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Platinum (Pt) is the most effective bench-marked catalyst for producing renewable and clean hydrogen energy by electrochemical water splitting. There is demand for high HER catalytic activity to achieve efficient utilization and minimize the loading of Pt in catalysts. In this work, we significantly boost the HER mass activity of Pt nanoparticles in Pt x /Co to 8.3 times higher than that of commercial Pt/C by using Co/NC heterojunctions as a heterogeneous version of electron donors. The highly coupled interfaces between Co/NC and Pt metal enrich the electron density of Pt nanoparticles to facilitate the adsorption of H + , the dissociation of Pt-H bonds and H 2 release, giving the lowest HER overpotential of 6.9 mV vs. RHE at 10 mA/cm 2 in acid among reported HER electrocatalysts. Given the easy scale-up synthesis due to the stabilization of ultrafine Pt nanoparticles by Co/NC solid ligands, Pt x /Co can even be a promising substitute for commercial Pt/C for practical applications.

To solve the problem of measuring the combustion temperature of hydrogen gas, an improved two-colour pyrometer with suspended tungsten powder was developed and calibrated by a tungsten halogen lamp. The characteristic temperature parameters of the premixed 30% H2/70% air flame, including temperature distribution, proportion, maximum value, minimum value, and average value, could be measured and calculated using the improved two-colour pyrometer method and a python code. The temperature measuring results of H2-air mixture obtained by this technique were compared with that of thermocouples and previous studies. The results verified its feasibility to measure the flame temperature structure of H2 combustion. Future work concerning the influential factors of the improved two-colour pyrometer was also mentioned.

Hepatocellular carcinoma (HCC) has attracted worldwide attention due to its extremely high mortality rate. Early diagnosis is conducive to the remission and recovery of patients' symptoms and has become one of the effective methods to reduce the mortality rate. Surface-enhanced Raman scattering (SERS) participating in immune analysis has become a popular research method for early diagnosis of HCC in recent years. In this article, a large amount of Ag deposited on one side of the rod top causes it to be constructed into a bent rod array structure. Finite-difference time-domain simulation of the bent rod arrays proves the variation of the flatness at the top of the rods and the gap caused by the bending of the rod are the main reasons for the changes of the SERS signal intensity. The Raman shift in the characterization results of antigen-captured immunochip has become the important information to quantify the α-fetoprotein content of HCC marker. The bent rod array can be considered as an excellent immunochip in SERS spectroscopy and has a good application prospect as a biosensor.

NOx- reduction acts a pivotal part in sustaining globally balanced nitrogen cycle and restoring ecological environment, ammonia (NH3) is an excellent energy carrier and the most valuable product among all the products of NOx- reduction reaction, the selectivity of which is far from satisfaction due to the intrinsic complexity of multiple-electron NOx--to-NH3 process. Here, we utilize the Schottky barrier-induced surface electric field, by the construction of high density of electron-deficient Ni nanoparticles inside nitrogen-rich carbons, to facilitate the enrichment and fixation of all NO x - anions on the electrode surface, including NO 3 - and NO 2 - , and thus ensure the final selectivity to NH 3 . Both theoretical and experimental results demonstrate that NO x - anions were continuously captured by the electrode with largely enhanced surface electric field, providing excellent Faradaic efficiency of 99 % from both electrocatalytic NO 3 - and NO 2 - reduction. Remarkably, the NH 3 yield rate could reach the maximum of 25.1 mg h -1 cm -2 in electrocatalytic NO 2 - reduction reaction, outperforming the maximum in the literature by a factor of 6.3 in neutral solution. With the universality of our electrocatalyst, all sorts of available electrolytes containing NO x - pollutants, including seawater or waste water, could be directly used for ammonia production in potential through sustainable electrochemical technology.

The microstructure and magnetic properties of alloy Fe78Co2Zr8Nb2B9Cu1 obtained by single roll melt spinning are studied after annealing at 550, 600 and 650°C for different times. In the case of annealing below 650°C the amorphous matrix contains only precipitates of phase α-Fe(Co). After the annealing at 550°C the specific saturation magnetization increases with the duration of the annealing; after the annealing at 600 and 650°C for over 30 min it remains the same.

Crossflow instability (CFI) is crucial for triggering boundary-layer flow transition over a transonic natural laminar flow (NLF) wing, whose leading edge is swept for reducing wave drag. This paper...

A Dielectric Barrier Discharge (DBD) plasma actuator can create a body force which locally accelerates the base flow leading to an attenuation of broadband disturbance to delay the transition. In this study, numerical simulation on an NLF0416 airfoil is conducted to investigate transition delay and drag reduction by a DBD plasma actuator. To simulate plasma’s effect more accurately, boundary-layer data is acquired from Reynolds Averaged Navier Stocks (RANS) equations instead of laminar boundary layer equations, although RANS equations need a much finer boundary-layer grid, and the linear stability analysis method is used to analyze the boundary layer and get the transition point. In this study, the influences of different actuation intensities and positions are investigated, and results show that if the actuation intensity is stronger and the actuation position is closer to the base transition point, more drag reduction can be obtained. However, the efficiency of plasma transition delay is really low. For example, when the actuation voltage is 16 kV, the actuation frequency is 1 kHz, and the main Mach number is 0.1, the saved power due to drag reduction is about 5.09 W, but the power consumed is about 32.61 W, and the efficiency is just 15.6%.

