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- This paper reports studies of IR spectra of a series of macrocyclic polyethers and their substitution derivatives and the information of steric effect in the molecule. 内酯冠醚化合物的红外光谱研究报道很少,特别是随醚环的扩大和醚环骨架上不同取代基的引入所引起的中红外光谱的变化尚缺乏研究。
- We use saccharin in substitution for sugar. 我们用糖精代替糖。
- An organic derivative, such as coal or petroleum. 有机衍生物一种有机衍生物，如煤或石油
- Methods: The UV-VIS detect method was adopted to test the spectra of tetraphenylporphyrine and its substitutive derivatives under different conditions. 方法:采用紫外可见分析法测定不同条件下的吸收光谱。
- substitution derivative 取代衍生物
- A facile synthesis of heterocycle substituted derivatives of cyclopropanes by the reaction of telluronium salts with heterocycle substituted chalcones is reported. 本文报道了由碲盐和杂环取代查尔酮反应合成杂环取代环丙烷衍生物的简便方法。
- The hexagonal ring structure in the benzene molecule, C ' H ' , and its substitutional derivatives, each vertex of which is occupied and distinguished by a carbon atom. 苯环：苯分子中的六角环形结构及其置换派生物，C'H'，每个顶点被一个碳原子占据或通过一个碳原子加以区别
- An acyl derivative of hydrazine. 酰肼一种由肼衍生而来的酰
- A cathodic reduction potential shift of L substituted derivatives vs the parent clusters showed that coordination of L to Co resulted in the increase of charge density on CCo_3 unit, wkioh made the cluster hard to reduce. 取代簇合物的还原电势相对于母体簇合物的负移表明P的配位增大了CCo_3上的电荷密度,导致簇合物难被还原。
- Substitution of a new obligation for an old one. 更新新契约对旧契约的替代
- A mark used as a superscript to indicate the first derivative of a variable. 撇号置于右上角的符号，用以标明变量的第一个导数
- Ab initio calculation with STO-3G basis sets and DFP geometry optimization method were used to study conformation stability of pentadienyl anion and its methyl substituted derivatives. 用STO-3G基组的从头计算和DFP梯度几何优化方法对戊二烯负离子(C_5H_7~-)及其甲基取代衍生物进行了骨架优化.
- The derivative of the step is the impulse. 阶梯的导数就是脉冲。
- The substitution of coal for oil is desirable. 以煤代替石油是可取的。
- Methods of structure modification of lead-compound piracetam,including acetamide side chain modified derivates,ring substituted derivates,and derivates lacking acetamide side chain,are summarized. 综述了对先导化合物吡拉西坦进行结构修饰的方法:乙酰胺侧链修饰衍生物、环修饰衍生物和非乙酰胺侧链衍生物法,并介绍了合成吡拉西坦类促智药的方法及其优缺点。
- A derivative is defined by a limiting process. 导数是通过一个极限过程加以规定的。
- A substitution, an exchange, or an interchange. 交换代替、交换或互换
- They spoke a derivative of the Malay language. 他们说一种从马来语派生的语言。
- A highly derivative prose style. 毫无创意的散文风格
- The substitution of the phoneme/l/ for/r/ . 错把1音发成r。
