期刊文献+
共找到5,929篇文章
< 1 2 250 >
每页显示 20 50 100
The heterogeneous impact of China-Europe railway express on the efficiency of logistics industry in node cities
1
作者 Yanliang Niu Jin Liu +1 位作者 Xining Yang Chuan Wang 《Railway Sciences》 2024年第3期279-294,共16页
Purpose-The spatiotemporal compression effect of China-Europe Railway Express(CR-Express)can reduce the filow costs of resources between China's node cities.Additionally,it can break through the limitations of low... Purpose-The spatiotemporal compression effect of China-Europe Railway Express(CR-Express)can reduce the filow costs of resources between China's node cities.Additionally,it can break through the limitations of low-added-value marine products,significantly impacting the logistics industry efficiency.However,there are few literature verifying and analyzing its heterogeneity.This study explores the impact of CR-Express on the efficiency of logistics industry in node cities and analyzes the heterogeneity.Design/methodology/approach-First,this study uses panel data to measure the efficiency of node city logistics industry.Secondiy,this study discusses the impact of the opening of CR-Express on the efficiency of logistics industry in node cities based on the multi-period differential model.Finally,according to the node city difference,the sample city experimental group is grouped for heterogeneity analysis.Findings-The results show that CR-Express can promote the urban logistics industry efficiency,with an average effect of 4.55%.According to the urban characteristics classification,the heterogeneity analysis shows that the efficiency improvement effect of logistics industry in inland cities is more obvious.The improvement effect of node cities and central cities in central and western China is stronger,especially in the sample of megacities and type I big cities.Compared with non-value chain industrial products,the CR-Express has significant promotion effects on the logistics efficiency of the cities where main goods are value chain products.Originality/value-Under the background of double cycle development,this paper can provide a scientific basis for the investment benefit evaluation of CR-Express construction and the follow-up route planning. 展开更多
关键词 Logistics industry efficiency china-europe railway express Difference-in-difference model HETEROGENEITY Transportation infrastructure Paper type Research paper
下载PDF
China-Europe Freight Train Promotes Bilateral Trade 被引量:1
2
作者 Liu Xinwei 《China's Foreign Trade》 2016年第6期34-35,共2页
On October 8,the'Belt and Road'Leading Group office published the'ChinaEurope Freight Train Development Plan',which is a fiveyear plan in accordance with China’s13th'Five-Year Plan'.The docume... On October 8,the'Belt and Road'Leading Group office published the'ChinaEurope Freight Train Development Plan',which is a fiveyear plan in accordance with China’s13th'Five-Year Plan'.The document formulated the major tasks for the construction of China-Europe freight train project for the next five years,and clarified three space layouts,including the China-Europe 展开更多
关键词 china-europe Freight Train Promotes Bilateral Trade
下载PDF
Jet formation and penetration performance of a double-layer charge liner with chemically-deposited tungsten as the inner liner 被引量:2
3
作者 Bihui Hong Wenbin Li +2 位作者 Yiming Li Zhiwei Guo Binyou Yan 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第3期374-385,共12页
