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Experimental study on dynamic mechanism of vortex evolution in a turbulent boundary layer of low Reynolds number

Journal of Hydrodynamics 2020年第5期32卷 807-819页

作者： Yan-ang guo Xiang-rui Dong Xiao-shu Cai Wu Zhou School of Energy and Power Engineering University of Shanghai for Science and TechnologyShanghai 200093China Key Laboratory of Multiphase Flow and Heat Transfer in Shanghai Power Engineering Shanghai 200093China

The dynamic mechanism of the vortex generation and evolution process in a fully developed turbulent boundary layer with Reθ=97-194 is experimentally *** this study,a moving single-frame and long-exposure(MSFLE)imaging method and a moving particle image velocimetry/particle tracing velocimetry(M-PIV/PTV)are designed and implemented for measuring the temporal and spatial evolution of vortex cores in both qualitative and quantitative ways,*** the other hand,the Liutex vector,which is a new mathematical definition and identification of the vortex core proposed by Liu’s group,is first applied in the experiment for the structural visualization and quantitative analysis of the local fluid *** results show that an intuitional process of vortex evolution can be clearly observed by tracking the vortex using MSFLE and verify that the roll-up of the shear layer induced by shear instability is the origin of vortex formation in ***,a quantitative investigation in terms of the critical vortex core boundary(size)and its accurate rotation strength is carried out based on the Liutex vector field analysis by M-PIV/*** to statistics of the relation between vortex core size and the rotation strength during the whole process,the physical mechanism of vortex generation and evolution in a turbulent boundary layer of low Reynolds number can be summarized as a four-dominant-state course consisting of the“synchronous linear segment(SL)-absolute enhancement segment(AE)-absolute diffusion segment(AD)-skewing dissipation segment(SD)”.

关键词： Turbulent boundary layer high-and low-speed fluid vortex generation moving single-frame and long-exposure moving particle image velocimetry/particle tracing velocimetry Liutex vector

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Status and trends of carbon emissions research at the county level in China

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Advances in Climate Change Research 2024年第2期15卷 338-352页

作者： ang-Zu CAI Ru guo Yu-Hao ZHang Jiang WU College of Environmental Science and Engineering Institute of Environmental Planning and ManagementTongji UniversityShanghai 200092China Institute of Carbon Neutrality Tongji UniversityShanghai 200092China Shanghai Institute of Pollution Control and Ecological Security Shanghai 200092China College of Architecture and Urban Planning Tongji UniversityShanghai 200092China Megacity Elaborated Urban Governance Institute Tongji UniversityShanghai 200092China

This study provides a comprehensive overview of the challenges to achieving carbon neutrality at the county level in China and offers targeted recommendations,laying the groundwork for future specialized research in this area.A total of 283 relevant studies(2004-2023)were analyzed to assess county-level carbon emissions through three phases:bibliometric analysis,frontier analysis,and future *** findings reveal that publication trends were largely influenced by domestic and foreign *** cluster discerns ten primary themes,ranging from conceptual frameworks to research *** frontier analysis of the literature highlights the leading research areas,which include carbon neutrality pathway,driving factors,spatiotemporal variation of carbon emissions,the co-effects of pollutants and carbon reduction,and carbon emissions in China's rural *** from the results of bibliometric and frontier analyses,this study elucidates the recommendations for achieving carbon neutrality at the county level from three perspectives:effective regional policy guidance,emphasis on ecological conservation,and the deployment of advanced carbon reduction and sequestration *** study enriches the body of knowledge on carbon emissions at the county level and holds significant implications for China's comprehensive push towards achieving its carbon neutrality objectives.

