EIS and XPS studies on passive film of AISI 304 stainless steel in dilute sulfuric acid solution

Electrochemical impedance spectroscopy and XPS studies on AISI 304 stainless steel in naturally aerated 0.5 M H₂SO₄ solution were carried out at room temperature. The valuable model of the metal/solution interphase was established, and the reliable equivalent electrical circuits in the solution were presented. The analysis of the chemical composition of passive film on AISI 304 stainless steel was carried out by XPS. The passive film of AISI 304 stainless steel is composed of oxyhydroxides, Fe₂O_3, FeO, Cr₂O₃, NiO, sulfate, sulfite, and sulfide (FeS, NiS). It is reported that the ferrous sulfide film formed on AISI 304 stainless steel in the dilute sulfuric acid solution. The possible process in which sulfuric acid is reduced to sulfite and sulfide is proposed. The galvanic interaction of sulfide inclusions with the base alloy is introduced. Copyright © 2011 John Wiley & Sons, Ltd.     

Co2+,Er3+:Y3Al5O12晶体的生长及其吸收特性

应用中频感应提拉法成功生长出新型的Co2+,Er3+:Y3Al5O12晶体.研究了室温下晶体的吸收光谱性能.结合Er3+:Y3Al5O12晶体的光谱,并利用调Q判据对Co2+,Er3+:Y3Al5O12晶体调Q特性进行了简单的分析.结果表明Co2+,Er3+:YAG晶体是一种很有潜力的自调Q激光晶体.     

Hollow microspheres with covalent‐bonded colloidal and polymeric shell by Pickering emulsion polymerization

Hollow microspheres with SiO₂/polymer binary shell were fabricated from Pickering emulsion stabilized solely by methacryloxypropyltrimethoxysilane‐modified SiO₂ particles, and were characterized by optical microscopy, scanning electron microscopy, Fourier transformation infrared spectrum, thermogravimetric analysis (TGA), and energy dispersive X‐ray spectroscopy. The microspheres were templated by the Pickering droplets and the inner structure was affect by the proportion of crosslinking reagent. TGA result indicated that 60.3% of polymer in the shell was connected with SiO₂ by covalent bond which was formed by copolymerization of styrene and the reactive C?C group on SiO₂ stabilizer. Copyright © 2011 John Wiley & Sons, Ltd.     

离子交换法从醋酸溶液中提取脯氨酸的研究

本文研究了脯氨酸在732,DO01,DH-8三种阳离子交换树脂上的静态吸附特性,发现732树脂的吸附容量最大,速度最快。并选用732树脂,研究了它从醋酸脯氨酸水溶液中吸附脯氨酸的动态过程。最后,以氨水为洗脱剂,考察了不同氨水浓度,洗脱速度对洗脱过程的影响。     

微波消解样品-冷原子吸收光谱法测定鱼粉中微量汞

以微波溶样技术消解样品,采用正交试验设计优化冷原子吸收光谱法测定汞的试验条件,并对微波消解条件和共存离子的干扰进行了试验。试验表明：汞含量在30μg·L^-1范围内服从比耳定律,方法的检出限为0．13μg·L^-1,相对标准偏差为2．6％,回收率为97．6％～106．8％。     

Perturbation analysis for the positive definite solution of the nonlinear matrix equation X-\sum_{i=1}^{m} A_{i}^{*}X^{-1}A_{i}=Q

Consider the perturbation analysis for positive definite solution of the nonlinear matrix equation $X-\sum_{i=1}^{m}A_{i}^{*}X^{-1}A_{i}=Q$ which arises in an optimal interpolation problem. Two perturbation bounds for the unique positive definite solution are obtained, and an explicit expression of the condition number for the unique positive definite solution is derived. The theoretical results are illustrated by several numerical examples.     

Numerical methods for portfolio selection with bounded constraints

This work develops an approximation procedure for portfolio selection with bounded constraints. Based on the Markov chain approximation techniques, numerical procedures are constructed for the utility optimization task. Under simple conditions, the convergence of the approximation sequences to the wealth process and the optimal utility function is established. Numerical examples are provided to illustrate the performance of the algorithms.     

Insight into copper-catalyzed decarboxylative thiolation of carboxylic acids in the gas phase

Organocopper complexes bearing bidentate nitrogen ligands were synthesized in the gas phase by electrospray ionization mass spectrometry. Gas-phase decarboylative thiolation reaction was carried out in the ion-trap analyzer by collision-induced dissociation and ion-molecule reaction. The carboxylic acids were finally converted to thioethers as a neutral loss via collision-induced dissociation. During this process, copper acetate acted as a catalyst, and the valence state change of copper was observed. Meanwhile, the mechanism of decarboxylative thiolation was examined. This reaction was also suitable for different carboxylic acids and bidentate nitrogen ligands in the gas phase.     

高功率半导体激光器光纤耦合实验研究

为进一步提高光纤耦合半导体激光器的输出功率,提出了一种多单管半导体激光器通过台阶分布、光束精密准直及自由空间合束实现高功率光纤耦合输出的方法,该方法具有结构简单、光学元件易于加工、耦合效率高等优点。采用这种方法对5只封装在次热沉上的单管半导体激光器开展了芯径100 m、数值孔径0.22多模光纤的耦合实验研究,当工作电流为7.0 A时,光纤连续输出功率为21.8 W,亮度为1.83 MW/(cm2sr) ,耦合效率为70.32%。