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Numerical investigation of the coupled aero-hydrodynamic performances of a semi-submersible floating offshore wind turbine with inclined columns

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Journal of Hydrodynamics 2024年第2期36卷 316-330页

作者： Ying-jie Xue Xiao-long Yang Wei-wen Zhao De-cheng Wan computational Marine Hydrodynamics Lab(CMHL) School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China Offshore Oil Engineering co.ltd. Tianjin300461China

Numerical investigations of floating platforms with different outer column inclined angles under two operating conditions of regular wave and irregular wave are presented in this paper.A coupled aero-hydrodynamic computational fluid dynamics in-house solver FOWT-UALM-SJTU is applied for the ***,the validation for wave and wind generation are conducted to determine mesh distribution *** on these,the hydrodynamic motion response,aerodynamic performance and wake flow are analyzed to explore the impact of inclined *** spectral analysis on the motion response under wave action,discuss the aerodynamic attack angle and inflow wind velocity along the blade spanwise direction in detail,reveal different trends in wake development and *** results show that for the regular wave condition with the increase of inclined angles,the equilibrium position of surge motion is constantly rising,while pitch is *** maximum root mean square(rms)value occurs at angle=30°,compared with the original OC4 FOWT,the rms in power and thrust increase 0.35%,0.71%.And there are two low regions of attack angle and high regions of axial inflow velocity,corresponding to aerodynamic *** spectral analysis indicates that the natural frequency of pitch motion will increase with inclined ***,from the middle to far region of wake flow,the velocity recovery of FOWT with inclined angle will become faster,which is beneficial for downstream turbines to enhance more wind energy.

关键词： Floating offshore wind turbine numerical simulation aero-hydrodynamic coupled analysis floating platform with inclinedcolumns wake flow recovery

Numerical analysis of coupled sloshing and motion of a cylindrical FPSO in regular waves

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Journal of Hydrodynamics 2024年第3期36卷 457-465页

作者： Wei-wen Zhao Xiao-long Yang De-cheng Wan computational Marine Hydrodynamics Lab(CMHL) School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China Offshore Oil Engineering co.ltd. Tianjin300461China

In this paper,the coupled sloshing and motion characteristics of a cylindrical floating production storage offloading(CFPSO)are numerically investigated by means of computational fluid dynamics(CFD)*** simulations are performed using an in-house CFD solver naoe-FOAM-SJTU which is developed based on *** active wave generating-absorbing boundary condition(GABC)is utilized for wave generation and *** stabilized k-omega SST turbulence model are used to avoid excessive eddy viscosity near the free *** with and without partially filled liquid tanks in regular waves with different wave periods are simulated and vertical planar motions such as surge,heave and pitch response amplitude operators(RAOs)are *** due to liquid sloshing and wave loads are extracted and *** free surface motions inside liquid tanks in one wave period presented to explain the motion characteristics.

关键词： coupled analysis liquid sloshing wave motion cylindrical floating production storage offloading(CFPSO)

Milling degree affects the fermentation properties of rice:perspectives from the composition of nutrients and gut microbiota via in vitro fermentation

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Food Science and Human Wellness 2024年第3期13卷 1578-1588页

作者： Yu Zhang Fan Li Shutong Pan Bing Bai Kai Huang Sen Li Hongwei Cao Tian Xie Jian Xie Xiao Guan School of Health Science and Engineering University of Shanghai for Science and TechnologyShanghai 200093China National Grain Industry(Urban Grain and Oil Security)Technology Innovation Center Shanghai 200093China Nutrition&Health Research Institute co.ltd. COFCO CorporationBeijing 102209China China Grain Wuhan Scientific Research&Design Institute co.ltd. Wuhan 430079China

Fermentation substrates of rice with different milling degrees(MDs) were prepared and fermented with human feces to compare their fermentation properties and effects on gut *** 0s,MD 5s and MD 60s represented brown rice,moderately-milled rice and white rice,*** in vitro fermentation,the MD 5s group showed higher starch utilization,compared with the MD 0s and 60s groups evaluated by Fourier transform infrared spectrometer,and confocal laser scanning *** of fermentation substrates of rice with different MDs on gut microbiota were evaluated by 16S rDNA *** the sample groups reduced the pH and produced short-chain fatty acids(SCFAs) and branched-chain fatty *** MD 5s group exhibited higher α-diversity than the MD 0s and 60s *** of Phascolarctobacterium,Blautia and norank_f_Ruminococcaceae were higher in the MD 0s and 5s groups,compared with the MD 60s *** bacteria were also positively correlated with the SCFAs production via Spearman correlation *** vitro culture assay revealed that fermentation substrates of MD 0s and 5s promoted the growth of two probiotics(Akkermansia muciniphila and Bifidobacterium adolescentis).Our results showed that moderate milling might be an appropriate way to produce rice products with richer nutrients and better fermentation properties.

