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In this paper, multiwall carbon nanotube-ZnO (MWCNT/ZnO) was melt-blended with polyethylene (PE) by a Haake-Buchler Rheomixer. The mechanical properties, thermal stability and dispersion degree of the composite materials was characterized. Differential scanning calorimetry, X-ray diffraction analysis, thermogravimetry, tensile test and SEM were carried out. The results showed that with the addition of MWCNT/ZnO, the crystallinity and thermal degradation temperature of PE changed. 0.2phr MWCNT/ZnO/PE exhibited crystallinity that was 10% higher than PE. With the addition of MWCNT/ZnO, the tensile strength of PE decreased gradually, but the elongation at break increased first and then decreased. When MWCNT/ZnO content is 0.2phr, the elongation at break of the composite is close to 532.21%, which is 116% higher than that of pure PE.

A series of Fe3O4/PLA composites are controllably prepared using consecutive reaction route. The neat PLA and its composites are characterized by FT-IR, WAXRD and XPS for composition analysis. The performances of PLA and Fe3O4/PLA composites are, respectively, determined by SEM, VSM, CAM, POM, DSC and TG. Fe3O4 particles are a good dispersion in the PLA matrix, and the saturation magnetization values of PLA have increased from 0.33 to 5.06 emu/g. When PLA is transformed into composites, the mean thickness of composites has decreased and water contact angle of composites has increased due to heavy and hydrophobicity Fe3O4. After addition of Fe3O4 particles, the 50 k, 100 k and 200 k PLA’s crystallization rate is severally increased to 1.84, 1.56 and 1.44 times. It is concluded that the Fe3O4 particles are the efficient crystallization nucleating agent of PLA and faster accelerate the crystallization of low molecular weight PLA in comparison with high molecular weight PLA. The melting points of Fe3O4/PLA composites slightly have decreased compared with the neat PLA, which is in accord with the melting point of the mixture that is lower than that of the pure substance. By introducing 5 mass% of Fe3O4 particles to PLA, the initial decomposition temperatures reached to higher temperatures as compared to the neat PLA, and the final char yield is about 4.60%. The well dispersion of the particles in the PLA matrix is thought to be an effective barrier to the permeation of heat, which would improve the thermal stability.

Municipal solid waste incineration fly ash (MSWIFA) is a kind of hazardous waste. In the recent years, the demand for the disposal of MSWIFA has gradually increased with the increase of its production. The co-processing of MSWIFA in cement kiln has become the future development trend in this field due to the advantages of large disposal capacity, thorough disposal and low secondary pollution. In this paper, the life cycle assessment (LCA) was used to analyze the environmental impact of cement kiln co-processing MSWIFA, and the influence of allocation method of by-products in pretreatment process on calculation results was discussed. The results of analysis on the pretreatment of MSWIFA using the water-washing process showed that the allocation method of by-products will affect the calculation results to a certain extent, especially in the toxicity-related indicators, and for pretreatment process, electricity production process is the key link to causing environmental impact. The environmental analysis for clinker product shows that the contribution ratio of pretreatment process calculated by extended boundary method was 3.33% larger than that of mass allocation method in acidification potential(AP), and 3.32% smaller than that in WCP.

Reducing NO using coal and active carbon with and without the addition of catalysts were investigated in a fixed bed reactor at a wide temperature of 250-850 °C. The results indicated that without the catalysts, NO reduction using coal was significantly better than that using active carbon. When coal was used as reducing agent, the addition of catalysts made the NO reduction occurred earlier and the effect of catalysts was temperature-dependent. When active carbon was used to reduce NO, the addition of catalysts was not ideal and only CuO showed a significant positive effect above 700 °C.

Blast furnace slag has good adsorption performance and can be used to adsorb heavy metal ions in waste liquid. It’s worth studying whether the blast furnace slag absorbing heavy metal ions will pose a potential threat to the environment during the process when used in cement-based materials.This paper has studied the leaching amount of copper ions in the blast furnace slag-cement system was analyzed, and analyzed the leaching kinetics of copper ions. The results showed that the leaching amount of copper ions in the blast furnace slag-cement system that adsorbed copper ions basically met the national standard, and the solidified body age was 28 days,blast furnace slag content 30% is the smallest condition for the amount of copper ion leaching.The leaching model of copper ions in the blast furnace slag-cement system is the Elovich equation, which is a heterogeneous diffusion process. The longer the curing age is the slower the leaching process is completed and do not cause environmental pollution during long-term use.

