• Macromolecular Research
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• 제15권1호
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• pp.10-16
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• 2007

In this work, we prepared epoxy/BMI composites by using N,N'-bismaleimide-4,4'-diphenylmethane (BMI), epoxy resin (diglycidyl ether of bisphenol-A (DGEBA)), and 4,4'-diamino diphenyl methane (DDM). The thermal properties and water sorption behaviors of the epoxy and BMI composites were investigated. For the epoxy/BMI composites, the glass transition and decomposition temperatures both increased with increasing BMI addition, which indicates the effect of BMI addition on improved thermal stability. The water sorption behaviors were gravi-metrically measured as a function of humidity, temperature, and composition. The diffusion coefficient and water uptake decreased and the activation energy for water diffusion increased with increasing BMI content, indicating that the water sorption in epoxy resin, which causes reliability problems in electronic devices, can be diminished by BMI addition. The water sorption behaviors in the epoxy/BMI composites were interpreted in terms of their chemical and morphological structures.

• Asian Journal of Atmospheric Environment
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• 제5권3호
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• pp.196-203
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• 2011

The main aim of this study is to establish methods of morphological preservation and elemental quantification for individual snow crystals. Individual snow crystals were collected at a height of 20 m above ground level. To stabilize and preserve the original morphologies of the snow crystals, cyanoacrylate, which has been used to fix liquid droplets, was applied (Kasahara et al., 2000). Several different kinds of snow crystals (dendrite, sectored plate, quasi-sectored plate, and hexagonal plate) were successively stabilized using this method. The stabilized snow crystals were pretreated with acetone, and then the elemental components contained in a whole snow crystal were quantified with the Particle Induced X-ray Emission (PIXE) analytical technique. The snow crystal residual composition determined in the present study was dominated by sulfur and mineral components, and the elemental mass showed an apparent crystal size dependence, where the elemental mass gradually decreased as the crystal size increased.

• 한국미생물·생명공학회지
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• 제23권5호
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• pp.580-587
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• 1995

In order to produce the bacteriolytic enzyme, bacterial strains capable of excreting a large amount of the enzyme were screened from the coastal sea water samples in Pusan. The bacterial strain SH-1, which showed the highest activity among 43 bacteriolytic enzyme producing bacteria, was finally selected for further studies. The strain SH-1 was an endospore-forming grampositive rod, and the position of spore was paracentral. These morphological characteristics assigned the isolated strain to the morphological group I classified by Gordon. The fatty acid composition of the bacterial stain was analyzed to be consisted of branched chains of iso-Cn and anteiso-Cn. Based on the percent content of the branched chain (93.85%), the isolates could be identified as a species of Bacillus. According to the experimental results of the API system (API 50CHB & API 20E) the strain was identified as Bacillus subtilis. Numerical texonomy, in which 82 major characters were examined using several species of Bacillus as the standard bacteria, indicated that the strain SH-1 showed 90% similarity to Bacillus subtilis. Thus, the isolated strain SH-1 could be identified as Bacillus subtilis.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 컴퓨터소사이어티 추계학술대회논문집
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• pp.153-156
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• 2003

In this paper, we propose a new scheme for automatic segmentation of the liver in CT images. The proposed scheme is carried out on region of interest(ROI) blocks that include regions of the liver with high probabilities. The ROI approach saves unnecessary computational loss in finding the accurate boundary of the liver. The proposed method utilizes the composition of multi-size morphological filters with a prior knowledge, such as the general location or the approximate intensity of the liver to detect the initial boundary of the liver. Then, we make the gradient image with the weight of the initial liver boundary and segment the liver legion by using an immersion-based waters hed algorithm in the gradient image. finally, the refining process is carried out to acquire a more accurate liver region.

• Journal of Plant Biology
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• 제28권4호
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• pp.305-315
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• 1985

Morphological variations within the species of Scenedesmus in Korea, S. armatus and 2 strains of S. quadricauda were investigated. Taxonomic characters such as length of long spine, ridge, unicell-colony transformation, and colony types were compared. The length of long spine was constant, whereas the distribution of the spine varied with the age of culture. Ridge and short spine in S. armatus occurred constantly, whereas those in S. quadricauda varied with the composition of the media and age of culture. Strains CY-1 and CY-2 showed 6 different colony types in the stationary culture, whereas S. armatus formed only two types, armatus and armatus-longus types. All strains showed unicell-colony transformation. The cell became minimum when the daughter cell was released, and reached maximum at division.

