• Nuclear Engineering and Technology
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• 제38권7호
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• pp.619-638
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• 2006

Low temperature irradiation can significantly harden metallic materials and often lead to strain localization and ductility loss in deformation. This paper provides a review on the radiation effects on the deformation of metallic materials, focusing on microscopic and macroscopic strain localization phenomena. The types of microscopic strain localization often observed in irradiated materials are dislocation channeling and deformation twinning, in which dislocation glides are evenly distributed and well confined in the narrow bands, usually a fraction of a micron wide. Dislocation channeling is a common strain localization mechanism observed virtually in all irradiated metallic materials with ductility, while deformation twinning is an alternative localization mechanism occurring only in low stacking fault energy(SFE) materials. In some high stacking fault energy materials where cross slip is easy, curved and widening channels can be formed depending on dose and stress state. Irradiation also prompts macroscopic strain localization (or plastic instability). It is shown that the plastic instability stress and true fracture stress are nearly independent of irradiation dose if there is no radiation-induced phase change or embrittlement. A newly proposed plastic Instability criterion is that the metals after irradiation show necking at yield when the yield stress exceeds the dose-independent plastic instability stress. There is no evident relationship between the microscopic and macroscopic strain localizations; which is explained by the long-range back-stress hardening. It is proposed that the microscopic strain localization is a generalized phenomenon occurring at high stress.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.141.1-141
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• 2003

Forty six isolates of bean common mosaic virus (BCMV) collected from azuki bean, mungbean, kidney bean, cowpea, broad bean and peanut were classified into three groups based on biological, serological, cytopathological, and molecular characteristics. Group I induced vein-banding symptoms in cowpea which was similar to those produced by the BCMV-cowpea strain. Group II caused mosaic symptoms in azuki bean but not in peanut and tobacco. Since this character was different from that of previously described BCMV strain, group II may not belong to BCMV GroupIII induced vein-clearing symptoms in azuki bean, kidney bean and peanut, which are typical symptoms for BCMV-peanut stripe virus strain. Virus inclusion patterns of BCMV groups were similar to those of Potyvirus subdivision III with the scroll, pinwheel and long laminated inclusions. However, the inclusions of laminated aggregates were never observed in mungbean isolates. Multiple alignment as well as cluster dendrograms of 3'noncoding region (3'-NCR) and a part of coat protein gene (CP) suggested that group I belongs to the BCMV-cowpea strain, group II to the BCMV-azuki bean strain, and group III to the BCMV-peanut stripe virus strain. Since molecular phylogenesis of BCMV based on nucleotides of 3'-NCR and coat protein differed from the grouping based on virulence differentiation, and BCMV groups are more closely related to each other with the same host origin, other characteristics of those strains are under investigation.

• Bulletin of the Korean Chemical Society
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• 제10권4호
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• pp.404-406
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• 1989

• 한국전기전자재료학회논문지
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• 제24권7호
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• pp.599-604
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• 2011

A highly strained nanostructure comprising crystallographically aligned HgTe nanoinclusions and a surrounding PbTe matrix has been synthesized using a precipitation process of supersaturated HgTe-PbTe alloys. From the early precipitation stage, HgTe nanoinclusions take disk shape, which is transformed from initial HgTe nuclei, although there is no lattice constant difference of the two end components at standard state. As a primary reason for the morphological transformation of the initial spherical HgTe nuclei to HgTe nanodisks, the induced lattice mismatch is suggested. On the condition that the HgTe nanodisks maintain perfect coherent nature with PbTe matrix, the stress-free lattice constant of constrained HgTe nanodisks has been calculated based on the defined concept of the strain-induced tetragonality, the linear elasticity and the actual measurement in HRTEM images.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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• pp.211-213
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• 2014

Simultaneous measurements of planar laser-induced fluorescence (PLIF) of OH radicals and particle image velocimetry (PIV) were used to investigate the strain rates and OH structure characteristics of turbulent syngas non-premixed jet flames close to blowoff. Mean values of the maximum principal strain rate on OH layer decreases with the axial distance, and its standard deviation is significantly large upstream. Strain rate on stabilization region of the stable flame is only about a half of that of the flame near blowoff.

