苯热GaP纳米微晶介质中水氧对反应过程的影响

分别以磷和GaCl~3的乙醚溶液、GaCl~3的苯溶液为原料,用苯热合成法制备了GaP纳米微晶。初步探讨了反应过程中介质中的水和氧对生成物的影响,并利用化学键的解离能数据对生成物的稳定性进行了分析。结果表明：介质中的水和氧可以在很大程度上影响反应过程,甚至改变反应进行的方向。     

反应时间对GaP纳米材料粒度的影响

以GaCl3和Na3P为原料,利用苯热合成方法,在相同的温度、不同的反应时间下制备GaP纳米粒子。由分散在苯中的GaP纳米粒子的吸收光谱和透射电子显微镜测试结果可知,反应时间延长时GaP苯溶液的光吸收谱发生明显的蓝移。本文分析了出现这一现象的原因,并从实验上进行了验证。     

苯热条件下GaP纳米晶的稳定性

用高温高压苯热合成方法制备了GaP纳米晶,用X射线衍射、光吸收谱及透射电子显微镜对所得样品进行了分析测试．结果表明,GaP纳米晶在苯热条件下是亚稳定态的,反应时间过长及反应温度过高均不利于它的生成和生长．文中还讨论了晶粒度分布与合成条件间的关系,并进行了理论上的定性分析．     

受限于不同螺旋性的纳米碳管中水的分子动力学模拟

近年来将纳米碱米碳管引入到与生命过程息息相关的离子通道膜的研究逐渐成 为热点，而其中的关键就是要了解受限于膜孔道（碳管）中水分子的行为。采用分 子动力学模拟在300 K和1.01 * 10~5 Pa下对受限于（6，6）armchair型和（10， 0）zigzag型纳米碳管中的水进行了研究，得到了水分子在碳管中的局部密度分布 等静态性质以及水分子在碳管中的传递等动态性质，并对不同势能模型的模拟结果 作了比较。结果表明选择不同的势能模型并没有改变此体系的固有性质，即水分子 不仅能够进入到憎水性的（6，6）碳管中而且能形成一条稳定的由氢键相连的纵列 （single file），而且在管中以纵列的形式进行同歇传递。此外，碳管螺旋性对 受限水的静态性质影响不大但对动态性质则有一定程度的影响，水分子在（10，0 ）zigzag型碳管中的传递能力要强于在（6，6）armchair型碳管中的能力。     

前驱体水解对纳米铂形状控制合成的影响

以聚丙烯酸钠(NaPA: M_w ≈ 2100)为保护剂，对比研究了H_2还原K_2PtCl_4 和K_2PtCl_6水溶液制备纳米铂晶粒的形状选择性，揭示了前驱体的水解对纳米铂 晶粒的形状控制合成具有显著影响。文献中通常采用的合成立方形状纳米铂的 K_2PtCl_4前驱体在水溶液中不稳定，避光静置一周会析出黑色沉淀。这种不稳定 性导致了以K_2PtCl_4为Pt前驱体的合成结果难以重复。相比而言，避光静墨的 K_2PtCl_6水溶液很稳定，以它为前驱体合成的纳米铂通常为削角八面体。 K_2PtCl_6水溶液暴露于室内光线中会出现[PtCl_6]~(-2)的光致水解。当[PtCl_6] ~(2-)的紫外特征吸收峰(260nm)由于光致水解完全消失后，以聚丙烯酸钠为保护剂 ，通过H_2还原可以有选择性地(约80%)合成由{100}晶面包裹的立方体形状的纳米 铂。     

银－金红石复合纳米微晶的光谱性能

λ>330nm光照射含有金红石型TiO2微晶颗粒的AgNO3溶液,制备出了Ag-TiO2复合超微粒子,与纯的银溶胶相比,复合粒子上银的等离子体吸收峰宽化红移,位于400～600nm。这种复合超微粒子的溶胶,表现出表面增强拉曼散射(SERS)效应。吸附-共振增强可用来解释Ag-TiO2复合粒子的SERS效应。     

聚合物对还原法合成Pt纳米粒子过程的影响

用H_2还原K_2PtCl_4溶液的方法在常温下合成了Pt纳米粒子，考察了poly(N- isopropylacrylamide)(PNIPA), poly(N-vinylacetamide)(PNVA)和poly (vinylalcohol)(PVA)等三种可溶于水的聚合物对Pt纳米粒子大小和溶胶稳定性的 影响。TEM和溶胶中加入KCl电解质溶液后溶胶稳定性测定结果表明，以PNIPA为稳 定剂可获得粒径最小的Pt粒子，且溶胶最为稳定。较高的PNIPA/Pt~(2+)摩尔比对 合成小颗粒的Pt纳米粒子有利，而聚合物的分子量对粒子影响不大。Pt晶粒在H_2 气氛下生长过程较为缓慢，停止通入还原气体H_26h后，晶粒生长才基本完成，但 溶胶在6个月后仍保持良好的稳定性。     

