两对称

Relating to, designating, or characterized by a tail fin having two symmetrical lobes extending from the end of the vertebral column, as in most bony fishes.

正尾的，等形的与一种尾鳍有关的或以其为特点的，这种尾鳍有对称的两叶从脊椎一头延伸出来，大多数多骨鱼均如是

A new two frequency laser alignment system is developed which consists of two Wollaston prisms with the same structure. One is for measurement; another for compensation.

介绍了一种新型自适应双频激光准直系统，该系统利用了两个完全对称的渥拉斯顿棱镜，一个作为测量元件，另一个作为补偿元件。

Using the Boussinesq approximation equations for meso-scale disturbances in zonally linear and non-linear shear flows a study is undertaken of the unstable features and wave properties of two typical meso-scale unstable disturbances i. e. symmetric and transversal instabilities.

使用纬向线性以及非线性切变基流下中尺度扰动的Boussinesq近似方程组，讨论了两种典型的中尺度扰动发生对称不稳定或者横波不稳定时，其不稳定的一些特征以及扰动的波动性质。

In the light of sea regions where El Nino events occurred, ENSO events are separated into two categories- the equatorial Pacific warming and the mid-Pacific counterpart, which exert influence directly on a WPSH through a Walker circulation asymmetrical zonally, in such a way that there an El Nino year- a weak Walker circulation- a more intense and southward WPSH-late onset of South-China sea summer monsoon - a more southward and vigorous summer WPSH- the mid-lower valleys of the Yangtze river hit by flood.

上述两种类型的ENSO均可直接通过纬向非对称的Walker环流直接对西太平洋副高产生影响，表现为：El Nino年—Walker环流弱—西太平洋副高偏强、偏南—南海夏季风爆发晚-夏季西太平洋副高偏南、偏强—长江中下游涝。

This dissertation focused on two types of reactions, oxidative allylation of 1, 3-dicarbonyl compounds and ring-opening allylation of epoxides.

我们重点考察了两类反应：1， 3－二羰基类化合物的不对称烯丙基化反应和环氧化合物的开环烯丙基化反应。

The asymmetric ring-opening aminolysis of meso-epoxides represents one of the most important reactions in organic synthesis,giving rise to enantio-enriched aminoalcohol products with two chiral centers.

中文摘要：胺类对内消旋环氧化合物的不对称开环是一类重要的反应，反应生成两个手性中心的氨基醇化合物在有机合成中有着重要的应用。

The diurnal variation curves of Pn among different types of pear cultivars are different, and there are two types, single-apex curve and anisomerous double-apex curve.

不同类型梨品种叶片Pn日变化曲线不同，有单峰型和不对称双峰型两类，新鸭梨及黄冠Pn曲线呈单峰型，清香、红巴梨和库尔勒香梨的Pn日变化曲线为双峰型

The short shoot differentiation came from the lateral buds among the bud scales, in the initial stage, the lateral buds elongating, and then differentiating two "anisomerous"(one was small, the other was big) needle primordia in the elongating courses; the big one differentiating once more, and formed three needle primordia.

短枝的发育来源于长枝上芽鳞间的侧芽，在发育的初期，侧芽进行伸长生长，在伸长生长的过程中首先分化出一大一小&不对称&的两个针叶原基，大的叶原基进一步分化，形成三个针叶原基。

The coordination polyhedron around Ce3＋ is a distorted square antiprism, and the two independent molecules are connected by π-π stacking interactions to form a noncentrosymmetric dimer.

中心Ce3＋的配位多面体为变形双帽四方反棱柱，两个分子之间以π-π堆积连接，生成一个非中心对称的二聚体。

In order to develop an useful synthestic process, we have synthesized amides with various substitutents. The isoquinoline skeleton was constructed through Bischler-Napieralski reaction, followed by asymmetric reduction of the imine intermediates with a Ru complex to form the only chiral center. Finally, we connected the two phenyl groups by Heck reaction and effectively obtained optically active aporphine alkaloids.

为了发展一套实用的合成方法，我们首先制备於苯环上具有不同种取代基的苯乙醯胺，接著透过Bischler-Napieralski反应进行分子内合环，并利用钌金属对亚胺中间体进行不对称的还原反应，建立出产物中唯一的光学活性中心，最后再利用Heck反应连结两个苯环，就可以顺利得到具有光学选择性的阿朴吩类天然物。

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％。