• Structural Engineering and Mechanics
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• 제46권2호
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• pp.231-244
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• 2013

An efficient method is proposed here to identify multiple damage cases in structural systems using the concepts of flexibility matrix and strain energy of a structure. The flexibility matrix of the structure is accurately estimated from the first few mode shapes and natural frequencies. Then, the change of strain energy of a structural element, due to damage, evaluated by the columnar coefficients of the flexibility matrix is used to construct a damage indicator. This new indicator is named here as flexibility strain energy based index (FSEBI). In order to assess the performance of the proposed method for structural damage detection, two benchmark structures having a number of damage scenarios are considered. Numerical results demonstrate that the method can accurately locate the structural damage induced. It is also revealed that the magnitudes of the FSEBI depend on the damage severity.

• 약학회지
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• 제30권6호
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• pp.317-322
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• 1986

To clarify resistance mechanisms of lincosamide antibiotics, it was examined whether lincosamide antibiotics was able to induce high resistance to macrolide and lincosamide antibiotics against EMR-1 strain of Bacillus species. And it was also examined whether the inducible resistance was plasmid-mediated or chromosome-mediated. This strain was identified as Bacillus licheniformis by its morphological and physiological characteristics. The subinhibitory concentrations of lincomycin and clindamycin induced high resistance in the strain to lincosamide antibiotics, but not to macrolide antibiotics. The inducible resistance was not eliminated by treating the strain with ethidium bromide, and plasmid was not identified by the alkaline lysis method of plasmid preparation. These results indicate, therefore, that the inducible resistance to macrolide and lincosamide antibiotics in the strain may be chromosome-mediated, not plasmid-mediated.

• 한국철도학회논문집
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• 제7권2호
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• pp.85-92
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• 2004

This paper consists of two parts. One is finite element analysis of the redistribution of residual stresses of weld specimen by cutting. This work is necessary to predict the actual residual stress distribution of weld specimens used in fatigue test. The other subject is to calculate the relaxation of residual stress and the strain field induced by cyclic loading. To obtain fatigue life of weldment, the value of strain amplitude at each position is necessary, for example in the strain-life approach, and the numerical results can be used to verify experimental strain measurements. Thermo mechanical finite element analyses were conducted on the commercial package ABAQUS.

• 한국소음진동공학회논문집
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• 제19권9호
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• pp.915-921
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• 2009

Cellulose based electro-active paper(EAPap) is considered as a new smart material which has a potential to be used for biomimetic actuators and sensors. Beside of the natural abundance, cellulose EAPap is fascinating with its biodegradability, lightweight, high mechanical strength and low actuation voltage. When the external stress is applied to EAPap, it can generate the electrical output due to its piezoelectric property. Using piezoelectric behavior of EAPap, we studied the feasibility of EAPap as mechanical strain sensor applications and compared to commercial strain sensor. By measuring the induced output voltage from the thin piezoelectric cellulose EAPap under static and dynamic force, we propose cellulose EAPap film as a potential strain sensor material.

• IMMUNE NETWORK
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• 제15권1호
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• pp.27-36
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• 2015

In the present study, we investigated the protection conferred by a live attenuated Salmonella enterica serovar Typhimurium (ST) strain against Salmonella Typhimurium, Salmonella Gallinarum (SG), and Salmonella Enteritidis (SE) infection in layer chickens. Birds were orally primed with the attenuated ST strain at 7 days of age and then boosted at 4 weeks post prime immunization (PPI). Sequential monitoring of plasma IgG and mucosal secretory IgA (sIgA) levels revealed that inoculation with ST induced a significant antibody response to antigens against ST, SE, and SG. Moreover, significant lymphoproliferative responses to the 3 Salmonella serovars were observed in the immunized group. We also investigated protection against virulent ST, SE, and SG strain challenge. Upon virulent SG challenge, the immunized group showed significantly reduced mortality compared to the non-immunized group. The reduced persistence of the virulent ST and SE challenge strains in the liver, spleen, and cecal tissues of the immunized group suggests that immunization with the attenuated ST strain may not only protect against ST infection but can also confer cross protection against SE and SG infection.