• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1184-1186
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• 1995

The absorption spectra of synthesis of azobenzene containing long chain fatty acids were investigated by UV spectrophotometer in chloroform solution. Also, the pressure-area isotherms of the molecules on the water-air interface were obtained and the LB films were fabricated onto a quartz slides and quartz crystals by the conventional Langmuir-Blodggett(LB) method. The UV absorption spectra of Langmuir-Blodggett(LB) films on quartz slides have been measured. From these measurements, following conclusions were obtained. Azobenzene containing long chain fatty acids show a photoisomerization by irradiation of UV light and visible light alternatively. At the pressure-area isotherms, the value of surface pressure increment were decreased when the number of $C_n$ increased. Also the LB films show a photoisomerization characteristics. So the LB film of azobenzene containing long chain fatty acid has possibility to being applied to functional molecular device such as photomemory and light switching.

• Journal of the Korean Society of Costume
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• v.28
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• pp.205-212
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• 1996

This paper is to study the characteristics of fabrics dyed with astringent unripe persimmon juice. The cotton silk rayon and nylon fabrics were dyed with astringet unripe persimmon juice. The structures of natural fabrics dyed fabrics and dyed fabrics followed by washing were examined by scanning electron mi-croscopy. Surface reflexibility of VIS trans-mittance of UV VIS and NIR were analyzed. The study conclues as follows: 1. Colour of cotton fabrics dyed with persim-mon juice became darkended as a function of exposing time to sunlight. That colour was chaged after washing. 2. Blocking effect of ultraciolet light and visible ray was increased in all dyed fabrics. Especially dyed cotton fabric blocked UV light perfectly and the blocking effect was still remained after 9 washings. 3. Persimmon juice dyeing produced coating effect to fabrics besides dyeing effect accord-ing to the scanning electron micrographs. In a word the cotton fabric dyed with per-simmon juice has blocking effect of UV light stiffness. Therefore I think persimmon juice dyeing is a very useful textile finishing and ex-pect a wide application of the technique in fu-ture.

• Journal of environmental and Sanitary engineering
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• v.20 no.4 s.58
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• pp.51-58
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• 2005

Photocatalytic degradation using $TiO_2$ Particles suspended in a reactor was experimentally performed to degrade the formaldehyde of indoor pollutants. Exponential increase of degradation appears to prove light availability due to the scattering of W light by particles themselves. Comparative removal studies of formaldehyde were done in both cases of dipping and spraying immobilized techniques of $TiO_2$ Particles suspended in solution. Experiments were performed under several different experimental conditions such as initial concentration of formaldehyde, UV intensity and concentration of photocatalysts. Optimal conditions to degrade formaldehyde were obtained under the conditions of $30\;mg/cm^2$ concentration of catalyst and UV intensity of 30 Watt at the distance of 30 cm using immobilized technique by dipping coating.

• Journal of IKEEE
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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.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.517-520
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• 2001

The optical properties of $TiO_2$ thin films dispersed in epoxy film, which were prepared with bis-(4, 4'-P-toluenesulfonylacidic isoproplyidene) cycolhexadiol(BTSPC) and UVI 6990 in dry sol-gel process, were investigated. In the case of irradiating UV light on $TiO_2$ thin films, how many nanopartlcles of $TiO_2$ are dispersed in epoxy film was investigated by AFM. The absorption peak of the films was showed at 360nm. Squarylium dye was dispersed in $TiO_2$-epoxy film. Photodegration concerned with amount of dye and time of UV light irradiation was investigated. UV light irradiation on the film occurred dramatical photodegration.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.05a
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• pp.38-42
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• 1996

The pressure-area isotherm of monolayer at the air-water interface were obtained and the LB films were fabricated onto a quartz slides and quartz crystal by conventional Langmuir-Blodggett(LB) method. The UV absorption spectra of Langmuir-Blodggett(LB) film on quartz slides and spectrum of monolayer formed on quartz crystal have been measured. The photoisomerization of the long-chain fatty avid containing azobenzene were obtained by the application of UV and visible light. The reversibility of photoisomerization were more clear difference when the number of C$\_$n/ increased. At the pressure-area isotherms, the value of surface pressure increment were decreased when the number of C$\_$n/ increased, A surface pressure of 20mN/m was obtained as a proper one for a film deposition. The photoisomerization at LB films were also obtained by application of UV and visible light. So the LB film of long-chain fatty acid containing azobenzene has possibility to being applies to functional molecular devices such as photomemory and light switching.

