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This paper describes the fabrication of biopolymer foams from aqueous solutions of carboxymethyl cellulose (CMC), as well as effective methods for stabilizing CMC foams in aqueous environments so as to prevent their conversion to gels that results from pore collapse. CMC foams were produced easily by lyophilization of aqueous solutions of high molecular weight CMC, but the considerable hydrophilicity of this anionic polyelectrolyte led to rapid pore collapse and gelation of the material upon its contact with liquid water. However, the porous structure of the CMC foam was stabilized in the presence of aqueous solutions of CaCl2. Mechanical measurements showed the foams to be stiffer in the presence of higher salt concentrations. In addition, CMC foams crosslinked with poly(acrylic acid) (PAA), via the residual hydroxyl groups on the CMC scaffold, were stable in liquid water. When covalent crosslinking was combined with the presence of CaCl2, and/or cellulose additives, the resultant CMC foams exhibited excellent aqueous stability for months or longer and withstood multiple compression cycles without loss of mechanical performance (i.e., by maintaining their porous foam structure). These hydrophilic foams absorbed many times their own weight of water (> 30 g of liquid water per gram of foam) and were amenable to ion exchange, absorption/desorption of organic substances and heavy metals, and water uptake at levels that make them attractive materials for applications in water recovery. [ABSTRACT FROM AUTHOR]

The mechanism of microstructure evolution during rapid solidification and the proactive regulation of phase constitution to optimize the micromechanical properties of multicomponent alloys have been the focus of research in recent years. In this paper, the evolution of microstructural growth kinetics and the formation of amorphous phase in CoCrFeNiZr0.5 alloy were achieved by melt spinning technique and electrostatic levitation coupled melt quenching. According to the theory of transient nucleation, the nucleation incubation time of Laves, FCC, Fe23Zr6 and BCC phases with undercooling during rapid solidification of the alloy was calculated. And based on this, the mechanism of phase transition in the process of regular eutectic → anomalous eutectic → nanocrystalline → amorphous composite → complete amorphous structure was discussed and explained. The growth behavior of primary and eutectic phases solidified at different undercoolings was investigated. Combined with melt quenching, the alloy melts were quenched in the superheated state, liquidus, undercooled state and recalescence process. Multiple microstructures, including amorphous structure, amorphous plus nano-eutectic, gradient nano-eutectic and composite structure of primary Laves phase, along with primary eutectic plus secondary quenched eutectic structures were obtained, respectively. Moreover, the shear band and free volume theory were applied to explain the deformation behavior and the discrepant mechanical performance between amorphous composites and amorphous structures. The formation of quenched nano-eutectic and amorphous structure not only improves the hardness of the alloy, but also enhances the fracture toughness. [ABSTRACT FROM AUTHOR]

In this paper, the waterborne aluminum pigments with intelligent anticorrosion properties and bright colors were prepared by encapsulating multifunctional composite layers, which were composed of zeolitic imidazole framework (ZIF) and silica. With the results of the micropores and microcracks generated in the silica layer, the penetration of acidic corrosion into the inner layer caused the ZIF layer to release the linker as the corrosion inhibitor and construct a new barrier on the metal surface due to the high corrosion inhibitor content in ZIF. After the pH response, the highest impedance of the aluminum pigments was up to 4.35 × 105 Ω cm2. The aluminum pigments with the multifunctional composite layers (Al@ZIF-B@SiO2) could maintain stability at pH = 1. Meanwhile, the excellent adsorption and porosity of ZIF were applied to sorb the dye, which endowed the aluminum pigments with bright colors. The functional composite layers on the aluminum pigments eliminated the hydrogen emission, which proved the excellent chemical stability of the prepared samples. The sensitive pH responsiveness of Al@ZIF-B@SiO2 was also testified. [ABSTRACT FROM AUTHOR]

The commendable growth of portable and wearable electronics has taken the energy harvesting sector to new heights. Using the idea of nanogenerators for ambient nano-energy harvesting started with the emergence of the piezoelectric energy harvester reported in 2006. Three diverse types of nano-energy harvesters have developed: piezoelectric nanogenerators, triboelectric nanogenerators for harvesting mechanical energy, and pyroelectric nanogenerators for ambient heat energy harvesting. However, the efficiency of these nano-energy harvesters is limited to converting individual energy sources into electrical energy. Since technology is improving day by day, the requirement for efficient, sustainable hybrid energy harvesters is of great interest. Hybrid nanogenerators can be developed by combining two or more nanogenerators mentioned above. In this regard, hybrid tribo-piezoelectric nanogenerators, hybrid tribo-pyroelectric nanogenerators, and hybrid tribo-piezo-pyroelectric nanogenerators exist. The hybrid nanogenerators will have the essential characteristics of the individual nanogenerator with which it is developed, and a positive synergism can enhance the efficacy. This paper reviews the recent advancements in biocompatible energy harvesting materials that are efficient enough to be used as active layers in the tribo-, piezo-, and hybrid tribo-piezoelectric energy harvesters for wearable and biomedical applications. The article focuses on the properties, synthesis, development of materials, usage, hybrid tribo-piezoelectric energy harvesters, and their efficiency, which are made up of these materials, their applications, and finally, the conclusions and future perspectives of these materials. [ABSTRACT FROM AUTHOR]

In this paper, the bimetallic cathode material of cobalt vanadium organic framework (Bimetallic organic framework) is fabricated by facile hydrothermal method and heat treatment. The hollow spheric and porous surface containing tailored morphology of bimetallic MOF composite plays a pivotal role in energy storage application. That is efficaciously inherited from the base cobalt MOF imidazolate template. The electrochemical analysis delineated that the vanadium interpolated ZIF-67 MOF composite unveiled an augmented super capacitive performance. The as-obtained specific capacitance is 549 F/g at a 2 mV/s scan rate, and 349 F/g at 3 mA/cm2 applied current value. Furthermore, exceptional capacity retention of over 89% and 95% coulombic efficiency was obtained for the fabricated cathode material even after 5000 cycles. Combining biowaste-derived activated carbon with a Bimetallic Organic Framework, the asymmetric device of supercapacitor storage is fabricated. That device works on 0–1.4 V windows. The accomplished galvanometric capacitance is 151 F/g in the 4 mA current with the maximum specific energy of 42.6 Wh/kg and the specific power of 1399 W/kg and exhibited promising stability over 10000 cycles. These attained results affirm its proficient application as cathode material of supercapacitor devices. Write up The porous hollow-spheric Bimetallic organic framework and biowaste derive APCs are assembled in an asymmetric solid-state supercapacitor device that delineates the real-time application by analyzing it with an LED glowing circuit about a reasonable time that can replicate the feasibility of a real-time portable energy storage device. [ABSTRACT FROM AUTHOR]

The effects of supersonic particle bombardment (SFPB) on the microstructure, microhardness and wear property of Ti6Al4V alloy prepared by laser metal deposition (LMD) were investigated in this paper. The electrochemical corrosion behaviors of the LMDed Ti6Al4V alloy samples before and after SFPB treatment in 3.5% NaCl solution were measured. The results showed that a gradient severe deformation layer of ~ 350 μm thickness was formed with refined equiaxed grains oriented in various directions on the surface of LMDed Ti6Al4V alloy after SFPB treatment. The microhardness of the deformation layer was significantly increased due to the plastic deformation, grain refinement, dislocations and deformation twins increment. After SFPB treatment, the LMDed Ti6Al4V exhibited higher wear resistance which is about 55.6% decrease in wear loss than that of the untreated sample. Moreover, the corrosion resistance and corrosion rate of the SFPB-treated samples in 3.5% NaCl solution improved due to the finer hexagonal grains and high density of grain boundary in the severe deformation layer. [ABSTRACT FROM AUTHOR]

