• 한국과학교육학회지
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• 제31권6호
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• pp.848-863
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• 2011

본 연구는 기본물리상수의 교육적 활용 실태를 탐색하기 위하여 문헌연구를 통해 기본물리상수를 구성하는 구성요소로 수치, 크기, 단위, 차원, 탄생배경 및 측정실험, 물리적 의미를 제안하고, 각각의 측면에서 고등학교 물리 교과서의 내용을 분석하였다. 나아가 계층적 분석과정(Analytic Hierarchy Process, AHP)을 통해 각각의 기본물리상수 별로 강조되는 구성요소의 상대적 중요도를 결정하였다. 이를 바탕으로 기본물리상수에 대한 고등학교 물리교사들의 인식수준을 알아보기 위해 검사도구를 개발하여 서울, 경기, 인천 소재 고등학교 물리교사 124명을 대상으로 기본물리상수에 대한 인식 수준과 교수-학습에의 적용에 대한 인식을 설문조사하였다. 또한, 설문 내용에 대한 심층적인 이해와 구체적인 교수 전략을 알아보기 위하여 교사 6명과의 면담을 시행하였다. 면담 결과 교사들의 기본물리상수에 대한 인식과 구체적인 교육적 활용 실태를 알 수 있었다.

• 전기의세계
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• 제24권1호
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• pp.29-42
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• 1975

In this paper, the electrical angle between two winding axes in the stator of the capacitor motor is put optional angle, deviding the space harmonics in its magnetic field of two windings and the leakage flux into the forward revolving field and the backward one by the revolving-field theory, its equivalent circuit which consider mutual induction between two windings is depicted. In the depicted equivalent circuit, the rotor resistance for the fundamental flux is devided into the resistance for the rotor bar and endring, and the rotor leakage reactance for the fundamental is devided into the skew leadage reactance and the other, and each circuit constants for each harmonics is expressed in terms of the circuit constants for the fundamental, so it mades easy to determine the characteristics for the capacitor motor. As the circuit constant ratios to the magnetizing reactance of the fundamental are used, motors which have same circuit constant ratios should be resembled in their characteristics.

• 전기의세계
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• 제26권4호
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• pp.41-53
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• 1977

With the equivalent series circuit analyzed aby revolving field theory and drawn by using the equivalent circuit constant ratios in capacitor motor with windings not in quadrature having space harmonics in its magnetic field (the above ratios are the equivalent circuit constants for the fundamental flux to the magnetizing reactance of the circuit), the equation for the alternating torque with twice line freequency in the motor is directly derived, and the alternating torque is measured with the self-made stator vibration angle amplitude measuring apparatus that is composed of a pickup, filter, photoelectric pickoff etc. The measured values satisfactorily compared with computed values. The properties of the alternating torque characteristics for respective harmonic fluxes and the r5esultant alternating torque characteristic, the effects of the alternating torque characteristics for respective harmonic fluxes on the resultant alternating torque characteristic, the effects of the variation in the motor constants and the equivalent circuit constant ratios for the fundamental flux on the alternating torque characteristics for respective harmonic fluxes and the resultant alternating torque characteristic, are made clear, applying the equation. There exist the optimum values of the motor constants and the equivalent circuit constant ratios for the fundamental flux for decreasing the alternating torque, and the value could be determined in design by the method presented in this paper.

• 한국광학회지
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• 제30권4호
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• pp.133-141
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• 2019

기본상수를 이용한 국제단위계 개정이 2018년 11월에 개최된 제26차 국제도량형총회에서 채택되었다. 국제단위계에 속한 4개의 기본단위(킬로그램, 암페어, 켈빈, 몰)가 각각 그 값이 고정된 플랑크 상수 h, 기본 전하 e, 볼츠만 상수 k, 아보가드로 상수 $N_A$를 기반으로 재정의되었다. 이 논문에서는 키블 저울을 이용하여 플랑크 상수로부터 킬로그램을 재정의한 원리를 설명한다. 개정된 국제단위계는 2019년 5월 20일부터 발효된다.

• Journal of applied mathematics & informatics
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• 제12권1_2호
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• pp.183-198
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• 2003

We highlight the alternative presentation of the Cauchy-Riemann conditions for the analyticity of a complex variable function and consider plane equilibrium problem for an elastic transversely isotropic layer, in finite deformation. We state the fundamental problems and consider traction boundary value problem, as an example of fundamental problem-one. A simple solution of“Lame's problem”for an infinite layer is obtained. The profile of the deformed contour is given; and this depends on the order of the term used in the power series specification for the complex potential and on the material constants of the medium.

