• Title/Summary/Keyword: UV light

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Standardization of a Mass-Production Technique for Pycnidiospores of Dydymella bryoniae, Gummy Stem Blight Fungus of Cucurbits (박과작물 덩굴마름병 Didymella bryoniae의 병포자 대량 생산 방법의 표준화)

  • 권미경;홍정래;선해정;성기영;조백호;김기청
    • Korean Journal Plant Pathology
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    • v.13 no.2
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    • pp.105-112
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    • 1997
  • Didymella bryoniae, gummy stem blight fungus of cucurbits, has been known not to produce its pycnidium in vitro without irradiation. Various methods for producing pycnidiospores of the fungus as an inoculum have been used. However, those methods have not been verified in terms of efficiency of the productivity, activity and synchronous maturation of the inoculum. Therefore, a pycnidiospore production method in vitro that is highly reliable and reproducible has to be developed to obtain a large amount of inoculum for screening disease resistant varieties or effective fungicides. Here we standardized a mass-production technique for pycnidiospores of D. bryoniae in vitro by comprehensively finding the optimal conditions such as kinds and thickness of cultural medium, growing temperature, and quality and duration of irradiation as well as examining the activity and pathogenicity of the pycnidiospores reproduced. In brief, mycelial colony on the PDA plate was cultured at 26$^{\circ}C$ for 2 days under the darkness, and then the plate was irradiated under the UV light (12 hr/a day) for 2~3 days at the same temperature(26$^{\circ}C$). Two days after UV irradiation, a great number of pycnidia was simultaneously formed. This plate was subjected to darkness again for 4~5 days to mature pycnidiospores. We could obtain a large amount of inoculum that is synchronously matured in a short period of time through the above procedures.

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The Influence of Surface Modification of Gold Nanoparticles Supported on TiO2 in the Catalytic Activity of CO Oxidation

  • Park, Da-Hee;Reddy, A.S.;Eah, Sang-Kee;Park, Jeong-Young
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.08a
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    • pp.213-213
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    • 2011
  • Gold catalysts supported on TiO2 have shown a unique catalytic behavior on CO oxidation, depending on surface effects. Particle size has an influence on the surface activity. To make monodisperse Au nanoparticles, organic capping ligands, such as alkylthiols, were used by a "greener" synthesis method [1,2] and Au nanoparticles were deposited on TiO2. However, organic capping ligands must be removed for high catalytic activities by the Au nanoparticles without changing the Au size [3]. We used UV ozone treatment to decompose thiol ligands. The samples have been characterized by X-ray photoelectron spectroscopy to examine the surface modification by UV ozone treatment. We show the size distribution of the gold nanoparticles by light scattering analysis and transmission electron microscopy. Au/TiO2 have been prepared using the wetness impregnation method. The catalytic performance of CO oxidation over Au supported on TiO2 under oxidizing reaction conditions (40 Torr CO and 100 Torr O2) were tested. The results show that the catalytic activity depends on particle size and the time of UV ozone exposure, which suggests the role of sulfur bonding in determining the catalytic activity of Au/TiO2 catalysts.

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Advanced surface processing of NLO borate crystals for UV generation

  • Mori, Yusuke;Kamimur, Tomosumi;Yoshimura, Masashi;Sasaki, Takatomo
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.9 no.5
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    • pp.459-462
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    • 1999
  • Recent advances in NLO Borate Crystals for UV Generation are reviewed with the particular emphasis on the technique to improve the life time of UV optics. The laser-damage resistance of CLBO and fused silica surfaces was successfully improved after removing polishing compound by ion beam etching. The polishing compound embedded in the CLBO and fused silica surfaces were to a depth of less than 100nm. We were able to remove polishing compound without degrading the surface condition when the applied ion beam voltage was less than 200 V. The laser-induced surface damage threshold of CLBO was improved up to 15J/$\textrm{cm}^2$(wavelength: 355 nm, pulse width: 0.85 ns)as compared with that of the as-polished surface (11 J/$\textrm{cm}^2$). The laser-induced surface damage of fused silica also increased from 7.5J/$\textrm{cm}^2$ to 15J/$\textrm{cm}^2$. For the irradiation of a 266 nm high-intensity and high-repetition laser light, the surface lifetime of CLBO and fused silica could be more doubled compared with that of the as-polished surface.

