• Journal of Preventive Medicine and Public Health
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• v.36 no.4
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• pp.303-313
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• 2003

General information is summarized, that is necessary to introduce a scientific assessment of the human health and exposure issue concerning dioxin and dioxin-like compound. Scientific literatures were reviewed to assess the background exposures to the dioxin-like compounds for normal residents. Epidemiologic studies were also reviewed to assess malignant and nonmalignant sweets of dioxins. In 1997, the International Agency for Research on Cancer classified 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as a human carcinogen, primarily based on occupational cohort studies. The US Environmental Protection Agency made the same decision in it's Draft Dioxin Reassessment. Epidemiologic evidences point to a generalized excess of all cancers, without any pronounced excess at specific sites. Reported non-cancer effects included a range of conditions affecting most systems. Among them, chloracne, elevation in gamma glutamyl transferase(GGT), and alterations in reproductive hormones are related to TCDO, Other adverse outcomes, such as lipid concentrations, diabetes, circulatory and heart diseases, immunologic disorders, neurobehavioral effects, and developmental outcomes require further study before their respective relationships to TCDD can be more definitively assessed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.5
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• pp.2009-2014
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• 2012

It is very important to minimize the die roll height of gear, in order to maximize the shear cutting surface(tooth surface) of fine blanking. In this paper, the fine blanking tool sets were manufactured in order to study the die roll height according to V-ring position and die chamfer shape. They were constituted of the various die inserts and guide plate inserts with different die chamfer shape and different V-ring distance. The fine blanking experiment was conducted with the fine blanking tool sets and the die roll height of the gear samples was measured. It should be noted that die roll height on the fine blanked gear increased with increasing the V-ring distance and die chamfer angle.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.8
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• pp.3301-3306
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• 2012

In LED chip packaging, die bonding is a very important process which fixes the LED chip on the lead frame to provide enough strength for the next process. Conventional pick-up device of the die bonder is simply operated by up and down motion of a collet and an ejector pin. However, this method may cause undesired problems such as position misalignment and/or severe die damage when the pick-up device reaches the die. In this study, to minimize the position alignment error and die damage, a die bonder is developed by adopting a new pick-up head for precise alignment and high speed feeding. To evaluate structural stability of the designed system, required finite element model of the die bonder is generated, and structural analysis is performed. Vibration analysis of the pick-up head is also performed using developed finite element model at operation frequency range. As a result of the analysis, deformation, stress, and natural frequency of the die bonder are investigated.

• Journal of Korean Home Economics Education Association
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• v.24 no.4
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• pp.59-75
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• 2012

This study investigated the self-perception of body image and awareness of diet of high school students in Zibo city, China. The data were collected from 260 high school students through the self-administered questionnaires. Frequency analysis, t tests, one-way ANOVA, Duncan's multiple range tests, factor analysis and Cronbach's alpha test were conducted by SPSS Windows V.19.0. The results were as follows. In the self-perception of body image, two fifths of the respondents thought of themselves as standard body image. More female respondents thought of themselves as fat persons compared with male respondents. The level of concern about diet was generally low and the mean for pursuit of skinny figure was highest in the awareness of diet. The percentage of correct answers of knowledge about diet was not that high, and one fifths of respondents had experience of diet. The respondents practiced fasting therapy, exercise therapy, food therapy, sweat therapy, drug/appliance therapy, and therapy using professional organization in order for diet.

• Analytical Science and Technology
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• v.14 no.5
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• pp.422-431
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• 2001

One pulp manufacture facility was selected as surveying facility to examine the discharged amount and generation mechanism of dioxins excepts for bleaching stage wastewater. In recovery and finishing process, 2,3,7,8-TCDF, OCDD and OCDF were mainly detected, and the ratio of PCDDs and 1,2,3,4,7,8-HxCDD as the concentration of 2,3,7,8-substitute isomer were discharged which is known as the typical emission pattern of pulp and paper manufacture facility, and the 1,2,3,7,8-PeCDD and 1,2,3,4,7,8-HxCDD were discharged more than 90% in toxic equivalent concentration. Also, the OCDD and 2,3,7,8-TCDF for 2,3,7,8-isomer concentration, and 1,2,3,7,8-PeCDD and 2,3,7,8-TCDF as toxic equivalent concentration were discharged in effluent. The detected PCDDs/PCDFs concentration were surveyed 0.2266 ng-TEQ/L for influent and 0.0377 ng-TEQ/L for effluent.

