• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.1155-1156
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• 2006

In this paper, we analyzed the effect of EVA Sheet Gel Content depending on curing condition for photovoltaic module. Gel Content was measured by manufacturing Glass/EVA Sheet/Back Sheet scheme at several curing temperature and curing time. And the surface analysis of EVA Sheet depending on process condition could be observed using SEM(Scanning Electron Microscope). Through this experiment, we could confirm that there are differences on Gel Content of EVA Sheet and surface configuration depending on curing temperature and curing time. To find out the optical characteristic dependency on curing condition, Class/EVA Sheet/Glass scheme was fabricated. The optical transmittance of EVA Sheet at visible wavelength was enhanced 5% when compared to Glass/Glass scheme. And the transmittance of $130^{\circ}C$/4min, $110^{\circ}C$/4min, $160^{\circ}C$/6min process condition was higher at ultraviolet wavelength range. These curing conditions could be regarded as the best process for suppression the discoloration speed of EVA Sheet under UV light.

• Bulletin of the Korean Chemical Society
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• 제24권7호
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• pp.943-947
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• 2003

We have studied the migration behavior of single-stranded DNA using capillary gel electrophoresis under various conditions. It was found that optimum electric fields should be less than 150 V/cm for the good tradeoff between the separation time and the resolution. It seems that the gel matrix with the combination of different polymer average molecular weights is important to extend the maximum readable DNA bases. The total gel concentration less than 3.1% in the mixed gel system showed good separation efficiency up to 600 bases. The best result was obtained with the poy(ethylene)oxide (PEO) gel concentration of 1.2% of Mr 8,000,000 and 1.8% of Mr 600,000. We observed that the capillary length between 50 cm to 100 cm (effective length) should be employed for the optimization between the total DNA migration time and the maximum readable length. A trizma base-boric acid-ethlyenediaminetetraacetic acid (EDTA) (TBE) buffer was commonly used for DNA sequencing, but we found that 3-[tris(hydroxymethyl)methyl amino]-1-propane sulfonic acid (TAPS) buffer worked as well for the single-stranded DNA separation. Especially, TAPS buffer showed a good resolution for very short DNA bases (1 to 30 bases).

• 폴리머
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• 제29권1호
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• pp.91-95
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• 2005

화학적 가교와 방사선 가교에 의해 내열특성을 가진 PVA 수화젤을 제조하였다. 제조된 수화젤의 젤화율, 팽윤도와 젤강도 같은 기계적 특성을 측정하였다. 젤화율은 화학적 가교 반응시간과 방사선 조사선량이 증가할수록 증가하였고, 화학적 가교 후에 방사선 가교를 했을 경우에 화학적 가교만 했을 때보다 높은 값을 보였다. 젤강도는 화학적 가교 반응시간이 증가할수록 증가하였고, 방사선 조사선량이 감소할수록 증가하였다. 5시간 화학적 가교만 한수화젤과 화학적 가교 후에 방사선 가교를 한 수화젤이 고온에서의 내열특성이 우수하였다.

• 한국세라믹학회지
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• 제36권9호
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• pp.893-900
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• 1999

Silica films were prepared on Si single crystal substrates by sol-gel process using TEOS as starting materials. Films were fabricated by a spin coating technique. Sol solutions were prepared by varying the compositions of CH3OH, H2O and DMF with fixed molar ratio of TEOS=1, HCl=0.05(mol). Wetting behavior viscosity of solutions gelation time thickness of films and cracking behavior were investigated with the various solution compositions. Wetting behaviors of solutions depended on the solution compositions mixing method and mixing rate. The optimum composition of sol was TEOS : DMF ; CH3OH: H2O :HCl=1:2:4:4:0.05(mol) and the mixing rate of solution was optimized at 1 ml/min. Viscosity of solutions were controlled by choosing a reaction time(elapsed time after mixing) at a room temperature so that we could get up to 800nm thick film The surface roughness was getting poor when thickness of films was thicker than 500nm. Thickness of coated films were increased with decreasing amount of CH3OH. The best surface roughness was obtained at the content of CH3OH 4 mol. The shortest gelation time was obtained with the content of CH3OH 8 mol. Crack-free filkms were fabricated when sintered at 500$^{\circ}C$ for 1 hr with heating rate of 0.6$^{\circ}C$/min.

• 한국세라믹학회지
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• 제26권5호
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• pp.677-681
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• 1989

On the preparation of silica glass by sol-gel process, we used fine powder of silica gel to prevent cracking. In this case, the best condition of silica glass preparation is the contents of 10~40wt% seed and the gelation time of solution in contract. The dried gels conversed to silica glass by heat treatment up to 125$0^{\circ}C$.

