等度高效液相色谱测定大豆异黄酮中大豆甙元和金雀异黄酮

本文介绍了等度高效液相色谱(HPLC)测定大豆异黄酮中二种主要成份:大豆甙元(Daidzein)和金雀异黄酮(Genistein)的方法。采用Atlantis C18色谱柱和EasyGuard C18,保护柱;以甲醇:0·1%醋酸(pH3·11)=51·5:48·5(v/v)为流动相;检测波长λ=254nm;流速1mL/min。在测定范围内(10-200ng)峰面积与质量浓度线性关系良好。大豆甙元和金雀异黄酮的相关系数分别为0·9984,0·9997·两组份回收率为97·0—102·92%·     

偶氮胂Ⅲ褪色光度法测定铬

在6mol·L~(_1)HNO_3介质中,Cr(Ⅵ)与偶氮胂Ⅲ进行氧化褪色反应,该褪色反应的表现摩尔吸光系数∑_(523nm)=3.7×10~5L·mol~(-1)·cm~(-1)。铬(Ⅵ)在0～1.8×10~(-4)g/L范围内符合比尔定律。本法用于土样中痕量铬的测定,结果满意。     

反相高效液相色谱法同时测定洁康舒洗剂中三组分的含量

建立反相高效液相色谱法同时测定洁康舒洗剂中大黄酸、大黄素和大黄酚含量的方法。采用反相高效液相色谱法。symmctry C18柱(3.9×150mm,5μm)流动相为甲醇—水—磷酸(80:20:0.1);流速为1.0mL·min-1;检测波长为432nm。大黄酸、大黄素和大黄酚的回归方程分别为:C1=7.3159×10-1+1.8966×10-5A,r=9994,C2=1.0513+1.5680×10-5A,r=0.9999C3=1.2260-1.4684×10-5A,r=0.9999三者分别在7.60~38.0μg·mL-1、1.75~8.75μg·mL-1、2.4~12.OOμg·mL-1范围内呈线性关系。平均回收率和RSD分别为98.02%、96.63%、97.05%和1.78%、1.20%、1.15%。该方法操作简便,测定结果准确可靠,可用于测定洁康舒洗剂中大黄酸、大黄素和大黄酚的含量。     

微分脉冲极谱法测定饮料的总酸量

本文采用微分脉冲极谱法于浓度为0.5mol·L~(-1)的KCl底液,5.84×10~(-4)mol·L~(-1)的柠檬酸标准液,pH为5.65,CdCO_3粉末加入量为0.2g,通N_27min的条件下测定饮料中的总酸量。本法的线性方程为y=9.0288x+0.4192,线性浓度范围1.2×10~(-5)～8.4×10~(-5)mol/L,相关系数R=0.9995,标准偏差为0.142,测定结果与中和滴定法和电位滴定法对比,表明微分脉冲极谱法可以简单、快速、准确测定饮料中的总酸量。     

反相高效液相色谱法测定肾康口服液中黄柏的小檗碱含量

建立反相高效液相色谱法测定肾康口服液中黄柏的小檗碱含量。采用反相高效液相色谱法,Novapak C18柱(3.9×150mm,5μm)流动相为甲醇一乙腈(0.05mol·L-1)-磷酸二氢钠溶液(20∶3S∶45),流速为1.0mL·min-1,检测波长为346nm。小檗碱的回归方程为C=1.2616+1821X10-6A,r=0.9992,在4.00~20.00μg·mL-1范围内呈线性关系。平均回收率和RSD分别为101.32%和1.18%(n=5)。方法操作简便,测定结果准确可靠,可用于测定肾康口服液中黄柏的小檗碱含量。     