In this paper, we have proved the possibility of improving the emissive properties of cerium, Ce3+, activated yttrium aluminium garnet (YAG:Ce) phosphor both by internally modifying the lattice parameters as a result of adding a codopant and by external silanization of the phosphor particle's surface. The addition of codopant in the form of gadolinium, Gd3+, ions was performed using the method of concomitant precipitation of metal cations. The silanization of phosphor was achieved by activating the surface and cross-linking of the (3-aminopropyl) triethoxysilane molecules. By FTIR spectroscopy and X-ray diffraction, we have assessed the influence of internal and external modifications on the structure of phosphor. At the same time, the optical properties using fluorescence spectroscopy were evaluated. The analysis of modified phosphor samples confirmed the improvement of the emissive properties of YAG:Ce and the possibility of manufacturing the white light-emitting devices with a high-efficiency degree as a result of the bathochromic shift, increasing the emission intensity and of the quantum yield. By linking organic compounds with amine terminal groups at YAG:Ce surface, it creates the premises for covalently linking biomolecules, expanding the range of applicability of these fluorescent materials. [ABSTRACT FROM AUTHOR]

Molybdenum–tungsten single-crystal system is a key component in thermionic energy converters which transform heat directly into electrical energy. In this paper, the thermal stability of the molybdenum–tungsten single-crystal system was studied after exposure at 1873 K for 5000 h. The microstructure was investigated by the coupling of scanning X-ray Laue diffraction and electron microscopy techniques. After thermal exposure, the interface between the tungsten layer and molybdenum substrate was transformed into a wavy morphology. Moreover, recrystallization phenomenon was only observed in the tungsten layer. The large difference in diffusivity between tungsten and molybdenum caused the formation of wavy interface. The recrystallization processing in the tungsten layer was related to the internal stress generated during the high-temperature exposure. This study is instructive for the lifetime prediction and developing next-generation tungsten emitters for the thermionic energy converter application. [ABSTRACT FROM AUTHOR]

Lithium–sulfur (Li–S) batteries, as a research hotspot, are expected to address the need for energy storage systems with high energy density. However, the slow reaction kinetics of polysulfides due to the loss of electrical contact of soluble polysulfides and further shuttle effect hinder the further progression of Li–S batteries. This paper reviews the recent efficient approach to remedy the above issues: active site construction in the electrode materials or separators. The active site construction includes the increasing surface area, inducing molecular and single-atom catalysts, inducing heteroatomic doping, vacancies, or functional group. The high specific surface area can provide more sites for loading sulfur and also the more active sites for adsorption. Many porous materials are designed to provide more transfer paths for ions. Molecular and single-atom catalysts use some catalysts such as Fe–N–C or single metal atoms in various matrixes, representing the high catalytic activity. Defects can improve the electronic conductivity to quicken lithium ions diffusion in electrode materials, but also render more active sites to enhance catalytic activity and adsorption of electrode materials, accelerating the conversion of long-chain polysulfides to the next short-chain polysulfides and final products Li2S2/Li2S. The common active site construction and characterization methods of diversiform materials, for example, carbon materials, metal oxides, metal sulfides, and some other metal-free materials, are reviewed in this paper. [ABSTRACT FROM AUTHOR]

Based on density functional theory, this paper uses first-principles methods to study the stability, electronic properties, anisotropy, thermodynamic properties, and optical properties of compound MB2 (M = V, Nb, Zr). The enthalpy of formation indicates that the compound MB2 is energy stable. Studying its electronic properties, it is concluded that the compound MB2 (M = V, Nb, Zr) has metallic properties from the band structure and density of states diagram. The analysis of the differential charge density shows that the binding force between B–M and M–M atoms is greater than that of B–B. The results of elastic performance research show that VB2, NbB2, and ZrB2 exhibit brittleness and are brittle materials. Moreover, VB2, NbB2, and ZrB2 also meet the mechanical stability standards. Research shows that the anisotropy of MB2 is: NbB2 > VB2 > ZrB2.The quasi-harmonic Debye model is used to study the thermodynamic properties of compound MB2 (M = V, Nb, Zr). We analyzed the change curve of heat capacity, volume, thermal expansion coefficient, and Debye temperature at 0–1600 K and 0–100GPa. According to the analysis of thermodynamic properties, MB2 also satisfies the thermal stability condition. Finally, this paper studies the absorption and reflection of light by MB2. It is found that absorption and reflection are relatively strong in the ultraviolet region. [ABSTRACT FROM AUTHOR]

In this paper, the chemical composition of 7Mo-alloyed super austenitic stainless steel was optimized and the principle of composition designing of Fe-24Cr-(22-x)Ni-7Mo-xCo (x = 0, 2, 4) alloys was discussed. Thermodynamic calculation, as well as microstructure observation, was carried out to investigate the precipitation behavior of Fe-24Cr-(22-x)Ni-7Mo-xCo alloys aged at 700–1100 °C. The results demonstrated that none of second phase was detected at 700 °C aging and at least three different types of precipitates, σ phase, χ phase and M23C6 were identified after aging at 800–1100 °C for 2 h. At all aging temperature, the intermetallic σ was determined as the dominant second phase. For alloys of 22Ni, 20Ni2Co and 18Ni4Co, the area fraction of precipitates increased first and then decreased with temperature increasing from 700 to 1100 °C. The 1000 °C was determined as the most sensitive temperature for this alloy. Furthermore, the area fractions of second phase of 20Ni2Co (x = 2) at all temperatures were lower than that of 22Ni (x = 0) and 18Ni4Co (x = 4). In addition, the characteristics of cellular precipitates growing have been disclosed in this paper. Compared with nickel-based alloy, the addition of cobalt did not affect the misfit between σ phase and austenite matrix, which is probably due to the high content of nitrogen in Fe-24Cr-(22-x)Ni-7Mo-xCo alloys. [ABSTRACT FROM AUTHOR]

To find a new type of sensing material with high sensitivity to acetone gas, in this paper, a first-principles method based on density functional theory was used to study the gas-sensing mechanism of perovskite-type ZnSnO3 to acetone. A hydrothermal method was used to prepare perovskite-type ZnSnO3, and perform a gas sensitivity test. Calculated results demonstrate that acetone molecules interacted strongly with the ZnSnO3(001) surface with pre-adsorbed O2− and O−, accompanied by charge transfer that can change the resistance of the material. This phenomenon provides the basis for using ZnSnO3 as an acetone gas-sensitive sensing material. The experimental results showed that the perovskite-type ZnSnO3 has a sheet structure with micro-holes on the surface, which can promote responsivity to acetone gas. The gas sensitivity test indicated the optimal operating temperature is 350 °C, the response/recovery time is 4 s/27 s. The sensitivities of the synthesized ZnSnO3 nanosheet that in this paper to 100 ppm and 10 ppm acetone gas are 125.444 and 8.37, respectively. In the five-week stability and repeatability test, the sensitivity to 10/100 ppm acetone of sheet-like ZnSnO3 sensor could still maintain at 89.64% and 94.74% of the first test result. This study provides theoretical guidance for the development of acetone gas sensors. [ABSTRACT FROM AUTHOR]

All-inorganic Cs2AgBiBr6 film is one of most promising materials in the perovskite family for long-term daily life photodetection applications, due to its fairly nice stability and lead-free nontoxic property. However, high annealing temperature (> 250 °C) process is widely used and low temperature synthesis of high-quality Cs2AgBiBr6 is still a big challenge, which limits the development toward flexible device. Herein, we developed a Mn doping solution route for Cs2AgBiBr6 perovskite which is the first reported element doping process that can effectively improve the film quality under low annealing temperature. The corresponding flexible photodetectors exhibit favorable self-power characteristics and satisfying photoelectric performance with high detectivity of > 1010 Jones, μs level response speed and large LDR over 110 dB. Such good performance can be maintained even at 120 °C fabrication process. The material properties, device performances and doping mechanism are systematically discussed in the paper. To our knowledge, this is one of the lowest temperature fabrication processes for high performance flexible Cs2AgBiBr6 devices. Our results suggest a feasible method and indicate the promising application of Cs2AgBiBr6 films for flexible photovoltaic devices. [ABSTRACT FROM AUTHOR]

