The identification method of blade material parameters and dynamic response analysis of impact

Caused by the foreign object damage (FOD), failure usually occurs within a very short time so there are many uncertainties about it and it is difficult for experimental instruments to monitor their dynamic response. Therefore, the dynamic response of the impact must be analysed by means of numerical simulation. But, there is a severe lack of the dynamic mechanical performance parameters of the structural materials involved. In this research, the first-class fan titanium alloy blade of a turbofan engine was used as a specimen to carry out the FOD test. The test results show that the crack damage has obvious morphological characteristics and narrow parameter range. Based on the results of the FOD test, the reverse identification of Johnson-Cook model parameters is used and the finite element model of the foreign object impacting blade is constructed. Finally, the dynamic response of the impact is analysed from the perspective of different strengths applied and contact forces, which further proves the scientific and engineering value of the model

Determinants and Impacts of the Relative Use of Depository Receipts and Euro Convertible Bonds by High-tech Corporations: An Empirical Study

This paper adopts Taiwan's high-tech companies as the sample to address and examine four new determinants of various foreign financing instruments and test their impacts on the issuing firms. Our empirical findings are consistent with the following notions. First, the firms with higher foreign holding and foreign investment will be likely to adopt foreign financing policy. Moreover, the firms with higher stock dividend payment in Taiwan will adopt both of ECB (Euro convertible bond) and DR (depository receipt). Firm managers with better education background will prefer DR. Second, the use of DR can effectively decrease the volatility of stock returns but also pronounce a negative influence on the mean of stock returns. In contrast, the use of ECB can effectively increase the mean but can not significantly decrease the volatility.

Variability of African easterly waves

African Easterly Waves (AEWs) are the most important rain modulators in the sub-Saharan Africa and precursors for tropical cyclone genesis in the Atlantic. While most previous studies have focused on the mean structure and dynamics of AEWs, evidence has shown that AEWs can vary substantially in terms of their structure and characteristics. Therefore, the overarching goal of this dissertation is to document the variability of AEWs and understand its causes. The goal is accomplished through two different but complementary approaches: (1) statistical analysis and (2) vorticity tracking

The processing peptidase of yeast mitochondria

Two proteins co-operate in the proteolytic cleavage of mitochondrial precursor proteins: the mitochondrial processing peptidase (MPP) and the processing enhancing protein (PEP). In order to understand the structure and function of this novel peptidase, we have isolated mutants of Saccharomyces cerevisiae which were temperature sensitive in the processing of mitochondrial precursor proteins. Here we report on the mif2 mutation which is deficient in MPP. Mitochondria from the mif2 mutant were able to import precursor proteins, but not to cleave the presequences. The MPP gene was isolated. MPP is a hydrophilic protein consisting of 482 amino acids. Notably, MPP exhibits remarkable sequence similarity to PEP. We speculate that PEP and MPP have a common origin and have evolved into two components with different but mutually complementing functions in processing of precursor proteins