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The Co center is active in electrochemical CO2 reduction (CO2RR), and its activity can be tuned by changing its coordination environment. However, the coordination number around the Co center cannot be readily changed in homogeneous systems owing to bimolecular decomposition of reduced low-coordinate Co species. Herein we report the systematic tuning of N atom numbers from 2 to 5 in the first coordination sphere around Co centers supported on two-dimensional metal-organic layers (MOLs) for the electrochemical CO2RR. The N atoms come from a combination of bipyridine, terpyridine, and phenylpyridine ligands. The Co centers are isolated and stabilized on the MOL to prevent bimolecular decomposition. All of the catalysts, denoted MOL-Co-Nx (x = 2-5), are active in reducing CO2 to CO electrochemically, but their activities are highly dependent on the number of coordinating N atoms. MOL-Co-N3 showed the highest current density of 2.3 A mg-1 with a CO Faradaic efficiency of 99% at an overpotential of only 380 mV. Density functional theory calculations attribute the high activity of the Co-N3 center to a balance of ligand field strength and open coordination site: the high ligand field strength promotes back-bonding, while the open coordination site allows HCO3- assistance, both of which accelerate C-O cleavage. MOLs thus provide a unique platform to systematically study the relationship between the coordination environment and the reactivity of open metal sites in electrocatalysis.

The influence of rock mechanical properties on the electromagnetic radiation (EMR) mechanism of rock fracturing is an important research topic in solid mechanics and earthquake prediction. In this study, an EMR model of rock fracturing considering the fracture factor, elastic modulus, Poisson’s ratio, radiation distance and crack length is derived based on the Hertz oscillator array assumption. An experimental system, including an electromagnetic shielding module, an EMR signal induction and transmission module, a signal recording module and a loading module, is developed to understand the EMR characteristics of four different rocks. The validity of the EMR theoretical model is verified and the relationships between the rock cracking morphology and the EMR waveform, amplitude and frequency are revealed. It is found that rock mechanical properties have obvious influences on the EMR waveform, amplitude and frequency during rock fracturing. This study provides a better understanding on the EMR mechanism of rock fracturing and can help to improve the accuracy of rock disaster prediction based on EMR.

Molecular catalysts for H2-evolution are of interest for their integration into light-harvesting complexes for photocatalytic water splitting. Here, we report the meso-tetra (4-carboxyphenyl) porphine [(TCPP)PtII] complex as a molecular H2-evolving photocatalyst using chloranilic acid (CA) as a sacrificial electron donor, the choice of which is critical to the stability of the photocatalyst. When triethanolamine was used, [(TCPP)PtII] decomposed to form Pt nanoparticles. Density functional theory calculations together with evidence from electrochemical and spectroscopic analyses suggested that the catalysis was possibly initiated by a proton-coupled electron transfer (PCET) to form [(TCPP)PtI]-N-H, followed by another electron injection and protonation to form a [(TCPP)PtII-hydride]-N-H intermediate that can release H2. As the whole catalytic cycle involves the injection of multiple electrons, a light-harvesting network should be helpful by providing multiple photo-induced electrons. Thus, we integrated this molecular catalyst into a light-harvesting metal-organic framework to boost its activity by ~830 times. This work presents a mechanistic study of the photocatalytic H2 evolution and energy transfer and highlights the importance of a light-harvesting network for multiple electron injections.

Semantic segmentation of 3D Light Detection and Ranging (LiDAR) indoor point clouds using deep learning has been an active topic in recent years. However, most deep neural networks on point clouds conduct multi-level feature fusion via a simple U-shape architecture, which lacks enough capacity on both classification and localization in the segmentation task. In this paper, we propose a Neural Architecture Search (NAS) method to search a Feature Pyramid Network (FPN) module for 3D indoor point cloud semantic segmentation. Specifically, we aim to automatically find an effective feature pyramid architecture as a feature fusion neck in a designed novel pyramidal search space covering all information communication paths for multi-level features. The searched FPN module, named SFPN, contains the most important connections among all the potential paths to fuse representations at different levels. Our proposed SFPN is generic and effective as well as capable to be added to existing segmentation networks to augment the segmentation performance. Extensive experiments on ScanNet and S3DIS show that consistent and remarkable gains of segmentation performance can be achieved by different classical networks combined with SFPN. Specially, PointNet++-SFPN achieves mIoU gains of 7.8% on ScanNet v2 and 4.7% on S3DIS, and PointConv-SFPN achieves 4.5% and 3.7% improvement respectively on the above datasets.