In this paper, we propose a new way of making pure zinc tungstate (ZnWO4) nanocrystals through thermal plasma processing. Initially, we prepared amorphous powders by the coprecipitation method at room temperature and then, these powders were processed at different temperatures between 400 and 600 °C for 1 h by the thermal plasma technique. Structural analyses with characterizations by X-ray diffraction, Rietveld refinement data, micro-Raman, and Fourier transform-infrared spectroscopies indicate a transition from the amorphous phase (coprecipitated) to intermediate (W18O49 and ZnO phases) and desired ZnWO4 phase between 400 and 550 °C for 1 h. These characterizations confirmed the best effect of thermal plasma at 600 °C for 1 h to obtain single-phase ZnWO4 pristine with a wolframite-type monoclinic structure and typical vibrational modes. The ultravioleta-visible diffuse reflectance spectroscopy revealed a decrease in optical band energy values from 3.97 to 3.20 eV. Field emission scanning electron microscopy showed clear images of a considerable morphological modification of small spherical and irregular particles referring to the W18O49 and ZnO phases to a growth more homogeneous of rod-like ZnWO4 nanocrystals related to pristine phase with size from 132 to 155 nm. The sonocatalytic, photocatalytic, and sonophotocatalytic (SPC) properties for degradation of Rhodamine 6G (Rh6G) were investigated. The better SPC degradation rate at Rh6G dye in 80 min was performed with ZnWO4 nanocrystals processed at 600 °C. Finally, the radical scavengers assays indicated that hydroxyl (·OH) and superoxide ( O 2 · - ) radicals are the main ones responsible for the chemical reactions to Rh6G dye degradation. A new method of processing using thermal plasma was employed to make pristine ZnWO4 nanocrystals at 600 ºC for 1 h and their structural evolution, shape, photocatalytic, sonocatalytic, and sonophotocatalytic properties were investigated in detail. [ABSTRACT FROM AUTHOR]

Although B4C-based composites exhibit excellent comprehensive mechanical properties, the microscopic strength and toughness mechanism are still unclear. In this paper, the B4C–ZrB2–SiC composites with excellent mechanical properties were prepared at 1900 °C and 45 MPa for 1 h using vacuum hot pressing assisted by reaction sintering (VHP-RS). They included the relative density of 95.97 ~ 99.25%, the Vickers hardness of 36.76 ~ 37.26 GPa, the flexural strength of 807.34 ~ 882.24 MPa, and the fracture toughness of 5.18 ~ 6.75 MPa·m1/2. Then, the strengthening and toughening mechanism of dislocation were systematically investigated by HRTEM, IFFT, EDS-mapping, etc. The classical "bow-out" process of dislocation line and lamellar dislocation ring was observed as the feature of the Orowan strengthening. Dislocation piling up at grain boundary inhibits the initiation of dislocation sources. The dislocations near twin boundaries are blocked by twin boundaries and stacking faults. Grain boundaries containing segregated silicon, boron and zirconium are easy to gather around the dislocation to nail the dislocation. The above reasons make the composites have excellent flexural strength. Meanwhile, dislocation slips in SiC and ZrB2 grains promote plastic deformation and improve the fracture toughness of the composites. The changes of the a relative density, Vickers hardness, and b flexural strength, fracture toughness of the B4C–ZrB2–SiC composites with the increase of component content. [ABSTRACT FROM AUTHOR]

Calcium phosphates are extensively used biomaterials for repairing bone tissue due to their osteoconduction and osteoinduction properties. Hydroxyapatite (HAp) is a type of calcium phosphate that has gained the attention of researchers because of its high crystallinity, superior corrosion resistance, and good mechanical and biological properties. This makes it ideal for use in dental and orthopaedic applications. Natural HAp particles present in physiological tissues have plate-like or rod-like morphology in the nanometre range, while synthetic HAp particles exhibit an irregular morphology and are in the micron range. The usage of surfactants as templates during the synthesis has become a successful strategy to regulate the morphology and size of the HAp particles to closely resemble the natural HAp. In this article, the authors have reviewed the effects of various chemical surfactants (such as cationic, anionic, zwitterionic, and non-ionic), biosurfactants (or biomolecules extracted from different parts of plants such as roots and leaves), and bio-wastes on the structural (morphology, size, and shape) and biological (bioactivity and biocompatibility) properties of the HAp particles synthesized through various methods. The nucleation and growth mechanisms of HAp particles in the presence of various surfactants through different methods are discussed. Even though there has been significant research on surfactant-assisted HAp particles, the detailed mechanisms behind the changes in the biological properties with the addition of surfactant are poorly understood. This review paper also highlights the current progress in the synthesis and characterization of surfactant-assisted HAp and provides guidance for future research on this topic. [ABSTRACT FROM AUTHOR]

The effect of Ni in Ag–Cu filler on the wetting and brazing characterization of stainless steel was studied by means of wetting test and brazing test under high vacuum condition. The wettability of filler metal and the joint strength were improved after adding Ni in Ag–Cu filler. The filler penetrates into stainless steel and the topmost steel grains separate from the substrate, exposing the metal surface without oxide film after adding Ni, which leads to the reduction in contact angle. The interdiffusion between FM and SS is enhanced after adding Ni, which leads to further reduction in contact angle. At wetting temperature, large amount of Ni in liquid enriched at solid–liquid interface, increasing the Cu content in liquid near the interface to form Cu-rich liquid, which caused the penetration of liquid filler. Cu first penetrates into steel grain boundary, which provides a path for Ni diffusion into stainless steel. After the oxide film was removed, a large number of Ni directly diffused into stainless steel to form (γ-Fe, Ni) layer on stainless steel surface. Cu in liquid can directly diffuse into (γ-Fe, Ni). Stainless steel can dissolve in Cu-rich liquid with high Ni content. In the absence of Ni, FM/SS interface is the weakest location of the joint. After adding Ni in filler, the formation of Cu solid solution at FM/SS interface and the enhancement of interdiffusion between FM and SS strengthen the FM/SS interface, leading to the increase in joint strength. The results in this paper suggest Ni is beneficial for brazing stainless steel by Ag–Cu alloy. [ABSTRACT FROM AUTHOR]

This paper investigated the specific compressive strength (specific strength) of fly ash-based geopolymer composites with four hardwood extractives and two softwood extractives, as well as specific wood extractives. Additionally, the effect of the portion of pine wood (i.e., sapwood and heartwood) and wood pretreatment with NaOH were considered. Geopolymer paste (with extractives) and geopolymer wood composites (GWCs) were cured at 60 °C for 24 h. The samples were stored in a climate chamber (20 °C, 65% RH) for 7 days before finally testing under compression. From the results, the specific strengths of geopolymers with hardwood extractives were not significantly affected. However, geopolymers containing pine extractives showed the most significant reduction in specific strength. There were no significant differences in the specific strengths of geopolymers containing polyphenols and resin acid. Generally, geopolymers containing fatty acids recorded the lowest specific strengths. There was no difference between the GWCs with untreated sapwood and heartwood. However, the wood pretreatment led to a 21% and 10% increase in the specific strengths of GWCs with sapwood and heartwood, respectively. The findings of this study form the basis for improved GWCs production and a wide range of applications for green composite materials. [ABSTRACT FROM AUTHOR]

