Abstract: The present invention relates to the technical field of high-gain DC-DC converters, and disclosed is a high-gain quasi-resonant DC-DC converter based on a voltage doubling rectifier circuit. On the basis of a half-bridge quasi-resonant high-gain circuit topology and by combining a bidirectional positive and negative voltage doubling rectifier circuit, the present invention provides a high-gain DC-DC converter. The converter can further improve output voltage gain and reduce output voltage ripples, and can improve the system efficiency while reducing the number of turns of a high-frequency transformer; moreover, the converter can achieve soft-switching control, thereby having the advantages of low voltage and current stress, high efficiency, and the like.

Abstract: A platform, system, and method for simulating critical rock collapse of surrounding rock in underground engineering includes: four vertically arranged reaction walls defining a square reaction space, and a base mounted at a lower end opening of the wall; and a row of horizontally arranged stress loading plates at a side of each wall close to the reaction space, and a reaction beam above this space, where the reaction beam, the stress loading plate, and the base define a loading space, and the loading space is configured for placement of a surrounding rock simulation block to be tested; the stress loading plate capable of moving horizontally in a direction of the reaction wall, and the reaction beam capable of moving in a vertical direction, so as to load the surrounding rock simulation block; and the stress loading plate and the reaction beam being driven by linear motion units for movement.

Abstract: A horizontal jet-mechanical combined rock breaking test device and method. The device includes a horizontal base. One end of the horizontal base is provided with a multi-mode cutter head. A jet-mechanical combined cutter is provided on the multi-mode cutter head. The other end of the horizontal base is provided with a surrounding rock stress simulation bin for loading a rock sample. The multi-mode cutter head is connected to a driving mechanism, and the multi-mode cutter head is configured to advance and rotate horizontally along the horizontal base under the action of the driving mechanism, so that the jet-mechanical combined cutter is capable of acting on the rock sample.

Abstract: Disclosed is a magnetically controlled material-based magnetorheological pilot operated safety valve for a hydraulic support. The safety valve comprises a valve body, a valve core, a reset spring, and a pilot valve; the valve core is disposed in a valve core chamber provided in the valve body, and the pilot valve is disposed in a pilot valve chamber provided in the valve body; the pilot valve includes a magnetically controlled shape memory alloy, an electromagnet, a push rod, a piston, a magnetorheological fluid control coil, and a pilot valve core, which are arranged sequentially from left to right; a plurality of magnetically controlled material control coils are provided on the electromagnet; the magnetically controlled shape memory alloy runs through the electromagnet and is then connected to the push rod, the push rod is connected to the piston, the magnetorheological fluid lies between the piston and the pilot valve core.

Abstract: The present invention relates to the technical field of gene engineering and particularly relates to a method for constructing non-de novo synthesized Mucor circinelloides recombinant strain with high lipid yield, recombinant strain constructed by method, and application of recombinant strain. According to the present invention, a diacylglycerol acyltransferase gene (DGAT) is overexpressed in Mucor circinelloides WJ11 by a homologous recombination technology, and exogenous oil is added for fermentation, such that the non-de novo synthesized Mucor circinelloides recombinant strain with high lipid yield is constructed. Compared with the control strain Mc2075, the fat yield of the Mucor circinelloides is increased; and when the diacylglycerol acyltransferase (DGAT) is transformed into the uracil defective type of Mucor circinelloides WJ11, the fatty acid composition changes after fermentation, and the lipid content may reach 53% of dry cell weight after the fermentation condition is optimized.

Abstract: A predicting system and method for the uniaxial compressive strength of rock include a point loading strength test module, a longitudinal wave velocity test module, a rock rebound value test module and a strength prediction module, wherein the longitudinal wave velocity test module performs longitudinal wave velocity tests on the rock, and transfers the longitudinal wave velocity of the rock to the strength prediction module; the rock rebound test module performs rebound test on the rock, and transfers the rebound value of the rock to the strength prediction module; the point loading strength test module performs image acquisition on a fracture surface of the rock after being loaded and fractured by the point loading test, and calculates the area of the fracture surface; and the strength prediction module outputs a uniaxial compressive strength prediction result of the rock according to the received information and a preset prediction model.

