• 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.

• Molecules and Cells
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• v.20 no.3
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• pp.392-400
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• 2005

The genes encoding the DNA gyrase A (GyrA) and B subunits (GyrB) of Methylovorus sp. strain SS1 were cloned and sequenced. gyrA and gyrB coded for proteins of 846 and 799 amino acids with calculated molecular weights of 94,328 and 88,714, respectively, and complemented Escherichia coli gyrA and gyrB temperature sensitive (ts) mutants. To analyze the role of type II topoisomerases in the intrinsic quinolone resistance of methylotrophic bacteria, the sequences of the quinolone resistance-determining regions (QRDRs) in the A subunit of DNA gyrase and the C subunit (ParC) of topoisomerase IV (Topo IV) of Methylovorus sp. strain SS1, Methylobacterium extorquens AM1 NCIB 9133, Methylobacillus sp, strain SK1 DSM 8269, and Methylophilus methylotrophus NCIB 10515 were determined. The deduced amino acid sequences of the QRDRs of the ParCs in the four methylotrophic bacteria were identical to that of E. coli ParC. The sequences of the QRDR in GyrA were also identical to those in E. coli GyrA except for the amino acids at positions 83, 87, or 95. The $Ser^{83}$ to Thr substitution in Methylovorus sp. strain SS1, and the $Ser^{83}$ to Leu and $Asp^{87}$ to Asn substitutions in the three other methylotrophs, agreed well with the minimal inhibitory concentrations of quinolones in the four bacteria, suggesting that these residues play a role in the intrinsic susceptibility of methylotrophic bacteria to quinolones.

• Korean Circulation Journal
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• v.52 no.3
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• pp.218-219
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• 2022

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.05a
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• pp.409-412
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• 2004

Microstructures and mechanical properties of microalloyed cold forging steel and cold forged prototype automobile part are characterized. The work hardening according to the increase of plastic strain plays a major role in increasing the tensile strength of microalloyed cold forging steel during cold forming. On the other hand, inhomogeneous distribution of plastic strain causes variations in microstructure and mechanical properties. The relation between inhomogeneous distribution of plastic strain and variations in microstructure and mechanical properties is discussed. The variation of mechanical property in cold forged automobile part is analyzed using quantitative evaluation of plastic strain from finite element method.

• Proceedings of the KSR Conference
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• 2003.10c
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• pp.73-78
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• 2003

The residual stresses and. distortions of structures by welding exert negative effect on the safety of railroad structures. This investigation performs a thermal elasto-plastic analysis using finite element techniques to evaluate residual stresses in butted-welded joint. Considering this initial residual stresses, local stress and strain at the critical location (weld toe) during the loading were analyzed by elastic plastic finite element analysis. Fatigue crack initiation life and fatigue crack propagation life of butt-welded specimen were predicted by local strain approach and Neuber's role and Paris law. It is demonstrated that fatigue life estimates by local strain approach closely approximate the experimental results.

• Journal of Sensor Science and Technology
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• v.30 no.6
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• pp.420-428
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• 2021

In this study, linearized sweeping of a wavelength sweeping laser was realized. This technique was used to measure the strain on a fiber Bragg grating(FBG) sensor. For linear sweeping, PID control over the wavelength difference between linear and nonlinear sweeping was employed. The performance test showed that linear sweeping with a 46 nm range and a 1 kHz frequency held up well with a 99.5 % decrement in nonlinearity after the 120th feedback. When attached to a strain gage, the FBG sensor registered strain that matched the data sheet within a difference of 4.5[με]. Altogether, linear sweeping can play a leading role in monitoring a safety of large SOC structures as well as in other wavelength sweeping laser related fields.

