• 제목/요약/키워드: Concentrated growth factors

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확장 유한 요소법(XFEM) J-적분을 이용한 노후 순시선의 균열 성장 수명 예측 (Prediction of Crack Growth Lives of an Aged Korean Coast Guard Patrol Ship based on Extended Finite Element Method(XFEM) J-Integral)

  • 김창식;리춘보;김영훈;정준모
    • 대한조선학회논문집
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    • 제54권4호
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    • pp.335-343
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    • 2017
  • The Newman-Raju formula and contour integral-based finite element analyses(FEAs) have been widely used to assess crack growth rates and residual lives at crack locations in ships or offshore structures, but the Newman-Raju formula is known to be less accurate for the complicated weld details and the conventional FEA-based contour integral approach needs concentrated efforts to construct FEA models. Recently, an extended finite element method(XFEM) has been proposed to reduce those modeling efforts with reliable accuracy. Stress intensity factors(SIFs) from the approaches such as the Newman-Raju formula, conventional FEA-based J-integral, and XFEM-based J-integral were compared for an infinitely long plate with a propagating elliptic crack. It was concluded that the XFEM approach was far reliable in terms of prediction ability of SIFs. Assuming a 25 year-aged coast guard patrol ship had the prescribed cracks at the bracket toes attached to longitudinal stiffeners in way of deck and bottom, SIFs were derived based on the three approaches. To obtain axial tension loads acting on the longitudinal stiffeners, long term hull girder bending moments were assumed to obey Weibull distribution of which two parameters were decided from a reference (DNV, 2014). For the complicated weld details, it was concluded that the XFEM approach could cost-effectively and accurately estimate the crack growth rates and residual lives of ship structures.

인삼재배 분야의 과거 20년 연구 (Research on Ginseng Production During the Past 20 years)

  • 밝훈
    • Journal of Ginseng Research
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    • 제20권4호
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    • pp.472-500
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    • 1996
  • Researches on mineral nutrition, physiology and phyrsiological diseases, . cultivaction methods. brceding. pest control quality management and extension during 1976-1995 in Korea were reviewed Review in brceding and pest control was restricted to the researches directely related to cultivaction. Mineral nulrient up take. partion and varicos factors such as top dreasing. Light intersity etc. and interrelationship between minerals were investigated. Top dressing was not effective due to low minera1 requorement Physiological characteristics on tempelature light and water were well elucidated and applied to assess traditional cultivation method and its inovation. Photosyrnthetic pigments. light harvest proteins and activity of related enzymes were studied. In nitrogen metabolism arginine, praline, ammonium, threonine appeared to have important role in re growth of shoot Saponin metabolism was studied in relation to growth and new ginsenosides were found but physiological role of saponin was not clearly elucidated yet Endogenous growth regulators were reported and various erogenous growth regulators were studied for growth stimulation. short stem and seed pruning etc. Various physiological diseases were investigated for cause and control measures were established. Water culture was little studied Forest culture was studied but not retched the recommendable stage Drip irrigation straw mulching. seasonal shading and soil preparation method including soil fertility adjustment were established for practical application. Shading materials completely changed to polyethylene net and materials of polymers The research on ginseng cultivation in paddy field opened the way to establish the permanent ginseng cultivation plantation Ginseng harvester and seeder were developed in the late 1950s. Transplanted and many other machines were developed in the early 1990s. In ginseng breeding only pure line selection was of practical significance several verities were at the stage of seed propagation at ginseng plantations. Mutation breeding (${\gamma}$-ray. X-ray chemicals) was not successful. The research on plantlet formation through tissue culture was a little progressed but still far behind to vegetative propagation. Disease control research was concentrated in the isolation and identification of pathogans. their ecological charactelistics and biological control and soil humigation. Potato root rot nematodes was found and control method was established. Insect and small animal control research was greatly progresses in identification, ecological investigation, and ecological and physical control. Weed control was less important due to the development of mulching method of ridge and ditch. Quality factors of raw ginseng in relation to red ginseng process were extensively studied. Traditional quality measures were elucidated in accordance with modern analytical chemistry resulting in the importance of peptides in the centrat part rather than ginsenosides For large root production growth promoting rootzone micrcorganisms (PGPRM) were isolated and active compounds were identified. Field test on PGPRM was on going. Varictus methods formality improvement through cultivation were developed. Management research of ginseng production was rare Extension was active throuch official and private organizations and through workshop for the extension specialists, and direct lectures to grower's. Extension services made the researcher to understand the existing problems at grower's fields. Research environment for ginseng production was in prime time only for three years when Korea Ginseng Research Institute was established then gradually aggravated.

