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Evaluating the Origin Intensity Factor in the Singular Boundary Method for Three-Dimensional Dirichlet Problems

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Advances in Applied Mathematics and Mechanics 2017年第6期9卷 1289-1311页

作者： Linlin Sun wen Chen Alexander h-D.Cheng State Key Laboratory of hydrology-Water Resources and hydraulic Engineering International Center for Simulation Software in Engineering and SciencesCollege of Mechanics and MaterialsHohai UniversityNanjing 210098China Department of Computational Science and Statistics School of ScienceNantong UniversityNantongJiangsu 226019China School of Engineering University of MississippiUniversityMS 38677USA

In this paper,a new formulation is proposed to evaluate the origin intensity factors(OIFs)in the singular boundary method(SBM)for solving 3D potential problems with Dirichlet boundary *** SBM is a strong-form boundary discretization collocation technique and is mathematically simple,easy-to-program,and free of *** crucial step in the implementation of the SBM is to determine the OIFs which isolate the singularities of the fundamental ***,the inverse interpolation technique(IIT)is adopted to calculate the OIFs on Dirichlet boundary,which is time consuming for large-scale *** recent years,the new methodology has been developed to efficiently calculate the OIFs on Neumann boundary,but the Dirichlet problem remains an open *** study employs the subtracting and adding-back technique based on the integration of the fundamental solution over the whole boundary to develop a new formulation of the OIFs on 3D Dirichlet *** problems with varied domain shapes and boundary conditions are carried out to validate the effectiveness and feasibility of the proposed scheme in comparison with the SBM based on inverse interpolation technique,the method of fundamental solutions,and the boundary element method.

关键词： Origin intensity factors singular boundarymethod boundary-typemeshlessmethod potential problem fundamental solution

Tri-directional shaking table tests of vibration sensitive equipment with static dynamics interchangeable-ball pendulum system

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Earthquake Engineering and Engineering Vibration 2010年第1期9卷 103-112页

作者： C.S. Tsai Yung-Chang Lin wen-Shin Chen h.C. Su D g epartment of Civil Engineering Feng Chia University Taichung Chinese Taipei graduate Institute of Civil and hydraulic Engineering Feng Chia University Taichung Chinese Taipei Department of Water Resources Engineering and Conservation Feng Chia University Taichung Chinese Taipei

Recently, the high-tech industry has become a key industry for economic development in many countries. however, vibration sensitive equipment located in these industrial buildings is vulnerable during earthquakes, which may cause huge economic loss. In this study, an innovative isolator for safeguarding the vibration sensitive equipment, namely, the static dynamics interchangeable^all pendulum system （SDI-BPS） is proposed and investigated to examine its protective capability for the vibration sensitive equipment during earthquakes through a series of tri-directional shaking table tests. The experimental results illustrate that the SDI-BPS isolator can provide significant damping to rolling types of base isolation systems for reducing the bearing displacement and size, and avoid the stress concentration, which can cause damage or scratches on the rolling surface of the isolator, to prolong its life span of service. The SDI-BPS isolator also provides excellent capability in protecting the vibration sensitive equipment and exhibits a stable behavior under long terms of service loadings and earthquakes.

关键词： ball pendulum system critical equipment base isolation vibration sensitive equipment base isolator passive control earthquake engineering structural control

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Experimental investigation of laser surface processing of flexure silicon nitride ceramic

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中国有色金属学会会刊：英文版 2006年第B02期16卷 558-565页

作者： SUN Li A. P. MALShE JIANg wen-ping P. h. MCCLUSKEY Department of Mechanical Engineering University of Arkansas Fayetteville AR 72701 USA Technology ＆ Solutions Division Caterpillar Inc. Peoria IL 61629 USA

A continuous wave carbon dioxide (CO2) laser (λ=10.6μm) was employed to treat the surface of Si3N4 MOR (modulus of rupture) bars. The effects of the CO2 laser process on physical and mechanical properties of ground Si3N4 samples were investigated. Scanning electron microscopy (SEM) analysis shows that the area occupied by cavities and fracture is decreased by about 49.4% after laser treatments. Cross-sectional metallography results indicate that the secondary YSiAlON phase in the Si3N4 ceramic is softened/melted and flowed into the defects. Four-point bending tests show that the flexural strength of the treated samples is improved to 10.9%. Fractographic analysis show that the fracture origins move from the surface to subsurface. It is concluded that laser surface processing have significant effects on fracture behavior of flexure Si3N4 ceramic.

