Abstract: A security inspection device, a security inspection system and a security inspection method are provided, the device includes: a support frame defining an inspection channel; a first X-ray accelerator provided at a position of a top portion of the support frame and the position is offset from a centerline of the inspection channel, where the first X-ray accelerator is configured to radiate a first X-ray towards the inspection channel to inspect an object; a second X-ray accelerator configured to radiate a second X-ray to the inspection channel to inspect the object; and a detector apparatus, including: detector modules provided on the support frame and facing the first X-ray accelerator and the second X-ray accelerator, the detector modules receive the first X-ray and/or the second X-ray to form a transmission image of the object; the first X-ray, the second X-ray, and the detector modules are located in the same plane.

Abstract: The present application discloses a preparation method of SM non-woven fabrics for roof anti-slip, which belongs to the technical field of roofing materials, comprising preparing spunbond non-woven fabric raw materials, preparing spunbond non-woven fabrics, preparing meltblown non-woven fabric raw materials, preparing primary SM non-woven fabrics, and post-processing; the spunbond non-woven fabric raw materials are prepared by uniformly mixing polypropylene with a low melt flow index, polypropylene with a high melt flow index, sodium alginate, antioxidant 1010, zinc stearate, ultraviolet absorber UV-531, polyvinyl alcohol, reinforcing agent, adhesive agent, and nano titanium dioxide. The present application can avoid the problem that the SM non-woven fabrics cannot be fully bonded together and are easy to delaminate when being combined, can also solve the problem of fabric breakage during high-speed production, and can also improve the wear resistance, strength, and stiffness of SM non-woven fabrics.

Abstract: A power semiconductor device includes: a substrate; drain metal; a drift region; a base region; a gate structure; a first conductive type doped region contacting the base region on the side of the base region distant from the gate structure; a source region provided in the base region and between the first conductive type doped region and the gate structure; contact metal that is provided on the first conductive type doped region and forms a contact barrier having rectifying characteristics together with the first conductive type doped region below; and source metal wrapping the contact metal and contacting the source region.

Abstract: An adaptive load optimization method for a resonant gate drive circuit is provided to optimize the switching loss, turn-on loss and gate drive loss under different MOSFET loads. A data table is pre-stored in a digital signal processor chip (DSP), and voltages and pre-charge times, corresponding to a low total loss, of the resonant gate driver obtained by actual tests in case of different load currents are recorded in the data table; and in actual application, after an analog-to-digital converter terminal (ADC) samples a load current, a load current, closest to the sampled load current, is read from the data table, and the digital signal processor chip (DSP) is enabled to perform table look-up to obtain an optimized voltage and pre-charge time of a gate drive circuit.

Abstract: An in-situ shear test device for holes in rock-soil mass include an axial loading system, a cutting power system, a rotation system, an upper cutterhead control system, a shear test system, and a lower cutterhead control system, which belongs to the field of geotechnical engineering and geological engineering technology. The device can accurately obtain the in-situ shear strength parameters in the hole of rock and soil, improve the engineering design level, and ensure the safety and stability of the project. The device adopts an in-situ shear test device in the hole of rock and soil mass with the above structure, which can solve the problems of difficulty in in-situ shear test for the holes in deep rock-soil mass, lack of test device, difficulty in radial test, difficulty in loading while shearing, and difficulty in multi-point in-situ test.

Abstract: An in-situ testing instrument for soil moisture in a hole includes a test bracket extended into a hole, a retracting and releasing mechanism used to drive the test bracket to rise and fall in the hole, a moisture test mechanism arranged on the test bracket, a plug-and-pull drive mechanism used to drive the moisture test mechanism to insert into soil on a side of the hole or to be pulled out by the soil on a side of the hole, and a signal receiving mechanism arranged on a ground, the signal receiving mechanism is electrically connected with the moisture test mechanism. The above-mentioned in-situ testing instrument and method for soil moisture in a hole can eliminate the steps of taking soil, packaging, weighing, and drying, and improve the test efficiency and the test accuracy.

Abstract: An insulated gate bipolar transistor, comprising an anode second conductivity-type region and an anode first conductivity-type region provided on a drift region; the anode first conductivity-type region comprises a first region and a second region, and the anode second conductivity-type region comprises a third region and a fourth region, the dopant concentration of the first region being less than that of the second region, the dopant concentration of the third region being less than that of the fourth region, the third region being provided between the fourth region and a body region, the first region being provided below the fourth region, and the second region being provided below the third region and located between the first region and the body region.

