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Science China(Physics,Mechanics & Astronomy) 2008年第6期51卷 577-590页

作者： WANG ShunJin zhang hua Center of Theoretical Physics Sichuan UniversityChengdu 610064China

Using functional derivative technique in quantum field theory, the algebraic dy-namics approach for solution of ordinary differential evolution equations was gen-eralized to treat partial differential evolution equations. The partial differential evo-lution equations were lifted to the corresponding functional partial differential equations in functional space by introducing the time translation operator. The functional partial differential evolution equations were solved by algebraic dynam-ics. The algebraic dynamics solutions are analytical in Taylor series in terms of both initial functions and time. Based on the exact analytical solutions, a new nu-merical algorithm—algebraic dynamics algorithm was proposed for partial differ-ential evolution equations. The difficulty of and the way out for the algorithm were discussed. The application of the approach to and computer numerical experi-ments on the nonlinear Burgers equation and meteorological advection equation indicate that the algebraic dynamics approach and algebraic dynamics algorithm are effective to the solution of nonlinear partial differential evolution equations both analytically and numerically.

关键词： functional partial differential equations exact algebraic dynamics solutions of nonlinear partial differential evolution equations algebraic dynamics algorithm

Algebraic dynamics solutions and algebraic dynamics algorithm for nonlinear ordinary differential equations

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Science China(Physics,Mechanics & Astronomy) 2006年第6期49卷 716-728页

作者： WANG Shunjin zhang hua Center of Theoretical Physics Sichuan UniversityChengdu610064China Center of Theoretical PhysicsSichuan UniversityChengdu610064China

The problem of preserving fidelity in numerical computation of nonlinear or-dinary differential equations is studied in terms of preserving local differential structure and approximating global integration structure of the dynamical system. The ordinary differen-tial equations are lifted to the corresponding partial differential equations in the framework of algebraic dynamics,and a new algorithm——algebraic dynamics algorithm is proposed based on the exact analytical solutions of the ordinary differential equations by the alge-braic dynamics method. In the new algorithm,the time evolution of the ordinary differential system is described locally by the time translation operator and globally by the time evo-lution operator. The exact analytical piece-like solution of the ordinary differential equa-tions is expressd in terms of Taylor series with a local convergent radius,and its finite order truncation leads to the new numerical algorithm with a controllable precision better than Runge Kutta Algorithm and Symplectic Geometric Algorithm.

关键词： exact algebraic dynamics solutions of ordinary differential equations,algebraic dynamics algorithm,preserving fidelity geometrically and dynamically.

Meiofauna distributions at the oxygen minimum zone in Changjiang (Yangtze) River Estuary waters

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Acta Oceanologica Sinica 2006年第5期25卷 120-134页

作者： hua Er zhang Zhinan zhang Yan College of Marine Life Science Ocean University of China Qingdao 266003 China

A quantitative study on meiofauna was carried out along a transect throughout the Changjiang Estuary＇ s oxygen minimum zone （OMZ） in the East China Sea. There exist two distinct station groups in the OMZ： the fine-grained hypoxic area and the more fine-grained anoxie area. Meiofauna abundance ranged from （ 101.5±31.0） ind./cm^2 （ hypoxie area） to （369.9±123.9） ind./cm^2（ anoxic area） along the transect. Free-living marine nematodes were the numerically dominant meiofauna at every station. The anoxic area differed significantly in meiofauna abundance and vertical distribution pattern from the hypoxic area. Within the anoxic area, nematodes abundance increased and amounted to over 90% of the total meiofauna; about 50% of nematodes were found in the 2-5 and 5-8 cm layers. At hypoxie stations, about over 85 % were restricted to the top 2 cm. Benthic eopepod abundance and dominance decreased consistently with the oxygen gradient. The pattern of meiofauna biomass was similar to that of abundance. The correlation analysis of the meiofauna numbers and environmental parameters indicated that abundance and biomass of total meiofauna and nematodes had significant or highly significant （ P 〈 0.05 or P 〈 0.01 ） correlations with Chl a and Pha a, but no significant （ P 〉 0.05 ） correlations with bottom-water oxygen （ BWO2 ）. On the other hand, there was a highly significant positive correlation between benthic eopepod abundance and bottom-water oxygen （P 〈 0.05 ）. The investigation on the nematode community structure indicated that two different nematode communities existed in hypoxic and anoxic areas. In certain way, the shift in nematode species composition distinguishes the anoxia to hypoxia. Nematode diversity was generally lower within the anoxic stations than the hypoxic ones, but the difference was not significant. Indices of the nematode community structure varied in relation to the bottom-water oxygen together with bottom-water temperature, Chl a concentration and median

