• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2002년도 추계학술대회 논문집
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• pp.109-112
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• 2002

The supersonic jet discharging from a petal nozzle is known to enhance mixing effect with the surrounding gas because it produces strong longitudinal vortices due to the velocity difference from both the major and minor axes of petal nozzle. In the present study, the supersonic free jet discharging from the petal nozzle is investigated experimentally. The nozzles used are 4, 6, and 8 lobed petal nozzles with a design Mach number of 1.7, and the flow fields are compared with a circular nozzle with the same design Mach number. The pitot impact pressures are measured using a fine pilot probe. The flow fields are visualized using a Schlieren optical method. The results show that the petal nozzle has more increased supersonic length compared with the circular jet.

• 한국식품영양학회지
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• 제12권4호
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• pp.415-420
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• 1999

Petal of Azalea(Rhododendron mucronulatum Turcz) was incubated with Gokja at 3$0^{\circ}C$ for seven days and the essential oil components of petal of Azalea before and after incubated were analyzed using a GC/MSD. Ten or more essential oil components including n-heneicosane n-tricosane n-tetreacosane n-pentacosane n-heptacosane n-nonacosane and n-hentriacontane were identified from the petal of Azal-ea before incubated while oxygen-containng compounds including (E)-heptenal 2-ethoxy-1 -hexanol n-hexadecanoic acid methyl ester 9, 12-octadecadienoic acid methyl ester 9,12,15-octadecatrienoic acid methyl ester, n-octadecanoic acid methyl ester n-eicosanoic acid methyl ester and 9-docosaenoic acid methyl ester as well as n-alkanes such as n-tricosane that n-pentacosane were identified from the petal of Azalea after incubated. These results suggest that n-alkanes in petal of Azalea might be degraded and some oxygen-containing compounds such as aldehyde, esters and /or acids might be produced when pet-al of Azalea is incubated with Gokja.

• 한국자원식물학회지
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• 제29권4호
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• pp.376-384
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• 2016

쉬땅나무족 15분류군의 화판의 미세형태학적 형질을 주사 전자현미경으로 관찰하여 화판 향축면, 배축면의 세포 외형, 배열, 수층벽, 큐티클의 미세형태를 자세히 기재하였으며, 분류학적, 계통학적 유용성을 검토하였다. 쉬땅나무족의 화판은 유두상 또는 원추형 유두상(PCS), 직사각형의 주름판상(TRS)로 확인되었으며, 향축면, 배축면의 화판 구조에 따라 크게 세 유형으로 구분하였다. Type I. PCS-TRS, Type II. PCS-PCS, Type III. TRS-TRS (향축면-배축면). 구분된 이들 유형과 수층벽, 큐티클 표면의 형태는 족 내 속간/종간 진단 형질로 유용하였을 뿐 아니라, 계통학적으로도 그 유용성이 확인되었다. 또한, 화판 표면의 세포의 미세형태와 수분매개자(곤충을 통한 충매)와의 연관성을 나타내는 추가적인 사례로 제시하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.2133-2138
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• 2003

In general, flow entrainment of surrounding gas into a supersonic jet is caused by the pressure drop inside the jet and the shear actions between the jet and the surrounding gas. In the recent industrial applications, like supersonic ejector system or scramjet engine, the rapid mixing of two different gases is important in that it determines the whole performance of the flow system. However, the mixing performance of the conventional circular jet is very low because the shear actions are not enough. The supersonic jet discharging from a petal nozzle is known to enhance mixing effects with the surrounding gas because it produces strong longitudinal vortices due to the velocity differences from both the major and minor axes of petal nozzle. This study aims to enhance the mixing performance of the jet with surrounding gas by using the lobed petal nozzle. The jet flows from the petal nozzle are compared with those from the conventional circular nozzle. The petal nozzles employed are 4, 6, and 8 lobed shapes with a design Mach number of 1.7 each, and the circular nozzle has the same design Mach number. The pitot impact pressures are measured in detail to specify the jet flows. For flow visualization, the schlieren optical method is used. The experimental results reveal that the petal nozzle reduces the supersonic length of the supersonic jet, and leads to the improved mixing performance compared with the conventional circular jet.

• 대한수학회보
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• 제59권4호
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• pp.993-1010
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• 2022

In this paper, we establish some radius results and inclusion relations for starlike functions associated with a petal-shaped domain.

• 한국식품조리과학회지
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• 제27권5호
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• pp.523-530
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• 2011

This study was conducted to investigate antimicrobial, antioxidant and anticancer activities of Opuntia humifusa (OH) petal extracts. The methanol and hexane extracts of OH petals showed their highest antimicrobial activity against Clostridium perfringens. The OH petal butanol fraction had the best antioxidative peroxynitrite scavenging activity among OH petal extracts. The DPPH scavenging activity of OH petals was lower than the peroxynitrite scavenging effect. The hexane and methanol fractions at a concentration of 200 ${\mu}g$/mL inhibited proliferation >80% in four kinds of human cervical cancer cells(B16F10, HepG2, HT-29 and MCF-7). In particular, the anticancer effect against B16F10 human skin cancer cells at the same concentration was higher than that in the other cancer cells.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2004년도 제28회 KOSCO SYMPOSIUM 논문집
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• pp.49-56
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• 2004