关键词： Rice processing Milling Whole grains Gut microbiota

Novel wreck salvaging method using curved rectangular pipe basing method:A case study of"Yangtze River EstuaryⅡ"ancient shipwreck salvage project

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Underground Space 2024年第5期18卷 97-113页

作者： Qianwei Zhuang Guofang Gong Dongrong Zhou Chi Zhang Xin Huang Xiaodong Zhu Weihao Yuan Deng Li School of Mechanical Engineering Zhejiang UniversityHangzhou 310030China shanghai Tunnel Engineering co.ltd. Shanghai 200137China Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China college of Civil Engineering and Architecture Xinjiang UniversityUrumqi 830047China shanghai Salvage company Shanghai 200090China

Shipwreck salvage is a risky,time-consuming,and expensive *** there are many sunken ships along coastlines and in the open seas,the salvage process of a sunken ship has rarely been *** integrated salvage of the"Yangtze River EstuaryⅡ"shipwreck used a novel method with 22 closely locked curved rectangular pipes to form a watertight base that wrapped the shipwreck *** basing was lifted out of the water using a powerful crane situated on an engineering *** the first time,the tunneling method was used in a shipwreck salvage project,significantly reducing the disturbance to the shipwreck and its stowage,thereby preserving the original state and integrity of the shipwreck to the greatest *** this study,the basic concepts of the salvage method and process are *** to critical issues in the new salvage method are provided,including jacking force prediction and major considerations for the structural design of the salvage *** design of the salvage system and salvage process of the"Yangtze River EstuaryⅡ"shipwreck are *** monitored jacking force,pipe deformation,and observed water-tightness verified that the proposed method was effective and *** possible application scenarios for the proposed method are presented at the end.

关键词： Pipe jacking Shipwreck salvage Yangtze River EstuaryⅡ Structural design

Geometrical transition properties of vortex cavitation and associated flow-choking characteristics in poppet valves

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第6期25卷 455-469页

作者： Liang LU Zhongdong LIANG Yuming LIU Zhipeng WANG Shohei RYU School of Mechanical Engineering Tongji UniversityShanghai 201804China Frontiers Science Center for Intelligent Autonomous Systems Tongji UniversityShanghai 201210China Technical Research Laboratory Hitachi Construction Machinery Co.Ltd.Tsuchiura 300-0013Japan

Poppet valves have become increasingly significant in ensuring precise digital flow rate and pressure control in hydraulic systems,necessitating a more profound understanding of the geometrical properties of cavitation in them,as well as associated flow-choking *** a comparative analysis with experimentally observed cavity images,we found that large eddy simulation(LES)turbulence modeling effectively replicates the geometrical properties of cavitation in these *** analysis demonstrated that cavitation is generated from vortices that result from the interaction between the notch contracta flow and the surrounding fluid *** in the internal or external vena contracta conditions result in fixed or discrete cavities,and the length-to-diameter ratio serves as a measure of the transition between internal and external vena contracta flow *** study establishes a threshold length-to-diameter ratio of approximately 2 for the tested poppet *** specifically,in notch structures with a smaller valve opening,longer sealing length,and smaller throttling angle(corresponding to a larger length-to-diameter ratio),the liquid-to-vapor transfer process is more evident than that in the reverse direction.A long-standing vapor cavity becomes fixed inside the notch,leading to a more pronounced flow-choking *** contrast,for structures with a smaller length-to-diameter ratio,the cavitation process for discrete vapor cavities is more complete,ensuring fluid flow continuity and significantly reducing the occurrence of the flow-choking phenomenon.

