硅氧聚合度对细胞毒性的影响

本文采用家兔肺泡巨噬细胞(AM)存活率和细胞过氧化脂质(LPO)值为测定指标,研究了硅氧的聚合度对其细胞毒性的影响。结果表明:各种聚合度的硅氧都有一定的细胞毒性,聚合度愈大,细胞毒性也愈大。胶体SiO_2的粒径增大,其细胞毒性降低。十硅酸盐及粒径小于5nm的硅溶胶的细胞毒性大于α-石英。聚合度小于6的低聚硅酸及其盐、粒径18nm以上的硅溶胶以及硅胶H的毒性皆小于α-石英。本实验细胞存活率降低和过氧化脂质值升高的趋势基本一致,这表明硅氧可能主要与细胞表面膜作用,膜上磷脂等表面活性物质被氧化和变性,从而导致细胞损伤。     

Thermal decomposition kinetics of titanium hydride and Al alloy melt foaming process

Metal foams, now one of research foci, are a newclass of materials with low densities and novel physi-cal, mechanical, thermal, electrical and acoustic prop-erties[1—8]. Demands from high-tech make Al alloyfoam, which has much higher specific strength than ofpure Al foam, the new development focus[9—11]. Melt foaming process is one of the approaches tofabricate Al foam and Al alloy foam and their porestructure (pore diameter and porosity) has close rela-tionship with the thermal decompo…     

Use of factorial design for evaluation of plasma conditions and comparison of two liquid sample introduction systems for an axially viewed inductively coupled plasma optical emission spectrometer

A factorial design was applied to evaluate plasma conditions employing the Mg II 280/Mg I 285 nm intensity ratio in an axially viewed inductively coupled plasma optical emission spectrometer using different sample introduction devices: a concentric or a V-groove nebulizer and a cyclonic or a Sturman-Masters spray chamber. Effects of nebulizer gas flow-rate on Mg II/Mg I ratio were different in each introduction system. Robust conditions were obtained at low nebulizer gas flow-rate when using concentric nebulizer with a cyclonic spray chamber or a concentric nebulizer and a Sturman-Masters spray chamber. However, when using a V-groove nebulizer with a Sturman-Masters spray chamber, Mg II/Mg I ratio increased at high nebulizer gas flow-rates. Recovery experiments for a milk standard reference material diluted in water-soluble tertiary amines in both robust and non-robust conditions indicated that the robust condition was reached at higher nebulizer gas flow-rates and led to better accuracy and precision when using a V-groove nebulizer.     

Solid state synthesis of copper(I) thiotungstate cluster compounds at low heating temperatures. Crystal structures of [(n-Bu)4N]3-[WS4Cu3Cl3Br] and [Et4N]4[WS4Cu4I6]

Summary Reaction of [NH₄]₂[WS₄] with CuX (X = Cl or I) and R₄NX (R = Et or n-Bu) in the solid state gave two new bimetallic compounds with W:Cu compositions from 1:3 to 1:4. Compound (1), [(n-Bu)₄N]₃[WS₄Cu₃Cl₃Br], crystallizes in the hexagonal space group R3c with a = 17.051(5), c = 38.372(5) Å, V = 9661.8 ų, Z = 6. The cluster anion of (1) comprises a cubane-like cluster core [WS₃Cu₃Br] of C₃ symmetry with a Cl atom attached to each of the three Cu atoms and one terminal sulphido ligand attached to the W atom. Compound (2), [Et₄N]₄[WS₄Cu₄I₆], crystallizes in the monoclinic space group C2/m with a = 29.702(6), b = 12.7887(5), c = 15.327(3)Å, = 99.69(2), V = 5738.1 ų, Z = 4. In the cluster anion of (2), four edges of the WS₄ core are coordinated by four Cu atoms, giving a WS₄Cu₄ aggregate of approximate C_2V symmetry.     

