Printed electronics on elastomer substrates have found wide applications in wearable devices and soft robotics. For everyday usage, additional requirements exist for the robustness of the printed ...flexible electrodes, such as the ability to resist scratching and damage. Therefore, highly robust electrodes with self‐healing, and good mechanical strength and stretchability are highly required and challenging. In this paper, a cross‐linking polyurea using polydimethylsiloxane as the soft segment and dynamic urea bonds is prepared and serves as a self‐healing elastomer substrate for coating and printing of silver nanowires (AgNWs). Due to the dynamic exchangeable urea bond at 60 °C, the elastomer exhibits dynamic exchange of the cross‐linking network while retaining the macroscopic shape. As a result, the AgNWs are partially embedded in the surface of the elastomer substrate when coated or printed at 60 °C, forming strong interfacial adhesion. As a result, the obtained stretchable electrode exhibits high mechanical strength and stretchability, the ability to resist scratching and sonication, and self‐healing. This strategy can be applied to a variety of different conducting electrode materials including AgNWs, silver particles, and liquid metal, which provides a new way to prepare robust and self‐healing printed electronics.
A concept involving preparing stretchable, robust, and self‐healing electrodes via a direct surface printing on a polyurea elastomer is developed in this work. Taking advantage of the dynamic polyurea's kinetic chain movement at an elevated temperature, variable conductive nano‐fillers can be self‐embedded into the elastomer's surface without shape changing, exhibiting high significance in designing both robust and self‐healing electrodes.
As a critical part of flexible electronics, flexible circuits inevitably work in a dynamic state, which causes electrical deterioration of brittle conductive materials (i.e., Cu, Ag, ITO). Recently, ...gallium‐based liquid metal particles (LMPs) with electrical stability and self‐repairing have been studied to replace brittle materials owing to their low modulus and excellent conductivity. However, LMP‐coated Ga2O3 needs to activate by external sintering, which makes it more complicated to fabricate and gives it a larger short‐circuit risk. Core–shell structural particles (Ag@LMPs) that exhibit excellent initial conductivity(8.0 Ω sq−1) without extra sintering are successfully prepared by coating nanosilver on the surface of LMPs through in situ chemical reduction. The critical stress at which rigid Ag shells rupture can be controlled by adjusting the Ag shell thickness so that LM cores with low moduli can release, achieving real‐time self‐repairing (within 200 ms) under external destruction. Furthermore, a flexible circuit utilizing Ag@LMPs is fabricated by screen printing, and exhibits outstanding stability and durability (R/R0 < 1.65 after 10 000 bending cycles in a radius of 0.5 mm) because of the functional core–shell structure. The self‐repairable Ag@LMPs prepared in this study are a candidate filler for flexible circuit design through multiple processing methods.
A novel core–shell conductive particle based on liquid metal (Ag@LMPs) is developed. This particle exhibits excellent conductivity without external sintering, while simultaneously exhibiting long‐term durability and real‐time self‐repairing in flexible circuits owing to the release of the liquid metal core. These Ag@LMPs are a candidate filler for self‐repairing flexible circuit design.
All-solid-state lithium-based batteries with inorganic solid electrolytes are considered a viable option for electrochemical energy storage applications. However, the application of lithium metal is ...hindered by issues associated with the growth of mossy and dendritic Li morphologies upon prolonged cell cycling and undesired reactions at the electrode/solid electrolyte interface. In this context, alloy materials such as lithium-indium (Li-In) alloys are widely used at the laboratory scale because of their (electro)chemical stability, although no in-depth investigations on their morphological stability have been reported yet. In this work, we report the growth of Li-In dendritic structures when the alloy material is used in combination with a Li
PS
Cl solid electrolyte and Li(Ni
Co
Mn
)O
positive electrode active material and cycled at high currents (e.g., 3.8 mA cm
) and high cathode loading (e.g., 4 mAh cm
). Via ex situ measurements and simulations, we demonstrate that the irregular growth of Li-In dendrites leads to cell short circuits after room-temperature long-term cycling. Furthermore, the difference between Li and Li-In dendrites is investigated and discussed to demonstrate the distinct type of dendrite morphology.
