The influence of different skin types on GSR sampling by tape lifting for SEM analysis

In this study, the change in the amounts the gunshot residues (GSR) collected by the “swab” method from shooter's right hand was analyzed using Scanning Electron Microscope‐Energy Dispersive Spectroscopy (SEM‐EDS) to test dependency on various conditions (such as skin color of the shooter, various physical properties, hair density of hands, size of the hands, sweaty or creamy (oiliness) hands). As a result of the analysis, there was no significant difference in the amount of GSR according to skin color, however, there was a change in the amount of GSR depending on the physical characteristics of the shooter. These results thought to have practical benefits for the experts performing GSR analysis using the swab technique to assess the incidence.     

扫描电镜/X射线能谱仪/X射线波谱仪组合检测射击残留物

在司法物证检验中,通常采用扫描电镜/X射线能谱仪自动检测枪击案件中的射击残留物。但在检出的可疑颗粒物中,经常遇到硫(S)、锑(Sb)元素含量偏低的情况,用X射线能谱仪很难认定该颗粒物就是射击残留物。本文采用了扫描电镜/X射线能谱仪/X射线波谱仪组合方法,能检测出射击残留物中的S和Sb元素,弥补了X射线能谱仪的不足。这种组合形式,能够在微量物证检验工作中发挥很好的作用。     

纳米Sn粒子的制备及其作润滑油添加剂的摩擦学性能研究

用化学还原法制备了表面经油酸修饰的纳米Sn粒子,并在透射电镜(TEM)下观测到所制备的纳米Sn粒子呈球形、平均粒径为20 nm。在MSR-10D四球摩擦磨损试验机上考察了纳米Sn粒子作为CF-4 15W/40润滑油添加剂的摩擦学性能,并在扫描电子显微镜(SEM)和能谱分析仪(EDS)上对钢球磨斑表面进行了形貌观测和表层成分分析。试验结果表明,纳米Sn粒子作为润滑油添加剂具有一定的减摩性能和较好的抗磨性能,当所添加的体积分数仅为0.1%时,添加纳米Sn粒子润滑油的摩擦力比基础油降低了16.64%,其磨斑直径比基础油减小了38.4%。分析认为,纳米Sn粒子通过隔离摩擦表面而改善了润滑油的减摩抗磨性能。     

Automatic wear‐particle classification using neural networks

Although the study of wear debris can yield much information on the wear processes operating in machinery, the method has not been widely applied in industry. The main reason is that the technique is currently time consuming and costly due to the lack of automatic wear particle analysis and identification techniques. In this paper, six common types of metallic wear particles have been investigated by studying three‐dimensional images obtained from laser scanning confocal microscopy. Using selected numerical parameters, which can characterise boundary morphology and surface topology of the wear particles, two neural network systems, i.e., a fuzzy Kohonen neural network and a multi‐layer perceptron with backpropagation learning rule, have been trained to classify the wear particles. The study has shown that neural networks have the potential for dealing with classification tasks and can perform wear‐particle classification satisfactorily. This revised version was published online in June 2006 with corrections to the Cover Date.     

Total quality control for automotive raw foundry brake disks

In this paper, a solution for the automatic raw foundry brake disk dimensional characterisation and visual inspection for the automotive industry is presented. Three different computer vision techniques are used: a calibrated 3D structured-light vision technique, for dimensional characterisation and inspection; a 3D uncalibrated structured-light vision technique for local fault detection; and a common 2D-vision technique for a further local fault recognition. A new and fully automated 3D-calibration procedure for piece dimensional characterisation is also described. The whole system is an accurately synchronised blending of mechanics, automation, computer vision and robotics. Results from industrial implementation are presented.     

