复杂载荷历程下疲劳寿命的预测方法

近年来局部应力-应变法在疲劳寿命预测中,越来越受到人们的高度重视。但普通的Neuber局部应力-应变法对于每一名义应力变程都需要建立新的坐标原点,并解非线性方程组。为此本文对其算法技巧进行了研究。算例表明,本文提出的新算法,能保证足够精度,程序得以简化,运算速度大幅度提高。     

扭矩的随机模拟方法及雨流计数算法

本文引入了Ｍｏｎｔｅ－Ｃａｒｌｏ方法，模拟初轧机主传动系统的随机振动扭矩，将其同轧制静扭矩叠加，构造了扭矩─时间历程的模拟模型；同时，提出了一种修正的雨流计数法，并给出了相应的算法。     

Photons in the Non－uniform Optical Waveguide Propagate along z－axis in Spiral Form

ＰｈｏｔｏｎｓｉｎｔｈｅＮｏｎ－ｕｎｉｆｏｒｍＯｐｔｉｃａｌＷａｖｅｇｕｉｄｅＰｒｏｐａｇａｔｅａｌｏｎｇｚ－ａｘｉｓｉｎＳｐｉｒａｌＦｏｒｍ￥ＺＨＡＮＧＪｉｎｗｅｉ（ＪｉｎａｎＵｎｉｖｅｒｓｉｔｙ，Ｇｕａｎｇｚｈｏｕ５１０６３２，ＣＨＮ）Ａｂｓｔｒ...     

一般压缩态与非经典效应

本文引进谐振子体系一般压缩态,讨论它的压缩特性、反聚束特性及其产生,并给出各种极限下的结果。     

早期产品可靠性预计存在的问题及对策

针对早期产品在可靠性预计过程中存在的普遍问题,以具有代表性的产品为例,给出了相应的对策.     

基于CPLD的单光子计数系统研究

介绍基于CPLD和USB接口的单光子计数系统,通过软硬件技术的结合,实现对超短脉宽的光脉冲信号的采集和输出.系统采用CPLD芯片、单片机和USB接口芯片,进行高速数据的采集,并在计算机中使用图形界面显示和控制,操作更为方便.实验证明,系统具有响应速度快、低成本、低功耗、可靠性高等优点.     

Typical models: minimising false beliefs

A knowledge system S describing a part of real-world does, in general, not contain complete information. Reasoning with incomplete information is prone to errors since any belief derived from S may be false in the present state of the world. A false belief may suggest wrong decisions and lead to harmful actions. So, an important goal is to make false beliefs as unlikely as possible. This work introduces the notions of typical atoms and typical models, and shows that reasoning with typical models minimises the expected number of false beliefs over all ways of using incomplete information. Various properties of typical models are studied, in particular, correctness and stability of beliefs suggested by typical models, and their connection to oblivious reasoning.     

Determination of fragments of multiaxial service loading strongly influencing the fatigue of machine components

The paper presents a method for determination of multiaxial load segments from original service histories, where the loaded machine part is meaningfully subjected to fatigue damage. These load segments are directly separated from a service-loading history, which can be of a random character. Typical procedures used for fatigue life assessment under multiaxial random loading are implemented to perform this task. While reduction from the multiaxial stress state to the equivalent uniaxial one, application of the linear multiaxial fatigue failure criteria was proposed. The equivalent stress history is subjected to the rainflow cycle-counting method, which allows to determine the amplitudes and mean values of counted cycles, their occurrence moment and time of duration. Influence of the stress mean value was taken into consideration with the Morrow's model. On the assumption of the linear Palmgren–Miner hypothesis of damage accumulation and the stress–life fatigue characteristics of the material, the damage-time function was determined. The load segments, where the influence on the material fatigue was significant, were determined on the basis of the fixed damage-intensity level and the proposed damage-intensity function. The presented method was studied on a hook loaded with two independent forces. FEM program which has the possibility to perform fatigue analysis was used during the computation for determining the expected place of crack initiation. The service-loading course was compressed to shorter one, so that only a small decrease of the fatigue damage in comparison with full length of the original service loading was observed. The proposed method seems to be right for preparing multiaxial loading histories in order to cut down the fatigue tests, especially in the case when the correlation between particular loading channels is very important.     

集成U-Net方法的无人机影像胡杨树冠提取和计数

塔里木河流域的胡杨林是该荒漠区域典型的森林资源,胡杨树冠大小和株数信息对塔里木河流域森林资源监测、生态保护和恢复具有重要意义。由于该流域乔灌草植物群落分布的复杂性,传统方法很难实现胡杨树冠的精准分割和大范围的株数提取。以塔里木河中游胡杨林为研究区,选取几块典型胡杨林区域,提出集成深度学习和分水岭分割的处理方法,对密集胡杨树冠的精准分割和单株胡杨的提取进行了深入探讨。首先,将无人机影像（空间分辨率0.16 m）无缝拼接生成正射影像;采用U-Net卷积神经网络对胡杨树冠覆盖区域进行精准分割;在U-Net模型分割的基础上使用标记分水岭方法对密集胡杨树冠进行自动再分割和单株计数,计算出所选研究区的胡杨株数并精准定位。结果表明U-Net卷积神经网络对胡杨的所有树冠区域提取的平均精度可达94.1%,在胡杨树冠覆盖区域识别分割的基础上,用标记分水岭分割方法对胡杨单木计算总体精度为93.3%。研究认为,结合深度学习和标记分水岭方法为自动化大范围森林资源监测提供了新思路和借鉴经验。     

基于QNX的操作监控平台的设计与实现

根据QNX的Photon微图形用户接口(microGUI)的运行机理，采用自定义事件、伪终端和telnet技术、动态分配内存等方法，解决了EAST极向场电源控制系统实时网络通信、启动和终止远程进程、动态绘制波形等关键问题，实现了一个友好、高效的操作监控平台，为EAST极向场电源的稳定运行提供了有力保障。