• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.3
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• pp.406-417
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• 1997

A numerical study was conducted on the optimum magnetic field intensity and asymmetric factor for uniform axial oxygen concentration in 8 inch silicon single crystal growing process by magnetic Czochralski method. For constant shape of cusp field, a change of coil and crucible position were compared. In case of symmetric cusp field, magnetic field intensity variation shows concave downward with crystal growing for uniform, axial oxygen concentration. A numerical results show similar value of standard deviation of average oxygen concentration for uniform oxygen concentration between coil and crucible position change. In case of asymmetric cusp field. asymmetric factor is increased with crystal growing to have uniform oxygen concentration.

• Steel and Composite Structures
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• v.22 no.6
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• pp.1359-1389
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• 2016

Buckling and free vibration behavior of a laminated cylindrical panel exposed to non-uniform thermal load is addressed in the present study. The approach comprises of three portions, in the first portion, heat transfer analysis is carried out to compute the non-uniform temperature fields, whereas second portion consists of static analysis wherein stress fields due to thermal load is obtained, and the last portion consists of buckling and prestressed modal analyzes to capture the critical buckling temperature as well as first five natural frequencies and associated mode shapes. Finite element is used to perform the numerical investigation. The detailed parametric study is carried out to analyze the effect of nature of temperature variation across the panel, laminate sequence and structural boundary constraints on the buckling and free vibration behavior. The relation between the buckling temperature of the panel under uniform temperature field and non-uniform temperature field is established using magnification factor. Among four cases considered in this study for position of heat sources, highest magnification factor is observed at the forefront curved edge of the panel where heat source is placed. It is also observed that thermal buckling strength and buckling mode shapes are highly sensitive to nature of temperature field and the effect is significant for the above-mentioned temperature field. Furthermore, it is also observed that the panel with antisymmetric laminate has better buckling strength. Free vibration frequencies and the associated mode shapes are significantly influenced by the non-uniform temperature variations.

• Journal of the Korean Society of Radiology
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• v.7 no.3
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• pp.227-232
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• 2013

The pixels used in a digital X-ray detector have different sensitivities and offset values. A non-uniform image is consequently obtained. Flat-field correction was introduced to resolve this problem and carried out image preprocessing in a digital imaging system. Nevertheless, the non-uniform images caused by several reasons have been being occasionally acquired. In this study, the non-uniform images acquired in digital imaging systems were applied to flat-field correction, and NPSs were calculated and analyzed with those images before and after correction. It was confirmed that low frequency noise were effectively eliminated.

• Fashion & Textile Research Journal
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• v.10 no.2
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• pp.228-235
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• 2008

The purpose of this study is to examine the functionality with material-improved working uniform(protocol, P) and current working uniform(control, C). Movement functionality evaluation of material-improved working uniform was carried out through sensory evaluation of working uniform. And Oxygen uptake was explored to different working uniform(P, C) in relation to a physiological functionality measurement. The results have been shown as follows: It was found that the workers feel uncomfortable with the parts of the wrist, the back width, the shoulder seam and the side in the current working uniform when they move their arms up and down, but the inconvenience has been reduced in the material-improved working uniform. And It was found that the workers feel uncomfortable with the parts of the back width, the wrist and the side seam of the jacket, and the waist, the hips and the thigh of the trousers in the current working uniform when they move their waist, but the inconvenience has been reduced in the material-improved working uniform. In the current working uniform, it was also found that they feel uncomfortable with the parts of the horse riding position in which they stand straight in their slightly bended knees, with the parts of the hips, the side seam, the thigh and the knees when they crouch down, and with the parts of the hips and the thigh when they put one of their legs onto a higher place. However, the inconvenience was reduced in the material-improved working uniform. Oxygen uptake, which was measured to assess physiological dressing functionality, was found to be higher when people work in an uncomfortable uniform than when they work in a uniform of better functionality by an increase in metabolic rate, which can be a cause of workers' inefficiency of fatigue.

