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There is a problem about microstructure evolution and properties degradation for the superalloy turbine blades in long term service conditions. DZ406 alloy samples were pre-loaded to simulate the high temperature service environment of turbine blades. The thermodynamic coupling simulation conditions were 980 ℃/70 MPa, 980 ℃/110 MPa, 980 ℃/140 MPa and 980 ℃/180 MPa respectively. And then the samples were subjected to stress rupture property test at 980 ℃/275 MPa. The microstructure and 980 ℃/275 MPa rupture life of the samples under different service loading conditions were observed and analyzed. The results show that the heat treatment microstructure of DZ406 alloy is composed of carbides, residual γ +γ´ eutectic and regular γ´ phase. The morphology and size of carbides and eutectic have no obvious change with the increase of loading stress under simulated service conditions. The γ´ phase of the sample parallel to [001] direction presents different degrees of rafting, and the size of γ´ phase perpendicular to [001] direction obviously increases. The residual stress rupture life of the sample declines rapidly with the increase of service stress.

To solve the poor precision and low efficiency of manual grinding de-weight dynamic balance of turbopump rotor, the laser de-weight dynamic balance technology of rotating machines is adopted. Combined with the advantages of laser de-weight, such as, fast processing speed high machining precision and good machined surface quality, the smooth transition of the machined surface was realized by means of hierarchical machining. According to the characteristics of the turbopump rotor structure, the equivalent transformation model for laser de-weight turbopump rotor was built to convert the unbalance into laser processing parameters, which achieve the rapid and accurate de-weight of turbopump rotor. It focuses on solving the repeatedly loading and low accuracy of manual grinding dynamic balance. To verify the effectiveness of the proposed technique, laser de-weight experiments were carried out on two turbopump rotor test pieces. A dynamic balance test bench was set up to measure the rotor residual unbalance at 1800 r/min test speed, which is low dynamic balance. The results show that the machined surface transition was smooth, the residual unbalance was small and the machining efficiency was high. The effect of laser de-weight dynamic balance reached the expectation. It is an universal technology which is not limited to the dynamic balance of turbopump rotor, but also applicable to other rotating machinery.. [ABSTRACT FROM AUTHOR]

Background: We aimed to examine the evolution of blood lipids and compare the risk of dyslipidemia between antiretroviral-naive people living with HIV who received tenofovir disoproxil fumarate (TDF), lamivudine (3TC), and efavirenz (EFV) (TDF + 3TC + EFV) and those who received coformulated elvitegravir, cobicistat, emtricitabine, and tenofovir alafenamide (E/C/F/TAF)., Methods: We retrospectively reviewed the medical records of 2343 antiretroviral-naive people living with HIV who initiated TDF + 3TC + EFV or E/C/F/TAF. A propensity score matching method was used to compare longitudinal changes of blood lipids between the 2 groups., Results: By using 1:3 matching ratio, we included 253 and 91 matched patients in TDF + 3TC + EFV group and E/C/F/TAF group, respectively. The levels of total cholesterol, triglyceride, low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol were higher in E/C/F/TAF group than those in TDF + 3TC + EFV group at 3, 6, 9, and 12 months (Wilcoxon test, all Ps < 0.05), except for high-density lipoprotein cholesterol at 9 and 12 months. The cumulative rates of hypercholesterolemia, hypertriglyceridemia, and high LDL-C in PLWH with normal lipid levels in E/C/F/TAF group were higher than those in TDF + 3TC + EFV group (hypercholesterolemia, 59.7% vs 21.5%, P < 0.001; hypertriglyceridemia, 69.5% vs 46.3%, P < 00.001; and high LDL-C, 41.5% vs 14.2%, P < 0.001). Multivariate analysis showed treatment with E/C/F/TAF was associated with a significantly higher risk of hypercholesterolemia [adjusted hazard ratio (HR), 4.12; 95% confidence interval (CI): 2.65 to 6.41], hypertriglyceridemia (adjusted HR, 1.69; 95% CI: 1.18 to 2.43), and high LDL-C (adjusted HR, 4.60; 95% CI: 2.66 to 7.97)., Conclusions: We concluded that treatment with E/C/F/TAF resulted in higher risks of dyslipidemia compared with TDF + 3TC + EFV., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)