• Smart Structures and Systems
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• v.31 no.6
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• pp.585-599
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• 2023

Field monitoring techniques offer an attractive approach for understanding bridge behavior under in-service loads. However, the investigations on bridge behavior under high-speed train load using field monitoring data are limited. The focus of this study is to explore the structural behavior of an in-service long-span steel truss arch bridge based on field monitoring data. First, the natural frequencies of the structure, as well as the train driving frequencies, are extracted. Then, the train-induced bearing displacement and structural strain are explored to identify the effects of train loads and bearings. Subsequently, a sensitivity analysis is performed for the impact factor of strain responses with respect to the train speed, train weight, and temperature to identify the fundamental issues affecting these responses. Additionally, a similar sensitivity analysis is conducted for the peak acceleration. The results indicate that the friction force in bearings provides residual deformations when two consecutive trains are in opposite directions. In addition, the impact factor and peak acceleration are primarily affected by train speed, particularly near train speeds that result in the resonance of the bridge response. The results can provide additional insight into the behavior of the long-span steel truss bridges under in-service high-speed train loads.

• Research in Plant Disease
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• v.30 no.1
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• pp.95-98
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• 2024

In a survey conducted in March 2023, Euphorbia hypogaea plants cultivated within greenhouses in Yongin, Korea exhibited water-soaked areas near the stem base, close to the soil. Subsequent isolation from diseased E. hypogaea led to the identification of a bacterial strain, designated as CBNUMPBL-103. The isolate was identified as Dickeya dadantii through sequencing of the 16s rRNA and phylogenetic analysis. The pathogenicity of the isolate was confirmed by inoculating it into healthy E. hypogaea, resulting in the manifestation of similar symptoms observed during the survey. The re-isolated strain recovered from inoculated plants showed a similar morphology with the inoculated strain. This is the first documentation of D. dadantii causing soft rot of E. hypogaea in Korea.

• Journal of Microbiology
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• v.44 no.6
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• pp.617-621
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• 2006

Coprinellus congregatus secreted a laccase isozyme when the culture was transferred to an acidic liquid medium (pH 4.1). The laccase cDNA gene (clac2) was used as a probe for cloning of the genomic laccase gene (lac2) including the promoter (Plac2). The open reading frame (ORF) of lac2 had 526 deduced amino acids and four conserved copper binding domains as other fungal laccases. Recombinant plasmid (pRSlac2p-cDNA) of lac2 cDNA with its own promoter was transformed in Saccharomyces cerevisiae. Expression of the transformed lac2 gene was induced by oxidative stress ($H_2O_2$) in yeast and the survival rate of the transformed yeast strain was greatly increased when compared with that of the control strain transformed with pRS316 yeast vector.

• The Plant Pathology Journal
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• v.22 no.3
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• pp.278-282
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• 2006

Bacillus vallismortis EXTN-1, a biocontrol agent in cucumber, tomato and potato was tested in rice pathosystem against rice fungal pathogens viz. Magnaporthe grisea, Rhizoctonia solani and Cochliobolus miyabeanus. Apart from increasing the yield in the bacterized plants (11.6-12.6% over control), the study showed that EXTN1 is effective in bringing about disease suppression against all the tested fungal pathogens. EXTN-l treatment resulted in 52.11% reduction in rice blast, 83.02% reduction in sheath blight and 11.54% decrease in brown spot symptoms. As the strain is proven as an inducer for systemic resistance based on PR gene expression in Arabidopsis and tobacco models, it is supposed that a similar mechanism works in rice, bringing about disease suppression. The strain could be used as a potent biocontrol and growth-promoting agent in rice cropping system.

