Liquid phase oxidation of p-chlorotoluene to p-chlorobenzaldehyde over cobalt-doped mesoporous titania with a crystalline framework

Cobalt-doped mesoporous titania with a crystalline framework synthesized by surfactant templating method presented highly selective (99%) and reasonable conversion rate (49%) of catalytic oxidation of para-chlorotoluene to para-chlorobenzaldehyde in acetic acid using aqueous hydrogen peroxide as oxidant for the first time. Recycling of the catalyst indicates that the catalyst can be used a number of times without losing its activity to a greater extent. By contrast, cobalt-doped mesoporous titania without a crystalline structure and cobalt doped the commercial titania, Degussa P25 prepared by impregnation method with the similar concentration of cobalt were found inactive. The effects of catalyst concentration, reaction time, reaction temperature, and solvents on the performance of the catalyst were also investigated.     

On Polynomial Functions over Finite Commutative Rings

Let R be an arbitrary finite commutative local ring. In this paper, we obtain a necessary and sufficient condition for a function over R to be a polynomial function. Before this paper, necessary and sufficient conditions for a function to be a polynomial function over some special finite commutative local rings were obtained.     

非均匀散射层矢量辐射传输(VRT)方程高阶散射解的迭代法

将散射介质层在z轴方向划分成薄层，用薄层的一阶散射强度、Fourier变换和迭代方法求解散射介质整层的矢量辐射传输(VRT)方程的高阶散射解.该方法将一阶散射与高阶散射迭代结合起来，计算公式简明，可计算高阶迭代解，计算时间少.计算结果与一层均匀散射介质的VRT方程一阶Mueller矩阵解、半空间均匀散射介质二阶Mueller矩阵解、以及离散坐标-特征值特征矢量法的VRT热辐射的数值解作了全面的比较.提出并讨论了非均匀散射层主动与被动VRT方程的高阶解.本计算程序可以通用于非球形粒子多层结构及非均匀介质的散射和热辐射计算. 关键词： VRT方程 分层 迭代解     

每个算子都是两个强不可约算子的和

本文证明了可分无穷维 Hilbert空间上每个有界线性算子均可写成两个强不可约算子之和 .这回答了文献 [9]中提出一个公开问题     

The Synthesis of Glycoglycerolipids

A convenient synthetic route was developed for the synthesis of the novel glycolipids: 1,2-di-O-acyl-3-O-(2‘-acylamide-2‘-denxy-ct-D-glucopyranosyl)-sn-glycerols. 10 new compounds of glycolipids with different acyl groups were obtained.     

Second order parabolic equations in Banach spaces with dynamic boundary conditions

In this paper, we exhibit a unified treatment of the mixed initial boundary value problem for second order (in time) parabolic linear differential equations in Banach spaces, whose boundary conditions are of a dynamical nature. Results regarding existence, uniqueness, continuous dependence (on initial data) and regularity of classical and strict solutions are established. Moreover, several examples are given as samples for possible applications.

     

风冷热泵冷热水机组动态过程仿真

本文给出了风冷热泵冷热水机组动态过程模型。系统的高、低压段被分成制冷剂侧、管壁、以及水或空气侧三个控制容积。针对每个控制容积建立了质量和能量平衡的微分方程。由于压缩机、热力膨胀阀阀体、以及四通换向阀具有较小的热惯性,因而采用稳态模型描述压缩过程、膨胀过程、以及内泄露过程。膨胀阀感温包中的制冷剂温度对于蒸发器出口温度的延迟用一阶惯性环节来描述。通过“预测-校正”和“自适应步长”方法实现系统仿真。仿真结果与测试数据吻合良好。     

Si微电阻桥温度分布与热传导特性的显微Raman光谱研究

采用显微Raman光谱方法对红外目标模拟器中重掺杂Si微电阻桥单元的热传导特性进行研究，根据Si桥的实际特性建立相应的Raman散射模型，通过测量Raman峰位的移动得到高功率激光辐照下测量点的温度.对Si桥桥面分别进行了沿某些特殊线段的逐点线扫描和覆盖全部桥面的面扫描，得到各点的温升及其分布.用基于有限元分析的软件结合Si桥结构参数对各测量点的温升进行了模拟计算，其结果在热导分布的基本趋势上与实验相一致.实验细致地揭示了热导分布的局域起伏，反映出实际器件的不均匀性，为改进器件设计、优化器件性能提供了实验依据. 关键词： Raman光谱 Si桥 温度分布 热导     

Speciation Analysis of Inorganic Tin (Sn(II)/Sn(IV)) by Graphite Furnace Atomic Absorption Spectrometry Following Ion-Exchange Separation

A new method based on anion exchange resin separation and graphite furnace atomic absorption spectrometry (GFAAS) detection is proposed for the determination of inorganic tin species. The result showed that Sn(IV) was quantitatively retained on the resin when [HCl] = 9.0 mol · L⁻¹, but Sn(II) could not be adsorbed on the resin under the same condition. Thus, a separation of Sn(II) and Sn(IV) has been realized. When the concentration of NaOH solution was between 2.0–7.0 mol · L⁻¹, Sn(IV) that adsorbed on the resin could be eluated from the resin completely. Meanwhile, under the atmosphere and the nitrogen states, the translation between Sn(II) and Sn(IV) was investigated. Under the optimal conditions, the detection limit of Sn(IV) is 0.40 μg · L⁻¹ with RSD of 2.3% (n = 5, c = 2.0 μg · L⁻¹). The proposed method was applied to the speciation analysis of tin in different water samples and the recovery of total Sn was in the range of 98.7–101.7%. In order to verify the accuracy of the method, a certified reference water sample was analyzed and the results obtained were in good agreement with the certified value.