• 천문학논총
• /
• 제30권2호
• /
• pp.637-639
• /
• 2015

The Korean very-long-baseline interferometry (VLBI) network (KVN) and VLBI Exploration of Radio Astrometry (VERA) Array (KaVA) is the first international VLBI array dedicated to high-frequency (23 GHz (K-band) and 43 GHz (Q-band)) observations in East Asia. To evaluate the imagine capability of KaVA, we performed imaging observations of three bright active galactic nuclei (AGNs) known for their complex morphologies: 4C 39.25, 3C 273, and M87 by KaVA at K-/Q-band. Our KaVA images reveal extended outflows with complex substructure such as knots and limb brightening, in agreement with previous observations by other VLBI facilities. Angular resolutions are better than 1.4 and 0.8 milliarcsecond (max) at K-/Q-band, respectively. KaVA achieves a high dynamic range of ~1000, more than three times the value achieved by VERA. We conclude that KaVA is a powerful array with a great potential for the study of AGN outflows, at least comparable to the best existing radio interferometric arrays.

• 천문학회보
• /
• 제45권1호
• /
• pp.42.3-42.3
• /
• 2020

We investigate the observational properties of Wolf-Rayet stars, suggest the constraint of their mass-loss rate and apply our results to the observed progenitor candidates of Type Ib/Ic supernovae (iPTF13bvn and SN 2017ein). For this purpose, we adopt the WR star models with various mass-loss rates and wind terminal velocities. We obtain the high resolution spectra of those models at the pre-supernova phase using the radiative transfer code CMFGEN. We verify the optically faint property of SN Ic progenitors and show that the optical faintness is mainly originated by the high effective temperature at the photosphere. We also show that a simple analytic model for WR winds using a constant opacity can roughly predict the photospheric parameters. We show that the change of the mass-loss rate and the terminal wind velocity critically affects the optical luminosity. We find the optical luminosities of SN Ic progenitor models with our fiducial mass-loss rate prescription are fainter than the detection limits. We also suggest the mass-loss rate of WR stars may not exceed 2 times of our fiducial value by comparing our predictions with the detection limit of SN Ib/Ic progenitors. The directly observed progenitor candidate of iPTF13bvn can be explained by our SN Ib progenitor models. We find that the SN 2017ein progenitor candidate is too bright and too blue to be a SN Ic progenitor.

• ALGAE
• /
• 제38권4호
• /
• pp.217-240
• /
• 2023

Sulfated polysaccharides (SPs) isolated from seaweed have emerged as remarkable bioactive compounds with a wide spectrum of biological activities and have substantial value in the scientific and industrial domains. The current study explores the diverse biological activities of SPs and their relationship with their structures. This aids in an in-depth examination of the multifaceted biological activities of SPs, including anticoagulant, anti-inflammatory, antiviral, antioxidant, and immunomodulatory properties, which underpin their potential health benefits. Furthermore, the current study explores the complicated properties of SPs, with their extraction methodologies and techniques for precise characterization. Elucidation of the commercial significance of SPs derived from brown, red, and green seaweed by highlighting their potential applications has emphasized their importance in human well-being. Further, this review emphasizes the challenges needed to overcome research and industrial innovations for SPs. Collaboration among researchers, industry stakeholders, and regulatory authorities can overcome these challenges and elevate the potential of SPs to revolutionize industries such as pharmaceuticals, cosmeceuticals, food, and biotechnology.

• 천문학회보
• /
• 제38권2호
• /
• pp.45.1-45.1
• /
• 2013

Type Ia supernovae (SNe Ia) are a powerful tool to investigate the expansion history of the universe, because their peak luminosity is as bright as a galaxy and is known as an excellent standard candle. Since the discovery of the acceleration of the universe based on the observations of SNe Ia, higher than ever accuracy of their peak luminosity is needed to investigate various problems in cosmology. We started a project to improve the accuracy of the calibration of the peak luminosity of SNe Ia by measuring accurate distances to nearby resolved galaxies that host SNe Ia. We derive accurate distances to the SN Ia host galaxies using the method to measure the luminosity of the tip of the red giant branch (TRGB). In this study we present the results for M66 and M96 in the Leo I Group which are nearby spiral galaxies hosting SN 1989B and SN 1998bu, respectively. We obtain VI photometry of resolved stars in these galaxies from F555W and F814W images in the Hubble Space Telescope archive. We derive the distances to these galaxies from the luminosity of the TRGB. With these results we derive absolute maximum magnitudes of two SNe (SN 1989B in M66 and SN 1998bu in M96). We derive a value of the Hubble constant from the optical magnitudes of these SNe Ia and SN 2011fe in M101 based on our TRGB analysis. This value is similar to the values derived from recent estimates from WMAP9 and Planck results, but smaller than other recent determinations based on Cepheid calibration for SNe Ia luminosity.

