• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.1131-1131
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• 2001

To develop a nondestructive quality evaluation technique of fruits, a K-mean algorism is applied to near infrared (NIR) spectroscopy of apples. The K-mean algorism is one of neural network partition methods and the goal is to partition the set of objects O into K disjoint clusters, where K is assumed to be known a priori. The algorism introduced by Macqueen draws an initial partition of the objects at random. It then computes the cluster centroids, assigns objects to the closest of them and iterates until a local minimum is obtained. The advantage of using neural network is that the spectra at the wavelengths having absorptions against chemical bonds including C-H and O-H types can be selected directly as input data. In conventional multiple regression approaches, the first wavelength is selected manually around the absorbance wavelengths as showing a high correlation coefficient between the NIR $2^{nd}$ derivative spectrum and Brix value with a single regression. After that, the second and following wavelengths are selected statistically as the calibration equation shows a high correlation. Therefore, the second and following wavelengths are selected not in a NIR spectroscopic way but in a statistical way. In this research, the spectra at the six wavelengths including 900, 904, 914, 990, 1000 and 1016nm are selected as input data for K-mean analysis. 904nm is selected because the wavelength shows the highest correlation coefficients and is regarded as the absorbance wavelength. The others are selected because they show relatively high correlation coefficients and are revealed as the absorbance wavelengths against the chemical structures by B. G. Osborne. The experiment was performed with two phases. In first phase, a reflectance was acquired using fiber optics. The reflectance was calculated by comparing near infrared energy reflected from a Teflon sphere as a standard reference, and the $2^{nd}$ derivative spectra were used for K-mean analysis. Samples are intact 67 apples which are called Fuji and cultivated in Aomori prefecture in Japan. In second phase, the Brix values were measured with a commercially available refractometer in order to estimate the result of K-mean approach. The result shows a partition of the spectral data sets of 67 samples into eight clusters, and the apples are classified into samples having high Brix value and low Brix value. Consequently, the K-mean analysis realized the classification of apples on the basis of the Brix values.

• 방사성폐기물학회지
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• 제15권3호
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• pp.219-230
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• 2017

본 연구는 경주 중 저준위처분장 2단계 표층처분시설의 폐쇄 후 안전성에 대한 불확실성을 예측 평가하기 위하여 수행되었다. 다중덮개와 처분고의 건전/열화를 고려한 총4가지의 시나리오를 도출하여 강우침투 시 예상되는 처분시설 내부의 유체 이동을 모사하였다. 강우 조건은 총 30년(1985~2014) 간의 월평균 데이터를 적용하였으며, 시뮬레이션 기간은 제도적 관리기간인 300년으로 설정하였다. 처분덮개와 처분고 콘크리트 모두 건전성을 유지하는 조건의 기본 시나리오 평가 결과, 처분시설 내부의 처분고를 완전히 포화시키지 못하는 것을 확인할 수 있었다. 다중 덮개층을 구성하는 8개 층의 각 매질의 모세관 압력과 투과도 차이로 인하여 다중 덮개층이 효과적으로 차수 배수 역할을 하는 것으로 나타났다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.717-724
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• 2011

In order to commercialize the track systems including the turnouts developed in Korea, the guideline of technical and systematic performance evaluation considering local environment was established on Aug. 2010. It consists of a technical compatibility, laboratory test and in-service test. Technical compatibility and laboratory test of the domestically-developed swing-nose crossing turnout on slab track(F18.5) were evaluated according to the guideline. And then in-service test was performed for the turnout installed at the 2nd phase site of Kyung-Bu HSR. In-service test is comprised of monitoring, and field and on-board test during KTX operation, where monitoring is to check the maintainability, and field and on-board test is to confirm structural and running safety. This paper is intended to explain the requirements for the in-serve test and analyze the results of monitoring and the data measured at field and on-board. Based on the in-service test, it is proven that performance of the domestically-developed swing-nose crossing turnout on slab track(F18.5) well satisfies the requirements of the guideline.

