火炮寿命评估方法试验研究

为了研究磨损烧蚀火炮寿命 ,该文通过对以往火炮寿命评估方法进行分析 ,提出一种通过测量火炮内膛磨损烧蚀的新方法 ,判定火炮的弹道性能和所发射的弹数以及火炮寿命终止时的寿命发数。针对某些火炮 ,给出具体计算的经验公式 ,并通过一些试验数据对所建立的公式进行了验证 ,从而证明了采用测量火炮内膛的磨损烧蚀的方法来预测火炮寿命是可行的     

基于两相流动理论的点传火优化仿真

该文以火炮射击安全性为背景 ,利用两相流理论建立了火炮膛内过程的点传火优化仿真模型。以膛内压力波作为优化目标 ,对药包点火和中心点火管点火2种不同的点火方式进行了点传火条件的优化分析 ,并与实验结果进行了比较 ,两者有较好的一致性。这说明基于两相流动理论的优化仿真模型具有一定的可信度 ,它必将为火炮的装药及其点传火设计提供一种新的理论方法和工具     

超高射频火炮射击实验及内弹道过程仿真

该文进行了超高射频火炮膛内串联排列的3发弹丸的射击实验，建立了膛内过程的经典内弹道模型，并进行了数值模拟。计算结果和实验结果很接近，表明该模型用于模拟超高射频火炮高频连发的膛内过程是可行的。利用该模型分析了射击频率对最大膛压和初速的影响，计算结果表明：超高射频火炮的射击频率应该有一上限，就是在上一发弹出炮口并且膛内压力下降到一定压力时再击发下一发弹，才能避免各弹丸之间的相互影响，使初速散布减小。     

火炮内膛图像膛线识别及其参数计算方法研究

火炮内膛图像膛线识别及其参数计算是内膛质量评估的基础,关系到内膛疵病分析精度及其部位准确度.基于内膛图像灰度分布的特点,确定阴阳线交界点,应用数据拟合方法求得膛线缠角,采用图像处理技术将线膛火炮的内膛图像划分为阴、阳线及其过渡区域三部分,结果显示该方法具有良好的识别效果,为火炮内膛疵病图像分割与识别作好准备.     

随行装药火炮膛内流动参数特性研究

该文建立了随行装药火炮的一维两相流数学物理模型，并对某火炮的随行装药射击过程进行了数值模拟，研究了该随行装药火炮射击时膛内流动参数的变化规律。     

火炮身管寿命预测问题的研究

该文根据火炮膛内烧蚀机理，提出了预测身寿命的过程和方法，首先按该心流为两相流，边界层为湍流的模式建立了预测壁温的腔内流动数学模型，对一定火炮进行了数值模拟，其次按膛壁烧蚀量与壁温成指数关系的经验公式计算烧蚀量。最后按烧蚀量计算弹丸初速下降量，再由初速下降百分量来预估身管寿命。     

膛内燃烧与力学环境物理仿真技术研究

该文研制了发射装药膛内燃烧与力学物理环境仿真装置及其测试系统。用“探棒”测试获得了径向不同位置火药气体压力，解决了药室内同截面不同径向压力测试问题，用光纤测试获得了火焰膛内的传播过程，用弹底压力传感器获得了弹底药床被点燃前药床所处力学环境。多次试验再现并测试获得了膛内燃烧与力学环境。为发射药床膛内燃烧与力学环境和发射装药发射安全性定量研究提供了新方法。     

火炮内膛涂油弹炮接触熔化热流体模型与分析

该文就火炮内膛涂油条件下,弹丸在膛内高速运动中的弹炮接触熔化进行了分析,建立了涂油条件下的弹炮接触熔化热流体模型,进行了数值计算,计算了弹带熔化速度和厚度及其对弹丸摩擦系数的影响,结果与实验值吻合较好.计算结果表明:在弹丸滑动速度到达一定数值后,首发涂油时的摩擦系数与无油时一致.但在此之前,即弹丸运动初期的一段距离上,摩擦阻力大于后续各发,这是造成首发炮弹初速偏大,射程偏远的一个因素.该文所得结果可应用于内弹道计算,从而为认识弹丸在膛内强制滑动下的接触摩擦及其弹丸运动中的阻力机制,弄清炮膛涂油对弹丸初速的影响提供了理论依据.     

膛内多路瞬态信号硬线测试弹上系统研究

提出一种用于解决膛内异常现象探测问题的新技术 ,用PCM硬线传输技术来获取膛内多参数测试信号。研制出适于对火炮膛压单元、加速度单元和火药颗粒对弹底 (IT)作用力 3个物理参量进行测试的复合式压电传感器。并对测试系统及其传感器调理电路进行介绍。实验表明 ,该测试系统工作可靠     

某安全系统炮口失效机理分析

通过有限元方法,研究了安全系统在某大口径火炮的瞬态高过载下的动态特性. 基于膛内过载的试验测试结果,在软件中建立了安全系统有限元虚拟样机,并输入测试的弹道环境,利用有限元法进行仿真计算,得到安全系统在炮口处的强度特性;结合钟表机构的在膛内的运动,对安全系统的失效机理进行了进一步分析. 结果表明,炮口段作用在弹丸径向上的瞬态高过载是安全系统失效的主要原因.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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