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Severe challenges are restraining the practical application of solid-state batteries, such as the dendrite growth and unsatisfactory compatibility between solid electrolyte and electrode. Here, we propose an interface dynamic control (IDC) strategy to ensure the stable operation of NASICON-based solid-state sodium batteries. First, we introduce intergranular phase (CuO) to effectively promote the densification of Na

In this study, a finite element low-velocity impact model of Twaron®plain-woven fabric was created and analyzed using the commercial code ANSYS®-AUTODYN, and then was validated by drop-weight impact experiments. As a bullet or a fragment can strike a protective system from any angle in space, it is necessary to investigate fragment impact behavior response to impact threats from all angles of space. Therefore, in-plane obliquityθ, and spatial obliquityφ, were employed in this study and 17 different simulation test impact scenarios with different impact obliquity values were carried out using a standard hemispherical-head impactor. Results showed that the energy absorption of Twaron®fabric decreases with increasingθ, whereas under the sameθ, the energy absorption increases with increasingφ. This study also evaluated and compared the low-velocity impact performance of Twaron®fabric as a function of impactor shape, such as hemispherical, flat, and ogival heads, with differentθ. The results showed that under the same density, volume, and diameter conditions and at the normal impact scenario of a flat-head impactor, the fracture mechanism of the yarn is the same with all impact scenarios for a hemispherical-head impactor; the contacted yarns of the fabric fractured almost simultaneously. For the other oblique impact scenarios of the flat-head impactor, as well as impact scenarios of the ogival-head impactor, the yarns of the fabric fractured intermittently. Additionally, for the impact scenario with the ogival-head impactor, the effect of impact obliquity on energy absorption of the fabric was completely opposite to that of the hemispherical-head impact scenario. This is because in the hemispherical-head impact scenario, the fabric yarn tends to be damaged by tension, whereas in the ogival-head impact scenario, the fabric tends to be damaged by out-of-plane shear. These findings provide important guidance for the engineering of soft body armor and composite materials.

(Li1+, Al3+) co-doped Ni0.5Zn0.5Fe2O4 ferrites, Ni0.5-xZn0.5-xLixAlxFe2O4 (x = 0.000, 0.025, 0.050 and 0.100), were synthesized by the sol-gel auto-combustion method. X-ray diffraction (XRD), field emission scanning electronic microscope (FESEM), vibrating sample magnetometer (VSM) and LCR meter were used to investigate the structural, magnetic and dielectric properties. Results of XRD and SEM indicate that both doping amount and calcination temperature play significant roles in crystal structure and grain growth. Also, it can be observed that the saturation magnetization and the coercivity change in a noticeable manner. The Ni0.475Zn0.475Li0.025Al0.025Fe2O4 ferrite sintered at 1200 °C has a relatively low coercivity value (62.93 Oe) and the largest saturation magnetization (110.95 emu/g). Besides, dielectric behavior is also improved by Li1+ and Al3+ co-doping.

Rapid developments in the electric industry have promoted an increasing demand for lithium resources. Lithium in salt lake brines has emerged as the main source for industrial lithium extraction, owing to its low cost and extensive reserves. The effective separation of Mg2+ and Li+ is critical to achieving high recovery efficiency and purity of the final lithium product. This paper summarizes Mg2+/Li+ separation materials and methods in the field of lithium recovery from salt lake brines. The review begins with an introduction to the global distribution and demand for lithium resources, followed by a description of the materials used in various separation techniques, including precipitation, adsorption, solvent extraction, nanofiltration membrane, electrodialysis, and electrochemical methods. A comparison, analysis, and outlook of such methods are comprehensively discussed in terms of principles, mechanisms, synthesis/operation, development, and industrial applications. We conclude with a presentation of challenges and insights into the future directions of lithium extraction from salt lake brines. A combination of the advantages of various materials is the most logical step toward developing novel methods for extracting lithium from brines with high separation selectivity, stability, low cost, and environmentally friendly characteristics.

Although many kinds of flexible piezoelectric materials have been developed, there were few reports on flexible multifunctional nanofibers for energy harvesting. In this study, we prepared multifunctional nanofibers from lead zirconate titanate particles and shape memory polyurethane by electrospinning. The resulting nanofibers had both piezoelectric and shape memory effects. To improve the dispersion, lead zirconate titanate particles were modified by silane coupling agents. The lead zirconate titanate/shape memory polyurethane nanofibers were used to harvest energy from sinusoidal vibrations, and the lead zirconate titanate 80 wt% sample produced voltages of 120.3 mV (peak-to-peak). Taking advantage of the shape memory effect, the lead zirconate titanate/shape memory polyurethane nanofibers can be easily deformed into desired shapes and revealed the potential for realizing energy harvesting in complex structures.

