2,3,7-三羟基-9-水杨基荧光酮分光光度法测定痕量铌

以酒石酸作为辅助络合剂,在表面活性剂溴化十六烷基吡啶存在下及pH 5.5的乙酸-乙酸钠缓冲溶液中,显色剂2,3,7-三羟基-9-水杨基荧光酮与铌(Ⅴ)形成稳定络合物,其最大吸收波长位于560nm处,据此提出了分光光度法测定铌钽矿浸出液中铌含量的方法。铌(Ⅴ)的质量浓度在4～240μg·L-1范围内符合比耳定律,表观摩尔吸光率为1.44×106L·mol-1.cm-1。方法用于铌钽矿样品中痕量铌的测定,测定结果与国家标准方法测定值相一致。     

氯代磺酚C光度法快速测定低级铌铁中的铌

采用氯代磺酚Ｃ光度法测定低级铌铁中的铌，对如何缩短溶样时间、加快显色速度进行了探讨。     

铌酸/氧化铌在多相催化反应中的应用

介绍了铌酸，氧化铌的结构、性质及其在多相催化反应中的研究现状及应用前景。作为一种新型的催化材料，铌酸，氧化铌由于其独特的酸性和氧化还原性正受到越来越多人的关注。它可以作为催化剂的活性组分、助剂或载体使用，在烃类转化、选择性氧化、水解、水合、缩合、加氢，脱氢等若干酸碱和氧化还原反应中得到广泛的应用。     

铌钼杂多酸的极谱行为及其应用于铌的测定

在ｐＨ２．５的硫酸、抗坏血酸溶液中，铌与钼形成了具有电活性的铌钼蓝杂多酸，并在ｐＨ８．８的ＮＨ３－ＮＨ４Ｃｌ溶液中可在滴汞电极上于－１．１０Ｖ（ｖｓ．ＳＣＥ）产生一灵敏的还原波。导数波高与铌量在０．００５￣０．４ｍｇ／Ｌ范围内呈线性关系。研究了极谱波性质，证明其为吸附波，电极反应属于准可逆。求得电极反应中电子转移数及质子转移数均为２。应用本法已测定了合金钢标样中的铌。     

单铌和单过氧铌杂多配合物的合成、表征及催化性能

过氧铌钨磷杂多酸盐;催化活性;单铌和单过氧铌杂多配合物的合成、表征及催化性能     

电感耦合等离子体原子发射光谱法测定铌精矿中铌、锰、钛

采用电感耦合等离子体原子发射光谱法测定铌精矿中铌、锰、钛的含量。选择铌、锰、钛的分析谱线分别为309.418,257.610,334.940nm。铌、锰、钛的线性范围在1.00~10.00mg·L-1之间,方法的检出限(3s)在0.010~0.015mg·L-1之间。方法用于标准样品B-K1的分析,测定值与认定值一致。加标回收率在94.5%~103%之间,测定值的相对标准偏差(n=11)在1.4%~2.7%之间。     

铌氧化物的催化效应

在周期表中处在钒副族和第二过渡系列的铌元素,与相邻的同族元素钒和钽,以及同列相邻元素锆和钼相比,虽有相近的电负性和离子半径,但化合物的催化性能却大不相同。铌催化的工业应用及其机理,已引起广泛的兴趣     

原子吸收光谱法间接测定钢铁中铌

在研究铌对原子吸收光谱法测定镍的干扰效应基础上，建立了间接测定钢铁中铌的分析方法，该法测定铌的特征浓度为０．００１２μｇ／ｍｌ／１％，直线浓度范围为０－２．０μｇ／ｍｌ，钢铁标样分析表明该法准确度，精度度均好，本文通过Ｘ射线分析及镍原子在火焰中的分布规律研究，对铌的增感机理也进行了探讨。     

