双重取代

Structure and morphology of the starch and CMS was characterized by means of IR and SEM, and investigated the effect of synthesis factors on solution transparency of the CMS, having been realized that the solution transparency of CMS was influenced by DS and evenness of etherization.

用红外光谱和扫描电镜对原淀粉、CMS的结构及形貌进行表征，并探讨了合成因素对其溶液透明性的影响，得知CMS糊液透明度受取代度及醚化均匀度双重因素影响。

Planck constant and spin quantum number are calculated by the spacing of the twin line.These have high precision compared with theory value. sodium atomic spectra ; fine structure constant α; spin quantum number s

文献[2]用双光栅单色仪取代平面光栅摄谱仪研究钠原子光谱，能明显观察到谱线双重结构不同成分间的强度比

The product can replace the traditional putty scraping greasy base powder used, whilethe dual effect of topcoat.

该产品既可以取代传统腻子粉打底刮腻使用，又能达到滚刷面涂面漆的双重效果。

The reaction of cyclic b-keto esters with CF3CO2ZnCH2I provides the corresponding ring-expanded products with the advantage of mild condition in moderate to good yields. A simple and efficient procedure has been developed for a variety of 1,3-diketones converted into the corresponding 1,4-diketones and trans-1,2-disubstituted cyclopropanols in high yields. In conclusion, this new type of organozinc reagents has been developed for many useful reaction in organic synthesis.

利用有机锌试剂所具有的双重特性，在新型的Baylis-Hillman反应中，可以直接与炔基酮和醛反应一锅制得多官能团的三取代的顺式烯；在b-酮酯化合物的扩环反应中，取得了重要进展，得到了增加一个碳的扩环产物，&一步法&合成，反应条件温和、环境友好；在1，3-二酮分子中成功地插入1个碳，合成出1，4-二酮和环丙醇，为现代有机合成提供了新的合成方法，具有良好的应用前景。

Since the last days of the Middle Ages the creation of an intellectual aristocracy has been, so to say, the spiritual purpose of civilization side by side with its material purpose of supplanting the aristocracy of status by the aristocracy of wealth.

中世纪末开始，在文明所包含的精神目的、物质目的的双重作用下，精神贵族出现了，凭物质财富而赢得特权的人取代了传统上具有显赫地位的贵族。

Neither the killing of Mr Zarqawi nor any breakthrough on the political front will stop the insurgency and the fratricidal murders in their tracks.

在对危险的南部地区访问时，他斥责什叶派民兵领导人对中央集权的挑衅行为。

In fact,I've got him on the satellite mobile right now.

实际上 我们已接通卫星可视电话了