• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.603-606
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• 2002

Numerical analysis and its inverse design process of 2nd stage of JT8D aircraft engine is described. One of the most important factors that affect the performante of turbomachine is secondary flow in the blade passage, so that the performance of turbomachine can be improved by controlling secondary flow. In this paper, as a method to control secondary flow, commercial inverse design program, TurboDesign is used. Meridional derivative of angular momentum is selected as a parameter to control blade leading in this program, To validate inverse designed model, computational analysis is applied which includes rotor-stator-interaction. In this paper, CFB results of both original and inverse designed model are compared to examine how much the performance improves without reduction of work output.

• 한국전기전자재료학회논문지
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• 제29권10호
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• pp.630-634
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• 2016

In this paper, we analyzed the power consumption and the accumulated energy in HTSC (high-TC superconducting elements) according to the resistance of HTSC element and the winding current of transformer type SFCL (superconducting fault current limiter) using double quench. For the analysis, two different inductances of the one secondary winding among two secondary windings comprising the transformer type SFCL were selected and the short-circuit tests were carried out. The consumed power and the accumulated energy in HTSC element connected into the secondary winding with larger inductance were analyzed to be larger compared to the one connected into the secondary winding with lower inductance.

• Architectural research
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• 제13권1호
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• pp.25-32
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• 2011

The purpose of this research is to investigate the effect of specific hydration reaction on the stiffening process of cement paste. The cement compositions are manipulated to cause specific hydration reactions (secondary gypsum and syngenite formation) responsible for false set, and the relationship between specific hydration reactions and the flow and stiffening behavior of cement paste were investigated using modified ASTM C 403 penetration resistance measurement and oscillatory shear rheology. X-ray powder diffraction (XRD) was used for the phase identification associated with premature stiffening of cement paste. Differential thermal analysis (DTA) and thermogravimetric analysis (TGA) were used for verification of syngenite formation. From the results, both secondary gypsum and syngenite formation caused faster stiffening and set. The amount of syngenite produced during 1 hour hydration was approximately 1 % of total mass of the cement paste, but cement paste with syngenite formation showed significantly accelerated stiffening behavior compared to normal cement paste.

• 수산해양교육연구
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• 제22권1호
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• pp.11-24
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• 2010

The purpose of this study was to analyze the needs of the preservice secondary school teacher on understanding of international society and curriculum of international understanding and to derive the implications on developing curriculum of international understanding. This study used a questionnaire survey. The results are summarized as follows. First, it seems to be necessary to develop curriculum for satisfying the higesconcerns on worldsculture of preservice secondary school teacher. Second, the curriculum of educating international understanding for preservice secondary school teacher should contain such contents as multiple cultures, multiple perspectives, global relations and instructional materials. Third, it is necessary that instructions on educating international understanding should employ experience of global culture, discussion, lecture and so on.

• 한국해양공학회지
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• 제16권2호
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• pp.27-31
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• 2002

The purpose of this study is to investigate the variation of resonance that is possible caused by construction of new port in a practical sea area between the existing port and the new one. The research of amplification that of the sea area was accomplished for the variation of resonance. In this study, long period wave that is observed continuously in the practical sea area was analyzed, and then secondary undulation was reproduced by numerical analysis. As a result of numerical analysis, the first mode resonant periods in the existing port is 640sec, and in the new one is 500sec. On the other hand, we know there is long period wave of 500sec from analyzation of field datas. Because that period this period is the resonant period in the new port. There is also the possibility of secondary undulation cause of resonant.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 A
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• pp.136-138
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• 1999

Linear Induction Motors (LIMs) with the long secondary conductor often have joints between the segmented secondary, which are specially used for magnetically levitated high-speed vehicle and elevators. In this paper, the dynamic characteristics of the LIM with joints in the secondary are investigated using the time-stepping finite element analysis. It is supposed that both aluminium conductor and back-iron have joint in the active zone during the analysis. As a result, thrust and normal force ripple which have effects on the motor dynamics and vibration are examined.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 B
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• pp.803-805
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• 2004

This paper proposes the calculation method of magnetic coupling coefficient of the contact-less energy transmission system by 3D finite element method with a variation of the secondary core positions. The primary, secondary self and leakage inductances and the capacitances of a resonant circuit are calculated by the finite element analysis results. From these values, the magnetic coupling coefficients are obtained. The secondary voltages and currents at the secondary core positions are calculated by using the resonant circuit and compared.

• 연구논문집
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• 통권22호
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• pp.39-46
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• 1992

A dynamic design process was proposed for the design of the secondary suspension characteristics of a magnetically levitated vehicle(MAGLEV). It is based on a ride quality-secondary stroke trade-off. For the vertical vibration analysis, a magnetically levitated vehicle was simplified as 2 d.o.f. linear model, and FRA's class-6-track irregularities were considered as exciting disturbances. The optimum value of airspring stiffness and damping coefficient for the secondary suspension of a prototype MAGLEV was determined using this proposed design process.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부A
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• pp.7-9
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• 1998

In this paper, dynamic characteristics analysis of linear induction motor with joints in the secondary conductor is discussed. The time stepped finite element method and moving mesh technique are used for simulation. ${\nabla}{\phi}$ of jointed secondary conductor is defined for simulation, respectively. Simulation results have shown that joints in the secondary conductor affect thrust ripple and attractive force ripple.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.919-924
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• 2005

Fretting-wear caused by turbulence excitation for KSNP(Korea standard nuclear power plant) steam generator is investigated numerically. Secondary sides density and normal velocity are obtained by the thermal-hydraulic data of the steam generator. Because nonlinear finite element analysis is complex and time consuming, work rate is estimated by using linear analysis for simple straight 2-span tube. Wear volume and depth by using work rate calculation are estimated. Span length, secondary side fluid density and normal velocity are adopted to study the effects on the fretting-wear by turbulence excitation. When secondary sides density and normal velocity is increased, It turns out that secondary side density and normal gap velocity are very important paramater for fretting-wear phenomena of the steam generator.