• 제목/요약/키워드: Concentration History

검색결과 284건 처리시간 0.031초

하이드레이트 함유 퇴적물의 역학적 성질 및 지구물리 특성 (Mechanical and Electrical Properties of Hydrate-bearing Sediments)

  • 이주용
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2007년도 추계학술대회 논문집
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    • pp.594-596
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    • 2007
  • Using an oedometer cell instrumented to measure the evolution of electromagnetic properties, small strain stiffness, and temperature, we conducted consolidation tests on four types of sediments. The tested specimens include sediments with different gas hydrate saturation at four stages of loading. The test results show that the electromagnetic and mechanical properties of hydrate-bearing marine sediments are governed by the vertical effective stress, stress history, porosity, hydrate saturation, fabric, ionic concentration of the pore fluid, and temperature. The results also show that permittivity and electrical conductivity data can be combined to estimate hydrate volume fraction in laboratory sediments, methodology that might eventually be extended for estimation of hydrate concentrations in field settings.

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Changes of Distribution Coefficients of Cu, Cr, and As in Different Soil Matrix in a Laboratory Scale

  • Kang, Sung-Mo;Ra, Jong-Bum;Kim, Suk-Kuwon
    • Journal of the Korean Wood Science and Technology
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    • 제37권2호
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    • pp.137-140
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    • 2009
  • Chromated copper arsenate (CCA), a long history of successful preservative, have raised environmental concerns. Adsorption characteristics of domestic soils for chromium, copper, and arsenic were assessed by measuring distribution coefficient ($K_d$) values of these metal components in a laboratory scale. The results revealed that $K_d$ values were higher in chromium, followed by arsenic and copper in soil matrix. Different soil matrixes resulted in varying mobilities of CCA components. The values of $K_d$ for all three metals increased with organic matter contents. The results suggest that the mobility of metal components may be very limited to the surface area adjacent to CCA-treated wood due to their fairly large distribution coefficient ($K_d$). However, the metal components would be persistent and accumulated in the soil, resulting in high chemical concentration in service area of treated wood.

미래지향적인 관점에서 본 치아우식증 예방과 음용수 불소화 (Prospective on Prevention of Dental Caries and Water Fluoridation)

  • 박기철;김완규
    • 대한치과의사협회지
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    • 제38권1호통권368호
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    • pp.86-93
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    • 2000
  • Water fluoridation in conjunstion with wide use of fluoride dentifrices has been a major factor responsible for the decline in dental caries during the second half of the 20th century throughout the world. The history of water of water fluoridation is a classic public health program leading to epidemiologic investigation and community-based public health dentistry program. Although other fluoride-containing products are available, water fluoridation remains as the most safe and cost-effective method of delivering fluoride to omost communities. regardless of age. educational attainment. or income levels,. This review deals with pros and cons of water fluoridation and prospective analysis of state-of-the-art on issues related to the use of fluoride. An "optimal" fluoride concentration of 0.7-1.2 ppm has been recommended for preventing dental caries with a minimal dental fluorosis and no systemic health consequences.

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디젤기관차 대차프레임의 하중이력 측정 및 피로수명평가 (The Fatigue life evaluation and load history measurement for Bogie frame of locomotive)

  • 서정원;권석진;함영삼;권성태
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2008년도 추계학술대회A
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    • pp.378-383
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    • 2008
  • Bogie frame of the locomotive is an important structural member for the support of vehicle loading. A lot of study has been carried out for the prediction of the structural integrity of the bogie frame in experimental and theoretical domains. The objective of this paper is to estimate the structural integrity of the bogie frame. Strength analysis has been performed by finite element analysis. From these analysis, stress concentration areas were investigated. For evaluation of the loading conditions, dynamic stress were measured by using strain gage. It has been found that the stress and strain due to the applied loads were multi-axial condition according to the location of strain gage. The fatigue strength evaluations of the bogie frame are performed to investigate the effect of the multi-axial load through the employment of the critical plane approach.

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P-Δ 효과에 의한 철골 라멘 하부층 변형집중현상 억제를 위한 SM570TMC 고강도강 혼용 사용 설계제안 (Proposal of the Structure Design using SM570TMC for Preventing Deformation Concentration by P-Δ Effect on Lower Story in Steel Ramen)

  • 김문정
    • 복합신소재구조학회 논문집
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    • 제3권3호
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    • pp.31-37
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    • 2012
  • Under the huge seismic loads, there are too many risks about which high-rise buildings lost their lateral stiffness caused by plasticity on frame members. Because of earthquake is important cause to bring the collapes countinue to human's life, many reports examined these phenomenons in various angles. And some of them reported the high possibility about building collapse by deformation concentrations under huge earthquakes. For preventing these phenomenons, researchers suggest some items-such as adding damping devices or strengthen their ductility or stifness. This report suggests choose the method of strengthen building stiffness and suggests the alternative designs using high strength steel-SM570TMC, and provides the results of time-history analysis about the alternative designs for investigation.

