用扰动方程研究可压缩边界层中扰动的演化

本文对传统的可压缩流动中的通量分裂方法进行了修正，使其可以用于扰动方程的计算。利用这一方法，对来流马赫数Ma为4．5、雷诺数Re为10^5的可压缩平板边界层中扰动的演化进行了数值模拟。对于给定的基本流，在计算域入口加入T-S波扰动，研究扰动的空间发展演化。对于小幅值的扰动，计算得到的扰动幅值演化和扰动法向分布与线性稳定性理论的结果符合的很好。对于有限幅值的扰动，结果表明，各次谐波无论幅值还是扰动分布都与完整的Navier-Stocks方程计算的结果符合的很好，但由扰动方程得到的平均流修正比N-S方程得到的大一些，这也许是由于在N-S方程计算时，基本流与零阶谐波一起计算而产生的误差所至。     

基于背景重建的序列图像车辆目标检测方法

针对静态摄像条件下视频序列图像,提出一种基于背景重建的序列图像车辆目标检测方法.该法先选取一帧图像存入背景缓冲区,然后根据当前帧图像与前一帧图像、背景图像的差分信息对背景缓冲区的背景进行更新.通过运动区域检测、噪声去除、连通单元标记、目标提取、阴影检测等处理,能获取完整的车辆目标区域.实验结果表明,该方法快速、准确,具有较好的实用价值.     

图像分辨率对天然纤维识别的影响

针对低分辨率图像的保真问题,提出基于轮廓曲线的邻域方向差分链码,进行曲线失真程度的分析.该方法将基于像素坐标的二维轮廓曲线转化成相对于曲线走向而变化角度函数.差分链码具有平移、拉伸和旋转不变性.根据差分链码提出分别针对于对象轮廓周长、轮廓包围面积和轮廓曲线相似性的误差统计模型,并将该模型应用于棉麻等纤维截面的显微图像在不同分辨率下外形的失真度分析,给出在图像采集时允许的最低图像分辨率的计算.     

关于一类非线性偏微分方程的异宿轨及其行波解

一大类非线性偏微分方程都存在行波解,此时这类偏微分方程能转化为相应的常微自治系统。讨论这类偏微分方程的常微定性结构,同时给出它们的显式行波解。     

Study on crustal, lithospheric and asthenospheric thickness beneath the Qinghai-Tibet Plateau and its adjacent areas

Based on the results of pure dispersions of Rayleigh wave tomography in the Qinghai-Tlbet Plateau and its adjacent areas, tsklng S wave velocities from previous linear inversion as the initial model, using the simulated annealing algorithm, a nonlinear simultaneous inversion has been carried out for S wave velocity and thickness of different layers, including the crust, the lithosphere and the asthenosphere. The results indicate： The crustal thickness shows strong correlation with geology structures sketched by the sutures and major faults. The crust is very thick in the Qinghal-Tibet Plateau, varying from 60 km to 80 kin. The Ilthospherlc thickness in the Qinghai-Tibet Plateau Is thinner （130-160 kin） than Its adjacent areas. And two blocks can be recognized, divided by an NNE strike boundary running between 90°E-92°E inside the plateau. Its asthenosphere is relatively thick, varies from 150 km to 230 kin, and the thickest area is located in the western Qiangtsng. India has a thinner crust （32-38 kin）, a thicker lithosphere of 190 km and a rather thin asthenosphere of only 60 kin. Sichuan and Tarlm basins have the crust thickness less than 50 kin. Their Iithospheres are thicker than the Qinghai-Tibet Plateau, and their asthenospheres are thinner. A discussion has been made on the character and formation mechanism of the typical crust-mantle transition zone in the western Qiangtsng block.     

The experimental study of interaction between shock wave and turbulence

The interaction between shock wave and turbulence has been studied in supersonic turbulent mix layer wind tunnel. The interaction between oblique shock wave and turbulent boundary layer and the influence of large vortex in mix layer on oblique shock wave have been observed by NPLS technique. From NPLS image, not only complex flow structure is observed but also time-dependent supersonic flow visualization is realized. The mechanism of interaction between shock wave and turbulence is discussed based on high quality NPLS image.     

试验检测是提高公路工程质量的关键

分析了加强公路工程试验检测工作的必要性和重要性,指出了提高公路工程质量试验检测的措施。     

基于SOM的入侵检测算法的特征选择

针对基于单层SOM神经网络的入侵检测系统计算量大、误报率高的问题,利用SOM网络中相似模式激活神经元的物理位置邻近的特点,根据输入模式的类型,对激活的神经元进行划分,并把记录的基本特征和推导特征结合起来,对记录进行分类.研究结果表明,较小的特征子集能使系统更快地对数据进行分类,与传统的利用单层SOM神经网络方法相比,该方法计算量小、误报率低.     

基于恒模算法的Hopfield神经网络盲多用户检测算法的研究

将恒模算法与Hopfield神经网络的能量函数相结合,提出了基于连续Hopfield神经网络的盲多用户信号检测算法。     

HPLC测定贵州产知母药材中菝葜皂苷元的含量

实验采用乙醇超声提取样品,HPLC梯度洗脱。菝葜皂苷的理论塔板数为5628,分离度为1.42,拖尾因子为1.01。回归方程为Y=5×106X+610 06,r=0.9990.在0.4~2.0mg/mL之间的线性关系良好。日内和日间精密度的RSD均小于2.0%,重复性试验的RSD为0.6%(n=5),最低检测限为1.0μg/mL,加样回收率为96.5%、94.3%、97.2%,RSD(n=5)分别为2.7%、3.1%、2.6%。