The relationship between rolling-aging sequence and the microstructure evolution, mechanical-electrical properties of hot rolled-quenched Cu-0.67Cr-0.27Zr-0.12Ni-0.03Si-0.04Ti alloy was investigated ...in details and the underlying mechanism of the abnormal decrease in electrical conductivity of the peak-aged alloy by cold rolling was also revealed. The results indicated that a good combination of the tensile strength (585.5 MPa), yield strength (562.1 MPa), Vickers hardness (197.6 HV), and electrical conductivity (67.4 %IACS) was obtained in the Cu–Cr–Zr-based alloy by a sequence of peak aging at 450 °C for 2 h followed by 80% room-temperature rolling and then secondary aging at 400 °C for 1 h. Compared with the rolling-aging process, the strength improvement of the alloy by the aging-rolling-aging process was mainly dominated by dislocation density strengthening. Additionally, a decrease in electrical conductivity of the peak-aged alloy after cold rolling was attributed to the re-dissolution and the refinement of partial coherent precipitates.
The tiger frog (Hoplobatrachus rugulosus) is listed as a national Class II protected species in China. In the context of global warming, the sex ratio of amphibians will be affected, and the ...development of the population will be limited. Therefore, considering the potential for a decrease in the number of amphibians, studying sex evolution and molecular regulation of gonadal development in H. rugulosus, phenomenon that are currently unclear, is of great significance. Here, H. rugulosus was used to explore the mechanisms regulating gonadal development in amphibians. Illumina HiSeq 3000 was used to sequence the gonadal transcriptome of male and female H. rugulosus at two growth stages to identify genes related to gonadal development and analyze expression differences in the gonads. This analysis indicated that cyp17alpha, hsd3beta, hsd11beta1, cyp19alpha, and hsd17beta12 perform vital functions in sex development in amphibians. Specifically, the expression of cyp3alpha, cyp17alpha, hsd3beta, hsd11beta1, sox2, sox9, sox30, soat, cyp19alpha, hsd17beta12, and hspalpha1s was correlated with gonadal development and differentiation in H. rugulosus, as determined using the quantitative reverse transcriptase-polymerase chain reaction. Significant differences were found in the gonadal gene expression levels in H. rugulosus of both sexes, and we identified a steroid hormone synthesis pathway in this species and analyzed related gene expression, but the changes during sex differentiation were still unclear. To our knowledge, this report presents the first analysis of the H. rugulosus gonadal transcriptome and lays the foundation for future research.
This article is concerned with the fixed‐time fault‐tolerant control problem of multiple Euler–Lagrange systems (MELSs) with intermittent communication, actuator faults and input disturbances. A ...nonsingular fixed‐time control framework with three parts is built for the above problem. In the first part, a novel adaptive controller is proposed for MELSs to ensure the fixed‐time stability of sliding modes while successfully solving the actuator faults, parameter uncertainties and unknown disturbances. In the second part, the fixed‐time estimators based on event‐triggered communication are designed by an error decomposition approach. In the third part, an auxiliary system is introduced for the singularity problem and sufficient condition for achieving the consensus is rigorously proved by synthesizing the results of the above two parts. The key feature of the proposed control framework is that the convergence time is constrained by a constant without involving initial states, and the singularity problems of fixed‐time control is avoided. Finally, simulation examples are provided to prove the efficacy of the proposed algorithms.
