Chemical stability of hydroxysulphate green rust synthetised in the presence of foreign anions: carbonate, phosphate and silicate

Hydroxysulphate green rust species were precipitated in the presence of various anions. is stable at ∼pH 7 and is transformed into a mixture of magnetite and ferrous hydroxide when the pH raised at ∼12. In the presence of carbonate species, is partially transformed into a mixture of magnetite and siderite at ∼pH 8.5. This transformation is stopped when silicate anions are present in the solution. As already observed for phosphate anions, the adsorption of silicate anions on the lateral faces of the crystals may explain this stabilization effect. Sulphate anions are easily exchanged by carbonate species at ∼pH 10.5. In contrast, anionic exchange between sulphate and phosphate anions was not observed.     

Metals in water and surface sediments from Henan reaches of the Yellow River,China

The concentrations of Cd,Cr,Cu,Ni,Pb and Zn were determined in the water and surface sediments from the Henan reaches of the Yellow River.Twenty-three sampling sites along the Yellow River and its tributaries were selected.Generally,metal concentrations were found to decrease in sequences of Zn>Cu>Pb>Cr>Ni>Cd in water and Zn>Cr>Pb>Ni>Cu>Cd in sediments.High levels of metal concentration were determined at a few stations of the river and its tributaries,such as Yiluo River,Si River and Qin River.The pollutio...     

Polymerization of molecular (yellow) arsenic

DTA studies were performed to investigate the polymerization of molecular (yellow) arsenic (y-As), in the dark and also under illumination/irradiation. The semiempirical quantum chemical CNDO/BW method for calculating the dimerization reaction pathway of two As₄ molecules was applied, and showed that the stability of y-As decreases, due to the formation of stable fragments of the polymeric phase (a-As). Using the principle of orbital symmetry conservation, it was shown that polymerization takes place most favourably from a staggered “face-to-face” configuration of As₄ molecules. Dark polymerization proceeds under activation. For a result of the initial stage of polymerization, CNDO/BW simulation predicts the formation of an As₈ dimer. The molecular cluster As₈ of D_2h symmetry forms a six-membered chairshaped ring which constitutes one of the dominating units in the polymeric phase (a-As).     

LD-pumped Nd:YAG/LBO 556 nm yellow laser

A new laser transition at 1112 nm was obtained after analyzing the parameters of the main laser transitions in Nd:YAG and calculating the transmission loss of the cavity at 1064, 1319, and 946 nm. The maximum output power of the fundamental wavelength was 610 mW, the fundamental wavelength light-to-light conversion efficiency was 38.1%, the maximum output at 556 nm was 109 mW intra-cavity frequency doubled by LBO, the SHG conversion efficiency was 17.8%, and the overall light-to-light efficiency was 6.8% for the pump power of 1.6 W.     

紫外分光光度法同时测定柠檬黄和日落黄

采用紫外分光光度法同时对饮料中柠檬黄、日落黄两种食用合成色素进行测定,确定了各色素的最大吸收波长λmax,及其最大吸收波长处的吸收系数a和摩尔吸收系数ε.结果表明:柠檬黄在λmax=426nm处的吸收系数为a=33.45 L·g-1,摩尔吸收系数为ε=1.79×104L·mol-1·cm-1.日落黄在λ=481nm处的吸收系数为a=34.00 L·g-1·cm-1,摩尔吸收系数为ε=1.54×104L·mol-1.cm-1.测定饮料中柠檬黄、日落黄含量分别为0.0067mg/mL,和0.0033mg/mL,相对标准偏差(RSD)分别为0.148%、1.026%,测定了两种色素在奥地利饮料中的回收率分别为:92.35%、96.77%.该方法操作简便,同时准确度高,精密度好.     

LD抽运Nd∶YVO4自喇曼倍频黄光激光器

报道了LD抽运的自喇曼c切Nd∶YVO4调Q腔内倍频黄光激光器.Nd∶YVO4晶体同时作为激光介质和喇曼晶体，通过声光调Q技术，产生了1 178.7 nm的喇曼激光，经过KTP腔内倍频，输出589.4 nm黄光.测量了平均输出功率随抽运功率和脉冲重复率的变化.典型的1 066.7 nm基频光、1 178.7 nm喇曼光和589.4 nm倍频光的脉冲宽度分别为24.9 ns、11.2 ns和6.8 ns.在脉冲重复率为15 kHz，抽运功率为7.56W时，产生了平均功率为151 mW的589.4 nm光的输出.     

