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Intentional electromagnetic interference is a serious threat to the safety of electronic devices. Multiple electromagnetic pulses will be coupled and transmitted to electronic devices through the cables. Accumulative effects are generated, which make it easier for damage to occur in the electronic devices. In this article, the working principle of micro-silicon acceleration sensors is introduced. The accumulative effects of multiple pulses on acceleration sensors is studied by a large number of injection experiments. The accumulation trends of multiple pulses with different pulse numbers and intervals are analyzed. The damaged structures inside abnormal sensor amplifiers were observed via optical microscopy and scanning electron microscopy. The experimental results show that the accumulative effect is strengthened with increased pulse number or decreased pulse interval, and the threshold voltage for multiple pulses on the acceleration sensor decreases. The threshold voltage for a single pulse is 321.57 V. When the pulse interval is 1 μs and the pulse number is 5, the threshold voltage for multiple pulses is 163.42 V, which is reduced by 49.12% compared with a single pulse. These results provide a reference for the damage design of electromagnetic pulse weapons.

Volatile organic compounds (VOCs) which exist widely in indoor air, are confirmed to be harmful to human health. In this study, gaseous toluene, the representative VOCs, was degraded by photo-catalytic oxidation (PCO) under visible light. The Ag3PO4-g-C3N4 composites with different weight ratios of Ag3PO4/g-C3N4 were synthesized and used as the photo-catalysts. The results indicated that the Ag3PO4-g-C3N4 composites with the weight ratio of 2.6 % exhibited the most superior photo-catalytic activity, and the removal efficiency of toluene was 87.52 % within 100 min irradiation, which was higher than that of bare g-C3N4 and Ag3PO4. The pseudo-one-order model was applied to analyzing the reaction process, and the apparent reaction rate constant of 2.6 %-APO-g-C3N4 was 0.005 min−1. After 3 cycles, the removal efficiency was still higher than 80.72 %. According to the results of PLS and ESR, the combination of Ag3PO4 and g-C3N4 could improve photo-induced carrier separation as well as OH and O2− radicals were both detected. Furthermore, the Z-scheme mechanism of Ag3PO4-g-C3N4 photo-catalysts was proposed. Therefore, the superior photo-catalytic activity of composites was significantly increased by the Z-scheme. In addition, the small proportion of Ag3PO4 in composites may be beneficial for a wide range of applications, given the cost of noble metal Ag.

Environmental remediation has become more effective when using nanotechnologies. In this study, iron oxide (α-Fe2O3) nanospheres with different cobalt doping levels (xCo-Fe2O3) were synthesised and applied in the heterogeneous activation of peroxymonosulfate (PMS) for the degradation of p-hydroxybenzoic acid (p-HBA). The catalyst (3Co-Fe2O3) with 3% Co doping exhibits the best performance for PMS activation, possibly because of the larger specific surface area and the tailored catalyst surface as confirmed by X-ray photoelectron spectroscopy (XPS). Reaction parameters were investigated to optimise the degradation efficiency. The metal ions leaching tests confirmed the higher stability of the catalyst, thanks to the leaching suppression by the doping of Co2+. The main contribution of free radicals (SO4•- and •OH) was confirmed by electron paramagnetic resonance (EPR) spectra, whereas partial contribution of oxygen anions and singlet oxygen (O2•-, 1O2) was observed during the quenching tests. Finally, a radical based degradation mechanism was proposed for the removal of p-HBA. It is expected to open up a novel perspective for the application of iron oxide as a potential catalyst for the removal of emerging contaminants.

Fabricating a high-performance adsorbent as a desirable candidate for removing Pb2+ from aqueous water remains a challenge. Aramid nanofibers (ANFs) are promising building blocks that have realized multifunctional applications due to their intrinsic mechanical and chemical stability. Herein, an in situ loading strategy for preparing nanofiber composite aerogel was proposed by assembling ANFs into a 3D aerogel and applying it as host media for the in situ polymerization of pyrrole followed by facile redox reaction between the polypyrrole (PPy) and MnO4–1 to load manganese dioxide (MnO2). The idea was to fully exploit the structural advantages of ultra-low bulk density, large specific surface area, and high porosity of ANFs, and the possible chemical adsorption characteristics of MnO2 on the basis of ion exchange reaction. The adsorption capacity of 3D ANF/MnO2 composite aerogel was as large as 554.36 mg/g for Pb2+. The adsorption mechanism based on an exchange reaction between Pb2+ and protons on the surface of MnO2 was also investigated. The desorption results showed that the adsorption performance could remain up to 90% after five times of usage. In conclusion, this research provides promising insights into the preparation of high-performance lead adsorbent for water treatment.

The recent materialization carbyne confined to double-walled carbon nanotubes represents a major breakthrough in materials science but the control of its properties remains a major challenge. Here, localized photothermal heating through laser annealing and the possibility to perform Raman spectroscopy in-situ allow fabricating confined carbyne with tailored properties. Transmission electron microscopy shows the confined carbyne can reach about 10 nm in length. Evident interaction between the nanotubes and the confined carbyne alters the tube's diameter. Furthermore, the mechanism to tailor the properties of the confined carbyne could be associated to its corresponding Raman mode. The evolution of the synthesis constricted to the tube under increasing laser power can be monitored step by step from the moment the growth starts until a knock-off threshold is reached. Photothermal annealing represents a real possibility to synthesize carbyne confined to single-chirality carbon nanotubes, which is not entirely feasible otherwise.

Global Climate is one chapter from the State of the Climate in 2019 annual report and is avail- able from https://doi.org/10.1175/BAMS-D-20-0104.1 Compiled by NOAA’s National Centers for Environmental Information, State of the Climate in 2019 is based on contributions from scien- tists from around the world. It provides a detailed update on global climate indicators, notable weather events, and other data collected by environmental monitoring stations and instru- ments located on land, water, ice, and in space. The full report is available from https://doi.org/10.1175/2020BAMSStateoftheClimate.1.

