Abstract: Provided is a globally optimal robot visual positioning method and device based on point-line features. The method comprises the following steps: acquiring a priori three-dimensional map of a current scene constructed in advance; acquiring a current image of the robot and the inertial measurement data; calculating a pitch angle and a roll angle of the current robot pose according to the current inertial sensor data and the inertial sensor data in the priori map; matching the two-dimensional point-line features detected in the current image with three-dimensional point-line features in a priori map; separating the rotation and translation of the pose to be solved according to the matched feature pairs, solving the rotation and then solving the translation so as to complete the dimensionality reduction of the search space.

Abstract: The invention proposed a space vector pulse width modulation (SVPWM) method for any level cascaded H-bridge inverter. The multilevel space vector diagram is re-divided, and the coordinates of the nearest three vectors (NTVs) are directly obtained by judging the position of the reference vector. The duty cycles of the NTVs is calculated through additional vector which is equivalent to the reference vector. Then, the switching states are obtained by zero-sequence component and coordinate transformation, and the desired reference vector is synthesized for the SVPWM modulation. The invention realizes multilevel modulation in Cartesian coordinates without any iterative calculation, and the calculation is independent of the level number. Furthermore, the locating of the reference vector and the calculation of the duty cycles are simplified, and the calculation complexity is reduced.

Abstract: The present disclosure provides a circuit and method for expanding the lock range of injection-locked oscillators. The circuit includes N injection-locked oscillators and a lock detector, where the lock detector includes an alignment monitor, a clock selector, and N self-samplers. A pulse reference signal is inputted into the N injection-locked oscillators, and the output of each injection-locked oscillator is connected to the clock selector and the corresponding self-sampler. The self-samplers sample the outputs of the N injection-locked oscillators and output the sampling results to the alignment monitor. The alignment monitor monitors the sampling results, determines the locking conditions of the injection-locked oscillators, and turns off the unlocked oscillators. The clock selector selects a locked oscillator and transmits the output of the locked oscillator as a system lock.

Abstract: A sample to be measured is placed in a medium solution between two circular magnets to ensure that the sample to be measured is levitated in a set circular area between the two circular magnets, and a levitation position of the sample to be measured in the magnetic field is measured. The density of the sample is calculated according to formula (I): ? s = ? m + ? m - ? s g ? ? 0 ? ( B r ? ? B z ? r + B z ? ? B z ? z ) . Compared to the prior art, the method of the present disclosure provides a novel method for measuring a density of a substance, in which the involved device is easy to operate and has low cost, and the measurement results are easy to observe and have high accuracy.

Abstract: A phase frequency detector-based high-precision feedback frequency measurement apparatus and method: a Field Programmable Gate Array (FGPA) roughly measures a frequency fx of a measured time-frequency pulse by an equal-precision frequency measurement method; a Direct Digital Synthesizer (DDS) automatically synthesizes a frequency fx? according to the fx roughly measured by the FPGA; the fx and the fx? are sent to a phase frequency detector for performing phase frequency detection and then sent to the FPGA after passing through a charge pump, a low-pass filter circuit, and an (Analogue-to-Digital) A/D converter; the FPGA processes a frequency difference obtained by the phase frequency detector and then transmits the processed frequency difference to the DDS to form a negative feedback frequency measurement system so that the DDS continuously adjusts the fx? according to a frequency difference measurement result until the output of the DDS is stable.

Abstract: A patrol helmet and method for livestock and poultry farms is described herein. The patrol helmet is wirelessly connected to an online farm management system on a cloud platform. The patrol helmet includes a helmet body, a controller, an augmented reality (AR) display component, an infrared (IR) camera, and a visible light camera. The AR display component is secured at the bottom edge of the helmet body. Both the IR camera and the visible light camera are disposed on the helmet body. The IR camera, the visible light camera, and the AR display component each is electrically connected to the controller. The IR camera and the visible light camera are configured to photograph livestock or poultry in an area in front of a wearer to obtain a temperature and an image of the livestock or the poultry.

Abstract: An optimization method for capturing proteins by multi-column continuous chromatography (MCC), including the following steps: step 1, under the conditions of a set loading protein concentration and an arbitrary load residence time, performing a single time of protein breakthrough experiment to obtain a protein breakthrough curve; step 2, under a set breakthrough percentage for a target protein, integrating the breakthrough curve to obtain a single-column loading capacity and establishing a linear relationship between the interconnected load time and the load residence time; step 3, solving for the optimal number of operating columns for capturing proteins by MCC based on step 2; step 4, solving for the optimal load residence time for capturing proteins by MCC based on step 2, step 3; and step 5, solving for the maximum productivity of capturing proteins by MCC based on step 4.

