Abstract: The present invention discloses a piezoelectric patch-based real-time and high-precision bolt preload detection method and system. A piezoelectric patch is used as an ultrasonic excitation source and pasted on the head of a bolt, and the high-precision fitting relationship between the ultrasonic change of time-of-flight and the bolt preload is established according to the law of the ultrasonic change of time-of-flight of single echo with the stress so that the real-time detection of the bolt preload is realized by using the mathematical relationship. Compared with the previous method using ultrasonic probes, the present invention eliminates the error caused by the uncertainty of couplant thickness and further improves the measurement precision by using the change of time-of-flight of single echo. Meanwhile, the low-error rate measurement of the bolt preload is realized at a low cost and without affecting the structural performance.

Abstract: The present invention provides a method for an optimal scheduling decision of an air compressor group based on a simulation technology, which belongs to the technical field of information.

Abstract: A rapid detection method for the geometric accuracy of the linear motion axis of an NC machine tool, uses accelerometers to measure the acceleration perpendicular to the direction of motion when the linear motion axis moves at a uniform speed. Firstly, the measuring device is mounted on the linear motion axis, and the upper measurement system automatically performs multi-channel acquisition and storage of the motion point acceleration data. Then, filter the acceleration data at the different speeds. Finally, the displacement data is obtained by quadratic integration of the filtered acceleration data in the time domain. Then calculate the straightness of the linear motion axis using the End Point Fit method, and complete the rapid measurement of the straightness of the linear motion axis of the machine tool. This can realize the rapid measurement of the geometric accuracy of the linear motion axis of the machine tool.

Abstract: A method for prediction of key performance parameters of an aero-engine in transition condition. Bench test data for an aero-engine in transition condition provided by a research institute is used for establishing a training dataset and a testing dataset first; parameter combination is used for predicting and analyzing engine exhaust temperature based on the idea of information fusion; and the method of rolling windows is used for rolling learning in order to predict the parameters such as low pressure rotor speed and exhaust temperature of an engine from the perspective of practical engineering application.

Abstract: A reference-level gear helix artifact for transferring gear helix value. The invention provides a reference-level gear helix artifact with a global symmetrical structure that can be easily obtained by generating method. The centroid point of the artifact passes through the geometric center of the artifact mandrel. The cylinder of the reference-level gear helix artifact is provided with the straight tooth groove, the left-hand tooth groove and the right-hand tooth groove, axial reference torus and radial reference cylinder, fine tooth threads and center holes. Among them, the straight tooth groove includes a pair of involute cylindrical surfaces with opposite 0° helix angle, the left-handed tooth groove includes a involute helicoidal surface with 15° and a involute helicoidal surface with 30°, and the right-hand tooth groove includes a involute helicoidal surface with 15° and a involute helicoidal surface with 30°.

Abstract: An active tuned mass damper applied to the offshore monopile wind turbine belongs to the field of marine technology. A mass block is connected to the inner wall of the tower through a spring. The two ends of the damper and the force actuator are connected to the mass block and the inner wall of the tower, respectively. When the installation of tower is finished, the spring and the damper begin to work. The movement of mass block will partly offset the movement of the tower caused by the wave force. The force actuator starts to work before the mating. The exact position of the nacelle can be obtained from the Global Positioning System (DGPS). The position of tower can be adjusted in the horizontal plane through the force actuator. So, the offshore installation time for nacelle will be saved. The whole installation time and cost will also be reduced.

Abstract: The disclosure relates to a method for fermentation integrated with separation and purification of acetone, butanol, and ethanol (ABE) or butanol alone, comprising the following steps: 1) obtaining ABE by fermentation using an acetone-butanol-producing bacterium or obtaining butanol using a butanol-producing bacterium; 2) using a “vapor-stripping-vapor-permeation” method (briefly VSVP) for online separation and purification of ABE or purifying butanol from the fermentation broth; wherein the VSVP method comprises the following steps: introducing a gas bubble into the fermentation broth comprising active cells for fermentation to vaporize ABE or Butanol; subjecting the gas along with the vaporized ABE or Butanol to a membrane separation unit to pass through the membrane; recovering ABE or Butanol, or subjecting ABE or Butanol to a next separation device.

