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Experimental investigation of penetration performance of shaped charge into concrete targets

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Acta Mechanica Sinica 2008年第3期24卷 345-349页

作者： cheng Wang Tianbao ma Jianguo Ning State Key Laboratory of Explosion Science and Technology Beijing Institute of Technology Beijing 100081 China

In order to develop a tandem warhead that can effectively destroy concrete targets, this paper explores the penetration performance of shaped charges with different cone angles and liner materials into concrete targets by means of experiments. The penetration process and the destruction mechanism of concrete targets by shaped charges and kinetic energy projectiles are analyzed and compared. Experimental results suggest that both kinetic energetic projectile and shaped charge are capable of destroying concrete targets, but the magnitudes of damage are different. Compared with a kinetic energy projectile, a shaped charge has more significant effect of penetration into the target, and causes very large spalling area. Hence, a shaped charge is quite suitable for first-stage charge of tandem warhead. It is also found that, with the increase of shaped charge liner cone angle, the depth of penetration decreases gradually while the hole diameter becomes larger. Penetration depth with copper liner is larger than of aluminum liner but hole diameter is relatively smaller, and the shaped charge with steel liner is between the above two cases. The shaped charge with a cone angle of 100° can form a jet projectile charge （JPC）. With JPC, a hole with optimum depth and diameter on concrete targets can be formed, which guarantees that the second-stage warhead smoothly penetrates into the hole and explodes at the optimum depth to achieve the desired level of destruction in concrete targets.

关键词： Shaped charge JPC Kinetic energy projectile Concrete Penetration

Experimental Investigations on the Out-of-Plane Sub-harmonic Vibration of a Circular Dielectric Elastomer Actuator

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Acta Mechanica Solida Sinica 2019年第5期32卷 591-598页

作者： cheng ma Meng Yang Kun Jia Tongqing Lu State Key Laboratory for Strength and Vibration of Mechanical Structure Department of Engineering MechanicsXi'an Jiaotong UniversityXi'an 710049China

Dielectric elastomers have found interesting applications in soft loudspeakers,where vibrations subject to alternating electrical excitations are the key *** there are many t heore tical studies on the nonlinear vibrations of dielec trie elasto mers subject to electromechanical coupling loads,the systematic experimental research is *** this work,we design a simple experimental setup to observe the out-of-plane vibrations of a circular dielec trie elastomer *** find that the dielec trie elastomer has different response modes including the harmonic,super-harmonic and sub-harmonic responses at different excitation *** analyze the responses by using the short-time Fourier *** find that the equivalent voltage and the AC/DC ratio are the main parameters affecting the occurrence of sub-harmonic *** phenomenon of mode shift is also observed in our *** experimental observations provide a deeper unders tanding of the dynamic responses of dielec trie elasto mer subject to electromechanical loads.

关键词： Dielectric elastomer Nonlinear vibration Harmonic response Sub-harmonic response

Novel Models and Algorithms of Load Balancing for Variable-structured Collaborative Simulation under HLA/RTI

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Chinese Journal of Mechanical Engineering 2013年第4期26卷 629-640页

作者： YUE Yingchao FAN Wenhui XIAO Tianyuan ma cheng State CIMS Engineering Research Center Tsinghua University

High level architecture(HLA) is the open standard in the collaborative simulation field. Scholars have been paying close attention to theoretical research on and engineering applications of collaborative simulation based on HLA/RTI, which extends HLA in various aspects like functionality and efficiency. However, related study on the load balancing problem of HLA collaborative simulation is insufficient. Without load balancing, collaborative simulation under HLA/RTI may encounter performance reduction or even fatal errors. In this paper, load balancing is further divided into static problems and dynamic problems. A multi-objective model is established and the randomness of model parameters is taken into consideration for static load balancing, which makes the model more credible. The Monte Carlo based optimization algorithm(MCOA) is excogitated to gain static load balance. For dynamic load balancing, a new type of dynamic load balancing problem is put forward with regards to the variable-structured collaborative simulation under HLA/RTI. In order to minimize the influence against the running collaborative simulation, the ordinal optimization based algorithm(OOA) is devised to shorten the optimization time. Furthermore, the two algorithms are adopted in simulation experiments of different scenarios, which demonstrate their effectiveness and efficiency. An engineering experiment about collaborative simulation under HLA/RTI of high speed electricity multiple units(EMU) is also conducted to indentify credibility of the proposed models and supportive utility of MCOA and OOA to practical engineering systems. The proposed research ensures compatibility of traditional HLA, enhances the ability for assigning simulation loads onto computing units both statically and dynamically, improves the performance of collaborative simulation system and makes full use of the hardware resources.

