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Design,Simulation and Kinematic Validation of a Hip Prosthetic Mechanism with a Multimotor Function

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Journal of Bionic Engineering 2024年第3期21卷 1321-1333页

作者： Majun song Zhongyi Li Jingjing Jiang Weihai Chen Sheng guo Hao zheng Lianzheng Niu Hangzhou Innovation Institute Beihang UniversityHangzhou310051China Hangzhou Huacheng Software Technology Co.Ltd. Hangzhou310051China School of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijing100044China

We previously developed a powered hip prosthetic mechanism with kinematic functions of hip flexion-extension and abduction-adduction,and its theoretical and simulation-based kinematics were *** internal-external hip rotation has a positive effect on the movements of human lower limbs according to medical research,we developed a novel hip prosthetic mechanism based on a previous hip prosthesis that possesses motion characteristics similar to those of a human bionic hip,and the motion characteristics of multiple Degrees-of-Freedom(DoFs)were analyzed after kinematic ***,a walking model of the human‒machine model was established,and the walking stability of an amputee,which reflects the rehabilitation effect,was explored while the hip prosthetic mechanism considered the internal-external rotation of the ***,a prototype and its verification platform were built,and kinematic validation of the hip prosthetic mechanism was carried *** results showed that the designed Parallel Mechanism(PM)possesses human-like motion characteristics similar to those of a human bionic hip and can be used as a hip ***,the existing motion characteristic of internal-external hip rotation can enhance the walking stability of an amputee via this hip prosthetic mechanism.

关键词： Hip prosthetic mechanism Parallel mechanism Walking stability Kinematic validation

Predicting impact forces on pipelines from deep-sea fluidized slides:A comprehensive review of key factors

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International Journal of Mining Science and Technology 2024年第2期34卷 211-225页

作者： Xingsen guo Ning Fan Defeng zheng Cuiwei Fu Hao Wu Yanjun Zhang Xiaolong song Tingkai Nian State Key Laboratory of Coastal and Offshore Engineering Dalian University of TechnologyDalian 116024China Department of Civil Environmentaland Geomatic EngineeringUniversity College LondonLondon WC1E 6BTUnited Kingdom Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering Ocean University of ChinaQingdao 266100China State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu 610059China College of Civil Engineering and Architecture Wenzhou UniversityWenzhou 325035China Key Laboratory of Engineering and Technology for Soft Soil Foundation and Tideland Reclamation of Zhejiang Province Wenzhou 325035China Zhejiang International Science and Technology Cooperation Base of Ultra-soft Soil Engineering and Smart Monitoring Wenzhou 325035China School of Geography Liaoning Normal UniversityDalian 116029China China Railway First Survey and Design Institute Group Co. Ltd.Xi’an 710043China Department of Geotechnical Engineering Nanjing Hydraulic Research InstituteNanjing 210024China Wuhan Center China Geological Survey(Central South China Innovation Center for Geosciences)Wuhan 430205China State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines Anhui University of Science and TechnologyHuainan 232001China

Deep-sea pipelines play a pivotal role in seabed mineral resource development,global energy and resource supply provision,network communication,and environmental ***,the placement of these pipelines on the seabed surface exposes them to potential risks arising from the complex deep-sea hydrodynamic and geological environment,particularly submarine *** incidents have highlighted the substantial damage to pipelines due to ***,deep-sea fluidized slides(in a debris/mud flow or turbidity current physical state),characterized by high speed,pose a significant *** assessing the impact forces exerted on pipelines by fluidized submarine slides is crucial for ensuring pipeline *** study aimed to provide a comprehensive overview of recent advancements in understanding pipeline impact forces caused by fluidized deep-sea slides,thereby identifying key factors and corresponding mechanisms that influence pipeline impact *** factors include the velocity,density,and shear behavior of deep-sea fluidized slides,as well as the geometry,stiffness,self-weight,and mechanical model of ***,the interface contact conditions and spatial relations were examined within the context of deep-sea slides and their interactions with *** upon a thorough review of these achievements,future directions were proposed for assessing and characterizing the key factors affecting slide impact loading on pipelines.A comprehensive understanding of these results is essential for the sustainable development of deep-sea pipeline projects associated with seabed resource development and the implementation of disaster prevention measures.