关键词： meiofauna free-living marine nematodes oxygen minimum zone hypoxia anoxia Changjiang estuary EastChina Sea

A numerical approach to the interaction between airflow and a high-speed train subjected to crosswind

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2013年第7期14卷 482-493页

作者： Tian LI Ji-ye zhang Wei-hua zhang State Key Laboratory of Traction Power Southwest Jiaotong University

Aerodynamic forces and dynamic performances of railway vehicles are coupled and affected by each other. On the one hand, aerodynamic forces change the displacements of a train. On the other hand, displacements affect aerodynamic forces. Based on vehicle-track coupling dynamics and aerodynamics, a numerical approach to the interaction between airflow and a high-speed train is presented in this paper. Aerodynamic forces and dynamic performances of a high-speed train subjected to crosswind were numerically simulated. Results showed that the interaction between airflow and a high-speed train has a significant influence on displacements and aerodynamic forces of the head coach. Therefore, it is necessary to consider the interaction between airflow and a high-speed train subjected to crosswind.

关键词： High-speed train Crosswind Aerodynamics Co-simulation Interaction

Impact of Improving Design Factor over 0.72 on the Safety and Reliability of Gas Pipelines and Feasibility Justification

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Chinese Journal of Mechanical Engineering 2012年第1期25卷 166-172页

作者： ZHAO Xinwei zhang Guangli LUO Jinheng zhang hua Tubular Goods Research Institute of China National Petroleum Corporation Xi’an 710065China Petroleumtubular engineering Key Laboratory of China National Petroleum Corporation Xi’an 710065China

Many years experience of the operation of high stress (>72% specified minimum yield strength, SMYS) gas pipelines and statistical analysis results of pipeline incidents showed that the operating pipelines at stress levels over 72% SMYS have not presented problems in USA and Canada, and design factor does not control incidents or the safety of pipelines. Enhancing pipeline safety management level is most important for decreasing incident rate. The application history of higher design factors in the U.S and Canada was reviewed. And the effect of higher factors to the critical flaw size, puncture resistance, change of reliability with time, risk level and the arrest toughness requirements of pipeline were analyzed here. The comparison of pipeline failure rates and risk levels between two design factors (0.72 and 0.8) has shown that a change in design factor from 0.72 to 0.8 would bring little effect on failure rates and risk levels. On the basis of the analysis result, the application feasibility of design factor of 0.8 in China was discussed and the related suggestions were proposed. When an operator wishes to apply design factor 0.8 to gas pipeline, the following process is recommended: stress level of line pipe hydro test should be up to 100% SMYS, reliability and risk assessment at the design feasibility or conceptual stage should be conducted, Charpy impact energy should meet the need of pipeline crack arrest; and establish and execute risk based integrity management plan. The technology of pipeline steel metallurgy, line pipe fabrication and pipeline construction, and line pipe quality control level in China achieved tremendous progresses, and line pipe product standards and property indexes have come up to international advanced level. Furthermore, pipeline safety management has improved greatly in China. Consequently, the research for the feasibility of application of design factor of 0.8 in China has fundamental basis.

