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CONVERGENCE OF AN EXPLICIT UPWIND FINITE ELEMENT METHOD TO MULTI-DIMENSIONAL CONSERVATION LAWS

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Journal of Computational Mathematics 2001年第1期19卷 87-100页

作者： Jin-chao xu Lung-an ying Center for Computational Mathematics and Applications and Department of Mathematics Pennsylvania State UniversityU.S.A School of Mathematical Sciences Peking UniversityBeijing 100871China

Investigates the convergence of an explicit upwind finite element method, the edge-averaged finite element method to multidimensional scalar conservation laws. Discussion on the finite element scheme and main converge... 详细信息

关键词： conservation law finite element method convergence

NUMERICAL SIMULATION OF DEFORMATION BEHAVIOR OF 22MnB5 BORON STEEL AT ELEVATED TEMPERATURES AND EXPERIMENTAL VERIFICATION

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Acta Mechanica Solida Sinica 2014年第6期27卷 579-587页

作者： dan Zhao Yiguo Zhu Liang ying Ping Hu ying Chang Wanxi Zhang State Key Laboratory of Structural Analysis for Industrial Equipment Faculty of Vehicle Engineering and Mechanics Dalian University of Technology

The effects of strain, strain rate and temperature on the mechanical behavior of 22MnB5 boron steel deformed isothermally under uniaxial tension tests and the experimental characterization of 22MnB5 boron steel in the austenitic region have been investigated. Based on the crystal plasticity theory and thermal kinematics, an improved integration model is presented. In this model, the elastic deformation gradient is the integration variable of the governing equation, which contains not only the elastic deformation but also the thermal effects. In the coupled thermo- mechanical process, this model can reveal the evolution of microstructures such as the rotation of a single crystal and the slip systems in each of them. The plastic behavior of the boron steel can be well described by the presented model.

关键词： crystal plasticity integration model 22MnB5 boron steel high temperature de-formation

Control of firing activities in thermosensitive neuron by activating excitatory autapse

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Chinese Physics B 2021年第10期30卷 171-179页

作者： ying xu Jun Ma School of Mathematics and Statistics Shandong Normal UniversityJi’nan 250014China Department of Physics Lanzhou University of TechnologyLanzhou 730050China School of Science Chongqing University of Posts and TelecommunicationsChongqing 430065China

Temperature has distinct influence on the activation of ion channels and the excitability of neurons,and careful change in temperature can induce possible mode transition in the neural *** formation and development of autapse connection to neuron can enhance its self-adaption to external stimulus,and thus the firing patterns in neuron can be controlled *** autapse is activated to drive a thermosensitive neuron,which is developed from the FitzHugh-Nagumo neural circuit by incorporating a thermistor,and the dynamics in the neural activities is explored to find mode dependence on the temperature and autaptic *** is found that the firing modes can be controlled by temperature,and the neuron is wakened from resting state to periodic oscillation with the increase of ***,the intensity and the intrinsic time delay in the autapse are respectively adjusted to control the neural activities,and it is confirmed that appropriate setting for autaptic current can balance and enhance the temperature effect on the neural activities.

关键词： thermosensitive neuron autapse firing pattern bifurcation

Microbial remediation of aromatics-contaminated soil

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Frontiers of Environmental Science & Engineering 2017年第2期11卷 1-9页

作者： ying xu Ning-Yi Zhou State Key Laboratory of Microbial Metabolism & School of Life Sciences and Biotechnology Shanghai Jiao Tong University Shanghai 200240 China

