• Title/Summary/Keyword: UV light

Search Result 723, Processing Time 0.161 seconds

Relationship between the pretilt angle generation and the polarization component with oblique polarized UV light irradiation on polyimide surface. (폴링미드표면에 편광된 UV광을 경사조사시의 프리틸트각의 발생과 편광성분의 상호관계)

  • 서대식;박두석
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.12 no.1
    • /
    • pp.75-80
    • /
    • 1999
  • In this study, we have investigated the relationship between the generation of pretilt angle and the polarization component in cells with UV light irradiation on polyimide (PI) surface. It was found that the generated pretilt angle is about $1.4^{\circ}$ with S-polarized UV light irradiation of $75^{\circ}$ on PI surface; it may be attributed to the asymmetry triangular of polymer surface with oblique S-polarized UV light irradiation on PI surface. Also, we measured that the generated pretilt angle is about $2.0^{\circ}$ with oblique P polarized UV light irradiation of $75^{\circ}$ on PI surface. Consequently, we suggest that the generated pretilt angle of the NLC is attributed to the interaction between the LC molecules and the polymer surface with oblique polarized UV light irradiation on PI surface.

  • PDF

Physiological characterization of mechanism on UV light-induced photorelaxation in isolated rat aorta (쥐의 적출 대동맥에 자외선 조사로 유발된 photorelaxation 기작의 생리학적 특성)

  • Lee Han-Ki;Hong Yong-geun;Kim Kyung
    • The Journal of Korean Physical Therapy
    • /
    • v.15 no.2
    • /
    • pp.146-156
    • /
    • 2003
  • Isolated rat thoracic aorta which is pharmacologically precontracted by phenylephrine induces photorelaxation when exposed to long wave length UV-light. The aim of the present study was to characterize the mechanism of UV-light induced by photorelaxation in the rat aorta. 1. UV light relaxed both endothelium-intact and -denuded rat aortic rings contracted by phenylephrine. The magnitude of relaxation on UV light was dependent on the exposure time and slightly greatly in endothelium-denuded rings than in endothelium-intact preparations. 2. L-NAME (10 nM - 100 $\mu$M) but not D-NAME completely inhibited the photorelaxation in a concentration dependent manner. 3. The UV-induced relaxation was inhibited by methylene blue (1 - 100 uM), and verapamil (100 nM), and removal of extracellular $Ca^{2+}$. In contrast, UV-light induced photorelaxation was potentiated by $N^{w}$-nitro-L-arginine (L-NNA) treatment. These results suggest that UV light-induced photorelaxation may be due to nitric oxide from exogenously administered L-arginine as well as endogenous nitric oxide donors such as amino acid and arginine derivatives

  • PDF

Changes in Bioactive Compounds Contents of 'Maehyang' and 'Seolhyang' Strawberry Fruits by UV Light Illumination

  • Kim, Sung-Kyeom;Bae, Ro-Na;Chun, Chang-Hoo
    • Horticultural Science & Technology
    • /
    • v.29 no.3
    • /
    • pp.172-180
    • /
    • 2011
  • The net photosynthetic rate of 'Seolhyang' strawberry plants was measured daily for 7 days after treatment at three UV illumination dosages (0, 9.8, and 29.5 $kJ{\cdot}m^{-2}$). The net photosynthetic rates of the strawberry plants with 9.8 and 29.5 $kJ{\cdot}m^{-2}$ UV light illumination decreased by 20.2 and 61.4%, respectively, at 7 days after UV light treatments. UV treatments with two illumination dosages (7.9 and 15.7 $kJ{\cdot}m^{-2}$) altered the phenolic compounds contents during the cultivation period when compared to those in the control fruits. The anthocyanin content with 7.9 $kJ{\cdot}m^{-2}$ UV light illumination of 'Seolhyang' increased by 18.7% compared with those in control fruits at the 11 DAT. However, the anthocyanin content of 'Maehyang' was not significantly different among treatments during experiment period. The highest level of ellagic acid was found with 7.9 $kJ{\cdot}m^{-2}$ UV light illumination in both cultivars at the 11 DAT. Our results showed that strawberries illuminated with UV light during cultivation period had higher bioactive compounds contents than control fruits. These results suggest that UV light treatments may be a useful non-chemical way of promoting strawberry fruits quality.

