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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

Influence of Carrier Gas on Analysis of MgO Powders by Laser Ablation Inductively Coupled Plasma Mass Spectrometry

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journal of Materials Science & Technology 2009年第3期25卷 333-335页

作者： j.S. lee Y.S. lee C.j. Park h.S. lee D.S. lee Department of Chemistry Yonsei University Material Analysis Team Korea Testing Laboratory Korea Research Institute of Standards and Science School of Material Science and Engineering Pusan National Univirsity

Laser ablation inductively coupled plasma mass spectrometry （LA-ICP-MS） has been widely adopted for the direct multi-elemental analysis with high sensitivity. Especially analysis of fine ceramics by LA-ICP-MS without time-consuming sample decomposition process has been one of the most expecting application field. Small additive elements in MgO powders were analyzed by LA-ICP-MS. For precise and accurate analysis influence of carrier gas （Ar or he） was presented by the signal intensities of ICP-MS, relative standard deviation of signal intensities and ablated particle size distribution. Ablated particles were collected and analyzed by scanning electron microscopy （SEM） to investigate the particle size distribution, and the ablated sample surface was examined by camscope. In he gas atmosphere, the signal was more stable than in Ar gas atmosphere. The signal intensity was higher in Ar than in he. Examination of ablated particles and sample surface reveals that more particles were generated in Ar atmosphere and the distribution of particle size was larger.

关键词： Laser ablation MgO powders Carrier gas ICP-MS

Fabrication of SAW Sensor for Detecting Chemical Agent

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稀有金属材料与工程 2006年第A03期35卷 433-435页

作者： j.h.lee B S joo j S huh D D lee School of Electronic & Electrical Engineering Kyungpook National UniversityKorea Dept.of Materials Science and Metallurgy Kyungpook National UniversityKorea

SAW sensors using five different types of polymer to detect of chemical agents(DMMP,Ch_3CN,Ch_2Cl_2,DCP) have been fabricated and its gas response characteristics were extensively *** polymers used as the sensing material are polyisobutylene(PIB),polyepichlorohydrin(PECh),polydimethylsiloxane(PDMS),polyisoprene(PIP)and polybutadiene(PBD).Their thin films were coated on quartz substrate by spin coating *** types of simulants gases,dimethylmethylphosphonate(DMMP),acetonitrile(Ch_3CN)and dichloromethane(Ch_2Cl_2),dichloropentane(DCP)were used as target gases,instead of the real nerve,blood,choking and vesicant *** spin coating of PIB and PECh,the substrates were heated to 65℃with N_2 flow for 1 h to remove the cyclohexane and ethylacetate which was used as solvent. PDMS was heated to 75℃with N_2 flow for 2 h to remove the ethylacetate which was used as *** and PIP on the substrate were heated to 60℃with N_2 flow for 1 h to remove the benzen which was used as *** sensing characteristics of the SAW sensors were measured by using E-5061A network analyzer.

关键词： SAW DMMP Ch3CN Ch2Cl2 DCP polymer film

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

Numerical Experiment on Two-Dimensional Line Thermal

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China Ocean Engineering 2002年第4期17卷 453-467页

作者： j.h.W.lee 陈国谦 Department of Civil Engineering University of Hong KongHongkongChina National Laboratory for Turbulence Peking UniversityBeijing 100871China

The time evolution of a two-dimensional line thermal-a turbulent flow produced by an initial element with significant buoyancy released in a large water body, is numerically studied with the two-equation k - epsilon model for turbulence closure. The numerical results show that the thermal is characterized by a vortex pair flow and a kidney shaped concentration structure with double peak maxima; the computed flow details and scalar mixing characteristics can be described by self-similar relations beyond a dimensionless time around 10. There are two regions in the flow field of a line thermal: a mixing region where the concentration of tracer fluid is high and the flow is turbulent and rotational with a pair of vortex eyes, and an ambient region where the concentration is zero and the flow is potential and well-described by a model of doublet with strength very close to those given by early experimental and analytical studies. The added virtual mass coefficient of the thermal motion is found to be approximately 1. The aspect ratio for the kidney-shaped sectional thermal is found to be around 1.45 for the self-similar phase. The predicted thermal spreading and mixing rate compares well with experimental data.

