• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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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.

• 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.

• KIEE International Transactions on Electrophysics and Applications
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• v.4C no.3
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• pp.101-105
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• 2004

The efficient power MOSFET inverter applied for a simple and low cost power supply is proposed for driving the dielectric barrier discharge (DBD) lamp load. For decades, the DBD phenomenon has been used for ozone gas production in industry. In this research, the ultraviolet and visible light sources utilizing the DBD lamp is considered as the load for solid-state high frequency power supply. It is found that the simple voltage-source single-ended quasi-resonant ZVS inverter with only one active power switch could effectively drive this load with the output power up to 700 W. The pulse density modulation based control scheme for the single-ended quasi-resonant ZVS inverter using a low voltage and high current power MOSFET switching device is proposed to provide a linear power regulation characteristic in the wide range 0-100％ of the full power as compared with the conventional control based Royer type parallel resonant inverter type power supplies.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.5
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• pp.277-284
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• 2015

The humans are under attack involving the hazardous environment and pathogen/biotoxin aerosol that is realistic concerned. A portable, fast, reliable, and cheap Pathogen and Biotoxin Aerosol threat Detection(PBAD) trigger is an important technology for detect-to-protect and detect-to-treat system because the man-made biological terror is a fast and lethal infection. The ultraviolet C(UVC) wavelengths light source is key issue for PBAD that is sensitive because of strong fluorescence cross section from fluorescent amino acids in proteins such as tryptophan and tyrosine. The UVC-light emitting diode(LED) is emerging light source technology as alternative to laser or lamps as they offer several advantages. This paper discussed about the design consideration of UVC-LED for the PBAD system. The UVC-LED and PBAD technology, currently available or in development, are also discussed.

• Journal of environmental and Sanitary engineering
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• v.14 no.4
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• pp.143-149
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• 1999

In the tungsten industry as light source material, tungsten filament which used as light source material could form after molybdenumwire which used as the center supporter for coil shape tungsten wire was removed. This process uses hydrogen peroxide, Ozone and UV(Ultraviolet)Lamp, for the quantity of hydrogen peroxide decrease. The results were as follows : 1. An incandescent electric Lamp type : FL(FL-20) type : A standard of commodity (P.W.: $19{\pm}1.0mg$, $C.R:4.5{\pm}0.3{\Omega}$) 1) Only hydrogen peroxide treated ; Reaction Time : 65Min., P.W.: 18.60mg, $C.R.:4.60{\Omega}$ 2) Ozone/Ultraviolet/70% of hydrogen peroxide; Reaction Time : 64Min., P.W.: 18.61mg, C.R.: $4.61{\Omega}$ 2. A Fluorescent Lamp Type : GLS(GLS-40) Type : A standard of commodity(P.W.: $11.8{\pm}0.2mg$$65{\pm}1.5{\Omega}$) 1) Only hydrogen peroxide treated ; Reaction Time: 72Min, P.W.:11.88mg, C.R.: $65.62\Omega$ 2) Ozone/Ultraviolet/70% of hydrogen peroxide;Reaction Time:71Min., P.W.:11.88mg, C.R.: $65.63\Omega$

• Journal of Sensor Science and Technology
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• v.16 no.4
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• pp.307-312
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• 2007

The films of Er-doped ZnO (ZnO:Er) were prepared onto MgO wafers by ultrasonic spray pyrolysis at $550^{\circ}C$. The concentration of Er in the deposition source varied from 0.5 wt% to 3.0 wt%. The crystallographic properties and surface morphologies of the films were investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. The properties of photoluminescence (PL) for the films were investigated by dependence of PL spectra on the Er concentration in the films. The films were grown as polycrystalline with a dominant direction of [002]. The grain size of the films were reduced by Er-doping. Er-doping enhanced the ultraviolet emission of ZnO:Er films. The ZnO:Er films prepared with the deposition source of 2.0 wt% Er showed the strongest ultraviolet light emission peak among the films in this study.

