• Structural Engineering and Mechanics
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• v.16 no.4
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• pp.405-422
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• 2003

Scaled brick masonry panels were tested under cyclic unialxial compression loading to evaluate its deformation characteristics. An envelope stress - strain curves, a common point curves and stability point curves were obtained for various cyclic test conditions. Loops of the stress-strain hysteresis were used to determine the energy dissipation for each cycle. Empirical expressions were proposed for the relations between energy dissipation and envelope and residual strains. These relations indicated that the decay of masonry strength starts at about two-third of peak stress.

• Structural Engineering and Mechanics
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• v.11 no.5
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• pp.565-574
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• 2001

Experimental investigation into the behaviour of half-scale brick masonry panels were conducted under cyclic loading normal to the bed joint and parallel to the bed joint. For each cycle, full reloading was performed with the cycle peaks coinciding approximately with the envelope curve. Unloading, however, was carried out fully to zero stress level and partially to two different stress levels of 25 percent and 50 percent of peak stress. Stability point limit exhibits a unique stress-strain curve for full unloading but it could not be established for partial unloading. Common point limit was established for all unloading-reloading patterns considered, but its location depends on the stress level at which unloading is carried to. Common point curves were found to follow an exponential formula, while residual strains versus envelope strains can be expressed by a polynomial function of a single term. The relation between residual strain and envelope strain can be used to determine the stress level at which deterioration due to cyclic loading began.

• The Journal of Korean Society of Virology
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• v.27 no.2
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• pp.209-216
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• 1997

Three dimensional structures of envelope protein from Korean isolates and Nakayama-NIH strain of Japanese encephalitis virus (JEV) were deduced by a computer program (HyperChem 4.0 Chemplus 1.0) based on the data of the three dimentional structure of Tick-borne encephalitis virus. In the three dimensional structure of envelope protein, neutralizing epitope and T-helper cell recognition site of C-terminal region of Korean isolates were structually similar to those of Nakayama-NIH but the N-terminal region was not. Korean JE isolates were compared with Nakayama-NIH strain by using cross-neutralization antibody test. Neutralizing activities of Korean isolates derived from guinea pigs were higher than those of Nakayama-NIH strain against Korean isolates, although the polyclonal antibody titers of Nakayama-NlH showed 1:160 to 1:640 against Korean isolates. According to the results from three dimentional structures and cross-neutralization analyses, the antigenic difference between Korean JE isolates and Nakayama-NIH strain may be dependent on structural difference of envelope protein.

• Molecules and Cells
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• v.40 no.5
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• pp.339-345
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• 2017

Retroviral and lentiviral vectors are mostly pseudotyped and often purified and concentrated via ultracentrifugation. In this study, we quantified and compared the stabilities of retroviral [murine leukemia virus (MLV)-based] and lentiviral [human immunodeficiency virus (HIV)-1-based] vectors pseudotyped with relatively mechanically stable envelope proteins, vesicular stomatitis virus glycoproteins (VSVGs), and the influenza virus WSN strain envelope proteins against ultracentrifugation. Lentiviral genomic and functional particles were more stable than the corresponding retroviral particles against ultracentrifugation when pseudotyped with VSVGs. However, both retroviral and lentiviral particles were unstable when pseudotyped with the influenza virus WSN strain envelope proteins. Therefore, the stabilities of pseudotyped retroviral and lentiviral vectors against ultracentrifugation process are a function of not only the type of envelope proteins, but also the type of viral internal core (MLV or HIV-1 core). In addition, the fraction of functional viral particles among genomic viral particles greatly varied at times during packaging, depending on the type of envelope proteins used for pseudotyping and the viral internal core.

• Journal of the Korean GEO-environmental Society
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• v.18 no.3
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• pp.25-30
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• 2017

This paper introduces a novel method to quantify the morphological evolution of the strain response envelope. The strain response envelope is defined as an image in strain increment space corresponding to the unit stress input in stress space. Based on the shape of strain response envelopes, the deformation characteristics of soils can be described using the framework of elastic-plastic theory. Fourier descriptor analysis was used to investigate the morphological characteristics of strain response envelopes. The numerical results show that when the stress input remains in the initial yield surface the Fourier descriptors remain constant. Once the stress input crosses the initial yield surface, every descriptors deals in this study change. Numerical and experimental results of this study show that clear yielding response is only found in natural block samples. Among the Fourier descriptors, the descriptor called as asymmetry is the best for detecting the yield and is minimally sensitive to the number of input stress paths.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.118-121
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• 2006

