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Hydrogels are promising material for wound dressing and tissue engineering. However, owing to their low tissue adhesion in a moist environment and lack of flexibility, hydrogels are still not widely applied in movable parts, such as joints. Herein, we report a dual-crosslinked hydrogel adhesive using a dopamine-modified and acrylate-terminated crosslinker, tri(ethylene glycol) diacrylate-dopamine crosslinker (TDC). The covalent crosslinking was formed by photopolymerization between acrylic acid (AA) and TDC, and the noncovalent crosslinking was formed by intermolecular dopamine-dopamine and dopamine-AA interactions. Our resultant hydrogel demonstrated strong tissue adhesion in a moist environment (approximately 71 kPa) and high mechanical resilience (approximately 94%) with immediate recovery at a 200% strain rate. Moreover, it accelerated wound healing upon dressing the wound site properly. Our study provides the potential for advanced polymer synthesis by introducing a functional crosslinking agent.

Halide perovskites, fascinating memristive materials owing to mixed ionic-electronic conductivity, have been attracting great attention as artificial synapses recently. However, polycrystalline nature in thin film form and instability under ambient air hamper them to be implemented in demonstrating reliable neuromorphic devices. Here, we successfully fabricated vertically aligned 2D halide perovskite films (V-HPs) for active layers of artificial synapses, showing moisture stability for several months. Unlike random-oriented HPs, which exhibit negligible current hysteresis, the V-HPs possess multilevel analog memristive characteristics, programmable potentiation and depression with distinguished multi-states, long-short-term plasticity, paired-pulse facilitation, and even spike-timing-dependent plasticity. Furthermore, high classification accuracy is obtained with implementation in deep neural networks. These remarkable improvements are attributed to the vertically well-aligned lead iodide octahedra acting as the ion transport channel, confirmed by first-principles calculations. This study paves the way for understanding HPs nanophysics and demonstrating their potential utility in neuromorphic computing systems.

Bi catalysts supported on GaN nanowires/Si photocathode induce favorable activity toward CO2 reduction to HCOOH.

This study identifies efficient earthquake intensity measures (IMs) for seismic performances and fragility evaluations of the reactor containment building (RCB) in the advanced power reactor 1400 (APR1400) nuclear power plant (NPP). The computational model of RCB is constructed using the beam-truss model (BTM) for nonlinear analyses. A total of 90 ground motion records and 20 different IMs are employed for numerical analyses. A series of nonlinear time-history analyses are performed to monitor maximum floor displacements and accelerations of RCB. Then, probabilistic seismic demand models of RCB are developed for each IM. Statistical parameters including coefficient of determination (R2), dispersion (i.e. standard deviation), practicality, and proficiency are calculated to recognize strongly correlated IMs with the seismic performance of the NPP structure. The numerical results show that the optimal IMs are spectral acceleration, spectral velocity, spectral displacement at the fundamental period, acceleration spectrum intensity, effective peak acceleration, peak ground acceleration, A95, and sustained maximum acceleration. Moreover, weakly related IMs to the seismic performance of RCB are peak ground displacement, root-mean-square of displacement, specific energy density, root-mean-square of velocity, peak ground velocity, Housner intensity, velocity spectrum intensity, and sustained maximum velocity. Finally, a set of fragility curves of RCB are developed for optimal IMs.

Cross-linking is an essential element in enhancing polymers’ mechanical properties in adhesives, elastomers, and hydrogels. However, covalent cross-linking introduces a trade-off relationship betwe...

The impact of Si3N4 content on the hardness and microstructural developments of ZrB2-SiC material has been investigated thoroughly in the present investigation. Having prepared the raw materials in a jar mill, the ZrB2-SiC samples containing various amounts of Si3N4 were hot-pressed at 1850 °C. Furthermore, XRD, FESEM, and HRTEM were utilized to evaluate the microstructure of samples. The formation of in-situ h-BN was proved by the mentioned methods. Also, it was shown that the Vickers hardness of ZrB2-SiC increases up to 20 GPa in presence of 4.5 wt% Si3N4 which is 3 GPa more than the sample without Si3N4. Results show that the positive effect of increased relative density on hardness is more than the negative effect of h-BN soft phase formation.

