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A model study on carbon cycle and phytoplankton dynamical processes in the Bohai Sea

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Acta oceanologica Sinica 2003年第1期22卷 47-56页

作者： WeiHao ZhaoLiang FengShizuo InstituteofPhysicaloceanography OceanUniversityofChina(OceanUniversityofQingdao)Qingdao266003China PhysicaloceanographyKeyLabofStateEducationMinistry OceanUniversityofChina(OceanUnivrsityofQingdao)Qingdao266003China

The carbon cycle of lower trophic level in the Bohai Sea is studied with a three-dimensional biological and physical coupled model. The influences of the processes (including horizontal advection, river nutrient load, active transport etc. ) on the phytoplankton biomass and its evolution are estimated. The Bohai Sea is a weak sink of the CO2 in the atmosphere. During the cycle, 13.7% of the gross production of the phytoplankton enter the higher trophic level and 76.8 % of it are consumed by the respiration itself. The nutrient reproduction comes mainly from the internal biogeochemical loop and the rem-ineralization is an important mechanism of the nutrient transfer from organic form to inorganic. Horizontal advection decreases the total biomass and the eutrophication in some sea areas. Change in the nutrient load of a river can only adjust the local system near its estuary. Controlling the input of the nutrient, which limits the alga growth, can be very useful in lessening the phytoplankton biomass.

关键词： Carbon cycle phytoplankton dynamics the Bohai Sea

Boundary conditions for the bending of a piezoelectric beam

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Science china(Physics,Mechanics & Astronomy) 2008年第7期51卷 847-856页

作者： GAO Yang1, XU SiPeng2 & ZHAO BaoSheng3 1 College of Science, china Agricultural university, Beijing 100083, china 2 College of Engineering, ocean university of china, qingdao 2.6071, china 3 school of Mechanical Engineering, university of Science and Technology Liaoning, Anshan 114044, china 1. College of Science China Agricultural University Beijing 100083 China 2. College of Engineering Ocean University of China Qingdao 266071 China 3. school of Mechanical Engineering University of Science and Technology Liaoning Anshan 114044 China

For beam bending in transversely isotropic piezoelectric media, the reciprocal theorem and the general solution of piezoelasticity are applied in a novel way to obtain the appropriate stress and mixed boundary conditions accurate to all orders for the beam of general edge geometry and loadings. By generalizing the method developed by Gregory and Wan, a set of necessary conditions on the edge-data for the existence of a rapidly decaying solution is established. The prescribed edge-data of the beam must satisfy these conditions in order that they could generate a decaying state within the beam. When stress and mixed conditions are imposed on the beam edge, these decaying state conditions for the case of bending deformation of piezoelectric beam are derived explicitly. They are then used for the correct formulation of boundary conditions for the beam theory solution (or the interior solution). Besides, an analytical solution of elastic beam is formulated to verify validity of our boundary conditions. For the stress data, our boundary conditions coincide with those obtained in conventional forms of beam theories. More importantly, the appropriate boundary conditions with two sets of mixed edge-data are obtained for the first time.

关键词： boundary conditions beam bending piezoelectric media decaying states regular states

Mixed boundary conditions for piezoelectric plates

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Science china(Physics,Mechanics & Astronomy) 2009年第5期52卷 755-761页

作者： GAO Yang 1 ,XU SiPeng 2 &ZHAO BaoSheng 3 1College of Science,china Agricultural university,Beijing 100083,china 2College of Engineering,ocean university of china,qingdao 2.6071.china 3 school of Mechanical Engineering,university of Science and Technology of Liaoning,Anshan 114044,china College of Science China Agricultural University Beijing 100083 China College of Engineering Ocean University of China Qingdao 266071 China school of Mechanical Engineering University of Science and Technology of Liaoning Anshan 114044 China

For plate bending and stretching problems in piezoelectric materials,the reciprocal theorem and the general solution of piezoelasticity are applied in a novel way to obtain the appropriate mixed boundary conditions accurate to all order.A decay analysis technique is used to establish necessary conditions that the prescribed data on the edge of the plate must satisfy in order that it should generate a decaying state within the *** the case of axisymmetric bending and stretching of a circular plate,these decaying state conditions are obtained explicitly for the first time when the mixed conditions are imposed on the plate *** are then used for the correct formulation of boundary conditions for the interior solution.

