The average variational principle was employed in this paper to study the evolution of large-scale and slowly varying Rossby wave packet with basic flow both in barotropic and baroclinic atmospheres. The evolution of ...The average variational principle was employed in this paper to study the evolution of large-scale and slowly varying Rossby wave packet with basic flow both in barotropic and baroclinic atmospheres. The evolution of the structure of Rossby wave packet with both time and space was studied. The results obtained in this paper are similar to the results of by WKBJ method. In addition, the dispersive process of the wave packet was analysed by taking Gaussian type wave packet as an initial disturbance. The valid time scale for application of wave packet theory in the atmosphere was obtained.展开更多
ThiS work was one of the key State-funded projects for natural sciences during the period from 1988-1992 under the joint sponsorship of the CAS,the State Planning Commission,the Institute of Geography and the Yellow R...ThiS work was one of the key State-funded projects for natural sciences during the period from 1988-1992 under the joint sponsorship of the CAS,the State Planning Commission,the Institute of Geography and the Yellow River Harnessing Committee under the Ministry of Water Conservancy.The project involves some 140 scientists from 19 research units,such as institutes and universities.Its purpose is to make clear the vicissitudes of environmental evolution and water-and-soil changes in the Yel-展开更多
Phase evolution and magnetic properties of (Nd_o.95La_0.05)9.5-11Febal.M_2B10.5. where M=Cr, Ti, Nb, V, Mo, Zr, Hf, Ta, Mn or W, melt spun ribbons have been investigated. Almost all the alloy ribbons. except for(Nd_0....Phase evolution and magnetic properties of (Nd_o.95La_0.05)9.5-11Febal.M_2B10.5. where M=Cr, Ti, Nb, V, Mo, Zr, Hf, Ta, Mn or W, melt spun ribbons have been investigated. Almost all the alloy ribbons. except for(Nd_0.95La_0.05)_9.5Fe_78M_2B_10.5(M=Mo and Mn),consist merely two magnetic phases, namely α-Fe and R_2Fe_14B, which display a better combination of _iH_c and magnetic energy product. Remanence (Br) and coercivity (i_H_c) values in the range of 8.0 to 9.1 kG and 9.5 to 18.9 kOe. respectively, can be achieved. Among compositions studied, the Ti and W-substitutions were found to be most effective in increasing the Br and i_H_c, respectively. For a fixed refractory metal substitution, namely, M=C_r, Ti or Nb, an increase in the total rare earth concentration resulted in nanocomposites of small grain sizes and a high volume fraction of the R_2Fe_14B phase, leading to an increase in the magnetic properties.展开更多
A nanostructured Hf11Ni89 ribbon sample was prepared by melt-spinning. It was found that the as-quenched sample is composed of a major HfNi5 compound nanophase and an interfacial magnetic Ni(Hf) solid solution phase. ...A nanostructured Hf11Ni89 ribbon sample was prepared by melt-spinning. It was found that the as-quenched sample is composed of a major HfNi5 compound nanophase and an interfacial magnetic Ni(Hf) solid solution phase. The structure evolution of the sample was studied by using X-ray difFraction (XRD), transmission electron microscopy (TEM), difFerential scanning calorimetry (DSC), resistivity and magnetothermal analysis. Upon heating, a second precipitation process of the Ni(Hf) phase prior to grain growth wa5 detected by means of both structural analysis and physical property measurements. The measurement results are discussed based on the relationship between microstructure and physical properties.展开更多
The study of evolution is a fundamental pillar in our understanding of the natural world,providing critical insights into how species adapt to their environments through intricate genetic and molecular modifications.T...The study of evolution is a fundamental pillar in our understanding of the natural world,providing critical insights into how species adapt to their environments through intricate genetic and molecular modifications.This research field not only elucidates the origins of biological traits and adaptation mechanisms but also reveals conserved genetic pathways and mutations that underpin biodiversity across different species.展开更多
One major task of studying the formation and evolution of the Moon is to construct a timeline of the important events with precise isotopic ages.Here,we review recent major isotopic geochronological progress in the pa...One major task of studying the formation and evolution of the Moon is to construct a timeline of the important events with precise isotopic ages.Here,we review recent major isotopic geochronological progress in the past decade and the unsolved problems in isotopic geochronology.The Moon probably formed between 4.52 and 4.42 Ga.Recent high-precision whole-rock and mineral Sm-Nd isotopic dating results suggested that ferroan anorthosite and highlands magnesian suite rocks formed contemporarily around 4.37 to 4.33 Ga.Although the major mare basaltic volcanism took place from 3.85 to 2.93 Ga,new