Dynamics of a Nonautonomous Plant Disease Model with General Nonlinear Incidence Rate and Time-Varying Impulse

In this paper, for controlling the spread of plant diseases, a nonautonomous SEIS (Susceptible → Exposed → Infectious → Susceptible) epidemic model with a general nonlinear incidence rate and time-varying impulsive control strategy is proposed and investigated. This novel model could result in an objective criterion on how to control plant disease transmission by replanting of healthy plants and removal of infected plants. Using the method of small amplitude perturbation, the sufficient conditions under which guarantee the globally attractive of the disease-free periodic solution and the permanence of the disease are obtained, that is, the disease dies out if R12>1.

基于System Generator的宽带电力线脉冲噪声实现方法

随机脉冲噪声是影响用电信息采集系统中宽带电力线载波(BPLC)通信的关键因素。目前的评估测试技术中缺乏标准化的宽带电力线噪声建模和实现方法。研究了经典的Middleton Class-A脉冲噪声模型,分析了二项分布逼近泊松分布的条件,从伯努利实验模型出发,依据Middleton Class-A模型的脉冲指数设定满周期线性同余法生成伪随机序列的阈值,通过判定阈值以获取特定强度的泊松序列。该序列在加权因子部分进行数值运算,得到特定状态的噪声方差,利用乘法器与高斯白噪声序列相乘。所提Class-A脉冲噪声的System Generator模块化设计方法能够实现快速的算法验证,通过对比现场可编程门阵列(FPGA)输出与理论随机脉冲噪声的统计特性,证明了该实现方法的有效性与准确性。

Impulsive generalized synchronization of chaotic system

In this paper, with a given manifold y = H（x）, we have constructed a response system for a continuous-time chaotic system as a drive system, and used impulsive control theory to demonstrate theoretically that this response system can achieve impulsive generalized synchronization （GS） with the drive system. Our theoretical result is supported by numerical examples.

Influence of an irradiation of a liquid phase by nanosecond electromagnetic impulses (NEMI) on properties of metals and alloys

The results of research on influence of an irradiation of a liquid phase by nanosecond electromagnetic impulses(NEMI) on processes of crystallization and structurization,physicomechanical and operational properties of copper,aluminium and alloys on their basis(bronze and silumin) were presented.

Proper Understanding of the Nerve Impulses and the Action Potential

Neurologists define the transmission of nerve impulses across the membranes of the neural cells as a result of difference in the concentration of ions while they measured an electric potential, called as an action potential, which allows the propagation of such nerve impulses as electrical signals. Such measurements should guide them to a logical explanation of the nerve impulses as electric charges driven by the measured action potential. However, such logical conclusion, or explanation, is ignored due to a wrong definition of the flow of electric charges as a flow of electrons that cannot pass through neural networks. According to recent studies, electric charges are properly defined as electromagnetic (EM) waves whose energy is expressed as the product of its propagating electric potential times their entropy flow which is adhered to the flow of such energy. Such definition matches the logical conclusion of the nerve impulses as electric charges, as previously explained, and defines the entropy of the neural network, measured by Ammeters, in Watt or Joule/Volt. The measured entropy represents a neurodiagnostic property of the neural networks that measures its capacity to allow the flow of energy per unit action potential. Theoretical verification of the innovative definition of nerve impulses is presented by following an advanced entropy approach. A proper review of the machine records of the stimulating electric charges, used in the diagnosis of the neural networks, and the stimulated nerve impulses or stimulated responses, represents practical verifications of the innovative definitions of the electric charges and the nerve impulses. Comparing the functioning of the thermoelectric generators and the brain neurons, such neurons are defined as thermoelectric generators of the electric nerve impulses and their propagating, or action, potential.

Distributional Relations on Impulse Radiating Surface and Point Type Sources

The electromagnetic field relations are demonstrated on impulse radiating surface and point type sources, which are characterized by first and second order singularities at rest in a Schwartz-Sobolev space setting. The investigation starts with a general introduction to Schwartz-Sobolev distributions, the electromagnetic field equations and various modes of impulsive radiation. This is followed by an outline of temporal distributional relations in arbitrary media and distributional derivative operations on an arbitrary regular surface, all of which are employed in an investigation of impulse radiation mechanism on single and double layer sources. Similar steps are followed in a description of point distributions and investigation of impulse radiation mechanism on electric and magnetic point dipoles.

Indirect Adaptive Fuzzy and Impulsive Control of Nonlinear Systems

The problem of indirect adaptive fuzzy and impulsive control for a class of nonlinear systems is investigated. Based on the approximation capability of fuzzy systems, a novel adaptive fuzzy and impulsive control strategy with supervisory controller is developed. With the help of a supervisory controller, global stability of the resulting closed-loop system is established in the sense that all signals involved are uniformly bounded. Furthermore, the adaptive compensation term of the upper bound function of the sum of residual and approximation error is adopted to reduce the effects of modeling error. By the generalized Barbalat＇s lemma, the tracking error between the output of the system and the reference signal is proved to be convergent to zero Asymptotically. Simulation results illustrate the effectiveness of the proposed approach.

