拉拔类检测仪器及检测方法研究

拉拔类仪器主要用于建筑行业的各项参数检测,其准确度关乎建筑行业的安全性,更准确的校准该类仪器是计量部门的重要任务,本文主要介绍拉拔类检测仪器的结构和工作原理,以及探讨各种拉拔类检测仪器的校准方法,并对校准方法进行总结。     

Reliability and maintenance strategy for systems with aging‐dependent components

An innovative approach is presented for the reliability analysis of aging multistate systems that considers the subsystems and their components' dependency. A reliability function is determined for an aging series system with the component dependency following the local load‐sharing rule, and a reliability function is determined for an aging “m out of n” system with the component dependency following the equal load‐sharing rule. Linking the results of those load‐sharing models, a mixed‐dependency model for multistate “m out of l”‐series systems is constructed by assuming the dependence between subsystems connected in series under the local load‐sharing rule and the dependence between their components under the equal load‐sharing rule. As a special case, the reliability of this system, modeled using piecewise exponential reliability functions, is considered, and the results are applied to characterize shipyard rope elevator reliability. Finally, the maintenance of this elevator as a repairable multistate system is analyzed with the time of renovation ignored.     

Characterization of the material elongation in the deep drawing of paperboard

In this paper, deep‐drawn paperboard cups are characterized in terms of their elongation along the cup wall. For this purpose, a method for the non‐destructive determination of the elongation was developed and tested. Using the presented method, a parameter study of the process parameters blank holder force, forming temperature, material moisture content, drawing velocity, and clearance ratio was performed. The influence of the process parameters on the cup wall elongation was determined by statistical design of experiments. Using the determined relationships between the process parameters, it was possible to achieve a shape‐specific characterization of the elongation along the cup wall. The parameter study showed a significant influence of the blank holder force, the forming temperature, and the material moisture content to the elongation along the cup wall.     

肖像照片漫画风格化方法

为了解决已有方法不能自动生成反映五官特征且具有写实漫画风格的线条画的问题,基于数据驱动和滤波的混合方法,提出一种漫画风格肖像线条画自动生成的方法.将五官和头发分为2部分,基于数据驱动的方法合成五官,使用非数据驱动的方法生成头发.在已有的特征点基础上,从数据库中匹配合适的五官数据生成五官图片.对于头发的处理,使用Canny边缘检测、图像二值化、自适应阈值二值化和XDoG算子4种不同处理方法生成头发线条域;为了更接近绘画效果,使用不同的绘画纹理与头发线条域进行叠加,生成具有不同纹理、不同风格的头发.整合五官图片和头发图片,最终生成肖像的漫画风格线条画.从互联网上获取图片构建数据集进行实验,采用不同方法生成不同风格的图片,并请专业和非专人士分别对图像质量的高低、人物特征的把握准确程度和整体审美效果3个方面打分进行评估.结果表明,所提方法能够实时地处理发生偏侧的人脸图片,与其他方法相比,该方法能生成的图片是写实漫画风格而非卡通风格或素描风格,在生成漫画风格夸张五官的同时处理结构复杂的头发.     

函数曲线生成器的设计

本文主要研究了通用函数方程的曲线绘制过程。根据用户输入的函数表达式,使用VC++编程语言对输入的字符串进行分析,并绘制出相对应的函数曲线。该研究包括函数方程式的解析和逆波兰式求值、规定区域内函数曲线初始值和初始方向的确定,以及函数曲线的逐点绘制过程。根据MFC图像绘制方法,本文还研究了内存DC缓冲技术,建立基于Bitmap的内存兼容DC,以高效地完成函数图像的平移和缩放操作方法。本研究已实现多项式函数、常用数学函数以及数学函数的复杂嵌套形式的绘制。当用户输入出现错误时,能够智能地提示错误位置。本研究对数学教学和函数模型研究具有深刻的意义。     

基于等高替换和随机反向的粒子群算法

针对标准粒子群优化算法不易跳出局部寻优、搜索精度低等缺陷,提出了等高随机替换策略,运用简化粒子群算法进行更新,加快了粒子寻优能力;并且对适应值最差的一部分粒子,采用了最优随机反方向搜索策略,保证了算法的全局搜索能力。对6个单模和多模测试函数进行仿真实验,结果表明了改进的算法能很好地保持粒子多样性,全局搜索能力强,拥有更好的的收敛速度和寻优精度。     

《墨子》的几何学与图学成就及其科学价值

《墨子》是我国古代最早论述图学知识、图学思想的科技史著作。《墨子》一书 中的论述与记载表明：图形、图样与文字、数字一样,在人类的社会进步和科技发展过程中起 着不可替代的作用。对《墨子》的研究,特别是对其图学基本概念与基本理论的探讨及其历史 地位;仍是一个有待深入和系统阐明的课题。本文通过考察《墨子》对有关图学理论研究的尝 试,探讨中国古代科学技术中的图学实践与图学知识的成果,以及这些图学成果所体现的中国 图学传统与科学探索精神。     

PTT长丝瞬时拉伸回弹性能研究

在相同条件下对比研究了PET ,PTT和PBT 3种芳香族聚酯长丝的瞬时拉伸回弹性能 ,分析了测定条件对PTT长丝瞬时拉伸回弹性能的影响 ,并初步讨论了 3种芳香族聚酯长丝的瞬时拉伸回弹机理。结果表明 ,PTT长丝的瞬时拉伸回弹性能明显优于PBT长丝 ,更优于PET长丝 ,PTT长丝在低伸长率和高伸长率下均具有优异的瞬时拉伸回弹性能 ;测定PTT长丝瞬时拉伸回弹率时 ,建议采用 0 .5cN/tex的预张力 ,5 0 0mm/min的拉伸速率和 2 0 %的定伸长率等条件     

Morphology and barrier mechanism of biaxially oriented poly(ethylene terephthalate)/poly(ethylene 2,6‐naphthalate) blends

To improve the barrier properties of poly(ethylene terephthalate) (PET), PET/poly(ethylene 2,6‐naphthalate) (PEN) blends with different concentrations of PEN were prepared and were then processed into biaxially oriented PET/PEN films. The air permeability of bioriented films of pure PET, pure PEN, and PET/PEN blends were tested by the differential pressure method. The morphology of the blends was studied by scanning electron microscopy (SEM) observation of the impact fracture surfaces of extruded PET/PEN samples, and the morphology of the films was also investigated by SEM. The results of the study indicated that PEN could effectively improve the barrier properties of PET, and the barrier properties of the PET/PEN blends improved with increasing PEN concentration. When the PEN concentration was equal to or less than 30%, as in this study, the PET/PEN blends were phase‐separated; that is, PET formed the continuous phase, whereas PEN formed a dispersed phase of particles, and the interface was firmly integrated because of transesterification. After the PET/PEN blends were bioriented, the PET matrix contained a PEN microstructure consisting of parallel and extended, separate layers. This multilayer microstructure was characterized by microcontinuity, which resulted in improved barrier properties because air permeation was delayed as the air had to detour around the PEN layer structure. At a constant PEN concentration, the more extended the PEN layers were, the better the barrier properties were of the PET/PEN blends. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1309–1316, 2006