• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.50 no.6
• /
• pp.263-272
• /
• 2001

The paper presents the design of a segmented type synchronous reluctance motor(SynRM) to increase its torque and power factor. The main feature of a segmented type synchronous reluctance motor is the flux barrier. Thus, the design process to find optimum value of various geometric parameters including flux barrier will be explained. Optimum value of each parameter is found where the d, q inductance difference and saliency ratio are maximized because these inductance characteristics are related to torque and power factor. Finite Element Analysis will be used to simulate motor characteristics. Analysis results of redesigned SynRM show higher saliency ratio over 10 and improved value of maximum power factor.

• Journal of Mechanical Science and Technology
• /
• v.20 no.3
• /
• pp.319-328
• /
• 2006

A simple approximation method for the stress intensity factor at the tip of the axial semielliptical cracks on the cylindrical vessel is developed. The approximation methods, incorporated in VINTIN (Vessel INTegrity analysis-INner flaws), utilizes the influence coefficients to calculate the stress intensity factor at the crack tip. This method has been compared with other solution methods including 3-D finite element analysis for internal pressure, cooldown, and pressurized thermal shock loading conditions. For these, 3-D finite-element analyses are performed to obtain the stress intensity factors for various surface cracks with t/R=0.1. The approximation solutions are within $\pm2.5%$ of the those of finite element analysis using symmetric model of one-forth of a vessel under pressure loading, and 1-3% higher under pressurized thermal shock condition. The analysis results confirm that the approximation method provides sufficiently accurate stress intensity factor values for the axial semi-elliptical flaws on the surface of the reactor pressure vessel.

• Journal of Electrical Engineering and Technology
• /
• v.9 no.1
• /
• pp.178-183
• /
• 2014

This paper presents a motor characteristics analysis method using an equivalent circuit. Motor characteristics analysis via equivalent circuit is very important for designing a high efficiency single phase induction motor. The accuracy of the motor characteristics depends on the accuracy of the parameters, especially saturation factor, which determines the cyclical relationship in the analysis process. Therefore, using the proposed method, the saturation factor was calculated using the iteration routine and numerical technique. The proposed method was verified by comparing the finite element method results and the dynamo test results of manufactured prototype model.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.05c
• /
• pp.19-24
• /
• 2001

In this study, Pb(La Ce)$TiO_3$ composition ceramics were manufactured for 20 MHz resonator application. Electromechanical coupling factor, mechanical quality factor and dynamic range of thickness vibration mode were measured as the variations of L/T(length/thickness) ratio of ceramic substrats. Mechanical quality factor and dynamic range of third overtone thickness vibration mode showed the highest value of 2,773 and 52.22 dB at specimen S4(l/t=12), respectively. The excellent temperature stability of resonant frequency suitable for resonator application was shown, regardless of thermal shock.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.14 no.9
• /
• pp.720-725
• /
• 2001

In this study, Pb(La,Ce)Ti $O_3$ ceramics were manufactured for 20 MHz resonator application. Electromechanical coupling factor( $k_{t}$, $k_{t3}$, mechanical quality factor( $Q_{mt}$ , $Q_{mt3}$ and dydnamic range (D.R) of thickness vibration mode were measured as the variations of $\ell$/t(length/thickness) ratio of ceramic substrates. Mechanical quality factor( $Q_{mt3}$) and dynamic range of third overtone thickness vibration mode showed the highest value of 2,773 and 52.22dB at specimen S4($\ell$/t=12), respectively. The excellent temperature stability of resonant frequency suitable for resonator application was shown, regardless of thermal shock.k.ock.k.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.10 no.3
• /
• pp.348-357
• /
• 1998

The flow characteristics inside U-bend tube of the laminated plate heat exchanger were numerically investigated. The behavior of fluid flow, and the variations of the faulty area and friction factor are examined according to the distance between the span and the wall and the diameter of the round attacked to the end of span. The results show that the diameter(d) of the round attached to the span is mainly associated with the smooth circulation of fluid flow rather than the size of faulty area and the friction factor. As the distance($\ell$) between the span and the wall decreases, the faulty area decreases, however the friction factor dramatically increases. It is also found that one can obtain a good result in the view of the flow characteristics and pressure drop at d=7.5mm and $\ell$=30.5mm.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.24 no.8B
• /
• pp.1456-1463
• /
• 1999

This paper describes the measurement system of antenna factor using standard antenna method in OATS(Open Area Test Site) of KRISS(Korea Research Institute of Standards and Science) and methods for reducing an environmental noise affecting antenna factor. The range of measurement frequency is 30 - 1000 MHz, all control and data acquisition were done by computer automatically. Measurement results of antenna factors are presented, total uncertainty of antenna factor is $\pm$1 dB.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.20 no.5
• /
• pp.494-502
• /
• 1991

Diazotized chitin(CHITN) as supports of immobilized enzyme, which was obtained by alkaline hydrolysed chitin with NaN3 and HCI was employed to produce CHITN-Gase with glutaraldehyde as bifunctional reagent. Activities of CHITN-Gase were determined with reaction of p-nitro-pheol-$\beta$-D-glucopyranoside(PNG) in plug flow reactor as a reference of CHITA-Gase. Their optimum temperature, pH, Km and Vmax, mass transfer coefficient (h), effctiveness factor(η)were plotted with variation of flow rate and H/D. Mass transfer coefficient(h) of those enzymes increased because of their flux, as flow rates were increased and controlled by reaction rate. Effectiveness factor(η) of both enzymes were nearly 1.0.

• Structural Engineering and Mechanics
• /
• v.59 no.1
• /
• pp.15-36
• /
• 2016

The components of the seismic behavior factor of RC frames are expected to change as structural redundancy increases. Most researches indicate that increasing redundancy is desirable in response to stochastic events such as earthquake loading. The present paper investigated the effect of redundancy on a fixed plan for seismic behavior factor components and the nonlinear behavior of RC frames. The 3D RC moment resistant frames with equal lateral resistance were designed to examine the role of redundancy in earthquake-resistant design and to distinguish it from total overstrength capacity. The seismic behavior factor and dynamic behavior of structures under natural strong ground motions were numerically evaluated as the judging criteria for structural seismic behavior. The results indicate that increasing redundancy alone in a fixed plan cannot be defined as a criterion for improving the structural seismic behavior.

• Proceedings of the KIEE Conference
• /
• 1995.07b
• /
• pp.941-943
• /
• 1995

The convergence of adaptive algorithm depends mainly on the proper choice of the design factor called the covergence factor. In the paper, an optimal convergence factor involved in TRLMS algorithm, which is used to predict the coefficients of the ARMA predictor in ADPCM is presented. It is shown that such an optimal value can be generated by system signals such that the adaptive filter becomes self optimizing in terms of the convergence factor. This algorithm is applied to real image.