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Lithium–sulfur (Li–S) batteries are one of the most promising alternatives to lithium–ion batteries because of the advantageous high energy density and low cost. However, the practical applications...

Ferroelectric HfO2-based materials hold great potential for widespread integration of ferroelectricity into modern electronics due to their robust ferroelectric properties at the nanoscale and compatibility with the existing Si technology. Earlier work indicated that the nanometer crystal grain size was crucial for stabilization of the ferroelectric phase of hafnia. This constraint caused high density of unavoidable structural defects of the HfO2-based ferroelectrics, obscuring the intrinsic ferroelectricity inherited from the crystal space group of bulk HfO2. Here, we demonstrate the intrinsic ferroelectricity in Y-doped HfO2 films of high crystallinity. Contrary to the common expectation, we show that in the 5% Y-doped HfO2 epitaxial thin films, high crystallinity enhances the spontaneous polarization up to a record-high 50 µC/cm2 value at room temperature. The high spontaneous polarization persists at reduced temperature, with polarization values consistent with our theoretical predictions, indicating the dominant contribution from the intrinsic ferroelectricity. The crystal structure of these films reveals the Pca21 orthorhombic phase with a small rhombohedral distortion, underlining the role of the anisotropic stress and strain. These results open a pathway to controlling the intrinsic ferroelectricity in the HfO2-based materials and optimizing their performance in applications.

5-Hydroxymethylfurfural (5-HMF), as a key platform compound for the conversion of biomass to various biomass-derived chemicals and biofuels, has been attracted extensive attention. In this research, using Pickering high internal phase emulsions (Pickering HIPEs) as template and functional metal-organic frameworks (UiO-66-SO3H and UiO-66-NH2)/Tween 85 as co-stabilizers to synthesis the dual acid-base bifunctional macroporous polymer catalyst by one-pot process, which has excellent catalytic activity in the cascade reaction of converting cellulose to 5-HMF. The effects of the emulsion parameters including the amount of surfactant (ranging from 0.5 %(mass) to 2.0 %(mass)), the internal phase volume fraction (ranging from 75% to 90%) and the acid/base Pickering particles mass ratio (ranging from 0:6 to 6:0) on the morphology and catalytic performance of solid catalyst were systematically researched. The results of catalytic experiments suggested that the connected large pore size of catalyst can effectively improve the cellulose conversion, and the synergistic effect of acid and base active sites can effectively improve the 5-HMF yield. The highest 5-HMF yield, about 40.5%, can be obtained by using polymer/MOFs composite as catalyst (Poly-P12, the pore size of (53.3 ± 11.3)μm, the acid density of 1.99 mmol·g-1 and the base density of 1.13 mol·g-1) under the optimal reaction conditions (130 ℃, 3 h). Herein, the polymer/MOFs composite with open-cell structure was prepared by the Pickering HIPEs templating method, which provided a favorable experimental basis and theoretical reference for achieving efficient production of high added-value product from abundant biomass.

Electrochemical CO2 reduction (ECR) powered by renewable energy sources provides a sustainable avenue to producing carbon-neutral fuels and chemicals. The design and development of high performance, cost-effective, and stable catalysts for ECR remain a focus of intense research. Here, we report a novel electrocatalyst, two-dimensional cadmium-based 1,4-benzenedicarboxylate metal-organic frameworks (Cd-BDC MOFs) which can effectively convert CO2 to CO with a faradaic efficiency (FE) of more than 80.0% over the voltage range between −0.9 and −1.1 V (versus reversible hydrogen electrode, vs. RHE) in 0.1 mol·L−1 CO2-saturated KHCO3 solution with an H-type cell, reaching up to 88.9% at −1.0 V (vs. RHE). The performance outperforms commercial CdO and many other MOF-based materials demonstrated in prior literature. The catalytic property can be readily tuned by manipulating synthesis conditions as well as electrolyte type. Especially, high CO FEs exceeding 90.0% can be attained on the Cd-BDC electrode at potentials ranging from −0.16 to −1.06 V (vs. RHE) in 0.5 mol·L−1 KHCO3 solution by using a gas diffusion electrode cell system. The maximum CO FE approaches ∼97.6% at −0.26 V (vs. RHE) and the CO partial geometric current density is as high as about 108.1 mA cm–2 at −1.1 V (vs. RHE). This work offers an efficient, low cost, and alternative electrocatalyst for CO2 transformation.

