• 상하수도학회지
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• 제23권6호
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• pp.703-709
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• 2009

In this study, an artificial-waterway experiment was conducted, using an attachment plate, on which algae from Nanakita river was placed, to examine the influence exerted by the variation of the dissolved-silicon concentration on the river periphyton. As a result, the variation of the dissolved-silicon concentration was found to exert an influence on the density of the adhesion diatom, and the mole ratio limits of the silica were about $Si/P{\fallingdotseq}182$ and $Si/N{\fallingdotseq}16.4$ or less. Moreover, the mole ratio that is necessary for proliferation was found to be larger than the value of the oceanic algae. Senedesmus sp. and Ankistrodesmus sp., which used silica in adhesion chlorophyta, received the influence of the silicon concentration strongly, and the twowere found to be superior in the environment, making silica a restriction factor.

• 한국식품위생안전성학회지
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• 제17권1호
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• pp.15-19
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• 2002

The objectives of this study were to investigate the change of silicon, cations and anions dissolved in water before and after thawing, and analyzed what the white-colored precipitate (WP) farmed after thawing was composed of. The silicon concentration that has been changed might have been compared with the weight of WP under water-free state. The major component of WP has been approved to be a silicon, while calsium was only a little contained. As the weight of WP has been nearly equal to the reduced silicon concentration, the weight of its could be changeable calculated by silica (SiO$_2$) molecular weight. Therefore, WP could have been presumed to be a silica. The more silicon concentration was increased, the more weight of silicon was increased. Except for the sample "C", the amounts of cations and anions could be found to be unchangeable nearly. As a result of that, WP has been apparent to be silica itself while most of ions (excluded with Si) of any others were not changed.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제52권12호
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• pp.579-585
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• 2003

Recently the utilization of the ozone dissolved de-ionized water(DI-O3 water) in semiconductor wet cleaning process to replace the conventional RCA methods has been studied. In this paper, we propose the water-electrode type ozone generator which has the ozone gas characteristics of the high concentration and high purity to produce the high concentration DI-O3 water for the silicon wafer surface cleaning process. The ozone generator has the dual dielectric tube structure of silent discharge type and the water is both used to electrode and cooling water. We investigate the performance of the proposed ozone generator which has the design goal of the concentration of 7[wt%] and ozone generation quantity of 6[g/hr] at flow rate of 1[$\ell$/min). The experiment results show that the water electrode type ozone generator has the characteristics of 8.48[wt%] of concentration, 8.08[g/hr] of generation quantity and 76.2[g/kWh] of yield and it's possible to use the proposed ozone generator for the DI-O3 water cleaning process of silicon wafer surface.

• 센서학회지
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• 제6권3호
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• pp.221-227
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• 1997

Pd/NiCr 게이트 MISFET 센서는 변압기 절연유중 용존수소를 감지하기 위해 제조되었다. 센서의 안정성과 고농도 감지성의 향상을 위해 Pd/NiCr 2중 촉매 금속 게이트가 사용되었다. 수소유입에 의한 게이트 전압의 드리프트를 줄이기 위해, 2개의 FET 게이트 절연층을 실리콘 산화막과 실리콘 질화막의 2중 구조로 하였다. Pd/NiCr 게이트 MISFET 센서의 수소 감응 감도는 Pd/Pt 게이트 MISFET 센서의 감도에 비해 약 0.5배이나, 안정성이 좋고, 1000 ppm까지의 고농도까지 측정할 수 있었다.

• 자원환경지질
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• 제42권4호
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• pp.335-342
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• 2009

감마선을 조사(照射)하거나 조사하지 않은 두 경우의 Bacillus Subtilis를 대상으로 하여 박테리아 세포 붕괴(lysis)를 유도한 후 방출된 유기 분자가 pH 7 조건에서 석영 용해 속도에 미치는 영향을 조사하였다. 시간이 경과하며 석영과 박테리아 혼합 슬러리에서 용존 유기탄소(dissolved organic carbon; DOC) 함량이 증가하였으며 이는 박테리아 투입량과 대체적으로 비례하는 것으로 보아 박테리아 세포 붕괴의 결과인 것으로 판단되었다. 방사선을 조사하지 않은 박테리아를 투입하였을 경우, 시간이 경과하며 박테리아를 투입하지 않은 화학적 비교 슬러리에 비해 높은 함량의 규소가 용출되어 나왔다. DOC 함량과 용해되어 나온 규소 함량간에 나타난 좋은 상관관계는 규소 용출의 원인이 박테리아 세포 붕괴에 의해 방출된 DOC에서 비롯되었음을 나타낸다. 한편 방사선을 조사한 박테리아의 세포 붕괴 산물은 방사선을 조사하지 않은 경우에 비하여 단위 DOC 함량당 매우 높은 농도의 규소를 용출시켰다. 이 때 관찰되는 규소 용출은 방사선이 조사되었을 때 교란된 박테리아 내부의 유기 분자가 방사선을 조사하지 않은 박테리아에 비하여 석영을 보다 효과적으로 용해할 수 있는 유기 분자로 변화하였기 때문으로 판단된다. 이 결과는 고준위 방사성 폐기물 처 분장에서 누출된 핵종이 지표 생태계에 도달하는데 소요되는 시간을 예측할 때 처분장 주변 대수층 암석의 풍화 속도 촉진에 미치는 박테리아 세포 붕괴의 영향을 고려해야 함을 나타낸다.

