检索结果-南通市图书馆

Adsorption thermodynamics and kinetic investigation of aromatic amphoteric compounds onto different polymeric adsorbents

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2007年第11期19卷 1298-1304页

作者： WANG Hal-ling FEI Zheng-hao CHEN jin-long ZHANG quan-xing XU Yan-hua College of Environment Nanjing University of Technology Nanjing 210009 China Jiangsu Provincial Key Laboratory of Coastal Wetland Bioresources and Environmental Protection Yancheng 224002 China State Key Laboratory of Pollution Control and Resources Reuse School of Environment Nanjing University Nanjing 210093 China

The adsorption behavior ofp-aminobenzoic acid and o-aminobenzoic acid onto the different polymeric adsorbents was systematically investigated as a function of the solution concentration and temperature. Experimental results indicated that the equilibrium adsorption data of the four polymeric adsorbents fitted well in the Freundlich isotherm. The adsorption capacity of multi-functional polymeric adsorbent NJ-99 was the highest, which might be attributed to the strong hydrogen-bonding interaction between the amino groups on the resin and the carboxyl group of aminobenzoic acid. The adsorption capacity of o-aminobenzoic acid onto any adsorbent was higher than p-aminobenzoic acid. Thermodynamic studies suggested the exothermic, spontaneous physical adsorption process. Adsorption kinetics results showed that the adsorption followed the pseudo-second-order kinetics model and the intraparticle mass transfer process was the rate-controlling step.

关键词： aromatic amphoteric compound aminobenzoic acid polymeric adsorbents adsorption thermodynamics kinetics

Dynamic Concept of Returns to Scales and Its Characteristics on Production Frontier in Intersection Form

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2011年第3期27卷 355-366页

作者： quan-ling Wei Hong Yan Institute of Operations Research and Mathematical Economics Renmin University of China Beijin 100872 China Department of Logistics The Hong Kong Polytechnic University Hung Hom Kowloon Hong Kong

This paper gives a dynamic concept and a new non-parametric method for evaluating returns to scale（RTS） of economic units with multiple inputs and *** is frequently noticed that when we increase the input of a decision making unit（DMU） with a certain status of RTS,different status of RTS is *** example,when we increase the input of a DMU with constant RTS under the traditional method,a decreasing RTS is often observed instead of the expected constant *** thus define the RTS of each DMU in both input expansion and contraction regions *** research starts from transferring the production possibility set into the intersection form,by giving the explicit linear inequality representation of production *** RTS structural characteristics of DMUs＇ on the production frontier are *** of RTS of those DMUs on the production frontier include increasing RTS,constant RTS,decreasing RTS,saturated RTS and evidence of *** and suficient conditions for RTS evaluation are *** definition and evaluation method given here provide more detailed economic characteristics of DMU for policy makers.

关键词： DEA production possibility set returns to scale

Hard magnetic properties of melt-spun nanocomposite Y_(16)Fe_(78)B_(6)ribbons

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2023年第2期42卷 602-605页

作者： Liang Sun Kuo-She Li Hong-Wei Li Dun-Bo Yu Yang Luo jin-ling jin Shuo Lu Ning-Tao quan GRIREM Advanced Materials Ltd General Research Institute for Nonferrous MetalsBeijing100088China

Melt-spun Y_(16)Fe_(78)B_(6)ribbons were prepared by the melt-spinning technique with pure elements Y,Fe and Fe-B alloy n *** ribbons are mainly composed of Y_(2)Fe_(14)B,YFe_(2)andα-Fe *** phase appears at the wheel velocity of>35 m·s^(-1).For the ribbons prepared at optimum wheel velocity and heat treatments,the coercivity,remanence and maximum energy product are239.5 kA·m^(-1),0.61 T and 32.7 kJ·m-3,*** an investigation of Henkel plots of ribbons,it is found that intergrain exchange coupling leads to the enhancement of *** coercivity mechanism of ribbons prepared at 35 m·s^(-1)is mainly controlled by inhomogeneous pinning of domain *** phase component and magnetic properties change with annealing temperature and *** optimum magnetic properties are obtained with the ribbon quenched at 35 m·s^(-1)and annealed at 700℃for10 min.