This paper proposes a type of double-layer charge liner fabricated using chemical vapor deposition(CVD)that has tungsten as its inner liner.The feasibility of this design was evaluated through penetration tests.Double... This paper proposes a type of double-layer charge liner fabricated using chemical vapor deposition(CVD)that has tungsten as its inner liner.The feasibility of this design was evaluated through penetration tests.Double-layer charge liners were fabricated by using CVD to deposit tungsten layers on the inner surfaces of pure T2 copper liners.The microstructures of the tungsten layers were analyzed using a scanning electron microscope(SEM).The feasibility analysis was carried out by pulsed X-rays,slug-retrieval test and static penetration tests.The shaped charge jet forming and penetration law of inner tungsten-coated double-layer liner were studied by numerical simulation method.The results showed that the double-layer liners could form well-shaped jets.The errors between the X-ray test results and the numerical results were within 11.07%.A slug-retrieval test was found that the retrieved slug was similar to a numerically simulated slug.Compared with the traditional pure copper shaped charge jet,the penetration depth of the double-layer shaped charge liner increased by 11.4% and>10.8% respectively.In summary,the test results are good,and the numerical simulation is in good agreement with the test,which verified the feasibility of using the CVD method to fabricate double-layer charge liners with a high-density and high-strength refractory metal as the inner liner. 展开更多
关键词 Shaped charge Chemical vapor deposition TUNGSTEN Double-layer charge liner X-ray PENETRATION
下载PDF
Comparison of Human Rights Values Between the East and the West——Summary of the 2019 China-Europe Seminar on Human Rights 被引量:1
4
作者 李蕾 滕锐 PAN Yingzhao(译) 《The Journal of Human Rights》 2019年第5期695-707,共13页
The 2019 China-Europe Seminar on Human Rights hosted by the China Society for Human Rights Studies and Austria-China Friendship Association was successfully held in Austria on June 21,2019.Through this conference,Chin... The 2019 China-Europe Seminar on Human Rights hosted by the China Society for Human Rights Studies and Austria-China Friendship Association was successfully held in Austria on June 21,2019.Through this conference,China,as an important representative of Eastern countries of human rights,demonstrated its fruitful theoretical and practical human rights achievements to European countries.The conference also witnessed lively communication and exchanges on human rights values and the human rights discourse system between China and the West,during which scholars of the East and the West discussed the universality and particularity of human rights,and the evolution of human rights under different historical and cultural values.The conference advocated that the concept of a community with a shared future for human beings proposed by China should be incorporated into human rights governance of sovereign states and the international community.The convergence and integration of the human rights concepts of the East and the West will inevitably lead human rights practices of the East and the West to embark on a new journey. 展开更多
关键词 the east and the WEST china-europe human RIGHTS values
下载PDF
Research on the Construction of China-Europe Cross-border E-com-merce Ecosphere Based on Blockchain Technology
5
作者 Liang Liu Xiaoyu Jiang Jian Wu 《Journal of Finance Research》 2019年第1期11-15,共5页
