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Two ice and snow storm processes hit middle and eastern China during 31 January to 7 February (Process Ⅰ) and 19 February to 25 February (Process Ⅱ) in 2024, which are the most extreme ice and snow events since 2009. After the long-lasting cryogenic freezing rain and snow weather in the beginning of 2008, studies about freezing rain and snow storm have effectively improved the ability of subjective forecast and objective forecast skills of these kinds of weather. However, the accuracy of forecasting ice, freezing rain, and snow storm cannot meet demands of society. Recently, the capability of new types of observations has significantly advanced, and the surface observation system is more complete. Utilizing these more comprehensive observations to analyze and compare characteristics of these two processes will be beneficial for precious, objective and quantitative forecast of ice and snow storm, ice-accretion for example.The ice and snow surface observations, reanalysis dataset, and new types of observations, including dual polarization radar and raindrop spectrum, are used to analyze the precipitation, snowfall, ice-accretion and so on. In addition, microphysical characteristics, atmospheric circulations, and stratification features of these two processes are summarized and compared, and causes for differences is researched. Results show that the affected areas, duration, and total amount of precipitation in these two processes are similar. Process Ⅰ is characterized by deeper ice-accretion and snow depth, while Process Ⅱ is characterized by a larger affected area and increased snowfall. The observation of dual polarization radar shows that there are three layers of precipitation drops for Process Ⅰ: An ice crystal layer, melting layer, and liquid layer from top to the bottom. However, there are four layers for Process Ⅱ which are ice crystal layer, melting layer, liquid layer and refrozen layer from top to the bottom. So, for Process Ⅰ, there is no significant refreezing, and the precipitation droplets are mainly supercooled liquid falling through the cold layer near the surface. Process Ⅰ is mainly characterized by freezing rain and deeper ice accretion. During Process Ⅱ, significant refrozen to mixed or solid precipitation near the surface happens which results in more ice pellets which is not good to ice-accretion. On the other hand, the density of ice pellets is larger than that of snow, resulting in thinner snow depth and less ice-acceration for Process Ⅱ. The atmospheric circulation and stratification features indicate that both processes are characterized by cooperation of Siberia high and southern branch trough. However, the lower-level jet and Siberia high of Process Ⅱ are stronger than that of Process Ⅰ, leading to stronger warm layer and cold layer in Process Ⅱ and the colder low level cold layer is the main reason for the significant ice pellet in Process Ⅱ.

We aim to study the impact of microalgae fertilizer on soil nutrients, water conservation and crop yield and quality while also determining the optimal ratio of microalgae fertilizer to chemical fertilizer. Using “Xinoufen No.9” tomatoes as the test subject, we conducted pot experiments with four different treatments: control with 100% chemical fertilizer (CK), T1 (25% microalgae fertilizer + 75% regular chemical fertilizer), T2 (75% microalgae fertilizer + 25% regular chemical fertilizer) and T3 (100% microalgae fertilizer). The results show that an increased application of microalgae fertilizer enhanced the soil organic matter, ammonium nitrogen, available phosphorus and potassium content. T3 showed the most improvement followed by T2. The co-application of microalgae fertilizer with chemical fertilizer can significantly increase the stem girth, plant height and yield of tomatoes. At the same time, microalgae fertilizer effectively regulates leaf stomatal conductance, promoting tomato leaf respiration. As the stomatal conductance increases, the transpiration rate and net photosynthesis rate of all treatments improve, followed by a decline in intercellular CO2 concentration, with T2 exhibiting the best performance. Among all treatments, T2 treatment yielded the highest per-plant production (0.630 kg), followed by T3 (0.521 kg). This is because the microalgae fertilizer promotes the distribution of photosynthetic products to the fruit, enhancing the yield and quality of tomatoes. Additionally, the microalgae fertilizer also increases the content of soluble sugars, soluble protein, vitamin C and lycopene in the fruit while reducing the nitrate content. Compared to the control group CK, T2 increases the content of soluble sugars, vitamins and lycopene by 26.74%, 39.29% and 158.31%, respectively. Microalgae fertilizer also helps to improve soil water and thermal conditions, enhancing the water-use efficiency of tomatoes. Compared to CK, the water-use efficiency of T2 treatment increased by 54.05%. Correlation analysis indicates that water and fertilizer factors significantly affect tomato yield, with a correlation exceeding 70%. The net photosynthesis and transpiration rates significantly influence fruit quality, with correlations above 80%. By applying microalgae fertilizer, the efficiency of water and fertilizer use can be effectively improved, thus achieving the goal of water conservation and quality enhancement. Therefore, through comprehensive analysis, using the membership function method of indicators such as soil environment, crop yield, fruit quality and water-use efficiency, it is concluded that T2 is the optimal fertilization treatment. This study provides theoretical support for the application of microalgae biofertilizer technology in the cultivation of tomatoes and other vegetables in the northern, cold and arid regions.

In the present study, the Ni coatings on the surface of carbon fibers (CFs) were purposely regulated to provide the enhanced interfacial microstructure evolution and mechanical properties of CF reinforced Al–Mg matrix (CF/Al–Mg) composites. With increasing the pH value and deposition time, the coating thickness increased with the formation of island-like agglomeration as the pH value was 4.5. Based on the stable electroless plating process, different thicknesses of interconnected coatings were applied in the CF/Al–Mg composites fabricated by a semi-solid rolling process in open space. With the optimal thickness of 2.15 μm, the relative density of the composites increased from 89.7 % to 98.1 %, compared with that of the composites with the thickness of 0.54 μm due to eliminated un-infiltration defects. Simultaneously, optimized fiber dispersion and interfacial behavior were obtained, leading to effective load transfer, more energy absorption and consequently significant enhanced mechanical properties. The ultimate tensile strength (UTS) of the composites was 183 MPa with the largest improvement, which was 96.8 % higher than that of the matrix.