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Analysis of China’s PM_(2.5)and ozone coordinated control strategy based on the observation data from 2015 to 2020

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Journal of Environmental Sciences 2024年第4期138卷 385-394页

作者： Liuwei Kong Mengdi Song Xin Li Ying Liu Sihua Lu Limin Zeng Yuanhang Zhang State Key Joint laboratory of Environmental simulation and Pollution Control College of Environmental Sciences and EngineeringPeking UniversityBeijing 100871China

The coordinated control of PM_(2.5)and ozone has become the strategic goal of national air pollution *** the gradual decline in PM_(2.5)concentration and the aggravation of ozone pollution,a better understanding of the coordinated control of PM_(2.5)and ozone is urgently ***,we collected and sorted air pollutant data for 337 cities from 2015 to 2020 to explore the characteristics of PM_(2.5)and ozone pollution based on China’s five major air pollution *** results show that it is necessary to continue to strengthen the emission reduction in PM_(2.5)and ozone precursors,and control NO_(x) and VOCs while promoting a dramatic emission reduction in PM_(2.5).The primary method of curbing ozone pollution is to strengthen the emission control of VOCs,with a long-term strategy of achieving substantial emission reductions in NO_(x),because VOCs and NO_(x) are also precursors to PM_(2.5);hence,their reductions also contribute to the reduction in PM_(2.5).Therefore,the implementation of a multipollutant emission reduction control strategy aimed at the prevention and control of PM_(2.5)and ozone pollution is the only means to realize the coordinated control of PM_(2.5)and ozone.

关键词： PM_(2.5) Ozone Coordinated control Multipollutant reduction

Development of CONTHAC-3D and hydrogen distribution analysis of HPR1000

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Nuclear Science and Techniques 2024年第2期35卷 210-221页

作者： Hui Wang Jing-Jing Li Yuan Chang Gong-Lin Li Ming Ding China Nuclear Power engineering Co.LTD. Beijing 100084China Fundamental Science on Nuclear Safety and simulation Technology laboratory Harbin 100049China

An in-house code,CONTHAC-3D,was developed to calculate and analyze thermal-hydraulic phenomena in containments during severe ***-3D is a three-dimensional computational fluid dynamics code that can be applied to predict gas flow,diffusion,and steam condensation in a containment during a severe hypothetical accident,as well as to obtain an estimate of the local hydrogen concentration in various zones of the ***-3D was developed using multiple models to simulate the features of the proprietary systems and equipment of HPR1000 and ACP100,such as the passive cooling system,passive autocatalytic recombiners and the passive air cooling *** validate CONTHAC-3D,a GX6 test was performed at the Battelle Model Containment *** hydrogen concentration and temperature monitored by the GX6 test are accurately predicted by ***,the hydrogen distribution in the HPR1000 containment during a severe accident was *** results show that the hydrogen removal rates calculated using CONTHAC-3D for different types of PARs agree well with the theoretical values,with an error of less than 1%.As the accident progresses,the hydrogen concentration in the lower compartment becomes higher than that in the large space,which implies that the lower compartment has a higher hydrogen risk than the dome and large space at a later stage of the *** amount of hydrogen removed by the PARs placed on the floor of the compartment is small;therefore,raising the installation height of these recombiners appropriately is ***,we do not recommend installing all autocatalytic recombiners at high *** study findings in regard to the hydrogen distribution in the HPR1000 containment indicate that CONTHAC-3D can be applied to the study of hydrogen risk containment.

关键词： Hydrogen risk mitigation Pressurized water reactor HPR1000 Thermal hydraulic CONTHAC-3D

Experimental,Numerical,and Analytical Studies on the Bending of Mechanically Lined Pipe

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China Ocean engineering 2024年第2期38卷 221-232页

作者： WEI Wen-bin YUAN Lin ZHOU Jia-sheng LIU Zheng State Key laboratory of Hydraulic engineering simulation and Safety Tianjin UniversityTianjin 300072China School of Civil engineering Tianjin UniversityTianjin 300072China School of Mechanical engineering Tianjin UniversityTianjin 300072China

Mechanically lined pipe(MLP)is often used for offshore oil and gas transport because of its low cost and corrosion *** installation and operation,the pipe may undergo severe bending deformation,which causes the liner to separate from the outer pipe and buckles,affecting the stability of the whole *** this paper,the buckling response of MLP subjected to bending is investigated to clarify its bending characteristics by employing both experiments,numerical simulation,as theoretical *** types of MLPs were manufactured with GB 45 carbon steel(SLP)and Al 6061(ALP)used as the outer pipe material,*** hydraulic expansion and bending experiments of small-scale MLPs are *** addition to the ovalized shape of the cross-section for the SLP specimens,the copper liner was found to wrinkle on the compressive *** contrast,the liner of ALP remains intact without developing any wrinkling and collapse *** addition,a dedicated numerical framework and theoretical models were also *** was found both the manufacturing and bending responses of the MLP can be well reproduced,and the predicted maximum moment and critical curvatures are in good agreement with the experimental results.

