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Web-Ice: Integrated Data Collection and Analysis for Macromolecular Crystallography

Description: New software tools are introduced to facilitate diffraction experiments involving largenumbers of crystals. While existing programs have long provided a framework for lattice indexing, Bragg spot integration, and symmetry determination, these initial data processing steps often require significant manual effort. This limits the timely availability of data analysis needed for high-throughput procedures, including the selection of the best crystals from a large sample pool, and the calculation of… more
Date: October 10, 2007
Creator: Gonzalez, Ana; Gonzalez, Ana; Moorhead, Penjit; McPhillips, Scott E.; Song, Jinhu; Sharp, Ken et al.
Partner: UNT Libraries Government Documents Department
open access

InN Nanorods Grown on Different Planes of Al2O3

Description: No Description Available.
Date: March 10, 2007
Creator: Liliental-Weber, Z.; Park, H.J.; Mangum, J.; Anderson, T. & Kryliouk, O.
Partner: UNT Libraries Government Documents Department
open access

Shape Determination for Deformed Electromagnetic Cavities

Description: The measured physical parameters of a superconducting cavity differ from those of the designed ideal cavity. This is due to shape deviations caused by both loose machine tolerances during fabrication and by the tuning process for the accelerating mode. We present a shape determination algorithm to solve for the unknown deviations from the ideal cavity using experimentally measured cavity data. The objective is to match the results of the deformed cavity model to experimental data through least-… more
Date: December 10, 2007
Creator: Akcelik, Volkan; Ko, Kwok; Lee, Lie-Quan; Li, Zhenghai; Ng, Cho-Kuen & Xiao, Liling
Partner: UNT Libraries Government Documents Department
open access

The polarized SRF gun experiment.

Description: RF electron guns are capable of producing electron bunches with high brightness, which outperform DC electron guns and may even be able to provide electron beams for the ILC without the need for a damping ring. However, all successful existing guns for polarized electrons are DC guns because the environment inside an RF gun is hostile to the GaAs cathode material necessary for polarization. While the typical vacuum pressure in a DC gun is better than 10{sup -11} torr the vacuum in an RF gun is … more
Date: September 10, 2007
Creator: Kewisch, J.; Ben-Zvi, Ilan; Rao, T.; Burrill, A.; Pate, D.; Grover, R. et al.
Partner: UNT Libraries Government Documents Department
open access

The Formation of Contact and Very Close Binaries

Description: We explore the possibility that all close binaries, i.e. those with periods {approx}< 3 d, including contact (W UMa) binaries, are produced from initially wider binaries (periods of say 10's of days) by the action of a triple companion through the medium of Kozai Cycles with Tidal Friction (KCTF).
Date: August 10, 2007
Creator: Kisseleva-Eggleton, L & Eggleton, P P
Partner: UNT Libraries Government Documents Department
open access

Plasma Suppression of Large Scale Structure Formation in the Universe

Description: We point out that during the reionization epoch of the cosmic history, the plasma collective effect among the ordinary matter would suppress the large scale structure formation. The imperfect Debye shielding at finite temperature would induce a residual long-range electrostatic potential which, working together with the baryon thermal pressure, would counter the gravitational collapse. As a result the effective Jean's length, {tilde {lambda}}{sub J}, is increased by a factor, {tilde {lambda}}{s… more
Date: December 10, 2007
Creator: Chen, Pisin & Lai, Kwang-Chang
Partner: UNT Libraries Government Documents Department
open access

Lactonization and protonation of gluconic acid: a thermodynamicand kinetic study by potentiometry, nmr and esi-ms