Due to its excellent performance of lightweight and high strength, Al/Mg bimetal has high application value in the aerospace field. However, the poor bonding quality of the Al/Mg bimetallic interface is still an urgent problem to be solved. Therefore, this paper proposes to use Ni foil as the interlayer to control the interface structure and improve bonding strength. The results show that the Ni interlayer has a positive influence on Al/Mg interface structure regulation. The interface is composed of Al3Ni, Al3Ni2 and Mg2Ni phases, and no Al–Mg brittle intermetallic compounds (IMCs) are formed. Meanwhile, the Mg2Ni phase is distributed as islands on the interface at 490 °C, effectively preventing crack propagation. The average shear strength of the interface reaches a maximum of 69.5 MPa. Besides, the interface fracture mechanism was deeply analyzed. The Al/Ni interface has excellent bonding performance, and the fractures occur at the Mg/Ni interface. The fracture mode from intergranular and cleavage mixed fracture at 490 °C to brittle cleavage fracture at 505 °C. [ABSTRACT FROM AUTHOR]

A new type of inorganic fiber-fly ash continuous fiber was innovatively developed in this study to alleviate the problems of low comprehensive utilization rate and lacking of high-value utilization means of industrial solid waste fly ash. The melt flow temperature and macro-mechanical properties of different samples were studied. The results showed that with the increase in acidity coefficient index (MK), the melt flow temperature decreased first and then increased, and the lowest value was 1340 °C when MK was 3.1. Meanwhile, with the gradual increase in MK, the tensile strength and elastic modulus of monofilament increased first and then decreased. When the MK was 3.8, the tensile strength and elastic modulus of fiber monofilament reached 2064 MPa and 16.7 GPa, respectively. According to the results of XRD, TG-DSC, FTIR and SEM microstructure analysis methods, it is found that the macro-mechanical properties of fibers are closely related to the chemical composition and phase structure evolution of raw materials. After melting at high temperature, the samples with high MK form a dense three-dimensional glassy network structure, which leads to the higher mechanical strength of the fibers. However, in the samples with lower MK, the vitreous network structure is loose, which reduces the mechanical properties of the fiber. Finally, the MK range (2.5–3.8) for preparing high-performance fly ash fiber was proposed in this paper. In this range, the synthesized fly ash continuous fiber has low melting temperature and excellent mechanical properties, which has a potential of industrial application. [ABSTRACT FROM AUTHOR]

During high-temperature applications, tensile stability is significantly important and urgent for the security of components. In this paper, the high-temperature tensile tests under different creep strain were performed and analyzed through scanning electron microscope (SEM) and transmission electron microscope (TEM) of TC11 titanium alloy. It is found that the creep strain, dynamic α precipitation and deformation modes have significant influence on the high-temperature tensile behavior of TC11 titanium alloy. An abnormal characteristic of high-temperature tensile stress plateau was observed with the increasing of the creep strain. Moreover, an increment of 100 MPa for yield strength was achieved when the creep strain increased from 0.075 to 0.21%. For low creep strain, sample was controlled by the dislocation slip. While at high creep strain, it promotes the precipitation of nano-sized α particles, and dislocation slip hardly transfers across the α/β interface. Then, dislocation tangles, deformation twins and stacking faults become dominated, which results in an obvious stress plateau in the stress–strain curve. [ABSTRACT FROM AUTHOR]

In this paper, perfect interface model of Al/AlCu alloy and defect interface model of Al/AlCu alloy after cracks were introduced at different positions of the interface were established by using cohesive zone modeling method. Classical molecular dynamics simulation was used to study the deformation behavior and microstructure evolution of Al/AlCu alloy interface model at a strain rate of 0.05 Å/ps and the temperature of 300 K. The simulation results show that perfect interface exhibits a uniform plastic deformation stage due to structural relaxation after yielding, while there is no structural relaxation during the deformation of defect interface and the tensile strength is much lower than that of perfect interface as well. In the process of deformation, stacking faults formed in perfect interface and cracks are generated and expanded in Al matrix, while there was no stacking faults forming along with the expansion and cracking at the position of introduced cracks in defect interface. Massive dislocation nucleation leads to the reduction in stress at the perfect and defect interfaces after yielding. The extension of Shockley partial dislocation and the nucleation of Stair-rod dislocation are the main mechanisms of interface deformation. Densities of Shockley partial dislocation and Stair-rod dislocation decrease with increasing strain before crack propagation. This study enriches the analysis of microstructure evolution of Al/AlCu alloy interface and similar interfaces during deformation. [ABSTRACT FROM AUTHOR]

In this paper, a safe, low-cost and simple operating LiF + HCl etching method combined with freeze-drying was used to prepare Ti3C2TX MXene with different etching states. The results indicated that the morphology of Ti3C2TX gradually changed from stacked to accordion structure and finally to ultra-thin dispersed sheets with increasing etching. We also investigated different surface functionalization and electromagnetic properties of synthesized samples. In 2–18 GHz, the effective absorption bandwidth (EAB) (RL < − 10 dB) of the sample with accordion microstructure reaches 3.92 GHz at thickness of 1.27 mm, while for the ultra-thin dispersed Ti3C2TX sheets, the EAB is increased to 4.40 GHz at thickness of 1.26 mm. To our knowledge, this is the minimum thickness in Ti3C2-related reports. We attribute the improved wave absorption performance to the dielectric and magnetic loss induced by termination layer as well as the unique interface effects, which are also beneficial to optimize the impedance matching and achieve multi-mode attenuation even in high frequency band. [ABSTRACT FROM AUTHOR]

Carbon dots have attracted much attention in the field of antibacterial because of their good biocompatibility, easy preparation, and basically not inducing bacterial resistance. At present, studies have shown that many antibacterial carbon dots have high positive surface potential, but few researchers have been carried out on how to design carbon dots with high positive surface potential by using nontoxic precursors. In this paper, three structurally similar amino acids with different isoelectric points were selected as carbon sources, and three kinds of carbon dots based on amino acid were synthesized with hydrothermal method. The structural characteristics of the three carbon dots were characterized by XRD, FT-IR, XPS, etc. The content of nitrogen-containing groups of the three carbon dots was compared with the Kaiser test. The relationship between the Zeta potential and the antibacterial effect was also investigated. And it shows that the arginine carbon dots, which have the highest positive charge, also have the best antibacterial performance. So, the arginine carbon dots were further doped with nitrogen-containing molecules (diethylenetriamine, DETA) to obtain high surface positive potential carbon dots (named DETA-Arg-CDs, Zeta potential = + 21.7 mV) with the minimum inhibitory concentration (MIC) against E. coli and S. aureus being 8 and 4 ug/mL, respectively. The antibacterial mechanism of high surface positive potential carbon dots was demonstrated by a series of experiments and computational simulations. Cytotoxicity tests showed that the carbon dots were almost nontoxic within the range of antibacterial concentration. Finally, it was applied to the preparation of antibacterial masks. The bacteriostatic zone experiment showed that the mask sprayed with DETA-Arg-CDs had an obvious bacteriostatic zone, while the blank control group had no bacteriostatic zone. In summary, this study synthesized carbon dots with excellent antibacterial properties by using simple and safe amino acids and small nitrogen-containing molecules and explored the antibacterial mechanism of carbon dots with high surface positive charge. [ABSTRACT FROM AUTHOR]

