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The present day’s thermal lithospheric thickness is usually calculated by one or two-dimensional steady-state heat conduction equation. Using the latest measured heat flow data of the North China Craton(NCC) and the one-dimensional steady-state heat conduction equation, the calculated thermal lithospheric thickness of the NCC is between 34.8-190 km. There are some regions, whose lithosphere is very thin, and the lithosphere adjacent to them is very thick, so the bottom boundary of the lithosphere fluctuates greatly. The last thinning of the NCC stopped at~24 Ma and then entered the thermal subsidence period. To study whether the fluctuates of the bottom boundary of the lithosphere can be maintained during the long-term thermal subsidence process, a thermal subsidence model was established. The modeling results show that after the thermal subsidence of 24 Ma, the fluctuates of the bottom boundary of the lithosphere are difficult to maintain, and the present day’s thermal lithospheric thickness of the NCC should not exceed 73 km, and the maximum surface heat flow value of the NCC is 75.6 mW·m-2 due to the deep thermal state. The high heat flows anomaly in the NCC is more caused by shallow activities and cannot reflect the deep thermal state. After correction, the current thermal lithospheric thickness of the North China craton is ~73-190 km, and the bottom boundary of the lithosphere changes gently., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

The Sichuan Basin is an important hydrocarbon-bearing basin in China, and its southwestern part is located in the outer zone of the Emeishan Large Igneous Province. The thermal influence of Emeishan basalt on hydrocarbon development in the Sichuan Basin has been of great interest. Recent paleo-heat flow recovery calculations have yielded the presence of high paleo-heat flows greater than 100 mW/m2 duirng the Permian at some points in the basin, which are thought to be related to Emeishan basalt. In order to understand the causes of these high paleo-heat flows and the thermal effects of basaltic magma overflowing to the surface on the lower strata, the thermal effects of Emeishan basalt were simulated by 2D finite element method. The following conclusions are drawn: (1) The changes in surface heat flow generated by the intrusion of Emeishan basaltic magma into the bottom of the lithosphere and the bottom of the crust are both inconsistent with the high paleo-heat flow of >100 mW/m2 during the Permian of the Sichuan Basin, and magma intruded into the interior of the crust can cause such high paleo-heat flows.(2) The thermal disturbance caused by different thicknesses of magma at the surface to the lower strata at different depths was calculated. The thicker the magma at the surface and the shallower the overlying strata, the greater the thermal disturbance of the magma to the strata, while the adjacent strata are unaffected. The thermal influence on the hydrocarbon source rocks can thus be inferred., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

Fermented dairy products have been recognized as the best carriers for the administration of probiotics. Because one of the potential probiotic strains, Lactobacillus plantarum, has poor proteolytic ability and weak acidifying capacity in milk fermentation, the aim of this study was to preliminarily investigate the stimulation effect of plant-based meals on L. plantarum CCFM8661 growth in milk, and subsequently develop a yogurt or yogurt drinks containing probiotic strain L. plantarum CCFM8661. Milk supplemented with different concentrations (5 to 10%, wt/wt) of oat extract and malt extract, inoculated with 2.5 × 107 cfu/mL of L. plantarum CCFM8661, and then incubated at 35°C. The pH value, titration acidity, and viable cell counts during 48-h fermentation at 35°C and 25-d storage at 4°C, were determined at different intervals. The results showed that the promotion effects of oat extract and malt extract on L. plantarum CCFM8661 growth rate in milk were much stronger than almond, walnut, sweet corn, peanut, and soybean meals. In addition, the stimulation effect of oat extract was associated with its concentration, and was much stronger than that of malt extract. Furthermore, viable counts and titration acidity of yogurt were gradually increased in the oat extract group, whereas viable counts were gradually decreased and titration acidity were slightly increased in the malt extract group during the 25-d storage at 4°C.

The screw rod is widely used in the oil drilling, chemical industry, light industry and so on. Its machining accuracy affects directly the quality and efficiency of instruments. Thus a deep research on the machining process of the screw rod is urgently needed. The fitting method of the spiral surface cross-section is one of the key issues. It was proposed that cubic spline and parametric cubic spline interpolation function were taken to approximate the spiral surface cross-section by comparing different methods of curve fitting. Coefficients of them were derived, fitting equations were presented and examples were taken to verify the fitting results .At the same time, key issues on the skewness, tangent vectors of ends and so on were involved both in the process of cubic spline and in parametric cubic spline fittings. Corresponding fitting function can be chosen on the basis of foregone data points, so as to provide smooth curves to generate accurate tool path. (4 pages)