Abstract: An ultra-wideband electromagnetic band gap (EBG) structure includes multiple EBG units in an array. Each EBG unit includes a power plane, a dielectric substrate and a ground plane from top to bottom. The power plane includes a patch, a coupled complementary split ring resonator (C-CSRR) and a plurality of semi-improved Z-bridge structures. Each edge of the patch is provided with a semi-improved Z-bridge structure. The C-CSRR is provided within a ring formed by the semi-improved Z-bridge structures. The Z-bridge structure includes a first horizontal branch, a first vertical branch, a second horizontal branch and a second vertical branch connected in sequence. The second vertical branch is connected to the patch. First horizontal branches of adjacent EBG units are connected to each other. A circuit board including the aforementioned EBG structure is also provided.

Abstract: The technology provides a computing device having a human presence sensor module. An image sensor of the human presence sensor module captures imagery, and the imagery is not disseminated outside of the human presence sensor module to another part of the computing device. One or more machine learning models, each trained to identify whether one or more persons are present in the imagery, are retrieved from memory within the human presence sensor module. The imagery received from the image sensor is processed using the one or more machine learning models to determine whether one or more persons are present in the imagery. Upon detection that one or more persons are present in the imagery, the human presence sensor module issues a signal to an operating system of the computing device so that the computing device can respond to that presence by performing one or more actions.

Abstract: The present disclosure relates to the technical field of polymer material, and discloses a device and method for online preparation of a modified polylactic acid material with a polylactic acid melt. The device comprises a twin-screw extruder, a first solid modifier hopper, a polylactic acid melt pipeline and a polylactic acid melt feedstock metering pump, wherein the first solid modifier hopper is connected with Zone I of the twin-screw extruder, the polylactic acid melt pipeline is connected with Zone IV of the twin-screw extruder. The method for online preparation of modified polylactic acid material with the device can avoid degradation of the polylactic acid caused by the secondary processing, improve mechanical property of the prepared polylactic acid and reduce production cost.

Abstract: The present invention relates to the technical field of polylactic acid preparation, and discloses polylactic acid polymerization reaction apparatus and system. The polylactic acid polymerization reaction apparatus comprises a polymerization reactor and an agitating assembly arranged in a flow channel of the polymerization reactor, wherein the agitating assembly comprises an electromagnetic winding mechanism and a magnetic induction element, the electromagnetic winding mechanism is arranged along the inner wall of the polymerization reactor around the magnetic induction element, with clearance formed between the electromagnetic winding mechanism and the magnetic induction element, so that the magnetic induction element and the electromagnetic winding mechanism can induce electromagnetic induction, and thereby the magnetic induction element can rotate around its own axis; a threaded groove is formed on the magnetic induction element.