• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1993년도 춘계학술대회 논문집
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• pp.79-84
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• 1993

This paper describes the development of lithium rechargeable cell. $LiCoO_2$ is recently recognized as a suitable cathode active material of a high voltage, high energy lithium rechargeable batteries because $Li^+$ ion can be electrochemically deintercalated/intercalated from/to $Li_xCoO_2$. The transition metal oxide of $LiCoO_2$ was investigated for using as a cathode active material of 4V class Li rechargeable cell. $LiCoO_2$ cathode was prepared by using a active material of 85 wt%, graphite powder of 12 wt% as a conductor and poly-vinylidene fluoride of 3 wt% as a binder. The electrochemical and charge/discharge properties of $LiCoO_2$ were investigated by cyclic voltammetry and galvanostatic charge/discharge. The open circuit voltage of prepared $LiCoO_2$ electrode exhibited approximately. potential range between 3.32V and 3.42V. During the galvanostatic charge/discharge, $LiCoO_2/Li$ cell showed stable cycling behavior at scan rate of 1mV/sec and potential range between 3.6V and 4.2V. Also its coulombic efficiency as function of cycling was 81%~102%. In this study the $LiCoO_2/Li$ cell showed the available discharge capacity of 90.1 mAh/g at current density of $1mA/cm^2$ and cell discharge voltage range between 3.6V~4.2V.

• 한국치위생학회지
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• 제3권1호
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• pp.13-24
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• 2003

The researcher worked with a total of 158 high school girls visiting the scaling practice room at the department of dental hygiene in Jinju Health college from November 11, 2002 to December 4, 2002, having their teeth scaled, observing their teeth and interviewing them with the aid of questionnaires. The findings can be summarized as follows. 1. The survey on the understanding of dental health and the attitudes of the subjects shows the following results : "I have never learned how to brush teeth" (65.8%: 104 girls); "I brush my teeth twice a day" (57.0%: 90 girls) : "I brush my teeth for 2 minutes"(44.3%: 70 girls): "I brush my teeth vertically and horizontally" (53.2%: 84 girls): "( brush my teeth, gum and tongue" (462%: 73 girls): "I use one brush for two months" (40.5%: 64 girls); "I don't have any floss" (582%: 92 girls): "I have never had my teeth scaled" (84.2%: 133girls) : "Smoking is bad for the teeth" (77.8%: 123 girls): "Drinking is bad for the teeth" (48.7%: 77 girls): "I have ever visited dental clinics" (92.4%: 146 girls). 2. The study on part of the teeth most exposed to caries shows the following results : Mandibular right first molar(79.8%: 126 girls): Mandibular left first molar(77.5%: 124 girls), Mandibular left second molar(70.2%: 111 girls). Mandibular right second molar(65.7%: 104 girls). Maxillary left first molar(59.5%: 94 girls): Maxillary left second molar(59.5%: 94 girls): Maxillary right first molar(58.2%: 92 girls). Maxillary right second molar(50.7%: 80 girls) 3. The statistics on the subjects' caries show the following results: DMF rate: 943%: DMFT rate: 25.61%: DMFT index: 7.17 teeth : DT rate: 4651%: FT rate: 52.25%: MT rate: 124% 4. The survey on dental caries statistics, dental health, dental health behavior, and the subjects' attitudes shows the following results: The worse the subjects' dental health was(r=-327, p<.001), the more they visited dental clinics(r=.195, p<.05), the higher DMT rate, DMFT index were; The more the subjects visited dental clinics(r =.359, p<.001), the higher DT rate was; The worse the subjects teeth went(r=-.197, p<.05), the higher MT rate was. It is necessary that systematic and substantial dental health education for high school students should be carried out in regard to plaque control, fluoride application, diet control, pit & fissure sealant as a part of developing national health policies designed for the dental health of the teenagers.