Based on the blockchain technology to construct the relevant research on the China-Europe cross-border e-commerce ecosystem,we must first define the main significance and combine the core technology application of blo... Based on the blockchain technology to construct the relevant research on the China-Europe cross-border e-commerce ecosystem,we must first define the main significance and combine the core technology application of blockchain to explore the blockchain China-Europe cross-border e-commerce ecosystem,thereby drawing effective measures such as establishing a cross-border e-commerce integrated service system,improving e-commerce credit risk management and establishing a blockchain supply chain intelligence system,which comprehensively elaborates on the importance of blockchain technology to build a China-Europe cross-border e-commerce ecosystem. 展开更多
关键词 Blockchain TECHNOLOGY TECHNOLOGY CONSTRUCTION china-europe CROSS-BORDER cooperation E-COMMERCE
下载PDF
Modernization and the Diversity of Human Rights Among Civilizations--Review of the 2023 China-europe Seminar on Human Rights
6
作者 谭堾垿 LIU Haile(Translated) 《The Journal of Human Rights》 2023年第6期1373-1386,共14页
Human rights are an achievement of humanity and a symbol of progress.Respect for and protection of human rights are basic principles of modern civilization.Around the world,countries and regions have chosen different ... Human rights are an achievement of humanity and a symbol of progress.Respect for and protection of human rights are basic principles of modern civilization.Around the world,countries and regions have chosen different paths to modernization,which are rooted in their unique civilizations.to promote exchanges and mutual learning among civilizations,facilitate human rights exchanges and cooperation between different countries,and advance the global development of human rights,on September 20,2023,the 2023 China-europe Seminar on Human Rights was held in Rome,the capital of Italy.Under the theme of“Modernization and the Diversity of Human Rights Among Civilizations,”the seminar focused on discussing topics such as exchanges and mutual learning among civilizations and the development of modern human rights philosophy,modernization and the free and well-rounded development of every person,sustainable development in the process of modernization,and the evolution of the civilization of human rights in the digital age.participants reached the following consensuses at the event:First,the participants from various countries spoke highly of the great achievements that China has made in human rights cause and fully recognized China’s contributions in promoting the development and progress of the global human rights cause;Second,the participants from all countries agreed that it is necessary to discard the concept of“Western-centrism,”transcend the mindset of“cultural superiority,”promote human rights exchanges and mutual learning among civilizations on the basis of equality and mutual respect,and inject new impetus into the diversity of human rights among civilizations;third,participants reaffirmed that human rights represent an open concept,and that we should discuss the development of human rights with an open mind and jointly promote the progress of human rights in the world. 展开更多
关键词 china-europe Seminar on Human Rights modern-ization diversity of human rights among civilizations sustainable development digital human rights
下载PDF
Integrated design and control technology of liner completion and drilling for horizontal wells
7
作者 GAO Deli XIAN Baoan BI Yansen 《Petroleum Exploration and Development》 SCIE 2024年第4期1009-1021,共13页
