• Title/Summary/Keyword: IR-UV

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Determining the star formation rate of type 2 AGNs with multi-wavelength SED from UV to radio

  • Lee, Jeong Ae;Woo, Jong-Hak
    • The Bulletin of The Korean Astronomical Society
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    • v.43 no.1
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    • pp.61.1-61.1
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    • 2018
  • Outflows are common among local AGNs. Woo et al. (2017) suggested that AGN feedback through outflows is delayed by a dynamical time scale before the suppression of SFR is observationally detected. However, these SFR have large uncertainties because they were estimated by Artificial Neural Network (ANN) method (Ellison et al. 2016). We measured the SFR of 21 far-IR matched sources (z < 0.1) with total IR luminosity from multi-wavelength SED fitting from UV to radio. 15 out of 21 sources were observed with JCMT SCUBA-2 450 and 850um and 4 and 2 sources were matched with archival data of JCMT SCUBA-2 and Herschel SPIRE, respectively. We compared the true SFR by SED fitting with ANN-based one. In addition, we confirmed that sub-mm data are important to determine the SFR with total IR luminosity from SED fitting. Finally, we discuss the significance of true SFR and further the AGN-SF link.

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Dust Radiative Transfer Model of Spectral Energy Distributions in Clumpy, Galactic Environments

  • Seon, Kwang-il
    • The Bulletin of The Korean Astronomical Society
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    • v.43 no.2
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    • pp.52.2-52.2
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    • 2018
  • The shape of a galaxy's spectral energy distribution ranging from ultraviolet (UV) to infrared (IR) wavelengths provides crucial information about the underlying stellar populations, metal contents, and star-formation history. Therefore, analysis of the SED is the main means through which astronomers study distant galaxies. However, interstellar dust absorbs and scatters UV and optical light, re-emitting the absorbed energy in the mid-IR and Far-IR. I present the updated 3D Monte-Carlo radaitive transfer code MoCafe to compute the radiative transfer of stellar, dust emission through a dusty medium. The code calculates the emission expected from dust not only in pure thermal equilibrium state but also in non-thermal equilibrium state. The stochastic heating of very small dust grains and/or PAHs is calculated by solving the transition probability matrix equation between different vibrational, internal energy states. The calculation of stochastic heating is computationally expensive. A pilot study of radiative transfer models of SEDs in clumpy (turbulent), galactic environments, which has been successfully used to understand the Calzetti attenuation curves in Seon & Draine (2016), is also presented.

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Chemical Modification and Functionalisation of Poly(ethylene terephthalate) Fiber (폴리에틸렌테레프탈레이트 섬유의 화학개질 및 기능화)

  • 김인회;김성희
    • Polymer(Korea)
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    • v.26 no.3
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    • pp.389-399
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    • 2002
  • Poly (ethylene terephthalate) (PET) fibers were modified by deep UV irradiation which was produced by a low pressure mercury lamp. FT-IR and XPS analyses were used to elucidate the surface chemical composition of PET fibers treated with UV. Relative $O_{1s}$ intensity increased considerably and it was found that oxygen was incorporated in the form of COO on the fiber surface. FT-IR and XPS analyses proved the existence of carboxylic groups on the surfaces and the adsorption test of cationic compound further supported these results. The concentration of carboxylic acid group on the surface increased remarkably with Increasing irradiation time. XPS analysis and adsorption experiments proved that the surface structure of the UV-irradiated PET fibers were stable for 12 months. Antibacterial property and the deodorization rate of UV-irradiated PET fibers adsorbed with the berberine compound were investigated. Reduction rates of bacteria increased by about 21 to 99% compared to unradiated PET fiber. Deodorization rates of 23% for unradiated PET fiber increased to about 75% for 30 min irradiated samples.s.

