• Proceedings of the Optical Society of Korea Conference
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• 2001.02a
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• pp.20-21
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• 2001

광결정(photonic crystal)은 빛의 파장 크기 정도의 격자 상수를 지닌 1차원, 2차원, 또는 3차원의 주기적인 구조이다. 최근에 2차원 광결정 공진기 구조에서 광펌핑으로 레이저 발진이 성공한 결과가 발표되면서 광결정 구조를 이용한 광소자로의 응용이 본격적으로 시작되고 있다. 하지만, 2차원 광결정 발광 구조에서는 능동 매질이 공기 중과 접한 영역이 넓어서 필연적으로 면에서의 비발광 결합이 중요한 문제가 된다. 이러한 문제 때문에 반도체에 기반한 광결정 구조 중에서는 비발광 결합이 비교적 적은 InP/InGaAsP 계열 물질이 능동 매질로 이용되어 왔다. 본 연구에서는 광결정 발광 구조에서 표면 비발광 결합이 실제로 어느 정도나 영향을 미치는가에 대한 연구를 수행하였다. (중략)

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1994.10a
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• pp.55-63
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• 1994

The analysis of superplastic sheet forming process is studied by the use of the finite element method using a convected coordinate system and a skew boundary condition. In the formulation, the large inelastic behavior of the superplastic material is described as incompressible, nonlinear, viscous flow. The formulation is then approximated to the finite dimensional space with the use of membrane elements, which results in algebraic linear equations. In addition to the finite element formulation, a pressure cycle control algorithm is combined in the analysis for optimization of the forming time, which deals with the maximization of the strain rate sensitivity, the protection of the thickness reduction, the consistency of the desired strain rate and improvement of formability.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.437-440
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• 2009

In this paper, an aluminum ring forging process of manufacturing an optimized perform for a hot forging process is simulated using AFDEX 3D, a general-purpose metal forming simulator based on rigid-thermoviscoplastic finite element method. Non-isothermal analysis is carried out and the predictions are compared with the experiments in terms of dimensional accuracy. It was shown that the predictions are in good agreement with the experiments.

• Solar Energy
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• v.19 no.3
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• pp.93-100
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• 1999

The objective of this experimental study was to investigate the characteristics of heat transfer and air flow in two-dimensional impinging jet system, in which hybrid rods have been set up in front of heating surface in order to increase heat transfer. The shape of hybrid rods had a cross section made with a half of circular cross section and that of rectangular. This time, the clearance from hybrid rod to heating surface(C=1, 2, 4mm) and the pitch between each hybrid rods(P=30, 40, 50mm) changed for the transition region(H/B=10). And this result compared with the experimentation without hybrid rod. As a result, heat transfer performance was best under the condition of C=1mm, in case clearance changed, and as the pitch is 30mm, it is largely influenced by eddies and acceleration in case pitch of hybrid rod changed.

• Journal of Integrative Natural Science
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• v.10 no.1
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• pp.20-26
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• 2017

Chemerin receptor, which predominantly expressed in immune cells as well as adipose tissue, was found to stimulate chemotaxis of dendritic cells and macrophages to the site of inflammation. Chemerin is a widely distributed multifunctional secreted protein implicated in immune cell migration, adipogenesis, osteoblastogenesis, angiogenesis, myogenesis, and glucose homeostasis. Recent studies suggest chemerin may play an important role in the pathogenesis of obesity and insulin resistance and it becomes a potential therapeutic target for treating type II diabetes. The crystal structure of chemerin receptor has not yet been resolved. Therefore, in the present study, homology modelling of CMKLR1 was done utilizing the crystal structure of human angiotension receptor in complex with inverse agonist olmesartan as the template. Since the template has low sequence identity, we have incorporated both threading and comparative modelling approach to generate the three dimensional structure. 3D models were generated and validated. The reported models can be used to characterize the critical amino acid residues in the binding site of CMKLR1.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.2027-2030
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• 2002

SFFS(Solid Freeform Fabrication System) is commercializing to rapid prototyping concept in world- wide some corporations including the U.S.A, have much technological problems yet and need new mode for agile solid freeform fabrication as well as prototyping. In this paper, we design an algorithm that the cutting path of laser beam, on the SFFS, is controlled with constant speed. The designed algorithm fer constant-speed path control is implemented and experimented in the CAFL$\^$VM/ (Computer Aided Fabrication of Lamination for Various Material) system, the new SffS which is developed in this paper. Finally, the ceramic, new material developed in this paper, cut and fabricated. The dimensional accuracy and mechanical stability of the 3D object is confirmed through the experiment, also.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.3
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• pp.89-95
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• 1996

In this ppaer, temeprature dependent transport and heat transport models have been incorperated to the two dimensional device simulator SNU-2D provides a solid bse for nonisothermal device simulation. As an example to study the nonisothermal problem. we consider SOI MOSFET's I-V characteristics have been simulated and compared with the measurements. It is shown that negative slopes in the Ids-Vds characteristics are casused by the temperature dependence of the saturation velocity and the degradation of the temperature dependence mobility. Also it is shown that the kink effect occurs when impact ionization near the drain produces a buildup of holes in this isolated device island, and the hysteresis is caused by the creation of holes in the channel and their flow to the source.

• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.4
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• pp.451-456
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• 2014

A compact model of a depletion-mode silicon-nanowire (Si-NW) pH sensor is proposed. This drain current model is obtained from the Pao-Sah integral and the continuous charge-based model, which is derived by applying the parabolic potential approximation to the Poisson's equation in the cylindrical coordinate system. The threshold-voltage shift in the drain-current model is obtained by solving the nonlinear Poisson-Boltzmann equation for the electrolyte. The simulation results obtained from the proposed drain-current model for the Si-NW field-effect transistor (SiNWFET) agree well with those of the three-dimensional (3D) device simulation, and those from the Si-NW pH sensor model also agree with the experimental data.

• International Journal of Fluid Machinery and Systems
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• v.4 no.1
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• pp.97-103
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• 2011

With the aim to increase blade loadings and stable operating range in highly loaded compressors, this article has been conducted to explore, through a numerical parametric study, the potential of passive control using slotted bladings in cascade configurations. The objective of this numerical investigation is to analyze the influence of location, width and slope of the slots and therefore identify the optimal configuration. The approach is based on two dimensional cascade geometry, low speed regime, steady state and turbulent RANS model. The results show the efficiency of this passive technique to delay separation and enhance aerodynamic performances of the compressor cascade. A maximum of 28.3% reduction in loss coefficient have been reached, the flow turning is increased with approximately $5^0$ and high loading over a wide range of angle of attack have been obtained for the optimized control parameter.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1614-1622
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• 2008

A series of three-dimensional numerical modelling have been conducted to clarify the behaviour of multi-pressurised soil nails with high strength steel pipes. In this study, the soil non-linearity, the soil-nail interaction and staged construction are considered. It has been found that pressurised soil nails can reduce lateral ground movement by 14-21% compared to general soil nails with very low pressure. In addition, ground settlement was reduced when using multi-pressurised soil nails. The pressurised soil nail may result in an increase in the surcharge loading on the ground surface.