关键词： boundary conditions piezoelectric plates mixed data bending problems stretching problems

On exactness and unbiasedness of confidence bands for a continuous distribution function

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Science china Mathematics 2010年第10期53卷 2665-2678页

作者： DING XiaoBo1,2,XU XingZhong2 & ZHAO ShuRan3 1Institute of Applied Mathematics,Academy of Mathematics and Systems Science,Chinese Academy of Sciences,Beijing 100190,china 2Department of Mathematics,Beijing Institute of Technology,Beijing 100081,china 3school of economics,ocean university of china,qingdao 2.6071.china 1. Institute of Applied Mathematics Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China2. Department of Mathematics Beijing Institute of Technology Beijing 100081 China3. School of Economics Ocean University of China Qingdao 266071 China

We define a class of confidence bands for distribution functions,named simple confidence *** class of bands includes the common step bands and continuous bands,some of which may perform better than the smoothed bands not belonging to the class,e.g.,the kernel smoothed *** is shown that under some mild assumptions,the simple bands with exact coverage for continuous distribution functions are all step *** unbiasedness problem of the step bands is also *** is proved that most of two-sided step bands are biased and one-sided step bands are unbiased.

关键词： exact coverage goodness of fit kernel smoothing simple confidence bands unbiasedness

The Statistical Distribution of the Horizontal Velocities of Water Particles at Wave Surface Maxima

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china ocean Engineering 1998年第3期13卷 359-364页

作者： GUAN Changlong Professor, Institute of Physical oceanography, ocean university of qingdao, qingdao 266003, china. Institute of Physical oceanography Ocean University of Qingdao Qingdao 266003 China

On the basis of the linear model of random sea waves presented by Longuet-Higgins, the statistical distribution of the horizontal velocities of water particles at wave surface maxima is derived theoretically. The derived distribution is similar to that of wave surface maxima, and a new spectral width epsilon(u), which is defined as (1 - m(3)(2)/m(2)m(4))(1/2), is introduced in the distribution. When epsilon(u) tends to zero, the distribution is reduced to Rayleigh distribution and it is reduced to the normal distribution when epsilon(u) tends to unity. For a narrow spectrum, it is proved that epsilon is equal to 1/2 epsilon, where epsilon is (1 - m(2)(2)/m(0)m(4))(1/2) and is the commonly used spectral width.

关键词： sea wave wave surface maxima horizontal velocity statistical distribution

构建社会主义现代化强国的高水平市场经济体制

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改革 2024年第6期 30-39页

作者：中国人民大学经济学院课题组中国人民大学经济学院中国人民大学国家发展与战略研究院中国人民大学农业与农村发展学院

改革开放是决定当代中国命运、大踏步赶上时代的关键一招,更是推进中国式现代化、实现中华民族伟大复兴的关键一招。新形势下,面对国际国内诸多历史性挑战,只有坚定不移全面深化改革开放、建立现代化经济体系,才能破除体制机制障碍,激... 详细信息

改革开放是决定当代中国命运、大踏步赶上时代的关键一招,更是推进中国式现代化、实现中华民族伟大复兴的关键一招。新形势下,面对国际国内诸多历史性挑战,只有坚定不移全面深化改革开放、建立现代化经济体系,才能破除体制机制障碍,激发经济发展新动能,延续经济增长与追赶势头,为中国式现代化建设提供充满生机活力的制度保障。进一步全面深化改革的总目标是完善和发展中国特色社会主义制度,推进国家治理体系和治理能力现代化。建立支撑建设社会主义现代化强国的高水平社会主义市场经济体制,亟须聚焦基本经济制度、高标准市场体系、政府和市场关系、科技创新体制、数字经济发展机制、高水平开放型经济体制、共同富裕实现机制、城乡融合与乡村振兴体制八大重点领域,推动体制机制创新。在进一步全面深化改革中,寻求改革、发展与稳定之间的平衡,处理好政治与经济、增长与收缩、秩序和活力、体制转型与风险防范、发展和安全、中国和世界六大关系。

