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Buckling Properties of Water-Drop-Shaped Pressure Hulls with Various Shape Indices Under Hydrostatic External Pressure

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China Ocean engineering 2024年第1期38卷 1-17页

作者： DING Xiao-de ZHANG Jian WANG Fang JIAO Hui-feng WANG Ming-lu School of Mechanical engineering Jiangsu University of Science and TechnologyZhenjiang 212003China Shanghai engineering research center of Marine Renewable Energy College of Engineering Science and Technol-ogyShanghai Ocean UniversityShanghai 201306China China Ship Scientific research center Wuxi 214082China

The water-drop-shaped pressure hull has a good streamline,which has good application prospect in the underwater ***,this study conducted analytical,experimental and numerical investigation of the buckling properties of water-drop-shaped pressure hulls under hydrostatic pressure.A water-drop experiment was conducted to design water-drop-shaped pressure hulls with various shape *** critical loads for the water-drop-shaped pressure hulls were resolved by using Mushtari’s *** numerical simulations including linear buckling analysis and nonlinear buckling analysis including eigenmode imperfections were *** results indicated that the critical loads resolved by Mushtari's formula were in good agreement with the linear buckling loads from the numerical *** formula can be extended to estimate the buckling capacity of water-drop-shaped pressure *** addition,three groups of pressure hulls were fabricated by using stereolithography,a rapid prototyping ***,three groups of the pressure hulls were subjected to ultrasonic measurements,optical scanning,hydrostatic testing and numerical *** experimental results were consistent with the numerical *** results indicate that the sharp end of the water-drop-shaped pressure hulls exhibited instability compared with the blunt *** paper provides a new solution to the limitations of experimental studies on the water-drop-shaped pressure hulls as well as a new configuration and evaluation method for underwater observatories.

关键词： buckling pressure hull water drop underwater observatory

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Progress in the application of polymer fibers in solid electrolytes for lithium metal batteries

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Journal of Energy Chemistry 2024年第5期92卷 26-42页

作者： Junbao Kang Nanping Deng Bowen Cheng Weimin Kang State Key Laboratory of Separation Membranes and Membrane Processes/national center for International Joint research on Separation Membranes School of Textile Science and EngineeringTiangong UniversityTianjin 300387China

Solid state lithium metal batteries(SSLMBs)are considered to be one of the most promising battery systems for achieving high energy density and excellent safety for energy storage in the ***,current existed solid-state electrolytes(SSEs)are still difficult to meet the practical application requirements of *** this review,based on the analysis of main problems and challenges faced by the development of SSEs,the ingenious application and latest progresses including specific suggestions of various polymer fibers and their membrane products in solving these issues are emphatically ***,the inherent defects of inorganic and organic electrolytes are pointed ***,the application strategies of polymer fibers/fiber membranes in strengthening strength,reducing thickness,enhancing thermal stability,increasing the film formability,improving ion conductivity and optimizing interface stability are discussed in detail from two aspects of improving physical structure properties and electrochemical ***,the researches and development trends of the intelligent applications of high-performance polymer fibers in SSEs is *** review intends to provide timely and important guidance for the design and development of polymer fiber composite SSEs for SSLMBs.

关键词： Composite solide lectrolytes Polymer fibers Solid-state lithium metal batteries Solid-stateel ectrolytes Nanofiber membranes

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Modeling analysis of cobalt-based Fischer-Tropsch catalyst particles

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Chinese Journal of Chemical engineering 2024年第6期70卷 82-92页

作者： Huashuai Wu Gang Wang Yong Yang Yongwang Li College of Chemical engineering and Technology Taiyuan University of TechnologyTaiyuan 030024China national Energy research&Development center for Coal to Liquid Fuels Synfuels China CompanyLimitedBeijing 101400China

The influences of particle size,shape,and catalyst distribution on the reactivity and hydrocarbon product selectivity of a cobalt-based catalyst for Fischer-Tropsch synthesis were investigated in the present work.A self-consistent kinetic model for Fischer-Tropsch reaction proposed here was found to correlate experimental data well and hence was used to describe the consumption rates of reactants and formation rates of hydrocarbon *** perturbed-chain statistical associating fluid theory equation of state was used to describe vapor-liquid equilibrium behavior associated with Fischer-Tropsch *** interaction between intraparticle diffusion and Fischer-Tropsch reaction was investigated in *** showed that in order to avoid the adverse influence of intraparticle diffusional limitations on catalyst reactivity and product selectivity,the use of small particles is *** eggshell spherical particles are shown to keep the original catalyst reactivity and enhance the selectivity of heavy hydrocarbon *** suitable layer thickness for a spherical particle with a diameter of 2 mm is nearly 0.15 *** the same outer diameter of 2 mm,the catalyst reactivity and heavy product selectivity of hollow cylindrical particles with a layer thickness of 0.25 mm are found to be larger than eggshell spherical *** the viewpoint of catalytic performance,hollow cylindrical particles are a better choice for industrial applications.

