Study Of Method For UV-shielding Capacity Evaluation Of Nano-oxides

As the thickness of the ozone layer has been destroyed during recent decades by the destruction of woods,the pollution of environment and the increasing quantity of carbon dioxide, people are likely to be exposed to an increasing dose of ultraviolet radiation. This has been correlated with a higher risk of damage to the human body such as premature aging of skin, skin cancer and cataract. however, the UVB radiation has always been thought to have the greatest effect on people,which can cause all kinds of dematosis, ageing and damage, the UVA radiation has been relatively weak. The latest study has revealed that producing skin cancer is the result of exposure to all waves of ultraviolet.It is the best way for humen to protect ourselves by choosing sunscreens protecting from UVA and UVB.Nano-oxides, such as titanium dioxide and zinc oxide, have characteristics making them ideal for use as broad-spectrum physical sunscreens in personal-care products. They are relatively transparent to visible light, but almost opaque to ultraviolet radiation. Compared to chemical sunscreens, nano-oxides have many advantages, such as none-toxcity, insipidity, chemical and thermally stability. As a good alternative to chemical sunscreens, nano-oxides have been widely used in many fields. SPF is used to evaluate the function of traditional organic sunscreens. It's impossible to set up a method to assess the UVA-shielding capabilities of nano-oxides just like UVB.However, there is no uniform detection method and standard to assess UV-shielding capabilities of nano-oxides now.This dissertation starts with the mechanism of nano-oxide UV-shielding and by the way of biological establishes two methods for evaluation the capacities of UV-shielding in broad-spectrum. At the aim of evaluating the capacity of UV-shielding efficiently and accurately ,electroanalysis is adapted with the TiO₂...