| Q2 Known Good Substrates Technical Report |
05-May-2009 |
11 pages |
| Authors:
Eric Carlson; Mark Loboda; Gilyong Chung; Rebecca Lauer; DOW CORNING CORP MIDLAND MI
|
 | The Known Good Substrates (KGS) Phase III program was initiated 29 September 2008. Wafer, epitaxy, modeling and metrology work has been the main focus of efforts in Q2. This technical report summarizes the progress by all team members against the tasks and milestones. |
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| Growth of Low Defect Density Gallium Nitride (GaN) Films on Novel Tantalum Carbide (TaC) Substrates for Improved Device Performance |
May-2009 |
34 pages |
| Authors:
M A Derenge; K A Jones; K W Kirchner; T S Zheleva; R D Vispute; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
|
| To potentially improve device performance, we attempted to grow gallium nitride (GaN) films with better crystalline quality (fewer mismatch dislocations) using a tantalum carbide (TaC) substrate, which is more closely lattice matched to GaN than currently used substrates. We created the TaC substrate, using pulse laser deposition (PLD) of TaC onto (0001) SiC substrates at tilde 1000 deg C, and grew GaN films, using metal organic chemical vapor deposition (MOCVD). ... |
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| Hawaii Energy and Environmental Technologies (HEET) Initiative |
May-2009 |
208 pages |
| Authors:
Michael J Jr; Richard E Rocheleau; Guido Bender; Maheboob Virji; Antal; Michael J Cooney; Bor Y Liaw; Stephen M Masutani; HAWAII UNIV HONOLULU
|
| This report covers efforts by the Hawaii Natural Energy Institute of the University of Hawaii under the ONR-funded HEET Initiative that addresses critical technology needs for exploration/utilization of seabed methane hydrates and development/testing of advanced fuel cells and fuel cell systems. Methane hydrates work included: hydrate thermochemistry and kinetics; environmental impacts of methane release from seafloor hydrates; hydrate engineering applications; and international collaborative R&D. In the fuel cell area, accomplishments ... |
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| An Extensive X-ray Computed Tomography Evaluation of a Fully Penetrated Encapsulated SiC MMC Ballistic Panel |
Apr-2009 |
20 pages |
| Authors:
William H Green; Robert H Carter; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
|
| X-ray computed tomography (XCT) is an important nondestructive evaluation technique for revealing the spatial distribution of ballistically induced damage in ceramics. The level of detection and resolution of damage depends on the size of the sample and the parameters of the XCT approach (e.g., focal spot size, magnification, etc.). Previous and ongoing work in this area includes assessment of ballistically induced damage in both individual ceramic targets and ceramic armor ... |
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| An Elegant Low-cost Materials Solution for Achieving Low Insertion Loss, Affordable Tunable Filters for Next Generation Mobile Communications Platforms |
Apr-2009 |
18 pages |
| Authors:
M W Cole; E Ngo; R J Tan; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
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| The effect ultraviolet (UV)-assisted annealing on the structural, dielectric, and insulating properties of barium strontium titanate (BST) thin films was investigated. The material properties of BST films, prepared by RF sputter deposition, annealed via conventional thermal annealing and UV-assisted thermal annealing process protocols were compared and evaluated. The x-ray diffraction results showed contracted lattice constants and enhanced crystallinity for the RF sputtered BST films annealed via the UV-assist treatment. Isothermal-temporal ... |
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| Terahertz Diode Development |
23-Mar-2009 |
24 pages |
| Authors:
Lester F Eastman; Quentin Diduck; Barbaros Aslan; CORNELL UNIV ITHACA NY OFFICE OF SPONSORED PROGRAMS
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| The research efforts to develop a high-efficiency, moderate power THz device are discussed. The device structure is based upon the crystalline properties of GaN and its ability to handle large power and high fields. Physical device models were developed that include thermal and electrical simulations. Several device structures were produced in conjunction with the model development Initial negative differential conduction results from fabricated devices are presented as are the designs ... |
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| Biofilm Formation by a Metabolically Versatile Bacterium |
19-Mar-2009 |
8 pages |
| Authors:
Caroline S Harwood; WASHINGTON UNIV SEATTLE OFFICE OF SPONSORED PROGRAMS
