• Proceedings of the Korean Nuclear Society Conference
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• 2005.05a
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• pp.467-468
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• 2005

Low cycle fatigue test results of Type 316 stainless steel in $310^{\circ}C$ water environment can be summarized as follows. 1. Cyclic stress response of Type 316 stainless steel shows negative strain rate sensitivity, primary hardening and secondary hardening. 2. Fatigue life in $310^{\circ}C$ water environment was shorter than fatigue life in room temperature air environment. This was because of water environment and temperature effects.

• Applied Science and Convergence Technology
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• v.25 no.6
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• pp.154-157
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• 2016

The energy dispersion and magnetization of a modified magnetic dot are investigated numerically. The effects of additional electrostatic potential, magnetic field non-uniformity, and Zeeman spin splitting are studied. The modified magnetic quantum dot is a magnetically formed quantum structure that has different magnetic fields inside and outside of the dot. The additional electrostatic potential prohibits the ground-state angular momentum transition in the energy dispersion as a function of the magnetic field inside the dot, and provides oscillation of the magnetization as a function of the chemical potential energy. The magnetic field non-uniformity broadens the shape of the magnetization. The Zeeman spin splitting produces additional peaks on the magnetization.

• Journal of the Optical Society of Korea
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• v.1 no.2
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• pp.94-99
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• 1997

In this paper, we calculate the four coefficients for the quantum theory of multiwave mixing including a local-field correction resulting from dipole-dipole interactions. We make contact with the semiclassical calculations of probe absorption and four-wave-mixing coupling coefficients, and illustrate the effects of local field corrections on resonance-fluorescence and coupled-mode-fluorescence spectra. The method uses the hybrid quantum-Langevin-equation master-equation approach of An and Sargent.

• Journal of the Korean Vacuum Society
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• v.12 no.S1
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• pp.52-55
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• 2003

GaAs/AlGaAs quantum-wire (QWR) gain-coupled distributed-feedback (GC-DFB) lasers are fabricated and characterized Constant metalorganic chemical vapor deposition (MOCVD) growth is used to avoid grating overgrowth during the fabrication of DFB structures. Numerical calculation shows large gain anisotropy by optical feedback along the DFB directions near Bragg wavelength. DFB lasing via QWR active gratings is also experimentally achieved.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.3
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• pp.93-104
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• 1997

Steady-state I-V characteristics of a resonant tunneling diode (RTD) is calculated by numerical analysis using quantum liouville equation based on wigner function which is derived from density operator. Modifications to the conventional discrete model are made to calculate more accurate quantum correlations. It is pointed out that we must include inelastic processes and the resistivity of the contacting layers to get a much more credible potential which can be theoretically obtained from the simple screening theory. The effects of spatially-varying effective mass is also checked briefly.

• Proceedings of the Korean Nuclear Society Conference
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• 2005.10a
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• pp.1095-1096
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• 2005

• Journal of Radiation Industry
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• v.9 no.1
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• pp.1-7
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• 2015

The trend of x-ray image sensor has been evolved from an amorphous silicon sensor to a crystal silicon sensor. A crystal silicon X-ray sensor, meaning a X-ray CIS (CMOS image sensor), is consisted of three transistors (Trs), i.e., a Reset Transistor, a Source Follower and a Select Transistor, and a photodiode. They are highly sensitive to radiation exposure. As the frequency of exposure to radiation increases, the quality of the imaging device dramatically decreases. The most well known effects of a X-ray CIS due to the radiation damage are increments in the reset voltage and dark currents. In this study, a pixel array of a X-ray CIS was made of $20{\times}20pixels$ and this pixel array was exposed to a high radiation dose. The radiation source was Co-60 and the total radiation dose was increased from 1 to 9 kGy with a step of 1 kGy. We irradiated the small pixel array to get the increments data of the reset voltage and the dark currents. Also, we simulated the radiation effects of the pixel by MCNP (Monte Carlo N-Particle) simulation. From the comparison of actual data and simulation data, the most affected location could be determined and the cause of the increments of the reset voltage and dark current could be found.

• Proceedings of the IEEK Conference
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• 2001.06b
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• pp.177-180
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• 2001

The quantum effects in the channel of a $\delta$ -doped NMOSFET structures are investigated by solving Schrodinger and Poisson equations self-consistently. According to the scaling of MOSFET structures, electron distributions change by the strong energy quantization. However the presence of a low-doped epitaxial region produces a reduction of the electron effective field for a given charge sheet density and therefore, improves the electron effective mobility. We also focus the quantum-induced threshold voltage shifts, low-field electron effective mobility and gate-to-channel capacitance. The reported results give indications for the fabrication of ultra short MOSFET's.

• Korean Journal of Optics and Photonics
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• v.10 no.2
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• pp.114-119
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• 1999

In an interation-free measurement system with the polarization-based Mach-Zehnder interferometer structure, effects of two system imperfections, i.e., the system loss and the low quantum efficiency of photon detectors, on the system perfomance are analyzed, Although both the two system imperfections limit the maximal defection efficiency that can be achievable, we show that the quantum efficiency of photon detectors is less important when the system loss becomes small. In addition, for given system losses and quantum efficiencies, we derive the maximal detection efficiencies that can be achievable.

• Journal of Electrical Engineering and Technology
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• v.9 no.2
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• pp.649-654
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• 2014

In this paper, an analytical model for Surrounding Gate (SG) metal-oxide- semiconductor field effect transistors (MOSFETs) considering quantum effects is presented. To achieve this goal, we have used variational approach for solving the Poission and Schrodinger equations. This model is developed to provide an analytical expression for inversion charge distribution function for all regions of device operation. This expression is used to calculate the other important parameters like inversion charge density, threshold voltage, drain current and gate capacitance. The calculated expressions for the above parameters are simple and accurate. This paper also focuses on the gate tunneling issue associated with high dielectric constant. The validity of this model was checked for the devices with different dimensions and bias voltages. The calculated results are compared with the simulation results and they show good agreement.