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Effect of Magnetic Field on Forced Convection between Two Nanofluid Laminar Flows in a channel

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Chinese Journal of Mechanical Engineering 2016年第6期29卷 1235-1243页

作者： Afrasiab Raisi Ahmad Qanbary Engineering Faculty Shahrekord University

This paper provides a numerical study of forced convection between hot and cold nanofluid laminar flows that are separated by a thin membrane, in a horizontal channel. Outer surface of channels＇ walls are thermally insulated and divide into two parts; namely NMP and MP. NMP is the channel＇s wall from the entrance section to the middle section of channel that is not influenced by magnetic field. MP is the channel＇s wall from the middle section to the exit section of channel which is influenced by a uniform-strength transverse magnetic field. The governing equations for both hot and cold flows are solved together using the SIMPLE algorithm. The effects of pertinent parameters, such as Reynolds number （10 ≤ Re ≤500）, Hartman number （0 ≤Ha ≤60） and the solid volume fraction of copper nano-particles （0≤φ≤0.05）, are studied. The results are reported in terms of streamlines, isotherms, velocity and temperature profiles and local and average Nusselt number. The results of the numerical simulation indicate that the increase in Reynolds number and the solid volume fraction lead to increase in Nusselt number. Meanwhile, the results also show that the rate of heat transfer between the flows increases as the Hartmann number increases, especially at higher values of the Reynolds number.

关键词： magnetic field forced convection nanofluid membrane channel

Tauroursodeoxycholic acid(TUDCA) inhibits influenza A viral infection by disrupting viral proton channel M2

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Science Bulletin 2019年第3期64卷 180-188页

作者： Ning Li Yanxu Zhang Shuangxiu Wu Ruodan Xu Zhiqing Li Jindong Zhu Hongliang Wang Xiao Li Mingyao Tian Huijun Lu Ningyi Jin Chengyu Jiang State Key Laboratory of Medical Molecular Biology Institute of Basic Medical Sciences Chinese Academy of Medical Sciences Peking Union Medical College Tsinghua University China Academy of Chinese Medicine Sciences Interdisciplinary Nanoscience Center (iNANO) Department of Engineering Aarhus University Genetic Engineering Laboratory Institute of Military Veterinary Academy of Military Medical Sciences

Influenza is a persistent threat to human health and there is a continuing requirement for updating antiinfluenza strategies. Initiated by observations of different endoplasmic reticulum(ER) responses of host to seasonal H1N1 and highly pathogenic avian influenza(HPAI) A H5N1 infections, we identified an alternative antiviral role of tauroursodeoxycholic acid(TUDCA), a clinically available ER stress inhibitor, both in vitro and in vivo. Rather than modulating ER stress in host cells, TUDCA abolished the proton conductivity of viral M2 by disrupting its oligomeric states, which induces inefficient viral infection. We also showed that M2 penetrated cells, whose intracellular uptake depended on its proton channel activity,an effect observed in both TUDCA and M2 inhibitor amantadine. The identification and application of TUDCA as an inhibitor of M2 proton channel will expand our understanding of IAV biology and complement current anti-IAV arsenals.

关键词： Influenza TUDCA M2 proton channel Virus entry Cell-penetrating peptide Oligomerization inhibitor

Strength optimization of ultralight corrugated-channel-core sandwich panels

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Science China(Technological Sciences) 2019年第8期62卷 1467-1477页

作者： ZHAO ZhenYu LI Lang WANG Xin ZHANG QianCheng HAN Bin LU TianJian State Key Laboratory for Strength and Vibration of Mechanical Structures Xi'an Jiaotong University Xi'an 710049 China State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and Astronautics Nanjing 210016 China Nanjing Center for Multifunctional Lightweight Materials and Structures (MLMS) Nanjing University of Aeronautics and Astronautics Nanjing 210016 China School of Mechanical Engineering Xi'an Jiaotong University Xi'an 710049 China

Novel ultralight sandwich panels, which are comprised of corrugated channel cores and are faced with two identical solid sheets,subjected to generalized bending are optimally designed for minimum mass. A combined analytical and numerical(finite element) investigation is carried out. Relevant failure mechanisms such as face yielding, face buckling, core yielding and core buckling are identified, the load for each failure mode derived, and the corresponding failure mechanism maps constructed. The analytically predicted failure loads and failure modes are validated against direct finite element simulations, with good agreement achieved. The optimized corrugated channel core is compared with competing topologies for sandwich construction including corrugations, honeycombs and lattice trusses, and the superiority of the proposed structure is demonstrated. Corrugated-channel-core sandwich panels hold great potential for multifunctional applications, i.e., simultaneous load bearing and active cooling.

