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Investigation on the vortical structures by the Liutex method in turbulent channels at Re_(τ)=180 with scalloped and triangular riblet control

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Journal of Hydrodynamics 2024年第1期36卷 35-52页

作者： Zhang-dan yu Shang Jiang hai-dong yu Bi-yu Pang Xin dong Yi-qian Wang School of Mathematical Sciences Soochow UniversitySuzhou215006China Beijing Institute of Astronautical System Engineering Beijing100076China

Riblets are a series of small protrusions formed along the flow direction,which have been extensively studied as a passive turbulent drag reduction *** and numerical simulations have shown that well-designed riblets can significantly reduce drag in turbulent flows,making them highly promising and valuable for various *** this study,we focus on a scalloped riblet,which is designed by smoothly connecting two third-order polynomials,and thus the sharpness of the tip and the curvature of the valley can be well *** conduct direct numerical simulations of turbulent channel with smooth plate,scalloped riblet-mounted and triangular riblet-mounted *** in wall units of W^(+)=20 and height-width ratio ofγ=0.5 are selected for both riblet *** with the smooth plate case,the scalloped riblet case achieves an 8.68%drag reduction,while the triangular riblet case achieves a 4.79%drag *** obtained drag reduction rate of the triangular riblet is consistent with previous experiments and simulations,and the results indicate that the scalloped riblet is more effective in reducing drag and deserves further *** compare turbulent statistics of the scalloped riblet case with those of the triangular riblet *** mean velocity profiles of riblets are similar,but both the Reynolds shear stress and second-order statistics of velocity fluctuations and Liutex are significantly reduced in the scalloped riblets controlled turbulent channel,indicating that the scalloped riblet can more effectively suppress the spanwise and wall-normal turbulent intensity near the *** also compare the pre-multiplied spectra of streamwise velocity and streamwise Liutex component for the three cases to investigate the energy distribution and characteristics of Liutex *** Liutex vortex identification method is also utilized to analyze the instantaneous flow field,which provides insights into the flow field and could be bene

关键词： Liutex vector riblet drag reduction tip sharpness turbulent channel scalloped

Liutex-based vortex control with implications for cavitation suppression

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Journal of Hydrodynamics 2021年第1期33卷 74-85页

作者： Yi-qian Wang hai-dong yu Wei-wen Zhao De-cheng Wan School of Mathematical Science Soochow UniversitySuzhou 215006China School of Aerospace Engineering Tsinghua UniversityBeijing 100084China Computational Marine Hydrodynamics Lab(CMHL) State Key Laboratory of Ocean EngineeringSchool of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Viewed as sinews and muscles of fluid motion,coherent vortical structures with their interactions are key to understanding the flow *** upon this observation,we explore the possibility of efficient flow control by directly manipulating vortices numerically inside the flow field based on the vortex definition and identification system of *** objective is twofold:(1)to study the vortex dynamics,for example,by observing the response of the flow to strengthening or weakening of certain vortices,and(2)to obtain efficient vortex-based control strategies which might lead us to practical *** the present numerical study,the manipulating of vortices is achieved by introducing additional source(force)terms to the Navier-Stokes equations,which hereafter will be collectively called Liutex force field *** including controlling the rotation strength and centripetal force of particular vortices are detailed in a flow past a cylinder with different control purposes at Reynolds number of *** examples are provided with a cavitating flow around two-dimensional Clark-Y hydrofoil,with particular interests on cavitation *** is illustrated particular vortex with cavitation encircled could be effectively suppressed.

