High pressure studies on new chiral compounds exhibiting TGBA phase

Effects of high pressures on phase sequences of the two homologousn=16 andn=18 of the (3-fluoro-4 ((R) or (S)-methylheptyloxy) 4, (4-fluoro benzoyloxy) tolans) series have been studied. Both compounds exhibit the new twisted Smectic A phase called Twist Grain Boundary TGB_A phase. The high pressure experiments were performed by thermobarometric analysis. The order of the transitions (first or second) have been determined in respect to pressure and temperature. The pressure-temperature phase diagrams show that the TGB_A phase is stabilized by increasing pressure; an inducedN ^* phase appears under high pressure for n=18 leading to the observation of TGB_A-N ^*-I triple point.     

硫化锌精矿氧压酸浸渣中硫和铁的物相存在形式及其含量的测定

利用X射线衍射(XRD)方法分析研究了硫化锌精矿加压酸浸渣的物相存在形式,总结了硫和铁元素的存在形态,根据其相存在形式特点,提出并研究了在硫元素化学物相分析流程中同时测定铁物相的方法。实验表明,硫的相对误差小于5%,各物相有较好的重现性;铁物相分析误差不及硫,但多数小于5%,基本上符合分析测试要求,具有一定参考价值。建立了一种快速、有效表征硫和铁物相的方法,揭示了浸出渣中硫和铁元素赋存状态以及分布状态,为工艺研究、渣相处理以及理论分析提供了一种有效的表征方法。     

基于虚拟相位平面的相位展开方法

在基于相位分析的三维测量系统中,为了准确地得到物体的高度,相位展开扮演着很重要的角色。传统的相位展开方法常常需要额外的投影图,而傅里叶变换轮廓术只需要采集一幅或两幅变形条纹图就可以实现对物体轮廓的测量,其方法速度快,易于实现。针对傅里叶变换轮廓术方法计算得到的截断相位分布,本文提出了一种利用截断相位与参考平面相位差值2π的整数倍数获得截断相位的正确级次,辅助相位展开的方法。当被测物体较复杂,或者相位截断次数较多时,该方法在已有参考平面相位的基础上虚拟新的相位平面,依次比较截断相位和虚拟相位,进行多次分级相位展开,结合多个展开相位结果,最终得到正确的展开相位。该方法展开速度快,展开错误不会蔓延传递。仿真和实物实验结果证明了该方法的可行性,说明该方法可用于傅里叶变换轮廓术中进行截断相位的快速展开。     

Contribution to phase diagram investigation of Pb-In binary system

Experimental results obtained by phase diagram investigation of Pb-In binary system are presented in the paper and compared with literature data. Liquidus and solidus temperatures, as well as cell parameters were determined, and structural analysis of this system was made. Microstructural analysis was done by SEM-EDX, crystallographic analysis was performed by diffractometry, while liquidus and solidus temperatures were determined by DTA. Obtained results show that in investigated system exist three areas: area reach in In, area reach in Pb and separating the intermediate phase (αIn). Experimental results show good agreement with literature. This revised version was published online in July 2006 with corrections to the Cover Date.     

Enrichment of phenols from water with in-situ derivatization by in-tube solid phase microextraction-solvent desorption prior to off-line gas chromatographic determination with large-volume injection

Sorption of phenols from water into the stationary phase of open tubular columns (named in-tube solid phase microextraction) as an enrichment method for gas chromatographic (GC) analysis of aqueous samples was studied. The effect of operating conditions (stationary phase polarity, swelling of the stationary phase by solvents, number of sampling cycles, salting-out effect, sampling velocity, flow rate of desorption solvent) on the process efficiency was evaluated. Real water samples were also used in this study. Swelling of the stationary phase by organic solvent enables the volume of the stationary phase to be increased and its properties to be modified. The use of toluene or tetrachloromethane for the purpose results in high extraction efficiencies for most phenols. The results demonstrated a direct relationship between the extracted amount of phenols and its initial concentration in the sample. The limit of detection in off-line analyses applying large-volume injection was lower than 0.04 μg L⁻¹.These results of the use of in-tube solid phase microextraction with solvent desorption as a non-exhaustive (equilibrium sorptive) enrichment method show a great potential for on-line chromatographic analysis of micropollutants in real water samples.     

Environmental analysis of organic compounds in water using solid phase micro extraction

Solid Phase Micro Extraction (SPME) involves exposing a fused silica fiber coated with stationary phase to a contaminated water sample. The organic analytes become partitioned between the stationary phase and the water and when equilibrium is reached the fiber is removed from the solution and the analytes are thermally desorbed in the injector of a gas chromatograph. The fiber is contained in a syringe to facilitate handling. Factors which affect linear range, limit of detection, and total analysis time are discussed with regard to the development of a method for analysis of volatile compounds in environmental water samples. The sensitivity of the method was determined by the thickness of the film of stationary phase; the equilibration time, however, increased with the film thickness, although it can be minimized by use of a cross-shaped stirrer bar. Increasing the thickness of stationary phase in the analytical column enables the cryofocusing temperature to be increased from ?40 to ?15°C. With an ion trap mass spectrometer, detection limits required by the US Environmental Protection Agency are met for all compounds except chloromethane and chloroethane. The method has been applied to environmental water samples.     

金矿石化学物相分析选择性溶剂实验探索

运用碘-碘化钾氨性溶液作为裸露及半裸露包裹金的选择性溶剂,硫代硫酸钠-亚硫酸钠溶液作碳酸盐包裹金的选择性溶剂,以及溴素-氯化钠溶液作硫化矿包裹金的选择性溶剂进行实验探索.使用国家标准物质GBW07190对方法进行评价,并对该标准物质中其他矿物中金(AAu)的这一相态做了更详细的分离,测定了其中的碳酸盐包裹金、褐铁矿包裹金、黄铁矿包裹金,石英和硅酸盐包裹金的含量.火焰原子吸收法测定金的检出限是0.05×10-6;石墨炉原子吸收法测定金的检出限是0.30×10-9.RSD为0.29%~11.6%,RE为0.11%~8.40%.方法适用于各种金矿物的相态分离,进一步细化了金的各种赋存状态,所得结果令人满意.完全满足矿床划带、选矿试验和成矿规律研究的实际需要.     

我国化学物相分析的进展

对我国化学物相分析的最新成就和进展作了简要评述,内容包括概述、物质相态分析、元素赋存状态分析以及非金属矿物相分析等。引用近十年来的主要文献１００篇。     

A method to prepare gels with controllable morphology through a three‐phase system

Traditional methods for preparing hydrogels with specific morphology need molds with different shapes, which should bring about a complicated process. In order to control the size and morphology of hydrogels conveniently, a new simple synthesis method was advanced to prepare the gels. In this method, the prepolymer solution achieves diffusion in the interface between the upper oil phase and lower hydrogel matrix, which constitutes a three‐phase system, and the morphology of prepared gels was determined by the balanced diffusion status of the prepolymer solution. Hence, through controlling the composition and character of the three different phases in this system, the balanced diffusion status could be adjusted because of the changed interaction acting on the prepolymer solution diffused in the phase interface. The common rule with regards to the resulting morphology of prepared gels was investigated by surface tension analysis. The results prove that this synthetic method is feasible in preparing many kinds of hydrogels with controllable morphology as a common approach.