Aiming at the problems of large load of rotation drive system,low efficiency of torque transmission and high cost for operation and maintenance of liner steering drilling system for the horizontal well,a new method of... Aiming at the problems of large load of rotation drive system,low efficiency of torque transmission and high cost for operation and maintenance of liner steering drilling system for the horizontal well,a new method of liner differential rotary drilling with double tubular strings in the horizontal well is proposed.The technical principle of this method is revealed,supporting tools such as the differential rotation transducer,composite rotary steering system and the hanger are designed,and technological process is optimized.A tool face control technique of steering drilling assembly is proposed and the calculation model of extension limit of liner differential rotary drilling with double tubular strings in horizontal well is established.These results show that the liner differential rotary drilling with double tubular strings is equipped with measurement while drilling(MWD)and positive displacement motor(PDM),and directional drilling of horizontal well is realized by adjusting rotary speed of drill pipe to control the tool face of PDM.Based on the engineering case of deep coalbed methane horizontal well in the eastern margin of Ordos Basin,the extension limit of horizontal drilling with double tubular strings is calculated.Compared with the conventional liner drilling method,the liner differential rotary drilling with double tubular strings increases the extension limit value of horizontal well significantly.The research findings provide useful reference for the integrated design and control of liner completion and drilling of horizontal wells. 展开更多
关键词 horizontal well liner completion and drilling double tubular strings liner differential rotary drilling tool face control horizontal extension limit
下载PDF
3D Roughness Prediction Modeling and Evaluation of Textured Liner of Piston Component-Cylinder System
8
作者 Yanjun Lü Cheng Liu +3 位作者 Yongfang Zhang Cheng Jiang Xudong Bai Zhiguo Xing 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2024年第5期203-215,共13页
In this study,a machine vision method is proposed to characterize 3D roughness of the textured surface on cylinder liner processed by plateau honing.The least absolute value(L∞)regression robust algorithm and Levenbe... In this study,a machine vision method is proposed to characterize 3D roughness of the textured surface on cylinder liner processed by plateau honing.The least absolute value(L∞)regression robust algorithm and Levenberg-Marquardt(LM)algorithm are employed to reconstruct image reference plane.On this basis,a single-hidden layer feedforward neural network(SLFNN)based on the extreme learning machine(ELM)is employed to model the relationship between high frequency information and 3D roughness.The characteristic parameters of Abbott-Firestone curve and 3D roughness measured by a confocal microscope are used to construct ELM-SLFNN prediction model for 3D roughness.The results indicate that the proposed method can effectively characterize 3D roughness of the textured surface of cylinder liner. 展开更多
关键词 Surface texture Cylinder liner 3D roughness Neural network
下载PDF
Machine learning optimization strategy of shaped charge liner structure based on jet penetration efficiency
9
作者 Ziqi Zhao Tong Li +6 位作者 Donglin Sheng Jian Chen Amin Yan Yan Chen Haiying Wang Xiaowei Chen Lanhong Dai 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第9期23-41,共19页
