• Title/Summary/Keyword: Lee Sam

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Analyses of Stress Intensity Factors and Evaluation of Fracture Toughness in Adhesively Bonded DCB Joints (DCB 접착이음에 대한 응력세기계수의 해석 및 파괴인성의 평가)

  • Jeong, Nam-Yong;Lee, Myeong-Dae;Gang, Sam-Geun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.6 s.177
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    • pp.1547-1556
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    • 2000
  • In this paper, an evaluation method of fracture toughness to apply interfacial fracture mechanics was investigated in adhesively bonded double-cantilever beam (DCB) joints. Four types of adhesively bonded DCB joints with an interface crack were prepared for analyses of the stress intensity factors using boundary element method(BEM) and the fracture toughness test. From the results of BEM analysis and fracture toughness experiments, it is found that the stress intensity factor, K1 is a parameter driving the fracture of adhesively bonded joints. Also, the evaluation method of fracture toughness by separated stress intensity factors of mixed mode cracks was proposed and the influences of mode components for its fracture toughness are investigated in adhesively bonded DCB joints.

Bending Analysis of Reinforced Tube Beams (굽힘하중을 받는 보강 사각관 보의 좌굴변형거동 해석)

  • Choi, Nak-Sam;Lee, Sung-Hyuk
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.60-65
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    • 2007
  • Local buckling behaviors of aluminum square tube beams reinforced by aluminum plates under three point bending loads have been analyzed using experimental tests combined with theoretical and finite element analyses. For this analysis true stresses were determined from applied loads and cross-sectional area records of a tensile specimen with a rectangular cross-section by real-time photographing. True strains were also obtained from in-situ local elongation measurements of the specimen gage portion by the multi-point scanning laser extensometer. Six kinds of aluminum tube beam specimens reinforced by aluminum plates were employed for the bending test. The bending deformation behaviors up to the maximum load analyzed by the numerical simulation agreed well with experimental ones. After passing the maximum load, reinforcing plate hindering the local buckling of the tube beam was debonded from the aluminum tube beam. An aluminum tube beam strengthened by aluminum plate on the upper web showed the most excellent bending capacity, which could be explained on the basis of the neutral axis shift and the local buckling deformation range.

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Identification and Characterization of Protein Arginine Methyltransferase 1 in Acanthamoeba castellanii

  • Moon, Eun-Kyung;Kong, Hyun-Hee;Hong, Yeonchul;Lee, Hae-Ahm;Quan, Fu-Shi
    • Parasites, Hosts and Diseases
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    • v.55 no.2
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    • pp.109-114
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    • 2017
  • Protein arginine methyltransferase (PRMT) is an important epigenetic regulator in eukaryotic cells. During encystation, an essential process for Acanthamoeba survival, the expression of a lot of genes involved in the encystation process has to be regulated in order to be induced or inhibited. However, the regulation mechanism of these genes is yet unknown. In this study, the full-length 1,059 bp cDNA sequence of Acanthamoeba castellanii PRMT1 (AcPRMT1) was cloned for the first time. The AcPRMT1 protein comprised of 352 amino acids with a SAM-dependent methyltransferase PRMT-type domain. The expression level of AcPRMT1 was highly increased during encystation of A. castellanii. The EGFP-AcPRMT1 fusion protein was distributed over the cytoplasm, but it was mainly localized in the nucleus of Acanthamoeba. Knock down of AcPRMT1 by synthetic siRNA with a complementary sequence failed to form mature cysts. These findings suggested that AcPRMT1 plays a critical role in the regulation of encystation of A. castellanii. The target gene of AcPRMT1 regulation and the detailed mechanisms need to be investigated by further studies.

