• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.05b
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• pp.135-141
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• 2000

The physical, electrical and piezoresitive characteristics of CrN(chromiun nitride) thin-films on silicon substrates have been investigated for use as strain gauges. The thin-film depositions have been carried out by OC reactive magnetron sputtering in an argon-nitrogen atmosphere(Ar-(5~25 %)$N_2$). The deposited CrN thin-films with thickness of $3500{\AA}$ and annealing conditions($300^{\circ}C$, 48 hr) in Ar-10 % $N_2$ deposition atmosphere have been selected as the ideal piezoresistive material for the strain gauges. Under optimum conditions, the CrN thin-films for the strain gauges is obtained a high electrical resistivity, $\rho=1147.65\;{\mu}{\Omega}cm$, a low temperature coefficient of resistance, TCR=-186 ppm/$^{\circ}C$ and a high temporal stability with a good longitudinal gauge factor, GF=11.17.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.4
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• pp.293-297
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• 1998

The influence of ion implantation on surface properties of polymers was studied. We investigated microhardness, friction, wear and wettablility of polyimide. Energies of 50, 200keV were used with doses range from $1{\times}10^{13} to 1{\times}10^{16} [ions/cm^2]$. The implanted ion species were B, N and Ar. The microhardness of polyimide was increased after implantation for doses of $1{\times}10^{15}\; [ions/cm^2]$. A reduction of the friction coefficient was in most case correlated with a reduction of wear. The contact angles of water for $B^+,N^+$ implanted polyimide decreased from $76^{\circ}C$ to zero, as the fluencies increased at energies of 50 and 200 KeV. However, the contact angle of Ar ion implanted polyimide did not change under ambient room conditions even if the time elapsed. SEM measurement was performed to characterize the modified surface layer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.934-941
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• 2000

We measured the electron transport coefficients, the electron drift velocity W and the longitudinal diffusion coefficient $D_{L}$ in the 0.526% and 5.05% $C_{3}F_{8}$-Ar mixtures over the E/N range from 0.01 Td to 100 Td by the double shutter drift tube, and compared the measured results by Hunter et al. with those. We determined the inelastic collision cross sections for the $C_{3}F_{8}$ molecule by the comparison of the present measurements and the calculation of electron transport coefficients in the $C_{3}F_{8}$-Ar mixtures by using a multi-term Boltzmann equation analysis.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.3
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• pp.259-263
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• 2005

The changes in secondary electron emission coefficient(${\gamma}$) and work function($\Phi$$_{\omega}$) have been studied on the surface of MgO protective layer aster plasma(Ar. $O_2$) treatment using ${\gamma}$-focused ion beam (${\gamma}$-FIB) system. The values of ${\gamma}$ varied as follows: $O_2$-treated MgO > Ar-treated MgO > Non-treated MgO, and the work functions varied in the reverse order. The result indicates that both the physical etching and the chemical reaction of $O_2$-plasma removed the contaminating materials from the surface of MgO.

• Fire Science and Engineering
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• v.18 no.3
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• pp.9-17
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• 2004

The values of physical properties of the inert gases of Ar, $N_2$, $CO_2$ were calculated by the empirical equations. The regression coefficients were obtained by the experimental data and the resulting calculated values. For the empirical equation with a lower regression coefficient, a new correlation was suggested. At an atmosphere pressure, the empirical equation was confirmed by the experimental values for the viscosity, density, saturated pressure, and surface tension of Ar, $N_2$, $CO_2$. The correlation coefficients of the empirical equations proposed in this work was higher than 0.99.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.213-216
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• 2001

