    Open Energy Info (EERE)

    1971) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: DC Resistivity Survey (Dipole-Dipole Array) At Mt Princeton Hot Springs Geothermal Area...

  1. Optimization of spin-torque switching using AC and DC pulses

    SciTech Connect (OSTI)

    Dunn, Tom [Department of Physics, University of Minnesota, Minneapolis, Minnesota 55455 (United States); Kamenev, Alex [Department of Physics, University of Minnesota, Minneapolis, Minnesota 55455 (United States); Fine Theoretical Physics Institute, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

    2014-06-21

    We explore spin-torque induced magnetic reversal in magnetic tunnel junctions using combined AC and DC spin-current pulses. We calculate the optimal pulse times and current strengths for both AC and DC pulses as well as the optimal AC signal frequency, needed to minimize the Joule heat lost during the switching process. The results of this optimization are compared against numeric simulations. Finally, we show how this optimization leads to different dynamic regimes, where switching is optimized by either a purely AC or DC spin-current, or a combination AC/DC spin-current, depending on the anisotropy energies and the spin-current polarization.

  2. Improved device performance of InAs/GaAs quantum dot solar cells with GaP strain compensation layers

    E-Print Network [OSTI]

    Jalali. Bahram

    Improved device performance of InAs/GaAs quantum dot solar cells with GaP strain compensation Center for High Technology Materials, University of New Mexico, 1313 Goddard SE, Albuquerque, New Mexico optical, electrical, and spectral response characteristics of three-stack InAs/GaAs quantum dot solar

  3. Lattice-Mismatched GaAs/InGaAs Two-Junction Solar Cells by Direct Wafer Bonding

    SciTech Connect (OSTI)

    Tanabe, K.; Aiken, D. J.; Wanlass, M. W.; Morral, A. F.; Atwater, H. A.

    2006-01-01

    Direct bonded interconnect between subcells of a lattice-mismatched III-V compound multijunction cell would enable dislocation-free active regions by confining the defect network needed for lattice mismatch accommodation to tunnel junction interfaces, while metamorphic growth inevitably results in less design flexibility and lower material quality than is desirable. The first direct-bond interconnected multijunction solar cell, a two-terminal monolithic GaAs/InGaAs two-junction solar cell, is reported and demonstrates viability of direct wafer bonding for solar cell applications. The tandem cell open-circuit voltage was approximately the sum of the subcell open-circuit voltages. This achievement shows direct bonding enables us to construct lattice-mismatched III-V multijunction solar cells and is extensible to an ultrahigh efficiency InGaP/GaAs/InGaAsP/InGaAs four-junction cell by bonding a GaAs-based lattice-matched InGaP/GaAs subcell and an InP-based lattice-matched InGaAsP/InGaAs subcell. The interfacial resistance experimentally obtained for bonded GaAs/InP smaller than 0.10 Ohm-cm{sup 2} would result in a negligible decrease in overall cell efficiency of {approx}0.02%, under 1-sun illumination.

  4. Properties of (Ga,Mn)As codoped with Li

    SciTech Connect (OSTI)

    Miyakozawa, Shohei; Chen, Lin; Matsukura, Fumihiro; Ohno, Hideo

    2014-06-02

    We grow Li codoped (Ga,Mn)As layers with nominal Mn composition up to 0.15 by molecular beam epitaxy. The layers before and after annealing are characterized by x-ray diffraction, transport, magnetization, and ferromagnetic resonance measurements. The codoping with Li reduces the lattice constant and electrical resistivity of (Ga,Mn)As after annealing. We find that (Ga,Mn)As:Li takes similar Curie temperature to that of (Ga,Mn)As, but with pronounced magnetic moments and in-plane magnetic anisotropy, indicating that the Li codoping has nontrivial effects on the magnetic properties of (Ga,Mn)As.

  5. 56 IEEE JOURNAL OF PHOTOVOLTAICS, VOL. 2, NO. 1, JANUARY 2012 Metamorphic GaAsP and InGaP Solar Cells on GaAs

    E-Print Network [OSTI]

    Haller, Gary L.

    solar cells are triple-junction concentrator devices, with each junction efficiently col- lecting subcell in a multijunction de- vice. GaAs0.66 P0.34 single-junction solar cells with Eg = 1.83 eV were56 IEEE JOURNAL OF PHOTOVOLTAICS, VOL. 2, NO. 1, JANUARY 2012 Metamorphic GaAsP and InGaP Solar

  6. Reactive codoping of GaAlInP compound semiconductors

    DOE Patents [OSTI]

    Hanna, Mark Cooper (Boulder, CO); Reedy, Robert (Golden, CO)

    2008-02-12

    A GaAlInP compound semiconductor and a method of producing a GaAlInP compound semiconductor are provided. The apparatus and method comprises a GaAs crystal substrate in a metal organic vapor deposition reactor. Al, Ga, In vapors are prepared by thermally decomposing organometallic compounds. P vapors are prepared by thermally decomposing phospine gas, group II vapors are prepared by thermally decomposing an organometallic group IIA or IIB compound. Group VIB vapors are prepared by thermally decomposing a gaseous compound of group VIB. The Al, Ga, In, P, group II, and group VIB vapors grow a GaAlInP crystal doped with group IIA or IIB and group VIB elements on the substrate wherein the group IIA or IIB and a group VIB vapors produced a codoped GaAlInP compound semiconductor with a group IIA or IIB element serving as a p-type dopant having low group II atomic diffusion.

  7. Three-junction solar cells comprised of a thin-film GaInP/GaAs tandem cell mechanically stacked on a Si cell

    SciTech Connect (OSTI)

    Yazawa, Y.; Tamura, K.; Watahiki, S.; Kitatani, T.; Ohtsuka, H.; Warabisako, T.

    1997-12-31

    Three-junction tandem solar cells were fabricated by mechanical stacking of a thin-film GaInP/GaAs monolithic tandem cell and a Si cell. The epitaxial lift-off (ELO) technique was used for the thinning of GaInP/GaAs tandem cells. Both spectral responses of the GaInP top cell and the GaAs middle cell in the thin-film GaInP/GaAs monolithic tandem cell were conserved. The Si cell performance has been improved by reducing the absorption loss in the GaAs substrate.

  8. Chemical beam epitaxy growth of AlGaAs/GaAs tunnel junctions using trimethyl aluminium for multijunction solar cells

    SciTech Connect (OSTI)

    Paquette, B.; DeVita, M.; Turala, A.; Kolhatkar, G.; Boucherif, A.; Jaouad, A.; Aimez, V.; Arès, R.; Wilkins, M.; Wheeldon, J. F.; Walker, A. W.; Hinzer, K.; Fafard, S.

    2013-09-27

    AlGaAs/GaAs tunnel junctions for use in high concentration multijunction solar cells were designed and grown by chemical beam epitaxy (CBE) using trimethyl aluminium (TMA) as the p-dopant source for the AlGaAs active layer. Controlled hole concentration up to 4?10{sup 20} cm{sup ?3} was achieved through variation in growth parameters. Fabricated tunnel junctions have a peak tunneling current up to 6140 A/cm{sup 2}. These are suitable for high concentration use and outperform GaAs/GaAs tunnel junctions.

  9. SECONDARY MINERALS FOUND IN CORES DC2 Al AND DC2 TAKEN FROM THE GRANDE RONDE BASALT FORMATION, PASCO BASIN, WASHINGTON

    E-Print Network [OSTI]

    Teague, L.S.

    2010-01-01

    of secondary and primary mineral phases in basalts of theB. , 1975. Perched silia minerals on mordenite fibers. Jour.lt;. UC—70 I SECONDARY MINERALS FOUND IN CORES DC2 AI AND

  10. 0.7-eV GaInAs Junction for a GaInP/GaAs/GaInAs(1eV)/GaInAs(0.7eV) Four-Junction Solar Cell

    SciTech Connect (OSTI)

    Friedman, D. J.; Geisz, J. F.; Norman, A. G.; Wanlass, M. W.; Kurtz, S. R.

    2006-01-01

    We discuss recent developments in III-V multijunction solar cells, focusing on adding a fourth junction to the Ga{sub 0.5}In{sub 0.5} P/GaAs/Ga{sub 0.75}In{sub 0.25}As inverted three-junction cell. This cell, grown inverted on GaAs so that the lattice-mismatched Ga{sub 0.75}In{sub 0.25}As third junction is the last one grown, has demonstrated 38% efficiency, and 40% is likely in the near future. To achieve still further gains, a lower-bandgap Ga{sub x}In{sub 1-x}As fourth junction could be added to the three-junction structure for a four-junction cell whose efficiency could exceed 45% under concentration. Here, we present the initial development of the Ga{sub x}In{sub 1-x}As fourth junction. Junctions of various bandgaps ranging from 0.88 to 0.73 eV were grown, in order to study the effect of the different amounts of lattice mismatch. At a bandgap of 0.88 eV, junctions were obtained with very encouraging {approx}80% quantum efficiency, 57% fill factor, and 0.36 eV open-circuit voltage. The device performance degrades with decreasing bandgap (i.e., increasing lattice mismatch). We model the four-junction device efficiency vs. fourth junction bandgap to show that an 0.7-eV fourth-junction bandgap, while optimal if it could be achieved in practice, is not necessary; an 0.9-eV bandgap would still permit significant gains in multijunction cell efficiency while being easier to achieve than the lower-bandgap junction.

  11. Electron tunneling spectroscopy study of electrically active traps in AlGaN/GaN high electron mobility transistors

    SciTech Connect (OSTI)

    Yang, Jie Cui, Sharon; Ma, T. P.; Hung, Ting-Hsiang; Nath, Digbijoy; Krishnamoorthy, Sriram; Rajan, Siddharth

    2013-11-25

    We investigate the energy levels of electron traps in AlGaN/GaN high electron mobility transistors by the use of electron tunneling spectroscopy. Detailed analysis of a typical spectrum, obtained in a wide gate bias range and with both bias polarities, suggests the existence of electron traps both in the bulk of AlGaN and at the AlGaN/GaN interface. The energy levels of the electron traps have been determined to lie within a 0.5?eV band below the conduction band minimum of AlGaN, and there is strong evidence suggesting that these traps contribute to Frenkel-Poole conduction through the AlGaN barrier.

  12. A InGaN/GaN quantum dot green ({lambda}=524 nm) laser

    SciTech Connect (OSTI)

    Zhang Meng; Banerjee, Animesh; Lee, Chi-Sen; Hinckley, John M.; Bhattacharya, Pallab

    2011-05-30

    The characteristics of self-organized InGaN/GaN quantum dot lasers are reported. The laser heterostructures were grown on c-plane GaN substrates by plasma-assisted molecular beam epitaxy and the laser facets were formed by focused ion beam etching with gallium. Emission above threshold is characterized by a peak at 524 nm (green) and linewidth of 0.7 nm. The lowest measured threshold current density is 1.2 kA/cm{sup 2} at 278 K. The slope and wall plug efficiencies are 0.74 W/A and {approx}1.1%, respectively, at 1.3 kA/cm{sup 2}. The value of T{sub 0}=233 K in the temperature range of 260-300 K.

  13. Photocapacitance study of type-II GaSb/GaAs quantum ring solar cells

    SciTech Connect (OSTI)

    Wagener, M. C.; Botha, J. R.; Carrington, P. J.; Krier, A.

    2014-01-07

    In this study, the density of states associated with the localization of holes in GaSb/GaAs quantum rings are determined by the energy selective charging of the quantum ring distribution. The authors show, using conventional photocapacitance measurements, that the excess charge accumulated within the type-II nanostructures increases with increasing excitation energies for photon energies above 0.9?eV. Optical excitation between the localized hole states and the conduction band is therefore not limited to the ?(k?=?0) point, with pseudo-monochromatic light charging all states lying within the photon energy selected. The energy distribution of the quantum ring states could consequently be accurately related from the excitation dependence of the integrated photocapacitance. The resulting band of localized hole states is shown to be well described by a narrow distribution centered 407?meV above the GaAs valence band maximum.

  14. Efficiency enhancement of InGaN/GaN solar cells with nanostructures

    SciTech Connect (OSTI)

    Bai, J.; Yang, C. C.; Athanasiou, M.; Wang, T.

    2014-02-03

    We demonstrate InGaN/GaN multi-quantum-well solar cells with nanostructures operating at a wavelength of 520?nm. Nanostructures with a periodic nanorod or nanohole array are fabricated by means of modified nanosphere lithography. Under 1 sun air-mass 1.5 global spectrum illumination, a fill factor of 50 and an open circuit voltage of 1.9?V are achieved in spite of very high indium content in InGaN alloys usually causing degradation of crystal quality. Both the nanorod array and the nanohole array significantly improve the performance of solar cells, while a larger enhancement is observed for the nanohole array, where the conversion efficiency is enhanced by 51%.

  15. Graphene in ohmic contact for both n-GaN and p-GaN

    SciTech Connect (OSTI)

    Zhong, Haijian; Liu, Zhenghui; Shi, Lin; Xu, Gengzhao; Fan, Yingmin; Huang, Zengli [Suzhou Institute of Nano-Tech and Nano-Bionics, CAS, Suzhou 215123 (China); Wang, Jianfeng; Ren, Guoqiang; Xu, Ke, E-mail: kxu2006@sinano.ac.cn [Suzhou Institute of Nano-Tech and Nano-Bionics, CAS, Suzhou 215123 (China); Suzhou Nanowin Science and Technology Co., Ltd., Suzhou 215123 (China)

    2014-05-26

    The wrinkles of single layer graphene contacted with either n-GaN or p-GaN were found both forming ohmic contacts investigated by conductive atomic force microscopy. The local I–V results show that some of the graphene wrinkles act as high-conductive channels and exhibiting ohmic behaviors compared with the flat regions with Schottky characteristics. We have studied the effects of the graphene wrinkles using density-functional-theory calculations. It is found that the standing and folded wrinkles with zigzag or armchair directions have a tendency to decrease or increase the local work function, respectively, pushing the local Fermi level towards n- or p-type GaN and thus improving the transport properties. These results can benefit recent topical researches and applications for graphene as electrode material integrated in various semiconductor devices.

  16. Discharging a DC bus capacitor of an electrical converter system

    DOE Patents [OSTI]

    Kajouke, Lateef A; Perisic, Milun; Ransom, Ray M

    2014-10-14

    A system and method of discharging a bus capacitor of a bidirectional matrix converter of a vehicle are presented here. The method begins by electrically shorting the AC interface of the converter after an AC energy source is disconnected from the AC interface. The method continues by arranging a plurality of switching elements of a second energy conversion module into a discharge configuration to establish an electrical current path from a first terminal of an isolation module, through an inductive element, and to a second terminal of the isolation module. The method also modulates a plurality of switching elements of a first energy conversion module, while maintaining the discharge configuration of the second energy conversion module, to at least partially discharge a DC bus capacitor.

  17. Thermal cum DC Camouflage in Duet with Undecorated Natural Materials

    E-Print Network [OSTI]

    Yang, Tian-Zhi; Gao, Dongliang; Wu, Linzhi; Li, Baowen; Thong, John T L; Qiu, Cheng-Wei

    2015-01-01

    To manipulate various types of physical signals in one single device has long captivated the attention of scientists and engineers. This however is very challenging, if not impossible, even for emerging metamaterials. Up to date, many artificial materials have been proposed, theoretically and (or) experimentally, for manipulating various waves/signals on a one-function-one-device basis. In this work, for the very first time, we employ undecorated natural materials to experimentally demonstrate a simultaneous camouflage for thermal current and electric dc current on the same device. It demonstrates how ingenuity can overcome the limitations of natural material systems without the need for complex decoration to impart inhomogeneous and (or) anisotropic properties, which was previously considered impossible to accomplish except by using metamaterials.

  18. FLUXCAP: A flux-coupled ac/dc magnetizing device

    E-Print Network [OSTI]

    Gopman, Daniel B; Kent, Andrew D

    2012-01-01

    We report on an instrument for applying ac and dc magnetic fields by capturing the flux from a rotating permanent magnet and projecting it between two adjustable pole pieces. This can be an alternative to standard electromagnets for experiments with small samples or in probe stations in which an applied magnetic field is needed locally, with advantages that include a compact form-factor, very low power requirements and dissipation as well as fast field sweep rates. This flux capture instrument (FLUXCAP) can produce fields from -400 to +400 mT, with field resolution less than 1 mT. It generates static magnetic fields as well as ramped fields, with ramping rates as high as 10 T/s. We demonstrate the use of this apparatus for studying the magnetotransport properties of spin-valve nanopillars, a nanoscale device that exhibits giant magnetoresistance.

