• 방사선산업학회지
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• 제6권1호
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• pp.89-94
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• 2012

Three-dimensional network hydrogels were prepared by ${\gamma}$-irradiation of aqueous solutions of poly(vinyl alcohol) (PVA) and glycerol (Gly). Oven-drying was used to measure the gel fraction (G), hydration (H) or swelling behavior (S) of the prepared hydrogels. This study made a hypothesis that hydrogen bonds due to addition of glycerol and change of dry states such as freeze-drying (FD), room-drying (RD) and oven-drying (OD) acts on the G, H, and S. Interesting results on the hydrogen bonding effect in the prepared hydrogels are monitored at different drying conditions. The FD samples have a higher G values with increase in glycerol content as compared with the OD and RD samples. The formation of strong hydrogen bonding network among Gly molecules and hydrogel matrix was considered as the main driving force, resulting in the changes in the G, H, and S of the hydrogels under different drying conditions.

• 접착 및 계면
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• 제12권1호
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• pp.1-10
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• 2011

자동화된 반응 열량계를 이용하여 중합비율을 관찰하면서 blockiness가 다른 PVOH를 이용하여 VAE 에멀젼을 합성하였다. 입자 분포도를 관찰 결과 단량체와 물과 비율에 따른 일정한 그라프트율은 없었다. 초기 단량체-물의 비율이 낮은 곳에서 겔 효과가 관찰되었다. 또한 입자 분포는 넓고 이중 피크가 관찰되었다. 지속적으로 제한적으로 응징집되면서 입자성장이 이루어지는 것이 관찰되었다. 이것은 제한적인 응집현상과 사슬이 PVOH로 그라프팅되어 발생한 결과로 판단된다.

• Macromolecular Research
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• 제16권3호
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• pp.247-252
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• 2008

Lithium gel electrolytes based on a mixed polymer matrix consisting of poly(vinylidenefluoride-hexafluoropropylene) (PVDF-HFP) and cyanoresin type M (CRM) were prepared using an in situ blending process. The CRM used in this study was a copolymer of cyanoethyl pullulan and cyanoethyl poly(vinyl alcohol) (PVA) with a mole ratio of 1:1. The mixed plasticizer was ethylene carbonate (EC) and propylene carbonate (PC) with a volume ratio of 1:1. In this study, the presence of PVDF in the electrolytes helps to form a dimensionally stable film over a broad composition range, and decreases the viscosity. In addition, it provides better rheological properties that are suitable for the extrusion of thin films. However, the presence of HFP has a positive effect on generating an amorphous domain in a crystalline PVDF structure. The ionic conductivity of the polymer electrolytes was investigated in the range 298-333 K. The introduction of CRM into the PVDF-HFP/$LiPF_6$, complex produced a PVDF-HFP/CRM/$LiPF_6$ complex with a higher ionic conductivity and improved thermal stability and dynamic mechanical properties than a simple PVDF-HFP/$LiPF_6$, complex.

• 한국응용과학기술학회지
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• 제37권2호
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• pp.260-267
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• 2020

본 연구에서는 "이온젤" 이라고 불리는 고분자 기반의 PVA(polyvinyl alcohol) 기반의 고체 전해질에 이온성 액체 BMIMBF4 (1-buthyl-3-methylimidazolium tetrafluoroborate)를 첨가하여 제조한 전고체 전해질과 활성탄소와 금속유기골격체 복합재료 기반의 전극 재료를 이용하여 슈퍼커패시터를 제작하였으며, 유기골격체의 유 무에 따른 전기화학적 특성을 분석하여 보았다. 슈퍼커패시터의 전기화학적 특성은 순환전압전류법(CV), 전기화학적 임피던스 분광법(EIS) 및 전정류 충·방전법(GCD)을 통하여 비교 및 분석하여 보았다. 그 결과로, 금속유기골격체가 함유되지 않은 슈퍼커패시터의 전기용량값은 380 F/g 으로 확인 할 수 있었고, 이 값은 금속유기골격체를 첨가하였을 때 340 F/g로 감소하는 현상을 확인할 수 있었다. 이러한 결과로 1 wt%의 금속유기골격체의 함유량은 전기화학적 특성 감소에 영향을 주는 것으로 사료되며 이러한 결과를 바탕으로 금속유기골격체의 첨가량을 최적화 할 필요가 있다고 판단된다.

• 생명과학회지
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• 제30권7호
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• pp.614-624
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• 2020

최근 next-generation sequencing technology의 발달로 유전체 분석 사례는 증가하고 있으나, 단감에 있어 적용 가능한 Single Nucleotide Polymorphism (SNP) 마커 및 적용 결과는 거의 없는 실정이다. 이에 우리나라 고유 떫은감 5품종으로부터 개발된 SNP primer 들을 단감 품종에 적용하여 사용 가능성을 검증하고자 수행하였다. Jung 등에 의해 개발된 19개 SNP primer들의 PCR 조건을 확인 한 후 본 실험의 전기영동 방식으로는 분석이 매우 어려웠던 8개의 primer를 제외한 11개의 SNP primer들을 최종 선발하였다. 1, 2차 검증을 통해 최종 선발된 11개의 SNP primer 들을 76품종 및 계통(불완전단감 20, 완전단감 30, 완전떫은감 20, 불완전떫은감 6)에 적용한 결과 38품종 및 계통(불완전단감 8, 완전단감 18, 완전떫은감 9, 불완전떫은감 3품종)은 각 품종 및 계통 간 구분을 할 수가 없었다. 그러나 최종 선발된 11개의 SNP primer 들을 신품종에 적용한 결과만를 보면 '감누리', '단누리', '홍추'와 '자미시', '미감조생'을 동시에 구분할 수 있어 단감 신품종 판별을 위한 특이적 마커로 사용될 수 있을 것으로 판단된다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XII)
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• pp.327-330
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• 2003

