MISCIBILITY, MICROSTRUCTURE, AND DYNAMICS OF BLENDS CONTAINING BLOCK-COPOLYMER .1. MISCIBILITY OF BLENDS OF HOMOPOLYSTYRENE WITH STYRENE-BUTADIENE BLOCK-COPOLYMERS

The miscibilities of blends of homopolystyrene/styrene-butadiene/styrene (PS/SBS) and PS/SB-4A (4-arm star block copolymer) have been studied by dynamic mechanical analysis (DMA) and C-13 CPMAS NMR techniques. The results indicate that the miscibilities o

MISCIBILITY, MICROSTRUCTURE, AND DYNAMICS OF BLENDS CONTAINING BLOCK-COPOLYMER .2. MICROSTRUCTURE OF BLENDS OF HOMOPOLYSTYRENE WITH STYRENE-BUTADIENE BLOCK-COPOLYMERS

The microstructures of styrene-butadiene triblock (SBS) and styrene-butadiene four-arm star block (SB-4A) copolymers and their blends with homopolystyrene (PS) of different molecular weights, MPS, have been investigated by means of small-angle X-ray scatt

MISCIBILITY, MICROSTRUCTURE, AND DYNAMICS OF BLENDS CONTAINING BLOCK-COPOLYMER .3. MOLECULAR-MOTION IN HOMOPOLYSTYRENE AND POLYSTYRENE 4-ARM STYRENE-BUTADIENE STAR BLOCK-COPOLYMER BLENDS

The proton spin-spin relaxation times (T-2(H)) at different temperatures (from 160 to 390 K) have been determined for polystyrene (PS) and four-arm star styrene-butadiene block copolymer (SB-4A) and its blends with PS of different molecular weights (M(PS)

SYNTHESES AND MOLECULAR-STRUCTURE OF (C8H8)LN(2,4-C7H11)THF (LN=ND, ER)

LnCl3 (Ln = Nd, Er) reacts with K2C8H8 to yield the complex (C8H8)LnCl.2THF, which reacts with K(2,4-C7H11) (2,4-C7H11 = 2,4-dimethylpentadienyl) to form (C8H8)Ln(2,4-C7H11).THF. The compound (C8H8)Nd(2,4-C7H11).THF(1) crystallizes from the mixed solvent

SYNTHESES OF (C4H7OCH2C5H4)(2)LNCL (LN=ND, GD, DY, YB) AND CRYSTAL-STRUCTURE OF (C4H7OCH2C5H4)(2)DYCL

The reaction of lanthanide trichlorides with sodium tetrahydrofurfurylcyclopentadienyl in THF afforded bis(tetrahydrofurfurylcyclopentadienyl)lanthanide chloride complexes (C4H7OCH2C5H4),LnCl (Ln = Nd, Gd, Dy, Yb). All of the complexes were characterized

SYNTHESIS AND CRYSTAL-STRUCTURE OF ((C8H8)DY[MU-OCH2(CH2)2CH=CH2](THF))2

{(C8H8)Dy[mu-OCH2(CH2)2CH=CH2](THF)}2 was prepared by the reaction of (C8H8)DyCl(THF)n with CH2=CH(CH2)2CH2ONa in THF and characterized by spectroscopic, analytical and crystallographic methods. Its crystal structure shows that the complex is a dimer with

氢化物发生-光度分析法

氢化物发生-光度分析法是在同一反应系统中,使氢化物的发生、传输、吸收显色同时进行并同步完成的一种新分析方法,具有高灵敏、高选择性,且简单实用的特点。适用于Ge、As、Sn、Sb、Se、Bi、Pb、Te等共价氢化物元素的分析。本文对这一方法的原理及其在吸收显色体系、多元素的同时或连续测定、价态形态分析、干扰的消除方法及分析应用等方面的发展进行了评述。

SYNTHESIS AND CRYSTAL-STRUCTURE OF TETRAHYDROFURFURYLCYCLOPENTADIENYL SODIUM TETRAHYDROFURANATE COMPLEX

A tetrahydrofurfurylcyclopentadienyl sodium tetrahydrofuranate complex was prepared by the reaction of tetrahydrofurfurylcyclopentadiene with metallic sodium in THF. Its crystal structure was determined by X-ray analysis. In the crystal. the tetrahydrofuranate complex C4H7OCH2C5H4Na . THF adopts a puckered chain structure with an eta5-(C4H7OCH2)C5H4 ring connected by a bridging Na(THF) unit. The oxygen in the eta5-(C4H7OCH2)C5H4 ring is coordinated to the sodium atom.

