The paper follows the history of a neutral atom or molecule into a plasma--ionization, dissociation, radiation,--until it becomes a set of charged particles moving in the electromagnetic fields of the plasma system. The various useful forms of the method of averaging are displayed and applied to calculation of constants of motion. The breakdown of these constants is discussed along with some of the implications for fusion systems.

The intermediate energy neutron flux existing outside the biological shielding of reactors has not been studied to any great extent previous to this time, because of the lack of an instrument capable of detecting neutrons in the intermediate energy range. The instrument used at the MTR utilizes polyethylene spheres of various sizes to give different amounts of moderation and absorption to the impinging neutrons. A procedure for the approximate determination of the relative number of intermediate energy and fast neutrons is given. By graphical methods the following information is obtained: (1) fraction of intermediate neutrons, (2) fraction of fast neutrons, and (3) the approximate average energy of the fast neutrons. Since the instrument described can be used to determine the thermal neutron flux independent of intermediate and fast fluxes, only one instrument is required to determine the neutron flux in all three energy ranges. Dose calculations indicate the intermediate range neutrons give a dose greater than the dose delivered by fast neutrons around the MTR-ETR reactors under normal operating conditions. (auth)

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The nature of the electrical discharge has an obvious impact upon the gas efficiency of an ion source and on the current density whch can be drawn from it. However external factors, such as the conductance of the grids and the background pressure along the beamline, also have an effect. Simple approximations based upon these factors show that there is a lower limit to the pressure of an ion source, which can deliver an ion beam of given current density at a specific gas efficiency. Estimates of ion stripping losses in a double gridded structure show that for all practical purposes, there is an upper limit as well.

The Policy Analysis Screening System (PASS) is a computerized information-retrieval system designed to provide analysts in the Department of Energy, Assistant Secretary for Environment, Office of Technology Impacts (DOE-ASEV-OTI) with automated access to articles, computer simulation outputs, energy-environmental statistics, and graphics. Although it is essential that PASS respond quickly to user queries, problems at the computer facility where it was originally installed seriously slowed PASS's operations. Users attempting to access the computer by telephone repeatedly encountered busy signals and, once logged on, experienced unsatisfactory delays in response to commands. Many of the problems stemmed from the system's facility manager having brought another large user onto the system shortly after PASS was implemented, thereby significantly oversubscribing the facility. Although in March 1980 Energy Information Administration (EIA) transferred operations to its own computer facility, OTI has expressed concern that any improvement in computer access time and response time may not be sufficient or permanent. Consequently, a study was undertaken to assess the current status of the system, to identify alternative computer environments, and to evaluate the feasibility of each alternative in terms of its cost and its ability to alleviate current problems.

Two diode designs are being studied that require basically different fabrication techniques. The fabrication of electrodes was begun to test the concepts and the feasibility of these designs. This work was done with polished molybdenum electrode surfaces and vapor-deposited alumina insulator structures. Initial results were obtained in the close spacing of molybdenum electrodes with alumina insulators. Spacings were demonstrated with 1/2-inch diameter discs in the range of 3 to 5 ..mu..m, using 1-..mu..m thick insulators. The deposition of thin alumina films on a molybdenum substrate was demonstrated, upon which arrays of thin film electrodes about 1/32-inch in diameter were deposited. A second approach uses a thin film as one of the electrodes. An analysis of the thermal and electrical transport properties of 1-..mu..m thick tungsten film shows that edge-connected films about 1 mm square in area could withstand the stresses generated by differential thermal expansion when the film is attached to the opposite electrode by stand-off insulators.

Pendeo-epitaxy has been applied to nonpolar a-plane GaN layers in order to observe if such process will lead to defect reduction in comparison with direct growth on this plane. Uncoalesced and coalesced a-plane GaN layers with thicknesses 2{micro}m and 12{micro}m, respectively have been studied by conventional and high resolution electron microscopy. The following structural defects have been observed in pendeo-epitaxial layers: (1) basal stacking faults, (2) threading dislocations and (3) prismatic stacking faults. Drastic decrease of threading dislocation density and stacking faults have been observed in 'wing' areas with respect to 'seed' areas. Cross-section images reveal cracks and voids at the areas where two coalesced wings meet each other. High resolution electron microscopy shows that the majority of stacking faults are low-energy planar defects of the types I{sub 1}, I{sub 2} and I{sub 3}. The I{sub 3} type basal stacking fault, predicted theoretically, has been observed experimentally for the first time.

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A 1D model of space-charge impedance, assuming atransversely uniform beam with circular cross-section, has been proposedand is being extensively used in the modelling of the microbunchinginstability of relevance for the beam delivery systems of x-ray FELs. Inthis paper we investigate the limitation of the model when applied tostudying the effect of shot noise--one of the sources of themicrobunching instability. We make comparison witha fully 3D calculationand identify the upper end of the frequency spectrum for applicability ofthe 1D model. Relaxation of the assumptions regarding axis-symmetry anduniformity of the transverse density is also reviewed.

