柴油机主要部件冲击响应时域分析

通过对某型柴油机抗冲击性能进行评估,给出了对于这种复杂机械系统动力学建模的原则和依据,考虑到柴油机中包含的大量非线性接触关系,采用时域模拟法对其抗冲击性能进行评估.基于BV043/85标准对柴油机进行垂向冲击响应时域分析,通过主要部件的应力响应总结了抗冲击薄弱环节,通过主要部件的运动响应和轴承油膜压力评估了其正常工作能...     

一种应用于平面拦截问题的导弹导引律设计

针对导弹平面拦截问题,利用弹-目几何关系设计出一种新的用于攻击机动目标的非线性几何导引律NGG(nonlinear geometric guidance)。首先建立导引关系式,通过弹目运动关系得出平面拦截问题的非线性相对运动方程,然后由数学方法推导出成功拦截的条件。仿真研究表明,对高机动目标拦截效果明显,并与用于打击机动目标常用的扩展比例导引律APN(augmented proportional navigation)相比较,在初始发射弹道倾角比较大时,NGG导引的脱靶量明显小于APN导引。     

地质专题与新闻片制作应用非线性编辑系统的优势与前景

计算机技术应用的普及,为各行各业都开辟了以计算机为平台建立自己的工作程序的新的工作方式。而现在在非线性的系统中进行处理的时候,只要选择所要用的字,再选择“镜像”的选项,字体就会自动的变为镜像了。把编辑好的新闻片,通过计算机数字压缩技术,可以直接存放在硬盘上面,再通过刻录软件利用刻录机将已经编辑制作好的新闻或专题片录像带刻录在DVD光盘上。过去录像带120分钟价格约30元,而1张光盘成本仅仅2元,其价格是录像带的1/16,同样录像带需要大量空间存放,而光盘的存放也就是一盘录像带的1/20。     

非线性函数协方差传播公式的两种方法及其等价性

本文将非线性观测值函数泰勒级数展开，并取至二次项，得到线性一二次项形式。一方面在线性空间[L，M]］n中推导出含有二次项的非线性函数的广义协方差传播公式，该公式在形式上类似于经典欧氏空间中的协方差传播公式；另一方面又利用矩阵理论等推导出含有二次项的非线性函数的协方差传播公式的矩阵形式。分析并证明了二者的等价性及与经典传播公式间的关系。     

齿轮全齿磨损的胞映射全局动力学分析

含故障齿轮非线性系统的全局性态分析是对齿轮正确故障诊断的状态依据,运用能够反映非线性系统复杂全局性态的简单胞映射方法,把故障齿轮非线性系统所处的状态空间转化为胞空间,对齿轮非线性系统在不同程度磨损故障状态下的动力系统的全局特性进行了分析,通过对比不同程度故障下系统的吸引域及其吸引胞,得到磨损故障齿轮非线性系统全局特性的变化规律,为齿轮非线性系统的故障诊断提供了另一种研究思路和方法。     

An alternating optimization approach for mixed discrete non-linear programming

This article contributes to the development of the field of alternating optimization (AO) and general mixed discrete non-linear programming (MDNLP) by introducing a new decomposition algorithm (AO-MDNLP) based on the augmented Lagrangian multipliers method. In the proposed algorithm, an iterative solution strategy is proposed by transforming the constrained MDNLP problem into two unconstrained components or units; one solving for the discrete variables, and another for the continuous ones. Each unit focuses on minimizing a different set of variables while the other type is frozen. During optimizing each unit, the penalty parameters and multipliers are consecutively updated until the solution moves towards the feasible region. The two units take turns in evolving independently for a small number of cycles. The validity, robustness and effectiveness of the proposed algorithm are exemplified through some well known benchmark mixed discrete optimization problems.     

Mid-infrared supercontinuum generation in tapered As2S3 chalcogenide planar waveguide

Abstract

We numerically demonstrate mid-infrared supercontinuum generation in a non-uniformly tapered chalcogenide planar waveguide. This planar rib waveguide of As₂S₃ glass on MgF₂ is 2 cm long with increasing etch depth longitudinally to manage the total dispersion. This waveguide has zero dispersion at two wavelengths. The dispersion profile varies along the propagation distance, leading to continuous modification of the phase-matching condition for dispersive wave emission and enhancement of energy transfer efficiency between solitons and dispersive waves. Numerical simulations are conducted for secant input pulses at a wavelength of 1.55 μm with a width of 50 fs and peak power of 2 kW. Results show this proposed scheme significantly broadens the generated continuum, extending from ~1 to ~7 μm.     

Two modelling data analytical methods applied to optimise the preparation of norcantharidin chitosan nanoparticles

In our study, the non-linear regression model and artificial neural networks (ANNs) were used to optimise the preparation of the loading norcantharidin chitosan nanoparticles (NPs) by ionic cross-linkage. Two major indexes, the particle size and the entrapment efficiency of the drug vehicles were synchronously optimised according to the normalised value calculated referring to the weights of the indexes and factors. For the purpose, a multiple regression model was constructed for fitting several preparation factors, including the low molecular weight of chitosan (LCS), sodium tripolyphosphate (TPP) concentrations and the temperature of the ionic cross-linkage reaction. Each of the level values in the factors was arranged using the L₉(3⁴) table and their linear weighted sum of the normalised value was taken as optimised object. A back-propagation (BP) network (3 × 7 × 2) in ANNs was created and trained for further checking the optimal results and the trained network was applied to simulate the experiment system and screen the optimal conditions. Finally, when the weights of temperature, particle size and entrapment efficiency were 0.1, 0.4 and 0.5, respectively, the best preparation condition of NPs was obtained as 131 ± 7 nm of particle size and 45.12% of entrapment efficiency at 40°C.     

鲁地拉水电站地下厂房岩壁吊车梁设计

鲁地拉水电站工程地下厂房吊车梁采用岩壁吊车梁结构。设计时采用《地下厂房岩壁吊车梁设计规范(Q/CHECC 003-2008)》推荐方法对梁体受拉锚杆的截面积、锚固长度以及梁体的抗滑稳定等进行了详细的计算。此外还应用ANSYS程序,采用二维、三维非线性有限单元法,精细模拟了围岩、梁体、锚杆以及岩壁吊车梁与岩体的接触面,对岩壁吊车梁的受力特性进行了系统的计算分析。数值仿真分析结果表明采用接触面单元、锚杆单元,充分考虑了梁体与围岩之间的张开、接触、摩擦以及受拉锚杆与围岩的相互作用,较好地反映了岩壁吊车梁在各种工况下的工作性态及支护机理,对其他工程的岩壁吊车梁的稳定性分析、支护设计有较好的借鉴和指导作用。     

位置敏感探测器(PSD)的非线性补偿技术

介绍了二维枕型位置敏感探测器(PSD)的工作原理和非线性的成因.根据PSD的非线性特点提出了双边线性插值补偿法对PSD的非线性进行补偿.在不增加硬件成本的前提下大幅度提高了PSD的线性度,扩大了PSD的有效使用面积.实验表明:补偿后PSD获得了很好的线性度.