激光热透镜光度法测定痕量锑

利用He-Ne激光,观测了锑-孔雀绿络合物的激光热透镜效应。其在苯中最低检测浓度为10ng/ml Sb,测定线性浓度范围为1～120ng/ml,测定的相对标准偏差为6.5％。本方法比常规光度法的测定灵敏度高12倍,相当于吸光度3.3×10~(-4)。

共价氢化物发生-光度分析法高选择性的研究与应用——Ⅲ.SbH_3与有机胺反应机理的研究

本文以SbH_3为例,对氢化物发生-光度分析体系中有机胺溶液消除共价氢化物间干扰的作用进行了探讨。发现SbH_3被有机胺吸收后以Sb(Ⅲ)(～22％)和Sb(V)(～78％)两种形态存在,反应按并伴随与有机胺的络合进行。形态存在,反应按并伴随与有机胺的络合进行。

共价氢化物发生-光度分析法高选择性的研究与应用——Ⅰ.锗、砷、硒共价氢化物性质初探及其分别测定时其它氢化物干扰的消除

本文采用氢化物发生-银溶胶光度分析法探讨了GeH_4、AsH_3和H_2Se的性质,并利用共价氢化物气体分离柱分别建立了测定锗、砷时消除其它可生成氢化物元素干扰的简便、高效方法。测定1.0μg Ge(Ⅳ),5000μg As(Ⅴ)、Bi(Ⅱ)、Pb(Ⅰ)、1000μg Sb(Ⅱ)、Sn(Ⅰ)、500μg As(Ⅱ)和100μg Se(Ⅳ)、Sn(Ⅳ),Te(Ⅳ)不产生干扰。对砷的测定,其它共价氢化物元素的允许倍数分别为:Sb(Ⅱ)(5000)、Pb(Ⅰ)(5000)、Bi(Ⅱ)(5000)、Sn(Ⅰ)(1000)、Se(Ⅳ)(100)、Te(Ⅳ)(100)和Ge(Ⅳ)(15)。

ANALYSIS OF A NEW SUPERCONDUCTING PHASE IN THE BISRCACUO SYSTEM

By doping Sb, Ba and In to the Bi-system and with the variation of nominal atomic ratio of Cu, Sr and Ca, a new possible phase is found with T(c) almost-equal-to 105 K, but with a structure of 2212 phase. Effects of post-sintering treatment from air-quenched to O2-annealed were investigated for the approximately 105 K new phase.

SUPERCONDUCTIVITY IN BI1.5PB0.4SBXSR2CA2CU2OY SYSTEM (X=0-0.32)

The effect of doping with various amount of Sb (0.06-0.32) to (Bi,Pb):Sr:Ca:Cu = 1:1:1:1 system were studied with XRD and Tc measurements. The presence of Sb promotes the conversion of low Tc phase (2212 phase) to high Tc phase (2223 phase) and at around Sb = 0.18 the 2212 phase nearly completely disappears; but at the same time a new phase of unknown structure appears even with Sb = 0.06 showing that the incorporation of Sb into the Bi-based superconducting phase is of very low concentration. Tc measurements show that the optimum concentration of Sb-doping is around 0.10 and that unknown phase has an adverse effect to the superconducting properties; a composition disproportion at the surface of pellet was observed.

氢化物发生-分光光度法同时测定砷、锑和铋

建立了一个氢化物发生-分光光度法同时测定砷、锑、铋的新方法。在酒石酸介质中用KBH_4将 Bi(Ⅲ)、Sb(Ⅲ)、As(Ⅲ)转变成 BiH_3、SbH_3、AsH_3、再分别被乙醇、四氢呋喃、DMF混合溶液(吸收后再加入 HClO_4-DBC-CPA 溶液显色),铁-邻菲罗啉乙醇溶液和 AgNO_3、PVA、乙醇溶液分别吸收。有色溶液在640nm、510nm 和400nm 处有最大吸收。本法简便怏速,灵敏度高。检出限分别是 As 0.04μg/ml、Sb 0.09μg/ml、Bi 0.05μg/ml。用本法对铜、铜合金及沉积物中砷、锑,铋进行测定,结果令人满意。

BiPbSbSrCaCuO的超导电性

据报,在BiPbSrCaCuO中加Sb形成BiPbSbSrCaCuO体系的T_c可达130K。但其组成、结构、性质等均未见详细报道。我们合成了一系列BiPbSbSrCaCuO,发现了一个具有2212相结构、但T_c却为～110K的超导相。 试样制备包括将Bi_2O_3,PbO,Sb_2O_3,SrCO_3,CaO和CuO(AR级)混匀、碾磨、于