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초등학생의 간식 구매실태 및 관련 생태학적 요인분석 (A Study of the Frequency of Food Purchase for Snacking and Its Related Ecological Factors on Elementary School Children)

  • 강석아;이정원;김경은;구재옥;박동연
    • 대한지역사회영양학회지
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    • 제9권4호
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    • pp.453-463
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    • 2004
  • In order to investigate food purchase frequency of elementary school children and its related ecological factors, 431 4th, 5th and 6th grade elementary school children and their mothers, living in Seoul and Daejon, small city and rural area of Chungnam Province, were participated in this study. The subjects and their parents were surveyed by a self-recording questionnaire about food purchase frequency and some ecological factors. Average height and weight of the subjects by gender and grade were similar to or a little bit more than the 1998 Korean Growth Standard. According to relative body weight, 30.6% and 10.8% of the subjects belonged to under-weight and obesity categories, respectively. Of the subjects, 46.9% used PC telecommunication or internet, 53.8% of them used it for less than an hour per day, and 46.4% watched TV for 2 to 4 hours a day. About 42% of the subjects spent 500 Won or less daily to buy snacks. A half of the subjects took snacks once a day because of hunger. Mothers' nutrition knowledge score was averagely 8.16 out of 13 full score and the average attitude score was 43.22 out of 50 full score. Foods purchased more than once a week were milk and yoghurt, cookies, ice-cream, ramyun, and gum in order. Family income, parents' education level, mothers' nutrition knowledge and food attitude score, students' snacking frequency and TV watching time showed significant correlations with purchase frequencies of some individual food items. In conclusion, the elementary school children considered taste most important rather than nutrition in buying snacks and most frequently bought carbohydrate foods and concentrated sugars except milk. Ecological factors such as mothers' nutritional knowledge and food attitude, TV watching time and snacking frequency had influenced the children's food purchase frequency. Accordingly, it is necessary to educate both children and their mothers about good food purchase and the importance of snacking.

고성능 PRO 모듈 개발 및 운전조건이 모듈 성능에 미치는 영향 (The development of high-performance PRO module and effects of operating condition on the performance of PRO module)

  • 한만재;심연주;이종화
    • 상하수도학회지
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    • 제31권4호
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    • pp.303-310
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    • 2017
  • Pressure retarded osmosis(PRO) has attracted much attention as potential technology to reduce the overall energy consumption for reverse osmosis(RO) desalination. The RO/PRO hybrid process is considered as the most logical next step for future desalination. The PRO process aims to harness the osmotic energy difference of two aqueous solutions separated by a semipermeable membrane. By using the concentrated water(RO brine) discharged from existing RO plants, the PRO process can effectively exploit a greater salinity gradient to reduce the energy cost of processing concentrated water. However, in order to use RO brine as the draw solution, PRO membrane must have high water flux and enough mechanical strength to withstand the high operational pressure. This study investigates the development of a thin film composite PRO membrane and spiral wound module for high power density. Also, the influence of membrane backing layer on the overall power density was studied using the characteristic factors of PRO membranes. Finally, the performance test of an 8-inch spiral wound module was carried out under various operating conditions(i.e. hydraulic pressure, flow rate, temperature). As the flow rate and temperature increased under the same hydraulic pressure, the PRO performance increased due to the growth of water permeability coefficient and osmotic pressure. For a high performance PRO system, in order to optimize the operating conditions, it is highly recommended that the flow pressure be minimized while the flow rate is maintained at a high level.

신해양질서의 어업관리체계와 TAC 제도 도입에 관한 연구 (A Study on the Korean Fishery Management System and TAC System Implementation on Issues of the New Ocean Regime)

