< p > first, feathers can be classified into "feather" and "velvet". < /p >
< p > "feathers" have a central axis in their feathers called "feather axis", while the "feather axis" has two rows of hard "feather branches" called feathers. The main function of "feather" is to stir up air in bird flight, help to fly and support the bird body in high altitude. < /p >
< p > "velvet" is a feather with no feather shaft. It is composed of many slender and soft fibers gathered in a central point and connected to the body of birds. When the filament of every center is dispersed in the air, it looks like a flower, so it is called "velvet flower". The main function of < a href= "http://www.pmae.cn/" > velvet > /a "is to keep the body temperature of birds. < /p >
< p > birds or poultry have plumes, but only waterfowls and birds that live in water for some time in life have "velvet", such as ducks and geese. "Velvet" mostly grows in the chest, abdomen, neck and armpit of waterfowl. The main thing is keeping the temperature of waterfowl swimming. < /p >
< p > "velvet" is the only natural best and light insulation material. "Velvet" itself can not produce heat energy, its main insulation function is because each velvet flower has many soft velvet silk. When the fleece is spread, a three-dimensional POM ball is formed, and the best temperature insulator air is wrapped in the pouch. Thus, it becomes a top warmer bag. Besides preventing the body temperature from escaping, it can also resist the invasion of the cold air outside. < /p >
< p > birds already know how to build nests with "feather" and "velvet". When human cheeks steal birds' eggs, it is incidentally discovered that the mixture of "feather" and "velvet" is very soft, comfortable and warm. They begin to collect "velvet" to apply to clothes and clothes of < a href= "http:// www.pmae.cn/" > warmth < /a >. < /p >
< p > at present, most of the "velvet" used by humans are collected from water fowls, such as ducks and geese. In terms of volume, goose down is larger and the price is higher. The main reason is that the cost of raising goose is more expensive. < /p >
< p > secondly, there is basically no difference between the eiderdown and the goose down from the warmth level. Because "velvet" itself can not produce heat. The degree of warmth retention depends mainly on the following factors: < /p >
< p > 1, the fluffiness of "velvet" itself, which directly affects the number of air that can be wrapped up with the best thermal insulation object. < /p >
< p > 2, the number of "velvet" contained in the finished product. < /p >
< p > 3, clothing design, which includes the fabric, style and clothing structure used. < /p >
< p > generally speaking, the commercial 80/20 specifications should be 500 cubic inches of space under the fluffy condition. The higher the < a href= "http://www.pmae.cn/" > the bullness < /a > the better the degree of warmth, the embroidery of these high quality products is 600 or 700 words < /p >