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(1-x)BiScO3-xPbTiO3 (BS-PT) ceramics have excellent piezoelectricity and high Curie temperature at its morphotropic phase boundary (x=0.64), so it is a promising piezoelectric material for fabricating high temperature ultrasonic transducer (HTUT). Electric properties of 0.36BS-0.64PT ceramics were characterized at different temperature, and a HTUT with the center frequency of about 15 MHz was designed by PiezoCAD based on the measuring results. The prepared HTUT was tested in a silicone oil bath at different temperature systematically. The test results show that the HTUT can maintain a stable electrical resonance until 290 °C, and get a clear echo response until 250 °C with slight changes of the center frequency. Then a stepped metal block submerged in silicone oil was imaged by the HTUT until 250 °C. Velocity of silicone oil and axial resolution of the HTUT at different temperature were calculated. The results verify the capability of 0.36BS-0.64PT based HTUT for high temperature ultrasonic imaging applications.

Over the past few years, semiconductor materials (especially bismuth tungstate) exhibiting unique environment purification and energy conversion capacities arouse huge attention as impacted by issues of environmental pollution and energy shortage, whereas its application is restricted by the problems of high carrier recombination rate and unsatisfactory degradation efficiency. In this study, Eu:Bi2WO6 nanostructures containing Eu ions of different concentrations were synthesized with a chemical solution method, and CdS was generated on the surface of Eu:Bi2WO6 nanostructures in situ epitaxial to synthesize the Eu:Bi2WO6/CdS composites. The effects of Eu doping concentration on the crystal structure, chemical composition, local structure, optical properties and visible-light photocatalytic properties exhibited by Eu:Bi2WO6/CdS nanostructures were studied more specifically, and the Eu doping behavior on the improvement mechanisms for optical and photocatalytic performance exhibited by Eu:Bi2WO6/CdS nanostructures was clarified. The robust PL emission peak at about 390 nm and weak emission peak at nearly 450 nm are attributed to the exciton emission and defect state of Bi2WO6/CdS nanostructure, respectively. As indicated from the mechanism insights, the reasonable introduction of Eu3+ could alter the band gap of the photocatalyst, and the epitaxial CdS could decrease the recombination probability of electron and hole in the Bi2WO6/CdS, while improving the photocatalytic activity. This study supplies new occasions for rational excogitation and better comprehending of atomic-scale complicated structures for applications in numerous fields (e.g., energy and environmental protection).

Herein, we demonstrate a tetradic double-network physical cross-linking hydrogel comprising of gelatin, polyacrylic acid, tannic acid, and aluminum chloride as wearable hydrogel sensors. Based on the coordination bonds, hydrogen bonds, and chain entanglements of the two networks, the acquired hydrogel possesses excellent tensile properties, self-healing performance, and adhesiveness to many substrates. Mechanical properties can be tuned with fracture strain ranging from 900 to 2200% and tensile strength ranging from 24 to 216 kPa, respectively. Besides, the hydrogel also exhibits good strain-sensitivity when monitoring the motions of humans, such as bending of fingers, bending of elbows. Hence, we can believe that the GATA hydrogel has numerous applications in soft robots, intelligent wearable devices, and human health supervision.

Zinc oxide nanoparticles (ZnO NPs) were synthesized using Zinc Nitrate as precursor salt, and plant leaves extracts from Azadirachta indica (Common name: Neem), Cymbopogan citratus (Common name: Lemongrass), and Mangifera indica (Common name: Mango), as both chelating and reducing agents for the synthesis of ZnO NPs by a simple cost-effective and eco-friendly green method. The biosynthesized ZnO NPs were well characterized by various methods. XRD pattern revealed a hexagonal wurtzite phase of ZnO, with no other impurity peaks present revealing XRD crystalline sizes of 13.94-16.37 nm calculated using Scherrer equation. The XPS confirmed the presence of Zn, O, and C, and the carbon peaks are almost in agreement with peaks observed by FT-IR. TEM showed the different ZnO with spherical shapes and some aggregations. BET surface area gave 24.98, 21.62, and 22.72 m2/g, respectively for ZnO-AI, ZnO-Cyc, and ZnO-MI, while BJH pore volume and average pore diameter were estimated to be 0.217 cc/g, 0.209 cc/g, 0.211 cc/g, and 2.132 nm, 2.025 nm, and 2.100 nm respectively for ZnO-AI, ZnO-Cyc, and ZnO-MI.Furthermore, the bio-synthesized ZnO NPs were evaluated for their catalytic and photocatalytic performance in the degradation of aqueous tetracycline (TC). The biosynthesized ZnO NPs exhibit good photodegradation efficiency for TC in varying degrees with ZnO-AI > ZnO-MI > ZnO-Cyc. Optimum operational parameters for TC degradation using the ZnO-AI were established, and maximum degradation efficiency of 84.8% was obtained. In addition, the catalyst can also be regenerated and reused up to three cycles, with the third cycle still achieving greater than 80% TC degradation.

Owing to the improved thermophysical properties of nano-materials, the nanofluid convey novel applications in industries, engineering as well as bio-medicals. With high efficiency performances, the nanoparticles include applications in various cooling and heating systems, energy production, aerospace engineering, thermal extrusion, bio-medical applications like treatment of diseases, brain tumour, surgical applications and many more. Moreover, the magneto-nanofluids have the characteristics in the flow of blood in the human artery. The current analysis deals with the free convective unsteady flow of viscous nanofluid subject to the magnetic force over a vertical plate in presence of porous space. The heat transfer phenomenon is accessed by utilizing the additional features like Joule heating, viscous dissipation and absorption coefficients. In addition to the volume fraction of the nanofluid, the effect of the chemical reaction is also introduced. The solution procedure for the modified time-dependent boundary value problem is performed by using the code in-build MATLAB namely Built-in-Shooting method. The change in velocity, temperature and concentration of nano-materials is examined through various graphs. The physical consequences of flow parameters like porosity parameter K p 1 ⩽ K p ⩽ 3 , thermal Grashoff number Gr 1 ⩽ G r ⩽ 3 , solutal Grashoff number Gc 1 ⩽ G c ⩽ 3 , magnetic field parameter M 1 ⩽ M ⩽ 3 , thermal radiation parameter Nr 0.1 ⩽ N r ⩽ 1 , radiation absorption parameter Q 0 ⩽ Q ⩽ 0.5 , Prandtl number Pr 2 ⩽ Pr ⩽ 21 , Eckert number Ec 0 ⩽ E c ⩽ 0.4 , heat source S - 0.2 ⩽ S ⩽ 0.2 , chemical reaction parameter Kc 1 ⩽ K c ⩽ 4 , nanoparticles volume fraction ϕ 0.0 ⩽ ϕ ⩽ 0.1 , Lewis number Le 1 ⩽ L e ⩽ 10 on velocity, temperature and concentration distributions is graphically analyzed. The results show that skin friction coefficients decline with buoyant forces. A lower numerical variation in Nusselt number is resulted with heat source parameter. Moreover, a sharp fall in nanofluid concentration is noticed with increment of chemical reactants and Lewis number.

