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Purpose This paper aims to focus on the variable stick force-displacement (SFD) gradience in the active side stick (ASS) servo system for the civil aircraft. Design/methodology/approach The problem of variable SFD gradience was introduced first, followed by the analysis of its impact on the ASS servo system. To solve this problem, a linear-parameter-varying (LPV) control approach was suggested to process the variable gradience of the SFD. A H∞ robust control method was proposed to deal with the external disturbance. Findings To validate the algorithm performance, a linear time-variant system was calculated to be used to worst cases and the SFD gradience was set to linear and non-linear variation to test the algorithm, and some typical examples of pitch angle and side-slip angle tracking control for a large civil aircraft were also used to verify the algorithm. The results showed that the LPV control method had less settling time and less steady tracking errors than H∞ control, even in the variable SFD case. Practical implications This paper presented an ASS servo system using the LPV control method to solve the problem caused by the variable SFD gradience. The motor torque command was calculated by pressure and position feedback without additional hardware support. It was more useful for the electronic hydraulic servo actuator. Originality/value This was the research paper that analyzed the impact of the variable SFD gradience in the ASS servo system and presented an LPV control method to solve it. It was applicable for the SFD gradience changing in the linear and non-linear cases.

The Paleo-Asian Ocean (PAO) has been regarded as a long-lived ocean from Neoproterozoic to early Mesozoic, and its subduction and closure built the Central Asian Orogenic Belt (CAOB), the largest accretionary orogenic belt in Earth's history. Although the tectonic evolution of the PAO has been discussed from diverse perspectives, the spatiotemporal dynamics in the evolution of the main branch of the PAO and its relationship with the Tethys remain contentious partly because of the absence of sedimentary evidence. Specifically, as far as the Beishan Orogenic Collage (BOC) in the southernmost part of CAOB is concerned, there remain at least two key questions: how did the BOC evolve tectonically and paleogeographically through the late Paleozoic; and which ophiolitic belt represented the main branch of the PAO in the BOC? This study recognized 27 volcano-sedimentary microfacies and 14 facies associations (FAs) in nine measured Carboniferous–Permian sections from the southern BOC. FA changes in the Visean–Capitanian megasequence indicate a Visean–Moscovian regressive sequence from fore-reef slopes to tidal flats and an Artinskian–Wordian transgressive sequence from fan-deltas to abyssal plains, separated by a continental and volcanic sequence straddling the Gzhelian–Sakmarian interval. Characteristics and lateral correlation of FAs suggest an epicontinental sea during Visean–Moscovian times, followed by a marine rift basin which eventually developed into a proto-oceanic basin during the Artinskian–Wordian. Paleobiogeographic evidence further suggests that this epicontinental sea was closely linked with the Tethyan oceans. Statistical comparisons of detrital zircon ages based on data compiled from previous and the present studies supports that this sea was mainly fed from Neoproterozoic and Ordovician–Silurian rocks (ca. 983 and 425 Ma) with a sparse influx of Mesoproterozoic and Paleoproterozoic detritus (ca. 2492, 1449, and 1302 Ma). During the Artinskian–Wordian, the rift basin was connected with the PAO based on the mixed cool- and warm-temperate marine faunas of the Boreal and Tethyan realms. This rift basin is thought to have been fed by two source-to-sink provenance systems, from either Ordovician–Silurian or Early Permian rocks (ca. 450 or 277 Ma), although provenance signatures were mixed because of turbidity and other currents in deep marine environments. We thus propose a succession of Carboniferous–Permian paleogeographic reconstruction maps for the BOC based on FA correlation and paleobiogeographic features. In these reconstruction models, the PAO is inferred to have been composed of a main branch (an oceanic basin) in the northern BOC as a part of the North Tianshan–Hongshishan–Solonker–Hegenshan Ocean and an epicontinental sea that subsequently evolved into a marine rift basin in the southern BOC.

Exceedingly fast preparation of trifluoromethyl tertiary alcohols has been accomplished from methyl ketones and trifluoromethyl ketones under solvent free conditions by cross Aldol reaction. The reaction was achieved in the presence of common inorganic base by grinding method at ambient temperature to give β -trifluoromethyl- β -hydroxyl ketones in high yields (up to 95%).

Levosimendan is a calcium sensitizer that enhances myocardial contractility without increasing myocardial oxygen use. Limited data are available on its renal-protective effect, and no statistically significant effects have been found. A meta-analysis was conducted for randomized studies to show whether perioperative levosimendan use could reduce acute kidney injury (AKI) in patients undergoing cardiac surgery.BioMed Central, PubMed EMBASE, and the Cochrane Central Register of Controlled Trials were searched for pertinent studies.Randomized trials that compared levosimendan versus placebo or any other control in cardiac surgery with data on AKI were included. Exclusion criteria were duplicate publications, nonadult studies, oral administration of levosimendan, and studies with no data on AKI.Study endpoints, study design, population, clinical setting, levosimendan dosage, and treatment duration were extracted.Data from 529 patients in 5 randomized trials were analyzed. The analysis showed that levosimendan decreased postoperative incidence of AKI in the levosimendan group.This analysis suggests that levosimendan might reduce renal injury in adult patients undergoing cardiac surgery. More prospective randomized studies are needed to further demonstrate the benefits of levosimendan on renal protection in cardiac surgery.