Width design for gobs and isolated coal pillars based on overall burst-instability prevention in coal mines

An investigation was conducted on the overall burst-instability of isolated coal pillars by means of the possibility index diagnosis method(PIDM). First, the abutment pressure calculation model of the gob in side direction was established to derive the abutment pressure distribution curve of the isolated coal pillar. Second, the overall burst-instability ratio of the isolated coal pillars was defined. Finally, the PIDM was utilized to judge the possibility of overall burst-instability and recoverability of isolated coal pillars.The results show that an overall burst-instability may occur due to a large gob width or a small pillar width. If the width of the isolated coal pillar is not large enough, the shallow coal seam will be damaged at first, and then the high abutment pressure will be transferred to the deep coal seam, which may cause an overall burst-instability accident. This approach can be adopted to design widths of gobs and isolated coal pillars and to evaluate whether an existing isolated coal pillar is recoverable in skip-mining mines.     

三坐标测量机在自动化生产单元中的应用

本文主要研究了面向自动化生产单元在线测量技术,总控制系统与上下料机器人、测量机、数控机床和零点定位基座进行通信连接,基于零点定位系统实现测量基准与加工基准的统一,在总控制系统中,通过产品图号对零点定位托盘夹具、被加工零件的NC程序和三坐标测量CMM程序进行关联,建立一对一的对应关系;零件加工完成后,通过测量子坐标系进行零件自动测量,实现测量基准和设计基准的统一,从而实现了三坐标测量机在自动化生产单元中的典型应用,降低加工成本,提高生产效率,保证产品质量.     

某型飞机加油口盖逆向造型及加工质量的控制

通过专业三维扫描仪对某型机加油口盖零件采取数据点,在三维CAD软件CATIA中建立数学模型,再导入UG软件中进行刀路轨迹的设计,实现数控编程与加工,然后再在Vericut软件中进行机床仿真验证,完美的实现了无数字模型的复杂曲面类零件的数控加工,促进了专业厂原依靠仿形加工类工件的加工效率和产品质量的稳定。同时,为系统件厂逆向工程技术打下了基础,也为今后生产类似零件提供了可供参考的实践经验。     

Synthesis of titanium dioxide with oxygen vacancy and its visible-light sensitive photocatalytic activity

A novel active carbon reducing process was developed for the synthesis of titanium dioxide with oxygen vacancy. In this process a nanocomposite of hydrolyzed titanium(IV) tetra-isopropoxide and the active carbon was annealed in air. The formation reaction, visible-light absorption, and visible-light sensitive photocatalytic activity of the titanium dioxide with oxygen vacancy samples were investigated using XRD, TG-DTA analyses, FE-SEM, EDS, and measurements of electric conductivity, BET specific surface area and photocatalytic activity. The nonstoichiometric titanium dioxide with oxygen vacancy sample has a rutile structure and its chemical formula can be written as Ti(IV)_1−xTi(III)_xO_(2−x/2)□_x/2, where □ is oxygen vacancy. The oxygen vacancy was introduced into the rutile structure by reducing reaction of the active carbon in a phase transformation process from anatase to rutile. The samples showed visible-light absorption with an absorption edge around 570 nm and high surface visible-light sensitive photocatalytic activity.     

Alleviation effects of Ce~(3 ) on inhibition of photochemical activity caused by linolenic acid in spinach chloroplast

Linolenic acid has great effects on the structure and function of chloroplast. The function of Ce3 on the improvement of chloro-plast photoreduction activity and oxygen evolution damaged by linolenic acid in spinach by in vitro investigation was studied. Results showed that adding Ce3 to the linolenic acid treated chloroplast could greatly decrease the reduction linolenic acid exerted on the whole chain electron transport rate and the photoreduction activity of photosystem II (PSII) and photosystem I (PSI) as well as the oxygen evolution rate of chloroplast. It indicated that Ce3 had the ability to relieve the inhibition of the photochemical reaction of chloroplast caused by lino-lenic acid to some extent.     

用户宏程序的开发与VERICUT仿真验证

通过对凸轮几何结构的研究,建立凸轮展开数学模型,进而详细介绍了宏程序的编制过程。使用VERICUT数控仿真软件对数控宏程序的仿真、测量、以及变量跟踪,最终判断宏程序的正确性。     

中国移动数据网网管系统的建设

本结合中国移动数据网网管的现状，分析了建立数据网网管系统的必要性和建设方式，并简要介绍了网管规范的体系架构、网管测试的流程和内容、被管网元的管理特性，最后提出了数据网网管建设需要注意的几个问题，并总结了网管系统的特点。     

VERICUT仿真技术在数控加工工艺与生产管理中的应用

介绍了VERICUT仿真软件的基本构成及其功能,总结了工艺系统仿真环境构建流程,讨论了仿真技术的系统性应用以及在本企业生产管理中的作用。     

Improvement of borrowing channel assignment for patterned traffic load by online cellular probabilistic self-organizing map

This paper describes an improvement of borrowing channel assignment (BCA) for patterned traffic load by using the short-term traffic prediction ability of cellular probabilistic self-organizing map (CPSOM). The fast growing cellular mobile systems demand more efficient and faster channel allocation techniques today. In case of patterned traffic load, the traditional BCA methods are not efficient to further enhance the performance because heavy-traffic cells cannot borrow channels from their neighboring cells with light or medium traffic that may have unused nominal channels. The performance can be increased if the short-term traffic load can be predicted. The predicted results can then be used for channel re-assignment. Therefore, the unused nominal channels of the light-or-medium-traffic cells can be transferred to the heavy-traffic cells that need more nominal channels. In this paper, CPSOM is used online for traffic prediction. In this sense, the proposed CPSOM-based BCA method is able to enhance the performance for patterned traffic load compared with the traditional BCA methods. Simulation results corroborate that the proposed method enables the system to work with better performance for patterned traffic load than the traditional BCA methods.     

一种基于神经网络的高压输电线故障分类器

故障分类器是输电线路保护中的基本模块。文中以一个实际500 kV输电网络为模型,提出了基于BP前馈网络 和Kohonen自组织特征映射网络的高压输电线路故障分类方法,并进行了仿真研究。结果表明：这种方法快 速、可靠,对输入信号容错性强,尤其在高阻接地故障时具有较好的分类性能,可以用于支持高速保护装 置。