Two eruption episodes are identified through systematic field investigations and K-Ar dating of the late Mesozoic volcanic rocks in the North Huaiyang belt (NHB), Dabie orogenic belt, of which the earlier volcanic sui...Two eruption episodes are identified through systematic field investigations and K-Ar dating of the late Mesozoic volcanic rocks in the North Huaiyang belt (NHB), Dabie orogenic belt, of which the earlier volcanic suite termed Maotanchang Fm. (Fm.) occurring at Jinzhai, Xianhualing and Maotanchang, etc., was erupted from 149 Ma to 138 Ma. The other named Xiaotian Fm. mainly distributed at Xiaotian, Shucheng, etc., was formed between 132 Ma and 116 Ma. During the eruption gap of the two volcanic suites deposited a volcano-sedimentary conglomerate layer, which are composed of the multi-compositional gravels, including the North Dabie orthogneiss complex (NDOC), volcanic gravels, etc. These volcanic gravels in the conglomerate layer show identical geochemical and isotopic compositions (87Sr/86Sr(t) =0.7084-0.7092,εNd(t) =-21.8--24.4) to the Maotanchang Fm. volcanic rocks (87Sr/86Sr = 0.7086-0.7102,εNd = -19.2-24.4), but significantly distinct from those of Xiaotian Fm. (87Sr/86Sr = 0.7076-0.7084, εNd=展开更多
为提高油浸式电力变压器故障状态评估的准确性,结合局部密度聚类(local density clustering,LDC)算法和三比值法提出一种变压器故障状态评估方法——以油中溶解气体为研究对象,对气体数据进行LDC处理,以最后聚类结果作为故障状态评估模...为提高油浸式电力变压器故障状态评估的准确性,结合局部密度聚类(local density clustering,LDC)算法和三比值法提出一种变压器故障状态评估方法——以油中溶解气体为研究对象,对气体数据进行LDC处理,以最后聚类结果作为故障状态评估模型及结合三比值法对新数据进行故障评估。该方法在弥补聚类方法无法准确反映故障状态和三比值法编码不全、编码太片面等不足的同时,在变压器状态发生变化时能随着新数据的输入自主修正故障状态评估模型。不同实验结果表明该方法用在变压器故障评估中,具有较高的故障评估准确率,并且当出现未知故障时能有效修正所搭建故障状态评估模型,可以在一定程度上反映变压器故障状态,保证变压器正常、安全运行。展开更多
Mesozoic and Cenozoic basalitc rnagmatism within the basins around Bohai area displays temporal variations in petrochemistry,trace element and isotope geochmistry. Two stages of evolution are recognized. The preextens...Mesozoic and Cenozoic basalitc rnagmatism within the basins around Bohai area displays temporal variations in petrochemistry,trace element and isotope geochmistry. Two stages of evolution are recognized. The preextension magmatism (134 - 91 Ma,Jiyang basin) is characterised by small volumes of alkaline basalts and potassic lamprophyres. These rocks are interpreted as results of very small degrees of partial melting of the lithosphere and volatile-rich metasome within the lithosphere induced by initial thermal perturbation. The second stage (74- 27 Ma) coincides with the lithospheric extension. It, is noted that the alkalinity and Dea of basalts increased systematically from 74 to 27 Ma. Major element chemistry,trace element modelling antl experimental data indicate that there is an increase in depth of melting and a decrease in degree of partial melting from 74 to 27 Ma. Such a temporal change in source character and in the depth of origin is best understood when magmatism is considered within the framework of a lithosphere-asthenos phere interaction model where melting is initiated by discrete thermal events related lithospheric extension.展开更多
The Circular Electron Positron Collider(CEPC)is a large scientific project initiated and hosted by China,fostered through extensive collaboration with international partners.The complex comprises four accelerators:a 3...The Circular Electron Positron Collider(CEPC)is a large scientific project initiated and hosted by China,fostered through extensive collaboration with international partners.The complex comprises four accelerators:a 30 GeV Linac,a 1.1 GeV Damping Ring,a Booster capable of achieving energies up to 180 GeV,and a Collider operating at varying energy modes(Z,W,H,and tt).The Linac and Damping Ring are situated on the surface,while the subterranean Booster and Collider are housed in a 100 km circumference underground tunnel,strategically accommodating future expansion with provisions for a potential Super Proton Proton Collider(SPPC).The CEPC primarily serves as a Higgs factory.In its baseline design with synchrotron radiation(SR)power of 30 MW per beam,it can achieve a luminosity of 5×10^(34)cm^(-2)s^(-1)per interaction point(IP),resulting in an integrated luminosity of 13 ab^(-1)for two IPs over a decade,producing 2.6 million Higgs bosons.Increasing the SR power to 50 MW per beam expands the CEPC's capability to generate 4.3 million Higgs bosons,facilitating precise measurements of Higgs coupling at sub-percent levels,exceeding the precision expected from the HL-LHC by an order of magnitude.This Technical Design Report(TDR)follows the Preliminary Conceptual Design Report(Pre-CDR,2015)and the Conceptual Design Report(CDR,2018),comprehensively detailing the machine's layout,performance metrics,physical design and analysis,technical systems design,R&D and prototyping efforts,and associated civil engineering aspects.Additionally,it includes a cost estimate and a preliminary construction timeline,establishing a framework for forthcoming engineering design phase and site selection procedures.Construction is anticipated to begin around 2027-2028,pending government approval,with an estimated duration of 8 years.The commencement of experiments and data collection could potentially be initiated in the mid-2030s.展开更多