关键词： Vortex dynamics Liutex vector flow control cavitation Introduction

Recent Development of Gas Sensing Platforms Based on 2D Atomic Crystals

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Research 2021年第1期2021卷 1445-1482页

作者： Jiacheng Cao Qian Chen Xiaoshan Wang Qiang Zhang hai-dong yu Xiao Huang Wei Huang Frontiers Science Center for Flexible Electronics Xi’an Institute of Flexible Electronics(IFE)and Xi’an Institute of Biomedical Materials&EngineeringNorthwestern Polytechnical University127 West Youyi RoadXi’an 710072China Key Laboratory of Flexible Electronics(KLOFE)&Institute of Advanced Materials(IAM) Nanjing Tech University(NanjingTech)30 South Puzhu RoadNanjing 211800China

Sensors,capable of detecting trace amounts of gas molecules or volatile organic compounds(VOCs),are in great demand for environmental monitoring,food safety,health diagnostics,and national *** the era of the Internet of Things(IoT)and big data,the requirements on gas sensors,in addition to sensitivity and selectivity,have been increasingly placed on sensor simplicity,room temperature operation,ease for integration,and *** key to meet these requirements is the development of high-performance gas sensing ***-dimensional(2D)atomic crystals,emerged after graphene,have demonstrated a number of attractive properties that are beneficial to gas sensing,such as the versatile and tunable electronic/optoelectronic properties of metal chalcogenides(MCs),the rich surface chemistry and good conductivity of MXenes,and the anisotropic structural and electronic properties of black phosphorus(BP).While most gas sensors based on 2D atomic crystals have been incorporated in the setup of a chemiresistor,field-effect transistor(FET),quartz crystal microbalance(QCM),or optical fiber,their working principles that involve gas adsorption,charge transfer,surface reaction,mass loading,and/or change of the refractive index vary from material to *** the gas-solid interaction and the subsequent signal transduction pathways is essential not only for improving the performance of existing sensing materials but also for searching new and advanced *** this review,we aim to provide an overview of the recent development of gas sensors based on various 2D atomic crystals from both the experimental and theoretical *** will particularly focus on the sensing mechanisms and working principles of the related sensors,as well as approaches to enhance their sensing ***,we summarize the whole article and provide future perspectives for the development of gas sensors with 2D materials.

关键词： Crystal simplicity attractive

Online Condition Monitoring of Gripper Cylinder in TBM Based on EMD Method

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Chinese Journal of Mechanical Engineering 2017年第6期30卷 1325-1337页

作者： Lin Li Jian-Feng Tao hai-dong yu Yi-Xiang Huang Cheng-Liang Liu State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong University Shanghai 200240 China Shanghai Key Laboratory of Digital Manufacture for Thin-walled Structures Shanghai 200240 China

The gripper cylinder that provides braced force for Tunnel Boring Machine （TBM） might fail due to severe vibration when the TBM excavates in the tunnel. Early fault diagnosis of the gripper cylinder is important for the safety and efficiency of the whole tunneling project. In this paper, an online condition monitoring system based on the Empirical Mode Decomposition （EMD） method is estab- lished for fault diagnosis of the gripper cylinder while TBM is working. Firstly, the lumped mass parameter model of the gripper cylinder is established considering the influence of the variable stiffness at the rock interface, the equivalent stiffness of the oil, the seals, and the copper guide sleeve. The dynamic performance of the gripper cylinder is investigated to provide basis for its health condition evaluation. Then, the EMD method is applied to identify the characteristic frequencies of the gripper cylinder for fault diagnosis and a field test is used to verify the accuracy of the EMD method for detection of the characteristic frequencies. Furthermore, the contact stiff- ness at the interface between the barrel and the rod is calculated with Hertz theory and the relationship between the natural frequency and the stiffness varying with the health condition of the cylinder is simulated based on the dynamic model. The simulation shows that the character- istic frequencies decrease with the increasing clearance between the barrel and the rod, thus the defects could be indicated by monitoring the natural frequency. Finally, a health condition management system of the gripper cylin- der based on the vibration signal and the EMD method is established, which could ensure the safety of TBM.

关键词： Fault diagnosis - Empirical modedecomposition (EMD) Condition Monitoring - Grippercylinder TBM

Mechanism of trifluoromethylation reactions with well-defined NHC copper trifluoromethyl complexes and iodobenzene:A computational exploration

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Chinese Chemical Letters 2015年第5期26卷 564-566页

作者： dong-hai yu Jing-Na Shao Rong-Xing He Ming Li School of Chemistry and Chemical Engineering Southwest University

Computational calculation was performed to investigate the mechanism of trifluoromethylation reactions of iodobenzene with well-defined N-heterocyclic carbene （NHC）-supported Cu~ trifiuor- omethyl complexes. Four proposed reaction pathways, namely cr-bond metathesis （BM）, concerted oxidative addition-reductive elimination （OARE）, iodine atom transfer （IAT） and single-electron transfer （SET）, have been computed by density functional theory （DFT）. The result indicated that the concerted OARE mechanism is favored among the four reaction pathways, suggesting the trifluoromethylation may occur via concerted OARE mechanism involving Ar-X oxidative addition to the Cu（1） center as the rate determining step.