Structural health monitoring (SHM) is vital to the maintenance of civil infrastructures. For rail transit systems, early defect detection of rail tracks can effectively prevent the occurrence of severe accidents like derailment. Non-destructive testing (NDT) has been implemented in railway online and offline monitoring systems using state-of-the-art sensing technologies. Data-driven methodologies, especially machine learning, have contributed significantly to modern NDT approaches. In this paper, an efficient and robust image classification model is proposed to achieve railway status identification using ultrasonic guided waves (UGWs). Experimental studies are conducted using a hybrid sensing system consisting of a lead–zirconate–titanate (PZT) actuator and fiber Bragg grating (FBG) sensors. Comparative studies have been firstly carried out to evaluate the performance of the UGW signals obtained by FBG sensors and high-resolution acoustic emission (AE) sensors. Three different rail web conditions are considered in this research, where the rail is: (1) intact without any defect; (2) damaged with an artificial crack; and (3) damaged with a bump on the surface made of blu-tack adhesives. The signals acquired by FBG sensors and AE sensors are compared in time and frequency domains. Then the research focuses on damage detection using a convolutional neural network (CNN) with the input of RGB spectrum images of the UGW signals acquired by FBG sensors, which are calculated using Short-time Fourier Transform (STFT). The proposed image classifier achieves high accuracy in predicting each railway condition. The visualization of the classifier indicates the high efficiency of the proposed paradigm, revealing the potential of the method to be applied to mass railway monitoring systems in the future.

In view of high-performance, multifunctional, and low-carbon development of infrastructures, there is a growing demand for smart engineering materials, making infrastructures intelligent. This paper reports a new-generation self-sensing cementitious composite (SSCC) incorporated with a hierarchically structured carbon fiber (CF)-carbon nanotube (CNT) composite filler (CF-CNT), which is in situ synthesized by directly growing CNT on CF. Various important factors including catalyst, temperature, and gas composition are considered to investigate their kinetic and thermodynamic influence on CF-CNT synthesis. The reciprocal architecture of CF-CNT not only alleviates the CNT aggregation, but also significantly improves the interfacial bonding between CF-CNT and matrix. Due to the synergic and spatially morphological effects of CF-CNT, that is, the formation of widely distributed multiscale reinforcement networks, SSCCs with CF-CNTs exhibit high mechanical properties and electrical conductivity as well as excellent self-sensing performances, particularly enhanced sensing repeatability. Moreover, the SSCCs with CF-CNTs are integrated into a full-scale maglev girder to devise a smart system for crack development monitoring. The system demonstrates high sensitivity and fidelity to capture the initiation of cracks/damage, as well as progressive and sudden damage events until the complete failure of the maglev girder, indicating its considerable potential for structural health monitoring of infrastructures.

In this work, gold and bismuth bimetallic nanoparticles decorated L-cysteine functionalized graphene oxide nanocomposites (Au-BiNPs/SH-GO) were prepared and applied to selective detection of Fe(III) in lake and seawater samples by modifying onto glassy carbon electrodes. Bimetallic nanoparticles have various excellent properties and better catalytic properties because of the unique synergistic effect between metals. The modified electrode was characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and Raman spectroscopy. Under optimized conditions, current peak intensity increased linearly with increasing Fe(III) concentration over the range of 0.2–50 μM and a detection limit of 0.07 μM (S/N = 3). The Au-BiNPs/SH-GO/GCE was used for the determination of Fe(III) in lake and seawater samples with recoveries ranged from 90 to 103%. Those satisfactory results revealed the potential application of the Au-BiNPs/SH-GO electrochemical sensor for heavy metals detection in environmental monitoring.

This work performs a detailed theoretical analysis for low-concentration solar thermophotovoltaic (STPV) system with both solar absorber and thermal emitter made of previously-developed selective metafilms along with a cavity reflector for performance enhancement. When paired with an InGaAsSb cell, the initial metafilm structure shows an STPV system efficiency of 7.1% at 50 suns, where about half of the incident solar energy is lost through the thermal emission from the top surface of the absorber according to energy loss analysis. In order to enhance the STPV system performance, the metafilm layer thicknesses of the solar absorber and those of the thermal emitter are optimized at 50 suns, increasing the STPV system efficiency from 7.1% to 10.2%. Moreover, a cavity reflector above the absorber is considered to recycle the infrared photons emitted from the top surface of the absorber. The effects of the size and the reflectivity of the cavity reflector on the efficiency are discussed. The results show that, the efficiency of the optimized metafilm based STPV system at 50 suns can be increased from 10.2% to 17.4% with a cavity made of ideal reflectors.