Abstract: The present disclosure provides a method for controlling an amount of silicon added to ductile cast iron, a method for casting ductile cast iron, and a cast product, which relate to the technical fields of metallurgical and cast iron alloys. The method for controlling an amount of silicon added to ductile cast iron includes smelting ductile cast iron using scrap steel as a raw material. After the scrap steel is melted into molten iron, a copper alloy is added so that the molten iron has a copper equivalent of 0.8% to 1.0%, wherein the copper equivalent is controlled by formula (II). Then, ferrosilicon is added so that the content of silicon added to the molten iron satisfies formula (I).

Abstract: An RNA fluorescent probe for rapidly distinguishing cancer tissue from normal tissue based on nucleolar morphological changes, the probe being (E)-1-(3-aminopropyl)-4-(2-(9-ethyl-9H-carbazol-3-yl)vinyl)pyridine-1-ium dibromide, abbreviated as CAPY-AP. The probe can target RNA in culture cells and normal tissue as well as cancer tissue and then display nucleolar morphology. The judging criteria of distinguishing the cancer tissue from the normal tissue based on the nucleolar morphological changes is only single and unconspicuous nucleolus in most cells of normal tissue, while the enlarged nucleoli and/or multiple nucleoli exist in many cells of cancer tissue. Compared with other existing RNA probes, the probe has super-high RNA affinity and super-high permeability, and can rapidly image the RNA and nucleoli in tissue sections.

Abstract: A multi-wavefield seismic detection method and system based on construction noise of a shield machine. Multi-wavefield seismic information such as a body wave and a surface wave formed during propagation of a seismic wave generated by excitation in a stratum is obtained by using noise information caused by the construction of a shield machine as a seismic source, a stratum velocity model along a tunnel is constructed through joint inversion, and reflection wave information or the like is used for migration imaging, to eventually implement relatively accurate detection of a geological condition in front of a tunnel face of shield construction.

Abstract: The present invention discloses an opposite belt-type precise seeding device. The opposite belt-type precise seeding device comprises a seed metering tube consisting of a U-shaped shell and a cover plate, two conveying devices provided inside the seed metering tube in parallel, and a conveying plate provided at the lower end of the seed metering tube. The opposite belt-type precise seeding device belongs to the field of agricultural machinery. In a seeder, a tubular seed conveying tube is usually used for guiding movement of seeds, but the movement of the seeds in the seed conveying tube has certain randomness, so that the seed distance consistency of the seeds in a seed bed is reduced. Through control of the seeds by the conveying devices, the stable movement of the seeds is achieved and the seed distance consistency of the seeds in the seed bed is guaranteed.

Abstract: An on-line quantitative evaluation method for the stability of a welding process includes the steps of monitoring and acquiring the arc voltage U and the welding current I during the welding process, and drawing a phase diagram of each U-I cycle; converting the phase diagram of each U-I cycle into a binary image K; obtaining an area JN through which a dynamic working curve passes in the binary image K; obtaining a welding process stability evaluation index P according to the formula (1), where JN is the area of a U-I curve, N is the number of cycles passed, L is the total number of samples in N cycles, and P is the repetition rate of the i-th U-I cycle and other cycles (i=1 . . . N); and evaluating the stability of the welding process according to the obtained welding stability evaluation index P.

Abstract: A communication compression method based on model weight distribution in federated learning, and belongs to the technical field of wireless communication. Based on the existing federated average idea in federated learning, counts the distribution of model weight information to be transmitted between nodes during each communication, then performs scalar quantization and compression through Lloyd-Max quantizer according to their distribution characteristics, then encodes with Huffman coding method, and finally sends the codes to the target node, thereby the minimum mean square quantization error is realized and the number of bits required for communication is reduced.

Abstract: The present invention relates to the field of chemical analysis detection and application, in particular to a marker peptide of snake venom thrombin-like enzymes (SVTLEs) from Agkistrodon Halys Pallas and an application thereof. The amino acid sequence of the marker peptide of snake venom thrombin-like enzymes (SVTLEs) from Agkistrodon Halys Pallas is TLCAGVMEGGIDTCNR. Characterizing the source of species and a content of the SVTLEs in a to-be-detected sample by using the marker peptide includes the following steps of: pretreating the to-be-detected sample by trypsin through enzymolysis, and taking a supernatant of an enzymolysis liquid as a test solution; and injecting the test solution and a reference solution into a liquid chromatography-mass spectrometer, and selecting a qualitative ion pair and a quantitative ion pair for detecting the source of species and a content of the SVTLEs in the to-be-detected sample.

