• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1920-1921
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• 2007

본 논문에서는 나선주사 영상에서 발생하는 off-resonance 현상에 의한 영상의 번짐을 보정하는 새로운 알고리즘을 제안하였다. 공간상에서의 inhomogeneity와 chemical-shift 현상으로 생기는 off-resonance 효과는 공간의 자장의 세기에 비례한다. 현재 사용되고 있는 보정 방법에서의 절차를 간소화 하고 보다 효과적인 보정 알고리즘을 적용함으로써 보다 나은 Spiral scan 영상을 얻고자 하였다.

• Bulletin of the Korean Chemical Society
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• v.21 no.7
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• pp.712-714
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• 2000

Non-Lorentyian resonance is predicted to occur in two-photon photoabsorption processes due to the detuning off the intermediate levels. This type of non-Lorentzian resonance is distinct from the asymmetric resonance resulting from the effects of q uantum interference between competing indistinguishable dynamic pathways. The product distributions are shown to be constant near this type of resonance.

• Journal of KSNVE
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• v.10 no.6
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• pp.1041-1047
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• 2000

The main objectives of this study are to examine the random response of a vibration absorber system with autoparametric coupling in the neighborhood of internal resonance by Gaussian closure and to compare the results with those obtained by Monte Carlo simulation. The numerical simulation is found to support the main features of the nonlinear modal interaction in the neighborhood of internal resonance conditions. While the Gaussian closure exhibits regions of multiple solutions in the neighborhood of internal resonance, the numerical simulation gives only one solution depending on the assigned initial conditions. The on-off intermittency phenomena of the cantilever mode is observed in the Monte Carlo simulation over a small range of parameter.

• Ocean Systems Engineering
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• v.2 no.4
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• pp.297-314
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• 2012

Power-take-off through inner dynamic system inside a floating buoy is suggested. The power take-off system is characterized by mass, stiffness, and damping and generates power through the relative heave motion between the buoy and inner mass (magnet or amateur). A systematic hydrodynamic theory is developed for the suggested WEC and the developed theory is illustrated by a case study. A vertical truncated cylinder is selected as a buoy and the optimal condition of the inner dynamic system for maximum PTO (power take off) through double resonance for the given wave condition is systematically investigated. Through the case study, it is seen that the maximum power can actually be obtained at the optimal spring and damper condition, as predicted by the developed WEC theory. However, the band-width of high performance region is not necessarily the greatest at the optimal (maximum-power-take-off) condition, so it has to be taken into consideration in the actual design of the WEC.

• Proceedings of the KSMRM Conference
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• 2006.11a
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• pp.68-68
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• 2006

• Proceedings of the Optical Society of Korea Conference
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• 2007.02a
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• pp.355-356
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• 2007

• Proceedings of the KSMRM Conference
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• 2008.04a
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• pp.23-29
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• 2008

• Journal of the Korean Magnetic Resonance Society
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• v.17 no.2
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• pp.92-97
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• 2013

We study the electron spin resonance line-width (ESRLW) of $Fe^{3+}$ in crystalline $LiNbO_3$ ; the ESRLW is obtained using the projection operator method (POM) developed by Argyres and Sigel. The ESRLW is calculated to be axially symmetric about the c-axis and is analyzed by the spin Hamiltonian with an isotopic g factor at a frequency of 9.5 GHz. The ESRLW increases exponentially as the temperature increases, and the ESRLW is almost constant in the high-temperature region (T>8000 K). This kind of temperature dependence of the ESRLW indicates a motional narrowing of the spectrum when $Fe^{3+}$ ions substitute the $Nb^{5+}$ ions in an off-center position. It is clear from this feature that there are two different regions in the graph of the temperature dependence of the ESRLW.

• Journal of Sensor Science and Technology
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• v.29 no.1
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• pp.45-50
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• 2020

Magnetoelectric (ME) composites were designed using the PMN-PZT single crystal and Ni foils; the properties and magnetic-field sensitivities of ME composites with different piezoelectric vibration modes (i.e., 31, 32, and 36 modes that depend on the crystal orientation of the single crystal) were compared. In the off-resonance condition, the ME coupling properties of the ME composites with the 32 and 36 piezoelectric vibration modes were better than those of the ME composites with the 31 piezoelectric vibration mode. However, in the resonance condition, the ME coupling properties of the ME composites were almost similar, irrespective of the piezoelectric vibration mode. Additionally, in the off-resonance condition (at 1 kHz), the magnetic-field sensitivity of the ME composites with the 36 piezoelectric vibration mode was up to 2 nT and those of the ME composites with the 31 and 32 piezoelectric vibration modes were up to 5 nT. These magnetic-field sensitivities are similar to those offered by conventional high-sensitivity magnetic-field sensors; the potential of the proposed sensor to replace costly and bulky high-sensitivity magnetic field sensors is significant.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.343-343
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• 2008

Newly designed structure of a thin ultrasonic rotary motor was proposed. Thin brass plate was used as a cross shaped vibrator and eight ceramic plates were attached on the upper and bottom sides of the brass plate as in Figure 1. The thin type ultrasonic motor has the structure adherent piezoelectric ceramic on the top and bottom surface of the thin elastic body. The direction of polarization is decided so as to occur the elliptical displacement in regular sequence at touch point A, B, C and D of stator contacted with rotor. By applying two electric fields which have 90 degree phase difference on the ceramics, each contact points make rotational displacements as in figure 2. Finite element analysis program ATILA was used to find the optimal size of the stator. As a result of the simulation, elliptical displacements of the tips were obtained at off-resonance frequencies. The maximum displacements of the contact tips were obtained at the length of 16[mm], width of 6[mm] and thickness of 0.4[mm]. Changes of the resonance frequencies were inversely proportional to the length of ceramic and proportional to the width of ceramic. Elliptical motions of the contact tips. of the stator were consistently obtained at off resonance frequencies. From a prototype motor, speed of 600[rpm] was obtained at 20[Vrms].