Abstract: A method for preventing cracking of nickel-based superalloy fabricated by selective laser melting (SLM) belongs to the field of additive manufacturing (AM). The method of preparing an as-built part with a high density, no crack defects, and good mechanical properties includes: reducing the content of elements Zr and B forming low melting point phase in a nickel-based superalloy, adjusting the total content of Al and Ti in the alloy to 4.5 wt % or below, and combining with the control of special SLM process parameters. The new method has the advantages of a reasonable component design, a simple preparation process, and good performance of the as-built part, and therefore is suitable for large-scale application.

Abstract: The present invention provides a printed circuit board (PCB) board, a core for manufacturing the PCB board and a method for manufacturing the PCB board. The PCB board is in a shape of a rectangle and comprises a fiber layer formed of interlacedly weaved fiberglasses, a metal layer affixed onto a surface of the fiber layer, and a pair of differential signal traces formed on the metal layer, wherein extending directions of the fiberglasses lie at acute angles with respect to a length direction of the rectangle, and the pair of differential signal traces extends along a width direction or the length direction of the rectangle. The PCB board can effectively reduce the possibility of the skew distortion during the transmitting process of the differential signal through adjusting the angle between the fiberglasses and the edge of the core without adjusting or redesigning the original circuit layout.

Abstract: A printed circuit board, an in-circuit test structure and a method for producing the in-circuit test structure thereof are disclosed. The in-circuit test structure comprises a via and a test pad. The via passes through the printed circuit board for communicating with an electrical device to be tested on the printed circuit board. The test pad is formed on an upper surface of the printed circuit board and covering the via, wherein a center of the via deviates from a center of the test pad. In the in-circuit test, the accuracy of the test data can be improved by means of the in-circuit test structure provided by the present invention, and thus the reliability of the test result is ensured. Also, the test efficiency of the in-circuit test is improved.

Abstract: The present invention provides a printed circuit board (PCB) board, a core for manufacturing the PCB board and a method for manufacturing the PCB board. The PCB board is in a shape of a rectangle and comprises a fiber layer formed of interlacedly weaved fiberglasses, a metal layer affixed onto a surface of the fiber layer, and a pair of differential signal traces formed on the metal layer, wherein extending directions of the fiberglasses lie at acute angles with respect to a length direction of the rectangle, and the pair of differential signal traces extends along a width direction or the length direction of the rectangle. The PCB board can effectively reduce the possibility of the skew distortion during the transmitting process of the differential signal through adjusting the angle between the fiberglasses and the edge of the core without adjusting or redesigning the original circuit layout.

Abstract: An exemplary backlight module (20) includes a light guide plate (21), a plurality of point light sources (22), and a transparent light diffusing element (23). The light guide plate includes a light incident surface (211). The point light sources are positioned adjacent to the light incident surface. The light diffusing element is positioned between the point light sources and has a light incident surface. The light diffusing element includes a plurality of recesses (231) which face the light incident surface and correspond to the point light sources. The light diffusing element can diffuse light from the point light sources, therefore increasing emitting angles of the point light sources. The recesses of the light diffusing element can make light from the point light sources more uniform.