Is cosmology compatible with sterile neutrinos?

By combining data from cosmic microwave background experiments (including the recent WMAP third year results), large scale structure, and Lyman-alpha forest observations, we constrain the hypothesis of a fourth, sterile, massive neutrino. For the 3 massless+1 massive neutrino case, we bound the mass of the sterile neutrino to ms<0.26 eV (0.44 eV) at 95% (99.9%) C.L., which excludes at high significance the sterile neutrino hypothesis as an explanation of the LSND anomaly. We generalize the analysis to account for active neutrino masses and the possibility that the sterile abundance is not thermal. In the latter case, the contraints in the plane are nontrivial. For a mass of >1 or <0.05 eV, the cosmological energy density in sterile neutrinos is always constrained to be omeganu<0.003 at 95% C.L., but for a mass of approximately 0.25 eV, omeganu can be as large as 0.01.     

岩石某些力学参数的试验研究

本文对正长岩岩块进行了静态条件下的摩擦系数试验研究,并在振动台上进行了动态条件下摩擦系数的试验。试验结果表明静态条件下的静摩擦系数高于动态条件下的静摩擦系数。两种条件下的动摩擦系数的变化规律也有明显区别。     

Effects of SiO2 coating on luminescence property and thermostability of Sr2MgSi2O7: Eu2+, Dy3+ phosphors

Journal of Sol-Gel Science and Technology - Sr2MgSi2O7: Eu2+, Dy3+ phosphor powders are unstable and degrade at elevated temperature, thus limiting their applications in the medium to high...     

硼酸铝晶须的研究及应用进展

硼酸铝晶须因其熔点高、强度接近完美晶体、耐磨、耐高温、耐腐蚀、电绝缘性好、价格相对低廉等优点,被作为增强体广泛应用于高分子材料、金属材料、陶瓷、透波材料、涂料等领域。本文综述了硼酸铝晶须的性能、用途、合成机理、制备方法等国内外研究进展,以期为硼酸铝晶须的进一步研发、应用作指导。     

新型多孔莫来石纤维陶瓷负载La0.8Sr0.2CoO3-δ钙钛矿催化剂

 利用空气挤压排液成型法在 1250 ℃下制得了高孔隙率高热稳定性的莫来石纤维陶瓷. 这种多孔莫来石纤维陶瓷具有较均匀的孔分布,并且孔隙率高达96.22%. 以这种多孔陶瓷为载体制备了负载型La0.8Sr0.2CoO3-δ钙钛矿催化剂,该催化剂对NO氧化CO表现出很好的催化活性和稳定性. 在催化剂中掺入贵金属Pd之后,催化剂的催化活性得到了很大的提高.