Size-dependent ignition temperature of metallic compounds fabricated by self-propagating high-temperature synthesis

Considering the diffusion reaction at solid interfaces, the ignition temperature of compounds fabricated by self-propagating high-temperature synthesis (SHS) is modelled with the help of size-dependent activation energy. As reactant size decreases, ignition temperature also decreases. This is because of increased contact areas between the reactants and the lowered diffusion barrier, both of which must be calculated specifically for reactants in nanoscale. The model predictions and experimental results are consistent for some metallic compounds.     

Spin-dependent Andreev reflection in a three-terminal Aharonov-Bohm interferometer with coherent indirect coupling

Within the framework of non-equilibrium Green’s functions, we investigate the spin-dependent Andreev reflection (AR) in a three-terminal Aharonov-Bohm interferometer with double quantum dot, taking account of the coherent indirect coupling via the superconducting reservoir. It is found that the time-reversal symmetry is broken by the crossed Andreev reflection (CAR) process, and moreover that the spin-value effect of the linear conductance, the spin-polarised AR current, and a pure spin current can be generated by means of the normal AR and the CAR. Expressions for the AR conductances (the transport coefficients) governing the AR properties of this system are derived analytically. The effect of the coherent indirect coupling on the conductance, the Andreev reflected tunneling magnetoresistance (ARTMR), and the spin-related current in the presence of the AR are amply analyzed. Our results indicate that the optimal properties of this system can be realised by tuning the external parameters.     

Analysis of ES hazards in overfilling protection gauge

Gauging operations can cause electrostatic ignition in road tankers during filling operations involving flammable liquids. For this reason, gauging from above the liquid surface should not be carried out in a road tanker containing a flammable atmosphere when hazardous conditions are present.Introduction of an overfilling sensor to automatically stop the filling in case of deviation can be a safety measure to prevent overfilling of the road tanker and the generation of a rather big flammable pool.Nevertheless, this situation generates a conflict of interest with the formerly described safety measure of preventing a charged liquid to approach a counter-electrode in presence of a explosive atmosphere.This situation has been assessed in detail by using a simulation program. It was clear that the gauge could lead to an ignition already when the liquid approached the edge of the gauge. A new design was defined to prevent such hazard.     

Improvement to the exchange field acting upon Tb ions in TbIG

The spin fluctuations of the magnetic ions play an important role on the magnetic properties of the crystals and lead to a new mechanism for the Curie-Weiss susceptibility. The exchange field H_exch acting on the rare-earth ions in Tb:YIG is improved based on the temperature dependence of the spin fluctuations, which is expressed as H_exch=n₀(1+γT+βT⁻²)M_YIG. By means of the improved exchange field, the magnetic and magneto-optical properties of Tb³⁺ ions in Tb:YIG are calculated. The calculated results are in good agreement with the measured data in the temperature range from 40 to 300 K.     

Multi-mode Spiral Wave in a Coupled Oscillatory Medium

Multi-mode spiral wave and its breakup in 1-d and 2-d coupled oscillatory media is studied here by theoretic analysis and numerical simulations. The analysis in 1-d system shows that the dispersion relation curve could be nonmonotonic depending on the coupling strength. It may also lead to the coexistence of different wave numbers within one system. Direct numerical observations in 1-d and 2-d systems conform to the prediction of dispersion relation analysis. Our findings indicate that the wave grouping can also be observed in oscillatory media without tip meandering and waves with negative group velocity can occur without inhomogeneity.     

改性乙醇胺富集烟道气中CO2的FTIR研究

以四(3,5-二叔丁基-4-羟基苯基丙酸)季戊四醇酯(抗氧剂1010)、Na2SO3作为乙醇胺(MEA)的氧化降解的改性剂,考察改性MEA富集模拟烟道气中CO2的效果,利用气相色谱、红外光谱分析抗氧剂1010与Na2SO3的适宜用量、比较两种抗氧剂的抗氧化性能.结果表明,抗氧剂1010和亚硫酸钠的添加量在0.15%时效...     

Inspection of the efficiency of conductive clothing examination

High voltage live-line maintenance (LLM) is a commonly applied method worldwide to execute planned works in the grid economically [1]. In case of bare-hand technique workers wear a so-called conductive clothing acting as a Faraday-cage which protects them against the high electric fields during the work.     

Influence of magnetic powders on the tribological performance of a novel magnetic brake material

By adding magnetic powders into matrix material, it has been proved to be a creative approach to improve tribological properties of brake materials. In this paper, a novel magnetic brake material with Nd–Fe–B and nano-Fe₃O₄ was developed, and the influential mechanism of these two magnetic powders and their content on the friction and wear performance was deeply discussed. Firstly, some experiments were carried out to investigate the tribological performance and influential mechanisms of four groups of brake pad samples with different magnetic powders. Furthermore, based on these results, further experiments for investigating the influence that Nd–Fe–B contents have on the tribological properties were conducted. According to the theoretical analysis about experiments, it was concluded that nano-Fe₃O₄ is beneficial to promote the formation of friction film and has certain lubricant effects. However, Nd–Fe–B has double effects on the formation of friction film. It will have positive effects when its content is less than a certain value. Otherwise, it will destroy the structure of friction film. Conclusively, it is believed that this study will be significantly valuable and meaningful for developing new brake materials and improving safety reliability of mechanical brakes.     

麦克斯韦等面积法则在范氏气体中的应用

对与范德瓦耳斯气体状态方程有关的几个问题作了进一步分析,给出了一种证明麦克斯韦等面积法则的方法,并指出了有关文献的不妥之处.