• Archives of Metallurgy and Materials
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• 제64권3호
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• pp.863-867
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• 2019

The effects of carbon content on the austenite stability and strain-induced transformation of nanocrystalline Fe-11% Ni alloys were investigated using X-ray analysis and mechanical tests. The nanocrystalline FeNiC alloy samples were rapidly fabricated using spark plasma sintering because of the extremely short densification time, which not only helped attain the theoretical density value but also prevented grain growth. The increased austenite stability resulted from nanosized crystallites in the sintered alloys. Increasing compressive deformation increased the volume fraction of strain-induced martensite from austenite decomposition. The kinetics of the strain-induced martensite formation were evaluated using an empirical equation considering the austenite stability factor. As the carbon content increased, the austenite stability was enhanced, contributing to not only a higher volume fraction of austenite after sintering, but also to the suppression of its strain-induced martensite transformation.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2009년 추계학술발표대회
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• pp.202-204
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• 2009

Erosion is a common failure mode of materials frequently encountered in plant and power industry. Although the erosion resistance of Fe-base alloy has been inferior to the other expensive materials, it is expected that the strain-induced martensitic transformation can impart high erosion resistance to Fe-base alloy. The key technology to develop Fe-base metal cored welding wire for erosion resistant overlay welding may include the strain-induced metallurgy for hardening rate control and the welding flux metallurgy for dilution control. Sophisticated studies showed that the strain-induced martensitic transformation behavior was related to the critical strain energy which was dependent on the alloy composition. Dilution and bead shape of overlay weld were proved to be affected by metal transfer mode during gas tungsten arc welding and elements in welding fluxes. It was considered that the highly erosion resistant Fe-base overlay weld could be achieved by precise control of alloy composition to have proper level of critical strain energy for energy absorption and welding flux formulation to have small amount of deoxidizing metallic elements for dilution.

• 미생물학회지
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• 제18권2호
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• pp.51-58
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• 1980

Mutational experiments were performed to improved to improve the protease productivity of Aspergillus flavus KU 153, which is selected among the wild strains. A UV-induced mutant strain having high protease productivity was obtained by the use of the clear zone method as a simple criterion for a primary screening test. Neutral and alkaline protease activities of hte mutant strain were higher than 1.8 times, comopared with those of the parental strain, respectively, while in the case of acid protease, it was 2.7 times. The mutant strain selected was more powerful in the production of cellulase and amylase, as well s protease in wheat bran, compared with those of the parental strain. protease production of the parental strain has reached maximum level at 3 days culture, while alkaline nad neutral protease production of the mutantstrain has reached at 2 days culture. On the other hand, the mutant strain formed the spore slowly, compared with the parental strain. Column chromatography of the neutral protease on DEAE-Sephadex A-50 showed that the mutant strain was not induced the formation of another neutral protease isozyme, but induced the variation in the function of regulatory gene.

• Structural Engineering and Mechanics
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• 제54권2호
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• pp.199-219
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• 2015

This paper presents the non-destructive evaluation of a high-speed railway bridge using train-induced strain responses. Based on the train-track-bridge interaction analysis, the strain responses of a high-speed railway bridge under moving trains with different operation status could be calculated. The train induced strain responses could be divided into two parts: the force vibration stage and the free vibration stage. The strain-displacement relationship is analysed and used for deriving critical displacements from theoretical stain measurements at a forced vibration stage. The derived displacements would be suitable for the condition assessment of the bridge through design specifications defined indexes and would show certain limits to the practical application. Thus, the damage identification of high-speed railways, such as the stiffness degradation location, needs to be done by comparing the measured strain response under moving trains in different states because the vehicle types of high-speed railway are relatively clear and definite. The monitored strain responses at the free vibration stage, after trains pass through the bridge, would be used for identifying the strain modes. The relationship between and the degradation degree and the strain mode shapes shows certain rules for the widely used simply supported beam bridges. The numerical simulation proves simple and effective for the proposed method to locate and quantify the stiffness degradation.

• 펄프종이기술
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• 제31권3호
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• pp.105-109
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• 1999

The purpose of this experiment was to see the effect of local basis weight on the local strain during changing moisture content in handsheets. The averaged strain value of the whole size of paper sheet did not give more valuable information to explain non uniform deformation in the paper sheet. The combination of intact strain measurement system KISA (Linear Image Strain Analysis) and local basis weight measurement method using a scanner made it possible to compare local basis weight with local strain to explain moisture induced paper deformation . Usually higher basis weight local area showed higher moisture induced local strain. However, the hygro-induced strain values were highly affected by the behavior of neighbor local areas. Well distributed local basis weight paper would give more uniform local strains than those of non-uniformed local basis weight paper.

