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in creator/contributor: "Chen, S."

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Experimental and theoretical investigation of high gradient acceleration

This report contains a technical progress summary of the research conducted under the auspices of DOE Grant No. DE-FG0291ER-40648. Experimental and Theoretical Investigations of High Gradient Acceleration.'' This grant supports three research tasks: Task A consists of the design and fabrication of a 17GHz of photocathode gun, Task B supports the testing of high gradient acceleration using a 33GHz structure, and Task C comprises theoretical investigations, both in support of the experimental tas… more

Date: February 1, 1992

Creator: Bekefi, G.; Chen, C.; Chen, S.; Danly, B.; Temkin, R.J. & Wurtele, J.S.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

A brief description of lattice gas models for multiphase flows and magnetohydrodynamics

Lattice gas models for multiphase fluids and for magnetohydrodynamic fluids are briefly described. 16 refs.

Date: January 1, 1989

Creator: Chen, H.; Chen, S.; Doolen, G. D.; Matthaeus, W. H. (Los Alamos National Lab., NM (USA) & Bartol Research Foundation of the Franklin Inst., Newark, DE (USA))

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Computational Science Research in Support of Petascale Electromagnetic Modeling

Computational science research components were vital parts of the SciDAC-1 accelerator project and are continuing to play a critical role in newly-funded SciDAC-2 accelerator project, the Community Petascale Project for Accelerator Science and Simulation (ComPASS). Recent advances and achievements in the area of computational science research in support of petascale electromagnetic modeling for accelerator design analysis are presented, which include shape determination of superconducting RF ca… more

Date: June 20, 2008

Creator: Lee, L.; Akcelik, V.; Ge, L.; Chen, S.; Schussman, G.; Candel, A. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Laser heating of solid matter by light pressure-driven shocks

Heating by irradiation of a solid surface in vacuum with 5 x 10{sup 20} W cm{sup -2}, 0.8 ps, 1.05 {micro}m wavelength laser light is studied by x-ray spectroscopy of the K-shell emission from thin layers of Ni, Mo and V. A surface layer is heated to {approx} 5 keV with an axial temperature gradient of 0.6 {micro}m scale length. Images of Ni Ly{sub {alpha}} show the hot region has a {approx} 25 {micro}m diameter, much smaller than {approx} 70 {micro}m region of K{sub {alpha}} emission. 2D parti… more

Date: May 4, 2007

Creator: Akli, K.; Hansen, S. B.; Kemp, A. J.; Freeman, R. R.; Beg, F. N.; Clark, D. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Study of the k+ to pi+, neutrino, anti-neutrino decay in the momentum region p(pi+) < 199 MeV/C

Experiment E949 at Brookhaven National Laboratory has observed three candidate events for the decay K{sup +} {yields} {pi}{sup +}{nu}{bar {nu}} in the pion momentum region 140 < P{sub {pi}} < 199 MeV/c in a exposure of 1.71 x 10{sup 12} stopped kaons with an estimated total background of 0.93 {+-} 0.17(stat.){sub -0.24}{sup +0.32}(syst.) events. Combination of this observation with previous results, assuming a pion spectrum as predicted by the standard model, produces a branching fraction… more

Date: January 1, 2009

Creator: Artamonov, A. V.; Bassalleck, B.; Bhuyan, B.; Blackmore, E. W.; Bryman, D. A.; Chen, S. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Nail-like targets for laser plasma interaction experiments

The interaction of ultra-high power picosecond laser pulses with solid targets is of interest both for benchmarking the results of hybrid particle in cell (PIC) codes and also for applications to re-entrant cone guided fast ignition. We describe the construction of novel targets in which copper/titanium wires are formed into 'nail-like' objects by a process of melting and micromachining, so that energy can be reliably coupled to a 24 {micro}m diameter wire. An extreme-ultraviolet image of the i… more

Date: December 18, 2007

Creator: Pasley, J.; Wei, M.; Shipton, E.; Chen, S.; Ma, T.; Beg, F. N. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Lattice gas simulations of one and two-phase fluid flows using the Connection Machine-2