• 전기의세계
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• 제22권3호
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• pp.25-34
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• 1973

In this paper, the characteristics of a single phase induction motor which is considered the space harmonic flux by the double revolving field theory is analysed. As the rotor resistance for the fundamental flux is separated from the resistance for the rotor bar and end-ring, and the rotor leakage reactnace is separated from the skew leakage reactance and the other, so the circuit constants for the space harmonic flux is expressed by the circuit constants for the fundamentals. As the ratio of the circuit constants for the magnetizing reactance is used, the generalized equivalent circuit is made up. the characteristic equation which is able to analysis the subdivided characteristics by the above circuit is induced. The ratio of the circuit constants and the skew angle being changed, the variations of the torque-speed characteristics for the fundamentals and harmonics is examined by this equation.

• Structural Engineering and Mechanics
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• 제58권2호
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• pp.347-378
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• 2016

Within the scope of the plane-strain state, by utilizing the three-dimensional linearized theory of elastic waves in initially stressed piezoelectric and elastic materials, Lamb wave propagation and the influence of the initial stresses on this propagation in a sandwich plate with pre-stressed piezoelectric face and pre-stressed metal elastic core layers are investigated. Dispersion equations are derived for the extensional and flexural Lamb waves and, as a result of numerical solution to these equations, the corresponding dispersion curves for the first (fundamental) and second modes are constructed. Concrete numerical results are obtained for the cases where the face layers' materials are PZT-2 or PZT-6B, but the material of the middle layer is Steel (St) or Aluminum (Al). Sandwich plates PZT-2/St/PZT-2, PZT-2/Al/PZT-2, PZT-6B/St/PZT-6B and PZT-6B/Al/PZT-6B are examined and the influence of the problem parameters such as piezoelectric and dielectric constants, layer thickness ratios and third order elastic constants of the St and Al on the effects of the initial stresses on the wave propagation velocity is studied.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 Proceedings of the Korea Automatic Control Conference, 11th (KACC); Pohang, Korea; 24-26 Oct. 1996
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• pp.334-337
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• 1996

This is a paper intended for initial stage of vehicle modeling and design. The needs to determine a variety of vehicle suspension parameters required for initial design has been difficult and time-consuming task. In order to facilitate a concise and efficient presentation of initial vehicle design procedure, this paper uses a mathematical model and physical geometry. Vehicle model consists of dimensions, inertias and mechanical constants. These vehicle model parameters divided into several categories : basic parameters, coefficients and constants, design specification, spring and damper, bush stiffness, stabilizer bar, suspension geometry, tire, and vehicle weights of various design condition. This paper uses a vehicle design fundamental (VDF) program running under Windows 95 graphical interface. The features of VDF will be briefly outlined in this paper.

• 한국농공학회지
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• 제26권3호
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• pp.90-98
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• 1984

In this paper, the anthor made a basic study of the storage function model and examined several constants in applying the storage function model to flood run-off analysis by dealing with the data in the Supyung and Hoyng Syung watershed, the applicabilities of the storage function model are examined by searching this optimum model parameters in two watersheds. The results are summarized as follows, 1) The optimum values of the exponential constants, P, in the storage function model showed to be 0.77 to 0.87 in two watersheds observed, therefore it was confirmed that the storage fumction model was approaching to the surface runoff model. 2) It was confirmed that the interval of variation of the storage constant, K, Showed to be larger than that of the exponential constant, p. 3) Relative erros in the discharge obtained by using the storage function model and the SDFP mothod showed to be 20 and 17 percent respectively to the observed discharge, therefore it was confirmed that the applicability of the storage function model using the SDFP method are excellent for runoff analysis. 4) A simple method is proposed for estimating the lag time in the storage function model.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.181-185
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• 2001

This paper deals with the dynamic stability of a disc brake pad taking into account of its shear deformation and rotary inertia. A brake pad can be modeled as a beam like model subjected to distributed friction forces and having two translational springs. The study of this model is intended to provide a fundamental understanding of dynamic stability of drum brake pad. Governing equations of motion are derived from extended Hamilton's principle and their corresponding numerical solutions are obtained by applying the finite element formulation. The critical distributed friction force and the instability types are investigated bt changing two translational spring constants, rotary inertia parameter and shear deformation parameter. Also, the changes of eigen-frequencies of a beam determining instability types are investigated for various combinations of two translational spring constants.