• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.510-513
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• 2003

Our Zn diffusion into n-type $GaAs_{0.40}P_{0.60}$ used ampoule-tube method to increase IV. N-type epitaxial wafers were preferred by $H_2SO_4$-based pre-treatment. $SiO_2$ thin film was deposited by PECVD for some wafers. Diffusion times and diffusion temperatures respectability are 1, 2, 3 hr and 775, $805^{\circ}C$. LED chips were fabricated by the diffused wafers at Fab. The peak wavelength of all chips showed about $625{\sim}650\;nm$ and red color. The highest IV is about 270 mcd at the diffusion condition of $775^{\circ}C$, 3h for the wafers which didn't deposit $SiO_2$ thin films. Also, the longer diffusion time is the higher IV for the wafers which deposit $SiO_2$ thin films.

• 한국전기전자재료학회논문지
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• 제30권6호
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• pp.372-375
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• 2017

ZnO thin films were deposited by RF magnetron sputtering and then diffused by using an As source in the ampouletube. Also, the ZnO p-n homojunction was made by using As-doped ZnO thin films, and its properties were analyzed. After the As doping, the surface roughness increased, the crystal quality deteriorated, and the full width at half maximum was increased. The As-doped ZnO thin films showed typical p-type properties, and their resistivity was as low as $2.19{\times}10^{-3}{\Omega}cm$, probably because of the in-diffusion from an external As source and out-diffusion from the GaAs substrate. Also, the ZnO p-n junction displayed the typical rectification properties of a p-n junction. Therefore, the As diffusion method is effective for obtaining ZnO films with p-type properties.

• 한국세라믹학회지
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• 제36권6호
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• pp.583-589
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• 1999

In the fabrication of ceramic chip couples for high frequency application such as the mobile communication equipment the formation of electrode lines and Ag diffusion were investigated with heat treatment conditions for removing organic binders. The deformation and densification of the electrode line greatly depended on the binder burnout process due to the overlapped temperature zone near 400$^{\circ}C$ of the binder dissociation and the solid phase sintering of the silver electrode. Ag ions were diffused into the glass ceramic substrate. The Ag diffusion was led by the glassy phase containing Pb ions rather than by the crystalline phase containing Ca ions. The fact suggests that the Ag diffusion could be controlled by managing the composition of the glass ceramic substrate.

• Nuclear Engineering and Technology
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• 제43권6호
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• pp.477-488
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• 2011

A formulation is proposed for modelling the process of intra-granular diffusion of fission gas during irradiation of $UO_2$ under both normal operating conditions and power transients. The concept represents a simple extension of the formulation of Speight, including an estimation of the contribution of bubble motion to fission gas diffusion. The resulting equation is formally identical to the diffusion equation adopted in most models that are based on the formulation of Speight, therefore retaining the advantages in terms of simplicity of the mathematical-numerical treatment and allowing application in integral fuel performance codes. The development of the new model proposed here relies on results obtained by means of molecular dynamics simulations as well as finite element computations. The formulation is proposed for incorporation in the TRANSURANUS fuel performance code.

• 열처리공학회지
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• 제3권3호
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• pp.5-12
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• 1990

This study has been conducted to establish the carburizing characteristics of low carbon alloy steels with varying amount of Ni element gas-carburized for 2 hours at $930^{\circ}C$ in an atmosphere of 94% $N_2$-6% $C_3H_8$ gas mixture with some changes in gas pressure passing through the diffusion plate in the fluidized-bed furnace. The results obtained from the experiment are as follows : (1) Optical micrograph has shown that the carburized layer consists of retained austenite and plate martensite and that retained austenite increases as the pressure of gas mixture passing through the diffusion plate as well as Ni content increase. (2) Chemical analysis has shown that carbon potential increases and carburizability is also improved due to a less degree of fluidization as the pressures of gas mixtures passing through the diffusion plate increase, resulting in, however, a severe formation of soot, and the gas pressure is necessarily regulated. (3) It has been revealed that carbon concentration hardness values at a given distance measured from the surface within the carburized case. Increase with increasing the pressure of gas mixtures passing through the diffusion plate and decrease with increasing Ni content. (4) The effective case depth has been shown to almost linearly increase as the pressure of gas mixtures passing through the diffusion plate is increased and to decrease with increasing Ni content.

• 한국기계가공학회지
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• 제20권2호
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• pp.51-57
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• 2021

The quality of the ceramic sintered coating on a metal surface through laser surface treatment is affected by the laser irradiation pattern. Depending on the laser irradiation pattern, the amount of residual stress and heat applied or accumulated on the surface increases or decreases, affecting the thickness attained in the ceramic sintering area. When the heat energy accumulated in the sintering area is high, the ceramic and the metal alloy melt and sufficiently mix to form a homogeneous and thick bonding interface. In this study, the thermal energy accumulation in the region sintered with zirconia was controlled using four types of laser processing patterns. The thickness of the diffusion region is analyzed by laser-induced breakdown spectroscopy of Mg-ZrO2 generated by laser sintering zirconia powder on the magnesium alloy surface. On the basis of the analysis of the Mg and Zr present in the sintered region through LIBS, the effect of the irradiation pattern on the sintering quality is confirmed by comparing and analyzing the heat and mass transfer tendency of the diffusion layer and the degree of diffusion according to the irradiation pattern. The derived diffusion coefficients differed by up to 9.8 times for each laser scanning pattern.

• 열처리공학회지
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• 제1권1호
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• pp.8-12
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• 1988

This study has been carried out to evaluate gaseous nitrocarburizing treatment undertaken for pure iron at $570^{\circ}C$ in an atmosphere containing 50% endothermic gas, generated from natural gas, and 50% ammonia. The results obtained from the experiment are as follows ; 1) The microstructure of gaseous nitrocarburized pure iron consists of the compound layer on the surface and the diffusion zone beneath it. The compound layer progresses uniformly into ferrite with a thickness of $20{\mu}$ obtained after treating for 3 hours. 2) Chemical analysis has shown that the compound layer has a C/N ratio of 0.19 and that the average combined interstitial content of the compound layer is about 30 atomic percent, which is close to the lower limit of the ${\varepsilon}$-carbonitride phase field in Fe-C-N phase diagram. 3) X-ray diffraction analysis has revealed that the compound layer consists mainly of the c.p.h. phase, ${\varepsilon}-Fe_3$(C.N) and a small amount of $Fe_4N$ and traces of ferrite are also present in the compound layer. 4) The microhardness of the compound layer is about 600 V.H.N and shows a relatively sharp fall-off at the compound layer/diffusion zome interface. 5) The average actual degree of ammonia dissociation is calculated to be 27% for a gaseous nitrocarburizing treatment carried out at $570^{\circ}C$.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 1998년도 특별강연 및 추계학술발표 개요집
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• pp.260-261
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• 1998

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 1996년도 특별강연 및 춘계학술발표 개요집
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• pp.38-40
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• 1996

• 한국막학회:학술대회논문집
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• 한국막학회 2000년도 춘계 총회 및 학술발표회
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• pp.13-20
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• 2000