• 한국추진공학회지
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• 제12권6호
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• pp.21-29
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• 2008

본 연구에서는 부분분사에서 작동하는 소형 축류형 터빈에서, 중요한 설계변수인 노즐에서의 출구유동각과 동익에서의 현절비를 변경하였을 때 발생되는 성능변화에 대하여 실험적인 연구를 수행하였다. 성능시험에 사용된 터빈은 단단으로 구성되며 로터의 평균반경은 35mm였다. 실험에서 최적의 설계변수를 찾기 위하여 세 가지의 현절비와 네 가지의 노즐에서의 출구유동각을 적용하였다. 터빈에서의 전체적인 성능평가를 위하여 총비출력으로 비교하였으며, 부분분사율이 3.4%인 경우에 동익에서의 현절비가 2.18일 때 최고의 성능이 얻어졌다. 이 값은 전분사 시에 적용되는 최적의 현절비에 비하여 74%나 증가한 결과이다.

• 패션비즈니스
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• 제12권2호
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• pp.42-58
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• 2008

The purpose of this study is to examine actual design cases of decorative detail in the Art Nouveau style from the end of 19th century to the beginning of 20th century, and create designs and fashion works to meet our contemporary fashion trends by means of over-decorative style, a characteristic of decorative detail. The characteristics of decorative detail in the Art Nouveau style can be outlined as follows: First, pleats appear with two major feels of solidity, undulated and curvilinear solidity based on gather(ruffle, frill/ flare and flounce) and regular and linear solidity based on linear pleats or tucks. Second, embroidery appears in various patterns developed with stitch of solid feel as well as a variety of coloration effects. Third, attachments are expressed by means of independent motif(applique, gloss effects(beads, sequins), affluent texture and mobility(fur, feather). Moreover, according to technical characteristics and expressive aspects of pleats, embroidery and attachments, it is found that decoration detail in the era of Art Nouveau is over-decoration style. Indeed, it appears in major expressive aspects such as rhythmical solid type, detailed prominence type, superficial touch type and profound volume type.

• 정보보호학회논문지
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• 제29권1호
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• pp.67-75
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• 2019

Solidity에서 다른 계약의 함수를 호출할 때 특정 문제로 인해 호출할 수 없으면 fallback 함수가 실행된다. 이 fallback 함수는 임의로 작성될 수 있는 함수로 어떤 동작을 하는지 정해지지 않았기 때문에 함수의 동작을 알 수 없어 공격에 이용되기 쉽다. 본 논문에서는 이러한 위험성을 개발자의 부담 없이 줄이기 위해 전처리기를 이용한 해결방법을 제안한다. 개발자는 새롭게 정의된 키워드를 이용해서 의사표시를 하고, 전처리기는 해당 키워드에 따라 상태변수와 조건문을 이용해서 전처리 과정을 진행하여 위험성을 줄인다.

• 한국유체기계학회 논문집
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• 제3권4호
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• pp.44-51
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• 2000

The present study has been conducted to design the high efficiency centrifugal compressor for a R134a turbo-chiller. The centrifugal compressor consists of an impeller with splitters, two vaneless diffusers, a low-solidity vaned diffuser and a volute. A cycle analysis program for a turbo-chiller was developed to obtain compressor design parameters and requirements. We have designed the high efficiency centrifugal compressor by applying the repeated design procedure including a meanline design, a 3D geometry generation and fluid dynamic loading calculations.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2000년도 유체기계 연구개발 발표회 논문집
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• pp.137-142
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• 2000

The turbulent broadband sound power from a forward curved bladed fan can be modeled by the trailing edge noise. The trailing edge noise is usually influenced by inflow turbulence, separation, and boundary layer on the blade. This paper reports the effects of the solidity (C/s) and the stagger angles upon the trailing edge noise with respect to the trailing edge shapes of circular-arc cambered blade of multi-bladed fan, and discusses the major physical mechanism of reduced noise lot the circular trailing-edged case.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.396-401
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• 2000

It is addressed that the turbulent broadband sound power from a sirocco fan can be modeled by the trailing edge noise. The trailing edge noise is usually influenced by inflow turbulence, separation, and boundary layer on the blade. The design parameters such as solidity(c/s) and stagger angle are specified to predict performance and noise level because the separation and slip velocity are strongly affected by them along with the flow coefficient. This paper reports the effects of the solidity and the stagger angle upon the trailing edge noise from the circular arc-shaped blade of sirocco fan.