  19. Superconducting DC and RF Properties of Ingot Niobium

    SciTech Connect (OSTI)

    Pashupati Dhakal, Gianluigi Ciovati, Peter Kneisel, Ganapati Rao Myneni

    2011-07-01

    The thermal conductivity, DC magnetization and penetration depth of large-grain niobium hollow cylindrical rods fabricated from ingots, manufactured by CBMM subjected to chemical and heat treatment were measured. The results confirm the influence of chemical and heat-treatment processes on the superconducting properties, with no significant dependence on the impurity concentrations in the original ingots. Furthermore, RF properties, such as the surface resistance and quench field of the niobium rods were measured using a TE{sub 011} cavity. The hollow niobium rod is the center conductor of this cavity, converting it to a coaxial cavity. The quench field is limited by the critical heat flux through the rods' cooling channel.

  20. Possible temperature control DC switch effect between two superconductors

    E-Print Network [OSTI]

    Tian De Cao

    2011-08-11

    The lifetime of an electron pair could not be unlimited long, on the basis of this, we suggest a model. The model means that the movements of charge carriers in a superconductor should have three forms: the single-electron movement, the single-pair movement, and the revolving around the mass center of two electrons in a pair. Thus the current in a superconductor has three possible parts. Similarly, there should be three possible effects in a SIS junction: the tunneling of single electron, the tunneling of single pair, and the pair-forming following the pair-breaking. This paper will discuss these problems and present a possible temperature control DC switch effect between two superconductors.

  1. Multi-terminal Subsystem Model Validation for Pacific DC Intertie

    SciTech Connect (OSTI)

    Yang, Bo; Huang, Zhenyu; Kosterev, Dmitry

    2008-07-20

    this paper proposes to validate dynamic model of Pacific DC Intertie with the concept of hybrid simulation by combing simulation with PMU measurements. The Playback function available in GE PSLF is adopted for hybrid simulation. It is demonstrated for the first time the feasibility of using Playback function on multi-terminal subsystem. Sensitivity studies are also presented as a result of common PMU measurement quality problem, ie, offset noise and time synchronization. Results indicate a good tolerance of PDCI model generally. It is recommended that requirements should apply to phasor measurements in model validation work to ensure better analysis. Key parameters are identified based on impact of value change to model behavior. Two events are employed for preliminary model validation with PMU measurements. Suggestions are made for PDCI model validation work in the future.

  2. Effect of DC voltage pulses on memristor behavior.

    SciTech Connect (OSTI)

    Evans, Brian R.

    2013-10-01

    Current knowledge of memristor behavior is limited to a few physical models of which little comprehensive data collection has taken place. The purpose of this research is to collect data in search of exploitable memristor behavior by designing and implementing tests on a HP Labs Rev2 Memristor Test Board. The results are then graphed in their optimal format for conceptualizing behavioral patterns. This series of experiments has concluded the existence of an additional memristor state affecting the behavior of memristors when pulsed with positively polarized DC voltages. This effect has been observed across multiple memristors and data sets. The following pages outline the process that led to the hypothetical existence and eventual proof of this additional state of memristor behavior.

  3. Auxiliary quasi-resonant dc tank electrical power converter

    DOE Patents [OSTI]

    Peng, Fang Z.

    2006-10-24

    An auxiliary quasi-resonant dc tank (AQRDCT) power converter with fast current charging, voltage balancing (or charging), and voltage clamping circuits is provided for achieving soft-switched power conversion. The present invention is an improvement of the invention taught in U.S. Pat. No. 6,111,770, herein incorporated by reference. The present invention provides faster current charging to the resonant inductor, thus minimizing delay time of the pulse width modulation (PWM) due to the soft-switching process. The new AQRDCT converter includes three tank capacitors or power supplies to achieve the faster current charging and minimize the soft-switching time delay. The new AQRDCT converter further includes a voltage balancing circuit to charge and discharge the three tank capacitors so that additional isolated power supplies from the utility line are not needed. A voltage clamping circuit is also included for clamping voltage surge due to the reverse recovery of diodes.

  4. Materials with low DC magnetic susceptibility for sensitive magnetic measurements R. Khatiwada,1, 2, 3,

    E-Print Network [OSTI]

    Materials with low DC magnetic susceptibility for sensitive magnetic measurements R. Khatiwada,1, 2 (Dated: July 1, 2015) Materials with very low DC magnetic susceptibility have many scientific a totally nonmagnetic material. This phrase in our case means after spatially averaging over macroscopic

  5. Nonlinear Dust Acoustic Waves, Shocks and Stationary Structures in a DC Glow Discharge Dusty Plasma

    E-Print Network [OSTI]

    Merlino, Robert L.

    Nonlinear Dust Acoustic Waves, Shocks and Stationary Structures in a DC Glow Discharge Dusty Plasma drifting dusty plasmas and temporal dust acoustic wave growth Phys. Plasmas 18, 113706 (2011) Modulational;Nonlinear Dust Acoustic Waves, Shocks and Stationary Structures in a DC Glow Discharge Dusty Plasma Robert L

  6. DC WRRC Report No. 178 AN EXPERIMENTAL STUDY OF THE OPTIMAL THICKNESS OF A SAND

    E-Print Network [OSTI]

    District of Columbia, University of the

    FILTER WATER QUALITY STRUCTURE July 1994 D.C. Water Resources Research Center University of the District OF THE OPTIMAL THICKNESS OF A SAND LAYER IN A SAND FILTER WATER QUALITY STRUCTURE Submitted by: Farshad Amini THICKNESS OF A SAND LAYER IN A SAND FILTER WATER QUALITY STRUCTURE July 1994 D.C. Water Resources Research

  7. EE443L: Intermediate Control Lab Lab2: Modeling a DC motor

    E-Print Network [OSTI]

    Wedeward, Kevin

    EE443L: Intermediate Control Lab Lab2: Modeling a DC motor Introduction: In this lab we will develop and validate a basic model of a permanent magnet DC motor (Yaskawa Electric, Mini-series, Minertia motor). The specific input/output relationship, which we are interested in determining, is the manner

  8. www.sciencemag.org/cgi/content/full/342/6155/224/DC1 Supplementary Materials for

    E-Print Network [OSTI]

    McEuen, Paul L.

    www.sciencemag.org/cgi/content/full/342/6155/224/DC1 Supplementary Materials for Imaging Atomic the following: (available at www.sciencemag.org/cgi/content/full/342/6155/224/DC1) Movies S1 to S5 #12;2 Materials and Methods Transmission electron microscopy (TEM )Imaging Transmission electron microscopy (TEM

  9. Aalborg Universitet Intelligent DC Microgrid Living Laboratories -A Chinese-Danish Project

    E-Print Network [OSTI]

    Vasquez, Juan Carlos

    Aalborg Universitet Intelligent DC Microgrid Living Laboratories - A Chinese-Danish Project Diaz Microgrid Living Laboratories - A Chinese-Danish Project. In IEEE ICDCM 2015. IEEE Press. General rights.aau.dk on: juli 07, 2015 #12;Intelligent DC Microgrid Living Laboratories - A Chinese-Danish Project Enrique

  10. A Scalable DC Microgrid Architecture for Rural Electrification in Emerging Regions

    E-Print Network [OSTI]

    Sanders, Seth

    A Scalable DC Microgrid Architecture for Rural Electrification in Emerging Regions P. Achintya the design and experimental validation of a scalable dc microgrid architecture for rural electrification. The microgrid design has been driven by field data collected from Kenya and India. The salient features

  11. Aalborg Universitet Distributed Consensus-Based Control of Multiple DC-Microgrids Clusters

    E-Print Network [OSTI]

    Vasquez, Juan Carlos

    Aalborg Universitet Distributed Consensus-Based Control of Multiple DC-Microgrids Clusters Shafiee). Distributed Consensus-Based Control of Multiple DC-Microgrids Clusters. In Proceedings of the 40th Annual.aau.dk on: juli 05, 2015 #12;This document downloaded from www.microgrids.et.aau.dk is a preprint

  12. Zeroing Transformer's DC Current in Resonant Converters with No Series Capacitors

    E-Print Network [OSTI]

    Gertsman, Student Member, IEEE and Sam Ben-Yaakov ,Fellow, IEEE Power Electronics Laboratory Department: www.ee.bgu.ac.il/~pel Abstract - DC current unbalance in the windings of a transformer may initiate the transformer's DC current to zero by correcting the asymmetry of the drive. This balancing control

  13. Aalborg Universitet Distributed Bus Signaling Control for a DC Charging Station with Multi Paralleled

    E-Print Network [OSTI]

    Vasquez, Juan Carlos

    been reported in order to verify the validity of proposed approach. Keywords--EV charging; flywheelAalborg Universitet Distributed Bus Signaling Control for a DC Charging Station with Multi., & Savaghebi, M. (2015). Distributed Bus Signaling Control for a DC Charging Station with Multi Paralleled

  14. Genomic Plasticity Enables Phenotypic Variation of Pseudomonas syringae pv. tomato DC3000

    E-Print Network [OSTI]

    Myers, Chris

    Genomic Plasticity Enables Phenotypic Variation of Pseudomonas syringae pv. tomato DC3000 Zhongmeng of a genomic anomaly in the region of 4.7 to 4.9 Mb of the Pseudomonas syringae pv. tomato (Pst) DC3000 genome in P. syringae. Citation: Bao Z, Stodghill PV, Myers CR, Lam H, Wei H-L, et al. (2014) Genomic

  15. The Data Center (DC) Genome project is a collaborative effort with Microsoft Research

    E-Print Network [OSTI]

    Amir, Yair

    DC Genome The Data Center (DC) Genome project is a collaborative effort with Microsoft Research the efficiency of data center operations and thus minimize their environmental impact. Data center energy about carbon footprints and climate change. Lack of visibility into the data center's operating

  16. DC Discharge Studies Using PIC-MCC Jeff Hammel and John Verboncoeur

    E-Print Network [OSTI]

    Wurtele, Jonathan

    DC Discharge Studies Using PIC-MCC Jeff Hammel and John Verboncoeur March 31, 2004 1 Introduction (PIC-MCC) method. PIC-MCC is used to accurately model kinetic processes present in DC discharges PIC. Cross-validation of PIC-MCC simulation and analysis may be used to improved both computational

  17. D.C. Community Comes Together in the Name of Sustainability, Affordability

    Broader source: Energy.gov [DOE]

    The New School for Design and Stevens Institute of Technology 2011 Solar Decathlon team is partnering with D.C. community members and Habitat for Humanity to build an energy efficient home that will be moved to the Deanwood neighborhood of Washington, D.C. following the competition.

  18. Reid Rosnick/DC/USEPA/US 10/25/2012 11:54 AM

    E-Print Network [OSTI]

    Management and Regulations Washington, DC phone: 202-343-9186 email: egidi.philip@epa.gov cell: 970 Washington, DC phone: 202-343-9186 email: egidi.philip@epa.gov cell: 970-209-2885 Reid Rosnick---10! ------------------------------------------------------------------------------------------------------ -------- Reid J. Rosnick Radiation Protection Division (6608J) U.S. Environmental Protection Agency 1200

  19. Parametric Study of PV Arc-Fault Generation Methods and Analysis of Conducted DC Spectrum

    E-Print Network [OSTI]

    Parametric Study of PV Arc-Fault Generation Methods and Analysis of Conducted DC Spectrum Jay photovoltaic (PV) direct current (DC) arc- fault detectors use the frequency content of the PV system to detect by different PV arcs in the field. In this investigation, we (a) discuss the differences in establishing

  20. Temperature dependency of the emission properties from positioned In(Ga)As/GaAs quantum dots

    SciTech Connect (OSTI)

    Braun, T.; Schneider, C.; Maier, S.; Forchel, A.; Höfling, S.; Kamp, M.; Igusa, R.; Iwamoto, S.; Arakawa, Y.

    2014-09-15

    In this letter we study the influence of temperature and excitation power on the emission linewidth from site-controlled InGaAs/GaAs quantum dots grown on nanoholes defined by electron beam lithography and wet chemical etching. We identify thermal electron activation as well as direct exciton loss as the dominant intensity quenching channels. Additionally, we carefully analyze the effects of optical and acoustic phonons as well as close-by defects on the emission linewidth by means of temperature and power dependent micro-photoluminescence on single quantum dots with large pitches.

  1. Origins of ion irradiation-induced Ga nanoparticle motion on GaAs surfaces

    SciTech Connect (OSTI)

    Kang, M.; Wu, J. H.; Chen, H. Y.; Thornton, K.; Goldman, R. S. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States)] [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States); Sofferman, D. L. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States) [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136 (United States); Department of Physics, Adelphi University, Garden City, New York 11530-0701 (United States); Beskin, I. [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1040 (United States)] [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1040 (United States)

    2013-08-12

    We have examined the origins of ion irradiation-induced nanoparticle (NP) motion. Focused-ion-beam irradiation of GaAs surfaces induces random walks of Ga NPs, which are biased in the direction opposite to that of ion beam scanning. Although the instantaneous NP velocities are constant, the NP drift velocities are dependent on the off-normal irradiation angle, likely due to a difference in surface non-stoichiometry induced by the irradiation angle dependence of the sputtering yield. It is hypothesized that the random walks are initiated by ion irradiation-induced thermal fluctuations, with biasing driven by anisotropic mass transport.

  2. Adaptive Selective Harmonic Minimization Based on ANNs for Cascade Multilevel Inverters With Varying DC Sources

    SciTech Connect (OSTI)

    Filho, Faete [ORNL; Maia, Helder Z [UFMS, Department of Electrical Engineering; Mateus, Tiago Henrique D [ORNL; Ozpineci, Burak [ORNL; Tolbert, Leon M [ORNL; Pinto, Joao Onofre P [ORNL

    2013-01-01

    A new approach for modulation of an 11-level cascade multilevel inverter using selective harmonic elimination is presented in this paper. The dc sources feeding the multilevel inverter are considered to be varying in time, and the switching angles are adapted to the dc source variation. This method uses genetic algorithms to obtain switching angles offline for different dc source values. Then, artificial neural networks are used to determine the switching angles that correspond to the real-time values of the dc sources for each phase. This implies that each one of the dc sources of this topology can have different values at any time, but the output fundamental voltage will stay constant and the harmonic content will still meet the specifications. The modulating switching angles are updated at each cycle of the output fundamental voltage. This paper gives details on the method in addition to simulation and experimental results.

  3. GaN based nanorods for solid state lighting

    SciTech Connect (OSTI)

    Li Shunfeng; Waag, Andreas [Institute of Semiconductor Technology, Braunschweig University of Technology, 38106 Braunschweig (Germany)

    2012-04-01

    In recent years, GaN nanorods are emerging as a very promising novel route toward devices for nano-optoelectronics and nano-photonics. In particular, core-shell light emitting devices are thought to be a breakthrough development in solid state lighting, nanorod based LEDs have many potential advantages as compared to their 2 D thin film counterparts. In this paper, we review the recent developments of GaN nanorod growth, characterization, and related device applications based on GaN nanorods. The initial work on GaN nanorod growth focused on catalyst-assisted and catalyst-free statistical growth. The growth condition and growth mechanisms were extensively investigated and discussed. Doping of GaN nanorods, especially p-doping, was found to significantly influence the morphology of GaN nanorods. The large surface of 3 D GaN nanorods induces new optical and electrical properties, which normally can be neglected in layered structures. Recently, more controlled selective area growth of GaN nanorods was realized using patterned substrates both by metalorganic chemical vapor deposition (MOCVD) and by molecular beam epitaxy (MBE). Advanced structures, for example, photonic crystals and DBRs are meanwhile integrated in GaN nanorod structures. Based on the work of growth and characterization of GaN nanorods, GaN nanoLEDs were reported by several groups with different growth and processing methods. Core/shell nanoLED structures were also demonstrated, which could be potentially useful for future high efficient LED structures. In this paper, we will discuss recent developments in GaN nanorod technology, focusing on the potential advantages, but also discussing problems and open questions, which may impose obstacles during the future development of a GaN nanorod based LED technology.