分光光度法测定芦荟中铁含量的研究

本文研究了Fe(Ⅱ)—phen—CTMAB—酒石酸氢钾体系测定铁离子含量分光光度法,最大吸收波长515nm,Fe(Ⅲ)含量在0.5～8μg/ml内符合比耳定律,相关系数r=0.9995,摩尔吸光数ε=1.23×10~4L·mol~(-1)·cm~(-1).利用该方法测定库拉索芦荟含铁量,RSD小于0.54％(n=6),回收率98.1％～101.5％。     

用于非制冷热释电红外探测器的 PZT铁电薄膜研究

采用溶胶-凝胶和射频磁控溅射相结合的方法制备了PZT铁电薄膜．用溶胶-凝胶法制备一层PZT薄膜作为籽晶层,在衬底PZT(seed layer)／Pt／Ti／SiO2／Si上用射频磁控溅射过量10％Pb的Pb(ZrxTi1-x)O3(x=0．3)陶瓷靶生长厚500nm的PZT铁电薄膜．采用在450℃预退火,575℃后退火的快速分级退火方法对PZT铁电薄膜进行热处理．PZT铁电薄膜获得了较好的热释电性能,热释电系数、介电常数、介电损耗和探测度优值因子分别为P=2．3×10-8C·cm-2·K-1,ε=500,tanδ=0．02,Fd=0．94×10-5Pa-0.5．     

碳纤维(LCF)-无宏观缺陷(MDF)水泥基复合材料电学性能的研究

本文研究了碳纤维(LCF)-无宏观缺陷水泥(Macro-Defect-Free Cement)基复合材料的电阻率 ρ、随 LCF 体积分数的变化规律。结果表明,当 LCF 体积分数由5%增加至50%时,该材料的 lgρ_v 由10Ω·cm 下降到10~(-1)Ω·cm 数量级。体积分数为23%时出现了渗滤阈值(Pecolation Threshold)现象。通过分析认为该材料的导电机制为隧道导电。另外测定了该材料电磁屏蔽效率 S。得到在400—1600MHz 频率范围内,对电磁波具有10—40dB 良好的衰减效果。     

SCR直接光度法测定镁合金中微量铍

在 pH =9 6的溶液中 ,以乙二胺四乙酸二钠 (EDTA)和酒石酸钠为掩蔽剂 ,铍 (Be)与铬天青R (SCR)、溴化十六烷基三甲基胺 (CTMAB)形成三元络合物。在波长 5 5 8nm处有最大吸收 ,摩尔吸收系数ε为 3 0 6× 10 4L·mol-1·cm-1,铍量在 0～ 5 0 0 μg/ 10 0mL范围内 ,服从比耳定律 ,方法准确、可靠 ,有很好的选择性。适用范围为含铍 0 0 0 0 5 %～ 0 0 0 5 0 %。样品回收率可达 10 0 % ,适用于镁合金中微量铍的测定     

胶束电动毛细管色谱法测定冬虫夏草中核苷及核苷碱基的含量

目的:测定冬虫夏草、虫体和子座部分核苷及核苷碱基的含量,为质量评定提供检测方法。方法:用胶束电动毛细管色谱法(MECC)测定,以黄嘌呤核苷为内标,电泳缓冲液为V(20mmol·L~(-1)硼砂,25mmol·L~(-1)十二烷基硫酸钠即SDS):V(乙腈)=95:5,电压25KV,柱温30℃,检测波长260nm,进样量5mmHg·S。结果:可同时测定出腺嘌呤(Ⅰ)、腺苷(Ⅱ)、次黄嘌呤(Ⅲ)、鸟苷(Ⅳ)、尿苷(Ⅴ)和次黄嘌呤核苷(Ⅵ)的含量,回收率分别为102.5％,102.7％,98.83％,101.1％,100.8％和101.4％,RSD小于2％。结论:正品虫草中都含有1～Ⅵ6个化合物,子座中Ⅰ～Ⅴ5个化合物的含量均明显高于虫体,虫草中Ⅱ、Ⅳ、Ⅴ、Ⅵ4种核苷的含量较高且相对稳定。     

