• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1139-1144
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• 2003

This paper addresses a theoretical study to calculate the amount of the stored energy due to vacancies during high-strain-rate deformation. The study concerns the role of excess vacancies, which can play an important role to increase the amount of stored energy. Molecular dynamics simulation using a 3D model is carried out and the result clearly shows that the excess vacancies are credited to generation of the stored energy.

• Journal of Mechanical Science and Technology
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• v.20 no.5
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• pp.621-633
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• 2006

To reflect the size effect of material $(1\sim15{\mu}m)$ during plastic deformation of polycrystalline copper, a constitutive equation which includes the strain gradient plasticity theory and intrinsic material length model is coupled with the finite element analysis and applied to plane strain deformation problem. The method of least square has been used to calculate the strain gradient at each element during deformation and the effect of distributed force on the strain gradient is investigated as well. It shows when material size is less than the intrinsic material length $(1.54{\mu}m)$, its deformation behavior is quite different compared with that computed from the conventional plasticity. The generation of strain gradient is greatly suppressed, but it appears again as the material size increases. Results also reveal that the strain gradient leads to deformation hardening. The distributed force plays a role to amplify the strain gradient distribution.

• Microbiology and Biotechnology Letters
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• v.41 no.1
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• pp.79-87
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• 2013

An unstable yet efficient phenanthrene-degrading bacterium strain Ph-3 was isolated from a petroleum-contaminated site at the Mathura Oil Refinery, India. The strain was identified as Pseudomonas sp. using a polyphasic approach. An analysis of the intermediates and assays of the degradative enzymes from a crude extract of phenanthrene-grown cells showed a novel and previously unreported pattern of 1, 2-dihydroxy naphthalene and salicylic acid production. While strain Ph-3 lost its phenanthrene- degrading potential during successive transfers on a rich medium, it maintained this trait in oligotrophic soil conditions under the stress of the pollutant and degraded phenanthrene efficiently in soil microcosms. Although the maintenance and in vitro study of unstable phenotypes are difficult and such strains are often missed during isolation, purification, and screening, these bacteria constitute a substantial fraction of the microbial community at contaminated sites and play an important role in pollutant degradation during biostimulation or monitored natural attenuation.

• Proceedings of the Korean Biophysical Society Conference
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• 2001.06a
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• pp.31-31
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• 2001

The native strain of serpins (serine protease inhibitors) has been recognized as a mechanism of biological regulation. Indeed, some stabilizing single residue mutations of human $\alpha$$_1$-antitrypsin, a prototype serpin, relieved local strain and caused the loss of inhibitory activity. The native strain of $\alpha$$_1$-antitrypsin is distributed throughout the whole molecule, but the strain that regulates the function directly is highly localized in the regions that appear to be mobilized during complex formation with a target protease.(omitted)

• Journal of Families and Better Life
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• v.17 no.4
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• pp.173-192
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• 1999

The differences of coping behaviors of professional and non-professional working mothers were assessed using data(n=704) from the working mothers with children under age 18. Professional working mothers' individual characters family and occupational conditions are more suitable than non-professionals for the coping behaviors. And such individual and situational aspects may relate to the differences of coping behaviors of he two groups. In general professional working mothers use coping behaviors more except the 'role reducation' and 'taking the support of fiends & neighbor' On the other hand the conservativeness and passive attitude in role strain coping is the same aspect of the two groups. Finally the relation of individual character family and occupational condition of working mothers to their coping behavios are slightly different in this two working mothers groups.

• Journal of Microbiology and Biotechnology
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• v.30 no.4
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• pp.497-504
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• 2020

For control of brucellosis in small ruminants, attenuated B. melitensis Rev1 is used but it can be virulent for animals and human. Based on these aspects, it is essential to identify potential immunogens to avoid these problems in prevention of brucellosis. The majority of OMPs in the Omp25/31 family have been studied because these proteins are relevant in maintaining the integrity of the outer membrane but their implication in the virulence of the different species of this genus is not clearly described. Therefore, in this work we studied the role of Omp31 on virulence by determining the residual virulence and detecting lesions in spleen and testis of mice inoculated with the B. melitensis LVM31 mutant strain. In addition, we evaluated the conferred protection in mice immunized with the mutant strain against the challenge with the B. melitensis Bm133 virulent strain. Our results showed that the mutation of omp31 caused a decrease in splenic colonization without generating apparent lesions or histopathological changes apparent in both organs in comparison with the control strains and that the mutant strain conferred similar protection as the B. melitensis Rev1 vaccine strain against the challenge with B. melitensis Bm133 virulent strain. These results allow us to conclude that Omp31 plays an important role on the virulence of B. melitensis in the murine model, and due to the attenuation shown by the strain, it could be considered a vaccine candidate for the prevention of goat brucellosis.