• The Plant Pathology Journal
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• v.15 no.4
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• pp.247-250
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• 1999

Wasabies showing mosaic symptoms were collected and extracted for virus purification. Tobacco mosaic virus (TMV) was identified as causal agent by electron microscopy and nucleic acid and coat protein analyses. TMV strains were determined by enzyme-linked immunosorbent assay (ELISA). TMV was identified as W and C strain in wasabi. The results of host reaction indicated that this virus induced local lesions on Nicotiana tabacum cv. Bright Yellow and N. glutinosa, leaf spots on Chenopodium amaranticolor and mosaic symptoms on wasabi. Rot shape virus particles were observed and was about 300 nm in length. About 6.5 kb single RNA molecule was observed from extracted viral RNA sample and 26 KDa coat protein was detected in denatured acrylamide gel. Infection ratio of TMV was 8% for the first cultivation year, but was 22% for the second year when TMV-W antiserum was used. The results of this experiment showed that infection ratios of both TMV-W and TMV-C strains were higher compared to that of TMV-P strain.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.561-568
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• 2003

The protection of adjacent structures in urban excavation has been an important issue. But the research on the interaction between ground movements and adjacent structure has been scarce, therefore this study was necessitated. Current design practice for the prediction of excavation-induced ground movements heavily rely on empirical method. In this study, damage levels of brick building are examined closely by means of angular distortion, deflection ratio, horizontal strain. The results of numerical analysis indicated that the movement of actual building was 60∼65% of the ground movement, while angular distortion was 45∼65%. Also numerical analysis for the assessment of brick building can be applied to the building protection at various construction stages.

• Structural Engineering and Mechanics
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• v.16 no.5
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• pp.581-595
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• 2003

Since the conventional direct approaches are hard to be applied for damage diagnosis of complex large-scale structures, a two-step approach for diagnosing the joint damage of framed structures is presented in this paper by using artificial neural networks. The first step is to judge the damaged areas of a structure, which is divided into several sub-areas, using probabilistic neural networks with natural Frequencies Shift Ratio inputs. The next step is to diagnose the exact damage locations and extents by using the Radial Basis Function (RBF) neural network with the second Element End Strain Mode of the damaged sub-area input. The results of numerical simulation show that the proposed approach could diagnose the joint damage of framed structures induced by earthquake action effectively and has reliable anti-jamming abilities.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.5
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• pp.15-24
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• 1997

We propose a tunable add/drop filter in a form of an all-fiber mach-zehnder interferometer iwth one bragg grating at each arm. This device can be tuned by inducing a strain in the bragg grating. We also theoretically analyze the outut characteristics of the tunable add/drop filter. As a result of simulation, we know that the proposed tunable add/drop filter works well. When 2*10$^{-3}$ of strain is induced, the reflected spectrum shifts about 3nm. And its reflected spectral width is about 0.3nm. In this case roughly 5 channels can be tuned, assuming the channel spacing is 0.3nm. When the pathlengths of the both arms are not the same, the transmissivities at the add and output ports and the reflectivity at the tap port varies sinusoidally with the pthlength difference. To maintain the transmissivities above 90% in the wavelength tuning range of 20nm the pathlength difference less than 16.mu.m is required.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.478-481
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• 2004

This study presents the combined effect of electric Held application and mechanical compressive stress loading on deformation in a multilayer ceramic actuator, designed with stacking alternatively 0.2(PbMn$\_$1/3/Nb$\_$2/3/O$_3$)-0.8(PbZr$\_$0.475/Ti$\_$0.525/O$_3$) ceramics and Ag-Pd electrode. The deformation behaviors were thought to be attributed to relative 180$^{\circ}$domain quantities which is determined by pre-loaded stress and electric field. The non-linearity of piezoelectricity and strain are dependent upon the young's modulus resulting from the domain reorientation.

• Journal of Microbiology
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• v.40 no.1
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• pp.86-89
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• 2002

Rhodococcus sp. strain T104, which is able to grow on either biphenyl or limonene, was found to utilize phenol as sole carbon and energy sources. Furthermore, T104 was positively identified to possess three separate pathways for the degradation of limonene, phenol, and biphenyl. The fact that biphenyl and limonene induced almost the same amount of catechol 1,2-dioxygenase activity indicates that limonene can induce both upper and lower pathways for biphenyl degradation by T104.