• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.17 no.12
• /
• pp.1179-1183
• /
• 2007

Electro-Active paper(EAPap) is a new smart material that has a potential to be used in biomimetic actuator and sensor. It is made by cellulose that is abundant material in nature. EAPap is fascinating with its biodegradability, lightweight, large displacement, high mechanical strength and low actuation voltage. Actuating mechanism of EAPap is known to be the combined effects of ion migration and piezoelectricity. However, the electromechanical actuation mechanisms are not yet to be established. This paper presents the modeling of the actuation behavior of water infused cellulose samples and their composite dielectric constants calculated by Maxwell-Wagner theory. Electro-mechanical forces were calculated using Maxwell stress tensor method. Bending deflection was evaluated from simple beam model and compared with experimental observation, and which result in good correlation with each other.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1994.04a
• /
• pp.276-276
• /
• 1994

지구 환경문제의 하나인 오존충의 파괴는 지구상에 분포되어있는 자외선량을 증가시키는 외에 지금까지 지상에 도달하지 않았던 단파장역의 자외선량의 증가를 초래하여, 이것에 피부암, 백내장등의 발병율 증가등의 건강 피해가 염려된다. 이들 발병기전은 아직 확실치 않으나 에너지가 큰 단파영역의 자외선에 폭로되면 세포내의 물분자의 이온화에 기인되어 발생하는 활성산소종이 막지질, 핵산. 단백질등에 산화적 손상을 가져와 이것에 돌연변이, 세포사를 초래하는 것이 그 원인의 하나라고 생각된다. 본 연구는 자외선 중 UVB의 조사로 인한 장해와 유도단백질을 찾아내어, 자외선의 유해성을 밝히는데 목적을 두었다. UVB를 농도별로 1회 hairless mouse에게 조사하여, 경시적으로 피부를 채취하여, UVB 조사로 인해 유도되는 단백질을 2차 전기영동법을 이용해 관찰하고. 유도단백질이 HSP인지를 면역염색을 통해 밝히고, 유도된 단백질을 protein sequence를 하여, 어떤 단백질인지 밝혔다.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.18 no.11
• /
• pp.1128-1133
• /
• 2008

Cellulose based electroactive paper(EAPap) has been developed as a new smart material due to its advantages of piezoelectricity, large displacement, low power consumption, low cost and flexibility. EAPap can be used for a surface acoustic wave (SAW) device using the piezoelectric property of EAPap, resulting in the cost effective and flexible SAW device. In this paper, inter digit transducer(IDT) structure using lift-off technique with a finger gap of 10mm was used for micro fabrication of the cellulose EAPap SAW devices. The performance of IDT patterned SAW device was characterized by a Network Analyzer. The feasibility of cellulose EAPap as a potential acoustic device was presented and explained.

• Journal of fish pathology
• /
• v.9 no.2
• /
• pp.177-183
• /
• 1996

A new RNA virus isolated from abnormally swimming behavior has caused mortalities in salmonid fish (Oh et al., 1995 a), A reverse transcriptase (RTase) activity of the virus was determined by using poly r(A) : oligo d(T) as templete : primer. This RTase activity was associated with virus particles of buoyant density of 1.16 g/ml. The virus particles in sucrose fractions were enveloped and were about 85 nm diameter with central electron-dense core. The brain and kidney samples of artificially infected fish showed RTase activity. Virus particle associated proteins about 120, 80, 65, 61, 48, 42, 35, 30, 25, 19, and 15 kDa were observed when examined by polyacrylamide gel electrophoresis analysis. This study showed the presence of a new retrovirus in salmonid fish, which tentatively called RVS (Retrovirus of salmonid).

• Applied Biological Chemistry
• /
• v.36 no.1
• /
• pp.1-6
• /
• 1993

Chitinase was induced in rice cell suspension culture with treatment of chitooligosaccharides mixture. Among eleven isozymes found in 10% polysacrylamide gel electropherogram, four isozymes were identified as induced enzymes. Acidic chitinase fraction separated in DEAE-cellulose column chromatography, includes three induced chitinase, while basic fraction contains only one induced isozyme. Treatment of chitooligosaccharides mixture enhanced the contents in both protein and chitinase activity in cell suspension culture media, but increase in chitinase activity was much higher than in protein.