The developing interest in thermal engineering and nano-technology presented the idea of nanoparticles with enhanced thermal mechanisms and attained convinced novel applications in heat transportation systems, solar energy, micromechanics, air conditioning systems, cooling and heating facilities, bio-medical applications like cancer treatment, artificial heart surgery etc. Beside this, the phenomenon of entropy generation is another fascinating research area which used to improve the assessment of heat transportation with optimized procedure. The entropy generation in bio-convective flow of Eyring-Powell nanofluid over permeable stretched surface of cylinder is scrutinized in this research. The effects of magnetic field, thermal radiation and viscous dissipation are considered. Concentration communication is obtained in view of activation energy associated with binary chemical reaction. Furthermore, properties of Brownian diffusion and thermophoresis of nanoparticles are accounted. Suspended nanoparticles are made stable through mutual effects of bioconvection and buoyancy forces. Total entropy generation rate is modeled through second thermodynamics law. The governing flow model is obtained with the help of boundary layer approximations. Dimensional model is transformed into non-dimensional one by transformations and then tackled by Newton built-in shooting procedure. Impact of different influential variables on entropy generation, velocity, temperature, concentration, Bejan number and motile density of microorganisms are analyzed via graphs. Numerical values of skin friction coefficient, density, Sherwood and Nusselt numbers are tabulated and examined. Major findings are listed at the end. Since this analysis is based on theoretical flow assumptions, therefore the flow parameters specify the constant range like 0.0 ⩽ Γ ⩽ 6.0 , 1.0 ⩽ γ ⩽ 4.0 , 0.1 ⩽ H a ⩽ 1.2 , 0.2 ⩽ λ ⩽ 0.6 , 0.2 ⩽ R d ⩽ 1.7 , 0.1 ⩽ K ⩽ 3.0 , 0.1 ⩽ Pr ⩽ 4.5 , 0.3 ⩽ N b ⩽ 1.8 , 0.2 ⩽ N t ⩽ 1.7 , 0.0 ⩽ E 1 ⩽ 1.0 , 1.0 ⩽ E c ⩽ 4.0 , 0.2 ⩽ σ ⩽ 1.4 , 0.4 ⩽ S c ⩽ 1.7 , 1.0 ⩽ δ ⩽ 2.5 , 0.5 ⩽ P e ⩽ 2.0 , 0.5 ⩽ Ω ° ⩽ 2.0 , 0.1 ⩽ B r ⩽ 1.0 , 0.1 ⩽ L b ⩽ 1.5 . The results show that fluid velocity decreases with curvature parameter and porosity constant. A decreasing variation in nanofluid temperature due to curvature parameter is examined. The entropy generation and Bejan number decline Brinkman number, motile density diffusion parameter and mass concentration diffusion variable. Furthermore, it is observed that skin friction coefficient increases with curvature parameter and porosity constant.

The ordered membrane electrode assembly (MEA) is currently the frontier research field of proton exchange membrane fuel cells (PEMFCs). The ordered MEA is effective in increasing the utilization of...

High-temperature proton exchange membrane fuel cells (HT-PEMFCs) bring new opportunities for portable power generation due to their outstanding advantages such as high tolerance to fuel/air impurities and simplified heat/water management. However, carbon-supported nanostructured Pt-based catalysts running at temperatures over 150°C are challenged by the severe aggregation and carbon corrosion, thus leading to poor durability. Herein, we demonstrate that dendritic Pt-Ni nanoparticles supported on fluorinated carbon black (white carbon black) could significantly enhance the performance and durability of HT-PEMFCs as the cathode catalysts running at 160°C due to the strong interaction of the F and Ni atoms to form a NixFy interface on Pt-Ni nanoparticles. With the formation of a stable NixFy interface, this integrated HT-PEMFC reached peak power densities of 906 mW cm−2 and demonstrated excellent durability at 160°C under anhydrous H2/O2 conditions. This mitigation strategy was applied to Pt-alloy/C electrocatalysts and resulted in the elimination of Pt dissolution in practical fuel cells.

BACKGROUND OBJECTIVES Newly developed in vivo skin and skull optical clearing techniques can greatly improve the optical imaging performance, showing great advantages and clinical prospects. However, there is a poor understanding of in vivo optical clearing-induced changes in the skin and skull. MATERIALS AND METHODS Here, we employed in vivo skin/skull optical clearing techniques to improve the optical coherence tomography (OCT) imaging quality. And we also used polarization-sensitive OCT to monitor the dynamic changes in the polarization characteristics of the skin and skull during in vivo optical clearing processes. Two-photon imaging was used to evaluate changes in tissue barrier function and structure. Additionally, Raman spectra were employed for assessing the changes of each component in the skin and skull before and after optical clearing treatment. RESULTS The results indicated that the polarization states of the skin and skull were altered with the usages of optical clearing agents. And the barrier permeability and collagen fiber distribution of them became disordered. Furthermore, the Raman spectra of tissue demonstrated that the applications of in vivo tissue optical clearing methods could lead to the reduction of proteins, lipids, and inorganic salts in these two organs. Interestingly, after recovery treatment, the structure and function of the skin and skull could almost recover to the initial states. CONCLUSION In vivo tissue optical clearing can lead to changes in the structure and function of tissue, which was reversible to some extent. This study plays an important role in revealing the underlying mechanisms of tissue optical clearing techniques; moreover, it is conducive to the development and optimization of a novel in vivo tissue optical clearing approaches in future.

The instability of pressurized dense gas-solid jets in a two-dimensional nozzle is experimentally studied using a high-speed camera, and the effects of the hopper pressure and the particle diameter on instability are considered. As particle velocity rises with hopper pressure, dense gas-solid jets become unstable and display an asymmetric oscillation, which is quasi-periodic and its frequency and evolution are further characterized. For particle diameters of d = 185 μm and 410 μm, the time-average frequencies increase linearly with the exit particle velocities. The asymmetric structures grow along the nozzle, and even undergo deformation and merging. The macroshot of the flow transition region between hopper and nozzle indicates that gas-solid separation generates fluctuations which will propagate both upstream and downstream. In the nozzle, fluctuations are amplified by the enhanced gas-solid interaction, evolving to the asymmetric structures.

