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journal of Materials Science & Technology 2009年第5期25卷 649-654页

作者： K.Alvarez H.y.kim S.Miyazaki Graduate School University of TsukubaIbaraki 305-8573Japan Institute of Materials Science University of TsukubaTsukubaIbaraki 305-8573Japan

The microstructural features, shape memory behavior and mechanical properties of Ni-Mn based alloys were investigated by differential scanning calorimetry （DSC）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM） and thermal cycling test under various stresses. The transformation temperatures shifted toward lower temperatures when adding a third element into the Ni-Mn system. The addition of 10 at. pct Fe increased considerably the mechanical properties exhibiting still high transformation temperatures. However, it was found that in NiMn40Fe10 alloy the martensitic transformation is not thermoelastic in nature. The mechanism of this transformation and the crystallography of Ni-Mn（50-x）-Fex （x=5, 7, 10, 20 at. pct） alloys are presented.

关键词： Ni-Mn based alloys Martensitic transformation temperature L10 phase

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

Experimental and Numerical Investigation on Impact Performance of Carbon Reinforced Aluminum Laminates

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journal of Materials Science & Technology 2010年第4期26卷 327-332页

作者： S.H. Song y.S. Byun T.W. Ku W.j. Song j. kim B.S. Kang National Core Research Center Pusan National University Busan 609-735 Korea Dept. of Aerospace Engineering Pusan National University Busan 609-735 Korea Industrial Liaison Innovation Cluster Pusan National University Busan 609-735 Korea

It is known that fiber metal laminates （FML） as one of hybrid materials with thin metal sheets and fiber/epoxy layers have the characteristics of the excellent damage tolerance, fatigue and impact properties with a relatively low density. Therefore, the mechanical components using FML can contribute the enhanced safety level of the sound construction toward the whole body. In this study, the impact performance of carbon reinforced aluminum laminates （CARAL） is investigated by experiments and numerical simulations. Drop weight tests are carried out with the weight of 4.7 kg at the speed of 1 and 2 m/s, respectively. Dynamic non-linear transient analyses are also accomplished using a finite element analysis software, ABAQUS. The experiment results and numerical results are compared with impact load-time histories. Also, energy-time histories are applied to investigate the impact performance of CARAL.

关键词： Fiber metal laminates (FML) Carbon reinforced aluminum laminates (CARAL) Numerical simulation Impact performance

Effect of Reactivity of Quick Lime on the Properties of Hydrated Lime Sorbent for SO_2 Removal

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journal of Materials Science & Technology 2009年第3期25卷 329-332页

作者： H.G. Shin H. kim y.N. kim H.S. Lee Department of Materials Science and Engineering Seoul National University Material Analysis Team Korea Testing Laboratory School of Materials Science and Engineering Pusan National University

The hydration of quick lime and the sulfation of hydrated lime were carried out for verification of relationship between the reactivity of quick lime and the properties of hydrated lime as a sorbent. The effect of reactivity of quick lime was investigated with the change of calcination temperature and time. Results obtained showed that the temperature rise during the hydration of quick limes varied from 31 to 69℃ with the variation of calcination temperature and time. The specific surface area and the sulfation ability of hydrated lime prepared by hydration of quick lime showed a proportional relationship with the reactivity of quick lime. The hydrated lime which was prepared by hydration of quick lime calcined at 1100℃ had the highest reactivity and showed 41.53 m^2/g of the specific surface area, 0.16 cm^3/g of the pore volume and 87% of the removal efficiency for SO2 removal,

关键词： Reactivity Quick lime Hydrated lime Calcination Hydration Sorbent

Anisotropic NdFeB Magnet Fabricated by Single Stroke Hot Deformation

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journal of Materials Science & Technology 2000年第2期16卷 129-130页

作者： y.Li (Chungnam National University, Taejon, Korea) y.B.kim (Korea Research Institute of Standards and Science, Taejon, Korea) M.j.kim, M.S.Song, j.H.yang, T.K.kim and C.O.kim (Chungnam National University, Taejon, Korea) Chungnam National University Taejon South Korea Korea Research Institute of Standards and Science Taejon South Korea

The general hot deformation process consists of two steps, hot pressing and die-upsetting in order to obtain the anisotropic NdFeB magnet. This is the first report that the high anisotropy NdFeB magnets can be fabricated by single stroke hot deforming the isotropic magnet. The magnetic properties of those materials are: coercivity iHc ～11 kOe, remanence Br ～12 kG, and the maximum energy product (BH)max ～28 ***.

