• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.321-322
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• 2010

This paper suggest the new strength development model of concrete according to elapsed time for the performance model of domestic material.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.547-552
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• 2003

In mold machining, there are many concave machining regions where chatter and tool deflection occur since MRR (material removal rate) increases as curvature increases even though cutting speed and depth of cut are constant. Boolean operation between stock and tool model is widely used to compute MRR in NC milling simulation. In finish cutting, the side step is reduced to about 0.3mm and tool path length is sometimes over 300m. so Boolean operation takes long computation time and includes much error if the resolution of stock and tool model is larger than the side step. In this paper, curvature of CL(cutter location) surface and side step of tool path is used to compute the feedrate for constant MRR machining. The data structure of CL surface is Z-map generated from NC tool path. The algorithm to get local curvature from discrete data was developed and applied to compute local curvature of CL surface. The side step of tool path was computed by point density map which includes cutter location point density at each grid element. The feedrate computed from curvature and side step is inserted to new tool path to regulate MRR. The resultants wire applied to feedrate optimization system which generates new tool path with feedrate from NC codes for finish cutting. The system was applied to speaker mold machining. The finishing time was reduced to 12.6%. tool wear was reduced from 2mm to 1.1mm and chatter marks and over cut on corner were removed.

• Steel and Composite Structures
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• v.21 no.6
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• pp.1287-1306
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• 2016

The current research presents a buckling analysis of isotropic and orthotropic plates by proposing a new four variable refined plate theory. Contrary to the existing higher order shear deformation theories (HSDT) and the first shear deformation theory (FSDT), the proposed model uses a new displacement field which incorporates undetermined integral terms and involves only four variables. The governing equations for buckling analysis are deduced by utilizing the principle of virtual works. The analytical solution of a simply supported rectangular plate under the axial loading has been determined via the Navier method. Numerical investigations are performed by using the proposed model and the obtained results are compared with CPT solutions, FSDT solutions, and the existing exact solutions in the literature. It can be concluded that the developed four variable refined plate theory, which does not use shear correction coefficient, is not only simple but also comparable to the FSDT.

• Structural Engineering and Mechanics
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• v.90 no.5
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• pp.517-530
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• 2024

This paper presents a new four-unknown equivalent single layer (ESL) refined plate theory for the buckling analysis of functionally graded (FG) rectangular plates with all simply supported edges and subjected to in-plane mechanical loading conditions. The present model accounts for a parabolic variation of transverse shear stress over the thickness, and accommodates correctly the zero shear stress conditions on the top and bottom surfaces of the plate. The material properties are supposed to vary smoothly in the thickness direction through the rules of mixture named power-law gradation. The governing equilibrium equations are formulated based on the total potential energy principle and solved for simply supported boundary conditions by implementing the Navier's method. A numerical result on elastic buckling using the current theory was computed and compared with those published in the literature to examine the accuracy of the proposed analytical solution. The effects of changing power-law exponent, aspect ratio, thickness ratio and modulus ratio on the critical buckling load of FG plates under different in-plane loading conditions are investigated in detail. Moreover, it was found that the geometric parameters and power-law exponent play significant influences on the buckling behavior of the FG plates.

• The Journal of Korean Academy of Prosthodontics
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• v.34 no.4
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• pp.755-779
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• 1996

This study was designed to development of stock tray for Korean. The subjects for this study were 374 persons(male : 204, female : 170) with age $19{\sim}28$. The study models were made with irreversible hydrocolloid impression material and conventional stock tray, Individual trays were made on the study model and the master models were made after impression with polysulfide rubber impression material. Each of the master models measured 12 measuring points on the maxillary model and 13 measuring points on the mandibular model with digital sliding caliper. The values were analyzed statistically by SAS analysis. The measuring points were analysed and were consulted for the development of new stock tray for Korean. Maxillary models were divided into four groups acceding to the width between buccal alveolar ridges below the contact point of first molar and second molar. The size of new tray of the upper first group was 82mm (width), 60mm(length). That of the upper second group was 77mm (width), 59mm (length). That of the upper third group was 72mm (width), 58mm (length). And that of the upper fourth group was 67mm (width), 57mm (length). Mandibular models were devided into three group according to the width between lingual alveolar ridges below the second molar. The size of new tray on lower first group was 40mm (width), 55mm (length). That of the lower second group was 36mm (width), 55mm (length). And that of the third group was 32mm (width), 55mm (length). The author tested the fitness of newly designed stock tray in 52 subjects with normal occlusion and obtained good results that the problems of conventional stock tray were worked out.

• JSTS:Journal of Semiconductor Technology and Science
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• v.8 no.1
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• pp.92-97
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• 2008

In this Paper, we present a scaling theory for dual material surrounding gate (DMSGTs) MOSFETs, which gives a guidance for the device design and maintaining a precise subthreshold factor for given device parameters. By studying the subthreshold conducting phenomenon of DMSGTs, the effective conductive path effect (ECPE) is employed to acquire the natural length to guide the design. With ECPE, the minimum channel potential is used to monitor the subthreshold behavior. The effect of ECPE on scaling factor significantly improves the subthreshold swing compared to conventional scaling rule. This proposed model offers the basic designing guidance for dual material surrounding gate MOSFETs.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.644-647
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• 2003

Materials currently used as an injectable bulking agent in the dermatologic and urologic fields revealed several drawbacks such as particles migration, inflammatory reaction, allergic reaction, rapid volume shrinkage, and necessity of a donor site. In this study, we have developed injectable biomaterial comprising poly (DL- lactide-co-glycolide)(PLGA) and hyaluronic acid gel to overcome these problems. PLGA is a biocompatible synthetic material and hyaluronic acid is a common substance found in living organisms. We examined the feasibility of injection through needle and tested biocompatibility in animal model. After transplantation, injected sites and distant organs were examined histologically to verify a new tissue formation, inflammation, and particles migrations. Injected volume was maintained approximately 80 percent for 2 months. Results demonstrated that the developed material was injectable through various gauges of needles and induced a new bulking tissue formation without serious inflammatory reaction.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.648-652
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• 2004

A comparative investigation of an experimental and a simulation of chemical kinetics for NOx removal from dielectric barrier discharges is presented. Several types of dielectric barrier discharges were implemented depending upon the configuration of electrodes. The simulation was based on an approximate mathematical model for plasma cleaning of waste gas. The influence of non uniform distributions of species due to the production of primary active particles in the streamer channel was taken into account. A comparison of observed experimental to the calculated removal efficiency of NOx showed acceptable agreement.

• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.61-63
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• 2002

At recently, it is regarded efficiency of the electric motor. and the development of the electric motor of new concept and research according to the development of new material and a elevation of magnetic property of magnetism material have been processed actively. One of the that, the transverse flux linear electric motor is studing actively about application method in many ways. because it has high power density and efficiency more than a induction motor. In this study we introduce apply field of the electromotor which follows Picture and find out the characteristic using the 3D Finite Element Method(FEM).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.399-402
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• 1999

In this paper, a new method for calculating capacitance in arbitrarily shape structure is Presented. This new approach based on divergence theorem of Gauss\`s law is acheive by Surface-Contacted Element(SCE) for Gaussian surface. To evaluate accurate capacitance value in nonuniform electric field. in two dimensional analysis the interpolation using the elements which contact one nod (PE: Point-Element) or two nod (FE: Face-Element) is employed. Because the elements contacted with surface are very small compared with total elements in analytic model, SCE method has shorter computing time to calculate capacitance. This proposed method is verified by comparing the simulated results with value obtained by analytic method.