Afterglow materials have become one of the most promising luminescent materials due to their long luminescence lifetime. Photoluminescence quantum yield (PLQY), as one of the most fundamental and essential parameters of luminescent materials, can directly evaluate the luminescence properties of emissive compounds. Recently, a type of afterglow material based on a photochemical reaction has been developed. However, there is no suitable method to measure the PLQY of these afterglow materials due to their special luminescence principle. Herein, we present a method to measure the PLQY for these afterglow materials by collecting the luminescent dynamic curves of emission and excitation light at specific wavelength regions using a commercial spectrometer and an integrating sphere. We found that the emitted photons of this kind of afterglow material are in direct proportion to the excitation time, which means the PLQY is irrelevant to the excitation time.

Solid polymer electrolytes (SPEs), with improved energy densities and operational safety, have replaced liquid electrolytes in next-generation Li metal batteries (LMBs). However, the detrimental ef...

In order to obtain an ultrasonic transducer (UT) with ultra-broad bandwidth (BW), a multilayer stairstep piezoelectric structure (MSPS) is designed and fabricated. Based on the theoretical computation, the relationship between the resonant frequency and thickness of the piezoelectric layer is obtained. The designed MSPS includes 15 layers from center to side, and its frequency range is 5–22 MHz. The finite element method (FEM) based PZFlex software is used to predict the performance of UT with the designed MSPS, and the thickness of each layer is optimized according to the simulation results to achieve the ultra-broad-BW UT. The UT with the designed MSPS is fabricated and systematically characterized. The measured results show that the fabricated UT has a center frequency of 10.54 MHz and a −6 dB BW of 121%, which agree well with the simulation results (11.75 MHz and 140%). The MSPS has significant potential in UT applications.

Novel organic–inorganic layer-by-layer (LbL) multilayers for visible-light phototropy, comprised of polyvinylpyrrolidone (PVP) and phosphomolybdic acid (PMoA), were fabricated via layer-by-layer (LbL) assembly with ultrasonic pretreatment. The characterizations revealed that the Keggin spatial geometry of the PMoA was still maintained in the final ultrasonic-assisted LbL thin films, which promoted halogenesis between the PVP and PMoA. Intriguingly, instead of destroying the PVP thin film, the ultrasonic pretreatment process successfully dispersed the PMoA in the PVP thin film with a median size of approximately 3.6 nm. Thanks to the dispersion of the PMoA particles, the photochromic capabilities of the ultrasonic-assisted PVP/PMoA LbL thin films gained remarkable improvement. Moreover, decreasing the size of the PMoA particles to quantum dots (10–3.4 nm) induces an up-conversion and dielectric confinement effect, which increases the intensity of the absorption peak (0.235 increased to 0.45) while narrowing the emission energy (2.51 eV narrowed to 2.23 eV). At the same time, the size reduction also extended the range of the absorption wavelength, increases the characteristic absorption intensity, and accelerates the coloration rate over the same illumination period.

It is a challenge to reduce the dielectric loss and increase the tunability of pure barium strontium titanate (BST) films for microwave tunable application because these two properties change simultaneously. Herein, a novel composite of strontium titanate (ST) and potassium-doped BST (KBST) has been designed as ST/KBST/ST sandwich-type film with various ST and KBST layers. X-ray diffraction patterns show that the film exhibits cubic perovskite polycrystalline structure composed of BST and ST phase, mainly grow along (110) crystal plane with average grain size of less than 20 nm and decreasing BST phase/ST phase ratio with increasing film thickness. Scanning electron microscope shows that no interfacial layer can be observed, indicating that ST and KBST are fully compounded. Low dielectric loss and high tunability at -10 – 10 V and stable and excellent dielectric properties at 1 GHz are achieved, meeting the needs of microwave tunable application at high frequency. The surface structures are also studied by other analysis methods, and ST/MgBST/ST sandwich-type film is compared.

This contemporary study is done to analyze the comparative study of hybrid nanofluids motion due to semi-infinite asymmetric channel with contracting and expanding porous walls orthogonally. Boundary conditions considered are convective conditions. Hybrid nanofluids consist of more than two nanoparticles. Purpose of nanofluid is to enhance the heat transfer characteristics by adding nanoparticles into base fluid. When we add two nanoparticles collectively to form nanofluid than it is more useful. Maganese Zinc ferrite and Nickle Zinc ferrite are used as nanoparticles and engine oil and Kerosene oil are considered in place of base fluid. Nonlinear heat source sink effect is considered along with activation energy. Darcy Forchheimer porous medium is considered in momentum equation. We have introduces suitable transformations to get ODE’s from PDE’s. Homotopy analysis method is used to find the convergent solution. For more accuracy tables are also drawn for convergent solution. Velocity for M n Z n F e 2 O 4 - N i Z n F e 2 O 4 - C 10 H 22 - C 8 H 18 is lowest among all. Impact of important parameters along velocity, temperature, concentration, skin friction and Nusselt number is seen through graphs. For positive values of wall contraction (or expansion) rate parameter velocity of the fluid enhances. Motion slows down for greater Forchheimer number. Temperature rises via thermal Biot number. Concentration profile is increasing with larger estimation of activation energy.

Benefiting from high flexibility and weavability, the wire-shaped supercapacitors (SCs) arouse tremendous interests for the applications in wearable/portable electronics. Graphene fiber (GF) is considered as a promising linear electrode for wire-shaped SCs. However, the bottleneck is how to develop the GF-based linear electrode with facile fabrication process while well-maintaining satisfactory electrochemical performance. Herein, a novel Fe3O4@GF composite linear electrode is proposed via a chemical reduction-induced assembly approach, in which the GO and Fe3O4 nanoparticles (NPs) realize the efficient self-assembly owing to the electrostatic and van der Waals interactions, as well as the sufficient reduction of GO during the preparation process. The resultant fiber-shaped architecture shows boosted charge-transfer kinetics, high flexibility and structural integrity. Such Fe3O4@GF linear electrode exhibits excellent electrochemical behaviors including a large volumetric specific capacitance (∼250.75 F cm−3), remarkable rate capability and favorable electrochemical kinetics in aqueous electrolyte, superior than previously reported GF-based linear electrodes. For real application, a high-performance wire-shaped SC with excellent flexibility and weavability is fabricated based on such Fe3O4@GF linear electrode and gel electrolyte, demonstrating ultrahigh volumetric energy density (18.8 mWh cm−3), power density (4000 mW cm−3) and strong durability (∼93.5% retention after 10000 cycles). Prospectively, the fabricated wire-shaped SC can maintain reliable electrochemical behaviors in various deformation states, showing its potentials in future portable and wearable devices.

