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A Comprehensive Experimental Study on Immiscible Displacements in Porous Media:Effects of Capillary Forces,Viscous Forces,Wettability and Pore Geometries

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Journal of Thermal science 2021年第6期30卷 2137-2149页

作者： HUANG Chao DAI Xiaoye SHI Changxing SHI Lin Department of Energy and Power Engineering Tsinghua UniversityBeijing 100084China Key Laboratory of Thermal science and Power Engineering of Ministry of Education of China Beijing 100084China Key Laboratory for C02 Utilization and Reduction Technology of Beijing Beijing 100084China Department of Mechanical and Industrial Engineering University of Illinois at ChicagoChicago 60607United States

Immiscible displacements in porous media are fundamentally significant for many natural processes and industrial *** extensive work has been done in this field,some limitations still exist due to the difficulty to cover the large number of influencing *** this paper,we present a systematic study involving the coupled influence of capillary forces,viscous forces,wetting properties and pore *** microfluidic experiments with high resolutions,both residual fluid distributions and dynamical invasion processes were clearly captured and quantitatively characterized.A void-filling behavior was identified for drainage as the capillary number Ca *** anomalous void-leaving behavior was found for the case of imbibition with an unfavorable viscosity ratio M,representing many ribbon-like regions invaded at intermediate Ca turned to be not accessible at high Ca.A pore geometry with a large typical pore-throat ratio seemed to enhance the void-leaving *** the dynamical invasion processes,an intermittency behavior was captured in the form of a fluctuation of the increasing rate of the invading saturation with *** intermittency dynamics were most evident for drainage with an unfavorable M.A pore geometry with high porosity acted to suppress the intermittency *** experimental results sketched out a full view of immiscible displacements in porous media under different conditions,and provided a complete dataset which could be used to test the rapid developing pore-scale models.

关键词： immiscible displacements porous media microfluidic experiments fluid distributions intermittency dynamics

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DEVELOPMENT OF STEP-POOL SEQUENCE AND ITS EFFECTS IN RESISTANCE AND STREAM BED STABILITY

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International Journal of Sediment research 2004年第3期19卷 161-171页

作者： Zhao-Yin WANG, Jiang XU and Changzhi LI Professor, Dept. of Hydraulic Engineering, Tsinghua University, Beijing & Chairman of Advisory Council, International research and Training Center on Erosion and Sedimentation, 100084, China, Email: zywang@***.M. Phil., Dr. & Post Doctorate research fellow, Dept. of Hydraulic Engineering, Tsinghua University, Beijing, 100084, China Dept. of Hydraulic Engineering Tsinghua University Beijing & Chairman of Advisory Council International Research and Training Center on Erosion and Sedimentation 100084 China Dr. & Post Doctorate research fellow Dept. of Hydraulic Engineering Tsinghua University Beijing 100084 China

Experiments were conducted and field investigations were performed to study the development of step-pool sequence and its effects on resistance to the flow and stream bed stability. Step-pool sequence develops in incised channels as a result of streambed erosion, which is compared with sand dunes and armor layer of the role in resistance and streambed protection. The tight interlocking of particles in steps gives them an inherent stability which only extreme floods are likely to disturb. That stability suggests that step-pools are a valid equilibrium form, especially when coupled with their apparent regularity form and their role in satisfying the extreme condition of resistance maximization. The development degree of step-pools, SP, is proportional to the streambed slope. If the incoming sediment load is equal to or more than the sediment-carrying capacity of the flow, there is no bed erosion and thence there are no step-pools. If the flow depth increases and is over the step-height the resistance caus

关键词： Step-pool Streambed stability Erosion Resistance Rate of energy dissipation Manning’s roughness n

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Super and Weak Poincare Inequalities for Hypoelliptic Operators

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Acta Mathematicae Applicatae Sinica 2009年第4期25卷 617-630页

作者： Feng-yu Wangt School of Mathematical sciences and Lab. Math. Com. Sys. Beijing Normal University Beijing 100875 China Department of Mathematics Swansea University Singleton Park SA2 8PP Swansea UK

Sufficient conditions are presented for super/weak Poincare inequalities to hold for a class of hypoelliptic operators on noncompact manifolds. As applications, the essential spectrum and the convergence rate of the associated Markov semigroup are described for Gruschin type operators on R2 and Kohn-Laplacian type operators on the Heisenberg group.

关键词： Hypoelliptic operator super Poincare inequality essential spectrum weak Poincar~ inequality

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Spectral Gap and Logarithmic Sobolev Constant for Continuous Spin Systems

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Acta Mathematica Sinica,English Series 2008年第5期24卷 705-736页

作者： Mu Fa CHEN School of Mathematical sciences Beijing Normal University Beijing 100875 P. R. China

The aim of this paper is to study the spectral gap and the logarithmic Sobolev constant for continuous spin systems. A simple but general result for estimating the spectral gap＇of finite dimensional systems is given by Theorem 1.1, in terms of the spectral gap for one-dimensional marginals. The study of this topic provides us a chance, and it is indeed another aim of the paper, to justify the power of the results obtained previously. The exact order in dimension one （Proposition 1.4）, and then the precise leading order and the explicit positive regions of the spectral gap and the logarithmic Sobolev constant for two typical infinite-dimensional models are presented （Theorems 6.2 and 6.3）. Since we are interested in explicit estimates, the computations become quite involved. A long section （Section 4） is devoted to the study of the spectral gap in dimension one.

