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A three-dimensional variational ocean data assimilation system:Scheme and preliminary results

Science china Earth Sciences 2006年第11期49卷 1212-1222页

作者： ZHU Jiang1,2, ZHOU Guangqing1, YAN Changxiang1, FU Weiwei1 & YOU Xiaobao1,3.1. International Center for Climate and Environment Sciences, institute of Atmospheric Physics, Chinese Academy of Sciences, beijing 100029, china 2. Jiangsu Key Laboratory of Meteorological Disaster, Nanjing University of Information Science and Technology, Nanjing 210044, china 3. beijing institute of applied meteorology, beijing 100029, china International Center for Climate and Environment Sciences Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Jiangsu Key Laboratory of Meteorological Disaster Nanjing University of Information Science and Technology Nanjing China beijing institute of applied {3. Beijing China

A new 3.VAR-based Ocean Variational Analysis System (OVALS) is developed. OVALS is capable of assimilating in situ sea water temperature and salinity observations and satellite altimetry data. As a component of OVALS, a new variational scheme is proposed to assimilate the sea surface height data. This scheme considers both the vertical correlation of background errors and the nonlinear temperature-salinity relationship which is derived from the generalization of the linear balance constraints to the nonlinear in the 3.VAR. By this scheme, the model temperature and salinity fields are directly adjusted from the altimetry data. Additionally, OVALS can assimilate the temperature and salinity profiles from the ARGO floats which have been implemented in recent years and some temperature and salinity data such as from expendable bathythermograph, moored ocean buoys, etc. A 21-year assimilation experiment is carried out by using OVALS and the Tropical Pacific circulation model. The results show that the assimilation system may effectively improve the estimations of temperature and salinity by assimilating all kinds of observations. Moreover, the root mean square errors of temperature and salinity in the upper depth less than 420 m reach 0.63. and 0.3. psu.

关键词： data assimilation, 3.VAR, sea surface height, ARGO floats.

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Recommendation Method for Contrastive Enhancement of Neighborhood Information

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Computers, Materials & Continua 2024年第1期78卷 453-472页

作者： Hairong Wang beijing Zhou Lisi Zhang He Ma School of Computer Science and Engineering North Minzu UniversityNingxia750021China

Knowledge graph can assist in improving recommendation performance and is widely applied in various person-alized recommendation ***,existing knowledge-aware recommendation methods face challenges such as weak user-item interaction supervisory signals and noise in the knowledge *** tackle these issues,this paper proposes a neighbor information contrast-enhanced recommendation method by adding subtle noise to construct contrast views and employing contrastive learning to strengthen supervisory signals and reduce knowledge ***,first,this paper adopts heterogeneous propagation and knowledge-aware attention networks to obtain multi-order neighbor embedding of users and items,mining the high-order neighbor informa-tion of users and ***,in the neighbor information,this paper introduces weak noise following a uniform distribution to construct neighbor contrast views,effectively reducing the time overhead of view *** paper then performs contrastive learning between neighbor views to promote the uniformity of view information,adjusting the neighbor structure,and achieving the goal of reducing the knowledge noise in the knowledge ***,this paper introduces multi-task learning to mitigate the problem of weak supervisory *** validate the effectiveness of our method,experiments are conducted on theMovieLens-1M,MovieLens-20M,Book-Crossing,and Last-FM *** results showthat compared to the best baselines,our method shows significant improvements in AUC and F1.

关键词： Contrastive learning knowledge graph recommendation method

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On the periodic solutions of a type of differential-iterative equations

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Chinese Science Bulletin 1998年第3期43卷 204-206页

作者： GE Weigao 1, LIU Zhengrong 2 and YU Yuanhong 3.1. Department of applied Mathematics, beijing institute of Technology, beijing 100081, china 2. Department of Mathematics, Yunnan University, Kunming 650091, china 3. institute of applied Mathematics, C Department of applied Mathematics Beijing Institute of Technology Beijing China Department of Mathematics Yunnan University Kunming China institute of applied Mathematics Chinese Academy of Sciences Beijing China

Sufficient conditions for the existence of periodic solutions to a type of nonautonomous differential_iterative equations are given.

关键词： differential_iterative equation periodic solution fixed point.

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Statistical Characteristics of Metastable Pitting of 3.6 Stainless Steel

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Journal of Materials Science & Technology 2000年第3期16卷 286-290页

作者： Yu ZUO, Haiou DU and Jinping XIONG (Dept. of applied Chemistry, beijing University of Chemical Technology, beijing 100029,{3.) Dept. of applied Chemistry Beijing University of Chemical Technology Beijing 100029 China

The statistical characteristics of the current fluctuations during metastable pitting of 3.6L stainless steel in NaCI solution were studied using potentiostatic method. The growth rates and peak currents of metastable pits followed log-normal distributions. As potential and chloride concentration increased, both growth rate and peak current of metastable pits increased. The lifetime of metastable pits also followed log-normal distribution, and was almost not affected by potential. Higher growth rates did not definitely result in larger metastable pits. A certain propagation rate range was found beneficial for the micropit to remain growth. At constant potential, the maximum peak currents in different time intervals during a potentiostatic test followed extreme distribution. The statistical characteristics of metastable pitting may be used to predict the tendency of pitting corrosion.

