La2O3-Mo5Si3/MoSi2复合材料的高温氧化行为

研究了0．8％La2O3-MosSi3／MoSi2复合材料在1200℃空气中的高温氧化行为。结果表明：0．8％稀土和MoSi3的加入，使材料的抗氧化性能降低。MosSi3含量越高，材料的抗氧化性能越差。当MosSi3含量低于30％时，在氧化初始阶段，质量变化呈直线下降，随着氧化的进行，氧化逐渐增重，材料表面形成较致密的SiO2阻止了材料的进一步氧化，使得氧化增重较小。而0．8％La2O3-40％Mo5Si3／MoSi2复合材料却出现了“粉化”现象。0．8％La2O3．MosSi3／MoSi2复合材料抗氧化性能的降低，归因于Mo5Si3差的抗氧化性和材料致密度的降低；另外，稀土和Mo5Si3的加入，细化了材料的晶粒，使晶界面积增加，加速了氧在晶界中的扩散，促进了材料的氧化。     

稀土对MoSi2力学性能和抗氧化性能的影响

采用自蔓延和真空烧结方法制备了掺杂0．9％La2O3的MoSi2基复合材料，利用热重分析法，SEM和X射线考察了La2O3颗粒对MoSi2力学性能、抗氧化特性以及循环氧化后力学性能的影响。结果表明，与纯MoSi2相比，RE／MoSi2材料的弯曲强度和断裂韧性分别提高了46％和78％；稀土对MoSi2材料的强韧化机制主要是细晶强化、弥散强化和细晶韧化。RE／MoSi2的氧化增重是纯MoSi2的2．5倍，稀土使MoSiz材料的抗氧化性能降低。由于纯MoSi2材料氧化后的晶粒长大，其抗弯强度比氧化前降低了17％。稀土对MoSi2氧化时的晶粒长大倾向有抑制作用，使得RE／MoSi2材料的抗弯强度基本不变。     

Effect of the Coil Angle in an Inductively Coupled Plasma Torch: A Novel Two-Dimensional Model

A two-dimensional model has been developed for the calculation of the electromagnetic (EM) fields generated by spiral coil currents, in order to obtain a better representation of the actual configuration used in a typical inductively coupled plasma (ICP) torch. In order to obtain the EM fields in a two-dimensional model, the change of EM field in tangential direction is neglected and the coil is assumed to be a concentric cylinder. In order to justify our assumption, the EM, flow and temperature fields resulting from five-ring coil and concentric cylinder coil are compared and the results are almost the same except for the EM field in the vicinity of the coil. In the case of the spiral coil, the coil current is inclined with respect to the horizontal plane. Therefore current in the cylinder coil is assumed to have the same inclined angle, which is split into tangential and axial components. The axial electric field and hence an axial current in plasma is induced by the axial component of the spiral coil current. Charge density is accumulated in the plasma, since the axial current cannot form a loop. In order to obtain the EM field and the charge distribution in the plasma generated by the spiral coil, the equations of axial vector potential and electrostatic potential have been derived. Due to the swirling Lorentz force (J_z×B_r) an axisymmetrical swirling fluid model is used to simulate the plasma flow in an axisymetrical configuration. With an inclined angle of the coil current being 3.7° and the frequency being 3 MHz, computational results show that the swirling Lorentz force causes plasma swirling with a maximum speed of 3.41 m/s near the plasma center when the injected sheath gas and central gas are not swirling. In these conditions, the real and imaginary parts of the maximum electrostatic potential are 0.95 V and 1.66 V, respectively. When the electrostatic field is neglected, the swirling velocity of the plasma is 3.95 m/s.     

Photoelectrochemical Detection of H2O2 Based on Flower‐Like CuInS2‐Graphene Hybrid

A novel photoelectrochemcial biosensing system was fabricated based on the composition of horseradish peroxidase (HRP), flower‐like CuInS₂ (CIS) and graphene on indium tin oxide (ITO) electrode for detecting H₂O₂. The graphene layer was used as highly conductive scaffolds for electron transport from the ITO electrode to CIS. Furthermore, the flower‐like CIS enhanced the multi‐reflection of light and provided matrixes for the adsorption of HRP. Utilizing one‐pot solvothermal method, we prepared flower‐like CIS‐graphene hybrid (GCIS). Electrochemical tests displayed advantage of graphene with better electron conductivity, and HRP/GCIS showed higher photoelectrochemical behavior.     

COMPREHENSIVE MATHEMATICAL MODEL OF MICROCIRCULATORY DYNAMICS(Ⅱ)—ALCULATION AND THE RESULTS

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｃｏｍｐｒｅｈｅｎｓｉｖｅｍａｔｈｅｍａｔｉｃａｌｍｏｄｅｌｄｅｖｅｌｏｐｅｄｉｎｔｈｅｆｉｒｓｔｐａｒｔｏｆｔｈｉｓｐａｐｅｒ[1]ｃｏｎｔａｉｎｓｄｏｚｅｎｓｏｆｃｏｕｐｌｅｄｅｑｕａｔｉｏｎｓｔｈａｔｆｏｒｍａｌａｒｇｅｎｏｎｌｉｎｅａｒｅｑｕａｔｉｏｎｓｙｓｔｅｍ.Ｈｅｒｅｗｅｃｏｍｂｉｎｅａｎａｌｙｔｉｃａｌａｎｄｎｕｍｅｒｉｃａｌｍｅｔｈｏｄｓｔｏｓｏｌｖｅｉｔａｎｄｄｉｓｃｕｓｓａｎｄａｎａｌｙｚｅｓｏｍｅｉｍｐｏｒｔａｎｔｐｒｏｂｌｅｍｓｉｎｍｉｃｒｏｃ…     

Na3AlF6-Al2O3熔盐体系中ZnFe2O4基阳极的电化学行为

研究了ＺｎＦｅ２Ｏ４基阳极在Ｎａ３ＡｌＦ６－Ａｌ２Ｏ３熔盐体系中的电化学稳定性，讨论了电极的析氧历程并得到了析氧过电位与阳极表观电流密度之间的Ｔａｆｅｌ关系式，η＝０．１２＋０．０５２ｌｏｇｉ（ｉ＝０．０１５－０．４４Ａ／ｃｍ＾２）用三角波电位扫描法测定了电极析氧过程的伏安曲线。     

LC Analysis of Hexafluorophosphate on a Monolithic Column: Application to the Analysis of Ionic Liquids

A silica-based monolithic column with tetrabutylammonium hydroxide–phthalic acid–acetonitrile as mobile phase has been used for LC analysis of hexafluorophosphate with direct conductivity detection. The effects of mobile phase composition, column temperature, and flow rate on retention of hexafluorophosphate were investigated and the optimum chromatographic conditions were selected. Common anions and tetrafluoroborate did not interfere with analysis of hexafluorophosphate. The detection limit (S/N = 3) for hexafluorophosphate was 6.2 mg L^?1. Relative standard deviation (n = 5) for peak area was 0.1%. The method was successfully used for analysis of hexafluorophosphate in ionic liquids.     

低杂波波谱的下移和可近性条件

本文利用改进磁面位移计算的射线轨迹Ｃｏｄｅ，研究在射线轨迹的第圈ｎ的下移以及下移量与各等离子体参量的关系。我们发现等离子体密度越高，波的频度越低，ｎ的下移量越大。计算表明：在射线的第一圈ｎ下移量的最大值大致与ｎ＾－ｅ／「ｆ＾１．５ｑ（ｒｃ）」成正比、也与电流、密度的分布和ｎ的初值等有关。