面阵探测下的污染云团红外光谱仿真

研究污染云团的红外光谱仿真,对于利用仿真光谱进行光谱识别的算法研究十分重要.在单元探测器探测方式下污染云团的红外光谱仿真研究取得了一定成果,并且已经被应用于识别算法的研究工作中.针对基于成像光谱仪的污染云团识别算法研究缺乏实测数据的问题,利用具有高仿真精度的基于物理模型的污染云团扩散模型及其仿真结果网格化的特点,研究相应的云团红外光谱仿真多层模型,提出了面阵探测方式下污染云团红外光谱的仿真方法,生成了同时具有光谱维和空间维信息的数据立方体,为该研究领域提供了新的研究方法.提出的面阵探测方式下的污染云团红外光谱仿真直观地反映了污染云团的扩散,提供了完备且符合实际情况的污染云团红外光谱立方体数据,对于提高和完善红外光谱识别算法具有重要意义.     

掺镱石英光纤预制棒的制备与表征

采用改进化学汽相沉积结合溶液掺杂法制备了掺镱石英光纤预制棒,并研究了不同镱掺杂浓度下的吸收光谱和发光光谱.吸收光谱和发光光谱的强度随着YbCl₃溶液浓度的增大而增强.在不产生失透的前提下,得到预制棒芯层能够掺杂的YbCl₃溶液最大浓度为0.057 mol/L.     

U (2) algebraic model applied to vibrational spectra of Nickel Metalloporphyrins

In this paper the highly excited stretching and bending vibrational energy levels of some Nickel Metalloporphyrin molecules are studied by U (2) algebraic model. Its application to Nickel Octaethyl Porphyrin, Nickel Tetra Phenyl Porphyrin and Nickel Porphyrin are presented with fewer algebraic fitting parameters. The highly excited stretching and bending vibrational energy levels of these molecules are showing the energy clustering spectrum.     

Structural ordering of ω-ferrocenylalkanethiol monolayers on Au(1 1 1) studied by scanning tunneling microscopy

The self-assembly of ω-ferrocenylalkanethiols (FcCnSH) with different alkyl-spacer lengths on Au(1 1 1) substrates has been studied by scanning tunneling microscopy (STM). Upon deposition at room temperature FcCnSH molecules tend to form multilayers, while by thermal treatment monolayer formation, a rearrangement of the molecules and the formation of ordered domains is achieved. The surface structure of the resulting full coverage self-assembled monolayers is resolved with molecular resolution by STM. The ordered monolayer structure of ω-ferrocenylpropanethiol is discussed in comparison with its bulk crystal structure, derived from single crystal X-ray analysis. Based on these results a monolayer structure of ω-ferrocenylalkanethiols with longer alkyl chains closely related to the bulk crystal structure of the shorter alkyl-spacer derivates is suggested. Our results provide detailed insight into the self-assembly of FcCnSH on gold substrates.     

Characteristics of N-doped TiO2 thin films grown on unheated glass substrate by inductively coupled plasma assisted dc reactive magnetron sputtering

N-doped TiO₂ thin films have been deposited on unheated glass substrates by an inductively coupled plasma (ICP) assisted direct current (dc) reactive magnetron sputtering. All films were produced in the metallic mode of sputtering in order to achieve a high deposition rate. The structures and properties of the N-doped TiO₂ films were studied by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, field emission scanning electron microscopy and UV–Vis spectrophotometer. Experimental results show that we can obtain well crystallized N-doped anatase phase TiO₂ thin films at low deposition temperature and at high deposition rate by using the ICP assisted dc reactive magnetron sputtering process. The doping of nitrogen into TiO₂ lattices leads to a smooth shift of the absorption band toward visible light regions.     

