http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : 여운택 (검색결과 6 건)
- 무료
- 기관 내 무료
- 유료
-
-
-
-
呂運澤,車文豪 大韓小兒齒科學會 1986 大韓小兒齒科學會誌 Vol.13 No.1
The author has compared and analyzed the factors influencing the caries experience by means of oral inspection and questionnaire. The selected subjects for this study were 453 children (boys 240, girls 213) in 3rd grade of elementary school in Seoul. The obtained results were as follows: 1. The more mothers' daily tooth brushing frequencies were, the more children's daily tooth brushing frequencies were. 2. As children's frequencies of between-meal confection consumption increased, the number of decayed deciduous teeth increased significantly. 3. The children's dental knowledge was not significantly related to caries experience and daily tooth brushing frequency. 4. As children's daily tooth brushing frequencies increased, the number of decayed deciduous teeth decreased significantly. 5. As mother's education level and family income increased, children's the number of decayed deciduous teeth deceased significantly and the number of filled deciduous teeth increased significantly.
-
실 규모 태양열 집열판 제작을 위한 구리 및 알루미늄 기판에의 태양광 선택흡수박막 전착;Pulse Current Electrolysis 적용
이태규,김동형,김형택,여운택 한국에너지학회 1996 에너지공학 Vol.5 No.2
태양열 집열판의 효율을 증대시키기 위하여는 집열판에 조사되는 태양광의 흡수율을 높이고 복사에 의한 열손실을 감소시키는 선택적 박막을 집열판에 입히는 것이 중요한 인자이다. 본 실험에서는 이와같은 광학적 특성을 지니게 하고 동시에 전류효율이 우수한 pulsecurrent 전해법을 도입하여 실제 실용화 규모인 230 cm$\times$60 크기의 대형 기판에 선택흡수박막의 전착을 실시하였다. 도금액의 조성은 크롬산 280 g/$\ell$, propionic acid 15g/$\ell$, 그리고 제 2첨가제10g/$\ell$이었으며, 도금 대상기판으로는 구리와 알루미늄이 사용되었다. 구리 기판의 경우에는 선택흡수박막의 흡수율이 약 0.98이고 복사율은 약 0.17의 광학적 성질을 보였으며, 30$0^{\circ}C$공기 중에서 24시간동안 열처리 후에도 광학적 우수성을 지니고 있어 상품적 가치가 매우 우수하다고 판단되었다. 알루미늄 기판의 경우에는 흡수율이 약 0.97, 복사율이 0.15로서 광학적 성질은 구리 기판에 비해 다소 떨어지지만, 열전도도와 경제성을 고려하면 상품적 가치가 충분하다고 생각된다. 또한 이와 같은 대형기판을 적용하여 안정된 태양광 선택흡수박막의 성공적 제조로 공정의 단순화 및 대량생산 기술을 확보하였으며, 상용화에 돌입하게 되었다. It is one of the most important factors to enhance the efficiency of the solar collectors by in-creasing collecting efficiency and decreasing heat loss. The pulse electrodeposition method has been involved in this study to improve characteristics of the solar selective coating on 230cm${\times}$60cm substrates and electrical efficiency of the process. The composition of the electrolyte was 280 g/$\ell$ chromic acid, 15 g/$\ell$ propionic acid, and 10 g/$\ell$ appropriate additive. 230cm${\times}$60cm copper and aluminium sheets were utilized as the substrates. It has been observed that the black chrome coatings exhibited reasonable optical properties for commercialization when the plating parameters were properly controlled; the absorptance was 0.98 and 0.97 and omittance was 0.17 and 0.23 for copper and aluminium substrate, respectively. This study implies that the pulse current electrolysis method could be applied to the large scale substrates, and the various products can be avilable after the consideration of the thermal conductivity, heat transfer efficiency and cost problems of the substrates.
-
흑색 황산3가크롬을 이용한 태양열 흡열판 선택흡수막 도금기술
엄태인(Ohm Tae-In),여운택(Yeo Woon-Tack),김동찬(Kim Dong-Chan) 한국태양에너지학회 2013 한국태양에너지학회 논문집 Vol.33 No.3
One of the most important factors that have a large influence on performance of the solar water heater system is performance of the solar collector, more detailedly, coating technology on the surface of the solar collector, which can provide high solar absorptance and low emittance. The core of the coating technology is to coat solar selective surfaces. In this study, various performance experiments are carried out using Cr₂(SO₄)₃・15H₂O coating technology. Here, IGBT(Insulated Gate Bipolar Transistor) of 5000A-15V was used as the surface processing rectifier which can stably output power and also can control voltage and current. The plating solution mainly contains black chrome<SUP>+3</SUP> concentration, H-y Conductivity, N-u Complex, NF Additive and NC-2 Wetter. Before applying the black chrome coating on the copper plate, optimal conditions are provided by using various preprocessing methods such as removal of fat, activation, electrolytic polishing, nickel strike, copper sulfate plating and bright neckel plating, and then the automatic continuous coating experiment are performed according to plating time and cathode current density. In the experiment, after the removal of fat, chemical polishing, nickel strike and activation processes as the preprocessing methods, the black chrome coating was performed in a plate solution temperature of 28℃ and a cathode current density of 18A/㎠ for 90seconds. The thickness of chrome and nickel on the coated plate is 0.389㎛, 159㎛ respectively. As a result of the coating experiment, it showed the most excellent performance having a high solar absorptance of 98% and a low emittance of 5±1% when the black chrome surface had a thickness of 0.398㎛.
DBpia연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