关键词： Fischer-Tropsch synthesis Kinetic modeling Vapor-liquid equilibria Numerical simulation Intraparticle diffusion Particle shapes

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Transparent and Accountable Training data Sharing in Decentralized Machine Learning Systems

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Computers, Materials & Continua 2024年第6期79卷 3805-3826页

作者： Siwan Noh Kyung-Hyune Rhee Industrial Science Technology research center Pukyong National UniversityBusan48513South Korea Division of Computer engineering Pukyong National UniversityBusan48513South Korea

In Decentralized Machine Learning(DML)systems,system participants contribute their resources to assist others in developing machine learning *** malicious contributions in DML systems is challenging,which has led to the exploration of blockchain *** leverages its transparency and immutability to record the provenance and reliability of training ***,storing massive datasets or implementing model evaluation processes on smart contracts incurs high computational ***,current research on preventing malicious contributions in DML systems primarily focuses on protecting models from being exploited by workers who contribute incorrect or misleading ***,less attention has been paid to the scenario where malicious requesters intentionally manipulate test data during evaluation to gain an unfair *** paper proposes a transparent and accountable training data sharing method that securely shares data among potentially malicious system ***,we introduce a blockchain-based DML system architecture that supports secure training data sharing through the IPFS ***,we design a blockchain smart contract to transparently split training datasets into training and test datasets,respectively,without involving system *** the system,transparent and accountable training data sharing can be achieved with attribute-based proxy *** demonstrate the security analysis for the system,and conduct experiments on the Ethereum and IPFS platforms to show the feasibility and practicality of the system.

关键词： Decentralized machine learning data accountability dataset sharing

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Numerical Simulation on Production Trials by Using Depressurization for Typical Marine Hydrate Reservoirs:Well Type and Formation Dip

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Journal of Ocean University of China 2024年第3期23卷 661-675页

作者： QIN Fanfan SUN Jiaxin GU Yuhang CAO Xinxin MAO Peixiao NING Fulong JIANG Guosheng national center for International research on Deep Earth Drilling and Resource Development Faculty of EngineeringChina University of GeosciencesWuhan 430074China Laboratory for Marine Mineral Resources Qingdao National Laboratory for Marine Science and TechnologyQingdao 266237China

Natural gas hydrate has huge reserves and is widely distributed in marine *** commercial development is of great significance for alleviating the contradiction between energy supply and *** an efficient research method,numerical simulation can provide valuable insights for the design and optimization of hydrate ***,most of the current production models simplify the reservoir as a two-dimensional(2D)horizontal layered model,often ignoring the impact of formation dip *** improve the accuracy of production prediction and provide theoretical support for the optimization of production well design,two three-dimensional(3D)geological models with different dip angles based on the geological data from two typical sites are *** vertical well,horizontal well and multilateral wells are deployed in these reservoirs with different permeabilities to perform production trial,and the sensitivity analysis of dip angles is also carried *** short-term production behaviors in high and low permeability reservoirs with different dip angles are *** simulation results show that 1)the gas and water production behaviors for different well types in the two typical reservoirs show obviously different variation laws when the short-term depressurization is conducted in the inclined formation;2)the inclined formation will reduce the gas production and increase the water extraction,and the phenomena becomes pronounced as the dip angle increases,particularly in the low-permeability reservoirs;3)and the impact of formation dip on hydrate recovery does not change significantly with the variation of well type.

关键词： natural gas hydrate inclined formation depressurization production well type

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A Novel High-Efficiency Transaction Verification Scheme for Blockchain Systems

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Computer Modeling in engineering & Sciences 2024年第5期139卷 1613-1633页

作者： Jingyu Zhang Pian Zhou Jin Wang Osama Alfarraj Saurabh Singh Min Zhu School of Computer&Communication engineering Changsha University of Science&TechnologyChangsha410015China Science and Technology on Information Systems engineering Laboratory School of Systems EngineeringNational University of Defense TechnologyChangsha410073China Computer Science Department King Saud UniversityRiyadh11437Saudi Arabia Department of Artificial Intelligence and big data Woosong UniversityDaejeon34606South Korea College of Information Science and Technology Zhejiang Shuren UniversityHangzhou310015China

