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Dynamic Mechanical Properties and Energy Dissipation Characteristics of Frozen Soil Under Passive Confined Pressure

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Acta Mechanica Solida Sinica 2021年第2期34卷 184-203页

作者： Jinxuan Jia huaiping Tang Huijian Chen Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province School of Mechanics and EngineeringSouthwest Jiaotong UniversityChengdu 610031China

Impact compression tests on frozen soil samples with different freezing temperatures and subjected to passive confined pressure were performed using a split Hopkinson pressure bar at different loading strain *** three-dimensional stress-strain curves of the frozen soil samples under the corresponding conditions were *** experimental results showed that,when the frozen soil was loaded to its elastic limit,shear failure occurred,the bearing capacity of pore ice was lost,and the thawed soil functioned as the main stress-bearing ***,the capacity of frozen soil to withstand hydrostatic pressure continued to *** dynamic mechanical properties of the frozen soil under passive confined pressure were observed to be strongly related to the loading strain rate and freezing *** the loading strain rate increased,the secant modulus,elastic modulus,and strength(including the shear strength)of the frozen soil increased,whereas its Poisson^ratio and coefficient of lateral pressure *** the freezing temperature decreased,the secant modulus,elastic modulus,and shear strength of the frozen soil increased;however,its Poisson5s ratio and coefficient of lateral pressure *** the frozen soil was subjected to impact loading under passive confined pressure,energy dissipation occurred due to plastic deformation,mesoscopic damage evolution,and ice-water phase *** shear failure occurred,the absorption energy per unit volume of frozen soil increased as the freezing temperature decreased and the loading strain rate increased.

关键词： Frozen soil Split Hopkinson pressure bar Passive confined pressure Dynamic mechanical properties Energy dissipation

The transmission of dengue virus with Aedes aegypti mosquito in a heterogeneous environment

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International Journal of Biomathematics 2021年第5期14卷 31-49页

作者： Mengyun Zhang Zhigui Lin huaiping Zhu School of Applied Mathematics Nanjing University of Finance&EconomicsNanjing 210003P.R.China School of Mathematical Science Yangzhou University Yangzhou 225002P.R.China Laboratory of Mathematical Parallel Systems(LAMPS)Department of Mathematics and Statistics York University TorontoONM3J 1P3Canada

This paper deals with dengue virus transmitted by the mosquito Aedes aegypti.A reaction-diffusion model is proposed incorporating both human and the *** population,where we divided mosquitoes into two sub-populations:the winged population and an aquatic form,with the winged mosquito population divided into the susceptible and infected *** threshold Qo depending on spatial heterogeneity is introduced for the mosquito ***,we introduce the basic reproduction number Rq for the infected classes,as well as its analytical *** and Ho are utilized to investigate the stability of the mosquito-established *** results show that the mosquitoes persist if Qo>1,while the transmission of dengue virus depends on the condition whether Ho1.

关键词： Reaction-diffusion model dengue virus Aedes aegypti mosquito basic reproduction number stability

Survey of the research on dynamic weapon-target assignment problem

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Journal of Systems Engineering and Electronics 2006年第3期17卷 559-565页

作者： Cai huaiping Liu Jingxu Chen Yingwu Wang Hao School of Information System & Management National Univ. of Defense TechnologyChangsha 410073 P. R. China

The basic concepts and models of weapon-target assignment （WTA） are introduced and the mathematical nature of the WTA models is also analyzed. A systematic survey of research on WTA problem is provided. The present research on WTA is focused on models and algorithms. In the research on models of WTA, the static WTA models are mainly studied and the dynamic WTA models are not fully studied in deed. In the research on algorithms of WTA, the intelligent algorithms are often used to solve the WTA problem. The small scale of static WTA problems has been solved very well, however, the large scale of dynamic WTA problems has not been solved effectively so far. Finally, the characteristics of dynamic WTA are analyzed and directions for the future research on dynamic WTA are discussed.

关键词： military operational research dynamic weapon-target assignment survey firepower assignment decision making combination optimization.