Shaped charge liner(SCL)has been extensively applied in oil recovery and defense industries.Achieving superior penetration capability through optimizing SCL structures presents a substantial challenge due to intricate... Shaped charge liner(SCL)has been extensively applied in oil recovery and defense industries.Achieving superior penetration capability through optimizing SCL structures presents a substantial challenge due to intricate rate-dependent processes involving detonation-driven liner collapse,high-speed jet stretching,and penetration.This study introduces an innovative optimization strategy for SCL structures that employs jet penetration efficiency as the primary objective function.The strategy combines experimentally validated finite element method with machine learning(FEM-ML).We propose a novel jet penetration efficiency index derived from enhanced cutoff velocity and shape characteristics of the jet via machine learning.This index effectively evaluates the jet penetration performance.Furthermore,a multi-model fusion based on a machine learning optimization method,called XGBOOST-MFO,is put forward to optimize SCL structure over a large input space.The strategy's feasibility is demonstrated through the optimization of copper SCL implemented via the FEM-ML strategy.Finally,this strategy is extended to optimize the structure of the recently emerging CrMnFeCoNi high-entropy alloy conical liners and hemispherical copper liners.Therefore,the strategy can provide helpful guidance for the engineering design of SCL. 展开更多
关键词 Jet penetration efficiency Shaped charge liner FEM-ML XGBOOST MFO High-entropy alloy
下载PDF
Simulation Study of Solid Rocket Motor C/C Throat Liner Ablation Based on Two Regions
10
作者 Guanneng Chen Yihua Xu +2 位作者 Xiaojiang Zha Hemeng Shi Bing Liu 《Journal of Power and Energy Engineering》 2024年第4期1-19,共19页
Based on the ablation micro-morphological characteristics, thermo-chemical ablation mechanism, and mechanical stripping mechanism, a dual-region solid rocket motor C/C throat liner ablation model and physical model ar... Based on the ablation micro-morphological characteristics, thermo-chemical ablation mechanism, and mechanical stripping mechanism, a dual-region solid rocket motor C/C throat liner ablation model and physical model are established. The ablation program was written and the experimental data of 70 lb BATES engine platform was used for model validation. The relative errors between the simulation calculation results and the experimental results were −6.83% - 10.20%. The ablation program was applied to study the effects of combustion chamber temperature, pressure, oxidation component concentration, throat particle concentration and particle scouring angle on the nozzle throat liner, which provides a reference for the design of the nozzle throat liner and the estimation of solid rocket motor ablation. 展开更多
关键词 Dual-Area Ablation Model C/C Throat liner Ablation Environment Ablation Program
下载PDF
磁驱动固体套筒实验模拟中的电流系数
11
作者 阚明先 陈涵 +4 位作者 吴凤超 贾月松 张南川 傅贞 段书超 《高压物理学报》 CAS 北大核心 2025年第1期79-85,共7页
采用不可压缩理论模型,对FP-2装置上开展的磁驱动固体套筒实验进行了模拟分析。模拟结果表明,无论是二维磁流体力学理论模型,还是其他不可压缩理论模型,回流罩结构磁驱动固体套筒的边界磁感应强度公式中都包含一个小于1的套筒电流系数... 采用不可压缩理论模型,对FP-2装置上开展的磁驱动固体套筒实验进行了模拟分析。模拟结果表明,无论是二维磁流体力学理论模型,还是其他不可压缩理论模型,回流罩结构磁驱动固体套筒的边界磁感应强度公式中都包含一个小于1的套筒电流系数。对不同套筒厚度、不同套筒半径条件下磁驱动固体套筒实验的电流系数进行了模拟,发现电流系数不仅与套筒内半径有关,还与套筒厚度有关;套筒内半径越大,套筒电流系数越小;套筒厚度越大,套筒电流系数越小。准确掌握磁驱动固体套筒电流系数的变化规律,可使磁流体程序从磁驱动固体套筒实验的后验模拟发展为精确预测,使磁流体力学模型真正具备正确设计和指导磁驱动固体套筒相关实验的理论能力。 展开更多
关键词 磁驱动固体套筒实验 二维磁驱动数值模拟程序 磁流体力学 电流系数 回流罩结构
下载PDF
非对称中空环形聚能装药成型与侵彻特性影响因素分析
12
作者 李召婷 王树有 +2 位作者 孙圣杰 蒋建伟 门建兵 《爆炸与冲击》 EI CAS 北大核心 2025年第1期41-50,共10页
