Based on the digital observational data from pendulum tilt-meters and water tube tilt-meters, the spheroidal free oscillations of the Earth, excited by the M_S8.0 Wenchuan earthquake of May 12, 2008, were obtained usi...Based on the digital observational data from pendulum tilt-meters and water tube tilt-meters, the spheroidal free oscillations of the Earth, excited by the M_S8.0 Wenchuan earthquake of May 12, 2008, were obtained using the method of power spectral density estimation without any calculation to erase solid tides. The result matches well with the PREM results. Compared to the theoretical free oscillation from the PREM model, all relative errors are concentrated on 0.1% except for _0S_7, whose relative error is greater than 0.3%. This research provides a new method to determine the spheroidal modes of Earth's free oscillations from observations of the pendulum tilt-meter and water tube tilt-meter, which may be useful in the future study of the Earth's free oscillations.展开更多
The 0S2-0S54 spheroidal modes of Earth's free oscillations, triggered by the great Sumatra-Andaman earthquake of 26 December 2004 are retrieved from VHZ data recorded by seven upgraded stations of China Digital Seism...The 0S2-0S54 spheroidal modes of Earth's free oscillations, triggered by the great Sumatra-Andaman earthquake of 26 December 2004 are retrieved from VHZ data recorded by seven upgraded stations of China Digital Seismograph Network (CDSN). We compare these spheroidal modes with theoretical free oscillation spectra calculated from the Preliminary Reference Earth Model (PREM) and find a coincidence between their periods. Spectral splitting phenomenon is observed obviously in 0S2, 0S3, 0S4, 2S1 and 1S2 free oscillation modes. What is most noticeable is that the oscillation mode 2S1 is reported for the second time (the first time by Rosat et al) without any data stacking. We simulated the split singlet of 0S2 mode on seven CDSN stations based on general focal mechanism and seismic moment of the earthquake. The result shows that seismic moment of the earthquake can reach 10^23 N.m. We also find that the recording of Earth's free oscillations carries abundant information of source mechanism and earthquake location, which is applicable to the detailed study of source rupture parameters.展开更多
采用熔炼法制备出新型Ni Cu C固体自润滑材料,研究了稀土镁球化剂对Ni Cu C合金中石墨的球化作用。结果表明:在加入铜量0~50%范围内,用0.75%的稀土镁球化剂可以使结晶的石墨有效球化;石墨经球化处理后,形核密度提高,分布均匀;铜的固溶...采用熔炼法制备出新型Ni Cu C固体自润滑材料,研究了稀土镁球化剂对Ni Cu C合金中石墨的球化作用。结果表明:在加入铜量0~50%范围内,用0.75%的稀土镁球化剂可以使结晶的石墨有效球化;石墨经球化处理后,形核密度提高,分布均匀;铜的固溶作用提高了合金基体的硬度,增大了材料的电阻率,在加入量大的情况下,对石墨有一定的球化作用,但降低石墨的含量;Ni Cu C合金的自润滑性能随石墨含量的提高及球化而得到改善;与退火态45#钢和GCr15轴承钢进行干摩擦磨损时,Ni 20%Cu 3.5%C合金的摩擦因数分别保持在0.12和0.13。展开更多
文摘Based on the digital observational data from pendulum tilt-meters and water tube tilt-meters, the spheroidal free oscillations of the Earth, excited by the M_S8.0 Wenchuan earthquake of May 12, 2008, were obtained using the method of power spectral density estimation without any calculation to erase solid tides. The result matches well with the PREM results. Compared to the theoretical free oscillation from the PREM model, all relative errors are concentrated on 0.1% except for _0S_7, whose relative error is greater than 0.3%. This research provides a new method to determine the spheroidal modes of Earth's free oscillations from observations of the pendulum tilt-meter and water tube tilt-meter, which may be useful in the future study of the Earth's free oscillations.
基金State Key Fundamental Research Development Plan Project (2001CB711005) National Natural Science Founda-tion of China (40374012)
文摘The 0S2-0S54 spheroidal modes of Earth's free oscillations, triggered by the great Sumatra-Andaman earthquake of 26 December 2004 are retrieved from VHZ data recorded by seven upgraded stations of China Digital Seismograph Network (CDSN). We compare these spheroidal modes with theoretical free oscillation spectra calculated from the Preliminary Reference Earth Model (PREM) and find a coincidence between their periods. Spectral splitting phenomenon is observed obviously in 0S2, 0S3, 0S4, 2S1 and 1S2 free oscillation modes. What is most noticeable is that the oscillation mode 2S1 is reported for the second time (the first time by Rosat et al) without any data stacking. We simulated the split singlet of 0S2 mode on seven CDSN stations based on general focal mechanism and seismic moment of the earthquake. The result shows that seismic moment of the earthquake can reach 10^23 N.m. We also find that the recording of Earth's free oscillations carries abundant information of source mechanism and earthquake location, which is applicable to the detailed study of source rupture parameters.
文摘采用熔炼法制备出新型Ni Cu C固体自润滑材料,研究了稀土镁球化剂对Ni Cu C合金中石墨的球化作用。结果表明:在加入铜量0~50%范围内,用0.75%的稀土镁球化剂可以使结晶的石墨有效球化;石墨经球化处理后,形核密度提高,分布均匀;铜的固溶作用提高了合金基体的硬度,增大了材料的电阻率,在加入量大的情况下,对石墨有一定的球化作用,但降低石墨的含量;Ni Cu C合金的自润滑性能随石墨含量的提高及球化而得到改善;与退火态45#钢和GCr15轴承钢进行干摩擦磨损时,Ni 20%Cu 3.5%C合金的摩擦因数分别保持在0.12和0.13。
基金The National Natural Science Foundation of China(No.51301038,51201031,51371050)the Industry-AcademiaResearch Cooperative Innovation Fund of Jiangsu Province(No.BY2014127-03)+1 种基金the Natural Science Foundation of Jiangsu Province(No.BK20141306)the Scientific and Technological Innovation Fund of Danyang(No.SY201305)