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Three-dimensional (3D) printing has emerged as an attractive manufacturing technique because of its exceptional freedom in accessing geometrically complex customizable products. Its potential for mass manufacturing, however, is hampered by its low manufacturing efficiency (print speed) and insufficient product quality (mechanical properties). Recent progresses in ultra-fast 3D printing of photo-polymers1–5have alleviated the issue of manufacturing efficiency, but the mechanical performance of typical printed polymers still falls far behind what is achievable with conventional processing techniques. This is because of the printing requirements that restrict the molecular design towards achieving high mechanical performance. Here we report a 3D photo-printable resin chemistry that yields an elastomer with tensile strength of 94.6 MPa and toughness of 310.4 MJ m−3, both of which far exceed that of any 3D printed elastomer6–10. Mechanistically, this is achieved by the dynamic covalent bonds in the printed polymer that allow network topological reconfiguration. This facilitates the formation of hierarchical hydrogen bonds (in particular, amide hydrogen bonds), micro-phase separation and interpenetration architecture, which contribute synergistically to superior mechanical performance. Our work suggests a brighter future for mass manufacturing using 3D printing.

Bilayer hydrogels with intelligent functions have been considered as the ideal candidates for mimicking soft tissues and robots to adapt their shapes or motions in response to external stimuli. However, conventional fabrication strategies often require multiple complicated steps to create an anisotropic bilayer structure with poor structural defect tolerance due to chemo-mechanical mismatch between two layers. Herein, we report a new working principle and fabrication strategy to construct a family of bilayer hydrogels with a seamless interface and programmable layer thicknesses by controlling spontaneous macrophase separation. The macrophase separation mainly stems from different heat-induced reversible phase transitions of both polymer layers, allowing the decoupling of two gelation processes for the first polymer layer via a typical sol-to-gel transition and the second layer via a spontaneous hydrophilic-to-hydrophobic separation. This work demonstrates a new working principle for seamless integration of thermal-responsive polymers with macrophase separation to create hydrogels with multi-scale hierarchical structures.

TiO2has demonstrated outstanding performance in electrochemical advanced oxidation processes (EAOPs) due to its structural stability and high oxygen overpotential. However, there is still much room for improving its electrochemical activity. Herein, narrow bandgap manganese oxide (MnOx) was composited with TiO2nanotube arrays (TiO2NTAs) that in-situ oxidized on porous Ti sponge, forming the MnOx-TiO2NTAs anode. XANES and XPS analysis further proved that the composition of MnOxis Mn2O3. Electrochemical characterizations revealed that increasing the composited concentration of MnOxcan improve the conductivity and reduce oxygen evolution potential so as to improve the electrochemical activity of the composited MnOx-TiO2NTAs anode. Meanwhile, the optimal degradation rate of benzoic acid (BA) was achieved using MnOx-TiO2NTAs with a MnOxconcentration of 0.1 mmol L−1, and the role of MnOxwas proposed based on DFT calculation. Additionally, the required electrical energy (EE/O) to destroy BA was optimized by varying the composited concentration of MnOxand the degradation voltage. These quantitative results are of great significance for the design and application of high-performance materials for EAOPs.

The acoustically actuated magnetoelectric (ME) microantenna integrated on a film bulk acoustic resonator (FBAR) has exhibited a potential for communication and wireless sensing applications owing to the breakage of traditional antenna size limitation. However, the development is still at infancy, and much is unknown and unclear for the design of the ME microantennas and material selection. This article presents a finite element analysis-based method and a magnetic dipole model to analyze the radiation characteristics of ME antenna. The effects of piezoelectric (PE) and magnetostrictive (MS) materials and their thicknesses, shape, and area of the electrode, and damping factor of the MS material on the radiation characteristics of ME antenna are investigated in detail. Results show that with an optimized design and proper materials combination, FBARs with an ME microantenna of the size $200\,\, {}\times {}200\mu \text{m}$ could emit electromagnetic waves over 30 m with a maximum radiation power of up to $3.4\,\, {}\times {}10^{-7}$ W (−34.7 dBm), suitable for short-range communication and wireless sensing applications, demonstrating a great potential of the ME microantennas.

