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A comparison of transmittance properties between ZnO∶Al films for transparent conductors for solar cells deposited by sputtering of AZO and cosputtering of AZO/ZnO

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Rare Metals 2006年第Z1期25卷 105-109页

作者： lee Chongmu YIM Keunbin CHO Youngjoon lee j.G. Department of Materials Science and Engineering Inha University 253 Yonghyeon-dong Incheon 402-751 Korea School of Advanced Materials Engineering Kookmin University Seoul 136-702

Aluminum-doped zinc oxide (AZO) thin films were deposited on sapphire (002) and glass substrates by two different sputtering techniques radio frequency magnetron cosputtering of AZO and ZnO targets and sputtering of an AZO target. The dependence of the photoluminescence (PL) and transmittance properties of the AZO films deposited by cosputtering and sputtering on the AZO/ZnO target power ratio, R and the O2/Ar flow ratio, r were investigated, respectively. Only a deep level emission peak appears in the PL spectra of cosputtered AZO films whereas both UV emission and deep level emission peaks are observed in the PL spectra of sputtered AZO films. The absorption edges in the transmittance spectra of the AZO films shift to the lower wavelength region as R and r increase. Effects of crystallinity, surface roughness, PL on the transmittance of the AZO films were also explained using the X-ray diffraction (XRD), atomic force microscopy (AFM), and PL analysis results.

关键词： Al-doped ZnO (AZO) R.F. magnetron sputtering R.F. power transparent conducting oxide (TCO) transmittance

Microstructure and tensile properties of magnesium nanocomposites fabricated using magnesium chips and carbon black

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journal of Magnesium and Alloys 2020年第3期8卷 860-872页

作者： T.j.lee W.j.Kim Department of Materials Science and Engineering Hongik UniversityMapo-guSangsu-dong 72-1Seoul 121-791Republic of Korea

In this study,carbon black(0,0.01,0.03 and 0.08 wt%)and AZ31(Mg-3Al-lZn)magnesium chips were used to fabricate carbon black-reinforced magnesium matrix composites with extrusion or a combination of extrusion and high-ratio differential speed *** hot pressing at 693 K and extrusion at 623 K with an extrusion ratio of 22,the magnesium chips coated with carbon black were soundly bonded into a bulk composite *** grain sizes of the extruded materials were similar with a size of 48.2-51.5|im despite the difference in the amount of carbon *** yield strength and ultimate tensile strength increased from 177 to 191 MPa and from 240 to 265 MPa,respectively,as a result of the addition of 0.01%carbon black;however,a further increase in the strength was marginal with additional carbon *** same trend was observed in the strain hardening *** tensile elongation increased by to the addition of 0.01%carbon black(from 15.8%to 17.4%)due to the increased work hardening effect,but decreased with additional carbon black due to its agglomeration and poor dispersion at higher *** high-ratio differential speed rolling(HRDSR)on the extruded materials and subsequent annealing,the AZ31 and AZ31 composites had a similar fine grain size of 16.3-17.9 *** annealed HRDSR composites showed the best mechanical properties at a higher content of carbon black(0.03%)compared to that(0.01%)for the extruded *** resulted from the enhanced dispersion effect of the carbon black due to the high shear flow induced during the HRDSR *** extruded composites exhibited the three distinct hardening stages(stage II,stage III and stage IV),while the annealed HRDSR composites mainly displayed the stage III *** addition of carbon black increased the strain hardening rate at all the strain hardening stages in both of the extruded and annealed HRDSR *** the initial hardening stage,the strain hardening rates of the extruded comp

关键词： Recycling Magnesium alloys chips Carbon black Nanocomposites Extrusion Differential speed rolling

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A1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

Carbide Formation Process in Directionally Solidified MAR-M247 LC Superalloy

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journal of Materials Science & Technology 1999年第1期15卷 48-52页

作者： Chen, jian Huang, Baiyun lee, j.H. Choe, S.j. lee, Y.T. Cent S Univ Technol Powder Met Res Inst Changsha 410083 Peoples R China Changwon Natl Univ Dept Met & Mat Sci Changwon 641773 South Korea Korea Inst Machinery & Mat Changwon 641010 South Korea

Carbide nucleation, growth and trapping behavior in directionally solidified MAR-M247 LC alloy and the corresponding mechanism have been investigated. Carbide forming element enrichment controls the carbide nucleation and the carbide growth behavior. If the carbide forming element enrichment and the nucleation sites are suitable, carbide nucleation can occur both above and below the liquids temperature. Heterogeneous carbide nucleation is the preferred nucleation mechanism at low carbide forming element enrichment. Carbide growth occurs mainly at inter-secondary gamma dendrite arm area and lower part of the mushy zone. The carbides are subsequently trapped at these positions after growing to a certain size. Some carbides are only partially trapped by the solid-liquid interface and the carbide growth accelerates after being partially trapped. A critical growth rate exists between 2 multiplied by 10** minus **6 m/s and 5 multiplied by 10** minus **6 m/s. The carbide volume fraction decreases in the directionally solidified part at slow growth rate which is caused by the lack of suitable growth site and the low trapping ability of the solid-liquid interface. (Edited author abstract) 16 Refs.

