原子吸收法连续测定氧化铝中微量钙钠铁锌

本文确定以硼酸－碳酸锂为混合溶剂，在铂坩埚中于１０００℃高温炉熔融氧化铝试样，用盐酸浸取，加释放剂，保护剂和消电离剂，用空气－乙炔火焰原子吸收法连续测定四种元素的氧化物含量。该法多次分析标样含量和准确值之差均小于规定的允差范围，测定样品与ＧＢ６６０９－８６法测定的数据安全吻合，已用于１００多批次进口氧化铝的测定，本法准确，可靠，而且简便，快速，有应用推广价值。     

用Judd—Ofelt理论计算Na5Tm（WO4）4晶体中Tm^3＋的光谱参数

在已获得的Ｔｍ＆＾３＋在Ｎａ５Ｔｍ（ＷＯ４）４晶体中强度参数／Ωλ（λ＝２，４，６）基础之上，根据Ｊｕｄｄ－Ｏｆｅｌ理论计算Ｔｍ＾３＋多重激发态之间的辐射跃迁几率，辐射寿命，荧光分支比及积分发射截面等光谱参数，并对晶体实现激光输出的可能性进行讨论。     

能量粒子轰击金刚石的计算机模拟

利用Tersoff势和分子动力学方法研究了初始动能为500 eV的硼粒子注入金刚石的微观行为.结果表明：硼注入后产生温度为5000 K的热峰，其寿命为0.18 ps；同时产生半径为0.45 nm局部非晶化区域，三重配位原子数占该区域原子数的7%.薄膜表层原子向内弛豫，近表层原子向外弛豫，表面层与近表层原子的间距减少了15%，表面层表现为压应力.硼原子以B<110>分裂间隙的形式存在于金刚石结构中. 关键词： 分子动力学模拟 金刚石 硼 注入     

MgO－B_2O_3－MgCl_2－H_2O体系与盐酸滴定反应的研究

ＭｇＯ－Ｂ２Ｏ３－ＨｇＣｌ２－Ｈ２Ｏ是含硼盐湖日晒浓缩盐卤的典型体系，它与盐酸反应生成硼酸，是从天然浓缩盐卤中制取硼酸的工艺基础，以量热滴定法和ｐＨ滴定法研究该反应，结果表明，析出硼酸的反应分两步进行；合成盐卤中硼酸盐可以用ＭｇＢ２ｎＯ（３ｎ＋１）（ｎ＝１，２，３）综合统计形式来表示；天然浓缩盐卤中硼酸盐可以用四硼酸镁的统计形式进行表示．     

A possible helical model for sodium glycocholate micellar aggregates

Sodium glycocholate crystallizes in the tetragonal space group14 witha =b = 27.793(4),c = 7.937(1) Å andZ = 8. Refinement based on 2290 observed reflections led to a conventionalR = 0.10. The bile salt molecules are arranged in a helix with 2₁ symmetry stabilized mainly by polar interactions. Four helices are held together by hydrogen bonds involving water molecules, giving rise to hydrophilic channels, with a small cross section, which can include water molecules. The packing of these tetramers form hydrophobic channels containing some disordered acetone and water molecules. The helices will be checked as a model for the micellar aggregates of this important conjugated bile salt, following the same strategy successfully applied to sodium deoxycholate. Supplementary Data relating to this article are deposited with the British Library as Supplementary Publication No. SUP 82107 (20 pages).     

等离子体原子荧光光谱法测定碳酸锂中钠、钾、钙、镁、铜、铁、钴、镍、锰、锌、镉

建立了用ICP-AFS同时测定碳酸锂中11种微量金属杂质元素的方法。加入甲烷可改善检出限,方法简便,样品分析结果与AAS法结果一致。     

An efficient strategy for N-alkylation of benzimidazoles/imidazoles in SDS-aqueous basic medium and N-alkylation induced ring opening of benzimidazoles

A sustainable route for the N-1 alkylation of imidazole and benzimidazole derivatives has been developed under volatile organic solvent free condition in alkaline water-SDS system. Incorporation of SDS in the reaction medium enhances the reaction rate by suppressing the solubility issue that arises for different substrates. This method provides high yield of the alkylated product in a shorter reaction time. For reactive alkyl halides reaction proceeds at ambient temperature whereas in the cases of less reactive alkyl halides require 55–60?°C to complete alkylation process. N-alkylation induced ring opening of the heterocyclic ring in benzimidazole derivatives to multifunctional aromatic compounds were noticed at 60?°C when more than two equivalents of alkyl halide was used.     

Crosslinked carboxymethyl cellulose-sodium borate hybrid binder for advanced silicon anodes in lithium-ion batteries

Hybrid gel binder with deformable network and strong adhesive capability on silicon particles can effectively accommodate the large volume change of silicon anodes upon cycling, leading to an excellent cycling stability and high Coulombic efficiency.