Nature employs supramolecular self-assembly to organize many molecularly complex structures. Based on this, we now report for the first time the supramolecular self-assembly of 3D lightweight nanocellulose aerogels using carboxylated ginger cellulose nanofibers and polyaniline (PANI) in a green aqueous medium. A possible supramolecular self-assembly of the 3D conductive supramolecular aerogel (SA) was provided, which also possessed mechanical flexibility, shape recovery capabilities, and a porous networked microstructure to support the conductive PANI chains. The lightweight conductive SA with hierarchically porous 3D structures (porosity of 96.90%) exhibited a high conductivity of 0.372 mS/cm and a larger area-normalized capacitance (Cs) of 59.26 mF/cm2, which is 20 times higher than other 3D chemically cross-linked nanocellulose aerogels, fast charge-discharge performance, and excellent capacitance retention. Combining the flexible SA solid electrolyte with low-cost nonwoven polypropylene and PVA/H2SO4 yielded a high normalized capacitance (Cm) of 291.01 F/g without the use of adhesive that was typically required for flexible energy storage devices. Furthermore, the supramolecular conductive aerogel could be used as a universal sensitive sensor for toxic gas, field sobriety tests, and health monitoring devices by utilizing the electrode material in lightweight supercapacitor and wearable flexible devices.

Highly aligned nonwoven vapor grown carbon fibre (VGCF) based polyurethane (PU) fibrous membrane (VGCF@PUFM) was fabricated by rotation spinning based on DMF-H2O exchange for directional microwave shielding. This VGCF@PUFM showed obviously different electrical conductivity and mechanical strength in parallel and perpendicular directions. Variational microwave shielding effectiveness (SE) could be observed by changing the rotation angles of VGCF@PUFM with vibrational direction of electromagnetic (EM) wave. There was the shielding difference more than 10 dB (above 20 dB in 0°, below 8 dB in 90°). Greater shielding effectiveness could be expected by enhancing the anisotropy of electrical conductivity of the VGCF@PUFM. In addition, oriented alignment of VGCF in fibre is promising for further improvement of the electrical conductivity in fibre direction.

Herein we present our research on a novel three phase antibacterial wound dressing prepared from carbon nanotubes, silver nanoparticles (AgNPs) and polyvinyl alcohol nanofibers. The AgNPs were generated on carbon nanotubes surfaces to synthesize carbon nanotubes-AgNP nanoparticles which were added into the polyvinyl alcohol nanofibers prior to electrospinning to prepare PVA/carbon nanotubes-AgNP composite nanofibers. All characterizations confirmed the three phase nanofiber architecture. Owing to growth of AgNPs on carbon nanotubes surfaces and embedding into PVA nanofibers the wound dressings are proposed for sustained and safer wound healing applications. The antibacterial test results confirmed excellent bactericidal and prolonged bacterial growth inhibition properties of the nanocomposites which suggest their suitability as sustained antibacterial wound dressing biomaterial.

Shape memory driving thickness adjustable graphite (G) micro-flakes@shape memory polyurethane (G@SMPU) sponge was fabricated by two-step dipping separately in G-dispersed aqueous solution and SMPU/THF solution for high-performance microwave shielding. The sponge exhibited an ultrahigh G loading ratio (G/sponge, wt/wt) up to 490 wt%. For the first time, dipping coating of SMPU onto the sponge was proposed, and the obtained G@SMPU sponge exhibited a good recovery effect at least above 90% after thorough compression. And also, the thickness could be adjusted by utilizing its shape memory property. For microwave shielding, G-9@SMPU and G-18@SMPU sponges achieved the shielding effectiveness over 20 and 30 dB, respectively. Moreover, varying thickness or compressing repeatedly even up to 100 times would not obviously decrease the shielding effect of the G@SMPU sponge. This suggests the steady distribution and adhesion of G micro-flakes inside the three-dimensional sponge substrate due to the fixing of SMPU.

The squared envelope spectrum (SES) is one of the most effective methods in rolling element bearing fault diagnosis. Being a technique based on demodulation, the success of SES depends highly on the extraction of information caused by the bearings fault. Therefore, a preprocessing step of choosing an optimal frequency band (OFB), before the implementation of the SES, is absolutely needed and should always be taken prior. Fast kurtogram (FK), as the most commonly used method targeting resonance frequency band which is excited by the bearing fault, is applied as the benchmark tool for the selection of the OFB. However, recent theoretical works show that the kurtosis used as the criterion for OFB selection was both sensitive to the impulsiveness and cyclostationarity, which means irrelevant impulsive and cyclostationary components are able to mislead the kurtosis based OFB selection techniques and subsequently bring great difficulties in bearing fault diagnosis. To tackle this problem, in this paper, a novel statistical model parameter-based method, called Distcsgram, is proposed as a substitution to the traditional FK technique so that an OFB can be selected with the least influences from the irrelevant cyclostationary and impulsive interferences. Together with the SES, the Distcsgram is explained and validated in both simulation and experimental studies. Furthermore, through the comparisons with the traditional methods, the superiority of the proposed method over those traditional methods for the diagnosis of rolling element bearing is proved.

