检索结果-南通市图书馆

Journal of Environmental Sciences 2012年第9期24卷 1559-1568页

作者： X.J.lee l.y.lee l.P.y.Foo D.G.Hassell Department of Chemical and Environmental Engineering University of Nottingham Malaysia CampusJalan Broga43500 SemenyihSelangor Darul EhsanMalaysia.

The present work covers the preparation of carbon-based nanosorbents by ethylene decomposition on stainless steel mesh without the use of external catalyst for the treatment of water containing nickel ions （Ni2＋）. The reaction temperature was varied from 650 to 850℃, while reaction time and ethylene to nitrogen flow ratio were maintained at 30 rain and 1：1 cma/min, respectively. Results show that nanosorbents synthesised at a reaction temperature of 650℃ had the smallest average diameter （75 nm）, largest BET surface area （68.95 m2/g） and least amount of impurity （0.98 wt.% Fe）. A series of batch sorption tests were performed to evaluate the effects of initial pH, initial metal concentration and contact time on Ni2~ removal by the nanosorbents. The equilibrium data fitted well to Freundlich isotherm. The kinetic data were best correlated to a pseudo second-order model indicating that the process was of chemisorption type. Further analysis by the Boyd kinetic model revealed that boundary layer diffusion was the controlling step. This primary study suggests that the prepared material with Freundiich constants compared well with those in the literature, is a promising sorbent for the sequestration of Ni2＋ in aqueous solutions.

关键词： adsorption nanosorbent nickel ions isotherms kinetics

Effect of Thermal Refining on Mechanical Properties of Annealed SAE 4130 by Multilayer GTAW

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2012年第7期19卷 71-78页

作者： I K lee C l Chung y T lee y T Chien Department of Materials Science and Engineering Da-Yeh University

During the first welding process in manufacturing a precise seam container, the steel material must first undergo a full annealing treatment. Multilayer welding operations are conducted and then applied with refining treatment to obtain the goal by hardening. The influence of thermal refining on mechanical properties of annealed SAE 4130 by multilayer GTAW （gas tungsten arc welding） was discussed. The AW （annealing＋welding） and AWST （annealing＋welding＋solution＋tempering） occurred with a minimum hardness value at GGHAZ （grain growth heat affected zone） due to coarse grain growth~ the hardness occurred with sudden drops between the multilayer welding, but was still larger than the minimum value at HAZ （heat affected zone）. The welded joint efficiency of the AWST was 89.9%, with the elongation reduced to 77.2% of AST （annealing＋solution＋tempering）. The cross section of the tensile samples both appeared with a uniform dimple-shaped structure, and however the necking for AST was greater than that for AWST. The impact value for AWST was 166.5% of AST. Moreover, from microstructure observations, it was found that AWST had a greater tendency to ductile failure than AST. These results can be inferred., the process of steady pressure and the initial position of the precision tube breakage HAZ. However, when stress occurs instantly, HAZ can absorb more energy, therefore the initial damage does not occur.

关键词： thermal refining SAE 4130 multilayer welding GTAW

AN INVESTIGATION INTO TENANT ORGANIZATIONS' WIllINGNESS-TO-PAy FOR THE INTANGIBlE VAlUE-ADDED BENEFITS OF SUSTAINABlE BUIlDINGS:CASE STUDy IN SINGAPORE

在线全文

学校读者我要写书评

暂无评论

Journal of Green Building 2015年第3期10卷 191-213页

作者： Irene y.l.lee Huiyu Chen Robert l.K.Tiong Building Research Institute Housing&Development Board480 Lorong 6 Toa Payoh Singapore 310480 School of Civil and Environmental Engineering Nanyang Technological UniversityBlock N1Nanyang AvenueSingapore 639789

This research aims to understand the demand for sustainable buildings by inves-tigating the tenant organizations’willingness-to-pay(WTP)behavior towards the value-added benefits(VABs).Tenant organizations refer to tenants operating in office buildings on tenancy *** groups of factors of tenant organi-zations’WTP for the VABs are identified:(1)Organization Characteristics,(2)Current Premises,(3)Building Characteristics,(4)Satisfaction of the VABs Expe-rienced,(5)Perception,and(6)Knowledge of Sustainability Issues,Building Sus-tainability Rating Systems and Building Impacts.A survey was conducted on the tenant organizations operating in office buildings located in the city area of *** hypothesized relationship between the tenant organizations’WTP for the VABs and its factors were tested using a series of statistical techniques on the data collected from the *** is found that older tenant organizations tend to have lower WTP for the VABs of improved health and comfort of their ***,tenant organizations also have demand for sustainable buildings mainly due to the positive organizational image that sustainable buildings help to *** addition,it is found that the current building sustainability rating systems are inadequate for communicating the sustainability benefits to building occupants and for achieving building ***,the investigation reveals that the use of sustainable technologies is not as important as how the building is being managed during its operational stage for ensuring building sustainability *** findings from this study are useful for channeling the sustainability efforts of the building industry to more effective areas.

