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The crack-like defects of oil and gas pipelines, especially the crack-like defects on the inner surface, are the main factors leading to pipeline failure. However, due to the limitation of the existing inline inspection technology, the cracklike defects are difficult to detect through inline inspection. Herein, various eddy current inline inspection tests of crack-like defects were performed by setting up an eddy current high-speed automatic testing device to detect the crack-like defects in the pipe body and girth weld at different defect depths based on the electromagnetic eddy current technology. In addition, the eddy current signal characteristics of crack-like defects were analyzed, and the feasibility of applying electromagnetic eddy current technology to the inline inspection of crack-like defects was verified. The test results show that the crack-like defects of oil and gas pipelines at different locations can be distinguished by the impedance signal of defects at a higher inspection speed. Meanwhile, the signal characteristics become more obvious with the increase of defect depth, but attenuate with the increasing of the liftoff value of defects. In addition, the greater signal-to-noise ratio of defect signal can satisfy the requirements for accurately identifying the crack-like defects.

[Objective] Ecological land fragmentation has a serious impact on the structural integrity and function of the ecosystem. The conflict between construction land expansion and ecological land fragmentation is one of the problems that need to be solved in the process of implementing the development and protection strategy for harmonious coexistence between humans and nature. [Methods] In this study, based on the analysis of temporal and spatial changes in ecological land, a comprehensive indicator system of fragmentation degree was established for the southern Jiangsu Province region to explore the temporal and spatial characteristics of ecological land fragmentation degree. Based on the theory of the environmental Kuznets curve (EKC), the response of ecological land fragmentation degree to construction land expansion was investigated. [Results] (1) From 2000 to 2020, the ecological land in southern Jiangsu Province was mainly converted into construction land, followed by cultivated land. A certain amount of cultivated land and a small amount of construction land were converted into ecological land; (2) The degree of ecological land fragmentation increased first and then decreased. Along the Yangtze River and in the surrounding areas of key water bodies such as the Taihu Lake, the Gucheng Lake, and the Gehu Lake, there was a remarkable increase in the degree of fragmentation; (3) There is an inverted U-shaped relationship between the scale of construction land and the fragmentation of ecological land. With the increase of the area of construction land, the degree of fragmentation of ecological land increases first and then decreases. [Conclusion] The spatiotemporal response of ecological land fragmentation to construction land expansion is consistent with the EKC theory, and most urban centers in southern Jiangsu Province have reached the inflection point by 2020. By exploring the balance between ecological land occupation and compensation, conducting ecological planning in advance, building ecological barriers, timely assessing the impact of construction land expansion on ecological land, and formulating response measures, the layout coordination of construction land and ecological land will be improved, and the coordinated progress of “smart growth” and green development can be realized.