检索结果-南通市图书馆

Shear mechanical properties and frictional sliding responses of rough joint surfaces under dynamic normal displacement conditions

引用

Journal of Central South University 2024年第7期31卷 2393-2410页

作者： ZHU Qiang YIN Qian TAO Zhi-gang HE Man-chao ZHENG Bo-wen JING Hong-wen REN Shu-lin ZHANG Qiang MENG Bo bai dong-feng WU Sai-sai WU Jiang-yu State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering Xuzhou 221116China State Key Laboratory for Geomechanics&Deep Underground Engineering China University of Mining and Technology(Beijing)Beijing 100083China Key Laboratory of Shale Gas and Geoengineering Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China CCCC First Highway Survey and Design Research Institute Co. Ltd.Xi’an 710075China

A comprehensive understanding of the dynamic frictional characteristics in rock joints under high normal load and strong confinement is essential for ensuring the safety of deep engineering construction and mitigating geological *** study conducted shear experiments on rough rock joints under displacement-controlled dynamic normal loads,investigating the shear behaviors of joints across varying initial normal loads,normal loading frequencies,and normal loading *** results showed that the peak/valley shear force values increased with initial normal loads and normal loading frequencies but showed an initial increase followed by a decrease with normal loading *** normal loading can either increase or decrease shear strength,while this study demonstrates that higher frequencies lead to enhanced *** initial normal loading and normal loading frequency result in a gradual decrease in joint roughness coefficient(JRC)values of joint surfaces after *** correlations existed between frictional energy dissipation and peak shear forces,while post-shear joint surface roughness exhibited a negative correlation with peak shear forces through linear regression *** study contributes to a better understanding of the sliding responses and shear mechanical characteristics of rock joints under dynamic disturbances.

关键词： dynamic normal displacement shear strength variations phase lag phenomenon stick-slip

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Community structure and species diversity dynamics of a subtropical evergreen broad-leaved forest in China:2005 to 2020

引用

Plant Diversity 2024年第1期46卷 70-77页

作者： Shi-Guang Wei Lin Li Kun-dong bai Zhi-feng Wen Jing-Gang Zhou Qin Lin Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection(Guangxi Normal University) Ministry of EducationGuilin 541004GuangxiChina School of Life&Environmental Sciences Guilin University of Electronic TechnologyGuilin 541004GuangxiChina Guangxi Key Laboratory of Landscape Resources Conservation and Sustainable Utilization in Lijiang River Basin Guilin 541004GuangxiChina Key Laboratory of Vegetation Restoration and Management of South China Botanical Garden of Degraded Ecosystems Chinese Academy of SciencesGuangzhou 510650GuangdongChina Center of Plant Ecology Core Botanical GardensChinese Academy of SciencesGuangzhou 510650GuangdongChina

Here,we characterize the temporal and spatial dynamics of forest community structure and species diversity in a subtropical evergreen broad-leaved forest in *** found that community structure in this forest changed over a 15-year ***,renewal and death of common species was large,with the renewal of individuals mainly concentrated within a few populations,especially those of Aidia canthioides and Cryptocarya *** numbers of individual deaths for common species were concentrated in the small and mid-diameter *** spatial distribution of community species diversity fluctuated in each monitoring period,showing a more dispersed diversity after the 15-year study period,and the coefficient of variation on quadrats *** 2010,the death and renewal of the community and the spatial variation of species diversity were different compared to other survey *** weather may have affected species regeneration and community stability in our subtropical monsoon evergreen broad-leaved *** findings suggest that strengthening the monitoring and management of the forest community will help better understand the long-and short-term causes of dynamic fluctuations of community structure and species diversity,and reveal the factors that drive changes in community structure.

关键词： Community structure Death and renewal dynamics Species diversity dynamics South subtropical forest

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Primitive functional groups directed distinct photocatalytic performance of imine-linked donor-acceptor covalent organic frameworks

引用

Nano Research 2024年第6期17卷 4994-5001页

作者： Xitong Ren Jiajie Sun Yusen Li feng bai Key Laboratory for Special Functional Materials of Ministry of Education National and Local Joint Engineering Research Center for High-Efficiency Display and Lighting TechnologySchool of Materials Science and Engineeringand Collaborative Innovation Center of Nano Functional Materials and ApplicationsHenan UniversityKaifeng 475004China School of Physics and Electronics Henan UniversityKaifeng 475004China

