• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.371-374
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• 2005

This paper presents the design and fabrication of a cost effective and broad band 8$\times$8 stacked patch array antenna which are backed by a metal cavity operating at 400Hz based on 4 layers LTCC technology. Gain of antenna can be enhanced by using a metal cavity, which can be easily implemented by using LTCC substrates and vias. The broadband performance can be obtained by varying the dimension of patch and the number of layers. Furthermore, to keep the feeding network as smal1 as possible and reduce radiation from feeding network a mirrored patch orientation and embedded micro strip line are adopted, The fabricated antenna is $40\times45\times0.4$ $mm^3$in size. It shows gain 20.4dBi, beam width 10.7deg and impedance bandwidth of l0dE return loss 3.35GHz (40.9$\sim$44.25 GHz), which is about 8% of a center frequency.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.8
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• pp.739-745
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• 2009

This paper presents a design for trapezoidal planar UWB(Ultra Wide-band) antenna using symmetry meander line to realize broad bandwidth at low frequency region. The size of proposed design antenna is $15.5{\times}21{\times}1.6mm^3$ and dielectric substrate considered in design has 4.4 of relative permittivity. The calculated bandwidth is from 1.31 GHz to 10.83 GHz and the measured return loss is 1.5 GHz to 10.6 GHz at -10 dB below, and satisfies with the UWB antenna's bandwidth. The simulated and measured radiation patterns show fine agreement with each other at each frequency.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.4
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• pp.258-265
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• 2003

This paper suggests the noise reduction method of the engine cooling fan. The fan noise contribution to the OASPL of engine room was estimated and the noise source was identified for the rotating fan by sound intensity method. And the program for Predicting the noise spectrum of axial flow fan was also developed. The radiated acoustic pressure is expressed in terms of discrete frequency noise Peaks at BPF and its harmonics and the line spectrum at the broad band by the proposed noise generation mechanisms. In this Paper, it Is shown that the comparison of the measured and calculated noise spectra of fan validates the noise predicting program. And this paper presents the characteristics of the fan noise in order to modify the design parameters. Accordingly, the design parameters were determined for the noise reduction of the fan.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.5
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• pp.509-515
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• 2009

This paper proposes an optimal design scheme to reduce the noise of the engine cooling fan by adapting Kriging with two meta-heuristic techniques. An engineering model has been developed for the prediction of the noise spectrum of the engine cooling fan. The noise of the fan is expressed as the discrete frequency noise peaks at the BPF and its harmonics and line spectrum at the broad band by noise generation mechanisms. The object of this paper is to find the optimal design for noise reduction of the engine cooling fan. We firstly show a comparison of the measured and calculated noise spectra of the fan for the validation of the noise prediction program. Orthogonal array is applied as design of experiments because it is suitable for Kriging. With these simulated data, we can estimate a correlation parameter of Kriging by solving the nonlinear problem with genetic algorithm and find an optimal level for the noise reduction of the cooling fan by optimizing Kriging estimates with simulated annealing. We notice that this optimal design scheme gives noticeable results. Therefore, an optimal design for the cooling fan is proposed by reducing the noise of its system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1307-1312
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• 2007

This paper proposes an optimal design scheme to reduce the noise of the engine cooling fan by adapting Kriging with two meta-heuristic techniques. An engineering model has been developed for the prediction of the noise spectrum of the engine cooling fan. The noise of the fan is expressed as the discrete frequency noise peaks at the BPF and its harmonics and line spectrum at the broad band by noise generation mechanisms. The object of this paper is to find the Optimal Design for Noise Reduction of the Engine Cooling Fan. We firstly show a comparison of the measured and calculated noise spectra of the fan for the validation of the noise prediction program. Orthogonal array is applied as design of experiments because it is suitable for Kriging. With these simulated data, we can estimate a correlation parameter of Kriging by solving the nonlinear problem with genetic algorithm and find an optimal level for the noise reduction of the cooling fan by optimizing Kriging estimates with simulated annealing. We notice that this optimal design scheme gives noticeable results. Therefore, an optimal design for the cooling fan is proposed by reducing the noise of its system.

