• Journal of the Korean Solar Energy Society
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• v.22 no.1
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• pp.81-86
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• 2002

Solar daylighting system provides free and comfort lighting, but its design and control has been key issue due to heavy light collecting system. One of the solutions for the heavy weight issues would be using a light framed film such as fresnel and prism lens. This prototype system consists of light collector, light transformer and light guide luminaire. The light collector which is installed at window or the rooftop concentrates solar light, the collected beam is converted to suitable light by the light transformer. and the prism light guide luminaire has been used to distribute light emitted from light transformer for illumination. In this paper, the design concept and performance of light collector in this prototype system are presented.

• Korean Journal of Environmental Agriculture
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• v.32 no.2
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• pp.123-127
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• 2013

BACKGROUND: The incandescent bulb and compact fluorescent lamp are widely using as a light sources for daylength extension of chrysanthemum. But, these light sources consume a lot of electricity and have short longevity. A light-emitting diode (LED) is a semi conductor light source. LEDs have many advantages over incandescent light sources including lower energy consumption, longer lifetime. In this study, we investigated the intensity of red light to control flowering of chrysanthemum (Dendranthema grandiflorum cv. "Shinma") by using LEDs. METHODS AND RESULTS: The red (660 nm) and far-red (730 nm) light were irradiated subsequently to investigate photo-reversible flowering responses of chrysanthemum. The flowering of chrysanthemum was inhibited by night interruption with red light but subsequently irradiated far-red light induced the flowering of chrysanthemum. This photoreversibility, reversion of the inductive effect of a brief red light pulse by a subsequent far-red light pulse, is a property of photo responses regulated by the plant photoreceptor phytochrome B. Four different intensity of red light of 0.7, 1.4, 2.1, and $2.8{\mu}mol/m^2/s$ (PAR) were irradiated at growth room in order to determine the threshold for floral inhibition of chrysanthemum. Over $1.4{\mu}mol/m^2/s$ of the red lights irradiated chrysanthemums were not flowered. The plant length, fresh weight, number of leaves, and leaf area of chrysanthemum irradiated with red light were increased by 17%, 36%, 11%, and 48%, respectively, compared to those of compact fluorescent lamp. CONCLUSION(S): The red light and subsequential far-red light showed that the photoreversibility on flowering of chrysanthemum. The red light ($1.4{\mu}mol/m^2/s$ of red LEDs) and white light (50 Lux of compact fluorescent lamp) have the same effect on inhibition of flowering in chrysanthemum. Additionally, the red light increased the plant height and dry weight of chrysanthemum.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.137-138
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• 2015

The use of the cement and increased with the recent development of the construction industry. If the cement is the environmental problems caused by generating a large quantity of CO₂ and the production process. Accordingly, this study is the test to determine the sulfuric acid and hydrochloric acid resistance properties of the Light weight matrix product of blast furnace slag-based light. A result, the compression strength of the sulfuric acid and hydrochloric acid immersion showed alower strength than the Plain.

• Biomedical Science Letters
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• v.14 no.2
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• pp.91-96
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• 2008

Light Emitting Diode (LED) of 880 nm was used as a function of luminosity in culture of the photosynthetic bacteria including Rhodobacter sp.. An array of 880 run LED was driven with an energy density of $6.0mW/cm^2$. In processing time, we were able to show that the cell growth were gained of significant changes in the pigment and in the dry weight. And we also showed that photosynthetic bacteria had the resonable relativity of optical density to dry weight. LED-880nm is of great significance for the potential use of photo-bioreactor construction.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.114-115
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• 2014

Recently, the construction structure repeats the brilliant development including the shper high rising, high functionalization, environmental friendliness, conversion to ubiquitous, and etc. upon with the construction industry development and it is continually soothed. Meanwhile, as to the construction structure of the modern society, the research for corresponding to the box-frame construction way where the response to the diversity of the life of the occupant is difficult is needed. Thus, the lightweight of the structure is the important factor in order to secure the functionality. Therefore, this research tries to study the water absorption ratio and flexural strenght of the magnesium oxide light weight matrix according to the powdery modified sulfur addition ratio.

