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Numerical study on local failures of reinforced concrete slabs against underwater close-in explosions

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第8期25卷 650-669页

作者： fei ZHOU Hedong LI Hao WU College of Civil Engineering Tongji UniversityShanghai 200092China School of Civil Engineering and Architecture Zhejiang Sci-Tech UniversityHangzhou 310018China

Reinforced concrete(RC)slabs are the primary load-carrying member of underwater *** can suffer severe local failures such as cratering,spalling,or breaching as a result of underwater close-in(UWCI)*** this study,we established a fully validated high-fidelity finite element analysis approach to precisely reproduce the local failures of RC slabs after a UWCI explosion.A recently proposed dynamic constitutive model is used to describe wet *** effects of free water content on the material properties,including the tensile/compressive strength,elastic modulus,strain rate effect,failure strength surface,and equation of state,are comprehensively calibrated based on existing test *** calibrated material parameters are then verified by a single-element test.A high-fidelity finite element analysis(FEA)approach of an RC slab subjected to a UWCI explosion is established using an arbitrary Lagrangian-Eulerian(ALE)*** previous UWCI explosion tests on RC orifice targets and underwater contact explosion tests on saturated concrete slabs showed that the established FEA approach could accurately reproduce the pressure-time history in water and damage patterns,including the cracking,cratering,and spalling,of the RC orifice target and saturated concrete ***,parametric studies conducted by simulating an RC slab subjected to a UWCI explosion showed that:(i)the local failure of an RC slab enlarges with increased charge weight,reduced standoff distance,and reduced structural thickness;(ii)compared to a water-backed RC slab,an air-backed RC slab exhibits much more obvious local and structural ***,to aid the anti-explosion design of relevant underwater facilities,based on over 90 simulation cases empirical formulae are summarized to predict local failure modes,i.e.,no spall,spall,and breach,of water-and air-backed RC slabs subjected to a UWCI explosion.

关键词： Reinforced concrete slab(RC) Underwater close-in(UWCI)explosion Saturated concrete Failure modes Numerical simulation

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CFD-DEM study of impacts of the porous distributor medium on fluidization characteristics of a 2D-fluidized bed

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Particuology 2024年第4期87卷 54-73页

作者： fei Wang Yishan Zeng Hao Yan School of Mechanical Engineering Hefei University of TechnologyHefei230009China

Gas-solid bubbling fluidized beds are widely used in chemical,energy,construction,and other industrial fields due to their excellent fluidization performance.2D-fluidized beds with planar rectangular columns of finite thickness are widely used in fluidized bed studies,and it is essential for understanding the hydrodynamics of gas-particle ***,the distributor(porous medium)at the bottom of the bed has a crucial influence on the fluidization performance of the 2D-fluidized *** this work,the fluidization mechanism and gas-solid dynamic characteristics of the fluidized bed under three porous media are studied by CFD-DEM coupled with the porous medium model,and the accuracy of numerical simulation is verified by a high-speed photography *** show that with the increase in the flow resistance of the porous medium,the average and standard deviation of the bubble diameter decrease,and the time and position of particles in the dead zone to participate in the core-annular flow *** a low fluidization velocity,the dead zone in the bed can be considerably reduced by increasing the flow resistance.

关键词： Fluidized bed CFD-DEM Porous medium Bubble dynamics Solid mixing

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Even Search in a Promising Region for Constrained Multi-Objective Optimization

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IEEE/CAA Journal of Automatica Sinica 2024年第2期11卷 474-486页

作者： fei Ming Wenyin Gong Yaochu Jin School of Computer Science China University of GeosciencesWuhan 430074China IEEE Faculty of Technology Bielefeld UniversityNorth Rhine-Westphalia 33619Germany School of Engineering Westlake UniversityHangzhou 310030China