Recent Research and Development in Solving Atmospheric Corrosion Problems of Steel Industries in Japan

A rust layer, so called protective rust layer, on a weathering low-alloy steel has strong protective ability for atmospheric corrosion of the steel. We have recently found through a large number of spectroscopic studies including Mössbauer spectroscopy that the protective rust layer forms after long-term phase transformation. The phase and structure of the rust definitely control the protective ability of the rust layer. From this recent knowledge, some new technologies have been developed. One is the surface-treatment technique that provides a possibility for obtaining the protective rust layer in a relatively short period even in the severe environments such as in marine and chloride (de-icing salts) containing environments. Others are based on selection of effective alloying elements for steel materials. These are particularly important for application in areas where protective rust layer formation may be hindered or prevented. In this paper, we mention recent progress in research and development on rusting protection by rust for atmospheric corrosion of steels in Japan.     

波浪载荷导致黄河口潮坪沉积物垂向运移现场观测研究

2005年8月7~8日,现代黄河三角洲刁口地区经历了一次由台风"麦莎"引起的风暴潮过程。通过对比分析风暴潮前后受保护潮坪滩面沉积物的粒度特征变化情况,发现了风暴潮期间在强烈的波浪载荷导致的渗流作用下,粉质土海床出现了极细粉粒由下向上运移并输出滩面的现象。结合现场试验期间采集到的孔隙水压力监测数据,本文基于海床动力响应的观点分析了其成因机制。     

Synthesis and Characterization of A Small Molecule CFTR Chloride Channel Inhibitor

A thiazolidinone CFTR inhibitor (CFTRinh-72) was synthesized by a three-step procedure with tri-fluromethylaniline as the starting material. The synthesized CFTR inhibitor was characterized structurally bymeans of ^1H NMR and functionally in a CFTR-expressing cell line FRT/hCFTR/EYFP-H148Q by both fluo-rescent and electrophysiological methods. A large amount(100g) of high-quality small molecule thiazolidi-none CFTR chloride channel inhibitor, CFTRinh-72, can be produced with this simple three-step synthetic pro-cedure. The structure of the final product 2-thioxo-3-(3-trifluromethylphenyl )-5-[4-carboxyphenyl-methylene]-4-thiazolidinone was confirmed by ^1H NMR. The overall yield was 58% with a purity over 99%as analyzed by HPLC. The synthesized CFTRinh-72 specifically inhibited CFTR chloride channel function in acell-based fluorescence assay(Kd≈1.5μmol/L) and in a Ussing chamber-based short-circuit current assay(Kd≈0. 2μmol/L), indicating better quality than that of the commercial combinatorial compound. The syn-thesized inhibitor is nontoxic to cultured cells at a high concentration and to mouse at a high dose. The syn-thetic procedure developed here can be used to produce a large amount of the high-quality CFTRinh-72 suitablefor antidiarrheal studies and for creation of cystic fibrosis models in large animals. The procedure can be usedto synthesize radiolabled CFTRinh-72 for in νiνo pharmacokinetics studies.     

南瓜黄色素阻断亚硝胺合成与抑菌活性研究

在模拟人体胃液条件(pH=3.0,温度37℃)下,研究了南瓜黄色素阻断亚硝胺合成和清除亚硝酸盐的能力,并与常用抗氧化剂2,6-二叔丁基对甲酚(BHT)进行了比较。同时采用滤纸片法测定了南瓜黄色素的抑菌活性。结果表明,南瓜黄色素具有较强的阻断亚硝胺合成和清除亚硝酸盐能力,其对亚硝胺合成的阻断率最大可达93.58%,对NaNO_2清除率为71.56%,但其阻断亚硝胺合成能力和清除亚硝酸盐能力明显弱于常用抗氧化剂BHT。同时,实验表明,南瓜黄色素具有较强抑菌活性,其对供试菌种的抑制能力大小顺序为:大肠杆菌金黄色葡萄球菌枯草芽孢杆菌。