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Thermal barrier coatings (TBCs) are facing the challenge of chloride salt hot corrosion in the marine environment. In the manuscript, 7YSZ feather-like columnar structure coatings were prepared by plasma spray-physical vapor deposition (PS-PVD). The Al2O3-modification based on in-situ synthesis was used as the strategy to improve the hot corrosion resistance of the coating. Then, the coatings were subjected to test of 900 °C NaCl thermal exposure and combustion gas-salt spray ablation. The microstructure and phase evolution results of the coatings show that NaCl has a strong corrosive effect on the as-sprayed PS-PVD TBC and leading to catastrophic oxidation. In contrast to this, the Al2O3-modified coating shows good corrosion resistance. In the hot corrosion behavior of NaCl, the metal elements in the bond layer are rapidly oxidized and accumulated on the surface of TGO layer through the electrochemical corrosion mechanism, which makes the TGO thicken rapidly. After combustion gas-salt spray corrosion, the YSZ coatings sintered and the evolution of mechanical properties were analyzed. Compared with the initial sprayed state, the hardness of the as-sprayed coating and the Al2O3-modified coating increased by 13.04 GPa and 11.47 GPa, respectively. And the elastic modulus of as-sprayed coating and Al2O3-modified coating increased by 133.00 GPa and 129.60 GPa, respectively.

Transition metal electrocatalysts with high activity and long durability are desired for methanol oxidation reaction (MOR). Here, the surface fluorinated nickel-graphene nanocomposites (F–Ni–G) are synthesized via the reduction of Si–H bonds produced by silicon and ammonium fluoride in hydrothermal condition. During this process, ionic nickel-F bonds and semi-ionic C–F bonds are introduced to the catalysts as confirmed by X-ray photoelectron spectroscopy. When F–Ni–G nanocomposites are employed as MOR catalysts, the surface fluorination is contributed to the formation of nickelic, which can increase the activity and kinetics for MOR. The onset oxidation potential of F–Ni–G-2 for methanol oxidation is 53 mV lower than that of the Ni/G catalyst without fluorine. The mass activity of F–Ni–G-2 (2493.3 A g−1) is 3.90 folds than that of Ni/G (638.5 A g−1). In addition, the density functional theory calculation indicates that the modified fluorine in graphene results in the decreased reaction energy barrier from ∗CO to ∗COOH step in MOR. The strong electronegativity of F atom makes intermediates easier to attract OH− groups and repel protons, which is conductive to decrease the reaction energy barrier for MOR. Such a facile method for the fabrication of the surface fluorinated catalytic system may be extended to the preparation of other transition metal electrocatalysts.

Excess lead iodide (PbI2) plays a crucial role in passivating the defects of perovskite films and boosting the power conversion efficiency (PCE) of perovskite solar cells (PSCs). However, the photolysis of PbI2 is easily triggered by light illumination, which accelerates the decomposition of perovskite materials and weakens the long-term stability of PSCs. Herein, the high light tolerance of lead iodide (PbI2) is reported by introducing an electron-donor molecule, namely, 2-thiophenecarboxamide (2-TCAm), to strengthen the [PbX6]4- frame. Characterization reveals that the retarded decomposition of PbI2 is attributed to the interactions between Pb2+ and the organic functional groups in 2-TCAm as well as the optimized distribution of PbI2. The crystallization and morphology of 2-TCAm-doped perovskite films are improved simultaneously. The 2-TCAm-based PSCs achieve a 16.8% increase in PCE and nearly 12 times increase in the lifetime as compared to the reference device. The demonstrated method provides insight into the stability of PbI2 and its influence on PSCs.

This paper presents an investigation on vibration characteristics of graphene nanoplatelet (GPL) reinforced disk-shaft rotor with eccentric mass resting on elastic supports. The shaft is made of co...

The term Poincaré beam, which describes the space-variant polarization of a light beam carrying spin angular momentum (SAM) and orbital angular momentum (OAM), plays an important role in various optical applications. Since the radius of a Poincaré beam conventionally depends on the topological charge number, it is difficult to generate a stable and high-quality Poincaré beam by two optical vortices with different topological charge numbers, as the Poincaré beam formed in this way collapses upon propagation. Here, based on an all-dielectric metasurface platform, we experimentally demonstrate broadband generation of a generalized perfect Poincaré beam (PPB), whose radius is independent of the topological charge number. By utilizing a phase-only modulation approach, a single-layer spin-multiplexed metasurface is shown to achieve all the states of PPBs on the hybrid-order Poincaré Sphere for visible light. Furthermore, as a proof-of-concept demonstration, a metasurface encoding multidimensional SAM and OAM states in the parallel channels of elliptical and circular PPBs is implemented for optical information encryption. We envision that this work will provide a compact and efficient platform for generation of PPBs for visible light, and may promote their applications in optical communications, information encryption, optical data storage and quantum information sciences., Well-controlled Poincaré beams are potentially useful in optical communications applications. Here, the authors present phase-only metasurfaces that generate broadband, perfect Poincaré beams in the visible, with radius independent of the topological number.

A structure-based modeling of the CaO−‘FeO’−MgO−Al2O3−SiO2 system and its subsystems was investigated based on iron extraction from nickel slag by aluminum dross. Parameters optimization in the present model indicated that the coefficient of free O2− in FeO, $$a_{{{\text{O}}_{{{\text{FeO}}}}^{{2 - }} }}$$ , on the lengths of network linkage had the largest value and $${\text{O}}_{{{\text{FeO}}}}^{{2 - }}$$ (free O2− in FeO) had the largest mobility. The coefficients of bridging oxygen (aSi−O−Al and aAl−O−Al) were lower than those of non-bridging oxygen and free oxygen (O2−). Viscosity prediction for the CaO−‘FeO’−(8 wt.%) MgO−Al2O3−SiO2 system was conducted at a fixed slag basicity, which indicated that the predicted viscosity changed monotonously with the FeO content. However, the non-monotonous evolution with Al2O3 content reflected the amphoteric behavior of Al2O3. In addition, the performances of the present model in predicting viscosity from binary (‘FeO’−SiO2) to quinary (CaO−‘FeO’−MgO−Al2O3−SiO2) system were analyzed and a comparison with the established models was made.