Abstract: A digital image measurement device and method for the surface deformation of specimen based on sub-pixel corner detection is disclosed. This digital image measurement device is composed of a new type of image pressure cell, a complementary metal-oxide-semiconductor (CMOS) camera, a camera bracket, a flexible lens hood, a computer and matching measurement software. This method discretizes the specimen into several four-node finite elements by printing grids on the specimen and takes corners of the grids as the nodes of the finite elements; tracks the deformation of the feature points in real time by edge detection and corner detection based on sub-pixel; captures the deformation of the whole surface of the specimen by the two flat mirrors which are at an 120° angle behind the specimen; achieves the observation of the deformation of the whole surface by conducting splicing and error correction on the three images.

Abstract: A magnetofluid pump device for IGBT heat dissipation and a test method therefor are provided. The magnetofluid pump device uses a liquid metal as a coolant, which can absorb more heat than an ordinary water-cooling device and better dissipate heat for IGBT chips. Temperature and pressure changes in an inlet pipe and an outlet pipe of a magnetofluid pump can be monitored in real time through temperature sensors and pressure sensors, and temperature changes of the IGBT chips can be observed in real time through a thermal imager. The test method for the magnetofluid pump device for IGBT heat dissipation proposed by the present invention is simple and easy to implement. A magnetic fluid can be driven to flow by energizing positive and negative electrodes in the magnetofluid pump under the action of magnetic fields, and water-cooling equipment can dissipate heat for the magnetic fluid in the magnetofluid pump.

Abstract: A prediction method for mold breakout based on feature vectors and hierarchical clustering is disclosed, which comprises: respectively extracting temperature feature vectors of historical data under sticking breakout and normal conditions and on-line actually measured data to establish a feature vector sample set; performing normalization and hierarchical clustering on the sample set; and checking and judging whether the feature vectors extracted on line belong to a breakout cluster, and then identifying and predicting mold breakout.

Abstract: A thermal extrusion method to fabricate large-dimension superhydrophobic cylinder pillar arrays with droplet pancake bouncing phenomenon. Preparing thermal extrusion mold: the through-hole arrays with 0.8˜1.25 mm diameter, 0.25 mm interval space and 0.6˜1.0 mm height are first obtained on metals, and are then polished, rinsed and dried. Thermal extrusion: polymer materials are first thermally extruded on the obtained mold and cooled to room temperature. Demold: excess polymer materials flowing from the through hole are cut off and then the polymer cylinder pillar arrays are lifted off from the mold. Superhydrophobic treatment: the whole polymer sample is treated using mixed liquid spray consisting of titanium oxide nanoparticles dispersed in fluoroalkylsilane ethanol solution, and the superhydrophobic cylinder pillar arrays are obtained.

Abstract: A method of in-situ TEM nanoindentation for a damaged layer of silicon is disclosed. Wet etching and ion beam lithography are used for preparing a silicon wedge sample. An etched silicon wedge is thinned and trimmed by a focused ion beam; thinning uses ion beam of 30 kV: 50-80 nA, and trimming uses ion beam of 5 kV: 1-6 pA; and the top width of the silicon wedge is 80-100 nm. The sample is fixed on a sample holder of an in-situ TEM nanomechanical system by using a conductive silver adhesive. The sample is indented with a tip in the TEM, so that the thickness of the damaged layer of the sample is 2-200 nm; and an in-situ nanoindentation experiment is conducted on the damaged layer of the sample in the TEM.

Abstract: A passive heave compensator, including an elastic cable, an electromagnetic damping device, a cylindrical sector, and a disc damping plate. The electromagnetic damping device includes a first cylinder including a helical coil, a permanent magnet mechanism disposed in the first cylinder, a first cover plate, a second cover plate, a first sliding shaft, a second sliding shaft, a first spring, a second spring, a first end cover, and a second end cover. The cylindrical sector includes a roof plate, a middle plate, a base plate, a first side plate, a second side plate, and a curved plate. The disc damping plate is disposed around the middle plate of cylindrical sector. The elastic cable is directly connected to the electromagnetic damping device. The electromagnetic damping device is disposed in the central part of the cylindrical sector. The middle plate is disposed between the roof plate and the base plate.

Abstract: A device for fixing a cylinder, the device including a first outer casing; a rotatable inner casing; a second outer casing; a plurality of curved blades; and at least one transmission. The second outer casing is in threaded connection to the first outer casing, and includes a first bearing, a second bearing, a third bearing, a first division plate including a first through hole and a first arc groove, and a second division plate including a second through hole and a second arc groove. Each curved blade includes a first connection rod having a ball head, a second connection rod pivotally connected to the first connection rod via the ball head, and a slot. The at least one transmission includes a gear shaft, a first ring gear, a first pinion, a second ring gear, a second pinion, and a shaft pin.

