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Analytical solution for the effective elastic properties of rocks with the tilted penny-shaped cracks in the transversely isotropic background

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Petroleum Science 2024年第1期21卷 221-243页

作者： zheng-Qian Ma Xing-Yao yin Zhao-Yun Zong Yuan-Yuan Tan Ya-Ming yang National Key Laboratory of Deep Oil and Gas China University of Petroleum(East China)Qingdao266580ShandongChina School of Geosciences China University of Petroleum(East China)Qingdao 266580ShandongChina Pilot National Laboratory for Marine Science and Technology(Qingdao) Qingdao266200ShandongChina

Seismic prediction of cracks is of great significance in many disciplines,for which the rock physics model is ***,up to now,multitudinous analytical models focus primarily on the cracked rock with the isotropic background,while the explicit model for the cracked rock with the anisotropic background is rarely investigated in spite of such case being often encountered in the ***,we first studied dependences of the crack opening displacement tensors on the crack dip angle in the coordinate systems formed by symmetry planes of the crack and the background anisotropy,respectively,by forty groups of numerical *** on the conclusion from the experiments,the analytical solution was derived for the effective elastic properties of the rock with the inclined penny-shaped cracks in the transversely isotropic ***,we comprehensively analyzed,according to the developed model,effects of the crack dip angle,background anisotropy,filling fluid and crack density on the effective elastic properties of the cracked *** analysis results indicate that the dip angle and background anisotropy can significantly either enhance or weaken the anisotropy degrees of the P-and SH-wave velocities,whereas they have relatively small effects on the SV-wave velocity ***,the filling fluid can increase the stiffness coefficients related to the compressional modulus by reducing crack compliance parameters,while its effects on shear coefficients depend on the crack dip *** increasing crack density reduces velocities of the dry rock,and decreasing rates of the velocities are affected by the crack dip *** comparing with exact numerical results and experimental data,it was demonstrated that the proposed model can achieve high-precision estimations of stiffness ***,the assumption of the weakly anisotropic background results in the consistency between the proposed model and Hudson's published theory for the or

关键词： Effective elastic property Tilted crack Transverse isotropy Analytical solution Crack opening displacement

Greedy Lattice Paths with General Weights

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Acta Mathematica Sinica,English Series 2024年第9期40卷 2213-2222页

作者： yin Shan CHANG An Qi zheng College of Mathematics Sichuan UniversityChengdu 610065P.R.China

Let{X_(v):v∈Z^(d)}be *** *** S(π)=Σ_(v∈π)X_(v)be the weight of a self-avoiding lattice pathπ.Let M_(n)=max{S(π):πhas length n and starts from the origin}.We are interested in the asymptotics of Mn as n→∞.This model is closely related to the first passage percolation when the weights{X_(v):v∈Z^(d)}are non-positive and it is closely related to the last passage percolation when the weights{X_(v):v∈Z^(d)}are *** general weights,this model could be viewed as an interpolation between first passage models and last passage ***,this model is also closely related to a variant of the position of right-most particles of branching random *** the two assumptions that∃α>0,E(X_(0)^(+))^(d)(log^(+)X_(0)^(+))^(d+α)0,E(X_(0)^(+))^(d)(log^(+)X_(0)^(+))^(d+α)<+∞and that E[(X_(0)^(−))^(4)]<+∞,we prove that M_(n)/n converges to the same constant M almost surely as n tends to infinity.

关键词： Last passage percolation first passage percolation greedy lattice path

KLF4 Inhibits the Activation of Human Hepatic Stellate Cell In Vitro

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Current Medical Science 2024年第3期44卷 512-518页

作者： Xing-yu yang Zhe CHEN Jun TAN yin-kai XUE Hai zheng Department of Emergency Surgery Union HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan430022China Department of Thoracic Surgery The First Affiliated Hospital of Xi’an Jiaotong UniversityXi’an710061China Department of Thoracic Surgery Union HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan430022China

