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Oasis System and Its Reasonable Development in Sangong River Watershed in North of the Tianshan Mountains,Xinjiang,China

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Chinese Geographical Science 2006年第3期16卷 236-242页

作者： LEI Jun luo Geping ZHANG Xiaolei LU qi Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences Urumqi 830011 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

Under the guide of system theory, taking the oasis in the Sangong River watershed as a case study, this paper analyzes the oasis structure and function from 4 aspects including oasis spatial structure, water resources structure, vegetation structure, economic structure and their corresponding functions. The results indicate that as a typical small-scale watershed, Sangong River watershed has the relatively complete mountain-basin structure, and ecological and productive function. Because of human drastic activity the utilization rate of water resources was as high as 98.7%, and the utilization of groundwater was not reasonable, which resulted in an average annual decline of 0.353m in the water table of alluvial-diluvial-fan oasis, and an average annual increase of 0.047m in the alluvial-plain. The layout of crop and shelter forest benefits to the utilization of water and land resources. The development of oasis economy is at low level, and its eco-economic function is weak.

关键词： oasis structure oasis function oasis economy Sangong River watershed

A Stabilized Crank-Nicolson Mixed Finite Element Method for Non-stationary Parabolized Navier-Stokes Equations

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Acta Mathematicae Applicatae Sinica 2017年第2期33卷 409-416页

作者： Yan-jie ZHOU Fei TENG Zhen-dong luo School of Science Beijing Technology and Business University Beijing 100048 China School of Mathematics and Physics North China Electric Power University Beijing 102206 China

In this study, a time semi-discrete Crank-Nicolson （CN） formulation with second-order time accu- racy for the non-stationary parabolized Navier-Stokes equations is firstly established. And then, a fully discrete stabilized CN mixed finite element （SCNMFE） formulation based on two local Gauss integrals and parameter- free with the second-order time accuracy is established directly from the time semi-discrete CN formulation. Thus, it could avoid the discussion for semi-discrete SCNMFE formulation with respect to spatial variables and its theoretical analysis becomes very simple. Finaly, the error estimates of SCNMFE solutions are provided.

关键词： parabolized Navier-Stokes equations stabilized Crank-Nicolson mixed finite element formulation error estimate

Application prospect of artificial intelligence in the low-carbon transition of energy system

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Science China(Technological Sciences) 2023年第7期66卷 2158-2160页

作者： luo ShiHua HU WeiHao HUANG qi CHEN Zhe School of Mechanical and Electrical Engineering University of Electronic Science and Technology of ChinaChengdu 611731China School of Information Engineering Southwest University of Science and TechnologyMianyang 621010China Department of Energy Technology Aalborg UniversityAalborg 9220Denmark

The low-carbon transition of energy systems has attracted worldwide attention for mitigating the threat of climate *** targets of controlling the global average temperature rise below 2°C and further attempts at 1.5°C are the most conspicuous international cooperation in emission reduction,which requires rapid energy transition and technological revolution [1].

关键词： transition energy artificial

Mitigating Content Caching Attack in NDN

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Computers, Materials & Continua 2018年第9期56卷 483-499页

作者： Zhiqiang Ruan Haibo luo Wenzhong Lin jie Wang Department of Computer Science Minjiang UniversityWenxian Road No.1FuzhouFujian350108China Department of Computer Science University of Massachusetts LowellOne University AvenueLowellM.A.01854USA

Content caching is a core component in Named Data Networking(NDN),where content is cached in routers and served for future ***,the adversary can launch verification attack by placing poisoned data into the network with a legitimate name and allow the routers in the delivery path to frequently identify the *** NDN employs digital signature on each piece of content,verifying all content will exhaust routers’computational resources due to the massive data in the *** this paper,we propose a selective verification scheme upon the contents that are hit in the content store and allow the contents that are not actually served to be *** also consider the redundant verification of popular content and incorporated in our design to lessen the re-accessing *** and performance results show that the proposed scheme can greatly mitigate the risk of content verification attacks and save the computational resources of relay nodes.

关键词： NDN content cache security verification attack

Mass and Volume Conservation in Phase Field Models for Binary Fluids

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Communications in Computational Physics 2013年第4期13卷 1045-1065页

作者： jie Shen Xiaofeng Yang qi Wang Department of Mathematics Purdue UniversityWest LafayetteIN 46907USA Department of Mathematics and NanoCenter at USC University of South CarolinaColumbiaSC 29028USA School of Mathematics Nankai UniversityTianjin 300071P.R.China Beijing Computational Science Research Center Beijing 100084P.R.China

The commonly used incompressible phase field models for non-reactive,binary fluids,in which the Cahn-Hilliard equation is used for the transport of phase variables(volume fractions),conserve the total volume of each phase as well as the material volume,but do not conserve the mass of the fluid mixture when densities of two components are *** this paper,we formulate the phase field theory for mixtures of two incompressible fluids,consistent with the quasi-compressible theory[28],to ensure conservation of mass and momentum for the fluid mixture in addition to conservation of volume for each fluid *** this formulation,the mass-average velocity is no longer divergence-free(solenoidal)when densities of two components in the mixture are not equal,making it a compressible model subject to an internal *** one formulation of the compressible models with internal constraints(model 2),energy dissipation can be clearly *** efficient numerical method is then devised to enforce this compressible internal *** simulations in confined geometries for both compressible and the incompressible models are carried out using spatially high order spectral methods to contrast the model *** comparisons show that(a)predictions by the two models agree qualitatively in the situation where the interfacial mixing layer is thin;and(b)predictions differ significantly in binary fluid mixtures undergoing mixing with a large mixing *** numerical study delineates the limitation of the commonly used incompressible phase field model using volume fractions and thereby cautions its predictive value in simulating well-mixed binary fluids.

