Cu-Zn-Sn体系富Sn区液相限的研究

近些年来,无铅低熔点填料日渐引起人们的兴趣,且将得到广泛的应用。Cu-Zn-Sn合金正是无铅低熔点填料的一种基本合金。该体系相图虽有一些报道,但他们的研究只涉及富铜区(>50Wt％)的液相限和等温截面(500℃)。我们颇感兴趣的富Sn区的液相限,尚未见文献报道,因此测定该体系富Sn区的液相限是必要的。关于Cu-Zn-Sn体系的三个相关二元体系,已有文献报道,也较成熟。对于Cu-Zn体系,富Zn区600℃以下存在两个转熔反应,其转熔点分别为Q(～88Wt％Zn,598℃),W(97.5-98.5Wt％Zn,424℃);Cu-Sn体系富Sn区有一个转熔反应,其转熔点     

Determination of trace scandium by ion-exchanger phase spectrophotometry withp-nitrochlorophosphonazo

Ion-exchanger phase Spectrophotometry withp-nitrochlorophosphonazo (CPApN) has been developed for the determination of scandium. The linear range is 1–8 g of scandium in 50 ml of solution, using 0.8 g of resin, with an apparent molar absorptivity of 2.76 × 10⁵ 1 mol^–1 cm^–1. Aluminum and rare earth elements in reasonable amounts do not interfere. The method has been applied successfully to the determination of scandium in alloys, with relative standard deviations of 2–4%.     

A new route to semirigid poly(amide-ester)s with ordered structure

Four novel semirigid poly(amide-ester)s having the same ordered amide-amide-ester-ester (-AAEE-) and the same or the different phenyl structure were synthesized from the various combination of active acylamide of benzotriazole (HBT) such as 1,1′-(isophthaloyl)bisbenzotriazole (IPBBT) and 1,1′-(terephthaloyl)bisbenzotriazole (PBBT) with diols such as N,N'-bis(2-hydroxyethyl)isophthamide (HEIPA) and N,N'-bis(2-hydroxyethyl)terephthamide (HEPTA) which prepared from the selective N-acylation of IPBBT or PBBT with aminoethanol in excellent yield at room temperature. Before the preparation of diol monomers, a model reaction of selective N-acylation was also completed from active monoacylamide of benzotriazole, 1-benzoylbenzotriazole with aminoethanol. The ordered structure of poly(amideester)s were characterized by infrared (IR) and NMR spectra. On the bases of different reactivity between selective N-acylation and O-acylation of active acylamide of benzotriazole, poly(amide-ester)s having the ordered AAEE and the same phenyl structure were also readily synthesized from the IPBBT or PBBT with aminoethanol under mild conditions by one-bath process.     

MH—Ni电池封口化成及其性能

在硼氢化钾碱性溶液中对金属氢化物（ＭＨ）电极的表面进行化学还原处理，提高了ＭＨ电极的放电容量、活化性能和电催化活性．用其为负极组装的ＡＡ型ＭＨ－Ｎｉ电池进行了封口化成，电池放电容量达到１１５０ｍＡｈ，５Ｃ下电池的放电容量达到０．２Ｃ下容量的８０％以上，电池在１Ｃ１００％ＤＯＤ（放电深度）充放电条件下，循环寿命由原来的１００次左右提高到２００次以上     

Carboxylic Acids from <Emphasis Type="Italic">Phyllanthus urinaria</Emphasis>

Five compounds, terephthalic acid mono-[2-(4-carboxy-phenoxycarbonyl)-vinyl] ester (1), (E)-3-(5′-hydroperoxy-2,2′-dihydroxy[1,1′-biphenyl]-4-yl)-2-propenoic acid (2), 3,4,5-trihydroxybenzoic acid (3), succinic acid (or butanedioic acid) (4), and 2,3,4,5,6-pentahydroxybenzoic acid (5), were isolated from Phyllanthus urinaria. The structures of these compounds were elucidated by means of spectral techniques including IR, MS, and 1D/2D NMR. 1 and 2 are new compounds.__________Published in Khimiya Prirodnykh Soedinenii, No. 1, pp. 14–17, January–February, 2005.     

