Long-wavelength(>500 km)magnetic anomalies originating in the lithosphere were first found in satellite magnetic surveys.Compared to the striking magnetic anomalies around the world,the long-wavelength magnetic ano...Long-wavelength(>500 km)magnetic anomalies originating in the lithosphere were first found in satellite magnetic surveys.Compared to the striking magnetic anomalies around the world,the long-wavelength magnetic anomalies in China and surrounding regions are relatively weak.Specialized research on each of these anomalies has been quite inadequate;their geological origins remain unclear,in particular their connection to tectonic activity in the Chinese and surrounding regions.We focus on six magnetic high anomalies over the(1)Tarim Basin,(2)Sichuan Basin(3)Great Xing’an Range,(4)Barmer Basin,(5)Central Myanmar Basin,and(6)Sunda and Banda Arcs,and a striking magnetic low anomaly along the southern part of the Himalayan-Tibetan Plateau.We have analyzed their geological origins by reviewing related research and by detailed comparison with geological results.The tectonic backgrounds for these anomalies belong to two cases:either ancient basin basement,or subduction-collision zone.However,the geological origins of large-scale regional magnetic anomalies are always subject to dispute,mainly because of limited surface exposure of sources,later tectonic destruction,and superposition of multi-phase events.展开更多
During the "14^(th) Five-Year Plan" period, consolidating the achievements of poverty alleviation, promoting rural revitalization and the high-quality development of farmers' cooperatives will overlap at...During the "14^(th) Five-Year Plan" period, consolidating the achievements of poverty alleviation, promoting rural revitalization and the high-quality development of farmers' cooperatives will overlap at the same time in the spatial field of ethnic minority areas, and they have consistency in content and commonality in value. The high-quality development of farmers' cooperatives in ethnic minority areas is an important organizational way to realize the modernization of agricultural industry, and it is also the key to consolidating the achievements of poverty alleviation and promoting rural revitalization at this stage. Because there is a gap between ethnic minority areas and developed areas in key factors of production such as capital, market, labor and technology, the development of farmers' cooperatives in ethnic minority areas faces more difficulties. This paper takes the development status and outstanding problems of farmers' cooperatives in Guizhou Province as the research object, discusses the connotation and significance of the high-quality development of farmers' cooperatives, and puts forward some strategies and suggestions on the governance of hollowing cooperatives, the allocation of key production factors, and the improvement of the quality of cooperatives.展开更多
Ce^(3+)as the active site on the CeO_(2)abrasive surface is the key to enhancing the material removal rate(MRR).The CeO_(2)abrasives with high chemical activity were prepared by the molten salt method under a reducing...Ce^(3+)as the active site on the CeO_(2)abrasive surface is the key to enhancing the material removal rate(MRR).The CeO_(2)abrasives with high chemical activity were prepared by the molten salt method under a reducing atmosphere.The crystal structure and morphology of CeO_(2)abrasive s were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),Fourier transform infrared spectroscopy(FT-IR),ultraviolet—visible diffuse reflectance spectroscopy(UV-Vis DRS),and X-ray photoelectron spectroscopy(XPS).The CeO_(2)abrasives were obtained under different atmospheres(Air,Ar,and Ar/H_(2)).With the enhancement of the reducing atmosphere,the morphology of the abrasives transforms from spherical to octahedral,while more oxygen vacancies and Ce^(3+)are generated on the surface of CeO_(2)abrasives.The CMP experiments show that the MRRs of the CeO_(2)-Air,CeO_(2)-Ar,and CeO_(2)-Ar/H_(2)abrasives on SiO_(2)substrates are 337.60,578.74,and 691.28 nm/min,respectively.Moreover,as confirmed by atomic force microscopy(AFM),the substrate surfaces exhibit low roughness(20.5 nm)after being polished using all of the prepared samples.Especially,the MRR of CeO_(2)-Ar/H_(2)abrasives is increased by 104.76%compared with CeO_(2)-air abrasives.The improved CMP performance is attributed to the increased Ce^(3+)concentration and the octahedral morphology of the abrasives enhancing the chemical reaction and mechanical removal at the abrasive-substrate interface.展开更多
We investigate the coherent control of spin tunneling for a spin–orbit(SO)coupled boson trapped in a driven triple well.In the high-frequency limit,the quasienergies of the system are obtained analytically and the fi...We investigate the coherent control of spin tunneling for a spin–orbit(SO)coupled boson trapped in a driven triple well.In the high-frequency limit,the quasienergies of the system are obtained analytically and the fine energy band structures are shown.By regulating the driving parameters,we reveal that the directed spin-flipping or spin-conserving tunneling of an SOcoupled boson occurs along different pathways and in different directions.The analytical results are demonstrated by numerical simulations and good agreements are found.Further,an interesting scheme of quantum spin tunneling switch with or without spin-flipping is presented.The results may have potential applications in the design of spintronic devices.展开更多
基金the National Natural Science Foundation of China(grant numbers 42004051,42274214,41904134).
