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Some recent results in Au+Au collisions at AGS

Description: Many interesting results have been obtained for Au + Au reactions at AGS. The basic information about the reaction dynamics comes from the hadronic distribution. and this article reviews the recent progress of these distributions in details. The proton rapidity distribution shows significantly increased stopping compared to lighter systems, implying the formation of a state of high baryon density. Unlike reactions at this energy induced by lighter heavy ions, at low {ital m{sub t} - m{sub 0}} t… more
Date: December 31, 1996
Creator: Chen, Z.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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An Analytical Modeling Method for Calculating the Current Delivery Capacity of a Thin-Film Cathode and the Stability of Localized Corrosion Under Atmospheric Environemnts

Description: Corrosion resistant materials under atmospheric conditions can suffer from localized corrosion (e.g., pitting, crevice, stress-corrosion cracking). The stability of such a localized corrosion site requires that the site (anode) must dissolve at a sufficiently high rate to maintain the critical chemistry and that it be coupled to a wetted surrounding area (cathode) that can provide a matching cathodic current. The objectives of this study were to computationally characterize the stability of suc… more
Date: October 11, 2006
Creator: Chen, Z.Y. & Kelly, R.G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Silicon surface and bulk defect passivation by low temperature PECVD oxides and nitrides

Description: The effectiveness of PECVD passivation of surface and bulk defects in Si, as well as phosphorous diffused emitters, Is investigated and quantified. Significant hydrogen incorporation coupled with high positive charge density in the PECVD SiN layer is found to play an important role in bulk and surface passivation. It is shown that photo-assisted anneal in a forming gas ambient after PECVD depositions significantly improves the passivation of emitter and bulk defects. PECVD passivation of phosph… more
Date: January 1, 1995
Creator: Chen, Z.; Rohatgi, A. & Ruby, D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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A particle method for history-dependent materials

Description: A broad class of engineering problems including penetration, impact and large rotations of solid bodies causes severe numerical problems. For these problems, the constitutive equations are history dependent so material points must be followed; this is difficult to implement in an Eulerian scheme. On the other hand, purely Lagrangian methods typically result in severe mesh distortion and the consequence is ill conditioning of the element stiffness matrix leading to mesh lockup or entanglement. R… more
Date: June 1, 1993
Creator: Sulsky, D.; Chen, Z. & Schreyer, H. L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Vacuum seals design and testing for a linear accelerator of the National Spallation Neutron Source

Description: Vacuum seals are very important to ensure that the Spallation Neutron Source (SNS) Linac has an optimum vacuum system. The vacuum joints between flanges must have reliable seals to minimize the leak rate and meet vacuum and electrical requirements. In addition, it is desirable to simplify the installation and thereby also simplify the maintenance required. This report summarizes an investigation of the metal vacuum seals that include the metal C-seal, Energized Spring seal, Helcoflex Copper Del… more
Date: February 1, 2000
Creator: Chen, Z.; Gautier, C.; Hemez, F. & Bultman, N. K.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Electronics cooling of Phenix multiplicity and vertex detector

Description: The Multiplicity and Vertex Detector (MVD) uses silicon strip sensors arranged in two concentric barrels around the beam pipe of the PHENIX detector that will be installed at Brookhaven National Laboratory. Each silicon sensor is connected by a flexible kapton cable to its own front-end electronics printed circuit board that is a multi-chip module or MCM. The MCMs are the main heat source in the system. To maintain the MVD at optimized operational status, the maximum temperature of the multi-ch… more
Date: August 1, 1996
Creator: Chen, Z. & Gregory, W. S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Computational modeling and analysis of a flow in a storage room

Description: When a radioactive material gas is accidentally released with a room, the present of the hazardous gas will directly affect the people safety inside. In this study, the flow field and gas dispersion in a ventilated tritium storage room at Los Alamos National Laboratory was simulated using CFX-5.5, a commercially available CFD package using a finite volume methodology. CFD models provide a simultaneously numerical solution of continuity, Navier-Stokes, and energy equations for a flow field geome… more
Date: January 1, 2002
Creator: Chen, Z. (Zukun); Konecni, S. (Snezana) & Whicker, J. J. (Jeffrey J.)
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Rapid thermal processing of high-efficiency silicon solar cells with controlled in-situ annealing

