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Diffusional creep of multicomponent systems. Progress report, February 1, 1975--January 31, 1976

Description: Hydrogen embrittlement was studied from the viewpoint of the interaction of hydrogen with the stress field of particles. The interaction between dislocation loops was studied to include shear components of the Burgers vector. It turned out that this additional component could stabilize both the cuboidal arrangement and the stair-step configuration of square dislocation loops. These results were used to explain certain precipitation morphologies. Equipment improvements are reported. The only creep results obtained so far were the temperature and stress dependences of penetration velocity on a beta-tin single crystal, and the stress dependences of lead and succinonitrile polycrystals. They agree with literature data. (DLC)
Date: January 1, 1976
Creator: Li, J.C.M.
Partner: UNT Libraries Government Documents Department

Nature of simultaneous processes in plastic deformation

Description: The nature of two simultaneous processes is analyzed in detail. It is found that the experimental activation enthalpy increases with temperature for parallel processes and decreases with temperature for consecutive processes. Similarly the activation volume increases with pressure for consecutive processes and decreases with pressure for parallel processes. The creep rate stress exponent increases with stress for parallel processes and decreases with stress for consecutive processes. Each activation parameter is the weighted average of the corresponding ones for the individual processes. Several ways are indicated for the determination of individual activation parameters. The nature of three and four simultaneous processes is discussed briefly. When several processes are operating simultaneously, one of them may be rate controlling under certain conditions. This rate-controlling process may change with deformation parameters and a transition'' can be defined. The relation between transition parameters and the construction of deformation mechenism diagrams are also discussed. (auth)
Date: January 1, 1972
Creator: Li, J.C.M.
Partner: UNT Libraries Government Documents Department

Diffusional creep of multicomponent systems. Progress report, February 1, 1980-January 31, 1981. [Dislocation-crack interactions; photoplastic and electroplastic effects in KCl]

Description: Topics for which significant results are reported include dislocation-crack interactions, impression creep of Al polycrystals, and photoplastic and electroplastic effects in additively colored KCl. 9 figures. (DLC)
Date: January 1, 1981
Creator: Li, J.C.M.
Partner: UNT Libraries Government Documents Department

Diffusional creep of multicomponent systems. Progress report, February 1, 1978--January 31, 1979

Description: The achievements this year can be summarized as follows: (1) Successful completion of photoelastic studies of three dimensional stress field caused by a cylindrical punch. (2) Successful completion of pencil slip studies in ..beta..-Tin single crystals. (3) Equipment set up and preparation for experimental investigation of laser-excited diffusion and creep in solids. No positive results yet. Some negative results are described.
Date: January 1, 1979
Creator: Li, J.C.M.
Partner: UNT Libraries Government Documents Department

Diffusional creep of multicomponent systems. Progress report, February 1, 1976--January 31, 1977. [Impression (indentation) creep]

Description: Impression creep was established as a reliable substitute for conventional creep testing using bulk specimens. Impression creep tests on succinonitrile crystals established the stress and temperature dependences which agreed with literature values. Conventional compression creep confirmed the results. From the computer program of impression creep using finite element method, the calculated impressing velocities agreed with experimental values. Such agreement established the impression creep condition in the power law creep regime and suggested a punch size dependence which was confirmed by experiment. In the observation of plastic zone in LiF after impression creep, dislocation etch pit techniques were used to reveal plastic zone size under the punch. It provided the experimental evidence and also confirmed the correlation between impression creep and conventional creep tests. Studies on hydrogen embrittlement and a review paper on solute defect interactions were completed. In the new mechanism of hydrogen embrittlement, a theoretical prediction of ductility can be achieved. (DLC)
Date: January 1, 1976
Creator: Li, J. C. M.
Partner: UNT Libraries Government Documents Department

Methods development for separation of inorganic anions, organic acids and bases, and neutral organic compounds by ion chromatography and capillary electrophoresis

