淬火-配分(Quenching and Partitioning,Q&P)钢由于具有优异的综合性能而备受关注。本文设计了一步等温和二步等温处理工艺,通过改变淬火温度和等温温度获得了不同含量一次马氏体(PM)、残余奥氏体(RA)、二次马氏体(FM)及贝氏体(BF)...淬火-配分(Quenching and Partitioning,Q&P)钢由于具有优异的综合性能而备受关注。本文设计了一步等温和二步等温处理工艺,通过改变淬火温度和等温温度获得了不同含量一次马氏体(PM)、残余奥氏体(RA)、二次马氏体(FM)及贝氏体(BF)的多相微观结构。采用XRD、EBSD综合分析了淬火配分处理对马氏体/贝氏体形态、位错密度、体积含量、变体选择行为以及冲击韧性的影响。示波冲击试验结果表明:330℃是一步淬火配分和二步淬火配分处理的最佳淬火温度,该温度能够获得最佳的冲击韧性。与一步淬火配分处理比较,二步淬火配分处理可以提高复相组织中的RA含量,并降低FM含量。最优的淬火温度和配分温度有利于降低马氏体/贝氏体(M/B)中的位错密度、增加RA和大角度晶界(HAGB)体积含量,从而显著改善Q&P钢的冲击韧性。展开更多
Historical optical data are combined on the BL Lac object OQ 530. Verifying the existence of correlations among the flux variations in different bands serves as an important tool to investigate emission processes. To ...Historical optical data are combined on the BL Lac object OQ 530. Verifying the existence of correlations among the flux variations in different bands serves as an important tool to investigate emission processes. To examine the possible existence of a lag between variations in different optical bands from this source, a statistical analysis is performed through the discrete correlation function （DCF） method and the z-transformed discrete correlation function （ZDCF） method. Monte Carlo simulations called ＂flux redistribution/random subset selection＂ （FR/RSS） are performed to obtain statistically meaningful values for the cross-correlation time lags and their related uncertainties. The analysis confirms that the variations in different optical light curves are strongly correlated, with zero-lag within the errors. Long term variability of color indexes is also analyzed. The result suggests a strong correlation between color index and brightness. A clear bluer-when-brighter chromatism is found, in the sense that the spectrum steepens as the brightness decreases.展开更多
We present quasi-simultaneous VLBI images of the GHz-Peaked-Spectrum radio source OQ 208 obtained with the Very Long Baseline Array at 1.4, 1.7, 2.3, 5.0, 8.4, 15.4 GHz and the European VLBI Network at 6.7 GHz. The lo...We present quasi-simultaneous VLBI images of the GHz-Peaked-Spectrum radio source OQ 208 obtained with the Very Long Baseline Array at 1.4, 1.7, 2.3, 5.0, 8.4, 15.4 GHz and the European VLBI Network at 6.7 GHz. The low frequency （1.4, 1.7 and 2.3 GHz） observations reveal a weak and extended steep-spectrum component at about 30 mas away at position angle - 110°, which may be a remnant emission. The radio structure of OQ 208 consists of two mini-lobes at 5.0, 6.7, 8.4 and 15.4 GHz. Our spectral analysis further confirms that the southwest lobe undergoes free-free absorption and finds that the free-free absorption is stronger in the inner region. By fitting the 8.4 GHz images from 1994 to 2005, we obtain a separation speed of 0.0314-0.006 mas yr^-1 between the two mini-lobes. This indicates a jet proper motion of 0.1054-0.020 c and a kinematic age of 219±42 yr for the radio source.展开更多
The post-1994 observations of the blazar OQ 530 in optical BVRI bands, and radio observations at 22 GHz and 37 GHz were collected. The date compensated discrete Fourier transform （DCDFr） and CLEANest methods were us...The post-1994 observations of the blazar OQ 530 in optical BVRI bands, and radio observations at 22 GHz and 37 GHz were collected. The date compensated discrete Fourier transform （DCDFr） and CLEANest methods were used to search for possible periodicities. Two possible periods of 456±100 days and 258±29 days were found in the optical bands. The existence of possible correlations between the optical and radio emissions was investigated by means of discrete correlation function （DCF） analysis, and no significant correlation was found. Some possible mechanisms for the periodic variability are discussed.展开更多
