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0.5 μm E/D AlGaAs/GaAs heterostructure field effect transistor technology with DFET threshold adjust implant

Description: A doped-channel heterostructure field effect transistor (H-FET) technology has been developed with self-aligned refractory gate processing and using both enhancement- and depletion-mode transistors. D-HFET devices are obtained with a threshold voltage adjust implant into material designed for E-HFET operation. Both E- and D-HFETs utilize W/WSi bilayer gates, sidewall spacers, and rapid thermal annealing for controlling short channel effects. The 0.5 {mu}m E- HFETs (D-HFETs) have been demonstrated with transconductance of 425 mS/mm (265-310 mS/mm) and f{sub t} of 45-50 GHz. Ring oscillator gate delays of 19 ps with a power of 0.6 mW have been demonstrated using direct coupled FET logic. These results are comparable to previous doped-channel HFET devices and circuits fabricated by selective reactive ion etching rather than ion implantation for threshold voltage adjustment.
Date: April 1997
Creator: Baca, A. G.; Sherwin, M. E.; Zolper, J. C.; Shul, R. J.; Briggs, R. D.; Heise, J. A. et al.
open access

A 1.8 K test facility for superconducting RF cavities

Description: To demonstrate the feasibility of superconducting RF technology for a high energy e{sup +}/e{sup {minus}} collider, a research and development program has begun with collaborators from Europe, Asia, and North America. The immediate goal of the R&D program is to build and operate a 50 meter-long linac at DESY with 1.3 GHz superconducting RF cavities at a temperature of 1.8 K - 2.0 K and an accelerating gradient of 15 MV/meter. The refrigeration for the test system at DESY initially will have a capacity of about 100 W at 1.8 K, distributed among three test cryostats. In a second step, refrigeration will be upgraded to 200 W at 1.8 K in order to supply the 50 meter test linac. This paper describes the cryogenics of this test system.
Date: April 1, 1994
Creator: Horlitz, G.; Knopf, U.; Lange, R.; Petersen, B.; Sellmann, D.; Trines, D. et al.
open access

A 1-Joule laser for a 16-fiber injection system

Description: A 1-J laser was designed to launch light down 16, multi-mode fibers (400-{micro}m-core dia.). A diffractive-optic splitter was designed in collaboration with Digital Optics Corporation (DOC), and was delivered by DOC. Using this splitter, the energy injected into each fiber varied <1%. The spatial profile out of each fiber was such that there were no ''hot spots,'' a flyer could successfully be launched and a PETN pellet could be initiated. Preliminary designs of the system were driven by system efficiency where a pristine TEM{sub 00} laser beam would be required. The laser is a master oscillator, power amplifier (MOPA) consisting of a 4-mm-dia. Nd:YLF rod in the stable, q-switched oscillator and a 9.5-mm-dia. Nd:YLF rod in the double-passed amplifier. Using a TEM{sub 00} oscillator beam resulted in excellent transmission efficiencies through the fibers at lower energies but proved to be quite unreliable at higher energies, causing premature fiber damage, flyer plate rupture, stimulated Raman scattering (SRS), and stimulated Brillouin scattering (SBS). Upon further investigation, it was found that both temporal and spatial beam formatting of the laser were required to successfully initiate the PETN. Results from the single-mode experiments, including fiber damage, SRS and SBS losses, will be presented. In addition, results showing the improvement that can be obtained by proper laser beam formatting will also be presented.
Date: April 6, 2004
Creator: Honig, J
open access

1+ -n+ ECR Ion Source Development Test Stand

Description: A test stand for the investigation of 1+-n+ charge boosting using an ECR ion sources is currently being assembled at the Texas A&M Cyclotron Institute. The ultimate goal is to relate the charge-boosting of ions of stable species to possible charge-boosting of ions of radioactive species extracted from the diverse, low-charge-state ion sources developed for radioactive ion beams.
Date: April 7, 2006
Creator: May, Donald P.
open access