A method for measuring the dimensional changes of tissues prepared for scanning electron microscopy

A new method is presented for determining the dimensional changes which can occur during the fixation, dehydration and drying of tissue specimens prepared for examination by the scanning electron microscope (SEM). Photomicrographs of a random array of markers (fluorescent microspheres 9–12 μm diameter, encapsulated in dabs of cyanoacrylate adhesive) on the surface of specimens are obtained with the aid of an optical microscope equipped for fluorescent microscopy. One marker, which is common to each pair of photomicrographs representing the wet and processed conditions of the specimen, is selected from the array of markers. The tracings which depict the outline of the dabs and the location of the microspheres, for the wet and processed specimens are combined into a single composite with the one superimposed marker representing the origin of a set of mutually-perpendicular axes. A newly developed computer programme acquires the coordinates of the marker points, optimizes the alignment of the marker points and computes the proportional dimensional changes in two mutually-perpendicular directions, as well as along the direct path between the common marker and the remaining markers.     

扫描电子显微镜/能谱仪在刑事案件技术检验中的应用

通过几起典型的案例,介绍了扫描电子显微镜/能谱仪在盗窃、枪击、爆炸以及交通肇事等案件中的应用。扫描电子显微镜/能谱仪由于放大倍率、分辨率、灵敏度高,同时具有快速、简便、检材用量少且不破坏检材等特点,是刑事案件技术检验的重要工具。利用扫描电子显微镜/能谱仪检验微量物证的显微形貌、无机元素成分及各元素成分的相对含量、X-射线面的分布,可以达到定性定量分析的目的,揭露和证实犯罪事实真相。     

超声电沉积镍/纳米碳化硅复合镀层组织结构研究

采用超声电沉积方法在20钢基体上制备了镍／纳米碳化硅的复合镀层。通过扫描电镜(SEM)观察了镀层的表面形貌和显微组织，用能谱仪(EDS)对镀层中特定区域进行了显微组织成分分析，使用X射线衍射仪检测了镀层的微观结构。结果表明：通过合适的超声电沉积工艺，得到的镀层中SiC纳米粒子含量较高，且分散均匀，没有出现团聚现象；同时镀层中的镍晶粒得到了细化，取向也由择尤取向趋于随机取向。     

The use of scanning electron microscopy to quantify the burden of particles released from clean-room wiping materials

A procedure is described for the detection and direct enumeration of the number of particles that can potentially be released from wiping materials. The technique involves the use of a scanning electron microscope (SEM) to count the particles from a wiper, first by releasing them in deionized water and then filtering the entirety of the liquid through a submicron membrane filter. To obtain an accurate count, the filtration must produce a normal distribution of particles on the filter, and hence the details of the filtering technique must be performed in a very precise manner. The counting of the particles on the filter is accomplished by scanning a statistically representative number of fields and averaging the number of particles per field. The results can then be checked for statistical precision and accuracy. Our criterion for successful measurement was ± 10% accuracy at a 95% confidence level. We believe that the SEM method described in this article is sensitive enough to quantify very low levels of total particle burden without succumbing to the variability and limitations encountered with other enumeration techniques. Typically, this technique enables the accurate counting of particles of all shapes from below 0.1 μm to hundreds of micrometers. In addition, the SEM technique allows for morphologic identification of particles as well as chemical identification if an energy-dispersive x-ray system (EDS) is employed.     

SiCp/Cu复合材料的显微组织和力学性能

采用非均相沉淀包裹法制得铜包SiC复合粉体,利用热压烧结工艺制备了含有体积分数为20%～65%SiC颗粒的SiCp/Cu复合材料.用X射线衍射仪、扫描电镜、能谱分析等测试方法对试样进行了成分和微观形貌分析.结果表明:包裹法制得的SiCp/Cu复合材料中基体铜形成连续的结构,SiC分散较均匀;随着SiC含量的增加,试样孔隙率提高,抗弯强度下降;而硬度则先增后降,并在SiC体积分数为35%时出现最大值;所有试样均表现为脆性断裂.     

机器人多指手预抓取模式聚类分析

提出一种基于计算机视觉的,以及改进的模糊C均值聚类算法的机器人多指手预抓取模式分类方法.根据人手抓取分类学,将抓取手势分为13类.选取若干具有代表性的不规则形状物体,先经视觉系统采集物体图像,然后运用数字图像处理方法提取物体的姿态、大小、形状和表面粗糙度等特征,最后利用改进后的模糊C均值聚类算法对待抓取物体进行聚类分析.实验结果表明:对比人类抓取策略,该方法具有理想的预抓取模式分类效果.     