Description: Silicon solar cell efficiencies of 17.1%, 16.4%, 14.8%, and 14.9% have been achieved on FZ, Cz, multicrystalline (mc-Si), and dendritic web (DW) silicon, respectively, using simplified, cost-effective rapid thermal processing (RTP). These represent the highest reported efficiencies for solar cells processed with simultaneous front and back diffusion with no conventional high-temperature furnace steps. Appropriate diffusion temperature coupled with the added in-situ anneal resulted in suitable m… more
Date: January 1, 1995
Creator: Doshi, P.; Rohatgi, A.; Ropp, M.; Chen, Z.; Ruby, D. & Meier, D. L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Applications of a new magnetic monitoring technique to in situ evaluation of fatigue damage in ferrous components

Description: This project consisted of research into the use of magnetic inspection methods for the estimation of fatigue life of nuclear pressure vessel steel. Estimating the mechanical and magnetic properties of ferromagnetic materials are closely interrelated, therefore, measurements of magnetic properties could be used to monitor the evolution of fatigue damage in specimens subjected to cyclic loading. Results have shown that is possible to monitor the fatigue damage nondestructively by magnetic techniq… more
Date: June 1, 1994
Creator: Jiles, D. C.; Biner, S. B.; Govindaraju, M. R. & Chen, Z. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Prospects for Universal Heat Mining: from a Jules Verne vision to a 21st century reality

Description: The extraction of heat or thermal energy from the Earth -- heat mining -- has the potential to play a major role as an energy supply technology for the 21st century. However, even if reservoir stimulation goals are achieved, the role of heat mining with today's energy prices and development costs is limited to only a small fraction of the earth's surface, specifically to geologically active regions where geothermal gradients are high. This paper examines the prospects for universal heat mining … more
Date: January 20, 1994
Creator: Tester, J. W.; Herzog, H. J.; Chen, Z.; Potter, R. M. & Frank, M. G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Recent results of E866 on hadron production in Au+Au reaction at AGS energies

Description: Data of hadronic particle production in Au+Au reactions at E/A=11.6 GeV has been measured. A systematic presentation for proton spectra in central reactions is made, as well as the rapidity distributions of particle yields for pions and protons Centrality dependence of spectra for pions, protons, and deuterons is discussed. These results imply there is a large degree of stopping and a subsequent radial expansion in central Au+Au reactions. 9 refs., 4 figs.
Date: December 31, 1995
Creator: Chen, Z.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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1993 annual final progress report: July 1992 through June 1993

Description: This is the first annual report since the Inauguration of the University Center of Excellence for Photovoltaics Research and Development (UCEP) at Georgia Tech. The essential objective of the Center is to improve the fundamental understanding of the science and technology of advanced PV devices and materials, to provide training and enrich the educational experience of students in the field, and to increase US competitiveness by providing guidelines to industry and DOE for achieving cost-effect… more
Date: November 1, 1994
Creator: Rohatgi, A.; Crotty, G.; Chen, Z.; Sana, P.; Salami, J.; Doolittle, A. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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R-matrix analysis for nitrogen and oxygen

Description: As part of the Hiroshima-Nagasaki Dose Reevaluation Program, new evaluations of the neutron cross sections for {sup 14}N and {sup 16}O were made for ENDF/B-VI, based at low energies on multichannel R-matrix analyses of reactions in the {sup 15}N and {sup 17}O systems. The types of data used in the analysis, and the resulting cross sections and resonance structures are briefly described. The resonance structure in the neutron cross sections was especially well determined by including precise, hi… more
Date: February 1, 1994
Creator: Hale, G. M.; Young, P. G.; Chadwick, M. B. & Chen, Z.-P.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Survey of results from Brookhaven Experiment 802 at the AGS

Description: Brookhaven Experiment 802 (E-802) is a magnetic spectrometer experiment which is directed toward the measurement of particle momentum spectra and particle-particle correlations following reactions with 14.5 GeV/u O and Si ions. In addition to the spectrometer there are detectors to measure the transverse energy flow, longitudinal energy flow, and the multiplicity. These detectors can be used to characterize the particle spectra or correlated between themselves. Particle spectra have been obtain… more
Date: January 1, 1989
Creator: Abbott, T.; Akiba, Y.; Alburger, D.; Beavis, D.; Bloomer, M. A.; Bond, P. D. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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New evaluations of neutron cross sections for sup 14 N and sup 16 O