Abstract: Provided is a supergravity directional solidification melting furnace equipment, including a supergravity test chamber and, mounted in the supergravity test chamber, a high-temperature heating subsystem, a crucible, and an air-cooling system. The supergravity test chamber is mounted with a wiring electrode and a cooling air valve device. The high-temperature heating subsystem is fixed in the supergravity test chamber. The crucible and the air cooling system are provided in the high-temperature heating subsystem. The high-temperature heating subsystem includes upper, middle, and lower furnaces, a mullite insulating layer, upper and lower heating cavity outer bodies, upper and lower heating furnace pipes, and a crucible support base. A high-temperature heating cavity is divided into upper and lower parts, is provided therein with a spiral groove, and is fitted with a heating element. The crucible support base is provided therein with a vent pipe channel into which a cooling air is introduced.

Abstract: The present disclosure discloses a method for extracting pectin rich in RG-I, in particular to an ultrasound and pressure assisted method for extracting pectin rich in RG-I. The main process includes: dispersing sieved citrus peel powers in alkaline solution containing sodium borohydride (20 to 50 mM); performing an ultrasound and pressure combined treatment on the above solution at 25 to 40° C., the treatment conditions include: static pressure of 0.2 to 0.4 MPa, ultrasonic intensity of 0.5 to 3.5 W/mL, and treatment time of 20 to 40 min; centrifuging the ultrasonically processed solution to remove residues, and sequentially carrying out precipitation with ethanol (50% to 80% v/v), precipitant dialysis (3000 to 3500 Da), and vacuum freeze drying on the extracted solution to obtain pectic polysaccharide.

Abstract: A tracer particle spreading device for a boundary layer flow visualization experiment based on a flat plate includes a tracer particle generator, a smoke storage box, and a wall-surface particle distribution box. Fume and oil are pressurized by a micro pump and flows into a heating pipe to be heated and vaporized, and then is ejected from a nozzle to form tracer particles. The tracer particles enter the smoke storage box via a smoke guiding tube. An axial flow fan is mounted on a wall surface of the smoke storage box. The tracer particles enter a cavity of the wall-surface particle distribution box via the smoke guiding tube, and the tracer particles are rectified by a rectifying plate and ejected from a spreading slit. An outlet of the spreading slit is at an angle of 15° with respect to an experiment flat plate.

Abstract: The present disclosure relates to the field of biotechnology, and particularly to use of a tomato gene mSlBZR1L in changing the morphology of tomato fruits. The present disclosure discloses a tomato gene mSlBZR1L comprising a nucleotide sequence as set forth in SEQ ID No: 3, and the gene can extend the length of the tomato fruits.

Abstract: A blackboard eraser cleaning device is provided and includes an outer shell (1). A cover (2) is arranged at the upper part of the outer shell (1), an inner shell (3) is arranged inside the outer shell (1). A clamping mechanism (19) is arranged at the upper end of the inner shell (3). A leaning station (8) is defined inside the clamping mechanism (19). A cylinder (9) is arranged around the clamping mechanism (19). A height adjustment mechanism (10) is arranged inside the outer shell (1). The height adjustment mechanism (10) includes a servo (101) arranged inside the outer shell (1) and located on a side of the inner shell (3). According to the present application, a variety of cleaning modes may be achieved to meet the actual usage of the blackboard eraser.

Abstract: Provided is a hemostatic composition comprising trypsin and zeolite, wherein pore channels of the zeolite are micropores, the zeolite contains divalent metal cations, and the mass ratio of the trypsin to the zeolite is 1:200-4:10. In the present invention, the trypsin specifically binds to the zeolite, allowing the trypsin to maintain a certain conformation on the surface of the zeolite and to obtain a higher procoagulant activity, thereby obtaining a hemostatic composition with an excellent blood coagulation effect. The hemostatic composition of the present invention has the advantages of a simple preparation method, low cost and convenient use, and can be widely used in hemostasis during trauma and operations, especially in emergent hemostasis in hemophilia patients.

Abstract: A low-computation underwater acoustic wake-up method based on a multi-carrier signal is provided. A multi-carrier signal corresponding to communication nodes is constructed, absolute values of the multi-carrier signal in a window at a receiver are summed for signal arrival detection, and then frequency points of the multi-carrier signal are detected many times by using the real fast Fourier transform to realize wake-up detection. The method is suitable for accurate wake-up at any distance within a maximum communication distance of two underwater acoustic nodes, has a small amount of calculation, and is suitable for low-power single-chip microcomputers. The modem can be in a low-power sleep state for a long time.

