Abstract: The disclosure discloses a methane value online real-time monitoring system, which includes a laser tunable system portion, a gas component detection system portion and a data processing system portion. The laser tunable system portion includes a computer, laser drivers, tunable lasers, a laser beam combiner, a collimator, and a beam expander, which are connected in sequence. The gas component detection system portion includes a gas supply system pipeline, a hose, a valve, and a gas chamber. The data processing system portion includes a detector, lock-in amplifiers, an oscilloscope, and a data acquisition card, which are connected in sequence. In a working process of the methane value online real-time monitoring system, gas mass namely the methane value change can be monitored in real time on line by collecting natural gas introduced into a combustion chamber through a gas supply system pipeline of a natural gas engine.

Abstract: The present disclosure provides an apparatus for testing spray and combustion performance of an internal-combustion engine based on a rapid compression-expansion machine, which belongs to the testing field of internal-combustion engines. It includes a driving mechanism, a transmission mechanism, an engine cylinder, an air intake system and an exhaust system. The engine cylinder includes a piston, a cylinder block, a dual-fuel cylinder head and a multi-injector assembly. The piston is disposed in the cylinder block. The driving mechanism is connected with the piston through the transmission mechanism and drives the piston to linearly move back and forth along a vertical direction of the cylinder block. The dual-fuel cylinder head is connected to an upper part of the cylinder block. The multi-fuel injection assembly includes a plurality of injectors. The plurality of injectors are of the same type and are all disposed on the dual-fuel cylinder head.

Abstract: The present disclosure relates to an online monitoring method of a nuclear power plant system based on an isolation forest method and a sliding window method. An isolation forest method used in the present disclosure is an abnormal detection model based on the idea of binary tree division, and has no requirements on the dimension and linear characteristics of monitoring data. In view of the characteristics of strong nonlinearity and high dimension of operation data of the nuclear power plant system, in the process of state monitoring, system abnormalities can be detected more quickly and accurately. In the present disclosure, a sliding window method is used to improve an isolation forest model, so that the improved isolation forest model has the functions of model online updating and real-time state monitoring, and the usability of an isolation forest state monitoring method is enhanced.

Abstract: The present disclosure provides a six-cylinder opposed free piston internal combustion engine generator. The generator comprises two free piston internal combustion engine sets, one opposed piston internal combustion engine set and two linear generator sets. Air entering cylinders is subjected to first-stage compression in low-pressure cylinder sets in the free piston internal combustion engine sets and the opposed piston internal combustion engine set and then subjected to second-stage compression in high-pressure cylinder sets, and a high pressure gas produced after the combustion is subjected to first-stage expansion in the high-pressure cylinder sets and then subjected to second-stage expansion in the low-pressure cylinder sets.

Abstract: An objective of the disclosure is to provide a simulation method for a two-stage plunger pressurized common rail fuel system of a marine low-speed engine. The method includes: first setting initial status parameters, such as a control step of a system model, a total time of a calculation process, and structure parameters and pressures of components; and then establishing a mathematical model of a fuel booster unit, a mathematical model of a high-pressure fuel pipe and a mathematical model of a fuel injector based on a MATLAB simulation platform, and connecting input and output parameters of the models to realize data transfer between the models. By considering one-dimensional (1D) spatial fluctuations in the high-pressure fuel pipe, the disclosure establishes a high-precision model of the fuel system, which provides an effective method for designing and calculating detailed pressures in the common rail fuel system.

Abstract: The invention provides a method for initial alignment of radar assisted airborne strapdown inertial navigation system. By calculating the slant distance and angular position between the radar and the airborne inertial navigation equipment, a nonlinear measurement equation for the initial alignment of the radar assisted inertial navigation system is obtained. The unscented Kalman filter algorithm is used to estimate and compensate the error amount of strapdown inertial navigation system to complete the initial alignment task. The significance of the present invention is to provide an in-flight initial alignment solution when the global positioning system is limited, which has fast convergence speed and high estimation accuracy and has high engineering application value.

Abstract: A quasi-zero stiffness electromagnetic vibration isolator for ultra-low frequency vibration reduction and isolation is provided. When the vibration isolator is in a static equilibrium position, upper and lower air gaps are equal, and electromagnetic attraction forces of upper and lower stator assemblies to a mover assembly are equal. When the load tends to move upwards, the mover assembly is subjected to an upward resultant force, when the load tends to move downwards, the mover assembly is subjected to a downward resultant force, showing the characteristic of negative stiffness. A negative stiffness mechanism composed of the upper stator assembly, the lower stator assembly and the mover assembly is connected in parallel with the positive stiffness springs to achieve a quasi-zero stiffness.

Abstract: A low-noise main bearing cap for an internal combustion engine is designed that includes a main bearing cap body, wherein the main bearing cap body is connected to an engine body main bearing seat. The main bearing cap body is provided with a vibration isolator A vibration isolation structure is provided between the main bearing cap body and the vibration isolator The main bearing cap body is connected with the vibration isolator through a connector The vibration isolation structure comprises an S-shaped structure and an oil film gap, and the vibration isolator is provided with an oil inlet passage which is communicated with the oil film gap. The present design solves the control problem of the main bearing vibration source caused by the main bearing load.

