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        검색결과 13

        1.
        2023.10 구독 인증기관·개인회원 무료
        Necrophila (Calosilpha) brunnicollis brunnicollis (Kraatz, 1877) is a common necrophagous beetle in the Palaearctic region. The species is often encountered on the corpses of large vertebrates, such as human and pig, and is well recognized as a potentially group of beetles in forensic entomology. All of the developmental stages can be found in the corpse and under the soil near a corpse, which can be used to reconstruct the site, such as estimating PMI(Postmortem interval). However, its larval instar stages were never thoroughly described for identification. In this study, we redescribe the morphological characters of all larval stages of N. brunnicollis for quantitative and qualitative morphological information. In addition, we provide the images of larvae and an indentrifiaction key to larval instars.
        2.
        2023.10 구독 인증기관·개인회원 무료
        Callipogon relictus, a natural monument, is an insect whose life cycle was assumed to take more than 5 years in nature. Winter is a very harsh season, but it is known to be a crucial condition for many insects’ growth. However, no information is known about the overwintering condition and its effects on C. relictus. To understand the overwintering effects on the growth of C. relictus, we investigated the growth patterns of its larvae in indoor conditions after chilling treatment. The larvae were induced to dormancy at low temperature (4°C) for two months, and put them into 10°C for two weeks to break dormancy. After awakening, the temperature was increased 15°C, 20°C to 25°C at a time, and the larvae were kept for two weeks at each temperature. The larvae were divided into 3 groups (3rd to 5th instar, 6th to 8th instar, 9th to last instar). Lastly, head width and weight of the larvae were measured every 30 days under 25°C condition, and mortality and deformity were counted as well. The mortality and deformity rates were the highest in the first group, and the rates decreased toward the last group. On the other hands, growth rate appeared opposite to mortality and deformity rate of each larval group.
        11.
        2019.04 구독 인증기관·개인회원 무료
        The Australian genus Logasa Chandler was described in 2001 based on Logasa novaeangila Chandler 2001. Other two species, Logasa tricolor (Oke 1928) and Logasa ventralis (Oke 1928) were originally described as the genus Sagola, and transferred to Logasa by Chandler. During revisionary study using 140 museum specimens, additional three new species was recognized. After type examination of L. tricolor and L. ventralis, we found that they have different diagnostic characters for generic level such as foveal system and male genitalia. However, their diagnostic characters are not included any known faronite genus. Australian faronite fauna has numerous undescribed species. They will revise with other undescribed species for a following study.
        12.
        2016.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this study, six kinds of low-carbon steel specimens with different ferrite-pearlite microstructures were fabricated by varying the Nb content and the transformation temperature. The microstructural factors of ferrite grain size, pearlite fraction, interlamellar spacing, and cementite thickness were quantitatively measured based on optical and scanning electron micrographs; then, Charpy impact tests were conducted in order to investigate the correlation of the microstructural factors with the impact toughness and the ductile-brittle transition temperature (DBTT). The microstructural analysis results showed that the Nb4 specimens had ferrite grain size smaller than that of the Nb0 specimens due to the pinning effect resulting from the formation of carbonitrides. The pearlite interlamellar spacing and the cementite thickness also decreased as the transformation temperature decreased. The Charpy impact test results indicated that the impact-absorbed energy increased and the ductile-brittle transition temperature decreased with addition of Nb content and decreasing transformation temperature, although all specimens showed ductile-brittle transition behaviour.
        4,000원
        13.
        2015.08 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this study, low-carbon hypoeutectoid steels with different ferrite-pearlite microstructures were fabricated byvarying transformation temperature. The microstructural factors such as pearlite fraction and interlamellar spacing, and cementitethickness were quantitatively measured and then Charpy impact tests conducted on the specimens in order to investigate thecorrelation of the microstructural factors with impact toughness and ductile-brittle transition temperature. The microstructuralanalysis results showed that the pearlite interlamellar spacing and cementite thickness decreases while the pearlite fractionincreases as the transformation temperature decreases. Although the specimens with higher pearlite fractions have low absorbedenergy, on the other hand, the absorbed energy is higher in room temperature than in low temperature. The upper-shelf energyslightly increases with decreasing the pearlite interlamellar spacing. However, the ductile-brittle transition temperature is hardlyaffected by the pearlite interlamellar spacing because there is an optimum interlamellar spacing dependent on lamellar ferriteand cementite thickness and because the increase in pearlite fraction and the decrease in interlamellar spacing with decreasingtransformation temperature have a contradictory role on absorbed energy.
        4,000원