• 제목/요약/키워드: Waterdrop

검색결과 18건 처리시간 0.023초

충격파에 의한 물방울의 변형에 관한 경험적 해석 연구 (Empirical Analysis Research on Waterdrop's Deformation by Shock Wave)

  • 홍윤기;염금수;문관호
    • 한국군사과학기술학회지
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    • 제19권5호
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    • pp.638-644
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    • 2016
  • In this research, theoretical study on empirical analysis method to estimate waterdrop's deformation by shock wave is presented. Flow field is calculated using theoretical and empirical relations. Waterdrop's deformation including movement, size, mass, and orientation is modeled using empirical relations derived from existing experimental data. Developed method is applied to specific flight examples with arbitrary flight speed and vehicle's configuration. The flight speed is assumed to Mach number of 2 and 4. The diameter of waterdrop is varied from 1 to 5 mm. Waterdrops along the stagnation line in front of hemispherical nose with the radius of 50 mm and around a cone-shaped side wall with the half angle of 20 degree are considered. It is found that the maximum diameter of the waterdrop is increased up to 2.77 times the initial diameter. The mass is conserved more than 66.7 %. In the case of a cone-shaped side wall, waterdrop's orientation angles defined from the flight direction when the Mach number is 2 and 4 are calculated as 33.0 and 25.6 degree, respectively.

계면활성제 처리 농도가 무가온 플라스틱온실의 방적성, 환경 및 상추 생육에 미치는 영향 (Effect of Surfactant Concentrations on Anti-waterdrop, Environment and Lettuce(Lactuca sativa L.) Growth in Polyethylene Film Greenhouse)

  • 전희;이혜은;염성현;김학주;이시영;남윤일;김경제
    • 생물환경조절학회지
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    • 제12권4호
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    • pp.195-199
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    • 2003
  • 계면활성제(SF316+FB0800)가 처리된 폴리에틸렌 필름 시설에서 직경 9cm 원안의 필름 표면에 부착된 수적량은 무처리구에서 1.21 mL, 1% 처리구에서 0.15mL, 2% 처리구에서 0.07 mL가 측정되었다. 그러나 육안으로는 1%와 2% 처리구 사이에 차이를 관찰하기가 어려웠다. 수적량은 하루 중 오전 10시에 가장 많았고, 기온의 상승된 오후 2시에 적었다. 무처리구에 비하여 계면활성제 1%와 2% 처리구 사이에 차이를 관찰하기가 어려웠다. 수적량은 하루 중 오전 10시에 가장 많았고, 기온이 상승된 오후 2시에 적었다. 무처리구에 비하여 계면활성제 1%와 2% 처리구에서 투광율은 각각 9.3%, 12.9% 높았다. 기온과 습도는 계면활성제가 처리된 비닐하우스와 머처리 비닐하우스 사이에 뚜렸한 차이를 나타내지 않았다. 오전의 기온은 계면활성제 처리 비닐하우스에서 1~2$^{\circ}C$ 정도 높았으며, 지온의 경우는 계면활성제 처리시설에서 3~4$^{\circ}C$ 정도 높은 경향을 나타냈다. 겨울철 상추의 생육은 계면활성제가 처리된 필름으로 피복된 비닐하우스에서 빨랐다. 그러나 계면활성제농도 1%와 2% 처리구 사이에는 뚜렸한 차이를 보이지 않았다.

물방울무늬의 크기가 의복이미지에 미치는 영향 -원피스드레스를 중심으로- (Influence of the Size of Polka Dots on the Image of Clothes -Focused on One-piece Dress-)

  • 최혜원;류숙희
    • 한국의류학회지
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    • 제31권5호
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    • pp.742-752
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    • 2007
  • The purpose of this study is the image of clothing according to the change of the dots' size was analyzed and its influence on the formation of the image of polka dots clothing was investigated. White waterdrop patterns were designed on the 12 kinds of black texture using Photoshop and CAD program in regular arrangement of diamond figure, composed of white waterdrop(0.5cm, 1.0cm, 1.5cm and 2cm in diameter) and interval(diameter : interval-1 : 1, 1 : 2, 1 : 4). Applying above specification, the photograph stimulus of 12 kinds of X-line one-piece dress with wide square neckline and without sleeve or detailed ornament was presented on a screen in the same size as when putting it on. The image of polka dots clothes was investigated by questionnaire survey. The object of the study was 320 females aged between 16 and 29. Factor analysis, one-way ANOVA, $Scheff\acute{e}$ verification and two-way ANOVA using SPSS 10.0 were carried out for data analysis. Followings are the results: 1) The image of polka dots clothing consists of 4 factors as aesthetics, brevity, dynamism and lightweight. 2) The size of the dot has a great influence on the formation of the image of polka dots clothing. 3) The evaluations of the image of polka dots clothing were different depending on the age and physical image, the personal characteristics of the object of investigation.

