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Formic acid intercalated Mg-Al layered double hydroxide (Mg-Al Fo-LDH) was prepared by calcination reduction intercalation assembly technology. The structure of the deicing additive was characterized by fourier transform infrared (FTIR) and X-ray diffraction (XRD). The freezing point of aqueous solution with different quality of deicing additive and the surface freezing point and adhesion of asphalt mixture were tested. The results show that formic acid ion has been intercalated into the interlayer of Mg-Al layered double hydroxide by FTIR and XRD patterns. The freezing point of 5wt% Mg-Al Fo-LDH aqueous solution reaches -9.32 °C, while the surface freezing point of the asphalt mixture mixed with 5wt% Mg-Al Fo-LDH is -6.5°C. At -8 °C, the adhesion force of the surface ice layer is 78.4N, and after the asphalt mixture is soaked in water, the surface freezing point and adhesion force of the ice layer do not change.

Luminescent cuprous complexes are important coordination compounds due to their relative abundance, low cost and ability to display excellent luminescence. The structures of two CuIP2S-type cuprous complexes, namely, iodido(thiourea-κS)bis(triphenylphosphane-κP)copper(I), [CuI(CH4N2S)(C18H15P)2] or [CuI(TU)(TPP)2] (I), and (2,3-dihydrobenzimidazole-2-thione-κS)iodidobis(triphenylphosphane-κP)copper(I), [CuI(C7H6N2S)(C18H15P)2] or [CuI(DHBIT)(TPP)2] (II), are described. In these two structures, the complex molecules of both are constructed by one copper(I) centre, one iodide ion, two TPP ligands and one thione ligand (TU for I and DHBIT for II). The copper(I) centres of I and II are both located in a distorted CuIP2S tetrahedron and are coordinated by two P atoms from two TPP ligands, one S atom from the thione ligand and the I atom. The UV–Vis absorption and photoluminescence properties of these CuIP2S-type cuprous complexes have been studied using crystalline powder samples. Detailed time-dependent density functional theory (TD-DFT) calculations and wavefunction analysis reveal that the pale-blue–green phosphorescence emission should originate from intra-ligand (TPP for I and DHBIT for II) charge transfer, with a small component of the metal-to-ligand charge transfer 3(IL+ML)CT excited state.

Studies on GaAsBi-based devices have been deeply carried out in recent years, strongly driven by their excellent performance. Despite the growing interest in GaAsBi, the systematic researches on its vibrational and thermodynamic properties are still lacking. Hence, in this work, the structural, vibrational and thermodynamic properties of GaBixAs1-x are studied systematically by performing ab initio calculations. Firstly, the calculation structure constants of GaBixAs1-x are in accordance with other available data in the literature. Next, the results of the vibrational frequencies indicate that the phonon frequencies of GaBixAs1-x undergo a sharp decline when the bismuth concentration x is elevated. Besides the reduction of the phonon densities of states at the specified wave vector, the optical branches of GaBixAs1-x narrow and the attenuation of longitudinal modes is greater than that of transverse modes with the enhancement of the Bi concentration x. Then, the splitting degree $$\left( {\delta \omega } \right)$$ suggests that the ionic strength for GaBixAs1-x is declined when increasing the Bi composition. Finally, the thermodynamic functions of GaBixAs1-x ranging from $$\Delta F$$ , $$\Delta E$$ , $$C_{v}$$ and $$S$$ are predicted. In addition, the calculation values of the Debye temperature for GaBixAs1-x also confirm the change trend of phonon frequencies of the system.

Tyrosinase (TYR) is an important polyphenolic oxidase enzyme and usually regards as a biomarker of melanoma cancer. Highly effective tracking TYR activity in vivo will help to study the mechanism of TYR in living organisms and forecasts related diseases. In this study, we present a novel TYR-activatable fluorescent probe (CHMC-DOPA) for tracking TYR activity in vitro and in vivo. CHMC-DOPA is constructed by incorporating dopamine (DOPA) moiety into a fluorescent chloro-hydroxyl-merocyanine (CHMC) scaffold. Upon exposure to TYR, the dopamine unit in CHMC-DOPA is oxidized to a dopaquinone derivative, and an intramolecular photo-induced electron transfer (PET) process between CHMC fluorophore and o-dopaquinone will take place, the fluorescence of CHMC-DOPA is quenched rapidly. Therefore, the evaluation of TYR activity is established in terms of the relationship between fluorescence quenching efficiency and TYR activity. In our experiments, CHMC-DOPA shows various advantages, such as fast response (8⬰min), low concentration of TYR activation (0.5 U/mL), good water-solubility, as well as the lowest detection limit (0.003 U/mL) compared with previously reported works. Furthermore, CHMC-DOPA also exhibits excellent cell membrane permeability and low cytotoxicity, which is successfully used to monitor endogenous TYR activity in living cancer cells and zebrafish models. CHMC-DOPA performs well, and we anticipate that this newly designed novel platform will provide an alternative for high effective monitoring TYR activity in biosystems.

As a natural abundant high-carbon resource, the use of coal to develop carbon nanomaterials is an important research topic. In recent years, a variety of carbon materials with different morphologies and nanotextures have been designed and constructed using coal and their derivatives as precursors, and their use in energy storage, catalysis, adsorption and absorption have been explored. State-of-the-art research on carbon nanomaterials derived from coals of different rank and their derivatives are summarized with specific attention to the synthesis strategies and structure control. The use of these coal-derived carbons for energy storage, such as secondary batteries and supercapacitors, is also discussed in terms of their structural features. The review aims to provide valuable insight into the present challenges and inspire new ideas for the development of advanced coal-derived carbon materials.

