Gossypium hirsutum,the most widely planted cotton species,its evolution has long been an unsolved puzzle because of its hybrid origin from D-genome and A-genome species.To better understand the genetic component of co...Gossypium hirsutum,the most widely planted cotton species,its evolution has long been an unsolved puzzle because of its hybrid origin from D-genome and A-genome species.To better understand the genetic component of cotton,Huang et al.recently sequenced and assembled the first A1-genome G.herbaceum,and updated the A2-genome G.arboreum and(AD)1-genome G.hirsutum.On the basis of the three reference genomes,they resolved existing controversial concepts and provided novel evolutionary insights surrounding the A-genome.展开更多
The planning aspects of landscape architecture in the United States including its origin, planning principles and landscape assessment techniques developed by "METLAND" system are introduced in this paper. T...The planning aspects of landscape architecture in the United States including its origin, planning principles and landscape assessment techniques developed by "METLAND" system are introduced in this paper. Thereafter, the development of greenway in the USA and its actualities are discussed with examples, and significant greenway proposals for America in recent years are made.展开更多
Running safety assessment and tracking irregularity parametric sensitivity analysis of high-speed maglev train-bridge system are of great concern,especially need perfect refinement models in which all properties can b...Running safety assessment and tracking irregularity parametric sensitivity analysis of high-speed maglev train-bridge system are of great concern,especially need perfect refinement models in which all properties can be well characterized based on various stochastic excitations.A three-dimensional refined spatial random vibration analysis model of high-speed maglev train-bridge coupled system is established in this paper,in which multi-source uncertainty excitation can be considered simultaneously,and the probability density evolution method(PDEM)is adopted to reveal the system-specific uncertainty dynamic characteristic.The motion equation of the maglev vehicle model is composed of multi-rigid bodies with a total 210-degrees of freedom for each vehicle,and a refined electromagnetic force-air gap model is used to account for the interaction and coupling effect between the moving train and track beam bridges,which are directly established by using finite element method.The model is proven to be applicable by comparing with Monte Carlo simulation.By applying the proposed stochastic framework to the high maglev line,the random dynamic responses of maglev vehicles running on the bridges are studied for running safety and stability assessment.Moreover,the effects of track irregularity wavelength range under different amplitude and running speeds on the coupled system are investigated.The results show that the augmentation of train speed will move backward the sensitive wavelength interval,and track irregularity amplitude influences the response remarkably in the sensitive interval.展开更多
Gezhouba hydroproject was impounded and put into operation in 1981. In order to analyse the impact on the downstream river course, Jingjiang Hydrologic and Water Resources Survey Bureau of Changjiang Water Resources C...Gezhouba hydroproject was impounded and put into operation in 1981. In order to analyse the impact on the downstream river course, Jingjiang Hydrologic and Water Resources Survey Bureau of Changjiang Water Resources Commission has conducted prototype observation on the Yichang-Chenglingji river stretch. On basis of the observed data, the change in river regime and scour-sedimentation evolution and water surface profile below the dam are analysed systematically. The results show that the scouring of downstream river course mainly stretches from Yichang to Ouchikou, mainly occurring in 1980～1987; the scourring mainly takes place in the river channel and the water surface profile drops significantly in dry season,but not quite in high flood season.展开更多
Random dynamic responses caused by the uncertainty of structural parameters of the coupled train-ballasted track-subgrade system under train loading can pose safety concerns to the train operation.This paper introduce...Random dynamic responses caused by the uncertainty of structural parameters of the coupled train-ballasted track-subgrade system under train loading can pose safety concerns to the train operation.This paper introduced a computational model for analyzing probabilistic dynamic responses of three-dimensional(3D)coupled train-ballasted track-subgrade system(TBTSS),where the coupling effects of uncertain rail irregularities,stiffness and damping properties of ballast and subgrade layers were simultaneously considered.The number theoretical method(NTM)was employed to design discrete points for the multi-dimensional stochastic parameters.The time-histories of stochastic dynamic vibrations of the TBSS with systematically uncertain structural parameters were calculated accurately and efficiently by employing the probability density evolution method(PDEM).The model-predicted results were consistent with those by the Monte Carlo simulation method.A sensitivity study was performed to assess the relative importance of those uncertain structural parameters,based on which a case study was presented to explore the stochastic probability evolution mechanism of such train-ballasted track-subgrade system.展开更多