Abstract: The present invention discloses a high-threshold power semiconductor device and a manufacturing method thereof. The high-threshold power semiconductor device includes, in sequence from bottom to top: a metal drain electrode, a substrate, a buffer layer, and a drift region; further including: a composite column body which is jointly formed by a drift region protrusion, a columnar p-region and a columnar n-region on the drift region, a channel layer, a passivation layer, a dielectric layer, a heavily doped semiconductor layer, a metal gate electrode and a source metal electrode. The composite column body is formed by sequentially depositing a p-type semiconductor layer and an n-type semiconductor layer on the drift region and then etching same. The channel layer and the passivation layer are formed in sequence by deposition. Thus, the above devices are divided into a cell region and a terminal region.

Abstract: An in-situ detection robot and method for geological information without disturbance of in-situ stress, including a sleeve, a drilling unit set at the top of the sleeve, a dumping unit set inside the sleeve, and a support propulsion unit is set outside the sleeve, the top of the dumping unit extends into the drilling unit, a detection unit is set between the drilling unit and the support propulsion unit, and the robot tail is connected to a control unit; the dumping unit is used to discharge soil drilled from a hole of the drilling unit to the ground, the support propulsion unit is used to realize support, the detection unit is used to detect geological information of surrounding environment of the robot, the control unit is used to control the drilling unit, the support propulsion unit and the detection unit, and the control unit collects and processes the geological information.

Abstract: A high-speed remote landslide simulation test device with a variable angle includes a support adjustment component, slide plates, and loose leaves. The device first transmits the operation paths of adjusting the slide plate at different angles to the controller, and the personnel operates the control panel to control the support jack, the motor, and the electromagnet to start and stop through the controller, the output shaft of the motor drives the stainless steel threaded rod to rotate, the controller first energizes one electromagnet and disconnects the other three electromagnets, which can only make the stainless steel threaded rod rotate in a fixed position inside the inner threaded pipe, and the three inner threaded pipes follow the rotation direction of the stainless steel threaded rod, thus, the position of the support jack can be moved separately.

Abstract: An inductor current estimation method for a DC-DC switching power supply using a voltage sampling module, a data conversion module, a switching signal counting module, an inductor voltage calculation module and a digital filter module, comprising: processing an input voltage and an output voltage by the voltage sampling module and the data conversion module to obtain a converted input voltage and a converted output voltage which have a same number of bits; comparing a node voltage with a reference voltage, and then obtaining a duty cycle by the switching signal counting module; and then, outputting an average voltage of two terminals of an inductor and a parasitic resistor by the inductor voltage calculation module, and finally, obtaining an estimated inductor current by the digital filter module.

Abstract: A control method for a four-switch buck-boost converter is provided. The control method adopts four-stage control, and divides the load range into two sections and adopts different control strategies according to a critical load value corresponding to optimal control. In Boost mode, before the critical load, T1 and T2 are kept constant, T3 is a minimum value for realizing soft-switching, and T4 decreases with the increase of the load; when the critical load is reached, T4 drops to 0; and after the critical load, T1, T2, T3 and T increase with the load. In Buck mode, before the critical load, T2 and T3 are kept constant, T1 is a minimum value for realizing soft-switching, and T4 decreases with the increase of the load; when the critical load is reached, T4 drops to 0; and after the critical load, T1, T2, T3 and T increase with the load.

Abstract: An enhancement-mode N-channel and P-channel GaN device integration structure comprises a substrate, wherein an Al—N nucleating layer, an AlGaN buffer layer, a GaN channel layer and an AlGaN barrier layer are sequentially arranged on the substrate, and the AlGaN barrier layer and the GaN channel layer are divided by an isolation layer; a P-channel device is arranged on one side of the isolation layer and comprises a first P-GaN layer, a first GaN isolation layer and a first P+-GaN layer are sequentially arranged on the first P-GaN layer, a first source, a first gate and a first drain are arranged on the first P+-GaN layer, the first gate is inlaid in the first P+-GaN layer, and a gate dielectric layer is arranged between the first gate and the first P+-GaN layer; and an N-channel device is arranged on the other side of the isolation layer.

Abstract: A multi-phase high-precision current sharing control method applied to constant on-time control is provided, wherein a current difference between continuously sampled current of each line and mean current is processed by a PI compensation module and a low-pass filter module to obtain on-time regulation data. A high bit of the regulation data controls the value of counter reference Vref in an on-time control module, and a low bit controls the length of an enabled delay line in a delay line module. The counter timing control of the on-time control module is combined with the delay line timing control of the delay line module to improve the control precision of a DPWM. The method takes COT control of a Buck converter as a typical application. Compared with a multi-phase COT controller without a current-sharing mechanism, the method can improve the stability and reliability of the system.

