一种简单的线条特征抽取算法

本文阐述了一种简单的线条特征法,该算法是通过边缘检测,细化、符号化三过程实现的,而符号化过程是借助于边缘检测的方向码通过扫描、连接、补缺三步骤完成的,根据所选择的控制参数,可以形成基于最短线条长度的各种层次的符号化描述,灵活性强,速度快,效率高,特别适用于双目立体视觉的研究中,用来获得线条基元。     

催化裂化分馏塔塔顶循环回流线腐蚀原因分析

文章针对催化裂化分馏塔塔顶循环回流线短时间减薄的特殊情况,进行了腐蚀原因分析。根据回流线所处工况及腐蚀产物分析,指出主要是HCl-H_2S-H_2O腐蚀引起的。另外,该回流线局部无保温层,硫酸露点腐蚀也是原因之一。在采取提高返塔温度等措施后,于2006年初进行测厚,未发现壁有减薄现象发生。     

蒸汽发生器炉管减薄规律初探

在4台蒸汽发生器辐射段炉管上分别选取多点进行管壁厚度测量，并根据测厚结果进行统计分析，找出在用蒸汽发生器的炉管管壁减薄规律：受热强度越大且位于蒸发段的炉管管壁减薄程度越明显。这是炉管长期处于高温环境下发生蠕变变形所致。如果再加上炉管的介质流动不畅或管壁结垢等因素，这个部位就容易发生炉管鼓包或爆管事故。爆管发生时破口特征为纵向破裂，表面有氧化皮。为保证蒸汽发生器安全、经济运行，要作好炉管蠕变变形测量；要对超期运行的炉管进行材质鉴定，作出金相分析；要保证炉管焊接质量，作好焊缝探伤，以及加强水质管理和炉管状态监测等。     

含局部减薄缺陷管道的极限载荷与安全评定

运用正交实验设计和弹塑性有限元分析相结合的方法 ,对含局部减薄缺陷压力管道的极限载荷进行了研究 ,分析了局部减薄缺陷对管子极限载荷的影响因素。研究结果表明 ,缺陷的深度是管子极限载荷 (内压和弯矩 )的主要影响因素 ,而缺陷的周向长度和轴向长度分别对管子的极限内压和弯矩的影响较小。据此研究结果 ,提出了含局部减薄缺陷压力管道在内压和弯矩联合作用下的安全评定方法     

A knowledge-based thinning algorithm

One common defect of thinning algorithms is deformation at crossing points. To solve this problem, a new thinning method, called the knowledge-based thinning algorithm (KBTA), is proposed. It first represents a binary pattern by coded run lengths of the horizontal line segments. Then the relationship between line segments is described quantitatively by another new algorithm which makes use of both forward and backward derivatives. It afterwards identifies the regions where branches of the pattern meet, then extracts their shape features and thins all of them. Knowing the identities of these regions, perfect skeletons can be obtained. Other regions are thinned by an existing algorithm which is based on contour generation. Experiments with a wide variety of binary patterns show that this new technique generates better skeletons than several other well-known algorithms.     

离子减薄诱发的Zr65Al7.5Ni10Cu17.5块状非晶晶化相的相变

用透射电子显微镜研究了锆基块状非晶合金晶化行为，对分别经双喷电解减薄加离子减薄和单纯双喷电解减薄制备的电镜样品进行观察分析，发现离子减薄会导致该合金晶化亚稳相的转变。     

Preparation of (InGa)As/GaAs materials for TEM by one side non-rotation ion beam thinning

A technique is described for the preparation of thin specimens for transmission electron microscopy (TEM) of (InGa)As/GaAs multilayered materials. In this technique, a shielding method is used for selective-area perforation by ion beam thinning. Thin cross-sectional specimen slices are mechanically pre-thinned to about 30 μm and then thinned by ion sputtering from one side of the specimen at a time without rotation of the specimen stage. No direct ion sputtering occurs at the growth surface of the specimen so that a specimen with thin areas containing the desired near-surface structures can be obtained. The recipe for this technique is given in detail. A patterning method for increasing the size of the thin area for TEM investigation is also described. It is shown that a smooth surface can be obtained by sputtering without rotating the stage if obstacles that produce redeposits onto the sputtered surface are removed.     

Preparation of ceramic fibre TEM cross-sections using ultramicrotomy and ion beam thinning methods

The preparation of specimens for detailed TEM microanalysis of micrometre-diameter, ceramic fibre cross-sections is described. The starter material is ceramic fibre in powder form and both ultramicrotomy-based and ion beam thinning-based methods are described. Requirements for specimens of uniform and adequate thinness, for easy selection of representative fibre cross-sections within the same specimen and for a reliable and time-efficient preparation method, resulted in choice of the ultramicrotomy-based method and the associated development of a novel extrusion and sedimentation technique of embedding the fibres to provide necessary pre-alignment and packing.     

顶镦弯和侧助推弯管理论与实践

大容量、高参数锅炉的发展,受热面结构紧凑,要求弯管半径小,为了减少钢材的消耗,要求弯管减薄率更小。只有采用助推弯管才能满足以上要求：本文从理论与实践角度详细阐述了助推弯管的原理和应用,并提供了合理的侧助弯和顶镦弯调整参数．