Under strong winds, the effect of sudden windbreak transition (WT) on high-speed trains is severe, leading to a deterioration of train aerodynamics and sudden yawing motion of the car body. To address these problems, based on a high-speed train and the specific geometric conditions derived from Xinjiang railway, first, the impact of a WT on the train and reasons for sudden changes in aerodynamic forces were determined by flow structural analysis. Furthermore, based on a multibody system dynamic model, the dynamic responses to WT were analysed. The results show that the impacts of WT were the strongest on the head car. WT had a strong effect on the train due to the unreasonable structural shape and the insufficient height of the windbreak in the transition region. This led to a strong push effect on the train; subsequently, the train’s dynamic characteristics deteriorated.

Recently, sodium-ion batteries have shown great potential for energy storage owing to their favorable electrochemical properties and intrinsic cost performance, which fuels the research and development of Mn-based layered oxides as promising sodium-ion cathodes. However, the undesirable structural evolution and oxygen redox impose great challenge on the cycling stability and rate capability of such cathodes. In this work, it is reported that Fe and Al can effectively tailor the Na

Flexible strain sensors have shown great application value in wearable devices. In the past decades, researchers have spent numerous efforts on developing high-stretchability, excellent dynamic durability, and large linear working range flexible strain sensors and shaped a series of important research results. However, the viscoelasticity of the elastic polymer is always a big challenge to develop a flexible sensor. Here, to overcome this challenge, we developed a novel self-repairing carbon nanotubes/ethylene vinyl acetate (CNTs/EVA) fiber strain sensor prepared by embedding the CNTs on the surface of the swollen shape memory EVA fiber via the ultrasonic method. The CNTs/EVA fiber strain sensors responded with significant results, with high stretchability (190% strain), large linear working range (up to 88% strain), excellent dynamic durability (5000 cycles), and fast response speed (312 ms). In addition, the permanently damaged conductive network of the strain sensors, caused by the viscoelasticity of elastic polymer, can restore above the transforming temperature of the shape memory CNTs/EVA fiber. Moreover, the performance of the restored strain sensors was almost as same as that of the original strain sensors. Furthermore, human health monitoring tests show that the CNTs/EVA fiber has a broad application prospect for human health monitoring in wearable electronic devices.

Charged nanocellulose (NC) with a high aspect ratio (larger than 100) extracted from animal or bacterial cellulose and chemical cross-linked NC aerogels have great promising applicability in material science, but facile fabrication of such NC aerogels from plant cellulose by physical cross-linking still remains a major challenge. In this work, carboxylated cellulose nanofiber (CNF) with the highest aspect ratio of 144 was extracted from wasted ginger fibers by a simple one-step acid hydrolysis. Our approach could easily make the carboxylated CNF assemble into robust bulk aerogels with tunable densities and desirable shapes on a large scale (3D macropores to mesopores) by hydrogen bonds. Excitingly, these CNF aerogels had better compression mechanical properties (99.5 kPa at 80% strain) and high shape recovery. Moreover, the CNF aerogels had strong coagulation–flocculation ability (87.1%), removal efficiency of MB dye uptake (127.73 mg/g), and moderate Cu2+ absorption capacity (45.053 mg/g), which were due...

Barium titanate/graphene oxide/polyurethane (BTO@GO@PU) composite membranes for microwave absorption were designed and fabricated by mechanical-blending of BTO and GO in PU medium, followed by mold formation. The cross section morphology of the BTO@GO@PU membrane indicated that the BTO nanoparticles with 450 nm average diameter are successfully incorporated into the PU matrix. Mechanical tensile measurement showed that, as the amount of BTO nanoparticles increased from 5 wt% to 20 wt%, the elastic modulus of the corresponding membrane increased up to 23.0 MPa elongation with the elongation above 450 %. Microwave absorption property of the BTO@GO@PU membranes were evaluated by measuring its reflection loss in the frequency range of 0.1-18 GHz. With the addition of BTO up to 20 wt%, the maximum absorptivity of the composite reached up to 51 %. This is attributed to the dielectric loss of BTO nanoparticles.

The development of biocompatible nanocomposites for biomedical applications such as drug release has attracted increasing attention in recent years. In this work, electrospun membranes composed of polycaprolactone (PCL) and shellac were fabricated because PCL has favorable mechanical and biological properties, such as high biocompatibility and biodegradability. Meanwhile, shellac is biocompatible and non-toxic; as a result, the fabricated membranes are attractive for controlled drug delivery. Here, PCL/shellac/PCL nanofiber membranes were treated by ethanol vapor to improve their properties for use in drug delivery applications. Salicylic acid was loaded in the drug delivery system as a model drug, and three PCL/shellac/PCL membrane configurations were investigated. Ethanol vapor treatment increased the tensile strength, flexibility, and transparency of the membranes. Both the tensile strength and drug release properties of the membranes strongly depended on the ratio of PCL to shellac.

