冠心病人心电图信号的非线性动力学特性

采用非线性动力学方法对冠心病人的同步十二导联常规心电信号（Electrocardiogram:ECG)进行了研究,计算了每一导联心电图信号的关联维数D2,并与正常对照组进行对比,发现不论冠心病人（CHD）还是健康人,心电图信号均表现出强烈的混沌动力学特征,从不同导联得出的D2值不同,同一导联相比较,除Ⅰ,Ⅱ,Ⅲ导联外,冠心病人的D2显著低于正常人的D2值,显示在心肌缺血的情况下,心脏ECG吸引子的复杂程度降低了。结果表明,D2可以区别正常人与冠心病人,也可以为确定病变部位提供有价值的诊断信息。     

A stochastic production planning problem in hybrid manufacturing and remanufacturing systems with resource capacity planning

DIRECT is derivative-free global-search algorithm has been found to perform robustly across a wide variety of low-dimensional test problems. The reason DIRECT’s robustness is its lack of algorithmic parameters that need be “tuned” to make the algorithm perform well. In particular, there is no parameter that determines the relative emphasis on global versus local search. Unfortunately, the same algorithmic features that enable DIRECT to perform so robustly have a negative side effect. In particular, DIRECT is usually quick to get close to the global minimum, but very slow to refine the solution to high accuracy. This is what we call DIRECT’s “eventually inefficient behavior.” In this paper, we outline two root causes for this undesirable behavior and propose modifications to eliminate it. The paper builds upon our previously published “MrDIRECT” algorithm, which we can now show only addressed the first root cause of the “eventually inefficient behavior.” The key contribution of the current paper is a further enhancement that allows MrDIRECT to address the second root cause as well. To demonstrate the effectiveness of the enhanced MrDIRECT, we have identified a set of test functions that highlight different situations in which DIRECT has convergence issues. Extensive numerical work with this test suite demonstrates that the enhanced version of MrDIRECT does indeed improve the convergence rate of DIRECT.     

Adsorption of graphene for the removal of inorganic pollutants in water purification: a review

Graphene has aroused widespread attention as a new type of adsorbents due to its outstanding ability for the removal of various pollutants from aqueous solutions. This review summarizes the application of graphene-based nanomaterials as an advanced adsorbent for the removal of inorganic pollutants including anionic and cationic type. The adsorption properties, mechanisms, isotherms, kinetics, thermodynamics and regeneration of adsorbents are all summarized, and the further research trends on graphene-based nanomaterials in the removal of pollutants are also given.     

基于流水线调度问题的模型与局部搜索算法

在基于流水线的调度问题中,所有工件按照相同的顺序访问机器,但部分或全部工件可以不必在某些机器上进行加工.标准flowshop问题是这种流水线调度问题的一个特例.研究了带序依赖和机器依赖加工准备时间的流水线调度问题,针对该问题建立了一个基于序列的0～1混合整数规划模型,目标函数是总加权完工时间最小,提出了相应的局部搜索算法,实验结果证明了算法的有效性和可应用性,所提出的局部搜索算法的求解思路对同类流水线调度问题具有指导意义。     

无衍射光莫尔条纹空间直线度误差的测量方法

将无衍射光与莫尔条纹技术相结合,发展了一种新的连续空间直线度误差测量技术.此方法利用了无衍射光和环状莫尔条纹的图像自定位基准特性.由于无衍射光的大光学口径和光学数值孔径,此方法适用于长、短距离连续空间直线度误差测量,并且测量系统具有体积小、操作简单、分辨率高等优点.     

基于微控制器产生随机数的新方法

为产生应用于实践中的真正随机数, 提出了一种利用微控制器的定时器产生随机数的新方法。 使用微控制器的定时器检测按键按下的时间, 利用按下按键的时间间隔的随机性获得随机数。 微控制器的定时器工作在定时状态, 由微控制器监测按键, 按下按键时, 微控制器立即读取其定时器的值, 此数值即为随机数。 通过统计学方法对实验数据的概率密度和自相关性进行了分析和验证。 实验结果显示, 其概率密度分布均匀且其自相关性接近零。 采用该方法可产生随机数序列, 且相比于纯数学的产生随机序列的方法更为简单、 方便。     

腔内倍频Nd：YAG激光器中的偏振匹配与1／4λ波片的作用

讨论了腔内倍频Ｎｄ：ＹＡＧ激光器中的偏振匹配原理以及由于倍频晶体双折射效应所引起的偏振损耗，分析了解决这一矛盾的一种有效方法——腔内插入１．０６μｍ激光的１／４λ波片的基本原理。     

Effect of primary phase structure on the undercoolability of quasicrystal-forming melt

The relationship between α and Δ T rel is investigated, where α is a factor that depends on the structure of primary phase and Δ T rel , the relative undercooling of melt. A linear relationship between α and the relative undercooling Δ T rel is observed, which is represented by Δ T rel ＝ A+Bα.     

心脏电信号的动态关联维分析

通过一组动物实验，采用混沌分析方法，对心脏缺血型的ECG电信号进行分析，给出了实验方法、理论、算法，并在分析数据的基础上，肯定了关联维数在分析心脏电活动中的价值，以及关联维对心肌缺血病情的动态变化。     

Lyapunov exponents for synchronous 12-lead ECG signals

The Lyapunov exponents of synchronous 12-lead ECG signals have been investigated for the first time using a multi-sensor (electrode) technique. The results show that the Lyapunov exponents computed from different locations on the body surface are not the same, but have a distribution characteristic for the ECG signals recorded from coronary artery disease (CAD) patients with sinus rhythms and for signals from healthy older people. The maximum Lyapunov exponent L1 of all signals is positive. While all the others are negative, so the ECG signal has chaotic characteristics. With the same leads, L1 of CAD patients is less than that of healthy people, so the CAD patients and healthy people can be classified by L1, L1 therefore has potential values in the diagnosis of heart disease.