• 한국산학기술학회논문지
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• 제10권9호
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• pp.2478-2484
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• 2009

본 연구는 서울시에 소재한 S남자고등학교 1학년 220명을 대상으로 구강검진결과 아래와 같다. 구강증상 경험 결과 치아 파절 경험이 없는 학생이 85.5%, 치아 지각과민 경험이 없는 학생이 76.8%로 조사되었다. 치아 통증 경험이 없는 학생이 90.9%의 결과를 나타내었다. 치주질환 경험이 없는 학생이 86.4%, 구강내 통증 경험이 없는 학생이 98.2%, 구취 자가 증상 경험이 없는 학생이 88.2%의 결과를 나타내었다. 구강보건행태결과 지난 1년간 치과병원을 방문한 경험이 없는 학생이 73.6%로 조사되었다. 하루 동안 아침식사 후에 이를 닦는 학생이 57.3%로 가장 많았으며, 과자 등 단음식이나 콜라 등 청량음료를 즐겨 먹지 않는 학생이 19.1%, 현재 불소가 들어있는 치약을 사용하고 있는 학생이 19.5%로 조사되었다. 구강검진결과 우식치아가 없는 학생이 55.9%, 우식치아가 있는 학생 44.1%로 조사되었다. 치주질환으로 치석형성을 앓고 있는 학생이 79.2%로 대부분을 차지였다.

• 대한환경공학회지
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• 제30권4호
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• pp.409-414
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• 2008

상전이 방법을 이용하여 전기흡착용 다공성 탄소전극을 제조하였다. 활성탄소분말(ACP)과 Polyvinylidene fluoride(PVdF) 용액을 혼합한 전극슬러리를 제조한 후 나이프 캐스팅 방법으로 전극슬러리를 흑연박막 위에 코팅하였다. 코팅된 전극을 비용매인 증류수에 침지시켜 다공성 탄소전극을 제조하였다. ACP의 함량비(50.0, 75.0, 83.3, 87.5, 90.0 wt%)를 변화시켜 전극을 제조하여 ACP 함량에 따른 탄소전극의 물리적, 전기화학적 특성을 분석하였다. SEM 사진을 통해 제조된 탄소전극의 표면을 관찰한 결과 상전이에 의해 미세한 기공들이 전극 표면에 균일하게 형성됨을 확인할 수 있었다. 또한 전극의 평균 기공 크기는 72.7$\sim$86.4 nm로 나타났으며 ACP의 함량이 증가할수록 기공의 크기는 감소하였다. 제조된 전극들에 대해 cyclic voltammetry(CV) 분석법으로 전기화학적 특성을 분석하였다. 모든 전극에서 전형적인 전기이중층에서의 흡착 및 탈착반응을 나타내었다. 전극의 축전용량은 ACP의 함량비가 증가할수록 크게 증가하였으며 ACP 함량이 50.0 wt%일 때 2.18 F/cm$^2$, 90.0 wt%일 때 4.77 F/cm$^2$의 축전용량을 나타내었다.

• 한국치위생학회지
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• 제7권1호
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• pp.91-103
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• 2007

