Aeolian processes have been studied extensively at low elevations,but have been relatively little studied at high elevations.Aeolian sediments are widely distributed in the Yarlung Zangbo River basin,southern Tibetan ...Aeolian processes have been studied extensively at low elevations,but have been relatively little studied at high elevations.Aeolian sediments are widely distributed in the Yarlung Zangbo River basin,southern Tibetan Plateau,which is characterized by low pressure and low temperature.Here,we comprehensively analyzed the wind regime using data since 1980 from 11 meteorological stations in the study area,and examined the interaction between the near-surface wind and aeolian environment.The wind environment exhibited significant spatial and temporal variation,and mean wind speed has generally decreased on both annual and seasonal bases since 1980,at an average of 0.181 m/(s•10a).This decrease resulted from the reduced contribution of maximum wind speed,and depended strongly on variations of the frequency of sand-driving winds.The drift potential and related parameters also showed obvious spatial and temporal variation,with similar driving forces for the wind environment.The strength of the wind regime affected the formation and development of the aeolian geomorphological pattern,but with variation caused by local topography and sediment sources.The drift potential and resultant drift direction were two key parameters,as they quantify the dynamic conditions and depositional orientation of the aeolian sediments.Wind affected the spatial variation in sediment grain size,but the source material and complex topographic effects on the near-surface wind were the underlying causes for the grain size distribution of aeolian sands.These results will support efforts to control aeolian desertification in the basin and improve our understanding of aeolian processes in high-elevation environments.展开更多
The upcoming COP23 at Bonn of the UN and its UNFCCC must outline how its COP21 objectives are to be promoted by means of concrete international and national management. Only a massive replacement of fossil fuels and w...The upcoming COP23 at Bonn of the UN and its UNFCCC must outline how its COP21 objectives are to be promoted by means of concrete international and national management. Only a massive replacement of fossil fuels and wood coal by solar power parks, can wind power and atomic power save mankind from the grave threats of global warming. This paper presents a tentative estimation of what is involved with regard to the fulfilment of COP21 ＇s GOAL II--decarbonisation to 30-40 per cent of 2005 level of emissions.展开更多
Dune sand is a very abundant material in south of Algeria. Its high silica content gives a partial pozzolanic reactivity due to its crystalline state. This paper investigates the evolution of cement hydration based on...Dune sand is a very abundant material in south of Algeria. Its high silica content gives a partial pozzolanic reactivity due to its crystalline state. This paper investigates the evolution of cement hydration based on a binary addition particularly the reactivity of dune sand finely ground in the presence of an amorphous addition: silica fume or blast furnace slag. Thus, four combinations of binary additions by substitution have been chosen. The X-ray diffraction analyses performed on cement pastes containing additions have shown the importance of the mineralogy and silica content of additions on their pozzolanic reactivity. Dune sand becomes reactive at long term, especially when associated up to 10% of amorphous addition (blast furnace slag or silica fume). It results an increasing in mechanical strength of Ultra High Performance Concrete (UHPC) and an improvement of the microstructure.展开更多
In August 1963, Israel＇s Prime Minister Levi Eshkol initiated the procedure for terminating the martial law in effect since the end of the War of Independence （1948） with regard to Israeli Arabs. Martial law discri...In August 1963, Israel＇s Prime Minister Levi Eshkol initiated the procedure for terminating the martial law in effect since the end of the War of Independence （1948） with regard to Israeli Arabs. Martial law discriminated against Israel＇s Arab minority, as opposed to the majority of Israel＇s society, as part of different issues bound up with this population＇s daily functioning. The aim of the paper is to present the reasons why Eshkol＇s doing away with the martial law stemmed was its ineffectiveness, while the other, and this makes up the core of our concern here, was his changing attitude toward the Arab minority in Israel, by contrast with that of his predecessor, David Ben Gurion The main conclusion of the paper is that even though Eshkol＇s ideas about the Arab minority were not very different from Ben Gurion＇s ideas one insisted on maintaining the military government in Israel, while the other saw this as unnecessary, and so brought it to an end. In August 1963, a few months after assuming office, Israel＇s Prime Minister Levi Eshkol initiated the first steps leading to the annulment of military rulet which had applied to Arabs in the State of Israel ever since the end of the War of Independence （1948）. This process was concluded some three years later. Military rule was lifted in effect on December 1, 1966. In the presentation, the author would like to look into the considerations which prompted Eshkol to take such a step, in light of the fact that his predecessor, Ben Gurion, was a staunch opponent of annulling the military regime, convinced as he was, even after the conclusion of his term in office, that the current state of affairs should remain in effect.展开更多
