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Energy dissipation mechanism and ballistic characteristic optimization in foam sandwich panels against spherical projectile impact

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Defence technology（防务技术） 2024年第5期35卷 108-122页

作者： Jianqiang Deng Tao Liu Liming Chen Xin Pan Jingzhe Wang Shaowei Zhu Weiguo Li College of Aerospace Engineering Chongqing UniversityChongqing 400030China State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing UniversityChongqing 400030China chongqing Key Laboratory of Heterogeneous Material Mechanics Chongqing UniversityChongqing 400030China State Key Laboratory of Explosion science and technology Beijing Institute of TechnologyBeijing 100081China

This study systematically examines the energy dissipation mechanisms and ballistic characteristics of foam sandwich panels(FSP)under high-velocity impact using the explicit non-linear finite element *** on the geometric topology of the FSP system,three FSP configurations with the same areal density are derived,namely multi-layer,gradient core and asymmetric face sheet,and three key structural parameters are identified:core thickness(t_(c)),face sheet thickness(t_(f))and overlap face/core number(n_(o)).The ballistic performance of the FSP system is comprehensively evaluated in terms of the ballistic limit velocity(BLV),deformation modes,energy dissipation mechanism,and specific penetration energy(SPE).The results show that the FSP system exhibits a significant configuration dependence,whose ballistic performance ranking is:asymmetric face sheet>gradient core>*** mass distribution of the top and bottom face sheets plays a critical role in the ballistic resistance of the FSP *** BLV and SPE increase with tf,while the raising tcor noleads to an increase in BLV but a decrease in ***,a face-core synchronous enhancement mechanism is discovered by the energy dissipation analysis,based on which the ballistic optimization procedure is also conducted and a design chart is *** study shed light on the anti-penetration mechanism of the FSP system and might provide a theoretical basis for its engineering application.

关键词： Sandwich panel Numerical simulation Ballistic resistance Specific penetration energy Energy analysis

Continuous advantage learning for minimum-time trajectory planning of autonomous vehicles

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science China(Information sciences) 2024年第7期67卷 285-294页

作者： Zhuo LI Weiran WU Jialin WANG Gang WANG Jian SUN School of Automation Beijing Institute of Technology Beijing Institute of technology chongqing Innovation Center China academy of Launch Vehicle technology Intelligent Game and Decision Laboratory

This paper investigates the minimum-time trajectory planning problem of an autonomous vehicle. To deal with unknown and uncertain dynamics of the vehicle, the trajectory planning problem is modeled as a Markov decision process with a continuous action space. To solve it, we propose a continuous advantage learning(CAL) algorithm based on the advantage-value equation, and adopt a stochastic policy in the form of multivariate Gaussian distribution to encourage exploration. A shared actor-critic architecture is designed to simultaneously approximate the stochastic policy and the value function, which greatly reduces the computation burden compared to general actor-critic methods. Moreover, the shared actor-critic is updated with a loss function built as mean square consistency error of the advantage-value equation, and the update step is performed several times at each time step to improve data efficiency. Simulations validate the effectiveness of the proposed CAL algorithm and its better performance than the soft actor-critic algorithm.

关键词： trajectory planning continuous advantage learning stochastic policy shared actor-critic

Experimental investigation of spectral evolution in flash radiation by hypervelocity impact on aluminum plates

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Defence technology（防务技术） 2024年第7期37卷 96-110页

作者： Xing Chen Yonggang Lu Zhiwen Li Zhonghua Cui Institute of Systems Engineering China Academy of Engineering PhysicsMianyang 621900SichuanChina chongqing Qianwei technology Group Co. LtdChongqing 401121China

