镀有非对称交替膜系的玻璃颜色特性研究

本文对镀有非对称折射率高低交替膜系的玻璃的颜色特性进行了研究。比较了不同的膜系结构形式,通过改变每层膜的厚度,可得到的不同的色品坐标。发现镀的玻璃上的第一层膜为高折射率材料所得到的玻面颜色好。灾个结论可应用到玻璃装饰业上。     

有关混沌及其控制与同步的一些理解

从实例出发，对非线性耗散系统中的混沌及其控制与同步研究中遇到的有关基本概念和问题作一些哲理性解释。内容涉及混沌的基本假设及其标志性特征、通向混沌的道路、混沌系统的相空间基本格局、混沌控制的基本策略、所谓‘混沌同步’以及‘噪声诱导同步’的实质含意、随机混沌的约定性定义、以及数值仿真在混沌研究中的作用等。对混沌及其控制与同步、以及随机混沌提出了一些独特的新见解。     

Dynamical behaviour of a friction oscillator with simultaneous self and external excitation

Friction-induced self-sustained oscillations, also known as stick-slip vibrations, occur in mechanical systems as well as in everyday life. In engineering applications these vibrations are undesirable and should be avoided. In the present paper it is shown how the very robust limit cycles of stick-slip vibrations can be broken up by a harmonic disturbance. Based on a simple model of a friction oscillator with simultaneous self and external excitation the resulting bifurcation behaviour and the routes to chaos are investigated for a wide range of system parameters. The influence of different types of friction characteristics is elaborated and the admissibility of smoothing procedures is examined by comparing results gained for non-smooth and smoothed friction characteristics.     

Real-time synchronization of batch trajectories for on-line multivariate statistical process control using Dynamic Time Warping

This paper addresses the real-time monitoring of batch processes with multiple different local time trajectories of variables measured during the process run. For Unfold Principal Component Analysis (U-PCA)—or Unfold Partial Least Squares (U-PLS)-based on-line monitoring of batch processes, batch runs need to be synchronized, not only to have the same time length, but also such that key events happen at the same time. An adaptation from Kassidas et al.'s approach [1] will be introduced to achieve the on-line synchronization of batch trajectories using the Dynamic Time Warping (DTW) algorithm. In the proposed adaptation, a new boundaries definition is presented for accurate on-line synchronization of an ongoing batch, together with a way to adapt mapping boundaries to batch length. A relaxed greedy strategy is introduced to avoid assessing the optimal path each time a new sample is available. The key advantages of the proposed strategy are its computational speed and accuracy for the batch process context. Data from realistic simulations of a fermentation process of the Saccharomyces cerevisae cultivation are used to illustrate the performance of the proposed strategy.     

一类离心调速器的Hopf分岔及其混沌控制

研究了受外部扰动的离心调速器系统的复杂动力学行为。通过系统运动的拉格朗日方程和牛顿第二定律,建立了离心调速器系统的动力学方程,应用Lyapunov直接方法分析了该系统平衡点的稳定性。利用相图分析了系统超混沌吸引子的特性,通过Poincaré截面和Lyapunov指数研究了系统的超混沌行为,通过仿真系统的分岔图和相图分析了系统通向混沌的道路,并且验证了该系统的分岔图与Lyapunov指数谱是完全吻合的。通过对系统施加非线性反馈控制器,并选取合适的反馈系数,可以获得各种不同的所需的稳定周期轨道。对受外部扰动的离心调速器系统施于此控制,计算机数值模拟结果表明,这种控制方法简便有效,控制范围广。     

碰撞阻尼器系统的分岔、混沌与控制

对碰撞阻尼器振动系统推导了周期解存在的条件，并利用Poincare映射和数字仿真进行了分岔与混沌运动的研究。计算结果表明，这种非线性碰撞振动系统在特定的参数条件下，除了稳定的周期运动形态外，还会沿着倍周期分岔、HOPF分岔及拟周期环面破裂等分岔进入混沌运动。因此，为了有效地利用碰撞阻尼器特性控制振动，在设计和使用碰撞阻尼器时应考虑参数满足周期运动的条件，避免由于自身的非线性特性而产生的混沌运动。     

