Abstract: A performance test bench device for a centrifugal compressor under a variable working condition of an engine is composed of: a turbine back disk temperature simulator and the centrifugal compressor being coaxially arranged, and being sequentially connected with a speed regulator and a driver. Meanwhile, a thermocouple array is arranged on a surface of a simulator back plate. A temperature measurement probe is arranged at an inlet and an outlet of the centrifugal compressor, and a thermocouple array is also arranged on a surface of a cover plate of the centrifugal compressor and a surface of a rotating blade. An airflow passes through the inlet pipeline, the flow meter and the air inlet rectification system, is pressurized by the centrifugal compressor, and is then discharged by the outlet pipeline.

Abstract: A detection device includes a frame body and a main pipe positioning assembly, a branch pipe positioning assembly, and a first driving assembly disposed on the frame body. One side of the frame body is provided with an opening. The branch pipe positioning assembly is disposed inside the opening. The first driving assembly adjusts the branch pipe positioning assembly, so that the branch pipe positioning assembly is adapted to positions of the two branch pipes. During detection, the branch pipes are located in the opening, the main pipe positioning assembly connects two ends of the main pipe, and the branch pipe positioning assembly connects the two branch pipes. Two limiting members are slidably disposed on the frame body to open and close the opening, and the limiting members abut against an outer wall of the main pipe, such that the main pipe is located inside or outside the opening.

Abstract: The present disclosure provides a drain-gate voltage excitation and source-drain current acquisition system and method for gas-sensitive organic field effect transistors (OFETs). The system includes an acquisition device and a gas-sensitive OFET array. The device includes a microcontroller module, a power supply management module, a voltage excitation module, a voltage regulation module, a transimpedance amplifier (TIA) module, a fully-differential low-side current detection module, a voltage acquisition module, a signal transmission module and an array switching module. In the present disclosure, the real-time monitoring of various harmful gases and the performance testing of the gas-sensitive OFETs are realized. The device has two current detection modes, thereby not only stabilizing drain electric potentials, but also enabling drain-source currents to be measured with sufficient accuracy.

Abstract: A welding method for improving quality of 5G all-position welding of a marine riser and a product thereof are provided, and the disclosure belongs to the technical field of welding. The welding method specifically includes the following. welding the marine riser in 5G all positions using a unified welding mode; reducing a predetermined voltage or reducing predetermined inductance in an overhead welding position to improve directivity and stability of an arc; and meanwhile increasing an arc swing width in the overhead welding position to eliminate a lack-of-fusion defect. In the disclosure, a unified welding mode suitable for flat welding is applied to marine riser welding. The process of 5G all-position welding of the marine riser is effectively simplified. The welding quality of 5G all-position welding of the marine riser is thereby effectively improved.

Abstract: A simplified method for welding a 5G position filler layer of a marine riser and a product thereof are provided, and the disclosure belongs to the technical field of welding. The method specifically includes the following. performing filler welding on the marine riser using an oscillation scanning laser-GMAW hybrid welding process; performing welding on each layer using same process parameters, then reducing gravity of a molten pool and increasing an arc force through interaction between laser and an arc, meanwhile expanding a range of a welding molten pool through an oscillation scanning behavior of the laser beam. A lack-of-fusion defect is prevented from being generated. A 5G position filler layer welding process of the marine riser is effectively simplified in the disclosure. Further, laser beam scanning also expands the range of the welding molten pool and prevents generation of the lack-of-fusion defect on a side wall.

Abstract: A method for determining the filling welding parameters of large deformation pipeline steel based on secondary regulation method includes: welding specimens to be welded for secondary welding thermal simulation experiments based on a thermal simulation to obtain samples after thermal simulation; processing the samples after thermal simulation into CTOD samples and calculating fracture toughness parameters; pre-loading of specimens requiring pre-strain after thermal simulation by uniaxial tension, and then processing samples before and after pre-strain after thermal simulation, conducting slow strain rate tension tests and calculating stress corrosion cracking susceptibility parameters; comparing the change in elongation of the samples before and after pre-strain and calculating the pre-strain sensitivity parameters; determining secondary thermal simulation parameters; converting the secondary thermal simulation parameters into welding heat input parameters; determining welding parameters based on welding heat

Abstract: Biomimetic nacre-toughness cement slurry based on in-situ polymerization of a fluid loss additive, a preparation method and an application thereof are provided. The preparation method includes: dissolving 2-acrylamido-2-methylpropane sulfonic acid monomer and carboxylic acid monomer in deionized water, adjusting pH to 5.5-6.5, then adding an acrylamide monomer, and uniformly stirring to obtain a monomer solution; adding an initiator and a catalyst into the monomer solution, and then stirring to obtain a pre-polymerization solution; adding cement particles into the pre-polymerization solution under low-speed stirring, and then performing high-speed stirring to obtain the biomimetic nacre-toughness cement slurry. The obtained cement slurry can optimize a microstructure of cement while possessing a well capacity for controlling fluid loss, improve deformation ability and toughness of a cement sheath, and effectively improve brittleness defect of the cement sheath.

