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Funder: Edinburgh Napier University; Id: http://dx.doi.org/10.13039/501100001292, Funder: China Scholarship Council; Id: http://dx.doi.org/10.13039/501100004543, Sodium (Na) is the most appealing alternative to lithium as an anode material for cost-effective, high-energy-density energy-storage systems by virtue of its high theoretical capacity and abundance as a resource. However, the uncontrolled growth of Na dendrites and the limited cell cycle life impede the large-scale practical implementation of Na-metal batteries (SMBs) in commonly used and low-cost carbonate electrolytes. Herein, the employment of a novel bifunctional electrospun nanofibrous separator comprising well-ordered, uniaxially aligned arrays, and abundant sodiophilic functional groups is presented for SMBs. By tailoring the alignment degree, this unique separator integrates with the merits of serving as highly aligned ion-redistributors to self-orientate/homogenize the flux of Na-ions from a chemical molecule level and physically suppressing Na dendrite puncture at a mechanical structure level. Remarkably, unprecedented long-term cycling performances at high current densities (≥1000 h at 1 and 3 mA cm-2 , ≥700 h at 5 mA cm-2 ) of symmetric cells are achieved in additive-free carbonate electrolytes. Moreover, the corresponding sodium-organic battery demonstrates a high energy density and prolonged cyclability over 1000 cycles. This work opens up a new and facile avenue for the development of stable, low-cost, and safe-credible SMBs, which could be readily extended to other alkali-metal batteries.

Up-conversion luminescence materials, such as NaYF4: Yb3+, Er3+ (Tm3+), have very promising application prospects in the biomedical field and have attracted continuous interest in recent years. However, their low up-conversion luminescence performance is still one of the key obstacles to their application. Herein, we have developed a simple and environment-friendly strategy to enhance the up-conversion luminescence of NaYF4: Yb3+, Er3+ (Tm3+) by combining carbon dots (CDs), which were obtained using a wheat straw as the starting material. This luminescence enhancement strategy was effective for different doping ions (NaYF4: Yb3+, Er3+ and NaYF4: Yb3+, Tm3+), different phase structures (cubic and hexagonal) and different morphologies (nanosphere, rod-like, and tube-like). The emission intensities at 539 nm increased around 322 times for tube-like CD@NaYF4: Yb3+, Er3+, 63 times for rod-like CD@NaYF4: Yb3+, Er3+, and 20 times for nanospherical CD@NaYF4: Yb3+, Er3+ compared with that of NaYF4: Yb3+, Er3+ without CDs. The mechanism of luminescence enhancement is probably due to the decrease in defects and the electron capture by CDs and transfer to the lower energy levels of Er3+ or Tm3+ ions.

When compressed in a matrix of solid hydrogen, many metals form compounds with increasingly high hydrogen contents. At high density, hydrogenic sublattices can emerge, which may act as low-dimensional analogues of atomic hydrogen. We show that at high pressures and temperatures, ruthenium forms polyhydride species that exhibit intriguing hydrogen substructures with counterintuitive electronic properties. Ru3H8 is synthesized from RuH in H2 at 50 GPa and at temperatures in excess of 1000 K, adopting a cubic structure with short H–H distances. When synthesis pressures are increased above 85 GPa, we observe RuH4 which crystallizes in a remarkable structure containing corner-sharing H6 octahedra. Calculations indicate this phase is semimetallic at 100 GPa.

The development of hematite-based electrocatalysts (EC) and photoelectrocatalysts (PEC) for oxygen evolution reaction (OER) is highly promising on account of the low-cost and favorable chemical properties. Herein, we report a unique inverse opal framework hematite-based bi-functional catalyst for both EC and PEC water oxidation in alkaline media. Under the combined action of oxygen vacancies (Vo) and gold nanostars (AuNSs) on hematite, the catalyst exhibited excellent activity and stability on both EC and PEC. The composite showed superior electrocatalytic performance for OER with a low overpotential of 281 mV at 10 mA cm−2. Density functional theory (DFT) studies reveal that the coverage of Vo controls the d-band center of surface Fe sites, and the OER activity displays a volcano relationship with the Vo coverage. The addition of gold nanoparticles on the hematite with low Vo coverage improves the adsorption strength of oxygen-containing intermediates to the optimal point and increases the OER activity. Furthermore, the as-prepared photoanode exhibits a ∼3.13 fold increase in current (1.46 mA cm−2) at 1.23 V versus RHE. It is proposed that Vo promotes bulk conductivity and surface catalysis and exhibits reduced activation energy under high light intensity. AuNSs efficiently inhibits the bulk recombination and improves carrier concentration because of the Fermi level equilibration and plasmonic resonance, and the surface catalysis compensates the deterioration of interfacial recombination of carriers induced by Vo, playing a synergistic role.

