Abstract: A first-order differential microphone array (FODMA) system with a steerable beamformer. The system includes a plurality (M) of microphones located on a substantially planar platform, the plurality of microphones comprising a first subset (M_1) of microphones and a second subset (M_2) of microphones, and a processing device, communicatively coupled to the plurality of microphones, configured to construct a first sub-beamformer based on the first sub-set (M_1) of microphones and a target beampattern at a steering angle ?, wherein the first sub-beamformer is characterized according to a first-order cosine (cardioid) first sub-beampattern, construct a second sub-beamformer based on the second sub-set (M_2) of the microphones and the target beampattern at the steering angle ?, wherein the second sub-beamformer is characterized according to a first-order sinusoidal (dipole) second sub-beampattern, and generate the steerable beamformer based on the first sub-beamformer and the second sub-beamformer.

Abstract: Disclosed is a method and a device for online measurement of a binocular laser system. The method may include: mounting a workpiece and a measuring block, such that lasers emitted from a first and a second laser instrument are projected onto two measuring surfaces of the measuring block, and projection positions of the lasers emitted from the first and second laser instruments are maintained unchanged; and performing at least one round of cyclic operations until a forming process of the workpiece ends. The cyclic operations may include: acquiring a plurality of pieces of point cloud data, and separating point cloud data to obtain a first, a second, a third, and a fourth point cloud data set; generating a rigid matching relationship; generating a coordinate system relationship; converting the fourth point cloud data set into a fifth point cloud data set; and generating an intermediate shape and size of the workpiece.

Abstract: Surface pressure measurements on rotating models are important for flow phenomenon identification, understanding flow mechanisms and model aerodynamic design. The disclosure discloses a periodic pressure field measurement system based on the superposed lifetime of pressure sensitive paint, including pressure sensitive paint, a pulse light source, a camera, a synchronizer and a computer. A lifetime superposition method is disclosed in the disclosure for measuring periodic pressure fields of pressure sensitive paint.

Abstract: The present disclosure discloses a MEMS grating and a fabrication method. The MEMS grating includes a substrate layer, an insulation layer and a deformable layer. The deformable layer is made of a continuous conductive material, the insulation layer is distributed along transverse intervals on the substrate layer, and a cavity is formed between every two adjacent insulation layers. The deformable layer includes movable grating bars and fixed grating bars. The fixed grating bars are fixedly connected with the insulation layer, and the movable grating bars correspond to the cavities. A plurality of through holes are formed in the movable grating bars. During wet etching, the movable grating bars generate upwards buckling deformation, which increase an initial gap between the movable grating bars and a substrate. An adhesion effect caused by the wet etching is eliminated, which reduces permanent failures caused by the adhesion effect.

Abstract: A multi-posture bedside writing pen includes a pen shell, a pen tip holder, a fiber rod and a fiber ink storage tube. The fiber ink storage tube is connected with the pen shell and located in the pen shell. The pen tip holder is connected with one end of the pen shell. The pen tip holder is axially provided with a through hole. The fiber rod is inserted into the through hole, one end of the fiber rod is exposed outside the pen tip holder, and an other end of the fiber rod is inserted into the fiber ink storage tube. A first gap is provided between the pen tip holder and the fiber ink storage tube.

Abstract: Disclosed are a nickel-based superalloy formed by selective laser melting and a preparation method thereof. In the method, CrFeNb alloy powder is used as a grain refiner, and its element composition is within the composition range of a nickel-based superalloy powder to ensure that the prepared nickel-based superalloy has the same element composition with the original alloy; the grain size in the nickel-based superalloy could be refined by the addition of CrFeNb alloy powder, such that the anisotropic columnar grain structure in the alloy is transformed to equiaxed grain structure, thereby improving mechanical properties of the alloy.

Abstract: A preparation method of a flame-retardant ultrathin PEO-based solid electrolyte is disclosed. The method includes the following steps: preparing a CN support layer; synthesizing a flame retardant-loaded multifunctional filler: HNT@TMP; mixing and stirring PEO, LiTFSI, and HNT@TMP in a certain ratio in acetonitrile to obtain PEO-based solid electrolyte slurry; coating both sides of the CN support layer obtained in step S1 with the PEO-based solid electrolyte slurry obtained in step S3, and performing drying; and performing hot pressing to obtain a PEO-based solid electrolyte.