Abstract: A cylinder gas recirculation system device of an internal combustion engine based on pressure differential driving is provided, the overall device includes a recirculation intake and exhaust system and a gas storage system. An intake control valve on a cylinder block, a surge tank, and an exhaust control valve on the cylinder block are sequentially connected to form a gas recirculation subsystem of the cylinder block of the internal combustion engine. Two adjacent subsystems are in communication through an intake pipe. Positions of intake and exhaust pipelines may be anywhere between the top and bottom dead centers of a piston in a cylinder, and intake and exhaust valves of the gas recirculation may share the same valve. Different valves may also be used, and the intake and exhaust pipelines of the gas recirculation are arranged on the same side of the cylinder in double layers.

Abstract: The present disclosure relates to a method and system for predicting the critical floating time of a reinforcing phase. According to the method, a particle concentration processing model, a half-life processing model, an agglomeration kinetics model, and a floating time processing model are combined to obtain the critical floating time of a reinforcing phase particle according to an initial particle size of the reinforcing phase particle, a density of the reinforcing phase particle, a mass fraction of the reinforcing phase of a composite soldering material, and a density of the composite soldering material. The method and system can accurately predict the critical floating time of the reinforcing phase particle.

Abstract: A learning-based active surface model for medical image segmentation uses a method including: (a) data generation: obtaining medical images and associated ground truths, and splitting the sample images into a training set and a testing set; (b) raw segmentation: constructing a surface initialization network, parameters of the network trained by images and labels in the training set; (c) surface initialization: segmenting the images by the surface initialization network, and generating the point cloud data as the initial surface from the segmentation; (d) fine segmentation: constructing the surface evolution network, the parameters of the network trained by the initial surface obtained in step (c); (e) surface evolution: deforming the initial surface points along the offsets to obtain the predicted surface, the offsets presenting the prediction of the surface evolution network; (f) surface reconstruction: reconstructing the 3D volumes from the set of predicted surface points set to obtain the final segmentatio

Abstract: The present invention belongs to the bioengineering field, and relates to a method for fermentation production of L-theanine by using an Escherichia coli genetically engineered bacterium. The engineered bacterium is obtained by serving a strain as an original strain, wherein the strain is obtained after performing a single copy of T7RNAP, a dual copy of gmas, xylR knockout, and sucCD knockout on an Escherichia coli W3110 genome, and by integrating genes xfp, pta, acs, gltA, and ppc, and knocking out ackA on the genome. The present invention has a high yield, and stable production performance; after 20-25 h, L-theanine has a titer of 75-80 g/L, and the yield is up to 52-55%. The fermentation broth is purified by membrane separation in combination with a cation-anion resin series technique. Moreover, the one-step crystallization yield is 72.3% and the L-theanine final product has a purity of 99%.

Abstract: The present disclosure provides a treatment method for oily sludge and a method for soil remediation. The treatment method for oily sludge includes: mixing the oily sludge with target biochar uniformly according to a first preset mass ratio, and conducting catalytic pyrolysis at a first preset temperature to achieve efficient removal of petroleum hydrocarbons, to obtain a pyrolysis residue used for soil remediation. In the present disclosure, the method realizes resource utilization and harmless utilization of the pyrolysis residue.

Abstract: The disclosure discloses a creep lifetime prediction method for a P92 main steam pipeline welded joint, which includes the following. Based on the minimally invasive sampling technology and the microstructure characterization equipment, the microstructure of the P92 steel welded joint after service is obtained. An area with a most significant degradation of the P92 steel welded joint is determined by performing grading processing on the microstructure of the welded joint. The maximum main stress of the structural component is obtained through the finite element technology and the actual service pressure of the P92 steel welded component. Through the maximum main stress and the microstructure after grading, based on the temperature-related Larson-Miller creep lifetime prediction method, the creep lifetime of the welded joint under the condition is determined.

