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Biogenic amines (BAs) and microbial diversity are important factors affecting food quality and safety in fermented foods. In this study, the bacterial and fungal diversity in grasshopper sub shrimp paste taken at different fermentation times were comprehensively analyzed, while the pH, colony counts, salinity, total volatile base nitrogen (TVB-N) and BA contents were quantitatively determined. In addition, the correlations among the samples with respect to microbial communities and the different parameters investigated especially BAs were also established. By combining the results of spearman correlation heatmap with the contents of BAs produced by the 102 halotolerant bacteria isolated from the grasshopper sub shrimp paste, six major genera of bacteria (Jeotgalibaca, Jeotgalicoccus, Lysinibacillus, Sporosarcina, Staphylococcus, and Psychrobacter) were found to be positively correlated with BA production level, suggesting that these bacteria might have a strong tendency to produce BAs. Other bacteria such as Lentibacillus, Pseudomonas, and Salinicoccus were considered as poor BA producers. The grasshopper sub shrimp paste was characterized by a relatively high abundance of Tetragenococcus, which was the dominant genus during the fermentation process, and it also produced a relatively high level of BAs but the spearman correlation heatmap revealed a negative correlation between T. muriaticus and BA level. Analysis of the species relevance network in grasshopper sub shrimp explained that the actual production of BAs by a certain strain was closely related to other species present in the complex fermentation system.

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Based on the traditional sintering model incorporating the characteristic of microwave sintering, the ionic conductance diffusion mechanism in microwave sintering was studied. A flat-ball model was presented to describe the kinetics process in microwave sintering, and was applied to the sintering process of TZP and ZrO 2 -Al 2 O 3 ceramics. The results indicate that the shrinkage rate of materials in microwave sintering is proportional to t 2/3 and r −4/3 , respectively, where t is the sintering time and r is the particle radius. Whereas, the shrinkage rate of materials in conventional sintering is proportional to sintering time t 2/5 . Our model suggests that microwave sintering is faster than conventional sintering, which shows a good agreement with the experimental observation in sintering process of TZP and ZrO 2 -Al 2 O 3 . microwave sintering, ionic conductance, kinetics, sintering mechanism Microwave sintering is a new sintering technology developed in the middle to late period of the 1980's, which is characterized by fast densification for ceramic materials [1] . It makes use of dielectric loss of materials in microwave electromagnetic fields to heat ceramic matrix to the sintering temperature fast. Recently, microwave sintering technology has received intensive interests in fabrication of various materials. For example, SiO 2 , B 4 C, Al 2 O 3 , TiO 2 , ZrO 2 , ZnO, etc., have been prepared by microwave sintering technology successfully [2] .Compared with traditional electric heating, the microwave heating effect mainly comes from the continuous changes of material polarization in alternating electromagnetic field. The continuous changes of dipoles in materials can produce strong vibration and friction, therefore, generating heat to achieve sintering [3] . Recent researches indicate that the alternating microwave electromagnetic field has a series of non-thermal effects to enhance the sintering, including improving densification, gearing up grain growth, quickening chemical reaction, etc. [4] . Janney et al. [5] used 18 O isotopic tracing method to investigate diffusion process in Al 2 O 3 single crystal.The results showed that the diffusion coefficient in microwave sintering process is higher than that in conventional sintering process, suggesting that microwave electromagnetic field promotes atomic diffusion. Freeman et al.'s work [6] indicated that microwave fields have enhanced the effect on the ionic conductance. Freeman et al. [7] found that high frequency electric fields promote transfer of charged vacancy on grain surfaces, hence cause easily plastic deformation of grains, thus enhancing the sintering. Huang et al. [8] investigated the directional move of the charged defects in the microwave electric field, and observed that the shrinkage rate parallel to the direction of the electric field was bigger than that perpendicular to the direction of the electric field. They thus believed that microwave field just improved densification of the parallel direction of electric field. Aimin and Jiawen [9] ...