• Nuclear Engineering and Technology
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• 제52권4호
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• pp.700-707
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• 2020

This study is concerned with the investigation of the half-space albedo problem for "İnönü-linear-quadratic anisotropic scattering" by the usage of Modified FN method. The method is based on Case's method. Therefore, Case's eigenfunctions and its orthogonality properties are derived for anisotropic scattering of interest. Albedo values are calculated for various linear, quadratic and İnönü anisotropic scattering coefficients and tabulated in Tables.

• Nuclear Engineering and Technology
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• 제55권1호
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• pp.324-329
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• 2023

Different types of deterministic solution methods were used to solve neutron transport equations corresponding to half-space and slab albedo problems. In these types of solution methods, in addition to the error of the numerical solutions, the obtained results contain truncation and discretization errors. In the present work, a non-analog Monte Carlo method is provided to simulate the half-space and slab albedo problems with Inönü and Anlı-Güngör strongly anisotropic scattering functions. For each scattering function, the sampling method of the direction of the scattered neutrons is presented. The effects of different beams with different angular dependencies and the effects of different scattering parameters on the reflection probability are investigated using the developed Monte Carlo method. The validity of the Monte Carlo method is also confirmed through the comparison with the published data.

• Journal of electromagnetic engineering and science
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• 제13권1호
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• pp.16-21
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• 2013

This study presents the angular effects of virtual vertices inserted for effective treatment of the boundary edge laid on an infinite conducting surface in a half-space scattering problem. We investigated the angular effects of virtual vertices by first computing the radar cross section (RCS) of a specific scatterer; i.e., a tilted conducting plate in contact with the ground surface, by inserting the virtual vertex in half-space. Here, the electric field integral equation is used to solve this problem with various virtual vertex angles (${\theta}_{\nu}$) and conducting plate inclination angles (${\theta}_r$) ranging from $0^{\circ}$ to $180^{\circ}$. The effects of the angles ${\theta}_{\nu}$ and ${\theta}_r$ on the RCS computation are clearly shown with numerical results with and without the virtual vertices in free- and half-spaces.

• 비파괴검사학회지
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• 제31권6호
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• pp.650-655
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• 2011

Analysis of two-dimensional Rayleigh wave scattering pattern by a surface defect is studied through modified boundary element method. BEM proposed in this paper has special treatment at each end of boundary which should have the Rayleigh wave go away without any generation of virtual reflections. It is shown that treatment for truncated boundary which is used to model two-dimensional Rayleigh waves' behavior in an elastic half-space is successfully implemented. To check numerical results' accuracy, time domain IFFT signal of the displacements is presented. Improvement on getting rid of unwanted influence of truncated boundary induced by 2-D Rayleigh waves on a flat surface of an elastic half-infinite medium is shown. As a final goal, the numerical results of Rayleigh wave scattering trend are plotted and they are compared with theoretical curves to prove its accuracy.

• 한국전자파학회논문지
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• 제14권8호
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• pp.803-808
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• 2003

손실 반공간에 두 개의 원통형 파이프가 묻혀 있는 경우 파이프와 주변 매질의 특성을 반복 기법 최적화 역산란을 적용하여 구했다. 산란 전계는 경계요소법을 이용하여 계산하였으며 파이프의 크기, 위치, 내부매질의 비유전을, 도전을, 주변 매질의 비유전을, 도전을 등의 파라미터는 측정 산란 전계로부터 유전 알고리즘과 Levenberg-Marquardt 알고리즘의 혼합 알고리즘을 이용하여 역으로 계산하였다. 두 파이프가 거의 근접해 있는 경우도 역산란이 가능함을 보였다. 산란 전계의 측정오차에 의한 illposednes 는 파수 영역에서 지수 함수적으로 감쇄하는 감쇄모드를 제거하여 안정화시켰다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2000년도 제18회 학술발표회 논문개요집
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• pp.118-118
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• 2000

We investigate Frohlich-like electron--optical-phonon interactionsin uniaxial crytals based on the macroscopic dielectric continuum model. In general, the optical-phonon branches support mixed longitudinal and transverse modes due to the anisotropy. For heterostructures with double interfaces and superlattices, it is known that confined, interface, and half-space optical phonon modes exist in zincblende cystals. In uniaxial structures, additional propagating modes may exist in wurtzite heterosystems due to anisotropic phonon dispersion. This is especially the case when the dielectric properties of the adjacent heterostructure materials do not differ substantially. The dispersion relations and the interaction Hamiltonians for each of these modes are derived.

