• 한국세라믹학회지
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• 제13권1호
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• pp.25-29
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• 1976

The properties vary with quality of ferric-oxide that is major material of ferrites. In this point of view, a manufacturing method of pure and homogeneous fine ferric oxide is very important. The characters of this study are as follows: 1) Ferric oxide was made from waste pickling liquor of steel. 2) The crude ferric-oxide that is made by roasting the pickling liquor was dissolved in 20% HCI solution and then produced ferric chloride is purified by ethyl ether extraction. 3) The methanol solution of purified ferric chloride was sprayed into the refractory tube with compressed air and propane gas and then ignited leading to the ferric-oxide powder. 4) The produced oxide powder was introduced to the scrubber type vessel throught cooling system in order to collect the powder. 5) Crystalline phase of the powder was identified by X-ray diffraction and particle size, crystalline shape of the powder were investigated by settling method and electron microscope and the effects of concentration of ferric chloride in methanol on grain size were discussed. Results were obtained as fellows: 1) Total impurity in the ferric oxide produced from waste pickling liquor was 3.7%. 2) The solubilityof crude ferric oxide that was made from waste pickling liquor in HCI solution increased with the HCI concentration and reached to saturation range at 15% HCI concentration. 3) Extraction of FeCl3 increased with HCI concentration which is solvent. 4) Alpha ferric oxide obtained was very fine crystalline particles, the mean crystalline grain increased with the concentration of ferric chloride, and mean grain size distributed from 3.5$\mu$(at 0.5mole/l) to 0.5$\mu$(at 0.05mole/l).

• 복식문화연구
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• 제13권5호
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• pp.671-685
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• 2005

The purpose of this study was to develop a new size range and size interval for early adolescent girls. For this purpose, a total of 529 girls aged between 10 and 14 were measured and data were collected from 42 anthropometric measurements and 41 photographic measurements per a person. SAS 8.1 was used in data analysis including means, standard deviations, and frequency analysis. The stature was divided at 5cm intervals as in KS into 9 sizes from the lowest 130cm to the highest 171cm. If waist circumference were divided at the same intervals, the sizes cannot reflect the body growth of adolescent girls at these ages. Thus this study set intervals between sizes irregularly based on the mean of waist circumference by the type of body shape. Based on the results, this study proposed: for Type A - 6 sizes (140A-58, 145A-54, 145A-62, 150A-58, 150A-62, 155A-62); for Type X- 9 sizes (150X-59, 155X-63, 155X-66, 160X-59, 160X-63, 160X-66, 165X-59, 165X-63, 165X-66): and for Type H - 7 sizes (145H-68, 150H-68, 150H-70, 155H-68, 155H-73, 160H-68, 160H-73). For the sizes selected for each type, reference measurements were decided - centering on items necessary for manufacturing clothes. Reference measurements suggested for lower garments 8 items including waist circumference, hip circumference, slacks length and crotch length. The suggested sizes are distributed in a wider range, so they are considered to be helpful for students to find clothes fitting their bodies.

• Composites Research
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• 제26권6호
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• pp.355-362
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• 2013

복합재료 중 가장 많이 사용되는 탄소계 나노복합재의 성능 향상에 대한 연구가 수행되었다. 나노 사이즈의 탄소나노튜브(CNT)와 마이크로 사이즈의 그레파이트(Graphite) 입자를 일정한 형태로 배열하여 나노복합재를 제작하였다. 입자를 배열하기 위하여 전기장을 활용하였다. 일정한 방향 혹은 형태로 배열된 입자는 에폭시 기지 속에서 섬유강화 복합재 처럼 일정한 방향으로 강성의 향상을 나타낸다. 복합재의 구조적 강성이나 물리적 특성은 강화 입자의 배열상태에 따라 매우 달라지게 된다. 본 연구에서는 특히 탄소나노튜브와 그레파이트 강화입자의 전기장 배열에 의해서 만들어진 나노복합재의 강성 및 방사능 차폐특성을 규명하였다. 전기장에 의한 입자의 배열로 만들어진 탄소계 복합재는 구조적 성능뿐만 아니라 물리적인 방사능 차폐에서도 훌륭한 특성을 나타내었다.