Description: A novel anion-exchange resin containing three amine groups was prepared by reaction of a chloromethylated polystyrene-divinylbenzene (PS-DVB) resin with diethylenetriamine. After being protonated by contact with an aqueous acid, this resin can be used for ion chromatographic separation of anions. The charge on the resins can be varied from +1 to +3 by changing the mobile phase pH. The selectivity of the new ion exchangers for various inorganic anions was quite different from that of conventional anion exchangers. The performance of this new anion exchanger was studied by changing the pH and the concentration of the eluent, and several different eluents were used with some common anions as testing analytes. Conductivity detection and UV-visible detection were applied to detect the anions after separation. The new resin can also be used for HPLC separation of neutral organic compounds. Alkylphenols and alkylbenzenes were separated with this new polymeric resin, and excellent separations were obtained under simple conditions. This report contains Chapter 1: General introduction and Chapter 6: General conclusions.
Date: April 1, 1999
Creator: Li, J.
Partner: UNT Libraries Government Documents Department

Design, construction, establishment of proof of principle, and testing of a spectrometer to permit spectroelectrochemical investigations of actinides in a confined system

Description: This study examines the design, construction, and performance of a spectrometer that was designed and built for UV-visible absorption spectroscopic studies in molten salt media. Contrary to previous designs in the literature, the authors found that furnace and chemical components can be located away from the instrument and electronics. In studying the performance of the spectrometer, they used a potassium chloride eutectic mixture as the molten salt medium. They found that UV-visible absorption spectroscopic studies can be conveniently created in a molten alkali halide media with inexpensive equipment coupled with good sensitivity and precision. Further research will focus on designing a suitable fiber optic probe that will allow the authors to monitor the molten salt process on-line.
Date: February 1, 1999
Creator: Dasgupta, P. K. & Li, J.
Partner: UNT Libraries Government Documents Department

Microstructural behavior of nonequilibrium systems

Description: In this report, achievements for the period of March 1, 1989 to February 28, 1992 is reported. Topics discussed include: nanoporous glass, dislocations in amorphous metals, fracture of composite materials, superparamagnetism, atomic force microscopy, and metallic glasses.
Date: September 1, 1991
Creator: Li, J.C.M.
Partner: UNT Libraries Government Documents Department

Microstructural behavior of nonequilibrium systems. Final report, March 1, 1986--May 31, 1993

Description: The major achievements made during this period are as follows: (1) negative creep in metallic glasses and mechanochemical spinodal decomposition; (2) magnetic domain structure at shear bands and annealing embrittlement of metallic glasses; (3) etch pits along shear bands in metallic glasses; (4) increase of Curie temperature by rapid heating; (5) molecular dynamics simulation of melting; (6) nanoporous materials; (7) dislocation-crack interactions; (8) recovery processes of deformed structure; and (9) differences in deformation mechanisms between metals and polymers. A brief discussion is given for each achievement.
Date: November 1, 1994
Creator: Li, J. C. M.
Partner: UNT Libraries Government Documents Department

Fusion-Fission Research Facility (FFRF) as a Practical Step Toward Hybrids

Description: The project of ASIPP (with PPPL participation), called FFRF, (R/a=4/1 m/m, Ipl=5 MA, Btor=4-6 T, PDT=50-100 MW, Pfission=80-4000 MW, 1 m thick blanket) is outlined. FFRF stands for the Fusion-Fission Research Facility with a unique fusion mission and a pioneering mission of merging fusion and fission for accumulation of design, experimental, and operational data for future hybrid applications. The design of FFRF will use as much as possible the EAST and ITER design experience. On the other hand, FFRF strongly relies on new, Lithium Wall Fusion plasma regimes, the development of which has already started in the US and China.
Date: November 18, 2010
Creator: Zakharov, L.; Li, J. & Wu, Y.
Partner: UNT Libraries Government Documents Department

Observations And Measurements of Anomalous Hollow Electron Beams in a Storage Ring