Separation efficiency of photogenerated carriers and CO2 adsorption ability of the catalyst are two important factors affecting the photoreduction performance of CO2. In view of the above analyses, leaf-vein like 2D-1D g-C3N4/P-MWNTs donor/acceptor semiconductor-carbon hybrid composite has been successfully prepared by the simple co-grinding/calcination processes. UV–vis DRS results showed that the modification of P-MWNTs can enhance the photo-absorption ability of the composite. Photoelectrochemical tests proved that 2D-1D Schottky-like barriers can enlarge the separation and transfer efficiency of photogenerated carriers. BET and CO2-adsorption tests exhibited that the introduction of P-MWNTs can greatly increase the CO2 capture ability of the composite. CO2 photoreduction experiments confirmed that the composite had much more excellent CO2 photoreduction performance than the pure g-C3N4 under the irradiation of UV–vis light or visible light. In-situ FTIR and 13C isotope tracer tests were applied to research the CO2 photoreduction processes. Finally, the synergistic effect on CO2 photoreduction process between electron transfer and CO2 adsorption behavior has been discussed in total.

Metal hydrides, generally formed by high pressure combined with high-temperature conditions, have attracted substantial interest due to their promising high-energy density and high-temperature supe...

s SiC nanowires (SiCnws) having different morphologies can be applied to reinforce ceramic materials. However, the in-situ synthesis of SiCnws in ceramic powders, which is critical to ensure satisfactory reinforcement effects, is challenging. To facilitate the reinforcement of ZrB2–ZrC composites, this study proposes a simple method for in-situ fabrication of SiCnws with various morphologies in nanosized ZrB2–ZrC powders by pyrolyzing ZrB2–ZrC–SiC gel precursors. The prepared ZrB2–ZrC ceramic powders had a mean diameter of approximately 100 nm, with uniformly distributed SiCnws having nanocylider, bead-like, bamboo-shape with tuneable nodes, chain-like, and hexagonal prism morphologies prepared by optimizing the preparation process. Moreover, the SiCnws had diameters ranging from 100 to 400 nm, and the length was controlled from tens to hundreds of microns. The generation of ZrB2/ZrC influences the formation of SiCnws with specific morphologies through the production of CO gas, which influences the local supersaturation of the SiO and CO vapours. The findings can provide a basis for fabricating SiCnw-reinforced ceramic materials with an enhanced strengthening effect while ensuring a reasonable fabrication process.

Mineralization of the ZIF-8 in the presence of biomacromolecules has been demonstrated to be a general way for making bioentities@ZIFs composites. The ZIF-8 crystals permit controlled storage and utilization of the bioentities, thus can benefit drug delivery, cold-chain breaking etc. With the increasing needs on personal care and distributed manufacturing, automated synthesis controlled by a computer becomes the next challenge. In this work, we designed an automatic synthesis system to prepare PEG mineralized ZIF-8 composite particles. This system is based on flow chemistry with the microfluidic chips fabricated by femtosecond laser micromachining. The particles were synthesized and monitored automatically. Furthermore, this synthesizer could be extended for fabrication of vaccine particles under remote control through internet.

Alloys present the great potential in catalysis because of their adjustable compositions, structures and element distributions, which unfortunately also limit the fast screening of the potential alloy catalysts. Machine learning methods are able to tackle the multi-variable issues but still cannot yet predict the complex alloy catalysts from the properties of pure metals due to the lack of universal descriptors. Herein we propose a transferable machine-learning model based on the intrinsic properties of substrates and adsorbates, which can predict the adsorption energies of single-atom alloys (SAAs), AB intermetallics (ABs) and high-entropy alloys (HEAs), simply by training the properties of transition metals (TMs). Furthermore, this model builds the structure-activity relationship of the adsorption energies on alloys from the perspective of machine learning, which reveals the role of the surface atoms’ valence, electronegativity and coordination and the adsorbates’ valence in determining the adsorption energies. This transferable scheme advances the understanding of the adsorption mechanism on alloys and the rapid design of alloy catalysts.

Triple cation perovskite photodetectors with different feature bandgaps were stacked and sealed for multi-color fluorescence detection.

Recently in nanophotonics, a rigorous evolution from passive to active metasurfaces has been witnessed. This advancement not only brings forward interesting physical phenomena but also elicits opportunities for practical applications. However, active metasurfaces operating at visible frequencies often exhibit low performance due to design and fabrication restrictions at the nanoscale. In this work, we demonstrate electrochemically controlled metasurfaces with high intensity contrast, fast switching rate, and excellent reversibility at visible frequencies. We use a conducting polymer, polyaniline (PANI), that can be locally conjugated on preselected gold nanorods to actively control the phase profiles of the metasurfaces. The optical responses of the metasurfaces can be in situ monitored and optimized by controlling the PANI growth of subwavelength dimension during the electrochemical process. We showcase electrochemically controlled anomalous transmission and holography with good switching performance. Such electrochemically powered optical metasurfaces lay a solid basis to develop metasurface devices for real-world optical applications.

