• 한국광학회지
• /
• 제31권6호
• /
• pp.268-273
• /
• 2020

레이저 빔이 산란 매질에서 반사될 때 발생하는 스펙클 패턴을 모니터링함으로써 산란 매질에 입사하는 레이저 빔들의 결맞는(coherent) 결합 상태를 분석하고자 하였다. 이를 위하여 가간섭성이 높은 3개의 시준 레이저 광원을 자유공간에서 렌즈를 이용하여 무작위 표면특성을 가진 산란목표물(scattering target)에 집속한 후, 되돌아오는 빔의 스펙클 패턴을 푸리에 영역에서 살펴보았다. 목표물에 입사하는 단일 레이저 빔의 크기변화 및 3개 결맞는 레이저 빔 간의 공간적인 빔결합 정도에 따라 스펙클 패턴의 평균적인 크기가 변하게 되는데, 이를 푸리에 영역에서 분석함으로써 결맞음 빔결합의 효율을 판별할 수 있는 단일 모니터링 변수를 도출할 수 있었다.

• 문화기술의 융합
• /
• 제9권3호
• /
• pp.619-624
• /
• 2023

본 논문에서는 2중 유전체층 사이의 저항띠 격자구조에 의한 TE(transverse electric) 산란 문제를 전자파 수치해석 방법으로 알려진 FGMM(fourier galerkin moment method)를 이용하여 해석하였다. 경계조건들은 미지의 계수를 구하기 위하여 이용하였고, 산란 전자계는 Floquet 모드 함수의 급수로 전개하였고, 저항띠의 해석을 위해 저항 경계조건을 적용하였다. 2중 유전체층의 문제를 취급하기 위하여 유전체층들의 두께와 비유전율을 동일한 값을 가지는 경우에 대해서만 수치계산하였다. 전반적으로, 저항띠 균일 저항율이 증가하면 저항띠에 유도되는 전류밀도는 감소하였고 반사 전력은 감소하였으며, 상대적으로 투과전력은 증가하였다. 본 논문에서 제안된 구조에 대한 수치결과들은 기존 논문의 수치해석 방법인 PMM의 결과들과 비교하여 매우 잘 일치하였다.

• 문화기술의 융합
• /
• 제9권3호
• /
• pp.641-646
• /
• 2023

본 논문에서는 2중 유전체층 사이의 저항띠 격자구조에 의한 TM(transverse magnetic) 산란 문제를 전자파 수치해석 방법으로 알려진 FGMM(fourier galerkin moment method)를 이용하여 해석하였다. 경계조건들은 미지의 계수를 구하기 위하여 이용하였고, 산란 전자계는 Floquet 모드 함수의 급수로 전개하였고, 저항띠의 해석을 위해 저항 경계조건을 적용하였다. 전반적으로, 저항띠의 균일저항율이 증가하면 저항띠에 유도되는 전류밀도의 크기는 감소하였고 반사 전력은 감소하였으며, 상대적으로 투과전력은 증가하였다. 또한 유전체 층의 두께가 증가할수록 반사전력은 증가하였고 상대적으로 투과전력은 상대적으로 감소하였다. 본 논문에서 제안된 구조에 대한 수치결과들은 기존 논문의 수치해석 방법인 PMM의 결과들과 비교하여 매우 잘 일치하였다.

• Bulletin of the Korean Chemical Society
• /
• 제33권2호
• /
• pp.553-558
• /
• 2012

A simple new method was developed for the determination of betaine in Fructus Lycii using hydrophilic interaction liquid chromatography with evaporative light scattering detection (HILIC-ELSD). Good chromatographic separation and reasonable betaine retention was achieved on a Kinetex HILIC column ($2.1{\times}100mm$, $2.6{\mu}m$) packed with fused-core particle. The mobile phase consisted of (A) acetonitrile and (B) 10 mM ammonium formate (pH 3.0)/acetonitrile (90/10, v/v). It was used with gradient elution at a flow rate of 0.7 mL/min. The column temperature was set at $27.5^{\circ}C$ and the injection volume was $10{\mu}L$. The ELSD drift tube temperature was $50^{\circ}C$ and the nebulizing gas (nitrogen) pressure was 3.0 bar. Stachydrine, a zwitterionic compound, was used as an internal standard. Calibration curve over $10-250{\mu}g/mL$ showed good linearity ($R^2$ > 0.9992) and betaine in the 70% methanol extract of Fructus Lycii was well separated from other peaks. Intraand inter-day precision ranged from 1.1 to 3.0% and from 2.4 to 5.3%, respectively, while intra- and inter-day accuracy ranged from 100.0 to 107.0% and from 94.3 to 103.9%, respectively. The limit of quantification (LOQ) was $10{\mu}g/mL$ and the recoveries were in the range of 98.2-102.7%. The developed HILIC-ELSD method was successfully applied to quantitatively determine the amount of betaine in fourteen Fructus Lycii samples from different locations, demonstrating that this method is simple, rapid, and suitable for the quality control of Fructus Lycii.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2009년도 추계학술대회 논문집
• /
• pp.251-251
• /
• 2009

