Microstructure observation and dynamic mechanical analysis were carried out to investigate the precipitation and responding damping behaviors of AZ31 magnesium alloy. All the strain amplitude-dependent damping curves ...Microstructure observation and dynamic mechanical analysis were carried out to investigate the precipitation and responding damping behaviors of AZ31 magnesium alloy. All the strain amplitude-dependent damping curves of the aged alloys are located between the curves of solutionized and as-cast alloys, although they have different critical strain amplitudes. The G-L theory is employed to explain the damping mechanism involving the interaction between the dislocation and the precipitated phase. In addition, a damping peak is observed at temperatures close to 330 ℃ for AZ31 magnesium alloy, which is related to the β-MglTA112 phase dissolution.展开更多
AZ31 alloy sheet fabricated by rolling was processed by friction stir processing(FSP) with different passes. The effect of FSP on the microstructure and damping capacity of AZ31 alloy sheet was discussed. The fine and...AZ31 alloy sheet fabricated by rolling was processed by friction stir processing(FSP) with different passes. The effect of FSP on the microstructure and damping capacity of AZ31 alloy sheet was discussed. The fine and equiaxed grains were obtained in the stirred zone(SZ) for FSPed samples from 1 pass to 3 passes with the average grain size of 10.6, 10.4 and 13.6 μm, respectively. The damping peak P_1 was presented on the curves of temperature-dependent damping capacity for FSPed samples. The damping peak P_2 was restrained after FSP and the damping peak P_1 was a relaxation process. The FSPed samples(2-pass FSP and 3-pass FSP) obtained high damping capacity. The best damping valuesQ_0^(-1)(ε=10_(-4)) and damping values Q_H^(-1)(ε=10^(-3)) of the sample subjected to 3-pass FSP(0.0131 and 0.0496) increased by 33.7% and 157.0%, respectively.展开更多
为提高遥感影像检索的精度,提出一种基于快速查找密度峰值聚类(Fast Search and Find of Density Peaks,FSFDP)的改进视觉词袋(Bag of Visual word,BoV)模型,该方法充分利用FSFDP聚类算法分类精度高和聚类参数易于选择等优点,增强BoV模...为提高遥感影像检索的精度,提出一种基于快速查找密度峰值聚类(Fast Search and Find of Density Peaks,FSFDP)的改进视觉词袋(Bag of Visual word,BoV)模型,该方法充分利用FSFDP聚类算法分类精度高和聚类参数易于选择等优点,增强BoV模型特征量化的稳定性和可靠性。实验表明,与经典BoV模型相比,FSFDP-BoV模型能够得到更高的检索精度。展开更多
The shape and shift of Raman peak of solid organics prove to be capable of revealing atomic and molecular level vibration information of aromatic ring structure and its relationship with sample maturation. Raman "...The shape and shift of Raman peak of solid organics prove to be capable of revealing atomic and molecular level vibration information of aromatic ring structure and its relationship with sample maturation. Raman "D" peaks and "G" peaks of a series of continuously maturated coal samples were measured, and the inter-peak intervals (G-D) and peak height ratios (Dh/Gh) were derived and correlated with the vitrinite reflectance (vRo%) of standard coal samples. As a result, two formulae were established by using the two Raman indices for calculation of Raman reflectance (RmcRo%), which is equivalent to vitrinite reflectance. The formula for calculating Raman reflectance indicative of organic maturation using Raman shift inter-peak interval (G-D) is RmcRo%=0.0537d(G-D)-11.21, which is mainly applicable to matured to highly matured carbonized samples of solid organics; The formula for calculating Raman reflectance indicative of organic maturation using Raman peak height ratio (Dh/Gh) is RmcRo%=1.1659h (Dh/Gh)+2.7588, which is mainly applicable to carbonized samples of solid organics that are over matured or going to be turned into granulated graphite. Preliminary applications indicate that Raman reflectance "RmcRo%" calculated based on results of Raman spectral analysis of solid organics can be used to characterize sample maturation at molecular level, so enjoying extensive prospects in geological applications.展开更多
基金supported by National Natural Science Foundation of China (Nos.50671083 and 50571081)Aeronautical Science Foundation of China (No.04G53042)Natural Science Foundation of the Shaanxi Province(No.2007E101)
文摘Microstructure observation and dynamic mechanical analysis were carried out to investigate the precipitation and responding damping behaviors of AZ31 magnesium alloy. All the strain amplitude-dependent damping curves of the aged alloys are located between the curves of solutionized and as-cast alloys, although they have different critical strain amplitudes. The G-L theory is employed to explain the damping mechanism involving the interaction between the dislocation and the precipitated phase. In addition, a damping peak is observed at temperatures close to 330 ℃ for AZ31 magnesium alloy, which is related to the β-MglTA112 phase dissolution.