Blockchain can realize the reliable storage of a large amount of data that is chronologically related and verifiable within the *** technology has been widely used and has developed rapidly in big data systems across various *** increasing number of users are participating in application systems that use blockchain as their underlying *** the number of transactions and the capital involved in blockchain grow,ensuring information security becomes *** the verification of transactional information security and privacy has emerged as a critical ***-based verification methods can effectively eliminate the need for centralized third-party ***,the efficiency of nodes in storing and verifying blockchain data faces unprecedented *** address this issue,this paper introduces an efficient verification scheme for transaction ***,it presents a node evaluation module to estimate the activity level of user nodes participating in transactions,accompanied by a probabilistic analysis for all ***,this paper optimizes the conventional transaction organization form,introduces a heterogeneous Merkle tree storage structure,and designs algorithms for constructing these heterogeneous *** analyses and simulation experiments conclusively demonstrate the superior performance of this *** verifying the same number of transactions,the heterogeneous Merkle tree transmits less data and is more efficient than traditional *** findings indicate that the heterogeneous Merkle tree structure is suitable for various blockchain applications,including the Internet of *** scheme can markedly enhance the efficiency of information verification and bolster the security of distributed systems.

关键词： Blockchain architecture transaction verification information security heterogeneous Merkle tree distributed systems

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Effects of dense planting patterns on photosynthetic traits of different vertical layers and yield of wheat under different nitrogen rates

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The Crop Journal 2024年第2期12卷 594-604页

作者： Cuicun Wang Ke Zhang Qing Liu Xiufeng Zhang Zhikuan Shi Xue Wang Caili Guo Qiang Cao Yongchao Tian Yan Zhu Xiaojun Liu Weixing Cao national engineering and Technology center for Information Agriculture Nanjing Agricultural UniversityNanjing 210095JiangsuChina MOE engineering research center of Smart Agricultural Nanjing Agricultural UniversityNanjing 210095JiangsuChina MARA Key Laboratory for Crop System analysis and Decision Making Nanjing Agricultural UniversityNanjing 210095JiangsuChina Jiangsu Key Laboratory for Information Agriculture Nanjing Agricultural UniversityNanjing 210095JiangsuChina Institute of Smart Agriculture Nanjing Agricultural UniversityNanjing 210095JiangsuChina

A two-year field experiment was conducted to measure the effects of densification methods on photosynthesis and yield of densely planted ***-plant and inter-row distances were used to define ratefixed pattern(RR)and row-fixed pattern(RS)density ***,four nitrogen(N)rates(0,144,192,and 240 kg N ha-1,termed N0,N144,N192,and N240)were applied with three densities(225,292.5,and 360×10^(4)plants ha^(-1),termed D225,D292.5,and D360).The wheat canopy was clipped into three equal vertical layers(top,middle,and bottom layers),and their chlorophyll density(Ch D)and photosynthetically active radiation interception(FIPAR)were *** showed that the response of Ch D and FIPAR to N rate,density,and pattern varied with different layers.N rate,density,and pattern had significant interaction effects on Ch *** maximum values of whole-canopy Ch D in the two seasons appeared in N240 combined with D292.5 and D360 under RR,*** two growing seasons,FIPAR values of RR were higher than those of RS by 29.37%for the top layer and 5.68%for the middle layer,while lower than those of RS by 20.62%for the bottom layer on *** a low N supply(N0),grain yield was not significantly affected by density for both *** N240,increasing density significantly increased yield under RR,but D360 of RS significantly decreased yield by 3.72%and 9.00%versus D225 in two seasons,*** an appropriate and sufficient N application,RR increased the yield of densely planted wheat more than ***,the maximum yield in two seasons appeared in the combination of D360 with N144 or N192 rather than of D225 with N240 under both patterns,suggesting that dense planting combined with an appropriate N-reduction application is feasible to increase photosynthesis capacity and yield.

关键词： Chlorophyll density Densification method Nitrogen Photosynthetically active radiation interception Wheat

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Identifying drivers of urban landuse changes in the Wenchuan earthquake- affected area by using night-time light data

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Journal of Mountain Science 2024年第4期21卷 1140-1159页

作者： HUANG Tao DING Mingtao GENG Dongxian GAO Zemin ZHENG Hao School of Civil engineering and Architecture Southwest University of Science and TechnologyMianyang 621010China Faculty of Geosciences and Environmental engineering Southwest Jiaotong UniversityChengdu 611756China analysis and Test center of Sichuan Province Chengdu 610023China

To learn the process of urban land evolution before and after an earthquake is vital to formulate the urban reconstruction control policies and recovery measures in the earthquake-stricken ***,spatiotemporal evolution and its driving factors of urban land in earthquake-prone areas remains limited due to the scarcity of ground observation *** research,leveraging night-time light remote sensing imagery and land cover data,conducted a comprehensive analysis of the long-term evolution characteristics of urban land in earthquake-prone *** introduced methodologies for assessing the socio-economic impact and the primary natural environmental factors driving urban land evolution in these *** validate the proposed methods,the 2008 Wenchuan earthquake-affected area in China was selected as a representative study *** results indicated that the average Digital Number(DN)values in socio-economically impacted areas showed a trend of rising,falling,and then rising again after the *** values in three types of damaged areas including Type Ⅱ,Type Ⅲ,and Type Ⅳ exceeded pre-earthquake *** analysis of determinative factors influencing urban land evolution revealed that slope and elevation were key elements in controlling urban land expansion before the earthquake,whereas factors such as slope,elevation,lithology,and faults had a stronger influence on urban land expansion after the *** can be seen that,in view of the differences in the natural conditions of regions for post-disaster reconstruction,the local government need to actively adjust and adapt to urban spatial planning,so as to leverage the scale effect of large-scale inputs of funds,facilities,human resources and other factors after the disaster,thus enhancing resilience and recovery efficiency in response to disaster impacts.

