• Journal of Nutrition and Health
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• v.51 no.4
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• pp.295-306
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• 2018

Purpose: Koreans' internet and smartphone usage hours are steadily increasing and the dependence of young people on smartphones is causing social problems. Therefore, this study was conducted to examine health and dietary habits, as well as hair mineral contents according to the level of dependence of smartphone use among adolescents to clarify the interrelation of smartphone dependence, lifestyle, dietary behavior, and mineral nutrition status. Methods: A total of 80 smartphone-addicted adolescents participated in this study and were divided into three groups (general, potential and danger group) according to smartphone dependence. The subjects' lifestyles and dietary behaviors were then surveyed, and hair mineral contents were analyzed. Results: Higher smartphone dependence was associated with lower average weekly sleeping time and later first smoking age. In the danger group, the rate of eating fast and the rate of snacking twice a day was also relatively high. Parents (45.0%) and mobile (30.0%) were the factors having the greatest influence on an individual's dietary behavior. In the hair mineral analysis, all subjects had lower selenium concentrations and higher lead concentrations than normal. In addition, the levels of aluminum in the danger group were higher than in the normal range and the highest among the three groups. Conclusions: It is necessary to guide adolescents to use smartphones correctly and manage dietary habits. In addition, careful attention is needed the mineral nutritional status of smartphone-addicted adolescents.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.314-315
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• 2012

최근들어 반도체 및 디스플레이 소자의 구조가 복잡해짐에 따라 다층 박막 증착에 대한 중요성이 날로 증가하고 있다. 본 연구에서는 다층 박막을 효율적으로 증착하기 위해 회전이 가능한 육각건을 개발하였고, 이를 이용하여 에너지 절약형 단열 유리 증착 공정을 구현 하였다. 개발된 회전형 육각건은 기존 플래너형 스퍼터링 건의 확장형으로서 최대 6개의 물질을 하나의 챔버에서 증착이 가능하도록 구성되었다. 기존 공정의 경우 서로 다른 물질 증착을 위해서는 각각의 챔버가 필요한 반면, 회전형 육각건을 이용할 경우 하나의 챔버에서 공정을 진행할 수 있어 원가 절감이 가능하다. Fig. 1은 개발된 회전형 육각건의 모식도로서, 스퍼터링 타겟이 장착 가능한 건과, 회전부로 구성되어 있다. 이를 이용하여 투명전극-금속-투명전극-금속-절연체로 구성되어 있는 에너지 절약형 단열 유리용 다층 박막 증착 공정을 개발하였다. 이때 알루미늄이 도핑된 ZnO (AZO)는 RF 마그네트론 스퍼터로, 금속 박막은 DC 스퍼터, $SiO_2$ 및 SiN과 같은 절연 박막은 $O_2$와 $N_2$ 분위기에서 반응성 RF 스퍼터로 각각 증착하였다. Base pressure는 $10^{-7}$ torr였으며, 증착 시 공정 압력은 1~3 mTorr로 조정하였다. 증착 균일도 향상을 위해 20 rpm의 속도로 기판을 회전시켰다. Fig. 2(a)는 ZnO-Ag-ZnO 구조로 이루어진 다층 박막의 단면을 관찰한 투과전자 현미경 사진으로 각 층간의 계면이 뚜렷하게 나타남을 확인할 수 있으며, 각 층간의 intermixing 현상이 발생하지 않음을 확인 가능하다. 이를 보완하기 위해 Fig. 2(b)에서 보는 바와 같이 XPS를 이용하여 depth profile을 측정하였다. 각 층에서 서로 다른 물질이 발견되는 현상, 즉 교차 오염이 발생함에 따라 나타나는 intermixing 없이 거의 순수한 형태의 ZnO, Ag 박막 성분이 검출되었다. 이는 6개의 서로 다른 물질이 장착된 회전형 육각건을 이용하여 고 품질의 다층 박막 증착이 가능함을 제시하는 결과이다. 증착된 다층 박막의 균일도는 3.8%, 가시광선 영역에서 80% 이상의 투과도, 면저항 값은 3 ${\Omega}/{\Box}$ 이하를 보임으로서 에너지 절약형 단열 유리로서의 사양을 만족시키는 결과를 제시하였다.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.22 no.3
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• pp.127-134
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• 2016

