秒级隔板延期装置输入输出特性的实验及数值模拟

为了将热传导技术应用到秒级延期药中控制延期时间,采用以钨系延期药作为能量输入药剂的金属隔板装置对延期时间的影响因素作了实验研究,并采用ANSYS软件进行了数值模拟验证.结果表明,在热传导过程中,第二点火药的发火是从延期装置隔板输出端的中心点开始;第二点火药的5s爆发点为189.33℃,燃点较低,利于隔板点火;装药密度越大,延期时间精度越高,当装药密度为4.0g/cm3时,相比装药密度为3.2g/cm3,其相对误差由11.2%下降到1.6%;利用Origin的数值拟合得到延期时间与隔板厚度呈二次函数关系.     

延期药和点火药燃速测试新方法

燃烧速度是延期药、点火药的重要技术指标。传统的燃烧速度测试方法只能测延期药的平均燃速，且测试精度较低。本将ＣＣＤ（光电耦合器件）技术应用于药剂燃烧速度的测试，解决了以往无法测延期药、占火药瞬时燃速的难题。以Ｔｉ－ＢａＣｒＯ４系延期药为例，用该方法对其燃烧速度进行了实际测试，得到了该延期药燃烧波面位置－时间曲线、瞬时燃速曲线以及平均燃速随压力变化的曲线。     

防静电覆铜雷管

80年代,纸壳雷管逐步被覆铜雷管所代替。由于金属在电场中会产生静电感应,因此其静电灾害要比纸质雷管大得多,给电雷管生产、运输和贮存的安全带来了严重的威胁。为此,国内外军工和矿山部门展开了一场提高覆铜管抗静电能力的角逐。我们用新发明抗静电压敏塑料成功地解决了这一难题,取得了突破性进展。 1 覆铜管静电危险 单桥丝覆铜雷管由覆铜管壳、塑料塞、引信电导线和涂有引火药头的桥丝、火药组成。当脚     

64mm防暴弹空中定点爆炸电子引信系统设计

针对现有64 mm防暴弹火药延期时间固定、发射初速度恒定,致使在使用中不能发挥最佳的作战效能的问题,采用外弹道分析计算的方法,设计一种控制64 mm防暴弹炸点的电子引信系统.结果表明:空中定点爆炸电子引信系统能够通过计算到达空间预定位置的发射角及对应时间,实现对防暴弹射程内的任意位置引爆的控制.通过实验分析,空中定点爆炸电子引信系统弥补了现有64 mm系列防暴弹存在的不足.     

引信隔爆试验内腔气体压力的工程计算

该文从真实气体状态方程出发,借鉴内弹道学中的密闭爆发器原理,在建立简化的引信雷管爆炸数学模型的基础上,得到了引信隔爆试验内腔气体压力的计算公式.针对雷管装药提出了炸药力的概念;考虑到雷管爆炸生成固体产物的影响,提出了生成气体质量系数的概念.通过分析计算,给出了引信雷管常用起爆药和猛炸药的炸药力,以及生成气体的质量系数,据此可进行引信雷管在隔爆位置爆炸时最大气体压力的工程计算.实例应用表明,该理论与实测结果符合较好,可用于解决引信隔爆强度的计算.该文研究可为引信隔爆安全性设计提供参考.     

磁流变液引信延期解除保险机构特性分析

针对准流体延期解除保险机构存在的缺陷,该文依据流体力学基本公式、磁流变液相关特性及引信环境参数,在合理假设基础上,建立了引信离心式磁流变液延期解除保险机构延期时间模型,推导出延期时间公式;利用磁导法进行了磁路设计,采用电磁场分析软件Ansoft对所设计的磁路进行数值仿真,通过仿真验证了在此磁路中磁流变液的平时安全性以及工作时泄流可靠性.通过综合分析,提出了一种使用磁流变液替代准流体的新型延期解除保险机构,该机构具有在中大口径引信中推广应用的价值.     

用小波变换识别微差爆破中的实际延迟时间

在微差爆破工程中,由于延期微差时间往往与实际延期时间有较大出入,影响了微差爆破的效果和顺利实施.基于这一现状,利用小波变换具有突出被分析信号局部特征的能力,通过分析爆破工程中所监测到的振动信号.有效地识别出微差爆破中各段雷管的起爆时刘,进而可以确定爆破中所用雷管的实际延期时间.以某地下矿山进行的微差爆破监测到的爆破振动信号进行小波分析为例,验证了此方法的有效性.图3,表3,参7.     

