Cosmic rays from the knee to the ankle

The shape and composition of the primary spectrum as well as the large-scale anisotropy in the arrival direction of cosmic rays are key elements to understand the origin, acceleration and propagation of the Galactic radiation. Besides the well-known knee and ankle features, the measured energy spectrum exhibits also a less pronounced but still clear deviation from a single power law between the knee and the ankle, with a spectral hardening at $\sim 2\times {10}^{16}\text{eV}$ and a steepening at $\sim {10}^{17}\text{eV}$. The average mass composition gets heavier after the knee till $\sim {10}^{17}\text{eV}$, where a bending of the heavy component is observed. An indication of a hardening of the light component just above ${10}^{17}\text{eV}$ has been measured as well. First indications of anisotropy of the arrival direction in the southern hemisphere have been reported at $\sim {10}^{15}\text{eV}$.     

Effect of nitrogen content on the properties of CrNxOyCz coating prepared by DC reactive magnetron sputtering

The CrN_xO_yC_z coatings were deposited by planar DC reactive magnetron sputtering onto AZ31 Mg alloy and high speed tool steel (HSTS) substrates at a substrate temperature of 200 °C. The effect of N₂ content on composition and structure of the CrN_xO_yC_z coatings was investigated. The structure of the CrN_xO_yC_z coatings was analyzed by a glancing angle X-ray diffraction (GXRD). The cross-section morphology and thickness of the CrN_xO_yC_z coatings were checked by a field emission scanning electron microscope (FESEM), and the composition profile and chemical state were carried out by an X-ray photoelectron spectroscopy (XPS). The experimental results showed that the structure and phase composition of the CrN_xO_yC_z coatings depended on N₂ content. The evolution of the structure of CrN_xO_yC_z coatings was consistent with CrN_x-based coatings, and the CrN_xO_yC_z coatings contained Cr₂O₃, CrO₂, CrO, Cr₃C₂, CrN_x (Cr, CrN, Cr₂N), as well as different chromium oxynitride. However, the carbide and oxynitride were oxidized after annealing.     

自贡地区恐龙骨骼化石及围岩特征的研究

自贡地区恐龙化石埋藏丰富、分布广泛、保存完整,具有重要的科学价值、社会价值和经济价值。用X荧光衍射研究自贡恐龙骨骼化石及围岩元素组成,XRD结合红外光谱仪分析确定化石的矿物组成,化石切片和显微观察了解骨骼内部构造和填充物质。恐龙骨骼化石及围岩中的含钙量均较高(5%),但化石含钙量达到30%以上;化石中的含硅量较低(0.24%—1.45%),围岩中的含硅量较高(14%);化石中的含磷量为围岩的46倍以上。化石的主要化学成分是碳氟磷灰石,其次是碳酸钙;围岩的主要成分是二氧化硅。实验结果可为恐龙化石的鉴别及保护材料的研制提供理论依据。     

基于max-product复合的模糊矩阵幂序列的收敛性及其分类

主要讨论模糊矩阵在max-product复合意义下的收敛性.通过对模糊矩阵元素的有限收敛、无限收敛、有限振荡、无限振荡的情况的讨论,引入模糊矩阵的有限收敛、无限收敛、有限振荡、无限振荡的概念,证明模糊矩阵在max-product复合意义下要么有限收敛,要么无限收敛,要么有限振荡,要么无限振荡,给出了模糊矩阵在max-product复合意义下收敛性的完整结论,并澄清已有文献中的一些错误.最后给出基于max-product复合的模糊矩阵幂序列的分类情况.     

单位球上正规权Zygmund空间上的加权复合算子

设μ是[0,1)上的一个正规函数,φ是Cⁿ中单位球B上的一个全纯自映射,ψ是B上的一个全纯函数.在本文中,作者刻画了Cⁿ中单位球上具有正规权μ的Zygmund型空间Z_μ(B)上加权复合算子ψC_φ的有界性和紧性.     

Composition operators on the polydisc

In this paper we study the boundedness of composition operators on the weighted Bergman spaces and the Hardy space over the polydisc ${\mathbb{D}}^n$. Studying the volume of sublevel sets we show for which n the necessary conditions obtained by Bayart are sufficient. For arbitrary polydisc we prove the rank sufficiency theorem which, in particular, provides us with a simple criterion describing boundedness of composition operators on the spaces over the bidisc. Such a consistent characterization is obtained for the classical Bergman space over the tridisc.