• Journal of electromagnetic engineering and science
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• 제14권4호
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• pp.332-335
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• 2014

This paper investigates the phase singularity problem in microwave image reconstruction utilizing unwrapped phase data. The measured phases of the electric fields in most microwave measurement systems are wrapped. Thus, a certain phase unwrapping process is necessary for reconstruction of the image of a high contrast object. This unwrapping, however, is difficult in the presence of scattering nulls on/near the unwrapping path. At the null point, the phase value will be rendered, resulting in a poor image reconstruction. In this paper, we investigate the phase singularity arising from electromagnetic scattering nulls in microwave breast tomographic imaging. We then propose a transformation technique for the measured electric fields that avoids phase singularity.

• Bulletin of the Korean Chemical Society
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• 제35권4호
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• pp.1061-1066
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• 2014

Time-dependent formulations of the reactive scattering theory based on the wavepacket correlation functions with the M${\phi}$ller wavepackets for the electronically nonadiabatic reactions are presented. The calculations of state-to-state reactive probabilities for the quasi-Jahn-Teller scattering model system were performed. The conical intersection (CI) effects are investigated by comparing the results of the two-surface nonadiabatic calculations and the single surface adiabatic approximation. It was found that the results of the two-surface nonadiabatic calculations show interesting features in the reaction probability due to the conical intersection. Single surface adiabatic calculations with extended Born-Oppenheimer approximation using simple wavepacket phase factor was found to be able to reproduce the CI effect semi-quantitatively, while the single surface calculations with the usual adiabatic approximation cannot describe the scattering process for the Jahn-Teller model correctly.

• 산업기술연구
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• 제9권
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• pp.79-85
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• 1989

In this paper, the static limit of Helmhortz equation is discussed in the analysis of acoustic wave scattering in a waveguide. Boundary integral equation method is used to formulate the scattering process in the exerior of the scatterer and finite element method in the interior of the scatterer. And hybrid Ray-Mode Method is used the provide the Green's function of the waveguide. The proposed algorithm is applied to a sample poblem with arbitrary scatterer in a waveguide. The results are compared with those of Laplace's equation which is the governing equation in the static problems.

• 한국응용과학기술학회지
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• 제29권1호
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• pp.122-128
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• 2012

L-arpartic acid의 산란혼탁매질에서 형광, 산란과 응집의 영향은 파장과 산란된 형광세기로 나타내는데, laser induced fluorescence(LIF) 분광학에 의한 분자특성으로 나타난다. 산란매질에서 광학적 효과는 광학적 파라미터들(${\mu}_s$, ${\mu}_a$, ${\mu}_t$)에 의해 표현되고 응집은 고-액상 분리공정에서 중요하게 활용되고 있다. 따라서 입자가 서로 접근될 때 콜로이드 입자들의 상호작용을 LIF와 응집효과로 분석하였다. 레이저 광원에서 검출기까지 농도의 함수에 의해 농도가 묽어짐에 따라 산란세기가 기하급수적으로 감소함을 알 수 있다. 이는 유지화학, 생의학 생성물, 레이저 의학, 의공학 분야적용에 LIF와 입자이동 현상은 아주 적합한 모델 연구에 큰 도움이 될 것이다.

• 한국응용과학기술학회지
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• 제31권2호
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• pp.167-175
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• 2014

혼탁매질에서 형광, 산란과 응집의 영향은 파장과 산란된 형광세기로 나타내는데, laser induced fluorescence(LIF) 분광학에 의한 분자특성으로 나타난다. 산란매질에서 광학적 효과는 광학적 파라미터들(${\mu}_s$, ${\mu}_a$, ${\mu}_t$)에 의해 표현되고 응집은 고-액상 분리공정과 Photodynamic therapy에서 중요하게 활용되고 있다. 따라서 입자가 서로 접근될 때 콜로이드 입자들의 상호작용을 LIF와 응집효과로 분석하였다. 우리는 레이저 광원에서 검출기까지 농도의 함수에 의해 in vitro 시료의 산란과 형광 스펙트라를 측정하였다. 산란계수 ${\mu}_s$는 산란체의 입자가 증가함에 크게 나타났다. 그리하여 Phorphyrin A는 Phorphyrin C보다 산란세기는 증가하였으나, 침투깊이 ${\delta}$는 감소하였다.