关键词： lined pipe bending nonlinear ring theory buckling plasticity

Dynamic Coupling Analysis of Semisubmersible Platform Float-over Method for Docking Case

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Journal of Ocean University of China 2024年第2期23卷 345-357页

作者： DING Hongyan QIN Licheng ZHANG Puyang SONG Zhengrong XIE Weiwei State Key laboratory of Hydraulic engineering simulation and Safety Tianjin UniversityTianjin 300072China Offshore Oil engineering Co. Ltd.Tianjin 300461China

In this paper,the multi-body coupled dynamic characteristics of a semisubmersible platform and an HYSY 229 barge were ***,coupled hydrodynamic analysis of the HYSY 229 barge and the semisubmersible platform was *** hydrodynamic parameters were obtained using the retardation function method of three-dimensional frequency-domain potential flow *** results of the hydrodynamic analysis were highly consistent with the test findings,verifying the accuracy of the multifloating hydrodynamic coupling analysis,and key hydrodynamic parameters were solved for different water depths and the coupling *** to the obtained results,the hydrodynamic influence was the largest in shallow waters when the coupling effect was ***,the coupled motion equation combined with viscous damping,fender system,and mooring system was established,and the hydrodynamics,floating body motion,and dynamic response of the fender system were *** analysis revealed good agreement among the surge,sway,and yaw motions of the two floating ***,when the wave period reached 10 s,the motion of the two floating bodies showed severe shock,and a relative motion was also ***,excessive constraints should be added between the two floating bodies during construction to ensure construction *** numerical analysis and model test results of the semisubmersible platform and HYSY 229 barge at a water depth of 42 m and sea conditions of 0°,45°,and 90° were in good agreement,and the error was less than 5%.The maximum movement of the HYSY 229 barge reached 2.61 m in the sway direction,whereas that of the semisubmersible platform was 2.11 *** construction,excessive constraints should be added between the two floating bodies to limit their relative movement and ensure construction safety.

关键词： float-over method semisubmersible platform coupling hydrodynamic fender system time-domain analysis

Wind-Vortex-Induced Vibrations of a Deepwater Jacket Pipe and Vibration Suppression Using a Nonlinear Energy Sink

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Journal of Ocean University of China 2024年第3期23卷 633-642页

作者： LIU Liqin YU Yongjun CHEN Yiqun State Key laboratory of Hydraulic engineering simulation and Safety Tianjin UniversityTianjin 300072China China Classification Society Haikou 570102China

The purpose of this study is to investigate the suppression effect of a nonlinear energy sink(NES)on the wind-vortex-induced pipe vibration and explore the influence of damping,stiffness,and NES installation position on the suppression *** this work,the wind-vortex-induced vibration of an elastic pipe of a deepwater jacket was studied,and vibrations were suppressed by using an NES.A van der Pol wake oscillator was used to simulate vortex-induced force,and the dynamic equation of the pipe considering the NES was *** Galerkin method was applied to discretize the motion equation,and the vortex-induced vibration(VIV)of the pipe at reduced wind speeds was numerically *** novelty of this research is that particle swarm optimization was used to optimize the parameters of the NES to improve vibration *** influence of the installation position,nonlinear stiffness,and damping parameters of the NES on vibration suppression was *** showed that the optimized parameter combinations of the NES can effectively reduce wind-vortex-induced pipe *** installation position of the NES had a significant effect on vibration suppression,and the midpoint of the pipe was the optimal NES installation *** increase in stiffness or a 10% decrease in damping may cause vibration suppression *** results of this study provide some guidance for VIV suppression in deepwater jacket pipes.

关键词： deepwater jacket wind-vortex-induced vibration NES PSO vibration suppression effect analysis

Experimental Study on Impingement Processes of Fuel Sprays on Biomimetic Structured Surfaces

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Journal of Bionic engineering 2024年第1期21卷 362-373页

作者： Yanling Chen Liang Guo Wanchen Sun Yuying Yan Rong Xuan Junfeng Zhang State Key laboratory of Automotive simulation and Control Jilin UniversityChangchun 130025China Faculty of engineering University of NottinghamNottingham NG72RDUK

To improve the controllability of the wall-wetting process after the fuel spray-wall impingement in internal combustion engines,the methods of laser etching,chemical etching and surface free energy modification are used to prepare biomimetic structured surfaces with different *** impingement processes of diesel and n-butanol sprays on the walls under different conditions are experimentally *** the surface oleophilicity increases,the spreading radius of wall-impinging sprays *** about 5 s after the fuel injections,the fuel spray droplets hit the walls for the first time,and the secondary breakup and rebound *** mixture concentrations of different fuels hitting the various walls reach the peak *** a higher surface temperature,the peak value of the mixture concentration is mainly related to the heat flux to the fuel droplets in different boiling regimes from the metal *** concentration of the air–fuel mixture in the near wall region increases with increasing surface oleophilicity,increasing wall temperature and decreasing ambient *** with diesel,n-butanol presents a higher air–fuel mixture concentration in the near wall region.