• Bulletin of the Korean Chemical Society
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• 제34권6호
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• pp.1679-1683
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• 2013

Intergrowth perovskite type complex oxides $La_{0.8}Ln_{0.2}Sr_2MnCrO_{7-{\delta}}$ (Ln=La, Nd, Gd, and Dy) have been synthesized by sol-gel method. Rietveld profile analysis shows that the phases crystallize with tetragonal unit cell in the space group I4/mmm. The unit cell parameters a and c decrease with decreasing effective ionic radius of the lanthanide ion. The magnetic studies suggest that the ferromagnetic interactions are dominant due to $Mn^{3+}$-O-$Mn^{4+}$ and $Mn^{3+}$-O-$Cr^{3+}$ double exchange interactions. Both Weiss constant (${\theta}$) and Curie temperature ($T_C$) increase with decreasing ionic radius of lanthanide ion. It was found that the transport mechanism is dominated by Mott's variable range hopping (VRH) model with an increase of Mott localization energy.

• Journal of Periodontal and Implant Science
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• 제25권2호
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• pp.418-437
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• 1995

The effect of the hydroxyapatite coatings on Titanium implants has been the subject of recent investigations. So far, the use of HA coating remains substantially controversial.This study was aimed to evaluate histologically the bone healing patterns around titanium plasm sprayed(TPS) amd HA-coated implant after implantation into the femur neck of ten adult dogs. After implantation, animals were sacrificed at the intervals of 2,4,6,8 and 12 weeks.The fluorescent dyes were injected on the postoperative 4th and 12th week into the animals supposed to be killed at the 12th week. The morphology and direction of new bone formation was similar in both TPS and HA-coated implants.There was a tendency toward more bone formation in the cortical bone area than in the cancellous bone area. Histologically,in the interface of the HA-coated implants, bone response and bone maturation was faster, compared to the TPS implants in the 2nd and 4th week. By fluorescent microscopy, new bone formation was active in the 4th week around both implants and was directed from the periosteum overlying cortical bone to the cancellous bone. These results suggest that the bone formation and maturation is faster during the early healing stage in the interface of the HA-coated implant and where the cortical bone quality is poor, HA coated implant is superior to the TPS implant in the early phase of new bone formation.

• Natural Product Sciences
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• 제12권3호
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• pp.166-173
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• 2006

Silymarin is an antihepatotoxic substance isolated from the fruits of silybum mariamum. Possibly due to their antioxidant and membrane stabilizing properties, the compounds was shown to protect various organs and cells against a number of insults (Kvasnicka et al., 2003). Among the main silymarin components, [silybin($SB_A,\;SB_B$, isosilybin ($ISB_A,\;ISB_B$) silydianin (SD) and silychristin (SC)], silybin is the major pharmacologically active compound. Korean Pharmaceutical Codex (2nd ed.) describes silybin as the main substance of Cardus Marianus extract as supportive treatment of chronic inflammatory liver disorders. The aim of this work was to analyze silybin from various preparations containing cardus marianus extract, nicotinamide, and riboflavin (CNR). Nine commercial products were tested using reversed-phase HPLC-PDA assay. The limits of detection and quantification were $0.2\;{mu}g/ml$ and $1\;{mu}g/ml$, respectively. Calibration curve showed a good linearity ($r^2$=1.00000) in the range of $1{\sim}500\;{\mu}g/ml$ of silybin standard solutions.

• 한국인터넷방송통신학회논문지
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• 제19권2호
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• pp.97-102
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• 2019

위성항법 시스템은 민간 분야뿐만 아니라 군의 다양한 무기체계에서 위치 및 시각 동기화 등의 중요한 정보를 제공하는 역할을 수행하고 있으며 활용분야와 의존도가 높아지고 있다. 이에 따라, 위성항법 장치를 활용하는 무기체계에 대응하기 위해 전자파를 방사하여 위성항법장치를 기만하고자 하는 연구가 활발히 이루어지고 있다. 위성항법 기만신호는 수신기에 전파 교란신호를 방사하여 항법을 하지 못하도록 하거나 허위 위치와 속도로 오인하도록 유도하는 기술을 의미한다. 그 중 스푸핑 기술은 기만하고자 하는 수신기에서 수신하고 있는 코드 위상/도플러 주파수/항법 메시지와 동기되어 위성항법 신호 대신 기만신호를 획득하고 추적할 수 있도록 신호를 송신해주는 것이다. 본 논문에서는 SDR 수신기를 이용하여 GPS L1 C/A 기만신호에 의한 수신기 추적 알고리즘 영향성을 분석하고 기만 신호에 대한 효과도를 분석하였다.