Relationship between the pretilt angle generation and the polarization component with linearily polarized UV light irradiation on polymer surface. (직선편광된 UV광을 폴리이미드막에 조사한 경우의 프리틸트각의 발생과 편광성분의 상호관계)

  • Seo, Dae-Shik;Park, Doo-Seok;Han, Jeong-Min
    • Proceedings of the KIEE Conference
    • /
    • 1998.07d
    • /
    • pp.1391-1394
    • /
    • 1998
  • In this paper, we investigated the generation of pretilt for nematic liquid crystal (NLC) in a cell with linearly polarized ultraviolet (UV) light irradiation on polyimide (PI) surface. The pretilt angle of the NLC increases with increasing the incident angle in the cells with S-wave polarized UV light irradiation on PI surface. It is considered that the pretilt angle of the NLC increased due to decreasing the UV light intencity. We suggest that the pretilt angle of the NLC is attributed to asymmetry triangular of the polymer surface with S-wave polarized UV light irradiation on PI surface. Also, we consider that the asymmetry triangular of the Polymer not formed with P-wave polarized UV light irradiation on PI surface. Therefore, the pretilt angle of the NLC is attributed to asymmetry triangular of the polymer surface with UV light irradiation on PI surface.

  • PDF

Improvement of Sensitivity in Porous Silicon Alcohol Gas Sensors by UV Light (자외선조사에 의한 다공질 실리콘 알코올 센서의 감도 개선)

  • Kim, Seong-Jin;Choe, Bok-Gil
    • The Transactions of the Korean Institute of Electrical Engineers C
    • /
    • v.48 no.9
    • /
    • pp.676-680
    • /
    • 1999
  • To do breath alcohol measurement, a sensor is necessary that it can detect low alcohol gas concentration of 0.01% at least. In this work, a capacitance-type alcohol gas sensor using porous silicon layer is developed to measure low alcohol gas concentration. The sensor using porous silicon layer has some sensitivity at room temperature by very large effective surface area, but there is still much room for improvement. In this experiment, we measured the capacitance of the sensor under 254 nm UV light on the porous silicon layer, in which alcohol solution was kept in a flask at 25, 35, and $45^{\circ}C$ by a heater. As the result, the improvement of sensitivity by illuminating UV light was observed. The increasing rate of the capacitance was shown to be double more than those measured under UV-off state. It is supposed that UV light activates response of the oriental and interfacial polarizations which have slow relaxation time for AC field.

  • PDF

Pretilt Angle Generation and EO Performance in MLC with Polarized UV Light Irradiation Polyimide surface (폴리이미드막 표면에 직선 편광된 UV광 조사에 의한 프리틸트각 발생과 전기광학특성)

  • 서대식;이정호;이창훈
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.11 no.10
    • /
    • pp.878-884
    • /
    • 1998
  • We have investigated that the monodomain alignment of nematic liquid crystal (NLC) is obtained with polarized ultraviolet(PUV) light irradiation on polyimide (PI) surface. The LC alignment capability increases with increasing the UV light irradiation time. The polarized UV light irradiation on oblique angle of 60。 irradiated on PI surface rotated by 90。 at 10 min. after being normally irradiated on PI surface at 30 min., the generated pretilt angle of NLC is about 2.5。. The pretilt angle of NLC is attributed to the interaction between the LC molecules and the asymmetric triangular structure of polymer surface due to photo-depolymerization of polymer with the oblique UV light on PI surface. The voltage -transmittance and response time characteristics of photo-aligned twisted nematic (TN)-LCD with UV light irradiation time 60 min. were almost same in comparison with the rubbing-treated TN-LCD.

  • PDF

Effects of UV light irradiation condition and imidization temperature for the generation of pretilt angle on polyimide surfaces (폴리이미드 표면에서의 프리틸트각 발생에 대한 UV조사 조건과 이미드화온도의 영향)

