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Background: Low-frequency resonance is one of the common issues encountered during the variable-frequency operation of condensate water pumps. There have been numerous patents and papers proposing solutions to address the low-frequency resonance problem in condensate water pumps. However, the solutions for resonance problems often need to be tailored to specific circumstances.Methods: Based on the acoustic method, the dynamic model of the rotor and inner cylinder of Jiangsu Guohua Chenjiagang Power Plant 2B condensate pump is established to compare the difference between dry modal and fluid-structure coupling modal, the influence of perpendicularity, concentricity and bearing wear on the natural frequency of rotor is studied.Results: The rotor is rigid under normal conditions. When the bearing is worn, the frequency of the rotor will be greatly reduced and may fall into the frequency conversion operation range to excite resonance. The deviation of perpendicularity and concentricity will not directly lead to the decrease of rotor modal but will lead to the increase of bearing stress, aggravate bearing wear, and then affect the rotor modal. As the inner cylinder only relies on the fixed support at the top, the structure stiffness is low, which may lead to low-frequency resonance. By adding two support structures at the guide vane, the first-order modal frequency of the inner cylinder can be increased from 3.29 Hz to 28.88 Hz, effectively avoiding the operating frequency range of the system.Conclusion: This study can guide the optimization of similar pump structures.

Bread wheat (Triticum aestivumL.) is the most widely grown crop in the world. Rhizoctonia cerealis, the causal agent of wheat sharp eyespot disease, has 21 become epidemic in many countries. In the present study, we performed transcriptome analysis in wheat infected by R. cerealisat 0, 12, 30, 70, and 98 h post-infection using R. cerealis-resistant and -susceptible genotypes (CI12633 and ‘Yangmai15’, respectively). We used quantitative real-time PCR to validate the Illumina gene expression data, and identified new gene annotations for 23,654 unigenes in the RNA samples from the resistant and susceptible cultivars. Comparing the same inoculation times, we found that the number of DEGs (differentially-expressed genes) increased gradually before 70 h and declined at 98 h in the two RNA samples. Furthermore, the expression of resistance-associated genes occurred earlier in CI12633 than in ‘Yangmai15’, and higher mRNA expression levels were detected in CI12633; this suggests that timing and relative expression levels of these genes are important in the CI12633-R. cerealisinteraction. Functional annotations associated with sharp eyespot resistance included genes involved in energy production and conversion, posttranslational modification, protein turnover, chaperones, secondary metabolite biosynthesis, transport and catabolism, and defense mechanisms. The results of pathway enrichment analysis showed that the DEGs participate in glutathione metabolism, glycerophospholipid metabolism, lysine degradation, plant-pathogen interaction, glyoxylate and dicarboxylate metabolism, and other resistance-associated metabolic pathways. Disease inoculation experiments and the validation of in vitro antifungal activity of the candidate genes showed that the genes were up- or down-regulated in the resistant genotype CI12633 30 h after inoculation compared to its control, which validated the results of the RNA-seq analysis. The results of our study will help to understand the molecular basis of the host response to R. cerealisinfection in wheat, and will also enable the future genetic improvement of sharp eyespot resistance in wheat through the incorporation of novel resistance genes.