Bound states of the Dirac equation with position-dependent mass for the Eckart potential

Studying with the asymptotic iteration method, we present approximate solutions of the Dirac equation for the Eckart potential in the case of position-dependent mass. The centrifugal term is approximated by an exponential form, and the relativistic energy spectrum and the normalized eigenfunctions are obtained explicitly.     

Effects of non-Gaussian noise on a calcium oscillation system

We investigate the effects of the non-Gaussian colored noise on a calcium oscillation system using stochastic simulation methods. It is found that the reciprocal coefficient of variance R has a maximum (R max ) with increasing noise intensity Q. The non-Gaussian noise parameter q has an important effect on the system. For some values of q (e.g., q = 0.9, q = 1.0), R has a maximum with increasing correlation time τ. Non-Gaussian noise induced spikes are more regular than Gaussian noise induced spikes when q is small and Q has large values. The R has a maximum with increasing q. Therefore, non-Gaussian noise could play more effective roles in the calcium oscillation system.     

神经网络与紫外光谱法同时测定芳香类化合物

测定了苯酚、苯胺、α萘胺、间二硝基苯及对氧基苯甲醛混合体系的紫外光谱，用神经网络法直接对混合体系紫外光谱数据进行处理，成功地测定了混合体系各组分含量，结果良好     

碳笼化合物的高效液相色谱研究

采用化学键合固定相（ＤＮＡＰ－ＳＰ）及二元混合流动相（５０％苯－正已烷），对碳笼化合物Ｃ６０与Ｃ７０的高效液相色谱（ＨＰＬＣ）分析及分离进行了研究。比较了多种流动相对Ｃ６０、Ｃ７０分离效果的影响，苯／正已烷混合体系是最好的流动相。     

Optical biosensors based on Prussian Blue films

Optical biosensing schemes based on enzymatically modified inorganic/organic transparent films predominately composed of Prussian Blue are demonstrated. The composite film, which is non-electrochemically deposited on a non-conducting support. is used as an optical transducer for flow-through biosensors based on hydrolases and oxidases. Urease and glucose oxidase are utilized as model enzymes. Action of the urea biosensor is based on optical pH sensitivity of Prussian Blue indicator. The glucose biosensor is acting as first-generation optical biosensor based on in situ generated Prussian White transducer for hydrogen peroxide. These simple, single-pass transmission optical biosensors exhibit sensitivity in the millimolar range of concentration. The biosensors are very stable owing to presence of a poly(pyrrolylbenzoic acid) network in the composite material. This organic polymer plays a dual role as a binding agent for inorganic material and as a functionalized support for strong covalent immobilization of enzyme molecules.     

Potentiometric study of end-point detection in the coulometric determination of carbon dioxide

The coulometric determination of carbon dioxide is based on the alkalimetric titration of the product of absorption of carbon dioxide in an organic solution of monoethanolamine. The processes occurring in various solvents have been investigated and optimized for analytical application. The protolytic reactions of 2-hydroxyethylcarbamic acid have been investigated in 2-propanol + 2, 5 and 10% water, dimethylformamide + 2% water, dimethylsulphoxide +5, 10 and 20% water. In coulometric generation of the base, 0.1M solutions of tetraethylammonium bromide in these solvents were used. The course of the titration was followed potentiometrically with glass and antimony indicator electrodes. From the titration curves the autoprotolysis constants of the mixed solvents and protonation constants of monoethanolamine in them were calculated. These constants and the concentration of monoethanolamine influence the size of the end-point break for the titrations. On this basis, optimal conditions for analysis have been selected and the total carbon content in samples of natural waters has been determined.     

Catalytic and Mechanistic Insights of the Low‐Temperature Selective Oxidation of Methane over Cu‐Promoted Fe‐ZSM‐5

The partial oxidation of methane to methanol presents one of the most challenging targets in catalysis. Although this is the focus of much research, until recently, approaches had proceeded at low catalytic rates (<10 h^?1), not resulted in a closed catalytic cycle, or were unable to produce methanol with a reasonable selectivity. Recent research has demonstrated, however, that a system composed of an iron‐ and copper‐containing zeolite is able to catalytically convert methane to methanol with turnover frequencies (TOFs) of over 14 000 h^?1 by using H₂O₂ as terminal oxidant. However, the precise roles of the catalyst and the full mechanistic cycle remain unclear. We hereby report a systematic study of the kinetic parameters and mechanistic features of the process, and present a reaction network consisting of the activation of methane, the formation of an activated hydroperoxy species, and the by‐production of hydroxyl radicals. The catalytic system in question results in a low‐energy methane activation route, and allows selective C₁‐oxidation to proceed under intrinsically mild reaction conditions.     

Plastic analysis of the crack problem in two-dimensional decagonal Al-Ni-Co quasicrystalline materials of point group 10,■

The fundamental plastic nature of the quasicrystalline materials remains an open problem due to its essential complicacy.By developing the proposed generalized cohesive force model,the plastic deformation of crack in point group 10,10 decagonal quasicrystals is analysed strictly and systematically.The crack tip opening displacement(CTOD) and the size of the plastic zone around the crack tip are determined exactly.The quantity of the crack tip opening displacement can be used as a parameter of nonlinear fracture mechanics of quasicrystalline material.In addition,the present work may provide a way for the plastic analysis of quasicrystals.     

对磺酰胺基苯基重氮氨基偶氮苯的合成及其与镉显色反应的研究

报道了新显色剂对磺酰胺基苯基重氮氨基偶氮苯的合成及其与镉的显色反应。在非离子表面剂活性剂 OP存在下 ,于 p H11.2 6的 NH4Cl- NH3 · H2 O缓冲溶液中 ,新试剂与镉生成 3∶ 1的稳定络合物 ,最大吸收波长在 5 10 nm处 ,表观摩尔吸光系数 ε=1.2 3× 10 5L·mol-1·cm-1。镉量在 0— 10 .6 7μg/ 2 5 m L范围内遵守比耳定律。本法用于测定工业废水中微量镉 ,结果令人满意