• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.10a
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• pp.240-240
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• 2009

오늘날 반도체 기술의 획기적인 발전에 의해서 마침내 에디슨의 탄소 필라멘트 백열전구를 대체할 수 있는 "반도체 필라멘트"라 불리는 고출력 백색 LED (lighting emitting diode)가 차세대 조명광원으로 급부상하고 있다. 백색LED를 생산하기 위한 공정에서 MOCVD (유기금속화학증착)장비를 이용한 공정은 기판의 온도 균일도를 향상시키는 것이 매우 중요하다. 균일한 기판 온도를 갖기 위한 조건으로 기판과 induction heater의 간격, 가스의 흐름, 기판의 회전, 유도가열코일의 디자인 둥이 장비의 설계 요소이다. 본 연구에서는 기관과 induction heater의 간격에 따른 온도를 thermal imaging camera (Fluke, Ti-10)을 이용하여 측정하였다.

• Economic and Environmental Geology
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• v.52 no.1
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• pp.13-28
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• 2019

This study analyzed precipitation environment, heavy metal contamination, and mineral composition of white, reddish brown and mixed precipitates occurring at the Osip stream drainage, Gangwondo. Furthermore, spectral characteristics of the precipitates associated with heavy metal contamination and mineral composition was investigated based on spectroscopic analysis. The pH range of the precipitates was 4.43-6.91 for white precipitates, 7.74-7.94 for reddish brown precipitates, and 7.59-7.9 for the mixed precipitates, respectively. XRF analysis revealed that these precipitates were contaminated with Ni, Cu, Zn, and As. The white precipitates showed high Al concentration compared to reddish brown precipitates as much as 3.3 times, and the reddish brown precipitates showed high Fe concentration compared to white precipitates as much as 15 times. XRD analysis identified that the mineral composition of the white participates was aluminocoquimbite, gibbsite, quartz, saponite, and illite, and that of reddish brown precipitates was aluminum isopropoxide, kaolinite, goethite, dolomite, pyrophyllite, magnetite, quartz, calcite, pyrope. The mineral composition of the mixed precipitates was quartz, albite, and calcite. The spectral characteristics of the precipitates was manifested by gibbsite, saponite, illite for white precipitates, goethite, kaolinite, pyrophyllite for reddish brown precipitates, and albite for the mixed precipitates, respectively. The spectral reflectance of the precipitates decreased with increase in heavy metal contamination, and absorption depth of the precipitates indicated that the heavy metal ions were adsorbed to saponite and illite for white precipitates, and goethite and magnetite for reddish brown precipitates.

• Korean Chemical Engineering Research
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• v.49 no.3
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• pp.320-324
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• 2011

TOPO/TOP capped CdSe nanoparticles were synthesized via thermal-solvent method. The 540 nm green and 620 nm red emitting CdSe nanoparticles were obtained by controlling the reaction time and temperature. Phosphor conversion white LED was produced combining a 460 nm emitting InGaN LED chip as an excitation source with 540 and 620 nm CdSe nanoparticles as phosphors. The single or double phosphor layer was fabricated by mixing with epoxy, and investigated the effects on the luminous properties of the white LED. The single phosphor layer white LED showed 5.78 lm/W with CIE of (0.36, 0.45) in reddish white, and the double phosphor layer white LED showed 7.28 lm/W with that of (0.32, 0.34) in pure white at 20 mA. When the 400 nm near-UV LED was applied to optical pumping source, the luminous efficiency of white LED was enhanced to 8.76 lm/W.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.19 no.2
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• pp.61-65
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• 2009

In this paper, we report on the growth and optical characteristics of white-LED without fluorescent material. The growth of DH(double heterostructure) with AlGaN active layer was performed on a n-GaN/(0001) $Al_{2}O_{3}$ by the mixed-source HVPE and multi-sliding boat. The CRI(color rendering index) of packaging device charged in the range 72-93 with CIE chromaticity coordinates(x=$0.26{\sim}0.34$, y=$0.31{\sim}0.40$). And CCT(correlated color temperature) values was measured $5126{\sim}10406K$ with increasing injection current. The CIE point of conventional phosphor white LED shifts blue region, but cm point of non-phosphor white LED shifts opposite direction. These results show the mixed-source HVPE can be possible to newly fabricate method of phosphor free white LED with high CRI value.

• The Korean Journal of Mycology
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• v.36 no.1
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• pp.31-35
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• 2008

To elucidate optimum light conditions for artificial cultivation of Grifola frondosa, the effects of light quality (blue, green, white) and light intensity (200, 500, 800, 1200 lux) on primordium formation, morphological properties and yield of fruiting bodies of G. frondosa using bag cultivation method were tested. Among three light sources, white light source ($400{\sim}620\;nm$) had a higher mushroom yield (242 g/bag) and a shorter cultivation period (52 days) than those of the others. In particular, blue light source ($400{\sim}560\;nm$) induced the morphology of wide and deep colored pilei in G. frondosa fruiting body. The experimental results on the appropriate light intensity indicated that 500 lux light was the most effective on mushroom production, whereas primordium formation was effective at 200 lux.

