• 대한기계학회논문집
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• 제15권2호
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• pp.557-566
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• 1991

The metal V-belt behavior of a continuously variable transmission was investigated analytically and experimentally. Numerical results showed that nondimensional belt radial displacement increased in the radial inward direction for the driven pulley, while that of the driver pulley increased for the first 90 degrees of the active are and decreased with the increasing torque load. Experimental results for the belt radial displacement were in good agreement with the theoretical results. However, the absolute magnitude of the belt radial displacement was so small that the change in the belt displacement could not be measured in the experimental range except for the inlet region of the driven pulley, where the radial inward displacement was observed due to the effect of bending moment. The speed ratio-axial force relationship derived from the belt behavior analysis also showed god agreement with the experiment.

• 한국응용과학기술학회지
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• 제22권3호
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• pp.228-233
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• 2005

Langmuir-Blodgett(LB) technique can speak the best candidate of the future molecular electronic devices. But, precursor as molecular ultrathin film devices require the bulk property that are influenced by the molecular orientation. So, this device is one of current interest in molecular electronic device development of new materials. In this study, quantitative evaluation of molecular orientation in LB films of polyamic acid alkylamine salt was performed analysis experiment comparing the absorption or transmission intensity of the FT-IR spectrometer and reflection or absorption spectra with UV-visible absorption spectra. It could find that the polar angle(${\theta}$) of the dipole moment appears in about $68^{\circ}$ and the tilting angle of the alkyl chain is about $11.5^{\circ}$.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2000년도 추계학술대회논문집
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• pp.53.1-56
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• 2000

Langmuir-Blodgett(LB) technique is the best candidate for the future molecular electronic devices. But, these molecular thin film devices require the bulk properties that are influenced by the molecular orientations. So, this is of current interest in molecular electronic device fabrications of new materials. In this study, quantitative evaluation of molecular orientation in LB films of PAAS was performed by comparing the absorption intensities of the FT-IR transmission and reflection-absorption spectra and the polarized UV/visible absorption spectra. It was found that the polar angle($\theta$) of the dipole moment is about 68$^{\circ}$and the tilting angle of the alkyl chain is about $11.5^{\circ}$ .

• 한국경영과학회지
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• 제22권3호
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• pp.145-162
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• 1997

This paper an analytical model for estimating packet waiting times at stations in the DQDB network, where the most upstream station is saturated. This model is useful in comparing the extreme unfairness which downstream stations experience due to their geographical locations in accessing the medium. Each station is modeled as an M/G/1, where the service time is defined to be the time a packet spends in the transmission buffer. The service time is decomposed into five components, and in turn, the first and second moment of each component are derived in three different modes of operation. Simulation experiments are presented for model validation and results are discussed.

• 대한전자공학회논문지
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• 제25권4호
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• pp.366-371
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• 1988

A parallel-plate waveguide with a slit in its upper plate is analysed. An integral equation is formulated for the equivalent magnetic current and solved by the conventional moment method. Numerical results are presented for the magnetic current, reflection and transmission coefficients, a normalized radiated power in the slit, and equivalent circuit parameters. The equivalent circuit parameters are an useful quantities in the study of the E-plane coupled microstrip antennas.

• 한국전자파학회지:전자파기술
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• 제5권3호
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• pp.48-58
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• 1994

본 논문에서는 EMI/EMC 측정용 안테나로서 다이폴 소자가 료차된 삽자형 대수-주기 다이폴 안테나 (CLPDA: Crossed Log-Periodic Dipole Antenna)를 제시하고 모멘트 법과 전송선로 이론을 결합하여 해석하였다. 이 안테나의 광대역 특성을 고려하여 전 주파수 범위에서 임피던스 정합에 중점을 두었으며, 이에 따라 트윈-붐(Twin-boom) 급전 방식을 사용하였다.해석 결과로써 전류 분포, 입력 어드미턴스, 복사 패턴 및 이득을 계산 하였으며, 실제 CLPDA를 설계하여 복사 패턴과 이득을 측정하였다. 제작한 CLPDA의 측정치는 주어진 주파수 범위(200MHz~500MHz)내에서 이론치에 근접하게 나타났다.

• 동력기계공학회지
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• 제19권6호
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• pp.33-38
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• 2015

In this study new CVT(Continuously Variable Transmission) system which is adaptable to a small size electric vehicle is proposed available to gradient response CVT. New pulleys consist of springs adapted driving pulley and driven pulley. At the moment a small electric vehicle drive a slope, new system respond to a gradient as overcoming tensional force of springs. We made prototype of gradient response CVT to test parts performance and travelling performance test. As a result of test, belt pitch diameter varied for high torque direction at the gradient. In the flat travelling, acceleration travelling and gradient travelling performance test, the small electric vehicle with gradient response CVT get improved perfomance than the small electric vehicle with reduction gear.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 춘계학술대회 논문집
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• pp.407-412
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• 2013

In dry wall, noise is passed through gypsum board and stud. Noise makes gypsum board vibration. Then, the vibration passes through stud and gypsum board as resonation. And radiation as noise from surface of gypsum board into adjacent room. At this moment, according to thickness, placement and cross-section of stud, noise transmission ratio changes. Thicker stud has better sound insulation performance. Studs are apart from each other, has better sound insulation performance. But, single stud structure has restriction of thickness and arrange of studs. In this article, Sound insulation performance varies depending on the shape of the studs were studied.

• 한국재료학회지
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• 제10권8호
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• pp.564-568
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• 2000

Langmuir-Blodgett(LB) 법은 미래의 분자전자소자를 위한 가장 유력한 수단이며, 이러한 분자박막 소자는 그 성질이 분자는 배향에 영향을 박데 되므로 현재 새로운 물질을 이용하여 분자전자소자의 제작에 있어 관심을 모으고 있다. 본 연구에서는 (N-docosyl quinolinium)-TCNQ(1:2) 전하 이동 착물 LB 막의 분자 배향을 UV/vis 편광흡수 스펙트럼과 FT-IR transmission 및 reflection-absorption 스펙트럼의 흡수강도를 비교하여 정량적으로 평가하였다. 그 결과 TCNQ의 transition dipole moment의 각은 약 56~58。 였으며, 알킬 고리의 경사각은 약 11.1~13。였다. 제작된 Z-형 LB 막의 표면은 고압에서 중앙 높이 차가 3~4$\AA$으로 평탄하였다.

• 한국자동차공학회논문집
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• 제16권5호
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• pp.164-170
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• 2008

A typical clutch system for automotive manual transmissions transfers hydraulic pressure generated by driver's pedal manipulation to the clutch diaphragm spring. The foot effort history during the period of push is different than the period of the clutch pedal's return. The effort or load difference is called clutch foot effort hysteresis. It is known that the hysteresis is caused by friction. The frictional force and moment are produced between various component contact points such as between the rubber seal and the inner wall inside the hydraulic cylinder and between the diaphragm spring and the pressure plate, etc. Understanding the clutch pedal foot effort hysteresis is essential for a clutch release system design and analysis. The dynamic model for a clutch release system is developed for the foot effort hysteresis prediction and a simulation analysis is performed to propose a tool for analysing a clutch system.