In recent years, a large number of approaches to constrained multi-objective optimization problems(CMOPs) have been proposed, focusing on developing tweaked strategies and techniques for handling constraints. However, an overly finetuned strategy or technique might overfit some problem types,resulting in a lack of versatility. In this article, we propose a generic search strategy that performs an even search in a promising region. The promising region, determined by obtained feasible non-dominated solutions, possesses two general ***, the constrained Pareto front(CPF) is included in the promising region. Second, as the number of feasible solutions increases or the convergence performance(i.e., approximation to the CPF) of these solutions improves, the promising region shrinks. Then we develop a new strategy named even search,which utilizes the non-dominated solutions to accelerate convergence and escape from local optima, and the feasible solutions under a constraint relaxation condition to exploit and detect feasible regions. Finally, a diversity measure is adopted to make sure that the individuals in the population evenly cover the valuable areas in the promising region. Experimental results on 45 instances from four benchmark test suites and 14 real-world CMOPs have demonstrated that searching evenly in the promising region can achieve competitive performance and excellent versatility compared to 11 most state-of-the-art methods tailored for CMOPs.

关键词： Constrained multi-objective optimization even search evolutionary algorithms promising region real-world problems

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Considering solid shear stress in MP-PIC simulation of a CFB riser

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Particuology 2024年第6期89卷 79-87页

作者： Tagir Kadyrov fei Li Atta Ullah Nature-inspired Engineering Center University of TyumenTyumen 625003Russia Laboratory of Theory and Optimization of Chemical and Technological Processes University of TyumenTyumen625003Russia State Key Laboratory of Multi-phase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China Department of Chemical Engineering Pakistan Institute of Engineering&Applied SciencesIslamabad 45650Pakistan

To enable successful multi-phase particle-in-cell(MP-PIC)simulations of circulating fluidized beds(CFBs),both the interphase drag force and interparticle collisions need to be carefully *** collisions are usually represented by the solid stress consisting of the normal and shear components,in which the normal stress was found to have a leading role in the numerical stability of MP-PIC simulations,whereas the impact of the shear stress has seldom been *** this work,the effects of the solid shear stress are investigated by using two-dimensional simulations of the moderately dense laboratory-scale CFB riser with in-house MP-PIC code implemented on MFIX open-source *** including only normal solid stress and those considering both normal and shear solid stresses are *** results of solids flux,axial and radial solids profiles are compared with available experimental *** results show that the solid shear stress plays a minor role on the accuracy of simulation,and the increase of PPP(number particles per parcel)leads to a lower accuracy of simulation.

关键词： Simulation Fluidization Multiphase particle-in-cell(MP-PIC) Solid shear stress

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Partial Linear Model Averaging Prediction for Longitudinal Data

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Journal of Systems Science & Complexity 2024年第2期37卷 863-885页

作者： LI Na fei Yu ZHANG Xinyu Faculty of Science Kunming University of Science and TechnologyKunming 650500China School of Statistics and Mathematics Yunnan University of Finance and EconomicsKunming 650221China Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China

Prediction plays an important role in data *** averaging method generally provides better prediction than using any of its *** though model averaging has been extensively investigated under independent errors,few authors have considered model averaging for semiparametric models with correlated *** this paper,the authors offer an optimal model averaging method to improve the prediction in partially linear model for longitudinal *** model averaging weights are obtained by minimizing criterion,which is an unbiased estimator of the expected in-sample squared error loss plus a *** properties,including asymptotic optimality and consistency of averaging weights,are established under two scenarios:(i)All candidate models are misspecified;(ii)Correct models are available in the candidate *** studies and an empirical example show that the promise of the proposed procedure over other competitive methods.