• 한국산업보건학회지
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• 제27권3호
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• pp.231-237
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• 2017

Objectives: This study was conducted to determine firefighters' work-related accident rate and investigate the factors affecting their on-site safety. Methods: We developed a web-based self-reported questionnaire designed to inquire into firefighters' work-related accident experience and the factors (4M; Man, Machine, Media, Management) affecting firefighters' on-site safety. We distributed questionnaires to all members of firefighting organizations in South Korea by e-mail and 9,149 were returned, resulting in a response rate of 23.1%. Results: Fifteen point seven percent of the respondents reported work-related injuries within the past one year, and 35.1% answered that current accident investigation reports are not helpful for preventing the same accident from recurring. Among the 4M factors, the one most affecting firefighters' on-site safety in the order of priority is the Man factor, followed by Machine, Media, and Management. However, the results from detailed sub-categorical factors showed some differences. 'Lack of human resources', one of the Management factors, was the most influential (70.3%), followed by 'worn-out equipment' under the Machine factor (67.2%). The viewpoint of elements of the Man factor including 'forgetting instructions' and 'fatigue and illness' were significantly different according to firefighters' rank. The higher the firefighter's rank, the more they answered 'forgetting instructions,' while the opposite was the case for 'fatigue and disease'. Conclusions: The present firefighters' accident investigation report needs to be improved, and the 4M method could prove very useful. In addition, it is necessary to set up a proper firefighters' accident investigation and prevention system.

• 대한치과보철학회지
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• 제55권1호
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• pp.79-87
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• 2017

전치부 개방 교합은 다양한 원인이 복합적으로 작용하고, 진단에 따라 효과적인 치료 계획과 적절한 유지 방법을 선택할 수 있다. 대부분의 경우 교정과 악교정 수술을 통해 안정적인 교합을 얻고, 기능과 심미를 회복한다. 하지만 전체 치열에서 심한 우식증이 있는 경우 광범위한 수복이 필요하게 되므로, 보철 수복을 통해서도 교합을 재형성할 수 있다. 본 증례는 심한 우식을 동반한 골격성 전치부 개방 교합 환자에서 안모 분석 및 진단 납형으로부터 가장 효과적인 치료로 전악 보철 수복을 선택하였다. 교합력을 균등하게 분산하고 심미적인 임시 수복물을 제작하였고, 악간 관계 평가, 혀 등 연조직의 적응, 입술과의 조화를 관찰하고 수정하였다. 충분한 기간 동안 사용한 임시 수복물을 CAD/CAM (Computer-aided design/computer-aided manufacturing)을 이용하여 단일구조 지르코니아 최종 보철물로 이행하였고, 치료 종결 후 3개월 간 주기적으로 관찰하였을 때 만족스러운 결과를 얻었다.

• 한국재료학회지
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• 제27권7호
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• pp.374-380
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• 2017

Properties of coatings produced by warm spray were investigated in order to utilize this technique as a repair method for Al tire molds. $Al-(0-10%)Al_2O_3$ composite powder was sprayed on Al substrate by warm spraying, and the microstructure and mechanical properties of the composite coating layer were investigated. For comparative study, the properties of the coating produced by plasma spray, which is a relatively high-temperature spraying process, were also investigated. The composite coating layers produced by the two spray techniques exhibited significantly different morphology, perhaps due to their different process temperatures and velocities of particles. Whereas the $Al_2O_3$ particles in the warm sprayed coating layer maintained their initial shape before the spray, flattened and irregular shape $Al_2O_3$ particles were distributed in the plasma sprayed coating layer. The coating layer produced by warm spray showed significantly higher adhesive strength compared to that produced by plasma spray. Hardness was also higher in the warm sprayed coating layer compared to the plasma sprayed one. Moreover, with increasing the fraction of $Al_2O_3$, hardness gradually increased in both spray coating processes. In conclusion, an $Al-Al_2O_3$ composite coating layer with good mechanical properties was successfully produced by warm spray.

• Nuclear Engineering and Technology
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• 제42권5호
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• pp.568-575
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• 2010

Flow Accelerated Corrosion is an active degradation mechanism of CANDU feeder. The tight bend downstream to Gray loc weld connection, close to reactor face, suffers significant wall thinning by FAC. Extensive in-service inspection of feeder wall thinning is very difficult because of the intense radiation field, complex geometry, and space restrictions. Development of a knowledge-based inspection program is important in order to guarantee that adequate wall thickness is maintained throughout the whole life of feeder. Research results and plant experiences are reviewed, and the plant inspection databases from Wolsong Units One to Four are analyzed in order to support developing such a knowledge-based inspection program. The initial thickness before wall thinning is highly non-uniform because of bending during manufacturing stage, and the thinning rate is non-uniform because of the mass transfer coefficient distributed non-uniformly depending on local hydraulics. It is obvious that the knowledge-based feeder inspection program should focus on both fastest thinning locations and thinnest locations. The feeder wall thinning rate is found to be correlated proportionately with QV of each channel. A statistical model is proposed to assess the remaining life of each feeder using the QV correlation and the measured thicknesses. W-1 feeder suffered significant thinning so that the shortest remaining life barely exceeded one year at the end of operation before replacement. W-2 feeder showed far slower thinning than W-1 feeder despite the faster coolant flow. It is believed that slower thinning in W-2 is because of higher chromium content in the carbon steel feeder material. The average Cr content of W-2 feeder is 0.051%, while that value is 0.02% for W-1 feeder. It is to be noted that FAC is reduced substantially even though the Cr content of W-2 feeder is still very low.

