Comments on “Quadratic stabilization of continuous timesystems with state-delay and norm-bounded time-varyinguncertainties”

In the above mentioned paper by Mahmoud-Muthairi (ibid. vol.39 (1994)) a sufficient condition for memoryless stabilization of a class of uncertain linear systems with a variable-state delay and norm-bounded time-varying uncertainties is derived in terms of an algebraic Riccati equation. This Riccati equation depends on several free matrix variables, and a subsequent result in the paper, Theorem 2, states that failure or success of the stabilization algorithm is independent of the selection of these matrix variables. In this paper, we give a counterexample to this Theorem 2 as well as providing a fix     

彩色平板玻璃的色度计算

通过数值分析，运用解析几何原理推导出计算彩色玻璃三个参数（主波长、纯度和亮度）的数学模型，编制出计算程序。利用彩色玻璃的单色光透过率，通过该程序可以快速、准确地计算该玻璃的色度值，鉴定该颜色的质量。     

一种阵列信号超分辨率快速算法

提出了一种阵列信号超分辨率快速算法，并分析了它的收敛速度。这种算法基于协方差矩阵的特征值平移和矩阵的幂迭代，而不需要矩阵求逆。它的收敛速度快，一般只需几次迭代就能收敛，且算法结构简单，易于实现。     

Robust Estimation of Rotation Angles from Image Sequences Using the Annealing M-Estimator

A robust method is presented for computing rotation angles of image sequences from a set of corresponding points containing outliers. Assuming known rotation axis, a least-squares (LS) solution are derived to compute the rotation angle from a clean data set of point correspondences. Since clean data is not guaranteed, we introduce a robust solution, based on the M-estimator, to deal with outliers. Then we present an enhanced robust algorithm, called the annealing M-estimator (AM-estimator), for reliable robust estimation. The AM-estimator has several attractive advantages over the traditional M-estimator: By definition, the AM-estimator involves neither scale estimator nor free parameters and hence avoids instabilities therein. Algorithmically, it uses a deterministic annealing technique to approximate the global solution regardless of the initialization. Experimental results are presented to compare the performance of the LS, M- and AM-estimators for the angle estimation. Experiments show that in the presence of outliers, the M-estimator outperforms the LS estimator and the AM-estimator outperforms the M-estimator.     

Modeling of laser cladding with powder injection

Laser cladding is one of the material additive manufacturing processes used to produce a metallurgically bonded deposition layer. To obtain a high-quality resulting part, a deep understanding of the underlying mechanisms is required. In this article, a mathematical model is developed to simulate the coaxial laser-cladding process with powder injection, which includes laser- substrate, laser-powder, and powder-substrate interactions. The model considers most of the associated phenomena, such as melting, solidification, evaporation, evolution of the free surface, and powder injection. The fluid flow in the melt pool, which is mainly driven by Marangoni shear stress as well as particle impinging, together with the energy balances at the liquid-vapor and the solid-liquid interfaces, are investigated. Powder heating and laser power attenuation due to the powder cloud are incorporated into the model in the calculation of the temperature distribution. The influences of the powder injection on the melt pool shape, penetration, and flow pattern are predicted through the comparison for the cases with powder injection and without powder injection. Dynamic behavior of the melt pool and the formation of the clad are simulated. The effects of the process parameters on the melt pool dimension and peak temperature are further investigated based on the validated model.     

网络环境下的蓄电池智能监测系统设计

介绍了一种新型智能蓄电池监测系统的设计方案，并进一步研究了网络环境下蓄电池监控数据的加工处理，以实现蓄电池监测软计算模型的动态进化。     

汽轮发电机组轴向振动的分析和处理

从轴向振动的机理入手,结合现场试验研究,对汽轮发电机组轴向振动进行了详细的分析,提出了处理解决的方法,实践证明是行之有效的.     

某型内燃机闭环控制减振的仿真研究

内燃机自身的振动是重型军用车辆主要的振动和噪声源,对其进行有效的振动控制十分重要.但由于内燃机系统结构的复杂性,研究其振动和噪声控制比较困难.针对某型内燃机系统,采用Matlab软件的Simulink工具,建立了整个系统的动力学仿真模型,并分别对该模型进行简谐、白噪声信号扰动下的减振控制研究,控制方法采用闭环数字PI策略.系统输出转矩和转速的曲线结果表明减振具有明显的效果.     

理论研究方法在膜超(微)滤研究中的应用

在对超(微)滤的过滤性能及过程的研究中，实验研究作出了很多贡献，但实验研究存在着结论对具体实验体系有很大依赖性、研究费用较高等缺点．介绍几种较经典的扩散模型和流体动力学模型及其建模思路、适用范围和存在问题；提出借助理论分析和计算方法设计实验，再根据实验数据利用人工神经网络建立普用性模型的新方法、对于方程的求解，介绍了简化法、摄动法、数值计算与模拟等方法的特点及其在超(微)滤研究中的应用，认为用数值计算的方法研究超(微)滤机理及膜器优化设计必将成为今后超(微)滤研究的重要方向之一．     

预制挑檐的几种构造作法

挑檐是建筑屋面的一个组成部分。本文介绍了挑檐自重平衡法、屋面板压重平衡法、圈梁压重平衡法、螺栓锚固法等四种预制挑檐的构造 ,在施工过程中应根据现场环境合理选用