THE METHOD OF THE RECIPROCAL THEOREM OF FORCED VIBRATION FOR THE ELASTIC THIN RECTANGULAR PLATES(Ⅲ)—CANTILEVER RECTANGULAR PLATES

In this paper,applying the method of the reciprocal theorem,we give the stationarysolutions of the forced vibration of cantilever rectangular plates under uniformly distributedharmonic load and concentrated harmonic load acting at any point of the plates,the figuresand tables of number value of bending moment and the deflection amplitudes as well.     

The correlation functions near intermittency in a one-dimensional Piecewise parabolic map

Piecewise parabolic maps constitute a family of maps in the fully developed chaotic state and depending on a parameter that can be smoothly tuned to a weakly intermittent situation. Approximate analytic expressions are derived for the corresponding correlation functions. These expressions produce power-law decay at intermittency and a crossover from power-law decay to exponential decay below intermittency. It is shown that the scaling functions and the exponent of the power law depend on the kind of the correlations.     

信号侦察中的跳频信号识别方法

为了解决跳频设备已经大量装备而对跳频信号的侦察识别仍然困难的问题,作者提出了两种跳频信号识别方法,包括最大相关处理法和时间相关统计法.在对跳带内的信号进行数字信道化处理后,再经过最大相关处理,时-频图上的跳频信号的分布情况将会变得非常清晰;时间相关统计法是充分利用跳频信号在时间上的断续性和每跳间的连续性来识别跳频信号.经过实验验证,上述两种识别方法的使用,在跳频信号的侦察识别上效果非常明显.     

一种有效降低OFDM系统信道估计复杂度的方法

在应用于OFDM系统的信道估计方法中,维纳滤波是一种估计性能较好的算法,但是该方法计算复杂度大,不利于实现.本文基于块状导频方式,提出了选取相关子载波的相关系数法来简化维纳滤波的信道估计方法,该方法在估计性能损失不大的情况下,有效地降低了计算复杂度.文中在慢时变信道环境下对该方法进行了性能仿真,并对仿真结果进行了讨论.     

高阻恒流LED产生亚泊松光的理论研究

本文研究高阻恒流源驱动的光发射二极管（ＬＥＤ）的输出光场的振幅噪声压缩与电，光量子效率，漏电流效应，泵浦残余噪声频率的关系，指出高阻恒流技术不仅使任意纵模产生振幅噪声压缩，而且由于仅在高阻恒流下各纵模间存在负量子相关，使得ＬＥＤ总输出光场的振幅噪声压缩加深。     

1H NMR studies of molecular relaxations of poly-1-butene

The temperature dependance of the proton NMR line shape, T₁ and T_1ρ of isotactic poly-1-butene forms I, I′, II, and III have been studied between 100 and 400 K (up to melting). The usual line shape decompositions concerning rigid vs. crystalline and mobile vs. amorphous phases are discussed. The rigid-lattice second moments were calculated introducing a fast rotation of the methyl group. Complex spin-lattice decays were analyzed as a continuous distribution of rates. Relaxation behavior was analyzed in terms of a Williams-Watt correlation function. Motions in the crystalline parts of samples in forms II and III very similar to the amorphous one were revealed, leading us to compare form II to a condis crystal during the crystal form transformation. © 1995 John Wiley & Sons, Inc.     

Optimal nonlinear filtering with constraints—Part II

The impulse response of nonlinear systems with bounded memory and energy have been considered. On the base of the minimum mean square error criterion a generalization of the Wiener-Hopf equation is developed.     

Zernike多项式展开系数的时间相关性

 分析了受大气湍流扰动的光波波前在系统接收孔径上的Zernike多项式展开系数的时间相关性,在此基础上进一步分析了从不同方向到达系统接收孔径的光波波前整体倾斜之间的相关性,并给出了光波在水平均匀大气中传播时的结果。     

透镜抛光机主轴转速与摆架摆速的匹配

从计算得出的浮动上模作往复周期摆动时工件表面上任一点的相对线速度表达式看出，线速度幅值是一个多变量函数，在这些参数中，只有主轴转速与摆架摆速是机床本身的固有参数，从均匀抛光角度出发，提出主轴转速与摆架摆速匹配的观点，为抛光机换代设计提供了依据。     

Performance Analysis of the Spectral Correlation Discriminator Array

Mobile communications suffer from cochannel interference, adjacent channel interference and fading. The cell capacity or the number of users per cell is limited by the interference. In this paper we analyze a new blind adaptive array structure called the spectral correlation discriminator array (SCDA), designed to reject cochannel interference for advanced mobile phone service (AMPS) signals. The blind adaptive array exploits the spectral redundancy in the AMPS signals which arises due to the presence of the supervisory audio tone (SAT). SCDA is shown to provide an improvement of 25–30 dB in signal-to-interference plus noise ratio (SINR) in static multipath channels and 10–15 dB improvement of SINR in Rayleigh fading channels. The SCDA is compared to the least squares constant modulus array (LSCMA) and is shown to have better signal selectivity properties. The reduction in interference power can significantly reduce the frequency reuse factor.