• Title/Summary/Keyword: structural material.

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Design of Riser in 1MW OTEC system mounted on Floating Barge (해상 부유식 1MW 해수온도차발전 시스템의 라이저 설계)

  • Kwon, YongJu;Jung, DongHo;Kim, HyeonJu
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.18 no.1
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    • pp.22-28
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    • 2015
  • The design on a riser in 1MW OTEC system is performed. The minimum diameter of the riser is decided depending on intake quantity of deep-sea water to supply an OTEC cycle. An applicable pipe material is selected from analyzing the properties of commercial pipes. The selected HDPE pipe with the low density and strength is reinforced with a lumped block attached at the end of and wire ropes along the riser. A lumped block, connected to a floating structure by wire ropes, with 25% and 50% weight of a GFRP riser is designed to be attached the end of a riser. The structural safety of the HDPE riser with wire rope supporting axial loads induced by a lumped block is analyzed under the harsh ocean environmental condition near Hawaii ocean with the numerical method. The final dimension of the riser and accessories is determined considering the economic point of view. The designed riser will be applicable to the construction of the 1 MW OTEC pilot plant.

Scientific Conservation Treatment of the Celadon Jar with the Inscription of 'the Fourth Sunhwa Year'(National Treasure No.326) (국보 제326호 청자 '순화4년'명 항아리의 과학적 보존처리)

  • Lee, Sun Myung;Kwon, Oh Young;Park, Jongseo;Han, Woo Rim
    • Journal of Conservation Science
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    • v.35 no.5
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    • pp.453-469
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    • 2019
  • The celadon jar with inscription of 'the Fourth Sunhwa Year' is an important chronology that shows the conditions of production of the early celadon due to the inscription on the bottom including its purpose, application, and the producer. This celadon jar has been restored several times in the past. However, concerns over the structural stability, such as the separation and level differences in the joined cracks, have risen because of the aging of the repair materials, which were subjected to various environmental changes over a long time. By examining the conditions of preservation, the major damage was identified as the '入' shaped crack on the front, the 'V' shaped restored part and the crack on its left side, and the 'J' shaped crack on the back side. In the past, the cracks were found to be joined using a refined lacquer containing camphor, drying oil, rosin, etc. mixed with soil powder. The joint line was repainted with the refined lacquer and covered with gold powder. The missing parts were restored with gypsum and colored with acrylic color. After that, the repair materials were aged and emergency treatment was performed at the National Museum of Korea in 1981. At that time, Cemedine C or Cemedine C mixed with microballoons was used for reinforcing the cracks. Conservation treatment focused on removing the past repair materials and reinforcing the physically fragile parts by joining and restoring them based on the examination of the preservation condition. in addition, the area around the restored part was colored for future exhibition.

Study on Identification and Purification of Germanium-fortified Yeast (게르마늄강화효모의 게르마늄결합 단백질의 분리 및 확인에 관한 연구)

  • Lee, Sung-Hee;Lee, Sang-Kwang;Lee, Hyun-Joo;Yi, Yong-Sub;Park, Eun-Woo
    • Applied Biological Chemistry
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    • v.49 no.1
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    • pp.55-59
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    • 2006
  • This study was designed to investigate the optimum manufacturing condition of germanium-fortified yeast, and the binding properties of germanium (Ge) in germanium-fortified yeast. The nutritional optimum conditions were glucose 3.0 (w/v) %, yeast extracts 0.3 (w/v) % and peptone 0.5 (w/v) %, and the amounts of yeast cells were 67.4 mg/ml. And, the standard germanium-fortified yeast was produced under the condition at the ratio of yeast cell and germanium solution was 1 : 0.5 (50%), pH 6.5 and $35-40^{\circ}C$ during fermentation. In results of the identification, binding of germanium-protein showed structural difference between the inorganic Ge $(GeO_2)$ added during fermentation process and germanium-fortified yeast. Therefore, germanium-fortified yeast made by biosynthetic technology formed structurally safe organic germanium during fermentation process. Germanium-fortified yeast can be applied as a new functional material far the improvement of health, the prevention and treatment of chronic degenerative disease like cancer, and the enforcement of immune system.

A Study on Interorganizational Boundary Spanning Behaviors between Buyers and Sellers (유통경로 내 조직간 영역초월행동에 관한 연구)

