• 한국세라믹학회지
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• 제41권9호
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• pp.715-721
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• 2004

합성 수산화아파타이트(HAp)와 바인더로서 젤라틴(GEL)을 사용하여 공침법으로 조성비가 서로 다른 HAp/GEL 균질복 합체 4종을 제조하였고, 이 균질복합체를 냉간정수압법으로 성형한 후 공기중에서 여러조건으로 소결하였다. HAp/GEL composite의 소결체는 XRD 및 FT-IR로 결정성 및 구조를 조사하였고, 또한 소결시편은 만능재료시험기(UTM)로 압축강도를 측정하였으며, 파단된 소결시편의 표면은 SEM으로 관찰하였다 HAp/GEL composite는 120$0^{\circ}C$에서 3시간 소결하였을 경우 부분적인 $\alpha$, $\beta$-tricalcium phosphate로 상전이가 일어났다. 소결체의 기공률은 1.2-30.2% 범위였고, 소결시편의 압축강도는 16.2-60.1㎫ 범위의 값을 나타냄으로써 기공율에 비해 높은 강도를 나타내었다.

• 한국동물학회지
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• 제16권1호
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• pp.67-77
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• 1973

한국산 초파리(Drosophila melanogaster)의 starch gel 영동상을 조사하기 위하여 춘천, 진주, 신촌(서울), 대전의 초파리 4계통을 starch gel media를 사용하여 벤드의 분포, 염색강도 및 이동도를 비교 검토한 결과는 다음과 같다. 1) 춘천, 진주, 신촌(서울)의 3계통은 벤드의 수와 분포, 염색강도, 이동도가 다 같이 심한 변이를 나타내고 있는데 반하여 대전계통은 변이가 거의 없다. 2) 이러한 전기영동상의 차이는 대전 계통의 초파리 집단이 ADH구성에 관하여 동질적(homogeneous)이고 다른 3계통의 집단은 이질적(heterogeneous)이라는 것을 암시하고 있다. 3) 전기영동상이 4계통의 초파리에서 다 같이 암$\\cdot$수에 따라 차이를 보이고 있는데 이것은 설명하기 매우 어려운 문제로서 장차 분석 검토할 필요가 있다고 본다. 4) Starch gel media가 cellulose acetate media보다 해상력이 월등하다는 것이 재확인 되고 있다. 5) Agar gel이나 acrylamide gel 같은 다른 영동 media를 써서 ADH의 전기영동 실험을 하여 starch gel media를 사용한 본 실험의 결과와 비교하는 것과 ADH에 관한 유전적 분석이 시급히 요구되는 앞으로의 과제이다.

• Bulletin of the Korean Chemical Society
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• 제24권10호
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• pp.1485-1489
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• 2003

The gelation for di-(2-ethylhexyl) phthalate (DEHP)-plasticized poly(vinyl chloride) was studied by measuring time-resolved small-angle X-ray scattering (SAXS) and a flow of the solutions in test tube. It was found that for the gelation there were three regimes. At Regime I, the solution rapidly changed to a gel, and the SAXS intensity showed a peak and the peak intensity increased, keeping the peak angle constant. Applying the SAXS intensity to the kinetic analysis of the liquid-liquid phase separation, it was revealed that the spinodal decomposition proceeded to develop a periodic length of 29.9 nanometer in size, a hydrogen-bonding-type association in polymer rich phase followed, and then it induced fast gelation rate. At Regime II, the gelation slowly occurred and the SAXS intensity was not observed, suggesting that a homogeneous gel network was formed by a hydrogen-bonding. At regime III, the solution was a homogeneous sol.

• KSBB Journal
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• 제18권1호
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• pp.35-38
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• 2003

양수 내에 존재하는 총 단백질을 이차원 전기영동을 이용하여 분리 분석하였고, gradient gel을 이용하여 양수 내에 소량으로 존재하는 미세 단백질까지 분리하였다. 양수 내에는 고농도로 존재하는 단백질이 있는데 이것이 serum albumin precursor임을 확인하였고, 8-18% gradient gel의 이용으로 분해능(resolution)이 향상되어 미세 단백질을 분리 분석할 수 있었다. 이차원 전기영동 후 MALDI-TOF를 이용하여 단백질을 identification하여 기존의 양수 protein database에 존재하는 단백질을 확인하였고, 존재하지 않는 새로운 단백질을 분리 분석하였다.

• 한국응용과학기술학회지
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• 제26권3호
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• pp.288-296
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• 2009

In this study, the silica-based hybrid material with high barrier property was prepared by incorporating ethylene-vinyl alcohol (EVOH) copolymer, which has been utilized as packaging materials due to its superior gas permeation resistance, during sol-gel process. In preparation of this EVOH/$SiO_2$ hybrid coating materials, the (3-glycidoxy-propyl)-trimethoxysilane (GPTMS) as a silane coupling agent was employed to promote interfacial adhesion between organic and inorganic phases. As confirmed from FT-IR analysis, the physical interaction between two phases was improved due to the increased hydrogen bonding, resulting in homogeneous microstructure with dispersion of nano-sized silica particles. However, depending on the range of content of added silane coupling agent (GPTMS), micro-phase separated microstructure in the hybrid could be observed due to insufficient interfacial attraction or possibility of polymerization reaction of epoxide ring in GPTMS. The oxygen barrier property of the mono-layer coated BOPP (biaxially oriented polypropylene) film was examined for the hybrids containing various GPTMS contents. Consequently, it is revealed that GPTMS should be used in an optimum level of content to produce the high barrier EVOH/$SiO_2$ hybrid material with an improved optical transparency and homogeneous phase morphology.