All-solid-state lithium batteries (ASSLBs) are regarded as the next-generation energy storage devices due to their superior safety and potential high energy density. In ASSLBs, a composite solid electrolyte is the most competitive candidate. The interface between the cathode and composite electrolyte and the interface between ceramic and polymers are important factors affecting the performance of solid-state batteries. The interface between the superionic conductor and polymer electrolyte (polyvinylidene fluoride) was modified by in situ synthesis of a pyrochlore-type La2Sn2O7 (LSO) ceramic layer on the surface of Li6.4La3Zr1.4Ta0.6O12 (LLZTO). The synthesis of LSO consumes La in LLZTO, increases the concentration of lithium ions in LLZTO, and significantly improves the conductivity of the composite electrolyte (LLZTO@LSO-CSE). Compared with the pristine sample (3.15 × 10-5 S cm-1), the conductivity of LLZTO@0.9%LSO-CSE was improved by an order of magnitude (as high as 1.30 × 10-4 S cm-1). At the same time, the lithium-ion transference number of LLZTO@0.9%LSO-CSE and LLZTO@1.5%LSO-CSE was 0.42 and 0.44, respectively (LLZTO@0%LSO-CSE was 0.36). Meanwhile, the pyrochlore structure of LSO has the characteristics of fast energy storage and conversion, so the full cell LiFePO4|LLZTO@LSO-CSE|Li showed superior rate capability and cycling stability. As anticipated, the discharge capacities of LiFePO4|LLZTO@0.9%LSO-CSE|Li were 141.4 mA h g-1 (1 C) and 128.1 mA h g-1 (2 C), respectively. However, the discharge capacities of pristine batteries without LLZTO modification were 122.5 mA h g-1 (1 C) and 88.7 mA h g-1 (2 C). After 400 cycles, the discharge capacity of the LiFePO4|LLZTO@0.9%LSO-CSE|Li remained at 110.6 mA h g-1, the Coulomb efficiency was 99.4%, and the capacity retention rate was 72% compared to 75.5 mA h g-1, 98, and 49% for the pristine one, respectively. In addition, the transfer printing (TP) technology was used to improve the interface between the cathode and the solid-state electrolyte, which immensely increased the energy density (without aluminum foil). Compared with the original interface impedance of 379 Ω, the interface impedance was significantly reduced to 213 Ω. This uniquely developed LLZTO@LSO-CSE combined with the TP technology can provide an effective approach for the development of all-solid-state batteries.

As the global energy policy gradually shifts from fossil energy to renewable energy, lithium batteries, as important energy storage devices, have a great advantage over other batteries and have attracted widespread attention. With the increasing energy density of lithium batteries, promotion of their safety is urgent. Thermal runaway is an inevitable safety problem in lithium battery research. Therefore, paying attention to the thermal hazards of lithium battery materials and taking corresponding preventive measures are of great significance. In this review, the heat source and thermal hazards of lithium batteries are discussed with an emphasis on the designs, modifications, and improvements to suppress thermal runaway based on the inherent structure of lithium batteries. According to the source of battery heat, we divide it into reversible heat and irreversible heat. Additionally, superfluous heat generation has profound effects, including thermal runaway, capacity loss, and electrical imbalance. Thereafter, we emphatically discuss the design and modification strategies for various battery components (anodes, cathodes, electrolytes, and separators) to suppress thermal runaway. Preparation of solid electrolyte interphase layers with excellent thermal stability and mechanical properties is the core of the modification strategy for anode materials. Additives, stable coatings, elemental substitution, and thermally responsive coating materials are commonly used to improve the safety of cathodes. Novel electrolyte additives, solid-state electrolytes, and thermally stable separators provide a good opportunity to solve the thermal runaway problem of next-generation high-performance electrochemical storage devices.

Low-activation vanadium alloys, with the reference composition of V–4Cr–4Ti have been considered as one of the most promising candidate materials for structural components such as the blanket in future fusion reactors, thanks to their excellent neutron irradiation resistance, superior high-temperature mechanical properties, and high compatibility with liquid lithium blankets. The self-cooled liquid lithium blanket using structural materials of vanadium alloys is an attractive concept because of the high heat transfer and high tritium breeding capability. After more than 2 decades of research, technological progress has been made in reducing the number of critical issues for application of vanadium alloys to fusion reactors. In this paper, the recent research and development activities of vanadium alloys are summarized, including significant progress achieved on fabrication technology and composition optimization, coating and corrosion, improved understanding of irradiation effects upon microstructure and material properties, retention of hydrogen isotopes, as well as advancements in joining and welding. In particular, the fact that recent products from China, Japan, US and France showed similar properties which meant the fabrication technology has been almost standardized.

This novel investigation suggests the implementation of famous numerical technique namely Galerkin finite element technique for peristaltic study of non-Newtonian fluid confined by a porous tube. The rheological consequences for non-Newtonian materials are executed by using micropolar fluid. The problem is modeled in form of Navier–Stokes expressions. The flow simulations are carried by utilizing the impact of the magnetic field and uniform porous medium. Additionally, the role of inertial forces is also observed as a novelty for current analysis. Unlike typical investigations, the presumptions of lubrication theory are not implemented in the modeling which allows the participation of inertial forces in the governing equations and provided the results independent of wavelength. The solution of the modeled set of coupled non-linear partial differential equations is obtained by Galerkin finite element method with quadratic triangular elements. The verification of attained numerical results with available literature for low Reynolds number approximation is also presented and found in excellent agreement. It is observed that the peristaltic mixing enhances with increasing the inertial and Lorentz force while reverse observations are noticed with for the dense porous medium. An increase in pressure rise per wavelength is observed for micropolar fluid as compared to that of viscous fluid. It is further claimed that the peristaltic mixing is improved with increasing the Reynolds number and permeability of porous medium.

The spin-forbidden nature of triplet exciton transitions is a limitation for achieving a carbon dots-based material with room-temperature phosphorescence (RTP). Here, fluorine-nitrogen co-doped carbon dots (FNCDs), prepared using the solvothermal method and further gas-phase fluorination from fructose and diethylenetriamine (DETA), were found to exhibit RTP lifetime and quantum yield of 1.14 s and 8.3%. By comparing the structure and performance of the nitrogen-doped carbon dots (NCDs) and FNCDs, it was found that the RTP of FNCDs originates from the π→π∗ and n→π∗ electron transitions C–N/C N, which can be attributed to the small energy gap between the singlet and triplet states. We further explored the mechanism of RTP by analyzing the hydrogen bonding between carbon dots and polyvinyl alcohol matrix. The semi-ionic C–F bonds also enhance intramolecular and intermolecular hydrogen bonding and reduce the quenching of RTP without the oxygen barrier. Furthermore, we applied the prepared aqueous FNCDs as an advanced security ink for information printing and anti-counterfeiting.