Three ester-containing gemini surfactants (CmDEGs) were used to construct UV-responsive micellar systems with sodium trans-ortho-methoxycinnamate (trans-NaOMCA) as photo-sensitive additive. The effect of tail-chain length and spacer chain length on the UV-responsive ability was preliminarily explored. Longer tail chain and shorter spacer chain are favorable factors for enhancing UV-responsive ability. The addition of trans-NaOMCA into N,N′-bis(2-(dodecanoyloxy)ethyl)-N,N,N′,N′-tetramethyl-1,3-propane diammonium dibromide (C12DEG3) aqueous solution leads to a peak in zero-shear viscosity (η0) versus composition curve, and its further addition induces aqueous two-phase separation. For the C12DEG3/trans-NaOMCA/H2O mixed micellar systems, the UV responsiveness of significant decrease in η0 ascribes to microstructural transitions arising from the changes in counterion binding modes due to the trans-cis photoisomerization of NaOMCA. In comparison with the gemini surfactant 12-3-12, C12DEG3 has ester groups introduced in its tail chains. The introduction of ester groups leads to a significant effect on enhancing the photo-responsive ability in viscosity decrease of the constructed UV-responsive micellar systems. Furthermore, the effect of the addition of an amino acid–based surfactant sodium lauroylglutamate (SLGlu) into the C12DEG3/trans-NaOMCA/H2O mixed system on the UV-responsive behaviors was explored. In addition to UV-induced significant decrease in η0 and phase transition from aqueous two-phase systems (ATPS) to isotropic single-phase systems, the addition of SLGlu can also cause UV-induced increase in η0 and lead to richer UV-induced phase transition behaviors. The reason leading to these differences due to the presence of SLGlu was discussed based on 1H NMR spectra, molecular dynamics (MD) simulation, and molecular electrostatic potential (MEP) analysis.

Self-assembled lignin nanospheres (LNS) have attracted much attention due to the new opportunities provided for the preparation of value-added products derived from lignin. However, the internal co...

Low back pain associated with degenerative disc diseases has been a major health concern that brings suffering to the patients physically and economically. Many existing therapeutic strategies provide short-term relief of symptoms rather than treatment of the underlying cause. Development of an engineered tissue for disc regeneration is still in its infancy due to the limited autologous healthy disc cell source from the patients. It is also challenging to mimic the complexity of micro-architecture in the native disc tissue that determine their unique structural properties. To date, simple tissue models that mimic the annulus fibrosus (AF) micro-environment for understanding the potential of mesenchymal stem cells (MSCs) in AF tissue engineering are still lacking. In this study, the assembly of a coiled hydrogel microfiber has shown its capability to encapsulate MSCs and create an engineered tissue model that mimics the multiple lamellae of native AF. Using this model, we investigated the potential of MSCs that were previously induced by ascorbic acid (AA). Compared to non-induced MSCs, AA-induced MSCs exhibited significant increase in AF-associated biomarkers during later development in the engineered AF tissue model and also encouraged collagen accumulation through the down-regulated catabolic gene MMP1 and upregulated anti-catabolic gene TIMP1. Furthermore, AA-induced MSCs exhibited a Col2/Col1 ratio closer to that of a native AF tissue. These results suggested that AA-induced MSCs could be a potential cell source for AF tissue engineering and this established tissue model may provide a simple tool for successful AF tissue engineering strategies in the future.

Design and fabrication of high-efficiency electrocatalysts are important to generate hydrogen via urea electrocatalysis with the minimum required energy. In this study, in situ growth of a branch-like Mo-doped Ni3S2 nanoforest on Ni foam was achieved through a facile one-pot hydrothermal process. The as-obtained catalyst exhibited excellent activity and robust durability because of its unique hierarchical nanostructures and doping-optimized electronic structural configuration, and required merely 1.33 V (vs. RHE) and 90 mV (overpotential) to attain a current density of 10 mA cm−2 for the urea oxidation reaction (UOR) and hydrogen evolution reaction (HER), without any noticeable loss in activity even after 120 h of operation. On the basis of the experimental results and theoretical calculations, it was confirmed that the incorporation of Mo in Ni3S2 altered the morphology and electronic structure of the catalyst; hence, more active sites were exposed and the Gibbs adsorption energy of the intermediates in the UOR was optimized. Notably, the overall urea electrolysis cell could afford a low voltage of 1.45 V (vs. RHE) to attain a current density of 10 mA cm−2 and showed excellent durability over 120 h. The findings from this study provide new insights into efficient electrocatalysts for urea electrolyzers, which hold great potential in electrochemical energy conversion and sewage treatment applications.

Organic-inorganic hybrid perovskite has been verified as a suitable semiconductor for hot carrier solar cells via transient absorption spectroscopy. Recently, an internally photoemitted hot carrier (IPHC) solar cell with a novel and innovative structure based on organic-inorganic hybrid perovskite has been achieved. This is a breakthrough in hot carrier study based on perovskite material. To further improve the performance of this newly developed hot electron collection device, a simple and efficient method of adding lithium fluoride (LiF) surface modification layer was applied onto the outmost perovskite layer that benefits both reduction of the trap states and formation of interface dipoles. The IPHC device with LiF modification layer shows a remarkable increase of the short-circuit current density with 20.31% increment. This successful interface engineering proposes a new guideline for further optimizing the performance IPHC and also traditional solar cells based on perovskite.