A two-dimensional twin-jet counterflow system has been designed, in which two streams from two double-slit nozzles form a counterflow. This flow system enables one to systematically investigate various effects on non-premixed flames, including the non-premixed flame interaction, the edge flame behavior and the effect of curvature. Non-premixed flame interaction in the twin-jet counterflow system has been investigated numerically for methane fuel diluted with nitrogen. Three types of non-premixed flame(conventional counterflow flame, crossed twin-jet flame and petal shaped flame) were simulated depending on the combination of fuel/oxidizer supply to each nozzle. The extinction characteristics of non premixed methane flame in the twin-jet counterflow have been investigated numerically. The boundary of the existence of petal-shaped flames was identified for the twin-jet counterflow flames. Due to the existence of the unique petal-shaped flames, the extinction boundary for the twin-jet counterflow can be extended significantly compared to that for the conventional counterflow non-premixed flames, through the interaction of two flames. Through the comparison of the crossed twin-jet flame and the conventional counterflow flame, structure of the crossed twin-jet counterflow flame is analysed. Through the comparison of the petal shaped flame and the conventional counterflow flame, the extension of the extinction boundary for the twin-jet counterflow is investigated.

• Food Science and Biotechnology
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• 제15권2호
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• pp.260-263
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• 2006

In this study, we investigated the antimicrobial effect of 14 different herbal petal extracts on various foodborne and food spoilage bacteria. Herbal petal extracts were prepared with 70% ethanol followed by sequential hexane, chloroform, ethyl acetate, n-butanol, and water fractionation. Antimicrobial activity was highest in the ethanol fraction from roselle (Hibiscus sabdariffa L.) petals as determined by the paper disc method. The roselle ethanol extract retarded the growth of food spoilage bacteria in kimbap (rice rolled in dried laver). Foodborne microorganisms (e.g. Bacillus cereus and Clostridium perfringens), on the other hand, were most efficiently inhibited by the ethyl acetate fraction of the roselle petal extract as determined by growth inhibition curves. Our study shows that roselle petals harbor antimicrobial activity against foodborne and food spoilage microorganisms. The critical ingredient is highly enriched in the ethyl acetate fraction of the extract.

• 식물분류학회지
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• 제34권4호
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• pp.273-285
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• 2004

Lycopus속 15종의 화판(petal)과 악편(sepal)의 미세형태를 주사전자현미경과 실체현미경으로 관찰하여 그 분류학적 유용성을 검토하였다. Lycopus속 분류군들의 화관과 악에 분포하는 모용과 선모는 단세포 원주모(unicellular cylindrical trichome), 표면에 돌기가 있는 단세포 모용(unicellular trichome with papillae), 다세포 모용(simple multicellular trichome), 두상선모(capitate glandular trichome) 및 방패형 선모(peltate glandular trichome) 등 5 종류로 나타났으며, 모용의 종류, 분포, 밀도가 분류군마다 다르게 나타났다. 화관 안쪽면에 단세포 원주모(unicellular cylindrical trichome)의 분포 정도가 각 분류군마다 다르게 나타나, 그 분포 부위에 따라 4가지 유형으로 나눌 수 있었다. 악(calyx)은 악편이 갈라지는 정도와 악편 정단(apex)의 모양으로 4가지 형태로 구분할 수 있었다. 화판과 악편의 안쪽 빛 바깥면을 구성하는 세포의 형태는 그 위치와 분류군에 따라 다양하게 나타났다. 끝으로 관찰된 Lycopus속의 화판 및 악편 미세형태를 검토한 결과 종간 식별에 유용하였다.

• Journal of Plant Biotechnology
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• 제42권4호
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• pp.370-375
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• 2015

스프레이국화 '퍼플엔디'의 꽃잎을 이용하여 부정아유기에 효율적인 부정아 유기조건을 찾기 위하여 실시하였다. 배양재료로 사용한 꽃잎은 꽃봉오리의 개화진전단계(S1; 10% 개화, S2; 30% 개화, S3; 50% 개화, S4; 70% 개화)를 4단계로 하고 꽃잎부위는 꽃잎의 기부와 끝부분(TBOP; the basal of petal, TEOP; the end of petal)으로 나누어 MS무기염에 IAA와 BAP를 첨가한 배지에 배양하였다. 배양재료는 30% 정도 개화가 진전(S2)되었을 때 꽃잎을 채취하여 꽃잎을 하나씩 분리한 후 꽃잎 중간 길이에서 가로로 잘라서 꽃잎 끝부분(TEOP)을 사용하고 $1.0mg{\cdot}L^{-1}$ IAA와 $2.0mg{\cdot}L^{-1}$ BAP의 농도로 첨가한 MS배지에 치상하였을 때 79.2%의 부정아 형성과 33.4개의 유묘를 획득할 수 있었다. 재분화된 식물체의 배수성 분석결과 모본과 동일하였으며 온실에서 순화 후 정상적인 생육과 개화를 확인할 수 있었다.