An ultra-high temperature composite with superior mechanical characteristics was developed using zirconium diboride (ZrB2, 60% by volume), silicon carbide (SiC, 30% by volume), and tantalum carbide (TaC, 10% by volume), and its microstructure characteristics and mechanical properties were obtained experimentally by nanoindentation testing, X-ray diffraction, field emission scanning electron microscopy, X-ray fluorescence analysis, and X-ray photoelectron spectroscopy. Oxide contamination was eliminated, and the ceramic was densified to achieve a fully-dense ternary compound. To assess its performance in a typical real-world application, a finite element analysis was performed using the commercially available ABAQUS package for a one-bay one-story steel frame in which the prepared ceramic was used for the beam–column joint reinforcement end-plates; a good agreement was found with the results reported in the literature for comparable structures. The performance of a steel frame with a plate prepared from functionally graded materials located at the beam–column joint was then modeled in ABAQUS and subjected to the conditions recorded during a 1940 earthquake with a magnitude of 7.7. The results show that the utilized ceramic significantly enhanced the structural behavior of the reinforced concrete frame, confirming its potential utility in a wide range of industrial, structural, and medical applications.

The squat flanged reinforced concrete (RC) walls have been widely utilized in nuclear power plant and building structures. Nevertheless, the empirical equations in current design codes and published studies show a significant discrepancy in calculating the shear strength of the walls. The purpose of this study is to develop an effective machine learning model, namely artificial neural network (ANN), for predicting the shear strength of squat flanged RC walls. A total of 369 test results of squat flanged RC walls were collected from the literature and used to develop the ANN model. The results of the proposed model were compared with those of existing design codes and published studies. The comparisons emphasized that the developed ANN model in this paper can predict the shear capacity of squat flanged RC walls more accurately than the existing equations. Moreover, the effect of input parameters on the predicted shear capacity of the walls was sufficiently investigated. A predictive formula based on the ANN model, which can cover thirteen input parameters, was then proposed to compute the shear strength of the squat flanged walls. Additionally, an efficient graphical user interface (GUI) platform has been established for facilitating the practical design process of the squat flanged RC walls.

Abstract Dedications to achieve the highly efficient metal oxide semiconductor for the photoelectrochemical water splitting system have been persisted to utilize the TiO2 as the promising photoanode material. Herein, we report notable progress for nanostructured TiO2 photoanodes using facile sequential one-pot hydrothermal synthesis and annealing in hydrogen. A photocurrent density of 3.04 mA·cm−2 at 1.23 V vs. reversible hydrogen electrode was achieved in TiO2 nanorod arrays annealed in hydrogen ambient, which is approximately 4.25 times higher than that of pristine TiO2 annealed in ambient air. 79.2% of incident photon-to-current efficiency at 380 nm wavelength demonstrates the prominence of the material at the near-UV spectral range region and 100 h chronoamperometric test exhibits the stability of the photoanode. Detailed studies regarding crystallinity, bandgap, and elemental analysis provide the importance of the optimized annealing condition for the TiO2-based photoanodes. Water contact angle measurement displays the effect of hydrogen annealing on the hydrophilicity of the material. This study clearly demonstrates the marked improvement using the optimized hydrogen annealing, providing the promising methodologies for eco-friendly mass production of water splitting photoelectrodes. Graphical Abstract

Controlling phase transitions in correlated materials yields emergent functional properties, providing new aspects to future electronics and a fundamental understanding of condensed matter systems. With vanadium dioxide (VO

With the advent of the novel SARS-CoV-2, the entire world has been thrown into chaos with severe disruptions from a normal life. While the entire world was going chaotic, the researchers throughout the world were struggling to contribute to the best of their capabilities to advance the understanding of this new pandemic and fast track the development of novel therapeutics and vaccines. While various animal models have helped a lot to understand the basic physiology, nonhman primates have been promising and much more successful in modelling human diseases compared to other available clinical models. Here we describe the different aspects of modelling the SARS-CoV-2 infection in NHPs along with the associated methods used in NHP immunology.

2-Dimensional semiconductor SnS2 has emerged as one of the most prospective candidates for chemoresistive gas sensor applications due to its outstanding gas sensing performance. Herein, we propose the room temperature nitrogen dioxide (NO2) sensing of SnS2 nanoflowers (NFs) enabled by visible light activation. SnS2 NFs were successfully prepared by solvothermal synthesis with abundant edge sites. The high absorbance in the visible light region triggered the generation of charge carriers resulting in decreased resistance and enhanced gas sensing characteristics. Even under red light and green light with low photon energy, the room temperature NO2 sensing performance was improved. The highest NO2 sensing performance was accomplished under blue light, including the highest response, excellent selectivity towards NO2 and an extremely low detection limit. Moreover, the sensor exhibited reliable gas sensing performance in humid conditions and maintained its properties after long-term relaxation. Taking advantage of surface properties, optical properties and gas sensing properties, a light-activated SnS2 NF based gas sensor is anticipated to further develop SnS2 nanostructures for use in an electronic nose.