Description: Anomalous hollow electron beams have been recently observed in the Duke storage ring. With a single bunch beam in a lattice with a negative chromaticity, a hollow beam can be created. This beam consists of a solid core beam inside and a large ring beam outside. In this paper, we report the measurements of the hollow beam phenomenon, including its distinct image pattern and spectrum signature, and its evolution with time. By capturing the post-instability bursting beam, the hollow beam is a unique model system for studying transverse instabilities, in particular, the interplay of the wakefield and lattice nonlinearity. The hollow beam can also be used as a tool to study linear and nonlinear particle dynamics in the storage ring.
Date: February 6, 2006
Creator: Wu, Y.K.; Li, J.; U., /Duke; Wu, J. & /SLAC
Partner: UNT Libraries Government Documents Department

U.S. Department of Energy Critical Materials Strategy

Description: This report examines the role of rare earth metals and other materials in the clean energy economy. It was prepared by the U.S. Department of Energy (DOE) based on data collected and research performed during 2010. Its main conclusions include: (a) Several clean energy technologies -- including wind turbines, electric vehicles, photovoltaic cells and fluorescent lighting -- use materials at risk of supply disruptions in the short term. Those risks will generally decrease in the medium and long term. (b) Clean energy technologies currently constitute about 20 percent of global consumption of critical materials. As clean energy technologies are deployed more widely in the decades ahead, their share of global consumption of critical materials will likely grow. (c) Of the materials analyzed, five rare earth metals (dysprosium, neodymium, terbium, europium and yttrium), as well as indium, are assessed as most critical in the short term. For this purpose, 'criticality' is a measure that combines importance to the clean energy economy and risk of supply disruption. (d) Sound policies and strategic investments can reduce the risk of supply disruptions, especially in the medium and long term. (e) Data with respect to many of the issues considered in this report are sparse. In the report, DOE describes plans to (i) develop its first integrated research agenda addressing critical materials, building on three technical workshops convened by the Department during November and December 2010; (ii) strengthen its capacity for information-gathering on this topic; and (iii) work closely with international partners, including Japan and Europe, to reduce vulnerability to supply disruptions and address critical material needs. DOE will work with other stakeholders -- including interagency colleagues, Congress and the public -- to shape policy tools that strengthen the United States' strategic capabilities. DOE also announces its plan to develop an updated critical materials strategy, ...
Date: December 1, 2010
Creator: Bauer, D.; Diamond, D.; Li, J.; Sandalow, D.; Telleen, P. & Wanner, B.
Partner: UNT Libraries Government Documents Department

IEC International Standards Under Development For Radiation-Generating Devices

Description: The International Electrotechnical Commission (IEC) is the leading and oldest global organization with over 100 years history of developing and publishing international standards for all electrical, electronic and related technologies, including radiation detection instrumentation. Subcommittee 45B 'Radiation Protection Instrumentation' of the IEC has recently started the development of two standards on radiation-generating devices. IEC 62463 'Radiation protection instrumentation--X-ray Systems for the Screening of Persons for Security and the Carrying of Illicit Items' is applicable to X-ray systems designed for screening people to detect if they are carrying objects such as weapons, explosives, chemical and biological agents and other concealed items that could be used for criminal purposes, e.g. terrorist use, drug smuggling, etc. IEC 62523 'Radiation protection instrumentation--Cargo/Vehicle radiographic inspection systems' applies to cargo/vehicle imaging inspection systems using accelerator produced X-ray or gamma radiation to obtain images of the screened objects (e.g. cargo containers, transport and passenger vehicles and railroad cars). The objective of both standards is to specify standard requirements and general characteristics and test procedures, as well as, radiation, electrical, environmental, mechanical, and safety requirements and to provide examples of acceptable methods to test these requirements. In particular the standards address the design requirements as they relate to the radiation protection of the people being screened, people who are in the vicinity of the equipment and the operators. The standard IEC 62463 does not deal with the performance requirements for the quality of the object detection. Compliance with the standards requirements will provide the manufacturers with internationally acceptable specifications and the device users with assurance of the rigorous quality and accuracy of the measurements in relation to the radiological safety of the equipment. The main characteristics of IEC 62463 and IEC 62523 standards are presented and as well as the IEC methodology of standard development and approval.
Date: December 6, 2007
Creator: Voytchev, M; Radev, R; Chiaro, P; Thomson, I; Dray, C & Li, J
Partner: UNT Libraries Government Documents Department

