可取代的

1H NMR spectroscopic analysis of aromatic protons combined with theoretical analysis of molecular structures proved the existence of two rotational isomers at 300 K, as well as a rapid interconversion equilibrium at 330 K for both compounds Ⅰ and Ⅱ. However, only one conformer exists for compound Ⅲ and puerarin containing 7-phenolic hydroxyl instead of propyl in A-ring as the case of compounds Ⅰ and Ⅱ. Based on UV-Visible absorption data of neutral and basic solutions, and on the density function calculations, the 7-phenolic hydroxyl group in A-ring was found to be more acidic than the 4'-phenolic hydroxyl group in B-ring. The mechanism of derivation reaction and the structure-reactivity relationship of puerarin as an antioxidant were further discussed.

其中7-丙基葛根素Ⅱ属于新型取代衍生物；变温1H NMR和理论计算结果表明，在300 K时，葛根素和4'-丙基葛根素以单一构型存在；而7，4'-二丙基葛根素和7-丙基葛根素则存在两种核磁可分辨的旋转异构体，当温度升至330 K时，两种异构体可以相互转化；通过对比分析葛根素及其衍生物脱质子产物的紫外可见吸收光谱并结合理论计算，确定了A环上7位酚羟基比B环上4'位酚羟基先脱去质子，并由此进一步阐明了葛根素衍生化反应机理以及在抗氧化作用中可能的活性位点和结构活性关系。

Partly as a consequence of the costliness of such negotiation ,rules of the road are developed.

部分由于这种谈判的高成本，道路交通规则得到发展。限速，交通信号，通过马路时的法律限制等，取代了可转让的个人权利。

Benzoxazine compounds are one kind of highly active protoporhyrinogen oxidase inhibitors. These compounds can effectively control both monocotyledon weeds and dicotyledon weeds at lower dosage. The action mechanism is similar to p-nitro-o-substituted diphenylethers. They can result weeds albinism and decolorization, which are very important albinism herbicide.

苯并噁嗪类化合物是一类高活性的原卟啉原氧化酶抑制剂，低剂量可有效地防除禾本科与阔叶杂草，其作用机理和对硝基邻位取代的二苯醚类似，它们造成白化或脱色，是白化除草剂中较重要的种类，其活性远超过二苯醚除草剂，是目前化学农药研究领域的热点。

As one of the three actual supervisory manners of arbition of the Chinese commercial affairs, the judicial supervision with its particular compulsion and implementation, has been the centrum of arbitrative supervisory system, which cant be replaced by the interior supervision or the industrial supervision.

而司法监督作为中国商事仲裁现行的三种监督方式之一，因其所独有的强制性和可执行性，成为内部监督和行业监督所不能取代的仲裁监督体系的中枢。

Therefore, butoxy in n_butanol can be adsorbed chemically on the surfaces of the tourmaline particles in the process of azeotropic distillation, which can effectively prevent the formation of liquid_bridge between the particles of tourmaline and avoid the hard aggregation in the drying process.

正丁醇中的丁氧基在共沸蒸馏过程中在电气石颗粒表面可取代羟基，产生化学吸附，能有效防止液桥的产生，阻止干燥过程中超细粉末的硬团聚。

Flowable polysilane polymers have been synthesized by sodium coupling of diorgano-dichlorosilanes with diphenylmethylchlorosilane in toluene.

采用具有不同有机取代基的二氯硅烷与甲基二苯基氯硅烷为原料，在甲苯中以金属钠共缩合的方法，合成了可流动的聚硅烷。

Under the changes being considered by the Government, the present system would be replaced by "rebuttable joint custody", where there would be a presumption that each child should spend equal time living with both parents, unless there are strong reasons against it.

根据政府正在考虑所做出的改变，现有体系将被&可反驳的共同监护&所取代；这意味着每一个孩子应该与父母有着同等生活时间的假定将会存在，除非反对理由十分强烈。

Low valent selenium and telluronium compounds have high reducing selectivity to be used to form carbon-hydrogen bonds as special reducing reagents.

低价硒、碲化合物具有良好的还原选择性，可用於多种碳-氢键的形成，碲叶立德和α-芳硒基取代的胂叶立德均可发生Wittig型反应，是形成碳-碳双键的重要方法。

SV-99 features a wooden two part stock with detachable skeletonized shoulder stock, which could be removed fro compact storage or replaced by pistol grip for operation in confined places.

的SV - 99采用了木制两个可拆卸的骷髅肩股票部分股票，这可能被删除来回节省储存空间，或操作手枪握在密闭的地方所取代。

Squashing Hamas's leaders does little long-term good unless there are credible moderate Palestinians to take their place.

粉碎哈马斯领导人长期而言并无多少益处，除非有可信赖的温和的巴勒斯坦人取代他们的地位。

In the United States, chronic alcoholism and hepatitis C are the most common ones.

在美国，慢性酒精中毒，肝炎是最常见的。

If you have any questions, you can contact me anytime.

如果有任何问题，你可以随时联系我。