Objective Hepatic stellate cells(HSCs)play a crucial role in liver ***-stage liver fibrosis is reversible and intimately associated with the state of ***-like factor 4(KLF4)plays a pivotal role in a wide array of physiological and pathological *** study aimed to investigate the effect of KLF4 on the proliferation,apoptosis and phenotype of quiescent HSCs Methods We designed a KLF4 lentiviral vector and a KLF4 siRNA lentiviral vector,to upregulate and silence KLF4 expression in human HSC LX-2 cells via *** proliferation was assessed using the CCK-8 *** cytometry was used to detect the cell cycle distribution and apoptosis *** blotting was used to determine the levels of some quiescence and activation markers of HSCs Results Overexpression of KLF4 significantly increased the levels of E-cadherin and ZO-1,which are quiescent HSC markers,while significantly decreased the levels of N-cadherin and a-SMA,known activated HSC *** contrast,cell proliferation and apoptosis rates were elevated in LX-2 cells in which KLF4 expression was silenced Conclusion KLF4 inhibits the proliferation and activation of human LX-2 *** might be a key regulatory protein in the maintenance of HSC quiescence and may serve as a target for the inhibition of hepatic fibrosis.

关键词： Kruppel-like factor 4 hepatic stellate cells LX-2 cells liver fibrosis

Unresolved Excess Accumulation of Myelin-Derived Cholesterol Contributes to Scar Formation after Spinal Cord Injury

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Research 2024年第1期2023卷 17-32页

作者： Bolin zheng Yijing He Shuai yin Xu Zhu Qing Zhao Huiyi yang Zhaojie wang Rongrong Zhu Liming Cheng Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration Ministry of EducationDepartment of OrthopedicsTongji HospitalSchool of MedicineTongji UniversityShanghai 200092China Frontier Science Center for Stem Cell Research School of Life Science and TechnologyTongji UniversityShanghai 200092China Clinical Center for Brain and Spinal Cord Research Tongji UniversityShanghai 200092China

Spinal cord injury triggers complex pathological cascades,resulting in destructive tissue damage and incomplete tissue *** formation is generally considered a barrier for regeneration in the central nervous ***,the intrinsic mechanism of scar formation after spinal cord injury has not been fully ***,we report that excess cholesterol accumulates in phagocytes and is inefficiently removed from spinal cord lesions in young adult ***,we observed that excessive cholesterol also accumulates in injured peripheral nerves but is subsequently removed by reverse ***,preventing reverse cholesterol transport leads to macrophage accumulation and fibrosis in injured peripheral ***,the neonatal mouse spinal cord lesions are devoid of myelin-derived lipids and can heal without excess cholesterol *** found that transplantation of myelin into neonatal lesions disrupts healing with excessive cholesterol accumulation,persistent macrophage activation,and *** internalization suppresses macrophage apoptosis mediated by CD5L expression,indicating that myelin-derived cholesterol plays a critical role in impaired wound *** together,our data suggest that the central nervous system lacks an efficient approach for cholesterol clearance,resulting in excessive accumulation of myelin-derived cholesterol,thereby inducing scar formation after injury.

关键词： healing Spinal impaired

Convolution-Transformer for Image Feature Extraction

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Computer Modeling in Engineering & Sciences 2024年第10期141卷 87-106页

作者： Lirong yin Lei Wang Siyu Lu Ruiyang Wang Youshuai yang Bo yang Shan Liu Ahmed AlSanad Salman A.AlQahtani zhengtong yin Xiaolu Li Xiaobing Chen Wenfeng zheng Department of Geography and Anthropology Louisiana State UniversityBaton RougeLA70803USA School of Automation University of Electronic Science and Technology of ChinaChengdu610054China College of Computer and Information Sciences King Saud UniversityRiyadh11574Saudi Arabia College of Resources and Environmental Engineering Key Laboratory of Karst Georesources and Environment(Guizhou University)Ministry of EducationGuiyang550025China School of Geographical Sciences Southwest UniversityChongqing400715China School of Electrical and Computer Engineering Louisiana State UniversityBaton RougeLA70803USA