geochronological data from lunar meteorites and Chang’e-5 basalts suggested that lunar basaltic volcanism took place as old as up to 4.37 Ga and at least as young as 2.0 Ga,respectively.Impact events older than 3.9 Ga have also been revealed based on U-bearing minerals Pb/Pb ages and Ar-Ar ages and can provide important clues to understand the late heavy bombardment hypothesis.However,the reliable isotopic ages for the important events on the Moon are still far from conclusive,due to lack of pristine samples that directly crystallized from Lunar Magma Ocean and samples from impact melt sheets in large impact basins(e.g.,the South Pole-Aitken basin).In the future,collection and return of pristine samples of ferroan anorthosite and highlands magnesian suite rocks from the farside,cryptomare basalts and late-stage basalts,quartz monzogabbros,granites/felsites,and rocks from impact melt sheets in large impact basins are required for better understanding the formation and evolution of the Moon.展开更多
The deep space and deep sea are imperative frontiers to explore the origin of life,comprehend the Earth,and protect the natural environment.Gases released by the metabolic processes of life leave their marks in the oc...The deep space and deep sea are imperative frontiers to explore the origin of life,comprehend the Earth,and protect the natural environment.Gases released by the metabolic processes of life leave their marks in the ocean dissolved gases and the atmospheric chemical balance.The study of the life evolution on Earth indicates that extraterrestrial oceans and habitable atmospheric environments on exoplanets are the most important elements for traces of extraterrestrial life.In most cutting-edge explorations,the gas molecule is probably one of the most important objects to expand the boundaries of our cognition.展开更多
1 Introduction Genomic islands(GIs)promote co-evolution among different species,which are of significant importance for studying microbial functionality and evolution[1].To effectively identify genomic islands,numerou...1 Introduction Genomic islands(GIs)promote co-evolution among different species,which are of significant importance for studying microbial functionality and evolution[1].To effectively identify genomic islands,numerous algorithms have been developed.These methods detect candidate genomic islands either by recognizing differences in sequence composition between genomic islands and their host genomes or by analyzing multiple genomes through sequence alignment[2].However,it’s important to note that genomic islands are formed through horizontal gene transfer and typically contain functional genes,such as those related to pathogenicity,metabolic regulation,and antibiotic resistance,as well as mobile elements like insertion sequences(IS),integrative and conjugative elements(ICE),mobile genetic elements(MGE),and bacteriophages(phage).In turn,utilizing these mobile elements can aid in the identification of genomic islands.展开更多
文摘The average variational principle was employed in this paper to study the evolution of large-scale and slowly varying Rossby wave packet with basic flow both in barotropic and baroclinic atmospheres. The evolution of the structure of Rossby wave packet with both time and space was studied. The results obtained in this paper are similar to the results of by WKBJ method. In addition, the dispersive process of the wave packet was analysed by taking Gaussian type wave packet as an initial disturbance. The valid time scale for application of wave packet theory in the atmosphere was obtained.
文摘ThiS work was one of the key State-funded projects for natural sciences during the period from 1988-1992 under the joint sponsorship of the CAS,the State Planning Commission,the Institute of Geography and the Yellow River Harnessing Committee under the Ministry of Water Conservancy.The project involves some 140 scientists from 19 research units,such as institutes and universities.Its purpose is to make clear the vicissitudes of environmental evolution and water-and-soil changes in the Yel-
基金National Science Council, Taiwan! under grant !No. NSC-87-2112-M194-005.
文摘Phase evolution and magnetic properties of (Nd_o.95La_0.05)9.5-11Febal.M_2B10.5. where M=Cr, Ti, Nb, V, Mo, Zr, Hf, Ta, Mn or W, melt spun ribbons have been investigated. Almost all the alloy ribbons. except for(Nd_0.95La_0.05)_9.5Fe_78M_2B_10.5(M=Mo and Mn),consist merely two magnetic phases, namely α-Fe and R_2Fe_14B, which display a better combination of _iH_c and magnetic energy product. Remanence (Br) and coercivity (i_H_c) values in the range of 8.0 to 9.1 kG and 9.5 to 18.9 kOe. respectively, can be achieved. Among compositions studied, the Ti and W-substitutions were found to be most effective in increasing the Br and i_H_c, respectively. For a fixed refractory metal substitution, namely, M=C_r, Ti or Nb, an increase in the total rare earth concentration resulted in nanocomposites of small grain sizes and a high volume fraction of the R_2Fe_14B phase, leading to an increase in the magnetic properties.
