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Numerical Simulation Investigation on Parameter Optimization of Deep-Sea Mining Vehicles

Chinese Journal of Mechanical Engineering 2023年第2期36卷 365-377页

作者： Hongyun Wu Wei Liu Min Jiang Changfeng Li Jiangming Li bingzheng chen Chunlai Wang Yuheng chen Institute of Marine Research Changsha Mining Research Institute Co.Ltd.Changsha 410012China School of Mechanical and Electrical Engineering Central South UniversityChangsha 410083China School of Energy and Engineering China University of Mining&Technology BeijingBeijing 100083China

The four-track walking mining vehicle can better cope with the complex terrain of cobalt-rich crusts on the seabed.To explore the influence of different parameters on the obstacle-crossing ability of mining vehicles,this paper took a certain type of mine vehicle as an example and establish a mechanical model of the mine vehicle.Through this model,the vehicle's traction coefficient variation could be analyzed during the obstacle-crossing process.It also reflected the relationship between the obstacle-crossing ability and the required traction coefficient.Many parameters were used for this analysis including the radius of the guide wheel radius,ground clearance of the driving wheel,the dip angle of the approaching angular and the position of centroid.The result showed that the ability to cross the obstacles requires adhesion coefficient as support.When the ratio between obstacle height and ground clearance of the guide wheel was greater than 0.7,the required adhesion coefficient increased sharply.The ability to cross obstacles will decrease,if the radius of the guide wheel increases,the height of the driving wheel increases or the dip angle of the approaching angular increases.It was most beneficial to cross the obstacle when-the ratio of the distance between the center of mass and the front driving wheel to the wheelbase is between 0.450.48.The results of this paper could provide reference for structural parameter design and performance research for mining vehicles.

关键词： Rich crusts Four-track vehicles Triangular track Obstacle-crossing

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Life-insurance Efficiency in China:A Comparison of Foreign and Domestic Firms

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China & World Economy 2009年第6期17卷 43-63页

作者： bingzheng chen Michael R. Powers Joseph Qiu Professor of Finance School of Economics and Management Tsinghua University Beijing China Professor of Risk Management and Insurance Fox School of Business Temple University Philadelphia USA Consultant Towers Perrin Philadelphia USA

中国人寿保险的工业在最近的年里经历了主要结构的变化，首先因为增加需求和外国保险公司的入口。尽管市场清楚地正在蓬勃发展，它的生长和发展的效率是不清楚的。在这篇论文，我们评估在中国操作的生活保险公司的效率并且把外国公司与... 详细信息

中国人寿保险的工业在最近的年里经历了主要结构的变化，首先因为增加需求和外国保险公司的入口。尽管市场清楚地正在蓬勃发展，它的生长和发展的效率是不清楚的。在这篇论文，我们评估在中国操作的生活保险公司的效率并且把外国公司与国内公司作比较。我们发现外国保险公司没把效率带进中国市场，并且市场是静止的，这由国内巨人统治了。然而，在外国保险公司之间的差距和国内保险公司正在变窄。在测试以后，考虑的假设放大经济，技术进步和潜在的改进，我们讨论重要性的几个问题到生活保险公司，市场投资者和政府管理者。

关键词：人寿保险公司国内企业外国公司中国人中国市场经营效率假设检验经济规模

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基于概率信息与协作学习的鲁棒T-S模糊建模方法

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天津大学学报（自然科学与工程技术版） 2024年第1期57卷 87-94页

作者：江敏吴鸿云柏昀旭陆新江陈秉正中南大学机电工程学院长沙410083 长沙矿山研究院有限责任公司长沙410012 国家金属采矿工程技术研究中心长沙410012 天津大学机械工程学院天津300072

T-S模糊建模方法在非线性系统建模中取得了大量的应用.然而,T-S模型在参数辨识过程中忽略了结构风险项,同时没有考虑各个规则之间的联系,因此在数据受到非高斯噪声和异常点的影响时,模型容易失效.针对以上不足,提出了基于概率信息与协... 详细信息

