• Title/Summary/Keyword: Spectral studies

Search Result 691, Processing Time 0.032 seconds

Studies on the Constituents of the Stem Barks of Acanthopanax gracilistylus W. W. Smith

  • Liu, Xiang Qian;Chang, Seung-Yeup;Park, Sang-Yong;Nohara, Toshihiro;Yook, Chang-Soo
    • Natural Product Sciences
    • /
    • v.8 no.1
    • /
    • pp.23-25
    • /
    • 2002
  • Ten compounds were isolated from the stem barks of Acanthopanax gracilistylus WW Smith (AGS) by steam distillation, they were p-menta-1,5,8-triene, n-butyl isobutylphthalate, p-mentha-1,5-diene-8-ol, 8-hydroxy-p-cymene, myrtenol, trans-(+)-carveol, 1,3-di-tert-butylbenzene, 4-methyl-2,6-di-butylphenol, valencene and verbenone, respectively, characterized by GS-Mass spectra. And we have also extracted and isolated from the MeOH extracts of the stem barks of AGS, two compounds were obtained. On the basis of chemical and spectral evidence, they were syringin(l), ${\beta}-sitosterol(2)$.

DEVELOPING FOREST TYPE CLASSIFICATION METHODOLOGY USING KOMPSAT IMAGE BASED ON TASSELED CAP TRANSFORMATION

  • Kim, Sung-Jae;Jo, Yun-Won;Jo, Myung-Hee
    • Proceedings of the KSRS Conference
    • /
    • 2008.10a
    • /
    • pp.358-360
    • /
    • 2008
  • Recently there are many pilot studies for advanced application of first Korea national high resolution satellite image, which is called as KOMPSAT-MSC (Korean Multi-purpose Satellite-Multi-Spectral Camera), in Korea. In this study the forest type classification methodology is developed and its distribution map was constructed by applying high resolution satellite image, KOMPSAT-MSC, based on Tasseled Cap Transformation, especially through comparing the result of detailed filed surveying such as forest type, tree species, tree diameter, tree age and tree crown density in pilot study area.

  • PDF

SPECTRAL INDICES MEASURED BY PDS ON THE 4 DEGREE OBJECTIVE PRISM PLATE (4도 대물 프리즘 건판에서 PDS에 의한 스펙트럼 지수 측정)

  • Lee, Sang-Gak;Baek, Won-Geun;Hong, Seung-Su
    • Publications of The Korean Astronomical Society
    • /
    • v.8 no.1
    • /
    • pp.17-31
    • /
    • 1993
  • In order to check whether the 4-degree objective prism spectra can be used for deep spectroscopic studies of galactic structure, we measured the Rose(1984)'s seven indices between 3500 A and 4400 A for 19 Hyades stars on the Kiso Schmidt prism plate, K3496. By comparing the $4^{\circ}$-indices with those of Rose(1984), we have found that $H{\delta}/FeI$, $H{\gamma}/4325$, and P(3912)/P(CN) measured on the 4-degree prism spectra, are still useful for the derivation physical parameters.

  • PDF

POLARIZATION OF FIR EMISSION FROM T TAURI DISKS

  • Cho, Jung-Yeon;Lazarian, A.
    • Journal of The Korean Astronomical Society
    • /
    • v.40 no.4
    • /
    • pp.113-118
    • /
    • 2007
  • Recently far infra-red (FIR) polarization of the $850{\mu}m$ continuum emission from T Tauri disks has been detected. The observed degree of polarization is around 3 %. Since thermal emission from dust grains dominates the spectral energy distribution at the FIR regime, dust grains might be the cause of the polarization. We explore alignment of dust grains by radiative torque in T Tauri disks and provide predictions for polarized emission for disks viewed at different wavelengths and viewing angles. In the presence of magnetic field, these aligned grains produce polarized emission in infrared wavelengths. When we take a Mathis-Rumpl-Nordsieck-type distribution with maximum grain size of $500-1000{\mu}m$, the degree of polarization is around 2-3 % level at wavelengths larger than ${\sim}100{\mu}m$. Our study indicates that multifrequency infrared polarimetric studies of protostellar disks can provide good insights into the details of their magnetic structure.

3 차원 주화성 모델 개발을 통한 흡착형 세포의 동적특성 연구

  • Song, Ji-Hwan;Kim, Dong-Choul
    • Proceedings of the KSME Conference
    • /
    • 2008.11a
    • /
    • pp.1638-1642
    • /
    • 2008
  • Cell migration is one of the essential mechanisms responsible for complex biological processes. Intensive researches have begun to elucidate the mechanisms and search intriguing conditions for efficient control of cell migration. One general mechanism which is widely applicable for cells including neutrophil, Escherichia coli and endothelial cell is chemotaxis. Especially, understanding the chemotactic mechanics of cell crawling has important implications for various medical and biological applications. The single cell study for chemotaxis has an advantage over studies with the population of cells in providing a clearer observation of cell migration, which leads to more accurate assessments of chemotaxis. In this paper, we propose a three-dimensional model considering a single crawling cell to study its chemotaxis. The semi-implicit Fourier spectral method is applied for high efficiency and numerical stability. The simulation results reveal rich dynamics of cell.