PET (polyethylene terephthalate) being widely used in the manufacturing of bottles, especially in the beverages industry, has obvious advantages over glass bottles and cans, including but not limited to its transparency, robustness, and light weightiness, etc. However, its permeability is a major concern for scientists as it evidently affects the quality of packaged food, especially beverages. The fact that it easily allows gases like oxygen and carbon dioxide to pass through them makes it less effective and least cost-efficient when compared with its substitutes. Alternatively, if its permeability is ameliorated, this can drastically improve the overall statistics of profits in the beverage industry. This paper attempts to improve the gas barrier property of PET via a reduction in carbon dioxide (CO2) permeation. Through temperature-induced solution processing, WS2 (tungsten disulfide) is disseminated in PET. The decrease in CO2 permeability in WS2 nanosheets/PET composites is assessed. After an 11-h test run, free-standing composite membranes demonstrated a maximum 99.9% permeability decrease at extremely low filler loading (0.005 wt% WS2) in contrast to the polymer. It is interesting to note that WS2 loading over 0.005 wt% completely reduced permeation. High-aspect-ratio WS2, homogenous dispersion inside PET, and jiggling effect surrounding nanosheets per flake have all contributed to the gas flow's winding path's complexity. Through the use of models developed by Bharadwaj, Neilson, Lape, and Cussler, experimental findings have been confirmed. SEM evaluates the dispersion state, and X-ray diffraction has validated the formation of composites. Higher mechanical resilience of WS2 nanosheets/PET composites and adhesion property was demonstrated by tensile testing and tribology technique. [ABSTRACT FROM AUTHOR]

The edge-hydroxylated boron nitride nanosheets (BNNS) not only has excellent thermal stability, electrical properties, but also has high specific surface area, good dispersibility and compatibility. In this paper, edge-hydroxylated BNNS was obtained by stripping hexagonal boron nitride (h-BN) using wet chemical reaction method. The hydroxylated structure of the surface and formation mechanism of BNNS were analyzed, and the optimal controlled conditions were explored by orthogonal test. The results showed that the content of N element in the center of the BNNS (46.44 at. %) is significantly higher than that of B element in the edge of the sheets (33.10 at. %), and the content of O element in the edge of the sheets is nearly 30% higher than that in the center. It indicates that the edge of the BNNS introduces more oxygen than h-BN, the nitrogen atoms at the edge are replaced by oxygen atoms to achieve hydroxylation. When the mass ratio of h-BN and potassium permanganate is 1 g: 5 g, the reaction time is 9 h, and the reaction temperature is 60 °C, the obtained nanosheets have the best hydroxylation and good stripping effect. The average lateral size of the exfoliated nanosheets is 123 nm and only about three layers. [ABSTRACT FROM AUTHOR]

Owing to the high demand for electronic devices and electric vehicles, a huge effort has been directed to the exploration and development of new batteries with good cycling stability, satisfactory high specific capacity and safety. In this paper, we report the designed synthesis of the vanadium oxide with mixed valence H2V3O8 and the composite H2V3O8/PEDOT:PSS using low cost and easy hydrothermal method. Electrochemical activity of the vanadium oxyhydroxide H2V3O8 and the composite H2V3O8/PEDOT:PSS as cathodes materials for high performance lithium–ion batteries was evaluated vs. Li+/Li at various current rates. Compared with pure H2V3O8, composite H2V3O8/PEDOT:PSS cathode exhibits higher specific capacity (390 mAh g−1 at 0.05 A g−1 whereas, an initial discharge capacity of 300 mAh g−1 is observed at 0.3 A g−1), more excellent rate performance and longer cycle life. The composite H2V3O8/PEDOT:PSS cathode delivers excellent specific capacity of ca. 390 mAh g−1 and a 97.5% capacity retention are achieved even after 350 cycles at current density of 0.05 A g−1. Higher electrochemical capacity and stability of the new composite cathode are mainly ascribed to a cooperative effect between the conductive polymer (PEDOT:PSS) with good electrical conductivity and the unique nano-sized H2V3O8 rods with short diffusion pathway for lithium ions diffusion. [ABSTRACT FROM AUTHOR]

It has been shown that combining 2D materials in vertical or lateral heterostructures can significantly change and improve their electronic properties, making them more applicable for various purposes, e.g., nanoelectronics, spintronics, energy storage, catalysis etc. In this paper, we employ first principle calculations to investigate the influence of Li adsorption on lateral heterostructures composed of nanoribbons of graphene and hexagonal boron nitride. The results indicate the profound role of the nanoribbon interface. With respect to the sole graphene or boron nitride nanoribbons, Li atoms more strongly adsorb to their lateral interface due to the hybridization of electronic states. This leads to the severe changes in the electronic band structure. Our findings show that in the case of boron terminated zigzag nanoribbon interface, metallic character of the nanoribbon is changed upon Li adsorption. It opens an indirect bandgap of about 0.2 eV, showing that Li adsorption can be used for tuning electronic properties of the nanoribbons. [ABSTRACT FROM AUTHOR]

This paper describes technological processes developed for less studied ZnTe thin films prepared by close space sublimation method, without an additional transport agent gas, for controlling their structural and optical properties. The enhanced oxygen incorporation depends on the source–substrate growth conditions. ZnTe thin films fabricated in the source-substrate temperature interval mentioned here crystallize in a cubic zincblende structure preferentially oriented along the [111] reflection plane. As the source temperature increases, the energy dispersive X-ray spectroscopy shows that the tellurium content increases, while the oxygen decreases. The values of the optical band gaps vary in interval from 2.21 eV up to 2.22 eV with variation of the source temperature, while variation of the substrate temperature leads to the band gap value decrease from 2.24 to 2.14 eV. The photoluminescence spectra of the ZnTe:O thin films are dominated by the red emission bands localized at 1.73 eV and 1.82 eV. This study will serve as a basis for future efforts to develop intermediate-band solar cells with improved conversion efficiency. [ABSTRACT FROM AUTHOR]

High-entropy alloys (HEAs) have attracted extensive attention due to their excellent mechanical properties, thermodynamic stability, tribological properties, and corrosion resistance. In this paper, the tribological properties of HEAs were reviewed, including definition and preparation method of HEAs, testing and characterization method of tribological properties, influence of HEAs components on tribological properties, and anti-wear effect of process optimization. Firstly, the definition of HEAs and the enhancement of high-entropy effect, lattice distortion effect, delayed diffusion effect, and "cocktail" effect were briefly introduced. The advantages and disadvantages of current smelting and powder metallurgy methods were summarized, and various additive manufacturing techniques were discussed for preparing HEAs coatings. Secondly, the testing techniques and characterization methods of tribological properties of alloys were introduced. According to different wear mechanisms, the wear was classified as abrasive wear, adhesive wear, fatigue wear, corrosion wear, and oxidation wear. The research on reactive wear reduction, a new hotspot, was emphatically discussed. Furthermore, the influence of various metal elements and non-metal elements B, C, N, O, and Si in HEAs on tribological properties was analyzed, as well as the anti-wear mechanisms in the doped hard phases and self-lubricating phases. Meanwhile, the strengthening effects of surface remelting, heat treatment, and surface ceramization on the wear resistance of HEAs were reviewed. Finally, although some achievements have been made so far, there are still many challenges in the development of wear resistance for HEAs, and suggestions for future research directions were presented. [ABSTRACT FROM AUTHOR]