Combining plasmonic and magnetic properties, namely magneto-plasmonic coupling, inspires great research interest and the search for magneto-plasmonic nanostructure becomes considerably critical. Here we designed a nanopillar-in-matrix structure with core–shell alloyed nanopillars for both BaTiO3 (BTO)-Au0.5Co0.5 (AuCo) and BTO-Au0.25Cu0.25Co0.25Ni0.25 (AuCuCoNi) hybrid systems, i.e., ferromagnetic alloy cores (e.g., Co or CoNi) with plasmonic shells (e.g., Au or Au/Cu). These core–shell alloy nanopillars are uniformly embedded into a dielectric BTO matrix to form a vertically aligned nanocomposite (VAN) structure. Both hybrid systems present excellent epitaxial quality and interesting multi-functionality, e.g., high magnetic anisotropy, magneto-optical coupling response, tailorable plasmonic resonance wavelength, tunable hyperbolic properties and strong optical anisotropy. These alloyed nanopillars-in-matrix designs provide enormous potential for complex hybrid material designs with multi-functionality and demonstrate strong interface enabled magneto-plasmonic coupling along with plasmonic and magnetic performance.

Wide-light absorption performance and efficient carrier separation ability are the necessary conditions for excellent photocatalytic materials. In this research, g-C3N4 QDs (CN QDs) and Au nano-particles (NPs) co-modified CeO2/Fe3O4 micro-flowers (MFs) photocatalyst (CACeF) has been prepared. CO2 photoreduction experiments showed that the composite had obviously enhanced photoreduction activity and photocatalytic stability. The yields of CO and CH4 over it as catalyst in 4 h is about 5 and 8 times greater than that of pure CeO2. Photoelectrochemical tests showed that the heterojunction between CN QDs and Au NPs can greatly improve the carrier separation ability and the light-utilization efficiency of photocatalysts. Besides, the excellent electronic transmission performance of Au NPs provided a specific channel for the electron transmission, and the strong local surface plasmon resonance (LSPR) of Au NPs resulted in a lot of hot-electrons can directly take part in the CO2 photoreduction. The synergistic effect between CN QDs and Au NPs can further enhance the photocatalytic activity of the photocatalyst. Fe3O4 QDs can ensure the effective recovery and reuse of the composite without affecting the photocatalytic performance of composite. Finally, a potential photoreduction mechanism of CN QDs and Au NPs co-modified CeO2/Fe3O4 MFs photocatalyst were discussed in total.

Electrolyte chemistry offers the opportunity to regulate the solid electrolyte interphase (SEI) and Li+ solvation, which is considered to be crucial to the growth of lithium crystals for safe lithium metal batteries (LMBs). Structurally tunable characteristics of ionic liquids (ILs) from anion type, cationic substituent chain length and cationic substituents, will contribute this field. Here, we explore the influence mechanism of imidazole-based ILs as electrolyte additives on Li+ solvation and the formation of SEI. ILs can participate into the formation of efficient SEI, together with cathode electrolyte interphase (CEI). Moreover, ILs can also regulate the sheath structure of Li+ solvation, to fasten the kinetics of Li. Furthermore, the imidazole-based cations with long alkyl chain can form an electrostatic shield around newly formed Li nucleus, and suppress further Li plating at this site. Under the optimized condition, the 1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([OMIm]TFSI) additive shows the best ability to enhance the electrochemical performance, endowing the Li||Li symmetric cell with a stable life (over 800 h) at 0.5 mA cm−2 and the Li||LiNi0.6Mn0.2Co0.2O2 (NMC622) full cell with a high capacity of 141.7 mAh g−1 after 200 cycles at 0.5 C.

At present, superconducting power technology has been applied more and more in the ac field, such as ac superconducting current limiter, ac superconducting cable, and so on. Critical current is the key parameter in the design, manufacture, and operation process of superconducting devices, but few studies were carried out on the ac critical current of superconductors now. In this article, a method for measuring the ac critic al current of the HTS coil based on the thermal stability was proposed, the ac critical current measurement experiment of the superconducting coil is carried out, and the electromagnetic–thermal coupling model is built to analyze the quench principle of the superconducting coil. This article explains the principle of ac critical current from the balance of heating and cooling and gives the rule that the value of ac critical current changes with frequency.