• Korean Journal of Optics and Photonics
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• v.35 no.5
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• pp.235-240
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• 2024

Since the coronavirus pandemic, research and application of space sterilization effects using UV light sources have been rapidly increasing. In this paper, the space-sterilization effect of UV LED light sources that can be built into indoor environmental systems or lighting devices is quantitatively analyzed through an illumination optical approach. Through this, it is possible to establish a foundation for optimizing the sterilization effect in indoor spaces in the 275±5 nm wavelength range, which is known to have excellent space-sterilization power.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.421-422
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• 2011

The first part is about development of a liquid target for a neutron source, which is designed to overcome many of the limitations of traditional beam-target neutron generators by utilizing a liquid target neutron source. One of the most critical aspects of the beam-target neutron generator is the target integrity under the beam exposure. A liquid target can be a good solution to overcome damage to the target such as target erosion and depletion of hydrogen isotopes in the active layer, especially for the one operating at high neutron fluxes with no need for water cooling. There is no inherent target lifetime for the liquid target neutron generator when used with continuous refreshment of the target surface exposed to the energetic beam. In this work, liquid target containing hydrogen has been developed and tested in vacuum environment. Potentially, liquid targets could allow a point neutron source whose spatial extension is on the order of 1 to $10{\mu}m$. And the second is about the vacuum ultraviolet (VUV) spectrometer which is designed as a five-channel spectral system for ITER main plasma measurement. To develop and verify the design, a two-channel prototype system was fabricated with No. 3 (14.4 nm~31.8 nm) and No. 4 (29.0 nm~60.0 nm) among the five channels. For test of the prototype system, a hollow cathode lamp is used as a light source. The system is composed of a collimating mirror to collect the light from source to slit, and two holographic diffraction gratings with toroidal geometry to diffract and also to collimate the light from the common slit to detectors. The two gratings are positioned at different optical distances and heights as designed. To study the appropriate detector for ITER VUV system, two different electronic detectors of the back-illuminated charge coupled device and the micro-channel plate electron multiplier were installed and the performance has been investigated and compared in the same experimental conditions. The overall system performance was verified by measuring the spectrums.

• Journal of Korean Society on Water Environment
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• v.26 no.4
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• pp.707-712
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• 2010

Nitrogen-doped $TiO_2$ particles have been successfully prepared using titanium tetraisopropoxide as the Ti source and urea as the nitrogen source. As-prepared nitrogen-doped $TiO_2$ was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller method (BET) and ultraviolet-visible light (UV-vis) absorption spectra techniques. Photocatalytic degradation of Methylene Blue (MB) has been carried out in both solar light (UV-vis) and the visible region (${\lambda}=420nm$). Nitrogen-doped $TiO_2$ exhibits higher activity than the commercial $TiO_2$ photocalyst, particularly under visible-light irradiation because bandgap of nitrogen-doped $TiO_2$ becomes remarkably decreased.

• Journal of Biosystems Engineering
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• v.35 no.2
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• pp.124-131
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• 2010

Chlorophyll fluorescence has been researched for assessing fruit post-harvest quality and condition. The objective of this preliminary research was to investigate the potential of fluorescence spectroscopy for measuring apple fruit quality. Ultraviolet (UV) and blue light was used as an excitation source for inducing fluorescence in apples. Fluorescence spectra were measured from 'Golden Delicious' (GD) and 'Red Delicious' (RD) apples using a visible/near-infrared spectrometer after one, three, and five minutes of continuous UV/blue light illumination. Standard destructive tests were performed to measure fruit firmness, skin and flesh color, soluble solids and acid content from the apples. Calibration models for each of the three illumination time periods were developed to predict fruit quality indexes. The results showed that fluorescence emission decreased steadily during the first three minutes of UV/blue light illumination and was stable within five minutes. The differences were minimal in the model prediction results based on fluorescence data at one, three or five minutes of illumination. Overall, better predictions were obtained for apple skin chroma and hue and flesh hue with values for the correlation coefficient of validation between 0.80 and 0.90 for both GD and RD. Relatively poor predictions were obtained for fruit firmness, soluble solids content, titrational acid, and flesh chroma. This research has demonstrated that fluorescence spectroscopy is potentially useful for assessing selected quality attributes of apple fruit and further research is needed to improve fluorescence measurements so that better predictions of fruit quality can be achieved.