• Macromolecular Research
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• v.14 no.1
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• pp.81-86
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• 2006

Poly(fluorenylenevinylene-terphenylenevinylene) containing phenyl pendant group was synthesized by Suzuki coupling reaction and characterized by ${1}^H$-NMR, ${13}^C$-NMR, and IR-spectrum. The weight average molecular weight ($M_{w}$) of the obtained polymer was 31,000 with a polydispersity index of 1.9. The polymer showed good solubility in common organic solvents, and the solution and film emitted blue emission ($\lambda_{max}$=460 nm) on irradiation with UV light. The ITO/PEDOT/polymer/Al device fabricated using the polymer as an emitting layer emitted blue light with a maximum peak around 460 nm. The maximum efficiency of the device was 0.011$\%$.

• Journal of the Korean Society for Railway
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• v.3 no.2
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• pp.92-99
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• 2000

Composites are very useful material for light train carbody due to its high specific strength and lightweight characteristics. The composites, called 3-D board, are developed with a special stitching method. In this process, the glass fiber fabrics of skin material and foam core material are stitched together with glass fiber thread. The glass thread in Z-axis turns into FRP form. The conventional delamination problem can be solved with 3-D sandwich structure. In addition, with the lower density of foam, the weight of the panel and the operation expenses can be highly reduced. To evaluate the usefulness of the 3-D board, the double-deck light train carbody is studied. The stress analyses are carried out under various loads and boundary conditions with FEM Code, ANSYS. On comparing with the aluminum carbody, 3-D board carbody can be reduced by about 2 ton for the total weight of carbody.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.9
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• pp.1764-1768
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• 2009

As the demand of electric power is increasing rapidly, the need of the compact and light electric power device is also increased. Copper clad aluminum (CCA) is newly proposed electrical conductor, because of its light-weight and low-cost characteristics, to replace the existing conductor made of copper. This paper presents the salt-proof characteristics of the copper clad aluminum (CCA) to certificate long time safe operation of the newly proposed electrical conductor. The two types of the CCA conductor were tested in the neutral salt spray tester. The experimental results of two types of the CCA with salt spray were presented in this paper. The results comprise resistance measured data, micro picture of the selected surface, and component measured data according to the elapsed time. The period of the experiment was 1,000 hours. There was no evidence to show the corrosion of CCA during the whole period of the experiments.

• Macromolecular Research
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• v.15 no.3
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• pp.216-220
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• 2007

A new polyfluorene-based copolymer having 2-ethylhexyloxy-5-methoxy-l,4-phenylene as an electron donating group and 2,5-diphenyl-oxadiazole as an electron withdrawing group was synthesized by the Suzuki coupling reaction. The obtained copolymer was characterized by $^1H-NMR,\;^{13}C-NMR$, and IR-spectroscopy. The weight average molecular weight ($M_w$) of the obtained polymer was 18,600 with a polydispersity index of 1.5. The maximum photoluminescence of the solution and film of the polymer was observed at 453 nm and 456 nm, respectively. A double-layer device with the configuration, ITO/PEDOT/copolymer/Al, emitted blue light at 460 nm.

• Journal of the Korean Professional Engineers Association
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• v.9 no.1
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• pp.35-39
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• 1976

Possible methods of protection of non cellulosic fibers, particularly nylon filament yarn, from the damaging effects of light are discussed. Manganese acetate, cupricacetate, G1-06-196 and sodium phosphate are used as a light stabilizer for nylon filament yarn. The light stability of filament containing different weight of TiO$_2$ is increased as the following order: Bright>Semi-Dull>Full-Dull The protection effect against light according to the present of the light stabilizer in filament increased in the following order: Manganese acetate> Cupric acid> G1-06-196> Sodium phosphate Manganese acetate is shown to be the most effecting salt for protecting nylon against light. 15 ppm of the salt is shown to be effective enough for protecting nylon filament yarn against light.