The Use of Acoustic Emission Intensity Analysis for the Assessment of Cover Crack Growth in Corroded Concrete Structures

In this paper, acoustic emission (AE) intensity analysis was utilized to assess the concrete cover cracking due to steel corrosion in reinforced concrete structures. A total of 30 reinforced concrete prism samples were tested under an accelerated corrosion test coupled with continuous AE monitoring using attached AE sensors. The samples were cast with three concrete cover thicknesses (20, 30 and 40 mm) around steel bars and were exposed to five percentages of steel mass loss: 1, 2, 3, 4, and 5 %. The cover cracking was monitored daily by visual inspection to detect and measure crack widths. Different AE signal parameters were continuously recorded during the tests, including number of hits, signal strength, energy, and amplitude. The acquired AE events were subjected to an intensity analysis of signal strength to estimate historic index (H (t)) and severity (\(S_r)\). In addition, a b value analysis was conducted on all AE data and the results were compared to those obtained from the intensity analysis. The results showed that increasing the cover thickness had no significant impact on AE parameters (number of hits, cumulative signal strength, cumulative energy, amplitude, H (t), and \(S_{r})\) at similar values of crack growth. Nonetheless, varying the cover thickness from 20 to 40 mm resulted in lower crack widths and slightly higher b values at the same levels of steel mass loss. It was also found that both H (t) and \(S_r\) showed a more evident correlation with the values of crack growth than did b values, regardless of cover thickness or percentage of steel mass loss. Finally, an intensity classification chart was developed to quantify the cover crack growth based on the values of H (t) and \(S_{r}\).     

X-Y digital autocollimator with 0.001″ resolution

A device and elements of the software of an X-Y digital autocollimator for measurement of small angles are described. Results of calibration and test measurements are presented. An analysis of the requirements for ensuring the temperature stability of the environment is given.Translated from Izmeritelnaya Tekhnika, No. 12, pp. 29–32, December, 2004.This revised version was published online in April 2005 with a corrected cover date.     

基于Workbench的二通阀疲劳分析及结构优化设计

目的为了研发设计某型号二通阀,使其正常工作2年内(5000 h)不失效。方法基于Ansys Workbench仿真软件对二通阀阀芯撞击盖板过程进行显式动力学分析和疲劳分析,得到二通阀的薄弱环节,并对关键易损部位进行优化设计和对比分析。结果将最小截面处直径由24.5 mm增至28mm后,在不影响二通阀密封性能的前提下,满足二通阀持续工作5000 h不发生疲劳破损。结论对二通阀进行显式动力学分析后,再以阀芯撞击盖板时的最大应力加载阀芯进行了疲劳分析,使分析结果更为可靠。     

Identification of single bacterial cells in aqueous solution using confocal laser tweezers Raman spectroscopy

We report on a rapid method for reagentless identification and discrimination of single bacterial cells in aqueous solutions using a combination of laser tweezers and confocal Raman spectroscopy (LTRS). The optical trapping enables capturing of individual bacteria in aqueous solution in the focus of the laser beam and levitating the captured cell well off the cover plate, thus maximizing the excitation and collection of Raman scattering from the cell and minimizing the unwanted background from the cover plate and environment. Raman spectral patterns excited by a near-infrared laser beam provide intrinsic molecular information for reagentless analysis of the optically isolated bacterium. In our experiments, six species of bacteria were used to demonstrate the capability of the confocal LTRS in the identification and discrimination between the diverse bacterial species at various growth conditions. We show that synchronized bacterial cells can be well-discriminated among the six species using principal component analyses (PCA). Unsynchronized bacterial cells that are cultured at stationary phases can also be well-discriminated by the PCA, as well as by a hierarchical cluster analysis (HCA) of their Raman spectra. We also show that unsynchronized bacteria selected from random growth phases can be classified with the help of a generalized discriminant analysis (GDA). These findings demonstrate that the LTRS may find valuable applications in rapid sensing of microbial cells in diverse aqueous media.     