Different biomedical computing methods for cancer-specific gene recognition have been developed in recent years. Currently, building an open-box machine learning system to discover explainable knowledge from gene expression data is a difficult research problem due to a large number of genes, a small number of samples, and noise. Fuzzy systems can be used to deal with data ambiguity and noise issues and extract meaningful knowledge from gene data. In this article, we create a new deep fuzzy neural network to handle the uncertainty in gene data to generate useful knowledge for specific disease diagnosis. A new hybrid algorithm is designed to preprocess data and select informative genes for accurate cancer detection. Various experiments using six different cancer datasets indicate that the new method has better and more reliable performance than the other conventional classification methods with different gene selection methods.

As a promising candidate for next-generation mobile platforms, virtual reality and augmented reality have the potential to revolutionize the way we perceive and interact with various types of digital information. In the meantime, ultrathin planar liquid crystal polarization optics are enabling a new evolutionary trend in near-eye displays. A recent invited review paper published in eLight provides an insightful review on liquid crystal optical elements and their applications toward AR and VR.

Herein, lignin derived hierarchical porous carbon (LHPC) supported Pd nanoparticles (Pd/LHPC) were synthesized and developed as advanced electrocatalysts for ethanol oxidation. In the Pd/LHPC, the special hierarchical porous carbon with the interconnected micropores and mesopores uniformly distribute on the surface and walls of macropores can provide facile transport for electroactive species and more reaction available surface. The Pd/LHPC exhibits larger specific electrochemically active surface area, higher electrocatalytic activity and better stability toward the oxidation of ethanol than the black carbon (Vulcan XC-72) supported Pd (Pd/XC-72) and commercial Pd/C electrocatalysts. The strategy reported will open a new road to effectively use industrial waste to synthesize advanced carbon material for efficient electrocatalysts and other electrochemical energy-conversion devices.

Mixed A-site engineering is an emerging strategy to overcome the difficulties in realizing high-quality perovskite films together with high ambient stability. Particularly, the α-FACsPbI3-based hybrid perovskites have been considered as a promising candidate for solar cell applications. However, the degradation mechanism of α-FACsPbI3 hybrid perovskites induced by light illumination remains unclear. Here, the illumination-caused instability of α-FACsPbI3 hybrid perovskites is investigated using various surface detection technologies, including photoelectron spectroscopy, scanning electron microscopy, and grazing incidence X-ray diffraction. The experimental findings reveal that the A-site vacancies arise from the migration of Cs+ cations from the perovskite surface into the bulk under light illumination, while their content is dependent on the light energy. The visible light enlarges the crystal lattice on the perovskite surface, leading to the Cs+ cation migration along with the lattice distortion of the PbI64- octahedron and phase separation. However, the ultraviolet light further causes a stronger interaction between FA+ and [PbI6]4-, leading to the partial decomposition of [PbI6]4- into Pb0 and I-. These results enrich the photodegradation mechanism, guiding the design of efficient and stable perovskite solar cells through surface passivation to suppress the Cs+ cation migration and to increase the octahedron dissociation energy.

The dissociation of natural gas hydrate is an endothermic reaction controlled by the heat transfer, which is closely associated with the employed exploitation methods and well configurations. The m...

The visual aesthetic that involves color, brightness, and glossiness is of great importance for building integrated photovoltaics. Semitransparent organic solar cells (ST-OSCs) are thus considered as the most promising candidate due to their superiority in transparency and efficiency. However, the realization of high color purity with narrow bandpass transmitted light usually causes the severely suppressed transparency in ST-OSCs. Herein, we present a spectrally selective electrode (SSE) by imitating the integrating strategy of beetle cuticle for achieving narrow bandpass ST-OSCs with high efficiency and long-term stability. The proposed SSE allows for efficient light-selective passage, leading to tunable narrow bandpass transmitted light from violet to red. An optimized power conversion efficiency of 15.07% is achieved for colorful ST-OSCs, which exhibit color purity close to 100% and a peak transmittance approaching 30%. Long-term stability is also improved for ST-OSCs made with this SSE due to the light-rejecting and the moisture-blocking abilities. The realization of bright and colorful ST-OSCs also indicates the application potential of SSEs in light-emitting diodes, lasers, and photodetectors.

In the paper, ZnO-deposited activated carbon composite (ZnO-AC) was firstly prepared in a simple two-step preparation process, and then covered with nano-graphene oxide to give the NGO-ZnOAC composite. The successful deposition of ZnO and NGO on the AC surface was demonstrated by various experiments, and the ZnO nanoparticles showed a mean diameter size mainly within about 10 nm. The specific surface area of the NGO-AC and NGO-ZnO-AC decreased from 67.74 m²/g of the parent AC to 32.54 and 11.43 m²/g, respectively. The fabricated NGO-ZnO-AC showed excellent adsorptive behaviors towards CrO2-₄ and Cu2+ ions, outperforming both ZnO-AC and AC.

Although perovskite light-emitting diodes (PeLEDs) are promising for next-generation displays and lighting, their efficiency is still considerably below that of conventional inorganic and organic counterparts. Significant efforts in various aspects of the electroluminescence process are required to achieve high-performance PeLEDs. Here, we present an improved flexible PeLED structure based on the rational interface engineering for energy-efficient photon generation and enhanced light outcoupling. The interface-stimulated crystallization and defect passivation of the perovskite emitter are synergistically realized by tuning the underlying interlayer, leading to the suppression of trap-mediated nonradiative recombination losses. Besides approaching highly emissive perovskite layers, the outcoupling of trapped light is also enhanced by combining the silver nanowires-based electrode with quasi-random nanopatterns on flexible plastic substrate. Upon the collective optimization of the device structure, a record external quantum efficiency of 24.5% is achieved for flexible PeLEDs based on green-emitting CsPbBr3 perovskite.