Chitin oligosaccharides (CHOS), high-value-added oligomers linked by N-acetyl-d-glucosamine (GlcNAc, NAG), and a small amount of d-glucosamine (GlcN, GA), have aroused increasing interest due to their excellent biological properties, including antibacterial, anti-inflammatory, and immunoprotective activities, and intestinal regulation. The efficient production and utilization of CHOS with high performance can solve problems from chitin as biowaste. However, the large-scale production of well-defined CHOS has not been fully accomplished due to the limited biotechnology and separation methods, thus impeding the research on their biological functions as well as their accurate applications. In this review, we comprehensively summarize the current preparation methods of CHOS, including the chemical, physical, enzymatic and biosynthetic methods. The advantages and disadvantages of the methods are discussed in terms of efficiency, economy, and environmental effects. Furthermore, the applications of CHOS in the food industry and their contributions to human health based on their excellent bioactivities are expounded. It is hoped that this review will help in providing new insights into the production of CHOS with high precision, and support the application of CHOS in serving the food industry as nutritional supplements or foods for special medical purposes.

Self-powered real-time wireless sensor networks (WSNs) are vital for smart manufacturing, intelligent healthcare, and smart cities etc. Various nanogenerators have extensively exploited for powering these systems. Compared with triboelectric nanogenerators (TENGs), piezoelectric nanogenerators (PENGs) have smaller dimensions and can be easier to integrate into ICs, offering broader applications. However, fully self-powered instantaneous wireless sensor systems with PENGs are yet to be realized. Here, we present a PENG based, self-powered, instantaneous wireless (PSIW) sensor system. The integration of the PENG with an RLC sensing circuit facilitates the spontaneous generation of oscillating signals with encoded sensing information. To address the high internal impedance issue of PENGs, a piezoelectric voltage driven electronic switch is employed, ensuring that the oscillating signal's frequency and amplitude remain highly stable. The effects of variables on signal frequency are investigated in detail. The sensor system is utilized to sense bending (strain), and to monitor physical actions such as elbow swing, wrist bending, walking, running etc. Results showed that the PSIW sensor system can effectively monitor strain and bending angles, and judiciously detect body’s physical movements. By employing either frequency-based or amplitude-based sensing methods, the PSIW sensor system demonstrates versatility and adaptability for various sensing applications.

Droplet vibration nanogenerator is a promising technology that can transform kinetic energy into electric energy. In this paper, a vibration droplet nanogenerator based on lead zirconate titanate (PZT) (PZT-VDNG) is proposed, which utilizes the change in double electron layer area at the droplet/PZT interface, hence an extraordinary charge variation, induced by mechanical vibrations. Our approach innovatively combines a high fixed surface charge density with ionic solutions to significantly enhance energy conversion efficiency. A theoretical model of the PZT-VDNG is established, showing excellent consistence with the experimental results. The energy conversion efficiency and its correlation with the materials involved, device structure and circuits used, are investigated in detail. Under the optimal conditions of a vibration frequency of 5 Hz, an amplitude of 2 mm, and a droplet size of 40 μL, a short-circuit current output of 31.43 μA and an open-circuit voltage of 1.5 V are obtained by a single vibration of a droplet, respectively, 111 and 37.5 times larger as compared to those from a VDNG with PTFE polymer layer. This marks a significant leap in the efficiency and potential applications of vibration nanogenerators.

Living organisms can generate diverse three-dimensional (3D) morphologies and programmatically regulate their morphological evolution via the neurally controlled expansion and contraction of soft tissues. Although polymeric hydrogels have been regarded as an ideal experimental platform for biomimetic morphing due to their soft-tissue-like properties, it is still a tricky problem to quantitatively design their 3D morphological evolution, especially for inert polymeric hydrogels. In this study, we developed a muscle-inspired deformation system that could programmatically regulate the morphological evolution of undeformable inert polymeric hydrogels using large-deformable hydrogels as muscles, which contained smart poly N-isopropylacrylamide (PNIPAm) microgel and could be anchored onto any hydrogels via interfacial diffusion polymerization (IDP). Moreover, by programmatically regulating the anchoring position of the large-deformable muscle, the 3D morphology of kirigami-shaped hydrogels could further evolve to obtain a more complex 3D morphology. Surprisingly, when the inert hydrogel was replaced by a shape-memory hydrogel, the 3D morphologies could be fixed and preserved for more than 1 month without any stress relaxation or swelling, even after removing the hydrogel muscle or external stimuli. Therefore, we believe that this deformation strategy will enhance our understanding of the life evolution of natural soft-wet organisms for developing intelligent soft materials such as shape-memory hydrogels, programmable deformations, and 3D biomimetic devices.