Characterization of Selectively Absorbing Properties of Indium Tin Oxide Thin Films by UV-VIS-IR Spectroscopy (UV-VIS-IR 분광법에 의한 산화 인듐 주석 박막의 선택적 투과 흡수 특성 관찰)

  • Lee, Jeon-Kook;Lee, Dong-Heon;Cho, Nam-Hee
    • Analytical Science and Technology
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    • v.5 no.1
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    • pp.135-142
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    • 1992
  • Indium tin oxide(ITO) films coated on the window glass selectively transmit the solar energy and infrared. We call this system passive solar collectors. Selectively absorbing properties of sol gel dip coated ITO films were characterized by UV-VIS-NIR spectroscopy. The effects of heat treating temperature, time, atmosphere, substrate and barrier layers are concerned. Indium tin oxide films heat-treated at $500^{\circ}C$ in a reducing atmosphere show intrinsic properties. Efficiency of solar energy transmittance was enhanced by coating of $SiO_2-ZrO_2$ as an alkali ion barrier layer. Energy was saved by the double layers of $SiO_2-ZrO_2$ and ITO since solar energy is transmitted and heat generated inside(${\lambda}$ > 2700nm) is reflected.

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Preparation of the Polymers Containing Phenylamide and Dimethylaminoethyl Groups and their Properties as a Nagative Photoresist

  • Chae, Kyu-Ho;Kang, Jin-Koo;Kim, Su-Kyung;Chough, Sung-Hyo
    • Journal of Photoscience
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    • v.7 no.2
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    • pp.47-52
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    • 2000
  • The copolymmers of N, N-dimethylaminoethyl methacrylate(DAEM) and N-arylmethacrylamide (AMA) were prepared, and their photochemical properties as a negative photoresist were studied by the measurements of insoluble fraction, and by UV and IR absorption spectral changes. These copolymers are soluble in DMF, actone, methanol, of acidic buffer solutions. Solubility of these copolymer films in the vuffer solutions increased with the amount of DAEM units in the copolymer and decreased with the pH value. The insoluble fraction of the copolymer films in the buffer solution of pH 4 of in methanol increased with irradiation time and the amount of AMA units in the copolymer. UV and IR spectral changes indicated that not only photo-crosslinking but also the photo-Fries rearrangement took place upon irradiation with a 254nm UV light.

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Study on the Components of Glehniae Radix (해방풍의 성분연구)

  • Seo, Yoon-Kyo;Ryu, Kyung-Soo
    • Korean Journal of Pharmacognosy
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    • v.7 no.4
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    • pp.233-235
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    • 1976
  • Substances $I{\sim}VII$ are isolated from the root of Glehnia littoralis which has been often used as a subsitute of Bang-Poong in Korea. White needle crystalline substance of $C_{29}H_{50}O$, m.p. $137{\sim}139^{\circ}C$ was confirmed as ${\beta}-sitosterol$ through elemental analysis, derivative synthesis, IR and physicochemical tests. Moreover, it was concluded that white needle crystal of $C_{12}H_{8}O_{4}$, m.p. $188{\sim}189^{\circ}$ was confirmed as bergapten, through a contrast test with standard substance and by UV and IR-spectra. It was found that substance III and VII coincided with the Rf values of imperatorin and umbelliferone and to its colors under the UV-ray, and its similarity to UV-spectrum can be recognized, but their melting points are remarkedly different respectively.

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Iodine doping effect of $\sigma$ -conjugate poly(methyl-phenylsilene). ($\sigma$-공액 고분자 poly(methyl-phenylsilyene)의 요오드 도핑효과 연구)

  • ;;S. Nespurek
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.11a
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    • pp.145-148
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    • 2000
  • In contrast to the $\pi$ -conjugated polymers which typically absorb light only in the visible spectral region, the $\sigma$-conjugated polymers can be used as efficient material absorbing light in the UV region. In this work, the electronic and optical properties of I$_2$-doped $\sigma$ -conjugated poly (methyl-phenylsilylene) (PMPSi) polymer were investigated. DC conductivity up to 1.2$\times$10$^{-4}$ S/cm was obtained by I$_2$-doping. In UV/Vis absorbance spectrum, a new peak was observed near 370 nm, which was explained by polaron model. The photoluminescence (PL) intensity decreased with increasing degree of I$_2$-doping, and the Infrared (IR) spectrum analysis revealed that the dopants are not directly coupled to the polymer, but effect motions of the methyl and phenyl groups.