As the existing NEXRAD network nears the end of its life cycle, intense study and planning are underway to design a viable replacement system. Ideally, such a system would offer improved temporal resolution compared to NEXRAD, without a loss in data quality. In this study, scan speedup techniques—such as beam multiplexing (BMX) and radar imaging—are tested to assess their viability in obtaining high-quality rapid updates for a simulated long-range weather radar. The results of this study—which uses a Weather Research and Forecasting (WRF) Model–simulated supercell case—show that BMX generally improves data quality for a given scan time or can provide a speedup factor of 1.69–2.85 compared to NEXRAD while maintaining the same level of data quality. Additionally, radar imaging is shown to improve data quality and/or decrease scan time when selectively used; however, deleterious effects are observed when imaging is used in regions with sharp reflectivity gradients parallel to the beam spoiling direction. Consideration must be given to the subsequent loss of sensitivity and beam broadening. Finally, imaging is shown to have an effect on the radar-derived mesocyclone strength (ΔV) of a simulated supercell. Because BMX and radar imaging are most easily achieved with an all-digital phased array radar (PAR), these results make a strong argument for the use of all-digital PAR for high-resolution weather observations. It is believed that the results from this study can inform decisions about possible scanning strategies and design of a NEXRAD replacement system for high-resolution weather radar data.

In recent years, with the rapid development of satellite technology, remote sensing inversion has been used as an important part of environmental monitoring. Remote sensing inversion has been prepared for large-scale water environment monitoring in the watershed that is difficult for the traditional water environment monitoring methods. This paper will discuss some shortcomings of traditional remote sensing inversion methods, and proposes a remote sensing inversion method based on convolutional neural network, which realizes large-scale remote sensing smart and automatic inversion monitoring of the water environment. The results show that the method is practical and effective, and can achieve high recognition accuracy for water blooms.

Gold nanoclusters (AuNCs) have been recognized as an emerging category of inorganic–organic hybrid luminescent materials owing to their ultrasmall size, good biocompatibility, and especially the ag...

Rhododendron datiandingense is newly reported and endemic to China. The genome of R. datiandingense is 207,311 bp in length, including a large single-copy region of 190,689 bp and a small single-copy region of 2582 bp, a pair of inverted repeat regions (IRA) of 7020 bp each. The genome encodes 110 genes, comprising 77 protein-coding genes, four ribosomal RNA genes, and 29 transfer RNA genes. Repeat analysis revealed 62 simple sequence repeats (SSRs) in the genome. Phylogenetic analysis revealed that R. datiandingense is clearly separated from the other Rhododendron species and shown in the basal position.

Phased-array radar (PAR) technology offers the flexibility of sampling the storm and clear-air regions with different update times. As such, the radial velocity from clear-air regions, typically with a lower signal-to-noise ratio, can be measured more accurately. In this work, observing system simulation experiments are conducted to explore the potential value of assimilating clear-air radial velocity observations to improve numerical prediction of supercell thunderstorms. Synthetic PAR observations of a splitting supercell are assimilated at different life cycle stages using an ensemble Kalman filter. Results show that assimilating environmental clear-air radial velocity can reduce wind errors in the near-storm environment and within the precipitation region. Improvements in the forecast are seen at different stages, especially for the forecast after 30 min. After assimilating clear-air radial velocity observations, the probabilities of updraft helicity and precipitation within the corresponding swaths of the truth simulation increase up to 30%–40%. Additional diagnostics suggest that the more accurate track forecast, stronger vertical motion, and better-maintained supercell can be attributed to the better analysis and prediction of the mean environmental winds and linear and nonlinear dynamic forces. Consequently, assimilating clear-air radial velocity produces accurate storm structure (rotating updrafts), updraft size, and storm track, and improves the surface accumulated precipitation forecast. The performance of forecasts with a higher frequency of assimilating clear-air radial velocity does not show systematic improvement. These results highlight the potential of assimilating clear-air radial velocity observations to improve numerical weather prediction forecasts of supercell thunderstorms.

Domestic species provides a powerful model for examining genetic mechanisms in the evolution of yield traits. The domestic silkworm (Bombyx mori) is an important livestock species in sericulture. While the mechanisms controlling cocoon yield are largely unknown. Here, using B. mori and its wild relative B. mandarina as intercross parents, 100 BC1 individuals were sequenced by restriction site-associated DNA sequencing (RAD-Seq). The linkage map contained 9,632 markers was constructed. We performed high-resolution quantitative trait locus (QTL) mapping for four cocoon yield traits. A total of 11 QTLs were identified, including one yield-enhancing QTL from wild silkworm. By integrating population genomics and transcriptomic analysis with QTLs, some favourable genes were revealed, including 14 domestication-related genes and 71 differentially expressed genes (DEGs) in the fifth-instar larval silk gland transcriptome between B. mori and B. mandarina. The relationships between the expression of two important candidate genes (KWMTBOMO04917 and KWMTBOMO12906) and cocoon yield were supported by quantitative real-time PCR (qPCR). Our results provide some new insights into the molecular mechanisms of complex yield traits in silkworm. The combined method might be an efficient approach for identifying putative causal genes in domestic livestock and wild relatives.

Luminescent cuprous complexes are an important class of coordination compounds due to their relative abundance, low cost and ability to display excellent luminescence. The heteroleptic cuprous complex solvate rac-(acetonitrile-κN)(3-aminopyridine-κN)[2,2′-bis(diphenylphosphanyl)-1,1′-binaphthyl-κ2 P,P′]copper(I) hexafluoridophosphate dichloromethane monosolvate, [Cu(C5H6N2)(C2H3N)(C44H32P2)]PF6·CH2Cl2, conventionally abbreviated as [Cu(3-PyNH2)(CH3CN)(BINAP)]PF6·CH2Cl2, (I), where BINAP and 3-PyNH2 represent 2,2′-bis(diphenylphosphanyl)-1,1′-binaphthyl and 3-aminopyridine, respectively, is described. In this complex solvate, the asymmetric unit consists of a cocrystallized dichloromethane molecule, a hexafluoridophosphate anion and a complete racemic heteroleptic cuprous complex cation in which the cuprous centre, in a tetrahedral CuP2N2 coordination, is coordinated by two P atoms from the BINAP ligand, one N atom from the 3-PyNH2 ligand and another N atom from a coordinated acetonitrile molecule. The UV–Vis absorption and photoluminescence properties of this heteroleptic cuprous complex have been studied on polycrystalline powder samples, which had been verified by powder X-ray diffraction before recording the spectra. Time-dependent density functional theory (TD-DFT) calculations and a wavefunction analysis reveal that the orange–yellow phosphorescence emission should originate from intra-ligand (BINAP) charge transfer mixed with a little of the metal-to-ligand charge transfer 3(IL+ML)CT excited state.