  • Kim, Sang-Deok
    • Proceedings of the Korean DIstribution Association Conference
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    • 2007.08a
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    • pp.3-26
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    • 2007
  • Recently, both scholars and marketers have asserted the importance of boundary spanning behaviors, such as external representation, being vocal advocates to outsiders of the organization's image, goods, and services, internal influence, taking individual initiative in communications to the firm and co-workers to improve service delivery by the organization, co-workers, and oneself, and service delivery, serving customers in a conscientious, responsive, flexible, and courteous manner. However, there is lack of study dealing with bourdary spanning behaviors bewteen organizational dyads, in which boundary spanning behaviors are expected to have important roles. The objectives of this paper is to investigate these important concerns with prior research by developing a theoretical model predicting how distinct buyer's boundary spanning behaviors occur. To be concrete, this paper develops a seller characteristics-based model of the attitudinal antecedents of three conceptually distinct forms of boundary spanning behaviors, and tests the hypothesized differential effects of seller characteristics on the three forms of boundary spanning behaviors, and investigates the extent to which these relationships are mediated by relationship satisfaction and organizational commitment. For the purpose of empirical testing, 420 respondents of leading automobile dealers, dining franchisees, industrial material retailers in Korea were surveyed and the analysis utilizing structural equation model indicated that communication quality, fairness, and marketing program dynamism had positive effects on buyer's boundary spanning behaviors via relationship satisfaction and organizational commitment. In addition, boundary spanning behaviors occurred more in contractural and corporate distribution channel than in conventional distribution channel.

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Investigation of Nanofiber and Thermosensitive Scaffold for Intervertebral Disc through Organ Culture (기관배양을 통한 추간판 재생용 나노파이버 및 온도 감응성 지지체에 대한 검증)

  • Lee, Yong-Jae;Shin, Ji-Won;Shin, Ho-Jun;Kim, Chan-Hwan;Park, Ki-Dong;Bae, Jin-Woo;Seo, Hyoung-Yeon;Kim, Young-Jick;Shin, Jung-Woog
    • Journal of Biomedical Engineering Research
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    • v.28 no.4
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    • pp.512-519
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    • 2007
  • The purpose of this study is to investigate the potential of a novel tissue engineering approach to regenerate intervertebral disc. In this study, thermosensitive scaffold (chitosan-Pluronic hydrogel) and nanofiber were used to replace the nucleus pulposus (NP) and annulus fibrosus of a degenerated intervertebral disc, leading to an eventual regeneration of the disc using the minimally invasive surgical procedure and organ culture. In preliminary study, disc cells were seeded into the scaffolds and cellular responses were assessed by MTT assay and scanning electron microscopy (SEM). Based on these results, we could know that tissue engineered scaffolds might provide favorable environments for the regeneration of tissues. Organ culture was performed in fresh porcine spinal motion segments with endplates on both sides. These spinal motion segments were classified into three groups: control (Intact), injured NP (Defect), and inserting tissue engineered scaffolds (Insert). The specimens were cultivated for 7 days, subsequently structural stability, cell proliferation and morphological changes were evaluated by the relaxation time, quantity of DNA, GAG and histological examination. In these results, inserting group showed higher relaxation time, reduced decrement of DNA contents, and accumulated GAG amount. Consequently, the tissue engineered scaffolds used in this study seen to be a promising base scaffolds for regenerative intervertebral disc due to its capacity to absorb external dynamic loading and the possible ideal environment provided for disc cell growing.

A Steel Spacing for Crack Control in RC Flexural Members with an Effective Modulus of Elastic (유효탄성계수를 반영한 철근콘크리트 휨부재의 균열제어를 위한 철근 간격)

  • Choi, Seung-Won
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.5
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    • pp.98-105
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    • 2018
  • Cracks in RC members occurred as a result of material and structural factors. The crack width and a crack location are very difficult to examine. A direct crack control method and indirect crack control method to control a crack are presented in the KHBDC (LSD) and KSCDC (2012). In the KSCDC text, cracks are controlled by steel spacing indirectly under a service load. On the other hand, in the KSCDC appendix, cracks are controlled by a crack width directly under a sustained load. In particular, the loading state considered is different. On the other hand, cracks are controlled under a combination of service load and an effective elastic modulus is used in KHBDC. Therefore, in this study, an effective elastic modulus that can reflect the ratio of the sustained load and live load was applied, and a maximum steel spacing was calculated through a design crack width. A variable interpretation was carried out, and a rational crack control method was assessed. As a result, a steel spacing through the design crack width in the KSCDC was smaller than that from the design crack width in the KHBDC, which leads to a conservative design. In addition, the maximum steel spacing suggested in this study has a consistency eliminating the difference between direct crack control and indirect crack control.

The Vibration Effect by Induced Pulsation Pressure to the Fatigue Crack of the Dampener Fitting Welding Zone (항공기용 유압 펌프의 맥동 압력에 의한 감쇄기 용접부위 균열 개선 연구)

  • Shin, Jae Hyuk;Kim, Tae Hwan;Kang, Gu Heon;Ha, Do Jun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.7
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    • pp.677-687
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    • 2017
  • Aircraft can often be exposed to a variety of environments and vibrations such as engine, hydraulic pump, aerodynamic force. These may cause cracking and destruction of the mechanical structure and sub-components by high-cycle fatigue. The axial piston type pump which is usually applied to the aircraft hydraulic pump can be necessarily accompanied by the fluid pulsation by continuous rotation of the axial piston. The fatigue crack was identified at the dampener fitting welding zone to prevent vibration damping during the running of aircraft equipped with this type of pulsation hydraulic pump. In order to understand the root cause of this matter, fracture and component analyses were carried out and also integral type dampener fitting was applied to prevent recurrence of the crack as a subject of design improvements. Structural integrity stress analysis, fatigue analysis, qualification test and aircraft system equipped test was conducted to verify the design validity in application to integral type dampener fitting. The test results were sufficiently satisfactory with the demand lifetime of the material from the various types of test as conducted and the subject of design improvement in this study could be objectively evaluated that shall be applied to the operational aircraft.

