Nonlinear dynamic analysis of high-speed gear pair with wear fault and tooth contact temperature for a wind turbine gearbox

This paper aims to reveal the relationship between the high-speed gear wear and nonlinear dynamics for a wind turbine gearbox considering the tooth contact temperature. The temperature and deformation of the tooth surface are calculated respectively using the Blok's flash temperature theory and thermal deformation formula, and the meshing stiffness caused by the tooth contact temperature is obtained using the Hertz theory. The wear depth and time-varying meshing stiffness of high-speed gears are calculated using the Archard's equation and potential energy method, respectively. The nonlinear dynamic model of the gearbox is established to study the characteristics, and the frequency domain values of gear wear are compared with experimental data. The results show that the tooth contact temperature makes the time-varying meshing stiffness decrease, then affecting the dynamics of the system, the stability decreases with the increase of comprehensive transmission error, and for the gearbox considering the contact temperature, the gear wear makes the chaotic motion occur in advance and its region increase obviously. The research provides a basis for the wear fault diagnosis and detection of gear transmission systems. </p

Nonlinear dynamic analysis of high-speed gear pair with wear fault and tooth contact temperature for a wind turbine gearbox

This paper aims to reveal the relationship between the high-speed gear wear and nonlinear dynamics for a wind turbine gearbox considering the tooth contact temperature. The temperature and deformation of the tooth surface are calculated respectively using the Blok's flash temperature theory and thermal deformation formula, and the meshing stiffness caused by the tooth contact temperature is obtained using the Hertz theory. The wear depth and time-varying meshing stiffness of high-speed gears are calculated using the Archard's equation and potential energy method, respectively. The nonlinear dynamic model of the gearbox is established to study the characteristics, and the frequency domain values of gear wear are compared with experimental data. The results show that the tooth contact temperature makes the time-varying meshing stiffness decrease, then affecting the dynamics of the system, the stability decreases with the increase of comprehensive transmission error, and for the gearbox considering the contact temperature, the gear wear makes the chaotic motion occur in advance and its region increase obviously. The research provides a basis for the wear fault diagnosis and detection of gear transmission systems. </p

DataSheet_1_Effects of anti-inflammatory therapies on glycemic control in type 2 diabetes mellitus.docx

BackgroundThe overall evidence base of anti-inflammatory therapies in patients with type 2 diabetes mellitus (T2DM) has not been systematically evaluated. The purpose of this study was to assess the effects of anti-inflammatory therapies on glycemic control in patients with T2DM.MethodsPubMed, Embase, Web of Science, and Cochrane Library were searched up to 21 September 2022 for randomized controlled trials (RCTs) with anti-inflammatory therapies targeting the proinflammatory cytokines, cytokine receptors, and inflammation-associated nuclear transcription factors in the pathogenic processes of diabetes, such as interleukin-1β (IL-1β), interleukin-1β receptor (IL-1βR), tumor necrosis factor-α (TNF-α), and nuclear factor-κB (NF-κB). We synthesized data using mean difference (MD) and 95% confidence interval (CI). Heterogeneity between studies was assessed by I2 tests. Sensitivity and subgroup analyses were also conducted.ResultsWe included 16 RCTs comprising 3729 subjects in the meta-analyses. Anti-inflammatory therapies can significantly reduce the level of fasting plasma glucose (FPG) (MD = - 10.04; 95% CI: -17.69, - 2.40; P = 0.01), glycated haemoglobin (HbA1c) (MD = - 0.37; 95% CI: - 0.51, - 0.23; P ConclusionOur meta-analyses indicate that anti-inflammatory therapies targeting the pathogenic processes of diabetes can significantly reduce the level of FPG, HbA1c, and CRP in patients with T2DM.</p

Two 3-D coordination polymers based on 5-sulfoisophthalic acid sodium salt: synthesis, crystal structures and photocatalytic reduction of CO₂

