• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.160-160
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• 2011

In the present work, $TiO_2$ fiilms supported by porous silica gel with high surface area synthesized by atomic layer deposition(ALD). Porous structure of silica substrate could be maintained even after deposit large amount of $TiO_2$ (500 cycles of ALD process), suggesting the differential growth mode of $TiO_2$ on top surface and inside the pore. All the $TiO_2$-covered silica samples showed improved MB adsorption abilities, comparing to bare one. In addition, when silica surface was covered with $TiO_2$ films, MB adsorption capacity was almost fully recovered by re-annealing process (500$^{\circ}C$, for 1 hr, in ambient pressure), whereas MB adsorption capacity of bare silica was decreased after re-heaing process. FT-IR study demonstrated that $TiO_2$ film could prevent deposition of surface-bound intermediate species during thermal decomposition of adsorbed MB molecules. Photocatalytic activity of $TiO_2$/silica sample was also investigated.

• 한국재료학회지
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• 제11권7호
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• pp.603-608
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• 2001

졸겔법에 의해 제조된$ MO-SiO_2$(M=Zn, Sn, In, Ag, Ni)이성분계 실리카 겔에서 금속이온의 종류에 따른 실리카 구조의 변화를 XRD, FT-lR, $^{29}$Si-NMR로 분석하였다. XRD peak을 관찰한 결과 $Ag-SiO_2$겔에서 $AgNO_3$의 부분적인 재결정화가 나타났지만, 첨가된 금속이온과 실리카 매트릭스의 결합에 의한 결정상은 관찰되지 않았다. FT-IR 분석결과 첨가되는 금속이온 중 Zn, Sn, In은 부분적으로 Si-O-M의 결합형태를 이루어 Si-O-Si 대칭 진동에 의한 흡수 peak의 위치를 변화시켰다. $^{29}$Si-NMR 관찰에 의해 Zn, Sn, In등의 금속이온은 실리카의 저온 졸겔 반응에 영향을 미치지 않고 불완전한 네트워크를 갖는 선형적 실리카 구조 내에서 비가교 산소와 결합하며 존재하였다. Ag, Ni는 실리카 네트워크가 형성되는 과정에서 실리카 형성을 위한 졸겔반응의 촉매로서 작용하여, 이러한 금속이온이 첨가된 실리카 네트워크는 보다 치밀한 구조적 특성을 나타내었다.

• 한국세라믹학회지
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• 제25권5호
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• pp.479-487
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• 1988

In this study we studied the function of Glycerol as a DCCA(Drying Control Chemical Additives) in the preparation of silica bulk glas through Sol-Gel method. We used TEOS(Tetra Ethyl Ortho Silicate) and maintained the mixing ratio of TEOS : H2O : EtOH : HCI as 1 : 4 : 4 : 0.0007(mol) and varied glycerol input quantity from 0.1vol% considering the ethnaol input quantity as 100vol%. We investigated the changes from Sol-Gel Synthetic solutions to the glass using DT-TG, FT-IR and other instruments. The results obtained from this experiment showed that the dried gels made from the synthetic solutions containing 0.1-1.0vol% of glycerol were easily heat-treated up to 85$0^{\circ}C$ so that transparant bulk silica glass was prepared.

• 한국세라믹학회지
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• 제34권9호
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• pp.941-948
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• 1997

CuCl nanocrystallites dispersed nonlinear optical silica and borosilicate glasses were fabricated by sol-gel process. CuCl powder was dissolved in TEOS(Si(OC2H5)4) and TMB((CH3O)3B), precursors of silica and borosilicate glasses, with ethanol, water and HCl, and precipitated through the heat treatment in the matrix glass. The optical properties of CuCl doped glasses were measured using the spectrophotometer at room temperature and low temperature(77K); Z1, 2 and Z3 exciton peaks from the absorption spectra, were observed at about 370 nm and 380 nm, respectively. The average radius of nanocrystallites, calculated from the blue shift of Z3 excitons, was measured according to annealing temperature and time. The precipitation temperature of CuCl nanocrystallites was decreased when boron was added to silica glass. Increase of annealing temperature and time made average radius of nanocrystallites saturated about 2 nm.

• 한국결정성장학회지
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• 제13권2호
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• pp.73-78
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• 2003

Tetraethyl orthosilicate (TEOS)로부터 유도된 동결건조 실리카 젤의 기공구조에 미치는 하소온도의 영향이 질소 등온흡착 및 수은압입법에 의하여 조사되었다. 동결건조물은 다소간의 마이크로기공을 함유하고 있었으나 주로 4~6nm 크기의 매크로기공 및 7~20$\mu\textrm{m}$ 크기의 매크로기공으로 구성되어 있었다. 하소온도의 증가에 따른 기공구조변화는 치밀화 정도에 의존하였다.

