查询词典 asymmetric

Three chiral phosphorus ligands were prepared using anisole as the startingat material.Their applications in the asymmetric hydroformylation and asymmetric conjug ed addition of diethylzinc to enones were investigated.

以苯甲醚为原料，合成了三种新的手性含磷配体，考察了三种配体在不对称氢甲酰化反应和ZnEt2对环己烯酮的不对称共轭加成反应中的应用。

It is inextricably linked with existing substance, which is asymmetric; it also asymmetric with rich system of science itself and infinity expansibility.

这和存在的事物，具有千丝万缕的联系，不对称；也和科学本身丰富的体系、无限的可发展性，不对称。

Finally, in order to put a DSTATCOM into normal operation under serious asymmetric supply voltages of power system, asymmetric control based on the

理论研究和仿真结果验证了所给出的算法正确性与可行性。

The mechanism and dynamic model of ASVG is introduced in this article at first. Then the authors point to the problems of running and control of ASVG under asymmetric conditions of power system, and put forward the asymmetric expert PID control law. Under the experimental condition of 10%negative voltage, the simulated results are given.

论述了ASVG的工作机理和在系统电压对称时的动态数学模型，并针对系统电压不对称时ASVG的运行与控制问题，分析了系统电压不对称时的被控对象模型，提出了恒电压不对称专家PID控制方法，给出了系统有15%的负序电压时的仿真结果。

Asymmetric autocatalysis occurs when a chiral product operates as an asymmetric catalyst for its own production.

不对称自催化反应是指由不对称反应生成的手性产物自身作为催化剂的反应过程。

In the asymmetric flow field of typhoon A,the azimuthal phase of asymmetric gyres due to the linear beta effect is opposite to that of .

在台风A的非对称流场中，由台风A的线性β效应产生的非对称涡旋的方位相位与由台风B形成的非对称涡旋的方位相位相反。

The reported organocatalyst for asymmetric Mannich reaction include proline derivatives, chiral phosphoric acids, chiralurea derivatives, cinchona alkaloids and so on, which can catalyze the asymmetric Mannich reaction with high catalytic activity and excellent enantiselectivity.

本文评述了各类有机催化剂在有机催化不对称Mannich 反应中的应用研究进展，以及不对称诱导反应的机理、催化剂分子结构及反应条件对其催化活性和不对称诱导作用的影响。

Tetraploid embryos could be produced by electrofusion at the stage of two-cell embryos, which could develop to blastocysts followed by fusion of cytoplasm and nucleus and cleavage in vitro. During the fusion of cytoplasm, the DNA methylation levels of the fused embryos are as high as these of two-cell diploid embryos in vivo Then the embryos are rapidly demethylated when the nucleus begin to fuse, resulting in the lowest DNA methylation levels when the nucleus are fused completely. After that, the DNA methylation levels of the fused embryos are gradually increased until the morula stage. However, whereas an asymmetric distribution of DNA methylation is established in vivo-derived blastocysts with a higher methylation level in the inner cell mass than that in the trophectoderm, we can not detect the asymmetric distribution in most in vitro-derived tetraploid blastocysts.

结果表明：利用电融合方法制备的小鼠四倍体胚胎在体外培养体系中经历细胞质融合、细胞核融合及细胞继续分裂发育直到囊胚期的过程，在细胞质融合的时候胚胎卵裂球同体内体外培养二倍体胚胎一样，呈现高度甲基化状态；在细胞核开始融合的时候，甲基化水平急速下降，在细胞核完全融合的时候甲基化水平达到最低点；随着胚胎继续分裂，胚胎甲基化水平逐渐增加，在桑葚胚期甲基化水平最高；但是囊胚期四倍体胚胎内细胞团同滋养层细胞甲基化荧光信号没有差别，这与体内体外培养二倍体囊胚内细胞团细胞甲基化荧光强度高于滋养层细胞甲基化荧光强度不同。

Tetraploid embryos could be produced by electrofusion at the stage of two-cell embryos, which could develop to blastocysts followed by fusion of cyto-plasm and nucleus and cleavage in vitro. During the fusion of cytoplasm, the DNA methylation levels of the fused embryos are as high as these of two-cell diploid embryos in vivo Then the embryos are rapidly demethylated when the nucleus begin to fuse, resulting in the lowest DNA methylation levels when the nucleus are fused completely. After that, the DNA methy-lation levels of the fused embryos are gradually increased until the morula stage. However, whereas an asymmetric distribu-tion of DNA methylation is established in vivo-derived blastocysts with a higher methylation level in the inner cell mass than that in the trophectoderm, we can not detect the asymmetric distribution in most in vitro-derived tetraploid blastocysts.

结果表明：利用电融合方法制备的小鼠四倍体胚胎在体外培养体系中经历细胞质融合、细胞核融合及细胞继续分裂发育直到囊胚期的过程，在细胞质融合的时候胚胎卵裂球同体内体外培养二倍体胚胎一样，呈现高度甲基化状态；在细胞核开始融合的时候，甲基化水平急速下降，在细胞核完全融合的时候甲基化水平达到最低点；随着胚胎继续分裂，胚胎甲基化水平逐渐增加，在桑葚胚期甲基化水平最高；但是囊胚期四倍体胚胎内细胞团同滋养层细胞甲基化荧光信号没有差别，这与体内体外培养二倍体囊胚内细胞团细胞甲基化荧光强度高于滋养层细胞甲基化荧光强度不同。

Tetraploid embryos could be produced by electrofusion at the stage of two-cell embryos, which could develop to blastcysts fellowed by fusion of cytoplasm and nucleus and cleavage in vitro.After fusion of cytoplasm, the DNA methylation levels of the fused embryos was very high as well as two-cell diploid embryos in vivo.Then the embryos was rapiddly demethylated when the nucleus begin to fuse, resulting the lowest DNA methylation levels when the nucleus fused completely.After that, the DNA methylation levels of fused embryos were gradually increased until the blastocysts stage.However, whereas an asymmetric distribution of DNA methylation was established in an vivo-derived blastocysts with a higher methylation level in the inner cell mass than in the trophectoderm, in most vitro-derived tetraploid blastocysts, we can not detect the asymmetric distribution.

结果表明：利用电融合方法制备的小鼠四倍体胚胎在体外培养体系中经历细胞质融合、细胞核融合及细胞继续分裂发育直到囊胚期的过程，在细胞质融合的时候胚胎卵裂球同体内体外培养二倍体胚胎一样，呈现高度甲基化状态；在细胞核开始融合的时候，甲基化水平急速下降，在细胞核完全融合的时候甲基化水平达到最低点；随着胚胎继续分裂，胚胎甲基化水平逐渐增加，在囊胚期甲基化水平最高；但是囊胚期四倍体胚胎内细胞团同滋养层细胞甲基化荧光信号没有差别，这与体内体外培养二倍体囊胚内细胞团细胞甲基化荧光强度高于滋养层细胞甲基化荧光强度不同。

I am accused of being overreligious," she said in her quiet, frank manner,"but that does not prevent me thinking the children very cruel who obstinately commit such suicide.""

客人们在卡罗利娜·埃凯家里，举止就文雅一些，因为卡罗利娜的母亲治家很严厉。

Designed by French fashion house Herm è s, this elegant uniform was manufactured in our home, Hong Kong, and was the first without a hat.

由著名品牌 Herm è s 设计，这件高贵的制服是香港本土制造，是我们第一套不配帽子的制服。