Investigating the formation mechanisms of carbonate geothermal reservoirs is of theoretical and practical significance for summarizing the formation pattern of geothermal resources and further guiding their effective ...Investigating the formation mechanisms of carbonate geothermal reservoirs is of theoretical and practical significance for summarizing the formation pattern of geothermal resources and further guiding their effective exploitation.The Beijing-Tianjin-Hebei Plain(BTHP),predominantly located within the Jizhong Depression and Cangxian Uplift in the Bohai Bay Basin,serves as the primary region for geothermal exploitation and utilization in China.More than 1500 geothermal wells have been drilled therein,with water temperature at the wellhead ranging from 55 to 110°C,single-well flow rate ranging between 80 and 120 m^(3)/h,and cumulative heating area exceeding 100×10^(6)m^(3).However,the exploration and research in the region remain limited overall.As per the previous geothermal and petroleum exploration results and the latest geothermal drilling data,this study comprehensively evaluated the geothermal resources of karst geothermal reservoirs.The results show that two suites of carbonate karst reservoirs,namely the Jxw Formation and the Ordovician strata,have primarily developed in the BTHP,and their formation and evolution can be divided into four stages:the Mesoproterozoic-Early Paleozoic stage with carbonate sedimentation and the development of interlayer karst,the Late Paleozoic stage with the development of direct sedimentary cover,the Mesozoic stage with compressional uplifting and development of buried hill karst,and the Cenozoic stage with regional cover deposition and the modification and finalization of karst geothermal reservoirs.Accordingly,the porosity evolution history of the geothermal reservoirs is composed of three stages,namely a significant decrease followed by a minor increase,a gradual decline,and then a small fluctuation from increase to decrease before slowly rising again.The karstification in geothermal reservoirs can be summarized into quasi-syngenetic karstification,epigenetic karstification,and burial karstification,which can be subdivided into seven subcategories.The carbonate geothermal reservoirs in the study area boast total geothermal resources of 53.821×10^(9)GJ,or 184.155×10^(9)t of standard coal equivalent(tce),and the annual exploitable geothermal resources in the urban area can heat an area of(400‒500)×10^(6)m^(3),indicating great potential of geothermal exploitation.展开更多
In this work,to develop strong near-infrared circularly polarized luminescent(NIR-CPL)emitters,a pair of ytterbium helicates,namely,[Yb_(2)(R-BTHP)_(4)]_(2)−and[Yb_(2)(S-BTHP)_(4)]^(2−),based on binaphthol-modified b...In this work,to develop strong near-infrared circularly polarized luminescent(NIR-CPL)emitters,a pair of ytterbium helicates,namely,[Yb_(2)(R-BTHP)_(4)]_(2)−and[Yb_(2)(S-BTHP)_(4)]^(2−),based on binaphthol-modified bis-β-diketones was synthesized.X-ray crystallography analysis confirms the formation of the homochiral quadruple-stranded dinuclear structure of the helicate.CPL spectroscopy measurements show that the helicates exhibit an exceptionally high luminescence dissymmetry factor(|g_(lum)|)of 0.81 at 980 nm,the highest value reported for Yb-CPL materials,as well as the largest near-infrared circularly polarized luminescence brightness(B_(CPL),821 M^(−1)cm^(−1)).We proposed that the high glum value originates from the rigid and high symmetry of the helical structure,and the perfect eight-coordinated square antiprismatic configuration(8-SAPR)around the Yb^(3+) ion.This work offers an example for the design of chiral CPLemitting lanthanide complexes with large glum values.In view of the 980 nm light localized at the biologically relative NIR emission window,the helicates reported herein show promising applications in biologically relevant sensors and 980 nm fiber lasers.展开更多
文摘Investigating the formation mechanisms of carbonate geothermal reservoirs is of theoretical and practical significance for summarizing the formation pattern of geothermal resources and further guiding their effective exploitation.The Beijing-Tianjin-Hebei Plain(BTHP),predominantly located within the Jizhong Depression and Cangxian Uplift in the Bohai Bay Basin,serves as the primary region for geothermal exploitation and utilization in China.More than 1500 geothermal wells have been drilled therein,with water temperature at the wellhead ranging from 55 to 110°C,single-well flow rate ranging between 80 and 120 m^(3)/h,and cumulative heating area exceeding 100×10^(6)m^(3).However,the exploration and research in the region remain limited overall.As per the previous geothermal and petroleum exploration results and the latest geothermal drilling data,this study comprehensively evaluated the geothermal resources of karst geothermal reservoirs.The results show that two suites of carbonate karst reservoirs,namely the Jxw Formation and the Ordovician strata,have primarily developed in the BTHP,and their formation and evolution can be divided into four stages:the Mesoproterozoic-Early Paleozoic stage with carbonate sedimentation and the development of interlayer karst,the Late Paleozoic stage with the development of direct sedimentary cover,the Mesozoic stage with compressional uplifting and development of buried hill karst,and the Cenozoic stage with regional cover deposition and the modification and finalization of karst geothermal reservoirs.Accordingly,the porosity evolution history of the geothermal reservoirs is composed of three stages,namely a significant decrease followed by a minor increase,a gradual decline,and then a small fluctuation from increase to decrease before slowly rising again.The karstification in geothermal reservoirs can be summarized into quasi-syngenetic karstification,epigenetic karstification,and burial karstification,which can be subdivided into seven subcategories.The carbonate geothermal reservoirs in the study area boast total geothermal resources of 53.821×10^(9)GJ,or 184.155×10^(9)t of standard coal equivalent(tce),and the annual exploitable geothermal resources in the urban area can heat an area of(400‒500)×10^(6)m^(3),indicating great potential of geothermal exploitation.
基金financially supported by the National Natural Science Foundation of China(no.52273263,52203219,51872077 and 52073080)Science and Technology Plan of Inner Mongolia Autonomous Region(2020GG0164)Scientific Research Project of Basic Scientific Research Operating Expenses of Colleges and Universities in Heilongjiang Province(2021-KYYWF-0029 and 2021-KYYWF-0041).
文摘In this work,to develop strong near-infrared circularly polarized luminescent(NIR-CPL)emitters,a pair of ytterbium helicates,namely,[Yb_(2)(R-BTHP)_(4)]_(2)−and[Yb_(2)(S-BTHP)_(4)]^(2−),based on binaphthol-modified bis-β-diketones was synthesized.X-ray crystallography analysis confirms the formation of the homochiral quadruple-stranded dinuclear structure of the helicate.CPL spectroscopy measurements show that the helicates exhibit an exceptionally high luminescence dissymmetry factor(|g_(lum)|)of 0.81 at 980 nm,the highest value reported for Yb-CPL materials,as well as the largest near-infrared circularly polarized luminescence brightness(B_(CPL),821 M^(−1)cm^(−1)).We proposed that the high glum value originates from the rigid and high symmetry of the helical structure,and the perfect eight-coordinated square antiprismatic configuration(8-SAPR)around the Yb^(3+) ion.This work offers an example for the design of chiral CPLemitting lanthanide complexes with large glum values.In view of the 980 nm light localized at the biologically relative NIR emission window,the helicates reported herein show promising applications in biologically relevant sensors and 980 nm fiber lasers.