Hollow nanoparticles are of great interest in energy storage and environmental remediation due to their improved mass transfer ability and unique void space for confined pollutants. Herein, fabrication of highly efficient and recyclable hollow porous γ-Fe2O3 nanotubes is reported by direct thermolysis of MIL-88A (Fe) precursors. Metal-organic frameworks (MOFs) that served as the precursors of the hollow γ-Fe2O3 nanotubes were first synthesized by a facile hydrothermal method followed by a one-step annealing process. As a proof-of-concept application, the as-synthesized hollow porous γ-Fe2O3 nanotubes were used in the lithium-ion battery and dye adsorption, respectively. Taking advantage of the hollow porous structure, γ-Fe2O3 nanotubes exhibited excellent lithium-ion batteries performance (1559 mAh g−1 at 100 mA g−1) and corresponding long cycle life (1093 mAh g−1 after 240 cycles at 100 mA g−1). At the same time, maximum methyl orange (MO) uptake capacity for the as-prepared hollow γ-Fe2O3 was calculated to be as high as 63.17 mg g−1. Moreover, this adsorbent also showed good reusability through the application of an external magnetic field, further highlighting the porous structure superiority of these hollow nanotubes. This proposed strategy could be extended to synthesize various hollow metal oxide porous nanoparticles with controllable structure, enhanced energy storage capacity and better environmental remediation performances.

We report the first planar hexacoordinate gallium (phGa) center in the global minimum of the GaBe6Au6+ cluster which has a star-like D6h geometry with 1A1g electronic state, possessing a central gallium atom encompassed by a Be6 hexagon and each Be–Be edge is further capped by an Au atom. The electronic delocalization resulting in double aromaticity (both σ and π) provides electronic stability in the planar form of the GaBe6Au6+ cluster. The high kinetic stability of the title cluster is also understood by Born–Oppenheimer molecular dynamics simulations. The energy decomposition analysis in combination with the ‘natural orbitals for chemical valence’ theory reveals that the bonding in the GaBe6Au6+ cluster is best expressed as the doublet Ga atom with 4s24p⊥1 electronic configuration forming an electron-sharing π bond with the doublet Be6Au6+ moiety followed by Ga(s)→[Be6Au6+] σ-backdonation and two sets of Ga(p‖)←[Be6Au6+] σ-donations., A star-like texture containing a planar hexacoordinate gallium center is reported in the lowest energy isomer of the GaBe6Au6+ cluster. High thermodynamic and kinetic stability of the title cluster makes it suitable candidate for experimental realization.

The electronic and structural prerequisites for a multi-layered molecular rotor have been demonstrated herein in terms of nine 18-valence-electron metallocene sandwich complexes. First, the lack of strong covalent bonds between layers is a key issue to obtain a barrier-free rotation of one layer relative to other layers, where the considerable energetic but unidirectional (such as electrostatic interactions) interactions are needed between layers to keep the structural integrity against fragment separation and structural distortion in a rotation process. Second, one or more layers should possess continuous and delocalized π electron clouds to provide a driving force for the barrier-free rotation. More importantly, besides a negligible rotation barrier, the reasonable rotational period associated with the ultra-soft rotation mode is a critical point for the observability of dynamical behavior in multi-layered molecular rotors.

Highly efficient and thermally stable broadband near-infrared (NIR) phosphors are urgently required for phosphor-converted light-emitting diodes (pc-LEDs), which are compact, low cost and promising for applications such as food analysis and agricultural science. Herein, a NIR phosphor, GdAl3(BO3)4:Cr3+ (GAB:Cr3+), with high emission efficiency and excellent thermal stability is presented. Under blue light excitation, GAB:Cr3+ shows a broad emission band covering 650–1000 nm with a full width at half maximum of ∼140 nm. Particularly, the 1.0 at% Cr3+ doped sample exhibits a photoluminescence (PL) quantum yield as high as 91%, and no decline of the PL intensity is observed even when the temperature is raised from 298 to 423 K. By combining the GAB:Cr3+ phosphor with a commercial blue LED chip, a high-performance NIR pc-LED is fabricated with a NIR radiant flux of 81 mW under a drive current of 350 mA. Furthermore, an aging test was performed on this device at 85 °C and 85% humidity for 480 h, and the radiant flux retained up to 95% of its initial value, which is comparable to the commercial phosphors. These results suggest that GAB:Cr3+ is a promising candidate for broadband pc-LEDs in NIR spectroscopy applications.

Transition metal-based catalysts usually suffer from poor coke resistance during the dehydrogenation processes of hydrocarbon compounds in gas–solid heterogeneous systems, including methanol dehydr...