• Conservation Science in Museum
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• v.13
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• pp.33-36
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• 2012

Analysis of Flat board-shaped Lacquer ware excavated from Daho-ri was conducted. The result of species identification is identifed as Pinus spp. As a result of microscopic observation, lacquer fragment is consist of 5 layers and its thickness is about 100 ㎛. Infrared spectroscopy of the lacquer ware revealed that they had a very similar absorption band as refined lacquer, confirming that they were painted with lacquer. Result of Analysis for Circular metal ornament is alloy smelted by tin and lead. It is called Pewter. While The species of wooden objects investigated until now is broad-leaved tree; the species of flat board-shaped lacquer ware is conifer.

• Korean Journal of Ichthyology
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• v.6 no.1
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• pp.21-27
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• 1994

The Damselfish, Chromis fumea, was originally described by Tanaka(1917) from Nagasaki, Japan. In the Korean waters, 27 specimens of Chromis fumea(Tanaka) were collected from Cheju-do, on April-August, 1993, and described herewith as new to the Korean fish fauna. Chromis fumea differs from Chromis notatus in having serrate preopercle, no distinctive black spot in pectoral base and caudal fin with a broad blackish band in each lobe. Yeonrnoo-ja-ri-dom is proposed as Korean name of Chromis fumea.

• The Transactions of the Korean Institute of Power Electronics
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• v.20 no.2
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• pp.137-143
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• 2015

This paper presents the intra capacitance modeling based on the winding method and section bobbin for CM choke capable of EMI attenuation of broad bands from lower to higher frequency bands and high frequency type common-mode choke capable of EMI attenuation of high frequency band used in the EMI Block of LED-TV SMPS. The case of high frequency type CM choke can be explained by the parasitic capacitance of three types of CM choke. The winding method of section bobbin type is smaller than the others. The first resonant frequency of the proposed CM choke tends to increase as the parasitic capacitance becomes small and its impedance characteristics improved performance as the first resonant frequency increases. The CM chokes of the proposed section bobbin type shows that in the future, the method may have practical use in LED/LCD-TV SMPS and in several applications, such as LED lighting, adapters, and so on.

• Animal Systematics, Evolution and Diversity
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• v.36 no.2
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• pp.123-127
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• 2020

This paper reports four species of Erebidae from the southern part of Korea: two Boletobiinae, Honeyania ragusana (Freyer, 1845), Enispa masuii Sugi, 1982, one Hermininae, Adrapsa ablualis Walker, 1859, and one Arctiinae, Stictane rectilinea (Snellen, 1879). Honeyania ragusana can be distinguished by the following: a blackish dot on the apex of the forewing with strongly curved medial lines, a long slender uncus and a strongly distally bifurcated valva with a large distally expanded costa and a thumb-shaped process of sacculus on the male genitalia as well as a sclerotized antrum, strongly tapered ductus bursae, and large corpus bursae on the female genitalia. Enispa masuii, a lichen feeder, can be distinguished by the whitish medial lines of the grayish fore- and hindwings, and a pair of rounded ball-shaped lamella antevaginalis, long, sclerotized ductus bursae, and pear-shaped corpus bursae without signum of the female genitalia. Adrapsa ablualis can be distinguished by the whitish medial lines of the fore- and hindwings and large medial process of the costa and dentate distal margin of the valva of the male genitalia. Stictane rectilinea can be distinguished by the broad dark grayish medial band of the forewing and the long knife-shaped valva with a strongly hooked process on the distal part of the sacculus of the male genitalia.

• Journal of Powder Materials
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• v.15 no.3
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• pp.210-213
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• 2008

Elongated CdSe nanoparticles with a diameter of 3-7nm have been successfully synthesized using two surfactants of trioctylphospine (TOP) and hexadecylamine (HDA) at $160^{\circ}C$. The formation of elongated CdSe nanoparticles is possibly due to the cooperative effects from both the different binding capability of two surfactants (TOP and HDA) and intrinsically anisotropic crystal structure of the CdSe. The electron diffraction pattern of CdSe nanoparticles revealed the formation of wurzite phase. The CdSe samples showed red-shifted wavelength from 560 to 580nm with increasing the refluxing time due to the gradual growth of CdSe nanoparticles. The relatively broad absorption band can be attributed to the surface state of CdSe nanoparticles. The possible formation mechanism of elongated CdSe nanoparticles was proposed and the characteristics of CdSe have been discussed as well.