Abstract: The present disclosure relates to a magnesium-based raw material with low thermal conductivity and low thermal expansion and a preparation method thereof. According to the technical solution, 40-60 wt % fused magnesia particles, 30-40 wt % fine monoclinic zirconia powder, 5-20 wt % fine zirconium oxychloride powder, 0.5-1.5 wt % calcium hydroxide nanopowder, 0.2-0.5 wt % calcium hydroxide nanopowder, and 0.1-0.3 wt % maleic acid are stirred for 15 min to mix well in a high-speed mixing mill at a constant temperature of 25° C. to obtain a mixed powder; and the mixed powder is mixed through a ball mill at a constant temperature of 25° C. for 3 min, roasted in a high temperature furnace at 250-400° C. for 0.5-3 h, and finally cooled to room temperature. The magnesium-based refractory material prepared has the advantages of relatively low thermal conductivity, low thermal expansion coefficient, excellent dispersibility, and strong resistance to slag penetration and erosion.

Abstract: A method, including: 1) inputting a multi-story point cloud, and segmenting a story and an inter-story connection region based on an elevation histogram of the point cloud in a vertical direction; 2) segmenting rooms for each story based on a grid map projected onto an XOY plane respectively, wherein the XOY plane is parallel to a flooring; 3) segmenting indoor space cells for each story based on a vector wall line respectively; constructing a vector indoor plan based on superimposition of the vector and the grid for each story respectively; and 5) establishing a three-dimensional model of a multi-story structure by deleting an overlapping surface between the story and the connection region according to the Boolean intersection.

Abstract: The disclosure discloses a multi-time-scale reliability evaluation method of a wind power IGBT considering fatigue damage and a system thereof. Lifetime information of a power device is comprehensively extracted by using multiple time scales. An electro-thermal coupling model of an IGBT module is established to obtain a junction temperature data. A steady-state junction temperature database of the IGBT in different aging states is established. Based on a SCADA monitoring data, the junction temperature data is outputted in real-time through the electro-thermal coupling model and a real-time thermal stress cycle number is calculated in a short-term time-scale profile, and a wind speed probability distribution curve is obtained in a long-term time-scale profile. A maximum thermal stress cycle number that the IGBT can withstand in different aging stages is obtained in advance and a cumulative damage degree and an estimated lifetime of the IGBT of the wind power converter are calculated.

Abstract: The invention discloses an artificial nacre material with layered structure and preparation method thereof. The preparation method includes the following steps: uniformly mixing a carbonated cementitious material and water at a water-solid ratio of 0.3 to 1.2 to obtain a carbonated cementitious material suspension; treating the carbonated cementitious material suspension by a freeze-casting process to obtain a carbonated cementitious material coagulation with layered structure; treating the carbonated cementitious material coagulation with the layered structure by a freeze-drying process to obtain a carbonated cementitious material with layered structure; treating the carbonated cementitious material with layered structure by a carbonization process to obtain an artificial nacre material with layered structure.

Abstract: A method of preparing a cement hydration product nano-thin film, the method including: (1) preparing a cement hydration product; (2) preparing a water sacrificial layer film; (3) depositing the cement hydration product obtained in (1) on the surface of the water sacrificial layer film obtained in (2) to obtain a cement hydration product film; and (4) immersing the cement hydration product film in a saturated aqueous solution of calcium hydroxide to dissolve the water sacrificial layer film to obtain a nano-thin film of the cement hydration product.

Abstract: A robot and a collecting method for collecting polymetallic nodules in deep-sea are provided. The robot includes an underwater moving carrier and a collecting module, and the collecting module is fixedly mounted on the underwater moving carrier. The collecting module includes a collecting frame, a collecting pump, a rack and a collecting tube, the collecting frame is installed at the bottom of the rack, and the collecting pump is a piston pump, which includes a piston and a cylinder with open lower-end. The upper part of the cylinder is a collecting area, the lower part is a piston stroke area, the collecting tube is connected to the cylinder of the collecting area, and a check valve is arranged in the middle of the piston.

Abstract: A method and a system of predicting an electric system load based on wavelet noise reduction and empirical mode decomposition-autoregressive integrated moving average (EMD-ARIMA) are provided. The method and the system belong to a field of electric system load prediction. The method includes the following steps. Raw load data of an electric system is obtained first. Next, noise reduction processing is performed on the load data through wavelet analysis. The noise-reduced load data is further processed through an EMD method to obtain different load components. Finally, ARIMA models corresponding to the different load components are built. Further, the ARIMA models are optimized through an Akaike information criterion (AIC) and a Bayesian information criterion (BIC). The load components obtained through predicting the different ARIMA models are reconstructed to obtain a final prediction result, and accuracy of load prediction is therefore effectively improved.

