Kinetic Studies on the Reaction of Sodium Hexa-cyanoferrate(II) Complex with Peroxydisulfate Anion

Introduction In the previous studies on the oxidation reaction,peroxydisulfate was widely used as an oxidizingagent.1-5 One of the advantages of this oxidant lies in itsstability in a wide range of pH values. The reaction be-tween Fe(CN)5L3- (L=N-aromatic heterocyclic li-gands) and S2O8 2- has been proved to proceed throughan outer-sphere electron transfer mechanism.5 For a re-action [(Eq. (1)] to be under an outer-sphere mechanismthe steps involved are the formation of a reactant …     

4,4'-二氨基三苯胺的合成与纯化

以苯胺和对硝基氯苯为原料, K₂CO₃作催化剂, 合成出了中间产物4,4'-二硝基三苯胺(DNTPA). 将中间产物用10%(质量分数)的Pd/C催化剂加氢催化还原, 得到纯度为96.6%的目标产物4,4'-二氨基三苯胺(DATPA), 合成总产率为38%. 与其它方法相比, 该方法原料便宜易得, 纯度很高, 产物可作为反应的单体原料.     

New products from the reaction of acetyllycoctonine with N-bromosuccinimide (NBS)

Six new artificial products 11-16 were obtained from the reaction of acetyllycoctonine (10) with N-bromosuccinimide (NBS). The structures of these compounds were established on the basis of spectral data. It is emphasized that the varieties and yields of the products in this reaction depended greatly upon reaction conditions and the types of substrate.     

桥联双核配合物[(DPC)2Co2(H2O)5]·2H2O的合成与晶体结构

The new complex formulated [(DPC)₂Co₂(H₂O)₅]·2H₂O (HDPC^- is pyridine-2,6-dicarboxylate) has been synthesized and the crystal structure was determined by X-ray diffraction. The crystal structure of the complex belongs to monoclinic system with space group P2₁/c, a=0.83850(10) nm, b=2.7386(4) nm, c=0.9610(2) nm, β=98.280 (10) °, V=2.1838(6) nm³, Z=4, D_c=1.746 g·cm^-3, μ=1.597 mm^-1. In the crystal the two Co²⁺ are in distorted octahedrons. The part of [Co(DPC)₂] possess an approximate D_2d symmetry, while the part of [OCo₍₂₎(OH₂)₅] has an approximate C₂ symmetry.     

Mixing of Racemic Poly(L-lactide)/Poly(D-lactide) Blend with Miscible Poly(D,L-lactide):Toward All Stereocomplex-type Polylactide with Strikingly Enhanced SC Crystallizability

Stereocomplex-type polylactide (SC-PLA) consisting of alternatively arranged poly(L-lactide) (PLLA) and poly(D-lactide) (PDLA) chains has gained a good reputation as a sustainable engineering plastic with outstanding heat resistance and durability,however its practical applications have been considerably hindered by the weak SC crystallizability.Current methods used to enhance the SC crystallizability are generally achieved at the expense of the precious bio-renewability and/or bio-degradability of PLAs.Herein,we demonstrate a feasible method to address these challenges by incorporating small amounts of poly(D,L-lactide) (PDLLA) into linear high-molecular-weight PLLA/PDLA blends.The results show that the incorporation of the atactic PDLLA leads to a significant enhancement in the SC crystallizability because its good miscibility with the isotactic PLAs makes it possible to greatly improve the chain mixing between PLLA and PDLA as an effective compatibilizer.Meanwhile,the melt stability (i.e.,the stability of PLLA/PDLA chain assemblies upon melting) could also be improved substantially.Very intriguingly,SC crystallites are predominantly formed with increasing content and molecular weight of PDLLA.More notably,exclusive SC crystallization can be obtained in the racemic blends with 20 wt％ PDLLA having weight-average molecular weight of above 1 ×10s g/mol,where the chain mixing level and intermolecular interactions between the PLA enantiomers could be strikingly enhanced.Overall,our work could not only open a promising horizon for the development of all SC-PLA-based engineering plastic with exceptional SC crystallizability but also give a fundamental insight into the crucial role of PDLLA in improving the SC crystallizability of PLLA/PDLA blends.     

Spatial anisotropy: a method to study anisotropic flow in heavy ion collisions

We introduce a method to study anisotropic flow parameter v<,n> as a collective probe to Quark Gluon Plasma in relativistic heavy ion collisions. The emphasis is put on the use of the Fourier expansion of initial spatial azimuthal distributions of participant nucleons in the overlapped region. The coefficients ε<,n> of Fourier expansion are called the spatial anisotropy parameter for the n-th harmonic. We propose that collective dynamics can be studied by v<,n>/ε<,n>. In this paper, we will discuss in particular the second (n=2) and the fourth (n=4) harmonics.     