为减弱中空环形聚能装药形成的中心侵彻体对后级结构的破坏作用,通过改变环锥罩的偏心距离和壁厚,调整了装药和药型罩的质量分布,使之形成准直环形射流,研究了炸高对环形射流侵彻威力的影响规律。数值模拟结果表明:内壳为铝合金时的中... 为减弱中空环形聚能装药形成的中心侵彻体对后级结构的破坏作用,通过改变环锥罩的偏心距离和壁厚,调整了装药和药型罩的质量分布,使之形成准直环形射流,研究了炸高对环形射流侵彻威力的影响规律。数值模拟结果表明:内壳为铝合金时的中心孔平均侵彻深度较内壳为钢时的平均侵彻深度低36.13%;非偏心环锥罩形成的射流存在径向偏移,侵彻能力较弱。当环锥罩顶向外侧偏移0.05d(d为环形装药厚度)时,射流准直性较好,环形射流侵彻深度较大;随着药型罩壁厚的增加,射流头部速度不断减小,当壁厚为0.045d时,偏心环锥罩形成的环形射流侵彻能力较强;环形射流侵彻深度对炸高较为敏感,在炸高为1.12d时,环形射流侵彻深度较大。针对非偏心环锥罩和偏心环锥罩两种药型罩结构开展的静破甲试验表明,环形射流侵彻深度和扩孔直径的试验结果与数值模拟结果误差小于12%,验证了数值模拟模型的可靠性。 展开更多
关键词 环形聚能装药 偏心药型罩 射流成型 射流侵彻
下载PDF
TSL(Thin spray-on liners)材料在巷道支护中的应用 被引量:7
13
作者 史玲 《中国矿业》 北大核心 2011年第3期90-93,101,共5页
TSL(Thin Spray-on Liners)材料作为一种最新的支护材料,在矿山巷道中开始逐渐得到应用,在某些地区已经作为一种标准支护手段来取代喷网支护。这种大概4mm厚的喷层,能有效的支护松散岩体,增强其他支护结构的作用效果,并能保护锚杆锚网... TSL(Thin Spray-on Liners)材料作为一种最新的支护材料,在矿山巷道中开始逐渐得到应用,在某些地区已经作为一种标准支护手段来取代喷网支护。这种大概4mm厚的喷层,能有效的支护松散岩体,增强其他支护结构的作用效果,并能保护锚杆锚网等金属材料免受侵蚀。实验表明,在高地应力情况下,还能有效的减少岩爆的破坏。目前市场上有多种TSL产品,其材料性能及实验手段也在不断的发展完善。本文主要介绍TSL材料在巷道支护中的作用机理及在不同受力状态下材料的性能相关测试实验。 展开更多
关键词 TSL材料 巷道支护 实验室研究
下载PDF
组合-填充药型罩成型及侵彻靶板数值模拟
14
作者 张卿尚 王志军 +3 位作者 伊建亚 何卓朗 太忻 贺磊 《火工品》 CAS 北大核心 2025年第1期44-50,共7页
针对聚能射流侵彻披挂爆炸反应装甲坦克顶部装甲的高效毁伤问题,提出了一种新型的组合-填充药型罩结构。采用非线性动力学分析软件AUTODYN-2D对射流形成和侵彻靶板过程进行了数值模拟,并分析了填充物材料和起爆方式对射流成型的影响以... 针对聚能射流侵彻披挂爆炸反应装甲坦克顶部装甲的高效毁伤问题,提出了一种新型的组合-填充药型罩结构。采用非线性动力学分析软件AUTODYN-2D对射流形成和侵彻靶板过程进行了数值模拟,并分析了填充物材料和起爆方式对射流成型的影响以及炸高对侵彻性能的影响。研究结果表明:所提出的组合-填充药型罩可以形成首尾相连的两级串联射流,填充物采用铝和特氟龙时射流成型效果较好,但铝成型更加稳定;点环起爆形成的射流动能比单独点起爆形成的前级射流动能提高67.06%,后级射流动能提高29.51%;在炸高区间为2~6 CD(装药直径)时,成型射流均可以侵彻披挂爆炸反应装甲的坦克顶甲,并保持一定的剩余头部速度,且最佳炸高为5 CD。本研究对反披挂爆炸反应装甲坦克顶甲的新结构药型罩设计具有参考意义。 展开更多
关键词 药型罩 爆炸反应装甲 填充物 起爆方式 炸高 数值模拟
下载PDF
APPLICATION OF HOT-PRESS SINTERING TECHNIQUE TO EXPLOSIVE CHARGE LINER OF PETROLEUM PERFORATION BULLET
15
作者 刘奎 左敦稳 王珉 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 1998年第2期78-83,共6页
A new method for manufacturing explosive charge liner of petroleum perforation bullet, using hot press sintering technique, has been introduced in the paper. The sintering process of making explosive charge liner has... A new method for manufacturing explosive charge liner of petroleum perforation bullet, using hot press sintering technique, has been introduced in the paper. The sintering process of making explosive charge liner has been investigated. The mechanical test and SEM analysis indicate that the property of the liner produced by the process is satisfied. 展开更多
关键词 hot press sintering petroleum perforation bullet sintering process explosive charge liner
下载PDF
环形复合内衬头盔冲击波防护性能研究
16
作者 贾时雨 王成 +2 位作者 徐文龙 马东 齐方方 《兵工学报》 北大核心 2025年第1期58-67,共10页
冲击波防护能力是单兵头盔的主要性能指标,对提高单兵战场生存能力具有重要意义。为了提高单兵头盔的冲击波防护性能,针对先进战斗头盔内衬的结构以及布置方式展开探索,提出环形聚脲-聚氨酯泡沫-海绵复合材料外沿内衬设计,并进行防护性... 冲击波防护能力是单兵头盔的主要性能指标,对提高单兵战场生存能力具有重要意义。为了提高单兵头盔的冲击波防护性能,针对先进战斗头盔内衬的结构以及布置方式展开探索,提出环形聚脲-聚氨酯泡沫-海绵复合材料外沿内衬设计,并进行防护性能评估。通过激波管和实爆,针对有/无头盔以及装配不同结构及尺寸外沿内衬头盔的冲击波防护性能展开测试,对前额、颅顶及后脑3个重点区域位置表面的冲击波波形以及压力峰值进行对比分析。实验结果表明:佩戴头盔后冲击波主要通过头-头盔间隙以绕射的形式进入并作用于头部表面,间隙内冲击波聚集叠加反而可能会使压力增强,且由于叠加汇聚效应往往导致距离爆源较远的位点,容易形成局部高压区;环形聚脲-聚氨酯泡沫-海绵复合材料外沿内衬可以有效阻挡绕射波进入头盔内部、减弱绕射波叠加效应,各测点冲击波超压衰减率均可达40%以上;在所采用的入射冲击波(弱冲击波)条件下,冲击波作用过程中形成的间隙越小,防护效果越好;当聚脲-聚氨酯泡沫材料宽度为15 mm时外沿内衬与头模贴合程度最好且防护效果最优,外场爆炸实验结果显示,前额、颅顶和后脑位置超压衰减率分别可高达92.26%、88.82%和87.19%。 展开更多
关键词 头盔 冲击波防护 外沿内衬 爆炸冲击波 激波管
下载PDF
包覆式活性EFP成型机理与规律研究
17
作者 别海远 张鸿宇 +2 位作者 马红兵 邱文豪 郑元枫 《兵工学报》 北大核心 2025年第1期79-87,共9页