Abstract: A circuit health state prediction method and system based on an integrated deep neural network are provided and relates to a technique for predicting a power electronic circuit failure. The invention serves to identify and diagnose a health state of a simulation circuit based on historical data by using an integrated deep neural network, and the method includes: carrying out parameter aging simulation experiments for different devices; extracting a series of time domain features of output signals through a temporal transformation method, and establishing health indices of the devices based on an improved angular similarity; predicting a health state of the simulation circuit in degeneration by using CAE and LSTM-RNN; and predicting validity of the circuit health state prediction method by referring to relevant evaluation indices. The invention is capable of effectively predicting the health state of the simulation circuit and is highly accurate and easy to implement.

Abstract: An optical fiber grating sensing method applied to small-scale fire source monitoring are provided, distinguishing two concepts of a spatial resolution and a perception resolution, under the premise of ensuring the spatial resolution of a traditional fiber Bragg grating sensing system, only increase the number of fiber Bragg gratings covered by a single pulsed optical signal without changing a pulse width of a pulsed optical signal, so as to improve the perception resolution of the system without increasing the requirements for a hardware circuit, and truly shorten an interval between adjacent fiber Bragg gratings. Improving the perception resolution of the system, which not only ensures the spatial resolution of the system, but also realizes the monitoring of small-scale fire sources; by adopting a simple feature extraction algorithm to obtain fire temperature information in different areas, the temperature detection speed of the system is fast.

Abstract: A preparation method of an ant nest like porous silicon for a lithium-ion battery comprises: (1) enabling a magnesium silicide raw material to react for 2-24 h in an ammonia gas or an atmosphere containing an ammonia gas at 600-900° C. to obtain a crude product containing porous silicon; and (2) subjecting the crude product containing porous silicon to an acid pickling treatment to obtain the ant nest like porous silicon. The preparation method has the advantages of simplicity and easiness. A large amount of porous silicon can be obtained by directly heating the magnesium silicide raw material in the ammonia gas or a mixed gas of the ammonia gas and an inert gas with a high yield.

Abstract: An automatic classification method of whole slide images (WSIs) for cervical tissue pathology based on confidence coefficient selection. The automatic classification method includes steps: S1: dividing the WSIs for the cervical tissue pathology into small pieces having set size, gathering the small pieces of each WSI into a packet, and removing blank pieces in the packets; S2: building a deep CNN model; S3: training the deep CNN for designated rounds; S4: performing sequential arrangement and connection to obtain feature vectors of WSIs by using the trained deep CNN as the feature extractor; S5: training a support vector machine classifier; and S6: processing the WSIs for the cervical tissue pathology, to be classified, through step S1 and step S4 to obtain the feature vectors of the images, and inputting the feature vectors into the trained support vector machine classifier to realize classification.

Abstract: A method for correcting a phase jump caused by polarization-induced fading in optical fiber phase demodulation, including the steps of: 1, selecting a demodulated phase in the case of non-depolarization as historical sample data; 2, determining an autoregressive coefficient and a moving average coefficient of the autoregressive moving average model for the demodulated phase; 3, establishing a Kalman prediction model for the demodulated phase, and deriving recursive equations of the Kalman prediction model for the demodulated phase; and 4, judging whether a jump point exists in the actual demodulated phase, determining polarization states of lights if the jump point exists, and correcting the jump point when the polarization states of the lights are in polarization orthogonality by replacing the actual demodulated phase with a predicted phase value. The disclosure ensures the correctness of subsequent vibration-based signal processing.

Abstract: The invention discloses an unmanned surface vessel (USV) formation path-following method based on deep reinforcement learning, which includes USV navigation environment exploration, reward function design, formation pattern keeping, a random braking mechanism and path following, wherein the USV navigation environment exploration is realized adopting simultaneous exploration by multiple underactuated USVs to extract environmental information, the reward function design includes the design of a formation pattern composition and a path following error, the path following controls USVs to move along a preset path by a leader-follower formation control strategy, and path following of all USVs in a formation is realized by constantly updating positions of the USVs.

Abstract: The disclosure discloses an IGBT module reliability evaluation method and device based on bonding wire degradation, which belong to the field of IGBT reliability evaluation. The realization of the method includes: obtaining a relationship between a IGBT chip conduction voltage drop Uces and an operating current Ic along with a chip junction temperature Tc; for an IGBT module under test, obtaining the conduction voltage drop Uces-c of the IGBT chip through the operating current Ic and the chip junction temperature Tc; obtaining an external conduction voltage drop Uces-m of the IGBT module by using a voltmeter; performing subtraction to obtain a voltage drop at a junction of a IGBT chip and a bonding wire, and combining the operating current to obtain a resistance at the junction; determining that the IGBT module has failed when the resistance at the junction increases to 5% of an equivalent impedance of the IGBT module.

