一种基于抽取LMS的距离旁瓣抑制方法

在噪声雷达中，传统相关处理方法的距离旁瓣受到时宽带宽积的限制，在有限相关处理时间内得到的距离旁瓣较高，会造成微弱目标被强目标、杂波旁瓣淹没的现象。提出一种基于抽取最小均方（Least Mean Square,LMS）滤波的噪声雷达旁瓣抑制方法，将LMS滤波器的系数作为距离压缩结果，从而获取较低的距离旁瓣。对该方法的性能进行了理论分析，并通过数字仿真验证了算法的有效性和理论分析的正确性。     

Annealing temperature-dependent structural and electrical properties of (Ta2O5)1-x - (TiO2)x thin films,x ≤ 0.11

(Ta₂O₅)_1-x- (TiO₂)_x (TTO_x) thin films, with x = 0, 0.03, 0.06, 0.08, and 0.11, were deposited using magnetron direct current (DC) sputtering method onto the P/boron-silicon (1 0 0) substrates by varying areas of Tantalum and Titanium metallic targets, in oxygen environment at ambient temperature. The as-deposited thin films were annealed at temperatures ranging from 500 to 800 °C. Generally, the formation of the Ta₂O₅ structure was observed from the X-ray diffraction measurements of the annealed films. The capacitance of prepared metal– oxide– semiconductor (MOS) structures of Ag/TTO_x/p-Si was measured at 1 MHz. The dielectric constant of the deposited films was observed altering with varying composition and annealing temperature, showing the highest value 71, at 1 MHz, for the TTO_x films, x = 0.06, annealed at 700 °C. With increasing annealing temperature, from 700 to 800 °C, the leakage current density was observed, generally decreasing, from 10^?5 to 10^?8 A cm^?2, for the prepared compositions. Among the prepared compositions, films with x = 0.06, annealed at 800 °C, having the observed value of dielectric constant 48, at 1 MHz; and the leakage current density 2.7 × 10^?8 A cm^?2, at the electric field of 3.5 × 10⁵ V cm^?1, show preferred potential as a dielectric for high-density silicon memory devices.     

基于混合模式快速电荷平衡的神经刺激器

设计实现了一种可用于脊髓神经刺激器的多通道大电流神经刺激器。提出将电极短接和插入短电流脉冲相结合的混合模式,在大电流下,能更加快速地实现电荷平衡。电路设计上,将ADC动态比较器的回踢噪声消除技术应用于神经刺激器,使得动态比较器在输入压差较小时能够输出正确的比较结果,从而将电极上残留电压保持在更安全的范围内。基于CSMC 0.25 μm BCD工艺进行设计与仿真,结果表明,在单向且最大刺激电流为4 mA、刺激脉宽为60 μs、刺激周期为750 μs的条件下,该15 V、16路神经刺激器能实现±50 mV安全电压的有源电荷平衡。     

瞬变电磁井间勘探的全空间几何因子

井间是剩余油的主要分布区域,为探测井间剩余油,提高采收率,提出了基于全空间几何因子的瞬变电磁井间勘探方法。在本井使用线圈发射、邻井使用线圈接收,根据瞬变电磁场理论,在阶跃信号的激励下发射线圈在地层中激发出沿圆周方向的闭合瞬变电场,该电场在导电地层中产生与地层电导率呈正比的涡流。由Doll地层环模型可知,地层中的涡流在空间任意点激发得到与地层电导率成正比的二次场响应信号(有用信号),并可表示为空间各点电导率的加权平均值,其权重即为井间瞬变电磁勘探的全空间几何因子;全空间几何因子集中分布在发射线圈和接收线圈附近,其它区域分布较少,在发射线圈和接收线圈两侧呈现不同的极性;对瞬变电磁响应与地层电导率、井间距和源距的变化规律研究可知,瞬变电磁井间勘探有用信号随着地层电导率的增大而增大,随着井间距的增加单调减小,在发射线圈和接收线圈处于同一深度时该响应信号幅度最大。     

