人工神经网络技术在服装上的应用

介绍了人工神经网络的概念及基本特点，总结了其在服装中的应用和实现方法，指出神经网络技术在服装方面广泛的应用前景。     

超声表面波探伤在轴承检测中的应用

对成品轴承检测时的超声表面波探伤进行了技术分析,阐述了超声表面波的探伤原理,并分析了其应用的可能性。通过试验表明,在成品轴承不拆卸的情况下,超声表面波技术可有效检测轴承零件的表面缺陷,并且对轴承的使用不会产生影响,降低了成品轴承在质量抽查、复查过程中存在的困难,为关键部位轴承的生产、使用、维护及保养提供安全可靠的实用检测手段。     

论V型柴油机整铸机体的生产工艺

V型柴油机整铸机体在中高速柴油机领域的应用较为广泛,本文从16RK270型柴油机整铸机体的造型和铁液熔炼两方面入手,对其铸造工艺进行了论述,并在实际生产中,成功的铸造出该产品,完全达到了设计要求。     

904L不锈钢丝疲劳性能差异分析

采用扫描电镜观察等方法，比较不同批号的美国进口９０４Ｌ不锈钢丝断口特征、表面形貌，分析其产生疲劳性能划原因。结果表明，表面缺陷与疲劳裂纺源的形成密切相关，而内部材质对裂纹的扩展起重要作用。     

螺旋埋弧焊钢管内焊缝自动跟踪原理的研究

螺旋埋弧焊钢管内焊缝自动跟踪问题，是国内外以来没有很好解决的一大难题。本文对实现自动跟踪的原理进行了比较详尽的分析和研究，提出了焊缝背面两侧侧温度呈驼峰形分布的全新理论。作者认为，以往人们使用扔内焊头手动跟踪都是遵循驼峰理论来实现的。     

抽油杆扳手方缺陷应力集中系数和容限

针对抽油杆扳手方部位经常出现引发断裂的各种缺陷的情况，建立了横向凹槽、平面凹坑和边棱凹坑三组有代表性的缺陷模型，利用平面模型有限元法计算结果及受拉伸无限体和半无限体旋转椭球面空洞和凹坑应力集中系数，求得近、远边界影响修正系数以及三组不同缺陷模型应力集中系数近似表达式。用三维趋势面图描述了这些应力集中系数的变化规律，求得各组缺陷容限方程，绘制了典型的容限图，为带缺陷抽油杆的修复使用和判废提供了理论依据。     

UNIX操作系统安全分析

UNIX操作系统的安全性已经成为受人关注的问题。本文从逻辑安全角度出发,针对普通用户、超级用户和源代码编制者,主要就BSD4 UNIX讨论各种可能的安全违例,并揭示一些现有版本中存在的漏洞。     

ANALYSIS OF CRACK INITIATION AND PROPAGATION IN FRETTING FATIGUE: THE EFFECTIVE INITIAL FLAW SIZE METHODOLOGY

Abstract— A number of fretting fatigue tests were carried out on CMV steel and INCO 718 alloys under closely controlled experimental conditions. A fracture mechanics-based lifing model was developed and the Paris Law employed to predict fatigue lives under a range of experimental conditions. An effective initial flaw size was used to describe initiation and early propagation of cracks. This approach was found to give good predictions of fatigue life of specimens for different values of bulk stress under the same fretting load.     

混凝土工程外观缺陷处理方法

对于混凝土工程,不仅要关注混凝土强度,而且还要求其外观质量。本文从实践操作经验出发,就如何保证混凝土质量问题提出了自己的看法。     

A multiscale flaw detection algorithm based on XFEM

We present a novel multiscale algorithm for nondestructive detection of multiple flaws in structures, within an inverse problem type setting. The key idea is to apply a two‐step optimization scheme, where first rough flaw locations are quickly determined, and then, fine tuning is applied in these localized subdomains to obtain global convergence to the true flaws. The two‐step framework combines the strengths of heuristic and gradient‐based optimization methods. The first phase employs a discrete‐type optimization in which the optimizer is limited to specific flaw locations and shapes, thus converting a continuous optimization problem in the entire domain into a coarse discrete optimization problem with limited number of choices. To this end, we develop a special algorithm called discrete artificial bee colony. The second phase employs a gradient‐based optimization of the Broyden–Fletcher–Goldfarb–Shanno type on local well‐defined and bounded subdomains determined in the previous phase. A semi‐analytical approach is developed to compute the stiffness derivative associated with the evaluation of objective function gradients. The eXtended FEM (XFEM), with both circular and elliptical void enrichment functions, is used to solve the forward problem and alleviate the costly remeshing of every candidate flaw, in both optimization steps. The multiscale algorithm is tested on several benchmark examples to identify various numbers and types of flaws with arbitrary shapes and sizes (e.g., cracks, voids, and their combination), without knowing the number of flaws beforehand. We study the size effect of the pseudo grids in the first optimization step and consider the effect of modeling error and measurement noise. The results are compared with the previous work that employed a single continuous optimization scheme (XFEM–genetic algorithm and XFEM–artificial bee colony methods). We illustrate that the proposed methodology is robust, yields accurate flaw detection results, and in particular leads to significant improvements in convergence rates compared with the previous work. Copyright © 2014 John Wiley & Sons, Ltd.