【正文】 ction 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 the different regions, followed by the use of principal ponent analysis, to further reduce the number of dimensions. Development RBF neural networkbased classification model for feature extraction. electronic nose to detect the Pink Lady brand apple shelf life, results with routine quality testing (hardness, starch index, acidity, etc.) related contrast, showed a good correlation Supriyadi electronic nose of different maturity snakeskin fruit detection, results showed that the electronic nose can be a good distinction。Amico pointed out that the electronic nose can distinguish between benign skin lesions and birthmarks tumor or melanoma。s latest two technologies solid phase micro extraction and Electronic Nose monitor phenanthrene degradation in contaminated soil. The Philippines is a hydrophobic organic contaminants, contains three fused benzene rings belonging to polycyclic aromatic hydrocarbons. The detection and analysis of the electronic nose results show that, by PCA treatment, contaminated and uncontaminated soil samples can be significant distinction.Public SafetyIn order to ensure the security of public places, check explosives in airports, railway stations, docks and other places is an important and difficult task. These places usually have more staff, speed of flow of people, plex background, more belongings. Therefore, the accuracy of these places explosives, quick detection has bee the focus of the work and difficult. Compared to traditional detection methods, the electronic nose has small size, low cost, and high reliability. . Yinun and other electronic nose for explosives and chemical weapons detection of volatile gases. With polymer coating Iran and other electronic nose sensor array for the war moving analog classification, warning of an impending threat of chemical weapons, people to safely leave the contaminated area. In summary, the electronic nose has a short response time, speed detection, sample preparation is simple determination of the wide scope of the assessment, objective assessment of odor pensate for the description of human sensory ambiguity, subjectivity and imprecision, and gas chromatography plicated shortings. Painstaking research, researchers in various fields from a single sensing element to the sensor array to the image sensor, the electronic nose technology fruitful research results. Many foreign advent of electronic nose products, such as France, Alpha MOS system is mainly used for quality identification products such as meat, coffee, cereals, UK Aroma SCAN system is mainly used for cheese, meat quality testing, there39。 application of a precise verification techniques and the detection output of the steps on the selected model. The electronic nose applied to the assessment o