Two new coordination polymers constructed from 5-sulfoisophthalic acid sodium salt (NaH2SIPA) and Co or Cu cations, [Co3(SIPA)2(4,4′-bpy)4(H2O)6]·4H2O (1) and [Cu6O3(HSIPA)3(4,4′-bpy)6(H2O)3]·7H2O (2), have been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction (SXRD), powder X-ray diffraction (PXRD), IR spectroscopy, thermogravimetric analysis, UV-Vis spectroscopy, and elemental analysis. Compound 1 represents a twofold-interpenetrating 3-D framework based on Co, SIPA, and 4,4′-bipyridine ligands with a qzd topology. Different from 1, compound 2 shows a 3-D self-penetrating framework based on Cu, HSIPA, and 4,4′-bipyridine ligands. Furthermore, the photocatalytic performance in reduction of CO2 of 1 under visible light was investigated.</p

Datasheet1_Predictive value of the inconsistency between the residual and post-PCI QFR for prognosis in PCI patients.docx

IntroductionTo investigate the prognostic value of the consistency between the residual quantitative flow ratio (QFR) and postpercutaneous coronary intervention (PCI) QFR in patients undergoing revascularization.MethodsThis was a single-center, retrospective, observational study. All enrolled patients were divided into five groups according to the ΔQFR (defined as the value of the post-PCI QFR minus the residual QFR): (1) Overanticipated group; (2) Slightly overanticipated group; (3) Consistent group; (4) Slightly underanticipated group; and (5) Underanticipated group. The primary outcome was the 5-year target vessel failure (TVF).ResultsA total of 1373 patients were included in the final analysis. The pre-PCI QFR and post-PCI QFR were significantly different among the five groups. TVF within 5 years occurred in 189 patients in all the groups. The incidence of TVF was significantly greater in the underanticipated group than in the consistent group (P = 0.008), whereas no significant differences were found when comparing the underanticipated group with the other three groups. Restricted cubic spline regression analysis showed that the risk of TVF was nonlinearly related to the ΔQFR. A multivariate Cox regression model revealed that a ΔQFR≤ −0.1 was an independent risk factor for TVF.ConclusionsThe consistency between the residual QFR and post-PCI QFR may be associated with the long-term prognosis of patients. Patients whose post-PCI QFR is significantly lower than the residual QFR may be at greater risk of TVF. An aggressive PCI strategy for lesions is anticipated to have less functional benefit and may not result in a better clinical outcome.</p

Nonfused Ring Electron Acceptors for Efficient Organic Solar Cells Enabled by Multiple Intramolecular Conformational Locks

Nonfused ring electron acceptors (NFREAs) have become a research hotspot of organic solar cells (OSCs) due to their facile synthesis. However, efficient NFREAs not only need to maintain the advantages of FREAs but also need to optimize the molecular structure of the conjugate backbone to achieve good planarity. Therefore, choosing the appropriate building blocks is a prerequisite for achieving efficient OSCs. Here, two simple NFREAs 2T2CSi-4F and 4T2CSi-4F, based on diester-thieno­[3,2-b]­thiophene (2T2C) as the central core unit and 4,4-di-2-ethylhexyl-dithieno­[3,2-b:2′,3′-d]­silole (DTSi) or thieno­[3,2-b]­thiophene (TT) as the conjugated linking unit, were designed and synthesized. The density function theory results manifest that the oxygen atom of the thiophene ester group can form O···S interaction with the sulfur atom. Introducing noncovalent interactions can form multiple intramolecular conformational locks, which greatly enhance the molecular planarity. In addition, 2T2CSi-4F with a symmetrical structure exhibits red-shifted absorption, shallower lowest unoccupied molecular orbital energy levels, and stronger crystallinity than 4T2CSi-4F. Therefore, the PBDB-T:2T2CSi-4F device with favorable molecular packing and morphology achieves a higher power conversion efficiency of 10.04%. Our work demonstrates that the 2T2C unit and multimolecular conformational lock strategy are conducive to the development of efficient NFREAs