N1923从碱性氰化液中萃取金(Ⅰ)的研究

采用放射性同位素198Au示踪法研究了伯胺N1923和TBP从碱性氰化液中萃取金(Ⅰ),考察了酸化率、水相pH值、萃取剂浓度等对萃取率的影响,以及NaOH对载金有机相的反萃作用。结果表明,TBP含量大于20％,酸化的N1923与KAu(CN)2摩尔比值在11时,金能够完全被萃取。载金有机相可采用0.1mol·L-1的NaOH溶液定量反萃。机理研究表明,伯胺和TBP萃取Au(CN)2-,符合BC类协同萃取机理。当金浓度大于10g·L-1时,在萃取有机相中形成纳米级的聚集体。     

Synthesis of oleanolic disaccharide derivatives

Oleanolic acid 1 exists widely in food,medicinal herbs and other plants and possesses many attractive biological activities. Recently,some oleanolic derivatives were reported to have interesting anti-tumor activities.Herein,using association principle of drug design,OA disaccharide 17 was designed and synthesized by coupling a-L-rhamnopyranosyl-(1→2)-a-L-arabinopyranosyl disaccharide moiety,which has proved to be a unique sugar sequence with strongly antitumor activity,and modified OA with a nitrile at C-17.     

胆囊组织、组织细胞膜及细胞株的FTIR研究

研究了不同病理生理状态的胆囊组织、胆囊组织细胞膜及胆囊癌细胞株的傅里叶变换红外光谱的相关性.结果显示,与正常组织比较,胆囊癌组织中脂质相关谱带(2955,2920,2870,2850和1740 cm-1)与蛋白相关谱带(1550 cm-1)强度降低;胆囊癌细胞株中脂质相关谱带与蛋白相关谱带(1550 cm-1)强度明显增加;胆囊癌组织细胞膜中脂质相关谱带强度明显增加;核酸相关吸收谱带强度变化在胆囊癌组织和胆囊癌细胞株中一致,在细胞膜中消失;I1460/I1400比值在组织、细胞株和细胞膜层面变化一致,与正常组织相比均有所减少.结果表明,与胆囊癌组织相比,胆囊癌细胞株和胆囊癌组织细胞膜的红外光谱发生了显著变化:癌组织的脂类和蛋白质的相对含量降低;癌细胞株的脂质和蛋白相对含量增加;胆囊癌组织细胞膜的脂质和蛋白相对含量升高.从组织、细胞和细胞膜3个层面阐述了癌变的分子光谱变化.I1460/I1400比值的变化在组织、细胞株和细胞膜层面变化一致,对此指标的深入研究有望获得一个良好的临床诊断指标.     

叶轮机三维反方法伴随方程推导及其应用

通常的叶轮机械三维反方法存在以下问题:与使用者的经验相关;难以考虑多叶排之间的气动匹配;不能保证取得最优解等。本文创新性地将反方法与伴随方法相结合,充分利用伴随方法的计算时间与优化变量个数无关的特性,以期克服反方法的诸多问题,建立三维自动化的优化设计体系。本文首先推导了反方法的中弧线生成方程;在此基础上得到的Euler方程的伴随方法及其边界条件,中弧线生成方程的伴随方程及其边界条件;进一步地,本文开发了相应的设计体系;最后本文以亚琛1-1/2涡轮级为算例验证了本方法的有效性。     

用于微型光谱仪的硅基多级微反射镜设计与制作研究

提出了一种基于微光机电系统技术实现的空间调制方式的微型傅里叶变换光谱仪,介绍了其分光干涉系统结构及工作原理.对其核心部件多级微反射镜的制作方法进行了研究,采用硅在KOH溶液中的各向异性腐蚀方法制作多级微反射镜,硅腐蚀后形成的(111)反射面的表面粗糙度均方根小于10nm.     

Separation of strontium from associated elements with selective specific resin and extraction chromatography

In this paper,separation of Sr from associated elements（Na,K,Ca,Mg,and Ba） was carried out using an extraction chromatographic column packed with Sr selective specific resin consisting of an octanol solution of 4,4’（5’）-bis（t-butylcyclohexo）-18-crown-6 sorbed on an inert polymeric support.Using 8.0 mol/L HNO₃ as the eluent,Ba and associated elements were eluted immediately from the column, whereas Sr was strongly retained.The adsorbed Sr could then be stripped from the column as the eluent was changed to 0.05 mol/L HNO₃.Complete Sr/Ba separation was demonstrated to be feasible in that Ba could be washed from the column leaving pure Sr by adequate rinsing with 8.0 mol/L HNO₃. Furthermore,matrix effect could be effectively eliminated and the selectivity of the method was improved.The method was applied for the determination of Sr in the high purity barium carbonate （BaCO₃） product and seawater.The recoveries of Sr in 2 samples were determined to be 93.2%and 109%, respectively.     