关键词： gas pipeline higher design factor safety and reliability risk integrity management

Structure and Evolution of Decadal Spiciness Variability in the North Pacific during 2004-20,Revealed from Argo Observations

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Advances in Atmospheric Sciences 2022年第6期39卷 953-966页

作者： Guanghui ZHOU Rong-hua zhang CAS Key Laboratory of Ocean Circulation and Waves Institute of Oceanologyand Center for Ocean Mega-ScienceChinese Academy of SciencesQingdao 266071China University of Chinese Academy of Sciences Beijing 100029China Laboratory for Ocean and Climate Dynamics Pilot National Laboratory for Marine Science and TechnologyQingdao 266237China Center for Excellence in Quaternary Science and Global Change Chinese Academy of SciencesXi’an 710061China

Ocean spiciness is referred to as density-compensated temperature and salinity variations with warm(cool)and salty(fresh)waters having high(low)spiciness,*** structure and evolution of density-compensated(warm/salty or cool/fresh)spiciness anomalies are investigated in the North Pacific thermocline using Argo observations during the period *** well-organized decadal spiciness events are identified through isopycnal surface *** warm/salty spiciness anomaly of about 0.15°C and 0.05 g kg^(−1)temperature and salinity perturbations on the 25 kg m^(−1)isopycnal surface appeared in the eastern subtropical North Pacific at(18°-30°N,120°-150°W)in 2007,which then migrated southwestward along the mean circulation and arrived in the western tropics at(~15°N,145°E-175°W)in 2012-13,with the reduced salinity perturbation of about 0.043 g kg^(−1).Another cool/fresh spiciness anomaly of about−0.2°C and−0.07 g kg^(−1)temperature and salinity perturbations originated from the eastern subtropics at(120°-150°W,~30°N)in 2014 and followed a similar advective pathway during the period from 2014-15 to *** subduction pathway can be adequately determined by the mean Montgomery stream function on the isopycnal surface;the propagation direction and speed are in good agreement with the expectation for the role played by advection due to the mean geostrophic ***,the subducted decadal spiciness anomalies can have negative feedback on sea surface temperature(SST)variability in the western tropical Pacific through the diapycnal *** identifications of these density-compensated spiciness anomalies and their propagation pathways provide a clear illustration of the oceanic extratropics-tropics interactions in the North Pacific Ocean.

关键词： isopycnal analysis spiciness anomalies subduction pathway advection role decadal variability North Pacific

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融合注意力的异构信息网络嵌入学习综述

计算机科学与探索 2025年第1期19卷 1-29页

作者：屠佳琪张华常晓洁王佶袁书宏浙江大学信息技术中心杭州310058

近年来,图嵌入学习已成为信息网络分析领域最常用的技术之一,其将网络对象嵌入到低维稠密向量空间的同时保留网络结构和内容特征并应用于下游分析任务。然而大多数现实网络是由多种对象类型、对象间的关系以及对象内容特征所组成的异构... 详细信息

近年来,图嵌入学习已成为信息网络分析领域最常用的技术之一,其将网络对象嵌入到低维稠密向量空间的同时保留网络结构和内容特征并应用于下游分析任务。然而大多数现实网络是由多种对象类型、对象间的关系以及对象内容特征所组成的异构信息网络(HIN)。因此为了学习更有效的嵌入表达,研究者开始将注意力机制融入到异构信息网络嵌入学习中,用以区分不同层面的异构性对嵌入表达的影响程度。对现有融合注意力的异构信息网络嵌入模型进行综述,全面回顾异构信息网络嵌入在过去五年的研究历程,总结其在解决网络异构性时所面临的内容异构性、结构异构性与语义异构性三大挑战,并概括出一种通用的注意力融合模型框架;针对上述挑战,将现有注意力融合方式分为基于元路径、基于图神经网络以及面向应用场景三大类,并详细对比阐述了各类代表性模型;介绍常用的数据集、基准平台工具和评测指标;总结和探讨异构信息网络嵌入学习未来的研究方向。

关键词：异构信息网络图嵌入学习注意力机制元路径图神经网络

A Hybrid Neural Network Model for ENSO Prediction in Combination with Principal Oscillation Pattern Analyses

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Advances in Atmospheric Sciences 2022年第6期39卷 889-902页

作者： Lu ZHOU Rong-hua zhang CAS Key Laboratory of Ocean Circulation and Waves Institute of Oceanologyand Center for Ocean Mega-ScienceChinese Academy of SciencesQingdao 266071China University of Chinese Academy of Sciences Beijing 100029China Laboratory for Ocean and Climate Dynamics Pilot National Laboratory for Marine Science and TechnologyQingdao 266237China Center for Excellence in Quaternary Science and Global Change Chinese Academy of SciencesXi’an 710061China

