Plastic products have brought great convenience to our lives by way of its scalable manufacturing process, light weight, robust mechanical properties, versatility, low cost and resistance to corrosion. These products have been widely used in various fields such as packaging, food industry, electronics, construction and many other industries; among which about 16 billion disposable coffee cups are consumed every year and half billion plastic straws are discarded every day worldwide. However, it takes as long as 450 years or even longer for some plastics to degrade especially single-use plastics bags, lunchboxes and disposable cups, accounting for 40% of the total plastic production and rendering severe “white pollution”. Meanwhile, every year about 8 million tons of plastic waste is dumped into oceans, which has caused significant harm to marine life. Current treatment to plastic includes land filling, incineration and recycling among which landfill treatment is the prim...
It is difficult to give an exact definition for the life, as the nature of life is not clear. According to Encarta@ Wodd English Dictionary, definition of living is: "Spiritual existence transcending physical death; the period from birth to death; the quality that makes living animals and plants different from dead organisms and inorganic matter. Its functions include the ability to take in food, adapt to the environment, grow, and reproduce". The biological world is viewed as a hierarchy of levels. These levels include chemicals, organelles, cells, organs, organisms, and ecologies. There are three conceptions for life: as a loose cluster of properties, a specific set of properties, and metabolization. Several hundred years ago, people thought that there was a vitalism inside life bodies that keep the body to be a life. The scientific results absolutely denied the existence of vitalism. The demise of vitalism told us that no super physical substance or force or spirit...