• Smart Structures and Systems
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• v.10 no.1
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• pp.67-87
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• 2012

A dragonfly inspired flapping wing is investigated in this paper. The flapping wing is actuated from the root by a PZT-5H and PZN-7%PT single crystal unimorph in the piezofan configuration. The non-linear governing equations of motion of the smart flapping wing are obtained using the Hamilton's principle. These equations are then discretized using the Galerkin method and solved using the method of multiple scales. Dynamic characteristics of smart flapping wings having the same size as the actual wings of three different dragonfly species Aeshna Multicolor, Anax Parthenope Julius and Sympetrum Frequens are analyzed using numerical simulations. An unsteady aerodynamic model is used to obtain the aerodynamic forces. Finally, a comparative study of performances of three piezoelectrically actuated flapping wings is performed. The numerical results in this paper show that use of PZN-7%PT single crystal piezoceramic can lead to considerable amount of wing weight reduction and increase of lift and thrust force compared to PZT-5H material. It is also shown that dragonfly inspired smart flapping wings actuated by single crystal piezoceramic are a viable contender for insect scale flapping wing micro air vehicles.

• Korean Journal of Environment and Ecology
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• v.27 no.2
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• pp.209-218
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• 2013

This study was conducted to analyze the characteristics of odonata communities as habitat types in Wonju City, Korea. The 33 plots were installed at 4 types of biotope like abandoned paddy fields, natural type reservoir, natural type river and forest valley in Wonju city. From the survey, the 9 family and 38 species were identified. As the result of comparative investigation of the species composition of each habitat through TWINSPAN analyzing, the difference of species composition was definite in abandoned paddy field, natural type reservoir and forest valley, however, it was uncertain in natural type river. The dominant species and the subdominant species of each habitat were mainly Sympetrum frequens and Sympetrum infuscatum but the distributions of Paracercion hieroglyphicum, Epophthalmia elegans, and Anax parthenope julius were different as haibtat types. The order of the index of species diversity was not different between abandoned paddy fiedls, natural type reservoir and natural type river, but forest valley was low. The abandoned paddy field was shown the most diverse spawning type of odonata, it is considered that hydrophyten play an important role in the abundant of odonata since the sorts of odonata spawning in plants are majority. As the result of analyzing interspecies relationship, Crocothemis servilia mariannae and Orthetrum albistylum, Crocothemis servilia mariannae-Platycnemis phyllopoda, Lyriothemis pachygastra-Sympetrum parvulum are shown the positive correlation, however, they have a difference in preferred habitat between high correlation species.

• Journal of Life Science
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• v.18 no.3
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• pp.363-368
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• 2008

The in vitro thrombin inhibitory activities of 304 crude extracts from 76 kinds of korean wild insects were evaluated. Measurement of thrombin time showed that the DMSO extracts of Acrida cinerea cinerea (Thunberg), Anax parthenope julius Brauer, Eurydema rugosa Motschulsky, and Stethophyma magister (Rehn) and the water extracts of Dolycoris baccarum Linne, Lixus divaricatus Motschulsky, Metrioptera bonneti, Moechotypa diphysis (Pascoe), Nicrophorus concolor sp., and Tomapoderus ruficollis (Fabricius) had strong thrombin inhibitory activity. No prominent changes of activated partial thromboplastin time by treatment of the selected extracts suggested direct inhibition of thrombin activity by the insect extracts. DPPH scavenging activity of selected extracts showed that the extract of A. cinerea cinerea (Thunberg), D. baccarum Linne, L. divaricatus Motschulsky and N. concolor sp. has good antioxidant activity as well as antithombin activity. Our results suggested that some of korean wild insects could be developed as a natural source of antithrombosis.