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Development of a group support system to support collaborative works in value management workshops

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journal of harbin Institute of Technology(New Series) 2004年第1期11卷 91-97页

作者： ChUNG j k h Dept. of Building and Real Estate Hong Kong Polytechnic University Kowloon Hong Kong China

Value Management (VM) is a rigorous and systematic approach to improve the value and optimise the overall cost of a facility. It identifies opportunities to remove unnecessary costs while assuring that quality, reliability, performance, and other critical factors will meet or exceed the customers’ expectations. It has been widely used in the construction industry in a number of countries. A recent survey, however, revealed several problems that hinder the wider use of this methodology in the industry. To overcome these problems, a feasibility study has been conducted to investigate whether or not a Group Support System (GSS) can support collaborative works in VM workshops. This paper introduces the development and structure of a prototype GSS which is designed to support the collaborative works of stakeholders in VM workshops. It begins with an introduction to the conceptual GSS framework and job plan, illustrating what GSS supports can be provided to VM workshops. This is followed by a detailed description of the GSS prototype system to demonstrate how these supports can be performed as an integrated computer system. The testing of the system is also discussed. The research findings provide strong evidence in supporting the notion of using GSS to improve VM implementation. The information support of GSS has been ranked to be the most useful GSS functions and most of the practitioners interviewed are highly interested in applying GSS to support VM workshops in the future.

关键词： group support system value management workshops construction

MODIFICATION OF SODIUM SALT OF PARTIALLY CARBOXYMEThYLATED TAMARIND kERNEL POWDER ThROUGh GRAFTING WITh ACRYLONITRILE: SYNThESIS, ChARACTERIZATION AND SWELLING BEhAVIOR

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Chinese journal of Polymer Science 2013年第12期31卷 1670-1684页

作者： j.h.Trivedi j.R.jivani k.h.Patel h.C.Trivedi P.G.Dept.of Chemistry Sardar Patel UniversityVallabh Vidyanagar Amneal Phamaceuticals

A graft copolymer of polyacrylonitrile （PAN） with sodium salt of partially carboxymethylated tamarind kernel powder （Na-PCMTkP, DS ^-= 0.15） was synthesized by using ceric ammonium nitrate （CAN） as a redox initiator in an aqueous medium. The optimum reaction conditions for affording maximum percentage of grafting were established by successively varying reaction conditions such as concentrations of nitric acid, CAN, monomer （AN） as well as reaction time, temperature and amount of substrate. The influence of these reaction conditions on the grafting yields was discussed. The kinetic scheme of free radical graft copolymerization was proposed and the experimental results were found to agree very well with the proposed kinetic scheme. The graft copolymer （Na-PCMTkP-g-PAN, percentage of grafting G = 413.76% and percentage of grafting efficiency GE = 96.48%） sample synthesized under the established optimized reaction conditions was hydrolyzed by 0.7 mol-L l NaOh solution at 90-95 ℃ to yield the superabsorbent hydrogel, h-Na-PCMTkP-g-PAN. The swelling behavior of the hydrogel was studied by carrying out its absorbency measurements in low conductivity water, 0.15 mol·L^-1 salt （NaCl, CaCl2 and AlCl3） solutions and simulated urine （SU） solution at different timings. FTIR, TGA and SEM techniques were used to characterize the products.

关键词： Sodium salt of partially carboxymethylated tamarind kernel powder Acrylonitrile Graft copolymerization Superabsorbent hydrogels Swelling behavior.

ThE -PROBLEM FOR hOLOMORPhIC (0,2)-FORMS ON PSEUDOCONVEX DOMAINS IN SEPARABLE hILBERT SPACES AND D.F.N. SPACES

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Chinese Annals of Mathematics,Series B 2002年第1期23卷 67-74页

作者： j.LEE k.h.ShON DepartmentofMathematicsEducation AndongNationalUniversityAndong760-749Korea DepartmentofMathematics PusanNationalUniversityPusan609-735Korea

This paper shows that the 8-problem for holomorphic (0, 2)-forms on hubert spaces is solv-able on pseudoconvex open subsets. By using this result, the authors investigate the existence of the solution of the -equation... 详细信息

关键词： -prob1em Pseudoconvex domain Nuclear operator D.F.N. space

Order Environments of Topological Spaces

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Acta Mathematica Sinica,English Series 2004年第5期20卷 943-948页

作者： j.h.LIANG k.kEIMEL Department of Mathematics Sichuan Univ.Chengdu 610064P.R.China Department of Mathematics Darmstadt Univ.Germany

In this paper it is proved that a space may be realized as the set of the maximal elementsin a continuous poset if and only if it is Tychonoff.