聚醚聚氨酯双离子型离聚物的介电性能研究

以4,4＇-二苯基甲烷二异氰酸酯(MDI)、N-甲基二乙醇胺(MDEA)和聚四氢呋喃(PTMD)以2:1:1(mol比)合成聚醚型聚氨酯,MDEA的叔胺基与γ-丙磺内酯反应,制备了不同磺化程度的双离子型离聚物.在不同温度与频率(-150-30℃,20Hz—100KHz)下,测定了其介电性能.结果表明,随离子化程度的提高,ε＇增大,α弛豫介电损耗峰移向低温,说明相分离越趋完善;β弛豫单元的活化能(△Hβ)基本不变;α弛豫单元的活化能(△Hα)依次变小.介电测量结果与动态力学方法研究结果相吻合.     

Trifluoromethylation of carbonyl compounds with sodium trifluoroacetate

In the presence of copper(I) iodide as catalyst, a variety of carbonyl compounds, such as aldehydes, ketones and acid anhydrous, could be trifluoromethylated with sodium trifluoroacetate to give the corresponding alcohols in moderate to high yields, and a possible mechanism was proposed to explain the roles of catalyst and solvent in the reaction system.     

苯并三氮唑及其羧酸酯衍生物对铜缓蚀机理的分子动力学模拟研究

用分子动力学(MD)方法, 模拟计算了5种铜缓蚀剂[苯并三氮唑(BTA)、苯并三氮唑-5-羧酸甲酯(MBTC)、苯并三氮唑-5-羧酸丁酯(BBTC)、苯并三氮唑-5-羧酸己酯(HBTC)、苯并三氮唑-5-羧酸辛酯(OBTC)]与Cu₂O晶体的相互作用. 结果发现, 中性条件下缓蚀剂分子与Cu₂O晶体的结合能均大于酸性条件下的数值, 但两种条件下结合能的大小排序均为OBTC＞HBTC＞BBTC＞MBTC＞BTA. 对体系各种相互作用以及对关联函数g(r)的分析表明, 体系结合能主要由库仑作用提供, Cu₂O晶体中的Cu原子与缓蚀剂分子中的N原子之间形成了配位键. 在与Cu₂O(001)晶面结合过程中, BTA及其衍生物分子发生了扭曲变形, 但形变能远小于体系的非键相互作用能.     

超支化双亲水性嵌段共聚物对CaCO3结晶影响的研究

采用合成的聚乙二醇-超支化聚酯(PEG-hb-DMPA)的线性-超支化杂化二嵌段共聚物, 探讨了羧端基树状功能化的杂化嵌段共聚物对CaCO₃结晶的影响，并用FTIR、XRD、SEM等对产物进行了表征。结果表明，羧端基的双亲水性嵌段共聚物对CaCO₃结晶形貌乃至晶型均具有显著调控作用，比较高的浓度(1.67 g·L^-1, >10 min)或较低浓度作用较长时间(0.33 g·L^-1, 24 h)均得到了呈较均匀球粒形态的球霰石CaCO₃结晶。     

方酸染料在远红光区／近红外区对纳米晶二氧化钛电极的高效敏化作用

Four para-dialkylaminophenyl （PDAAP1-PDAAP4） bearing carboxyl groups were studied for application to the dye-sensitized solar cells （DSC）. It was found the short spacer CH2 between carboxyl and dialkylaminophenyl chromophore in PDAAP3 and PDAAP4 led to highly efficient monochromatic incident photon-to-current conversion efficiencies （IPCE）, however the long alkyl group C4H9 attached on aniline moieties in PDAAP2 and PDAAP4 favored improvement of open-circuit photovoltage. Thus, the solar cell sensitized by PDAAP4, having both short carboxyl groups CH2COOH and long alkyl groups C4H9, exhibited the IPCE maximum of 73% at 670 nm and overall energy conversion efficiency η of 3.06%, representing the highest IPCE and η values so far in dialkylaminophenyl-based organic dye-sensitized semiconductor solar cells. Taking advantage of the highly efficient sensitizing ability of PDAAP4 in far-red region, the data of IPCE above 630 nm of the solar cells were improved greatly by cosensitization with both N3 and PDAAP4. The influences of the TiO2 film thickness and the concentration of 4-tert-butylpyridine （TBP） in electrolyte were also investigated.     

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.