溶剂超临界CO2雾化萃取法制备乙基纤维素微粒的研究

通过溶剂超临界CO2雾化萃取法制得了乙基纤维素微粒．研究了溶液喷口流速、溶液浓度、温度、压力对颗粒粒径及其粒径分布的影响．结果表明，改变工艺参数，可在较大范围内调控微粒大小，所得微粒平均粒径为0．64～10．83μm．随着温度和溶液浓度的增加，颗粒粒径及其粒径分布增加；随着压力和溶液喷口流速的增加，颗粒粒径及其粒径分布减小．

Study on micronization of ethyl cellulose by areosol solvent extraction system using supercritical CO2

The research of linguistics had been within the limit of morpheme, vocabulary, sentence and the meaning of sentence expression during a long period of time. The study above unit of sentences has been once considered as the problems in the fields of rhetoric and literature. In recent years, Western linguists have been made systematical research on sentence, style, register, text and the internal relationship of text structure. However, it is not enough to do that only on the connection of sentence and text for language study. In fact, perfect articles consist of some paragraphs which are constructed by numbers of sentence groups. This paper mainly analyses the formation and function of English sentence groups in text by using the theory of linguists.