• 산업기술연구
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• 제26권A호
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• pp.199-205
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• 2006

Ozone alone and catalytic ozone processes were introduced for treatment of humic acid, which is representative refractory organic compound. The treatment efficiencies of humic acid in each process were analyzed in pH variation, DOC removal, and $UV_{254}$ decrease. Mn loaded GAC catalyst was prepared by loading potassium permanganate onto the granular activated carbon surface. BCM-GAC and BCM-Silica gel catalyst were prepared by BCM. $UV_{254}$ decrease in all processes was comparatively high with efficiency over 87%. DOC removal in ozone/GAC process was the highest with 78%, and removal rates for other processes followed the order ozone/BCM-GAC(62%) > ozone/BCM-silica gel(45%) > ozone/silica gel(43%) > ozone/Mn Loaded GAC(42%) > ozone alone(37%).

• KSBB Journal
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• 제17권4호
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• pp.365-369
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• 2002

수용성 형태로 존재하는 융합 페리틴을 정제함에 있어서 실리카 분말을 이용한 전처리 공정은 전체 정제 공정효율 증가에 기여하였다. 전처리 공정을 통해 정제된 융합 페리틴의 순도를 높이기 위해 젤 여과 크로마토그래피를 통해 보다 정제된 응합 페리틴을 얻을 수 있었다. 이렇게 정제된 융합 페리틴의 철분결합능력을 분석해본결과 320 moles $F_{H}+F_{L}$ mole로 활성이 우수함을 알 수 있었으며, 분자량 분석을 통해 융합페리틴(40 k dalton)은 trimer와 monomer형태로 존재함을 확인할 수 있었다

• 대한기계학회논문집B
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• 제31권2호
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• pp.116-124
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• 2007

An adsorption chiller is expected to have high energy-efficiency in utilizing the waste heat exhausted from a process. The objective of this paper is to investigate the performance of silica gel-water adsorption chiller from the cycle simulation and to provide a guideline for design of the adsorption chiller. The effect of cycle time, inlet temperature and water flow rate on the cooling capacity and COP is quantified during the cycle operation. It is found that the performance of adsorption chiller is more sensitive to the change of inlet water temperature rather than the water flow rate. It is concluded that the COP is 0.57 in the standard conditions(hot water $80^{\circ}C$, cooling water $30^{\circ}C$, chilled water inlet temperatures $14^{\circ}C$ and cycle time 420sec).

• 한국환경보건학회지
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• 제6권1호
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• pp.23-26
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• 1979

한국에서 사용하고 있는 carbamate계 살충제의 사용율(%)은 1968년경에는 2.1%인데 비해서 현재는 급증되고 있는 실정에 있다. 따라서 이로 인한 자타살 사건, 환경오염, 살포시 급만성 중독 등의 사고가 빈번히 발생하고 있는 동시에 법화학적 분석에도 많은 문제점이 되두되고 있으므로 1차적으로 시판되고 있는 carbamate계 살충제를 thin layer chromatography에 의해서 성분의 분리 확인 시험을 실시한 결과 1) Silica Gel G-60 및 Silica Gel F-254에서 적합하였고 2) 전개용매는 chloroform: benzeneP: carbontetra chloride (60:30:25), cyclohexane: acetone (80:20), cyclohexane:acetone(70:30), ether:hexane(80:20)에서 9종의 살충제가 잘 분리되었으며 3) UV light (2537 ${\AA}$) 및 2.6-dibromoquinone-4-chlorimide는 전개는 Rf치를 육안으로 구분하는데 가장 양호하였고 4) Carbamate계 살충제 중 Bux-2와 Sevin은 Silica Gel G-60에서 UV light (2537 ${\AA}$)에서 특이한 청보라 및 청색형광을 관찰할 수 있었다. 5) 이상의 결과를 보아 법화학적 시료중에 함유된 카바메이트계 농약의 분석은 가능할 것이며 또한 이 방법의 적용이 현재의 실정으로서는 적합한 것으로 사료되는 바이다.

• Bulletin of the Korean Chemical Society
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• 제21권8호
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• pp.817-822
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• 2000

Crack-free hard coating siIica films were prepared by sol-gel processfrom twokinds of silicon alkoxide (tetra-ethoxysilane and methyltrimethoxysilane) and two kinds of alcohol (methanol and isopropyl alcohol) with an acid catalyst,acetic acid. A silicate framework of the precursor solution was investigated by infrared spectros-copy (IR) in the process of hydrolysis and condensation. Theextent of the condensation in the intermediates was elucidated by gel permeation chromatography (GPC) and 29Si-NMR spectroscopy. The hard coating films werecharacterized by IR,scanning electron microscope (SEM), thermo gravimetric analyzer (TGA) and dif-ferential scanning calroimeter (DSC). The synthetic condition for the crack-free and transparent silica film for-mation was optimized interms of starting materials for the precursor solution as well as preparation method of the silica film.