In order to realize high-sensitivity real-time monitoring of acid-base neutral solutions in the industrial field, it is very important to study how to improve the sensitivity of a pH sensor. Herein, the sensitivity of the pH sensor was improved by using both monolithic integrated planar multi-channel and photoconductive properties of gallium nitride (GaN) high electron-mobility transistors (HEMTs) as a core of the pH sensor. The sensitive area of aluminum gallium nitride/gallium nitride (Al $_{0.25}$ Ga $_{0.75}$ N/GaN) heterojunction HEMT channel surface was increased, and the channel effective resistance was reduced by planar multi-channels. And the photogenerated current was generated by 365-nm ultraviolet (UV) light based on the photoconductive effect. This investigation mainly shows as the sensitivity of the tri-channel was 37.04 μA/pH, which increased 30 times compared with that of the single-channel device under the dual action of planar multi-channel and 365-nm UV light coupling in potassium hydrogen phthalate, mixed phosphate, and borax pH correction buffer solutions. The concept of using the GaN HEMT-based pH sensor for direct quantification of pH values in waste water provides a simple and high-performance method for industrial applications.

Background H2O2, as a green and environmentally friendly oxidant, has been widely used in our daily life and industrial production. It is of epoch-making significance to develop highly efficient photocatalysts for producing H2O2. In recent years, g-C3N4 has received much attention due to its high chemical stability, environmental friendliness and suitable energy band structure. However, some shortcomings including the fast recombination of photogenerated electron-hole pairs and small specific surface area in traditional 2D g-C3N4 seriously impede its photocatalytic performance for the production of H2O2. Methods 1D hollow nanostructures possess intriguing physicochemical properties and are adopted to overcome the intrinsic shortcomings of g-C3N4. Herein, g-C3N4 with a hollow hexagonal prism structure (CN HP) is prepared to produce H2O2. It is characterized by XRD, XPS, SEM, HRTEM, ESR and DRS. BET, PL spectra, photocurrent and EIS are used to explain the enhanced photocatalytic performance. Significant findings Compared with traditional 2D g-C3N4, the specific surface area of CN HP increases to 41.513 m2/g, providing more active sites. Meanwhile, its hollow tubular structure can enhance the migration of photogenerated electrons to the catalyst surface, and electrons with a longer lifetime can participate in photocatalytic reactions to achieve high efficiency. The yield of H2O2 production can up to 4.08 μmol over CN HP in 40 min, which is about 7 times higher than that of traditional 2D g-C3N4, and the apparent quantum efficiency (AQE) of H2O2 production at 420 nm is 2.41%. This research provides a valuable reference for the development of green materials for efficient photocatalytic production of H2O2.

Renewable bamboo materials have broad application prospects in the fields of structural construction, insulation and acoustic management due to their multi-layer porous structure, attractive directional layout texture, ultra-fast growth rate, and excellent mechanical strength. However, the annual loss of bamboo material due to the microbial corrosion accounts for one-tenth of the total output. In this work, the hydrophobic associating hydrogel (HAH) with chitosan (CS) and zinc oxide (ZnO) has been in situ filled in the micro-nano-scale pores of natural bamboo materials to significantly enhance their anti-microbial fouling performance. It is difficult for the mildew and oxygen in the air to come into the bamboo materials due to the artificial hydrogel barrier layer. CS and ZnO nanomaterials further increase the anti-bacterial rate of bamboo composites to 100%. Based on the physical crosslinking between the polyacrylamide (PMA) of HAH hydrogel and natural bamboo fibers, CS and ZnO bacteriostatic media are not easy to be lost from the bamboo materials. The 100% anti-bacterial rate of the bamboo composite materials can be maintained for at least 56 days. Therefore, the bamboo composites have great application potential as building materials in the future. In-situ polymerization method was used to fill the micropores of bamboo with super-elastic hydrogel to enhance its anti-microbial fouling performance.