Abstract: The disclosure provides an experimental calibration method of a redundant inertial measurement unit including, step (1), establishing an installation angle model using a cone descriptive scheme, and obtaining a relationship of an angular speed of a carrier and an angular speed measured by each gyroscope, step (2), establishing a standard calibration model of the redundant inertial measurement unit based on a relationship between a sensor coordinate system and a carrier coordinate system, step (3), establishing a state equation and a measurement equation of a filter, step (4), performing a row amplification of measurement amounts based on the measurement equation established in step (3), and obtaining an amplificated measurement equation for improving observability, and step (5), obtaining a Jacobi matrix and a Hessian matrix based on the amplificated measurement equation, and estimating error parameters by an extended Kalman filtering algorithm based on a second-order Taylor expansion.

Abstract: The present disclosure provides a distortion-free boundary extension method for online wavelet denoising. The method includes: S1: acquiring a signal segment xn, and performing a distortion-free boundary extension on the signal segment to obtain M+N+L data; S2: decomposing a lifting wavelet of the N data to be denoised into j layers to acquire approximation coefficients and detail coefficients; S3: calculating a threshold of each layer of the lifting wavelet; S4: thresholding the detail coefficients of each layer to obtain estimated values of the detail coefficients; S5: performing wavelet reconstruction by the approximation coefficients and the estimated values of the detail coefficients obtained by thresholding to obtain a reconstructed signal after denoising; and S6: outputting data.

Abstract: A combined ultrasonic micro-forging device and a related additive manufacturing method for improving the microstructure and mechanical properties of additive manufactured metal part. The device comprises a transducer, a pneumatic sliding table, a pneumatic sliding table connecting frame, an amplitude transformer, a tool head and a roller, wherein the transducer is provided in a transducer housing, a socket connector and a pipeline connector are provided on the transducer housing, the amplitude transformer is connected under the transducer, the tool head is connected under the transducer, the roller is located between the tool head and workpiece, and the pneumatic sliding table is connected to the transducer housing and the amplitude transformer via the pneumatic sliding table connecting frame.

Abstract: A fully variable valve train with a rotary plunger for an internal combustion engine. A motor actuates a high-pressure oil injection pump; when a timing driven electromagnetic valve connected to an oil inlet is opened, high-pressure oil enters a hydraulic cylinder; and when the force applied to a plunger by the hydraulic oil is larger than the force of a valve returning spring, the plunger is pushed to move down, so that a valve is opened. When the valve is required to be return, the timing driven electromagnetic valve connected to the oil inlet is closed, and the timing driven electromagnetic valve connected to the oil inlet is opened; the valve moves up under the action of the valve spring, pushing the plunger to move up and thereby discharging the low-pressure oil out of the hydraulic cylinder, then the plunger and the valve return to the initial positions.

Abstract: An object of the present disclosure is to provide a gas-electric parallel-serial hybrid marine power train system with LNG cooling, including a gas engine, an electric generator, a motor, a natural gas storage supplier. The gas engine is connected to the shaft belt motor through a gearbox, the motor is connected to the gearbox through a clutch, propellers are connected to the motor, and an engine cooling system and a fuel cell cooling system are connected to an LNG vaporization heat exchange apparatus; the electrical energy sources are the fuel cell, the electric generator and a storage battery. The arrangement of multiple power sources according to the present disclosure can meet ship requirements under various environments and circumstances, improve operating efficiencies of the gas engine, the shaft belt motor and the electric motor.

Abstract: The present invention provides an actually-measured marine environment data assimilation method based on sequence recursive filtering three-dimensional variation. The method includes: preprocessing actually-measured marine environment data; calculating a target function value; calculating a gradient value of a target function; calculating a minimum value of the target function; extracting space multi-scale information from the actually-measured data; and updating background field data to form a final data assimilation analysis field. The present invention improves the traditional recursive filtering three-dimensional variation method, and sequentially assimilates information with different scales, thereby effectively overcoming the problem that multi-scale information cannot be effectively extracted by a traditional three-dimensional variation method.

Abstract: A multiple optical channel autocorrelator based on an optical fiber circulator includes a broad-band light source, at least an optical-fiber sensor array, an adjustable multiple light beams generator, at least an optical fiber circulator and at least a photoelectric detector. The optical-fiber sensor array is composed of the sensing fibers connected end to end. The in line mirrors are formed by the connecting end faces of the adjacent fibers. The adjustable multiple light beams generator includes a fixed arm and an adjustable arm. The optical path difference between the fixed arm and the adjustable arm is adjustable in order to match the optical path of each sensor in the sensor array. The optical fiber circulator couples the signals generated by the multiple light beams generator to the sensor array, and couples the signals returned by the sensor array to the photoelectric detector. The photoelectric detector is connected to the optical fiber circulator.

Abstract: A multiple optical channel autocorrelator based on an optical fiber circulator includes a broad-band light source, at least an optical-fiber sensor array, an adjustable multiple light beams generator, at least an optical fiber circulator and at least a photoelectric detector. The optical-fiber sensor array is composed of the sensing fibers connected end to end. The online mirrors are formed by the connecting end faces of the adjacent fibers. The adjustable multiple light beams generator includes a fixed arm and an adjustable arm. The optical path difference between the fixed arm and the adjustable arm is adjustable in order to match the optical path of each sensor in the sensor array. The optical fiber circulator couples the signals generated by the multiple light beams generator to the sensor array, and couples the signals returned by the sensor array to the photoelectric detector. The photoelectric detector is connected to the optical fiber circulator.