基于PCNN改进算法的手写体识别研究

脉冲神经网络(PCNN)被广泛应用于图像处理、模式识别等领域。提出了一种基于PCNN的凹点检测改进算法。首先改进神经元激励函数,并利用小波收缩法去噪,保持图像的层次性,然后通过凹点检测识别手写体。实验结果表明,提出的方法能有效提高手写字母的识别率,尤其是在噪声环境下,识别率得到大幅提升。     

图像复原的Contourlet收缩与广义全变分正则化方法

建立了广义全变分(total variation,TV)模型,分析正则项在复原算法中的作用.分别从图像的平坦区域和边缘区域入手,在平坦区域图像各向同性扩散,在边缘区域则要满足各向异性扩散,从理论上对两种情形下的扩散做深入分析,推导出广义TV模型满足的一些条件,为了防止高噪声情形下复原模型失效以及克服方块效应,在正则项中引入了 Contourlet收缩,它是一种多分辨的、局域的、多方向的更稀疏的图像表示方法,正则项中引入的Contourlet收缩具有去噪和提取图像重要信息的作用,Contourlet收缩与广义TV正则化相结合,兼顾了图像的光滑性和边缘保持,特别是在图像严重模糊、噪声越多的情形下,更加体现了这种算法比改进的TV模型有效.     

高收缩共聚酯合成性能与成纤性能研究

通过共聚酯PEIT(间苯二甲酸、对苯二甲酸、乙二醇共聚物)的合成及其全拉伸丝(FDY)纺丝的成功实验,研究了高收缩PEIT共聚物合成工艺中共聚组分间苯二甲酸(IPA)的摩尔百分数对共聚酯PEIT的玻璃化温度、熔点的影响,探讨了该PEIT共聚物的结晶性能及其纺丝工艺条件对高收缩纤维性能的影响。     

Influences of reinforcement on differential drying shrinkage of concrete

Shrinkage strain of concrete specimen with different reinforcement configuration was measured at various depths from the exposed surface by using several pairs of displacement sensors. Only one surface of the concrete specimen was exposed to dry condition during the experiment. The results show that differential shrinkage strain occurs in both plain and steel reinforced concrete specimens according to depths from the exposed surface. A higher reinforcement ratio results in a greater restraint against shrinkage of concrete nearby reinforcement rebar and a worse differential shrinkage strain distribution in the concrete specimen. The restraint against shrinkage of concrete becomes lower with the increasing distance from reinforcement rebar. Under the same reinforcement arrangement, a higher free shrinkage of concrete leads to a stronger restraint against shrinkage and a higher shrinkage stress formation in local concrete. The relationship between shrinkage strain and reduction of relative humidity in reinforced concrete structure is far different from that in plain concrete.     

风化细砂改良膨胀土胀缩特性室内试验研究

针对目前膨胀土化学改良方法存在的缺陷,提出了一种采用风化细砂对膨胀土胀缩特性进行物理改良的方法．通过在膨胀土中掺入不同比例的风化细砂,并进行膨胀试验和收缩试验,研究不同掺砂比例对膨胀土的膨胀和收缩指标的影响．通过对不同比例掺砂膨胀土的胀缩特性数据分析发现,随着掺砂比例的增加,膨胀和收缩指标减小．当掺入风化细砂的比例达到10％时,对胀缩指标影响最显著,且胀缩总率为0．67％,自由膨胀率为31％,达到路基填料的标准．综合经济性和实用性考虑,最佳掺风化砂比例为10％．     

精密接插件注射成型工艺参数的优化设计

以某厂生产的精密塑件——电子接插件为例，通过分析该塑件体收缩变形和翘曲变形的原因，以正交试验为设计准则，利用Moldnow软件对各种工艺参数组合进行注射成型过程的模拟。研究表明，注射速率对体收缩变形的影响最为显著，而保压压力对翘曲变形起主导作用。并在正交试验的指导下优化工艺参数，使体收缩变形和翘曲变形分别降为原来的57．9％和85．6％，分析结果与生产实际吻合。     

某厂大尺度楼盖结构裂缝检测及成因分析

对某厂大尺度混凝土楼盖开裂情况进行检测，并通过对混凝土板贯穿性裂缝进行计算及成因分析，表明除了荷载引起裂缝外，混凝土收缩及温度应力也是产生裂缝的主要原因．提出了控制裂缝的设计措施．     

Experimental and numerical investigation of the debonding interface between an old concrete and an overlay

The paper focuses on debonding propagation along an interface, notably on the major influence of the interlocking between the two faces of the debonding interface. The aim of the study is to obtain the data necessary for relevant and efficient debonding modelling. The work associates experiment and simulation with the purpose of quantifying the interlocking along the interface. The overlay material investigated was a fibre reinforced mortar (FRM). Direct tension tests of notched FRM specimens were firstly conducted to obtain the tensile strength and the residual normal stress—crack width relationship. Its Young's modulus was determined from compression tests. The substrate-overlay interface was investigated by direct tension tests and flexure tests performed on composite substrate-overlay specimens. The direct tension tests provided the interface tensile strength and the relationship between debonding-opening and residual normal tensile stress. Three point flexural static tests informed on the structural behaviour of the interface. The debonding interface propagation was monitored using a video-microscope with a maximum enlargement of ×175. Using the identified and quantified parameters, modelling of the above mentioned static tests was carried out by the finite elements method using CAST3M code developed in France by CEA (Centre for Atomic Energy). The comparison of modelling and experiment results shows a good coherence and proves the important role of interlocking on the debonding mechanism.     

钢筋混凝土裂缝机理与控制措施

钢筋混凝土裂缝分析与控制,全文共4部分:1、裂缝是不可避免而又可以尽量减轻的自然灾害;2、收缩裂缝分析及控制;3、温度收缩裂缝分析及控制;4、裂缝控制的综合技术措施。较全面地论述了钢筋混凝土裂缝机理及控制措施,文末附有100多篇参考文献。