• 한국연초학회지
• /
• 제21권1호
• /
• pp.82-88
• /
• 1999

The present study was conducted to compare the relative efficiency of two different haploid breeding methods in tobacco varietal development. A single FI hybrid plant from cross of two flue-cured cultivars of Nicotiana tabacum L., Bright Yellow4(BY4) and NC95, was used to develop the 30 anther derived dihaploid (ADH) lines and maternally-derived dihaploid (MDH) lines utilizing Nicotiana africana, respectively. As compared with mid-parent, mean of ADH lines showed increase in number of leaves, delay in days to flower and narrow in width of leaf. However, no significant differences in the other investigated characters were recognized. MDH lines also showed narrow width of leaf, while no significant differences in the other characters were observed. The variations of the investigated characters were generally greater in ADH than MDH lines. MDH lines had higher height of plant and shorter days to flower than ADH lines, while the other characters did not show remarkable differences. The degree of heritability for each of the characters observed between ADH and MDH was almost the same. The characters showing high heritability value were height of plant, number of leaves, days to flower, and yield, while those showing relatively low value were length of leaf, width of leaf, and total alkaloid content. Predicted gains from selection for increased yield were calculated for both populations(ADH, MDH) and correlated responses associated with selection for yield were estimated. Height of plant, width of leaf, days to flower, and concentration of reduceing sugar would be expected to improve with selection for yield much faster in the MDH population than in the ADH.

• 한국식품저장유통학회지
• /
• 제3권2호
• /
• pp.137-143
• /
• 1996

In order to produce the high-quality of dried red pepper with respect to a color and a taste we developed a automatic drier equipped with combined several heat energies(ADCHE). and compared the quality of ADCHE-treated red pepper with that of the pepper treated with conventional dryings such as natural, hot-air, and far-infrared ray dryings. The results obtained were as follows : (1) The contents of capsanthin varied significantly with drying methods within the range of 1.7 to 6. 4mg/g dry weight. The capsanthin level of red pepper treated with far-infrared ray drying was higher than that of the pepper treated with ADCHE showed the highest at 51.46mg/g dry weight of three drying methods. (2) As a result of determination of color intensity of-red-pepper using-a colorimeter, the red color intensity of the peppers was affected by drying methods irrespective of drying temperature, and especially a value of red pepper treated with ADCHE was appeared to be 19. 1, indicated that this pepper have the most bright color intensity. (3) The contents of soluble browing subatances increased with a increase in drying temperature, but L* value of red pepper treated with ADCHE was appeared to be 0.187, indicated that this red pepper have the most clear red color (4) The changes of capsanthin level of red pepper according to drying methodes did not show significantly, but generally a decreasing rate of capsanthin levels were lower in that order ADCHE

• 한국연초학회지
• /
• 제14권1호
• /
• pp.24-32
• /
• 1992

The present study was conducted to compare the relative efficiency of two different haploid breeding methods in tobacco varietal development. A single F t hybrid plant from cross of two flue-cured cultivars of Nicotiana tabacum L., Bright Yellow4(BY4) and NC 95, was used to develop the 30 dihaploid lines by anther culture(F1-ADH) and maternally-derived doubled haploid utilizing Nicotiana africana(F1-MDH), respectively. As compared with mid-parent, ADH lines showed increasing in number of leaves, delaying in days to flower and narrowing in leaf width. However, no significant differences in the other characters investigated were recognized. MDH lines also showed narrow leaf width, while no significant differences in the other characters were observed. The variations of the characters investigated were generally greater in ADH than MDH lines. MDH lines had higher plant height and shorter days to flower than ADH lines, while other characters did not show remarkable differences. The degree of heritability for each of the characters observed between ADH and MDH was almost the same. The characters showing high heritability value were plant height, leaf number, days to flower, and yield, while those showing relatively low value were leaf length, leaf width, and total alkaloid content. Predicted gains from selection for increased yield were calculated for both populations(F1-ADH, F1-MDH) and correlated responses associated with selection for yield were estimated. Plant height, leaf width, days to flower, percent reducing sugar and disease resistance would be expected to improve with selection for yield much faster in the MDH population than in the ADH.

