The purpose is different: abstraction is to save time and money. People who read academic journals usually do a lot of professional reading, so they want to make full use of their time. The abstract can tell them whether it is worth reading the rest of the 60-page paper. The introduction is to stimulate readers' interest in reading. They may be anecdotes or facts, but they should be presented in a way that makes readers wonder what will happen next.

The content is different: the introduction does not include methods, results or conclusions, but it still needs some more in-depth information, such as the explanation of assumptions and problems, the novelty and importance of the research, etc. The introduction should include references, and it is best to write it after all the papers are completed. Abstract and introduction can be found at the beginning of written works, hoping to prepare readers for further reading. It is a minimalist version including methods, results and conclusions, and should be written from the background or purpose, so as to be concise but informative. There is no need for references, and the length is generally not more than 200-250 words. Short and pithy is the main feature of academic journal abstracts. Just briefly summarize the research objectives, methods, results and conclusions in 1 ~ 2 sentences respectively. The main task of introduction is to outline the basic content and outline of the full text to readers.