• Bulletin of the Korean Chemical Society
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• 제22권9호
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• pp.948-952
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• 2001

Periodic mesoporous organosilicas with rope-based morphology from a reaction gel composition of 1 BTME : 0.57 ODTMABr : 2.36 NaOH : 353 H2O were synthesized. While long rope-shaped product dominated in case of static synthesis condition , gyroid type products instead of rope shaped product appeared and rope shaped product disappeared with agitation. PMO with such a long rope shaped morphology is firstly reported. Additionally, various rope-based morphologies depending on the degree of bending, twisting, folding and winding of rope such as spirals, discoids, toroids, and worm-like aggregates were observed. White powdered products were characterized by X-ray diffraction, N2 sorption measurement, SEM and TEM. From XRD pattern and TEM image, ODTMA-PMO with hexagonal symmetry was identified. The pore diameter and BET surface area of ODTMA-PMO are $32.9{\AA}$ and 799 m2g-1 , respectively. Hexagonally arrayed channels run with long axis of rope and rope-based shapes with various degree of curvature, which was elucidated by using TEM images.

• 한국미생물·생명공학회지
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• 제25권1호
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• pp.9-14
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• 1997

A bacterium, strain YK 391 producing extracellular cytosine deaminase, has been isolated from soil sample collected near Taegu City and identified. The strain YK 391 was observed to be a motile Gram-negative rod, and did not produced capsule nor spore. The bacterium produced acid from glucose and trehalose, not from arabinose. Esculine was nto hydrolyzed. The isolate could grow anaerobically at 37$\circ $C, but not at 4$\circ $C. Palmitoleic and palmitic acids comprised over 80% of the fatty acid composition of the strain. The strain. The strain YK 391 was identified as Chromobacterium violaceum YK 391 based on its morphological and physiolohical characteristics, and on the fatty acid composition. The extracellular cytosine deaminase produced by Chromobacterium violaceum YK 391 is believed to be unique because it was active not only on cytosine and 5-fluorocytosine but also on cytidine.

• Korea-Australia Rheology Journal
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• 제17권2호
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• pp.71-77
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• 2005

We investigated thermal, rheological, morphological and mechanical properties of a binary blend of poly(lactic acid) (PLA) and poly(butylene succinate adipate) (PBSA). The blends were extruded and their molded properties were examined. DSC thermograms of blends indicated that the thermal properties of PLA did not change noticeably with the amount of PBSA, but thermogravimetric analysis showed that thermal stability of the blends was lower than that of pure PLA and PBSA. Immiscibility was checked with thermal data. The rheological properties of the blends changed remarkably with composition. The tensile strength and modulus of blends decreased with PBSA content. Interestingly, however, the impact strength of PLA/PBSA (80/20) blend was seriously increased higher than the rule of mixture. Morphology of the blends showed a typical sea and island structure of immiscible blend. The effect of the blend composition on the biodegradation was also investigated. In the early stage of the degradation test, the highest rate was observed for the blend containing $80wt\%$ PBSA.

• 한국식품영양과학회지
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• 제19권6호
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• pp.636-640
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• 1990

For a studyon the production of ${\gamma}$-linolenic acid(GLA) by fungi 3 fungal strains were isolated from soil. Their cell growth lipid content and fatty acid composition were compared in shake flask culture. Among these fungi the fungus designated as FA-007 has high lipid content(21.1%) and GLA content(15.6% of total fatty acids) The fungal strain FA-007 was tentatively identified as Mucor sp. on the basis of morphological characteristics, Fungal oil produced by this fungus was composed of 75.2% neutral lipid 5.3% glycolipid and 19.5% phospholipid. Although the GLA content in phospholipid was higher than it in neutral lipid the GLA content in neurtal lipid was high as 15.5%.

• 미생물학회지
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• 제23권2호
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• pp.157-165
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• 1985

Bacterial identification was performed with morphological, physiological and biochemical tests to the isolates from the mudflat of 30cm depth sampled in Nakdong river estuary in March and June, 1985. Flavobacterium and Cnterobacteriaceae were regarded as dominants. Pseudomonas, Bacillus, Micrococcus, Vibrio, Aerococcus, Aerononas, Acinetobacter and Staphylococcus were founded in various depth. Vertical composition of bacterial genera in March was more diversiform than that of June. Character analysis was carried out with the calculation of similarity index (S). At a level of 85% similarity, the isolates were clustered into 5 groups and ungrouped 2 strains. Classifying groups of bacterial strains with determination schemes and groups from similarity index were in good agreement.