In this paper, electrically actuated shape memory composites were prepared by compounding shape memory polyurethane (SMPU) with conductive antimony-doped tin oxide/TiO2 (ATO/TiO2) whiskers. The resultant composites, ATO/TiO2/SMPU, can be activated by electric voltages because of heating Joule and enhancement of heating efficiency by the conductive network resulting from the overlaps of whiskers. In addition to conductivity, ATO/TiO2/SMPU composites featured lighter color than most electroactive shape memory composites, which exhibit black color due to the addition of carbon materials. The composites exhibited uniform electrical resistance and rapid heat transfer performances. When the composites with 50 wt% ATO/TiO2 whiskers were used in a switch electric circuit as the switch, the circuit can turn off within 30 s. ATO/TiO2 whiskers improved Young's moduli by at least 390% and recovery stresses by more than 250% compared with pristine SMPU. Although the recovery rates were unsatisfactory in the first test cycle, composites with 40 wt% ATO/TiO2 whiskers and 50 wt% ATO/TiO2 whiskers still showed recovery rates higher than 96% and 94% in the third cycle, respectively. Keywords: Electrical actuation, Shape memory composite, Switch, Electric circuit, Morphing performance

Divalent cations were known to alleviate salinity stress on anammox bacteria. Understanding the mechanism of reducing the salinity stress on anammox granules is essential for the application of the anammox process for saline wastewater treatment. In this study, the effect of Ca2+ and Mg2+ augmentation on the recovery of the activity of freshwater anammox granules affected by salinity stress was evaluated. At the condition of a salinity stress of 5 g NaCl/L, the specific anammox activity (SAA) of the granule decreased to 50% of that of the SAA without NaCl treatment. Augmentation of Ca2+ at the optimum concentration of 200 mg/L increased the SAA up to 78% of the original activity, while the augmentation of Mg2+ at the optimum concentration of 70 mg/L increased the SAA up to 71%. EPS production in the granules was increased by the augmentation of divalent cations compared with the granules affected by salinity stress. In the soluble EPS, the ratio of protein to polysaccharides was higher in the granules augmented by Ca2+ than with Mg2+, and the functional groups of the EPS differed from each other. The amount of Na+ sequestered in the soluble EPS was increased by the augmentation of divalent cations, which seems to contribute to the alleviation of salinity stress. Ca. Kuenenia-like anammox bacteria, which were known to be salinity stress-tolerant, were predominant in the granules and there was no significant difference in the microbial community of the granules by the salinity stress treatment. Our results suggest that the alleviation effect of the divalent cations on the salinity stress on the anammox granules might be associated with the increased production of different EPS rather than in changes to the anammox bacteria.

In this study, a new weaving technology with a modified heddle position system based on a self-built three-dimensional (3D) weaving loom is designed, and four typical 3D woven-structure textile groups are manufactured: layer-to-layer orthogonal weaving, through-thickness orthogonal weaving, layer-to-layer angle-interlock weaving, and through-thickness angle-interlock weaving. The new weaving technology has great potential for manufacturing various 3D woven structures effectively and efficiently. The fabricated 3D woven textile-reinforced epoxy-resin composites undergo quasi-static three-point bending tests to study the influence of the woven structure on the flexural performance and failure modes along the textile warp and weft directions. The composites along the weft direction (weft-direction beams) have a larger flexural modulus but smaller failure strain compared with the warp direction (warp-direction beams) for all woven-structure types. Among the designed 3D textile composites, the angle-interlock woven structures have a larger flexural strength (50%), modulus (40%), and failure resistance than have the orthogonal-woven structures. Overall, the through-thickness angle-interlock woven structure has the best flexural-failure resistance among all textile structures, and is the optimal structural design based on this modified weaving technology.

It is known that scaffold is a key factor in bone tissue engineering. The aim of this study was to improve the design of scaffold in order to achieve an effect of precisely matching the irregular boundaries of bone defects as well as facilitate clinical application. In this study, controllable three-dimensional porous shape memory polyurethane/nano-hydroxyapatite composite scaffolds were successfully fabricated. Detailed studies were performed to evaluate its structure, porosities, and mechanical properties, emphasizing the effect of different apertures of scaffolds on shape recovery behaviors and biological performance in vitro. Results showed its compression recovery ratios and shape recovery ratios of all scaffolds could reach more than 99 and 90%, respectively, which could let it more accurately match the irregular boundaries of bone defects. And also its cell proliferation ability was improved with the increase in the apertures. Thus, these scaffolds have potential applications for the bone tissue engineering.

