Abstract: An amphoteric dissociation ion exchange separation medium, the surface of which is an amphoteric dissociation covalently-modified layer. When an environmental pH value is lower than the isoelectric point, pIm, of the covalently-modified layer, the type of net charges on the surface of the covalently-modified layer is positive and the separation medium has the properties of an anion exchanger; when the environmental pH value is higher than the pIm, the type of net charges on the covalently-modified layer surface is negative and the separation medium has the properties of a cation exchanger. The separation medium has the properties of an anion exchanger and a cation exchanger at both sides of the pIm, respectively. The pH of an eluent can be adjusted to allow the separation medium surface and the target substance to have the same type of net charges, so that the target substance can be released by electrostatic repulsion.

Abstract: An amphoteric dissociation ion exchange separation medium, the surface of which is an amphoteric dissociationcovalently-modified layer. When an environmental pH value is lower than the isoelectric point, pIm, of the covalently-modified layer, the type of net charges on the surface of the covalently-modified layer is positive and the separation medium has the properties of an anion exchanger; when the environmental pH value is higher than the pIm, the type of net charges on the covalently-modified layer surface is negative and the separation medium has the properties of acation exchanger. The separation medium has the properties of an anion exchanger and a cation exchanger at both sides of the pIm, respectively. The pH of an eluent can be adjusted to allow the separation medium surface and the target substance to have the same type of net charges, so that the target substance can be released by electrostatic repulsion.

Abstract: An amphoteric dissociation ion exchange separation medium, the surface of which is an amphoteric dissociation covalently-modified layer. When an environmental pH value is lower than the isoelectric point, pIm, of the covalently-modified layer, the type of net charges on the surface of the covalently-modified layer is positive and the separation medium has the properties of an anion exchanger; when the environmental pH value is higher than the pIm, the type of net charges on the covalently-modified layer surface is negative and the separation medium has the properties of a cation exchanger. The separation medium has the properties of an anion exchanger and a cation exchanger at both sides of the pIm, respectively. The pH of an eluent can be adjusted to allow the separation medium surface and the target substance to have the same type of net charges, so that the target substance can be released by electrostatic repulsion.

Abstract: A system and method for contests, advertising and reward by internet and mobiles APP. Some knowledge and contents will be written to the contest questions, which fit the contests by internet and mobile APP, to hold the single contests or the mixed contests by internet and mobiles APP. Any entities and any individuals can use these contests knowledge, the contest platform, the contests and the contest questions to make their advertisements and promotions. The contest platform will set up the studying scores, the contest scores and the reward scores. The platform will operate and manage the contests by the contest scores. The company which own the platform will sign some investing agreements with some companies. According the agreements, these companies will pay a specific ratio amount of their quarter realized net profit to support the operations of the contest platform.