Abstract: The present application discloses a preparation method of SM non-woven fabrics for roof anti-slip, which belongs to the technical field of roofing materials, comprising preparing spunbond non-woven fabric raw materials, preparing spunbond non-woven fabrics, preparing meltblown non-woven fabric raw materials, preparing primary SM non-woven fabrics, and post-processing; the spunbond non-woven fabric raw materials are prepared by uniformly mixing polypropylene with a low melt flow index, polypropylene with a high melt flow index, sodium alginate, antioxidant 1010, zinc stearate, ultraviolet absorber UV-531, polyvinyl alcohol, reinforcing agent, adhesive agent, and nano titanium dioxide. The present application can avoid the problem that the SM non-woven fabrics cannot be fully bonded together and are easy to delaminate when being combined, can also solve the problem of fabric breakage during high-speed production, and can also improve the wear resistance, strength, and stiffness of SM non-woven fabrics.

Abstract: A control method for a four-switch buck-boost converter is provided. The control method adopts four-stage control, and divides the load range into two sections and adopts different control strategies according to a critical load value corresponding to optimal control. In Boost mode, before the critical load, T1 and T2 are kept constant, T3 is a minimum value for realizing soft-switching, and T4 decreases with the increase of the load; when the critical load is reached, T4 drops to 0; and after the critical load, T1, T2, T3 and T increase with the load. In Buck mode, before the critical load, T2 and T3 are kept constant, T1 is a minimum value for realizing soft-switching, and T4 decreases with the increase of the load; when the critical load is reached, T4 drops to 0; and after the critical load, T1, T2, T3 and T increase with the load.

Abstract: An in-situ shear test device for holes in rock-soil mass include an axial loading system, a cutting power system, a rotation system, an upper cutterhead control system, a shear test system, and a lower cutterhead control system, which belongs to the field of geotechnical engineering and geological engineering technology. The device can accurately obtain the in-situ shear strength parameters in the hole of rock and soil, improve the engineering design level, and ensure the safety and stability of the project. The device adopts an in-situ shear test device in the hole of rock and soil mass with the above structure, which can solve the problems of difficulty in in-situ shear test for the holes in deep rock-soil mass, lack of test device, difficulty in radial test, difficulty in loading while shearing, and difficulty in multi-point in-situ test.

Abstract: An enhancement-mode N-channel and P-channel GaN device integration structure comprises a substrate, wherein an Al—N nucleating layer, an AlGaN buffer layer, a GaN channel layer and an AlGaN barrier layer are sequentially arranged on the substrate, and the AlGaN barrier layer and the GaN channel layer are divided by an isolation layer; a P-channel device is arranged on one side of the isolation layer and comprises a first P-GaN layer, a first GaN isolation layer and a first P+-GaN layer are sequentially arranged on the first P-GaN layer, a first source, a first gate and a first drain are arranged on the first P+-GaN layer, the first gate is inlaid in the first P+-GaN layer, and a gate dielectric layer is arranged between the first gate and the first P+-GaN layer; and an N-channel device is arranged on the other side of the isolation layer.

Abstract: In the monolithically integrated GaN-based half-bridge circuit, a nucleation layer, a buffer layer, a channel layer and a barrier layer are sequentially provided on a conductive substrate, the barrier layer and the channel layer are separated by isolation layers, and a diode, an integrated capacitor, a low-side transistor, a high-side transistor, a first integrated resistor and a second integrated resistor are provided. The half-bridge circuit includes: a low-side transistor and a high-side transistor, wherein a drain of the low-side transistor is connected to a source of the high-side transistor and also connected to an output terminal Vout, and a substrate of the low-side transistor is connected to a substrate of the high-side transistor, wherein a series resistor is connected in parallel to a drain of the high-side transistor and a source of the low-side transistor.

Abstract: A multi-phase high-precision current sharing control method applied to constant on-time control is provided, wherein a current difference between continuously sampled current of each line and mean current is processed by a PI compensation module and a low-pass filter module to obtain on-time regulation data. A high bit of the regulation data controls the value of counter reference Vref in an on-time control module, and a low bit controls the length of an enabled delay line in a delay line module. The counter timing control of the on-time control module is combined with the delay line timing control of the delay line module to improve the control precision of a DPWM. The method takes COT control of a Buck converter as a typical application. Compared with a multi-phase COT controller without a current-sharing mechanism, the method can improve the stability and reliability of the system.