  4. Narrating Washington, D.C. from the Margins: Urban Space and Cultural Identity in "Lost in the City" and "The Beautiful Things that Heaven Bears"

    E-Print Network [OSTI]

    Brown, Jessica M

    2011-01-01

    and Urban Space in Washington, D.C. Chicago: University ofBrookings Institution. Washington, D.C. Gillette, Howard Jr.of Urban Policy in Washington, D.C. (2006). Baltimore: The

  5. Proceedings of WindPower 95, AWEA, Washington, D.C., 1995. FATIGUE DAMAGE ESTIMATE COMPARISONS FOR

    E-Print Network [OSTI]

    Proceedings of WindPower 95, AWEA, Washington, D.C., 1995. FATIGUE DAMAGE ESTIMATE COMPARISONS," Proceedings of WindPower `95, AWEA, Washington, DC, March, 1995, pp. 177-186. * This work is supported

  6. Insertion sequence 5 at various upstream locations of the flhDC operon causes Escherichia coli hyper motility

    E-Print Network [OSTI]

    Wang, Jing

    2010-01-01

    locations of the flhDC operon causes Escherichia coli Hyperlocations of the PflhDC operon causes Escherichia coli Hyperof the transposing segment causes the formation of co-

  7. GaInP/GaAs dual junction solar cells on Ge/Si epitaxial templates Melissa J. Archer,1,a

    E-Print Network [OSTI]

    Atwater, Harry

    GaInP/GaAs dual junction solar cells on Ge/Si epitaxial templates Melissa J. Archer,1,a Daniel C, crack-free GaInP/GaAs double junction solar cells were grown by metal organic chemical vapor deposition with the world record efficiency is a metamorphic triple junction GaInP/GaAs/Ge cell.6 Alternatively, wafer

  8. Enhanced hole transport in InGaN/GaN multiple quantum well light-emitting

    E-Print Network [OSTI]

    Demir, Hilmi Volkan

    -emitting diodes (LEDs) are considered the new generation lighting sources due to their advantages in power Society of America OCIS codes: 230.3670, 230.5590, 160.6000. Nitride-based high-power light devoted to the development of high-brightness GaN-based LEDs [3­5]. Lateral hole spreading is one

  9. High-Efficiency GaInP/GaAs Tandem Solar Cells

    SciTech Connect (OSTI)

    Bertness, K. A.; Friedman, D. J.; Kurtz, S. R.; Kibbler, A. E.; Cramer, C.; Olson, J. M.

    1996-09-01

    GaInP/GaAs tandem solar cells have achieved efficiencies between 25.7-30.2%, depending on illumination conditions. The efficiencies are the highest confirmed two-terminal values measured for any solar cell within each standard illumination category. The monolithic, series-connected design of the tandem cells allows them to be substituted for silicon or gallium arsenide cells in photovoltaic panel systems with minimal design changes. The advantages of using GaInP/GaAs tandem solar cells in space and terrestrial applications are discussed primarily in terms of the reduction in balance-of-system costs that accrues when using a higher efficiency cell. The new efficiency values represent a significant improvement over previous efficiencies for this materials system, and we identify grid design, back interface passivation, and top interface passivation as the three key factors leading to this improvement. In producing the high-efficiency cells, we have addressed nondestructive diagnostics and materials growth reproducibility as well as peak cell performance.

  10. High-efficiency GaInP/GaAs tandem solar cells

    SciTech Connect (OSTI)

    Bertness, K.A.; Friedman, D.J.; Kurtz, S.R.; Kibbler, A.E.; Kramer, C.; Olson, J.M.

    1994-12-01

    GaInP/GaAs tandem solar cells have achieved new record efficiencies, specifically 25.7% under air-mass 0 (AM0) illumination, 29.5% under AM 1.5 global (AM1.5G) illumination, and 30.2% at 140-180x concentration under AM 1.5 direct (AM1.5D) illumination. These values are the highest two-terminal efficiencies achieved by any solar cell under these illumination conditions. The monolithic, series-connected design of the tandem cells allows them to be substituted for silicon or gallium arsenide cells in photovoltaic panel systems with minimal design changes. The advantages of using GaInP/GaAs tandem solar cells in space and terrestrial applications are discussed primarily in terms of the reduction in balance-of-system costs that accrues when using a higher efficiency cell. The new efficiency values represent a significant improvement over previous efficiencies for this materials system, and we identify grid design, back interface passivation, and top interface passivation as the three key factors leading to this improvement. In producing the high-efficiency cells, we have addressed nondestructive diagnostics and materials growth reproducibility as well as peak cell performance. 31 refs.

  11. TJ Solar Cell (GaInP/GaAs/Ge Ultrahigh-Efficiency Solar Cells

    SciTech Connect (OSTI)

    Friedman, Daniel

    2002-04-17

    This talk will discuss recent developments in III-V multijunction photovoltaic technology which have led to the highest-efficiency solar cells ever demonstrated. The relationship between the materials science of III-V semiconductors and the achievement of record solar cell efficiencies will be emphasized. For instance, epitaxially-grown GAInP has been found to form a spontaneously-ordered GaP/InP (111) superlattice. This ordering affects the band gap of the material, which in turn affects the design of solar cells which incorporate GaInP. For the next generation of ultrahigh-efficiency III-V solar cells, we need a new semiconductor which is lattice-matched to GaAs, has a band gap of 1 eV, and has long minority-carrier diffusion lengths. Out of a number of candidate materials, the recently-discovered alloy GaInNAs appears to have the greatest promise. This material satisfies the first two criteria, but has to date shown very low diffusion lengths, a problem which is our current focus in the development of these next-generation cells.

  12. Multijunction GaInP/GaInAs/Ge solar cells with Bragg reflectors

    SciTech Connect (OSTI)

    Emelyanov, V. M. Kalyuzhniy, N. A.; Mintairov, S. A.; Shvarts, M. Z.; Lantratov, V. M.

    2010-12-15

    Effect of subcell parameters on the efficiency of GaInP/Ga(In)As/Ge tandem solar cells irradiated with 1-MeV electrons at fluences of up to 3 x 10{sup 15} cm{sup -2} has been theoretically studied. The optimal thicknesses of GaInP and GaInAs subcells, which provide the best photocurrent matching at various irradiation doses in solar cells with and without built-in Bragg reflectors, were determined. The dependences of the photoconverter efficiency on the fluence of 1-MeV electrons and on the time of residence in the geostationary orbit were calculated for structures optimized to the beginning and end of their service lives. It is shown that the optimization of the subcell heterostructures for a rated irradiation dose and the introduction of Bragg reflectors into the structure provide a 5% overall increase in efficiency for solar cells operating in the orbit compared with unoptimized cells having no Bragg reflector.

  13. Localized corrosion of GaAs surfaces and formation of porous GaAs

    SciTech Connect (OSTI)

    Schmuki, P.; Vitus, C.M.; Isaacs, H.S.; Fraser, J.; Graham, M.J.

    1995-12-01

    The present work deals with pitting corrosion of p- and n-type GaAs (100). Pit growth can be electrochemically initiated on both conduction types in chloride-containing solutions and leads after extended periods of time to the formation of a porous GaAs structure. In the case of p-type material, localized corrosion is only observed if a passivating film is present on the surface, otherwise -- e.g. in acidic solutions -- the material suffers from a uniform attack (electropolishing) which is independent of the anion present. In contrast, pitting corrosion of n-type material can be triggered independent of the presence of an oxide film. This is explained in terms of the different current limiting factor for the differently doped materials (oxide film in the case of the p- and a space charge layer in the case of the n-GaAs). The porous structure was characterized by SEM, EDX and AES, and consists mainly of GaAs. From scratch experiments it is clear that the pit initiation process is strongly influenced by surface defects. For n-type material, AFM investigations show that light induced roughening of the order of several hundred nm occurs under non-passivating conditions. This nm- scale roughening however does not affect the pitting process.

  14. Demonstration of a semipolar (10(1)over-bar(3)over-bar) InGaN/GaN green light emitting diode

    E-Print Network [OSTI]

    2005-01-01

    InGaN / GaN green light emitting diode R. Sharma, a? P. M.green ??525 nm? light emitting diode ?LED?. The fabricated

  15. 1620 IEEE TRANSACTIONS ON POWER DELIVERY, VOL. 27, NO. 3, JULY 2012 Hybrid AC/DC Transmission Expansion Planning

    E-Print Network [OSTI]

    Fu, Yong

    1620 IEEE TRANSACTIONS ON POWER DELIVERY, VOL. 27, NO. 3, JULY 2012 Hybrid AC/DC Transmission--This paper proposes a hybrid algorithm for the ac/dc transmission expansion planning (TEP). The stochastic simulation method would consider random outages of generating units and ac/dc transmission lines as well

  16. Deep level defects in n-type GaAsBi and GaAs grown at low temperatures

    SciTech Connect (OSTI)

    Mooney, P. M.; Watkins, K. P.; Jiang, Zenan; Basile, A. F.; Lewis, R. B.; Bahrami-Yekta, V.; Masnadi-Shirazi, M.; Beaton, D. A.; Tiedje, T.

    2013-04-07

    Deep level defects in n-type GaAs{sub 1-x}Bi{sub x} having 0 < x < 0.012 and GaAs grown by molecular beam epitaxy (MBE) at substrate temperatures between 300 and 400 Degree-Sign C have been investigated by Deep Level Capacitance Spectroscopy. Incorporating Bi suppresses the formation of an electron trap with activation energy 0.40 eV, thus reducing the total trap concentration in dilute GaAsBi layers by more than a factor of 20 compared to GaAs grown under the same conditions. We find that the dominant traps in dilute GaAsBi layers are defect complexes involving As{sub Ga}, as expected for MBE growth at these temperatures.

  17. High efficiency InGaN/GaN light emitting diodes with asymmetric triangular multiple quantum wells

    SciTech Connect (OSTI)

    Chang, Chiao-Yun; Li, Hen; Lu, Tien-Chang, E-mail: timtclu@mail.nctu.edu.tw [Department of Photonics and Institute of Electro-Optical Engineering, National Chiao Tung University, 1001 University Road, Hsinchu, Taiwan 300 (China)

    2014-03-03

    In this study, we demonstrated high efficiency InGaN/GaN light emitting diodes (LEDs) with asymmetric triangular multiple quantum wells (MQWs). Asymmetric triangular MQWs not only contribute to uniform carrier distribution in InGaN/GaN MQWs but also yield a low Auger recombination rate. In addition, asymmetric triangular MQWs with gallium face-oriented inclination band profiles can be immune from the polarization charge originating from typical c-plane InGaN/GaN quantum well structures. In the experiment, LEDs incorporated with asymmetric triangular MQWs with gallium face-oriented inclination band profiles exhibited a 60.0% external quantum efficiency at 20?mA and a 27.0% efficiency droop at 100?mA (corresponding to a current density of 69?A/cm{sup 2}), which accounted for an 11.7% efficiency improvement and a 31.1% droop reduction compared with symmetric square quantum well structure LEDs.

  18. Deep level centers and their role in photoconductivity transients of InGaAs/GaAs quantum dot chains

    SciTech Connect (OSTI)

    Kondratenko, S. V. Vakulenko, O. V.; Mazur, Yu. I. Dorogan, V. G.; Marega, E.; Benamara, M.; Ware, M. E.; Salamo, G. J.

    2014-11-21

    The in-plane photoconductivity and photoluminescence are investigated in quantum dot-chain InGaAs/GaAs heterostructures. Different photoconductivity transients resulting from spectrally selecting photoexcitation of InGaAs QDs, GaAs spacers, or EL2 centers were observed. Persistent photoconductivity was observed at 80?K after excitation of electron-hole pairs due to interband transitions in both the InGaAs QDs and the GaAs matrix. Giant optically induced quenching of in-plane conductivity driven by recharging of EL2 centers is observed in the spectral range from 0.83?eV to 1.0?eV. Conductivity loss under photoexcitation is discussed in terms of carrier localization by analogy with carrier distribution in disordered media.

  19. Au impact on GaAs epitaxial growth on GaAs (111){sub B} substrates in molecular beam epitaxy

    SciTech Connect (OSTI)

    Liao, Zhi-Ming; Chen, Zhi-Gang; Xu, Hong-Yi; Guo, Ya-Nan; Sun, Wen; Zhang, Zhi; Yang, Lei; Lu, Zhen-Yu; Chen, Ping-Ping; Lu, Wei; Zou, Jin; Centre for Microscopy and Microanalysis, The University of Queensland, St. Lucia, Queensland 4072

    2013-02-11

    GaAs growth behaviour under the presence of Au nanoparticles on GaAs {l_brace}111{r_brace}{sub B} substrate is investigated using electron microscopy. It has been found that, during annealing, enhanced Ga surface diffusion towards Au nanoparticles leads to the GaAs epitaxial growth into {l_brace}113{r_brace}{sub B} faceted triangular pyramids under Au nanoparticles, governed by the thermodynamic growth, while during conventional GaAs growth, growth kinetics dominates, resulting in the flatted triangular pyramids at high temperature and the epitaxial nanowires growth at relatively low temperature. This study provides an insight of Au nanoparticle impact on GaAs growth, which is critical for understanding the formation mechanisms of semiconductor nanowires.

  20. An inverted AlGaAs/GaAs patterned-Ge tunnel junction cascade concentrator solar cell

    SciTech Connect (OSTI)

    Venkatasubramanian, R. )

    1993-01-01

    This report describes work to develop inverted-grown Al[sub 0.34]Ga[sub 0.66]As/GaAs cascades. Several significant developments are reported on as follows: (1) The AM1.5 1-sun total-area efficiency of the top Al[sub 0.34]Ga[sub 0.66]As cell for the cascade was improved from 11.3% to 13.2% (NREL measurement [total-area]). (2) The cycled'' organometallic vapor phase epitaxy growth (OMVPE) was studied in detail utilizing a combination of characterization techniques including Hall-data, photoluminescence, and secondary ion mass spectroscopy. (3) A technique called eutectic-metal-bonding (EMB) was developed by strain-free mounting of thin GaAs-AlGaAs films (based on lattice-matched growth on Ge substrates and selective plasma etching of Ge substrates) onto Si carrier substrates. Minority-carrier lifetime in an EMB GaAs double-heterostructure was measured as high as 103 nsec, the highest lifetime report for a freestanding GaAs thin film. (4) A thin-film, inverted-grown GaAs cell with a 1-sun AM1.5 active-area efficiency of 20.3% was obtained. This cell was eutectic-metal-bonded onto Si. (5) A thin-film inverted-grown, Al[sub 0.34]Ga[sub 0.66]As/GaAs cascade with AM1.5 efficiency of 19.9% and 21% at 1-sun and 7-suns, respectively, was obtained. This represents an important milestone in the development of an AlGaAs/GaAs cascade by OMVPE utilizing a tunnel interconnect and demonstrates a proof-of-concept for the inverted-growth approach.

  1. The Effect of the Thermal Boundary Resistance on Self-Heating of AlGaN/GaN HFETs

    E-Print Network [OSTI]

    sound velocity in GaN. The cut off wave vector is given by where NA is the Avogadro number, is the mass

  2. 154 Solutions Manual x Fluid Mechanics, Fifth Edition Solution: First, how high is the container? Well, 1 fluid oz. 1.805 in3, hence 12 fl. oz.

