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Microstructure and Mechanical Properties of AA1050/ AA6061/AA1050 Multi-Layer Sheet Fabricated by Cold Roll Bonding Process

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Lee S.-H.

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Microstructure and Mechanical Properties of AA1050/ AA6061/AA1050 Multi-Layer Sheet Fabricated by Cold Roll Bonding Process

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Lee S.-H.

Archives of Metallurgy and Materials

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2018

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tom Vol. 63, iss. 3

1489--1492

EN

A cold roll-bonding process was applied to fabricate an AA1050/AA6061/AA1050 multi-layer sheet. Three Al sheets in which an AA6061 sheet is inserted inside two AA1050 sheets of 2 mm thickness, 40 mm width and 300 mm length were stacked up after surface treatment, and the material was then reduced to a thickness of 1.0 mm by multi-pass cold rolling. The AA1050/AA6061/AA1050 laminate complex sheet fabricated by roll bonding was then hardened by a natural aging (T4) and an artificial aging (T6) treatments. The microstructures of the as-roll bonded and the age-hardened Al complex sheets were revealed by optical microscope and electron back scatter diffraction analysis, and the mechanical properties were investigated by tensile and hardness testing. The strength of the as-roll bonded complex sheet was found to increase by 2.6 times, compared to that value of the starting material. Both AA1050 and AA6061 showed a typical recrystallization structure in which the grains were equiaxed after heat treatment. However, the grain size was smaller in AA6061 than in AA1050.

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Identification of MsHsp23 gene using annealing control primer system

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Lee K.-W. , Kim K.-H. , Kim Y.-G. , Lee B. H. , Lee S.-H.

Acta Physiologiae Plantarum

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2012

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tom 34

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nr 2

EN

To identify potential candidates for acquiring stress tolerance, a new annealing control primer (ACP) system was used to identify the differentially expressed genes. Alfalfa (Medicago sativa L.) seedlings were exposed to various abiotic stresses such as cold (4°C for 6 h), heat (42°C for 6 h), salt (300 mM for 6 h), drought (withdrawing irrigation for 48 h), copper (500 µM for 6 h), cadmium (500 µM for 6 h), and arsenic (500 µM for 6 h). Primer sets 41 and 93 were differentially expressed and identified as same sequence, which represents a mitochondrial small heat-shock protein encoding gene, MsHsp23. This band was markedly increased or induced in alfalfa under heat, salt, and arsenic stresses. Differential expression of MsHsp23 was further evaluated by Northern blot analysis. Temporal expression analysis showed that mRNA pool was altered as early as 1 h of treatment. Thus, differential accumulation of MsHsp23 under heat, salt, and arsenic stresses suggests its potential involvement in diverse abiotic stress tolerance, and thereby making a target for further molecular analysis.

4

Characteristics Of The Porous Body Sintered By Nano-Sized Fe-Cr-Al Alloy Powder

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Lee S.-I. , Lee S.-H. , Gu B.-U. , Lee D.-W. , Kim B.-K.

Archives of Metallurgy and Materials

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2015

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tom Vol. 60, iss. 2B

1275--1279

EN

Porous metal with uniform honeycomb structure was successfully produced by sintering using Fe-Cr-Al nano powder, which was prepared by the pulsed wire evaporation (PWE) in ethanol. Its process consisted of the several steps; 1) coating on the surface of polyurethane sponge with the liquid droplets generated from the ethanol-based slurry where the Fe-Cr-Al nano powders were uniformly dispersed, 2) heat treatment of debinding to remove the polyurethane sponge and 3) sintering of the porous green body formed by Fe-Cr-Al nano powders. The strut thickness of porous Fe-Cr-Al was increased by the increase of spraying times in ESP step. Also, The shrinkages and the oxidation resistance of the sintered porous body was increased with increase of sintering temperature. The optimal sintering temperature was shown to 1450°C in views to maximize the oxidation resistance and sinterability.

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The effect of patterns on image-based modelling of texture-less objects

45%

Hafeez J. , Jeon H.-J. , Hamacher A. , Kwon S.-C. , Lee S.-H.

Metrology and Measurement Systems

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2018

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tom Vol. 25, nr 4

755--767

EN

The task of generating fast and accurate three-dimensional (3D) models of objects or scenes through a sequence of non-calibrated images is an active field of research. The recent development in algorithm optimization has resulted in many automatic solutions that can provide an accurate 3D model from texture-full objects. Structure-from-motion (SfM) is an image-based method that uses discriminative point-based feature identifier, such as SIFT, to locate feature points in the images. This method faces difficulties when presented with the objects made of homogenous or texture-less surfaces. To reconstruct such surfaces a well-known technique is to apply an artificial variety by covering the surface with a random texture pattern prior to the image capturing process. In this work, we designed three series of image patterns which are tested based on the contrast and density ratio which increases from the first to the last pattern within the same series. The performance of the patterns is evaluated by reconstructing the surface of a texture-less object and comparing it with the true data. Using the best-found patterns from the experiments, a 3D model of a Moai statue is reconstructed. The experimental results demonstrate that the density and structure of a pattern highly affects the quality of the reconstruction.