Correlating auger electron spectroscopy with scanning electron microscopy-energy dispersive spectroscopy for the analysis of respirable particles

A method has been developed to characterize large populations of individual respirable particles. With the use of custom data collection and data correlation computer software, the same set of particles can be analyzed in multiple instruments. The method is demonstrated by the analysis of a sample of hard-metal particles. A series of particles are analyzed by Auger electron spectroscopy, and then the same particles are analyzed by scanning electron microscopy-energy dispersive spectroscopy.     

电泳-电沉积制备纳米Al_2O_3增强镍基复合镀层中纳米颗粒的分布状态

采用电泳-电沉积技术制备了纳米Al2O3增强镍基复合镀层,并采用扫描电镜及其附带能谱仪分析了镀层中纳米颗粒的分布状态,运用正交试验法研究了电泳液中纳米颗粒含量、电泳沉积电压、电泳沉积时间以及电沉积阴极电流密度等工艺参数对复合镀层中纳米颗粒分布均匀性的影响.结果表明:电泳液中纳米颗粒含量及电沉积阴极电流密度是影响镀层中纳米颗粒分布均匀性的主要因素,而电泳沉积电压和电泳沉积时间的影响相对较小;在电泳液中A12O3纳米颗粒含量为8 g·L-1、电沉积阴极电流密度为0.5 A·dm-2时,可制得纳米颗粒均匀分布的纳米复合镀层.     

[可靠性建模及试验技术]重型机床液压元件油液污染退化量分布剖面可靠性建模

针对重型机床液压系统故障频繁且多与油液中的固态颗粒污染物相关的问题，进行了油液污染趋势变化试验。通过时域分析获得了油样颗粒数的有量纲和量纲一参数，通过Q-Q图和K-S检验分析有量纲参数，污染颗粒数是退化量服从正态分布的退化数据。进行了油液污染与环境相关性分析试验，采用相关系数法分析得到，颗粒数变化量与一定范围内的温度、流量、压力的相关性小；将液压元件分为管路、阀、过滤器三类，用直径5 μm左右的颗粒和直径大于15 μm的颗粒分别研究管路及阀件的堵塞和磨损情况，以过滤器过滤精度大小的颗粒研究过滤器的堵塞情况，设定ISO4406标准20/17级对应的颗粒数为阈值，利用退化量分布建立了液压元件单一故障模式的可靠性模型；利用竞争失效模型将上述模型融合为多故障模式下的可靠性模型。     

SEM-EDS technique employed in evaluating the aggregation behaviors of amphiphilic ABC-type triblock copolymers in mixed solvents with tuned polarities

In this paper, a scanning electron microscopy‐energy dispersive spectroscopy (SEM‐EDS) technique has been developed for evaluating the aggregation structure of amphiphilic fluorinated ABC‐type triblock copolymers MeOPEO₁₆‐PSt₂₂₀‐PFHEA₂₂ in mixed solvents with different polarities. The polarities of mixed solvents can be tuned by changing volume ratios of toluene, anhydrous ethanol, and distilled water, which leads to the changes in morphology and size of self‐assembled colloidal particles of the copolymers in the system. The aggregation behaviors of the copolymers are revealed by SEM, transmission electron microscopy (TEM), and corresponding SEM‐EDS techniques. The variations in concentrations of O and F elements over the thickness of copolymers particles give direct evidence for a better understanding of the arrangement of each block segment of copolymers in solution. And the technique can also help to explain the aggregation structure of micro‐ or nanomaterial with shell‐core structure. Microsc. Res. Tech., 2011. © 2011 Wiley Periodicals, Inc.     