关键词： Carbon emissions Emission reduction County Carbon neutrality Sustainability

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Parallel implementation of w-projection wide-field imaging

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Science Bulletin 2019年第9期64卷 586-594页

作者： Baoqiang Lao Tao An ang Yu Wenhui Zhang Junyi Wang Quan guo Shaoguang guo Xiaocong Wu Shanghai Astronomical Observatory Key Laboratory of Radio AstronomyChinese Academy of Sciences Guangxi Cooperative Innovation Center of Cloud Computing and Big Data Guilin University of Electronic Technology Guangxi Colleges and Universities Key Laboratory of Cloud Computing and Complex Systems Guilin University of Electronic Technology

w-Projection is a wide-field imaging technique that is widely used in radio synthesis arrays. Processing the wide-field big data generated by the future Square Kilometre Array(SKA) will require significant updates to current methods to significantly reduce the time consumed on data processing. Data loading and gridding are found to be two major time-consuming tasks in w-projection. In this paper, we investigate two parallel methods of accelerating w-projection processing on multiple nodes: the hybrid Message Passing Interface(MPI) and Open Multi-Processing(OpenMP) method based on multicore Central Processing Units(CPUs) and the hybrid MPI and Compute Unified Device Architecture(CUDA)method based on Graphics Processing Units(GPUs). Both methods are successfully employed and operated in various computational environments, confirming their robustness. The experimental results show that the total runtime of both MPI + OpenMP and MPI + CUDA methods is significantly shorter than that of single-thread processing. MPI + CUDA generally shows faster performance when running on multiple nodes than MPI + OpenMP, especially on large numbers of nodes. The single-precision GPU-based processing yields faster computation than the double-precision processing; while the single-and doubleprecision CPU-based processing shows consistent computational performance. The gridding time remarkably increases when the support size of the convolution kernel is larger than 8 and the image size is larger than 2,048 pixels. The present research offers useful guidance for developing SKA imaging pipelines.

关键词： Radio synthesis arrays Square kilometre array Wide field imaging Parallelization w-Projection

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Ce-modified USY zeolite catalysts for catalytic oxidation of chlorinated VOCs:Effect of the location of CeO_(2) and its synergistic effect with USY zeolite

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Journal of Rare Earths 2024年第11期42卷 2068-2077,I0003页

作者： Xiaolin guo Zhiming Li ang Zhou Yijun Shi Yong Wang Renxian Zhou Institute of Catalysis Zhejiang UniversityHangzhou310028China College of Materials and Chemistry China Jiliang UniversityHangzhou310018China

The catalytic behavior of a catalyst for chlorine-containing volatile organic compounds(CVOCs) oxidation largely depends on the synergistic interaction between the oxidizing and acidic *** the present work,two catalysts with different distributions of CeO_(2) on the inner and outer surfaces of 4.0Ce-USY-ex and 4.0Ce-USY-dp(USY zeolite) were prepared respectively by ion exchange and deposition methods,with a purpose of finding out how the location of the oxidation sites(CeO_(2)) influence its synergistic effect with the acidic sites of *** results show that 4.0Ce-USY-ex is much more active for catalytic degradation of 1,2-dichloroethane(DCE),while 4.0Ce-USY-dp catalyst exhibit higher catalytic degradation activity for other structured CVOCs(dichloromethane(DCM),trichloroethylene(TCE),chlorobenzene(CB)).CeO_(2) in 4.0Ce-USY-ex catalyst mainly disperses in the pore channels of USY zeolite,and there are many strong acid centers on the surface,which is conducive to the dechlorination conversion of ***,CeO_(2) in 4.0Ce-USY-dp catalyst is mainly distributed on the outer surface of USY and has strong oxidation ability,which contributes to the deep oxidation of ***,the presence of a large number of strong acid centers on the catalyst surface of 4.0Ce-USY-ex catalysts leads to severe accumulation of surface carbon species and significantly decreases its stability towards ***,a large number of active oxygen species on the surface of 4.0Ce-USY-dp and CeO_(2) catalysts are beneficial to the deep oxidation of DCE,reducing the formation of surface carbon and thus improving the stability of the ***,the influence of the location of the oxidation sites on its synergistic effect with the acidic sites was established in the present work,which could provide some new ideas for the rational design of CVOCs degradation catalyst with appropriate distribution of active sites.

