云纹干涉制栅新技术

本文介绍了两种新的光栅复制技术,它们具有快速、高质量、低成本、操作简单、使用方便、不需特殊仪器等特点.该技术从我国一般力学实验室条件出发,解决了试件栅制作困难,其中漆栅方法可极大地缩短云纹干涉方法的实验周期,该技术也为光栅测试技术的广泛应用提供了方便.     

应用超临界温度氢吸附数据表征活性炭结构

为准确研究氢在活性炭上的吸附平衡,本文对比分析了由氮和氢在活性炭上吸附数据确定的活性炭的孔径分布(PSD)。首先,应用容积法,在0～12.5MPa压力范围、3个温度(113.15K、193.15K、273.15K)下测定氢在K05活性炭上的吸附平衡数据,并由引入系统内氢的质量衡算确定吸附池内氢的总量。其次,以77K氮吸附数据确定的PSD为初值、以吸附池内氢的总量为基准,通过优化非局域密度泛函理论(NDFT)计算值确定活性炭的PSD,进而比较表征介质、温度及平衡压力对PSD的影响。研究表明,应用氢吸附数据表征孔宽小于0.8nm的超细微孔的微分容积较大;平衡压力较高时,由不同温度氢吸附数据确定的超细微孔的PSD相近;孔宽大于1.2nm时,不同温度氢吸附数据确定的PSD间有明显偏差。须应用超临界温度高压氢或氢在亚临界温度区域的吸附数据,同时结合77K氮吸附等温线来表征吸附剂在超细微孔和微孔范围的PSD。     

D201×4树脂对铼(Ⅶ)的交换性能研究

研究了D201×4树脂对铼(Ⅶ)的吸附性能,实验结果表明,在pH=2.7的HAc-NaAc缓冲体系中,静态饱和交换容量为634mg/g树脂;用4.0mol/LNaOH作为解吸剂,一次解吸率达93.5%;等温吸附服从Freundlich经验式;反应开始阶段的表观吸附速率常数k298K=9.58×10-5s-1;反应的△H=-12.10kJ/mol;吸附物中树脂功能基与Re(Ⅶ)的摩尔比约为1:1,并用红外光谱初步探讨了树脂吸附铼的反应机理。     

Determination of captopril in patient human urine using ferrocenemonocarboxylic acid modified carbon nanotubes paste electrode

<正>In this work,we describe a new strategy for the electrochemical determination of captopril(CA) using ferrocenemonocarboxylic acid as a mediator and multiwall carbon nanotubes as sensors in aqueous solution at pH 7.0.The diffusion coefficient(D),and the kinetic parameters such as electron transfer coefficient(α).and heterogeneous rate constant(k_h),for CA were also determined using electrochemical approaches.Under the optimized conditions,the electrocatalytic oxidation peak current of captopril showed two linear dynamic ranges with a detection limit of 0.3×10~(-6) mol L~(-1) captopril.The linear calibration range was 0.8×10~(-6) to 65×10~(-6) mol L~(-1) using cyclic voltammetry.Finally,this modified electrode was also examined as a selective,simple and precise new electrochemical sensor for the determination of captopril in real samples such as drug and patient human urine.     

7-Deazapurines:Synthesis of new pyrrolo[2,3d]pyrimidin-4-onescatalyzed by a Brφnsted-acidic ionic liquid as a green and reusable catalyst

<正>Some new 2-aryl-3,7-dihydro-4H-pyrrolo[2,3-d]pyrimidin-4-ones have been prepared through cyclocondensation of 2-amino 1H-pyrrole-3-carboxamides with aromatic aldehydes followed by air oxidation in the presence of 3-methyl-1-(4-sulfonic acid)butylimidazolium hydrogen sulfate[(CH_2)_4SO_3HMIM][HSO_4],a Br(?)nsted-acidic ionic liquid,as a green and reusable catalyst in solvent-free conditions.     

Cocos nucifera L. water as green corrosion inhibitor for acid corrosion of aluminium in HCl solution

<正>The ability of Cocos nucifera L.water(CW) as non-toxic corrosion inhibitor for acid corrosion of aluminium in 0.5 mol/L HCl has been studied using chemical technique.CW shows significant inhibition as corrosion inhibitor,with 93%efficiency at the highest concentration of the inhibitor.The inhibitive action is attributed to the adsorption of the inhibitor molecules on metal surface following Langmuir adsorption isotherm.     

Lithium bromide catalyzed solvent free method for synthesis of 2-substituted benzimidazoles and imidazopyridines

<正>The first successful lithium bromide mediated solvent free condensation of arylenediamine and esters to obtain 2-substituted benzimidazole and imidazopyridine in good to excellent yields is described.     

Fluorescence quenching method for the determination of catechol with gold nanoparticles and tyrosinase hybrid system

<正>The determination method of catechol by fluorescence quenching was developed.The assay was based on the combination of the unique property of gold nanoparticles with tyrosinase enzymatic reaction.In the presence of tyrosinase,the fluorescence of gold nanoparticles was quenched by catechol which can be employed to detect catechol.Under the optimal conditions,a linear range 5.0×10~(-7)-1.0×10~(-3) mol L~(-1) and a detection limit 1.0×10~(-7) mol L~(-1) of catechol were obtained.o-Quinone intermediate produced from the enzymatic catalyzed oxidation of catechol was considered to play the main role in the fluorescence quenching.     

Oxidation of propane over ammonium-transition metal mixed keggin phosphomolybdate salts

Mixed ammonium-transition metal salts with formula of (NH4)xMyHzPMo12O40 (M = Ni2+, Co2+ or Fe 3+) denoted as MPMo12 have been investigated for the oxidation of propane, with molecular oxygen, at temperature range between 380℃ and 420℃ after in-situ pre-treatment performed at two heating rate of 5 or 9℃/min. They were characterized by BET method, XRD, UV-Vis and IR techniques. The catalysts were found to be active in the propane oxidation and selective to propene or acrolein, in particular for samples pre-t...     

Kinetic models of natural gas combustion in an internal combustion engine

In this study, combustion of methane was simulated using four kinetic models of methane in CHEMKIN 4.1.1 for 0-D closed internal combustion (IC) engine reactor. Two detailed (GRIMECH3.0 & UBC MECH2.0) and two reduced (One step & Four steps) models were examined for various IC engine designs. The detailed models (GRIMECH3.0, & UBC MECH2.0) and 4-step models successfully predicted the combustion while global model was unable to predict any combustion reaction. This study illustrated that the detailed model sh...