• Journal of the Korean Chemical Society
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• v.25 no.1
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• pp.21-25
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• 1981

A study was made of the influence of butyl alcohol on the distribution coefficients of barium and mercury ions between the ion exchange resin, Dowex 50w-x8, 200~400 mesh and solutions containing hydrochloric acid, butyl alcohol and water. The determination of the distribution coefficients of barium and mercury are made by using the batch method. The distribution coefficients of metal ions decrease generally as the number of branches of carbon in the molecule of butyl alcohol increase. It shows that solubility in water and stereo-isomerism of the butyl alcohol have influence upon the distribution coefficient of barium and mercury.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.325-329
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• 1998

In this paper, the (Sr$_{1-x}$ Ca$_{x}$)TiO$_3$(SCT) thin films were deposited at various substrate temperature using RF magnetron sputtering method on optimized Pt-coated electrodes (Pt/TiN/SiO$_2$/Si). An influence of substrate temperature and annealing temperature on the structural and dielectric properties are investigated. The substrate temperature changed from 100[$^{\circ}C$] to 500[$^{\circ}C$] and crystalline SCT thin films were deposited abode 400[$^{\circ}C$]. All thin films had (111) preferred orientation, the (100) oriented films were obtained at the substrate temperature above 400[$^{\circ}C$]. The dielectric constant changes almost linearly in the temperature region of -80~+90[$^{\circ}C$], the temperature characteristics of the dielectric loss exhibited a stable value within 0.1, then not affected by substitutional contents. The capacitance characteristics appears a stable value within $\pm$5[%].

• Proceedings of the KSR Conference
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• 2009.05b
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• pp.295-308
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• 2009

Now, the goal of the third generation KTX project is to create a new species of high speed train in order to open a new era of high speed railway system in history by authentic Korean technology and innovative design. Now the third generation KTX, must go beyond the original stagnant paradigm and be positioned as an emotional resource which is creating a shift in the public's perspective of transportation and expanding the idea that transportation intersects the two distinct realms of culture and environment as well. In addition, the overall design should reflect the Korean culture and characteristics, simple yet resonant, both the interior space and the exterior fuselage should portray the dynamic heritage of Korea such as the powerful yet subdued energy of Jung Joong Dong. In short, through the symbolic in Korean, Dong(Dynamics), Mek(Pulse), Ryu(Flow), Gam(Sensibility), the third generation KTX design project aims to create an new identity of Korean high speed railway which can stand globally.

• Proceedings of the Korea Multimedia Society Conference
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• 2004.05a
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• pp.409-412
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• 2004

무선통신은 현재 우리 삶의 일부분을 차지하고 있으며, 유선 통신의 한계인 공간적 제약성을 극복함으로서 일상 또는 산업현장에서 없어서는 안되는 아주 중요한 부분이 되어 있다. 현재 산업현장에서 사용되고 있는 유선과 무선콘트롤러의 성능을 향상시키기 위해 컨볼루션 부호와 CRC부호를 적용한 무선 콘트롤러를 구현하였다. 400Mhz대역의 RF모듈을 사용하여 송수신 프로그램에 컨볼루션 부호를 적용하였을때와 적용하지 않았을때의 각각의 수신율을 테tm트 비교해 보았다. 컨볼루션 부호는 POLYNOMIAL함수를 g1(X) =1 + X + X$^2$, g2(X) =1 + X$^2$로 사용하였고 구속장 K=3, 부호율 1/2인 부호를 사용하였다. CRC부호는 POLYNOMIAI. 함수를 X$^{15}$ + X$^2$+ 1 로 사용하여 총 CRC비트는 16bit가 되게 하였다.

• Bulletin of the Korean Chemical Society
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• v.18 no.12
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• pp.1249-1256
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• 1997

Single phase La1-xSrxCoO3 (x≤0.2) was synthesized as a uniform sized 100 nm particulates with relatively high surface area of 20-30 m2/g, at low temperature (≥600 ℃), from a polymeric gel precursors prepared by using poly(vinyl alcohol) as homogenizer. No minor phase developed during the crystallization when polymer/metal mole ratio was higher than 3. As the polymer/metal mole ratio was raised in the gel, the amount of carbonaceous residues in the amorphous solid precursor prepared by heating the gel at 300 ℃ increased. Most of the residues were eliminated by exothermic thermal decomposition around 400 ℃. The amount of residual carbon (less than 1%) left in the crystalline La1-xSrxCoO3 decreased as more polymer was used, eliminating detrimental effect which might be posed by using large amount of organic homogenizer. The crystal structure of La1-xSrxCoO3 synthesized at temperature lower than 800 ℃ was observed to be shifted from rhombohedral to more symmetric cubic. The structure shifted back to rhombohedral as the cubic sample was annealed at 1000 ℃.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.10 no.6
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• pp.418-424
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• 2000

Pure $TiO_2$and 10 mol % Pb-doped $TiO_2(Pb_xTi_{1-x}O_2$(x = 0.1)) powder and thin films have been prepared by the sol-gel method. Titanium isopropoxide and ethanol are used for pure $TiO_2$, lead acetate trihydrate and titanium triisopropoxide monoacethylacetonate are used for Pb-doped $TiO_2$, respectively. Films are coated on p-type Si(100) wafer and ITO glass substrates by the sol-gel spin-coating method. The powder and multi-coated films are annealed at different temperature (400~$800^{\circ}C$) for phase formation and crystallization. TGA/DTA, XRD analysis, SEM and UV-visible transmission spectroscopy have been used to study the characteristics of the powder and films. XRD results show that the films are polycrystalline, anatase type and oriented predominantly to the A(101) plane. A slight shift in the d-spacing for the Pb-doped film indicates the incorporation of the Pb into $TiO_2$lattice. A shift of the absorption wavelength in the transmission spectrum towards longer wavelength has been observed about $Pb_xT_{1-x}O_2$(x = 0.1) thin film, which indicates a decrease in the bandgap of $TiO_2$upon Pb-doping.

