查询词典 bivalent

Due to the ability of the bivalent magnesium cation to form stable chelate complexes with carbonyl compounds,magnesium methylate for example is used as a selective carbonyl condensing agent. Three synthesis routes was proposed based on literatures and comprehensive comparison with other ways. First,Magnesium methylate is prepared by reacting magnesium metal with dry methanol.The magnesium salts of"higher"primary alcohols,i.e.alcohols with ≥ 2 carbon atoms,do not react directly with pure alcohols under normal conditions.In fact catalysts are required to set the reaction in motion and the preparation is performed under pressure at the higher temperatures.

一、直接合成法：本文将镁与无水甲醇直接反应制得甲醇镁；"更高级"的醇（比如C≥ 2的醇）在无催化剂的条件下无法直接和镁进行反应，本文以CCl4为催化剂将无水乙醇与镁直接反应制得乙醇镁，但是以原甲酸三乙酯为催化剂无水乙醇与镁无法反应；不论是以CCl4为催化剂还是以原甲酸三乙酯为催化剂，丙醇均无法与镁直接反应。

Due to the ability of the bivalent magnesium cation to form stable chelate complexes with carbonyl compounds,magnesium methylate for example is used as a selective carbonyl condensing agent.Three synthesis routes was proposed based on literatures and comprehensive comparison with other ways.First,Magnesium methylate is prepared by reacting magnesium metal with dry methanol.The magnesium salts of higherprimary alcohols,i.e.alcohols with ≥ 2 carbon atoms,do not react directly with pure alcohols under normal conditions.In fact catalysts are required to set the reaction in motion and the preparation is performed under pressure at the higher temperatures.

一、直接合成法：本文将镁与无水甲醇直接反应制得甲醇镁；"更高级"的醇(比如C≥2的醇)在无催化剂的条件下无法直接和镁进行反应，本文以CCl_4为催化剂将无水乙醇与镁直接反应制得乙醇镁，但是以原甲酸三乙酯为催化剂无水乙醇与镁无法反应；不论是以CCl_4为催化剂还是以原甲酸三乙酯为催化剂，丙醇均无法与镁直接反应。

We also analysed the SCs of 30 spermatocytes at pachytenes, showing 20 autosomal bivalents, a quadrivalent 11; 18 and a sexual bivalent.

病例4为受孕浪费、生育过一例具有21三体特征患儿的患者，体细胞染色体分析表明，其核型为45，XY，-21，-21，+rob（21q；21q）。

Results showed that the PMC meiosis of autotetraploid was similar to the diploid except some particularities. In metaphase Ⅰ, multivalent, quadrivalent, trivalent, bivalent and univalent were observed and some of the chromosomes were found not to rank on the metaphase plate and so did in metaphase Ⅱ cells. In anaphase Ⅰ and anaphase Ⅱ cells, there were lagging chromosomes, chromosome bridge and fragment. During anaphase Ⅱ and telophase Ⅱ, chromosome segregation was not synchronous or equal. At tetrad stage, dyad, triad, tetrad with micronucleus and polyad appeared.

结果表明，同源四倍体花粉母细胞减数分裂过程与二倍体相比，中期Ⅰ染色体构型复杂，有多价体、四价体、三价体、二价体和单价体；中期Ⅰ及中期Ⅱ有部分染色体没有排列在赤道板上；后期Ⅰ及后期Ⅱ出现落后染色体、染色体桥及断片；后期Ⅱ和末期Ⅱ有染色体不同步分离及不等分裂的现象；四分体时期还出现二分体、三分体、含微核的异常四分体及多分体。

After it was adjusted with ammonia until the test paper turned purple,in subacid medium of pH 6～7 ammonium acetate buffered solution,bivalent nickel was precipitated quantificationally by dimethylglyoxime.

试样以稀硝酸溶解高氯酸冒烟后，酒石酸掩蔽剂将铁等干扰元素配位掩蔽，以氨水调节至刚果红试纸呈紫色后，在pH6～7的乙酸铵缓冲溶液微酸性介质中，二价镍定量地被丁二酮肟沉淀。

Aside from the code model of translation, this thesis brings out two basic models of inferential translation in the light that there exist two types of translational constituents: univalent and bivalent ones.

在关联理论的框架中，翻译被看作是交际的一种特例。译者具有双重身份，在不违背最佳关联的条件下，译者起着中介者的作用。

At zygotene,t he SC formation initiated at multiple sites in each bivalent but the regions nea r telomeres were preferred.SCs were shortened with development of SCs.Initiation of new SC and extension of existing SC occured simultaneously,and pairing in di fferent bivalents of a nucleus was not synchronised.

结果表明，小麦SC以多点式起始方式于偶线期开始形成；随SC的发育，新的SC形成和已有SC片断的延伸并存；此外，在同一核内不同二价体之间，染色体配对和SC形成并不同步；SC成熟于粗线期，而以破碎方式解体，消失于双线期。

Key words: chicken; infectious bursal disease virus; variant; bivalent attenuated vaccine; immunogenicity

关 键 词：鸡；传染性法氏囊病病毒；变异株；二价弱毒疫苗；免疫原性

In particular, the documentation of rapid and extensive non-Mendelian genetic and epigenetic changes that often accompany nascent polyploidy is revealing: the resulting non-additive and novel gene expression at global, regional and local levels, and timely restoration of meiotic chromosomal behavior towards bivalent pairing and disomic inheritance may ensure rapid establishment and stabilization as well as its long-term evolutionary success.

特别是，所发现的在多倍体形成初期，快速且大量产生的非孟德尔遗传变异和表观遗传变异为相关机理的探讨提供了重要的启示。不同尺度上的基因非加性表达以及染色体二价体联会和二体遗传方式的快速建立可能对新形成多倍体的早期稳定和长期进化优势都具有重要意义。

The gelable fiber is cross-linked by a bivalent or multivalent basic cross-linking agent, thereby cross-linking the composite fiber.

胶凝纤维通过二价或多价碱性交联剂交联，从而使复合纤维交联。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。