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Jiaxing Shen,Zihao Pan,Ping Xu,Yinghua Yu 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.7
The thermal performance of a steel-basalt fiber polymer concrete machine tool joint surface has a key influence on a machine tool. Based on virtual material theory, the equivalent thermal model was established and the thermal performance parameters of virtual materials were deduced by theoretical calculation. The calculation method of actual contact area ratio of steel - basalt fiber polymer concrete joint surface was established based on discrete principle and its accuracy was verified. To determine the influence of preload pressure on the actual contact area ratio, a prediction model was established. The thermal conductivity of the material was measured by the quasi-steady state method. A new systematic simulation analysis method that synthesizes virtual material theory and finite element simulation analysis was proposed, and its accuracy was verified. The results show that the relative error is only 5.01 %, which proves the method’s effectiveness.
Ma Weihua,Long Denglong,Wang Yi,Li Xinyu,Huang Jiaxing,Shen Jinshan,Su Wenting,Jiang Yusuo,Li Jie 한국응용곤충학회 2021 Journal of Asia-Pacific Entomology Vol.24 No.1
Honeybee pollination behavior is influenced by flower volatiles, which honeybees sense via olfactory receptors. Honeybees are only weakly attracted to pear flowers. To investigate the potential reasons, we extracted and determined the floral volatile compounds from three pear cultivars (Su, Ya, and Xuehua) using headspace solidphase micro-extraction (HS-SPME) and gas chromatography-mass spectrometry (GC–MS). The effects of pear flower volatiles on the Asian honeybee (Apis cerana cerana Fabricius) and the European honeybee (Apis mellifera ligustica Spinola) were determined by electroantennogram (EAG) assays and behavioral tests in a three-arm olfactometer. Among the 76 flower volatiles detected with GC–MS, 21 were found in all three pear cultivars, accounting for approximately 70% of the total volatile content. 3-Methyl-1-butanol and (+)-limonene volatiles had the highest relative content. Five compounds elicited strong EAG responses in both bee species: 2-methylbu tyraldehyde, 1-nonanal, 6-methyl-5-hepten-2-one, 3-methyl-1-butanol, and (+)-limonene. Neither bee species showed positive taxis to these volatiles. In behavioral tests, A. mellifera ligustica showed a low preference for 6-methyl-5-hepten-2-one (20%, 400 µg/µL) and 2-phenethyl alcohol (16.7%, 400 µg/µL). Apis cerana cerana showed a low preference for 6-methyl-5-hepten-2-one (6.7%, 400 µg/µL) and 1-nonanal (10%, 400 µg/µL), whereas its preferences for 3-methyl-1-butanol (43.3%, 400 µg/µL) and α-farnesene (40%, 400 µg/µL) were similar to that for the control. Therefore, a lack of attractive volatile compounds could explain why honeybees are only weakly attracted to pear flowers. Therefore, to achieve acceptable pollination in pear orchards, we suggest using flower-scent sugar syrup feeding and a saturation pollination strategy.