• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.4
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• pp.21-26
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• 2019

In this paper, TE(transverse electric) scattering problems by a resistive strip grating between a double dielectric layer are analyzed by using the PMM(point matching method) known as a numerical method of electromagnetic fileld. The boundary conditions are applied to obtain the unknown field coefficients, the scattered electromagnetic fields are expanded in a series of Floquet mode functions, and the resistive boundary condition is applied to analysis of the resistive strip. The numerical results for the normalized reflected and transmitted power are analyzed by according as the width and spacing of resistive strip, the relative permittivity and thickness of the double dielectric layers, incident angles, and uniform resisitivity. Typically, the reflected power for the conductive strip increased as the value of the relative dielectric constant increased, the reflected power for the resistive strip with uniform resistivity decreased as the value of the resisvivity increased. The numerical results for the presented structure of this paper are shown in good agreement compared to those of the existing papers.

• Composites Research
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• v.34 no.6
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• pp.387-393
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• 2021

This paper investigated the electrical properties of multiwall carbon nanotube reinforced polydimethylsiloxane (CNT-PDMS) strain sensors with copper electrodes on the wet-etched surface. MWCNT-PDMS strain sensors were fabricated according to the wt% of MWCNT. Surfaces on the electrode area were wet-etched with various etching duration and silver epoxy adhesives were spread on the wet-etched surface. Finally, we attached the copper electrodes to the MWCNT-PMDS strain sensors. We checked the electric conductivities by the two-probe method and sensing characteristics under the cyclic loading. We observed the electric conductivity of MWCNT-PDMS strain sensors increased sharply and the scattering of the measured data decreased when the surface of the electrode area was wet-etched. Initial resistances of MWCNT-PDMS strain sensors were inversely proportion to wt% of MWCNT and the etching duration. However, the resistance changing rates under 30% strain increased as wt% of MWCNT and the etching duration increased. Decreasing rate of the electric resistance change after 100 repetitions was smaller when wt% of MWCNT was larger and the etching duration was short. This was due to the low initial resistance of the MWCNT-PMDS strain sensors by the wet-etching.

• Clinical and Experimental Pediatrics
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• v.46 no.8
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• pp.751-757
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• 2003

Purpose : Obesity is a significant health problem with medical and psychological consequences for children and adolescents. The purpose of this study was to assess the correlation between body fat percent using bioelectrical impedance(BI) and other variable methods. Methods : We measured height, weight, body mass index(BMI) and body fat percent by skinfold thickness(ST) and BI in 1,035(496 male; 539 female) children from seven to 18 years of age. The correlation coefficients between BI and each of the other different methods were obtained. The sensitivity and specificity to predict obesity by these several methods were studied. Results : Fat percent estimated by BI analysis and BMI showed a strong correlation(r=0.749). Fat percent estimated by BI analysis and ST showed a very strong correlation(r=0.835). At the 95th percentile cut-off point for BI, ST showed a sensitivity of 57.7%, and a specificity of 97.6% for estimating body fat. At the 95th percentile cut-off point for BI, BMI showed a sensitivity of 84.9%, and a specificity of 99.3% for estimating body fat. Conclusion : The fat percent estimated by BI analysis correlated strongly with ST or BMI. BI analysis is an objective and accurate method for estimating body fat in childhood obesity.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.4 no.1
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• pp.103-108
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• 1968

Resistance to various diseases of Korean native varieties were investigated in field. The results obtained are summarized as follows: 1) The varieties Ubangtchio and Osib-eubthio were moderately resistant to black shank, but Suantchio, Usultchio and Gwangtchio were slightly resistant. Dixie Bright 101, $H_2$ and Bright Yellow 4 were more resistant to black shank than any of the Korean native varieties. 2) Mokgitchio, Ubangtchio and Osib-eubtchio were moderately resistant to black root rot, but Useultchio Suantchio and Hoetchio were susceptible than Others. 3) Muktchio, Hoetchio and Ubangtchio were slightly resistant to wild fire. 4) Osib-ebthio was highly resistant to brown spot, but Ubangtchio, Hyangtchio and Mokgitchio were moderately resistant and Useultchio was susceptible to brown spot, but it was resistant than Bright ellow 4 or Bernhart 1000-1. 5) Hyangtchio was slightly resistant to CMV-Y. According to these results, except Virus disease, Ubangtchio was resistant to all of the above mentioned diseases. Osib-eubtchio, Hoetchio, Hyangtchio and Suantchio showed proferable disease resistant and these might be well utilized as breeding materials.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.4
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• pp.405-411
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• 2014