关键词： Deep-sea fluidized slides Pipes Impact forces Shear behavior of slides Interface contact conditions Spatial relation

Damage evolution of rock-encased-backfill structure under stepwise cyclic triaxial loading

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第2期16卷 597-615页

作者： Xin Yu Yuye Tan Weidong song John Kemeny Shengwen Qi Bowen zheng songfeng guo Key Laboratory of Shale Gas and Geoengineering Institute of Geology and GeophysicsChinese Academy of SciencesBeijing100089China Innovation Academy for Earth Science Chinese Academy of SciencesBeijing100089China University of Chinese Academy of Sciences Beijing100049China School of Civil and Resources Engineering University of Science and Technology BeijingBeijing100083China Key Laboratory of High-Efficient Mining and Safety of Metal Mines(Ministry of Education of China) University of Science and Technology BeijingBeijing100083China Department of Mining and Geological Engineering University of ArizonaTucsonAZ86721USA

Rock-encased-backfill(RB)structures are common in underground mining,for example in the cut-andfill and stoping *** understand the effects of cyclic excavation and blasting activities on the damage of these RB structures,a series of triaxial stepwise-increasing-amplitude cyclic loading experiments was conducted with cylindrical RB specimens(rock on outside,backfill on inside)with different volume fractions of rock(VF=0.48,0.61,0.73,and 0.84),confining pressures(0,6,9,and 12 MPa),and cyclic loading rates(200,300,400,and 500 N/s).The damage evolution and meso-crack formation during the cyclic tests were analyzed with results from stress-strain hysteresis loops,acoustic emission events,and post-failure X-ray 3D fracture *** results showed significant differences between cyclic and monotonic loadings of RB specimens,particularly with regard to the generation of shear microcracks,the development of stress memory and strain hardening,and the contact forces and associated friction that develops along the rock-backfill *** important finding is that as a function of the number of cycles,the elastic strain increases linearly and the dissipated energy increases ***,compared with monotonic loading,the cyclic strain hardening characteristics are more sensitive to rising confining pressures during the initial compaction *** finding is that compared with monotonic loading,more shear microcracks are generated during every reloading stage,but these microcracks tend to be dispersed and lessen the likelihood of large shear fracture *** transition from elastic to plastic behavior varies depending on the parameters of each test(confinement,volume fraction,and cyclic rate),and an interesting finding was that the transformation to plastic behavior is significantly lower under the conditions of 0.73 rock volume fraction,400 N/s cyclic loading rate,and 9 MPa *** the findings have important practical implications on t

关键词： Rock and backfill Triaxial cyclic loading Volume fraction Damage evolution 3D visualization

Study on thermal cycling ageing resistance of performances of polypropylene/elastomer/boron nitride nanocomposites for high voltage direct current cable insulation

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High Voltage 2024年第3期9卷 556-565页

作者： Jing Li Yu Gao zheng song Baixin Liu Chenyi guo Yu Chen Junguo Gao Boxue Du School of Electrical and Information Engineering Tianjin UniversityTianjinChina State Grid Tianjin Chengxi Electric Power Supply Branch TianjinChina State Key Laboratory of Electrical Insulation and Power Equipment Xi'an Jiaotong UniversityXi'anChina Key Laboratory of Engineering Dielectrics and Its Application Ministry of EducationHarbin University of Science and TechnologyHarbinChina

The influences of thermal cycling ageing on structures and insulation performances of polypropylene(PP)/elastomer/boron nitride(BN)nanocomposites are *** Melt blending method was used to prepare the nanocomposites,in which propylene-based elastomer(PBE)or ethylene-octene copolymer elastomer(EOC)was contained for ***,the samples were treated using a thermal cycling process with a temperature range from-30 to 150℃,and the number of thermal cycles was set from 0 to *** electron microscope(SEM),Fourier transform infrared spectroscopy(FTIR),differential scanning calorimetry and X-ray diffraction measurements were taken to facilitate the comprehension of structural ***,measurements were taken to assess the trap distribution and direct current(DC)breakdown strength of the *** obtained results revealed that following thermal cycling ageing,the morphology and crystallinity of PP/PBE/BN remained almost *** contrast,PP/EOC/BN exhibited substantial microstructural damage accompanied by a significant reduction in *** the number of thermal cycles increased,the trap level and DC breakdown strength of PP/PBE/BN were maintained at high levels,while those of PP/EOC/BN initially remained stable but then experienced a sharp *** is sug-gested that the addition of BN nanoparticles enhances the thermal cycling ageing resis-tance of the PP/PBE blend,whereas it weakens this resistance of the PP/EOC blend.