关键词： static load balancing dynamic load balancing variable-structure collaborative simulation under HLA/RTI multi-objective optimization ordinal optimization

Ti/Fe EUTECTIC REACTION PROCESS

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Chinese Journal of Mechanical Engineering 2006年第4期19卷 614-617页

作者： WU Mingfang ma cheng YANG Min Provincial Key Laboratory of Advanced Welding Technology Jiangsu University of Science and Technology Zhenjiang 212003 China School of materials Science and Engineering Jiangsu University of Science and Technology Zhenjiang 212003 China School of Naval Architecture and Ocean Engineering Jiangsu University of Science and Technology Zhenjiang 212003 China

To obtain satisfactory joining between titanium alloys end stainless steel, it is of great significance to study the process of Ti-Fe eutectic reaction. The preliminary studies about the liquid forming, spreading end the structure of the contact reaction between pure Ti and pure Fe are carried out at 1 120℃ for different holding times in high-frequency induction heated vacuum furnace. The results show that for Fe（particle-like）/Ti（plate-like） contact reaction couples, owing to Fe＇s higher density then titanium＇s, the Fe/Ti eutectic reaction develops in the thickness direction of plate-like Ti, named ＂deposition effect＂. Then the eutectic reaction can be realized without the inter-diffusion between Ti end Fe atoms, so the formation rate of the liquid phase is very quick. For Ti （particle-like）/ Fe （plate-like） contact reaction couples, the eutectic reaction has a strong direction, i.e. the eutectic liquid is formed mostly at the Ti side, which leads to much dissolution of Ti particle end very little dissolution of the Fe base metal. It can be seen that the diffusion rate of Fe in Ti determines the whole process of the eutectic reaction, behaved as that the dissolution rate of Ti （particle-like）/ Fe （plate-like） is much lower then that of Fe（particle-like）/Ti（plate-like）, end the dissolution rate of Ti obeys the square root law. Whatever means the Ti, Fe are assembled by, only dissolution process can be founded, the spread phenomena is unobvious, which is concerned with the formation of the inter- metallic compounds end the ＂deposition effect＂ of Fe.

关键词： Ti Fe Eutectic reaction Dissolution Spread

Solid-Phase Total Synthesis of 1-β-Methylcarbapenem

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Chinese Chemical Letters 2003年第1期14卷 6-8页

作者： Ming LEI cheng ma Yan Guang WANG Department of Chemistry Zhejiang UniversityHangzhou 310027

A 1-b-methylcarbapenem analogue 6 was synthesized on polystyrene-diethylsilane resin (PS-DES) using 2-azetidinone bearing with 2-oxazolidone chiral auxiliary as starting material.

关键词： Solid-phase synthesis of b-lactam carbapenem antibiotics.

4-(Benzylamino)formoyldiphenylammonium Triflate (BDPAT):An Efficient, Recoverable Biphasic Catalyst For Esterification of Carboxylic Acids with Equimolar Amounts of Alcohols

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Chinese Chemical Letters 2002年第6期13卷 487-488页

作者： Ming LEI cheng ma Yan Guang WANG Department of Chemistry Zhejiang UniversityHangzhou 310027

Esterification of carboxylic acid with equimolar amounts alcohol can be efficiently catalyzed by biphasic 4-(benzylamino)formoyldiphenylammonium triflate (BDPAT, 3) in good yield. The catalyst can be easily recovered... 详细信息

关键词： Benzylamino)formoyldiphenylammonium triflate biphasic catalyst esterification.