Description: In acidic aqueous solutions, gluconate protonation is coupled with lactonization of gluconic acid. With the decrease of pC{sub H}, two lactones ({delta}/{gamma}) are sequentially formed. The {delta}-lactone forms more readily than the {gamma}-lactone. In 0.1 M gluconate solutions, if pC{sub H} is above 2.5, only the {delta}-lactone is generated. When pC{sub H} is decreased below 2.0, the formation of the {gamma}-lactone is observable although the {delta}-lactone predominates. At I = 0.1 M NaClO… more
Date: January 10, 2007
Creator: Zhang, Z.; Gibson, P.; Clark, S.B.; Tian, G.; Zanonato, P. & Rao, L.
Partner: UNT Libraries Government Documents Department
open access

Soft X-Ray Laser Interferometry of Colliding Laser-Created Plasmas in Semi-Cylindrical Cavities

Description: A table-top capillary discharge soft x-ray laser was used to acquire high contrast interferograms that map the evolution of dense aluminum plasmas created by laser irradiation of a 500 {micro}m diameter semi-cylindrical cavity with 120 ps optical laser pulses of {approx}1.1 x 10{sup 12} Wcm{sup -2} peak intensity. The measured electron density maps, that were compared with simulations, show that the plasma converges on axis, where it collides to form a localized region with density exceeding 1 … more
Date: December 10, 2007
Creator: Purvis, M. A.; Grava, J.; Filevich, J.; Marconi, M.; Dunn, J.; Moon, S. J. et al.
Partner: UNT Libraries Government Documents Department
open access

Anodic Behavior of SAM2X5 Material Applied as Amorphous Coatings

Description: Iron-based amorphous alloys are desirable industrial materials since they are highly resistant to corrosion and possess enhanced hardness for wear resistance. The amorphous materials can be produced from the melt as powder and later spray deposited as coatings on large engineering structures. As a laboratory experiment, SAM2X5 powder was coated on electrochemical specimens of 304SS for testing. Results show that the coated specimens did not perform satisfactorily during the laboratory testing. … more
Date: August 10, 2007
Creator: Hailey, P D; Farmer, J C; Day, S D & Rebak, R B
Partner: UNT Libraries Government Documents Department
open access

Superfluid Transition in a Chiron Gas

Description: Low temperature measurements of the magnetic susceptibility of LSCO suggest that the superconducting transition is associated with the disappearance of a vortex liquid. In this note we wish to draw attention to the fact that spin-orbit-like interactions in a poorly conducting layered material can lead to a new type of quantum ground state with spin polarized soliton-like charge carriers as the important quantum degree of freedom. In 2-dimensions these solitons are vortex-like, while in 3-dimens… more
Date: December 10, 2007
Creator: Chapline, G. F.
Partner: UNT Libraries Government Documents Department
open access

Effect of High Temperature Aging on the Corrosion Resistance of Iron Based Amorphous Alloys

Description: Iron-based amorphous alloys can be more resistant to corrosion than polycrystalline materials of similar compositions. However, when the amorphous alloys are exposed to high temperatures they may recrystallize (or devitrify) thus losing their resistance to corrosion. Four different types of amorphous alloys melt spun ribbon specimens were exposed to several temperatures for short periods of time. The resulting corrosion resistance was evaluated in seawater at 90 C and compared with the as-prepa… more
Date: August 10, 2007
Creator: Day, S D; Haslam, J J; Farmer, J C & Rebak, R B
Partner: UNT Libraries Government Documents Department
open access

Recent Progress in a Beam-Beam Simulation Code for Circular Hadron Machines

Description: While conventional tracking codes can readily provide higher-order optical quantities and give an estimate of dynamic apertures, they are unable to provide directly measurable quantities such as lifetimes and loss rates. The particle tracking framework Plibb aims at modeling a storage ring with sufficient accuracy and a sufficiently high number of turns and in the presence of beam-beam interactions to allow for an estimate of these quantities. We provide a description of new features of the cod… more
Date: September 10, 2007
Creator: Kabel, Andreas; Fischer, Wolfram & Sen, Tanaji
Partner: UNT Libraries Government Documents Department
open access