• 한국전기전자재료학회논문지
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• 제17권9호
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• pp.953-959
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• 2004

BaTiO$_3$ powder has been applied in so much electronic ceramics. Therefore, as recent, the method to add or coat additive will be needed BaTiO$_3$ powder. As a kind of the method, the coating of BaTiO$_3$ powder was considered. In this study, during BaTiO$_3$ powder was coated by BaTiO$_3$ sol, gelation path was experimented. Standard coating condition was set for homogeneous coating. The phase of the gel was deferent by gelation path. It was confirmed the amorphous gel was made in BaTiO$_3$ phase easily at low temperature. In the amorphous gel, particle growth was shown at 900$^{\circ}C$, because crystallization temperature was low. The optimal ratio of sol and powder was at 10 vol% for the homogeneous coating.

• 대한화학회지
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• 제42권2호
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• pp.156-160
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• 1998

화학겔로써 대표적인 실리카겔과 아마이드겔의 겔화(gelation)과정을 살펴보고 라텍스 입자를 추적자로 사용하는 광산란 실험을 통해 이들의 구조와 화학적 성질을 고찰하여 보았다. 표준입자(standard particle)로 쓰이는 라텍스 입자를 추적자로 사용하여 입자들의 병진운동(translational diffusion)을 고려함으로서 겔의 내부공간크기를 확인하고 겔과 입자표면과의 화학적 상호작용을 고려하였다. 실리카겔은 아마이드 겔보다 규칙적인 겔구조를 나타내는 것으로 사료되며 표면이 카르복실기를 갖는 입자는 실리카 겔과 엉킴(aggregation)현상을 나타냄을 관측하였다. 불균일(heterogeneity)한 겔의 고조확인을 위한 광산란법을 비에르고딕(non-ergodic)이론에 기초한 통계적인 방법을 통해 접근하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.814-819
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• 2000

The progress in the field of electronic materials has been especially significant for applications involving a range of electrical properties. Its importance is increasing with the increasing demand for integrated circuits. The sol-gel technique has been used for many years, and the metal alkoxides have featured prominently as source materials. The method consist of making a homogeneous solution of the component metal alkoxides in a suitable solvent, usually the parent alcohol; and then causing the hydrolysis under controlled conditions to produce a gel containing the hydrated metal oxide. The gel is then dried, and fired to produce a ceramic or glassy material at a temperature much lower than that required by the conventional melting process. This project consists of important theoretical considerations, processing techniques and applications related to electrophoresis derived thin films. In the electrophoretic process a metal alkoxide solution is gelled through hydrolysis-polymerization and converted the gel thin layer to an oxide by heating at relatively low temperatures.

• 한국세라믹학회지
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• 제34권11호
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• pp.1187-1197
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• 1997

Dry gel composed of primary particles more homogeneous than starting boehmite powder was prepared by dispersing and gelling the boehmite powder. The transformation temperatures of boehmite powder, dry gel seeded with 0, 1, 3, 5 wt% $\alpha$-Al2O3, and ball milled gel were 1192$^{\circ}C$, 1184$^{\circ}C$, 1141$^{\circ}C$, 1119$^{\circ}C$, 1117$^{\circ}C$, and 1106$^{\circ}C$, respectively. Sintering behavior of dry gel without seed was similar to that of boehmite powder, but the sintered density of dry gel was improved as much as 10%~15% than boehmite powder. In the case of dry gel seeded with 5 wt% $\alpha$-Al2O3, sintering behavior was much improved. The relative density of the gel seeded with 5 wt% $\alpha$-Al2O3 was 96% when sintered at 140$0^{\circ}C$ for 1h. On the other hand, ball milling of the non-seeded sol for 48h resulted in the relative density of 97% when sintered at 130$0^{\circ}C$ for 1h. The size and amount of $\alpha$-Al2O3 particles added by ball milling were 0.107 ${\mu}{\textrm}{m}$ and 0.5 wt%.

• 미생물학회지
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• 제13권2호
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• pp.71-80
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• 1975

The neurotoxin of Clostridium botulinum type B was purified from a liquid culture. The purification steps consist of ammonium sulfate precipitation of whole culture, treatment of Polymin P(0.15%, v/v), gel filtration on Sephadex G-100 at pH5.6 and DEAE-Sephadex charomatography at pH8.0. The procedure recovered 17% of the toxin assayed in the starting culture. The toxin was homogeneous by sodium dodecyl sulfate(SDS)-polyacrylamide gel electrophoresis and had a molecular weight of 163,000. Subunits of 106,000 and 56,000 molecular weight were found when purified toxin was treated with a disulfide-reducing agent and electro phoresed on SDS-polyacrylamide gels.