金属—PAN—S配合物的极谱研究——Ⅱ:Fe~(3+)—PAN—S—TEA—NH_3·H_2O—NH_4Cl体系配合吸附波

在NH_3·H_2O—NH_4Cl—三乙醇胺底液中Fe(Ⅲ)与PAN—S产生一灵敏的配合吸附波,峰电位在—0.50伏(vs.SCE)。峰电位与铁离子浓度在2.8×10~8～3.4×10~(-6)mol/L范围内线性良好,检出下限可达2.8×10~(-8)mol/L。该法用于乳粉、头发、血清等样品的测定,结果满意。     

Meso—四—(4—甲基,3—磺基苯基)卟啉分光光度法测定葡萄糖酸锌含量

本文研究了在抗坏血酸存在下TTPS_4与Zn(Ⅱ)的显色反应。结果表明:在PH为4.40的NaAc—HAc缓冲体系中,以抗坏血酸和吐温—60为辅助配位剂,在沸水浴中加热8分钟,Zn(Ⅱ)与TTPS_4即形成稳定的高灵敏度配合物,最大吸收波长位于430 nm,ε_(430)=5.5×10~5。Zn(Ⅱ)浓度在0～0.120μg/ml范围内遵守比耳定律。应用此法直接测定补锌口服液葡萄糖酸锌含量,结果满意。     

Dielectrical and structural characterization of iron oxide added to hydroxyapatite

In this work we report preparation, structural and dielectric analyses of iron oxide added in hydroxyapatite bioceramic (Ca₁₀(PO₄)₆(OH)₂ — HAP). Hydroxyapatite is the main mineral constituent of teeth and bones with excellent biocompatibility with hard and muscle tissues. The samples were prepared through a calcination procedure associated with dry high-energy ball milling process with different iron concentrations (1, 2·5 and 5 wt%). The dielectric analyses were made measuring the sample impedance in the frequency range 1 kHz–10 MHz, at room temperature. The relative permittivity of the ceramics, at 10 MHz, are between 7·13 ± 0·07 (1 wt%) and 6·20 ± 0·11 (5 wt%) while e ⁿ are between 0·0795 ± 0·008 (1 wt%) and 0·067 ± 0·012 (5 wt%). These characteristics were related to the sample microstructures studied by X-ray diffraction and SEM.     

偶氮氯膦——mA分光光度法测定钢样及食盐中钡

在pH9.0的NH_3—NH_4Cl缓冲溶液中,Ba(Ⅱ)与间乙酰基偶氮氯膦(CPAmA)生成紫蓝色络合物。络合物的最大吸收位于635nm。络合物的组成Ba(Ⅱ):CPAmA为1∶4,表现摩尔吸光系数ε_(max)=1.95×10~41·mol~(-1)·cm~(-1),钡(Ⅱ)含量在0-3.2×10~(-3)g/L范围内遵守比尔定律。本法用于测定钢样及食盐中的钡,结果满意。     

Synthesis of hydrophobic aerogels for transparent window insulation applications

Abstract

The present paper deals with the synthesis of hydrophobic aerogels using methyltrimethoxysilane (MTMS) as a hydrophobic agent for transparent window insulation applications. The molar ratio of methanol (solvent), water, and ammonia (catalyst) to the tetramethoxysilane (precursor) MeOH/H₂O/NH₄OH/TMOS was fixed at 12/4&/3·6×10^-3/1 throughout the experiments and the MTMS/TMOS molar ratio M was varied from 0 to 1·55. After gelation, the alcogels were dried supercritically using the high temperature alcohol method. It has been found that lower (<0·26) M values resulted in highly transparent (optical transmission >90% for a 10 mm thick sample at 800 mm wavelength) and negligible volume shrinkage (<2%) but less hydrophobic aerogels whereas higher (>1·03) M values resulted in semitransparent (<20% optical transmission of 800 nm for a 1 cm thick sample) aerogels with >10% volume shrinkage but excellent hydrophobicity. A good compromise of acceptable optical transmittance (～85% optical transmission at 800 nm for a 1 cm thick sample), hydrophobicity with 42 kg m^-3 bulk density, and negligible volume shrinkage were obtained at M≈0·70. Hydrophobicity of the aerogels was tested by measuring the contact angle between a water droplet and the aerogel surface. The aerogels were characterised by infrared spectroscopy, bulk density, optical transmittance, and thermal conductivity measurements.     

