• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.231-231
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• 2011

본 연구에서는 co-sputtering 시스템을 이용하여 아나타세 TiO2의 도핑 농도 변화에 따른 다성분계 TiO2-ITO (TITO) 박막의 전기적, 광학적, 구조적 특성 변화 및 급속 열처리(RTA) 공정에 따른 전기적, 광학적 특성 변화를 분석하였다. 실험을 위해 아나타세 TiO2 타겟과 ITO 타겟(10 wt% $SnO_2$ doped $In_2O_3$)이 tilted cathode에 장착되었으며, ITO 타겟의 인가전류를 120 W로 고정한 채 아나타세 TiO2 타겟의 인가전류를 증가시킴으로써 도핑 농도를 변화하였다. 제작된 TITO 투명 전극의 전기적, 광학적, 구조적 특성 평가를 위해 four-point probe measurement, Hall effect measurement, UV/Vis. spectrometry, scanning electron microscopy (SEM) 이용하여 각각의 특성을 분석하였다. 상온에서 제작된 TITO의 경우 최적화된 $TiO_2$ 인가전류 100W에서 460.8 ohm/sq. 의 전기적 특성과 가시광선 영역 400~550 nm에서 85% 이상의 광학적 투과율을 확보할 수 있었다. 뿐만 아니라 상온에서 최적화된 TITO 투명 전극의 급속 열처리 시 600$^{\circ}C$ 급속 열처리 조건에서 매우 낮은 25.94 ohm/sq.면저항, $5.1{\times}10^{-4}$ ohm-cm 비저항과 81% 투과율을 확보할 수 있었다. 아나타세 $TiO_2$가 도핑된 TITO 투명 전극의 급속 열처리 공정에도 불구하고 매우 평탄한 표면을 나타냄을 SEM 이미지를 통하여 확인할 수 있었다. 이러한 TITO 투명 전극의 우수한 전기적, 광학적, 구조적 특성은 indium saving 투명 전극으로써 고가 ITO 박막의 대치가능성을 나타낸다.

• Korean Journal of Materials Research
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• v.25 no.4
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• pp.177-182
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• 2015

Sb-doped $SnO_2$(ATO) thin films were prepared using electrospinning. To investigate the optimum properties of the electrospun ATO thin films, the deposition numbers of the ATO nanofibers(NFs) were controlled to levels of 1, 2, 4, and 6. Together with the different levels of deposition number, the structural, chemical, morphological, electrical, and optical properties of the nanofibers were investigated. As the deposition number of the ATO NFs increased, the thickness of the ATO thin films increased and the film surfaces were gradually densified, which affected the electrical properties of the ATO thin films. 6 levels of the ATO thin film exhibited superior electrical properties due to the improved carrier concentration and Hall mobility resulting from the increased thickness and surface densification. Also, the thickness of the samples had an effect on the optical properties of the ATO thin films. The ATO thin films with 6 deposited levels displayed the lowest transmittance and highest haze. Therefore, the figure of merit(FOM) considering the electrical and optical properties showed the best value for ATO thin films with 4 deposited levels.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.43 no.1
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• pp.54-58
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• 1998

Four introduced forage rape cultivars 'Akela', 'Ramon', 'Sparta', and 'Velox' and a leading rapeseed cultivar Hall-ayuchae were seeded on 1 October 1994 on 20-cm rows at seeding rates of 3, 5, 7, 10, 13, and IS kg/ha to select the best adapted forage rape cultivars and to determine the optimum seeding rate in the Cheju area. Days to flowering of each cultivar was not significantly affected by seeding rate. Average plant height increased from 151 to 164 cm as seeding rate increased from 3 to 10 kg/ha and then decreased to 156 cm at 15 kg/ha. Stem diameter linearly decreased with increasing seeding rate. The optimum seeding rate for the greatest dry matter and protein yields of five cultivars ranged from 10.7 to 11.8 and 10.8 to 14.4 kg/ha, respectively. Dry matter yields of five cultivars ranged from 7.72 and 22.01 Mg/ha. Sparta produced the greatest dry matter yield, followed by Akela, Ramon, Hallayuchae, and Velox. Crude protein yields of five cultivars ranged from 0.29 to 1.08 Mg/ha. Sparta produced the greatest crude protein yield, followed by Akela, Ramon, Velox, and Hallayuchae. As seeding rate increased, crude protein content linearly increased but crude fiber content linearly decreased. The forage cultivars had higher crude protein and lower crude fiber than the oilseed cultivar Hallayuchae. Our results demonstrate that Sparta was the best adapted cultivar to Cheju area and the optimum seeding rate for Sparta was about 10 kg/ha.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.5115-5122
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• 2013

