It should be noted that the concept of the customer is not applicable to all enterprises. One-to-one marketing need to factory customized, operating computer, communication network into a premise condition, therefore, implement the concept of customer requirements enterprise in the information collection, database construction, computer software and hardware to purchase a large amount of investment, and it is not every enterprise can do. Some companies, even if they are willing to spend their money, will inevitably invest more than the returns will bring. Customer ideas are best suited for those who is good at collect information on a single client enterprises, these enterprises marketing products can through the use of customer databases to realize cross-selling, or product need to purchase or upgrade periodically, or product value is very high. Customer perceptions tend to bring extraordinary benefits to such companies.
Cities, also known as urban settlements, are large settlements consisting of non-agricultural and non-agricultural populations. The densely populated areas are called cities, and generally include residential, industrial and commercial areas, with administrative functions. The cities involved in administrative functions may themselves involve a wide range of areas including residential areas, streets, hospitals, schools, public green spaces, office buildings, shopping malls, squares, parks and other public facilities.
Include neutral fat and lipid. The former is mainly for the supply of energy, the latter has important physiological functions. The basic components of lipids are fatty acids, which are essential fatty acids and non-essential fatty acids. There are three essential fatty acids: linoleic acid, linolenic acid and arachidonic acid. These three biological activities of essential fatty acids are not identical, with arachidonic acid to the maximum, linoleic acid is the second, linolenic acid for a minimum of long carbon chain fatty acids, in the brain and has a special role in the development and function of the retina. Animals lack essential fatty acids, growth retardation, appearance of skin symptoms (depilation, eczema dermatitis, scale skin and so on). It is reported that children who lack essential fatty acids have the same symptoms. But adult animals and people have difficulty producing symptoms, because there is a large amount of linoleic acid stored in the body. The deficiency of essential fatty acid can cause the change of fatty acid composition of phospholipid in cell membrane, thus affecting the function of membrane. It can also reduce the synthesis of prostaglandins. Prostaglandin precursor is 18 carbon and 20 carbon polyunsaturated fatty acids. It is suggested to measure the ratio of trienoic acid and tetraenoic acid in the blood as an indicator of the lack of essential fatty acids. This is due to the role of enzyme system in the metabolic process of fatty acids. When lack linoleic acid, linoleic acid by extending chain and the desaturation function and the amount of generated arachidonic acid is reduced, the other group of fatty acid, oleic acid metabolism strengthen, a large number of generated 20 carbon triene acid, therefore triene acid in the blood and the four acid ratio is increased. A person's essential fatty acid requirement is approximately 1 ~ 2% of the daily heat energy requirement.