部分还原氧化石墨烯的制备、 表征及对人宫颈癌HeLa细胞的体外杀伤作用

以氧化石墨烯(GO)为原料, 利用温和方法制备了3种不同还原程度的部分还原氧化石墨烯pRGO₁, pRGO₂和pRGO₃(pRGO_1—3)； 利用傅里叶变换红外光谱(FTIR)、 拉曼光谱(Raman)、 X 射线光电子能谱(XPS)、 紫外-可见光谱(UV-Vis)、 透射电子显微镜(TEM)和 EDS能谱对其结构和形貌进行了表征. 细胞实验结果表明, 无激光照射下pRGO_1—3本身的细胞毒性较低; 近红外(NIR)激光照射下pRGO_1—3通过光热和光毒性双重作用杀伤肿瘤细胞. 实验结果显示了pRGO 在肿瘤光热疗法和光动力疗法领域的应用潜力.     

Carathéodory's method for a class of second order differential equations on the half-line

The method of equivalent variational methods, originally due to Carathéodory for free problems in the calculus of variations is extended to investigate boundary value problems for a class of second order differential equations on the half-line. Some applications are presented to illustrate the potential of this method.     

Г-环的单位元与其算子环的单位元之间的关系

г—环的单位元是其算子环中的元素.本文探讨Г—的单位与其算子环的单位元之间的关系.举例表明存在Г—环(Г_N—环)M,它的左、右算子环均有单位元,而M既无左单位元,又无右单位元.那么在什么条件下,Г—环(Г_N—环)的左、右算子环具有单位元时,其本身必定具有左、右单位元呢?对Г—环和Г_N—环分别探讨了此问题,并给出了了解答此问题的充要条件.     

Assembly of ϵ-Keggin Polyoxometalate from Molecular Crystal to Zeolitic Octahedral Metal Oxide

Zeolitic octahedral metal oxides are inorganic crystalline microporous materials with adsorption and redox properties. New ϵ-Keggin nickel molybdate–based zeolitic octahedral metal oxides have been synthesized. ³¹P NMR spectroscopy shows that reduction of Mo^VI-based molybdates forms an ϵ-Keggin polyoxometalate that immediately transfers to the solid phase. Investigation of the formation process indicates that a low Ni concentration, insoluble reducing agent, and long synthesis time are the critical factors for obtaining the zeolite octahedral metal oxides rather than the ϵ-Keggin polyoxometalate molecule. The synthesized zeolitic nickel molybdate with Na⁺ is used as the adsorbent, which effectively separates C₂ hydrocarbon mixtures.     

An evanescent field driven mono-molecular layer photoswitch: coordination and release of metallated macrocycles

Photoswitching of 'on' and 'off' coordination sites in a self assembled monolayer containing the 4-(arylazo)pyridine chromophore has been achieved using the evanescent field and illustrated through coordination and photon induced release of zinc tetraphenylporphyrin.     

Fe（Ⅲ）、Al（Ⅲ）、Ni（Ⅱ）非有机溶剂液－液萃取行为的研究

本文研究了ＰＥＧ（聚乙二醇）－２０００－钍试剂－（ＮＨ＿４）＿２ＳＯ＿４体系对Ｆｅ（Ⅲ）、Ａｌ（Ⅲ）、Ｎｉ（Ⅱ）的非有机溶剂萃取行为。指出在ｐＨ为３．５－６．５（ＮａＡｃ－ＨＡｃ）的水溶液中，有（ＮＨ＿４）＿２ＳＯ＿４存在下，Ｆｅ（Ⅲ）、Ａｌ（Ⅲ）可被ＰＥＧ－２０００相几乎完全萃取，而Ｎｉ（Ⅱ）则基本上不被萃取。从而获得了Ｎｉ（Ⅱ）与Ｆｅ（Ⅲ）、Ａｌ（Ⅲ）混合离子的定量分离。     

Conley index for random dynamical systems

Conley index theory is a very powerful tool in the study of dynamical systems. In this paper, we generalize Conley index theory to discrete random dynamical systems. Our constructions are basically the random version of Franks and Richeson in [J. Franks, D. Richeson, Shift equivalence and the Conley index, Trans. Amer. Math. Soc. 352 (2000) 3305-3322] for maps, and the relations of isolated invariant sets between time-continuous random dynamical systems and corresponding time-h maps are discussed. Two examples are presented to illustrate results in this paper.     

有序介孔Sn-SBA-15负载铂催化剂上丙烷脱氢性能的提高

丙烷脱氢制丙烯能够将低级烷烃转变成烯烃,是有效扩大丙烯来源的生产工艺.铂锡催化剂用于丙烷催化脱氢的主要缺点是稳定性差、选择性低,通过稳定锡的氧化态可以大大改善催化剂的脱氢性能及稳定性.本文采用一锅水热合成法制备了一系列高比表面积具有高度有序介孔结构的Sn掺杂的Sn-SBA-15材料,并作为载体负载铂催化剂用于丙烷脱氢反应.同时利用传统浸渍法(IM)合成了Sn/SBA-15-IM材料作为对比.结合X射线衍射(XRD)、BET比表面积和孔体积测试、红外光谱(FT-IR)、X射线光电子能谱、H2程序升温脱附(H2-TPD)、热重分析(TGA)、扫描电镜和透射电镜等多种物理化学表征手段研究了Sn-SBA-15材料和催化剂的结构性质及其丙烷脱氢反应性能.XRD和BET比表面积和孔体积测试结果表明,水热合成法原位引入助剂Sn不影响载体SBA-15的有序孔道结构,同时能够保持较大的比表面积.传统浸渍法引入Sn会堵塞载体孔道,载体比表面积及孔道有序度下降.Sn掺杂进入SBA-15骨架能够增强Sn物种与载体的相互作用,有利于Sn物种在反应过程中保持氧化态,提高催化剂丙烷脱氢反应的活性及选择性.当Sn掺杂量增至2.0 wt％时,Pt,Sn组分与载体之间的相互作用减弱,催化剂中Sn0物种所占比例增多,导致催化剂丙烷脱氢性能下降.在丙烷脱氢反应过程中,一锅法引入Sn的催化剂上反应活性和稳定性明显优于浸渍法引入Sn的催化剂.其中,Pt/0.5 Sn-SBA-15催化剂表现出最优的丙烷脱氢性能,丙烷转化率为43.8％,丙烯选择性为98.5％.