Slag is widely used as mineral admixtures in cement-based materials by its potential hydration activity. It has the advantage of saving resources and energy, reducing carbon emission, improving the performance of concrete, and plays an increasingly important role in the building materials industry. But the early strength of slag is low, and the industrialization of useful hydration products also need to be activated, so the utilization rate of slag in high grade cement is restricted. The hydration activity of slag depends not only on the content of vitreous in slag, but also on the structure of vitreous slag. To explore slag glass micro composition and structure of its active role, The slag micro-structure was analyzed from the structure levels, and then the factors affecting the activity of slag was evaluated. The potential advantages and disadvantages of some different methods to active slag were discussed such as physical ways, chemical activation method and compound activation way. The existing problems and development direction of improving the activity of slag were summarized , which could provide a valuable reference for the efficient use of slag.

Metal-organic chemical vapor deposition (MOCVD) is a key technique for developing and manufacturing zinc oxide (ZnO) devices. The film quality and performance of these devices are influenced by the process parameters. In this study, the film deposition rate and film uniformity obtained from the simulations and experiments under different process parameters, such as the substrate temperature, operating pressure, mass fraction of the source gas, and inlet flow rate, are compared and verified. In addition, the corresponding temperature field, flow field, distribution of source mass fraction, and velocity field are analyzed using the computational fluid dynamics (CFD) method to explain the influence of the flow field change on deposition rate and film uniformity. This study also presents the correlation test for the film uniformity between the simulation and experimental results; it was found that all the 16 sets of results are significantly correlated and that more than half of them are highly correlated. To ensure the consistency of the experimental results and to prove their reliability, the repeatability test and stability test are conducted.

Hot compressive experiments of the laser solid formed (LSFed) TC4 titanium alloy were conducted at a wide temperature range of 650–950 °C and strain rate of 0.01–10 s−1. The Arrhenius-type constitutive models of the LSFed TC4 alloy were established at the temperature range of 800–950 °C and of 650–800 °C, respectively. The average relative error between the predicted stresses and experimental values in those two temperature ranges are 10.4% and 8.3%, respectively, indicating that the prediction models constructed in this paper are in a good agreement with experimental data. Processing maps were established by the principle of dynamic materials modeling on the basis of the data achieved from the hot compression experiments. The processing parameters corresponding to the stable and unstable regions of material deformation can be determined from the processing maps. The microstructure evolution of the stable and unstable regions of the samples after tests were observed. Finally, the effect of hot compressive parameters on the microstructure were investigated to research the dynamic recrystallization and the texture of the deformed LSFed TC4 alloy.

Summary Smart electromagnetic interference (EMI) shielding materials with tunable EM wave response characteristics are attractive for future EM devices. Here, we report an off/on switchable EMI shielding material that can be tuned from EM wave transmission to shielding and vice versa by mechanical compression and decompression. This smart material is prepared by filling conductive carbon nanoparticles into wood-derived lamellar carbon aerogel, showing reversible compressibility and strain-sensitive conductivity. The original aerogel has good impedance matching and low dielectric loss, allowing the EM wave to pass through. Mechanical compression enables the carbon nanoparticles to establish highly conductive pathways in the aerogel, which significantly increases the conductivity of aerogel and thus activates its EMI shielding performance. This function switch is reversible by repeatedly compressing and decompressing the aerogel. The availability of such a never-before-realized off/on switchable EMI shielding material provides an opportunity for the development of advanced smart EM devices.

Carbon-based materials are highly desirable for developing flexible supercapacitor electrodes. However, due to the limitations of the carbon electrode structure including the low accessible active ...

The metal magnetic memory is used to detect the micro damage of structure based on the SMFL (self-magnetic flux leakage) effect, but it lacks an effective comprehensive diagnosis index suitable for...

A spherical propagating flame experiment was performed to study the laminar burning velocities (LBVs), Markstein lengths, and onset of instability of flame fronts for dimethyl carbonate (DMC) at 37...

In this paper, effects of sintering temperature (Ts) and dwell time (td) on crystalline structure, microstructure and electrical properties (dielectric and ferroelectric) of BiFe0.96 Zn0.02Ti0.02O3...

Temperature monitoring is an essential task in cryogenic engineering to ensure the safety of equipment, where highly sensitive and reliable sensors are required to provide real-time and accurate information about temperature. Titanium (Ti)–copper (Cu)-coated fiber Bragg grating (FBG) temperature sensors with a gradient of material properties to minimize thermal stresses are hence fabricated by a combination of Ti/Cu magnetron sputtering and Cu electroplating. The thermal characteristics and thermal fatigue behavior of the sensors are investigated. The sensors exhibit significantly higher sensitivity than that of the bare FBGs at cryogenic temperatures down to 79 K, with good repeatability and stability. Their response to the temperature changes can be precisely described by a quadratic-polynomial equation. No obvious variations in the zero-point, the reflection spectrum, and the temperature sensitivity of the sensors exposed to thermal fatigue from 77 K to room temperature are observed before fatigue failure which could be attributed to the formation and growth of subcritical cracks within the fiber rather than that of fatigue cracks within the metallic coatings, as a result of the cyclic thermal stresses induced by the large differences in coefficient of thermal expansion between the silica optical fiber and the metallic coating materials. The results demonstrate that the multilayer metal-coated FBG sensors provide great potential for temperature measurements or temperature compensation in cryogenic engineering by proper selection of metallic coatings with a gradient of material properties.

