• Journal of the korean Society of Automotive Engineers
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• v.10 no.2
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• pp.61-69
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• 1988

The finite-difference three-dimensional boundary layer procedure of Chang and Patel is modified and applied to solve the boundary layer development on the automobile surface. The inviscid pressure distribution needed to solve the boundary layer equations is obtained by using a low order panel method. The plane of symmetry boundary layer exhibits the strong streamline divergence up to the midbody and convergence thereafter. The streamline divergence in front of the windshield helps the boundary layer to overcome the sever adverse pressure gradient and avoid the separation. The relaxation of the pressure right after the top of the wind-shield, on the other hand, makes the overly thinned boundary layer to readjust and prompts the streamlines to converge into the symmetry plane before the external streamlines do. The three-dimensional characteristics are less apparent after the midbody and the boundary layer is similar to that of the two-dimensional flow. The results of the off-plane-of-symmetry boundary layer are also presented.

• Journal of Institute of Convergence Technology
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• v.9 no.1
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• pp.25-30
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• 2019

Normal cranes cannot be used to move the fan inside the high-rise factories. Due to the size of the fan and safety accidents, there is a need for a structure capable of lifting and transporting. In this study, the safety of the structure was evaluated by considering the center of gravity of the fan and the effect of the fan being tilted up. An analysis of the buckling was performed by hand calculation. Nonlinear analysis was performed using ABAQUS to evaluate the safety of the structure. The safety factor for buckling is above 4.0 and the safety factor for stress is calculated to be 1.31 under the worst load distribution conditions.

• Bulletin of the Society of Naval Architects of Korea
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• v.22 no.3
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• pp.1-8
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• 1985

In this paper, the motion response and wave load of a container ship are treated by a nonlinear motion theory, which is similar to that used by Yamamoto et. al.[1]. This paper deals with the vertical motion response in oblique waves and the effect of the Smith correction in buoyancy force calculation. In the present computation, for S-175 container ship model our result also shows that the ratio of the motion peak to peak value to the wave height decreases as the wave height increases, which was obtained earlier by Yamamoto et.al.[3]. On the other hand the nondimensional midship bending moment increases as the wave height increases. These nonlinear effects are dominant near the resonance frequency, and depend on the hull form and forward speed. However, it is found that these nonlinear effects are significant for tanker model.

• Journal of the Korean Ceramic Society
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• v.23 no.2
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• pp.64-70
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• 1986

In this investigation x-ray diffraction method was mainly studied for quantitative analysis of clinker mineral composition. And also optical microscopic observation and Bogue calculation method were applied to compare with the x-ray diffraction method. In the procedure of x-ray diffraction analysis graphite monochromator automatic divergence slit and spinner for sample holder were used for minimizing the error due to the operation of the equipment. Especially the separation of overlapped peaks were proceeded by micro-processor automatically. The results of x-ray diffraction method for synthesized clinker were consistent with the Bogue value and the results of optical microscopic observation. However the results of quantitative analysis of mineral composition or commercial clinker containing solid solution of minor component were different from the Bogue value. On the other hand they agreed reasonably well with results of the optical mic-roscopic observation.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1313-1318
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• 2007

Recently, the terror frequently has taken place for unspecified individuals as modern society is complicated. Especially, in case of a subway carriage fire as Daegu subway fire, because smoke spread path usually coincide with passenger's evacuation path, it will reduce visibility and can cause fatalities by asphyxiation. This study performs not only fire simulation with CFAST V6 but also evacuation simulation with EXODUS V4 for the purpose of taking measures for passengers's life safety in subway fire. As a result of evacuation simulation without fire, evacuation times are 36 s for EXODUS V4 and simple hand calculation, and when fire is occurred fire, 101 persons evacuated in 32 s. Therefore, a countermeasure of evacuation in subway carriage fire is required to repression of fire and emergency exit.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.2 no.3
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• pp.199-207
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• 1990

Inviscid flows in a radial turbomachine and its performance are predicted by using a pannel method. Possibility of the method to be used for design purpose is investigated. The flows in a radial turbomachine are reasonably simulated with several off-design flow rates. The diameter ratio of the rotor and inlet and outlet vane angles are systematically changed so that performance of the machine in various designs are predicted. All the predictions are shown to be in the range of Cordier curve. On the other hand, calculated slip factors are also in good agreement with values given by an empirical formula.

• Asian-Australasian Journal of Animal Sciences
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• v.9 no.5
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• pp.495-502
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• 1996

Much recent research on protein and amino acid (AA) digestive physiology of pigs has been concerned with measurement of the ileal apparent and true digestion and absorption. For measurement of the ileal apparent digestibility of AA, the steered ileo-caecal valve cannulation (SICV) and the ileo-rectal anastomosis (IRA) techniques appear to be the more reliable and simple methods, when compared with any methods requiring use of a marker for calculation of digestibility, or with the complex techniques of ileo-caecal re-entrant cannula (ICRC) and the postvalve ileo-colic re-entrant cannula (IPVC). On the other hand, the peptide alimentation ultrafiltration methods might be a better choice for measurement of the ileal endogenous nitrogen (N) and AA flow in a routine feedstuff analysis, although the classical method of $^{15}N-isotope$ dilution method is still a standard method for N and AA nutrition research in pigs.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.165-169
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• 2000

A simple method was suggested to calculate the stress intensity factor for a one-sided patched crack with finite thickness. To consider out-of-plane bending effect resulting from the load-path eccentricity, the spring constant as a function of the through-thickness coordinate z was calculated from the stress distribution in the un-cracked plate, ${\sigma}_{yy}(y=0,\;z)$, and the displacement for the representative single strip Joint, $u_y(y=0,\;z)$. The stress Intensity factors were obtained using Rose's asymptotic solution approach and compared with the finite element results. In short crack region, two results had a little difference. However, two results were almost same in long crack region. On the other hand, the stress intensity factor using plane stress assumption was more similar to finite element result than plane strain condition.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.13 no.5
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• pp.411-421
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• 1988

This paper offers a method to design CCD four-valued circuits using the tabular method. First, the four-valued logic function is decomposed by hand-calculation or computer program. Nest, the algorithm is derived form the tabular method based on the decomposition process to realize the DDC four-valued circuit. According to this algorithm, the two-variable four valued logic function is decomposed and realized by CCD network with four basic gates. The synthesis method in this paper proves that the number of devices and cost is considerably reduces as compared with the existing methods to realize the same logic functions.

• Journal of Power Electronics
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• v.13 no.4
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• pp.528-535
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• 2013

Most eco-friendly cars can adopt the concept of an integrated battery charger (IBC), which uses currently available motor drive systems. The IBC has a lot of strong points such as low cost and minimum space for the high voltage battery charger. On the other hand, it also has some defects caused by its structure. In this paper, the shortcomings of the conventional IBC for PHEVs with interior permanent magnet motors are discussed, and two advanced IBCs with improved performance are presented. Compared with the conventional IBC, the two advanced IBCs have plenty of strengths such as low common noise, high efficiency, simple sensing methods, etc. Then, the digital control algorithm is modified and a power loss calculation is carried out with simulation software. Finally, experimental results are provided to show the performance of the IBC systems.