T-S模糊建模方法在非线性系统建模中取得了大量的应用.然而,T-S模型在参数辨识过程中忽略了结构风险项,同时没有考虑各个规则之间的联系,因此在数据受到非高斯噪声和异常点的影响时,模型容易失效.针对以上不足,提出了基于概率信息与协作学习的模糊建模方法.该方法建立了规则之间协作学习机制以保证模型的连续性、平滑性与鲁棒性,并进一步构建了包含正则化项、误差项、规则概率信息及规则之间协作关系项的目标函数,用于提高模型的泛化能力和建模性能.除此之外,建立了空间投影机制,将数据低维特征空间的非线性关系转换为高维投影空间的线性关系,以增强规则之间的协作性.针对该模型,建立了基于最小二乘的求解方法,获得了可靠的模型参数.数学算例仿真和实际锻压实验表明:所提出的方法在面对噪声以及强非线性影响时,依然能在规则数较低的情况下保持优秀的建模性能.对比其他优秀的模糊建模方法,该模型有着更强的抗干扰能力,且建模均方根误差(RMSE)远低于其他建模方法.综上所述,所提出的方法对传统方法和建模理论进行了改进,即使面对强非线性系统拥有较强的泛化能力、鲁棒性以及优秀的建模能力,并且能够以较少的模糊规则对工程当中非线性、不确定性系统建模.

关键词：模糊建模概率信息协作学习噪声鲁棒性

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中国老年人健康状态转移概率估计——基于两个数据库的比较分析

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系统工程理论与实践 2020年第11期40卷 2848-2860页

作者：陈秉正范宸清华大学经济管理学院北京100084

本文分别运用中国老年人健康长寿影响因素调查(CLHLS)和中国健康与养老追踪调查(CHARLS)两个常用的微观数据库对中国老年人健康状态转移概率进行估计,并对估计结果进行比较研究.在选取了相同的状态转移概率估计模型的情况下,本文发现使... 详细信息

本文分别运用中国老年人健康长寿影响因素调查(CLHLS)和中国健康与养老追踪调查(CHARLS)两个常用的微观数据库对中国老年人健康状态转移概率进行估计,并对估计结果进行比较研究.在选取了相同的状态转移概率估计模型的情况下,本文发现使用CLHLS数据库与使用CHARLS数据库相比,估计出的健康状态恶化的概率更低,但不同健康状态下的死亡概率更高.对两个数据库进行对比发现,它们在调查对象、抽样方法、样本量以及调查时间四个方面存在较大差异.结合两个数据库各自的优势,本文对估计中国老年人健康状态转移概率时数据库的选取提出了建议.对中国老年人健康状态转移概率的研究能够为我国长期护理保险制度建设提供决策依据.

关键词：健康状态转移概率比较分析马尔可夫过程

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气候变化背景下全球极端天气事件GDP损失率评估

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系统工程理论与实践 2019年第3期39卷 557-568页

作者：梁荣陈秉正清华大学经济管理学院中国保险与风险研究中心北京100084

本文通过研究不同碳排放情景下未来70年全球气温上升的可能性,量化了极端天气事件对全球GDP可能造成的损失.首先,本文采用DICE模型评估了未来每十年全球GDP年损失率的离散概率分布;然后利用本文提出的一种新的广义对数正态分布函数,对... 详细信息

本文通过研究不同碳排放情景下未来70年全球气温上升的可能性,量化了极端天气事件对全球GDP可能造成的损失.首先,本文采用DICE模型评估了未来每十年全球GDP年损失率的离散概率分布;然后利用本文提出的一种新的广义对数正态分布函数,对未来每十年全球GDP年损失率的概率分布进行了拟合;最后,通过计算极端天气事件发生频率分别小于0.5%, 1%, 5%情形时GDP损失率的范围,讨论了不同碳排放情景下GDP损失率尾部分布的差异,分析了温度变化对损失率的影响.结果表明:在不同碳排放情景下,全球年GDP损失率的概率密度曲线尾部均表现出小概率大损失的特征,本研究可为有关机构做好气候变化背景下巨灾风险损失的量化分析提供依据.

