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We present the synthesis and the characterization of a novel cellulose-based electroactive hydrogel obtained through a simple water-based process. Its swelling and electroactive properties are here studied especially in low salinity water solutions. By combining smart materials and three-dimensional printing technique, we assessed that hydrogels can be shaped as natural algae and their motion can be controlled with electric signals to mimic natural seaweed movements under the effect of water flow. This could constitute a first step toward the development of hybrid habitats where artificial smart algae could cohabit with real living organisms or microorganisms.
Several structure–property relationships are reported in large-area MoS2 thin films to understand the effect of sulfur vacancies along with complementary first-principles calculations. X-ray diffraction and reflectivity measurements demonstrated that sputtered MoS2 followed by a high-temperature sulfurization produced sharp film–substrate interface along with high crystalline order. Spectroscopic and transport measurements showed that removal of sulfur vacancies promoted A–B excitons, strong in-plane Raman modes, a sharp increase in dc resistivity, and strong photo-conducting behavior. We have clearly demonstrated that a hybrid method using magnetron sputtering can provide high-quality few-layer transition metal dichalcogenide films.
N-(3-Carboxypropyl) triphenylphosphonium bromide chitosan (TPPB-CS) was synthesized and characterized by FTIR, 1H NMR spectrometer, and Zeta potential. TPPB-CS showed a selectivity-toxicity among cancer cell lines (MG-63 and HepG2 cells) and mouse embryonic fibroblast cells (NIH3T3 cells). A significant effect on inhibiting cell migration in HepG2 cells was observed in vitro, and TPPB-CS could effectively inhibit tumor growth in H22-bearing mice in vivo. Furthermore, the distribution of cell cycle, the level of reactive oxygen species (ROS), mitochondrial transmembrane potential (∆ψm), the expression of tumor necrosis factor α (TNF-α), and vascular endothelial growth factor (VEGF) were examined to investigate the antitumor mechanism of TPPB-CS. The results suggested that the antitumor activity of TPPB-CS may be attributed to delay the cell cycle in S phase, alter the ROS and ∆ψm level, as well as regulate the TNF-α and VEGF secretion. TPPB-CS can become a promising anticancer drug for clinical therapy.
Ti–Al alloys are established as promising candidates for aerospace applications due to their lightweight, good elevated temperature strength, and decent corrosion resistance. In this study, a Ti–51Al (at.%) alloy is fabricated by spray deposition. The effects of temperature and strain rate on the deformation behavior of the spray-deposited Ti–Al alloy are investigated. The microstructural evolution of the Ti–Al alloy with different deformation temperatures is discussed in detail. A strain-dependent constitutive equation was proposed to predict the flow stresses at the elevated temperatures for the spray-deposited Ti–Al alloy. The microstructure of the as-deposited Ti–51Al alloy exhibits a α2/γ lamellar-structure with average size 25 ± 2 μm, due to the high cooling rate observed during solidification. The lamellar structure is embedded on a γ matrix. The amount of the α2/γ lamellar-structure reduces gradually with increasing the hot deformation temperature. After hot isostatic pressing at 1523 K, the microstructure is mainly comprised of the γ matrix.
In this paper, Sm3+-doped silicate glasses containing AgNO3 were obtained by the common melting quenching method. Influence of AgNO3 concentration on the absorption and emission characteristics of Sm3+ were systematically investigated. With the increase of AgNO3 content from 0 to 3.0 wt%, the ultraviolet region absorption edge shows a slight blue-shift from 275 to 260 nm. Exciting by 255 nm, the visible emission intensity of Sm3+-doped silicate glass containing 0.5 wt% AgNO3 was about 31 times stronger than that of Sm3+ singly doped silicate glass. Fluorescence decay curves for the visible emission followed double exponential decay. Two fluorescence lifetimes were obtained, one was about 7–20 μs which was comparable with the lifetimes of 350 nm emission which derived from Ag+, another was about 2 ms which was comparable with that of the visible emission from Sm3+ excited by 401 nm. Thus, the significant enhancement visible emission of Sm3+ excited by 255 nm can be ascribed to the energy transfer from Ag+ to Sm3+.