Phytochemical Studies on Lonicera Caulis (2) - Aliphatic and Phenolic Compounds (인동의 성분연구 (2) - 지방족 및 페놀성 화합물)

  • Kim, Ju-Sun;Yean, Min-Hye;Seo, Hyun-Kyu;Lee, Je-Hyun;Kang, Sam-Sik
    • Korean Journal of Pharmacognosy
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    • v.40 no.4
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    • pp.326-333
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    • 2009
  • Fourteen compounds were isolated from the 70% ethanol extract of Lonicera Caulis (Caprifoliaceae) and their structures were identified as seven aliphatic compounds [long-chain alcohols (1, 2), trilinolein (3), hexacosanol (4), fatty acids (6), 9,12,13-trihydroxyoctadeca-10(E),15(Z)-dienoic acid (10), and pinellic acid (11)] and seven phenolics [bis(2-ethylhexyl) phthalate (dioctylphthalate, DOP) (5), coniferaldehyde (7), caffeic acid docosanoyl ester (8), caffeic acid (9), coniferyl aldehyde 4-O-glucoside (12), linarin (13), and coniferin (14)]. The chemical structures of these compounds were identified on the basis of spectroscopic methods and comparison with literature values. All the compounds except for caffeic acid (9) were isolated from this plant parts for the first time.

Verification of The Variable-Speed Wind Turbine Control System by Using the Simulator (시뮬레이터를 이용한 가변속 풍력발전기 제어시스템 검증)

  • Cha, Sam-Gon;Han, Sang-Yul;Cha, Jong-Hwan;Choi, Won-Ho;Lee, Seung-Kuh
    • 한국신재생에너지학회:학술대회논문집
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    • 2007.06a
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    • pp.370-373
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    • 2007
  • For the development of wind turbine, generally simulator is used. Simulator include wind turbine components. e.g blades, pitch and pitching method, rotor, yaw system, tower, drive train and so on. Few the more, it include a external circumstance. e.g wind speed, wind direction, air density. these basic parameters be used for the control of wind turbine by wind turbine controller in wind turbine simulator. The wind turbine controller can be designed in the wind turbine simulator. But a developer must make the real control system that will be made using PLC or PC or other processor. The developer must verify the function of control system. that is control algorithm , I/O function, communication, sequence and so on. This verification is possible if we substitute the real wind turbine control system for wind turbine controller in the simulator.

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Study on Dual-Lenses Actuator for HD-DVD System (차세대 DVD 시스템용 Actuator 연구)

  • Kim, Seok-Jung;Lee, Yong-Hoon;Ahn, Young-Man;Chung, Chong-Sam
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.11b
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    • pp.777-781
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    • 2002
  • Recently, an optical disc system has been proposed using blue laser diode, high NA objective lens and groove only disc structure. A new method is needed to readout CD and DVD in this blue system. In order to readout CD and DVD in HD-DVD system, we adopted dual-lenses actuator in consideration of optical utilization efficiency, optical performance and insurance of sufficient W.D (working distance). This dual-lenses actuator has two objectives in radial direction, one is for CD/DVD and the other is for HD-DVD. We had to solve the induced problems of DC tilt increase, $2^{nd}$ resonance deterioration and AC sensitivity drop caused by disposing two lenses in an actuator. Especially, to solve AC sensitivity drop, we introduced two 2-pole magnets and separated focus and track magnetic circuits. Consequently we presented that dual-lenses actuator has been possessed good performance. And we measured eye patterns of CD, DVD and HD-DVD by using HD-DVD optical pick-up with dual-lenses actuator.

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A LIM Protein Gene Homologue of Protaetia brevitarsis: cDNA Cloning and mRNA Expression

  • Kim Iksoo;Choi Yong Soo;Lee Sun Young;Kim Mi Ae;Kim Seong Ryul;Hwang Jae Sam;Jin Byung Rae
    • International Journal of Industrial Entomology and Biomaterials
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    • v.11 no.1
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    • pp.71-74
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    • 2005
  • A LIM protein gene homologue of the CRP (cysteine­rich protein) family in the whiter-spotted flower chafer, Protaetia brevitarsis, was cloned. The P. brevitarsis LIM protein cDNA encodes a 92 amino acid polypep­tide with a predicted molecular mass of 10,030 Da and a pI of 8.57. The P. brevitarsis LIM protein contains the cysteine-rich consensus sequence of LIM domain and the glycine-rich consensus sequence observed in the cysteine-rich protein family 1 (CRPl). The potential nuclear targeting signal is retained. The deduced amino acid sequence of the P. brevitarsis LIM protein cDNA showed 92$\%$ identity to another beetle, Apriona germari LIM protein. Northern blot analysis showed that P. brevitarsis LIM protein is highly expressed in epidermis and midgut, but not in the fat body.

