• Journal of Photoscience
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• v.9 no.2
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• pp.454-456
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• 2002

It is important to determine the action spectrum of UV-B radiation contained in the sunlight to estimate the risk of skin cancer. We have investigated action spectra for induction of apoptosis and reproductive cell death in L5178Y cells using the Okazaki Large Spectrograph at NIBB. L5178Y cells were exposed to light at different wavelengths in UV-B or UV-A region. Frequencies of apoptosis induction and reproductive cell death were determined by counting cells with chromatin condensation, and by the colony formation assay, respectively. The measured sensitivity spectra for the two end-points were in very good agreement. Sensitivity decreased steeply with increase of wavelength in UV-B region and remains nearly constant in UV-A region. The action spectra were also slightly steeper than that for the minimum erythematic dose (MED), but very similar to the light absorption spectrum of DNA in UV-B region. On the other hand, the spectra for both endpoints were similar to MED spectrum but not DNA spectrum in the UV-A region. Also different time-course and morphological difference of apoptosis were found between UV-B (long time, fragmentation) and UV-A (short time, shrinkage) region. These results suggest that DNA damage induced by UV-B light triggers apoptosis and reproductive cell death, but other damaged targets (membrane, protein and so on) trigger these effects in UV-A region.

• Journal of the Korean Wood Science and Technology
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• v.15 no.4
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• pp.26-31
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• 1987

The ultraviolet and infrared spectra of dioxane lignin from bamboo were investigated. 1. Spectrum curve type considerably resembled that of wood lignin. There were 3 absorption peak positions at 210nm(max. peak), at 260-270nm(shallow mini. peak), at 280nm(lower max. peak) as in the wood lignin spectra. 2. The lower minimum peak near at 280 nm is the typical peak of lignin. This peak does not exist exactly at 280 nm but from 282nm to 285nm in this bamboo UV spectra. The absorption intensities are equal in this region and the peak is not sharp. 3. The absorption band of aromatic nucleus is near at wave number $1550cm^{-1}$ in the IR spectra of bamboo lignin. The intensity at about 1040-$1130cm^{-1}$ and at about 1230-$1275cm^{-1}$ were similar in the hardwood lignin but reverse to that of softwood lignin spectrum.

• Proceedings of the Acoustical Society of Korea Conference
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• 1992.06a
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• pp.43-48
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• 1992

In the area of speech vocoder systems, the MBE vocoder allows the high quality and low bit rate. In the MBE parameters detection, the dicision methods of V/UV region proposed until now are dependent highly to the other parameters, fundamental frequency and formant information. In this paper, thus, we propose a new V/UV detection method that uses a zero-crossing rate of flatten harmonices spectrum. This method can reduce the influences of the other parameters for the V/UV regions detection.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.11
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• pp.743-750
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• 2012

An ultraviolet (UV) absorption method has a difficulty to analyze $ClO_{2(aq)}$ in solutions containing various chlorine species because UV spectrum of $ClO_{2(aq)}$ overlaps with other chlorine-containing species. This study has proposed the deconvolution method of UV spectrum to analyze $ClO_{2(aq)}$ concentration quantitatively in solution containing various chlorine species. We compared results obtained from UV deconvolution method with titration method. Good agreement of $ClO_{2(aq)}$ concentration between them has been shown in about 10%. This result informs us that the deconvolution method of UV spectrum could be a feasible for the analysis of $ClO_{2(aq)}$ in solution containing various chlorine species.

• Journal of Advanced Navigation Technology
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• v.11 no.1
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• pp.87-92
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• 2007

The conventional CELP(code excited linear prediction) type vocoder has no V/UV(voiced/unvoiced) classifier. So, the unvoiced speech is processed like the voiced speech. In this paper, to reduce the bit rate, we propose a new V/UV decision algorithm minimized error rate and preprocessing computation. This V/UV classifier use the LSP(line spectrum pair) parameter which is acquired spectrum analysis process in CELP vocoders. Applying this method to the 5.3kbps ACELP(algebraic code excited linear prediction) in the G.723.1, we can get the transmission bits rate reduction of 6% approximately without degradation of speech quality.

• Korean Journal of Food Science and Technology
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• v.37 no.3
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• pp.360-363
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• 2005

To detect falcarinol in Acanthopanax senticosus, its stem and bark were extracted with methanol fractionated with petroleum ether and diethyl ether, and separated by silica gel column chromatography, Resulting six crude samples were compared with standard falcarinol through TLC on silica gel plates. Fraction 6 showed $R_{f}$ value of 0.46 similar to that of standard falcarinol. Through analytical reverse phase HPLC/PDA, UV spectra of standard falcarinol and traction 6 recorded between 200 and 340 nm showed identical peaks and UV spectra patterns. GC/MS revealed standard falcarinol and fraction 6 have equal retention times of 7.4 and 8.5 min before and after TMS-derivatization, respectively. Standard falcarinol and fraction 6 showed more similar spectrum patterns after TMS-derivatization than before. These results confirm presence of falcarinol in A. senticosus.

