Study of radiation background at the north crossing point of the BEPCⅡ in collision mode

Understanding the radiation background at the north crossing point (NCP) in the tunnel of BEPCII is crucial for the performance safety of the High Purity Germanium (HPGe) detector, and in turn of great significance for long-term stable running of the energy measurement system. Therefore, as the first step, a NaI(Tl) detector is constructed to continuously measure the radiation level of photons as background for future experiments. Furthermore, gamma and neutron dosimeters are utilized to explore the radiation distribution in the vicinity of the NCP where the HPGe detector will be located. Synthesizing all obtained information, the shielding for neutron irradiation is studied based on model-dependent theoretical analysis.     

GISAXS and SAXS studies on the spatial structures of Co nanowire arrays

The spatial structures of magnetic Co nanowire array embedded in anodic aluminium membranes were investigated by grazing incidence small angle X-ray scattering (GISAXS) and conventional small angle X-ray scattering (SAXS) techniques. Compared with SEM observation, the GISAXS and SAXS measurements can get more overall structural information in a large-area scale. In this study, the two-dimensional GISAXS pattern was well reconstructed by using the IsGISAXS program. The results demonstrate that the hexagonal lattice formed by the Co nanowires is distorted (a ≈ 105 nm, b ≈ 95 nm). These Co nanowires are isolated into many structure domains with different orientations with a size of about 2 μm. The SAXS results have also confirmed that the nanopore structures in the AAM can be retained after depositing Co nanowires although the Co nanowires can not completely but only just fill up the nanopores. These results are helpful for understanding the global structure of the Co nanowire array.     

Fast computation of observed cross section for ψ′ → PP decays

It has been conjectured that the relative phase between strong and electromagnetic amplitudes is universally -90° in charmonium decays. ψ′ decaying into a pseudoscalar pair provides a possibility to test this conjecture. However, the experimentally observed cross section for such a process is depicted by the two-fold integral, which takes into account the initial state radiative (ISR) correction and energy spread effect. Using the generalized linear regression approach, a complex energy-dependent factor is ...     

A New Capillary Electrophoresis Apparatus with Piezoelectric Ceramics High Voltage Source and Amperometric Detector

IntroductionHighperformancecapiliar}'electrophoresis(HPCE)isanewanalyticaltechnology'rapidly'developedinrecentyears.Withtheadvantagesofsmallsample.highsensitivity,highresolution.rapidanalysisandverycheaprunning,ithasbeenappliedinchemistry'.lifescienc...     

A new theory for symmetry orbital and tensor (Ⅱ)——Symmetric reduction of molecular integrals and self-consistent field calculations

The symmetry orbital-symmetry orbital tensor method is applied to the evaluation of molecular integrals (one-electron and two-electron integrals) and the symmetry-orbital-tensor and self-consistent-field (SOT-SCF) calculations. A calculation scheme is proposed to simplify the evaluation of integrals and a key equation is derived to reduce the computation efforts in SCF iterations. According to the key equation, compared with the traditional SCF method, the computation efficiencies including CPU timing and external disk (or internal memory) requirement increase in the magnitude of the square of the order of a point group. The new SOT method is expected to be useful in the theoretical calculations of large molecular systems of high point group symmetries.     

ITO靶材黑化物的X射线光电子能谱研究

利用X射线光电子能谱（XPS）分析了ITO靶材黑化物的化学组成，结果表明黑化物由In、Sn、O和C组成，相对原子百分含量In为34．35％，Sn为2．74％，O为52．65％，C为10．26％；In、Sn处于亚氧化状态；C有部分氧化。与原始靶材相比，黑化物的元素组成和化学状态发生了明显的变化。择优溅射最可能引起成分比例失常，真空残余的合C气体和泵油蒸汽被认为是污染C的直接来源。     

THEORY AND APPLICATIONS OF FREQUENCYMETRIC TITRATION

Theory on frequencymetric titration has been proposed based on equivalent circuit of piezoelectric quartz crystal (PQC) in liquid and oscillation equation of TTL-PQC oscillator, and the theoretical equation derived representing the frequency shift with respect to the solution conductivity. Practical examples of various types of titration are given in this paper.     

固-液系统中表面增强喇曼散射强度ISERS对浓度c的依赖关系及水杨酸分子的吸附等温特性研究

在恒定温度下,通过测量不同浓度溶液中吸附在Ag镜表面水杨酸分子(SA)的表面增强喇曼散射(SEKS)强度(I_SERS,对固-液系统中吸附在Ag镜表面上SA分子的I_SERS对溶液浓度的依赖关系进行实验研究,并对I_SERS与吸附分子数N^s的关系进行分析讨论。实验研究和理论分析的结果表明:利用SERS技术通过测量I_SERS与溶液浓度c的依赖关系,可为固-液系统中分子在固体表面的吸附过程及吸附特性研究提供 关键词：     

石墨炉原子吸收测定血和尿中锰

本文研究了用硝酸镁作为基体改进剂，石墨炉原子吸收法直接测定全血和尿血锰。方法简单，准确，快速。     

HIV病毒传播的动力学研究的同伦映射解法

研究了艾滋病病毒的传播的一个动力学模型．利用同伦映射理论和方法得到了HIV流行性传染病区域的人群传播规律．