Preparation of Nanoelectrode Ensembles by Assembly of Nano—Silver Colloid on Gold Surface

A novel method for preparing silver nanoelectrode ensembles(SNEEs) and gold nanoelectrode ensembles (GNEEs) has been developed. Silver colloid particles were first absorbed to the gold electrode surface to form a monolayer silver colloid. N-hexadecyl nercaptan was then assembled on the electrode to form a thoil monolayer on which hydrophilic ions cannot be transfered. The SNEEs was prepared by removing thiol from silver colloid surface through applying and AC voltage with increasing frequency at 0.20V(vs.SCE). Finally,GNEEs was obtained by immersing a SNEEs into 6 mol/L HNO3 to remove the silver colloid particles. By comparison with other methods such as template method ect., this method enjoys some advantages of lower resistance, same diameter,easy preparation,controllable size and density.     

Crystal Structure and Characterization of a Large Polyoxotungstate (NH4)21{La(H2O)5[Ni(H2O)]2As4W40O140}·53H2O

The heteropolytungstate (NH4)₂₁{La(H₂O)₅[Ni(H₂O)]₂As₄W₄₀O₁₄₀}·53H₂O is obtained by the reaction of Na₂₇[NaAs₄W₄₀O₁₄₀]· 60H₂O with NiCl₂·6H₂O, La(NO₃)₃·6H₂O and NH₄Cl at pH‐4.5. The structure and chemical composition are determined by X‐ray diffraction analysis and elemental analysis. The crystal data and main structure refinement are a = 1.9551(3) nm, b = 2.4156(4) nm, c= 3.7068(6) nm, β = 91.505(3)°, V = 17.500 (5) nm³, monoclinic crystal system with space group P2₁/n, Z = 4, R₁ = 0.0573, wR₂ = 0.0717 [I >2<s?(I)], R₁, = 0.2463 and wR₂ = 0.1199 (all data). [La(H₂O)₅] {Ni(H₂O)}₂AS₄W₄₀O₁₄₀ has C₂, symmetry. IR spectra of the ligand [NaAs₄W₄₀O₁₄₀]^27‐ and its three complexes were discussed.     

细胞色素b5Glu44,Glu56的定点突变和蛋白质结构比较

用寡聚核苷酸定点突变的方法将牛肝细胞色素ｂ５基因上第４４位和５６位谷氨酸的密码子ＧＡＡ变成氨酸的密码子ＧＣＴ，获得突变体Ｅ４４Ａ，Ｅ５６Ａ和Ｅ４４／５６Ａ的基因。 它们分别克隆于ＰＵＣ１９上，转化大肠杆菌ＪＭ８３后，突变基因得到成功的表达。     

希土烯丙基化合物的研究——Ⅷ.镝、钬、铒、镱和镥的2-甲基烯丙基化合物的合成

用无水希土氯化物与2-甲基烯丙基氯化镁及四甲基乙二胺,0℃下,在四氢呋喃中反应,加乙醚后可得到五个含2-甲基烯丙基的重希土元素的化合物。经元素分析、红外光谱和质谱分析的鉴定,确定该化合物的组成为Ln(C₄H₇)₂Cl₅Mg₂(tmed)₂。     

钠硼硅酸盐玻璃分相及浸析的NMR研究

用多种ＮＭＲ方法，包括＾２９Ｓｉ、＾２３Ｎａ，＾１１Ｂ ＭａＳ及＾２９Ｓｉ ＣＰ／ＭＡＳ ＮＭＲ，研究了一定组成的ａ２Ｏ－Ｂ２Ｏ３－ＳｉＯ２三元体系玻璃在不同温度下分相处理２４小时及用酸浸析处理后的结构变化。结果表明，在低于分相上界临界温度的范围内，存在着一个温度转折点，低于这一温度时，受动力学因素影响，分相未达平衡态，温度愈低，距平衡态愈过，分相愈下完全。超过这一温度，分相可达平衡态，受热力学控     

Recyclable,non-leaching antimicrobial magnetic nanoparticles

Recyclable antimicrobial magnetic nanoparticles, Fe₃O₄@P(St-co-AcQAC), were prepared through surfactantfree seeded emulsion polymerization involving a polymerizable, hydrophobic quaternary ammonium compound (QAC). These antimicrobial magnetic nanoparticles demonstrated excellent antimicrobial activities against both Grampositive and Gram-negative bacteria, and can be reused for multiple times.     

Chiral tris(oxazoline)/Cu(II) catalyzed coupling of terminal alkynes and nitrones

Novel chiral iPr-tris(oxazoline)/Cu(ClO4)2 x 6H2O catalyzed coupling of terminal acetylenes and nitrones to afford cis-disubstituted beta-lactams is described; the choice of base proves essential to both the diastereoselectivity and the enantioselectivity.     

五硼酸钾部分高温特性的研究

研究了高温下水蒸汽及氯化钠或氯化钾对五硼酸钾的影响。借助自行设计的反应器与XRD、Raman光谱分析高温水蒸汽气氛下五硼酸钾的结构变化，证明了无论在其熔融态还是固态都会与水蒸汽发生反应，使产物中的K₂O含量升高，B₂O₃与水结合从五硼酸钾中脱离。利用DTA、XRD分析绘制了KB₅O₈-MCl（M＝K、Na）体系熔度图，属简单低共熔型，低共熔点分别为x_KCl=50%、 742 ℃，x_NaCl=20%、 689 ℃。     

氟涂料中全氟辛酸(PFOA)及其盐类物质测定的气相色谱质谱法

全氟辛酸(perfluorooctanoic acid,PFOA)是一种强酸[1],分子式为C8HF15O2,是常用的氟表面活性剂,具有很强的疏水性和疏油性,广泛用于油库、机场、军事设施等场所的消防材料中,也是氟涂料、氟塑料和有机氟织物整理剂等的生产过程中不可缺少的原料。全氟辛酸具有中等毒性的肝致癌