• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.5
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• pp.506-513
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• 2015

In this paper, we proposed a novel ethanol concentration sensor using microfluidic metamaterial absorber. The metamaterial absorber comprises a split-ring-cross resonator(SRCR) and a microfluidic channel. The SRCR can generate LC resonance that is very sensitive to changes in the effective dielectric constant around the capacitive gap. In addition, microfluidic channels can change the effective dielectric constant of the dielectric substrate by using an infinitesimal quantity of a liquid on the order of microliters. The proposed absorber can detect the electrical properties of different concentration of ethanol. The performance of the proposed absorber is demonstrated using the absorption measurements of a fabricated prototype sample with waveguides. In addition, the simulated results and measurement results show good agreement.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.906-909
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• 2006

The secondary electron emission coefficient $({\gamma})$ of the cathode is an important factor for improving the discharge characteristics of AC-PDPs because of its close relationship to discharge voltage. In AC-PDPs, MgO is most widely used as a surface protective layer. In this experimental, we have investigated the electronic structure of the energy band structure of the MgO layer responsible for the high ${\gamma}$. The MgO layers have been deposited by electron beam evaporation method, where the $O_2$ partial pressures have been varied as 0, $5.2{\times}10^{-5}$ torr, $1.0{\times}10^{-4}$ torr, and $4.1{\times}10^{-4}$ torr, in this experiment. It is noted that work function that is energy gap between surface and first defect level of MgO layer has the lowest value for the highest O2 partial pressure of $4.1^{\ast}10^{-4}$ Torr.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.257-265
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• 2002

A stoichiometric mixture of evaporating materials for AgInS$_2$ single crystal thin films was prepared from horizontal furnace. To obtain the single crystal thin films, AgInS$_2$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the Hot Wall Epitaxy(HWE) system. The source and substrate temperatures were 680 $^{\circ}C$ and 410 $^{\circ}C$, respectively. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction(DCXD). The carrier density and mobility of AgInS$_2$ single crystal thin films measured from Hall effect by van der Pauw method are 9.35${\times}$10$\^$16/ cm$\^$-3/ and 294 $\textrm{cm}^2$/V$.$s at 293 K, respectively. From the optical absorption measurement, the temperature dependence of the energy band gap on AgInS$_2$ single crystal thin films was found to be E$\_$g/(T) : 2.1365 eV - (9.89 ${\times}$ 10$\^$-3/ eV) T$^2$/(2930 + T). After the as-grown AgInS$_2$ single crystal thin films was annealed in Ag-, S-, and In-atmospheres, the origin of point defects of AgInS$_2$ single crystal thin films has been investigated by using the photoluminescence(PL) at 10 K. The native defects of V$\_$AG/, V$\_$S/, Ag$\_$int/, and S$\_$int/ obtained from PL measurements were classified as a donors or acceptors type. And we concluded that the heat-treatment in the S-atmosphere converted AgInS$_2$ single crystal thin films to an optical p-type. Also, we confirmed that In in AgInS$_2$/GaAs did not form the native defects because In in AgInS$_2$ single crystal thin films did exist in the form of stable bonds.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.424-424
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• 2008

Dye-sensitized Solar Cell (DSC) is a new type of solar cell by using photocatalytic properties of $TiO_2$. The electric potential distribution in DSCs has played a major role in the operation of such cells. Models based on a built-in electric field which sets the upper limit for the open circuit voltage(Voc) and/or the possibility of a Schottky barrier at the interface between the mesoporous wide band gap semiconductor and the transparent conducting substrate have been presented. $TiO_2$ thin films were deposited on the FTO substrate by Nd:YAG Pulsed Laser Deposition(PLD) at room temperature and post-deposition annealing at $500^{\circ}C$ in flowing $O_2$ atmosphere for 1 hour. The structural properties of $TiO_2$ thin films have investigated by X-ray diffraction(XRD) and atomic force microscope(AFM). Thickness of $TiO_2$ thin films were controlled deference deposition time and measurement by scanning electron microscope(SEM). Then we manufactured a DSC unit cells and I-V and efficiency were tested using solar simulator.