It needed the calculation of the required tugboat's power to move the damaged vessel to the safe area for reducing the additional damages. In this paper, it was verified the theoretical calculation method on the required power of tugboat through the 93m real ship tests. From the experiments, it was considered that the theoretical calculation method was sufficient to estimate the required power of tugboat. The resistance of the locked propeller was relatively big portions compared with other static resistances such as air resistance, frictional resistance and residual resistance. And dynamic resistance induced by swing movement and yawing was continuously occurred and it also was great effects on the total resistance. In the future, the safety factor will be considered and the exact prediction of ship's resistance will enhance the efficiency of tugboat because of the minimization of safety factor.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.156-156
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• 2009

전자기기의 Slim화에 따라 부품 일장용 Board 기판의 두께도 날로 감소해지고 있다. 이와는 정 반대로 기판의 층수는 더 늘어나고 있다. 이에 따라 기판의 구성요소인 절연재의 두께도 감소하고 있다. 전자기기는 각각의 Module이 저항을 가지는데 이를 matching하기 위해서 각 module이나 package가 가지는 저항값을 상호 비슷하게 맞춘다. 하지만, 기판의 절연재의 두께 감소는 이러한 저항값이 낮아지게 한다. 이렇게 낮아진 저항값을 높이기 위해서는 전도체의 폭을 줄여야 한다. 하지만, 이렇게 전도체의 폭을 줄이는 것은 기판 제작 비용의 상승 및 제작 물가에 이르게 할 수 있다. 이를 해결하기 위해서는 절연재의 유전율을 낮추는 것이 가장 효과적이다. 본 연구에서는 PCB 기판의 유전율을 낮추기 위해 Liquid Crystalline Polymer(LCP)에 PTFE powder를 넣어 기판 재료의 가능성을 조사하였다. 유전율은 PTFE의 첨가량이 증가함에 따라 감소하여 40wt% 첨가할 경우 유전율이 2.4 정도로 낮아졌다. 이에 반해 열팽창계수는 증가가 크지 않고 peel strength는 감소함을 알 수 있었다.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.169-169
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• 2010

박막형 CIGS 태양전지의 배면전극으로 사용되는 Mo 박막은 낮은 저항으로 인한 전기전도성과 열적 안전성이 아주 우수하다. 연구에서는 연성 CIGS 태양전지의 제조를 위한 Mo 배면전극의 대면적 증착기술에 관한 것으로 DC Magnetron Sputtering 공정을 이용하여 전주기술을 통한 Ni-Fe계 연성기판재 위에 졸걸법으로 합성된 $SiO_2$ 절연박막에 Mo 박막을 증착하는 것을 목적으로 하고 있다. 실험에서는 연성기판재 대신 시편을 Sodalime glass, Si wafer, SUS계 소재를 사용하여 스퍼터링 공정에 의한 Mo 박막을 증착하였다. 실험에서 타겟에 인가되는 전력과 공정압력을 변수로 하여 Mo 박막의 증착율, 전기저항성을 측정하였다. 타겟의 크기는 $80mm{\times}350mm$, 타겟과 기판간 거리 20cm 이었으며, 공정 압력은 2~50 mtorr 영역에서 인가전력을 0.5-1.5kW로 하였다. Mo 박막의 증착율과 전기적 특성을 측정하기 위하여 $\alpha$-step과 4-point probe(CMT-SR 1000N)를 이용하였다. 그리고 Mo 박막의 잔류응력을 측정하기 위하여 잔류응력측정기를 이용하였다. Mo 박막의 미세구조분석을 위하여 SEM 및 XRD를 분석을 실시하였다. 배면전극으로서 전기저항성은 공정압력에 따라 좌우 되었으며, 2 mTorr 공정압력과 1.5kW의 전력에서 최소값인 $8.2\;{\mu}{\Omega}-cm$의 저항값과 증착율 약 $6\;{\mu}/h$를 보였다. 기판재와의 밀착성과 관련한 잔류응력 측정과 XRD분석을 통한 결정립 크기를 분석하여 공정압력에 따른 Mo 박막의 잔류응력과 전기 저항 및 결정립 크기의 상관관계를 조사하였다. 그리고 대면적 CIGS 증착공정을 위해 직각형 타겟을 통해 증착된 Mo 박막의 증착분포를 20cm 이내 조사하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.413-413
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• 2013

