• Journal of Magnetics
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• v.22 no.2
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• pp.315-325
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• 2017

Magnetically suspended sensitive gyroscopes (MSSGs) provide an interesting alternative for achieving precious attitude angular measurement. To effectively reduce the measurement error caused by the non-uniformity of the air-gap flux density in a MSSG, this paper proposes a novel compensation method based on measuring and modeling of the air-gap flux density. The angular velocity measurement principle and the structure of the MSSG are described, and then the characteristic of the air-gap flux density has been analyzed in detail. Next, to compensate the flux density distribution error and improve the measurement accuracy of the MSSG, a real-time compensation method based on the online measurement with hall probes is designed. The common issues caused by the non-uniformity of the air-gap flux density can be effectively resolved by the proposed method in high-precision magnetically suspended configurations. Comparative simulation results before and after compensation have verified the effectiveness and superiority of the proposed compensation method.

• Progress in Superconductivity and Cryogenics
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• v.15 no.3
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• pp.5-8
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• 2013

We have studied Hall effect for potassium (K)-doped $BaFe_2As_2$ superconducting thin films by analyzing the relation between the longitudinal resistivity (${\rho}_{xx}$) and the Hall resistivity (${\rho}_{xy}$). The thin films used in this study were fabricated on $Al_2O_3$ (000l) substrates by using an ex-situ pulsed laser deposition (PLD) technique under a high-vacuum condition of ~$10^{-6}$ Torr. The samples showed the high superconducting transition temperatures ($T_c$) of ~ 40 K. The ${\rho}_{xx}$ and the ${\rho}_{xy}$ for K-doped $BaFe_2As_2$ thin films were measured by using a physical property measurement system (PPMS) with a temperature sweep (T-sweep) mode at an applied current density of $100A/cm^2$ and at magnetic fields from 0 up to 9 T. We report the T-sweep results of the ${\rho}_{xx}$and the ${\rho}_{xy}$ to investigate Hall scaling behavior on the basis of the relation of ${\rho}_{xy}={A{\rho}_{xx}}^{\beta}$. The ${\beta}$ values are $3.0{\pm}0.2$ in the c-axis-oriented K-doped $BaFe_2As_2$ thin films, whereas the thin films with various oriented-directions like a polycrystal showed slightly lower ${\beta}$ than that of c-axis-oriented thin films. Interestingly, the ${\beta}$ value is decreased with increasing magnetic fields.

• 보존과학연구
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• s.36
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• pp.49-63
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• 2015

In this study, the annual and seasonal concentrations of aldehydes was measured using the active type and passive type method in the temporary exhibition hall and outdoor air. It was compared with the correlation between the methods according the comparison of methods to measured concentrations. As a results, the ${\Sigma}$ aldehydes in exhibition hall by the active type was higher than 6.4 times by passive type. The formaldehyde was exceeded standards in exhibition facilities of the Ministry of Environment. It was the highest concentrations in summer. Annual I/O ratio of formaldehyde was 5.4 and acetaldehyde was 1.9, it was confirmed that a large amount occurs in the temporary exhibition hall. The results of the correlation coefficient and the t-test of formaldehyde were a strong positive linear relationship between the active type and the passive type.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.458-458
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• 2013

We investigated a study on the thermal degradation of boron doped zinc-oxide (BZO) layer which used as a transparent conducting layer on the Cu (In1-xGax) Se2 (CIGS) based thin film solar cells. Devices were annealed under the temperature of $100^{\circ}C$ or 100 hours and then Hall measurement was carried out to characterize the parameters of mobility (${\mu}Hall$), resistivity (${\rho}$), conductivity (${\sigma}$) and sheet resistance (Rsh). The initial values of ${\mu}Hall$, ${\rho}$, ${\sigma}$ and Rsh were $29.3cm^2$/$V{\cdot}s$, $2.1{\times}10^{-3}{\Omega}{\cdot}cm$, $476.4{\Omega}^{-1}{\cdot}cm^{-1}$ and $19.1{\Omega}$/${\Box}$ respectively. After the annealing process, the values were $4.5cm^2$/$V{\cdot}s$, $12.8{\times}10^{-3}{\Omega}{\cdot}cm$, $77.9{\Omega}^{-1}{\cdot}cm^{-1}$ and $116.6{\Omega}$/${\Box}$ respectively. We observed that ${\mu}Hall$ and ${\sigma}$ were decreased, and ${\rho}$ and Rsh were increased. In this study, BZO layer plays an important role of conducting path for electrons generated by incident light onthe CIGS absorption layer. Therefore, the degradation of BZO layer characterized by the parameters of ${\mu}Hall$, ${\rho}$, ${\sigma}$ and Rsh, affect to the cell efficiency.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.262-270
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• 2004