• 대한수의학회지
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• 제33권1호
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• pp.81-85
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• 1993

Gel electrophoresis has proven to be one of the most useful of DNA separation and purification. The new technique of pulsed field gel electrophoresis (PFGE) is high resolution separation of large size DNA moleculs. Conventional continuous gel electrophresis can not be separation of large DNA fragments(20~50 k base). Field inversion gel electrophoresis(FIGE) is very useful for large DNA molecules. We have found that a pulse ratio ; 2 : 1, time ; 24hrs., volts ; $10^{volts}/_{cm}$, start ; 0.45sec, end ; 1sec, is most effectively resolves DNA fragment in the 6~50k base.

• 한국세라믹학회지
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• 제28권5호
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• pp.365-372
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• 1991

LAS (lithium aluminosilicate) sol was synthesized using the hydrolysis-condensation reaction of TEOS, chelated Al(OBus)3 and Li-salt with H2O in alcohol (EtOH+2-Propanol) medium. Effects of important reaction parameters on the properties of sol and gel-derived LAS were examined. The crystallization of the sol-gel derived LAS with ${\beta}$-spodumene composition began at ∼600$^{\circ}C$, and a series of polymorphic transformations occurred as temperature was increased to 1100$^{\circ}C$: amorphous LAS\longrightarrowhexagonal LiAl(SiO3)2\longrightarrow${\beta}$-spodumene. Lowering Li content in the gel enhanced densification and retarded the crystallization significantly. Optimum reaction conditions of LAS sol formation for thin coating applications were derived from rheological measurements, and these can be summarized as: H2O/total alkoxides molar ratio=4, pH=∼2.5, and aging time of ∼250h.

• Elastomers and Composites
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• 제54권3호
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• pp.247-251
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• 2019

Two different urethane acrylates (mono-acrylate and di-acrylate) were used to prepare unsaturated polyester-based hybrid gel-coats. The physical properties and surface characteristics of these gel-coats were investigated on the basis of the content and type of urethane acrylate. The set-to-touch time increased and the physical properties (surface hardness and tensile strength) decreased with an increase in the urethane acrylate content. However, the type of urethane acrylate did not affect these parameters. It was found that the optimal urethane acrylate content for the application of unsaturated polyester-based hybrid gel-coats is ~10 wt%.

• 한국식품과학회지
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• 제28권6호
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• pp.1052-1058
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• 1996

쌀 품종별 가공특성에 관한 연구의 일부로 아밀로오스 함량과 gel consistency가 다른 5가지 품종에 대한 노화특성을 조사한 결과는 다음과 같다. Brabender amylograph에 의한 쌀 품종별 호화특성에서는 아밀로오스 함량에 관계없이 hard gel인 품종이 높은 setback 값을 보였다. 45%의 쌀전분 겔을 $20^{\circ}C$에서 저장하면서 0, 1, 2, 3, 5일 후의 rigidity modulus (E)를 측정한 결과 hard gel인 품종의 초기경도가 soft gel에 비해 더 높았는데 고아밀로오스 품종의 경우는 초기 경도에 관계없이 최종경도가 다른 품종들에 비하여 더 높았다. Avrami equation에 의한 쌀전분겔의 노화 특성 연구에서는 고아밀로오스인 수원232호와 San Li Cun이 각각 4.42와 7.94로 작은 시간상수(1/k)값을 나타내 아밀로오스 함량이 높을수록 노화가 더 빠르게 진행되는 것으로 나타났으나 품종별 gel consistency의 차이가 노화속도에 미치는 영향은 일정한 양상을 나타내지 않았다.

• 한국분말재료학회지
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• 제19권6호
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• pp.398-404
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• 2012

This paper describes the spherical ammonium diuranate gel particles which are the intermediated material of the $UO_2$ microsphere for an VHTR(very high temperature reactor) nuclear fuel. The characteristics of the intermediate-ADU gel particles prepared by AWD(ageing, washing, and drying) and FB(fluidized-bed) apparatus were examined and compared in a sol-gel fabrication process. The electrical conductivity of washing filtrate from the FB treating and the surface area of dried-ADU gel particles were higher than those of AWD treating. Also, an internal pore volume in dried-ADU gel particles showed a more decrease in AWD treatment than FB treatment because of decomposition of PVA affected by the washing time. However, the internal microstructures of ADU gel particles were similar regardless of the process variation.