In this study,a series of hypervelocity impact tests were carried out based on a two-stage light gas gun,and the sequence spectrum and radiation evolution data of the impact products under different impact conditions were *** diameter of the projectile is 3-5 mm,the impact velocity is 3.13-6.58 km/s,and the chamber pressure is 0.56-990 *** spectrum of ejected debris cloud in the 250-310 nm band were obtained using a transient spectral measurement system and a multi-channel radiometer measurement *** test results reveal that the flash radiation intensity increases as a power function with the kinetic energy of the ***,the peak value of the line spectrum decreases as the chamber vacuum degree increases,while the radiation width gradually *** line spectrum in the spectral characterization curve corresponds to the ejected debris clouds splitting phase,which does not produce significant line spectrum during material fragmentation and is dominated by the continuum spectrum produced by blackbody *** will appear one or three characteristic peaks in the flash radiation time curve,the first and second peaks correspond to the penetration phase and the third peak corresponds to the expansion phase of the ejected debris clouds on the time scale,the first and second peaks are more sensitive to the chamber vacuum degree,and when the pressure is higher than 99 Pa,the first and second characteristic peaks will *** radiant heat attenuation of the flash under different impact conditions is significantly different,the attenuation exponent has a power function relationship with the impact velocity and the chamber vacuum degree,while the attenuation exponent has a linear relationship with the diameter of the projectile,the specific expression of the attenuation exponent is obtained by *** findings from this research can serve as a valuable reference for remote diagnostic technologies based on flash radiation characte

关键词： Hypervelocity impact Flash radiation Evolution Spectral characteristics Damage evaluation

Eureka lemon zinc finger protein ClDOF3.4 interacts with citrus yellow vein clearing virus coat protein to inhibit viral infection

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Journal of Integrative Agriculture 2024年第6期23卷 1979-1993页

作者： Ping Liao Ting Zeng Mengyang Huangfu Cairong Zheng Jiequn Ren Changyong Zhou Yan Zhou Integrative science Center of Germplasm Creation in Western China(chongqing)science City Citrus Research InstituteSouthwest UniversityChongqing 400712China National Citrus Engineering Research Center Citrus Research InstituteSouthwest UniversityChongqing 400712China chongqing Three Gorges academy of Agricultural science Chongqing Three Gorges UniversityChongqing 404020China

Citrus yellow vein clearing virus(CYVCV)is a new citrus virus that has become an important factor restricting the development of China’s citrus industry,and the CYVCV coat protein(CP)is associated with viral *** this study,the Eureka lemon zinc finger protein(ZFP)ClDOF3.4 was shown to interact with CYVCV CP in vivo and in *** expression of ClDOF3.4 in Eureka lemon induced the expression of salicylic acid(SA)-related and hypersensitive response marker genes,and triggered a reactive oxygen species burst,ion leakage necrosis,and the accumulation of free ***,the CYVCV titer in ClDOF3.4 transgenic Eureka lemon plants was approximately 69.4%that in control plants 6 mon after inoculation,with only mild leaf chlorotic spots observed in those transgenic *** together,the results indicate that ClDOF3.4 not only interacts with CP but also induces an immune response in Eureka lemon by inducing the SA *** is the first report that ZFP is involved in the immune response of a citrus viral disease,which provides a basis for further study of the molecular mechanism of CYVCV infection.

关键词： citrus yellow vein clearing virus coat protein ClDOF3.4 plant immune response

Broadband Dual-Input Doherty Power Amplifier Design Based on a Simple Adaptive Power Dividing Ratio Function

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China Communications 2024年第5期21卷 97-112页

作者： Dai Zhijiang Zhong Kang Li Mingyu Pang Jingzhou Jin Yi School of Microelectronics and Communication Engineering Chongqing UniversityChongqing 400044China Xi’an Branch of China academy of Space technology Xi’an 710100China

In this paper,a simple adaptive power dividing function for the design of a dual-input Doherty power amplifier(DPA)is *** the presented approaches,the signal separation function(SSF)at different frequency points can be characterized by a *** in the practical test,the coefficients of SSF can be determined by measuring a small number of data points of input *** as other dualinput DPAs,the proposed approach can also achieve high output power and back-off efficiency in a broadband operation band by adjusting the power distribution ratio ***,a 1.5-2.5 GHz highefficiency dual-input Doherty power amplifier is implemented according to this *** test results show that the peak power is 48.6-49.7d Bm,and the 6-d B back-off efficiency is 51.0-67.0%,and the saturation efficiency is 52.4-74.6%.The digital predistortion correction is carried out at the frequency points of 1.8/2.1GHz,and the adjacent channel power ratio is lower than-54.5d *** and experiment results can verify the effectiveness and correctness of the proposed method.