Abstract: Disclosed is a chip-level disc-type acousto-optic standing wave gyroscope including a substrate and a gyroscope structure placed on an upper surface of the substrate; the substrate is in a shape of a circular disc; the gyroscope structure includes an acoustic wave drive module and an optical detection module, the acoustic wave drive module is arranged in a circular shape taking the center of the circular disc as an origin and extending outward radially, and the optical detection module is arranged in the middle of the acoustic wave drive module and is annular; the acoustic wave drive module includes an annular interdigitated transducer, a metal electrode layer group uniformly sputtered on the annular interdigitated transducer, annularly arranged metallic pillars and an annular reflection grating, respectively placed in sequence from center of the disk radially to periphery of the disk; the optical detection module includes a first grating coupler, an optical waveguide at a light source input end, a first coup

Abstract: The present disclosure provides a staged shearing and forming method for a T-bar cylindrical member, comprising: controlling a shear working surface of a shear spinning wheel in contact with a surface of a cylindrical member blank; controlling a circumferential rotation of the cylindrical member blank; controlling a working surface of a flow spinning wheel to be in perpendicular contact with a surface of the unsaturated I-bar cylindrical member and controlling the cylindrical member blank to be maintained in a circumferential rotational state; controlling the flow spinning wheel to thin one side of the unsaturated I-bar cylindrical member; controlling a fractal working surface of a fractal spinning wheel in contact with a top of the saturated I-bar structure; controlling a working surface of a flat spinning wheel to be in perpendicular contact with a surface of the Y-bar cylindrical member.

Abstract: Disclosed is a nighttime cooperative positioning method based on an unmanned aerial vehicle (UAV) group, falling within the technical field of aircraft navigation and positioning. According to the present disclosure, the cooperative visual positioning and the collision warning for UAVs are realized by means of light colors of the UAVs, respective two-dimensional turntable cameras and a communication topology network, without adding additional equipment and without relying on an external signal source, avoiding external interference. Compared with the positioning method in a conventional manner, in the present disclosure, the system is effectively simplified, and the cooperative positioning among the interiors of a UAV cluster can be realized relatively simply and at a low cost to maintain the formation of the UAV group.

Abstract: A space pen refill for an extravehicular activity, including a ball, a refill body, a fiber rod and a fiber ink-storage tube; the ball is rotatably connected in one end of the refill body, a segment of the ball is exposed outside the refill body, the fiber ink-storage tube is connected to an inside of the refill body, one end of the fiber rod is inserted into the fiber ink-storage tube, an other end of the fiber rod close to the ball is used to supply ink for the ball, an end face of an other end of the refill body is connected with first and second one-way valves, the first and second one-way valves are unidirectionally communicated with the inside and the outside of the refill body, and gas flow directions in the first and second one-way valves are opposite.

Abstract: The present disclosure relates to a method and system for determining transportation safety of pulverized coal. The method includes: acquiring coal particle data during transportation of pulverized coal, where the coal particle data is size data of a coal particle accumulation; determining a particle model of the coal particle accumulation during the transportation of the pulverized coal according to the size data; establishing a constitutive theoretical model to describe all flow regimes of a coal granular medium; numerically discretizing the constitutive theoretical model by using a numerical method to obtain discrete equations; calculating a movement process of the coal granular medium according to the discrete equations and the particle model of the coal granular medium to obtain a calculation result; plotting the calculation result by using post-processing software Tecplot to obtain relevant information of a coal particle flow; and determining whether the pulverized coal transportation process is safe.

Abstract: Process for the preparation of a ceramic nanowire preform, in particular, a process for the preparation of a ceramic nanowire preform by combining a template technique and a preceramic polymer conversion technique. The process uses carbonaceous material as a template, and prepares an isotropic ceramic nanowire preform by controlling the ratio of a precursor to a solvent, the amount of a catalyst and the ratio of a prepared precursor solution to the carbonaceous template, wherein the preform is isotropic and has lower bulk density and higher volume fraction.