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Growth promotion and induced disease suppression of four vegetable crops by a selected plant growth-promoting rhizobacteria (PGPR) strain Bacillus subtilis 21-1 under two different soil conditions

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Lee S.-W. , Lee S.-H. , Balaraju K. , Park K.-S. , Nam K.-W. , Park J.-W. , Park K.

Acta Physiologiae Plantarum

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2014

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tom 36

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nr 06

EN

This study aimed at investigating the efficacy of a PGPR strain, Bacillus subtilis 21-1 (BS21-1), under two different soil conditions for plant growth promotion and disease suppression. BS21-1 treatment significantly (P<0.05) promoted plant growth as measured by plant height and leaf width and increased the seed germination rate in organic soil (OS) compared with seed bed soil (SBS). In Chinese cabbage and lettuce, soft rot disease was reduced to 45 and 23.5 %, respectively, by BS21-1, and to 33 and 52.5 %, respectively, by benzo-(1,2,3)-thidiazole-7-carbothioic acid S-methyl ester (BTH) treatments in OS compared with SBS. These levels of disease suppression were greater than those found in the water-treated control upon pathogen challenge. There was a greater reduction of anthracnose lesions on the leaves of cucumber plants treated with BS21-1 and BTH in OS when compared with SBS. Botrytis rot disease in tomato caused by Botrytis cinerea was drastically reduced to 2 % in OS and 4 % in SBS by BS21-1 treatment. In the four plants studied, there was increased disease suppression in OS compared with SBS. Upon treatment with BS21-1, there was an increased expression of the PR-1a gene by β-gulcuronidase (GUS) activity in tobacco (Nicotiana tabacum L. cv. Xanthi-nc) plants in OS compared with SBS, which indicates a possible role of the SA pathway in BS21-1 mediated plant protection. Thus, the isolate BS21-1 could effectively be used as one of the biocontrol agents for disease suppression in four vegetable crops through systemic resistance and for plant growth promotion.

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Molecular detection and assessment of risk factors for tick-borne diseases in sheep and goats from Turkey

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Benedicto B. , Ceylan O. , Moumoumi P. F. A. , Lee S.-H. , Tumwebaze M. A. , Li J. , Galon E. M. , Liu M. , Li Y. , Ji S. , Ringo A. , Rizk M. , Sevinc F. , Xuan X.

Acta Parasitologica

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2020

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tom 65

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nr 3

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Responses of MxPPO overexpressing transgenic tall fescue plants to two diphenyl-ether herbicides, oxyfluorfen and acifluorfen

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Lee K.-W. , Ahsan N. , Lee S.-H. , Lee D.-G. , Kim K.-H. , Alam I. , Kwon S.-Y. , Kim J.-S. , Back K. , Lee S. S. , Lee B.-H.

Acta Physiologiae Plantarum

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2008

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tom 30

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nr 5

EN

We generated transgenic tall fescue (Festuca arundinacea Schreb. cv. Kentucky-31) plants harboring a synthetic Myxococcus xanthus protoporphyrinogen oxidase (MxPPO) gene through Agrobacterium-mediated gene transfer. Successful integration of the transgene into the genome of transgenic plants confirmed by polymerase chain reaction (PCR) and Southern blot analysis, and the functional expression of the MxPPO gene at the mRNA level in transgenic lines was validated by Northern blot analysis. Responses of transgenic and non-transgenic tall fescue plants to diphenyl-ether herbicides such as oxyfluorfen and acifluorfen have been evaluated in respect of various physiological and biochemical parameters. Differential responses were observed in chlorophyll content, in vivo H2O2 deposition and lipid peroxidation in both transgenic and non-transgenic plants exposed to oxyfluorfen or acifluorfen. Isozyme profiles of four antioxidantenzymes, including peroxidase (POD), catalase (CAT), superoxide dismutase (SOD) and ascorbate peroxidase (APX), were also investigated in transgenic and nontransgenic plants using native PAGE analysis. Compared to the transgenic lines, higher staining activities of the examined antioxidant-enzymes observed in non-transgenic plants subjected to 100 μM of oxyfluorfen or acifluorfen suggests that non-transgenic plants are unable to prevent the photodynamic induced oxidative stress caused by herbicides. In addition, both transgenic and non-transgenic plants exposed to oxyfluorfen exhibited proportionally increased band-staining patterns in contrast to acifluorfen,which suggests that oxyfluorfen has relatively greater or more rapid effects on leaves than acifluorfen.