3D-printing tough conductive hydrogels (TCHs) with complex structures is still a challenging task in related fields due to their inherent contrasting multinetworks, uncontrollable and slow polymerization of conductive components. Here we report an orthogonal photochemistry-assisted printing (OPAP) strategy to make 3D TCHs in one-pot via the combination of rational visible-light-chemistry design and reliable extrusion printing technique. This orthogonal chemistry is rapid, controllable, and simultaneously achieve the photopolymerization of EDOT and phenol-coupling reaction, leading to the construction of tough hydrogels in a short time (tgel ~30 s). As-prepared TCHs are tough, conductive, stretchable, and anti-freezing. This template-free 3D printing can process TCHs to arbitrary structures during the fabrication process. To further demonstrate the merits of this simple OPAP strategy and TCHs, 3D-printed TCHs hydrogel arrays and helical lines, as proofs-of-concept, are made to assemble high-performance pressure sensors and a temperature-responsive actuator. It is anticipated that this one-pot rapid, controllable OPAP strategy opens new horizons to tough hydrogels., 3D-printing tough conductive hydrogels (TCHs) with complex structures is still a challenging task due to their inherent contrasting multinetworks, uncontrollable and slow polymerization. Here the authors show an orthogonal photochemistry-assisted printing strategy to make 3D TCHs in one pot.

The anode oxygen evolution reaction (OER) is known to largely limit the efficiency of electrolyzers owing to its sluggish kinetics. While crystalline metal oxides are promising as OER catalysts, their amorphous phases also show high activities. Efforts to produce amorphous metal oxides have progressed slowly, and how an amorphous structure benefits the catalytic performances remains elusive. Now the first scalable synthesis of amorphous NiFeMo oxide (up to 515 g in one batch) is presented with homogeneous elemental distribution via a facile supersaturated co-precipitation method. In contrast to its crystalline counterpart, amorphous NiFeMo oxide undergoes a faster surface self-reconstruction process during OER, forming a metal oxy(hydroxide) active layer with rich oxygen vacancies, leading to superior OER activity (280 mV overpotential at 10 mA cm-2 in 0.1 m KOH). This opens up the potential of fast, facile, and scale-up production of amorphous metal oxides for high-performance OER catalysts.

The ultrasensitive bioassays are increasingly demanded for disease diagnosis and environmental monitoring. The combined unique natures of the components in nanocomposites have led to their wide applications in bioanalysis. In the current study, a simple strategy for preparing polyethyleneimine-functionalized reduced graphene oxide-hemin-bovine serum albumin (PEI-rGO-Hemin-BSA) nanocomposites as peroxidase mimetics was demonstrated. The developed nanocomposites of PEI-rGO-Hemin-BSA showed an excellent peroxidase-like activity. Importantly, through the glutaradelhyde crosslinking, PEI-rGO-Hemin-BSA could be further simply combined with various oxidases such as glucose oxidase, cholesterol oxidase, lactate oxidase and choline oxidase for the detection and quantitative measurement of multiple metabolites including glucose, cholesterol, l-lactate, and choline. The developed detection strategy, which is sensitive, convenient, low-costed, and in tiny sample consumption, could be expected wide applications in the disease diagnosis and management of metabolite disorders.

Density-functional-theory (DFT) calculations and molecular dynamics simulations were performed to resolve the fracture behavior in UO2 under tensile loading. By molecular dynamics simulation, potential dependence was identified on the existence of transient plastic deformation prior to intergranular fracture in polycrystalline UO2, so we further improved the Morelon interatomic potential based on GGA + U calculations to obtain reliable fracture behavior in UO2. Using the improved potential, the fracture behaviors in polycrystalline and single crystal UO2 under tensile loading were investigated. In polycrystalline UO2, brittle intergranular fracture was observed, and no phase transition was found. In single crystal, Fm 3 ¯ m - Pbcn and Fm 3 ¯ m - P 4 2 /mnm structural transitions were observed under tensile loading. The non-coherent interfaces between Pbcn and P42/mnm phases play a critical role in microcrack formation. Under tensile loading, only Fm 3 ¯ m - P 4 2 /mnm transition was detected and the interface between Fm 3 ¯ m and P42/mnm structures was coherent, so no crack was found until the end of the simulation with strain of 25% in direction.

The elastic anisotropic, band structure, optical and lattice dynamical properties of ZnGeP2 have been investigated via density functional theory and density functional perturbation theory. The calculated lattice constants and elastic constants of ZnGeP2 are in good agreement with the previous results. The anisotropy in elasticity has been visualized by three-dimensional surfaces and the planar projection contours. ZnGeP2 shows an obvious elastic anisotropy under zero pressure, and the anisotropy increases with the increase in pressure. The hybrid functional HSE06 is used to evaluate the electronic properties of ZnGeP2, and the results suggests that the HSE06 hybrid functional can obtain more reasonable band structure. ZnGeP2 shows direct band gap of 2.06 eV. In addition, the optical spectrum is derived for photon energies up to 40 eV. The phonon frequencies at the Brillouin zone center are calculated and discussed.

All-sky meteor radars are primarily used for meteor observations. This paper reports the first observations of ionospheric E-region field-aligned irregularities (FAIs) from a conventional all-sky meteor radar located at Wuhan (31°N, 114°E) for the period of March–June 2018. E-region FAI echoes evident in range-time intensity (RTI) maps show quasiperiodic striations with positive and negative slopes, which are consistent with multiple FAI structures moving across the wide beam of the meteor radar. A statistical analysis shows that out of a total of 111 d, there are 73 d with E-region FAI echoes detected by the meteor radar. The FAI events correspond well with the presence of sporadic-E layers which provide the necessary plasma density gradient for the development of gradient drift instability producing FAIs. The results demonstrate the capability of conventional meteor radars to make simultaneous routine observations of meteors and ionospheric E-region FAIs through incorporating RTI and spectral analysis into the online realtime data processing. Meteor radar observations could potentially address the limitations of ionospheric radars, which cannot provide simultaneous measurements of neutral winds and irregularity structures, and thereby contribute to better understanding of the dynamical processes producing E-region irregularities.

