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Wyszukujesz frazę "Shih, C." wg kryterium: Wszystkie pola


Wyświetlanie 1-3 z 3
Tytuł:
A new Early Cretaceous flea from China
Autorzy:
Zhang, Y.
Shih, C.
Rasnitsyn, A.P.
Ren, D.
Gao, T.
Powiązania:
https://bibliotekanauki.pl/articles/2082117.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Insecta
Siphonaptera
Saurophthiridae
Saurophthirus
ectoparasitic insects
compression fossils
Mesozoic
Asia
Opis:
Fleas are highly specialized holometabolic insects. So far, only 16 species of fossil fleas in five families have been reported due to the rare fossil records. At present, the earliest flea fossils are reported from the Middle Jurassic Jiulongshan Formation of Northeastern China. The descriptions of these earliest species pushed back the origin of Siphonaptera by at least 40 million years. It is generally accepted that saurophthirids are the “transitional” taxa from stem Jurassic fleas to living crown groups. Herein, we described a new “transitional” flea species, Saurophthirus laevigatus Zhang, Shih, Rasnitsyn, and Gao sp. nov., from the Lower Cretaceous Yixian Formation of Northeastern China, assigned to Saurophthiridae. The new species provides new evidence to support saurophthirids as a “transitional” group. Sexual dimorphism suggests significant differences in biology of opposite sexes in Saurophthirus. Analysis of described Mesozoic species demonstrates the body size reduction from the Middle Jurassic to the Early Cretaceous. Smaller body size was likely advantageous in reducing the probability of being detected and removed by the host and in minimizing flea’s demand for blood intake and energy input, indicating the adaptation of the ectoparasitic lifestyle of fleas in their early stage of evolution.
Źródło:
Acta Palaeontologica Polonica; 2020, 65, 1; 99-107
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new genus of lance lacewings from the Middle Jurassic of Inner Mongolia, China
Autorzy:
Ma, Y.
Shih, C.
Ren, D.
Wang, Y.
Powiązania:
https://bibliotekanauki.pl/articles/2082186.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Insecta
Neuroptera
Osmylidae
Osmylinae
Mesozoic
Asia
China
Opis:
Fossils of Osmylinae are rare, currently only one fossil genus of this subfamily is known, Lithosmylus which is recorded from the late Eocene Florissant Formation of USA. Herein, we report a new Osmylinae genus with two new species, Vetosmylus tentus gen. et sp. nov. and Vetosmylus maculosus gen. et sp. nov. from the Middle Jurassic Jiulongshan Formation of Daohugou Village, Inner Mongolia, China, The new genus shares many apomorphic characters with extant osmyline relatives, e.g., forked subcostal veinlets in forewing; dense cross-veins present in radial sector, usually forming one complete outer gradate series in forewing; the region between MA and MP significantly broadened in hind wing, but with only one row of cells, implying a likely morphological stasis during the evolution of Osmylinae. The new genus Vetosmylus, the first and earliest record hitherto of Osmylinae from the Mesozoic, enhances our understanding of the early stages of their evolution.
Źródło:
Acta Palaeontologica Polonica; 2020, 65, 2; 363-369
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of the Microstructure and Strengthening Mechanisms of Ti-6Cu-8Nb-xCr3C2 Alloy through Vacuum Sintering Process
Autorzy:
Chang, Shih-Hsien
Weng, Chen-Yu
Huang, Kuo-Tsung
Liang, Cheng
Powiązania:
https://bibliotekanauki.pl/articles/2106558.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
vacuum sintering
Ti-6Cu-8Nb-Cr3C2 alloy
hardness
transverse rupture strength
EBSD
Opis:
This study mixes four different powders to produce Ti-6Cu-8Nb-xCr3C2 (x = 1, 3, and 5 mass%) alloys in three different proportions. The experimental results reveal that when 5 mass% Cr3C2 was added to the Ti-6Cu-8Nb alloys, the specimen possessed optimal mechanical properties after sintering at 1275°C for 1 h. The relative density reached 98.23%, hardness was enhanced to 67.8 HRA, and the transverse rupture strength (TRS) increased to 1821.2 MPa, respectively. The EBSD results show that the added Cr3C2 in situ decomposed into TiC and NbC during the sintering process, and the generated intermetallic compounds (Ti2Cu) were evenly dispersed in the Ti matrix. Furthermore, the reduced Cr atom acts as a β-phase stabilizing element and solid-solution in the Ti matrix. Consequently, the main strengthening mechanisms of the Ti-6Cu-8Nb-xCr3C2 alloys include dispersion strengthening, solid-solution strengthening, and precipitation hardening.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 3; 815--825
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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