• 복식
• /
• 제33권
• /
• pp.189-199
• /
• 1997

The following contents are the results from the examination of unisex fetishism minimal and active which are Mods look. Unisex-becasue of the changing in musician and the role of sex Mods girl adopted much from men's clothing. The unisex mods look expressed in the 1990s is not the expression confronting the estab-lished value and the confusion of sex as it did in the '60s but possibly the appearance of a fashion trend. Fetishism-in the '60s the Mods look changed mens clothing into more wonman-like clothing which expressed their internal and external values of thinking. this fetishism phenomenon is also strongly expressed among the in the 1990s. This gives a future-orientid feeling by expressing with a modern sense the 60's fetish dress which used woman-like silhouettes bright and stretch fabric colorful and vivid tone. Minimal-The 60's Mods put on mini skirts called the revolution of length as a mode of re-sistance and mininmal dress as a way of ex-pressing the liberation of body and the con-sciousness of beauty. Minimal is reflected well on slim and fit jackets and pants and short and fit pants etc. mods look in the '90s also consists of the general trend of slim and fit silhouette. Active-Mods that reject the value of estab-lished generation in the 60s showed a sporty and casual trend on fashion. Mods works around clubs wore polo shirts and cadigan and Mods enjoys scooter often wore anorak parkas This active style of Mods approched to the young' casual with freshness expressing newly in the '90s polo shirts took a seat as an item of street fashion especially in the beginning of 1996. Mods in the 1960s shows well a fashion flow of the age as a street fashion which expresses the mental world reflected in politics econo-mics society and culture within the people of the age. These Mods looks revived in the early 1990's awaken an importance of the culture of the young as the cultural qualities included in Mods of the past life and this fashion trend expected to take a part as a symbol of fashion culture.

• 복식
• /
• 제57권4호
• /
• pp.45-60
• /
• 2007

Characteristics of Hanbok's traditional coloration have been carried on, based on social/cultural background of the past. Today, Hanbok is classified as traditional Hanbok, improved Hanbok, living Hanbok. Their designs, materials and colorations show significant differences. In this study, first, we have categorized and arranged the coloration trend of the women's Hanbok according to the types of coloration since 2000s. Secondly, Hanbok is classified as traditional Hanbok, improved Hanbok, and living Hanbok. And then examining their coloration trend and coloration characteristics of different types of Hanbok, so we can find the purpose far increasing understanding of various color beauty and coloration of today's Hanbok. The findings of this research are summarized as follows; 1. Traditional Hanbok coloration is influenced by the modern rotor and tone, and is apt to show the trend of emphasizing individuality. 2. Hanbok coloration of middle period in 2000's has become to use high value and chroma, giving more bright and luxurious impression then the early period. 3. For this study, we have categorized the total of 277 women's Hanboks by their coloration trends, through studying traditional Hanbok catalogues that enclosed vividly colored pure silk samples. As a result, it shows the order of contrary coloration(149), tone on tone coloration(56), similar coloration(23), monochrome coloration(20), tone in tone coloration(17), and 화학섬유chrome coloration(12). 4. Traditional, improved and living Hanbok show differences not only in their designs or materials but also in colorations. Using of traditional coloration is applied to traditional Hanbok and improved Hanbok in that order, and mostly the value and chroma of living Hanbok colorations are low, which emphasizes easiness to move and practicality.

• 천문학회보
• /
• 제39권1호
• /
• pp.61.1-61.1
• /
• 2014

GSH 006-15+7 is a Milky Way supershell discovered by Moss et al. (2012). This supershell shows large shell-like structures in H I velocity maps. We have analyzed FUV emission for the supershell regions based on the FIMS and GALEX observations. Bright FUV flux at the boundaries of the supershell is mostly originated from dust scattering of FUV photons by dust clouds which was also observed at the boundaries of the supershell. We could find the distance to the supershell can be closer more than 30% compared with the distance of 1500 pc suggested by Moss et al. (2012) from the dust scattering simulation. And we also found the albedo and the phase function asymmetry factor of interstellar grains were 0.30 and 0.40, respectively. The confidence range for the albedo covers the theoretical value of 0.40, but g-factor is rather smaller than the theoretical value of 0.65. The small g-factor might mean the environment of turbulent ISM of the supershell. Meanwhile, the excess of C IV and X-ray emissions in the inside of the supershell can support the existence of hot gas and cooling in the supershell. And the C IV and X-ray emissions are monotonically decrease as away from the center of the SNR. This indicates the size of the hot bubble has considerably shrunk. We applied a simple simulation model to the PDR candidate region of the lower part of the supershell and obtained a H2 column density N(H2) = 1017.0-18.0 cm-2 and total hydrogen density nH ${\geq}$ 10 cm-3. This result shows the PDR candidate region represents a transition region from the warm phase to the cool phase in the PDR.