Lithium orthosilicate (Li4SiO4) is regarded as a candidate solid tritium breeding material for the fusion reactors, but the phase control and densification for this ceramic are difficult. Microwave-induced solution combustion synthesis (MSCS) offers an efficient and flexible route for preparing the tritium breeders in a single step. The combustion process can be effectively controlled by the microwave power output and the fuel-to-oxidizer ratio (ϕ), which can be taken advantage of for the phase control of the product. The results show that the combustion temperature increases linearly with the increase of the ϕ value, and the Li4SiO4 becomes the main product when the ϕ value is higher than 0.75. Lithium metasilicate (Li2SiO3) is detected in minimum quantities in the products, and its content can be reduced when the microwave power output is 1100 W, which can be further removed by calcination at 873 K for 2 h. The thermal analysis results show that the redox reaction between the LiNO3 and citric acid provides the heat for the combustion. The ceramic body can be sintered to 84% of the theoretical density at a low temperature of 1073 K, and the relative density is close to 96% with high purity at the sintering temperature of 1373 K.

Metalation reaction of metal-free phthalocyanine molecule with Co atom adsorbed on Au(111) surface has been studied in situ at single atom/molecule scale by low-temperature scanning tunneling microscopy (STM) experiment combined with simulations based on density function theory calculations. Through manipulations using STM tip, we showed a controlled manner to have a single metal-free phthalocyanine molecule react with a Co atom to form Co phthalocyanine molecule. In this reaction process, an intermediate state originating from π-d interaction between the metal-free phthalocyanine molecule and Co atom has been identified. Moreover, we also revealed that the redox reaction represented as bond breaking and bond forming relative to the Co and pyrrolic N atoms, not pyrrolic H atoms, is a key process for dehydrogenation and metalation reaction. Our DFT calculations provided theoretical supporting for the above conclusions, and further understanding of the related mechanisms.

Aconitine and hypaconitine are the main active ingredients of Radix Aconiti, paeoniflorin and albiflorin are the primary components of Radix Paeoniae Alba. Both Radix Aconiti and Radix Paeoniae Alba are herbs that are commonly used in traditional Chinese medicine. This study sought to explore the mechanistic transport of aconitine and hypaconitine across MDCK-MDR1 cells and to assess the effect of paeoniflorin and albiflorin on aconitine and hypaconitine transmembrane transport as a potential attenuation mechanism. Drug cytotoxicity was tested via the MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, and transport studies were performed in both directions. The effects of drugs on P-gp ATPase activity, P-gp efflux function, MDR1 mRNA and P-gp expression were evaluated in MDCK-MDR1 cells. Aconitine and hypaconitine treatment with the verapamil could significantly decrease the efflux rate (ER). The ER of aconitine and hypaconitine were significantly increased with the coadministration of paeoniflorin and albiflorin, suggesting that paeoniflorin and albiflorin can promote the efflux of these two alkaloids. Aconitine and hypaconitine can induce P-gp enzymatic activity, inhibit P-gp-mediated efflux, and downregulate the expression of P-gp protein to produce cytotoxic effects. When treatment in combination with paeoniflorin and albiflorin, it could stimulated P-gp ATPase activity, increasing mRNA expression, enhance P-gp efflux function, and upregulate P-gp protein expression.

Pure TiO2 and different concentrations of Cu–doped TiO2 with anatase/rutile/brookite triphasic structure were successfully synthesized through a simple hydrothermal process and characterized by X–ray diffraction (XRD), Raman, scanning electron microscope (SEM), transmission electron microscope (TEM), X–ray photoelectron spectra (XPS), diffuse reflectance spectra (DRS), photoluminescence spectra (PL) and Brunauer-Emmett-Teller surface area (BET). Both pure and Cu–doped TiO2 show relatively high photocatalytic activity owing to their considerable surface areas. Moreover, the three–phase coexisting structure and the conversion between Cu2+ and Cu+ ions facilitate the separation of photogenerated electrons and holes, which is favorable for photocatalytic performance. 1%Cu–TiO2 exhibits the highest photocatalytic activity and the degradation degree of rhodamine B (RhB) reaches 93.5% after 30 min, which is higher than that of monophasic/biphasic 1%Cu–TiO2. ·O2− radical is the main active specie, and h+ and ·OH are subsidiary in the degradation process.

Smart thermal interface materials must exhibit self-healability and high thermal conductivity (k) and elastic deformation as they can experience repeated compression and undergo sudden damage. However, it remains challenging to ensure high phonon mobility/efficient phonon transfer, self-healing, and good elasticity by optimizing its molecular orientation or cross-links. Herein, a self-healing and elastic polyimide copolymer (EMPI) cross-linked by flexible and rigid segments is uniformly filled into the gaps of a forest of vertically aligned carbon nanotubes (VACNTs). The EMPI@VACNTs composite exhibits a high k value at 10.83 ± 0.22 W m−1 K−1, low interfacial thermal resistance at 6.83 ± 0.15 K mm2 W−1, high elastic compressive deformation (30% at 2.5 MPa), and strong surface adhesion (0.3 MPa). Further, it could recover 90.8% of its elastic modulus and 92% of its thermal resistance after self-healing at 80 °C for 80 h. An EMPI@VACNTs-Cu device exhibits efficient heat conduction not only by recovering after gradient compressive strains of up to 30% but also by self-healing its damage or reforming the interface with Cu. Thus, the thermally conductive, self-healing, and elastic EMPI@VACNTs composite opens new avenues for smart thermal management in various high-power/intelligent devices.

Background Parabolic trough solar collectors (PTSCs) are used to focus the solar rays on absorber tube. The main aim of this paper is to investigate the effects of applying novel corrugated absorber tube filled with hybrid nanofluid on energy efficiency of a novel double fluid PTSC to achieve the maximum energy efficiency value. Method The Eulerian-Eulerian two-phase model is employed for modelling the PTSC and evaluating its energy efficiency. Numerical study is carried out for different values of Reynolds number (Re), nanoparticles volume fraction (ϕ) and geometrical parameters of novel corrugated absorber tube. Findings It is found that usage of corrugated absorber tube has a significant effect on energy efficiency of single- or double fluid parabolic trough solar collectors. Besides it is understood that usage of double fluid system for collector with smooth channel can also increase the energy efficiency, but not more than using corrugated channel for single fluid collector. Moreover, usage of double fluid system at higher Re is also efficient. The results also show that the efficiency of the PTSC enhances with increasing the nanoparticles concentration. Finally, the optimum model of corrugated absorber tube is presented.