This article proposes a novel stator flux-concentrated hybrid permanent magnet memory machine (SFC-HPM-MM), which features that its armature windings, magnetizing coils, and U-shaped hybrid PMs are all located in stationary side. Besides, the salient rotor pole exhibits high robustness and simple manufacturing. The low-coercive-force (LCF) PM magnetization state (MS) can be regulated by temporarily applying a current pulse in magnetizing coils, which means that online magnetization variability can be achieved. Due to the consequent-pole hybrid PM arrangement, this new topology exhibits reduced required magnetization current level, good flux concentrated effect, and increased torque capability. The machine topology and operating principle are introduced first. Subsequently, the multi-objective genetic algorithm is adopted to optimize the design parameters of the proposed machine on the basis of optimizing rotor pole number. Finally, the electromagnetic performance of the machine is investigated by finite-element (FE) analysis, which confirms the feasibility of the proposed design.

A solution blending technique was employed to form a nanocomposite film of polyvinyl alcohol modified with carbon nanotube and zinc oxide (CNT/ZnO). The film was characterized using a tensile testing machine, X-ray diffraction, scanning electron microscopy, a contact angle device, and barrier property measurement. When the CNT/ZnO content was 1.2 phr, the results from mechanical property and water vapor permeation tests showed that the nanocomposite film had good tensile strength and water resistance. Moreover, CNT/ZnO improved the hydrophobicity of the film. CNT/ZnO/can improve the performance of PVA and is a good nanofiller of PVA. The results of this research might have the opportunity to be used as packaging film materials in the future.

Parallel fibrous scaffolds play a critical role in controlling the morphology of cells to be more natural and biologically inspired. Among popular tissue engineering materials, poly(2-hydroxyethyl methacrylate) (pHEMA) has been widely investigated in conventional forms due to its biocompatibility, low toxicity, and hydrophilicity. However, the swelling of pHEMA in water remains a major concern. To address this issue, randomly oriented and aligned as-spun pHEMA nanofibrous scaffolds were first fabricated at speeds of 300 and 2000 rpm in this study, which were then post-treated using either a thermal or a freeze-drying method. In cell assays, human dermal fibroblasts (HDFs) adhered to the freeze-drying treated substrates at a significantly faster rate, whereas they had a higher cell growth rate on thermally-treated substrates. Results indicated that the structural properties of pHEMA nanofibrous scaffolds and subsequent cellular behaviors were largely dependent on post-treatment methods. Moreover, this study suggests that aligned pHEMA nanofibrous substrates tended to induce regular fibroblast orientation and unidirectionally oriented actin cytoskeletons over random pHEMA nanofibrous substrates. Such information has predictive power and provides insights into promising post-treatment methods for improving the properties of aligned pHEMA scaffolds for numerous tissue engineering applications.

The monodispersed ultrasmall Fe3O4 nanoparticles (NPs) have been anchored on reduced graphene oxide (rGO) nanosheets through a one-step method. Hybriding Fe3O4 particles with rGO sheets benefits adjusting the permittivity and permeability of the composite, balancing the dielectric loss and magnetic loss. The Fe3O4/rGO composite with a thickness of 3.0 mm exhibits an optimum absorption of − 71.86 dB at a low filler loading of 20 wt%, superior to most Fe3O4/graphene composites. The effective absorbing bandwidth covers 4.1 GHz. These results indicate that the Fe3O4/rGO composites prepared by facile synthesis can be ideal candidates as microwave absorbers with lightweight and excellent microwave absorption properties.

Irradiation of single crystals of a ladder-like coordination chain with 365 nm UV light induces a regiospecific photochemical [2 + 2] cycloaddition reaction of each pair of adjacent diolefinic ligands from neighbouring crystallographically equivalent chains and thus affords a two-dimensional (4,4)-connected coordination network through single-crystal to single-crystal transformation.