대면적 터치패널은 현재까지 저항막 방식, 적외선, Camera 방식을 주로 사용하고 있다. 저항막 방식의 Sensitivity, 높은 가격, 적외선 방식의 경우 빛의 간섭에 의한 오동작이 일어날 수 있는 문제를 가지고 있다. 최근의 Mobile용 터치스크린은 정전용량 방식의 터치기술 채택으로 저항막, 적외선, Camera 방식의 모든 단점을 해소할 수 있으나 터치 스크린 면적이 커지게 되면서 요구저항을 맞출 수 없는 문제로 현재 크기의 제한적이다. 본 연구에서는 완전일체형 터치(G2 Touch Hybrid) 방식의 ITO 터치필름을 사용하지 않고, 강화유리 기판을 사용하여 저(低)저항, 고(高)투과, 대형화(15 Inch), 경량화를 고려한 Zero-gap ITO를 코팅한 커버 유리용 투명전극에 대하여 전기적, 광학적, 구조적, 표면적 특성을 분석하였다. ITO 박막의 두께를 최소화하여 패턴 인비저블의 특성을 갖는 것이 필요로 하는데, 이는 ITO박막 패턴후에 패턴이 보이지 않게 하기 위해서이며, 이러한 시장의 요구를 충족하기 위해 RF/DC 고자력 Magnetron Sputtering System을 사용하여 면저항 $80{\Omega}$/${\Box}$, 표면특성 Rp-v 2.1 nm, 최고 광투과율 90.5%@550 nm, 반사율 차이 0.5 이하의 특성을 확인하였다. 또한, 저항 경시변화를 줄이기 위해서 Sheath heater를 이용한 진공코팅 중 발생되는 BM Ink out-gassing을 줄여 out-gassing에 의한 박막 손상을 줄일 수 있었으며 진공 성막중 결정성을 갖는 ITO 막을 형성시킬 수 있었다.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.7
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• pp.1-7
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• 1989

For H-polarized incident plane wave, an exact integral expression for the scattered field by an inversely tapered resistive half plane is obtained by using Kontorovich-Lebedev transform. Uniform asymptotic results available for all angles are obtained, and non-uniform asymptotic results which provide the ray-optical interpretation of the calculated scattered field are also obtained. The edge diffraction patterns for several values of inverse proportionality of resistivity are shown. We find out that the results are in agreement with physical reasoning.

• 한국해양학회지
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• v.23 no.3
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• pp.146-157
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• 1988

Properties of porosity, compressional wave velocity, velocity anisotropy, electrical resistivity, and resistivity anisotropy are measured and calculated for two DSDP clay-rich hemipelagic sequences in the northwestern Pacific. Velocity and resistivity increase with burial depth at the expense of decreasing porosity. Profiles of velocity anisotropy and resistivity anisotropy show almost the same trend. Horizontally developed low aspect ratio pores may generate velocity and resistivity anisotropy. The preferred orientation of clay minerals is also believed to be responsible for the observed anisotropy.