The powder thixoforming method was used to fabricate 10 vol% silicon carbide particle (SiCp) reinforced 6061 Al matrix composites with high mechanical performances successfully. Here, we demonstrated with proof that proper solution treatment could not only enhance tensile strength of the composite: its ultimate tensile strength and yield strength increased from 230 to 128 MPa in the as-fabricated state to 275 and 212 MPa solutionized at 808 K for 6 h but also improve composite’s tensile elongation significantly with an increment of 161.5% from 2.6% to 6.8%. Corresponding toughening mechanisms are mainly investigated from the perspective of both microstructure examination and total strain to failure calculation through a modified model. The theoretical predictions are in reasonably good agreement with the experimental data. This work may provide a practical way to alleviate the inverse strength–ductility relationship of particulate reinforced metal matrix composites and provide reference for the SF calculation of similar composites subjected to solution treatment.
It has been reported that the optimal properties of materials are usually not linear to the configuration entropy of materials; in another word, the high-entropy alloys may not have the best properties among all the alloys, including medium-entropy alloys, thus all of these alloys can be universally named as entropic alloys. For entropic alloys, the design, discovery, and optimization of new materials are more complicated than conventional materials. A technique of high-throughput processing is urgently needed to improve the efficiency. In this paper, a combined method by using multitarget deposition has been proposed for parallel preparation of high-entropy to medium-entropy alloys. Films with compositional gradient were constructed in a pseudo-ternary Ti–Al–(Cr, Fe, Ni) system in this study. To facilitate the characterization of the material library, it has been divided into 144 independent units with an area of 1 cm2 and the maximum value of compositional gradient reaches ∼13 at.%/cm. The material library exhibits a high coverage of composition, and the range of element content varies from 3.3 to 89.2 at.% on average. The stability and homogeneity of the material library were analyzed from phase structure and microtopography. Preliminary screening of the phase structure and properties were performed. The phases are mainly composed of amorphous phase and body-centered cubic phase. Hardness changes nonlinearly with compositions. The material library synthesized in this study is expected to provide an effective platform for high-throughput screening of multicomponent materials.
This article focuses on the finite element modeling of toroidal microinductors, employing first-of-its-kind nanocomposite magnetic core material and superparamagnetic iron nanoparticles covalently cross-linked in an epoxy network. Energy loss mechanisms in existing inductor core materials are covered as well as discussions on how this novel core material eliminates them providing a path toward realizing these low form factor devices. Designs for both a 2 μH output and a 500 nH input microinductor are created via the model for a high-performance buck converter. Both modeled inductors have 50 wire turns, less than 1 cm3 form factors, less than 1 Ω AC resistance, and quality factors, Q’s, of 27 at 1 MHz. In addition, the output microinductor is calculated to have an average output power of 7 W and a power density of 3.9 kW/in3 by modeling with the 1st generation iron nanocomposite core material.
This article reviews the semiconductor and metal-based nanohybrid-sensitized photoelectrochemical (PEC) cells for hydrogen generation from water. The nanoscale hybridization of sensitizers in the photoanode can enhance light harvesting, interfacial charge transfer, charge separation, and induce a catalytic effect in dependence on the kind of the components and interfacial junction state. Subsequent to the introduction, second and third sections present the basic structure and design of the nanohybrid-sensitized PEC cell. Fourth section deals with the effect of the interfacial bond between quantum dots and TiO2 on the electron injection process. Fifth section mainly describes the formation of heteroepitaxial junction between the components of nanohybrids. In the sixth section, the state-of-the-art nanohybrid-sensitized PEC cells are treated with a particular emphasis placed on the interface state.
The microstructure of In(As,Bi)/GaAs heterostructures grown by low-temperature molecular beam epitaxy with special attention to the interfaces was studied by scanning/transmission electron microscopy, energy dispersive X-ray microanalysis, and X-ray diffraction and reflectivity. Two samples grown at similar conditions with and without the presence of the Bi-contained layer, formed at 350 °C, are considered. These samples were jointly analyzed to clarify Bi influence on the crystal structure. Two types of QD-like clusters at the GaAs/In(As,Bi) interface were found. The first type exhibited a zinc blend crystal structure, which is typical for A3B5 semiconductors. The second type adopted a tetragonal PbO crystal structure and was found in different orientations. The joint analysis by electron microscopy and X-ray methods demonstrated that the incorporation of Bi atoms into the InAs layer leads to the strain relaxation at the interface in the growth direction. According to electron microscopy data, this strain release is more pronounced around the clusters of the second type.
