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The influence of nano-particle tracers on the slip length measurements by microPTV

Acta Mechanica Sinica 2013年第3期29卷 411-419页

作者： Xu zheng Gao-Pan Kong zhan-Hua Silber-Li State Key Laboratory of Nonlinear Mechanics Institute of MechanicsCAS

Direct measurement of slip length is based on the measured fluid velocity near solid boundary. However, previous micro particle image velocimetry/particle tracking velocimetry （microPIV/PTV） measurements have reported surprisingly large measured near-wall velocities of pressure-driven flow in apparent contradiction with the no-slip hy-pothesis and experimental results from other techniques. To better interpret the measured results of the microPIV/PTV, we performed velocity profile measurements near a hy-drophilic wall （z = 0.25-1.5 μm） with two sizes of tracer particles （φ 50 nm and φ200 nm）. The experimental results indicate that, at less than 1 μm from the wall, the deviations between the measured velocities and no-slip theoretical values obviously decrease from 93% of φ200 nm particles to 48% of φ50 nm particles. The Boltzmann-like exponential measured particle concentrations near wall were found. Based on the non linear Boltzmann distribution of particle concentration and the effective focus plane thickness, we illustrated the reason of the apparent velocity increase near wall and proposed a method to correct the measured velocity profile. By this method, the deviations between the corrected measured velocities and the no-slip theoretical velocity decrease from 45.8% to 10%, and the measured slip length on hy-drophilic glass is revised from 75 nm to 16 nm. These results indicated that the particle size and the biased particle concentration distribution can significantly affect near wall velocity measurement via microPIV/PTV, and result in larger measured velocity and slip length close to wall.

关键词： MicroPIV/PTV · Slip length · Nano-particle tracer · Particle concentration distribution · Boltzmann distribution

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Absolute control of helicity at the C-termini in quinoline oligoamide foldamers by chiral oxazolylaniline moieties

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Chinese Chemical Letters 2020年第3期31卷 673-676页

作者： Dan zheng Chengyuan Yu Lu zheng Yulin zhan Hua Jiang Department of Chemistry Beijing Normal UniversityBeijing 100875China

Absolute one-handed chiral quinoline tetramers andoctamers containing different oxazolylanilines at the C-terminus have been *** absolute one-handed sense and diastereomeric excess values were valued by^1H NMR.X-ray crystal diffractionand CD studies reveal that the S-oxazolylaniline always induces a P-handed helicity and the absolute helicity is driven by the stable three-center hydrogen bonding between protons in the amide and N atoms in oxazolylaniline and adjacent quinoline *** investigations demonstrated that S-CQn-a-d are CPL active and its g(lum)values are dependent on its ***,the sizes of the substituents in the chiral centers are different,howeve r,they exert no effect on the dissymmetric factors g(abs)and g(lum)of quinoline oligoamide foldamers.

关键词： Chiral induction Helical chirality Aromatic foldamer Circularly polarized luminescence Three-center hydrogen bonding

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Adversarial Attacks and Defenses in Deep Learning

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Engineering 2020年第3期6卷 346-360页

作者： Kui Ren Tianhang zheng zhan Qin Xue Liu Institute of Cyberspace Research Zhejiang UniversityHangzhou 310027China College of Computer Science and Technology Zhejiang UniversityHangzhou 310027China Department of Electrical and Computer Engineering University of TorontoTorontoON M5S 2E8Canada School of Computer Science McGill UniversityMontrealQC H3A 0E9Canada

With the rapid developments of artificial intelligence(AI)and deep learning(DL)techniques,it is critical to ensure the security and robustness of the deployed ***,the security vulnerability of DL algorithms to adversarial samples has been widely *** fabricated samples can lead to various misbehaviors of the DL models while being perceived as benign by *** implementations of adversarial attacks in real physical-world scenarios further demonstrate their ***,adversarial attack and defense techniques have attracted increasing attention from both machine learning and security communities and have become a hot research topic in recent *** this paper,we first introduce the theoretical foundations,algorithms,and applications of adversarial attack *** then describe a few research efforts on the defense techniques,which cover the broad frontier in the *** open problems and challenges are subsequently discussed,which we hope will provoke further research efforts in this critical area.