Isatidis Folium (IF) has been clinically combined with acetaminophen (APAP), but the rationality of combinational therapy is still ambiguous. In the present study, the protective effect and related ...mechanism of IF on APAP‐induced hepatotoxicity were evaluated. Hepatic histopathology and blood biochemistry investigations clearly demonstrated that IF could restore APAP‐induced hepatotoxicity. Liver distribution study indicated that the hepatoprotective effect of IF on APAP is attributed to the reduction of N‐acetyl‐p‐benzoquinone imine (NAPQI) in liver, which is a known hepatotoxic metabolite of APAP. Further study suggested the reduction is not via decreasing the generation of NAPQI through inhibiting the enzyme activities of CYP 1A2, 2E1, and 3A4 but via accelerating the transformation of NAPQI to NAPQI‐GSH by promoting GSH and decreasing GSSG contents in liver. Furthermore, IF significantly enhanced the hepatic activities of GSH‐associated enzymes in APAP‐treated mice. In summary, IF could alleviate APAP‐induced hepatotoxicity by reducing the content of NAPQI via enhancing the level of GSH and the followed generation of NAPQI‐GSH which might be ascribed to the upregulation of GSH‐associated enzymes.
The emergence of flexible organic crystals changed the perception of molecular crystals that were regarded as brittle entities over a long period of time, and sparked a great interest in exploring ...mechanically compliant organic crystalline materials toward next‐generation smart materials during the past decade. Schiff base compounds are considered to be one of the most promising candidates for flexible organic crystals owing to their easy synthesis, high yield, stimuli responsiveness and good mechanical properties. This paper gives an overview of the recent development of Schiff base flexible organic crystals (including elastic organic crystals, plastic organic crystals, and flexible organic crystals integrating elasticity and plasticity) from serendipitous discovery to design strategies and versatile applications such as stimuli responses, optical waveguides, optoelectronic devices, biomimetic soft robots, and organic photonic integrated circuits. Notably, atomic force microscopy‐micromanipulation technique has been utilized to bring the multifunctional applications of flexible organic crystals from the macroscopic level to the microscopic world. Since understanding mechanical flexibility at the molecular level through crystal engineering can assist us to trace down the structural origin of mechanical properties, we focus on the packing structures of various Schiff base flexible organic crystals driven by non‐covalent intermolecular interactions and their close correlation with mechanical behaviors. We hope that the information given here will help in the design of novel flexible organic crystals combined with other unique properties, and promote further research into the area of mechanically compliant organic crystalline materials toward multifunctional applications.
This review provides an overview on the development of Schiff base flexible organic crystals (including elastic organic crystals, plastic organic crystals, and flexible organic crystals integrating elasticity and plasticity) from serendipitous discovery to design strategies and versatile applications such as stimuli responses, optical waveguides, optoelectronic devices, biomimetic soft robots, and organic photonic integrated circuits.
•The thermal performance of lunar regolith thermal reservoir is numerically analyzed.•The evolutional behavior of temperature profile of stacking regolith spheres are presented.•The designed lunar ...regolith thermal reservoir can have the thermal storage density of 0.25 kWh kg−1.•The optimization circular pump pressure is dependent on the stacking method.
As a kind of in-situ resource utilization, the regolith thermal energy storage is a promising way to solve the energy crisis of manmade moon base during the long lunar nighttime of 350 h. In this paper, a lunar regolith thermal storage system is designed and two different stacking methods of lunar regolith spheres are proposed, the thermal storage characteristics of stacked lunar regolith spheres is investigated numerically. The porous media model is applied to simulate the transient temperature and helium flow fields inside regolith thermal reservoir. The influences of regolith sphere diameter and pump pressure on the performance of a lunar regolith thermal reservoir are analyzed. The results show that there exist optimization regolith sphere diameter and pump pressure to the performance of regolith thermal energy reservoir. The optimization circular pump pressure for helium flow is dependent on the stacking method. When the pump pressure increases over 450 Pa, the face centered cubes (FCC) stacking method shows a maximum advantage of 305.6 kWh heat storage amount over the simple cubes (SC) stacking method. The designed lunar regolith thermal reservoir has the thermal storage density of 0.25 kWh kg−1 for one lunar day.
