恒电流库仑分析法测定乙烯基三乙氧基硅烷

建立了恒电流库仑分析法测定乙烯基三乙氧基硅烷(VTES)含量的方法. 探讨了电解液、反应时间、极化电位、溶剂等因素对测定的影响. 结果表明, 选用V(甲酸)∶V(KBr (2 mol/L))∶V(乙醇)＝6∶1∶3为电解液, 极化电位为200 mV, VTES与溴的四氯化碳溶液反应30 min, 甲醇为VTES的溶剂时测定结果最佳. 该方法用于样品VTES的测定, 加标回收率为98.4%～102.7%, 相对标准偏差为1.7%.     

Surfactant media for constant-current coulometry. Application for the determination of antioxidants in pharmaceuticals

Effect of surfactant presence on electrochemical generation of titrants has been evaluated and discussed for the first time. Cationic (1-dodecylpyridinium and cetylpyridinium bromide), anionic (sodium dodecyl sulfate) and nonionic (Triton X100 and Brij^® 35) surfactants as well as nonionic high molecular weight polymer (PEG 4000) do not react with the electrogenerated bromine, iodine and hexacyanoferrate(III) ions. The electrogenerated chlorine chemically interact with Triton X100 and Brij^® 35. The allowable range of surfactants concentrations providing 100% current yield has been found. Chain-breaking low molecular weight antioxidants (ascorbic acid, rutin, α-tocopherol and retinol) were determined by reaction with the electrogenerated titrants in surfactant media. Nonionic and cationic surfactants can be used for the determination of antioxidants by reaction with the electrogenerated halogens. On contrary, cationic surfactants gives significantly overstated results of antioxidants determination with electrogenerated hexacyanoferrate(III) ions. The use of surfactants in coulometry of α-tocopherol and retinol provides their solubilization and allows to perform titration in water media. Simple, express and reliable coulometric approach for determination of α-tocopherol, rutin and ascorbic acid in pharmaceuticals using surfactant media has been developed. The relative standard deviation of the measurements does not exceed of 5%.     

Functional evaluation of a liquid-molding two component combination resin

Functional parameters contributing to the recognizable good performance of a highly crosslinked olefinic polymer based on cyclopentadiene have been evaluated by a limited range of stress decay and creep recovery from a fixed deformation over constant time periods. The experimental design for these involved a calculated stress (load) at the initial sample deformation (displacement) for determination of changes in stress in bending mode and flex creep under applied load at three constant temperature segments of 6 h each with 20 min recovery time between segments. The results have identified a behavior which is typical of interfacial orientational effect in a two-component system. Thermal conductivity, heat capacity and density at the same temperatures were measured for determination of variations in thermal diffusivity as an indication of the competing effects of densification and thermal expansion for such a system.Static charging and polarization experiments were performed for evaluation of other desired uses of this material, in moving parts and in direct or induced voltage applications. The latter allows measurement of dynamic charge transport through the resin matrix. Calculations indicate generation of charge carriers from weak secondary bonding typical of polymer interlaces. The polarization itself consists of dipole orientation characterized by relatively high activation energy.The intrinsic mechanical properties for this material had been determined by the manufacturer, but the performance parameters reported in this study have been determined for the first time for exploration of further uses for this material.The author wishes to acknowledge the assistance provided by Ralph Pitman in the preparation of the samples for this work.     

Fluctuations in Extractable Work and Bounds on the Charging Power of Quantum Batteries

Motivated by a recent disagreement about the claim that fluctuations in the free energy operator bound the charging power of a quantum battery, we present a critical analysis of the original derivation. The analysis shows that the above claim does not hold for both closed- and open-system dynamics. Our results indicate that the free energy operator is not a consistent quantifying operator for the work content of a charging quantum battery.     