• Korean Chemical Engineering Research
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• 제55권5호
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• pp.711-717
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• 2017

A fundamental study was conducted on the dissolution of North Korean magnesite using hydrochloric acid to understand the dissolution behavior of the magnesium and impurities. The influence of the acid concentration, particle size of the magnesite, reaction temperature, and pulp density on the dissolution of magnesium, iron, calcium, aluminum, and silicon dioxide was studied. The experimental results showed that 98.5% of magnesium, 86.9% of iron, 87.3% of calcium, 23.6% of aluminum, and 20.4% of silicon dioxide were dissolved when magnesite particle sizes within the range of $75{\sim}105{\mu}m$ were reacted using 3 M HCl solution under 6% pulp density at 363 K for 3 h. The residues that remained after the dissolution were silicon dioxide, talc, and clinochlore.

• Bulletin of the Korean Chemical Society
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• 제22권2호
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• pp.205-209
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• 2001

Uniformly-doped silicon thin films were fabricated by ion beam sputter deposition. The thin films had four levels of copper dopant concentration ranging between 1 ${\times}$1019 and 1 ${\times}$ 1021 atoms/cm3 . Concentrations of Copper dopants were determined by the isotope dilution inductively coupled plasma mass spectrometry (ICP-MS) to provide certified reference data for the quantitative surface analysis by secondary ion mass spectrometry (SIMS). The copper-doped thin films were dissolved in a mixture of 1 M HF and 3 M HNO3 spiked with appropriate amounts of 65 Cu. For an accurate isotope ratio determination, both the detector dead time and the mass discrimination were appropriately corrected and isobaric interference from SiAr molecular ions was avoided by a careful sample pretreatment. An analyte recovery efficiency was obtained for the Cu spiked samples to evaluate accuracy of the method. Uncertainty of the determined copper concentrations, estimated following the EURACHEM Guide, was less than 4%, and detection limit of this method was 5.58 ${\times}$ 1016 atoms/cm3.

• 연구논문집
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• 통권33호
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• pp.99-109
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• 2003

Recently the utilization of the ozone dissolved de-ionized water(DIW-$O_3$) in semiconductor wet cleaning process and photoresist stripping process to replace the conventional sulfuric acid and hydro peroxide mixture(SPM) method has been studied. In this paper, we propose the water-electrode type ozone generator which has the characteristics of the high concentration and purity to produce the high concentration DIW-$O_3$ for the photoresist strip process in the semiconductor fabrication. The proposed ozone generator has the dual dielectric tube structure of silent discharge type and the water is both used to electrode and cooling water. Through this study, we obtained the results of the 10.3 wt% of ozone gas concentration at the oxygen gas of 0.5 [liter/min.] and the DIW-$O_3$ concentration of 79.5 ppm.. Through the photoresist stripping test using the produced DIW-$O_3$, we confirmed that the photoresist coated on the silicon wafer was removed effectively in the 12 minutes.

• 반도체디스플레이기술학회지
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• 제4권4호
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• pp.19-26
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• 2005

The process optimization of ozone concentration and half life time was investigated in ultra pure water and alkaline solutions for the wet cleaning of silicon wafer surface at room temperature. In the ultra pure water,. the maximum concentration (35 ppm) of ozone was measured at oxygen flow rate of 3 liters/min and ozone generator power over 60%. The half life time of ozone increased at lower power of ozone generator. Additive gases such as $N_2$ and $CO_2$ were added to increase the concentration and half life time of ozone. Although the maximum ozone concentration was higher with the addition of $N_2$ gas, a longer half life time was observed with the addition of $CO_2$. When $NH_4OH$ of 0.05 or 0.10 vol% was added in DI water, the pH of the solution was around 10. The addition of ozone resulted in the half life time less than 1 min. In order to maintain high pH and ozone concentration, ozone was continuously supplied in 0.05 vol% ammonia solutions. 3 ppm of ozone was dissolved in ammonia solutions. The static contact angle of silicon wafer surface became hydrophilic. The particle removal was possible alkaline ozone solutions. The organic contamination can be removed by ozonated ultra pure water and then alkaline solution containing ozone can remove the particles on silicon surface at room temperature.

• Korean Chemical Engineering Research
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• 제54권4호
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• pp.459-464
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• 2016

본 연구에서는 리튬이온 전지용 실리콘 음극소재의 사이클 안정성 및 율속 특성 향상을 위해 다공성 실리콘/탄소 복합소재의 전기화학적 특성을 조사하였다. 나노 실리카 제조는 스토버 방법을 사용하고 교반 속도, 교반 온도 및 $NH_3$/TEOS 비율을 조절 하여 100~500 nm 크기의 구형 실리카를 합성하였다. 구형 나노 실리카의 마그네슘 열환원과 산처리 과정을 통해 다공성 실리콘을 얻고, 제조된 다공성 실리콘에 Phenolic resin을 탄소전구체로 사용하여 최종적으로 다공성 실리콘/탄소 활물질을 합성하였다. 또한 $LiPF_6$ (EC:DMC:EMC=1:1:1 vol%) 전해액에서 다공성 실리콘/탄소 음극소재의 충 방전, 순환전압 전류, 임피던스 테스트 등의 전기화학적 특성을 조사 하였다. 다공성 실리콘/탄소 복합소재의 음극활물질로서 코인 전지의 성능을 조사한 결과 초기용량 및 40사이클 용량 보존율은 각각 2,006 mAh/g, 55.4%를 나타내었다.