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Mathematical modeling and full-scale shaking table tests for multi-curve buckling restrained braces

Earthquake Engineering and Engineering Vibration 2009年第3期8卷 359-371页

作者： c. S. Tsai Yungchang Lin Wenshin chen h. c. Su Department 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

Buckling restrained braces （BRBs） have been widely applied in seismic mitigation since they were introduced in the 1970s. however, traditional BRBs have several disadvantages caused by using a steel tube to envelope the mortar to prevent the core plate from buckling, such as： complex interfaces between the materials used, uncertain precision, and time consumption during the manufacturing processes. In this study, a new device called the multi-curve buckling restrained brace （Mc-BRB） is proposed to overcome these disadvantages. The new device consists of a core plate with multiple neck portions assembled to form multiple energy dissipation segments, and the enlarged segment, lateral support elements and constraining elements to prevent the BRB from buckling. The enlarged segment located in the middle of the core plate can be welded to the lateral support and constraining elements to increase buckling resistance and to prevent them from sliding during earthquakes. component tests and a series of shaking table tests on a full-scale steel structure equipped with Mc-BRBs were carried out to investigate the behavior and capability of this new BRB design for seismic mitigation. The experimental results illustrate that the Mc-BRB possesses a stable mechanical behavior under cyclic loadings and provides good protection to structures during earthquakes. Also, a mathematical model has been developed to simulate the mechanical characteristics of BRBs.

关键词： buckling restrained brace energy absorption passive control earthquake energy plasticity model structural control multi-curve BRB

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Effect of pre-deformation on microstructure and mechanical properties of WE43 magnesium alloy II: Aging at 250 and 300℃

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Journal of Magnesium and Alloys 2020年第1期8卷 103-110页

作者： Y.h.Kang Z.h.huang S.c.Wang h.Yan R.S.chen J.c.huang Guangdong-hong Kong Joint Research and Development center on Advanced Manufacturing Technology for Light Alloys Guangdong Institute of Materials and ProcessingGuangzhou 510650China Institute of Metal Research chinese Academy of Sciences Shenyang 110016China hong Kong Institute for Advanced Study Department of Materials Science and EngineeringCity University of Hong KongHong KongChina

In this work,the microstructural evolution and mechanical properties of a pre-deformed WE43 magnesium alloy when aged at 250 and 300℃ were further *** is found that the abundant deformation twins introduced by pre-deformation were maintained within the alloy during the aging *** particles formed at the twin boundaries and coarsened with aging time,especially at 300℃.When peak-aged at 250℃,the fine metastable β'''and β' precipitates formed in the un-deformed alloy have been transformed into relatively large β1 and β precipitates by the *** peak-aged at 300℃,the pre-deformation obviously refined the β *** properties indicate that pre-deformation can increase the yield strength by 19MPa and 54MPa for the peak-aged alloy at 250℃ and 300℃,respectively,and will not obviously deteriorate the tensile elongations.

关键词： WE43 magnesium alloy Pre-deformation Aging Microstructure Mechanical properties

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Simulating canopy stomatal conductance of winter wheat and its distribution using remote sensing information

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Journal of Environmental Sciences 2001年第4期13卷 439-443页

作者： Zhang, J.-h. Fu, c.-b. Kanzawa, h. START Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

The canopy stomatal movement, a plant physiological process, generally occurs within leaves but its influence on exchange of cO2, water vapor, and sensible heat fluxes between atmosphere and terrestrial ecosystem. Many studies have documented that the interaction between leaf photosynthesis and canopy stomatal conductance is obvious. Thus, information on stomatal conductance is valuable in climate and ecosystem models. In current study, a newly developed model was adopted to calculate canopy stomatal conductance of winter wheat in huang-huai-hai (h-h-h) Plain of china (31.5 - 42.7°N, 110.0 - 123.0°E). The remote sensing information from NOAA-AVhRR and meteorological observed data were used to estimate regional scale stomatal conductance distribution. canopy stomatal conductance distribution pattern of winter wheat on March 18, 1997 was also presented. The developed canopy stomatal conductance model might be used to estimate canopy stomatal conductance in land surface schemes and seems can be acted as a boundary condition in regional climatic model runs.