关键词： CVOCs oxidation CeO_(2) USY Location Synergistic effect Rare earths

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Research on virtual entity decision model for LVC tactical confrontation of army units

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Journal of Systems Engineering and Electronics 2022年第5期33卷 1249-1267页

作者： GAO ang guo Qisheng DONG Zhiming Tang Zaijiang ZHang Ziwei FENG Qiqi Military Exercise and Training Center Army Academy of Armored ForcesBeijing 100072China

According to the requirements of the live-virtual-constructive(LVC)tactical confrontation(TC)on the virtual entity(VE)decision model of graded combat capability,diversified actions,real-time decision-making,and generalization for the enemy,the confrontation process is modeled as a zero-sum stochastic game(ZSG).By introducing the theory of dynamic relative power potential field,the problem of reward sparsity in the model can be *** reward shaping,the problem of credit assignment between agents can be *** on the idea of meta-learning,an extensible multi-agent deep reinforcement learning(EMADRL)framework and solving method is proposed to improve the effectiveness and efficiency of model *** show that the model meets the requirements well and the algorithm learning efficiency is high.

关键词： live-virtual-constructive(LVC) army unit tactical confrontation(TC) intelligent decision model multi-agent deep reinforcement learning

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Operational effectiveness evaluation based on the reduced conjunctive belief rule base

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Journal of Systems Engineering and Electronics 2022年第5期33卷 1161-1172页

作者： ZHang Ziwei guo Qisheng DONG Zhiming LIU Hongxiang GAO ang QI Pengcheng Military Exercise and Training Center Army Academy of Armored ForcesBeijing 100072China Unit 32128 of the PLA Ji’nan 250024China Department of Equipment Support and Remanufacture Army Academy of Armored ForcesBeijing 100072China

To address the issue of rule premise combination explosion in the construction of the traditional complete conjunctive belief rule base(BRB),this paper introduces an orthogonal design method to reduce the conjunctive *** reasoning method based on reduced conjunctive BRB is designed with the help of the conversion technology from conjunctive BRB to disjunctive ***,the operational mission effectiveness evaluation is taken as an example to verify the proposed *** results show that the method proposed in this paper is feasible and effective.

关键词： operational effectiveness evaluation reduced conjunctive belief rule base(BRB) orthogonal design evidence reasoning(ER)

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Phase-field-lattice Boltzmann study for lamellar eutectic growth in a natural convection melt

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China Foundry 2017年第5期14卷 373-378页

作者： ang Zhang Zhi-peng guo Shou-mei Xiong School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China Key Laboratory for Advanced Materials Processing Technology Ministry of Education Tsinghua UniversityBeijing 100084China

In the present study, the influence of natural convection on the lamellar eutectic growth is determined by a phase-field-lattice Boltzmann study for Al-Cu eutectic alloy. The mass difference resulting from concentration difference led to the fluid flow, and a robust parallel and adaptive mesh refinement algorithm was employed to improve the computational efficiency without any compromising accuracy. Results show that the existence of natural convection would affect the growth undercooling and thus control the interface shape by adjusting the lamellar width. In particular, by alternating the magnitude of the solute expansion coefficient, the strength of the natural convection is changed. Corresponding microstructure patterns are discussed and compared with those under no-convection conditions.