关键词： sandwich panel corrugated channel generalized bending optimization

Enhancement-Mode AlGaN/GaN High Electron Mobility Transistors Using a Nano-channel Array Structure

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Chinese Physics Letters 2011年第7期28卷 265-267页

作者： LIU Sheng-Hou CAI Yong GONG Ru-Min WANG Jin-Yan ZENG Chun-Hong SHI Wen-Hua FENG Zhi-Hong WANG Jing-Jing YIN Jia-Yun Cheng PWen QIN Hua ZHANG Bao-Shun Suzhou Institute of Nano-tech and Nano-bionics Chinese Academy of SciencesSuzhou 215125 Institute of Microelectronics Peking UniversityBeijing 100871 Science and Technology on ASIC Lab Hebei Semiconductor Research InstituteShijiazhuang 050051 Key Laboratory of Nanodevice and Application Suzhou Institute of Nano-tech and Nano-bionicsChinese Academy of SciencesSuzhou 215125

A nano-channel array(NCA)structure is applied to realize enhancement-mode(E-mode)AlGaN/GaN high-electron mobility transistors(HEMTs).The fabricated NCA-HEMT,consisting of 1000 channels connected in parallel with a channel width of 64 nm,shows a threshold voltage of 0.15 V and a subthreshold slope of 78 mV/dec,compared to−3.92 V and 99 mV/dec for a conventional HEMT(C-HEMT),*** the NCA-HEMT and C-HEMT show similar gate leakage current,indicating no significant degradation in gate leakage characteristics for the *** surrounding-field effect and relieved polarization contribute to the very large positive threshold voltage shift,while the work function difference makes it positive.

关键词： AlGaN/GaN polarization channel

An Efficient Approach for Mitigating Covert Storage channel Attacks in Virtual Machines by the Anti-Detection Criterion

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Journal of Computer Science & Technology 2019年第6期34卷 1351-1365页

作者： Chong Wang Nasro Min-Allah Bei Guan Yu-Qi Lin Jing-Zheng Wu Yong-Ji Wang Institute of Software Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China College of Computer Science and Information Technology Imam Abdulrahman Bin Faisal UniversityDammam 1982 Saudi Arabia Block Chain Research Center Blue HelixGrand Cayman KY1-1100Cayman Islands

Covert channels have been an effective means for leaking confidential information across security domains and numerous studies are available on typical covert channels attacks and *** covert channel threat restriction solutions are based on the threat estimation criteria of covert channels such as capacity,accuracy,and short messages which are effective in evaluating the information transmission ability of a covert(storage)***,these criteria cannot comprehensively reflect the key factors in the communication process such as shared resources and synchronization and therefore are unable to evaluate covertness and complexity of increasingly upgraded covert storage *** a solution,the anti-detection criterion was introduced to eliminate these limitations of cover *** effective,most threat restriction techniques inevitably incur high performance overhead and hence become *** this work,we avoid such overheads and present a restriction algorithm based on the anti-detection criterion to restrict threats that are associated with covert storage channels in virtual machines while maintaining the resource efficiency of the *** evaluation shows that our proposed solution is able to counter covert storage channel attacks in an effective *** with Pump,a well-known traditional restriction algorithm used in practical systems,our solution significantly reduces the system overhead.

关键词： covert storage channel information security covert channel threat evaluation security and privacy protection

Effects of vegetation patch density on flow velocity characteristics in an open channel

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Journal of Hydrodynamics 2019年第5期31卷 1052-1059页

作者： Wen-qi Li Dan Wang Jun-li Jiao Ke-jun Yang State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan UniversityChengdu 610065China

The aquatic plants are often found in natural rivers,and they affect the channel flow structure *** study the effects of the vegetation density a(the frontal area per volume)on the flow velocity characteristics,rigid bamboo circular cylinders are chosen as the model emergent *** the experiments,the density of the vegetation takes various values while all other flow parameters are kept constant.A 3-D acoustic Doppler velocimeter(ADV)is used to measure the local flow velocities for different vegetation *** results show that the existence of the vegetation patch leads to an increase of the depth-averaged velocity on the right and left sides behind the vegetation patch,and it increases monotonically with the vegetation *** different vegetation densities,the lateral distribution of the stream-wise velocity behind the vegetation patch follows approximately an S-shaped profile when a≤60 m-1,and a logarithmic profile if a>60 *** vertical distribution of the stream-wise velocity along the channel varies with the vegetation density and also follows an S-shaped distribution in a certain range,with the locations and the ranges being affected by the vegetation density.

