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Promising X-ray fluorescence tests for superconducting tunneljunction detector

Description: Scientists in the Physical Biosciences Division of the Ernest Orlando Berkeley National Laboratory (Berkeley Lab) studying transition metals in proteins with fluorescence-detected L-edge absorption spectroscopy have found the measurements to be extremely challenging. The difficulty is that the metal centers are present in very dilute concentrations so that their weak fluorescence is often obscured by strong background signals carbon and oxygen. To solve this problem, the Berkeley group has been… more
Date: May 15, 2001
Creator: Friedrich, Stephan & Robinson, Arthur L.
Partner: UNT Libraries Government Documents Department
open access

The Wavefront Control System for the National Ignition Facility

Description: The National Ignition Facility (NIF) requires that pulses from each of the 192 laser beams be positioned on target with an accuracy of 50 {micro}m rms. Beam quality must be sufficient to focus a total of 1.8 MJ of 0.351-{micro}m light into a 600-{micro}m-diameter volume. An optimally flat beam wavefront can achieve this pointing and focusing accuracy. The control system corrects wavefront aberrations by performing closed-loop compensation during laser alignment to correct for gas density variat… more
Date: October 15, 2001
Creator: Van Atta, L.; Perez, M.; Zacharias, R. & Rivera, W.
Partner: UNT Libraries Government Documents Department
open access

Whole genome amplification - Review of applications and advances

Description: The concept of Whole Genome Amplification is something that has arisen in the past few years as modifications to the polymerase chain reaction (PCR) have been adapted to replicate regions of genomes which are of biological interest. The applications here are many--forensics, embryonic disease diagnosis, bio terrorism genome detection, ''imoralization'' of clinical samples, microbial diversity, and genotyping. The key question is if DNA can be replicated a genome at a time without bias or non ra… more
Date: November 15, 2001
Creator: Hawkins, Trevor L.; Detter, J.C. & Richardson, Paul
Partner: UNT Libraries Government Documents Department
open access

Magnetic bead purification of labeled DNA fragments forhigh-throughput capillary electrophoresis sequencing

Description: We have developed an automated purification method for terminator sequencing products based on a magnetic bead technology. This 384-well protocol generates labeled DNA fragments that are essentially free of contaminates for less than $0.005 per reaction. In comparison to laborious ethanol precipitation protocols, this method increases the phred20 read length by forty bases with various DNA templates such as PCR fragments, Plasmids, Cosmids and RCA products. Our method eliminates centrifugation … more
Date: September 15, 2001
Creator: Elkin, Christopher; Kapur, Hitesh; Smith, Troy; Humphries, David; Pollard, Martin; Hammon, Nancy et al.
Partner: UNT Libraries Government Documents Department
open access

A molecular link between stem cell regulation and floral patterning in Arabidopsis.

Description: OAK-B135 The homeotic gene AGAMOUS (AG) has dual roles in specifying floral organ fate and limiting stem cell proliferation in Arabidopsis flowers. We show here that the floral identity protein LEAFY (LFY), a transcription factor expressed throughout the flower, acts together with the homeodomain protein WUSCHEL (WUS) to activate AG in the center of flowers. WUS was previously identified because of its role in maintaining a stem cell population in the center of both shoot and floral meristems. … more
Date: June 15, 2001
Creator: Lohmann, J. U., Hong, R. L., Hobe, M., Busch, M. A., Parcy, F., Simon, R., and Weigel, D.
Partner: UNT Libraries Government Documents Department
open access

CALORIMETRY FOR GLOBAL MEASUREMENTS IN PHENIX.

Description: The charged particle multiplicity, dN{sub ch}/d{eta}, and transverse energy, E{sub t}, are fundamental aspects of Heavy Ion collisions which PHENIX has measured in Au-Au collisions at a center-of-mass (c.m.s.) energy {radical}s{sub N}N = 130 GeV. E{sub t} is a multiparticle global observable related, through the Bjorken relation, to the maximum energy density achieved in the collision. For a given c.m.s. energy, the multiplicity and transverse energy are expected to increase with the number of … more
Date: January 15, 2001
Creator: WHITE,S.N. FOR PHENIX COLLABORATION
Partner: UNT Libraries Government Documents Department
open access

Simulating the operation of photosensor-based lighting controls

Description: Energy savings from the use of daylighting in commercial buildings are realized through implementation of photoelectric lighting controls that dim electric lights when sufficient daylight is available to provide adequate workplane illumination. The dimming level of electric lighting is based on the signal of a photosensor. Current simulation approaches for such systems are based on the questionable assumption that the signal of the photosensor is proportional to the task illuminance. This paper… more
Date: February 15, 2001
Creator: Ehrlich, Charles; Papamichael, Konstantinos; Lai, Judy & Revzan, Kenneth
Partner: UNT Libraries Government Documents Department
open access

Indirect-Drive Noncryogenic Double-Shell Ignition Targets for the National Ignition Facility: Design and Analysis

