检索结果-南通市图书馆

An analytical analysis for the mechanical performance of fully-grouted rockbolts based on the exponential softening model

在线全文

学校读者我要写书评

暂无评论

International Journal of Mining Science and Technology 2022年第5期32卷 981-995页

作者： Zhongwen Yue Akang Li Peng WANG Peng WANG Department of Mechanics and Civil Engineering China University of Mining and Technology-BeijingBeijing 100083China Pan-China Construction Group Co. Ltd.Beijing 100070China

This paper presented a novel bond-slip model to better reveal the mechanical behavior of the bolt-grout interface for fully-grouted rockbolts under tensile loads by considering the non-linear response in the softening stage.The exponential decay function is adopted for describing the non-linear response in the softening stage.Based on the improved bond-slip model,the corresponding analytical solutions for the interfacial shear stress and the axial force of the bolt under different loading stages are solved.Then,the validity of this proposed model was verified by comparing with the experimental results.The results show that compared with the linear softening model,the proposed model is more suitable for predicting the mechanical performance of fully-grouted rockbolts.Finally,a series of parametric studies are conducted to explore the effect of model parameters on the mechanical properties of fully-grouted rockbolts.The results indicate that compared with the anchor length,the bolt diameter and the bond strength of the bolt-grout interface have a significance influence on the ultimate load of bolt,especially for the elastic and softening stage.Moreover,it can be found that using the linear softening model maybe overestimates the supporting performance of grouted bolt,resulting in an unsafe design for bolt.

关键词： Fully-grouted rockbolts Non-linear response Bond-slip model Anchor length Analytical solutions

Partial Correlation Analysis Based Identification of Distribution Network Topology

在线全文

学校读者我要写书评

暂无评论

CSEE Journal of Power and Energy Systems 2023年第4期9卷 1493-1504页

作者： Yanli Liu Peng WANG School of electrical and information engineering Tianjin UniversityTianjin300072China

Accurately identifying distribution network topol-ogy,which tends to be a mesh configuration with increasing penetration rate of distributed energy resources(DERs),is critical for reliable operation of a smart distribution network.Multicollinearity among node voltages makes existing topology identification methods unstable and inaccurate.Considering partial correlation analysis can reveal the intrinsic correlation of two variables by eliminating the influence of other variables,this paper develops a novel data-driven method based on partial correlation analysis to identify distribution network topology(radial,mesh,or including DERs)using only historical voltage amplitude data.First,maximum spanning tree of network is generated through Prim algorithm.Then,the loops of network are identified by taking tree neighbors as controlling variables in partial correlation analysis.Finally,a new topology verification mechanism based on partial correlation analysis is developed to correct wrong connections caused by multicollinearity.Test results on IEEE 33-node system,IEEE 123-node system and practical distribution network demonstrate that our method outperforms common data-driven methods,and can robustly identify both radial and mesh distribution network with DERs.IndexTerms-Data-driven,linear correlation,partial correlation,smart meter,topology identification.

关键词： Data-driven linear correlation partial correlation smart meter topology identification.

Fatigue cracking criterion of high-strength steels induced by inclusions under high-cycle fatigue

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

Journal of Materials Science & Technology 2023年第23期154卷 114-128页

作者： Peng WANG peng Zhang Bin wang Yankun Zhu Zikuan Xu Zhefeng Zhang Shi-changxu Innovation Center for Advanced Materials Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China School of Materials Science and Engineering University of Science and Technology of China Shenyang 110016 China

Fatigue properties of high-strength steels become more and more sensitive to inclusions with enhancing the ultimate tensile strength (UTS) because the inclusions often cause a relatively low fatigue strength and a large scatter of fatigue lives. In this work, four S–N curves and more than 200 fatigue fracture morphologies were comprehensively investigated with a special focus on the size and type of inclusions at the fatigue cracking origin in GCr15 steel with a wide strength range by different heat treatments after high-cycle fatigue (HCF). It is found that the percentage of fatigue failure induced by the inclusion including Al2 O3 and TiN gradually increases with increasing the UTS, while the percentage of failure at sample surfaces decreases conversely and the fatigue strength first increases and then decreases. Besides, it is interestingly noted that the inclusion sizes at the cracking origin for TiN are smaller than that for Al2 O3 because the stress concentration factor for TiN is larger than that for Al2 O3 based on the finite element simulation. For the first time, a new fatigue cracking criterion including the isometric inclusion size line in the strength-toughness coordinate system with specific physical meaning was established to reveal the relationship among the UTS, fracture toughness, and the critical inclusion size considering different types of inclusions based on the fracture mechanics. And the critical inclusion size of Al2 O3 is about 1.33 times of TiN. The fatigue cracking criterion could be used to judge whether fatigue fracture occurred at inclusions or not and provides a theoretical basis for controlling the scale of different inclusion types for high-strength steels. Our work may offer a new perspective on the critical inclusion size in terms of the inclusion types, which is of scientific interest and has great merit to industrial metallurgical control for anti-fatigue design.