Abstract: A system and method of generating binaural signals includes receiving, by a processing device, a sound signal including speech and noise components, and transforming, by the processing device using a deep neural network (DNN), the sound signal into a first signal and a second signal. The transforming further includes encoding, by an encoding layer of the DNN, the sound signal into a sound signal representation in a latent space, rendering, by a rendering layer of the DNN, the sound signal representation into a first signal representation and a second signal representation in the latent space, and decoding, by a decoding layer of the DNN, the first signal representation into the first signal and the second signal representation into the second signal.

Abstract: The disclosure relates to a video anomaly detection method based on human-machine cooperation, in which video frames and traditional descriptors of optical stream of an image are utilized as an input for auto-encoder neural network coding, and converted into a representation content of a hidden layer, and then the representation content of the hidden layer is decoded, reconstructed and output. The auto-encoder network is trained with normal samples. In a test stage, if an input is a normal sample, a final reconstructed error keeps high similarity with an input sample; on the contrary, if the input is an abnormal sample, the final reconstructed error deviates greatly from the input sample.

Abstract: A method for preparing an asymmetric wettable polyimide fiber-based photothermal aerogel is provided. The method includes the steps: uniformly mixing polyimide powder and a solvent, then, performing electrostatic spinning, and cutting an obtained fiber felt into pieces for later use; mixing the broken fibers, polyamic acid and tert-butyl alcohol, then, performing shearing to form a stable dispersion liquid for low-temperature directional freezing, and performing freeze-drying and high-temperature thermal imidization to obtain a polyimide fiber-based aerogel material; and soaking the above aerogel material in a hydrophilic monomer solution for a polymerization reaction, and then performing low-temperature directional freezing and freeze-drying to obtain a hydrophilic polyimide fiber-based aerogel.

Abstract: The disclosure discloses a global pressure acquisition system for a rotating model, including a CCD camera, a signal generator, a stroboscopic pulse LED light source, a photoelectric sensor, a preset counter, and a controller. The disclosure further discloses a global pressure acquisition method for a rotating model. The disclosure has the beneficial effects that, by using the non-contact measuring method disclosed by the present disclosure, a measured model and a flow field are not damaged, a submillimeter-level spatial resolution is achieved, it is ensured that the acquired PSP image of the rotating model is clear, and the signal to noise ratio of the image is increased.

Abstract: The disclosure discloses a measuring device for dynamic characteristics of pressure sensitive paint, including a PSP sample wafer, a dynamic pressure sensor, an oscilloscope, a light source, a photomultiplier tube, a bandpass filter, a loudspeaker, a power amplifier, and a signal generator. The disclosure further discloses a measuring method for dynamic characteristics of pressure sensitive paint. The disclosure has the following beneficial effects: by using the measuring device disclosed by the present disclosure, the continuous sinusoidal pressure wave with any frequency can be generated, and has the frequency precision that does not exceed 0.01 Hz, an optical path is not shielded, high stability is achieved, and the amplitude and phase characteristics of the pressure frequency of the PSP can be precisely captured.

Abstract: Surface pressure measurements on rotating models are important for flow phenomenon identification, understanding flow mechanisms and model aerodynamic design. The disclosure discloses a periodic pressure field measurement system based on the superposed lifetime of pressure sensitive paint, including pressure sensitive paint, a pulse light source, a camera, a synchronizer and a computer. A lifetime superposition method is disclosed in the disclosure for measuring periodic pressure fields of pressure sensitive paint.

Abstract: Disclosed is a chip-level resonant acousto-optic coupling solid-state wave gyroscope based on MEMS technology. A surface acoustic progressive wave mode sensitive structure and a micro-ring resonant cavity optical detection structure are combined in the gyroscope. Through acousto-optic effect, mechanical strain of the device crystal caused by wave vibration of a primary surface acoustic wave and a secondary surface acoustic wave caused by Coriolis force is converted into a variation in the refractive index of an optical waveguide etched on the device, so that the optical signal transmitted in the waveguide diffracts, thereby generating frequency modulation. Meanwhile, a micro-ring resonant cavity using the resonance principle peels off the frequency change introduced by the primary surface acoustic wave, and obtains an output signal containing external angular velocity information.