Description: The central goal of the National Ignition Facility (NIF) is demonstration of controlled thermonuclear ignition. The mainline ignition target is a low-Z, single-shell cryogenic capsule designed to have weakly nonlinear Rayleigh-Taylor growth of surface perturbations. Double-shell targets are an alternative design concept that avoids the complexity of cryogenic preparation but has greater physics uncertainties associated with performance-degrading mix. A typical double-shell design involves a hig… more
Date: October 15, 2001
Creator: Amendt, P.; Colvin, J.; Tipton, R. E.; Hinkel, D.; Edwards, M. J.; Landen, O. L. et al.
Partner: UNT Libraries Government Documents Department
open access

Structural aspects of the fivefold quasicrystalline Al-Cu-Fe surface from STM and dynamical LEED Studies

Description: We investigate the atomic structure of the fivefold surface of an icosahedral Al-Cu-Fe alloy, using scanning tunneling microscopy (STM) imaging and a special dynamical low energy-electron diffraction (LEED) method. STM indicates that the step heights adopt (primarily) two values in the ratio of tau, but the spatial distribution of these two values does not follow a Fibonacci sequence, thus breaking the ideal bulk-like quasicrystalline layer stacking order perpendicular to the surface. The appea… more
Date: April 15, 2001
Creator: Cai, T.; Shi, F.; Shen, Z.; Gierer, M.; Goldman, A. I.; Kramer, M. J. et al.
Partner: UNT Libraries Government Documents Department
open access

Nuclear Proliferation Using Laser Isotope Separation -- Verification Options

Description: Two levels of nonproliferation verification exist. Signatories of the basic agreements under the Nuclear Non-proliferation Treaty (NPT) agree to open their nuclear sites to inspection by the IAEA. A more detailed and intrusive level was developed following the determination that Iraq had begun a nuclear weapons development program that was not detected by the original level of verification methods. This level, referred to as 93+2 and detailed in model protocol INFCIRC/540, allows the IAEA to do… more
Date: October 15, 2001
Creator: Erickson, S A
Partner: UNT Libraries Government Documents Department
open access

First Results of Reaction Propagation Rates in HMX at High Pressure

Description: The authors have measured the reaction propagation rate (RPR) in weapons-grade, ultrafine octahydro-1,3,57-tetranitro-1,3,5,7-tetrazocine (HMX) powder in a diamond anvil cell over the pressure range 0.7-35 GPa. In order to have a cross-comparison of their experiments, they carried out a series of experiments on nitromethane (NM) up to 15 GPa. The results on NM are indistinguishable from previous measurements of Rice and Folz. In comparison to high-pressure, NM, the burn process for solid HMX is… more
Date: June 15, 2001
Creator: Farber, D L; Esposito, A; Zaug, J M & Aracne-Ruddle, C
Partner: UNT Libraries Government Documents Department
open access

Proposed Multiconjugate Adaptive Optics Experiment at Lick Observatory

Description: While the theory behind design of multiconjugate adaptive optics (MCAO) systems is growing, there is still a paucity of experience building and testing such instruments. We propose using the Lick adaptive optics (AO) system as a basis for demonstrating the feasibility/workability of MCAO systems, testing underlying assumptions, and experimenting with different approaches to solving MCAO system issues.
Date: August 15, 2001
Creator: Bauman, B. J.; Gavel, D. T.; Flath, L. M.; Hurd, R. L.; Max, C. E. & Olivier, S. S.
Partner: UNT Libraries Government Documents Department
open access

Summary of Synthetic Lap Polishing Experiments at LLNL, FY95

Description: The purpose of this research was to support the optics finishing development work for the NIF, the National Ignition Facility. One of the major expenses for the construction of NIF is the cost of finishing of the large aperture optics. One way to significantly reduce the cost of the project is to develop processes to reduce the amount of time necessary to polish the more than 3,000 amplifier slabs. These slabs are rectangular with an aspect ratio of more than twenty to one and are made of a ver… more
Date: October 15, 2001
Creator: Nichols, M A
Partner: UNT Libraries Government Documents Department
open access

The Overview of the National Ignition Facility Distributed Computer Control System

Description: The Integrated Computer Control System (ICCS) for the National Ignition Facility (NIF) is a layered architecture of 300 front-end processors (FEP) coordinated by supervisor subsystems including automatic beam alignment and wavefront control, laser and target diagnostics, pulse power, and shot control timed to 30 ps. FEP computers incorporate either VxWorks on PowerPC or Solaris on UltraSPARC processors that interface to over 45,000 control points attached to VME-bus or PCI-bus crates respective… more
Date: October 15, 2001
Creator: Lagin, L J; Bettenhausen, R C; Carey, R A; Estes, C M; Fisher, J M; Krammen, J E et al.
Partner: UNT Libraries Government Documents Department
open access