The photo absorbing, photo transmitting and photoluminescence performances of WiO2 photocatalysts compounded with V2O5 or WO3 were investigated by UV-Vis spectra, transmitting spectra, and PL spectra, respectively. Th...The photo absorbing, photo transmitting and photoluminescence performances of WiO2 photocatalysts compounded with V2O5 or WO3 were investigated by UV-Vis spectra, transmitting spectra, and PL spectra, respectively. The energy band structures of TiO2 photocatalysts were analyzed. The photocatalytic activities of the TiO2 photocatalysts were investigated by splitting of water for 02 evolution. The results indicate that the band gaps of WO3 and V205 are about 2.8 and 2.14 eV, respectively, and the band gap of rutile TiO2 is about 3.08 eV. Speeds of water splitting for 2%WO3-TiO2 and 8%V2O5-TiO2 photocatalysts are 420 and 110 μmol/（L.h）, respectively, under UV light irradiation. V2O5 and WO3 compounded with suitable concentration can improve the photocatalytic activity of TiO2 with Fe3＋ as electron acceptor.展开更多
The results of characteristic comparison and principal component analysis showed that the major .characteristics of sesame varieties in Henan province were improved in the past decades. The sesame breeding works in th...The results of characteristic comparison and principal component analysis showed that the major .characteristics of sesame varieties in Henan province were improved in the past decades. The sesame breeding works in the province were focused on the collection and the screening of the native germplasms from 1950 to 1969 and the mean values of the variety characteristics were the lowest. In 1970s,the pedigree breeding was mainly conducted,which resulted in the release of varieties of various types with better traits. During 1980s,the hybridization breeding was carried out dominantly with the varieties possessing fine traits. Since 1990,there were no better varieties released. To make new progresses,it is essential to renew the breeding method and at the same time to introduce and create special germplasms to widen the genetic background.展开更多
Tibet Plateau has uplifted greatly in the Late Cenozoic era (Li Jijun et al., 1979; Sun Honglie, 1996; Shi Yafeng et al., 1998). The uplift will unquestionably influence the environment and climate of the plateau in t...Tibet Plateau has uplifted greatly in the Late Cenozoic era (Li Jijun et al., 1979; Sun Honglie, 1996; Shi Yafeng et al., 1998). The uplift will unquestionably influence the environment and climate of the plateau in the same time (such as resulting in the decrease of temperature) and leave some footprint on the contemporary sediments on or around the plateau. So, there must be some persistence component in the environmental and climatic evolution reflected by the geochemical information in the contemporary sediments. TS95, namely Tianshuihai Lake core is at the south frank of West Kunlun Mountain of Tibet Plateau and is suitable for the investigation of the persistence component. Using R/S analysis, Zhou Houyun et al. (1999) have previously calculated the Hurst index H of the three ferric indexes, FeO, Fe\-2O\-3 and ratio of FeO/ Fe\-2O\-3, from TS95. It is found that all these indexes satisfy Hurst law and they all are greater than 0 5, which means that there are some long run dependencies\|persistence component in the climatic and environmental evolution around Tianshuihai Lake area. This is in accordance with previous work by Yu Suhua et al. (1996). In this paper, the authors use the same method to do some R/S analysis on the other two climatic proxies of TS95, δ 13 C and δ 18 O, which are more suitable than the three ferric indexes to be climatic and environmental proxies. It is found that both the δ 13 C and δ 18 O satisfy Hurst law very well with H δ 13 C =0 875 and H δ 18 O =894, which suggests stronger persistence than the three ferric indexes.展开更多
MicroRNA（miRNA） is a class of important regulating non-coding small molecular RNA. The gma-MIR166 gene family consists of 21 members and their expression patterns diversify widely. It is important to analyze the evo...MicroRNA（miRNA） is a class of important regulating non-coding small molecular RNA. The gma-MIR166 gene family consists of 21 members and their expression patterns diversify widely. It is important to analyze the evolution of gma-MIR166 gene family in order to understand the evolutionary mechanisms of miRNAs in soybean. In this study, we implemented soybean wide genome block analysis, the molecular phylogeny of gma-MIR166 and block analysis of gma-MIR166 family. The results showed that both chromosome big segmental duplications and tandem duplications were main reasons contributed to the expanding of gmaMIR166 gene family. These findings suggested that gma-MIR166 gene family might originate from one or two ancient miRNA genes. The results of research provided a support for evolutionary study of miRNAs in soybean and related species in Fabaceae.展开更多
The finite element model is established according to the experimental results,and then the experimental results are verified by simulation calculation.In terms of the combination of finite element analysis and experim...The finite element model is established according to the experimental results,and then the experimental results are verified by simulation calculation.In terms of the combination of finite element analysis and experiment,the effect of particle size of CuO and SnO_(2) on the stress,strain and microstructure of AgCuOSnO_(2) composite during hot extrusion was studied.The results illustrate that with the decrease of particle size,the dispersion of the second phase increases gradually,while the possibility of“tail shrinkage”of the billet decreases continuously;cubic CuO will evolve to fibrosis,and the degree of fibrosis will increase with the decrease of the particle size and ring clusters.Specifically,the degree of fibrosis at the middle end of the billet is higher than that at the front end,the degree of fibrosis at the front end is higher than that at the back end,and the degree of fibrosis on the surface is higher than that in the core;part of CuO fibers will bend,and the degree of buckling strength is positively correlated with the size of particles and their annular clusters.Additionally,there is fiber CuO in the front and back end of the billet that are inconsistent with the extrusion direction,and the degree of difference was negatively correlated with the particle size.展开更多