With the goal of constructing a carbon-free energy cycle, proton-exchange membrane (PEM) water electrolysis is a promising technology that can be integrated effectively with renewable energy resources to produce high-purity hydrogen. IrO2, as a commercial electrocatalyst for the anode side of a PEM water electrolyzer, can both overcome the high corrosion conditions and exhibit efficient catalytic performance. However, the high consumption of Ir species cannot meet the sustainable development and economic requirements of this technology. Accordingly, it is necessary to understand the OER catalytic mechanisms for Ir species, further designing new types of low-iridium catalysts with high activity and stability to replace IrO2. In this review, we first summarize the related catalytic mechanisms of the acidic oxygen evolution reaction (OER), and then provide general methods for measuring the catalytic performance of materials. Second, we present the structural evolution results of crystalline IrO2 and amorphous IrOx using in situ characterization techniques under catalytic conditions to understand the common catalytic characteristics of the materials and the possible factors affecting the structural evolution characteristics. Furthermore, we focus on three types of common low-iridium catalysts, including heteroatom-doped IrO2 (IrOx)-based catalysts, perovskite-type iridium-based catalysts, and pyrochlore-type iridium-based catalysts, and try to correlate the structural features with the intrinsic catalytic performance of materials. Finally, at the end of the review, we present the unresolved problems and challenges in this field in an attempt to develop effective strategies to further balance the catalytic activity and stability of materials under acidic OER catalytic conditions.

In this work, polycrystalline Pr1-xBaxMnO3 (0.25 ≤ x ≤ 0.36) ceramics were synthesized, and their magnetic and electrical transport properties were systematically studied. All samples show two metal-insulator transitions (MITs) corresponding to the high temperature TMI1 and low temperature TMI2, respectively, besides the non-Griffith phase above the ferromagnetic (FM) transition temperature TC. Combining the results of the transport and magnetic properties, it is found that the FM transition temperature TC coincides with the temperature TMI1, which is linearly related to the A-site ionic radius mismatch variance σ2, indicating the enhancement of FM interactions due to the increase of the degree of B-site ordering of Mn3+/Mn4+ ions. The positive correlation between ferromagnetic insulators (FMI) and magnetic interactions, including the FM and short-range antiferromagnetic (AFM) interactions, is confirmed. It is suggested that the first MIT at TMI1 is attributed to the Mn3+/Mn4+ double exchange interactions and the second MIT at TMI2 is closely related to the suppression of the AFM interactions under the internal FM field induced by the Mn3+/Mn4+ DE interactions. This work provides not only a theoretical understanding on the origin of MIT at low temperature, but also a new way for adjusting the FMI in perovskite manganese oxide Pr1-xBaxMnO3 for application.

A new copper(II) metal-organic framework is constructed as a sustainable copper heterogeneous catalyst. Cu-DPTCA, with high catalytic activity, can effectively promote the Chan–Lam coupling reaction of arylboronic acids and amines without adding any base or additive.

Redox mediators (RMs) have been developed as efficient approaches to lower the charge polarization of Li-O2 batteries. However, the shuttle effect resulting from their soluble nature severely damages the battery performance, causing failure of the RM and anode corrosion. In this work, a chemical binding strategy based on a MXene-modified separator with a 3D porous hierarchical structure design was developed to suppress the I3- shutting in LiI-involved Li-O2 battery. As corroborated by experimental characterizations and theoretical calculations, the abundant -OH terminal groups on the MXene surface functioned as effective binding sites for suppressing the migration of I3-, while the 3D porous structure ensured the fast transfer of lithium ions. As a result, the Li-O2 battery with the MXene-modified separator showed no sign of redox shuttling compared with its counterparts in the full discharge/charge tests. In the meantime, the MXene-modified separator based-cell exhibited a stable cycle life up to 100 cycles, which is 3 times longer than the control samples. We believe that this work could provide insights into the development of separator modification for Li-O2 batteries with RMs.

To analyze the effects of freeze-thaw cycles and confining pressure on the mechanical properties of red sandstone, through freeze-thaw cycles and triaxial compression tests, full stress-strain curves of different freeze-thaw cycles and different confining pressures were obtained. The degradation degree of red sandstone was quantitatively considered from different mechanical parameters of ultimate stress, elastic modulus, and Poisson’s ratio. Based on summarizing the characteristics of rock under freeze-thaw and load, the total damage variable of rock was determined by the reasonable measurement of freeze-thaw damage variable and load damage variable, and a damage constitutive model under freeze-thaw and load was established. The research showed that the freeze-thaw cycles aggravate the degree of rock damage deterioration, the rock stiffness and strength were reduced, and the characteristics of plastic deformation and ductile failure were more obvious. The confining pressure inhibited red sandstone internal damage, and with the increase of confining pressure, the stiffness and strength and the plastic characteristics were increased. In the overall trend, the mechanical parameters had different sensitivity to the degradation effect of freeze-thaw cycles and confining pressure. Regardless of the increase in the number of freeze-thaw cycles or confining pressure, the strain softening modulus tended to decrease gradually, and red sandstone plastic damage became more obvious after the stress peak. The total damage evolution path of red sandstone reflected the nonlinear influence of freeze-thaw and load on the total damage propagation. The research results provide theoretical support for the improvement of the technology of the effluent coal rock in Balasu Coal Mine.

The understanding of land-use and land-cover change (LUCC) is crucial for the study of global climate change and the terrestrial ecological environment. Sandy land is an important component of the ...

Aim: Glycopyrrolate (GLY) has been widely used to treat chronic obstructive pulmonary disease (COPD). Recent technical advancement significantly improves the drug delivery efficiency. In a clinical dose-range determination study via electronic nebulizer, the starting dose was as low as 3-μg, thus, a bioanalytical method capable of measuring down to sub-pg/ml or fg/ml level was required to characterize pharmacokinetics of GLY. Methods: A straightforward solid-phase extraction coupled with reversed-phase LC-MS/MS method was successfully developed to quantify plasma GLY concentrations of 0.500–250 pg/mL. MS/MS detection was at ESI+ by monitoring m/z 318.3→116.1 for GLY and 321.3→119.1 for the internal standard GLY-d3. Results and Conclusion: The method was validated with adequate selectivity, intra- and inter-assay precision and accuracy, dilution linearity, and sufficient stability for measuring GLY in human plasma. This method has been used for sample analysis of a clinical dose-range finding study (3–50 µg twice daily doses via an electronic nebulizer). The assay exhibited good precision, accuracy, and robustness. Pharmacokinetic analysis showed good dose proportionality over the studied dose range, where Cmax was found to be Y = 1.354*X + 1.968 (r2 = 0.9984), and AUC0-12 h was Y = 4.661*X + 23.32 (r2 = 0.9976). The study clearly demonstrated the importance of an ultrasensitive (500 fg/ml LLOQ) method.