• The Journal of Engineering Geology
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• v.20 no.4
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• pp.381-390
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• 2010

This study assessed the hydrogeological characteristics of a seepage area of white leachate. The geological characteristics of the leachate were determined by a surface survey, and an electrical resistivity survey and borehole image processing system (BIPS) were applied to estimate the distribution of discontinuities, to assess the geological structure of the seepage areas. Fluctuations in groundwater level within boreholes were measured during periods of precipitation in the dry and wet seasons. The results show that electrical resistivity is lower in the seepage section than in non-seepage sections. The distribution of fracture zones and limestone cavities was inferred from the logging data and BIPS data. Variations in groundwater level and groundwater recharge, related to rainfall events, show the direct effect of rainfall events during the rainy season. We obtained a strong relationship between seepage amount and rainfall (correlation coefficients of 0.83-0.97).

• The Korean Journal of Mycology
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• v.24 no.4 s.79
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• pp.237-245
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• 1996

Esterase isozyme band patterns were compared between the wild strain and commercial strain of Flammulina velutipes. Monospores were isolated from wild strain. ASI4019 and their mating types were determined. We investigated the relationship between pigmentation on the plate and fruitbody color to understand genetic relationship among F. velutipes strains. Dikaryotic strains mated between nonpigmenting strains produced white fruitbodies. However dikaryon obtained from mating between nonpigmenting monokaryon and brown pigmenting monokaryon produced brown fruitbody as the dikaryon obtained from mating of brown pigmenting monokaryons. The white fruitbody from wild strain was distinguished from that of commercial strain. When the nonpigmenting wild monokaryon was mated with commercial monokaryon, pale brown mushroom was produced. The BC1F1 was obtained by mating the above mentioned $F_1$ with commercial monokaryon. Fruitbody color of BC1F1 shared two types; one strain with all pale brown fruitbodies, and the other strain with separated eight pale brown and two mixed type involving pale brown and white fruitbodies.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.36 no.4
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• pp.314-321
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• 2000

In order to obtain the fundamental data on the auditory thresholds of fishes for catching method using low frequency sound, the auditory thresholds of coralfish Chromis notatus were measured in the presence of masking noise in the spectrum level range of 73~83dB re l$\mu$Pa/√Hz by heartbeat conditioning technique using pure tones coupled with a delayed electric shock. Critical ratios were about 23~41dB at measurement frequency, The critical ratio increased almost linearly with increasing frequency from 500Hz. The noise spectrum level at the start of masking was about 60~65dB. This suggests that hearing of coralfish is masked in the natural environment with the noise spectrum level above 60dB. The sound pressure level of which the signal sound of 300Hz is recognized by coralfish under the ambient noise is above 88dB and the critical ratio of them is above 23dB. The hearing index of coralfish with ambient noise was 81.

• Journal of the Mineralogical Society of Korea
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• v.22 no.3
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• pp.199-206
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• 2009

The aim of this study is to investigate the relations among each white stone and their characteristics through the chemical and mineralogical analysis of them excavated from around some kilns in archaeological sites. Moreover it was intended to infer the function of kilns. Nine white stones were chosen from three different archaeological sites, the each name of which is Sanyang-ri, Youngdu-ri and Gwangdae-ri in Chungcheongnam-do. In the mineralogical characteristics of thin section, eight stones containing calcite are altered and recrystallized by metasomatism and hydrothermal process, and Calcites, major component minerals of limestone, were identified by the analysis of XRD. On the basis of this result, we can infer the stones to be classified into limestone groups. One the other hand, research revealed that one of the white stones was a white pelitic stone composed of quartz, microcline and muscovite. In the analysis of chemical composition, except for the white pelitic stone eight stones are mainly composed of CaO which is major component of Calcite. Besides, as a results of correlation analysis by using a chemical compositions of major and minor elements in white stones, little did each archaeological site have the relativity. In conclusion, each archaeological site was estimated that they would use a limestone ores extracted from different deposits, and there is a high possibility that the function of these kilns is to produce quicklime.

• KSBB Journal
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• v.11 no.6
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• pp.718-725
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• 1996

Old newsprint was deinked with endoglucanase, exoglucanase and their various compositions from Trichoderma viride. The yield decreased with an increase in enzyme concentration. Especially, it was the lowest in the treatment of endo-exo mixture(1:1). It may be regarded as a synergistic actions of the cellulase components. The brightness was the highest in pulp deinked with endo-exo mixture(1:1). Maximum brightness was observed when 0.5mg/mL of the endo-exo mixture was used. The physical strength increased with increasing concentration in exoglucanase. But, it decrease with increasing concentration in endoglucanse and endo-exo mixture(1:1). Also, we investigated the yield, brightness and physical strength of endoglucanase in combination with exoclucanase(12:1, 8:1, 4:l, 1:1, 1:4, 1:8, 1:12). Maximal deinking conditions, obtained at a specific optimal ratio of endoglucanase to exoglucanse are as follow ; 12:1 for yield, 12:1 for brightness, 4:1 for tensile strength, 12:1 for bursting strength, and 8:1 for tearing strength. These results indicated that the deinking depended largely upon the action of endoglucanase. Exoglucanase was occupying more than 60% of the total crude cellulase contents. Therefore, the most effective deinking must repress the action of exoglucanase.