2-D and 3-D Elastic Modeling with Shared Seismic Models

Description: Several elastic models, both 2-D and 3-D, are being built for use in calculating synthetic elastic seismic data. The models will be made available to the research community, along with the synthetic data that are being calculated from them. These shared models have been proposed or contributed by participants in a collaborative industry, national laboratory, and university research project. The purpose of the modeling is to provide synthetic data to better understand elastic wave propagation and the effects of structural and stratigraphic complexities. The 2-D models are easier to design and change and synthetic calculations can be run relatively quickly in them. It will be possible to alter their layer properties and calculate time-lapse data sets from them. Field data will be available to accompany many of the 2-D models. 3-D models are more realistic, but more difficult to design and change. They also require considerably more computing resources to calculate synthetic data from them. A new 3-D model is being designed, and will be used for computing synthetic elastic data.
Date: April 30, 2002
Creator: House, L.; Marfurt, K. J.; Larsen, S. & Martin, G. S.
open access

A 3-Axis Force Balanced Accelerometer Using a Single Proof-Mass

Description: This paper presents a new method for wideband force balancing a proof-mass in multiple axes simultaneously. Capacitive position sense and force feedback are accomplished using the same air-gap capacitors through time multiplexing. Proof of concept is experimentally demonstrated with a single-mass monolithic surface micromachined 3-axis accelerometer.
Date: April 1997
Creator: Lemkin, M.A.; Boser, B.E.; Auslander, D. & Smith, J.
open access

A 3-D Model of Signaling and Transport Pathways in Epithelial Cells

Description: A 3-dimensional computer model was developed to simulate the spatial and chemical evolution of calcium ions inside an array of human epithelial kidney cells. This is a prototype model, intended to develop a methodology to incorporate much more complex interactions of metabolic and other processes within many types of cells and lead to increased ability to predict cellular responses to disease as well as to chemical and biological warfare situations. Preliminary tests of the model are described.
Date: April 1, 2005
Creator: Quong, Andrew A. & Westbrook, Charles K.
open access

A 3-Dimensional discrete fracture network generator to examine fracture-matrix interaction using TOUGH2

Description: Water fluxes in unsaturated, fractured rock involve the physical processes occurring at fracture-matrix interfaces within fracture networks. Modeling these water fluxes using a discrete fracture network model is a complicated effort. Existing preprocessors for TOUGH2 are not suitable to generate grids for fracture networks with various orientations and inclinations. There are several 3-D discrete-fracture-network simulators for flow and transport, but most of them do not capture fracture-matrix interaction. We have developed a new 3-D discrete-fracture-network mesh generator, FRACMESH, to provide TOUGH2 with information about the fracture network configuration and fracture-matrix interactions. FRACMESH transforms a discrete fracture network into a 3 dimensional uniform mesh, in which fractures are considered as elements with unique rock material properties and connected to surrounding matrix elements. Using FRACMESH, individual fractures may have uniform or random aperture distributions to consider heterogeneity. Fracture element volumes and interfacial areas are calculated from fracture geometry within individual elements. By using FRACMESH and TOUGH2, fractures with various inclinations and orientations, and fracture-matrix interaction, can be incorporated. In this paper, results of flow and transport simulations in a fractured rock block utilizing FRACMESH are presented.
Date: April 9, 2003
Creator: Ito, Kazumasa & Yongkoo, Seol
open access

3-dimensional wells and tunnels for finite element grids

Description: Modeling fluid, vapor, and air injection and extraction from wells poses a number of problems. The length scale of well bores is centimeters, the region of high pressure gradient may be tens of meters and the reservoir may be tens of kilometers. Furthermore, accurate representation of the path of a deviated well can be difficult. Incorporating the physics of injection and extraction can be made easier and more accurate with automated grid generation tools that incorporate wells as part of a background mesh that represents the reservoir. GEOMESH is a modeling tool developed for automating finite element grid generation. This tool maintains the geometric integrity of the geologic framework and produces optimal (Delaunay) tetrahedral grids. GEOMESH creates a 3D well as hexagonal segments formed along the path of the well. This well structure is tetrahedralized into a Delaunay mesh and then embedded into a background mesh. The well structure can be radially or vertically refined and each well layer is assigned a material property or can take on the material properties of the surrounding stratigraphy. The resulting embedded well can then be used by unstructured finite element models for gas and fluid flow in the vicinity of wells or tunnels. This 3D well representation allows the study of the free- surface of the well and surrounding stratigraphy. It reduces possible grid orientation effects, and allows better correlation between well sample data and the geologic model. The well grids also allow improved visualization for well and tunnel model analysis. 3D observation of the grids helps qualitative interpretation and can reveal features not apparent in fewer dimensions.
Date: April 1, 1996
Creator: Cherry, T.A.; Gable, C.W. & Trease, H.
open access

