• Title/Summary/Keyword: uv-spectra

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IUE ARCHIVAL SPECTRA OF 31 CYGNI

  • Kang, Young-Woon
    • Journal of Astronomy and Space Sciences
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    • v.8 no.1
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    • pp.53-61
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    • 1991
  • UV light curve of 31 Cygni has been made from the IUE high dispersion specta. The depth of primary minimum of the light curve is 5.2 magnitudes because the B4 star's steep spectral gradient. The light curve has been analyzed by the method of Wilson and Devinney Differential Correction (WD). The radial velocities have been measured using the Mg II h lines. The spectroscopic elements have been determined by the method of WD. The change of the Mg II resonance doublet has been investigated based on the eight representative spectra taken at well distributed orbital phases.

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ULTRAVIOLET FLUX VARIATION OF EPSILON AURIGAE

  • Kang, Young-Woon
    • Journal of Astronomy and Space Sciences
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    • v.7 no.1
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    • pp.57-69
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    • 1990
  • The eighteen ultraviolet light curves of Epsilon Aurigae have been plotted using the integrated fluxes reduced from the 233 IUE low dispersion spectra taken between 1978 and 1986. The times of contacts and depth of eclipse have been determined from the light curves at the wavelength from 2550 $AA$ to 3050 $AA$. The UV light curves show two brightenings during the totality, the downward slope of the variation from the second to the third contacts, and asymmetry of the eclipse light curve. The two selected spectra note that the energy density distribution is not changed between the totality of the eclipse and out-of-eclipse.

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Synthesis of New Bicyclic Aziridines Containing Chalcone Analogs and Investigation of Their Photochromic Properties

  • Besharati-Seidani, Tayebeh;Mahmoodi, Nosrat O.
    • Bulletin of the Korean Chemical Society
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    • v.34 no.3
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    • pp.875-883
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    • 2013
  • Ten new derivatives of 1,3-diazabicyclo[3.1.0]hex-3-enes linked via ether linkage to chalcones were synthesized and characterized by UV, FT-IR, $^1H$ NMR and $^{13}C$ NMR spectral techniques. The spectra of all synthesized compounds, confirmed structure-photochromic behavior relationships (SPBR) both in solution or in solid state by irradiation under UV light at 254 nm. In other efforts for first time photochromic behavior of ketoaziridines has been investigated.

The warm CO gas along the UV-heated outflow walls: a possible interpretation for the Herschel-PACS CO spectra of embedded YSO

  • Lee, Seokho;Lee, Jeong-Eun;Bergin, Edwin A.;Park, Yong-Sun
    • The Bulletin of The Korean Astronomical Society
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    • v.38 no.2
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    • pp.67.2-67.2
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    • 2013
  • Part of mid-J CO emission detected by the Herschel/PACS observations of embedded young stellar objects (YSOs) has been attributed to the UV-heated outflow walls. We have applied our newly developed self-consistent models of Photon Dominated Region (PDR) and Non-LTE line Radiative transfer In general Grid (RIG) to the Herschel FIR CO observations. If the black body radiation of T = 15,000 K is used, the observed mid-J CO line fluxes can be produced in inner dense regions (n ${\geq}$ 106 cm-3) with -4.5 ${\leq}$ log Gdust/n ${\leq}$ -2.5, where gas temperatures are larger than 300 K and CO abundances are ${\geq}$ 10-5, along the UV-heated outflow walls. The contribution of the UV heated outflow cavity wall in Class I seems to be larger than that in Class 0.

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Photodegradation of Phosphamidon and Profenofos (Phosphamidon과 Profenofos의 광분해성)

  • 민경진;차춘근
    • Journal of Environmental Health Sciences
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    • v.26 no.2
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    • pp.49-58
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    • 2000
  • The present study was performed to investigate photodegradation rate constants and degradation products of phosphamidon and profenofos by the USEPA method. The two pesticides were very stable in 16 days exposure of sunlight from September 3 to 22, 1999 and humic acid had no sensitizing effect on the photolysis of each pesticide in sunlight. In the UV irradiation test, phosphamidon was rapidly degraded as increasing UV intensity. In case of UV irradiation with TiO2 and with TiO2 powder amount, degradation of profenofos showed no significant difference with UV irradiation. Photodegradation rate of profenofos was slower than that of phosphamidon. In order to identify photolysis products, the extracts of degradation products were analyzed by GC/MS. The mass spectra of photolysis products of phosphamidon were at m/z 153 and 149, those of the profenofos were at m/z 208 and 240, respectively. It was suggested that the photolysis products of phosphamidon were 0, 0-dimethyl phosphate(DMP) and N, N-diethylchloroacetamide, those of profenofos were 4-bromo-2-chlorophenol and 0-ethyl-S-propyl phosphate.