The return sample of the reciprocating compressor revealed that the failure of a few suction valves was detected in a transitory time. To deal with this unconventional failure problem, microscopy and failure analysis were conducted and compared with the conventional failure type. The failure assumptions were proposed due to this, and a mathematical model using Fluid-Structure-Interaction (FSI) method was developed to investigate the stress performance and the failure mechanism. Moreover, an accelerated experimental facility was set up to validate the theoretical and numerical results. Results showed that the shear stress was the main reason for the short-time failure, and the head part of the suction valve experienced stress concentration. The failure started from the center of the suction valve's head part and resulted in its fracture at last. The thicker suction valve had the less stress concentration, and the valve head with a less hydraulic diameter had a minor failure possibility during the compression process. It provides reference for the unconventional failure problem during the practical engineering.

The blanket boron implant (BBI) in the sigma-shaped trench before the embedded SiGe (eSiGe) source/drain (S/D) formation for 28-nm PMOSFET is proposed in this letter. It is demonstrated that the BBI can significantly reduce the S/D junction capacitance with little influence on On/Off characteristic. In addition, the 1/ ${f}$ noise is also effectively lowered.

A modified tempering treatment has been designed in order to avoid the direct transformation of retained austenite (Ar) during tempering of a low-alloy Cr–Mo–V steel. Instead of the direct transformation of Ar into ferrite and M23C6 carbides during conventional tempering at 700 °C, transformation into aggregate of ferrite and cementite has been forced by a pre-tempering at 455 °C before conventional tempering. Experiments have been performed on specimens quenched with cooling rates 1.5, 3 and 12 °C/s, providing different types of Ar within the as-quenched microstructures. The results show that the tempering modification does not improve the Charpy impact toughness at the highest quenching rate of 12 °C/s, where the specimens cannot incur cleavage cracking induced from fine and discontinuous M23C6 carbides along lath interfaces. For the lowest quenching rate 1.5 °C/s, the Charpy impact toughness can be improved, and the failure is dominated by carbide aggregates, which originate from the decomposed products of blocky Ar. This is because the tempering modification effectively suppresses the formation of coarse M23C6 carbides at interfaces between the carbide aggregate and bainitic matrix, thereby resulting in a relatively homogeneous distribution of M23C6 carbides inside carbide aggregates. Therefore, the tempering modification is recommended for large-scale forgings, in which relatively high quenching rates are difficult to achieve.

Silver clusters with atomic precision have garnered immense attention owing to their aesthetic structures and fascinating properties. Assembly of silver clusters involves organizing positively charged silver ions into an intricate entity in an ordered fashion. To this end, the established effective route to assemble well-ordered silver clusters uses facile template anions as structure-directing agents. The past decades have witnessed a single anion template strategy widely used to construct silver clusters. In order to overcome the nuclearity limitation from the single anion template, multiple anionic templates have been recently introduced into the controllable preparation of high-nuclearity silver clusters. In this highlight, we will summarize the recent advances in homo- and hetero-anion templated silver clusters, in which their synthetic methods, crystal structures and anionic template directing effects as well as properties will be discussed.

The global minimum of XMg4Y− (X = Si, Ge; Y = In, Tl) and SiMg3In2 contains a planar pentacoordinate atom of group 14 other than carbon. Its design is based on the “localization” approach, replacing one or two peripheral atoms in XMg52− by more electronegative ones. This change diminishes the repulsion and leads to stronger covalent X–Y bonds, stabilizing the planar pentacoordinate atom species.

For over 100 years, known bent CC compounds have been limited to those with organic (I) and all-carbon (II) scaffoldings. Here, we computationally report a novel type (III) of bent CC compound, i.e., C2Al4F6-01, which is the energetically global minimum isomer and bears an inorganic–metallic scaffolding and unexpected click reactivity.

We present a global planar pentacoordinate carbon (ppC) featuring a hitherto unreported σ–σ diradical characteristic. Using the multi-reference approach combined with the CCSD(T)/aug-cc-pVTZ method, the ppC C3Li3− was found to be an intriguing triplet ground state, in which the unpaired density is mostly located at three Li ligands. Chemical bonding analysis reveals that the 2pz π electrons of C3Li3− are fully located at the C3 ring formed by C–C multiple bonds, in contrast to the perfect 2pz π-delocalization found in the well-known ppCs.

A series of ZnO nanoflakes modified with rare earth ions of Er and Sm were prepared by a simple chemical solution deposition approach. It was found that the doping content of rare-earth ions was dominant for the defects in the nanoflakes and the ability of photocatalytic degradation for rhodamine B (RhB). The ZnO:(Er, Sm) nanoflakes exhibited a superior photocatalytic activity compared to undoped ZnO mainly due to the longer lifetime of photogenerated electrons-hole pairs in the process of photocatalytic reaction, and Zn0.98Sm0.01Er0.01O nanoflakes could degrade 96.5% RhB within 60 min under UV light irradiation. PL results provided a strong evidence for the existence of VO defect, which was also found to be responsive for the enhanced photocatalytic activity of ZnO:(Er, Sm) nanoflakes. And the peaks at 515 nm and 550 nm could be attributed to the transitions of $$^{2} H_{11/2} \to^{4} I_{15/2}$$ and $$^{4} S_{3/2} \to^{4} I_{15/2}$$ from Er3+ ions, indicating the realization of green luminescence.