关键词： Nickel alloys

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

Effect of 1Al addition on deformation behavior of Mg

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journal of Magnesium and Alloys 2021年第2期9卷 489-498页

作者： ji Hyun Hwang A.Zargaran Gyeongbae Park O.lee B.-j.lee Nack j.Kim Center for Advanced Aerospace Materials Pohang University of Science and Technology(POSTECH)PohangSouth Korea

Deformation behavior of 1 Al containing Mg alloy has been investigated in the present *** annealing,the Mg-1 Al alloy shows a typical basal *** compared to the pure Mg having a similar texture and grain size,the Mg-1 Al alloy shows much higher strength and larger *** trace analyses of the tensile strained specimens show that non-basal slips such as pyramidal I and II slips can be easily activated at an early stage of deformation in the Mg-1 Al alloy and the grains in the Mg-1 Al alloy are seen to accommodate a larger degree of deformation than those in the pure Mg at a given *** increasing tensile strain,however,there is a strain localization along the initially formed slip lines of non-basal slips,forming surface steps without activating multiple slip lines.

关键词： Deformation behavior Slip trace analysis Non-basal slip Strain localization Ductility

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

Mending the broken in amyotrophic lateral sclerosis: DNA damage and repair in motor neuron degeneration

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Neural Regeneration Research 2021年第1期16卷 104-105页

作者： Byung Woo Kim lee j.Martin Department of Pathology Division of Neuropathologythe Pathobiology Graduate Training ProgramJohns Hopkins University School of MedicineBaltimoreMDUSA Department of Neuroscience Johns Hopkins University School of MedicineBaltimoreMDUSA

Amyotrophic lateral sclerosis(ALS)is a fatal neurodegenerative disease that causes paralysis and respiratory failure(Petrov et al.,2017).The driving mechanisms are unknown,and there are no effective treatments(Petrov et al.,2017).Aging and a few gene mutations,a common one being missense mutations in superoxide dismutase-1(SOD1),are risk factors for ALS(Figure 1).The recent Food and Drug Administration approval of edaravone for the treatment of ALS putatively supports a role for oxidative and nitrative stresses in the disease processes(Figure 1A).DNA damage,abnormalities in DNA repair,and other nuclear abnormalities are implicated also in the pathogenesis of human ALS(Bradley and Krasin,1982;Kim et al.,2020).

关键词： al. damage degeneration

Integrating innovations:a qualitative analysis of referral non-completion among rapid diagnostic test-positive patients in Uganda’s human African trypanosomiasis elimination programme

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Infectious Diseases of Poverty 2018年第1期7卷 844-859页

作者： Shona j.lee jennifer j.Palmer Centre of African Studies University of EdinburghGeorge SquareEdinburgh EH89LDUK Health in Humanitarian Crises Centre London School of Hygiene&Tropical MedicineKeppel StreetLondon WC1E 7HTUK.

Background:The recent development of rapid diagnostic tests(RDTs)for human African trypanosomiasis(HAT)enables elimination programmes to decentralise serological screening services to frontline health ***,patients must still undertake multiple onwards referral steps to either be confirmed or discounted as *** surveillance thus relies not only on the performance of diagnostic technologies but also on referral support structures and patient *** study explored why some RDT-positive suspects failed to complete the diagnostic referral process in West Nile,***:Between August 2013 and june 2015,85%(295/346)people who screened RDT-positive were examined by microscopy at least once;10 cases were *** interviewed 20 RDT-positive suspects who had not completed referral(16 who had not presented for their first microscopy examination,and 4 who had not returned for a second to dismiss them as cases after receiving discordant[RDT-positive,but microscopy-negative results]).Interviews were analysed thematically to examine experiences of each step of the referral ***:Poor provider communication about HAT RDT results helped explain non-completion of referrals in our *** patients were unaware they were tested for HAT until receiving results,and some did not know they had screened *** HAT testing and treatment is free,anticipated costs for transportation and ancillary health services fees deterred *** expected a positive RDT result would lead to HAT *** results that failed to provide a definitive diagnosis without further testing led some to question the expertise of health *** the four individuals who missed their second examination,complying with repeat referral requests was less attractive when no alternative diagnostic advice or treatment was ***:An RDT-based surveillance strategy that relies on referral through all levels of the health system is inevitably sub

关键词： Human African trypanosomiasis Sleeping sickness Uganda Passive screening Diagnostics Case detection Referral completion Rapid diagnostic tests Elimination