四价

At diakinesis, 0.2 tetravalents, 0.05 hexavalents and 0.05 octovalents per pollen mother cell were detected, which was absent in cultivated cucumber. In 30% PMCs, crossed chromosomes occurred at diakinesis.

在减数分裂终变期，平均每个花粉母细胞有0.2个四价体、0.05个六价体和0.05个八价体，约30%的花粉母细胞中存在拉十字的染色体。

The results indicate that the Sn on the catalyst is present in tetravalence, in alloy with platinum, and in divalence.

结果表明该催化剂中的锡主要有正四价锡、铂-锡合金和正二价锡。

Barley seeds were irradiated with five different doses of 60 Co-γ ray.There were many kinds of chromosome aberration in pollen mother cells,such as bridge,laggards in anaphase I and anaphase II,asymmetrical division in anaphase I and asynchronous division in anaphase II,ring quadrivalent in metaphase I,three pole division and micro-nuclei in telophase I,micro-nuclei in tetrad and some micro-nucleus separates from the tetrad to form polyad.

大麦种子经5种不同剂量γ射线辐照后， M1植株的花粉母细胞出现多种染色体畸变类型，例如后Ⅰ、后Ⅱ中出现桥、落后，后Ⅰ中出现不对称分裂，后Ⅱ中出现不同步分裂，中期Ⅰ出现环状四价体，末期Ⅰ中有三极分裂和微核，四分体中出现微核且有的微核独立于四分体，从而形成多分体。

The free hydroxyl radical of greater activity produced in the catalytic ozonization of V is the essence of the catalytic system; and the formed V also contributed greatly to the removal of chemical oxygen demand.

结果表明，催化体系的本质是催化剂中的四价钒催化臭氧分解生成了活性更高的羟基自由基，所生成的五价钒对体系化学耗氧量的去除也有很大的贡献（近10%）。

Paper publishes materials that are used by anlistatig is a tetravalent salt toxicchemical on the surface of the paper, in low humidities quadrivalent salt water from the air, to reduce the material surface resistance.

纸类承印质料所用的抗静电剂是一栽四价盐的冻学品涂在纸暗不天上后，在矮湿度下四价盐从氛围洋汲取水分，使堵住质料暗不天的电阻减小。

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。

Morphologically, the two hexaploids are characterized by the general gigantic appearance, diagnostic of the enhancing growth in horizontal direction of such organs as leaves, stems, various compone...

它们在减数分裂时的单价体数目比三倍体显著地减少了，但另外却有少量三价体和四价体出现。

The cytogenetics of interspecific hybrids among the four cultivated cotton species were studied in this paper and results are as follows: The diploid interspecific hybrid (G. arboreum×G. herbacium) F〓 had a four-chromosome-ring at the meiotic metakinesis. The synapses of tetraploid hybrid (G. hirsutum ×G. barbadense) F〓 was found to be regular, which mainly formed bivalents, sometimes some univalents, multivalents and chromosome bridge.

四个栽培棉种间杂交种F〓的细胞学观察结果表明，F〓减数分裂中期Ⅰ，形成一个环状四价体，直接证明了亚洲棉与草棉之间存在一对相互易位；F〓减数分裂中期Ⅰ联会基本正常，主要形成二价体，偶尔出现一些单价体和多价体，以及染色体桥。

In meiosis of pollen mother cells of the tetraploids and the hexaploids, only bivalents were observed in most of the populations, although in several populations or individuals a few univalents or tetravalents appeared. In the hexaploids, hexavalents were not observed.

四倍体和六倍体的花粉母细胞减数分裂染色体构型在大多数居群都为二价体(四倍体中30个二价体，六倍体中45个二价体)，少数居群或是个体除二价体为主外还出现单价体和四价体，六倍体类型没有出现六价体构型。

Through tests on the determination of interference from the sample color, not only is its interference eliminated but also the accuracy of the method improved.

培酸法适用于深色溶液分析，灵敏度和准确度较高，通常用于总钒的仲裁分析；但是该法只适用于测定总钒，四价钒与五价钒只能用其它方法测定，这样就会引入方法误差，使四价钒、五价钒与总钒不匹配。

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。