The effective elastic thickness （Te） represents the thickness of the elastic layer or the flexural rigidity of the lithosphere, the equivalent of which can be calculated from the spectral analysis of gravity and top...The effective elastic thickness （Te） represents the thickness of the elastic layer or the flexural rigidity of the lithosphere, the equivalent of which can be calculated from the spectral analysis of gravity and topographic data. Studies of Te have profound influence on intracontinental deformation, and coupling of the tectonic blocks. In this paper, we use the multitaper spectral estimation method to calculate the coherence between Bouguer gravity and topography data, and to obtain the Te map of South China. Through the process of correction, we discuss the relationships of Te versus heat flow, and Te versus seismicity. The results show that Te distribution of South China is affected by three factors：the original age, which controls the basic feature;the Mesozoic evolution, which affects the Te distribution;and the neotectonic movement, which shaped the final distribution. The crust age has a positive correlation with the first-order Te distribution;thus the Yangtze Craton has a relatively higher Te （about 50 km） whereas the Te in Cathaysia block is only 10e20 km. By analysis and comparison among the tectonic models of South China, the Te distribution can be well explained using the flat-subduction model. As is typical with neotectonics, the region with a higher heat flow is related with a lower Te. The seismicity does not have a clear relationship with Te, but the strong seismicity could cause a low Te. Seismogenic layer （Ts） has a similar trend as Te in the craton, whereas in other areas the relationship is complex.展开更多
基金This work was jointly supported bythe National Natural Science Foundation of China (Grant Nos. 49873011 and 40073011) the Chinese Ministry of Science and Technology (Grant Nos. G1999075504 and G1999043302).
文摘Two eruption episodes are identified through systematic field investigations and K-Ar dating of the late Mesozoic volcanic rocks in the North Huaiyang belt (NHB), Dabie orogenic belt, of which the earlier volcanic suite termed Maotanchang Fm. (Fm.) occurring at Jinzhai, Xianhualing and Maotanchang, etc., was erupted from 149 Ma to 138 Ma. The other named Xiaotian Fm. mainly distributed at Xiaotian, Shucheng, etc., was formed between 132 Ma and 116 Ma. During the eruption gap of the two volcanic suites deposited a volcano-sedimentary conglomerate layer, which are composed of the multi-compositional gravels, including the North Dabie orthogneiss complex (NDOC), volcanic gravels, etc. These volcanic gravels in the conglomerate layer show identical geochemical and isotopic compositions (87Sr/86Sr(t) =0.7084-0.7092,εNd(t) =-21.8--24.4) to the Maotanchang Fm. volcanic rocks (87Sr/86Sr = 0.7086-0.7102,εNd = -19.2-24.4), but significantly distinct from those of Xiaotian Fm. (87Sr/86Sr = 0.7076-0.7084, εNd=
文摘为提高油浸式电力变压器故障状态评估的准确性,结合局部密度聚类(local density clustering,LDC)算法和三比值法提出一种变压器故障状态评估方法——以油中溶解气体为研究对象,对气体数据进行LDC处理,以最后聚类结果作为故障状态评估模型及结合三比值法对新数据进行故障评估。该方法在弥补聚类方法无法准确反映故障状态和三比值法编码不全、编码太片面等不足的同时,在变压器状态发生变化时能随着新数据的输入自主修正故障状态评估模型。不同实验结果表明该方法用在变压器故障评估中,具有较高的故障评估准确率,并且当出现未知故障时能有效修正所搭建故障状态评估模型,可以在一定程度上反映变压器故障状态,保证变压器正常、安全运行。
文摘Mesozoic and Cenozoic basalitc rnagmatism within the basins around Bohai area displays temporal variations in petrochemistry,trace element and isotope geochmistry. Two stages of evolution are recognized. The preextension magmatism (134 - 91 Ma,Jiyang basin) is characterised by small volumes of alkaline basalts and potassic lamprophyres. These rocks are interpreted as results of very small degrees of partial melting of the lithosphere and volatile-rich metasome within the lithosphere induced by initial thermal perturbation. The second stage (74- 27 Ma) coincides with the lithospheric extension. It, is noted that the alkalinity and Dea of basalts increased systematically from 74 to 27 Ma. Major element chemistry,trace element modelling antl experimental data indicate that there is an increase in depth of melting and a decrease in degree of partial melting from 74 to 27 Ma. Such a temporal change in source character and in the depth of origin is best understood when magmatism is considered within the framework of a lithosphere-asthenos phere interaction model where melting is initiated by discrete thermal events related lithospheric extension.
