• KSBB Journal
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• 제18권2호
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• pp.111-116
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• 2003

하수 소화 슬러지에 pH제어를 통해 메탄발생 박테리아의 활성을 저하시키는 방법으로 수소발생에 관한 실험을 실시하였다. 반응조는 2 L 운전용적으로 혐기상태로 운전하였으며 37$\pm$1$^{\circ}C$로 항온 유지하였다. pH제어는 IN NaOH를 간헐적으로 주입하였으며 연속적인 운전조작은 가스발생이 나타난 후부터 시작하였다. 슬러지의 유실을 방지하는 방법으로 PVA계 친수성 재질의 담체를 사용한 결과 PVA담체는 혐기성 미생물의 성장 시 최적의 환경을 제공하고 기질과 미생물간의 물질전달이 우수한 담체임을 확인할 수 있었다 한편 슬러지에 유무기 복합 고분자를 투입하는 방법으로 입상화 슬러지를 제조시켜 반응조에 투입하였을 때 밀도를 가진 슬러지는 고농도의 미생물유지가 가능하였다고 판단된다. 입상화 슬러지는 초기의 전형적인 혐기성색깔인 검정색에서 회색으로 변화하였으며 입경분포는 1.5~2.0 mm 정도이었다. 최대 바이오가스 생산량은 380 ml/L/hr였으며 수소가스조성은 50%에 달하였다. 입상화 슬러지는 슬러지의 유실을 방지함으로써 고농도의 미생물 유지가 가능하다고 판단된다.

• Composites Research
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• 제30권6호
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• pp.416-421
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• 2017

CFRP와 금속간의 접합공정이 개선된 구조용 접착제가 제조되었다. 구조용 접착제에 대한 경화시간, 기지재료의 표면상태 그리고 접착제의 양에 따른 최적의 접합공정 조건을 랩쉐어 실험을 통하여 파악하였다. 적합한 접합조건을 확인하기 위해 이종재료간의 접합 파단면 상태를 반사현미경을 이용하여 평가하였다. 이종재료간 접합력 향상을 위해 접착제의 개선뿐만 아니라 CFRP의 표면처리 또한 중요하였다. 구조용 접착제의 경우 180도 조건에 20분의 경화온도 조건이 최적이였으며, CFRP의 표면 처리에 따라 접합특성이 향상됨을 확인하였다. 이종재료 간 접합을 위해 구조용 접착제의 양은 $1.5{\times}10^{-3}g/mm^2$ 조건일 때 최적이었다. 접합공정의 개선 및 최적화를 통해 기존의 접착력 대비 10% 이상의 물성 강화를 나타냄을 확인하였다.

• 한국의류학회지
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• 제38권3호
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• pp.372-385
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• 2014

Lignin is an abundant natural polymer in the biosphere and second only to cellulose; however, it is under-utilized and considered a waste. In this study, lignin was fabricated into nanofibers via electrospinning. The critical parameters that affected the electrospinnability and morphology of the resulting fibers were examined with the aim to utilize lignin as a resource for a new textile material. Poly(vinyl alcohol) (PVA) was added as a carrier polymer to facilitate the fiber formation of lignin, and the electrospun fibers were deposited on polyester (PET) nonwoven substrate. Eleven lignin/PVA hybrid solutions with a different lignin to PVA mass ratio were prepared and then electrospun to find an optimum concentration. Lignin nano-fibers were electrospun under a variety of conditions such as various feed rates, needle gauges, electric voltage, and tip-to-collector distances in order to find an optimum spinning condition. We found that the optimum concentration for electrospinning was a 5wt% PVA precursor solution upon the addition of lignin with the mass ratio of PVA:lignin=1:5.6. The viscosity of the lignin/PVA hybrid solution was determined as an important parameter that affected the electrospinning process; in addition, the interrelation between the viscosity of hybrid solution and the electrospinnability was examined. The solution viscosity increased with lignin loading, but exhibited a shear thinning behavior beyond a certain concentration that resulted in needle clogging. A steep increase in viscosity was also noted when the electrospun system started to form fibers. Consequently, the viscosity range to produce bead-free lignin nanofibers was revealed. The energy dispersive X-ray analysis confirmed that lignin remained after being transformed into nanofibers. The results indicate the possibility of developing a new fiber material that utilizes biomass with resulting fibers that can be applied to various applications such as filtration to wound dressing.