关键词： carbon dioxide Data reduction Ecosystems heat flux Meteorology Photosynthesis Physiology Plants (botany) Remote sensing Vapors

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SOME OBSERVATIONS ON DYNAMIc PROPERTIES OF REcEPTIVE FIELD ORGANIZATION OF cOMPLEX cELLS IN cAT VISUAL cORTEX

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Science china chemistry 1987年第1期30卷 44-54页

作者：李朝义,h.c.NOThDURFT Shanghai Institute of Physiology Academia Sinica Max-Planck-Institute for Biophysical chemistry Goettingen West Germany

The dynamic properties of discharge fields (DFs) of the complex cells in areas 17 and 18 of cat'sbrain were observed. The sequence of activation for different areas in the DF indicated a concentric ar-rangement of latency distribution. The DE organization was proved to be dependent closely cn velocityof stimulus movement. Twin-or triple-DFs were found for some cells, each responded selectively to oneof the opposite directions of movement.

关键词： SOME OBSERVATIONS ON DYNAMIc PROPERTIES OF REcEPTIVE FIELD ORGANIZATION OF cOMPLEX cELLS IN cAT VISUAL cORTEX DDF

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Functional gastrointestinal disorders in inflammatory bowel disease: Time for a paradigm shift?

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World Journal of Gastroenterology 2020年第26期26卷 3712-3719页

作者： Dipesh h Vasant Alexander c Ford Gastroenterology Manchester University NHS Foundation TrustWythenshawe HospitalManchester M239LTUnited Kingdom Division of Diabetes Endocrinology and GastroenterologyUniversity of ManchesterManchester M239LTUnited Kingdom Leeds Institute of Medical Research at St.James’s University of LeedsLeeds LS97TFUnited Kingdom Leeds Gastroenterology Institute Leeds Teaching Hospitals NHS TrustLeeds LS97TFUnited Kingdom

Recent advances in biological therapies have revolutionalised and redefined treatment targets in inflammatory bowel disease(IBD).There is now a stronger emphasis on achieving the more stringent therapeutic goals of mucosal and histological healing,rather than clinical remission ***,the treatment of refractory“functional”gastrointestinal symptoms,often attributed as the aftermath of previous inflammation,has recently become more prominent in quiescent *** further expected advances in anti-inflammatory treatments on the horizon,the burden of such symptoms in quiescent disease,which have been relatively neglected,is set to become an even bigger *** this article,we highlight the current state of research and understanding in this field,including recent developments and clinical practice guidelines on the diagnosis and management of functional gastrointestinal symptoms,such as irritable bowel syndrome and functional anorectal and pelvic floor disorders,in patients with quiescent *** disorders are not only highly prevalent in these patients,they are often misdiagnosed,and are difficult to treat,with very few evidence-based ***,they are associated with substantial impairment in quality-of-life,considerable morbidity,and psychological *** is therefore an urgent need for a change in emphasis towards earlier recognition,positive diagnosis,and targeted treatment for patients with ongoing functional gastrointestinal symptoms in the absence of active *** article also highlights the need for further research to develop much needed evidence-based therapies.

关键词： Irritable bowel syndrome Inflammatory bowel disease Functional gastrointestinal disorders Faecal incontinence Pelvic floor dyssynergia

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Plasma density measurement and downstream etching of silicon and silicon oxide in Ar/NF3 mixture remote plasma source

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Plasma Science and Technology 2019年第6期21卷 52-57页

作者： h J YEOM D h chOI Y S LEE J h KIM D J SEONG S J YOU h c LEE Korea Research Institute of Standards and Science(KRISS) Daejeon 34113 Republic of Korea Department of Physics Chungnam National University Daejeon 34134 Republic of Korea

In this study,plasma density measurements were performed near the plume region of the remote plasma source (RPS) in Ar/NF3 gas mixtures using a microwave cutoff *** measured plasma density is in the range of 1010-1011 cm-3 in the discharge conditions with RPS powers of 2-4 kW and gas pressures of 0.87-4 *** plasma density decreased with increasing gas pressures and RPS powers under various Ar/NF3 mixing *** decrease in the plasma density measured at the fixed measurement position (plume region) can be understood by the reduction of the electron energy relaxation length with increases in the gas pressures and mixing ratio of NF3/(Ar/NF3).We also performed downstream etching of silicon and silicon oxide films in this *** etch rate of the silicon films significantly increases while the silicon oxide is slightly etched with the gas pressures and *** was also found that the etch rate strongly depends on the wafer position on the processing chamber electrode,and that the etch selectivity reached 96-131 in the discharge conditions of RF powers (3730-4180 W) and gas pressures (3.6-4 Torr).