Structure of A = 10 - 13 Nuclei with Two- Plus Three-Nucleon Interactions from Chiral Effective Field Theory

Description: Properties of finite nuclei are evaluated with two-nucleon (NN) and three-nucleon (NNN) interactions derived within chiral effective field theory (EFT). The nuclear Hamiltonian is fixed by properties of the A = 2 system, except for two low-energy constants (LECs) that parameterize the short range NNN interaction. We constrain those two LECs by a fit to the A = 3 system binding energy and investigate sensitivity of {sup 4}He, {sup 6}Li, {sup 10,11}B and {sup 12,13}C properties to the variation o… more
Date: January 10, 2007
Creator: Navratil, P; Gueorguiev, V; Vary, J P; Ormand, W E & Nogga, A
Partner: UNT Libraries Government Documents Department
open access

Ionization of polarized 3He+ ions in EBIS trap with slanted electrostatic mirror.

Description: Methods of producing the nuclear polarized {sup 3}He{sup +} ions and their ionization to {sup 3}H{sup ++} in ion trap of the electron Beam Ion Source (EBIS) are discussed. Computer simulations show that injection and accumulation of {sup 3}He{sup +} ions in the EBIS trap with slanted electrostatic mirror can be very effective for injection times longer than the ion traversal time through the trap.
Date: September 10, 2007
Creator: Pikin, A.; Zelenski, A.; Kponou, A.; Alessi, J.; Beebe, E.; Prelee, K. et al.
Partner: UNT Libraries Government Documents Department
open access

p-Carbon polarimetry at RHIC.

Description: The polarization measurement through elastic ({rvec p},C) reaction plays a crucial role in the polarized proton beam operation of Relativistic Heavy Ion collider at Brookhaven National Laboratory. As well as measuring the polarization, the unknown analyzing power A{sub N} of elastic ({rvec p},C) is determined as well in combination with the absolute polarization measurement by a H-jet polarimeter. The systematic uncertainty of the Run05 measurements are discussed as well as introducing the expe… more
Date: September 10, 2007
Creator: Nakagawa,I.; Makdisi,Y.; Alekseev, I.; Bazilesky, A.; Bravar, A.; Bunce, G. et al.
Partner: UNT Libraries Government Documents Department
open access

Field evidence for strong chemical separation of contaminants in the Hanford Vadose Zone

Description: Water and chemical transport from a point source withinvadose zone sediments at Hanford were examined with a leak testconsisting of five 3800-liter aliquots of water released at 4.5 m depthevery week over a 4-week period. The third aliquot contained bromide, D2Oand 87Sr. Movement of the tracers was monitored for 9 months by measuringpore water compositions of samples from boreholes drilled 2-8 m from theinjection point. Graded sedimentary layers acting as natural capillarybarriers caused signif… more
Date: April 10, 2007
Creator: Conrad, Mark E.; DePaolo, Donald J.; Maher, Katharine; Gee,Glendon W. & Ward, Anderson L.
Partner: UNT Libraries Government Documents Department
open access

HIGH ENERGY HADRON POLARIMETRY.

Description: Proton polarimetry at RHIC uses the interference of electromagnetic (EM) and hadronic scattering amplitudes. The EM spin-flip amplitude for protons is responsible for the proton's anomalous magnetic moment, and is large. This then generates a significant analyzing power for small angle elastic scattering. RHIC polarimetry has reached a 5% uncertainty on the beam polarization, and seem capable of reducing this uncertainty further. Polarized neutron beams ax also interesting for RHIC and for a po… more
Date: September 10, 2007
Creator: BUNCE,G.
Partner: UNT Libraries Government Documents Department
open access

Absolute Polarimetry at RHIC

Description: Precise and absolute beam polarization measurements are critical for the RHIC spin physics program. Because all experimental spin-dependent results are normalized by beam polarization, the normalization uncertainty contributes directly to final physics uncertainties. We aimed to perform the beam polarization measurement to an accuracy Of {Delta}P{sub beam}/P{sub beam} < 5%. The absolute polarimeter consists of Polarized Atomic Hydrogen Gas Jet Target and left-right pairs of silicon strip det… more
Date: September 10, 2007
Creator: Okada, H.; Bravar, A.; Bunce, G.; Gill, R.; Huang, H.; Makdisi, Y. et al.
Partner: UNT Libraries Government Documents Department
open access

Sona transition studies in the RHIC OPPIS.