关键词： broadband doherty power amplifier dualinput efficiency enhancement load modulation

Layer-by-layer assembly of chitosan and carbon nanotube on cotton fabric for strain and temperature sensing

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Journal of Materials science & technology 2024年第6期173卷 114-120页

作者： Ye-Xin Zhang Yi-Dong Li An-Ke Du Yuanpeng Wu Jian-Bing Zeng chongqing Key Laboratory of Soft-Matter Material Chemistry and Function Manufacturing School of Chemistry and Chemical EngineeringSouthwest UniversityChongqing 400715China chongqing academy of science and technology Chongqing 401123China School of New Energy and Materials State Key Laboratory of Oil and Gas Reservoir Geology and ExploitationSouthwest Petroleum UniversityChengdu 610500China

Layer-by-layer(LBL)assembly shows great potential in fabrication of flexible conductive cotton fabrics(FCCF)with carbon nanotubes(CNT)as conductive components but is limited because complicated chemical modification of CNT is usually ***,we reported a facile and eco-friendly LBL approach to fabricating FCCF by dipping in chitosan(CS)aqueous solution and poly(sodium 4-styrenesulfonate)(PSS)wrapped CNT aqueous dispersion *** FCCF with electrical conductivity higher than 30 S/m was achieved when 4 layers of CNT were coated on the cotton fabric(CF).The obtained FCCF possessed outstanding mechanical stability with electrical resistivity almost unchanged after exposure to 500 times mechanical abrasion and 500 circles of tape *** FCCF showed excellent strain sensing performance with high sensitivity(with a gauge factor up to 35.1)and a fast response time(70 ms).It can be used as a strain sensor to accurately detect various human deformations such as finger bending and joint *** FCCF could be used as a temperature sensor in that it exhibited stable and reproducible negative temperature sensing behavior in the temperature range of 30-100℃.

关键词： Flexible conductive cotton fabric Layer-by-layer Temperature sensing Strain sensing

Amphipathic Janus Nanofibers Aerogel for Efficient Solar Steam Generation

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Energy & Environmental Materials 2024年第4期7卷 422-432页

作者： Rui Wang Jinshuo Deng Ping Wu Qianli Ma Xiangting Dong Wensheng Yu Guixia Liu Jinxian Wang Lei Liu chongqing Research Institute Changchun University of Science and Technology Key Laboratory of Applied Chemistry and Nanotechnology at Universities of Jilin Province Changchun University of Science and Technology

Solar steam generation is a promising water purification technology due to its low-cost and environmentally friendly applications in water purification and ***,hydrophilic or hydrophobic materials alone are insufficient in achieving necessary characteristics for constructing highquality solar steam generators with good comprehensive properties.

关键词： aerogels electrospinning photothermal materials solar desalination solar steam generation

Influence of Micro/Nano-Ti Particles on the Corrosion Behavior of AZ31-Ti Composites

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Acta Metallurgica Sinica(English Letters) 2024年第3期37卷 484-498页

作者： Jinchao Jiao Jin Zhang Yong Lian Shengli Han Kaihong Zheng Fusheng Pan Institute for Advanced Materials and technology University of Science and Technology BeijingBeijing 10083China Beijing Key Laboratory for Corrosion Erosion and Surface technology Beijing 100083China Institute of New Materials Guangdong Academy of SciencesGuangzhou 510650China National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 404100China