关键词：氮化硅陶瓷激光表面处理实验研究挠曲强度物理性质

Tensile and shearing behaviors of the particle raft

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Acta Mechanica Sinica 2021年第6期37卷 904-909,I0001页

作者： P.C.Zuo h.Yu J.L.Liu Z.J.wen College of Pipeline and Civil Engineering China University of Petroleum(East China)Qingdao266580China School of Science China University of Petroleum(East China)Qingdao266580China Key Laboratory of Mining Disaster Prevention and Control Shandong University of Science and TechnologyQingdao266590China

The particle raft is a two-dimensional condensed soft matter,which is composed of hydrophobic solid particles floating on a liquid *** this study,we have realized to conduct tension and shear experiments on the particle raft by using the self-assembled loading *** crack initiation and propagation are observed by the camera,and the curve of the non-dimensional force with respect to the displacement is *** experimental results have been compared with the particle flow code 3D(PFC3D)simulation,and they are in excellent *** indicates that the particle raft possesses mechanical properties between solid and *** findings provide some inspirations on engineering new devices and new materials at the microscale.

关键词： Particle raft Tension Shear Crack Force–displacement curve

Fabrication of all-transparent polymer-based and encapsulated nanofluidic devices using nano-indentation lithography

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Microsystems & Nanoengineering 2017年第1期3卷 373-381页

作者： Cong Wu Tiffany g.Lin Zhikun Zhan Yi Li Steve C.h.Tung William C.Tang wen J.Li Department of Mechanical and Biomedical Engineering City University of Hong KongHong Kong 999077China Department of Biomedical Engineering University of CaliforniaIrvineCA 92697-2715USA Department of Automation Yanshan UniversityQinghuangdao 066004China Department of Mechanical Engineering University of ArkansasFayettevilleAR 72701USA

In this paper,we describe a novel and simple process for the fabrication of all-transparent and encapsulated polymeric nanofluidic devices using nano-indentation ***,a nanomechanical probe is used to‘scratch’nanoscale channels on polymethylmethacrylate(PMMA)substrates with sufficiently high ***,polydimethylsiloxane(PDMS)is used twice to duplicate the nanochannels onto PDMS substrates from the‘nano-scratched’PMMA substrates.A number of experiments are conducted to explore the relationships between the nano-indentation parameters and the nanochannel dimensions and to control the aspect ratio of the fabricated *** addition,traditional photolithography combined with soft lithography is employed to fabricate microchannels on another PDMS‘cap’*** manually aligning the substrates,all uncovered channels on two separate PDMS substrates are bonded to achieve a sealed and transparent nanofluidic device,which makes the dimensional transition from microscale to nanoscale *** smallest dimensions of the achievable nanochannels that we have demonstrated thus far are of~20 nm depth and~800 nm width,with lengths extendable beyond 100μ*** flow experiments are performed to verify the reliability of the *** types of colloidal solution are used to visualize the fluid flow through the nanochannels,that is,ethanol is mixed with gold colloid or fluorescent dye(fluorescein isothiocyanate),and the flow rate and filling time of liquid in the nanochannels are estimated based on time-lapsed image *** simplicity of the fabrication process,bio-compatibility of the polymer substrates,and optical transparency of the nanochannels for flow visualization are key characteristics of this approach that will be very useful for nanofluidic and biomolecular research applications in the future.

关键词： indentation lithography nanochannel nanofluidic device nanofluidic flow

Implicit Function Based Open-loop Analysis Method for Detecting the SSR Using Identified System Parameters

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CSEE Journal of Power and Energy Systems 2024年第5期10卷 2016-2026页

作者： Luonan Qiu Tianhao wen Yang Liu Q.h.Wu School of Electric Power Engineering South China University of TechnologyGuangzhou 510640China

This paper proposes an implicit function based open-loop analysis method to detect the subsynchronous resonance(SSR),including asymmetric subsynchronous modal attraction(ASSMA)and asymmetric subsynchronous modal repulsion(ASSMR),of doubly-fed induction generator based wind farms(DFIg-WFs)penetrated power *** some important parameters of DFIg-WF are difficult to obtain,reinforcement learning and least squares method are applied to identify those important *** predicting the location of closed-loop subsynchronous oscillation(SSO)modes based on the calculation of partial differentials of characteristic equation,both ASSMA and ASSMR can be *** proposed method in this paper can select SSO modes which move to the right half complex planes as control parameters ***,the proposed open-loop analysis method is adaptive to parameter *** studies are carried out on the 4-machine 11-bus power system to verify properties of the proposed method.