Citrus tristeza virus （CTV）, the most devastating viral pathogen in citrus, causes tremendous economic losses to citrus industry worldwide. The CTV isolates exhibit variable pathogenicities on their hosts indicating...Citrus tristeza virus （CTV）, the most devastating viral pathogen in citrus, causes tremendous economic losses to citrus industry worldwide. The CTV isolates exhibit variable pathogenicities on their hosts indicating a mixed population of the CTV in nature. Several fragments within the CTV genome have been used for studying the genetic diversity of the CTV, however, the best region for rapid the CTV strain differentiation is still absent at present. In present study, a systemic analysis was carried out to evaluate the best region within the CTV genome for rapid CTV strain differentiation. Results of our study showed that the major coat protein （CP） coding region was the best region for this purpose. Using pair-wise distance frequency distribution plot, a reasonable genetic distance cut-off value was set for the CTV CP gene for the CTV strain differentiation. Using this criterion, eight CTV strains, including seven well characterized and a new strain, were successfully differentiated using 537 CTV isolates reported from 38 countries. The global strain distribution pattern was then determined and discussed. Our results also provided a new insight into the evolution and spreading of the virus, as well as the information for developing proper disease management strategy.展开更多
The development of Chinese space science and technology plays a great role in promoting the researches in the field of the origin of life.With the multidisciplinary cooperation,there are fruitful achievements in this ...The development of Chinese space science and technology plays a great role in promoting the researches in the field of the origin of life.With the multidisciplinary cooperation,there are fruitful achievements in this research field obtained over the past two years.This report summarizes the major progress of the basic researches about the origin of life in China during 2018–2020.展开更多
文摘Gossypium hirsutum,the most widely planted cotton species,its evolution has long been an unsolved puzzle because of its hybrid origin from D-genome and A-genome species.To better understand the genetic component of cotton,Huang et al.recently sequenced and assembled the first A1-genome G.herbaceum,and updated the A2-genome G.arboreum and(AD)1-genome G.hirsutum.On the basis of the three reference genomes,they resolved existing controversial concepts and provided novel evolutionary insights surrounding the A-genome.
文摘The planning aspects of landscape architecture in the United States including its origin, planning principles and landscape assessment techniques developed by "METLAND" system are introduced in this paper. Thereafter, the development of greenway in the USA and its actualities are discussed with examples, and significant greenway proposals for America in recent years are made.
基金Project(2023YFB4302500)supported by the National Key R&D Program of ChinaProject(52078485)supported by the National Natural Science Foundation of ChinaProjects(2021-Major-16,2021-Special-08)supported by the Science and Technology Research and Development Program Project of China Railway Group Limited。
文摘Running safety assessment and tracking irregularity parametric sensitivity analysis of high-speed maglev train-bridge system are of great concern,especially need perfect refinement models in which all properties can be well characterized based on various stochastic excitations.A three-dimensional refined spatial random vibration analysis model of high-speed maglev train-bridge coupled system is established in this paper,in which multi-source uncertainty excitation can be considered simultaneously,and the probability density evolution method(PDEM)is adopted to reveal the system-specific uncertainty dynamic characteristic.The motion equation of the maglev vehicle model is composed of multi-rigid bodies with a total 210-degrees of freedom for each vehicle,and a refined electromagnetic force-air gap model is used to account for the interaction and coupling effect between the moving train and track beam bridges,which are directly established by using finite element method.The model is proven to be applicable by comparing with Monte Carlo simulation.By applying the proposed stochastic framework to the high maglev line,the random dynamic responses of maglev vehicles running on the bridges are studied for running safety and stability assessment.Moreover,the effects of track irregularity wavelength range under different amplitude and running speeds on the coupled system are investigated.The results show that the augmentation of train speed will move backward the sensitive wavelength interval,and track irregularity amplitude influences the response remarkably in the sensitive interval.