Nowadays, although the exploration of proton conductive materials has ranged from traditional sulfonated polymers to novel crystalline solid materials such as MOFs, COFs, and HOFs, research on crystalline cluster-based organic framework materials is very limited. Here, a pair of homologues Cu(I)-based organic framework containing a Cu12S6 cluster, [Cu12(MES)6(H2O)3]n (1) and {[Cu12(MPS)6(H2O)4]·6H2O}n (2) (H2MES = 2-mercaptoethanesulfonate acid and H2MPS = 2-mercaptoethanesulfonate acid), were hydrothermally synthesized under the same conditions and fully investigated for their proton conduction. Their structures were characterized by means of single-crystal X-ray diffraction, elemental analysis, thermogravimetric analyses, and PXRD measurements. The two MOFs show significant structural differences in the topological fashions. MOF 1 has a three-dimensional network and can be simplified into two topology types: a 10-connected gpu structure with a Schlafli symbol (312·426·57) and a 3,12-connected new topology with a point symbol {3·42}2{310·418·519·614·74·9}. MOF 2 also has a three-dimensional framework and topology as a 6-connected pcu primitive cubic network with a Schlafli symbol {412·63}. The two MOFs show different proton conduction parameters, but both indicate temperature-dependent proton conductive features. Intriguingly, the two MOFs exhibit high water stability and their proton conductivities are 3.63 × 10−5 and 2.75 × 10−5 S cm−1 under 333 K and 98% RH, respectively. The suggested mechanism for the synthesis for 1 and 2, and their proton conductivity performance comparison has been discussed in detail. In addition, Hirshfeld surface and fingerprint analysis on the two MOFs were computed to compare contacts between the molecules, which is essential for analyzing the relationships between their hydrogen bonds and proton conductivity properties.

Ti−6Al−4V alloy was fabricated via selective laser melting (SLM) to improve its corrosion resistance for implant. The microstructure and electrochemical corrosion behavior were investigated using scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), transmission electron microscopy (TEM), electrochemical test and contact angle test. It can be found that the as-selective laser melted (as-SLMed) Ti−6Al−4V alloys show β columnar microstructure in building direction and nearly circular checkerboard microstructure in scanning direction, while the wrought and wrought+HT samples exhibit equiaxed microstructure. The as-SLMed Ti−6Al−4V alloy exhibits better corrosion resistance than the wrought and wrought+HT samples due to hydrophobicity, high grain boundary density and uniform distribution of alloying elements in simulated artificial saliva at 37 °C.

In this study, a commercial and low-toxicity hydrazide-containing building block has been used to construct azine-linked covalent organic frameworks (COFs). New style COFs were constructed between flexible formic hydrazide (FH) and 1,3,5-triformylphloroglucinal (Tp) or 1,3,5-triformylbenzene (TFB). The two resulting COFs (TpFH and TFBFH) exhibited uniform hollow tubular morphology (20-50 nm for TpFH, 50-100 nm for TFBFH). Compared to hydrazine, FH has low-toxicity and is a flexible monomer, consisting of amine and aldehyde groups. The decomposition of FH slows down the reaction rate and the as-synthesized FH-series COFs (708 m

The laminar burning velocities (LBVs) and cellular instability of 2-methyltetrahydrofuran (2-MTHF) were investigated at the unburned temperature of 423 K and pressures from 1 to 10 atm in a cylindrical constant-volume vessel. The LBVs of 2-MTHF/air flame exhibit a notably dropping with increasing pressure. The cellular instability analysis indicates that the critical flame radius of 2-MTHF/air mixture monotonically increases with increasing pressure and the flame surface suffers more badly cellularity under higher pressures. The critical flame radius exhibits non-monotonic variation versus ϕ and the most unstable flames appear at ϕ ≈ 1.3. It is observed that the measured Markstein length of 2-MTHF/air mixture decreases with increasing ϕ and Pu, leading to an earlier formation of wrinkling and cracks with respect to preferential-diffusional instability. Further investigation found that by using a mixture of 14.2% oxygen with 85.8% helium in place of air as bath gas at 10 atm can effectively suppress the cellular instability. Two recently developed models were used to simulate the experimental results and explore the chemical kinetic effects on LBV. Reaction path analysis reveals that the most consumption of 2-MTHF/air at stoichiometric conditions is through the abstraction of H-atom to form radical C5H9O-5. While the competitiveness of decomposition by C C scission yielding CH3 and tetrahydrofuran radical is relatively weak. Sensitivity analysis illustrates that small-species reactions show a controlling effect on LBV. The increasing pressure leads to an evident increase in the sensitivity coefficient of the recombination reaction H + O2 (+M)=HO2 (+M). The reduction of H atom concentration will cause competition to the initiation reaction H + O2 = O+OH. This could lower the overall oxidation rate and reduce the burning velocity.

It is of top priority to develop highly efficient visible-light photocatalysts to realize the practical applications of photocatalysis in industry. Niobium pentoxide (Nb2O5) is considered as a potentially attractive candidate for the visible-light-driven photodegradation of organic pollutants. In an effort to enhance its photocatalytic activity, Fe-doped Nb2O5 nanofibers with various Fe contents (the molar ratios of Fe to Nb were 0.005/1, 0.01/1, 0.03/1 or 0.05/1) were successfully prepared by an electrospinning method. The structural features, morphologies, and optical properties of the as-prepared samples were investigated. Photocatalytic activities of the samples were evaluated through degradation of Rhodamine B (RhB) under visible light irradiation. All the prepared Fe-doped Nb2O5 nanofibers exhibited much higher activities for degrading RhB solution than the pristine Nb2O5 nanofibers, and the maximum degradation yield of 98.4% was achieved with the nanofibers (Fe to Nb: 0.03/1) under visible light irradiation for 150 min. The photocatalytic degradation rate fitted a pseudo-first-order equation, and the rate constants of reactions with Fe-doped Nb2O5 nanofiber (the molar ratios of Fe to Nb were 0.03/1) or pure Nb2O5 nanofiber were 0.0282 min−1 and 0.0019 min−1, respectively. Doping Fe ions into the nanofibers enhanced the absorption within the visible-light range and reduced the photo-generated electron–hole pair recombination, and thus improved the photocatalytic activity. These attractive properties suggest that the Fe-doped Nb2O5 nanofibers have great potential for applications in the future to solve pollution issues.

