• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 C
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• pp.1543-1546
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• 1994

Ignitabilility of explosive gas mixture by spark of dry cell in case of short circuit by accident was studied for the purpose of evaluation of intrinsically safe characteristics of dry cell that manufactured in Korea. IEC type spark test apparatus, $21{\pm}2$ Vol% of hydrogen - air mixture, and dry cell that produced in Korea was used for the experiment. The result of this research could be used for design, manufacturing, and using the intrinsically safe electrical apparatus.

• 전기학회논문지
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• 제60권2호
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• pp.301-308
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• 2011

This paper deals with the coupled electromagnetic-mechanical field analysis for short-circuit electromagnetic force of the dry-type transformer. The short-circuit currents are calculated using external circuit in accordance with short-circuit test equipment. According to short-circuit current, the generated magnetic leakage flux density in dry-type transformer model is calculated by finite element method. The radially-directed electromagnetic forces in windings are calculated using electromagnetic field analysis and then axially-directed electromagnetic forces in windings are calculated using electromagnetic-mechanical field analysis. The calculated axially-directed electromagnetic forces in high voltage winding are compared to those of measured ones and showed good agreement with experimental results.

• 한국표면공학회지
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• 제50권5호
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• pp.373-379
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• 2017

Dry processes like evaporation and sputtering in vacuum chamber are difficult to make a uniform, large area and high quality film on thin PET substrate because of PET degradation and bad adhesion. On the other hand, wet processes like electro or electroless plating have complex processes and require high environmental cost. In this study, we successfully prepared $2{\mu}m$ Zn/Cu/Ni multilayers coated on $12{\mu}m$ polyethylene terephthalate (PET) substrate by using dry-wet mixing processes. Their surface electric resistances were evaluated around $0.2{\Omega}$ by using 4 probe measurements. Furthermore, their corrosion resistance also evaluated by natural potential test and compared with other wet, dry and mixing process samples.

• 대한한방내과학회지
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• 제28권1호
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• pp.97-105
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• 2007

Objectives : This study investigated the correlation between dry mouth and comprehensive diagnosis of Qi xu and Qi yu in patients with halitosis. Methods : We surveyed 124 halitosis patients by reviewing the questionnaires from the Halitosis Clinic in the Hospital of Oriental Medicine, Kyunghee University from January 2004 to March 2006. The halitosis questionnaires contained self-awareness of halitosis, self-assessed severity of halitosis, dry mouth and taste abnormality. Among comprehensive diagnosis of Qui Xue Shui, Qi xu and Qi yu parts were investigated by questionnaire and physical examination, and each Qi xu and Qi yu part scores were summed. Winkel tongue coating index was estimated by investigator, the level of volatile sulfur compounds were measured by halimeter, and salivary function was assessed by salivary scan test. All patients were divided into two groups based on salivary scan test (salivary function normal and decreased). Results : Qi xu score of halitosis patients with decreased salivary function was higher than normal halitosis patients. There was highly significant correlation between Qi yu score and dry mouth, and another significant correlation between self-assessed halitosis severity and dry mouth was noted. Conclusions : The results of this study suggest that Qi yu condition influences dry mouth in halitosis patients, and halitosis is affected by dry mouth. Therefore. we assume that treating Qi yu condition can be a potentially effective way of treating dry mouth and halitosis.

• Journal of Microbiology and Biotechnology
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• 제24권8호
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• pp.1034-1043
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• 2014

