If you take a vector field that is a constant vector field where everything just translates then there is no divergence involved because the derivatives will be zero.
如果取的向量场是处处恒定的，所有点都是平移关系，所以没有散度，因为导数为零。
So, even if the speed is constant, that means, even if a length of the velocity vector stays the same, the velocity vector can still rotate.
因此即使速率不变，也就是说速度矢量的的大小不变，但它的方向可以做旋转。
And, in some cases, for example, if you know that the vector field is tangent to the curve or if a dot product is constant or things like that then that might actually give you a very easy answer.
例如，在某些情况下，如果已知向量场与曲线相切，或者内积是一个常数等等，那么结果将会很简单。
You can just multiply a normal vector by any constant, you will still get the normal vector.
一个法向量与任意常数相乘，还是法向量。
Then a voltage vector control scheme for induction motors based on constant stator flux is presented and it's nonlinear limitations are analyzed.
结合定子磁链控制，提出异步电机基于定子磁链幅值恒定的电压矢量控制方案，并对该方案的非线性局限进行了分析。
Subtract a constant from a vector's magnitude (shorten the vector) without using square root?
减去一个常数向量的大小（缩短向量），而不使用平方根?。
When the hue difference increased, the magnitude of color shift in test target decreased, but the deflection Angle of color shift vector from constant hue line increased.
当诱导域与试验域之间的色调差增大时，试验目标色觉位移的幅值减小，而色觉位移矢量偏离恒定色调线的偏向角却增大。
The control signals of invertor are produced by space vector modulation to achieve a small torque ripple and constant switch frequency.
以空间矢量调制方法来获得逆变器的开关信号，实现了小的转矩脉动和恒定的开关频率。
The stator flux-oriented vector controlling strategies of keeping stator frequency constant and capturing the maximum wind power are verified by experiment results.
实验结果验证了定子磁链定向的矢量控制策略既能保证定子输出频率恒定，又能较好地跟踪风力机的最大功率输出。
Then a vector control method with speed closed-loop and magnetic linkage closed loops put forward, which is based on the constant velocity by means of stator flux-oriented vector control.
在基于定子磁场定向的矢量控制恒线速运行控制方案的基础上，提出了一个速度闭环、磁链闭环的矢量控制方案。
Simulations show that the proposed observer can track rotor flux vector in a large speed range and be robust to the variable rotor time constant.
仿真结果表明该转子磁链观测器可以在较大速度范围内跟踪转子磁链矢量的变化，同时对变化较大的转子时间常数具有一定的鲁棒性。
According to this relationship, vector control system with energy-saving based on constant power factor was formed.
通过此关系，设计了基于恒功率因数的节能型异步电动机矢量控制系统。
We study the submanifolds with parallel mean curvature vector in a manifold of quasi constant curvature, and give two integrate inequalities.
研究了拟常曲率流形中具有平行平均曲率向量的子流形，给出了两个积分不等式。
Based on the basic equation of A. C. exciting alternator, the vector chart and power flow chart of the alternator are studied, and a method of variable-speed and constant frequency (VSCF) is proposed.
从交流励磁发电机的基本方程出发，通过对其矢量图和功率流程的研究，提出了变速恒频的实现方法。
The statistical average value of electronic polarization vector, magnetic moment, energy and paramagnetic susceptibility, which are proceeded under constant magnetic field, is discussed.
研究均匀磁场中电子的极化矢量、磁矩、能量和顺磁磁化率的统计平均值，以及在低温、强磁场极限和高温、弱磁场极限下的统计行为。
The compact submanifolds in quasi constant curvature Riemannian manifolds with Parallel Mean Curature Vector were studied.
研究拟常曲率黎曼流形中具有平行平均曲率向量的紧致子流形。
No convergent drawback of the weight vector due to choose the dispersion constant inaccurately in the normalized constant modulus algorithms (NCMA) is overcome.
该算法克服了在一般的常系数盲数字自适应算法中，由于估计幅值选择不合适，所造成加权矢量不收敛的缺点。
In an induction motor field orientation vector control system, the rotor time constant may be deviated due to motor temperature variation and flux saturation.
本文在异步电动机矢量控制系统中提出了一种基于转子磁场定向的转子电阻自适应辨识方法。
We discuss the first order linear differential equations with constant coefficients and give a new vector method of it.
讨论一阶常系数线性微分方程组通解问题，给出一种新的向量解法。
In rotor flux orientation control, rotor time constant T2 is a key issue of high performance vector control technology.
在转子磁场定向异步电机矢量控制系统中，正确的转子时间常数是高性能矢量控制系统的关键。
When frequency is up to the base frequency, the amplitude of voltage vector is restricted constant.
但当频率上升到基频后，定子电压受到变频器最大输出电压的限制而不能进一步提高。
The system adopts Unified Constant-Frequency with Vector Operation, to design 3-phase 3-wire parallel active power filter(PAPF).
系统采用基于矢量运算的恒频积分算法，设计三相三线并联型有源电力滤波器PAPF。
The system adopts Unified Constant-Frequency with Vector Operation, to design 3-phase 3-wire parallel active power filter(PAPF).
系统采用基于矢量运算的恒频积分算法，设计三相三线并联型有源电力滤波器PAPF。
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