A DFT Study on the Stable Structures and Dissociation Mechanism of C3O6 Cluster

Using geometrical optimization and DFT method at the B3LYP/6-31G (d) level, nineteen equilibrium geometries were identified, and three transition states of dissociation reaction of C3O6 clusters were also found. The vibrational frequencies and intrinsic reaction coordinate (IRC) verification at the same level were computed to verify the transitions. And then we calculated the dissociation energies and analyzed the dissociation channels. The computational results show that the dissociation energies of C3O6 isomers relative to three CO2 are between 1.509 × 103 and 10.61 × 103 kJ·kg-1, and the energy barriers of the reactions are 92.857, 131.138 and 185.793 kJ·mol-1. Both the high dissociation energies and high energy barriers show that C3O6 clusters studied in this paper are stable enough to be used as high-energy-density materials.     

噪声模态单元预判的经验模态分解脉冲星信号消噪

为了改善脉冲星辐射脉冲信号的消噪效果, 提出了一种基于噪声模态单元预判的经验模态分解(EMD) 消噪声方法. 该方法首先利用EMD将含噪辐射脉冲信号分解为一组内蕴模态函数(IMF), 根据IMF系数的统计特性采用局部均方误差准则进行噪声模态单元预判, 并将噪声模态单元置零; 然后对噪声模态单元预判处理后的IMF以模态单元为基本单位进行最优比例萎缩消噪, 从而达到抑制噪声、保留信号的目的. 实验结果表明: 与Sure Shrink小波阈值法、Bayes Shrink小波阈值法和EMD模态单元比例萎缩法相比, 基于噪声模态单元预判的EMD消噪方法可以更有效地去除脉冲辐射信号中的噪声, 同时更好地保留信号突变处的细节信息特征, 在信噪比、 均方误差、峰值相对误差、峰位误差和相位误差等方面都有一定程度的改善. 关键词： 脉冲星信号消噪 经验模态分解 噪声模态单元预判 局部均方误差     

基于独立成分分析和经验模态分解的混沌信号降噪

基于经验模态分解和独立成分分析去噪的特点,提出了一种联合独立成分分析和经验模态分解的混沌信号降噪方法. 利用经验模态分解对混沌信号进行分解,根据平移不变经验模态分解的思想构造多维输入向量, 通过所构造的多维输入向量和独立成分分析对混沌信号的各层内蕴模态函数进行自适应去噪处理; 将处理后的所有内蕴模态函数进行累加重构,从而得到降噪后的混沌信号. 仿真实验中分别对叠加不同强度高斯噪声的Lorenz混沌信号及实际观测的月太阳黑子混沌序列进行了研究, 结果表明本文方法能够对混沌信号进行有效的降噪,而且能够较好地校正相空间中点的位置, 逼近真实的混沌吸引子轨迹. 关键词： 独立成分分析 经验模态分解 混沌信号 降噪     

锰（Ⅲ）5,10,15-三（五氟苯基）-Corrole配合物的DFT计算

在6-31G*水平上采用DFT(UB3LYP)方法对锰(Ⅲ)5,10,15-三(五氟苯基)-corrole[(TPFC)MnⅢ]及其咪唑轴向配位加合物(TPFC)MnⅢ(Im)进行了几何结构全优化.计算结果表明,咪唑的配位作用不会改变其基态的高自旋(s=2)特性.(TPFC)MnⅢ与咪唑配位形成轴向加合物后,其中心金属Mn原子偏离平面结构,与corrole大环N4平均平面的距离达到0.02734 nm.NBO分析显示(TPFC)MnⅢ和(TPFc)MnⅢ(Im)中心金属锰的电子组态为(dxz)1(dyz)1(dz2)1(dx2-y2)1(dxy)0(TPFC)MnⅢ(Im)前线分子轨道能级明显上升,从其β-(LUMO+3)轨道可见咪唑配位N原子的py轨道与中心金属Mn原子撕道形成了d-pπ轨道.TD-DFT计算发现,(TPFC)MnⅢ和(TPFC)MnⅢ(Im)电子光谱Q带的"四轨"特征比B带明显;(TPFC)MnⅢ的CT带主要源自β-(HOMO-1)→β(LUMO+5)和β-HOMO→β-(LUMO+4)的跃迁,(TPFC)MnⅢ(Im)的CT带则主要源自β-(HOMO-1)→β-(LUMO+3)和β-HOMO→β-(LUMO+4)的跃迁.