• 한국전기전자재료학회논문지
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• 제17권3호
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• pp.272-277
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• 2004

The primary aim of this study is to investigate new semi-abrasive free slurry including acid colloidal silica and hydrogen peroxide for copper chemical-mechanical planarization (CMP). In general, slurry for copper CMP consists of colloidal silica as an abrasive, organic acid as a complex-forming agent, hydrogen peroxide as an oxidizing agent, a film forming agent, a pH control agent and several additives. We developed new semi-abrasive free slurry (SAFS) including below 0.5％ acid colloidal silica. We evaluated additives as stabilizers for hydrogen peroxide as well as accelerators in tantalum nitride CMP process. We also estimated dispersion stability and Zeta potential of the acid colloidal silica with additives. The extent of enhancement in tantalum nitride CMP was verified through anelectrochemical test. This approach may be useful for the application of single and first step copper CMP slurry with one package system.

• Toxicological Research
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• 제14권4호
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• pp.507-513
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• 1998

The purpose of this study was to clarify the effect of silica on cytosolic free calcium mobilization and cell injury in primary cultured rat hepatocytes. Cytosolic free calcium concentration ([Ca$^{2+}$]) was measured employing calcium sensitive fluorescent dye, Fura-2 / AM, and cell injury was evaluated by determination of cellular ATP contents. Silica increased [Ca$^{2+}$], in a concentration-dependent manner in hepatocytes (10$^{-5}$ ~10$^{-2}$ M). Silica caused a biphasic increase in [Ca$^{2+}$], which was composed of an initial rapid rise and following sustained phase. $Ca^{2+}$ removal from the medium resulted in abolishment of initial and sustained phase of silica (10$^{-2}$ M)-induced [Ca$^{2+}$], in hepatocytes. The pretreatment with nifedipine (1 $\mu$M) attenuated silica-induced [Ca$^{2+}$], increases. Silica decreased cellular ATP contents in a dose-dependent manner. This silica-induced cell injury was attenuated by the pretreatment with EGTA (100 $\mu$M) and nifedipine (1 $\mu$M). This study suggests that the elevation of [Ca$^{2+}$], caused by silica may be due mainly to influx through a plasma membrane $Ca^{2+}$ channel and hepatotoxicity by silica relate with alteration of calcium homeostasis.ium homeostasis.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 센서 박막재료 반도체 세라믹
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• pp.158-161
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• 2003

The primary aim of this study is to investigate new semi-abrasive free slurry including acid colloidal silica and hydrogen peroxide for copper chemical-mechanical planarization (CMP). In general, slurry for copper CMP consists of colloidal silica as an abrasive, organic acid as a complex-forming agent, hydrogen peroxide as an oxidizing agent, a film forming agent, a pH control agent and several additives. We developed new semi-abrasive free slurry (SAFS) including below 0.5% acid colloidal silica. We evaluated additives as stabilizers for hydrogen peroxide as well as accelerators in tantalum nitride CMP process. We also estimated dispersion stability and Zeta potential of the acid colloidal silica with additives. The extent of enhancement in tantalum nitride CMP was verified through anelectrochemical test. This approach may be useful for the application of single and first step copper CMP slurry with one package system.

• Tuberculosis and Respiratory Diseases
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• 제39권2호
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• pp.131-140
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• 1992

