During the design and manufacture of hydraulic system, valve block of processing is time-consuming and labor-intensive, and its easy to make a mistake. In this paper, a simple numerical control system based on PLC control to solve the practical engineering problem is studied. An automatic positioning based on parameters of holes which are drawn by AutoCAD and an automatic machining of holes can be realized by the control system. Its also discussed that the method and process of the design of software and hardware.
An efficient process has been developed for the synthesis of N,N′-Diphenylpiperazine and its formyl derivative. N,N′-Diphenylpiperazine was prepared from aniline with tris(2-chloro ethyl)phosphate as an excellent alkylating reagent at a high yield (90.86%), which gave N,N′- bis(p-formylphenyl) piperazine by Vilsmeier-Haack reaction in a good yield of 86.70%. Particularly, the purity of products and the reaction progress were monitored by simple and reliable thin-layer chromatography (TLC) methods on glass-backed GF254 silica gel plate. The structure of all the products was confirmed by their melting points, spectral data (IR, 1H-NMR).
Abstract. Electro-hydraulic proportional closed control system is designed which fully integrated electrical and hydraulic advantages of both. The dynamic mathematic model of the hydraulic system is built and the dynamic characteristics of the system are analyzed accurately. The advanced PID controller is adopted to correct the system, and have improved the dynamic quality of the system. In this paper, the hydraulic system is simulated on the basis of the Simulink and DSHplus professional hydraulic simulation software and the results of simulation prove that the qualities of the system can satisfy with the requirement much better.
Abstract. Based on Newton method, the nonlinear differential equation of FSI vibration of hydraulic pipe on aero-engine has been established. The equation include visco-elastic coefficient, and the dimensionless equation was got. The influence of mass ratio, velocity of fluid and axial force on natural frequency of the pipe was researched by analyzing the FSI vibration equation of the pipe. The influence of fluid pressure on natural frequency was verified by experiment. And vibration response of the pipe was obtained by experiment at different driving frequency. The conclusion of the experiment was consistent with the result of the theory.
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