In this study, Biodegradable masterbatch (M/B) was prepared by different kinds and content of biodegradable catalysts added to oxo biodegradable plastics. The bio film was prepared by adding biodegradable M/B to the polyethylene pellet, and the change of physical properties by UV and heat treatment and the stability as food packaging material were confirmed. As a result of the physical property change, Fe salt and Al salt bio film was superior to Ni salt bio film about a decrease in physical property. However, considering the raw material cost and industrial availability, M/B containing Fe salt was selected and additional experiments were conducted by concentration. The bio films prepared with Fe salt M/B 1.0, 1.5 and 2.0 wt% showed excellent physical properties.

• The Korean Journal of Financial Management
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• v.12 no.1
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• pp.33-56
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• 1995

본(本) 연구(硏究)는 자본구조이론과 전통적 연구에서 제시된 변수를 통합하고 횡단면(橫斷面) 요인(要因)과 시계열(時系列) 요인(要因)을 결합하여 우리나라의 자본구조결정 요인을 식별할 수 있는 이론적(理論的) 모형(模型)을 제시하여, 또한 제시된 모형을 한국증권시장(韓國證券市場)의 자료(資料)를 이용하여 실증적(實證的)으로 분석(分析)하였다. 그리고 실증적 분석에는 횡단면(橫斷面) 자료(資料)와 시계열(時系列) 자료(資料)를 결합하는 패널자료추정법(資料推定法)을 사용하였다. 본(本) 연구(硏究)에서 제시된 자본구조이론(資本構造理論)과 관련된 결정 요인으로는 기업(企業)의 성장기(成長機)을, 내부주주(內部株主)의 지분율(持分率) 그리고 내부주주수(內部株主數)의 비율 등을, 전통적 횡단면 요인으로는 경영위험(經營危險), 자산구성(資産構成), 수익성(收益性), 기업규모(企業規模) 등을, 그리고 전통적 시계열 요인으로는 법인세율(法人稅率)과 물가수준(物價水準) 등을 제시하였다. 본(本) 연구(硏究)에서 다루는 실증분석기간은 1981년 1월부터 1990년 12월까지의 10년간이었으며, 추출된 표본기업(標本企業)의 수(數)는 104개사이다. 실증적 분석결과, 본(本) 연구(硏究)에서 제시된 설명변수들이 자본구조(資本構造)의 변동(變動)을 49.91%정도 설명하고 있으며 설명변수 중 기업(企業)의 성장기회(成長機會), 내부주주(內部株主)의 지분을, 경영위험(經營危險), 수익성(收益性), 기업규모(企業規模), 물가수준(物價水準) 등은 자본구조의 결정 요인으로 통계적인 의미를 갖는 변수로 밝혀졌으며 회귀계수(回歸係數)의 부호도 기대하였던 바와 일치하고 있다. 질산으로 처리된 것이 컸고 0.75 M과 1.0 M의 질산을 사용했을 때는 작음이 확인되었다. 이상의 실험결과들로부터 친수성인 $NH_4Y$형 제올라이트를 소수성의 것으로 변환시키기 위한 수증기의 온도는 $500^{\circ}C$와 $600^{\circ}C$가, 그리고 질산의 농도는 0.5 M이 적합한 것으로 결론지을 수 있고, 이와 같은 결론은 BET비표면적과 TPV값과 같은 경향을 보인 벤젠과 톨루엔의 흡착용량측정결과로 입증되었다. 탈알루미늄된 제올라이트들의 수분에 대한 Si/Al비와 흡착용량은 각각 높은 농도의 질산으로 처리된 것일수록 증가하고 감소하여 소수성이 증가함을 나타내었다.(不適合性)이 나타났다. 본 연구는 기존의 기대수익률(期待收益率) 위주의 요일효과(曜日效果) 분석에서 주식수익률(株式收益率)의 분산(分散) 즉, 변동성(變動性)에 촛점을 두어 분석하였으며, 이는 투자자의 정확한 위험측정(危險測定)수단의 제공이라는 면에서 의의(意義)가 있을 것으로 생각된다.據金) 운용(運用)에 관한 정책수립시(政策樹立時) 금융선진국(金融先進國)의 증거금(證據金) 정책운용(政策運用)을 통한 시장관리(市場管理) 경험(經驗)을 어느 정도 참고할 수 있음을 시사한다고 할 것이다. 한다. 실증분석결과는 본문의 <표 1>에 제시되어 있으며 그 내용을 간략하게 요약하면 다음과 같다. (A) 실증분석모형 : 본 연구에서는 다기간 자산가격결정모형중에서 대표적인 Lucas (1978)모형을 직접 사용한다. $$1={\beta}\;E_t[\frac{U'(C_{t+1})\;P_t\;s_{t+1}}{U'(C_t)