    E-Print Network [OSTI]

    Bahrami, Majid

    154 Solutions Manual x Fluid Mechanics, Fifth Edition Solution: First, how high is the container? Well, 1 fluid oz. 1.805 in3, hence 12 fl. oz. 21.66 in3 S(1.5 in)2h, or h | 3.06 in--It is a fat S (1.5 in)2(2.77 in) 19.6 in3 | 10.8 fluid oz. Ans. 2.139 The tank of liquid in the figure P2

  3. Quercetin 3-O-methyl ether protects FL83B cells from copper induced oxidative stress through the PI3K/Akt and MAPK/Erk pathway

    SciTech Connect (OSTI)

    Tseng, Hsiao-Ling, E-mail: lily1001224@gmail.com [Department of Life Sciences, Tzu Chi University, Hualien, Taiwan (China)] [Department of Life Sciences, Tzu Chi University, Hualien, Taiwan (China); Li, Chia-Jung, E-mail: 97751101@stmail.tcu.edu.tw [Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan (China)] [Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan (China); Huang, Lin-Huang, E-mail: yg1236@yahoo.com.tw [School of Medicine, Institute of Traditional Medicine, National Yang-Ming University, Taipei, Taiwan (China)] [School of Medicine, Institute of Traditional Medicine, National Yang-Ming University, Taipei, Taiwan (China); Chen, Chun-Yao, E-mail: cychen@mail.tcu.edu.tw [Department of Life Sciences, Tzu Chi University, Hualien, Taiwan (China)] [Department of Life Sciences, Tzu Chi University, Hualien, Taiwan (China); Tsai, Chun-Hao, E-mail: 100726105@stmail.tcu.edu.tw [Department of Life Sciences, Tzu Chi University, Hualien, Taiwan (China)] [Department of Life Sciences, Tzu Chi University, Hualien, Taiwan (China); Lin, Chun-Nan, E-mail: lincna@cc.kmu.edu.tw [Faculty of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan (China) [Faculty of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Kaohsiung, Taiwan (China); Department of Biological Science and Technology, School of Medicine, China Medical University, Taichung, Taiwan (China); Hsu, Hsue-Yin, E-mail: hsueyin@mail.tcu.edu.tw [Department of Life Sciences, Tzu Chi University, Hualien, Taiwan (China)] [Department of Life Sciences, Tzu Chi University, Hualien, Taiwan (China)

    2012-10-01

    Quercetin is a bioflavonoid that exhibits several biological functions in vitro and in vivo. Quercetin 3-O-methyl ether (Q3) is a natural product reported to have pharmaceutical activities, including antioxidative and anticancer activities. However, little is known about the mechanism by which it protects cells from oxidative stress. This study was designed to investigate the mechanisms by which Q3 protects against Cu{sup 2+}-induced cytotoxicity. Exposure to Cu{sup 2+} resulted in the death of mouse liver FL83B cells, characterized by apparent apoptotic features, including DNA fragmentation and increased nuclear condensation. Q3 markedly suppressed Cu{sup 2+}-induced apoptosis and mitochondrial dysfunction, characterized by reduced mitochondrial membrane potential, caspase-3 activation, and PARP cleavage, in Cu{sup 2+}-exposed cells. The involvement of PI3K, Akt, Erk, FOXO3A, and Mn-superoxide dismutase (MnSOD) was shown to be critical to the survival of Q3-treated FL83B cells. The liver of both larval and adult zebrafish showed severe damage after exposure to Cu{sup 2+} at a concentration of 5 ?M. Hepatic damage induced by Cu{sup 2+} was reduced by cotreatment with Q3. Survival of Cu{sup 2+}-exposed larval zebrafish was significantly increased by cotreatment with 15 ?M Q3. Our results indicated that Cu{sup 2+}-induced apoptosis in FL83B cells occurred via the generation of ROS, upregulation and phosphorylation of Erk, overexpression of 14-3-3, inactivation of Akt, and the downregulation of FOXO3A and MnSOD. Hence, these results also demonstrated that Q3 plays a protective role against oxidative damage in zebrafish liver and remarked the potential of Q3 to be used as an antioxidant for hepatocytes. Highlights: ? Protective effects of Q3 on Cu{sup 2+}-induced oxidative stress in vitro and in vivo. ? Cu{sup 2+} induced apoptosis in FL83B cells via ROS and the activation of Erk. ? Q3 abolishes Cu{sup 2+}-induced apoptosis through the PI3K/Akt and MAPK/Erk pathway.

  4. Reliability of AlGaN/GaN high electron mobility transistors on low dislocation density bulk GaN substrate: Implications of surface step edges

    SciTech Connect (OSTI)

    Killat, N., E-mail: Nicole.Killat@bristol.ac.uk, E-mail: Martin.Kuball@bristol.ac.uk; Montes Bajo, M.; Kuball, M., E-mail: Nicole.Killat@bristol.ac.uk, E-mail: Martin.Kuball@bristol.ac.uk [Center for Device Thermography and Reliability (CDTR), H.H. Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Paskova, T. [Kyma Technologies, Inc., Raleigh, North Carolina 27617 (United States) [Kyma Technologies, Inc., Raleigh, North Carolina 27617 (United States); Materials Science and Engineering Department, North Carolina State University, Raleigh, North Carolina 27695 (United States); Evans, K. R. [Kyma Technologies, Inc., Raleigh, North Carolina 27617 (United States)] [Kyma Technologies, Inc., Raleigh, North Carolina 27617 (United States); Leach, J. [Kyma Technologies, Inc., Raleigh, North Carolina 27617 (United States) [Kyma Technologies, Inc., Raleigh, North Carolina 27617 (United States); Electrical and Computer Engineering Department, Virginia Commonwealth University, Richmond, Virginia 23284 (United States); Li, X.; Özgür, Ü.; Morkoç, H. [Electrical and Computer Engineering Department, Virginia Commonwealth University, Richmond, Virginia 23284 (United States)] [Electrical and Computer Engineering Department, Virginia Commonwealth University, Richmond, Virginia 23284 (United States); Chabak, K. D.; Crespo, A.; Gillespie, J. K.; Fitch, R.; Kossler, M.; Walker, D. E.; Trejo, M.; Via, G. D.; Blevins, J. D. [Air Force Research Laboratory, Wright-Patterson Air Force Base, Dayton, Ohio 45433 (United States)] [Air Force Research Laboratory, Wright-Patterson Air Force Base, Dayton, Ohio 45433 (United States)

    2013-11-04

    To enable gaining insight into degradation mechanisms of AlGaN/GaN high electron mobility transistors, devices grown on a low-dislocation-density bulk-GaN substrate were studied. Gate leakage current and electroluminescence (EL) monitoring revealed a progressive appearance of EL spots during off-state stress which signify the generation of gate current leakage paths. Atomic force microscopy evidenced the formation of semiconductor surface pits at the failure location, which corresponds to the interaction region of the gate contact edge and the edges of surface steps.

  5. DC switching regulated power supply for driving an inductive load

    DOE Patents [OSTI]

    Dyer, George R. (Norris, TN)

    1986-01-01

    A power supply for driving an inductive load current from a dc power supply hrough a regulator circuit including a bridge arrangement of diodes and switching transistors controlled by a servo controller which regulates switching in response to the load current to maintain a selected load current. First and second opposite legs of the bridge are formed by first and second parallel-connected transistor arrays, respectively, while the third and fourth legs of the bridge are formed by appropriately connected first and second parallel connected diode arrays, respectively. The regulator may be operated in three "stages" or modes: (1) For current runup in the load, both first and second transistor switch arrays are turned "on" and current is supplied to the load through both transistor arrays. (2) When load current reaches the desired level, the first switch is turned "off", and load current "flywheels" through the second switch array and the fourth leg diode array connecting the second switch array in series with the load. Current is maintained by alternating between modes 1 and 2 at a suitable duty cycle and switching rate set by the controller. (3) Rapid current rundown is accomplished by turning both switch arrays "off", allowing load current to be dumped back into the source through the third and fourth diode arrays connecting the source in series opposition with the load to recover energy from the inductive load. The three operating states are controlled automatically by the controller.

  6. A Very Low-Luminosity, Very Cool, DC White Dwarf

    E-Print Network [OSTI]

    Hugh Harris; Conard Dahn; Frederick Vrba; Arne Henden; James Liebert; Gary Schmidt; Neill Reid

    1999-06-03

    The star LHS 3250 is found to be a white dwarf at a distance of 30 pc. Its absolute magnitudes (M_V = 15.72; M_bol = 16.2) put it among the least-luminous white dwarfs known. Its optical spectrum shows no features, indicating it has a DC classification, and it shows no detectable polarization, indicating it does not have a very strong magnetic field. However, its broadband colors show it to have a unique spectral energy distribution, and it stands out from all other stars in BVI and other broadband photometric surveys. We discuss these properties, and conclude that LHS 3250 must be an extremely cool white dwarf with strong collision-induced absorption at red-infrared wavelengths from molecular hydrogen, in accord with models for very cool white dwarf atmospheres. If so, it is the first such star known, and the first star to provide observational evidence supporting these models. It suggests that other very cool white dwarfs, both halo white dwarfs and the oldest disk white dwarfs, also may have colors affected by similar absorption. The atmospheric composition of LHS 3250 is not known, and therefore its temperature is poorly determined. It may be a helium-core star with a mass 0.3-0.45 M_solar and a product of mass-transfer in a close binary system. However, until its temperature is better known, its mass and age remain uncertain.

  7. Electrical and Optical Gain Lever Effects in InGaAs Double Quantum Well Diode Lasers

    SciTech Connect (OSTI)

    Pocha, M D; Goddard, L L; Bond, T C; Nikolic, R J; Vernon, S P; Kallman, J S; Behymer, E M

    2007-01-03

    In multisection laser diodes, the amplitude or frequency modulation (AM or FM) efficiency can be improved using the gain lever effect. To study gain lever, InGaAs double quantum well (DQW) edge emitting lasers have been fabricated with integrated passive waveguides and dual sections providing a range of split ratios from 1:1 to 9:1. Both the electrical and the optical gain lever have been examined. An electrical gain lever with greater than 7 dB enhancement of AM efficiency was achieved within the range of appropriate DC biasing currents, but this gain dropped rapidly outside this range. We observed a 4 dB gain in the optical AM efficiency under non-ideal biasing conditions. This value agreed with the measured gain for the electrical AM efficiency under similar conditions. We also examined the gain lever effect under large signal modulation for digital logic switching applications. To get a useful gain lever for optical gain quenched logic, a long control section is needed to preserve the gain lever strength and a long interaction length between the input optical signal and the lasing field of the diode must be provided. The gain lever parameter space has been fully characterized and validated against numerical simulations of a semi-3D hybrid beam propagation method (BPM) model for the coupled electron-photon rate equation. We find that the optical gain lever can be treated using the electrical injection model, once the absorption in the sample is known.

  8. FL J. Smith, Jr.

    Office of Legacy Management (LM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefield Municipal Gas &SCE-SessionsSouth DakotaRobbins and Myers CoMadison -T:..) ".. _,;$,byFIleact.

  9. Istanbul,Turkey & Atlanta, GA Istanbul,Turkey

    E-Print Network [OSTI]

    Frantz, Kyle J.

    Istanbul,Turkey & Atlanta, GA Istanbul,Turkey & Atlanta, GA 2012 Media, Journalism and Business for departure to Istanbul,Turkey Day 9 Depart for Istanbul; guided cultural visit upon arrival; group dinner Day business leaders; site visits to local universities Day 18 UPS and the value of logistics inTurkey Day 19

  10. Photoeffects in WO{sub 3}/GaAs electrode

    SciTech Connect (OSTI)

    Yoon, K.H.; Lee, J.W.; Cho, Y.S.; Kang, D.H.

    1996-12-01

    Photoeffects of a {ital p}-type GaAs coated with WO{sub 3} thin film have been investigated as a function of film thickness and photoresponse transients of the WO{sub 3}/GaAs electrode were studied. Also, these results were compared to those for a single {ital p}-type GaAs electrode. The photocurrent of the WO{sub 3}/GaAs electrode depended on the film thickness of the WO{sub 3}, showing an optimum photon efficiency for specimens of 800 A thickness. This is due to the existence of an effective interface state within the band gap which reduces trapping of carriers and facilitates carrier movement. For an 800-A-thick WO{sub 3} thin film deposited {ital p}-GaAs photoelectrode, the photogenerated electrons were found to move to an electrolyte at a higher positive onset potential compared with that of single {ital p}-type GaAs, which was confirmed as a result of transient behavior. {ital I}{endash}{ital V} and {ital C}{endash}{ital V} characteristics of the WO{sub 3}/GaAs electrode were also compared with those of a single {ital p}-type GaAs electrode. {copyright} {ital 1996 American Institute of Physics.}

  11. Room temperature spin transport in undoped (110) GaAs/AlGaAs quantum wells

    SciTech Connect (OSTI)

    Yokota, Nobuhide Aoshima, Yohei; Ikeda, Kazuhiro; Kawaguchi, Hitoshi

    2014-02-17

    We are reporting on our first observation of a micrometer-order electron spin transport in a (110) GaAs/AlGaAs multiple quantum well (QW) at room temperature using a space- and time-resolved Kerr rotation technique. A 37-?m transport was observed within an electron spin lifetime of 1.2?ns at room temperature when using an in-plane electric field of 1.75?kV/cm. The spatio-temporal profiles of electron spins were well reproduced by the spin drift-diffusion equations coupled with the Poisson equation, supporting the validity of the measurement. The results suggest that (110) QWs are useful as a spin transport layer for semiconductor spintronic devices operating at room temperature.

  12. Evaluation of the two-photon absorption characteristics of GaSb/GaAs quantum rings

    SciTech Connect (OSTI)

    Wagener, M. C.; Botha, J. R.; Carrington, P. J.; Krier, A.

    2014-07-28

    The optical parameters describing the sub-bandgap response of GaSb/GaAs quantum rings solar cells have been obtained from photocurrent measurements using a modulated pseudo-monochromatic light source in combination with a second, continuous photo-filling source. By controlling the charge state of the quantum rings, the photoemission cross-sections describing the two-photon sub-bandgap transitions could be determined independently. Temperature dependent photo-response measurements also revealed that the barrier for thermal hole emission from the quantum rings is significantly below the quantum ring localisation energy. The temperature dependence of the sub-bandgap photo-response of the solar cell is also described in terms of the photo- and thermal-emission characteristics of the quantum rings.

  13. Sidewall passivation for InGaN/GaN nanopillar light emitting diodes

    SciTech Connect (OSTI)

    Choi, Won Hyuck; Abraham, Michael; Yu, Shih-Ying [Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); You, Guanjun; Liu, Jie; Wang, Li; Xu, Jian, E-mail: jianxu@engr.psu.edu [Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Mohney, Suzanne E., E-mail: mohney@ems.psu.edu [Department of Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

    2014-07-07

    We studied the effect of sidewall passivation on InGaN/GaN multiquantum well-based nanopillar light emitting diode (LED) performance. In this research, the effects of varying etch rate, KOH treatment, and sulfur passivation were studied for reducing nanopillar sidewall damage and improving device efficiency. Nanopillars prepared under optimal etching conditions showed higher photoluminescence intensity compared with starting planar epilayers. Furthermore, nanopillar LEDs with and without sulfur passivation were compared through electrical and optical characterization. Suppressed leakage current under reverse bias and four times higher electroluminescence (EL) intensity were observed for passivated nanopillar LEDs compared with unpassivated nanopillar LEDs. The suppressed leakage current and EL intensity enhancement reflect the reduction of non-radiative recombination at the nanopillar sidewalls. In addition, the effect of sulfur passivation was found to be very stable, and further insight into its mechanism was gained through transmission electron microscopy.

  14. Large linear magnetoresistance in a GaAs/AlGaAs heterostructure

    SciTech Connect (OSTI)

    Aamir, Mohammed Ali, E-mail: aamir@physics.iisc.ernet.in; Goswami, Srijit, E-mail: aamir@physics.iisc.ernet.in; Ghosh, Arindam [Department of Physics, Indian Institute of Science, Bangalore 560 012 (India); Baenninger, Matthias; Farrer, Ian; Ritchie, David A. [Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Tripathi, Vikram [Department of Theoretical Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 (India); Pepper, Michael [Department of Electrical and Electronic Engineering, University College, London WC1E 7JE (United Kingdom)

    2013-12-04

    We report non-saturating linear magnetoresistance (MR) in a two-dimensional electron system (2DES) at a GaAs/AlGaAs heterointerface in the strongly insulating regime. We achieve this by driving the gate voltage below the pinch-off point of the device and operating it in the non-equilibrium regime with high source-drain bias. Remarkably, the magnitude of MR is as large as 500% per Tesla with respect to resistance at zero magnetic field, thus dwarfing most non-magnetic materials which exhibit this linearity. Its primary advantage over most other materials is that both linearity and the enormous magnitude are retained over a broad temperature range (0.3 K to 10 K), thus making it an attractive candidate for cryogenic sensor applications.

  15. Growth of GaN@InGaN Core-Shell and Au-GaN Hybrid Nanostructures for Energy Applications

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Kuykendall, Tevye; Aloni, Shaul; Jen-La Plante, Ilan; Mokari, Taleb

    2009-01-01

    We demonstrated a method to control the bandgap energy of GaN nanowires by forming GaN@InGaN core-shell hybrid structures using metal organic chemical vapor deposition (MOCVD). Furthermore, we show the growth of Au nanoparticles on the surface of GaN nanowires in solution at room temperature. The work shown here is a first step toward engineering properties that are crucial for the rational design and synthesis of a new class of photocatalytic materials. The hybrid structures were characterized by various techniques, including photoluminescence (PL), energy dispersive x-ray spectroscopy (EDS), transmission and scanning electron microscopy (TEM and SEM), and x-ray diffraction (XRD).

