Strange-quark contributions to parity-violating asymmetries in the forward g0 electron-proton scattering experiment

We have measured parity-violating asymmetries in elastic electron-proton scattering over the range of momentum transfers 0.12 < or =Q2 < or =1.0 GeV2. These asymmetries, arising from interference of the electromagnetic and neutral weak interactions, are sensitive to strange-quark contributions to the currents of the proton. The measurements were made at Jefferson Laboratory using a toroidal spectrometer to detect the recoiling protons from a liquid hydrogen target. The results indicate nonzero, Q2 dependent, strange-quark contributions and provide new information beyond that obtained in previous experiments.     

ESR studies of Cu2+ doped in SrC4H4O6·3H2O single crystals

Electron spin resonance spectra of Cu²⁺ doped in single crystals of strontium tartrate trihydrate grown by a diffusion technique have been investigated at 77K. Copper enters the lattice substitutionally and is trapped at two magnetically inequivalent sites. ESR measurements gave the following values for the spin-Hamiltonian parameters. Cu²⁺(I): g_gg = 2.0380, g_yy = 2.1317, g_zz = 2.3918 and A_xx = 26.3 G, A_yy = 56.3 G, A_zz = 110.8 G. Cu²⁺(II): g_xx = 2.0497, g_yy = 2.1297, g_zz = 2.3706 and A_xx = 19.2 G, A_yy = 61.4 G, A_zz = 107.2 G.     

Influence of Doping Different Rare Earth Ions on the Luminescence of CaTiO3‐based Phosphors

This paper reports the Gd³⁺, Dy³⁺, Tb³⁺ and Lu³⁺ doped CaTiO₃ based phosphors were synthesized by modified solid‐state reaction method and its crystal structure and luminescent properties were investigated. The X‐ray diffraction patterns (XRD) showed that the phosphors sintered at 1000 °C for 2 h were a pure CaTiO₃ phases. The optimization of reaction conditions were carried out by thermal gravimetry and differential thermal analysis methods (DTA/TG). Surface and elemental analyses were performed by using on SEM instrument. The excitation and emission spectras were recorded by photoluminescence spectrophotometer (PL).     

Synthesis and phosphorescence properties of Dy3+ and (Pr3+–Dy3+) in MgTiO3

Using tetra-n-butyl titanate and magnesium nitrate as raw materials, Dy³⁺ and Pr³⁺ ions in the matrix of magnesium titanate (MgTiO₃) was successfully synthesized by a modified solid-state reaction. The mixtures to achieve a solid-state reaction were heated in porcelain crucibles at 600?°C for 2?h, 900?°C for 6?h, and 1000.0?°C for 2?h. The reaction products obtained in an air atmosphere were characterized by X-ray powder diffractions. The optimization of reaction conditions were carried out by thermal gravimetry and differential thermal analysis methods. Surface and elemental analyses were performed by using on SEM instrument. The excitation and emission spectra were recorded by photoluminescence spectrophotometer.     

Facilitated Transport of Cr(VI) through Polymer Inclusion Membrane System Containing Calix[4]arene Derivative as Carrier Agent

Chromium(VI) is one of the major toxic elements present in environmental samples. The polymer inclusion membrane (PIM), has been developed to provide metal ion transport with high selectivity. This study was conducted to discover efficient methods for removing Cr(VI) from wastewater. A functionalized calix[4]arene carrier 1 in a PIM system was used to transport Cr(VI) from an acidic aqueous donor phase solution to an acceptor phase that contained an acetic acid/ammonium acetate solution at pH 6. The prepared PIM was characterized with Fourier Transform Infrared (FT-IR) spectroscopy and the Atomic Force Microscopy (AFM) techniques as well as with contact angle measurements. The efficiency of Cr(VI) transport through the PIM was investigated by studying the effects of carrier concentration on the membrane phase as well as by measuring the amount of plasticizer in the membrane, the pH in the acceptor phase and the membrane's stability and thickness. The kinetic parameters were calculated as rate constant (k), permeability coefficient (P), flux (J) and diffusion coefficient (D_o). The transport efficiency of Cr(VI) was observed to be 98.61% after 10 h under optimized conditions. The experimental results show that Cr(VI) can transport from the donor phase to the acceptor phase with high efficiency through the PIM. The results also suggest that the transport efficiency of the PIM was reproducible and that a PIM is effective for long-term separation processes.     

ESR study of ascorbic acid irradiated with gamma-rays

The interest in application of high-energy ionizing radiation for stenlization of pharmaceutical products and foodstuffs has led a number of workers to investigate the radiation sensitivity of vitamins. Aside from its use as a vitamin, ascorbic acid (AA) or some derivatives are employed as antioxidants in foodstuffs. The effects of ionizing radiation on AA in simple solutions and in mixture of naturally occurring compounds have been extensively reported in the literature. However, the effects of ionizing radiation on solid AA were reported in few works which described rather dosimetric features of AA No reports, except one, are available describing the characteristic features of the radiolytic intermediates produced after irradiation of polycrystalline AA. Irradiation studies performed on single crystal of AA has led us to reinvestigate our previous work on the radiolytic intermediates produced in irradiated polycrystalline AA. Three radical species, rather than two, having different characteristics were decided contributing to the formation of experimental electron spin resonance (ESR) spectrum of γ-irradiated polycrystalline AA. Spectral parameters of these species were calculated after exhaustive spectrum simulation calculations based on data derived from experimental microwave saturation and dose-response studies.     

Design of polarization-maintaining retro-reflector for folded-path applications

A design of polarization-maintaining retro-reflectors(PMRRs) for folded-path applications is proposed and analyzed.The prism-based scheme enables the output light,which is parallel to the input,to have an identical state of polarization.The principle of the design is theoretically verified,and the related error is analyzed due to possible manufacturing imperfection.The maximum spatial angle error is ±2.75°.The effect on the extinction ratio and insertion loss is also discussed,which further proves the design’s feasibility in practical applications.     

关于n+k相多体系(k≥4)封闭网的构造

本文证明了n+k多体系(k≥4)的全部可能的封闭网均可以通过若干相应的子n+3相多体系的拼合运算得出,从而为具体构造n+k相多体系(k≥4)的全部合理的封闭网,提供了基本方法。     

超导临界温度理论(Ⅱ)

在文献[1]中,我们导出了超导临界温度T-c的一个严格级数表式.本文讨论这个级数的收敛范围,以及通过解析延拓来扩展收敛范围的可能性.结论是:我们的T_c级数(指文献[1]原来的级数,或者经过延拓后的级数)在∞>λ>λ₀的整个范围内,都是收敛的.这里λ₀是Matsubara表象中使决定T_c的方程具有正实数解的最小的λ值.它实际上就是库伦赝势.因此,也许除了少数非常弱耦合的超导体以外,我们的T_c级数能适用于一切超导体.