• 한국식품과학회지
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• 제51권2호
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• pp.188-191
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• 2019

In this study, the poor electro-transformant yield of large DNA in bifidobacteria was improved by increasing the DNA concentration, which was amplified by enhancing electroporation conditions: treating the cell wall weakening agent and cell membrane permeabilizing molecule as well as changing the electrical parameter. In the enhanced conditions, the electroporation frequency increased from 15 to 71 times compared to the initial conditions at the same DNA concentration. As the DNA concentration increased, the difference in the electroporation frequency between the two conditions became greater, and the curve of the enhanced conditions seemed to be saturated with a DNA concentration over $4{\mu}g$. The present study provided a clue to the recovery of the electroporation frequency with large DNA and formulated the relationship between the DNA concentration, the DNA size and the electroporation frequency in bifidobacteria. Therefore, this study will contribute to the expansion of molecular genetic studies of bifidobacteria.

• Advances in nano research
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• 제13권5호
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• pp.453-463
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• 2022

This paper aims to investigate the vibration analysis of functionally graded porous (FGP) beams using State-space approach with several classical and non-classical boundary conditions. The materials properties of the porous FG beams are considered to have even and uneven distributions profiles along the thickness direction. The equation of motion for FGP beams with various boundary conditions is obtained through Hamilton's principle. State-space approach is used to obtain the governing equation of porous FG beam. The comparison of the results of this study with those in the literature validates the present analysis. The effects of span-to-depth ratio (L/h), of distribution shape of porosity and others parameters on the dynamic behavior of the beams are described. The results show that the boundary conditions, the geometry of the beams and the distribution shape of porosity affect the fundamental frequencies of the beams.

• Structural Engineering and Mechanics
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• 제61권1호
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• pp.49-63
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• 2017

This paper presents an original hyperbolic (first present model) and parabolic (second present model) shear and normal deformation theory for the bending analysis to account for the effect of thickness stretching in functionally graded sandwich plates. Indeed, the number of unknown functions involved in these presents theories is only five, as opposed to six or even greater numbers in the case of other shear and normal deformation theories. The present theory accounts for both shear deformation and thickness stretching effects by a hyperbolic variation of ail displacements across the thickness and satisfies the stress-free boundary conditions on the upper and lower surfaces of the plate without requiring any shear correction factor. It is evident from the present analyses; the thickness stretching effect is more pronounced for thick plates and it needs to be taken into consideration in more physically realistic simulations. The numerical results are compared with 3D exact solution, quasi-3-dimensional solutions and with other higher-order shear deformation theories, and the superiority of the present theory can be noticed.

• Nuclear Engineering and Technology
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• 제36권1호
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• pp.12-23
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• 2004

In the present study a new measurement technique has been developed, which uses an ultrasonic transmission signal in order to identify the vertical two phase flow pattern. The ultrasonic measurement system developed in the present study not only provides the information required for the identification of vertical two phase flow patterns but also makes real time identification possible. Various vertical two phase flow patterns such as bubbly, slug, churn, annular flow etc. have been accurately identified with the present ultrasonic measurement system under atmospheric condition. In addition, the present test apparatus can practically simulate the ultrasonic propagation characteristics under high temperature and high pressure systems. Therefore, it is expected that the present ultrasonic flow pattern identification technique could be applicable to the vertical two phase flow systems under high temperature and high pressure conditions.

• Structural Engineering and Mechanics
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• 제45권3호
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• pp.355-371
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• 2013

Single- and multi-span orthotropic functionally graded hollow cylinders subjected to axisymmetrical bending are investigated on the basis of a unified shear deformable shell theory, in which the transverse displacement is expressed by means of a general shape function. To approach the through-thickness inhomogeneity of the hollow cylinder, a laminated model is employed. The shape function therefore shall be determined for each fictitious layer. To improve the computational efficiency, we resort to a transfer matrix method. Based on the principle of minimum potential energy, equilibrium equations are established, which are then solved analytically using the transfer matrix method for arbitrary boundary conditions. Numerical comparisons among a third-order shear deformable shell theory, an exact elastic theory and the present theory are provided for a simply supported hollow cylinder, from which the present theory turns out to be superior in stress estimation. Distributions of displacements and stresses in single- and three-span hollow cylinders with different boundary conditions are also illustrated in numerical examples.