为研究包覆式活性爆炸成型弹丸(Explosively Formed Projectiles,EFP)成型机理及药型罩结构对成型行为的影响规律,采用Lagrange和Euler组合算法开展包覆式活性EFP成型过程数值模拟。数值模拟结果首先揭示包覆式活性EFP成型机理,其典型... 为研究包覆式活性爆炸成型弹丸(Explosively Formed Projectiles,EFP)成型机理及药型罩结构对成型行为的影响规律,采用Lagrange和Euler组合算法开展包覆式活性EFP成型过程数值模拟。数值模拟结果首先揭示包覆式活性EFP成型机理,其典型包覆成型过程主要包括轴向双罩碰撞阶段、径向包覆闭合阶段和金属前驱侵彻体拉伸阶段。在轴向双罩碰撞阶段,双罩通过多次碰撞-分离-碰撞过程,实现轴向加速和动能传递;在径向包覆闭合阶段,金属罩向前折叠,其后部实现对活性罩完全包覆,前部形成速度梯度明显的金属前驱侵彻体;随后,金属前驱侵彻体随时间逐渐拉伸,甚至断裂。进一步得到紫铜罩和活性罩形状参数对包覆成型的影响规律,随紫铜罩边缘厚度从2.0 mm减小到0.5 mm,包覆闭合时间从57.9μs减小到23.9μs,同时头部速度从1851 m/s增大到2370 m/s,侵彻体长度从76 mm增大到110.5 mm;随紫铜罩曲率半径从60 mm减小到40 mm,包覆闭合时间从42.1μs减小到28.1μs,同时头部速度从1789 m/s增大到2242 m/s,侵彻体长度从66 mm增大到100 mm;随活性罩厚度由6 mm减小至2 mm,包覆时间从52.0μs减小至32.1μs,活性罩质量从6.47 g降低至2.37 g;随活性罩直径由32 mm减小至16 mm,包覆时间从34.4μs减小至30.8μs,活性罩质量从6.42 g降低为1.61 g。研究结果可为包覆式活性EFP聚能装药设计提供指导和参考。 展开更多
关键词 聚能装药 药型罩 成型行为 活性材料 包覆式EFP
下载PDF
Analysis of diffusion-adsorption equivalency of landfill liner systems for organic contaminants 被引量:9
18
作者 XIE Haijian, CHEN Yunmin, KE Han, TANG Xiaowu, CHEN Renpeng MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering, Zhejiang University, Hangzhou 310027, China. 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2009年第4期552-560,共9页
The equivalence between multilayered barriers regarding diffusion and adsorption was studied. The bottom boundary of the liner system is defined by assuming concentration continuous and flux continuous conditions of t... The equivalence between multilayered barriers regarding diffusion and adsorption was studied. The bottom boundary of the liner system is defined by assuming concentration continuous and flux continuous conditions of the contaminant between the bottom liner layer and the underlying soil. Five different liner systems were compared in terms of solute breakthrough time. The results of the analysis showed that breakthrough time of the hydrophobic organic compounds for a 2-meter-thick compacted clay liner (CCL) could be 3-4 orders of magnitude is greater than the breakthrough time for a geosynthetic clay liner (GCL) composite liner. The GM/GCL and GM/CCL composite liner systems provide a better diffusion barrier for the hydrophilic organic compounds than that for the hydrophobic compounds due to their different Henry's coefficient. The calculated breakthrough times of the organic contaminants for the Chinese standard liner systems were found to be generally greater than those for the GCL alternatives, for the specific conditions examined. If the distribution coefficient increases to 2.8 for the hydrophobic compounds or 1.0 for the hydrophilic compounds, the thickness of the attenuation layer needed to achieve the same breakthrough time as the standard liner systems can be reduced by a factor of about 1.9-2.4. As far as diffusive and adsorption contaminant transport are concerned, GM or GCL is less effective than CCL. 展开更多
关键词 liner system equivalency organic contaminant LANDFILL DIFFUSION ADSORPTION
下载PDF
Effects of Friction Heat on the Tribological Properties of the Woven Self-lubricating Liner 被引量:12
19
作者 YANG Yulin ZU Dalei +1 位作者 ZHANG Ruijun QI Xiaowen 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2009年第6期918-924,共7页
In the dry-sliding process of the woven self-lubricating liner which is used in the self-lubricating spherical plain bearing, the friction heat plays an important role in the tribological performances of the liner. It... In the dry-sliding process of the woven self-lubricating liner which is used in the self-lubricating spherical plain bearing, the friction heat plays an important role in the tribological performances of the liner. It has important value to study on the relationship between tribological performances of the liner and the friction heat. Unforttmately, up to now, published work on this relationship is quite scarce. Therefore, the