Stratigraphical Research of the Quaternary Deposits in the Korean Peninsula (韓半島 第四紀 地層의 層序的 考察)

  • Lee, Dong-Young
    • The Korean Journal of Quaternary Research
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    • v.1 no.1
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    • pp.3-20
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    • 1987
  • With regard to the Quaternary formations in the Korean Peninsula, very few studies have been done specially from a stratigraphic viewpoint. The alluvial sediments filling in the valleys have often been considered as the only formation of Quaternary age (more precisely of the Holocone) and so the Pleistocene was regarded as an erosional or nondepositional episode. This is apparently evident from a quick look at the general geological maps of the Peninsula, which show a lithological sequence of Mesozoic or Paleozoic substrata immediately overlain by Holocene alluvium. Likewise, the Pleistocene period was described in terms of unconformity in most local or regional stratigraphical successions of the Peninsula. Recently several different types of Quaternary formation, besides the so-called Holocene alluvium in the valley plain have been found around the Peninsula. They consist of coastal deposits, marine or fluviatile terrace deposits, ancient valley fill deposits or slope deposits. Some parts of the volcanic sediments in Jeju Is. are also known as the Quaternary sequence. Thus the Quaternary deposits in the Peninsula are far more developed than previously known to gelolgists. Moreover the importance of Quaternary research became recently apparent in Korea due to the shortage of raw materials and to the policy of an optimum land-use. Advanced constructions and land reclamation have required more precise engineering parameters of loose materials and an estimation of land stability. This does not imply only the engineering, or the structural properties of the loose material, but at the same time the basic study of the sediments from the stratigraphical and environmental viewpoints has been necessary. In this connection, Quaternary outcrops specially along the coastal fringe of the Peninsula have been mapped, profiled and sampled for sedimentological, clay-mineralogical and palaeomagnetic studies. All these results are compiled for the core of the Quaternary stratigraphy of the Peninsula.

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A Study on the Usefulness of Spot Animation Character of Television Stations (방송사 Spot animation 캐릭터의 유용성에 관한 연구)

  • Youm, Dong-Cheol
    • Cartoon and Animation Studies
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    • s.17
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    • pp.53-67
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    • 2009
  • According to the changes of current regulation of media, the broadcasting environment has been loosened by market power, and came into competitive era for broadcasting industry with new technology of combined broadcasting and communication. To resolve these issues, the broadcasting provides are trying process of new channel brand identity to introduce their channels. The purpose of the research is to analyze Spot animation that has fast access to viewers among channel brand identity factors, review expandability and usage of Spot animation character to plan, manage character that can improve awareness and loyalty. Therefore it will study creation background and production, activities of each character representing KBS and MBC, compare the structure, color, material, expression of Spot animation character and summarize properties. To conclusion, three characters of KBS and MBC failed to apply structured and professional plan and management, only expressed image that each channel pursue on Station ID Spot animation and had issues of not deeply sighting expandability and usefulness as a character. The important factor to improve channel brand value of broadcasting provider is to have differentiated identity, and the core of it is to make image-responsible Station ID to be effective. Therefore, Spot animation and character of Station ID is a very important factor so there must be professional research and structural management from the early planning and production for character that represents the providers.

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Electrical and Optical Properties of the IZTO Thin Film Deposited on PET Substrates with SiO2 Buffer Layer (SiO2 버퍼층을 갖는 PET 기판위에 증착한 IZTO 박막의 전기적 및 광학적 특성)

  • Park, Jong-Chan;Joung, Yang-Hee;Kang, Seong-Jun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.21 no.3
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    • pp.578-584
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    • 2017
  • $SiO_2$ buffer layer (100 nm) has been deposited on PET substrate by electron beam evaporation. And then, IZTO (In-Zn-Sn-O) thin film has been deposited on $SiO_2$/PET substrate with different RF power of 30 to 60 W, working pressure, 1 to 7 mTorr, by RF magnetron sputtering. Structural, electrical and optical properties of IZTO thin film have been analyzed with various RF powers and working pressures. IZTO thin film deposited on the process condition of 50 W and 3 mTorr exhibited the best characteristics, where figure of merit was $4.53{\times}10^{-3}{\Omega}^{-1}$, resistivity, $4.42{\times}10^{-4}{\Omega}-cm$, sheet resistance, $27.63{\Omega}/sq.$, average transmittance (400-800 nm), 81.24%. As a result of AFM, all the IZTO thin film has no defects such as pinhole and crack, and RMS surface roughness was 1.147 nm. Due to these characteristics, IZTO thin film deposited on $SiO_2$/PET structure was found to be a very compatible material that can be applied to the next generation flexible display device.