介质对Nafion膜孔腔中限域TiO2纳米晶体形成的影响

本文在前期工作基础上，利用高分辨电子显微镜(HRTEM)、X射线衍射仪(XRD)、扫描电镜(SEM)，能谱(EDAX)研究了在全氟磺酸离子交换膜(Nafion)模板中有机浸泡液溶剂种类、Nafion膜含水量对前驱体Ti(OBu)₄在Nafion模板中形成单分散的TiO₂纳米晶体的影响；研究了Nafion膜断面各元素含量的面分布、线分布、TiO₂的含量、粒子大小、纳米晶体微观形貌及其结构。研究结果表明，溶剂决定了Ti(OBu)₄在Nafion膜中的荷载量及相应TiO₂荷载量的大小；Nafion膜含水量不同，对膜中TiO₂荷载量影响很大，但对TiO₂晶形、晶粒大小和各元素在Nafion膜断面中的均匀分布没有显著影响。     

SnCl4对纳米二氧化钛晶相结构的低温转变控制研究

采用二种方法制备了低温下晶相结构可控制转变的纳米二氧化钛。一种方法是采用乙醇作溶剂的溶胶-凝胶法,通过控制SnCl₄的添加量,便可在450℃热处理下实现纳米TiO₂从纯锐钛矿到不同比例的复合相直至纯金红石相的转变。另一种方法是采用钛酸丁酯为原料直接低温水解,通过加入不同量的SnCl₄,制备了具有晶态结构的二氧化钛复合溶胶,在120℃下干燥处理便可实现TiO₂从锐钛矿到不同比例的复合相(金红石型、锐钛矿型和板钛矿型)直至纯金红石相的转变,制备所需晶态结构的纳米TiO₂。所有样品进行了透射电镜与XRD表征,制备的纳米TiO₂及其TiO₂-SnO₂纳米复合材料颗粒小、分布均匀、分散性好,没有检测到SnO₂晶体的X-衍射特征峰。     

酸碱处理后纳米微晶纤维素的热行为分析

Nanocrystalline cellulose (NCC) was prepared from microcrystalline cellulose (MCC) by acid hydrolysis. It was observed that the diameter of NCC particles mainly distributed over 30-50nm by transmission electron microscope (TEM) . The crystal form and degree of crystallinity were detected by X-Ray diffraction. The results showed that NCC and MCC have the same crystal form of cellulose I, and that the reactions mainly occurred in the amorphous region of MCC during the acid hydrolysis process. The thermal behavior of NCC in different pH conditions was characterized by differential scanning calorimetry (DSC) . The consequences indicate that the thermal stability of NCC distinctly decreased by contrast with the thermal stability of MCC, and that the thermal stability of NCCs in alkali conditions was higher than that of NCCs in acid conditions. The specific surface area distinctly increased with sharp decreasing of the particle size of NCC. This induced the end carbons and active groups of surface of NCC to increase sharply, therefore caused the thermal stability of NCC to distinctly abate. That NCC has very strong adsorption affinity is the cause of the obvious difference of thermal behavior of NCC in different pH. In acid conditions the surface of NCC adsorbed a great lot of H^ , which induced the cellulose chains of surface of NCC to decompose at low temperature catalyzed by H^ . When adding sodium hydroxide solution, on one hand the H^ of surface of NCC was neutralized; on the other hand, the cellulose chains of low molecular weight were dissolved in sodium hydroxide solution and the defects of surface of NCC rearranged and stable structure formed. These factors improved the thermal stability of NCC in alkali conditions.     

三氯化镓席夫碱配合物的合成与晶体结构

在无水无氧条件下,利用三氯化镓与水杨醛缩间氯苯胺反应合成了一种新的席夫碱配合物C13H10ClNO·GaCl3。利用元素分析、核磁共振、红外光谱和X射线衍射单晶结构分析对其进行了表征。单晶结构表明标题配合物晶体属于正交晶系,Pnma空间群,晶胞参数:a=17.873(3),b=7.0853(13),c=12.677(2),α=90,β=90,γ=90,V=1605.4(5)3,Z=4,F(000)=808,R1=0.0283,wR2=0.0649。该配合物中镓以四配位形式存在,形成畸变的四面体结构,配合物依靠分子间的氢键作用进一步联结成二维网状结构。     

一种双钒帽多金属氧酸盐的水热合成及其晶体结构和热稳定性

采用水热法合成了一种双钒帽多金属氧酸盐[CrⅢ(1,10-phen)2(H2O)]2[PMoⅤ6MoⅥ6O40(VⅣO)2(OH)];利用元素分析、红外光谱、单晶X射线衍射表征了其组成和分子结构,利用热重分析测定了其热稳定性.结果表明,合成的化合物由无序的双帽假Keggin型[PMoⅤ6MoⅥ6O40(VⅣO)2(OH)]6-杂多阴离子和两个[CrⅢ(1,10-phen)2(H2O)]3+配位阳离子单元组成,其热失重分两步进行,热稳定性良好.     

