Abstract: The present disclosure provides a connection structure between an aluminum alloy drill pipe body and a steel joint of an aluminum alloy drill pipe, including a first joint at an end of the aluminum alloy pipe body and a steel second joint; wherein the first joint includes a first external threaded section and a second external threaded section provided from outside to inside thereof, and a major diameter of the first external threaded section is smaller than that of the second external threaded section; and wherein the second joint includes a first internal threaded section which is able to be fitted with the first external threaded section and a second internal threaded section which is able to be fitted with the second external threaded section, and a pitch diameter of the second external threaded section is larger than that of the second internal threaded section.

Abstract: A rotor assembly including a rotating shaft, a rotor core, a permanent magnet, a magnetic ring support, and a magnetic ring. The permanent magnet is mounted on the outer side surface of the rotor core. The magnetic ring is nested on the magnetic ring support, and the magnetic ring support and the rotor core are made as a whole by injection molding. The rotor assembly is relatively simple to produce, low in cost, and features improved efficiency.

Abstract: A brushless DC motor structure including a motor body, a controller, and a fan radiator. The fan radiator is mounted between the motor body and the controller to disperse heat from the motor body and the controller. The brushless DC motor structure increases air flow on the surface of the motor body and the controller by the fan radiator and speeds up heat dispersion, and meanwhile effectively controls the operating temperature of the motor body and the controller. Thus, the brushless DC motor structure has an excellent heat dispersion capability, and the failure rate thereof has been largely reduced.

Abstract: A rotor assembly including a rotating shaft, a rotor core, a permanent magnet, a magnetic ring support, and a magnetic ring. The permanent magnet is mounted on the outer side surface of the rotor core. The magnetic ring is nested on the magnetic ring support, and the magnetic ring support and the rotor core are made as a whole by injection molding. The rotor assembly is relatively simple to produce, low in cost, and features improved efficiency.

Abstract: A brushless DC motor structure including a motor body, a controller, and a fan radiator. The fan radiator is mounted between the motor body and the controller to disperse heat from the motor body and the controller. The brushless DC motor structure increases air flow on the surface of the motor body and the controller by the fan radiator and speeds up heat dispersion, and meanwhile effectively controls the operating temperature of the motor body and the controller. Thus, the brushless DC motor structure has an excellent heat dispersion capability, and the failure rate thereof has been largely reduced.

Abstract: The present invention is directed towards the use of the masked palm civet Paguma larvata (“civet”) as an animal model system for SARS, and is based on the novel demonstration of the present invention that civets may be infected with exogenous coronavirus, and that such infection produces SARS-like symptoms in these infected animals. The present invention is directed to a civet model system for the study of the infection, replication, and clinical effects of exogenously introduced human SARS-CoV coronavirus strains, civet SARS-CoV-like coronavirus strains, or variants or derivatives thereof, and to the development of vaccines (or other methods of prevention) or treatment of infection or transmission to other civets or humans of these human SARS-CoV coronavirus strains, civet SARS-CoV-like coronavirus strains, or variants or derivatives thereof.