• Korean Journal of Microbiology
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• v.29 no.2
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• pp.143-147
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• 1991

The root nodules and Glycine max were classified as determinate nodule based on their morphological characteristics, and isolated endosymbiont as a Bradyrhizobium based on its growth rate and single subpolar flagellum. The isolate was similar to B. japonicum USDA110 in utilization of carbon source, growth at 38.deg.C and 2% NaCl, production of $H_{2}$S and especially in the restriction endonuclease digestion pattern of symbiotic genes, allowing them to be placed in sTI group together. The former, however, grew better than the later in broad pH range from 5.0 to 9.5. Infectivity and effectivity of the isolate were confirmed by inoculation of soybean seedlings with the isolates. Characteristics of the reisolated endosymbiont from induced root nodules were identical to those of the first isolate. From these results, it was confirmed that Bradyrhizobium strain isolated from the root nodules of Glycine max was a real symbiont, and was named B. japonicum SNU001.

• Microbiology and Biotechnology Letters
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• v.23 no.1
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• pp.68-74
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• 1995

A bacterial strain A-6 producing the high level of an extracellular inulin fructotransfe rase(depolymerizing)(EC 2.4.1.93) which converts inulin into di-D-fructofuranose dianhydride III (DFAIII) was isolated from soil. The isolated strain could be classified as a species belonging to the genus Arthrobacter based on its morphological and physiological characteristics identified in this work. Production of the enzyme was induced by inulin, and the highest activity was detected in the slightly acidic medium supplemented with 2.5% inulin and 0.1% trypton as a sole carbon and a nitrogen source, respectively. Under the optimal conditions, the enzyme activity in the culture supernatant reached approximately 60 uints/ml after 96 hours of cultivation. The optimum pH and temperature for the crude enzyme preparation from Arthrobacter sp. A-6 were pH 5.0 and 60$\circ$C , respectively. The DFA produced by the action of the inulin fructotransferase was confirmed to be DFAIII by paper chromatography, HPLC and $^{13}$C-NMR spectroscopy.

• Structural Engineering and Mechanics
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• v.23 no.4
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• pp.339-352
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• 2006

Observing the unique stress-strain curves of the superelastic shape memory alloy (SMA) in tension and compression, the primary intention of this study is to investigate the behavior of the shafts made of the same material, under torsional loading-unloading cycles for large angle of twist. Experiments have been performed for the superelastic SMA shafts with different unsupported lengths and angles of twist and the results are compared with those of stainless steel (SUS304) shafts under similar test conditions. As expected for the superelastic SMA, the residual strains are small enough after each cycle and consequently, the hysteresis under loading-reverse loading is much narrower than that for the SUS304. For large angle of twists, the torsional strength of the superelastic SMA increases nonlinearly and exceeds that of SUS304. Most interestingly, the slender solid superelastic SMA shafts are found to buckle when acted upon torsion for large angle of twist.

• Journal of The Korean Society of Agricultural Engineers
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• v.50 no.2
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• pp.45-52
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• 2008

Contaminant transport has been widely studied in rigid porous media, but there are some cases where a large volumetric stain occurs such as dewatering of dredged contaminated sediment, landfill liner, and in-situ capping. This paper presents a numerical investigation of contaminant transport coupled with large strain consolidation. Consolidation test was performed with contaminated sediments collected in Gary, Indiana, U.S. to obtain constitutive relationships, which are required for numerical simulations. Numerical results using CST2 show an excellent agreement with measured settlement and excess pore pressure. CST2 is then used to simulate contaminant transport during and after in-situ capping. Numerical simulations provide that transient advective flows caused by consolidation significantly increase the contaminant transport rate. In addition, the numerical simulations revealed that active capping with Reactive Core Mat (RCM) significantly decelerates consolidation-induced contaminant transport.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.251-254
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• 2003

In recent years, shearogrpahy has significantly improved capabilities In the areas of unbend and separation detection in tires. Although shearography has many advantages fur qualitative evaluation, the technique remains the problem of quantitative analysis of inside defects, because shearography needs several effective factors including the amount of shearing, shearine direction and induced load, which exist as barrier for the quantitative analysis of inside defects. Since the factors are highly dependent on inspectors skill and also affect the in-situ workability. The factors were optimized and the size of cracks inside of pipeline and tire has been quantitatively determined.