물방울무늬의 간격이 의복이미지에 미치는 영향 - 원피스드레스를 중심으로 - (The Influence of the Interval of Polka Dots on the Image of Clothes - Focused on One-Piece Dress -)

  • 최혜원;류숙희
    • 한국의류산업학회지
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    • 제9권3호
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    • pp.278-285
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    • 2007
  • The purpose of this study is the image of clothing according to the change of the dots' interval was analyzed and its influence on the formation of the image of polka dots clothing was investigated. White waterdrop patterns were designed on the 12 kinds of black texture using Photoshop and CAD program in regular arrangement of diamond figure, composed of white waterdrop(0.5 cm, 1.0 cm, 1.5 cm and 2 cm in diameter) and interval(diameter : interval - 1 : 1, 1 : 2, 1 : 4). Applying above specification, the photograph stimulus of 12 kinds of X-line one-piece dress with wide square neckline and without sleeve or detailed ornament was presented on a screen in the same size as when putting it on. The image of polka dots clothes was investigated by questionnaire survey. The object of the study was 320 females aged between 16 and 29. Factor analysis, one-way ANOVA, Scheff$\acute{e}$ verication and two-way ANOVA using SPSS 10.0 were carried out for data analysis. The research finding are as follows. First, the image of polka dots clothing consists of 4 factors as aesthetics, brevity, dynamism and lightweight. Secondly, the interval of the dot has a great influence on the formation of the image of polka dots clothing. Lastly, the evaluations of the image of polka dots clothing were different depending on the age and physical image, the personal characteristics of the object of investigation.

도금 전처리공정에서 맞춤형 알칼리계 탈지제 개발 (Development of Alkaline Degreasing Agent for Electroplating Pretreatment Process)

  • 이승범;정구형;이재동
    • 공업화학
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    • 제21권3호
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    • pp.301-305
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    • 2010
  • 본 연구에서는 도금전처리 공정에서 사용되는 다양한 조성의 맞춤형 알칼리계 탈지제를 개발하고, 탈지제의 수명을 예측함으로 효율을 높임과 동시에 공정품의 불량을 줄이고자 하였다. 알칼리계 탈지제는 침지형 탈지제로 NaOH, $Na_2CO_3$, $Na_2SiO_3$, SLS 등을 일정비율로 첨가하여 제조하였으며, 제조된 탈지제의 성능평가를 위해 알칼리계 탈지액의 온도를 $40{\sim}50^{\circ}C$로 설정하여 30~40 min 동안 오염된 철 시편을 넣은 후 오염물을 제거하였다. 오염물이 제거된 시편은 물방울 맺힘실험과 Hull-cell 도금분석을 통해 탈지제의 성능 및 수명을 확인하였다. 최적 탈지제의 조성은 NaOH (30 g/L) + SLS (6.0 g/L) + $Na_2SiO_3$ (2.0 g/L) + $Na_2CO_3$ (40 g/L)을 추천할 수 있으며, 물방울맺힘 실험과 Hull-cell 도금 분석 결과 최적 탈지조건은 $50^{\circ}C$, 35 min인 것으로 나타났다.