关键词： Poppet valves Vena contracta Vortex flow Vapor cavity Flow-choking

Recent advances in halide perovskite memristors:From materials to applications

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Frontiers of physics 2024年第2期19卷 73-104页

作者： Sixian Liu Jianmin Zeng Qilai Chen Gang Liu Department of Micro/Nano Electronics School of Electronic Information and Electrical EngineeringShanghai Jiao Tong UniversityShanghai 200240China Aerospace Science&Industry Shenzhen(Group)co.ltd. Shenzhen 518000China

With the emergence of the Internet of Things(IoT)and the rapid growth of big data generated by edge devices,there has been a growing need for electronic devices that are capable of processing and transmitting data at low power and high *** complementary Metal-Oxide-Semiconductor(CMOS)devices are nonvolatile and often limited by their ability for certain IoT applications due to their unnecessary power consumption for data movement in von Neuman architecture-based *** has led to a surge in research and development efforts aimed at creating innovative electronic components and systems that can overcome these shortcomings and meet the evolving needs of the information era,which share features such as improved energy efficiency,higher processing speeds,and increased *** are a novel type of electronic device that has the potential to break down the barrier between storage and *** storing data and processing information within the same device,memristors can minimize the need for data movement,which allows for faster processing speeds and reduced energy *** further improve the energy efficiency and reliability of memristors,there has been a growing trend toward diversifying the selection of dielectric materials used in *** perovskites(HPs)have unique electrical and optical properties,including ion migration,charge trapping effect caused by intrinsic defects,excellent optical absorption efficiency,and high charge mobility,which makes them highly promising in applications of *** this paper,we provide a comprehensive overview of the recent development in resistive switching behaviors of HPs and the underlying ***,we summarize the diverse range of HPs,their respective performance metrics,as well as their applications in various ***,we critically evaluate the current bottlenecks and possible opportunities in the future research of HP memristors.

关键词： halide perovskite memristor mechanism neuromorphic computing non-volatile memory

Evaluation on cutting performance of novel PDC cutter for pipe jacking machine

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Underground Space 2024年第1期14卷 34-52页

作者： Long-Chuan Deng Yi-Xiang Yuan Xiao-Zhao Li Qian-Wei Zhuang Chi Zhang Yi-Wei Chen School of Earth Sciences and Engineering Nanjing UniversityNanjingJiangsu 210023China shanghai Tunnel Engineering co.ltd. Shanghai 200232China State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhouJiangsu 221116China School of Mechanics and Engineering Science Shanghai UniversityShanghai 200444China

It is inevitable to cut reinforced concrete(RC)appeared in cross passage of city metro by cutting tools when constructing in densely populated *** previous cutters employed to cut RC are insufficient and easily damaged,so a new polycrystalline diamond compact(PDC)cutter is used to solve this *** on the theoretical analysis of cutting mechanism,both circular and tapered PDC cutters with cutting edge angle of 90and negative front rack angle of 10are used to cut *** peeling and breaking patterns of cutting concrete are proposed,the nodular and grainy chips are the preferred modes in cutting steel *** LS-DYNA is employed to investigate the cutting performance in *** simulation results show that the average and peak cutting forces increase with the growth of penetration depth,cutting speed,and roundness,and subsequently the recommended penetration depth less than 1.2 mm is obtained to cut RC due to the existence of steel ***,the linear cutting platform is adopted to investigate the force ability and damage state of PDC *** is concluded that the cutting force increases abruptly and fluctuates heavily when cutting the coarse *** patterns occurred in both numerical and experimental results are generally ***,the steel bar is pulled out and the PDC cutter is damaged at the penetration depth of 0.8 mm,while a good cut occurs at the penetration depth of 0.3 *** tapered PDC cutter with a relatively low cutting force is prone to be broken compared with circular PDC *** is suggested that the circular PDC cutter at the penetration depth of 0.3 mm should be used to cut RC in practical engineering.