Parameter discretization in two-dimensional continuous wavelet transform for fast fringe pattern analysis

The two-dimensional continuous wavelet transform (2D-CWT) technique provides robust processing for digital fringe pattern analysis. To cope with the problem of long computation time, a concept called the cover map is introduced to speed up the 2D-CWT analysis. The cover map is constructed by discretizing the continuous dilation and rotation parameters. The discretized parameters help substantially reduce the processing time without affecting the analysis accuracy. The theories are presented and the validity and effectiveness of the proposed concept are demonstrated by computer simulation and real experiment.     

Retrospective review of experience with using the NUPRA software

The models used in probabilistic risk assessment (PRA) by the nuclear industry are supported by a wide variety of computer software. In fact, prior to the publication of the WASH-1400 in 1974, researchers and practitioners had already initiated the software development process leading to today's advanced and user-friendly PC-based software packages. NUS Corporation initiated its PC code development in the early 1980s. After testing a number of prototypes, a first integrated package supporting all parts of the Level 1 PRA was launched in 1987. This software package, called NUPRA, is an implementation of an approach based on minimal cutset equations and it has been used to install ten PRA studies on a PC. Insights from applications are now used to enhance the current NUPRA package to cover Level 2 and Level 3 analysis needs. In this paper the experience of using the NUPRA software is documented.     

常闭阀罩生产过程质量控制研究

为了解决某公司常闭阀罩生产过程中质量不稳定、生产过程能力低等问题,将质量管理方法应用于常闭阀罩生产的管理过程。利用测量系统分析、过程能力分析、一元线性回归分析等方法进行产品质量的分析,并结合Minitab 软件里面的功能模块,精确计算过程能力指数,生成控制图,根据判定准则,给出判定结论。企业应用实例表明,该公司在实施了质量控制后,过程能力提高,废品率降低,有效地提高了产品质量。     

基于代理模型和改进遗传算法的注塑翘曲优化

提出一种最小化制品翘曲的注塑工艺参数优化集成方法.以空调柜机顶盖注塑制品开发为例,该方法使用Moldflow软件分析制品的翘曲变形,运用田口方法确定与制品翘曲量密切相关的工艺因素,然后采用响应曲面法(RSM)和改进的精英保留自适应遗传算法(EAGA)相结合的方法,建立主要影响工艺参数与制品翘曲量之间的关系模型,通过对模型寻优以实现对制品翘曲的优化.该方法的适用性在制品的实际生产中得到了验证.     

分形艺术视角下的德罗斯特效应研究

目的 研究德罗斯特效应中的分形艺术原理,掌握德罗斯特效应图像的设计制作方法。方法 从分析分形艺术原理入手,通过数理原型、构成法则和美学特征3个方面,在分形艺术视角下展开对德罗斯特效应的全面研究,总结德罗斯特效应图像“回”形范式与“海螺”形范式的共通性与区别,并应用Photoshop和GIMP软件制作范式图像。结论 德罗斯特效应图像的两种范式都具备相似的“镜中镜”特征或者“三维螺旋线”数理原型特征;在构成上,其自相似性和可无限缩放的特性属于分形艺术的范畴;图像的视觉特效给人们带来了新的情感体验与审美感受,并有助于提高人们的平面设计水平。     

High molecular weight polyethylene nanospheres: synthesis physical and mechanical properties