• 한국지반공학회지:지반
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• 제5권3호
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• pp.5-18
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• 1989

본 연구에서는 구조물의 내진해석에 사용되는 입력운동을 1차원 파전파이론, Elsabee-Morray의 이론, 유한 요소이론을 이용하여 산출하여 상호비교 검토하였고 산정된 입력운동을 이용해서 구조 물의 응답을 유한요소 해석과 반무한체 해석을 이용하여 산정해서 역시 비교 검토하였다. 지반의 강성증가에 따른 입력운동과 구조물 응답의 변화를 고찰하기 위하여 Parametric Study를 수행하였으며 산출된 여러 이론들에 따른 구조물 응답결과를 내진규준에 따라서 산출된 구조물 응답과 비교하였다. 해석 결과는 Scattering Field 효과를 고려하지 않은채 산출된 입력운동이 Scattering Field 효과를 고려하여 얻어진 입력운동보다 약 2배 정도 크게 산출되어 결과적으로 입력운동의 차이에 따른 구조물응답이 상당한 차이를 보여 내진 설계시 이 효과를 무시할 수 없을 정도로 큼을 알 수 있었다.

• 한국전자파학회논문지
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• 제25권11호
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• pp.1113-1120
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• 2014

본 논문에서는 무한 평판에 위치한, 파장에 비하여 작은 개구의 투과효율을 향상시키는 두 가지 방법으로서 첫째, 리지가 있는 소형 원형 개구와 같은 투과공진개구 구조를 이용하는 방법, 둘째, 투과공진기 구조를 이용하는 일반적인 방법을 생각해 보았다. 특히 상기 두 가지 구조의 경우, 최대 투과 단면적이 공통적으로 $\frac{2G{\lambda}^2}{4{\pi}}[m^2]$(G는 개구의 이득)이 됨을 보였다. 그리고 두 구조의 근접장 현미경의 탐침 구조에의 적용 가능성을 검증하기 위하여 구형 도파관의 종단면에 장착된 구조로서 임피던스 정합 특성을 조사하였다. 또한, 상보적인 문제로서 파장에 비하여 충분히 작은 공진 산란체의 경우에도 관찰되는, 앞서 다룬 투과 공진 현상과 본질적으로 유사한 산란 공진 현상에 대하여도 논의하였다. 이러한 논의는 원자 물리 분야에서 원자 구조의 산란 단면적이 실제 원자 구조의 물리적인 단면적에 비하여 매우 큰 현상에 대한 이해를 하는데 도움이 될 것으로 사료된다.

• 천문학회지
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• 제56권1호
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• pp.23-33
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• 2023

We investigate the diffusion process of Thomson-scattered line photons in both real space and frequency space through a Monte Carlo approach. The emission source is assumed to be monochromatic and point-like embedded at the center of a free electron region in the form of a sphere and a slab. In the case of a spherical region, the line profiles emergent at a location of Thomson optical depth τ_Th from the source exhibit the full width of the half maximum σ_λ ≃ τ^1.5_Th. In the slab case, we focus on the polarization behavior where the polarization direction flips from the normal direction of the slab to the parallel as the slab optical depth τ_Th increases from τ_Th ≪ 1 to τ_Th ≫ 1. We propose that the polarization flip to the parallel direction to the slab surface in optically thick slabs is attributed to the robustness of the Stokes parameter Q along the vertical axis with respect to the observer's line of sight whereas randomization dominates the remaining region as τ_Th increases. A brief discussion on the importance of our study is presented.

• 조명전기설비학회논문지
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• 제25권12호
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• pp.113-118
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• 2011

In this study, investigation and appraisal method for the scene of a fire according to electrical fire hazards of hair dryer which is usually used at living space are presented. Hair dryer is briefly composed of heating part, wind part and control part. Electrical fire hazards of hair dryer are insulation destruction of power cord, ignition by overheat of heating coil, scattering spark on inside dust, overheat of motor by fan shackle, ignition by carelessness of user, and so on. Fire cause by hair dryer can be perceived through investigation about half-disconnection of power cord, contact badness of power plug, verification of heating coil, fan and switch. These results are expected to be utilized effectively in a countermeasure to prevent an electrical fire by hair dryer.