  16. DC Pro Software Tool Suite, Data Center Fact Sheet, Industrial Technologies Program

    SciTech Connect (OSTI)

    Not Available

    2009-04-01

    This fact sheet describes how DOE's Data Center Energy Profiler (DC Pro) Software Tool Suite and other resources can help U.S. companies identify ways to improve the efficiency of their data centers.

  17. DC-OPF Formulation with Price-Sensitive Demand Bids Junjie Sun and Leigh Tesfatsion

    E-Print Network [OSTI]

    Tesfatsion, Leigh

    DC-OPF Formulation with Price-Sensitive Demand Bids Junjie Sun and Leigh Tesfatsion Last Revised (TNCS) subject to various transmission constraints. As explained at length in Sun and Tesfation (2007

  18. ReHABit : claiming endangered structures in Washington DC to rethink subsidized housing

    E-Print Network [OSTI]

    Fowlkes, Catherine Kuhnle

    2007-01-01

    There is an affordable housing crisis today in Washington D.C. that is the result of a uniquely complicated history of a capital city and a current economic boom. This thesis responds to that crisis by proposing a new ...

  19. Dielectric relaxation and conduction in SrTiO{sub 3} thin films under dc bias

    SciTech Connect (OSTI)

    Ang, Chen; Yu, Zhi; Cross, L. E.; Guo, Ruyan; Bhalla, A. S.

    2001-08-06

    The dielectric and conduction behavior of SrTiO{sub 3} thin films deposited on a SrTiO{sub 3} single-crystal substrate is studied. Without dc bias, an obvious dielectric 'defect mode' in the dielectric loss is observed in the temperature range of {approx}100--200 K; however, no noticeable corresponding dielectric constant peak is observed. By applying a high dc bias ({>=}40 kV/cm), a dielectric constant peak with frequency dispersion appears in the same temperature range, the dielectric loss is increased, and simultaneously high dc conduction is observed. The induced dielectric constant peak is related to dc conduction and attributed to the coupling effect of the mobile carriers with the dielectric defect mode. {copyright} 2001 American Institute of Physics.

  20. DC power transmission from the Leningradskaya Nuclear Power Plant to Vyborg

    SciTech Connect (OSTI)

    Koshcheev, L. A.; Shul'ginov, N. G.

    2011-05-15

    DC power transmission from the Leningradskaya Nuclear Power Plant (LAES) to city of Vyborg is proposed. This will provide a comprehensive solution to several important problems in the development and control of the unified power system (EES) of Russia.

  1. New AC-DC Power Factor Correction Architecture Suitable for High Frequency Operation

    E-Print Network [OSTI]

    Lim, Seungbum

    This paper presents a novel ac-dc power factor correction (PFC) power conversion architecture for single-phase grid interface. The proposed architecture has significant advantages for achieving high efficiency, good power ...

  2. Vehicle Technologies Office Merit Review 2014: High Performance DC Bus Film Capacitor

    Office of Energy Efficiency and Renewable Energy (EERE)

    Presentation given by GE Global Research at 2014 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about high performance DC bus...

  3. Vehicle Technologies Office Merit Review 2015: High Performance DC Bus Film Capacitor

    Office of Energy Efficiency and Renewable Energy (EERE)

    Presentation given by GE Global Research at 2015 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about high performance DC bus...

  4. Multilevel-Dc-Bus Inverter For Providing Sinusoidal And Pwm Electrical Machine Voltages

    DOE Patents [OSTI]

    Su, Gui-Jia [Knoxville, TN

    2005-11-29

    A circuit for controlling an ac machine comprises a full bridge network of commutation switches which are connected to supply current for a corresponding voltage phase to the stator windings, a plurality of diodes, each in parallel connection to a respective one of the commutation switches, a plurality of dc source connections providing a multi-level dc bus for the full bridge network of commutation switches to produce sinusoidal voltages or PWM signals, and a controller connected for control of said dc source connections and said full bridge network of commutation switches to output substantially sinusoidal voltages to the stator windings. With the invention, the number of semiconductor switches is reduced to m+3 for a multi-level dc bus having m levels. A method of machine control is also disclosed.

  5. Development and evaluation of an implantable chronic DC stimulation and measurement probe for nerve regeneration studies 

    E-Print Network [OSTI]

    Macha, Douglas Bryan

    1995-01-01

    isotropic. The actual field strength or current density induced by the applied current is seldom directly measured in-vivo. This research seeks to evaluate the design of an implantable DC stimulator capable of delivering a constant, stable and measurable...

  6. DC Discharge Studies Using PIC-MCC: PIC Simulations Jeff Hammel & John Verboncoeur

    E-Print Network [OSTI]

    Wurtele, Jonathan

    DC Discharge Studies Using PIC-MCC: PIC Simulations Jeff Hammel & John Verboncoeur Electronics PIC Simulations (XPDP1) XPDP1, a 1D-3V PIC-MCC code (Verboncoeur et al., 1993), was used to simu- late

  7. Modeling of D/C motor driven synthetic jet acutators for flow separation control 

    E-Print Network [OSTI]

    Balasubramanian, Ashwin Kumar

    2004-11-15

    The objective of this research is to present a theoretical study of the compressibility effects on the performance of an electric D/C motor driven synthetic jet actuator for flow separation control. Hot wire anemometer experiments were conducted...

  8. Low speed control of a DC motor driving a mechanical system with fuzzy adaptive compensation 

    E-Print Network [OSTI]

    Hyun, Dongyoon

    1997-01-01

    A fuzzy adaptive feedforward control scheme in conjunction with classical feedback control is proposed for the low speed control of DC motors driving mechanical systems in the presence of friction. In the fuzzy adaptive scheme, a fuzzy logic based...

  9. Grid Modernization Highlighted in Washington DC in September with the Solar Decathlon

    Broader source: Energy.gov [DOE]

    Smart Grid is on display at the U.S. Department of Energy 2011 Solar Decathlon, held September 23 through October 2 on the National Mall, West Potomac Park, Washington, DC.  The decathlon...

  10. Area Efficient D/A Converters For Accurate DC Operation Brandon Royce Greenley

    E-Print Network [OSTI]

    Moon, Un-Ku

    . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 6.2 Mismatch Modeling For Area Optimization . . . . . . . . . . . . . . . . . . . . . . . 51 6Area Efficient D/A Converters For Accurate DC Operation by Brandon Royce Greenley A THESIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 5.1 Measurement Setup

  11. Assessment of Soil Erosion at a DC Park Facility Spring Valley Park

    E-Print Network [OSTI]

    District of Columbia, University of the

    park for the pilot assessment study. Failure to control erosion caused by the runoff of rain water can of Columbia Date: May 2005 Prepared for the DC Water Resources Research Institute Funded by USGS through

  12. Elastic properties of Pu metal and Pu-Ga alloys

    SciTech Connect (OSTI)

    Soderlind, P; Landa, A; Klepeis, J E; Suzuki, Y; Migliori, A

    2010-01-05

    We present elastic properties, theoretical and experimental, of Pu metal and Pu-Ga ({delta}) alloys together with ab initio equilibrium equation-of-state for these systems. For the theoretical treatment we employ density-functional theory in conjunction with spin-orbit coupling and orbital polarization for the metal and coherent-potential approximation for the alloys. Pu and Pu-Ga alloys are also investigated experimentally using resonant ultrasound spectroscopy. We show that orbital correlations become more important proceeding from {alpha} {yields} {beta} {yields} {gamma} plutonium, thus suggesting increasing f-electron correlation (localization). For the {delta}-Pu-Ga alloys we find a softening with larger Ga content, i.e., atomic volume, bulk modulus, and elastic constants, suggest a weakened chemical bonding with addition of Ga. Our measurements confirm qualitatively the theory but uncertainties remain when comparing the model with experiments.

  13. Transport properties of InGaAs/GaAs Heterostructures with {delta}-doped quantum wells

    SciTech Connect (OSTI)

    Baidus, N. V.; Vainberg, V. V.; Zvonkov, B. N.; Pylypchuk, A. S. Poroshin, V. N.; Sarbey, O. G.

    2012-05-15

    The lateral transport of electrons in single- and double-well pseudomorphic GaAs/n-InGaAs/GaAs heterostructures with quantum wells 50-100 meV deep and impurity {delta}-layers in the wells, with concentrations in the range 10{sup 11} < N{sub s} < 10{sup 12} cm{sup -2}, has been investigated. Single-well structures with a doped well at the center exhibit a nonmonotonic temperature dependence of the Hall coefficient and an increase in low-temperature electron mobility with an increase in the impurity concentration. The results obtained indicate that the impurity-band electron states play an important role in the conductivity of these structures. Involvement of the impurity band also allows to explain adequately the characteristics of the conductivity of double-well structures; in contrast to single-well structures, band bending caused by asymmetric doping is of great importance. The numerical calculations of conductivity within the model under consideration confirm these suggestions.

  14. Germanium subcells for multijunction GaInP/GaInAs/Ge solar cells

    SciTech Connect (OSTI)

    Kalyuzhnyy, N. A.; Gudovskikh, A. S.; Evstropov, V. V.; Lantratov, V. M.; Mintairov, S. A.; Timoshina, N. Kh.; Shvarts, M. Z.; Andreev, V. M.

    2010-11-15

    Photovoltaic converters based on n-GaInP/n-p-Ge heterostructures grown by the OMVPE under different conditions of formation of the p-n junction are studied. The heterostructures are intended for use as narrow-gap subcells of the GaInP/GaInAs/Ge three-junction solar cells. It is shown that, in Ge p-tn junctions, along with the diffusion mechanism, the tunneling mechanism of the current flow exists; therefore, the two-diode electrical equivalent circuit of the Ge p-n junction is used. The diode parameters are determined for both mechanisms from the analysis of both dark and 'light' current-voltage dependences. It is shown that the elimination of the component of the tunneling current allows one to increase the efficiency of the Ge subcell by {approx}1% with conversion of nonconcentrated solar radiation. The influence of the tunneling current on the efficiency of the Ge-based devices can be in practice reduced to zero at photogenerated current density of {approx}1.5 A/cm{sup 2} due to the use of the concentrated solar radiation.

  15. InGaN/GaN multiple-quantum-well light-emitting diodes with a grading InN composition suppressing the Auger recombination

    E-Print Network [OSTI]

    Demir, Hilmi Volkan

    ) In conventional InGaN/GaN light-emitting diodes (LEDs), thin InGaN quantum wells are usually adopted to mitigate recombination scales with the third power of the carrier density. As a result, the efficiency droop of the Auger recombination severely limits the LED performance. Here, we proposed and showed wide InGaN quantum wells

  16. Current crowding in GaInN / GaN LEDs grown on insulating substrates X. Guo, E. F. Schubert and J. Jahns

    E-Print Network [OSTI]

    Jahns, Jürgen

    Current crowding in GaInN / GaN LEDs grown on insulating substrates X. Guo, E. F. Schubert and J. Jahns Current crowding in mesa-structure GaInN/GaN light-emitting diodes (LEDs) grown on insulating and a saturation of the optical output power at high injection currents. It is shown that the optical power

  17. Investigation of the effect of temperature during off-state degradation of AlGaN/GaN High Electron Mobility Transistors

    E-Print Network [OSTI]

    Florida, University of

    , creating both electron traps and increasing electron tunneling through the defect states [4Investigation of the effect of temperature during off-state degradation of AlGaN/GaN High Electron 2011 a b s t r a c t AlGaN/GaN High Electron Mobility Transistors were found to exhibit a negative

  18. Determination of two-dimensional electron and hole gas carriers in AlGaN/GaN/AlN heterostructures grown by Metal

    E-Print Network [OSTI]

    Ozbay, Ekmel

    between GaN and a sapphire substrate, the dislocation scattering mechanism and the electron spillover

  19. Inductively coupled plasma–reactive ion etching of c- and a-plane AlGaN over the entire Al composition range: Effect of BCl{sub 3} pretreatment in Cl{sub 2}/Ar plasma chemistry

    SciTech Connect (OSTI)

    Shah, Amit P.; Laskar, Masihhur R.; Azizur Rahman, A.; Gokhale, Maheshwar R.; Bhattacharya, Arnab

    2013-11-15

    Inductively coupled plasma (ICP)–reactive ion etching (RIE) patterning is a standard processing step for UV and optical photonic devices based on III-nitride materials. There is little research on ICP-RIE of high Al-content AlGaN alloys and for nonpolar nitride orientations. The authors present a comprehensive study of the ICP-RIE of c- and a-plane AlGaN in Cl{sub 2}/Ar plasma over the entire Al composition range. The authors find that the etch rate decreases in general with increasing Al content, with different behavior for c- and a-plane AlGaN. They also study the effect of BCl{sub 3} deoxidizing plasma pretreatment. An ICP deoxidizing BCl{sub 3} plasma with the addition of argon is more efficient in removal of surface oxides from Al{sub x}Ga{sub 1?x}N than RIE alone. These experiments show that Al{sub x}Ga{sub 1?x}N etching is affected by the higher binding energy of AlN and the higher affinity of oxygen to aluminum compared to gallium, with oxides on a-plane AlGaN more difficult to etch as compared to oxides on c-plane AlGaN, specifically for high Al composition materials. The authors achieve reasonably high etch rate (?350 nm/min) for high Al-content materials with a smooth surface morphology at a low DC bias of ??45 VDC.

  20. Atomistic description of the electronic structure of InxGa1xAs alloys and InAsGaAs superlattices

    E-Print Network [OSTI]

    Kent, Paul

    quantum-wells15,20 (InxGa1 xAs)n /InP on InP and (InxGa1 xAs)n /GaAs on GaAs, and v GaAs-embedded InAs quantum dots.21­23 We wish to provide a uniform the- oretical description of the electronic structure-period dependence of the band offsets and interband transitions of InAs/GaAs systems on InP and GaAs substrates. DOI

  1. Gaseous and particulate emissions from a DC arc melter

    SciTech Connect (OSTI)

    Overcamp, T.J.; Speer, M.P.; Griner, S.J.; Cash, D.M. [Clemson Univ., Anderson, SC (United States)

    1997-12-31

    This paper presents the results of the gaseous and particulate emissions from eight experimental tests of a DC arc melter to treat simulated Savannah River soils contaminated with metals, surrogates for radionuclides, and organic debris. The gaseous analyses reported on the concentrations of oxygen, hydrogen, carbon monoxide, carbon dioxide, hydrogen, methane, nitric oxide, and nitrogen dioxide. The carbon dioxide concentration was high for all runs. For the runs with an air purge, the carbon monoxide concentration ranged up to 10% in the runs with the debris and 2% in the runs without debris. Hydrogen ranged up to 5% by with debris and up to 1% without debris. The methane concentration ranged up to 7,000 ppm{sub v} for the runs with debris and 2,000 ppm for the runs without debris. With a nitrogen purge, oxygen concentrations were less than 1%. The carbon dioxide concentrations ranged from 3 to 15%. Much of this carbon dioxide was probably due the carbonates added to the feed material. The carbon monoxide concentration ranged up to 20% with the debris and 7% without debris. Hydrogen was above 6% in with debris and up to 6% without debris. The methane concentration ranged up to 10,000 ppm{sub v} with debris and 4,000 ppm{sub v} without debris. The particulate concentrations exiting ranged from 32 to 145 g/m{sup 3}. From the chemical analyses, the primary elements were silicon and calcium. The CHN analyses indicated that carbon, probably as carbonates, are an additional component in the particulate matter. The estimated emissions were at a level of 3% or less for cerium, up to 7% for nickel, and 11 to 30% for cesium.

  2. Improved hole distribution in InGaN/GaN light-emitting diodes with graded thickness quantum barriers

    E-Print Network [OSTI]

    Demir, Hilmi Volkan

    is 48.3%. Moreover, the light output power was enhanced from 770 mW for the ETQB LEDs to 870 m; accepted 3 June 2013; published online 19 June 2013) InGaN/GaN light-emitting diodes (LEDs) with graded , which is much smaller than that of the conventional equal-thickness quantum barriers (ETQB) LED, which

  3. Low-frequency noise in GaNAlGaN heterostructure field-effect transistors at cryogenic temperatures

    E-Print Network [OSTI]

    Pala, Nezih

    that the 1/f noise in GaN/AlGaN HFETs might be caused by electron tunneling from the channel to the traps was practically independent of the frequency of analysis. The model linking this maximum to the electron tunneling Department of Electrical, Computer, and Systems Engineering and Center for Integrated Electronics

  4. Development of GaAs/Si and GaAs/Si monolithic structures for future space solar cells

    SciTech Connect (OSTI)

    Spitzer, M.B.; Vernon, S.M.; Wolfson, R.G.; Tobin, S.P.