In a narrow temperature window in going from the isotropic to highly chiral orders, cholesteric liquid crystals exhibit so-called blue phases, consisting of different morphologies of long, space-filling double twisted cylinders. Those of cubic spatial symmetry have attracted considerable attention in recent years as templates for soft photonic materials. The latter often requires the creation of monodomains of predefined orientation and size, but their engineering is complicated by a lack of comprehensive understanding of how blue phases nucleate and transform into each other at a submicrometer length scale. In this work, we accomplish this by intercepting nucleation processes at intermediate stages with fast cross-linking of a stabilizing polymer matrix. We reveal using transmission electron microscopy, synchrotron small-angle X-ray diffraction, and angle-resolved microspectroscopy that the grid of double-twisted cylinders undergoes highly coordinated, diffusionless transformations. In light of our findings, the implementation of several applications is discussed, such as temperature-switchable QR codes, micro-area lasing, and fabrication of blue phase liquid crystals with large domain sizes., The arrangements of defect lines in liquid crystal blue phases provide promising templates for photonic crystals. Here Liu et al. investigate in detail how inter-phase transitions proceed, by intercepting nucleation with on-demand cross linking of a supporting polymer matrix.

AimsBnaC4.BOR1;1c is required for B acquisition in Brassica napus (B. napus) under low B stress. This study aimed to reveal the B regulatory mechanism of BnaC4.BOR1;1c and its physiological roles in B translocation from roots to shoots and B distribution in shoots. MethodsTransgenic Arabidopsis plants expressing GUS (β-glucuronidase) under different promoters were generated and the mRNA, and GUS activity was quantitatively measured. The in-situ PCR and immunohistochemistry in B. napus were performed to investigate BnaC4.BOR1;1c expression pattern and localization. Furthermore, assays of B transport and distribution in wild type B. napus and BnaC4.BOR1;1c RNAi lines were carried out to elucidate its physiological roles. ResultsResults showed that BnaC4.BOR1;1c mRNA abundance is negatively correlated with B availability, which was mediated by the 29 nt sequence in the 5’ terminal region of 5’-UTR. Besides, the 5’-UTR simultaneously regulates protein expression level, most probably depending on the translation efficiency. BnaC4.BOR1;1c mainly localizes on the plasma membrane of vascular bundle cells in roots and shoots with a polar localization manner that is probably beneficial to B xylem loading in roots and B unloading from xylem to phloem in vascular bundle of shoots. Short-term 10B uptake analysis demonstrates that BnaC4.BOR1;1c preferentially distributes B to developing leaves and flowers under B deficiency. ConclusionThis study reveals combined regulatory action of mRNA abundance and translation efficiency mediated by the 5’-UTR in BnaC4.BOR1;1c in response to B availability and its physiological role in preferential B acquisition in developing tissues of B. napus.

Rapeseed (Brassica napus) is an economically important oilseed crop in the world, but its production is strongly dependent on boron (B) supplies. Major intrinsic protein NIP5;1 is essential for B uptake and plant development under B limitation. In this study, phylogenetic and expression analyses identified two NIP5;1 orthologue genes, BnaA2.NIP5;1 and BnaA3.NIP5;1, which are mainly expressed in roots of B. napus. Specific and multiple-target RNAi was used to suppress BnaA3.NIP5;1 or both BnaA2.NIP5;1 and BnaA3.NIP5;1 expression in B-efficient rapeseed Qingyou 10 (QY10), respectively, for revealing the roles of BnaA2.NIP5;1 and BnaA3.NIP5;1 in low-B tolerance in B. napus. We found that both BnaA2.NIP5;1 and BnaA3.NIP5;1 are important for B. napus normal growth under low-B conditions, while these two genes have distinct roles. BnaA2.NIP5;1 is mainly expressed in the epidermis cells, which is required for efficient B uptake into roots, hence for B translocation to the shoots. BnaA3.NIP5;1 is specifically localized in the distal part of lateral root cap cells to promoter root elongation under low-B conditions, which is important for seed production in the maturity stage of B. napus. Taken together, our specific and multiple-target RNAi strategy provides novel insights into the gene function diversification between BnaA2.NIP5;1 and BnaA3.NIP5;1, such an approach can be potentially applicable to other polyploid crops.

Digenite (Cu1.8S) as a potential p-type thermoelectric (TE) material has attracted extensive attention due to its environmental benign, abundant resources and low cost of component elements. In this study, the TE properties of MnxCu1.8S bulk samples prepared by mechanical alloying (MA) combined with spark plasma sintering (SPS) were investigated. Doping Mn would initially substitute Cu and tune the band structure of Cu1.8S with an enlarged band gap Eg. However, if Mn content is beyond the solubility limit of x = 0.01 in Cu1.8S will cause the formation of MnS, which contributes to the formation of Cu-rich phases at 0.02 ≤ x ≤ 0.08. Benefiting from the synergetic scattering effect of point defects ( Mn Cu • , V S • • ) and MnS, Cu1.96S, Cu1.97S, Cu2S phases, the lowest thermal conductivity κ value of 0.75 W m−1K−1 was obtained at 773 K for Mn0.08Cu1.8S. Along with the decreased κ, the highest figure of merit ZT value of 0.92 at 773 K achieved in Mn0.08Cu1.8S bulk sample. A maximum engineering ZTeng of 0.3 and its efficiency ηmax of about 6% were obtained at 323–773 K, which is almost 3 times than that of the pristine Cu1.8S (ηmax = 2.2%). Introducing Mn in Cu1.8S is an effective and convenient strategy to improve TE performance.

