• 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.

• Bulletin of the Korean Space Science Society
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• 2008.10a
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• pp.31.2-31.2
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• 2008

We present the results offar ultraviolet (FUV, 1350-1750 ${\AA}$) auroral observations made by the Far-ultraviolet IMaging Spectrograph (FIMS) instrument on the Korean microsatellite STSAT-1. The instrument was capable of resolving spatial structures of a few kilometers with the spectral resolution of 2-3 ${\AA}$. The observations were carried out simultaneously with the measurement of precipitating electrons using an electrostatic analyzer (ESA, 100 eV-20 keV) and a solid state telescope (SST, 170 keV-360 keV) on board the same satellite. With a careful mapping of the field lines, we were able to correlate the particle spectrum to the corresponding FUV spectrum of the footprints of the FIMS image that varied significantly in fine scales. We divided the FIMS spectral band into the LBH long (LBHL, 1640-1715 ${\AA}$) and LBH short (LBHS, 1380-1455 ${\AA}$) bands, and compared the electron energies with the intensities of LBHL and LBHS for the well-defined inverted-V structures. The result shows a strong correlation between the total LBH intensity and the energy flux measured by ESAwhile the peak energy itself does not correlate well with the LBH intensity. On the other hand, it was observed that the ratio of the LBHL intensity to that of LBHS increased significantly as the peak electron energy increased, primarily due to a smaller absorption by O2 at LBHL than at LBHS.

• Journal of the Korean Society of Clothing and Textiles
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• v.35 no.2
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• pp.218-229
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• 2011

Dyeing properties of cotton and ramie fabrics with pine needles colorants were studied by investigating the analysis of pine needles colorants, the effect of dyeing conditions (such as dye concentration, dyeing temperatures and times on dye uptakes), effect of mordants, and color change. The various colorfastness of dyed fabrics were evaluated for practical use; in addition, the antimicrobial ability, ultraviolet-cut ability, and deodorant ability were estimated. In the UV-Visible spectrum, the wavelength of the maximum absorption for pine needles extract was 285nm, and pine needles colorants produced a yellow color. From FT-IR and GC-MS results, it was assumed that chromophoric substance from pine needles extracts were mixed with flavonol tannin and flavanol tannin. An increased dyeing concentration resulted in a larger dye uptake and a Freundlich absorption isotherm was obtained. A larger dye uptake occurred as the dyeing time and temperature increased. Post-mordanting was more effective than pre-mordanting and the dye uptake of fabrics improved by mordanting. The colorfastness of dyed fabrics showed a low rating; however, colorfastness to washing and dry cleaning of cotton fabrics mordanted with N.Cu, and friction fastness of ramie fabric mordanted with Cu improved. The dyed fabrics showed very good antimicrobial abilities of 99.9%. In addition, the ultraviolet-cut ability and deodorant ability improved in fabrics dyed with pine needles extracts.

• Journal of the Korean Society of Clothing and Textiles
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• v.35 no.2
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• pp.206-217
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• 2011

The dyeing properties of cotton fabrics with bamboo colorants were studied by investigating the analysis of bamboo colorants, the effect of dyeing conditions (dye concentrations, dyeing temperatures and times on dye uptakes), effect of mordants, and color change. The various colorfastness of dyed fabrics were evaluated for practical use; in addition, the antimicrobial ability, ultraviolet-cut ability, and deodorant ability were also estimated. In the UV-Visible spectrum, the wavelength of the maximum absorption for bamboo stems and leaves extracts was found to be 280nm and 295nm, respectively; in addition, bamboo colorants produced a yellow color. From the FT-IR and GC-MS results, it was assumed that the chromophoric substance from bamboo extracts was composed of flavones substances with tricin. An increased dyeing concentration resulted in a larger dye uptake and a Freundlich absorption isotherm was obtained. A larger dye uptake occurred as the dyeing time and temperature increased. The post-mordanting was more effective than pre-mordanting. Mordants, Fe and N.Fe, were effective for an increased dye uptake. The color of fabrics mordanted with Cu and N.Cu changed to GY. Regardless of mordanting, the colorfastness on the washing of dyed fabrics showed a low rating compared to other fastness. Mordanting adversely affected the lightfastness of dyed fabric. The dyed fabric showed very good antimicrobial abilities of 99.9%. In addition, the ultraviolet-cut ability and deodorant ability improved in cotton fabric dyed with bamboo extracts.

• Journal of the Korean Solar Energy Society
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• v.22 no.4
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• pp.44-50
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• 2002

Photosynthesis of plants is effective in the range of 550 to 700 nm of the wavelength of solar irradiation. If the conversion of ultraviolet to the above mentioned region is possible, the photosynthesizing ability is expected to be enhanced. $Eu^{3+}$ doped soda-lime bulk and $TiO_2-SiO_2$ sol-gel coated glasses were prepared and their spectroscopic properties were studied. The absorption and emission spectra for the specimens were measured with the changes of wavelength and Eu ion concentration in the range of the wavelength of 300 to 700nm. The transmittance intensity of visible light through the bulk glass and the coated one was unchanged with the addition of Eu element. The emission spectrum intensity of $Eu^{3+}$ was found to be the maximum at 618 nm which is a transition of $^5DO{\rightarrow}^7F_2$. Additionally, it was shown that the intensity was linearly increased up to 10% of the Eu concentration.

• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.220-221
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• 2003

Intracavity second harmonic generation of diode pumped solid state lasers in the visible and ultraviolet regions provide efficient, compact and robust light sources for various applications, such as optical data storage, material processing, spectroscopy and bioanalysis. Advantages of neodymium vanadate (Nd：$YVO_4$) as a gain medium for intracavity-doubled lasers over Nd：YAG lie in the facts that the gain spectrum consists of a single line with short absorption depth, and that the stimulated emission cross sections are larger. (omitted)

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.455-455
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• 2013

$CeO_2$ nanorings were synthesized by using a surfactant free hydrothermal method. The surface morphology, structural and optical properties of the synthesized $CeO_2$ was investigated by using scanning electron microscopy (SEM), X-ray diffraction (XRD), and ultraviolet-visible (UV) spectroscopy measurements. SEM images showed that the surface morphology of the formed $CeO_2$ appeared as nanorings. The XRD pattern of $CeO_2$ nanorings showed the presence of the polycrystalline $CeO_2$ phase readily indexed to the cubic fluorite structure of the $CeO_2$. The mean crystallite size of the $CeO_2$ was calculated using the Scherrer equation from the XRD line broadening of the (111) planes of the cubic $CeO_2$. The UV-Visible spectroscopy spectrum of the $CeO_2$ nanorings exhibited a strong UV absorption band around 350 nm.

• International journal of advanced smart convergence
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• v.8 no.3
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• pp.27-38
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• 2019

I reviewed about dyeing fastness and functional properties of the non-mordant dyed cotton and iron mordant dyed cotton with astringent persimmon juice. In the UV-VIS spectrum of astringent persimmon juice, the maximum absorption wavelength of the juice was 272.0 nm, which was a characteristic peak of tannin. In dyeing fastness, light fastness of the non-mordant dyed cotton was a little low at grade 2~3. But by the iron mordant treatment, the light fastness was good at grade 4. Dry cleaning fastness to discoloration and contamination was excellent at grade 4~5 for both the non-mordant dyed cotton and iron-mordant dyed cotton. Their rub fastness were grade 3 and grade 2~3 respectively, in the dry condition, and grade 2~3 and grade 3 respectively, in the wet condition. In the perspiration fastness of the non-mordant dyed cotton, the discoloration from acidity and alkalinity was grade 3~4 and grade 3, respectively, and contamination from acidity and alkalinity was relatively good at grade 4. Meanwhile, in the perspiration fastness of the non-mordant dyed cotton, discoloration from acidity and alkalinity was fair, both recording grade 3~4, and contamination from acidity and alkalinity was very good, both recording grade 4~5. In the ultraviolet protection effect of the non-mordant dyed cotton and iron-mordant dyed cotton, the ultraviolet protection factor was both 50+, both of which showed an excellent ultraviolet blocking effect. And the protection rate of UV-A appeared 98.4% and 99.1%, respectively, and the protection rate of UV-B showed 98.7% and 99.2, respectively. In addition, both exhibited an excellent deodorization rate over 99.9% or more, irrespective of the passage of time. Also, both showed an excellent antimicrobial activity over 99.9% or more against Staphylococcus aureus and Klebsiella pneumoniae.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.1
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• pp.60-66
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• 1997

The characteristics and stability of pigments produced by Monascus anka in a jar fermenter were examined The pigments produced by the mold were fractionated into four pigments, i.e., extracellular red pigment(ERP) extracellular yellow Pigment(EYP), intracellular red pigment(IRP) and intracellular yellow pigment(IYP) by the solvent fractionation method. These pigments showed characteristic absorption spectrum indicating that they were composed of different components of pigments. Each of these four pigments separated from Monascus anka were stable under ultraviolet light, fluorescent light and in dark conditions, but their color was faded rapidly under sun light. They were also very stable against temperature below 8$0^{\circ}C$, above which temperature the stability of the Pigments was decreased rapidly. Among the eight organic acids tested, tartaric and citric acids were found to be detrimental against the Monascus anka Pigments. And Cu$^{2+}$ ion showed the most deleterious effect on the color change of the pigments.s.

• Journal of the Korean Chemical Society
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• v.37 no.3
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• pp.287-293
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• 1993

Ultraviolet spectrophotometric investigation has been carried out on the system of charge-transfer(CT) complex with iodine and tetramethyltin in n-hexane and acetone. From these results, the transient CT absorption spectrum can be observed and the subsequent disappearance of CT absorption spectrum is accompained by the cleavage of tetramethyltin with iodine (iododestannylation). Therefore, the rate constants for the iododestannylation were determined at 10, 25 and 35$^{\circ}C$ up to 1600 bar and the rates of reaction were increased with increasing temperature and pressure. From these rate constants, the values of the activation parameters (${\Delta}V^{\neq}$, ${\Delta}{\beta}^{\neq}$, ${\Delta}H^{\neq}$ and ${\Delta}S^{\neq}$) were obtained and discussed in terms of solvent structure variation of transition state and mechanism from these values. It could postulated that the reaction is followed with S$_F$2 mechanism and weakened S$_F$2 mechanism nature by increasing pressure.