关键词： NdFeB Anisotropic NdFeB Magnet Fabricated by Single Stroke Hot Deformation

The Effect of Non-equilibrium Condensation on the Drag Coefficient in a Transonic Airfoil Flow

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journal of Thermal Science 2012年第6期21卷 518-524页

作者： I.W.kim M.M.A.Alam S.j.Lee y.D.Kwon S.B.Kwon School of Mechanical Engineering Kyungpook Nat.Uni.1370Sankyuk-dongDaegu 702-701Korea Dept.of Advanced & Control Eng.Saga Uni.japan

In this study, a transonic flow past NACA0012 profile at angle of attack α=0^0 whose aspect ratio AR is 1.0 with non-equilibrium condensation is analyzed by numerical analysis using a TVD scheme and is investigated using an intermittent indraft type supersonic wind tunnel. Transonic flows of 0.78-0.90 in free stream Mach number with the variations of the stagnation relative humidity（φ0） are tested. For the same free stream Mach number, the increase in φ0 causes decrease in the drag coefficient of profile which is composed of the drag components of form, viscous and wave. In the case of the same Moo and To, for more than φ0=30%, despite the irreversibility of process in non-equilibrium condensation, the drag by shock wave decreases considerably with the increase of φ0. On the other hand, it shows that the effect of condensation on the drag coefficients of form and viscous is negligible. As an example, the decreasing rate in the drag coefficient of profile caused by the influence of non-equilibrium condensation for the case of M∞=0.9 and φ0 =50% amounts to 34%. Also, it were turned out that the size of supersonic bubble （that is, the maximum height of supersonic zone） and the deviation of pressure coefficient from the value for M=1 decrease with the increase of φ0 for the same M∞.

关键词： Non-equilibrium condensation Transonic Moist air Drag coefficient Pressure coefficient

Degradation of Synthetic Dyeing Wastewater by Underwater Electrical Discharge Processes

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Plasma Science and Technology 2013年第7期15卷 659-665页

作者： S.D.kim D.I.jANG B.j.LIM S.B.LEE y.S.MOK yeongsan River Environment Research Center National Institute of Environmental ResearchGwangju 500-480 Korea Department of Chemical and Biological Engineering Jeju National UniversityJeju 690-756 Korea

Electrical discharge treatments of synthetic dyeing wastewater were carried out with two different systems： underwater pulsed electrical discharge （UPED） and underwater dielectric barrier discharge （UDBD）. Reactive Blue 4 （RB4） and Acid Red 4 （AR4） were used as model contaminants for the synthetic wastewater. The performance of the aforementioned systems was compared with respect to the chromaticity removal and the energy requirement. The results showed that the present electrical discharge systems were very effective for degradation of the dyes. The dependences of the dye degradation rate on treatment time, initial dye concentration, electrical energy, and the type of working gas including air, 02, and N2 were examined. The change in the initial dye concentration did not largely affect the degradation of either RB4 or AR4. The energy delivered to the UPED system was only partially utilized for generating reactive species capable of degrading the dyes, leading to higher energy requirement than the UDBD system. Among the working gases, the best performance was observed with O2. As the degradation proceeded, the concentration of total dissolved solids and the solution conductivity kept increasing while pH showed a decreasing trend, revealing that the dyes were effectively mineralized.

