超声弹性成像在肿瘤良恶性鉴别中的应用

超声弹性成像技术自问世以来,迅速发展并得到广泛的临床应用,已成为超声诊断的重要工具。本文对超声弹性成像在乳腺、甲状腺、前列腺、肝脏肿瘤的良恶性鉴别以及子宫、肾脏、淋巴结、涎腺、胰腺、胆囊良恶性肿瘤评估中的应用进行综述。     

Flow measurement based on the combination of swirler and differential pressure under slug flow

The alternating appearance of elongated bubbles and liquid slugs of slug flow in the pipe causes severe pressure fluctuation. As a result, measuring the flow rate of the slug flow with the throttling unit based differential pressure method is difficult. This paper investigates a new swirler-based flow measurement method in slug flow. The swirler converts the slug flow into a swirling annular flow, and the differential pressure method is used to measure the flow rate. The influences of gas and liquid flow rates on the differential pressure ΔP_X across the swirler as well as its downstream axial differential pressure ΔP_Z are investigated. ΔP_X^0.5 increases linearly as the liquid mass flow rate increases, and the slope of the curve increases as the gas mass flow rate increases. The influence of gas mass flow rate on ΔP_X^0.5 is comparable to that of liquid mass flow rate on ΔP_X^0.5. ΔP_Z^0.5 increases linearly with increasing gas/liquid mass flow rate, and the slope of the curve of ΔP_Z^0.5 with m_l differs slightly from the slope of the curve in single-phase water conditions. Based on the research presented above, new empirical correlations of mass flow rate based on ΔP_X and ΔP_Z are established respectively. The superficial liquid velocity ranges from 0.6 to 2 m per second, while the superficial gas velocity ranges from 2 to 6 m per second. If the gas mass flow rate and ΔP_X are known, the relative error of liquid mass flow is less than 3%. The relative error of the gas mass flow rate is less than 10% if the liquid mass flow rate and ΔP_X are given. The calculation accuracy of the flow measurement model using ΔP_X is better than the calculation accuracy of the flow measurement model using ΔP_Z.     

Approximation of the discharge coefficient of differential pressure flowmeters using different soft computing strategies

Due to its importance in flow measurement and instrumentation, as well as its frequent application in differential pressure flowmeters, orifice discharge coefficient (C_d) needs to be estimated precisely. In this study, different soft computing models (including multiple linear regression (MLR), group method of data handling (GMDH), multivariate adaptive regression splines (MARS), M5P tree model, and random forest (RF)) were employed for the first time in estimation of the C_d value, and their respective prediction performances were analyzed statistically. Coefficient of correlation (CC), mean absolute error (MAE), root mean square error (RMSE), scattering index (SI), and Nash–Sutcliffe model efficiency coefficient (NSE) were used as the statistical indicators for validating the performance of each soft computing model. The statistical indicators approved the superiority of the RF model over the other models, while the MARS model also showed a competitive prediction potential over M5P, GMDH, and MLR models. The findings of this computational study clearly demonstrated that the implemented soft computing strategy had the capability to be used in precise estimation of the C_d of the orifice meter, specifically, in situations where the measurement of the parameters in deterministic equation is not practically feasible.     

结核分枝杆菌抗原特异反应性白细胞介素-22在结核性胸膜炎鉴别诊断中的应用

目的 :研究胸液单个核细胞经结核分枝杆菌特异性抗原肽刺激后表达的白细胞介素-22(Interleukin-22,IL-22)浓度测定在结核性与恶性胸腔积液鉴别诊断中的价值。方法 :将确诊的52例结核性胸膜炎和35例恶性胸腔积液患者胸液单个核细胞分离后,使用结核分枝杆菌特异抗原肽(early secreted antigenic target-6,ESAT-6)、(culture filtrate protein-10,CFP-10)刺激培养,测定细胞培养液上清中IL-22和干扰素-γ(Interferon-γ,IFN-γ)浓度,对结果进行统计学分析。结果 :结核性胸膜炎组IL-22浓度明显高于恶性胸液组(P<0.01)。ROC曲线显示IL-22用于结核性胸膜炎的诊断敏感性、特异性和准确性分别为90.38%、80.56%和85.23%,其诊断效能与IFN-γ相当(P>0.05)。结论 :结核分枝杆菌抗原特异反应性IL-22测定可作为对结核性胸膜炎诊断的重要参考指标。     

往复式机械的故障诊断分析

往复机械具有结构复杂、激励源多,运行不平稳等特点,使用传统的故障诊断方法,具有明显的不足和弊端。对于这类问题,运用小波分析方法分析往复式活塞隔膜泵信号及往复式活塞隔膜泵振动诊断实施要点,提高了其故障诊断和状态监测的准确性,并将这种方法推广到其他类型的往复机械中。     

Study of the fractional order proportional integral controller for the permanent magnet synchronous motor based on the differential evolution algorithm

A tuning method of the fractional order proportional integral speed controller for a permanent magnet synchronous motor is proposed in this paper. Taking the combination of the integral of time and absolute error and the phase margin as the optimization index, the robustness specification as the constraint condition, the differential evolution algorithm is applied to search the optimal controller parameters. The dynamic response performance and robustness of the obtained optimal controller are verified by motor speed-tracking experiments on the motor speed control platform. Experimental results show that the proposed tuning method can enable the obtained control system to achieve both the optimal dynamic response performance and the robustness to gain variations.     