The traditional approach toward improving the crystallization rate as well as the mechanical and barrier properties of poly(lactic acid) (PLA) is the incorporation of nanocelluloses (NCs). Unfortunately, little study has been focused on the influence of the differences in NC morphology and dimensions on the PLA property enhancement. Here, by HCOOH/HCl hydrolysis of lyocell fibers, microcrystalline cellulose (MCC), and ginger fibers, we unveil the preparation of cellulose nanospheres (CNS), rod-like cellulose nanocrystals (CNC), and cellulose nanofibers (CNF) with different aspect ratios, respectively. All the NC surfaces were chemically modified by Fischer esterification with hydrophobic formate groups to improve the NC dispersion in the PLA matrix. This study systematically compared CNS, CNC, and CNF as reinforcing agents to induce different kinds of heterogeneous nucleation and reinforce the effects on the properties of PLA. The incorporation of three NCs can greatly improve the PLA crystallization ability, thermal stability, and mechanical strength of nanocomposites. At the same NC loading level, the PLA/CNS showed the highest crystallinity (19.8 ± 0.4%) with a smaller spherulite size (33 ± 1.5 μm), indicating that CNS, with its high specific surface area, can induce a stronger heterogeneous nucleation effect on the PLA crystallization than CNC or CNF. Instead, compared to PLA, the PLA/CNF nanocomposites gave the largest Young's modulus increase of 350 %, due to the larger aspect ratio/rigidity of CNF and their interlocking or percolation network caused by filler-matrix interfacial bonds. Furthermore, taking these factors of hydrogen bonding interaction, increased crystallinity, and interfacial tortuosity into account, the PLA/CNC nanocomposite films showed the best barrier property against water vapor and lowest migration levels in two liquid food simulates (well below 60 mg kg-1 for required overall migration in packaging) than CNS- and CNF-based films. This comparative study was very beneficial for selecting reasonable nanocelluloses as nucleation/reinforcing agents in robust-barrier packaging biomaterials with outstanding mechanical and thermal performance.

Hollow silica spheres (HSS) have attracted considerable attention in recent years because of their unique physical and chemical properties, as well as can be used for wide range potential applications. In this study, a novel HSS was successfully synthesized via silica sol self-templated route and vacuum freeze-drying assistant method. The experimental results revealed that the HSS exhibited bowl-like and deflated balloon-like morphology structure and thin sphere shell was approximately 30 nm. The particle size of the HSS was almost between 0.20 and 2.50 µm. The possible mechanism for the formation of the HHS was discussed and proposed.

Silk fibroin (SF) powder was prepared by a nontoxic low-sodium system to avoid introducing massive unwanted chemicals during the SF hydrolysis process. In this study, water-soluble and water-insoluble SF powder, were obtained through lyophilised SF solution by boiling degummed silk fiber in low-concentration Na 2 CO 3 solution with a certain degree of pressure. Compared with traditional SF hydrolysis systems, this study provides a simple and potentially time-saving approach to produce SF powder at a low cost.

A new design of cathode current-collecting element (CCCE) based on Sm0.5Sr0.5CoO3, which contains gas channels and an array of truncated-pyramid-shaped contact tips, is synthesized through die pressing followed by a conventional solid-state reaction for intermediate-temperature solid oxide fuel cells (IT-SOFCs). This configuration could not only maintain the high electronic conductivity of the material to ensure the efficiency of current collecting, but also improve the gas diffusion rate at the cathode side. The height h of the channel tips on the CCCEs reaches approximately 60, 120, and 240 μm, respectively, which results in the variation in polarization resistance (R P) more significantly than the contact area of the tips does. The experiments show that the R P of the symmetric cells decreased from 0.267 to 0.060 Ω cm2 at 800 °C after employing the CCCE with modified parameters. In addition, the measured peak power density of the individual cell is enhanced from 111 to 145 mW cm−2 at 800 °C. The results show that the cathode current-collecting elements may be potentially useful for applications in IT-SOFCs.

ZnFe2O4/SnO2 semiconductor nanocomposites with various mole ratios were prepared by a simple chemical synthesis process that based on sol–gel method. The structural properties were determined by X-ray diffraction and scanning electron microscope technique. The XRD study reveals that no impurity phase, such as ZnO, Fe2O3, existed in all the samples. The average grain size was found to be about 39.51 nm when the mole ratio of ZnFe2O4/SnO2 is 2:1 (Z2S1), which is benefit for improving gas sensing property. The Z2S1 sample showed a relatively higher response (11.46) at a lower working temperature (176 °C) to acetone compared with other composites, and the response/recovery time were both very short. The improving gas sensing properties may be due to the fine grain and the formation of the ZnFe2O4/SnO2 heterojunction structure.