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Color Characteristics of 3D-Printed TPU Material Applied with Ultra-Violet Curable Digital Printing Process (자외선 경화형 디지털 프린팅을 이용한 3D 프린팅 TPU 소재의 색채 특성)

  • Lee, Sunhee;Park, Soyeon;Jung, Imjoo;Lee, Jungsoon
    • Journal of the Korean Society of Clothing and Textiles
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    • v.45 no.6
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    • pp.1052-1062
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    • 2021
  • This study aims to confirm the possibility of Ultra-Violet (UV)-printed 3D printing materials using thermal polyurethane (TPU) with CMYK colors by applying an eco-friendly UV digital printing process. A UV-printed 3D printing TPU material was prepared with cycles of UV printing and CMYK colors. Dyeability of the 3D TPU samples with cycles of UV printing and CMYK were analyzed for thickness, weight, surface roughness, reflectance, colorimetry, and K/S values. The thickness and weight of 3D-printed TPU samples with cycles of UV printing are increased with overprints from 1 to 5. The surface roughness of 3D-printed TPU samples with increasing UV prints were decreased, meaning that the surface of TPU samples becomes gradually smoother. The reflectance spectra of CMYK UV-printed TPU samples showed the surface reflectance within each characteristic wavelength of CMYK. The 3D-printed TPU samples, subjected to UV printing twice or more, showed low surface reflectance. After examining the L*a*b* of the 3D-printed TPU samples by the cycles of UV printing, the study found that the more UV got printed more than 2 times, the closer the color to each CMYK.

The Effect of Acidic pH on the Spectral Properties of Bacteriorhodopsin (산성 pH가 박테리오로돕신의 분광학적 성질에 미치는 효과)

  • Quae Chae
    • Journal of the Korean Chemical Society
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    • v.23 no.5
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    • pp.320-324
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    • 1979
  • Purple membrane from Halobacterium halobium was incorporated into 7.5% polyacrylamide gels. Absorption and circular dichroic spectra of purple membrane incorporated with gels were obtained at various pH. The spectra of these gels measured at pH 7.0 were essentially identical with those obtained in the aqueous suspension of purple membrane. Acid titration of the gels showed the transition to a form absorbing at 605nm $(bR_{605}^{acid}$) at pH 2.6, and to a second form at 565nm $(bR_{565}^{acid})$ at pH 0.8. Dark-adapted gels showed an isosbestic point for each transition whereas light-adapted gels did not. Visible CD spectra of $bR_{570}^{LA},\;bR_{305}^{acid}\;and\;bR_{565}^{acid}$ all showed the typical bilobed pattern. CD spectra measured at UV wavelength region were also independent of the variation of pH in terms of molar ellipticity and spectral shape. The protonated species $bR_{605}^{acid}$ may be one of the intermediates formed during the normal photochemical cycle of purple membrane. Most probably, the species $bR_{605}^{acid}$ is considered to be $O^{640}$ in the cycle.

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Physicochemical Characteristics and Pharmacokintics of Ibuprofen Lysine Salts (흰쥐에서 이부프로펜 리신염의 물리화학적 특성 및 약물동태에 관한 평가)