关键词： Phase field model compressibility multiphase fluid flows spectral methods

Rotary bending fatigue behavior of A356 –T6 aluminum alloys by vacuum pressurizing casting

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China Foundry 2015年第5期12卷 326-332页

作者： Yong-qin Liu Wan-qi jie Zhi-ming Gao Yong-jian Zheng Hai-jun luo Wen-tao Song State Key Laboratory of Solidification Processing Northwestern Polytechnical University School of Aerospace Mechanical and Manufacturing Engineering RMIT University Simulation and Modeling of Metallurgical Processes Montanuniversitaet Leoben

Vacuum pressurizing casting technique, providing better mould filling and inter-dendritic feeding, can reduce the porosity greatly in cast aluminum alloys, and improve the fatigue properties. The rotary bending fatigue properties of A356-T6 alloys prepared by vacuum pressurizing casting were investigated. The S-N curve and limit strength 90 MPa under fatigue life of 107 cycles were obtained. The analyses on the fatigue fractography and microstructure of specimens showed that the fatigue fracture mainly occurs at the positions with casting defects in the subsurface, especially at porosities regions, which attributed to the crack propagation during the fatigue fracture process. Using the empirical crack propagation law of Pairs-Erdogon, the quantitative relationship among the initial crack size, fatigue life and applied stress was established. The fatigue life decreases with an increase in initial crack size. Two constants in the Pairs-Erdogon equation of aluminum alloy A356-T6 were calculated using the experimental data.

关键词： aluminum alloys vacuum pressurizing casting rotary bending fatigue porosity crack propagation

Continuous monitoring of diabetes with an integrated microneedle biosensing device through 3D printing

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Microsystems & Nanoengineering 2021年第5期7卷 161-172页

作者： Yiqun Liu qi Yu Xiaojin luo Li Yang Yue Cui School of Materials Science and Engineering Peking University100871 BeijingP.R.China Renal Division Peking University Institute of NephrologyPeking University First Hospital100034 BeijingP.R.China

Diabetes is a prevalent chronic metabolic disease with multiple clinical manifestations and complications,and it is among the leading causes of *** and continuous monitoring of interstitial glucose is highly desirable for diabetes *** we unprecedentedly show continuous monitoring of diabetes with an integrated microneedle biosensing *** device was manufactured with a 3D printing process,a microfabrication process,an electroplating process,and an enzyme immobilization *** device was inserted into the dermis layer of mouse skin and showed accurate sensing performance for monitoring subcutaneous glucose levels in normal or diabetic *** detection results were highly correlated with those obtained from a commercial blood glucose *** anticipate that the study could open exciting avenues for monitoring and managing diabetes,alongside fundamental studies of subcutaneous electronic devices.

关键词： needle diabetes printing

Dissipativity of Multistep Runge-Kutta Methods for Nonlinear Volterra Delay-integro-differential Equations

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Acta Mathematicae Applicatae Sinica 2012年第2期28卷 225-236页

作者： Rui qi Cheng-jian ZHANG Yu-jie ZHANG China1School of Science Naval University of Engineering Wuhan 430033 School of Mathematics and Statistics Huazhong University of Science and Technology Wuhan 430074 China School of Mathematics and Physics China University of Geosciences Wuhan 430074 China

This paper is concerned with the numerical dissipativity of multistep Runge-Kutta methods for nonlinear Volterra delay-integro-differential equations. We investigate the dissipativity properties of （k, l）- algebraically stable multistep Runge-Kutta methods with constrained grid and an uniform grid. The finite- dimensional and infinite-dimensional dissipativity results of （k, /）-algebraically stable Runge-Kutta methods are obtained.

关键词： Volterra delay-integro-differential equations multistep Runge-Kutta methods dissipativity,(k,l)-algebraically stable

Cache Pollution Prevention Mechanism Based on Deep Reinforcement Learning in NDN

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Journal of Communications and Information Networks 2021年第1期6卷 91-100页

作者： jie Zhou Jiangtao luo Junxia Wang Lianglang Deng School of Communication and Information Engineering Chongqing University of Posts and TelecommunicationsChongqing 400065China Electronic Information and Networking Research Institute Chongqing University of Posts and TelecommunicationsChongqing 400065China

As a representative architecture of contentcentric paradigms for the future Internet,named data networking(NDN)enables consumers to retrieve content duplicates from either the original server or intermediate *** node of NDN is equipped with cache that buffers but not validates the data,making it vulnerable to various *** pollution,one of the specific attacks in NDN,fraudulently alters the cached contents by excessively requesting worthless information,squeezing the space of real popular contents and thus degrading the experience of normal *** order to address the issue,this paper proposes a defense scheme based on deep reinforcement learning(DRL)against cache pollution attack,in which whether a data packet is to be cached is decided by a trained intelligent agent,that is adaptive to dynamic network states and following long term rewards,the accumulative data-requesting ***,the DRL-based scheme is evaluated and compared to two other existing *** results show that the proposed defense mechanism outperforms the others significantly,and is proved to be effective against cache pollution attacks.

关键词： named data networking cache pollution attack deep reinforcement learning