• Analytical Science and Technology
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• v.21 no.5
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• pp.397-402
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• 2008

Uranium dioxide was dissolved with nitric acid and a trace amount of HF. The analytical conditions of a spectrophotometer were investigated to determine a trace amount of silicon in the uranium matrices without a separation process. The effects of a trace amount of HF on the determination of silicon were examined. Boric acid was used to eliminate HF the interference in the colorimetric process. The recovery of silicon in the presence of a trace amount of HF in uranium solutions with or without saturated boric acid was $103.3{\pm}0.8$ and $76.6{\pm}6.8%$, respectively. The amount of saturated boric acid did not affect the recovery of the silicon. Therefore it was possible for this procedure to measure a trace amount of silicon in a uranium matrix without a separation by a UV-VIS spectrophotometry.

• Horticultural Science & Technology
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• v.31 no.2
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• pp.153-158
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• 2013

This research was carried out to investigate silicon (Si) uptake levels by six potted plant species from a nutrient solution supplemented with $K_2SiO_3$. Uniform rooted plants of Dendranthema grandiflorum Ramat., Spathiphyllum patinii N.E. BR., Kalanchoe blossfeldiana, Hedera helix L., Dianthus caryophyllus L., and Euphorbia pulcherrima Willd. were grown in 350 mL boxes, one plant per box, containing a nutrient solution supplemented with either 0, 2.7, or 5.4 mM Si as $K_2SiO_3$. The nutrient solution in each container was adjusted to EC $1.5mS{\cdot}cm^{-1}$ and pH 5.6. The solution in each container was aerated by an 1 m-long polyethylene tube, all connected to a vacuum pump. After 15 days of cultivation in a glasshouse Si contents in the roots and shoots were measured using the colorimetric molybdate method and amount of remaining Si in the nutrient solution was measured using the ICP-AES to calculate the amount of absorption. A simple regression analysis was performed to observe the changes in Si contents in the roots and shoots as affected by concentration of Si supplied to the solution. Among the six species tested, carnation had the greatest and poinsettia the lowest tissue levels of Si concentration in the root, whereas carnation had the greatest and kalanchoe the lowest tissue levels of Si concentration in the shoot. Based on the Si content in the whole plant, Si uptake levels by poinsettia, kalanchoe, and chrysanthemum were low, whereas those by spathiphyllum were intermediate, and those of English ivy and carnation were high. These results indicated that the uptake level of Si by the plant vary depending on plant species.

• Proceedings of the Korean Vacuum Society Conference
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• 2008.08a
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• pp.69-69
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• 2008

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.343-344
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• 2006

방향성 규소강판을 tape-wound core 형태로 제작하여 가공방법에 따른 자기적 특성을 조사 하였다. 그 결과 곡률반경이 40mm인 시료에서 보자력(Hc)과 포화자속밀도(Bs)는 우수한 값을 나타내었고, 보자력은 0.02Oe, 포화자속밀도는 1.85T 이었다. 현재 국내에서 생산되고 있는 방향성 규소강판의 자속밀도값 보다 우수한 값을 나타내었다. 본 연구로부터 방향성 규소강판을 이용하여 권자심을 제작할 때 도입되는 탄성변형에 대한 대책의 중요성과 코어 소재의 가공방법이 자기적 특성에 미치는 영향을 통해 고효율 방향성 규소강판 개발의 가능성을 확인하였다.

• Journal of the Korean Vacuum Society
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• v.5 no.2
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• pp.133-138
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• 1996

Epitaxial cubic silicon carbide films have been deposited on carbonized Si(001) substrates using the single precursor 1, 3-disilabutane in the temperature range 900-$1000^{\circ}C$ under high vacuum conditions. The films grown were characterized by in situ RHEED, XPS, XRD, x-ray pole figure, SEM, and TEM. The results show that epitaxial cubic SiC films with smooth morphology and good crystallinity were formed in this temperature range. The single precursor 1, 3-disilabutane has been found suitable for the epitaxial growth of cubic SiC on Si(001) substrates.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.2
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• pp.61-67
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• 2005

In this study a new growing method of silicon nitride whiskers in the inside of large pores made intentionally during the sintering was conducted. Pore size, pore vol%, and nitrogen pressure were used as experimental variables. Silicon nitride whiskers were well grown in the inside of pores with low pore vol% range from 14 to 27 but not grown with high pore vol% such as 39 and 50. On the other hand, pore size and nitrogen pressure did not have any influence on the whisker growth. Therefore the most important factor to grow silicon nitride whisker in the inside of large pores during sintering was to make pores isolated or closed.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.11
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• pp.1251-1256
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• 2015