文摘淬火-配分(Quenching and Partitioning,Q&P)钢由于具有优异的综合性能而备受关注。本文设计了一步等温和二步等温处理工艺,通过改变淬火温度和等温温度获得了不同含量一次马氏体(PM)、残余奥氏体(RA)、二次马氏体(FM)及贝氏体(BF)的多相微观结构。采用XRD、EBSD综合分析了淬火配分处理对马氏体/贝氏体形态、位错密度、体积含量、变体选择行为以及冲击韧性的影响。示波冲击试验结果表明:330℃是一步淬火配分和二步淬火配分处理的最佳淬火温度,该温度能够获得最佳的冲击韧性。与一步淬火配分处理比较,二步淬火配分处理可以提高复相组织中的RA含量,并降低FM含量。最优的淬火温度和配分温度有利于降低马氏体/贝氏体(M/B)中的位错密度、增加RA和大角度晶界(HAGB)体积含量,从而显著改善Q&P钢的冲击韧性。
基金Supported by the National Natural Science Foundation of China (Grant No. 10975145)funded by Fuyang Normal College, the Research Foundation of the Department of Education of Anhui Province (KJ2010B159)
文摘Historical optical data are combined on the BL Lac object OQ 530. Verifying the existence of correlations among the flux variations in different bands serves as an important tool to investigate emission processes. To examine the possible existence of a lag between variations in different optical bands from this source, a statistical analysis is performed through the discrete correlation function （DCF） method and the z-transformed discrete correlation function （ZDCF） method. Monte Carlo simulations called ＂flux redistribution/random subset selection＂ （FR/RSS） are performed to obtain statistically meaningful values for the cross-correlation time lags and their related uncertainties. The analysis confirms that the variations in different optical light curves are strongly correlated, with zero-lag within the errors. Long term variability of color indexes is also analyzed. The result suggests a strong correlation between color index and brightness. A clear bluer-when-brighter chromatism is found, in the sense that the spectrum steepens as the brightness decreases.
基金Supported by the National Natural Science Foundation of China.
文摘We present quasi-simultaneous VLBI images of the GHz-Peaked-Spectrum radio source OQ 208 obtained with the Very Long Baseline Array at 1.4, 1.7, 2.3, 5.0, 8.4, 15.4 GHz and the European VLBI Network at 6.7 GHz. The low frequency （1.4, 1.7 and 2.3 GHz） observations reveal a weak and extended steep-spectrum component at about 30 mas away at position angle - 110°, which may be a remnant emission. The radio structure of OQ 208 consists of two mini-lobes at 5.0, 6.7, 8.4 and 15.4 GHz. Our spectral analysis further confirms that the southwest lobe undergoes free-free absorption and finds that the free-free absorption is stronger in the inner region. By fitting the 8.4 GHz images from 1994 to 2005, we obtain a separation speed of 0.0314-0.006 mas yr^-1 between the two mini-lobes. This indicates a jet proper motion of 0.1054-0.020 c and a kinematic age of 219±42 yr for the radio source.
基金the National Natural Science Foundation of China
文摘The post-1994 observations of the blazar OQ 530 in optical BVRI bands, and radio observations at 22 GHz and 37 GHz were collected. The date compensated discrete Fourier transform （DCDFr） and CLEANest methods were used to search for possible periodicities. Two possible periods of 456±100 days and 258±29 days were found in the optical bands. The existence of possible correlations between the optical and radio emissions was investigated by means of discrete correlation function （DCF） analysis, and no significant correlation was found. Some possible mechanisms for the periodic variability are discussed.
