尿素作为添加剂低温制备高活性的TiO2光催化剂

以钛酸丁酯为原料,尿素作为添加剂,在酸性水溶液中室温制备了稳定透明的TiO2水溶胶。经过300℃低温焙烧2 h,得到了由锐钛矿和金红石组成的TiO2混晶。用XRD、FT-IR对催化剂进行了表征。以甲基橙为降解对象研究了TiO2的光催化活性,实验结果显示所制备的TiO2具有比Degussa P25更高的催化活性,15m in后的降解率达到了78%(P25,58%)。考察了尿素添加量以及焙烧温度对TiO2催化性能的影响,当尿素与钛酸丁酯物质的量之比为3∶1,300℃下焙烧2 h为较适宜的催化剂制备条件。初步探讨了尿素作为添加剂在低温制备高活性TiO2过程中的作用。     

Synthesis, Crystal Structure, Fluorescent and Thermal Properties of Sodium Tridecafluorodizirconate Na5Zr2F13 Compound

1 INTRODUCTION Considerable research effort on the heavy metal fluoride glasses like barium, zirconium fluoride and a series of rare-earth fluorozirconate compounds du- ring the last two decades was initiated by the broad optical transmission window of these glasses and thereby the potential for ultralow-loss optical fi- bers[1~10]. The fluorozirconate of alkali metals was first reported in 1938[11], and most of the sodium and potassium fluorozirconates were reported amongthe 1940s and 19…     

碳包覆LiFePO4的一步固相法制备及高温电化学性能

Carbon coated LiFePO₄ cathode material was synthesized by one-step solid-state reaction and characterized by X-ray diffraction (XRD), field-emission-scanning electron microscope (FESEM). Electrochemical performances of the material as cathode in lithium-ion battery were investigated at medium and elevated temperature (30 and 55 ℃) by galvanostatic charge-discharge and A.C. impedance tests. The results show that carbon coated LiFePO₄ powder exhibits a well-crystallized olivine structure and spherical morphology with an average particle size of about 500 nm. Galvanostatic charge-discharge tests show that the reversible discharge capacity at 1 C and 1.5 C rates was improved from 121 and 105 mAh·g^-1 at 30 ℃ to 136 and 123 mAh·g^-1 at 55℃, respectively, while the enhancement of high temperature on electrochemical performance is less obvious at a rate lower than 0.5 C. Impedance spectra analyses indicate that the cathode material has a remarkably higher lithium-ion diffusivity at 55 ℃ than that at 30 ℃, which improves the electrochemical performance at high temperature.     

凝胶渗透色谱和气相色谱-质谱法测定动物食品中27种有机氯和15种拟除虫菊酯类农药残留量

有机氯农药虽已被世界各国禁止使用,但由于其化学性质稳定和难以降解,在环境中仍然存在有机氯农药残留,并通过食物链的富集作用,造成对食物的污染.     

Application of Short-wave Near-infrared Reflectance Spectroscopy in Controlling Extract of Fructus Cnidii Using Supercritical Carbon Dioxide

Fructus cnidii （Chinese name shechuangzi） is the fruit produced by Cnidium monnieri （L.） Cusson （Umbelliferae）. It is a perennial herb that is used to treat skin-related diseases and gynecopathyell. Recent pharmacological studies have revealed crude extracts or components isolated from fructus cnidii possess antiallergic, antipruritic, antidermatophytic, antibacterial, antifungal, and antiosteoporotic activities. Osthole and imperatorin are the major compounds present in shechuangzi. They are often used as standards for the evaluation of the quality of shechuangzi products.     

Molecularly imprinted polymers with assistant recognition polymer chains for bovine serum albumin

A new protein molecularly imprinted polymer (MIP) was prepared with grafting polyvinyl alcohol as assistant recognition polymer chains (ARPCs). The ARPCs and acrylamide monomers were interpenetrated and then polymerized on the surface of macroporous acrylate adsorbent spheres. The template BSA was removed by treatment with 2.00 mol L-1 potassium chloride (KCl) solution and the adsorbed proteins were detected with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). 0.150, 0.500, and 2.00 mo...     

不同形貌Co3O4的水热-微乳液法制备及其电化学性能

以四元微乳液(水/十六烷基三甲基溴化铵/环己烷/正戊醇)为介质, 在100 ℃水热环境下成功地合成了具有蒲公英状、剑麻状以及捆绑式结构的前驱化合物, 经300 ℃焙烧可得结构保持的Co3O4. X-射线衍射(XRD)、扫描电镜(SEM)测试表明, 所得样品为立方尖晶石结构, 同时水热反应时间对材料的形貌有很大的影响. 循环伏安和恒电流充放电等电化学测试均表明, 水热反应6 h、经热处理后得到Co3O4具有较好的电化学电容行为, 单电极比电容可达340 F·g-1.     

以纤维素/AmimCl溶液制备纤维素气凝胶

利用离子液体AmimCl溶解结合超临界CO2干燥的方法制备了纤维素气凝胶材料.研究了不同初始浓度的纤维素溶液及其在不同凝固浴中制备的纤维素凝胶的流变行为,进一步考察了纤维素溶液浓度和凝固浴种类对纤维素气凝胶材料结构的影响.结果表明,随着初始纤维素溶液浓度的增大,气凝胶的孔结构逐渐致密,比表面积随之减小;凝固浴的组成对纤维素气凝胶的结构也有较大影响.采用适当的制备条件,可以制备出高比表面积的纤维素气凝胶材料.对纤维素气凝胶的热性能进行了表征,结果表明所得到的气凝胶材料具有较好的热稳定性和较高的炭残余含量.     

双功能交联分子对生物大分子DNA磷酸骨架的修饰

利用DNA分子在水溶液中解离出的阴离子通过亲核取代反应亲核进攻重氮基乙酸叔丁酯的易离去基团重氮基来完成对DNA磷酸骨架的修饰。我们用NMR(31P)与琼脂糖凝胶电泳对结果进行表征,结果表明,DNA磷酸骨架上部分磷原子的羟基被重氮基乙酸叔丁酯修饰。