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Stabilization of coordinated motion for underwater vehicles

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Acta Mechanica Sinica 2011年第3期27卷 438-444页

作者： Fan Wu Zhi-yong geng State Key Laboratory for Turbulence and Complex Systems Peking University 100871 Beijing China

This paper presents a coordinating and stabilizing control law for a group of underwater vehicles with unstable dynamics. The coordinating law is derived from a potential that only depends on the relative configuration of the underwater vehicles. Being coordinated,the group behaves like one mechanical system with symmetry,and we focus on stabilizing a family of coordinated motions,called relative equilibria. The stabilizing law is derived using energy shaping to stabilize the relative equilibria which involve each vehicle translating along its longest（unstable） axis without spinning,while maintaining a relative configuration within the group. The proposed control law is physically motivated and avoids the linearization or cancellation of nonlinearities.

关键词： Underwater vehicles . Coordination .Relativeequilibria. Stabilization. Energy shaping

Coordinating control of multiple rigid bodies based on motion primitives

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Acta Mechanica Sinica 2012年第2期28卷 482-489页

作者： Fan Wu Zhi-yong geng State Key Laboratory for Turbulence and Complex Systems Peking University100871 BeijingChina

This paper studies the problem of coordinated motion generation for a group of rigid bodies. Two classes of coordinated motion primitives, relative equilibria and ma- neuvers, are given as building blocks for generating coordi- nated motions. In a motion-primitive based planning frame- work, a control method is proposed for the robust execution of a coordinated motion plan in the presence of perturba- tions. The control method combines the relative equilibria stabilization with maneuver design, and results in a close- loop motion planning framework. The performance of the control method has been illustrated through a numerical sim- ulation.

关键词： Coordinating control Motion plan execution Motion primitive. Relative equilibrium. Maneuver

Municipal solid waste management in Dalian： practices and challenges

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Frontiers of Environmental Science & Engineering 2012年第4期6卷 540-548页

作者： Xinbei WANG yong geng Institute of Applied Ecology Chinese Academy of ScienceShenyang 110016China

The fast growing of urban areas in developing countries has brought serious problems on municipal solid waste （MSW） management. It will be rational to adopt an integrated approach to deal with such a challenge so that the overall eco-efficiency of MSW management could be improved. To better examine how attributes of integrated MSW management are being interpreted and put into practice, and to explore what changes should be made to improve the application of integrated MSW management, we employ a case study method so that lessons learned could be used to inform initiatives in other cities and the potential solution may offer feasible strategies. The case study city is Dalian, a typical seaport city with fast growing rate in economy. The outcomes of this case study show us that fragmented management structure, ineffective and inefficient enforcement of relevant regulations, backward technologies, limited financial resources and lack of public participation are main barriers for the implementation of integrated MSW management. Consequently, in order to overcome these barriers, we propose an integrated management framework on MSW management, aiming to maximize the overall eco-efficiency of MSW management.

关键词： municipal solid waste (MSW) management 3R principles challenges eco-efficiency effective and efficient enforcement

Global Smooth Solutions to Relativistic Euler-Poisson Equations with Repulsive Force

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Acta Mathematicae Applicatae Sinica 2014年第4期30卷 1025-1036页

作者： yong-cai geng Lei WANG Department of Mathematics Shanghai Institute of Technology Wuxi Teachers' College

In this paper, we are concerned with the global existence of smooth solutions for the one dimen- sional relativistic Euler-Poisson equations： Combining certain physical background, the relativistic Euler-Poisson model is derived mathematically. By using an invariant of Lax＇s method, we will give a sufficient condition for the existence of a global smooth solution to the one-dimensional Euler-Poisson equations with repulsive force.

关键词： relativistic Euler equations relativistic Euler-poisson equations global existence characteristic-based method

2011—2020年中国大豆生产碳排放效率时空演变及影响因素

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中国人口·资源与环境 2024年第2期34卷 70-80页

作者：陈伟洪静兰李照令王亚平张天祚耿涌山东师范大学地理与环境学院山东济南250358 上海交通大学安泰经济与管理学院上海200030 山东大学环境科学与工程学院山东青岛266237 上海大学经济学院上海200444 上海交通大学国际与公共事务学院上海200030

