Multi-walled carbon nanotube reinforced epoxy composites were fabricated using shear mixing and sonication. The mechanical, viscoelastic, thermal, and electrical properties of the fabricated specimens were measured and evaluated. From the images and the results of the measurements of tensile strengths, the specimens having 0.6 wt% nanotube content showed better dispersion and higher strength than those of the other specimens. The Young's moduli of the specimens increased as the nanotube filler content was increased in the matrix. As the concentrations of nanotubes filler were increased in the composite specimens, their storage and loss moduli also tended to increase. The specimen having a nanotube filler content of 0.6 wt% showed higher thermal conductivity than that of the other specimens. On the other hand, in the measurement of thermal expansion, specimens having 0.4 and 0.6 wt% filler contents showed a lower value than that of the other specimens. The electrical conductivities also increased with increasing content of nanotube filler. Based on the measured and evaluated properties of the composites, it is believed that the simple and efficient fabrication process used in this study was sufficient to obtain improved properties in the specimens.

Mussels are stubborn organism attached to solid substrate by byssus threads and caused operational problems in utility of power generating stations. Sole and combined usage of ultrasonic (28 kHz- and 42 kHz- frequencies) and hydrogen peroxide (H2O2) has studied for control of blue mussel larvae and adult stage in seawater condition. A theoretical wo rking model using disinfection (Chick and Watson type) approaches is presented based on helpful results of experiments. This study also demonstrate that the combined treatment (ultra-sonication with H2O2) is overall highly efficient than individual treatment would, but on the basis of exposure time, the ultra-sonication was the most efficient among them. Therefore the development of sole and combined technique might be effective practical mitigation strategy against mussel attachment for water handling facilities.

The interaction between Agrobacterium and soybean has been studied at the transcriptome level but not at the metabolic level. However, it is necessary to investigate the difference in metabolites between susceptible and non-susceptible cultivars for high efficiency transformation. We investigated the difference in metabolites from sonicated soybean cotyledons of Korean cultivars and Bert cultivar. To identify difference in metabolites, sonicated extracts were analysed by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR/MS). The soybean cultivars were classified by susceptibility using green fluorescent protein expression. We found a difference in metabolites between the high susceptible and low susceptible cultivars. The FT-ICR/MS experimental m/z data of different metabolites were compared with theoretical m/z in KNApSAcK database. The candidate list was made using KNApSAcK and focused on phenolic compounds. These candidate metabolites are speculated to influence factors in the interaction. This list of candidates may be useful to investigate the interaction between Agrobacterium and plants to increase transformation efficiency.

NIST 표준시료인 SRM 2710(Montana Soil)을 대상으로, 중금속의 지화학적 존재형태 연구에 일반적으로 적용되는 Tessier 연속추출법과 최근 소개된 초음파연속추출법을 적용 및 비교하여 오염 토양 내 중금속의 효율적 분석방법을 제시하고자 하였다. As, Cd, Cu, Pb, Zn의 총함량을 USEPA Method 3050B, KBSI Method, 초음파 추출법을 적용하여 분석한 결과, 모두 공인 분석값에 가까운 값으로 측정되었다. Tessier 연속추출법과 초음파 연속추출법의 비교 결과, 원소별 및 단계별 추출 양상과 추출효율이 두 방법 모두 거의 동일한 것으로 나타났다. 초음파 연속추출에는 총 3시간 정도 소요되었으며, 기존의 Tessier 연속추출법의 12시간 정도와 비교할 때 크게 단축되었다. 유기오염 시료의 전처리법으로 흔히 사용되는 초음파 추출법은 비교적 짧은 시간 내 추출이 이루어지고, 고온의 가열이 필요치 않으며, 시료에 직접 강한 파장을 주어 추출하기 때문에 비교적 높은 추출효율을 보이는 효과적인 방법이라 할 수 있다.

The objectives of this study have been carried out to investigate the solubilization of municipal sewage sludge by single and dual frequency ultrasonic pretreatment, and the methane production characteristics of pretreated sewage sludge by specific methanogenic activity test for sewage sludge reduction. The waste activated sludge was collected from thickened tank of Suyoung sewage treatment plant in Busan city, and its concentration was adjusted to 1.0% total solids. Ultrasonic frequency was varied 15, 20, 15+20 kHz, and acoustic density was used a maximum 176W/L. The dual frequency ultrasonic pretreatment was found to be more effective than single frequency ultrasonic in the solubilization rate and methane production. The SCODCr/TCODCr rate were 15.2%, 13.9%, 17.0% with single frequency of 15 kHz, 20 kHz, dual frequency of 15+20 kHz, respectively. The application of dual frequency ultrasound for sewage sludge pretreatment can be interest for sewage treatment plants having problems in sludge treatment and disposal.

The effects of sonication and vacuum infiltration on transformation efficiency was investigated by using immature embryos of Korean wheat as explants. Two Agrobacterium tumefaciens strains, KYRT1 and EHA105, carrying pCAMBIA 1305.1 were used. Transformation efficiency was demonstrated by the detection of β-glucu-ronidase (GUS) activity. GUS expression showed clear difference among Korean wheat cultivars. Geurumil showed higher GUS expression efficiency 79.1~% compared with other cultivars. The effects of the duration of vacuum infiltration and sonication treatment showed a tendency high GUS expression efficiency by their combination. In comparison with other Agrobacterium strains, KYRT1 showed high efficiency in most Korean cultivars.

A aqueous solution of malodorants (i.e., n-valeraldehyde, n-valeric- acid, 2-methylisoborneol, and trimethylamine) was exposed to 200kHz ultrasound with a power of 6.0W/cm2 per unit volume in a sonochemical reactor under room temperature and atmospheric pressure condition. The concentration of malodorants decreased with irradiation time, indicating pseudo-first-order kinetics. The removal efficiency of malodorants was about from 50% to 96% decomposed after 90 minutes sonication. At the deodorization, it was determined by triangle odor bag(TOB) method for odor sensory measurement, and it indicated that over 60% of relative odors were deodorized with degradation by the sonication.