This study determined the effect of light intensity and photoperiod on the dry cell weight and total amount of carotenoids in four isolates of purple non-sulfur bacteria obtained from shaded and exposed microhabitats of a mangrove ecosystem in Kota Kinabalu, Sabah, Malaysia. The initial isolation of the bacteria was carried out using synthetic 112 medium under anaerobic conditions (2.5 klx) at $30{\pm}2^{\circ}C$. On the basis of colony appearance, cell morphology, gram staining, motility test, and 16S rRNA gene sequencing analyses, all four bacteria were identified as Afifella marina. One of the bacterial isolates, designated as Af. marina strain ME, which was extracted from an exposed mud habitat within the mangrove ecosystem, showed the highest yield in dry cell weight ($4.32{\pm}0.03g/l$) as well as total carotenoids ($0.783{\pm}0.002mg/g$ dry cell weight). These values were significantly higher than those for dry cell weight ($3.77{\pm}0.02g/l$) and total carotenoid content ($0.706{\pm}0.008mg/g$) produced by the isolates from shaded habitats. Further analysis of the effect of 10 levels of light intensity on the growth characteristics of Af. marina strain ME showed that the optimum production of dry cell weight and total carotenoids was achieved at different light intensities and incubation periods. The bacterium produced the highest dry cell weight of 4.98 g/l at 3 klx in 72 h incubation, but the carotenoid production of 0.783 mg/g was achieved at 2.5 klx in 48 h incubation. Subsequent analysis of the effect of photoperiod on the production of dry cell weight and total carotenoids at optimum light intensities (3 and 2.5 klx, respectively) revealed that 18 and 24 h were the optimum photoperiods for the production of dry cell weight and total carotenoids, respectively. The unique growth characteristics of the Af. marina strain ME can be exploited for biotechnology applications.

• 한국치위생학회지
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• 제15권4호
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• pp.671-677
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• 2015

Objectives: The purpose of the study was to examine the influencing factors of self-reported dry mouth in the employees in social welfare facilities. Methods: A self-reported questionnaire was completed by 260 employees in social welfare facilities from January 5 to 30, 2015 by convenience sampling method. Except 25 incomplete answers, 215 data were analyzed by t test, one way ANOVA, Pearson's correlation coefficient analysis, and multiple linear regression analysis using SPSS 180. program. The questionnaire consisted of general characteristics of the subjects, health-related characteristics, whole body dryness and self-reported dry mouth. The oral health-related quality of life was measured by five point Likert scale, and a higher score indicated a lower quality of life. Results: The self-reported dry mouth in the employees in the social welfare facilities varied by the general health status, stress, oral health status and oral malodor. The self-reported dry mouth was closely related to the quality of life and the four subfactors including dryness of skin, eye, lip and nasal mucosa. The quality of life had the influence on the self-reported dry mouth, nasal mucosa dryness, eye dryness, and oral malodor in order. Conclusions: The self-reported dry mouth was closely related to whole body dryness and the quality of life. It is necessary to develop the quality of life improvement programs that prevent and manage the dry mouth and whole body dryness in the employees in the social welfare facilities.

• 마이크로전자및패키징학회지
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• 제11권1호
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• pp.21-28
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• 2004

Polytetrafluoroethylene (PTFE/Teflon ) 인쇄회로기판용 미세 피치 솔더 범프 형성을 위해 dry film photoresist (DFR)를 photolithography 공정에 적용하였다. DFR lamination을 위한 test board는 폭 100$\mu\textrm{m}$와 두께 18$\mu\textrm{m}$의 copper line들이 100-200$\mu\textrm{m}$의 간격으로 배열된 형태로 디자인하였다. 15$\mu\textrm{m}$의 두께를 갖는 DFR을 hot roll laminator를 사용하여 lamination 온도와 속도를 변화시켜가면서 lamination 공정 실험을 수행하였다. 실험 결과, PTFE 인쇄회로기판에 DFR을 lamination하는 공정의 최적 조건은 lamination 온도 $150^{\circ}C$, 속도 약 0.63cm/s였다. UV exposure 및 development 공정을 거쳐 저융점 솔더 재료인 인듐을 증착하였다. DFR 박리 순서에 따른 두 가지 다른 reflow 공정을 통해 최소 지름 50$\mu\textrm{m}$, 최소 피치 100$\mu\textrm{m}$를 갖는 인듐 솔더 범프를 형성하였다.