准确分析大豆生产碳排放效率与影响因素,可为加快实现大豆生产碳减排提供理论依据与数据支撑。目前,鲜有关于中国大豆生产碳排放效率的研究,且尚未有关于大豆生产碳排放效率影响因素的研究。因此,该研究在选用生命周期评价法核算2011—2... 详细信息

准确分析大豆生产碳排放效率与影响因素,可为加快实现大豆生产碳减排提供理论依据与数据支撑。目前,鲜有关于中国大豆生产碳排放效率的研究,且尚未有关于大豆生产碳排放效率影响因素的研究。因此,该研究在选用生命周期评价法核算2011—2020年中国大豆生产全生命周期碳排放量的基础上,采用含有非期望产出的超效率SBM模型测算中国大豆生产碳排放效率,并基于Tobit模型探究影响中国大豆生产碳排放效率的主要因素。结果表明:①大豆生产碳排放总量呈现“上升—下降—上升”的3阶段变化特征,2020年大豆生产碳排放总量较2011年提升了47.70%;2020年单位产值大豆生产碳排放为7.48 t/万元,较2011年的5.64 t/万元增长了32.62%;大豆生产的碳排放强度则由2011年的5.16 t/hm2增至2020年的6.09 t/hm2,增长了18.02%。尽管碳排放整体呈上升趋势,但存在明显的区域差异,其中,黑龙江属于大豆生产碳排放总量大、单位产值碳排放高、碳排放强度高的地区,碳减排压力较大。②大豆生产碳排放效率呈先降后升的演变趋势,均值为0.78。主产区大豆生产碳排放效率空间差异明显,除山西、吉林碳排放效率年均变化率为负,其余地区大豆生产碳排放效率年均变化率均为正,且山西碳排放效率具有较大提升空间。③碳排放效率影响因素分析表明,作物种植结构、财政支农水平、农业机械化水平和农业技术水平对大豆生产碳排放效率具有显著正向作用,农业产业结构和农村劳动力受教育程度对大豆生产碳排放效率具有显著负向作用。建议提高农业机械化水平和财政支农水平,并基于大豆生产碳排放效率的区域异质性分类施策,以推动大豆生产绿色低碳发展,促进农业碳减排。

关键词：生命周期评价大豆碳排放效率影响因素超效率SBM Tobit模型

Spatiotemporal evolution and driving factors for GHG emissions of aluminum industry in China

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Frontiers in Energy 2023年第2期17卷 294-305页

作者： Chao TANG yong geng Xue RUI Guimei ZHAO School of Environmental Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China China Institute for Urban Governance School of International and Public AffairsShanghai Jiao Tong UniversityShanghai200030China SJTU-UNIDO Joint Institute of Inclusive and Sustainable Industrial Development School of International and Public AffairsShanghai Jiao Tong UniversityShanghai200030China School of Finance and Economics Jiangsu UniversityZhenjiang212013China

China’s aluminum(Al)production has released a huge amount of greenhouse gas(GHG)*** one of the biggest country of primary Al production,China must mitigate its overall GHG emission from its Al industry so that the national carbon neutrality target can be *** such a background,the study described in this paper conducts a dynamic material flow analysis to reveal the spatiotemporal evolution features of Al flows in China from 2000 to *** analysis is also performed to uncover the driving factors of GHG emission generated from the Al *** major findings include the fact that China’s primary Al production center has transferred to the western region;the primary Al smelting and carbon anode consumption are the most carbonintensive processes in the Al life cycle;the accumulative GHG emission from electricity accounts for 78.14% of the total GHG emission generated from the Al industry;China’s current Al recycling ratio is low although the corresponding GHG emission can be reduced by 93.73% if all the primary Al can be replaced by secondary Al;and the total GHG emission can be reduced by 88.58% if major primary Al manufacturing firms are transferred from Inner Mongolia to *** upon these findings and considering regional disparity,several policy implications are proposed,including promotion of secondary Al production,support of clean electricity penetration,and relocation of the Al industry.