关键词： natural convection lamellar width phase field model lattice Boltzmann method

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Systematical strategies for wastewater treatment and the generated wastes and greenhouse gases in China

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Frontiers of Environmental Science & Engineering 2012年第2期6卷 271-279页

作者： Jingbo guo Fang MA Yuanyuan QU ang LI Liang Wang School of Civil Engineering Northeast Dianli UniversityJilin 132012China State Key Laboratory of Urban Water Resource and Environment School of Municipal and Environmental EngineeringHarbin Institute of TechnologyHarbin 150090China Key Laboratory of Industrial Ecology and Environmental Engineering(Ministry of Education) School of Environmental Science and TechnologyDalian University of TechnologyDalian 116024China Vanillin Factory Jilin Petrochemical CompanyChina National Petroleum CorporationJilin 132021China

China now faces double challenges of water resources shortage and severe water pollution. To resolve Chinese water pollution problems and reduce its impacts on human health, economic growth and social develop- ment, the situation of wastewater treatment was investi- gated. Excess sludge and greenhouse gases （GHGs） emitted during wastewater treatment were also surveyed. It is concluded that Chinese water pollution problems should be systematically resolved with inclusion of wastewater and the solid waste and GHGs generated during wastewater treatment. Strategies proposed for the wastewater treatment in China herein were also adequate for other countries, especially for the developing countries with similar economic conditions to China.

关键词： wastewater treatment solid waste greenhousegases systematical strategies

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Lightweight and high-security laser-based cotton tip pruning robot

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International Journal of Agricultural and Biological Engineering 2024年第4期17卷 98-108页

作者： Xuan'ang guo Ziyang Mao Zedong Shi Wei Lu School of Artificial Intelligence Nanjing Agricultural UniversityNanjing 210031China

Considering the current environmental pollution caused by chemical topping,plant damage caused by mechanical topping,and the high cost of manual topping,a laser-based cotton-tip pruning robot for field cotton was designed in this *** main advantages of this robot include its safety,light weight,low cost,and environmental ***,the structural design,measurement,and corresponding control system design of the robot were ***,a precise laser control method based on Yolov5 cotton top identification and the inverse kinematic solution of parallel robot rapid positioning were ***,the optimal laser irradiation wavelength and duration were ***,a laser-topping experiment was conducted,and the overall accuracy and recall rates for cotton identification were 98.3%and 99.3%,*** AP and mAP at the threshold value of 0.5 reached 99.3%and 78.8%,*** maximum positioning error of the jacking system is 2.6 mm,and the repeated positioning error is within±1.2 cm,which meets the accuracy requirements of laser ***-purple laser irradiation at 15 W and 405 nm for 22 s was the best topping *** the effects of cotton topping with and without manual topping,it can be seen that laser topping significantly improved the yield and *** with the photothermal response of the cotton topping,the feasibility of laser topping was verified both theoretically and *** laser-topping scheme proposed in this study exhibits high efficiency,environmental protection,and safety,as well as good application prospects.

关键词： laser topping parallel manipulator photothermal response object detection

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Immobilization of Bovine Serum Albumin on Poly(ether ether ketone) for Surface Biocompatibility Improvement

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Chemical Research in Chinese Universities 2012年第2期28卷 353-357页

作者： SUN Hui CHEN Rui-chao LI ang XU guo-zhi School of Materials Science and Mechanical Engineering Beijing Technology and Business UniversityBeijing 100048P R.China

UV-induced graft polymerization of acrylic acid（AA） on poly（ether ether ketone）（PEEK） films was carried out to introduce ―COOH for the subsequent immobilization of bovine serum albumin（BSA）.BSA was introduced on PEEK surface based on the condensation reaction between ―NH 2 and ―*** modified surface（PEEK-BSA） was characterized by energy-disperse spectrometry（EDS）,X-ray photoelectron spectroscopy（XPS）,water contact angle measurement and UV spectrum *** contact angle was found to decrease from 104° for the virgin PEEK films to 63° for the BSA-immobilized PEEK films,demonstrating a significant improvement of surface ***,the appearance of nitrogen on PEEK film confirmed by XPS and EDS indicates the immobilization of BSA on PEEK surface.

关键词： Poly(ether ether ketone)(PEEK) UV-grafting Bovine serum albumin immobilization

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