文摘Gezhouba hydroproject was impounded and put into operation in 1981. In order to analyse the impact on the downstream river course, Jingjiang Hydrologic and Water Resources Survey Bureau of Changjiang Water Resources Commission has conducted prototype observation on the Yichang-Chenglingji river stretch. On basis of the observed data, the change in river regime and scour-sedimentation evolution and water surface profile below the dam are analysed systematically. The results show that the scouring of downstream river course mainly stretches from Yichang to Ouchikou, mainly occurring in 1980～1987; the scourring mainly takes place in the river channel and the water surface profile drops significantly in dry season,but not quite in high flood season.
基金Projects(51708558,51878673,U1734208,52078485,U1934217,U1934209)supported by the National Natural Science Foundation of ChinaProject(2020JJ5740)supported by the Natural Science Foundation of Hunan Province,China+1 种基金Project(KF2020-03)supported by the Key Open Fund of State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures,ChinaProject(2020-Special-02)supported by the Science and Technology Research and Development Program of China Railway Group Limited。
文摘Random dynamic responses caused by the uncertainty of structural parameters of the coupled train-ballasted track-subgrade system under train loading can pose safety concerns to the train operation.This paper introduced a computational model for analyzing probabilistic dynamic responses of three-dimensional(3D)coupled train-ballasted track-subgrade system(TBTSS),where the coupling effects of uncertain rail irregularities,stiffness and damping properties of ballast and subgrade layers were simultaneously considered.The number theoretical method(NTM)was employed to design discrete points for the multi-dimensional stochastic parameters.The time-histories of stochastic dynamic vibrations of the TBSS with systematically uncertain structural parameters were calculated accurately and efficiently by employing the probability density evolution method(PDEM).The model-predicted results were consistent with those by the Monte Carlo simulation method.A sensitivity study was performed to assess the relative importance of those uncertain structural parameters,based on which a case study was presented to explore the stochastic probability evolution mechanism of such train-ballasted track-subgrade system.
基金Project(11JJ5010) supported by the Natural Science Foundation of Hunan Province, ChinaProject(2011RS4069) supported by the Planned Science and Technology Program of Hunan Province, ChinaProject supported by the Postdoctoral Science Foundation of Central South University,China
文摘The photo absorbing, photo transmitting and photoluminescence performances of WiO2 photocatalysts compounded with V2O5 or WO3 were investigated by UV-Vis spectra, transmitting spectra, and PL spectra, respectively. The energy band structures of TiO2 photocatalysts were analyzed. The photocatalytic activities of the TiO2 photocatalysts were investigated by splitting of water for 02 evolution. The results indicate that the band gaps of WO3 and V205 are about 2.8 and 2.14 eV, respectively, and the band gap of rutile TiO2 is about 3.08 eV. Speeds of water splitting for 2%WO3-TiO2 and 8%V2O5-TiO2 photocatalysts are 420 and 110 μmol/（L.h）, respectively, under UV light irradiation. V2O5 and WO3 compounded with suitable concentration can improve the photocatalytic activity of TiO2 with Fe3＋ as electron acceptor.
文摘The results of characteristic comparison and principal component analysis showed that the major .characteristics of sesame varieties in Henan province were improved in the past decades. The sesame breeding works in the province were focused on the collection and the screening of the native germplasms from 1950 to 1969 and the mean values of the variety characteristics were the lowest. In 1970s,the pedigree breeding was mainly conducted,which resulted in the release of varieties of various types with better traits. During 1980s,the hybridization breeding was carried out dominantly with the varieties possessing fine traits. Since 1990,there were no better varieties released. To make new progresses,it is essential to renew the breeding method and at the same time to introduce and create special germplasms to widen the genetic background.