• Journal of the Korean Society of Radiology
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• v.9 no.1
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• pp.17-21
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• 2015

Recently, As people's interest in the health of teeth is increased in the medical field changed into aging society, the number of times for the radiological diagnosis is increased. It can be said that the radiation exposure dose of Korean population is increased. It is also growing concern about radiation exposure. Therefore, the basic data for the dental panoramic X-ray system, its investigation and measuring the radiation dose is needed. In this study, we used ALOKA PDM-117 dosimeter and estimated a two-dimensional dose distribution of the dental panoramic X-ray system (VATEC Pax-400). Dose evaluation about the distribution is confirmed from the point of radiation exposure of a patient. Dose distribution of the dental panoramic X-ray system irradiated chin and the facial region to high dose as well as the parts of teeth. It was founded that the eye lens which are sensitive to radiation are exposed to unnecessary radiation, considering the effect of scattered radiation. The results of this study will be used more accurate dose assessment in a variety of object size and location of measuring dose.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.4
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• pp.141-143
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• 2008

Purpose: This study investigated visual acuity and refractive error in elementary schoolchildren and examined relationship between visual acuity and refractive error. Methods: Naked visual acuity and refractive error for selected 200 schoolchildren (400 eyes) of 1st, 3rd and 6th grades. Results: The refractive error in hyperopia was gradually decreased and visual acuity was increased as higher grade. The regression line of Y=2.1471X-3.1484 (F=313.9377, P<0.001) and closed inter-relationship were found between visual acuity and refractive error in myopia. The regression line equation of Y=-0.6854X+1.1764 (F=7.054, P<0.01) and closed inter-relationship were found between visual acuity and refractive error in hyperopia. The relationship between visual acuity and refractive error in astigmatism was Y=2.2509X-2.8738 (F=21.7952, P<0.001) and closed inter-relationship was found. Conclusions: Myopia, hyperopia and astigmatism showed closed inter-relationship with visual acuity.

• The Plant Pathology Journal
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• v.31 no.4
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• pp.343-349
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• 2015

Citrus canker caused by Xanthomonas citri subsp. citri (Xcc) is one of the most important bacterial diseases of citrus. Because citrus canker is not found in many countries including European Union and Australia, Xcc is strictly regulated in order to prevent its spread. In this study, the effects of X-irradiation on Xcc growth either in the suspension or on the surface of citrus fruits were investigated. The suspension containing $1{\times}10^7cfu/ml$ of Xcc was irradiated with different absorbed doses of X-irradiation ranging from 50 to 400 Gy. The results showed that Xcc was fully dead at 400 Gy of X-irradiation. To determine the effect of X-irradiation on quarantine, the Xcc-inoculated citrus fruits were irradiated with different X-ray doses at which Xcc was completely inhibited by an irradiation dose of 250 Gy. The $D_{10}$ value for Xcc on citrus fruits was found to be 97 Gy, indicating the possibility of direct application on citrus quarantine without any side sterilizer. Beside, presence of Xcc on the surface of asymptomatic citrus fruits obtained from citrus canker-infected orchards was noted. It indicated that the exporting citrus fruits need any treatment so that Xcc on the citrus fruits should be completely eliminated. Based on these results, ionizing radiation can be considered as an alternative method of eradicating Xcc for export of citrus fruits.

• Journal of Biomedical Engineering Research
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• v.26 no.1
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• pp.43-47
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• 2005

We have developed a small bore x-ray CT for small animal imaging with a linear x-ray detector array and small-scale slip rings. The linear x-ray detector array consists of 1024 elements of 400□m×400□m with a gadolinium oxysulfide (GOS) scintillator on top of them. To avoid use of expensive large diameter slip rings for projection data transmission from the X­ray detector to the image reconstruction system, we used the wireless LAN technology. The projection data are temporally stored in the data acquisition system residing on the rotating gantry during the scan and they are transmitted to the image reconstruction system after the scan. With the wireless LAN technology, we only needed to use small-scale slip rings to deliver the AC electric power to the X-ray generator and the power supply on the rotating gantry. The performances of the small animal CT system, such as SNR, contrast, and spatial resolution, have been evaluated through experiments using various phantoms. It has been experimentally found that the SNR is almost linearly proportional to the tube current and tube voltage, and the minimum resolvable contrast is less than 30 CT numbers at 40kVp/3.0㎃. The spatial resolution of the small animal CT system has been found to be about 0.9Ip/㎜. Postmortem images of a piglet is also presented.