关键词：中国式现代化经济体制改革全面深化改革

A PRICE-SETTING NEWSVENDOR MODEL UNDER CVAR DECISION CRITERION WITH EMERGENCY PROCUREMENT

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Journal of Systems Science and Systems Engineering 2010年第1期19卷 85-104页

作者： Minghui XU school of economics and Management,Wuhan university,Wuhan 430072,china school of economics and Management Wuhan University Wuhan China

In this paper, we consider a newsvendor model in which a risk-averse manager faces a stochastic price-dependent demand in either an additive or a multiplicative form. An emergency purchase option is allowed after the realization of demand to satisfy the units that are short. By adopting Conditional value-at-risk （CVaR） as the decision criterion, we aim to investigate the optimal pricing and ordering decisions, and the effects of parameter changes in such a setting. We provide sufficient conditions for the uniqueness of the optimal policy for both demand models. We perforl~, comparative statics analysis to show how the optimal pricing and ordering decision behaves when changing parameters. We also compare our results with those of the newsvendor with a general utility function and with CVaR criterion under lost sales assumption. Our key results include：（i） For both demand models, the optimal selling price is decreasing in risk aversion. Hence, the optimal price of a risk-averse newsvendor is not greater than the optimal price of a risk-neutral newsvendor. （it） In contrary to the lost sales case, for the multiplicative demand model, the optimal order quantity may not be monotonic in risk aversion. Consequently, the optimal risk-averse order quantity may be lower or higher than the optimal risk- neutral counterpart. （iii） For the additive model, the optimal order quantity is strictly increasing in the emergency purchase price, while for the multiplicative model the optimal order quantity has no such a monotonic property. Some numerical examples are conducted to verify our claims and gain more insights about the risk-averse decision-making behaviors.

关键词： Newsvendor model inventory pricing risk aversion conditional value-at-risk

The advancement of oscillation theory of functional differential equations

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Chinese Science Bulletin 1998年第12期43卷 974-982页

作者： ZHANG Binggen Department of Applied Mathematics, ocean university of qingdao, qingdao 266003, china Department of Applied Mathematics Ocean University of Qingdao Qingdao China

The oscillation theory of functional differential equations (FDEs) is surveyed including (ⅰ) formulation of oscillation problems; (ⅱ) a brief history of the oscillation theory of FDEs; (ⅲ) main topics in the oscill... 详细信息

关键词： functional differential equations oscillation theory.

Bubble size distribution in surface wave breaking entraining process

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Science china Earth Sciences 2007年第11期50卷 1754-1760页

作者： HAN Lei1,2 & YUAN YeLi2 1 Department of ocean Environment, ocean university of china, qingdao 266003, china 2 The First Institute of oceanography, State ocean Administration, qingdao 266061, china 1. Department of ocean Environment Ocean University of China Qingdao 266003 China 2. The First Institute of oceanography State Ocean Administration Qingdao 266061 China

From the similarity theorem, an expression of bubble population is derived as a function of the air en-trainment rate, the turbulent kinetic energy (TKE) spectrum density and the surface tension. The bubble size spectrum that we obtain has a dependence of a?2.5+nd on the bubble radius, in which nd is positive and dependent on the form of TKE spectrum within the viscous dissipation range. To relate the bubble population with wave parameters, an expression about the air entrainment rate is deduced by intro-ducing two statistical relations to wave breaking. The bubble population vertical distribution is also derived, based on two assumptions from two typical observation results.

关键词： wave breaking,bubble cloud,bubble size spectrum