剑杆织机打纬凸轮几种运动曲线的动态响应及比较

本文主要针对双相剑杆织机凸轮式打纬系统的特性,研究了其在不同正余弦函数输入下的动态响应,作出相应比较,并在此基础上,提出了构造新型凸轮运动曲线的可能性。     

正则半群的模糊同余三元组

考虑一般的正则半群上的模糊同余，定义了正则半群的模糊同余三元组的概念，证明了正则半群上的模糊同余由它的模糊同余三元组惟一确定，进而得到正则半群上的模糊同余集和模糊同余三元组集之间存在一一对应关系。     

3×t阶Kirkman三连系的构造法

进行了6n+3阶Kirkman三连系构造方法的探索。并首次构造出81阶Kirkman三连系。阐明了Kirkman三连系的构造思路,介绍了Kirkman三连系的构造过程。     

水轮机模拟装置及最大功率获取控制策略

为了实现水轮机工作特陛的模拟及最大功率的获取,分析潮流能特性,设计了水轮机模拟装置及相应控制策略,通过搭建水轮机模拟装置进行实验,验证水轮机模拟装置的功率转速特性的正确性及最大功率获取控制策略的有效性．     

一类偶数阶Robin型积分边值问题三重正解的存在性

利用Leggett-Williams不动点定理,得到非线性偶数阶微分方程y(2n)(t)=f(t,y(t),y″(t),…,y(2(n-1))(t)),t∈[0,1],满足Robin型积分边界条件y(2i)(0)=∫10ki(s)y(2i)(s)ds,y(2i+1)(1)=0,i=0,1,…,n-1的边值问题三重正解的存在性.     

An Efficient Differential Space-time Modulation Method Based on Amicable Orthogonal Design

The authors propose an amicable-orthogonal-design-based differential space-time block code (ADSTBC) for multiple antennas. Compared with the existing differential modulation designs, their scheme imposes no restrictions on underlying signal constellation, and therefore can improve the spectral efficiency by exploiting efficient modulation techniques such as QAM and APSK. They then derive a non-coherent maximum-likelihood decoder (MLD) for flat Rayleigh fading channels. The amicable orthogonal property of data matrices assures that MLD has very low bit error rate and linear decoding complexity. Particularly, in two special cases of ADSTBC, the simplified MLDs which can greatly reduce the implementation cost are derived.     

限制李三系的若干性质

把群的Frattini理论拓展到限制李三系中,给出了限制李三系的Frattini-子系、Frattini p-子系、Frattini-理想和Frattini P-理想的一些性质.同时,给出P-可解限制李三系的性质,得到限制李三系交换的一些充分条件,并讨论了户-幂零限制李三系.     

李三系的泛覆盖

研究了李三系的中心扩张和3-上循环的关系,引人了李三系的泛覆盖,并建立了李三系存在泛覆盖的充要条件.     

Applications of Wigner high order spectra in feature extraction of acoustic emission signals

The characteristics of typical AE signals initiated by mechanical component damages are analyzed. Based on the extracting principle of acoustic emission（AE） signals from damaged components,the paper introduces Wigner high-order spectra to the field of feature extraction and fault diagnosis of AE signals. Some main performances of Wigner binary spectra,Wigner triple spectra and Wigner-Ville distribution （WVD） are discussed,including of time-frequency resolution,energy accumulation,reduction of crossing items and noise elimination. Wigner triple spectra is employed to the fault diagnosis of rolling bearings with AE techniques. The fault features reading from experimental data analysis are clear,accurate and intuitionistic. The validity and accuracy of Wigner high-order spectra methods proposed agree quite well with simulation results. Simulation and research results indicate that wigner high-order spectra is quite useful for condition monitoring and fault diagnosis in conjunction with AE technique,and has very important research and application values in feature extraction and faults diagnosis based on AE signals due to mechanical component damages.