纳米ZnO的制备及其光催化性能研究

本文以羟丙基纤维素(HPC)作为分散剂,运用沉淀法制备出了粒径均匀的ZnO颗粒.通过透射电子显微镜(TEM),X射线衍射(XRD),紫外可见光吸收光谱,光致发光谱(PL)对ZnO进行了性能表征,并探讨了其形成机理及制备中的影响因素.利用纳米ZnO作为光催化剂对有机染料罗丹明B进行了光降解实验,实验结果表明,此方法制备的ZnO具有良好的光催化性能,有望在治理环境污染等领域具有良好的应用.     

氨基酸的不对称化学合成

氨基酸是具有重要生理活性的物质。用一般化学反应合成的α-氨基酸为外消旋体。使用不对称反应能有效地合成某一对映体过量的氨基酸。本文就近年来氨基酸不对称化学合成的一些新进展作一概述。     

用正电子湮没技术研究加强型交联聚乙烯热收缩制品

用正电子湮没寿命谱方法，对国内外几个主要厂家的加强型热收缩制品进行了对比测试，得到了一些有参考价值的结果． The positron lifetime technique has been used to study heat shrunk products of cross linking PE which came from different factories. Same valuabled results are obtained.     

模拟函数法测定重力加速度

模拟函数法测重力加速度是针对传统的重力加速度测定中没有考虑空气阻力影响而采用的一种新型方法。本文采用此法测定了当地的重力加速度，得到了较满意的效果。     

The effect of cellular aging on the dynamics of spiral waves

Cellular aging can result in deterioration of electrical coupling, the extension of the action potential duration, and lower excitability of the cell. Those factors are introduced into the Greenberg–Hastings cellular automaton model and the effects of the cellular aging on the dynamics of spiral waves are studied. The numerical results show that a 50% reduction of the coupling strength of aging cells has a little influence on spiral waves. If the coupling strength of aging cells equals zero, the ability for the medium to maintain spiral waves will be reduced by approximately 50% when the aging cell ratio increases from 0 to 0.5, where the reduction of cell excitability plays a major role in inducing disappearance of spiral waves. When the relevant parameters are properly chosen, the cellular aging can lead to the meandering of spiral waves,the emergence of the binary spiral waves, and even the disappearance of spiral waves via the stopping rotation or shrinkage of wave. Physical mechanisms of the above phenomena are analyzed briefly.     

Infrared Spectra and Pyrolysis of Selected Molecular Models of Coal: Insight from Density Functional Calculations

Equilibrium structures and infrared spectra of four typical molecular models of coal have been studied by density functional calculations. Combining theoretical calculations on the coal models with experimental FT-IR spectra of selected low rank perhydrous coals, a plausible molecular representation for this kind of coals was proposed, and its predicted IR spectra reasonably match the experimental observation. Calculations indicate that the cleavage of the C-C bridge bond for the coal structures considered here occurs at about 540 ℃ and the C-O ether bridge bond may break under temperature ranging from 500 to 600 ℃ for the aryl-CH2-O-CH2-aryl ether bond or from 200 to 300 ℃ for the aryl-CH2-O-aryl ether bond, showing remarkable effect of the local structural environment. The coal model containing the carboxyl group may release CO2 at about 300 ℃ through the decarboxylation with a barrier of 69 kcal/mol.     

生物模板法常温合成CdS纳米线

采用新型生物模板法常温合成CdS纳米线的新方法,并对其结构和性能进行了表征。SAED分析表明:生物模板表面包覆上了结晶良好的CdS纳米颗粒。TEM照片表明:CdS纳米线长(4±0.6)μm,直径为(400±55)nm,构成纳米线的CdS颗粒尺寸为(5.5±0.3)nm。荧光光谱分析表明:该纳米线具有优异的荧光性质,使其在生物,电子领域有潜在的应用。     

MCM-41介孔分子筛组装过渡金属配合物的电子光谱

通过γ 氨丙基修饰纳米孔材料MCM 4 1,将其与过渡金属Mn ,Cu ,Co ,Fe的N ,N 双水杨醛缩乙二胺席夫碱配合物进行化学组装。用IR和Vis UV等谱学技术对其进行了初步的表征。结果表明 ,组装产物的IR光谱 ,呈现出氨基和Schiff碱相应基团的特征吸收 ,其中氨基较游离态表现出明显的红移 ,但Schiff碱相应基团的IR吸收较组装前的配合物变化不大。     

用于细胞成像的溶酶体pH荧光探针研究进展

溶酶体是真核细胞中的酸性亚细胞器,酸性生理环境异常会导致其功能紊乱,引发一系列疾病.开发用于细胞成像的溶酶体pH荧光探针在一些疾病的诊断方面具有重要意义.本文主要从分子设计和光诱导电子转移、分子内电荷转移、荧光共振能量转移等识别机理对近几年溶酶体pH荧光探针的相关研究进行概述,同时,对其发展趋势与应用前景作了展望.