• Rapid Communication in Photoscience
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• v.2 no.2
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• pp.64-66
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• 2013

Photoreduction of $CO_2$ into hydrocarbon fuels on the surface of photocatalyst is one of the breakthroughs in the field of photocatalysis. At present various approaches have been investigated with the aim of increasing the $CO_2$ conversion efficiency. The reactor for photoconversion of $CO_2$ plays a vital role in experimental setup. In this work an attempt was made to testify a newly designed the photoreactor for conversion of $CO_2$ into useful products. The photoreactor was specifically designed for simple operation bearing features of temperature and pressure control. The reactor has been tested successively with the standard titania, Degussa P25 yielding methane with moderate production rate of 30.8 $ppm{\cdot}g^{-1}{\cdot}h^{-1}$ under UV lamp with 365 nm wavelength. The methane yield obtained is comparable to the values reported in literature. Thus we anticipate that this experimental setup equipped with newly designed photoreactor can yield competitive amounts of fuels from $CO_2$ photoredcution via 365 nm UV light illumination on various photocatalysts.

• Journal of the Korean Society of Food Science and Nutrition
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• v.13 no.1
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• pp.1-8
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• 1984

The tools and techniques for measuring the spectral distribution of light emitted by, transmitted by, or reflected from food surfaces are described for determining the extent to which original natural color is preserved in processing and subsequent storage of foods. Color differences may be evaluated indirectly in terms of some physical characteristic of the sample or extracted fraction thereof that is largely responsible for the color characteristics. For evaluation more directly in terms of what the observer actually seen, color differences are measured by reflectance spectrophotometry and photoelectric colorimetry and expressed as differences in psychophysical indexes such as luminous reflectance and chromaticity. The standard system, against which other systems could be compared, is the one recommended by the International Committee on illumination and which is based on the 'standard observer', which is a simulated standard eye, consisting of three primary color filters Z, with X being essentially amber in color, Y, green and Z, blue. Any spectrophotometric curve of reflectance obtained from the surface of an object can be integrated in terms of X, Y and Z. Psychophysical notation may be converted by standard methods to the colorimetrically more descriptive terms of Munsell hue, value and chroma.

• Journal of environmental and Sanitary engineering
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• v.20 no.3 s.57
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• pp.1-9
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• 2005

Recently, indoor air quality (IAQ) in workplace, residential environments and schools has been concerned of people, scientists and related the public, and has recognized the healthy effectsrelated to IAQ, specially in schools in Korea. Therefore, objectives of this study in this study were to measure and compare the perception of TAQ of selected air pollutants in Seoul from April to September 2004. Measurement place measured 2 schools of Seoul and local 9 schools (by Kyonggi Province, Chungchong-bukdo Chungchong-namdo, Chollado-bukdo, Cholla-namdo, Kyongsang-bukdo, Kyongsang-namdo, Kwangju, schoolin Pusan each 1 place). Temperature, humidity, illumination, carbon monoxide, carbon dioxide, TBC (total bacteria count), noise, PM10, TVOC(total volatile organic compounds), HCHO (formaldehyde) were measured simultaneously. Also, we Performed a questionnaire survey of 250 students and 50 teachers about their awareness for the importance of IAQ in their schools. Among this article, we handled noise, carbon monoxide, carbon dioxide, TBC, TVOC, HCHO, PM 10 in our conclusion. Major results were as follows ; Carbon monoxide (CO) was lower than indoor air standard of Korea. Carbon dioxide $(CO_2)$ appeared that 4 schools among our sample target school exceeded in normal standard. 4 schools were almost similar with normal standard. TBC appeared that 7 schools among 11 schools were higher than standard. Noise measured school's mean value passed exceeded standard. And school which passed over standard appeared to 7 schools among 11 schools. HCHO was exceeded 4 schools by standard that excess and certainly interrelation between school's establishment year and facilities of construction was detected. PM10 was exposed all schools by fitness in standard. TVOC appeared that 9 schools among 11 measurement school was exceeded health effect standard of Japan.