Banded iron formation and Cu-Zn sulfide deposits within volcanic-argillaceous sequences(as volcanogenic massive sulphide deposits(VMS)-like type) occur together in the Qingyuan greenstone belt of the North China Crato...Banded iron formation and Cu-Zn sulfide deposits within volcanic-argillaceous sequences(as volcanogenic massive sulphide deposits(VMS)-like type) occur together in the Qingyuan greenstone belt of the North China Craton,recording the first appearance of oxidized ores and sulfide ores co-existing in the early Earth.The unique metal co-existing deposits should meet two requirements:tectonic setting and sedimentary environment.As regards to tectonic setting,plate-like tectonics might have started since the end of the Neoarchean because continents had grown large enough and there occurred volcanic arcs and backarc basins similar to modern ones in a way.Partial melting of subducted continental crust is conductive to providing ore-forming elements.As for sedimentary environment,late Neoarchean seawater was rich in Fe^(2+) and anoxic.Instantaneous oxidation of the seawater resulted possibly from frequent submarine volcanic eruptions and facilitated precipitation of the banded iron formation.At this point,it is also favorable for the enrichment of Cu and Zn ions in seawater.The VMS-like deposits tended to form when the seawater was reduced again.Studies of isotopic elements like sulfur,oxygen,iron and silicon support the above geological processes.It is shown that the geologic conditions only existed in the late Neoarchean and Paleoproterozoic for a short period of time.The banded iron formations disappeared around 1.85 Ga,and the associated sulfide metal deposits also became dominant sedimentary exhalative deposits in the meso-Neoproterozoic Boring Billion,as a result of increasing oxidation of the oceans and the increasing maturity of the continental crust.This study is significant not only for decoding metallogenic genesis but also helping understand rapid change in Precambrian tectonic regimes and Earth’s environments.展开更多
T’he welfare state systems that the developed countries in the West established beginning roughly in the 1920s and continuing until after World War II were based on the cooperation among three parlies: the employees...T’he welfare state systems that the developed countries in the West established beginning roughly in the 1920s and continuing until after World War II were based on the cooperation among three parlies: the employees’ organization, the employers’ organization and the state. Corporatism here refers to the welfare systems of those countries, the basic features of which may be defined as follows:展开更多
基金the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(2019QZKK0602)the Open Foundation of MOE Key Laboratory of Western China's Environmental System,Lanzhou University and the Fundamental Research Funds for the Central Universities(lzujbky-2020-kb01)。
文摘Aeolian processes have been studied extensively at low elevations,but have been relatively little studied at high elevations.Aeolian sediments are widely distributed in the Yarlung Zangbo River basin,southern Tibetan Plateau,which is characterized by low pressure and low temperature.Here,we comprehensively analyzed the wind regime using data since 1980 from 11 meteorological stations in the study area,and examined the interaction between the near-surface wind and aeolian environment.The wind environment exhibited significant spatial and temporal variation,and mean wind speed has generally decreased on both annual and seasonal bases since 1980,at an average of 0.181 m/(s•10a).This decrease resulted from the reduced contribution of maximum wind speed,and depended strongly on variations of the frequency of sand-driving winds.The drift potential and related parameters also showed obvious spatial and temporal variation,with similar driving forces for the wind environment.The strength of the wind regime affected the formation and development of the aeolian geomorphological pattern,but with variation caused by local topography and sediment sources.The drift potential and resultant drift direction were two key parameters,as they quantify the dynamic conditions and depositional orientation of the aeolian sediments.Wind affected the spatial variation in sediment grain size,but the source material and complex topographic effects on the near-surface wind were the underlying causes for the grain size distribution of aeolian sands.These results will support efforts to control aeolian desertification in the basin and improve our understanding of aeolian processes in high-elevation environments.
文摘The upcoming COP23 at Bonn of the UN and its UNFCCC must outline how its COP21 objectives are to be promoted by means of concrete international and national management. Only a massive replacement of fossil fuels and wood coal by solar power parks, can wind power and atomic power save mankind from the grave threats of global warming. This paper presents a tentative estimation of what is involved with regard to the fulfilment of COP21 ＇s GOAL II--decarbonisation to 30-40 per cent of 2005 level of emissions.
