Finite element(FEM)analysis was used to systematically evaluate the inhomogeneity of deformation in cylindrical samples with various sample-anvil friction coefficients,m.It was found that the level of friction strongl...Finite element(FEM)analysis was used to systematically evaluate the inhomogeneity of deformation in cylindrical samples with various sample-anvil friction coefficients,m.It was found that the level of friction strongly influences the deformation homogeneity,which increases significantly with the friction coefficient although the overall geometry of the samples almost remains the same when m >0.4.The position,at which the effective strain along the maximum radial direction in a compressed sample is equal to the equivalent strain of the sample,does not vary greatly with respect to both equivalent strain of the sample and m.Hardness measurements of compressed cylindrical 5056B Al alloy samples revealed a change of effective strain distribution similar to that revealed by FEM analysis.There exists a quantitative relationship between the hardness and the effective strain if no recrystallization or recovery occurs during the compression process.展开更多
The observation data from ground surface meteorological stations is an important basis on which climate change research is carried out, while the homogenization of the data is necessary for improving the quality and h...The observation data from ground surface meteorological stations is an important basis on which climate change research is carried out, while the homogenization of the data is necessary for improving the quality and homogeneity of the time series. This paper reviews recent advances in the techniques of identifying and adjusting inhomogeneity in climate series. We briefly introduce the results of applying two commonly accepted and well-developed methods (RHtest and MASH) to surface climate observations such as temperature and wind speed in China. We then summarize current progress and problems in this field, and propose ideas for future studies in China. Along with collecting more detailed metadata, more research on homogenization technology should be done in the future. On the basis of comparing and evaluating advantages and disadvantages of different homogenization methods, the homogenized climate data series of the last hundred years should be rebuilt.展开更多
Numerous articles have examined archival weather observations and attributed climate changes on time scales ranging from centuries to decades and in one case even days to human activity. This article gives examples sh...Numerous articles have examined archival weather observations and attributed climate changes on time scales ranging from centuries to decades and in one case even days to human activity. This article gives examples showing how climate variability and sudden changes in instruments affect trend determination. In particular, surface temperature and water vapor pressure trends in North America during 1948-2010 are discussed. Over 1/4 billion hourly observations taken at 309 stations, were first carefully examined for inhomogeneities. Positive and negative steps, for both temperature and water vapor pressure were found to not be evenly distributed in time. Inclusion of such data in a trend analysis would overstate decadal changes in temperature and water vapor. Time series free of such discontinuities show a statistically significant warming has primarily affected the western Arctic, Canadian prairies and the Midwestern U.S. during winter. Increases in water vapor pressure are most pronounced in summer in the eastern U.S. The decadal water vapor pressure trends are somewhat smaller than found in other studies that examined data for far shorter time periods. The claim of a change in the DTR （diurnal temperature range） during the 3 day flight ban following Sept. 11, 2011, is not substantiated. The observed change in the DTR was likely caused by a reduction in cloudiness during the flight ban.展开更多
The microscopic approach is developed for obtaining of the free energy of a superconductor based on direct calculation of the vacuum amplitude.The free energy functional of the spatially inhomogeneous superconductor i...The microscopic approach is developed for obtaining of the free energy of a superconductor based on direct calculation of the vacuum amplitude.The free energy functional of the spatially inhomogeneous superconductor in a magnetic field is obtained with help of the developed approach.The obtained functional is generalization of GinzburgLandau functionals for any temperature,for arbitrary spatial variations of the order parameter and for the nonlocality of a magnetic response and the order parameter.Moreover,the nonlocality of the magnetic response is the consequence of order parameter's nonlocality.The extremals of this functional are considered in the explicit form in the low-and high-temperature limit at the condition of slowness of spatial variations of the order parameter.展开更多
基金Project(2016JJ1016) supported by the Science Fund for Distinguished Young Scholars of Hunan Province,ChinaProject(201301G0105337290) supported by the Program of Innovation and Entrepreneur Team Introduced by Guangdong Province,China
文摘Finite element(FEM)analysis was used to systematically evaluate the inhomogeneity of deformation in cylindrical samples with various sample-anvil friction coefficients,m.It was found that the level of friction strongly influences the deformation homogeneity,which increases significantly with the friction coefficient although the overall geometry of the samples almost remains the same when m >0.4.The position,at which the effective strain along the maximum radial direction in a compressed sample is equal to the equivalent strain of the sample,does not vary greatly with respect to both equivalent strain of the sample and m.Hardness measurements of compressed cylindrical 5056B Al alloy samples revealed a change of effective strain distribution similar to that revealed by FEM analysis.There exists a quantitative relationship between the hardness and the effective strain if no recrystallization or recovery occurs during the compression process.
基金supported by the National Program on Key Basic Research Project (No. 2010CB951602, 2009CB421401)National Science and Technology Ministry (No. 2008BAK50B07)+1 种基金China Special Fund for Meteorological Research in the Public Interest (No. 200906041-052)the Project of National Natural Science Foundation of China (No. 40805060)
文摘The observation data from ground surface meteorological stations is an important basis on which climate change research is carried out, while the homogenization of the data is necessary for improving the quality and homogeneity of the time series. This paper reviews recent advances in the techniques of identifying and adjusting inhomogeneity in climate series. We briefly introduce the results of applying two commonly accepted and well-developed methods (RHtest and MASH) to surface climate observations such as temperature and wind speed in China. We then summarize current progress and problems in this field, and propose ideas for future studies in China. Along with collecting more detailed metadata, more research on homogenization technology should be done in the future. On the basis of comparing and evaluating advantages and disadvantages of different homogenization methods, the homogenized climate data series of the last hundred years should be rebuilt.
文摘Numerous articles have examined archival weather observations and attributed climate changes on time scales ranging from centuries to decades and in one case even days to human activity. This article gives examples showing how climate variability and sudden changes in instruments affect trend determination. In particular, surface temperature and water vapor pressure trends in North America during 1948-2010 are discussed. Over 1/4 billion hourly observations taken at 309 stations, were first carefully examined for inhomogeneities. Positive and negative steps, for both temperature and water vapor pressure were found to not be evenly distributed in time. Inclusion of such data in a trend analysis would overstate decadal changes in temperature and water vapor. Time series free of such discontinuities show a statistically significant warming has primarily affected the western Arctic, Canadian prairies and the Midwestern U.S. during winter. Increases in water vapor pressure are most pronounced in summer in the eastern U.S. The decadal water vapor pressure trends are somewhat smaller than found in other studies that examined data for far shorter time periods. The claim of a change in the DTR （diurnal temperature range） during the 3 day flight ban following Sept. 11, 2011, is not substantiated. The observed change in the DTR was likely caused by a reduction in cloudiness during the flight ban.
文摘The microscopic approach is developed for obtaining of the free energy of a superconductor based on direct calculation of the vacuum amplitude.The free energy functional of the spatially inhomogeneous superconductor in a magnetic field is obtained with help of the developed approach.The obtained functional is generalization of GinzburgLandau functionals for any temperature,for arbitrary spatial variations of the order parameter and for the nonlocality of a magnetic response and the order parameter.Moreover,the nonlocality of the magnetic response is the consequence of order parameter's nonlocality.The extremals of this functional are considered in the explicit form in the low-and high-temperature limit at the condition of slowness of spatial variations of the order parameter.