Herein, we show that scanning probe microscopy (SPM) is an effective tool permitting to disclose the nature of the colossal dielectric permittivity characteristic of CaCu3Ti4O12 (CCTO) compound. SPM data confirm the existence of micro- and nanoscale barrier layer capacitance mechanisms which simultaneously contribute to the electrical conductivity of the material. The former mechanism is associated with the potential grain-to-grain barriers. The latter mechanism involves the barriers created by intragrain structural defects. The results of the SPM study shed new light on the origin of the colossal dielectric constant in CCTO.
The inefficiencies of the current pipeline from discovery to clinical approval of drugs demand a surrogate method to indicate adverse drug reactions, e.g. liver damage. Organ-on-chip (OOC) models would be an ideal, rapid, and human-specific alternate, which would render animal testing obsolete. The ground-breaking ability of OOCs and Multi-OOC constructs is the accurate simulation of the in vivo conditions of human organs leading to precise drug screens for cytotoxicity and/or drug efficacy at a faster pace and lesser cost. Here we discuss the innovation, architecture, and the progress of OOCs towards human body-on-a-chip.
The structure of polymer networks in hydrogels determines the properties. In this study, we investigated the structure of a charge-balanced polyampholyte, poly(4-vinylbenzenesulfonate-co-[3-(methacryloylamino) propyl] trimethylammonium chloride). From as-prepared samples, nanoscale globules were visualized in polyampholyte hydrogels for the first time. The impact of dialyses processes on polymer structures were also studied. In deionized water, salt ions are leached out, thus polymer chains undergo zipping process to form cellular structure with micrometer-thick polymer walls that allow mechanical toughness to the hydrogel. Samples dialyzed in 6 M potassium hydroxide solution did not show such cellular structure, as in the case of as-prepared samples.
Lateral memristors consisting of planar Ag electrodes (with sub-micrometer separation) supported on thin films of amorphous zinc-tin-oxide have been characterized. After an initial filament-forming process, each device exhibited volatile, resistive switching. In the low resistance state, the transport mechanism and conductance depended on prior activity and on the imposed current limit, mimicking biologic synaptic plasticity. Microscopic observations performed on each device revealed nanoscale filaments between the electrodes. These filaments were subject to Rayleigh instability and exhibited relaxation times determined by their effective radii. The relaxation times and on:off resistance ratios suggest suitability for threshold switching selector devices.
A novel process for Boron doping of ultrananocrystalline diamond (UNCD) films, using thermal diffusion, is described. Hall measurements show an increase in carrier concentration from 1013 to 1020 cm−3. Ultraviolet Photoelectron Spectroscopy and x-ray Photoelectron Spectroscopy show a band gap of 4.4 eV, a work function of 5.1 eV and a Fermi level at 2.0 eV above the valence band. Boron atoms distribution through UNCD films, was measured by Secondary Ion Mass Spectrometry, revealing Boron atoms diffusivity of about 10−14 cm2/s. Raman spectroscopy and x-ray Diffraction analysis revealed that UNCD films did not suffer graphitization nor structural damage during annealing.
Efficient applications of magnetic cores in sensing and power electronics require low-loss and versatile soft magnetic materials, with excellent response on a wide range of frequencies. This objective is traditionally pursued with ferrite and Permalloy tape cores, available under a variety of properties. Comparable and even superior soft magnetic behavior can, however, be obtained with amorphous and nanocrystalline alloys, with the latter, in particular, combining flexible response to thermal treatments with high magnetic saturation. Broadband precise magnetic characterization of these materials, crucial to their use as inductive cores, is fully appreciated when associated with assessment by physical modeling. Comprehensive measuring approach and significant results obtained in sintered soft ferrites and nanocrystalline ribbons up to 1 GHz are highlighted in this paper. We show how broadband loss and permeability behaviors can be quantitatively interpreted in the framework of the loss separation concept, applied to eddy current and spin damping dissipation mechanisms.