In this paper, we report recent lattice gas simulations for single-phase and two-phase flows for two dimensional problems using the Connection Machine-2. For the single-phase fluid problem, we use the standard 7-bit lattice gas model with the maximum collision rules. The velocity and vorticity field of the Kelvin-Helmholtz instability is studied. It is shown that the lattice gas method preserves the main properties of the flow patterns observed in other numerical simulations. Using colored part… more

Date: 1990-09~

Creator: Chen, S.; Doolen, G. D.; Eggert, K.; Grunau, D. & Loh, E. Y., Jr.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Proposal of a beam study in the AGS Booster

IN order to achieve the design luminosity, the Superconducting Super Collider (SSC) parameter choices emphasize the preservation of the transverse emittance requiring in the collider a normalized transverse emittance of 1 {pi}.mm.mrad. A stringent accelerator chain emittance budget must be maintained to achieve the final value. Budgeted emittance specifications for the Low Energy Booster (LEB) include 0.4 {pi}.mm.mrad at injection and {le} 0.6 {pi}.mm.mrad at extraction. The space-charge tune s… more

Date: October 1, 1991

Creator: Machida, S. & Chen, S.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Computer simulation of the martensite transformation in a model two-dimensional body

An analytical model of a martensitic transformation in an idealized body is constructed and used to carry out a computer simulation of the transformation in a pseudo-two-dimensional crystal. The reaction is assumed to proceed through the sequential transformation of elementary volumes (elementary martensitic particles, EMP) via the Bain strain. The elastic interaction between these volumes is computed and the transformation path chosen so as to minimize the total free energy. The model transfor… more

Date: May 1, 1979

Creator: Chen, S.; Khachaturyan, A.G. & Morris, J.W. Jr.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Tune shift effect due to the multipole longitudinal periodic structure in the superconducting dipole magnets

Neglecting the curvature terms, the magnetic field and the vector potential which generate the multipole longitudinal periodic structure in a superconducting dipole magnet are found. Using this field and the standard Hamiltonian perturbation theory, the tune shifts due to this periodic pattern in the superconducting dipole magnets are estimated for the Superconducting Super Collider (SSC) machine. The results suggest that this tune shift is very small for most of the multipoles and could be ign… more

Date: October 1, 1991

Creator: Lopez, G. & Chen, S.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Computer simulation of the martensite transformation in a model two-dimensional body

Date: June 1, 1979

Creator: Chen, S.; Khachaturyan, A.G. & Morris, J.W. Jr.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Lattice gas automata for flow and transport in geochemical systems

Lattice gas automata models are described, which couple solute transport with chemical reactions at mineral surfaces within pore networks. Diffusion in a box calculations are illustrated, which compare directly with Fickian diffusion. Chemical reactions at solid surfaces, including precipitation/dissolution, sorption, and catalytic reaction, can be examined with the model because hydrodynamic transport, solute diffusion and mineral surface processes are all treated explicitly. The simplicity an… more

Date: January 1, 1992

Creator: Janecky, D.R.; Chen, S.; Dawson, S.; Eggert, K.C. & Travis, B.J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Computer simulation of the formation of tweed and modulated structures in decomposition reactions

A model of coarsening in a heterogeneous cubic alloy with cubic or tetragonal precipitates is proposed. According to the model the coarsening is controlled by the relaxation of the elastic strain energy. The computer simulation of coarsening demonstrates good agreement with electron microscopic observation of the structure and diffraction pattern.

Date: March 1, 1979

Creator: Chen, S.; Morris, J.W. Jr. & Khachaturyan, A.G.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Experimental and theoretical investigation of high gradient acceleration. Progress report, June 1, 1991--February 1, 1992

This report contains a technical progress summary of the research conducted under the auspices of DOE Grant No. DE-FG0291ER-40648. ``Experimental and Theoretical Investigations of High Gradient Acceleration.`` This grant supports three research tasks: Task A consists of the design and fabrication of a 17GHz of photocathode gun, Task B supports the testing of high gradient acceleration using a 33GHz structure, and Task C comprises theoretical investigations, both in support of the experimental t… more

Date: February 1, 1992

Creator: Bekefi, G.; Chen, C.; Chen, S.; Danly, B.; Temkin, R. J. & Wurtele, J. S.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Lattice gas automata for flow and transport in geochemical systems

Date: May 1, 1992

Creator: Janecky, D. R.; Chen, S.; Dawson, S.; Eggert, K. C. & Travis, B. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Simulation studies of the transverse dipole mode multibunch instability for the SSC Collider