This paper has studied about the development and application of landslide collapse prediction real-time monitoring system based on USN to detect and measure the collapse of landslide. The rainfall measuring sensor, gap water pressure sensor, indicator displacement measuring sensor, index inclination sensor, water content sensor and image analysis sensor are selected and these are applied on the test bed. Each sensor's operation and performance for reliability verification is tested by the instrument which is installed in the field. As the result, u-IT based real-time landslide monitoring system which is developed by this research for landslide collapse detection could minimize life and property damages because it makes advance evacuation with collapse risk pre-estimate through real-time monitoring on roadside cut and bedrock slopes. This system is based on the results of this study demonstrate the effect escarpment plan are spread throughout.

• Journal of Bio-Environment Control
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• v.15 no.1
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• pp.8-20
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• 2006

This research was conducted to determine the plant growth and nutrient contents of potted chrysanthemum 'Lima Honey' as influenced by application rate of dolomite in three root media, peatmoss+vermiculite (1:1, v/v), peatmoss+composted rice hall (1:1, v/v), and peatmoss+composted pine bark (1:1, v/v). All root media contained polyacrylic acid sodium salt (PASS) at a rate of $4.5g L^{-1}$. In crop growth at 40 and 80 days after transplanting, elevated application rates of dolomite up to $6.0g L^{-1}$ in three root media increased fresh and dry weights per plant. But the treatment of $9.0g L^{-1}$ had less fresh and dry weights than those of $6.0g L^{-1}$. Tissue phosphorus content decreased and those of Ca and Mg increased by the elevated application rates of dolomite. Elevated application rates of dolomite in three root media resulted in the increase of pH, EC, and the concentrations of K, Ca, and Mg at 43 days after transplanting. Those at 80 days after transplanting were also increased, but the differences among treatments were less significant as compared to those at 43 days after transplanting. From the results of dry weight in potted chrysanthemum 'Lima Honey', the proper application rate of dolomite to three root media containing PASS at a rate of $4.5g L^{-1}$ were $6.0g L^{-1}$.

• Journal of Bio-Environment Control
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• v.15 no.1
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• pp.21-34
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• 2006

This research was conducted to determine the plant growth and nutrient contents of potted chrysanthemum 'Lima Honey' as influenced by application rate of fused superphosphate (FSSP) in three root media, peatmoss+vermiculite (1:1, v/v; PV), peatmoss+composted rice hall (1:1, v/v; PR), and peatmoss+composted pine bark (1:1, v/v; PB). All root media contained polyacrylic acid sodium salt at a rate of $4.5g L^{-1}$. The treatment of $1.4g L^{-1}$ in PV and those of $0.7g L^{-1}$ in PR and PB had the greatest fresh and dry weights in each root medium at both 43 and 80 days after transplanting. Elevated application rates of FSPP increased tissue contents of N, P, and K at both 43 and 80 days after transplanting in PV medium. However, the differences in tissue contents of N, P and K in PR medium were less significant among treatments of FSPP. The pre-planting FSPP also less affected the tissue contents of nutrients at 80 days after transplanting as compared to those at 43 days after transplanting. Elevated application rates of FSPP in PV medium increased EC and the concentrations of $NO_3,\;P_2O_5$, K, Ca, and Mg in soil solution of root media at 43 days after transplanting. The EC in PV medium at 80 days after transplanting was higher than that at 43 days after transplanting. The EC in all root media at 80 days after transplanting was not different among treatments of FSPP.

• Journal of Sensor Science and Technology
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• v.15 no.6
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• pp.397-405
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• 2006