In the present study, a finite element impact model was created and analyzed by commercial FEM code ANSYS®-AUTODYN and then validated by drop weight impact experiment. Moreover, models of single- and multilayer panels of plain weave as well as different weaving architectures were designed and created with and without holes to compare impact properties. The influence of the size and location of hole defect on the impact behavior of single-layer Twaron®fabric were investigated, the degree of influence of hole defects with different sizes on the impact behavior and the influence level by different location of the hole defects were well investigated in. In addition, the effect of hole defects on the impact behavior of multi-layer armor panel were studied. Hole defects were less influential in terms of impact contact force and had less severe constraining effect on front layer of the panel when the number of multi-layer armor panels increased. Furthermore, the effect of hole defects on the impact behavior of different weaving architectures (i.e. plain, twill, basket, and satin weave) were analyzed. Plain weave fabric had the highest energy absorption capability in impact scenarios with and without holes among all the woven architectures. Plain weave fabric was the most affected and twill weave was the least affected by hole defects in terms of transverse wave velocity; the satin weave was the most affected and the twill weave was the least affected by hole defects in terms of energy absorption. These findings will provide guidance for engineering of soft body amour and composite materials.

Understanding the Zn diffusion behavior in GaSb is very important to accurately control the distribution of Zn during the fabrication of photoelectric devices. The surface concentration and effective surface diffusivity are two key parameters for modeling the Zn profile in GaSb. The experimental results indicated that when the diffusion temperature and time are kept unchanged, the diffusion profiles with pure Zn, Zn–Sb, and Zn–Ga sources differ in the surface concentration and effective surface diffusivity. To quantitatively explain the effects of source composition on the two parameters, the relationship between the two parameters and the vapor pressure surrounding the GaSb wafer in the diffusion process was deduced based on a surface-equilibrium assumption and the substitutional-interstitial mechanism. The Ga/Sb/Zn ternary phase diagram was calculated and discussed for determining the vapor pressures in different source cases. The ratio of surface concentrations and that of effective surface diffusivities between different sources were obtained to quantitatively explain the experiment results. The theoretical and experimental results both indicated that adding Sb to pure Zn source keeps the surface concentration unchanged while slightly decreases the effective surface diffusivity, and that adding Ga to pure Zn source significantly decreases both the surface concentration and effective surface diffusivity.

Perfect graphene sheets are zero-gap semiconductors (semi-metals) with extremely high electron mobility and have considerable potential in electronics and optics, high sensitivity sensors, supercapacitors and biodevices. Practically applying the semiconductor properties of graphene has become the focus of research. We prepared a microscopically ordered graphene oxide fiber by liquid crystal spinning. The high concentration (50 mg ml−1) graphene oxide dispersion is favorable for forming highly ordered nematic phase in the spinning process. In a liquid crystal, graphene inside a fiber has an ordered regular structure arranged in parallel along the axial direction. High-strength (432.6 ± 12.7 MPa) and highly conductive (4.9 × 104 S/m) graphene fibers are obtained by chemical reduction, in which a strong π-π bonds forms between parallel graphene layers. Given that strain can change graphene band gap and affect electron transport, it is inherited to the graphene fiber, which is macroscopically conductive. Variations, strain response sensors made from this graphene fiber with high sensitivity, and strain range (2%–8%) can be used in the detection of body health signals (speech and pulse waves). These parameters have potential use in artificial electronics skin and wearable health detection.

To improve the efficiency during the process of Mg2+/Li+ separation, a novel nanofiltration (NF) membrane was optimized by doping graphene oxide (GO) additives into the ultrafiltration (UF) base membrane. The effects of GO doping content on the morphology, structure and surface properties of UF membrane and the final NF membrane were studied comprehensively. The hydrophilic GO acted as a “bridge” between UF membrane and polyamide layer due to the “anchor effect”, which significantly enhanced the interaction between base membrane and polyamide layer. The results revealed that with ultra-low GO doping content of 0.05 wt%, the final NF005 membrane exhibited a high selective separation capacity for Mg2+ and Li+ (SMg,Li≈0.062), and the flux increased by about 119% compared with the pure NF0 membrane. Additionally, due to the high stability of membrane, the excellent separation capacity of NF005 membrane only changed slightly after 7-day cycle filtration test. Importantly, a small amount of GO doping greatly improved the permeability of both UF and NF membranes, which correspondingly improved the separation efficiency and accelerated the filtration rate. This work provides a new direction for designing membrane with high efficiency for Mg2+/Li+ separation, which is potential in the field of lithium extraction.