Tendinopathy is a common musculoskeletal disease for which researchers have proposed various treatments but with limited efficacy. Here, we propose a self-powered wearable electrical stimulation (ES) patch with an integrated triboelectric nanogenerator (TENG) for tendinopathy treatment. The ES patch comprises a freeze-dried PVDF-TrFE/PA6 TENG and a pair of interdigital electrodes (IDTs). The bionically designed ES patch is attached directly to affected tendons. It undergoes deformation and friction during movement and generates pulsed electric output, which is then converted into an electric field via the IDTs to treat tendinopathy. In vitro experiments showed that the self-powered ES patch greatly increased mitochondrial function in degenerative tendon stem/progenitor cells (TSPCs) and promoted tenogenesis. In vivo experiments revealed that the ES patch significantly improved the gait motor function of tendinopathy rats, boosted collagen regeneration, and drastically reduced the degree of tissue inflammatory infiltration and recovery time. Our study demonstrated the great potential of wearable electrical stimulation patches for effectively treating tendinopathy.

Reducing energy use is crucial to commercialize electrochemical oxidation technologies. We developed a three-dimensional (3-D) electrochemical system that can significantly reduce the applied voltage and effectively degrade organic contaminants in low-ionic-strength wastewaters. The 3-D system consisted of a composite wire mesh anode (composed of blue TiO2nanotubes covered with SnO2–Sb2O3), a proton exchange membrane, and a stainless-steel wire mesh cathode, which were compressed firmly together. For the 3-D system, we placed the anode of a 3-D electrode toward the wastewater that flowed past the anode. Both the two-dimensional (2-D) and 3-D systems had the same anode and cathode. We found that the 3-D system could reduce the applied voltage by 75.7% and reduce the electrical efficiency per log order reduction (EE/O) by 73% for 0.001 M Na2SO4. For Na2SO4concentrations greater than 0.05 M, the 2-D system had a slightly lower EE/O. We also compared the EE/O of electrochemical advanced oxidation processes (EAOPs) with that of other advanced oxidation processes (UV/H2O2, UV/persulfate, O3/H2O2, UV/ TiO2, and UV/chlorine). We found that EAOPs have a much higher EE/O for low BA concentrations (20 mg/L) and a much lower EE/O for high BA concentrations (2000 mg/L).

This paper investigates a trajectory tracking control method for multi-underactuated underwater vehicle (AUV) formations with uncertain model parameters and external environmental disturbances. Firstly, a dual closed-loop fixed-time integral sliding mode controller is designed. By combining fixed-time theory and integral sliding mode control, this controller ensures the stability of the formation tracking and guarantees the convergence of the tracking error to zero within a fixed time duration. Secondly, an adaptive radial basis function (RBF) neural network controller is integrated with a conditional integrator to address uncertainties in model parameters, approximation errors, and external environmental disturbances in practical multi-AUV systems. This controller exhibits robustness and adaptivity. Additionally, a virtual leader strategy is employed to enhance the robustness of the formation system and prevent formation collapse caused by leader AUV failures. Finally, simulation results validate the effectiveness of the proposed formation controller, demonstrating accurate trajectory tracking by the AUV formation.