RBF网络在电力电子电路故障诊断中的应用

电力电子电路模型具有很强的非线性，通常对其进行故障诊断比较困难。而神经网络具有非线性．自适应性．并行性和容错性等．故可由神经网络来学习和存储电力电子主回路的故障信息和故障类型（或原因）之间的映射关系，并将其用于诊断．从而实现电力电子电路的故障诊断。     

小波包分析在柴油机故障诊断中的应用

运用小波包分析方法对柴油机缸盖振动信号进行预处理,并运用小波包频带的能量分析方法识别柴油机喷油雾化质量故障。在不同工况下的柴油机上测得两组振动加速信号,并对该信号进行分析,准确识别了故障。说明该方法对提取故障信息并进行诊断是行之有效的。     

设备故障诊断的模糊综合决策法

传统的故障诊断模糊综合决策法存在着３个不足：只由某一（而不是所有）征候决定诊断结果;权值的归一化引起由权值（而不是故障征侯）决定诊断结果：一种征候对所有故障取相同权值。给出改进的故障诊断模糊综合决策法模型,修正以上不足。将其用于液压泵２故障诊断综合决策法模型,修正以上不足。将其用于 泵故障诊断,得到正确的诊断结果,证明新模型的可靠性。     

基于ARM的嵌入式系统在数控设备故障诊断中的应用

分析传统数控设备故障诊断系统所存在的问题，将ARM嵌入式系统引入传统数控设备故障诊断领域，开发设计出一个集数据采集，信号处理，故障诊断和网路通讯等功能于一体的在线故障诊断仪，从而提高了现场诊断的能力，简化了传统诊断系统的结构，改善了系统的稳定性。     

轨道车辆门远程监控与故障诊断系统软件设计

为了增强轨道车辆门的运营可靠性,提高车辆门系统的维保效率,设计了轨道车辆门远程监控与故障诊断系统,该系统采用了模块化的设计思路,完成了下位机数据接收解析、数据处理、故障诊断、故障预警、数据展示等功能。该系统提高了轨道车辆门的智能化水平,改变了轨道车辆门的维保模式,使得传统的事后修、计划修转变为状态修。     

基于LabVIEW的旋转机械远程故障诊断系统研制

根据机组运行特点和现场要求,针对旋转机械,特别是电厂风机,设计并开发出了一套在线监测与远程故障诊断系统。通过对设备进行在线监测,可以实时掌握其运行状态及变化趋势,为实现机组的高效运行、状态判断和故障分析提供依据和保障。该系统以LabVIEW作为软件开发平台,同时采纳了神经网络故障诊断方法,界面友好,功能完善。     

基于证据理论的城轨车辆走行系融合故障诊断

针对城轨车辆走行系故障诊断只依赖于单一证据源造成的诊断准确率低的问题,研究利用证据理论进行走行系多证据源融合的故障诊断。经过对高冲突低信任度情况下悖论产生的原因分析,采用矛盾因子对合成规则进行了改进;针对城轨交通车辆走行系,分析了轴承和轮对所有可能发生的故障,建立了走行系轴承和轮对的识别框架;选择轴箱振动诊断、轨旁振动诊断和轴温诊断等3个证据源作为走行系融合诊断的证据源;采用专家经验法确定了不同证据源的基本信任分配函数。研究结果表明,采用单一证据源的故障诊断准确率较低或诊断对象少,而采用多证据源融合的故障诊断方法(在包含轮对和轴承两个对象情况下)的诊断准确率为80%,从而有效提高了城轨车辆走行系故障诊断的可靠性。     

旋转机械故障诊断专家系统的属性和求解策略的探讨

本文讨论了旋转机械故障诊断专家系统的属性,提出旋转机械故障诊断专家系统是正向求解问题的、模糊的、病态结构系统的观点.并针对其基本属性,提出以频域模糊聚类分析为正向推理求解策略的思想与基本框架.同时,对知识库的容量与提高病态结构系统确定性的关系作一探讨.     