The chiral P,N,N‐ligands represented a new type of tridentate ligand developed in recent years and displayed wide utilities in asymmetric catalysis. In the past decades, numerous chiral P,N,N‐ligands ...with ferrocene, phenethylamine and spiro backbones were synthesized by addition of an aminopyridine, imidazole or diamines coordinating group. These chiral tridentate P,N,N‐ligands showed excellent performance in the ruthenium, iridium, manganese, or cobalt‐catalyzed asymmetric hydrogenations. A wide range of substrates, including simple ketones, α‐halogenated ketones, α‐hydroxy ketones, α‐ or β‐amino keto‐ ones, α‐, γ‐, or δ‐keto acids, α‐ or β‐keto amides, β‐ or δ‐keto esters, α‐ or β‐enones, olefins, imines, quinolines and indoles, could be hydrogenated to afford the corresponding chiral products with high yields and enantioselectivities. In this review, progress on the asymmetric hydrogenation of C=O, C=N, C=C bonds with chiral tridentate P,N,N‐ligands was summarized.
The rolled Ti-6Al-4V alloy sheets were subjected to friction stir processing (FSP) using high heat-input parameters at a tool rotation speed of 325 rpm with a traverse speed of 50 mm/min, and a fully ...lamellar microstructure was obtained in the stir zone (SZ). The high-temperature tensile tests were then conducted on this fully lamellar microstructure in the temperature range of 850–900 °C at the strain rates of 3 × 10-2–3 × 10-4 s-1. The superplasticity with elongations of above 400% was achieved at all the testing temperatures with the appropriate strain rates, and the maximum elongation of 553% was achieved at the temperature of 875 °C and 1 × 10-3 s-1, which was attributed to the dynamic globularization at the low strain stage and subsequent boundary sliding (BS) at the high strain stage. The main dynamic globularization mechanisms were considered as discontinuous dynamic recrystallization (DDRX) and continuous dynamic recrystallization (CDRX) accompanied with the β phase growing towards the inside of the groove along the low angle grain boundaries (LAGBs). The present spheroidized microstructure shows an excellent thermal-mechanical stability because the co-existence of the two phases of α and β could effectively inhibit the severe grain growth and facilitate the continuous operating of the BS. In addition, the β phase transferring from compressive boundaries to tensile boundaries and the strain/stress induced the α to β phase transformation can act as the additional accommodation mechanisms to relax the stress concentration and inhibit the formation of the cavities, which can facilitate the achievement of the enhanced superplasticity.
Whether target organ damage is associated with blood pressure (BP) variability independent of level remains debated. We assessed these associations from 10-minute beat-to-beat, 24-hour ambulatory, ...and 7-day home BP recordings in 256 untreated subjects referred to a hypertension clinic. BP variability indices were variability independent of the mean, maximum-minimum difference, and average real variability. Effect sizes (standardized β) were computed using multivariable regression models. In beat-to-beat recordings, left ventricular mass index (n=128) was not (P≥0.18) associated with systolic BP but increased with all 3 systolic variability indices (+2.97-3.53 g/m(2); P<0.04); the urinary albumin-to-creatinine ratio increased (P≤0.03) with systolic BP (+1.14-1.17 mg/mmol) and maximum-minimum difference (+1.18 mg/mmol); and pulse wave velocity increased with systolic BP (+0.69 m/s; P<0.001). In 24-hour recordings, all 3 indices of organ damage increased (P<0.03) with systolic BP, whereas the associations with BP variability were nonsignificant (P≥0.15) except for increases in pulse wave velocity (P<0.05) with variability independent of the mean (+0.16 m/s) and maximum-minimum difference (+0.17 m/s). In home recordings, the urinary albumin-to-creatinine ratio (+1.27-1.30 mg/mmol) and pulse wave velocity (+0.36-0.40 m/s) increased (P<0.05) with systolic BP, whereas all associations of target organ damage with the variability indices were nonsignificant (P≥0.07). In conclusion, while accounting for BP level, associations of target organ damage with BP variability were readily detectable in beat-to-beat recordings, least noticeable in home recordings, with 24-hour ambulatory monitoring being informative only for pulse wave velocity.
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