Search

Copyright of Telecommunication Engineering is the property of Telecommunication Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Signal Processing is the property of Journal of Signal Processing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The evolution of performance parameter states of civil aviation engines presents multi-stage characteristics, and the current evaluation methods for performance parameters cannot effectively use the big data of state monitoring, or accurately identify their influence on the performance of civil aviation engines. Therefore, a new reliability evaluation model considering the phase correlation of dynamic evolution of civil aviation engine performance parameter states is proposed. The model uses dynamic Wiener process to characterize the states of the performance parameters of civil aviation engines according to the phase characteristics of the change point, and the joint probability distribution function model of the phased dynamic Wiener process is established by using Copula function. Monte Carlo simulation sampling method is used to evaluate the reliability based on the mathematical property of the first reach threshold of the evolution of performance parameter states. The actual condition monitoring data of airlines are used to verify the superiority of the proposed model, and the results show that compared with the model without considering the correlation between evolution stages, the average error of the proposed model for evaluating the state reliability of the performance parameters of civil aviation engines is reduced by about 12.9%. [ABSTRACT FROM AUTHOR]

To investigate the physiological response characteristics of cucumber to iso-osmotic NaCl and Ca(NO3)2 stress and the differential regulation mechanism of exogenous putrescine, so as to provide a theoretical basis for applying putrescine to alleviate soil salinization and conduct stress resistant cultivation of cucumber. In this study, the effects of foliar spraying exogenous sapropamine(8 mmol/L) on the growth and physiological characteristics of cucumber seedlings under iso-osmotic salt stress were studied using Jinchun 3 cucumber as test material, using 75 mmol/L of NaCl and 50 mmol/L of Ca(NO3)2 to simulate the conditions of iso-osmotic salt stress. The results showed that under iso-osmotic salt stress, exogenous putrescine induced plant antioxidant response by increasing leaf relative water content and chlorophyll content, mitigated membrane lipid peroxidation damage to protect membrane integrity, improved cell osmotic potential and regulated the synthesis of endogenous osmotic substances, thus enhancing cucumber seedling tolerance to iso-osmotic salt stress. Compared with simple salt stress, exogenous putroamine induced significant increase of POD activity in cucumber seedling leaves and roots under iso-osmotic salt stress. The activity of superoxide dismutase(SOD) in leaves increased significantly. Under NaCl stress, catalase(CAT) activity in leaves significantly increased, and CAT activity in roots significantly decreased. However, under Ca(NO3)2 stress, leaf CAT activity decreased significantly, and root CAT activity increased significantly. Meanwhile, exogenous putroamine induced significant increase of osmotic potential and the contents of free amino acids and soluble protein in seedling leaves and roots under NaCl stress, the content of proline in leaves significantly increased. Under Ca(NO3)2 stress, the contents of free amino acids and soluble protein in leaves significantly increased, and osmotic potential and the contents of soluble protein and soluble sugar in roots significantly increased. Exogenous putrescine could significantly alleviate iso-osmotic NaCl and Ca(NO3)2 stress, but there were differences for exogenous putrescine to alleviate the two salt stresses in antioxidation and osmotic regulation mechanisms in cucumber seedlings. [ABSTRACT FROM AUTHOR]