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Based on varying process of generator terminal parameters after excitation fault, shortages of excitation protective principle of static stability boundary and asynchronous impedance boundary are analyzed. It proposed that excitation fault research relates to large-disturbance stability. Because dynamic power-angle character of generator after excitation fault is non-sinusoidal, there are differences between dynamic power-angle character and static state power-angle character. So it isn't ideal to protective operation result based on small-disturbance stability and static stability boundary criterion. At the same time, it proposed that asynchronous boundary impedance criterion is a constant reactive power circle moving adown j Xd′. It can ensure complete loss-of-excitation generator measuring impedance enter into the circle, but can't ensure the other condition measuring impedance including impossible losing synchronism enter. So loss-of-excitation protection would be maloperation when system voltage drops short and recovers or generator rejects load.③Based on stability principle, it puts forward setting conditions and calculation method of generator loss-of-excitation protection by direct measuring power-angle.

以励磁故障后发电机端的相关参数的变化为基础，通过对以静稳定边界和异步阻抗边界作判据的两类三种现行励磁保护在原理上存在的缺陷分析，发现：励磁故障是一个大干扰稳定性问题，励磁故障后的发电机的动态功角特性与静态功角特性有很大的差异，已远非正弦曲线，因此基于小干扰稳定性原理、以静稳定边界作判据的保护必然动作不理想；异步边界阻抗判据是一个下移j Xd′的等无功阻抗圆，它可以保证完全失磁后的发电机测量阻抗能进入该阻抗圆，但不能保证完全失磁之外的其它状态不会进入该阻抗圆，因此在系统电压短时下降或发电机突然甩负荷等情况下可能启动该保护使之误动。

LIU Hui's Cyclotomic Method is one of the greatest achievements in the history of mathematics in China,even in the world,in which the special approach to understand the infinity and the method to solve it are presented.

有的著作认为在极限公式limx→0sinxx=1的证明中，要用到圆的面积公式S=21Lr，而对后者的证明中必须要用到重要极限limx→0sinxx=1，从而犯了循环论证的错误。魏晋刘徽的"割圆术"是对无限问题的独特认识和致用的处理方式，是为证明圆面积公式而设计出来的一种方法。

ABSTRACT Based on theoretical analysis of axial compression of ring-shape specimen between two flat dies by an upper-bound technique,it is possible to carry out the measurement of both the friction coefficient of lubricant and the basic flow stress of the ring material under particular temperature and strain rate.

摘 要 根据圆环压缩的连续速度场上限定理的理论分析，通过圆环试样压缩前后的几何尺寸的变化，能测量润滑剂的摩擦因数和圆环材料的流变应力。

Because any reports on the active control of rotating disk haven't be seen in China up to now, and this experiment research is important, so the complete set of active control system of rotating disk are built independently. The push-pull type electromagnet is applied to control the vibration of the circular disk. The power amplifier circuit that can respond to wide scope in frequency from DC to AC is designed by improving the existing circuit. The sensor signal is first low-pass filtered, then the proportional control plus the differential control circuit easy used in practice are applied to finish the more effective control. The electromagnetism shield is used as possible to decrease the signal disturbance from the electromagnet to eddy sensor.

考虑到目前国内尚未见到有关旋转圆盘振动主动控制的相关报导以及实验的重要性，自行设计制作了一整套旋转圆盘振动主动控制系统：提出并采用推拉型电磁作动器来控制圆盘的振动；在改进现有电路的基础上，自行设计了具有较理想特性的驱动电磁作动器的功率放大器；根据实际控制环境的特点，设计了先进行低通滤波，再采用比例和实用的近似微分电路构成的控制器，并采用了电磁屏蔽来减小电磁铁对传感器的干扰，以实现更有效的控制。

On the base of the analysis of the static fbd under diametric compression , numerical analysis and compare are performed on the dynamic stress field of the brazilian disk and fbd used in the testing tensile strength under shpb

在对静态平台压缩巴西圆盘进行的数值分析的基础上，本文分析了shpb动态劈裂拉伸实验中巴西圆盘和平台巴西圆盘的动态应力场，并对结果进行了比较。

The basic principle is based on spherical astronomy and elementary geometry of the trajectory mapping method based on the observation of a celestial body zenith distance, then the ship is located in order to sing the next point as the center of this satellite zenith distance of the ship's position as the radius of the circle, observing the same two objects, or objects at different times of the two observations, we can get two ship's position round, then the ship must have been a point of intersection of two ship's position on the circle.

其基本原理是建立在球面天文学和初等几何中的轨迹作图法基础上的，观测一个天体的天顶距，则航船就位于以星下点为圆心，此星天顶距为半径的船位圆上，观测两个天体或者不同时间同一天体的两个观测值，就可以得到两个船位圆，则航船一定在两个船位圆的一个交点上。

Based on Collins integral formula and the expansion of the hard aperture function into a finite sum of complex Gaussian functions,the approximate analytical expression of the diffraction field of Gaussian beam by a circular disc is derived,and its characteristics are analyzed by the numerical calculation and numerical simulation.

基于圆孔光阑函数展开为复高斯函数和的方法，用Colins积分公式，导出了高斯光束照射下圆盘衍射的光场近似解析表达式，经计算机数值计算，对高斯光束照射下圆盘衍射的衍射特性进行了详细的分析

The ORF2 gene is the most important protein-code gene for porcine circovirus, and is the main gene differing porcine circovirus typel from porcine circovirus type2 (PCV2). To construct a specific PCR detecting method, we designed a pair of primers to amplify a partial fragment of ORF2 gene from PCV2, referring to fifteen strains complete genome published in Genbank. The PCR product was about 0.67kb in size detected by gelose gel electrophoresis.

猪圆环病毒的开放阅读框2(ORF2)是其主要结构蛋白的编码基因，也是区分猪圆环病毒1型(PCV1)和猪圆环病毒2型(PCV2)的重要基因，本研究参照GenBank已发表的15株PCV2基因序列，设计合成一对引物，对PCV2的ORF2基因进行PCR扩增，产物经琼脂糖凝胶电泳，呈现一条大小约0.67kb的特异条带，经条件筛选，建立了猪病料中PCV2感染的PCR检测方法。

The specialty is engaged in models arranges the packaging machinery equipment's design, the manufacture and the post-sale service, the main product has the high speed round loom, the automatic drawing machine, 6-12 shuttle color striped cloth braiding machine, the 2-4m assembly, the round silk wiredrawing unit, the gunnysack round loom, to drench the membrane coating machine, to blow the membrane machine, the tearing membrane to hit series packaging machinery products and so on wrapping tape machine.

专业从事塑编包装机械设备的设计、制造和售后服务，主要产品有高速圆织机、自动拉丝机、6-12梭彩条布编织机、2-4m复合机、圆丝拉丝机组、麻袋圆织机、淋膜涂布机、吹膜机、撕裂膜打包带机等系列包装机械产品。

According to topographic information of Dongyang and Wanshou which are tentatively chosen as the sites to assemble grounding poles,the selection of d/D ratio,namely the ratio of radius of two adjacent toroids,of standard triple toroidal grounding poles,the burial depth characteristics of each sub-toroids and the feasibility of adopting such type of poles are researched.

分析了直线形、星形和圆环形3种常见水平接地极的特点，结合溪洛渡、向家坝直流换流站初选东阳和万寿极址的地形资料，对标准3圆环接地极的环径比例选择、各子圆环的埋深特性及采用该电极型式的可行性进行了分析研究。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。