二酸价的

In acid and alkali soil, there are mainly indissoluble bivalent or trivalent phosphates, which cannot be utilized by plants.

在酸碱性土壤中，磷主要以植物难以吸收利用的难溶性二价或三价阳离子的形式存在。

A compound derived from ammonia and containing the bivalent NH group combined with a bivalent nonacid group.

亚胺源自氨的一种化合物，含有与一个二价非酸基结合的氨基

Based on the biochemical analysis of the two proteins in vitro, the results of yeast two-hybrid experiment and protein-interaction in both wild type cells and C48 strain, we conclude HetR can form a homodimer through the Cys48 residue. We also show that the dimerization is required for heterocyst differentiation.

基于体外两种蛋白的性质比较和酵母双杂交的结果，并结合相应蓝细菌野生型和突变株C48A中HetR蛋白性质的体内研究表明：HetR蛋白可以通过第48位半胱氨酸残基形成共价结合的同源二聚体，该同源二聚体是异型胞正常分化所必需的。

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。

The most commonly used method for the covalent binding of biomolecules onto 1-D nanostructures is through the diimide-activated amidation of carboxylic acid terminated nanostructures.

最常用的方法是通过端羧酸基纳米结构的二酰亚胺活化氨基化合物来进行生物分子与1-D纳米结构的共价结合。

In part one, the reactions of some active fluorine-containing compounds such as 2, 2-dihydropolyfluoroalkanoic acids and ethyl 2-hydropolyfluoroalkenoates were studied and various fluorine-containing heterocyclic compounds were synthesized. Using 2, 2-dihydropolyfluoroalkanoic acids as the starting material, 4-fluoroalkyl quinolin-2-ols, 2- [ -1-hydropolyfluoro-1-alkenyl] -4H-3, 1-benzoxazin-4-ones, 1-aryl -4, 9-dihydro-3-fluoro-alkyl-1H-pyrazo [3, 4-b] quinolin-4-ones, 5-fluoroalkyl-12H-quin olino [2, 1-b] quinazolin-12-ones, 4-fluoroalkyl-1, 3-dihydro-1, 5-benzodiazepin-2-ones and 4-fluoroalkyl-2H-pyrido [1, 2-a] pyrimidin-2-ones were synthesized through its condensation reaction with anilines, anthranilic acid, N'-aryl-o-aminobenzamides, o-nitro aniline, o-amino pyridine and their derivatives and the subsequent transformations. 5-Fluoroalkyl isoxazolidines, 3-fluoro-3-fluoroalkylisoxazolidino [4, 3-c] quinolin-4-ones, 3-fluoroalkylisoxazolino [4, 3-c] quinolin-4-ones and 2-aryl-3per fluoroacylindoles were synthesized by inter-and intramolecular 1, 3-dipolar cycloaddition of fluorine-containing olefins and nitrones.

第二部分，我们研究了α，α-二氟苄基卤类化合物的亚磺化脱卤反应、产物的转化及全氟烷基亚磺酸盐与芳环化合物的全氟烷基化反应，发现全氟苄基碘或溴及α，α一二氟苄基溴在保险粉等亚磺化脱卤试剂引发下可生成相应的亚磺酸盐；全氟苄基亚磺酸盐与氯气或溴反应可生成全氟苄基磺酰氯或磺酰溴；在烯烃存在下，全氟苄基碘则与烯烃发生加成反应，生成相应的1：1加成产物；在三价醋酸锰的作用下，部分芳香化合物如茴香醚，二甲氧基苯，吡啶，喹啉等可以和过量的全氟烷基亚磺酸盐发生双全氟烷基化反应，反应表现出一定的区域选择性，产率良好。

Any of several esters, other than the ethyl ester, of carbamic acid .

亚胺源自氨的一种化合物，含有与一个二价非酸基结合的氨基

In order to mimic this repair process of apoenzyme, we synthesized two model compounds, in which tryptophan and/or tyrosine was covalently linked to cyclobutane thymine dimer, and measured the splitting quantum yield of dimer under 295 nm light. By investigating the photosensitized splitting properties of the dimer, some new insights into the intramolecular electron-transfer process were gained.

为了模拟酶蛋白的这一修复过程，合成了色氨酸和/或酪氨酸与胸腺嘧啶二聚体共价连接的化合物，作为酶-底物复合物的模型，研究了它们在295 nm光照射下氨基酸残基光敏化二聚体裂解的性质，测定了二聚体裂解量子产率，获得一些新的结果并对其进行了分析。

The three tetranuclear copper complexes are structurally analogous and they all consist of a pair of [Cu22]+ or [Cu22]+ fragments bridged by a deprotonated dicarboxylate into dumbbell-shaped, neutral, tetranuclear molecules.

三个四核混合价铜化合物具有相似的分子结构，它们由一对[Cu22]+或 [Cu22]+碎片和一个架桥的二羧酸配体组成中性的四核的哑铃型结构。

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。