检索结果-南通市图书馆

Dynamic response of buildings under debris flow impact

Journal of Mountain Science 2024年第5期21卷 1581-1597页

作者： LIU Huan FAN Xiaoyi tian Shujun DENG Xin School of Mechanical and Electrical Engineering Southwest Petroleum UniversityChengdu 610500China School of Civil Engineering and Geomatics Southwest Petroleum UniversityChengdu 610500China Housing and Urban-Rural Development Bureau of Mingshan District Ya’an 625100China Engineering Safety Assessment and Protection Research Southwest Petroleum UniversityChengdu 610500China School of Civil Engineering and Architecture Southwest University of Science and TechnologyMianyang 621010China

This study employs the smoothed particle hydrodynamics–finite element method(SPH–FEM) coupling numerical method to investigate the impact of debris flow on reinforced concrete(RC)-frame buildings. The methodology considers the variables of debris flow depth and velocity and introduces the intensity index IDV(IDV = DV) to evaluate three different levels of debris flow impact intensity. The primary focus of this study is to investigate the dynamic response and failure mechanism of RC-frame buildings under debris flow impact, including structural failure patterns, impact force and column displacement. The results show that under a highintensity impact, a gradual collapse process of the RCframe building can be observed, and the damage mode of the frame column reflects shear failure or plastic hinge failure mechanism. First, the longitudinal infill walls are damaged owing to their low out-of-plane flexural capacity;the critical failure intensity index IDV value is approximately 7.5 m2/s. The structure cannot withstand debris flows with an intensity index IDV greater than 16 m2/s, and it is recommended that the peak impact force should not exceed 2100 k N. The impact damage ability of debris flow on buildings mostly originates from the impact force of the frontal debris flow, with the impact force of the debris flow body being approximately 42% lower than that of the debris flow head. Finally, a five-level classification system for evaluating the damage status of buildings is proposed based on the numerical simulation and investigation results of the disaster site.

关键词： SPH–FEM method Debris flow Buildings The intensity index Dynamic response

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

Modeling and analysis for material removal and surface roughness in fluid jet polishing of optical glass

引用

Friction 2024年第7期12卷 1548-1563页

作者： Zhongchen CAO Ming WANG Haitao LIU tian HUANG Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education Tianjin UniversityTianjin 300072China School of Engineering The University of WarwickCoventry CV47ALUK

luid jet polishing(FJP)is a non-contact polishing technology that can fabricate free-form optical surfaces with sub-micron-level form accuracy and nano-level surface roughness,especially for hard and brittle *** surface generation model of FJP can be used to guide the determination and optimization of process parameters and is of great significance for understanding the evolution mechanism of surface ***,predictive models for the microscopic topography of polished surfaces are still *** study established a macroscopic surface profile model for predicting 3D material removal characteristics and surface texture by combining the 3D computer fluid dynamics(CFD)simulation model and single-particle erosion mechanism.A fractal theory-based erosion model has been built to calculate the material removal caused by the erosion of a single abrasive particle on the rough surface;thus,it predicts the micro-topography and surface roughness of the polished samples.A series of polishing experiments were conducted to analyze the feasibility and accuracy of the model quantitatively and study the influence mechanism of process parameters on the material removal characteristics and surface *** indicated that the models could well predict material removal and surface *** prediction accuracy of the surface roughness Ra and maximum removal depth is better than 91.6%and 90%,*** is also found that the material removal rate of FJP could reach 0.517 mm3/min,and the surface roughness convergence rate could reach 62.9%.

关键词： fluid jet polishing(FJP) computational fluid dynamics(CFD) material removal mechanism surface roughness theoretical model

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

Associative Tasks Computing Offloading Scheme in Internet of Medical Things with Deep Reinforcement Learning

引用

China Communications 2024年第4期21卷 38-52页

作者： Jiang Fan Qin Junwei Liu Lei tian Hui School of Communications and Information Engineering Xi’an University of Posts and TelecommunicationsXi’an 710121China State Key Laboratory of Networking and Switching Technology Beijing University of Posts and TelecommunicationsBeijing 100876China

