基于机器视觉的锭坯轮廓在线检测系统研究

喷射成形是一种基于快速凝固技术的高温合金、高性能材料制备工艺,对喷射成形过程中沉积锭坯的轮廓及其形状特征进行实时、准确地检测是实现喷射成形工艺稳定性控制的关键。基于机器视觉技术研究了喷射成形锭坯轮廓在线检测方法,设计了视觉检测系统结构,对喷射成形生产环境下的锭坯轮廓图像处理算法进行了研究,提出了锭坯轮廓特征提取方法。实验和测试表明,轮廓及直径、喷射高度的检测精度可达1 mm,算法平均运行时间为0.83 s,可以长时间稳定地在线检测沉积锭坯的轮廓。     

数字化高灵敏度荧光显微镜在AS2O3诱导MGC-803细胞核凋亡产生钙振荡研究中的应用

利用数字化高灵敏度荧光显微镜对As2O3诱导MGC-803细胞核凋亡过程中的钙振荡进行研究,通过图像中荧光强度随时间变化的规律反应钙振荡的频率和强度变化.结果证实As2O3诱导MGC-803细胞核凋亡过程中,的确引发了钙振荡,说明核钙参与了凋亡过程,并且钙振荡的频率以低频为主.对两相邻细胞核的钙振荡信号观察分析发现,两核钙强度变化曲线低频部分异常相似,几乎在同一时刻达到最高点和最低点.尽管钙波动的幅度不同,但基本频率相同,由此可初步预测钙信号以频率变化为表达特征.两细胞核凋亡呈同步化趋势,证明在受到As2O3刺激后,细胞核的凋亡不是个别现象.     

近红外光谱快速测定调合食用油成分含量可行性研究

针对市场食用油掺假现象,对近红外光谱快速测定食用油成分含量快速测定可行性进行研究。实验使用花生油和大豆油配制二元食用油调合油,使用花生油、菜籽油和大豆油配制三元食用油调合油。研究结果表明,二元调合食用油成分测量偏差为0.36%,三元调合食用油成分测量偏差为0.69%～0.83%,说明近红外光谱快速测定调合食用油成分含量是可行的。     

光纤光谱技术对猕猴桃品质及成熟度的无损检测

猕猴桃可溶性固形物含量(SSC)和硬度是评价其品质的关键参数,同时也是判别其成熟度的重要指标。为探究基于光纤光谱技术预测猕猴桃SSC、硬度和成熟度的可行性并寻求最佳预测模型。首先,采用光纤光谱(200～1 000nm)采集系统获取不同成熟期"贵长"猕猴桃的反射光谱,并测定SSC和硬度的参考值。接着,基于全光谱和参考值构建偏最小二乘回归(PLSR)和主成分回归(PCR)预测模型。然后,应用连续投影算法(SPA)和竞争性自适应重加权算法(CARS)选取特征波长,构建简化的多元线性回归(MLR)和误差反向传播(BP)网络预测模型。最后,通过偏最小二乘判别分析(PLS-DA)和简化的K近邻(SKNN)算法,构建预测猕猴桃成熟度检测模型。结果表明:CARS-BP模型对SSC的预测性能最优,其预测集决定系数R_P~2=0.90,预测集均方根误差(RMSEP)和剩余预测偏差(RPD)分别为0.64和3.22;CARS-MLR对硬度的预测性能相对最优,其R_P~2=0.83,RMSEP和RPD分别为1.67和2.47;PLS-DA模型对猕猴桃成熟度的检测性能最优,其正确识别率高达100%。该研究为水果品质和成熟度的无损检测提供重要指导。     

基于ADAMS的某乘用车悬架系统匹配计算

以前期开发的某乘用车为研究对象,运用机械系统动力学仿真软件ADAMS建立该车多体动力学模型,详细介绍悬架系统刚度与阻尼的匹配计算及验证过程,并根据国家标准对匹配结果进行整车仿真分析与评价.结论 表明,在前后悬架偏频比值为0.83、前后减振器在0.6 m/s、速度阻尼比分别为0.22和0.36、前后悬架侧倾角刚度比值为1.47的匹配设计下,该车辆具有良好操稳平顺性,对该车后续的悬架系统设计开发和操纵舒适性的优化提供了理论依据.     