In this paper, the processing conditions of the amorphous silicon film growth were investigated the effect in forming the HSG-Si on the surface of the storage electrode. As a result, when the amorphous silicon film phosphorus concentration is greater than $5.5{\pm}0.1E19atoms/cm^3$, HSG-Si is not formed correctly and showed the concentration dependency of HSG formation. Also, the optimum condition of the phosphorus concentration for amorphous silicon and HSG thickness are $4.5E19atoms/cm^3$ and $450{\AA}$, respectively, because of the HSG thickness over the $500{\AA}$ create to bit failure according to a short of the electrodes and the electrode.

• Korean Journal of Materials Research
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• v.8 no.6
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• pp.551-559
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• 1998

장경비가 큰 탄화규소를 탄소와 규소간의 고온연소반응으로 제조하기 위하여 공정변수에 따른 연소거동과 미세조직의 변화를 조사하였다. 연소합성된 생성물은 주로 $\beta$-SiC이며 연소반응이 충분히 진행되지 못하였을 경우에는 미량의 잔류 반응물과 $\alpha$-SiC가 관찰되었다. 생성된 탄화규소의 평균입도는 약 5$\mu\textrm{m}$로 작았으며, $1300^{\circ}C$ 이상의 예열 조건에서 장경비가 30이상인 탄화규소를 합성할 수 있었다. 압분 강도가 69MPa인 분말의 성형체에서 평균 연소 온도와 평균 전파 속도는 각각 약 $1425^{\circ}C$와 2.1mm/sec 범위이며, 연소 온도는 흑연 분말을 사용하였을 경우가 탄소 섬유를 사용한 경우보다 약 $10^{\circ}C$ 높았다. 연소 반응을 임의로 중단시킨 시편의 계면을 EDX와 Auger 전자 현미경으로 분석한 결과 상호 확산층이 관찰되지 않았다. 이는 탄화규조의 연소합성이 용해-석출 모델에 의하여 진행됨을 시사한다. 예열 온도에 따른 연소 반응 중의 온도 분포를 유한 요소법으로 해석함으로써 $2500^{\circ}C$의 초기 연소 개시 온도에 대하여 예열 온도 $300^{\circ}C$에서는 연소파가 거의 전파할 수 없으며 예열 온도가 $1300^{\circ}C$에서는 시료 내부에 자체 전파가 가능한 $2000^{\circ}C$이상의 온도 구역이 존재함을 알았다.

• Journal of the Korean Chemical Society
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• v.41 no.10
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• pp.541-546
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• 1997

Manganese dioxide may react with silicon tetrachloride to form manganese(Ⅳ) oxodichloride which reacts subsequently with another molecule of silicon tetrachloride leading to manganese tetrachloride eventually in chlorinated solvents. This in situ generated manganese(Ⅳ) oxodichloride or manganese tetrachloride were found to be very effective for the chlorination of a wide variety of alcohols to the corresponding chlorides. Primary, secondary and benzylic alcohols were converted into corresponding chlorides when treated with silicon tetrachloride in the presence of manganese dioxide at room temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.239-240
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• 2007

변압기 코어소재로 사용하는 방향성 규소강판의 가공 방법에 따른 물성을 조사하기 위하여 테이프 와인딩 코어 형태, 곡률반경을 20, 30, 40mm로 하여 토로이달 형태 변압기 시료의 B-H 자성 특성을 조사하였다. 곡률반경이 40mm, 높이는 10mm의 비율에서 보자력은 0.02Oe, 포화자속밀도는 0.98, 1.85T으로 보자력(Hc)은 낮고 포화자속일도(Bs)는 제일 큰 값을 나타내었고, 국내에서 생산되고 있는 방향성 규소강판의 자속밀도값 보다 약간 크게 나타났으며, 본 연구로부터 방향성 규소강판을 이용하여 권자심 코어을 제작할 때 고려해야하는 탄성변형에 대한 중요성과 코어 소재의 가공방법이 자기적 특성에 미치는 영향을 고찰하였다. 또한 토로이달 코어형태의 변압기를 설계 제작시 높이와 곡율반경, 가공 방법에 따라 용량, 효율 등이 다르므로 사전에 소재의 물성을 면밀히 검토 후에 전기기기에 적용해야함을 재확인하였다.