周边固支圆板非线性热弹耦合振动分析

导出了轴对称圆板非线性热弹耦合自由振动基本方程,对周边固支圆板运用伽辽金法求解,得出振幅随时间变化的数值解.将热弹耦合与非热弹耦合情况进行对比,发现振幅较小时,热弹耦合效应使板的固有频率相对于无热弹耦合情形提高;振幅较大时,热弹耦合效应使固有频率降低.最后比较了不同热弹耦合参数对应的振动情况.     

阴离子X~-(F~-、Cl~-、Br~-)对中孔分子筛MCM-41合成与性质的影响

在凝胶体系ＮａＸ（Ｆ、Ｃｌ、Ｂｒ）Ｎａ２ＯＡｌ２Ｏ３ＳｉＯ２ＣＴＡＢ（十六烷基三甲基溴化铵）Ｈ２Ｏ中，研究了水热合成中孔ＭＣＭ４１的合成条件。实验证明，在３９８Ｋ下晶化８～１６ｄ，ＮａＸ／ＳｉＯ２介于０．０１～０．０５时，均可合成出ＭＣＭ４１分子筛；ＮａＦ的加入，可以加快ＭＣＭ４１分子筛的晶化速度；ＮａＢｒ的加入，对形成ＭＣＭ４１分子筛有阻碍作用。采用ＸＲＤ、ＳＥＭ、ＴＧＤＴＡ和Ｎ２吸附对合成样品加以表征，证明合成样品具有介孔分子筛特性。     

A new isoelectric focusing system for fast two-dimensional gel electrophoresis using a low-concentration polyacrylamide gel supported by a loose multifilament string.

A new isoelectric focusing (IEF) system for two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) has been proposed. In this system, a super-soft and tough IEF gel was achieved by casting polyacrylamide gel down to 2.0% T using a loose multifilament string (LMS) of nylon as a gel support. The IEF apparatus for the LMS-gel, fabricated from acrylic boards, had a cooling water chamber, and eliminated the need of electrode solutions by directly connecting the two ends of individual gels to platinum electrodes. The carrier ampholyte-generated pH gradients using the new IEF system was stable over a long duration of time and a wide range of voltages, and the IEF time became shorter using a 2.0% T gel than using a 4.0% T gel. Also, the LMS-gels prepared in different runs exhibited excellent reproducibility. The new IEF system was applied to 2-D PAGE of a chicken skeletal muscle extract, and it was found that the protein loading capacity, protein entry into the LMS-gels, and protein transfer efficiency from the first-dimensional to the second-dimensional gels were significantly improved by using a low-concentration (2.5% T) gel. Also, proteins of high molecular weight of more than 200 kDa were observed in the 2-D maps, and therefore the new IEF system has a very good potential to be applied for fast 2-D PAGE of high molecular-weight proteins.     

500微米沸石分子筛单晶的制备方法

介绍了20世纪如年代以来500μg以上的沸石分子筛单晶的六种制备方法，包括类区域融化法、植入晶种法、有机热合成法、块状原料溶解法、氟离子效应合成法和双硅源法。这些方法通过控制反应体系中晶核的形成数量，然后在这些极少数晶核的基础上培养出沸石分子筛大单晶。     

ZnI2‐promoted homologation of ferrocenylacetylene and aldehydes: an efficient synthesis of ferrocene‐containing allenes

A concise and efficient protocol for the first synthesis of ferrocene‐containing allenes based on the homologation reaction of ferrocenylacetylene and aldehydes promoted by ZnI₂ was developed. The present method was applicable to many kinds of substituted aldehydes, providing good to excellent yields of ferrocene‐containing allenes. Copyright © 2012 John Wiley & Sons, Ltd.     