4,5-二溴苯基萤光酮-溴化十六烷基三甲基铵——荧光光度法测定微量铌

本文研究了二溴苯基萤光酮-表面活性剂-铌三元体系的荧光特性,提出了以二溴苯基萤光酮-溴化十六烷基三甲基铵荧光光度法测定铌的新方法,该方法选择性和灵敏度以及重现性均很好,在λ_(ex)=420nm,λ_(em)=470 nm处铌含量在0～6μg/25ml范围内,线性关系良好、采用适当的掩蔽剂测定钢样中的微量铌,获得了满意的结果。     

稀土对钢中碳化铌溶解和析出行为的影响

通过透射电镜，Ｘ射线衍射分析，电解相分析及热模热等手段，研究了稀土对控轧含Ｎｂ钢析出相－碳化铌的结构，溶解和析出行为的影响，实验结果表明，钢中加入稀土后，碳化铌颗粒变小且弥散分布，在９００－９５０℃碳化铌析出达最高值，随温度升高析出量急骤下降，１２００℃时碳化铌基本溶解，在奥氏体化温度下，稀上有抑制碳化铌析出的作用，随稀土量增加其作用愈显著，稀土使碳化铌在奥氏体区析出时间增长，沉淀析出速度降低。     

多环芳二酐型聚酯亚胺膜的透气性能

多环芳二酐型聚酯亚胺膜的透气性能李悦生，丁孟贤，徐纪平（浙江大学高分子科学与工程研究所，杭州，３１００２７）（中国科学院长春应用化学研究所）关键词聚醚酰亚胺，聚酯酰亚胺，膜，透气性通常的聚酰亚胺加工性能较差，在芳环二酐的苯环间引入醚键等柔性基团后，其...     

微量元素与疾病诊断治疗的研究现状及展望

对国内外微量元素与疾病的关系及其诊断治疗的研究现状及研究动向进行了综述，包括：微量元素与地方病、癌肿、心血管病、糖尿病、眼病、神经系统病等。参考文献72篇。     

Determination and study on residue and dissipation of benazolin-ethyl and quizalofop-p-ethyl in rape and soil

A QuEChERS (quick, easy, cheap, effective, rugged, and safe) method for the determination of benazolin-ethyl and quizalofop-p-ethyl in rape and soil by high-performance liquid chromatography-tandem mass spectrometry has been developed in this study. The residue and dissipation of benazolin-ethyl and quizalofop-p-ethyl in rape and soil were determined with the developed method. The half-lives of benazolin-ethyl in rape straw and soil were 3.7–5.1 days and 14.3–26.3 days, respectively. The half-lives of quizalofop-p-ethyl in rape straw and soil were 5.0-6.1 days and 0.3–9.7 days, respectively. The residue of benazolin-ethyl and quizalofop-p-ethyl in rapeseed and soil were below the detection limit (i.e., 0.5?mg?kg^?1, the maximum residue level of European Union for quizalofop-p-ethyl).     

Synthesis and Optical and Redox Properties of Symmetric and Asymmetric BODIPYs

Herein, we present the synthetic route and the photophysical, electrochemical as well as laser properties of novel red‐emitting boron‐dipyrromethenes (BODIPYs) bearing arylethyne moieties. Such functionality is added along the main axis of the chromophore leading to single‐ and double‐substituted derivatives. The relationship between the dye structure and the lasing properties is studied in detail with the help of the photophysical and electrochemical properties as well as quantum mechanical simulations. The asymmetric substitution of the parent dye induces inhomogeneities in the charge distribution, which leads to an overall loss of the fluorescence capacity, mainly in polar media. Such non‐radiative deactivation processes can be softened by decreasing the electron‐donor ability of the substituent or even avoided by symmetrical substitution. Thus, grafting of the arylethyne moieties at the longitudinal axis of the indacene core results in an effective strategy to develop red‐edge BODIPYs with highly efficient and photostable laser emission.     

