The formation and disruption of supercontinents have significantly impacted mantle dynamics, solid earth processes, surface environments and the biogeochemical cycle. In the early history of the Earth, the collision o...The formation and disruption of supercontinents have significantly impacted mantle dynamics, solid earth processes, surface environments and the biogeochemical cycle. In the early history of the Earth, the collision of parallel intra-oceanic arcs was an important process in building embryonic continents. Superdownwelling along Y-shaped triple junctions might have been one of the important processes that aided in the rapid assembly of continental fragments into closely packed supercontinents. Various models have been proposed for the fragmentation of supercontinents including thermal blanket and superplume hypotheses. The reassembly of supercontinents after breakup and the ocean closure occurs through ＂introversion＂, ＂extroversion＂ or a combination of both, and is characterized by either Pacific-type or Atlantic-type ocean closure. The breakup of supercontinents and development of hydro- thermal system in rifts with granitic basement create anomalous chemical environments enriched in nutri- ents, which serve as the primary building blocks of the skeleton and bone of early modern life forms. A typical example is the rifting of the Rodinia supercontinent, which opened up an N--S oriented sea way along which nutrient enriched upwelling brought about a habitable geochemical environment. The assembly of supercontinents also had significant impact on life evolution. The role played by the Cambrian Gondwana assembly has been emphasized in many models, including the formation of ＇Trans- gondwana Mountains＇ that might have provided an effective source of rich nutrients to the equatorial waters, thus aiding the rapid increase in biodiversity. The planet has witnessed several mass extinction events during its history, mostly connected with major climatic fluctuations including global cooling and warming events, major glaciations, fluctuations in sea level, global anoxia, volcanic eruptions, asteroid impacts and gamma radiation. Some recent models speculate a relationship between superplumes, supercontinent breaku展开更多
In geological history, one major life explosion and five mass extinction events occurred. These major biological and environmental events affected the evolution of the Earth ecosystem and controlled the formation of o...In geological history, one major life explosion and five mass extinction events occurred. These major biological and environmental events affected the evolution of the Earth ecosystem and controlled the formation of organic-rich strata. The life explosion occurred in Cambrian and the five mass extinction events happened at the end of Ordovician, Late Devonian, end of Permian, end of Triassic, and end of Cretaceous, respectively. They are corresponded to the formation of multiple suites of organic-rich strata globally, which are crucial to the formation, evolution and distribution of the fossil energy on Earth. China’s energy is characterized by "unlimited new energy, rich in coal but insufficient in oil and gas ", and it is determined to rely on new energy sources to achieve " energy independence " and carbon neutrality. From the perspective of the Earth system evolution, we investigate the multiple relationships between energy and Earth, energy and environment, as well as energy and human beings, and carry out comprehensive research on energy. Energy science refers to the science of studying the various energy sources formation and distribution, evaluation and selection, production and utilization, orderly replacement, development prospects, etc. in temporal and spatial scales based on the evolution of the Earth system. The connotation of energy science includes three core contents:(1) The relationship between the Earth and energy, including the formation of energy in the Earth system and the feedback of energy consumption to the Earth’s climate and environment;(2) The relationship between the Earth environment and the human beings, including the Earth environment breeding human beings and human activities transforming the earth environment;(3) The relationship between the energy and the human beings, including the development of energy technology by human beings and the progress of human society driven by energy utilization. The energy science focuses on the formation and development of fossil energy, devel展开更多
In the present study nano-tungsten carbide particles were generated in a wire explosion process.The plasma generated during the wire explosion process was analyzed using optical emission spectroscopy（OES）.The impact...In the present study nano-tungsten carbide particles were generated in a wire explosion process.The plasma generated during the wire explosion process was analyzed using optical emission spectroscopy（OES）.The impact of ambient pressure on the plasma temperature,electron density and plasma lifetime was studied.Lifetime variations of the plasma produced under different experimental conditions were analyzed.The produced nanoparticles were characterized through wide angle X-ray diffraction（WAXD） and transmission electron microscopy（TEM） studies. Particles produced with a negative DC charging voltage had a larger mean size when compared to a positive charging voltage.Polarity dependence on the plasma duration was observed where plasma was sustained for a longer duration with a negative DC charging voltage.展开更多
A method of estimating the safe storage life （τ）, self-accelerating decomposition temperature （TsADT） and critical temperature of thermal explosion （Tb） of double-base propellant using isothermal and non-isothe...A method of estimating the safe storage life （τ）, self-accelerating decomposition temperature （TsADT） and critical temperature of thermal explosion （Tb） of double-base propellant using isothermal and non-isothermal decomposition behaviours is presented. For double-base propellant composed of 56±1wt% of nitrocellulose （NC）, 27±0.5wt% of nitroglycerine （NG）, 8.15±0.15wt% of dinitrotoluene （DNT）, 2.5±0.1wt% of methyl centralite, 5.0±0.15wt% of catalyst and 1.0±0.1wt% of other, the values of r of 49.4 years at 40℃, of TSAOT of 151.35℃ and of Tb of 163.01℃ were obtained.展开更多