• ETRI Journal
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• v.35 no.4
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• pp.566-570
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• 2013

In this paper, we demonstrate the capabilities of 380-nm ultraviolet (UV) light-emitting diodes (LEDs) using metal organic chemical vapor deposition. The epi-structure of these LEDs consists of InGaN/AlGaN multiple quantum wells on a patterned sapphire substrate, and the devices are fabricated using a conventional LED process. The LEDs are packaged with a type of surface mount device with Al-metal. A UV LED can emit light at 383.3 nm, and its maximum output power is 118.4 mW at 350 mA.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.517-520
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• 2001

The optical properties of TiO$_2$ thin films dispersed in epoxy film, which were prepared with bits-(4,4'-P-toluenesulfonylacidic isoproplyidene) cycolhexadiol(BTSPC) and UVI 6990 in dry sol-gel process, were investigated. In the case of irradiating UV light on TiO$_2$ thin films, how many nanoparticles of TiO$_2$ are dispersed in epoxy film was investigated by AFM. The absorption peak of the films was showed at 360nm. Squarylium dye was dispersed in TiO$_2$-epoxy film. Photodegration concerned with amount of dye and time of UV light irradiation was investigated. UV light irradiation on the film occurred dramatical photodegration.

• Korean Journal of Optics and Photonics
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• v.26 no.2
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• pp.83-87
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• 2015

This study was focused on developing an optical sensor that monitors ultraviolet (UV) light. Recently, we proposed and demonstrated a novel, highly sensitive UV sensor based on a fiber Bragg grating (FBG). To ensure that the incident UV light is focused on the FBG surface, the sensor was coated with an azobenzene polymer material that acts as a UV-induced stretchable functional material, in combination with a cylindrical focal lens. In this study we have improved the sensitivity of the sensor by employing a cylindrical focal mirror as a curved reflector, to refocus the UV light passing through the FBG. We considered the performance of several different types of reflectors and chose the optimal radius of curvature for the reflector. Compared to the UV sensor without an auxiliary device, the sensitivity of the FBG sensor with a focal lens and a curved reflector was 15 times as high.

• Food Science and Preservation
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• v.19 no.5
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• pp.645-651
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• 2012

The food functional properties of Pleurotus eryngii cultivated with different wavelengths of light-emitting diode (LED) light were analyzed in this study. The levels of total soluble solids of Pleurotus eryngii increased with all the LED lights, except mixed LED light ($B^*R$, $B^*G$ and $R^*G$). Thirty one kinds of components were detected by analyzing the free amino acids. The total free amino acid contents had a slightly higher tendency in the control group, but the ratios of eight essential amino acids among the total amino acids of Pleurotus eryngii cultivated under all the LED lights, including the blue light (blue, $B^*R$, $B^*G$ and $B^*R^*G^*U$) and the green light, were higher than that in the control group. K was the highest-content of mineral, and Mn was the lowest-content. The Ca content increased through cultivation under all the LED lights, except the blue light, but the Fe content (under the green and $B^*R$ lights), K content (under the red and UV-A lights) and Mg content (under the $R^*G$, UV-A and red lights) increased under the exclusive LED light. The total phenolic compounds increased by cultivation under all the LED lights, except the UV-A and mixed lights ($R^*G$ and $B^*R^*G^*U$). The DPPH radical scavenging activity was also improved by all the LED lights, except the mixed light ($R^*G$).