Increasing numbers of cement furnaces have applied selective catalytic reduction (SCR) units for advanced treatment of NO in the flue gas. However, the SCR catalysts may face various poisons, such as acidic, alkaline, and heavy metal species, in the fly ash. In this work, we studied the deactivation mechanisms of multipoisons (Ca, Pb, and S) on the CeO2–WO3/TiO2catalyst, using the in situdiffuse reflectance infrared Fourier transform spectroscopy method. Calcium promoted the conversion of Ce(III) to Ce(IV) and, thus, (i) suppressed the redox cycle, (ii) decreased the NO adsorption (monodentate NO3–and bridged NO2–), and (iii) enriched the Lewis acid sites. Pb(IV) blocked Ce2(WO4)3, aggravating the electronegativity of W6+, which inhibited (i) the binding stability of tungsten and ammonia species, (ii) bridged NO3–(bonded to tungsten), and (iii) the Brønsted acid sites. The multipoisoning processes enriched O2–by repairing partial surface oxygen defects, which suppressed O22–and O–. Sulfur occupied the surface base sites and formed PbSO4after Ce2(WO4)3was saturated.

Polysulfides shuttle, although is not the only one, but definitely the most prominent problem which hinders the commercialization of lithium-sulfur cells. Herein, a functionally designed SiO2tethered 1-methyl-1-propylpiperidinium chloride (SiO2-PPCl) ionic liquid nanoparticle is adopted as a bridgebuilder between the carbon carrier and lithium polysulfides (LPS) to modulate shuttle issues. The SiO2-PPCl exerts effective adhesion to both polar LPS and nonpolar carbon carrier material by its special function groups, which make it act as a bridge between them, therefore, the dissolved LPS are prevented from migrating to lithium anode effectively, and the corresponding LPS shuttle is controllable by simply tuning the ratio of SiO2-PPCl to sulfur. This strategy is demonstrated in a lithium sulfur suspension flow cell in which the shuttle effect is more serious because large quantity of electrolyte is adopted, and over 1000 cycles is achieved with high coulombic efficiency of 99%. Verified in a laboratory flow cell equipment, the approach of exploiting polysulfides bridgebuilder to control LPS shuttle manifests its feasibility and offers a new direction to develop lithium-sulfur batteries.

Substrates able to rectify transport of ions based on charge and/or size are ubiquitous in biological systems. Electrolytes and interphases that selectively transport electrochemically active ions are likewise of broad interest in all electrical energy storage technologies. In lithium-ion batteries, electrolytes with single- or near-single-ion conductivity reduce losses caused by ion polarization. In emergent lithium or sodium metal batteries, they maintain high conductivity at the anode and stabilize metal deposition by fundamental mechanisms. We report that 20- to 300-nm-thick, single-ion-conducting membranes deposited at the anode enable electrolytes with the highest combination of cation transference number, ionic conductivity, and electrochemical stability reported. By means of direct visualization we find that single-ion membranes also reduce dendritic deposition of Li in liquids. Galvanostatic measurements further show that the electrolytes facilitate long (3 mAh) recharge of full Li/LiNi0.8Co0.15Al0.05O2(NCA) cells with high cathode loadings (3 mAh cm−2/19.9 mg cm−2) and at high current densities (3 mA cm−2).

An empirical simulation method to simulate the possible position of shallow rainfall-induced landslides in China has been developed. This study shows that such a simulation may be operated in real-time to highlight those areas that are highly prone to rainfall-induced landslides on the basis of the landslide susceptibility index and the rainfall intensity-duration (I-D) thresholds. First, the study on landslide susceptibility in China is introduced. The entire territory has been classified into five categories, among which high-susceptibility regions (Zone 4- ‘High’ and 5-‘Very high’) account for 4.15% of the total extension of China. Second, rainfall is considered as an external triggering factor that may induce landslide initiation. Real-time satellite-based TMPA 3B42 products may provide real rainfall spatial and temporal patterns, which may be used to derive rainfall duration time and intensity. By using a historical record of 60 significant past landslides, the rainfall I-D equation has been calibrated. The rainfall duration time that may trigger a landslide has resulted between 3 hours and 45 hours. The combination of these two aspects can be exploited to simulate the spatiotemporal distribution of rainfall-induced landslide hazards when rainfall events exceed the rainfall I-D thresholds, where the susceptibility category is ‘high’ or ‘very high’. This study shows a useful tool to be part of a systematic landslide simulation methodology, potentially providing useful information for a theoretical basis and practical guide for landslide prediction and mitigation throughout China.