关键词： Domain environment Weakly complete Tychonoff space

Achieving exceptional wear resistance in a crack-free high-carbon tool steel fabricated by laser powder bed fusion without pre-heating

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journal of Materials Science & Technology 2023年第25期156卷 1-19页

作者： konrad kosiba Daniel Wolf Matthias Bönisch kai Neufeld Ruben hühne Tobias Gustmann jozef Bednarčík hongyu Chen Xiaoliang han Volker hoffmann Lukas Beyer Uta kühn Sergio Scudino Lars Giebeler julia k.hufenbach Leibniz Institute for Solid State and Materials Research (IFW) Dresden E.V. Helmholtzstr. 20Dresden 01069Germany Department of Materials Engineering KU LeuvenKasteelpark Arenberg 44bus 2450Leuven 3001Belgium Department of Condensed Matter Physics Institute of PhysicsP.J. Safarik University in KosicePark Angelinum 9Kosice 04154Slovakia Institute of Experimental Physics Slovak Academy of ScienceWatsonova 47Kosice 040 01Slovakia key Laboratory of Impact and Safety Engineering of Ministry of Education of China Ningbo UniversityNingbo 315211China TU Bergakademie Freiberg Institute of Materials ScienceGustav-Zeuner-Str. 5Freiberg 09599Germany

Laser powder bed fusion(LPBF)for the fabrication of dense components used for tooling applications,is highly *** stresses,which evolve in the additively manufactured part,are inherent to LPBF *** additional stress contribution in high-carbon steels arises from the austenite-to-martensite phase transformation,which may eventually lead to cracking or even *** an alternative to pre-heating the base plate,which is not striven by industry,lowering the martensite content which forms in the part,is essential for the fabrication of dense parts by LPBF of high-carbon tool steels which are then adapted to *** this study,a successful strategy demonstrates the processing of the Fe85Cr4Mo1V1W8C1(wt%)high-carbon steel by LPBF into dense parts(99.8%).The hierarchical microstructure consists of austenitic and martensitic grains separated by elemental segregations in which nanoscopic carbide particles form a network.A high density of microsegregation was observed at the molten pool boundary ultimately forming a *** LPBF-fabricated steel shows a yield strength,ultimate compressive stress,and total strain of 1210 MPa,3556 MPa,and 27.4%,*** mechanical and wear performance is rated against the industrially employed and highly wear-resistant 1.2379 tool steel taken as the *** its lower macro-hardness,the LPBF steel(58.6 hRC,0.0061 mm^(3) Nm^(-1))shows a higher wear resistance than the reference steel(62.6 hRC,0.0078 mm^(3) Nm^(-1)).This behavior results from the wear-induced formation of martensite in a microscale thick layer directly at the worn surface,as it was proven via high-energy X-ray diffraction mapping.

关键词： Additive manufacturing Laser powder bed fusion Steel Wear TRIP

Effect of Solute Contents of Al-Ni-Sr Alloy on Glass Forming Ability and Thermal Stability

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journal of Rare Earths 2004年第z2期22卷 73-77页

作者： Taek Soo kim j k Lee h j kim j C Bae Advanced Materials R&D Center Korea Institute of Industrial Technology994-32 Dongchun-dongYeonsu-kuIncheon 406-130Korea Advanced Materials R&D CenterKorea Institute of Industrial Technology994-32 Dongchun-dongYeonsu-kuIncheon 406-130Korea Advanced Materials R&D CenterKorea Institute of Industrial Technology994-32 Dongchun-dongYeonsu-kuIncheon 406-130Korea Advanced Materials R&D CenterKorea Institute of Industrial Technology994-32 Dongchun-dongYeonsu-kuIncheon 406-130Korea

Glass forming ability (GFA) and structural characterization of a new amorphous Al-Ni-Sr alloy melt spun were investigated on the theory of the factors for the glass formation. The GFA was varied with the ratio of Ni to Sr in detail and successful amorphous phase dispersed with 2 ～ 5 nm precipitates was prepared from Al-Ni5-Sr3. Thermal stability and crystallization behavior of the amorphous phase were determined by continuous and isothermal heating technique on DCS, resulting that the crystallization occurs by the growth of fcc Al nanocrystals on the preexistent nuclei.