关键词： cycling resistance thermal

Body size induced changes in metabolic carbon of soil nematodes under N deposition and precipitation regime change in a temperate grassland

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Ecological Processes 2024年第1期13卷 120-131页

作者： Shuyan Cui Xiaomei Mo guo zheng College of Life Science Shenyang Normal University

Background Global climate change has resulted in precipitation regimes exhibiting an increasing trend in rainfall intensity but a reduction in its frequency. Nitrogen(N) deposition is a crucial component of the global N cycling. Nematode body size is a trait that responds to climate change and is used as a standard trait-based indicator in soil community analysis. Variations in body size influence metabolic carbon(C). We examined the ways by which body size and metabolic C of nematodes respond to changing precipitation regimes and how N deposition regulates these responses by an 8-year manipulative *** Nematode body size was indicated by the community-weighted mean(CWM) mass. We quantified C metabolism components of soil nematodes including production C, respiration C, and corresponding C use efficiency(CUE) under different precipitation intensities and N addition in a semi-arid steppe on the Mongolian Plateau. The Mantel test was used to determine the correlations between CWM, CUE and environmental factors. The partial least squares path modeling(PLS-PM) was conducted to quantify direct or indirect contributions among latent *** We found that heavy precipitation intensity increased the CWM mass of total nematodes and omnivorespredators without N addition. N addition decreased CWM mass of bacterivores across all the precipitation intensity treatments. Stronger precipitation intensities might be favorable for nematode production and respiration C. Variations in the nematode CWM mass drove the CUE to change with N *** Our findings provide new insights into the mechanisms underlying nematode body size and C metabolism, and highlight that explorative studies, such as manipulative experiments, are needed to identify traits underlying size-related effects and to investigate how they affect CUE of nematodes. These efforts may increase our understanding of how changes in precipitation regimes and N deposition may alter soil nema

关键词： Community-weighted mean Metabolic footprint Nitrogen addition Precipitation intensity

Studies of an event-building algorithm of the readout system for the twin TPCs in HFRS

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Nuclear Science and Techniques 2024年第4期35卷 82-95页

作者： Jing Tian Zhi-Peng Sun song-Bo Chang Yi Qian Hong-Yun Zhao zheng-guo Hu Xi-Meng Chen Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China School of Nuclear Science and Technology University of LanzhouLanzhou 730000China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China Advanced Energy Science and Technology Guangdong LaboratoryHuizhou 516000China

The High-energy Fragment Separator(HFRS),which is currently under construction,is a leading international radioactive beam *** sets of position-sensitive twin time projection chamber(TPC)detectors are distributed on HFRS for particle identification and beam *** twin TPCs'readout electronics system operates in a trigger-less mode due to its high counting rate,leading to a challenge of handling large amounts of *** address this problem,we introduced an event-building *** algorithm employs a hierarchical processing strategy to compress data during transmission and *** addition,it reconstructs twin TPCs'events online and stores only the reconstructed particle information,which significantly reduces the burden on data transmission and storage *** studies demonstrated that the algorithm accurately matches twin TPCs'events and reduces more than 98%of the data volume at a counting rate of 500 kHz/channel.