文摘A nanostructured Hf11Ni89 ribbon sample was prepared by melt-spinning. It was found that the as-quenched sample is composed of a major HfNi5 compound nanophase and an interfacial magnetic Ni(Hf) solid solution phase. The structure evolution of the sample was studied by using X-ray difFraction (XRD), transmission electron microscopy (TEM), difFerential scanning calorimetry (DSC), resistivity and magnetothermal analysis. Upon heating, a second precipitation process of the Ni(Hf) phase prior to grain growth wa5 detected by means of both structural analysis and physical property measurements. The measurement results are discussed based on the relationship between microstructure and physical properties.
文摘The study of evolution is a fundamental pillar in our understanding of the natural world,providing critical insights into how species adapt to their environments through intricate genetic and molecular modifications.This research field not only elucidates the origins of biological traits and adaptation mechanisms but also reveals conserved genetic pathways and mutations that underpin biodiversity across different species.
基金supported by the National Natural Science Foundation (42025302 and 41973061)the preresearch Project on Civil Aerospace Technologies funded by CNSA (D020204)+1 种基金the B-type Strategic Priority Program of the Chinese Academy of Sciences (XDB41000000)by the National Natural Science Foundation of China-Academic Divisions of Chinese Academy of Sciences Frontier Interdisciplinary Research Strategic Research Joint Funding Project (L2224032 and XK2022DXC004).
文摘One major task of studying the formation and evolution of the Moon is to construct a timeline of the important events with precise isotopic ages.Here,we review recent major isotopic geochronological progress in the past decade and the unsolved problems in isotopic geochronology.The Moon probably formed between 4.52 and 4.42 Ga.Recent high-precision whole-rock and mineral Sm-Nd isotopic dating results suggested that ferroan anorthosite and highlands magnesian suite rocks formed contemporarily around 4.37 to 4.33 Ga.Although the major mare basaltic volcanism took place from 3.85 to 2.93 Ga,new geochronological data from lunar meteorites and Chang’e-5 basalts suggested that lunar basaltic volcanism took place as old as up to 4.37 Ga and at least as young as 2.0 Ga,respectively.Impact events older than 3.9 Ga have also been revealed based on U-bearing minerals Pb/Pb ages and Ar-Ar ages and can provide important clues to understand the late heavy bombardment hypothesis.However,the reliable isotopic ages for the important events on the Moon are still far from conclusive,due to lack of pristine samples that directly crystallized from Lunar Magma Ocean and samples from impact melt sheets in large impact basins(e.g.,the South Pole-Aitken basin).In the future,collection and return of pristine samples of ferroan anorthosite and highlands magnesian suite rocks from the farside,cryptomare basalts and late-stage basalts,quartz monzogabbros,granites/felsites,and rocks from impact melt sheets in large impact basins are required for better understanding the formation and evolution of the Moon.
基金supported by the National Key R&D Program of China(2024YFE0201000 and 2023YFF0714700)the National Natural Science Foundation of China(62375262).
文摘The deep space and deep sea are imperative frontiers to explore the origin of life,comprehend the Earth,and protect the natural environment.Gases released by the metabolic processes of life leave their marks in the ocean dissolved gases and the atmospheric chemical balance.The study of the life evolution on Earth indicates that extraterrestrial oceans and habitable atmospheric environments on exoplanets are the most important elements for traces of extraterrestrial life.In most cutting-edge explorations,the gas molecule is probably one of the most important objects to expand the boundaries of our cognition.
基金supported by the National Natural Science Foundation of China(Grant Nos.62172369,62302456)the Special Support Plan for High Level Talents in Zhejiang Province(2021R52019).
文摘1 Introduction Genomic islands(GIs)promote co-evolution among different species,which are of significant importance for studying microbial functionality and evolution[1].To effectively identify genomic islands,numerous algorithms have been developed.These methods detect candidate genomic islands either by recognizing differences in sequence composition between genomic islands and their host genomes or by analyzing multiple genomes through sequence alignment[2].However,it’s important to note that genomic islands are formed through horizontal gene transfer and typically contain functional genes,such as those related to pathogenicity,metabolic regulation,and antibiotic resistance,as well as mobile elements like insertion sequences(IS),integrative and conjugative elements(ICE),mobile genetic elements(MGE),and bacteriophages(phage).In turn,utilizing these mobile elements can aid in the identification of genomic islands.