• Smart Structures and Systems
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• 제33권3호
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• pp.189-199
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• 2024

To properly extract the strain components under varying operational conditions is very important in bridge health monitoring. The abnormal sensor readings can be correctly identified and the expected operational performance of the bridge can be better understood if each strain components can be accurately quantified. In this study, strain components under varying load conditions, i.e., temperature variation and live-load variation are evaluated based on field strain measurements collected from a real concrete box-girder bridge. Temperature-induced strain is mainly regarded as the trend variation along with the ambient temperature, thus a smoothing technique based on the wavelet packet decomposition method is proposed to estimate the temperature-induced strain. However, how to effectively extract the vehicle-induced strain is always troublesome because conventional threshold setting-based methods cease to function: if the threshold is set too large, the minor response will be ignored, and if too small, noise will be introduced. Therefore, an autoencoder framework is proposed to evaluate the vehicle-induced strain. After the elimination of temperature and vehicle-induced strain, the left of which, defined as the model error, is used to assess the operational performance of the bridge. As empirical techniques fail to detect the degraded state of the structure, a clustering technique based on Gaussian Mixture Model is employed to identify the damage occurrence and the validity is verified in a simulation study.

• Food Science and Biotechnology
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• 제17권6호
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• pp.1207-1213
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• 2008

The possible protective effects of highly zinc-containing yeast Saccharomyces cerevisiae, FF-10 strain, isolated from tropical fruit rambutan on acute alcoholic liver injury in rats were evaluated. Zinc concentration in this strain was 30.6mg%. The activities of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and $\gamma$-glutamyl transpeptidase ($\gamma$-GTP) were highly increased when alcohol was treated, relative to the normal rats. Also, a highly significant increase in the blood alcohol and acetaldehyde levels by alcohol treatment was observed. Administration of FF-10 strain markedly prevented alcohol-induced elevation of the activities of serum ALT, AST, and $\gamma$-GTP, and the levels of blood alcohol and acetaldehyde, and these reduced levels reached to that of normal rats. As compared with alcohol treated control rats, the FF-10 strain supplementation showed highly decreased the triglyceride concentration in serum. Alcohol treatment induced the marked accumulation of small lipid droplets, hepatocytes necrosis, and inflammation, but FF-10 strain administration attenuated to alcohol-induced accumulation of small lipid droplets and hepatocyte necrosis in the liver. Therefore, the current finding suggests that zinc-enriched yeast FF-10 strain isolated from tropical fruit rambutan may have protective effect against alcohol-induced hepatotoxicity.

• 한국결정학회지
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• 제12권1호
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• pp.14-19
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• 2001

Effects of electric-field-induced lattice distortion on the polarization and strain were investigated in Pb(Mg/sub 1/3/Nb/sub 2/3)O₃ relaxor ferroelectric ceramics in the temperature range of -50℃∼90℃. The ratio of residual strain and polarization (S/sub r//P/sub r/ rarely depends on the temperature. However, the ratio of the electric field included strain and polarization (S/sub induced//P/sub induced/) increased as the temperature decreases below phase transition temperature. To explain these experimental results, a simple rigid ion model concentrating on only Bo/sub 6/ octahedron was suggested.

• 한국식품영양과학회지
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• 제26권3호
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• pp.528-533
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• 1997

This study was undertaken to determine the antimutagenic effects of Synurus deltoides extracts on the mutagenesis induced by 3-amino-1, 4-dimethyl-5-H-pyrido[4, 3-blindol(Trp-P-1), 2-amitnofluorene (2-AF) and 4-nitroquinolin-1-oxide(4NQO) using Ames test. Raw juice, heated juice, and ethanol extract from Synurus deltoides itself did not induce mutagenesis. The raw juice, heated juice and ethanol extract of 50${mu}ell$/plate showed approximately 90%, 37% and 28% inhibitory effect on the mutagenesis induced by Trp-P-1 against TA98 strain, while 80%, 60% and 58% inhibition was observed on the mutagenesis induced by 2-AF at the concentration of 200${mu}ell$/plate, respectively. TA100 strain was more sensitive than TA98 strain by raw juice, heated juice and ethanol extract on the mutagenesis induced by Trp-P-1 and 2-AF. Meanwhile, the raw juice, heated juice, and ethanol extract showed very limited inhibitory effects on the mutagenesis induced by 4-NQO against TA98 and TA100 strain. These results indicate that raw juice had the strongest inhibitory effect on the Trp-P-1 or 2-AF induced mutagenesis, but all of the extracts had a little antimutagenc effects on the 4-NQO induced mutagenesis.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 가을 학술발표회 논문집
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• pp.209-216
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• 2000

When subjected to earthquake shaking, saturated sandy soil may generate excess pore pressure. And a time may come when initial confining pressure will equal to excess pore pressure. Depending on the characteristics of the soil and the length of the drainage path, excess pore pressure was dissipated after earthquake. For this reason, it was induced settlement in grounds and fatal damage of various structures. In this study, settlement in silty sand grounds induced earthquake was evaluated using post-liquefaction constitutive equation between volumetric strain and shear strain from previous study. Using that, it was proposed that simplified estimation of settlement in silty sand grounds induced liquefaction.