Adding Ti particles to magnesium alloy simultaneously enhances its strength and ***,how these particles influence on Mg alloy’s corrosion performance is seldom *** corrosion behavior of AZ31-Ti composites containing titanium nanoparticles(1.5 and 5 wt%)and micron particles(10 wt%)prepared by powder metallurgical in 3.5 wt%NaCl solution was *** results indicate that Ti particles serve as the primary location for the cathodic hydrogen reduction reaction,resulting in intense galvanic corrosion between the Ti and Mg *** nanoparticles distributed at the interface of the original AZ31 powder were in a discontinuous mesh structure,thus failing to act as a barrier against *** corrosion products with the existence of numerous cracks gradually peel off during the corrosion process and cannot protect the *** average corrosion rate P_(w) of AZ31,AZ31-1.5%Ti,AZ31-5%Ti,and AZ31-10%Ti after 7 days of immersion is 27.55,105.65,283.67,and 99.35 mm/y,***,AZ31-Ti composites can be considered as potential candidates for degradable fracturing ***,it is recommended to improve their corrosion resistance through surface treatment.

关键词： AZ31-Ti composite Nano-Ti Micro-Ti Corrosion behavior Scanning Kelvin probe force microscopy(SKPFM)

Estimation of cancer cell migration in biomimetic random/oriented collagen fiber microenvironments

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Chinese Physics B 2024年第5期33卷 749-756页

作者：姚静如李国强姚喜耀周连杰叶志凯刘艳平郑栋天唐婷宋克纳陈果刘雳宇 chongqing Key Laboratory of Soft Condensed Matter Physics and Smart Materials College of PhysicsChongqing UniversityChongqing 401331China chongqing Key Laboratory for Resource Utilization of Heavy Metal Wastewater Aquatic Ecosystems in the Three Gorges Reservoir Region of Chongqing Observation and Research StationChongqing University of Arts and SciencesYongchuan 402160China Wenzhou Institute University of Chinese Academy of SciencesWenzhou 325000China Department of Biomedical Engineering Chongqing University of Posts and TelecommunicationsChongqing 400065China College of Medical technology and Engineering Henan University of Science and TechnologyHenan 471023China

Increasing data indicate that cancer cell migration is regulated by extracellular matrixes and their surrounding biochemical microenvironment,playing a crucial role in pathological processes such as tumor invasion and ***,conventional two-dimensional cell culture and animal models have limitations in studying the influence of tumor microenvironment on cancer cell ***,the further development of microfluidic technology has provided solutions for the study of such *** utilize microfluidic chip to build a random collagen fiber microenvironment(RFM)model and an oriented collagen fiber microenvironment(OFM)model that resemble early stage and late stage breast cancer microenvironments,*** combining cell culture,biochemical concentration gradient construction,and microscopic imaging techniques,we investigate the impact of different collagen fiber biochemical microenvironments on the migration of breast cancer MDA-MB-231-RFP *** results show that MDA-MB-231-RFP cells migrate further in the OFM model compared to the RFM model,with significant differences ***,we establish concentration gradients of the anticancer drug paclitaxel in both the RFM and OFM models and find that paclitaxel significantly inhibits the migration of MDA-MB-231-RFP cells in the RFM model,with stronger inhibition on the high concentration side compared to the low concentration ***,the inhibitory effect of paclitaxel on the migration of MDA-MB-231-RFP cells in the OFM model is *** findings suggest that the oriented collagen fiber microenvironment resembling the late-stage tumor microenvironment is more favorable for cancer cell migration and that the effectiveness of anticancer drugs is *** RFM and OFM models constructed in this study not only provide a platform for studying the mechanism of cancer development,but also serve as a tool for the initial measurement of drug screening.

关键词： microfluidic chip random collagen fiber microenvironment(RFM) oriented collagen fiber microenvironment(OFM) cancer cell migration