The Internet of Medical Things(Io MT) is regarded as a critical technology for intelligent healthcare in the foreseeable 6G era. Nevertheless, due to the limited computing power capability of edge devices and task-related coupling relationships, Io MT faces unprecedented challenges. Considering the associative connections among tasks, this paper proposes a computing offloading policy for multiple-user devices(UDs) considering device-to-device(D2D) communication and a multi-access edge computing(MEC)technique under the scenario of Io MT. Specifically,to minimize the total delay and energy consumption concerning the requirement of Io MT, we first analyze and model the detailed local execution, MEC execution, D2D execution, and associated tasks offloading exchange model. Consequently, the associated tasks’ offloading scheme of multi-UDs is formulated as a mixed-integer nonconvex optimization problem. Considering the advantages of deep reinforcement learning(DRL) in processing tasks related to coupling relationships, a Double DQN based associative tasks computing offloading(DDATO) algorithm is then proposed to obtain the optimal solution, which can make the best offloading decision under the condition that tasks of UDs are associative. Furthermore, to reduce the complexity of the DDATO algorithm, the cacheaided procedure is intentionally introduced before the data training process. This avoids redundant offloading and computing procedures concerning tasks that previously have already been cached by other UDs. In addition, we use a dynamic ε-greedy strategy in the action selection section of the algorithm, thus preventing the algorithm from falling into a locally optimal solution. Simulation results demonstrate that compared with other existing methods for associative task models concerning different structures in the Io MT network, the proposed algorithm can lower the total cost more effectively and efficiently while also providing a tradeoff between delay and energy co

关键词： associative tasks cache-aided procedure double deep Q-network Internet of Medical Things(IoMT) multi-access edge computing(MEC)

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

Hydration lubrication modulated by water structure at TiO2–aqueous interfaces

引用

Friction 2024年第4期12卷 591-605页

作者： Pingsu MA Yuan LIU Ke HAN Yu tian Liran MA State Key Laboratory of Tribology in Advanced Equipment Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China

The nature of solid-liquid interfaces is of great significance in *** advances have been made in lubrication based on hydration ***,a detailed molecular-level understanding is still ***,we investigated water molecule behaviors at the TiO2-aqueous interfaces by the sum-frequency generation vibrational spectroscopy(SFG-VS)and atomic force microscope(AFM)to elucidate the fundamental role of solid-liquid interfaces in *** contributions of water structures and hydration effects were revealed,where water structures played the dominant role in lubrication for TiO2 surfaces of varying hydrophilicity,while hydration effects dominated with the increasing of ion *** lubrication is observed on the initial TiO2 surfaces with strongly H-bonded water molecules compared to the hydrophilic TiO2 surfaces with more disordered *** stable ordered water arrangement with strong hydrogen bonds and the shear plane occurring between the ordered water layer and subsequent water layer may play a significant role in achieving lower *** adsorbed hydrated molecules with the increasing ionic concentration perturb ordered water but lead to the enhancement of hydration effects,which is the main reason for the improved lubrication for both *** work provides more insights into the detailed molecular-level understanding of the mechanism of hydration lubrication.

关键词： hydration lubrication interfacial water structures hydration effects titanium dioxide(TiO2)

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

Analyzing topics in social media for improving digital twinning based product development

引用

Digital Communications and Networks 2024年第2期10卷 273-281页

作者： Wenyi Tang Ling tian Xu Zheng Ke Yan School of Computer Science and Engineering University of Electronic Science and Technology of ChinaChengdu611731China

Digital twinning enables manufacturers to create digital representations of physical entities,thus implementing virtual simulations for product *** efforts of digital twinning neglect the decisive consumer feedback in product development stages,failing to cover the gap between physical and digital *** work mines real-world consumer feedbacks through social media topics,which is significant to product *** specifically analyze the prevalent time of a product topic,giving an insight into both consumer attention and the widely-discussed time of a *** primary body of current studies regards the prevalent time prediction as an accompanying task or assumes the existence of a preset ***,these proposed solutions are either biased in focused objectives and underlying patterns or weak in the capability of generalization towards diverse *** this end,this work combines deep learning and survival analysis to predict the prevalent time of *** propose a specialized deep survival model which consists of two *** first module enriches input covariates by incorporating latent features of the time-varying text,and the second module fully captures the temporal pattern of a rumor by a recurrent network ***,a specific loss function different from regular survival models is proposed to achieve a more reasonable *** experiments on real-world datasets demonstrate that our model significantly outperforms the state-of-the-art methods.

关键词： Digital twinning Product development Topic analysis Social media

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

Non-Targeted Metabolomics Reveals the Metabolic Alterations in Response to Artificial Selective Breeding in the Fast-Growing Strains of Pacific Oyster

引用

Journal of Ocean University of China 2024年第2期23卷 518-528页

作者： HU Boyang tian Yuan LIU Shikai LI Qi Key Laboratory of Mariculture Ministry of EducationOcean University of ChinaQingdao 266003China Laboratory for Marine Fisheries Science and Food Production Processes Laoshan LaboratoryQingdao 266237China