Li-rich manganese-based cathode materials are known as one of the most promising cathode materials for next-generation lithium batteries due to their high theoretical specific capacity. However, there are problems such as low specific capacity, poor rate performance, and fast decay rate during cycling. In this paper, spherical lithium-rich manganese-based cathode material Li1.2Mn0.54Ni0.13Co0.13O2 was prepared by co-precipitation method, and aluminum fluoride (AlF3) was prepared by high temperature solid state reaction, so that AlF3 was uniformly coated on lithium-rich manganese-based cathode. The results show that AlF3 is uniformly coated on the surface of the spherical Li1.2Mn0.54Ni0.13Co0.13O2 material with a thickness of about 5~7 nm, and the material maintains the original layered structure without changing. The charge–discharge cycle test was carried out in the voltage range of 2.0~4.8 V, and the specific capacity of the Li-rich manganese-based cathode material coated with AlF3 was significantly improved, reaching 283.3 mAh/g (Under the same preparation method and test conditions, this value is in the forefront of the 260–290 mAh/g that can be achieved by most of the current coating methods). The AlF3 coating with the best retention performance is 4 wt% and still has a retention rate of 84.4% after 200 charge–discharge cycles. During the charging and discharging process, AlF3 can maintain the stability of the main cathode material and inhibit the next transformation, thereby ensuring the high specific capacity and cycle stability of the material. [ABSTRACT FROM AUTHOR]

In this paper, we proposed a method of strengthening Sn-based solder to retard the microstructural evolution during thermal cycling and thus to improve the thermal fatigue life of Sn-based solder joint. We fabricated a multiple-elemental Sn-based solder by adding Ni, Bi and Sb into the Sn3.0%Ag0.5%Cu (SAC305) solder. Thermal cycling tests (− 55 °C ~ 150 °C) were performed on the prepared multiple-elemental Sn-based solder joints and SAC305 solder joints, and quasi-in situ observation was accompanied by the thermal cycling test to identify and compare the corresponding microstructural evolution process. It turned out that the intragranular dislocation movements were effectively hindered at the early stage of thermal cycling, which was due to the effects of solid solution strengthening. Furthermore, the motion of pre-existing grain boundaries and hysteresis of dislocation slip played a predominated role in the strengthened multiple-elemental solder joints. By contrast, the aforementioned two phenomena occurred concurrently in the non-strengthened solder joints. As a consequence, the multiple-elemental solder joints retained the integrity of solder joints after 1200 thermal cycles. This phenomenon indicates that the microstructural evolution was significantly delayed compared with the pristine SAC305 solder joints during thermal cycling. Therefore, SACNSB solder joints have a longer thermal fatigue life. The idea of retarding microstructure evolution during thermal cycling by strengthening Sn matrix can help open a new pathway to improve thermal fatigue life of Sn-based solder joints. [ABSTRACT FROM AUTHOR]

The massive residues of tetracycline (TC) have caused serious harm to the human body and the environment, so it is urgent to explore a portable, on-site, sensitive and selective method to detect TC. In this study, a dual response ratiometric fluorescent probe (S,O-C3N4QDs-CitNa-Eu3+) for detecting TC was constructed by mixing sodium citrate (CitNa), europium ion (Eu3+) and sulfur and oxygen co-doped graphite phase carbon nitride quantum dots (S,O-C3N4QDs) solution in a specific proportion. The S,O-C3N4QDs was initially synthesized by using citric acid and thiourea as the precursors via a hydrothermal route. The blue fluorescence of S,O-C3N4QDs (λem = 445 nm) was decreased while the red fluorescence of Eu3+ was increased (λem = 620 nm) own to the synergistic effect of internal filter effect, static quenching and antenna effect when TC was added to the mixed system containing CitNa and Eu3+. As a result, the ultra-sensitive detection of TC was realized from 0.25 to 120 μM with a detection limit of 1.3 nM. An obvious color change of the solution from blue to purple to red with continuous adding TC was observed such that the semi-quantitative detection of TC can be realized. Moreover, a smartphone APP monitoring platform based on test paper was constructed by using color scanning application, demonstrating that the ratiometric fluorescent probe constructed in this work has great potential in medical and environmental fields. [ABSTRACT FROM AUTHOR]

Nanostructured transition metal phosphides (TMPs) have emerged as an attractive material in energy storage domains, owing to their high electrical conductivity and easy redox properties. However, the low actual specific capacitance and weak cycling stability hinder its further application. In this paper, the hierarchical nanosheet of CoP nanoparticles embedded in a two-dimensional carbon skeleton (Co-NP@C) with flake-like ZIF-67 as its precursor was synthesized by facile carbonization and phosphorization and employed as positive electrodes for asymmetric supercapacitors. Due to the presence of carbon skeleton and nanoparticles, a stable structure and more reaction channels for the electrochemical reactions were created, leading to a remarkable improvement of the electrical properties of Co-NP@C. The Co-NP@C electrode presents the exceptional electrochemical performance of 540 F g−1 at 1.0 A g−1. Furthermore, an asymmetric symmetric supercapacitor with Co-NP@C cathode and reduced graphene oxide (RGO) anode achieves superior cycling stability (92.4% after 10, 000 cycles at 10 A g−1) and a high energy density of 20.22 Wh kg−1 at a power density of 649.93 W kg−1. This study offers a simplified method for guiding the design of MOF-derived phosphide electrode materials and provides additional opportunities for optimizing high-efficiency supercapacitors. [ABSTRACT FROM AUTHOR]

Understanding the fracture behavior of concrete plays a major part in predicting and designing novel high-performance and functional concrete materials. This paper presents a new numerical model based on Peridynamics (PD) for investigating the fracture behavior and mechanical properties of concrete, in terms of the effect of boundary friction, randomness, and slenderness. Meso-structure models of concrete were constructed to perform uniaxial compression tests. The results show that due to the restraint of boundary friction, the peak stress, fracture energy, and peak strain under high friction (HF) boundary condition are higher than that under low friction (LF) case implying that the specimen in the HF case can sustain larger deformation and bear higher stress. In term of fracture pattern, in the LF case, the cracks are free to propagate along the weakest part of the concrete specimen and form vertical cracks paralleled to the compressive loading direction while under the HF boundary condition the frictional restraint in cracks has an impact on the fracture process as the boundary friction can prevent local fracture. The randomness introduced to account for the heterogeneity of concrete material will cause a decrease in strength and an increase in the damage degree of specimens. The slenderness has a strong effect on the mechanical properties of specimens: the stress and fracture energy increase with the decreasing slenderness. The simulated mechanical properties and fracture patterns in this study agree well with experimental results indicating that the application of PD theory in concrete has sufficient accuracy. [ABSTRACT FROM AUTHOR]

As a typical representative of Ga-based III-V compound semiconductor material, the pressure-induced structural phase transition of gallium phosphide (GaP) has received more attention, while the present work explains the electronic structure and photoconductivity properties under high pressure, especially. The paper focuses on the high-pressure electronic structure and photoconductivity properties up to 50.0 GPa in GaP, along with the ZB (zinc-blende structure) to RS (rock salt structure) phase structural transition using enthalpy calculation. The discontinuous thermal expansion coefficient and unit cell volume collapse by 15.0–15.5% are observed at around 39.2 GPa due to reversible structural phase transition under compression and decompression conditions, which is also reflected in the measured discontinuous Hall coefficient and conductivity at approximately 39.0 GPa. The computed semiconductor-to-metal transition is determined to occur at 24.5 GPa by band-gap closure in good agreement with the experimentally determined transition pressure. The light illumination provides a potential way to reduce conductivity without effect on pressure of phase transition. [ABSTRACT FROM AUTHOR]

According to the design concept of hollow metallic microlattices, the quality of the coating has a considerable influence on the performance of the material. To avoid the effect of by-products in the coatings, we have chosen the Al-induced electroless plating method to respond to the composition design of this material. In this paper, the coatings formation process of Al-induced electroless plating on the metallic surface is systematically investigated. The coatings created by Al-induced electroless plating were characterized by surface morphology, XRD patterns, and electrochemical potential. Subsequently, the deposition process of elements on the metallic substrate was simulated by molecular dynamics. Finally, the surface morphology changes of coatings were observed at different plating times to verify the simulation results. The results indicate that the four kinds of coatings are each composed of a single metal element (copper, cobalt, nickel, and iron) with no by-products. Based on the results of morphology changes of the coatings and the deposition simulation, the overall formation process of Al-induced electroless plating is described. The deposition of coatings has the characteristics of preferential growth and aggregate growth. The metal atoms that are generated from the reaction of the reducing electrons with the target metallic ions in the solutions are deposited on the substrate surface as the primary cores. The reducing electrons are provided by the dissolution of Al foil. With the increase in the number of generated metal atoms, multiple atomic clusters form in the areas of the primary cores. These clusters develop at various scales on the substrate surface, forming irregular particles. Eventually, coatings are formed completely with uniform particle sizes. [ABSTRACT FROM AUTHOR]