The high molecular weight (MW) polyethylene (PE) particles of particle size varied from macro to micron to nanometer were synthesized by Grignard reagent. The microscopy analysis (scanning electron microscope, SEM; transmission electron microscope, TEM; and atomic force microscope, AFM) shows the spherical shape of PE particles. The effects of particle size, varies from macro to nanometer scale on crystal structure, crystallinity (chic), glass transition temperature (Tg), melting temperature (Tm), surface roughness and mechanical properties were studied. Differential scanning calorimetry (DSC) experiments show that the nanoparticles of PE are highly crystalline (chic approximately equal 72%). The crystal length of PE nanoparticles is found to be approximately 14 A. Although the Gibbs-Thomson equation is explained the depression of melting temperature (DeltaTm) by 5 degrees C, the impervious results of Tg are still not fully understood. The low roughness value (2 A) proves the presence of "atomic-scale-chain" folding at the surface of PE nanoparticles. A novel protocol is developed, and the elastic modulus of individual nanospherical PE particles is computed from 'force-distance' mapping curves of AFM. Hemispherical tungsten (W) tip was fabricated from focused ion beam and used as an indenter to measure the mechanical properties. It is found that the nano sized PE particles have higher elastic modulus (E = 1.2-1.4 GPa) compared to the bulk or macro sized PE (E = 0.6-0.7 GPa). The results corroborate the robustness of our experiments, since, the analogous results for macro sized particles match well with the literature.     

摩托车变速箱端盖辐射噪声仿真分析

应用有限元软件Nastran与边界元软件SYSNOISE对摩托车变速箱端盖的辐射噪声进行了仿真计算分析研究,预测了外部声场辐射噪声声压,分析了声场声压与结构模态频率之间的关系,确定了辐射噪声的关键区域和频带,结果说明FEM/BEM方法是预测辐射噪声的有效方法,分析结果为我们下一步声学优化打下了基础。     

时代记忆:《人民画报》(1950—2015年)封面图像叙事设计

目的《人民画报》以图像的形式记录了中国时代发展的脉络,其封面图像作为时代记忆集成式的视觉语言,起到了传播时代烙印的重要作用。通过人民画报的视觉图像唤起时代的记忆,提升该类型刊物的图像叙事能力和视觉形象,扩大时代记忆图像的传播。方法 收集了《人民画报》1950—2015年共计810幅封面图像作为视觉分析样本,将《人民画报》划为四个阶段,即第一阶段（1950—1965年）继往开来,传播力量;第二阶段（1966—1976年）记录历史,唤醒革命;第三阶段（1977—1998年）改革创新,发展文体;第四阶段（1999—2015年）大国风采,迈向未来。通过图像分析法和文献研究法对摄影图像元素、字体版式与插图布局等维度进行分析。结论 分析得出,社会发展的进程决定了《人民画报》本身的视觉叙事的内容;字体排版方式辅助读者更获取信息,提升读者阅读信息效率;技术的提高促进图像叙事的风格转变,提升叙事空间维度。     

Automation of a surface sampling probe/electrospray mass spectrometry system

An image analysis automation concept and the associated software (HandsFree TLC/MS) were developed to control the surface sampling probe-to-surface distance during operation of a surface sampling electrospray system. This automation system enables both "hands-free" formation of the liquid microjunction used to sample material from the surface and hands-free reoptimization of the microjunction thickness during a surface scan to achieve a fully automated surface sampling system. The image analysis concept and the practical implementation of the monitoring and automated adjustment of the sampling probe-to-surface distance (i.e., liquid microjunction thickness) are presented. The added capabilities for the preexisting surface sampling electrospray system afforded through this software control are illustrated by an example of automated scanning of multiple development lanes on a reversed-phase C8 TLC plate and by imaging inked lettering on a paper surface. The post data acquisition processing and data display aspects of the software package are also discussed.     

