关于凸函数的新不等式

考虑由Fejér不等式的右边部分生成的差值.通过建立积分恒等式,在导函数满足M-Lipschitz条件和导函数有界这两种情况下,给出这个差值的界的估计.     

基于微波光子学的准分布式光纤传感解调技术

准分布式光纤传感系统在土木工程、能源勘测、航空航天、国防、化工等领域一直发挥着不可替代的重要作用。以微波光子学为基础的准分布式光纤传感解调技术被广泛应用于光纤复用系统的快速、高精度的信号解调与传感器定位。与传统的光学波长解调方案相比,该技术大幅提高了系统的解调速率,弥补了传统解调方法在传感器定位方面的缺陷。本文主要介绍了近年来国内外在基于微波光子学的准分布式光纤传感解调领域的研究进展,从光纤光栅准分布式传感系统和光纤法布里-珀罗准分布式传感系统两方面入手,对比分析了现有的数种微波解调光纤准分布式系统的优缺点,并对基于微波光子学的准分布式光纤传感解调技术的未来发展方向进行了总结与展望。     

Lagrange插值和Hermite-Fejér插值在Wiener空间下的平均误差

在L_q-范数逼近的意义下,确定了基于Chebyshev多项式零点的Lagrange插值多项式列和Hermite-Fejér插值多项式列在Wiener空间下的p-平均误差的弱渐近阶.从我们的结果可以看出,当2≤q<∞,1≤p<∞时,基于第一类Chebyshev多项式零点的Lagrange插值多项式列和Hermite-Fejér插值多项式列的p-平均误差弱等价于相应的最佳逼近多项式列的p-平均误差.在信息基计算复杂性的意义下,如果可允许信息泛函为计算函数在固定点的值,那么当1≤p,q<∞时,基于第一类Chebyshev多项式零点的Lagrange插值多项式列和Hermite-Fejér插值多项式列在Wiener空间下的p-平均误差弱等价于相应的最小非自适应p-平均信息半径.     

利用具有相位跳跃技术的阴影摩尔图测量电子组装元件的热翘曲

Phase-stepping technique is applied to the analysis of fringe patterns of shadow moiré of electronic packages.Sensitivity of the fringe pattern analysis is demonstrated to be significantly increased.Thermally induced warpage of electronic packages is successfully measured in real-time as the sample is driven through a simulated reflow process.The paper discusses the technique of phase stepping,noise filtering and its application to the shadow moiré method.Applications of the technology are presented.     

Development of a machine integrated strain-based contact force sensor for pad foot soil compactors

An investigation was undertaken to explore the use of measurable pad strains on a non-vibratory pad foot roller to provide real time continuous evidence of compaction and contact force. Individual pads were instrumented with strain gages in a pattern chosen based on pad finite element analysis (FEA). Different pad–soil contact stress distributions were modeled to simulate a range of soil conditions. The FEA revealed that the contact stress distribution has a significant influence on the observed pad strain field, suggesting soil specific interpretation of pad strains in order to determine contact force. Results from uniaxial laboratory testing of pad loading on dry sand verified the FEA, i.e., experimental strains generally matched within 15% of FEA strains. The contact stress distribution was measured using tactile pressure sensors and found to be moderately parabolic. A soil specific empirical calibration factor relating vertical sidewall strains to contact force was determined. Field testing was performed on the dry sand with multiple instrumented pads installed on a Caterpillar CP56 roller. Pad strain magnitudes increased up to 250% during compaction from repeated passes of the roller. Using the empirical calibration factor, the estimated contact force was shown to increase with compaction, represented by the independently-measured soil unit weight.     

非线性椭圆边值问题和极大单调算子的零点

本文利用非线性极大单调算子值域的扰动结论,研究一类与广义p-Laplacian算子相关的、具Neumann边值条件的非线性椭圆方程的解的存在唯一性.同时研究这个唯一解与适当定义的非线性极大单调算子的零点之间的关系.进而设计一种迭代算法强收敛到这个唯一解.本文采用新的构造算子和拆分方程的方法,推广和补充了以往的相关研究工作.     

任意相移阴影叠栅相位解调技术的研究

结合时域和频域干涉图分析方法,提出一种任意相移阴影叠栅条纹图相位解调技术,降低了干涉图在采样过程中对相移量的严格标定要求,补偿了相移阴影叠栅技术固有的相移不匀误差。使用空域技术确定采样干涉图的正交信号,进而得到了采样干涉图的相移量,然后运用任意相移相位提取算法搜索测量相位信息。实验证明此方法简单方便、求解迅速,且优于典型的相移算法,其测量误差的标准差不超过3×10-3 mm,该方法为提高相移阴影叠栅技术的测量精度提供了有效手段。     

带两个形状参数的五次Bézier曲线的扩展

给出了一组含有两个形状参数α,β的六次多项式基函数,是五次Bernstein基函数的扩展,分析了这组基的性质;基于这组基定义了带两个形状参数的多项式曲线,所定义的曲线具有五次Bézier曲线的性质,改变参数α,β的取值,曲线具有更灵活的形状可调性,而且能向上或从两侧逼近控制多边形.另外,经典的五次Bézier曲线和有关文献中带一个形状参数的曲线均是该文所定义曲线的特例.实例表明,定义的曲线为曲线/曲面的设计提供了一种有效的方法.     

An L 2-theory for a class of SPDEs driven by Lévy processes

In this paper we present an L 2-theory for a class of stochastic partial differential equations driven by Lévy processes.The coefficients of the equations are random functions depending on time and space variables,and no smoothness assumption of the coefficients is assumed.     

二元齐次矩阵Pad-型逼近及误差公式

二元矩阵Pade-型逼近的计算比较复杂.本文受Benouahmane和Cuyt的启发,通过引入一种变量代换,将二元齐次矩阵形式幂级数转化为一元含参数形式的矩阵形式幂级数,并给出了二元齐次矩阵Pade-型逼近的构造性的定义和误差公式的证明.数值实例说明了此方法的有效性.