矩

The building rules of GLCM （ the best gray levels and pixels interval） were confirmed by experiment. GLCM texture parameters of 300 wood specimens were calculated and assayed, and then placed into a Competitive Neural Network for classification output. The results are as follows: 1） GLCM parameters Angular Second Moment contrast , correlation , entr

以"角二阶矩"、"对比度"、"相关"、"熵"、"方差"、"逆差矩"作为描述木材纹理的特征参数是合适的。2）在比例为1：1的512×512木材图像情况下，生成灰度共生矩阵的最佳像素间距为4，最佳图像灰度级数为128.3）木材纹理图像灰度共生矩阵的"角二阶矩"、"相关"和"熵"值最大的方向为纹理方向。4）竞争神经网络的分类正确率为88％。

For Hu invariant moment having no scale invariance, two modified algorithms are proposed: one is based on the normalized central moment coming from the concept of image square and the other is based on constructing a new invariant moment.

主要贡献如下： 1。针对离散情况下Hu不变矩特征仅仅具有平移、旋转不变性，不具有比例不变性的问题，提出了两种改进算法：一种是从图像正方形概念演变而来的归一化中心矩的修正；另一种是重新构造新的不变矩特征。

Direct torque control is another high performance control technique of AC motor, it discard the decouple idea of vector control, but adapt flux oriented control and transient space vector theory, directly control stator flux and torque, it has the advantage of rapid torque response and less relying on stator parameters, but has the disadvantage of bigger torque ripple.

直接转矩控制技术是继矢量控制技术之后的又一种交流电机高性能控制技术，它摈弃了矢量控制中解耦的控制思想，采用定子磁链定向和瞬时空间矢量理论，直接对电机定子磁链和转矩进行控制，具有转矩响应快、对电机参数依赖小的优点，但它的不足之处就是存在转矩脉动。

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。

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。

The present invention relates to a method for heuristically starting up DC brushless servo electric machine, including the following steps of (1) after powerup of an increment type photoelectric encoder, electrifying a stator winding two by two with identical time interval to generate six-directional stator winding resultant magnetic fields;(2) detecting six different angles rotated by the rotor within identical tiny time interval by the photoelectric encoder;(3) selecting most positive value rotation angle from the six different angles, and determining maximum torque corresponding to the stator winding resultant magnetic field, and implementing servo startup using the maximum torque as constant starting torque;(4) after the zero-point signal of the photoelectric encoder occurring, switching to servo operation with normal constant torsion.

本发明直流无刷伺服电机试探启动方法，采用如下步骤：(1)增量式光电编码器上电后对定子绕组采用相同的时间间隔两两通电，顺序产生六个方向的定子绕组合成磁场；(2)由增量式光电编码器检测出转子在相同的微小时间间隔内分别转过的六个不同的角度；(3)从转子六个不同的角度中选出最大正值的转角，确定相应定子绕组合成磁场对应的最大转矩，并以该最大转矩为恒定启动转矩进行伺服启动；(4)当增量式光电编码器零点信号出现后，切换为正常恒转矩伺服运行。

The characteristics of image moments can be applied in manyfields. We apply Tebechbief moment characteristic to match replace of using graycharacteristic as primitives. An area moment has the property of unsensitive to transition,rotation and sealed change of area, the property of area moment is applied in the areamatching approach in our thesis, combined with a new constraint, and a novel area-basedmatching approach is proposed.

文中对Tchebichef正交矩能对图像进行精确重建的原理，利用点矩特征作为匹配基元对图像进行匹配，得到了较好的效果，并讨论了利用图像重建误差图像进行匹配的可能性和有效性；最后通过矩对区域的平移、旋转和尺度变化的不敏感特性，讨论了基于不变矩的区域匹配方法，通过引入相对位置约束提出了一种新的匹配策略。

An image can be better described by a small set of its pseudo-Zernike moments than any other types of moments such as geometric moments, Legendre moments, rotational moments, and complex moments in terms of mean-square error.

为了能使伪Zernike矩得到更广泛的应用，在详细分析伪 Zernike矩不变性的基础上，提出了伪 Zernike矩的改进方法，使改进后的伪 Zernike矩在保持旋转不变性的同时，还具有真正意义上的比例不变性，同时给出了部分的实验分析结果。

In this work, the N〓-broaden halfwidths of the pure rotation and v〓 band of water vapor have been calculated by using QFT theory, which involves the three intermolecular interactions: short range, dipole-quadrupole, and quadrupole-quadrupole (denoted as QFT〓).

本文首先利用考虑短程强相互作用势、电四极矩〓-电四极矩〓和电偶极矩〓-电四极矩〓相互作用的QFT方法，计算了水汽分子纯转带和V〓振动带谱线的氮分子碰撞加宽线宽，以及V〓振动带谱线线宽的温度依赖关系。

This paper introduces the control principle of the direct torque control system of an asynchronous motor, and proposes a new strategy to solve the problem of the large torque ripple and current ripple. The Matlab 6.5 simulation shows that it can solve the problem efficiently.

本文介绍了直接转矩控制系统的控制原理，并针对基于直接转矩控制的异步电动机运行时存在较大的电流及转矩脉动问题，提出一种新的控制方案，并基于Matlab 6.5对这种新方法进行仿真，仿真结果表明该方案能有效的解决电流及转矩脉动的问题。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。