矢量计算

A new brushless DC motor DTC scheme was studied to solve those problems associated with direct torque controlof brushless DC motor,such as difficulty to control flux and complexity to estimate torque.The flux hysteresis controller was ignored in the constant torque region and an improved method was proposed to make the estimation of torque easier.The proper stator voltage space vector was selected based on the output of the torque hysteresis controller and the sector which the current rotor flux locates in.

摘 要：针对无刷直流电机直接转矩控制中磁链观测困难、控制复杂等问题，提出了一种应用于无刷直流电机二二导通方式下的新型直接转矩控制方法：在电机基频以下调速时，略去了常规的磁链观测控制环节，改进了转矩计算方法，通过转矩滞环控制选择所施加的空间电压矢量。

Iii The form factors of heavy pseudoscalar meson decays to light vector mesons are calculated in light-cone QCD sum rules.

用光锥QCD求和规则方法计算了重赝标量介子到轻矢量介子的跃迁形状因子。

The motionless backgroup situation usually happens at the video camera parked to opposite quiescent condition , the first wipe off yawp by using pretreatment method,the second using the method of difference Statistic in two frame to analyse and compute background , Above this base to utilize the resumeed background and present frame message detect movement target and it"s movement track ; In dynamic backgroup movement image,it is very difficult to exactly compute ground since the background is varied complexly , the article research the optical flow model、 background model、 moving object detection based on entropy,and depart target from background in movement picture , detect moving target and plain it"s track.

静止背景的情况通常发生在摄像机相对静止状态，首先用预处理的方法去除噪声，其次采用帧间差分统计的方法进行分析计算背景，在此基础之上利用恢复的背景及当前帧的信息检测运动目标及其运动轨迹；对于动态背景的运动图像，由于背景是不断变化且呈现出复杂的特征，因此很难准确求出静止背景，本文在光流矢量场和配准方法的基础上探讨研究了光流模型、背景模型和基于熵的方法，在动态图像上分离不同的目标与背景，直接检测出运动目标并画出相应的轨迹。针对运动图像的复杂性，本文提出了构建模型知识库的设想。

First, a smooth curve is obtained from the data by curve fitting with the method of non-linear least squares fit. Then the tangent vector and the radius of curvature of each point on the curve can be calculated for the error evaluation. With the fitted curve, the focusing state of the aspheric lens can be obtained by the method of ray tracing.

主要过程为首先采用非线性最小二乘拟合的方法进行曲线拟合，并计算出曲线上各点的切矢量和曲率半径，分析它们的误差，最后对拟合后的曲线用光线追迹的方法得到非球面镜的聚焦情况。

The Luneburg lens antenna is composed of a series of concentric shells of constant permittivity. Considering the complexity of numerical calculation, this paper presents a closed-form approach, which combines the spherical vector wave method and the reciprocity theorem.

摘要伦伯透镜是一种球形分层介质天线，考虑到数值计算的复杂性，本文提出用矢量球面波理论和互易原理相结合，分析其性能。

The hybrid method first calculates the scattered fields of the Luneburg lens using the spherical vector wave method. Then it transforms the calculated results into the radiation fields in the far region using the reciprocity theorem.

该方法首先用矢量球面波理论计算平面波入射到多层介质球的散射场，在此基础上，用互易原理将散射场转变成天线的远区辐射场。

TE mode diffraction characteristics of surface-relief grating having different symmetrical profiles (rectangular, sinusoidal, triangle, trapezoidal profile) are calculated with rigorous second order vector couple-wave theory, the law of diffraction efficiency as a function of grating groove depth are analyzed: in a specific condition, diffraction efficiency might be close to 100%.

本论文采用严格的二阶矢量耦合波理论计算了矩形、正弦、三角形、梯形等对称面形蚀刻光栅的TE模偏振的衍射特性，分析了光栅的衍射效率随着沟槽深度变化规律。

The FDTD formulations of dispersive medium are deduced. Using shift operator method, the recursive relation for 〓 and 〓 available for FDTD computation of plasma coating is obtained.

推导了色散介质FDTD的递推公式，给出了时域计算中电位移矢量〓和电场强度〓之间关系的移位算子法，并用该方法得到了本构关系在离散时域的递推关系。

When the optimum phase-array vector is used in the real communication , the calculating complexity is reduced to the lowest degree .

将此最优相位序列矢量用于实际通信，可使得实际通信时的计算复杂度降到很低程度。

Parameter S11 was measured with microwave sensor and vector network analyzer, which was used to calculate relative complex permittivity.

制备了一定含水率不同浓度的CuCl2的PVA样品，用微波矢量网络分析仪和微波传感器测量S11参数，计算得到相对复介电常数。

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。