关键词： Machine learning Deep neural network Adversarial example Adversarial attack Adversarial defense

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Associations of land use around rail transit stations with jobs-housing distribution of rail commuters from smart-card data

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Geo-Spatial Information Science 2023年第3期26卷 346-361页

作者： Qingming zhan Yuqiu Jia Zhenhua zheng Qi zhang Lei Luo School of Urban Design Wuhan UniversityWuhanChina College of Tourism and Geographic Sciences Jilin Normal UniversitySipingChina Department of Technology Management Wuhan Land Use and Urban Spatial Planning Research CenterWuhanChina College of Architecture and Urban Planning Tongji UniversityShanghaiChina Faculty of Resources and Environmental Science Hubei UniversityWuhanChina

Previous studies generally used land use and travel flow to investigate the efficiency of the railway system in Transit-Oriented Development(TOD)***,to study the association of land use and jobs-housing distribution of commuters,we can find out the potential development of rail *** this research,four railway lines in Wuhan,China,were selected to explore the land use in promoting practical commuting population according to the smart-card data *** land use issues,except the road density and building density,a Normalized Location-Weighted Landscape Index(NLWLI)based on the source-sink theory in landscape ecology was established to assess the jobs-housing land use around rail transit ***,employment and housing details of commuters around rail transit stations were identified using smart-card *** found that the generation of commuting flow was affected by building density and the land use of employment in the immediate vicinity of rail transit *** distribution of building density and commuters in a mature rail line was roughly a normal ***,due to the inconsistency of land use and jobs-housing distribution around stations,the requirement of the balance of land use and jobs-housing distribution should be reduced at the scale of rail stations in the TOD planning *** study is the application of massive smart-card data in the field of urban *** identifies land use issues that affect rail transit commuting flow,and can help urban planners improve the efficiency of rail transit through planning and design.

关键词： Commuter jobs-housing ratio source-sink landscape TOD

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An approach for detecting LDoS attack based on cloud model

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Frontiers of Computer Science 2022年第6期16卷 123-134页

作者： Wei SHI Dan TANG Sijia zhan zheng QIN Xiyin WANG College of Computer Science and Electronic Engineering Hunan UniversityChangsha410082China

Cybersecurity has always been the focus of Internet *** LDoS attack is an intelligent type of DoS attack,which reduces the quality of network service by periodically sending high-speed but short-pulse attack *** of its concealment and low average rate,the traditional DoS attack detection methods are challenging to be *** existing LDoS attack detection methods generally have the problems of high FPR and FNR.A cloud model-based LDoS attack detection method is proposed,and a classifier based on SVM is used to train and classify the feature *** detection method is verified and tested in the NS2 simulation platform and Test-bed network *** with the existing research results,the proposed method requires fewer samples,and it has lower FPR and FNR.

关键词： cybersecurity LDoS attack cloud model SVM

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DYNAMICS OF α AND α' RELAXATION IN LAYERED SILICATE/POLYSTYRENE NANOCOMPOSITES STUDIED BY ANELASTIC SPECTROSCOPY

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Chinese Journal of Polymer Science 2013年第10期31卷 1334-1342页

作者： Shu-ying Shang zheng-ping Fang Institute of Polymer Composites Zhejiang University College of Physics & Information Engineering Henan Normal University Laboratory of Polymer Materials and Engineering Ningbo Institute of Technology Zhejiang University

The dynamics of polymer chains in layered silicate/polystyrene nanocomposites was studied by anelastic spectroscopy. Two thermal activated peaks （or and α＇ peaks） appeared when the specimens were heated to a high temperature and they were related to glass transition and liquid-liquid transition, respectively. The activation energy was calculated based on Arrhenius equation and it showed that the activation energy of glass transition （Eg） is much higher than that of liquid-liquid transition （EH）. Furthermore, the most interesting result for the activation energy was that there were two contrary trends for Eg and Ell, Eg decreased and Ell increased with the addition of clay platelets. The fragile parameter was analyzed and the variation of fragile parameters for the two transitions was also contrary to each other with the addition of clay platelets. All the results indicated that the confinement effect of clay platelets on the dynamics of polymer chain was scale dependent, and perhaps, the two transitions were produced by different mechanisms.

关键词： Dynamics Glass transiton Liquid-liquid transition Composites Confinement.

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An M-Objective Penalty Function Algorithm Under Big Penalty Parameters

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Journal of Systems Science & Complexity 2016年第2期29卷 455-471页

作者： zheng ying MENG Zhiqing SHEN Rui Basic College Ningbo Dahongying University College of Economics and Management Zhejiang University of Technology

Some classical penalty function algorithms may not always be convergent under big penalty parameters in Matlab software,which makes them impossible to find out an optimal solution to constrained optimization *** this paper,a novel penalty function(called M-objective penalty function) with one penalty parameter added to both objective and constrained functions of inequality constrained optimization problems is *** on the M-objective penalty function,an algorithm is developed to solve an optimal solution to the inequality constrained optimization problems,with its convergence proved under some ***,numerical results show that the proposed algorithm has a much better convergence than the classical penalty function algorithms under big penalty parameters,and is efficient in choosing a penalty parameter in a large range in Matlab software.