Developing affordable and efficient electrocatalysts as precious metal alternatives toward the hydrogen evolution reaction (HER) is crucially essential for the substantial progress of sustainable H2 energy-related technologies. The dual manipulation of coordination chemistry and geometric configuration for single-atom catalysts (SACs) has emerged as a powerful strategy to surmount the thermodynamic and kinetic dilemmas for high-efficiency electrocatalysis. We herein rationally designed N-doped multichannel carbon nanofibers supporting atomically dispersed Mo sites coordinated with C, N, and O triple components (labeled as Mo@NMCNFs hereafter) as a superior HER electrocatalyst. Systematic characterizations revealed that the local coordination microenvironment of Mo is determined to be a Mo-O1N1C2 moiety, which was theoretically probed to be the energetically favorable configuration for H intermediate adsorption by density functional theory calculations. Structurally, the multichannel porous carbon nanofibers with open ends could effectively enlarge the exposure of active sites, facilitate mass diffusion/charge transfer, and accelerate H2 release, leading to promoted reaction kinetics. Consequently, the optimized Mo@NMCNFs exhibited superior Pt-like HER performance in 0.5 M H2SO4 electrolyte with an overpotential of 66 mV at 10 mA cm-2, a Tafel slope of 48.9 mV dec-1, and excellent stability, outperforming a vast majority of the previously reported nonprecious HER electrocatalysts. The concept of both geometric and electronic engineering of SACs in this work may provide guidance for the design of high-efficiency molecule-like heterogeneous catalysts for a myriad of energy technologies.

There has been recent interest in understanding the transport of nanoconfined fluids through single-digit nanopores (SDNs) or those smaller than 10 nm in diameters, where confinement alters the flu...

Bottom-up construction of highly complex architecture from simple components remains one of the long-standing challenges in chemistry. Herein two supramolecular isomers based on large trigonal prismatic Pd3L16 building block are reported. Significantly, they can be controllably obtained by adjusting the solute concentration during crystal growth. Specifically, the square shape crystals, α-[Pd3L16](PF6)12 in the cubic system with $$I\bar 43m$$ space group, can be isolated from a high-concentration solution of Pd3L16. Interestingly, a mesoporous cage assembled from eight Pd3L16 units with a diameter of 24 A is observed in the crystal structure. For the low-concentration solution of Pd3L16, the rectangular shape crystals β-[Pd3L16](PF6)12 are obtained, which crystallize in the hexagonal system with P63Im space group, and display two-dimension packing pattern and one-dimension mesoporous channels (diameter ca. 22 A) along the c axis. Moreover, the two supramolecular isomers were used as nanoporous reactors to induce the specific formation of polyiodides with different compositions and shapes as evidenced from single crystal X-ray diffraction studies. These findings provide a reference in targeting functional crystalline mesoporous supramolecular materials from a single complex building unit.

Understanding the structural behavior of double perovskites plays a pivotal role in optimizing their optical, electrical, and magnetic properties, especially when the effects of external parameters...

Organic solar cells are a current research hotspot in the energy field because of their advantages of lightness, translucency, roll to roll printing and building integration. With the rapid development of small molecule acceptor materials with high-performance, the efficiency of organic solar cells has been greatly improved. Further improving the device efficiency and stability and reducing the cost of active layer materials will contribute to the industrial development of organic solar cells. As a novel type of carbon nanomaterials, carbon dots gradually show great application potential in the field of organic solar cells due to their advantages of low preparation cost, non-toxicity and excellent photoelectric performance. Firstly, the synthesis and classification of carbon dots are briefly introduced. Secondly, the photoelectric properties of carbon dots and their adjusting, including adjustable surface energy level structure, good film-forming performance and up/down conversion characteristics are summarized. Thirdly, based on these intrinsic properties, the feasibility and advantages of carbon dots used in organic solar cells are discussed. Fourthly, the application progress of carbon dots in the active layer, hole transport layer, electron transport layer, interface modification layer and down-conversion materials of organic solar cells is also reviewed. Finally, the application progress of carbon dots in organic solar cells is prospected. Several further research directions, including in-depth exploration of the controllable preparation of carbon dots and their application in the fields of interface layer and up/down conversion for improving efficiency and stability of device are pointed out.

The primary problem that must be overcome when preparing high-performance SiC/Al composites for electronic packaging is how to effectively suppress the harmful SiC/Al interfacial reaction and thereby optimize interface bonding. Preoxidation of the SiC surface is an efficient and widely used method for this purpose. In this study, impregnation and inconsecutive oxidation methods were used to investigate the interfacial reaction between pure Al and SiC that was preoxidized under different conditions. The thickness of the oxide film that formed on the surface of SiC increased when the oxidation temperature was increased or when the oxidation time was extended. The protection of the oxide film isolated the SiC from the molten Al, and the SiC/Al interfacial reaction was effectively suppressed. In the alloy system containing Mg, the formation ratio of Al4C3 to MgAl2O4 at the interface was related to the thickness of the oxide film. The mechanism of the interfacial reaction was analyzed to obtain a theoretical and experimental basis for the preparation of SiC/Al composites to improve their comprehensive properties.