Automobile side door glass squeaks and rattles during use. This abnormal noise can make the driver and occupants irritable and reduce the comfort of the automobile. This reduces the sales of this automobile. This paper analyzes and determines the cause of squeak and rattle during the lifting and lowering process of the side door glass of an automobile. The noise is due to four reasons. One is that the distance between the inner waterproof belt and the automobile side door glass of the automobile is unreasonable, causing excessive friction between the automobile side door glass and the inner waterproof belt during the automobile side door glass up and down movement. Other factors affecting squeak and rattle may be the distance between the automobile side door sheet metal and the automobile side door glass, the thickness of the automobile side door glass and the characteristics of the inner waterproof belt. The first two dimensions are analyzed using the 6 sigma method, and the structure of the inner waterproof belt is improved and the flocking position is adjusted. The squeak and rattle phenomenon is explained using the implicit dynamic analysis method ABAQUS, and the compression load deflection after the installation of the inner waterproof belt is 3–9 N/100 mm. This research completely solves the squeak and rattle problem caused by the up and down movement of the side door glass of the automobile. This research has significance for solving practical engineering problems.

Dendritic-like BiVO 4 :Ag heterostructure was formed in the process of visible light-irradiated photocatalysis using dendritic-like BiVO 4 as photocatalyst, AgNO 3 as additive and photocatalytic degradation of Rhodamine B (RhB) solution as model reaction. In the coexistence of BiVO 4 and AgNO 3 , Ag islands (nanoparticles) could be formed on the surface of dendritic-like BiVO 4 crystals after Ag + ions captured the photo-generated electrons, and hence the BiVO 4 :Ag heterostructure was obtained. The formation of Ag islands can be directly confirmed by TEM technique. The synergistic effect of the formation of BiVO 4 :Ag heterostructure and Ag + ions as electron capture agent leads to prominent improvement of the photocatalytic activity, i.e., the decolor efficiency of the dendritic-like BiVO 4 photocatalysts for degradation of RhB solution was prominently improved from 34.4% to 91.4% under visible light irradiation only for 20 min.

Transition metal nitrides have applications in a range of technological elds. Recent experiments have shown that new nitrogen-bearing compounds can be accessed through a combination of high temperatures and pressures, revealing a richer chemistry than was previously assumed. Here, we show that at pressures above 50 GPa and temperatures greater than 1500 K the elemental copper reacts with nitrogen forming copper diazenide (CuN2). Through a combination of synchrotron X-ray diraction and first-principles calculations we have explored the stability and electronic structure of CuN2. We find that the novel compound remains stable down to 25 GPa before decomposing to its constituent elements. Electronic structure calculations show that CuN2 is metallic and exhibits partially lled N2 antibonding orbitals, leading to an ambiguous electronic structure between Cu+/Cu2+. This leads to weak Cu-N bonds and the lowest bulkmodulus observed for any transition metal nitride.

Rare earth ions (Tb3+, Eu3+) doped CaWO4 microstructures were synthesized by a facile hydrothermal route without using any templates and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) spectrum. The results indicate that the asprepared samples are well crystallized with scheelite structure of CaWO4, and the average diameter of the microstructures is 2∼4 μm. The morphology of CaWO4:Eu3+ microstructures can be controllably changed from microspheres to microflowers through altering the doping concentration of Eu3+ from 3% to 35%, and the microflowers are constructed by a number of CaWO4:Eu3+ nanoflakes. Under the excitation of UV light, the emission spectrum of CaWO4:Eu3+ is composed of the characteristics emission of Eu3+ 5D0-7FJ (J = 1, 2, 3, 4) transitions, and that of CaWO4:Tb3+ is composed of Tb3+ 5D4-7FJ (J = 6, 5, 4, 3) transitions. Both of the optimal doping concentrations of Tb3+ and Eu3+ in CaWO4 microstructures are about 5%.

