• 한국세라믹학회지
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• 제33권11호
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• pp.1195-1202
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• 1996

To prepare the dielectric thin films of (Pb1-xSrx)TiO3 (x=0.1, 0.2, 0.3, 0.35, 0.5) by the sol-gel process titanium (IV) isopropoxide (Ti[OCH(CH3)2]4) and Pb Sr, acetate were used therefore the thin films were fabricated by dip-coating method. Stability of the sol decreased with addition of Sr content thin films could be fabricated up to 35mol% Over this range precipitation of sol occured thin films couldn't be obtained. Transmittance of thin films at visible range decreased with the increase of heat-treatment temperature but exhibited transmit-tance above 60% in all case. Moreover transmittance of thin films at visible range slightly increased with of addition of Sr,. When thin film containing 30 mol% srontium was heated at 600℃ the best perovskite phase was obtained. The dielectric constant (ε) was 280 and dielectric loss factor (tan δ) was 0.021 and curie tempera-ture (Tc) decreased with the increase of addition of Sr.

• 한국세라믹학회지
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• 제20권2호
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• pp.166-172
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• 1983

In this study the sillicon-alloyed isotropic pyrolytic carbon was deposited in the tumbling bed from the pyrolysis of propane and silicon tetrachloride and investigated whether the silicon-alloyed isotropic pyrolytic carbon deposited in this study was usable as bionaterial or not. The silicon-allyed isotropic pyrolytic carbon was varied by controlling the process variables such as propane con-concentration and the argon flow rate flowing in to the silicon tetrachloride bubbler at a fixed reaction bed tempera-ture of 120$0^{\circ}C$ a rotation of reaction tube of 40 rpm a bed particle weight of 7.5 g and a total flow rate of 21/min; the propane concentration was varied from 10 to 70 and the argon flow rate flowing into the silicon tetrachloride bubble from 0 to 1000 cc/min. The results show that the silicon-alloyed isotropic pyrolytic carbon was obtained at all conditions investigated, . And then the alloyed silicon content is rangion from 7 to 14.5 wt%. The density and deposition rate of deposited silicon-alloyed isotropic carbon increased axxording to silicon content and propane concentration. And the apparent crystal-size(Lc) of pyrolytic carbon is not changed with silicon content. The density and apparant crystallite size are respec-tively in the range of 1.94 to 2.06 and 20 to 25$\AA$ It is shown that the silicon-alloyed isotropic pyrolytic carbon ob-tained in this experiment is usable as biomaterial.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2017년도 춘계학술대회 논문집
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• pp.154-154
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• 2017

Ti-6Al-4V alloys are widely used as metal-lic biomaterials in dentistry and orthopedics due to its excellent biocompatibility and me-chanical properties. However, because of low biological activity, it is difficult to form bone growth directly on the surface of titanium implants. For this reason, surface treatment of plasma electrolytic oxidation(PEO) was used for dental implants. To enhance bioac-tivity on the surface, strontium(Sr) and sili-con(Si) ions can be added to PEO treated sur-face in the electrolyte containing these ions. The presence of Sr in the coating enhances osteoblast activity and differentiation, where-as it inhibits osteoclast production and prolif-eration. And Si has been found to be essen-tial for normal bone, cartilage growth, and development. In this study, electrochemical characteristics of Ca, P, Sr, and Si ions from PEO-treated Ti-6Al-4V alloy surface was re-searched using various experimental instruments. DC power is used and Ti-6Al-4V al-loy was subjected to a voltage of 280 V for 3 minutes in the electrolyte containing 5, 10, 20M% Sr ion and 5M% Si ion. The morphol-ogies of PEO-treated Ti-6Al-4V alloy by electrochemical anodization were examined by field-emission scanning electron micro-scopes (FE-SEM), energy dispersive x-ray spectroscopy (EDS), x-ray diffraction (XRD) and corrosion analysis using AC impedance and potentiodynamic polarization test in 0.9% NaCl solution at similar body tempera-ture using a potentiostat with a scan rate of 1.67mV/s and potential range from -1500mV to + 2000mV.

• 한국재료학회지
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• 제10권10호
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• pp.698-702
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• 2000

$Al_{0.24}Ga_{0.76}As/GaAs$ 다중 양자우물 구조의 고아 흡수 특성을 표면 광전압 방법을 사용하여 연구하였다. SPV 측정결과 1.42eV 부근에서 두 개의 신호가 나탔으며, 이는 화학적 에칭으로 GaAs 기판의 신호와 GaAs 완충층과 관련된 신호임을 확인 할 수 있었다. $Al_{0.24}Ga_{0.76}As$와 관련된 전이 에너지를 관찰하고, Kuech 등이 제안한 조성식을 이용하여 Al 조성(x=24%)을 결정하였다. 그리고 다중 양자우물에서 나타나는 전이 에너지 값들은 envelope-weve function approximation(EFA)로 계산한 이론치와 잘 일치하였다. 입사광의 세기에 따라 광 전압이 선형적으로 변한다는 것을 알 수 있었고, 온도가 감소함에 따른 전이 에너지의 변화를 관찰하였다.

• 한국작물학회지
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• 제32권4호
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• pp.409-416
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• 1987

본시험은 남부지역에 있어서 파종기 이동이 콩의 건물생산능력 및 생리, 생태적특성에 미치는 영향을 파악하여 적정 파종 한계기를 제시하고자 ＇82년∼＇84년도 3개년에 걸쳐 시험을 실시하였던바 다음과 같은 결과를 얻었다. 1. 만파할수록 개화일수, 성숙기 개화기간 등은 크게 단축되었고 품종가 차이도 인정되었으며 엽후는 만파에 의하여 두꺼워지는 반면, 엽면적은 감소하였고, CGR은 활엽기를 전후하여 뚜렷한 차이를 보였는데 7월 9일 파종기는 타 파종기의 50% 내외의 작물생자율을 나타내었다. 2 건물중은 만파할수록 현저히 감소되었으나 100 입중을 제외한 다른 수량구성요소는 5월 10일과 5월 30일간에 비슷한 경향을 나타냈다. 3. 10a당 수량은 5월 10일 파종구 225kg, 5월 30일 239kg, 6월 19일 188kg, 7월 9일은 101kg으로 5월 30일 파종구의 수량이 가장 높았으며 품종간에는 단엽콩이 파종기 이동에 의한 수량변이폭이 가장 작았다.