关键词： Sustainable Buildings Intangible Value-added Benefits Willingness-to-pay Tenant Organizations Office Buildings Indoor Environment Quality

Purge and trap method to determine alpha factors of VOC liquid-phase mass transfer coefficients

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

Chinese Science Bulletin 2000年第S1期45卷 76-79页

作者： S.C.lee l.y.Chan C.y.Chan Department of Civil & Structural Engineering The Hong Kong Polytechnic UniversityHong KongChina Correspondence should be addressed to Wang XinmingDepartment of Civil & Structural EngineeringThe Hong Kong Polytechnic UniversityHong KongChina Correspondence should be addressed to Wang XinmingDepartment of Civil & Structural EngineeringThe Hong Kong Polytechnic UniversityHong KongChina Correspondence should be addressed to Wang Xinming

A theoretical approach and laboratory practice of determining the alpha factors of volatile organic compound (VOC) liquid-phase mass transfer coefficients are present in this study. Using Purge & Trap Concentrator, VOC spiked water samples are purged by high-purity nitrogen in the laboratory, the VOC liquid-phase mass transfer rate constants under the laboratory conditions are then obtained by observing the variation of VOCs purged out of the water with the purge time. The alpha factors of VOC liquid-phase mass transfer coefficients are calculated as the ratios of the liquid-phase mass transfer rate constants in real water samples to their counterparts in pure water under the same experimental conditions. This direct and fast approach is easy to control in the laboratory, and would benefit mutual comparison among researchers, so might be useful for the study of VOC mass transfer across the liquid-gas interface.

关键词： mass transfer coefficient purge and trap volatile organic compounds alpha factor.

Effect of Aging Treatment on Microstructural and Mechanical Characteristics of PEO Coatings on Mg-Al Alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2008年第1期24卷 37-40页

作者： y.l.Kim Department of Materials Engineering Korea Aerospace University Gyeonggi-do412-791Korea

Cast Mg-6 wt pct Al alloy solution-treated at 683 K for 16 h and aged at 498 K was coated by plasma electrolytic oxidation （PEO） *** Mg-6 wt pct Al alloy aged for 16 h exhibited the highest microhardness and wear *** PEO coating,however,the microhardness and wear resistance of coatings on Mg- 6 wt pct Al alloy showed a tendency to decrease with increasing aging time,which was in aggrement with the change of thickness with aging *** addition,the coatings on solution-treated Mg-6 wt pct Al alloy had better microhardness and wear resistance than those on aged Mg-6 wt pct Al ***,it can be understood that the aging treatment has a deleterious influence on the mechanical properties of coatings on Mg-6 wt pct Al alloy.

关键词： Cast Mg-6 wt pct Al Aging treatment Plasma electrolytic oxidation Thickness Microhardness Wear resistance

Active elastic metamaterials for subwavelength wave propagation control

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2015年第3期31卷 349-363页

作者： y.y.Chen G.l.Huang Department of Mechanical and Aerospace Engineering University of Missouri

Recent research activities in elastic metamaterials demonstrate a significant potential for subwavelength wave propagation control owing to their interior locally resonant mechanism. The growing technological developments in electro/magnetomechanical couplings of smart materials have introduced a controlling degree of freedom for passive elastic metamaterials. Active elastic metamaterials could allow for a fine control of material physical behavior and thereby induce new functional properties that cannot be produced by passive approaches. In this paper, two types of active elastic metamaterials with shunted piezoelectric materials and electrorheological elastomers are proposed. Theoretical analyses and numerical validations of the active elastic metamaterials with detailed microstructures are pre- sented for designing adaptive applications in band gap structures and extraordinary waveguides. The active elastic metamaterial could provide a new design methodology for adaptive wave filters, high signal-to-noise sensors, and structural health monitoring applications.

关键词： Active elastic metamaterials Subwavelengthwave control Adaptive metastructures Smart materials

Comparative Study on Shearing Edge Quality Influence of the Change of Tool Geometry in Fine-Blanking for Non-homogeneous Materials

在线全文

学校读者我要写书评

暂无评论

厦门大学学报（自然科学版） 2002年第S1期41卷 117-118页

作者： y C leung l C Chan T C lee Department of Industrial and Systems Engineering the Hong Kong Polytechnic UniversityDepartment of Industrial and Systems Engineering the Hong Kong Polytechnic UniversityDepartment of Industrial and Systems Engineering the Hong Kong Polytechnic University Hong Kong ChinaHong Kong ChinaHong Kong China