The purpose of this study is to identify efficient earthquake intensity measures (IMs) for evaluating the seismic vulnerability of integral abutment bridges. A total of 90 ground motion records and 20 typical IMs were employed for the numerical analyses. A series of nonlinear time-history analyses was performed on the bridges to observe the lateral displacement of the bridge piers. Statistical parameters such as the coefficient of determination, standard deviation, and correlation coefficient were calculated to identify the strongly correlated IMs with the seismic performance of the bridges. The numerical results show that the efficient IMs are spectral acceleration, spectral velocity, spectral displacement at the fundamental period, acceleration spectrum intensity, effective peak acceleration, peak ground acceleration, and A95. Moreover, a set of fragility curves of the bridges was developed with respect to the efficient IMs.

NiFe layered double hydroxides (LDH) on n-Si can be an expectable photoanode because of its advantages of earth-abundant materials, high photoelectrochemical properties, and wide solar spectrum. Ho...

As the BO6 octahedral structure in perovskite oxide is strongly linked with electronic behavior, it is actively studied for various fields such as metal–insulator transition, superconductivity, and...

BiVO4 has emerged as a promising photoanode for water oxidation. Technical barriers such as charge recombination and photocorrosion prevent its practical application. In the present work, a NiCo2O4...

Dedications to achieve the highly efficient metal oxide semiconductor for the photoelectrochemical water splitting system have been persisted to utilize the TiO

Formation of type II heterojunctions is a promising strategy to enhance the photoelectrochemical performance of water-splitting photoanodes, which has been tremendously studied. However, there have been few studies focusing on the formation of type II heterojunctions depending on the thickness of the overlayer. Here, enhanced photoelectrochemical activities of a Fe

α-Gallium oxide, with its large band gap energy, is a promising material for utilization in power devices. Sapphire, which has the same crystal structure as α-Ga

Direct consideration for both, the catalytically active species and the host materials provides highly efficient strategies for the architecture design of nanostructured catalysts. The conventional wet chemical methods have limitations in achieving such unique layer-by-layer design possessing one body framework with many catalyst parts. Herein, an innovative physical method is presented that allows the well-regulated architecture design for an array of functional nanocatalysts as exemplified by layer-by-layer adornment of Pd nanoparticles (NPs) on the highly arrayed silica nanorods. This spatially confined catalyst exhibits excellent efficiency for the hydrogenation of nitroarenes and widely deployed Suzuki cross-coupling reactions; their facile separation from the reaction mixtures is easily accomplished due to the monolithic structure. The generality of this method for the introduction of other metal source has also been demonstrated with Au NPs. This pioneering effort highlights the feasibility of physically controlled architecture design of nanostructured catalysts which may stimulate further studies in the general domain of the heterogeneous catalytic transformations.

Although lithium‐air batteries (LABs) are considered the promising alternative of existing lithium–ion batteries owing to their high energy density of 11 680 W h kg−1, their practical applications are limited by the technical issues, such as unstable solid electrolyte interface and dendrite formation from metal anode and insufficient bifunctional activities and durability from cathode catalyst. In order to resolve these bottlenecks, carbon nanostructures have been investigated owing to their high surface area, excellent electrical conductivity, electrochemical stability, and various modification chemistries. Herein, we comprehensively review a recent progress on the design of carbon nanostructures for their applications into metal hosts, protection layers, and bifunctional electrocatalysts of LABs. The correlation between the crystalline, electronic, porous, and chemical structures and the electrochemical properties of carbon nanomaterials are discussed depending on their classification and characteristics. Various chemical modifications, such as morphological control, hierarchical architecturing, heteroatom incorporation, and the formation of composites, for the improved electrochemical performances of anode and cathode will be also addressed. Furthermore, we deal with the perspectives for the ongoing obstruction and future guidance.

