• 한국세라믹학회지
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• 제33권3호
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• pp.313-320
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• 1996

We have fabricated an in-plane aligned a-axis oriented YBa2Cu3O7-x (a-YBCO) thin film on a LaSrGaO4(100) substrate with a PrBa2Cu3O7-x(PBCO) template layer by two step plused laser deposition using 308 nm XeCl excimer laser. A YBCO layer and PBCO layer grown at low temperatures were used as template layers. We have investigated the effect of the deposition temperature of template layers on the superconducting and struc-tural properties of in-plane aligned a-YBCO thin films. An optimal deposition temperature of the PBCO template layers was 630. In-plane aligned a-YBCO thin films showed an anisotropy ratio in resistivity of 11.5 and a zero resistance temperature of 88 K.

• 전자공학회논문지D
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• 제35D권1호
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• pp.16-26
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• 1998

This paper presents a design methodology for magnetically tunable X-band E-plane type waveguide filters. The proposed design is based on using of quarter wavelength transmission line for compensating the negative length transmission line of end K-inverters of E-plane type waveguide filters. The derived formulae are applied for initial design and the correction method is also provided for final design by considering the frequency dependent characteristic of K-inverters. The analysis results of E-plane pype waveguide structure loaded with ferrite slab are obtained using the edge based finite element method including higher order mode effecets. It is shown that the unilateral finline E-plane type waveguide filter as well as the bilateral finline E-plane type waveguide filter achieves the the manetically tunable characteristic. The X-band experimantal results for bilateral and unilateral finline E-plane type waveguide filters agree well with the simulated data.

• International Journal of Naval Architecture and Ocean Engineering
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• 제12권1호
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• pp.843-855
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• 2020

X-plane submarines show better maneuverability as they have much longer span of control plane than that of cross plane submarines. In this study, captive model tests were conducted to evaluate the maneuverability of an X-plane submarine using Computational Fluid Dynamics (CFD) and a mathematical maneuvering model. For CFD analysis, SNUFOAM, CFD software specialized in naval hydrodynamics based on the open-source toolkit, OpenFOAM, was applied. A generic submarine Joubert BB2 was selected as a test model, which was modified by Maritime Research Institute Netherlands (MARIN). Captive model tests including propeller open water, resistance, self-propulsion, static drift, horizontal planar motion mechanism and vertical planar motion mechanism tests were carried out to obtain maneuvering coefficients of the submarine. Maneuvering simulations for turning circle tests were performed using the maneuvering coefficients obtained from the captive model tests. The simulated trajectory showed good agreement with that of free running model tests. From the results, it was proved that CFD simulations can be applicable to obtain reliable maneuvering coefficients for X-plane submarines.

• 한국강구조학회 논문집
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• 제19권1호
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• pp.129-137
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• 2007

본 연구에서는 X-브레이싱 접합부의 경계조건에 따른 탄성 면외 좌굴하중 및 유효 좌굴길이 계수에 관한 연구를 수행하였다. X-브레이싱의 접합부는 연결방법에 따라 강접합 혹은 단순 연결로 가정할 수 있으며, 이러한 접합부의 경계 조건은 X-브레이싱의 좌굴하중에 영향을 미친다. 본 연구에서는 접합부의 경계 조건에 따른 X-브레이싱의 면외 유효 좌굴길이 계수들을 유도 하였으며, 면외 유효 좌굴계수들은 압축부재와 인장부재의 길이비 $L_P$/$L_T$, 인장력과 압축력의 비 T/P, 및 인장부재와 압축부재의 Euler 좌굴하중의 비 $P_{ET}$/$P_{EP}$의 함수로 나타났다. 이러한 연구결과는 기존 연구자들 및 유한요소해석결과와 비교 분석하여 그 타당성과 적용성을 검증하였다. 마지막으로 유도된 면외 유효 좌굴길이 계수들을 비교하여 접합부의 경계 조건이 X-브레이싱의 면외 좌굴하중에 미치는 영향을 분석하였다.