• Journal of the Mineralogical Society of Korea
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• v.21 no.4
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• pp.435-442
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• 2008

Natural, synthetic, and treated diamonds were studied by NMR and EPR. It was demonstrated that natural and synthetic diamonds, treated and non-treated diamonds, high pressure high temperature (HPHT) treated and electron beam treated diamonds could be distinguished among each other based on the $^{13}C$ NMR spectra acquired for relatively short periods of 100 minutes. The $^{13}C$ NMR linewidths of gem quality synthetic diamonds were broader than 1.6 ppm due to the paramagentic effects of transition metals, generally used as catalysts, while the linewidths of gem quality natural diamonds were narrower than 0.5 ppm regardless of the methods of treatment. The linewidth (0.5 ppm) for a HPHT treated, gem quality natural diamond was as broad as more than twice of the linewidth (0.2 ppm) of an electron beam treated diamond. The $^{13}C$ NMR signal intensities of treated, gem quality natural diamonds were as strong as more than 10 times of the intensities of non-treated, gem quality natural diamonds. When correlated with the concentrations of the paramagnetic defects (electrons) obtained from the EPR spectra, the relative $^{13}C$ NMR signal intensities increased in proportion to the concentrations of the paramagnetic electrons contained in each sample but the electron beam treated diamond was an exception. This suggested that the lattice component, in addition to the paramagnetic defect component, should also be considered in determining the $^{13}C$ NMR signal intensity of the electron beam treated diamond.

• Proceedings of the KAIS Fall Conference
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• 2011.05b
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• pp.824-827
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• 2011

본 논문에서는 자동차 시트 리클라이너 기어의 파인 블랭킹 성형 실험을 통하여 V-링 설치 위치에 따른 기어의 다이 롤 높이 변화를 검토하였다. 3 종류의 다이 편과 가이드 플레이트 편을 설계하여 파인 블랭킹 금형을 제작하였으며 650 ton 파인블랭킹 프레스에서 성형 실험을 수행하였다. 실험으로부터 제품을 취출하여 다이 롤 높이를 측정하여 분석한 결과 기어 모듈과 관계없이 V-링 설치 위치가 가이드 플레이트에서 멀어짐에 따라 다이 롤 높이가 증가함을 파악할 수 있었다. 이와 같은 결과는 향후 파인 블랭킹 금형의 V-링을 설계할 때 다이 롤 높이를 최소화하기 위하여 유용하게 활용될 수 있을 것이다.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.112-114
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• 2008

AC 전동기용 다이나모 시스템은 동력흡수방식을 중심으로 제작되어 많이 사용되고 있으나, 속응성 및 내구성등이 열악하여 유지 보수등에 다소 어려움을 겪고 있어 소형 전동기를 중심으로 유도전동기를 이용한 다이나모 시스템에 관한 연구가 증가하고 있는 추세이다. 현재 소형 AC 전동기를 이용한 다이나모 시스템에 관한 연구가 진행되어 있으나 수십 kW급 전동기의 운전에만 제한되어 있다. 본 논문에서는 200kW급 AC 다이나모미터의 설계 및 제어에 대하여 서술한다. 기존 데이터 취득방식의 단점을 보완한 초고속 통신모듈을 내장한 데이터 송수신 시스템을 이용하여 AC 다이나모미터의 특성을 개선하였다. 실험을 통하여 본 논문에서 제안한 시스템의 설계 및 제어를 검증한다.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2002.04a
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• pp.119-120
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• 2002

소각로, 산업공정 등 다양한 배출원을 가지고 있는 다이옥신은 식품, 피부접촉, 대기 및 토양 통의 매체를 통하여 인간의 건강과 자연 생태계에 유해 영향을 미치고 있다. 환경 중 다이옥신의 배출량은 극미량이기는 하나 높은 지용성 물질로써 환경 매체간 이동 및 먹이사슬을 통해 생체농축현상을 일으키는 것이 밝혀지면서 그로 인한 유해성 야기되기 시작하였으며, 특히, 2001년 미국 환경보호청에서 다이옥신에 대한 재평가를 통해 2,3,7,8-TCDD는 인체 발암물질로, 다이옥신은 인체 발암 유발 가능 물질로 분류하고 있어, 선진국에서는 다이옥신에 대한 적극적인 연구가 진행되고 있다. (중략)

• Proceedings of the KWS Conference
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• 2007.11a
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• pp.251-253
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• 2007

현재 다이아몬드 공구에서 극세선에 브레이징 공정을 이용하여 다이아몬드를 접합하는 기술은 국내외 적으로 전무한 상태이다. 이 연구는 금속 와이어에 다이아몬드를 브레이징을 실시하여 최적의 와이어 브레이징 공정법을 개발 하는데 있다. 다이아몬드와 금속필러메탈 접합 계면에서의 금속성분과 탄화물의 거동을 분석하며, 브레이징에 따른 와이어의 물성 변화를 관찰하였다. 금속필러로는 Ag-Cu-5Ti(wt.%)을 사용하였으며, 와이어는 스테인리스를 이용하였다. 브레이징 공정은 진공 접합 장치를 이용하여 $800{\sim}1000^{\circ}C$에서 유지시간 $5{\sim}30$분로 실시하였다. 브레이징된 다이아몬드는 $900{\sim}950$도, 유지시간 10분 사이에서 각각 건전한 계면과 표면을 얻을 수 있었으며, 계면에서 Ti-rich상과 화합물이 확인되었다. 또한 열처리 따른 와이어의 최적의 건전한 상태를 고찰 하였다. 다이아몬드와 Ag계 브레이징 필러의 계면에서의 미세조직 및 화학반응의 메커니즘은 SEM, EPMA, XRD를 이용하여 분석하였다.