Arsenic removal by electrocoagulation using combined Al-Fe electrode system and characterization of products

Combination of electrodes, such as aluminum and iron in a single electrochemical cell provide an alternative method for removal of arsenic from water by electrocoagulation. The removal process has been studied with a wide range of arsenic concentration (1–1000 ppm) at different pH (4–10). Analysis of the electrochemically generated by-products by XRD, XPS, SEM/EDAX, FT-IR, and Mössbauer Spectroscopy revealed the expected crystalline iron oxides (magnetite (Fe₃O₄), lepidocrocite (FeO(OH)), iron oxide (FeO)) and aluminum oxides (bayerite (Al(OH)₃), diaspore (AlO(OH)), mansfieldite (AlAsO₄·2(H₂O)), as well as some interaction between the two phases. The amorphous or very fine particular phase was also found in the floc. The substitution of Fe³⁺ ions by Al³⁺ ions in the solid surface has been observed, indicating an alternative removal mechanism of arsenic in these metal hydroxides and oxyhydroxides by providing larger surface area for arsenic adsorption via retarding the crystalline formation of iron oxides.     

火焰原子吸收光谱法测定孕多维胶囊中钙、铁和锌的含量

用火焰原子吸收光谱法测定孕多维胶囊中钙,铁和锌的含量。结果表明,钙在8～16μg·mL~(-1)浓度范围,锌在0.5～3.5μg·ml~(-1)浓度范围,铁在3～11μg·mL~(-1)浓度范围内呈线性。钙,铁和锌的平均回收率分别为99.3％(RSD=0.93％),102.2％(RSD=0.57％)和100.6％(RSD=1.18％)。该方法快速、灵敏、准确,样品处理简便易行,可用于药品的质量控制。     

Effect of cerium sulphide particle dispersions on acicular ferrite microstructure development in steels

Abstract

Of the phases found in wrought steels, cerium sulphide particles are notable in that they can be both stable at liquid metal temperatures and exhibit good lattice coherency with α iron. An investigation has been carried out to determine the effectiveness of cerium sulphide particle dispersions in nucleating intragranular acicular ferrite microstructures in steels. Vacuum melts of 50 kg have been manufactured of appropriate base steel compositions with varying additions of cerium (0·04–0·18%) and sulphur (0·01–0·04%). The work has shown that 0·02–0·12% cerium and 70–340 ppm sulphur may be retained in steels after deoxidation and desulphurisation reactions while oxygen can be reduced to <20 ppm. Resulting inclusions are largely spheroidal in shape and consist of several crystalline compounds, notably CeS, Ce₃S₄ and Ce₂O₂S. The inclusion numbers are of the order of 0·68–6·12 × 10⁶ mm^?3 with mean diameters of 0·63–1·70 μm. The densities of these inclusion dispersions are approaching those in weld metals where acicular ferrite is the dominant microstructure constituent. Significant volume fractions of acicular ferrite (up to 65%) have been obtained in steels after thermally cycling in a dilatometer and cooling at rates simulating transformation conditions ranging from high heat input welding to air cooling of forgings and water cooling of plate. A potential beneficial effect of acicular ferrite on mechanical properties in high heat input welding (heat affected zone grain refinement) and in thermo-mechanically processed steels (relaxed schedules) has been highlighted. A pilot plant billet cast of steel has shown the feasibility of achieving the required particle dispersions and acicular ferrite microstructure in tonnage steelmaking.