A stage structures (scattered and school children) model with temperature-dependent latent period to investigate hand, foot and mouth disease (HFMD) transmission is proposed. The periodic delay induced by latent period in modelling brings new challenges to dynamics analysis. With the help of defined basic reproduction number R 0 , we prove: when R 0 1 , the disease-free equilibrium is globally attractive; when R 0 > 1 , this model is uniformly persistent. Next, the model is applied to simulate the HFMD reported data in Guangxi province, China from January 2018 to December 2019. The simulation results are consistent with our theories, and it also shows that scattered children are the main affected population. Finally, by comparing with time-averaged latent period, numerical experiments analyze the effect of time-varying latent period on HFMD transmission. Based on the HFMD transmission case in Guangxi Province, we find that the use of time-averaged latent period underestimates the real value of R 0 and the number of new infections containing scattered and school children is also underestimated.

Metal–organic frameworks (MOFs) exhibit high proton conductivity, thermal stability, and offer immense flexibility in terms of tailoring their size. Owing to their unique characteristics, they are desirable candidates for proton conductors. Nevertheless, constructing ordered MOF proton channels in proton exchange membranes (PEMs) remains a formidable challenge. Herein, blend nanofibers of cellulose and UiO-66-NH2 (Cell–UiO-66-NH2) obtained via the electrospinning process were embedded in a sulfonated polysulfone matrix to obtain high-performance composite PEMs with an orderly arrangement of UiO-66-NH2. Comprehensive characterization and membrane performance tests reveal that composite membrane with 5 wt% (nominal) UiO-66-NH2 have revealed high proton conductivity of 0.196 S cm−1 at 80 °C and 100% relative humidity. Meantime, the composite membrane exhibits a low methanol permeability coefficient (~5.5 × 10−7 cm2 s−1). Moreover, the composite membrane exhibits a low swelling ratio (17.3%) even at 80 °C. The Cell–UiO-66-NH2 nanofibers exhibit strong potential for use as a proton-conducting nanofiller in fuel-cell PEMs.

Strong metal-support interactions (SMSI) is an important concept in heterogeneous catalysis. Herein, we demonstrate that the Au-TiO2 SMSI of Au/TiO2 catalysts sensitively depends on both Au nanoparticle (NP) sizes and TiO2 facets. Au NPs of ca. 5 nm are more facile undergo Au-TiO2 SMSI than those of ca. 2 nm, while TiO2 {001} and {100} facets are more facile than TiO2 {101} facets. The resulting capsulating TiO2-x overlayers on Au NPs exhibit an average oxidation state between +3 and +4 and a Au-to-TiO2-x charge transfer, which, combined with calculations, determines the Ti:O ratio as ca. 6:11. Both TiO2-x overlayers and TiO2-x -Au interface exhibit easier lattice oxygen activation and higher intrinsic activity in catalyzing low-temperature CO oxidation than the starting Au-TiO2 interface. These results advance fundamental understanding of SMSI and demonstrate engineering of metal NP size and oxide facet as an effective strategy to tune the SMSI for efficient catalysis.

Redox-active organics are investigation hotspots for metal ion storage due to their structural diversity and redox reversibility. However, they are plagued by limited storage capacity, sluggish ion diffusion kinetics, and weak structural stability, especially for K+ ion storage. Herein, we firstly reported the lamellar tetrapotassium pyromellitic (K4 PM) with four active sites and large interlayer distance for K+ ion storage based on a design strategy, where organics are constructed with the small molecular mass, multiple active sites, fast ion diffusion channels, and rigid conjugated π bonds. The K4 PM electrode delivers a high capacity up to 292 mAh g-1 at 50 mA g-1 , among the best reported organics for K+ ion storage. Especially, it achieves an excellent rate capacity and long-term cycling stability with a capacity retention of ≈83 % after 1000 cycles. Incorporating in situ and ex-situ techniques, the K+ ion storage mechanism is revealed, where conjugated carboxyls are reversibly rearranged into enolates to stably store K+ ions. This work sheds light on the rational design and optimization of organic electrodes for efficient metal ion storage.

Li+-conductive ceramic oxide electrolytes, such as garnet-structured Li7La3Zr2O12, have been considered as promising candidates for realizing the next-generation solid-state Li-metal batteries with high energy density. Practically, the ceramic pellets sintered at elevated temperatures are often provided with high stiffness yet low fracture toughness, making them too brittle for the manufacture of thin-film electrolytes and strain-involved operation of solid-state batteries. The ceramic powder, though provided with ductility, does not yield satisfactorily high Li+ conductivity due to poor ion conduction at the boundaries of ceramic particles. Here we show, with solid-state nuclear magnetic resonance, that a uniform conjugated polymer nanocoating formed on the surface of ceramic oxide particles builds pathways for Li+ conduction between adjacent particles in the unsintered ceramics. A tape-casted thin-film electrolyte (thickness

The generalized method of moments (GMM) is an important estimation procedure in many areas of economics and finance, and it is well known that this estimation is highly sensitive to the presence of outliers and influential observations. Case-deletion diagnostic has been studied in GMM estimation; however, it is surprised that local influence analysis is under explored. To this end, a local influence method is proposed to assess the effect of minor perturbation on GMM estimation. The local diagnostic measures of GMM estimators under the perturbations of empirical distribution and moment condition are derived to study the joint influence of observations. The obtained results are applied to efficient instrumental variable estimation and dynamic panel data model. Two real data sets are used for illustration, and a simulation study is conducted to examine the effectiveness of the proposed methodology. The advantage of local influence method is analyzed in detail through comparison with the case-deletion method.

Four novel stilbene dimers (1-4), together with their biosynthetically related stilbene monomers (5 and 6), were isolated from the leaves of Cajanus cajan. Their structures with absolute configurations were determined by comprehensive analysis of spectroscopic data and electronic circular dichroism calculations. Compounds 1 and 2 are two novel dimeric stilbenes with an unusual coupling pattern that resulted in a rare configurationally stable Csp2-Csp3 chiral axis with both point and axial chirality in their molecules. Due to their unique inherent structural features, both of them naturally occur as equilibrating mixtures of unequally populated atropo-diastereomers and their respective enantiomers. Compounds 3 and 4 are two pairs of novel dimeric stilbene atropisomers featuring a rotationally hindered central biaryl axis. Notably, 3 contains a rare arylbenzoquinone core and 4 is a symmetric dimer with a C2 symmetry axis. The hypothetical biosynthetic pathway of 1-4 was also proposed herein. All the new compounds exhibited significant protein tyrosine phosphatase-1B (PTP1B) inhibition effects. In addition, the preliminary mode of action for the most potent compound 3 was investigated by molecular docking and binding free energy calculation.