• Journal of Mushroom
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• v.12 no.4
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• pp.287-292
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• 2014

This study investigated the packaging status and sensory quality of fresh-cut mushroom products from retail markets. Fifty one fresh-cut mushroom products were surveyed / purchased from discount stores in four cities in January (winter), March (spring), August (summer), and October (autumn) 2009. Collected fresh-cut mushrooms include single variety products like whole oyster mushroom and winter mushroom, diced or sliced oak mushroom, sliced king oyster mushroom, and ready-to-cook mixed mushroom products. Most fresh-cut mushrooms were packed in trays made of aluminum, polystyrene (PS), polyethylene terephthalate (PET), nylon materials covered with PVC (polyvinyl chloride) wrap or solid PP (polypropylene) and PS. Eighty nine percent of the covers were labeled with manufacture and expiration date. Collected samples showed severe browning (10%) and off-flavor (4%). The percentage of products with a rating of 'good' or better in overall quality was 90%. Moreover, Survey showed seasonal differences in sensory qualities. All of the collected fresh-cut mushrooms in autumn and winter had high marketability. However, Mushroom products collected in spring and summer had lower quality, hence requires treatment to prevent browning and off-flavor.

• Clinical and Experimental Pediatrics
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• v.49 no.1
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• pp.18-23
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• 2006

Purpose : The reliability of hair mineral analyses regarding nutritional status, environmental exposure or diseases is controversial. The aim of this study was to determine the normal reference range of hair mineral concentration of Korean children. Methods : We examined hair mineral concentrations of 223 children(3-12 yrs old, 110 boys, 113 girls, mean age $8.8{\pm}2.2$ yrs old) living in the northern area of Seoul. The trace elements including six toxic elements(Al, As, Cd, Ba, Hg, Pb) and 11 nutritional elements(Na, Mg, P, K, Ca, Cr, Mn, Fe, Cu, Zn, Se) were analyzed by inductive coupled plasma mass spectrometry(ICP-MS). Results : The mean concentrations of Ca and Mg were higher in girls than in boys. The mean concentrations of Cd, Pb and Cr were higher in boys than girls. The Zn, Ca, Mg, Cu and Hg levels in hair samples were positively correlated with increasing age. The Zn levels of the Korean children's hair samples appear to be lower than that of other countries' reference values. Conclusion : There are considerable differences in hair mineral concentrations by age, sex and race. Additional research is needed to establish Korean reference values, and to evaluate the usefulness of hair mineral analyses as a screening tool for nutrition- and environment-related childhood diseases.

• Resources Recycling
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• v.14 no.3
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• pp.16-36
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• 2005

