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Dynamic compressive response of porcine muscle measured using a split Hopkinson bar system with a pair of PVDF force transducers

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Defence Technology（防务技术） 2023年第10期28卷 298-305页

作者： Yao-ke Wen Liang Xu Ai-jun Chen fang-dong dong Bin Qin School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing210094China School of Science Nanjing University of Science and TechnologyNanjing210094China Science and Technology on Transient Impact Laboratory Beijing102202China

The classic metallic Split Hopkinson Pressure Bar(SHPB)cannot capture the transmitted signal accurately when measuring soft biological tissue,because of the very low wave impedance and strength of this *** the dynamic compressive response of porcine muscle has been investigated by using a modified *** forces on both ends of the sample measured using Polyvinylidene fluor(PVDF)transducers were applied to calculate the stress in the specimen instead of the strain gauge signal on the transmitted ***,a circular cardboard disk pulse shaper was applied for generating a suitable incident pulse to achieve stress equilibrium and constant strain rates in the ***,the dynamic mechanical properties of porcine muscle parallel and perpendicular to the fiber directions were measured,and the stress equilibrium process during loading was analyzed,as well as the inertia-induced extra stress being ***,quasi-static tests were conducted at two different strain rates to investigate the strain rate dependence using a universal material testing *** results show that the stress-strain curves are sensitive to strain rate in the two different loading *** compressive stress perpendicular to the fiber direction is stiffer than that parallel to the fiber *** addition,a strain rate-dependent constitutive model was developed based on the mechanical response of the muscle at different strain rates and fitted to the experimental *** results show that the overall fit is good,and the constitutive model could describe the muscle's dynamic mechanical properties.

关键词： PVDF Hopkinson bar Porcine muscle Dynamic mechanical properties Constitutive model

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Effects of Scale-Free Topological Properties on Dynamical Synchronization and Control in Coupled Map Lattices

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Communications in Theoretical Physics 2007年第2期47卷 361-368页

作者： CHEN Wei fang Jin-Qing kang Ge-Wen School of Automation Engineering University of Electronic Science and Technology of China Chengdu 610054 China China Institute of Atomic Energy P.O. Box 275-81 Beijing 102413 China

In the paper, we study effects of scale-free （SF） topology on dynamical synchronization and control in coupled map lattices （CIVIL）. Our strategy is to apply three feedback control methods, including constant feedback and two types of time-delayed feedback, to a small fraction of network nodes to reach desired synchronous state. Two controlled bifurcation diagrams verses feedback strength are obtained respectively. It is found that the value of critical feedback strength γc for the first time-delayed feedback control is increased linearly as e is increased linearly. The GML with SF loses synchronization and intermittency occurs if γ 〉 γc. Numerical examples are presented to demonstrate all results.

关键词： scale-free network coupled map lattice dynamical synchronization feedback control timedelayed feedback

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Relationship between the Virtual Dynamic Thinning Line and the Self-Thinning Boundary Line in Simulated Plant Populations

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Journal of Integrative Plant Biology 2008年第3期50卷 280-290页

作者： kang Chen Hong-Mei kang Juan Bai Xiang-Wen fang Gang Wang Key Laboratory of And and Grassland Ecology Lanzhou University Ministry of Education Lanzhou 730000 China

The self-thinning rule defines a straight upper boundary line on log-log scales for all possible combinations of mean individual biomass and density in plant populations. Recently, the traditional slope of the upper boundary line, -3/2, has been challenged by -4/3 which is deduced from some new mechanical theories, like the metabolic theory. More experimental or field studies should be carried out to identify the more accurate self-thinning exponent. But it＇s hard to obtain the accurate self-thinning exponent by fitting to data points directly because of the intrinsic problem of subjectivity in data selection. The virtual dynamic thinning line is derived from the competition-density （C-D） effect as the initial density tends to be positive infinity, avoiding the data selection process. The purpose of this study was to study the relationship between the virtual dynamic thinning line and the upper boundary line in simulated plant stands. Our research showed that the upper boundary line and the virtual dynamic thinning line were both straight lines on log-log scales. The slopes were almost the same value with only a very little difference of 0.059, and the intercept of the upper boundary line was a little larger than that of the virtual dynamic thinning line. As initial size and spatial distribution patterns became more uniform, the virtual dynamic thinning line was more similar to the upper boundary line. This implies that, given appropriate parameters, the virtual dynamic thinning line may be used as the upper boundary line in simulated plant stands.