The R-dependent structural and magnetic properties of the disordered RFe0.5Cr0.5O3 (R = Ce, Pr, Nd, Sm) ceramics are systemically investigated. Based on the model composed of the paramagnetic R sub...

The novel phenomena in nanophotonic materials, such as the angle-dependent reflection and negative refraction effect, are closely related to the photonic dispersions E ( p ) . E ( p ) describes the relation between energy E and momentum p of photonic eigenmodes, and essentially determines the optical properties of materials. As E ( p ) is defined in momentum space (k-space), the experimental method to detect the energy distribution, that is the spectrum, in a momentum-resolved manner is highly required. In this review, the momentum-space imaging spectroscopy (MSIS) system is presented, which can directly study the spectral information in momentum space. Using the MSIS system, the photonic dispersion can be captured in one shot with high energy and momentum resolution. From the experimental momentum-resolved spectrum data, other key features of photonic eigenmodes, such as quality factors and polarization states, can also be extracted through the post-processing algorithm based on the coupled mode theory. In addition, the interference configurations of the MSIS system enable the measurement of coherence properties and phase information of nanophotonic materials, which is important for the study of light-matter interaction and beam shaping with nanostructures. The MSIS system can give the comprehensive information of nanophotonic materials, and is greatly useful for the study of novel photonic phenomena and the development of nanophotonic technologies.

Engineering nanoheterostructures (NHs) plays a key role in exploring novel or enhanced physicochemical properties of nanocrystals. Despite previously reported synthetic methodologies, selective synthesis of NHs to achieve the anticipated composition and interface is still challenging. Herein, we presented a colloidal strategy for the regioselective construction of typical Ag-Co2P NHs with precisely controlled location of Ag nanoparticles (NPs) on unique chemically transformed Co2P nanorods (NRs) by simply changing the ratio of different surfactants. As a proof-of-concept study, the constructed heterointerface-dependent hydrogen evolution reaction (HER) catalysis was demonstrated. The multiple Ag NP-tipped Co2P NRs exhibited the best HER performance, due to their more exposed active sites and the synergistic effect at the interfaces. Our results open up new avenues in rational design and fabrication of NHs with delicate control over the spatial distribution and interfaces between different components.

Carbyne is a one-dimensional allotrope of carbon consisting of a linear chain of carbon atoms bonded to each other with exceptional strength. Its outstanding mechanical, optical, and electronic properties have been theoretically predicted, but its stability has only been achieved when grown encapsulated in the hollow core of carbon nanotubes. One of the advantages of this confinement is that its properties can be controlled by the chain's length and surrounding environment. We investigated an alternative way of gaining control of its properties is using isotope labelling as tuning mechanism. The optimized liquid precursor was first chosen among several options, which can greatly enhance the yield of the confined carbyne. Then isotopic labelled liquid precursor was encapsulated for further synthesis of isotopic labelled confined carbyne. This allowed us to obtain pioneering results on isotope engineered carbyne with around 11.9 % of C-13-labelling using C-13-methanol as precursor.

Background The leaf water content estimation model is established by hyperspectral technology, which is crucial and provides technical reference for precision irrigation. Methods In this study, two consecutive years of field experiments (different irrigation times and seven wheat varieties) in 2018–2020 were performed to obtain the canopy spectra reflectance and leaf water content (LWC) data. The characteristic bands related to LWC were extracted from correlation coefficient method (CA) and x-Loading weight method (x-Lw). Five modeling methods, spectral index and four other methods (Partial Least-Squares Regression (PLSR), Random Forest Regression (RFR), Extreme Random Trees (ERT), and K-Nearest Neighbor (KNN)) based characteristic bands, were employed to construct LWC estimation models. Results The results showed that the canopy spectral reflectance increased with the increase of irrigation times, especially in the near-infrared band (750–1350 nm). The prediction accuracy of the newly developed differential spectral index DVI (R1185, R1307) was higher than that of the existing spectral index, with R2 of 0.85 and R2 of 0.78 for the calibration and validation, respectively. Due to a large amount of hyperspectral data, the correlation coefficient method (CA) and x-Loading weight (x-Lw) were used to select the water characteristic bands (100 and 28 characteristic bands, respectively) from the full spectrum. We found that the accuracy of the model based on the characteristic bands was not significantly lower than that of the full spectrum-based models. Among these models, the ERT- x-Lw model performed the best (R2 and RMSE of 0.88 and 1.46; 0.84 and 1.62 for the calibration and validation, respectively). In addition, the accuracy of the LWC estimation model constructed by ERT-x-Lw was higher than that of DVI (R1185, R1307). Conclusion The two models based on ERT-x-Lw and DVI (R1185, R1307) can effectively predict wheat leaf water content. The results provide a technical reference and a basis for crop water monitoring and diagnosis under similar production conditions.

A novel onion-like carbon/Bi12O17Cl2 (OC/Bi12O17Cl2) photocatalysts were prepared via chemical deposition strategy. The surface composition, feature, and optical absorbed capacity of OC/Bi12O17Cl2 materials were characterized via X-ray diffraction (XRD), Raman spectra, X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM), and UV–vis diffuse reflection spectra (UV–vis DRS). It can be found from the characterization and experiment results, OC nanoparticles loaded on the Bi12O17Cl2 surface, forming the heterojunction structure, which increased the separation of photogenerated carriers, exhibiting enhanced optical absorbed capacity. Meanwhile, the band gaps of OC/Bi12O17Cl2 materials decreased in comparison to Bi12O17Cl2 (2.24 vs 2.65 eV). Moreover, in the photocatalytic degradation test of Rhodamine B (RhB) dye, OC/Bi12O17Cl2 samples showed better degradation effect than bare Bi12O17Cl2. The composite material with onion-like carbon loading mass of 3 mg exhibited the best photocatalytic activity and stability in the range of seven cycles. The trapping agent experiments showed that •O2− and h+ were the major active species. Finally, the reasonable mechanism of reaction was speculated.

The concept of “umpolung” reactivity of π-allylmetal complexes has been developed as a powerful method for the allylation of aldehydes. This paper describes the photocatalytic umpolung strategy for...

