• 대한전자공학회논문지TC
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• 제38권4호
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• pp.27-37
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• 2001

광대역과 고이득과 낮은 교차 편파 레벨을 가지는 H자 모양의 개구면을 가진 스트립 급전된 패치 안테나를 설계 및 제작하고 정재파비, 스미스챠트 임피던스 특성, 동일/교차 편파 방사패턴, 이득 등을 측정하였다. 본 안테나의 측정된 대역폭(VSWR<2.0)은 47.1%이다. 또한 후방방사를 줄이고 이득을 높이기 위해 반사판을 사용하였을 때 교차 편파 레벨은 E-plane에서 -18.2 dB이하이고 H plane에서 -25.7 dB이하이다. 그리고 최대 이득은 2.05 GHz의 주파수에서 10.4 dB이며, 3 dB gain 대역폭은 중심주파수 2.17 GHz에서 24%의 광대역폭을 가짐을 알 수 있었다. 본 안테나는 광대역을 필요로 하는 이동통신, 무선 LAN, RF 통신시스템 등에 사용될 수 있다.

• 대한수학회보
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• 제49권5호
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• pp.1089-1099
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• 2012

We construct three kinds of complete embedded singly-periodic minimal surfaces in $\mathbb{H}^2{\times}\mathbb{R}$. The first one is a 1-parameter family of minimal surfaces which is asymptotic to a horizontal plane and a vertical plane; the second one is a 2-parameter family of minimal surfaces which has a fundamental piece of finite total curvature and is asymptotic to a finite number of vertical planes; the last one is a 2-parameter family of minimal surfaces which fill $\mathbb{H}^2{\times}\mathbb{R}$ by finite Scherk's towers.

• 호남수학학술지
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• 제31권4호
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• pp.633-637
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• 2009

We prove using the Szeg$\H{o}$ kernel and the Garabedian kernel that a Toeplitz operator on the boundary of $C^{\infty}$ smoothly bounded domain associated to a smooth symbol vanishes only when the symbol vanishes identically. This gives a generalization of previous results on the unit disk to more general domains in the plane.

• JSTS:Journal of Semiconductor Technology and Science
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• 제14권5호
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• pp.557-565
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• 2014

We report the effect of basal-plane stacking faults (BSFs) on X-ray diffraction (XRD) of non-polar (11$\underline{2}$0) a-plane GaN films with different $SiN_x$ interlayers. Complete $SiN_x$ coverage and increased three-dimensional (3D) to two-dimensional (2D) transition stages substantially reduce BSF density. It was revealed that the Si-doping profile in the Si-doped GaN layer was unaffected by the introduction of a $SiN_x$ interlayer. The smallest in-plane anisotropy of the (11$\underline{2}$0) XRD ${\omega}$-scan widths was found in the sample with multiple $SiN_x$ layers, and this finding can be attributed to the relatively isotropic GaN mosaic resulting from the increase in the 3D-2D growth step. Williamson-Hall (WH) analysis of the (h0$\underline{h}$0) series of diffractions was employed to determine the c-axis lateral coherence length (LCL) and to estimate the mosaic tilt. The c-axis LCLs obtained from WH analyses of the present study's representative a-plane GaN samples were well correlated with the BSF-related results from both the off-axis XRD ${\omega}$-scan and transmission electron microscopy (TEM). Based on WH and TEM analyses, the trends in BSF densities were very similar, even though the BSF densities extracted from LCLs indicated that the values were reduced by a factor of about twenty.