关键词： degradation dyeing wastewater pulsed electrical discharge dielectric barrierdischarge

Tooth regeneration: a revolution in stomatology and evolution in regenerative medicine

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International journal of Oral Science 2011年第3期3卷 107-116页

作者： Sibel yildirim Susan y. Fu Keith kim Hong Zhou Chang Hun Lee Ang Li Sahng Gyoon kim Shuang Wang jeremy.j. Mao Tissue Engineering and Regenerative Medicine Laboratory （TERML） Center for Craniofacial Regeneration Columbia University Medical Center New York NY 10032 USA Department of Basic Science Xi＇an Jiaotong University School of Stomatology Xi＇ an 710049 China

A tooth is a complex biological organ and consists of multiple tissues including the enamel, dentin, cementum and pulp. Tooth loss is the most common organ failure. Can a tooth be regenerated？ Can adult stem cells be orchestrated to regenerate tooth structures such as the enamel, dentin, cementum and dental pulp, or even an entire tooth？ If not, what are the therapeutically viable sources of stem cells for tooth regeneration？ Do stem cells necessarily need to be taken out of the body, and manipulated ex vivo before they are transplanted for tooth regeneration？ How can regenerated teeth be economically competitive with dental implants？ Would it be possible to make regenerated teeth affordable by a large segment of the population worldwide？ This review article explores existing and visionary approaches that address some of the above-mentioned questions. Tooth regeneration represents a revolution in stomatology as a shift in the paradigm from repair to regeneration： repair is by metal or artificial materials whereas regeneration is by biological restoration. Tooth regeneration is an extension of the concepts in the broad field of regenerative medicine to restore a tissue defect to its original form and function by biological substitutes.

关键词： stem cells bioactive cues biomaterials cell homing dental pulp tooth regeneration growth factors scaffold dental implants pulp regeneration

Strip Casting of High Performance Structural Alloys

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journal of Rare Earths 2004年第Z2期22卷 78-84页

作者： S S Park j G Lee Nack j kim Center for Advanced Aerospace Materials Pohang University of Science and TechnologyPohang 790-784Korea Center for Advanced Aerospace MaterialsPohang University of Science and TechnologyPohang 790-784Korea Center for Advanced Aerospace MaterialsPohang University of Science and TechnologyPohang 790-784Korea

There exists a great need for the development of high performance alloys due to increasing demands for energy conservation and environmental protection. Application of strip casting shows a strong potential for the improvement of properties of existing alloys and also for the development of novel alloy systems with superior properties. The present paper reviews our Center's activities in the development of high performance alloys by strip casting. Examples include (1) Al alloys, (2) wrought Mg alloys, and (3) bulk metallic glass (BMG) alloys.

关键词： strip casting 6061 Al alloy AZ Mg alloy bulk metallic glass (BMG) alloy dispersion hardening

Effects of Processing Parameters on Microstructure and Properties of Ultra High Strength Linepipe Steel

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journal of Materials Science & Technology 2012年第10期28卷 889-894页

作者： Xiaodan Wu Hakcheol Lee young Min kim Nack j.kim University of Pittsburgh Pittsburghl PA 15213USA Pohang University of Science and Technology Pohang 790-784Korea

To examine the effect of processing parameters on microstructural evolution and to obtain the excellent combination of strength and toughness, simulation of thermo-mechanical processing was conducted using the Gleeble machine. Trial production was then conducted under the conditions obtained by Gleeble tests. Based on the results of microstructure analysis and mechanical property evaluation, the relationship between microstructural features and mechanical properties was elucidated. The result shows that the volume fraction of constituted phases can be controlled through adjusting the cooling rate and finish cooling temperature in order to get different strength levels. As cooling rate increases, the volume fraction of upper bainite increases, which leads to the increase of strength. The upper shelf energy （USE） increases with increasing volume fraction of acicular ferrite in bainite base because of the small effective acicular ferrite grain size. Ductile-brittle transition temperature （DBTT） decreases with increasing acicular ferrite volume fraction. High reduction in the rough stage has great influence on grain refinement.

关键词： Linepipe steel Microstructure Gleeble test TMCP (thermomechanicalcontrol process)