SYNTHESIS AND CHARACTERIZATION OF SILAZANE OLIGOMER CONTAINING 1,1,3,3,5,5-HEXAMETHYLCYCLOTRISILAZANE

A new silazane oligomer containing cyclotrisilazane was synthesized by KH-catalyzed dehydro-coupling reactionsbetween diphenylsilane and 1,1,3,3,5,5-hexamethylcyclotrisilazane (D_3~N).     

Synthesis, structure and photoluminescence of [Cu(acac)(dppe)]n with novel 1D zigzag chain-like motif

A novel complex [Cu(acac)(dppe)]_n (1) [acac = acetylacetone; dppe = 1,2-bis(diphenylphosphino)ethane] was obtained by solution reactions and structurally characterized by X-ray diffraction. The crystal structure analysis indicates that the title complex is characteristic of a polymeric chain formed by the dppe ligands bridging neighboring copper centers. The copper atom is in a distorted tetrahedral geometry. Photoluminescent investigation reveals that the title complex displays a strong emission in bluelight region.     

多形性相变的分子动力学模拟

 本文利用分子动力学方法研究了KCl晶体在ρ＝ρ₀时的温度相变。面心立方（fcc）和体心立方（bcc）两种结构的径向分布函数随温度的变化的情况说明，在高压下，发生着bcc结构相fcc结构的转变，bcc结构是不稳定的。为了选取合理的势参数，利用了分子动力学程序在T＝0时的性质，计算了NaCl和KCl晶体的零温状态方程，研究了它们在压力作用下发生的多形性相变。计算表明，NaCl和KCl晶体将分别于18.8 GPa和5.9 GPa发生从fcc到bcc的多形性相变，这些值相当接近实验结果。着说明本文选用的势参数势有一定精度的。     

A new reverse Hilbert-type inequality with a best constant factor

In this paper, we give a new reverse Hilbert-type inequality with a best constant factor and some parameters. As application, we consider the equivalent form and some particular results.     

Continuous-time portfolio selection with liability: Mean–variance model and stochastic LQ approach

In this paper we formulate a continuous-time mean–variance portfolio selection model with multiple risky assets and one liability in an incomplete market. The risky assets’ prices are governed by geometric Brownian motions while the liability evolves according to a Brownian motion with drift. The correlations between the risky assets and the liability are considered. The objective is to maximize the expected terminal wealth while minimizing the variance of the terminal wealth. We derive explicitly the optimal dynamic strategy and the mean–variance efficient frontier in closed forms by using the general stochastic linear-quadratic (LQ) control technique. Several special cases are discussed and a numerical example is also given.     

Molecular designing of organic conductor based upon the model of polypyrrole

The electronic structure and properties of polypyrrole (p-Pyr) based substituting by the group of pyrazine (Pyz) and their model compounds were studied by the density functional theory (DFT) at the B3LYP level with 6-31G* basis set. The bond length, the topological analyses and nucleus-independent chemical shifts (NICS) were analyzed and correlated with the electronic properties. The bond length of all compounds is reduced with the increase in the degree of polymerization, and the band gap of these compounds is decreased. The change of NICS shows that the conjugation degree in central section of the polymeric axis is stronger than that in outer section, and the structure of central part was close to quinoid structure in polymers. The theoretical results suggest that the band gap of p-Pyz (polymer of Pyz) (0.37 eV) is much smaller than the band gap of polypyrrole (1.84 eV). The narrow band gap, large HOMO and LUMO bandwidths and small effective masses make p-Pyz have a remarkable elevation of the conductivity, so it may be considered as a very good candidate for conducting material.     

SYNTHESIS AND CHARACTERIZATION OF NOVEL REACTIVE POLYORGANOSILOXANE CONTAINING NITRO GROUPS*

 A novel reactive polyorganosiloxane containing nitro groups was first prepared by acid-catalyzed equilibration polymerization. The monomer, 3-(4-nitrophenoxy)propylmethyldichlorosilane (NPPMS), was synthesized by hydrosilylation reaction with dicyclopentadienylplatinum(II) chloride (Cp₂PtC1₂) catalyst in high yield. The synthesized polynitroorganosiloxane, which has potential application as a precursor for synthesizing advanced functional polymers, was characterized by FTIR, ¹H-NMR, ¹³C-NMR, ²⁹Si-NMR, vapor pressure osmometry (VPO) and gel permeation chromatography (GPC).     

急性心肌梗塞猝死抢救体会

总结了抢救急性心肌梗塞猝死的体会，包括：及早确诊及有效的心肺脑复苏、合理使用复苏药物和警惕老年性心梗的不典型性。