The combination of donor-acceptor(D-A)structures presents a viable strategy for fabricating covalent organic frameworks(COFs)with exceptional photocatalytic ***,the selection of functional groups on donor or acceptor building blocks and their effect on the macroscopic properties of COFs are *** this study,we tactfully synthesized a pair of Py-DBT-COFs from the same pyrene(Py)donor and 4,7-diphenylbenzo[c][1,2,5]thiadiazole(DBT)acceptor cores with distinct primitive functional *** primitive functional groups of building units determine the photocatalytic properties of corresponding ***,Py-C-DBT-COF synthesized from Py-4CHO and DBT-2NH_(2)showcases a splendid H_(2)evolution rate as high as 21,377.7μmol/(g·h)(with 5 wt.%Pt)originating from better charge transfer capacity,which is significantly superior to that of Py-N-DBT-COF constructed from Py-4NH_(2)and *** distinct photocatalytic performances of the two COFs are demonstrated to originate from the different charge separation and transfer *** work supplies a new avenue for optimizing the photocatalytic performance of D-A COFs from the perspective of primitive functional group selections.

关键词： covalent organic frameworks functional group donor-acceptor photocatalysis

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Metallurgy and Solidification Microstructure Control of Fusion-Based Additive Manufacturing Fabricated Metallic Alloys:A Review

引用

Acta Metallurgica Sinica(English Letters) 2024年第1期37卷 29-53页

作者： Qiang Li Xing-Ran Li bai-Xin dong Xiao-Long Zhang Shi-Li Shu feng Qiu Lai-Chang Zhang Zhi-Hui Zhang Key Laboratory of Bionic Engineering(Ministry of Education) and College of Bionic Science and EngineeringJilin UniversityChangchun130022China Institute of Structured and Architected Materials Liaoning Academy of MaterialsShenyang110167China Key Laboratory of Automobile Materials Ministry of Education and Department of Materials Science and EngineeringJilin UniversityChangchun130025China School of Mechanical and Aerospace Engineering Jilin UniversityChangchun130025China School of Engineering Edith Cowan University270 Joondalup DriveJoondalupPerthWA6027Australia

The metal-based additive manufacturing(AM),also referred to as metal 3D printing,has drawn particular interest because it enables direct creation,aided by computationally-directed path design,of intricate components with site-specific compositions and geometrical requirements as well as low buy-to-fly *** the last two decades,the objective of this revolutionary technology has been shifting from only“rapid prototyping”to advanced manufacturing of special high-end products or devices,which,in many aspects,outperform conventional manufacturing *** fusion-based AM,significant progress has been achieved in understanding the processing window of macroscopic scales,non-equilibrium metallurgy of mesoscale scales,and grain evolution of microscopic *** the versatile capacity of AM facilitates new avenues for discovering advanced materials and structures,their potential has still not been fully *** the unique non-equilibrium solidification during the AM process,coarse columnar grains with strong textures are usually developed along the build direction,which downgrades the mechanical *** push the limits of this digital manufacturing,this review attempts to provide in-depth and comprehensive overviews of the recent progress in understanding the evolution and control of the as-built microstructure that has been made recently and the challenges encountered during the AM process.

关键词： Additive manufacturing Temperature field Microstructure control Nanoparticles Functionally graded materials

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Reliable calculations of nuclear binding energies by the Gaussian process of machine learning

引用

Nuclear Science and Techniques 2024年第6期35卷 130-144页

作者： Zi-Yi Yuan dong bai Zhen Wang Zhong-Zhou Ren School of Physics Science and Engineering Tongji UniversityShanghai 200092China College of Science Hohai UniversityNanjing 211100China Key Laboratory of Advanced Micro-Structure Materials Ministry of EducationShanghai 200092China

Reliable calculations of nuclear binding energies are crucial for advancing the research of nuclear physics. Machine learning provides an innovative approach to exploring complex physical problems. In this study, the nuclear binding energies are modeled directly using a machine-learning method called the Gaussian process. First, the binding energies for 2238 nuclei with Z > 20 and N > 20 are calculated using the Gaussian process in a physically motivated feature space, yielding an average deviation of 0.046 MeV and a standard deviation of 0.066 MeV. The results show the good learning ability of the Gaussian process in the studies of binding energies. Then, the predictive power of the Gaussian process is studied by calculating the binding energies for 108 nuclei newly included in AME2020. The theoretical results are in good agreement with the experimental data, reflecting the good predictive power of the Gaussian process. Moreover, the α-decay energies for 1169 nuclei with 50 ≤ Z ≤ 110 are derived from the theoretical binding energies calculated using the Gaussian process. The average deviation and the standard deviation are, respectively, 0.047 MeV and 0.070 MeV. Noticeably, the calculated α-decay energies for the two new isotopes ^ (204 )Ac(Huang et al. Phys Lett B 834, 137484(2022)) and ^ (207) Th(Yang et al. Phys Rev C 105, L051302(2022)) agree well with the latest experimental data. These results demonstrate that the Gaussian process is reliable for the calculations of nuclear binding energies. Finally, the α-decay properties of some unknown actinide nuclei are predicted using the Gaussian process. The predicted results can be useful guides for future research on binding energies and α-decay properties.