The sluggish layered structural sodium reaction kinetics and the easy restacking property are major obstacles hindering the practical application of MoS2-based electrodes for sodium storage. Herein, ...covalently assembled two-phase MoS2–SnS supported by a hierarchical graphitic carbon nitride/graphene (MoS2–SnS@g-C3N4/G) composite is constructed to improve cycling cyclability and rate performances for Na storage. The multiphase MoS2–SnS@g-C3N4/G is featured with a covalent assembly strategy and an interconnected network architecture. This unique structural design can not only enhance the conductivity and facilitate fast interfacial electron transport, which is confirmed by experiments and density functional theory, but also buffer the volumetric changes of MoS2–SnS. As a result, the as-obtained MoS2–SnS@g-C3N4/G anode delivers a high reversible capacity of 834 mA h g–1 at 0.1 A g–1, a high rate capability of 452 mA h g–1 at 5 A g–1, and a long-term cycling stability (320 mA h g–1 at 2 A g–1 with 54.7% retention after 500 cycles) for the Na half-cell. Coupling with activated carbon (AC), our MoS2–SnS@g-C3N4/G||AC sodium-ion hybrid capacitor delivers high energy/power densities (193.1 W h kg–1/90 W kg–1 and 41.5 W h kg–1/18,000 W kg–1) and a stable cycle life in the potential range of 0–4.0 V.
Signal amplification in biological systems is achieved by cooperatively recruiting multiple copies of regulatory biomolecules. Nevertheless, the multiplexing capability of artificial fluorescent ...amplifiers is limited due to the size limit and lack of modularity. Here, we develop Cayley tree-like fractal DNA frameworks to topologically encode the fluorescence states for multiplexed detection of low-abundance targets. Taking advantage of the self-similar topology of Cayley tree, we use only 16 DNA strands to construct n-node (n = 53) structures of up to 5 megadalton. The high level of degeneracy allows encoding 36 colours with 7 nodes by site-specifically anchoring of distinct fluorophores onto a structure. The fractal topology minimises fluorescence crosstalk and allows quantitative decoding of quantized fluorescence states. We demonstrate a spectrum of rigid-yet-flexible super-multiplex structures for encoded fluorescence detection of single-molecule recognition events and multiplexed discrimination of living cells. Thus, the topological engineering approach enriches the toolbox for high-throughput cell imaging.
In this study, graphene oxide was synthesized, characterized and applied for cesium removal from aqueous solution. The effect of various parameters, including adsorbent dosage (0.05–0.2 g L−1), pH ...(3–9) and ionic strength (NaNO3 0.001–0.1 mo L−1) on adsorption capacity, as well as its adsorption kinetics, isotherms, thermodynamics and mechanism were investigated. The experimental results indicated that the adsorption of cesium (I) by the graphene oxide was an exothermic, pH- and ionic strength-dependent process. The pseudo second-order kinetic model and the Langmuir model fitted this process well, and the adsorption capacity was calculated to be 95.46 mg g−1. According to the analytical results of XRD, FTIR, and XPS, the adsorption mechanism for cesium ions should be attributed to the oxygen-containing functional groups of the graphene oxide.
•Graphene oxide (GO) was synthesized, characterized, and applied for cesium removal.•The effect of various parameters on adsorption capacity was examined.•Cs adsorption by GO was an exothermic, pH- and ionic strength-dependent process.•The adsorption of cesium was attributed to the O-containing functional groups.
Discrete memristors (DMs) have attracted increasing interest in recent years and can be applied in chaotic circuits and neuromorphic systems. To better enrich and enhance the kinetics and performance ...of DM maps, this article introduces two improved control methods to construct a series of DM maps with different network typologies by coupling DM seed maps. Some specific examples are demonstrated to back up these methods. Due to the effect and specific constructs of memristors, the new coupling DM maps will have infinite invariant points with higher dimensions, whose advantages of larger parameter space and expended chaotic ranges are evaluated by dynamic simulations. Besides, to investigate the application of the proposed methods, these new DM maps are implemented on the DSP platform, and the pseudorandom number generator is designed, as well as their high randomness is indicated by the strict test results.
Abstract
Objectives
Along with the development of the times and progress of the society, the total fertility rate (TFR) markedly changed in each country. Therefore, it is critical to describe the ...trend of TFR and explore its influencing factors. However, previous studies did not consider the time lag and cumulative effect in the associations between the influencing factors and TFR. Thus, our study aimed to analyze the associations from a new dimension.
Methods
The study was employed using national-level data from the World Bank and United Nations Development Programme. Distributed lag non-linear models with 5-year lag were used to examine the independent associations between the relevant factors and TFR.
Results
The cumulative exposure-TFR curves were inverted U-shaped for log gross domestic product (GDP) per capita and life expectancy at birth, while the cumulative exposure-response curves were approximately linear for female expected years of schooling and human development index (HDI). However, it is worth noting that in the developed regions, TFR increased slightly with the high level of GDP per capita, female expected years of schooling and HDI.
Conclusions
Nowadays, with the growth of GDP per capita, life expectancy at birth, female expected years of schooling and HDI, TFR are on a drastic downward trend in most regions. Besides, with the development of society, when levels of the factors continued to increase, TFR also showed a slight rebound. Therefore, governments, especially those in developing countries, should take measures to stimulate fertility and deal with a series of problems caused by declining TFR.
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