• Bulletin of the Korean Chemical Society
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• v.33 no.2
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• pp.469-472
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• 2012

Intensity modulated photocurrent spectroscopy and intensity modulated photovoltage spectroscopy were investigated to measure the dynamic response of charge transfer and recombination in the standard, $TiCl_4$-treated and the combined scattering layer electrode dye-sensitized solar cells (DSSCs). IMPS and IMVS provided transit time ($\tau_n$), lifetime ($\tau_r$), diffusion coefficient ($D_n$) and effective diffusion length ($L_n$). These expressions are derived that generation, collection, and recombination of electrons in a thin layer nanocrystalline DSSC under conditions of steady illumination and with a superimposed small amplitude modulation. In this experimental, IMPS/IMVS showed that the main effect of $TiCl_4$ treatment is to suppress the recombination of photogenerated electrons, thereby extending their lifetime. And the Diffusion coefficient of combined scattering layer electrode is $6.10{\times}10^{-6}$ higher than that of the others, resulting in longer diffusion length.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.179-182
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• 2007

Recently, the circuits of fluorescent light-switches are separated for window-light, middle-lights, or corridor-light, etc in most offices and classrooms in this country. Although it is clean and shiny - more than standard intensity of illumination, it is common that fluorescent lights on the side of window are lighted. In this case, we can use a fluorescent light with a sensor, which is turned on and off automatically according to the amount of sunlight. I think that this plan can save energy, reduce the budget, and increase the effect of education. and so I studied on this plan.

• The Journal of the Korean dental association
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• v.55 no.8
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• pp.556-564
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• 2017

Endodontic surgery is a procedure to treat apical periodontitis or abscess in cases that did not heal after nonsurgical treatment or retreatment. This might include situations with persistent intracanal infection after root canal treatment. Other reasons might be found in extraradicular infection, such as bacterial biofilm on the apical root surface or bacteria within the lesion. For many years, the treatment standard was the traditional approach with surgical burs and amalgam for root-end filling. Endodontic microsurgery is the most recent step in the evolution of endodontic surgery, applying not only ultrasonic tip and biocompatible filling materials but also incorporating high-power magnification and illumination. Although many studies have been published that advocate the use of modern technique, the traditional techniques are still widely used in the surgery community. The purpose of this study was to demonstrate the endodontic microsurgery procedure including the root-end preparation and filling with the use of a surgical operating microscope.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.4 no.3
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• pp.26-36
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• 1990

Poor quality and lower levels of lighting can produce severe problems in visual environment including glare, veiling reflections and contrast. This study aims to evaluate the lighting environment around VDTs. For the purpose, brightness contrast on screen, Reyboaed, and document, and their illumination were measured and compared to German Standard. The lighting environment of two offices untilizing VDTs were significantly different according to the daylight direction; the side and the frontward.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.4 no.1
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• pp.31-40
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• 1990

Poor quality and lower levels of lighting can produce severe problems in visual environment including glare, veiling reflections and contrast. This study aims to evaluate the lighting environment around VDTs. For the purpose, brightness contrast on screen, Reyboard, and document, and their illumination were measured and compared to German Standard. The lighting environment of two offices untilizing VDTs were significantly different according to the daylight direction; the side and the frontward.

• Journal of Sensor Science and Technology
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• v.21 no.1
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• pp.7-12
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• 2012

In this paper, we propose a 4-transistor active pixel sensor(APS) with a novel correlated double sampling(CDS) circuit for the purpose of extending dynamic range. Dual sampling techniques can overcome low-sensitivity and temporal disparity problems at low illumination. To accomplish this, two images are obtained at the same time using different sensitivities. The novel CDS circuit proposed in this paper contains MOS switches that make it possible for the capacitance of a conventional CDS circuit to function as a charge pump, so that the proposed APS exhibits an extended dynamic range as well as reduced noise. The designed circuit was fabricated by using $0.35{\mu}m$ 2-poly 4-metal standard CMOS technology and its characteristics have been evaluated.

• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.378-381
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• 2015

To produce low cost and efficient photovoltaic cells, inorganic-organic lead halide perovskite materials appear promising for most suitable solar cells owing to their high power conversion efficiency. Most recent research showes that formamidinium lead iodide ($FAPbI_3$) with methylammonium lead bromide ($MAPbBr_3$) improves the power conversion efficiency of the solar cell to more than 18 per cent under a standard illumination because incorporated $MAPbBr_3$ makes $FAPbI_3$-relatively unstable but comparatively narrow band gap-more stable composition. In respect to first principle study, we investigated band gap of $MAPbI_3$, $FAPbI_3$, $MAPbBr_3$, $(FAPbI_3)_{0.89}-(MAPbBr_3)_{0.11}$ and 0.615(eV), 0.466, 1.197, 0.518 respectively through EDISON DFT software. These results emphasize enhancing structure stability is important factor as well as finding narrow band gap.