• Proceedings of the Korean Society of Veterinary Pathology Conference
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• 2003.10a
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• pp.6-6
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• 2003

Listeria monocytogenes is a facultative bacterium that cause severe clinical disease including meningoencephalitis, septicaemia, and abortion in pregnant women, newborn infants, the debilitated elderly or immunocompromised people. In preliminary experiments on murine listeriosis we noticed suppurative gastritis in mice infected with L. monocytogenes by the intragastric route. The aims of the present study were ⅰ) to describe the histopathology of the experimentally listeria-induced gastroenteritis ⅱ) to investigate the influence of bacterial strain and laboratory mouse strain on infectivity and on the severity of the infection; [3] to examine possible effects of preliminary intragastric administration of sodium bicarbonate. (omitted)

• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.3
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• pp.105-113
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• 1997

We constructed a very accurate fiber bragg grating sensor system using an unbalanced mach-zehnder interferometer which converts the measurand-induced bragg wavelength shift to phase change of th einterference signal. With a shielded reference grating, output phase drift which orginates from the thermal drift on the interferometer was compensated. Mesured accuracy of the constructed system was 0.03 .deg. C and 0.26.mu. strain for temperature and strain measuremtn, respectively. It is over 300 times better resolution compared to the conventional optical spectrum analyzer which has 0.1nm wavelength resolution capability.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2000.02a
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• pp.6-8
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• 2000

The critical current density, Jc, of superconductor tape significantly depends on microstructural evolution during mechanical deformation. In this study, we fabricated Bi-2223 superconductor tape by PIT technique, and investigated mechanical properties of mono- and 61-filamentary tapes and their joined tapes. The strength of mono-filament tape was higher than those of 61-filament tape was higher than those of 61-filament tape, respectively. On the other hand, elongation of mono-filament tape, respectively. On the other hand, elongation of mono-filament tape was lower than 61 filament tape. The joined tapes shows lower strength and irreversible strain than those of unjoined tapes. The reduced strength and irreversible strain for joined tape is probably related to the induced damages such as irregular interface and Ag-instrusion in the transition region which acts as a stress concentration.

• Structural Engineering and Mechanics
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• v.75 no.1
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• pp.101-108
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• 2020

The present study intends to analyze damage in thin-walled steel cylinders undergoing constant internal pressure and thermal cycles through use of anisotropic continuum damage mechanics (CDM) model coupled with nonlinear kinematic hardening rule of Chaboche. Materials damage in each direction was defined based on plastic strain and its direction. Stress and strain distribution over wall-thickness was described based on the CDM model and the return mapping algorithm was employed based on the consistency condition. Plastic zone expansion across the wall thickness of cylinders was noticeably affected with change in internal pressure and temperature gradients. Expansion of plastic zone over wall-thickness at inner and outer surfaces and their boundaries demarking elastic and plastic regions was attributed to the magnitude of damage induced over thermomechanical cycles on the thin-walled samples tested at various pressure stresses.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.6 no.3
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• pp.26-35
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• 1997

In this study, the drawing characteristics of circular drawbead are examined with the plane strain elastic-plastic FE Method. Both the clamping load and the drawing load investigated by varying the process variables such as drawbead radius, closing depth and friction condition. The effective strain induced by the draw bead is also investigated. In order to verify the results, the computed results are compared with the existing experimental results. It has been found that both the clamping load and drawing loads are related with the geometry of the bead rather than the lubrication conditions.