Tandem catalysis, in which a CO2-to-C2 process is divided into a CO2-to-CO/*CO step and a CO/*CO-to-C2 step, is promising for enhancing the C2 product selectivity when using Cu-based electrochemical CO2 reduction catalysts. In this work, a nanoporous hollow Au/CuO–CuO tandem catalyst was used for catalyzing the eCO2RR, which exhibited a C2 product FE of 52.8% at −1.0 V vs. RHE and a C2 product partial current density of 78.77 mA cm−2 at −1.5 V vs. RHE. In addition, the C2 product FE stably remained at over 40% over a wide potential range, from −1.0 V to −1.5 V. This superior performance was attributed to good matching in terms of the optimal working potential and charge-transfer resistance between CO/*CO-production sites (Au/CuO) and CO/*CO-reduction sites (CuO). This site pair matching effect ensured sufficient supplies of CO/*CO and electrons at CuO sites at the working potentials, thus dramatically enhancing the formation rate of C2 products.

Implementation of ammonium halides to trigger low-dimensional perovskite formation has been intensively investigated to achieve blue perovskite light-emitting diodes (PeLEDs). However, the general roles of the incorporated ammonium cations on the quality of the perovskite films, as well as device performance, are still unclear. It is indispensable to build a guideline to rationalize ammonium halides for decent blue emissive films. Here, by thoroughly investigating a series of ammonium cations containing the different number of ammonium groups and ionic radius, we reveal that the mechanism beyond the tunable emission wavelength, crystallization kinetics, and spectral stability of the obtained blue perovskite films is highly relevant to the molecular structure of the ammonium cations. In parallel with reducing the dimensionality to form normal Ruddlesden-Popper phases, the incorporated ammonium cations also likely modulate the Pb-Br orbit coupling through A-site engineering and generate either Dion-Jacobson or "hollow" perovskites, providing alternative routes to achieve efficient and stable blue emissive films. Our work paves a way to rationalize ammonium halides to develop prevailing active layers for further improving the performance of blue PeLEDs.

Here a facile four-electrode electrolysis system is firstly applied to synthesize a CuOx/graphene hybrid. The exfoliation of graphite via high electrolytic voltage and dissolution of copper via low electrolytic voltage are achieved simultaneously. CuOx/G with the highest content of CuOx shows superior electrocatalytic activity for oxygen reduction to hydrogen peroxide.

Constructing intelligent clothing through integrating flexible and wearable electronics in daily clothing has raised the demand for flexible supercapacitors with high energy storage, small thickness and mechanical durability. Herein, a vacuum-filtration assisted layer-by-layer strategy is developed to prepare MXene-based flexible all-in-one supercapacitors. The MXene/carbon nanotube@MnO2 composite film electrode is firstly synthesized by embedding the carbon nanotube@MnO2 nanosheet composite into the interlayer of MXene films. This electrode structure blocks the restacking of MXene nanosheets, leading to a large ion-accessible surface area and efficient ion diffusion pathways. Moreover, the synergistic cooperation of MXene nanosheets and carbon nanotubes forms a 3D conductive network, which avoids the negative influence of MnO2 on the electronic conductivity of electrodes, ensuring a rapid electron transport rate. Benefitting from these advantages, the MXene/carbon nanotube@MnO2 composite film shows a high specific capacity of 221 F g−1, good cycling stability and flexibility. The assembled all-in-one flexible supercapacitor device exhibits a high volumetric energy density and power density of 24.5 mW h cm−3 and 2.5 W cm−3, respectively.

Surface-enhanced Raman spectroscopy (SERS) is a Raman spectroscopy technique that has been widely used in food safety, environmental monitoring, medical diagnosis and treatment and drug monitoring because of its high selectivity, sensitivity, rapidness, simplicity and specificity in identifying molecular structures. This review introduces the detection mechanism of SERS and summarizes the most recent progress concerning the use of SERS for the detection and characterization of molecules, providing references for the later research of SERS in detection fields.