The generation of energy and the cooling of system using thermoelectric semiconductor material have been in spotlight. Thermoelectric effect increases with the decrease of the thermal conductivity. In the thermoelectric devices, thermal conductivity is related to phonon scattering. Therefore, few studies have been conducted in the thermoelectric materials dispersed nano oxide particle for increasing the phonon scattering. However, core-shell structure which nano particle disperses in solvents and then which thermoelectric materials coated on the nano oxide particles has not been reported. In this study, we selected commercial nano powder such as $Al_2O_3$. This nano particle was about 20nm and was crushed aggregate by mechanical treatment. We have developed the effect of the dispersant and the solvent. The properties of particles were evaluated by SEM, TEM, particle size analysis, and BET. Dispersion and dispersion stability were evaluated by electronic microscope and turbidity.

• 전자공학회논문지A
• /
• 제29A권11호
• /
• pp.19-24
• /
• 1992

In this paper, a high frequency method is developed which combines the uniform Geometrical Theory of Diffraction(GTD) and the Aperture Integration(AI) to analyze electromagnetic plane wave scattering by a perfectly-conducting, open-ended, semi-infinite parallel plate waveguide with a uniform layer of absorbing material on its inner wall, and with a slanted planar termination inside. In this method, first, the field of an arbitary point inside the paraller plate waveguide is computed by the GTD. Second, the field scattered into exterior region by the waveguide is found using the equivalent current, which can be obtaind from the aperture field of the waveguide and using the AI. Numerical results based on this GTD method are presented and compared with those based on the mode matching method.

• 전자공학회논문지A
• /
• 제32A권11호
• /
• pp.1-7
• /
• 1995

The problem of amplitude-and frequency-modulated waveforms is analyzed when a linearly polarized electromagnetic wave is scattered by a slowly rotating rotor with metal plates. ECM in conjunction with a quasi-stationary method is used to analyze the modulated waveforms. The modulated waveforms depend on the orientation and dimension of the object. its rotation speed, and very strongly on the incident and scattering directions. The modulate waveforms of a rotating non-skewed metal plate and a rotor with two blades are functions of twice the rotating frequency of those. Similar results are discussed for a rotating skewed metal plate, but the modulated waveforms is a function of the rotating frequency. Numerical results based on our ECM are presented and compared with those of Sikta's and PO solution.

• 대한기계학회논문집
• /
• 제15권1호
• /
• pp.341-348
• /
• 1991

본 연구에서는 S$_{4}$ 구분종좌법으로 사각형매질내 복사와 전도가 연계된 열전달문제를 수치해석하여, 유한요소법 및 적분함수를 사용하여 구한 해와 정확도를 비교하였으며 산란매질에 대하여도 계산을 수행하여 그결과를 예측하였다.복사열전 달이 전도열전달에 어떠한 영향을 주는가를 좀더 명확히 알아보기 위하여 열선(heatl- ine)을 정의하여 이의 분포도 도시하였다.

• 한국전자파학회지:전자파기술
• /
• 제3권2호
• /
• pp.16-21
• /
• 1992

플란지 평해도파관에 의한 TE-모드의 산란 및 수신을 해석한다. 푸리에 변환을 이요하여 주파수 영역에서 산란파를 표시하여, 경계조건을 사용하여 산란파의 점근해를 구하였다. 수치해석을 통하여 산란특성을 조사하였다.

• 조명전기설비학회논문지
• /
• 제28권10호
• /
• pp.49-55
• /
• 2014

This paper is basic study for development of an advanced photoelectric type smoke detector that has high reliability by reducing the occurrence of nuisance alarms. This paper was attempted to distinguish optical characteristics of the typical fire smoke particle and non-fire smoke particle. According to UL 268 standards, three types of test fires (the paper, the wood and the flammable liquid) were used in this paper for measurement of the fire smoke particles, and the water vapor and the cigarette smoke that were known as the main cause of the nuisance alarms were also used for the non-fire smoke particles. A smoke detection chamber was created, which was equipped with one light source and several light sensors for enabling simultaneous detection of light extinction and scattering, respectively. This paper analyzes the optical characteristics of each smoke particle using this chamber.