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The properties of carbon fiber-reinforced aluminum matrix (CF/Al) composite for aerospace applications are often limited by interfacial reactions. In this study, chemical vapor deposition (CVD) was applied to prepare pyrolytic carbon (PyC) coatings with different thicknesses on CF surfaces to reduce the C/Al interfacial reaction and improve the mechanical properties. Liquid-solid infiltration extrusion (LSIE) was used to prepare CF@PyC/Al composite, and the effects of coating thickness on the interfacial microstructure, tensile properties and fracture behavior were investigated. The experimental results showed that the PyC coating enhanced the oxidation resistance of CF, but the toughness and tensile strength of the CF decreased. The coating effectively suppressed the generation of Al 4 C 3 and provided a better quality interface for the composite. Compared with the uncoated CF/Al composite, the tensile strength of the CF@PyC/Al composite was enhanced by 35% at a coating thickness of about 0.23 μm. In addition, the strength and modulus of the coated material behaved more stably at different layup angles, whereas the uncoated material was more sensitive to angle changes. These performance enhancements are mainly attributed to the effective hindrance of Al 4 C 3 production by the coating, which enhances the crack deflection frequency and enhances the energy absorption capacity. • CVD-deposited PyC coating enhances CF oxidation resistance. • CF@PyC/Al composites exhibit 35% higher tensile strength with 0.23 μm coating. • PyC coating inhibits interfacial reaction, enabling progressive fracture. • Enhanced flexural stability of CF/Al composites by PyC coating to overcome angular sensitivity. [ABSTRACT FROM AUTHOR]

• Advanced stator blade design enhances aero engine efficiency. • Optimization of fiber lay-up, preform preparation, and forming temperature. • Successful preparation of CF/Al composite stator blades at 680°C. • Vibration mode simulations confirm suitability under 1st-order modes. The advancement of high-performance stator blades stands as a critical avenue for enhancing the efficacy of aero engines. This study aims to prepare carbon fiber reinforced aluminum matrix (CF/Al) composite stator blades with high-quality shapes and properties, optimize the lay-up design using Fibersim software, and investigate the effect of extrusion temperature on the forming quality. The mechanical properties and damage behavior were systematically analyzed by tensile, compression, and interlaminar shear tests. In addition, the vibration mode simulation reveals the force state under the 1st to 8th-order vibration modes. Results indicate that the [0°/+45°/0°/-45°/90°/-45°/0°/+45°/0°] lay-up parameters were optimal, achieving excellent shape and performance of curved preforms after curing. Composite blades fabricated at an extrusion temperature of 680°C exhibited clear contours, consistent dimensions, and no macro defects. SEM and EDS analyses showed uniform impregnation in all regions of the blade, high density, and good densification. Compared with the matrix alloy, the tensile strength of the composite blade was improved by 64.94%, the compressive strength by 35.7%, and the interlayer shear strength was as low as 72.6 MPa. The vibration mode simulation verified the applicability of the blade in the first-order vibration mode, which provides strong support for the application of composite materials in the aerospace field. [ABSTRACT FROM AUTHOR]

• This paper provides a non-invasive continuous cerebral blood flow assay that utilizes bioimpedance technology to detect and characterize blood flow regulation in functional brain regions due to neural activity. • The impedance systolic wave height and impedance rise time were used to characterize cerebral blood flow and small artery vasodilatation velocity, quantifying the changes and providing more information for cerebral blood supply studies. • This paper explores the effects of different memory loads on bilateral frontal blood supply and comparatively analyzes the differences in blood supply between bilateral frontal lobes. The cerebral blood supply is crucial for normal brain function. This paper aims to detect and describe alterations in blood supply within functional brain regions during working memory (WM), utilizing bioimpedance technology. Methods: We propose a bioimpedance-based method to detect blood supply to functional brain regions. We introduce the impedance systolic wave height and the impedance rise time to characterize cerebral blood flow (CBF) and small artery vasodilation velocity in functional regions. Lastly, we explore blood supply to frontal lobe regions by utilizing changes in impedance parameters under WM loads. Results: Under low WM load, frontal lobe impedance systolic wave height increased by 0.0051–0.0084 Ω, CBF increased by 14.42–22.24 %, impedance rise time decreased by 0.0332–0.0441 s, and small artery vasodilation velocity increased by 9.80–14.36 %. Under high WM load, the impedance systolic wave height increased by 0.0062–0.0104 Ω, CBF increased by 18.62–30.98 %, impedance rise time decreased by 0.0370–0.0597 s, and small artery vasodilation velocity increased by 12.17–19.42 %. Differences in blood supply between the bilateral frontal lobes due to different WM loads and division of labor between brain regions. Conclusion: The bioimpedance technique is effective in detecting blood supply changes in functional brain regions and quantifying CBF and small artery vasodilation velocity by impedance systolic wave height and impedance rise time, which reveal the differences in blood supply in functional brain regions. The method proposed in this paper provides more information for the study of blood supply in functional brain regions and lays the foundation for further research on bioimpedance detection of brain function. [ABSTRACT FROM AUTHOR]

