• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.4
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• pp.297-302
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• 2011

According to the standards for district heating substation established by Korea District Heating Corporation, water heating supply systems at over 150 Mcal/h capacity must employ the 2-stage heat exchanger that improves the system efficiency by reusing the heat included in the return water of district heating system already used for space heating. In this paper, the operating characteristics of the system in accordance with the load distribution of two heat exchangers for pre-heating and re-heating cold city water are investigated. The results including mass flow rate, return temperature etc. help to manage district heating system economically.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.263-263
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• 2008

This paper describes the electrical strength of a toughened glass stem insulators employed for electric railways. The broken glass stem insulators for comparison were taken at site. According to the international standards, electrical strength tests with 60[Hz] voltage and with impulse voltage were carried out to them under dry and wet condition and the results were corrected by considering the temperature and humidity factors. Based on the experimental results, the electrical strength of broken glass stem insulators was compared with those of sound ones and surface flashover characteristics were also discussed. As a result, it was confirmed that the electrical discharge is formed by bridging each end of the insulator shell. The experimental results are expected to be utilized as data for electrically identifying the failure causes of glass insulators.

• Korean Institute of Interior Design Journal
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• v.15 no.2 s.55
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• pp.138-149
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• 2006

A museum's collections is fundamental factors to construct important activity of museum performing a role as cultural facility for learning, education and research. Therefore, conservation of collections through appropriate environments is previously established in step of planing a museum. Hereby, the purpose of this study is to set up the classification of collections and suggest a useful guidance of the storage division in a domestic museum. The results of this study are as follows. First, the main factors of deterioration are temperature and relative humidity in a museum storage, so classification of collections should be set up according to the objective standards of these factors. Second, the classification of collections can be performed as follow: the group for nonorganic materials subdivide metal, chinaware, earthenware, and jade stone, the group for organic materials subdivide leather hair paper fabric, bone horn shell mound and wood herbage and the group for composed materials. Third, for storage division of a domestic museum, basically has to consider that it is reasonable to plan $4{\sim}5$ storages in metal, jade stone, chinaware earthenware, and organic materials of $1{\sim}2$ units in case of a serial of history like archaeological, antique museum. And in case of folk relics of modern and contemporary arts are collected, it is reasonable to plan over 5 storages add composed materials to foregoing classification.

• Korean Journal of Crystallography
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• v.13 no.2
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• pp.63-68
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• 2002

Zn/sub 2-x/Mn/sub x/SiO/sub 4/ phosphors for PDP were synthesized by solid state reaction method. The effects of firing temperature, ratio of hydrogen gas to nitrogen for heat treatment and concentration of activator and co-dopants on the luminous properties have been investigated. It was found that the phosphor fabricated at 1400℃ with x = 0.002 Mn concentration had a maximum brightness. Luminous properties of a phosphor were improved when Cr/sup 3＋/ was added as a co-dopant rather than other co-dopants.

• Journal of the Optical Society of Korea
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• v.17 no.5
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• pp.376-383
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• 2013

The design of the LEDs lighting in general household illumination was proposed and compared with the fluorescent lighting in this study. Using the LED as a light source would promote energy saving lighting for household illumination purposes. We used the LightTools and DIALux software to design and simulate different standards of illuminance, different correlated color temperatures and different color rendering indices for household environments. The power consumption and efficiency of traditional illuminated light sources and an LED light source with the same standard of illuminance for lighting the household environment were analyzed and compared with each other. Finally, our results show the advantages of using white-light LEDs for lighting and household illumination.

