4 results about "Field strength" patented technology

The invention discloses a rectangular waveguide covered with a dielectric layer in the technical field of communication cables. A waveguide structurally comprises the rectangular waveguide and the dielectric layer, wherein the dielectric layer is arranged on the rectangular waveguide; the wall of the rectangular waveguide is provided with a slot array formed by a plurality of slots at uniform intervals along the axis direction. The dielectric layer is added on the rectangular slot waveguide, and the electric field intensity of a working area on the surface of the rectangular slot waveguide is obviously improved; the divergence degree of an electromagnetic field is reduced; meanwhile, proper thickness and dielectric constant of the dielectric layer are selected, and the radiation intensity of a working area of a rectangular slot waveguide cable can be controlled. The rectangular waveguide can be applied to a communications based train control (CBTC) railway mobile communication system, the near field intensity on the upper side of the rectangular slot waveguide is improved, the space convergence of an electric field is improved, and the system has the best working condition.

The invention provides a high voltage direct current cable insulating material and a preparation method thereof, wherein the high voltage direct current cable insulating material comprises a main material and an auxiliary material, the main material is a low density polyethylene resin, and the auxiliary material comprises a polystyrene resin, a cross-linking agent and an antioxidant. Compared withthe common cross-linked polyethylene, the high voltage direct current cable insulating material of the invention has the following characteristics that the direct current breakdown field strength isincreased within the temperature range of 30-90 DEG C, the direct current breakdown field strength is improved by 72.9% at the temperature of 70 DEG C, and the direct current breakdown field strengthis improved by 43.7% at the temperature of 90 DEG C.

The invention provides a control method and a control device of a magnetic resonance system. The control method comprises the following steps: measuring and recording radio frequency field data; obtaining an amplitude estimation value of the radio frequency field based on the radio frequency field data and a particle swarm algorithm; setting an amplitude control parameter of the radio frequency pulse based on the amplitude estimation value; acquiring a setting instruction of the sequence mode of the radio frequency pulse; and outputting a control signal based on the amplitude control parameter and the setting instruction. According to the configuration, on one hand, actual data of the radio frequency field can be found through measurement, on the other hand, the amplitude estimation value of the radio frequency field can be obtained based on the particle swarm optimization, the influence of noise errors is reduced, and the radio frequency amplitude calibration precision and speed are improved. Therefore, the problem that in the prior art, due to the fact that the field intensity of the radio frequency field is affected by various factors, the expected field intensity is changed, and the imaging effect is affected is solved.