查询词典 crack a book

It includes hardware equipments and foundational theory of the image digitization. This paper expatiates on some digital image processing technologies that the inspecting system may apply to the research and analysis of the collected glass-crack image. Using neighborhood average method and median filter retrains the image noises and make the image edge smooth. Then protract the histogram of the gray image, get the threshold of this image, utilize the threshold method and gray-level slice method to get a binary image, and detect the image edge. Finally calculate the area and perimeter of the glass-crack image, and use the circularity to judge whether this image is a glass-crack image.

本文重点阐述了研究和开发这套玻璃瓶裂纹检测系统所应用到的一些数字图像处理技术，并应用这些技术和方法对采集的裂纹图像进行了处理和分析：应用邻域平均法和中值滤波法来抑制图像的噪声，使图像的边缘平滑；然后绘制出处理过图像的灰度直方图，得到该幅裂纹图像的阈值，利用阈值法和灰度级切片法对裂纹图像进行二值化处理，得到其二值图像，并对图像进行了边缘检测；最后计算出裂纹图像的面积和周长，利用圆形度指标来判断该图像是否为裂纹图像。

The crack spacing of CRCP changes randomly and has a significant impact on the pavement durability and performance. The direct integration method is used to analyze the reliability for crack spacing and width. The results show that the main factors that affected the reliability are the design crack spacing and the variability of parameters. This paper presents a nomogram for reliability calculation.

CRCP的裂缝间距是随机变化的，裂缝间距的不同会对路面耐久性产生显著影响，本文使用直接积分法计算了CRCP裂缝间距的可靠度，并使用蒙特卡罗法进行了对比，分析参数的敏感性，指出影响可靠性最主要的因素是设计裂缝间距及参数的变异性，给出了CRCP可靠度计算诺谟图。

Therefore, on the foundation of abroad research, this text describes the first and second order of crack turning theory, the influence of plasticity zone of crack tip and fracture resistance orthotropy of material to crack propagating trajectory.

因此，本文在国外文献的基础上，对裂纹转折的一阶和二阶理论以及材料裂纹尖端塑性区和断裂韧性各向异性对裂纹扩展路径的影响进行了描述。

The detailed algorithm on analyzing cracks exploration inside blocks is: enriched approximations which describe singular crack tips fields and discontinuous crack faces are employed under the Partition of Unity theory; the enriched nodes surrounding crack tips or faces are respectively mapped with corresponding enriched degrees of freedom, and the solution of all these degrees of freedom is uniformly proceeded by the implicit iteration algorithm of DDA, then fracture and breakage of DDA blocks can be analyzed. The numeric examples show this algorithm is rational and efficient.

为此建立的无网格法裂纹扩展分析算法，采用满足单位分解条件的特殊增强型函数表达裂纹周围应力场的非连续、奇异特性，将对应的扩展自由度动态映射到裂纹周围的节点上，统一按DDA法隐式迭代方式求解，实现块体裂纹扩展和强度分析，相关算例结果显示该算法是合理有效的。

Based on the fictitious crack model and critical crack tip opening displacement CTODc, the precritical crack propagation length △ac of concrete was determined by means of three point bending beams. According to the calculation value of △ac, the effective fracture toughness KunIc of concrete was evaluated.

本文采用虚拟裂缝模型，将临界裂缝尖端张开位移CTODc作为控制参数，利用三点弯曲梁试件通过迭代求得了混凝土裂缝亚临界扩展量的临界值△ac，据此求得了混凝土起裂断裂韧度KiniIc、等效断裂韧度KunIc值。

In the equation, the unknown parameters are determined by the crack initiation angle, the crack length and the angle between the direction of the maximum principal stress and the crack surface.

采用双曲线翼型裂纹路径和试验中所得翼型裂纹路径进行了对比分析，二者吻合得很好，验证了采用双曲线近似表示真实存在的翼型裂纹模型的正确性。

To the crack in the rail surface, the effect of longitudinal location on the distribution of the elastic-plastic stress and strain in the railhead is calculated. The maximum stress around the crack in the rail surface over the yield stress and the steel around the crack has plastic strain.

对于条纹状钢轨表面缺陷，主要计算了不同横截面位置条纹状钢轨表面缺陷对轨头内弹塑性应力场和应变场的影响，条纹状钢轨表面缺陷的存在使其周围最大等效应力超过了钢轨材料屈服极限，导致该位置钢轨发生了塑性应变。

The shearing stress on an octahedral plane is used as a rarameter to analyse crack -producing problems under mixed mode fracture and the crack producing direction is considered as the direction with mimimal displacement from crack tip to plasticity boundary.

本文采用剪应力强度因子作为断裂的参数，分析复合型断裂问题，认为裂纹扩展方向为塑性区最短距离方向。

For the first time the endplate bolted connection's finite element model with the original crack is set up by the singular element, the fracture problem study is introduced to the finite element analyzing. The J integral value and stress intensity factor of the crack tip are calculated by the ANSYS Parametric Design Language program, and the developing of original crack is judged from the K Rule and J Integral Rule.

第一次通过构造奇异单元来建立带初始裂纹的节点有限元模型，将断裂问题的研究引入到端板螺栓节点的有限元分析中，并通过ANSYS软件中Parametric Design Language编程来计算裂纹尖端的J积分值、应力强度因子，根据断裂力学中的K准则、J积分准则判断初始裂纹是否会重新启裂。

Using the perturbation method and Stroh's formula, a nonideal crack, which is mathematically sharp and the opposing crack faces still have a gap in which a stiffless dielectric fills, the two-field problem is reduced to a standard Riemann-Hilbert problem. The internal electric field distribution is obtained by solving a singular integral equation, and then the full field both inside and outside the crack is obtained and the electro-mechanical intensity factors to the first order of accuracy are given.

采用摄动方法对裂尖理想尖锐而裂纹面又具有一定张开的非理想裂纹进行分析，裂隙内含有无刚度的各向同性电介质，利用Stroh公式，将二域问题化为标准的Riemann-Hilbert问题，裂隙内电场分布通过解一个奇异积分方程获得，从而得到裂纹内外的力电全场分布，进而给出一阶精度下的力电强度因子的表达式。

"Bird Man's Diary, Butting on the Love Island", Changsha, China

2008年"鸟人日记，顶在爱情岛"，中国长沙

As long as they were in the service of a family of wizards, their magic would remain dormant.

只要他们一天为家庭服务，他们的法力就潜藏不动。