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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.
Partner: UNT Libraries Government Documents Department
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.
Partner: UNT Libraries Government Documents Department
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
Partner: UNT Libraries Government Documents Department
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.
Partner: UNT Libraries Government Documents Department
open access

2\beta + \gamma from B^0 to D^\mp K^0 \pi^\pm Decays at BaBar: aSimulation Study

Description: The authors present the results of a simulation study to perform the extraction of 2{beta} + {gamma} from B{sup 0} {yields} D{sup {-+}}K{sup 0}{pi}{sup {+-}} decays through a time-dependent Dalitz analysis of BaBar data.
Date: April 16, 2007
Creator: Polci, Francesco; Schune, Marie-Helene; Stocchi, Achille & /Orsay, LAL
Partner: UNT Libraries Government Documents Department
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.
Partner: UNT Libraries Government Documents Department
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.
Partner: UNT Libraries Government Documents Department
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.
Partner: UNT Libraries Government Documents Department
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
Partner: UNT Libraries Government Documents Department
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.
Partner: UNT Libraries Government Documents Department
open access

[3 Letters from Donald J. Maison]

Description: Copies of three letters from Donald J. Maison: a carbon copy of a letter from Maison to Chief Prosecutor (dated April 16, 1980), copy of a letter from Maison to Steve Tokoley (dated April 7, 1980), and carbon copy of letter from Maison to Bill Arnold (dated March 26, 1980).
Date: April 16, 1980
Creator: Maison, Donald J.
Partner: UNT Libraries Special Collections

[3 Levels of Interactions presentation at APAEC 2011]

Description: Photograph of a presentation "3 Levels of Interactions" at APAEC 2011, held by UNT Special Collections. The image shows a room filled with people sitting down, a presenter can be seen at the front of the room near the top right. On the top left a projector screen can be seen, with it containing a chart titled "3 Levels of Interactions" with two columns following it. APAEC stands for Asian Pacific American Empowerment Conference, an annual conference that happens every year at UNT.
Date: April 20, 2011
Partner: UNT Libraries Special Collections
open access

4-Coumarate 3-hydroxylase in the lignin biosynthesis pathway is a cytosolic ascorbate peroxidase

Description: Article describes an enzyme catalyzing the direct 3-hydroxylation of 4-coumarate to caffeate in lignin biosynthesis as a bifunctional peroxidase that oxidizes both ascorbate and 4-coumarate at comparable rates.
Date: April 30, 2019
Creator: Barros, Jaime; Escamilla-Treviño, Luis; Song, Luhua; Rao, Xiaolan; Serrani-Yarce, Juan Carlos; Palacios, Maite Docampo et al.
Partner: UNT College of Science
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
Partner: UNT Libraries Government Documents Department
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.
Partner: UNT Libraries Government Documents Department

[6 O'Clock channel 5 news team]

Description: Photograph of the 6 O'Clock channel 5 news team. From left to right: Boyd Matson, Chip Moody, Ward Andrews, Russ Bloxom and Harold Taft. The newsmen can be seen in front of a blue wall. All of the men can be seen wearing suits and ties. Chip Moody and Ward Andrews can be seen wearing black suits, while Russ Bloxom wears a gray suit and Harold Taft wears a plaid one. Boyd Matson can be seen on the left hand side wearing a white suit. Matson and Taft sit behind desks with the Channel 5 logo on the front. Moody and Bloxom sit in chairs with Andrews standing above them.
Date: April 1, 1974
Creator: WBAP-TV (Television station : Fort Worth, Tex.)
Partner: UNT Libraries Special Collections

[6 O'Clock channel 5 news team, 2]

Description: Photograph of the 6 O'Clock channel 5 news team. From left to right: Boyd Matson, Chip Moody, Ward Andrews, Russ Bloxom and Harold Taft. The newsmen can be seen in front of a blue wall. All of the men can be seen wearing suits and ties. Chip Moody and Ward Andrews can be seen wearing black suits, while Russ Bloxom wears a gray suit and Harold Taft wears a plaid one. Boyd Matson can be seen on the left hand side wearing a white suit. Matson and Taft sit behind desks with the Channel 5 logo on the front. Moody and Bloxom sit in chairs with Andrews standing above them.
Date: April 1, 1974
Creator: WBAP-TV (Television station : Fort Worth, Tex.)
Partner: UNT Libraries Special Collections

[6 O'Clock channel 5 news team, 3]

Description: Photograph of the 6 O'Clock channel 5 news team. From left to right: Boyd Matson, Chip Moody, Ward Andrews, Russ Bloxom and Harold Taft. The newsmen can be seen in front of a blue wall. All of the men can be seen wearing suits and ties. Chip Moody and Ward Andrews can be seen wearing black suits, while Russ Bloxom wears a gray suit and Harold Taft wears a plaid one. Boyd Matson can be seen on the left hand side wearing a white suit. Matson and Taft sit behind desks with the Channel 5 logo on the front. Moody and Bloxom sit in chairs with Andrews standing above them.
Date: April 1, 1974
Creator: WBAP-TV (Television station : Fort Worth, Tex.)
Partner: UNT Libraries Special Collections

[6 O'Clock Channel 5 news team, 4]

Description: Photograph of the 6 O'Clock channel 5 news team. From left to right: Boyd Matson, Chip Moody, Ward Andrews, Russ Bloxom and Harold Taft. The newsmen can be seen in front of a blue wall. All of the men can be seen wearing suits and ties. Chip Moody and Ward Andrews can be seen wearing black suits, while Russ Bloxom wears a gray suit and Harold Taft wears a plaid one. Boyd Matson can be seen on the left hand side wearing a white suit. Matson and Taft sit behind desks with the Channel 5 logo on the front. Moody and Bloxom sit in chairs with Andrews standing above them.
Date: April 1, 1974
Creator: WBAP-TV (Television station : Fort Worth, Tex.)
Partner: UNT Libraries Special Collections

[6 O'Clock Channel 5 news team, 5]

Description: Photograph of the 6 O'Clock channel 5 news team. From left to right: Boyd Matson, Chip Moody, Ward Andrews, Russ Bloxom and Harold Taft. The newsmen can be seen in front of a blue wall. All of the men can be seen wearing suits and ties. Chip Moody and Ward Andrews can be seen wearing black suits, while Russ Bloxom wears a gray suit and Harold Taft wears a plaid one. Boyd Matson can be seen on the left hand side wearing a white suit. Matson and Taft sit behind desks with the Channel 5 logo on the front. Moody and Bloxom sit in chairs with Andrews standing above them.
Date: April 1, 1974
Creator: WBAP-TV (Television station : Fort Worth, Tex.)
Partner: UNT Libraries Special Collections
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