检索结果-南通市图书馆

A new methodology for energy-based seismic design of steel moment frames

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2017年第1期16卷 131-152页

作者： Mebrahtom Gebrekirstos Mezgebo Eric M. lui Michael Baker International Hamilton NJ 08619 USA Department of Civil and Environmental Engineering Syracuse University Syracuse NY 13244-1240 USA

A procedure is proposed whereby input and hysteretic energy spectra developed for single-degree-of-freedom （SDOF） systems are applied to multi-degree-of-freedom （MDOF） steel moment resisting frames. The proposed procedure is verified using four frames, viz., frame with three-, five-, seven- and nine-stories, each of which is subjected to the fault- normal and fault-parallel components of three actual earthquakes. A very good estimate for the three- and five-story frames, and a reasonably acceptable estimate for the seven-, and nine-story frames, have been obtained. A method for distributing the hysteretic energy over the frame height is also proposed. This distribution scheme allows for the determination of the energy demand component of a proposed energy-based seismic design （EBSD） procedure for each story. To address the capacity component of EBSD, a story-wise optimization design procedure is developed by utilizing the energy dissipating capacity from plastic hinge formation/rotation for these moment frames. The proposed EBSD procedure is demonstrated in the design of a three-story one-bay steel moment frame.

关键词： energy-based seismic design hysteretic energy distribution MDOF systems steel moment frames story-wise optimization design

Prescription practice of antihistamines for acute upper respiratory tract infections in pediatric patients in a local emergency department in Hong Kong

在线全文

学校读者我要写书评

暂无评论

World Journal of Emergency Medicine 2017年第1期8卷 47-54页

作者： Chun Tat lui Department of Accident and Emergency Medicine Tuen Mun HospitalHong KongChina

BACKGROUND: Currently there is very limited data in the literature assessing the prevalence of antihistamine prescription, and there is no local prevalence data about the prescription of antihistamine agents among primary practitioner and emergency physicians. The objectives are 1) to report the prevalence of antihistamine prescription for children less than 6 years old with acute upper respiratory infection and 2) to explore the associated factors for the prescription ***: This is a cross-sectional study. All consecutive cases of paediatric patients aged 6 or below who presented to the emergency department during a study period of one week from April 1 to July 4, 2009 with diagnosis of acute upper respiratory infection were included. Totally 162 patients were ***: Among the 162 cases, 141(87%) patients were prescribed one antihistamine of any group. Sixty(37%) patients were prescribed two or more antihistamines. In multivariate logistic regression model, age was found to be signi? cantly(P<0.001) associated with multiple antihistamine prescription(OR=1.042, 95%CI=1.02 to 1.06). Years of graduation of attending physician for more than 5 years was also a strong predictor of multiple antihistamine prescription(OR=4.654, 95%CI=2.20 to 9.84, P<0.001).CONCLUSION: In the local emergency department, patients' age and the years of graduation from medical school of the attending physician were predictors of multiple antihistamine prescription for acute upper respiratory infections for children aged less than 6.

关键词： Upper respiratory infections Respiratory tract infections Common cold Drug prescription Drug utilization Prescription practice Antihistamine Histamine antagonist Children

Imaging global auroras in space

在线全文

学校读者我要写书评

暂无评论

Light(Science & Applications) 2019年第1期8卷 452-453页

作者： A.T.Y.lui JHU/APL LaurelMD 20723-6099USA

China’s initial participation in the global monitoring of auroras for scientific and space weather investigations has been enabled by the successful launch of the Chinese Fengyun-3D satellite,which carries a wide-fie... 详细信息

关键词： weather global space

Fatty acids and algal lipids as precursors of chlorination by-products

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2012年第11期24卷 1942-1946页

作者： Yan Liang Yuen Shan lui Huachang Hong Croucher Institute for Environmental Sciences(CIES)and Department of Biology Hong Kong Baptist UniversityKowloon TongHong KongChina College of Geography and Environmental Sciences Zhejiang Normal UniversityJinhua 321004China Centre for Food Safety and Environmental Technology Guangzhou Institute of Advanced TechnologyChinese Academy of SciencesGuangzhou 511458China

Six common algal fatty acids （FAs） with different numbers of double bonds, lipophilic fractions and proteins extracted from the diatom Navicula pelliculosa and algal ceils were chlorinated to evaluate their potential in generating disinfection by-products （DBPs）. The result showed that the more double bonds in the FAs, the higher the amounts of chloroform and dichloroacetic acid （DCAA） produced, but such a pattern was not observed for trichloroacetic acid （TCAA）. Based on the previously reported composition of fatty acids in algal lipids, the DBP generation potentials of algal lipids were calculated. These predicted values were much lower than those measured in the chlorinated algal lipophilic fraction, suggesting unknown lipophilic fraction（s） served as potent DBPs precursors. Another calculation attempted to predict DBP production in algal cells based on algal lipid and protein composition, given quantified measured DBP production per unit algal lipid and proteins. The analysis showed that the observed DBP production was similar to that predicted （〈 35% difference）, suggesting that algal biochemical compositions may serve as a bioindicator for preliminary estimation of chloroform, DCAA and TCAA formation upon chlorinating algae.