The authors measure the time-dependent CP asymmetry parameters in B{sup 0} {yields} K{sup +}K{sup -}K{sup 0} based on a data sample of approximately 277 million B-meson pairs recorded at the {Upsilon}(4S) resonance with the BABAR detector at the PEP-II B-meson Factory at SLAC. They reconstruct two-body B{sup 0} decays to {phi}(1020)K{sub s}{sup 0} and {phi}(1020)K{sub L}{sup 0}. Using a time-dependent maximum-likelihood fit, they measure sin2{beta}{sub eff}({phi}K{sup 0}) = 0.48 {+-} 0.28 {+-} 0.10, and C({phi}K{sup 0}) = 0.16 {+-} 0.25 {+-} 0.09, where the first error is statistical, and the second is systematic. They also present measurements of the CP-violating asymmetries in the decay B{sup 0} {yields} f{sub 0}({yields} {pi}{sup +}{pi}{sup -})K{sub s}{sup 0}. The results are obtained from a data sample of 209 x 10{sup 6} {Upsilon}(4S) {yields} B{bar B} decays, also collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. From a time-dependent maximum-likelihood fit they measure the mixing-induced CP violation parameter S(f{sub 0}(980)K{sub S}{sup 0}) = - sin 2{beta}{sub eff}f{sub 0}(980)K{sub S}{sup 0} = -0.95{sub -0.23}{sup +0.32} {+-} 0.10 and the direct CP violation parameter C(f{sub 0}(980)K{sub S}{sup 0}) = - 0.24 {+-} 0.31 {+-} 0.15, where the first errors are statistical and …

A crucial step in human breast cancer progression is the acquisition of invasiveness. There is a distinct lack of human cell culture models to study the transition from pre-invasive to invasive phenotype as it may occur 'spontaneously' in vivo. To delineate molecular alterations important for this transition, we isolated human breast epithelial cell lines that showed partial loss of tissue polarity in three-dimensional reconstituted-basement membrane cultures. These cells remained non-invasive; however, unlike their non-malignant counterparts, they exhibited a high propensity to acquire invasiveness through basement membrane in culture. The genomic aberrations and gene expression profiles of the cells in this model showed a high degree of similarity to primary breast tumor profiles. The xenograft tumors formed by the cell lines in three different microenvironments in nude mice displayed metaplastic phenotypes, including squamous and basal characteristics, with invasive cells exhibiting features of higher grade tumors. To find functionally significant changes in transition from pre-invasive to invasive phenotype, we performed attribute profile clustering analysis on the list of genes differentially expressed between pre-invasive and invasive cells. We found integral membrane proteins, transcription factors, kinases, transport molecules, and chemokines to be highly represented. In addition, expression of matrix metalloproteinases MMP-9,-13,-15,-17 was up regulated …

The physical and electrochemical properties of LixMnO2 and LixTi0.11Mn0.89O2 synthesized from precursors made by glycine-nitrate combustion (GNC) and solid-state synthesis methods (SS) are examined in this paper. The highest specific capacities in lithium cells are obtained for SS-LixMnO2 electrodes at low current densities, but GNC-LixTi0.11Mn0.89O2 electrodes show the best high rate performance. These results can be explained by changes in the voltage characteristics and differences in the particle morphologies induced by the Ti-substitution and synthesis method. Ti-substitution also results in a decrease in the electronic conductivity, but greatly improves the thermal properties and imparts dissolution resistance to the electrode. For these reasons, it is preferable to use LixTi0.11MnO0.89O2 in lithium battery configurations rather than LixMnO2. Suggestions for improving the electrochemical performance of the Ti-substituted variant are given based on the results described herein.

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When a networked polymeric composite under high stress is subjected to irradiation, the resulting chemical changes like chain scissioning and cross-link formation can lead to permanent set and altered elastic modulus. Using a commercial silicone elastomer as a specific example we show that a simple 2-stage Tobolsky model in conjunction with Fricker's stress-transfer function can quantitatively reproduce all experimental data as a function of radiation dosage and the static strain at which radiation is turned on, including permanent set, stress-strain response, and net cross-linking density.

China has ambitious goals for economic development, and mustfind ways to power the achievement of those goals that are bothenvironmentally and socially sustainable. Integration into the globaleconomy presents opportunities for technological improvement and accessto energy resources. China also has options for innovative policies andmeasures that could significantly alter the way energy is acquired andused. These opportunities andoptions, along with long-term social,demographic, and economic trends, will shape China s future energysystem, and consequently its contribution to emissions of greenhousegases, particularly carbon dioxide (CO2). In this study, entitled China sSustainable Energy Future: Scenarios of Energy and Carbon Emissions, theEnergy Research Institute (ERI), an independent analytic organizationunder China's Na tional Development and Reform Commission (NDRC), soughtto explore in detail how China could achieve the goals of the TenthFive-Year Plan and its longer term aims through a sustainable developmentstrategy. China's ability to forge a sustainable energy path has globalconsequences. China's annual emissions of greenhouse gases comprisenearly half of those from developing countries, and 12 percent of globalemissions. Most of China's greenhouse gas emissions are in the form ofCO2, 87 percent of which came from energy use in 2000. In that year,China's carbon emissions from energy use and cement production were 760million metric tons (Mt-C), …

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Molecular dynamics is employed to study the low energy states of a beam of charged particles subject to circumferentially varying guiding and focusing forces and with Coulomb forces between the particles. In a constant gradient ring, the lowest energy state is never ordered, but in an alternating gradient structure, operating below the transition energy, the lowest state is ordered. The nature and characteristics of the ground state depends upon the beam density and the ring parameters. For zero temperature the crystal remains intact for a very long time, but at nonzero temperatures it gains energy from the lattice. A critical temperature exists above which the crystal melts rapidly.