  • Shin, Dae-Hwan;Kim, Tai-Sung;Park, Seong-Hyeok;Kim, Si-Hyun;Jo, Han-Jun;Han, Kun;Chung, Youn-Bok
    • YAKHAK HOEJI
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    • v.55 no.3
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    • pp.260-266
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    • 2011
  • Two types of water soluble lysine salts of ibuprofen were prepared and evaluated. Physicochemical properties for ibuprofen-l-lysinate (IBL-l), ibuprofen-dl-lysinate (IBL-dl) and ibuprofen (IB) were studied on melting point, specific ratation, UV spectra and $^1H$-NMR spectra. There were not differences between IBL-dl and IBL-l in UV spectra and $^1H$-NMR spectra. The pharmacokinetic parameters of IB were compared to those of its lysine salts (IBL-l and IBL-dl) after i.v. or oral administration at the dose of 50 mg/kg (calculated as IB). Total body clearance ($CL_t$) and area under the plasma concentration-time curve (AUC) were not different between IB group and IBL groups after i.v. administration. On the other hand, IBL-l and IBL-dl produced peak plasma concentrations ($C_{max}$) significantly ealier and higher than IB. Time to reach peak concentration ($T_{max}$) after IBL administration was lower than that after IB administration. There was no difference in AUC across all different groups (IB, IBL-l and IBL-dl) after oral administration. However, absorption rate constant ($k_a$) of IBL-l and IBL-dl were significantly increased than that of IB. These results indicated that the administration of IBL-l and IBL-dl may be advantageous if rapid and reliable onset of pain relief is required.

Encapsulation of 2,4-Dihydroxybenzophenone into Dodecylbenzenesulfonate Modified Layered Double Hydroxide for UV Absorption Properties

  • Li, Shifeng;Shen, Yanming;Liu, Dongbin;Fan, Lihui;Wu, Keke
    • Bulletin of the Korean Chemical Society
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    • v.35 no.2
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    • pp.392-396
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    • 2014
  • New organic-inorganic composite of 2,4-dihydroxybenzophenone (BP-1) encapsulation into dodecylbenzenesulfonate (DBS) modified layered double hydroxide (LDH) was successfully prepared. The surface, structural, thermal and absorption properties of the BP-1/DBS-LDH nanohybrid was characterized by BET analysis, scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TG) and diffuse reflectance UV-Vis absorbance spectra (DRUV-vis). The interlayer configuration of composite and the adsorption mechanism of BP-1 on MgAl-DBS-LDH were discussed. It was suspected that DBS anions located in the form of monolayer arrangement with a $75^{\circ}$ anti parallel angle between dodecylbenzenesulfonate chain axis. The diffuse reflectance UV-Vis absorbance results revealed that the UV absorbing wavelength of BP-1/DBS-LDH evidently extends to about 400 nm, which shows that the BP-1/DBS-LDH has the potential application as a UV absorber.

Impacts of Ultraviolet-B Radiation on Rice-Field Cyanobacteria

  • Sinha, Rajeshwar P.;Hader, Donat-P.
    • Journal of Photoscience
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    • v.9 no.2
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    • pp.439-441
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    • 2002
  • Cyanobacteria are the dominant micro flora in rice-fields, contributing significantly to fertility as a natural biofertilizer. Recent studies show a continuous depletion of the stratospheric ozone layer, and the consequent increase in solar UV-B (280-315 nm) radiation reaching the Earth's surface. UV-B radiation causes reduction in growth, survival, protein content, heterocyst frequency and fixation of carbon and nitrogen in many cyanobacteria. UV -B induced bleaching of pigments, disassembly of phycobilisomal complexes, thymine dimer formation and alterations in membrane permeability have also been encounterd in a number of cyanobacteria. However, certain cyanobacteria produce photoprotective compounds such as water soluble colorless mycosporine-like amino acids (MAAs) and the lipid soluble yellow-brown colored sheath pigment, scytonemin, to counteract the damaging effects of UV-B. Cyanobacteria, such as Anabaena sp., Nostoc commune, Scytonema sp. and Lyngbya sp. were isolated from rice fields and other habitats in India and screened for the presence of photoprotective compounds. A circadian induction of the synthesis of MAAs by UV -B was noted in a number of cyanobacteria. Polychromatic action spectra for the induction of MAAs in Anabaena sp. and Nostoc commune also show the induction to be UV-B dependent peaking at 290 nm. Another photoprotective compound, scytonemin, with an absorption maximum at 386 nm (also absorbs at 300, 278, 252 and 212 nm), was detected in many cyanobacteria. In conclusion, a particular cyanobacterium having photoprotective compounds may be a potent candidate as biofertilizer for crop plants.

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