• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.12
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• pp.22-27
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• 2019

In this study, the flow rate and air resistance pressure were analyzed on models a, b, and c due to the front wing angle of the airplanes. Models a, b, and c have front wing angles of 120°, 100°, and 160°, respectively. The results of the flow analyses showed that the flow rate and air resistance pressure of model c were observed to be higher than models a and b. The airplane model with a larger angle to the front wing is thought to be the best model for flight. This result can be applied to development of the best in-flight airplane.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.11
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• pp.709-717
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• 2017

In this study, a model of two-stage Weis-Fogh type water turbine model is proposed, the hydrodynamic characteristics of this water turbine model are calculated by the advanced vortex method. The basic conditions and the motion of each wing are the same as that of the single-stage model previously proposed by the same author. The two wings (NACA0010 airfoils) and both channel walls are approximated by source and vortex panels, and free vortices are introduced from the body surfaces. The distance between the front wing axis and the rear wing axis, and the phase difference between the motion of the two wings, which is in phase and out of phase are set as the calculation parameters. For each case, the unsteady flow fields, pressure fields, force coefficients, and efficiency of the two wings are calculated, and the hydrodynamic characteristics of the proposed water turbine model are discussed.

• Korean journal of applied entomology
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• v.29 no.1
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• pp.1-5
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• 1990

A morphological study on the immature and adult stages of Anagrus incarnatus Haliday was carried out under laboratory condition at 25$\pm$1$^{\circ}C$. The egg is sausage-shaped with a long slender pedicel. The first instar is a bag-shaped larva. The second instar larval form of A. incarnatus is similar to he "histriobdellid" stage. The antenna has 9 and 13 segments of the female and male, respectively. The first funicular segment of the female's antenna is very short, subspherical or globular type and the third funicular segment with one sensory ridge is longer than the forth. The forewing of A. incarnatus has 8-9 rows of discal hairs providing no bare space at the broadest part. The length of ovarian eggs, egg, 1st instar, and 2nd instar of A. incarnatus is 0.165, 0.215, 0.290, and 0.535 mm, respectively, and the width of each stages is 0.025, 0.057, 0.082, and 0.110 mm, respectively. The developmental periods for egg, 1st instar, 2nd instar, prepupa, and pupal stage are about 1, 1, 4, 1, 5-6 days, respectively.pectively.