A computer program that assumes a point-like structure of the bunches, called TADIMMI, has been devised to study the dipole mode multibunch instability in the Superconducting Super Collider (SSC) Collider ring due to a single Positron-Electron Project (PEP) test rf cavity and the resistive wall. For the rf cavity, the following cases are considered: symmetric filling, where good agreement is obtained with ZAP code; nonsymmetric filling; elimination of the most dangerous mode of the cavity; De-Q… more

Date: January 1, 1993

Creator: Chen, S. & Lopez, G.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Flow-induced vibrations of circular cylindrical structures. [LMFBR]

The problems of flow-induced vibrations of circular cylindrical structures are reviewed. First, the general method of analysis and classification of structural responses are presented. Then, the presentation is broken up along the lines with stationary fluid, parallel flow, and cross flow. Finally, design considerations and future research needs are pointed out. 234 references.

Date: June 1, 1977

Creator: Chen, S.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

An imaging proton spectrometer for short-pulse laser plasma experiments

Ultra intense short pulse laser pulses incident on solid targets can generate energetic protons. In additions to their potentially important applications such as in cancer treatments and proton fast ignition, these protons are essential to understand the complex physics of intense laser plasma interaction. To better characterize these laser-produced protons, we designed and constructed a novel, spatially imaging proton spectrometer that will not only measure proton energy distribution with high… more

Date: May 11, 2010

Creator: Chen, H.; Hazi, A.; van Maren, R.; Chen, S.; Fuchs, J.; Gauthier, M. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Effect of fluid viscosity on coupled tube/fluid vibrations

In many reactor system components, in order to accommodate thermal expansion and to facilitate assembly, very frequently there exist small gaps among various structural and mechanical components. The gaps are usually containing flowing viscous fluid to maintain temperature in a specific range. The fluid in the gap will affect the component dynamic characteristics. Two coaxial tubes separated by a viscous fluid are studied theoretically. The fluid forces acting on the tubes associated with small… more

Date: April 1, 1977

Creator: Yeh, T. & Chen, S.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Study of the decay K+ ---> pi+ nu anti-nu in the momentum region 140 < P(pi) < 199-MeV/c

No Description Available.

Date: March 1, 2009

Creator: Artamonov, A. V.; /Serpukhov, IHEP; Bassalleck, B.; U., /New Mexico; Bhuyan, B.; /Brookhaven et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Ordered bcc phases in a Cu-Pd-Mg hydrogen separation membrane alloy

No Description Available.

Date: January 1, 2012

Creator: Dogan, O. N.; Hu, R.; Song, X.; Chen, S. & Gao, M. C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

State of the Art in EM Field Computation

This paper presents the advances in electromagnetic (EM) field computation that have been enabled by the US DOE SciDAC Accelerator Science and Technology project which supports the development and application of a suite of electromagnetic codes based on the higher-order finite element method. Implemented on distributed memory supercomputers, this state of the art simulation capability has produced results which are of great interest to accelerator designers and with realism previously not possi… more

Date: September 25, 2006

Creator: Ng, C.; Akcelik, V.; Candel, A.; Chen, S.; Folwell, N.; Ge, L. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

NMR Studies of Molecular Hydrogen in Hydrogenated Amorphous Silicon

Using NMR, the concentrations of molecular hydrogen have been measured directly in hydrogenated amorphous silicon made by the hot wire chemical vapor deposition (HWCVD) technique.

Date: January 1, 2000

Creator: Su, T.; Chen, S.; Taylor, P. C.; Crandall, R. S. & Mahan, A. H.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Studies of electron and proton isochoric heating for fast ignition

Isochoric heating of inertially confined fusion plasmas by laser driven MeV electrons or protons is an area of great topical interest in the inertial confinement fusion community, particularly with respect to the fast ignition (FI) proposal to use this technique to initiate burn in a fusion capsule. Experiments designed to investigate electron isochoric heating have measured heating in two limiting cases of interest to fast ignition, small planar foils and hollow cones. Data from Cu K{alpha} fl… more

Date: October 2, 2006

Creator: Mackinnon, A.; Key, M.; Akli, K.; Beg, F.; Clarke, R.; Clarke, D. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department