• Korean Journal of Occupational Health Nursing
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• v.20 no.1
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• pp.55-64
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• 2011

Purpose: This study was to investigate the relationship between the level of emotional labor and occupational job stress of hospital nursing staff. Methods: The survey was conducted from Mar. to Oct. 2009 to collect data from clinical nurses (N=496). Results: The study showed that nurses without religion and those working in big-sized hospitals had higher scores in emotional labor, and those of 26~30 years old felt the highest stress in the occupational role. The same applied to the married, more work experienced, atheist and those working in big-sized hospitals. Unmarried, under educated nurses with less work experience working in the big-sized hospitals showed higher scores in personal strain. The scores of the personal resources depended on religion, work experience, marital status and position of their jobs. Emotional labor was positively correlated with an occupational role and personal strain, respectively, but the emotional labor, occupational role and personal strain were negatively correlated with personal resources respectively. Conclusion: Intervention program is required to reduce overload of nurse's role and to relieve physical and psychological strains of the under-30-age-group. Also, social support and rational/cognitive coping must be reinforced.

• Journal of Applied Biological Chemistry
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• v.56 no.3
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• pp.147-156
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• 2013

The objectives of this study were to investigate the effect of Lactobacillus paracasei subsp. tolerans JG22 isolated from pepper leaf jangajji on the mutagenic activity of N-methyl, N'-nitro, N-nitrosoguanidine (MNNG) and 2-nitrofluene (2-NF) and to evaluate the effect of physico-chemical pretreatment on the antimutagenic activity of the strain. The viable cells of JG22 strain displayed a significantly high (p <0.05) antimutagenic activity against both mutagens tested. The antimutagenic effect of JG22 strain seems to be positively correlated with the amounts of the cells in the incubation time. This strain produced the antimutagenic activity of the maximum levels after preincubation for 30 min. The binding of this strain against the mutagenic compounds might be mainly present in the cell wall fraction rather than the cytosol fraction. Pretreatment with proteolytic enzymes and simulated gastric and intestinal juices and at different pH values had no significant effect on two mutagens removal by the viable cells. However, the binding activity of the mutagen by the strain seems to be affected by heating, enzymes including $\alpha$-amylase and lysozyme, divalent ions, and sodium metaperiodate. Thus, carbohydrates consisting of the cell walls may be important elements responsible for the binding of MNNG and 2-NF by this strain. In conclusion, the binding of the mutagens to cells of JG 22 strain may play a vital role in suppressing the process of mutagenesis induced by mutagens.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.1078-1080
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• 2002

The pressure variation of interstitial fluid is one of the most important factors in bone physiology. In order to understand the role of interstitial fluid and the biomechanical interactions between fluid and solid constituents within bone, poroelastic theory was applied. The purpose of this study is to describe the behavior of calf vertebral trabecular bone composed of the porous solid trabeculae and the viscous bone marrow by using a commercial finite element analysis program based on the poroelasticity. In this study, the model was numerically tested for 5 different strain rates, i. e., 0.001, 0.01, 0.1, 1.0, and 10 per second. The material properties of the calf vertebral trabecular bone were utilized from the previous experimental study. Two asymptotic poroelastic response, the drained and undrained deformation, were predicted. From the predicted results for the simulated five strain rate, it was found that the pore pressure generation has a linearly increasing behavior when the strain rate is the highest at 10 per second, other wise it showed a nonlinear the strain rate Increased. Based on the results of the present study, it was suggested that the calf vertebral trabecular bone could be modeled as a porous material and its strain rate dependent material behavior could be predicted.

• Korean Journal of Family Social Work
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• no.54
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• pp.7-39
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• 2016

This study aimed at examining the effects of the environmental aspects of work-family role conflict on child-rearing attitudes of working mothers. To accomplish study purpose, 267 working mothers were asked to fill out the survey questionnaires. The research results were as follows. First with regards to the effects of both direction of work-family role conflict on child-rearing attitudes of working mothers: the work interference with family conflict was negatively related to affectionate child-rearing attitudes of working mothers; the work interference with family conflict was positively related to rejection child-rearing attitudes and control child-rearing attitudes of working mothers; and the family interference with work conflict was negatively related to autonomic child-rearing attitudes of working mothers. Second, in terms of the effects of the three types of work-family role conflict on child-rearing attitudes of working mothers: the work family strain-based conflict was negatively related to affectionate child-rearing attitudes of working mothers; the work family strain-based conflict was positively related to rejection child-rearing attitudes and control child-rearing attitudes of working mothers; and the family work strain-based conflict was negatively related to affectionate child-rearing attitudes and autonomic child-rearing attitudes of working mothers. Based on these results, suggestions and implications were provided.