A Novel Epidemic Model Base on Pulse Charging in Wireless Rechargeable Sensor Networks

As wireless rechargeable sensor networks (WRSNs) are gradually being widely accepted and recognized, the security issues of WRSNs have also become the focus of research discussion. In the existing WRSNs research, few people introduced the idea of pulse charging. Taking into account the utilization rate of nodes’ energy, this paper proposes a novel pulse infectious disease model (SIALS-P), which is composed of susceptible, infected, anti-malware and low-energy susceptible states under pulse charging, to deal with the security issues of WRSNs. In each periodic pulse point, some parts of low energy states (LS nodes, LI nodes) will be converted into the normal energy states (S nodes, I nodes) to control the number of susceptible nodes and infected nodes. This paper first analyzes the local stability of the SIALS-P model by Floquet theory. Then, a suitable comparison system is given by comparing theorem to analyze the stability of malware-free T-period solution and the persistence of malware transmission. Additionally, the optimal control of the proposed model is analyzed. Finally, the comparative simulation analysis regarding the proposed model, the non-charging model and the continuous charging model is given, and the effects of parameters on the basic reproduction number of the three models are shown. Meanwhile, the sensitivity of each parameter and the optimal control theory is further verified.     

紧凑型全固态高重复频率LC-Marx脉冲发生器

通过理论、模拟和实验对提出的全固态LC-Marx发生器进行研究。整个系统由一个MOSFET开关和多个由一个磁芯制成的磁开关控制,该脉冲发生器直径为140 mm,高为17 mm,且随着级数的增加尺寸和重量基本不变。运用谐振充电可以使电容充到源电压的1.82倍,五级LC-Marx发生器用950 V直流电压充电时,在500 Ω电阻上得到峰值电压为10.9 kV、半高宽为400 ns、上升时间为85 ns、效率为30.43%的高压脉冲。输出电压的上升前沿可以根据实际应用的要求,通过减小电容量缩短。该脉冲发生器在频率低于30 kHz下,可以持续稳定地运行。该LC-Marx脉冲发生器在气体放电中将具有较好的应用效果。     

μs级充电时水介质同轴电容击穿实验研究

研制了水介质同轴电容的实验装置,在此装置上进行了大量的实验。测得μs级充电时,水介质同轴电容分别在正脉冲和负脉冲充电时的击穿电压,负击穿电压的理论值与测量值相差较大,正击穿电压的理论值大于测量值的18%左右,对此实验结果进行了分析。此外,当去离子水的电阻率从13MΩ·cm降到5 MΩ·cm时,水介质同轴电容器的击穿电压基本不变。     

充电不均匀对脉冲形成系统输出方波脉冲平顶的影响

在对脉冲形成线进行充电时,由于充电时间较短,以及形成线具有一定的长度,往往会使得充电电压在脉冲形成线上存在一定的不均匀性,从而影响到负载输出电压。对此进行了理论和模拟研究,分析了引起充电不均匀的原因和机制;在此基础上,通过求解不均匀充电初始条件下的电报方程,得到负载输出电压,并进行了模拟。结果表明,充电不均匀会引起负载输出电压平顶的起伏。     

Detection of hydrogen in neutron-irradiated nickel using positron lifetime spectroscopy

Hydrogen in nano-voids in neutron-irradiated nickel has been detected using positron annihilation lifetime spectroscopy (PALS). As positron lifetime is greatly affected by nano-voids bound with hydrogen, special attention was paid to the analysis. The positron lifetime of neutron-irradiated nickel at higher irradiation doses increased with the dose, which is an indicator for vacancy cluster (nano-void) formation in the lattice. The introduction of hydrogen in well-annealed nickel by electrical charging also resulted in an increase in positron lifetime due to vacancy formation. In neutron-irradiated nickel specimens, hydrogen charging shortened the positron lifetime from 456 to 334 ps (irradiation dose: 3 × 10^?3 dpa). Isochronal annealing behaviour of hydrogen-charged nickel and neutron-irradiated nickel was also studied. Positron trapping rate was calculated using a simple trapping model. Thermal desorption spectroscopy was used for the investigation of hydrogen behaviour in non-irradiated hydrogen-charged nickel.