In the pandemic era, the development of high-performance indoor air quality monitoring sensors has become more critical than ever. NO

Highlights Two types of BiVO4/TiO2 heterostructure photoanodes comprising TiO2 nanorods (NRs) and TiO2 nanoflowers (NFs) with different (001) and (110) crystal facets, respectively, were designed.The higher photoactivity of BiVO4/TiO2 NFs than BiVO4/TiO2 NRs was attributed to the improvement of charge separation by the TiO2 NFs.The formation of type II band alignment between BiVO4 nanodots and TiO2 NFs expedited electron transport and reduced charge recombination. Supplementary Information The online version contains supplementary material available at 10.1007/s40820-022-00795-8., Although bismuth vanadate (BiVO4) has been promising as photoanode material for photoelectrochemical water splitting, its charge recombination issue by short charge diffusion length has led to various studies about heterostructure photoanodes. As a hole blocking layer of BiVO4, titanium dioxide (TiO2) has been considered unsuitable because of its relatively positive valence band edge and low electrical conductivity. Herein, a crystal facet engineering of TiO2 nanostructures is proposed to control band structures for the hole blocking layer of BiVO4 nanodots. We design two types of TiO2 nanostructures, which are nanorods (NRs) and nanoflowers (NFs) with different (001) and (110) crystal facets, respectively, and fabricate BiVO4/TiO2 heterostructure photoanodes. The BiVO4/TiO2 NFs showed 4.8 times higher photocurrent density than the BiVO4/TiO2 NRs. Transient decay time analysis and time-resolved photoluminescence reveal the enhancement is attributed to the reduced charge recombination, which is originated from the formation of type II band alignment between BiVO4 nanodots and TiO2 NFs. This work provides not only new insights into the interplay between crystal facets and band structures but also important steps for the design of highly efficient photoelectrodes. Supplementary Information The online version contains supplementary material available at 10.1007/s40820-022-00795-8.

For the last several years, indoor air quality monitoring has been a significant issue due to the increasing time portion of indoor human activities. Especially, the early detection of volatile organic compounds potentially harmful to the human body by the prolonged exposure is the primary concern for public human health, and such technology is imperatively desired. In this study, highly porous and periodic 3D TiO

Materials that can switch adhesive properties based on external stimuli are required in several industries for temporary bonding or transfer processes. Previously studied materials achieve this under restricted conditions (hydration, heat, and long switching times), and some materials have limitations related to reuse because of irreversible reactions or residue formation on substrates. Herein, a rapid photoresponsive switchable pressure-sensitive adhesive (PSA) fabricated using an acrylic polymer and an aliphatic monomer containing azobenzene is reported. The adhesion force of the proposed PSA can be switched by photoisomerizing the azobenzene moiety. The process induces the transition of surface energy and modulus of the PSA. Ultraviolet and visible light irradiation can switch the probe tack force from 200 to 4 kPa within 15-30 s. Adhesion switching is possible in a state wherein the PSA remains adhered to a substrate. Mini-LEDs are selectively transferred from the carrier PSA to a polydimethylsiloxane substrate following the process of partial adhesion switching of the PSA. The novel and switchable PSA, which exhibits a selective and repeatable adhesion switching property and high switching ratio when stimulated by light stimuli, may be potentially used to realize the mini-LED or micro-LED transfer processes.

Unlike traditional adhesives with a fixed adhesive force, switchable adhesives, which have an adhesive force that can be adjusted by external stimuli, are specifically designed to be released according to user demand, or to enable the transfer of fine electronic devices. Previously developed switchable adhesives have limitations such as a slow switching rate, narrow adhesion modulation range, or the lack of reusability. Thus, we fabricated switchable pressure-sensitive adhesives (PSAs) that can overcome these limitations. The adhesive force of each switchable PSA, which comprises an azobenzene-containing acrylic polymer and low molecular weight compounds, was designed to be activated/deactivated via ultraviolet (UV) and visible light irradiation. The adhesive force and UV intensity required for the switch were found to be dependent on the aliphatic chain length of the compound. The adhesive force of the SP-C10, i.e., a switchable PSA containing a azobenzene compound with an aliphatic chain of 10 hydrocarbons, increased to 3.5 N from nearly zero in response to only 30 s of low-level (25 mW cm−2) UV irradiation. Additionally, SP-C10 did not lose its adhesive force even after 30 cycles of repeated adhesion switching. The mechanism of adhesion switching influenced by UV intensity and the structure of low molecular weight azobenzene compounds are also reported.