• Earthquakes and Structures
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• v.8 no.3
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• pp.541-553
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• 2015

Structural Health Monitoring (SHM) systems can provide valuable information regarding the safety of structures during and after ground motions which can be used by authorities to reduce post-earthquake hazards. Strain gages as a key element play an important role in the success of SHM systems. Reducing the number of required strain gages while keeping the efficiency of SHM system not only can reduce the cost of structural health monitoring but also avoids storage and process of uninformative data. In this study, a method based on performance based seismic design of structures is proposed for ideal placement of stain gages in structures. The robustness and efficiency of the proposed method is demonstrated through installation of strain gages on an Airport Traffic Control (ATC) Tower. The obtained results show that the number of required strain gages decrease significantly.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.483-486
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• 2005

In order to study the effect of strain states on the formation of shear textures during rolling in fcc metals, the evolution of textures was simulated by the full constrain model using various ideal strain states. Considering rolling as a two-dimensional problem, i.e., $\varepsilon_{22}\;=\;\varepsilon_{12}\;=\;\varepsilon_{23}\;=\;0$, the deviation from the plane-strain state manifest itself as nonzero contribution of $\varepsilon_{13}$. With increasing variations of $\varepsilon_{13}$, shear textures develop. The sign of ell hardly affects the evolution of textures. The texture simulation with various idealized strain states indicates that the ratio $\mid\varepsilon_{13}\mid/\mid\varepsilon_{11}\mid$ in each time interval in a roll gap plays a dominant role in the evolution of textures during rolling.

• Journal of Microbiology and Biotechnology
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• v.6 no.5
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• pp.315-320
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• 1996

The role of glyoxylate bypass in a lysine-producing Corynebacterium lactofermentum strain was analyzed. Unlike the wild type, the strain expressed enzymes of glyoxylate bypass during growth in the fermentation broth containing glucose as the carbon source. To evaluate the importance of glyoxylate bypass in the strain, we disrupted chromosomal aceA by using a cloned fragment of the gene. Site-specific disruption of aceA which codes for the isocitrate lyase, the first enzyme of the bypass, was confirmed by Southern blot analysis. The aceA mutant strain completely lost isocitrate lyase activity and ability to grow in a minimal medium containing acetate as the sole carbon source. The mutant strain was similar to its parental strain in growth characteristics and produced comparable amounts of lysine in shake flasks containing glucose as the carbon source. The amount of oxaloacetate accumulated in the fermentation medium was similar for both strains, suggesting that expression of glyoxylate bypass does not necessarily lead to the increase in intracellular oxaloacetate. These data clearly demonstrate that glyoxylate bypass does not function as one of the routes of carbon supply for lysine production in the strain. It appears that the leakiness of the glyoxylate bypass in the strain might be the result of a secondary mutation which arose during previous strain development by random mutagenesis.

• Smart Structures and Systems
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• v.14 no.4
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• pp.679-697
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• 2014

The strain data acquired from structural health monitoring (SHM) systems play an important role in the state monitoring and damage identification of bridges. Due to the environmental complexity of civil structures, a better understanding of the actual strain data will help filling the gap between theoretical/laboratorial results and practical application. In the study, the multi-scale features of strain response are first revealed after abundant investigations on the actual data from two typical long-span bridges. Results show that, strain types at the three typical temporal scales of $10^5$, $10^2$ and $10^0$ sec are caused by temperature change, trains and heavy trucks, and have their respective cut-off frequency in the order of $10^{-2}$, $10^{-1}$ and $10^0$ Hz. Multi-resolution analysis and wavelet shrinkage are applied for separating and extracting these strain types. During the above process, two methods for determining thresholds are introduced. The excellent ability of wavelet transform on simultaneously time-frequency analysis leads to an effective information extraction. After extraction, the strain data will be compressed at an attractive ratio. This research may contribute to a further understanding of actual strain data of long-span bridges; also, the proposed extracting methodology is applicable on actual SHM systems.