• Proceedings of the Korean Society of Medical Physics Conference
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• 2004.11a
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• pp.149-152
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• 2004

물 흡수선량 표준에 토대를 두고 있는 프로토콜에서는 저에너지 전자선의 경우 평행평판형이온함의 사용과 기준 선질 $^{60}$CO 감마선의 물 흡수선량 교정정수를 받은 원통형이온함을 사용하여 고에너지 전자선에서 평행평판형이온함을 교차교정하도록 권고하고 있다. 따라서 본 연구에서는 국제원자력기구의 프로토콜(IAEA TRS-398)에서 권고하고 있는 절차에 따라 저에너지 전자선에 대한 원통형이온함의 선질보정정수를 계산하고, 원통형이온함과 평행평판형이온함의 교정방법에 따른 흡수선량을 상호 비교하였다. 그 결과 전자선에너지 10 MeV 이상에서는 두 이온함간의 선량이 잘 일치하였으나 전자선에너지 6, 9 MeV에서 최대 3.3%까지 선량 차이를 보여 저에너지 전자선에서는 반드시 평형판판형이온함의 사용하여 선량측정 할 것을 권고한다. 교정방법 차이에 의한 평행평판형이온함의 선량은 서로 잘 일치하는 것으로 나타나 표준기관에서 직접 교정받은 $^{60}$Co 감마선의 물 흡수선량교정정수를 사용하여 전자선 물 흡수선량을 결정해도 큰 영향은 없을 듯하다. 또한 평행평판형이온함을 교차 교정하기 위한 전자선 에너지에 따른 흡수선량을 상호 비교한 결과 20MeV이외 12, 16 MeV의 전자선 에너지에서도 잘 일치하여 교차교정을 위한 전자선의 기준 선질에 대한 연구가 더 진행되어야 한다고 사료된다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.3
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• pp.992-1000
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• 1991

본 연구에서는 두개의 수직 평행 평판의 혼합대류 열전달에 대하여 평판간격 과 평판온도를 변수로 하여 수치해석과 실험을 행하였다.

• Progress in Medical Physics
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• v.13 no.2
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• pp.69-73
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• 2002

Exposure measurement data with parallel plate ionization chambers were known to depend on the polarity ($k_{pol}$) effect. In this work, the polarity effect were investigated for three parallel plate ionization chambers with different volume. The ionization chamber was fabricated using acrylic plate for the chamber medium and printed circuit board for electrical configuration. The various sizes of the sensitive volumes designed so far were 0.9, 1.9, and 3.1 co. High voltage generator was fabricated using the conventional 9 V batteries to apply the high voltage (300-500 V) to the electrode of the parallel plate ionization chamber. The gap between two electrodes ranged from 3, 6, and 10mm. As the result of our experiment, the polarity effect was within 0.5% in photon beam and 1% to 3.5% in the electron beams. Among electron beams, 16 MeV beam, which had highest energy, showed less polarity effect than electron beams with other energies.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.6
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• pp.731-739
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• 2012

Transverse electric modes in parallel plate waveguide of which cut-off frequency is much lower than that of $TE_1$ and $TM_1$ mode generally known as the lowest higher order mode are investigated. Electric and magnetic field components of the modes are evaluated with the assumption that boundaries at both sides are perfect magnetic conductor. The existence of these modes are verified by simulation and experimental measurement of parallel plate waveguide cavity. Changed characteristics from the fact that the boundaries are imperfect are studied.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.530-533
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• 2003

본 논문에서는 2GHz의 패치폭과 그라운드면의 폭이 같은 QMSA의 구조를 설계 및 제작하였고, QMSA의 구조를 변형하여 용량을 장하한 QMSA와 기생소자를 갖는 QMSA를 제안하였다. QMSA의 구조는 한 쪽 끝이 전기적으로 단락된 λ/4의 구조로 설계하였으며, 용량을 갖는 QMSA는 상측 평행 평판과 하측 평행 평판 사이의 용량을 구성시킴으로써 리턴로스와 공진주파수의 변화를 비교 평가하였다. 또한, 기생소자를 갖는 QMSA의 구조는 상측 평행 평판위에 기생소자를 가변함으로써 안테나를 소형화할 수 있었다. QMSA는 2GHz의 중심주파수를 갖고 2%의 대역폭을 갖으며, 용량의 변화와 기생소자의 길이에 따라 공진주파수의 변화를 보였다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.8
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• pp.41-46
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• 2008

