• 대한원격탐사학회지
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• 제26권2호
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• pp.221-237
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• 2010

해양의 일차생산 측정에 있어 인공위성자료의 활용은 연구선 등을 활용한 기존 조사방법이 갖고 있는 시 공간상의 제한을 많이 개선할 수 있다. 하지만, 황해와 같이 탁한 해역에서의 일차생산 추정은 해수의 광학특성에 의해 여전히 많은 문제점을 가지고 있다. 본 연구에서는 현재 수준에서 가용한 황해의 일차 생산 추정방법들을 비교 평가하였다. 즉, 네 가지의 엽록소-a 추정 알고리듬과 두 가지의 일차생산 추정 알고리듬을 사용하여 각기 다른 조합들이 일차생산 추정에 있어 어떤 차이를 보이는지 알아보았다. 여덟가지 조합에 의해 추정된 황해 중부의 일차생산력은 96.5 에서 $610.2\;gC\;m^{-2}\;yr^{-1}$의 범위값을 가졌다. 최근 한 중 일 연구자들에 의해 공동으로 개발 중인 새로운 엽록소 알고리듬은 탁한 해역에서 표준알고리듬이 잘 맞지 않는 문제를 일부 해결했으나 여전히 해결해야 할 문제를 남겼다. 실측 광합성 매개변수를 새로 적용한 일차생산 추정 알고리듬 또한 개선이 필요하다.

• 대한소아치과학회지
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• 제25권2호
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• pp.383-399
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• 1998

Tooth development is usually described in four stages such as bud stage, cap stage, bell stage and crown stage. Exact time of appearance of tooth primordia is different among reports, and up to now there is no timetable regarding initial tooth development. To understand the congenital malformations and other disorders of the orofacial region, there is a need to establish a standard timetable on early tooth development. Till now, studies on the tooth development were mainly on later fetuses, and only few reports on early stage. Also, there were no reports on the time when bud stage turns to cap stage, and cap stage to bell stage. In this study, external morphology of face and the early development of the tooth, and transition of bud stage to cap stage, cap stage to bell stage were studied using 27 staged human embryos and 9 serially sectioned human fetuses. The results are as follows: 1. Mandibular region was formed by union of both mandibular arch at stage 15, and maxillary region by union of maxillary arch, medial nasal prominence, and intermaxillary segment at stage 19. 2. Ectodermal thickening which represents the primordia of tooth appeared in mandibular region at stage 13, and maxillary region at stage 15. 3. Bud stage began from mandibular primary central incisor at stage 17, and maxillary primary central incisor at stage 18. And the sequence of appearance was in the mandibular primary lateral incisor at stage 19, maxillary primary lateral incisor at stage 20, mandibular primary canine at stage 22, maxillary primary canine and primary first molar at stage 23, madibular primary first molar and maxillary primary second molar at 9th week, and mandibular primary second molar at 10th week of development. 4. Cap stage began from the primary anterior teeth at 9th week, and primary second molar still had the characteristics of cap stage at 12th week of development. 5. Transition to bell stage started from the primary anterior teeth at 12th week, and primary second molar started at 16th week of development. 6. Trnasition to crown stage started from primary anterior teeth at 16th week, and primary second molar at 26th week of development.

• 분석과학
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• 제30권5호
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• pp.287-294
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• 2017