In this paper, systematic characterization of the dual probe, which is designed for the near field simultaneous measurement of both electric and magnetic field, is investigated with a microstrip line as the device under test (DUT). The characterization includes frequency response, transmission performance, symmetry, reflection, the intrusion of probe to the DUT, isolation of electric and magnetic field responses, field profile and spatial resolution, and differential electric field suppression. The dual probes with different design are adopted to demonstrate the systematic characterization.

The Sm-doping effect on the crystal structure, dielectric and magnetic properties of CeFeO3 ceramics are systemically investigated. A giant dielectric response with high dielectric constant and low dielectric loss at room temperature (RT) is observed in Ce0.5Sm0.5FeO3 compounds. The increase of the dielectric constant is attributed to the increase of the ratio of Fe2+/Fe3+ ionic contents due to the charge transfer between Ce3+ and Fe3+ ions induced by Sm doping. Besides, the starting temperature T1 of spin-reorientation transition from Γ4 (Gx, Ay, Fz) to Γ1 (Ax, Gy, Cz) increases with Sm doping, and even reaches to a higher one than RT. Meanwhile, composite spin configurations of Fe3+ ions containing Γ1 and/or Γ2 (Fx, Cy, Gz) are found at RT in 0.2≤x ≤ 0.5 samples (x is Sm doping level), besides Γ4 state, whose formation originates from the strengthening of the anisotropic exchange interactions between Fe3+ and Ce3+/Sm3+ spins and the coexistence of Ce- and Sm-rich regions caused by Sm doping. It is suggested that the combining and competing functions of the Fe2+-Fe3+ ferromagnetic double-exchange interaction related to the Fe2+ ionic content and the composite spin configurations of Fe3+ ions containing Γ1 and/or Γ2 dominate the dielectric loss of Ce1-xSmxFeO3 ceramics. The results provide a different view for the physical theory and adjustment of the dielectric properties for applications.

Adsorbents based on CuI for π-complexative separation of C2H4/C2H6 have attracted widespread interests. However, they are still confronting some challenges, for example, (i) a low separation efficiency, resulted from the ineffective reduction of CuII to CuI along with aggregation, and (ii) poor stability due to the oxidation of CuI to inactive CuII. In this study, active Cu and auxiliary Co species are simultaneously encapsulated within the nanopores of MIL-101 using a double-solvent (DS) method to obtain CuCoM-DS. The Cu species at the interior of MIL-101 are homogeneously dispersed and can be completely reduced to CuI without any structural damage to MIL-101. The resulting CuCoM-DS exhibits a superior performance in C2H4/C2H6 separation not only to the pristine MIL-101, but to the counterpart samples of single Cu and/or Cu/Co at the exterior of MIL-101. The best sample of 1.5CuCoM-DS adsorbent is capable to adsorb 50.5 mL·g−1 of C2H4, and the C2H4/C2H6 selectivity is 2.6 at 100 kPa. Both C2H4 uptake and C2H4/C2H6 selectivity are higher than those reference samples. Moreover, 1.5CuCoM-DS preserves over 90% of fresh C2H4 uptake after the exposure to atmospheric air for 12 days. This study provides new design ideas for confining bimetallic sites in MOFs for broad applications.

Polarization singularities of vectorial electromagnetic fields locate at the positions (such as points, lines, or surfaces) where properties of polarization ellipses are not defined. They are manifested as circular and linear polarization, for which respectively the semi-major axes and normal vectors of polarization ellipses become indefinite. First observed in conical diffraction in the 1830s, the field of polarization singularities has been systematically reshaped and deepened by many pioneers of wave optics. Together with other exotic phenomena such as non-Hermiticity and topology, polarization singularities have been introduced into the vibrant field of nanophotonics, rendering unprecedented flexibilities for manipulations of light-matter interactions at the nanoscale. Here we review the recent results on the generation and observation of polarization singularities in metaphotonics. We start with the discussion of polarization singularities in the Mie theory, where both electric and magnetic multipoles are explored from perspectives of local and global polarization properties. We then proceed with the discussion of various photonic-crystal structures, for which both near- and far-field patterns manifest diverse polarization singularities characterized by the integer Poincare or more general half-integer Hopf indices (topological charges). Next, we review the most recent studies of conversions from polarization to phase singularities in scalar wave optics, demonstrating how bound states in the continuum can be exploited to generate directly optical vortices of various charges. Throughout our paper, we discuss and highlight several fundamental concepts and demonstrate their close connections and special links to metaphotonics. We believe polarization singularities can provide novel perspectives for light-matter manipulation for both fundamental studies and their practical applications., 17 pages, 7 figures

An integrated process that includes catalytic co-pyrolysis of biomass/plastic wastes and in-line catalytic upgrading of pyrolysis gas were conducted to simultaneously produce aromatics-rich bio-oil and carbon nanotubes (CNTs). The influences of feedstocks blending ratio on the characteristics of bio-oil and CNTs were established. The reaction mechanism of carbon deposition during the system was also probed. The results showed that co-feeding plastic to biomass siginificantly enhanced the selectivity of monoaromatics (benzene, toluene, and xylene) from 5.6% for pure biomass to the maximum yield of 44.4% for 75.0% plastic ratio, and decreased naphthalene and its derivates from 85.9 to 41.7% correspondingly. The most synergistic effect on BTX selectivity occurred at 25% of plastic ratio. The multi-walled CNTs were successfully synethsized on Ni catalyst by utilizing prolysis gas as feedstocks. For pure biomass, the least CNTs yield with ultrafine diameters of 3.9–8.5 nm was generated via disproportionation reaction of CO which was derived from decarboxylation and decarbonylation of oxygenates on the ZSM-5 acid sites. With the rise of plastic ratio, sufficient hydrocarbons were produced for CNTs growth, endowing CNTs with long and straight tube walls, along with uniform diameters (~16 nm). The CNTs yield increased as high as 139 mg/g-cata. In addition, the decreased CO2 inhibited dry reforming with C1-C4 hydrocarbons and deposited carbon, avoiding excessive etching of CNTs. Thereby, high-purity CNTs with less defects were fabricated when plastic ratio was beyond 50% in the feedstock. The strategy is expected to improve the sustainability and economic viability of biomass pyrolysis.

