• Journal of Photoscience
• /
• 제9권2호
• /
• pp.454-456
• /
• 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
• /
• 제15권4호
• /
• pp.26-31
• /
• 1987

맹종죽, 왕대, 솜대 Dioxane Lignin의 UV, IR spectrum의 특징(特徵)을 조사(調査)하여 본 바, 그 결과(給果)를 요약하면 다음과 같다. 1. UV spectrum에 있어서는 일반적(一般的)인 Lignin spectrum과 같이 Maximum peak, Shallow minium peak, Minimum peak의 3개소(個所)를 보였는데 Max. peak는 210nm 부근(附近), Shallow peak는 260-270nm에, Minimum peak는 280nm부근(附近)에 있었다. 2. 280nm부근(附近)의 Minimum peak는 Lignin이 갖는 특징적(特徵的)인 peak로서 일반(一般) 침엽수재(針棄樹材) Lignin이나 활엽수(闊葉樹) Lignin과는 달리 282-285nm에서 흡광도(吸光度)가 꼭 같아 아주 완만한 peak 를 보여 주었다. 3. IR spectrum에 있어서는 방향핵(芳香核) 흡수대(吸收帶)는 $1550cm^{-1}$ 부근(附近)에 있고 1040-$1130cm^{-1}$부근(附近)과 1230-$1275cm^{-1}$에서의 Spectrum 형태(形態)는 활엽수(闊葉樹)에 가깝고 침엽수재(針葉樹材) Lignin의 spectrum과는 상반되는 모습을 보여 주었다.

• 한국음향학회:학술대회논문집
• /
• 한국음향학회 1992년도 학술논문발표회 논문집 제11권 1호
• /
• pp.43-48
• /
• 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.

• 대한환경공학회지
• /
• 제34권11호
• /
• pp.743-750
• /
• 2012

$ClO_{2(aq)}$ 분석 방법 중 하나인 UV 흡수법은 여러 염소종이 함유된 용액에서는 흡수 파장 겹침 현상으로 분석에 어려움이 있다. 이러한 문제를 극복하고자 UV 파장 분해법을 이용한 다양한 염소종이 함유된 용액의 $ClO_{2(aq)}$ 농도 정량법을 제안하였다. UV 파장 분해법을 이용한 $ClO_{2(aq)}$ 농도 값은 적정법을 이용한 $ClO_{2(aq)}$ 농도 값과 10%내에서 일치하였다. 따라서 다양한 염소 종들이 포함된 시료에서도 제안된 UV 파장 분해법을 적용한다면 $ClO_{2(aq)}$의 선택적 분석이 가능하다는 것을 알 수 있었다.

• 한국항행학회논문지
• /
• 제11권1호
• /
• pp.87-92
• /
• 2007

기존의 CELP 계열 보코더에서, 무성음에 대한 별도의 처리 없이 유성음과 동일하게 처리함으로써 합성음에서 음질의 저하 및 계산량과 전송률 측면에서 손실을 가져왔다. 본 논문에서는 에러율과 전처리 계산량을 최소로 할 수 있는 V/UV 분류기를 사용하여 CELP 보코더에서 전송률을 감소시키는 방법을 제안한다. 새로운 V/UV 분류기는 CELP 보코더에서 사용되는 LSP 파라미터의 주파수영역 분포도와 간격정보를 이용하여 V/UV를 결정하게 된다. 제안한 방법을 G.723.1 5.3kbps ACELP에 적용하여 성능 평가를 실시하였다. 실험결과, 음질의 저하 없이 약 6%의 전송률을 감소할 수 있었다.

• 한국식품과학회지
• /
• 제37권3호
• /
• pp.360-363
• /
• 2005

가시오가피에서 Polyacetylene 성분 중 falcarinol을 탐색하기 위해 TLC, HPLC/PDA, GC, GC/MS를 이용하여 falcarinol 표준품과 소분획물 사이의 비교 분석을 통하여 가시오가피에서 falcarinol을 동정하였다. 가시오가피 추출물을 silica gel column상에서 용매의 극성차이에 의해 6개의 분획물을 얻었고, 6개의 분획물과 falcarinol 표준품과의 TLC 상에서 전개시킨 결과 fraction 6 분획물에서 falcarinol과 동일 band의 물질을 분리하였다. Fraction 6의 분획물과 falcarinol 표준품을 HPLC/PDA로 분석한 결과 falcarinol 표준품의 peak와 동일 retention time의 peak를 fraction 6에서 분리하여 200-340nm 상에서 UV spectrum을 관찰한 결과 동일한 UV spectrum pattern을 보이는 것을 확인하였다. 이는 전형적인 polyacetylene 화합물의 UV spectrum pattern이었으며, 기존에 보고된 falcarinol의 UV spectrum과도 동일하였다. GC로 TMS 유도체화 전,후의 retention time을 확인한 결과 표준품과 fraction 6에서 동일한 결과를 보였다. TMS 유도체화 후에는 7.5분에서 8.5분으로 약 1분 정도 retention time이 증가하였고, detection 감도 또한 증가하였다. Falcarinol 표준품과 fiaction 6 분획물을 TMS 유도체화 후에 GC/MS로 mass fragment ion을 분석한 결과 표준품과 동일한 경향을 보였고 이는 기존의 보고와도 일치하였다(16). 본 실험결과들로 미루어 가시오가피에도 polyacetylene 성분인 falcarinol 존재하는 것으로 확인되었다.

• 한국식품영양학회지
• /
• 제7권4호
• /
• pp.332-337
• /
• 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
• /
• 제32권9호
• /
• pp.3443-3447
• /
• 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.

• 상하수도학회지
• /
• 제23권1호
• /
• pp.69-75
• /
• 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.

• 천문학회지
• /
• 제29권2호
• /
• pp.223-243
• /
• 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.