Abstract: A method for treating a waste plastic based on a persulfate system is provided. The method includes the following steps: mixing the waste plastic, sulfuric acid, sulfate, peroxymonosulfate, and water, and reacting at 80-140° C. for 3-15 h to complete the treatment; where the waste plastic is polyethylene or polyethylene terephthalate; and the sulfate is copper sulfate or ferrous sulfate. The present invention reasonably regulates and controls each parameter in the reaction process while constructing a homogeneous catalysis system of transition metal activated peroxymonosulfate, and finally directionally converts the waste plastic into C7H12 and C10H12 fuels, which realizes high-efficiency recycling of the waste plastic, has a simple and convenient working procedure, and has a wide application prospect.

Abstract: A method of analytical calculation of power supply reliability indexes of a power distribution network includes (A1) acquiring parameters of the power distribution network; (A2) building a reliability calculation model, which includes treating the power distribution network as a node-branch calculation unit and numbering nodes and branches in the power distribution network; (A3) building correlation matrices, and calculating a power supply path matrix and a tie-line matrix, wherein the correlation matrices are a node-branch association matrix, a section switch matrix and a fuse matrix; (A4) deriving a fault incidence matrix through the power supply path matrix, the section switch matrix, the fuse matrix and the tie-line matrix, and calculating the reliability indexes of the nodes and the power distribution network; and (A5) identifying vulnerable links by performing sensitivity analysis through partial derivative transformation for quantifiable parameters or perturbation transformation for unquantifiable para

Abstract: A bilevel coordinated optimization method for fixed and mobile charging facilities on highways, includes: constructing an optimization model framework which includes an upper-layer coordinated location optimization model and a lower-layer coordinated capacity optimization model, where the upper-layer coordinated location optimization model is used to optimize locations of charging stations and determine locations and time points of charging demands that require truck mobile charger (TMC) deployment, while the lower-layer coordinated capacity optimization model is used to optimize TMC and fixed charger (FC) capacities at candidate sites, improving an utilization rate of FCs; and performing equivalent linearization on a nonlinear problem using a big-M method and converting the problem into a mixed-integer linear programming model, and implementing a data exchange process between upper and lower layers using analytical target cascading.

Abstract: A sponge-based variable-stiffness support structure for natural orifice surgical instrument is to support the surgical instrument and includes: a variable-stiffness sponge pipeline connected with the natural orifice surgical instrument and configured to support the natural orifice surgical instrument in a natural orifice; a hydrophobic breathable film attached to an outer wall of the variable-stiffness sponge pipeline, and configured to isolate the variable-stiffness sponge pipeline from body fluid in the natural orifice; and a gas delivery assembly connected with the variable-stiffness sponge pipeline, and configured to inject high-pressure air or water vapor into a variable-stiffness sponge pipe of the variable-stiffness sponge pipeline; wherein the variable-stiffness sponge pipeline has a stiffness inversely proportional to content of the water vapor.

Abstract: A catalytic synthesis method, a device and a system for ammonia synthesis through orderly regulation of the electronic domain of nitrogen are provided. Nitrogen and hydrogen are used as raw materials, and a multi-composition material with magnetic material as active site is used as a catalyst, thermal field, magnetic field and electric field or thermal field and electromagnetic field are applied to nitrogen, hydrogen and catalyst at the same time. The invention adopts the catalytic synthesis method, device and system for the mild ammonia synthesis at low temperature and low pressure conditions through orderly regulation of the electronic domain of nitrogen.

Abstract: The present disclosure relates to a wind farm layout and yaw control method, and an electronic device. The wind farm layout and yaw control method comprises the following steps: acquiring wind farm data, importing the wind farm data into a WFSim model for simulation, obtaining original power data of the wind farm, counting and recording modifiable wind farm layout and yaw parameters, adjusting variable parameters to be changed, using the WFSim model for simulation to obtain an optimal parameter range of different variables and combining the optimal parameters to obtain an optimal working condition, and using the WFSim model for simulation to obtain optimal power data. The wind farm layout and yaw control method according to the present disclosure is based on optimizing the power output of the wind farm, so that it is very convenient to acquired information.

Abstract: Disclosed are two system devices for stratified injecting the recirculated exhaust gas and high-specific-heat-capacity or inert gas for clean combustion of an internal combustion engine. The former is composed of an exhaust gas recirculation system, an injection system, and a power system. The latter is composed of four parts, and a high-specific-heat-capacity gas or inert gas channel is added. Injectors can be arranged at any position in the cylinder between a top dead center and a bottom dead center of a piston in a cylinder; 1-3 layers of injectors can be arranged; and 2-6 injectors can be arranged on each layer. Gas participating in combustion enters the cylinder from two intake channels, namely, a scavenging port of the internal combustion engine and the injectors; an in-cylinder swirl ratio can be remarkably increased through kinetic energy carried by the gas; and fuel-gas mixing is promoted, and the combustion rate is increased.