• 복합신소재구조학회 논문집
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• 제2권3호
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• pp.12-17
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• 2011

본 논문은 노후교량바닥판 대체용으로서 하이브리드 GFRP-강재 바닥판의 휨거동을 구조적 거동특성을 기술하고 있다. 하이브리드 GFRP-강재 바닥판의 구조적 특성을 조사하기 위해 정적하중의 실험적 연구를 수행하였다. 하이브리드 바닥판의 파괴모드는 초기항복을 지나서 연성거동을 나타내었다. 결과는 유한요소프로그램 ANSYS의 값과 비교하였다. 제안된 하이브리드 바닥판이 교량적용에 유용함을 확인하였다. 하이브리드 바닥판의 두께는 유사한 휨 강성을 갖는 완전복합신소재 바닥판께와 비교하였을 때 감소될 수 있었다.

• 대한치과의사협회지
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• 제56권3호
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• pp.167-174
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• 2018

The development of dental materials has widened the scope of materials by changes in processing methods. CAD/CAM processing enables the use of zirconia as a dental material. Recent esthetic materials development has been made. For aesthetic purposes, a block for CAD/CAM processing by mixing polymer and ceramic materials are fabricated. However there is no guideline of how these materials should be used in actual clinical practice. Mechanical properties, wear and clinical studies were reviewed.

• 한국막학회:학술대회논문집
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• 한국막학회 2003년도 The 4th Korea-Italy Workshop
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• pp.37-40
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• 2003

Mesoporous zeolite - heteropolyacid-polymer hybrid membrane was prepared by sol-gel processes to make a proton conducting membrane. The crystallinity of mesoporous zeolite in composite membrane was increased with contents of heteropolyacid. Proton conductivity obtained from impedance measurements increases with contents of heteropolyacid, about 10$^{-3}$ S/cm in ca. 1.5 Wt% heteropolyacid.

• 한국고분자학회지:고분자과학과기술
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• 제21권5호
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• pp.447-458
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• 2010

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.143.2-143.2
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• 2010

Therefore, with this development assignment we'd like to develop the hybrid system combining 800W DMFC (Direct Methanol Fuel Cell) and 1.6kW of Lithium secondary battery pack which can be applied to the most common small cart. a scooter, to secure the development capability of hundreds of Watts DMFC, the high-capacity Lithium secondary battery pack, the technology of BMS (Battery Management System) and the development technology of hybrid system. DMFC, in fact, has lower energy efficiency than PEMFC (Polymer Electrolyte Membrane Fuel Cell); however, it has several advantages in terms of fuel storage and use. It is pretty easy to be stored and used without any additional colling and heating devices because of its insensitive liquid methanol to temperature. In conclusion, DMFC system is the most suitable device for small mobile vehicles.

• Macromolecular Research
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• 제17권12호
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• pp.950-955
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• 2009

The physical and rheological properties of thermoplasticized irradiation-crosslinked polyethylene foam using supercritical methanol treatment were investigated by GPC, FTIR, DSC, WAXS, DMTA and UDS. The polyethylene foam was selectively decrosslinked into thermoplasticized polyethylene in an appropriate supercritical methanol condition without any undesirable side reactions such as oxidation and disproportionation. The thermoplasticization was promoted with increasing reaction temperature to reach completion above $380^{\circ}C$. The supercritical reaction condition affected the crystallization behavior, and mechanical and rheological properties of the decrosslinked polyethylene foam, but not its crystallographic structure or crystallinity.

• Macromolecular Research
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• 제16권5호
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• pp.399-403
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• 2008

Monodisperse, micron-sized, hybrid particles having a core-shell structure were prepared by coating the surface of poly(methyl methacrylate)(PMMA) microspheres with silica and by copolymerizing acrylamide (AAm) to supply the hydrogen bonding effect by means of the amide groups. Tetraethoxysilane (TEOS) was then slowly dropped onto the medium under certain conditions. Because of the hydrogen bonding between the amide of the PMMA particles and the hydroxyl group of the hydrolyzed silanol, a silica shell was generated on the PMMA core particles. The morphology of the hybrid particles was investigated with transmission (TEM) and scanning (SEM) electron microscopy as a function of the medium conditions and the amount of TEOS. Improved thermal properties were observed by TGA analysis.