Mathematics education is a comprehensive scientific system that holds significant importance in studying the seamless integration between university mathematics education and secondary mathematics education. This research paper delves into the challenges encountered during the transition from high school to university mathematics and offers analytical strategies and recommendations for both teachers and students. The objective is to enhance the continuity and coherence of mathematics education. Furthermore, tailored recommendations are provided to bridge the gap between high school and university mathematics education, taking into consideration the unique characteristics of students from different provinces and cities.

Using the rank scale rule, taking 47 major port cities in China from 2001 to 2015 as research samples, this paper discusses the rank scale characteristics and hierarchical structure of coastal port city system from a multi-functional perspective, and divides the coupling type of multi-functional development based on shipping logistics. The research shows that: 1) from 2001 to 2015, the scale-free area of manufacturing function order scale distribution in the coastal port city system appeared bifractal structure, the hierarchical segmentation characteristics appeared, and the other functions were single fractal; From the perspective of long-term evolution, only the order and scale distribution of shipping logistics function has developed from centralization to equilibrium, while the business function, manufacturing function (scale-free region I), modern service function and population distribution function are in a centralized situation. 2) The hierarchical structure of coastal port city system has gradually changed from pyramid structure to spindle structure, and generally formed five levels: national hub, regional hub, regional sub center, regional node and local node. 3) From the perspective of multi-functional coupling types, the traditional functions of port cities are generally ahead, while the high-end service functions lag behind, and the improvement speed of urban functions is slow and tends to be flat, indicating that the multi-functional development of China’s coastal port cities is still at a low level, and the industrial system structure needs to be further optimized. 4) From the perspective of port cities at different levels, the functions of regional hub cities and regional sub central cities are in the stage of rapid growth; regional and local node cities are still in the growth stage of traditional functions such as industry and commerce.

The nylon 66/nano-CaCO3 composites were prepared by melt blending on a twin-screw extruder. Scanning electron microscopy (SEM), polarized light microscopy (PLM), thermal loss (TGA) and differential scanning calorimetry (DSC) The effects of nanometer calcium carbonate on the polycrystalline behavior and thermal properties of nylon 66/nano CaCO3 composites were investigated. The results show that the nanometer calcium carbonate particles are dispersed in the nylon 66 matrix and exist in the form of aggregates. The nanometer calcium carbonate has the effect of heterogeneous nucleation, which can reduce the size of the spherules. The decomposition temperature of the nylon 66 is 400 ℃, the addition of nano-CaCO3 to reduce the decomposition temperature. At the same time, DSC test showed that the β-crystalline form in the material reduced the melting temperature of the material. The addition of nano-CaCO3 in the nylon 66 matrix resulted in the decrease of the crystallization temperature and the increase of the half-height width of the endothermic peak. The lower the crystallization temperature, the wider the crystallization temperature range.

With fresh bitter melon and green tea as main ingredients, xylitol, sucrose and citric acid as auxiliary ingredients, a new cool health tea beverage was developed. The optimum formula of low sugar bitter melon green tea compound beverage was developed by single factor experiment and orthogonal test based on sensory evaluation. The results showed that the optimum formula was as follows: Bitter melon juice was added at 7%, green tea extract was added at 20%, total xylitol and sucrose was 6% (mass ratio 1:1), citric acid was added at 0.2%, and the volume was fixed to 100% with deionized water. The product has light green color, harmonious aroma, moderate acidity and sweetness, and clear texture. The aftertaste is long, with tea polyphenol content of 342 mg/kg, soluble solids of 5.2% and pH 5.8.