Helical carbon nanotubes (HCNTs) are a kind of potential microwave absorption (MA) material due to their chiral and dielectric properties. However, the inert surface property makes HCNTs with poor polarization loss ability and impedance matching characteristic, which impedes its ability in attenuating microwaves. Herein, the HCNTs were modified with defects and functional groups on the surface to optimize their electromagnetic response characteristics and achieve an enhanced MA performance. The experimental results show that the modified HCNTs (F-HCNTs) exhibit a significant enhancement in MA performance when compared with HCNTs. The minimum reflection (RLmin) loss of F-HCNTs reaches −45.4 dB at 17.5 GHz at a thickness of 2.4 mm and the bandwidth of RL < −10 dB is 3.6 GHz (from 14.4 to 18.0 GHz). Further analysis demonstrates that proper modification of HCNTs leads to enhanced dielectric loss ability and optimized impedance matching characteristics, both of which are beneficial to the MA performance of HCNTs.

Belite - ye’elimite - ternesite (BYT) cement clinker has attracted much attention due to its advantages of wide range of raw materials, low energy consumption and low carbon emission compared with ordinary portland cement (OPC). In this experiment, chemical reagents were used as raw materials. The effects of calcination temperature and calcination time on clinker synthesis were studied. The best sintering temperature was determined by sintering in rang of 1150-1300°C (setting a temperature point every 30 °C), and then the samples were sintering for 1-6 hours (setting every hour) to determine the best sintering time. The stable condition of the BYT clinker was determined. The phase composition and microstructure of cement clinker were analyzed by X-ray powder diffraction (XRD) Rietveld refinement and Scanning Electronic Microscopy (SEM). The results showed that the desired clinker could be obtained by sintering at 1210°C for 2 hours. In the presence of C4A3$, the hydration of C5S2$ was accompanied by the formation of gypsum and the precipitation of ettringite.

In this study, a new Fe-6Mn-4Al-0.4C high strength medium manganese hot rolled steel sheet was designed. The influence mechanism of the intercritical annealing (IA) temperature on microstructure evolution and mechanical properties of experimental steel were studied by SEM and XRD. The experimental steel was held for 30 minutes at 640°C, 680°C, 720°C, 760°C, 800°C, respectively. When the annealing temperature was 640°C, cementite particles precipitated between the austenite and ferrite phase boundary. As the annealing temperature increased, the cementite gradually dissolved and disappeared, the fraction of lamellar austenite increased significantly. When the annealing temperature is 800°C, the coarse equiaxed austenite and ferrite appeared. The yield strength (YS) decreased, the product of strength and elongation (PSE) and total elongation (TE) both increased first and then decreased, while the ultimate tensile strength (UTS) showed the opposite trend. The experimental steel exhibited excellent comprehensive mechanical properties after held at 760°C for 30 min. The UTS was 870 MPa, the YS was 703 MPa, and the TE was 77 %, the PSE was 67 GPa·%.

Through the Gleeble3500 thermal simulation test machine, the phase transformation law of Nb microalloyed steel was studied and tested. After the compression deformation, it was cooled to room temperature at different speeds. Obtain the dynamic continuous cooling transformation diagram and the scanning structure diagram of the test steel, and then analyze the phase composition under different cooling speeds through JMatPro material performance simulation. The results show that: at a lower cooling speed (0.1°C/s), austenite decomposition is a diffusion-type phase change that takes place in a high-temperature region, and carbon atoms can diffuse sufficiently. At a moderate cooling rate (1°C/s), the bainite phase transition is a semi-diffusion phase transition in which carbon atoms are displaced in a non-cooperative thermally activated transition mode. When the cooling rate is high (15°C/s), the martensitic transformation is a non-diffusion-type transformation carried out in the low temperature region, and the atoms are directly transferred from the austenite lattice to the martensite lattice. With the increase of the cooling rate and the decrease of the transition temperature, from low-speed cooling→medium-speed cooling→high-speed cooling, respectively, the diffusion type phase transition→semi-diffusion type phase transition→the non-diffusion type phase transition. At different cooling rates, the continuous cooling transition diagram simulated by JMatPro is basically the same as the phase transition in the dynamic continuous cooling transition diagram of the test steel, which proves that the simulation prediction of the dynamic continuous cooling transition of the test steel by the JMatPro software has high accuracy and applicability.

A principle investigation of the fingerprint resistance, alcohol resistance, solvent resistance, humidity resistance, high temperature resistant yellow degeneration and black tarnish resistance of pure Zinc and Zn-Al-Mg coating were performed in this study. To detect above surface performance and make some constructive suggestions, a series of simulations experiments and a surface performance evaluation system based on light color differentiation measurement instrument were designed. The results show that the two products both can meet the needs of users in above-mentioned surface performance, besides pure Zinc coated product has more advantages in this performance in comparison to Zn-Al-Mg coated product. Users should pay attention to clean the fingerprint regularly which attached to the surface of the steel plate during use and the protection with the exposed surfaces of the steel during shipping.

The low-cost and high-capacity micron silicon is identified as the suitable anode material for high-performance lithium-ion batteries (LIBs). However, the particle fracture and severe capacity fading during electrochemical cycling greatly impede the practical application of LIBs. Herein, we first proposed an in situ reduction and template assembly strategy to attain a weave cage-like carbon nanostructure, composed of short carbon nanotubes and small graphene flakes, as a flexible nanotemplate that closely wrapped micron-sized mesoporous silicon (PSi) to form a robust composite construction. The in situ formed weave cage-like carbon nanostructure can remarkably improve the electrochemical property and structural stability of micron-sized PSi during deep galvanostatic cycling and high electric current density owing to multiple attractive advantages. As a result, the rechargeable LIB applying this anode material exhibits improved initial Coulombic efficiency (ICE), excellent rate performance, and cyclic stability in the existing micron-sized PSi/nanocarbon system. Moreover, this anode reached an approximation of 100% ICE after only three cycles and maintains this level in subsequent cycles. This design of flexible nanotemplated platform wrapped micron-sized PSi anode provides a steerable nanoengineering strategy toward conquering the challenge of long-term reliable LIB application.

The performance of piezoelectric ultrasonic transducer (PUT) is obviously affected by its matching layer. An intelligent optimization method for matching layer of PUT is proposed to fabricate PUT with high performance. The original data, including matching layer and performance parameters of PUT, is obtained by PiezoCAD software. Then the neural network models are established to mathematically characterize the effect of matching layer on the performance of PUT. The optimization criteria for PUT is constructed according to its performance requirements, such as center frequency (CF), bandwidth (BW) and pulse width (PW). In order to decrease the material cost, the thicknesses of matching layers are also considered in the optimization criteria. The modified particle swarm optimization algorithm is used to optimize the thicknesses of matching layers (Ag-epoxy and Parylene C). According to the designed performance, the optimized thicknesses of Ag-epoxy and Parylene C are about $54~\mu \text{m}$ and $21~\mu \text{m}$ , respectively. Based on the optimized thicknesses of matching layers, the simulated and experimental performances of PUT well agree with the designed ones. In addition, compared to the traditional quarter-wavelength theory, the proposed method can effectively decrease the materials cost. The −6dB BW and PW of PUT fabricated according to the optimized parameters are about 68.5% and $0.123~\mu \text{s}$ , which are better than that fabricated according to the quarter-wavelength theory (about 50% and $0.147~\mu \text{s}$ ).