Characterization of Ligands-Conjugated AuNPs by Using ToF-SIMS Imaging Technique

  • Shon, Hyun Kyong;Xaba, Morena Sam;Gulumian, Mary;Song, Nam Woong;Lee, Tae Geol
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.02a
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    • pp.278-278
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    • 2013
  • 최근 나노 입자의 안전성에 대한 연구가 활발하게 이루어 지고 있다. 대부분의 연구는 세포독성과 쥐에 흡입시켜 각 장기에 침착 정도를 측정하는 연구에 집중되어 있고, 나노입자의 리간드 특성에 대한 연구는 활발이 진행되고 있지 않다. 따라서 같은 나노입자를 이용한 연구결과가 다르게 나타나는 것을 종종 확인 할 수 있어서, 나노입자 특성평가의 중요성이 커지고 있다 [1,2]. 본 연구에서는 용매에 리간드가 존재하는 PEG-conjugated AuNPs과 원심분리로 용액내의 free-ligands가 제거된 PEG-conjugated AuNPs에 대하여 ToF-SIMS 이미지를 얻었고, PEG와 AuNPs 이미지의 statistical correlation으로부터 AuNPs의 표면에 존재하는 리간드들의 stability를 평가할 수 있는 방법을 개발하였다. 또한, citrated-conjugated AuNPs을 PEG 리간드로 표면을 치완시키고, phagolysosomal simulant Fulid(PSF) 용액에 incubation 과정 동안의 PEG 리간드가 표면에서 제거되어 용액에 존재함을 확인하였다. ToF-SIMS의 이미지와 statistical correlation을 이용하면 나노입자의 표면에 존재하는 다양한 리간드들의 안정성을 평가할 수 있고, 이를 통한 나노입자의 안전성에 대한 연구에 기여 할 수 있을 것으로 기대된다.

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Color Differences of Standard Samples according to Their Lightness Levels (명도 수준에 다른 목표 샘플의 색차)

  • Kim Jeong Ryeol;Lee Seung Jun;Kim Sam Soo
    • Textile Coloration and Finishing
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    • v.17 no.2 s.81
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    • pp.19-25
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    • 2005
  • A colour-difference formulae would be based on a colour appearance model, but, So far, most colour-difference formulae in common use are based on empirical fits to data. Therefore, of the many proposed, none are completely satisfactory but advances have been made in recent years. A new color-difference data set has been produced with the aims of making a comparison of the advanced CIE Lab formulae as well as confirming the effect of color-difference. 416 low lightness pairs that have only lightness-difference were produced for evaluation of CIE Lab-based formulae on lightness-difference from glossy polyester fabric. The standard color-difference pair was prepared and used. It was neutral grey sample pair that has only lightness difference. The standard pair was used to investigate lightness tolerances. And grey-scale method used to evaluate visual assessment. CIE Lab coordinates of the samples were measured using a X-Rite 8200 spectrophotometer. Visual assessments were carried out using Gretag Macbeth The Judge II Light Booth. A study of color tolerances at low lightness was carried out and get avaliable some results.

Antimicrobial Activity of the Scolopendrasin V Peptide Identified from the Centipede Scolopendra subspinipes mutilans

  • Lee, Joon Ha;Kim, In-Woo;Kim, Mi-Ae;Ahn, Mi-Young;Yun, Eun-Young;Hwang, Jae Sam
    • Journal of Microbiology and Biotechnology
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    • v.27 no.1
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    • pp.43-48
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    • 2017
  • In a previous study, we analyzed the transcriptome of Scolopendra subspinipes mutilans using next-generation sequencing technology and identified several antimicrobial peptide candidates. One of the peptides, scolopendrasin V, was selected based on the physicochemical properties of antimicrobial peptides using a bioinformatics strategy. In this study, we assessed the antimicrobial activities of scolopendrasin V using the radial diffusion assay and colony count assay. We also investigated the mode of action of scolopendrasin V using flow cytometry. We found that scolopendrasin V's mechanism of action involved binding to the surface of microorganisms via a specific interaction with lipopolysaccharides, lipoteichoic acid, and peptidoglycans, which are components of the bacterial membrane. These results provide a basis for developing peptide antibiotics.