Since the second half of the 20th century, bioceramics are widely used as a substitute for hard tissue engineering. Bioceramics including zirconia, alumina, hydroxyapatite, and bioactive glass plays a vital role in the design of tissue engineering scaffolds with tailor-made properties. The bioceramics scaffold has been used to replace or regenerate the tissue of the human body due to its excellent mechanical strength, biocompatibility, chemical stability, corrosion restriction behavior, and wear resistance. The advancement in technology has made the form of bioceramics and their function, structure, and composition more diversified, and manifold. Considering the promising role of the use of bioceramics in tissue engineering, we proposed this review, presenting the classification of bioceramics, their physiochemical properties, degradation pathway, product development so far, and their application in tissue engineering. The calcium phosphate and bioglass-based composite scaffold have also been discussed in detail. Furthermore, this paper also discussed the toxicity evaluation and market perspective of bioceramics. Thus, this review gives a complete insight into bioceramics for tissue engineering applications. [ABSTRACT FROM AUTHOR]

Inspired by animals or plants in nature, the surface of many industrial products is endowed with superhydrophobic properties according to the principle of bionics, thus solving multiple industrial problems, such as self-cleaning, underwater drag reduction, droplet or bubble control, delayed icing, corrosion prevention, biomimetic deposition, optical applications, anisotropy, oil–water separation and so on. As an advanced method for preparing superhydrophobic surfaces, laser biomimetic manufacturing has the characteristics of high efficiency, flexibility and controllability. Therefore, laser biomimetic manufacturing technology has received extensive attention in recent years, and has been widely studied in the superhydrophobic fields. This paper highlights the latest research progress of application of functional superhydrophobic surface prepared by laser biomimetic manufacturing. Finally, the future research directions for functional superhydrophobic surface are discussed, and the development has been prospected. [ABSTRACT FROM AUTHOR]

The photothermal process exhibits the largest energy conversion efficiency among all solar energy utilization processes. In this study, a core–shell CoTiO3@MnO2 (CTM) composite photothermal catalyst was synthesized by supporting MnO2 on CoTiO3 by hydrothermal synthesis. Binding to peroxymonosulfate (PMS) heterogeneous catalyst removed tetracycline in wastewater. The new catalyst was characterized by FT-IR, UV–Vis, XRD, BET, SEM, TEM, and so on. Kinetic analysis showed that CTM activated PMS at a rate of 3.2 and 3.5 times higher than that of pure light and heat conditions, with complete degradation of tetracycline (TC). Since the outer MnO2 layer converted the absorbed solar energy into thermal energy, PMS was activated to generate active species while performing electron transfer, which resulted in a considerably improved catalytic efficiency. To prove the wide applicability of the catalyst, other pollutants were degraded, including bisphenol A (BPA), metronidazole (MNZ), and methyl orange (MO). The three pollutants were degraded within 40 min. Finally, our findings demonstrated the mechanism of the photothermal degradation process and provided a novel approach for environmental remediation using renewable solar energy. In this paper, the degradation efficiency of CoTiO3 was improved by loading MnO2 on CoTiO3. Binding to peroxymonosulfate (PMS) heterogeneous catalyst activation for the catalytic degradation of tetracycline. It was found by experiments that the core-shell structure of the composite material CoTiO3@MnO2 had better photothermal catalysis efficiency than photocatalysis and thermal catalysis. [ABSTRACT FROM AUTHOR]

The impact of crushing on the macroscopic mechanical characteristics of granular materials from a microscopic perspective has recently been revealed using the discrete element method (DEM). The influence of the self-organized, mass conservation and volume conservation of daughter particles in the fragment replacement method (FRM) on particle breakage is complex and crucial. In this paper, 14-ball Apollo directly filling method (DFM) and expansion method are combined to keep balance among particles before and after crushing, considered to establish DEM to simulate granular material. By considering the influence of volume loss on the micro-fracture condition of the samples, the macro-responses of mechanical and deformation characteristics, the gradation change and the critical state are studied. The effect of inter-particle interaction on macroscopic properties is also analyzed from the microscopic perspective. The rationality of the volume expansion method is verified. The comparisons of samples with volume conservation and volume loss show that the stress development process and the volumetric strain are affected. The existence of the balance point of volume effect is related to the stress level which lead to the difference in stress and strain. Through analysis of relative breakage index (Br) and the statistical number of microscopic particles, it can be seen that the gradation deviation comes from the two-way influence of the volume loss on the crushing of particles. The volume loss has no effect on stress ratio in the critical state, but has a significant effect on stress change during shearing process, and results in the critical state void ratio to decrease with increasing confining pressure. The rationality of daughter particles' volume conservation are analyzed from the motion, displacement development and force chain evolution. [ABSTRACT FROM AUTHOR]

In this paper, the effects of nitrogen doping and oxygen vacancies on thermoelectric properties of Pt/N-doped ITO thin film thermocouples were discussed in detail from the perspective of thermodynamics and kinetics based on first-principles and experiments. The atomic structure and bonding characteristics of ITO and N-doped ITO were investigated by X-ray diffraction and X-ray photoelectron spectroscopy. The calculation results show that nitrogen doping makes the charge transfer to the Sn-N bond and produces anti-bonding states to the nearest neighbor Sn–O bond, so that the repair of oxygen vacancies in N-doped ITO requires a higher activation energy than ITO. The effects of band structure, carrier concentration and carrier effective mass on the Seebeck coefficients of ITO and N-doped ITO were further discussed in detail. Finally, Pt/ITO and Pt/N-doped ITO thin film thermocouples were fabricated on the Al2O3 substrates by magnetron sputtering to verify their thermoelectric stability. The calibration results also proved that N-doped ITO has higher thermoelectric stability than ITO. [ABSTRACT FROM AUTHOR]

Based on the multi-physical field coupling analysis method, a finite element meso model of an induction heating circular tube containing carbon fiber texture and resin matrix is established, and the change law of the temperature field and stress of the circular tube is verified by experiments in order to study the distribution and change law of each physical field of induction heating technology in the heating process of a carbon fiber composite (CFRP) circular tube. This paper's electro-magnetic thermal mechanical coupling analysis model is shown to be accurate. The temporal and spatial variation laws of the temperature field, curing degree, and stress field in the process of multi-coil heating in a CFRP circular tube are investigated using the analytical model. The induction heating method of magnetic field superposition and coupling is proposed to improve the forming quality of carbon fiber circular tubes. The coupling state between magnetic fields changes with time, resulting in the dynamic change of eddy current and heat generation in the material and improving the uniformity of heat distribution in the periodic range which can effectively improve the uniformity of the temperature field, curing degree, and stress distribution of circular tubes and improve the quality of CFRP circular tubes in the forming process. [ABSTRACT FROM AUTHOR]