机电设备早期故障微弱信号的非线性检测方法及工程应用

阐述了并联随机共振、混沌振子、差分振子的基本原理和数学模型.并联随机共振利用相关分析从多个随机共振输出结果中提取出相同成分,在一定程度上减小了对参数设置的依赖性.当混沌振子从混沌状态向大尺度周期状态转变时,其相图的Hu氏不变矩值将发生明显的跃变,利用Hu氏不变矩的跃变对混沌振子的状态进行自动定量识别.差分振子相图的大小与待检测信号幅值之间呈现出一种线性比例关系,弥补了差分振子不能检测信号幅值的缺陷.将这三种非线性方法应用于机电设备故障诊断中,成功地提取出了设备早期故障的微弱特征信息,取得了理想的效果.     

基于分形和子波变换自适应控制混沌

在自适应控制混沌方法的基础上结合子波分析、分形理论，提出了一种自适应控制受迫Ｄｕｆｉｎｇ振子的混沌运动的方法。克服了需要预先知道系统的具体动力学模型及需要设计一个参考模型等缺陷。从实验中即可测得系统的某个输出量，引入外力控制混沌运动。数值分析表明在适当的控制信号下，混沌运动得到了很好的控制。     

Integrability and non-integrability of periodic non-autonomous Lyness recurrences

This paper studies non-autonomous Lyness-type recurrences of the form x _n+2 = (a _n + x _n+1)/x _n , where {a _n } is a k-periodic sequence of positive numbers with primitive period k. We show that for the cases k ∈ {1, 2, 3, 6}, the behaviour of the sequence {x _n } is simple (integrable), while for the remaining cases satisfying this behaviour can be much more complicated (chaotic). We also show that the cases where k is a multiple of 5 present some different features.     

具有时滞反馈控制的非线性主动悬架系统的稳定性、分岔和混沌

研究了具有时滞反馈控制的非线性主动悬架系统模型,该模型考虑了悬架弹簧和阻尼的非线性特性.运用广义Sturm准则推导了时滞无关稳定区域的临界增益和稳定性开关的临界时滞.在不同稳定性区间内选取参数组合进行数值模拟,验证理论分析的有效性.在动力学方程的基础上,利用分岔图、庞加莱映射图和时域图,研究了在路面激励下的悬架系统的非...     

Influence of ZnO nanoparticles on Coumarin-503 and Coumarin-540 dye mixture for energy transfer distributed feedback dye lasers

Abstract

Using organic dyes Coumarin-503 (C503) and Coumarin-540 (C540) as donor and acceptor dyes, respectively, and Nd-YAG as pumping source (355 nm), an energy transfer-distributed feedback dye laser (ETDFDL) was constructed and its characteristics studied. Theoretical studies such as critical transfer radius (R_o), critical concentration (C_o), and half quenching concentration (C_1/2) were carried out using the absorption and fluorescence spectra of donor and acceptor dyes. On varying the input pump energy to the nanoparticle-incorporated ETDFDL and keeping the acceptor and donor dye concentrations constant, the lasing output obtained was found to be higher than that without the use of nanoparticles. This enhancement was due to the size, shape, and coupling between nanoparticles with the dye mixture. Tunability in the range of 435–553 nm was obtained for both donor (C503) and acceptor (C540) DFDL as a function of the angle of interfering beams of the pump laser.     

关于动力学系统伪谱与扰动系统谱之间关系的研究

研究了非正规系统在扰动的情况下波形松弛算子的谱与未扰动系统的伪谱之间的关系,我们的研究清楚地表明伪谱总比扰动后的谱包含更多的信息．从而进一步证实了在非正规系统中伪谱确实是一个有用的科学计算工具。     

Vapor growth of CdSe:Cr and CdS:Cr single crystals for mid-infrared lasers

Single crystals of CdSe:Cr and CdS:Cr with the doping level up to 10¹⁹ cm⁻³ were grown by a vapor phase contact-free technique. An efficient room-temperature pulsed and continuous wave (CW) lasing with the CdSe:Cr crystal was achieved. First a pulsed lasing with the CdS:Cr crystal was also demonstrated. The slope efficiency on the absorbed energy was as high as 46.5% for Cr²⁺:CdSe and 39% for Cr²⁺:CdS lasers. Using an intra-cavity prism, the Cr²⁺:CdSe laser wavelength was continuously tuned from 2.26 to 3.61 μm while the Cr²⁺:CdS laser from 2.2 to 3.3 μm. For the laser wavelength, the crystal passive loss coefficient was estimated to be smaller than 0.045 cm⁻¹ for CdSe:Cr crystals and 0.039 cm⁻¹ for CdS:Cr crystals. For the Cr²⁺:CdSe laser, the CW output power up to 1.07 W was achieved.     

