Open charm yields in d+Au collisions at squareroot[sNN]=200 GeV

Midrapidity open charm spectra from direct reconstruction of D0(D0)-->K-/+pi+/- in d+Au collisions and indirect electron-positron measurements via charm semileptonic decays in p+p and d+Au collisions at squareroot[sNN]=200 GeV are reported. The D0(D0) spectrum covers a transverse momentum (pT) range of 0.1相似文献   

Space charge analysis in enamelled wires by using thermally stimulated depolarization current (TSDC)

This paper reports on measurements of thermally stimulated depolarization current (TSDC) that is applied to characterize changes in the large motors and generators enamelled wires that have been exposed to aging under steep-front pulse voltage waveforms. The thermoelectrets are prepared at various polarizing fields, E_P, and measurements of TSDC are carried out both as a function of time and temperature over the range of 23–200 °C. In addition, various TSDC parameters such as activation energy, ?_a, characteristic relaxation time, τ and the released charge, Q during the relaxation process have been determined by applying initial rise method. The experimental results for TSDC spectra of wire specimens have shown that the total stored charge in the insulation bulk increases significantly, as the number of insulation layers increases on the wire. The reason for such a higher concentration of trapped charges is more likely due to the presence of a broad distribution of the traps, which are occupied by the injected charges.     

Identified hadron compositions in p+p and Au+Au collisions at high transverse momenta at √S(NN)=200 GeV

We report transverse momentum (p(T)≤15 GeV/c) spectra of π(±), K(±), p, p[over ˉ], K(S)(0), and ρ(0) at midrapidity in p+p and Au+Au collisions at √S(NN)=200 GeV. Perturbative QCD calculations are consistent with π(±) spectra in p+p collisions but do not reproduce K and p(p[over ˉ]) spectra. The observed decreasing antiparticle-to-particle ratios with increasing p(T) provide experimental evidence for varying quark and gluon jet contributions to high-p(T) hadron yields. The relative hadron abundances in Au+Au at p(T)?8 GeV/c are measured to be similar to the p+p results, despite the expected Casimir effect for parton energy loss.     

Measurement of the bottom quark contribution to nonphotonic electron production in p + p collisions at √s=200 GeV

The contribution of B meson decays to nonphotonic electrons, which are mainly produced by the semileptonic decays of heavy-flavor mesons, in p + p collisions at √s=200 GeV has been measured using azimuthal correlations between nonphotonic electrons and hadrons. The extracted B decay contribution is approximately 50% at a transverse momentum of pT≥5 GeV/c. These measurements constrain the nuclear modification factor for electrons from B and D meson decays. The result indicates that B meson production in heavy ion collisions is also suppressed at high pT.     

Protein dynamics and function: Making new strides with an old warhorse,the alkaline conformational transition of cytochrome c

Protein dynamics is intimately linked to function. In metalloproteins, dynamics are often coupled to redox activity, ligand binding and enzyme function. We provide a concise overview of the field and then focus on the use of the alkaline conformer of cytochrome c as a model system to probe the factors that control the conformational dynamics of proteins in general and metalloproteins in particular. We consider the effects of ligands on metal-mediated dynamics, the interplay between intrinsic metal-ligand dynamics and barriers imposed by the protein scaffold itself, and the effects of local and overall protein stability on dynamics. Discussed within are the collected results from equilibrium thermodynamic methods, pH jump kinetics and conformationally gated redox reactions between small inorganic reagents and metalloproteins used as a means to probe conformational switching in metalloproteins.     

Quaternionic Kähler Detour Complexes and $${\mathcal{N} = 2}$$ Supersymmetric Black Holes

We study a class of supersymmetric spinning particle models derived from the radial quantization of stationary, spherically symmetric black holes of four dimensional \({{\mathcal N} = 2}\) supergravities. By virtue of the c-map, these spinning particles move in quaternionic Kähler manifolds. Their spinning degrees of freedom describe mini-superspace-reduced supergravity fermions. We quantize these models using BRST detour complex technology. The construction of a nilpotent BRST charge is achieved by using local (worldline) supersymmetry ghosts to generate special holonomy transformations. (An interesting byproduct of the construction is a novel Dirac operator on the superghost extended Hilbert space.) The resulting quantized models are gauge invariant field theories with fields equaling sections of special quaternionic vector bundles. They underly and generalize the quaternionic version of Dolbeault cohomology discovered by Baston. In fact, Baston’s complex is related to the BPS sector of the models we write down. Our results rely on a calculus of operators on quaternionic Kähler manifolds that follows from BRST machinery, and although directly motivated by black hole physics, can be broadly applied to any model relying on quaternionic geometry.     

Anisotropically Polarizable Dispersions. Basic Thermodynamic Equations and Kinetic Coefficients

Dispersion media formed by anisotropically polarizable particles suspended in nonconducting viscous fluid are considered. The particle anisotropy is set by a freezing-in unit vector; the particle shape is assumed to be close to spherical. A complete hydrodynamic model of such a medium is constructed. The expression for the free energy of a system is derived, and the laws governing the polarization of a dispersion medium and the relaxation of its anisotropy are revealed. The dependence of the effective viscosity of dispersion medium on the strength of an electric field during the flow in plane capillaries is determined.__________Translated from Kolloidnyi Zhurnal, Vol. 67, No. 3, 2005, pp. 293–298.Original Russian Text Copyright © 2005 by Vasil’eva, Cherney.     

Calculation of leakage current density of silicone rubber insulators under accelerated aging conditions

The paper presents two different methods to calculate the current density along silicone rubber (SiR) insulator surface under salt-fog testing conditions. The first method which is based on field theory approach uses the commercial software COMSOL^® to compute the current density. The conductivity of the contamination layer used in the calculations was extracted from the measured equivalent salt deposit density (ESDD) separately for different regions of the insulator surfaces. The second method is based on circuit theory approach. The insulator surface was divided into different sections for resistance calculations to account for different contamination levels. Rankings based on the calculated current densities based on segmentation of the insulator surface for ESDD measurements match with those extracted from measured leakage currents.     

Diffusion Studies on Polystyrene in 1,4-Dioxane

The diffusion behavior of polystyrene with narrow molecular weight distribution at 20℃ in 1, 4-dioxane was investigated by the photon correlation spectroscopy. The cumulant method was employed for the analysis of the intensity-intensity autocorrelation function measured over a wide range of the scattering vector. The diffusion coefficient D was determined as the function of concentration C in the molecular weight range of 3. 0×104-1. 20×106. In a low concentration range, D was found to be linearly dependent on C, which has been found for some other systems. The dependence of D on molecular weight at infinite dilution can be written as an empirical formula D0 = kDM-γ M, the exponent γ(0. 576 ±0. 01) is in good agreement with the result of the scaling theory.