关键词： Melt spinning Permanent magnets Y-Fe-B alloys Magnetic hardening

Assessing ecological vulnerability in western China based on Time-Integrated NDVI data

在线全文

学校读者我要写书评

暂无评论

Journal of Arid Land 2016年第4期8卷 533-545页

作者： jin Jia WANG quan Joint Research Center of Drylands Xinjiang Institute of Ecology and GeographyChinese Academy of SciencesUrumqi 830011China University of Chinese Academy of Sciences Beijing 100049China Faculty of Agriculture Shizuoka UniversityShizuoka 422-8529Japan

Arid and semi-arid areas are the most vulnerable regions to climate change. Clear understanding of the effects of climate change on ecosystems in arid and semi-arid regions and the ecosystem vulnerability is important for ecosystem management under the background of climate change. In this study, we conducted a vulnerability assessment on various ecosystems from 1982 to 2013 in western China with large areas of arid and semi-arid lands based on the Time-Integrated Normalized Difference Vegetation Index （TINDVI） data and climate data. The results indicated that grasslands were the most vulnerable ecosystem to climate change in western China, especially for those in Tibetan Plateau. Croplands in oases were not vulnerable to climate change compared to rain-fed croplands in semi-arid regions （e.g. Gansu and Inner Mongolia）, which was attributed to the well-developed drip irrigation technology in oases. Desert and Gobi ecosystems were slightly vulnerable to climate change during the past several decades. The assessment results, as revealed in this study, can provide a reference for taking appropriate actions to protect the ecosystems in western China.

关键词： vulnerability sensitivity adaptability climate change Time-Integrated Normalized Difference VegetationIndex (TINDVI) western China

Construction of MoP/MoS_(2) Core-shell Structure Electrocatalyst for Boosting Hydrogen Evolution Reaction

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2024年第3期40卷 490-498页

作者： MENG Dan RAN Shunjiang GAO ling ZHANG Yue SAN Xiaoguang ZHANG Lei LI Ruixiang jin quan College of Chemical Engineering Shenyang University of Chemical TechnologyShenyang 110142P.R.China Key Laboratory of Automobile Materials(Ministry of Education) School of Materials Science and EngineeringJilin UniversityChangchun 130022P.R.China

Hydrogen energy stands out as one of the most promising alternative energy sources due to its cleanliness and *** water splitting offers a sustainable pathway for hydrogen ***,the kinetic rate of the hydrogen evolution reaction(HER)is sluggish,emphasizing the critical need for stable and highly active electrocatalysts to facilitate HER and enhance reaction *** metal-based catalysts have garnered attention for their favorable catalytic activity in electrochemical hydrogen evolution in alkaline *** this investigation,flower-like nanorods of MoS_(2) were directly synthesized in situ on a nickel foam substrate,followed by the formation of MoP/MoS_(2)-nickel foam(NF)heterostructures through high-temperature phosphating in a tube furnace *** findings reveal that MoP/MoS_(2)-NF-450 exhibits outstanding electrocatalytic performance in an alkaline milieu,demonstrating a low overpotential(90 mV)and remarkable durability at a current density of 10 mA/cm^(2).Comprehensive analysis indicates that the introduction of phosphorus(P)atoms enhances the synergistic effect with MoS_(2),while the distinctive flower-like nanorod structure of MoS_(2) exposes more active ***,the interface between the MoP/MoS_(2) heterostructure and NF facilitates electron transfer during hydrogen evolution,thereby enhancing electrocatalytic *** design and synthesis of such catalysts offer a valuable approach for the development of high-performance hydrogen evolution electrocatalysts.