基金Project(51301077)supported by the National Natural Science Foundation,ChinaProject(BK20130470)supported by the Natural Science Foundation of Jiangsu Province,ChinaProject supported by Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘AZ31 alloy sheet fabricated by rolling was processed by friction stir processing(FSP) with different passes. The effect of FSP on the microstructure and damping capacity of AZ31 alloy sheet was discussed. The fine and equiaxed grains were obtained in the stirred zone(SZ) for FSPed samples from 1 pass to 3 passes with the average grain size of 10.6, 10.4 and 13.6 μm, respectively. The damping peak P_1 was presented on the curves of temperature-dependent damping capacity for FSPed samples. The damping peak P_2 was restrained after FSP and the damping peak P_1 was a relaxation process. The FSPed samples(2-pass FSP and 3-pass FSP) obtained high damping capacity. The best damping valuesQ_0^(-1)(ε=10_(-4)) and damping values Q_H^(-1)(ε=10^(-3)) of the sample subjected to 3-pass FSP(0.0131 and 0.0496) increased by 33.7% and 157.0%, respectively.
文摘为提高遥感影像检索的精度,提出一种基于快速查找密度峰值聚类(Fast Search and Find of Density Peaks,FSFDP)的改进视觉词袋(Bag of Visual word,BoV)模型,该方法充分利用FSFDP聚类算法分类精度高和聚类参数易于选择等优点,增强BoV模型特征量化的稳定性和可靠性。实验表明,与经典BoV模型相比,FSFDP-BoV模型能够得到更高的检索精度。
基金supported by the National Basic Research Program of China (2012CB214705)the National Natural Science Foundation of China (41072095)+1 种基金the State Scientific Brainstorm Program (2011ZX05008-002)the Knowledge Innovation Program of the Chinese Academy of Sciences (KZCX2-YW-Q05-03 and KZCX2-YW-Q05-06)
文摘The shape and shift of Raman peak of solid organics prove to be capable of revealing atomic and molecular level vibration information of aromatic ring structure and its relationship with sample maturation. Raman "D" peaks and "G" peaks of a series of continuously maturated coal samples were measured, and the inter-peak intervals (G-D) and peak height ratios (Dh/Gh) were derived and correlated with the vitrinite reflectance (vRo%) of standard coal samples. As a result, two formulae were established by using the two Raman indices for calculation of Raman reflectance (RmcRo%), which is equivalent to vitrinite reflectance. The formula for calculating Raman reflectance indicative of organic maturation using Raman shift inter-peak interval (G-D) is RmcRo%=0.0537d(G-D)-11.21, which is mainly applicable to matured to highly matured carbonized samples of solid organics; The formula for calculating Raman reflectance indicative of organic maturation using Raman peak height ratio (Dh/Gh) is RmcRo%=1.1659h (Dh/Gh)+2.7588, which is mainly applicable to carbonized samples of solid organics that are over matured or going to be turned into granulated graphite. Preliminary applications indicate that Raman reflectance "RmcRo%" calculated based on results of Raman spectral analysis of solid organics can be used to characterize sample maturation at molecular level, so enjoying extensive prospects in geological applications.