• The Korean Journal of Food And Nutrition
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• v.7 no.4
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• pp.332-337
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• 1994

The antioxidant activity of solvent extracts isolated from barley leaves was investigated by measuring peroxide value. The fractions of methanol extract obtained from preparative TLC was also studies, with UV-Visible spectrum, total phenol contents and hydrogen donating ability(HDA) The antioxidant activity of various solvent extracts was, in decreasing order, methanol> ethyl ether> methylene chloride $\geq$ ethyl acetate $\geq$acetone> hexane. The antioxidant activity of the fractions of methanol extract was, in decreasing order, fraction 2> fraction 3> fraction 1 and their activity was all superior to that of tocopherol at 500 ppm level. All fraction(1, 2 and 3) exhibited a strong UV absorption at 280 m which would be specifically produced by phenolic compound. UV absorption at 280 m of fraction 2 was greater than those of fraction 1 and 3. In the visible spectrum of these fractions, the maximum .absorption wavelengths of fraction 1, 2 and 3 were 660, 460 and 460 m, respectively. Antioxidant activity of barley leaves seemed to be due to the flavonoids containing phenolic group by UV spectrum and total phenol content.

• Bulletin of the Korean Chemical Society
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• v.32 no.9
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• pp.3443-3447
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• 2011

The spectroscopic behavior of catechin (5,7,3',4'-tetrahydroxyflavan-3-ol), has been studied in the presence and the absence of air using UV-vis absorption spectrophotometry and fluorescence spectroscopy. The UV-vis absorption spectrum of catechin shows a very sharp and strong absorption maximum peak at 275 nm in deaerated water. New absorption maximum peaks appeared in aerated water, as well as in basic aqueous solution, caused by the oxidation of catechin. The absorbances in the UV-vis absorption spectrum of catechin decreased when the solution was left in the dark for a long time. The fluorescence emission spectrum of catechin after a long time period differs markedly from that in freshly prepared solution; the fluorescence maxia shifted as time passes after adding catechin to the solutions. When the deaerated basic catechin solutions were left in the dark for a long time, their fluorescence quantum yields were found to be nearly zero. This suggests that the oxidized catechin molecules were seen to have slowly undergone successive chemical reactions in basic buffer solution.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.1
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• pp.69-75
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• 2009

The characteristics of disinfection and organic removal were investigated with pulse UV lamp in this study. The intensity and emission wavelength of pulse UV Lamp were compared with low pressure UV lamp. The emission spectrum range of pulse UV lamp was between 200 and 400 nm while the emission spectrum of low pressure UV lamp was only single wavelength of 254nm. 3 Log inactivation rate of B. subtilis spore by pulse UV and low pressure UV irradiation was determined as $44.71mJ/cm^2$ and $57.7mJ/cm^2$, respectively. This results implied that wide range of emission spectrum is more effective compared to single wavelength emission at 254nm. 500ng/L of initial 2-MIB concentration was investigated on the removal efficiency by UV only and $UV/H_2O_2$ process. The removal efficiency of UV only process achieved approximately 80% at $8,600mJ/cm^2$ dose. 2-MIB removal rate of $UV/H_2O_2$ (5 mg/L $H_2O_2$) process was 25 times increased compared to UV only process. DOC removal efficiency for the water treatment plant effluent was examined. The removal efficiency of DOC by UV and $UV/H_2O_2$ was no more than 20%. Removal efficiency of THMFP(Trihalomethane Formation Potential), one of the chlorination disinfection by-products, is determined on the UV irradiation and $UV/H_2O_2$ process. Maximum removal efficiency of THMFP was approximately 23%. This result indicates that more stable chemical structures of NOM(Natural Organic Matter) than low molecule compounds such as 2-MIB, hydrogen peroxide and other pollutants affect low removal efficiency for UV photolysis. Consequently, pulse UV lamp is more efficient compared to low pressure lamp in terms of disinfection due to it's broad wavelength emission of UV. Additional effect of pulse UV is to take place the reactions of both direct photolysis to remove micro organics and disinfection simultaneously. It is also expected that hydrogen peroxide enable to enhance the oxidation efficiency on the pulse UV irradiation due to formation of OH radical.

• Journal of The Korean Astronomical Society
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• v.29 no.2
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• pp.223-243
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• 1996

We have constructed a line-by-line model of the A-X system of CO in order to analyze the CO bands appearing in the UV spectra of comets. The model includes electronic, rotational, vibrational transitions, excitations by solar UV radiation, and effects of neutral and electron collisions. The major bands of the A-X system occur in the $1200 - 1800{\AA}$ range where the temporal variation of solar irradiation is significant. The solar spectrum in this spectral range shows many emission lines, which cause a significant Swings effect. We derived fluorescence efficiencies of the bands as functions of heliocentric velocity and cometocentric distance using a high resolution spectrum of the sun. We compared our model with a spectrum of comet P/Halley obtained with the IUE, and estimated that the UV Swings effects are less than 20 fluorescence efficiencies for the most bands of the A-X system. We discuss the temporal variation of solar UV irradiation and its effects on the fluorescence efficiencies. The study of the A-X system also requites knowledge of vibrational and rotational fluorescent processes in the infrared and radio regions because the majority of CO molecules in the coma is in the ground rotational states. The solar infrared spectrum near 5 microns, where the fundamental band of CO occurs, contains strong absorption lines of the fundamental band and hot bands of CO and its isotopes. We derived fluorescence efficiencies of the infrared band as functions of heliocentric velocity and cometrocentric distance. The solar absorption lines near 5 microns cause a 20 reduction of the g-factor of the fundamental band at heliocentric velocities close to 0 km/sec. We discuss the effects of neutral and electron collisions on the fluorescence efficiencies of the infrared and UV bands.