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A Study of frequency tunable Ti:sapphire laser for UV lidar (UV 라이다용 주파수 가변 Ti:sapphire 레이저에 관한 연구)

  • Yi, Yong-Woo
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2002.11a
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    • pp.656-661
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    • 2002
  • Multipass Ti:sapphire amplifier for the light source of lidar was developed in an angular-multiplexing, and the characteristics of output energy and spectrum was investigated. In the two-stage multipass amplifier, we obtained the maximum output energy of 42 mJ, the amplification gain of 21 dB and the output efficiency of 26% on the wavelength of 790 nm. In the tuning range of 715~930nm the spectral linewidth is 0.05 $cm^{-1}$ /. The conversion efficiencies of 35% for SHG at 780 m and 13% for THG at 390 nm are obtained respectively. The continuous tunabilities of 240~306 m UV region and 360~460 nm in deep-blue region could be achieved.

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Effects of transition metal-doping on the properties of ZnO nanoparticles and the photocatalytic degradation of methylene blue (전이금속 도핑이 ZnO 나노분말의 특성 및 메틸렌블루 광촉매 분해 특성에 미치는 영향)

  • Chang, Han Kwon;Oh, Kyung Jun;Jang, Hee Dong;Cho, Kuk;Kim, Dong-Jin;Choi, Jin Hoon
    • Particle and aerosol research
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    • v.6 no.1
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    • pp.29-35
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    • 2010
  • Transition metals such as V, Fe, and Ni were used to synthesize doped zinc oxide nanoparticles from mixed liquid precursors by using the flame spray pyrolysis (FSP). The effects of dopants on the powder properties such as morphology, specific surface area, crystal structure, and light adsorption were analyzed by TEM, BET, XRD, and UV-Vis diffuse reflection spectrum (DRS), respectively. The results showed that hexagonal wurtzite structured ZnO:M (M = V, Fe, Ni) nanoparticles were successfully synthesized by the FSP. The transition metal-doping resulted in the decrease in its particle size and crystallite size. The UV-vis absorption spectra of ZnO:M nanoparticles were also red-shifted. ZnO:V showed the highest MB degradation of 99.4% under the UV irradiation after 3 hrs.

Adsorption Kinetics for Polymeric Additives in Papermaking Aqueous Fibrous Media by UV Spectroscopic Analysis

  • Yoon, Sung-Hoon;Chai, Xin-Sheng
    • Bulletin of the Korean Chemical Society
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    • v.27 no.11
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    • pp.1819-1824
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    • 2006
  • The general objective of the present study was to investigate the potential application of the UV spectroscopic method for determination of the polymeric additives present in papermaking fibrous stock solutions. The study also intended to establish the surface-chemical retention model associated with the adsorption kinetics of additives on fiber surfaces. Polyamide epichlorohydrin (PAE) wet strength resin and imidazolinium quaternary (IZQ) softening agents were selected to evaluate the analytical method. Concentrations of PAE and IZQ in solution were proportional to the UV absorption at 314 and 400 nm, respectively. The time-dependent behavior of polymeric additives obeyed a mono-molecular layer adsorption as characterized in Langmuir-type expression. The kinetic modeling for polymeric adsorption on fiber surfaces was based on a concept that polymeric adsorption on fiber surfaces has two distinguishable stages including initial dynamic adsorption phase and the final near-equilibrium state. The simulation model predicted not only the real-time additive adsorption behavior for polymeric additives at high accuracy once the kinetic parameters were determined, but showed a good agreement with the experimental data. The spectroscopic method examined on the PAE and IZQ adsorption study could potentially be considered as an effective tool for the wet-end retention control as applied to the paper industry.

Dyeability and Functionality of Wool Fabrics Dyed with Chamaecyparis obtusa Leaf Extract (편백나무 잎 추출물로 염색한 모직물의 염색성 및 기능성)

  • Ko, Eunsook;Lee, Hyesun;Han, Chunghun
    • Journal of the Korean Society of Clothing and Textiles
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    • v.43 no.2
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    • pp.288-296
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    • 2019
  • This study examined the proper dyeing conditions, color fastness and functionality for wool fabrics dyed with Chamaecyparis obtusa leaf extract. FT-IR and UV-Vis spectrum analysis showed that tannin and flavonoids were contained in the extracted colorant. The dyeing of wool fabrics using Chamaecyparis obtusa leaf was good without pretreatment or mordant treatment. Optimal dyeing conditions for wool fabrics were a colorant concentration of 70%(v/v), dyeing temperature of $100^{\circ}C$, dyeing time of 100 minutes and dyebath pH of 5.8. Color fastness of dyed wool fabrics to washing, rubbing, perspiration was good, whereas light was grade 3. The UV protection rate and deodorization rate of wool fabrics dyed with Chamaecyparis obtusa leaf improved. Reduction rate of Staphylococcus aureus/Klebsiella pneumoniae were excellent at 99.9%. Therefore, it was confirmed that Chamaecyparis obtusa leaf can be used as environ-mentally friendly natural dye.

