• 한국연소학회:학술대회논문집
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• 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
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• pp.225-228
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• 2012

Thermodynamic and economic analysis on various type of gas turbine combined cycle power plants was presented to build up the criteria for optimization of power plants. The efficiency considered about energy level difference between electricity and heat was introduced. The efficiency on power and heat generation of power plants whose have different purpose was estimated and power generation costs on various type of combined heat and power plants : fired/unfired, condensing/non-condensing mode, single/double pressure HRSG.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -2
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• pp.941-944
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• 2000

This paper proposes, for the first time, the design of class I pull-push power amplifier. With the new design, the output power is increased by four times when compared to conventional single-end class I connection amplifier with the same supply voltage. The performance of the proposed amplifier is verified by with a 100-kHz power amplifier constructed using general-purpose NPN transistors.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.2034-2036
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• 2005

Four Point Probe 방법을 이용한 반도체 wafer의 면저항 측정을 위하여 single configuration 기술을 적용한 회로를 설계 제작하였으며, 제작된 FPP장치의 면저항 측정범위는 $10{\sim}3000{\Omega}/sq.$ 이고 측정의 정확도는 약 0.5%이하이다.

• Journal of the Optical Society of Korea
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• 제6권2호
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• pp.21-26
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• 2002

Interferometric metrology with a null CGH(computer-generated hologram) is presented for measuring highly aspheric surfaces used in a large screen projection television system with high accuracy. The cubic spline surface model which works in a single-pass configuration with a refractive index of object space 0 is used for designing a null CGH. A hybrid null corrector with plano-concave lens in front of a CGH is presented to make the CGH easier to fabricate. Experimental results are presented to demonstrate the validity of the proposed technique.

• Journal of Magnetics
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• 제12권2호
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• pp.72-76
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• 2007

We investigate the spin transfer torque in metallic multilayer system by employing Keldysh non-equilibrium Green function method. We study the dependences of the spin transfer torque on the detailed energy configuration of ferromagnetic, spacer, and lead layers. With Keldysh non-equilibrium Green function method applied to a single band model, we explore spin transfer torque effect in various layer structures and for various material parameters.

• 한국정밀공학회지
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• 제17권10호
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• pp.192-199
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• 2000

The design of multi-stage gear drives is a time-consuming process because it includes more complicated problems, which are not considered in the design of single-stage gear drives. The designer has no determine the number of reduction stages and the gear ratios of each reduction stage. In addition, the design problems include not only dimensional design but also configuration design of gear drive elements. There is no definite rule or principle for these types of design problems. Thus the design practices largely depend on the sense and the experiences of the designer, and consequently result in undesirable design solution. A new and generalized design algorithm has been proposed to support the designer at the preliminary phase of the design of multi-stage gear drives. The proposed design algorithm automates the design process by integrating the dimensional design and the configuration design process. The algorithm consists of four steps. In the first step, the user determines the number of reduction stages. In the second step, gear ratios of every stage are chosen using the random search method. The values of the basic design parameters of a gear are chose in the third step by using the generate and test method. Then the values of the dimensions, such as pitch diameter, outer diameter and face width, are calculated for the configuration design in the next step. The strength and durability of each gear is guaranteed by the bending strength and the pitting resistance rating practices by using AGMA rating formulas. In the final step, the configuration design is carried out using simulated annealing algorithm. The positions of gears and shafts are determined to minimize the geometrical volume (size) of a gearbox while avoiding interferences between them. These steps are carried out iteratively until a desirable solution is acquired. The proposed design algorithm is applied to the preliminary design of four-stage gear drives in order to validate the availability. The design solution has considerably good results in both aspects of the dimensional and the configuration design.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 F
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• pp.1993-1998
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• 1997

This paper presentes a novel single-phase unity power factor rectifer, which features Critical Conduction Mode and ZVS. The reduced conduction losses are achieved by the employment of a single converter instead of the typical configuration composed of a front end rectifier followed by a boost converter. Theoretical analysis, a design example and experimental results of a 300 converter with $127V_{rms}$ input voltage and 400 VDC output voltage are presented.

• International Journal of Fluid Machinery and Systems
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• 제6권3호
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• pp.121-136
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• 2013

This paper reports the 1-D fluid transient simulation results of the discharge flow conditions in a 6-cylinder reciprocating slurry pump. Two discharge manifold configurations are studied comparatively; a case with a hexagon shaped discharge manifold where each cylinder discharges at a single vertex, and a case where all the cylinders discharges are lumped together into a tank shaped manifold. In addition, the study examines the effect of two pulsation mitigation measures in the case of hexagonal manifold; a single inline orifice in one of the hexagon sides and a volumetric dampener at the manifold outlet. The study establishes the pressure and flow fluctuation characteristics of each configuration and decouples the pulsation characteristics of the pump and the discharge manifold.

• Progress in Superconductivity
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• 제5권1호
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• pp.9-12
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• 2003

We observed the splitting of the fluxon-flow branches in the current-voltage characteristics of serially stacked intrinsic Josephson junctions (IJJs) formed in $Bi_2$$Sr_2$$CaCu_2$$O_{ 8＋x}$ single crystals in the long-junction limit. Stacks of IJJs were sandwiched between two Au electrodes deposited on the top and the bottom of the stack using the ‘double-side cleaving technique’. In all the samples studied, the branch splitting started occurring for a dense fluxon configuration around 2 T and became more distinct in a higher magnetic field range. This observation can be explained in terms of switching between different Josephson fluxon modes in resonance with the collective plasma oscillations induced by both inductive and capacitive coupling between stacked IJJs. This is the first detailed and quantitative identification of the coherent flux-flow modes in stacked..

• 전기학회논문지
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• 제56권1호
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• pp.156-160
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• 2007

Surface plasmon resonance(SPR) has been widely studied for biological and chemical sensing applications. The present study conducts numerical simulation for the single and bimetallic layer SPR configurations by using the multiple beam interference matrix(MBIM) method to investigate the influence of wave interference and complex refractive indices of materials on optical characteristics such as reflectance and optical phase shift which are used for sensing. First, calculated reflectances are compared with experimental data for validation. In addition, in the single film structures this study finds out the appropriate film thicknesses with minimum reflectance for cases of gold film and silver film. For a bimetallic silver-gold film structure, in particular, the bimetallic film thicknesses that has the minimum reflectance are found 36 nm for silver and 5 nm for gold. From the results, the use of phase shift would be useful compared to reflectance in determining the SPR configuration because the phase shift becomes more sensitive than reflectance.