关键词： spectral gap logarithmic Sobolev constant spin system principal eigenvalue

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Association of miRNA-122-binding site polymorphism at the interleukin-1 a gene and its interaction with hepatitis B virus mutations with hepatocellular carcinoma risk

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Frontiers of Medicine 2014年第2期8卷 217-226页

作者： Yan Du Xue Han Rui Pu Jiaxin Xie Yuwei Zhang Guangwen Cao Department of Epidemiology Second Military Medical University Shanghai 200433 China Division of Chronic Diseases Center for Disease Control and Prevention of Yangpu District Shanghai 200090 China

This study was designed to investigate the contribution of miRNA-122-binding site polymorphism at the IL-1A gene and its multiplicative interactions with hepatitis B virus （HBV） mutations in the risk of hepatocellular carcinoma （HCC）. A total of 1021 healthy controls, 302 HBV surface antigen （HBsAg） seroclearance subjects, and 2011 HBsAg-positive subjects （including 1021 HCC patients） were enrolled in this study. Quantitative PCR was used to genotype rs3783553. HBV mutations were determined by direct sequencing. Multivariate logistic regression analyses were performed to test the associations of rs3783553, mutations, and their interactions with the risk of HCC. No significant association was found between rs3783553 and the risk of HCC among healthy controls, HBsAg seroclearance subjects, HBsAg-positive subjects without HCC, and all controls. Additionally, rs3783553 was not significantly associated with chronic HBV infection, liver cirrhosis, HBV e antigen seroconversion, abnormal alanine aminotransferase, and high viral load （〉 10^4 copies/ml）. However, the TTCA insertion allele of rs3783553 was significantly associated with an increased frequency of HBV C7A mutation compared with homozygous TTCA deletion carriers [（del/ins ＋ ins/ins） vs. del/del, adjusted odds ratio （OR）= 1.48, 95% confidence interval （CI）= 1.09-2.02, P = 0.013]. Multiplicative interaction of rs3783553 with HBV preS deletion significantly reduced the risk of HCC in males, with an adjusted OR of 0.64 （95% CI = 0.42-0.98; P = 0.041） after age and HBV genotype were adjusted. Although rs3783553 did not significantly affect genetic susceptibility to HBV-related HCC, its variant allele may predispose the host to selecting HBV C7A mutation during evolution and significantly reduce the risk of HCC caused by HBV preS deletion. This study provides an insight into the complex host-virus interaction in HBV-induced hepatocarcinogenesis and is helpful in determining HBsAg-positive subjects who are likely to de

关键词： miRNA-122-binding site IL-1A rs3783553 hepatitis B virus (HBV) mutations hepatocellular carcinoma (HCC) interaction

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Divergent Projection Patterns Revealed by Reconstruction of Individual Neurons in Orbitofrontal Cortex

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Neuroscience Bulletin 2021年第4期37卷 461-477页

作者： Junjun Wang Pei Sun Xiaohua Lv Sen Jin Anan Li Jianxia Kuang Ning Li Yadong Gang Rui Guo Shaoqun Zeng Fuqiang Xu Yu-Hui Zhang Britton Chance Center for Biomedical Photonics Wuhan National Laboratory for Optoelectronics-Huazhong University of Science and TechnologyWuhan430074China MoE Key Laboratory for Biomedical Photonics School of Engineering SciencesHuazhong University of Science and TechnologyWuhan430074China Centre for Brain science State Key Laboratory of Magnetic Resonance and Atomic Molecular PhysicsKey Laboratory of Magnetic Resonance in Biological SystemsWuhan Institute of Physics and MathematicsCAS Centre for Excellence in Brain Science and Intelligence TechnologyChinese Academy of SciencesWuhan430071China

The orbitofrontal cortex(OFC)is involved in diverse brain functions via its extensive projections to multiple target *** is a growing understanding of the overall outputs of the OFC at the population level,but reports of the projection patterns of individual OFC neurons across different cortical layers remain ***,by combining neuronal sparse and bright labeling with a whole-brain florescence imaging system(fMOST),we obtained an uninterrupted three-dimensional whole-brain dataset and achieved the full morphological reconstruction of 25 OFC pyramidal *** compared the wholebrain projection targets of these individual OFC neurons in different cortical layers as well as in the same cortical *** found cortical layer-dependent projections characterized by divergent patterns for information *** study not only provides a structural basis for understanding the principles of laminar organizations in the OFC,but also provides clues for future functional and behavioral studies on OFC pyramidal neurons.

