静-动加载相结合的材料状态方程实验平台的研制

根据神光-Ⅱ第九路高功率激光加载的特点,对传统静高压金刚石压砧装置进行了改进和优化设计,研制出了适合高功率激光加载条件下材料宽域状态方程研究的新型静高压靶.在神光-Ⅱ高功率激光装置上建立了基于静高压金刚石压砧和动高压激光相结合的材料宽域状态方程研究平台.利用这一平台开展了超纯水的宽域状态方程实验探索,获得了较好的实验结果.     

A Mechanochemical-Assisted Synthesis of Boron,Nitrogen Co-Doped Porous Carbons as Metal-Free Catalysts

A green and convenient solid-state method assisted by mechanical energy is employed for the synthesis of boron (B) and nitrogen (N) co-doped porous carbons (B,N-Cs). Glutamic acid (Glu) and boric acid (H₃BO₃) are used as the N-containing carbon precursor and boron source, respectively. This method is easy to perform and proved to be efficient towards co-doping B and N into the carbon matrix with high contents of B (7 atom %) and N (10 atom %). By adjusting the molar ratio of H₃BO₃ to Glu, the surface chemical states of B and N could be readily modulated. When increasing H₃BO₃ dosage, the pore size of B,N-Cs could be tuned ranging from micropores to mesopores with a Brunauer–Emmett–Teller (BET) surface area up to 940 m² g⁻¹. Finally, the B,N-Cs were applied as metal-free catalysts for the cycloaddition of CO₂ to epoxides, which outperform the N-doped carbon catalyst (NC-900) and the physically mixed catalyst of NC-900/B₄C. The enhanced activity is attributed to the cooperative effect between B and N sites. X-ray photoelectron spectroscopy (XPS) analysis reveals that BN₃ in the B,N-Cs serves as a critical active site for the cooperative catalysis.     

基于离散Fourier变换的内源全息图重构计算方法

对基于离散Fourier变换的内源全息图重构计算方法作了深入系统的分析，讨论了如何计算整个球面全息图对原子重构像的贡献，克服了以往该方法只能计算半个球面全息图的不足，并运用采样定理知识，分析了全息图的采样率、重构像的空间范围和分辨率等问题. 关键词： 内源全息术 离散Fourier变换 采样定理 同步辐射     

Focusing high-energy x-rays by a PMMA compound x-ray lens on Beijing synchrotron radiation facility

The x-ray compound lens is a novel refractive x-ray optical device. This paper reports the authors' recent research on a polymethyl methacrylate (PMMA) compound x-ray lens. Firstly the designing and LIGA fabrication process for the PMMA compound x-ray lens are briefly described. Then, a method for theoretical analysis, as well as the experimental system for measurement is also introduced. Finally, the focusing spots for 8keV monochromatic x-rays by the PMMA compound x-ray lens are measured and analysed. According to the experimental results, it is concluded that the PMMA compound x-ray lens promises a good focusing performance under the high-energy x-rays.