关键词： Wenchuan earthquake Night-time lights Urban land Post-earthquake reconstruction

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A method for support stiffness failure identification in a steel spring floating slab track of urban railway: a case study in China

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Journal of Zhejiang University-Science A(Applied Physics & engineering) 2024年第3期25卷 206-222页

作者： Junyuan ZHENG Caiyou ZHAO Duojia SHI Ping WANG Jian WANG Bolong JIANG Xi SHENG Key Laboratoryof High-speed Railway engineering Ministry of EducationSouthwest Jiaotong UniversityChengdu 60031China School of Civil engineering Southwest Jiaotong UniversityChengdu 610031China 01 DYNA(Qingdao)Test&data Co. Ltd.Qingdao 266000China Rail Transit Digital Construction and Measurement Technology national engineering research center China Railway Design CorporationTianjin300308China Institute of Urban Smart Transportation&Safety Maintenance Shenzhen UniversityShenzhen 518060China

The extensive use of steel spring floating slab tracks has effectively addressed the challenge of alleviating the environmental vibrations induced by urban rail transit ***,under the combined action of train dynamic loads and complex environmental factors,problems,such as the fracture of steel spring vibration isolators and suspension vibrations induced by the uneven settlement of the base,often *** failure of isolator support stiffness is often hidden in its early stages and is challenging to identify by conventional detection *** the same time,it will aggravate the wheel-rail interaction,accelerate the deterioration of track structure,and even affect the driving *** study first establishes a detailed coupled train-floating slab track-foundation analytical *** the influence of the vibration isolator support stiffness failure on the dynamic indices of the floating slab track system response is analyzed.A set of defect identification methods that can detect the number of failed steel springs,severity of damage,and their location is ***,an intelligent monitoring system for support stiffness of floating slab track is built by combining the density-based spatial clustering of applications with noise algorithm and statistical data analysis and is applied to a rail line in southern *** a three-year monitoring campaign,a suspension failure and a fracture of a steel spring were each successfully detected and detailed failure information was *** investigation results were consistent with the damage identification *** repair,the track structure dynamic response returned to the average pre-damage level and further deterioration had been *** proposed damage identification methods and monitoring system provide an approach for intelligent identification of track structure support stiffness failures.

关键词： Floating slab track Support stiffness Detailed analytical model Failure identification Monitoring system

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Debris Flow Susceptibility Evaluation in Meizoseismal Region:A Case Study in Jiuzhaigou,China

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Journal of Earth Science 2024年第1期35卷 263-279页

作者： Yongwei Li Linrong Xu Yonghui Shang Shuyang Chen School of Civil engineering Central South UniversityChangsha 410075China national engineering research center of High-Speed Railway Construction Technology Central South UniversityChangsha 410075China School of Civil engineering Central South University of Forestry and TechnologyChangsha 410004China

Jiuzhaigou is situated on a mountain-canyon region and is famous for frequent tectonic *** abundance of loose co-seismic landslides and collapses were produced on gullies after the Jiuzhaigou Earthquake on August 8,2017,which was served as material source for debris flow in later *** flow appears frequently which are seriously endangering the safety of people's lives and *** the earliest debris flow appeared in areas where no case ever reported *** debris flow susceptibility evaluation(DFSE)is used for predicting the areas prone to debris flow,which is urgently required to avoid hazards and help to guide the strategy of preventive ***,this work employs debris flow in Jiuzhaigou to reveal the characteristics of disaster-pregnant environment and to explore the application of machine learning in *** new viewpoints are suggested:(i)Material density factor of debris flow is first adopted in this work,and it is proved to be a critical factor for triggering debris flows by sensitivity analysis method.(ii)Deep neural network and convolutional neural network(CNN)achieve relatively good area under the curve(AUC)values and are 0.021-0.024 higher than traditional machine learning methods.(iii)Watershed units combined with CNNbased model can achieve more accurate,reliable and practical susceptibility *** work provides an idea for prevention of debris flow in mountainous lands.

关键词： machine learning earthquakes debris flow susceptibility convolutional neural network deep neural network watershed unit

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