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| Rhodopseudomonas palustris is a photosynthetic bacterium that has good potential as a biocatalyst for the production of hydrogen gas, a biofuel. With this award we conducted basic studies to facilitate the development of a process where R. palustris cells grown on surfaces as biofilms, produce hydrogen gas using energy from the sun and electrons from agricultural waste. We characterized five new Rhodopseudomonas genome sequences and isolated and described R. palustris ... |
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| A New Method for Growth and Analysis of Next-generation Infrared (IR) Detector Materials |
Mar-2009 |
20 pages |
| Authors:
John D Demaree; Stefan Svensson; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
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| This report describes the development of a new analysis and crystal growth method for next generation infrared materials, namely, dilute nitride III-V semiconductors, which may be used in future low-cost night vision systems. The key to this method is isotopic enrichment of nitrogen-15 during material growth via molecular beam epitaxy, which allows enhanced detection of nitrogen using resonant nuclear reaction analysis. We synthesized films of gallium arsenide nitride (GaAsN) using ... |
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| The Effects of Temperature and Electron Radiation on the Electrical Properties of AlGaN/GaN Heterostructure Field Effect Transistors |
Mar-2009 |
120 pages |
| Authors:
Jeffrey T Moran; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
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| AlGaN/GaN Heterostructure Field Effect Transistors (HFETs) have come under increased study, in recent years, owing to their highly desirable material and electrical properties, ruggedness, and survivability even during and after exposure to extreme temperature and radiation environments. These devices or similar devices constructed of AlGaN and/or GaN materials are being researched for their potential applications in many military and space based systems. In this study, unpassivated and SiN passivated Al(0.27)Ga(0.73)N/GaN ... |
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| Combined Experimental and Computational Study of Plastic Deformation in Crystals and Bicrystals for the Development of Multi-Length Scale Constitutive Models |
28-Feb-2009 |
11 pages |
| Authors:
Jeffrey W Kysar; COLUMBIA UNIV NEW YORK DEPT OF MECHANICAL ENGINEERING
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| The experimental effort concentrated on wedge indentation under quasistatic conditions in single crystals of Ni, Cu, and Al as well as bicrystals of Al. Wedge indenters with included angles of 60-deg, 90-deg, and 120-deg were used in the single crystals and an included angle of 90-deg was used near the train boundary of the Al bicrystal. the lattice rotations were experimentally determined via EBSD. The experimental results were processed to ... |
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| Comparative Environmental Toxicology Assessment of White and Red Phosphorous Munitions, Eagle River Flats Firing Range, Ft. Richardson, Alaska |
26-Feb-2009 |
16 pages |
| Authors:
William S Eck; M S Johnson; ARMY CENTER FOR HEALTH PROMOTION AND PREVENTIVE MEDICINE ABERDEEN PROVING GROUND MD
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| Eagle River Flats Firing Range is used as an impact area by troops training at Ft. Richardson, AK. Firing of white phosphorous munitions was suspended in February 1990 because of mortality to migratory waterfowl. The Commander of Ft. Richardson is seeking to begin firing red phosphorous munitions to support troop training. This report assesses the comparative toxicity of white and red phosphorous munitions with special consideration for waterfowl and other ... |
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| Investigation on the Solubility of GaN in Supercritical Ammonia Containing Acidic, Neutral, and Some Basic Mineralizers |
19-Feb-2009 |
5 pages |
| Authors:
Dirk Ehrentraut; TOHOKU UNIV SENDAI (JAPAN)
|
| The ammonothermal growth technique to fabricate large size (2 inch) gallium nitride (GaN) crystals has recently seen increased interest due to the achievements in the technique published over the last 2-3 years. The first ever 2 inch GaN bulk crystal, to be reported in the April 2009 issue of MRS Bulletin, holds the great promise that ammonothermally produced GaN may become an important GaN substrate material due to the superior ... |
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| Preparation and Applications of Active Nanostructures as Biosensors |
04-Feb-2009 |
4 pages |
| Authors:
Chung-Yuan Mou; Tien-Sung Lin; NATIONAL TAIWAN UNIV TAIPEI (TAIWAN) DEPT OF CHEMISTRY
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| This project synthesized active mesoporous silicas with nanospaces to immobilize proteins or fragments of DNA to determine their biosensing utility via electrochemical and spectroscopic methods. |