关键词： Nuclear binding energies decay Machine learning Gaussian process

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Hydrodynamic analysis of carbon nanotube clusters in distributor-less conical fluidized beds with step-by-step scaling

引用

Chinese Journal of Chemical Engineering 2024年第3期67卷 117-125页

作者： Tianle Zhang Wenjuan bai Qianpeng dong Dianming Chu Lianlian Wang Yan He Shandong Engineering Laboratory for Preparation and Application of High-performance Carbon-Materials College of Electromechanical EngineeringQingdao University of Science and TechnologyQingdao 266061China Shandong Dazhan Nano Materials Co. Ltd.Binzhou 256220China

As a high-performance material with great application potential,the application of carbon nanotubes has been limited by their production volume.A distributor-less conical fluidized bed is the main equipment used in the industrial production of carbon *** improve the production volume and product quality of carbon nanotubes,the study of fluidized-bed-diameter scaling is *** different diameters of distributor-less conical fluidized beds were established,and then the particle behavior and bubble characteristics of carbon nanotube clusters at these bed diameters were ***-series and wavelet analysis methods were used to analyze the pressure-fluctuation signals inside the fluidized *** showed that the distributor-less design caused the airflow to break through the middle of the bed,which did not change with the change in bed *** powder-bridging phenomenon of carbon nanotube clusters in a 100-mm-diameter fluidized bed was related to the special microstructure of carbon nanotube *** frequency of pressure fluctuations in the bed decreased nonlinearly with increasing bed *** study can guide the design and scale-up of distributor-less conical fluidized beds,especially for the scale-up of carbon nanotube production equipment,which can contribute to the improvement of carbon nanotubes’capacity and quality in industrial production.

关键词： Carbon nanotubes Fluidized bed Multiphase flow Scale-up Multiscale

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Crack identification in concrete, using digital image correlation and neural network

引用

Frontiers of Structural and Civil Engineering 2024年第4期18卷 536-550页

作者： Jingyi WANG dong LEI Kaiyang ZHOU Jintao HE Feipeng ZHU Pengxiang bai College of Mechanics and Materials Hohai UniversityNanjing 211100China

In engineering applications,concrete crack monitoring is very *** methods are of low efficiency,low accuracy,have poor timeliness,and are applicable in only a limited number of ***,more comprehensive detection of concrete damage under different scenarios is of high value for practical engineering *** image correlation(DIC)technology can provide a large amount of experimental data,and neural network(NN)can process very rich ***,NN,including convolutional neural networks(CNN)and back propagation neural networks(BP),can be combined with DIC technology to analyze experimental data of three-point bending of plain concrete and four-point bending of reinforced *** addition,strain parameters can be used for training,and displacement parameters can be added for comprehensive *** data obtained by DIC technology are grouped for training,and the recognition results of NN show that the combination of strain and displacement parameters,i.e.,the response of specimen surface and whole body,can make results more objective and *** identification results obtained by CNN and BP show that these technologies can accurately identify *** identification results for reinforced concrete specimens are less affected by noise than those of plain concrete *** is more convenient because it can identify some features directly from images,recognizing the cracks formed by macro *** can issue early warning of the microscopic cracks,but it requires a large amount of data and *** can be seen that CNN is more intuitive and efficient in image processing,and is suitable when low accuracy is adequate,while BP is suitable for occasions with greater accuracy *** two tools have advantages in different situations,and together they can play an important role in engineering monitoring.

关键词： digital image correlation convolutional neural network back propagation neural neural network damage detection concrete

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

In-situ construction of PDOL electrolyte with dual-reinforced stable interface for high-voltage lithium metal batteries

引用

Science China Chemistry 2024年第5期67卷 1664-1671页

作者： Yingkang Wu Yuzhou bai Wujie dong Xue Wang Wenqin Ma Fuqiang Huang State Key Lab of Metal Matrix Composites School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China School of Physical Science and Technology Shanghai Tech UniversityShanghai 201210China Shanghai Institute of Ceramics Chinese Academy of SciencesShanghai 200050China