Abstract: The disclosure provides a silicon photovoltaic cell scanning eddy current thermography detection platform and a defect classification method. The technical solution adopted by the disclosure is: firstly, fixing the position of the electromagnetic inductive coil and the thermal imager, and using the main conveyor belt to carry the silicon photovoltaic cell to move forward on the production line to form a scanning eddy current heating of the silicon photovoltaic cell. Secondly, the defect temperature information is obtained through the thermal imager in terms of thermal image sequences. Thirdly, the feature extraction algorithms are used to extract the silicon photovoltaic cell defect features. Finally, the image classification algorithms are used to classify the silicon photovoltaic cell defects, and the sorting conveyor belts are used to realize the automatic sorting of silicon photovoltaic cells with different types of defects on the production line.

Abstract: A method of jitter detection and image restoration for high-resolution TDI CCD satellite images. The method includes: obtaining a parallax image after a sub-pixel matching method relying on a correlation coefficient and least squares algorithm; transferring a jitter offset from an image space to an object space by an integral transformation function (ITF); dealing with a continuous push-broom mode of cameras in a discrete way with a denser sampling strategy according to a continue dynamic shooting model (CDSM), obtaining a specialized CDSM and feeding it back to the ITF; applying the accurate ITF to the obtained parallax image and conducting the jitter curve fitting to achieve the jitter detection; estimating a correspondent partial PSF according to the CDSM and the obtained jitter curve; carrying out an adaptive restoration based on context through optimal window Wiener filtering, by means of multiple input and single output to completes the image restoration.

Abstract: Electromagnetically-induced cement concrete crack self-healing diisocyanate microcapsules include raw materials, in parts by weight, comprising 15-55 parts of petroleum resin, 5-10 parts of paraffin, 5-10 parts of polyethylene wax, 3-10 parts of magnetic iron powder and 20-67 parts of diisocyanate. The diisocyanate microcapsules use the diisocyanate as a core material, and the petroleum resin/paraffin/polyethylene wax/magnetic iron powder mixture as the shell of the capsule. When micro cracks occur in the concrete, the crack propagation can break partial of the microcapsule inside, the diisocyanate inside the microcapsules flows out and diffuses into the crack and is subjected to a solidifying reaction with water in the concrete, so that the crack is repaired in time; and for the microcapsules that are not broken by cracks, external electromagnetic field can be applied to melt the shell to release the diisocyanate inside, thereby diffusing into cracks and solidify with water to repair them.

Abstract: The disclosure provides a wireless channel scenario identification method and system. The method includes: simulating different wireless channel scenarios to obtain a channel scenario baseband signal y(t)pq; extracting a feature parameter of y(t)pq, extracting an autocorrelation function Ah(t)pq and performing a Fourier transform thereon to obtain a power spectral density function S(t)pq; normalizing S(t)pq to obtain a normalized channel scenario power spectral density function S(t)pq; designing a deep learning network and inputting S(t)pq and a category label pair to train the deep learning network; and for a system with a channel scenario to be identified, collecting a passband signal at its receiving end, obtaining the normalized scenario power spectral density function ?(t)pq, and using ?(t)pq as an input of the trained classifier, the output of the classifier being a label sequence of the channel scenario, and the channel scenario is effectively determined.

Abstract: Provided are a failure diagnosis method and apparatus for open circuit failure of a power tube of a three-phase rectifier based on a current signal, relating to a failure diagnosis technique for power electronic equipment and capable of quickly and accurately diagnosing on an open circuit failure of the power tube of the three-phase rectifier without adding a hardware component. The failure diagnosis method only requires a sampled current existing in the control system of the rectifier and some intermediate computing signals and is therefore simple and requires little computing resource. A distorted current after the open circuit failure occurs in the power tube of the rectifier and a positive/negative half cycle where the current is present when the failure occurs serve as diagnostic variables. By analyzing the sampled current, a quick diagnosis on the power tube having the open circuit failure is provided. Thus, the invention is highly applicable.

Abstract: The present disclosure relates to a compound and a preparation method and application thereof, the compound having a chemical structure formula of: wherein M in the formula is selected from a group consisting of CF3 or CF2H, and R1, R2, and R3 are each independently selected from a group consisting of aryl, heteroaryl, and alkyl. The compound provided by the present disclosure can be used as a trifluoroethanolation reagent or difluoroethanolation reagent as synthetic intermediates of many organic compounds, and some of the compounds have pharmaceutical activity. The preparation steps of such compounds are simplified, with mild synthesis conditions and wide applicability of substrates.