Fuzzy Symmetries for Linear Molecules and their Molecular Orbitals

In this paper, the fuzzy symmetry of some prototypical linear molecules has been analyzed. The results show that some molecular orbitals (MOs) are less symmetrical but some others are more symmetrical than the molecular skeleton, which the MOs correspond to. The membership functions of space inversion for MOs are closely related to the chemical characteristics of the MOs. Sometimes, although the symmetry of a molecular skeleton is not obvious, however that of some MO is quite obvious. The membership functions of the fuzzy inversion symmetry depend on the choice of the position of the center of inversion. As compared to those of diatomic molecules and linear tri-atomic molecules, the linear polyatomic molecules in which a distinctive fuzzy symmetry of space translation may exist, and thus a significant effect on their properties can be expected.     

Synthesis and red luminescence of Pr-doped CaTiO3 nanophosphor from polymer precursor

Uniform and sphere-like nanoparticles of crystalline Pr³⁺-doped CaTiO₃ have been prepared from complex polymer precursor at 600°C, in which, metal atoms are previously dispersed by citric acid in ethylene glycol solvent. The decomposition process of the precursor, crystallization, and particle sizes of CaTiO₃ have been investigated by using thermal analysis, powder X-ray diffraction and transmission electron microscopy. Diffuse reflectance spectra, photoluminescence and decay curve indicate that a strong red emission located at the nearly NTCS “ideal red” site is deduced from the energy transfer from the band gap absorption to doping Pr³⁺ ions. The thermoluminescence curves exhibit that a potential long phosphorescent material based on Pr³⁺-doped CaTiO₃ will be explored in future.     

The first example of enantioselective isocyanosilylation of meso epoxides with TMSCN catalyzed by novel chiral organogallium and indium complexes

The desymmetrization ring opening of meso epoxides using trimethylsilyl cyanide catalyzed by organogallium and indium complexes with binaphthol monoether derivatives as chiral ligands gave beta-isocyanohydrins with moderate to excellent enantioselectivities of up to 95% ee.     

Photochemical modification and patterning of polymer surfaces by surface adsorption of photoactive block copolymers

We report a simple photolithographic approach for the creation and micropatterning of chemical functionality on polymer surfaces by use of surface-active block copolymers that contain protected photoactive functional groups. The block copolymers self-assemble at the substrate-air interface to generate a surface that is initially hydrophobic with low surface tension but that can be rendered hydrophilic and functional by photodeprotection with UV radiation. The block copolymer employed, poly(styrene-b-tert butyl acrylate), segregates preferentially to the surface of a polystyrene substrate because of the low surface tension of the polyacrylate blocks. The strong adsorption of block copolymers causes a bilayer structure to form presenting a photoactive polyacrylate layer at the surface. In the example described, the tert-butyl ester groups on the polyacrylate blocks are deprotected by exposure to UV radiation in the presence of added photoacid generators to form surface carboxylic acid groups. Surface micropatterns of carboxylic acid groups are generated by UV exposure through a contact mask. The success of surface chemical modification and pattern formation is demonstrated by X-ray photoelectron spectroscopy and contact angle measurements along with imaging by optical and fluorescence microscopy methods. The resultant chemically patterned surfaces are then used to template patterns of various biomolecules by means of selective adsorption, covalent bonding and molecular recognition mechanisms. The surface modification/patterning concept can be applied to virtually any polymeric substrate because protected functional groups have intrinsically low surface tensions, rendering properly designed block copolymers surface active in almost all polymeric substrates.     

Formation and photoluminescence of silver nanoparticles stabilized by a two-armed polymer with a crown ether core

Silver nanoparticles were synthesized by the use of a two-armed polymer with a crown ether core [poly(styrene)]-dibenzo-18-crown-6-[poly(styrene)] based on the flexibility of the polymer chains and the complex effect of crown ether with Ag(+) and Ag. The size of silver nanoparticles could be tailored by controlling the initial concentrations of the polymer and Ag(+), and the molecular weight of the polymer. The emission of silver nanoparticles was blue-shifted, and the intensity of the photoluminescence of silver nanoparticles stabilized by the polymer was significantly increased due to the complex effect between the crown ether embedded in the polymer and the silver nanoparticles.