四碱的

In DNA, four different bases are found. Two of these, adenine and guanine , are double-ring structures called purines.

在DNA中，有四种不同的碱基，其中的两个为腺嘌呤和鸟嘌呤，即称为嘌呤的双环结构。

These can attach themselves to cytosine, one of the four chemical bases that form the "letters" of the genetic code.

它们可以附在胞核嘧啶上，胞核嘧啶是组成基因代码的"字母"的四种碱基数之一，帮助调控转录的过程。

China is the big country of production and consumption of battery, the annual production of the battery is above 15 billion, accounting for 1/4 of the whole world, 96% among them is zinc manganese dry cell and alkali manganese dry cell.

中国是电池生产和消费大国，电池的年产量在150亿只以上，占全世界的四分之一，其中96%的为锌锰干电池和碱锰干电池。

The benzylpiperidine derivatives show high activity of inhbiting against AChE in vitro, some of them are even more potent than -Hup A and Tacrine.

苄基哌啶类衍生物的胆碱酯酶活性发现，其与四氢吖啶的衍生物对AChE的抑制活性超过石杉碱甲和Tacrine。

Using the hanging drop method, good crystals of maltotetraose-forming amylase isolated from culture of Alcaligenes sp have been grown. Diffraction density data to 2.7? resolution were collected on a Mar Research Image Plate Detector System.

用悬滴汽相扩散法生长了从产碱菌中分离纯化得到的麦芽四糖淀粉酶的晶体，并在MarRe search面探测器上收集了一套2.7埃分辨率的衍射强度数据。

E. The DNA four kind of azotic basic group proportion has the unusual regularity, in each kind of organism DNA A≈T C≈G adds the Cuff principle.

e。 DNA的四种含氮碱基比例具有奇特的规律性，每一种生物体DNA中 A≈T C≈G 加卡夫法则。

The invention discloses a method for preparing novel nanometer TiO2 optical catalyst material, comprising that (1) preparing gel solution of modified lanthanide series that mixing butyl titanate, alcohol solvent, azotic acid, polyvinyl alcohol and lanthanide element,(2) using alkali liquid to treat the quartz fiber leaked from side wall,(3) using drawing membrane and high-temperature sintering to form modified TiO2 optical catalyst material on the surface of quartz fiber.

本发明公开了一种制备新型纳米TiO2光催化材料的方法，包括(1)配置镧系元素改性的溶胶溶液：将钛酸四丁酯、醇类溶剂、硝酸、聚乙烯醇和镧系元素的盐类混合搅拌；(2)利用碱液对侧壁漏光石英光纤进行处理；(3)通过提拉成膜和高温煅烧，在石英光纤表面形成改性TiO2光催化材料。

The spatial distribution pattern and dynamics of four species of dominant plants Hippuris vulgaris,Eleocharis valleculosa,Blysmus sinocompressus and Suaeda glauca in wetlands of the Qinghai Lake were studied by means of spatial distribution analyses.

应用种群生态空间分布的分析方法，研究了青海湖四种主要湿地植物：杉叶藻、槽杆荸荠、华扁穗莞、碱蓬的空间分布格局及其动态。

We can draw conclusions as follows:(1) The number of Suaeda linifolia seedlings in high salt soil is big,but the death rate of it is high and the death of seedlings is different at different time and space.

通过对上述四种植物的生物生态学特性的初步研究，我们发现：（1）盐渍化土壤上亚麻叶碱蓬幼苗死亡率很高，并且该幼苗夭亡现象存在时空异质性。

Salsa was a transmembrane protein with four transmembrane domains. Earlier experiments indicated the conserve glutamyl residue in the fourth transmembrane domains might participate in the proton translocating across the membranes.

盐地碱蓬液泡膜H〓-ATPase c亚基第四个跨膜区存在高度保守的谷氨酸残基，先前的研究表明此谷氨酸残基可能与H〓跨脂双层运输有关。

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。