• 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.

• The Plant Pathology Journal
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• v.27 no.2
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• pp.103-109
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• 2011

The fungal genus Cercospora is one of the most ubiquitous groups of plant pathogenic fungi, and gray leaf spot caused by C. zeae-maydis is one of the most widespread and damaging foliar diseases of maize in the world. While light has been implicated as a critical environmental regulator of pathogenesis in C. zeae-maydis, the relationship between light and the development of disease is not fully understood. Recent discoveries have provided new insights into how light influences pathogenesis and morphogenesis in C. zeae-maydis, particularly at the molecular level. This review is focused on integrating old and new information to provide an updated perspective of how light influences pathogenesis, and provides a working model to explain some of the underlying molecular mechanisms. Ultimately, a thorough molecular-level understanding of how light regulates pathogenesis will augment efforts to manage gray leaf spot by improving host resistance and disease management strategies.

• ALGAE
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• v.38 no.2
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• pp.141-150
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• 2023

Light quality is a common environmental factor which influences the metabolism of biochemical substances in algae and leads to the response of algal growth and development. Pyropia yezoensis is a kind of economic macroalgae that naturally grows in the intertidal zone where the light environment changes dramatically. In the present study, P. yezoensis thalli were treated under white light (control) and monochromatic lights with primary colors (blue, green, and red) for 14 days to explore their physiological response to light quality. During the first 3 days of treatment, P. yezoensis grew faster under blue light than other light qualities. In the next 11 days, it showed better adaptation to green light, with higher growth rate and photosynthetic capacity (reflected by a higher rETR_max = 61.58 and E_k = 237.78). A higher non-photochemical quenching was observed in the treatment of red light than others for 14 days. Furthermore, the response of P. yezoensis to light quality also results in the difference of photosynthetic pigment contents. The monochromatic light could reduce the synthesis of all pigments, but the reduction degree was different, which may relate to the spectral absorption characteristics of pigments. It was speculated that P. yezoensis adapted to a specific or changing light environments by regulating the synthesis of pigments to achieve the best use of light energy in photosynthesis and premium growth and metabolism.

• Journal of the Korean Wood Science and Technology
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• v.34 no.2
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• pp.22-29
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• 2006

On purpose to reduce accumulated moisture and to prevent moisture condensation in a light-frame wall, thermal characteristics and moisture behaviors were investigated for four different wall assemblies; a) typical wall, b) addition of vapor retarder between the insulation and the gypsum board, c) addition of air gap for natural ventilation behind the siding, d) composition with b) and c). Each wall was tested under two climate conditions; 1) $20^{\circ}C$, 50% RH (indoor) and $30^{\circ}C$, 85% RH (outdoor), 2) $30^{\circ}C$, 85% RH (indoor) and $20^{\circ}C$, 50% RH (outdoor).The results showed that the typical wall assembly had poor resistance against moisture intrusion from the inside of building. Outdoor and indoor humidity caused the moisture condensations on the inside of the siding and the back surface of the sheathing respectively. The addition of a vapor retarder did not give significant improvement in preventing the moisture intrusion.

• Bulletin of the Korean Chemical Society
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• v.34 no.7
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• pp.2056-2062
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• 2013

The dihydroxy naphthalene/$TiO_2$ complexes with different substitution patterns were prepared by surface modification. X-ray diffraction, UV-Vis spectroscopy, photoluminescence, and X-ray photoelectron spectroscopy were used to characterize the prepared composite materials. The results indicated that the surface modification did not influence the crystallization of $TiO_2$. The visible-light absorbances of prepared dihydroxy naphthalene/$TiO_2$ complexes could be assigned to the ligand-to-metal charge transfer. The obtained catalyst exhibited outstanding photocatalytic activity and stability under visible light. A linear relationship existed between the percentages of hydroxynaphthalenes coordinated on $TiO_2$ surface and $H_2$ production ability. The substitution pattern of dihydroxy naphthalene and $CH_3OH$ content could also influence the photocatalytic performance remarkably. The photocatalytic $H_2$ production ability was further improved after loading with ultra low concentration of Pt, 0.02 wt %. The possible mechanism was proposed.