천연가스는 산업의 발전으로 인하여 수요가 계속 증가하고 있어 도입물량 부족 현상이 일어나 수급이 점차 불안정해질 것으로 예상된다. 액화천연가스 외에 파이프라인 천연가스 및 대체 천연가스등 다양한 형태의 가스 도입과 개발로 수요를 충당해야 할 필요성이 있다. 도입된 PNG의 성분과 농도를 정확하게 측정해야 한다. 이에 따른 천연가스 내에 있는 미량 성분인 탄화수소류($C_6-C_{10}$)의 정확한 측정이 요구되어 표준가스의 개발이 필수적이다. 이 연구에서 개발한 일차 표준물질에 대한 조성과 농도는 $10-30{\mu}mol/mol$의 헥산, 헵탄, 옥탄, 노난, 데칸이며 바탕가스는 메탄이다. 탄화수소류($C_6-C_{10}$)의 표준가스 제조는 각 성분 원료가스에 대한 순도분석이 완료된 가스를 ISO 6142에 근거하여 소급성이 있는 중량법으로 알루미늄 실린더에 제조하였다. 제조된 표준가스는 분석기로 표준가스간의 제조일치성, 실린더의 흡착성, 안정성 변화 및 불확도 평가를 하였다. 결과는 알루미늄 실린더에서 내부표면의 흡착 손실이 적고 장기 안정성이 매우 우수하다는 것을 알 수 있었고, 헥산, 헵탄, 옥탄, 노난, 데칸의 농도 $10-30{\mu}mol/mol$ 수준에서 불확도 0.79-1.63 %이내의 표준가스를 개발하였다.

• 대한소아치과학회지
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• 제10권1호
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• pp.25-33
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• 1983

With electron microscope, author studied on the pulp structure of human primary tooth in shedding stage. Non-carious human primary molar teeth were selected for this study. Using standard methods, specimens were sectioned and examined by light and electron microscope, The results were as follows; 1. In coronal pulp, odontoblasts were replaced by multinucleated odontoclasts, which contained a large number of mitochondria of varying shape and vacuoles in cytoplasm. Where odontoclasts were in contact with tooth surface, the characteristic ruffled border and clear zone were observed. 2. Fibrous tissue with plentiful collagen fibers and fibroblasts was observed adjacent to the dentin in the pulp. Fibroblast contained a number of mitochondria and well-developed rough-surfaced endoplasmic reticulum. 3. Inflammatory cells were observed in the pulp and active fibroblasts could be seen between inflammatory cells. In many cases, cervical epithelium proliferated toward absorbed area. 4. Inflammatory cells consisted of a number of lymphocytes, polymorphonuclear leukocytes, plasma cells and macrophages. Macrophage containing lysosomes in digestive state or phagocyting PMN could be seen. 5. In the primary molar of delayed root resorption, odontoblast layer, zone of Weil and cell-rich zone could be seen at roof of pulp chamber and odontoblast in this area cont과ained some lipid droplets.

• 한국학교보건학회지
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• 제16권2호
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• pp.85-95
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• 2003

This paper surveys and researches primary school students' situation of their school life. The purpose of this paper is to propose the basic information of the accident prevention teaching and the safety management in order to avoid accidents to occur beforehand. We selected m primary students out of the six primary schools in Taebaek City at which the nursing students of Kangwon Tourism College practiced school health. We used SPSS Win for analyzing data. We carne up with the general characteristics and percentage using frequency analysis, mean and standard deviation of each item, the mean difference using T-Test, and the different factors using one-way analysis. The results are as follows: 1. The 6th grade students don't practice safety procedures than the 5th grade students during outside the school. The older the student is, the less it practices safety procedures. 2. Boys practice safety procedures better than the girls during inside and outside the school. 3. Hot -tempered students don't practice safety procedures properly. 4. Most of the students who often use the health room of the school have high scores in safety procedures test and as a result, these students practice safety procedures thoroughly. 5. The grade of safety living activity is the highest during gymnastic class. Next is when the students use the stairs when they are going up and clown. Then, the use of science room In the playground is the lowest grade of safety for living activity.

• 한국군사과학기술학회지
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• 제16권3호
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• pp.390-397
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• 2013

Primary-cultured immune cells are widely used in research to elucidate the mechanism of inflammation including chemotaxis, production of reactive oxygen species, cytokine release and antigen presenting. Mice are one of the species of experimental animals commonly used for such studies. Immune cells can be isolated and cultured from various organs such as bone marrow, peritoneal cavity, lung, spleen. For elaborated experimental studies, immune cells should be elicited with inflammatory substances or proliferated in vitro with special media. This paper details methods of obtaining immune cells from various organs of mice and investigating immune mechanism using isolated immune cells. It contains standard protocols of isolating and culturing immune cells from bone marrow, peritoneal cavity and lymphoid organs. It also covers the methods of investigating immune mechanism such as ELISA, western blotting, confocal microscopy and ELISPOT assay. With the works in this study, we established the standardized isolation and analysis methods of primary-cultured immune cells.

