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Study on jet formation behavior and optimization of trunconical hypercumulation shaped charge structure

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Defence Technology（防务技术） 2023年第3期21卷 196-206页

作者： Chao Ge Zhuojun Qu Jin Wang Die Hu Yong Zhang School of Mechatronical Engineering Beijing Institute of TechnologyBeijing100081China

Combining the methods of theoretical,numerical and experimental,this research focuses on the jet formation behavior and optimization of trunconical hypercumulation shaped charge structure.With the three-stage division,formation theory of trunconical hypercumulation shaped charge jet is established based on micro element method.By dimensional analysis,main control parameters are identified and their effect on jet formation are analyzed.Through numerical modelling and orthogonal optimization method,influence of the factors and their levels over the indicators of jet tip velocity and jet length as well as order of the significance of each factor and level are obtained.Penetration experiments of trunconical hypercumulation shaped charge based on the orthogonal optimization reveals its advantage over traditional conical shaped charge structure,and finally determines the optimal influence factor level combination.The research and results would provide useful guide for the design and application of trunconical hypercumulation shaped charge structure.

关键词： structure shaped charge

Trans-scale study on the thermal response and initiation of ternary fluoropolymer-matrix reactive materials under shock loading

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Defence Technology（防务技术） 2023年第3期21卷 184-195页

作者： Chao Ge Die Hu Jin Wang Qingbo Yu Haifu Wang Yuanfeng Zheng School of Mechatronical Engineering Beijing Institute of TechnologyBeijing100081China

To investigate the thermal response and initiation behavior of ternary fluoropolymer-matrix PTFE/Al/W reactive materials,a research combining shock loading tests and trans-scale modelling is conducted.On the basis of a good agreement of the numerically simulated and tested shock wave propagation,the significant impact of component ratios and particle sizes on the evolution of mesoscopic temperature,hot-spots and initiation is well characterized and analyzed.Results demonstrate that as the content of W increases,the range of mesoscopic high-temperature area increases and tends to distribute more uniform,while material with smaller W particles causes more intense particle deformation and larger temperature rise.The time to reach the critical temperature shows positive correlation to the content of W,while the critical temperature of hot-spots shows negative correlation to the particle size of W.For PTFE/Al/W of high density,with the increase of W particle size,the reaction rate decrease,however the time to reach the peak reaction rate shortens.

关键词： deformation shock loading

Establishment,Characterization and Expression Pattern of a Spleen Cell Line,SMSP,Derived from Turbot(Scophthalmus maximus)

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中国海洋大学学报:英文版 2023年第5期22卷 1403-1411页

作者： XUE Ting LIU Yiping ge Xuefeng LI chao School of Marine Science and Engineering Qingdao Agricultural UniversityQingdao 266109China

A turbot(Scophthalmus maximus)cell line named SMSP was obtained from the spleen.The origin of the cells was identified by morphology,chromosome number and COI gene.The optimal basic medium,serum concentration and growth temperature of the cells were detected.SMSP cell line is mainly composed of fibroblast-like cells.Most of the SMSP cells contained 44 chromosomes,and the sequence of COI gene confirmed that the cells were originated from turbot.The optimal culture conditions were 24℃,DMEM+10%FBS.The cell line had high transfection efficiency for siRNA and plasmid.After stimulation with lipopolysaccharide(LPS)or poly(I:C),the expressions of immune-related genes such as TNF-β,IL-12s,IL-10 and IL-1βwere up-regulated significantly in the early stage(Pgen in vitro.