Three new perovskite-like hybrid iodobismuthates with two quaternary ammonium cations, namely (BnNEt3)3(Bi2I9) (1) (BnNEt3)4(Bi4I16) (2) and (n-Bu4N)2n(Bi4I14)n (3) (Bn = benzyl, n-Bu = n-butyl), have been synthesized by reacting BiI3 with the quaternary ammonium iodide in molar ratio 2:3 (1), 1:1(2), and 2:1 (3), respectively. All hybrids were characterized by elemental analysis, X-ray diffraction and UV–Vis spectroscopic analysis. Single-crystal X-ray diffraction revealed that hybrids 1 and 2 are di-nuclear and tetra-nuclear cluster structures respectively, while 3 is a polymeric chain structure based on a (Bi4I14) tetra-nuclear cluster unit. Their optical band-gaps have been determined as 2.19 eV(1), 2.16 eV(2), 2.02 eV(3), respectively. The optical band gaps exhibit a structure-related decrease from 1 to 3, in agreement with their color changes and the density functional theory (DFT) calculation results. The DFT calculations also reveal that there is a inversely proportional relationship between the optical Eg and the aggregation degree of the BiI6 octahedra in the hybrid iodobismuthate clusters.

The design of highly efficient non-noble-metal electrocatalysts for large-scale hydrogen production remains an ongoing challenge. We report here a Ni2P nanoarray catalyst grown on a commercial Ni foam substrate, which demonstrates an outstanding electrocatalytic activity and stability in basic electrolyte. The high catalytic activity can be attributed to the favorable electron transfer, superior intrinsic activity, and the intimate connection between the nanoarrays and their substrate. Moreover, the unique "superaerophobic" surface feature of the Ni2P nanoarrays enables a remarkable capability to withstand internal and external forces and release the in situ generated H2 bubbles in a timely manner at large current densities (such as >1000 mA cm-2) where the hydrogen evolution becomes vigorous. Our results highlight that an aerophobic structure is essential to catalyze gas evolution for large-scale practical applications.

Spectral polarimetry has the potential to be used to study microphysical properties in relation to the dynamics within a radar resolution volume by combining Doppler and polarimetric measurements. The past studies of spectral polarimetry have focused on using radar measurements from higher elevation angles, where both the size sorting from the hydrometeors’ terminal velocities and polarimetric characteristics are maintained. In this work, spectral polarimetry is applied to data from the 0° elevation angle, where polarimetric properties are maximized. Radar data collected by the C-band University of Oklahoma Polarimetric Radar for Innovations in Meteorology and Engineering (OU-PRIME) during a hailstorm event on 24 April 2011 are used in the analysis. The slope of the spectral differential reflectivity exhibits interesting variations across the hail core, which suggests the presence of size sorting of hydrometeors caused by vertical shear in a turbulent environment. A nearby S-band polarimetric Weather Surveillance Radar-1988 Doppler (KOUN) is also used to provide insights into this hailstorm. Moreover, a flexible numerical simulation is developed for this study, in which different types of hydrometeors such as rain and melting hail can be considered individually or as a combination under different sheared and turbulent conditions. The impacts of particle size distribution, shear, turbulence, attenuation, and mixture of rain and melting hail on polarimetric spectral signatures are investigated with the simulated Doppler spectra and spectral differential reflectivity.

The “self-homing” of cancer cells to primary or metastatic tumor sites indicates that they could serve as vehicles for self-targeted cancer therapy; this suggests a promising method for treating end-stage cancer. Inspired by this, we propose that engineering cancer cells to carry efficient “coup” molecules for in situ activation of immune cells in or near tumor sites to attack tumors is a promising strategy for cancer therapy. Therefore, herein we explored the potential of engineered tumor cells to enhance their anticancer activity by stimulating immune cells. We armed tumor cell surfaces with specific glycopolymer–ligands that bind to lectins on macrophages or dendritic cells by combining HaloTag protein (HTP) fusion technique with reversible addition–fragmentation chain transfer (RAFT) polymerization. We demonstrated that two synthetic well-defined glycopolymers containing, respectively, N-acetylglucosamine and N-acetylmannosamine units, were introduced and stably presented on the cell surfaces via the ...

The Global Ultraviolet Imager (GUVI) aboard the Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) satellite senses far ultraviolet airglow emissions in the thermosphere. The retrieved altitude profiles of thermospheric neutral density from GUVI daytime limb scans are significant for ionosphere-thermosphere study. Here, we use the profiles of the main neutral density to derive the total mass density during the period 2002-2007 under geomagnetic quiet conditions (ap < =12). We attempt to compare the obtained total mass density with the Challenging Minisatellite Payload (CHAMP) observations, making use of an empirical model (GUVI model hereafter). This GUVI model is aimed to solve the difficulty of the direct comparison of GUVI and CHAMP observations due to their different local times at a given location in a given day. The GUVI model is in good agreement with CHAMP observations with the small standard deviations of their ratios (less than 10%) except at low solar flux levels. The correlation coefficients are greater than 0.9, and the relative standard errors are less than 20%. Comparison between the GUVI model and CHAMP observations during solar minimum shows a large bias (similar to 30%). The large bias at low solar flux levels might be due to the limitation of F-10.7 as an extreme ultraviolet radiation flux proxy and the fitting method. Our results demonstrate the validity and accuracy of our model based on GUVI data against the density data from the CHAMP satellite.

The effects of silicon (Si) on the release of tritium over lithium titanate (Li2TiO3) surface (001) are investigated using periodic density functional theory (DFT) calculations. DFT results show th...