First Results of Reaction Propagation Rates in HMX at High Pressure

Description: The authors have measured the reaction propagation rate (RPR) in weapons-grade, ultrafine octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) powder in a diamond anvil cell over the pressure range 0.7-35 GPa. In order to have a cross-comparison of their experiments, they carried out a series of experiments on nitromethane (NM) up to 15 GPa. The results on NM are indistinguishable from previous measurements of Rice and Folz. In comparison to high-pressure NM, the burn process for solid HMX is… more
Date: June 15, 2001
Creator: Farber, D L; Esposito, A; Zaug, J M & Aracne-Ruddle, C
Partner: UNT Libraries Government Documents Department
open access

An Ultra-Compact Marx-Type High-Voltage Generator

Description: This paper discusses the design of an ultra-compact, Marx-type, high-voltage generator. This system incorporates high-performance components that are closely coupled and integrated into an extremely compact assembly. Low profile, custom ceramic capacitors with coplanar extended electrodes provide primary energy storage. Low-inductance, spark-gap switches incorporate miniature gas cavities imbedded within the central region of the annular shaped capacitors, with very thin dielectric sections sep… more
Date: June 15, 2001
Creator: Goerz, D.; Ferriera, T.; Nelson, D.; Speer, R. & Wilson, M.
Partner: UNT Libraries Government Documents Department
open access

Microsats for On-Orbit Support Missions

Description: I appreciate the opportunity to address this conference and describe some of our work and plans for future space missions and capabilities. My presentation will consist of a short overview of our program, some potential missions and enabling technologies, as well as, a description of some of our test vehicles and ongoing docking experiments. The Micro-Satellite Technology Program at Lawrence Livermore National Laboratory is developing technologies for a new generation of a very highly capable a… more
Date: March 15, 2001
Creator: Ledebuhr, A G
Partner: UNT Libraries Government Documents Department
open access

Industrial Applications of Low Temperature Plasmas

Description: The use of low temperature plasmas in industry is illustrated by the discussion of four applications, to lighting, displays, semiconductor manufacturing and pollution control. The type of plasma required for each application is described and typical materials are identified. The need to understand radical formation, ionization and metastable excitation within the discharge and the importance of surface reactions are stressed.
Date: March 15, 2001
Creator: Bardsley, J N
Partner: UNT Libraries Government Documents Department
open access

Measurement of the Polarization of the K(Beta)2 Line of Helium-like V21+

Description: We have measured the polarization of the intercombination line 1s3p {sup 3}P{sub 1}-1s{sup 2}{sup 1}S{sub 0}, the so called K{beta}2 line, in helium-like V{sup 21+} using two Bragg crystal spectrometers. The ions were excited in the Lawrence Livermore National Laboratory electron beam ion trap. We find values which are not significantly different from theoretical predictions based on some admixing of the initial state by the hyperfine interaction. In this short paper we present our results.
Date: October 15, 2001
Creator: Smith, A. J.; Beiersdorfer, P.; Wong, K. L. & Reed, K. J.
Partner: UNT Libraries Government Documents Department
open access

Operation of a Four-Cylinder 1.9L Propane Fueled HCCI Engine

Description: A four-cylinder 1.9 Volkswagen TDI Engine has been converted to run in Homogeneous Charge Compression Ignition (HCCI) mode. The stock configuration is a turbocharged direct injection Diesel engine. The combustion chamber has been modified by discarding the in-cylinder Diesel fuel injectors and replacing them with blank inserts (which contain pressure transducers). The stock pistons contain a reentrant bowl and have been retained for the tests reported here. The intake and exhaust manifolds have… more
Date: March 15, 2001
Creator: Flowers, D.; Aceves, S. M.; Martinez-Frias, J.; Smith, J. R.; Au, M.; Girard, J. et al.
Partner: UNT Libraries Government Documents Department
open access

In-Situ Observations of Phase Transformations in the HAZ of 2205 Duplex Stainless Steel Weldments

Description: Ferrite ({delta})/austenite ({gamma}) transformations in the heat affected zone (HAZ) of a gas tungsten arc (GTA) weld in 2205 duplex stainless steel are observed in real-time using spatially resolved X-ray diffraction (SRXRD) with high intensity synchrotron radiation. A map showing the locations of the {delta} and {gamma} phases with respect to the calculated weld pool dimensions has been constructed from a series of SRXRD scans. Regions of liquid, completely transformed {gamma}, a combination… more
Date: August 15, 2001
Creator: Palmer, T A; Elmer, J W & Wong, J
Partner: UNT Libraries Government Documents Department
open access

Infrared Heating of Hydrogen Layers in Hohlraums

Description: The authors report results of modeling and experiments on infrared heated deuterium-hydride (HD) layers in hohlraums. A 2 mm diameter, 40 {micro}m thick shell with 100-400 {micro}m thick HD ice inside a NIF scale-1 gold hohlraum with 1-3 {micro}m rms surface roughness is heated by pumping the HD vibrational bands. Models indicate control of the low-mode layer shape by adjusting the infrared distribution along the hohlraum walls. They have experimentally demonstrated control of the layer symmetr… more
Date: August 15, 2001
Creator: Kozioziemski, B J; McEachern, R L; London, R A & Bitter, D N
Partner: UNT Libraries Government Documents Department
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