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| Four-Channel Threshold Detector With Optical Isolation |
Feb-2009 |
26 pages |
| Authors:
Mark R Morgenstern; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
|
| The four-channel window comparator discussed in this report is a safety switch that can be used to limit a range of test variables such as voltages, currents, temperatures or other values that can be scaled to a voltage within +-13 V. This device is simple, reliable, rugged, and requires no external control hardware or software. This module is scalable and reconfigurable to support nearly any test apparatus. |
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| Comparison of Slip Cast to Hot Pressed Boron Carbide |
Feb-2009 |
14 pages |
| Authors:
T Sano; E S Chin; B Paliwal; M W Chen; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
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| To meet the possible increase in future demand for armor materials, an increase in the throughput during manufacturing is necessary. One possibility is the use of the slip casting and sintering technique to form ceramic armor compacts as an alternative to current hot pressing techniques. Dynamic uniaxial compression tests with the Kolsky bar were conducted on two types of slip cast boron carbide, and compared with results from the standard ... |
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| Tunable, Room Temperature Light-emitting Diodes Based on Strained Si/SiGe Heterostructures |
24-Jan-2009 |
5 pages |
| Authors:
G Sun; H H Cheng; R A Soref; NATIONAL TAIWAN UNIV TAIPEI CENTER FOR CONDENSED MATTER SCIENCES
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| This is the report of a project to engineer SiGe/Si heterostructures for a type-I band alignment in which the emission intensity at around 1 micrometer is enhanced over conventional Si-based diodes, and to develop sight-emitting diodes based on the novel type-I SiGe/Si heterostructure. |
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| Wavelength Tuning Limitations in Optically Pumped Type-II Antimonide Lasers |
07-Jan-2009 |
6 pages |
| Authors:
A P Ongstad; R Kaspi; G C Dente; M L Tilton; J R Chavez; R Barresi; AIR FORCE RESEARCH LAB KIRTLAND AFB NM
|
| In this paper, we examine the wavelength tuning limitations of type-II antimonide lasers containing InAs/InGaSb/InAs quantum wells. Wavelength tuning is accomplished by varying the thickness of the InAs electron wells while keeping all else fixed. In principle, these wells can be tuned from lambda approximately equal 2.5 m out to far IR wavelengths by increasing the thickness of the InAs layers. However, a practical upper limit of lambda approximately equal ... |
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| Near Field Scanning Optical Microscopy (NSOM) of Nano Devices |
Dec-2008 |
77 pages |
| Authors:
Chun H Low; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| This thesis aims to investigate the optical properties of nano-devices using the technique of Near-Field Scanning Optical Microscopy (NSOM). A unique set-up to perform Atomic Force Microscopy (AFM) and NSOM simultaneously in a scanning electron microscope (SEM) to collect spatially resolved luminescence and image transport on nano-scale structures, particularly nanowires, will allow direct determination of transport parameters, such as minority carrier mobility and diffusion length that are vital to the ... |
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| Evaluation of the Snap Sampler for Sampling Ground Water Monitoring Wells for Inorganic Analytes |
Dec-2008 |
74 pages |
| Authors:
Louise V Parker; Nathan D Mulherin; Gordon E Gooch; ENGINEER RESEARCH AND DEVELOPMENT CENTER HANOVER NH COLD REGIONS RESEARCH AND ENGINEERING LAB
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| Abstract: Laboratory studies and a field demonstration were conducted to determine the ability of the Snap Sampler to recover representative concentrations of inorganic analytes, including metals, from ground water. For the laboratory studies, concentrations of analytes in Snap Sampler samples were compared with concentrations of the analytes in samples collected from a standpipe (i.e., control samples). These studies clearly demonstrated that Snap Sampler concentrations were comparable to control sample concentrations. ... |
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| Aptamer Selection Express: A Novel Method for Rapid Single-Step Selection and Sensing of Aptamers |
Dec-2008 |
10 pages |
| Authors:
Maomian Fan; Shelly Roper; Carrie Andrews; Amity Allman; John Bruno; Jonathan Kiel; CONCEPTUAL MINDWORKS INC SAN ANTONIO TX
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| This article describes a new DNA capture element (DCE) sensing system, based on the quenching and dequenching of a double-stranded aptamer. This system shows very good sensitivity and thermal stability. While quenching, dequenching, and separating the DCE systems made from different aptamers (all selected by SELEX), an alternative method to rapidly select aptamers was developed the Aptamer Selection Express (ASExp). This process has been used to select aptamers against different ... |