4. International reservoir characterization technical conference

Description: This volume contains the Proceedings of the Fourth International Reservoir Characterization Technical Conference held March 2-4, 1997 in Houston, Texas. The theme for the conference was Advances in Reservoir Characterization for Effective Reservoir Management. On March 2, 1997, the DOE Class Workshop kicked off with tutorials by Dr. Steve Begg (BP Exploration) and Dr. Ganesh Thakur (Chevron). Tutorial presentations are not included in these Proceedings but may be available from the authors. The conference consisted of the following topics: data acquisition; reservoir modeling; scaling reservoir properties; and managing uncertainty. Selected papers have been processed separately for inclusion in the Energy Science and Technology database.
Date: April 1997
open access

A 5-cm dipole for the SSC-DE-1

Description: A 5cm SSC superconducting dipole that develops 6.6 tesla at 5790 A is proposed. The two layer magnet has 12% more transfer function than the present design as a result of using thin collars and close in'' iron. The thin collars provide precise positioning of the coils; they also provide minimum prestress (perhaps 2000 psi) as aid for magnet assembly. A welded skin around the iron provides the final prestress and shapes and the coil geometry. A prestressed aluminum bar placed between the vertically split iron yokes provides precise control of the gap between yokes halves and is designed to allow gap to close tightly during cooldown so that there is no decrease of prestress. In order to reduce the effect of iron saturation on the field multipoles the iron ID has been optimized to an elliptical shape. The coil inner layer is a 30 strand cable with 1.3:1 cu/sc. The outer layer is a 36 strand cable wit 1.8:1 cu/sc. At the operating field of 6.6 tesla the current density in the copper is 666 A/mm{sup 2} and 760 A/mm{sup 2} in the inner and outer layers respectively. The magnet short sample performance is limited by the inner layer. Operating at 4.35 K the maximum current and central field are 6896 A and 7.95 tesla. The calculated operating short sample temperature at 6.6 tesla and 5798 A is 5.17 K (0.82 K temperature margin). The magnet stored energy is 100.0 (KJ/m) at the 5790 A operating current. A mechanically similar 5cm bore two layer dipole for the cable test facility (D-16B-1) has been recently built and tested. The magnet had no collars and the iron was placed directly on the coil OD. The magnet's first quench was at 7 tesla with 6000 A and it reached 7.6 tesla at …
Date: April 30, 1990
Creator: Caspi, S.
open access

7-GeV Advanced Photon Source Conceptual Design Report

Description: During the past decade, synchrotron radiation emitted by circulating electron beams has come into wide use as a powerful, versatile source of x-rays for probing the structure of matter and for studying various physical processes. Several synchrotron radiation facilities with different designs and characteristics are now in regular operation throughout the world, with recent additions in this country being the 0.8-GeV and 2.5-GeV rings of NSLS at Brookhaven National Laboratory. However, none of the operating facilities has been designed to use a low-emittance, high-energy stored beam, together with modern undulator devices, to produce a large number of hard x-ray beams of extremely high brilliance. This document is a proposal to the Department of Energy to construct and operate high-energy synchrotron radiation facility at Argonne National Laboratory. We have now chosen to set the design energy of this facility at 7.0 GeV, with the capability to operate at up to 7.5 GeV.
Date: April 1, 1987
open access

7-GeV Advanced Photon Source : Conceptual Design Report

Description: During the past decade, synchrotron radiation emitted by circulating electron beams has come into wide use as a powerful, versatile source of x-rays for probing the structure of matter and for studying various physical processes. Several synchrotron radiation facilities with different designs and characteristics are now in regular operation throughout the world, with recent additions in this country being the 0.8-GeV and 2.5-GeV rings of NSLS at Brookhaven National Laboratory. However, none of the operating facilities has been designed to use a low-emittance, high-energy stored beam, together with modern undulator devices, to produce a large number of hard x-ray beams of extremely high brilliance. This document is a proposal to the Department of Energy to construct and operate high-energy synchrotron radiation facility at Argonne National Laboratory. We have now chosen to set the design energy of this facility at 7.0 GeV, with the capability to operate at up to 7.5 GeV.
Date: April 1987
Creator: Argonne National Laboratory
open access