文摘Tibet Plateau has uplifted greatly in the Late Cenozoic era (Li Jijun et al., 1979; Sun Honglie, 1996; Shi Yafeng et al., 1998). The uplift will unquestionably influence the environment and climate of the plateau in the same time (such as resulting in the decrease of temperature) and leave some footprint on the contemporary sediments on or around the plateau. So, there must be some persistence component in the environmental and climatic evolution reflected by the geochemical information in the contemporary sediments. TS95, namely Tianshuihai Lake core is at the south frank of West Kunlun Mountain of Tibet Plateau and is suitable for the investigation of the persistence component. Using R/S analysis, Zhou Houyun et al. (1999) have previously calculated the Hurst index H of the three ferric indexes, FeO, Fe\-2O\-3 and ratio of FeO/ Fe\-2O\-3, from TS95. It is found that all these indexes satisfy Hurst law and they all are greater than 0 5, which means that there are some long run dependencies\|persistence component in the climatic and environmental evolution around Tianshuihai Lake area. This is in accordance with previous work by Yu Suhua et al. (1996). In this paper, the authors use the same method to do some R/S analysis on the other two climatic proxies of TS95, δ 13 C and δ 18 O, which are more suitable than the three ferric indexes to be climatic and environmental proxies. It is found that both the δ 13 C and δ 18 O satisfy Hurst law very well with H δ 13 C =0 875 and H δ 18 O =894, which suggests stronger persistence than the three ferric indexes.
基金Supported by Heilongjiang Postdoctoral Fund(LBH-Z12045)Northeast Agricultural University Innovation Foundation For Postgraduate(yjscx14053)
文摘MicroRNA（miRNA） is a class of important regulating non-coding small molecular RNA. The gma-MIR166 gene family consists of 21 members and their expression patterns diversify widely. It is important to analyze the evolution of gma-MIR166 gene family in order to understand the evolutionary mechanisms of miRNAs in soybean. In this study, we implemented soybean wide genome block analysis, the molecular phylogeny of gma-MIR166 and block analysis of gma-MIR166 family. The results showed that both chromosome big segmental duplications and tandem duplications were main reasons contributed to the expanding of gmaMIR166 gene family. These findings suggested that gma-MIR166 gene family might originate from one or two ancient miRNA genes. The results of research provided a support for evolutionary study of miRNAs in soybean and related species in Fabaceae.
基金Project(2017FA027)supported by the Key Project of Science and Technology of Yunnan Province,China。
文摘The finite element model is established according to the experimental results,and then the experimental results are verified by simulation calculation.In terms of the combination of finite element analysis and experiment,the effect of particle size of CuO and SnO_(2) on the stress,strain and microstructure of AgCuOSnO_(2) composite during hot extrusion was studied.The results illustrate that with the decrease of particle size,the dispersion of the second phase increases gradually,while the possibility of“tail shrinkage”of the billet decreases continuously;cubic CuO will evolve to fibrosis,and the degree of fibrosis will increase with the decrease of the particle size and ring clusters.Specifically,the degree of fibrosis at the middle end of the billet is higher than that at the front end,the degree of fibrosis at the front end is higher than that at the back end,and the degree of fibrosis on the surface is higher than that in the core;part of CuO fibers will bend,and the degree of buckling strength is positively correlated with the size of particles and their annular clusters.Additionally,there is fiber CuO in the front and back end of the billet that are inconsistent with the extrusion direction,and the degree of difference was negatively correlated with the particle size.
基金Supported by the National Natural Science Foundation of China (31101417 31101415)+1 种基金Zhejiang Provincial Natural Science Foundation of China (Y3110175 Y3110277)
文摘Citrus tristeza virus （CTV）, the most devastating viral pathogen in citrus, causes tremendous economic losses to citrus industry worldwide. The CTV isolates exhibit variable pathogenicities on their hosts indicating a mixed population of the CTV in nature. Several fragments within the CTV genome have been used for studying the genetic diversity of the CTV, however, the best region for rapid the CTV strain differentiation is still absent at present. In present study, a systemic analysis was carried out to evaluate the best region within the CTV genome for rapid CTV strain differentiation. Results of our study showed that the major coat protein （CP） coding region was the best region for this purpose. Using pair-wise distance frequency distribution plot, a reasonable genetic distance cut-off value was set for the CTV CP gene for the CTV strain differentiation. Using this criterion, eight CTV strains, including seven well characterized and a new strain, were successfully differentiated using 537 CTV isolates reported from 38 countries. The global strain distribution pattern was then determined and discussed. Our results also provided a new insight into the evolution and spreading of the virus, as well as the information for developing proper disease management strategy.
文摘The development of Chinese space science and technology plays a great role in promoting the researches in the field of the origin of life.With the multidisciplinary cooperation,there are fruitful achievements in this research field obtained over the past two years.This report summarizes the major progress of the basic researches about the origin of life in China during 2018–2020.