We investigated the effect of Pd and Ni dopants on the formation and desorption of tritiated water (T2O) molecules from the Li2TiO3 (001) surface using first-principles calculations coupled with the climbing-image nudged elastic band method. We calculated the energy barriers for T2O production and desorption on the pure Li2TiO3 surface to be 0.94 and 0.64 eV, respectively. The Pd and Ni dopants enhanced T2O formation by reducing the formation energy of O vacancies, and T2O generated spontaneously on the dopant surface. Moreover, we found that dopant atoms affect the charge transfer of neighboring atoms, which leads to orbital hybridization and the generation of a chemical bond between the O and T on the doped Li2TiO3 surface. In addition, desorption of T2O from the doped Li2TiO3 surface requires a relatively low energy (

The interactions of dopants with point defects such as that between vacancies and helium can affect helium evolution and ultimately the macroscopic properties of materials. Herein, the microscopic vacancy trapping mechanism for He defects and the formation of small HemVacn (consisting of m He atoms and n vacancies) clusters in pure and Ti-doped ZrCo systems are investigated by carrying out an extensive set of first-principles calculations based on density functional theory. Our results uncover the following: the helium atom can segregate from the adjacent interstitial (tetrahedral and octahedral) sites towards the vacancy center spontaneously, and therefore, a single He atom is energetically favorable to occupy a vacancy whether in the pure or in the doped system. The dopant Ti can act as a trapping center for He impurities similar to a vacancy. Moreover, it can improve the trapping ability and increase the trapping radius of the vacancies for helium. As for the effect of the Ti atom on the trapping of multiple helium atoms by the vacancy, the higher barrier in the doped systems than in the pure one implies that doping inhibits the formation of large HemVac clusters. Furthermore, in order to evaluate the effect of dopant Ti on the stability of He atoms in multiple vacancies, the binding energies of a helium atom, a vacancy (Vac), and a self-interstitial atom (SIA) to a helium–vacancy cluster (HemVacn) were obtained and compared with that of the pure system. The results suggest that the cluster growth can be inhibited by the dopant Ti, and therefore, the formation of large helium bubbles is also hindered. All the binding energies do not depend much on the cluster size but primarily on the helium-to-vacancy ratio (m/n) of the clusters. The stability of the clusters is decided by the competitive processes among the emission of He atoms, vacancies, and SIAs, and also depends on the helium-to-vacancy ratio. The present results provide an in-depth explanation for the effect of the dopant on helium behavior and could aid future tritium storage material design.

The structural parameters, mechanical, dynamic, and thermodynamic properties of WSi2 with the C11b structure under pressure were systematically explored by using first-principles calculations. The results shown that calculated lattice constants and elastic constants of WSi2 were consistent with previous experimental findings and theoretical values. Our obtained elastic constants revealed that WSi2 was mechanically stable from 0 to 100 GPa. The values of anisotropic indexes, three-dimensional surface constructions, and two-dimensional projections under pressure indicated that WSi2 showed mechanical anisotropy. Additionally, the phonon density of state and phonon dispersion curves under pressure were obtained, and all vibration modes were analyzed. Finally, thermodynamic properties were also predicted based on quasi-harmonic approximation.

The self-assembly of chiral metal nanoclusters into supramolecular chiral aggregates is of interest for developing advanced materials. Herein, we manipulated the self-assembly of Au nanoclusters modified by l-/d-cysteine (l-/d-AuNCs) into ordered microstructures featuring enhanced phosphorescence and optical activities. The formation of these aggregates was driven by synergistic effect of coordination and electrostatic interactions assisted by Cd2+/H+. Detailed structural characterization and theoretical studies confirmed that the compact aggregation structures are essential for the emission enhancement and the chirality amplification of l-/d-AuNCs. Interestingly, upon the formation of microflowers, the emission lifetime was prolonged to 3.34 ms with a switch from fluorescence to phosphorescence induced by aurophilic Au(I)···Au(I) interactions and intensive ligand-to-metal charge transfer (LMCT). Moreover, both the CD and photoluminescence (PL) signals of the microflowers exhibited pH-responsiveness. This dual-mode sensitive platform could be developed as a pH sensor with improved accuracy. Additionally, the pH-responsive photoluminescence ON/OFF switch of the microflowers could be employed for reliable information encryption and decryption. This study provides useful ideas for regulating the self-assembly of nanoclusters to generate desired photophysical properties with potential applications.

Hydrogen economy has emerged as a very promising alternative to the current hydrocarbon economy, which involves the process of harvesting renewable energy to split water into hydrogen and oxygen and then further utilization of clean hydrogen fuel. The production of hydrogen by water electrolysis is an essential prerequisite of the hydrogen economy with zero carbon emission. Among various water electrolysis technologies, alkaline water splitting has been commercialized for more than 100 years, representing the most mature and economic technology. Here, the historic development of water electrolysis is overviewed, and several critical electrochemical parameters are discussed. After that, advanced nonprecious metal electrocatalysts that emerged recently for negotiating the alkaline oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are discussed, including transition metal oxides, (oxy)hydroxides, chalcogenides, phosphides, and nitrides for the OER, as well as transition metal alloys, chalcogenides, phosphides, and carbides for the HER. In this section, particular attention is paid to the catalyst synthesis, activity and stability challenges, performance improvement, and industry-relevant developments. Some recent works about scaled-up catalyst synthesis, novel electrode designs, and alkaline seawater electrolysis are also spotlighted. Finally, an outlook on future challenges and opportunities for alkaline water splitting is offered, and potential future directions are speculated.

In the present study, carbon-dots (CDs) were derived from the thermal oxidation of an agricultural waste, bitter tea residue, to obtain different sp2/sp3 ratios and electronic structures for metal sensing. The CDs obtained from calcination at 700 °C exhibited the highest photoluminescence (PL) quantum yield (QY) of 11.8% among all the samples treated at different temperatures. These CDs had a high degree of graphitization, which resulted in a strong π-π* electron transition, and hence in a high QY. The strong photoluminescence of the CDs could be used to sense the metal ions Ag+, Sr2+, Fe2+, Fe3+, Co2+, Ni2+, Cu2+, and Sn2+ by monitoring their PL intensity at an excitation wavelength of 320 nm. The metals inhibited the PL intensity in the order Ag+ > Fe2+, Fe3+, Ni2+ > Sr2+, Co2+, Cu2+, Sn2+, which demonstrated that the CDs exhibited high metal ion detection capability and selectivity. The detection of Fe3+ using CDs was performed in the range of 10–100 ppm with a LOD (limit of detection) value of 0.380 ppm. Theoretical calculations demonstrated that Ag+, Sr2+, and Sn2+ induced charge transfer excitation and that Fe2+ and Ni2+ induced d-d transitions via complexation with the sp2 clusters. The charge transfer excitation and d-d transitions hindered the π-π* transition of the sp2 clusters, leading to a quenching effect. On the other hand, Li+, Na+, and K+ ions did not alter the π-π* transition of the sp2 clusters, resulting in a negligible quenching effect. In summary, the oxidation level and electronic structure of CDs derived from bitter tea residue could be tailored, and the CDs were shown to be a facile, sustainable, and eco-friendly material for metal sensing.