Design of Shallow P-Type Dopants in ZnO: Preprint

Description: This paper describes approaches to lower the acceptor ionization energy in ZnO by codoping acceptors with donor or isovalent atoms and proposes a universal approach to overcome the doping polarity problem for wide-band-gap semiconductors.
Date: May 1, 2008
Creator: Wei, S.-H.; Li, J. & Yan, Y.
Partner: UNT Libraries Government Documents Department

National Ignition Facility and Managing Location, Component, and State

Description: The National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory is a stadium-sized facility that contains a 192-beam, 1.8-Megajoule, 500-Terawatt, ultraviolet laser system coupled with a 10-meter diameter target chamber. There are over 6,200 Line Replaceable Units (LRUs) comprised of more than 104,000 serialized parts that make up the NIF. Each LRU is a modular unit typically composed of a mechanical housing, laser optics (glass, lenses, or mirrors), and utilities. To date, there are more than 120,000 data sets created to characterize the attributes of these parts. Greater than 51,000 Work Permits have been issued to install, maintain, and troubleshoot the components. One integrated system is used to manage these data, and more. The Location Component and State (LoCoS) system is a web application built using Java Enterprise Edition technologies and is accessed by over 1,200 users. It is either directly or indirectly involved with each aspect of NIF work activity, and interfaces with ten external systems including the Integrated Computer Control System (ICCS) and the Laser Performance Operations Model (LPOM). Besides providing business functionality, LoCoS also acts as the NIF enterprise service bus. In this role, numerous integration approaches had to be adopted including: file exchange, database sharing, queuing, and web services in order to accommodate various business, technical, and security requirements. Architecture and implementation decisions are discussed.
Date: July 25, 2011
Creator: Foxworthy, C; Fung, T; Beeler, R; Li, J; Dugorepec, J & Chang, C
Partner: UNT Libraries Government Documents Department

A new 3D parallel high resolution electromagnetic nonlinear inversion based on new global magnetic integral and local differential decomposition (GILD)

Description: A new 3D electromagnetic modeling and nonlinear inversion algorithm is presented based on global integral and local differential equations decomposition (GILD). The GILD parallel nonlinear inversion algorithm consists of five parts: (1) the domain is decomposed into subdomain SI and subdomain SII; (2) a new global magnetic integral equation in SI and the local magnetic differential equations IN SII will be used together to obtain the magnetic field in the modeling step; (3) the new global magnetic integral Jacobian equation in SI and the local magnetic differential Jacobian equations in SII will be used together to update the electric conductivity and permittivity from the magnetic field data in the inversion step; (4) the subdomain SII can naturally and uniformly be decomposed into 2{sup n} smaller sub-cubic-domains; the sparse matrix in each sub-cubic-domain can be eliminated separately, in parallel; (5) a new parallel multiple hierarchy substructure algorithm will be used to solve the smaller full matrices in SI, in parallel. The applications of the new 3D parallel GILD EM modeling and nonlinear inversion algorithm and software are: (1) to create high resolution controlled-source electric conductivity and permittivity imaging for interpreting electromagnetic field data acquired from cross hole, surface to borehole, surface to surface, single hole, and multiple holes; (2) to create the magnetotelluric high resolution imaging from the surface impedance and field data. The new GILD parallel nonlinear inversion will be a 3D/2.5D powerful imaging tool for the oil geophysical exploration and environmental remediation and monitoring.
Date: May 1, 1997
Creator: Xie, G. & Li, J.
Partner: UNT Libraries Government Documents Department