• Information Systems Review
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• v.7 no.1
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• pp.81-96
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• 2005

Because the web sites are in common today, the access to the web for disabled people and old aging people, what we call accessibility, becomes more important. Even though efforts to reduce the informational gap resulted from the lack of the accessibility have been carried out, the studies in this field in Korea are not still in popular. In this study, previous research on the measurements for the accessibility is reviewed and then a new model measuring accessibility is suggested. To increase the validity of the measurement, both an automated tool and a manual test are employed. First we used the 'A-Prompt', one of the popular automated validation tools and analyzed web sources, and applied manual tests by HPR Screen Reader. With the error rates calculated, the accessibility of the government web sites between Korea and the United States was compared and finally the conclusions were drawn.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.10
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• pp.645-651
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• 2016

Effects of pressure-side winglet width on the tip leakage flow and aerodynamic loss downstream of a turbine blade with a pressure-side squealer rim have been investigated for the tip gap-to-span ratio of h/s = 1.36%. The pressure-side squealer has a fixed height-to-span ratio of $h_p/s=3.75%$ and the pressure-side winglet, which is installed at an elevation of tip surface, has width-to-pitch ratios of w/p = 2.64%, 5.28%, 7.92% and 10.55%. The results show that with increasing w/p, aerodynamic loss in the passage vortex region decreases, whereas that in the leakage flow region increases. As a result, the mass-averaged loss coefficient all over the measurement plane tends to decrease minutely with the increment of w/p. It is concluded that the pressure-side winglet for the pressure-side squealer tip can hardly contribute to the tip-leakge loss reduction.

• Journal of The Korean Society of Integrative Medicine
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• v.2 no.2
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• pp.59-65
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• 2014

Purpose : This study was to investigate the influence of imagery balance for healthy normal people in their twenties. Method : The study has taken a place in Kyung-buk college in Yung-jusi in Kyungbuk with a group of 21 healthy peoples. The study used measurement of good balance. we measured balance for data of each static and dynamic. Training period, a total of 2 weeks. Except Saturday and Sunday, the study did weekdays. Fist, 2-minute relaxation. Second, 6-minute imagine training. Third, 2-minute relaxation. Total 10-minute training was conducted per training. Result : In study, the subjects were compared date for before the study to date for after the study. The subjects showed a little change in each Balance. But, the improvement of balance was not a big change. Conclusion : Image training kinesthetic image using hearing improved incompletely inspite of being no gap, numerically balance.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.2
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• pp.175-180
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• 2015

In this paper, GPS / GLONASS receiving a small active antenna is proposed. A microstrip patch antenna which supports dual-band (GPS and GLONASS) was optimized. The antenna size is $13{\times}13{\times}3.6mm$. The jig was changed to confirm the proposed antenna characteristic size, was adjusted to feed gap of the patch antenna, it was confirmed by change in LNA shield case or not. The antenna jig size is $65.6{\times}13{\times}0.8mm$. The maximum gain of the GPS band is 3.78dBi, the maximum gain of the GLONASS bands is 4dBi. To amplify the Satellite reception signal level, one-stage low noise amplifier(LNA) was designed. The LNA chip was using the BGA715 N7, the LNA gain is 19.9dB. The utilization possibility of the GPS / GLONASS receiving a small active antenna could be confirmed according to compare and analyze the simulation and measurement data.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.5
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• pp.38-44
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• 2007

This paper presented a location and attitude estimation scheme of a capsule endoscope based on ultrasonic ranging. The scheme comprised eight on-capsule ultrasonic sensors to alleviate measurement errors due to irregularities in human body ultrasonic characteristics. It calculated the coordinate values and angles in a Cartesian coordinate system. The Matlab simulation reflecting random errors yielded the average deviations of 0.8mm in the location and $0.2^{\circ}$ in the attitude angle. These values are far smaller than normal intestine movement ranges inside human body, and will contribute accurate diagnosis of intestine.

• Korea journal of population studies
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• v.12 no.2
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• pp.45-55
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• 1989

In recent years the life expectancy of the Korean people has been increasing appreciably because of the improvement in living conditions and public health facilities as well. However, there exist considerable constraints in the measurement of Korea's mortality rate. In elaboration, there are quite a few persons who do not submit birth and death reports, thereby lowering the reliability of statistical data. The 1978-1979 life table of the Korean people is still considered the latest one. Nevertheless, a decade has passed since its publication, and the need for a better life table reflecting realities is inc-reasingly growing. Capitalizing on the annual report of demographic statistics and demographic sample survey data m 1988, I have worked out the 1986 tentative life table of the Korean people and found out the following : 1. The male life expectancy in the 1978-1979 life table of the Korean people is 62.7 years old, and that of the female sex is 69.1 years old whereas the average life expectancy of the male sex in the 1986 life table stands at 66.3 years old, and that of the female sex is 74.5 years old. The average life expectancy is up by 3.5 years old for the male sex and also, up 5.4 years old for the female sex, res-pe ctively. 2. A gap between the male and female life expectancies in the 1978-1979 life table was 6.4 years old, while that of the 1986 life table was 8.2 years old. It means the female life expectancy has increased substantially. 3. The infant mortality rate has decreased, compared with the 1978-1979 level, yet it is still above those of Japan and Taiwan. 4. The mortality rate of the middle - aged men in the forties remains high, as was the case in the 1978-1979 period.