Tricyanometalate molecular chemistry: A type of versatile building blocks for the construction of cyano-bridged molecular architectures

Cyano-bridged molecule-based magnetic materials with reduced dimensionality, such as single-molecule magnets (SMMs) and single-chain magnets (SCMs), have attracted great research interest during the last decade. Among the cyano-based molecular precursors with ample coordinating capability, we note the ability of the tricyanometalate to link various metal ions lead to a wide diversity of structural architectures ranging from discrete polynuclear complexes to various one-dimensional (1D) assemblies. Some of them are promising cyano-bridged SMMs and SCMs. The use of capping tridentate organic ligands results in a number of clusters containing di-, tri-, tetra-, penta-, hexa-, octa-, fourteen-nuclear and various 1D metal-cyanide molecular architectures. Here we review the structural topologies of these complexes and their related magnetic properties, highlight typical examples, and point out the main possible directions that remain to be developed in this field. From the crystal engineering point of view, the compounds reviewed here should provide useful information for further design and investigation on this elusive class of cyano-bridged SMMs and SCMs.     

Morphology and optical absorption of Bi2Fe4O9 crystals via mineralizer-assisted hydrothermal synthesis

Submicron-sized Bi₂Fe₄O₉ crystals were successfully synthesized via the hydrothermal method, while micron-sized Bi₂Fe₄O₉ crystals with rod-like morphologies were obtained in the presence of the mineralizer KNO₃. X-ray diffraction, scanning electron microscopy and transmission electron microscopy were employed to characterize the products. According to a series of time-dependent experiments, it was concluded that the likeliest formation mechanism for the microrods was the Ostwald ripening process. It was proposed that the blocking effect of NO₃^? contributed to the formation of the rod-like powders. Moreover, the optical absorption of the prepared Bi₂Fe₄O₉ crystals was measured using an UV–vis spectrophotometer, indicating that Bi₂Fe₄O₉ powders can be used as effective photocatalysts under visible light.     

超导滤波器专用设计软件

开发了一套适用于高温超导滤波器设计的专用软件。利用该软件可快速得出高达20阶的任意结构的任意类型滤波器的传输方程、原型电路,并提取出其耦合系数矩阵。该软件可分析寄生耦合、基片厚度,介电常数误差等对滤波器的性能影响,并能由蒙特卡罗(Monte Carlo)法预测超导滤波器的产品合格率。此外,该软件提供了一个基于神经网络模型的计算机辅助调谐工具包。因而可解决超导滤波器设计、调谐的几乎所有问题,大大降低了其研制的难度和产业化的门槛。     

电离层电场电流半球模式——Ⅰ.理论分析

从定常态电离层电荷守恒方程和欧姆定律出发,导出了适用于整个半球、同时包含中性风和场向电流这种效应的电离层电场、电流基本方程组.在电离层积分电导率和中性风已知的条件下。建立了两类定解问题,并给出了数值求解方案.     

Study of the Electrical Double Layer of a Spherical Micelle: Functional Theoretical Approach

The electrical double layer theory is the base of the colloid stability theory (DLVO theory), and the PB eq. is a key to the study of the layer1,2. For a spherical particle, the PB eq. is (1) where and are the dielectric constant of the medium, the valence of ions, the elementary charge, the concentration of ions far away from the particle, the Boltzmann's constant and the temperature of the system, respectively. Since this eq. is a second order nonlinear differential one, only the anal…     

餐盒用新型非发泡聚丙烯光降解性能红外光谱法检测

用红外光谱法测试研究了餐盒用新型非发泡聚丙烯光降解行为。结果表明，降解母粒含量不同，其红外吸收光谱图存在明显的差异；在光降解过程中，羰基指数存在明显的动态变化。     

络合滴定法测定低压流体输送用镀锌焊接钢管镀锌层重量

介绍了利用络合滴定法测定低压流体输送用镀锌焊风管镀锌层重量的方法，试样用稀硫酸溶解，在ＰＨ１．５￣２．０的弱酸性介质中，以磺基水杨酸钠为指标剂，用ＥＤＴＡ滴定铁，调ＰＨ为５．５，以ＰＡＮ为指示剂，用ＥＤＴＡ滴定锌，由ＥＤＴＡ用量求出锌的重量，用ＧＢ／Ｔ３０９１－９３方法比较，试验结果满意。     

Investigation on LCST behavior of a new amorphous/crystalline polymer blend: Poly(n‐methyl methacrylimide)/poly(vinylidene fluoride)

The liquid–liquid phase‐separation (LLPS) behavior of poly(n‐methyl methacrylimide)/poly(vinylidene fluoride) (PMMI/PVDF) blend was studied by using small‐angle laser light scattering (SALLS) and phase contrast microscopy (PCM). The cloud point (T_c) of PMMI/PVDF blend was obtained using SALLS at the heating rate of 1 °C min^?1 and it was found that PMMI/PVDF exhibited a low critical solution temperature (LCST) behavior similar to that of PMMA/PVDF. Moreover, T_c of PMMI/PVDF is higher than its melting temperature (T_m) and a large temperature gap between T_c and T_m exists. At the early phase‐separation stage, the apparent diffusion coefficient (D_app) and the product (2Mk) of the molecules mobility coefficient (M) and the energy gradient coefficient (k) arising from contributions of composition gradient to the energy for PMMI/PVDF (50/50 wt) blend were calculated on the basis of linearized Cahn‐Hilliard‐Cook theory. The kinetic results showed that LLPS of PMMI/PVDF blends followed the spinodal decomposition (SD) mechanism. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1923–1931, 2008