We consider the computation of the. Cauchy principal value mtegral by quadrature formulaeof compound type, which are obtained by replacing f by a piecewise defined function F,[;]. The behaviour of the constants m the ...We consider the computation of the. Cauchy principal value mtegral by quadrature formulaeof compound type, which are obtained by replacing f by a piecewise defined function F,[;]. The behaviour of the constants m the estimates where quadrature error) is determined for fixed i and which means that not only the. order, but also the coefficient of the main term of is determined. The behaviour of these error constants is compared -with the corresponding ones obtained for the. method of subtraction of the singularity. As it turns out, these error constants have, in general, the same asymptotic behaviour.展开更多
The relationship between thermal conductivity and properties of mixing particles is required for quantitative study of heat transfer processes in asphalt-based materials. In this paper, we measured the e？ective ther-...The relationship between thermal conductivity and properties of mixing particles is required for quantitative study of heat transfer processes in asphalt-based materials. In this paper, we measured the e？ective ther- mal conductivity of asphalt-based materials with thermal conduction （graphite） and insulation （cenosphere） powders modification. By taking account of the particle shape, volume fraction, the thermal conductivity of filling particles and base asphalt, we present a new differential effective medium formula to predict the thermal conductivity modification in asphalt-based composite. Our theoretical predications are in good agreement with the experiment data. The new model can be applied for predicting the thermal properties of asphalt-based mixture, which is available for most of thermal modification in two-phase composites.展开更多
It has been recently pointed out that the compositions of industrial alloys are originated from cluster-plus-glueatom structure units in solid solutions. Specifically for Ni-based superalloys, after properly grouping ...It has been recently pointed out that the compositions of industrial alloys are originated from cluster-plus-glueatom structure units in solid solutions. Specifically for Ni-based superalloys, after properly grouping the alloying elements into Al, Ni-like（Ni^-）, γ＇-forming Cr-like（Cr^-γ＇） and γ-forming Cr-like（Cr^-γ＇）, the optimal formula for single-crystal superalloys is established [Al–Ni^-12]（AlCr^-γ0：5Cr^-γ1：5）. The Co substitutions for Ni at the shell sites are conducted on the basis of the first-generation single-crystal superalloy AM3, formulated as [Al-Ni2-xCox]（Al1Ti0.25Ta0.25Cr1W0.25Mo0.25）, with x = 1.5, 1.75, 2 and 2.5（the corresponding weight percents of Co are 9.43, 11.0, 12.57 and 15.71, respectively）. The900 ℃ long-term aging follows the Lifshitz–Slyozov–Wagner theory（LSW theory）, and the Co content does not have noticeable influence on the coarsening rate of c0. The microstructure and creep behavior of the four（001） single-crystal alloys are investigated. The creep rupture lifetime is reduced as Co increases. The alloy with the lowest Co（9.43 Co） shows the longest lifetime of about 350 h at 1050 ℃/120 MPa, and all the samples show N-type rafting after creep tests.展开更多
文摘We consider the computation of the. Cauchy principal value mtegral by quadrature formulaeof compound type, which are obtained by replacing f by a piecewise defined function F,[;]. The behaviour of the constants m the estimates where quadrature error) is determined for fixed i and which means that not only the. order, but also the coefficient of the main term of is determined. The behaviour of these error constants is compared -with the corresponding ones obtained for the. method of subtraction of the singularity. As it turns out, these error constants have, in general, the same asymptotic behaviour.
基金supported by the National Natural Science Foundation of China under grants Nos. 50906073 and 50973018
文摘The relationship between thermal conductivity and properties of mixing particles is required for quantitative study of heat transfer processes in asphalt-based materials. In this paper, we measured the e？ective ther- mal conductivity of asphalt-based materials with thermal conduction （graphite） and insulation （cenosphere） powders modification. By taking account of the particle shape, volume fraction, the thermal conductivity of filling particles and base asphalt, we present a new differential effective medium formula to predict the thermal conductivity modification in asphalt-based composite. Our theoretical predications are in good agreement with the experiment data. The new model can be applied for predicting the thermal properties of asphalt-based mixture, which is available for most of thermal modification in two-phase composites.
基金financially supported by the National Key Research and Development Program of China (Grant No. 2016YFB0701401)the National Natural Science Foundation of China (No. 11674045)
文摘It has been recently pointed out that the compositions of industrial alloys are originated from cluster-plus-glueatom structure units in solid solutions. Specifically for Ni-based superalloys, after properly grouping the alloying elements into Al, Ni-like（Ni^-）, γ＇-forming Cr-like（Cr^-γ＇） and γ-forming Cr-like（Cr^-γ＇）, the optimal formula for single-crystal superalloys is established [Al–Ni^-12]（AlCr^-γ0：5Cr^-γ1：5）. The Co substitutions for Ni at the shell sites are conducted on the basis of the first-generation single-crystal superalloy AM3, formulated as [Al-Ni2-xCox]（Al1Ti0.25Ta0.25Cr1W0.25Mo0.25）, with x = 1.5, 1.75, 2 and 2.5（the corresponding weight percents of Co are 9.43, 11.0, 12.57 and 15.71, respectively）. The900 ℃ long-term aging follows the Lifshitz–Slyozov–Wagner theory（LSW theory）, and the Co content does not have noticeable influence on the coarsening rate of c0. The microstructure and creep behavior of the four（001） single-crystal alloys are investigated. The creep rupture lifetime is reduced as Co increases. The alloy with the lowest Co（9.43 Co） shows the longest lifetime of about 350 h at 1050 ℃/120 MPa, and all the samples show N-type rafting after creep tests.