关键词： Trifluoromethylation Mechanism Density functional theory N-Heterocyclic carhene Trifluoromethyl copper complex

Flexible organic electrochemical transistors for chemical and biological sensing

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Nano Research 2022年第3期15卷 2433-2464页

作者： Li Wang Xiaoping yue Qizeng Sun Linrong Zhang Guozhang Ren Gang Lu hai-dong yu Wei Huang Key Laboratory of Flexible Electronics(KLOFE)and Institute of Advanced Materials(IAM) Nanjing Tech University(NanjingTech)30 South Puzhu RoadNanjing 211816China Frontiers Science Center for Flexible Electronics Xi'an Institute of Flexible Electronics(IFE)and Xi'an Institute of Biomedical Materials&EngineeringNorthwestern Polytechnical University127 West Youyi RoadXi'an 710072China

Chemical and biological sensing play important roles in healthcare,environmental science,food-safety tests,and medical *** organic electrochemical transistors(OECTs)have shown great promise in the field of chemical and biological sensing,owing to their superior sensitivity,high biocompatibility,low cost,and light ***,we summarize recent progress in the fabrication of flexible OECTs and their applications in chemical and biological *** start with a brief introduction to the working principle,configuration,and sensing mechanism of the flexible OECT-based ***,we focus on the fabrication of flexible OECT-based sensors,including material selection and structural engineering of the components in OECTs:the substrate,electrodes,electrolyte,and ***,the gate modification is discussed ***,the applications of OECT-based sensors in chemical and biological sensing are reviewed in ***,the array-based and integrated OECT sensors are also ***,we present the conclusions and remaining challenges in the field of flexible OECT-based *** timely review will deepen the understanding of the flexible OECT-based sensors and promote the further development of the fast-growing field of flexible sensing.

关键词： flexible electronics organic electrochemical transistors soft material structural design chemical and biological sensing

Carbonylation and Loss-of-Function Analyses of SBPase Reveal Its Metabolic Interface Role in Oxidative Stress, Carbon Assimilation, and Multiple Aspects of Growth and Development in Arabidopsis

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Molecular Plant 2012年第5期5卷 1082-1099页

作者： Xun-Liang Liu hai-dong yu yuan Guan Ji-Kai Li Fang-Qing Guo The National Key Laboratory of Plant Molecular Genetics and National Center for Plant Gene Research (Shanghai) Institute of Plant Physiology and EcologyShanghai Institutes for Biological Sciences Chinese Academy of Sciences 300 Fenglin Road Shanghai 200032 China

Sedoheptulose-l,7-bisphosphatase （SBPase） is a Calvin cycle enzyme and functions in photosynthetic carbon fixation. We found that SBPase was rapidly carbonylated in response to methyl viologen （MV） treatments in detached leaves of Arabidopsis plants. In vitro activity analysis of the purified recombinant SBPase showed that SBPase was car- bonylated by hydroxyl radicals, which led to enzyme inactivation in an H202 dose-dependent manner. To determine the conformity with carbonylation-caused loss in enzymatic activity in response to stresses, we isolated a loss-of-function mutant sbp, which is deficient in SBPase-dependent carbon assimilation and starch biosynthesis, sbp mutant exhibited a severe growth retardation phenotype, especially for the developmental defects in leaves and flowers where SBPASE is highly expressed. The mutation of SBPASE caused growth retardation mainly through inhibition of cell division and ex- pansion, which can be partially rescued by exogenous application of sucrose. Our findings demonstrate that ROS-induced oxidative damage to SBPase affects growth, development, and chloroplast biogenesis in Arabidopsis through inhibiting carbon assimilation efficiency. The data presented here provide a case study that such inactivation of SBPase caused by carbonyl modification may be a kind of adaptation for plants to restrict the operation of the reductive pentose phosphate pathway under stress conditions.

