有机金属衍生物α，β-［(RSn)3GeW9O37］7-的合成与性质研究

本文报道了α，β-M₄H₃［(RSn)₃GeW₉O₃₇］·nH₂O(M=Bu₄N⁺, Me₄N⁺; R=Bu, Ph)杂多配合物的合成、表征及催化性能研究、元素分析、红外光谱和紫外光谱、¹H、¹¹⁹Sn和¹⁸³W核磁共振谱、激光飞行时间(TOF)质谱和极谱数据表明，这些新化合物为三取代的Keggin结构，三个(RSn)³⁺属不同的M₃O₁₃单元并且彼此共角相连，标题杂多化合物主要以单体形式存在且对烯烃环氧化反应具有催化活性。     

含二茂铁和吡啶单元的手性席夫碱配体在钌催化的不对称氢转移反应中的应用

Chiral Schiff base complexes are very efficient for a wide range of reactions, including expoxidation[1], epoxide ring opening[2], Diels-Alder reaction[3], aldol reaction[4], etc. However, there are only few examples of P-N chelate Schiff bases being used as the chiral ligands in the asymmetric transfer hydrogenation of ketones. Recently, Gao et al[5] reported a series of P,N,N,P Schiff base ligands that have relatively low enantioselectivity in the asymmetric transfer hydrogenation of ketones.     

脑胶质瘤磁共振弥散张量成像定量参数与VEGF、MMP-9表达的相关性

本研究旨在分析脑胶质瘤患者的磁共振弥散张量成像(DTI)参数与病变组织血管内皮生长因子(VEGF)和基质金属蛋白酶-9(MMP-9)表达的相关性,以及DTI参数对脑胶质瘤进行分级诊断的价值.根据病理分级将102例脑胶质瘤患者分为低级别组(47例)和高级别组(55例),均行MRI和DTI检查,定量测定表观弥散系数(ADC...     

An Aluminum–Sulfur Battery with a Fast Kinetic Response

The electrochemical performance of the aluminum‐sulfur (Al‐S) battery has very poor reversibility and a low charge/discharge current density owing to slow kinetic processes determined by an inevitable dissociation reaction from Al₂Cl₇^? to free Al³⁺. Al₂Cl₆Br^? was used instead of Al₂Cl₇^? as the dissociation reaction reagent. A 15‐fold faster reaction rate of Al₂Cl₆Br^? dissociation than that of Al₂Cl₇^? was confirmed by density function theory calculations and the Arrhenius equation. This accelerated dissociation reaction was experimentally verified by the increase of exchange current density during Al electro‐deposition. Using Al₂Cl₆Br^? instead of Al₂Cl₇^?, a kinetically accelerated Al‐S battery has a sulfur utilization of more than 80 %, with at least four times the sulfur content and five times the current density than that of previous work.     

Sonochemical growth of lanthanum conversion films using ultrasonic immersion method for performance improvement of zinc electrodes

The growth of lanthanum conversion coatings on the zinc powder modified by ultrasonic immersion is deeply investigated by Auger electron spectroscopy, X-ray photoelectron spectroscopy, spectrophotometrical and other characterization techniques. The conversion kinetics of La element and the growth mechanism of lanthanum conversion layers are also reported and proposed. The influence of the lanthanum conversion coatings on the discharge properties and cycle behaviors of zinc electrodes is evaluated through charge–discharge measurements and cycle voltammetry. It is found that La₂O₃ and ZnO compose the lanthanum conversion films and trace content of La element in modified zinc powder can be controlled by varying the ultrasonic power. Furthermore, the superior performance of zinc electrode using the zinc powder coated with lanthanum conversion films is clearly established by low capacity loss and high cycle stability. The great improvement over the electrochemical properties of zinc electrodes should be ascribed to the physical shielding effect of lanthanum conversion layers.     

Fabrication of Fe-doped Co-MOF with mesoporous structure for the optimization of supercapacitor performances

We fabricated mesoporous hybrid dual-metal Co and Fe containing metallic organic framework (Co/Fe-MOF), Fe-MOF, and Co-MOF in the ionic liquid (IL)/supercritical CO₂ (SC)/surfactant emulsion system, and then studied the electrochemical properties of the three MOFs systematically.     

1-(Z)-[2-(三芳基锡基)乙烯基]环戊醇及其衍生物的合成及生物活性

合成了１４种新的（Ｚ）－［２－（三芳基锡基）乙烯基］环戊醇类有机锡化合物,通过元素分析,ＩＲ、＾１Ｈ ＮＭＲ 对所合成的化合物进行了表征,结果表明（Ｚ）－［２－（三芳基锡基）乙烯基］环戊醇类有机锡化合物中乙烯式双键为顺式构型,分子内羟基与锡原子发生配位,形成五元螯合环。生物活性测定结果表明,二卤化物在抗癌,免疫及受体作用等方面具有优良的活性。     

Spiky Steady States of a Chemotaxis System with Singular Sensitivity

This paper is concerned with the steady state problem of a chemotaxis model with singular sensitivity function in a one dimensional spatial domain. Using the chemotactic coefficient \(\chi \) as the bifurcation parameter, we perform local and global bifurcation analysis for the model. It is shown that positive monotone steady states exist as long as \(\chi \) is larger than the first bifurcation value \(\bar{\chi }_1.\) We further obtain asymptotic profiles of these steady states, as \(\chi \) becomes large. In particular, our results show that the cell density function forms a spike, which models the important physical phenomenon of cell aggregation.     

1-[(Z)-2-(-苯基二溴化锡基)乙烯基]环戊醇的合成及晶体结构

通过１［（Ｚ）２（三苯基锡基）乙烯基］环戊醇与Ｂｒ２反应制得了新化合物１［（Ｚ）２（苯基二溴化锡基）乙烯基］环戊醇．通过元素分析、锡含量测定、ＩＲ、１ＨＮＭＲ对其进行了表征并用Ｘ射线衍射法测得了所合成化合物的晶体结构．该化合物属正交晶系，Ｐ２１２１２１空间群，晶胞参数：ａ＝０８６７５（４）ｎｍ，ｂ＝１２５２３（７）ｎｍ，ｃ＝１４００９（８）ｎｍ；Ｚ＝４，Ｖ＝１５２１９ｎｍ３，Ｄｃ＝２．３９ｃｍ３，ｕ＝２３．７２ｃｍ－１．结构分析表明，标题化合物分子为畸变的三角双锥构架，双键的两个氢取顺式结构，分子中Ｏ与Ｓｎ配位，形成五元螯合环结构     

Electron-withdrawing functional ligand promotes CO2 reduction catalysis in single atom catalyst

Science China Chemistry - Electrochemical carbon dioxide reduction reaction (CO2RR) powered by renewable electricity offers an attractive approach to reduce carbon emission and at the same time...