关键词： Asymptotic optimality longitudinal data model averaging estimator partially linear model prediction

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Fusion of Spiral Convolution-LSTM for Intrusion Detection Modeling

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Computers, Materials & Continua 2024年第5期79卷 2315-2329页

作者： fei Wang Zhen Dong School of Cyberspace Security Gansu University of Political Science and LawLanzhou73000China

Aiming at the problems of low accuracy and slow convergence speed of current intrusion detection models,SpiralConvolution is combined with Long Short-Term Memory Network to construct a new intrusion detection *** dataset is first preprocessed using solo thermal encoding and normalization *** the spiral convolution-Long Short-Term Memory Network model is constructed,which consists of spiral convolution,a two-layer long short-term memory network,and a *** is shown through experiments that the model is characterized by high accuracy,small model computation,and fast convergence speed relative to previous deep learning *** model uses a new neural network to achieve fast and accurate network traffic intrusion *** model in this paper achieves 0.9706 and 0.8432 accuracy rates on the NSL-KDD dataset and the UNSWNB-15 dataset under five classifications and ten classes,respectively.

关键词： Intrusion detection deep learning spiral convolution long and short term memory networks 1D-spiral convolution

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On the Optimal Initial Inner-Core Size for Tropical Cyclone Intensification: An Idealized Numerical Study

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Advances in Atmospheric Sciences 2024年第11期41卷 2141-2155页

作者： Rong fei Yuqing WANG School of Atmospheric Sciences and Remote Sensing Wuxi UniversityWuxi 214105China State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China International Pacific Research Center Department of Atmospheric SciencesSchool of Ocean and Earth Science and TechnologyUniversity of Hawaii at ManoaHonoluluHawaii 96822USA

Recent observational and numerical studies have revealed the dependence of the intensification rate on the inner-core size of tropical cyclones(TCs). In this study, with the initial inner-core size(i.e., the radius of maximum wind—RMW)varied from 20–180 km in idealized simulations using two different numerical models, we found a nonmonotonic dependence of the lifetime maximum intensification rate(LMIR) on the inner-core size. Namely, there is an optimal innercore size for the LMIR of a TC. tangential wind budget analysis shows that, compared to large TCs, small TCs have large inward flux of absolute vorticity due to large absolute vorticity inside the RMW. However, small TCs also suffer from strong lateral diffusion across the eyewall, which partly offsets the positive contribution from large inward flux of absolute vorticity. These two competing processes ultimately lead to the TC with an intermediate initial inner-core size having the largest LMIR. Results from sensitivity experiments show that the optimal size varies in the range of 40–120 km and increases with higher sea surface temperature, lower latitude, larger horizontal mixing length, and weaker initial TC intensity. The 40–120 km RMW corresponds to the inner-core size most commonly found for intensifying TCs in observations, suggesting the natural selection of initial TC size for intensification. This study highlights the importance of accurate representation of TC inner-core size to TC intensity forecasts by numerical weather prediction models.

关键词： tropical cyclones intensification inner-core size idealized simulations

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Test of the Brans-Dicke theory with GW200105 and GW200115

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Communications in Theoretical Physics 2024年第7期76卷 83-93页

作者： Qin fei Yingjie Yang Department of Mathematics and Physics School of Biomedical EngineeringSouthern Medical UniversityGuangzhou 510515China School of Mathematics and Physics Hubei Polytechnic UniversityHuangshi 435003China

We study whether it is possible to constrain the Brans-Dicke(BD)theory from the measurement of gravitational waves(GW)released in neutron star-black hole *** the scalar field modifications through monopole and dipole radiations,we find additional contributions to the phase evolution in the emitted gravitational *** effectively calculating such effect in the post-Newtonian order,we are in a position to measure the scalar field and give bounds on the BD coupling parameterω_(BD).We derive the analytical expression for the phase modification due to the orbital eccentricity of eccentric binaries in both general relativity and BD *** the Bayesian analysis,we obtain the constraints on ω_(BD) from the GW events,GW200105 and GW200115.