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| Efficient THZ Source Based on Cascaded Optical Down-Conversion in Orientation-Patterned GaAs Structures |
20-Nov-2008 |
34 pages |
| Authors:
Xiaojun Yu; Walter Hurlbut; Vladimir Kozlov; James Harris; Anjie Lin; Paulina Kuo; Joe Schaar; Martin Fejer; Konstantin Vodopyanov; Candace Lynch; David Bliss; Yun-Shik Lee; STANFORD UNIV CA EDWARD L GINZTON LAB OF PHYSICS
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| The goal of this DARPA TIFT project was to demonstrate an efficient room temperature source for THz imaging systems based on optical down-conversion in an orientation-patterned GaAs microstructure, incorporated into an optical resonant cavity, and pumped by a compact solid state laser. The main achievements are: (1) quasi-phase-matched (QPM) GaAs microstructures with periodic reversal of crystalline orientation, including orientation-patterned GaAs (OPGaAs), diffusion-bonded GaAs (DB-GaAs) and optically-contacted GaAs (OC-GaAs) suitable for ... |
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| High-Pressure Freezing, Crystal Structure Studies and Si-CF3 Bond Polarizability of Trimethyl(trifluoromethyl)silane (Postprint) |
Nov-2008 |
7 pages |
| Authors:
Ashwani Vij; Anna Olejniczak; Andrzej Katrusiak; ADAM MICKIEWICZ UNIV POZNAN (POLAND)
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| Trimethyl(trifluoromethyl)silane, (CH3)3SiCF3, has been in situ pressure frozen in a diamond anvil cell and its structure determined at 0.90(5) GPa/296 K by single-crystal X-ray diffraction. The crystal is monoclinic, space group P21/m, with the molecules lying on crystallographic mirror planes. The CH3 and CF3 groups assume the fully staggered conformation. The 14-fold coordination scheme of the molecules is similar to those in (CH3)3SiCl polymorphs, but different from that in crystalline ... |
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| Microstructure and Properties of WC Spheres |
Nov-2008 |
32 pages |
| Authors:
Jeffrey J Swab; Justin Pritchett; Andrew A Wereszczak; Osama M Jadaan; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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| Tungsten carbide (WC) spheres are used as projectiles to study the ballistic performance of armor materials and systems. In order to properly understand and model the interaction between the projectile and the armor, it is necessary to have properties of both. In this study, the physical and mechanical properties of two commercially available WC spheres (nominally 0.25 inch in diameter) used in some ballistic impact studies were determined. One WC ... |
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| Carbon Dioxide Corrosion and Acetate: A Hypothesis on the Influence of Microorganisms |
Nov-2008 |
7 pages |
| Authors:
Brenda J Little; Joseph M Suflita; Tommy J Phelps; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS OCEANOGRAPHY DIV
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| It is our hypothesis that fermentative acetogenic, and sulfate-reducing bacteria residing in pipeline facilities can influence corrosion through the production of carbon dioxide and acetate under the prevailing anaerobic conditions. The exacerbation of carbon dioxide corrosion of carbon steel in the presence of acetic acid is a well-known phenomenon in the oil industry. Both chemical compounds can be produced and consumed by microorganisms during the anaerobic biodegradation of organic matter-- ... |
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| Conference on the Physics, Chemistry and Biology of Water (3rd) Held in West Dover, Vermont on October 16-19, 2008 (Abstracts) |
27-Oct-2008 |
34 pages |
| Authors:
Thomas Lowell; VERMONT PHOTONICS TECHNOLOGIES CORP BELLOWS FALLS VT
|
| The 3rd Annual Conference on the Physics, Chemistry and Biology of Water was held in West Dover, Vermont October 16th thru 19th, 2008. The conference was organized by Vermont Photonics Technologies Corporation of Bellows Falls, Vermont, and was attended by an international group of 51 scientists who presented 31 papers during the 4 days. The cost of organizing this event was approximately $43,000, offset by attendance fees, sponsorship by 2 ... |
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| Perchlorate Contamination of Drinking Water: Regulatory Issues and Legislative Actions |
16-Oct-2008 |
7 pages |
| Authors:
Mary Tiemann; LIBRARY OF CONGRESS WASHINGTON DC CONGRESSIONAL RESEARCH SERVICE
|