  • Yu, Mun-Sang;Seo, Dae-Shik;Hwang, Jeoung-Yeon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 1998.11a
    • /
    • pp.61-64
    • /
    • 1998
  • We have investigated the effects of ultraviolet (UV) light irradiation condition and imidization temperature for the generation of pretilt angle in nematic liquid crystal (NLC) on the two kinds of the polyimide (PI) surfaces. High pretilt angle of NLC is generated with oblique p-polarized UV light irradiation of 30$^{\circ}$ on PI surface for 20 min. Also, the high pretilt angle of NLC is generated with oblique p-polarized UV light irradiation of 10-30$^{\circ}$ on PI surface at 20min. The pretilt angle of NLC decreases with increasing the imidization temperature on all rubbed PI surfaces ; the pretilt angle of NLC with oblique p-polarized UV light irradiation of 30$^{\circ}$on PI surface decreases with increasing the imidization temperature. The high pretilt angle of NLC is observed due to high photo-depolymerization reaction by low surface energy at low imidization temperature. We suggest that the pretilt angle of NLC is strongly attributed to the photo-depolymerization reaction with the UV light irradiation condition and imidization temperature.

  • PDF

Involvement of Nitric Oxide and Prostanoid on Photorelaxation in Pig Renal Artery (UV-light 에 의한 혈관 이완작용에 있어서 nitric oxide와 prostanoid의 관련성)

  • Kim, Joo-Heon;Shim, Cheol-Soo;Jeon, Seok-Cheol
    • Korean Journal of Veterinary Research
    • /
    • v.42 no.3
    • /
    • pp.321-326
    • /
    • 2002
  • The effect of nitric oxide synthase(NOS) inhibita, $N^G$-nitro-L-arginine-methyl ester(L-NAME) and prostanoid synthesis inhibiter, indomethacin on the photorelaxation, when was exposed to the long-wave length UV-light, was examined on the precontraction by the phenylephrine in the isolated pig renal artery. 1. UV-light relaxed both with-endothelium and without-endothelium in the pig renal arterial ring contracted by the phenylephrine. The magnitude of photorelaxation was dependent on the exposure time for UV-light. 2. UV-Iight induced relaxation was inhibited by L-NAME and indomethacin on the precontraction by the phenylephrine in the isolated pig renal artery. 3. UV-Iight induced relaxation was inhibited by methylene blue on the precontraction by the phenylephrine in the isolated pig renal artery. These results suggest that UV-light induced photorelaxation may be due to cGMP involved both nitric oxide and prostanoid on the precontraction by the phenylephrine in the isolated pig renal artery.

A Study on Alignment of Nematic Liquid Crystal by Using Slanted Non-polarized Ultraviolet Light Irradiation on Polyimide Film (폴리이미드막표면위에 경사진 자외선 조사를 이용한 네마틱 액정의 배향에 관한 연구)

  • 서대식;황율연;이보호
    • Electrical & Electronic Materials
    • /
    • v.10 no.5
    • /
    • pp.461-466
    • /
    • 1997
  • In this paper, we developed the new non-rubbing liquid crystal (LC) alignment techniques in the cell with slanted non-polarized ultraviolet (UV) light irradiation on polyimide (PI) film. It is shown that the uniform alignment for nematic (N) LC is obtained by using slanted non-polarized UV light irradiation on PI surface. We successfully obtained that the pretilt angle of NLC is generated about 3.3 degree in the cell with slanted non-polarized UV light irradiation with 70 degree on PI surface, for the first time. It is considered that the pretilt angle generation in NLC is attributed to interaction between the LC molecular and the PI, which is broken the polymer by slanted non-polarized UV irradiation. Therefore, we concluded that the uniform LC alignment is attributed to anisotropic dispersion force due to photo depolymerization with slanted non-polarized UV light irradiation on PI surface.

  • PDF

A Study on the matter of Disinfection in UV/TiO2 Water Treatment process (UV/TiO2 수처리 공정에서의 살균에 관한 연구)

  • Lee, Gyu-Hwan;Lee, Sang-Jin;Lee, Yong-Jae;Rhee, Dong-Seok
    • Journal of Industrial Technology
    • /
    • v.27 no.A
    • /
    • pp.15-18
    • /
    • 2007
  • This study investigated disinfection effect by general water purifier and water purifier with UV light disinfection. The results are as follows : (i) The general bacteria existed plentifully in a storage tank before treatment (ii) Water treated in water purifier did not meet the water treatment regulation standard since the presence of bacteria, whereas with UV light application the regulation standard is totally satisfied. (iii) Photocatalytic disinfection process with UV light in the presence of $TiO_2$ more effectively killed general bacteria than UV light only.

  • PDF