微表处混合料配合比设计存在的问题及改进

基于现行微表处配合比设计对微表处路段在施工中、施工后发生病害的影响,分析了目前微表处混合料配合比设计存在的问题研究了将飞散试验引入微表处混合料配合比设计的可行性,并提出改进微表处配合比的设计方法     

电磁材料弧形界面裂纹SH波散射的远场特性

分析了电磁材料弧形界面裂纹SH波散射的远场特性。根据波函数展开法将所研究的混合边值问题转化为对偶级数方程组,通过引入位错密度函数,进一步将问题归结为第一类Cauchy奇异积分方程。在此基础上,导出了远场散射模式（SFFP）和散射截面（SCS）的表达式,并详细考查了入射方向、裂纹张开角及载荷组合对远场散射特性的影响。研究成果对电磁构件的设计及电磁材料内裂纹的识别具有理论与应用价值。     

声场计算中一类奇异积分的数学处理

针对任意形状、任意阻抗表面的水下目标散射声场的计算问题,提出其中一种类型奇异积分数学处理的新方法,并给出计算这类奇异积分的级数公式。     

Wave scattering by undulating bed topography in a two-layer ocean

The problem of wave scattering by undulating bed topography in a two-layer ocean is investigated on the basis of linear theory. In a two-layer fluid with the upper layer having a free surface, there exist two modes of waves propagating at both the free surface of the upper layer and the interface between the two layers. Due to a wave train of a particular mode incident on an obstacle which is bottom-standing on the lower layer, reflected and transmitted waves of both modes are created by the obstacle. For small undulations on the bottom of the lower layer, a perturbation method is employed to obtain first-order reflection and transmission coefficients of both modes for incident wave trains of again both modes in terms of integrals involving the bed-shape function. For sinusoidal undulations, numerical results are presented graphically to illustrate the energy transfer between the waves of different modes by the undulating bed. U. BASU was born in 1949. She is a professor in the Department Applied Mathematics, Calcutta University, India. Her current research interests include water wave problems, continuum mechanics, etc.     

Effects of intake flow on the spray structure of a multi-hole injector in a DISI engine

The spray characteristics of a 6-hole injector were examined in a single cylinder optical direct injection spark ignition engine. The effects of injection timing, in-cylinder charge motion, fuel injection pressure, and coolant temperature were investigated using the 2-dimensional Mie scattering technique. It was confirmed that the in-cylinder charge motion played a major role in the fuel spray distribution during the induction stroke while injection timing had to be carefully considered at high injection pressures during the compression stroke to prevent spray impingement on the piston.     

舰船目标RCS水面模拟试验及其应用探讨

舰船目标作为海上运行的武器平台,其电磁散射的最本质特征体现为目标与海面环境一体化的复合散射。在舰船目标雷达波隐身性设计中,需要开展模拟RCS试验来验证方案可行性。针对舰船所处海面环境的特点,采用双射线追踪方法分析了随机粗糙海面对舰船散射回波特性的影响,提出了关于舰船雷达波隐身设计流程的建议,论证并指出在技术设计阶段需要用接近实际环境的方法进行水面环境舰船隐身设计验证,结合数值仿真与本体RCS试验,掌握并控制舰船隐身性指标和强散射"要害点",并从场地开阔性、测试方法等方面提出了舰船目标RCS水面模拟试验的测试要求,从RCS指标设计验证、强散射中心分析、总体多专业协同设计等方面,探讨了模拟试验方法的应用和发展方向。     

基于散射特性的混装箔条云RCS计算与仿真

目前对箔条云雷达散射截面(RCS)计算多采用经验公式,难以满足混装箔条弹RCS的精确计算需求,针对这一问题提出了基于散射特性的混装箔条云RCS精确计算方法。结合单根箔条的散射特性和姿态特性,对不同极化条件下单根箔条和箔条云的RCS进行精细化求解,为箔条弹的配比和RCS计算提供了模型基础。MATLAB仿真结果表明,模型能够满足混装箔条云RCS的精确计算,为精确研究箔条干扰提供了数据支持。     

单根箔条偶极子电磁散射特性模型研究

根据散射原理、雷达截面积的物理意义,推导出箔条偶极子雷达截面积的定义式,分析出在不同极化波入射条件下,偶极子的雷达截面积精确计算公式。利用散射矩阵,讨论了散射特性。推导出不同空间取向偶极子的平均雷达截面,并给出计算结果。     

铁路道碴瞬态电磁散射特性分析

引用离散随机媒质结构来模拟铁路道碴的分布情况，采用在ＦＤＴＤ法的差分网格中进行随机填充来实现铁路道碴的计算模拟模型，并求解其瞬态电磁散射场。通过对该散射场的处理，提取出道碴的非相关散射场，然后再对该非相关场进行分析，得出了可描述道碴分布状况的电磁参量。数值分析结果显示，该参量与道碴空隙率之间在一定范围内具有指数关系。这表明，用电磁方法来探测铁路道碴的空隙率是可能的。