Electronic properties of hydrogen storage materials with photon-in/photon-out soft-X-ray spectroscopy

The applications of resonant soft X-ray emission spectroscopy on a variety of carbon systems have yielded characteristic fingerprints. With high-resolution monochromatized synchrotron radiation excitation, resonant inelastic X-ray scattering has emerged as a new source of information about electronic structure and excitation dynamics. Photon-in/photon-out soft-X-ray spectroscopy is used to study the electronic properties of fundamental materials, nanostructure, and complex hydrides and will offer potential in-depth understanding of chemisorption and/or physisorption mechanisms of hydrogen adsorption/desorption capacity and kinetics.     

3μm与2μm级联振荡Ho3+:ZBLAN光纤激光器的动态特性分析

基于传输速率方程,对Ho3+:ZBLAN光纤激光器的动态特性--上能级粒子数以及输出激光功率的弛豫振荡特性进行了数值分析.通过忽略光纤参数对传输方向的依赖性,抽运光和信号光的功率传输方程被分别简化处理.结果表明,在5I6能级的粒子数首先经历一次弛豫振荡后,5I6和5I7能级的粒子数交替弛豫振荡并达到稳态;同样,在3μm波长的激光功率首先经历一次弛豫振荡后,3μm和2μm波长的激光功率交替弛豫振荡并达到稳态,而且,弛豫振荡时的峰值功率远大于稳态时的激光功率.     

两种基于空间与光谱相结合的TM影像端元提取算法

针对TM影像波段少,光谱信息相对不丰富的情况,提出了两种结合空间与光谱信息的端元提取算法.首先,提出了基于空间分块的端元提取算法,该算法先对影像进行快速浏览,根据地物分布的复杂程度,确定分块的方案,在分块的基础上通过沙漏算法迅速地提取端元;其次,提出了一种基于空间连续性的端元提取算法,此算法也在分块思路指导下,通过光谱...     

<Emphasis Type="Italic">G</Emphasis>-covering subgroup systems for the classes of supersoluble and nilpotent groups

LetF be a class of groups andG a group. We call a set Σ of subgroups ofG aG-covering subgroup system for the classF (or directly aF-covering subgroup system ofG) ifG ∈F whenever every subgroup in Σ is inF. In this paper, we provide some nontrivial sets of subgroups of a finite groupG which are simultaneouslyG-covering subgroup systems for the classes of supersoluble and nilpotent groups. Research of the first author is supported by the NNSF of China (Grant No. 10171086) and QLGCF of Jiangsu Province and a Croucher Fellowship of Hong Kong. Research of the second author is partially supported by a UGC (HK) grant #2060176 (2001/2002).     

拟次酉阵与拟次Hermite阵

提出了拟次酉阵、拟(反)次Hermite阵概念，研究了它们的性质及其相互间的关系，将正交矩阵广义Gayley分解推广到拟次酉阵上。     

Variational estimates of chiral order parameter in 1+1 dimensional lattice QCD

We discuss analytically the vacuum structure and chiral-symmetry breaking in 1+1 dimensional lattice QCD with naive and Wilson fermions, using a unitary transformation and the variational method developed recently. As an example, the chiral order parameter is evaluated systematically for any coupling constant and fermion mass by including the multilink-terms in the transformation. The expected scaling behavior is observed. Our results are consistent with the continuum predictions.     

无限群分次环的Smash Product的理想交性质

Ｇ是群，Ｒ是Ｇ－分次环．本文将有限群Ｇ分次环Ｒ与Ｇ的ｓｍａｓｈｐｒｏｄｕｃｔＲ＃Ｇ￣＊的理想交性质推广到无限群的情形．证明了：Ｇ是无限群，Ｒ是非奇异Ｇ－分次环．Ｒ与Ｇ的广义ｓｍａｓｈｐｒｏｄｕｃｔＲ＃Ｇ￣＊有理想交性质的充要条件，对任意０≠ａ＿ｅ∈Ｒ＿ｅ．     

Porphyrin-like porous nanomaterials as drug delivery systems for ibuprofen drug

In recent years, nanomaterial-based drug delivery carriers have become some of the most attractive to be studied. The purpose of this study is to investigate the interaction of C60 fullerene, carbon nanotube and graphene having porphyrin-like FeN4 clusters with a non-steroidal anti-inflammatory drug (ibuprofen) by means of the density functional theory. Results showed that the graphene with FeN4 clusters could remarkably increase the tendency of graphene for adsorption of ibuprofen drug. Also, our ultraviolet–visible results show that the electronic spectra of the complexes exhibit a blue shift toward lower wavelengths (higher energies). It was found that Ibp/FeN4-graphene had high chemical reactivity, which was important for binding of the drug onto the target site. In order to go further and gain insight into the binding features of considered systems with ibuprofen drug, the Atoms in Molecules analysis was performed. Our results determine the electrostatic features of the Ibp/FeN4-graphene bonding. Consequently, the results demonstrated that the FeN4-graphene could be used as potential carriers for the delivery of ibuprofen drug.     

Contact ratio of rough surfaces with multiple asperities in mixed lubrication at high pressures

Relative optical intensity interference was used to measure the lubrication film thickness when four kinds of polyalphaolefin (PAO) were used as lubricants confined between a smooth sapphire disc surface and a rough steel ball surface. Maximum Hertz contact pressure up to 3 GPa was applied in the central part of the contact region in mixed lubrication. It was found that the contact ratio (the ratio of real contact region to the whole nominal contact region) is related to the film thickness, the applied pressure, the surface roughness and the rolling speed, and so on. Contact ratio evidently reduces as lubrication film thickness or rolling speed increases. Quantitative relationship between the contact ratio and the influence factors was summarized based on the nonlinear fitting of experimental measurements. A formula was put forward to calculate the contact ratio at high pressure conditions according to the current experimental results.     

One-pot synthesis of ferromagnetic Fe2.25W0.75O4 nanoparticles as a magnetically recyclable photocatalyst

ZnO nanostructures, including nanowires, nanorods, and nanoneedles, have been deposited on GaAs substrates by the two-step chemical bath synthesis. It was demonstrated that the O₂-plasma treatment of GaAs substrates prior to the sol?Cgel deposition of seed layers was essential to conformally grow the nanostructures instead of 2D ZnO bunches and grains on the seed layers. Via adjusting the growth time and concentration of precursors, nanostructures with different average diameter (26?C225?nm), length (0.98?C2.29???m), and density (1.9?C15.3?×?10⁹?cm^?2) can be obtained. To the best of our knowledge, this is the first demonstration of ZnO nanostructure arrays grown on GaAs substrates by the two-step chemical bath synthesis. As an anti-reflection layer on GaAs-based solar cells, the array of ZnO nanoneedles with an average diameter of 125?nm, a moderate length of 2.29???m, and the distribution density of 9.8?×?10⁹ cm^?2 has increased the power conversion efficiency from 7.3 to 12.2?%, corresponding to a 67?% improvement.