催化光度法测定铑的研究及其应用

在磷酸介质中,铑(Ⅲ)对溴酸钾氧化二安替比林对氨基苯基甲烷(DApAM)显色反应具有明显的催化作用,由此建立了一种铑的高灵敏分析方法,其检出限为2.0×10-2μg·L-1,铑(Ⅲ)含量在0～30μg·L-1范围内符合比耳定律,方法用于催化剂中痕量铑的测定,结果满意。     

CRYSTAL AND MOLECULAR STRUCTURE OF STEMOTININE

<正> C18H25NO5, Mr = 335.40, tetragonal, P41212, a = 15.578(4), c =14.723(3) A, V =3573(2) A3, Z = 8, D = 1.247 g cm-3, MoKα,λ= 0.71069 A, μ = 0.;85 cm-1, T = 293K, final R .= 0.100 and RW (on F2) = 0.080 for 1095 observed data [|FO| > 2σ(|FO|)]. The structure confirms the spectrbscopic assignment of a pentacyclic skeleton containing two α-methyl-γ-lactone rings, one ether and one tertiary amine.     

Calix[4] crowns with Methoxynaphthoylmethyl Pendant Groups

The novel calix [4] crowns with two pendant groups were prepared by the alkylation of calix 141 crowns with 6-methoxy-2-bromoacetylnaphthalene. ^1H NMR titration and picrate extraction experiments indicated that they exhibit higher complexing efficiency than their parent compounds and possess obvious selectivity for Na^ or K^ , respetively, and that the cation is encapsulated inside the preorganized ionophoric cavity defined by carbonyl oxygens, the crown ether and the phenoxy oxygens.From UV and fluorescent spectra it is revealed that calix [4]crown-4 3a with 6-methoxy-2-naphthoylmethyl pedant groups exhibits remarkable cation-induced photophysical effects and it could be utilized as a selective fluorescent sensor for Ca^2 .     

2-(2-喹啉偶氮)-4-甲基-1,3-苯二酚固相萃取光度法测定铜的研究

合成了新试剂2-(2-喹啉偶氮)-4-甲基-1,3-苯二酚(QAMDHB),并研究了试剂与铜的显色反应,在pH 2.2磷酸-磷酸二氢钾缓冲介质中,溴化十六烷基三甲基胺(CTMAB)存在下,QAMDHB与铜反应生成21稳定络合物,该络合物可被Waters PorapakR Sep-Park-C18固相萃取小柱萃取,用乙醇洗脱后用光度法测定,在乙醇相中λmax=550nm,ε=3.92×104L@mol-1@cm-1.铜含量在0～1.0μg@ml-1范围内符合比耳定律,方法用于环境水样中铜含量的测定,结果满意.     

Synthesis of （p—Substituted phenyl）azo Calix[4] arenes

A novel method for the preparation of chromogenic calixarenes with azo groups was reported.p-Substituted(-NO2,-CH3,-Cl)amilines were diazotized with isoamyl nitrite in EtONa/EtOH under refluxing condition.Fifteen mono-,bis-,tris-and tetrakis(p-substituted phenyl)azo calix[4]arenes (including proximal and distal isomers) were obtainged respectively by diazo-coupling in different molar ratio to calix[4]arenes(1) under pH=7.5-9.0 in non-aqueous solution at 0-5℃.^1H NMR and ^13C NMR spectra of (p-substtituted phenyl)azo calix[4]-arenes indicated that they existed in cone conformation in solution.     

三硼酸锂（LBO）晶体生长基元与形貌

本文采用称重法研究了ＬＢＯ晶体中的生长速率与溶液过饱和度之间的关系，在盯同过饱和度的条件下，同一晶体的不同界面上出现了粗糙化相变和二维成核的不同生长机制，这种现象用负离子配位体生长基元的观点得到了圆满的解释。通过对溶液结构的测定，证实了溶液中存在着Ｂ－Ｏ３三角形和Ｂ－Ｏ４四面体结构。它与晶体中的配晶位结构相同喧两种配位体形成的（Ｂ３Ｏ７）＾５－与晶体中的络阴离子环相当。环状络阴离有两个非对称分布的     

函数最值问题处理策略(高一上期)

最值问题遍及代数、三角、解析几何等各科之中,在生产实践中也有广泛的应用.以下介绍求函数最值的常用方法.一、配方法:适用于二次函数或可转化为二次函数的类型,注重变量的取值范围.例1已知函数y=(ex-a)+(e-x-a2)(a∈R,a≠0),求函数y的最小值.分析:将函数表达式按e-x+e--x配方,转化为关于为变量ex+e-x的二次函数     

生物医用高分子材料细胞膜表面功能化的策略与应用

细胞膜是细胞的外层包裹结构,保护细胞内部免受外界干扰.通过对细胞膜进行修饰,引入特定的分子或结构,可以实现对细胞命运和功能的调控,从而赋予细胞特殊的功能.近年来,利用高分子材料在细胞膜上发生自组装的策略用于功能化修饰细胞膜表面已被广泛研究.本文综述了利用高分子、多肽及DNA纳米材料对细胞膜进行修饰的策略,总结了其带来的包括受体寡聚化、细胞膜通透性改变以及调节细胞间通讯的生物效应以及细胞膜表面功能化的生物应用.     

THE INTERACTION OF Au AND THE Si/SiO2 INTERFACE DEFECT Hit(0.494)

The defects at the Si/SiO₂ interface have been studied by the deep-level transient spectroscopy (DLTS) technique in p-type MOS structures with and without gold diffusion. The experimental results show that the interaction of gold and Si/SiO₂ interface defect,H_it(0.494), results in the formation of a new interface de-fect, Au-H_it(0.445). Just like the interface defect, H_it(0.494), the new interface defect possesses a few interesting properties, for example, when the gate voltage applied across the MOS structure reduces the energy interval between Fermi-level and Si valence band of the Si surface to values smaller than the hole ionization Gibbs free energy of the defect, a sharp DLTS peak is still observable; and the hole apparent activation energy increases with the decrease of the Si surface potential barrier height. These properties can be successfully explained with the transition energy band model of the Si/SiO₂ interface.     

顺序注射化学发光联用技术测定食品中的碘

基于酸性溶液中HCHO存在下,KMnO4可氧化I-产生很强的化学发光的原理,建立了一个简单快速测定微量碘的顺序注射化学发光分析方法。I-在3.0×10-8~8.0×10-6mol/L范围内与发光强度呈良好线性关系。对2.0×10-6mol/L I-11次重复测定的相对标准偏差(RSD)为2.6%,方法的检出限(3σ)1.3×10-8mol/L,测定了4种食品中的碘量,回收率为92.8%~107.7%。分析频率为70 h。