基于信息熵抑制的大数据特征隐匿性加密仿真

针对传统大数据特征加密方法中大数据精度较差、加密耗时较长的问题,提出基于信息熵抑制的大数据特征隐匿性加密方法。分析信息熵抑制相关理论,采用信息熵映射函数对大数据分类,将信息熵抑制过程转化为计算2个文件相似性的过程,并根据余弦相似度公式以及Hamming距离值计算数据相似度,完成数据消冗。在完成数据消冗的基础上,分析分组密码方法和ECC加密方法,结合两种方法得到大数据特征隐匿性加密处理计算公式,实现基于信息熵抑制的大数据特征隐匿性加密。实验研究结果表明,所提方法能够有效去除冗余数据,提升大数据精度,加快数据加密的处理速度,高效完成大数据加密过程。     

浅谈不同给液方式在铜电解车间的应用

不同给液方式对铜电解过程中有重要的影响,不同的循环方式会影响槽内温度分布、电解液成分及阳极泥沉降等,因此,根据铜电解生产不同情况的需要,分析对比了多种给液方式在贵冶电解车间的应用,总结了这几种给液方式的优缺点和适用条件。     

Design and characteristics of a new type laminar plasma torch for materials processing

Laminar plasma jet(LPJ) generated by laminar plasma torch(LPT) has a favorable temperature and velocity distribution. Thus, it is superior to the turbulent plasma jet in material processing.However, most of the reported LPTs usually operate at a relatively low output power with a relatively low arc voltage and thermal efficiency, which limits its capabilities. In this context, this paper attempts to design a new type of high-power LPT with a relatively low arc current and a high thermal efficiency. In the first section, the design principle of the main components is studied and discussed in detail, and a new high-power LPT is proposed. Then, the experimental characteristics of the proposed high-power LPT are examined. Experimental results reveal the following characteristics of the proposed LPT.(1) The max jet length of the proposed LPT reaches at 540 mm.(2) Its mean arc voltage is higher than 290 V when the LPT works with arc currents lower than 200 A, leading to an output power greater than 50 kW.(3) The mean thermal efficiency is higher than 50%. Lastly, the proposed LPT has been applied to spheroidize the aluminum oxide powers. The experiment results for the production of spherical powders show that the proposed LPT has a good characteristic for material processing.     

Mutual influences of a chemical reaction and thermal radiation on a peristaltic pump of synovial nanofluids in a 3D tapered asymmetric channel

This investigation discusses the influences of a chemical reaction and concentration‐dependent viscosity on a magnetohydrodynamics peristaltic pump of synovial nanofluid in a tapered channel. Chemical reaction and Hall current effects are considered in the proposed investigation. The current study is solved for two suggestion models. In Model‐(I), the concentration is considered as a function in viscosity. In Model‐(II), concentration is considered as a function of the shear‐thinning index. The related study is rearranged under the models of low Reynolds number and long wavelength. The system study of highly nonlinear partial differential equations is explained mathematically with the aid of ParametricNDSolve by using Mathematica 11. Both models have been compared numerically and a huge difference is found between them. Results for velocity profile, temperature, and nanoparticle concentration distributions are obtained graphically for similar values of various physical parameters in three‐dimensional forms. Furthermore, a trapping bolus sketch is proposed in the terminus. The results confirm that the AJ patients can be cured by using the magnetic field in the presence of an electrically inducing influence, as a result of the effort of the ions inside the cell, which accelerates the metabolism of fluids. In addition, maximum values of velocity can control the friction between the joints and thus reduce arthritis.     

Effects of stray AC on corrosion of 3-layer polyethylene coated X70 pipeline steel and cathodic delamination of coating with defects in 3.5 wt-% NaCl solution

In this work, the effects of stray alternating current (AC) on the corrosion of coated X70 pipeline steel and the delamination of 3-layer polyethylene (3PE) coatings with defects were investigated using COMSOL Multiphysics simulation, electrochemical impedance spectroscopy and three-dimensional (3D) digital microscope techniques. The results showed that under the same level of AC interference, pits with deeper maximum pit depth were observed at the smaller defect areas than those at larger defect areas. It was consistent with the simulation results that a greater corrosion current density was accompanied on samples with smaller defects. According to 3D digital images, the larger delamination of 3PE coatings was found on samples with smaller defects. With the increase of current density, the impedance of samples with small defects decreased, while that of samples with large defects increased. Additionally, with the same defect size, the maximum pit depth became deeper and the corrosion was more severe.