The structure and vibrational features of proton disolvates in water–ethanol solutions of HCl: the combined spectroscopic and theoretical study

The infrared (IR) spectra of water–ethanol (EtOH) solutions of HCl are measured over a wide range of acid concentration at fixed H₂O―EtOH ratios (1 : 1, 1 : 2, and 1 : 40). In these systems, different proton disolvates with (quasi)symmetrical H‐bonds are formed. Their structure and vibrational features are revealed by the density functional theory method coupled with the polarizable continuum model of solvation. In dilute acidic solutions, the Zundel‐type H₅O₂⁺ ion is mainly formed. In concentrated HCl solutions, the ions (H₂O···H···O(H)Et)⁺ and (Et(H)O···H···O(H)Et)⁺ with the quasi‐symmetrical O···H⁺···O unit having O···O separation <2.45 Å appear. The first ion characterized by the IR‐intensive band around 1800 cm^?1 is mainly formed in the 1 : 1 water–ethanol systems. The second ion exists in the 1 : 2 and 1 : 40 water–ethanol systems. Its spectroscopic signatures are the groups of the IR‐intensive bands around 800 and 1050 cm^?1. In highly concentrated HCl solutions with the 1 : 40 water–ethanol ratio, a neutral Et(H)O···H⁺···Cl^? complex exists. Copyright © 2013 John Wiley & Sons, Ltd.     

Collective excitations in a confined,interacting dilute Bose-condensed fluid

In the Thomas–Fermi (TF) regime, S. Stringari [Phys. Rev. Lett., 77, 2360 (1996)] established the hydrodynamic normal modes of an interacting dilute Bose-condensed fluid confined in an isotropic harmonic trap. Here, we extend this treatment beyond the TF condensate using the work of B. Hu, G. Huang and Y. Ma [Phys. Rev. A, 69, 063608 (2004)] as a starting point. Both numerical results for low-lying eigenfrequencies, for various angular momentum quantum numbers???and n?=?0, and also samples of corresponding eigenfunctions, are presented. Finally, eigenfrequencies are also given for some collective excitations in an axially symmetrical trap.     

基于小波分解系数的贝叶斯人脸识别方法

本文给出了贝叶斯人脸识别方法中匹配准则的多个近似表达式及一种实用的快速计算方法,在此基础上,利用反对称双正交小波变换的微分算子功能,提出了一种利用两幅人脸图像的小波变换系数差作为模式矢量的贝叶斯人脸识别方法,并利用AR人脸图象库进行了实验,实验结果表明本文方法与基于图像灰度的类似方法相比,识别率提高8％左右,此外本文方法也提供了一条在图像压缩数据域中实现人脸识别的可能途径。     

Investigation of the limit of lateral beam shifts on a symmetrical metal-cladding waveguide

This paper reports that Goos--H\"anchen (GH) shifts occurring on a symmetrical metal-cladding waveguide are experimentally identified. It was found that there exists a critical thickness of the upper metal layer, h_cr, above which negative shift is observed and, reversely, positive shift occurs. Both positive and negative GH shifts near the critical thickness do not vary dramatically and can achieve a maximum on the submillimeter scale, which is different from simulated results using the stationary-phase method. It also shows that this critical thickness, h_cr, can be obtained at the position for zero reflectivity by setting the intrinsic damping to be the same as the radiative damping. The GH effects observed near the critical thickness are produced by extreme distortion of the reflected beam profiles, which limits the amplitude of the GH shift and, further, the sensitivity of the GH optical sensor based on the symmetrical metal-cladding waveguide.     

含有大位移动边界的复杂流场的数值模拟

含有运动弹丸的膛口流场是典型的大位移动边界问题,同时弹丸在出膛过程中,流场的结构也会发生变化,增加了流场的复杂程度.在对该流场的数值模拟中,将它分为两个区:弹丸运动区和普通流场区,它们之间用一个特殊的分区边界联系,同时运用网格局部重构技术处理弹丸运动造成的网格变形问题,并将对称轴定义为网格变形边界,使得弹丸在对称轴上运动过程中不会导致对称轴上的网格体积为负.从计算结果可以看出整个膛口波系结构变化过程和弹丸先加速后减速的过程,从而表明该动网格处理方法是成功的.     

N型TOPCon晶硅太阳能电池光注入退火增效的研究

N型隧穿氧化层钝化接触(Tunnel Oxide Passivating Contacts,TOPCon)太阳能电池完成印刷烧结后,再经过光注入,效率有明显提升,主要表现在Voc(开路电压)及FF(填充因子)的提升.其机理在于通过温度和光照强度调节费米能级变化,控制H总量及价态来提高钝化性能.钝化膜层的质量、硅基体掺杂...     

液体炸药滑移内爆加载下钢管的变形与层裂破坏研究

用液体炸药滑移内爆加载方式,研究了不同炸药厚度和外壳条件下20钢圆管的内聚变形和破坏特征。实验中,钢管发生了较大径向应变,应变值大致随炸药厚度的增加而线性增大。在炸药厚度不低于3mm时钢管变形均匀,轴对称较好;药厚小于3mm时其变形不再是基本轴对称收缩,管子表面出现扭转褶皱。各种装药厚度下,均未观察到预期的层裂破坏。对未层裂的原因进行了初步分析。     

Grand canonical distribution for multicomponent system in the collective variables method

The collective variables method with a reference system is developed for the case of the grand canonical ensemble for a multicomponent continuous system. The method is used to investigate phase transitions in a binary system. For a binary symmetrical system the relations between microscopic parameters determining the alternation of gas-liquid and separation phase transitions are found. The functional of the grand partition function of the symmetrical mixture is examined in the framework of parameters containing the separation point. The system is described with two sets of collective variables: _k, a set connected with the gas-liquid critical point, andc _k, a set connected with the separation phenomenon. The fourfold basic density measure is constructed inc _k-variable phase space which contains the variablec _v connected with the order parameter of the system. It is shown that the problem can be reduced to the 3D Ising model in an external field.     

On minimal subgroups of finite groups

In this paper, the minimal subgroups of a finite group G are studied. Using the normalizes of Sylow subgroups of G, we obtain some sufficient conditions for G to be p-milpotent and supersolvable, which ae extensions of the related results of Burnside, Ito, Buckley and Asaad.     

两种估计区间解法的讨论

依据等概率对称区间和等密度对称区间的概念引出两种估计区间求解方法,并通过两种方法推导证明了等密度对称区间即为最短估计区间.然后分别就F分布和χ2分布情形对这两种区间估计方法作以比较.比较发现,在同样条件下,等密度对称区间总比概率对称区间要短,并且随着自由度增加,两种区间趋于重合.