{[Gd(DMF)_3(DMSO)(H_2O)_3](μ-CN)[Fe(CN)_5]}·2H_2O的合成,结构表征和磁性(英文)

0IntroductionThefirstmolecule鄄basedmagnetswerereportedin1986[1].Duringthelasttwodecades,moreandmoreattentionhasbeenpaidtothesynthesisofmolecule鄄basedmagnets,especiallytoPrussianBlueanalogu鄄es[2].TheoldPrussianBlueanalogueshavebeenbroughtuptodateduetoth…     

Siloxane-Based Nanobuilding Blocks by Reaction Between Silanediol and Trifunctional Silicon Alkoxides

The preparation of nanostructured organic-inorganic materials by assembling of nanobuilding blocks allows controlling the extent of phase interaction, which in its turn governs structure-properties relationships. We present here the synthesis of siloxane-based nanobuilding blocks prepared by reacting diphenylsilanediol with vinyltriethoxysilane and triethoxysilane. The reaction products were obtained by non-hydrolytic condensation between silanediol and ethoxide groups in inert atmosphere, in the presence of pyridine, triethylamine or butyl lithium. Different synthetic conditions were examined by means of ATR-FTIR and NMR spectroscopies, showing the formation of siloxane bonds. In the case of triethoxysilane the reaction carried out in the presence of pyridine leads to Si–H bond preservation in the final product. Air stable products with improved Si–O–Si hydrolytic stability can be obtained by removal of the base after the reaction completion. The condensation products can be described as a mixture of siloxane rings involving difunctional and trifunctional silicon units.     

Lamellar Organo-Bridged Silicones

The acid-hydrolysis of an organo-bridged bisdiethoxysilylated molecular precursor bearing urea groups, (EtO)₂MeSi(CH₂)₃NHCONH(CH₂)₁₂NHCONH(CH₂)₃SiMe(OEt)₂, has been performed in pure aqueous medium. Scanning electron microscopy (SEM) analysis of the resulting insoluble solid revealed plate-like forms with a lamellar structure as determined by powder X-ray diffraction (PXRD) studies with a sharp peak at 28.5 Å. The solid state ²⁹Si MAS-NMR spectrum of this bridged siloxane hybrid is consistent with a moderately condensed material with complete preservation of the Si–C bonds throughout the hybrid network. In comparison, the classical sol–gel hydrolysis-condensation of the molecular precursor in ethanol with stoichiometric amount of water and fluoride anion as catalyst produced an amorphous featureless solid.     

Compositional Profiles in Silica-Based Sol-Gel Films Doped with Erbium and Silver, by RBS and ERDA

Photosensitive organic-titania hybrid materials have been prepared from metal alkoxides and various organic ester compounds with double bonds. The refractive index of the film increases with the decrease of the concentration of the organic ester compound, and the highest refractive index of 1.62 is obtained when 2-hydroxymethyl acrylate (HOA) is used as the organic ester and the molar ratio of HOA to Ti is 0.5. The material with the highest refractive index is exposed to femtosecond pulse using the multi-beam laser interference technique. After laser irradiation, the irradiated parts of the material are photopolymerized and periodic structures can be obtained by development of the unirradiated parts. In the case of laser irradiation of 120 J total energy for 5 min, the periodic structure obtained corresponds to 2D photonic crystal structure which is composed of two parts; the material with the highest refractive index and the air.     

复合Fe2O3纳米粒子的高分子微球的结构表征

近年来，复合有机、无机粒子的高分子微球及其特殊性质越来越引起人们的兴趣与关注［1］．获得有机、无机复合微球的方法很多，如在无机粒子存在下的乳液或无皂乳液聚会[2，3]，通过可聚合的表面活性剂在粒子表面形成胶囊化层[4]以及共沉淀法等[5]．这些无机粒子包括氧化钛、氧化铁、氧化铝及氧化硅等．Haga等[6]增发现包覆在聚合物粒子中的CdS与其本体的光电性质不同；单分散的聚合物微球可以在基片上被组装成二维乃至三维有序的结构[7]．这为信息存储、立体印刷等领域提供了新途径．因此，将无机粒子与聚合物复合成为功能化粒子是一项有…     

Luminescence Properties of Tb-Doped Yttrium Disilicate Prepared by the Sol–Gel Method

A sol–gel method for the synthesis of nanosized powders of yttrium disilicate doped with Tb^{3 +} is presented. The influence of grain size and annealing temperature on the structure and luminescence properties of the materials obtained has been investigated. The preparation of glass-ceramic composite has been also described. The effect of incorporating the nanocrystals into sol–gel silica glasses on their physicochemical properties has been shown and discussed. A lack of influence of the annealing above 1300°C on the lifetimes measured for the nanocrystals embedded in the glass, as compared to the Y₂Si₂O₇:Tb^{3 +} powders, has been observed.     