Pacific oyster(Crassostrea gigas)is one of the most important mollusks cultured all around the *** breeding programs of Pacific oysters in China is initiated since 2006 and developed the genetically improved strain with fast-growing ***,little is known about the metabolic signatures of the fast-growing *** the present study,the non-targeted metabolomics was performed to analyze the metabolic signatures of adductor muscle tissue in one-year old Pacific oysters from fast-growing strain and the wild population.A total of 7767 and 10174 valid peaks were extracted and quantified in ESI^(+)and ESI^(−)modes,resulting in 399 and 381 annotated metabolites,*** and OPLS-DA revealed that considerable separation among samples from fastgrowing strain and wild population,suggesting the differences in metabolic ***,81 significantly different metabolites(SDMs)were identified in the comparisons between fast-growing strain and wild population,based on the strict *** was found that there were highly correlation and conserved coordination among these *** enrichment analysis indicated that the SDMs were tightly related to pantothenate and CoA biosynthesis,steroid hormone biosynthesis,riboflavin metabolism,and arginine and proline *** them,the CoA biosynthesis and metabolism,affected by pantetheine and pantothenic acid,might be important for the growth of Pacific oysters under artificial selective *** study provides the comprehensive views of metabolic signatures in response to artificially selective breeding,and is helpful to better understand the molecular mechanism of fastgrowing traits in Pacific oysters.

关键词： metabolic signature Pacific oyster artificial selection fast-growing trait

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

Constructing oxygen deficiency-rich V_(2)O_(3)@PEDOT cathode for high-performance aqueous zinc-ion batteries

引用

Rare Metals 2024年第2期43卷 635-646页

作者： Dong-Fei Sun Zi-Juan Wang tian tian Xin Yu Dan-Dan Yu Xiao-Zhong Zhou Guo-Fu Ma Zi-Qiang Lei Key Laboratory of Eco-functional Polymer Materials of the Ministry of Education Key Laboratory of Eco-environmental Polymer Materials of Gansu ProvinceSchool of College of Chemistry and Chemical EngineeringNorthwest Normal UniversityLanzhou730070China

Aqueous zinc-ion batteries(AZIBs)have attracted widespread attention due to the advantages of high safety and environmental *** V_(2)O_(3) is a promising cathode,the strong electrostatic interaction between Zn^(2+) and V_(2)O_(3) crystal,and the sluggish reaction kinetics still limit their application in ***,the oxygen defects rich V_(2)O_(3) with conducive poly(3,4-ethylenedioxythiophene)(PEDOT)shell(V_(2)O_(3)-Od@PEDOT)was fabricated for AZIBs by combining the sulfur-assisted thermal reduction and in-situ polymerization *** introduced oxygen vacancies of V_(2)O_(3)–Od@PEDOT weaken the electrostatic interaction between Zn^(2+) and the host material,improving the interfacial electron transport,while the PEDOT coating enhances the structural stability and conductivity of V_(2)O_(3),thus accelerating the reaction *** on the advantages,V_(2)O_(3)–Od@PEDOT electrode delivers a reversible capacity of 495 mAh·g^(−1) at 0.1 A·g^(−1),good rate capability(189 mAh·g^(−1)at 8.0 A·g^(−1)),and an impressive cycling stability with 90.1%capacity retention over 1000 cycles at 8.0 A·g^(−1).The strategy may provide a path for exploiting the other materials for high performance AZIBs.

关键词： Oxygen defects V_(2)O_(3) PEDOT Electrochemical self-optimization Aqueous zinc-ion batteries

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

Revealing the anti-sintering phenomenon on silica-supported nickel catalysts during CO_(2)hydrogenation

引用

Journal of Environmental Sciences 2024年第6期140卷 270-278页

作者： Liuqingqing Yang tiancheng Pu Feixiang tian Yulian He Minghui Zhu State Key Laboratory of Chemical Engineering School of Chemical EngineeringEast China University of Science and TechnologyShanghai 200237China University of Michigan-Shanghai Jiao Tong University Joint Institute Shanghai Jiao Tong UniversityShanghai 200240China School of Chemistry and Chemical Engineering Shanghai Jiao Tong UniversityShanghai 200240China