关键词： Statistical Characteristics of Metastable Pitting of 3.6 Stainless Steel

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^(40)Ar/^(3.)Ar dating of shear deformation of the Xianshuihe fault zone in west Sichuan and its tectonic significance

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Science china Earth Sciences 2004年第9期47卷 794-803页

作者： ZHANG Yueqiao1, CHEN Wen2, 3.& YANG Nong1 1. institute of Geomechanics, Chinese Academy of Geological Sciences, beijing 100081, china 2. institute of Geology, Chinese Academy of Geological Sciences, beijing 10003., china 3. institute of Geology and Geophysics, Chinese Academy of Sciences, beijing 100029, china institute of Geomechanics Chinese Academy of Geological Sciences Beijing China institute of Geology Chinese Academy of Geological Sciences Beijing China institute of Geology and Geophysics Chinese Academy of Sciences Beijing China

Based on field geological survey, structural measurements and classical Ar/Ar dating of mica, biotite and K-feldspar, we obtain cooling ages for Miocene left-lateral shear along the Xianshuihe fault zone. The results document two thermal events during the sinistral shear. The early event (12-10 Ma) corresponds to rapid cooling of the Zheduoshan granitic massif from above 700℃ to below 3.0℃. The late event (5-3.5 Ma) corresponds to cooling of granites intruded along the eastern side of the fault zone. These dating results provide important thermochronological constraint on the timing of late Cenozoic eastward extrusion of the Chuan-Dian Block in the SE Tibetan margin.

关键词： Xianshuihe fault zone, Zheduoshan granitic massif, sinistral shear deformation, 40Ar/3.Ar dating, late Cenozoic.

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A new DNA algorithm to solve graph coloring problem

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Progress in Natural Science:Materials International 2007年第6期17卷 733-738页

作者： Jiang Xingpeng1, Li Yin2, Meng Ya3.and Meng Dazhi2(1. National Laboratory of Pattern Recognition,institute of Automation, Chinese Academy of Sciences, beijing 100080, china 2. College of {3. Sciences, beijing University of Technology, beijing 100022, china 3. School of Science, beijing institute of Technology, beijing 100081, china) National Laboratory of Pattern Recognition Institute of Automation Chinese Academy of Sciences Beijing 100080 China National High Magnetic Field Laboratory Florida State University 1800 East Paul Dirac Drive Tallahassee Florida 32306 USA

Using a small quantity of DNA molecules and little experimental time to solve complex problems successfully is a goal of DNA computing. Some NP-hard problems have been solved by DNA computing with lower time complexity than conventional computing. However, this advantage often brings higher space complexity and needs a large number of DNA encoding molecules. One example is graph coloring problem. Current DNA algorithms need exponentially increasing DNA encoding strands with the growing of problem size. Here we propose a new DNA algorithm of graph coloring problem based on the proof of four-color theorem. This algorithm has good properties of needing a relatively small number of operations in polynomial time and needing a small number of DNA encoding molecules (we need only 6R DNA encoding molecules if the number of regions in a graph is R).

关键词： DNA computing NP-hard problem graph coloring problem.

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Progress and review of the studies on the end-Triassic mass extinction event

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Science china Earth Sciences 2005年第12期48卷 2049-2060页

作者： DENG Shenghui1,2, LU Yuanzheng1,2,3.& XU Daoyi4 1. Research institute of Petroleum Exploration and Development, beijing 100083. china 2. Key Laboratory of Oil and Gas Reservoir of Petro{3., beijing 100083. china 3. china University of Geosciences, beijing 100083. china 4. institute of Geology, china Earthquake Administration, beijing 100029, china Research institute of Petroleum Exploration and Development Beijing China Key Laboratory of Oil and Gas Reservoir of Petrochina Beijing China china University of Geosciences Beijing China institute of Geology China Earthquake Administration Beijing China

The mass extinction at the end-Triassic is one of the five biggest in the Phanerozoic. However,it is the least well understood among these five events, and only till last decade it became a great academic interesting subject to geologists. The evidences for this event come obviously from bivalves, brachiopods, ammonites, corals, radiolaria, ostracods and foraminifera of marine habitats, and plants and tetrapods of terrestrial realm. By contrast, for some of other groups, such as marine gastropods and marine vertebrates, no mass extinction has been recog-nized yet. The extinction event is strongly marked at specific level but shown a complicated situa-tion at generic and family levels. Dramatic changing of the environment, such as the temperature raise due to the greenhouse effect, the marine anoxic habitats caused by a sudden transgression after the regression at the end of Triassic, has been claimed to be the main cause of the extinction. Many hypotheses have been suggested to demonstrate the mechanisms of the environment changing, among which two popular ones are the bolide impact and volcanic eruption. The Triassic-Jurassic (Tr-J) boundary mass extinction event is still poorly understood because no enough data have been obtained from the Tr-J boundary successional sections of both marine and terrestrial sediments, and most of these studies were regionally restricted. The basic aspects of the event and its associated environmental conditions remain poorly characterized and the causal mechanism or mechanisms are equivocal. Some authors even doubt its occurrence. china has many successionally developed terrestrial and marine Tr-J sections. Detailed studies of these sections may be important and significant for well understanding of the event.