We demonstrate a laser frequency stabilization method with large tuning range to stabilize a UV laser by installing piezoelectric ceramic actuators into a Fabry–Pérot cavity with an ultra-low expansion spacer. To suppress piezoelectric drift, a two-layer symmetrical structure is adopted for the piezoelectric actuator, and a 14.7 GHz tuning range is achieved. The short-term drift of the piezoelectric ceramics caused by temperature and creep is eliminated, and the long-term drift is 0.268 MHz/h when the Fabry–Pérot cavity is sealed in a chamber without a vacuum environment. The long-term frequency drift is mainly caused by stress release and is eliminated by compensating the cavity voltage with an open loop. Without the need for an external reference or a vacuum environment, the laser frequency stabilization system is greatly simplified, and it can be extended to wavelengths ranging from ultraviolet to infrared. Owing to its simplicity, stability, and large tuning range, it is applicable in cold atom and trapped ion experiments.

Optical controls provided by lasers are the most important and essential techniques in trapped ion and cold atom systems. It is crucial to increase the optical accessibility of the setup to enhance these optical capabilities. Here, we present the design and construction of a new segmented-blade ion trap integrated with a compact glass vacuum cell, in place of the conventional bulky metal vacuum chamber. The distance between the ion and four outside surfaces of the glass cell is 15 mm, which enables us to install four high-numerical-aperture (NA) lenses (with two NA ⩽ 0.32 lenses and two NA ⩽ 0.66 lenses) in two orthogonal transverse directions, while leaving enough space for laser beams in the oblique and longitudinal directions. The high optical accessibility in multiple directions allows the application of small laser spots for addressable Raman operations, programmable optical tweezer arrays, and efficient fluorescence collection simultaneously. We have successfully loaded and cooled a string of 174Yb+ and 171Yb+ ions in the trap, which verifies the trapping stability. This compact high-optical-access trap setup not only can be used as an extendable module for quantum information processing but also facilitates experimental studies on quantum chemistry in a cold hybrid ion-atom system.

The activation of C–H bonds is a central challenge in organic chemistry and usually a key step for the retro-synthesis of functional natural products due to the high chemical stability of C–H bonds. Electrochemical methods are a powerful alternative for C–H activation, but this approach usually requires high overpotential and homogeneous mediators. Here, we design electron-deficient W2C nanocrystal-based electrodes to boost the heterogeneous activation of C–H bonds under mild conditions via an additive-free, purely heterogeneous electrocatalytic strategy. The electron density of W2C nanocrystals is tuned by constructing Schottky heterojunctions with nitrogen-doped carbon support to facilitate the preadsorption and activation of benzylic C–H bonds of ethylbenzene on the W2C surface, enabling a high turnover frequency (18.8 h−1) at a comparably low work potential (2 V versus SCE). The pronounced electron deficiency of the W2C nanocatalysts substantially facilitates the direct deprotonation process to ensure electrode durability without self-oxidation. The efficient oxidation process also boosts the balancing hydrogen production from as-formed protons on the cathode by a factor of 10 compared to an inert reference electrode. The whole process meets the requirements of atomic economy and electric energy utilization in terms of sustainable chemical synthesis. Designing electrode materials for mild and additive-free activation of C–H bonds is of great challenge. The authors report the application of electron-deficient W2C nanocrystal electrodes to boost the dissociation of C-H bonds toward the efficient alkoxylation and hydrogen evolution reactions.

Among the list of planar tetracoordinate atoms, fluorine is missing. So far, there are no theoretical or experimental reports suggesting their existence. Herein, we introduce the first six combinations (FIn4+, FTl4+, FGaIn3+, FIn2Tl2+, FIn3Tl+, and FInTl3+) whose global minima contain a planar tetracoordinate fluorine. The bonding analyses indicate that the interactions between the fluorine and the peripheral atoms are significantly electrostatic, which is also reflected in the electronic delocalization. As opposed to other planar tetracoordinate systems with carbon, nitrogen, or oxygen atoms, the fluorine in the ptFs does not act as a σ-acceptor, restraining any back-donation. On the other hand, σ-electrons show a diatropic response, which would characterize these clusters as σ-aromatic., The first global minima with a planar tetracoordinate fluorine atom are introduced. Their stabilization depends mainly on subtle ionic interactions and an adequate cavity.

Understanding the self-assembly mechanisms of amphiphilic molecules in solutions and regulating their phase behaviors are of primary significance for their applications. To challenge the reported direct phase transitions from nonlamellar to ordered lamellar phases, the self-assembly and phase behavior of the 1-hexadecyl-3-methylimidazolium chloride aqueous dispersions were studied using a strategy of isothermal incubation after the temperature jump. A disordered lamellar phase (identified as the lamellar liquid-crystal (Lα) phase), serving as an intermediate, was found to bridge the transition from a spherical micellar (M) phase to a lamellar-gel (Lβ) phase. Meanwhile, the nonsynchronicity in the tail and headgroup regions of the ionic liquid surfactant during the transition process was also unveiled, with the former being prior to the latter. The in-depth understanding of the self-assembly mechanisms may help push forward the related applications in the future.