Description: In Optically Pumped Polarized Ion Sources (OPPIS), the atomic beam is first electron polarized, and then this polarization is transferred to the nucleus by a suitable perturbing magnetic field. In the BNL OPPIS, the electron polarized atomic beam experiences the perturbing field when it traverses a region where the axial magnetic field reverses direction in a controlled manner, strength and gradient. This is the so-called Sona Transition region, named after P. G. Sona, who fist suggested the te… more
Date: September 10, 2007
Creator: Kponou,A.; Zelenski, A.; Kokhanovski, S. & Zubets, V.
Partner: UNT Libraries Government Documents Department
open access

Influence of interface exchange coupling in perpendicular anisotropy [Pt/Co]50/TbFe bilayers

Description: We present the magnetization evolution of perpendicular anisotropy TbFe and [Co/Pt]{sub 50} thin films either in direct contact resulting in antiferromagnetic interfacial coupling or separated by a thick Pt layer. Magnetometry and x-ray magnetic circular dichroism spectroscopy determine the spatially averaged magnetic properties. Resonant magnetic x-ray small-angle scattering and magnetic soft X-ray transmission microscopy probed the domain configurations and correlations in the reversal proces… more
Date: October 10, 2007
Creator: Mangin, S.; Hauet, T.; Fischer, P.; Kim, D.H.; Kortright, J.B.; Chesnel, K. et al.
Partner: UNT Libraries Government Documents Department
open access

Cyclic and Linear Polarization of Yttrium-Containing Iron-Based Amorphous Alloys

Description: Iron-based amorphous alloys are produced by rapid solidification from the melt. These alloys may possess unique mechanical and corrosion resistant properties. The chemical composition of the alloy may influence the cooling rate that is necessary for the alloys to be completely vitreous. At the same time, the corrosion resistance of the amorphous alloys may also depend on their chemical composition. This paper examines the anodic behavior of iron-based amorphous alloys containing three different… more
Date: August 10, 2007
Creator: Day, S D; Lian, T; Farmer, J C & Rebak, R B
Partner: UNT Libraries Government Documents Department
open access

The RHIC Optically-Pumped Polarized H Ion Source.

Description: The depolarization factors in the multi-step spin-transfer polarization technique and basic limitations on maximum polarization in the OPPIS (Optically-Pumped Polarized H{sup -} Ion Source) are discussed. Detailed studies of polarization losses in the RHIC OPPIS and the source parameters optimization resulted in the OPPIS polarization increase to 86-90%. This contributed to increasing polarization in the AGS and RHIC to 65-70%.
Date: September 10, 2007
Creator: Zelenski,A.; Zelenski, A.; Kokhanovski, S.; Kponou, A.; Ritter, J. & Zubets, V.
Partner: UNT Libraries Government Documents Department
open access

The Effect of Extending the Length of the Coupling Coils in a MuonIonization Cooling Channel

Description: RF cavities are used to re-accelerate muons that have beencooled by absorbers that are in low beta regions of a muon ionizationcooling channel. A superconducting coupling magnet (or magnets) arearound or among the RF cavities of a muon ionization-cooling channel. Thefield from the magnet guides the muons so that they are kept within theiris of the RF cavities that are used to accelerate the muons. Thisreport compares the use of a single short coupling magnet with anextended coupling magnet that… more
Date: November 10, 2007
Creator: Green, Michael A.
Partner: UNT Libraries Government Documents Department
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