An envelope analysis based on the resonance modes of the mechanical system for the bearing defect diagnosis

In this paper, an envelope estimation algorithm based on the resonance modes of the mechanical system is proposed and the exponential decay frequency of the envelope signal could be further estimated to be a quantified index for the bearing defect diagnosis. According to the vibration spectrum of the bearing system, the resonance frequencies in the range of its corresponding resonance modes could be initially designated and further revised. Under the assumption of stepwise functions for the envelope signals, the vibration signal could be decomposed into the sinusoidal function bases with fundamental frequencies at the corresponding resonance frequencies. Thus, the envelope signals could be retrieved by estimating the stepwise functions. In addition, the reconstructed signal with noise rejection could be derived from the envelope signals. According to the envelope signals, the exponential decay frequency is estimated to be the diagnosis index of the bearing running condition. In the simulated and experimental studies, it is found that the envelope estimation algorithm could be effectively applied in the signal processing for the bearing vibrations. In addition, the envelope spectra also show good consistency between the proposed method and the high-frequency resonance technique. Finally, it is shown that the exponential decay frequency could successfully be the quantified index for the bearing defect diagnosis.     

基于PCA-BP算法的汽车涂装线烘房系统故障诊断研究

针对汽车涂装线设备参数组合复杂化、高耦合性等特点造成的设备故障无法及时发现和排除的困难,对涂装线各设备结构、故障机理进行了研究,提出了基于改进PCA-BP算法的设备故障诊断方法。该实验以涂装线烘房加热系统为实例,首先建立了其PCA模型,通过对监测数据信息进行了二次降维,提取了最优特征信息;然后将提取的样本特征在BP网络中进行了充分训练,诊断输出设备运行状态值,实现了故障诊断的效果。研究结果表明,PCA-BP方法在保证原始监测特征主要信息不丢失的前提下简化了监测空间参数,同时避免了原始BP算法易陷入局部极值的缺陷,通过烘房加热系统验证了该方法能够有效地对设备故障进行诊断。     

架空电力线故障诊断系统的仿真数据生成算法

现代社会的发展对电力的依赖性越来越强,为了保障线路的稳定运行,深入进行线路故障诊断的研究显得非常重要.但是由于数据缺乏一致性、采集困难等问题,模型训练、测试数据的获取一直困扰着相关研究的开展.为此,提出了一种故障数据生成算法PFGA,利用该算法可以生成大量的设备故障数据、单元故障数据及架空电力线路故障数据.由于该算法运用了云模型及多智能体系统等机制,生成的故障数据除了包含一定的先验知识外还存在一定的随机性,故障数据也很好地体现了真实故障数据的层次关联性、多样性、动态性等特点.利用构建的贝叶斯诊断模型分别利用PFGA和其他算法生成的数据进行诊断,结果表明,PFGA生成的数据更符合现实状况,相应的诊断结果也更为可靠.此外,该算法对不同线路状况的适应性也较好,研究人员可以根据实际研究情况生成所需的架空电力线路故障数据,以满足各类故障诊断研究对数据的需求.     

往复压缩机故障诊断专家系统知识库的构建

分析了往复压缩机的故障表现形式，提出了在往复压缩机故障诊断专家系统中采用广义故障树知识表示方法，介绍了簇复压缩机故障诊断专家系统知识库的组成及其功能和特点。     

MSCT和MRI对胫骨平台骨折的临床诊断价值

目的 :考察MRI和MSCT对胫骨平台骨折的临床诊断价值,以及其在胫骨平台骨折AO分型方面的指导价值。方法 :以我院2009年5月至2013年11月间收治的183例胫骨平台骨折患者为研究对象,对其MSCT和MRI检查结果进行汇总分析。对比分析两种影像手段对不同AO分型的胫骨平台骨折的诊断情况。结果 :经手术和联用其它检查手段,最终确诊AO分型中B型骨折患者96例(B1型46例、B2型31例、B3型19例),C型患者87例(C1型50例、C2型22例、C3型15例)。MSCT和MRI的诊断结果显示,MRI和CT在B1型、B2型、B3型、C2型的检出比例和确诊精度均相似,且差异无统计学意义(P>0.05)。但在C1和C3型骨折的检出比例和确诊精度方面,则以MRI较为理想,且差异具有统计学意义(P<0.05)。在合并伤方面,MSCT和MRI的检出情况接近,差异无统计学意义(P>0.05)。治疗效果显示,参考MSCT和MRI诊断结果制定的治疗方案合理、可靠,表明MSCT和MRI在对胫骨平台骨折的诊治具有明确的临床指导价值。结论 :MSCT和MRI对不同AO分型的胫骨平台骨折和其合并伤均有较好的诊断能力。     

基于建模技术的企业管理自诊断系统的研制与开发

提出了一种基于建模技术的“中小企业管理自诊断系统”的开发背景和技术实现路线,说明了系统的基本功能以及软件系统的构成,即利用建模技术建立中小企业的组织机构、数据、功能／决策模型,通过数据诊断分析和知识库模型的比对,得出诊断结论和改进意见,进而指导企业进行管理改善和管理提升。同时提出,在现有经济发展环境下,科技服务部门应进一步拓宽服务领域,重视并引导多方资源及时“向中小企业输入管理技术”。