White organic light-emitting diodes (WOLEDs) using thermally activated delayed fluorescence (TADF)-based single emissive layer (SEL) have attracted enormous attention because of their simple device structure and full exciton utilization potential for high efficiency. However, WOLEDs made of an all-TADF SEL usually exhibit serious efficiency roll-off and poor color stability due to serious exciton-annihilation and unbalanced radiative decays of different TADF emitters. Herein, a new strategy is proposed to manipulate the TADF-sensitized fluorescence process by combining dual-host systems of high triplet energy with a conventional fluorescent emitter of complementary color. The multiple energy-funneling paths are modulated and short-range Dexter energy transfer is largely suppressed due to the steric effect of peripheral tert-butyl group in the blue TADF sensitizer. The resulting all-fluorescent WOLEDs achieve an unprecedentedly high external quantum efficiency of 21.8% with balanced white emission of Commission Internationale de l'Eclairage coordinate of (0.292, 0.343), accompanied with good color stability, reduced efficiency roll-off, and prolonged operational lifetime. These findings demonstrate the validity of this strategy for precisely allocating the exciton harvesting in SEL WOLEDs.

Satellites have shown free-space quantum-communication ability; however, they are orbit-limited from full-time all-location coverage. Meanwhile, practical quantum networks require satellite constellations, which are complicated and expensive, whereas the airborne mobile quantum communication may be a practical alternative to offering full-time all-location multi-weather coverage in a cost-effective way. Here, we demonstrate the first mobile entanglement distribution based on drones, realizing multi-weather operation including daytime and rainy nights, with a Clauser-Horne-Shimony-Holt S-parameter measured to be 2.41 ± 0.14 and 2.49 ± 0.06, respectively. Such a system shows unparalleled mobility, flexibility and reconfigurability compared to the existing satellite and fiber-based quantum communication, and reveals its potential to establish a multinode quantum network, with a scalable design using symmetrical lens diameter and single-mode-fiber coupling. All key technologies have been developed to pack quantum nodes into lightweight mobile platforms for local-area coverage, and arouse further technical improvements to establish wide-area quantum networks with high-altitude mobile communication., We demonstrate the first drone-based entanglement distribution under multi-weather conditions, which exhibits the third possible experimental strategy for quantum communication, in addition to fiber and satellite.

The use of bone tissue engineering scaffolds has become a promising potential treatment for bone defects as they expedite bone healing. A carbon nanotube-hydroxyapatite (CNT-HA) composite can accelerate the growth of cells. However, the molecular organized arrangement of organic and inorganic components is one of the most important biochemical phenomena in the formation of bones. This study aimed to prepare ordered CNT-HA scaffolds by applying agarose gel electrophoresis to imitate a biomimetic parallel pattern of collagens and hydroxyapatite hydrogel scaffolds (AG-Col-o-CNT). Significant improvements were presented in the mechanical properties of the scaffolds and cell growth in vitro or in vivo. The results showed that the AG-Col-o-CNT scaffolds accelerated the proliferation and differentiation of bone mesenchymal stem cell lines. In addition, the bone defects were repaired when the scaffolds were transplanted after 28 and 56 days in vivo. The superior performance of the ordered AG-Col-o-CNT scaffolds indicates that they have an enormous potential for bone tissue engineering.

Nickel–zinc (Ni–Zn) batteries are currently regarded as promising energy storage devices due to their high efficiency, high output voltage and good safety. However, the low energy density and poor rate performance caused by insufficient active sites and slow electron/ion transportation impede their future development in large-scale applications. To improve their electrochemical performance, we designed a new Ni-based composite with a unique structure by anchoring Ni–NiO nanoparticles onto a naturally derived and networked cellulose nanofiber carbon (denoted as Ni–NiO/CC), which can work as a robust cathode for Ni–Zn batteries. Benefiting from the elaborate structure that can speed up charge transportation and increase the number of active sites of cathode materials, the capacity of Ni–NiO/CC is remarkably improved from 2.3 mA h g−1 to 184 mA h g−1 at 0.625 A g−1. The as-fabricated Ni–NiO/CC//Zn battery delivers high capacity (256 mA h g−1 at 0.625 A g−1), superior rate performance (68.5% capacity retention at 25 A g−1), and good cycling durability (87.5% retention after 2000 cycles). More importantly, the maximum power density of the Ni–NiO/CC//Zn battery is 41.6 kW kg−1, presenting a peak energy density of 441.7 W h kg−1. This work promotes the facile manipulation of nanostructured electrodes based on sustainable biomass for green and advanced aqueous rechargeable batteries.

A sandwich-type supercapacitor consisting of self-healing layers and electrode layers can easily delaminate during deformation, thereby seriously affecting its reliability. In this work, a type of omni-healable electrode (denoted as CS@PANa–Fe3+–LiCl) is reported, which completely integrates a three-dimensional (3D) electrode material, a self-healing hydrogel and an electrolyte. Consequently, the ease of delamination and the large contact resistance due to the sandwich-type structure can be effectively overcome. Herein, the 3D porous carbon sponge (CS) serves both as an electroactive material and a carrier for the Fe3+-crosslinked sodium polyacrylate–LiCl (denoted as PANa–Fe3+–LiCl) hydrogel electrolyte. Combining the high electrical conductivity and good capacitance of the CS with the high ionic conductivity and excellent self-healability of the PANa–Fe3+–LiCl hydrogel electrolyte, the omnidirectionally integrated electrode exhibits good electrochemical and mechanical properties as well as excellent self-healing characteristics; furthermore, its capacity retention rate remains high (91.6%) even after five cutting/healing cycles. The as-fabricated CS@PA-SC device exhibits full self-healability, high energy density, good cycling stability, and integration characteristics. This investigation offers a facile and versatile strategy to integrate omni-healable electrodes that can be utilized to construct completely self-healable supercapacitors for wearable electronics.