• Honam Mathematical Journal
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• v.33 no.3
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• pp.381-391
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• 2011

One of the main interesting things of a matroid theory is the representability by a matroid from a matrix over some field F. The representability of uniform matroid $U_{m,n}$ over some field are studied by many authors. In this paper we construct a matrix representing $U_{3,6}$ over the field GF(4). Also we find out matrix of the affine matroid AG(2, 3) over the field GF(4).

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.968-971
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• 2002

Two decisive mechanisms of the electrorhological polishing for a small part(for example, a aspherical surface in a micro lens) are explained. Firstly, non-uniform electric field generated in the polishing structure increases a shear stress of ER fluids which is maximized dramatically near the tool, therefore, substrate adjacent to the tool can be removed effectively by mixed abrasives in the ER fluid. Secondly, abrasives in a non-uniform electric field are governed by the dielectrophoretic phenomena. Abrasives move toward the tool because the field gradient is highest near the tool and then abrasives are actively holded in that area. This phenomena is observed and evaluated by the optical measurement.

• Bulletin of the Korean Chemical Society
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• v.24 no.12
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• pp.1827-1831
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• 2003

Field emission of carbon nanotubes (CNTs) fabricated by disproportionation of CO has been studied. CNTs fabricated on well-ordered Co nanowire arrays formed on the porous anodic aluminum oxide templates were well graphitized, uniform in diameter and aligned vertically with respect to the plane of the template, and showed a good field emission property. Very uniform emissions were observed from the CNTs fabricated at relatively low temperature, $500-600^{\circ}C$. Low fabrication temperature such as $500^{\circ}C$ could make it possible to fabricate CNTs on soda lime glass, a low-cost substrate, for display panel.

• Journal of Environmental Science International
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• v.7 no.3
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• pp.349-360
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• 1998

Effects of uniform flow on a two-dimensional mesoscale horizontal convection were investigated by using the vorticity and thermodynamic equations. For thins purpose, We simulated properties of a thermal convection m a stably stratified Boussinesq flued caused by partial heating at the center of a lower boundary If we don't consider effects of the uniform flow, the convection takes the form of aidsymmetrlc with respect to the z-alds. But when uniform flow Is strong, velocity field and temperature field consist of a sin91e cell structure which spreads upstream side of the partial heating area. The flow pattern for strong uniform flows takes the form of positive temperatue near the ground and negative temperature perturbation soft over the partial heating area, and downward motion directly over the upwind portion of the partial heating area and upward motion on the downstream side. The downstream edge of the upstream cell Is shifted in the downstream direction with the Increase of uniform flow almost linearly.

• 전기의세계
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• v.27 no.2
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• pp.64-68
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• 1978

By applying the streamer breamer breakdown criterion and the surface roughness factor, the effet of field distortion due to conductor surface roughness on breakdown is investigated theoretically in a uniform-field of compressed SF$_{6}$. It has been shown that the streamer constant has a significant influence on the threshold of breakdown and different shapes of protrusions do not result in different thresholds of breakdowns. Moreover, uniform-field tests can give results which apply to e-ratio coaxial-electrode systems of practical dimensions, and may offer some advantages compared with coaxial-electrode tests.s.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.9
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• pp.964-975
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• 1990

This paper aims at the design of high voltage electrode contour under specified field condition. Defining the contour with B-Spline curve, the number of contour variables can be reduced and very smooth electrode can be obtained. For the analysis of the electric field, Surface Charge Method which has advantages in practical model has been used. As an initial contour, the rod-plane gap has been used since the difference between maximum and minimum field value is relatively large. Various field conditions including uniform field condition are given to the end of the rod electrode. Under uniform field condition, authors designed an electrode whose field-deviation was under 0.5%. Finally, the relation between the curvature and field of the electrode has been checked, which showed that B-Spline curve is appropriate for the shape function.