Exploring lightweight electromagnetic wave absorption materials is urgently needed to satisfy the miniaturization and integration of artificial intelligence and 5G technologies. Herein, nitrogen-doped graphene (N-GN) is successfully fabricated through a simple hydrothermal method, which can float in the water. Except for keeping the sheet-like structure of GO, nitrogen-doped graphene shows a reticular-like structure with more wrinkles and crinkles, which is crossed and interconnected to each other. The introduced nitrogen heteroatoms may induce dipole polarization, and the special interconnected reticular-like structure may improve the energy dissipation capacity. These features make nitrogen-doped graphene process improved dielectric loss and enhanced electromagnetic wave absorption performance. When the mass fraction of N-GN is only 10 wt%, N-GN shows a maximum reflection loss value of − 21.7 dB at 14.3 GHz with an absorber thickness of only 1.78 mm. This work indicates that nitrogen-doped graphene is a good candidate of lightweight dielectric materials.

The paper focused on the moisture absorption and hygrothermal degradation of composite laminates repaired via double scarf method. Experimental works were carried out on double scarf-repaired compo...

In addition to the demand of thin, lightweight, broadband and high-efficient characteristics, exploring microwave absorbents with superior resistance to oxidation and corrosion is urgently need for practical applications. Herein, carbon nanofibers embedded by α-Fe2O3, Fe or Fe3C nanocrystals are prepared through electrospinning technique followed by carbonization in different atmospheres. The one-dimensional structures can intertwine into three-dimensional conductive network, which is favored for energy dissipation. The Fe3C/N-doped carbon nanofibers show boosting microwave absorption properties compared to the bare carbon, α-Fe2O3/C and Fe/C nanofibers. The Fe3C/N-doped carbon nanofibers show an optimal reflection loss of −57.9 dB at 5.8 GHz with a thickness of 4.1 mm. Meanwhile, a reflection loss of −54.5 dB can be achieved at 17.8 GHz, when the absorber thickness is only 1.5 mm. The superior microwave absorption properties are attributed to the dipole polarization, interfacial polarization and ferromagnetic resonance, induced by the synergistic effect of Fe3C nanocrystals and carbon nanofibers. Moreover, acid-soaking and air-annealing treatments reveal that the Fe3C/N-doped carbon nanofibers show remarkable corrosion and oxidation resistance. This work suggests that encapsulating magnetic nanocrystals in dielectric carbon-based materials is an efficient strategy to construct high-efficient lightweight microwave absorbents with oxidation/corrosion resistance.

Density functional theory calculations were used to study the effects of inherent impurities C, N, and O on the stability and the self-trapping of interstitial He atoms in body-centered-cubic vanad...

Lithium (Li) metal anodes are regarded as prospective anode materials in next-generation secondary lithium batteries due to their ultrahigh theoretical capacities and ultralow potentials. However, inhomogeneous lithium deposition and uncontrollable growth of lithium dendrites always give rise to the low lithium utilization, rapid capacity fading, and poor cycling performance. Herein, we design the lithiophilic covalent organic frameworks (COFs) containing preorganized triazine rings and carbonyl groups as the multifunctional interlayer in lithium metal batteries (LMBs). Triazine rings rich in lone pair electrons can act as the donor attracting Li ions, and carbonyl groups serve as Li-anchoring sites effectively coordinating Li ions. These periodic arranged subunits significantly guide uniform Li ion flux distribution, guarantee smooth Li deposition and less lithium dendrite formation. Consequently, the symmetric batteries with COF interlayers exhibit an extraordinary cycling stability for more than 2450 and 1000 h with ultralow polarization voltage of about 12 and 14 mV at 0.5 and 1.0 mA cm-1. Coupling with sulfur (S) cathodes and LiFePO4 (LFP) cathodes, the full cells also demonstrate superb energy density achievement and rate performance. With introducing lithiophilic COFs interlayers, the Li-LFP batteries exhibit high capacity of 150 mAh g-1 and 86% capacity retention after 450 cycles at 0.5 C.

Afterglow materials with long-lived emission after ceasing the excitation source have exhibited tremendous potential for various applications. However, the inherently dim afterglow emission makes i...

In order to effectively and flexibly control acoustic pattern, an efficient optimization design method of acoustic liquid lens (ALL) is developed by the frame of particle swarm optimization (PSO) algorithm. The ALL is composed of ethanol and dimethicone, and its parameters include ethanol concentration (EC), volume fraction of dimethicone (VFD), and total volume (TV). Based on the established finite element model and orthogonal design method, the data of acoustic pattern and ALL can be obtained by using COMSOL Multiphysics. Based on the simulation data, the neural network models are constructed to characterize the relationship between the parameters of ALL and the performance of acoustic pattern. The optimization design criteria of ALL are constructed based on the performance parameters of acoustic pattern, including focal distance (FD), transverse resolution (TR), and longitudinal resolution (LR). Based on the optimization criteria, the modified PSO algorithm is utilized to optimize the design parameters of ALL in the developed method. According to the desired FD, TR, and LR of acoustic pattern (20, 1, and 17 mm), the optimized EC, VFD, and TV of ALL are about 0.838, 0.165, and 164.4 $\mu \text{L}$ . The performance parameters of acoustic pattern verified by simulation and experiments agree with the desired ones. In addition, using 6 MHz ultrasonic transducer with the optimized ALL, the ultrasonic imaging of tungsten wires and porcine eyeball further demonstrates the effectiveness and feasibility of the developed method.

