• Title, Summary, Keyword: Visible light

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A Study on the Reduction of VOCs Generated from Vehicle Interior Parts and Materials Using Visible-light Responsive Photocatalyst (가시광촉매를 이용한 자동차 내장재로부터 발생하는 VOCs의 저감연구)

  • Choi, Sei-Young;Yang, Seung-Gi
    • Elastomers and Composites
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    • v.48 no.3
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    • pp.209-215
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    • 2013
  • On this study, visible-light responsive photocatalyst prepared by sol-gel method was evaluated the effect of the reduction of volatile organic compounds (VOCs) occurred in vehicle interior and its property was examined. According to UV/visible result, visible-light responsive photocatalyst was found that the UV-visible peak is red shift at 420nm, is sensitive in the visible light region. With vehicle interior parts and materials coated visible-light responsive photocatalyst, VOCs was measured by GC/MS. Measuring the VOCs generated from vehicle interior parts and materials, the reduction of VOCs was confirmed.

Photocatalyst Effect of Polyester Fabrics Treated with Visible-light Responsive Photocatalyst

  • Choi, Sei Young
    • Elastomers and Composites
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    • v.51 no.1
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    • pp.31-37
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    • 2016
  • In this study, we studied the photocatalytic functionality such as deodorant, antibacterial, antistatic of polyester fabrics treated with visible-light responsive photocatalyst. According to UV/visible spectrometry result, the UV-visible peak of visible-light responsive photocatalyst was found to be red shift at 420 nm sensitive in the visible light region. Also, the deodorizing and antimicrobial performance were shown to be retained more than 99% both before washing and even after 25 times washing. According to washing durability of polyester fabrics treated with visible-light responsive photocatalyst, the reduction effects for gas such as ammonia, trimethylamine, formaldehyde and toluene after 25 times washing appeared to be retained as much as before washing. At both before washing and after 25 times washing, antistatic property showed frictional voltage of approximately 250V.

The Effects of Visible Light on Iron Release from Ferritin Related to Lipid Peroxidation in the Retina

  • Ohishi, Kentaro;Hiramitsu, Tadahisa;Matsugo, Seiichi
    • Journal of Photoscience
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    • v.9 no.2
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    • pp.427-429
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    • 2002
  • We studied iron release from ferritin by irradiating the visible light, and then followed ferritin-mediated lipid peroxidation in the rod outer segment (ROS) fraction of the porcine retina. In the presence of several phosphorus compounds such as ADP and ATP, iron release from ferritin at pH 7.0 could be induced by irradiation of the visible light to the reaction mixtures. Furthermore, iron release from ferritin in the presence of ADP depended on the incubation time and the visible light irradiation. Moreover, we investigated lipid peroxidation level in the ROS fraction by two independent assay systems including the thiobarbituric acid (TBA) and ferrous oxidation/xylenol orange (FOX) methods. The visible light induced ferritin-mediated lipid peroxidation in the ROS fraction in time- and irradiance-dependent manners. In the dark condition, iron release and lipid peroxidation were not observed. Iron release from ferritin by irradiating the visible light may play an important role in the etiology of phototoxic injuries in vivo.

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Modeling Green-light Fiber Amplifiers for Visible-light Communication Systems

  • Khushik, Muhammad Hanif Ahmed Khan;Jiang, Chun
    • Current Optics and Photonics
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    • v.3 no.2
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    • pp.105-110
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    • 2019
  • The visible-light communication (VLC) system is a promising candidate to fulfill the present and future demands for a high-speed, cost-effective, and larger-bandwidth communication system. VLC modulates the visible-light signals from solid-state LEDs to transmit data between transmitter and receiver, but the broadcasting and the line-of-sight propagation nature of visible-light signals make VLC a communication system with a limited operating range. We present a novel architecture to increase the operating range of VLC. In our proposed architecture, we guide the visible-light signals through the fiber and amplify the dissipated signals using visible-light fiber amplifiers (VLFAs), which are the most important and the novel devices needed for the proposed architecture of the VLC. Therefore, we design, analyze, and apply a VLFA to VLC, to overcome the inherent drawbacks of VLC. Numerical results show that under given constant conditions, the VLFA can amplify the signal up to 35.0 dB. We have analyzed the effects of fiber length, active ion concentration, pump power, and input signal power on the gain and the noise figure (NF).

Implementation of a Relay Module for Coverage Extension in Visible Light Communication (가시광 통신의 커버리지 확장을 위한 릴레이 모듈 구현)

  • Lee, Sang-Gwon;Lee, Jong-Sung;Oh, Chang-Heon
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.738-740
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    • 2017
  • Visible light communication is a communication method using light, and it has advantage of ensuring security in a single space as compared with RF communication. However, in the area outside the visible line of the light, communication disconnection occurs. Therefore, this paper proposes a relay module to overcome the coverage extension and communication disconnection phenomenon of visible light communication. The proposed relay module transmits and receives data of visible light communication by sequentially transmitting data packets including target ID through adjacent visible light module. Through experimentation of data transmission, we confirmed the extension of the transmission range and the data reception in the area outside the line of sight.