关键词： thermals and puffs turbulence modeling plumes and jets environmental fluid mechanics vortex flow added virtual mass mixing and transport

Effect of coating material and lubricant on forming force and surface defects in wire drawing process

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Transactions of Nonferrous Metals Society of China 2011年第A01期21卷 104-110页

作者： S.M.BYON S.j.lee D.W.lee Y.h.lee Y.lee Department of Mechanical Engineering Dong-A University Department of Mechanical Engineering Chung-Ang University Wire Rod Research Group POSCO Technical Research Laboratories

A pilot wire drawing machine as well as wire end-pointing roller was developed. Using these machines, a wire drawing test for four different coating materials and two different lubricants was performed as the reduction ratio increased from 10% to 30%. Materials used for a substrate in this study are plain carbon steel （AIS11045） and ultra low carbon bainite steel. To compute the friction coefficient between the coating layer of wire and the surface of die lbr a specific lubricant, a series of finite element analyses were carried out. SEM observations were also conducted to investigate the surface defects of wire deformed. Results show that the behavior of drawing force varies with the lubricant-type at the initial stage of drawing. The powder-typed lubricant with a large particle causes the retardation of lull lubrication on the entire contact surface and the local delamination of coating layer on the wire surface. As the flow stress of a substrate increases, the delamination becomes severe.

关键词： coating lubricant wire drawing delamination

Temperature and Thermal Stress Distribution for Metal Mold in Squeeze Casting Process

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journal of Materials Science & Technology 2008年第3期24卷 347-350页

作者： C.h.lee S.h.lee Institute of Technology and Science Chung-Ang University

In the squeeze casting process, loaded high pressure （over approximately 200 MPa） and high temperature influence the thermo-mechanical behavior and performance of the used metal mold. Therefore, to safely maintain the metal molds, the thermo-mechanical characteristics （temperature and thermal stress） of metal mold in the squeeze casting must be investigated. In this paper, temperature and thermal stress distribution of steel mold in squeeze casting process were investigated by using a three-dimensional non-steady heat conduction analysis and a three-dimensional thermal elastic-plastic analysis considering temperature-dependent thermophysical and mechanical properties of the steel mold.

关键词： Squeeze casting Steel mold Thermal stress Thermo-Mechanical analysis

Fault detection method with PCA and LDA and its application to induction motor

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journal of Central South University 2010年第6期17卷 1238-1242页

作者： jUNG D Y lee S M 王洪梅 KIM j.h.lee S h Daeho Tech Company Limited Department of Electronics Engineering Inha University School of Mechatronics Changwon National University

A feature extraction and fusion algorithm was constructed by combining principal component analysis(PCA) and linear discriminant analysis(LDA) to detect a fault state of the induction *** yielding a feature vector with PCA and LDA from current signal that was measured by an experiment,the reference data were used to produce matching *** a diagnostic step,two matching values that were obtained by PCA and LDA,respectively,were combined by probability model,and a faulted signal was finally *** the proposed diagnosis algorithm brings only merits of PCA and LDA into relief,it shows excellent performance under the noisy *** simulation was executed under various noisy conditions in order to demonstrate the suitability of the proposed algorithm and showed more excellent performance than the case just using conventional PCA or LDA.

关键词： principal component analysis (PCA) linear discriminant analysis (LDA) induction motor fault diagnosis fusionalgorithm

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journal of Central South University 2009年第5期16卷 789-793页

作者： KIM j.h.lee S h 王洪梅 School of Mechatronics Changwon National University 9 Sarim-dong Changwon Gyeongnam 641-773 Korea

Fault detection technique is introduced with similarity measure. The characteristics of conventional similarity measure based on fuzzy number are discussed. With the help of distance measure, similarity measure is constructed explicitly. The designed distance-based similarity measure is applicable to general fuzzy membership functions including non-convex fuzzy membership function, whereas fuzzy number-based similarity measure has limitation to calculate the similarity of general fuzzy membership functions. The applicability of the proposed similarity measure to general fuzzy membership structures is proven by identifying the definition. To decide fault detection of flight system, the experimental data （pitching moment coefficients and lift coefficients） are transformed into fuzzy membership functions. Distance-based similarity measure is applied to the obtained fuzzy membership functions, and similarity computation and analysis are obtained with the fault and normal operation coefficients.

关键词： similarity measure fuzzy number, distance non-convex membership function