轴流泵飞逸转速特性试验研究

介绍对立式和卧式两种轴流泵模型装置进行的飞逸转速特性试验研究,试验结果表明在-6°～+6°叶片角范围内,单位飞逸转速随叶片角度减小而增加,飞逸转速随扬程提高而增加,飞逸转速是额定转速的0.83～1.4倍。     

白细胞图像的自动分割算法

根据白细胞核在其饱和度分量S和绿分量G中的分布特点,构造细胞变换图像,提取细胞核,实现白细胞的初步定位.对存在细胞粘连的细胞图像,利用细胞边缘的相位角变化来检测细胞粘连区域并除之,采用线性插值法拟合边缘曲线,得到封闭的白细胞边缘轮廓,最终提取白细胞.本算法可自动分割白细胞,具有很好的分割效果.     

模式识别技术在人民币检伪中的应用研究

纸币的防伪与检伪水平关系着国家的金融安全,研究模式识别技术在人民币检伪中的应用,是为了探究如何不断提高人民币真伪判定的准确率,从而为相关的设备开发奠定基础。首先对模式识别技术做了简要总结。从人民币宽度检测和磁性信号检测两个方面,对模式识别技术在人民币检伪中的具体应用进行讨论。针对货币检测过程中的信号变化,以宽度检测和磁性信号的检测为实例,对信号的采集、信号的处理、真伪的判断开展了研究。相关研究结果可以应用在线性CCD信号的处理和分析之中。为货币的真伪检测方法与判定策略提供了参考实例。     

水分检测技术及其在铁精矿中的应用展望

本文通过分析发现传统水分检测方法对于实现非接触在线测量存在着相当的不足。为实现微波技术检测铁精矿水分,阐述微波检测水分原理,并对微波检测水分技术的研究和应用现状进行分析和总结。最后讨论目前铁精矿水分微波检测研究中存在的问题和今后发展的方向。     

基于模式匹配及其参数自适应的PCB焊点检测算法

为了提高在线自动光学检测(AOI)系统检测印刷电路板(PCB)焊点的准确率和速度,对PCB焊点进行了研究。通过研究由特定结构光源和3CCD彩色相机获取的PCB焊点图像,基于常见的良品、多锡、少锡、假焊等焊点类型,提取焊点图像关键子区域的面积特征,在此基础上,建立了五种焊点类型的特征矩阵模型,并根据同类焊点相似程度最大为原则设计了检测焊点的模式匹配算法。此外,本文还给出了一种参数自适应方法对各检查项所用到的阀值参数进行学习与校正。在实验研究中,对含有1040个Chip焊点的PCB进行了检测,结果显示本文所提算法对焊点检测的准确率可达96.5%,检测所用时间为9秒。研究结果表明,本文算法具有较高检测准确率和检测速度。     

AutoIHC‐scoring: a machine learning framework for automated Allred scoring of molecular expression in ER‐ and PR‐stained breast cancer tissue

In prognostic evaluation of breast cancer Immunohistochemical (IHC) markers namely, oestrogen receptor (ER) and progesterone receptor (PR) are widely used. The expert pathologist investigates qualitatively the stained tissue slide under microscope to provide the Allred score; which is clinically used for therapeutic decision making. Such qualitative judgment is time‐consuming, tedious and more often suffers from interobserver variability. As a result, it leads to imprecise IHC score for ER and PR. To overcome this, there is an urgent need of developing a reliable and efficient IHC quantifier for high throughput decision making. In view of this, our study aims at developing an automated IHC profiler for quantitative assessment of ER and PR molecular expression from stained tissue images. We propose here to use CMYK colour space for positively and negatively stained cell extraction for proportion score. Also colour features are used for quantitative assessment of intensity scoring among the positively stained cells. Five different machine learning models namely artificial neural network, Naïve Bayes, K‐nearest neighbours, decision tree and random forest are considered for learning the colour features using average red, green and blue pixel values of positively stained cell patches. Fifty cases of ER‐ and PR‐stained tissues have been evaluated for validation with the expert pathologist's score. All five models perform adequately where random forest shows the best correlation with the expert's score (Pearson's correlation coefficient = 0.9192). In the proposed approach the average variation of diaminobenzidine (DAB) to nuclear area from the expert's score is found to be 7.58%, as compared to 27.83% for state‐of‐the‐art ImmunoRatio software.     