By conducting relative permeability experiments of multi-cycle gas-water displacement and imbibition on natural cores, we discuss relative permeability hysteresis effect in underground gas storage during multi-cycle injection and production. A correction method for relative permeability hysteresis in numerical simulation of water-invaded gas storage has been worked out using the Carlson and Killough models. A geologic model of water-invaded sandstone gas storage with medium-low permeability is built to investigate the impacts of relative permeability hysteresis on fluid distribution and production performance during multi-cycle injection and production of the gas storage. The study shows that relative permeability hysteresis effect occurs during high-speed injection and production in gas storage converted from water-invaded gas reservoir, and leads to increase of gas-water transition zone width and thickness, shrinkage of the area of high-efficiency gas storage, and decrease of the peak value variation of pore volume containing gas, and then reduces the storage capacity, working gas volume, and high-efficiency operation span of the gas storage. Numerical simulations exhibit large prediction errors of performance indexes if this hysteresis effect is not considered. Killough and Carlson methods can be used to correct the relative permeability hysteresis effect in water-invaded underground gas storage to improve the prediction accuracy. The Killough method has better adaptability to the example model.

As one of the most important imaging modalities, magnetic resonance imaging (MRI) still faces relatively low sensitivity to monitor low-abundance molecules. A newly developed technology, hyperpolarized 129Xe magnetic resonance imaging (MRI), can boost the signal sensitivity to over 10 000-fold compared with that under conventional MRI conditions, and this technique is referred to as ultrasensitive MRI. However, there are few methods to visualize complex mixtures in this field due to the difficulty in achieving favorable “cages” to capture the signal source, namely, 129Xe atoms. Here, we proposed metal–organic frameworks (MOFs) as tunable nanoporous hosts to provide suitable cavities for xenon. Due to the widely dispersed spectroscopic signals, 129Xe in different MOFs was easily visualized by assigning each chemical shift to a specific color. The results illustrated that the pore size determined the exchange rate, and the geometric structure and elemental composition influenced the local charge experienced by xenon. We confirmed that a complex mixture was first differentiated by specific colors in ultrasensitive MRI. The introduction of MOFs helps to overcome long-standing obstacles in ultrasensitive, multiplexed MRI., Metal organic frameworks with tunable pore structures are able to provide varied chemical environments for hyperpolarized 129Xe atom hosting, which results in distinguishing magnetic resonance signals, and stains ultra-sensitive magnetic resonance imaging (MRI) with diverse colors.

Rensch's rule is an allometric rule on sexual size dimorphism. It states that in small-sized species, females are larger than males, whereas in larger species, males are relatively larger than females. Several studies have explored this pattern, and its inverse in lizard species. China has a unique and high diversity of species, with a variety of ecological systems which shape diversity of phenotypes. In this study, sexual size dimorphism and Rensch’s rule were determined using a dataset of Chinese lizard species. The findings show that Chinese lizards generally exhibit female-biased sexual size dimorphism. In addition, clutch size was positively correlated with sexual size dimorphism. Agamidae species were the only taxa that followed Rensch’s rule (slope of males against females was steeper than 1). Clutch size was correlated with sexual size dimorphism in groups that do not follow Rensch's rule. This finding implies that strong fecundity selection limits application of Rensch's rule in these groups.

Although the use of sophisticated fluorescent probes can improve the detection sensitivity, either the lack of quantitative design for fluorophores or the deficiency of selectivity towards individual species makes it extremely difficult to distinguish homologs accurately. Herein, this study reports a quantitative strategy for the systematic engineering of fluorophores via density functional theory (DFT). A series of seven 1,8-naphthylamide hydrazine (NH-1–7) compounds was elaborately tailored on the basis of the PET mechanism, EPS charge population and the maximum HOMO overlap principle. The results showed that the obtained NH-4 exhibited 300-fold “off–on” signal towards carbonyls with extraordinary reactivity and high solubility. Importantly, the ultra-low limits of detection (LOD) towards multi-carbonyl homologs could reach 1.0 × 10−12 M on the ultra-high pressure liquid chromatography (UHPLC) in an 8 min analysis window. This systematic and quantitative engineering of fluorophores lays a bridge between efficient development of novel fluorophores and trace level detection in various matrixes.

A robust and sustainable C(sp2)–C(sp3) cross-electrophile coupling was developed via nickel/copper synergistic catalysis under micellar conditions. This protocol provided a general method to access alkylated arenes with good to excellent yields on a very large scale.

The major functions of the subsea Christmas tree include production management, wellhead pressure control, chemical reagent injection, and oil/gas production safety control. It is necessary to investigate the reliability and safety of the tree for safe and stable operation of subsea production systems. A fault tree and a dynamic Bayesian model are used to assess reliability and safety and to consider the time slice-based characteristics of the reliability. Using the control variable method, impact analysis is performed to quantify the impact of each failure rate on the system and sort the impacts of failure modes on reliability and safety. Finally, failure prediction is performed. The results show that the annulus loop has the lowest reliability and is the most likely to fail. The failure rate of the tubing hanger has the biggest impact on system reliability, while the failure rate of the choke valve has the biggest impact on system safety. When the tree fails, the failure probabilities of the tubing hanger and the valve group of the production loop are relatively high. On the basis of the above results, corresponding control measures are proposed that can significantly reduce the failure risk of the tree.

Proton-conducting nanofiber hybrid membranes (PC-NFHMs) as promising candidates, are widely used for proton exchange membrane fuel cells (PEMFCs), combining the properties and some synergism from interactions between nanofibers and the polymer matrix. The PC-NFHMs possess superior characteristics compared to individual ion-conducting polymeric membranes or free-standing electrolyte inorganic films. Herein, this critical review presents the progress of PC-NFHMs, with specific focus on the combinations of multifunctional nanofibers and emerging proton transfer carriers, such as metal organic frameworks (MOFs), porous organic cages (POCs), polyhedral oligomeric silsesquioxanes (POSSs), amino acids (AAs), etc. The unique properties and performance of the different types of multifunctional nanofibers and their derivatives are described with respect to their use as PC-NFHMs. Besides, relevant characterization studies including small angle X-ray scattering (SAXS), nuclear magnetic resonance (1H-NMR), and molecular dynamics calculation (MDC), have been briefly summarized to understand proton-conducting mechanisms (Vehicle and Grotthuss mechanisms) in electrolyte membranes. These systematic discussions and proposed directions can trigger thoughts and provide ways to reasonably design PC-NFHMs for PEMFCs in the near future.

