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Regulatory T cells: immune suppression and beyond

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Cellular & Molecular Immunology 2010年第3期7卷 204-210页

作者： yisong y Wan Lineberger Comprehensive Cancer Center Department of Microbiology and ImmunologyThe University of North Carolina at Chapel HillSchool of MedicineNorth CarolinaNCUSA

Foxp3-expressing regulatory T cells(Tregs)were originally identified as critical in maintaining self-tolerance and immune *** immunosuppressive functions of Tregs are widely acknowledged and have been extensively *** studies have revealed many diverse roles of Tregs in shaping the immune system and the inflammatory *** review will discuss our efforts as well as the efforts of others towards understanding the multifaceted function of Tregs in immune regulation.

关键词： Foxp3 Treg immunosuppression and plasticity

Perception of Potential Health Risk of Climate Change and Utilization of Fans and Air Conditioners in a Representative Population of Hong Kong

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International Journal of Disaster Risk Science 2020年第1期11卷 105-118页

作者： yang Gao Emily y.y.Chan Holly C.y.Lam Aiwei Wang Department of Sport and Physical Education Hong Kong Baptist UniversityHong KongChina Collaborating Centre for Oxford University and CUHK for Disaster and Medical Humanitarian Response The Jockey Club School of Public Health and Primary CareThe Chinese University of Hong KongHong KongChina

Climate change, especially as reflected in heat waves, is a rising threat worldwide. Appropriate use of cooling devices can protect people from health impacts during a heat wave. A population-based telephone survey was conducted in a representative sample of residents in Hong Kong to investigate ownership and use of domestic cooling devices, identify correlates, and examine their associations with risk perception of potential health impact of climate change. More than 90% of the 1002 respondents owned and used cooling devices at home. The majority(57.7%) perceived the potential health risk of climate change at a high level. However, risk perception had no relationship with ownership and utilization of cooling devices. Old people(≥ 65 years), the low-educated, those with low income, and those with chronic diseases were more likely not to use air conditioners when feeling *** findings suggest that there are no signs showing people have taken more protective actions although half of respondents recognized climate change as a threat. Familial economic condition may be a major determinant in ownership and use of air conditioners at home. Old people and those with chronic diseases are at high risk of adverse exposure to climate change and therefore should be equipped with appropriate measures to use cooling devices.

关键词： Climate change Domestic cooling device Heat wave health impact Hong Kong Risk perception

Quantified evaluation of particle shape effects from micro-to-macro scales for non-convex grains

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Particuology 2016年第2期14卷 23-35页

作者： y. yang J.F. Wang y.M. Cheng Department of Civil and Environmental Engineering The Hong Kong Polytechnic University Hong Kong China Department of Civil and Architectural Engineering City University of Hong Kong Hong Kong China

Particle shape plays an important role in both the micro and macro scales responses of a granular assem- bly. This paper presents a systematic way to interpret the shape effects of granular material during quasi-static shearing. A more suitable shape descriptor is suggested for the quantitative analysis of the macroscale strength indexes and contact parameters for non-convex grains, with special consid- eration given to the peak state and critical state. Through a series of numerical simulations and related post-processing analysis, particle shape is found to directly influence the strain localisation patterns, microscale fabric distributions, microscale mobilisation indexes, and probability distribution of the nor- malised contact normal force. Additionally, the accuracy of the stress-force-fabric relationship can be influenced by the average normal force and the distribution of contact vectors. Moreover, particle shape plays a more important role than do the confining pressures in determining the friction angle. Strong force chains and the dilation effect are also found to be strongly influenced by the high confinin~ oressure.

关键词： Quantitative analysis Shape factor Statistical analysis Micro-macro indexes

A hybrid-stress solid-shell element for non-linear analysis of piezoelectric structures

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Science China(Technological Sciences) 2009年第3期52卷 575-583页

作者： SZE K y Department of Mechanical Engineering University of Hong Kong

This paper presents eight-node solid-shell elements for geometric non-linear analyze of piezoelectric structures. To subdue shear, trapezoidal and thickness locking, the assumed natural strain method and an ad hoc modified generalized laminate stiffness matrix are employed. With the generalized stresses arising from the modified generalized laminate stiffness matrix assumed to be independent from the ones obtained from the displacement, an extended Hellinger-Reissner functional can be derived. By choosing the assumed generalized stresses similar to the assumed stresses of a previous solid ele- ment, a hybrid-stress solid-shell element is formulated. The presented finite shell element is able to model arbitrary curved shell structures. Non-linear numerical examples demonstrate the ability of the proposed model to analyze nonlinear piezoelectric devices.

关键词： piezoelectric structures solid-shell element hybrid-stress geometric non-linear

Fabrication of multi-level 3-dimension microstructures by phase inversion process

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Nano-Micro Letters 2010年第2期2卷 95-100页

作者： y.Song Key Laboratory of Aerospace Materials and Performance (Education Ministry of China) Beihang University

One process based on phase inversion of fillers in microstructures for the fabrication of multi-level three-dimensional(3-D) microstructures is described using SU-8, a kind of epoxy photoresist, as the model constructing materials. This process is depicted by use of the routine photolithography technique to construct the top layer of 3-D microstructures on the bottom layer of 3-D microstructures layer by layer. This process makes it possible to fabricate multi-level 3-D microstructures with connectors at desired locations, and to seal long span microstructures(e.g. very shallow channels with depth less than 50 μm and width more than 300 μm) without blockage. In addition, this process can provide a sealing layer by the solidification of a liquid polymer layer, which can be as strong as the bulk constructing materials for microstructures due to a complete contact and cross-linking between the sealing layer and the patterned layers. The hydrodynamic testing indicates that this kind of sealing and interconnection can endure a static pressure of more than 10 MPa overnight and a hydrodynamic pressure drop of about 5.3 MPa for more than 8 hours by pumping the tetrahydrofuran solution through a 60 μm wide micro-channels.