• 한국산업융합학회 논문집
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• 제7권3호
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• pp.241-248
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• 2004

The purpose of the this paper is to consider the many dangerous factors involved in the use of temporary equipments in construction work and to reduce potential numerous fatalities by presenting suitable countermeasures. As a result of this study, the following conclusions and recommendations have been suggested. 1 Measures for safety sanitation must be strengthened in the field of machinery installation and engineering method. 2 The synthetic safety sanitation and safety control should be positively propelled. 3 An efficient safety training and education must be emphasized by the scientifical and systematical devices 4 A powerful precautionary countermeasure against health impediment should be conducted substantially 5. Miscellenous actions should be taken as follow. - Awaken enterprisers to the importance of their responsibility - Continuously conducting safety check.

• 교육녹색환경연구
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• 제12권3호
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• pp.50-57
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• 2013

The education of building services field at university is not enough, although the field has become to be very important in architectural engineering. This lack of education is one of the reason that the level of domestic building services field is lower than that in developed countries. Present conditions of related laws, fields of work after graduation and education at university in building services field have been studied, and education conditions have been investigated divided into four-year architectural engineering course and five-year architecture course. Though building services field has become more important at university education, the number of credits and professor of the field is still small than other fields of architectural engineering. More practical curriculums are necessary to meet the expectation of companies, and it will be one of the method to meet it that criteria of curriculum constitution is according to ABEEK(Accreditation Board for Engineering Education of Korea) in more architectural engineering department.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2005년도 춘계 학술발표회 논문집
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• pp.217-224
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• 2005

A higher order zig-zag shell theory is developed to refine the predictions of the mechanical and thermal behaviors partially coupled. The in-plane displacement fields are constructed by superimposing linear zig-zag field to the smooth globally cubic varying field through the thickness. Smooth parabolic distribution through the thickness is assumed in the out-of-plane displacement in order to consider transverse normal deformation and stress. The layer-dependent degrees of freedom of displacement fields are expressed in terms of reference primary degrees of freedom by applying interface continuity conditions as well as bounding surface conditions of transverse shear stresses. Thus the proposed theory has only seven primary unknowns and they do not depend upon the number of layers. In the description of geometry and deformation of shell surface, all rigorous exact expressions are used. Through the numerical examples of partially coupled analysis, the accuracy and efficiency of the present theory are demonstrated. The present theory is suitable in the predictions of deformation and stresses of thick composite shell under mechanical and thermal loads combined.

• Structural Engineering and Mechanics
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• 제55권3호
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• pp.495-510
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• 2015

Free vibration of non-uniform embedded nanoplates based on classical (Kirchhoff's) plate theory in conjunction with nonlocal elasticity theory has been studied. The nanoplate is assumed to be rested on two-parameter Winkler-Pasternak elastic foundation. Non-uniform material properties of nanoplates have been considered by taking linear as well as quadratic variations of Young's modulus and density along the space coordinates. Detailed analysis has been reported for all possible casesof such variations. Trial functions denoting transverse deflection of the plate are expressed in simple algebraic polynomial forms. Application of the present method converts the problem into generalised eigen value problem. The study aims to investigate the effects of non-uniform parameter, elastic foundation, nonlocal parameter, boundary condition, aspect ratio and length of nanoplates on the frequency parameters. Three-dimensional mode shapes for some of the boundary conditions have also been illustrated. One may note that present method is easier to handle any sets of boundary conditions at the edges.

• 한국재난정보학회 논문집
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• 제3권2호
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• pp.39-53
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• 2007

In modern society, the natural disaster damage is increasing by unusual weather conditions such as global warming. Many disaster victims in the disaster spot suffered from the heavy damages. In these conditions, this paper aims to improve of relief system in disaster. To achieve our aims, we analyzed the present disaster relief system in a legal, institutional aspect and disaster relief on the conceptual content, and look at the contents of the damage I have seen. And we are look at the issue of disaster relief, disaster relief measures to improve the present. In conclusion, this research suggests the improvements of the disaster relief system. First, Donations to secure transparency of the scheme passes. Second, the reality of actual expenses paid farmland. Third, recovery estimate by the reality. Fourth, when the disaster occurred, and the disaster of the itemized information. Finally, the degree of damage to the housing relief material support systems need improvement.