El Niño-Southern Oscillation(ENSO)can be currently predicted reasonably well six months and longer,but large biases and uncertainties remain in its real-time *** approaches have been taken to improve understanding of ENSO processes,and different models for ENSO predictions have been developed,including linear statistical models based on principal oscillation pattern(POP)analyses,convolutional neural networks(CNNs),and so ***,we develop a novel hybrid model,named as POP-Net,by combining the POP analysis procedure with CNN-long short-term memory(LSTM)algorithm to predict the Niño-3.4 sea surface temperature(SST)*** predictions are compared with each other from the corresponding three models:POP model,CNN-LSTM model,and POP-Net,*** POP-based pre-processing acts to enhance ENSO-related signals of interest while filtering unrelated ***,an improved prediction is achieved in the POP-Net relative to *** POP-Net shows a high-correlation skill for 17-month lead time prediction(correlation coefficients exceeding 0.5)during the 1994-2020 validation *** POP-Net also alleviates the spring predictability barrier(SPB).It is concluded that value-added artificial neural networks for improved ENSO predictions are possible by including the process-oriented analyses to enhance signal representations.

关键词： ENSO prediction the principal oscillation pattern(POP)analyses neural network a hybrid approach

U-Net Models for Representing Wind Stress Anomalies over the Tropical Pacific and Their Integrations with an Intermediate Coupled Model for ENSO Studies

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Advances in Atmospheric Sciences 2024年第7期41卷 1403-1416页

作者： Shuangying Du Rong-hua zhang Key Laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of SciencesQingdao266071China School of Marine Sciences Nanjing University of Information Science and TechnologyNanjing210044China Laosan Laboratory Qingdao266237China University of Chinese Academy of Sciences Beijing100049China

El Niño-Southern Oscillation(ENSO)is the strongest interannual climate mode influencing the coupled ocean-atmosphere system in the tropical Pacific,and numerous dynamical and statistical models have been developed to simulate and predict *** some simplified coupled ocean-atmosphere models,the relationship between sea surface temperature(SST)anomalies and wind stress(τ)anomalies can be constructed by statistical methods,such as singular value decomposition(SVD).In recent years,the applications of artificial intelligence(AI)to climate modeling have shown promising prospects,and the integrations of AI-based models with dynamical models are active areas of *** study constructs U-Net models for representing the relationship between SSTAs andτanomalies in the tropical Pacific;the UNet-derivedτmodel,denoted asτUNet,is then used to replace the original SVD-basedτmodel of an intermediate coupled model(ICM),forming a newly AI-integrated ICM,referred to as *** simulation results obtained from ICM-UNet demonstrate their ability to represent the spatiotemporal variability of oceanic and atmospheric anomaly fields in the equatorial *** the ocean-only case study,theτUNet-derived wind stress anomaly fields are used to force the ocean component of the ICM,the results of which also indicate reasonable simulations of typical ENSO *** results demonstrate the feasibility of integrating an AI-derived model with a physics-based dynamical model for ENSO modeling ***,the successful integration of the dynamical ocean models with the AI-based atmospheric wind model provides a novel approach to ocean-atmosphere interaction modeling studies.

关键词： U-Net models wind stress anomalies ICM integration of AI and physical components

The Symbolic Extension Theory in Topological Dynamics

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Acta Mathematica Sinica,English Series 2022年第1期38卷 107-136页

作者： Tomasz DOWNAROWICZ Guo hua zhang Faculty of Pure and Applied Mathematics Wroclaw University of Science and TechnologyWybrze˙ze Wyspia′nskiego 2750-370 WroclawPoland School of Mathematical Sciences and Shanghai Center for Mathematical Sciences Fudan UniversityShanghai 200433P.R.China

In this survey we will present the symbolic extension theory in topological dynamics,which was built over the past twenty years.

关键词： Symbolic extension (symbolic)extension entropy function entropy structure superenvelope principal extension asymptotic h-expansiveness amenable group F?lner sequence tiling system quasi-symbolic extension residually finite group comparison property subexponential group