• 한국응용과학기술학회지
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• 제33권1호
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• pp.136-142
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• 2016

무질서 매질에서 형광, 산란과 응집의 영향은 파장과 산란된 형광세기로 나타내는데, laser induced fluorescence(LIF) 분광학에 의한 분자특성으로 나타난다. 산란매질에서 광학적 효과는 광학적 파라미터들(${\mu}_s$, ${\mu}_a$, ${\mu}_t$)에 의해 표현되고 응집은 고-액상 분리공정과 Photodynamic therapy에서 중요하게 활용되고 있다. 따라서 입자가 서로 접근될 때 콜로이드 입자들의 상호작용을 LIF와 응집효과로 분석하였다. 우리는 레이저 광원에서 검출기까지 거리의 함수에 의해 in vitro 시료의 산란과 형광 스펙트라를 측정하였다. 산란계수 ${\mu}_s$는 산란체의 입자가 증가함에 크게 나타났다. 그리하여 purple membrane vesicle과 ${\beta}$-carotene의 혼합물의 매질에서 광원에서 검출기에 의한 거리에 대한 측정된 값(I, ${\delta}$)이 거리가 가까워짐에 따라 크게 나타났다.

• Journal of Plant Biology
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• 제17권3호
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• pp.113-117
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• 1974

In counting chromosome number and karyotype study, it is necessary to let chromosomes on metaphase by pretreatment before fixation. For this purpose, colchicine, or 8-oxyquinoline are generally used. The author found out that chromosomes could be scattered by illuminating cyanoferrate complex solution in which root-tips were sunk. As materials, 8 sorts of plant such as Allium fisturosum, allium tuberosum Rottler, Triticum vulgare were used. Their root-tips were sunk on the bottom of beaker in potassium ferricyanide solution $3{\times}10-4M$ and illuminated through the solution by sterilizing lamp for 1~2 hours in dark room, keeping 10 cm distance from light source to the surface of solution and 2cm depth of solution. Then again, they were illuminated to the light which was somewhat weaker intensity than the former (distance, 16cm; depth, 3cm) for 1.5~2 hours after immersed in 1/100N-HCl and washed in water for each 5minutes. By such methods chromosomes could be scattered. About the mechanism of scattering, it is supposed that CN and Fe(CN)x ions $(x {\leq}5)$ which were gradually produced in the process of photodissociation acted together on the scattering of chromosomes.

• 반도체디스플레이기술학회지
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• 제21권3호
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• pp.39-44
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• 2022

The light extraction technology for improving the light efficiency of OLEDs is the core technology for extracting the light inside the OLEDs to the outside. This study demonstrates a simple method to generate random nanostructures (RNSs) containing high refractive index nanoparticles to improve light extraction and viewing angle characteristics. A simple dry low-temperature process makes the nanostructured scattering layer on the polymer resin widely used in the industry. The scattering layer has the shape of randomly distributed nanorods. To control optical properties, we focused on changing the shape and density of RNSs and adjusting the concentration of high refractive index nanoparticles. As a result, the film of the present invention exhibits a perpendicular transmittance of 85% at a wavelength of 550 nm. This film was used as a scattering layer to reduce substrate mode loss and improve EL efficiency in OLEDs.

• The Korean Journal of Ceramics
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• 제3권1호
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• pp.29-33
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• 1997

Four diamond films were deposited by the microwave plasma assisted chemical vapor deposition method varying CH4 concentration from 2.5 to 10% in the feeding gases. Thermal conductivity was measured on these free standing films by the steady state method from 80 K to 400K. They showed higher thermal conductivity as the film deposited with lower methane concentration. One exception, 7.79% methane concentration deposited film, was observed to be the highest thermal conductivity. Phonon scattering processes were considered to analyze the thermal conductivity with the full Callaway model. The grain size and the concentration of the extended and the point defects were used as the fitting parameters. Microstructure of diamond films was investigated with the scanning electron microscopy and Raman spectroscopy.

• Journal of Advanced Marine Engineering and Technology
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• 제37권2호
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• pp.144-148
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• 2013

In this paper, the ultra water-repellent thin films were prepared by RF PECVD. On the basis of surface morphology, chemical bonding states and plasma diagnostics, a formation model of clusters for the ultra water-repellent films was discussed from considerations of formation process and laser scattering results. Moreover, using laser scattering method, the relative change of quantity of nano-clusters or size of agglomerates could be confirmed. From the results, the films were deposited with nano-clusters and those of agglomerates, which formed in organosilicon plasma, and formation of agglomerates were depended on the deposition time.