본 연구에서는 수질정화능력이 뛰어난 것으로 알려진 D회사의 광합성세균 및 그 겔제품의 탈질특성을 알아 보았고, 실제적용을 위한 해수농도 (3.5% NaCl)에서의 이용 가능성 여부도 알아보았다. 각 염농도별(0, 1, 2, 3.5%) 평균 최대 비증식속도는 각각 0.22, 0.22, 0.20, $0.11\;h^{-1}$ 로 계산되었다. 또한, 낮은 pH에서 배양할 경우 성장에 상당한 영향을 받음을 알 수 있었다. 고정화 비-드의 경우, 최대 $N_2$생성율$(dN_2/dt)$는 각각 0.09-0.10 (직경 0.7cm), 0.09-0.11(직경 1.0cm) ml/h로 계산되었고, 비-드 당 평균 $N_2$생성율$(dN_2/dt)$은 각각 5, $5.5\;{\mu}l$/h/bead이었다. D 광합성세균과 탈질미생물간의 두 균 사이에는 어떠한 길항작용도 없었다.

• Environmental Engineering Research
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• 제10권5호
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• pp.227-238
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• 2005

The characteristics of nitrogen removal by the free cell and the immobilized cell of R. capsulatus were investigated. Denitrification by R. capsulatus cells resulted in reduction of ORP with the rapid depletion of DO and the increase of pH. Without accumulation of nitrite, the removal efficiencies of ${NO_3}^-$-N for the free cell and the immobilized cell were 99.1 and 99.3%, respectively. During the three-month experiment of goldfish breeding equipped with a water-purification biofilter, the average values of pH and total cell numbers present in an aquarium were not significantly different between water-purification system and the control. The average concentrations of ${NH_4}^+$-N and ${PO_4}^{2-}$-P in water-purification system were relatively low, compared to that in the control. Goldfish died at $11^{th}$, $16^{th}$, $43^{rd}$, and $67^{th}$ days in the control, while goldfish died at $10^{th}$, $20^{th}$, and $39^{th}$ days in the water-purification system. On the days of goldfish's death, the total concentrations of nitrogenous compounds except for ${NO_2}^--N$ were higher than those on the other days of the experiment, especially with the concentrations of ${NH_4}^+$-N ranging from 7.4 to 13.5 mg/L. The water-purification system also showed the less turbidity of water with more active movement of goldfish than the control. PVA gel beads showed almost the full denitrifying ability even after the long-term experiment. As a result, the water-purification system was effective to remove nitrogenous compounds with better survival of goldfish.

• International Journal of Advanced Culture Technology
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• 제3권1호
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• pp.21-30
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• 2015

Ceramic foams are prepared as positive images corresponding to a plastic foam structure which exhibits high porosities (85-90%). This structure makes the ceramic foams attractive as a catalyst in a dry reforming process, because it could reduce a high pressure drop problem. This problem causes low mass and heat transfers in the process. Furthermore, the reactants would shortly contact to catalyst surface, thus low conversion could occur. Therefore, this research addressed the preparation of dry reforming catalysts using a sol-gel catalyst preparation via a polymeric sponge method. The specific objectives of this work are to investigate the effects of polymer foam structure (such as porosity, pore sizes, and cell characteristics) on a catalyst performance and to observe the influences of catalyst preparation parameters to yield a replica of the original structure of polymeric foam. To accomplish these objectives industrial waste foams, polyurethane (PU) and polyvinyl alcohol (PVA) foams, were used as a polymeric template. Results indicated that the porosity of the polyurethane and polyvinyl alcohol foams were about 99% and 97%. Their average cell sizes were approximate 200 and 50 micrometres, respectively. The cell characteristics of polymer foams exhibited the character of a high permeability material that can be able to dip with ceramic slurry, which was synthesized with various viscosities, during a catalyst preparation step. Next, morphology of ceramic foams was explored using scanning electron microscopy (SEM), and catalyst properties, such as; temperature profile of catalyst reduction, metal dispersion, and surface area, were also characterized by $H_2-TPR$ and $H_2-TPD$ techniques, and BET, respectively. From the results, it was found that metal-particle dispersion was relatively high about 5.89%, whereas the surface area of ceramic foam catalysts was $64.52m^2/g$. Finally, the catalytic behaviour toward hydrogen production through the dry reforming of methane using a fixed-bed reactor was evaluated under certain operating conditions. The approaches from this research provide a direction for further improvement of marketable environmental friendly catalyst production.