In this paper we propose and analyze a finite difference numerical scheme for the Poisson-Nernst-Planck equation (PNP) system. To understand the energy structure of the PNP model, we make use of the Energetic Variational Approach (EnVarA), so that the PNP system could be reformulated as a non-constant mobility H − 1 H^{-1} gradient flow, with singular logarithmic energy potentials involved. To ensure the unique solvability and energy stability, the mobility function is explicitly treated, while both the logarithmic and the electric potential diffusion terms are treated implicitly, due to the convex nature of these two energy functional parts. The positivity-preserving property for both concentrations, n n and p p , is established at a theoretical level. This is based on the subtle fact that the singular nature of the logarithmic term around the value of 0 0 prevents the numerical solution reaching the singular value, so that the numerical scheme is always well-defined. In addition, an optimal rate convergence analysis is provided in this work, in which many highly non-standard estimates have to be involved, due to the nonlinear parabolic coefficients. The higher order asymptotic expansion (up to third order temporal accuracy and fourth order spatial accuracy), the rough error estimate (to establish the ℓ ∞ \ell ^\infty bound for n n and p p ), and the refined error estimate have to be carried out to accomplish such a convergence result. In our knowledge, this work will be the first to combine the following three theoretical properties for a numerical scheme for the PNP system: (i) unique solvability and positivity, (ii) energy stability, and (iii) optimal rate convergence. A few numerical results are also presented in this article, which demonstrates the robustness of the proposed numerical scheme.

Mechanical stability and multicycle durability are essential for emerging solid sorbents to maintain an efficient CO2 adsorption capacity and reduce cost. In this work, a strong foam-like composite is developed as a CO2 sorbent by the in situ growth of thermally stable and microporous metal-organic frameworks (MOFs) in a mesoporous cellulose template derived from balsa wood, which is delignified by using sodium chlorite and further functionalized by 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation. The surface carboxyl groups in the TEMPO-oxidized wood template (TO-wood) facilitate the coordination of the cellulose network with multivalent metal ions and thus enable the nucleation and in situ growth of MOFs including copper benzene-1,3,5-tricarboxylate [Cu3(BTC)2], zinc 2-methylimidazolate, and aluminum benzene-1,3,5-tricarboxylate. The TO-wood/Cu3(BTC)2 composite shows a high specific surface area of 471 m2 g–1 and a high CO2 adsorption capacity of 1.46 mmol g–1 at 25 °C and atmospheric pressure. It also demonstrates high durability during the temperature swing cyclic CO2 adsorption/desorption test. In addition, the TO-wood/Cu3(BTC)2 composite is lightweight but exceptionally strong with a specific elastic modulus of 3034 kN m kg–1 and a specific yield strength of 68 kN m kg–1 under the compression test. The strong and durable TO-wood/MOF composites can potentially be used as a solid sorbent for CO2 capture, and their application can possibly be extended to environmental remediation, gas separation and purification, insulation, and catalysis.

This study is to develop a method for isolation, identification, and quantitative determination of dammarane-type triterpene saponins in the Panax notoginseng fruits (PNF). The saponins were isolated by a serious of chromatographic methods, and their structures were elucidated on the basis of spectroscopic evidence and comparison with those of literature reports. Quantitative assay was performed on an ultra-performance liquid chromatography-UV (UPLC-UV) method. As a result, 22 saponins were isolated from the extract of PNF, among them, compound 1 was a new saponin, named as malonylgypenoside IX, compounds 3-10, and 14-18 were isolated from the PNF for the first time. As to quantitative analysis, the calibration curves showed good linearity (r > 0.998) within the concentration range, and the method validation provided good reproducibility and sensitivity for the quantification of eight major saponins with precision and accuracy of less than 3.0%.