This paper proposes the enhancement of spectral efficiency (SE) by linear polarizer based multilevel linear polarization shift keying (MLPolSK) detection in free-space optical (FSO) communication. At the transmitter end, in order to improve SE of FSO links, the various linear state of polarizations (SOPs) with an equal magnitude-spacing of x- or y-polarization are modulated for MLPolSK signal. At the receiver end, the cascaded polarization-independent semiconductor optical amplifier (SOA) and linear polarizer are introduced to detect MLPolSK signal. Polarization-independent SOA is applied to effectively mitigate the turbulence induced scintillation effect by the gain saturation without the distortion of polarization. Linear polarizer with high extinction ratio (ER) is used to transform various SOPs into the signal with an equal intensity-spacing of x- or y-polarization. Besides, the amplified spontaneous emission (ASE) noises are reduced by the polarization of ASE noises by linear polarizer. Finally, MLPolSK is detected by a single photodiode (PD) and decided by multilevel-thresholdings. In experiments, the performance of the proposed technique is evaluated under turbulence channels, which are emulated using Mach–Zehnder modulator (MZM)-based fading simulator. Experimental results show that the SE is improved up to 3 bit/s/Hz under the effective scintillation mitigation using the proposed technique.

This study investigates the performance of scintillation mitigation for linear polarization shift on-off keying (LPS-OOK) transmission in free-space optical (FSO) communications. Scintillation effect is a critical issue for FSO communication in vertical links. The LPS-OOK signal with orthogonal linear x- and y-polarizations for bits ‘1’ and ‘0’ is modulated and transmitted from the transmitter end. The bits ‘1’ and ‘0’ suffer the scintillation effect in turbulence channel. Based on the orthogonal polarization characteristics of LPS-OOK, linear polarizer (LP) is used to mitigate the scintillation effect on bit ‘0’ by blocking its polarization without the distortion of bit ‘1’. Further, owing to the nonlinear gain characteristics of logarithmic amplification, it is used to equalize the intensity fluctuation of bit ‘1’. Finally, the equalized LPS-OOK is distinguished using fixed threshold decision (FTD) instead of a complex symbol-by-symbol estimation of adaptive threshold. The performance of the proposed technique was verified experimentally for various degrees of the turbulence channel. A Mach–Zehnder modulator (MZM)-based turbulence channel simulator was adopted to accommodate turbulence-induced scintillation effect. The experimental results confirmed that the proposed technique that employed FTD has an improved bit-error-rate (BER) performance compared with that of OOK that employed an adaptive threshold decision (ATD) under various degrees of turbulence channels.

This paper proposes multilevel linear polarization shift keying (MLPolSK) modulation, based on a high polarization-dependent gain optical amplifier (PDG-OA), for spectral efficient free-space optical (FSO) communication. At the transmitter end, multiple linear states of polarization (SOPs) are adopted, and different SOPs are mapped for MLPolSK modulation according to the PDG-OA. First, in the receiver, scintillation is effectively mitigated by a polarization-independent semiconductor optical amplifier (SOA) with gain saturation. Next, various SOPs are transformed into different signal intensity levels by an OA with high PDG characteristics. Finally, transformed signal is directly detected by a single photodiode (PD) with multilevel-thresholds decision. The feasibility of the proposed technique is evaluated experimentally using a reflective semiconductor optical amplifier (RSOA), with a high PDG-up to 20 dB. A Mach–Zehnder modulator (MZM)-based fading simulator is used to accommodate lognormal distribution simulated turbulence effects into experiments. Experimental results illustrate that multilevel linear SOPs can be distinguished effectively by the proposed technique. Consequently, the MLPolSK detection is simplified, and the spectral efficiency (SE) is improved by up to 2 bit/s/Hz with effective scintillation mitigation in FSO.

This study aims to perform free vibration and buckling analyses of circular cylindrical shells made of three-dimensional (3D) graphene foam. Three kinds of porosity distribution are considered incl...

Visual imaging that can extract three-dimensional (3D) space or polarization information on the target is essential in broad sciences and technologies. The simultaneous acquisition of them usually demands expensive equipment and sophisticated operations. Therefore, it is of great significance to exploit convenient approaches for four-dimensional (3D and polarization) visual imaging. Here, we present an efficient solution based on self-assembled asymmetric liquid crystal microlenses, with freely manipulated phase profiles and symmetry-breaking properties. Accordingly, characteristics of multifocal functionality and polarization selectivity are exhibited, along with the underlying mechanisms. Moreover, with a specific sample featured by radially increased unit sizes and azimuthally varied domain orientations, the discriminability of four-dimensional information is extracted in a single snapshot

This paper proposes the dual-wavelength transmission technique for improving the performance of the gain-saturated semiconductor optical amplifier (SOA)-based free-space optical (FSO) communication link. When the gain saturated SOA is used to suppress turbulence-induced scintillation, extinction ratio (ER) degradation effect occurs owing to the high-dynamic gain frequency characteristics for intensity modulation and direct detection (IM/DD) system. The proposed method uses small-spacing dual-wavelength (signal and supplemental wavelengths) transmission to compensate ER degradation by mitigating the gain difference between the bits ‘1’ and ‘0’. Regarding the supplemental wavelength, continuous wave (CW) with various average powers and differential signal (DS) transmissions are experimentally investigated. The proposed technique is evaluated under various turbulence channel strengths. The experimental results show that the bit-error rate (BER) performance is significantly improved via effective ER degradation compensation and scintillation suppression.

This study investigated the improved properties of calcium carbonate (CaCO3) modified urea–formaldehyde (UF) resin adhesive for medium density fiberboard (MDF) production. The CaCO3 modified UF resins were prepared by adding different proportions of CaCO3 to a low molar ratio UF resin at the initial stage of a typical synthetic process of the resin. The physicochemical properties of the resins were measured. The mechanical and environmental performances of the resin-bonded MDF panels were tested. The results show that the viscosity and free formaldehyde content of UF resins with or without CaCO3 modification were not significantly different. The solid content of the CaCO3 modified UF resin was significantly lower than that of the control group. In addition, the measured gel time of the CaCO3 modified UF resin was 111–149 s, which was longer than that of the control resin (82 s). The gel time was further extended with the increase of the CaCO3 content in the UF resin. The chemical group and crystal structure of UF resins with or without the modification of CaCO3 were not significantly different. The internal bonding (IB) strength of the MDF panels significantly increased from 0.75 MPa to 0.97 MPa when the UF resin was modified with 2% of CaCO3. This study provides scientific support for the preparation of inorganic mineral modified UF resins for strength enhanced wood-based panel manufacturing.

