Conversion of natural gas to C_2 hydrocarbons through dielectric-barrier discharge plasma catalysis

The experiments are carried out in the system of continuous flow reactors with dielectric-barrier discharge (DBD) for studies on the conversion of natural gas to C2 hydrocarbons through plasma catalysis under the atmosphere pressure and room temperature. The influence of discharge frequency, structure of electrode, discharge voltage, number of electrode, ratio of H2/CH4, flow rate and catalyst on conversion of methane and selectivity of C2 hydrocarbons are investigated. At the same time, the reaction process is investigated. Higher conversion of methane and selectivity of C2 hydrocarbons are achieved and deposited carbons are eliminated by proper choice of parameters. The appropriate operation parameters in dielectric-barrier discharge plasma field are that the supply voltage is 20-40 kV (8.4-40 W), the frequency of power supply is 20 kHz, the structure of (b) electrode is suitable, and the flow of methane is 20-60 ml · min-1. The conversion of methane can reach 45%, the selectivity of C2 hydrocarbons i     

Formation and Aggregation Kinetics of Mixed Metal Hydroxides Agglomerates

The aggregation and fractal structure of mixed metal hydroxides ( MMH ) agglomerates with increasing ionic strength have been studied by dynamic light scattering ( DLS ) and SEM techniques. The experiments indicate that the MMH agglomerates have two different structures in RLA regime and DLA regime, and also give the proof that the transition region between RLA and DLA may occur.     

Synthesis, Dimeric Crystal Structure, and Biological Activities of N-(4-Methyl-6-oxo-1,6-dihydro-pyrimidin-2-yl)-N′-(2-trifluoromethyl-phenyl)-guanidine

IntroductionPlants have a more extensive biosynthetic capacitythan animals, which is attributed to the fact that ani-mals rely on their diet for the supply of many biochemi-cal compounds and their precursors. Owing to thisdifference, plants contain numero…     

周期极化KTP晶体光参量振荡特性研究

基于较新的Sellmeier方程,研究了周期极化钛氧磷酸钾(KTiOPO₄简称KTP)晶体光参量振荡的容差特性,给出了极化反转光栅周期、晶体温度及泵浦光波长的调谐曲线和带宽的容差特性曲线,并与PPLN晶体作了比较数值计算结果与已有实验数据吻合较好.     

A Modified Chitosan Adsorbent for Selective Removal of Low Density Lipoprotein

A modified chitosan adsorbent was synthesized through a simple preparation procedure,and it demonstrated good adsorption performance for selective removal of low density lipoprotein in human plasma. Phase inversion technique was employed to form chitosan beads, to which epoxy groups were then introduced by reacting with ethyleneglycol diglycidylether, and tryptophan was subsequently coupled to the epoxy-activated beads.     

垂直腔面发射激光器电、光特性分析

根据增益波导垂直腔面发射激光器(VCSELs)直接耦合的准三维理论模型,通过有限差分法对泊松方程、注入电流密度、载流子浓度和光场分布方程求自洽解,研究了垂直腔面发射激光器的电特性和光波导特性.计算结果表明,氧化限制层位置是影响激光器特性的主要因素之一,如果忽略N型DBR层的影响,将与实际的垂直腔面发射激光器有较大偏差.     

The setereoselective preparation ofβ-keto esters using baker's yeast in the presence of rice wine koji

By the addition of rice wine koji,enhancement of the reactivity was observed for the baker's yeast reduction ofβ-keto esters into (S)-β-hydroxy esters with high enantiomeric purity (73-98%).     

Thermal Degradation Kinetics of N,N＇-Di（diethoxythiophosphoryl）-1,4-phenylenediamine

The non-isothermal degradation kinetics of N,N＇-di（diethoxythiophosphoryl）-1,4-phenylenediamine in N2 was studied by TG-DTG techniques.The kinetic parameters,including the activation energy and pre-exponential factor of the degradation process for the title compound were calculated by means of the Kissinger and Flynn-Wall-Ozawa（FWO）method and the thermal degradation mechanism of the title compound was also studied with the Satava-Sestak methods.The results indicate that the activation energy and pre-exponential factor are 152.61 kJ/mol and 9.06×101 4s -1with the Kissinger method and 154.08 kJ/mol with the Flynn-Wall-Ozawa method,respectively.It has been shown that the degradation of the title compound follows a kinetic model of one-dimensional diffusion or parabolic law,the kinetic function is G（α）=α2and the reaction order is n=2.     

Syntheses and Structures of Binaphthyl-bridged Schiff Bases

The reaction of dinaphthofuran with lithium in anhydrous diethyl ether led to a solution of the corresponding C,O-dilithiated intermediate which, upon treatment with DMF at ？78 oC, afforded, after hydrolysis, 2＇-hydroxy-1,1＇-binaphthyl-2-carbaldehyde in a good yield. Then binaphthyl-bridged Schiff bases were prepared by the condensation of 2＇-hydroxy-1,1＇-binaphthyl-2-carbaldehyde with the corresponding aromatic amines.     

Bioaccumulation and single and joint toxicities of penta-BDE and cadmium to earthworms (Eisenia fetida) exposed to spiked soils

Bioaccumulation of penta-BDE(DE-71) in earthworms(Eisenia fetida) and the induced toxicities on the growth and reproduction of earthworms were investigated.All the major congeners in DE-71 could be bioaccumulated in earthworms and the concentration found in earthworms correlated to the spiked concentration in soil.DE-71 might inhibit the growth and reproduction of cocoons and juveniles of earthworms.The toxicities were dose dependent and increased with exposure time.Exposing earthworms to combination of DE-...