关键词： remote plasma source electron density cutoff probe downstream etch

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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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AN ADAPTIVE EFG-FE cOUPLING METhOD FOR ThE NUMERIcAL SIMULATION OF EXTRUSION PROcESSES

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Acta Metallurgica Sinica(English Letters) 2008年第5期21卷 380-388页

作者： L.c. Liu X.h. Doug c.X. Li National Die ＆ Mold cAD Engineering Research center Shanghai Jiaotong University Shanghai 200030 China

An adaptive EFG-FE coupling method is proposed and developed for the numerical simulation of lateral extrusion and forward-backward extrusion. Initially, the simulation has been implemented by using a conventional FE model. During the deforming process, mesh quality is checked at every incremental step. Distorted elements are automatically converted to EFG nodes, whereas, the less distorted elements are reserved. A new algorithm to generate EFG nodes and interface elements is presented. This method is capable of dealing with large deformation and has higher computational efficiency than using an EFG method wholly. Numerical results demonstrate that the adaptive EFG-FE coupling method has reasonable accuracy and is effective for local bulk metal forming such as extrusion processes.

关键词： Meshless method coupling method Numerical simulation Extrusion process

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Influence of Tropical cyclones on hong Kong Air Quality

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Advances in Atmospheric Sciences 2018年第9期35卷 1177-1188页

作者： Eric c.h.chOW Richard c.Y.LI Wen ZhOU city University of hong Kong(Shenzhen)Research Institute Shenzhen 518057China Guy carpenter Asia-Pacific climate Impact center School of Energy and Environment City University of Hong KongHong KongChina

Tropical cyclones（Tcs） constitute one of the major atmospheric activities affecting the air quality of the Pearl River Delta region. In this study, the impact of Tcs on air quality in hong Kong during the Tc active season（July–October） from 2000 to 2015 is investigated. It is found that 57.5% of days with concentration of particulate matter with an aerodynamic diameter 10 μm（PM（10）） above the 90th percentile are related to Tc activity. Tcs in three regions, located to the east, southeast, and southwest of hong Kong, have obvious impacts on pollutant concentration. When Tcs are located east of hong Kong near Taiwan, 65.5%/38.7% of the days have high or extremely high PM（10）/ozone（O3） levels, which are associated with northerly wind, sinking motion, and relatively low precipitation. When Tcs are located southeast of hong Kong, 48.1%/58.2% of the days have high pollution levels, associated mainly with continental air mass transport. When Tcs are south or west of hong Kong, only 20.8%/16.9% of the days have high PM（10）/O3 levels, and the air quality in hong Kong is generally good or normal due to Tc-associated precipitation, oceanic air mass transport, and an enhanced rising motion. The higher chance of high O3 days when Tcs are present between hong Kong and Taiwan, possibly due to lower-than-normal precipitation along the east coast of china under Tc circulation. The results in this study highlight the important influence of Tc position and associated atmospheric circulations on the air quality in hong Kong.

关键词： PM10 03 air quality hK Tc

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herbivory of sympatric elk and cattle on Lincoln National Forest,south-central New Mexico

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Forest Ecosystems 2015年第4期2卷 314-326页

作者： heather h.halbritter Louis c.Bender Extension Animal Sciences and Natural Resources New Mexico State University

Background： Wildlife and livestock grazing are important products of forest ecosystems, but can be controversial. herbivory by North American elk and domestic cattle is a contentious management issue throughout western North America, often driving management proposals to decrease cattle and elk numbers based on perceived overutilization of forages. Such observations are often site level rather than landscape, and may confuse ecological sustainability with desired conditions. Methods： We used line transects to document vegetation composition, structure, and grazing and browsing utilization for 4 key habitat types： mountain meadows, aspen, thinned conifer, and burned conifer on Lincoln National Forest, New Mexico, USA. We documented relative habitat use of these types by elk, mule deer, and cattle and modeled relative use on residual grass biomass of mountain meadows and browse utilization of forested types. We determined diets and diet quality of elk and cattle to assess degree of competition. Results： Use of grasses in meadows was below management thresholds, and combined elk, cattle, and deer relative habitat use accounted for 〈 14 % of the variance in residual stubble height of Poa protensis, the most abundant grass. Palatable browse was limited in habitat types （〈 107 ***^-1）, use was generally high, and elk presence was correlated with the majority of browsing. Elk and cattle diets did not significantly overlap （Schoener＇s index 0.54-0.57）; elk fed primarily on deciduous shrubs （34 %-55 % of annual diets） and cattle on grass （72 %-77 %）. Digestibility and crude protein levels of cattle diets and body condition of elk indicated high quality diets for cattle and marginal-good quality diets for elk. conclusions： At observed stocking levels and densities, cattle and elk were not competing for forage based on diet similarity, nor were key habitat types being used beyond sustainable levels. Low browse availability indicates that opportunity exists to increase for

关键词： Browsing cattle carrying capacity Elk Grazing herbivory Nutrition

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