Basic experiments were carried out using the THT-IV low-power Hall thruster to examine the influences of magnetic field shape and strength, and acceleration channel length on thruster performance and to establish guidelines for design of high-performance Hall thrusters. Thrusts were measured with varying magnetic field and channel structure. Exhaust plasma diagnostic measurement was also made to evaluate plume divergent angles and voltage utilization efficiencies. Ion current spatial profiles were measured with a Faraday cup, and ion energy distribution functions were estimated from data with a retarding potential analyzer. The thruster was stably operated with a highest performance under an optimum acceleration channel length of 20 mm and an optimum magnetic field with a maximum strength of about 150 Gauss near the channel exit and with some shape considering ion acceleration directions. Accordingly, an optimum magnetic field and channel structure is considered to exist under an operational condition, related to inner physical phenomena of plasma production, ion acceleration and exhaust plasma feature. A new Hall thruster was designed with basic research data of the THT-IV thruster. With the thruster with many considerations, long stable operations were achieved. In all experiments at 200-400 V with 1.5-3 mg/s, the thrust and the specific impulse ranged from 15 to 70 mN and from 1100 to 2300 see, respectively, in a low electric power range of 300~1300 W. The thrust efficiency reached 55 %. Hence, a large map of the thruster performance was successfully made. The thermal characteristics were also examined with data of both measured and calculated temperatures in the thruster body. Thermally safe conditions were achieved with all input powers.

• Journal of People, Plants, and Environment
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• v.22 no.1
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• pp.15-29
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• 2019

The purpose of this study is to investigate the effects of the exhibition displays and events of the Agro-healing Experience Hall in the Agricultural Technology Exhibition 2018 on satisfaction and revisit intention of visitors. A survey was conducted on visitors of the Agro-healing Experience Hall and the responses of 274 visitors excluding 26 cases with inappropriate responses were analyzed. For psychological measurement, the Perceived Restorativeness Scale (PRS), Profile of Mood States (POMS), level of plant gardening experience, satisfaction and loyalty were measured. There was a significant difference among age groups in all four factors of the PRS (repose, fascination, coherence, and legibility). In the case of education level, there was a significant difference in the three factors (repose, fascination, and legibility). In addition, average monthly income showed a significant difference among groups in the two factors (fascination and coherence). As a result of analyzing the mood states of visitors for the exhibition events of the Agro-healing Experience Hall, there was a significant difference among age groups only in the case of vigor (p < .05). As a result of analyzing the correlation between the level of plant gardening activities (3 factors) and PRS (4 factors) in the exhibition events of the Agro-healing Experience Hall, plant preference tendency and plant-related event showed a high positive correlation of 0.5 or more with repose of the PRS factors. A multiple regression analysis was conducted to investigate the effects of the level of plant gardening activities, PRS and POMS on the satisfaction and loyalty of visitors. As a result, it was found that in terms of relative explanatory power over independent variables affecting satisfaction and revisit intention, fascination had the greatest effect, followed by vigor, fatigue, and occupation (company employee). The results of this study suggest that exhibition events of the Agro-healing Experience Hall affect repose, fascination or vigor of visitors, and thus can be used positively to increase satisfaction and revisit intention of visitors.

• Journal of the Microelectronics and Packaging Society
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• v.14 no.3
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• pp.1-6
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• 2007

In this study, the pentacene thin films were prepared by the soluble process, and characterized fur the application of the organic thin film transistor(OTFT) device. To dissolve the pentacene material, two kinds of solvents such as toluene and chloroform were used, and the effects of these solvents on the properties of pentacene thin films coated on ITO/Glass substrate were investigated. Pentacene thin films were prepared by using spin-coating methode and characterized the surface morphology, crystalline and electrical properties. From the AFM measurement, the surface morphology of the pentacene film dissolved with chloroform was improved compared with the one dissolved with toluene solvent. XRD measurement showed that all prepared pentacene film samples were amorphous crystal phases without crystallization of the films. The electrical properties of the pentacene film dissolved with chloroform showed better results than the ones using toluene solvent by hall measurement system. The carrier concentration and the mobility values of pentacene films using chloroform solvent were found to be $-3.225{\times}10^{14}\;cm^{-3}$ and $3.5{\times}10^{-1}\;cm^2{\cdot}V^{-1}{\cdot}S^[-1}$, respectively. The resistivity was about $2.5{\times}10^2\;{\Omega}{\cdot}cm$.

• Proceedings of the Korean Magnestics Society Conference
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• 2009.12a
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• pp.107-108
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• 2009

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.248.2-248.2
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• 2008

• Journal of Sensor Science and Technology
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• v.6 no.4
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• pp.265-273
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• 1997

The TMA gas sensors are fabricated with the ZnO-based thin films grown by a RF magnetron sputtering method. We investigate the surface carrier concentration, Hall electron mobility, electrical resistivity and sensitivity according to temperature variation and TMA gas concentration. The ZnO-based thin film sensors prepared by sputtering in oxygen showed higher surface carrier concentration, higher Hall mobility, higher sensitivity, and lower electrical resistivity than sensors prepared by sputtering in argon. The doping ZnO-based thin film sensors showed the same electrical properties in comparison with nondoping sensors. In case of sputtering on the oxygen gaseous atmosphere, the ZnO-based thin film sensors doped with 4.0 wt.% $Al_{2}O_{3}$, 1.0 wt.% $TiO_{2}$, and 0.2 wt.% $V_{2}O_{3}$ showed the highest surface carrier concentration of $5.95{\times}10^{20}cm^{-3}$, Hall electron mobility of $177\;cm^{2}/V{\cdot}s$, lowest electrical resistivity of $0.59{\times}10^{-4}{\Omega}{\cdot}cm$ and highest sensitivity of 12.1(working temperature, $300^{\circ}C$, TMA gas, 8 ppm).