As the world’s second largest economy experiencing rapid economic growth,China has a huge demand for metals and energy.In recent years,China ranks first,among all the countries in the world,in the production and cons...As the world’s second largest economy experiencing rapid economic growth,China has a huge demand for metals and energy.In recent years,China ranks first,among all the countries in the world,in the production and consumption of several metals such as copper,gold,and rare earth elements.Bioleaching,which is an approach for mining low grade and refractory ores,has been applied in industrial production,and bioleaching has made great contributions to the development of the Chinese mining industry.The exploration and application of bioleaching in China are reviewed in this study.Production and consumption trends of several metals in China over the past decade are reviewed.Technological processes at key bioleaching operations in China,such as at the Zijinshan Copper Mine and Mianhuakeng Uranium Mine,are presented.Also,the current challenges faced by bioleaching operations in China are introduced.Moreover,prospects such as efficiency improvement and environmental protection are proposed based on the current situation in the Chinese bioleaching industry.展开更多
The major scientific goals of the DArk Matter Particle Explorer(DAMPE)are to study cosmicray electrons(including positrons)and gamma rays from 5 GeV to 10 TeV and nuclei from Z=1 to 26 up to 100 TeV.The deposited ener...The major scientific goals of the DArk Matter Particle Explorer(DAMPE)are to study cosmicray electrons(including positrons)and gamma rays from 5 GeV to 10 TeV and nuclei from Z=1 to 26 up to 100 TeV.The deposited energy measured by the Bismuth Germanate Oxide(BGO)calorimeter of DAMPE is affected by fluorescence attenuation in BGO crystals that are 600 mm long.In this work,an in-orbit attenuation calibration method is reported,and energy correction of the sensitive detector unit of the BGO calorimeter is also presented.展开更多
A method of identifying positron/electron species from the cosmic rays was studied in the DArk Matter Particle Explorer(DAMPE)experiment.As there is no onboard magnet on the satellite,the different features imposed by...A method of identifying positron/electron species from the cosmic rays was studied in the DArk Matter Particle Explorer(DAMPE)experiment.As there is no onboard magnet on the satellite,the different features imposed by the geomagnetic field on these two species were exploited for the particle identification.Application of this method to the simulation of on-orbit electrons/positrons/protons and the real flight data proves that separately measuring the CR positrons/electrons with DAMPE is feasible,though limited by the field of view for the present observation data.Further analysis on the positron flux with this method can be expected in the future.展开更多
Cast-in-place pile foundations are widely used in permafrost regions to support buildings.The stability of cast-in-place pile foundations is highly sensitive to permafrost thermal regime changes.Permafrost degradation...Cast-in-place pile foundations are widely used in permafrost regions to support buildings.The stability of cast-in-place pile foundations is highly sensitive to permafrost thermal regime changes.Permafrost degradation caused by climate change is increasing the disaster risk of castin-place pile foundations.However,proactive cooling methods for cast-in-place pile foundations are seldom reported.The cold energy produced by two-phase closed thermosyphons(TPCTs)can efficiently prevent the permafrost thermal regime from being disturbed by engineering activities and climate change.TPCTs were installed in a concrete pile forming a thermal pile.Then,a model experiment was conducted to explore the thermal regime,influence scope,dissipation process of cold energy,and freezing strength of the thermal pile.The results indicated that the thermal pile may significantly cool the foundation soil.Most of cold energy produced by the thermal pile dissipated during the warm period,and the cooling scope of the thermal pile can cover the area within a 40 cm(twice the pile diameter)radius around the pile.Additionally,the TPCTs can significantly improve freezing strength between the thermal pile and frozen soil.The lesson learned from this study can provide a new approach to control the thermal regime of cast-in-place pile foundation in permafrost,which was of valuable to the construction of pile foundations in cold regions.展开更多
Precise measurements of the energy spectra of cosmic rays(CRs)show various kinds of features deviating from single power-laws,which give very interesting and important implications on their origin and propagation.Prev...Precise measurements of the energy spectra of cosmic rays(CRs)show various kinds of features deviating from single power-laws,which give very interesting and important implications on their origin and propagation.Previous measurements from a few balloon and space experiments indicate the existence of spectral softenings around 10 TV for protons(and probably also for Helium nuclei).Very recently,the DArk Matter Particle Explorer(DAMPE)measurement about the proton spectrum clearly reveals such a softening with a high significance.Here we study the implications of these new measurements,as well as the groundbased indirect measurements,on the origin of CRs.We find that a single component of CRs fails to fit the spectral softening and the air shower experiment data simultaneously.In the framework of multiple components,we discuss two possible scenarios,the multiple source population scenario and the background plus nearby source scenario.Both scenarios give reasonable fits to the wide-band data from TeV to 100 PeV energies.Considering the anisotropy observations,the nearby source model is favored.展开更多
基金This work was financially supported by the National Natural Science Foundation of China(No.52034001).