Abstract: A method for calculating axis deviation of rotor assembly based on end face runout measurement comprises three parts: calculation of three contact points, a triangle judgment criterion and a homogeneous coordinate transformation algorithm of a deviation matrix. Based on the measured end face runout data in production practice, the method realizes the prediction of axis deviation before assembly, improves the concentricity of rotors after assembly, also greatly increases the one-time acceptance rate of assembly and has important practical guiding significance for axis prediction as well as assembly phase adjustment and optimization in the assembly process of aero-engine rotor pieces.

Abstract: A mutual-lapping device and mutual-lapping method for improving processing precision based on the principle of error averaging is proposed. The device including driving friction wheel, driving belt pulley, transmission belt A, connecting rod A, rotation shaft segment A, multi-ball sleeve, mutual-lapping gear A, tension spring, driven friction wheel, pendulum bar of the driven friction wheel, driven belt pulley, transmission belt B, connecting rod B, pressure spring of tensioning pulley, tensioner mechanism, rotation shaft segment B and mutual-lapping gear B. By mutual lapping the high-precision gears, not only the pitch deviation, tooth profile deviation, helix deviation and runout can be reduced synchronously, but also the machining cost is low. Meanwhile, the effect of improving pitch accuracy, profile accuracy, helix accuracy and runout accuracy and reducing surface roughness is remarkable.

Abstract: A method for preparing a large-area structural chromogenic pattern by ink-jet printing, a structural chromogenic pattern obtained by the method, and an anti-counterfeiting method based on a structural color change. A dispersion liquid containing mono-disperse colloidal microspheres with high index of refraction is printed onto a piece of paper by using an ink-jet printer, and nano-microspheres are arranged and assembled on the paper to obtain a micro-structure having the features of being ordered from a short distance and disordered from a long distance. A pretty structural color can be observed by means of the interaction of the structure with light, thus displaying a pattern, changing the angle of observation, changing the brightness of the structural color, and hiding and displaying the pattern. The method is simple and convenient, is widely applicable, and can achieve the preparation and anti-counterfeiting of a large-area structural color without external stimulation.

Abstract: An ultrasonic testing device and method for the connection force of interference fit. The motion control module can realize accurate positioning for the interference fit part and accurate control for motion in the circumferential direction and the axial direction; scanning increments of the circumferential direction and the axial direction are set, and the motion control module drives the interference fit part to perform circumferential and axial point scanning until the testing of the whole matching surface is completed. The ultrasonic signal measured by the point focusing water immersion probe is transmitted to a PC through a control loop in the testing process. Then the stress distribution of the matching surface is obtained through the relationship between the ultrasonic signal and contact stress Finally, the size of the connection force is calculated according to the static friction coefficient.

Abstract: A mass spectrum resolution device for measuring laser ablation ion species with improved time of flight mass spectrometry includes a vacuum system unit, a plasma production unit, and a particle restraint selection and separation unit, wherein the particle restraint selection and separation unit comprises a particle limit selector and a plurality of ion pulse accelerated electrode plates; the particle limit selector comprises a restrainer lifting block, a restrainer and a restrainer selection baffle; a through hole is formed in the restrainer lifting block; a plurality of circular holes with different apertures are formed in the restrainer selection baffle, and the restrainer and the restrainer selection baffle are arranged in the restrainer lifting block and can move; and the ion pulse accelerated electrode plates are arranged in the advance direction of particles and are axially parallel to the restrainer lifting block.

Abstract: A method for directly planning a reentry trajectory in a height-velocity profile includes the following steps: S1, extracting an actual working parameter of an aircraft, setting the maximum value {dot over (Q)}max of a stagnation point heat flux, the maximum value qmax of dynamic pressure, and the maximum value nmax of overload according to the mission requirement, and solving the height-velocity boundary of the reentry trajectory, that is, a lower boundary of the reentry trajectory in the height-velocity profile; S2, solving a reentry trajectory of an initial descent stage according to differential equations of reentry motion, and determining a starting point of a trajectory of a gliding stage according to the trajectory of the initial descent stage; and S3, planning a trajectory in the height-velocity profile satisfying terminal constraints based on the lower boundary in the height-velocity profile, and calculating a corresponding bank angle, to obtain the reentry trajectory.