压电智能结构有限元动力模型及其振动主动控制的研究

推导了压电智能结构的有限元动力方程;应用模态控制理论对结构振动主动控制的原理和策略进行了讨论,利用两种反馈控制律研究了智能结构振动抑制的问题,最后应用本文方法对一新型2—DOF平面并联压电智能杆机构进行了振动主动控制实验研究,结果表明系统的稳定时间从抑振前的488ms缩短到了抑振后的115ms,验证了本文方法的有效性。     

一类高阶广义抛物型方程组的周期边值问题与初值问题

本文用Galerkin方法研究了一类高阶广义抛物型方程组的周期边值问题与初值问题的整体广义解与整体古典解的存在唯一性以及光滑性。     

Workload prediction for improved design and reliability of complex systems

This paper describes a method and a tool for analysing and predicting workload for the design and reliability of complex socio-technical systems. It concentrates on the need to assess workload early in the design phase to prevent systems failures. This is a continuation of our previous work on workload assessment. The method is supported by a tool that enables scenario-based validation of prospective socio-technical systems designs such as command and control rooms of military vessels. The approach combines probabilistic measures of human performance with subjective estimates of workload. The causal relationships of performance shaping factors (PSF) are modelled in a Bayesian belief network (BBN) and used to assess the agent's operational performance and reliability. Workload for each agent is calculated based on demand placed upon agents in terms of behavioural response to tasks, communications and interactions between humans and technology. The approach uses scenarios to stress test prospective system designs, where each scenario is modelled as a sequence of events. Reliability is expressed in terms of human error and is dynamically assessed throughout test scenario executions using BBN technology. The innovation beyond traditional reliability analysis relies to the use of dynamic and static estimates of reliability inputs for better informed assessment. This method enables identification of performance bottlenecks to be addressed by the designer early in the design phase. A case study is presented that demonstrates the use of the method and tool for the design of the command and control room of a military vessel.     

Laser methods and facilities for monitoring the geometric dimensions of components

Comparative characteristics are provided for laser methods of measuring geometric dimensions of components. The main problems are considered that arise with measurement by the triangulation method. An instrument is described that makes it possible to measure the parameters of railway wagon spring suspenders. __________ Translated from Izmeritel’naya Tekhnika, No. 2. pp. 32–35, February, 2008.     

An extension of the Kazakov relationship for non-Gaussian random variables and its use in the non-linear stochastic dynamics

A generalization for non-Gaussian random variables of the well-known Kazakov relationship is reported in this work. If applied to the stochastic linearization of non-linear systems under non-Gaussian excitations, this relationship allows us to define the significance of the linearized stiffness coefficient. It is the sum of that one known in the literature (the mean of the tangent stiffness) and of terms taking into account the non-Gaussianity of the response. Moreover, the relationship here given is used for finding alternative formulae between the moments and the quasi-moments. Lastly, it is used in the framework of the moment equation approach, coupled with a quasi-moment neglect closure, for solving non-linear systems under Gaussian or non-Gaussian forces. In this way an iterative procedure based on the solution of a linear differential equation system, in which the values of the response mean and variance are those of the precedent iteration, is originated. It reveals a good level of accuracy and a fast convergence.     

Development of a method and apparatus for measuring the light-reflecting characteristics of infrared optoelectronic systems

Questions related to the study of the light-reflecting characteristics of optoelectronic systems that function in the infrared domain are considered. A method and combined structural and functional optical apparatus scheme is proposed that makes it possible to perform measurements of the light-reflecting characteristics of modern infrared devices; a mathematical apparatus for processing the measurement results is also proposed. The expected value of the error of such measurements is determined. __________ Translated from Izmeritel’naya Tekhnika, No. 9, pp. 24–28, September, 2007.