Asymmetric porous cordierite ceramic membranes were fabricated by phase inversion tape casting method. It is shown that the membranes consist of a relatively dense skin layer on the top, a sponge layer at the bottom and a finger-like layer in the middle. The membranes have a hierarchical pore structure, where macrovoids (denoted as dozens-micron-sized (DMS) pores) are present in the finger-like layer and micron-sized (MS) pores are located in the skin layer, sponge layer and the wall of macrovoids. After surface silylation by post-grafting with 1H,1H,2H,2H-perfluorodecyltriethoxysilane (FAS), the sample with a starting powder/polyethersulfone (PESf) weight ratio of 9 (M − 4) becomes hydrophobic, with a water contact angle of 150°. At a NaCl concentration of 3.5 wt%, a feed rate of 18L/h and a feed temperature of 80 °C, the hydrophobic M − 4 membrane exhibits a water permeate flux of 22.33 kg/m2h, which is considerably larger than that of the membranes prepared by dry pressing method previously, and a salt rejection of 99.9%. The higher water permeate flux is attributed to the much lower transport resistance of water vapor in the membranes of the present work.

Engineering the band-edge of photocatalysts is one of the important strategies to adjust the photocatalytic performance. Herein, we successfully prepare Cu-Fe2O3/Ni-ZnO nanoplate photocatalysts and...

The local inhomogeneity of the stir zone in friction stir welded face-centered cubic metal was investigated, which has multiple activated slip systems during plastic deformation, by selecting commercial AA1050 aluminum alloy as an ideal experimental material. The local inhomogeneity was evaluated by uniaxial tensile tests using small samples with a 1 mm gauge length. The corresponding microstructural parameters such as grain size, misorientation angle distribution, and micro-texture, were quantified by the backscattered electron diffraction technique. A comprehensive model was used to reveal the microstructure−mechanical property relationship. The experimental results showed that the uniaxial tensile property changes significantly across the weld. The maximum ultimate tensile strength (UTS) occurred in the center of the stir zone, which was 99.0 MPa. The weakest regions were located at the two sides of the stir zone. The largest difference value in UTS reached 14.9 MPa, accounting for 15% of the maximum UTS. The analysis on the structure−mechanical property relationship suggests that the micro-texture change with the location formed during the rotational material flow is the main reason for the local inhomogeneity.

These days, there is a great demand for the development of orange-red phosphors for temporary applications in the sides of lighting and display. In this work, we synthesized a fresh type of orange-red phosphor with K5Y(P2O7)2-doped Sm3+ by high-temperature solid-state method, and used powder X-ray diffraction (XRD) method to study the crystal structure of prepared samples. Due to the 4f → 4f transition of Sm3+, when excited by near-UV light at 402 nm, K5Y(P2O7)2:Sm3+ phosphor emits orange-red light. The optimized Sm3+ concentration was found at 12%. Because of the concentration quenching, further increasing the Sm3+ concentration will reduce the intencity. The concentration quenching is originated from dipole–dipole interaction between Sm3+ ions. At 200 °C, the relative luminescence intensity is still about 70.3% of the intensity at 25 °C, meaning that K5Y0.88Sm0.12(P2O7)2 has good thermal stability. The chromaticity coordinates CIE were calculated to be (0.5813, 0.416), corresponding to orange-red color. All these results suggest that K5Y0.88Sm0.12(P2O7)2 is a promising orange-red phosphor.

Two dissimilar steel plates, structural steel and mild steel, were joined by explosion welding to form a composite. The composite was then heat-treated by quenching at 840°C for 30 min followed by tempering at 200°C for 3 h. The microstructure was investigated under an optical microscope and a scanning electron microscope. The mechanical properties were measured using Vickers microhardness and Charpy impact tests. The results show a deformed interface with typical wave features at the welding zone, but no defects were observed. Moreover, the ferrite in the parent plate in the weld zone was elongated due to the strong plastic deformation from the explosion. After heat treatment, the hardness of the flyer plate (structural steel) was over HV0.2 800, while that of the parent plate (mild steel) was HV0.2 200. The increase in hardness was due to the presence of martensite. Moreover, the average impact energy was increased from 18.5 to 44.0 J following heat treatment; this is because of the formation of recrystallized grains at the weld interface, which is due to the dynamic recovery and local recrystallization, and the strong elemental diffusion that occurred between the two plates.