文摘Long-wavelength(>500 km)magnetic anomalies originating in the lithosphere were first found in satellite magnetic surveys.Compared to the striking magnetic anomalies around the world,the long-wavelength magnetic anomalies in China and surrounding regions are relatively weak.Specialized research on each of these anomalies has been quite inadequate;their geological origins remain unclear,in particular their connection to tectonic activity in the Chinese and surrounding regions.We focus on six magnetic high anomalies over the(1)Tarim Basin,(2)Sichuan Basin(3)Great Xing’an Range,(4)Barmer Basin,(5)Central Myanmar Basin,and(6)Sunda and Banda Arcs,and a striking magnetic low anomaly along the southern part of the Himalayan-Tibetan Plateau.We have analyzed their geological origins by reviewing related research and by detailed comparison with geological results.The tectonic backgrounds for these anomalies belong to two cases:either ancient basin basement,or subduction-collision zone.However,the geological origins of large-scale regional magnetic anomalies are always subject to dispute,mainly because of limited surface exposure of sources,later tectonic destruction,and superposition of multi-phase events.
基金Supported by the Independent Research Project of PhD Candidate of Minzu University of China(BZKY2021073).
文摘During the "14^(th) Five-Year Plan" period, consolidating the achievements of poverty alleviation, promoting rural revitalization and the high-quality development of farmers' cooperatives will overlap at the same time in the spatial field of ethnic minority areas, and they have consistency in content and commonality in value. The high-quality development of farmers' cooperatives in ethnic minority areas is an important organizational way to realize the modernization of agricultural industry, and it is also the key to consolidating the achievements of poverty alleviation and promoting rural revitalization at this stage. Because there is a gap between ethnic minority areas and developed areas in key factors of production such as capital, market, labor and technology, the development of farmers' cooperatives in ethnic minority areas faces more difficulties. This paper takes the development status and outstanding problems of farmers' cooperatives in Guizhou Province as the research object, discusses the connotation and significance of the high-quality development of farmers' cooperatives, and puts forward some strategies and suggestions on the governance of hollowing cooperatives, the allocation of key production factors, and the improvement of the quality of cooperatives.
基金the National Natural Science Foundation of China(51905324)the Scientific Research Program Funded by Shaanxi Provincial Education Department(20JK0545)the Doctoral Scientific Research Startup Foundation of Shaanxi University of Science and Technology(2018BJ-14)。
文摘Ce^(3+)as the active site on the CeO_(2)abrasive surface is the key to enhancing the material removal rate(MRR).The CeO_(2)abrasives with high chemical activity were prepared by the molten salt method under a reducing atmosphere.The crystal structure and morphology of CeO_(2)abrasive s were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),Fourier transform infrared spectroscopy(FT-IR),ultraviolet—visible diffuse reflectance spectroscopy(UV-Vis DRS),and X-ray photoelectron spectroscopy(XPS).The CeO_(2)abrasives were obtained under different atmospheres(Air,Ar,and Ar/H_(2)).With the enhancement of the reducing atmosphere,the morphology of the abrasives transforms from spherical to octahedral,while more oxygen vacancies and Ce^(3+)are generated on the surface of CeO_(2)abrasives.The CMP experiments show that the MRRs of the CeO_(2)-Air,CeO_(2)-Ar,and CeO_(2)-Ar/H_(2)abrasives on SiO_(2)substrates are 337.60,578.74,and 691.28 nm/min,respectively.Moreover,as confirmed by atomic force microscopy(AFM),the substrate surfaces exhibit low roughness(20.5 nm)after being polished using all of the prepared samples.Especially,the MRR of CeO_(2)-Ar/H_(2)abrasives is increased by 104.76%compared with CeO_(2)-air abrasives.The improved CMP performance is attributed to the increased Ce^(3+)concentration and the octahedral morphology of the abrasives enhancing the chemical reaction and mechanical removal at the abrasive-substrate interface.
基金supported by the Scientific Research Foundation of Hunan Provincial Education Department under Grants No.21B0063 and No.18C0027the Hunan Provincial Natural Science Foundation of China under Grants No.2021JJ30435 and No.2017JJ3208the National Natural Science Foundation of China under Grant No.11747034。
文摘We investigate the coherent control of spin tunneling for a spin–orbit(SO)coupled boson trapped in a driven triple well.In the high-frequency limit,the quasienergies of the system are obtained analytically and the fine energy band structures are shown.By regulating the driving parameters,we reveal that the directed spin-flipping or spin-conserving tunneling of an SOcoupled boson occurs along different pathways and in different directions.The analytical results are demonstrated by numerical simulations and good agreements are found.Further,an interesting scheme of quantum spin tunneling switch with or without spin-flipping is presented.The results may have potential applications in the design of spintronic devices.
