• 대한전자공학회논문지TC
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• 제45권8호
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• pp.114-120
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• 2008

본 논문에서는 단락 개방 Calibration (SOC) 방법을 이용하여 MIM 구조로 구성된 커패시터의 기생 소자 값들을 추출하였다. Strip line 으로 구성된 short, open, MIM 구조들의 산란 파라미터 행렬들은 전자기 시뮬레이터 및 벡터 네트웍 분석기를 이용하여 측정되었다. 전자기 시뮬레이션들은 3차원 구조 해석에 적합해왔던 유한 유소법 (FEM)을 이용하여 수행되었다. 적층 구조 내부에 형성된 MIM 커패시터의 전자기 영향들은 집중 소자들로 구성된 II 형 등가 회로로 제안되었고, 2 포트 네트웍 해석을 수행함으로써, 측정된 산란 파라미터들과 등가회로 소자들 간의 관계를 보였다. 제안된 SOC 방법을 이용하여 추출된 집중 소자들은 주파수 독립적인 결과를 나타낸다.

• 한국구조물진단유지관리공학회 논문집
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• 제26권5호
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• pp.103-111
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• 2022

미세먼지는 생태학적으로 심각한 문제를 발생시키는 원인이고, 건설현장에서 발생되는 비산먼지는 국내 미세먼지의 주요 발생원이다. 그러나 레미콘 플랜트 현장을 포함한 건설현장에서는 비산먼지 발생단계에서 모니터링은 거의 이루어지지 않고 있으며, 방진덮개, 방진벽 및 방진망, 살수시설, 세륜시설 등 수동적인 제거 방안들이 대부분인 실정이다. 비산먼지는 발생한 뒤 퍼지고 나면 관리하는 것이 매우 어렵기 때문에 발생을 억제하거나 발생단계에서 즉시 제거하는 것이 매우 중요하며, 비산먼지 발생단계에서 실시간 모니터링을 통해 발생 경향을 파악한 뒤 비산먼지 억제 및 제거를 위한 환경 유지관리 대책을 세우는 것이 필요하다. 따라서, 본 연구에서는 레미콘 플랜트의 비산먼지 환경 유지관리를 위하여 골재하차장을 중심으로 비산먼지 질량농도를 모니터링하고 발생 경향을 분석하였다.

• 한국구조물진단유지관리공학회 논문집
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• 제27권4호
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• pp.70-77
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• 2023

미세먼지는 생태학적으로 심각한 문제를 발생시키는 원인이고, 건설현장에서 발생되는 비산먼지는 국내 미세먼지의 주요 발생 원인이다. 그러나 콘크리트 제조업 현장을 포함한 건설 현장에서는 비산먼지 발생단계에서 측정은 거의 이루어지지 않고 있으며, 수동적인 제거방안들이 대부분인 실정이다. 따라서, 본 연구에서는 콘크리트 제조업에서 골재 하역시 발생하는 비산먼지를 발생단계에서 관리하기 적합한 비산먼지 측정 방법을 선정하고, 자동 비산먼지 저감시스템을 골재 하역장에 적용하여 저감시스템 작동 여부에 따른 비산먼지 저감량을 분석하는 것을 목적으로 하였다. 결과적으로, 베타선흡수법과 광산란법의 비교측정을 통하여 광산란법의 신뢰성을 확보하였고, 광산란법 보정계수를 산출하여 콘크리트 제조업 현장 비산먼지 질량농도 측정값에 적용하였다. 또한, 자동 비산먼지 저감시스템 작동 여부에 따른 비산먼지 저감률을 도출하였다.