8-oxoguainine enhances bending of DNA that favors binding of glycosylases

Description: Molecular dynamics (MD) simulations were carried out on the DNA oligonucleotide GGGAACAACTAG:CTAGTTGTTCCC in its native form and with guanine in the central G19:C6 base pair replaced by 8-oxoguanine (8oxoG). A box of explicit water molecules was used for solvation and Na+ counterions were added to neutralize the system. The direction and magnitude of global bending were assessed by a technique used previously to analyze simulations of DNA containing a thymine dimer. The presence of 8oxoG did not greatly affect the magnitude of DNA bending; however, bending into the major groove was significantly more probable when 8oxoG replaced G19. Crystal structures of glycosylases bound to damaged-DNA substrates consistently show a sharp bend into the major groove at the damage site. We conclude that changes in bending dynamics that assist the formation of this kink are a part of the mechanism by which glycosylases of the base excision repair pathway recognize the presence of 8oxoG in DNA.
Date: April 23, 2003
Creator: Miller, John H.
captions transcript

9-11 Commission Hearing #1, April 1, 2003, Part 1

Description: Recording of the first public hearing held by the National Commission on Terrorist Attacks upon the United States on April 1, 2003 at the Alexander Hamilton U.S. Custom House. This hearing specifically addresses the topics of borders, money, and transportation; law enforcement, domestic intelligence, and homeland security; and immediate response to the attacks. This section includes testimony on the topic of borders, money, and transportation security from representatives of the U.S. Department of Justice, Boies, Schiller, & Flexner LLP, and the U.S. General Accounting Office. It also includes a question and answer session.
Date: April 1, 2003
Duration: 1 hour 2 minutes 31 seconds
Creator: National Commission on Terrorist Attacks upon the United States
captions transcript

9-11 Commission Hearing #1, April 1, 2003, Part 2

Description: Recording of the first public hearing held by the National Commission on Terrorist Attacks upon the United States on April 1, 2003 at the Alexander Hamilton U.S. Custom House in New York City. This hearing specifically addresses the topics of borders, money, and transportation; law enforcement, domestic intelligence, and homeland security; and immediate response to the attacks. This section includes testimony from Steven Brill on the subject of law enforcement, domestic intelligence, and homeland security.
Date: April 1, 2004
Duration: 42 minutes 26 seconds
Creator: National Commission on Terrorist Attacks upon the United States
captions transcript

9-11 Commission Hearing #1, April 1, 2003, Part 3

Description: Recording of the first public hearing held by the National Commission on Terrorist Attacks upon the United States on April 1, 2003 at the Alexander Hamilton U.S. Custom House in New York City.This hearing specifically addresses the topics of borders, money, and transportation; law enforcement, domestic intelligence, and homeland security; and immediate response to the attacks. This section includes testimony from representatives of RAND, the Markle Foundation, and the ANSER Institute on the topic of law enforcement, domestic intelligence, and homeland security, in addition to a question and answer session.
Date: April 1, 2003
Duration: 1 hour 2 minutes 43 seconds
Creator: National Commission on Terrorist Attacks upon the United States
captions transcript

9-11 Commission Hearing #1, April 1, 2003, Part 4

Description: Recording of the first public hearing held by the National Commission on Terrorist Attacks upon the United States on April 1, 2003 at the Alexander Hamilton U.S. Custom House in New York City.This hearing specifically addresses the topics of borders, money, and transportation; law enforcement, domestic intelligence, and homeland security; and immediate response to the attacks. This section includes the question and answer session on law enforcement, domestic intelligence, and homeland security.
Date: April 1, 2003
Duration: 34 minutes 02 seconds
Creator: National Commission on Terrorist Attacks upon the United States
captions transcript

9-11 Commission Hearing #1, April 1, 2003, Part 5

Description: Recording of the first public hearing held by the National Commission on Terrorist Attacks upon the United States on April 1, 2003 at the Alexander Hamilton U.S. Custom House in New York City.This hearing specifically addresses the topics of borders, money, and transportation; law enforcement, domestic intelligence, and homeland security; and immediate response to the attacks.This section begins the testimony from representatives of the Arlington County Fire Department, the American Society of Civil Engineers, and the New York Department of Design and Construction on the topic of immediate response to the 9/11 attacks.
Date: April 1, 2003
Duration: 11 minutes 42 seconds
Creator: National Commission on Terrorist Attacks upon the United States
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