    1984-01-01

    The results of heteroepitaxial growth of GaAs and GaAlAs directly on Si are presented, and applications to new cell structures are suggested. The novel feature is the elimination of a Ge lattice transition region. This feature not only reduces the cost of substrate preparation, but also makes possible the fabrication of high efficiency monolithic cascade structures. All films to be discussed were grown by organometallic chemical vapor deposition at atmospheric pressure. This process yielded reproducible, large-area films of GaAs, grown directly on Si, that are tightly adherent and smooth, and are characterized by a defect density of 5 x 10(6) power/sq cm. Preliminary studies indicate that GaAlAs can also be grown in this way. A number of promising applications are suggested. Certainly these substrates are ideal for low-weight GaAs space solar ells. For very high efficiency, the absence of Ge makes the technology attractive for GaAlAs/Si monolithic cascades, in which the Si substrates would first be provided with a suitable p/n junction. An evaluation of a three bandgap cascade consisting of appropriately designed GaAlAs/GaAs/Si layers is also presented.

  5. Wavelength-resolved low-frequency noise of GaInN/GaN green light emitting diodes

    E-Print Network [OSTI]

    Wetzel, Christian M.

    Wavelength-resolved low-frequency noise of GaInN/GaN green light emitting diodes S. L. Rumyantseva well light emitting diodes. The light intensity noise was measured as a function of wavelength within the light emitting diode spectral emission line. The spectral noise density is found to increase

  6. GaAs-based self-aligned laser incorporating InGaP opto-electronic confinement layer

    E-Print Network [OSTI]

    be well suited for exploitation of long wavelength quantum dot and dilute nitride technology, resulting in single lateral mode emission from an In0.17Ga0.83As double quantum well laser. Introduction: Lasers based on the GaAs materials system offer advan- tages over their InP counterparts, such as the use

  7. Improved performance of In,,Ga...As/GaAs quantum dot solar cells via light scattering by nanoparticles

    E-Print Network [OSTI]

    Yu, Edward T.

    of QDs in the context of our work is attractive for achieving long wavelength absorption in solar cells enhancement at all infrared wave- lengths in the device photocurrent spectrum. Epitaxial layer structuresImproved performance of In,,Ga...As/GaAs quantum dot solar cells via light scattering

  8. Output Harmonic Termination Techniques for AlGaN/GaN HEMT Power Amplifiers Using Active Integrated Antenna Approach

    E-Print Network [OSTI]

    Itoh, Tatsuo

    Output Harmonic Termination Techniques for AlGaN/GaN HEMT Power Amplifiers Using Active Integrated 1200, Los Angeles, CA 90045 Abstract -- In this paper, effects of output harmonic terminations on PAE termination, we observe a substantial increase in PAE and output power. Further, we demonstrate the high

  9. SnO2 functionalized AlGaN/GaN high electron mobility transistor for hydrogen sensing applications

    E-Print Network [OSTI]

    Florida, University of

    for spacecraft and other long-term sensing applications. However, hydrogen is a dangerous gas for storage for monitoring leakage of hydrogen storage equipment and fuel tanks for spacecraft and hydrogen fuel cellSnO2 functionalized AlGaN/GaN high electron mobility transistor for hydrogen sensing applications

  10. Mn-doped Ga(As,P) and (Al,Ga)As ferromagnetic semiconductors: Electronic structure calculations 

    E-Print Network [OSTI]

    Masek, J.; Kudrnovsky, J.; Maca, F.; Sinova, Jairo; MacDonald, A. H.; Campion, R. P.; Gallagher, B. L.; Jungwirth, T.

    2007-01-01

    A remarkable progress towards functional ferromagnetic semiconductor materials for spintronics has been achieved in p-type (Ga,Mn)As. Robust hole-mediated ferromagnetism has, however, been observed also in other III-V hosts such as antimonides, Ga...

  11. DESIGN, GROWTH, FABRICATION AND CHARACTERIZATION OF HIGH-BAND GAP InGaN/GaN SOLAR CELLS

    E-Print Network [OSTI]

    Honsberg, Christiana

    photovoltaic efficiency of 39% at 236 suns is achieved by a triple-junction GaInP- GaInAs-Ge tandem solar cell [1]. While the achievable efficiency of triple-junction tandem solar cells is restricted to about 40% [2], modeling results show that a tandem solar cell of five junctions or greater, or an equivalent

  12. Progress toward technology transition of GaInP{sub 2}/GaAs/Ge multijunction solar cells

    SciTech Connect (OSTI)

    Keener, D.N.; Marvin, D.C.; Brinker, D.J.; Curtis, H.B.; Price, P.M.

    1997-12-31

    The objective of the joint WL/PL/NASA Multijunction Solar Cell Manufacturing Technology (ManTech) Program is to scale up high efficiency GaInP{sub 2}/GaAs/Ge multijunction solar cells to production size, quantity, and yield while limiting the production cost/Watt ($/W) to 15% over GaAs cells. Progress made by the program contractors, Spectrolab and TECSTAR, include, respectively, best cell efficiencies of 25.76% and 24.7% and establishment of 24.2% and 23.8% lot average efficiency baseline designs. The paper also presents side-by-side testing results collected by Phillips Laboratory and NASA Lewis on Phase 1 deliverable cells, which shows compliance with program objectives. Cell performance, pre- and post-radiation, and temperature coefficient results on initial production GaInP{sub 2}/GaAs/Ge solar cells will be presented.

  13. Fact #755: November 26, 2012 Chargepoint, Blink and Nissan Take...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    0 28 54 DC 22 4 0 4 0 4 34 DE 2 0 3 0 0 2 7 FL 236 1 56 1 0 26 320 GA 3 5 33 33 0 24 98 HI 6 1 4 0 64 4 79 IA 13 0 5 0 4 3 25 ID 0 0 3 0 0 4 7 IL 116 4 38 1 0 23 182 IN 18 1 13 1...

  14. Abstract--A novel control scheme for improving the power efficiency of low-voltage DC-DC converters for battery-powered,

    E-Print Network [OSTI]

    Rincon-Mora, Gabriel A.

    -DC converters for battery-powered, portable applications is presented. In such applications, light- load efficiency is crucial for extending battery life, since mobile devices operate in stand-by mode for most-of-the-art techniques. As a result, the battery life in a typical DSP microprocessor application is improved by 7

  15. Optimizing Energy Savings from Direct-DC in U.S. Residential Buildings

    SciTech Connect (OSTI)

    Garbesi, Karina; Vossos, Vagelis; Sanstad, Alan; Burch, Gabriel

    2011-10-13

    An increasing number of energy efficient appliances operate on direct current (DC) internally, offering the potential to use DC from renewable energy systems directly and avoiding the losses inherent in converting power to alternating current (AC) and back. This paper investigates that potential for net-metered residences with on-site photovoltaics (PV) by modeling the net power draw of the ‘direct-DC house’ with respect to today’s typical configuration, assuming identical DC-internal loads. Power draws were modeled for houses in 14 U.S. cities, using hourly, simulated PV-system output and residential loads. The latter were adjusted to reflect a 33% load reduction, representative of the most efficient DC-internal technology, based on an analysis of 32 electricity end-uses. The model tested the effect of climate, electric vehicle (EV) loads, electricity storage, and load shifting on electricity savings; a sensitivity analysis was conducted to determine how future changes in the efficiencies of power system components might affect savings potential. Based on this work, we estimate that net-metered PV residences could save 5% of their total electricity load for houses without storage and 14% for houses with storage. Based on residential PV penetration projections for year 2035 obtained from the National Energy Modeling System (2.7% for the reference case and 11.2% for the extended policy case), direct-DC could save the nation 10 trillion Btu (without storage) or 40 trillion Btu (with storage). Shifting the cooling load by two hours earlier in the day (pre-cooling) has negligible benefits for energy savings. Direct-DC provides no energy savings benefits for EV charging, to the extent that charging occurs at night. However, if charging occurred during the day, for example with employees charging while at work, the benefits would be large. Direct-DC energy savings are sensitive to power system and appliance conversion efficiencies but are not significantly influenced by climate. While direct-DC for residential applications will most likely arise as a spin-off of developments in the commercial sector—because of lower barriers to market entry and larger energy benefits resulting from the higher coincidence between load and insolation—this paper demonstrates that there are substantial benefits in the residential sector as well. Among residential applications, space cooling derives the largest energy savings from being delivered by a direct-DC system. It is the largest load for the average residence on a national basis and is particularly so in high-load regions. It is also the load with highest solar coincidence.

  16. Ferromagnetism in undoped One-dimensional GaN Nanowires

    SciTech Connect (OSTI)

    Jeganathan, K. E-mail: jagan@physics.bdu.ac.in; Purushothaman, V.; Debnath, R.; Arumugam, S.

    2014-05-15

    We report an intrinsic ferromagnetism in vertical aligned GaN nanowires (NW) fabricated by molecular beam epitaxy without any external catalyst. The magnetization saturates at ?0.75 × emu/gm with the applied field of 3000 Oe for the NWs grown under the low-Gallium flux of 2.4 × 10{sup ?8} mbar. Despite a drop in saturation magnetization, narrow hysteresis loop remains intact regardless of Gallium flux. Magnetization in vertical standing GaN NWs is consistent with the spectral analysis of low-temperature photoluminescence pertaining to Ga-vacancies associated structural defects at the nanoscale.

  17. Characterization of Zns-GaP Naon-composites

    SciTech Connect (OSTI)

    Todd, V.

    1993-12-09

    It proved possible to produce consistent, high-quality nanocrystalline ZnS powders with grain sizes as small as 8 nm. These powders are nano-porous and are readily impregnated with GaP precursor, although inconsistently. Both crystal structure and small grain size of the ZnS can be maintained through the use of GaP. Heat treatment of the impregnated powders results in a ZnS-GaP composite structure where the grain sizes of the phases are on the order of 10--20 nm. Conventional powder processing should be able to produce optically dense ceramic compacts with improved mechanical properties and suitable IR transmission.

  18. Indium distribution at the interfaces of (Ga,In)(N,As)/GaAs quantum wells

    SciTech Connect (OSTI)

    Luna, E.; Ishikawa, F.; Batista, P. D.; Trampert, A. [Paul-Drude-Institut fuer Festkoerperelektronik, Hausvogteiplatz 5-7, D-10117, Berlin (Germany)

    2008-04-07

    The indium distribution across (Ga,In)(N,As) quantum wells is determined by using transmission electron microscopy techniques. Inside the quantum well, the indium distribution is well described by Muraki's segregation model; however, it fails in reflecting the concentration at the interfaces. To describe them, we propose a sigmoidal law which defines the smooth variation of the indium concentration with the position and provides a systematic and quantitative characterization of the interfaces. The thermal stability of the interfaces and their interplay with segregation effects are discussed. A connection between the high thermal robustness of the interfaces and the inherent thermodynamic miscibility gap of the alloy is suggested.

  19. Local Structures and Interface Morphology of InGaAsN Thin Films Grown on GaAs

    SciTech Connect (OSTI)

    Allerman, A.A.; Chen, J.G.; Geisz, J.F.; Huang, S.; Hulbert, S.L.; Jones, E.D.; Kao, Y.H.; Kurtz, S.; Kurtz, S.R.; Olson, J.M.; Soo, Y.L.

    1999-02-23

    The compound semiconductor system InGaAsN exhibits many intriguing properties which are particularly useful for the development of innovative high efficiency thin film solar cells and long wavelength lasers. The bandgap in these semiconductors can be varied by controlling the content of N and In and the thin films can yet be lattice-matched to GaAs. In the present work, x-ray absorption fine structure (XAFS) and grazing incidence x-ray scattering (GIXS) techniques have been employed to probe the local environment surrounding both N and In atoms as well as the interface morphology of InGaAsN thin films epitaxially grown on GaAs. The soft x-ray XAFS results around nitrogen K-edge reveal that N is in the sp{sup 3} hybridized bonding configuration in InGaAsN and GaAsN, suggesting that N impurities most likely substitute for As sites in these two compounds. The results of In K-edge XAFS suggest a possible trend of a slightly larger coordination number of As nearest neighbors around In atoms in InGaAsN samples with a narrower bandgap whereas the In-As interatomic distance remains practically the same as in InAs within the experimental uncertainties. These results combined suggest that N-substitution of the As sites plays an important role of bandgap-narrowing while in the meantime counteracting the compressive strain caused by In-doping. Grazing incidence x-ray scattering (GIXS) experiments verify that InGaAsN thin films can indeed form very smooth interfaces with GaAs yielding an average interfacial roughness of 5-20{angstrom}.

  20. Structural and optical properties of GaAs-based heterostructures with Ge and Ge/InGaAs quantum wells

    SciTech Connect (OSTI)

    Aleshkin, V. Ya.; Dubinov, A. A., E-mail: sanya@ipm.sci-nnov.ru; Drozdov, M. N. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Zvonkov, B. N. [Nizhni Novgorod State University, Research Physical Technical Institute (Russian Federation); Kudryavtsev, K. E.; Tonkikh, A. A.; Yablonskiy, A. N. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Werner, P. [Max Planck Institute of Microstructure Physics (Germany)

    2013-05-15

    GaAs-based heterostructures with Ge and Ge/InGaAs quantum wells are grown by laser-assisted sputtering. Structural and optical studies of the heterostructures are carried out. A broad photoluminescence line is observed in the wavelength range from 1300 to 1650 nm. The line corresponds to indirect transitions in the momentum space of the Ge quantum wells and to transitions between the In{sub 0.28}Ga{sub 0.72}As and Ge layers, indirect in coordinate space, but direct in momentum space.

  1. Electrical spin injection using GaCrN in a GaN based spin light emitting diode

    SciTech Connect (OSTI)

    Banerjee, D.; Ganguly, S.; Saha, D.; Adari, R.; Sankaranarayan, S.; Kumar, A.; Aldhaheri, R. W.; Hussain, M. A.; Balamesh, A. S.

    2013-12-09

    We have demonstrated electrical spin-injection from GaCrN dilute magnetic semiconductor (DMS) in a GaN-based spin light emitting diode (spin-LED). The remanent in-plane magnetization of the thin-film semiconducting ferromagnet has been used for introducing the spin polarized electrons into the non-magnetic InGaN quantum well. The output circular polarization obtained from the spin-LED closely follows the normalized in-plane magnetization curve of the DMS. A saturation circular polarization of ?2.5% is obtained at 200?K.

  2. Effects of light illumination on electron velocity of AlGaN/GaN heterostructures under high electric field

    SciTech Connect (OSTI)

    Guo, Lei; Yang, Xuelin Cheng, Jianpeng; Sang, Ling; Xu, Fujun; Tang, Ning; Feng, Zhihong; Lv, Yuanjie; Wang, Xinqiang; Shen, B.; Ge, Weikun

    2014-12-15

    We have investigated the variation of electron velocity in AlGaN/GaN heterostructures depending on illuminating light intensity and wavelength. It is shown that the electron velocity at high electric field increases under above-band light illumination. This electron velocity enhancement is found to be related to the photo-generated cold holes which interact with hot electrons and thus accelerate the energy relaxation at high electric field. The results suggest an alternative way to improve the electron energy relaxation rate and hence the electron velocity in GaN based heterostructures.

  3. High-power InGaAs/GaAs quantum-well laser with enhanced broad spectrum of stimulated emission

    SciTech Connect (OSTI)

    Wang, Huolei; Yu, Hongyan; Zhou, Xuliang; Kan, Qiang; Yuan, Lijun; Wang, Wei; Pan, Jiaoqing, E-mail: jqpan@semi.ac.cn [Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Science, Beijing 100083 (China); Chen, Weixi [State Key Lab for Mesoscopic Physics and School of Physics, Peking University, Beijing 100871 (China); Ding, Ying, E-mail: Ying.Ding@glasgow.ac.uk [School of Engineering, University of Glasgow, Glasgow G12 8LT (United Kingdom)

    2014-10-06

    We report the demonstration of an InGaAs/GaAs quantum well (QW) broadband stimulated emission laser with a structure that integrated a GaAs tunnel junction with two QW active regions. The laser exhibits ultrabroad lasing spectral coverage of ?51?nm at a center wavelength of 1060?nm with a total emission power of 790 mW, corresponding to a high average spectral power density of 15.5 mW/nm, under pulsed current conditions. Compared to traditional lasers, this laser with an asymmetric separate-confinement heterostructure shows broader lasing bandwidth and higher spectral power density.

