• 제목, 요약, 키워드: UV (ultraviolet) light

검색결과 349건 처리시간 0.213초

광 루미네슨스 다공질 실리콘을 이용한 새로운 자외선 센서 (A Novel Ultraviolet Sensor using Photoluminescent Porous Silicon)

  • 민남기;고주열;강철구
    • 대한전기학회논문지:전기물성ㆍ응용부문C
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    • v.50 no.9
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    • pp.444-449
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    • 2001
  • In this paper, a novel ultraviolet sensor is presented based on a photoluminescent porous silicon. Porous silicon layer was formed by chemical etching of surface of pn junction in a $HF(48%)-HNO_3(60%)-H_20$ solution. Incident ultraviolet(UV) light is converted to visible light by photoluminescent porous silicon layer, and then this visible light generates electron-hole pairs in the pn junction, which produces a photocurrent flow through the device. In order to maximize detection efficiency, the peak sensitivity wavelength of the pn junction diode was matched with the peak wavelength of Photoluminescence from porous silicon layer. The porous silicon ultraviolet sensor showed a large output current as UV intensity increases and but very low sensitivity to visible light. The detection sensitivity of porous silicon sensor was calculated as 2.91mA/mW. These results are expected to open up a possibility that the present porous silicon sensor can be used for detecting UV light in a visible background, compared to silicon UV detectors which have an undesirable response to visible light.

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

  • 서대식;황율연;이보호
    • E2M - 전기 전자와 첨단 소재
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    • v.10 no.5
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    • pp.461-466
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    • 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.

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Effects of Package Materials on Quality Change of Pine Bud Beverage Under Ultraviolet Light

  • An, Duek-Jun
    • Preventive Nutrition and Food Science
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    • v.14 no.4
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    • pp.349-353
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    • 2009
  • The effects of packaging materials on preserving the functional component of pine bud beverage stored under UV (ultraviolet) light exposure conditions were studied. The order of UV light blocking properties of the selected packages was: opaque can> opaque PET (polyethylene terepthalate) with green lamination=transparent PET with 10% PEN (polyethylene naphthalate) blending> transparent PET, and did not depend on film thickness in specified range. At 20${^{\circ}C}$, the order of preserving degree of original color and endobornyl acetate, which is quality index of pine bud beverage, was the same as above. Exposure to UV light can cause of deterioration of functional food components, but green color lamination and blending of PEN materials with transparent PET help to preserve the UV sensitive pine bud beverage components. However, the treated PET bottles have poorer preservation capabilities than the opaque cans. Transparent PET with PEN blending, in particular, will be very useful packaging material for colorful functional beverage preservation by helping to protect the ingredients while attracting consumer attention.

Involvement of lncRNA-HOTTIP in the Repair of Ultraviolet Light-Induced DNA Damage in Spermatogenic Cells

  • Liang, Meng;Hu, Ke
    • Molecules and Cells
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    • v.42 no.11
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    • pp.794-803
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    • 2019
  • Ultraviolet light (UV)-induced cellular response has been studied by numerous investigators for many years. Long noncoding RNAs (lncRNAs) are emerging as new regulators of diverse cellular process; however, little is known about the role of lncRNAs in the cellular response to UV treatment. Here, we demonstrate that levels of lncRNA-HOTTIP significantly increases after UV stimulation and regulates the UV-mediated cellular response to UV through the coordinate activation of its neighboring gene Hoxa13 in GC-1 cells (spermatogonia germ cell line). UV-induced, G2/M-phase arrest and early apoptosis can be regulated by lncRNA-HOTTIP and Hoxa13. Furthermore, lncRNA-HOTTIP can up-regulate ${\gamma}-H_2AX$ and p53 expression via Hoxa13 in UV-irradiated GC-1 cells. In addition, p53 has the ability to regulate the expression of both lncRNA-HOTTIP and Hoxa13 in vitro and in vivo. Our results provide new data regarding the role lncRNAs play in the UV response in spermatogenic cells.

Ultraviolet Light Sensor Based on an Azobenzene-polymer-capped Optical-fiber End

  • Cho, Hee-Taek;Seo, Gyeong-Seo;Lim, Ok-Rak;Shin, Woojin;Jang, Hee-Jin;Ahn, Tae-Jung
    • Current Optics and Photonics
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    • v.2 no.4
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    • pp.303-307
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    • 2018
  • We propose a simple ultraviolet (UV) sensor consisting of a conventional single-mode optical fiber capped with an azobenzene-moiety-containing polymer. The UV light changes the dimensions of the azobenzene polymer, as well as the refractive index of the material. Incident light with a wavelength of 1550 nm was reflected at the fiber/polymer and polymer/air interfaces, and interference of the reflected beams resulted in spectral interference that shifted the wavelength by 0.78 nm at a UV input power of $2.5mW/cm^2$. The UV sensor's response to wavelength is nonlinear and stable. The response speed of the sensor is limited by detection noise, which can be improved by modifying the insertion loss of the UV sensor and the signal-to-noise ratio of the detection system. The proposed compact UV sensor is easy to fabricate, is not susceptible to electromagnetic interference, and only reacts to UV light.