关键词： Spray-wall impingement Morphological development Air-fuel mixture concentration Surface wettability Wall temperature:Ambient pressure

Electrical tree degradation of MgO/epoxy resin composites at different voltage frequencies

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High Voltage 2024年第3期9卷 581-590页

作者： Yunxiao Zhang Wenxin Lin Yuanxiang Zhou Weiwei Xing Jiayu Cheng Chenyuan Teng College of Electrical engineering and Automation Fuzhou UniversityFujian Key Laboratory of New Energy Generation and Power ConversionFuzhouChina State Key laboratory of Control and simulation of Power Systems and Generation Equipment Department of Electrical EngineeringTsinghua UniversityBeijingChina

Electrical tree degradation is one of the main causes of insulation failure in high-frequency *** tree degradation is studied on pure epoxy resin(EP)and MgO/EP composites at frequencies ranging from 50 Hz to 130 *** results show that the tree initiation voltage of EP decreases,while the growth rate and the expansion coefficient increase with ***,the bubble phenomenon at high frequencies in EP composites is *** with trap distribution character-istics within the material,the intrinsic mechanism of epoxy composites to inhibit the growth of the electrical tree at different frequencies is *** can be concluded that more deep traps and blocking effect are introduced by doping nano-MgO into EP bulks,which can improve the electrical tree resistance performance of EP composites in a wide frequency range.

关键词： composites tree Electrical

Towards optimized tensor code generation for deep learning on sunway many-core processor

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Frontiers of Computer Science 2024年第2期18卷 1-15页

作者： Mingzhen LI Changxi LIU Jianjin LIAO Xuegui ZHENG Hailong YANG Rujun SUN Jun XU Lin GAN Guangwen YANG Zhongzhi LUAN Depei QIAN State Key laboratory of Software Development Environment Beijing 100191China School of Computer Science and engineering Beihang UniversityBeijing 100191China National University of Singapore Singapore 119077Singapore State Key laboratory of Mathematical engineering and Advanced Computing Wuxi 214000China Science and Technology on Special System simulation laboratory Beijing simulation Center Beijing 100854China Department of Computer Science and Technology Tsinghua UniversityBeijing 100084China

The flourish of deep learning frameworks and hardware platforms has been demanding an efficient compiler that can shield the diversity in both software and hardware in order to provide application *** the existing deep learning compilers,TVM is well known for its efficiency in code generation and optimization across diverse hardware *** the meanwhile,the Sunway many-core processor renders itself as a competitive candidate for its attractive computational power in both scientific computing and deep learning *** paper combines the trends in these two ***,we propose swTVM that extends the original TVM to support ahead-of-time compilation for architecture requiring cross-compilation such as *** addition,we leverage the architecture features during the compilation such as core group for massive parallelism,DMA for high bandwidth memory transfer and local device memory for data locality,in order to generate efficient codes for deep learning workloads on *** experiment results show that the codes generated by swTVM achieve 1.79x improvement of inference latency on average compared to the state-of-the-art deep learning framework on Sunway,across eight representative *** work is the first attempt from the compiler perspective to bridge the gap of deep learning and Sunway processor particularly with productivity and efficiency in *** believe this work will encourage more people to embrace the power of deep learning and Sunwaymany-coreprocessor.

关键词： sunway processor deep learning compiler code generation performance optimization

Analysis of Weakly Nonlinear Evolution Characteristics of Flow in the Constant Curvature Bend

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Advances in Applied Mathematics and Mechanics 2024年第1期16卷 101-121页

作者： Bin Li Haijue Xu Yuchuan Bai Ziqing Ji Skate Key laboratory of Hydraulic engineering simulation and Safety Tianjin UniversityTianjin 300072China Institute for Sedimentation on River and Coastal engineering Tianjin 300072China

The meandering river is an unstable system with the characteristic of nonlinearity,which results from the instability of the flow and *** on the hydrodynamic nonlinearity of the bend,we use the weakly nonlinear theory and perturbation method to construct the nonlinear evolution equations of the disturbance amplitude and disturbance phase of two-dimensional flow in meandering *** influence of the curvature,Re and the disturbance wave number on the evolution of disturbance amplitude and disturbance phase are ***,the spatial and temporal evolution of the disturbance vorticity is *** research results show:that the curvature makes the flow more stable;that in the evolution of the disturbance amplitude effected by curvature,Re and the disturbance wave number,exist nonlinear attenuation with damping disturbances,and nonlinear explosive growth with positive disturbances;that the asymmetry distribution of the disturbance velocities increases with the curvature;that the location of the disturbance vorticity’s core area changes periodically with disturbance phase,and the disturbance vorticity gradually attenuates/increases with the decrease of the disturbance phase in the evolution process of damping/positive *** results shed light on the construction of the interaction model of hydrodynamic nonlinearity and geometric nonlinearity of bed.

关键词： Curvature bend hydrodynamics weakly nonlinearity disturbance vorticity