  4. One-dimensional hybrid simulation of the dc/RF combined driven capacitively coupled CF{sub 4} plasmas

    SciTech Connect (OSTI)

    Wang Shuai [School of Science, Northeastern University, Shenyang 110891 (China); Xu Xiang; Wang Younian [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

    2012-11-15

    We developed a one-dimensional hybrid model to simulate the dc/RF combined driven capacitively coupled plasma for CF{sub 4} discharges. The numerical results show the influence of the dc source on the plasma density distribution, ion energy distributions (IEDs), and ion angle distributions (IADs) on both RF and dc electrodes. The increase of dc voltage impels more ions with high energy to the electrode applied to the dc source, which makes the IEDs at the dc electrode shift toward higher energy and the peaks in IADs shift toward the small angle region. At the same time, it also decreases ion-energy at the RF electrode and enlarges the ion-angles which strike the RF electrode.

  5. Linear and nonlinear optical properties of GaAs/Al{sub x}Ga{sub 1?x}As/GaAs/Al{sub y}Ga{sub 1?y}As multi-shell spherical quantum dot

    SciTech Connect (OSTI)

    Emre Kavruk, Ahmet E-mail: aekavruk@gmail.com; Koc, Fatih; Sahin, Mehmet E-mail: mehsahin@gmail.com

    2013-11-14

    In this work, the optical properties of GaAs/Al{sub x}Ga{sub 1?x}As/GaAs/Al{sub y}Ga{sub 1?y}As multi-shell quantum dot heterostructure have been studied as a function of Al doping concentrations for cases with and without a hydrogenic donor atom. It has been observed that the absorption coefficient strength and/or resonant absorption wavelength can be adjusted by changing the Al content of inner-barrier and/or outer-barrier regions. Besides, it has been shown that the donor atom has an important effect on the control of the electronic and optical properties of the structure. The results have been presented as a function of the Al contents of the inner-barrier x and outer-barrier y regions and probable physical reasons have been discussed.

  6. Electrical degradation mechanisms of RF power GaAs PHEMTs

    E-Print Network [OSTI]

    Villanueva, Anita A. (Anita Ariel), 1978-

    2007-01-01

    GaAs Pseudomorphic High-Electron Mobility Transistors (PHEMTs) are widely used in RF power applications. Since these devices typically operate at high power levels and under high voltage biasing, their electrical reliability ...

  7. Evaporation-based Ge/.sup.68 Ga Separation

    DOE Patents [OSTI]

    Mirzadeh, Saed (Albuquerque, NM); Whipple, Richard E. (Los Alamos, NM); Grant, Patrick M. (Los Alamos, NM); O'Brien, Jr., Harold A. (Los Alamos, NM)

    1981-01-01

    Micro concentrations of .sup.68 Ga in secular equilibrium with .sup.68 Ge in strong aqueous HCl solution may readily be separated in ionic form from the .sup.68 Ge for biomedical use by evaporating the solution to dryness and then leaching the .sup.68 Ga from the container walls with dilute aqueous solutions of HCl or NaCl. The chloro-germanide produced during the evaporation may be quantitatively recovered to be used again as a source of .sup.68 Ga. If the solution is distilled to remove any oxidizing agents which may be present as impurities, the separation factor may easily exceed 10.sup.5. The separation is easily completed and the .sup.68 Ga made available in ionic form in 30 minutes or less.

  8. Panel: Microgrid Research and Field Testing IEEE PES General Meeting, 24-28 June 2007, Tampa, FL 1 In general, a microgrid can operate in both the grid-connected

    E-Print Network [OSTI]

    Panel: Microgrid Research and Field Testing IEEE PES General Meeting, 24-28 June 2007, Tampa, FL 1 Abstract In general, a microgrid can operate in both the grid-connected mode and the islanded mode where the microgrid is interfaced to the main power system by a fast semiconductor switch called static switch, (SS

  9. A. Kusiak, Data Mining and Decision Making, in B.V. Dasarathy (Ed.), Proceedings of the SPIE Conference on Data Mining and Knowledge Discovery: Theory, Tools, and Technology IV, Vol. 4730, SPIE, Orlando, FL, April 2002, pp. 155-165.

    E-Print Network [OSTI]

    Kusiak, Andrew

    A. Kusiak, Data Mining and Decision Making, in B.V. Dasarathy (Ed.), Proceedings of the SPIE Conference on Data Mining and Knowledge Discovery: Theory, Tools, and Technology IV, Vol. 4730, SPIE, Orlando, FL, April 2002, pp. 155-165. Data Mining and Decision Making Andrew Kusiak Department of Mechanical

  10. Low temperature carrier redistribution dynamics in InGaN/GaN quantum wells

    SciTech Connect (OSTI)

    Badcock, T. J., E-mail: Thomas.badcock@crl.toshiba.co.uk; Dawson, P.; Davies, M. J. [School of Physics and Astronomy, Photon Science Institute, Alan Turing Building, University of Manchester, Manchester M13 9PL (United Kingdom); Kappers, M. J.; Massabuau, F. C.-P.; Oehler, F.; Oliver, R. A.; Humphreys, C. J. [Department of Materials Science and Metallurgy, 27 Charles Babbage Road, University of Cambridge, Cambridge CB3 0FS (United Kingdom)

    2014-03-21

    We have studied the carrier recombination dynamics in an InGaN/GaN multiple quantum well structure as a function of emission energy and excitation density between temperatures of 10?K and 100?K. Under relatively low levels of excitation, the photoluminescence (PL) intensity and decay time of emission on the high energy side of the luminescence spectrum decrease strongly between 10?K and 50?K. In contrast, for emission detected on the low energy side of the spectrum, the PL intensity and decay time increase over the same temperature range. These results are consistent with a thermally activated carrier redistribution process in which the (temperature dependent) average timescale for carrier transfer into or out of a localised state depends on the energy of the given state. Thus, the transfer time out of shallow, weakly localised states is considerably shorter than the arrival time into more deeply localised states. This picture is consistent with carriers hopping between localisation sites in an uncorrelated disorder potential where the density of localised states decreases with increasing localisation depth, e.g., a exponential or Gaussian distribution resulting from random alloy disorder. Under significantly higher levels of excitation, the increased occupation fraction of the localised states results in a greater average separation distance between unoccupied localised states, causing a suppression of the spectral and dynamic signatures of the hopping transfer of carriers.

  11. Green (In,Ga,Al)P-GaP light-emitting diodes grown on high-index GaAs surfaces

    SciTech Connect (OSTI)

    Ledentsov, N. N., E-mail: nikolay.ledentsov@v-i-systems.com; Shchukin, V. A. [VI Systems GmbH, Hardenbergstr. 7, Berlin D-10623 (Germany); Lyytikäinen, J.; Okhotnikov, O. [Optoelectronics Research Centre, Tampere University of Technology, Tampere FI-33720 (Finland); Shernyakov, Yu. M.; Payusov, A. S.; Gordeev, N. Yu.; Maximov, M. V. [A. F. Ioffe Physical Technical Institute of the Russian Academy of Sciences, Politekhnicheskaya 26, St. Petersburg 194021 (Russian Federation); Schlichting, S.; Nippert, F.; Hoffmann, A. [Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstrasse 36, Berlin D-10623 (Germany)

    2014-11-03

    We report on green (550–560?nm) electroluminescence (EL) from (Al{sub 0.5}Ga{sub 0.5}){sub 0.5}In{sub 0.5}P-(Al{sub 0.8}Ga{sub 0.2}){sub 0.5}In{sub 0.5}P double p-i-n heterostructures with monolayer-scale GaP insertions in the cladding layers and light-emitting diodes based thereupon. The structures are grown side-by-side on high-index and (100) GaAs substrates by molecular beam epitaxy. At moderate current densities (?500?A/cm{sup 2}), the EL intensity of the structures is comparable for all substrate orientations. Opposite to the (100)-grown strictures, the EL spectra of (211) and (311)-grown devices are shifted towards shorter wavelengths (?550?nm at room temperature). At high current densities (>1?kA/cm{sup 2}), a much higher EL intensity is achieved for the devices grown on high-index substrates. The integrated intensity of (311)-grown structures gradually saturates at current densities above 4?kA/cm{sup 2}, whereas no saturation is revealed for (211)-grown structures up to the current densities above 14?kA/cm{sup 2}. We attribute the effect to the surface orientation-dependent engineering of the GaP band structure, which prevents the escape of the nonequilibrium electrons into the indirect conduction band minima of the p-doped (Al{sub 0.8}Ga{sub 0.2}){sub 0.5}In{sub 0.5}P cladding layers.

  12. Influence of stress on optical transitions in GaN nanorods containing a single InGaN/GaN quantum disk

    SciTech Connect (OSTI)

    Zhuang, Y. D.; Shields, P. A.; Allsopp, D. W. E., E-mail: d.allsopp@bath.ac.uk [Department of Electronic and Electrical Engineering, University of Bath, Bath BA2 7AY (United Kingdom); Bruckbauer, J.; Edwards, P. R.; Martin, R. W. [Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG (United Kingdom)

    2014-11-07

    Cathodoluminescence (CL) hyperspectral imaging has been performed on GaN nanorods containing a single InGaN quantum disk (SQD) with controlled variations in excitation conditions. Two different nanorod diameters (200 and 280?nm) have been considered. Systematic changes in the CL spectra from the SQD were observed as the accelerating voltage of the electron beam and its position of incidence are varied. It is shown that the dominant optical transition in the SQD varies across the nanorod as a result of interplay between the contributions of the deformation potential and the quantum-confined Stark effect to the transition energy as consequence of radial variation in the pseudomorphic strain.

  13. High intensity low temperature (HILT) performance of space concentrator GaInP/GaInAs/Ge MJ SCs

    SciTech Connect (OSTI)

    Shvarts, Maxim Z., E-mail: shvarts@scell.ioffe.ru; Kalyuzhnyy, Nikolay A.; Mintairov, Sergey A.; Soluyanov, Andrei A.; Timoshina, Nailya Kh. [Ioffe Physical-Technical Institute, 26 Polytekhnicheskaya str., St.-Petersburg, 194021 (Russian Federation); Gudovskikh, Alexander S. [Saint-Petersburg Academic University - Nanotechnology Research and Education Centre RAS, St. Petersburg, 194021 (Russian Federation); Luque, Antonio [Ioffe Physical-Technical Institute, 26 Polytekhnicheskaya str., St.-Petersburg, 194021, Russia and Instituto de Energia Solar, Universidad Politecnica de Madrid, Madrid (Spain)

    2014-09-26

    In the work, the results of an investigation of GaInP/GaInAs/Ge MJ SCs intended for converting concentrated solar radiation, when operating at low temperatures (down to ?190 °C) are presented. A kink of the cell I-V characteristic has been observed in the region close to V{sub oc} starting from ?20°C at operation under concentrated sunlight. The causes for its occurrence have been analyzed and the reasons for formation of a built-in potential barrier for majority charge carriers at the n-GaInP/n-Ge isotype hetero-interface are discussed. The effect of charge carrier transport in n-GaInP/n-pGe heterostructures on MJ SC output characteristics at low temperatures has been studied including EL technique.

  14. The origin and reduction of switching noise in GaAs/AlGaAs lateral gated devices

    E-Print Network [OSTI]

    Davies, John H.

    to cryogenic temperature with all gates grounded to the substrate to protect against electrostatic effects in AlGaAs: electrons `freeze' into deep traps ­ DX centres ­ below about 150 K. The occupation of donors

  15. Design and fabrication of InGaN/GaN heterojunction bipolar transistors for microwave power amplifiers

    E-Print Network [OSTI]

    Keogh, David Martin

    2006-01-01

    assuming the material growth technology allows for all ofand a relatively immature growth technology, as well as theof the art for InGaN growth technology. Epitaxial growth of

  16. Polarization field engineering of GaN/AlN/AlGaN superlattices for enhanced thermoelectric properties

    SciTech Connect (OSTI)

    Sztein, Alexander, E-mail: asztein@umail.ucsb.edu [Materials Department, University of California, Santa Barbara, California 93106 (United States); Bowers, John E.; DenBaars, Steven P.; Nakamura, Shuji [Materials Department, University of California, Santa Barbara, California 93106 (United States); Electrical and Computer Engineering Department, University of California, Santa Barbara, California 93106 (United States)

    2014-01-27

    A novel polarization field engineering based strategy to simultaneously achieve high electrical conductivity and low thermal conductivity in thermoelectric materials is demonstrated. Polarization based electric fields are used to confine electrons into two-dimensional electron gases in GaN/AlN/Al{sub 0.2}Ga{sub 0.8}N superlattices, resulting in improved electron mobilities as high as 1176 cm{sup 2}/Vs and in-plane thermal conductivity as low as 8.9?W/mK. The resulting room temperature ZT values reach 0.08, a factor of four higher than InGaN and twelve higher than GaN, demonstrating the potential benefits of this polarization based engineering strategy for improving the ZT and efficiencies of thermoelectric materials.

  17. Si-CMOS-Like Integration of AlGaN/GaN Dielectric-Gated High-Electron-Mobility Transistors 

    E-Print Network [OSTI]

    Johnson, Derek Wade

    2014-07-31

    production is projected to consume ~100,000 wafers per year by 2015 (Yole Development, “Power GaN – 2012 Edition”), this manufacturing breakthrough represents potential savings of ~$17 million per year....

  18. Characterization of the gate oxide of an AlGaN/GaN high electron mobility transistor

    E-Print Network [OSTI]

    Florida, University of

    2011; published online 21 March 2011 A subnanometer thick interfacial oxide layer present between used to characterize a Ni/AlGaN interfacial oxide layer with subnanometer thickness. The semiconducting

  19. The first principle study of Ni{sub 2}ScGa and Ni{sub 2}TiGa

    SciTech Connect (OSTI)

    Özduran, Mustafa; Turgut, Kemal; Arikan, Nihat; ?yigör, Ahmet; Candan, Abdullah

    2014-10-06

    We computed the electronic structure, elastic moduli, vibrational properties, and Ni{sub 2}TiGa and Ni{sub 2}ScGa alloys in the cubic L2{sub 1} structure. The obtained equilibrium lattice constants of these alloys are in good agreement with available data. In cubic systems, there are three independent elastic constants, namely C{sub 11}, C{sub 12} and C{sub 44}. We calculated elastic constants in L2{sub 1} structure for Ni{sub 2}TiGa and Ni{sub 2}ScGa using the energy-strain method. The electronic band structure, total and partial density of states for these alloys were investigated within density functional theory using the plane-wave pseudopotential method implemented in Quantum-Espresso program package. From band structure, total and projected density of states, we observed metallic characters of these compounds. The electronic calculation indicate that the predominant contributions of the density of states at Fermi level come from the Ni 3d states and Sc 3d states for Ni{sub 2}TiGa, Ni 3d states and Sc 3d states for Ni{sub 2}ScGa. The computed density of states at Fermi energy are 2.22 states/eV Cell for Ni{sub 2}TiGa, 0.76 states/eV Cell for Ni{sub 2}ScGa. The vibrational properties were obtained using a linear response in the framework at the density functional perturbation theory. For the alloys, the results show that the L2{sub 1} phase is unstable since the phonon calculations have imagine modes.

  20. Optical investigation of InAs quantum dots inserted in AlGaAs/GaAs modulation doped heterostructure

    SciTech Connect (OSTI)

    Khmissi, H.; Baira, M.; Bouzaieene, L.; Saidi, F.; Maaref, H. [Laboratoire de Micro-optoelectronique et Nanostructures, Universite de Monastir (Tunisia); Sfaxi, L. [Laboratoire de Micro-optoelectronique et Nanostructures, Universite de Monastir (Tunisia); Universite de Sousse Faculte des Sciences de Monastir, Avenue de l'Environnement 5019 Monastir (Tunisia); Bru-Chevallier, C. [Institut des Nanotechnologies de Lyon (INL), CNRS UMR-5270, INSA-LYON, 7, Avenue Jean Capelle, Bat. Blaise Pascal, 69621 Villeurbanne (France)

    2011-03-01

    Optical properties of InAs quantum dots (QDs) inserted in AlGaAs/GaAs modulation doped heterostructure are investigated. To study the effect of carrier transfer behavior on the luminescence of self-assembled quantum dots, a series of sample has been prepared using molecular beam epitaxy (Riber 32 system) in which we have varied the thickness separating the delta dopage and the InAs quantum dots layer. Photoluminescence spectra show the existence of two peaks that can be attributed to transition energies from the ground state (E{sub 1}-HH{sub 1}) and the first excited state (E{sub 2}-HH{sub 2}). Two antagonist effects have been observed, a blue shift of the emission energies result from electron transferred from the AlGaAs/GaAs heterojunction to the InAs quantum dots and a red shift caused by the quantum confined Stark effect due to the internal electric field existing In the AlGaAs/GaAs heterojunction.