Determination of ultratrace lead with bismuth film electrodes based on magneto-voltammetry

A novel method for the determination of Pb²⁺ with bismuth film electrodes (BFEs) based on magneto-voltammetry was investigated. In the presence of a 0.6?T external magnetic field, square wave voltammetry of Pb²⁺ was performed with BFEs. A high concentration of Fe³⁺ was added to the analytes to generate a large cathodic current during the preconcentration step. A Lorentz force from the flux of net current through the magnetic field resulted in convection. Then, more Pb²⁺ deposited onto the electrode and larger stripping peak currents were observed. BFEs that were prepared by simultaneously depositing the bismuth and Pb²⁺ on an electrode offered a mercury-free environment for this determination. This method exhibits a high sensitivity of 4.61?µA?µM^?1 for Pb²⁺ over the 1?×?10^?8 to 1?×?10^?6?M range. A detection limit as low as 8.5?×?10^?10?M was obtained with only 1-min preconcentration. The method was successfully applied to determine Pb²⁺ in real water samples.     

Silica‐particle‐supported zwitterionic polymer monolith for microcolumn liquid chromatography

A silica‐particle‐supported zwitterionic polymeric monolithic column, shortened as supported column (S‐column), was prepared by the in situ polymerization of methacrylic acid, ethylene dimethacrylate, and 2‐(dimethylamino)ethyl methacrylate in the presence of a ternary porogenic solvent containing water, methanol, and cyclohexanol in a 250 μm id fused‐silica capillary prepacked with 5 μm bare silica particles. In the S‐column, a thin layer of the polymers was formed around the silica particles in the form of nanoglobules, leaving the interstitial spaces between the particles free for liquid flow. The effects of the preparation conditions on the morphology of the monolith were investigated by scanning electron microscopy and backpressure measurements. The selected volumetric ratio of porogens, monomer concentration, polymerization time, and temperature are 1:1:8 (water/methanol/cyclohexanol), 25% v/v, 5 h, and 60°C, respectively. The S‐column was evaluated by comparison with its conventional organic counterpart in terms of morphology, mechanical stability, permeability, swelling–shrinking behavior, capacity, and efficiency. The results demonstrate that the S‐column is superior to its counterpart in all the terms with the exception of permeability. The above merits and zwitterionic property of the S‐column were further confirmed by separate separations of four inorganic anions and three organic cations.     

多目标跟踪

本文论述了多目标光电跟踪探测技术发展概况,包括跟踪算法及光电传感设备,并讨论了将来的发展趋势.     

氮杂碳原位包覆Cu2O/Co3O4@C异质结构复合材料的设计构筑及高效储锂性能

通过液相法合成了Cu₂O纳米立方体, 并在其基础上利用金属有机框架化合物(MOFs)的自组装形貌调控, 进一步构建了层级多孔Co₃O₄和氮杂碳双壳层的Cu₂O/Co₃O₄@C异质结构复合材料. 利用X射线衍射(XRD)、 扫描电子显微镜(SEM)、 透射电子显微镜(TEM)、 热重分析(TGA)、 BET比表面积及孔径分析、 拉曼光谱和X射线光电子能谱(XPS)等表征手段证实了Cu₂O/Co₃O₄@C异质结构复合材料的成功构筑. 双壳层结构设计和丰富的层级孔道结构有效抑制了材料在充放电循环过程中的体积膨胀, 材料在循环100次后仍保持了原有的形貌和构造. 表面多孔结构对电解液的充分浸润、 异质结构的界面内建电场以及缺陷氮杂碳的表面包覆有效提升了材料的电子和离子导电能力. 异质结构设计、 形貌调控、 多孔特性和氮杂碳的协同作用, 使得Cu₂O/Co₃O₄@C复合材料呈现出优异的电化学性能, 在0.1 A/g电流密度下的首次放电比容量达到2065 mA·h/g, 在 2 A/g电流密度下的可逆放电比容量高于360 mA·h/g, 在1 A/g电流密度下循环350次后仍有530 mA·h/g的高可逆放电比容量.