低空目标噪声模型

低空目标噪声模型李云，贾民生（青岛大学计算中心，青岛２６６０７１）关键词：噪声模型；地空武器系统在地空武器系统大型仿真实验中，要求加入检飞试验中测量低空目标所带来的噪声误差信号．传统的方法是将磁带机记录的噪声信号直接加入仿真模型中，这种方法极不方便，...     

An approach to the detection of underwater remote target

An approach to the detection of underwater remote target by estimating its backscattering coefficient is presented. The key to this approach is that the echo signal is represented in state-variable model and the back-scattering coefficients of target are contained in dynamic noise of this model, thus underwater target can be detected by estimating this dynamic noise, i.e., deconvolving this model. When all noise statistics are a priori known, an optimum deconvolution algorithm based on the optimum state filter is derived, or else, an adaptive deconvolution algorithm based on the adaptive state filter of alternatively estimating the vector state and the noise statistics is developed. In the final simulation test, an echo signal with SNR equal to -6.1 dB is proceeded using the aforementioned two deconvolution algorithms, respectively, and the results demonstrate good performance of the approach.     

关于李萨如图形讨论的小结

对《大学物理》和其它一些刊物上多年来关于李萨如图形的讨论作了归纳和分析。     

Phase Transitions in the Early Universe with Negatively Induced Supergravity Cosmological Constant

We consider that the observable cosmological constant is the sum of the vacuum （Avac） and the induced term （Aind - 3m^2/4） with m being the ultra-llght masses （≈ Hubble parameter） implemented in the theory from supergravities arguments and non-minimal coupling. In the absence of a scalar buildup of matter fields, we study its effects on spontaneous symmetry breaking with a Higgs potential and show how the presence of the ultra-light masses yields some important consequences for the early universe and new constraints on the Higgs and electroweak gauge bosons masses.     

负关联噪声驱动下单模激光的定态分析

研究了负关联的加法和乘法高斯白噪声驱动下单模激光损失模型的定态情况。文中推导了负关联情况下，定态时的激光场幅的几率分布，光强的平均值，光强的协方差以及光强的偏斜率。并和文献〔１，２〕中正关联时的定态分析作了比较，发现了有意义的新现象。     

脉冲离散效应对光纤中基于交叉相位调制的脉冲压缩的影响

通过数值模拟，分析了脉冲离散效应对单模光纤正群速色区基于暗孤子交叉不相位调制的脉冲压缩的影响，并提出了减轻这种影响的办法，作者发现，即使暗孤子与被压缩脉冲的中心波长相差很小，离散效应对脉冲压缩的影响也很大，离散效应不仅导致脉冲压缩比的减小和压缩后脉冲峰值功率的降低，而且还导致脉冲压缩所需最佳光纤长度的增加以及压缩后的脉冲呈现不对称性，还发现，若采取本文提出了的非同步耦合法，则可以明显地弥补离散效应     

突体剖面线型的流噪声机理分析和试验研究

本文在分析突体马蹄涡和湍流脉动压力特性的基础上，在中国船舶科学研究中心０３Ｂ水筒，试验比较了不同剖面线型的突体模型流动噪声，降噪效果３－５ｄＢ，提出了突体部面低噪声设计的实验依据和具体方法。     

两类求解y“=f（x,y）具有极小相位延迟的显式方法

本文提出了两类数值积分二阶周期性初值问题ｙ〃＝ｆ（ｘ，ｙ），ｙ（ｘ０）＝ｙ０，ｙ（ｘ０）＝ｙ０具有检小相位延迟的显式两步法。这些方法推广和改进了文献「１」１－「７」中的某些方法。数值试验表明本文中的某些方法优于「１」－「７」中的某些方法。