二维相干技术在微弱信号检测中的应用

相干技术是一种利用数学方法突出相邻道之间信号的相似性，进而达到检测微弱信号、反映异常特征的一项新技术．本文在对相干计算的数学模型实现方法进行探讨的基础上，开发了一套相干技术的应用软件．并对理论模型和实际模型进行处理，取得了显著的应用效果．通过理论模型及实际模型的试验说明该方法是一种行之有效的微弱信号检测方法．     

拟协调有限元

拟协调元出现20多年了,已被承认和采用.本文从广义方程出发,主要陈述弱形式弹性力学基本方程是拟协调元的内在本质,揭示最小势能原理可由弱形式派生出来,指出用弱形式表达的平衡条件既有微分方程也有边界条件,可看成是变分的出发点,是更根本和原始的条件.因此变分解也是一种弱形式解,进而说明拟协调元是有限元发展的必然趋势.     

Some New Views on the Principles of Magnetron Sputtering

In this paper, some common phenomena in magnetron sputtering are freshly analyzed and discussed on the basis of the motion of electrons in non-uniform orthogonal electric and magnetic fields. There exist magnetic confinements in three spatial dimensions on moving charged particles (including electrons) in this kind of non-uniform field. They are the longitudinal cycloidal motion, the horizontal simple harmonic-like motion (with varying amplitudes), and the vertical repelling action. The horizontal magnetic confinement in a mirror-like magnetic field keeps glow discharge lane completely parallel to the corridor of magnetic force lines, therefore only an effectively closed magnet array structure can form a relatively uniform and closed discharge lane. The main reasons for electrons' releasing from magnetic confinement are the vertical magnetic repelling force as well as a more and more weak confinement action in outer range etc. The dominant reasons for a comparatively low increase of substrate's temperature are that the density of bombarding electrons near the substrate is relatively low and their spatial distribution is relatively uniform (compared with that near the target surface). The erosion lane with an inverted Gauss's distribution shape on a magnetron sputtered target is due to that,with sputtering, the distribution width of the critical density of electrons shrinks continuously but the sputtering effect in the centerline of the corridor is always the most powerful.     

宋农水电站混凝土重力坝断面优化设计

由于层次多、倾角缓、抗剪强度较低的泥化夹层或破碎夹层广为分布,故宋农水电站混凝土重力坝基础沿缓倾角软弱夹层的深层滑动是大坝抗滑稳定要控制的重点。经多方案比较,最终采用了坝体上游设置防渗板的处理方案。该方案不仅满足了坝体强度及稳定要求,而且使坝体工程量减少了26%,且加大了溢流坝的泄流能力。此方案是较为经济安全的处理办法,解决了不良坝基的大坝深层抗滑稳定问题,而且优化了坝体断面体形。     

小波分析在IC IDDT弱故障定位研究中的应用

针对IC中的弱故障进行了瞬态电流IDDT研究,发现IDDT信号中带有弱故障信息,在此基础上应用小波分析技术对弱故障IDDT进行了故障定位研究,提取出电路的故障特征参数Td,为实现弱故障定位进行了有益地探索。     

随机共振技术在弱随机二元码检测中的应用研究

分析了小信号条件下二维双稳Duffing系统的随机共振现象,提出基于Duffing系统随机共振技术的微弱随机二元码检测方法,此方法在不需要知道被检测信号的任何先验知识的条件下,检测微弱随机二元码信噪比可以达到-25dB以下,并可估计出信号波形,计算机仿真验证了该方法的有效性;为强噪声背景下微弱随机二元码的检测提供了一种操作性强、高效的方法。     

耐温抗盐HPAM/Al~(3+)弱凝胶调剖体系的研制及评价

针对深部调剖对化学剂耐高温抗高盐的要求,采用水解聚丙烯酰胺与实验室自制的交联剂和稳定剂以及一些助剂组成耐温抗盐弱凝胶体系。实验表明,该体系能够耐温100℃,抗盐250 g/L[其中ρ(Ca2+)=4 g/L];对高低渗透层的吸水剖面调整能起到明显的作用,高低渗透层的级差越大,则剖面改善效果越明显;在室内实验条件下,该种调剖剂可以较大幅度地提高采收率(平均提高采收率程度为16.1%)。该体系已经在现场调剖施工中成功应用,效果明显。     

Novel weak target detection technique based on time-dimension reduced multiple frame detection in the Radon domain

Low-altitude slow-moving weak target detection in the heavy clutter is a challenging problem for low resolution radar. This paper proposes a time-dimension reduced multiple frame detection algorithm in the Radon domain to solve it. In our framework, adaptive moving target indication (AMTI) and the order statistic constant false alarm rate filter (OS-CFAR) are utilized to suppress the clutter primarily. After resampling and smoothing the combined time-range profiles in the time direction, the Radon transform is applied to this set of new time-range profiles. Then target detection is converted into a problem of feature extraction in the Radon domain, and the moving target can be figured out by two thresholds from the clutter in the parameter domain. Since the differences of skewing angles between the slow-moving targets and clutter in the Radon domain are amplified by time-dimension reduction operator, we can both detect the target and estimate its velocity. Real data demonstrate the effectiveness of the proposed algorithm.     

巴东组第三段含钙质夹层土抗剪强度试验研究

选取三峡库区巴东县巴东组第三段灰岩与泥灰岩间的软弱夹层土为研究对象,通过三轴不固结不排水试验(UU)剪切重塑土样,重点研究夹层土中CaCO₃含量(0%,2%,4%,6%)对其抗剪强度的影响规律。再结合CT扫描试验,观察土样在三轴试验前后的内部孔隙率和胶结程度变化情况,以此作为依据,分析含钙质夹层土的抗剪强度变化机理。最终得出:随着CaCO₃含量的增加,土样抗剪强度增大,这是因为CaCO₃通过降低土体孔隙率和改变土颗粒形态增大了土体的内摩擦角,通过增强土体胶结能力增大了土体的黏聚力,从而增大其抗剪强度。此外,黏聚力的变化受CaCO₃含量的影响更大,而内摩擦角的变化受CaCO₃含量的影响较小。