유리규산과 자연산 석탄분진의 투여량과 관찰기간에 따른 폐조직과 hydroxyproline 량의 변화를 알아보기 위하여 대조군의 흰쥐에는 생리식염수 0.5ml를 기관지내에 주입하였고 실험군에는 생리식염수 0.5ml에 자연산석탄분진과 유리규산분진이 각각 10 mg, 30 mg, 50 mg씩 함유되도록 혼탁액을 만들어 이를 대조군과 같은 방법으로 주입한후 3주째와 20주째에 실험동물을 도살하여 젖은폐의 무게, 폐조직의 hydroxyproline량 그리고 폐의 조직학적 변화를 관찰한 바 아래와 같은 결과를 얻었다. 1) 자연산석탄분진 10 mg과 30 mg 투여군의 3주째를 제외한 모든 실험군의 젖은폐의 무게는 대조군에 비하여 유의하게 증가하였고(p<0.05), 유리규산 분진투여군에서는 20주째에 같은량의 자연산석탄분진을 투여한 군에 비하여 그리고 같은량의 유리규산분진을 투여한 군에서는 3주째에 비하여 20주째 젖은폐의 무게가 현저히 증가하였다(p<0.05). 2) 자연산석탄분진과 유리규산분진을 투여한 실험각군의 hydroxyproline 20주째에 대조군에 비하여, 그리고 동일한 분진의 같은량을 투여한 군에서는 3주째에 비하여 20주째 유의하게 증가하였으며(p<0.05), 유리규산분진 30 mg과 50 mg 투여군은 20주째에 같은량의 자연산석탄분진 투여한 군에 비하여 현저하게 증가하였다(p<0.05). 3) 분진의 투여량과 관찰기간이 같을때는 자연산석탄분진 투여군에 비하여 유리규산분진투여군에서 폐포간질과 폐포강내에 다형핵 백혈구, 섬유아세포, 대식세포가 증가하였고 폐포강내 삼출액이 관찰되었다. 진폐성결절은 3주째에 유리규산분진 30 mg과 50 mg 투여군에서만 관찰된 반면 20주째에는 모든 실험군에서 관찰되었다. 이상의 결과로 폐조직내 hydroxyproline 량의 증가와 진폐성 결절의 형성은 분진을 투여한 초기보다 후기에 현저하였고 자연산석탄분진보다 유리규산분진투여시 조기에 진폐증이 발생됨을 경험하였다.

• Bulletin of the Korean Chemical Society
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• 제31권4호
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• pp.981-983
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• 2010

The condensation of several aromatic/heteroaromatic aldehydes with 2-aminothiophenol catalyzed by silica sulfuric acid under microwave irradiation afforded 2-arylbenzothiazoles in high yields and short reaction times under solvent-free conditions. The major advantages of the present method are good yields, ecofriendly, reusable catalyst, mild and solvent-free reaction conditions.

• Bulletin of the Korean Chemical Society
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• 제33권7호
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• pp.2149-2155
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• 2012

A metal-free and efficient procedure for the oxidation of alcohols into the corresponding carbonyl compounds has been described using ammonium nitrate in the presence of silica sulfuric acid under mild and heterogeneous conditions. The use of non-toxic and inexpensive materials, simple and clean work-up, short reaction times and good yields of the products are among the advantages of this method.

• Bulletin of the Korean Chemical Society
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• 제25권2호
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• pp.325-327
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• 2004

• 대한화학회지
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• 제45권6호
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• pp.546-548
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• 2001

클로로술폰산을 실리카겔과 반응시키면 실리카겔 표면에 황산이 공유결합으로 고정된 실리카황산을 얻게 된다. 무용매 조건하에서 마이크로웨이브를 쪼여주면서 실리카 황산과 젖은 $SiO_2$를 함께 사용하게 되면 아세탈을 화합물로 변화시키는 효과적인 탈아세탈 시약으로 사용할 수 있다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2010년도 춘계 학술대회 제22권1호
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• pp.107-108
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• 2010

본 연구에서는 실리캬 흄 대체재로써 SFFB를 사용한 고강도 콘크리트 인장부재의 인장강성 특성에 대한 실험결과를 제시한다. 본 연구는 60 및 80MPa의 압축강도를 갖는 고강도 콘크리트에서 고가의 실리캬 흄을 SFFB로 대체 가능성을 평가하는데 목적이 있다. 실험결과, 60 및 80MPa의 고강도 콘크리트 배합에서 실리캬 흄을 대체한 SFFB를 사용한 인장부재의 균열 및 하중거동 특성은 실리캬 흄을 사용한 인장 부재와 대등한 성능을 보였다.

• 센서학회지
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• 제16권1호
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• pp.77-83
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• 2007

Nanoporous silica aerogels with various surface modifiers were prepared by ambient drying process. Tetraethylorthosilicate (TEOS) were used a raw material. Ambient drying process for various surface modifier was studied in the point of view of a crack-free monolith and thin films and low cost. Various kinds of surface modifiers like as hexamethyldisilazane (HMDSZ), trimethlychlorosilane (TMCS), methlytriethoxylsilane (MTES), and methlytrimethoxysilane (MTMS) were studied in order to enhance hydrophobicity for the silica aerogel. Surface modified aerogels were evaluated by FT-IR, TG, BET, SEM and wetting angle measurement. Homogeneous and crack-free aerogels were obtained by modifying the HMDSZ and the TMCS. However silica xerogel was obtained when modified with MTMS, MTES.