关键词： Algorithm constrained optimization problem M-objective penalty function stability.

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Human-Like Decision-Making of Autonomous Vehicles in Dynamic Traffic Scenarios

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IEEE/CAA Journal of Automatica Sinica 2023年第10期10卷 1905-1917页

作者： Tangyike zhang Junxiang zhan Jiamin Shi Jingmin Xin Nanning zheng National Key Laboratory of Human-Machine Hybrid Augmented Intelligence National Engineering Research Center for Visual Information and ApplicationsXi’an 710049 Institute of Artificial Intelligence and Robotics Xi’an Jiaotong UniversityXi’an 710049China Momenta Shanghai 201804China

With the maturation of autonomous driving technology, the use of autonomous vehicles in a socially acceptable manner has become a growing demand of the public. Human-like autonomous driving is expected due to the impact of the differences between autonomous vehicles and human drivers on *** human-like decision-making has become a research hotspot, a unified theory has not yet been formed, and there are significant differences in the implementation and performance of existing methods. This paper provides a comprehensive overview of human-like decision-making for autonomous vehicles. The following issues are discussed: 1) The intelligence level of most autonomous driving decision-making algorithms;2) The driving datasets and simulation platforms for testing and verifying human-like decision-making;3) The evaluation metrics of human-likeness;personalized driving;the application of decisionmaking in real traffic scenarios;and 4) The potential research direction of human-like driving. These research results are significant for creating interpretable human-like driving models and applying them in dynamic traffic scenarios. In the future, the combination of intuitive logical reasoning and hierarchical structure will be an important topic for further research. It is expected to meet the needs of human-like driving.

关键词： Autonomous vehicles decision-making driving behavior human-like driving

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Annotating the Literature with Disease Ontology

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Chinese Journal of Electronics 2017年第6期26卷 1261-1268页

作者： YANG Li ZHOU Yanhong zheng ying School of Computer and Communication Engineering Changsha University of Science and Technology School of Computer Science and Technology Huazhong University of Science and Technology

With the rapid growth of inquiry in biomedicine concerning diseases, the recognition of diseases becomes especially important. But only the recognition of the biomedical concepts in literature is not enough,annotations and normalizations of the concepts with normalized Metathesaurus get even more important. This paper proposes a system to annotate the literature with normalized Metathesaurus. First, a two-phase Conditional random fields(CRFs) is used to recognize the disease mentions, including the location and identification. Then, the paper adapts the Disease ontology(DO) to annotate the diseases recognized for normalization by computing the similarity between disease mentions and concepts. According to the similarities, the disease mentions are denoted as disease concepts and instances distinctively. The experiments carried out on the Arizona disease corpus show that our system makes a good achievement and outperforms the other works.

关键词： Text mining Disease ontology Annotation CRFs Dictionary Similarity

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Interlayer exciton formation,relaxation,and transport in TMD van der Waals heterostructures

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Light(Science & Applications) 2021年第5期10卷 720-748页

作者： ying Jiang Shula Chen Weihao zheng Biyuan zheng Anlian Pan Key Laboratory for Micro-Nano Physics and Technology of Hunan Province School of Physics and Electronicsand College of Materials Science and EngineeringHunan UniversityChangshaChina Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhanChina

Van der Waals(vdW)heterostructures based on transition metal dichalcogenides(TMDs)generally possess a type-II band alignment that facilitates the formation of interlayer excitons between constituent *** of the interlayer excitons in TMD vdW heterostructures holds great promise for the development of excitonic integrated circuits that serve as the counterpart of electronic integrated circuits,which allows the photons and excitons to transform into each other and thus bridges optical communication and signal processing at the integrated *** a consequence,numerous studies have been carried out to obtain deep insight into the physical properties of interlayer excitons,including revealing their ultrafast formation,long population recombination lifetimes,and intriguing spin-valley *** outstanding properties ensure interlayer excitons with good transport characteristics,and may pave the way for their potential applications in efficient excitonic devices based on TMD vdW *** present,a systematic and comprehensive overview of interlayer exciton formation,relaxation,transport,and potential applications is still *** this review,we give a comprehensive description and discussion of these frontier topics for interlayer excitons in TMD vdW heterostructures to provide valuable guidance for researchers in this field.

关键词： field. relaxation interlayer

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