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Multi-spectral Flash Imaging using Region-based Weight Map (영역기반 가중치 맵을 이용한 멀티스팩트럼 플래시 영상 획득)

  • Choi, Bong-Seok;Kim, Dae-Chul;Lee, Cheol-Hee;Ha, Yeong-Ho
    • Journal of the Institute of Electronics and Information Engineers
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    • v.50 no.9
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    • pp.127-135
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    • 2013
  • In order to acquire images in low-light environments, it is usually necessary to adopt long exposure times or resort to flash lights. However, flashes often induce color distortion, cause the red-eye effect and can be disturbing to subjects. On the other hand, long-exposure shots are susceptible to subject-motion, as well as motion-blur due to camera shake when performed hand-held. A recently introduced technique to overcome the limitations of traditional low-light photography is that of multi-spectral flash. Multi-spectral flash images are a combination of UV/IR and visible spectrum information. The general idea is that of retrieving details from the UV/IR spectrum and color from the visible spectrum. However, multi-spectral flash images themselves are subject to color distortion and noise. This works presents a method to compute multi-spectral flash images so that noise can be reduced and color accuracy improved. The proposed approach is a previously seen optimization method, improved by the introduction of a weight map used to discriminate uniform regions from detail regions. The weight map is generated by applying canny edge operator and it is applied to the optimization process for discriminating the weights in uniform region and edge. Accordingly, the weight of color information is increased in the uniform region and the detail region of weight is decreased in detail region. Therefore, the proposed method can be enhancing color reproduction and removing artifacts. The performance of the proposed method has been objectively evaluated using long-exposure shots as reference.

IR Absorption Property in Nano-thick Ir-inserted Nickel Silicides (이리듐이 첨가된 니켈실리사이드의 적외선 흡수 특성)

  • Yoon, Kijeong;Song, Ohsung;Han, Jeungjo
    • Korean Journal of Metals and Materials
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    • v.46 no.11
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    • pp.755-761
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    • 2008
  • We fabricated thermally evaporated 10 nm-Ni/1 nm-Ir/(poly)Si films to investigate the energy saving property of silicides formed by rapid thermal annealing (RTA) at the temperature range of $300{\sim}1200^{\circ}C$ for 40 seconds. Moreover, we fabricated 100 nm-thick ITO/(poly)Si films with an rf-sputter as references. A transmission electron microscope (TEM) and an X-ray diffractometer were used to determine cross-sectional microstructure and phase changes. A UV-VIS-NIR and FT-IR (Fourier transform infrared spectroscopy) were employed for near-IR and middle-IR absorbance. Through TEM analysis, we confirmed 20~65 nm-thick silicide layers formed on the single and polycrystalline silicon substrates. Ir-inserted nickel silicide on single crystalline substrate showed almost the same absorbance in near IR region as well as ITO, but Ir-inserted nickel silicide on polycrystalline substrate, which had the uniform absorbance in specific region, showed better absorbance in near IR region than ITO. The Ir-inserted nickel silicide on polycrystalline substrate particularly showed better absorbance in middle IR region than ITO. The results imply that nano-thick Ir-inserted nickel silicides may have excellent absorbing capacity in near-IR and middle-IR region.

Characterization and Synthesis of Titanium (IV) Isopropoxide Derivatives (Titanium(IV) isoproxide 유도체의 합성 및 특성연구)

  • Jung, Mie-Won
    • Analytical Science and Technology
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    • v.12 no.6
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    • pp.509-514
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    • 1999
  • The systematic modification of titanium(IV) isopropoxide with acetic acid as a organic additive was done and identifided by FT-IR, $^1H$, $^{13}C$ NMR and UV-Vis spectroscopy. The structure was cbanged after hydrolysis-condensation reaction and drying process. The hydrolysis-condensation rates of modified Ti alkoxide with acetic acid were investigated by $^1H$ NMR spectroscopy. This modified Ti(IV) alkoxide was less reactive toward hydrolysis-condensation reaction than $Ti(OPr^i)_4$, which can be attributed to the stable ligand structure between Ti alkoxide and ligand. The structural change on obtained from gel powders with heat treatment was also observed by FT-IR spectroscopy.

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