双回碰机制下双电子谐波发射的特点

本文数值研究了阿秒分辨下双电子He原子发射高次谐波的特点.数值计算结果表明,双电子谐波光谱的截止能量与单电子相比有较大延伸,并且我们发现了一些新的截止能量.随后分析显示,这些新的截止能量是由双电子的双回碰机制所导致的,并且电子相关效应在里面起到了很重要的作用.     

Potency of Attenuated Eimeria tenella in Protective Immunity Induction on Homologous and Heterologous Challenges

The aim of this study was to know the protective immunity of broilers immunized with attenuated Eimeria tenella (E. tenella) on homologous and heterologous challenges. The protective immunity was represented by oocyst production and histopathological changes of cecum. The previous experiment already produced attenuated E. tenella through serial passages of precocious lines in naive chicken. Four groups of chickens were separately divided into two non-immunized control groups and two immunized with attenuated E. tenella groups, and each group was challenged with homologous and heterologous strains. The results showed significant difference in oocysts production (p<0.01) and histopathological changes between control and immunized groups.     

Prompt isothermal decay of thermoluminescence in MgB4O7:Dy,Na and LiB4O7:Cu,In dosimeters

According to standard delocalized kinetic models of thermoluminescence (TL), when an irradiated sample is held at a high temperature T, the isothermal TL signal will decay with a characteristic thermal decay constant λ which depends strongly on the temperature T. This prediction of standard delocalized kinetic theory is investigated in this paper by studying two TL dosimeters, MgB₄O₇:Dy, Na and LiB₄O₇:Cu, In (hereafter MBO and LBO correspondingly). In the case of LBO it was found that the thermal decay constant λ of the main dosimetric TL peak follows exactly the predictions of standard delocalized kinetic theory. Furthermore, the thermal activation energy of the main peak evaluated by the isothermal decay method is in full agreement with values obtained from initial rise and glow curve fitting methods. However, in the case of MBO it was found that the thermal decay constant λ varies little with the isothermal decay temperature T. In order to explain these unusual results for MBO, the TL glow curves and isothermal decay curves were analyzed using analytical expressions derived recently from a radiative tunneling recombination model. Based on the different behavior of the two TL dosimeters, it is suggested that the isothermal decay of TL at high temperatures can be used to discriminate between radiative delocalized recombination and radiative localized recombination processes.     

一个新的有机同系物电离能拟合公式

本文提出有机同系物电离能拟合公式: NlogIp=a+bn, 其中N为组成同系物分子的原子总数, n为重复单元的重复度, a, b是和能级有关的常数。以NlogIp对n进行线性回归分析, 结果46个同系列150组光电子能谱数据所得相关系数r全部大于0.997, 其中131组达到1.000,优秀率为100%。     

Exploring the Effect of Ammonium Iodide Salts Employed in Multication Perovskite Solar Cells with a Carbon Electrode

Perovskite solar cells that use carbon (C) as a replacement of the typical metal electrodes, which are most commonly employed, have received growing interest over the past years, owing to their low cost, ease of fabrication and high stability under ambient conditions. Even though Power Conversion Efficiencies (PCEs) have increased over the years, there is still room for improvement, in order to compete with metal-based devices, which exceed 25% efficiency. With the scope of increasing the PCE of Carbon based Perovskite Solar Cells (C-PSCs), in this work we have employed a series of ammonium iodides (ammonium iodide, ethylammonium iodide, tetrabutyl ammonium iodide, phenethylammonium iodide and 5-ammonium valeric acid iodide) as additives in the multiple cation-mixed halide perovskite precursor solution. This has led to a significant increase in the PCE of the corresponding devices, by having a positive impact on the photocurrent values obtained, which exhibited an increase exceeding 20%, from 19.8 mA/cm², for the reference perovskite, to 24 mA/cm², for the additive-based perovskite. At the same time, the ammonium iodide salts were used in a post-treatment method. By passivating the defects, which provide charge recombination centers, an improved performance of the C-PSCs has been achieved, with enhanced FF values reaching 59%, which is a promising result for C-PSCs, and V_oc values up to 850 mV. By combining the results of these parallel investigations, C-PSCs of the triple mesoscopic structure with a PCE exceeding 10% have been achieved, while the in-depth investigation of the effects of ammonium iodides in this PSC structure provide a fruitful insight towards the optimum exploitation of interface and bulk engineering, for high efficiency and stable C-PSCs, with a structure that is favorable for large area applications.     

双电子复合过程在激光在Au靶耦合物理中的作用

 描述了考虑双电子复合过程的平均原子模型,通过与流体力学耦合计算,对双电子复合过程在激光－Au靶耦合物理中的作用进行了总体计算,结果表明,双电子复合对等离子体状态及X光转换等有明显影响,特别表现在晕区电子温度、电离度的降低,激光－X光的转换效率的提高以及X光的发光区域变宽等。     

Formation of small water cluster anions by attachment of very slow electrons at high resolution

Using a high resolution laser photoelectron attachment method, we have studied the formation of (H ₂ O) _q ^- (q = 2, 6, 7, 11, 15) cluster ions in collisions of slow free electrons (E = 1-80 meV) and Rydberg electrons (n = 12-300) with water clusters. Resonances at zero energy have been observed, the shapes of which are strongly dependent on cluster size. The results are discussed in terms of the formation of metastable negative ions. Received 8 March 1999     

由宽波段多光子作用产生的锂分子高位态受激辐射

本文报道了以６２０．６￣６６５．０ｎｍ范围内任意波长激光作用下产生的锂分子高位态紫外扩散带受激辐射的实验结果,在锂分子－原子系统中,由激光双光子激发、并通过碰撞能量转移过程以及多光子电离复合过程使锂分子高位态获得布居,从而得到紫外区扩散受激辐射,该辐射来自较高的某个三重态向低排斥态ａ＾３Σｕ＾＋的跃迁的结果。文中对有关的辐射特性及激发机制进行了详细的分析和讨论。     

Evaluation of Dead Time Calculation in Reversed-Phase Liquid Chromatography Using a Multiparametric Mathematical Method

In reversed phase liquid chromatography (RP-HPLC), the validity of a multiparametric non-linear least-squares regression iterative method for the determination of the column dead time t_M and the regression parameter (slope b), based on the use of alkan-2-ones, alkyl aryl ketones, and 1-nitroalkanes has been evaluated. The determination of t_M and b has been extensively studied for two mobile phase systems acetonitrile-water and methanol-water on seven octadecyl-C₁₈ and one octyl C₈ analytical columns. The calculated t_M and b values were compared with those obtained by Guardino's and Grobler's methods. The influence exerted thereon by the nature of the homologous series, the mobile phase composition, and the packing materials were investigated.