In our experiment, a dynamic method was taken to measure the solubilities of the 2,4-dimethoxybenzoic acid under atmospheric pressure (p = 0.1 MPa) in ethanol, npropanol, isopropanol, n-butanol, isobutanol, and ethyl acetate as well as in the isopropanol + ethyl acetate mixtures from (288.15 to 323.15) K. The experiment results have proved that the rising temperature leads to increased solubility of the 2,4-dimethoxybenzoic acid in all selected solvents. The changing model parameters in each selected solvent was recorded and calculated, respectively, during the experiments and the solid− liquid equilibrium data in pure and mixed solvents was correlated with a series equations, including the modified Apelblat equation, Wilson equation, UNIQUAC equation, and the Jouyban−Acree. During the study, the computational values were in good agreement with the experimental results according to the calculations based on all selected equations, however the modified Apelblat equation stood out to be the most suitable with the most accuracy. In addition, some thermodynamic parameters of the solution of 2,4-dimethoxybenzoic acid including dissolution enthalpy (ΔH sol ), entropy (ΔS sol ) and the Gibbs energy (ΔG sol ) were obtained via the van't Hoff analysis. The positive values ofΔH sol andΔG sol indicated that the dissolution process of dissolving 2,4-dimethoxybenzoic acid is endothermic.

A finite element method for simulation of lens-less line focus acoustic microscopy is proposed in this paper to nondestructively evaluate the leaky surface wave (LSW) velocity. The defocusing measurement model is established, in which the geometrical focusing radius will be 20 mm. The piezoelectric polyvinylidene fluoride film is selected as the active element. The excitation is a standard black Harris wavelet signal with a centre frequency of 5 MHz. Simulations of measurements on typical bulk materials (Al) are carried out. Then, the time-resolved wave signal series are acquired when the defocusing distance varies continuously. The LSW velocity will be easily determined by the examination of the slope of the LSW's arrival time versus the defocusing position. The LSWs' propagating path will be analyzed geometrically in time-domain. Meanwhile, the LSWs' velocities are also extracted by applying the specially developed digital signal processing algorithm to the defocusing experimental data, which is called V (f, z) analysis method based on two-dimensional fast Fourier transform. Finally, the relationship between the time-resolved method and the V (f, z) technique is discussed, in which the interpretation of the formation of surface waves and the description of its analysing methods will be given.

Aiming at the requirement of pipelines' seismic design, the code of "Seismic Technical Code for Oil and Gas Transmission Pipeline Engineering" was published, and the code presented the seismic design method of pipelines subjected to active fault, and pointed out that finite element method is necessary when pipeline is axial compressed. Based on the strain calculation method proposed by the code, this paper discuss the influence factors such as pipeline-fault angle and pipeline buried depth, then presents pipeline strain variation trend when subjected to active fault movement. Meanwhile, this paper adopts finite element method to analyze pipeline strain distribution, and points out that pipeline strain is composed of axial tension/compress strain and bend strain, which could explain the pipeline strain distribution, and the elliptic phenomenon of pipeline should be considered in the future research works and code revision. This paper provides the technical reference for pipeline seismic design.

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To discuss the dynamic characteristics of the height of high-speed corrugated roller mechanism, the mathematical model of the corresponding upper and lower corrugator roll is established , introduce the corresponding convex curve equation. By theoretical calculation,we got 6 groups of upper and lower height of the corrugated roller. Use ANSYS to simulate the working state of the corrugated rolle and establish finite element model to analyze force on the corrugated roller load, geometric constraints, thereby gaining the simulation status under 6 groups of height in the upper and lower corrugated roller. Compensate the results of theoretical calculation of the simulation conditions of convex curve and improve the contact performance of the corrugated roller .