关键词： Scophthalmus maximus cell line spleen pathogen-associated molecular patterns immunity

A hybrid data-mining framework for train rescheduling strategy pattern discovery

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Transportation Safety and Environment 2024年第1期6卷 56-67页

作者： Ruirui Chen Xuekai ge Ping Huang chao Wen School of Transportation&Logistics Southwest Jiaotong UniversityChengdu 611756China Department of IT Operational Technology CN RailWaterloo N2V2R1Canada

This study presents a hybrid data-mining framework based on feature selection algorithms and clustering methods to perform the pattern discovery of high-speed railway train rescheduling strategies(RSs).The proposed model is composed of two states.In the first state,decision tree,random forest,gradient boosting decision tree(GBDT)and extreme gradient boosting(XGBoost)models are used to investigate the importance of features.The features that have a high influence on RSs are first selected.In the second state,a K-means clustering method is used to uncover the interdependences between RSs and the influencing features,based on the results in the first state.The proposed method can determine the quantitative relationships between RSs and influencing factors.The results clearly show the influences of the factors on RSs,the possibilities of different train operation RSs under different situations,as well as some key time periods and key trains that the controllers should pay more attention to.The research in this paper can help train traffic controllers better understand the train operation patterns and provides direction for optimizing rail traffic RSs.

关键词： high-speed railway rescheduling strategy pattern discovery feature identification clustering algorithm

Ion acceleration at dipolarization fronts associated with the interchange instability in Earth's magnetotail

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Science China(Technological Sciences) 2020年第11期63卷 2375-2383页

作者： LU HaoYu ge YaSong SUN chao School of Space and Environment Beihang UniversityBeijing 100191China Institute of geology and geophysics Chinese Academy of SciencesBeijing 100029China

It has been confirmed that dipolarization fronts(DFs)are the result of the interchange instability in the Earth's magnetotail.In this paper,we use a Hall MHD model to simulate the evolution of the interchange instability that produces DFs along the leading edge.A test particle simulation is performed to study the physical phenomenon of ion acceleration at the DF.The numerical simulation indicates that almost all particles move earthward and dawnward and then drift to the tail.The DF-reflected ion population at the duskside appears earlier as a consequence of the asymmetric Hall electric field.Ions that are distributed in a dawn-dusk asymmetric semicircle behind the DF tend to be accelerated to higher energies(>13.5 keV).These high-energy particles eventually concentrate in the dawnside.Ions experience effective acceleration by the dawnward electric field,while they drift through the dawn flank at the front,toward the tail.

关键词： dipolarization fronts interchange instability ion acceleration Hall MHD simulation

Penetration and internal blast behavior of reactive liner enhanced shaped charge against concrete space

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Defence Technology（防务技术） 2022年第6期18卷 952-962页

作者： Hao Zhang Yuan-feng Zheng Qing-bo Yu Chao Ge Cheng-hai Su Hai-fu Wang State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing100081PR China

Penetration and internal blast behavior of reactive liner enhanced shaped charge against concrete space were investigated through experiments and simulations.The volume of the enclosed concrete space is about 15 m^(3).The reactive liner enhanced shaped charge utilizes reactive copper double-layered liner,which is composed of an inner copper liner and an outer reactive liner,while the reactive material liner is fabricated by PTFE/Al(Polytetrafluoroethylene/Aluminum)powders through cold-pressing and sintering.Static explosion experiments show that,compared with the shaped charge which utilizes copper liner,the penetration cavity diameter and spalling area of concrete by the novel shaped charge were enlarged to 2 times and 4 times,respectively.Meanwhile,the following reactive material had blast effect and produced significant overpressure inside the concrete closed space.Theoretical analysis indicates concrete strength and detonation pressure of reactive material both affect the penetration cavity diameter.To the blast behavior of reactive material inside the concrete space,developing TNT equivalence model and simulated on AUTODYN-3 D for analysis.Simulation results reproduced propagation process of the shock wave in concrete space,and revealed multi-peaks phenomenon of overpressure-time curves.Furthermore,the empirical relationship between the peak overpressure and relative distance for the shock wave of reactive material was proposed.