• 전기학회논문지
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• 제56권9호
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• pp.1643-1647
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• 2007

Recently, there is a need for research concerning the technologies and precaution methods against electronic bomb assaults. There lays perplex constitution and much coupling phenomenon in this type of system, and thus requires much time and memory in order to translate the system with the existing translation methods. Applying the EMT (Electromagnetic Topology) would prove much more efficient. In this paper, EMT has been applied to the circuit-like micro system, previously employed in micro systems. Also, each section has been interpreted using the BLT (Baum, Liu, Tesche) equation using the EMT, then reconstructed, consequentially interpreting an entire system. In this paper, a simple circuit containing active and passive elements based on a CPW has been interpreted employing the BLT equation, and has been proven by experiment using the circuit simulation, a simulation officially recognized for its accuracy in interpreting small structures. The interpretation results have been presented by an S-parameter, and by comparing the interpretation results attained through the BLT equation and that from common simulation to that from experimentation, that the BLT equation turned out to be the most reliable interpretation method could be found.

• 수산해양교육연구
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• 제17권1호
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• pp.35-47
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• 2005

The purpose of this study is to investigate various kinds of discipline problems in middle school classrooms, and the differences in severity and frequency of the classroom discipline problems between male and female students' classrooms in middle schools. This study shows that the discipline problems in the middle school classrooms include using a cellular phone, chattering, sleeping, chewing gum, reading comic books, asking useless questions, challenging a teacher, fighting, calling names, skipping class, throwing trash in the classroom, breaking classroom equipment, creating disorder, losing materials, playing with a ball in the classroom, gambling, and so on. Generally, male students recognized the severity of the classroom discipline problems more than the female students. However, it is shown that the frequency of discipline problems in male students' classrooms is higher than that in female students' classrooms. From the results of this study, male students have more active discipline problems (playing with a ball in the classroom, throwing trash in the classroom, coming to class late, gambling, cutting in line, and so on). On the other hand, female students have more passive discipline problems (making a noise by using a cellular phone, asking useless questions, sending messages to a classmate, studying other subjects, scattering, and so on).

• 한국전기전자재료학회논문지
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• 제22권8호
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• pp.641-644
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• 2009

We have studied on the microwave characteristics for the meander type inductors on the MgO substrates and $Al_2O_3$ substrates by employing 3-D high frequency simulation, respectively. Proper designs of meander type inductors were proposed and confirmed through the high frequency simulations, 5, 7, 9, 11, and 13 turns meander type inductors have been choose to analyze the electrical properties for the microwave passive component applications. The Al top electrodes have 282 nm length, 45 nm width, 100 nm thickness and 15 nm gap. The simulations were carried out from 50 MHz to 30 GHz, Frequency dependent inductances and quality factor were calculated by employing the equivalent circuit model of meander type inductors. The self resonances frequency of meander type inductor were shifted from high frequency to low frequency range as the number of the turn of inductors was increased. From the microwave simulations, the inductances and quality factors of meander type inductors were extracted through the scattering parameter.

• Journal of electromagnetic engineering and science
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• 제17권4호
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• pp.169-177
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• 2017

The role of electromagnetic (EM) waves in magnetic fusion plasma-ranging from radio frequency (RF) to microwaves-has been extremely important, and understanding of EM wave propagation and related technology in this field has significantly advanced magnetic fusion plasma research. Auxiliary heating and current drive systems, aided by various forms of high-power RF and microwave sources, have contributed to achieving the required steady-state operation of plasmas with high temperatures (i.e., up to approximately 10 keV; 1 eV=10000 K) that are suitable for future fusion reactors. Here, various resonance values and cut-off characteristics of wave propagation in plasmas with a nonuniform magnetic field are used to optimize the efficiency of heating and current drive systems. In diagnostic applications, passive emissions and active sources in this frequency range are used to measure plasma parameters and dynamics; in particular, measurements of electron cyclotron emissions (ECEs) provide profile information regarding electron temperature. Recent developments in state-of-the-art 2D microwave imaging systems that measure fluctuations in electron temperature and density are largely based on ECE. The scattering process, phase delays, reflection/diffraction, and the polarization of actively launched EM waves provide us with the physics of magnetohydrodynamic instabilities and transport physics.

