故障的

To make paper more systematic and practical, this paper has first introduced the development history of CT equipment, then, elaborate construction of system and theworking principle of CT equipment systematically, including the property of X-ray, the absorption law of X-ray for materials, the reconstruction principle of CT image, the structure of software and hardware for CT equipment. Finally, with 2 CT systems that we used, statistic and analysis of all the malfunctions which have carried out in passed 10 years was given, and according to the systematic parts of fault located, classify the malfunctions, then elaborate their working principle one by one, analyze the regularity and the characteristic of each malfunction, and put forward specific prevention method and measure for the malfunction.

为了使论文更具系统性和实用性，本论文首先介绍了CT设备的发展史，然后比较系统地阐述CT设备的工作原理及系统结构，包括X射线的特性和物质对x射线的吸收规律，CT图像的重建原理，CT设备的软、硬件结构等，最后以我们所使用的2台CT为例，对10余年来所出现的故障进行了全面的统计分析，并按故障所处的系统部件进行分类，然后逐个阐述其工作原理，分析其故障的特点和规律，并就这些故障提出具体的预防方法和措施。

Host system failures are many reasons, such as the motherboard's own fault or I / O bus fault may lead to a variety of add-in card system is not normal.

主机系统产生故障的原因很多，例如主板自身故障或 I/O 总线上的各种插卡故障均可导致系统运行不正常。

The interclass difference matrix is calculated by using the fault class feature data from simulation in order to determinate the ambiguity sets.

算法利用电路仿真故障特征数据计算故障的类间差异矩阵，从而完成故障类模糊集的确定。

Based on the analysis on the relationship of the positive and the negative sequence impedance, also the positive and negative fault component current under simple and duplicate fault conditions, a cross-country fault identifier is proposed in this paper.

同杆并架输电线路故障的主要特点是有跨线故障，而当系统发生跨线故障时如果没有正确识别出来，那么保护就很有可能无选择性同时切除两条线路，从而对系统的安全稳定运行造成恶劣影响。

This device consists of three elements, a high voltage generator, a signal sampling element and a panel operation element.

通过对模拟故障和现场实际故障的多次测试表明，基于直流电阻法所研制的电力电缆护层故障测试仪在功能和技术指标上均达到了设计要求。

Aimed at the problem of choosing the initial value when the Newton method is used to compute the controlling unstable equilibrium point, a practical and rigorous solving scheme was presented: by identifying the controlling load bus of the given fault, and using the Thevenin equivalent circuit to represent the rest of the system at the state of the post disturbance stable equilibrium point, using the steady equivalent circuit to represent the induction motor in composite load, and then using the torque characteristics of induction motor, a point near the CUEP is gained to be the initial value. The second order normal forms was used to approximate the stable manifold of CUEP, and the local approximating boundary of the region of attraction of the post disturbance stable equilibrium point was gained. Then just by simulating the state of the system at the fault clearing time, the transient voltage stability of the system could be determined.

针对采用牛顿法求取故障后系统主导不稳定平衡点(controlling unstable equilibrium point，CUEP)存在的初值选取难题，提出一种实用但不失严谨的解决方案：通过识别给定故障的主导负荷母线，对主导负荷母线以外系统由故障后稳定平衡点处的状态进行戴维南等值，对负荷中感应电动机部分采用其稳态等值电路，再由感应电动机的转矩特性求得CUEP附近的一个点作为近似的CUEP，以此为迭代初值可靠求得CUEP；采用二阶正规型来近似CUEP的稳定流形的方法求得近似的局部吸引域边界；由仿真得到故障清除时刻系统的状态并根据该状态是否位于吸引域内判断系统的暂态电压稳定性。

The multi-dimensional signals measured by sensors with a machine working under normal condition or fault condition, can be used to build Q statistic and T^2 statistic respectively to detect the state of the machine. Meanwhile, the feature vector is constructed by the Q value and the T^2 value, the geometrical distance between the normal feature vector and the feature vector H when the machine goes wrong is used to realize the fault location. The results show that the method is feasible.

利用多个传感器测量的异步电机多维信号参量，构建电机在正常工作和发生故障时的Q统计和T^2统计，以实现电机的状态检测；利用Q统计和T^2统计值构建电机的状态特征向量，通过比较度量当前电机的特征向量与电机发生故障时的特征向量H的几何距离来实现电机故障的定位与分离实验证明，该方法可以有效地实现故障的诊断与分离。

The frequency changer Surpasses the voltage fail safe is the frequencychanger middle DC voltage after achieved the degree of hazard adoptsprotective measures, this is a big flaw which the frequency changerdesigns, causes this breakdown reason in the frequency changer actualmovement many, may adopt the measure are also more, when processesthis kind of breakdown must analyze the clear breakdown reason, haspointed takes the corresponding measure to process.

变频器过电压故障保护是变频器中间直流电压达到危险程度后采取的保护措施，这是变频器设计上的一大缺陷，在变频器实际运行中引起此故障的原因较多，可以采取的措施也较多，在处理此类故障时要分析清楚故障原因，有针对性的采取相应的措施去处理。

The frequency changer Surpasses the voltage fail safe is the frequencychanger middle DC voltage after achieved the degree of hazard adoptsprotective measures, this is a big flaw which the frequency changerdesigns, causes this breakdown reason in the frequency changer actualmovement many, may adopt the measure are also more, when processesthis kind of breakdown must analyze the clear breakdown reason, haspointed takes the corresponding measure to process.

摘 要：摘要变频器过电压故障保护是变频器中间直流电压达到危险程度后采取的保护措施，这是变频器设计上的一大缺陷，在变频器实际运行中引起此故障的原因较多，可以采取的措施也较多，在处理此类故障时要分析清楚故障原因，有针对性的采取相应的措施去处理。关键词变频器电动机整流 Abstract ：The frequenc。。

Based on the work principle of the speed reducer ,the paper studies the produced mechanism of the vibration signal,the fault forms and the different type of vibration caused by the faults.

文章以减速机工作原理为基础，研究了减速机振动信号产生的机理、减速机故障的形式，以及由于故障的不同引起的不同形式的振动，从减速机外部振动信号中获取故障特征信息，有效地实现了减速机的故障诊断。

Do you know, i need you to come back

你知道吗，我需要你回来

Yang yinshu、Wang xiangsheng、Li decang,The first discovery of haemaphysalis conicinna.

1〕 杨银书，王祥生，李德昌。安徽省首次发现嗜群血蜱。