关键词：气候变化极端天气事件损失分布

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Atomically Dispersed Ruthenium Catalysts with Open Hollow Structure for Lithium-Oxygen Batteries

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Nano-Micro Letters 2024年第2期16卷 154-164页

作者： Xin chen Yu Zhang Chang chen Huinan Li Yuran Lin Ke Yu Caiyun Nan chen chen Beijing Advanced Innovation Center for Materials Genome Engineering Institute of Solid State ChemistryUniversity of Science and Technology BeijingBeijing 100083People’s Republic of China Engineering Research Center of Advanced Rare Earth Materials Department of ChemistryTsinghua UniversityBeijing 100084People’s Republic of China Beijing Key Laboratory of Energy Conversion and Storage Materials Institution College of ChemistryBeijing Normal UniversityBeijing 100875People’s Republic of China

Lithium–oxygen battery with ultrahigh theoretical energy density is considered a highly competitive next-generation energy storage device,but its practical application is severely hindered by issues such as difficult decomposition of discharge products at present.Here,we have developed N-doped carbon anchored atomically dispersed Ru sites cathode catalyst with open hollow structure(h-RuNC)for Lithium–oxygen battery.On one hand,the abundance of atomically dispersed Ru sites can effectively catalyze the formation and decomposition of discharge products,thereby greatly enhancing the redox kinetics.On the other hand,the open hollow structure not only enhances the mass activity of atomically dispersed Ru sites but also improves the diffusion efficiency of catalytic molecules.Therefore,the excellent activity from atomically dispersed Ru sites and the enhanced diffusion from open hollow structure respectively improve the redox kinetics and cycling stability,ultimately achieving a high-performance lithium–oxygen battery.

关键词： Atomically dispersed Open hollow structure Discharge product Lithium Oxygen battery

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Advances in the application of hydrogel-based scaffolds for tendon repair

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Genes & Diseases 2024年第4期11卷 296-313页

作者： Renqiang chen Fanglin chen Kenian chen Jian Xu Department of Orthopedics The First Affiliated HospitalZhejiang University School of MedicineHangzhouZhejiang 310003China Department of Orthopedics The Fourth Affiliated Hospital of Guangxi Medical UniversityLiuzhou Guangxi 545005China

Tendon injuries often lead to joint dysfunction due to the limited self-regeneration capacity of tendons.Repairing tendons is a major challenge for surgeons and imposes a signif-icant financial burden on society.Therefore,there is an urgent need to develop effective stra-tegies for repairing injured tendons.Tendon tissue engineering using hydrogels has emerged as a promising approach that has attracted considerable interest.Hydrogels possess excellent biocompatibility and biodegradability,enabling them to create an extracellular matrix-like growth environment for cells.They can also serve as a carrier for cells or other substances to accelerate tendon repair.In the past decade,numerous studies have made significant prog-ress in the preparation of hydrogel scaffolds for tendon healing.This review aims to provide an overview of recent research on the materials of hydrogel-based scaffolds used for tendon tis-sue engineering and discusses the delivery systems based on them.

关键词： Application Hydrogel-based Repairscaffolds Review Tendon injury Tissue engineering

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Photodegradation of xylene isomers:Kinetics,mechanism,secondary pollutant formation potential and health risk evaluation

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Journal of Environmental Sciences 2024年第2期136卷 658-669页

作者： Xiaoyan chen Weikun Zhu Sufen Feng Jiangyao chen Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control Guangdong Technology Research Center for Photocatalytic Technology Integration and Equipment EngineeringInstitute of Environmental Health and Pollution ControlGuangdong University of TechnologyGuangzhou 510006China Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and HealthSchool of Environmental Science and EngineeringGuangdong University of TechnologyGuangzhou 510006China

Photodegradation technology has been widely applied in the purification of industrial aromatic hydrocarbons.However,whether this technology efficiently removes the pollutants to prevent secondary pollution and health risk is still unclear.Here,the photodegradation processes of three xylenes were compared under designed reaction atmospheres and light sources.Xe lamp showed poor photodegradation ability toward xylenes,no matter in N_(2) or N_(2)+O_(2)system,while much higher photodegradation performance of xylenes were obtained under ultraviolet(UV)and vacuum ultraviolet(VUV)irradiation,especially in N_(2)+O_(2)+VUV system,where 97.9%of m-xylene,99.0%of o-xylene or 87.5%of p-xylene with the initial concentration of 860 mg/m^(3) was removed within 240 min.The xylenes underwent three processes of photo-isomerization,photodecomposition and photo-oxidation to produce intermediates of aromatics,alkanes and carbonyls.Among them,the photo-isomerization products showed the highest concentration percentage(e.g.,≥50%in o-xylene system),confirming that photo-isomerization reaction was the dominated photodegradation process of xylenes.Moreover,these isomerized products not only contributed about 97%and91%to the formation potential of O3(OFP)and secondary organic aerosols(SOAFP),but also displayed obvious non-carcinogenic risk,although one of photodecomposition product—benzene showed the highest occupational exposure risk.Therefore,the secondary pollution and health risks of photodegradation products of xylenes were non-ignorable,although the OFP,SOAFP and health risks of the generated products reduced at least 4.5 times in comparison with that of the degraded xylenes.The findings are helpful for the appropriate application of this technology in the purification of industrial organic waste gas.