关键词： progress, review, end-Triassic, mass extinction, mechanism, Tr-J boundary.

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New progress in the principle of nonequilibrium statistical physics

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Chinese Science Bulletin 2001年第6期46卷 448-454页

作者： XING XiusanDepartment of applied Physics, beijing institute of Technology, beijing 100081, china Department of applied Physics Beijing Institute of Technology Beijing China

In recent years, a new fundamental equation of nonequilibrium statistical physics was proposed in place of the Liouville equation. That is the anomalous Langevin equation in (?) space or its equivalent Liouville diffusion equation of time-reversal asymmetry. This equation reflects that the form of motion of particles in statistical thermody-namic systems has the drift-diffusion duality and the law of motion of statistical thermodynamics is stochastic in essence, but does not obey the Newton equation of motion, though it is also constrained by dynamics. The stochastic diffusion of the particles is the microscopic origin of macroscopic irre-versibility. Starting from this equation, the BBGKY diffusion equation hierarchy was presented, the hydrodynamic equations, such as the generalized Navier-Stokes equation, the mass drift-diffusion equation and the thermal conductivity equation have been derived succinctly. The unified description of all three level equations of microscopic, kinetic and hydrodynamic

关键词： anomalous Langevin equation in space drift-diffusion duality stochastic law nonequilibrium entropy evolution equation entropy diffusion.

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Rheological Behaviour for Polymer Melts and Concentrated SolutionsPart Ⅱ: Material Function with Nagai Chain Constraints and Determination of Their Parameters from Flow Curves

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Journal of Materials Science & Technology 1995年第2期11卷 141-152页

作者： Mingshi SONG Sizhu WU and Xiuyun DU(Research institute of Polymeric Materials, beijing University of Chemical Technology, beijing, {3., china) beijing Univ of Chemical Technology Beijing China

An integral constitutive equation and a set of material functions for describing the strain history of polymer melts were formulated in terms of the Cauchy-Green and Finger tensors. A simple memory function and the dependence of ηo and τt on M3.4 were derived from the theory of non-linear viscoelasticity with constraints of entanglements for polymer melts and substituted into the Oldroye-Walters-Fredickson constitutive equation. An integral constitutive equation for polymer melts was consequently obtained. Some material functions of the constitutive equation related to certain 'test flow' are examined as follows : (1) simple steady shear flow; (2) steady elongation flow; (3. small-amplitude oscillatory shear flow; (4) stress growth upon the inception of steady shear elongation flow; (5) stress relaxation (modulus and compllance). These theoretical relations for simple steady shear flow were compared with experimental data from our laboratory and references for various polymer melts and concentrated solutions. A good agreement between the theory and experiment was achieved.

关键词： LDPE Material Function with Nagai Chain Constraints and Determination of Their Parameters from Flow Curves Rheological Behaviour for Polymer Melts and Concentrated SolutionsPart Flow GR

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Zonal propagation of kinetic energy and convection in the South china Sea and Indian monsoon regions in boreal summer

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Science china Earth Sciences 2004年第12期47卷 1076-1084页

作者： CHEN Longxun 1 ,GAO Hui 2 ,HE Jinhai 2 ,TAO Shiyan 3.& JIN Zuhui 3.1.Chinese Academy of Meteorological Sciences,beijing 100081,china 2.Nanjing institute of {3.,Nanjing 210044,china 3.institute of Atmospheric Physics,Chinese Academy of Sciences,beijing 100029,china Chinese Academy of Meteorological Sciences Beijing China Nanjing institute of meteorology Nanjing China Chinese Academy of Sciences Institute of Atmospheric Physics Beijing China

Zonal propagation of kinetic energy (KE) and convection in the South china Sea (SCS) and Indian summer monsoon areas are examined in present study. Results suggest that the SCS and Indian summer monsoon prevailed regions (5 —15°N) are dominated by the southwesterly wind, however, the disturbances of KE at 850 hPa and convection are observed mainly coming from the western Pacific Ocean (140—150°E), after passing through the SCS, and westward propagated into the Bay of Bengal (90—100°E). In the Indian summer monsoon domain, where the disturbances of KE are found mainly coming from the Arabian Sea (AS) and eastward propagated into the Bay of Bengal. Therefore, the SCS and the Indian summer mon- soon are quite different in zonal propagation of KE and convection. The SCS summer monsoon is mainly affected by the KE and convection coming from the tropical western Pacific. The Indian summer monsoon, however, can be partly influenced by the AS and the SCS summer monsoon. The analysis also suggests that the interaction region between the SCS and the Indian summer monsoon is around 90—95°E, rather than 105°E as proposed by earlier studies.

关键词： zonal propagation of KE and convection, East Asian monsoon, Indian monsoon.

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