高强度、高精度导爆管雷管的研制

为了推广逐孔起爆技术在国内矿山大空间台阶爆破中的应用,针对高强度、高精度导爆管雷管是非电起爆系统实现"逐孔起爆"技术的关键器材,通过对导爆管、雷管延期时间及精度、延期药配比及加工工艺、延期元件制造工艺、雷管装配结构、连接块及应用软件设计等因素的系统的分析,提出了提高高强度、高精度导爆管的抗外来干扰能力,保证爆轰波的稳定性及综合性能的措施.结果表明:通过严格控制一些参数和优化结构设计,该技术可以满足生产要求,具有很好的经济效益.     

高能气体压裂用液体药点火与燃烧研究

高能气体压裂用液体药能够被点燃的点火压力、．点火热量以及能够形成其稳定燃烧的上述两个参数是液体药用于油气井高能气体压裂的两个重要参量．本文周密闭爆发器装置，用硝化棉药粉和双芳－３火药做为点火药，通过调整点火药量，得出了高能气体压裂用液体药的点火压力为５０ＭＰａ以上和点火热量及形成其稳定燃烧的点火压力和点火热量．并且得出了液体药能够被点燃的点火药为液体药的２０％．对液体药高能气体压裂现场施工设计选择点火药具有重要参考的价值．     

引信安全性设计的新发展

该文讨论了引信安全性设计方法的变化过程,详细地分析了提高错位式引信安全系统安全性的各种途径。在不可复位和可复位串、并联多道保险系统中,有序时间窗式多道保险系统的安全失效率最低。同时指出,对错位式安全系统无论进行怎样的改进,都无法消除雷管的意外发火事件,只有无起爆药雷管出现之后才解决了此问题。无起爆药雷管也推动了引信安全性设计的新发展,出现了直列式爆炸序列。文中还讨论了高能直列爆炸序列安全系统设计的方法,给出了有关结论。     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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Advances in broadband wireless communications under high-mobility scenarios

Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications （up to 574.8 km/ h test speeds or 380 km/h commercial speeds） in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.     

Perspherical Approaches for Electrons in Atoms and Charged Excitons in Quantum Wells

Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to     

Scale-based spatial data model for GIS

Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.     

英文诗歌中的喻类修辞

为了有助于提高英文爱好者的个人情操、文化素养和学习兴趣,以及专业人员对英语学习和研究进行多途径的探索,本文通过一些精选诗歌的引证和分析,着重论述了喻类修辞法在英文诗歌中的运用其及效果。     

Man Is Unable to Change the Miserable Life——Analysis of the Arrangement of Four Characters in The Glass Menagerie

Tennessee Williams is considered as one of the most important American playwrights since World War II.The Glass Menagerie is his first successful drama,which describes a tragic situation of family and means to say that Man is unable to change the miserable life,no matter whatever means he try,This essay focuses on the analysis of the arrangement of the four main characters:Laura.Amanda,Jim and Tom to reveal the theme.Laura is fragile.Amanda is brave.Jim is vital.Tom is sensible.And all of them develop and try the different means to struggle against life,but fail tragically.With the evidence,the paper comes to conclusion naturally that Man is unable to change the miserable life,and he dooms to fail.     

Characterization of root-nodulating bacteria on Retama raetam in arid Tunisian soils

The aim of this study is to investigate the diversity of Retama raetam root-nodule bacteria isolated from arid regions of Tunisia. Twelve isolates, chosen as representative for different 16S rRNA gene patterns, were characterized by 16S rRNA gene sequencing and phenotypic analysis. Isolates were assigned to Sinorhizobium, Rhizobium and Agrobacterium. Symbiotic properties of Sinorhizobium and Rhizobium isolates showed a large diversity in their capacity to infect their host plant and fix atmospheric nitrogen. Strain RK 22 identified as Rhizobium was the most effective isolate.     

WIMAX与WI-FI技术分析及联合组网

介绍了WiMAX与Wi-Fi两种无线宽带接入技术,并对两者之间的关系及相互之间的影响做了对比及分析,并对WiMAX的关键技术进行了详细说明,最后对两者的联合组网方式做了简单的探讨。     

An Affordable Accurate Evaluation of the Binding Conformations Predicted by Molecular Docking Studies in Bio-System

正Recently,docking has been widely used to predict the binding-modes of protein-inhibitors,when the crystal complexes structure was absent.Most docking algorithms are able to generate a large number of probable conformations,it,however,is difficult to effectively evaluate these docking poses and identify the most reasonable bindingmode.In the present study,on the basis of the crystallographic data of human 3-hydroxy-3-methylglutaryl coenzyme