소아 빈혈의 감별진단 및 치료 (Differential Diagnosis and Treatment of Anemia in Children)

  • 임영탁
    • Clinical and Experimental Pediatrics
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    • 제48권2호
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    • pp.121-125
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    • 2005
  • Anemia can be defined as a reduction in blood hemoglobin concentration or red cell mass relative to age matched normal values. Clinical presentation may range from obviously pale and lethargy to an incidental finding during screening of an otherwise well appearing child. The differential diagnosis of anemia in each instance is broad with numerous possible etiologies. A careful history and physical examination as well as complete blood count, peripheral blood smear and additional laboratory tests are necessary in defining underlying cause of the anemia and guide in further treatment plans. In addition, Iron deficiency anemia and anemia of inflammation are common causes of mild to moderate anemia in children, but most pediatricians have some confusions to differentiate these two entities.

Acquired myasthenia gravis in a domestic shorthair cat with cranial mediastinal mass

  • Song, Doo-Won;Kang, Min-Hee;Park, Hee-Myung
    • 대한수의학회지
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    • 제56권2호
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    • pp.121-123
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    • 2016
  • A 7-year-old castrated male domestic short-hair cat presented with anorexia, constipation, depression, and voice alteration. Physical and neurological examinations revealed hyperthermia ($40.5^{\circ}C$), ventroflexion of the neck, reduced responses to external stimuli, generalized muscle weakness, and exercise intolerance. Thoracic radiographs revealed the presence of a cranial mediastinal mass. The history, clinical signs, and other examination results were compatible with acquired myasthenia gravis (MG). Acetylcholine receptor (AChR) antibody titers were determined to confirm MG and the serum AChR antibody concentration was 1.24 nmol/L (reference interval, < 0.3 nmol/L). This is the first diagnosis of acquired MG in a cat in Korea.

자동차용 가솔린 기관의 정상연소 및 이상연소에 관한 연구 (A Study on the Normal Combustion and Abnormal Combustion in Automotive S.I.Engine (Knocking Phenomena in Quiscent or Swirl Flow Field))

  • 이경우;등본원;박경석
    • 한국자동차공학회논문집
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    • 제3권6호
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    • pp.250-261
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    • 1995
  • In this study, a rapid compression and expansion machine(RCEM) equipped with a swirl generator was designed and developed, in order to clarify normal and abnormal combustion(knocking phenomena). This RCEM is intended to simulate combustion process in actual automotive S.I.engines, having a high reproducibility in the compression stroke. Flame propagation and autoignition processes associated with normal and abnormal combustion were captured by the high speed schlieren photography. And swirl intensity. equivalence ratio and ignition position were varied to investigate the effect of turbulence, concentration in the unburnt gas region and flame propagation length. The knock intensity, knock mass fraction and knock mass fraction after autoignition were calculated by use of history of measured cylinder pressure.

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기업특성이 물류정보시스템에 미치는 영향에 관한 연구 (The study on the effects of firm′s characteristics on the logistics information system)

  • 이해신
    • 산업경영시스템학회지
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    • 제21권47호
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    • pp.253-266
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    • 1998
  • The purpose of this study was to analyze the difference in logistics information system and indirect effects of logistics performances on the acceptance level of logistics information system. The limitation and recommendation of this study were as follows : First, as the history of logistics introduction in Korean corporations is short, the level of logistics information system sampled in this study is very low. So the findings of this study is hard to represent the general logistics information system situation of in Korea our corporations. Second, the focus of this study is on the manufacturing corporations, so the study on the logistics corporations is required. And the study on the effects of firm's situation(formalization, decentralization, concentration, strategic plans) on the characteristics of logistics information system is needed.

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A Study on the Development of Curriculum Track for Civil Service Librarian

  • Noh, Younghee
    • International Journal of Knowledge Content Development & Technology
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    • 제3권1호
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    • pp.31-63
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    • 2013
  • The goal of this study is to improve the competitiveness of professional librarians in society. To this end, we analyzed domestic and international LIS curriculum, determined demand from field librarians through a survey, carried out job analysis by library types, and developed an operating model for LIS curriculum by synthesizing all of these results. Finally, we suggested a course of study for civil service librarians based on this model. As a result, the six required courses for civil service librarians are: Introduction to Library and Information Science, Information Organization, Information Services (Reference and Information Services), Library Management, Information Retrieval, and Field Work. The four core courses for the civil service concentration are: Collection Development, Information Sources by Subjects, Public Library Management, and Digital Libraries. Suggested electives best suited to this career path include Using Web Resources, Information Literacy, Information Services in Culturally Diverse Communities, Library Marketing, Libraries and Cultural Programs, Reading Guidance, Library History, Small Library Management, Studies in Library Buildings, Library Cooperation, Managing Digital Collections, and Information and Communication in a Digital Age.