A comprehensive review of the hydrogen storage systems and investigations performed in search for development of fast refueling technology for fuel cell vehicles are presented. Nowadays, hydrogen is considered as a good and promising energy carrier and can be stored in gaseous, liquid or solid state. Among the three ways, high pressure (such as 35 MPa or 70 MPa) appears to be the most suitable method for transportation due to its technical simplicity, high reliability, high energy efficiency and affordability. However, the refueling of high pressure hydrogen can cause a rapid increase of inner temperature of the storage cylinder, which may result not only in a decrease of the state of charge (SOC) but also in damages to the tank walls and finally to safety problems. In this paper, the theoretical analysis, experiments and simulations on the factors related to the fast refueling, such as initial pressure, initial temperature, filling rate and ambient temperature, are reviewed and analyzed. Understanding the potential relationships between these parameters and the temperature rise may shed a light in developing novel controlling strategies and innovative routes for hydrogen tank fast filling. • Three hydrogen storage systems were presented. Effects of thermo-mechanical were reviewed. • The thermodynamic mechanism of temperature rise and theoretical analysis were reviewed. • The experiments and simulations on fast and safe hydrogen refuelling were summarized. • CFD models on the flow field and temperature field were summarized. • Three safe and fast filling strategies were proposed. [ABSTRACT FROM AUTHOR]

Abstract: Viruses are very widespread in nature, and they cause severe diseases and yield losses in potato production. The transfer of the dsRNA-producing gene could confer a high level virus resistance by specific targeting of cognate viral RNA. In this study, we constructed a marker-free expression vector of a chimeric gene derived from the coat protein sequence of Potato virus X (PVX) and the nuclear inclusion protein sequence of Potato virus Y (PVY) in the form of an intramolecular dsRNA. Then this chimeric gene was introduced into potato cv. Zihuabai, a popular variety in China, via Agrobacterium tumefaciens-mediated transformation. Marker gene-free transgenic plants resistant to both PVX and PVY were obtained and confirmed by RT-PCR and DAS-ELISA detection. Northern blot analysis showed that transgene-derived mRNA was cleaved into short interfering RNAs (siRNAs), and that the virus resistance was mediated by RNA silencing. One important aspect of the study is that the transgenic viral sequence is not translated and the actual RNA transcript is cleaved, which possibly limit the environmental risks, such as transcapsidation and recombination of the transgene with an incoming virus. In addition, the biosafety risk resulting from marker genes can be avoided because of the absence of marker genes in transgenic plants. [Copyright &y& Elsevier]