Great progress in modification and optimization of emission layer (EML) in perovskite light-emitting diodes (PeLEDs) results in a significant improvement in device efficiency. However, so far, less attention has been paid to the exploration of hole/electron injection and transporting layers to maximize the utilization of charge carriers for efficient and stable PeLEDs. At present, low electron mobility of electron transport layer (ETL) causes an unbalanced charge injection, and the defects at the ETL/perovskite interface limit the formation and utilization of generated excitons. Here, a series of compounds (BPBiTP, BPBiPN, and BPBiPA) flanked by diphenyl-1H-benzo[d]imidazole end groups have been developed as ETL materials, where the bridging units (benzene, naphthalene, anthracene) are manipulated to achieve dual functionality, namely, the high charge carrier mobility and effective passivation of perovskite surface. The coordinating end groups effectively reduce the trap state at the interface of ETL and EML due to their strong nucleophilic quality. H-aggregation of anthracene units and large transfer integral in BPBiPA lead to its superior electron mobility of 8.4 × 10-4 cm2 V-1 s-1 in the solid state, over 1 order of magnitude higher than that of the typical one (TPBi). Consequently, green PeLEDs with a maximum external quantum efficiency (EQE) of 19.7%, reduced efficiency roll-off, as well as extended operational lifetime have been achieved without any outcoupling technique. Our result demonstrated that optimization of ETL materials via improving both passivation capability and electron mobility is a powerful strategy for producing high-performance PeLEDs.

Unbalanced charge injection is one of the major issues that hampers the efficiency of perovskite light-emitting diodes (PeLEDs). Through engineering the device structure with multiple hole transport layers (HTLs), i.e., poly(9,9-dioctyl-fluorene-co-N-(4-butylphenyl)diphenylamine) (TFB)/poly(9-vinylcarbazole) (PVK) and nickel oxide (NiOx)/TFB/PVK, efficient PeLED devices have been successfully demonstrated. However, in a typical solution-processed PeLED with multiple HTLs, the underlying conjugated HTL could be easily redissolved by the ink of the following one, which not only dramatically deteriorates the electrical property of HTLs but also influences the quality of the top perovskite films. In this work, through inserting a thin atomic layer-deposited aluminum oxide (Al2O3) layer between HTLs and the perovskite layer, an improved interfacial contact can be achieved, which enables us to obtain perovskite films with enhanced characteristics and balanced charge injection in the resultant PeLEDs. In addition, because of the proper refractive index (r), the presence of the Al2O3 layer also favors the light out-coupling of PeLEDs. As a result, we fabricate green PeLEDs with good repeatability and external quantum efficiency of 17.0%, which is approximately 60% higher than that of the control device without Al2O3. Our work provides a promising avenue to enhance interfacial contact between the charge transport layer and perovskite for efficient perovskite-based optoelectronic devices.

Activating the inert basal planes of layered molybdenum disulfide (MoS2) is critical to deliver its high hydrogen evolution reaction (HER) efficiency. Herein, oxygen-incorparated MoSx with abundant undercoordinated Mo atoms is fabricated by a facile solvothermal procedure, which realizes synergistically structural and electronic regulations of MoS2 inert basal planes. Experiment results reveal that oxygen incoparation can effectively modulate the electronic structure and further optimize the intrinsic conductivity, while the defect-rich structure with abundant undercoordinated Mo atoms increases the number of active sites. Moreover, the influence of solvothermal temperature on activity of MoS2-x is also investigated. The achieved MoSx electrocatalyst prepared at 220 °C exhibits a superior activity for HER with a low overpotential of 191 mV at 10 mA cm−2, a small Tafel slope of 67 mV dec−1, and an excellent stability due to the largest surface area and superior conductivity.

For a multistream tundish, the uniformity among the streams plays a significant role in the quality of molten steel. How to analyze the uniformity quantitatively and optimize structures of a multistream tundish is an important research content for a multistream tundish. A new approach was proposed to quantify the uniformity among the streams. And a physical study and a numerical study were carried out to optimize the structure of the diversion hole based on the prototype of a six-stream tundish in a steel plant. On the basis of average residence time, the uniformity of each flow was considered fully and then the optimal structure of the diversion hole was obtained by means of the comprehensive analysis of temperature field and velocity field. The results show that the optimum structural parameters adopted for diversion holes are height of 20 mm, angle of 15° and diameter of 80 mm.

In this paper, a novel approach for designing tapered periodic meta-surfaces (TPMS) is proposed for suppressing electromagnetic scattering from a trailing edge of a square metallic plate with a given thickness. The TPMS is realized by periodic square metallic patches with tapered dimensions at the direction perpendicular to the considered edge but keeping its period unchanged. Based on the geometric phase interaction, the mechanism of suppressing electromagnetic scattering is analyzed. The lossy material is not required in this design, so it doesn’t generate thermal energy and benefits infrared stealth of military objects. The backscattering properties from the trailing edge with the proposed TPMS loading are analyzed and compared with that of original trailing edge. It is observed that wide angular trailing edge scattering suppressing can be obtained and the average value of mono-static radar cross section (RCS) reduction is 10 dB for L-band, S-band and C-band. Finally, the bi-static RCS properties and energy distribution of the proposed structure are also proposed to explain the mechanism of the electromagnetic scattering suppression of the trailing edge employed with the TPMS.

With the increasing integration of electronic devices, there are growing demands for excellent thermal conductivity of thermal management materials on account of severe heat accumulation in practic...