| Perchlorate is the explosive component of solid rocket fuel, fireworks, road flares, and other products. Used heavily by the Department of Defense (DOD) and related industries, perchlorate also occurs naturally and is present in some organic fertilizer. This soluble, persistent compound has been detected in drinking water supplies, especially in California. It also has been found in milk and many foods. Because of this widespread occurrence, concern over the potential ... |
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| Silica Nanofiber Combat Hemostat (SINCH) |
13-Oct-2008 |
24 pages |
| Authors:
Robert H Daniels; Esther Li; Oscar Abilez; Chengpei Xu; Christopher Zarins; NANOSYS PALO ALTO CA
|
| We screened a panel of nanomaterials and identified high aspect ratio silica nanofibers (>100) as the best promoter of coagulation in vitro. These materials require combination with a carrier in order to provide adequate handling characteristics. We evaluated a panel of carrier material candidates for their ability to improve handling, act as a bulking agent, and improve hemostatic performance. Preliminary tests identified a combination of silica nanofibers and glass microspheres ... |
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| Flux Pinning Enhancement in YBa2Cu3O7-x Films with BaSnO3 Nanoparticles |
01-Oct-2008 |
7 pages |
| Authors:
P N Barnes; Chakrapani V Varanasi; J Burke; L Brunke; I Maartense; T J Haugan; E A Stinzianni; K A Dunn; P Haldar; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE
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| Nanoparticles of BaSnO3 were incorporated into YBa2Cu3O7-x (YBCO) films on LaAlO3 substrates for magnetic flux pinning enhancements. More than an order of magnitude improvement in the high field magnetization Jc at 6 T at 77 K was observed as compared to regular YBCO films. The irreversibility field (Hirr) was increased to 8.5 T at 77 K and to 13.4 T at 65 K. The in-field transport current measurements confirmed an ... |
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| Visualization of Coupling Current Paths in Striated YBCO-Coated Conductors at Frequencies up to 400 HZ |
01-Oct-2008 |
7 pages |
| Authors:
E Demencik; P Usak; S Takacs; I Vavra; M Polak; G A Levin; P N Barnes; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE
|
| The magnetic flux density component perpendicular to the broad tape face was mapped by miniature Hall probes in the vicinity of a striated YBCO-coated tape at frequencies of external magnetic field from 21 to 400 Hz, applied perpendicularly to the tape surface. For reasons of modeling the coupling current behaviour in tapes with a conductive substrate, we amplified the coupling current-amplitude by soldering 25 microns thick copper foil on the ... |
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| Extrinsic Substrate Orientation Dependence of Ferromagnetism in (Ga,Mn)As Digital Ferromagnetic Heterostructures |
01-Oct-2008 |
13 pages |
| Authors:
M J Wilson; G Xiang; B L Sheu; P Schiffer; N Samarth; PENNSYLVANIA STATE UNIV UNIVERSITY PARK OFFICE OF SPONSORED PROGRAMS
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| We describe the structural and magnetic properties of digital ferromagnetic heterostructures of (Ga,Mn)As grown on (001), (311), (201) and (110) GaAs surfaces. Our measurements show a systematic variation of the Curie temperature with epitaxial orientation for samples with a nominally identical structure. Control measurements of randomly alloyed (Ga,Mn)As grown on these substrates show identical trends in Curie temperature, suggesting that the substrate orientation plays a strong role in the formation ... |
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| Microstructure-Evolution and Reliability Assessment Tool for Lead-Free Component Insertion in Army Electronics |
Oct-2008 |
181 pages |
| Authors:
Krishna Tunga; Suresh K Sitaraman; GEORGIA INST OF TECH ATLANTA OFFICE OF CONTRACT ADMINISTATION
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| This work aims to understand the reliability of Sn-Ag-Cu solder interconnects used in plastic ball grid array (PBGA) packages using microstructure evolution, laser moire interferometry and finite-element modeling. A particle coarsening based microstructure evolution of the solder joint material during thermal excursions was studied for extended periods of time lasting for several months. The microstructure evolution and particle coarsening was quantified, and acceleration factors were determined between long-term field-use conditions ... |
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| Solid State Quantum Computer in Silicon |
30-Sep-2008 |
47 pages |
| Authors:
R G Clark; A S Dzurak; M Y Simmons; D N Jamieson; S Prawer; L C Hollenberg; J C McCallum; NEW SOUTH WALES UNIV SYDNEY (AUSTRALIA) RESEARCH OFFICE GRANTS SUPPORT SECTION
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| A Si:P electron-spin qubit architecture was developed in 2008, based upon research outcomes over the four-year QCCM grant. Single-shot spin readout will proceed via spin-dependent tunneling to a Si MOS rf-SET, which we have demonstrated to posses charge sensitivities equal to or better than Al rf-SETs. Spin manipulation will occur using local electron-spin resonance (ESR), which we have used to observe hyperfine-split electron spin resonances in P-doped Si MOSFETs. This ... |