It is well known that the bubble dynamics and load characteristics of cavitation bubbles depend to a great extent on their proximity to the boundary. The purpose of this study is to explore the relationship between the boundary curvature and bubble dynamics, as well as the load characteristics, and summarize the relevant change laws. This study takes three hemispheres of different curvatures and one flat board as its main research boundaries. The hemisphere was chosen as the curved surface boundary because the hemisphere represents the simplest type of curved surface boundary. This method allowed us to easily observe the experimental results and summarize the change laws of bubble dynamics and load characteristics. A high voltage electricity of 400 V was used to produce stable and repeatable electric spark bubbles in this experiment. Since the pulsation time of the bubbles is very short, we used a high-speed camera to acquire the necessary photographs. We also used a Hopkinson bar (HPB) to measure the bubble collapse load. Suppose that the dimensionless parameter of curvature is &zeta, and the dimensionless parameter of the explosion distance is &gamma, By summarizing the 44 groups of the experimental results under different combinations of &zeta, and &gamma, we found that the cavitation bubble dynamics and loading characteristics are affected by &zeta, With an increase of &zeta, the shockwave load and bubble collapse load will decrease. In addition, in terms of load characteristics, this study further verified the change trend of the shockwave load and bubble collapse load with &gamma, For the bubble shrink shape, this paper illustrates the relationship between the bubble&rsquo, s shrink shape and its shrinkage speed. Four typical bubble shrink shapes are summarized. The effects of different &zeta, values on the jet are preliminarily explored using the experimental results, and, by considering the experimental results, the developmental trends of the time of the bubble&rsquo, s first pulsation period are discussed.

High pressure can profoundly affect the electronic structure and reactivity, creating compounds between elements that do not react at ambient conditions. Lithium is known to react with gold and silver; however, no copper compounds are known to date. By compressing mixtures of the elements in diamond-anvil cells, compounds of lithium and copper have been synthesized and characterized by X-ray diffraction for the first time. Pressures as low as 1 GPa lead to the formation of a complex layered phase LiCu, displaying two-dimensional kagomé lattice layers of Cu atoms. With increasing pressure, the layered Cu-Cu bonding is replaced by linear chains of Cu atoms in the high-pressure phase Li2Cu. Here we show the powerful effects of even modest pressures on the reactivity of lithium, leading to structures of remarkable complexity and low-dimensional transition metal bonding.

ZnWO4:Eu3+ nanoparticles were prepared via a simple refluxing method, followed by post-deposition annealing at 900 °C for 2 h. Field emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD), and photoluminescence (PL) spectra were used to investigate the morphology, structure and luminescent properties. The spectra of ZnWO4:Eu3+ phosphors were measured in the temperature range of 40–363 K. The broadband emission arises from the intrinsic W O 4 2 − groups, and the characteristic emission of Eu3+ ions increases with temperature increase. As a result, under the excitation at 254 nm, ZnWO4:Eu3+ phosphors emit white light at low temperature and red light at high temperatures, as it can be observed by naked eyes. This can be explained by the different energy transfer efficiency from W O 4 2 − groups to Eu3+ ions in ZnWO4:Eu3+ phosphors at the different temperatures.

Lanthanide doped ZnO mushroom-like 3D hierarchical structures have been fabricated by polyol-mediated method and characterized by various microstructural and optical techniques. The results indicate that the as-prepared ZnO:Ln(3+) (Ln = Tb, Eu) samples have a hexagonal phase structure and possess a mushroom-like 3D hierarchical morphology. The length of the whole mushroom from stipe bottom to pileus top is about 1.0 μm, and the diameters of pileus and stipe are about 0.8 μm and 0.4 μm, respectively. It is found that the flow of N2 is the key parameter for the formation of the novel ZnO structure and the addition of (NH4)2HPO4 has a prominent effect on the phase structure and the growth of mushroom-like morphology. The potential mechanism of forming this morphology is proposed. The pileus of the formed mushroom is assembled by several radial ZnO:Ln(3+) nanorods, whereas the stipe is composed of over layered ZnO:Ln(3+) nanosheets. Moreover, asymmetrical I-V characteristic curves of ZnO:Ln(3+) mushrooms indicate that the texture composition of the 3D hierarchical morphology might lead to the asymmetrical transport behavior of electrical conductivity. Lanthanide doped ZnO samples can exhibit red or green emission under the excitation of UV light.