关键词： Orbitofrontal cortex Whole-brain imaging Morphological reconstruction Output Projection pattern

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Distributed event-triggered adaptive control for second-order nonlinear uncertain multi-agent systems

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Chinese Journal of Aeronautics 2021年第10期34卷 237-247页

作者： Ming XIAO Zhitao LIU Hongye SU The State Key Laboratory of Industrial Control Technology Institute of Cyber-Systems and ControlZhejiang UniversityHangzhou 310027China

In this paper,the event-triggered consensus control problem for nonlinear uncertain multi-agent systems subject to unknown parameters and external disturbances is *** dynamics of subsystems are second-order with similar structures,and the nodes are connected by undirected *** event-triggered mechanisms are not only utilized in the transmission of information from the controllers to the actuators,and from the sensors to the controllers within each agent,but also in the communication between *** on the adaptive backstepping method,extra estimators are introduced to handle the unknown parameters,and the measurement errors that occur during the event-triggered communication are well handled by designing compensating terms for the control *** presented distributed event-triggered adaptive control laws can guarantee the boundness of the consensus tracking errors and the Zeno behavior is ***,the update frequency of the controllers and the load of communication burden are vastly *** obtained control protocol is further applied to a multi-input multi-output second-order nonlinear multi-agent system,and the simulation results show the effectiveness and advantages of our proposed method.

关键词： Adaptive distributed control structure Event-triggered control Multi-agent systems Second-order nonlinear models

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Material Compatibility of Hexamethyldisiloxane as Organic Rankine Cycle Working Fluids at High Temperatures

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Journal of Thermal science 2020年第1期29卷 25-31页

作者： DAI Xiaoye SHI Lin QIAN Weizhong Department of Chemical Engineering Tsinghua UniversityBeijing 100084China Department of Energy and Power Engineering Tsinghua UniversityBeijing 100084China

The organic Rankine cycle(ORC)is a promising technology for industrial waste heat recovery and renewable energy *** temperature ORCs have attracted particular interest because of their high thermal efficiencies and *** material compatibility of working fluid is a significant limitation for the working fluid selection and system design for high temperature *** work presents a method for studying the material compatibility of ORC working fluids based on the calculated conditions of the ORCs and matching of components,temperatures,and ***(MM)was chosen as the test *** experimental results show that 304 stainless steel has better compatibility with MM than copper as the material of *** rubber is not a suitable sealing material for high temperature ORCs with MM as the working fluids because of the bad *** oil has better compatibility with MM than polyol ester(POE)lubricant as the lubricant for the fluid pump.

关键词： organic Rankine cycle(ORC) material compatibility high temperatures hexamethyldisiloxane(MM)

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Review of the Working Fluid Thermal Stability for Organic Rankine Cycles

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Journal of Thermal science 2019年第4期28卷 597-607页

作者： DAI Xiaoye SHI Lin QIAN Weizhong Department of Chemical Engineering Tsinghua UniversityBeijing 100084China Department of Energy and Power Engineering Tsinghua UniversityBeijing 100084China

The organic Rankine cycle(ORC)is an efficient power generation technology and has been widely used for renewable energy utilization and industrial waste heat *** stability is a significant property of ORC working fluids and is the primary limitation for working fluid selection and system *** paper presents a review of the working fluid thermal stability for ORCs,including an analysis of the main theoretical method for thermal stability,a summary of the main experimental method for thermal stability,a summary of the decomposition experimental results for working fluids,and a discussion of the decomposition influence on ORC *** research trends of thermal stability are also discussed in this paper.

关键词： organic Rankine cycle(ORC) working fluid thermal stability

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Challenges of Processing and Analyzing Big Data in Mesoscopic Whole-brain Imaging

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Genomics, Proteomics & Bioinformatics 2019年第4期17卷 337-343页

作者： Anan Li Yue Guan Hui Gong Qingming Luo Britton Chance Center for Biomedical Photonics Wuhan National Laboratory for OptoelectronicsHuazhong University of Science and TechnologyWuhan 430074China MOE Key Laboratory for Biomedical Photonics School of Engineering SciencesHuazhong University of Science and TechnologyWuhan 430074China HUST-Suzhou Institute for Brainsmatics JITRI Institute for BrainsmaticsSuzhou 215125China

The brain is recognized as the most complex organ on *** complex neuronal network in the human brain consists of approximately 86 billion neurons and more than one hundred trillion connections[1].Even the mouse brain,which is commonly used as a model in neuroscience studies,contains more than 71 million *** the great efforts made by the neuroscientists,our knowledge about the brain is still limited and studies on small model animals have only provided preliminary results[2–4].To improve the situation,brainsmatics studies try to accelerate neuroscience research by providing a standard whole-brain spatial coordinate system and standardized labeling tools,imaging the brain,as well as discovering new neuronal cell types,neuronal circuits,and brain vascular structures.

关键词： Whole spite coordinate

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