Free-standing nitrogen doped graphene/Co(OH)_2 composite films with superior catalytic activity for aprotic lithium-oxygen batteries

The recent boom in large-scale energy storage system promotes the development of lithium-oxygen batteries because of their high theo retical energy density.However,their applications are still limited by the sluggish kinetic,insoluble discharge product deposition and the undesired parasitic reaction.Herein,the free-standing nitrogen doped reduced graphene oxide/Co(OH)_2(NRGO/Co(OH)_2) composite films were prepared by a facile hydrothermal method,The NRGO/Co(OH)_2 composite films display interconnected three-dimensional conductive network,which can not only promote the diffusion of O_2 and the transport of electrolyte ions,but also provide abundant storage space for discharge products.Moreover,the introduction of nitrogen-containing functional groups results in improved conductivity and electron adsorption ability,which can facilitate electron transport and enhance the surface catalytic activity.Combining with excellent catalytic performance,the lithium-oxygen batteries with NRGO/Co(OH)_2 composite film cathodes deliver low charge overpotential and excellent cycling performance.     

R600a/R23两级自动复叠制冷系统降温特性研究

以R600 a/R23两级自动复叠制冷系统为例,研究了不同配比条件下,制冷系统中的特征点温度在降温过程中变化特性。试验表明混合制冷剂的配比是自动复叠制冷系统关键问题,通过控制关键点的温度可以判断混合制冷剂的最佳配比。     

解扰动非线性发展方程的Lie-B(a)cklund方法

A new method based on Lie-B(a)cklund symmetry method to solve the perturbed nonlinear evolution equations is presented. New approximate solutions of perturbed nonlinear evolution equations stemming from the exact solutions of unperturbed equations are obtained.This method is a generalization of Burde's Lie point symmetry technique.     

脉冲响应法测量混响时间技术的研究

本文介绍了一种根据厅堂脉冲响应特性,利用计算机数字信号处理技术,迅速,准确地测量混响时间的实现方法。     

非晶硒对X射线光电转换特性的研究

非晶硒X射线光电导具有很高的固有空间分辨率,有可能研制探测X射线成象的平板化数字器件,在探测X射线成象方面倍受注目.它对X射线的光电转换特性和灵敏度是重要的性能参数之一.我们制作了约400μm厚的非晶硒膜,在1～12.5V/μm场强范围,0.2～12mR/s照射率范围测量了X射线光电流值.实验结果显示,非晶硒具有线性的光电转换特性,其灵敏度随场强的增加而增加.计算表明,对于医疗诊断常用的轫致辐射X射线谱,用X射线在非晶硒中产生一电子-空穴对所需的能量W±约50eV(10V/μm场强)     

Fourier-transform Raman and infrared spectroscopic analysis of dipyrrinones and mesobilirubins

The Fourier-transform Raman (FT-Raman), infrared (FT-IR), and UV-visible absorption spectra of four dipyrrinones and two mesobilirubins have been investigated in the solid state and in CH2Cl2 solutions. A detailed spectral analysis, assignment and discussion of these spectra are presented. The bands at 1735-1738, 1691-1707 and 1359-1377 cm(-1) which were assigned to the stretching vibrations of the C-O-C and C-O-H and symmetric deformation of C-H bonds, respectively, can act as a marker to distinguish the compounds of this class. The striking differences between the spectra of the compounds suggest that mesobilirubin XIIIalpha is tending to adopt as ridge-tile conformation, rather than linear conformation.     

模糊—神经网络控制算法及其在离心力—振动复合环境试验系统中的应用

针对离心－振动复合环境试验系统所存在的耦合性、非线性和不确定性提出了一种模糊－神经网络控制算法,利用被控对象输入输出信息离线、在线相结合学习系统的动态特性,对时变、非线性系统进行跟踪控制,并研究了该算法在系统中的实现方法。实现表明了控制系统具有良好的跟踪能力。该算法也适用于快速变化这类系统的实时控制。     

平面SH波传递算子反演方法

讨论了弹性水平层状介质中ＳＨ波的反演问题,在平面脉动ＳＨ波激励和反射模式下利用的传递算子方法逐层反演了介质的速度,密度和厚度,反演过程转化为线性回归,并且进行了数值模拟这种逐层反演方法简化了方程的阶数和计算量。     

卵磷脂与CCl4、CHCl3的反胶束中水增溶机制的研究

采用红外光谱、核磁共振谱技术研究了ＰＣ（卵磷脂）－ＣＣｌ４、ＰＣ－ＣＨ（Ｄ）Ｃｌ３反胶束中增溶水的缔合状态以及水与ＰＣ分子中不同功能基团的作用随水量的变化。实验结果表明,随反胶束捕集水量的增加,胶束中存在３种不同的缔合水：结合水,界面束缚水,类体相水,其中结合水以配位方式与ＰＣ极性端基的胆碱基团［—Ｎ＋（ＣＨ３）３］作用,以氢键与磷酸脂基ＯＰ（ＯＲ）２Ｏ－１基团结合。另外,用吸收光谱法测定饱和增溶点并根据球型反胶束模型计算了增溶后反胶束的聚集数及水核半径     

六次甲基四胺与HnXW12O40·mH2O(X=P,Si,Ge)电荷转移盐的合成、表征及非线性光学性质研究

合成了由六次甲基四胺与Ｈ３ＰＷ１２Ｏ４０·ｎＨ２Ｏ,Ｈ４ＳｉＷ１２Ｏ４０·ｎＨ２Ｏ和Ｈ４ＧｅＷ１２Ｏ４０·ｎＨ２Ｏ 形成的具有非线性光学性质的电荷转移盐,并由元素分析,红外光谱,电子光谱进行了表征。结果表明固体中阴阳离子之间存在强的相互作用;非线性光学性质研究表明,三种电荷转移盐的倍频效应分别为ＫＨ２ＰＯ４（ＫＤＰ） 的０ ．１７ ,０ ．２５ 和０ ．０６ 倍;三阶非线性系数分别为６．２ ×１０－ １３ｅｓｕ,８ ．１ ×１０ － １３ｅｓｕ和４ ．３ ×１０ － １３ｅｓｕ。