关键词： Isomer aromatics Photodegradation Ozone formation Secondary organic aerosols Health risk

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Isotopic characteristics and source analysis of atmospheric ammonia during agricultural periods in the Xichuan area of the Danjiangkou Reservoir

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Journal of Environmental Sciences 2024年第2期136卷 460-469页

作者： Xiaoshu chen Tongqian Zhao Chunyan Xiao Xiaoming Guo Feihong chen Institute of Resources and Environment Henan Polytechnic UniversityJiaozuo 454000China

Nitrogen deposition is an important means of exogenous nitrogen input in reservoir water.Agricultural activities around the reservoir lead to a sharp increase in the concentration of ammonia in the atmosphere,which poses a threat to the reservoir water body.Clarifying the contribution of agricultural ammonia release to atmospheric NH_(x)(gaseous NH_(3)and particulate NH_(4)^(+)),in the reservoir area can provide a theoretical foundation for local reactive nitrogen control.We collected atmospheric NH_(3)and NH_(4)^(+)samples during the agricultural periods and analyzed the isotopic characteristics of atmospheric NH_(x)and the contribution rates of different ammonia sources in the Xichuan area of the Danjiangkou Reservoir.The results showed that the initialδ~(15)N values of NH_(3)(-30.0‰to–7.2‰)and particulate NH_(4)^(+)(–33‰to+4.9‰for finer and coarser particles,respectively)are different,and their contribution ratios from dissimilar ammonia sources are also different,among which NH_(4)^(+)is more susceptible to meteorological factors.However,since the atmospheric NH_(x)in the Xichuan area is mainly gaseous NH_(3),the final sources of atmospheric ammonia nitrogen source depend on gaseous NH_(3).Agricultural sources(59%-74%)were the main NH_(3)sources in this area.Among them,the fertilizer use emission was dominant;it had the highest contribution rate in summer during the agricultural period and a more prominent impact in areas with less human interference.Reasonable regulation of the application of high-ammonia releasing fertilizer,especially during the agricultural period in summer,is an effective way to reduce the threat of atmospheric ammonia to water health.

关键词： Danjiangkou reservoir Atmospheric ammonia nitrogen Isotope Ammonia source analysis Agricultural sources

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Meridional deflection of global eddy propagation derived from tandem altimetry: Mechanism and implication

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Science China Earth Sciences 2024年第3期67卷 811-825页

作者： Ge chen Xiaoyan chen Frontiers Science Center for Deep Ocean Multispheres and Earth System School of Marine TechnologyOcean University of ChinaQindao 266100China Laboratory for Regional Oceanography and Numerical Modeling Laoshan LaboratoryQindao 266237China

A common view on meridional deflection of eddy propagation is poleward for cyclones and equatorward for anticyclones. This widely accepted polarity-sensitive pattern has been increasingly undermined given that it is systematically violated on both zonal and regional scales as recently reported. Here, we approach the problem by exploring these violations in terms of eddy effects of spatiotemporal geostrophy, thermal fading, and flow dragging, yielding the following main conclusions.(1) The polarity-dependent deflection discrepancy is a pseudo feature resulting from a biased fit to the normalized eddy tracks which are spatially asymmetric(though azimuthally symmetric) between the two signs;Instead, the primary pattern of eddy deflection appears to be geographically correlated and polarity independent.(2) Geostrophic adjustment plays a critical role in defining the meridional movement of an eddy. Specifically, a consistent poleward(equatorward) trajectory bending of spatially(temporally) ageostrophic eddies is observed irrespective of their polarity.(3) The mechanism of eddy deflection is also determined by its zonal propagation direction. Westward propagating eddies are substantially affected by thermal fading, while opposite ones by flow dragging. A realistic and comprehensive understanding of eddy deflection mechanisms serves as a significant contribution to the prediction of eddy trajectory, and the protection of ocean environment.

关键词： Mesoscale eddies Eddy propagation Eddy meridional deflection Satellite observation Geostrophic adjustment

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