微粉微晶玻璃的致密烧结与析晶

采用R2O-CaO-MgO-Al2O3-SiO2系统,制备微粉微晶玻璃.研究合理的烧结、析晶温度制度,以及升温速率、粉体粒度对玻璃析晶、显微结构的影响,探讨提高微晶玻璃的晶体质量分数和致密度、优化微晶玻璃显微结构的途径.结果表明,采用微粉制备辉石族矿物为主晶相微晶玻璃时,粉体的巨大表面积使微晶化进程变得更加容易,晶化处...     

2维双螺旋层配合物的构筑及表征

在水热条件下合成一种新型2维(2D)聚合物[Ni2(pda)2(bpp)2(H2O)3](1)(1,4-pda=对苯二乙酸、bpp=1,3-二(4-吡啶基)丙烷).采用红外光谱、差热-热重、CHN元素分析及单晶X-射线衍射等手段对晶体结构进行了表征.配合物1属3斜晶系,空间群为P-1;晶体学参数:a=9.925(4)nm,b=12.863(6)nm,c=18.710(8)nm;α=101.813(9)°,β=99.133(9)°,γ=90.240(9)°.其基本结构单元由2个Ni(II)原子、3个对苯二乙酸根、4个1,3-二(4-吡啶基)丙烷和3个配位水分子组成.对苯二乙酸根与Ni(Ⅱ)原子交替连接形成1维右手螺旋链,相邻同手性螺旋链通过TG构型的1,3-二(4-吡啶基)丙烷连接形成2维右手螺旋层A.同样,对苯二乙酸根、Ni(Ⅱ)原子、1,3-二(4-吡啶基)丙烷形成2维左手螺旋层B.这2个相邻螺旋层A、B间通过[Ni2bpp2]闭合环的支撑形成双层2维结构.     

Dynamics of crystallization and dissolution of calcium orthophosphates at the near-molecular level

Although extensive investigations of biogenic and geological calcium phosphate crystallization/dissolution and their phase transformations have been performed,the mechanisms of crystallization and dissolution of sparingly soluble calcium phosphates in geological settings have not been completely determined at the near-molecular level.In particular,an understanding of the physical-chemical processes at the earliest nucleation stage and the subsequent crystal surface dynamics in soil solutions is lacking.This review focuses on the earliest events in homo/heterogeneous nucleation from an initial supersaturated solution phase,the subsequent growth of calcium phosphate phases,and the relevant influences of the presence of additional inorganic and organic molecules in both geological and biological settings.These studies have implications for the understanding of the complex processes of calcium phosphate transformations in soils,and provide possible physical-chemical mechanisms for the biogeochemical behavior of phosphorus at the near-molecular level.     

Preparation of high selectivity silicalite-1 membranes by two-step <Emphasis Type="Italic">in situ</Emphasis> hydrothermal synthesis

High selectivity silicalite-1 membranes were synthesized on silica tubes by in situ hydrothermal synthesis. Using a two-step synthesis, a membrane with a separation factor of 99 was prepared for separating an ethanol/water mixture at 60°C. The average (n = 4) flux and separation factor of the membranes were 0.47 kg m-2 h-1 and 89, respectively. The membranes exhibited high reproducibility, and the relative standard deviation of the average (n = 4) flux and separation factor were only 5.3% and 9.2%, respectively. These results suggest that silica is a suitable support for synthesis of high-performance silicalite-1 membranes.     

可反应性纳米SiO_2/聚己内酯杂化材料的制备和结晶性能研究

以己内酯和可反应性纳米二氧化硅为原料,在辛酸亚锡的催化作用下,原位制备了纳米SiO2/聚己内酯(PCL)杂化材料,利用红外光谱、热重分析仪和差示扫描量热仪对杂化材料的界面结构和结晶性能进行了研究.结果表明,纳米SiO2上的环氧基团在聚合过程中参与了反应,使纳米SiO2与PCL之间产生了强烈的界面作用,而且纳米SiO2的引入促进了PCL的结晶,增加了其结晶度.     

In2S3纳米晶自组装微球的无模板水热法制备及其光催化性能研究

以氧化铟、盐酸和硫脲为原料,采用简单、无模板的水热法于140℃、160℃恒温24 h分别得到In2S3纳米自组装成的不同形貌微米球。产物通过X-射线衍射仪(XRD)、扫描电子显微镜(SEM)对其结构和形貌进行表征.XRD结果表明:两种产物均为纯相立方晶相的In2S3.SEM结果表明:于140℃、恒温24 h得到In2S3纳米粒自组装微球,微球直径约3～4μm.纳米粒大小约20 nm;于160℃恒温24 h也得到In2S3纳米粒自组装形成的微球,微球大小约2.5～10μm,纳米粒大小20～200 nm.以亚甲基蓝-乙醇溶液为模型污染物,考察In2S3在紫外灯照射下的光催化性能.     

新型间硝基苯甲酸稀土配位聚合物[Nd2(C7H4O4N)7(H2O)4]n的水热合成和晶体结构

采用水热方法合成出一种新型的间硝基苯甲酸稀土配位聚合物[Nd2(C7H4O4N)7H2O]n,并通过元素分析、红外光谱、X射线单晶结构分析对该配位聚合物进行了表征.标题配位聚合物的晶体属于三斜晶系,P1空间群,晶胞参数a=0.9848(2)nn,b=1.131 4(2)nm,c=1.366 3(3)nm,α=69.22...     

晶化温度对敞开体系合成中孔分子筛Ti-MCM-41的影响

在敞开体系中合成出Ti - MCM -41,利用X射线衍射(XRD)、红外光谱(FT - IR)、紫外-可见光谱(uvVis)和孔结构测定对合成样品进行了表征,讨论了晶化温度对中孔分子筛Ti - MCM - 41晶化的影响.     

溶剂热法合成ZnO微米棒及其光催化性能

以ZnCl2和过氧化氢为反应前驱物,CTAB为表面活性剂,在碱性溶液中180℃反应12h,合成ZnO微米棒。利用X-射线粉末衍射(XRD),扫描电子显微镜(SEM),紫外可见吸收等手段对产物进行表征。通过扫描发现ZnO结构为具有六方纤锌矿结构,主要是由直径约在1μm左右粗细的单晶微米棒组成的花状ZnO微米团簇,并简单探讨了微米棒的组装过程。紫外吸附实验说明ZnO对有机染料,如甲基橙有催化作用,表明他们在光催化方面有潜在应用。     

旋流静态混合器内瞬态速度时间序列多尺度符号化分析

利用激光多普勒粒子分析仪对长径比为1.25的旋流静态混合器内瞬态流场进行测量.基于经验模态分解(EMD)方法将测得SK型静态混合器速度信号进行多尺度分解,并将分解的各阶固有模态函数IMF进行符号化,采用修正的Shannon熵(Hs)评价各尺度下的微观动力学特征.通过对静态混合器内不同尺度下瞬态速度波动信号的Hs分析,发...