We describe a Nanostructure-Initiator Mass Spectrometry (NIMS) enzymatic (Nimzyme) assay in which enzyme substrates are immobilized on the mass spectrometry surface by using fluorous-phase interactions. This 'soft' immobilization allows efficient desorption/ionization while also enabling the use of surface-washing steps to reduce signal suppression from complex biological samples, which results from the preferential retention of the tagged products and reactants. The Nimzyme assay is sensitive to subpicogram levels of enzyme, detects both addition and cleavage reactions (sialyltransferase and galactosidase), is applicable over a wide range of pHs and temperatures, and can measure activity directly from crude cell lysates. The ability of the Nimzyme assay to analyze complex mixtures is illustrated by identifying and directly characterizing {beta}-1,4-galactosidase activity from a thermophilic microbial community lysate. The optimal enzyme temperature and pH were found to be 65 C and 5.5, respectively, and the activity was inhibited by both phenylethyl-{beta}-d-thiogalactopyranoside and deoxygalactonojirimycin. Metagenomic analysis of the community suggests that the activity is from an uncultured, unsequenced {gamma}-proteobacterium. In general, this assay provides an efficient method for detection and characterization of enzymatic activities in complex biological mixtures prior to sequencing or cloning efforts. More generally, this approach may have important applications for screening both enzymatic and …

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High resolution mass spectrometers are specialized systems that allow researchers to determine the exact mass of samples to four significant digits by using magnetic and electronic sector mass analyzers. Many of the systems in use today at research laboratories and universities were designed and built more than two decades ago. The manufacturers of these systems have abandoned the support for some of the mass spectrometers and parts to power and control them have become scarce or obsolete. The Savannah River National Laboratory has been involved in the upgrade of the electronics and software for these legacy machines. The Electronics Upgrade of High Resolution Mass Spectrometers consists of assembling high-end commercial instrumentation from reputable manufacturers with a minimal amount of customization to replace the electronics for the older systems. By taking advantage of advances in instrumentation, precise magnet control can be achieved using high resolution current sources and continuous feedback from a high resolution hall-effect probe. The custom equipment include a precision voltage divider/summing amplifier chassis, high voltage power supply chassis and a chassis for controlling the voltage emission for the mass spectrometer source tube. The upgrade package is versatile enough to interface with valve control, vacuum and other instrumentation. Instrument …

The Integrated Status and Effectiveness Monitoring Program (ISEMP-BPA project No.2003-0017) has been created as a cost effective means of developing protocols and new technologies, novel indicators, sample designs, analytical, data management and communication tools and skills, and restoration experiments that support the development of a region-wide Research, Monitoring and Evaluation (RME) program to assess the status of anadromous salmonid populations, their tributary habitat and restoration and management actions. The most straightforward approach to developing a regional-scale monitoring and evaluation program would be to increase standardization among status and trend monitoring programs. However, the diversity of species and their habitat, as well as the overwhelming uncertainty surrounding indicators, metrics, and data interpretation methods, requires the testing of multiple approaches. Thus, the approach ISEMP has adopted is to develop a broad template that may differ in the details among subbasins, but one that will ultimately lead to the formation of a unified RME process for the management of anadromous salmonid populations and habitat across the Columbia River Basin. ISEMP has been initiated in three pilot subbasins, the Wenatchee/Entiat, John Day, and Salmon. To balance replicating experimental approaches with the goal of developing monitoring and evaluation tools that apply as broadly as possible …

Extended X-Ray Absorption Fine Structure (EXAFS), using a laser-imploded target as a source, can yield the properties of laser-shocked metals on a nanosecond time scale. EXAFS measurements of vanadium shocked to {approx}0.4 Mbar yield the compression and temperature in good agreement with hydrodynamic simulations and shock-speed measurements. In laser-shocked titanium at the same pressure, the EXAFS modulation damping is much higher than warranted by the predicted temperature increase. This is shown to be due to the {alpha}-Ti to {omega}-Ti crystal-phase transformation, known to occur below {approx}0.1 Mbar for slower shock waves. The dynamics of material response to shock loading has been extensively studied in the past [1]. The goal of those studies has been to understand the shock-induced deformation and structural changes at the microscopic level [2]. Laser-generated shocks can be employed to broaden these studies to higher pressures ({approx}1 Mbar) and strain rates ({approx} 10{sup 7}-10{sup 8} s{sup -1}). Recently, laser-shocked materials have been studied with in-situ x-ray diffraction [3,4]. The goal of this work is to examine the use of in-situ EXAFS [5] as a complementary characterization of laser-shocked metals. EXAFS is the modulation in the x-ray absorption above the K edge (or L edge) due to the …