  • 이상고
    • 수산경영론집
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    • 제30권1호
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    • pp.1-29
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    • 1999
  • When the international fisheries order changes following the UN Law of the Sea, the new regional fisheries order is forming among East North Asian states and era of Economic Zones is really coming. In those changes of foreign and domestic fisheries environment, to maintain sustainable growth of the industry in 21st century the North East Asian states plot adjustments to fisheries management, such as introduction of the TAC system and others. The TAC seems to be an appropriate systematic response especially because traditional functions of fisheries management have already demonstrated their limits in regards to fisheries sustainable development. Introduction of the TAC to the North East Asian fisheries not only resolves the inability of traditional fisheries management to develop the industry consequently, but also strengthens the EEZ and existing marine management systems. However, the TAC was born by thewestern industrial mentality, still contains persistent mistakes and is difficult to change. Therefore, its introduction to and implication in North East Asian region might cause numerous problems. From this point of view, introduction of the TAC system will disregard peculiarities of North East Asian fisheries, so main efforts should be concentrated on improving the functions of existing system via consecutive step-by-step approach. In addition, the TAC should be grafted into the existing fisheries system through cooperative management system, creating stable systematic ground and considering scientific and fisheries motives. Especially, TAC system, unlike the traditional fisheries' management system, is scientific, being systematically developed one, and needs to be gradually installed, considering its systematic character. Therefore, the TAC should better be introduced by systematic and scientific approaches, paying more attention to strengthening the existing fisheries system, but not immediately and in the form it is right now. Concluding, introduction of the TAC can not be made considering the outward factors deriving from the UN Law of the Sea without corrections.'h overcome limitations and ineffectiveness of traditional fisheries, most efforts should be concentrated on basic revision of 21st centuries' fisheries and strengthening the functions of traditional fisheries aimed to develop the leading business of marine industries.

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부유 및 부착성장 질화균에 미치는 구리 독성의 영향 (Effect of Copper toxicant on Suspended and Attached Growth Nitrifying Bacteria)

  • 김금용;백주헌;이상일
    • 대한환경공학회지
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    • 제31권10호
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    • pp.855-864
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    • 2009
  • 본 연구에서는 질산화 반응이 활발히 진행되고 있는 기존 하수처리장 슬러지를 이용하여 3개월 이상 농축 배양한 후에 부착 및 부유성장 상태로 적응시킨 질화균을 이용하여 독성물질에 대한 영향을 조사하였다. 본 실험의 목적은 부유 및 부착성장 질화균을 이용하여 이들의 비표면적에 따른 독성물질의 영향을 상호비교하기 위한 것이다. 이를 위하여 부유 및 부착상태의 농축 질화균의 비표면적을 다르게 하여 각각에 대한 독성물질의 영향을 조사하였다. 연구 결과 부착성장 질화균 및 부유성장 질화균의 경우 비표면적이 클수록 독성에 대한 영향을 더 많이 받는 것으로 나타났다. 부착상태와 탈착상태의 질화균을 사용한 실험에서, 독성물질에 대한 영향은 탈착상태보다 부착상태에서 독성의 영향을 적게 받았으며, Nitrosomonas의 경우에는 1.12배, Nitrobacter의 경우에는 1.09배 독성의 영향을 적게 받았다. 부유성장 질화균을 사용한 경우에는 분쇄 전보다 분쇄 후에 독성의 영향을 더 크게 받았으며, Nitrosomonas의 경우에 1.46배, Nitrobacter의 경우에 1.35배 독성의 영향을 적게 받았다. 또한, 기질에 아질산염을 주입하지 않고 실험한 결과에서도 유사한 결과를 얻었다. 부착상태와 탈착상태의 질화균을 사용한 실험에서, 독성물질에 대한 영향은 탈착상태보다 부착상태에서 독성의 영향을 적게 받았으며, Nitrosomonas의 경우에는 1.83배, Nitrobacter의 경우에는 1.78배 독성의 영향을 적게 받았다. 부유성장 질화균을 사용한 경우에는 분쇄 전보다 분쇄 후에 독성의 영향을 더 크게 받았으며, Nitrosomonas의 경우에 1.27배, Nitrobacter의 경우에 1.32배 독성의 영향을 적게 받았다.

위기관리관점에서 대학의 안전관리 법제 방안 (A Legislative Device for the University's Safety Management System in Terms of Crisis Management Perspective)