This paper proposes a polarization-dependent semiconductor optical amplifier (SOA)-based polarization shift keying (PolSK) modulation for turbulence-robust free-space optical (FSO) communication. Based on the nonlinear gain and polarization characteristics, the PolSK signal is modulated by the optical bit inversion using the polarization-dependent SOA and linear polarizer (LP). The capability of scintillation mitigation is analyzed under both balanced and polarization-independent SOA-based detections. The proposed technique is evaluated in experiments. The experimental results demonstrated that the bit-error-rate (BER) performance of the proposed technique was close to the conventional Mach-Zehnder modulator (MZM)-based PolSK modulation under various scintillation effects.

Monochromatic light can be characterized by its three fundamental properties: amplitude, phase, and polarization. In this work, we propose a versatile, transmission-mode all-dielectric metasurface platform that can independently manipulate the phase and amplitude for two orthogonal states of polarization in the visible frequency range. For proof-of-concept experimental demonstration, various single-layer metasurfaces composed of subwavelength-spaced titanium-dioxide nanopillars are designed, fabricated, and characterized to exhibit the ability of polarization-switchable multidimensional light-field manipulation, including polarization-switchable grayscale nanoprinting, nonuniform cylindrical lensing, and complex-amplitude holography. We envision the metasurface platform demonstrated here to open new possibilities toward creating compact multifunctional optical devices for applications in polarization optics, information encoding, optical data storage, and security.

In this paper, wave dispersion analysis of lipid tubules is presented by using the first-order shear deformation (FSD) shell theory. The small-scale effect is revealed explicitly based on the nonlocal strain gradient theory (NSGT). Different types of lipid tubules with size-dependent material properties are taken into account. Hamilton’s principle is utilized to derive the equations of wave motion. The analytical solutions of phase velocity and wave frequency of propagated waves are obtained. In addition, detailed investigations are implemented to highlight the effects of the types of lipid tubules, the longitudinal and circumferential wave numbers, the material length scale parameters and the nonlocal parameters on the wave dispersion characteristics of lipid tubules.

In this Letter, we propose a novel metasurface conveyor belt with periodic orientated arrays of gold plasmonic elliptical elements (GPEEs), which can be continuously lit in a relay way by switching the polarization of the excitation beam and can be used to trap, transport, and sort particles. The array of the hot field can provide a larger trapping area and better stiffness. With the incident optical intensity of 0.08 m W / µ m 2 , the depth of the potential well could be as high as 10 K B T . By setting a narrow interval between plasmonic ellipses in principal axes, it can help further enhance their directional resonant coupling and polarization dependence. Furthermore, based on consideration of the Brownian motion of trapped particles in aqueous solution, we analyzed its time response property of particle manipulation with different applied switching frequencies from a statistical point of view. As confirmed by numerical analysis, our design offers a novel scheme of particle sorting using a scalable hot spot array with better performance, which could be used in many on-chip optofluidic applications.

Besides the normal hearing pathway known as air conduction (AC), sound can also transmit to the cochlea through the skull, known as bone conduction (BC). During BC stimulation, the cochlear walls demonstrate rigid body motion (RBM) and compressional motion (CPM), both inducing the basilar membrane traveling wave (TW). Despite numerous measuring and modeling efforts for the TW phenomenon, the mechanism remains unclear, especially in the case of BC. This paper proposes a 3D finite element cochlea model mimicking the TW under BC. The model uses a traditional “box model” form, but in a spiral shape, with two fluid chambers separated by the long and flexible BM. The cochlear fluid was enclosed by bony walls, the oval and round window membranes. Contingent boundary conditions and stimulations are introduced according to the physical basis of AC and BC. Particularly for BC, both RBM and CPM of the cochlea walls are simulated. Harmonic numerical solutions are obtained at multiple frequencies among the hearing range. The BM vibration amplitude ( $$U_{{{\text{BM}}}}$$ ) and its relation with volume displacement difference between the oval and round windows $$(\Delta {\text{Vol}})$$ , as well as the pressure difference at the base of the cochlea ( $$P_{{{\text{SV}}}} \left( 0 \right) - P_{{{\text{ST}}}} \left( 0 \right)$$ ), are analyzed. The simulated BM response at 12 mm from the base is peaked at about 3 k Hz, which is consistent with published experimental data. The TW properties under AC and BC are the same and have a common mechanism. (1) $$U_{{{\text{BM}}}}$$ is proportional to $${\Delta }Vol$$ at low frequencies. (2) $$U_{{{\text{BM}}}}$$ is also proportional to $$P_{{{\text{SV}}}} \left( 0 \right) - P_{{{\text{ST}}}} \left( 0 \right)$$ , within 5 dB error at high frequencies such as 16 k Hz. This study partly reveals the common quantitative relations between the TW and related factors under AC and BC hearing.

Polymer memristors with light weight and mechanical flexibility are preeminent candidates for low-power edge computing paradigms. However, the structural inhomogeneity of most polymers usually leads to random resistive switching characteristics, which lowers the production yield and reliability of nanoscale devices. In this contribution, we report that by adopting the two-dimensional conjugation strategy, a record high 90% production yield of polymer memristors has been achieved with miniaturization and low power potentials. By constructing coplanar macromolecules with 2D conjugated thiophene derivatives to enhance the π–π stacking and crystallinity of the thin film, homogeneous switching takes place across the entire polymer layer, with fast responses in 32 ns, D2D variation down to 3.16% ~ 8.29%, production yield approaching 90%, and scalability into 100 nm scale with tiny power consumption of ~ 10−15 J/bit. The polymer memristor array is capable of acting as both the arithmetic-logic element and multiply-accumulate accelerator for neuromorphic computing tasks., Though polymer memristors are promising for low‐power flexible edge computing applications, realizing efficient nanometer‐scale arrays remains a challenge. Here, the authors report a record high 90% production yield in nm‐scale 2D conjugated polymer memristors with homogeneous resistive switching.

