Determining the number of layers in graphene films synthesized by filtered cathodic vacuum arc technique

We have synthesized graphene film by the filtered cathodic vacuum arc (FCVA) technique and determined the number of layers in graphene films by various techniques. Amorphous carbon (a-C) films of different thicknesses (1, 2, 3, 6, 10 and 18 nm) were synthesized by the FCVA technique on Si/SiO₂/Ni substrate and then annealed in vacuum at 800°C and cooled down to room temperature naturally to obtain graphene. Prepared graphene films were transferred on different substrates and characterized by the Raman spectroscopy, UV-VIS-NIR spectroscopy, high-resolution transmission electron microscopy (HRTEM), optical microscopy, atomic force microscopy (AFM) and sheet resistance to determine the number of layers present in the graphene films. Raman spectra of the prepared graphene films exhibit that there is red shift in the position of D, G and 2 D peak. The value of I_2D/I_G varied from 0.18 to 0.51, I_D/I_G varied from 0.82 to 1.02 and full width at half maximum of 2 D peak varied from 101.2 to 128.0 cm^?1, for different thicknesses of graphene films, respectively. The value of transmittance decreases from 97 to 63.7% and that of sheet resistance increases from 460 to 1400 Ω/square with the increase in the thickness of the prepared graphene film. The HRTEM and AFM study revealed that the graphene synthesis from 1 nm thick a-C film possesses a single layer structure.     

NARX-GA-Elman Method for Mach Number Prediction of Wind Tunnel Flow FieldEnglish F

Mach number is a key metric in the evaluation of wind tunnel flow field performance. This complex process of wind tunnel test mainly has the problems of nonlinearity and time lag. In order to overcome the problems and control the Mach number stability, this paper proposes a new method of Mach number prediction based on a nonlinear autoregressive exogenous-genetic algorithm-Elman (NARX-GA-Elman) model, which adopts NARX as the basic framework, determines the order of the input variables by using the false nearest neighbor (FNN), and uses the dynamic nonlinear network Elman to fit the model, and finally uses the global optimization algo-rithm GA to optimize the weight thresholds in the model to establish the Mach number prediction model with optimal performance under single working condition. By comparing with the traditional algorithm, the predic-tion accuracy of the model is improved by 61.5%, and the control accuracy is improved by 55.7%, which demonstrates that the model has very high prediction accuracy and good stability performance.     

三聚氰胺甲醛树脂包覆不同目数红磷的稳定化研究

采用原位聚合方法制备了三聚氰胺甲醛树脂包覆不同目数的红磷.对包覆红磷进行了扫描电镜、X射线光电子能谱(XPS)、吸水性、抗氧化性、pH值及热重分析测试.扫描电镜和XPS结果表明,三聚氰胺甲醛树脂在红磷表面形成了有效包覆.吸水率结果表明,三聚氰胺甲醛树脂包覆后的红磷,其吸水率随着时间增长显著降低,7d后的吸水率低于0.6...     

高层建筑结构风振计算

本文在总结结构风振试验研究的基础上,提出了高层建筑的迎风面、背风面与二侧面的动扭矩是统计独立的假定及相应的计算参数和计算方法。计算实例表明,高层建筑在风荷载作用下的扭转振动是不可忽视的。     

数字电视多媒体消息业务系统的编址寻址方案设计

研究了数字电视多媒体消息业务（TVMMS）系统的各功能单元的编址及寻址方案，讨论了数字电视多媒体消息业务系统对用户终端的编、寻址，系统对TVMMS网关／服务器的编、寻址和系统对VASP（增值业务提供商）的编、寻址，以及系统如何通过编址扩展对移动通信网和因特网的多媒体消息进行兼容．     

利用光反射探测流化床中颗粒的动力学行为

采用光导纤维探测了二维流化床中运动颗粒的反射光.光探头包含三根光纤,中间一根用于发射光,上、下各一根接收粒子反射光.颗粒速度由两路反射光强度的相关分析给出.测量给出的光脉冲信号幅值和宽度随颗粒反射面积的增加而增大.三种流化数下测得的颗粒上升速度范围为0.1—0.5 m/s.床中心和过渡区测得的颗粒上升速度随流化数的增大而增大.近壁区内颗粒主要显示下降运动以及偶然的上升,尤其是在流化数较大时颗粒下降运动更明显.     

N（O）的分布与原子核外电子分布的探讨

本文从超导电性起源于电声子机制出发,讨论了N（O）与原子核外电子层分布及电子层上的电子数的分布之间的关联问题,并用电负性均衡原理讨论了超导材料之中由于元素之间有化学键的形成,元素之间电子发生转移对N（O）的分布影响。     

Business Continuity Management: A Standards-Based Approach

ABSTRACT

Business enterprises are increasingly realizing the importance of business continuity management (BCM). Availability BS 25999 Standard has facilitated a consistent methodology that organizations can follow in designing their BCM System. This paper intends to provide a conceptual understanding of BCM right from BCM Policy to BCM maturity by describing the steps involved in the implementation of BCM Standard – BS 25999 – to ensure business continuity in the event of an outage. The key BCM tasks have been categorized into three phases of business continuity – Pre-event Preparation, Event Management, and Post-event Continuity. This paper also highlights some of the challenges experienced by the author in carrying out Risk Assessment and Business Impact Analysis. The Business Continuity Maturity Model® of Virtual Corporation is provided (with their permission) as a tool to strengthen business continuity maturity or organizations.     

BP神经网络的设计

对ＢＰ神经网络设计中的隐层节点数，初始权值，学习率等参数的选择进行研究，分别给出若干经验公式。