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Nonlinear constitutive models of rock structural plane and their applications

Journal of Rock Mechanics and geotechnical Engineering 2024年第3期16卷 790-806页

作者： Wenlin Feng Shuangjian Niu Chunsheng qiao Dujian Zou School of Civil and Environmental Engineering Harbin Institute of TechnologyShenzhenChina Shenzhen Municipal Engineering Corporation Shenzhen518000China School of Civil Engineering Beijing Jiaotong UniversityBeijing100044China

Structural planes play an important role in controlling the stability of rock engineering,and the influence of structural planes should be considered in the design and construction process of rock *** this paper,mechanical properties,constitutive theory,and numerical application of structural plane are studied by a combination method of laboratory tests,theoretical derivation,and program *** test results reveal the change laws of various mechanical parameters under different roughness and normal *** the pre-peak stage,a non-stationary model of shear stiffness is established,and threedimensional empirical prediction models for initial shear stiffness and residual stage roughness are *** nonlinear constitutive models are established based on elasto-plastic mechanics,and the algorithms of the models are developed based on the return mapping *** to a large number of statistical analysis results,empirical prediction models are proposed for model parameters expressed by structural plane characteristic ***,the discrete element method(DEM)is chosen to embed the constitutive models for practical *** running programs of the constitutive models have been compiled into the discrete element model *** comparison results between the proposed model and the Mohr-Coulomb slip model show that the proposed model can better describe nonlinear changes at different stages,and the predicted shear strength,peak strain and shear stiffness are closer to the test *** research results of the paper are conducive to the accurate evaluation of structural plane in rock engineering.

关键词： Structural plane Engineering stability Roughness Normal stress Elasto-plastic constitutive model Discrete element method

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Mutations in the SARS-CoV-2 spike receptor binding domain and their delicate balance between ACE2 affinity and antibody evasion

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Protein & Cell 2024年第6期15卷 403-418页

作者： Song Xue Yuru Han Fan Wu qiao Wang Key Laboratory of Medical Molecular Virology (MOE/NHC/CAMS) Shanghai Institute of Infectious Disease and BiosecurityShanghai Frontiers Science Center of Pathogenic Microorganisms and InfectionSchool of Basic Medical SciencesShanghai Medical CollegeFudan UniversityShanghai 200032China

Intensive selection pressure constrains the evolutionary trajectory of SARS-CoV-2 genomes and results in various novel variants with distinct mutation *** mutations,particularly those within the receptor binding domain(RBD)of SARS-CoV-2 spike(S)protein,lead to the functional alteration in both receptor engagement and monoclonal antibody(mAb)***,we review the data of the RBD point mutations possessed by major SARS-CoV-2 variants and discuss their individual effects on ACE2 affinity and immune *** single amino acid substitutions within RBD epitopes crucial for the antibody evasion capacity may conversely weaken ACE2 binding ***,this weakened effect could be largely compensated by specific epistatic mutations,such as N501Y,thus maintaining the overall ACE2 affinity for the spike protein of all major *** predominant direction of SARS-CoV-2 evolution lies neither in promoting ACE2 affinity nor evading mAb neutralization but in maintaining a delicate balance between these two ***,this review interprets how RBD mutations efficiently resist antibody neutralization and meanwhile how the affinity between ACE2 and spike protein is maintained,emphasizing the significance of comprehensive assessment of spike mutations.

关键词： ACE2 affinity maintained

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The competition between Bidens pilosa and Setaria viridis alters soil microbial composition and soil ecological function

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Journal of Integrative Agriculture 2024年第1期23卷 267-282页

作者： qiao Li Jianying guo Han Zhang Mengxin Zhao State Key Laboratory for Biology of Plant Diseases and Insect Pests Institute of Plant ProtectionChinese Academy of Agricultural SciencesBeijing 100193China College of Life Science Yangtze UniversityJingzhou 434025China

