羟自由基对支撑磷脂双层膜的破坏及水溶性抗氧化剂保护作用的电化学研究

以支撑磷脂双层膜(supported bilayer lipid membrane, s-BLM)作为生物膜模型, 利用Fenton体系产生羟自由基(hydroxyl free radical, •OH), 采用循环伏安法研究了s-BLM与•OH之间的相互作用. 结果表明: •OH通过与磷脂发生化学反应, 诱发s-BLM上形成孔洞或缺陷, 这种作用对时间、FeSO₄和H₂O₂的浓度具有依赖性, 且不可恢复. 具有还原性基团的抗氧化剂维生素C, 还原型谷胱甘肽和L-半胱氨酸, 通过与•OH发生氧化还原反应, 可抑制•OH与s-BLM的相互作用, 降低•OH对s-BLM结构的破坏程度.     

Flame-retardant effect of cross-linked phosphazene derivatives and pentaerythritol derivatives on polypropylene

Journal of Thermal Analysis and Calorimetry - A phosphazene-based flame retardant (PBFA) was synthesized by hexachlorocyclotriphosphazene and N-aminoethylpiperazine. To improve the flame retardancy...     

氙灯光源太阳模拟器辐照衰减器设计方法

针对应用于太阳模拟器辐照衰减器设计上的不足,提出一种新的衰减器设计方法,旨在提高其辐照均匀性.基于光学扩展量计算衰减器上的网孔面积,对会聚光路的辐射通量进行调制;利用聚光镜环带法,理论上分析衰减器上的辐射分布;利用网孔非均匀分布的结构对会聚光路的辐射分布进行调制,给出具体设计参数;对比分析了网孔均匀分布和非均匀分布对辐...     

A novel superjunction MOSFET with improved ruggedness under unclamped inductive switching

The ruggedness of a superjunction metal–oxide semiconductor field-effect transistor (MOSFET) under unclamped inductive switching conditions is improved by optimizing the avalanche current path. Inserting a P-island with relatively high doping concentration into the P-column, the avalanche breakdown point is localized. In addition, a trench type P+ contact is designed to shorten the current path. As a consequence, the avalanche current path is located away from the N+ source/P-body junction and the activation of the parasitic transistor can be effectively avoided. To verify the proposed structural mechanism, a two-dimensional (2D) numerical simulation is performed to describe its static and on-state avalanche behaviours, and a method of mixed-mode device and circuit simulation is used to predict its performances under realistic unclamped inductive switching. Simulation shows that the proposed structure can endure a remarkably higher avalanche energy compared with a conventional superjunction MOSFET.     

Organocatalytic Lithium Chloride Oxidation by Covalent Organic Frameworks for Rechargeable Lithium-Chlorine Batteries

Rechargeable Li−Cl₂ battery is a promising high energy density battery system. However, reasonable cycle life could only be achieved under low specific capacities due to the sluggish oxidation of LiCl to Cl₂. Herein, we propose an amine-functionalized covalent organic framework (COF) with catalytic activity, namely COF−NH₂, that significantly decreases the oxidation barrier of LiCl and accelerates the oxidation kinetics of LiCl in Li−Cl₂ cell. The resulting Li−Cl₂ cell using COF−NH₂ (Li−Cl₂@COF−NH₂) simultaneously exhibits low overpotential, ultrahigh discharge capacity up to 3500 mAh/g and a promoted utilization ratio of deposited LiCl at the first cycle (UR−LiCl) of 81.4 %, which is one of the highest reported values to date. Furthermore, the Li−Cl₂@COF−NH₂ cell could be stably cycled for over 200 cycles when operating at a capacity of 2000 mAh/g at −20 °C with a Coulombic efficiency (CE) of ≈100 % and a discharge plateau of 3.5 V. Our superior Li−Cl₂ batteries enabled by organocatalyst enlighten an arena towards high-energy storage applications.     

A633D斗杆的疲劳裂纹形成寿命

分析了A633D钢焊接接头在循环哉荷下的疲劳特性,进行了疲劳特性和静态拉伸实验,得到了该材料的静力参数,常规机械性能,焊接接头的循环σ-ε曲线以及焊接接头的应变寿命曲线,将局部应力－应变法用于该材料的10m3斗杆的裂纹形成寿命的估算,采用Miner法则结合概率的方法计算了不同可靠度下的疲劳寿命,其间考虑了焊接残余应力的影响,得出了焊接残余应力的存在使斗杆的裂纹形成寿命降低约10％。     

基于偏振模式转换的声光陀螺研究

提出一种基于偏振模式转换的声光陀螺,分析其原理与结构并对该陀螺进行实验测试。静态测试结果表明,当声光作用长度为15mm,声表面波输入功率为100mW,频率为168.201MHz时,偏振模式转化效率为80.02%。在偏置条件下进行旋转测试,得到输出电压随陀螺转速呈线性变化的曲线,其灵敏度约为1mV/[(°)/s]。偏振型声光陀螺保留声表面波陀螺体积小、成本低等优点,而在灵敏度上有大幅提高。     

一种可能形成POPs途径的初探-气相苯的氯化反应

用串联质谱碰撞室模拟大气环境研究了持久性有机污染物(POPs)形成过程,实验发现,经离子-分子反应可以生成氯苯类化合物。 以中性苯与酰氯为反应物在离子源进行反应,在苯含量为4×10^-3Pa、酰氯含量为4×10^-4Pa时,氯苯的生成量为5×10^-8Pa,远远高于背底浓度5×10^-9Pa。对氯苯类化合物的形成,大气环境明显优于质谱环境,实验结果表明,在大气中经离子分子反应形成POPs是可能的。     

磁性聚乙烯醇微球的制备及表征

为了制备表面具有羟基且有一定磁响应性的聚乙烯醇微球,本文采用反相乳化的方法,以液体石蜡为连续相,在Fe3O4磁流体存在下,通过戊二醛交联聚乙烯醇(PVA)。对微球的形貌,表面羟基含量,微球密度,微球Fe含量以及微球的磁响应性进行了研究。制得了粒径分布为25μm~150μm,表面羟值为11mmol/g~20mmol/g的磁性聚乙烯醇微球。     

Guest‐Induced Transformation of a Porphyrin‐Edged FeII4L6 Capsule into a CuIFeII2L4 Fullerene Receptor

The combination of a bent diamino(nickel(II) porphyrin) with 2‐formylpyridine and Fe^II yielded an Fe^II₄L₆ cage. Upon treatment with the fullerenes C₆₀ or C₇₀, this cage was found to transform into a new host–guest complex incorporating three Fe^II centers and four porphyrin ligands, in an arrangement that is hypothesized to maximize π interactions between the porphyrin units of the host and the fullerene guest bound within its central cavity. The new complex shows coordinative unsaturation at one of the Fe^II centers as the result of the incommensurate metal‐to‐ligand ratio, which enabled the preparation of a heterometallic cone‐shaped Cu^IFe^II₂L₄ adduct of C₆₀ or C₇₀.