含断续节理脆性岩体灌浆效果研究

本文针对含断续节理天然岩体灌浆前后不同节理接触度,运用断裂力学理论建立相应的岩体抗剪强度分析模型。并用有限单元法研究了节理面不同接触度条件下岩体沿节理面方向综合抗剪强度参数的变化,从而定量地给出了灌浆效果与岩体强度的相互关系。     

滚子齿式空间分度凸轮机构的研究

本文以微分几何和空间旋转矩阵算子理论为数学工具,应用空间曲面啮合原理,对滚子齿式空间分度凸轮机构进行了系统的研究。推导了凸轮轮廓曲面方程、啮合方程和压力角计算公式,并对凸轮曲面的曲率进行了分析,给出了主曲率、诱导主曲率等一系列计算公式,最后给出了凸轮工作曲面产生根切的判别条件。     

双链轮间歇运动机构分析

本文讨论了双链轮间歇运动机构的工作原理、运动分析、运动参数和特性.     

基于嵌入式Linux技术的间歇式染色机控制器的研究

针对传统间歇式控制器在联网、人机交互、染程编辑、控制运算等功能上的不足,提出基于嵌入式Linux技术的间歇式染机控制器方案,并采用开发源代码免费嵌入式Linux系统eCos,在PC/104硬件平台上进行了实现.     

地温可恢复性对土壤源热泵运行的影响

在地源热泵运行过程中,利用间歇过程,弥补土壤传热慢的缺陷。土壤源热泵间歇运行时间可以改变土壤温度的变化规律,增强传热并实现更佳的热泵运行工况。实验是在冬季运行工况下进行的,着重对间歇运行条件下地温变化趋势进行研究。     

循环间歇溅射工艺对PLT薄膜性能的影响

采用射频磁控溅射技术利用循环间歇溅射工艺,在Pt/Ti/SiO2/Si基片上制备出了镧钛酸铅(PLT)薄膜。通过原子力显微镜、X-射线衍射仪分析了循环间歇溅射工艺对薄膜形貌、结构和铁电性能的影响。实验结果表明,相比于连续溅射工艺,循环间歇溅射工艺的基片温度较低,且制得的PLT薄膜晶粒细小、均匀,结构致密。薄膜具有纯钙钛矿型结构,循环次数从1次增加到3次,其(100)和(200)峰衍射强度逐渐增强,结晶性提高,铁电性能逐渐增强,其饱和极化强度由28μC/cm2增大到53μC/cm2,剩余极化强度由5μC/cm2增大到12μC/cm2。循环4次溅射后,薄膜的结晶性和铁电性开始下降。     

Diagnosis of Intermittent Faults

The diagnosis of intermittent faults in dynamic systems modeled as discrete event systems is considered. In many systems, faulty behavior often occurs intermittently, with fault events followed by corresponding reset events for these faults, followed by new occurrences of fault events, and so forth. Since these events are usually unobservable, it is necessary to develop diagnostic methodologies for intermittent faults. Prior methodologies for detection and isolation of permanent faults are no longer adequate in the context of intermittent faults, since they do not account explicitly for the dynamic behavior of these faults. This paper addresses this issue by: (i) proposing a modeling methodology for discrete event systems with intermittent faults; (ii) introducing new notions of diagnosability associated with fault and reset events; and (iii) developing necessary and sufficient conditions, in terms of the system model and the set of observable events, for these notions of diagnosability. The definitions of diagnosability are complementary and capture desired objectives regarding the detection and identification of faults, resets, and the current system status (namely, is the fault present or absent). The associated necessary and sufficient conditions are based upon the technique of diagnosers introduced in earlier work, albeit the structure of the diagnosers needs to be enhanced to capture the dynamic nature of faults in the system model. The diagnosability conditions are verifiable in polynomial time in the number of states of the diagnosers.     

Lag synchronisation of master–slave dynamical systems via intermittent control

In this paper, the problem on lag synchronisation is investigated for a master–slave model. The intermittent control method is used to design controllers, lag synchronisation criteria are proposed. Together with some Lyapunov–Krasovskii functionals and effective mathematical techniques, several conditions are derived. An example is given to illustrate the effectiveness of the proposed methods.     

Constrained intermittent model predictive control

The generalised hold formulation of intermittent control is re-examined and shown to have some useful theoretical and practical properties. It is shown that this provides a foundation for constrained model predictive control in an intermittent context. The method is illustrated using an example and verified with experimental results.     

Power-constrained intermittent control

In this article, input power, as opposed to the usual input amplitude, constraints are introduced in the context of intermittent control. They are shown to result in a combination of quadratic optimisation and quadratic constraints. The main motivation for considering input power constraints is its similarity with semi-active control. Such methods are commonly used to provide damping in mechanical systems and structures. It is shown that semi-active control can be re-expressed and generalised as control with power constraints and can thus be implemented as power-constrained intermittent control. The method is illustrated using simulations of resonant mechanical systems and the constrained nature of the power flow is represented using power-phase-plane plots. We believe the approach we present will be useful for the control design of both semi-active and low-power vibration suppression systems.