文摘Dune sand is a very abundant material in south of Algeria. Its high silica content gives a partial pozzolanic reactivity due to its crystalline state. This paper investigates the evolution of cement hydration based on a binary addition particularly the reactivity of dune sand finely ground in the presence of an amorphous addition: silica fume or blast furnace slag. Thus, four combinations of binary additions by substitution have been chosen. The X-ray diffraction analyses performed on cement pastes containing additions have shown the importance of the mineralogy and silica content of additions on their pozzolanic reactivity. Dune sand becomes reactive at long term, especially when associated up to 10% of amorphous addition (blast furnace slag or silica fume). It results an increasing in mechanical strength of Ultra High Performance Concrete (UHPC) and an improvement of the microstructure.
文摘In August 1963, Israel＇s Prime Minister Levi Eshkol initiated the procedure for terminating the martial law in effect since the end of the War of Independence （1948） with regard to Israeli Arabs. Martial law discriminated against Israel＇s Arab minority, as opposed to the majority of Israel＇s society, as part of different issues bound up with this population＇s daily functioning. The aim of the paper is to present the reasons why Eshkol＇s doing away with the martial law stemmed was its ineffectiveness, while the other, and this makes up the core of our concern here, was his changing attitude toward the Arab minority in Israel, by contrast with that of his predecessor, David Ben Gurion The main conclusion of the paper is that even though Eshkol＇s ideas about the Arab minority were not very different from Ben Gurion＇s ideas one insisted on maintaining the military government in Israel, while the other saw this as unnecessary, and so brought it to an end. In August 1963, a few months after assuming office, Israel＇s Prime Minister Levi Eshkol initiated the first steps leading to the annulment of military rulet which had applied to Arabs in the State of Israel ever since the end of the War of Independence （1948）. This process was concluded some three years later. Military rule was lifted in effect on December 1, 1966. In the presentation, the author would like to look into the considerations which prompted Eshkol to take such a step, in light of the fact that his predecessor, Ben Gurion, was a staunch opponent of annulling the military regime, convinced as he was, even after the conclusion of his term in office, that the current state of affairs should remain in effect.
基金supported by the Major Project of the National Natural Science Foundation of China (41890834 and 92162323)the Strategic Pilot Technology (B-type) Project of Chinese Academy of Sciences (CAS) (XDB18030205)+1 种基金the Key International Program of CAS (132A11KYSB20180042)the Key Research Program of Frontier Science, CAS (QYZDY-SSW-DQC017)。
文摘Banded iron formation and Cu-Zn sulfide deposits within volcanic-argillaceous sequences(as volcanogenic massive sulphide deposits(VMS)-like type) occur together in the Qingyuan greenstone belt of the North China Craton,recording the first appearance of oxidized ores and sulfide ores co-existing in the early Earth.The unique metal co-existing deposits should meet two requirements:tectonic setting and sedimentary environment.As regards to tectonic setting,plate-like tectonics might have started since the end of the Neoarchean because continents had grown large enough and there occurred volcanic arcs and backarc basins similar to modern ones in a way.Partial melting of subducted continental crust is conductive to providing ore-forming elements.As for sedimentary environment,late Neoarchean seawater was rich in Fe^(2+) and anoxic.Instantaneous oxidation of the seawater resulted possibly from frequent submarine volcanic eruptions and facilitated precipitation of the banded iron formation.At this point,it is also favorable for the enrichment of Cu and Zn ions in seawater.The VMS-like deposits tended to form when the seawater was reduced again.Studies of isotopic elements like sulfur,oxygen,iron and silicon support the above geological processes.It is shown that the geologic conditions only existed in the late Neoarchean and Paleoproterozoic for a short period of time.The banded iron formations disappeared around 1.85 Ga,and the associated sulfide metal deposits also became dominant sedimentary exhalative deposits in the meso-Neoproterozoic Boring Billion,as a result of increasing oxidation of the oceans and the increasing maturity of the continental crust.This study is significant not only for decoding metallogenic genesis but also helping understand rapid change in Precambrian tectonic regimes and Earth’s environments.
文摘T’he welfare state systems that the developed countries in the West established beginning roughly in the 1920s and continuing until after World War II were based on the cooperation among three parlies: the employees’ organization, the employers’ organization and the state. Corporatism here refers to the welfare systems of those countries, the basic features of which may be defined as follows:
