这个场里没有旋度，旋度是不度量拉伸之类的东西的。
另一个向量场，是通过计算第一个向量场的旋度得到的，计算旋度之后，就可以得到一个不同的向量场。
That other field is given from the first one just by taking its curl So, after you take the curl, you obtain a different vector field.
关于旋度的更多介绍，设有一速度场，我们知道旋度是测量旋转影响的。
More about curl.If we have a velocity field, then we have seen that the curl measures the rotation affects.
并且，在星系的红色旋臂和旋臂间螺旋状的轮辐中可以看到被新生恒星加热的尘埃。
And, the galaxy's red spiral arms and the swirling spokes seen between the arms show dust heated by newborn stars.
使腕骨立起来垂直地板，将体重放在小臂骨的边缘，小臂既不要内旋也不要外旋。
Align the wrists perpendicular to the floor and center your weight on the edge of the forearm bone, rolling neither in nor out.
对于那些发旋情况严重的人们，建议让理发师或发型师把他们的干枯头发减短，这样的话，头发就会垂下了使发旋处不翘。
For guys with bad cowlicks, I suggest asking your barber or stylist to cut the hair dry so there's no water weight on the hair that will unnaturally hold the cowlick down.
这就是F的旋度，在实际应用中，如果你必须计算一个向量场的旋度，不要尝试记忆这个公式。
And that is indeed going to be the curl of F. in practice, if you have to compute the curl of a vector field, you know, don't try to remember this formula.
和平面上的旋度的一个重要的不同点是，这里向量场的旋度，仍然是一个向量场。
Now, an important difference between curl here and curl in the plane is that now the curl of a vector field is again a vector field.
它跨度近240光年，位于猎户座旋臂里，离地球3,800光年远；而我们的太阳系也在银河系同样的旋臂中。
It is located 3, 800 light-years away from Earth, inside the Orion spur — the same partial spiral arm of the Milky way where our solar system is located. The nebula is nearly 240 light-years across.
这个多山岛屿的大部分地区都被笼罩在云雾之中，苔藓将繁茂的森林覆盖得严严实实，这儿也是多姿多彩的夏威夷旋蜜雀的故乡，夏威夷旋蜜雀是一种濒临灭绝的鸟类。
Large parts of the mountainous island are swathed in cloud. These lush and mossy forests are home to the colorful Hawaiian honeycreeper, an endangered bird species.
庭院的高墙和较高的温度导致这架黑鹰在其自身的旋翼洗流中下坠。旋翼洗流是一种“具有动力的下坠”，这是种很危险的空气动力学状态。
The high walls of the compound and the warm temperatures had caused the Black Hawk to descend inside its own rotor wash-a hazardous aerodynamic situation known as "settling with power."
沃利斯称：“驾驶旋翼飞机很安全，即使引擎停转，旋翼还会继续转动，所以可以安全着地。”
Wallis said:" They are one of the safest machines to fly because, if the engine stops, the rotors keep turning and you can land."
直升机旋翼既要提供升力又要提供向前的推力是造成这一情况的主要原因，同时旋翼产生的震动也是一个让直升机飞不能高速飞行的部分原因。
That is partly because of increasing vibration, but mainly because the spinning rotor blades provide both lift and propulsion.
因此，它们在性质上的唯一区别应该可通过观测两种香芹酮的气味和旋光仪中旋光度的符号而得知。
Hence, the only difference in properties one should observe for the two carvones are the odors and the signs of rotation in a polarimeter.
双螺旋桨在向前推进时向内旋还是外旋？
罗恩花了一个又一个晚上，用魔杖在收音机顶上敲出各种节拍，把调谐钮旋来旋去。
Ron spent evening after evening using his wand to beat out various rhythms on top of the wireless while the dials whirled.
旋花：任一种分布广泛的旋花属的通常为蔓生或对生的植物，开有漏斗状花朵，包括几种野草和几种作为观赏植物栽培的植物。
Convolvulus: any of various mostly trailing or twining plants of the widespread genus convolvulus having funnel-shaped flowers and including several weeds and a few grown as ornamentals.
水模型实验结果表明，与无旋流情况相比，施加旋流后循环流量显著增大。
The water model experiments show that the circulation flow rate with swirling flow increases significantly.
发现旋光基质有外消旋作用。
Racemization is found with optically active substrate substrates.
方钻杆旋转器已经很大程度地替代了旋链，而正是旋链造成了钻台上的大部分伤害事故。
The kelly spinner has largely replaced the infamous spinning chains, which were responsible for numerous injuries on the rig floor.
利用螺旋理论的规律可以准确预测其旋光方向，也可以计算其旋光度。
On the basis of helix theory, the rotatory direction can be predicted precisely and the optical rotation can be calculated, too.
在腕屈、桡偏、旋前和旋后方面，动态固定器组恢复更快。
Wrist flexion, radial deviation, and pronation-supination were regained significantly faster in the dynamic fixator group.
它们的旋光方向和旋光度大小都是由其分子的立体结构所决定。
Their rotatory direction and optical rotation are determined by the molecular stereostructure.
它们的旋光方向和旋光度大小都是由其分子的立体结构所决定。
Their rotatory direction and optical rotation are determined by the molecular stereostructure.
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