For meeting the requirements of high-precision and high-speed in on-line detection for strip and plate’s internal defects, in the paper, based on elaborating methods and principle of conventional ultrasonic testing, the research status of traditional ultrasonic testing technology and non-contact ultrasonic testing techniques, there analysis and discuss the problems and causes in the process of detection. In the end, the trend of development is given.
Recent laboratory experiments demonstrate that electrical conductivity of upper mantle (UM) minerals is greatly increased by small amounts of water or by partial melt. Determination of deep conductivity using electromagnetic (EM) methods can thus provide constraints on the presence of volatiles and melting processes in UM. Probing conductivity at UM depths requires EM data with periods of a few to one cycle per day. This is a challenging period range for EM studies due to the spatially complex ionospheric source that dominates at these periods. The idea of exploiting tidal signals for EM studies of the Earth is not new, but so far it was used only for interpretation of inland and transoceanic electric field data due to M2. Emphasis in this work is made on a discussion of sea bottom magnetic field of the same origin.
A flow and sediment mathematical model was built under three-dimensional hybrid coordinate to simulate Wenzhou Oufei tidal flat and its neighboring sea area, and the verification was down. The calculation results and the observed data are identical well. In estuary area, the sediment concentration is the highest, then outside the estuary. In Oufei tidal flat area, the sediment concentration is relatively high, and it decreases gradually towards the open sea. Through the simulation, the characteristics and the basic law of sediment concentration distribution was reproduced.
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