Capacitors allow extremely fast charge and discharge operations, which is a challenge faced by recent metal-ion batteries despite having highly improved energy densities. Thus, combined type electric energy storage devices that can integrate high energy density and high power density with high potentials, can overcome the shortcomings of the current metal-ion batteries and capacitors. However, the limited capacities of cathode materials owing to the barren redox reactions are regarded as an obstacle for the development of future high-performance hybrid metal-ion capacitors. In this study, we demonstrate the redox-reaction-rendering effect of the much overlooked lanthanide elements when used as the cathode of lithium-ion capacitors using the mesoporous carbon (MC) as a matrix material. Consequently, these lanthanide elements can effectively enrich the redox reaction, thus improving the capacity of the matrix materials by more than two times. Typically, the Gd-elemental decoration of MC surprisingly enhances the capacity by almost two times as compared with the underacted MC. Furthermore, the La nanoparticles (NPs) decoration depicts the same behavior. Evident redox peaks were formed on the original rectangular cyclic voltammetry (CV) curves. This study provides the first example of embedding lanthanide elements on matrix materials to enrich the desired redox reactions for improving the electrochemical performances.

Goethite (α-FeOOH), thermodynamically the most stable phase among various iron (oxy)hydroxides, is getting attention as an oxygen evolution reaction (OER) catalyst due to its terrestrial abundance....

Seismic design practices and seismic response analyses of civil structures and nuclear power plants (NPPs) have conventionally used the peak ground acceleration (PGA) or spectral acceleration (Sa) as an intensity measure (IM) of an earthquake. However, there are many other earthquake IMs that were proposed by various researchers. The aim of this study is to investigate the correlation between seismic responses of NPP components and 23 earthquake IMs and identify the best IMs for correlating with damage of NPP structures. Particularly, low- and high-frequency ground motion records are separately accounted in correlation analyses. An advanced power reactor NPP in Korea, APR1400, is selected for numerical analyses where containment and auxiliary buildings are modeled using SAP2000. Floor displacements and accelerations are monitored for the non- and base-isolated NPP structures while shear deformations of the base isolator are additionally monitored for the base-isolated NPP. A series of Pearson's correlation coefficients are calculated to recognize the correlation between each of the 23 earthquake IMs and responses of NPP structures. The numerical results demonstrate that there is a significant difference in the correlation between earthquake IMs and seismic responses of non-isolated NPP structures considering low- and high-frequency ground motion groups. Meanwhile, a trivial discrepancy of the correlation is observed in the case of the base-isolated NPP subjected to the two groups of ground motions. Moreover, a selection of PGA or Sa for seismic response analyses of NPP structures in the high-frequency seismic regions may not be the best option. Additionally, a set of fragility curves are thereafter developed for the base-isolated NPP based on the shear deformation of lead rubber bearing (LRB) with respect to the strongly correlated IMs. The results reveal that the probability of damage to the structure is higher for low-frequency earthquakes compared with that of high-frequency ground motions. Keywords: Nuclear power plant, Earthquake intensity measure, High-frequency ground motion, Pearson's correlation coefficient, Seismic fragility curve

This study reports an effective method to enhance the performance of photoelectrochemical (PEC) solar water reduction. We design and prepare a SnO2@WS2 NF heterostructure on p-Si that has better vi...

Chemical manipulations of Prussian blues and Prussian blue analogues (PBAs) beyond first-row transition-metal cations have remained quite preliminary to this day. The presented report demonstrates ...

Aluminum ion batteries (AIBs) are considered, in principle, promising post-lithium-ion batteries, which are potential for using in grid-scale energy storage and electric vehicles, owing to the economic Al. The inflammable ionic liquid electrolyte endows stable plating and stripping of Al ions. A spotlighted research on cathode material has been preforming to obtain a high-performance cathode material that can match well with the prominent Al foil. However, one over-looked factor for the study of cathode materials is the cost and possibility of mass-production. With this key point in mind, we as the forerunner studied the CoS2/carbon nanotubes (CNTs) composite cathode material composed of low cost and commercialized CoS2 and multi-wall CNTs to promote the development of AIBs. Stable charge/discharge plateaus (at 1.2/0.9 V vs. AlCl4−/Al) during cycling test were obtained for the CoS2/CNTs product at a high current density of 1000 mA g−1, with an extremely high Coulombic efficiency of 98% and reasonable electrochemical capacities. This report is expected to contribute more contribution in the development of cathode materials for rechargeable AIBs.