• 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.37 no.1
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• pp.39-48
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• 1998

To know whether there is any androconia on Korean Lycaenidae, studies were carried out with Korean Lycaenid butterflies for their types and distribution pattern with the aid of scanning electron microscope. As the results, androconia was observed from 8 species; Niphanda fusca (B. et G.), Pseudozizeeria maha (K.), Zizina otis (F.), Everes argiades (P.), Celasrtina argiolus (L.), Maculinea arionides (S.), M. teleius (B.) and Lycaeides argyronomon (B.). Androconia was not found only from males, and it was observed on both dorsal and ventral surfaces of fore wings and on ventral surface of hind wings. Androconia was found to be distributed mainly on the area between the median and anal venis. General structure of androconia on Korean Lycaenids was rather simple with laminar and foot stalk. However, 2 types of androconia were observed from 2 species, Pseudozizeeria maha and Everes argiades, while only one type was observed from other 6 species. The foot stalks of androconia on Niphanda fusca under the tribe Niphandini is located on the ventral surface of laminar and hidden from dorsal view, while one end of that on all other 7 species belong to the tribe Polyommatini is attached to the lower side of laminar and shown from both side.

• Korean journal of applied entomology
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• v.55 no.1
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• pp.67-71
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• 2016

Chiasmia cinerearia (Bremer et Grey) belonging to the subfamily Ennominae(Lepidoptera: Geometridae) is a new forestry pest attacking to Sophora japonica in Gyeonggi province. Chiasmia cinerearia oviposited about 250~300 eggs per female on leaves. Larva had five instar stages. Adults emerged twice a year in early May and late July. The period of one generation was about 48 days. Body length of larvae was 25~30 mm and body color was light green with dark yellow lateral lines in abdomen. The wingspan of adults was 30 to 35 mm in length. The color of forewings was greyish brown with quadrilateral patterns on outer lines.

• 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.

• Korean Journal of Ecology and Environment
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• v.36 no.4 s.105
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• pp.427-433
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• 2003

We provided diagnostic characters of the adult and larval stages of two co-inhabiting species of ephemerid burrowing mayflies, Ephemera orientalis and E. sachalinensis (new record to South Korea) (Ephemeroptera: Ephemeridae), in Korean streams. E. sachalinensis (mean${\pm}$sd body length male adult 18.44${\pm}$0.70 mm, female adult 21.46${\pm}$0.45 mm) is larger in body length than E. orientalis (male adult 13.92${\pm}$0.04 mm, female adult 15.27 ${\pm}$ 0.48 mm), and can be distinguished by male genitalia, forewing markings, and stripes on the abdominal terga Vl-lX. The mature larvae of E. sachalinensis differ from those of E. orientalis in having a deeper and more divergent head frontal process. Their body size distributions and additional ecolegical findings are discussed.

• Korean journal of applied entomology
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• v.47 no.2
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• pp.111-115
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• 2008

This study was conducted to distinguish adult morphology of the giant water bug (Lethocerus deyrollei) between over-wintered (OLD) and new-born (NEW) populations using materials collected from Gyodong island in Gyeonggi-do, Korea, as well as individuals reared in the laboratory (LAB population) as a control. As a result, no fundamental differences were found in external body structure between OLD, NEW, and LAB populations. However, marginal area of basal procoxa in ventral prothorax and jointed part of forefemur and foretibia were greatly worn in the OLD population. Mid-claws were shorter than 0.5 times the length of the 2nd mid-tarsus; the membranous margin of hemelytra was greatly worn; and hairs of the 5th abdominal tergum were greatly reduced in the OLD population.

• Korean journal of applied entomology
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• v.61 no.3
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• pp.399-408
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• 2022

There has been much debate on the morphometric divergence between the recently identified Apis cerana koreana and Apis cerana honey bees. The aim of this study was to obtain phenotypic information that can be used to compare A. c. koreana data with other A. cerana subspecies data from open resources and determine breeding results on the basis of morphometric traits. To differentiate A. c. koreana, we investigated 22 classic morphological characteristics; royal jelly secretion; and the weight of workers, queens, and drones of A. c. koreana bred in Korea. To define the selection results, we used the geometric morphometric method. The artificially selected A. c. koreana secreted significantly more royal jelly (1.18 times) than the naturally selected A. c. koreana, which positively influenced the health of the colonies. These honey bees were identified more clearly with the geometric morphometric method than with the classic morphometric method, which is traditionally used to determine the subspecies. Large trends were noted for A. c. koreana on the basis of our results and literature from the 1980s regarding A. cerana sizes in Korea (tarsal index, length of forewing, and cubital index were measured). The cluster analysis revealed the proximity of A. c. koreana, A. cerana in China, and A. c. indica on the basis of eight classic characters, which, perhaps, relay the origin of the honey bees. The results of this study defined the morphometric responses of A. c. koreana honey bees to geographic isolation, climate change, and selection, which are important to identify, protect, and preserve honey bee stock in Korea.

• Korean journal of applied entomology
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• v.48 no.1
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• pp.53-57
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• 2009

Biological Characteristics of Lycorma delicatula and insecticidal activity of some insecticides against nymphs of L. delicatula was investigated. Nymph of L. delicatula had 4 instars, and color of body was black. There were white spots on the body of 1st-3rd nymph. Upper body became red at 4th nymph. Adult forewings were brownish, and had black spots. Color of hind wing were red. The egg mass was covered with a yellowish brown secretion. The adult of L. delicatula emerged once a year. Among test insecticides, deltamethrin 1% EC and fenitrothion 50% EC showed very quick and strong insecticidal activity against the 2nd-3rd nymphs of L. delicatula. Imidacloprid 4% SL and clothianidin 8% SC showed 100% insecticidal activity at 24h after treatment. Thiacoprid 10% SC revealed the weakest insecticidal activity among the insecticides tested.

• Korean journal of applied entomology
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• v.52 no.4
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• pp.265-271
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• 2013

Morphometric analysis of Lycorma delicatula was performed to confirm whether local individuals had a geographical difference in their wing variations. The L. delicatula individuals were collected from 10 localities in Korea, China, and Japan, and 14 morphometric characteristics selected from the forewing were analyzed. The Korean individuals were similar to the ones from the northern area of the Yangtze River, but less similar to the others from the southern area of the Yangtze River. The individuals from Seoul and Buan were very similar to those from Shanghai. In case of wing spots, the individuals from Beijing had relatively small spots, while the ones from Linan had big spots. The Japanese individuals had a relatively large wing size.

• Journal of the Society of Naval Architects of Korea
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• v.39 no.3
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• pp.8-17
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• 2002

In this paper, the computational analysis of open-water characteristics for three model propellers(P4119, P4842 and 3 podded propeller of KRISO) is done by using a viscous-flow method based on Reynolds-Averaged Navier-Stokes equations. The results are presented for open-water performances, blade-section pressures, and circumferentially-averaged velocity profiles for the all three propeller models. Overall close agreements with available experimental data are shown. However, some discrepancies are also found in the pressure near the leading edge of the propeller blade and the open-water performance of the podded propellers.