Tough hydrogels that are capable of efficient mechanical energy dissipation and withstanding large strains have potential applications in diverse areas. However, most reported fabrication strategies are performed in multiple steps with long-time UV irradiation or heating at high temperatures, limiting their biological and industrial applications. Hydrogels formed with a single pair of mechanisms are unstable in harsh conditions. Here we report a one-step, biocompatible, straightforward and general strategy to prepare tough soft hydrogels in a few tens of seconds under mild conditions. With a multimechanism design, the network structures remarkably improve the mechanical properties of hydrogels and maintain their high toughness in various environments. The broad compatibility of the proposed method with a spectrum of printing technologies makes it suitable for potential applications requiring high-resolution patterns/structures. This strategy opens horizons to inspire the design and application of high-performance hydrogels in fields of material chemistry, tissue engineering, and flexible electronics., Tough hydrogels capable of efficient mechanical energy dissipation are difficult to be patterned and/or printed which limits their application. Here the authors show a one-step, biocompatible and general strategy to prepare tough soft hydrogels with high-resolution 2D/3D microstructures quickly under mild conditions.

Hydroxide exchange membrane fuel cells offer possibility of adopting platinum-group-metal-free catalysts to negotiate sluggish oxygen reduction reaction. Unfortunately, the ultrafast hydrogen oxidation reaction (HOR) on platinum decreases at least two orders of magnitude by switching the electrolytes from acid to base, causing high platinum-group-metal loadings. Here we show that a nickel-molybdenum nanoalloy with tetragonal MoNi4 phase can catalyze the HOR efficiently in alkaline electrolytes. The catalyst exhibits a high apparent exchange current density of 3.41 milliamperes per square centimeter and operates very stable, which is 1.4 times higher than that of state-of-the-art Pt/C catalyst. With this catalyst, we further demonstrate the capability to tolerate carbon monoxide poisoning. Marked HOR activity was also observed on similarly designed WNi4 catalyst. We attribute this remarkable HOR reactivity to an alloy effect that enables optimum adsorption of hydrogen on nickel and hydroxyl on molybdenum (tungsten), which synergistically promotes the Volmer reaction., The lack of efficient and cost-effective catalysts for hydrogen oxidation reaction (HOR) hampers the application of hydroxide exchange membrane fuel cells. Here, authors reported bimetallic MoNi4 and WNi4 nanoalloys with marked HOR activity in alkali, among which MoNi4 outperforms the Pt/C catalyst.

Existing electronic skin (e-skin) sensing platforms are equipped to monitor physical parameters using power from batteries or near-field communication. For e-skins to be applied in the next generation of robotics and medical devices, they must operate wirelessly and be self-powered. However, despite recent efforts to harvest energy from the human body, self-powered e-skin with the ability to perform biosensing with Bluetooth communication are limited because of lack of a continuous energy source and limited power efficiency. Here, we report a flexible and fully perspiration-powered integrated electronic skin (PPES) for multiplexed metabolic sensing in situ. The battery-free e-skin contains multimodal sensors and highly efficient lactate biofuel cells that use a unique integration of zero- to three-dimensional nanomaterials to achieve high power intensity and long-term stability. The PPES delivered a record-breaking power density of 3.5 milliwatt-centimeter(−2) for biofuel cells in untreated human body fluids (human sweat) and displayed a very stable performance during a 60-hour continuous operation. It selectively monitored key metabolic analytes (e.g., urea, NH(4)(+), glucose, and pH) and the skin temperature during prolonged physical activities and wirelessly transmitted the data to the user interface using Bluetooth. The PPES was also able to monitor muscle contraction and work as a human-machine interface for human- prosthesis walking.

We have measured the properties of scintillation light in liquid argon doped with xenon concentrations from 165 ppm to 10,010 ppm using a $^{22}$Na source. The energy transfer processes in the xenon-doped liquid argon are discussed in detail, and a new waveform model is established and used to fit the average waveform. The time profile of the scintillation photon in the xenon-doped liquid argon and of the TPB emission are presented. The quantities of xenon-doped are controlled by a Mass Flow Controller which is calibrated via a Redusial Gas Analyzer to ensure that the xenon concentration is accurate. In addition, a successful test of $^{83{\rm m}}$Kr as a calibration source has been implemented in the xenon-doped liquid argon detector for the first time. By comparing the light yield of the $^{22}$Na and $^{83{\rm m}}$Kr, it can be concluded that the scintillation efficiency is almost same over the range of 41.5 keV to 511 keV., Comment: 17 pages, 16 figures

Codonopsis pilosula is a kind of traditional Chinese medicine used to treat weak spleens, stomach problems, anemia, and fatigue. Polysaccharide is one of main components of Codonopsis pilosula. In this study, response surface methodology (RSM) was used to optimize the extraction parameters of Codonopsis pilosula polysaccharides (CPP) by fermentation. The exaction temperature (°C), yeast liquid volume (2 mg/ml, ml), and time (h) were employed effects. Results indicated that the best extraction conditions were the following: extraction temperature 24.75°C, yeast liquid volume 2.96 ml (5.92 mg), and a fermentation time of 21.03 hr. After purification with DE52 and Sephadex G-100, the molecular structure was determined by ultraviolet-visible (UV) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and nuclear magnetic resonance (NMR) (1H and 13C). The monosaccharide composition of CPP1 was determined to be mannose (1.76%), glucose (97.38%), and arabinose (0.76%). CPP1 exhibited high antioxidant activities in scavenging ABTS radicals, ferreous ions, and superoxide ion radicals. Thus, CPP1 could be used as an antioxidant or functional food.

