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。     

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.     

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.     

钴/碳纤维电化学催化氧化甲苯性能研究

以纤维状活性碳吸附Co2+作为电极,在水溶液体系中,高效吸附-电化学催化氧化两步联动法矿化处理气态甲苯。实验结果显示,甲苯通过电化学反应器后能够被有效的降解。在电流密度为0.05 A·cm-2,电解电压为12 V,鼓气速率为80 L·h-1的条件下,甲苯的去除率达90%以上。甲苯降解后的主要产物为苯甲酸。     

硝基还原酶荧光探针的研究进展

硝基还原酶是一类依赖于黄素单核苷酸或黄素腺嘌呤二核苷酸的细胞质酶,广泛存在于细菌中。肿瘤细胞缺氧通常也可导致胞内硝基还原酶增加。在电子供体如还原型烟酰胺腺嘌呤二核苷酸的存在下,硝基还原酶可以将芳香族硝基化合物有效还原为相应的氨基化合物。这种还原行为不仅用于药物的激活和芳香族硝基化合物的生物降解,同时也可用来设计含硝基的荧光探针对实体瘤细胞的缺氧状况进行检测。本文简要评述近年来硝基还原酶荧光探针的研究进展,包括基于多米诺分解反应以及荧光体上硝基直接还原为氨的反应而发展的荧光探针。     

Zn-Ni-Cu铁氧体/聚邻甲氧基苯胺复合物的制备及电磁性能

用共沉淀法和溶液原位聚合法分别制备了锌镍铜铁氧体粉末(ZNCF)及其聚邻甲氧基苯胺(POMA)复合物.用粉末X-射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、振动样品磁强计(VSM)等分别表征了产物的结构、形貌、电磁性能.结果表明,ZNCF/POMA复合物的组分之间存在一定的相互作用;POMA对ZNCF粒子的包覆能起到调控样品电磁性能的作用,复合物的磁性能随POMA含量的增加而减小,而电导率则相反;与单一组分相比,POMA/ZNCF复合物表现出更优良的电磁波吸收性能,ωZNCF为20%的复合物的反射损耗峰值和有效带宽分别为-27.32 dB和8.81 GHz,峰值对应的共振频率为11.61 GHz,是颇具应用前景的电磁波吸收材料.     

2+1维Ginzburg-Landau方程的精确波解

分析研究了一个具有三次增益效应和五次耗散项的2+1维Ginzburg-Landau方程.利用同解变型法并结合一个高阶辅助方程的解,成功地取得了该方程的一些新的精确行波解.     

高质量胶体晶体薄膜的快速制备及表征

通过控制温度和湿度，用垂直沉积法（vertical deposition method）快速制备出了可精确控制样品的厚度、在较大范围呈现好的有序性的密排结构的聚苯乙烯（PS）胶体晶体 薄膜.利用透射电子显微镜直观准确地确定了样品为面心（fcc）密排结构.通过控制样品干燥速度和加温处理，胶体颗粒排列更加有序,并且克服了胶体晶体干燥后易碎和在水等溶 剂中容易再分散等缺点，为胶体晶体实际应用创造了条件. 关键词： 胶体晶体薄膜 垂直沉积法 面心密排结构 再分散     

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。     

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.