We disclose a transition-metal-free decarbonylative alkylation reaction for the synthesis of N-aryl α-hydroxy amides via precise cleavages and reorganizations of three C–C σ bonds. For the first time, a medium-sized cycloalkyl was used as a leaving group to initiate the decarbonylative alkylation process. We also demonstrate the concept of “one-pot” inert C–C bond activation/deuteration. This strategy allows the formation of α,β-deuterated hydroxyamides by using DMSO-d6 as a solvent.

Proton conduction is a ubiquitous fundamental phenomenon in biological systems. Biology has solved the problem of energy-related proton conduction, in which the exposed amino acids in the protein ordered channels play a key role in proton conduction. In this contribution, amino acids (glutamate, lysine, and threonine) were attached to metal organic framework (MOF) nanoparticles, which were incorporated into sulfonated polysulfone matrix forming bio-proton channels for the nanocomposite membranes. It is shown in the results that the amino acid-functionalized MOF can help to enhance the proton conductivity and the proton exchange membrane with glutamate-functionalized MOF demonstrate excellent proton conductivity of 0.212 S cm−1 at 80 °C and 100% relative humidity. Meanwhile, the methanol permeability coefficient of the nanocomposite membrane is reduced to 5.8 × 10−7 cm2 s−1. The nanocomposite membranes demonstrate excellent proton conductivity, dimensional stabilities, water absorption, and resistance to methanol performance. Therefore, this material is promising for fuel cells.

Effective solutions to the two primary dilemmas of inadequate energy supply and environmental contamination have become a significant focus of researchers for the sustainable development of society and the ecological system. Transforming ubiquitous mechanical force and temperature variation energies into chemical energy by means of the intrinsic characteristics of piezoelectric and pyroelectric nanomaterials is widely considered to be a powerful strategy to counteract the environmental and energy crisis owing to prominent advantages such as the efficient utilization of directional electric charges and enormous source of stress and temperature fluctuation. This review summarizes the advances in energy and environmental catalysis driven by stress and temperature variation based on piezoelectric and pyroelectric effects. Firstly, the internal characteristics of charge carrier separation and transportation of piezoelectric/pyroelectric catalysts in response to external stress and temperature oscillations and the rational mechanisms of piezoelectric/pyroelectric catalysis are elucidated. Then, the catalytic production of renewable fuels (H2 evolution from water splitting and CO2 reduction) and environment remediation (decomposition of organic dyes, mineralization of antibiotics, bacterial inactivation, and removal of heavy metal ions) based on a large number of piezocatalytic and pyrocatalytic catalysts with diverse modification strategies are thoroughly summarized. Finally, the existing challenges and future prospects in this emerging territory are proposed. This comprehensive review is anticipated to offer a powerful reference for the profound research and applications of piezoelectric and pyroelectric materials in the fields of the environment and energy by utilizing ubiquitous mechanical and temperature fluctuation energies.

The laminar–turbulence transition phenomenon widely exists on the surface of many energy equipment, which is deserved to be studied because of the complex mechanics and some induced undesirable consequences. The goal of present work is to investigate the transitional flows around the forward and reversed hydrofoils at different incidences using the SST γ - R e ˜ θ t transition model, with special emphasis on the dynamics of the transition. The effect of inflow turbulence condition is considered initially. Then, the difference between the original SST k- ω model and SST γ - R e ˜ θ t transition model is analyzed, in terms of the near-wall velocity profiles and flow morphology. Afterwards, the change of the transition with the incidence for the reversed hydrofoil is clarified in detail. The primary results show that the flow separation near the sharp leading edge where the reverse dynamic vortex (RDV) appears makes the contribution to the transition. The size of RDV is much larger than laminar separation bubble (LSB) over the forward hydrofoil and it forms near the leading edge earlier. Moreover, the transition locations are mapped both for the forward and reversed hydrofoils. Finally, the effect of Reynolds number on the transition process for the reversed hydrofoil is presented. It is believed that this work can deep the understandings of the transition, especially for the reversed hydrofoils.

Rechargeable aprotic alkali metal (Li and Na)–iodine (AM–I2) batteries with high theoretical capacity and specific energy density have emerged as one of the promising energy storage technologies. However, their application has been severely limited by dendrite formation on alkali metal anodes. By infusing a eutectic Li–Na alloy into a carbon cloth (CC), we developed a novel bifunctional Li–Na alloy-CC anode for Li/Na–iodine batteries with significantly enhanced electrochemical performance. Specifically, the LiNa-CC anode in a symmetric battery exhibited an ultra-stable cycling stability up to 800 and 1650 hours for Li and Na plating/stripping at a current density of 40 and 20 mA cm−2, respectively. When coupled with an iodine cathode in a Li/Na–iodine battery, the LiNa-CC anode exhibited a significantly improved cycling stability with 84.8% and 83.3% capacity retentions after 2000 cycles at a current density of 5C for Li–I2 and Na–I2 batteries, respectively. This work provides new perspectives for developing multifunctional dendrite-free alkali metal–iodine batteries.

Sulfide-based solid-state electrolytes (SSEs) matched with alloy anodes are considered as promising candidates for application in all-solid-state batteries (ASSBs) to overcome the bottlenecks of the lithium (Li) anode. However, an understanding of the dynamic electrochemical processes on alloy anode in SSE is still elusive. Herein, in situ atomic force microscopy gives insights into the block-formation and stack-accumulation behaviors of Li precipitation on an Li electrode, uncovering the morphological evolution of nanoscale Li deposition/dissolution in ASSBs. Furthermore, two-dimensional Li-indium (In) alloy lamellae and the homogeneous solid electrolyte interphase (SEI) shell on the In electrode reveal the precipitation mechanism microscopically regulated by the alloy anode. The flexible and wrinkle-structure SEI shell further enables the electrode protection and inner Li accommodation upon cycles, elucidating the functional influences of SEI shell on the cycling behaviors. Such on-site tracking of the morphological evolution and dynamic mechanism provide an in-depth understanding and thus benefit the optimizations of alloy-based ASSBs.