关键词： Shaped charge Penetration Blast Concrete Numerical simulation

Reaction characteristic of PTFE/Al/Cu/Pb composites and application in shaped charge liner

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Defence Technology（防务技术） 2022年第9期18卷 1578-1588页

作者： Huan-Guo Guo Yuan-feng Zheng Suo He Qing-Bo Yu Chao Ge Hai-fu Wang Beijing Institute of Technology Institution China

In this paper, the reaction characteristic and its application in shaped charge warhead of a novel reactive material, which introduced copper(Cu) and plumbum(Pb) into traditional polytetrafluoroethylene/aluminum(PTFE/Al), are studied. The thermal analysis and chemical reaction behavior of the PTFE/Al/Cu/Pb mixture are investigated by Differential Scanning Calorimetry(DSC),Thermo-gravimetry(TG), and Xray Diffraction(XRD) techniques. Then, the shaped charge liners with PTFE/Al/Cu/Pb reactive materials are fabricated, and the X-ray experiments show that they could form reactive jets with excellent performance under the detonation effects of the shaped charge. Based on that, the penetration experiments of shaped charge with PTFE/Al/Cu/Pb reactive liner against steel plates are carried out, and the results demonstrate that the PTFE/Al/Cu/Pb reactive jets could produce a deeper penetration depth compared to the traditional PTFE/Al reactive jets. Meanwhile, the PTFE/Al/Cu/Pb reactive jets also show significant inner-blast effects, leading to dramatically cracking or fragmentation behavior of the penetrated steel plates. This new PTFE/Al/Cu/Pb reactive liner shaped charge presents enhanced penetration behavior for steel targets that incorporates the penetration capability of a high-density and ductility jet, and the chemical energy release of PTFE-matrix reactive materials.

关键词： Reactive materials Shaped charge Reactive liner Jet formation Penetration behavior

Force chains based mesoscale simulation on the dynamic response of Al-PTFE granular composites

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Defence Technology（防务技术） 2021年第1期17卷 56-63页

作者： Le Tang Chao Ge Huan-guo Guo Qing-bo Yu Hai-fu Wang Beijing Institute of Technology China

Force chains based mesoscale simulation is conducted to investigate the response behavior of aluminumpolytetrafluoroethylene(Al-PTFE)granular composites under a low-velocity impact.A two-dimensional model followed the randomly normal distribution of real Al particles size is developed.The dynamic compressive process of Al-PTFE composites with varied Al mass fraction is simulated and validated against the experiments.The results indicate that,force chains behavior governed by the number and the size of agglomerated Al particles,significantly affects the impact response of the material.The failure mode of the material evolves from shear failure of matrix to debonding failure of particles with increasing density.A high crack area of the material is critical mechanism to arouse the initiation reaction.The damage maintained by force chains during large plastic strain builds up more local stresses concentration to enhance a possible reaction performance.In addition,simulation is performed with identical mass fraction but various Al size distribution to explore the effects of size centralization and dispersion on the mechanical properties of materials.It is found that smaller sized Al particle of composites are more preferred than its bulky material in ultimate strength.Increasing dispersed degree is facilitated to create stable force chains in samples with comparable particle number.The simulation studies provide further insights into the plastic deformation,failure mechanism,and possible energy release capacity for Al-PTFE composites,which is helpful for further design and application of reactive materials.

关键词： Al-PTFE Granular composites Mesoscale simulation Dynamic response Force chains

The Pd-catalyzed synthesis of difluoroethyl and difluorovinyl compounds with a chlorodifluoroethyl iodonium salt(CDFI)

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Chinese Chemical Letters 2022年第3期33卷 1541-1544页

作者： Yaru Niu Chengyao Kimmy Cao Chenxin ge Hongmei Qu chao Chen Key Laboratory of Systems Bioengineering Ministry of EducationDepartment of Pharmaceutical EngineeringSchool of Chemical Engineering and TechnologyTianjin UniversityTianjin 300350China Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology(Ministry of Education MOE)Department of ChemistryTsinghua UniversityBeijing 100084China State Key Laboratory of Elemento-Organic Chemistry Nankai UniversityTianjin 300071China

Herein, we report a simple and efficient method for the direct installation of chlorodifluoroethyl group onto aromatic molecules of various aromatic amides with a new 2-chloro,2,2-difluoroethyl(mesityl)iodonium salt(CDFI). Moreover, the chlorodifluoroethyl compounds could be smoothly converted into difluorovinyl compounds in a one-pot or discrete procedure and regarded as a steady source of difluorovinyl compounds with “HCl-mask”.

关键词： Iodonium salts C-H activation Pd-catalyzed Difluoroethylation Difluorovinylation