Mild Solutions for Nonlocal Impulsive Fractional Semilinear Differential Inclusions with Delay in Banach Spaces

In this paper, we give various existence results concerning the existence of mild solutions for nonlocal impulsive differential inclusions with delay and of fractional order in Caputo sense in Banach space. We consider the case when the values of the orient field are convex as well as nonconvex. Our obtained results improve and generalize many results proved in recent papers.

Analysis of Nonlinear Stochastic Systems with Jumps Generated by Erlang Flow of Events

In this paper we consider the stochastic systems with jumps (random impulses) generated by Erlang flow of events that lead to discontinuities in paths. These systems may be used in various applications such as a control of complex technical systems, financial mathematics, mathematical biology and medicine. We propose to use a spectral method formalism to the probabilistic analysis problem for the stochastic systems with jumps. This method allows to get a solution of the analysis problem in an explicit form.

Impulsive synchronization of two coupled complex networks with time-delayed dynamical nodes

In this paper, we investigate the impulsive synchronization between two coupled complex networks with time- delayed dynamical nodes. Based on the Lyapunov stability, the linear feedback control and the impulsive control theories, the linear feedback and the impulsive controllers are designed separately. By using the generalized Barbalat＇s lemma, the global asymptotic impulsive synchronization of the drive-response complex networks is derived and some corresponding sufficient conditions are also obtained. Numerical examples are presented to verify the effectiveness and the correctness of the synchronization criteria.

On Wavelet Transform General Modulus Maxima Metric for Singularity Classification in Mammograms

Continuous wavelet transform is employed to detect singularities in 2-D signals by tracking modulus maxima along maxima lines and particularly applied to microcalcification detection in mammograms. The microcalcifications are modeled as smoothed positive impulse functions. Other target property detection can be performed by adjusting its mathematical model. In this application, the general modulus maximum and its scale of each singular point are detected and statistically analyzed locally in its neighborhood. The diagnosed microcalcification cluster results are compared with health tissue results, showing that general modulus maxima can serve as a suspicious spot detection tool with the detection performance no significantly sensitive to the breast tissue background properties. Performed fractal analysis of selected singularities supports the statistical findings. It is important to select the suitable computation parameters-thresholds of magnitude, argument and frequency range-in accordance to mathematical description of the target property as well as spatial and numerical resolution of the analyzed signal. The tests are performed on a set of images with empirically selected parameters for 200 μm/pixel spatial and 8 bits/pixel numerical resolution, appropriate for detection of the suspicious spots in a mammogram. The results show that the magnitude of a singularity general maximum can play a significant role in the detection of microcalcification, while zooming into a cluster in image finer spatial resolution both magnitude of general maximum and the spatial distribution of the selected set of singularities may lead to the breast abnormality characterization.

RS堆积体滑坡涌浪特征数值模拟研究

库区滑坡涌浪是滑坡产生的次生灾害,严重威胁库区工程安全及大坝稳定运行.澜沧江RM水电站RS堆积体方量巨大,且位于近坝区,开展RMRS堆积体滑坡涌浪特征研究对大坝工程安全设计和施工至关重要.本文建立RS堆积体滑坡涌浪远近场计算模型,基于光滑粒子流体动力学方法及浅水方程,研究RM工程正常蓄水位2895m情况下RS堆积体滑动产生的涌浪特征,并与经验公式法进行对比.研究表明:分析所采用的数值模拟方法在研究滑坡涌浪中具有优势,该方法可准确模拟滑坡体入水产生的非线性流固耦合过程,准确捕捉涌浪传播过程中受到复杂地形影响以及爬升过程中的地形相关性.研究结果可为评估RMRS堆积体滑坡涌浪对工程安全的影响提供参考.

国际原油价格对中国通货膨胀的非线性冲击

为更好了解国际油价冲击下的通胀风险,分别以国际原油价格、PPI和CPI为门槛变量,使用门槛向量自回归模型与广义脉冲响应函数分析了国际原油价格波动对中国PPI和CPI的冲击。研究发现:国际原油价格波动对中国的PPI和CPI有显著影响,且影响程度和方向取决于国际原油价格、PPI和CPI所处的门槛区间。当国际原油价格处于不同水平时,国际油价冲击造成的影响各有不同。当通货膨胀处于较高水平时,国际油价冲击对通货膨胀造成的影响较大,反之,则影响较小。此外,国际原油价格冲击对通货膨胀的影响具有非对称性,但国际油价上涨造成的影响并没有总是大于下跌冲击。

中国耕地集约利用度驱动因素研究

基于1978—2020年数据,利用GA-BP神经网络模型对耕地集约度利用进行定量评价,在协整分析的基础上,结合向量误差修正模型、广义脉冲响应函数和方差分解,揭示了耕地集约利用度与各驱动因素之间的长期均衡关系和短期作用机制.结果表明:(1)耕地集约利用度和自然灾害、农民收入、农业科技进步、财政支农、劳动力转移存在长期均衡关系.(2)农业科技进步对耕地集约利用度有显著正向影响,而农业灾害面积短期会对耕地集约利用度会产生负向影响.(3)劳动力转移和农民收入对耕地集约利用度的影响呈现先抑后扬的特点,而财政支农则呈现出先扬后抑的特点.基于模型分析,提出了提高耕地集约利用度及保障国家粮食安全的对策建议.

