【正文】 K 8th Annual Meeting of the European chemical sensing research organization is the turning point of the study of the electronic nose. At this meeting, Gardner led by the University of Warwick in gas sensing sensing research team published a paper sensor in gas measurement parties and applications, focusing on the concept of pattern recognition, caused academia extensive interest. In 1989, the North Atlantic Treaty Organization held a special chemical sensor information processing symposium, dedicated to artificial olfactory system design of these two topics. In August 1991, the North Atlantic Treaty Organization was held in Iceland thematic sessions of the first electronic nose. The electronic nose Since then rapid development. 1994, Gardne: a review article on the electronic nose, formally proposed the concept of electronic nose, marking the electronic nose technology into the mature stage of development. Since 1994, after more than ten years of development, the electronic nose research has made rapid progress. For the study of the electronic nose mainly in the side of the sensor and electronic nose hardware design, pattern recognition theory, the electronic nose in food, agriculture, pharmaceutical, biofield applications, electronic nose, and biological systems while. The hardware design of the sensor and the electronic nose and electronic nose applications in the field of food and agriculture is a hot spot in the study of the electronic nose. Crewe town in Cheshire, England pany successfully developed an electronic nose, the tests showed that the patient skin wound bacteria can sniff out the erosion remind doctors to take appropriate measures in a timely manner. His study of the electronic nose is a matrix posed of 32 different organic polymer sensor, very sensitive to the smell of various volatile pound, the pound is different, the reaction is different. Typically, bacterial growth will be issued chemical odor the electronic nose contact with the odor, each sensor resistance will change. Format Since each sensor corresponding to a different kind of chemical substances, posed of 32 kinds of the same change in resistance would respectively represent the fingerprint of the different odors. The tests showed that the electronic nose can be found if there is the presence of bacteria only need a few hours. In the past, using the methods of the laboratory tests, usually 13 days to get the results. The gas sensors in the system of electronic nose, the gas sensor is the perceived odor of the basic unit, are also key factors. However, due to the strong specificity of the gas sensor, which makes the detection of the gas mixture or the presence of interfering gases, the single sensor is difficult to obtain a higher accuracy of detection and identification of. Therefore, the portion of the odor perception of the electronic nose often use a plurality of a gas sensor having a different selectivity, according to a certain array bination, the use of the crosssensitivity of a variety of gases, the different odor molecules in its role of the surface is converted to a convenient calculate the timerelated physical signal group, can be measured to achieve the analysis of the mixed gas. At present, the main types of electronic nose sensors conductive sensors, piezo sensors, fieldeffect sensors, fiber optic sensors, various sensors have their own advantages and disadvantages, the electronic nose can adapt to a variety of uses.圖3Application and prospects:FoodElectronic nose wide range of applications in the field of food, including grains, fruits, dairy products, meat, alcohol and tobacco with a distinct odor characteristics of the food. With the growing depth of the electronic nose research, has been involved in many aspects of food science. According to different application purpose and function of the electronic nose, electronic nose in food research can be divided into: the monitoring of the production process, the freshness of the assessment, the shelf life of the survey, true and false verification, and other aspects. The most important thing is that the quality control of dairy products in the production process in its monitoring of the quality. Analysis of volatile ponents of milk has bee one of the most potential means to obtain milk information and to distinguish the different kinds of milk, is mainly used for monitoring of different heat treatment process. The electronic nose in the dairy processing has been widely used, for example, the the Danish green cheese maturity process monitoring, quality control of Swiss cheese flavor mixture pattern recognition and cheese taste detection, and detection of the shelf life of cheese, cheese, another include the detection of microorganisms in milk distinguish different kind of ice cream, online monitoring of yoghurt fermentation. 2001, Italy and other electronic nose to identify two different heat treatment of milk: one is pasteurized, another treated after ultrahigh temperature sterilization. The five different SnO2 sensor array, in response to the data obtained by the sol gel technology to identify the two kinds of milk processing and tracking the dynamic process of milk corruption reactor by principal ponent analysis, be able to tell its good quality The bad and the whole corrupt process, and in the dairy production industry has begun to apply this instrument to go for quality control analysis. The experiment, the sensor has a good repeatability, and the response time is very short, about 2 ~~ 3min. The electronic nose applications in dairy biggest advantage is that you can line control, which can not be pared to any other method. American using a mercial electronic nose system, based on the conductive polymer used for the analysis of beef freshness. Raw data obtained by the electronic nose systems using different signal processing techniques pretreatment, pretreatment data reprocessing to extract the characteristics of