In this work, the time-delay effect on device operation caused by capacitance is studied in terms of phase-change memory (PCM) integrated with an ovonic threshold switch (OTS) selector. The capacitance studied in this work is the intrinsic capacitance associated with capacitive reactance of the PCM itself. The capacitance of the PCM in the amorphous state was measured, and it presents an exponential dependence on voltage bias. Through the simulation model of an OTS-PCM integrated device that considering the measured capacitance behavior, the time-delay characteristics of the integrated device for the SET process with various pulses were investigated. Results indicate that the onset of the threshold switching (TS) is delayed in the PCM but occurs early in the OTS with capacitance in the integrated device. In addition, it is found that the variable capacitance behavior can not only minimize the delay effect, but also accelerate the SET operation under certain conditions in the integrated device. Our results can provide practical guidance for the design of fast operating devices.

The Gleeble-3800 thermal simulator is used to perform isothermal and constant strain rate compression tests on SP700 titanium alloy under the conditions of deformation temperature of 700–950 °C and strain rate of 0.001–1 s−1. The processing map technology can be obtained based on dynamic material model, through this technology, its thermal deformation behavior can be studied and the appropriate processing parameter range can be optimized by combining the changes in the strain rate sensitivity exponent m, strain hardening exponent n and deformation activation energy Q. The results show that the flow stress of SP700 titanium alloy is sensitive to deformation temperature and strain rate. When the strain is 0.9, the strain rate sensitivity exponent m is greater than 0.5 when the deformation temperature is 800 °C and the strain rate is 0.001 s−1 and 1 s−1. Under this condition, the SP700 titanium alloy may have superplastic deformed. In addition, the analysis shows that when the deformation temperature is 775–825 °C, the strain rate is 0.3–1 s−1 and 0.001–0.002 s−1, this condition is the best processing parameter range of SP700 titanium alloy.

In our current study, porous heparin-polyvinylpyrrolidone/TiO2 nanocomposite (HpPVP/TiO2) bandage were prepared via the incorporation of TiO2 into HpPVP hydrogels for biomedical applications such as burn infection. The effect of the HpPVP hydrogels and the nanoparticles of TiO2 composition on the functional group and the surface properties of the as-fabricated bandages were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray diffractometry (XRD). The presence of TiO2 nanoparticles created the internal structure of the HpPVP hydrogel that aids in a homogeneous porous structure, as indicated by the scanning electron microscope (SEM). The size distribution of the TiO2 nanoparticles was measured using a transmission electron microscope (TEM). The studies on the mechanical properties of the HpPVP hydrogel indicate that the addition of TiO2 nanoparticles increases its strength. The prepared HpPVP/TiO2 nanocomposite dressing has excellent antimicrobial activity were tested against bacterial species (Staphylococcus aureus and Escherichia coli) and has good biocompatibility against human dermal fibroblast cells (HFFF2) for biological applications. In addition, in vivo evaluations in Kunming mice exposed that the as-fabricated HpPVP/TiO2 nanocomposite bandages increased the wound curing and facilitated accelerate skin cell construction along with collagen development. The synergistic effects of the HpPVP/TiO2 nanocomposite hydrogel dressing material, such as its excellent hydrophilic nature, good bactericidal activity, biocompatibility and wound closure rate through in vivo test makes it a suitable candidate for burn infections.

The superplastic forming process has been used extensively in aerospace applications for its advantages in manufacture of complicated components. But it has been limited to the long production cycle and the non-uniform thickness distribution of the final formed part. The two-stage SPF process in opposite directions for 5083 aluminum alloy door frames was investigated. A finite element model in PAMSTAMP was used to simulate the forming process. Analyzed the effect of pre-forming die parameters on the minimum thickness of the final formed part by the Response Surface Methodology and optimized the pre-forming die parameters. Moreover, the influence of different rated pressure on the forming quality and forming time of the door frames under the same strain rate were investigated to determine the ideal pressure profile. The result was that the minimum thickness meets the requirements (thinning not exceeding 40%) while reducing the production cycle. Finally, the two-stage superplastic forming experiment in opposite directions was conducted to verify the accuracy of the numerical simulation and produce the door frames with high quality.