Wear Behavior of Dual Particle Size (DPS) Zircon Sand Reinforced Aluminum Alloy

The present investigation aims to find the combined effect of coarse and fine size particle reinforcement of zircon sand in aluminum alloy LM13 on the wear behavior. The composites are fabricated by varying the reinforcement of fine and coarse size zircon sand particles and compared with the single size reinforcement. Coarse and fine particle zircon sand of 106?C125 and 20?C32-??m size, respectively, are used in this study. The wear test was carried out on pin-on-disc machine. Microhardness measurement was done for developed composites. Wear track and debris are analyzed by SEM to study the wear mechanism. Line profile and EDS analysis is also done to validate the microstructural results. Study reveals that a combination of 3?% fine and 12?% coarse particle reinforced composite exhibits better wear resistance while 3?% coarse and 12?% fine particle reinforcement decreases the wear resistance. It is also observed that zircon sand particles provide effective nucleation site for the eutectic silicon. Microstructural examination shows globular and finely distributed eutectic silicon in the vicinity of the reinforced particles.     

Geometric Design-based Dimensional Synthesis of a Novel Metamorphic Multi-fingered Hand with Maximal Workspace

Current research on robotic dexterous hands mainly focuses on designing new finger and palm structures,as well as developing smarter control algorithms.Although the dimensional synthesis of dexterous hands with traditional rigid palms has been carried out,research on the dimensional synthesis of dexterous hands with metamorphic palms remains insufficient.This study investigated the dimensional synthesis of a palm of a novel metamorphic multi-fingered hand,and explored the geometric design for maximizing the precision manipulation workspace.Different indexes were used to value the workspace of the metamorphic hand,and the best proportions between the five links of the palm to obtain the optimal workspace of the metamorphic hand were explored.Based on the fixed total length of the palm member,four nondimensional design parameters that determine the size of the palm were introduced;through the discretization method,the influence of the four design parameters on the workspace of the metamor-phic hand with full-actuated fingers and under-actuated fingers was analyzed.Based on the analysis of the metamor-phic multi-fingered hand,the symmetrical structure of the palm was designed,resulting in the largest workspace of the multi-fingered hand,and proved that the metamorphic palm has a massive upgrade for the workspace of underactuated fingers.This research contributed to the dimensional synthesis of metamorphic dexterous hands,with practical significance for the design and optimization of novel metamorphic hands.     

Is Scanning Electron Microscopy/Energy Dispersive X‐ray Spectrometry (SEM/EDS) Quantitative?

Scanning electron microscopy/energy dispersive X‐ray spectrometry (SEM/EDS) is a widely applied elemental microanalysis method capable of identifying and quantifying all elements in the periodic table except H, He, and Li. By following the “k‐ratio” (unknown/standard) measurement protocol development for electron‐excited wavelength dispersive spectrometry (WDS), SEM/EDS can achieve accuracy and precision equivalent to WDS and at substantially lower electron dose, even when severe X‐ray peak overlaps occur, provided sufficient counts are recorded. Achieving this level of performance is now much more practical with the advent of the high‐throughput silicon drift detector energy dispersive X‐ray spectrometer (SDD‐EDS). However, three measurement issues continue to diminish the impact of SEM/EDS: (1) In the qualitative analysis (i.e., element identification) that must precede quantitative analysis, at least some current and many legacy software systems are vulnerable to occasional misidentification of major constituent peaks, with the frequency of misidentifications rising significantly for minor and trace constituents. (2) The use of standardless analysis, which is subject to much broader systematic errors, leads to quantitative results that, while useful, do not have sufficient accuracy to solve critical problems, e.g. determining the formula of a compound. (3) EDS spectrometers have such a large volume of acceptance that apparently credible spectra can be obtained from specimens with complex topography that introduce uncontrolled geometric factors that modify X‐ray generation and propagation, resulting in very large systematic errors, often a factor of ten or more. SCANNING 35: 141‐168, 2013. ¹ Published 2012 Wiley Periodicals, Inc.     

基于计算机视觉的干枣在线分级

研究了基于计算机视觉的干枣在线分级,通过计算机视觉技术获取干枣的图像,对该图像进行阈值分割等处理,确定干枣的检测方向,进一步对干枣的尺寸、颜色、缺陷等进行快速精确的分类。试验表明,该方法检测速度快,正确率高,适用范围宽,能够满足农产品加工过程中计算机视觉水果分级技术的要求。