Ti-V基储氢合金及其氢化物的物相结构与组分优化设计

Ti-V基储氢合金在室温、常压下即可表现出良好的储氢特性,且质量储氢容量明显高于传统AB₅型储氢合金,从而在氢气的精制和回收、运输和储存及热泵等方面有较早的应用。 此外,在混合气体分离、核反应堆中处理氢的同位素、镍氢电池及燃料电池负极材料等方面也得到了广泛的研究与关注。 基于目前Ti-V基储氢合金的研究现状,概述了该类合金的优势、限制性因素(包括成因)及改性手段。 此外,为了进一步理解Ti-V基合金储氢机理、构建合金组分与储氢特性之间的对应关系,本工作重点围绕Ti-V基储氢合金及其氢化物的结构、组分优化设计展开综述,并对其未来研究方向做出展望。     

钒与糖代谢及糖尿病

微量元素钒作为生物体内必需元素，经证实有很重要的生理学功能，与机体糖代谢有十分密切的关系，且能降低糖尿病动物模型的高血糖，极有可能被开发为治疗糖尿病的药物。     

Conformations and steric and stacking interactions of trisubstituted ureas and thioureas with alkyl and phenyl groups

The monomeric ν(N—H) vibrations of various trisubstituted ureas of the R₂UPh type and -thioureas of the R₂TUPh type have been studied. The trans—out isomerism in the former and the trans—out—cis isomerism in the latter are discussed from the point of view of steric effect. The monomeric ν(N—H) vibrations of RPhUPh and RPhTUPh are also examined. The single band appearing in the spectrum of both ureas is characteristic of the cis form; this suggests the existence of phenyl—phenyl interaction (the stacking interaction proposed by Galabov et al. [10]). Behavior of ν(N—H) vibrations at several concentrations is shown to be clearly different in the three forms (trans, out and cis). The presence of the cis form is confirmed by solvent effect experiments.     

Synthesis of Tyrosol and Hydroxytyrosol Glycofuranosides and Their Biochemical and Biological Activities in Cell-Free and Cellular Assays

Tyrosol (T) and hydroxytyrosol (HOT) and their glycosides are promising candidates for applications in functional food products or in complementary therapy. A series of phenylethanoid glycofuranosides (PEGFs) were synthesized to compare some of their biochemical and biological activities with T and HOT. The optimization of glycosylation promoted by environmentally benign basic zinc carbonate was performed to prepare HOT α-L-arabino-, β-D-apio-, and β-D-ribofuranosides. T and HOT β-D-fructofuranosides, prepared by enzymatic transfructosylation of T and HOT, were also included in the comparative study. The antioxidant capacity and DNA-protective potential of T, HOT, and PEGFs on plasmid DNA were determined using cell-free assays. The DNA-damaging potential of the studied compounds for human hepatoma HepG2 cells and their DNA-protective potential on HepG2 cells against hydrogen peroxide were evaluated using the comet assay. Experiments revealed a spectrum of different activities of the studied compounds. HOT and HOT β-D-fructofuranoside appear to be the best-performing scavengers and protectants of plasmid DNA and HepG2 cells. T and T β-D-fructofuranoside display almost zero or low scavenging/antioxidant activity and protective effects on plasmid DNA or HepG2 cells. The results imply that especially HOT β-D-fructofuranoside and β-D-apiofuranoside could be considered as prospective molecules for the subsequent design of supplements with potential in food and health protection.     

Ferrocene and ferrocenium modified clays and their styrene and EVA composites

In this work, ferrocene- and ferrocenium-containing salts were employed to modify montmorillonite. X-ray measurements show an increase in the interlayer spacing upon clay modification, which means that the larger and more organophilic cations were inserted into the gallery space of montmorillonite. Attempts to prepare nanocomposites of polystyrene and ethylene vinyl acetate copolymers lead to immiscible systems; the morphology of these systems was elucidated with TEM, XRD and cone calorimetry. The thermal stability of the composites is greater than that of the virgin polymer.