• Journal of Advanced Marine Engineering and Technology
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• 제23권5호
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• pp.711-718
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• 1999

Current turbulence models including modified $K-{\varepsilon}-{\tau}$ turbulence model do not predict compression effect on turbulence accurately in an internal combustion engine. The $K-{\varepsilon}-{\tau}$ turbulence model was suggested to improve the predictability of compression effect by We et al. In this paper a numeri-cal study was performed to clarify the applicability of the $K-{\varepsilon}-{\tau}$ turbulenc model to the calculation of the in-cylinder flow of an axisymmetric engine. THe results using $K-{\varepsilon}-{\tau}$ turbulence model are compared to those from the modified $K-{\varepsilon}-{\tau}$ turbulence model and experimental data. The mean veloc-ity and rms velocity profiles using $K-{\varepsilon}-{\tau}$ turbulence model showed a better agreement with an experimental data than those of modifid $K-{\varepsilon}-e$ turbulence model.

• Journal of Ginseng Research
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• 제24권2호
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• pp.94-98
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• 2000

Tetracycline hydrochloride (TC) caused 100%, 50% and 20% mortality rates among rats injected with 40 mg, 30 mg and 20 mg/100g. b.w. respectively; while the morta]ity rates were decreased to 50%, 20% and 10% when Panax ginseng (2 mg/100g. b.w.) injected with TC during 72 hrs. post-injection. Subacute-toxicity study demonstrated that TC caused severe hepato-nephrotoxicity (demonstrated by biochemical analysis of serum including: transferases , alkaline phosphatase, total protein, glucose, cholesterol urea and creatinine) in rats injected i.p. with 10 mg and 5 mg/100g. b.w. for 7 days of daily injection . These signes of toxicity were greatly diminished by P. ginseng addition to TC doses.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2001년도 춘계학술대회 논문집
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• pp.241-248
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• 2001

The ductility of circular hollow reinforced concrete columns with one layer of longitudinal and spiral reinforcement placed near the outside face of the section and the steel tube placed on the inside face of the section is investigated. Such hollow sections are confined through the wall thickness since the steel tube is placed. The results of analytical moment-curvature analyses for such hollow sections are compared with those for the circular section with the sane diameter. In this study, moment-curvature analyses are conducted with Mandel's confined concrete stress-strain relationship in which the effect of confinement is to increase the compression strength and ultimate strain of concrete. The moment-curvature analyses confirmed that the ductility is primarily influenced on the ultimate strain. The variables influenced on the ultimate strain is the ratio and yield strength of confining reinforcement and the compression strength for confined concrete. From this ultimate strain - the transverse reinforcement ratio relationship, the transverse reinforcement ratio for circular hollow reinforced columns with confinement is proposed. The proposed transverse reinforcement ratio is confirmed by experimental results.

• The Korean Journal of Ecology
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• 제26권2호
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• pp.53-58
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• 2003

Ever-growing recreation, tourism and ecotourism worldwide have become a significant factor of resource degradation in many protected areas. Managers of these areas are increasingly challenged to implement policies, strategies and actions that would protect the resource base while providing quality visitor experience. One major issue in managing protected area visitations is that of carrying capacity, or the question of "how much use is too much\ulcorner". Scientific studies of visitor impacts, often known as recreation ecology, has generated a knowledge base that provides valuable input to the visitor carrying capacity management process adopted by the U.S. National Park Service. This paper aims at (a) providing an overview of recreation ecology research and its application in managing visitor carrying capacity, and (b) examining the relevance of recreation ecology to East Asian protected areas with special reference to the visitor capacity issue.ity issue.