关键词： MoP/MoS_(2) Core-shell structure Heterostructure Synergistic effect Hydrogen evolution reaction

3D analysis for pit evolution and pit-to-crack transition during corrosion fatigue

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 Zhejiang University-Science A(Applied Physics & Engineering) 2013年第4期14卷 292-299页

作者： Xiao-guang HUANG jin-quan XU Department of Engineering Mechanics China University of Petroleum Department of Engineering Mechanics Shanghai Jiao Tong University

This paper presents a deterministic model to predict the pit evolving morphology and crack initiation life of corrosion *** on the semi-ellipsoidal pit assumption,the thermodynamic potential including elastic energy,surface energy and electrochemical energy of the cyclically stressed solid with an evolving pit is established,from which specific parameters that control the pit evolution are introduced and their influence on the pit evolution are *** critical pit size for crack nucleation is obtained from stress intensity factor criterion and the crack nucleation life is evaluated by Faraday's ***,this paper presents a numerical example to verify the proposed model and investigate the influence of cyclic load on the corrosion fatigue crack nucleation *** corrosion pit appears approximately as a hemisphere in its early formation,and it gradually transits from semicircle to *** strain energy accelerates the morphology evolution of the pit,while the surface energy decelerates *** higher the stress amplitude is,the smaller the critical pit size is and the shorter the crack initiation life is.

关键词： Pit Evolving morphology Thermodynamic potential Critical pit size Crack nucleation

Oxidation behavior of artificial magnetite pellets

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2017年第6期24卷 603-610页

作者： Han-quan Zhang jin-tao Fu School of Resource and Civil Engineering Wuhan Institute of Technology Wuhan 430205 China Western Mining Company Xi’ning 810001 China

The oxidation behavior of artificial magnetite pellets was investigated through measurements of the oxidation degree and mineralogical analysis. The results show that artificial magnetite pellets are much easier to oxidize than natural magnetite. The oxidation is controlled through two different reaction mechanisms. The oxidation of artificial magnetite is dominated by internal diffusion, with an activation energy of 8.40 kJ/mol, at temperatures less than 800°C, whereas it is controlled by chemical reaction, with a reaction activation energy of 67.79 kJ/mol, at temperatures greater than 800°C. In addition, factors such as the oxygen volume fraction and the pellet diameter strongly influence the oxidation of artificial magnetite: a larger oxygen volume fraction and a smaller pellet diameter result in a much faster oxidation process.

关键词： artificial magnetite pellets oxidation reaction mechanisms

Experimental study of wind loads on gable roofs of low-rise buildings with overhangs

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2018年第3期12卷 300-317页

作者： Peng HUANG ling TAO Ming GU Yong quan i University Shanghai 200092China

Gable roofs with overhangs （eaves） are the common constructions of low-rise buildings on the southeastern coast of China, and they were vulnerable to typhoons from experience. The wind pressure distributions on gable roofs of low-rise buildings are investigated by a series of wind tunnel tests which consist of 99 test cases with various roof pitches, height-depth ratios and width-depth ratios. The block pressure coefficients and worst negative （block） pressure coefficients on different roof regions of low-rise buildings are proposed for the main structure and building envelope, respectively. The effects of roof pitch, height-depth ratio, and width-depth ratio on the pressure coefficients of each region are analyzed in detail. In addition, the pressure coefficients on the roofs for the main structure and building envelope are fitted according to roof pitch, height-depth ratio and width-depth ratio of the low-rise building. Meanwhile, the rationality of the fitting formulas is verified by comparing the fitting results with the codes of different countries. Lastly, the block pressure coefficients and worst negative pressure coefficients are recommended to guide the design of low-rise buildings in typhoon area and act as references for the future＇s modification of wind load codes.

关键词： low-rise building gable roof wind loads wind tunnel test block pressure coefficient load code

Semi-uniform Sub-additive Ergodic Theorems for Skew-product Quasi-flows

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

Acta Mathematicae Applicatae Sinica 2014年第2期30卷 359-366页

作者： jin-ling ZHOU Institute of Applied Mathematics Academy of Mathematics and Systems SciencesChinese Academy of Sciences

The aim of this paper is to extend the semi-uniform ergodic theorem and semi-uniform sub-additive ergodic theorem to skew-product quasi-flows. Furthermore, more strict inequalities about these two theorems are established. By making use of these results, it is feasible to get uniform estimation of the Lyapunov exponent of some special systems even under non-uniform hypotheses

关键词： semi-uniform sub-additive ergodic theorem skew-product quasi-flows