关键词： Microstructures Multi-level Fabrication Photolithography Phase inversion Sealing

One-dimensional non-Darcy flow in a semi-infinite porous media:a multiphase implicit Stefan problem with phases divided by hydraulic gradients

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Acta Mechanica Sinica 2017年第5期33卷 855-867页

作者： G.Q.Zhou y.Zhou X.y.Shi State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and Technology School of Mechanics and Civil Engineering China University of Mining and Technology JiangSu Collaborative Innovation Center for Building Energy Saving and Construct Technology

One-dimensional non-Darcy flow in a semi-infinite porous media is investigated. We indicate that the non-Darcy relation which is usually determined from experimental results can always be described by a piecewise linear function, and the problem can be equivalently transformed to a multiphase implicit Stefan problem. The novel feature of this Stefan problem is that the phases of the porous media are divided by hydraulic gradients, not the excess pore water pressures. Using the similarity transformation technique, an exact solution for the situation that the external load increases in proportion to the square root of time is developed. The study on the existence and uniqueness of the solution leads to the requirement of a group of inequalities. A similar Stefan problem considering constant surface seepage velocity is also investigated, and the solution, which we indicate to be uniquely existent under all conditions, is established. Meanwhile, the relation between our Stefan problem and the traditional multiphase Stefan problem is demonstrated. In the end, computational examples of the solution are presented and discussed. The solution provides a useful benchmark for verifying the accuracy of general approximate algorithms of Stefan problems, and it is also attractive in the context of inverse problem analysis.

关键词： Moving boundary problem Stefan problem Analytical solution Non-Darcy flow Soil consolidation

Distinct Electrical and Mechanical Responses of a Cu-10Fe Composite Prepared by Hot-Pressed Sintering and Post Treatment

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Acta Metallurgica Sinica(English Letters) 2024年第2期37卷 255-265页

作者： X.y.yue S.y.Peng X.Zhang C.N.He y.Z.Tian Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education) School of Materials Science and EngineeringNortheastern UniversityShenyang110819China School of Materials Science and Engineering and Tianjin Key Laboratory of Composite and Functional Materials Tianjin UniversityTianjin300350China Research Centre for Metallic Wires Northeastern UniversityShenyang110819China

A Cu-10wt%Fe composite was prepared through hot-pressed sintering,and the material was subsequently solution *** hot-pressed sintered and solution treated materials were rolled and *** precipitation behavior and performance changes were systematically studied by using scanning electron microscopy and transmission electron *** contrast to the hot-pressed sintered specimen,the solution treatment significantly affects the thermal stability and properties of the Cu-10wt%Fe *** Cu-10wt%Fe composite was prepared after solid solution,cold rolling and aging at 773 K for 1 h,and it obtained excellent tensile strength of 494 MPa,uniform elongation of 16.3%,electrical conductivity of 51.1%IACS and softening temperature of 838 *** for the distinct difference in thermal stability and properties between hot-pressed sintered and solution treated specimens were *** findings provide a theoretical basis for designing high-performance Cu-based in-situ composites by post treatment.

关键词： Cu-Fe composite Hot-pressed sintering Thermal stability Strength Electrical conductivity

Corrosion behavior of 13Cr stainless steel under stress and crevice in high pressure CO_(2)/O_(2)environment

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Journal of Materials Science & Technology 2021年第29期88卷 79-89页

作者： G.y.Zhu y.y.Li B.S.Hou Q.H.Zhang G.A.Zhang Key Laboratory of Material Chemistry for Energy Conversion and Storage Ministry of EducationHubei Key Laboratory of Materials Chemistry and Service FailureSchool of Chemistry and Chemical EngineeringHuazhong University of Science and TechnologyWuhan430074China

In this work,through the self-developed setup for in situ electrochemical tests,the corrosion behavior of 13 Cr stainless steel under the combined effect of stress and crevice in high pressure CO_(2)/O_(2)environment was *** results show that 13 Cr stainless steel presents a self-passivation *** the action of stress,the anodic dissolution process of steel inside crevice is *** is a galvanic effect between the stressed steel inside crevice and the unstressed steel outside *** applied stress reduces the induction stage of crevice corrosion and induces a larger galvanic current,i.e.,the applied stress promotes the development of crevice ***,adding 0.1 MPa O_(2)is conducive to forming a more stable passive film but causes a greater galvanic effect.

关键词： Stainless steel Crevice corrosion Stress corrosion Galvanic effect

Improving maintenance efficiency and safety through a human-centric approach

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Advances in Manufacturing 2021年第1期9卷 104-114页

作者： C.y.Siew S.K.Ong A.y.C.Nee Graduate School for Integrative Sciences and Engineering National University of Singapore28 Medical DriveSingapore 117456Singapore Department of Mechanical Engineering National University of Singapore9 Engineering Drive 1Singapore 117576Singapore

This paper presents an adaptive human-machine interface(HMI)that can provide appropriate sets of digital maintenanceinformation and guidance to an operator during *** takes into consideration the expertise level of the operator and the maintenance context and *** proposed human-centric methodology considers the heart rate,intention,and expertise level of the operator,which can be captured using sensors during maintenance.A set of rules is formulated based on the sensor data to infer the state of the operator during a maintenance *** on the operator state,the adaptive HMI can augment the operator's senses using a scheme that combines visual,audio,and haptic guidance cues during maintenance to enhance the operator's ability to perceive information and perform maintenance *** schemes of visual,audio,and haptic cues are developed based on a comparison of the best practices obtained from experienced operators.

关键词： Augmented reality(AR) Ergonomics Product development Maintenance