The purpose of this study was to pave the way for the development of oral health promotion programs for children from the low-income class. The subjects in this study were 322 children from the city of Incheon. Some of them visited local childcare centers, and the others attended six different adjacent elementary schools. Their awareness of oral health, oral health behavior and preventive-treatment experience were investigated in May 2005, and whether there were any characteristics in their visit of dental institutions was checked. Besides, whether their parents advised them to brush their teeth before turning in was examined. The findings of the study were as follows: 1. 22.0 percent of the children investigated were visiting local childcare centers, and 78.0 percent weren't. The guardians of the former group largely received high-school(50.7%) and middle-school or lower education(22.5%), and those of the latter group mostly received high-school(41.0%) and college- or higher education(35.5%)(pE0.001). The common monthly mean house-hold income of the former was one million won or less(54.9%) or ranged from 1.01 to 2.00 million won(19.7%), and the most prevalent monthly mean household income of the latter was between 2.01 and 3.50 million won(28.7%). The second most dominant monthly mean household income of the latter ranged from 1.01 to 2.00 million won(28.3%), and the third most common one was 3.50 million won or more(12.0%)(pE0.001). 2. The most prevalent daily toothbrushing frequency among the local childcare center visitors was twice(39.4%), followed by three times(19.7%). The third largest group of the visitors brushed their teeth after each meal(19.7%). The most dominant daily toothbrushing frequency among the non-users of local child care centers was twice(54.2%), followed by three times(29.1%)(pE0.01). As to the way of toothbrushing, 58.2 percent of the visitors and 74.9 percent of the non-visitors brushed their teeth by turning their toothbrush or up and down(pF0.05). 62.0 percent of the former and 74.9 percent of the latter always brushed their teeth before turning in, and whether they visited local childcare centers made a significant difference to that(pE0.05). 3. 69.7 percent of the non-visitors were always advised by their parents to do toothbrushing before turning in, and the visitors who were given the same advice all the time numbered 29.6 percent(pE0.001). 4. 56.4 percent of the visitors and 72.1 percent of the non-visitors had ever visited dental institutions over the past year. Dental hospitals and clinics were identified as the dental institutions that they visited the most, and they mostly received dental-caries treatment or had a tooth out there. 49.3 percent of the visitors and 35.1 percent of the non-visitors had ever had a toothache. 5. Sealant was experienced by 42.3 percent of the visitors and 46.2 percent of the non-visitors to prevent dental caries(pF0.05). 33.8 percent of the visitors underwent fluoride application, and that rate was higher than that of the non-visitors with the same experience that stood at 22.7 percent(pE0.05). The visitors mainly acquired knowledge on oral health through other channels that weren't specified in the questionnaire(28.2%), and the non-visitors did it mostly at dental clinics(39.0%)(pE0.001).

• 치위생과학회지
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• 제10권5호
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• pp.379-385
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• 2010

본 연구는 유아교육기관 교사의 구강건강지식 및 구강건강실천정도를 파악하고자 유아교육기관에서 근무하고 있는 교사 169명을 대상으로 설문조사 하였으며, SPSSWIN 14.0을 이용하여 분석한 결과 다음과 같은 결론을 얻었다. 1. 구강건강지식정도에 있어서 치아우식증 관련지식 평균 7.97(9), 잇솔질 2.66(3), 치주조직병 2.86(5), 불소 2.42(5), 식이 1.04(2)로 나타났으며, 전체 24문항을 기준으로 평균 16.98로 100점으로 환산시 70점 정도의 구강건강지식 수준을 보였다. 2. 구강건강실천정도는 혀닦기를 하는 경우가 4.22로 가장 높은 반면, 정기구강검진에 있어서는 2.60으로 낮게 나타났다. 전체 구강건강실천정도는 3.11정도의 수준을 보였다. 3. 일반적 특성에 따른 구강건강지식과의 차이는 전체적인 지식에 있어 30대 연령 17.47, 5년 이상-10년 미만의 교육경력 17.50, 대졸이상 17.27, 원장인 경우가 18.26, 교육경험이 있는 경우가 17.01로 높게 나타났으나 통계적으로 유의한 차이는 없었다. 4. 일반적 특성에 따른 구강건강실천정도와의 차이는 연령에 있어서 당분섭취제한, 정기구강검진, 구강위생보조용품사용, 혀닦기, 전체적인 구강건강실천정도에 있어 나이가 많을수록 실천정도가 높은 것으로 나타났고, 통계적으로도 유의한 차이를 보였다. 5. 구강보건지식정도와 구강건강실천정도와의 관계는 전체적으로 통계적으로 유의한 차이는 없었지만 각 영역별로 구강보건지식이 높을수록 실천정도가 높음을 확인할 수 있었다. 이상의 결과로 교사들을 대상으로 한 다양한 구강보건교육 프로그램이 개발되어 지속적인 구강보건교육을 통한 지식의 향상은 물론 구강보건실천 향상도 매우 중요하다고 사료된다.