Thermodynamical modeling of silicon carbide synthesis in thermal plasma

The synthesis process of solid SiC in thermal plasma was investigated theoretically by computing the equilibrium composition of the gas mixtures involving silicon and carbon in the presence of argon and hydrogen at various silicon/carbon amounts and at two different total pressures in the system, in the temperature range between 1000 and 6000 K. Use is made of the fact that a thermal plasma, by definition, is a plasma in (local) thermodynamical equilibrium, which makes possible the theoretical determination of its equilibrium composition at definite temperature by employing Gibbs free energy data for the compounds present in the system. From the calculated compositions of the investigated gas systems the temperature-composition phase diagrams were obtained. Using these data the temperature zones with saturated and/or oversaturated vapour of SiC as well as of Si and C were determined and the possibility of the formation of SiC in the solid state via different reaction routes was analyzed This revised version was published online in July 2006 with corrections to the Cover Date.     

（4，4＇-bipyH）3[PW12O40]（4，4＇-bipy）·7H2O的水热合成、晶体结构与热性质

用中温水热技术合成了(4,4'-bipyH)3[PW12O40](4,4'-bipy)·7H2O,用元素分析、X射线单晶衍射、IR、UV-vis和TG-DTA 对其进行了表征.结果表明,化合物的晶体属单斜晶系,P2(1)/c空间群.标题化合物是由3个质子化的4,4'-bipy分子、一个Keggin结构的钨磷杂多阴离子[PW12O40]3-和一个4,4'-bipy分子及7个结晶水分子所组成.钨磷杂多阴离子与质子化的联吡啶及结晶水分子之间通过氢键作用,连接成无限二维层状结构,形成超分子化合物.     

制备条件对磷化钼加氢脱硫催化活性的影响

采用程序升温还原方法制得磷化钼(MoP)催化剂,在常压连续微型化反应装置中,以噻吩为模型化合物,对催化剂的加氢脱硫活性进行评价。考察了还原温度、磷钼摩尔比、不同磷源等制备条件对MoP催化活性的影响。实验结果表明,在MoP生成温度区间内,随着还原温度的升高,催化剂活性降低;磷钼摩尔比为1∶1时,噻吩转化率最高,而磷钼摩尔比为1∶2和2∶1时制备催化剂的催化活性相当;采用磷酸二氢铵、磷酸铵以及磷酸为磷源,均可制得磷化钼,而以磷酸二氢铵为磷源时制备磷化钼催化剂的活性最佳。在噻吩加氢脱硫反应条件下反应后,不同磷源制备的磷化钼整体物相均没有发生变化。     

苯甲酸钐的水热合成和热分解反应机理

用水热法合成了无水苯甲酸钐配合物,经元素分析、IR和X射线粉末衍射表征了该配合物,系层状结构,属单斜晶系。用TG、DTA、IR、色谱-质谱联用仪研究了它的热分解机理。在氮气氛下,热分解分两步进行:第一步分解生成钐的二碳酸一氧盐和有机化合物。生成的有机化合物成分比较复杂,主要成分为苯甲酸、二苯甲酮、9,10-蒽醌和1,3-二苯基异苯并呋喃等。第二步二碳酸一氧盐进一步分解生成氧化钐和二氧化碳。     

About the synthesis and thermal stability of SiO2-aerogel

Aerogels are extremely porous high-tech materials based on inorganic oxides, especially silica. The paper describes synthesis and properties of SiO₂-aerogel, and changes occurring during heating of SiO₂-aerogel in the temperature range from 20 to 1000°C. Four thermoanalytical methods were used: Thermodilatometry, Differential thermal analysis, Thermogravimetry and Derivative thermogravimetry.     

Structure and thermal behavior of metastable sillenites prepared by mechanochemical synthesis

The structure and thermal behavior of metastable solid solutions with nominal compositions Bi₂PbO₄, Bi₄HgO₇, Bi₁₂TlO_19.5, and Bi₁₂Cd_0.7O_18.7 with the sillenite structure obtained by mechanochemical treatment in a planetary mill (thermal decomposition of the metastable Bi₄CdO₇ phase with a bcc structure above 700 K) have been studied. The large Pb²⁺ atoms occupy up to ~30% positions in the sillenite structure (Hg²⁺ and Hg(1) occupy up to ~15% of (24f) positions). The (2a) sites are partially occupied by bismuth with a minor shift along the [111] axis and are transformed into the (8c) site, forming an umbrella structure with c.n. 3. The relatively small Cd²⁺and Tl³⁺ cations partially occupy the (2a) sites. During annealing, the metastable Pb-sillenites are partially stabilized with a loss of oxygen and increasing content of bismuth. Sillenite with a high content of lead retains its structure until it melts at 923 K. Cadmium sillenite reacts with CdO, passing into a rhombohedral structure at 900 K (30 K below the melting point). Mercury sillenite Bi₄HgO₇ decomposes with isolation of metallic mercury at ~600 K.Original Russian Text Copyright © 2004 by V. V. ZyryanovTranslated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 3, pp. 480–490, May–June 2004.     

固态"绝对"不对称合成

光学活性生物分子的形成是世界进化历史中一个重要过程。"绝对"不对称合成, 即在没有任何外界手性诱导试剂作用下或在圆偏振光影响下的封闭体系中的不对称合成, 为前生物时期天然手性的成因提供了解释。本文将综述通过非手性分子形成的手性晶体的固相反应进行的"绝对"不对称合成。