This paper demonstrated the fabrication of a facile, low-cost, and self-powered platform for point-of-care fitness level and athletic performance monitoring sensor using electrochemical lithography method and its application in body fluid sensing. Flexible Au/prussian blue electrode was employed as the indicating electrode, where the color change was an indication of fitness level and athletic performance. A piece of Al foil, Au/multiwalled carbon nanotubes (MWCNTs)-glucose dehydrogenase, and Au/polymethylene blue-MWCNTs-lactic dehydrogenase electrodes were used for the detection of ionic strength, glucose, and lactic acid in sweat, respectively, which allows the sensor to work without any extra instrumentation and the output signal can be recognized by the naked eyes. The advantages of these sensors are (1) self-powered; (2) readily applicable to the detection of any electroactive substance by an electrochromic material; (3) easy to fabricate via two steps of EDP; and (4) point-of-care. By assembling the energy and sensing components together through a transparent adhesive tape, the proposed self-powered wearable biosensor exhibits superior performances, indicating its broad applied prospect in the point-of-care diagnoses.

A series ofN-acyl glucosamine-bearingtriterpenoidsaponins has been synthesized with cytotoxic activities evaluated against HL-60, PC-3, HCT-116, and CT-26 tumor cells. Saponins incorporated anoleanolic acid (OA) triterpenoidal core exhibited the highest cytotoxic activity. To study the influence of the lengths of acyl-carbon chain onN-position of glucosamine, cells were treated with28-propargylamides and then reacted with an azido-fluorogenic probe under CuAACclickreactions to visualize the intact distributions of these compounds by confocal microscopy and flow cytometry; it was found that cytotoxic-active compounds (30-32) located in the cytosol and inactivecompounds bearing longer carbon chains (33-35) were impenetrable across cell membranes.Our study demonstrated the defined lipophilic acyl-carbon chain length can precisely regulate thecytotoxic activityof saponins, which is useful for the future development of cytotoxic agents.Furthermore, using quantitative proteomics and immunolabeling,the mechanism ofcytotoxicity induced by the synthetic saponin after membrane penetration could be a result of activation of death receptor pathway and inhibition of PI3K/Akt/mTOR pathway.

Economical and abundant natural biological materials provide a low-cost and scalable approach to develop next-generation flexible and wearable electronics. Herein, a universal strategy of nature-inspired and amine-promoted metallization, namely, NIAPM, is presented to make high-quality metals for electronics fabrication. The introduction of poly(ethyleneimine) (PEI) significantly shortens the time of metallization from >48 h to ≈6 h, and the phenol compounds (TP) from green tea make metals bond tightly on all demonstrated surfaces. The as-made thin metal films of Cu and Ni feature high conductivity (∼1.0 Ω/□), excellent mechanical stability and flexibility even at the bending radius of ∼1 mm. Moreover, NIAPM is compatible with typical lithography techniques for fabricating metallic patterns, showing considerable potential applications in flexible electronics. As a proof-of-concept, two devices based on melamine-templated Cu sponges are first prepared for detecting the change of external pressure with a resistance sensitivity of 18.1 kPa-1 and collecting high-viscosity crude oil, respectively. Then, a high-performance bendable solid supercapacitor is demonstrated using as-prepared Ni metallized fabrics and the activated porous carbon from the recycled waste in NIPAM as flexible electrodes, which possesses comparable areal capacitance of 45.5 F·g-1, and energy density of 7.88 Wh·g-1 at the power density of 35 W·g-1. Therefore, it is anticipated that such a time-saving, cost-effective and whole solution-processed NIAPM strategy can inspire further practical applications in the fields of surface chemistry, material science, flexible and wearable electronics, etc.

The potential energy curves and dipole moments for the lowest seven Λ − S states correlating to three dissociation limits Si + ( P 2 u ) + H ( S g 2 ) , Si + ( P g 4 ) + H ( S g 2 ) , and Si ( D g 1 ) + H + ( S g 1 ) of SiH+ cation are computed using multi-reference configuration interaction plus Davidson corrections method with the AWCV5Z-DK basis set. By solving the radical Schrodinger equation, the spectroscopic parameters of these states are obtained, which are in excellent agreement with available experimental values. The spin-orbit coupling effect is taken into account in the computations via the Breit-Pauli Hamiltonian operator, which causes the seven Λ − S states to split into fifteen Ω states. It is the first time that the spin-orbit coupling calculation is carried out on SiH+. The spin-orbit coupling leads to avoided crossing between B 1 Δ 2 and d Π 2 3 states, c 3 Σ 1 − and b Σ 1 + 3 states, respectively. The B 1 Δ 2 state has a double-well potential resulting from the avoided crossing. The potential energy curves and spectroscopic constants of the Ω electronic states are also depicted with the aid of the avoided crossing between electronic states of the same symmetry. In addition, the transition dipole moments, Franck-Condon factors and the radiative lifetimes for the X Σ 1 ↔ A Π 1 , A Π 1 ↔ B Δ 1 , a Π 3 ↔ d Π 3 , a Π 3 ↔ c Σ − 3 , c Σ − 3 ↔ d Π 3 , X Σ 0 + + 1 ↔ a Π 0 + 3 , and X Σ 0 + + 1 ↔ a Π 1 3 transitions are obtained.

The transition metal oxides based catalysts have drawn great attention for their application in the electrolysis of water for renewable energy generation. Although manganese oxides were rarely used as oxygen evolution reaction (OER) catalysts, they were still considered as active and efficient OER catalysts due to the earth-abundant and low toxic nature of manganese. In this work, we proposed a facile method for the synthesis of high-performance electrochemical OER catalyst by magnetically stirring the mixture of 1,3,4-thiadiazole-2,5-dithiol (DMTD), Ni2+ and MnO2 nanowires (NWs) in ethanol at room temperature, noted as Ni/DMTD/MnO2. The Ni/DMTD complex and MnO2 NWs showed synergistically enhanced OER activity and excellent durability in alkaline solution. The introducing of MnO2 and the presence of Ni3+ after the oxidation of Ni2+ were the key factors which improve the OER performance. The potential at 10 mA cm-2 was 1.492 V (vs RHE) with a Tafel slope of 69.46 mV dec-1 in 1 M KOH aqueous solution, comparable to the state-of-art RuO2. The results indicated that MnO2 was found to have the capability to enhance not only the catalytic activity but also operation stability of Ni/DMTD/MnO2 towards OER.

