NMR AND DFT STUDY OF Co-C BOND ACTIVATION MECHANISM IN VITAMIN B_(12) COMPOUNDS

This report focuses on a theoretical study of the cobalt-cabon bond activation mechanism in Vitamin B12, its co enzyme complexes, and model compounds such as cobalamins (Cbl), cobaloximes and cobalt porphyrins. In particular, emphasis is placed on the nucleotide loop and its role in the base on and base off mechanism.     

NO在Er2O3/Bi2O3催化剂上的程序升温分解

NOx是造成大气污染的化学物质之一,因此,消除NOx是环境保护的一项重要任务,目前比较成熟的消除NOx工艺是用氨为还原剂和V2O5/TiO2为催化剂的选择催化还原(SCR)法[1],但其成本过高.     

10 ps High Power Laser System at 248 nm

A simple 10 ps KrF laser system consisting of quenched dye laser oscillator pumped by a XeCl laser, a distributed feedback dye laser (DFDL), a three-stage dye amplifier and a two-stage KrF amplifier are described. The output of the laser system is 140 mJ with 10 ps pulse width by using polarization-multiplexing amplification. A focused output laser intensity of about 4×1015 W/cm2 is obtained. The saturation fluence for KrF laser is obtained with this laser.     

Rh多晶表面CO2还原过程的电化学和原位FTIR反射光谱研究

应用程序电位扫描法和电化学原位FTIR反射光谱从定量角度在分子水平 上研究了CO2在Rh电极上的电催化还原性能。红外光谱结果指出CO2还原的吸附产物为线型和桥式吸附态CO物种。在所研究和还原电位范围（－0．15－0．40V）和相同还原时间,CO2还原吸附物种的氧化电量随还原电位的负移而增大,在每个还原电位下,时间超过250s时都可达到一个相应的饱和值。原位红外光谱和电化学研究结果表明,CO2的还原与Rh电极表面氢吸附反应密切相关,同时需要一定数量相邻表面位的参与。因此生成的CO不能在Rh电极表面达到满单层吸附,而是形成均匀的亚单层分布。     

原料气中添加CO对CO_2在铜基催化剂上加氢反应的促进作用(英文)

研究了CO2在Cu－Zn－Al催化剂上的加氢合成甲醇反应。发现在原料气中添加少量的CO可提高甲醇的选择性和收率。TPD和TPSR结果表明,CO占据催化剂表面部分活性位并抑制CO2的逆水煤气转换,促进了甲醇的生成。     

A GROUP OF EXACT (3+1) DIMENSIONAL CYLINDRICALLY SYMMETRIC WAVE SOLUTIONS TO THE EINSTEIN GRAVITATIONAL FIELD EQUATION

Starting with the diagonal spacetime metric tensor, the Einstein gravitational field equation is solved, and a set of exact (3+1) dimensional cylindrically symmetric wave solutions with two arbitrary functions are found. In these solutions all nonvanishing components of spacetime metric tensor are varying with the same propagating factor (ct-z) while the waves are travelling along z axis. The physical picture and the condition of positive energy density of the wave solutions are discussed.     

Microwave-assisted dilute acid pretreatment of different agricultural bioresources for fermentable sugar production

Microwave-assisted pretreatment can be used for fermentable sugar production from lignocellulosic biomass. In this study, the optimum hydrolysis conditions of barley husk, oat husk, wheat bran, and rye bran were determined in power level, treatment time, solid-to-liquid ratio and dilute acid ratio as follows: 700 W, 6.92 min, 1:18.26 w/v, and 3.67% for barley husk, 600 W, 6.96 min, 1:17.22 w/v, and 3.47% for oat husk, 600 W, 6.92 min, 1:16.69 w/v, and 1.85% for wheat bran, and 460 W, 6.15 min, 1:17.14 w/v, and 2.72% for rye bran. The fermentable sugar concentrations were 37.21 (0.68 g/g), 38.84 (0.67 g/g), 49.65 (0.83 g/g), and 36.27 g/L (0.62 g/g) under optimum conditions, respectively. The results showed that microwave-assisted pretreatment is a promising technology which can be successfully implemented for the hydrolysis of lignocellulosic biomass for high sugar yield. On the other hand, hydrolysates included some inhibitors such as organic acids, furans, and phenolic compounds. Lignocellulosic biomass used in this study can be employed as good feedstocks for value-added product production in the fermentation process, after the inhibitors have been detoxified/removed with different detoxification methods.     

An Electrochemical DNA Biosensor for the Detection of the Apa I Polymorphism in the Vitamin D Receptor Gene Using Meldola's Blue as a Hybridization Indicator

Electrochemical detection of nucleic acid base mismatches related to Apa I single nucleotide polymorphism (SNP) in the vitamin D receptor gene was performed successfully using 7‐dimethyl‐amino‐1,2‐benzophenoxazinium salt (Meldola's blue, MDB) with 10.9 pmol/100 μL of detection limit. MDB reduction signals obtained from probe, mismatch(probe‐SNP containing target) and hybrid(probe‐target) modified pencil graphite electrode(PGE) increased respectively. The sensor was able to clearly distinguish perfect match from mismatch DNA in a 30 min. detection time. Several factors affecting on the hybridization and indicator response are studied to maximize sensitivity and selectivity. The advantages of the biosensor are discussed in comparison with previous electrochemical assays for DNA hybridization.     

Green’s function,temperature in a convectively cooled sphere with arbitrarily located spherical heat sources

Steady state heat conduction in a convectively cooled sphere having arbitrarily located spherical heat sources inside is treated with the method of Green’s function accompanied by a coordinate transform. Green’s function of the heat diffusion operator for a finite sphere with Robin boundary condition is obtained by spherical harmonics expansion. Verification of the analytical solution is exemplified in some generic cases related to the pebbles of South-African PBMR as of year 2000 with 268 MW thermal power. Analytical results for different sectors of the sphere (pebble) are compared with the results of computational fluid dynamics code FLUENT^™. This work is motivated through a modest effort to assess the stochastic effects of distribution and volumetric effects of fuel kernels within the pebbles of future-promising pebble bed reactors.     

La2NiO4／Al2O3催化剂上CH4／CO2的重整

 通过溶胶－凝胶方法制备了尖晶石结构的La2NiO4／Al2O3催化剂，采用BET，XRD和TG表征了催化剂的孔分布、比表面积、体相组成以及凝胶样品的热失重和热分解过程．将催化剂应用于CH4／CO2重整反应制合成气，考察了惰性气体和反应温度对转化率、选择性以及积碳的影响．结果表明，在高空速（GHSV＝4．8×104ml／（g·h））下，CH4和CO2转化率分别为51％和60％，CO和H2的选择性约为98％和92％，惰性气体He的引入明显地提高了CH4和CO2的转化率．