带大隔板爆炸成型弹丸战斗部药型罩结构研究

为研究爆炸成型弹丸(EFP)药型罩结构,基于爆轰波在有大直径隔板的EFP装药结构中的传播特性,建立了马赫波作用下罩顶微元压垮速度理论计算模型。理论计算结果表明,药型罩顶部局部加厚可以显著地降低罩顶微元压垮速度,避免EFP头部断裂;当厚度增加量过大时会导致EFP头部出现射滴和包心,对EFP飞行稳定性和侵彻威力造成负面影响。数值模拟结果表明,罩顶局部加厚不会显著降低EFP速度和长径比;当罩顶局部厚度增加量为12.5%~25.0%时,既能避免EFP头部断裂,又能避免EFP头部出现射滴和包心。对带隔板EFP战斗部进行了X光实验,实验结果验证了数值模拟结果的正确性。     

球缺型EFP战斗部结构优化设计研究

该文采用正交优化设计方法,利用数值模拟手段,对球缺型EFP战斗部优化设计进行研究.分析了战斗部结构参数对EFP成型性能的影响规律,优化得到了口径为Φ65 mm的变壁厚球缺型EFP装药结构方案.该装药形成的EFP速度约为2.5 km/s、长径比约为3.15,对应方案的EFP外形及速度的X光试验结果与仿真计算结果吻合较好.     

基于非等壁厚药型罩的准球形爆炸成型弹丸成型因素研究

采用试验验证过的数值模型,以爆炸成型弹丸速度、比动能和长径比为评价指标,系统地研究了装药长径比、药型罩内径、外径和药型罩中心厚度等对指标的影响规律,获得一种基于非等壁厚药型罩的准球形爆炸成型弹丸成型方案. 结果表明基于非等壁厚药型罩的准球形爆炸成型弹丸成型规律不同于利用挡环形成的准球形爆炸成型弹丸,以及同样利用非等壁厚药型罩形成的长杆式爆炸成型弹丸. 该爆炸成型弹丸成型方法结构简单,并可以实现较好的准球形爆炸成型弹丸外形和侵彻威力.      

翻转成型大长径比爆炸成型弹丸的数值模拟

以药型罩完全向后翻转方式生成的爆炸成型弹丸(explosively formed penetrator,EFP)通常无法完全闭合,带有较大的中空段,制约了EFP的长径比的进一步提高,而长径比是决定EFP侵彻威力的重要参数之一。对EFP的成型方式和药型罩型式之间的关系进行了分析,以进一步提高EFP的长径比为目标,设计了带有偏心药型罩和复合装药的EFP战斗部方案,以保证翻转后的药型罩完全闭合,进而生成大长径比的EFP。仿真算例表明由Φ190 mm口径EFP战斗部的药型罩转化生成的EFP,长径比为8. 13∶1,对钢靶板的侵彻深度达到1倍战斗部口径,为翻转成型方式在大威力EFP战斗部中的应用提供了技术支撑。     

药型罩壁厚对EFP成型性能影响试验

为了得到EFP成型性能与药型罩壁厚之间的关系，进行了不同药型罩壁厚的EFP侵彻钢靶板实爆试验。通过网靶测速、EFP对40mm钢靶板的破孔深度和大小试验，获得了大量EFP速度、破孔深度和大小等数据。试验结果表明：药型罩壁厚对EFP速度和侵彻能力的影响很大，在适当的壁厚条件下EFP能穿透40mm钢靶板。在试验数据分析基础上，得到了药型罩壁厚与EFP的速度和侵彻深度之间的关系和σ／Dk的合理匹配关系。     

药型罩参数对EFP成型性能影响的灰关联分析

为了分析药型罩参数对爆炸成型弹丸(EFP)形成的影响,采用数值模拟方法计算出18种不同方案下EFP成型后的性能参数,基于灰理论对EFP战斗部药型罩参数和成型性能参数进行了灰关联分析,得到了影响EFP性能参数的关联度矩阵,利用关联度矩阵指导了EFP战斗部的药型罩参数选择设计。数值仿真结果表明：影响EFP速度的主要因素依次为药型罩维角、材料密度、壁厚,影响EFP长径比的主要因素依次为药型罩材料密度、锥角、壁厚,而且基于灰关联分析结果设计的40 mm EFP战斗部,可以形成高速且具有良好气动外形的EFP,利于提高战斗部毁伤性能。     

隔栅对EFP破片成型及侵彻的影响

采用在成型装药前端加装金属隔栅的方法形成爆炸成型弹丸(EFP)破片模态,利用LS-DYNA程序仿真研究了隔栅对EFP破片成型及侵彻的影响,得到隔栅位置和结构对形成EFP破片速度和飞散情况的影响规律。研究结果表明,隔栅单元格边长为0.2倍装药口径、隔栅与药型罩端部之间的距离为1/12倍装药口径时,形成的EFP破片速度和散布面积较佳。采用优化的隔栅结构进行试验,试验与数值模拟结果吻合较好,说明该文结果可为多模成型装药的进一步研究提供参考。     

地雷战斗部爆炸成型弹丸速度影响因素

采用LS-DYNA3D对K．Weimann等人做的爆炸成型弹丸实验进行了数值模拟,其模拟结果与实验结果具有较好的一致性。在此模拟的基础上着重分析了装药长径比、壳体厚度、药型罩壁厚对爆炸成型弹丸速度的影响规律,得到了有关爆炸成型弹丸成型速度关系式,为优化爆炸成型弹丸设计提供参考。     

铝药型罩环形聚能射流的数值模拟

基于一种药型罩材料为铝的环形聚能装药结构,通过Autodyn软件模拟不同起爆方式（起爆环直径D₁）和不同长径比（L/D）的装药,计算得到环形射流的成型过程和速度分布曲线.分析数值模拟结果发现:环形射流成型过程主要受长径比影响,长径比较小时射流发生内偏,长径比较大时射流发生外偏;射流轴向速度主要受长径比影响,长径比越大轴向速度越大,头部轴向速度最大相差约700 m/s;射流径向速度主要受起爆方式影响,平均径向速度最大相差为220 m/s,起爆环直径和长径比在较小或较大时,射流径向速度梯度较大;结合射流成型和速度结果,D₁=0.5D、L/D=1.0时射流综合性能较好.侵彻混凝土板试验的通孔直径为装药直径的2.6倍,数值模拟结果与试验结果误差为7.7%,验证了计算模型及算法的合理性.      

药型罩壁厚对周向MLEFP成型影响的数值模拟

为提高防空反导弹药和反轻型装甲目标弹药的毁伤效能,提出了一种新型周向多线性爆炸成型弹丸(MLEFP)战斗部结构。在应用ANSYS/LS-DYNA有限元软件模拟MLEFP战斗部形成过程的基础上,分析了药型罩壁厚对周向MLEFP成型的影响规律。结果表明,在爆炸载荷作用下,新型周向MLEFP战斗部结构能够在4个方向上形成具有一定速度和长度的线性爆炸成型弹丸(LEFP),具有命中精度高、毁伤概率大、后效显著的特点,可以实现从四周进行近距离拦截和引爆来袭导弹、毁伤轻型装甲目标的目的,当药型罩壁厚与装药直径比取为0.05≤δ/D≤0.062时,形成的LEFP速度高、密实度好、毁伤效能好。     

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.     

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     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

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

正~~