High quality muon detection for the SSC

Description: We present an alternative approach for muon detection at the SSC based on a high field magnet (B = 5 Tesla) of ``moderate`` dimensions (radius = 3.5 m; overall length = 15 meters). A precision determination of a muon`s momentum is made using a point-slope method, where the point is the interaction point and the slope is the direction of the muon`s track as it exits the magnet coil. Momentum resolutions on the order of {Delta}p{sub t}/p{sub t} {approx_equal} 4% are possible over large solid angles for muon momenta as high as 1 TeV with rather modest alignment ({approximately} 200,{mu}m) tolerances, with standard drift chamber resolutions ({approximately} 100{mu}m), and with no reliance on the performance of an inner tracking system. Robustness is provided by additional momentum measurements in the inner tracker and in a solid iron spectrometer utilizing the magnet`s return yoke. The total cost of the system, including proper magnetic shielding for the magnet and a forward-backward iron-core toroid muon detection system with {Delta}p/p {approx_equal} 9%, is comparable to that of the low-field L*/GEM approach that does not provide a magnetic flux return nor a forward-backward iron system. The magnet leaves the same amount of space for inner detector items as does the large, low-field L*-type system, while providing a substantially higher magnetic field in the inner tracking volume.
Date: January 1, 1992
Creator: Gao, W.X.; Li, J. & Mao, Z.P.
Partner: UNT Libraries Government Documents Department

New 3D parallel GILD electromagnetic modeling and nonlinear inversion using global magnetic integral and local differential equation

Description: This paper describes a new 3D parallel GILD electromagnetic (EM) modeling and nonlinear inversion algorithm. The algorithm consists of: (a) a new magnetic integral equation instead of the electric integral equation to solve the electromagnetic forward modeling and inverse problem; (b) a collocation finite element method for solving the magnetic integral and a Galerkin finite element method for the magnetic differential equations; (c) a nonlinear regularizing optimization method to make the inversion stable and of high resolution; and (d) a new parallel 3D modeling and inversion using a global integral and local differential domain decomposition technique (GILD). The new 3D nonlinear electromagnetic inversion has been tested with synthetic data and field data. The authors obtained very good imaging for the synthetic data and reasonable subsurface EM imaging for the field data. The parallel algorithm has high parallel efficiency over 90% and can be a parallel solver for elliptic, parabolic, and hyperbolic modeling and inversion. The parallel GILD algorithm can be extended to develop a high resolution and large scale seismic and hydrology modeling and inversion in the massively parallel computer.
Date: July 1, 1998
Creator: Xie, G.; Li, J.; Majer, E. & Zuo, D.
Partner: UNT Libraries Government Documents Department

New 3D parallel SGILD modeling and inversion

Description: In this paper, a new parallel modeling and inversion algorithm using a Stochastic Global Integral and Local Differential equation (SGILD) is presented. The authors derived new acoustic integral equations and differential equation for statistical moments of the parameters and field. The new statistical moments integral equation on the boundary and local differential equations in domain will be used together to obtain mean wave field and its moments in the modeling. The new moments global Jacobian volume integral equation and the local Jacobian differential equations in domain will be used together to update the mean parameters and their moments in the inversion. A new parallel multiple hierarchy substructure direct algorithm or direct-iteration hybrid algorithm will be used to solve the sparse matrices and one smaller full matrix from domain to the boundary, in parallel. The SGILD modeling and imaging algorithm has many advantages over the conventional imaging approaches. The SGILD algorithm can be used for the stochastic acoustic, electromagnetic, and flow modeling and inversion, and are important for the prediction of oil, gas, coal, and geothermal energy reservoirs in geophysical exploration.
Date: September 1, 1998
Creator: Xie, G.; Li, J. & Majer, E.
Partner: UNT Libraries Government Documents Department