  • 배대식
    • 한국콘텐츠학회논문지
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    • 제8권4호
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    • pp.183-196
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    • 2008
  • 이 연구에서는 대학영역에서의 안전관리 문제에 초점을 두고 대학의 양적 발전과 성장에 따른 위험 사회적 요소와 특성을 탐구하고, 안전관리에 관련된 법제문제를 연구하고자 한다. 대학캠퍼스는 인적자원과 물적자원, 지식정보자원이 집중되어 있는 사회의 축소판으로써 이러한 자원들을 위협하는 다양한 위험요인이 압축적으로 잠재되어 있는 영역이다. 그럼에도 불구하고, 지금까지 위험불감증과 무사안일주의로 인하여 캠퍼스내에 누적된 위험요소들을 인식하지 못하고 대학은 안전관리의 사각지대에 방치되고 있다. 최근에는 대학 연구실 안전사고 뿐만 아니라 사회양극화 현상의 심화, 스트레스와 장래에 대한 불안감, 정신질환의 증가로 인한 무동기범죄와 마약류 범죄, 사이버범죄 등 신종범죄에 대하여 체계적이고 종합적인 대책이 절실히 요구되고 있다. 따라서 대학에서 각종 안전사고와 재난을 예방하고 자원을 보호할 수 있도록 위기관리 관점에서 안전관리시스템을 구축할 수 있는 법제방안을 제시하고자 한다.

보편적 소통 가능한 학교 공공 디자인의 공공성에 관한 연구 - 도시 재생적 측면을 중심으로 - (A Study on the Publicness in Public Design with Schools for Universal Communication - Focused on aspects of Urban Regeneration -)

  • 이용환
    • 교육녹색환경연구
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    • 제13권1호
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    • pp.58-68
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    • 2014
  • Recently, multiple metropolitan counties and local authorities have been actively working on improving their local existence with various methods and strategies. Such change cannot be observed when local authorities were chosen by the government. Also, the public administration has recently emphasized important factors of public design which seeks better lifestyle and outward beauty from quantitative growth and policy of strongly considering outward form due to the compressive modernization. Public design intends to complete aesthetic factor and improve the quality of life as the efficiency as the value of public administration. The purpose of this study is to discuss how public school has been evolved as public space and how to create local user-centered interaction. The study retrieve the communication which the essential publicness in the school public design and the self-management which is the original value in terms of sociology. The method in which the characters of the public design of the publicness have been changed will be concentrated on in public area. In addition, the study has been focused on the efforts of the reflection of the development in public design are the challenges for the aim of the design of the publicness.

미더덕 추출액을 섭취한 무지개 송어 혈액성상의 변화 (The Change in Hematological Factors of Ascidian (Styela clava) Extract Diets Fed Rainbow Trout (Oncorhynchus mykiss).)

  • 정우철;이정태;;강석중;최병대
    • 생명과학회지
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    • 제17권9호통권89호
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    • pp.1244-1247
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    • 2007
  • Effects of muscle fluid concentrates from Styela clava on fish diets were investigated in rainbow trout(Oncorhynchus mykiss). Fish were fed on one of the isonitrogenous(48%) and isolipic(20%) feed containing 5 to 20% of muscle fluid concentrates for 8 weeks. Hematological parameters such as hemoglobin, hematocrit, albumin, glucose, total bililubin, triglyceride and glutamic pyruvate transaminase of the rainbow trout which were fed on the diets varied, but no specific trend became apparent. However, glutamic oxaloacetic transaminase value was significantly higher than that of normal fishes. Therefore, concentrated ascidian fluid which is normally discarded, can be combined with commercial diets for the normal growth of rainbow trout.

산업화 과정에서 나타나는 가구디자인 변화 요인 연구 - 1960년대에서 2010년대까지 한국 가구산업을 중심으로 - (A Study of Furniture Design Changes Factors Appearing in the Industrialization Process - Focused on the Korea Furniture Industry, 1960~2010 Year -)

  • 김경수
    • 한국가구학회지
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    • 제27권4호
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    • pp.399-411
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    • 2016
  • Korea Furniture design development process is repeated a number of changes by the change of residence and type of market demand derived from the process of industrialization. The modernization process of industrialization advances by large-scale population moves to the city to urbanization proceeds rapidly. Housing problems are concentrated in cities and sparked the furniture industry, furniture design by changes in marketing concepts that appear in the industrialization phase, growth must necessarily accommodate the needs of consumers. Including kitchen furniture, living room furniture and master bedroom furniture has been sensitively adapted changes in the structure of these houses, particularly structural changes Apartments. Starting in the 1990s, jumping over furniture industry has adapted quickly to the market demand, changes in marketing concepts. Furniture industry is growing market share in most of the country, but the entire industry had to undergo a competitive marketing overheating due to excessive supply in excess of market demand since the mid-1990s. Changes in furniture design in this process was the change in furniture design more than the change of the residential structure. The study industrial development and marketing concepts are changing to construct a model to track the changes varied styles and time changes affect whether the main furniture design.