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Reducing the Effects of Noise Light Using Inter-Bit Noise Detection in a Visible Light Identification System (가시광 무선인식장치에서 비트간 잡음검출에 의한 잡음광의 영향 감소)

  • Hwang, Da-Hyun;Lee, Seong-Ho
    • Journal of Sensor Science and Technology
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    • v.20 no.6
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    • pp.412-419
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    • 2011
  • In this paper, we used the inter-bit noise detection method in order to reduce the effects of noise light in a visible light identification system that uses a visible LED as a carrier source. A visible light identification system consists of a reader and a transponder. When the enable signal from the reader is detected, the transponder encodes the response data in RZ(Return-to-Zero) bit stream and sends response signal by modulating a visible LED. The reader detects the response signal mixed with noise light, samples the noise voltage in each blank low time between data bits of the RZ signal, and recovers the original data by subtracting the sampled noise from the received signal. In experiments, we improved the signal-to-noise ratio by 20dB using the inter-bit noise detection method.

VOCs Reduction of Visible-light Responsive Photocatalyst coated nylon/polyester composite fiber for Vehicle Interior Parts and Materials (가시광 감응형 광촉매가 코팅처리된 자동차내장재용 Nylon/Polyester 복합섬유의 VOCs 저감)

  • Choi, Sei-Young
    • Elastomers and Composites
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    • v.49 no.1
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    • pp.53-58
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    • 2014
  • In this study, characteristics of visible-light responsive photocatalyst Weltouch, especially VOCs reduction of visible-light responsive photocatalyst coated nylon/polyester composite fiber for vehicle interior parts and materials were evaluated. Visible-light responsive photocatalyst Weltouch was observed for both anatase phase and rutile phase. It is activated by light longer than 420nm. VOCs and formaldehyde generated from visible-light responsive photocatalyst treated nylon/polyester composite fiber were reduced confirmly. Visible-light responsive photocatalyst was firmly attached to the surface of nylon/polyester composite fiber without elimination even after 25 times repeated washing. And washing durability of nylon/polyester composite fiber confirmed the excellence that reduction effects of VOCs after repeated washing has appeared as much as before washing.

Visible Light Communication LED driver For research to improve power (가시통신용 LED 드라이버 전력 효율 성능 향상을 위한 연구)

  • Kwon, Jae-hyun;Park, Keon-jun;Kim, Hyo-jun;Choi, Gil-Sang;Kim, Young-kab
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.15-16
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    • 2012
  • General lighting will be replaced into LED due to the high efficiency, low power consumption, long life than conventional light, moreover, since it is a basically semiconductor device that can convert the electric energy to visible light at a very high speed, using these characteristics can be performed communication modulation via the high-speed ON-OFF switching. Recently, visible light communication (VLC: Visible Light Communication) technology is received attention and there have been many researches. This paper is implemented media signal transmission by combining LED with VLC, a transmitter used the LED light-emitting device and receiver used an infrared sensor. In order to increase the efficiency of the communication system to improve the existing LED visible light communication driver of power conversion efficiency and thermal issues that is applied to the visible light communication in order to improve the speed of transmission media to research a new way of LED driver.

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A Passive Transponder for Visible Light Identification Using a Solar Cell (솔라셀을 이용한 가시광 인식용 수동형 트랜스폰더)

  • Lee, Seong-Ho
    • Journal of Sensor Science and Technology
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    • v.23 no.4
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    • pp.238-244
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    • 2014
  • In this paper, we introduce a new passive transponder that operates without external power in a visible light identification system. The transponder consists of a solar cell, a photodiode, a microprocessor, and a visible LED. When a reader sends light to the transponder, the solar cell generates current from the reader light and supplies power to the other elements in the transponder. At the same time, the photodiode detects the pulse in the reader light and initiates a microprocessor to generate and send a responding light to the reader. In experiments, we realized a passive transponder using a solar cell that operated at a distance of 1m without external power.

Flicker Prevention Through Edge-Pulse Modulation in a Visible Light Identification System (가시광 무선인식장치에서 가장자리 펄스변조를 이용한 플리커 방지)

  • Lee, Seong-Ho
    • Journal of Sensor Science and Technology
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    • v.29 no.3
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    • pp.180-186
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    • 2020
  • In this study, we applied edge-pulse modulation to prevent the flicker of light-emitting diode (LED) light in a visible light identification system. In the visible light transmitter, positive pulses were transmitted at the edges of the low-to-high transition points, and negative pulses were transmitted at the edges of the high-to-low transition points of the non-return-to-zero (NRZ) data waveforms. In the visible light receiver, the NRZ waveforms were regenerated by making low-to-high and high-to-low transitions at the point of the positive and negative pulses, respectively. This method has two advantages. First, it ensures that the LED light is flicker-free because the average optical power of the LED was kept constant during data transmission in the transmitter. Second, the 120 Hz optical noise from the adjacent lighting lamps was easily cut off using a simple RC-high pass filter in the receiver.