Bidens pilosa is recognized as one of the major invasive plants in *** invasion has been associated with significant losses in agriculture,forestry,husbandry,and *** ecosystems play an important role in alien plant *** within the soil act as intermediaries between plants and soil ecological functions,playing a role in regulating soil enzyme activities and nutrient *** the interactions between invasive plants,soil microorganisms,and soil ecological processes is vital for managing and mitigating the impacts of invasive species on the *** this study,we conducted a systematic analysis focusing on *** and Setaria viridis,a common native companion plant in the invaded *** simulate the invasion process of ***,we constructed homogeneous plots consisting of *** and *** grown separately as monocultures,as well as in *** rhizosphere and bulk soils were collected from the alien plant *** and the native plant *** order to focus on the soil ecological functional mechanisms that contribute to the successful invasion of ***,we analyzed the effects of *** on the composition of soil microbial communities and soil ecological *** results showed that the biomass of *** increased by 27.51% and that of *** was significantly reduced by 66.56%.The organic matter contents in the bulk and rhizosphere soils of *** were approximately 1.30 times those in the native plant *** TN and NO_(3)^(-)contents in the rhizosphere soil of *** were 1.30 to 2.71 times those in the native plant *** activities of acid phosphatase,alkaline phosphatase,and urease in the rhizosphere soil of *** were 1.98-2.25 times higher than in the native plant *** high-throughput sequencing of the16S rRNA gene,we found that *** altered the composition of the soil microbial ***,many genera in Actinobacteria and Proteobacteri

关键词： plant invasion Bidens pilosa soil microbial composition soil properties soil enzyme activities

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Review of Three-phase Soft Switching Inverters and Challenges for Motor Drives

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CES Transactions on Electrical Machines and Systems 2024年第2期8卷 177-190页

作者： Haifeng Lu qiao Wang Jianyun Chai Yongdong Li IEEE the Department of Electrical Engineering Tsinghua UniversityBeijing 100084China the School of Electrical Engineering Xinjiang UniversityUrumqi 830047China

For electric vehicles (EVs),it is necessary to improve endurance mileage by improving the *** exists a trend towards increasing the system voltage and switching frequency,contributing to improve charging speed and power ***,this trend poses significant challenges for high-voltage and high-frequency motor controllers,which are plagued by increased switching losses and pronounced switching oscillations as consequences of hard *** deployment of soft switching technology presents a viable solution to mitigate these *** paper reviews the applications of soft switching technologies for three-phase inverters and classifies them based on distinct *** each type of inverter,the advantages and disadvantages are ***,the paper introduces the research progress and control methods of soft switching inverters (SSIs).Moreover,it presents a comparative analysis among the conventional hard switching inverters (HSIs),an active clamping resonant DC link inverter (ACRDCLI) and an auxiliary resonant commuted pole inverter (ARCPI).Finally,the problems and prospects of soft switching technology applied to motor controllers for EVs are put forward.

关键词： Soft switching inverters Zero-voltage switching Electric vehicles Motor drives

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A whole process damage constitutive model for layered sandstone under uniaxial compression based on Logistic function

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Journal of Central South University 2024年第7期31卷 2411-2430页

作者： LIU Dong-qiao gUO yun-peng LINg Kai LI Jie-yu State Key Laboratory for geomechanics and Deep Underground Engineering China University of Mining and Technology-BeijingBeijing 100083China School of Mechanics and Civil Engineering China University of Mining and Technology-BeijingBeijing 100083China

Bedding structural planes significantly influence the mechanical properties and stability of engineering rock *** study conducts uniaxial compression tests on layered sandstone with various bedding angles(0°,15°,30°,45°,60°,75°and 90°)to explore the impact of bedding angle on the deformational mechanical response,failure mode,and damage evolution processes of *** develops a damage model based on the Logistic equation derived from the modulus’s degradation considering the combined effect of the sandstone bedding dip angle and *** model is employed to study the damage accumulation state and its evolution within the layered rock *** research also introduces a piecewise constitutive model that considers the initial compaction characteristics to simulate the whole deformation process of layered sandstone under uniaxial *** results revealed that as the bedding angle increases from 0°to 90°,the uniaxial compressive strength and elastic modulus of layered sandstone significantly decrease,slightly increase,and then decline *** corresponding failure modes transition from splitting tensile failure to slipping shear failure and back to splitting tensile *** indicated by the modulus’s degradation,the damage characteristics can be categorized into four stages:initial no damage,damage initiation,damage acceleration,and damage deceleration *** theoretical damage model based on the Logistic equation effectively simulates and predicts the entire damage evolution ***,the theoretical constitutive model curves closely align with the actual stress−strain curves of layered sandstone under uniaxial *** introduced constitutive model is concise,with fewer parameters,a straightforward parameter determination process,and a clear physical *** study offers valuable insights into the theory of layered rock mechanics and holds implications for ensuring the safety of rock engineering.