Single crystal $AgGaSe_{2}$ layers were grown on thoroughly etched semi-insulating GaAs(100) substrate at $420^{\circ}C$ with hot wall epitaxy (HWE) system by evaporating $AgGaSe_{2}$ source at $630^{\circ}C$. 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 single crystal $AgGaSe_{2}$ thin films measured with Hall effect by van der Pauw method are $4.05{\times}10^{16}/cm^{3}$, $139cm^{2}/V{\cdot}s$ at 293 K, respectively. The temperature dependence of the energy band gap of the $AgGaSe_{2}$ obtained from the absorption spectra was well described by the Varshni's relation, $E_{g}(T)$=1.9501 eV-($8.79{\times}10^{-4}{\;}eV/K)T^{2}$/(T+250 K). The crystal field and the spin-orbit splitting energies for the valence band of the $AgGaSe_{2}$ have been estimated to be 0.3132 eV and 0.3725 eV at 10 K, respectively, by means of the photocurrent spectra and the Hopfield quasicubic model. These results indicate that the splitting of the ${\Delta}So$ definitely exists in the ${\Gamma}_{5}$ states of the valence band of the $AgGaSe_{2}$. The three photocurrent peaks observed at 10 K are ascribed to the $A_{1}-$, $B_{1}-$, and $C_{1}-$exciton peaks for n=1.

• Journal of Sensor Science and Technology
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• v.14 no.3
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• pp.160-168
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• 2005

ZnO epilayer were synthesized by the pulesd laser deposition(PLD) process on $Al_{2}O_{3}$ substrate after irradiating the surface of the ZnO sintered pellet by the ArF(193 nm) excimer laser. The epilayers of ZnO were achieved on sapphire ($Al_{2}O_{3}$) substrate at a temperature of $400^{\circ}C$. The crystalline structure of epilayer was investigated by the photoluminescence. The carrier density and mobility of ZnO epilayer measured with Hall effect by van der Pauw method are $8.27{\times}1016cm^{-3}$ and $299cm^{2}/V{\cdot}s$ at 293 K, respectively. The temperature dependence of the energy band gap of the ZnO obtained from the absorption spectra was well described by the Varshni's relation, $E_{g}(T)$=3.3973 eV-($2.69{\times}10^{-4}$ eV/K)$T^{2}$/(T+463K). The crystal field and the spin-orbit splitting energies for the valence band of the ZnO have been estimated to be 0.0041 eV and 0.0399 eV at 10 K, respectively, by means of the photocurrent spectra and the Hopfield quasicubic model. These results indicate that the splitting of the ${\Delta}so$ definitely exists in the ${\Gamma}_{6}$ states of the valence band of the ZnO. The three photocurrent peaks observed at 10 K are ascribed to the $A_{1}-$, $B_{1}-$, and $C_{1}-$exciton peaks for n = 1.

• The Journal of the Korea Contents Association
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• v.15 no.3
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• pp.57-67
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• 2015

The aim of this study was to categorize and analyze the patterns of the observation type in the experiential learning through the science museum for elementary gifted students in science. Ten science-gifted students were included and analyzed in this study and during experiential learning in the science museum, the participants freely expressed their observation of their own languages and all observations and dialogue were recorded. The results are listed below. The cognitive aspect, especially question and response activity without their personal opinion, was the most frequently used item. Among the affective aspects, item for 'recommendation' was often used. In accordance to observation type, most participants overall observed single object independently of time. Also, participants mostly observed objects visually using qualitative method without manipulation. Therefore verbal interaction through question might have a positive effect on frequency and diversity of observation. Project learning, such as particular exhibition hall, exploratory time of concentration by students, or study paper will be capable of creating a effective observation learning in order to induce a variety of observation of science gifted students in the experiential learning through the science museum.

• Transactions on Electrical and Electronic Materials
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• v.10 no.1
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• pp.24-27
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• 2009

N-doped ZnO thin films were deposited on n-type Si(100) and homo-buffer layer, and undoped ZnO thin film was also deposited on homo-buffer layer by RF magnetron sputtering method. After deposition, all films were in-situ annealed at $800^{\circ}C$ for 5 minutes in ambient of $O_2$ with pressure of 10Torr. X -ray diffraction shows that the homo-buffer layer is beneficial to the crystalline of N-doped ZnO thin films and all films have preferable c-axis orientation. Atomic force microscopy shows that undoped ZnO thin film grown on homo-buffer layer has an evident improvement of smoothness compared with N-dope ZnO thin films. Hall-effect measurements show that all ZnO films annealed at $800^{\circ}C$ possess p-type conductivities. The undoped ZnO film has the highest carrier concentration of $1.145{\times}10^{17}cm{-3}$. The photoluminescence spectra show the emissions related to FE, DAP and many defects such as $V_{Zn}$, $Zn_O$, $O_i$ and $O_{Zn}$. The p-type defects ($O_i$, $V_{Zn}$, and $O_{Zn}$) are dominant. The undoped ZnO thin film has a better p-type conductivity compared with N-doped ZnO thin film.