关键词： Vegetation density stream-wise velocity depth-averaged velocity lateral distribution longitudinal distribution open channel

The best hydraulic section of horizontal-bottomed parabolic channel section

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Journal of Hydrodynamics 2017年第2期29卷 305-313页

作者：韩延成高学平徐征和 School of Resources and Environment University of Jinan State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin University

The best hydraulic channel section makes the maximum flow capacity for the same flow cross-area, and the minimum cross-area and wetted perimeter for the same discharge. The construction cost can be reduced nearly to the minimum at the same time The horizontal bottom parabolic section （HBP section） is a composite section. It is important for design to find the best combination form of the horizontal bottom and the parabolic sides. This paper studies the best hydraulic section and its hydraulic characteristics. The explicit formulae are proposed to determine the dimensions and the best combination form of the horizontal bottom and the parabolic sides. These explicit formulae and the parameters make it easy to design the channel. It is shown that the ratios of the surface width to the depth and the bottom width to the depth are constant for the best hydraulic section. The comparisons with the classic parabolic, rectangular, trapezoid, triangular, semi-cubic and horizontal-bottomed semi-cubic sections show that the HBP section has the largest flow capacity and the shortest wetted perimeter for the same flow area, and has the smallest flow area for the same discharge. It is indicated that the parabolic side parts of the best hydraulic HBP section are different from those of the classic section. The results of the best hydraulic section of the classic parabolic channel cannot be applied directly to the HBC section.

关键词： channel parabolic shape horizontal-bottomed best hydraulic section

Focusing characteristics of the relativistic electron beam transmitting in ion channel

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Plasma Science and Technology 2020年第8期22卷 34-40页

作者： Yuxi XIA Shengpeng YANG Shaoyong CHEN Changjian TANG College of Physics Sichuan UniversityChengdu 610064People's Republic of China

Based on the beam-plasma system model established in this paper,the trajectory of the electron beam in the ion channel is studied quantitatively through the envelope *** different initial system parameters,the focusing transmission conditions of the beam in the ion channel are ***,a series of particle-in-cell simulations are performed,which generally versifies the theoretical results and shows some further details of the focusing behavior of the *** is found that the deceleration of some electrons around the focusing point or the beam-plasma interaction at the ion channel boundary will result in the generation of the residual electrons,which forms the electron return current that leads to the new instabilities influencing the focusing characteristics of the beam.

关键词： plasma ion channel beam-plasma system electron beam envelop

Characterization of the flowability dynamics of granular material flowing down a narrow channel

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Particuology 2020年第6期18卷 72-82页

作者： Ningsheng Wang Haifeng Lu Jianliang Xu Xiaolei Guo Haifeng Liu Key Laboratory of Coal Gasification and Energy Chemical Engineering of Ministry of Education East China University of Science and TechnologyP.O.Box 272Shanghai 200237China Shanghai Engineering Research Center of Coal Gasification East China University of Science and TechnologyP.O.Box 272Shanghai 200237China Ningbo Ruiling Institute for Energy and Environment Solutions Ningbo 315500China

The flowability of granular material is commonly determined from shear cell tests,but in the real world,the granular flow is quite different in many *** this paper,the flowabilities in a narrow channel of five different granular materials were *** flow parameters of the granular flows were determined to classify the flowabil让*** flow surface velocities and flow heights and thicknesses were measured,and it was found that the mean shear rates in the linear portions of the velocity profiles in crease with both flow rates and incli nation.A universal parameter,the ratio of the sine of the inclin ation to the shear rate in the linear part of the velocity profile,is proposed as a *** constant is independent of particle *** addition,a flowability parameter,the ratio of the mean shear rate to the cosine of the inclination,is proposed to characterize the friction between the particles in the flowing granular material.

关键词： Dynamic characterization Granular flow Velocity profile Flowability channel