The CO_(2)catalytic hydrogenation represents a promising approach for gas-phase CO_(2)utilization in a direct *** to its excellent hydrogenation ability,nickel has been widely studied and has shown good activities in CO_(2)hydrogenation reactions,in addition to its high availability and low ***,Ni-based catalysts are prone to sintering under elevated temperatures,leading to unstable catalytic *** the present study,various characterization techniques were employed to study the structural evolution of Ni/SiO_(2)during CO_(2)*** anti-sintering phenomenon is observed for both 9%Ni/SiO_(2)and 1%Ni/SiO_(2)during CO_(2)hydrogenation at 400℃.Results revealed that Ni species were re-dispersed into smaller-sized nanoparticles and formed Ni^(0)active *** interestingly,this anti-sintering phenomenon leads to distinct outcomes for two catalysts,with a gradual increase in both reactivity and CH_(4)selectivity for 9%Ni/SiO_(2)presumably due to the formation of abundant surface Ni°from redispersion,while an apparent decreasing trend of CH_(4)selectivity for 1%Ni/SiO_(2)sample,presumably due to the formation of ultra-small nanoparticles that diffuse and partially filled the mesoporous pores of the silica support over ***,the redispersion phenomenon was found relevant to the H_(2)gas in the reaction environment and enhanced as the H_(2)concentration *** finding is believed to provide in-depth insights into the structural evolution of Ni-based catalysts and product selectivity control in CO_(2)hydrogenation reactions.

关键词： Carbon dioxide utilization CO_(2)hydrogenation Nickel-based catalysts Anti-sintering Structural evolution

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

Effect of streamlined nose length on aerodynamic performance of high-speed train with a speed of 400 km/h

引用

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第7期25卷 525-540页

作者： Nianxun LI tian LI Zhiyuan DAI Deng QIN Jiye ZHANG State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong UniversityChengdu 610031China

The streamlined nose length(SNL)plays a crucial role in determining the aerodynamic performance of high-speed *** appropriate SNL can not only effectively reduce the magnitude of aerodynamic drag and lift forces,but also improve the performance of the high-speed train in tunnel passing and crosswind *** this study,a numerical simulation of the aerodynamic performance of high-speed trains at a speed of 400 km/h,with varying SNLs,is conducted using the k-ωshear stress transport(SST)turbulence *** different SNLs include 6.0,7.0,8.0,9.0,9.8,12.0,15.0,and 18.0 *** order to validate the accuracy of the numerical simulation,its results are compared with wind tunnel test data obtained from the *** simulation is carried out using compressible and incompressible gases to determine the effect of gas compressibility on *** impact of SNL on the aerodynamic performance of the trains is analyzed in terms of aerodynamic forces,velocity,and pressure *** comparison to the original train,the train with a 6.0 m SNL experienced a 10.8%increase in overall aerodynamic ***,the lift forces on the head and tail cars increased by 35.7%and 75.5%,*** the other hand,the train with an 18.0 m SNL exhibited a 16.5%decrease in aerodynamic ***,the lift forces on the head and tail cars decreased by 21.9%and 49.7%,*** aerodynamic drag force of the entire train varies linearly with the SNL,while the aerodynamic lift of the tail car follows a quadratic function in relation to the SNL.

关键词： Streamlined nose length(SNL) High-speed train Aerodynamic performance Numerical simulation Flow structures

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

Flame Synthesis of Zr/ZSM-5 Catalysts with Tunable Acidity for the Oxidative Dehydrogenation of Propane to Propene

引用

Journal of Thermal Science 2024年第1期33卷 268-283页

作者： DANIEL Samuel FONZEU MONGUEN Cedric Karel WU Lingnan tian Zhenyu Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Tuning the surface acidity of ZSM-5 catalyst is essential to achieve desired propene selectivity and *** several ratios of Zr were utilized to modify ZSM-5 via flame spray pyrolysis technique coupled with a pulse spray evaporation *** interaction between Zr and ZSM-5 in the flame influenced the physicochemical and acidity properties of the Zr/*** increasing Zr ratio in ZSM-5 shows coated layers of irregular nano-sized Zr with an increase in crystallite sizes due to the synergetic effect between Zr and *** surface chemical analysis revealed increased lattice oxygen on the Zr modified ZSM-5(1:4) sample compared to other *** acidity analysis revealed the Lewis and Br?nsted acid distribution in the weak and medium acid sites on the catalyst ***,the increase in Zr loading decreased the concentration of Br?nsted acid sites and tuned the catalyst surface to more Lewis acidity,promoting propene selectivity and hindering the over-oxidation of *** modified ZSM-5 catalysts were examined in a fixed bed reactor within 300℃-700℃ at a gas hourly space velocity(GHSV) of 6000 mL·g(catalysts)^(-1)·h^(-1) for the oxidative dehydrogenation of propane(ODHP) to *** the catalysts,Zr/ZSM-5(1:4) exhibited the best propene yield, with 57.19% propane conversion and 75.54% selectivity to propene and the highest *** work provides a promising strategy for tuning the surface acidity of ZSM-5 with Zr for ODHP applications.

关键词： flame synthesis Zr modified ZSM-5 catalyst ODHP surface acidity lattice oxygen

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

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：