关键词： High-strength steel High-cycle fatigue Critical inclusion size Inclusion types Tensile strength Fracture toughness Fatigue cracking criterion

Improving tree health assessment accuracy at low temperatures:considering the effect of trunk ice content on electrical resistance and stress wave tomography

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

林业研究:英文版 2023年第5期34卷 1503-1510页

作者： Jiaxing Guo Peng WANG Yuting wang Huadong Xu College of Engineering and Technology Northeast Forestry UniversityHarbin 150040People’s Republic of China Forest Science Research Institute of Tibet Municipality Lhasa 850000People’s Republic of China

Accurate decay detection and health assessment of trees at low temperatures is an important issue for forest management and ecology in cold areas.Low temperature ice formation on tree health assessment is unknown.Because electric resistance tomography and stress wave tomography are two widely used methods for the detection of tree decay,this study investigated the effect of ice content on trunk electrical resistance and stress wave velocity to improve tree health assessment accuracy.Moisture content,trunk electrical resistance and stress wave velocity using time domain reflectometry were carried out on Larix gmelinii and Populus simonii.Ice content is based on moisture content data.The ice content of both species showed a trend of increasing and then decreasing.This was opposite with ambient temperatures.With the decrease of temperatures,daily average ice content increased,but the range narrowed gradually and both electrical resistance and stress wave velocity increased.Both increased rapidly near 0℃,mainly caused by ice formation(phase change and freezing of free water)in live trees.In addition,both are positively correlated with ice content.The results suggest that ice content should be considered for improving the accuracy of tree decay detection and health evaluation using electric resistance tomography and stress wave velocity methods under low temperatures.

关键词： Cross-section electrical resistance Cross-section stress wave velocity Ambient temperatures Ice content Wood decay detection Tree heath

Tumor organoids for cancer research and personalized medicine

在线全文

学校读者我要写书评

暂无评论

Cancer Biology & Medicine 2022年第3期19卷 319-332页

作者： Hui Yang Yinuo wang Peng WANG Ning Zhang pengyuan wang Translational Cancer Research Center Peking University First HospitalBeijing 100034China Division of General Surgery Peking University First HospitalBeijing 100034China

Organoids are three-dimensional culture systems generated from embryonic stem cells,induced pluripotent stem cells,and adult stem cells.They are capable of cell proliferation,differentiation,and self-renewal.Upon stimulation by signal factors and/or growth factors,organoids self-assemble to replicate the morphological and structural characteristics of the corresponding organs.They provide an extraordinary platform for investigating organ development and mimicking pathological processes.Organoid biobanks derived from a wide range of carcinomas have been established to represent different lesions or stages of clinical tumors.Importantly,genomic and transcriptomic analyses have confirmed maintenance of intra-and interpatient heterogeneities in organoids.Therefore,this technology has the potential to revolutionize drug screening and personalized medicine.In this review,we summarized the characteristics and applications of organoids in cancer research by the establishment of organoid biobanks directly from tumor organoids or from genetically modified non-cancerous organoids.We also analyzed the current state of organoid applications in drug screening and personalized medicine.

关键词： Organoids cancer research heterogeneity personalized medicine clinical cancer therapy

Underwater Directional Acoustic Source Based on Pentamode Material

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2024年第1期37卷 1-9页

作者： Binghao Zhao Peng WANG Dongwei wang Gengkai Hu School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Wuhan Second Ship Design and Research Institute Wuhan 430205China

An underwater directional acoustic emitter is conceived with a highly anisotropic lattice material,whose acoustic characteristics manifest strong dependence on the orientation of the lattice material’s principal axis.Exploiting these features,a cylindrical structure made of such anisotropic lattice material is engineered to possess distinct impedance values in different directions,thereby facilitating wave emission along the principal axis while inducing reflection in other directions.Notably,through numerical simulations,it is demonstrated that the emission direction can be effectively manipulated by adjusting the principal axis orientation,concurrently enhancing the emitted power.In contrast to previous directional acoustic structures,the compact emitter presented in this study can get rid of the size-wavelength constraint,enabling effective control of low-frequency waves.