Histological analysis of the alterations on cortical bone channels network after radiotherapy: A rabbit study

The aim of this study was to evaluate the effects of radiotherapy in cortical bone channels network. Fourteen rabbits were divided in two groups and test group received single dose of 15 Gy cobalt‐60 radiation in tibia, bilaterally. The animals were sacrificed and a segment of tibia was removed and histologically processed. Histological images were taken and had their bone channels segmented and called regions of interest (ROI). Images were analyzed through developed algorithms using the SCILAB mathematical environment, getting percentage of bone matrix, ROI areas, ROI perimeters, their standard deviations and Lacunarity. The osteocytes and empty lacunae were also counted. Data were evaluated using Kolmogorov‐Smirnov, Mann Whitney, and Student's t test (P < 0.05). Significant differences in bone matrix percentage, area and perimeters of the channels, their respective standard deviations and lacunarity were found between groups. In conclusion, the radiotherapy causes reduction of bone matrix and modifies the morphology of bone channels network. Microsc. Res. Tech. 73:1015–1018, 2010. © 2010 Wiley‐Liss, Inc.     

Tight junctions in Gerbil von Ebner's Gland: Horseradish peroxidase and freeze‐fracture studies

The permeability of tight junctions to horseradish peroxidase (HRP) and the freeze‐fracture appearance of junctional structures were investigated in the von Ebner's gland of gerbils. In the tracing study, HRP was either administered topically on the dorsal surface of tongues or injected subepithelially into the connective tissue of vallate papillae for 5–30 min. Lingual tissues containing the von Ebner's gland were sectioned and examined by light and electron microscopy. In von Ebner's glands, the reaction product for HRP was found in the intercellular and interstitial spaces, whereas HRP appeared to penetrate the tight junctions and the reaction product was localized in the lumina of serous acini. In contrast, the staining for HRP that delineated the boundary of epithelial cells was frequently observed in the superficial layers of the lingual epithelium but not the underlying tissues while applying HRP topically. Freeze‐fracture replicas of acinar cells revealed that the tight junction had a depth of 0.815 ± 0.023 μm, and 4–6 parallel strands on the protoplasmic fracture face, with a branching network of joining strands with interruptions, interconnections and high linear strand density apically, and corresponding grooves on the extracellular face. Quantitative analyses showed a greater number of strands (7.217 ± 0.326) in gerbils compared to those of acinar cells (3.86 ± 0.22) in mice. These results demonstrate that the tight junctions in the gerbil von Ebner's gland is permeable, and that specific species differences in tight junction structures may be associated with the mechanism for survival in an extremely dry environment. Microsc. Res. Tech. 78:213–219, 2015. © 2015 Wiley Periodicals, Inc.     

Regular molecular nano-dot patterns for RW-data storage in the optical near field

The geometric structure of a biopolymer network impacts its mechanical and biological properties. In this paper, we develop an algorithm for extracting the network architecture of three‐dimensional (3d) fluorescently labeled collagen gels, building on the initial work of Wu et al., (2003) . Using artificially generated images, the network extraction algorithm is then validated for its ability to reconstruct the correct bulk properties of the network, including fiber length, persistence length, cross‐link density, and shear modulus.     

Short‐term effect of cryotherapy on human scleral tissue by atomic force microscopy

This study investigated the inflammatory effect of cryotherapy application on collagen matrix network in human infant sclera. Donor scleral tissues taken from three infant patients divided into five groups: control group, sham‐treated group, and three cryotreated groups. In the cryotherapy groups, the sclera was treated for 5 s, 10 s, and 20 s with ?80°C freezing by a cryosurgical system. The cryotreated reactions were examined using double histological analysis with hematoxylin‐eosin and Masson's trichrome, and atomic force microscopy analysis to quantify the diameter and D‐banding of collagen fibrils. The infant scleral tissues treated with cryotherapy showed a significantly increased collagen density associated with inflammatory response (p < 0.05), increased fibril diameter (p < 0.005) compared to the scleral tissues in the control group. The results directly suggest that the cryotherapy affects the morphology of scleral collagen. SCANNING 35:302‐307, 2013. © 2012 Wiley Periodicals, Inc.     