Coating of Al2O3 on layered Li(Mn1/3Ni1/3Co1/3)O2 using CO2 as green precipitant and their improved electrochemical performance for lithium ion batteries

Li(Mn_1/3Ni_1/3Co_1/3)O₂ cathode materials were fabricated by a hydroxide precursor method.Al₂O₃ was coated on the surface of the Li(Mn_1/3Ni_1/3CO_1/3)O₂ through a simple and effective one-step electrostatic self-assembly method.In the coating process,a NaHCO₃-H₂CO₃ buffer was formed spontaneously when CO₂ was introduced into the NaAlO₂ solution.Compared with bare Li(Mn_1/3Ni_1/3Co_1/3)O₂, the surface-modified samples exhibited better cycling performance,rate capability and rate capability retention.The Al₂O₃-coated Li(Mn_1/3Ni_1/3Co_1/3)O₂ electrodes delivered a discharge capacity of about 115 mAh·g^-1 at 2A·g^-1,but only 84 mAh·g^-1 for the bare one.The capacity retention of the Al₂O₃-coated Li(Mn_1/3Ni_1/3Co_1/3)O₂ was 90.7%after 50 cycles,about 30%higher than that of the pristine one.     

单晶NdMnO3的比热研究

研究了低温下NdMnO3单晶的比热随温度和磁场的变化(2K≤T≤200K,0T≤H≤8T).对应于Mn磁矩亚晶格的A型反铁磁(A-AF)相变,零场下的比热曲线在85K附近出现尖锐的λ形峰,随着磁场的增加,此λ峰降低展宽而且平滑变化,这与此温度附近磁化强度的变化规律一致.与磁有序相变相关的熵变约为理论值的26%,这可能是由于磁有序涨落延续在较大温区造成的.在20K以下,比热曲线出现了明显的肩膀形状的Schottky反常,其峰值随着磁场的增加而逐渐向高温移动.考虑了低温下比热的各种贡献,根据Nd3+位有效分子场(Hmf)引起的Nd3+基态双重态(GSD)劈裂对上述现象进行了解释.通过对2K≤T≤20K,0T≤H≤8T范围内比热数据的拟合,得到了样品的GSD劈裂,德拜温度和A-AF自旋波劲度系数以及它们对磁场的依赖关系.发现GdFeO3型八面体旋转引起的A-AF结构中Mn磁矩亚晶格的铁磁成分可能是Hmf的来源.     

准直系统热光学效应对静态傅里叶变换红外光谱仪光谱复原的影响研究

在以多级微反射镜为核心器件的静态傅里叶变换红外光谱仪中, 由于准直系统距离红外光源较近, 光源的热辐射会导致其局部温度升高, 从而引起材料折射率发生改变, 使得由准直系统出射的光束存在一定的发散角, 进而影响光谱仪系统复原光谱所能达到的分辨率水平. 本文研究了光谱仪系统正常工作状态下准直系统各区域的温度分布情况, 由此计算出了相应的离焦量. 通过计算准直光束发散角在光程差采样区域内的分布, 分析了由此引入的附加光程差对光谱复原的影响. 通过计算光谱结构误差随准直系统温度的变化, 得到了准直系统温度控制的合理范围. 最后, 对基于SiC光源的光谱仪进行了实验, 结果显示制冷光源复原光谱的光谱结构误差与非制冷光源的光谱结构误差相比有明显改善. 因此, 降低光源温度对减小准直系统热光学效应的影响是非常有效的. 本文的研究结果将为解决同类问题提供参考.     

Influence of terminal alkyl chain length on helical twisting property of chiral 1,2-propanediol derivatives

In this study,a novel series of chiral 1,2-propanediol derivatives with different terminal alkyl chain length were synthesized and characterized by FT-IR,~1H NMR and DSC.After doped into a nematic liquid crystal host,all the chiral dopants induced chiral nematic liquid crystals exhibiting a helix inversion with temperature variation.The results indicate that terminal alkyl chain length has a prominent influence on helical twisting property of the chiral dopants.With increasing the terminal alkyl chain le...