关键词： SBPase carbonyl modification oxidative stress carbon assimilation starch accumulation growth inhibition.

New freshwater plesiosaurian materials from the Middle Jurassic Xintiangou Formation of the Sichuan Basin, southwestern China

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Journal of Palaeogeography 2020年第4期9卷 469-479页

作者： Feng Zhang hai-dong yu Can Xiong Zhao-Ying Wei Guang-Zhao Peng Xue-Fang Wei Chongqing Laboratory of Geoheritage Protection and Research No.208 Hydrogeological and Engineering Geological TeamChongqing Bureau of Geological and Mineral Resource Exploration and DevelopmentChongqing 400700China Zigong Dinosaur Museum Zigong 643000Sichuan ProvinceChina Institute of Geology Chinese Academy of Geological SciencesBeijing 100037China China University of Geosciences(Beijing) Beijing 100083China Cores and Samples Centre of Natural Resources Chinese Geological SurveyBeijing 100192China

Sichuan Basin is very famous for the Mesozoic reptiles, especially the Jurassic dinosaurs. Here, we report some isolated plesiosaurian teeth and vertebrae newly excavated from the Middle Jurassic Xintiangou Formation in yunyang county, Chongqing City, the northeastern region of the Sichuan Basin, southwestern China. The specimens are referred to Pliosauroidea based on the combination of the following features: the circular cross-section of the tooth crown, apicobasal ridges fully covering the enamel surface and reaching to the apex, the short and amphicoelous centrum, the centrum shorter than wide or tall, and the absence of a keel on the lateral surface of the cervical centrum. With the fragmentary nature, it is undetermined whether the yunyang specimens belong to a known taxon or represent a new species of Plesiosauria. These plesiosaurian specimens further demonstrate that the freshwater plesiosaurians are common in the Jurassic deposits of the Sichuan Basin. For a comprehensive knowledge of the plesiosaurians of the basin in origin, distribution and diversity, to discover new and more complete specimens is necessarily the first priority.

关键词： Plesiosauria Pliosauroidea Middle Jurassic Xintiangou Formation Sichuan Basin

Flexible, transparent nanocellulose paper-based perovskite solar cells

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npj Flexible Electronics 2019年第1期3卷 42-49页

作者： Lei Gao Lingfeng Chao Meihui Hou Jin Liang Yonghua Chen hai-dong yu Wei Huang Institute of Advanced Materials(IAM)&Key Laboratory of Flexible Electronics(KLOFE) Jiangsu National Synergetic Innovation Center for Advanced Materials(SICAM)Nanjing Tech University(NanjingTech)30 South Puzhu Road211816 NanjingChina Shanxi Institute of Flexible Electronics(SIFE) Northwestern Polytechnical University127 West Youyi Road710072 Xi’anChina

Recently perovskite solar cells(PSCs),as photoelectric conversion devices,exhibit excellent power conversion efficiency(PCE)and low-processing cost,and have become one of the most promising devices to replace conventional silicon-based solar cells and address current pressing energy *** them,the flexible PSCs are especially more widely applicable and may propel the rapid advancements of wearable electronics,causing a significant paradigm shift in consumer *** flexible PSCs use non-biodegradable petroleum-based polymer substrates,discarding of which will aggravate“white pollution”.Therefore,development of green,biodegradable and low-cost flexible substrates will provide a great alternative to flexible *** we have developed transparent nanocellulose paper(NCP)with coating of acrylic resin as substrates to fabricate flexible PSCs,which are biodegradable and easily *** PCE of these NCP-based PSCs reached 4.25%,while the power per weight(the ratio of power to device weight)was as high as 0.56 W g^(–1).The flexible PSCs also showed good stability,retaining>80%of original efficiency after 50 times of *** NCP-based substrates can also be applied to other electronic systems,which may prosper next-generation green flexible electronics.

关键词： transparent perovskite retaining