关键词： layered sandstone uniaxial compression damage evolution Logistic function constitutive model

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Cooperative Covert Communication in Multi-Antenna Broadcast Channels

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China Communications 2024年第6期21卷 246-260页

作者： qiao Sen Liu guangjie Ji Xiaopeng Liu Weiwei School of Electrical and Information Engineering Nanjing University of Information Science and TechnologyNanjing 210044China School of Automation Nanjing University of Science and TechnologyNanjing 210094China

With the gradual popularization of 5g communications,the application of multi-antenna broadcasting technology has become ***,this study aims to investigate the wireless covert communication in the two-user cooperative multi-antenna broadcast *** focus on the issue that the deteriorated reliability and undetectability are mainly affected by the transmission *** tackle this issue,we design a scheme based on beamforming to increase the reliability and undetectability of wireless covert communication in the multi-antenna broadcast *** first modeled and analyzed the cooperative multi-antenna broadcasting system,and put forward the target *** we use the SCA(successive convex approximation)algorithm to transform the target problem into a series of convex *** the convex problems are solved and the covert channel capacity is *** order to verify the effectiveness of the scheme,we conducted simulation *** simulation results show that the proposed beamforming scheme can effectively improve the reliability and undetectability of covert communication in multi-antenna broadcast channels.

关键词： beamforming covert communication multi-antenna broadcast channels OFDM

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Can Industrial Structure Upgrading Restrain Industrial Land Expansion?Evidence from China

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Chinese geographical Science 2024年第3期34卷 504-518页

作者： CHEN Wei LI qiao ZHANg Sun ZHOU Xue College of Economics and Management Northwest A&F UniversityYangling Shaanxi 712100China Institute of geographic Sciences&Natural Resources Research Chinese Academy of SciencesBeijing 100101China

China has made great achievements in industrial development and is transforming into a powerful manufacturing ***,the industrial land scale is also ***,whether industrial structure upgrading achieves the purpose of restraining industrial land expansion remains *** calculating the industrial land structure index(ILSI)and industrial land expansion scale(ILES),this study analyzed their temporal and spatial distribution characteristics at both regional and city levels from 2007to 2020 in *** show that industrial land expansion presents a different trend in the four regions,the ILES in the eastern region is the largest,and the speed of industrial land expansion has declined since 2013,but it has gradually increased since *** ILSI of the eastern and central regions is higher than that of the western and northeastern ***,a spatial Durbin model(SDM)has been established to estimate the spatial effect of industrial structure upgrading on industrial land expansion from 2007 ***,industrial structure upgrading has not slowed industrial land *** eastern and western regions require a greater amount of industrial land while upgrading the industrial *** improvement of the infrastructure level and international trade level has promoted industrial land expansion.

关键词： industrial development industrial structure upgrading industrial land expansion regional differences China

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Lithium-Ion Charged Polymer Channels Flattening Lithium Metal Anode

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Nano-Micro Letters 2024年第4期16卷 379-393页

作者： Haofan Duan Yu You gang Wang Xiangze Ou Jin Wen qiao Huang Pengbo Lyu Yaru Liang Qingyu Li Jianyu Huang yun‑Xiao Wang Hua‑Kun Liu Shi Xue Dou Wei‑Hong Lai Hunan Provincial Key Laboratory of Thin Film Materials and Devices School of Material Sciences and EngineeringXiangtan UniversityXiangtan 411105People’s Republic of China guangxi Key Laboratory of Low Carbon Energy Materials School of Chemical and Pharmaceutical ScienceGuangxi Normal UniversityGuilin 541004People’s Republic of China Institute for Superconducting and Electronic Materials Australian Institute of Innovative MaterialsUniversity of WollongongInnovation CampusSquires WayNorth WollongongNSW 2500Australia Institute of Energy Materials Science University of Shanghai for Science and TechnologyShanghai 200093People’s Republic of China