This work studies the optical reflectance of nanoporous gold (NPG) thin films of varying pore volume fraction (PVF) synthesized by chemical dealloying of Ag-Au alloy precursors. The fabricated samples are characterized by scanning electron microscopy, and spectral hemispherical reflectance is measured with an integrating sphere. The effective isotropic optical constants of NPG with varying PVF are modeled for the wavelength range from 0.4 to 1.6 μm using the Bruggeman effective medium theory. As the thickness of the NPG thin films is more than ten times larger than the effective penetration depth, the spectral reflectance is simply modeled with the Fresnel coefficients at the interface of air and semi-infinite NPG with different incident angles and polarizations. Consistent with the modeling results, the optical measurement data shows that the spectral normal reflectance of NPG significantly decreases with larger PVF values in the near-infrared regime. On the other hand, the reflectance increases greatly only within visible range at larger oblique angles for transverse-electric polarized waves compared to transverse-magnetic waves. Moreover, the NPG samples demonstrate good thermal stability from room temperature up to 100 °C with little changes in the temperature-dependent spectral hemispherical reflectance.

Vapor-grown carbon fiber (VGCF)-based polyurethane foam (VGCF@PUF) was fabricated by H2O–N, N-dimethyl formamide (DMF) solvent exchange for compaction-adjustable high-performance microwave shielding. VGCF@PUF specimens with different thicknesses were obtained by compression molding at 120 °C and 0–20 MPa. Tensile tests indicated that the hot compression enhanced both the mechanical strength and elongation of the VGCF@PUF. Moreover, with increasing compression, the electrical conductivity (σ) of the VGCF@PUF was improved by orders of magnitude. This indicated that the effective inter-connection of VGCFs achieved by hot compression is vital for enhancing the electrical conductivity of the VGCF@PUF. As for the microwave shielding, the results showed that increasing compression greatly improved the microwave shielding performance of the VGCF@PUF. For example, the VGCF@PUF specimen with approximately 25 wt% VGCF, which had thicknesses of 1.96 mm and 0.45 mm before and after hot-compression, respectively, revealed a change in shielding effectiveness (SE) from 10-15 dB to 35–50 dB. This is because the hot compression was considered to efficiently improve the electrical inter-connection of the nanoscale carbon nanofibers in the VGCF@PUF. This research demonstrated that the structure optimization of shielding materials is of great importance for improvement of electrical conductivity and microwave shielding performance.

Two-way reversible shape memory polymer foams with porous three-dimensional structures were prepared using salt-leaching technology based on benzoyl peroxide (BPO) thermo-crosslinked poly(ethylene-co-vinyl acetate) (PEVA). Various pore sizes of PEVA/BPO porous foam were obtained using different NaCl particle sizes. The PEVA/BPO foams with various pore sizes exhibited reversible shape changes that allowed contraction during cooling and expansion during heating. The ideal two-way shape memory performance can be clearly observed in the large pore size sample PEVA/BPO-450. The morphology was characterized by scanning electron micron microscopy (SEM) and X-ray microcomputed tomography scanning (μCT) analysis. The compression behavior of PEVA/BPO foam was also investigated. These properties of two-way reversible shape memory PEVA/BPO foams could qualify their use as lightweight porous actuators in artificial intelligence and aerospace applications.

We synthesized two-way (reversible) chemically crosslinked semi-crystalline shape memory polymers with various crosslinking densities from poly(ethylene-co-vinyl acetate) (PEVA) with various contents of benzoyl peroxide (BPO). The developed materials were capable of reversible shape change, and we ensured that the “switch on” temperature, which triggers shape change, was within a reasonable range. Each PEVA-B10 (PEVA with 10 wt% BPO) sample had optimal actuation performance and an excellent recovery ratio of over 99%. The BPO crosslinker played an important role in allowing the samples to return to their original shape, and the samples (PEVA/BPO soft materials) with high crosslinking densities had significantly improved recovery ratios. As a result, the developed PEVA/BPO materials were adequately soft and had good mechanical properties, even at large deformation. Therefore, the materials are potentially useful as soft material actuators, or for other applications.

Poly(ethylene terephthalate) (PET) fabric-reinforced polyvinyl chloride (PVC) composites have a wide range of applications, but the interface bonding of PET fabric/PVC composites has remained a challenge. In this work, a new in-situ SiO2/tributyl citrate sizing agent was synthesized according to the principle of &ldquo, similar compatibility.&rdquo, The developed sizing agent was used as a PET surface modifier to enhance the interfacial performance of PET fabric/PVC composites. The morphology and structure of the PET filaments, the wettability and tensile properties of the PET fabric, the interfacial adhesion, and the tensile and tearing properties of the PET fabric/PVC composites were investigated. Experimental results showed that many SiO2 nanoparticles were scattered on the surface of the modified PET filaments. Moreover, the surface roughness of the modified PET filaments remarkably increased in comparison with that of the untreated PET filaments. The contact angle of the modified PET filaments was also smaller than that of the untreated ones. The peeling strength of the modified PET fabrics/PVC composites was 0.663 N/mm, which increased by 62.50% in comparison with the peeling strength of the untreated ones (0.408 N/mm). This work provides a new approach to the surface modification of PET and improves the properties of PET fabric/PVC composites.