Abstract: The present invention discloses a brain machine interface decoding method based on spiking neural network, comprising: (1) constructing a liquid state machine model based on a spiking neural network, the liquid state machine model consists of an input layer, an middle layer and an output layer, wherein, a connection weight from the input layer to the middle layer is Whh, a loop connection weight inside the middle layer is Whh, a readout weight from the middle layer to the output layer is Wyh; (2) Inputting a neuron spike train signal, and training each weight with the following strategy: (2-1) Using STDP without supervision to train the connection weight Whh from the input layer to the middle layer; (2-2) Setting the loop connection weight Whh inside the middle layer by means of distance model and random connection, and obtaining a middle layer liquid information R(t); (2-3) Using ridge regression with supervision to train the readout weight Wyh from the middle layer to the output layer, and establishing a ma

Abstract: A method and a device for remote acquisition of correlated pseudo-random numbers based on semi-trusted hardware. When applied to semi-trusted hardware, the method comprises: acquiring a random seed of a sender and a selected number of a receiver; generating a plurality of first correlated pseudo-random numbers and first commitment seeds according to the random seed and a predetermined category of the correlated pseudo-random number; generating a first commitment value and a first open value by a commitment mechanism according to the first correlated pseudo-random numbers and the first commitment seeds; generating a Merkle proof according to the first commitment value and the selected number; sending the first correlated pseudo-random numbers, the first commitment value, the first open value and the Merkle proof corresponding to the selected number to the receiver.

Abstract: A device and a method for reducing wind resistance power of a large geotechnical centrifuge are provided. A semicircular tube cylindrical cooling device is provided between an internal side of a high-speed rotor system and a cylindrical shell. A serpentine top semicircular tube cooling plate is provided right above a hanging basket, and return helium gas inlet holes are provided at a center of the top semicircular tube cooling plate. A helium gas in a helium gas storage tank passes through helium gas outlets on the helium gas inlet pipes, and enters a centrifuge chamber from a bottom sealing plate. The helium gas is used to replace air in the centrifuge chamber to reduce the wind resistance power and corresponding energy consumption. No vacuuming is required, so sealing requirements are lower. Heat dissipation equipment is placed inside the centrifuge chamber, and a helium gas circulation wind duct is added.

Abstract: A method for recognizing an identity and a gesture based on radar signals includes: reading a radar echo signal reflected by various gestures of a tester and received by a radar sensor; frequency-mixing the radar echo signal with a radar transmission signal; after filtering and centralizing a frequency-mixed signal, training and obtaining a neural network capable of identity verification and a neural network capable of gesture recognition; in a real-time detection process, verifying an identity of a user; and if the identity is verified, determining that a gesture of the user is valid; verifying the gesture of the user and executing a corresponding operation according to correspondence between the gesture of the user and an operation. It can be determined by the method whether the gesture belongs to the corresponding user and whether the operation corresponding to the gesture is performed according to the determined result.

Abstract: A continuous quantitative spraying structure for sterilization of harvested fruits is provided. The continuous quantitative spraying structure includes a track provided thereon with equally spaced trays for conveying fruits, where the trays each include a circular tray body; a central part of the tray body is provided with a central hole allowing the fruit to fall off; a bottom part of the central hole is provided with two parallel rollers; an inner bottom surface of the tray body is provided with a flap; an inner end of a central shaft of the roller passes through the flap, and is fixed to a rolling wheel; a bearing is provided between the roller and the flap; the track is provided with a spraying sterilization section; the spraying sterilization section is sequentially provided with 3 to 4 sets of sterilization nozzles above a tray conveying route.

Abstract: A three-dimensional detection method for red tide algae based on holographic imaging is provided, including: constructing a coaxial optical path based on a structure of a Mach-Zehnder interferometer; determining reconstruction distances of the system under different object distances; constructing an original hologram database of the algae; selecting an original hologram, and two reconstructed holograms with different reconstruction distances as a three-dimensional spatial sample of the original hologram; labeling algae in sample, and recording species and bounding boxes of the algae; training a target detection network with the sample of the holograms and a label file; detecting, with the trained target detection neural network, the sample of the algae to obtain species and a quantity of plankton in imaged water. The disclosure further provides a three-dimensional detection device for red tide algae. The method can improve a detection speed and detection accuracy of the red tide algae.