基于改进的Sage-Husa滤波MEMS陀螺阵列降噪技术研究

为充分挖掘 MEMS 陀螺的性能,提高 MEMS 陀螺在实际应用中的精度,通过搭建四陀螺阵列结合改进的 Sage-Husa 滤波算法对陀螺阵列的输出信号进行降噪,在不改变陀螺加工工艺和显著提高生产成本的条件下有效提高了 MEMS 陀螺仪的实际性能。 通过分析 MEMS 陀螺仪的系统误差和随机误差,搭建误差模型,利用传统卡尔曼滤波、移动平均滤波、小波阈值去噪和改进的 Sage-Husa 滤波算法对单个陀螺和陀螺仪阵列进行降噪处理,实验对比发现改进的 Sage-Husa 滤波算法和陀螺仪阵列结合后能有效降低陀螺的输出噪声。 利用 Allan 方差分析陀螺仪阵列经过改进的 Sage-Husa 算法滤波后的随机误差,四陀螺阵列角度随机游走从 0. 40°/ h降低到 0. 03°/ h ,零偏不稳定性从 71. 11°/ h 降低到 5. 83°/ h,有效提高了 MEMS 陀螺在实际应用中的性能。     

NOVEL BIPHASE CODE——INTEGRATED SIDELOBE SUPPRESSION CODE

A kind of novel binary phase code named sidelobe suppression code is proposed in this paper.It is defined to be the code whose corresponding optimal sidelobe suppression filter outputs the minimum sidelobes.It is shown that there do exist sidelobe suppression codes better than the conventional optimal codes-Barker codes.For example,the sidelobe suppression code of length 11 with filter of length 39 has better sidelobe level up to 17dB than that of Barker code with the same code length and filter length.     

推进剂初始温度影响液体火箭发动机燃烧稳定性的数值模型

对自然推进剂（ＭＭＨ／ＮＴＯ）初始温度对火箭发动机燃烧稳定性的影响进行了研究,从推进剂初始温度对蒸发速率的影响规律出发,发展了初始温度大小影响蒸发速率的物理模型。燃烧流动过程应用圆柱坐标系下的两相湍流化学反应Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程来描述,控制方程是用限体积法在任意曲线坐标系下进行离散,计算采用ＴＭＭ方法生成的正交网格。完善了一种压力隐式算子分裂算法,使之应用到燃烧过程和不稳定燃烧中,提高了计算的精度和稳定性;以蒸发作为燃烧速率控制过程,由ＭＭＨ的分解蒸发速率来控制。用蒸发和分解的时滞来分析燃烧不稳定性。应用ＣＦＤ技术发展了评定燃烧稳定性的脉冲枪模型,之后对推进剂初始温度对燃烧稳定性的影响进行了数值研究,得到其对振荡的敏感分析,并给出燃烧稳定性的极限图,说明了该物理模型和算法的可靠性。     

Temporal and 2-D small-signal gain measurements in a supersonicCOIL

A dedicated CW chemical oxygen iodine mini-laser is constructed and used to probe the two-dimensional (2-D) distribution of small-signal gains in a supersonic CW chemical oxygen iodine laser (CW COIL). The uneven lateral gain distribution may possibly be explained by boundary layer effects     

添加Y2O3的自蔓延高温合成β-Sialon粉的微波烧结

采纳合理的保温结构，利用TE103单模腔微波烧结系统对添加6wt％Y2O3的自蔓延高温合成β-Sialon粉末的微波烧结行为、烧结样品的微观结构和力学性能进行了研究，SEM和TEM、HREM观察表明，烧结样品晶粒细小，微观结构均匀，力学性能测试表明在1600℃保温5min时烧结样品具有抗弯强度为470MPa，断裂韧性为5．0MPa·m－2，洛氏硬度为89．5；在1650℃保温5min时烧结样品具有抗弯强度为630MPa，断裂韧性为5．8MPa·m-2，洛氏硬度为91．6．     