Mechanical stress induced by bonding low-polarization GaAsP/AlGaAs quantum-well superluminescent diodes with p-side-up and p-side-down bonding methods has been observed using measurements of the degree of polarization. Due to the closer distance from the heat-sink to active region and the thermal expansion coefficient mismatch between the oxygen-free copper heat-sink and GaAs-based chip, p-side-down bonding configuration were observed to have a larger stress than p-side-up one. The high temperature accelerated aging test of SLDs with both bonding methods was carried out and discussed. Results suggested that such a bonding stress in superluminescent diode might degrade device's performance, i.e. reducing the threshold level of catastrophic optical damage and improving the failure rate on accelerated aging test.

Amorphous ribbons from alloy Fe60Co19Zr9B12 are studied by differential thermal analysis and x-ray diffractometry after spinning the melt and one-stage and two-stage annealing. The magnetic properties (the saturation magnetization and the coercivity) are determined and the DTA curves are plotted. It is shown that the two-stage annealing affects positively the saturation magnetization and the coercivity.

The electron deficiency and strong bonding capacity of boron have created numerous species with unusual structural and electronic properties in the form of pure and hetero-atom doped boron clusters. Here we identified D9d-symmetry Na2B18 and Na2B18− tubular boron clusters as global minima, whose stability is significantly enhanced by two doped sodium atoms. The doped Na atoms trigger strong charge transfer from Na to the boron motifs, resulting in salt complexes (Na22+B182− and Na22+B183−). In particular, the optimal electrostatic interactions arising from the doping effect play a crucial role in stabilizing the tubular structure against the planar and quasi-planar preferences of the negatively charged boron clusters.

Substantial effort has been devoted to synthesizing plasmonic metal/semiconductor heteronanostructures with controlled morphology owing to their excellent performance ranging from photocatalysis to optical information processing. However, growing semiconductor heterojunctions with both counterparts in direct contact with the plasmonic metal nanostructures remains challenging. Herein, we report a three-step method to grow CdS–Cu2−xS lateral heteroshells on Au nanoparticles with all components directly connected with each other. Ag2S semi shells are initially grown on the Au nanoparticles as an interim layer, Cu2−xS semi shells are then grown on the uncovered surface of the Au nanoparticles, and CdS is generated by replacing Ag2S and the Au core complex with CdS–Cu2−xS lateral heteroshells Au/CdS–Cu2−xS is finally obtained. These complexes integrate the plasmon resonances of Au in the visible region and that of Cu2−xS in the near-infrared region, and therefore show improved photocatalytic activity and high photothermal efficiency. This study offers a synthetic approach to grow metal sulfides on Au nanostructures which have diverse applications in photocatalysis and photothermal therapy.

Covalent organic frameworks (COFs) have shown great potential for use in ion sensing; however, applications of existing COFs are limited to sensing either cations or anions. In this study, a three-dimensional COF, COF-TT, is constructed by reacting the bis(tetraoxacalix[2]arene[2]triazine) core with tetra(p-aminophenyl)methane to provide a luminescent sensor. COF-TT exhibits ultrahigh thermal stability and exceptional chemical stability in aqueous solutions over a broad pH range from 2 to 14, which signifies immense practical potential for sensing applications. Excellent selectivity and high sensitivity of COF-TT toward Fe3+ cations and CrO42−, Cr2O72−, and MnO4− anions are evident via luminescence quenching. COF-TT also exhibits excellent recyclability in terms of washing and re-exposure cycles. Both experimental data and theoretical calculations are employed to unveil the mechanisms of the quenching effect and sensing properties of COF-TT.

Strong couplings between molecular excitons and metal plasmons bring advantages to effectively manipulate the optical properties of hybrid systems, including both absorption and fluorescence. In contrast to absorption behaviours, which have been quite well understood and can be categorized into different regimes such as Fano dip and Rabi splitting, the characteristics of fluorescence in strongly coupled hybrids remain largely unexplored. Quenching instead of the enhancement of fluorescence is usually observed in the corresponding experiments, and a theoretical model to deal with this phenomenon is still lacking. Herein, we demonstrate a largely enhanced fluorescence in a hybrid system with Cy5 dye molecules strongly coupled to Ag nanoparticle films, signified by the huge Rabi splitting absorption spectra. The plexciton Rabi splitting of the hybrids can be tuned from 320 meV to as large as 750 meV by adjusting both plasmon strength and molecular concentration. Moreover, when the excitation and emission wavelengths are respectively tuned to be resonant with the two Rabi peaks, the hybrid acting as a plexcitonic dual resonant antenna exhibits an enhanced fluorescence 44 times larger than that of the free dye molecule. We also develop a theoretical model to simultaneously study the characteristics of both the absorption and emission spectra, including the peak shifting and strength. These findings offer a new strategy to design and fabricate plexcitonic devices with tunable optical responses and efficient fluorescence.