基于sigmoid-sinh分段函数的改进FxGMCC算法

为了解决滤波-x广义最大熵准则(FxGMCC)算法在处理噪声主动控制时存在快速收敛和低稳态误差之间的矛盾,分别采用sigmoid函数和sinh函数,提出了基于sigmoid函数的变步长FxGMCC(SFxGMCC)算法和基于sinh函数的变步长FxGMCC(ShFxGMCC)算法。然后,通过分析SFxGMCC算法和ShFxGMCC算法变步长性能,提出了一种基于sigmoid-sinh分段函数的SSFxGMCC算法。为了验证SSFxGMCC算法性能,分别采用alpha稳定分布噪声和混合噪声作为输入信号,对SSFxGMCC算法与FxGMCC算法、SFxGMCC算法与ShFxGMCC算法进行性能仿真实验。结果表明,与FxGMCC算法相比,采用SSFxGMCC算法在应对alpha稳定分布噪声和混合噪声时,在收敛速度得到提升的前提下,平均降噪量分别提升了16.5%和17.4%。由此可知,SSFxGMCC算法有效解决了FxGMCC算法在应对噪声主动控制时快速收敛和低稳态误差无法同时满足的问题。

“神经冲动的产生和传导”境脉式主题教学设计

围绕特定主题,探索从情境走向境脉的主题式教学路径,以“神经冲动的产生和传导”为例,以境脉为“藤蔓”,引导学生启境而入、拾境而上、悟境而出,开展“一境贯穿”的主题式教学,促进学生深度学习,发展高阶思维,落实学科核心素养。

基于冲击发电机系统的中压断路器背对背电容器组开合试验技术

背对背电容器组开合试验用于考核断路器开合电容器组的重击穿概率,是重要的型式试验项目。针对关合涌流峰值I_(bi)和涌流频率f_(bi)在试验过程中难以准确调控,文中在分析国家标准对试验回路要求的基础上,提出以冲击发电机为试验电源的背对背电容器组三相开合试验回路,应用等效电路推导了涌流峰值I_(bi)和涌流频率f_(bi)的一般计算公式,并得出在试验电压12 kV,关合涌流峰值20 kA,开断电流分别为400 A和800 A时,线路长度l和电容值CS、涌流频率f_(bi)之间的量化关系,结果表明线路长度l与电容值C_(S)呈正相关,与涌流频率f_(bi)呈负相关。最后,应用3200 MVA冲击发电机试验系统,配置电源回路和负载回路的三相电容器组,进行了额定电压12 kV断路器背对背电容器组开合试验,关合涌流峰值I_(bi)和涌流频率f_(bi)均满足标准要求,验证了文中计算方法和试验回路的正确性和有效性。

高压油顶装置在冲击发电机组中的研究及应用

分析了冲击发电机组轴承采用高压油顶装置的必要性,研究了高压油顶装置的原理及其调试方法,介绍了高压油顶装置在工程现场的应用情况。指出高压油顶装置可在发电机组轴承座轴瓦中注入高压油,顶起转子,避免转子和轴瓦相互干摩擦,有效地延长了冲击发电机组使用寿命,并提高了安全运行水平。

7200kV/480kJ冲击电压发生器的输出电压特性

介绍了国家电网公司特高压直流试验基地户外冲击试验场的7200kV/480kJ冲击电压发生器的结构特点,并对该冲击电压发生器的雷电冲击电压、标准操作冲击电压、500μs和1000μs长波头操作冲击电压的输出特性进行了试验研究。试验结果表明:雷电冲击输出电压幅值达到了6271kV,标准操作冲击电压的棒板间隙耐受电压和击穿电压分别达到了3844和4845kV。表明该冲击电压发生器可以满足±800kV特高压直流输电技术和更高电压等级输电技术的试验要求。

接地装置冲击大电流试验系统研制及杆塔接地冲击特性测试

为模拟真实雷电冲击电流在接地装置及其周围土壤中的散流过程,准确掌握接地装置的冲击特性,研制了接地装置的冲击大电流试验系统。在大量仿真计算和系统方案论证的基础上,提出了围绕直径40m圆环形回流电极均匀对称布置的4台分体式冲击大电流发生器的技术方案,其中单台冲击电流发生器的充电电压可达1 000kV,该系统可在负载大于4Ω的情况下产生峰值为100kA、波形为8μs/20μs的标准雷电冲击电流。测量得到的地表、回流电极地电位升分布均匀,证实了试验冲击电流地中分布与真实雷电流地中分布的等效性。针对该系统提出了工频、冲击接地电阻的修正公式。通过试验得到了典型杆塔接地装置在8μs/20μs、2.6μs/50μs冲击电流作用下的冲击特性曲线。该曲线表明在低电阻率土壤中该装置的冲击接地电阻随冲击电流峰值的变化并不显著。