Gaussian mixture density modeling, decomposition, and applications

We present a new approach to the modeling and decomposition of Gaussian mixtures by using robust statistical methods. The mixture distribution is viewed as a contaminated Gaussian density. Using this model and the model-fitting (MF) estimator, we propose a recursive algorithm called the Gaussian mixture density decomposition (GMDD) algorithm for successively identifying each Gaussian component in the mixture. The proposed decomposition scheme has advantages that are desirable but lacking in most existing techniques. In the GMDD algorithm the number of components does not need to be specified a priori, the proportion of noisy data in the mixture can be large, the parameter estimation of each component is virtually initial independent, and the variability in the shape and size of the component densities in the mixture is taken into account. Gaussian mixture density modeling and decomposition has been widely applied in a variety of disciplines that require signal or waveform characterization for classification and recognition. We apply the proposed GMDD algorithm to the identification and extraction of clusters, and the estimation of unknown probability densities. Probability density estimation by identifying a decomposition using the GMDD algorithm, that is, a superposition of normal distributions, is successfully applied to automated cell classification. Computer experiments using both real data and simulated data demonstrate the validity and power of the GMDD algorithm for various models and different noise assumptions.     

溅射功率对CIGS吸收层前驱膜成分和结构的影响

采用中频交流磁控溅射方法制备了CuIn、CuGa和CIG合金膜。采用SEM和XRD观察和分析了各种薄膜的表面形貌、成分和组织结构。着重分析了靶功率密度对薄膜成分、晶体结构的影响。结果表明,通过调节靶功率密度,能精确控制薄膜中CuI、n、Ga比例。制备得到了Cu/(In Ga)原子比接近1,且Ga/(In Ga)比例可调的成分分布均匀的CIG薄膜。CIG前驱膜是以Cu11In9为基础相,Ga原子主要是以替代In原子的固溶体形式存在。当溅射CuIn和CuGa合金靶的功率密度分别为0.26和0.10 W/cm2时,可制备得到由Cu11In9和CuIn两相组成的理想的CIG前驱膜。     

MPEG-2传输流中的时间信息与音视频同步

文中讨论了MPEG 2传输码流中的时间信息 (传输层中的节目参考时钟 ,PES层中的显示时间标签和节码时间标签 )在音视频同步中的作用。对理想解码器中的音频、视频同步原理作出了分析。指出了实际解码器实现视音频同步的困难之处并提出了解决办法。对实际解码中出现的视音频失同步的情况 ,通过对解码器的控制达到重复帧和丢帧的效果 ,从而重新实现了音、视频的同步。     

等离子喷涂Al2O3+13wt%TiO2陶瓷涂层的 激光重熔处理

本文用Ｘ射线衍射、扫描电镜和显微硬度研究了等离子喷涂Ａｌ２Ｏ３＋１３ｗｔ％ＴｉＯ２陶瓷涂层激光重熔处理后陶瓷熔化层的组织结构及硬度变化特征。激光重熔区亚稳相Ｙ－Ａｌ２Ｏ３转变成为稳定相α－Ａｌ２Ｏ３：ＴｉＯ２与Ａｌ２Ｏ３反应生成ＴｉＡｌ２Ｏ３陶瓷熔化层致密,无孔隙、少裂纹或无裂纹;熔化层硬度有较大提高,且随激光能量密度的增大而增大,而涂层设计对其影响很小。此外,激光重熔能极大地提高陶瓷的涂层的耐磨     

Robust face detection and analysis

This paper presents a method which utilizes color, local symmetry and geometry information of human face based on various models. The algorithm first detects most likely face regions or ROIs (Region-Of-Interest) from the image using face color model and face outline model, produces a face color similarity map. Then it performs local symmetry detection within these ROIs to obtain a local symmetry similarity map. The two maps and local similarity map are fused to obtain potential facial feature points. Finally similarity matching is performed to identify faces between the fusion map and face geometry model under affine transformation. The output results are the detected faces with confidence values. The experimental results demonstrate its validity and robustness to identify faces under certain variations.