This study addresses the limitations of Transformer models in image feature extraction,particularly their lack of inductive bias for visual *** to Convolutional Neural Networks(CNNs),the Transformers are more sensitive to different hyperparameters of optimizers,which leads to a lack of stability and slow *** tackle these challenges,we propose the Convolution-based Efficient Transformer Image Feature Extraction Network(CEFormer)as an enhancement of the Transformer *** model incorporates E-Attention,depthwise separable convolution,and dilated convolution to introduce crucial inductive biases,such as translation invariance,locality,and scale invariance,into the Transformer ***,we implement a lightweight convolution module to process the input images,resulting in faster convergence and improved *** results in an efficient convolution combined Transformer image feature extraction *** results on the ImageNet1k Top-1 dataset demonstrate that the proposed network achieves better accuracy while maintaining high computational *** achieves up to 85.0%accuracy across various model sizes on image classification,outperforming various baseline *** integrated into the Mask Region-ConvolutionalNeuralNetwork(R-CNN)framework as a backbone network,CEFormer outperforms other models and achieves the highest mean Average Precision(mAP)*** research presents a significant advancement in Transformer-based image feature extraction,balancing performance and computational efficiency.

关键词： Transformer E-Attention depth convolution dilated convolution CEFormer

The Short-Duration Heavy Rainfall in Different Quadrants of Northeast China Cold Vortices

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Journal of Meteorological Research 2024年第2期38卷 321-338页

作者： Lei yang Yongguang zheng Liaoning Meteorological Disaster Monitoring and Early Warning Center Shenyang 110166 National Meteorological Centre China Meteorological AdministrationBeijing 100081 China Meteorological Administration Tornado Key Laboratory Foshan 528315

The Northeast China cold vortex(NCCV)is one of the main synoptic-scale systems causing short-duration heavy rainfall(SDHR)in Northeast *** conditions(e.g.,water vapor,instability,and vertical wind shear)are known to be distinctly different over the four quadrants of NCCVs,rendering prediction of the SDHR related to NCCVs(NCCV_SDHR)more *** on 5-yr hourly rainfall observations from 3196 automatic weather stations and ERA5 reanalysis data,10,232 NCCV_SDHR events were identified and divided into four quadrant groups according to their relative position to the center of the NCCV(CVC).The results show that the southeast quadrant features the highest frequency of SDHR,with stronger intensity,longer duration,and wider coverage;and the SDHR in different quadrants presents different formation mechanisms and varied temporal evolution.A new coordinate system is established relative to the CVC that uses the CVC as the origin and the radius of the NCCV(r CV)as the unit *** this new coordinate system,all of the NCCV_SDHR events in the 5-yr study period are *** is found that the occurrence frequency of NCCV_SDHR initially increases and then decreases with increasing distance from the *** highest frequency occurs mainly between 0.8 and 2.5 times r CV from the CVC in the southeast *** can be attributed to the favorable conditions,such as convergence of the low-level shear line and abundant water vapor,which are concentrated in this ***,high-frequency NCCV_SDHR larger than 50 mm(NCCV_SDHR50)is observed to be closer to the *** NCCV_SDHR50occurs,the NCCV is in closer proximity to the subtropical high,resulting in stronger low-level convergence and more abundant water ***,there are lower lifting condensation levels and stronger 0-6-and 0-1-km vertical wind shears in these *** findings provide a valuable reference for more accurate prediction of NCCV_SDHR.

关键词： Northeast China cold vortex short-duration heavy rainfall statistical characteristics environmental conditions

Preliminary discussion on the ignition mechanism of exploding foil initiators igniting boron potassium nitrate

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Defence Technology（防务技术） 2024年第2期32卷 222-231页

作者： Haotian Jian Guoqiang zheng Lejian Chen zheng Ning Guofu yin Peng Zhu Ruiqi Shen School of Chemistry and Chemical Engineering Nanjing University of Science and TechnologyNanjing 210094China Micro-Nano Energetic Devices Key Laboratory of MIIT Nanjing University of Science and TechnologyNanjing 210094China Anhui Province Key Laboratory of Microsystem the 43rd Research Institute of CETCHefei 230088China Science and Technology on Applied Physical and Chemistry Laboratory Shanxi Applied Physics and Chemistry Research Institute Xi'an 710061China