The internal structure of carbon aerogels (CAs) is a key factor affecting their electrochemical performance and applications. In this study, the morphology of CAs and their effects on electrochemic...

Nanotherapies combined with stimuli-triggered activated agents have become attractive ways to traditional chemotherapy. The Fe3O4 nanoparticles was employed as the core coated firstly with hydrogels of dually loaded both doxorubicin and hematoporphyrin monomethyl ether. Then, the folic acid was grafted onto the surface of the composites to construct a laser-sensitized magnetic nanoparticles (LMNs), followed by these LMNs being loaded into BC membrane. On the 14th day after treatment, tumor growth inhibition (TGI) was evaluated to 80.38% under the target system. When delivered transdermally under a magnetic field and laser, the synthesized BC/LMNs could offer solutions to challenge in breast cancer treatment, including the limited penetration depth, which could facilitate the bypassing of the stratum corneum barrier and enhance transdermal drug delivery.

None-fullerene solar cells with ternary architecture have attracted much attention because it is an effective approach for boosting the device power conversion efficiency. Here, the crystalline polymer N2200 as the third component is integrated into J71: ITIC bulk heterojunction. A series of characterizations indicate that N2200 could increase photo-harvesting, balanced hole and electron mobilities, enhanced exciton dissociation, and suppressed charge recombination, which result in the comprehensive improvement of open circuit voltage, short circuit current and fill factor in the device. Moreover, after introduction of N2200, the morphology of the ternary active layer is optimized, and the film crystallinity is improved. This work demonstrates that adding a small quantity of high crystallization acceptor into non-fullerene donor: acceptor mixture is a promising strategy toward developing high-performance organic solar cells. Funding Agencies|National Science Foundation of China [11604099, 21875067, 51873138, 51811530011]; Shanghai Rising -Star [19QA1403100]; Shanghai Science and Technology Innovation Action Plan [17JC1402500]; National Key Project for Basic Research of China [2017YFA0303403]; Swedish Research Council [2016-05498]; Swedish Government Strategic Research Area in Materials Science on Advanced Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]; STINT grant [CH2017-7163]

Microemulsions have attracted great interest in the biomedical field involving drug delivery, skin treatment and immune-adjuvant. In any case, microemulsions administered in vivo will more or less contact blood tissue inevitably, however there is no specialized investigation on the interaction between microemulsions and human blood components at cellular and membrane levels. Herein we investigate the effect of a typical microemulsion formulation (Cremophor EL/ethanol/oleinic acid/water (CEOW-ME)) with different extent dilution on human blood components (red blood cells (RBCs), coagulation factor, plasma albumin) and blood coagulation function. It was found that CEOW-ME had a concentration dependent effect on blood components and displayed anti-coagulant activity, causing coagulation factor activation, platelet aggregation impairment and RBC morphology alteration, whereas no impacting on fibrinogen polymerization. Interestingly CEOW-ME had greater influence on the coagulation factors in the plasma related to intrinsic coagulation pathway than extrinsic coagulation pathway. Additionally, spectroscopy studies (DLS, UV-vis, Fluorescence and CD) demonstrated that the impact of CEOW-ME on the size, local micro-structure and conformation of albumin was mediated by hydrophobic binding-induced unfolding and disordering of hierarchical albumin structure. These findings give more comprehensive information for forecasting the potential interaction of the in vivo-administered microemulsions with the cells and bioactive molecules in the human blood.

Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is extensively used as an anode interfacial layer in optoelectronic devices due to its excellent hole-transporting properties and high work function (ϕF). In this study, we propose a simple and cost-effective method to controllably tune the ϕF of PEDOT:PSS from 5.1 eV to 3.95 eV by doping the polyethylenimine ethoxylated (PEIE). The PEIE-doped PEDOT:PSS films can function as a cathode interfacial layer in organic solar cells, showing the comparable performance to a conventional ZnO-based cell. The photoelectric characteristics, surface morphology, and electron transport ability of PEIE-doped PEDOT:PSS films were systematically investigated to elucidate the physical nature of the conversion from hole transport to electron transport. This strategy provides an effective charge transport layer for optoelectronic devices, which is suitable for large-scale, industrial applications.

This study investigates the nonlinear vibration of magnetoelectroelastic composite cylindrical nanoshells embedded in elastic media for the first time. The small-size effect and thermoelectromagnetic loadings are considered. Based on the nonlocal elasticity theory and Donnell’s nonlinear shell theory, the nonlinear governing equations and the corresponding boundary conditions are derived using Hamilton’s principle. Then, the Galerkin method is utilized to transform the governing equations into a nonlinear ordinary differential equation and subsequently the method of multiple scales is employed to obtain an approximate analytical solution to nonlinear frequency response. The present results are verified by the comparison with the published ones in the literature. Finally, an extensive parametric study is conducted to examine the effects of the nonlocal parameter, the external magnetic potential, the external electric potential, the temperature change, and the elastic media on the nonlinear vibration characteristics of magnetoelectroelastic composite nanoshells.

In this paper, free vibration of a metal foam core sandwich (MFCS) beam embedded in Winkler–Pasternak elastic foundation is studied using the Chebyshev collocation method (CCM). This method can achieve high precision within the range allowed by the effective number of bits of computers. Three foam distribution types along the thickness direction are considered for the core. The Timoshenko beam theory is adopted and Hamilton’s principle is utilized to derive the boundary conditions and governing equations of the model. The numerical results show that natural frequencies of the sandwich beam initially increase and then decrease with the rise in thickness of metal foam core. By arranging the foam distribution in the core, natural frequencies of the sandwich beam can be significantly changed. Moreover, natural frequencies of the uniform foam distribution beam are insensitive to the foam coefficient. For the beam with non-uniform foam distribution, however, the natural frequencies increase or decrease with the foam coefficient, depending closely on the foam type. In addition, the present method is validated by comparing with the published ones for special cases.

