YAP:Ce闪烁晶体的光致激发荧光衰减常数测量

用波长为266nm的激光激发不同尺寸、不同掺Ce3+浓度的YAP:Ce闪烁晶体,测量其光致激光荧光衰减常数,测量结果表明:YAP:Ce闪烁晶体的光致荧光衰减常数约为18.2ns,且与实验晶体厚度及Ce3+掺杂浓度(0.1;～0.6;原子分数)无关.     

Fitting models to correlated data (large samples)

The study of the ordered series of residuals of a fit proved to be useful in evaluating separately the pure experimental error and the model bias leading to a possible improvement of the modeling [J. Mol. Spectrosc. 217 (2003) 32]. In the present work this procedure is extended to homogeneous correlated data. This new method allows a separate estimation of pure experimental error, model bias, and data correlation; furthermore, it brings a new insight into the difference between goodness of fit and model relevance. It can be considered either as a study of ‘random systematic errors’ or as an extended approach of the Durbin-Watson problem [Biometrika 37 (1950) 409] taking into account the model error. In the present work an empirical approach is proposed for large samples (n?500) where numerical tests are done showing the accuracy and the limits of the method.     

基于能岗匹配的管理人员配置过程定性模拟研究

能岗匹配是人力资源配置的重要原则。实施动态环境下的能岗匹配需要模拟出管理者素质变量与岗位职能变量的变化趋势与程度，以及这两者的实时匹配程度。首先描述了管理者素质与管理岗位职能的变量，建立了用于能岗匹配的定性模拟模型，设计了状态变量知识表示方法及其转换规则。采用BP神经网络设计了管理人员能岗匹配度计算函数。最后设计了定性模拟步骤并给出了一个模拟应用实例。     

子孔径拼接法检测大口径光学镜面的精度分析

讨论了在用子孔径拼接法检测大口径光学镜面时的精度问题，并分别从理论上和实验中对拼接检验的精度做了定量分析。分别用平面消差、在非圆域内的Zemike多项式系数拟合和在圆域内的Zemike多项式系数拟合等三种方法对检测得到的波面面形数据进行数据处理。通过对这三种方法计算结果的分析，发现利用平面消差法拟合波面数据能更好地保存原始波面信息，且拟合误差较小。最后通过对实验数据的分析和处理验证了平面消差法拟合得到的波面更接近原始波面，拼接效果较好。     

Zernike多项式拟合干涉面方法研究

本文就专著和文献中关于Zernike多项式拟合干涉波面几乎都建设采用Gram-Schimdt正交化方法,而不采用比较简单的传统经典的最小二乘法问题进行了深入研究,从理论和实践上严格地证明了两种方法的等价性。实践中发现,用最小二乘法求解Zernike多项式拟合系数的速度比用Gram-Schimdt正交化方法提高了三倍之多。由于在精密光测技术中,Zernike多项式已被广泛采用,因此,“等价性”的证明具有重要意义,并对于其它类似问题也有着普遍的参考价值。     

数字X射线图象的面不同一性校正研究

分析了数字X射线图象中面不同一性产生的原因,并从原理发出,采用曲面拟合的背景校正方法进行校正.实验表明该方法可以有效消除随机噪音对背景校正的影响,更好地提取出背景的不同一性特征信息,具有良好的校正效果.     

Curvature‐dependent adsorption of water inside and outside armchair carbon nanotubes

The curvature dependence of the physisorption properties of a water molecule inside and outside an armchair carbon nanotube (CNT) is investigated by an incremental density‐fitting local coupled cluster treatment with single and double excitations and perturbative triples (DF‐LCCSD(T)) study. Our results show that a water molecule outside and inside (n, n) CNTs (n = 4, 5, 6, 7, 8, 10) is stabilized by electron correlation. The adsorption energy of water inside CNTs decreases quickly with the decrease of curvature (increase of radius) and the configuration with the oxygen pointing toward the CNT wall is the most stable one. However, when the water molecule is adsorbed outside the CNT, the adsorption energy varies only slightly with the curvature and the configuration with hydrogens pointing toward the CNT wall is the most stable one. We also use the DF‐LCCSD(T) results to parameterize Lennard‐Jones (LJ) force fields for the interaction of water both with the inner and outer sides of CNTs and with graphene representing the zero curvature limit. It is not possible to reproduce all DF‐LCCSD(T) results for water inside and outside CNTs of different curvature by a single set of LJ parameters, but two sets have to be used instead. Each of the two resulting sets can reproduce three out of four minima of the effective potential curves reasonably well. These LJ models are then used to calculate the water adsorption energies of larger CNTs, approaching the graphene limit, thus bridging the gap between CNTs of increasing radius and flat graphene sheets. © 2016 Wiley Periodicals, Inc.     

A Note on First-Fit Coloring of Interval Graphs

We apply the Column Construction Method (Varadarajan et al., Proceedings of the Fifteenth Annual ACM-SIAM Symposium On Discrete Algorithms, pp. 562–571, 2004) to a minimal clique cover of an interval graph to obtain a new proof that First-Fit is 8-competitive for online coloring interval graphs. This proof also yields a new discovery that in each minimal clique cover of an interval graph G, there is a clique of size .     

Lowest Energy Singlet Transition in Biphenyl

The lowest energy band in the electronic absorption spectrum of biphenyl is broad and structureless. Considering a spectral comparison of biphenyl and related molecules, Platt² suggested that this band results from two different electronic transitions. Similarly, after making a fluorescence lifetime study, Berlman and Steingraber³ predicted that the first singlet transition should be forbidden and thus the broad band should contain a hidden band. In this note we confirm this prediction.     

Improved methods for fluorescence background subtraction from Raman spectra

Raman spectroscopy has attracted interest as a non‐invasive optical technique to study the composition and structure of a wide range of materials at the microscopic level. The intrinsic fluorescence background can be orders of magnitude stronger than the Raman scattering, and so, background removal is one of the foremost challenges for quantitative analysis of Raman spectra in many samples. A range of methods anchored in instrumental and computational programming approaches have been proposed for removing fluorescence background signals. An enhanced adaptive weighting scheme for automated fluorescence removal is reported, applicable to both polynomial fitting and penalized least squares approaches. Analysis of the background fitting results for ensembles of simulated spectra suggests that the method is robust and reliable and can significantly improve the background fit over the range of signal, shot noise and background parameters tested, while reducing the subjective nature of the process. The method was also illustrated by application to experimental data generated from aqueous solutions of bulk protein fibrinogen mixed with dextran. Copyright © 2013 John Wiley & Sons, Ltd.