• 산업경영시스템학회지
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• 제35권3호
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• pp.87-94
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• 2012

This study investigates the relationship among locus of control, organizational justice, and job satisfaction. First, this study examines the conceptual structures of organizational justice through field study. Second, organizational justice influences job satisfaction. Third, locus of control influences organizational justice. Literature review identified four factors of organizational justice - distributive, procedural, interpersonal, and informational justice. These identified determinants are expected to have significant relationships with locus of control and job satisfaction. Questionnaires were distributed to 500 members of a manufacturing companies. Among returned questionnaires, 357 samples were used for empirical study. Structural equation analyses based on PLS (partial least square) method were employed to test the hypotheses and the model. The overall adequacy of fit was found to be acceptable. Confirmatory factor analyses supported a 4-factor structure of organizational justice. Distributive, procedural, interpersonal, and informational justice had significant positive effects on job satisfaction. In addition, the effects of locus of control had significant positive effects on organizational justice factors. The results of this study suggest that interpersonal and informational justice should be regarded as important factors of organizational justice to analyze the relationships between locus of control and job satisfaction as well as the relationships among the justice constructs.

• Archives of Pharmacal Research
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• 제29권2호
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• pp.123-130
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• 2006

1,4-Naphthoquinones are widely distributed in nature and many clinically important antitumor drugs containing a quinone moiety, such as anthracyclines, mitoxantrones and saintopin, show excellent anticancer activity. In this study, 2- or 6-substituted 5,8-dimethoxy-1,4-naphthoquinone (DMNQ) and 5,8-dihydroxy-1,4-naphthoquinone (DHNQ) derivatives were synthesized, and their cytotoxic activity against L1210 and P388 cancer cells was examined. Their antitumor activity was also assessed in mice bearing S-180 cells in the peritoneal cavity. In comparison with the DMNQ derivatives, the DHNQ derivatives exhibited more potent bioactivities than the DMNQ derivatives against both L1210 and P388 cells in vitro and S-180 cells in vivo. The $ED_{50}$ values of the DHNQ derivatives against P388 cells were in the range of 0.18-1.81 ${\mu}g/mL$ whereas those of the DMNQ derivatives were in the range of 0.26-40.41 ${\mu}g/mL$. The T/C ($\%$) values of the DHNQ derivatives, 8, 17, 18, 19, and 20, were found to be comparable to or even better than that of adriamycin. It was also observed that the 2-substituted derivatives (8, 19, 20) showed better antitumor activity than the 6-substituted derivatives (7, 17, 18) in the mice bearing S-180 cells in the peritoneal cavity.

• 한국항만경제학회지
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• 제27권2호
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• pp.59-84
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• 2011

연구의 목적은 부산시 물류창고업의 공간분포와 연계의 특성을 파악하고 우리나라 항만 배후단지의 물류창고업에 대한 정책적 시사점을 제공하는 것이다. 본 연구에서는 부산시에 입지하는 물류창고업체를 대상으로 설문조사를 하였다. 설문자료에 기초하여 부산시 물류창고업을 업종, 규모, 조직형태로 구분하고 GIS를 이용한 점 패턴 분석과 근접성 분석을 하였다. 부산시 물류창고업은 영세한 단독사업체에서 탈피하여 본사와 지사 등의 조직을 가진 중 대규모의 업체로 변화하고 있다. 이들 업체들은 북항, 남항 및 감천항 등의 배후지역, 신평 장림공단 및 사상공업지역에서 공간적 집적을 이루며 분포한다. 부산시 물류창고 업은 고객인 제조업체에게 보관 서비스뿐만 아니라 다양한 서비스를 제공하기 위해 동일 산업인 물류업의 다른 업종과 연계를 형성한다. 연계는 공간적으로 근접한 국지적 범위에서 대부분 형성되어 집적이익을 발생시켰으며 집적이익은 국지적 범위 내 물류창고업의 효율성으로 전환되어 연계의 공간적 범위를 확대시키는 것으로 나타났다.