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| Biotic - Abiotic Interface Between they Body and the Artificial Limb |
29-Sep-2008 |
29 pages |
| Authors:
Kenneth H Church; SCIPERIO INC ORLANDO FL
|
| Intraosseous transcutaneous amputation prostheses (ITAPs) may be able to overcome the problems that stem from the nonuniform distribution of pressure seen in the conventional stump-socket prosthetic replacement devices. While transcutaneous devices have had limited success in amputees. By optimizing the attachment of the skin to the prosthetic, ITAPs may become clinically viable options. Our team has developed a modified titanium construct with a specially machined surface to increase the adherence ... |
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| Hydrophobic Silsesquioxane Nanoparticles and Nanocomposite Surfaces |
23-Sep-2008 |
13 pages |
| Authors:
Darrell Marchant; Ashwani Vij; Isha Vij; Scott Iacono; Joseph M Mabry; Brent D Viers; Wade W Grabow; Patrick N Ruth; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
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| Fluorinated Polyhedral Oligomeric Silsesquioxanes are hydrophobic nanoparticles. One compound, FD8T8, is ultrahydrophobic, possessing a water contact angle of 154-deg. This is believed to be the most hydrophobic and lowest surface tension crystalline substance known. Analysis of the x-ray crystal structure indicates a large number of Si-deg F contacts may lead to ultrahydrophobicity. |
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| Development of Convergence Nanoparticles for Multi-Modal Bio-Medical Imaging |
18-Sep-2008 |
18 pages |
| Authors:
Jinwoo Cheon; YONSEI UNIV SEOUL (KOREA SOUTH) DEPT OF CHEMISTRY
|
| The purpose of this project is to develop a novel, highly versatile, multi-functional convergence nanoparticle system for their advanced biomedical applications. Inorganic nanoparticles are now emerging as a promising candidate to revolutionize current science and technology. By utilizing inorganic nanoparticles, it is possible to have the ability to control physical/chemical properties of materials as we desire, which is not allowed in current technology. Furthermore, these inorganic nanoparticles exhibit improved physical/chemical ... |
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| Low Temperature Photoluminescence and Leakage Current Characteristics of InAs-GaSb Superlattice Photodiodes |
01-Sep-2008 |
20 pages |
| Authors:
P A Folkes; J Little; S Svensson; K Olver; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
|
| We report the results of a study of the temperature-dependent photoluminescence (PL) and leakage current characteristics of a set of type II idium arsenide (InAs)-gallium antimonide (GaSb) superlattice (SL) photodiode structures. We find that the PL efficiency of high-quality structures is determined by Shockley-Read and trap-assisted tunneling nonradiative recombination processes. Our results suggest a possible correlation between trap-assisted tunneling in some SL structures and an anomalous decrease in the PL ... |
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| Prediction of Groundwater Quality Down-gradient of In Situ Permeable Treatment Barriers and Fully-remediated Source Zones |
01-Sep-2008 |
127 pages |
| Authors:
ARIZONA STATE UNIV TEMPE
|
| In situ permeable treatment barriers (PTBs) are designed such that contaminated groundwater flows through an engineered treatment zone within which contaminants are eliminated or the concentrations are significantly reduced. These systems are often considered for the containment of dissolved contaminant plumes, or for controlling the discharge and larger-scale impact of dissolved contaminants from source zones to aquifers. Previous studies have concluded that a better understanding of the subsequent improvement in ... |
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| Materials Design Through Chemical Control of Precursors |
22-Aug-2008 |
11 pages |
| Authors:
Charles H El Winter; Hani M Kadri; Dezelah; Charles L IV; WAYNE STATE UNIV DETROIT MI OFFICE OF RESEARCH AND SPONSORED PROGRAMS
|
| Our research project that was supported by the Army Research Office sought to develop improved metal-organic film growth precursors for Pb- and Ba-containing materials, lanthanide-containing materials, and semiconductors that contain small clusters of magnetic elements within the semiconductor matrix. These materials encompass a broad range of military and civilian applications, and their successful development will literally change the way we live. More broadly, we sought to develop chemical insight into ... |