文摘The formation and disruption of supercontinents have significantly impacted mantle dynamics, solid earth processes, surface environments and the biogeochemical cycle. In the early history of the Earth, the collision of parallel intra-oceanic arcs was an important process in building embryonic continents. Superdownwelling along Y-shaped triple junctions might have been one of the important processes that aided in the rapid assembly of continental fragments into closely packed supercontinents. Various models have been proposed for the fragmentation of supercontinents including thermal blanket and superplume hypotheses. The reassembly of supercontinents after breakup and the ocean closure occurs through ＂introversion＂, ＂extroversion＂ or a combination of both, and is characterized by either Pacific-type or Atlantic-type ocean closure. The breakup of supercontinents and development of hydro- thermal system in rifts with granitic basement create anomalous chemical environments enriched in nutri- ents, which serve as the primary building blocks of the skeleton and bone of early modern life forms. A typical example is the rifting of the Rodinia supercontinent, which opened up an N--S oriented sea way along which nutrient enriched upwelling brought about a habitable geochemical environment. The assembly of supercontinents also had significant impact on life evolution. The role played by the Cambrian Gondwana assembly has been emphasized in many models, including the formation of ＇Trans- gondwana Mountains＇ that might have provided an effective source of rich nutrients to the equatorial waters, thus aiding the rapid increase in biodiversity. The planet has witnessed several mass extinction events during its history, mostly connected with major climatic fluctuations including global cooling and warming events, major glaciations, fluctuations in sea level, global anoxia, volcanic eruptions, asteroid impacts and gamma radiation. Some recent models speculate a relationship between superplumes, supercontinent breaku
基金Supported by the National Natural Science Foundation of China(41902151)。
文摘In geological history, one major life explosion and five mass extinction events occurred. These major biological and environmental events affected the evolution of the Earth ecosystem and controlled the formation of organic-rich strata. The life explosion occurred in Cambrian and the five mass extinction events happened at the end of Ordovician, Late Devonian, end of Permian, end of Triassic, and end of Cretaceous, respectively. They are corresponded to the formation of multiple suites of organic-rich strata globally, which are crucial to the formation, evolution and distribution of the fossil energy on Earth. China’s energy is characterized by "unlimited new energy, rich in coal but insufficient in oil and gas ", and it is determined to rely on new energy sources to achieve " energy independence " and carbon neutrality. From the perspective of the Earth system evolution, we investigate the multiple relationships between energy and Earth, energy and environment, as well as energy and human beings, and carry out comprehensive research on energy. Energy science refers to the science of studying the various energy sources formation and distribution, evaluation and selection, production and utilization, orderly replacement, development prospects, etc. in temporal and spatial scales based on the evolution of the Earth system. The connotation of energy science includes three core contents:(1) The relationship between the Earth and energy, including the formation of energy in the Earth system and the feedback of energy consumption to the Earth’s climate and environment;(2) The relationship between the Earth environment and the human beings, including the Earth environment breeding human beings and human activities transforming the earth environment;(3) The relationship between the energy and the human beings, including the development of energy technology by human beings and the progress of human society driven by energy utilization. The energy science focuses on the formation and development of fossil energy, devel
文摘In the present study nano-tungsten carbide particles were generated in a wire explosion process.The plasma generated during the wire explosion process was analyzed using optical emission spectroscopy（OES）.The impact of ambient pressure on the plasma temperature,electron density and plasma lifetime was studied.Lifetime variations of the plasma produced under different experimental conditions were analyzed.The produced nanoparticles were characterized through wide angle X-ray diffraction（WAXD） and transmission electron microscopy（TEM） studies. Particles produced with a negative DC charging voltage had a larger mean size when compared to a positive charging voltage.Polarity dependence on the plasma duration was observed where plasma was sustained for a longer duration with a negative DC charging voltage.
基金We are grateful to the National Natural Science Foundation of China （No. 20573098）
文摘A method of estimating the safe storage life （τ）, self-accelerating decomposition temperature （TsADT） and critical temperature of thermal explosion （Tb） of double-base propellant using isothermal and non-isothermal decomposition behaviours is presented. For double-base propellant composed of 56±1wt% of nitrocellulose （NC）, 27±0.5wt% of nitroglycerine （NG）, 8.15±0.15wt% of dinitrotoluene （DNT）, 2.5±0.1wt% of methyl centralite, 5.0±0.15wt% of catalyst and 1.0±0.1wt% of other, the values of r of 49.4 years at 40℃, of TSAOT of 151.35℃ and of Tb of 163.01℃ were obtained.