• 제어로봇시스템학회논문지
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• 제21권11호
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• pp.1050-1056
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• 2015

In this paper, we use the characteristics of electromagnetic waves underwater attenuation for estimating linear distance between a transmitting node and receiving node, and research underwater vertical plane attenuation model for constructing the underwater localization system. The underwater localization of 2 dimensional with the plane attenuation model in the horizontal plane (H-plane) was proposed previous research. But for the 3 dimensional underwater localization, the additional vertical plane (E-plane) model should be considered. Because the horizontal plane of omnidirectional antenna has the same attenuation tendency in x-y plane according to the distance, whereas in vertical plane shows an irregular pattern in x-z plane. For that reason, in the vertical plane environment, the attenuation should be changed by the position and inclination. Hence, in this paper the distance and angle between transmitting and receiving node are defined using spherical coordinate system and derive an antenna gain pattern using half power beam width (HPBW). The HPBW is called a term which defines antenna's performance between isotropic and other antennas. This paper derives omnidirectional antenna's maximum gain and attenuation pattern model and define vertical plane's gain pattern model using HPBW. Finally, experimental verifications for the proposed underwater vertical plane's attenuation model was executed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계 학술대회논문집(수송기계편)
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• pp.170-173
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• 2005

The objective of this paper is to perform measurements of power transmission and reflection coefficients in a coupled plate. The coupled plate has been divided into 2 subsystems. The out-of-plane vibration has been only considered with assumption of relatively small in-plane vibration. The coupling loss factors have been measured with consideration of the power balance condition. The power transmission and reflection coefficients has been estimated from the measured values of the coupling loss factors. The measured power transmission and reflection coefficients have been compared with the corresponding theoretical coefficients in a semi-infinite coupled plate.

• 천문학회보
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• 제36권2호
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• pp.118-118
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• 2011

We executed a simultaneous survey of 22 GHz water maser and 44 GHz methanol maser toward 290 shocked $H_2$ emitting regions, which were identified from the galactic plane survey at $H_2$ 2.122 micrometer (UKIRT Widefield Infrared Survey for $H_2$; UWISH2). The primary goal of this observation is to characterize the H2 emission sources whether they are sincerely due to the outflows of young stellar objects or other shocked emission from older/evolved objects. We discovered 15 water maser sources and 15 methanol maser sources which provide the detection rate of around 5 percents. Most of detected sources have IRAS sources, infrared dark clouds, and/or submilimeter sources in the beam size of KVN single dish. In this poster, we will present the detailed results of our survey observation and discuss about the star formation rate in the galactic plane.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.703-704
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• 2007

Most of the transmission lines in Korea pass through a mountains. The forest fire occurred in around the transmission lines make an accident such as flashover and faults in the power transmission lines. In spite of that risk, there are no research on the flashover characteristics by fires in electric discharge engineering in our country. This paper was mentioned about the relation between the flame and flashover characteristics. We were carried out simple test by using artificial flame generator and rod-plane or conductor-plane gaps. And we were summarized test results.

• 대한수학회논문집
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• 제37권1호
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• pp.125-136
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• 2022

For k = 1, 2, let $f_k=h_k+{\bar{g_k}}$ be normalized harmonic right half-plane or vertical strip mappings. We consider the convex combination ${\hat{f}}={\eta}f_1+(1-{\eta})f_2={\eta}h_1+(1-{\eta})h_2+{\overline{\bar{\eta}g_1+(1-\bar{\eta})g_2}}$ and the combination ${\tilde{f}}={\eta}h_1+(1-{\eta})h_2+{\overline{{\eta}g_1+(1-{\eta})g_2}}$. For real 𝜂, the two mappings ${\hat{f}}$ and ${\tilde{f}}$ are the same. We investigate the univalence and directional convexity of ${\hat{f}}$ and ${\tilde{f}}$ for 𝜂 ∈ ℂ. Some sufficient conditions are found for convexity of the combination ${\tilde{f}}$.

• Journal of Magnetics
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• 제2권3호
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• pp.101-104
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• 1997

Vector Moving Preisach model has been applied to the unoriented Co-based alloy thin film media. In the model, the out-of plane easy axis distribution of the particles was derived directly from the texture coefficient phkl obtained from XRD analysis, which corresponds to the fraction of the grains that have the {hkl} plane lying parallel to in-plane direction. The model was validated, by its prediction of a variety of responses, including major loop, minor loop, and the angular dependence of coercivities.