关键词： High counting rate Twin TPCs Trigger-less Readout electronics Event building Hierarchical data processing

Protection of Omicron Sub-Lineage Infection Against Reinfection with Another Omicron Sub-Lineage:Systematic Review,Meta-Analysis,and Meta-Regression-Worldwide,2022-2023

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China CDC weekly 2024年第26期6卷 624-628,I0001-I0009页

作者： Xu guo Zuyao Cheng Junhong Li Yudan song Hui zheng Yamin Wang Chao Ma Zijian Feng National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Disease National Immunization ProgramChinese Center for Disease Control and PreventionBeijingChina Chinese Preventive Medicine Association BeijingChina

Summary What is already known about this topic?Both the decline in immunity over time and the evolution of the virus play a role in the level of protection offered by a prior *** is added by this report?Point estimates indicated variations in protection levels based on the initial infecting variant and the reinfecting *** was a consistent correlation between real-world protection,antigenic distance,and humoral immunity ***,shorter antigenic distances and higher humoral immunity levels corresponded to enhanced real-world *** are the implications for public health practice?Our findings suggest that virological and immunological studies could help identify and assess the epidemic risk posed by new variants before they become *** incorporation of the latest variants into the antigen components of the coronavirus disease 2019(COVID-19)vaccines can significantly contribute to effective epidemic prevention and control measures.

关键词： immunity prevention shorter

Differentially private SGD with random features

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Applied Mathematics(A Journal of Chinese Universities) 2024年第1期39卷 1-23页

作者： WANG Yi-guang guo zheng-chu Polytechnic Institute of Zhejiang University Zhejiang UniversityHangzhou 310015China School of Mathematical Sciences Zhejiang UniversityHangzhou 310058China

In the realm of large-scale machine learning,it is crucial to explore methods for reducing computational complexity and memory demands while maintaining generalization ***,since the collected data may contain some sensitive information,it is also of great significance to study privacy-preserving machine learning *** paper focuses on the performance of the differentially private stochastic gradient descent(SGD)algorithm based on random *** begin,the algorithm maps the original data into a lowdimensional space,thereby avoiding the traditional kernel method for large-scale data storage ***,the algorithm iteratively optimizes parameters using the stochastic gradient descent ***,the output perturbation mechanism is employed to introduce random noise,ensuring algorithmic *** prove that the proposed algorithm satisfies the differential privacy while achieving fast convergence rates under some mild conditions.

关键词： learning theory differential privacy stochastic gradient descent random features reproducing kernel Hilbert spaces

Combined use of fly ash and silica to prevent the long-term strength retrogression of oil well cement set and cured at HPHT conditions

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Petroleum Science 2024年第2期21卷 1122-1134页

作者： guo-Dong Cheng Xue-Yu Pang Jin-Sheng Sun zheng-song Qiu Chuang-Chuang Wang Jian-Kun Qin Ning Li School of Petroleum Engineering China University of Petroleum(East China)Qingdao266580ShandongChina National Key Laboratory of Deep Oil and Gas China University of Petroleum(East China)Qingdao266580ShandongChina Oil and Gas Engineering Research Institute(Tarim Oilfield Company) China National Petroleum CorporationTarim841000XinjiangChina

The long-term strength retrogression of silica-enriched oil well cement poses a significant threat to wellbore integrity in deep and ultra-deep wells, which is a major obstacle for deep petroleum and geothermal energy development. Previous attempts to address this problem has been unsatisfactory because they can only reduce the strength decline rate. This study presents a new solution to this problem by incorporating fly ash to the traditional silica-cement systems. The influences of fly ash and silica on the strength retrogression behavior of oil well cement systems directly set and cured under the condition of 200°C and 50 MPa are investigated. Test results indicate that the slurries containing only silica or fly ash experience severe strength retrogression from 2 to 30 d curing, while the slurries containing both fly ash and silica experience strength enhancement from 2 to 90 d. The strength test results are corroborated by further evidences from permeability tests as well as microstructure analysis of set cement. Composition of set cement evaluated by quantitative X-ray diffraction analyses with partial or no known crystal structure(PONKCS) method and thermogravimetry analyses revealed that the conversion of amorphous C-(A)-S-H to crystalline phases is the primary cause of long-term strength *** addition of fly ash can reduce the initial amount of C-(A)-S-H in the set cement, and its combined use with silica can prevent the crystallization of C-(A)-S-H, which is believed to be the working mechanism of this new admixture in improving long-term strength stability of oil well cement systems.

关键词： Fly ash Long-term strength retrogression High temperature Quantitative X-ray diffraction(QXRD) Partial or no known crystal structure(PONKCS)