The concentration difference in the near-surface region of lithium metal is the main cause of lithium dendrite *** this issue will be key to achieving high-performance lithium metal batteries(LMBs).Herein,we construct a lithium nitrate(LiNO_(3))-implanted electroactiveβphase polyvinylidene fluoride-co-hexafluoropropylene(PVDF-HFP)crystalline polymorph layer(PHL).The electronegatively charged polymer chains attain lithium ions on the surface to form lithium-ion charged *** channels act as reservoirs to sustainably release Li ions to recompense the ionic flux of electrolytes,decreasing the growth of lithium *** stretched molecular channels can also accelerate the transport of Li *** combined effects enable a high Coulombic efficiency of 97.0%for 250 cycles in lithium(Li)||copper(Cu)cell and a stable symmetric plating/stripping behavior over 2000 h at 3 mA cm^(-2)with ultrahigh Li utilization of 50%.Furthermore,the full cell coupled with PHL-Cu@Li anode and Li Fe PO_(4) cathode exhibits long-term cycle stability with high-capacity retention of 95.9%after 900 ***,the full cell paired with LiNi_(0.87)Co_(0.1)Mn_(0.03)O_(2)maintains a discharge capacity of 170.0 mAh g^(-1)with a capacity retention of 84.3%after 100 cycles even under harsh condition of ultralow N/P ratio of *** facile strategy will widen the potential application of LiNO_(3)in ester-based electrolyte for practical high-voltage LMBs.

关键词： Polymer ionic channel Li metal batteries Artificial protective layer Uniform Li deposition Electrochemical performances

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Towards kernelizing the classifier for hyperbolic data

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Frontiers of Computer Science 2024年第1期18卷 17-31页

作者： Meimei YANg qiao LIU Xinkai SUN Na SHI Hui XUE School of Computer Science and Engineering Southeast UniversityNanjing 210096China MOE Key Laboratory of Computer Science and Information Integration(Southeast University) Nanjing 210096China

Data hierarchy,as a hidden property of data structure,exists in a wide range of machine learning applications.A common practice to classify such hierarchical data is first to encode the data in the Euclidean space,and then train a Euclidean ***,such a paradigm leads to a performance drop due to distortion of data embedding in the Euclidean *** relieve this issue,hyperbolic geometry is investigated as an alternative space to encode the hierarchical data for its higher ability to capture the hierarchical *** methods cannot explore the full potential of the hyperbolic geometry,in the sense that such methods define the hyperbolic operations in the tangent plane,causing the distortion of data *** this paper,we develop two novel kernel formulations in the hyperbolic space,with one being positive definite(PD)and another one being indefinite,to solve the classification tasks in hyperbolic *** PD one is defined via mapping the hyperbolic data to the Drury-Arveson(DA)space,which is a special reproducing kernel Hilbert space(RKHS).To further increase the discrimination of the classifier,an indefinite kernel is further defined in the Krein ***,we design a 2-layer nested indefinite kernel which first maps hyperbolic data into the DA spaces,followed by a mapping from the DA spaces to the Krein *** experiments on real-world datasets demonstrate the superiority ofthe proposed kernels.

关键词： data hierarchy hyperbolic cgeometry drury-arveson space krein space

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A novel adaptive coordinated tracking control scheme for a morphing aircraft with telescopic wings

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Chinese Journal of Aeronautics 2024年第2期37卷 148-162页

作者： Enmei WANg Hao LU Jianchun ZHANg Chenliang WANg Jianzhong qiao Hangzhou Innovation Institute Beihang UniversityHangzhou 310051China School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China

Inspired by flight biology,morphing flight technology has great potential to improve the adaptability and maneuverability of *** paper is devoted to the flight control problem of morphing aircraft,and aimed at safe and fuel-saving flight through morphing ***,the longitudinal dynamics of a morphing aircraft with telescopic wings is modelled as a strict-feedback nonlinear *** fitting the expression of aerodynamic parameters by the mor-phing ratio,the model uncertainties induced by morphing errors are embedded in the *** meet the safety and fuel-saving requirements,an Adaptive Coordinated Tracking Control Scheme(ACTCS)is then proposed,which consists of a morphing control module and a tracking control *** the morphing control module,an on-line morphing decision model is given in an optimization process with respect to the morphing ratio,and a second-order tracking filter is introduced to smooth the decision output and ensure the physical *** the tracking control module,the novel adaptive controllers for the velocity and altitude subsystems are proposed based on the dynamic surface control method,in which adaptive mechanisms are designed to com-pensate for the model ***,the proposed ACTCS is simulated in nine different cases of the test flight mission,to verify its effectiveness,robustness and fuel-saving effect.

关键词： Morphing aircraft Adaptive tracking control Morphing decision Dynamic surface control Morphing error

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