• 한국의류학회지
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• 제18권2호
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• pp.244-251
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• 1994

The purpose of this study was to analyze conductive convective and radiative heat transfer characteristic of the nonwovens were studied by measuring thermal conductance at atmospheric and low air pressure. The results obtained were as follows . 1) As thickness of air layer Increased, overall heat transfer was decreased by reducing conductive and radiative heat trasfer. 2) The conductive and convective heat trasfer by air were in the range of 79~8971 of overall heat transfer. 3) As thickness of nonwoven increased for a given solidity, overall heat trasfer was decresed by increasing total thickness of air layer and by reducing conductive and radiative heat transfer. 4) For a given weight, increasing thickness is more effective than increasing solidity.

• 태양에너지
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• 제7권2호
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• pp.74-85
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• 1987

Performances of 3 different aerodynamic analytical models, single multiple and double multiple stream tube, for vertical axis Darrieus turbine were analyzed comparatively. From the study it has been found that the models derived from stream tube assumptions can be useful for simple prediction of basic design characteristics of Darrieus turbine. But, for a large tip speed and solidity ratios, the models has shown a certain limit in its applicability according to the formulation scheme applied. The results have shown that for the case having large tip speed and solidity ratios the consideration due to stream conditions, such as trailing vortices or wakes, should be included for accurate prediction of the aerodynamic performances of Darrieus turbine.

• 한국토양동물학회지
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• 제2권2호
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• pp.98-103
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• 1997

This study was investigated, from October to November, 1995, how environmental factors affected both the diversity and the ecology of soil microarthropods according to the sampling sites at althletic training park located in Chonju, Chonbuk. The results obtained are as follow: At the sampling areas, the soil microarthropods were identified into 6 classes, 15 orders, 17,145 individuals. Arachnida showed the highest individual rate (74.10%) in soil mictoarthropods and Acari occupied the great majority (97.98%) in Archinida. Collembola showed the highest individual rate (82.01%) in Insecta. Species planted at althletic training park were 10 famillies 12 genera 20 species 2 varietas 1 forma. In environmental factors which have an effect on the distribution of the soil microarthropods, acarina showed positive correlation for rate of carbon/nitrogen, soil moisture, soil acidity, and lead(Pb) and also negative correlation for solidity and intensity of lightness. Collembola and other animals showed negative correlation for solidity.

• 대한기계학회논문집B
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• 제39권8호
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• pp.693-702
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• 2015

본 논문은 NACA 익형의 블레이드를 가지는 다리우스 수직축 풍력발전기(VAWT)의 성능특성에 대한 연구이다. 다양한 설계변수를 이용한 다리우스 VAWT 의 최적 형상을 예측하기 위해서 블레이드 근처에서 나타나는 공력특성 및 박리유동, 유동과 블레이드 간의 상호작용, 이로 인해 유도되는 토크 및 출력특성 등을 분석하였다. 블레이드의 최적 형상 설계 및 주변 유동과의 상호작용 특성을 보기 위하여 다양한 인자들 (즉, 코드길이, 로터직경, 피치각, 블레이드의 두께비 및 비틀림각 등)을 고려하였다. 본 연구에서 연구결과로는 TSR 가 낮은 영역에서는 솔리디티가 큰 로터가 높은 출력계수를 가지는 반면, TSR 이 높은 영역에서는 솔리디티가 작은 로터가 높은 출력계수를 가진다. 블레이드의 익형이 안쪽으로 향하는 피치각은 $-2^{\circ}$와 비틀림각이 $0^{\circ}$ 일 때, 다리우스형 VAWT 가 최대 출력을 발생하였다.