文摘As the world’s second largest economy experiencing rapid economic growth,China has a huge demand for metals and energy.In recent years,China ranks first,among all the countries in the world,in the production and consumption of several metals such as copper,gold,and rare earth elements.Bioleaching,which is an approach for mining low grade and refractory ores,has been applied in industrial production,and bioleaching has made great contributions to the development of the Chinese mining industry.The exploration and application of bioleaching in China are reviewed in this study.Production and consumption trends of several metals in China over the past decade are reviewed.Technological processes at key bioleaching operations in China,such as at the Zijinshan Copper Mine and Mianhuakeng Uranium Mine,are presented.Also,the current challenges faced by bioleaching operations in China are introduced.Moreover,prospects such as efficiency improvement and environmental protection are proposed based on the current situation in the Chinese bioleaching industry.
基金the project the Joint Funds of the National Natural Science Foundation of China(Nos.U1738135,U1738208 and U1738139)the National Natural Science Foundation of China(Nos.11673021 and 11705197)the National Key Research and Development Program of China(2016YFA0400200 and 2016YFA0400202)。
文摘The major scientific goals of the DArk Matter Particle Explorer(DAMPE)are to study cosmicray electrons(including positrons)and gamma rays from 5 GeV to 10 TeV and nuclei from Z=1 to 26 up to 100 TeV.The deposited energy measured by the Bismuth Germanate Oxide(BGO)calorimeter of DAMPE is affected by fluorescence attenuation in BGO crystals that are 600 mm long.In this work,an in-orbit attenuation calibration method is reported,and energy correction of the sensitive detector unit of the BGO calorimeter is also presented.
基金supported by the Outstanding Youth Science Foundation of NSFC(Grant No.12022503)the Joint Funds of the National Natural Science Foundation of China(Grant Nos.U1738208,U1738139,U1738135 and U1738207)+2 种基金the National Natural Science Foundation of China(Grant Nos.11673021,11705197,11773085 and 11851302)the National Key Research and Development Program of China(Grant No.2016YFA0400200)Youth Innovation Promotion Association CAS(Grant No.2021450)。
文摘A method of identifying positron/electron species from the cosmic rays was studied in the DArk Matter Particle Explorer(DAMPE)experiment.As there is no onboard magnet on the satellite,the different features imposed by the geomagnetic field on these two species were exploited for the particle identification.Application of this method to the simulation of on-orbit electrons/positrons/protons and the real flight data proves that separately measuring the CR positrons/electrons with DAMPE is feasible,though limited by the field of view for the present observation data.Further analysis on the positron flux with this method can be expected in the future.
基金the Second Tibetan Plateau Scientific Expedition and Research(STEP)program(2019QZKK0905)the National Natural Science Foundation of China(42001063,41961011)+1 种基金the Open Fund of State Key Laboratory of Road Engineering Safety and Health in Cold and High-Altitude Regions(YGY2020KYPT-04)CCCC Scientific and Technological Research Program(2020-ZJKJPTJS04).
文摘Cast-in-place pile foundations are widely used in permafrost regions to support buildings.The stability of cast-in-place pile foundations is highly sensitive to permafrost thermal regime changes.Permafrost degradation caused by climate change is increasing the disaster risk of castin-place pile foundations.However,proactive cooling methods for cast-in-place pile foundations are seldom reported.The cold energy produced by two-phase closed thermosyphons(TPCTs)can efficiently prevent the permafrost thermal regime from being disturbed by engineering activities and climate change.TPCTs were installed in a concrete pile forming a thermal pile.Then,a model experiment was conducted to explore the thermal regime,influence scope,dissipation process of cold energy,and freezing strength of the thermal pile.The results indicated that the thermal pile may significantly cool the foundation soil.Most of cold energy produced by the thermal pile dissipated during the warm period,and the cooling scope of the thermal pile can cover the area within a 40 cm(twice the pile diameter)radius around the pile.Additionally,the TPCTs can significantly improve freezing strength between the thermal pile and frozen soil.The lesson learned from this study can provide a new approach to control the thermal regime of cast-in-place pile foundation in permafrost,which was of valuable to the construction of pile foundations in cold regions.
基金the Na-tional Key Research and Development Program of China(No.2016YFA0400200)the National Natural Science Foundation of China(Nos.11722328,11525313,U1738205,and 11851305)the 100 Talents Program of Chinese Academy of Sciences.
文摘Precise measurements of the energy spectra of cosmic rays(CRs)show various kinds of features deviating from single power-laws,which give very interesting and important implications on their origin and propagation.Previous measurements from a few balloon and space experiments indicate the existence of spectral softenings around 10 TV for protons(and probably also for Helium nuclei).Very recently,the DArk Matter Particle Explorer(DAMPE)measurement about the proton spectrum clearly reveals such a softening with a high significance.Here we study the implications of these new measurements,as well as the groundbased indirect measurements,on the origin of CRs.We find that a single component of CRs fails to fit the spectral softening and the air shower experiment data simultaneously.In the framework of multiple components,we discuss two possible scenarios,the multiple source population scenario and the background plus nearby source scenario.Both scenarios give reasonable fits to the wide-band data from TeV to 100 PeV energies.Considering the anisotropy observations,the nearby source model is favored.