The research reported here is concerned with the effects of the fiber combination condition and water/cement ratio on the mechanical properties of high performance fiber-reinforced cementitious composites(HPFRCC). An experimental investigation of the behavior of steel cords(SC) and SC and Polyethylene(PE) hybrid fiber reinforced cementitious material under compressive and tensile loading is presented. In this experimental research, the tensile and compressive strength and strain capacity of HPFRCC were selected using the cylindrical specimens. The results show that W/C ratio is a significant effect factor on the compressive and tensile performance of HPFRCC. The envelope curve concept applies to hybrid fiber-reinforced cementitious composites in tension just as it does to compressive stress-strain curve of fiber-reinforced cement composites. For practical purposes, the tensile envelope curve may be taken to be the same as the monotonic tensile stress-strain curve.

• Structural Engineering and Mechanics
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• v.24 no.5
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• pp.585-599
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• 2006

This paper describes a series of laboratory tests carried out to evaluate the influence of bed joint orientation on interlocking grouted stabilised mud-flyash brick masonry under uniaxial cyclic compressive loading. Five cases of loading at $0^{\circ}$, $22.5^{\circ}$, $45^{\circ}$, $67.5^{\circ}$ and $90^{\circ}$ with the bed joints were considered. The brick units and masonry system developed by Prof. S.N. Sinha were used in present investigation. Eighteen specimens of size $500mm{\times}100mm{\times}700mm$ and twenty seven specimens of size $500mm{\times}100mm{\times}500mm$ were tested. The envelope stress-strain curve, common point curve and stability point curve were established for all five cases of loading with respect to bed joints. A general analytical expression is proposed for these curves which fit reasonably well with the experimental data. Also, the stability point curve has been used to define the permissible stress level in the brick masonry.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.04a
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• pp.87-90
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• 2004

In this paper, geometrically non-linear finite element analyses were performed to study the mechanical behavior of the material system of the envelope of stratospheric airships. The microstructure of the load­bearing plain weave layer was identified and modeled. The Updated Lagrangian formulation was employed to consider the geometric non-linearity as well as the induced structural non-linearity for the fiber tows. The stress-strain behavior was predicted and the effective elastic modulus was calculated by numerical experiments. It was found the non-linear stress-strain curves were largely different from those by linear analysis with much higher non-linear elastic moduli. The difference was more distinguishable when the tow waviness was smaller.

• Journal of Microbiology and Biotechnology
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• v.22 no.4
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• pp.470-478
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• 2012

Recent genome comparisons of E. coli B and K-12 strains have indicated that the makeup of the cell envelopes in these two strains is quite different. Therefore, we analyzed and compared the envelope proteomes of E. coli BL21(DE3) and MG1655. A total of 165 protein spots, including 62 nonredundant proteins, were unambiguously identified by two-dimensional gel electrophoresis and mass spectrometry. Of these, 43 proteins were conserved between the two strains, whereas 4 and 16 strain-specific proteins were identified only in E. coli BL21(DE3) and MG1655, respectively. Additionally, 24 proteins showed more than 2-fold differences in intensities between the B and K-12 strains. The reference envelope proteome maps showed that E. coli envelope mainly contained channel proteins and lipoproteins. Interesting proteomic observations between the two strains were as follows: (i) B produced more OmpF porin with a larger pore size than K-12, indicating an increase in the membrane permeability; (ii) B produced higher amounts of lipoproteins, which facilitates the assembly of outer membrane ${\beta}$-barrel proteins; and (iii) motility- (FliC) and chemotaxis-related proteins (CheA and CheW) were detected only in K-12, which showed that E. coli B is restricted with regard to migration under unfavorable conditions. These differences may influence the permeability and integrity of the cell envelope, showing that E. coli B may be more susceptible than K-12 to certain stress conditions. Thus, these findings suggest that E. coli K-12 and its derivatives will be more favorable strains in certain biotechnological applications, such as cell surface display or membrane engineering studies.

• Structural Engineering and Mechanics
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• v.9 no.4
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• pp.375-382
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• 2000

Experimental investigation into the cyclic behaviour of sand plast brick masonry was performed on forty two square panels. The panels were subjected to cyclic uniaxial compression for two cases of loading: normal to bed joint and parallel to bed joint. Experimental data were used to plot the unloading-reloading curves for the entire range of the stress-strain curve. Mathematical expressions to predict the reloading and unloading stress-strain curves at various values of residual strain are proposed. A simple parabola and an exponential type formula are found adequate to model the unloading and reloading curves respectively. The models account for the potential effects of residual strain on these curves. Comparison of test results with the proposed mathematical expression shows good correspondence.