• 조명전기설비학회논문지
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• 제27권2호
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• pp.84-94
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• 2013

In case when the existing TRIAC phase controlled dimmer is drove for the LED lighting equipments, there are many problems such as the LED flicker in low phase-angles, the acoustic noise and elements damage by increase of the peak voltage in the input filter capacitor, mulfunction by insufficiency of the TRIAC holding current, and the abnormal oscillation by LC resonant. In this paper, we proposes the single-stage quasi-resonant PSR(Primary Side Regulation) PWM converter, and the design, the simulation and experiment are performed. As a result, it could confirm that the proposed PWM converter is the lighting equipments for LED drive which can alternate the existing 60W class incandescent bulbs and it has the high drive performance of the efficiency 80% and over, the power factor 0.95 and over under the normal voltage 220V. Finally, total harmonic distortion(THD) is gratified with a standard[1] of the lighting equipments and the durability is evaluated as the high reliablilty of 150,000 hours and over.

• 대한두경부종양학회지
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• 제28권1호
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• pp.16-18
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• 2012

원발미상의 경부 전이암의 경우에 있어 동시성 양측 편도암은 드물며, 일부에서는 일측 편도 절제술을 선호하나, 본 증례와 같이 양측 편도암이 발견되는 경우가 있고 또한, 양측 편도절제술이 일측 편도절제술보다 이환율이 크지 않기 때문에 양측 편도 절제술을 시행하는 것이 타당하다고 생각된다.

• 가족자원경영과 정책
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• 제18권2호
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• pp.55-73
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• 2014

The purpose of this study is to examine the level of conspicuous consumption and resource-saving behavior in primary school students, and to discover the factors that influence these behaviors most strongly. The research was conducted in 2011 using a written questionnaires that were completed by 500 primary school students residing in Seoul, South Korea. The data was analyzed using statistical methods, including frequency, percentiles, means, standard deviation, Cronbach's coefficient, ANOVA, and hierarchical multiple linear regression analysis, using SPSS 18.0. As a result of these analyses, the average level of conspicuous consumption was found to be 2.65 relatively rational score. Next, it was shown that the conspicuous consumption of respondents differed significantly based on variables, such as allowances, family income, socialization process in childhood, family cohesion, and parental child rearing method. Finally, the greatest influences on respondent's resource-saving behavior was seen to be the child's socialization process in childhood, family cohesion, parental child rearing method, and conspicuous consumption. These variables must therefore all be considered when teaching primary school students and encouraging them to assume rational resource-saving habits in their daily lives.

• Nuclear Engineering and Technology
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• 제52권12호
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• pp.2901-2909
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• 2020

Thermal creep is a key property of zircaloy cladding. CZ developed by CGN is a new zircaloy used as PWR fuel cladding. This research is devoted to investigating the thermal creep behavior of CZ and build the thermal creep model of CZ. Twenty internal pressure creep tests were conducted, and the ranges of temperature and Tresca stress were 320-430 ℃ and 70-300 MPa, respectively. Real-time creep data were analyzed by separating primary creep and steady-state creep. Based on Soderberg model and creep test data, CZ thermal creep model is derived. As a whole, the mean value and the standard deviation of P/M of CZ saturated primary creep strain are very close to these from steady-state creep rate, however, the predictive effect of primary creep is less satisfactory. Four conditions, where there exists large deviation between predicted values and test data, are 320 ℃ and 300 MPa, 350 ℃ and 190 MPa, 380 ℃ and 160 MPa, 380 ℃ and 190 MPa, respectively. As primary creep was much smaller than steady-state creep in long-time operation, the thermal creep model built can be applied to predict the thermal creep behavior of CZ cladding.