In this letter, the triggering efficiency of 1-mm-gap, opposed-contact GaAs Photoconductive Semiconductor Switch (PCSS) is studied in avalanche mode. Compared with the anode-triggered PCSSs, it is found that the cathode-triggered devices are with shorter delay time and lower on-state resistance under the same operation conditions. The delay time jitter of ~45.6 ps is also achieved at the power level of $\sim 4$ MW by cathode triggering. Then the theory of multiple avalanche domains is introduced to interpret the influence of laser spot location on triggering efficiency by a two-dimensional (2D) device simulation. The delay time and on-state resistance are essentially attributed to the formation time and the density of avalanche domains which are affected by the triggering position.

In this work, two aza-BODIPY derivatives, 3,5-diphenyl-1,7-di(p-dodecyloxyphenyl)-aza-BODIPY (CJF) and 3,5-di(p-bromophenyl-1,7-di(p-dodecyloxyphenyl)-aza-BODIPY (2Br-CJF) acted as model molecules to form the self-assembly monolayers on the solid-liquid interface. With the utilizing of scanning tunnelling microscope (STM), we demonstrated that intermolecular Br⋯F BF interactions existed in 2Br-CJF self-assembly structure and played an important role in strengthening the stability of 2Br-CJF self-assembly structure. This result is supported by density functional theory (DFT) calculation.

Die attachment by pressureless silver sintering at I–V characteristics and the thermal resistance of the IGBT modules were discussed.

Twin graphene can introduce stable and extended defects to energy band engineering, giving unique electron transport properties, which is expected to have potential applications in the fields of magnetism, spin transport or photoluminescence. This study proposes a method of using electric-field-assisted temporally-shaped femtosecond laser ablation liquid (ETLAL) of graphene dispersion to prepare graphene quantum dots (GQDs) with an average particle size of 2–3 nm and oxygen-containing functional groups modified surface, which realizes the controllable preparation of single crystal and twin GQDs (5-fold twin). This method controls the crystallinity of GQDs from two aspects: (1) The intervention of an electric field can rapidly command the directional motion of the cavitation bubbles and the nanoparticles contained therein to collide and crystallize at higher temperatures and pressures, which is the key to the formation of twin GQD; (2) Adjusting temporally-shaped femtosecond laser pulse delay could control the proportion of the Coulomb explosion during the ablation process, which increases the carbon cluster supplied by the cavitation bubble which is the key of polyploid number in twin GQDs. This research provides a fast, green strategy for the preparation of unprecedented twin GQDs, which is of great significance to the applications in the field of 2D material defect engineering.

Spider silk-inspired hydrogen-bond (H-bond) cross-linking has recently been shown to enable polymers, e.g., poly(vinyl alcohol) (PVA), to achieve high strength in combination with large ductility a...

Based on volume of fluid (VoF) interface capturing method and shear-stress transport (SST) k-ω turbulence model, numerical simulation was performed to reveal the flow mechanism of metal melts in melt delivery nozzle (MDN) during gas atomization (GA) process. The experimental validation indicated that the numerical models could give a reasonable prediction on the melt flow process in the MDN. With the decrease of the MDN inner-diameter, the melt flow resistance increased for both molten aluminum and iron, especially achieving an order of 102 kPa in the case of the MDN inner-diameter ≤1 mm. Based on the conventional GA process, the positive pressure was imposed on the viscous aluminum alloy melt to overcome its flow resistance in the MDN, thus producing powders under different MDN inner-diameters. When the MDN inner-diameter was reduced from 4 to 2 mm, the yield of fine powder (

We have theoretically investigated the effect of front electrode on the structure and performances of Ga x In $_{1-{x}}$ As y Sb $_{1-{y}}$ thermophotovoltaic (TPV) cells. By sampling a comb-like electrode, it is clearly demonstrated here that the optimum grid separation ${d}_{G}$ depending on the cell bandgap yields a quadratic function for a given spectrum illumination, while the desired coefficients are strongly temperature-dependent and can be well modeled by an exponential decay expression. Comparing with previous report with constant grid separation, the denser front electrode promises an inferior cell efficiency, but the similar phenomenological method can be still applicable to predict the structure and performance of Ga x In $_{1-{x}}$ As y Sb $_{1-{y}}$ TPV cells for a given operation environment.