关键词： area of suppression competition-density effect individual-based models self-thinning virtual dynamic thinning line

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Evidence for two types of Aquilegia ecalcarata and its implications for adaptation to new environments

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Plant Diversity 2022年第2期44卷 153-162页

作者： Lei Huang fang-dong Geng Jing-Jing Fan Wei Zhai Cheng Xue Xiao-Hui Zhang Yi Ren Ju-Qing kang National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest China College of Life SciencesShaanxi Normal UniversityXi'anShaanxi 710119China

Spurs have played an important role in the radiation of the genus Aquilegia,but little is known about how the spurless state arose in *** we aim to characterize the genetic divergence within *** and gain insights into the origin of this species.A total of 19 populations from *** and 23 populations from three of its closest relatives(Aquilegia kansuensis,Aquilegia rockii and Aquilegia yabeana)were sampled in this *** sequenced fifteen nuclear gene fragments across the genome and three chloroplast loci to conduct phylogenetic,PCoA and STRUCTURE *** analyses indicate that *** may not be monophyletic and can be divided into two distinct lineages(***Ⅰand ***Ⅱ).***Ⅰis genetically close to ***,whereas ***Ⅱis close to ***-with-migration analysis suggested that historical gene flow was low between ***Ⅰand ***,as well as between ***Ⅱand *** two distinct lineages of *** show significant divergence in 13 floral traits and also have distinct *** addition,both ***ⅠandⅡare adapted to a stony environment that differs from that of their closest relatives,indicating a habitat shift may have driven new *** findings enrich the understanding of how floral evolution contributes to species diversification.

关键词： Aquilegia ecalcarata Phylogeny Population structure Gene flow Spur loss

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FPGA implementation of neural network accelerator for pulse information extraction in high energy physics

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Nuclear Science and Techniques 2020年第5期31卷 27-35页

作者： Jun-Ling Chen Peng-Cheng Ai dong Wang Hui Wang Ni fang De-Li Xu Qi Gong Yuan-kang Yang Central China Normal University Wuhan 430079China

Extracting the amplitude and time information from the shaped pulse is an important step in nuclear physics *** this purpose,a neural network can be an alternative in off-line data *** processing the data in real time and reducing the off-line data storage required in a trigger event,we designed a customized neural network accelerator on a field programmable gate array platform to implement specific layers in a convolutional neural *** latter is then used in the front-end electronics of the *** fully reconfigurable hardware,a tested neural network structure was used for accurate timing of shaped pulses common in front-end *** design can handle up to four channels of pulse signals at *** peak performance of each channel is 1.665 Giga operations per second at a working frequency of 25 MHz.

关键词： Convolutional neural networks Pulse shaping Acceleration Front-end electronics

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Early Cretaceous Paleoclimate Characteristics of China:Clues from Continental Climate-indicative Sediments

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Acta Geologica Sinica(English Edition) 2015年第4期89卷 1307-1318页

作者： XIANG fang ZHANG Deyan CHEN kang FENG Qin Institute of Sedimentary Geology Chengdu University of Technology

The Cretaceous was one of the most remarkable ＇greenhouse＇ climate periods in geological history. Most of the reported studies of the Cretaceous paleoclimate are based upon marine sedimentary records. Large spatial scale paleoclimatic reconstruction, which has a higher time resolution based upon continental sediments in China, is rarely found. This study presents paleoclimate reconstruction for the six time periods of the Early Cretaceous in China by employing continental climate-indicative sediments, including calcareous deposits, coal, oil shale, gypsum, halite, desert sedimentary systems, ferruginous deposits and laterite, copper-bearing deposits, limestone and dolomite. Based on the distribution of the association of climate-indicative sediments and the influences of paleotopography and orogenic belts （or important structural belts） on climate, seven climatic zones have been identified： 1） a warm and humid zone; 2） a warm and humid-warm and arid zone; 3） a warm and arid zone; 4） an arid and hot zone; 5） the Tibet hot and humid zone; 6） a hot and arid-semiarid zone; and 7） a hot and humid-hot and arid one. It is found that the Early Cretaceous climatic zones of China were nearly latitudinally distributed from northwest to southeast. The arid- hot climatic zone expanded in the Aptian, suggesting that a hotter and drier climate prevailed in later period of the Early Cretaceous. Conversely, the humid climatic zone expanded in the Albian, indicating that a wetter climate appeared at the end of the Early Cretaceous. The overall distribution pattern of the seven climatic zones indicates that a hot-warm and arid climate was predominant in China; this coincides with a global ＇greenhouse climate＇ background. However, palaeogeographic features and specific geologic events, such as the existence and disappearance of the eastern high plateau, and the uplift and denudation of Yinshan, Yanshan, Tianshan, Qinling and Dabie Mountains, led to distinctive regional climatic feature

关键词： Early Cretaceous paleoclimate continental climate-indicative sediments climatic zone

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Magnetic properties of sputtered anisotropic Pr–Fe–B thin films with different structures and antiferromagnetic materials

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Rare Metals 2016年第12期35卷 926-929页

作者： fang Yang Wei Liu Zhi-dong Zhang Shenyang National Laboratory for Materials Science Institute of Metal Research and International Centre for Materials PhysicsChinese Academy of Sciences Superconducting Materials Research Center Northwest Institute for Nonferrous Metal Research

Anisotropic Pr-Fe-B films with soft-magnetic layer （Fe） and/or antiferromagnetic layer （Mn, FeMn or MnO） were prepared by direct-current （DC） magnetron sputtering on Si （100） substrates heated at 650℃. The influence of four types＇ different structures on the magnetic properties of Pr-Fe-B films was investigated. The phase and magnetic properties were characterized by means of X-ray diffraction （XRD） and superconducting quantum interference device （SQUID）. Addition of anti-ferromagnetic layer enhances both the coercivity and the remanence ratios of Pr-Fe-B films with suitable structures. The interface number increases and the antiferromagnetic-ferromagnetic exchange interaction is likely to become stronger, which affect the improvement of magnetic properties. To further understand the influence of structures with soft-magnetic Fe layer and/or antifer- romagnetic FeMn layer on the magnetic properties of Pr-Fe-B hard-magnetic films, the thickness of Pr-Fe-B layer was designed to decrease from 600 to 50 nm. The improvement of magnetic properties becomes obvious in Mo（50 nm）/Pr-Fe-B（25 nm）Mo（2 nm）FeMn（20 nm）Mo （2 nm）Pr-Fe-B（25 nm）/Mo（50 rim） film.