• 한국군사과학기술학회지
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• 제10권2호
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• pp.90-99
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• 2007

We demonstrate an 80km-reach 64-channel DWDM-PON based on wavelength-locked F-P LDs by changing the position of the C-band BLS for upstream channels from the CO to the RN. It mitigates the necessity of the high power C-band BLS and its handling problems. It also reduces back scattering induced penalty. We obtained less than $10^{-6}$ PLRs in all 128channels through 80km SMF. We also demonstrate a 240km-reach DWDM-PON based on wavelength-locked F-P LDs by adding a bidirectional erbium-doped fiber amplifier(EDFA). We show packet-loss-free transmission in all 128channels at 125 Mb/s per channel over 240km SMF We report the detuning effect of arrayed waveguide gratings(AWGs) and crosstalk effect in the implemented system. We Propose an architecture of a next generation defense wire communication system with the demonstrated long-reach DWDM-PON.

• 폴리머
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• 제30권6호
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• pp.512-518
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• 2006

양친성 블록공중합체는 생분해성 고분자인 poly((R)-3-hydroxybutyrie acid), PHB와 친수성 고분자인 poly(ethylene glycol), PEG를 이용하여 제조되었다. 미생물에 의해 생산된 분자량이 수십만인 PHB는 약물전달용 재료로 적합하지 않으므로 산 촉매 가수분해를 통해 분자량이 $3000{\sim}30000$을 가지도록 조절되었다. 공중합체를 수용액에 넣으면, 고분자들은 자기 조립에 의해 친수성인 PEG가 소수성인 PHB를 감싸는 형태의 고분자 미셀을 형성한다. 형성된 고분자 미셀은 생분해성과 생체적합성을 가지면서 생체 내에서 낮은 독성과 환자 친화적인 특성을 가지므로 약물 전달체로의 이용이 가능하다. 양친성 블록 공중합체는 PHB에 PEG를 도입한 것으로 에스테르교환(transesterification) 반응을 통해 유도되었다. PEG는 친수성 블록의 형성과 반응성을 향상시키기 위해 말단의 작용기를 개질한 후 사용되었다. 양친성 블록 공중합체 형성에 대한 열적 특성과 화학적 구조 분석은 DSC, FTIR, $^1H-NMR$을 사용하여 알아보았다. 임계 미셀 농도(critical micelle concentration, CMC)는 고분자 미셀이 형성되는 시점으로 형광 분광기를 사용하여 분석한 결과 $5{\times}10^{-5}g/L$ 부근에서 측정되었다. 수용액 상의 고분자 미셀은 냉동 건조 후, 분말형태의 나노입자를 얻었다. 고분자 미셀의 크기는 dynamic light scattering으로 측정한 결과 약 130 nm 정도로 나타났다. 또한 atomic force microscopy 측정을 통해 크기가 약 130 nm 정도인 구형 입자를 확인하였다. 나노입자가 형성된 고분자 미셀은 소수성 약물을 담지하여 수동적 표적지향형 약물 전달용 수송체로 이용이 가능할 것이다.

• 한국의학물리학회지:의학물리
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• 제30권4호
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• pp.112-119
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• 2019

Purpose: The advantages of ocular proton therapy are that it spares the optic nerve and delivers the minimal dose to normal surrounding tissues. In this study, it developed a solid eye phantom that enabled us to perform quality assurance (QA) to verify the dose and beam range for passive single scattering proton therapy using a single phantom. For this purpose, a new solid eye phantom with a polymethyl-methacrylate (PMMA) wedge was developed using film dosimetry and an ionization chamber. Methods: The typical beam shape used for eye treatment is approximately 3 cm in diameter and the beam range is below 5 cm. Since proton therapy has a problem with beam range uncertainty due to differences in the stopping power of normal tissue, bone, air, etc, the beam range should be confirmed before treatment. A film can be placed on the slope of the phantom to evaluate the Spread-out Bragg Peak based on the water equivalent thickness value of PMMA on the film. In addition, an ionization chamber (Pin-point, PTW 31014) can be inserted into a hole in the phantom to measure the absolute dose. Results: The eye phantom was used for independent patient-specific QA. The differences in the output and beam range between the measurement and the planned treatment were less than 1.5% and 0.1 cm, respectively. Conclusions: An eye phantom was developed and the performance was successfully validated. The phantom can be employed to verify the output and beam range for ocular proton therapy.