The axial compressive behavior of laminated bamboo lumber (LBL) columns with a chamfered section was investigated using 15 specimens with lengths varying from 600 mm to 3000 mm; all considered samples had same square cross section of 100 mm × 100 mm with 10 mm chamfers at each corner. Axial compression tests were carried out to analyze the impact of slenderness ratios on failure modes, strain and ultimate bearing capacity of LBL columns. Two failure modes were observed i.e. compression failure and buckling failure. Obtained results on the ultimate vertical strain and ultimate load showed a downward trend with the increase in slenderness ratios; the correlation between the ultimate strain, ultimate load and the slenderness ratios were fitted. The approximate solution method was adopted to reveal the lateral deflections of buckling columns by a quartic functional model. Based on the ideal elastic–plastic constitutive model and Hill failure criterion, FEM was carried out to simulate the axial compression tests. The simulation results agreed well with both test and theoretical results, which verified the feasibility of proposed methods used under similar working conditions in this paper.

In this study, the microstructure and defect characteristics of flash sintering under direct current (DC) and alternating current (AC) were investigated and compared for the ZnO system. DC flash sintering resulted in grain size and porosity gradients within the sample, whereas AC flash sintering produced a sample with homogeneous and fine grain size. Raman spectroscopy revealed asymmetric peaks correlated to the lattice disorder. Using the Breit-Wigner-Fano model, the asymmetric peak fitting revealed redistribution of defects within the DC flash sintered ZnO, while the AC flash sintered ZnO had a comparable defect concentration to conventionally sintered ZnO.

In this article authors present a prototype of a dichroic scanning nonlinear optical microscope with a photodetecting polymer Scanner and a customized objective lens with an external back focal plane. Two types of two-axis electromagnetic actuated polymer scanners are manufactured by a standard printed circuit board (PCB) fabrication process. Both scanners share the same overall dimensions of 45 mm by 45 mm. The maximum optical scan angle of a type I scanner is 13 degrees at 420 Hz by the fast axis in resonance and 4 degrees by the slow axis in the linear mode. The type II scanner shows similar performance. A scan lens as well as a tube lens in a conventional nonlinear optical microscope are replaced by placing such a polymer scanner on the external back focal plane of a customized water immersion objective lens. The objective lens has the back working distance of 6 mm, the numerical aperture of 0.7, the front working distance of 1.16 mm, a field of view of 1.67 mm in the diameter and the angle of view of +/−15 degrees. Preliminary imaging results are also presented.

DNA origami can be applied as a "ruler" for nanoscale calibration or super-resolution fluorescence microscopy with an ideal structure for defining fluorophore arrangement, allowing the distance between fluorophores to be precisely controlled at the nanometer scale. DNA origami can also be used as a nanotag with arbitrary programmable shapes for topological identification. In this study, we formed a hexagonal origami structure embedded with three different fluorescent dyes on the surface. The distance between each fluorescent block was ~120 nm, which is below the diffraction limit of light, allowing for its application as a nano-ruler for super-resolution fluorescence microscopy. The outside edge of the hexagonal structure was redesigned to form three different substructures as topological labels. Atomic and scanning force microscopy demonstrated the consistent nanoscale distance between morphological and fluorescent labels. Therefore, this fluorophore-embedded hexagonal origami platform can be used as a dual nanoruler for optical and topological calibration.

Cross-laminated timber (CLT) is produced from renewable bio-composite material and has been gaining popularity in building industry largely due to easily customised panellised construction technique, which is fast, efficient, minimises construction risk and waste. CLT is often considered as a sustainable alternative to traditional construction materials, and can be used to complement steel and concrete to build a sustainable future. CLT is reported to provide excellent resistance against both out-of-plane and in-plane loading but rolling shear properties have been recognized as one of the critical parameters that often controls the design resistance when CLTs are subjected to out-of-plane loading scenario. Rolling shear characteristics are highly dependent on wood species, sawing patterns and width-to-thickness ratio (wl/tl) of a single lamella. This paper presents a thorough investigation on rolling shear properties of two types three-layer CLT panels (CL3/105 and CL3/135) produced by XLam from Australian Radiata Pine. Rolling shear properties were measured using two test methods i.e. short-span four-point bending test and planar shear test. Typical rolling shear failures were observed in samples tested using short-span bending method and rolling shear stresses were evaluated by using various analytical methods. Planar shear samples also failed in rolling shear, as expected, and showed comparable results. Existing theoretical approaches were used to evaluate the rolling shear properties with a characteristic rolling shear strength of 2.0 MPa and shear modulus of 65.5 MPa for the considered Radiata Pine CLT panels. In addition, an empirical equation has been proposed based on the rolling shear results for other similar species published in literature and the current observations were compared against the proposed equation.