  • PDF

Aristolactam Derivatives and Their N-Glycosides from Aristolochia contorta (청목향(靑木香)의 Lactam 배당체)

  • Lee, Heum-Sook;Han, Dae-Suk
    • Korean Journal of Pharmacognosy
    • /
    • v.24 no.1
    • /
    • pp.32-37
    • /
    • 1993
  • Phytochemical studies of the root of Aristolochia contorta afforded an unidentified N-glycoside rarely found in natural products. It's structure was elucidated as 8-desmethoxy-aristolactam $N-{\beta}-D-glucopyranoside$ by spectral data and chemical analysis. 6-Hydroxy-8-desmethoxy-aristolactam $N-{\beta}-D-glucopyranoside$, aristolactam I and aristolactam AII were also isolated from the same source. $^{13}C-NMR$ spectra were first assigned and the result confirmed N-C-O-glycosidic linkages in the glycosides.

  • PDF

Microbial Transformation of Two Prenylated Naringenins

  • Han, Fubo;Lee, Ik-Soo
    • Natural Product Sciences
    • /
    • v.23 no.4
    • /
    • pp.306-309
    • /
    • 2017
  • Microbial transformation of $({\pm})$-6-(1,1-dimethylallyl)naringenin (6-DMAN, 1) and $({\pm})$-5-(O-prenyl) naringenin-4',7-diacetate (5-O-PN, 2) was performed by using fungi. Scale-up fermentation studies with Mucor hiemalis, Cunninghamella elegans var. elegans, and Penicillium chrysogenum led to the isolation of five microbial metabolites. Chemical structures of the metabolites were determined by spectral analyses as $({\pm})$-8-prenylnaringenin (3), (2S)-5,4'-dihydroxy-7,8-[(R)-2-(1-hydroxy-1-methylethyl)-2,3-dihydrofurano]flavanone (4), $({\pm})$-5-(O-prenyl)naringenin-4'-acetate (5), $({\pm})$-naringenin-4'-acetate (6), and $({\pm})$-naringenin (7), of which 5 was identified as a new compound.

Intrinsic UV Reflection and Fluorescence Studies for Water Sorption in Polycarbonate, Polyurethane and Poly(Ethylene Terephthalate) Films

  • Kim Min Sun;Sung Chong Sook Paik
    • Fibers and Polymers
    • /
    • v.6 no.2
    • /
    • pp.127-130
    • /
    • 2005
  • Intrinsic UV reflection and fluorescence behaviors of polycarbonate, polyurethane and poly(ethylene terephthalate) films were investigated in order to characterize the interaction of water in these films. During water sorption process, UV reflection spectra of polycarbonate and polyurethane films showed little peak position changes. Fluorescence emission spectra of polycarbonate films showed red spectral shifts from 332 nm with water immersion time. This red-shifted peak could be due to phenyl-2-phenoxybenzoate, which is one of the major thermal degradation products in polycarbonate. Fluorescence peaks of polyurethane films appeared at two different positions and the ratio of these peak intensities increased with increasing immersion time. In the case of PET films, the UV reflection spectrum showed the peak intensity around 340 nm to change in response to water sorption. The fluorescence near 388 nm probably due to ground state dimer exhibited sensitivity with water sorption, when excited at 340 nm.

Optical and NIR Photometric Study of Star Clusters in IC10

  • Lim, Sung-Soon;Lee, Myung-Gyoon
    • The Bulletin of The Korean Astronomical Society
    • /
    • v.36 no.2
    • /
    • pp.144.2-144.2
    • /
    • 2011
  • A dwarf irregular galaxy IC10 in the Local Group is the nearest starburst galaxy, playing an important role revealing the details of starburst. It is located close to the Galactic plane so that it suffers from severe foreground reddening. Therefore much less is known about the property of this galaxy compared with other galaxies in the Local Group. So are star clusters in this galaxy. We present a photometric study of the star clusters in IC10. 57 star clusters are already found from HST images in previous studies, and we newly found 15 star clusters using Local Group Survey data and SUBARU/Suprime-Cam data. We derive UBVRI integrated photometry of these star clusters from the images from Local Group Survey data and JHKs photometry taken with SUBARU/MOIRCS. Then we derive age and mass of these clusters using the spectral energy distribution fitting with the simple stellar population models. We discuss the photometric and physical properties of these star clusters and its implication.

  • PDF

Development of Fast Imaging Solar Spectrograph and Observation of the Solar Chromosphere

  • Park, Hyung-Min
    • The Bulletin of The Korean Astronomical Society
    • /
    • v.36 no.2
    • /
    • pp.80.1-80.1
    • /
    • 2011
  • It is well known that chromospheric features are fine structured, short lived, and dynamic. Spectrograph-based observation have obvious advantage of getting physical properties of solar chromosphere than filter-based one. We developed and installed Fast Imaging Solar Spectrograph (FISS) attached on New Solar Telescope in Big Bear Solar Observatory. FISS have capabilities to take data with high time, spatial and spectral resolution at two wavelengths(Ha $6563{\AA}$ and CaII $8542{\AA}$) simultaneously. After FISS installation, we observed various chromospheric features : active regions, quiet regions, filaments/prominences and so on. As one of chromospheric studies, we analyzed solar prominences and got physical parameters by using simple radiative transfer modeling. The ranges of temperature and non-thermal velocities are found to be 7500-13000K and 5-11km/s, respectively.

  • PDF