斜射法应力分离计算方法的研究

光弹性实验获取的数据,只给出了构件内部任意一点的主应力差值及其方向。为求取平面应力的三个分量,还需要建立补充方程进行应力分解。使用斜射法计算应力分量时,考虑到实验获取数据不精确的特点,可以采用多角度斜射,构成非线性超定方程组求解应力分量。传统方法对于非线性超定方程组的求解较为困难,将非线性超定方程组叠加,改为求最小绝对值,可以使用粒子群算法求解应力分量。通过计算机仿真径向受压的圆盘,选取10个斜射角度,建立方程组求出应力分量,验证了粒子群算法的可行性,得到了满意的仿真实验结果。

基于斜射式散射法的曲表面粗糙度原理及其系统研究

针对狭小空间曲表面粗糙度测量精度与效率不足的问题,对光源斜射入狭小空间曲表面形成的空间散射强度信号分布与曲表面粗糙度值之间的关系进行了研究,提出了一种基于斜射式散射法的光纤传感器粗糙度测量系统。首先通过实验构建了测量电压值与光入射角度、传感器与曲表面测量距离及曲表面曲率等参数之间的特性曲线,确定了该系统的测量范围;其次通过标定实验获得了粗糙度值和测量电压值的特性曲线,该特性曲线与理论分析结果相吻合,且呈单调性;最后利用该系统进行了狭小空间曲表面粗糙度的测量实验。研究结果表明,该方法具有一定的可行性,与触针法所获结果之间的误差小于5%,能够进行狭小空间曲表面粗糙度测量。

光弹性贴片法全场分离主应变方法研究

本文介绍一种全场分离光弹性贴片法中主应变的方法,利用光测数字图像分析系统实现了数据的自动采集与处理。

K_1、K_2、K_3混合型裂纹问题的光弹性方法求解

导出了用光弹性斜射法求 K_3的理论公式,在此基础上,结合超定法,用一次切片,解决了 K_1、K_2、K_3的混合型裂纹问题的光弹性方法求解,并进行了实验验证.

光学式非接触厚度-微位移测量仪的研制

在激光三角测量法原理基础上,应用光学系统成像技术,利用光电位置传感器PSD获得象点移动量,并根据象点移动量建立与被测物厚度—微位移变化之间的数学模型,通过象点位置变化的计算,研制了光学或非接触厚度—微位移测量仪。实现了被测物厚度—微位移变化量的测量。该测量仪的量程为1000μm,分辨力小于0.2μm。

基于图像处理的带式输送机煤体积计量

对基于激光斜射法三角测距原理的带式输送机上煤流体积实时计量进行了研究。首先对工业相机采集到的激光线进行图像处理以获取煤流截面,根据煤流表面激光线特点提出了一种能够大幅度降低搜索区域的激光线细化算法,并采用线性插值对断线进行连接,通过合成上下轮廓线形成完整煤截面;然后建立了动态煤体积计量模型,通过积分得到煤流体积。最后进行了实验,单帧图像的采集处理时间平均约为0.152 s,且算法稳定性较好,能够满足实际工况要求。

ASME核电用钢板超声波检测结果的对比分析

对ASME核电用钢板进行直射法和斜射法超声检测对比分析,找出了两者之间的一致性与差异性,总结出产生差异的原因主要是由于两种检测方法的灵敏度差异以及被检缺陷的大小、位置、取向和形状等因素。考虑到核电用钢的特殊性,要求同时采用斜射法与直射法对钢板进行检测,防止缺陷漏检,严把出厂产品质量关。

Influence of alkylpyridinium ionic liquids on copper electrodeposition from acidic sulfate electrolyte

The effect of two alkylpyridinium ionic liquids （py-iLs） including N-butylpyridinium hydrogen sulfate （BpyHSO4） and N-hexylpyridinium hydrogen sulfate （HpyHSO4） on the kinetics of copper electrodeposition from acidic sulfate solution was investigated by cyclic voltammetry and potentiodynamic polarization measurements. Results from cyclic voltammetry indicate that these py-iLs have a pronounced inhibiting effect on CuE＋ electroreduction and there exists a typical nucleation and growth process. Kinetic parameters such as Tafel slope, transfer coefficient and exchange current density obtained from Tafel plots, lead to the conclusion that py-iLs inhibit the charge transfer by slightly changing the copper electrodeposition mechanism through their adsorption on the cathodic surface. In addition, scanning electron microscope （SEM） and X-ray diffraction analyses reveal that the presence of these additives leads to more leveled and fine-grained cathodic deposits without changing the crystal structure of the electrodeposited copper but strongly affects the crystallographic orientation by significantly inhibiting the growth of （111）, （200） and （311） planes.

EFFICIENT GRADIENT DESCENT METHOD OFRBF NEURAL ENTWORKS WITHADAPTIVE LEARNING RATE

A new algorithm to exploit the learning rates of gradient descent method is presented, based on the second-order Taylor expansion of the error energy function with respect to learning rate, at some values decided by "award-punish" strategy. Detailed deduction of the algorithm applied to RBF networks is given. Simulation studies show that this algorithm can increase the rate of convergence and improve the performance of the gradient descent method.

Three-dimensional Scattering of Obliquely Incident Plane SH Waves by an Alluvial Valley in a Layered Half-space

The indirect boundary element method （IBEM） is used to study three-dimensional scattering of obliquely incident plane SH waves by an alluvial valley embedded in a layered half-space. The free-field response of the layered half-space is calculated by the direct stiffness method, and dynamic Green＇s functions of moving distributed loads acting on inclined lines in a layered half-space are calculated to simulate the scattering wave field. The presented method yields very accurate results since the three-dimensional dynamic stiffness matrix is exact and the moving distributed loads can act directly on the valley boundary without singularity. Numerical results and analyses are performed for amplification of obliquely incident plane SH waves around an alluvial valley in a uniform half-space and in single layer over half-space. The results show that the three-dimensional responses are distinctly different from the two-dimensional responses, and the displacement amplitudes around alluvial valleys in a uniform haft-space are obviously different from those in a layered half-space.

小径厚壁无缝钢管的超声波周向接触法检测

国内外无缝管材的超声波检测标准和检测技术在薄壁管的检测应用方面相对比较明确,而对于厚壁管的检测还没有特别明确的方法。本文主要论述了通过修磨探头,利用变型波法检测小径厚壁管的超声波检测技术,并在工程项目中取得了良好的实际应用效果。

Synthesis of monoclinic structure gallium oxide film on sapphire substrate by magnetron sputtering

Gallium oxide （Ga203） films were deposited on singlecrystalline sapphire （0001） substrate by radio frequency （RF） magnetron sputtering technique in the temperature range of 300--500 ℃. The microstructure of the fl-Ga203 films were investigated in detail using X-ray diffractometer （XRD） and scanning electron microscope （SEM）. The results show that the film prepared at 500℃ exhibits the best crystallinity with a monoclinic structure （fl-Ga203）. Structure analysis reveals a clear out-of-plane orientation offl-Ga203 （201） II A1203 （0001）. The average transmittance of these films in the visible wavelength range exceeds 90%, and the optical band gap of the films varies from 4.68 eV to 4.94 eV which were measured by an ultraviolet-visible-near infrared （UV-vis-NIR） spectrophotometer. Therefore, it is hopeful that the fl-Ga203 film can be used in the UV optoelectronic devices.