We present a novel iontronic barometric pressure sensor based on a gel polymer electrolyte and interdigital electrodes with a much simpler structure than that of existing devices. By introducing high-density microstructures on the gel polymer electrolyte and one side electrode arrangement configuration, the developed sensor offers high performances with an ultrahigh resolution of 10 Pa, an ultrawide barometric pressure-response range from −92 to 7 kPa, a fast response time of ∼15 ms, and excellent long-term stability. The single pressure sensor is able to detect positive and negative barometric pressures without needing any additional means and can operate as a barometric altimeter with a resolution of about one-floor height. The performances of the sensors significantly surpass those of existing barometric pressure sensors. This work provides a new strategy for making high-performance barometric pressure sensors that are highly sought for commercial applications such as altitude detection, negative pressure ambulance, and consumer electronics.

Here we demonstrate a triboelectric nanogenerator (TENG) based fully self-powered multi-parameter wireless sensing system. By integrating the TENG with multiple mutually coupled RLC resonators, the energy harvested by the TENG is directly converted into a decaying oscillating signal containing multiple frequency components with encoded sensing information. The oscillating signals can be transmitted and received by the near-field antennas using inductive coupling and the wireless sensing distance is up to 2 m. A theoretical analysis method based on characteristic parameters is proposed firstly, which is used to obtain the functional expressions between the attenuation coefficients α, eigen frequencies ωand characteristic parameters. Fast Fourier transform (FFT) spectral analysis is used to extract multi-parameters, shows that the theoretical analysis agrees very well with the experimental results. A self-powered wireless strain distribution sensing system based on LabVIEW was developed to demonstrate the feasibility of the proposed multi-parameter sensing technology, the results show that the system can monitor strains and its distribution along a cantilever-like structure precisely, demonstrating its great application potential.

Heat dissipation involved safety issues are crucial for industrial applications of the high-energy density battery and fast charging technology. While traditional air or liquid cooling methods suffering from space limitation and possible leakage of electricity during charge process, emerging phase change materials as solid cooling media are of growing interest. Among them, paraffin wax (PW) with large latent heat capacity and low cost is desirable for heat dissipation and thermal management which mainly hindered by their relatively low thermal conductivity and susceptibility to leakage. Here, highly ordered and interconnected hexagonal boron nitride (h-BN) networks were established via ice template method and introduced into PW to enhance the thermal conductivity. The composite with 20 wt% loading amount of h-BN can guarantee a highly ordered network and exhibited high thermal conductivity (1.86 W m−1 K−1) which was 4 times larger compared with that of random dispersed h-BN involved PW and nearly 8 times larger compared with that of bare PW. The optimal thermal conductive composites demonstrated ultrafast heat dissipation as well as leakage resistance for lithium-ion batteries (LIBs), heat generated by LIBs can be effectively transferred under the working state and the surface temperature kept 6.9 °C lower at most under 2–5 °C continuous charge-discharge process compared with that of bare one which illustrated great potential for industrial thermal management.

Fake news is spreading rapidly on social media and poses a serious threat to the COVID-19 outbreak response. This study thus aims to reveal the factors influencing the acceptance of fake news rebuttals on Sina Weibo. Drawing on the elaboration likelihood model (ELM), we used text mining and the econometrics method to investigate the relationships among the central route (rebuttal's information readability and argument quality), peripheral route (rebuttal's source credibility, including authority and influence), and rebuttal acceptance, as well as the moderating effect of receiver's cognitive ability on these relationships. Our findings suggest that source authority had a negative effect on rebuttal acceptance, while source influence had a positive effect. Second, both information readability and argument quality had positive effects on rebuttal acceptance. In addition, individuals with low cognitive abilities relied more on source credibility and argument quality to accept rebuttals, while individuals with high cognitive abilities relied more on information readability. This study can provide decision support for practitioners to establish more effective fake news rebuttal strategies; it is especially valuable to reduce the negative impact of fake news related to major public health emergencies and safeguard the implementation of anti-epidemic strategies., Competing Interests: The author(s) declared no potential conflicts of interest concerning the research, authorship, and/or publication of this article., (© 2021 Published by Elsevier Ltd.)