Creatively constructing Z-scheme composites is a promising and common strategy for designing effective photocatalyst systems. Herein, we synthesized Z-scheme Fe2O3@Ag-ZnO@C heterostructures from the Fe-MOFs and applied it to photodegradation of tetracycline and methylene blue pollutants in wastewater. The optimized sample exhibits a remarkable performance as well as stability under visible light irradiation. The calculating and experimental results demonstrate that the Fe2O3@ZnO nanointerface and carbon sheath together boost the transfer efficiency of photogenerated carriers and absorption ability, thereby improving the photocatalytic activity. Furthermore, detailed mechanism investigation reveals the pivotal role of reactive oxygen species (•OH and •O2-) generated, resulting in remarkable performance. In addition, cell biology experiments reveal that the wastewater after photocatalytic treatment has good biological compatibility, which is important for applications. This work provides valuable information for constructing high-performance Z-scheme photocatalysts from MOFs for environmental treatment.

Recently, rare-earth-activated phosphors have been excessively studied for applications in field of white light-emitting diodes (W-LEDs). In this work, a series of Sm3+-doped Na5Bi(P2O7)2 phosphors have been synthesized via traditional high-temperature solid-state reaction method. The purity and phase structure were verified by powder X-ray diffraction (XRD) analysis. Owing to the 4G5/2→6H7/2 transition of Sm3+, Na5Bi1−xSmx(P2O7)2 phosphors show intense orange–red emission centered at 600 nm under near-UV light (403 nm) excitation. The 4% Sm3+ ion is the optimum doping concentration. The concentration quenching dominant mechanism is the d−d interaction. Moreover, phosphors Na5Bi0.96Sm0.04(P2O7)2 show good thermal stability, restraining 79.4% at 150 °C of that measured at 25 °C. The CIE coordinates of phosphor Na5Bi0.96Sm0.04(P2O7)2 were calculated to be (0.573, 0.414). Therefore, phosphor Na5Bi1−xSmx(P2O7)2 could be potentially used as an orange–red phosphor for W-LEDs.

The influence of cement raw meal on the NO reduction by biomass char at a high temperature of 900 °C with four O2 concentrations of 1%, 3%, 5% and 8% was investigated in a laboratory scale fixed bed quartz reactor. The results showed that the cement raw meal had certain positive effect on NO reduction by biomass char which promotes dissociation adsorption of NO with the help of CO consumption and oxygen transferred to carbon surface, however, it also shows some negative effect, and the degree depends on O2 concentration. A long-time and high NO reduction rate was obtained in the case of 1% O2 concentration.

Calcium silicate hydrate gel (CSH) was synthesized by calcium acetate and sodium silicate. The structure and morphology of CSH were characterized by X-ray diffraction analysis, Fourier transform infrared spectroscopy and Scanning electron microscopy. The adsorption performance of CSH was measured by static adsorption method. The results show that CSH has porous structure and large specific surface area, and the optimum reaction conditions is the reaction temperature of 25°C and calcium-silicon ratio of 1.2. It has the maximum adsorption capacity of more than 150 mg/g and the removal rate of more than 86% with Cu2+. And it shows the excellent adsorption performance, even when the concentration of Cu2+ is less than 200mg/L, the removal rate is above 90%. The research may provide a low-cost and high-efficiency adsorbent.

In order to deal with the pollution of NO in cement kiln exhaust, the study of NO catalytic decomposition catalyst obtained much more attention. The effect of silica-alumina ratio on NO decomposition rate in cement kiln without other reductant was studied. The NO decomposition rate of catalysts with different silica-alumina ratio was determined by infrared spectrometer. And pore structures and the microstructure of the catalyst were characterized separately by BET surface area, nitrogen adsorption-desorption and XRD. The results show that silica-alumina ratio of catalyst was preferred to be 50 with the best NO decomposition rate when the temperature was below 300 °C. The catalyst with silica-alumina ratio of 60 has the higher catalytic activity when the temperature was higher than 300 °C, and the decomposition rate achieved 70% at 600 °C. XRD results shows the crystallinity of catalysts increased as the silica-alumina ratio increased. BET surface area and the cumulative pore volume of catalysts gradually increased, and the average pore diameter gradually reduced with the increase of silica-alumina ratio.

The organic/inorganic hybrid sol was prepared by hydrolysis polymerization of methyl-triethoxysilane (MTES) with acidic silica sol. Zirconium silicate, zircon sand and refractory fiber were respectively added to the hybrid sol to increase the stability of the coating in high temperature service. P-type skutterudite(SKD) protective coating obtained by multi-layer coating and certain pretreatment. Protective effect was studied by observing the diffusion of antimony from the SKD into the coating. The results show that the coating has the advantages of simple process and high strength and high stability after aging. The sublimation of antimony is suppressed and it is expected to be applied to the protection of SKD in vacuum.