Exploding foil initiator(EFI)is a kind of advanced device for initiating explosives,but its function is unstable when it comes to directly igniting *** solve the problem,this research aims to reveal the ignition mechanism of EFIs directly igniting *** oscilloscope,a photon Doppler velocimetry,and a plasma spectrum measurement system were employed to obtain information of electric characteristics,impact pressure,and plasma *** results of the electric characteristics and the impact pressure were inconsistent with ignition *** only thing that the ignition success tests had in common was that their plasma all had a relatively long period of high-temperature duration(HTD).It eventually concludes that the ignition mechanism in this research is the microconvection heat transfer rather than the shock initiation,which differs from that of exploding foil initiators detonating ***,the methods for evaluating the ignition success of semiconductor bridge initiators are not entirely applicable to the tests mentioned in this *** HTD is the critical parameter for judging the ignition success,and it is influenced by two factors:the late time discharge and the energy of the electric *** longer time of the late time discharge and the more energy of the electric explosion,the easier it is to expand the HTD,which improves the probability of the ignition success.

关键词： Exploding foil initiator PDV Plasma spectrum Ignition mechanism Boron potassium nitrate

Quantum key distribution over a mimicked dynamic-scattering channel

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Science China(Information Sciences) 2024年第4期67卷 323-330页

作者： Qi-Hang LU Fang-Xiang WANG Wei CHEN Hai-yang FU yin-Jie LU Shuang WANG De-Yong HE Zhen-Qiang yin Guang-Can GUO zheng-Fu HAN CAS Key Laboratory of Quantum Information University of Science and Technology of China CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of China Hefei National Laboratory University of Science and Technology of China

Free-space quantum key distribution(QKD) plays an important role in the global quantum network. However, free space channels suffer from the atmospheric turbulence and scattering effects of haze,fog, and dust, which significantly weaken the performance of QKD or even block the secure quantum ***, we prove the performance of QKD over a dynamic scattering channel can be enhanced significantly using a fast wavefront shaping technique. The system achieves on average 10-dB enhancement of quantum transmission efficiency and establishes a secure quantum link for QKD. Our work demonstrates the feasibility of QKD through free-space dynamic scattering channels and enhances the deployment capability of complex-channel QKD system.

关键词： quantum key distribution free space channel channel turbulence channel scattering wavefront shaping

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Effect of solvent on the initiation mechanism of living anionic polymerization of styrene:A computational study

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Chinese Journal of Chemical Engineering 2024年第5期69卷 135-142页

作者： Shen Li yin-Ning Zhou Zhong-Xin Liu zheng-Hong Luo School of Chemical Engineering and Technology Hainan UniversityHaikou 570228China Department of Chemical Engineering School of Chemistry and Chemical EngineeringState Key Laboratory of Metal Matrix CompositesShanghai Jiao Tong UniversityShanghai 200240China

For living anionic polymerization(LAP),solvent has a great influence on both reaction mechanism and *** this work,by using the classical butyl lithium-styrene polymerization as a model system,the effect of solvent on the mechanism and kinetics of LAP was revealed through a strategy combining density functional theory(DFT)calculations and kinetic *** terms of mechanism,it is found that the stronger the solvent polarity,the more electrons transfer from initiator to solvent through detailed energy decomposition analysis of electrostatic interactions between initiator and solvent ***,we also found that the stronger the solvent polarity,the higher the monomer initiation energy barrier and the smaller the initiation rate ***,initiation is more favorable at lower temperatures based on the calculated results ofΔG_(TS).Finally,the kinetic characteristics in different solvents were further examined by kinetic *** is found that in benzene and n-pentane,the polymerization rate exhibits first-order ***,slow initiation and fast propagation were observed in tetrahydrofuran(THF)due to the slow free ion formation rate,leading to a deviation from first-order kinetics.

关键词： Living anionic polymerization Solvent effect Reaction kinetics Computational chemistry Mathematical modeling Kinetic modeling