Measurement Technique of Ozone Density by Using UV Sensor System

  • Trung, Nguyen Huu;Van Men, Le;Van Hieu, Nguyen
    • 전기전자학회논문지
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    • v.19 no.1
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    • pp.80-86
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    • 2015
  • There are many studies and products using a test paper impregnated with chemical solution can react with ozone. The color of a test paper can indicate the concentration of ozone. The purpose of this research is to design and manufacture a system using ultraviolet light source to measure the ozone density. This new technique is based on the characteristic of decomposition from ozone into oxygen under ultraviolet light. We used two sources of ultraviolet light including UV lamp and UVLED to determine the decomposition of ozone. This system is built with the electronic components, sensors and sealed pump tube to measure the ozone density in units of $g/cm^3$,ppm,ppb. In this paper,, we present some initial results of measuring the ozone density from ozone generator after completing inspection for safety.

Dependence of Retardation Dispersion on the Ultraviolet Polarization Direction During Photopolymerization of Self-organized Smectic Reactive Mesogen Molecules

  • Jeong, Jinyoung;Choi, Yu-Jin;Jeong, Kwang-Un;Lee, Ji-Hoon
    • Current Optics and Photonics
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    • v.2 no.3
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    • pp.286-290
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    • 2018
  • We investigated the dependence of the retardation dispersion on the polarization direction of ultraviolet (UV) light during the photopolymerization of self-organized smectic reactive mesogen (RM) molecules. RM retarder film that was photopolymerized with UV light linearly polarized parallel to the layer plane showed negative dispersion (ND) of retardation for a wide range of UV polymerization temperatures. On the other hand, film that was photopolymerized with unpolarized UV light showed negative dispersion in a narrow range of UV polymerization temperatures. With a certain UV polymerization temperature, the dispersion of retardation was converted from positive to negative, depending on the UV polarization.

Measurement of UV radiation of LED lighting

  • Ku, Seong-Mo;Im, Jong-Min;Yi, Chin-Woo
    • 조명전기설비학회논문지
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    • v.25 no.3
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    • pp.7-14
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    • 2011
  • Many countries and researchers in the lighting field have focused on the LED light source as a solution to energy savings and environmental pollution. The LED light source consumes less power, has a long life and is highly economical. It is vibration and shock-resistant, and environment friendly as well. But LED lighting has some problems. In particular, the photobiological safety of LED light sources is emerging as an issue. Ultraviolet radiation from the LED light source emitted directly to the human body over a long period of time is harmful. In this paper, UV radiation from white LED was measured. Finally, the LED light source emits UV radiation, but it is relatively small when compared to others.

안경렌즈의 자외선 차단 평가 (Evaluation of Ultraviolet Blocking of Ophthalmic Lenses)

  • 유동식;유종숙
    • 한국안광학회지
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    • v.13 no.3
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    • pp.7-12
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    • 2008
  • 목적: 투명과 착색 안경렌즈의 자외선 차단 특성을 평가하고자 하였다. 방법: 안경렌즈의 투과 스펙트럼은 ANSI Z80.1에 제시된 방법으로 측정하였고, UV(200~380 nm; UVA, UVB, UVC) 및 청색광 영역(380~400 nm)에 대하여 각 렌즈의 투과율을 계산하였다. 결과: 중굴절률, 고굴절률의 투명 플라스틱 렌즈 및 착색 플라스틱 렌즈는 UV에서 우수한 자외선 차단 특성을 보였으나, 자외선 차단제를 처리하지 않은 크라운 유리나 CR39는 그렇지 않았다. 고굴절률 렌즈와 눈부심 방지 야간용 렌즈를 제외한 모든 렌즈는 청색광을 효과적으로 차단하지 않았다. 결론: 크라운 유리와 CR39 렌즈는 UV로부터 눈을 보호하기 위해서 자외선 차단제가 필요하다. 또한 고굴절률 렌즈와 눈부심 방지 야간용 렌즈를 제외한 모든 렌즈는 청색광으로부터 눈을 보호하기 위해서 청색광 차단제가 필요하다.

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피부 미용에 있어서 자외선 차단제의 개발 및 유효 안전성 (Development and Efficiency-Stabilization of UV Blocking Agents Used to Skincare)

  • 김상춘;남기대;이향우
    • 한국응용과학기술학회지
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    • v.12 no.2
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    • pp.157-163
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    • 1995
  • The ultraviolet blocking agents used to skincare are largely classified ultraviolet scattering agent and ultraviolet absorbent agents. There are UVC, UVB, and UBA in ultraviolet ray(UV) showing shorter wavelength than visible light. Both visible light and UVA give rise to 1st dark-skinned phenomena. On exposure of the skin to UV, phenomena of skin variation are termed sunburn or suntan. There are chronic and acute adverse reactions in skin response to UV. The latter is caused by UVB, which has mainly effects on the skin. But lately due to destruction of ozone layer, UVA has more serious irritation on the skin than UVB. In this paper spectrometric properties of UV absorbent agents such as PABA, octyl-PABA, Urocanic acid, and 2-hydroxy-4-methoxy benzophenone in vitro have been investigate. As results, it was found that the three fomer were more suitable than the last. UV scattering measurements on the sample used inorganic pigments showed that pigments containing titanium dioxide had a better scattering effects than the inorganic pigments such as $Fe_2O_3$, $Al_2O_3$, etc.