Abstract: A three-dimensional ultrasonic imaging method includes transmitting an ultrasonic wave to a fetal head; receiving an ultrasonic echo, obtaining an ultrasonic echo signal, and obtaining the three-dimensional volume data of the fetal head according to the ultrasonic echo signal; according to the characteristics of a median sagittal section of the fetal head, detecting the median sagittal section in the three-dimensional volume data; and displaying the median sagittal section.

Abstract: A positive active material, a secondary battery, a battery module, a battery pack, and an electrical device are disclosed. The positive active material includes a spinel-type lithium-manganese-containing composite oxide with a molecular formula of Li1+xAaMbXcMn2?a?b?c?xO4?t. In the molecular formula: A is a doping element for a manganese site of the spinel-type lithium-manganese-containing composite oxide; M is used for combining with O to form a second phase containing a polyoxyanion, and M includes one or more of B, C, N, Si, P, S, or Cl; X includes one or more of Mg, Al, Si, Ca, Sc, Ti, Cr, Fe, Co, Ni, Cu, Zn, or Zr; and the molecular formula satisfies: ?0.1?x?0.3, 0<a?0.2, 0<b?0.2, 0<c?0.7, and 0?t?0.2.

Abstract: A secondary battery includes a positive electrode sheet having a positive electrode active material and a non-aqueous electrolyte. The positive electrode active material includes a central core material and a modification layer disposed on a surface of the central core material. The modification layer including an orthophosphate with a molecular formula Aa+x[PO4]3?y, where A denotes one or more of Li, Na, K, Rb, Cs, Mg, Ca, Ba, Ni, Fe, Co, Ti, Al, Cr, V, Nb, and W, 1?a?6, and ax=3y. The non-aqueous electrolyte includes a fluorinated phosphate with a molecular formula Bb+m[PO1+cF3-c]c?n, where B denotes one or more of Li, Na, K, Rb, Cs, Mg, Ca, and Ba, 1?b?2, c denotes 1 or 2, and bm=cn.

Abstract: The present invention relates to an intelligent test device for a substrate, comprising a main case, a detection turntable, a feeding mechanism, a contact detection mechanism for testing the OFF-pressure of contacts from spring pieces, a discharging mechanism and an electric control box, the detection turntable, the feeding mechanism, the contact detection mechanism and the discharging mechanism being all ON-connected to the electric control box. The test device of the present invention can complete the OFF-pressure detection of the longitudinal and transverse contacts of the substrate automatically without requiring any manual operation, thus the test device of the present invention is easy to use, and the detection accuracy and the detection efficiency are high. Furthermore, the ex-factory pass rate of products is guaranteed, the cost is reduced and defective substrates can be classified and sorted automatically.

Abstract: The present invention relates to an intelligent test device for a substrate, comprising a main case, a detection turntable, a feeding mechanism, a contact detection mechanism for testing the OFF-pressure of contacts from spring pieces, a discharging mechanism and an electric control box, the detection turntable, the feeding mechanism, the contact detection mechanism and the discharging mechanism being all ON-connected to the electric control box. The test device of the present invention can complete the OFF-pressure detection of the longitudinal and transverse contacts of the substrate automatically without requiring any manual operation, thus the test device of the present invention is easy to use, and the detection accuracy and the detection efficiency are high. Furthermore, the ex-factory pass rate of products is guaranteed, the cost is reduced and defective substrates can be classified and sorted automatically.