涡旋压缩机模态试验与有限元分析

利用LMS公司TEST Lab 5 A模态试验系统,采用锤击法,对某型涡旋压缩机的曲轴进行试验,然后进行模态分析,获得前3阶模态参数;通过有限元分析软件ANSYS对曲轴进行同样工况下的模态计算,对比试验模态参数与计算模态参数,二者误差在允许范围之内;再采用ANSYS对涡旋压缩机其他主要零部件进行模态计算,获得前6阶模态参数,并对上顶盖、壳体和装配体的各阶振型进行分析,为涡旋压缩机主要零部件的动力学分析和结构设计改进提供依据。     

薄圆柱体高频感应温度场的测量和有限元模拟

本文利用自制的NiCr-NiAl热电偶精确地测量了薄圆柱工件端面高频感应温度场的分布;应用有限元分析软件ANSYS/Thermal对高频感应加热过程的温度场进行了模拟.热电偶测量的数据直观可信,但测取工件温度场分布费时费力;有限元分析则可较为快速获知工件各处的温度,弥补了实验工作的不足.本文研究结果显示,两种方法得出的结果具有可比性,能够相互参照.     

Waveguide analysis of organic light-emitting diodes fabricated on surfaces with wavelength-scale periodic gratings

Numerical techniques for the analysis of multilayer waveguide structures were used to study the modes that exist in organic light-emitting diode (OLED) devices. The analysis revealed that waveguide modes of the OLED structure could be grouped, according to the behavior of modal-field profiles in the air cover and the glass substrate, into one of four different "families": (i) bound mode, (ii) semibound modes, (iii) leaky modes, and (iv) nonphysical modes. Four different OLED samples were fabricated on glass substrates on which photoresist gratings had been previously formed. The theory was used to compute the angles at which light from these devices should exit into the air. Theory and data agreed well for the semibound modes for all samples; however, they did not agree so well for the leaky modes. Further investigation revealed that better agreement between theory and data could be obtained with these modes being analyzed as Fabry-Perot cavity modes. The theoretical relation between leaky waveguide modes and Fabry-Perot cavity modes is discussed.     

湘东地区的民间传统竹木制蒸炊器具设计研究

目的 分析湖湘饮食特色中“蒸炊”的竹木制器物的特点,探寻其设计理念,扩展认识湖湘文化的新视角。方法 对株洲、浏阳、长沙等湘东地区的民间蒸炊器具进行调查,并测得其主要尺寸,运用功能分析法把典型器具分为甑、蒸盖、箅、舀水器等。结合当地的饮食习惯和传统文化,运用形式分析、逻辑推理等方法,对用材、形式、功能、结构等进行具体分析。结论 湘东地区民间传统蒸炊器具具有世俗性、科学性、艺术性等特点,其设计遵循“取材因地制宜、制器功能至上、造型简朴规整”的造物规律。     

Object-oriented concept analysis for software modularisation

Modularity is one of the most important principles in software engineering and a necessity for every practical software. Since the design space of software is generally quite large, it is valuable to provide automatic means to help modularising it. An automatic technique for software modularisation using object-oriented concept analysis (OOCA) is proposed. The proposed technique is strongly inspired by the success of reverse engineering techniques based on formal concept analysis (FCA). However, our experience shows that FCA-based techniques generally result in fine-grained modules and, thus, may be inadequate for modularising large-scale designs. To overcome this weakness, the authors employ OOCA, a recent proposal for concept formulations. OOCA enables to provide coarse concepts as module candidates while keeping the advantage of FCA techniques. To the best of the authors' knowledge, it is the first work to apply OOCA in software engineering research. To illustrate the potential of the approach, the authors perform a software modularisation case study on a real insurance software design with comparison.     

基于塑性破坏的承压水基坑突涌计算模型研究

针对软土地区不透水隔水层承压水基坑,从坑底土产生塑性变形破坏的力学机理出发,建立了基于塑性破坏的承压水基坑突涌计算模型,提出了屈服应力比概念和基坑突涌判断标准。用考证实例将模型计算结果与离心试验结果、现场观察结果以及压力平衡理论计算结果进行了比较。结果表明:模型计算结果与离心模型试验结果和现场观察结果比较吻合;而压力平衡理论判断结果与离心模型试验结果和现场观察结果有较大出入。因此,对于软土地区坑底存在不透水隔水层的承压水基坑,采用突涌塑性破坏模型分析基坑抗突涌稳定性是合理可靠的。