• Title, Summary, Keyword: 상대 유전율

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Relative Permittivity of Damaged Concrete Bridge Deck According to the Weather Conditions : A Case Study (기상조건에 따른 손상 교량 바닥판의 상대유전율 변화 고찰)

  • Rhee, Ji-Young;Choi, Jae-Jin
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.4
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    • pp.209-215
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    • 2017
  • Ground Penetrating Radar (GPR) was applied to an evaluation of the concrete condition of bridge decks with asphalt concrete. Deterioration was considered to have occurred when the relative permittivity of a concrete-faced asphalt concrete overlay showed more than 12. The relative permittivity of concrete varied considerably with the levels of porosity and water. In this study, GPR tests were carried out to determine the influence of weather and concrete condition on the relative permittivity for the research subject of an overlaid concrete bridge deck in public service. According to the test results, if bridge decks are in good condition, the relative permittivity of the top concrete of a bridge deck exhibited a normal distribution. After the deck concrete deteriorated, the relative permittivity varied with the amount of penetrated water according to the weather condition and deteriorated status of deck concrete.

EPNP Solver를 이용한 나노포어의 이온전류와 이온전도도 계산

  • Byeon, Min-Hyeon;Hwang, Hyeon-Seok
    • Proceeding of EDISON Challenge
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    • pp.83-90
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    • 2015
  • 본 연구에서는 Poisson-Nernst-Plank (PNP) 식의 해를 구할 수 있는 Edison web-based Poisson-Nernst-Plank (EPNP) Solver를 이용하여 나노포어의 이온선택성 및 박막의 유전율, 그리고 이온 농도가 이온 전류와 이온전도도에 미치는 영향에 대해 알아보았다. 계산 결과로부터 나노포어의 이온선택성에 의해 양이온이 이온전류에 미치는 영향이 매우 크며, top buffer와 bottom buffer의 농도가 증가할수록 이온 전도도 (ion conductance)가 비선형적으로 증가함을 알 수 있었다. top buffer와 bottom buffer 간에 농도 차가 있을 때는 농도 차와 나노포어의 이온선택성에 의해 형성되는 Nernst 전위의 영향으로 I-V 곡선이 비대칭적 형태임을 알 수 있었다. 또한, 나노포어의 상대 유전율을 증가시킬 때 I-V 곡선에서의 양이온 전류는 감소했지만 음이온의 전류는 증가하는 경향을 보였다. 이는 나노포어 내에 배열된 쌍극자에 의한 영향과 전하를 가진 입자가 유전경계 (dielectric boundary)에 접근하면서 형성되는 상전하에 의한 영향이 동시에 존재하기 때문임을 알 수 있었다.

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Design of a Cylindrical Dielectric Resonator Antenna with a Dielectric Clad (유전체 클래드를 갖는 원통형 유전체 공진 안테나 설계)

  • 이권익;김흥수
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.40 no.4
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    • pp.54-59
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    • 2003
  • In this paper, a cylindrical dielectric antenna with dielectric clad is designed and analyzed. Design parameters of a cylindrical dielectric resonator antenna are calculated from the wave equation of cylindrical dielectric. The variations of characteristics of the antenna are analyzed as varying the thickness and the relative permittivity of its clad. From the results, when the ratio of the outside radius of the dielectric clad to the radius of the cylindrical dielectric is 1.3 and the relative permittivity of the dielectric clad is one-third of the cylindrical dielectric resonator antenna, the relative bandwidth of the antenna is 49%, which is improved by 2.3 times than the cylindrical dielectric resonator antennas. However, the thickness and the relative permittivity of the dielectric clad have not effect on the radiation pattern, beamwidth and gain of the antenna.

Detection of Abnormal Area of Ground in Urban Area by Rectification of Ground Penetrating Radar Signal (지하투과레이더 신호의 보정을 통한 도심지 내 지반 이상구간의 검측)

  • Kang, Seonghun;Lee, Jong-Sub;Lee, Sung Jin;Lee, Jin Wook;Hong, Won-Taek
    • The Journal of Engineering Geology
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    • v.27 no.3
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    • pp.217-231
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    • 2017
  • The subsidence of ground in urban area can be caused by the occurrence of the cavity and the change in ground volumetric water content. The objective of this study is the detection of abnormal area of ground in urban area where the cavity or the change in ground volumetric water content is occurred by the ground penetrating radar signal. GPR survey is carried out on the test bed with a circular buried object. From the GPR survey, the signals filtered by the bandpass filtering are measured, and the methods consisting of gain function, time zero, background removal, deconvolution and display gain are applied to the filtered signals. As a result of application of the signal processing methods, the polarity of signal corresponds with the relation of electrical impedance of the cavity and the ground in test bed. In addition, the relative permittivity calculated by GPR signal is compared with that of predicted by volumetric water content of the test bed. The relative permittivities obtained from two different methods show similar values. Therefore, the abnormal area where the change in ground volumetric water content is occurred can be detected from the results of the GPR survey in case the depth of underground utilities is known. Signal processing methods and estimation of relative permittivity performed in this study may be effectively used to detect the abnormal area of ground in urban area.