关键词： glass formation crystallization Al base amorphous alloys rapid solidification

CONVERGENCE OF ThE LAX-FRIEDRIChS SChEME AND STABILITY FOR CONSERVATION LAWS WITh A DISCONTINUOUS SPACE-TIME DEPENDENT FLUX

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Chinese Annals of Mathematics,Series B 2004年第3期25卷 287-318页

作者： k.h.kARLSEN j.D.TOWERS DepartmentofMathematics UniversityofBergenJohs.Brunsgt.12N-5008BergenNorway MiraCostaCollege 3333ManchesterAvenueCardiff-by-the-SeaCA92007-1516USA

The authors give the first convergence proof for the Lax-Friedrichs finite differencescheme for non-convex genuinely nonlinear scalar conservation laws of the formu_t + f(k(x, t), u)_x = 0,where the coefficient k(x, t) is allowed to be discontinuous along curves in the (x, t)plane. In contrast to most of the existing literature on problems with discontinuouscoefficients, here the convergence proof is not based on the singular mapping approach,but rather on the div-curl lemma (but not the Young measure) and a Lax type en-tropy estimate that is robust with respect to the regularity of k(x, t). Following [14],the authors propose a definition of entropy solution that extends the classical kruzkovdefinition to the situation where k(x, t) is piecewise Lipschitz continuous in the (x, t)plane, and prove the stability (uniqueness) of such entropy solutions, provided that theflux function satisfies a so-called crossng condition, and that strong traces of the solu-tion exist along the curves where k(x, t) is discontinuous. It is shown that a convergentsubsequence of approximations produced by the Lax-Friedrichs scheme converges tosuch an entropy solution, implying that the entire computed sequence converges.

关键词： Conservation law Discontinuous coefficient Nonconvex flux LaxFriedrichs difference scheme Convergence Compensated compactness Entropy condition Uniqueness

A DUCTILE FRACTURE CRITERION BASED ON ThREEDIMENSIONAL VOID MODEL

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Acta Metallurgica Sinica(English Letters) 2008年第3期21卷 227-234页

作者： j.k. huang X.h. Dong National Die ＆ Mould CAD Engineering Research Center Shanghai Jiaotong University Shanghai 200030China

A fracture criterion derived from a microscopic point of view is proposed and has proved to be effective in the analysis of uniaxial tension. On the one hand, a method of predicting a ductile fracture is proposed using a three-dimensional void model and the assumption of velocity discontinuity. The relationship between the void volume fraction and the critical strain to fracture, calculated with the help of the new model, shows the same tendency as that obtained from the modified Thomason model. On the other hand, the mechanical and metallographic analyses of the uniaxial tension experiment are performed using four kinds of carbon steel. The relationship between the void volume fraction and the critical strain to fracture, calculated from the new model, agrees better with the result obtained from the experiment, rather than that calculated by the modified Thomason model, which confirms the validity of the ductile fracture criterion based on the three-dimensional void model.

关键词： Fracture criterion Uniaxial tension Velocity discontinuity Mechanical and metallographic analyses

Preparation of Pure Copper Powder from Acidic Copper Chloride Waste Etchant

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journal of Materials Science & Technology 2008年第1期24卷 141-142页

作者： h.S.hong M.S.kong j.k.Ghu j.k.Lee h.G.Suk Plant Engineering Center.Institute for Advanced Engineering Yongin 449-863 Korea Dept. of Advanced Mater. Eng. Korea Polytechnic University Shihung 429-793 Korea Nano-surface Treat. Tech. Team Korea Inst. of Industrial Technology Incheon 463-130 Korea Dept. of Mater. and Met. Eng. Kangwon National University Samcheok 245-711 Korea

The method for the recycling of copper from copper chloride solution was developed. This process consists of extraction of copper, purification and particle size reduction. In the first step, reductive metal scraps were added to acidic copper chloride waste enchants produced in the PCB industry to obtain copper powder. Composition analysis showed that this powder contained impurities such as Fe, Ni, and water. So, drying and purification were carried out by using microwave and a centrifugal separator. Thereby the copper powder had a purity of higher than 99% and spherical form in morphology. The copper powder size was decreased by ball milling.

关键词： Copper chloride liquid waste Printed circuit board (PCB), Liquid waste highpurity copper powder