Abstract: The present invention relates to a preparation and purification method for cationic quaternary ammonium salt of sodium hyaluronate in homogeneous medium. By adding a homogeneous solvent and a sodium hyaluronate solid to a vessel, heating the vessel until the contents are dissolved to form a homogeneous system, adding an aqueous solution of 2,3-epoxypropyltrimethylammonium chloride (GTA) to the homogeneous system, then adding a base catalyst, and stirring at a preset temperature to carry out a graft reaction, a graft product is obtained wherein 2,3-epoxypropyltrimethylammonium chloride is grafted to the oxygen atom of the hydroxymethyl group of sodium hyaluronate. By using the method, a graft product wherein 2,3-epoxypropyltrimethylammonium chloride is grafted to the oxygen atom of the hydroxymethyl group of sodium hyaluronate is obtained. Addition of salts is avoided during the reaction, a grafting yield up to 0.69 is obtained, and coagulation occurred to the product is effectively solved.

Abstract: A three-way catalyst having low NH3 formation is disclosed. The catalyst includes a carrier and a coating material. The coating material includes a precious metal active component and a catalytic material. The precious metal active component includes a first precious metal active component and a second precious metal active component. The first precious metal active component is a composition containing Ru. The second precious metal active component is a composition containing Pt, Pd and Rh. Alternatively, the second precious metal active component is a composition containing Pd and Rh.

Abstract: The present invention discloses a ringtone uploading service method and system used in color ring back tone (CRBT) service. The present invention is that when a ringtone system successfully uploads a ringtone to at least one but not all ringtone servers, it records ringtone uploading information, sends a message about the successful uploading of the ringtone to an uploading terminal, and re-uploads the ringtone to the ringtone servers to which the ringtone has not been successfully uploaded. The ringtone uploading solution proposed in the present invention will greatly improve the success rate of ringtone uploading.

Abstract: The present invention discloses a ringtone uploading service method and system used in color ring back tone (CRBT) service. The present invention is that when a ringtone system successfully uploads a ringtone to at least one but not all ringtone servers, it records ringtone uploading information, sends a message about the successful uploading of the ringtone to an uploading terminal, and re-uploads the ringtone to the ringtone servers to which the ringtone has not been successfully uploaded. The ringtone uploading solution proposed in the present invention will greatly improve the success rate of ringtone uploading.