• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.80-81
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• 2017

The study conducted a thermal conductivity test of magnesium oxide to manufacture boards using absorbent to produce board of radon gas molecules that are absorbed into the indoor air pollutants, which are currently in question, among other indoor air pollutants. Using material are the vermiculite and anthracite, in case of the vermiculite, which results in large porosity due to the expansion, in case of the anthracite, which characteristic generates pore on the matrix. As a result of the experiment, the lowest value was given to 0.6161 kcal/mh℃ which adding vermiculite 10% and anthracite 40%. However, adding vermiculite 40% and anthracite 10%, slightly higher 0.7229 kcal/mh℃, it is deemed the anthracite has more porosity than the vermiculite and, it judged that pore occurrence during the mixing process, appeared that the heat conductivity go down.

• Journal of Electrical Engineering and Technology
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• v.1 no.4
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• pp.496-502
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• 2006

In this paper, we studied the development of the electronic ballast for 250W MH (Metal-Halide) lamps. We were able to improve the input power factor by using a PFC IC. To provide the lamp with the rated voltage required, we used the buck-type dc-dc converter. The stress of the switching devices in the inverter could be reduced by this method. To eliminate the acoustic resonance phenomena of MH lamps, the voltage of the lamp added the high frequency sine-wave to the low frequency square-wave by using the full bridge typed inverter. We have developed a simple igniter using the L and C elements. We could control the dimness of the lamp by varying the output voltage of the buck converter. The buck converter output voltage could be controlled by using a microprocessor.

• Korean Journal of Microbiology
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• v.29 no.1
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• pp.63-68
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• 1991

Several arsenic compound-resistant bacteria were isolated from Jung-Rang stream. The isolates, D-3, D-12, and D-14 were characterized phenotypically and genetically, and identified as Serratia liquefaciens, Klebsiella oxytoca, and Klebsiella pneumoniae, respectively. A plasmid of 67kb was found in Klebsiella oxytoca D-12 and designated as pMH12. Transfer of this plasmid from D-12 to E. coli HB101 was occurred, and the resulting transconjugant strains expressed the same level of heavy metal resistance as the donor strain. The physical presence of this plasmid in transconjugant was detected with agarose gel electrophoresis. Arsenite-sensitive derivatives of isolate D-12 were obtained with Mitomycin C treatment which cured pMH12. Antibiotics and heavy metal resistances were also examined to be used as a proper marker for the isolates in gene cloning. Isolate D-12 has resistance to several heavy metal ions such as $Cd^{2+}$ , $Zn^{2+}$ and $Hg^{ 2+}$ Also, all the other arsenite resistant isolates showed resistance to several heavy metal ions and antibiotics.

• Korean Journal of Plant Resources
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• v.7 no.1
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• pp.1-5
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• 1994

To decrease the bolting rate of Angelica gigas, The growth inhibitors such as MH, Pp333 (paclobutrazol) and CCC(chloroniequat or Cycocel) were treated twice with the interval of 20 days atthe forming stage of flower bud.Growth and bolting rate in plot treated inhibitors were retarded and decreased, and the yield ofroots was also decreased compared with non - treatment. The treatments of MH and Pp333 amongthree inhibitors showed the better effects in decreasing the bolting than that of CCC, but they did notshow the significant in the yield and contents of decursin among each of them.In order to improve the decreasing effects by chemicals, selection of suitable reagents, concentrationand number of treatment should be investigated.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.10
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• pp.1947-1953
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• 2009

Metal halide (MH) lamps have been largely used due to high luminous efficiency, good color rendering, and long life. Since the metal halide lamps have problems of high ignition voltage and acoustic resonance. Thus, the design of ballast is very difficult for engineers. This paper proposes prototype of electric ballast in order to solve above two problems. The proposed electric ballast is consisted of EMI filter, full wave rectifier circuit, active PFC, DBI(Dual Buck Inverter), dimming circuit and ignitor circuit. The DBI supplies both rectangular voltage and current to the lamp. As the result of the experiment, the acoustic resonance was eliminated and the ignitor circuit was designed to generate high ignition voltage than 5kV. It makes the dimming circuit possible to control the lamp power in range between 230W and 350W.

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.464-466
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• 1993

In this paper, a peak detection algorithm having high reliability is proposed. The peak detection algorithm is implemented to a charger and power control system which is applicable to home appliances or notebook PC directly. The charger and power control system is controlled by a microprocessor, M50927 (Mitzubishi), to improve cost to performance ratio. The charger algorithm is designed to be operated under optimal charge node and various protections are added tn improve the reliability of the charger.

• Journal of Korean Association for Spatial Structures
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• v.18 no.4
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• pp.89-96
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• 2018

The paper presents the damage estimation of bridge structures in Daegu city based on the scenario-based earthquakes. Since the fragility curves for domestic bridge strucures are limited, the Hazus methodology is employed to derive the fragility curves and estimate the damage. A total of four earthuquake scenarios near Daegu city are assumed and structure damage is investigated for 81 bridge structures. The seismic fragility function and damage level of each bridge had adopted from the analytical method in HAZUS and then, the damage probability using seismic fragility function for each bridge was evaluated. It was concluded that the seismic damage to bridges was higher when the magnitude of the earthquake was large or nearer to the epicenter.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2000.05a
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• pp.18-18
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• 2000

• 한국전기화학회:학술대회논문집
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• 2001.04a
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• pp.5-5
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• 2001

• Asian Journal of Innovation and Policy
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• v.7 no.1
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• pp.1-8
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• 2018