三维有序大孔杂化材料SiW11O39^8——SiO2和γ—SiW10O36^8——SiO2的制备与表征

通过溶胶 -凝胶和聚苯乙烯模板等方法制备了含缺位 Keggin阴离子 Si W1 1 O8- 3 9和 γ-Si W1 0 O8- 3 6的三维有序大孔杂化氧化硅复合材料 ,并通过紫外漫反射光谱 ( UV/ DRS)、傅里叶变换红外光谱 ( FTIR)、固体核磁共振波谱 ( MAS NMR)等手段对其结构进行了表征 .结果表明 ,杂化材料中的 Keggin阴离子仍保留其基本骨架结构 ,但其与氧化硅基体之间存在化学作用 .杂化材料的孔道结构用扫描和透射电子显微镜 ( SEM和TEM)进行表征 ,其平均孔径为 ( 335± 5 0 ) nm.对杂化材料孔壁的微孔性通过氮气吸附进行了测定 .此类材料对水溶液中羟基丁二酸的降解反应具有活性 ,光催化过程中未发现 Keggin阴离子自载体中脱落的现象 .     

化学复合镀Ni-P-PTFE镀层的组成分析

近年来化学复合镀技术在工业中应用日益广泛 ,本文运用ＳＥＭ、ＡＥＳ和ＸＰＳ等手段对用化学复合镀制得的Ｎｉ Ｐ ＰＴＦＥ镀层的结构和组分进行了分析 ,并就其耐腐蚀性能与前期得到的Ｎｉ Ｓｎ Ｐ[1 ] 、Ｃｕ Ｓｎ Ｐ[2 ] 、Ｎｉ Ｐ ＣｅＯ2 [3] 、Ｎｉ Ｐ ＳｉＯ2 [4] 镀层进行了比较 ,结果表明 :含量一定的ＰＴＦＥ(聚四氟乙烯 )的共存增强镀层的耐腐蚀性及镀层表面的润滑性。1　实验部分1 1　仪器日产Ｄ/ＭＡＸⅢＡ型Ｘ 射线衍射仪 ,铜靶 ,管压 2 5ｋＶ ,电流 1 0ｍＡ。国产ＪＪＣ 1型润滑湿角测量仪。美国ＰＥＲＫＩＮ ＥＬＭＥＲＰ…     

锌基复合脱硫剂脱硫性能的研究

采用共沉淀法和机械混合法制备了Zn-Cu-Mn复合氧化物和ZCM(Z=ZnO、C=CuO、M=MnO2)复合氧化物，并对两种氧化物的脱硫能力进行了分析，同时也将这二种氧化物与单一的ZnO、MnO2和CuO的脱硫能力进行比较。利用XRD和FPD(火焰光度计)分别对复合氧化物的物质组成、结构和脱硫性能进行了分析。实验证明，Zn-Cu-Mn在250℃～350℃具有良好的脱硫能力，且300℃的脱硫能力最佳；空速为7799h-1时穿透硫容较高。煅烧温度为400℃时，Zn-Cu-Mn的脱硫能力高于ZnO。煅烧温度升高，Zn-Cu-Mn复合氧化物的比表面积和脱硫能力下降，且生成了具有尖晶石结构的CuMn2O4。与Zn-Cu-Mn复合氧化物和ZnO相比，ZCM复合氧化物的脱硫能力较低。煅烧温度为550℃时，ZCM体系中的MnO2分解为Mn2O3，当温度升至750℃时Mn2O3相消失，生成了具有尖晶石结构的CuMn2O4。     

Optimization of the process variables for the synthesis of cardanol-based novolac-type phenolic resin using response surface methodology

Models capable of predicting the maximum extent of conversion (p) of cardanol-based novolac-type phenolic resin, have been developed using response surface methodology to determine the optimum reaction conditions. Three-dimensional response surface and their contour plot were drawn. The maximum extent of conversion (98.93%) was predicted when the cardanol was condensed with formaldehyde (molar ratio 1:0.652) at 119.84 °C for a time period of 3 h with the catalyst (e.g., citric acid) concentration of 1.988% of total volume of cardanol and formaldehyde. The pH of the reaction mixture was maintained at 3.0. These predicted values for optimum process conditions were in good agreement with experimental data.