The quantity of passenger cars in industrial countries has been significantly increased in recent years. According to prognoses, this tendency is likely to continue in the forthcoming future. As a direct consequence, an increase of End-of Life-Vehicles (ELV) will confront us with the problem of "ELV-Recycling". In order to cope with this situation, the European regulation for the treatment of End-of-Life-Vehicles (09/2000) has been transferred to national law in Germany (ELV-Regulation from 1 July 2002). The long term aim is to reduce residues from the ELV-treatment to less than 5 wt% from 30 wt% within the next 10 years (2015). For that reason, there is a need for innovative and more efficient recycling techniques tailored to future materials in automobiles. The design process at automotive industry is continuously changing due to the strong demand on optional equipment and new technical solutions for fuel saving. Light materials, such as aluminum and plastics, consequently become more important and cause a decrease of ferrous metals. Since plastic materials are often used as compounds, a separation into initial material types by means of mechanical recycling methods is not possible. For that reason, efficient recycling can only be realized by introducing recycling-friendly car designs. In the end an integrated approach of auto makers and recycling industry is of decisive significance for the fulfillment of future regulations.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.27 no.4
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• pp.212-219
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• 2017

To become a person that is suitable to the 'High-Touch' generation where emotion takes over, we can focus on 6 skill including design, story, harmony, empathy, play, and meaning. Among these skills, harmony with design was chosen as the most important skill. Design can be seen as the basic element of all business, but it will be difficult to match the flow of the future Sensibility and intuitive generation with just the modern design that has been made based on reasonable and objective information and knowledge. This study suggests system and standardization of Sensibility surface processing design that satisfies great quality, attractive quality and Sensibility quality by applying surface processing design of product and Sensibility cognitive factors felt by the consumer by setting differentiated strategy and CMF (Color, Material, Finishing) understanding along with the importance of design materials in primary aspect. By considering the efficacy/characteristic of new surface processing characteristic/differentiation/possibility of implementation according to setting direction of differentiated CMF strategy per type of parts applied to the product, visual surface processing sample was implemented. Through this, it is expected that practical communication connected tool and Sensibility surface processing design's strategic access framework can be applied by understanding and sharing comprehensive elements such as target product, part type, applied material, applied surface processing, surface color, surface texture, and implementing feeling to environments such as designers, CMF designers, surface processing experts, and engineers in IT, electronics, and other areas. when developing a product.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.5
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• pp.628-636
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• 2018

Because large buoys are mainly made of steel, they are heavy and vulnerable to corrosion by sea water. This makes buoy installation and maintenance difficult. Moreover, vessel collision accidents with buoys and damage to vessels due to the material of buoys (e.g., steel) are reported every year. Recently, light buoys adopting eco-friendly and lightweight materials have come into the spotlight in order to solve the previously-mentioned problems. In Korea, a new lightweight buoy with a 7-Nautical Mile lantern adopting expanded polypropylene (EPP) and aluminum to create a buoyant body and tower structure, respectively, was developed in 2017. When these light buoys are operated in the ocean, the visibility and angle of light from the lantern installed on the light buoys changes, which may cause them to function improperly. Therefore, research on the performance of light buoys is needed since the weight distribution and motion characteristics of these new buoys differ from conventional models. In this study, stability estimation and motion analyses for newly-developed buoys under various environmental conditions considering a mooring line were carried out using ANSYS AQWA. Numerical simulations for the estimation of wind and current loads were performed using commercial CFD software, Siemens STAR-CCM+, to increase the accuracy of motion analysis. By comparing the estimated maximum significant motions of the light buoys, it was found that waves and currents were more influential in the motion of the buoys. And, the estimated motions of the buoys became larger as the sea state became worser, which might be the reason that the peak frequencies of the wave spectra got closer to those of the buoys.

• Journal of Food Hygiene and Safety
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• v.27 no.1
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• pp.42-49
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• 2012

This study was carried out to investigate the toxicity of food Red No.2 in the Sprague-Dawley (SD) female rat for 4 weeks. SD rats were orally administered for 28 days, with dosage of 500, 1,000, 2,000 mg/kg/day. Animals treated with food Red No.2 did not cause any death and show any clinical signs. They did not show any significant changes of body weight, feed uptake and water consumption. There were not significantly different from the control group in urinalysis, hematological, serum biochemical value and histopathological examination. In conclusion, 4 weeks of the repetitive oral medication of food Red No.2 has resulted no alteration of toxicity according to the test materials in the group of female rats with injection of 2,000 mg/kg. Therefore, food Red No.2 was not indicated to have any toxic effect in the SD rats, when it was orally administered below the dosage 2,000 mg/kg/day for 4 weeks.