• 한국전기전자재료학회논문지
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• 제36권1호
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• pp.70-73
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• 2023

To improve superconductor properties, the size of the crystal grains of the superconductor should be adjusted, the amount of electricity flowing through the superconductor should be increased, and the superconductor should be designed to withstand external magnetic fields. It is necessary to control the microstructure so that many flux pinning centers are developed inside the superconductor so that defects are generated physically or chemically, and the micro secondary phase for trapped magnetic flux must be dispersed inside the superconductor. In order to measure the superconducting magnetic force of the superconducting bulk in a simplified manner, the superconducting magnetic force was analyzed using an Nd-Fe-B permanent magnet of 3.80 kG. In particular, by delaying the growth of partially melted Y₂BaCuO₅ particles, we devised a plan to refine Y₂BaCuO₅ particles to effectively improve superconducting magnetic force, and analyzed superconducting magnetic force in a single crystal YBa₂Cu₃O_7-y superconducting bulk using a gauss meter. The melted superconducting bulk traps 80% or more of the applied magnetic field, and can be used as a bulk magnet of high magnetic field magnetization applicable to electric power equipment.

• 분석과학
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• 제13권5호
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• pp.573-583
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• 2000

몇 가지 식물섬유, 합성섬유 및 혼합섬유를 원료로 하여 비표면적 차이가 나는 세가지 등급의 활성탄소섬유를 제조하고 입상활성탄을 대조흡착제로 하여 페놀 및 메틸렌블루의 액상흡착특성을 비교 검토하였다. 이들 흡착질 수용액의 활성탄소섬유에 대한 흡착등온선, 흡착속도 및 컬럼통액실험을 통하여 돌파점곡선을 측정하였다. 페놀 및 메틸렌블루의 흡착등온은 모두 type I을 나타내었으며 낮은 평형농도에서도 높은 흡착량을 나타내었다. 흡착질에 대한 활성탄소섬유의 흡착속도는 활성탄에 비하여 100배 이상 빠른 흡착속도를 보이며 유효확산계수도 20배 이상 높았다. 컬럼통액 실험결과 활성탄소섬유의 흡착용량은 활성탄에 비해 10배 이상으로 나타났다. 유해성 유기 오염물질 10종을 포함한 조제수를 자연여과방식으로 50 L씩 처리한 결과 2단에서 이들 유기성 오염물질을 완전히 제거하여 활성탄에 비하여 수처리 효율이 훨씬 높은 결과를 보였다.

• 한국세라믹학회지
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• 제41권8호
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• pp.599-604
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• 2004

무선 이동통신 산업에서 소형화와 RF모듈을 구현하기 위해 저온 동시 소성 세라믹(LTCC)기술이 부각되고 있다. LTCC용 재료는 90$0^{\circ}C$ 이하의 온도에서 소성이 되어야 한다 본 연구는 BaO-N $d_2$ $O_3$-Ti $O_2$ (BNT：20∼40wt%) 세라믹과 L $a_2$ $O_3$- $B_2$ $O_3$-Ti $O_2$ (LBT：80∼60wt%) 유리를 혼합하여 유리를 결정화시킴으로, 나타나는 부수적인 효과를 얻고자 하였다. 이에 소결 거동, 결정상 분석, 상대밀도 그리고 유전특성을 평가하였다 80wt% 유리의 첨가는 90%에 가까운 상대밀도를 갖는 복합체로서 15에 가까운 유전율과 10000GHz의 품질계수와 같은 우수한 유전특성을 보였다. 이와 같은 결과는 유리 결정화를 이용하여 LTCC용 유전체에 적용될 수 있는 가능성을 부여하였다.