Low mechanical strength, especially at high temperatures, is the key problem that limit the application of FeCrAl alloys as the accident tolerance fuel (ATF) cladding materials. Dispersion strengthening by carbide nanoparticles is an effective way to improve mechanical properties at high temperatures. In this work, an ultrafine grained FeCrAl-0.6 wt.% ZrC alloys with excellent mechanical properties were fabricated successfully by mechanical milling and spark plasma sintering. The effect of milling speed on powder characteristics, microstructure and mechanical properties of FeCrAl alloys were investigated. The particle size of the powders increase significantly after milling at 400 rpm, while it has a lower oxygen content. Increasing the milling speed decreased the resultant grain size and improved relative density. Transmission electron microscope (TEM) demonstrated the nano ZrC particles uniformly distributed in the matrix at higher milling speed, which effectively promotes grain refinement and dispersion strengthening. The results of mechanical properties show that the tensile strength, percentage elongation and hardness of FeCrAl-0.6 wt.% ZrC alloys at room temperature (RT) reached up to 1.05 GPa, 349.86 HV and 12.1%, respectively, after milling at 400 rpm. It is worth noting that the FeCrAl-0.6 wt.% ZrC alloy also exhibited a good high-temperature strength more than 110 MPa at 800 ℃, which is about 55.4% and 24.7% higher than previously reported FeCrAl-0.5 wt.% ZrC and FeCrAl-1.0 wt.% ZrC alloys, but the plasticity is reduced. The results demonstrated that the excellent mechanical properties were not only attributed to the dispersion strengthen by nanosized ZrC, a good interface bonding between Fe matrix and nanosized ZrC, but also the ultra-fine grained structure induced by the milling process.

In this study, N/O co-doped cage-type biomass carbon (NOBC) was prepared through a simple and facile hydrothermal reaction and two-step carbonization method. As the anode of a potassium ion battery, NOBC displays a superhigh long-cycling performance and a super high rate performance. NOBC-2 provides an excellent reversible capacity of 251.2 mAh g−1 after 1500 cycles at 0.5 A g−1, and an excellent performance of 334.6 mAh g−1 at a high current density of 5 A g−1 (after 2000 cycles). The reversible capacity of 124.19 mAh g−1 can be maintained even after 5000 cycles at 10 A g−1. The excellent performance of NOBC is attributed to the unique hollow cage structure, internal 3D carbon network structure and N/O co-doping. Based on the results of detailed fundamental analysis, the pseudo-capacitance mechanism contributes to the higher K ion storage process in NOBC-2. Density functional theory (DFT) calculations further show that N/O double doping can promote the adsorption of K ions in biomass carbon materials and improve the conductivity of the materials. The simple synthesis route and excellent electrochemical performance provide new insights for the search for novel carbon-based K storage anode materials with high energy and long cycle life.

The introduction of solvent additives has become a general approach in optimizing the active layer morphology in organic photovoltaics (OPV) to achieve high power conversion efficiency. It is of general interest to understand the mechanism of how additives optimize the thin-film nanostructure formation such as crystallization kinetics and phase separation. In the current manuscript, state-of-the-art nonfullerene bulk heterojunction blends, PM6:IT-4F mixture, are used in a slot-die coating experiment. The 1,8-octanedithiol (DIO)-aided fabrication leads to a significant increase in the power conversion efficiency (PCE) from 10.11 to 12.67%. Exciton dissociation and carrier transport have also been improved, largely associated with morphology improvement. Time-resolved crystallization kinetics during PM6:IT-4F film formation under different processing conditions was studied by in situ grazing-incidence wide-angle X-ray scattering (GIWAXS), in which a detailed polymer fibril morphology formation was seen. The Johnson–Mehl–Avrami–Kolmogorov (JMAK) crystallization analysis affords insights that the addition of the DIO additive in a small amount would not only increase the nucleation rate during the nucleation and growth stage but also introduce secondary fibril crystal perfection via burst nucleation-mediated crystallization to a grain boundary-induced crystallization stage change. These observations can be of general interest to the OPV community in manipulating the printed solar cell morphology and efficiency toward the commercial application.

ZrB2 particles were preset to the C-AlSi interface to improve oxidation resistance of C/C preform and adjust the microstructure of the interpenetrated C/C-AlSi composite prepared through pressure infiltration of eutectic AlSi into a fiber fabric based porous C/C skeleton. Micro-morphology investigations suggested that the AlSi textures were changed from dendritic to petals-like state, and the nano to micro-scale ZrB2 particles were dispersed into AlSi and affected the distribution of Al and Si nearby carbon. Tests demonstrated that C/C-AlSi have slight lower density and thermal expansion coefficient, and higher original compressive strength, while C/C-ZrB2-AlSi composites presented an outstanding strength retention rate after thermal shock. Fracture and micro-morphology indicated that the influence of the preset ZrB2 to the interface of carbon and alloy greatly affected the generation and propagation of cracks, which determined the diverse compression behaviors of the composites before and after thermal shock.

Nanostructured α-Fe2O3 (hematite) were successfully synthesized via a simple plant extract-assisted method using the leaf extract of Azadirachta indica (neem) as the reducing and stabilizing agent and ferric chloride as the precursor. In the absence of additional toxic reducing and stabilizing agents, the plant phytoconstituents also assist in the final shape of the nanocatalyst giving it more reactive sites. The as-synthesized nanostructured hematite was well characterized. FT-IR analysis verified 523 and 458 cm−1 as absorption edge of the α-Fe2O3 NPs. XRD patterns revealed the sample to be of rhombohedral (hexagonal) structure with crystallite sizes of 18.9 nm. SEM and TEM images showed the α-Fe2O3-AI with bio-C doping to be of perfect crystallinity compared to the normal chemically synthesized α-Fe2O3, which shows some aggregation. Spectrum from the XPS confirmed the α-Fe2O3-AI with bio-C doping to be mainly composed of Fe, O, and C. The nanostructured α-Fe2O3-AI with small bio-C doping possess large surface area and exhibited high performance as a heterogeneous catalyst for the degradation of tetracycline (TC, 50 mg/L) by the synergistic effect of the UV-Fenton (UV/α-Fe2O3/H2O2) compared to the Fenton-like oxidation (α-Fe2O3/H2O2) and photocatalysis (UV/α-Fe2O3). Furthermore, the catalyst demonstrated a broad scope pH for efficient UV-Fenton degradation for TC and can be reuse up to five consecutive cycles without significant loss in activity.

To suppress space charge accumulation and minimize the antioxidant migration, polyethylene (PE) grafted with reactive hindered amine antioxidant MC prepared by melt radical grafting is investigated in this work. Fourier transform infrared spectroscopy is used to investigate the grafting reaction, which shows that the antioxidant MC is successfully introduced onto PEe Space charge distribution, DC conductivity, DC breakdown strength and thermally stimulated current are measured and the electronic structure is calculated from first-principles. The results show that PE grafted with antioxidant MC can effectively suppress space charge accumulation, reduce DC electrical conductivity and enhance DC breakdown strength. The polar functional groups of antioxidant MC anchored on PE macromolecular chain form immobile deep traps at the grafted MC sites, which can capture space charges and scatter charge carriers to reduce the amount, mobility and energy of charge carriers. Seen from the oxidative induction time of the specimens before and after acetone extraction, the level of retention of the grafted antioxidant MC are significantly higher than those of conventional antioxidant 300 and antioxidant 4020, which indicates that PE grafted with antioxidant MC has excellent long-term thermal oxidation stability.