关键词： algal lipid algal-derived organic materials chlorination by-products fatty acids

Rational design of photoelectrodes for photoelectrochemical water splitting and CO2 reduction

在线全文

学校读者我要写书评

暂无评论

Frontiers of physics 2019年第5期14卷 19-36页

作者： Yu Hui lui Bowei Zhang Shan Hu Department of Mechanical Engineering Iowa State UniversityAmesIA 50011USA

Solar energy has promising potential for building sustainable *** of solar energy into solar fuels plays a crucial role in overcoming the intennittent nature of the renewable energy source.A pliotoclectrochernical (PEC) cell that employs semiconductor as photoelectrode to split water into hydrogen or fixing carbon dioxide (CO2) into hydrocarbon fuels provides great potential to achieve zcrocarbon-oiiiission society.A proper design of those semiconductor photoelectrodes thus directly influences the performance of the PEC *** this review,we investigate the strategics that have been put towards the design of efficiont photoelectrodes for PEC water splitting and CO2 reduction in recent years and provide sonic future design directions toward noxt-goneration FEC cells for water splitting and CO2 reduction.

关键词： photoelectrochemistry water splitting CO2 reduction

Enhancing work hardening and ductility in additively manufacturedβTi:roles played by grain orientation,morphology and substructure

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2022年第10期105卷 131-141页

作者： Ahmad Zafari Edward Wen Chiek lui Mogeng Li Kenong Xia Department of Mechanical Engineering The University of MelbourneVictoria 3010Australia Centre for Additive Manufacturing School of EngineeringRMIT UniversityMelbourneVIC 3000Australia Physics of Fluids Group Max Planck Center for Complex Fluid DynamicsJ.M.Burgers Center for Fluid Dynamics and MESA+Research InstituteDepartment of Science and TechnologyUniversity of Twente7500AE Enschedethe Netherlands

A metastableβTi alloy was additively manufactured by laser powder bed fusion(LPBF).Tensile testing along the build direction of the as-LPBF material(LPBF-0°)revealed signifcant work softening immediately following yielding with no uniform *** contrast,substantial work hardening and uniform elongation well over 10%were achieved perpendicular to the build direction(LPBF-90°).Similar effects were obtained in the build direction after super transus heat treatment(LPBF-0°+HT)although the strength was slightly *** addition,the yield drop phenomenon observed in both orientations of the as-LPBF materials disappeared after *** enhanced work hardening ability,and thus ductility,can be attributed to increased interactions of slip bands/slip bands owing to additional{112}slip systems becoming operative in LPBF-0°+HT and LPBF-90°while LPBF-0°was dominated by{110}*** other variations after HT may be related to the coarsening of grain structure and removal of specifc substructures in the as-LPBF microstructure.

关键词： βtitanium Work hardening Anisotropy Equiaxed microstructure Slip band Laser powder bed fusion

A step through the looking glass

在线全文

学校读者我要写书评

暂无评论

Science China(Life Sciences) 2016年第9期59卷 979-980页

作者： Youyun Liang Ee lui Ang Huimin Zhao Metabolic Engineering Research Laboratory Science and Engineering InstitutesAgency for Science Technology and Research Department of Chemical and Biomolecular Engineering University of Illinois at Urbana-Champaign

Despite our many advances in deconstructing and understanding cellular and biomolecular machineries,the homochirality of life remains an *** our earliest ancestors,the central dogma has operated solely on D-DNA

关键词：镜子分子机器中心法则

Internal States of Temperature Hysteresis in Shape Memory Alloys

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 1997年第3期13卷 206-210页

作者： Xu, HB Gong, sk Dept. of Materials Science and Engineering Beijing University of Aeronautics and Astronautics Beijing 100083 China

We propose a thermodynamic theory that permits us to connect the size of the temperature hysteresis loop to the interfacial energy between martensite and austenite. The free energy is a function of four variables, viz. deformation of austenite, deformation of martensite, phase fraction and temperature. A diagonal line inside the hysteresis loop in the deformation-temperature diagram is identified as the line of unstable phase equilibrium. Upon reaching this line the phase mixture loses its (meta-)stability, and the transformation from one phase to the other should occur. The theoretical results are supported by experiments on NiTi and CuAlNi specimens.

关键词： Shape memory effect

Radial basis function‐based exoskeleton robot controller development

在线全文

学校读者我要写书评

暂无评论

IET Cyber-Systems and Robotics 2022年第3期4卷 228-250页

作者： sk Hasan Department of Mechanical and Manufacturing Engineering Miami UniversityOxfordOhioUSA

The realisation of a model‐based controller for a robot with a higher degree of freedom requires a substantial amount of computational power.A high‐speed CPU is required to maintain a higher sampling *** processors cannot boost the performance or reduce the execution time as the programs are sequentially *** neural network is a great tool to convert a sequentially structured program to an equivalent parallel architecture *** this study,a radial basis function(RBF)neural network is developed for controlling 7 degrees of freedom of the human lower extremity exoskel-eton robot.A realistic friction model is used for modelling joint *** trajectory tracking accuracies have been *** of computational efficiency has been *** stability analysis of the developed controller is *** of variance is used to assess the controller's resilience to parameter *** show the effectiveness of the developed controller,a comparative study was performe between the developed RBF network‐based controller and Sliding Mode Controller,Computed Tor-que Controller,Adaptive controller,Linear Quadratic Regulator and Model Reference Computed Torque Controller.

关键词： exoskeleton robot dynamic modelling lower extremity exoskeleton robot control radial basis function(RBF)controller