An Analysis On The Thematic Progression Patterns Of English Mechanical Articles Introducing Latest Technology

English mechanical articles are those written by the staff working in mechanical industry to introduce mechanical knowledge or progression in this field. As a special category of text, a piece of English mechanical text has special composing convention. The convention is determined by the textual function of language. To realize this function, the theme progression is one of the most important methods. Based on the theme, rheme division in Halliday's system functional grammar and the theme, rheme progression patterns posed by Danes, this paper chooses at random 30 articles from the column of the technology feature in the U.K magazine of Machinery. By studying the theme progression(TP) pattern of the 30 articles, this paper tries to find the TP characteristics of the English mechanical articles which are of introductory type. It finds that the constant theme TP pattern and simple linear pattern are most frequently used in the 30 articles, which occur for 355 times and 374 times respectively, taking up altogether 59.1%; while the concentrated pattern and the alternative pattern are seldom used, which occur for 72 times and 12 times respectively, taking up only 6.77%. Basing on this, in the view of function and cognition, this paper also tries to reveal the internal causes which determine such TP characteristics. It shows that the TP pattern characteristics in English mechanical articles are determined by the communicative function and the cognitive process of human brain. In order to realize the communicative purpose of introducing new technologies, the author needs to organize the texts in a clear and logical way. The constant theme pattern and the simple linear pattern can highlight a topic and organize a logical text. Thus a successful communication can be achieved between the author and the reader. The cognitive process of human brain is a process from figure/trajector to ground/landmark, forming a conception gradually. Both the constant theme pattern and the simple linear pattern comply with this basic cognitive process. A constant theme pattern is used to profile one conception and the simple linear pattern is used to profile various conceptions. Although they are connected to different trajectors/conceptions, they comply with the cognitive process from figure to ground, or from trajector to landmark.