A Study on sideband Aperture Coupled Microstrip Antenna Using U slot and stub (U 슬롯과 stub를 이용한 개구 결합 급전 방식의 광대역 마이크로스트립 안테나에 관한 연구)

  • 김현준;오은실;윤영중
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • pp.377-380
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    • 2000
  • 본 논문에서는 개구 결합 방식의 마이크로스트립 안테나에 U 슬롯과 turning stub를 동시에 사용하여 넓은 대역폭을 갖는 안테나를 설계 및 제작하였다. 상대 유전율이 2.2이고 두께가 61mil인 duroid 5880기판을 사용하여 ITS(Intelligent Transport System)대역인 5.77GHz에서 동작하는 안테나를 설계하였고, VSWR$\leq$2를 기준으로 하여 약 12.4%의 대역폭을 얻을 수 있었다. 그리고 약 7GHz에서 동작하는 안테나에서는 상대 유전율이 2.2이고 두께가 31mil인 5880기판과 1.6mm인 form을 사용하여 VSWR$\leq$1.5를 기준으로 약 11.7%의 대역폭을 얻을 수 있었다. 각각의 경우 U 슬롯만을 사용한 경우와 비교할 때 5.77 GHz에서는 5.7% 7GHz대역에서는 약 4%의 대역폭 개선 효과를 확인할 수 있었다.

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Aperture-Coupled Wideband U-slot Microstrip Patch Antenna at Ku Band (개구 결합 급전 방식의 Ku 밴드 U 슬롯 마이크로스트립 안테나 설계 및 제작)

  • 유명완;이범선
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.10 no.4
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    • pp.636-644
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    • 1999
  • Experimental and simulation results are presented on the Aperture-Coupled microstrip patch antennal with U-shaped slot. Experiment and simulation results include impedance bandwidth, copolar and crosspolar-pattern characteristics and gain measurements. Simulation results show the advantages of U-slotted patch antenna comparing with the normal patch antenna. More than 35% impedance bandwidth is obtained with reasonably restricted cross-polar radiation pattern. The U-slotted radiation element fed by aperture-coupling method can be more easily extended to array structure, compared with that fed by coaxial cable.

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Characteristic Changes in Ground-Penetrating Radar Responses from Dielectric-Filled Nonmetallic Pipes Buried in Inhomogeneous Ground (비균일 지하에 묻혀있는 유전체 충진 비금속관에 의한 지표투과레이다 응답의 특성 변화)

  • Hyun, Seung-Yeup
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.30 no.5
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    • pp.399-406
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    • 2019
  • The variation of ground-penetrating radar(GPR) signal characteristics from dielectric-filled nonmetallic pipes buried in inhomogeneous ground are compared through a numerical simulation. The relative permittivity distribution of the ground is generated by using the continuous random media(CRM) technique. As a function of the relative permittivity of the material filling the nonmetallic pipe buried in the ground media, GPR signals are simulated by using the finite-difference time-domain(FDTD) method. We show that, unlike the case for homogeneous ground, the distortion characteristics of the reflected waves caused by the front convex surface and the rear concave surface of the pipe buried in inhomogeneous ground are different depending on the permittivity contrast between the inside and outside of the pipe.

종란의 수정율에 관련된 요소들

  • 김영환
    • KOREAN POULTRY JOURNAL
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    • v.20 no.7
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    • pp.116-119
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    • 1988
  • 한마리의 수탉은 8$\~$10배수의 암닭을 상대하는 것을 보아도 수탉에 대한 사양관리가 그 유전력 차이보다 얼마나 중요한가를 인식할 필요가 있다.

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Application of Radio Frequency Microwave Technique for Glucose Detection (포도당 검출을 위한 라디오 주파수 마이크로파의 적용)

  • Kim Tae-Woo;Park Byoung-Soo;Cho Dong-Uk;Han Khil-Sung;Cho Tae-Kyung
    • The Journal of the Korea Contents Association
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    • v.4 no.4
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    • pp.171-178
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    • 2004
  • Radio frequency (RF) microwave can be used to predict glucose concentration in a sample. This paper presents preliminary results in determining the concentration by measuring relative permittivity in the solutions of distilled water, saline, human serum, and human blood containing glucose. It was shown that the microwave method has larger penetration depth of about 100times of NIR, than NIR technique in measuring glucose concentration for the tissue like a human muscle. The larger penetration depth of the method has advantages because it is more useful to detect glucose in a human body non-invasively. In the experiments, sensitivity for detecting glucose concentration in blood solutions was almost 57mg/dl at the frequency of approximately 5.8GHz.

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Design and Analysis of 3D Isotropic Metamaterial Bulk Structure Using Thin Wire and SRR (Thin Wire와 SRR을 이용한 3D 등방성 Metamaterial Bulk 구조 설계 및 분석)

  • Kim, Chung-Ju;Lee, Bom-Son
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.22 no.9
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    • pp.919-925
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    • 2011
  • In this paper, we designed and analyzed a 3D isotropic bulk structure consisting of thin wires and SRR's(Split Ring Resonator) with which the permittivity and permeability can be controlled at the same time. For the 3D isotropic bulk structure, first of all, the geometry seen by three main axes must look alike. Thus, we adopted the orthogonal thin wires and symmetrical SRR's. As a result, we constructed metamaterial bulk structures of which effective relative permittivity and permiability are about -0.6 and -1.5, respectively. Its refractive index is about -0.95 in each direction(x, y and z direction). The computed Brillouin dispersion diagram also showed that the proposed structure is almost near isotropic.