关键词： aluminum material flow analysis GHG(greenhouse gas)emissions LMDI(logarithmic mean divisa index)

Effects of aging treatment on microstructure and mechanical properties of Cr25Ni35Nb and Cr35Ni45Nb furnace tube steel

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Acta Metallurgica Sinica(English Letters) 2011年第3期24卷 235-242页

作者： Limin SHEN Jianming GONG yong JIANG Luyang geng College of Mechanical and Power Engineering Nanjing University of Technology Nanjing 210009 China

Cr25Ni35Nb and Cr35Ni45Nb alloys are usually used in the ethylene cracking furnaces. However, premature failure of furnace tubes often occurs ahead of design life due to elevated temperature exposure conditions （1050-1100 ℃） and aggressive service environment. Effects of exposure temperature and time on microstructure and mechanical properties of Cr25Ni35Nb and Cr35Ni45Nb steel at aging temperature （1200 ℃） with various exposure time were simulated different service times at 1050 ℃. Change of mechanical properties at room temperature and elevated temperature （900 ℃） of the aged Cr25Ni35Nb and Cr35Ni45Nb steel were investigated. Under exposure at 1200 ℃, ultimate tensile and yield strength, elongation of Cr35Ni45Nb steel increase initially and then decrease, however, strength and ductility of Cr25Ni35Nb steel decrease with aging time increasing. Large amount of fine secondary carbide particles precipitated and dispersed in matrix of Cr35Ni45Nb steel, which increased strength and ductility for dispersion strengthening. However, the effect of the dispersion strengthening is weakened by needle-like secondary carbides. Strength and ductility decreased with fine secondary carbide particles growing. For Cr25Ni35Nb steel, few fine secondary carbide particles precipitated and dispersed in the matrix, and needle-like secondary carbides generated in the matrix, which causes strength and ductility decreased with aging time increasing.

关键词： Aging treatment Furnace tube steel Mechanical property Microstructure Cr25Ni35Nb Cr35Ni45Nb

Existence and Nonexistence of Global Positive Solutions for a Weakly Coupled P-Laplacian System

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Acta Mathematicae Applicatae Sinica 2013年第3期29卷 541-554页

作者： Xian-zhong ZENG Zhen-hai LI yong-geng GU School of Mathematics and Computing Science Hunan University of Science and Technology College of Science Guangxi University for Nationalities Department of Mathematics Hunan Normal University

In this paper, we deal with a weakly coupled evolution P-Laplacian system with inhomogeneous terms. We obtain a critical criterion concerning existence and nonexistence of its global positive solutions. Such a criterion is different from that of the weakly coupled evolution P-Laplacian system with homogeneous terms. Further, we demonstrate existence and nonexistence of its global positive solutions.

关键词： the evolution P-Laplacian system inhomogeneous terms blow-up global existence

Accounting greenhouse gas emissions of food consumption between urban and rural residents in China: a whole production perspective

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Frontiers in Energy 2022年第2期16卷 357-374页

作者： Yanfeng XU yong geng Ziyan GAO Shijiang XIAO Chenyi ZHANG Mufan ZHUANG China-UK Low Carbon College Shanghai Jiao Tong UniversityShanghai 200240China School of International and Public Affairs Shanghai Jiao Tong UniversityShanghai 200030China China Institute for Urban Governance Shanghai Jiao Tong UniversityShanghai 200030China School of Environmental Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China School of Management China University of Mining and TechnologyXuzhou 221116China

Food consumption is necessary for human *** a global scale,the greenhouse gas(GHG)emission related to food consumption accounts for 19%–29%of the total GHG *** has the largest population in the world,which is experiencing a rapid *** the background of urbanization and the adjustment of the diet structure of Chinese residents,it is critical to mitigate the overall GHG emission caused by food *** study aims to employ a single-region input-output(SRIO)model and a multi-regional input-output(MRIO)model to measure GHG emission generated from food consumption in China and compare the contributions of different industrial sectors,uncovering the differences between urban and rural residents and among different provinces(autonomous regions/municipalities),as well as identifying the driving forces of GHG emission from food consumption at a national *** results indicate that the total GHG emission generated from food consumption in China tripled from 157 Mt CO_(2)e in 2002 to 452 Mt CO_(2)e in *** fastest growing GHG emission is from the consumption of other processed food and meat *** GHG emissions from both urban and rural residents increased,the gap between them is ***,processing and manufacture of food,manufacture of chemical and transportation,storage and post services sectors are key sectors inducing food consumption related GHG *** a regional perspective,the top five emission provinces(autonomous regions/municipalities)include Shandong,Hubei,Guangdong,Zhejiang,and *** on such results,policy recommendations are proposed to mitigate the overall GHG emission from food consumption.

关键词： greenhouse gas(GHG)emission food consumption industry sectors mitigation measures urban governance