基于唾液的拉曼光谱检测进行肝癌诊断的研究

表面增强拉曼光谱技术是近年来快速发展的一种痕量特征标记性物质检测技术, 达到了分子识别水平, 具有很高的灵敏度, 能够精确地分析和了解物质结构和成分。人体唾液中含有大量体征相关的特异性蛋白质和分泌物质。唾液检测具有无创、获取方便、适合开展大规模普查等优点。表面增强拉曼光谱检测技术可以快速地对唾液进行检测, 二者的结合, 有可能成为一种癌症诊断的新方法。本文利用表面增强光谱技术对肝癌患者进行实验研究, 通过对肝癌患者唾液的采集、样品的处理、光谱的采集及光谱分析, 肝癌特异性标记物AFP(alpha fetoprotein)的检测及分析等过程得到肝癌相关特征信息, 表明肝癌患者与正常人的唾液样本分类良好, 灵敏度及特异性较好; 进一步验证了AFP抗原的分子组成, 且AFP抗原的拉曼强度基本随浓度的递增呈递减趋势; 对肝癌患者的唾液样本及AFP抗原的拉曼光谱进行比对分析, 提示利用表面增强拉曼光谱检测唾液有可能诊断早期癌症。     

一种基于流形学习的近红外光谱分析建模方法

近红外光谱分析的重要内容之一是基于校正样品集建立光谱和化学成分或类别之间的回归模型。流形学习是一类新的机器学习方法,它能够揭示出复杂数据的本质维数,提取最重要的特征信息,并用于建立回归或分类模型。文章以近红外光谱为研究对象,针对近红外光谱数据维数高、谱带归属难以确定等特点,基于流形学习中局部线性嵌入(LLE)算法的思想,提出了一种最小二乘局部加权回归(LS-LWR)建模方法。最后,利用各种浓度葡萄糖溶液的近红外光谱,对该方法进行了验证。同时建立主成份回归(PCR)和偏最小二乘回归(PLSR)模型,通过计算预测标准偏差(SEP)与LS-LWR模型进行比较。实验结果表明,LS-LWR模型有更好的预测效果,而且具有模型简单、稳定性好和计算省时等优点。     

Stable solutions for qq^- bound states with a regularized Breit potential

The Breit interaction contains singular terms which may lead to an instability in quark-antiquark bound state calculations. We regularize the Breit interaction by multiplying the singular terms in momentum space by the form factor μ^2/（q^2＋μ^2） such that the interaction is not singular at the origin and the intermediate-and long-range parts of the interaction remain unchanged. The singular terms in the Breit potential find their stable contributions in the calculations after being multiplied by the form factor with different powers. Such a regularized Breit potential with a linear and a relativistically corrected confining potential are applied to the study of qq^- bound states. The spectra for most familiar mesons are consistently obtained and agree well with the experimental data.     

由单负材料组成的一维对称型光子晶体中的隧穿模

由电单负材料A和磁单负材料B构成了一维对称型光子晶体,数值计算表明其带隙中出现了一隧穿模. 材料层数增加,隧穿模宽度急剧变窄,而其位置不变.隧穿模的位置和宽度对入射角的变化都不太敏感. 材料的几何厚度减小,隧穿模的位置蓝移,而其宽度不变. μ_A, ε_B增加,隧穿模的位置红移,宽度减小. 利用隧穿模的以上特性可以实现对电磁波传播的动态调控.     

Electronic and magnetic properties of Mn-doped ZnO: Total-energy calculations

Based on the spin generalized gradient approximation (σGGA) of the density functional theory (DFT), the structural, magnetic, and electronic properties of Mn-doped ZnO structure have thoroughly been investigated. It is found that the Mn atom prefers to substitute one of the Zn atoms, producing the energetically most stable configuration for the Mn-doped ZnO structure. Employing the Hubbard potential within the calculations suggests various changes and modifications to the structural, magnetic and electronic properties of the Mn-doped ZnO. Our calculations reveal that the local magnetic moment at the Mn site using the ordinary σGGA functional is 4.84 μ_B/Mn, which is smaller than that evaluated by including the Hubbard potential of 5.04 μ_B/Mn. Overall, the electronic band structure of the system, within the σGGA+U, is half-metallic, with metallic nature for the majority state and semiconducting nature for the minority state. Simulated scanning tunneling microscopy (STM) images for both unoccupied and occupied states indicate siginficant brightness on both Zn and Mn atoms and much brighter protrusions around the O atoms, respectively.