Analysis of a stochastic model for algal bloom with nutrient recycling

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International Journal of Biomathematics 2016年第6期9卷 59-85页

作者： Xuehui Ji Sanling Yuan huaiping Zhu School of ManagementUniversity of Shanghai for Science and Technology Shanghai 200093 P. R. China College of ScienceUniversity of Shanghai for Science and Technology Shanghai 200093 P. R. China Department of Mathematics and StatisticsYork University Toronto M3J 1P3 Canada

In this paper, the dynamics of a stochastic model for algal bloom with nutrient recy- cling is investigated. The model incorporates a white noise term in the growth equation of algae population to describe the effects of random fluctuations in the environment, and a nutrient recycling term in the nutrient equation to account for the conversion of detritus into nutrient. The existence and uniqueness of the global positive solution of the model is first proved. Then we study the long-time behavior of the model. Conditions for the extinction and persistence in the mean of the algae population are established. By using the theory of integral Markov semigroups, we show that the model has an invari- ant and asymptotically stable density. Numerical simulations illustrate our theoretical results.

关键词： Stochastic nutrient-algae model ItS's formula stochastic stability integralMarkov semigroup stationary distribution.

Digital Extraction of Altitudinal Belt Spectra in the West Kunlun Mountains Using SPOT-VGT NDVI and SRTM DEM

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Journal of Mountain Science 2010年第2期7卷 133-145页

作者： XIAO Fei LING Feng DU Yun XUE huaiping WU Shengjun Institute of Geodesy & Geophysics Chinese Academy of Sciences Wuhan 430077 China

In this paper, a digital identification method for the extraction of altitudinal belt spectra of montane natural belts is presented. Acquiring the sequential spectra of digital altitudinal belts in mountains at an acceptable temporal frequency and over a large area requires extensive time and work if traditional methods of field investigation are to be used. Such being the case, often the altitudinal belts of a whole mountain or the belts at a regional scale are represented by single points. However, single points obviously cannot accurately reflect the spatial variety of altitudinal belts. In this context, a digital method was developed to extract the spectra of altitudinal belts from remote sensing data and SRTM DEM in the *** Kunlun Mountains. By means of the 4km resolution SPOT-4 vegetation 10-day composite NDVI, the horizontal distribution of altitudinal belts were extracted through supervised classification, with a total classification accuracy of 72.23%. Then, a way of twice-scan was used to realize the automatic transition of horizontal maps to vertical belts. The classification results of remote-sensing data could thus be transformed automatically to sequential spectra of digital altitudinal belts. The upper and lower lines of the altitudinal belts were then extracted by vertical scanning of the belts. Relationships between the altitudinal belts based on the montane natural zones concerning vegetation types and the geomorphological altitudinal belts discussed. As a tentative method, were also the digital extraction method presented here is effective at digitally identifying altitudinal belts, and could be helpful in rapid information extraction over large-scale areas.

关键词： Altitudinal belt spectra Kunlun Mountains NDVI Digital extraction

Calibration and Experimental Research of a Multiple-wavelength Flame Temperature Instrumentation System

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Journal of Thermal Science 2004年第4期13卷 371-375页

作者： Zhihong Li Shi Liu huaiping Mu Fan Jiang Jianmin Guo Chinese Acad Sci Inst Engn Thermophys Beijing 100080 Peoples R China

This paper presents a study on a novel instrumentation system for the measurement of temperature distribution of combustion flames. This system operates upon the three-color principle combining advanced optical sensing and digital image processing techniques. It comprises an endoscope, a light splitter assembly, a CCD camera, a frame-grabber and associated software. This system was calibrated using a blackbody furnace as standard temperature source. The relationship between flame temperatures and grey-level of the images was established through image processing and function correlation. Experimental results obtained on a gas-fired combustion rig provide flame images and temperature distributions on three different wavelengths. Based on the flame temperature distribution the combustion conditions can be analyzed. Experimental results also reveal that this system is capable of online measurement of temperature distribution in a combustion zone. This system can potentially be applied to many areas such as power generation, metallurgy, chemical engineering. It is also a powerful tool for improving the control of combustion process. Keywords three-color method - flame monitor - temperature - imaging processing CLC number TK311

关键词： three-color method flame monitor temperature imaging processing

Dynamic modeling and optimal control of cystic echinococcosis

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Infectious Diseases of Poverty 2021年第2期10卷 25-37页

