流动注射悬浮液脉冲进样--火焰原子吸收光谱法测定中草药生地中的铁和锌

以流动注射悬浮脉冲进样－火焰原子吸收光谱法进行了中草药生地中铁和锌元素的测定，生地被干燥，粉碎，过筛后加入琼脂溶液制成悬浮液，然后用流动注射脉冲送入雾化器。实验考察了仪器工作条件，样品悬浮液制备和方法的准确性，用标准加入法测定，该法简便，快捷，测定结果与灰化法一致。     

罗茨流量积算仪的低功耗设计

罗茨流量积算仪用于气体流量的自动化计量。本文引入天然气压缩系数Z，对理想气体状态方程进行修正，提高了流量计温压补偿的准确性。文中阐述了积算仪的硬件和软件设计方案，着重介绍积算仪低功耗设计方面的尝试；利用MSP430单片机的低功耗和高集成度的优点、软件设计的低功耗实现等。结果表明，泫系统运行稳定，检测精度高。具有一定的实用性和推广价值，适于电池供电和远程应用场合。     

大尺寸直径非接触光电检测系统研究

提出了一种基于激光位移测头的大尺寸直径光电测量系统，可用于直径达φ52200mm的大尺寸工件的非接触测量。文章详细论述了测量系统结构、工作原理及同轴度测量方法，并对影响测量精度的主要误差来源进行了分析，结果表明测量精度达0．02mm。     

基于MEAN-SHIFT和SVM的血细胞图像分割

提出一种新的血细胞图像分割算法,结合无监督和有监督模式识别技术,利用颜色快速提取感兴趣的有核细胞.首先通过mean-shift过程寻找RGB颜色空间中的细胞核、红细胞和背景聚类峰(局部密度最大区域),其中的细胞核图像区域经过适当形态学膨胀后可以得到部分胞浆像素;然后细胞核聚类峰和部分胞浆颜色组成正特征子集,而红细胞和背景聚类峰附近颜色组成负特征子集,训练一个两分类SVM,得到的分类模型随后对图像的颜色空间向量分类,实现细胞区域整体提取.通过颜色量化手段,能够显著减少训练集的颜色向量数量,实现SVM实时训练和分类.借助于mean-shift鲁棒的特征空间分析性能和SVM出色的小样本学习推广能力,该方法对图像颜色变化、染色条件差异等鲁棒性强,无过度分割现象,分割速度和效果均优于流域变换方法.骨髓和外周血涂片的分割试验证明了方法的有效性,已应用于实际图像处理系统.     

考虑共因失效的机械零部件可靠性模型

共因失效作为相关失效的一种重要形式,普遍存在于机械零部件和系统的失效中.研究了机械零部件中由载荷所引起的相关失效现象,分析了相关失效产生的原因,运用应力-强度干涉模型,建立了存在多种失效模式的机械零部件可靠性模型,并运用该模型对齿轮的可靠度进行了实例计算.     

数控系统现场总线可靠通信机制的研究

现场总线的应用是数控系统发展的必然趋势.为满足数控系统的高可靠通信需求,在分析数控系统加工精度与可靠通信关系的基础上,设计一种现场总线可靠通信机制.针对该机制,建立数控系统通信可靠性评价的指标,提出以无故障通信时间来衡量现场总线通信的可靠程度;通过概率统计方法,对该机制的可靠性进行数学分析,得出现场总线通信可靠性与通信...     

Three dimensional cutting force analysis in end milling

The analysis of cutting forces plays an important part in the design of machine tool systems as well as in the planning, optimization, and control of machining processes. This paper presents a three-dimensional model of cutting forces in peripheral end milling in terms of material properties, cutting parameters, machining configuration, and tool/work geometry. Based on the relationship of the local cutting force and the chip load, the total cutting force model is established via the angle domain convolution integration of the local forces in the feed, cross feed, and axial directions. The integration is taken along the cutter axis and summarized across the cutting flutes. The convolution integral leads to a periodic function of cutting forces in the angle domain and an explicit expression of the dynamic cutting force components in the frequency domain. The closed-form nature of the expressions allows the prediction and optimization of cutting forces to be performed without the need of numerical iterations. To assess the fidelity of the analytical model, experimental data from end milling tests are presented in the context of three dimensional time waveforms, power spectra, and phase angles, in comparison to the values predicted by the model.     

Dynamic parallel machine scheduling with mean weighted tardiness objective by Q-Learning

In this paper, we discuss a dynamic unrelated parallel machine scheduling problem with sequence-dependant setup times and machine–job qualification consideration. To apply the Q-Learning algorithm, we convert the scheduling problem into reinforcement learning problems by constructing a semi-Markov decision process (SMDP), including the definition of state representation, actions and the reward function. We use five heuristics, WSPT, WMDD, WCOVERT, RATCS and LFJ-WCOVERT, as actions and prove the equivalence of the reward function and the scheduling objective: minimisation of mean weighted tardiness. We carry out computational experiments to examine the performance of the Q-Learning algorithm and the heuristics. Experiment results show that Q-Learning always outperforms all heuristics remarkably. Averaged over all test problems, the Q-Learning algorithm achieved performance improvements over WSPT, WMDD, WCOVERT, RATCS and LFJ-WCOVERT by considerable amounts of 61.38%, 60.82%, 56.23%, 57.48% and 66.22%, respectively.     

提高微压传感器灵敏度的深盆腔压力膜片研究(一)

表面微机械微小量程压力传感器采用多晶硅薄膜等有内应力的敏感膜片时，应力往往会使膜片的力学灵敏度大大下降，无法满足微量程测量的要求。波纹膜片可以消除或减小应力来提高灵敏度，但是其波纹结构本身又会造成力学灵敏度下降，从而部分抵消了应力消除的效果。提出一种新型深盆腔膜片结构，在消除应力的同时实现了比平膜片还高的力学灵敏度，可以提高微压传感器和微麦克风的灵敏度。采用解析和有限元 两种方法相结合的方法，对该种膜片进行了分析和研究。对比平膜和波纹膜结构，显示了深盆腔膜在力学灵敏度方面的显著提高。