The dependence of polymer conductivity on the work function of metallic electrodes

It is shown that the occurrence of metallic conductivity in polymers is due to their electrification. In particular, the current density depends on the electron work function of metallic electrodes which are in contact with the polymer.     

分光光度法测定蒙药中痕量铅

采用双硫腙显色分光光度法测定蒙药中痕量铅,该方法具有简单、快速、灵敏等特点,用以测定蒙药中的痕量铅,获得了满意的结果.该方法线性范围为0.00-0.40μg/mL Pb2 ,相关系数0.9993.回收率95%-ll0%.     

航空胶片冲洗机直流电机调速控制系统设计

针对航空胶片冲洗机控制困难表现其电机负载不均匀，低速运行情况下电机震动剧烈．研制了专用的反馈控制系统．以双89C51单片机为核心组成控制电路，编写了系统操作程序和数字PID控制程序．对PID参量对控制系统稳定性的影响进行了分析，得出适应于本系统的PID控制规律，并经过大量的试验，获得了能使各档速度稳定运行下的PID控制参量．实践表明，该控制系统运行稳定可靠，低速控制准确度在3％以内，中高速准确度达到1％．     

Structure of the Products of Stimulated Carbonization of Aromatic Hydrocarbons

This paper deals with X-ray photoelectron and electron microscopy studies of the structure of carbon–metal-containing micro- and nanotubulenes. Ab initio quantum-chemical calculations were performed to analyze the possibility and mechanism of tubulene formation.     

非线性抛物型偏积分微分方程的H1-Galerkin 混合有限元方法

收稿给出一类非线性抛物型偏积分微分方程的H1-Galerkin混合有限元方法.给出了一维空间的半离散、全离散格式及最优阶误差估计,并将该方法推广到二维和三维空间.     

Multicapillary columns with a porous layer based on the divinylbenzene copolymer

A method for preparing a multicapillary column with a porous layer based on the styrene-divinylbenzene copolymer has been developed. The column makes it possible to quickly separate C₁–C₄ hydrocarbons and oxygen-containing compounds. The main chromatographic properties of the columns were studied.     

Conditions for the formation of copper nanoparticles by reduction of copper(II) ions with hydrazine hydrate solutions

Optimal conditions were found for the preparation of copper nanoparticles in aqueous solution via reduction of copper(II) ions with hydrazine hydrate. The effects of ligand environment of copper(II) in the initial solution (hydrate, ammonia, citrate, and glycine complexes), concentration, pH, surfactants, temperature, and mode of heating were examined. The obtained colloidal systems were studied by optical spectroscopy, X-ray photoelectron spectroscopy, X-ray powder diffraction, and atomic force microscopy. The examined colloids were found to contain generally spherical copper nanoparticles with a diameter of about 10 nm, which were coated with a copper(I) or copper(II) oxide and hydroxide film.     

Sparse asymptotic minimum variance based bearing estimation algorithm for a single vector hydrophone

For underwater target detection using a single vector hydrophone, sparse asymptotic minimum variance(SAMV) method is used to estimate the target bearing. The SAMV discretizes the entire scanning space and the target bearing is located at the position of the discrete direction. The SAMV algorithm utilizes the sparsity of the spatial signal to improve the estimation performance of the target bearing. Background noise level(BNL) of the bearing estimation of SAMV algorithm is lower than those of the conventional beam forming(CBF)method and minimum variance distortionless response(MVDR) method for different signal noise ratios(SNRs). When the SNR is higher than 0 d B, the direction-finding error of this algorithm is less than 2°. Moreover, the SAMV algorithm has a better dimensional orientation resolution capability. The experimental results show that the SAMV algorithm gives a bearing and time recording map with a lower BNL, which effectively verifies the effectiveness of SAMV algorithm in terms of underwater target detection.     

Investigation of structure and properties of divinylbenzene-styrene copolymer films

A method for preparation of divinylbenzene-styrene copolymer porous layer on the inner wall of a fused silica capillary was developed. Capillary gas chromatography was used to investigate the sorption capacity of copolymer film toward substances of various classes.