Spectral Integral Variations of Degree Maximal Graphs

The concept of the spectral integral variation was introduced by Fan [Fan Yizheng (2002). On spectral integral variations of graphs. Linear and Multilinear Algebra , 50 , 133-142] to study the general graphs with all changed eigenvalues moving up by integers when an edge is added. Here we consider the spectral integral variations of maximal graphs G , and successfully give an equivalent condition for the spectral integral variation of G occurring in two places by adding an edge e . We also characterize whether the graph G + e is maximal so that an explicit interpretation of the above condition is obtained, where G + e denotes the graph obtained from G by adding an edge e .     

Space tests of relativistic gravity with precision clocks and atom interferometers

Precision clocks and interferometers in space can test relativistic gravity with extremely high sensitivity. Yet, only a single such test has been performed, namely the celebrated flight of a hydrogen maser in a sub-orbital trajectory in 1976 (GP-A mission). This paper suggests some of the obstacles to space flight of precision instruments, and describes how the emergence of new technology might offer a pathway for removing those obstacles. A brief review of emerging technologies is made, and new mission concepts based on them are described. Some of the technologies that can impact more tests of relativistic gravity in space at a more distant future are also described.     

Generating the patterns of variation with GeoGebra: the case of polynomial approximations

In this paper, we report a teaching experiment regarding the theory of polynomial approximations at the university mathematics teaching in Sweden. The experiment was designed by applying Variation theory and by using the free dynamic mathematics software GeoGebra. The aim of this study was to investigate if the technology-assisted teaching of Taylor polynomials compared with traditional way of work at the university level can support the teaching and learning of mathematical concepts and ideas. An engineering student group (n = 19) was taught Taylor polynomials with the assistance of GeoGebra while a control group (n = 18) was taught in a traditional way. The data were gathered by video recording of the lectures, by doing a post-test concerning Taylor polynomials in both groups and by giving one question regarding Taylor polynomials at the final exam for the course in Real Analysis in one variable. In the analysis of the lectures, we found Variation theory combined with GeoGebra to be a potentially powerful tool for revealing some critical aspects of Taylor Polynomials. Furthermore, the research results indicated that applying Variation theory, when planning the technology-assisted teaching, supported and enriched students’ learning opportunities in the study group compared with the control group.     

成人血清元素相关性及比值分析

用ＩＣＰ－ＭＳ法测定了７９例成人血清１４种元素水平,并进行了相关分析。结果提示,多种元素间存在显著正相关;分析了部分元素的比值,为相关研究提供了参考范围,且对元素比值的离散程度进行分析,为多元素关系研究提供了新的线索与依据。     

指纹紫外光谱特性研究及变化规律分析

指纹的唯一性和终身不变性使得指纹可以验证一个人的身份信息,在生物识别领域具有广泛的应用。汗潜指纹对紫外线有着特殊的反射、散射以及荧光特性,所以可以利用紫外波段对汗潜指纹进行提取,并且不污染现场和目标样本。目前对紫外波段的指纹提取已经有着广泛的研究,但对指纹随时间变化的研究较少,一般都是通过化学方法测量汗潜指纹成份含量的变化。研究发现,指纹各个组成成份的紫外光谱特性不同,且这些成份随时间的挥发程度也不一致,利用多通道紫外成像系统对汗潜指纹进行凝视成像,发现各通道成像DN值随时间推移的变化程度并不一样,可通过研究各通道DN值的变化对指纹进行时间分析。首先,利用紫外光谱仪和氙灯,对汗液、酒精、食用油等几种手指容易接触的物质的反射光谱进行研究,得到了这些物质的反射光谱特性。然后,针对这几种类型的指纹,研制了一套多通道紫外成像设备,分别在240~280 nm（通道1）、280~315 nm（通道2）以及315~340 nm（通道3）三个紫外通道对其进行凝视成像,得到清晰的指纹图像,将指纹图像嵴线上码值最高的10个点的平均值进行比较,得到不同通道DN值与时间变化的关系。实验结果发现,汗潜指纹在紫外波段具有良好的成像特性,其成像DN值随时间的推移逐渐降低,其中240~280 nm的通道1中三个指纹在第七天的成像DN值分别降为第一天的0.62, 0.60和0.59;320~340 nm的通道2中三个指纹在第七天的成像DN值分别降为第一天的0.57, 0.61和0.60;340~420 nm的通道3中三个指纹在第七天的成像DN值分别降为第一天的0.56, 0.63和0.58。实验结果表明,不同类型的指纹在紫外波段的光谱特性并不一致,成像DN并不相同,且随时间的变化规律也不一样,但指纹成份的挥发具有一定的规律,成像DN值从第一天到第七天降低至60%左右,可以一定程度上反映指纹的挥发性质。结合紫外多通道成像系统,可以很好的研究指纹的变化规律,为刑侦探测中指纹研究提供了一个重要的手段。     

Complexity of Gaussian-radial-basis networks approximating smooth functions

Complexity of Gaussian-radial-basis-function networks, with varying widths, is investigated. Upper bounds on rates of decrease of approximation errors with increasing number of hidden units are derived. Bounds are in terms of norms measuring smoothness (Bessel and Sobolev norms) multiplied by explicitly given functions a(r,d)$a(r,d)$ of the number of variables d$d$ and degree of smoothness r$r$. Estimates are proven using suitable integral representations in the form of networks with continua of hidden units computing scaled Gaussians and translated Bessel potentials. Consequences on tractability of approximation by Gaussian-radial-basis function networks are discussed.     

改进的盲解卷积技术在远距离激光光斑图像复原中的应用

为了提高外场实验中远距离测量激光光斑位置的精度,提出利用盲解卷积技术对光斑图像进行事后复原来削弱大气湍流对光斑成像的影响。首先,介绍了经典盲解卷积算法,分析了其不足之处,并提出了一种改进的盲解卷积算法。为了提高目标函数的收敛性和收敛速度,在TV(Total Variation)目标函数加入惩罚项,并对交替迭代法进行改进。然后,用数学方法证明了改进的盲解卷积算法的收敛性。最后,进行了仿真实验。与传统算法相比,用改进算法恢复的图像信噪比至少提升了15%。文中给出了外场试验图像的实际复原效果。     

梁山慈竹微纤丝角的X射线衍射技术解析及对拉伸力学的影响

采用X射线衍射技术对梁山慈竹微纤丝角(MFA)的变异特性进行了研究,并就微纤丝角对拉伸力学的影响进行了分析。结果表明,梁山慈竹微纤丝角随竹龄增加的变化较小,三年生竹的微纤丝角最大,为8.521°,二、三年生竹微纤丝角的平均值明显大于四、五年生竹,差异绝对值小于0.1°。竹秆基部、中部和上部微纤丝角的平均值分别为8.499°,8.497°和8.483°,变异系数在5%左右。微纤丝角从竹青到竹黄呈增大的趋势。方差分析表明,径向部位对微纤丝角有显著性影响,竹龄和纵向部位对微纤丝角无显著影响。顺纹拉伸强度和杨氏模量呈线性相关(r=0.57)。微纤丝角对力学性能有一定影响,拉伸强度和杨氏模量中分别有35%和43%的变异由微纤丝角引起。