Aromatics-contaminated soil is of particular environmental concern as it exhibits carcinogenic and mutagenic properties. Bioremediation, a biological approach for the removal of soil contaminants, has several advantages over traditional soil remediation methodologies including high efficiency, complete pollutant removal, low expense and limited or no secondary pollution. Bioaugmentation, defined as the introduction of specific competent strains or consortia of microorganisms, is a widely applied bioremediation technology for soil remediation. In this review, it is concluded which several successful studies of bioaugmentation of aromatics-contaminated soil by single strains or mixed consortia. In recent decades, a number of reports have been published on the metabolic machinery of aromatics degradation by microorganisms and their capacity to adapt to aromatics-contaminated environments. Thus, microorganisms are major players in site remediation. The bioremediation/bioaugmentation process relies on the immense metabolic capacities of microbes for transformation of aromatic pollutants into essentially harmless or, at least, less toxic compounds. Aromatics-contaminated soils are successfully remediated with adding not only single strains but also bacterial or fungal consortia. Furthermore several novel approaches, which microbes combined with physical, chemical or biological factors, increase remediatio.n efl~.ciency of aromatics-contaminated soil. Meanwhile, the environmental factors also have appreciable impacts on the bioaugmentation process. The biostatistics method is recommended for analysis of the effects of bioaugmentation treatments.

关键词： Aromatics-contaminated soilBacteriaBioaugmentationBioremediationFungi

An Improved Gravitational Search Algorithm for Dynamic Neural Network Identification

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International Journal of Automation and computing 2014年第4期11卷 434-440页

作者： Bao-Chang xu ying-ying Zhang Department of Automation China University of Petroleum (Beijing)

Gravitational search algorithm(GSA) is a newly developed and promising algorithm based on the law of gravity and interaction between masses. This paper proposes an improved gravitational search algorithm(IGSA) to improve the performance of the GSA, and first applies it to the field of dynamic neural network identification. The IGSA uses trial-and-error method to update the optimal agent during the whole search process. And in the late period of the search, it changes the orbit of the poor agent and searches the optimal agent s position further using the coordinate descent method. For the experimental verification of the proposed algorithm,both GSA and IGSA are testified on a suite of four well-known benchmark functions and their complexities are compared. It is shown that IGSA has much better efficiency, optimization precision, convergence rate and robustness than GSA. Thereafter, the IGSA is applied to the nonlinear autoregressive exogenous(NARX) recurrent neural network identification for a magnetic levitation *** with the system identification based on gravitational search algorithm neural network(GSANN) and other conventional methods like BPNN and GANN, the proposed algorithm shows the best performance.

关键词： Gravitational search algorithm orbital change optimization neural network system identification

CMIP5 Simulated Change in the Intensity of the Hadley and Walker Circulations from the Perspective of Velocity Potential

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Advances in Atmospheric Sciences 2016年第7期33卷 808-818页

作者： Botao ZHOU ying SHI ying xu National Climate Center China Meteorological Administration Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science & Technology

Based on the simulations of 31 global models in CMIP5, the performance of the models in simulating the Hadley and Walker circulations is evaluated. In addition, their change in intensity by the end of the 21st century （2080-2099） under the RCP4.5 and RCP8.5 scenarios, relative to 1986-2005, is analyzed from the perspective of 200 hPa velocity potential. Validation shows good performance of the individual CMIP5 models and the multi-model ensemble mean （MME） in re- producing the meridional （zonal） structure and magnitude of Hadley （Walker） circulation. The MME can also capture the observed strengthening tendency of the winter Hadley circulation and weakening tendency of the Walker circulation. Such secular trends can be simulated by 39% and 74% of the models, respectively. The MME projection indicates that the winter Hadley circulation and the Walker circulation will weaken under both scenarios by the end of the 21st century. The weak- ening amplitude is larger under RCP8.5 than RCP4.5, due to stronger external forcing. The majority of the CMIP5 models show the same projection as the MME. However, for the summer Hadley circulation, the MME shows little change under RCP4.5 and large intermodel spread is apparent. Around half of the models project an increase, and the other half project a decrease. Under the RCP8.5 scenario, the MME and 65% of the models project a weakening of the summer southern Hadley circulation.

