环

Six 3,6-dichloropyridazine-derivatized cinchona alkaloid catalysts were synthesized and applied in IFB reaction.

二氢奎宁二聚体2c最差(56%ee)，与环己二酮相比，环戊二酮作为反应原料时，产物的ee值降低。

Much of the gas in the disk of the Circinus spiral is concentrated in two specific rings -- a larger one of diameter 1,300 light-years, which has already been observed by ground-based telescopes, and a previously unseen ring of diameter 260 light-years.

在圆规座的漩涡星系中的大部分气体都与两个具体的"环"有密切的联系。那个较大的，直径大约有1，300光年，它已经被地基望远镜观测到了。而先前，我们没有观测到的那个小"环"，直径大约有260光年。

This paper analyzes the Michelson interference and presents a method to measure circle diameter of interfering images using image sensor and computer.

通过对迈克耳孙干涉图样的研究，提出了应用图像传感器和计算机测量圆环直径的方法，该方法也适用于牛顿环等光学实验的图样的分析。

PDCA can be an independent circle to solve an independent problem.

PDCA可能是一个独立的环，如解决一个独立的问题，当这个问题解决了，那么这个环也随着消失了；也可能是一个持续改进的过程，即螺旋上升过程，即当这个问题没有解决或已经解决了但又有新的问题发现，又会根据这个问题，进行下一个PDC循环。

With the interpolation principle of high precision multi-layered neural network, a closed-loop control method for swing-up process of circular rail inversed pendulum is investigated based on the optimized open-loop control law.

摘要在圆轨倒立摆摆起过程开环控制律优化算法的基础上，应用高精度多层人工神经网络插值原理，研究了摆起过程的闭环控制方法。

The parabolic mirror reflected a circular ranging ring which was adjustable to various diameters representing various wingspans.

抛物面镜反射一个圆形的测距环，测距环可以依据不同的翼展来调节不同的直径。

The segment arrangement on circular curves has proven theoretical support;the segment arrangement on transition curves,however,has no theoretical support and is usually executed by means of VMT systems equipped on shield machines.

对于圆曲线的管片排版已有了相对较为成熟的理论，而缓和曲线上的管片排版以往通常是根据盾构机VMT来选择，没有成型的理论支持，为此，结合测量理论和弯环管片的实际，探索出在缓和曲线上准确选择弯环管片理论排版的方法。

The segment arrangement on circular curves has proven theoretical support; the segment arrangement on transition curves, however, has no theoretical support and is usually executed by means of VMT systems equipped on shield machines. On basis of the relevant survey theories and the actual conditions of the turning rings, the author probes into the segment arrangement on transition curves in the paper.

对于圆曲线的管片排版已有了相对较为成熟的理论，而缓和曲线上的管片排版以往通常是根据盾构机VMT来选择，没有成型的理论支持，为此，结合测量理论和弯环管片的实际，探索出在缓和曲线上准确选择弯环管片理论排版的方法。

Due to the coupling of every Zernike circular polynomial in the annular field, the SEIDEL coefficients solved by wavefront fitting with circular polynomial for annular pupils with big central obscuration would have larger errors.

由于Zernike圆多项式各项在环域上的交叉耦合，对于具有大中心遮拦的环孔径波面采用圆多项式拟合求解SEIDEL像差系数存在较大误差。

Circularization could provide for translational regulation.

环化为调控蛋白质翻译提供了一种手段，调节蛋白结合在5'端与3'端的非翻译区，促进或破坏环化。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。