• 대한의용생체공학회:의공학회지
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• 제2권1호
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• pp.3-14
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• 1981

A theoretical investigation of the origin of the spontaneous firing in the squid axon was done with a mathmatical computer modelling based on the Hodgkin-Huxley equation. It is strongly believed that the existence of calcium ions in the membrane is essential to cause firing. The results of the computer simulation of the modelling indicate that the sites of calcium ions in the membrane might be near the potassium channel and the leakage channel plays an important role in the firing. The orientation of the future research project was suggested. And also, a theoretical investigation of the origin of the firing in the propagating action potential was done in the same way.

• 대한기계학회논문집A
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• 제20권5호
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• pp.1363-1371
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• 1996

This paper presents the design, fabrication, and testing of polysilicon electrostatic microactuators that resonate in the direction parallel to the silicon susbstrates. A set of six different designs has been developed using a theoretical model and design formulae developed for the mocroactuators. Microactuator prototypes are fabricated from a 2.1 $\mu{m}$-thick LPCVD polysilicon film, using a 4-mask surface-micromachining process. The prototypes are tested under a d.c. bias voltage of 45V with an a.c. drive voltage amplitude of 20 v.Measured resorant frequencies are in the ranges of 40-60 kHz, showing a good agreement to their theoretical estimates within error bounds of .$\pm$.5%. Important issues inthe design and microfabrication of the microactuators are discussed, together with potential applicaitons of the key technology involved.

• 한국소음진동공학회논문집
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• 제13권10호
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• pp.751-759
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• 2003

The theoretical method is developed to investigate the vibration characteristics of the sloshing and bulging mode for the circular cylindrical storage tank with an annular plate on free surface. The cylindrical tank is filled with an inviscid and incompressible liquid. The liquid domain is limited by a rigid cylindrical surface and a rigid flat bottom. As the effect of free surface waves Is taken into account in the analysis, the bulging and sloshing modes are studied. The solution for the velocity potential of liquid movement is assumed as a suitable harmonic function that satisfies Laplace equation and the relevant boundary conditions. The Rayleigh-Ritz method is used to derive the frequency equation of the cylindrical tank. The effect of Inner-to-outer radius ratio and thickness of annular plate and liquid volume on vibration characteristics of storage tank is studied. The finite element analysis is performed to demonstrate the validity of present theoretical method.

• 대한화학회지
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• 제22권6호
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• pp.403-411
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• 1978

Collagen의 model compound인 poly(Gly-Pro-Pro)의 수화에 관해서 empirical ppotential energy 함수를 사용하여 이론적으로 연구하였다. 물 분자와 model compound 간의 상호작용 energy를 최소화시켜서 물 분자들의 위치와 결합 energies를 계산하였다. 다음에는 일차수화층에 물이 붙음으로써 생기는 안정화 energy를 계산하고, 전체 안정화에 기여하는 여러 energy components의 기여도에 대해 논의하였다.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2003년도 하계학술연구발표회 및 한.일 공동심포지엄
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• pp.140-141
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• 2003

Recently, a large magneto-caloric effect (MCE) in perovskite materials has generated growing interests among scientists and manufacturers, because of its assessable and practical potential for the field of magnetic refrigeration. Nevertheless, further efforts of seeking a proper material that has a large magnetic-entropy change (ΔS$\sub$M/) or a large adiabatic temperature change (ΔT$\sub$ad/), i.e. a large MCE, in a vast variety of temperatures have been extensively devoted, but no theoretical treatments are satisfactorily made.

• 대한기계학회논문집A
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• 제28권3호
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• pp.274-280
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• 2004

This paper presents the analysis fur the radial vibration characteristics of cylindrical piezoelectric transducers. Taking into account the piezoelectric anisotropy, the differential equations of piezoelectric radial motion have been derived in terms of radial displacement and electric potential. Applying mechanical and electric boundary conditions has yielded a characteristic equation for radial vibration. Numerical analysis also has been carried out by using the finite element method. Theoretical calculations of the fundamental natural frequency have been compared with the experimental observations for transducers of several sizes. Comparison with the previous report of theoretical analysis simplifying the piezoelectric anisotropy into isotropy concludes that isotropic analysis is a reasonable process to predict the vibration characteristics of piezoelectric transducers.

• 한국표면공학회지
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• 제12권3호
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• pp.161-166
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• 1979

Theoretical and practical aspects are investigated for electrochemical behavious, plating processes and the structures of electrodeposit of Pb-Sn binary alloy plating through numerous literatures in this report. The anodic and cathodic electrode reaction mechanisms of Pb and Sn could co-deposit and make Pb-Sn alloy deposit from the results of cathode current density-cathode potential curves of Pb, Sn and Pb-Sn alloys in fluoborate solutions. The compositions of the best alloy plating solutions are obtained for the purpose of bearing, anticorrosion and solder plating. In general, the casting anodes of Pb-Sn alloys are used, but separated anodes of Pb and Sn pure metal are used in order to obtain the fine compositions of Pb-Sn alloy deposits. The electrodeposits of Pb-Sn alloy are in nonequilibrium state and saturated solid solutions. Thus, ${\beta}$-phase (Sn-phase) is precipitated by heat treatment. The texture and structure of the electrodeposit are associated with the surface energies of deposit lattice planes and with the cathode polarization. The electrodeposit of Pb-Sn alloy is shown as lamellar structure.

• International Journal of Naval Architecture and Ocean Engineering
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• 제7권5호
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• pp.785-794
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• 2015

To obtain low resistance and high efficiency energy-saving ship, minimum total resistance hull form design method is studied based on potential flow theory of wave-making resistance and considering the effects of tail viscous separation. With the sum of wave resistance and viscous resistance as objective functions and the parameters of B-Spline function as design variables, mathematical models are built using Nonlinear Programming Method (NLP) ensuring the basic limit of displacement and considering rear viscous separation. We develop ship lines optimization procedures with intellectual property rights. Series60 is used as parent ship in optimization design to obtain improved ship (Series60-1) theoretically. Then drag tests for the improved ship (Series60-1) is made to get the actual minimum total resistance hull form.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.964-968
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• 2008

Infrared thermography using high-speed infrared camera has been recognized as a powerful method for various potential applications, such as nondestructive inspection, failure analysis, stress analysis, and medical fields, due to non-contact, high-speed, and high spatial resolution at various temperature ranges. In this investigation, damage evolution due to generation of hot spots on railway brake disc was investigated using the infrared thermography method. A high-speed infrared camera was used to measure the surface temperature of brake disc as well as for in-situ monitoring of hot spot evolution. From the thermographic images, the observed hot spots and thermal damage of railway brake disc during braking operation were qualitatively analyzed. Moreover, in this investigation, the previous experimental and theoretical studies on hot spots phenomenon were reviewed, and the current experimental results were introduced and compared with theoretical prediction.

• 대한기계학회논문집B
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• 제29권1호
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• pp.131-138
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• 2005

Thermo-osmosis of liquids in a microscale channel is investigated by theoretical and simulation study. From the basic set of conservation equations, the temperature and velocity distributions are derived in the function of the given temperatures and pressure gradient. The pressure gradient for a given temperature gradient is then obtained by the molecular simulation. It is shown that the temperature gradient tangential to the surface induces the pressure gradient and thus the flow in the interfacial region between the liquid and channel surface. The thermo-osmotic flow is proportional to the applied temperature gradient, and the factor of proportionality depends on temperature and intermolecular potential. The origin and characteristics of the phenomenon are discussed in molecular details.