基金support from diverse funding sources,including the National Key Program for S&T Research and Development of the Ministry of Science and Technology(MOST),Yifang Wang's Science Studio of the Ten Thousand Talents Project,the CAS Key Foreign Cooperation Grant,the National Natural Science Foundation of China(NSFC)Beijing Municipal Science&Technology Commission,the CAS Focused Science Grant,the IHEP Innovation Grant,the CAS Lead Special Training Programthe CAS Center for Excellence in Particle Physics,the CAS International Partnership Program,and the CAS/SAFEA International Partnership Program for Creative Research Teams.
文摘The Circular Electron Positron Collider(CEPC)is a large scientific project initiated and hosted by China,fostered through extensive collaboration with international partners.The complex comprises four accelerators:a 30 GeV Linac,a 1.1 GeV Damping Ring,a Booster capable of achieving energies up to 180 GeV,and a Collider operating at varying energy modes(Z,W,H,and tt).The Linac and Damping Ring are situated on the surface,while the subterranean Booster and Collider are housed in a 100 km circumference underground tunnel,strategically accommodating future expansion with provisions for a potential Super Proton Proton Collider(SPPC).The CEPC primarily serves as a Higgs factory.In its baseline design with synchrotron radiation(SR)power of 30 MW per beam,it can achieve a luminosity of 5×10^(34)cm^(-2)s^(-1)per interaction point(IP),resulting in an integrated luminosity of 13 ab^(-1)for two IPs over a decade,producing 2.6 million Higgs bosons.Increasing the SR power to 50 MW per beam expands the CEPC's capability to generate 4.3 million Higgs bosons,facilitating precise measurements of Higgs coupling at sub-percent levels,exceeding the precision expected from the HL-LHC by an order of magnitude.This Technical Design Report(TDR)follows the Preliminary Conceptual Design Report(Pre-CDR,2015)and the Conceptual Design Report(CDR,2018),comprehensively detailing the machine's layout,performance metrics,physical design and analysis,technical systems design,R&D and prototyping efforts,and associated civil engineering aspects.Additionally,it includes a cost estimate and a preliminary construction timeline,establishing a framework for forthcoming engineering design phase and site selection procedures.Construction is anticipated to begin around 2027-2028,pending government approval,with an estimated duration of 8 years.The commencement of experiments and data collection could potentially be initiated in the mid-2030s.
基金supported financially by the Ministry of Science and Technology of China (Sinoprobe-03-02)the National Natural Science Foundation of China (Grant No. 41021063)
文摘The effective elastic thickness （Te） represents the thickness of the elastic layer or the flexural rigidity of the lithosphere, the equivalent of which can be calculated from the spectral analysis of gravity and topographic data. Studies of Te have profound influence on intracontinental deformation, and coupling of the tectonic blocks. In this paper, we use the multitaper spectral estimation method to calculate the coherence between Bouguer gravity and topography data, and to obtain the Te map of South China. Through the process of correction, we discuss the relationships of Te versus heat flow, and Te versus seismicity. The results show that Te distribution of South China is affected by three factors：the original age, which controls the basic feature;the Mesozoic evolution, which affects the Te distribution;and the neotectonic movement, which shaped the final distribution. The crust age has a positive correlation with the first-order Te distribution;thus the Yangtze Craton has a relatively higher Te （about 50 km） whereas the Te in Cathaysia block is only 10e20 km. By analysis and comparison among the tectonic models of South China, the Te distribution can be well explained using the flat-subduction model. As is typical with neotectonics, the region with a higher heat flow is related with a lower Te. The seismicity does not have a clear relationship with Te, but the strong seismicity could cause a low Te. Seismogenic layer （Ts） has a similar trend as Te in the craton, whereas in other areas the relationship is complex.
