New rare earth vanadates YSr_(Q-x)Ca_xV_3O_(9-y)(x=0.0, 0.67, 1.0, 1.33 and 2.0) have been synthesized by a new simple method. X-ray powder diffraction results show that they are mono-phase. They belong to orthorhombi...New rare earth vanadates YSr_(Q-x)Ca_xV_3O_(9-y)(x=0.0, 0.67, 1.0, 1.33 and 2.0) have been synthesized by a new simple method. X-ray powder diffraction results show that they are mono-phase. They belong to orthorhombic structure and their lattice constants are calculated. The results of weight gains in TG curves show that the lower valent vanadium is oxidized to higher valent state at higher temperature. The oxygen contents of new compounds are calculated from the weight gains. Both V^(3+) and V^(4+) coexist in YSr_(2-x)Ca_xV_3O_(9-y). These compounds exhibit low electric resistivity at room temperature.展开更多
We present a detailed clustering analysis of a large K-band selected local galaxy sample, which is constructed from the 2MASS and the SDSS and consists of 82486 galaxies with 10 〈 K 〈 13.5 and 0.01 〈 z 〈 0.1. The ...We present a detailed clustering analysis of a large K-band selected local galaxy sample, which is constructed from the 2MASS and the SDSS and consists of 82486 galaxies with 10 〈 K 〈 13.5 and 0.01 〈 z 〈 0.1. The two-point correlation function of the magnitude-limited sample in real space at small scales is well described by the power law ∈（r） = （r/6.44 ± 0.23）^-1.81±0.02. The pairwise velocity dispersion is derived from the anisotropic two-point correlation function and we find the dispersion δ12 = 685 ± 17 kms^-1 if scale invariance is assumed, which is larger than values measured in the optical bands of the selected galaxy samples. We further investigate the dependence of the two-point correlation function and the δ12 on the g- r color and the K- band luminosity, and obtain similar results to previous works in optical bands. Comparing a mock galaxy sample with our real data indicates that the semi-analytical model cannot mimic the δ12 in observation, although it can approximate the two-point correlation function within measurement uncertainties.展开更多
文摘New rare earth vanadates YSr_(Q-x)Ca_xV_3O_(9-y)(x=0.0, 0.67, 1.0, 1.33 and 2.0) have been synthesized by a new simple method. X-ray powder diffraction results show that they are mono-phase. They belong to orthorhombic structure and their lattice constants are calculated. The results of weight gains in TG curves show that the lower valent vanadium is oxidized to higher valent state at higher temperature. The oxygen contents of new compounds are calculated from the weight gains. Both V^(3+) and V^(4+) coexist in YSr_(2-x)Ca_xV_3O_(9-y). These compounds exhibit low electric resistivity at room temperature.
基金Supported by the National Natural Science Foundation of China undergrant Nos.10643002,10633040,10873035,10725314the Ministry of Science & Technology of China through 973 grant No.2007CB815402Support of the Chinese 863 project (No.2006AA01A125)
文摘We present a detailed clustering analysis of a large K-band selected local galaxy sample, which is constructed from the 2MASS and the SDSS and consists of 82486 galaxies with 10 〈 K 〈 13.5 and 0.01 〈 z 〈 0.1. The two-point correlation function of the magnitude-limited sample in real space at small scales is well described by the power law ∈（r） = （r/6.44 ± 0.23）^-1.81±0.02. The pairwise velocity dispersion is derived from the anisotropic two-point correlation function and we find the dispersion δ12 = 685 ± 17 kms^-1 if scale invariance is assumed, which is larger than values measured in the optical bands of the selected galaxy samples. We further investigate the dependence of the two-point correlation function and the δ12 on the g- r color and the K- band luminosity, and obtain similar results to previous works in optical bands. Comparing a mock galaxy sample with our real data indicates that the semi-analytical model cannot mimic the δ12 in observation, although it can approximate the two-point correlation function within measurement uncertainties.