• Journal of the Korean Wood Science and Technology
• /
• v.32 no.4
• /
• pp.58-65
• /
• 2004

This study was performed to investigate the protease activity from fruit body of Sarcodon aspratus and its features. The specific protease activity was increased with the increasing purification steps, 2.62 times by desalting, 17 times by CMC column chromatography, 113.8 times by DEAE-Sephadex A-50 column chromatography, and 728.3 times by Sephadex G-75 column chromatography. Proteases were identified as two different enzymes having different isoelectric points at pH 4.35 (its recovery rate 8%) and pH 4.7 (its recovery rate 3.5%). Those proteases were purified by 3,025 folds and 3,257 folds in terms of specific activity. Two proteases having different isoelectric points had similar enzymatic properties. This protease was estimated to be 43,000 daltons of molecular weights by SDS-PAGE. This protease with optimum pH 4 was almost stable in the pH range of 4~7. Optimal temperature of protease activity was 40 to 50℃, and the protease activity was completely inhibited at 70℃ for 30 min.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1994.04a
• /
• pp.185-185
• /
• 1994

관상동맥은 전기적으로 자극하여도 활동전위가 쉽게 유발되지 않는 조직인데, 이는 세포내의 $Ca^{2+}$에 의해서 활성화되는 $K^{+}$통로때문이라고 여겨지고 있다. 저자들은 단일 이온통로 수준에서 이러한 관상동맥 $K^{+}$ 통로의 성질을 조사하고, 아울러 $K^{+}$ 통로 개방제를 포함한 몇가지 약물이 $K^{+}$ 통로에 미치는 영향을 알아보고자 본 연구를 수행하였다. 막소포는 돼지의 심장에서 관상동맥을 분리하여 균질화 및 원심분리하여 준비하였으며, sucrose 20/30%에 있는 층을 취하여 분주한 후 -7$0^{\circ}C$로 보관하여 사용하였다. 평지방막은 1-palmitoyl, 2-oleoyl-phosphatidyl ethanolamine과 1-palmitoyl, 2-oleoyl phosphatidylcholine (4:1)을 n-decane에 녹인지방액(25mg/m1)을 200 $\mu\textrm{m}$의 구멍에 칠하여 만들었다. 단일 $K^{+}$ 통로는 막소포 (1-5$\mu\textrm{g}$/ml)를 평지방막의한쪽에 추가하고 자석으로 저어 융합이 되도록 하였으며, 통로의 활성은 막의 양쪽에 150 mM KCI, 10 mM HEPES-KOH, 0.5 mM EGTA, 0.6 mM $CaCl_2$ (pH 7.2)로 된용액이 존재하는 상태에서 막전압을 다르게 하며 기록하였다. 단일 이온 통로 전류는 amplifier를 통하여 VCR tape에 녹화하여 후에 분석에 이용하였으며, 동시에 종이기록지에 기록하였다. 단일이온통로 활성의 분석은 pClamp (Ver5.5)를 이용하여 수행하였다. 관상동맥에서 가장 흔히 기록되는 이온통로는 막전압과 $Ca^{2+}$의 농도에 의하여 변하는 $K^{+}$ 통로이었는데 pCa 4.0과 -10 mV에서 초기 활성도(Po)는 0.1에서 0.8까지 다양하였다. 전류와 전압과의 관계는 -60 - +60mV의 전압범위에서 직선형이었다.

• Journal of Korean Society of Environmental Engineers
• /
• v.32 no.1
• /
• pp.87-96
• /
• 2010

The electrode material is one of the factors affecting the power production of microbial fuel cell. In this study, effects of carbon electrode material, thickness and configuration on the power density, biofilm formation and microbial community diversity of microbial fuel cell were investigated. To optimize the anode-cathode electrode assembly, seven lab-scale reactors which had various carbon electrode constructions were operated in continuous mode. Under the steady state condition, the electrode combination of graphite felt (6 mm) with hole showed the highest cell voltage of 238 mV and the coulombic efficiency of 37%. As a result of SEM analysis, the bacteria growing on surface of knitted type of carbon cloth and graphite felt electrode ncreased significantly. The change of dominant species between seeding sludge and biofilm on the surface of anode electrode, microbial analysis with PCR-DGGE showed that the dominant species of seeding sludge are quite different from those of biofilm on the surface of each anode electrode. Especially Geobacter sp., a well known electrochemical bacteria, was found as the dominant species of the electrode combination with graphite felt.

• Journal of the Korean Society for Precision Engineering
• /
• v.28 no.11
• /
• pp.1227-1233
• /
• 2011

Cellulose Electro-Active Paper (EAPap) has been known as a new smart material that is attractive for a bio-mimetic actuator due to its merits in terms of lightweight, dry condition, large displacement output, low actuation voltage and low power consumption. Cellulose EAPap is made by regenerating cellulose and aligning its micro-fibrils. This paper introduces several EAPap materials, which are based on natural cellulose and its hybrid nanocomposites mixed/blended with inorganic functional materials. By chemically bonding and mixing with carbon nanotubes and inorganic nanoparticles, the cellulose EAPap can be a hybrid nanocomposite that has versatile properties and can meet material requirements for many applications. Recent research trend of the cellulose EAPap is introduced in terms of material preparations as well as application devices including actuators, temperature and humidity sensors, biosensors, chemical sensors, and so on. This paper also explains wirelessly driving technology for the cellulose EAPap, which is attractive for bio-mimetic robotics, surveillance and micro-aerial vehicles.