关键词： cosmology Brans-Dicke theory gravitational wave

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鞭檐犁头尖抗癌活性及其潜在机制临床前研究的系统综述

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Journal of Traditional Chinese Medical Sciences 2023年第4期10卷 403-414,520页

作者： Ng Kwok Wen tan Suk fei Looi Shu Ying Naimat Faiza Hamid Hazrina Faculty of Pharmacy Quest International University School of Pharmacy Management and Science University Faculty of Pharmacy Universiti Teknologi MARACawangan Selangor Faculty of Pharmacy Lincoln University College

目的:评价一种中药植物鞭檐犁头尖(***)作为抗癌药物的临床前研究的系统综述。方法:对Scopus、PubMed、Web of Science、ScienceDirect、LILACS、EBSCO Medline、Mendeley等7个数据库进行全面检索,检索时间截止到2023年9月8日。排除了... 详细信息

目的:评价一种中药植物鞭檐犁头尖(***)作为抗癌药物的临床前研究的系统综述。方法:对Scopus、PubMed、Web of Science、ScienceDirect、LILACS、EBSCO Medline、Mendeley等7个数据库进行全面检索,检索时间截止到2023年9月8日。排除了临床试验和非原创的同行评议报告后,鞭檐犁头尖的提取物,组成,或分离化合物的体内外研究且经过同行评审的英文文献均被纳入。本研究定性评估了鞭檐犁头尖对不同肿瘤细胞、肿瘤大小和作用机制的有效性。证据质量由三名独立评估人员使用ToxRTool进行评估,并验证其一致性。结果:检索后共纳入27项研究:22项体外研究,4项体内研究,1项体内外研究。结果发现鞭檐犁头尖对白血病、乳腺癌、结直肠癌和肺癌有效。大多数研究的评估为“有限制的可靠”。鞭檐犁头尖通过阻断细胞周期、活化caspase-3/-9、分解PARP、裂解DNA、减少生存素含量、降低ROS表达、抑制COX-2和HSP70表达和抑制NF-kB通路等来诱导细胞凋亡。当与干扰素联合使用时,其能阻碍血管生成。结论:尽管鞭檐犁头尖具有良好的抗癌活性,但其作为单独抗癌药物的疗效尚不确定。它似乎更适合用于癌症的补充或联合治疗。研究设计不理想,报告不完整,以及在多篇文章中没有纳入适当的阳性对照和统计分析可能是本研究缺乏结论性证据的原因。

关键词：鞭檐犁头尖水半夏 Rodent tuber 癌症系统综述

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Slowing down of the summer Southern Hemisphere Annular Mode trend against the background of ozone recovery

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Atmospheric and Oceanic Science Letters 2024年第1期17卷 1-8页

作者： fei Zheng School of Atmospheric Sciences Key Laboratory of Tropical Atmosphere-Ocean SystemMinistry of EducationSun Yat-sen UniversityZhuhaiChina Southern Marine Science and Engineering Guangdong Laboratory ZhuhaiChina

20世纪末期,南半球热带外地区经历了显著的气候变化,包括夏季南半球环状模(SAM)的显著上升趋势,伴随着南极半岛的增暖和别林斯高晋海的海冰融化.这些趋势主要是由20世纪末期南极平流层臭氧消耗所驱动的.本文发现,自2001年左右以来,在南... 详细信息

20世纪末期,南半球热带外地区经历了显著的气候变化,包括夏季南半球环状模(SAM)的显著上升趋势,伴随着南极半岛的增暖和别林斯高晋海的海冰融化.这些趋势主要是由20世纪末期南极平流层臭氧消耗所驱动的.本文发现,自2001年左右以来,在南极平流层臭氧恢复的背景下,观测到的夏季SAM的上升趋势已经趋于平缓,验证了前人利用数值模拟预测的夏季SAM上升趋势减缓现象,与SAM在臭氧恢复后趋势只减缓但没有逆转不同,南极地表气温和海冰的趋势发生了逆转.南极半岛由变暖趋势转为降温趋势,别林斯高晋海域的海冰由融化趋势转为增多趋势.

关键词：南半球环状模南极臭氧损耗南极臭氧恢复

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