Zn–Al layered double hydroxides (Zn–Al LDHs) with various reaction times were synthesized by a hydrothermal method at constant pH, and they were tested for the removal of RhB with or without post-calcination treatment. The effect of reaction time and calcination treatment on the structures, morphologies, chemical compositions and photocatalytic properties of Zn–Al LDHs was analyzed by XRD, TG/DSC, SEM, XPS, FTIR, Raman, PL and UV-vis DRS in detail. The optimized Zn–Al LDHs with a book page morphology had good crystal quality and the sample morphology changed to irregular flakelets with increasing calcination temperature. The RhB photodegradation results showed that the photocatalytic activity of Zn–Al LDHs was enhanced with increasing reaction time due to the improved crystal quality and the better separation of photogenerated electron–hole pairs. It was found that the calcination temperature was also an important factor for the c-Zn–Al-LDH samples, and the c-Zn–Al-LDH-24-300 sample exhibited the best photocatalytic activity due to the highest efficiency of photogenerated electron–hole separation, especially the formation of a new phase. A pseudo first order rate and recycling experiments were also used to analyze the photocatalytic activity.

We synthesize Au@WS2 hybrid nanobelts and investigate their third-order nonlinear responses mediated by a strong anti-Stokes effect. By using the femtosecond Z-scan technique and tuning the excitation photon energy (Eexc), we find the sign reversals of both nonlinear absorption coefficient β and nonlinear refractive index γ to be around 1.60 eV, which is prominently higher than the bandgap (1.35 eV) of WS2 bulk owing to the strong anti-Stokes processes around the bandgap of the indirect semiconductors. The saturable absorption and self-defocusing of the WS2 nanobelts are significantly enhanced by the plasmon resonance of the Au nanoparticles when Eexc > 1.60 eV. But the excited state absorption assisted by the anti-Stokes processes and the self-focusing observed at Eexc < 1.60 eV are suppressed by the surface plasmon. Furthermore, by using population rate equations, we theoretically analyze the sign reversals of both β and γ and reveal the physical mechanism of the unique nonlinear responses of the hybrids with the plasmon resonance and anti-Stokes effect. These observations enrich the understanding of the nonlinear processes and interactions between the plasmon and exciton and are helpful for developing nonlinear optical nanodevices.

Herein we introduce a strategy employing lithium atoms as a scaffold to stabilize an embryo for boron tubes. The systematical exploration of the potential energy surface via evolutionary algorithms allowed us to find that Li2B24 adopts a tubular structure formed by three stacked rings of eight borons each with two lithium atoms capping the tube. The lithium atoms are essential for stabilization because of the strong electrostatic interaction between the Li cations and the boron framework, and concomitantly, they compensate for the energy cost of distorting a quasi-planar or double ring B24 cluster.

Herein, a zero-dimensional (0D) hybrid organic–inorganic metal halide (OIMH) [BPy]6[Pb3Br12] (BPB, BPy = N-butylpyridinium) as a room-temperature phosphorescent (RTP) material is synthesized. Through molecular sensitization, its RTP quantum efficiency can be increased by a maximum of 14-fold. A white-light-emitting device is obtained via a solvent-free and eco-friendly melting method.

The putative global minimum of clusters with formula B10M2 (M = Rh, Ir) corresponds to icosahedral structures formed by two alternately stacked B5 rings with the metals located at the top and bottom vertices. These structures are the closest approximation of molecular clusters to the elusive icosahedral boron. A detailed analysis of the chemical bonding revealed that the covalent character between the transition metal and the boron framework as well as the strong delocalization throughout the structure enhances the stabilization of the icosahedral form.

Based on traditional twin-roll casting process, Invar/Cu clad strips were successfully fabricated by using solid Invar alloy strip and molten Cu under conditions of high temperature, high pressure and plastic deformation. A series of tests including tensile test, bending test, T-type peeling test and scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) measurements were carried out to analyze the mechanical properties of Invar/Cu clad strips and the micro-morphology of tensile fracture surfaces and bonding interfaces. The results indicate that no delamination phenomenon occurs during the compatible deformation of Invar/Cu in bending test and only one stress platform exists in the tensile stress−strain curve when the bonding strength is large. On the contrary, different mechanical properties of Invar and Cu lead to delamination phenomenon during the uniaxial tensile test, which determines that two stress platforms occur on the stress−strain curve of Invar/Cu clad strips when two elements experience necking. The average peeling strength can be increased from 13.85 to 42.31 N/mm after heat treatment at 800 °C for 1 h, and the observation of the Cu side at peeling interface shows that more Fe is adhered on the Cu side after the heat treatment. All above illustrate that heat treatment can improve the strength of the bonding interface of Invar/Cu clad strips.

In order to describe and predict the kinetic process of discontinuous dynamic recrystallization (DDRX) during hot working for metals with low to medium stacking fault energies quantitatively, a new physically-based model was proposed by considering the characteristics of grain size distribution, capillary effect of initial grain boundaries (GBs) and continuous consumption of GBs. Using Incoloy 028 alloy as a model system, experiments aiming to provide kinetic data (e.g., the size and volume fraction of recrystallized grain) and the associated microstructure were performed. Good agreement is obtained between model predictions and experimental results, regarding flow stress, recrystallized fraction and grain size evolution. On this basis, a thermo-kinetic relationship upon the growth of recrystallized grain was elucidated, i.e., with increasing thermodynamic driving force, the activation energy barrier decreases.