作者： Xinmiao Rong Meng Fan huaiping Zhu Yaohui zheng College of Mathematical Sciences Harbin Engineering University145 Nantong StreetHarbinHeilongjiang 150001People's Republic of China School of Mathematics and Statistics Northeast Normal University5268 Renmin StreetChangchunJilin 130024People's Republic of China CDM LAMPS and Department o f Mathematics and StatisticsYork University4700 Keele StreetTorontoON M 3 J1P3Canada Animal Health Supervision Institute of Xingan League Tiexi North RoadUlanhotInner Mongolia 137400People's Republic of China

Background:Cystic echinococcosis is one of the most severe helminth zoonosis with a drastic impact on human health and livestock *** optimal control strategy and assessing the crucial factors are essential for developing countermeasures to mitigate this ***:Two compartment models were formulated to study the dynamics of cystic echinococcosis transmission,to evaluate the effectiveness of various control measures,and to find the optimal control *** analyses were conducted by obtaining PRCCs and contour plot was used to evaluate the effect of key parameters on the basic reproduction *** on forward-backward sweep method,numerical simulations were employed to investigate effects of key factors on the transmission of cystic echinococcosis and to obtain the optimal control ***:The food resources of stray dog and invalid sheep vaccination rate,which are always neglected,were significant to the transmission and control of cystic *** simulations suggest that,the implementation of optimal control strategy can significantly reduce the *** the cost of health education and domestic dog deworming could not decrease human ***:Our study showed that only a long-term use of the optimal control measures can eliminate the ***,during the intervention,sheep vaccination and stray dogs disposing should be emphasized ahead of domestic dogs deworming to minimize the control *** reducing other wild intermediate hosts and strengthening the sheep vaccination as well as disposing the stray dogs would be most effective.

关键词： Cystic echinococcosis Dynamic modeling Optimal control Global stability Sheep vaccination

MODELING THE SCHISTOSOMIASIS ON THE ISLETS IN NANJING

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International Journal of Biomathematics 2012年第4期5卷 189-205页

作者： LONGXING QI JING-AN CUI YUAN GAO huaiping ZHU School of Mathematical Sciences Anhui University Hefei 230601 P. R. China College of Science Beijing University of Civil Engineering and Architecture Beijing 100044 P. R. China Nanjing Center for Disease Control and Prevention Nanjing 210003 P. R. China Department of Mathematics and Statistics Laboratory of Mathematical Parallel Systems and Centre for Disease Modeling York University Toronto ON Canada M3J 1P3

A compartmental model is established for schistosomiasis infection in Qianzhou and Zimuzhou, two islets in the center of Yangtzi River near Nanjing, P. R. China. The model consists of five differential equations about the susceptible and infected subpopu- lations of mammalian Rattus norvegicus and Oncomelania snails. We calculate the basic reproductive number R0 and discuss the global stability of the disease free equilibrium and the unique endemic equilibrium when it exists. The dynamics of the model can be characterized in terms of the basic reproductive number. The parameters in the model are estimated based on the data from the field study of the Nanjing Institute of Para- sitic Diseases. Our analysis shows that in a natural isolated area where schistosomiasis is endemic, killing snails is more effective than killing Rattus norvegicus for the control of schistosomiasis.

关键词： Schistosomiasis compartmental model equilibrium state stability control strategy.

Re-recognition of the Dajiuhu Wetland in Shennongjia Mountains,Central China

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湿地科学 2012年第3期10卷 278-284页

作者： XIAO Fei DU Yun XUE huaiping LING Feng BAN Xuan Institute of Geodesy and Geophysics Chinese Academy of SciencesWuhan 430077HubeiP.R.China

The Dajiuhu wetland,a famous sub-alpine wetland located in the the Shennongjia Mountains,north-subtropical region of Central China,has suffered from adverse impacts of unsustainable human practices over the past 60 *** Dajiuhu wetland reflects the development process that has been accompanied by human *** on field survey data,high resolution remote sensing image and historical records,the present paper provided a review on exploitation and restoration of the *** results showed that the Dajiuhu wetland degraded quickly from 1950 to *** that time,bog shrinkage,lake disappearance,biodiversity decline,sphagnum reduction,and vegetation succession from wetland communities to terrestrial communities in the Dajiuhu wetland,which were the main manifestations of the wetland *** activities,such as agricultural reclamation and construction of drainage works,have been the main factors resulting in ecological degradation of the wetland since *** and the short-term economic benefits had been the driving forces for wetland drainage and reclamation over the past years.

关键词： mountain wetland Dajiuhu wetland wetland degradation Shennongjia Mountains