적응성 방향 미분의 에지 검출에 의한 효율적인 접촉각 연산 (An Efficient Contact Angle Computation using MADD Edge Detection)

  • 양명섭;이종구;김은미;박철수
    • 융합보안논문지
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    • 제8권4호
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    • pp.127-134
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    • 2008
  • 본 연구는 투명 성질을 가진 물방울의 윤곽선에 대한 효율적인 검출을 통해 분석 장비의 자동 측정에 대한 정확성을 향상시키는 것을 목적으로 한다. 투명성질을 가지는 원의 윤곽선 검출을 위해 밝기 분포에 대한 국소적 미분 대신에 적응성 방향 미분(Adaptive Directional Derivative;ADD)이라는 비국소적 연산자를 도입함으로써 에지의 램프 폭의 변화에 무관하게 에지 검출에 적용할 수 있는 MADD(Modified Adaptive Directional Derivative) 알고리즘을 사용한다. 이 방법은 램프 구간 내에서 방향 미분 값을 가중치로 사용하여 픽셀들의 위치를 평균한 방향 미분의 국소 중심(Local Center of Directional Derivative;LCDD)등의 위치를 찾는 추가적인 과정없이, 정확한 에지 픽셀의 위치가 완전 선명화 사상에 의한 단순 계단 함수의 위치로 자연스럽게 결정될 수 있다. 제시된 에지 검출 방법을 표면분석 기술인 접촉각 연산에 적용하여 실험 및 결과 분석을 통해 제안 기법의 타당성 및 효율성을 검증한다.

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계면활성제 농도가 폴리에틸렌필름온실의 수적성에 미치는 영향 (Effect of Surfactants Concentration on Waterdrop in Polyethylene Film Greenhouse)

  • 전희;이혜은;김학주;이시영;남윤일;박태욱;도현성
    • 한국생물환경조절학회:학술대회논문집
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    • 한국생물환경조절학회 2003년도 춘계 학술대회 논문집
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    • pp.92-97
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    • 2003
  • 비닐하우스에서 피복자재로 폴리에틸렌(polyethylene), 초산비닐(ethylene vinyl-acetate) 및 염화비닐(polyvinylchloride)와 같은 연질필름을 90% 이상 사용하고 있으나 필름 표면에 물방울이 맺히는 것을 방지하는 무적성과 각종 먼지 등이 부착하는 것을 억제하는 방진성의 저하로 시설내 투광률이 5-l5% 떨어지고 다습하여 딸기와 같은 작물에 해로운 잿빛곰팡이병 발생이 심하여 생산성이 크게 떨어지고 있다('92, '97 원예연구소, '91 Jaffrin). (중략)

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남성복에 나타난 문양의 감성이미지와 선호도 (The Sensibility Image and Preference Degree of Pattern which Appeared on Men′s Clothing)

  • 박영희
    • 복식
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    • 제54권4호
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    • pp.113-127
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    • 2004
  • This study examined the trend of pattern which appeared throughout men's clothing fashion magazine from 1999 to 2002 and the influence which the demographic characteristic have on the sensibility dimension of pattern and the preference degree of kinds of pattern. The results of study were as follows. 1) The pattern which was used most frequently on recent men's clothing was a length stripe, and the representation technique which was used most frequently on recent men's clothing was the technique of a geometric expression. 2) The pattern which men and women preferred most out of ten kinds of patterns-length stripe, width stripe, oblique stripe, check, square, waterdrop, paisley, flower of style shape, flower of realistic shape, flower of shape-was a length stripe. 3) The sensibility dimension of pattern image was composed of fascination, dignity, daring, gentleness, and reality. 4) Because sensitivity dimension and kinds of pattern were significant according to the distinction of sex, vocation, academic career, income, this study can conclude the demographic characteristic have an influence on sensitivity dimension and kinds of pattern.

수성(水性)펜침(針) 대(對) 절연지부착평판간(絶緣紙附着平板間)의 방전특성(放電特性) (Discharge Characteristics from a Water-Penpoint-to - Insulator-Paper-Covered-Plate Airgap)

  • 문재덕;이대희
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1994년도 하계학술대회 논문집 C
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    • pp.1586-1588
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    • 1994
  • Some interesting corona characteristics of a airgap of penpoint-to-plate with a tracing insulator paper has been investigated in a temperature and humidity controlled metal chamber. It is found that the positive and the negative carriers in the plasma region could be understood from the waterdrop traces on the paper, which indicate the bombardment by the one of electron or positive gas particle from the plasma region of near the point. It is also found that a corona discharge could be used as a means of a humidifying, since the discharge makes dispersion of watersprays from the penpoint. And the negative corona was more effective for waterspray dispersion than the positive ones.

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