Cellulose is a common natural polymer, and the surface of the nanocellulose has a large number of hydroxyl groups, which is possible used to precipitate metal salts to obtain the precursors, and then calcine to get the corresponding metal oxides. In this paper, tin dioxide (SnO2) nanoparticles were prepared with different amounts of nanocellulose by a low-temperature hydrothermal method (60°C) followed by calcination. The obtained material was verified to be impurity-free SnO2 nanoparticles by various types of physical phase analysis and morphological characterization. The SnO2 nanoparticles obtained from 50 mg nanocellulose exhibited a significantly improved sensing performance, and the response toward SO2 at 1 ppm was 4.68. In addition, multiple performance tests were conducted on the obtained gas sensor, and it was finally found to have a good gas sensitivity and an excellent selectivity. The repeatability and stability also presented preferable results. Additionally, the sensing mechanism was discussed. The prepared SnO2 sensor is promising for the detection of SO2 due to its high sensitivity and selectivity. [ABSTRACT FROM AUTHOR]

The new polypyrrole tin boratophosphate (PTB) material has been synthesized for the first time in this work. A series of characterization analyses of the PTB by FTIR, XRD, TGA, SEM, TEM and EA have proved that PTB is amorphous ion nanocomposites, which shows that the PTB has excellent chemical stability in complex acidic and organic environments and commendable selectivity for Pb2+ as well. The adsorption mechanism of the PTB adsorption process was studied in detail from the aspects of thermodynamics, kinetic and adsorption isotherm. It is proved that the adsorption kinetic model conforms to the quasi second-order kinetic model, while the adsorption isotherm is consistent with the Langmuir model. It is also proved that the adsorption of Pb2+ ions by the PTB is spontaneous endothermic process. In conclusion, the PTB cation exchange material synthesized in this paper has a good application prospect in the removal of Pb2+ from industrial and domestic sewage. [ABSTRACT FROM AUTHOR]

In this paper, the anti-aging properties of composites doped with nano and micro BiFeO3 and treated with different magnetic fields were studied by scanning electron microscopy (SEM), infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and broadband dielectric spectroscopy. SEM results showed that thermal aging had a significant effect on LDPE and composites, and the effect of magnetization treatment on the structure was significantly weakened. FTIR results showed that with the increase in aging time, the carbonyl content increased, the carbonyl content of nanocomposites increased less, and the carbonyl content of micron composites increased gently. DSC results showed that the addition of BiFeO3 acted as heterogeneous nucleation agent, and the orientation of magnetic field changed the arrangement of molecular chain and improved the crystallinity of the composite. Compared with the aged LDPE, the aged composite had lower dielectric constant and loss factor. 0.2 wt% nano and micro BiFeO3/LDPE composites had significant anti-aging ability, and the dielectric constant and loss factor of the composites could be further reduced by magnetic field treatment. All the test results showed that the doping of BiFeO3 and magnetic field treatment could change the internal structure of the composite, increase the compactness of the material, and make the composite have obvious thermal aging resistance. [ABSTRACT FROM AUTHOR]

Montmorillonite is a natural clay mineral linked with the smectite group of a dioctahedral 2:1 phyllosilicate formed by two tetrahedral sheets along with one octahedral sheet. In contradiction to other clay nanoparticles, the montmorillonite confers an interlayer spacing on either side of each triple-sheet layer. MMT was fashioned by dissolving rocks and minerals on Earth's surface. The remarkable qualities responsible for the reinforcing efficiency of MMT include greater surface area and a higher aspect ratio. These qualities confer distinctive thermal, gas barrier, mechanical and rheological properties to MMT-rubber or polymer composites. It is also used as a promoter of rubber particle size reduction in polymer or rubber matrices and has attracted diverse merits for material applications globally. MMT displays potential for use as active agents and as an alternative to other expensive nanoparticles in the fabrication of multi-use and high-quality rubber nanocomposites. Rubber nanocomposites filled with MMT showed superior viscosity, toughness, and rigidity with less tensile strength and elongation at break. This paper reviews current multi-advancements in montmorillonite rubber or polymer nanocomposites (MMT-RCNs/PCNs): applications of MMT-RCNs/PCNs in aerospace, automobile, food additives, antibacterial, polymer, sorbent, catalyst, pharmaceutical, tissue engineering, biosensing, drug release and the utilization of polymer-based hydrogels investigated at both 2D and 3D nanoclay particles for various applications. [ABSTRACT FROM AUTHOR]

To develop green thermal insulation materials made of straw to replace high energy consumption and high pollution materials, such as asbestos and polystyrene, this paper reviews the relevant characteristics of straw as a thermal insulation filler and the research progress of mechanical straw building materials (i.e., the straw filler is placed in the interlayer and fasted by friction or gravity). Research studies on straw combustion, moisture absorption, and heat transfer mechanisms are reviewed. Additionally, the research status of three kinds of mechanical straw building materials, namely straw bales/laminated wallboards, beetle elytron plate walls, and mixed straw fillers, is also explained. This assessment shows that straw thermal insulation fillers have good fire safety and thermal insulation performance. The straw bale/laminated wallboard system is mature, with rich varieties and practical applications, while beetle elytron plate walls and mixed straw fillers are still in the development stage. Although there are many related research results, more reports on the heat transfer mechanism, material selection, and application forms are needed, which is an important direction for future systematic research. Actively promoting the application of green mechanical straw-filled sandwich structures in more fields will produce good social and economic benefits. [ABSTRACT FROM AUTHOR]

To meet the polarization adaptation in communication systems, it is necessary to improve the performance of polarization converters. Microwave dielectric materials are very promising to optimize the response speed, operating frequency, conversion efficiency, and transmission stability of polarization converters, which puts higher demands on ceramic materials. In this paper, the microwave dielectric properties of Ca5Mn4(VO4)6 ceramics are improved by using Cu2+ instead of Mn2+. The effects of Cu2+ substitution and sintering temperature on microwave dielectric properties are also investigated. The substituted ceramics have excellent microwave dielectric properties of εr = 11.4, Q × f = 42709 GHz, and τf = − 65 ppm/°C. As a concept demonstration, a new 5G polarization converter between linear polarization and left-handed circularly polarized (LCP) waves is designed by using this ceramic substrate. By observing the surface electric field and surface current, it can be judged that the principle of the polarization converter is the difference in the electric dipole resonance absorption between the LCP and the right-handed circularly polarized (RCP) waves. The simulation results of normalized reflectivity and far-field (electric field and phase) show good performance of the polarization converter. [ABSTRACT FROM AUTHOR]

Heterogeneous, sulfate radical-based advanced oxidation processes (AOPs) have arisen in recent decades due to their high reactivity and oxidation capabilities for a wide spectrum of hazardous and refractory organic compounds. The presence of a rate-limiting step with a slow conversion rate from ≡Me(n+1)+ to ≡Men+ in transition metal oxides, on the other hand, severely limits the performance of PMS activation. Also, the activity of metal catalysts is pH-sensitive. Herein, we provide a promising strategy to solve these issues. In this paper, Cu/Mn–ZnO nanoparticles consisting of dual reaction centers (DRCs) with electron-rich/poor areas were synthesized by hydrothermal methods, which demonstrated high activity, stability, and reusability in heterogeneous catalysis. Characterization results (e.g., XPS) revealed that the catalysts present surface electron-rich Cu & oxygen vacancies (OVs) centers/deficient micro-areas, avoiding direct reaction with metal ions, while pollutants can be captured and preliminarily degraded by the electron-deficient areas as electron donors. As a result, the structure eliminated the influence of pH on activity in the range of 2.5–10.5 and exhibited significant catalytic activity. Using Rhodamine B (Rh-B) as the target pollutant, the degradation rate was up to 96% at 10 min. Moreover, the EPR analysis and quenching experiments revealed that 1O2 was the predominant reactive oxygen species (ROS) attacking the pollutants. Overall, the catalyst developed in this study has great potential for the treatment of refractory pollutants by activating peroxymonosulfate (PMS). [ABSTRACT FROM AUTHOR]