  1. Effects of high-temperature AIN buffer on the microstructure of AlGaN/GaN HEMTs

    SciTech Connect (OSTI)

    Coerekci, S.; Oeztuerk, M. K.; Yu, Hongbo; Cakmak, M.; Oezcelik, S.; Oezbay, E.

    2013-06-15

    Effects on AlGaN/GaN high-electron-mobility transistor structure of a high-temperature AlN buffer on sapphire substrate have been studied by high-resolution x-ray diffraction and atomic force microscopy techniques. The buffer improves the microstructural quality of GaN epilayer and reduces approximately one order of magnitude the edge-type threading dislocation density. As expected, the buffer also leads an atomically flat surface with a low root-mean-square of 0.25 nm and a step termination density in the range of 10{sup 8} cm{sup -2}. Due to the high-temperature buffer layer, no change on the strain character of the GaN and AlGaN epitaxial layers has been observed. Both epilayers exhibit compressive strain in parallel to the growth direction and tensile strain in perpendicular to the growth direction. However, an high-temperature AlN buffer layer on sapphire substrate in the HEMT structure reduces the tensile stress in the AlGaN layer.

  2. p-doping-free InGaN/GaN light-emitting diode driven by three-dimensional hole gas

    SciTech Connect (OSTI)

    Zhang, Zi-Hui; Tiam Tan, Swee; Kyaw, Zabu; Liu, Wei; Ji, Yun; Ju, Zhengang; Zhang, Xueliang [LUMINOUS Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore) [LUMINOUS Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore); LUMINOUS Centre of Excellence for Semiconductor Lighting and Displays, School of Physical and Mathematical Sciences, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore); Wei Sun, Xiao, E-mail: EXWSUN@ntu.edu.sg [LUMINOUS Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore); LUMINOUS Centre of Excellence for Semiconductor Lighting and Displays, School of Physical and Mathematical Sciences, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore); Department of Electronics and Electrical Engineering, South University of Science and Technology of China, Shenzhen, Guangdong 518055 (China); Volkan Demir, Hilmi, E-mail: VOLKAN@stanfordalumni.org [LUMINOUS Centre of Excellence for Semiconductor Lighting and Displays, School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore); LUMINOUS Centre of Excellence for Semiconductor Lighting and Displays, School of Physical and Mathematical Sciences, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore (Singapore); Department of Electrical and Electronics, UNAM-Institute of Material Science and Nanotechnology, Bilkent University, Ankara TR-06800 (Turkey); Department of Physics, UNAM-Institute of Material Science and Nanotechnology, Bilkent University, Ankara TR-06800 (Turkey)

    2013-12-23

    Here, GaN/Al{sub x}Ga{sub 1-x}N heterostructures with a graded AlN composition, completely lacking external p-doping, are designed and grown using metal-organic-chemical-vapour deposition (MOCVD) system to realize three-dimensional hole gas (3DHG). The existence of the 3DHG is confirmed by capacitance-voltage measurements. Based on this design, a p-doping-free InGaN/GaN light-emitting diode (LED) driven by the 3DHG is proposed and grown using MOCVD. The electroluminescence, which is attributed to the radiative recombination of injected electrons and holes in InGaN/GaN quantum wells, is observed from the fabricated p-doping-free devices. These results suggest that the 3DHG can be an alternative hole source for InGaN/GaN LEDs besides common Mg dopants.

  3. Lasing characteristics of GaSb/GaAs self-assembled quantum dots embedded in an InGaAs quantum well

    E-Print Network [OSTI]

    Jalali. Bahram

    Center for High Technology Materials, University of New Mexico, 1313 Goddard SE, Albuquerque, New Mexico, New Mexico 87545 Received 26 February 2007; accepted 1 June 2007; published online 28 June 2007 intriguing optoelectronic device possibilities on GaAs substrates including lasers, detectors, or solar cells

  4. A 3-10 GHZLCR-matched Power Amplifier using Flip-Chip Mounted AlGaN/GaN HEMTs

    E-Print Network [OSTI]

    York, Robert A.

    amplifier using GaN- HEMTs-on-Sapphire. I INTRODUCTION GaN HEMTs have enormous potential for realizing high-power Traveling Wave Power Amplifier circuit (TWPA)[1][2] for realization of wideband power amplifiersWE4A-5 A 3-10 GHZLCR-matched Power Amplifier using Flip-Chip Mounted AlGaN/GaN HEMTs Jane J

  5. Intermixing of InGaAs/GaAs Quantum Well Using Multiple Cycles Annealing Cu-doped SiO2

    SciTech Connect (OSTI)

    Hongpinyo, V; Ding, Y H; Dimas, C E; Wang, Y; Ooi, B S; Qiu, W; Goddard, L L; Behymer, E M; Cole, G D; Bond, T C

    2008-06-11

    The authors investigate the effect of intermixing in InGaAs/GaAs quantum well structure using Cu-doped SiO{sub 2}. The incorporation of Cu into the silica film yields larger bandgap shift than typical impurity-free vacancy diffusion (IFVD) method at a lower activation temperature. We also observe enhancement of the photoluminescence (PL) signal from the intermixed InGaAs/GaAs quantum well structure after being cycle-annealed at 850 C.

  6. Metamorphic GaAsP buffers for growth of wide-bandgap InGaP solar cells J. Simon,1,a

    E-Print Network [OSTI]

    Haller, Gary L.

    . INTRODUCTION Triple-junction metamorphic solar cells have reached ef- ficiencies as high as 41.1% by combiningMetamorphic GaAsP buffers for growth of wide-bandgap InGaP solar cells J. Simon,1,a S. Tomasulo,1 P-yP solar cells. Tensile-strained GaAsxP1-x buffers grown on GaAs using unoptimized conditions

  7. FIRST DEMONSTRATION OF MONOLITHIC InP-BASED InAlAs/InGaAsP/InGaAs TRIPLE JUNCTION SOLAR CELLS

    E-Print Network [OSTI]

    Atwater, Harry

    FIRST DEMONSTRATION OF MONOLITHIC InP-BASED InAlAs/InGaAsP/InGaAs TRIPLE JUNCTION SOLAR CELLS RobynAlAs/InGaAsP/InGaAs triple junction solar cell grown on InP substrate. X-ray diffraction characterization shows high quality solar cell materials. Preliminary 1-sun AM1.5D testing of the triple junction solar cell shows promising

  8. Characterization of Cu(In,Ga)Se2 (CIGS) films with varying gallium ratios

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Claypoole, Jesse; Peace, Bernadette; Sun, Neville; Dwyer, Dan; Eisaman, Matthew D.; Haldar, Pradeep; Efstathiadis, Harry

    2015-09-05

    Cu(In1-x,Gax)Se2 (CIGS) absorber layers were deposited on molybdenum (Mo) coated soda-lime glass substrates with varying Ga content (described as Ga/(In+Ga) ratios) with respect to depth. As the responsible mechanisms for the limitation of the performance of the CIGS solar cells with high Ga contents are not well understood, the goal of this work was to investigate different properties of CIGS absorber films with Ga/(In+Ga) ratios varied between 0.29 and 0.41 (as determined by X-ray florescence spectroscopy (XRF)) in order to better understand the role that the Ga content has on film quality. The Ga grading in the CIGS layer hasmore »the effect causing a higher bandgap toward the surface and Mo contact while the band gap in the middle of the CIGS layer is lower. Also, a wider and larger Ga/(In+Ga) grading dip located deeper in the CIGS absorber layers tend to produce larger grains in the regions of the films that have lower Ga/(In+Ga) ratios. It was found that surface roughness decreases from 51.2 nm to 41.0 nm with increasing Ga/(In+Ga) ratios. However, the surface roughness generally decreases if the Ga grading occurs deeper in the absorber layer.« less

  9. Radiation damage of GaAs thin-film solar cells on Si substrates

    SciTech Connect (OSTI)

    Itoh, Y.; Yamaguchi, M.; Nishioka, T.; Yamamoto, A.

    1987-01-15

    1-MeV electron irradiation damages in GaAs thin-film solar cells on Si substrates are examined for the first time. Damage constant for minority-carrier diffusion length in GaAs heteroepitaxial films on Si substrates is found to be the same as that in GaAs homoepitaxial films on GaAs substrates. This agreement suggests that GaAs/Si has the same defect introduction rate with radiation as GaAs/GaAs. The degradation of GaAs solar cells on Si with electron irradiation is less than that of GaAs solar cells on GaAs, because in the present, GaAs films on Si substrates have lower minority-carrier diffusion length compared to GaAs films on GaAs and these films are insensitive to radiation. The p/sup +/-p/sup +/-n AlGaAs-GaAs heteroface solar cell with junction depth of about 0.3 ..mu..m is concluded to be useful for a high-efficiency and radiation-resistant solar cell fabricated on a Si substrate.

  10. Laser Gain and Threshold Properties in Compressive-Strained and Lattice-Matched GaInNAs/GaAs Quantum Wells

    SciTech Connect (OSTI)

    Chow, W.W.; Jones, E.D.; Modine, N.A.; Allerman, A.A.; Kurtz, S.R.

    1999-08-04

    The optical gain spectra for compressive-strained and lattice-matched GaInNAs/GaAs quantum wells are computed using a microscopic laser theory. From these spectra, the peak gain and carrier radiative decay rate as functions of carrier density are determined. These dependences allow the study of lasing threshold current density for different GAInNAs/GaAs laser structures.

  11. Metal contacts on ZnSe and GaN

    SciTech Connect (OSTI)

    Duxstad, K J [Univ. of California, Berkeley, CA (United States). Materials Science and Mineral Engineering

    1997-05-01

    Recently, considerable interest has been focused on the development of blue light emitting materials and devices. The focus has been on GaN and ZnSe, direct band gap semiconductors with bands gaps of 3.4 and 2.6 eV, respectively. To have efficient, reliable devices it is necessary to have thermally and electrically stable Ohmic contacts. This requires knowledge of the metal-semiconductor reaction behavior. To date few studies have investigated this behavior. Much information has accumulated over the years on the behavior of metals on Si and GaAs. This thesis provides new knowledge for the more ionic wide band gap semiconductors. The initial reaction temperatures, first phases formed, and phase stability of Pt, Pd, and Ni on both semiconductors were investigated. The reactions of these metals on ZnSe and GaN are discussed in detail and correlated with predicted behavior. In addition, comparisons are made between these highly ionic semiconductors and Si and GaAs. The trends observed here should also be applicable to other II-VI and III-Nitride semiconductor systems, while the information on phase formation and stability should be useful in the development of contacts for ZnSe and GaN devices.

  12. Contribution of alloy clustering to limiting the two-dimensional electron gas mobility in AlGaN/GaN and InAlN/GaN heterostructures: Theory and experiment

    SciTech Connect (OSTI)

    Ahmadi, Elaheh; Mishra, Umesh K. [Electrical and Computer Engineering Department, University of California, Santa Barbara, California 93106 (United States); Chalabi, Hamidreza [Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305 (United States); Kaun, Stephen W.; Shivaraman, Ravi; Speck, James S. [Materials Department, University of California, Santa Barbara, California 93106 (United States)

    2014-10-07

    The influence of alloy clustering on fluctuations in the ground state energy of the two-dimensional electron gas (2DEG) in AlGaN/GaN and InAlN/GaN heterostructures is studied. We show that because of these fluctuations, alloy clustering degrades the mobility even when the 2DEG wavefunction does not penetrate the alloy barrier unlike alloy disorder scattering. A comparison between the results obtained for AlGaN/GaN and InAlN/GaN heterostructures shows that alloy clustering limits the 2DEG mobility to a greater degree in InAlN/GaN heterostructures. Our study also reveals that the inclusion of an AlN interlayer increases the limiting mobility from alloy clustering. Moreover, Atom probe tomography is used to demonstrate the random nature of the fluctuations in the alloy composition.

  13. Dynamic magnetization states of a spin valve in the presence of dc and ac currents: Synchronization, modification, and chaos

    E-Print Network [OSTI]

    Li, Charles

    Dynamic magnetization states of a spin valve in the presence of dc and ac currents: Synchronization and numerical calculations of dynamic magnetization states of a spin valve in the presence of dc and ac currents are expected to appear. In this paper, we consider a simple spin valve as a model system to study the problem

  14. Abstract--Environmentally friendly technologies such as photovoltaics and fuel cells are DC sources. In the current power

    E-Print Network [OSTI]

    Tolbert, Leon M.

    Abstract--Environmentally friendly technologies such as photovoltaics and fuel cells are DC sources in pollution [1]. The most well-known green technologies include photovoltaics and wind turbines. Although fuel, fuel cells and photovoltaics, produce direct current (DC). Currently, power system infrastructures

  15. Superconductivity for Electric Systems Annual Peer Review Washington, DC July 27-29, 2004. OAK RIDGE NATIONAL LABORATORY

    E-Print Network [OSTI]

    Superconductivity for Electric Systems Annual Peer Review Washington, DC ­ July 27-29, 2004. OAK RIDGE NATIONAL LABORATORY U. S. DEPARTMENT OF ENERGY American Superconductor Corporation U. Schoop, M. W&D support #12;Superconductivity for Electric Systems Annual Peer Review Washington, DC ­ July 27-29, 2004

  16. Optimal Demand Response in DC Distribution Networks Hamed Mohsenian-Rad, Member, IEEE and Ali Davoudi, Member, IEEE

    E-Print Network [OSTI]

    Mohsenian-Rad, Hamed

    Optimal Demand Response in DC Distribution Networks Hamed Mohsenian-Rad, Member, IEEE and Ali first present an optimization-based foundation for demand response in DC distribution networks. Then, we devise a pricing mechanism to enforce optimal demand response in a distributed fashion. Simulation

  17. Jaworski Liquid metal PSI science and component development FESAC Meeting, Washington DC July 8-10, 2014

    E-Print Network [OSTI]

    Jaworski ­ Liquid metal PSI science and component development ­ FESAC Meeting, Washington DC ­ July 8-10, 2014 Liquid metal plasma-material interaction science and component development MA Jaworski on behalf of the Liquid Metal Plasma-Facing Component working group FESAC Meeting, Washington DC ­ July 8

  18. DC WRRC Report No. 127 GROUND WATER RESOURCE ASSESSMENT STUDY FOR

    E-Print Network [OSTI]

    District of Columbia, University of the

    project: James Collier - DCRA Water Resources Management Division Mohsin Siddique - DCRA Water Quality DRILLING AND FIELD OPERATIONS REPORT FOR THE GROUP B WELLS D.C. WATER RESOURCES RESEARCH CENTER University: Well Drilling and Field Operations Report - Group B Wells DATE: July 1993 AUTHOR(S): Jutta Schneider

  19. Strontium Titanate DC Electric Field Switchable and Tunable Bulk Acoustic Wave Solidly Mounted Resonator

    E-Print Network [OSTI]

    York, Robert A.

    Strontium Titanate DC Electric Field Switchable and Tunable Bulk Acoustic Wave Solidly Mounted.3 0/0. Index Terms - Acoustic resonators, bulk acoustic wave devices, delay filters, ferroelectric,4] that can be exploited to realize voltage-switchable bulk-acoustic wave (BAW) devices for RF applications [5

  20. dc electric field tunable bulk acoustic wave solidly mounted resonator using SrTiO3

    E-Print Network [OSTI]

    York, Robert A.

    dc electric field tunable bulk acoustic wave solidly mounted resonator using SrTiO3 G. N. SaddikTiO3 solidly mounted bulk acoustic wave resonator has been designed, fabricated, and tested of Physics. DOI: 10.1063/1.2759464 Thin film bulk acoustic wave resonators FBARs have been in use by research