• 한국가시화정보학회:학술대회논문집
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• 2002.11a
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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.

• The Korean Journal of Food And Nutrition
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• v.12 no.4
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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.

• Korean Journal of Plant Resources
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• v.29 no.4
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• pp.376-384
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• 2016

A comparative petal micromorphology of 15 taxa of tribe Sorbarieae was carried out using scanning electron microscopy (SEM) in order to evaluate their taxonomic and systematic implication. The characteristics of both adaxial and abaxial side of petal epidermal cells such as shape, arrangement, anticlinal wall and cuticular sculpture were described in detail. The Sorbarieae petal epidermal cells were identified as papillate or conical papillate (PCS) and rectangular-rugose tabular (TRS). Three types of petal micromorphology were found within the tribe based on the cell patterns of adaxial and abaxial side. Type I. PCS-TRS, Type II. PCS-PCS, Type III. TRS-TRS (adaxial-abaxial side). The petal epidermal cell types, anticlinal cell wall, and cuticular sculpture represent not only taxonomical importance for identification between or within the genera but also systematic implication. Moreover, this study provides a relation between petal epidermal cell pattern and insect pollinator (entomophily; melittophily) as an additional case.

• Proceedings of the KSME Conference
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• 2003.04a
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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.

• Bulletin of the Korean Mathematical Society
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• v.59 no.4
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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.

• Korean journal of food and cookery science
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• v.27 no.5
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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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• 2004.06a
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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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• v.15 no.2
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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.

• Korean Journal of Plant Taxonomy
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• v.34 no.4
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• pp.273-285
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• 2004

A comparative micromorphology of petal and sepal of 15 species of Lycopus was undertaken to assess their usefulness in species identification and to evaluate their significance in the taxonomy using scanning electron microscope and stereo microscope. Five types of trichome are found within the genus: unicellular cylindrical trichome, unicellular trichome with papillae, simple multicellular trichome, capitate glandular trichome, and peltate glandular trichome. The types, distribution, and density of the trichomes show considerable variation among the taxa. The distributional pattern of the unicellular cylindrical trichomes on inner side of corolla is differed among the investigated taxa, and can be classified into four patterns. The apex shape of sepal and the incised position of calyx are also various and be recognizedas four patterns. The shape of cell composing in both outer and inner sides of petal and sepal are shown variously. Finally, the taxonomic significance of micromorphology of the petal and sepal in identification and elucidation of the genus Lycopus, especially among the species is also briefly discussed.

• Journal of Plant Biotechnology
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• v.42 no.4
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• pp.370-375
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• 2015

This experiment compared the regeneration conditions of the radiation mutant spray chrysanthemum 'purple ND'. The four different flower blooming stages (S1: 10% opened flower, S2: 30% opened flower, S3: 50% opened flower, and S4: 70% opened flower) and different petal parts (TBOP: the basal of petal and TEOP: the end of petal) were used to compare regeneration conditions between plants grown in MS medium supplemented with IAA and BAP. The highest adventitious shooting rate was identified in plants grown on the IAA $1.0mg{\cdot}L^{-1}$ and BAP $2.0mg{\cdot}L^{-1}$ when using the end of petal at the S2 stage. It displayed 79.2% regeneration and produced 33.4 shoots. Rooted plantlets were successfully established in the greenhouse, showing the same morphological characteristics of vegetative and reproductive organs with those of the mother plant. Flow cytometry analysis revealed no ploidy variation between the regenerated plants and the mother plant grown under greenhouse conditions.