• 한국세라믹학회지
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• 제36권4호
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• pp.444-450
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• 1999

Hydroxyapatite(HA) was spray-coated to alloy substrate(Ti-6Al-4V) using plasma-spray process for bioceramic application The coating morphology composition and crystallinity were influenced by following process parameters ; stand-off distance spray power level and auxiliary gas pressure. These parameters have been systematically varied in the present study to evaluate their relative influence on the coating qual-ity and to seek an optimum spraying condition. Amorphicity and decomposition of HA increased with stand-off distance and the imperfect coating layer was obtained at the short stant-off distance (55mm). The cry-stallinity of HA coating decreased with spray power level and auxiliary gas pressure but the bond strength between the HA coated layer and Ti alloy substrate increased with the spray power level.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2002년도 추계학술발표논문집 (중)
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• pp.1071-1074
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• 2002

최근 차세대 인터넷 환경의 표준 데이터 포맷으로 각광받고 있는 XML(eXtensible Markup Language)을 사용한 전자상거래 규격에 대한 국 내외적 표준화 작업이 가속화 되고있으며, 아울러 기업간 전자문서 교환시의 인증 및 보안문제 또한 필수적인 사항이 되어가고 있다. 본 논문에서는 XML표준화 기구에서 정의한 명세서 기반의 XSS(XML Secu.ity Suite) 라이브러리를 이용하여 기업간 전자문서 교환시 발생하는 보안문제를 해결하기 위한 전자서명 관리 시스템을 연구하였다.

• 조명전기설비학회논문지
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• 제15권1호
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• pp.1-6
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• 2001

조명업체에서 적분구를 이용한 광원의 전광선속을 측정하는데 기준광원으로 활용하기 위하여 신뢰성 높은 전광선속 표준전구를 개발하였다. 전광선속 표준전구는 공간세기분포가 균일하도록 되어 있으며, 사용시간 100[h]동안에 전광선속 변화율이 0.5% 이내로 양호한 안정도를 갖는다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.488-491
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• 2000

Bi-2223/Ag superconducting wires have been mainly prepared by a powder-in-tube method. The drawing and the rolling are main processes to increase the core density and wire length. In the fabrication of long wire, especially, the drawing should be precisely controlled to assure the filament homogeneity. In this paper, the influences of drawing die angle, bearing length and reduction ratio on the sausaging and the critical current density of the wire are investigated. Single cored and multi-filamentary wires are fabricated by PIT method with different conditions. The core densities and sausaging in the wires are investigated and are discussed regarding their relationship to the I$_{c}$. It was made clear that the geometry of drawing die is sensitively dependent on the sausaging. The improvement of I$_{c}$ was achieved by reducing the die angle and high core density.ity.

• 한국광학회지
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• 제11권2호
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• pp.85-90
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• 2000

CRT디스플레이의 화질 평가에는 위도, 콘트라스트, addressability, 시청거리 등의 다양한 물리적 특성치가 사용된다. 그러나, 최종적인 CRT디스플레이 화질의 비교·평가는 물리적 특성치가 아닌 실제 사용자가 느끼는 화질 즉, 주관적 인지 화질에 의해 이루어진다. 본 논문에서는 4종류 CRT모니터의 SQRI(SQuare Root Integral) 값과 다수의 피험자에 의한 주관적 화질 평가 점수와의 상관성이 비교되었다. 그리고, 이러한 SQRI법의 주관적 화질 평가 척도로서의 타당성을 바탕으로 모니터의 다양한 물리적 특성치가 주관적 화질에 미치는 영향이 검토되었다.

• 동아시아식생활학회지
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• 제11권6호
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• pp.498-505
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• 2001

흑미를 첨가한 반죽과 식빵의 품질을 조사하였다. 반죽에 흑미를 첨가함으로서 pH는 낮아졌으며 발효는 촉진되었다. 굽기 손실률은 흑미의 첨가량이 높을수록 낮았다. 흑미 첨가빵은 점착성과 탄력성은 낮았으나 부드러운 조직감이 있었으며, 관능검사 결과 흑미 5% 첨가빵은 와인빛깔로 색상에 대한 기호도가 높게 평가되었으며 대조구보다 촉촉한 느낌을 주었다. 흑미 첨가빵의 조직은 무첨가에 비하여 작은 전분입자의 수가 많으며 더욱 조밀하게 분포하였다. 이러한 경향은 흑미 첨가 비율이 높을수록 뚜렷하였다. 흑미 10% 첨가반죽에서는 렌즈형의 큰 전분입자가 변형된 형태로 관찰되었으며, 식감은 무첨가보다 쫄깃하나 다소 무거운 느낌을 주었다.