Multi-grained system integration for hybrid-paradigm brain-inspired computing

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Science China(Information Sciences) 2023年第4期66卷 272-285页

作者： Jing PEI Lei DENG cheng ma Xue LIU Luping SHI Department of Precision Instrument Center for Brain Inspired Computing Research(CBICR) Beijing Innovation Center for Future Chip Tsinghua University

Hybrid neuromorphic computing supporting the prevailing artificial neural networks and neuroscience-inspired models/algorithms offers substantial flexibility for cross-paradigm model *** is one of the most promising technologies for accelerating intelligence development, ultimately contributing to artificial general intelligence development. Recently, an increasing number of hybrid neuromorphic computing chips have been reported, but such research focuses on chip design without demonstrating systems for large-scale workloads. To this end, we construct a multi-grained system based on many Tianjic chips, presenting a large-scale system for hybrid-paradigm brain-inspired computing. With different numbers of chips and different connection topologies, we develop a Tianjic card and a Tianjic board as the infrastructure for building embedded systems and cloud servers, respectively. Extensive measurements of the communication latency, computational latency, and power consumption evidence the superior potential of Tianjic systems for exploring brain-inspired computing for artificial general intelligence.

关键词： brain-inspired computing multi-grained system integration hybrid paradigm Tianjic chip brain-inspired platform

Close-in weapon system planning based on multi-living agent theory

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Defence Technology（防务技术） 2022年第7期18卷 1219-1231页

作者： Tang Tang Yue Wang Li-juan Jia Jin Hu cheng ma School of Information and Electronic Beijing Institute of TechnologyBeijing100081China

The close-in weapon system(CIWS)is a combat system that faces a complex environment full of dynamic and unknown challenges,whose construction and planning require a systematic design *** agent(MLA)theory is a methodology for the combat system design,which uses the livelihood degree to evaluate the multi-dimensional long-term operational effectiveness of the system;whereas,there is still no uniform quantization framework for the livelihood degree,and the adjustment methods of livelihood degree need to be further *** this paper,we propose the uniform quantization framework for the livelihood degree and detailed discuss the methods of livelihood *** on the MLA theory,the multi-dimensional operational effectiveness of the missile-gun integrated weapon system(MGIWS)is analyzed,and the long-term combat effectiveness against the saturation attack is ***,the planning problem of the equipment deployment and configuration is *** objectives,including the overall livelihood degree and cost-effectiveness(CE),are proposed,and the optimization method based on genetic algorithm(GA)is studied for the planning problem.

关键词： Multi-living agent theory Close-in weapon system Effectiveness evaluation Livelihood degree Queueing system Missile-gun integrated weapon system

Microstructure and stress corrosion cracking of a SA508-309L/308L-316L dissimilar metal weld joint in primary pressurized water reactor environment

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Journal of materials Science & Technology 2020年第5期40卷 1-14页

作者： Lijin Dong cheng ma Qunjia Peng En-Hou Han Wei Ke Key Laboratory of Nuclear materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang110016China School of materials and Engineering Southwest Petroleum UniversityChengdu610500China

Stress corrosion cracking(SCC) of an SA508-309 L/308 L–316 L dissimilar metal weld joint in primary pressurized water reactor environment was investigated by the interrupted slow strain rate tension tests following a microstructure characterization. The 308 L weld metal shows a higher content of δ ferrite than the 309 L weld metal. In addition, no obvious Cr-depletion but carbides precipitation at δ phase boundaries was observed in both 308 L and 309 L weld metals. The slow strain rate tension tests showed that the SCC susceptibility of the base and weld metals of the dissimilar metal weld joint follows the order of SA508 < 308 L weld metal < the heat affected zone of 316 L base metal < 309 L weld *** higher SCC susceptibility of 309 L weld metal than that of 308 L weld metal is likely due to the lower content of δ ferrite. In addition, a preferential SCC initiation in the 309 L weld metal adjacent to 308 L weld metal is attributed to few carbides in this region.

关键词： Dissimilar metal weld joint Stress corrosion cracking Microstructure Primary pressurized water reactor environment Slow strain rate tension