Au@Cu2O core-shell nanorods with tunable thickness of Cu2O shell were synthesized and their linear and nonlinear optical responses were investigated. Two transverse plasmon resonance peaks were observed when the Au nanorods were coated with Cu2O shells, which were adjusted by the Cu2O shell thickness. The nonlinear absorption of the Au@Cu2O nanorods is enhanced by 5 times at the longitudinal plasmon resonance wavelength compared with that of bare Au nanorods. More intriguingly, largely enhanced nonlinear refraction and suppressed nonlinear absorption at the transverse plasmon resonance wavelength were observed in the Au@Cu2O nanorods. Our findings indicate the existence of strong local field enhancement at the interface between the Au core and the Cu2O shell, which would provide a promising strategy in designing plasmonic nonlinear nanodevices with good nonlinear figures of merit.

We have predicted four squaraine (SQ) structures with different heterocyclic anchoring groups (HAGs), including hydantoin moiety (HY), rhodanine (RD), 2-(1,1-dicyanomethylene) (DCRD) and barbituric acid (BA), to simultaneously enhance the lower open-circuit photovoltage (Voc) and adsorption stability of the gold-standard SQ dye with widely used carboxylic acid anchoring group (CA) without sacrificing its extremely large short-circuit current (Jsc). For the first time, these HAGs are put together to discuss their impacts on the relative adsorption stability and the intrinsic reasons affecting the Voc, including adsorption modes, conduction band energy shift (ΔECB), electron injection, charge recombination, and the dye aggregation effects. Especially, charge decomposition analysis has been performed to explain the origin of different extent of ΔECB, and the reduced density gradient analysis offers a pictorial representation of the weak interactions between the two monomers. The results show that the adsorption stability order is BA ≈ HY > RD ≈ CA > DCRD. And the Voc order is BA > HY > RD > CA > DCRD. In addition, we find these SQ dyes show comparable maximum photocurrent density (about 22 mA/cm2). Thus, SQ dyes with BA, HY, and RD are promising candidates for the experimental synthesis of high-performance dye sensitized solar cells.

The exploitation of metal-free organic polymers as electrodes for water splitting reactions is limited by their presumably low activity and poor stability, especially for the oxygen evolution reaction (OER) under more critical conditions. Now, the thickness of a cheap and robust polymer, poly(p-phenylene pyromellitimide) (PPPI) was rationally engineered by an in situ polymerization method to make the metal-free polymer available for the first time as flexible, tailorable, efficient, and ultra-stable electrodes for water oxidation over a wide pH range. The PPPI electrode with an optimized thickness of about 200 nm provided a current density of 32.8 mA cm-2 at an overpotential of 510 mV in 0.1 mol L-1 KOH, which is even higher than that (31.5 mA cm-2 ) of commercial IrO2 OER catalyst. The PPPI electrodes are scalable and stable, maintaining 92 % of its activity after a 48-h chronoamperometric stability test.

Different LiNi0.8Co0.15Al0.05O2 cathode materials were washed by ethanol solvent. Inductively coupled plasma atomic emission spectroscopy (ICP-AES), Fourier transformed infrared (FTIR) spectrum, X-ray diffraction (XRD), scanning electron microscopy (SEM), charge–discharge test and electrochemical impedance spectroscopy (EIS) were used to evaluate the elemental contents, structures, morphologies and electrochemical properties of samples. The results show that ethanol washing can remove effectively the synthetic residues LiOH/Li2O on the freshly-prepared LiNi0.8Co0.15Al0.05O2 and make the sample much more resistant to H2O and CO2, without destroying its bulk structure, surface morphology and electrochemical performances. Moreover, the discharge specific capacity and cycle performance of LiNi0.8Co0.15Al0.05O2 after storage in air with a relative humidity of 80% for three months are improved by immediate ethanol washing.

Fe3O4@MIL-100 (Fe)/PEI are used for the first time as an adsorbent material for the extraction of pesticide residues (epoxiconazole, flusilazole, tebuconazole, and triadimefon) from food matrices. The adsorbent proposed (Fe3O4@MIL-100(Fe)/PEI) was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), thermogravimetric (TG) analysis, and vibrating sample magnetometer (VSM) techniques to evaluate the properties of the sorbent. Then, the Fe3O4@MIL-100 (Fe)/PEI was employed for the quantification of the four triazole fungicides in fruits and vegetables (apple, orange, tomato, cabbage, and cucumber) using HPLC-UV for separation and detection. During the extraction process, the main parameters such as amount of adsorbent, extraction time, pH value, ionic strength, eluting solvent, and eluting volume were optimized. Under the optimum conditions, good linearity of this method was observed for all analytes, with correlation coefficients (R2) ≥ 0.9908. The limits of detection (LODs) ranged from 0.021–3.04 μg kg−1. The extraction recoveries of the four triazole fungicides varied from 73.9 to 109.4% with relative standard deviations (RSD) in the range 0.5 to 6.2%. Compared with other MOFs, the modification of Fe3O4@MIL-100 (Fe) with PEI shows high efficient adsorption due to the combined benefits of MIL-100 (Fe) and PEI. The material is easily synthesized, has good stability, and is of low cost.