Abstract: The present disclosure provides a determining device for the weathering resistant capability of clastic rocks in a tunnel based on feldspar features, which overcomes the shortcomings of current evaluation methods, is easy to operate, can be used to detect the type, content, and crystal structure of feldspar in a rock stratum, and integrates the information by combining a computer deep learning method to determine the weathering resistant capability of clastic rocks containing different types of feldspar in a tunnel, with high accuracy.

Abstract: A discrete element method contact model building method includes: selecting a filling body in a disaster-causing structure to obtain a change rule of cumulative loss of the filling body ; performing test simulation, and determining a relation function of each group of corresponding mesoscopic mechanical parameters in each time period and mesoscopic parameters of a DEM contact model representing a change rule of macroscopical parameters of the filling body; embedding each mesoscopic parameter relation function into an existing particle contact model, performing test simulation, and updating a fracture failure criterion of the contact model according to a corresponding relation of macro-mesoscopic strength during model failure; and based on a seepage failure indoor test, building a seepage failure discrete element calculation model, and simulating the seepage failure process of a rock and soil mass by using the obtained particle contact model and the fracture criterion of the particle contact model.

Abstract: The present disclosure discloses an abrasive water jet full-section cutting type cutter head and application devices. The cutter head includes a cutter head body and a rotor eccentrically arranged on a working surface of the cutter head body. The rotor revolves with the cutter head body and also rotates about its own axis. At least one first nozzle is arranged on an edge of a working surface of the rotor. At least one group of second nozzles and at least one third nozzle are arranged on the working surface of the cutter head body, and the second nozzles and the third nozzle cooperate during the rotation of the cutter head body and the rotor, then a material to be cut is cut into a plurality of concentric rings, and the first nozzle cuts off the ring material to form fragments.

Abstract: A system for navigation detection and inclination measurement of advanced hydraulic supports, including a detection device module, a signal transfer transmission module, connected to the detection device module, and used to integrate ultrasonic signals and inclination signals received from all advanced hydraulic supports and then wirelessly transmit all the signals to an analysis and processing module. The analysis and processing module, connected to the signal transfer transmission module, and used to receive the signals from the signal integration and transmission device for analysis, where if an analysis result shows an abnormal situation, an alarm will b e immediately given to a worker. If the analysis result shows a continuous abnormal situation, or a relatively large value indicating the abnormal situation is generated, a command will be immediately sent to make the advanced hydraulic supports stop operating in a current mode.

Abstract: A three-dimensional electrical resistivity tomography method and system belonging to the field of geological geophysical prospecting, the method including the steps of prospecting a region containing a geological anomaly with at least two prospecting modes respectively to acquire two-dimensional resistivity data of a corresponding detection plane; unifying coordinate systems of resistivity data points acquired in all prospecting modes, and extracting data points with the same coordinates; carrying out data fusion on extracted resistivity data at the same position by utilizing a principal component analysis method; and carrying out three-dimensional coordinate conversion on resistivity data acquired after fusion to form a three-dimensional model.

Abstract: A method and system for generating a logarithmic non-uniform pseudo-random electromagnetic exploration signal including: constructing two or more basic unit signals, according to an exploration requirement, that are stairstep signals obtained by superposing in-phase periodic square wave signals, a frequency ratio between adjacent periodic square wave signals is 2, and the two or more basic unit signals meet the following requirement: if a lowest dominant frequency in a first basic unit signal is a fundamental frequency, lowest frequencies of the remaining basic unit signal are l×2m times the fundamental frequency, where l is an odd number except 1, and m is a natural number; and superposing the two or more basic unit signals to obtain a logarithmic non-uniform 2n sequence pseudo-random signal. A logarithmic non-uniform 2n sequence stairstep signal is constructed within a limited frequency interval, and requirements of prospectors for a higher frequency density within a specific frequency interval are met.

Abstract: A red mud utilization method based on co-processing of industrial exhaust gas, sewage treatment and an environment-friendly and high-performance civil functional material, belongs to the technical field of environmental science and cementitious material preparation, and relates to a preparation process of a solid waste-based cementitious material, specifically including the steps: preparing an environment-friendly and high-performance red mud-based civil functional material by using slag obtained after sewage treatment with red mud and other solid wastes in physical and chemical activation and high-temperature calcination methods. The compressive strength of a solid waste-based cementitious material prepared by using the method can reach 29 MPa, the leaching quantity (lower than 3.0 ppm) of toxic elements such as heavy metals is far lower than the national standard requirement, and a solid waste-based cementitious material with great performance can be prepared.