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| Qualification of Trivalent Chromate as a Hexavalent Chromate Alternative for Propellant and Cartridge Actuated Devices |
28-Jul-2008 |
62 pages |
| Authors:
Harry L Archer; NAVAL SURFACE WARFARE CENTER INDIAN HEAD DIV MD
|
| A low toxicity trivalent chromate conversion coating (TCP) over a zinc-phosphate conversion coat was qualified to replace toxic hexavalent chromate conversion coating (CCC) on zinc-nickel plated steel. Unpainted test panels exhibited at least 42 days of resistance to cyclic salt fog. These panels lasted at least 4 days when subjected to cyclic sulfur dioxide and cyclic salt fog testing with full red rust evident on the seventh day. Painted and ... |
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| Vapor-Phase Infrared Absorptivity Coefficient of BIS-(2-Chloroethyl) Sulfide |
01-Jul-2008 |
31 pages |
| Authors:
Alan C Samuels; H D Durst; Barry R Williams; Melissa S Hulet; Ronald W Miles; Frederic J Berg; Leslie McMahon; SCIENCE APPLICATIONS INTERNATIONAL CORP (SAIC) ABINGDON MD
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| We measured the vapor-phase absorptivity coefficient of the vesicant chemical warfare agent, bis-(2-chloroethyl) sulfide (HD), in the mid-infrared (4000-550/cm) at a spectral resolution of 0.125/cm. The HD used in the feedstock was subjected to a rigorous analysis by gas chromatography (GC) and NMR to verify its purity, and the vapor used to produce the composite spectrum was periodically sampled by GC. In this report, we describe the experimental method employed ... |
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| Background Pressure Effects on Internal and Near-field Ion Velocity Distribution of the BHT-600 Hall Thruster (Preprint) |
24-Jun-2008 |
10 pages |
| Authors:
Michael R Nakles; Hargus; William A Jr; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| Presented is a study of the effects of chamber background pressure on the ion axial velocity distribution within the discharge chamber and in the near-field of the Busek BHT-HD-600 xenon Hall effect thruster. Ion velocity distributions were measured along the acceleration channel centerline using laser-induced fluorescence of the 5d[4](sub 7/2)-6p[3](sub 5/2) xenon ion excited state transition. Measurements were taken at the lowest possible chamber background pressure and a pressure that ... |
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| The Effect of Radiation on the Electrical Properties of Aluminum Gallium Nitride/Gallium Nitride Heterostructures |
01-Jun-2008 |
176 pages |
| Authors:
John W McClory; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
|
| AlGaN/GaN Heterojunction Field Effect Transistors (HFETs) were irradiated at low temperature and the temperature dependent changes to drain current, gate current, capacitance, and transconductance were measured. The results were compared to the charge control model of the drain current and trap-assisted tunneling model of the gate current to determine the source of the radiation-induced changes. AlGaN/GaN HFETs demonstrated threshold voltage shifts and drain current changes after irradiation. After electron and ... |
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| Multi-scale Modeling of Proton Transport, Water Distribution, and Methanol Permeability in Proton Exchange Membranes (PEMs) |
26-May-2008 |
9 pages |
| Authors:
Stephen J Paddison; Mark E Tuckerman; ALABAMA UNIV IN HUNTSVILLE
|
| We have undertaken our multiscale modeling of proton exchange membranes through three simultaneous but distinct studies of perfluorosulfonic acid (PFSA) systems at different time and length scales: (1) hydrated morphology of PFSA membranes with dissipative particle dynamics (DPD) simulations; (2) classical MD simulations of the hydration and hydronium ion diffusion of the short-side chain (SSC) PFSA membrane; and (3) ab initio density functional theory Car-Parrinello MD simulations of model PFSA ... |
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| Type-II Superlattice for High Performance LWIR Detectors |
15-May-2008 |
27 pages |
| Authors:
Manijeh Razeghi; Binh-Minh Nguyen; Darin Hoffman; Pierre-Yves Delaunay; Ed Huang; NORTHWESTERN UNIV EVANSTON IL CENTER FOR QUANTUM DEVICES
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| We have studied and reported on the temperature dependant photoluminescence of Type-II InAs/GaSb superlattices. The PL spectrum gives precise information on the energy levels available to the electrons. The intensity of the PL signal depends on the rate of the radiative and non - radiative events that in turn depends on the density of the non radiative states. We look at the bangap dependence excitation intensity dependence of the Photoluminescence ... |
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| Polynitrogen/Nanoaluminum Surface Interactions (Challenge Project C2V) (Preprint) |
08-May-2008 |
8 pages |
| Authors:
Jerry A Boatz; Dan C Sorescu; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
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| First-principles density functional theory (DFT) calculations using the generalized gradient approximation (GGA) have been performed to study the adsorption of a series of all-nitrogen and high-nitrogen compounds of increasing sizes and complexity on the Al(111) surface. The calculations employ periodic slab models with 4 Al layers, ranging in size from (3x3) to (6x6) surface unit cells, and containing up to 144 Al atoms. Complementary quantum chemical calculations, utilizing DFT and ... |
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| Probing the Interaction of Ionic Liquids with CO2: A Raman Spectroscopy and Ab Initio Study |
05-May-2008 |
152 pages |
| Authors:
Eucker; William IV; NAVAL ACADEMY ANNAPOLIS MD
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| This research project involves an investigation of the interaction of carbon dioxide (CO2) with selected ionic liquids (ILs). Raman spectroscopy and first principle quantum mechanical calculations were performed on selected IL solvents in contact with CO2 in the effort to discover how the solvents interact with the gas. ILs are salts (mixtures of cations and anions) that are liquid at room-temperature. Recent work has shown that gas solubilities in ILs ... |
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| Synthesis and Processing of Ultra-High Temperature Metal Carbide and Metal Diboride Nanocomposite Materials |
15-Apr-2008 |
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| Authors:
Robert F Speyer; GEORGIA INST OF TECH ATLANTA SCHOOL OF MATERIALS SCIENCE AND ENGINEERING
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 | Zirconium diboride and a zirconium diboride/tantalum diboride mixture were synthesized by solution-based processing. Zirconium n-propoxide was refluxed with 2,4-pentanedione to form zirconium diketonate. This compound hydrolyzed in a controllable fashion to form a zirconia precursor. Spherical particles of 200-600 nm for pure ZrB2 and ZrB2-TaB2 mixtures were formed. Commercial powders of ZrB2 containing various concentrations of B4C, SiC, TaB2, and TaSi2 were pressureless-sintered and post-HIPed to their theoretical densities. Oxidation ... |
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| Effects of Electronic Quantum Interference, Photonic-Crystal Cavity, Longitudinal Field and Surface-Plasmon- Polariton for Optical Amplification |
09-Apr-2008 |
15 pages |
| Authors:
Danhong Huang; D A Cardimona; Paul M Alsing; AIR FORCE RESEARCH LAB KIRTLAND AFB NM SPACE VEHICLES DIRECTORATE
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| Some possibilities for coherent optical amplification of a normally-incident and weak radiation field are reviewed based on various physical mechanisms, such as electronic quantum interference induced by a coupling laser field in a three-level system, field enhancement through the cavity confinement of a radiation field in a photonic crystal and field concentration seen in a transmitted near field through a metallic surface grating due to excitation of surface-plasmon-polariton modes. Numerical ... |
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| Symposium U: Thermoelectric Power Generation. Held in Boston, Massachusetts on November 26-29, 2007 |
01-Apr-2008 |
29 pages |
| Authors:
Ryoji Funahashi; Jihui Yang; Timothy P Hogan; Terry M Tritt; MATERIALS RESEARCH SOCIETY WARRENDALE PA
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| Symposium U brought together scientists and engineers working on high efficiency thermal to electric energy conversion technologies to discuss the most recent progress in materials, current theoretical and experimental trends, characterization, and device fabrication. The symposium was designed to emphasize the multi-disciplinary nature (materials science, physics, chemistry and engineering) of the research needed to advance the state-of-the-art technology. Over 175 abstracts were received. This was more than any of the ... |
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| Natural Attenuation of Perchlorate in Groundwater: Processes, Tools and Monitoring Techniques |
01-Apr-2008 |
81 pages |
| Authors:
Robert C Borden; M T Lieberman; SOLUTIONS INDUSTRIAL AND ENVIRONMENTAL SERVICES RALEIGH NC
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| The purpose of this document is to provide users with information on 1) fate, transport and transformation of perchlorate in different geochemical environments; 2) emerging and/or specialized technologies for evaluating perchlorate attenuation in groundwater; and 3) a tiered approach for evaluating the MNA of perchlorate. This protocol does not provide a step-by-step guide to MNA of perchlorate. Instead, it presents several procedures to aid the user in determining if natural ... |
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Inorganic Chemistry