Etching behaviors of ferroelectric YMn $O_3$ thin films were studied by an inductively coupled plasma (ICP). Etch characteristic on ferroelectric YMn $O_3$ thin film have been investigated in terms of etch rate, selectivity and etch profile. The maximum etch rate of YMn $O_3$ thin film is 300 $\AA$/min at Ar/C $l_2$ of 2/8, RF power of 800W, dc bias voltage of 200V, chamber pressure of 15mTorr and substrate temperature of 3$0^{\circ}C$. Addition of C $F_4$ gas decrease the etch rate of YMn $O_3$ thin film. From the results of XPS analysis, Y $F_{X}$ compunds were found on the surface of YMn $O_3$ thin film which is etched in Ar/C1/C $F_4$ plasma. The etch profile of YMn $O_3$ film is improved by addition of C $F_4$ gas into the Ar/C $l_2$ plasma. These results suggest that fluoride yttrium acts as a sidewall passivants which reduce the sticking coefficient of chlorine on YMn $O_3$.>.

• Journal of the Korean institute of surface engineering
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• v.55 no.6
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• pp.376-382
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• 2022

Yb₂Si₂O₇ has a coefficient of thermal expansion similar to that of the base material of SiC and has excellent corrosion resistance in a high-temperature oxidizing atmosphere including water vapor, so it is being studied as one of the materials for environmental barrier coatings (EBCs). In this study, Yb₂Si₂O₇ powder granule is deposited using atmospheric plasma spraying (APS) with different Ar/He ratios. Phase formation and microstructural characteristics are investigated with the coated specimens. In the coating layer, the crystallinity decreased, and the amorphous content increased from an increase in the ratio of Ar. In addition, the various types of particles involved by local volatilization of Si according to the Ar/He ratios were identified.

• Annals of Surgical Treatment and Research
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• v.95 no.6
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• pp.297-302
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• 2018

Purpose: Increased robotic surgery is attended by increased reports of complications, largely due to limited operative view and lack of tactile sense. These kinds of obstacles, which seldom occur in open surgery, are challenging for beginner surgeons. To enhance robotic surgery safety, we created an augmented reality (AR) model of the organs around the thyroid glands, and tested the AR model applicability in robotic thyroidectomy. Methods: We created AR images of the thyroid gland, common carotid arteries, trachea, and esophagus using preoperative CT images of a thyroid carcinoma patient. For a preliminary test, we overlaid the AR images on a 3-dimensional printed model at five different angles and evaluated its accuracy using Dice similarity coefficient. We then overlaid the AR images on the real-time operative images during robotic thyroidectomy. Results: The Dice similarity coefficients ranged from 0.984 to 0.9908, and the mean of the five different angles was 0.987. During the entire process of robotic thyroidectomy, the AR images were successfully overlaid on the real-time operative images using manual registration. Conclusion: We successfully demonstrated the use of AR on the operative field during robotic thyroidectomy. Although there are currently limitations, the use of AR in robotic surgery will become more practical as the technology advances and may contribute to the enhancement of surgical safety.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1540-1541
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• 2011

We calculated the electron transport coefficients in $H_2$+Ar gas calculated E/N values 0.01 ~ 1 Td by the Boltzmann equation method. This study gained the values of the electron swarm parameters such as the electron drift velocity and the transverse diffusion coefficients for $H_2$+Ar gas at a range of E/N. The transport coefficient W and Dt/u have been calculated in mixtures of 0.5% and 4% hydrogen in argon. All values were made at 293 K.

• Communications for Statistical Applications and Methods
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• v.8 no.3
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• pp.777-786
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• 2001

The autoregressive models have been used to describe a wade variety of time series. Then the problem of determining the order in the times series model is very important in data analysis. We consider the Bayesian approach for finding the order of autoregressive(AR) error models using the latent variable which is motivated by Tanner and Wong(1987). The latent variables are combined with the coefficient parameters and the sequential steps are proposed to set up the prior of the latent variables. Markov chain Monte Carlo method(Gibbs sampler and Metropolis-Hasting algorithm) is used in order to overcome the difficulties of Bayesian computations. Three examples including AR(3) error model are presented to illustrate our proposed methodology.