关键词： Hadley circulation Walker circulation model evaluation CMIP5 projection velocity potential

Aorta-to-right atrium fistula,an unusual complication of endocarditis

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2009年第3期10卷 230-232页

作者： Miao-yan CHEN dan-dan ZHONG Zhi-qiang ying Department of Internal Medicine the Second Affiliated Hospital School of Medicine Zhejiang University Hangzhou 310009 China) Department of Cardiology the Second Affiliated Hospital School of Medicine Zhejiang University Hangzhou 310009 China

Infective endocarditis(IE) remains a serious disease. Aorta-to-right atrium fistula is a rare but very serious complication of IE and predicts a higher mortality. This report describes a 50-year-old man with endocarditis,vegetation,perforation of noncoronary sinus,and formation of two aorta-to-right atrium fistulas with native valves detected by transthoracic echocardiography. This disease is lethal despite developments in cardiac imaging and antibacterial therapy. Early diagnosis,aggressive antibacterial therapy,and surgical treatment may improve the prognosis.

关键词： Infective endocarditis (IE) Aorta-to-right atrium fistula Echocardiography

Hochschild (Co)homology of a Class of Nakayama Algebras

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Acta Mathematica Sinica,English Series 2008年第7期24卷 1097-1106页

作者： Yun Ge xu dan WANG Faculty of Mathematics & Computer Science Hubei University Wuhan 430062 P. R. China

Let A = kQ/I be a finite-dimensional Nakayama algebra, where Q is an Euclidean diagram An for some n with cyclic orientation, and I is an admissible ideal generated by a single monomial relation. In this note we determine explicitly all the Hochschild homology and cohomology groups of A based on a detailed description of the Bardzell complex. Moreover, the cyclic homology of A can be calculated in the case that the underlying field is of characteristic zero.

关键词： Nakayama algebra Hochschild homology cyclic homology Hochschild cohomology

Abrupt change of winter temperature over the Mongolian Plateau during 1961-2017

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Journal of Mountain Science 2023年第4期20卷 996-1009页

作者： XIA ying-ying CHUN Xi dan dan LIU Hong-yu ZHOU Hai-jun WAN Zhi-qiang Inner Mongolia Restoration Engineering Laboratory of Wetland Eco-environment System Inner Mongolia Normal UniversityHohhot010022China Key Laboratory of Mongolian Plateau’s Climate System Inner Mongolia Normal UniversityHohhot010022China College of Geographical Science Inner Mongolia Normal UniversityHohhot010022China College of Resources and Environment Baotou Teachers’CollegeBaotou014030China

Studying the abrupt change of winter temperature(ACWT)over the Mongolian Plateau(MP,including Inner Mongolia Autonomous Region and State of Mongolia)is of great significance for understanding the spatiotemporal distribution of temperature and the mechanism of global climate *** temperature data during 1961–2017was collected,and the abrupt change point was determined by the Mann–Kendall test and sliding ttest,to analyze the characteristics and causes of *** results showed that(a)The winter temperature has rapidly increased with a trend of 0.41℃/10a,which was significantly higher than that of the rest area of Chinese mainland,indicating that climate change in the MP was more sensitive to global warming.(b)The abrupt change point occurred in 1988,with temperature of-15.5℃and-14.1℃before and after abrupt change,*** ACWT in 50°N was 1–3 years later than that in 40°N,and the isotherms of different temperatures moved northward by 10–200 km,especially-16℃isotherms moved approximately 200 km northward after 1988.(c)The Arctic Oscillation(AO)and Mongolian High(MH)anomaly affects winter temperature over the *** the AO is unusually strong,the MH and East Asian winter monsoon are weak,and southerly winds prevail in most regions,which is not conducive to the cold air developing southward,leading to higher winter temperature in the ***,abnormally northerly winds prevail and temperature is ***,the abrupt change time of AO occurred in 1987 before winter *** shows that the AO indirectly causes winter temperatures to rise by influencing the MH and is also the main driving factor of ACWT.

关键词： Abrupt temperature change Spatiotemporal distribution Arctic Oscillation Winter temperature Mongolian Plateau