基于近似似然的频响函数不确定性模型修正

针对流程工业复杂机电系统状态不断更迭、性能出现漂移等问题，提出了一种基于自组织特征映射网络的系统服役过程动态标记方法。首先，构建多变量间耦合关系网络，并在此基础上提取网络特征；其次，将动态标记过程分为状态主动更新过程和状态主动更新过程两个阶段，状态被动更新过程通过不断训练自组织特征映射网络来适应系统新状态出现及性能漂移等情况，状态主动更新过程可用于消除系统已消亡状态对网络模型产生的影响；最后，通过分析实际化工生产系统监测数据对所提方法进行有效性验证。实验结果表明，该方法可有效标记复杂机电系统服役过程中不断变化的多种状态，并建立符合系统动态演化过程的状态标记知识库，从而为系统状态辨识和预测提供可靠依据。     

光纤光梳温度反馈控制方法研究

为了解决光学频率梳长时锁定困难的问题,对光学频率梳重复频率(f_r)与载波相位偏移频率(f₀)的控制方法进行了改进。采用上、下两块半导体制冷片(TEC)对振荡器局部环境进行温度控制,并微调TEC温度将f_r与f₀漂移量分别稳定在10 Hz和600 Hz以内。利用锁相电路反馈控制有效腔长和泵浦光功率对f_r与f₀进行了精密锁定。光学频率梳在170 h时间内连续锁定,f_r与f₀抖动标准偏差分别为0.83 MHz和280 MHz。结果表明,该方法可以实现光学频率梳的长时锁定,增强其环境适应能力。     

<Emphasis Type="Bold">The Optimal Design of a Cooling System for a Die-Casting Die With a Free Form Surface</Emphasis>

This study is on the finite element and abductive network method application to die-casting dies with free-form surfaces. The study aims to find the optimal cooling system parameters and decrease in deformation of a die-casting die. In order to avoid the numerous influencing factors, the free-form surface of a die-casting die is created as a non-linear Eq. of a polynomial function. The parameters of the cooling system, including the channel space and channel diameter, are adjusted according to the non-linear Eq.. An abductive network has been built for modelling the die-casting cooling parameters. The abductive network is composed of a number of functional nodes. Once the cooling system parameters are given, this network can predict the deformation of the die-casting accurately. A simulated annealing optimisation algorithm with a performance index is then applied to the neural network for searching for the optimal cooling system parameters and to obtain a satisfactory result.     

A hybrid approach to the development of a multilayer neural network for wear and fatigue prediction in metal forming

In this paper an approach to surface damage prediction is proposed for the case of metal forming. The method is mainly based on three fundamental stages: (a) the detection of a feasible physical model which is able to give some important understanding of the phenomenon, although with limited generality; (b) the extensive development of an organized experimental campaign, which is necessary to tune up the developed model; and (c) the organization of an efficient and intelligent way of data collecting. The three aspects of the research work have been integrated by means of a neural network which is trained by using data coming from the real plant, from the standard tribometers, and from the reference numerical model. In this sense, the neural network is indented as hybridized. Predictions are shown to be very close to the experimental data obtained in the production plant. The method is useful for minimizing the number of experiments in the process of materials and treatment selection, and in maintenance.     

基于神经网络的悬架试验系统研究

针对现有悬架设计及实验不一致问题以及基本型Elman网络忽略了输出层节点的反馈,只能满足一阶线性动态系统信号处理,而不能满足多层网络、多阶系统的需求,提出了一种改进型Elman网络;改进后的网络增强了关联层以及输出层的反馈,把反馈增益作当作连接权值来实施网络训练,训练后的网络不仅比例系数和积分系数具有时变性,还具有自适应性强、学习效率高、逼近精度高等特点。建立了基于改进型Elman神经网络PAC控制器,对六自由度悬架试验平台系统进行控制研究,分析了悬架阻尼、非悬挂质量、悬架刚度、轮胎刚度等参数对时域内轮荷利用率和频域内相位角的影响,通过整车实验证明:悬架参数的匹配可以有效地改善车身振动,降低悬架动挠度、轮胎动载荷,提高乘坐舒适性和车辆行驶安全性,协调整车综合性能。