Effect of high-voltage pulses on electrochemical properties of a molten magnesium electrolyte

Effects of high-voltage pulses on electrochemical properties of a molten magnesium electrolyte is studied experimentally. It is established that the electroconductivity of the melt subjected to the pulses and the electrolysis current at a constant voltage increase by up to 25%. The relaxation time of nonequilibrium melt reaches a few tens of minutes and under certain conditions its dynamics is oscillatory.     

Molecular Tailoring of Surfaces: Pulsed Plasma Polymerization of Bromine Containing Monomers

The use of a variable duty cycle pulsed RF plasma is shown to provide film chemistry control during polymerization of saturated (CH₂Br₂) and unsaturated (CH₂=CHCH₂Br) bromine containing monomers. With both monomers, the degree of bromine atom retention in the films is observed to increase in a progressive fashion as the RF duty cycle employed during plasma polymerization is decreased. The film deposition rates, when expressed in terms of thickness per Joule of RF energy input, increase rapidly as the RF duty cycles are reduced. Additionally, the film morphology is observed to become increasingly smooth with decreasing RF duty cycles during deposition, as illustrated with the allyl bromide monomer. The film chemistry controllability of this study is demonstrated with monomers possessing the relatively weak C-Br bond. As such, the present work represents an important extension of the pulsed plasma polymerization approach to include retention of a labile bond during film formation. The introduction of reactive surface functional groups, at controlled densities, provides additional molecular tailoring possibilities via subsequent chemical derivatization processes.     

Quantitative determination of taurine in real samples by high-performance anion-exchange chromatography with integrated pulsed amperometric detection

As taurine is a very important compound involved in a large number of metabolic processes, it is naturally present in the mammal tissues and is often deliberately added in some foods as a fortifying component. A detailed knowledge of taurine metabolic roles in biological systems can be obtained only if a sensitive, reliable and rapid analytical method is available. This article describes the successful application of high-performance anion-exchange chromatography coupled with integrated pulsed amperometric detection (HPAEC-IPAD) for taurine determination in egg white and yolk samples, as well extracts of human serum and urine. Applications are shown for determination of taurine in soft drinks and pharmaceutical preparations where the taurine content was evaluated by standard additions. These results were achieved without prior derivatization of taurine.     

电爆炸箔断路开关的理论和实验研究

 采用金属箔电爆炸过程的二维数值计算模型，对含电爆炸金属箔断路开关的电感储能脉冲功率调节系统进行了数值计算。以此为基础，研制出了一种低电感型的电爆炸箔断路开关，并以4μF/75kV脉冲电容器组作为初级能源，13Ω电阻作为负载进行实验研究。研究结果表明：在负载上可获得约250kV，脉宽大于400ns的脉冲电压。     

S-5N全固态重复频率脉冲发生器

 主要介绍S-5N的结构及测试实验结果。S-5N型全固态重复频率脉冲发生器是目前国际上同类源中峰值功率和平均功率均为最大的一台。随负载大小的变化，S-5N脉冲发生器的输出电压为400～600kV，输出电流2～3kA，输出脉冲半高宽40～50ns，单脉冲输出能量40～65J。 S-5N脉冲发生器在300Hz重复频率条件下可连续工作，500Hz重复频率条件下可连续工作3min，平均输出功率高达30kW。     

基于开关控制的兴趣实验设计

设计了开关控制实验,专门对常见的开关特点及使用进行探讨,根据开关特点搭建相应的控制电路,用近似于工程项目的形式锻炼学生对开关的灵活应用,激发了学生实验的兴趣和积极性.     

Sustainable and Robust Graphene Cellulose Paper Decorated with Lithiophilic Au Nanoparticles to Enable Dendrite-free and High-Power Lithium Metal Anode

Lithium metal anodes (LMAs) with high energy density have recently captured increasing attention for development of next-generation batteries. However, practical viability of LMAs is hindered by the uncontrolled Li dendrite growth and infinite dimension change. Even though constructing 3D conductive skeleton has been regarded as a reliable strategy to prepare stable and low volume stress LMAs, engineering the renewable and lithiophilic conductive scaffold is still a challenge. Herein, a robust conductive scaffold derived from renewable cellulose paper, which is coated with reduced graphene oxide and decorated with lithiophilic Au nanoparticles, is engineered for LMAs. The graphene cellulose fibres with high surface area can reduce the local current density, while the well-dispersed Au nanoparticles can serve as lithiophilic nanoseeds to lower the nucleation overpotential of Li plating. The coupled relationship can guarantee uniform Li nucleation and unique spherical Li growth into 3D carbon matrix. Moreover, the natural cellulose paper possesses outstanding mechanical strength to tolerate the volume stress. In virtue of the modulated deposition behaviour and near-zero volume change, the hybrid LMAs can achieve reversible Li plating/stripping even at an ultrahigh current density of 10 mA cm⁻² as evidenced by high Coulombic efficiency (97.2 % after 60 cycles) and ultralong lifespan (1000 cycles) together with ultralow overpotential (25 mV). Therefore, this strategy sheds light on a scalable approach to multiscale design versatile Li host, promising highly stable Li metal batteries to be feasible and practical.     

New designed DNA light switch Ruthenium complexes as DNA photocleavers and Topoisomerase I inhibitors

Two ruthenium complexes containing a new ligand phipz (phipz = 2‐(1,10‐phenanthroline)‐1H‐imidazo[4,5‐b]phenazine) were designed and synthesized. These complexes were found to inhibit the DNA supercoiled relaxation mediated by topoisomerase I (topo I), cleave DNA under irradiation and bind to calf thymus DNA through intercalative mode. Furthermore, complex 2 shows higher photocleavage activity, topo I inhibition activity and DNA affinity than complex 1 . Additionally, introduction of phenazine unit may be the reason that two complexes exhibit DNA ‘light switch’ behavior. The present work shows that two complexes might be potential as new DNA ‘light switches’, DNA photocleavers and topo I inhibitors.