This paper conducts the research on the variation in the characteristics of the resonance and impedance of the metallic parallel plates due to the replacement of the normal dielectric substrate by the metamaterial. The ENG(${\epsilon}<0$), MNG(${\mu}<0}$) and DNG(${\epsilon},{\mu}<0$) types of metamaterial as well as the DPS(Double Positive) material are taken into consideration a full-wave modal analysis method known for accurate computation, as the SRR-kind of Lorentz model for permittivity and metal wire-periodic array-kind of Drude model for permeability, and the behaviors of parallel plates' resonance mode and impedance are observed. Based upon the observation, the design guidelines for the substrate can be addressed regrading how to suppress the parallel plates' spurious resonance modes that degrade the quality of the electronic equipment.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.4
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• pp.765-774
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• 1992

The effect of the interactive flow on convective heat transfer from two vertical isothermal parallel plates have been studied numerically by the finite difference method. The Reynolds number, Grashof number, the relative length, L$_{2}$/L$_{1}$, and the dimensionless plate spacing, b/L$_{1}$ are varied as parameters. In case of outside mean Nusselt number, left outside mean Nusselt numbers show same values as L$_{2}$/L$_{1}$ and b/L$_{1}$ increase, but right outside mean Nusselt numbers decrease as L$_{2}$/L$_{1}$ increases. The inside mean Nusselt numbers are constant at narrow spacings and increase at wide spacings as Grashof numbers increase. The optimun plate spacing on left inside mean Nusselt numbers is b/L$_{1}$=0.4 at Re=100 and b/L$_{1}$=0.3 at Re=200. For the right inside mean Nusselt number, the optimum plate spacings move to the narrow spacing as Reynolds numbers increase and L$_{2}$/L$_{1}$ decrease.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.11
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• pp.2260-2266
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• 2009

In this paper, the problem of electromagnetic coupling between a slit fed by a flanged parallel-plate waveguide (FPPW) and a nearby conducting strip parallel to the slit is studied as a simplified problem for a near-field scanning microscopy (NSM). The characteristics of the FPPW are investigated from the results for the variations of the equivalent slit admittance, the reactive powers near the slit inside and outside the FPPW, the magnitude and phase of the voltage reflection coefficient of the TEM wave. The performance of the proposed apparatus as an NSM is tested by examining the effects of various geometrical parameters such as guide height, slit width, strip width, distance between slit and strip, and the ratio of slit width to guide height on the magnitude and phase of the voltage reflection coefficient of the TEM wave. From the results for the voltage reflection coefficient against the strip offset from the slit, it is found that a slit in the FPPW with smaller guide height gives higher scanning resolution and the phase variation is more sensitive than the magnitude variation.

• Progress in Medical Physics
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• v.13 no.2
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• pp.55-61
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• 2002

In this work, EPM (effective point of measurement) of parallel plate ionization chamber with three different spacing were investigated. If the plate separation is less than 2 mm one generally assumes that the effective point of measurement is just behind the front window of the parallel plate ionization chamber. For chamber with relatively large separation, such as the ones used for very accurate exposure measurements, this assumption breaks down and the EPM depends on plate separation and thickness of the front window. For parallel plate chambers, conventional theoretical analyses suggest that the EPM is the inner front wall and that it shifts towards the geometric centre of the chamber as the plate separation increases. The PP-IC (parallel plate ionization chamber) is fabricated using acrylic plate for the chamber medium and printed circuit board for electrical configuration. The various sizes of the sensitive volumes designed so far are 0.9, 1.9, and 3.1 cc. The gap between two electrodes ranges from 3, 6, and 10mm. Also the charge-to-voltage converter is designed to collect the electrons produced in the ionization chamber cavity. As the result of our experiment, the EPM shift was within 0.6 mm in photon beams and 0.4 mm to 2.5 mm in electron beams for the plate separation of 6 mm and 10 mm. EPM shifts towards the geometric center of the chamber as the plate separation increases.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.2
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• pp.299-306
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• 1989

The combined convective heat transfer from vertical parallel plates with constant temperature has been studied by numerical method. The governing equations for the system are solved by the finite difference method and successive over relaxation scheme for Re$_{L}$ = 50 - 500, Gr = 10$^{4}$, Pr = 0.7. Results for various plate spacings and plate lengths are as follows ; For various plate spacings, the mean Nusselt number increases and then decreases as the dimensionless plate spacing increases. The optimum plate spacing for maximum mean Nusselt number decreases with increasing Reynolds number and can be expressed as a function of Reynolds number. For various plate lengths, the mean plate Nudest number increases as the dimensionless plate length decreases and Reynolds number increases.