• 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.

• 한국항공우주학회지
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• 제49권6호
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• pp.465-472
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• 2021

고정익 모선과 자선의 공중에서의 분리-재결합 상황에 대한 실제 비행시험 이전에 시뮬레이션을 통해 자선의 비행제어 시스템을 검증할 필요가 있다. 본 논문에서는 X-Plane의 후류 기능을 기반으로 연구실 환경에서 자선의 비행제어 시스템 개발을 위한 시뮬레이션 환경을 구축하였다. 이를 위해 자선의 공력해석을 수행하고 Simulink를 사용하여 항공기를 모사하였으며, X-Plane을 활용하여 시각화와 바람, 돌풍, 모선의 이동을 구현하였다. 유도제어 알고리즘을 Simulink 내 자선 모델에 적용하여 모의 근접비행을 수행함으로써 구축된 시뮬레이션 환경을 검증하였다. 또한 비행 결과를 통해 자선이 모선 후방에서 안전하게 비행할 수 있는 영역을 확인하였다.

• 대한수학회논문집
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• 제9권2호
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• pp.327-329
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• 1994

The Dirichlet problem (DP) on the upper half plane {z = x ＋ iy : y > 0} is to find a real-valued harmonic function u(x, y) satisfying u(x, 0) = g(x) almost everywhere for some reasonably nice function g defined on the real line, which is called the data on the boundary for (DP).(omitted)

• 대한수학회지
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• 제33권4호
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• pp.1009-1038
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• 1996

R.L. Bishop and S.I. Goldberg [3] introduced the notion of totally real bisectional curvature B(X, Y) on a Kaehler manifold M. It is determined by a totally real plane [X, Y] and its image [JX, JY] by the complex structure J. where [X, Y] denotes the plane spanned by linealy independent vector fields X, and Y. Moreover the above two planes [X, Y] and [JX, JY] are orthogonal to each other. And it is known that two orthonormal vectors X and Y span a totally real plane if and only if X, Y and JY are orthonormal.

• 제어로봇시스템학회논문지
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• 제19권5호
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• pp.442-449
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• 2013

In this paper, a simulation system based on X-Plane and MATLAB/Simulink for multiple UAVs is presented. For the conceptual design of this proposed system, a hierarchical system architecture for multiple UAVs is presented. This architecture has object-oriented data structure which consists of three objects (UAV status, mission and task, and environment) and a hierarchy consisting of four layers (decision making layer, task assignment layer, path and motion planning layer, and collision avoidance layer) is also proposed. In addition, this paper shows a implementation of simulation system based on the proposed system architecture using X-Plane and MATLAB/Simulink. The result of simulation from the developed system in this paper validate capability of application for multiple UAVs in real environment.

• 한국세라믹학회지
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• 제13권4호
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• pp.5-8
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• 1976

Both oriented and non-oriented ferroxplana $Co_{1-x}Zn_xZ(Ba_3Co_{2(1-x)}Zn_{2x} Fe_{24}O_{41})$ with x=0.00, 0.45 were prepared by conventional ceramic method. The magnetostrictions of thus prepared specimens were measured by use of the three terminal capacitor device at room temperature. The magnitude of measured values was approximately five times greater than that of ZnY ferroxplana. The easy-magnetization plane at room temperature of both CoZ and Co0.55 $Zn_{0.45}$Z was their basal plane. The magentostrictions in the basal plane and the other planes showed saturated values at magnetic field intensity of about 2Koe and 4Koe, respectively. The magnetostriction constants $K_1, \; K_2, \;K_3\; and\; K_4$ for CoZ were -2.4, -10.5, -5.9 and -45.2$\times10^{-6}$ , while those for $Co_{0.55}Zn_{0.45}Z$ were +0.1, -1.2, -6.3 and -39.0$\times$10^{-6}, , respectively.