• Korean Journal of Plant Resources
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• v.20 no.6
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• pp.553-557
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• 2007

The purpose of this study is to establish an extraction and analysis method for $\alpha$-tocopherol, and to then distinguish among varieties. The $\alpha$-tocopherol contents of 22 varieties of peanut seeds were analyzed by HPLC. Peanut seeds of cv. Palkwang were processed in two ways, by boiling and roasting. The $\alpha$-tocopherol contents of the two types of peanuts were compared with fresh seeds without any processing. $\alpha$-Tocopherol was detected at a retention time of 2.95 minutes. Five standards of $\alpha$-tocopherol covering a range of $20{\sim}100{\mu}g/ml$ were made up in 2% isopropyl alcohol/n-hexane and analyzed in duplicate. The $\alpha$-tocopherol contents differed according to extraction temperature. The contents were $85{\mu}g/g$ or less at $10^{\circ}C\;and\;20^{\circ}C$ and $94{\mu}g/g$ at $30^{\circ}C$, but they were decreased at $40^{\circ}C$ or higher. The $\alpha$-tocopherol contents in 22 peanut varieties were $61.36{\sim}96.80{\mu}g/g$ according to variety. Fresh peanuts contained $106.7{\mu}g/g$ of $\alpha$-tocopherol, while boiled peanuts contained $108.8{\mu}g/g$ of $\alpha$-tocopherol, and roasted peanuts contained $109.2{\mu}g/g$ of $\alpha$-tocopherol.

• Journal of the Korean Magnetics Society
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• v.21 no.4
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• pp.141-146
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• 2011

We will introduce the surface magneto-optic Kerr effect (SMOKE), which is one of the most helpful experimental methods in the area of surface magnetism for the last two decades. The basic magnetic characteristics of magnetic thin film is the most essential part for the further understanding and application. For example, the possibility of the realization of ferromagnetism for a single layer of iron, its Curie temperature far below that of bulk iron, and the direction of easy axis are the fundamental questions for the spintronic application. SMOKE is an efficient method to answer for the questions above.

• The Korean Journal of Ceramics
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• v.6 no.4
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• pp.354-358
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• 2000

The SnO$_2$film was deposited on a corning glass 1737 substrate by plasma enhanced chemical vapor deposition using a gas mixture of SnCl$_4$, $O_2$, and Ar. The film thickness was measured using $\alpha$-step and was about 9400$\AA$. The conventional X-ray diffractometry and pole figure attachment were used to refine the crystal structure of SnO$_2$ thin film. Six pole figures, (200), (211), (310), (301), (321), and (411), were measured with CoK$_\alpha$ radiation in reflection geometry. The X-ray diffraction data were measured at room temperature using CuK$_\alpha$ radiation with graphite monochromator. The agreement between calculated and observed patterns for the normal direction of SnO$_2$ thin film was not satisfactory due to the severely preferred orientation effect. The Rietveld refinement of heavily textured SnO$_2$ thin film was successfully achieved by adopting the pole density distribution of each reflection obtained from the inverse pole figure as a correction factor for the preferred orientation effect. The R-weighted pattern, R$_wp$, was 15.30%.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.3
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• pp.186-193
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• 2020

We investigate a fog-detection CCT control system using low deck lighting as a solution to the forward visibility of pole-type street lamps employed on existing roads. The lighting standards were met with a light source that has less compared with those of pole-type street lamps. The results show that the transmission rate was increased by changing the color temperature by automatically recognizing fog in bad weather and minimizing the phenomenon of lighting. In addition, it was allowed to create a safer and more comfortable driving environment for drivers owing to flicker or light pollution of existing pole-type street lamps. As a result, if lighting is used at a lower level than pole-type street lamps, the accident rate caused by securing the driver's forward visibility can be reduced sharply and existing problems can be resolved.

• Journal of Biosystems Engineering
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• v.32 no.4
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• pp.237-246
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• 2007

In this study, the microwave free-space transmission technique was used to measure the dielectric property of powdered food at microwave frequencies. The sample holder was designed and fabricated to transmit the microwave signals ranging from 1 to 15GHz. From the microwave propagation theory the equation expressing the dielectric property of powdered food was derived and validated by standard dielectrics. The dielectric property of powdered food such as wheat flour, coffee powder and milk powder was measured and analyzed. In the uniform range of bulk density of material, the real parts of permittivity of the food samples increased with the increase of moisture content, bulk density and temperature of the samples. The propagation properties such as attenuation and phase shift increased linearly as the moisture density of the food samples increased. As a measuring frequency of the moisture content, the X-band was recommended.