• Environmental Engineering Research
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• v.19 no.4
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• pp.317-329
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• 2014

The diversity of cyanobacteria in Sri Lanka was studied in different water reservoirs, paddy fields, brackish water and tsunami affected areas using light microcopy, 16S rRNA sequences, followed by phylogenetic analysis. Based on light microscopy, 24 genera were identified from environmental samples belonging to the orders Chroococcales, Oscillatoriales, Pleurocapsales and Nostocales. In cultures, 33 genera were identified from all five cyanobacterial orders, including Stigonematales. Based on 16S rRNA gene sequences and their morphology, two isolates were identified up to species level, 72 to genus level, one isolate up to family and 11 up to order level. Twelve isolates couldn't be assigned to any taxonomic level. The results of 16S rRNA gene sequences along with the phylogenetic analysis indicated that some cyanobacterial isolates could be accommodated to genus or order level. The 16S rRNA sequence analysis data in this study confirmed that order Nostocales and order Pleurocapsales cyanobacteria are monophyletic while orders Chroococcales, Oscillatoriales and Stigonematales cyanobacteria are polyphyletic. Polyphasic approach including the combination of light microscopy, cultures and the analysis of 16S rRNA gene sequences provide a promising approach to ascertain the diversity of cyanobacteria in different habitats.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.4
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• pp.76-81
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• 2011

This study was carried out in order to develop a speciality functional coated paper, which can be recognized under a ultraviolet lamp. The special fluorescent whitening agent (FWA) which absorbs ultraviolet light (397~410 nm) and emits it as yellowish light (570~500nm) was used. The special FWA was applied in a coating color in two ways: (1) direct application to a coating color as a FWA; (2) application on pigment surface, drying it and application it as a fluorescence whitening pigments (colored pigments). The effects of the special FWA on coating color properties were tested and the distribution of colored pigments in coated paper was evaluated under a ultraviolet lamp. The results showed that the colored pigments didn't affect on coating color properties. Experimental results showed the possibility of producing a security coated paper using the special FWA. To produce a speciality functional paper, it was found to be proper to apply the special FWA in the form of colored pigment.

• Bulletin of the Korean Chemical Society
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• v.34 no.12
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• pp.3671-3676
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• 2013

A series of carbon nanotube, $C_{60}$, and graphene modified $TiO_2$ nanocomposites were prepared by hydrothermal method. X-ray diffraction, $N_2$ adsorption, UV-Vis spectroscopy, photoluminescence, and Electrochemical impedance spectra were used to characterize the prepared composite materials The results reveal that incorporating $TiO_2$ with carbon materials can extend the adsorption edge of all the $TiO_2$-carbon nanocomposites to the visible light region. The photocatalytic activities were tested in the degradation of 2,4,6-trichlorophenol (TCP) under visible light. No obvious difference in essence was observed in structural and optical properties among three series of carbon modified $TiO_2$ nanocomposites. Three series of carbon materials modified $TiO_2$ composites follow the analogous tentative reaction mechanism for TCP degradation. GR modified $TiO_2$ nanocomposite exhibits the strongest interaction and the most effective interfacial charge transfer among three carbon materials, thus shows the highest electron-hole separation rate, leading to the highest photocatalytic activity and stability.

• Journal of Environmental Science International
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• v.20 no.12
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• pp.1599-1605
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• 2011

To evaluate heat environment surrounding plants diurnal change of leaf temperature in the broad-leaved deciduous and evergreen trees was measured with microclimatic environmental factors including global solar radiation, and upward and downward long wave radiation. Maximum daily solar radiation was 961.2 and 976.3 w/$m^2$ in August 9 and 23, respectively. Upward long wave radiation was slightly higher than downward long wave radiation, showing 404.2 w/$m^2$ in August 9 and 394.5 w/$m^2$ in August 23. In addition, daily maximum vapor pressure deficit was 5.42 and 6.84 kPa in August 9 and 23, respectively, indicating high evaporative demand. Quercus glauca and Acer mono was differently responded to changing light regimes. On August 9, leaf temperature at the top-positioned leaves of Acer plants was higher than air temperature as well as those of Quercus plants in the morning. This indicates that stomata in Acer plants were closed by heat stress or water stress in the morning, while Quercus plant maintained active transpiration by opening stomata. These results indicated that improved light regimes such as gap opening in the closed forest may not always affect positively in the physiology of understory plants.

• Bulletin of the Korean Chemical Society
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• v.33 no.1
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• pp.199-203
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• 2012

A modified sol-gel method and $N_2$-plasma treatment were used to prepare bulk and surface doped N-$TiO_2$, respectively. XRD, TEM, UV-vis spectroscopy, $N_2$ adsorption, Elemental Analyzer, Photoluminescence, and XP spectra were used to characterize the prepared $TiO_2$ samples. The N doping did not change the phase composition and particle sizes of $TiO_2$ samples, but increased the visible light absorption. The photocatalytic activities were tested in the degradation of an aqueous solution of a reactive dyestuff, methylene blue, under visible light. The photocatalytic activity of surface doped N-$TiO_2$ prepared by $N_2$-plasma was much higher than that of bulk doped N-$TiO_2$ prepared by sol-gel method. The possible mechanism for the photocatalysis was proposed.