Transition-metal-centered monocyclic boron wheels are important candidates in the family of planar hypercoordinate species that show intriguing structure, stability and bonding situation. Through the detailed potential energy surface explorations of MB9− (M = Fe, Ru, Os) clusters, we introduce herein OsB9− to be a new member in the transition-metal-centered borometallic molecular wheel gallery. Previously, FeB9− and RuB9− clusters were detected by photoelectron spectroscopy and the structures were reported to have singlet D9h symmetry. Our present results show that the global minimum for FeB9− has a molecular wheel-like structure in triplet spin state with Cs symmetry, whereas its heavier homologues are singlet molecular wheels with D9h symmetry. Chemical bonding analyses show that RuB9− and OsB9− display a similar type of electronic structure, where the dual σ + π aromaticity, originated from three delocalized σ bonds and three delocalized π bonds, accounts for highly stable borometallic molecular wheels.

The effect of Ti and B microalloying on the hardenability, prior austenite grain size (PAGS), mechanical properties, and sulfide stress cracking (SSC) of C110 grade steel was studied by Jominy testing, static tensile testing, an optical microscope (OM), scanning electron microscopy (SEM) and double cantilever beam (DCB) testing. The results show that the addition of 0.015% Ti and 0.002% B into a medium-carbon Fe-Cr-Mo-Nb-V steel increased the hardenability and refined the PAGS and quenched martensite packets, and the size of carbides was reduced. It is believed that these behaviors are responsible for the improvement in the threshold stress intensity factor KISSC.

Hepatocellular carcinoma (HCC) is one of the diseases with high mortality worldwide, so its early diagnosis and treatment have attracted much attention. Due to the advantages of the high sensitivity of surface-enhanced Raman scattering (SERS) detection, SERS has excellent application value in the diagnosis of HCC. In this paper, silver nanoparticles (AgNPs) are modified by magnetron sputtering on the surface of polystyrene (PS) templates with spheres of two different diameters. The array of units surrounded by particles is successfully prepared and the SERS performance is characterized. The effect of the gap between AgNPs on plasmon coupling and hot spot distribution is discussed. Finite-difference time domain (FDTD) simulation is used to verify the electric fields and hot spot distribution of the array. The differences in the concentrations of HCC markers are analyzed by using the change of SERS signal intensity of the array. The whole process proves that the preparation of structures with a strong local electric field to provide highly sensitive SERS signals is a key link in the detection of HCC markers, which is conducive to the diagnosis of HCC and has potential application value in clinical diagnosis.

In order to study the transient characteristics of a nuclear reactor coolant pump in coast-down process under power failure condition, a transient test device for the nuclear reactor coolant pump is set up. This study investigates the effects of the rotor of the nuclear reactor coolant pump and the circuit characteristics on the nuclear reactor coolant pump during the coast-down process by changing the rotary inertia of the flywheel and the resistance of the pipe system. The results show that the greater the moment of inertia is, the more slowly rotational speed, flow, and lift get down in the same coast-down period. The change in the pipe resistance has little effect on the rate of decline in the coast-down process, but it has a great influence on the descent speed of the flow rate and lift. When the pipe resistance is small, the corresponding flow rate decreases faster, but it is slower for the corresponding lift. The results are of great significance in controlling the stability and reliability of the nuclear reactor coolant pump in the coast-down process.

A stepped planar microstrip structure is proposed and demonstrated as a candidate of the ultra-wideband (UWB) antenna in the paper. In the structure, two L-shaped slots are introduced into the rectangular microstrip patch to broaden the current path at both edges of the radiating patch. The impedance bandwidth of the antenna can be extended by using the stepped impedance resonator (SIR) structure at one end of the radiation patch and connecting with the feed line. The symmetrical two I-shaped slots are loaded on the SIR microstrip to improve in-band performance and further widen the operating band. The proposed new structure can have an improvement in the in-band characteristics while extending the operating bandwidth. A broadband impedance bandwidth of 2.39 GHz to 13.78 GHz at S11 &lt, &minus, 10 dB is demonstrated based on the proposed novel structure. The reflection coefficient and radiation characteristics are characterized in the paper. The tiny antenna, with the benefit of small area 36 mm &times, 23 mm, shows potential applications in ultra-wideband communication systems, wireless energy harvesting systems, and other wireless systems.

Gas sensors have a wide variety of applications. Among various existing gas sensing technologies, optical gas sensors have outstanding advantages. The development of the Internet of Things and consumer electronics has put stringent requirements on miniaturized gas sensing technology. Here, we demonstrate a chip-scale silicon substrate-integrated hollow waveguide (Si-iHWG) to serve as an optical channel and gas cell in an optical gas sensor. It is fabricated through silicon wafer etching and wafer bonding. The Si-iHWG chip is further assembled with an off-chip light source and detector to build a fully functional compact nondispersive infrared (NDIR) CO 2 sensor. The chip size is 10 mm × 9 mm , and the dimension of the sensor excluding the microcontroller board is 50 mm × 25 mm × 16 mm . This chip solution with compactness, versatility, robustness, and low cost provides a cost-effective platform for miniaturized optical sensing applications ranging from air quality monitoring to consumer electronics.