不确定非线性动力系统的稳定性分析

本文讨论渐近稳定的非线性名义动力系统在非线性时变扰动下的鲁棒稳定性问题。应用Ｌｙａｐｕｎｏｖ稳定性定理及其推广定理得出了非线性动力系统鲁棒稳定的若干判别准则，并给邮了应用所得准则的实际算例。     

矩形多环芳烃的合成

本文用3,4-二苯基-2,5-二(3,5-二溴苯基)环戊二烯酮(4a)与二苯乙炔(5a)通过Diels-Alder环加成反应得到1,2,4,5-四苯基-3,6-二(3,5-二溴苯基)苯(6a)。化合物6a通过经典的Suzuki偶联反应得到1,2,4,5-四苯基-3,6-二(3,5-二(4-十二烷基噻吩))苯基苯(8a),再利用Fe Cl3作为氧化剂发生Scholl氧化脱氢关环反应,得到目标化合物1a。采用类似合成方法,得到目标化合物1b。化合物的结构均通过1H NMR和MALDI-TOF MS表征,并对其光谱特征、热性能及电学性能进行了初步研究。     

Dry-friction-induced self-excitation of a rectangular liquid-filled tank

Nonlinear Dynamics - The self-excitation of spring–mass system subjected to dry friction has been studied for decades because of its interesting and complex nonlinear dynamics behaviors. In...     

Response analysis of a dual-disc rotor system with multi-unbalances–multi-fixed-point rubbing faults

Rotor unbalance and rub-impact are major concerns in rotating machinery. In order to study the dynamic characteristics of these machinery faults, a dual-disc rotor system capable of describing the mechanical vibration resulting from multi-unbalances and multi-fixed-point rub-impact faults is formulated using Euler beam element. The Lankarani–Nikravesh model is used to describe the nonlinear impact forces between discs and casing convex points, and the Coulomb model is applied to simulate the frictional characteristics. To predict the moment of rub-impact happening, a linear interpolation method is carried out in the numerical simulation. The coupling equations are numerically solved using a combination of the linear interpolation method and the Runge–Kutta method. Then, the dynamic behaviours of the rotor system are analysed by the bifurcation diagram, whirl orbit, Poincaré map and spectrum plot. The effects of rotating speed, phase difference of unbalances, convex point of casing and initial clearance on the responses are investigated in detail. The numerical results reveal that a variety of motion types are found, such as periodic, multi-periodic and quasi-periodic motions. Moreover, the energy transfer between the compressor disc and the turbine disc occurs in the multi-fixed-point rubbing faults. Compared with the parameters of the turbine disc, those of the compressor disc can affect the motion of the rotor system more significantly. That is, the responses exhibit simple 1T-periodic motion in the wide range of rotating speed under the conditions of sharp convex point and larger initial clearance. These forms of dynamic characteristics can be effectively used to diagnose the fixed-point rub-impact faults.     

Dynamic modeling and vibration control of a large flexible space truss

Meccanica - Dynamic equivalent modeling is convenient to the vibration controller design of large space truss structures. Consequently, it is important to study the effectiveness of designed...     

新型固态荧光增强的萘酰亚胺衍生物的合成与发光行为

萘酰亚胺及其衍生物由于其独特的光物理性质、光稳定性和电子接受能力而广泛应用于荧光传感器、光电材料等领域。本文设计并合成了一种新型固态荧光增强的萘酰亚胺衍生物,其结构经¹H NMR、 ¹³C NMR、 MS和IR表征,并研究了该化合物的固态和溶液发光行为。结果表明：该化合物不仅在稀溶液中表现出可调谐的可见光发射,而且表现出固态荧光增强,这种行为与ACQ和AIE发色团明显不同。     

测定钢丝杨氏模量的实验方案研究

针对静态拉伸法测杨氏模量的实验方法,改进钢丝微小伸(缩)量的测量方案,选用一次性增(减)砝码的测量方案,使钢丝得到充分的拉伸(或收缩).由光放大原理分析,合理选择负重砝码,适度控制光杠杆镜面与望远镜的距离,使得望远镜中标尺刻度变化量的测量质量进一步提高.通过实验原理及其不确定度分析,结合测量数据,用置信概率为95%的不确定度对测量数据及杨氏模量的实验结果进行分析与评定,能得到更加合理的实验结果.     

一氧化氮荧光分子探针

一氧化氮（NO）在生物体中扮演重要的角色,对其选择性识别引起了人们极大的兴趣。本文综述了两类NO荧光分子探针的研究进展,即含金属离子的NO荧光分子探针：如Co(Ⅱ)、Fe(Ⅱ)、 Ru(Ⅱ)、Rh(Ⅱ)和Cu(Ⅱ)配合物作为荧光打开的NO分子探针;邻苯二胺类荧光分子探针：如2,3-二氨基萘（DAN）、二氨基荧光素衍生物（DAFs）、二氨基罗丹明衍生物（DARs）、硼二吡咯甲基衍生物（BODIPY）和三碳菁衍生物（DAC）等。