The Effect of Light on the Stability of IV admixture with 5-Fluorouracil (정맥주사제 혼주시 5-fluorouracil의 차광유무에 따른 안정성에 관한 연구)

  • Lee, Eun Kyung;Suh, Okkyung;Lee, Suk Hyang;Shin, Hyun Taek
    • Korean Journal of Clinical Pharmacy
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    • v.7 no.1
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    • pp.45-49
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    • 1997
  • The effect of the light on the stability of 5-fluorouracil admixture was investigated. Four sets of 5-fluorouracil admixture were prepared using 50 mg/ml injection in $5\%$ dextrose solution in PVC bags and glass bottles: (1) 5-fluorouracil 1 mg/ml concentration in glass bottles, (2) 5-fluorouracil 1 mg/ml in PVC bags, (3) 5-fluorouracil 10 mg/ml in glass bottles, and (4) 5-fluorouracil 10 mg/ml in PVC bags. In each set, one group was protected from the light (control group) and the other group was exposed to the fluorescent light (study group). All admixtures were stored at room temperature for 72 hours. Also, 5-fluorouracil injections (50 mg/ml) were prepared in plastic syringes. Half of the samples of 50 mg/ml concentration were protected from the light (control group) and the other half were exposed to the fluorescent light (study group). These were stored at room temperature for 48 hours. After visual inspection, the pHs of each admixture were determined. The 5-fluorouracil concentrations were measured by high-performance liquid chromatography with UV detection, with 5-bromouracil as an internal standard. Over the study period, no visual changes were observed. The pHs of 5-fluorouracil admixtures were in the range of $8.2\~8.5$. The peak area ratios (5-FU/5-BrU) of 5-fluorouracil admixtures protected from the light were compared with those of the admixtures exposed to the light. There was no statistically significant difference between two groups during the study period (p>0.05). In conclusion, 5-fluorouracil admixtures in $5\%$ dextrose solution exposed to the light were stable for 72 hours.

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A Study on the Contaminants Precision Cleaning of Etched Silicon Wafer by Ozone/UV (오존/자외선에 의한 실리콘 웨이퍼의 정밀세정에 관한 연구)

  • Park, H.M.;Lee, C.H.;Chun, B.J.;Yoon, B.H.;Lim, C.H.;Song, H.J.;Kim, Y.H.;Lee, K.S.
    • Proceedings of the KIEE Conference
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    • 2004.07c
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    • pp.1820-1822
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    • 2004
  • In this study, major research fields are classified as ozone generation system for dry cleaning wafer of etched silicon wafer, dry cleaning process of etched silicon wafer which includes SEM analysis and ESCA analysis. The following results are deduced from each experiment and analysis. The magnitudes of carbon and silicon were similar to the survey spectrum of silicon wafer which does not cleaning, but magnitude of oxygen was much bigger Because UV light activates oxygen molecules in the oxide film on the silicon wafer.

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Studies on the Natural dyes( I ) -extraction and UV, VIS spectrum of coloring matter of gromwell- (천연염료에 관한 연구 ( I ) -자근색소의 추출 및 자외가시분광특성-)

  • Cho Kyung Rae
    • Journal of the Korean Society of Clothing and Textiles
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    • v.11 no.3 s.25
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    • pp.25-32
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    • 1987
  • The purpose of this study is to investigate optical behaviour of coloring matter of gromwell -extracted by water, acetic acid/methanol, and the other solvents. The results were as following: UV, VIS spectra of the solution of coloring matter of gromwell extracted by water at below $80^{\circ}C$ did not reveal in the range of the visible light wavelength and coloring matter of gromwell decomposed to blue particle at $95^{\circ}C$. The solution extracted by acetic acid/methanol was tinged with reddish purple and its spectra shifted to the longer wavelength according to increase of the solvent temperature. The color of the solution extracted by water became extinct as time went by, but that extracted by acetic acid/methanol kept up original color. In case of dried gromwell, extraction by acetic acid/methanol was easier than by water, and variation of spectra did not appear but showed hypochromic shift.

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