Description: New evaluations of the neutron cross sections for {sup 14}N and {sup 16}O have been made for ENDF/B=VI. The evaluations are based at low energies on R-matrix analyses of reactions in the {sup 15}N and {sup 17}O systems, and at higher energies on GNASH calculations and experimental data evaluations, including covariance analyses. The {sup 15}N system R-matrix analysis includes data from reactions among the channels n+{sup 14}N, p+{sup 14}C, and {alpha}+{sup 11}B at energies corresponding to exci… more
Date: January 1, 1991
Creator: Hale, G.M.; Young, P.G.; Chadwick, M. (Los Alamos National Lab., NM (USA)) & Chen, Z.P. (Qinghua Univ., Beijing, BJ (China))
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Extended emission sources observed via two-proton correlations

Description: Two-particle correlations between light particles emitted in heavy-ion reactions may be used to extract information on the spatial extent and time development of the emission source. Such measurements have provided evidence for the formation and decay of localized regions of high excitation. An interesting aspect of these measurements is the observation that the less energetic particles are emitted from sources of larger apparent dimensions. This has been interpreted as an indication that the l… more
Date: January 1, 1989
Creator: Awes, T. C.; Ferguson, R. L.; Obenshain, F. E.; Plasil, F.; Young, G. R.; Pratt, S. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Extended emission sources observed via two-proton correlations

Description: Two-proton correlations were measured as a function of the total energy and relative momentum of the proton. The correlation is analyzed for different orientations of the relative momentum, which allows information on the size and lifetime of the emission source to be extracted. The most energetic particles are emitted from a short- lived source of compound nucleus dimensions while the lower energy protons appear to be emitted from a source considerably larger than the compound nucleus. 9 refs.… more
Date: January 1, 1988
Creator: Awes, T. C.; Ferguson, R. L.; Obenshain, F. E.; Plasil, F.; Young, G. R.; Pratt, S. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Multiple Energy Computer Tomography (MECT) at the NSLS: Status report

Description: Status of the synchrotron-based computed tomography (CT) system Multiple Energy Computed Tomography (MECT) system is described. MECT, that uses monochromatic beams from the X17 superconducting wiggler beam line at the National Synchrotron Light Source (NSLS), will be used for imaging the human head and neck. An earlier prototype MECT produced images of phantoms and living rodents. This report summarizes the studies with the prototype, and describes the design, construction, and test results of … more
Date: September 1, 1994
Creator: Dilmanian, F. A.; Wu, X. Y.; Chen, Z.; Ren, B.; Slatkin, D. N.; Chapman, D. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Oblate-prolate shape competition in Z = 34 to 38 nuclei

Description: Now magic numbers for deformed shapes are established at N and Z of 38 and N of 60. These shell gaps at large deformation (..beta.. approx. = 0.4) are magic when the proton and neutron shell gaps reinforce each other. Other shell gaps for 34 and 36 are predicted to be important for oblate deformation. The competition between these oblate and the 38 prolate gaps as well as the 40 spherical shell gap are considered. In /sup 71/Se coexistence of oblate (..beta.. approx. = -0.24) and large prolate … more
Date: September 1, 1987
Creator: Hamilton, J. H.; Ramayya, A. V.; Zhao, X.; Maguire, C. F.; Ma, W. C.; KormickI, J. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Equilibria and Effect of Diluent in the Solvent Extraction of Lithium Salts by Highly Alkylated 14-Crown-4-Ethers

Description: As shown by survey experiments, 14-crown-4 ethers bearing certain aliphatic substituents exhibit strong selectivity for lithium. Both selectivity and overall extraction efficiency depend markedly on type of ring substituents and on diluent properties. To understand such effects in greater detail, extraction of LiCl by the crown ether 2,2,3,3,6,9,9,10,10-nonamethyl-14-crown-4 (NM14C4) was subjected to equilibrium analysis. By use of the program SXLSQI (a solvent-extraction modeling program), the… more
Date: December 31, 1996
Creator: Moyer, B. A.; Sachleben, R. A.; Sun, Y.; Driver, J. L.; Chen, Z.; Cavenaugh, K. L. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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