The design and synthesis of highly efficient thermally activated delayed fluorescence (TADF) emitters with an electroluminescence wavelength beyond 600 nm remains a great challenge for organic light-emitting diodes (OLEDs). To solve this issue, three TADF molecules, xDMAC–BP (x = 1, 2, 3), are developed in combination with the rigid planar dibenzo[a,c]phenazine (BP) acceptor core and different numbers of 9,9-dimethylacridan (DMAC) donors. All these emitters possess stable internal charge transfer and a large dihedral angle between the donors and planar BP core. The emission wavelength can be regulated from 541 to 605 nm by increasing the number of the donor DMAC units because of the controllable tuning of the intramolecular charge transfer effect and the molecular geometrical structure. The photoluminescence quantum yields of these emitters are improved from 42 to 89% with the increase in the number of DMAC units. The orange-red OLEDs employing the xDMAC–BP emitters exhibit maximum external quantum effici...

Preparation of superhydrophobic surfaces capable of recovering both the surface chemistry and hierarchical structure is still a challenge. In this work, all-damage-healable superhydrophobic surface was fabricated by assembly of superhydrophobic and hierarchical BiOCl on lignocellulosic substrates. Fibers having thermally responsive behavior, the main component of lignocellulosic materials, act as the underlying movable substrates. By a simple heating treatment, fibers can convey the undamaged neighbored superhydrophobic coating to the damaged area. In this way, the loss of superhydrophobicity caused by rigorous mechanical destructions, even deep cuts of one hundred of micrometers wide, can be restored, mimicking the self-healing mechanism of human skin. Superior self-healing ability in surface chemistry was also confirmed. Meanwhile, the as-prepared superhydrophobic surfaces demonstrated reliable photocatalytic ability, a useful property for resisting organic contaminations. Interestingly, it was found that the photocatalytic activity can be enhanced by tuning the surface wettability. This work reported the first use of substrate material’s inherently thermally responsive property to demonstrate self-healing superhydrophobic surface with photocatalyticity, which not only promotes the application of superhydrophobic materials in complex environment, but also opens up a new perspective in designing durable superhydrophobic materials.

Poly(3,4-ethylenedioxythiophene)/polystyrene sulfonate (PEDOT:PSS) plays an important role in inverted planar perovskite solar cells (IPPSCs) as an efficient hole extraction and transfer layer (HTL). The IPPSCs based on PEDOT:PSS normally display inferior performance with a reduced open-circuit voltage. To address this problem, here sodium citrate-doped PEDOT:PSS is adopted as an effective HTL for improving the performance of IPPSCs. Sodium citrate-doped PEDOT:PSS HTL improves the conversion efficiency of IPPSCs from 15.05% of reference cells to 18.39%. The large increase of the open-circuit voltage ( VOC) from 1.057 to 1.134 V is the main source for this performance enhancement. With the help of characterization analysis of ultraviolet photoelectron spectroscopy, scanning electron microscopy, electrochemical impedance spectroscopy, etc., the higher work function of the doped PEDOT:PSS film and the uniform crystallinity of the perovskite film on it are disclosed as the reasons for the increased VOC and the consequent performance enhancement.

NiO thin films have been widely studied recently due to their intrinsic p-type conductivity and potential applications in various domains as transparent conductive oxides. However, the intrinsic p-type resistivity (ρ) of NiO is as high as 1013 Ω·cm, which needs to be optimized. In the current work, we devised an experiment to improve the electrical properties of NiO films through three methods: 1) encouraging monovalent Cu+ ions to substitute for Ni2+ ions in NiO:Cu films deposited from NiO-Cu composite targets; 2) introducing nickel vacancies and interstitial oxygen in the films deposited by oxygen ion assisted rf sputtering in Ar + O2 mixture; 3) adding group-V element N to replace O by employing Ar + N2 mixture as the sputtering gas. The results show that the first two methods can effectively enhance the film's p-type conductivity, while the carrier concentration in the films improves greatly. However, the last method reveals that when N atoms are introduced into NiO:Cu films they will reduce the film's p-type electrical properties. This indicates that N doping hinders the hole generation under our experimental conditions.

The nonlinear vibration characteristics of the piezoelectric circular cylindrical nanoshells resting on a viscoelastic foundation are analyzed. The small scale effect and thermo-electro-mechanical loading are taken into account. Based on the nonlocal elasticity theory and Donnell’s nonlinear shell theory, the nonlinear governing equations and the corresponding boundary conditions are derived by employing Hamilton’s principle. Then, the Galerkin method is used to transform the governing equations into a set of ordinary differential equations, and subsequently, the multiple-scale method is used to obtain an approximate analytical solution. Finally, an extensive parametric study is conducted to examine the effects of the nonlocal parameter, the external electric potential, the temper-ature rise, and the Winkler-Pasternak foundation parameters on the nonlinear vibration characteristics of circular cylindrical piezoelectric nanoshells.

In this study, the thermo-hygro-mechanical bending and vibration of functionally graded material (FGM) microbeams with microporosity defect are investigated. The mathematical model of the system is developed by using the sinusoidal beam theory and the modified couple stress theory. Based on Hamilton’s principle, the governing equations and boundary conditions of imperfect FGM microbeams are derived. Then, Navier’s method is utilized to calculate the deflections and natural frequencies of the system. Analytical results are presented to illustrate the effects of the microporosity volume fraction, the microporosity distribution type, the power-law index, the temperature and the moisture on the static bending and free vibration of imperfect FGM microbeams.