关键词： Magnetic materials Thin films Coercivity Hysteresis loop Sputtering

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Deep imitation reinforcement learning for self-driving by vision

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CAAI Transactions on Intelligence Technology 2021年第4期6卷 493-503页

作者： Qijie Zou kang Xiong Qiang fang Bohan Jiang College of Iatelligence Science and Technology National University of Defense TechnologyChangshaChina Infortmation Engineering Faculty Dalian UniversityDalianChina

Deep reinforcement learning has achieved some remarkable results in *** is quite a lot of work to do in the area of autonomous driving with high real-time requirements because of the inefficiency of reinforcement learning in exploring large continuous motion spaces.A deep imitation reinforcement learning(DIRL)framework is presented to leam control policies of self-driving vehicles,which is based on a deep deterministic policy gradient algorithm(DDPG)by *** DIRL framework comprises two components,the perception module and the conttol module,using imitation learning(IL)and DDPG,respectively;The perception module employs the IL network as an encoder which processes an image into a low-dimensional feature *** vector is then delivered to the control module which outputs control ***,the actor network of the DDPG is initialized with the trained IL network to improve exploration *** addition,a reward function for reinforcement learning is defined to improve the stability of self-driving vehicles,especially on *** is verified by the open racing car simulator(TORCS),and the results show that the correct control strategy is learned successfully and has less training time.

关键词： driving Deep network

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A fast and reliable overset unstructured grids approach

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Acta Mechanica Sinica 2013年第2期29卷 149-157页

作者： Zhong-Liang kang Chao Yan Jian Yu Yuan-Yuan fang Institute of Fluid Mechanics Beihang University Academy of Beijing Gas GroupCo. Ltd

A cell-centred overset unstructured grids approach is *** this approach,the intergrid boundary is initially established based on the wall distance from the cell centre,and is then *** accelerate the intergrid-boundary definition much more,a neighbor-toneighbor donor search algorithm based on advancing-front method is modified with the help of minimum cuboid *** simplify the communications between different grid cell types and to obtain second-order spatial accuracy,a new interpolation method is constructed based on linear reconstruction,which employs only one layer of fringe cells along the intergrid *** unsteady flows with relative motion,the intergrid boundary can be redefined fast and *** numerical results show that the present dynamic overset unstructured grids approach is accurate and reliable.

关键词： Overset unstructured grids·Dynamic grids·Intergrid-boundary definition·Interpolation

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Science Letters:A synthetic Toll-like receptor 2 ligand decreases allergic immune responses in a mouse rhinitis model sensitized to mite allergen

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2008年第4期9卷 279-285页

作者： Cheng ZHOU Xiao-dong kang Zhi CHEN Institute of Infectious Diseases the First Affiliated Hospital School of Medicine Zhejiang University Hangzhou 310003 China Experimental Animal Center School of Medicine Hangzhou Teacher＇s College Hangzhou 310018 China

It has been proposed that activation of Toll-like receptors （TLRs） plays crucial roles in the polarization of adaptive immune responses. A synthetic Toll-like receptor 2 （TLR2） ligand, Pam3CSK4, has been reported to modulate the balance of Th1/Th2 responses. We evaluated the modulation effect of Pam3CSK4 on allergic immune response in a mouse rhinitis model sensitized to house dust mite allergen （HDM）. Mice were sensitized and challenged with Dermatophagoidesfarinae allergen （Der f）, and then the allergic mice were treated by Pam3CSK4. Nasal allergic symptoms and eosinophils were scored. Der f-specific cytokine responses were examined in the splenocytes and bronchoalveolar lavage fluid （BALF）. Serum level of total IgE was also detected. After establishing a mouse allergic rhinitis model with HDM, we have showed that Pam3CSK4 treatment not only ameliorated the nasal allergic symptoms remarkably but also decreased the eosinophils and total inflammation cells in BALF significantly. Analysis of cytokine profile found that IFN-7 released from either BALF or stimulated splenocytes increased markedly in Pam3CSK4-treated mice, while IL-13 decreased significantly. Moreover, serum level of total IgE was significantly lower in Pam3CSK4-treated mice than in the untreated. Thus, in an allergic rhinitis mouse model developed with HDM, Pam3CSK4 was shown to exhibit an antiallergic effect, indicating its potential application in allergic diseases.

关键词： Toll-like receptor 2 (TLR2) Ligand Allergic immune response Mite allergen

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