Excellent quality of shearing edge implies that a s mo oth cutting edge without tearing will be observed on the whole edge surface. Thi s is one of the most significant features of the Fine-blanking process. To achi eve such a superb blanking edge quality in fine-blanking, there actually involv es quite a large number of factors, such as blanking speed, processing material, product shape, lubrication and tool geometry, to be considered simultaneously d uring the operation. Nevertheless, the thorough investigations on different effe cts of those critical factors for different kinds of popular and applicable mate rial are rare and limited. Thus, the objective of this paper is mainly focused o n the study of the quality influence of tool geometry change in fine-blanking f or non-homogeneous materials. However, the most obvious change of the tool geo metry during the operation will be the essential variation of the nose radius of the punch. This is because the nose radius usually seriously deteriorates with the increasing service period in mass production which eventually causes the ent irely lose of the specific features of the fine-blanking process. Therefore, a tailor-made experimental study was carried out to investigate the relationship between the punch nose radius and the shearing edge quality, such as blanked edg e finish, burr height and die-roll height, during fine-blanking for different types of material. Five punches with each specified nose radius (Rp), 0.00 mm, 0.25 mm, 0.50 mm, 0.75 mm and 1.00 mm, and four kinds of blanking material ( Mil d steel SS400, Stainless steel AISI316l, Copper alloy UNSC16200 and Aluminium al loy AA6063 ) were employed throughout the study. Subsequently, features of the s heared edge surfaces and data of each experiment were observed and captured for further analysis in this research. Consequently, findings show that an increase of punch nose radius would produce a higher percentage of fracture of blanked ed ge and increase the

关键词： fine-blanking tool geometry shearing edge qual ity

Microstructure and mechanical behavior of laser aided additive manufactured low carbon interstitial Fe_(49.5)Mn_(30)Co_(10)Cr_(10)C_(0.5)multicomponent alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2021年第18期77卷 38-46页

作者： y.Chew Z.G.Zhu F.Weng S.B.Gao F.l.Ng B.y lee G.J.Bi Singapore Institute of Manufacturing Technology 73 Nanyang Drive637662Singapore School of Mechanical Aerospace Engineering Nanyang Technological University50 N any ang Avenue639798Singapore

laser aided additive manufacturing(lAAM)was used to fabricate bulk Fe_(49.5)Mn_(30)Co_(10)Cr_(10)C_(0.5)interstitial multicomponent alloy using pre-alloyed *** room temperature yield strength(σ_y),ultimate tensile strength(σ_(UTS))and elongation(ε_(UTS))were 645 MPa,917 MPa and 27.0%*** asbuilt sample consisted of equiaxed and dendritic cellular structures formed by elemental *** cellular structures together with oxide particle inclusions were deemed to strengthen the *** other contributing components include dislocation strengthening,friction stress and grain boundary *** highε_(UTS)was attributed to dislocation motion and activation of both twinning and transformation-induced plasticity(TWIP and TRIP).Tensile tests performed at-40℃and-130℃demonstrated superior tensile strength of 1041 MPa and 1267 MPa ***,almost no twinning was observed in the fractured sample tested at-40℃and-130℃.Instead,higher fraction of strain-induced hexagonal close-packed(HCP)εphase transformation of 21.2%were observed for fractured sample tested at-40℃,compared with 6.3%in fractured room temperature sample.

关键词： Multicomponent alloys laser aided additive manufacturing Additive manufacturing Microstructure Mechanical property

Exact solution of the one-dimensional Klein-Gordon equation with scalar and vector linear potentials in the presence of a minimal length

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2010年第2期19卷 43-47页

作者： y Chargui l Chetouani A Trabelsi Unit de Recherche de Physique Nuclaire et des Hautes Energies Facult des Sciences de Tunis Dpartement de Physique Thorique Institut de PhysiqueUniversit de ConstantineRoute Ain El BeyConstantineAlgeria Centre National des Sciences et Technologies Nuclaires Technopole de Sidi-Thabet 2020Tunisia

Using the momentum space representation, we solve the Klein--Gordon equation in one spatial dimension for the case of mixed scalar and vector linear potentials in the context of deformed quantum mechanics characterized by a finite minimal uncertainty in position. The expressions of bound state energies and the associated wave functions are exactly obtained.

关键词： Klein--Gordon equation linear potential minimal length exact solution

Mathematical modelling of axonal microtubule bundles under dynamic torsion

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2018年第6期39卷 829-844页

作者： J.y.WU Hong yUAN l.y.lI MOE Key laboratory of Disaster Forecast and Control in Engineering Institute of Applied MechanicsJinan University School of Engineering University of Plymouth

Owing to its viscoelastic nature, axon exhibits a stress rate-dependent me- chanical behavior. An extended tension-shear chain model with Kelvin-Voigt viscoelas- ticity is developed to illustrate the micromechanical behavior of the axon under dynamic torsional conditions. Theoretical closed-form expressions are derived to predict the de- formation, stress transfer, and failure mechanism between microtubule （MT） and tau protein while the axon is sheared dynamically. The results obtained from the present an- alytical solutions demonstrate how the MT-tau interface length, spacing between the tau proteins, and loading rate affect the mechanical properties of axon. Moreover, it is found that the MTs are more prone to rupture due to the contributions from the viscoelastic effects. Under the torsional force, the MTs are so long that the stress concentrates at the loaded end where axonal MTs will break. This MT-tau protein dynamics model can help to understand the underlying pathology and molecular mechanisms of axonal injury. Additionally, the emphasis of this paper is on the micromechanical behavior of axon, whereas this theoretical model can be equally applicable to other soft or hard tissues, owning the similar fibrous structure.

关键词： torsion biocomposite diffuse axonal injury (DAI) Kelvin-Voigt viscoelas-tic model dynamic response tension-shear chain model