关键词： Underwater Directional emission Pentamode material Broadband frequency

Coverage control for mobile sensor networks with unknown terrain roughness and nonuniform time-varying communication delays

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

Science China(Information Sciences) 2023年第12期66卷 80-93页

作者： Peng WANG Cheng SONG Lu LIU Department of Biomedical Engineering City University of Hong Kong School of Automation Nanjing University of Science and Technology City University of Hong Kong Chengdu Research Institute

This paper investigates the coverage control problem on a circle with unknown terrain roughness and nonuniform time-varying communication delays. Adaptive coverage control laws are proposed for mobile sensors to collaboratively estimate the unknown roughness function using the basis function approximation approach. Moreover, contrary to existing studies, nonuniform time-varying communication delays are considered in this paper. Under the proposed adaptive coverage control laws, the sensor network can be driven to its optimal configuration minimizing the coverage cost function in the presence of nonuniform communication delays, and each sensor can learn the true roughness function. Finally, a simulation example is provided to show the effectiveness of the proposed control laws.

关键词： multi-agent systems cooperative control adaptive control cost function time-varying communication delays

Effective norfloxacin elimination via photo-Fenton process over the MIL-101(Fe)-NH_(2)immobilized onα-Al_(2)O_(3)sheet

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2022年第11期33卷 4828-4833页

作者： Qian Zhao Chong-Chen wang Peng WANG Beijing Key Laboratory of Functional Materials for Building Structure and Environment Remediation/Beijing Energy Conservation&Sustainable Urban and Rural Development Provincial and Ministry Co-construction Collaboration Innovation Center School of Environment and Energy EngineeringBeijing University of Civil Engineering and ArchitectureBeijing 100044China

MIL-101(Fe)-NH_(2)@Al_(2)O_(3)(MA)catalysts were successfully synthesized by reactive seeding(RS)method onα-Al_(2)O_(3)substrate,which demonstrated excellent photo-Fenton degradation performance toward fluoroquinolone antibiotics(i.e.,norfloxacin,ciprofloxacin,and enrofloxacin).The structure and morphology of the obtained MA were characterized by transmission electron microscopy(TEM),high-resolution transmission electron microscopy(HRTEM),atomic force microscope(AFM).The as-prepared MA could accomplish>90%of norfloxacin degradation efficiency for 10 cycles’photo-Fenton processes,owing to its excellent chemical and water stability.In addition,the effects of operational factors including H_(2)O_(2)concentration,foreign ions,and pH on the photo-Fenton degradation of norfloxacin over MA were clarified.The ESR spectra further document that^(•)O_(2)^(−),1O_(2)and•OH radicals are prominent in the decomposition process of antibiotic molecules.Finally,the plausible photo-Fenton norfloxacin degradation mechanisms were proposed and verified.

关键词： MIL-101(Fe)-NH_(2)@Al_(2)O_(3)(MA) Photo-Fenton NOR Mechanism Real solar

Recent advances in chemical durability and mechanical stability of superhydrophobic materials: Multi-strategy design and strengthening

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2022年第34期129卷 40-69页

作者： Peng WANG Changyang Li Dun Zhang Key Laboratory of Marine Environmental Corrosion and Bio-fouling Institute of OceanologyChinese Academy of SciencesQingdao 266071China University of Chinese Academy of Sciences Beijing 100039China Center for Ocean Mega-Science Chinese Academy of SciencesQingdao 266071China Open Studio for Marine Corrosion and Protection Pilot National Laboratory for Marine Science and TechnologyQingdao 266237China

Inspired by the lotus leaf effect, non-wetting artificial superhydrophobic surfaces demonstrate an enormous potential in numerous fields. However, limited by poor stability and durability, superhydrophobic surfaces are rarely available for practical applications. In this review, based on the wettability mechanisms and failure modes of superhydrophobic surfaces, it is proposed that the construction of highly stable superhydrophobic materials can be approached from four aspects, including structural design, chemical bonding, interfacial-strengthening of hydrophobic materials and substrates, and self-healing. We introduced in detail the design ideas, strengthening approaches, and characterization tools of highly stable superhydrophobic materials from the perspective of multi-strategy design and strengthening, and provided corresponding insights. Eventually, the development, current status, and prospects of highly stable and multifunctional superhydrophobic materials were also presented in detail. Recent advances and development prospects of durable superhydrophobic materials were summarized and discussed in this review,providing certain insights and design guidelines for the fabrication of stable superhydrophobic materials.

关键词： Superhydrophobicity Stability Durability Strengthening