Carbon aerogels with 3D networks of interconnected nanometer-sized particles exhibit fascinating physical properties and show great application potential. Efficient and sustainable methods are required to produce high-performance carbon aerogels on a large scale to boost their practical applications. An economical and sustainable method is now developed for the synthesis of ultrathin carbon nanofiber (CNF) aerogels from the wood-based nanofibrillated cellulose (NFC) aerogels via a catalytic pyrolysis process, which guarantees high carbon residual and well maintenance of the nanofibrous morphology during thermal decomposition of the NFC aerogels. The wood-derived CNF aerogels exhibit excellent electrical conductivity, a large surface area, and potential as a binder-free electrode material for supercapacitors. The results suggest great promise in developing new families of carbon aerogels based on the controlled pyrolysis of economical and sustainable nanostructured precursors.

Preparing an autonomous self-healing supramolecular elastomer with sunlight degradability is still a challenging task in related fields. In this work, we report a supramolecular elastomer by using the classic host–guest complexation of visible-light-photolabile picolinium-containing adamantanes (Ad) and β-cyclodextrin nanogels (β-CD). The as-synthesized elastomer possesses merits of high mechanical strength, excellent stretchability (>1500% strain), efficient self-healing (>85% at 60 min), ultrastability against electrolytes, and photodegradation properties, implying versatile applications in flexible and stretchable electronics. As proofs-of-concept, self-healable strain and pressure sensors using conductive elastomers are first fabricated, which feature exceptionally high sensitivity (e.g., 0.1% in capacitance at 0.2 kPa) and fast response to detect human body motions. A degradable and flexible supercapacitor is also fabricated using the conductive elastomer as the flexible matrix. Remarkably, both the ...

This study examines the utility of the N-benzylcarbamoyl (BnCar) protecting group in glycosylation reactions of the parent O-2 protected carbohydrate donor. It was found that the BnCar group imparted exclusively β-selectivity with primary and secondary alcohols. A mechanistic study revealed the activated intermediate to be the glycosyl triflate in a skew conformation, which results in β-selective glycosylation via an SN2-like pathway. The BnCar group can be readily cleaved using tetrabutylammonium nitrite, without affecting ester and ether protecting groups. Taken together, these results show BnCar to be useful for the synthesis of complex oligosaccharides, an undertaking that requires delicate chemical differentiation of various protecting groups.

The possibility of laser cooling the 24Mg35Cl molecule is investigated using the electronic, rovibrational, and hyperfine structure. Twelve low-lying Λ–S electronic states of the 24Mg35Cl molecule have been calculated at the multireference configuration interaction level of theory. The spin–orbit coupling effects are taken into account in the electronic structure calculations. Spectroscopic constants agree well with previously obtained theoretical and experimental values. On the basis of the potential energy curves and transition dipole moments, the highly diagonally distributed Franck–Condon factors for the A2Π → X2Σ+ transition and short radiative lifetime of the A2Π state are determined. Then, employing a quantum effective Hamiltonian approach, we investigate the hyperfine manifolds of the X2Σ+ state and obtain the zero-field hyperfine spectrum with the errors relative to the experimental data not exceeding 8–20 kHz. Finally, we design a laser cooling scheme with one cooling main laser beam and two rep...

The complex permittivity and return loss (RL) for the composites of silicone rubber filled with holey graphene nanosheets (HGNS, prepared by ultra-rapid heating during the step of thermal reduction/exfoliation of graphite oxide) were measured in the 3–18 GHz range. HGNS-based composites were found to have significantly higher microwave absorption than composites incorporating other types of graphene reduced at lower heating rates. Even with only 1 wt.% loading, its experimentally measured RL reached −32.1 dB at 13.2 GHz with a thickness of 2 mm, and simulation suggested that at a thickness of 3 mm its RL can be as low as −45.3 dB at 7.8 GHz. Material characterization indicated that the density of the holes increased with the temperature ramp rate, and the hole sizes ranged from 5 to 300 nm. Compared to other graphene samples, HGNS possessed significantly larger specific surface area and higher density of defects, suggesting that defect-induced losses, interfacial polarization, and multiple reflection/scattering at the interfaces are the major loss mechanisms. Our simple and low-cost process as well as the very low loading ratio of HGNS are advantageous for cost reduction in future applications.

A bio-photoelectrochemical cell (BPEC) based on a fuel-free self-circulation water-oxygen-water system was fabricated. It consists of Ni:FeOOH modified n-type bismuth vanadate (BiVO4 ) photoanode and laccase catalyzed biocathode. In this BPEC, irradiation of the photoanode generates photocurrent for photo-oxidation of water to oxygen, which is reduced to water again at the laccase biocathode. Of note, the by-products of two electrode reactions could continue to be reacted, which means the H2 O and O2 molecules are retained in an infinite loop of water-oxygen-water without any sacrificial chemical components. As a result, the assembled fuel-free BPEC exhibits good performance with an open-circuit potential of 0.97 V and a maximum power density of 205 μW cm-2 at 0.44 V. This BPEC based on a self-circulation system offers a fuel-free model to enhance multiple energy conversion and application in reality.

The adsorption and dissociation behaviors of molecular H2O on the Li4SiO4 (0 1 0) surface have been systematically studied by first-principles calculations. It is found that the adsorbed H2O molecule mainly interacts with the O and Li atoms of the surface, that is, H atom bonds with O atoms of the surface while O atom bonds with the surface Li atoms due to the hydrogen bond effect. According to the different adsorption energies and vibrational frequencies of H2O, different adsorption types can be classified. These results may explain the origin of multiple desorption peaks in TDS experiments.