Pipeline magnetic flux leakage (MFL) internal detection technology is the most widely used and effective method in the field of long-distance oil and gas pipeline online detection. With the improvement of data quantization precision, the influence of stress on MFL signal has been paid more and more attention. In this paper, the relationship between stress and saturation magnetization is introduced based on J-A theory. The analytical model of MFL detection signal for pipeline composite defects is established. The MFL signal characteristics of composite defects are quantitatively calculated. The effect of stress on MFL signal is studied. The theoretical analysis is verified by experimental data and excavation results. The researches show that the saturation magnetization of ferromagnets decreases exponentially with the increase of stress in strong magnetic field. The MFL signal of composite defect is weaker than that of volumetric defects of the same dimension. The axial amplitude and radial peak-to-peak value of MFL signal decrease with the increase of stress around the defect. The axial amplitude and radial peak-to-peak value of MFL signal increase non-linearly with the increase of width and depth of defects. When using MFL signal to judge the defect depth, it is necessary to make clear whether there is stress concentration phenomenon around the defect because the stress will lead to underestimation of the defect depth.

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Teaching quality affects the level of teaching and educational standards in the school. Conducting objective, impartial and scientific evaluation for curriculum teaching quality is an important task of teaching reform. According to the construction of teaching quality evaluation model based on AHP, this paper uses evaluation methods of students teaching evaluation, peer teaching evaluation, supervision teaching evaluation, using AHP to make relevant quantitative indicators of teaching quality and comprehensively evaluate teaching quality so as to objectively and effectively reflect the actual teaching effectiveness, so that it will provide decision-making reference for "excellent lesson excellent pay" course selection. The results show that the Teaching Quality Evaluation System Based on AHP Applies to "excellent lesson excellent pay" course selection, which is an effective evaluation method.