关键词： Open-loop modal analysis reinforcement learning based parameter identification subsynchronous resonance

Foot use and hand preference during feeding in captive black-and-white snub-nosed monkeys(Rhinopithecus bieti)

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Integrative Zoology 2013年第4期8卷 378-388页

作者： Jing PAN wen XIAO Matthew h.TALBERT Matthew B.SCOTT Institute of Eastern-himalaya Biodiversity Research Dali UniversityDaliYunnanChina Department of Psychology University of GeorgiaAthensGeorgiaUSA School of Life Sciences University of Science and Technology of ChinaHefeiAnhuiChina Kunming Institute of Zoology Chinese Academy of SciencesKunmingYunnanChina College of Engineering University of GeorgiaAthensGeorgiaUSA

Postural origin theory predicts that body postures are related to hand preference in nonhuman primates due to hemispheric *** preference,especially in manipulating objects,is also a good predictor of hemispheric specialization in *** studied limb(hand and foot)preferences in 11 captive adult black-and-white snub-nosed monkeys(Rhinopithecus bieti)to see how limb preference is influenced by postures and foot *** preference was significantly different for this group between quadrupedal standing and clinging postures,and sitting and clinging postures,but not between bipedal standing and clinging *** were significantly more likely to use the right hand in the clinging posture than in quadrupedal standing or sitting *** the sitting posture,individuals maintained their respective hand preference even when the food was on the other side of the *** was a gender difference in the sitting posture,where females preferred their right hand but males preferred their *** who did not routinely use their feet to manipulate objects,compared to those who did,shifted to greater right hand use from the clinging posture to the bipedal *** male individual and his offspring were more likely to use their feet to manipulate objects than the rest of the *** the present study,we reveal the first evidence of a postural effect on hand preference in *** as well as a foot preference in this *** results mostly agree with the postural origin theory and hemispheric specialization.

关键词： bipedal standing foot preference gender difference limb preference postural origin theory

Intraseasonal Variation of Visibility in hong Kong

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Advances in Atmospheric Sciences 2017年第1期34卷 26-38页

作者： wen ZhOU Richard C.Y.LI Eric C.h.ChOW guy Carpenter Asia-Pacific Climate Impact Center School of Energy and EnvironmentCity University of Hong KongHong KongChina City University of hong Kong Shenzhen Research Institute Shenzhen518057China

Visibility is one of the parameters for indicating air pollution. In this study, visibility variation in hong Kong during summer and winter is investigated. Visibility in hong Kong has clear intraseasonai variation. Examination of different environmental parameters suggests that the intraseasonal component dominates the overall circulation anomalies in both summer and winter. Associated with the intraseasonal variation of environmental parameters, obvious variation in visibility impair- ment is found in both summer and winter. In summer, local visibility and air quality are found to be significantly affected by the （MJO） and the 10-30-day intraseasonal oscillation （ISO） through modulation of associated atmospheric circulations. In winter, the modulation effects appear to be weaker due to the southward shift of the associated convection. The results in this study highlight the importance of the ISO in contributing to the overall variation in visibility in hong Kong, and provide useful implications for the development of possible mitigation strategies associated with visibility impairment and air pollution in hong Kong.

关键词： visibility intraseasonal oscillation air quality hong Kong

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Remarkable Link between Projected Uncertainties of Arctic Sea-Ice Decline and Winter Eurasian Climate

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Advances in Atmospheric Sciences 2018年第1期35卷 38-51页

作者： hoffman h.N.ChEUNg Noel KEENLYSIDE Nour-Eddine OMRANI wen ZhOU geophysical Institute University of BergenBergen 5007Norway Bjerknes Centre for Climate Research University of BergenBergen 5007Norway Nansen Environmental and Remote Sensing Center Bergen 5006Norway guy Carpenter Asia-Pacific Climate Impact Centre School of Energy and EnvironmentCity University of Hong KongHong KongChina City University of hong Kong Shenzhen Research Institute Shenzhen 518057China

We identify that the projected uncertainty of the pan-Arctic sea-ice concentration(SIC) is strongly coupled with the Eurasian circulation in the boreal winter(December–March; DJFM), based on a singular value decomposition(SVD) analysis of the forced response of 11 CMIP5 models. In the models showing a stronger sea-ice decline, the Polar cell becomes weaker and there is an anomalous increase in the sea level pressure(SLP) along 60°N, including the Urals–Siberia region and the Iceland low region. There is an accompanying weakening of both the midlatitude westerly winds and the Ferrell cell,where the SVD signals are also related to anomalous sea surface temperature warming in the midlatitude North *** the Mediterranean region, the anomalous circulation response shows a decreasing SLP and increasing precipitation. The anomalous SLP responses over the Euro-Atlantic region project on to the negative North Atlantic Oscillation–like ***, pan-Arctic SIC decline could strongly impact the winter Eurasian climate, but we should be cautious about the causality of their linkage.

关键词： Arctic climate Siberian high Icelandic low three-cell meridional circulation

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