关键词： PDC cutter RC Pipe jacking machine Linear cutting tests Damage and wear LS-DYNA

End-to-End Paired Ambisonic-Binaural Audio Rendering

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IEEE/CAA Journal of Automatica Sinica 2024年第2期11卷 502-513页

作者： Yin Zhu Qiuqiang Kong Junjie Shi Shilei Liu Xuzhou Ye Ju-Chiang Wang Hongming Shan Junping Zhang shanghai Key Laboratory of Intelligent Information Processing School of Computer ScienceFudan UniversityShanghai 200433China Beijing ByteDance Technology co.ltd. Shanghai 201102China. Chinese University of Hong Kong Hong KongChina IEEE Institute of Science and Technology for Brain-Inspired Intelligence and MOE Frontiers Center for Brain Science Fudan UniversityShanghai 200433 shanghai Center for Brain Science and Brain-Inspired Technology Shanghai 200031China

Binaural rendering is of great interest to virtual reality and immersive media. Although humans can naturally use their two ears to perceive the spatial information contained in sounds, it is a challenging task for machines to achieve binaural rendering since the description of a sound field often requires multiple channels and even the metadata of the sound sources. In addition, the perceived sound varies from person to person even in the same sound field. Previous methods generally rely on individual-dependent head-related transferred function(HRTF)datasets and optimization algorithms that act on HRTFs. In practical applications, there are two major drawbacks to existing methods. The first is a high personalization cost, as traditional methods achieve personalized needs by measuring HRTFs. The second is insufficient accuracy because the optimization goal of traditional methods is to retain another part of information that is more important in perception at the cost of discarding a part of the information. Therefore, it is desirable to develop novel techniques to achieve personalization and accuracy at a low cost. To this end, we focus on the binaural rendering of ambisonic and propose 1) channel-shared encoder and channel-compared attention integrated into neural networks and 2) a loss function quantifying interaural level differences to deal with spatial information. To verify the proposed method, we collect and release the first paired ambisonic-binaural dataset and introduce three metrics to evaluate the content information and spatial information accuracy of the end-to-end methods. Extensive experimental results on the collected dataset demonstrate the superior performance of the proposed method and the shortcomings of previous methods.

关键词： Ambisonic attention binaural rendering neural network

Thickness regression for backfill grouting of shield tunnels based on GPR data and CatBoost&BO-TPE:A full-scale model test study

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Underground Space 2024年第4期17卷 100-119页

作者： Kang Li Xiongyao Xie Biao Zhou Changfu Huang Wei Lin Yihan Zhou Cheng Wang Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China State Key Laboratory of Disaster Reduction in Civil Engineering Tongji UniversityShanghai 200092China Key Laboratory of Geotechnical and Underground of Ministry of Education Tongji UniversityShanghai 200092China China Railway 15th Bureau Group co.ltd. Shanghai 200070China State Grid shanghai Municipal Electric Power company Shanghai 200122China

Ground penetrating radar(GPR)is a vital non-destructive testing(NDT)technology that can be employed for detecting the backfill grouting of shield *** achieve intelligent analysis of GPR data and overcome the subjectivity of traditional data processing methods,the CatBoost&BO-TPE model was constructed for regressing the grouting thickness based on GPR waveforms.A full-scale model test and corresponding numerical simulations were carried out to collect GPR data at 400 and 900 MHz,with known backfill grouting *** model test helps address the limitation of not knowing the grout body condition in actual field *** data were then used to create machine learning *** method of feature selection was proposed based on the analysis of feature importance and the electromagnetic(EM)propagation law in *** research shows that:(1)the CatBoost&BO-TPE model exhibited outstanding performance in both experimental and numerical data,achieving R^(2)values of 0.9760,0.8971,0.8808,and 0.5437 for numerical data and test data at 400 and 900 *** outperformed extreme gradient boosting(XGBoost)and random forest(RF)in terms of performance in the backfill grouting thickness regression;(2)compared with the full-waveform GPR data,the feature selection method proposed in this paper can promote the performance of the *** selected features within the 5–30 ns of the A-scan can yield the best performance for the model;(3)compared to GPR data at 900 MHz,GPR data at 400 MHz exhibited better performance in the CatBoost&BO-TPE *** indicates that the results of the machine learning model can provide feedback for the selection of GPR parameters;(4)the application results of the trained CatBoost&BO-TPE model in engineering are in line with the patterns observed through traditional processing methods,yet they demonstrate a more quantitative and objective nature compared to the traditional method.

关键词： Shield tunnel Backfill grouting GPR Model test gprMax Machine learning CatBoost&BO-TPE Thickness regression