effect of friction heat on the tribological performances of the liner was investigated in the present work. The tribological behaviors of the liner were evaluated by using the high temperature end surface wear tester. Scanning electron microscopy (SEM) was utilized to examine the morphologies of worn surfaces of the liner and study the failure modes. Differential scanning calorimetry (DSC) measurement and X-ray diffraction (XRD) analysis were performed to study the behaviors of the wear debris. The temperature rise on the worn surface was calculated according to classical models. SEM observation shows that the dominating wear mechanism for the liner is mainly affected by friction shear force, contact pressure and friction heat. Higher fusion heat for the wear debris than that for the pure polytetrafluroethylene (PTFE) indicates that the PTFE is the main portion of the wear debris, and, the PTFE in the wear debris shows a higher crystallisation degree owing to the effects of friction shear force and the friction heat. Combining the calculated temperature rise results with the wear rate of the liner, it can be concluded that the effects of temperature rise o n the tribological performances of the liner become more obvious when the temperature rise exceeds the glass transition temperature (Tg) of the PTFE. The wear resistance of the liner deteriorates dramatically when the temperature rise approaches to the melting point (Ton) of the PTFE. The tribological performances of the liner can be improved when the temperature rise exceeds Tg but is far lower than Ton- The present study on the relationship between the temperature rise and the tribological performances of the liner may provide the basis for further understanding of the wear mechanisms of the liner as well as the relationship between the formation of the PTFE transfer film and the friction heat during the dry-sliding of the Finer. 展开更多
关键词 woven fabric self-lubricating liner friction and wear friction heat differential scanning calorimetry thermal analysis transfer film
下载PDF
Controlling strain in geosynthetic liner systems used in vertically expanded landfills 被引量:4
20
作者 Yunmin Chen Deng Gao Bin Zhu 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE 2009年第1期48-55,共8页
According to relevant new regulations in China,a composite liner system involving geosynthetic materials must be installed at the bottom of an expanded landfill.The deformation and integrity of the composite liner und... According to relevant new regulations in China,a composite liner system involving geosynthetic materials must be installed at the bottom of an expanded landfill.The deformation and integrity of the composite liner under a variety of factors are important issue to be considered in the design of a landfill expansion.In this paper,we investigate the strain distribution in geosynthetic materials within the composite liner system of expanded landfills,including strains in geosynthetic materials resulting from overall settlement and lateral movement of landfills,localized subsidence in landfills,and differential settlement around gas venting wells.The allowable strains of geosynthetic materials are discussed based on the results of tensile tests,and the corresponding design criteria for composite liner systems are proposed.Meanwhile,practical measures allowing strain control in geosynthetic materials used in landfill engineering are proposed. 展开更多
关键词 LANDFILL composite liner system GEOSYNTHETICS STRAIN
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部