Developing durable room temperature phosphorescent carbon dot-based materials with high stability and easy preparation has been a great challenge. Here, through a one-step hydrolysis-assisted carbonization treatment, nitrogen-doped carbon dots encapsulated in silica (N-CDs@silica) are obtained, with outstanding stability and durable room temperature phosphorescence (RTP) lifetime (1.81 s, nearly 9 s to naked eye). Further investigations reveal that C O bonds from N-CDs are the main luminescence centers. The formation of Si–O–C bonds covalently linking N-CDs and silica matrice together within silica sphere, as well as the efficient crosslinking effect within N-CDs, are responsible for RTP emission. Based on the unique optical properties of N-CDs@silica, we have developed the RTP strip probe for selective Fe3+ detection. In addition, we explored N-CDs@silica as security ink for advanced anti-counterfeiting. This work not only provides a strategy to synergistically optimizes the structural and luminescent properties of N-CDs@silica in a simple and efficient manner, but more importantly opens a new perspective for developing simple RTP strip probes for sensor applications. [Display omitted] • N-CDs confined in silica were prepared by one-step hydrothermal method. • Efficient crosslinking induced by triethylenetetramine promotes RTP emission. • Room-temperature phosphorescence lifetime reaches 1.81 s. [ABSTRACT FROM AUTHOR]

Ultralong room-temperature phosphorescence (URTP) materials have innate superiority in eliminating autoluminescence for bioimaging, but achieving URTP in aqueous medium is a highly challenging task, especially for carbon dot-based materials. Here we present a facile one-step hydrothermal method to effectively promote RTP emission in an aqueous medium by confining polymer carbon dots (PCDs) in silica nanospheres (SNSs) with tetraethylorthosilicate as only raw material. The polymer carbon dots-silica nanosphere composites (PCDs-SNSs) exhibit ultralong lifetime up to 2.19 s (nearly 9 s to naked eye) at ambient temperature and atmosphere. To the best of our knowledge, this is the longest RTP lifetime of carbon dot-based materials in aqueous media to date. As indicated, RTP should originate from the subfluorescent C O groups. The shielding of SNSs to all kinds of quenching in the confined space in which there are strong interactions between PCDs and SNSs, e.g, covalent bond and hydrogen bond, which enhances the rigidity of cross-linked framework and protects emitting centers from non-radiative deactive processes of triplet state, is the main reason for the URTP observed in aqueous media. Besides, the PCDs-SNSs solution exhibits outstanding stability and low cytotoxicity. Based on the distinctive properties in aqueous media, the PCDs-SNSs have been successfully used as autoluminescence-free probes for bioimaging with high sensitivity and signal-to-noise ratio, and as security ink for strong concealment and moisture-related multilevel information protection. [Display omitted] • Room-temperature phosphorescence lifetime reaches 2.19 s in aqueous media. • Tetraethylorthosilicate is the only raw material. • The phosphorescence originates from polymer carbon dots confined in silica. • Autofluorescence-free bioimaging was achieved. • Multilevel information protection was developed. [ABSTRACT FROM AUTHOR]

Abstract: The upconversion luminescence spectral intensity of Er3+ in Er3+ and Yb3+ codoped ZnO nanocrystals with and without Li+ are investigated. Yb3+ ions as a tradition sensibilizer have efficient energy transfer processes from Yb3+ (2F5/2) to Er3+ (4I13/2, 4I11/2, 4F9/2), which lead to the increment of upconversion luminescence intensity. Following by adding Li+ to the Er3+ and Yb3+ codoped ZnO nanocrystals, the upconversion intensity emitted by Er3+ ions is found greatly enhanced. The enhancement is attributed to the distortion of the local field symmetry of Er3+ ions, so increases various intra-4f transitions of Er3+ ions. Both Yb3+ and Li+ can disperse Er3+ ions in specimen, so reduced the interaction between neighboring Er3+ ions. [Copyright &y& Elsevier]

Abstract: A previous continuum model proposed and recently modified by the authors for describing the heat, mass and momentum transport phenomena in dendrite solidification process of alloy castings was further extended to the solidification cases in an arbitrary electromagnetic (EM)-fields. The extended continuum model and a FEM/FDM joint solution technique were successfully applied to the numerical simulations of directional solidification transport processes in blade-like castings of Pseudo-binary In718 base-4.85wt.%Nb and Al–4.5wt.%Cu alloys under a static or harmonic EM-field of different strengths/frequencies. The computational results demonstrate the availability of the present continuum modeling to treat an EM-STP problem, and also reveal that the volume-contraction-driven liquid feeding flow is much more difficult to be suppressed than the buoyancy-induced by means of applying a static magnetic field. [Copyright &y& Elsevier]