In-situ polymerized electrolytes significantly enhance the interfacial compatibility of lithium metal batteries(LMBs). Typically,in-situ polymerized 1,3-dioxolane(PDOL) exhibits low interfacial resistance, yet still suffers from low ionic conductivity and a narrow electrochemical stability window(ESW). Here, an ultra-stable PDOL-based polymer electrolyte is developed by incorporating plasticizers of tetramethylene sulfone(TMS) and fluorinated ethylene carbonate(FEC) into the 3D cross-linked network, achieving a significant enhancement in the transport capacity and efficiency of Li-ion. The ionic conductivity reaches3.63×10^(-4)S cm^(-1)even at room temperature, and the transference number(tLi^(+)) is even higher at 0.85. Furthermore, the ESW of this electrolyte can be increased to 4.5 V with the addition of TMS, which forms a thin and robust antioxidant cathode-electrolyte interface(CEI) on the surface of high-voltage LiCoO_(2). FEC generates an inorganic-rich solid-electrolyte interface(SEI) on the Li anode, which effectively inhibits the growth of lithium dendrites. Benefiting from the aforementioned advantages, the highvoltage lithium metal battery demonstrates outstanding long-cycle stability, with 93.2% capacity retention after 200 cycles. This work offers a straightforward and accessible method for the practical implementation of high energy density in-situ polymerized solid-state LMBs.

关键词： solid polymer electrolyte in-situ polymerization PDOL high-voltage LMBs

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Self-doping active sites in microbe-derived carbonaceous electrocatalysts for the oxygen reduction reaction performance

引用

Nano Research 2024年第8期17卷 6803-6819页

作者： Xiaofeng Xiao Xiaochun Tian Junpeng Li Fan Yang Rui bai feng Zhao Key Laboratory of Urban Pollutant Conversion Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China University of Chinese Academy of Sciences Beijing 100049China

Microorganisms are rich in heteroatoms,which can be self-doped to form active sites during pyrolysis and loaded on microbederived carbonaceous *** recent years,microbe-derived carbonaceous materials,characterized with abundant selfdoping sites,have been continuously developed as cost-effective electrocatalysts for oxygen reduction reaction(ORR).To fully unlock the catalytic potential of microbe-derived carbonaceous materials,a comprehensive analysis of catalytic sites and mechanisms for ORR is *** paper provides a summary of the ORR catalytic performance of microbe-derived carbonaceous materials reported to date,with a specific focus on the self-doping sites introduced during their pyrolytic *** highlights the mono-or co-doping sites involving nonmetallic elements such as oxygen(O),nitrogen(N),phosphorus(P),and sulfur(S)atoms,as well as covers the doping of metallic iron(Fe)atoms with various coordination configurations in microbe-derived carbonaceous *** the impact of these self-doping sites on ORR catalytic performance can guide the design of doping sites in microbe-derived carbonaceous *** approach has the potential to maximize electrocatalytic activity of microbe-derived carbonaceous materials and contributes to the development of more efficient and cost-effective carbonaceous electrocatalysts.

关键词： electrocatalysis heteroatoms self-doped single atom catalyst microbe-derived carbonaceous material

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Weak Fault Feature Extraction of the Rotating Machinery Using Flexible Analytic Wavelet Transform and Nonlinear Quantum Permutation Entropy

引用

Computers, Materials & Continua 2024年第6期79卷 4513-4531页

作者： Lili bai Wenhui Li He Ren feng Li TaoYan Lirong Chen College of Aeronautics and Astronautics Taiyuan University of TechnologyTaiyuan030024China Commercial Aircraft Corporation of China Ltd.Shanghai200126China College of Physics and Electronic Engineering State Key Laboratory of Quantum Optics and Quantum Optics DevicesShanxi UniversityTaiyuan030006China

Addressing the challenges posed by the nonlinear and non-stationary vibrations in rotating machinery,where weak fault characteristic signals hinder accurate fault state representation,we propose a novel feature extraction method that combines the Flexible Analytic Wavelet Transform(FAWT)with Nonlinear Quantum Permutation ***,leveraging fractional orders and arbitrary scaling and translation factors,exhibits superior translational invariance and adjustable fundamental oscillatory *** flexibility enables FAWT to provide well-suited wavelet shapes,effectively matching subtle fault components and avoiding performance degradation associated with fixed frequency partitioning and low-oscillation bases in detecting weak *** our approach,gearbox vibration signals undergo FAWT to obtain *** theory is then introduced into permutation entropy to propose Nonlinear Quantum Permutation Entropy,a feature that more accurately characterizes the operational state of vibration simulation *** nonlinear quantum permutation entropy extracted from sub-bands is utilized to characterize the operating state of rotating machinery.A comprehensive analysis of vibration signals from rolling bearings and gearboxes validates the feasibility of the proposed *** assessments with parameters derived from traditional permutation entropy,sample entropy,wavelet transform(WT),and empirical mode decomposition(EMD)underscore the superior effectiveness of this approach in fault detection and classification for rotating machinery.

关键词： Rotating machinery quantum theory nonlinear quantum permutation entropy Flexible Analytic Wavelet Transform(FAWT) feature extraction

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：