• 한국건축시공학회지
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• 제13권2호
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• pp.131-138
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• 2013

본 연구는 최근 제주도 지역에서 현무암 가공과정에서 발생되는 폐기물인 석분슬러지를 재활용하기 위한 방안으로써 일반 시멘트몰탈에 사용되는 잔골재 대신에 현무암 석분슬러지의적용가능성에 대해 실험하였다. 드라이 몰탈의 재료로서의 기초적인 성능을 평가하기 위해 압축강도와 휨강도를 평가하고, SEM을 통해 미세구조를 관찰하였다. 현무암 슬러지 대체율 21%까지는 압축 및 휨강도는 증가하였으며, 보통 드라이몰탈보다 약 40% 강도 증진 효과가 있다. 현무암 슬러지의 대체율 약 20%이상에서는 상대적으로 수화생성물이 적게 생성되었다. 본 연구를 통해 현무암 슬러지 폐기물의 활용성을 확인할 수 있었으며, 콘크리트 2차 제품의 성형에도 가능할 것으로 판단된다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.449-449
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• 2011

We reported the direct effect of intrinsic surface energy of dry adhesive material to the Van der Waals and capillary forces contributions of the total adhesion force in an artificial gecko-inspired adhesion system. To mimic the gecko foot we fabricated tilted nanohairy structures using both lithography and ion beam treatment. The nanohairy structures were replicated from Si wafer mold using UV curable polymeric materials. The control of nanohairs slanting angles was based on the uniform linear argon ion irradiation to the nanohairy polymeric surface. The surface energy was studied utilizing subsequent conventional oxygen ion treatment on the nanohairy structures which resulted in gradient surface energy. Our shear adhesion test results were found in good agreement with the accepted Van der Waals and capillary forces theory in the gecko adhesion system. Surface energy would give a direct impact to the effective Hamaker constant in Van der Waals force and the filling angle (${\varphi}$) of water meniscus in capillary force contributions of gecko inspired adhesion system. With the increasing surface energy, the effective Hamaker constant also increased but the filling angle decreased, resulting in a competition between the two forces. Using a simple mathematical model, we compared our experimental results to show the quantitative contributions of Van der Waals and capillary forces in a single adhesion system on both hydrophobic and hydrophilic surfaces. We found that the Van der Waals force contributes about 82.75% and 89.97% to the total adhesion force on hydrophilic and hydrophobic test surfaces, respectively, while the remaining contribution was occupied by capillary force. We also showed that it is possible to design ultrahigh dry adhesive with adhesion strength of more than 10 times higher than apparent gecko adhesion force by controlling the surface energy and the slanting angle induced-contact line of dry adhesive the materials.

• 한국항만경제학회지
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• 제34권4호
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• pp.181-190
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• 2018

본 연구는 2012년 1월부터 2018년 5월까지의 주별 건화물선 운임과 원자재 가격 자료를 사용하여 두 변수간의 비대칭적인 관계를 다음의 두 가지를 중심으로 실증 분석한다. 첫째, 원자재가격의 거시경제지표에 대한 비대칭성을 2단계 경계(threshold) 공적분 검정모형으로 추정한다. 둘째, 기존의 원자재가격 변화의 무역수지에 대한 비대칭관계 검정을 보다 고빈도 건화물선 운임지수로 우회해서 검정한다. 추정결과 기존의 선형 분석과 대조적으로 하한과 상한에 대한 각각의 경계값이 상이한 비대칭성을 갖는 것으로 드러났다. 이는 불규칙적인 수익률 변동을 유발하는 급격한 잔차의 변동 구간이 원자재 가격과 건화물선 운임간의 선형의 장기균형관계가 성립하지 않도록 함을 의미한다. 따라서 이상의 추정결과는 급격한 가격 변화를 분석에 고려하기 위해서는 불규칙(irregular)적인 변동성을 제어하는 무반응(band of inaction)구간을 모형에 포함하는 것이 필요함을 의미하며 기존의 원자재가격의 무역수지에 대한 비대칭성과 일치하는 실증분석 결과다.