Atomically dispersed oxide-on-metal inverse nanocatalysts provide a blueprint to amplify the strong oxide-metal interactions for heterocatalysis but remain a grand challenge in fabrication. Here we report a 2D inverse nanocatalyst, RuOx -on-Pd nanosheets, by in situ creating atomically dispersed RuOx /Pd interfaces densely on ultrathin Pd nanosheets via a one-pot synthesis. The product displays unexpected performance toward the oxygen reduction reaction (ORR) in alkaline medium, which represents 8.0- and 22.4-fold enhancement in mass activity compared to the state-of-the-art Pt/C and Pd/C catalysts, respectively, showcasing an excellent Pt-alternative cathode electrocatalyst for fuel cells and metal-air batteries. Density functional theory calculations validate that the RuOx /Pd interface can accumulate partial charge from the 2D Pd host and subtly change the adsorption configuration of O2 to facilitate the O-O bond cleavage. Meanwhile, the d-band center of Pd nanosubstrates is effectively downshifted, realizing weakened oxygen binding strength.

ZrZnOx is active in catalyzing carbon dioxide (CO2) hydrogenation to methanol (MeOH) via a synergy between ZnOx and ZrOx. Here we report the construction of Zn2+-O-Zr4+ sites in a metal-organic framework (MOF) to reveal insights into the structural requirement for MeOH production. The Zn2+-O-Zr4+ sites are obtained by postsynthetic treatment of Zr6(μ3-O)4(μ3-OH)4 nodes of MOF-808 by ZnEt2 and a mild thermal treatment to remove capping ligands and afford exposed metal sites for catalysis. The resultant MOF-808-Zn catalyst exhibits >99% MeOH selectivity in CO2 hydrogenation at 250 °C and a high space-time yield of up to 190.7 mgMeOH gZn-1 h-1. The catalytic activity is stable for at least 100 h. X-ray absorption spectroscopy (XAS) analyses indicate the presence of Zn2+-O-Zr4+ centers instead of ZnmOn clusters. Temperature-programmed desorption (TPD) of hydrogen and H/D exchange tests show the activation of H2 by Zn2+ centers. Open Zr4+ sites are also critical, as Zn2+ centers supported on Zr-based nodes of other MOFs without open Zr4+ sites fail to produce MeOH. TPD of CO2 reveals the importance of bicarbonate decomposition under reaction conditions in generating open Zr4+ sites for CO2 activation. The well-defined local structures of metal-oxo nodes in MOFs provide a unique opportunity to elucidate structural details of bifunctional catalytic centers.

Two-photon polymerization additive manufacturing has great demand for new and efficient two-photon initiators. Acetylene bridged A-π-D-π-A initiator molecules based on phenothiazine and carbazole were designed and synthesized via Sonogashira coupling reaction utilizing benzophenone and fluorenone as electron-donating groups. The ultraviolet-visible absorption spectra, fluorescence emission spectra, two-photon absorption cross section, two-photon fluorescence properties, as well as their photoinitiation properties as initiators, were studied. The results showed that different electron donors and acceptors directly affect the photophysical properties of molecules, and their effects are interrelated. Among them, under the action of femtosecond laser, the two-photon absorption cross section of the molecule with phenothiazine as the donor and benzophenone as the acceptor can reach 327 GM at 780 nm. Two-photon polymerization experiments have also proved that it can indeed initiate trimethylolpropane triacrylate photopolymerization for micro-/nano-manufacturing. The scanning rate reached 2000 μm s−1 at a laser power of 30 mW during the polymerization process, and the complete and clear three-dimensional structures were obtained. The highest resolution of the complete three-dimensional structure was about 280 nm.

This paper investigates the benefits of distributed hybrid power systems employing multiple fuel-cell vehicles. In earlier work, our optimization of hybrid power systems showed that a single fuel cell acting as backup power to guarantee energy sustainability operates for less than 3% of the time but incurs more than 16% of the system costs. Therefore, the system cost could be reduced when applying a fuel-cell vehicle to dynamically support twelve power stations. Here, we extend this idea by employing multiple fuel-cell vehicles to support more power stations. We develop a power management strategy and optimize the management parameters by the genetic algorithm. The results show a reduction of more than 21% by applying multiple fuel-cell vehicles in the distributed systems. Experiments also confirm the feasibility of using multiple fuel-cell vehicles. Based on the results, the proposed systems are deemed effective for reducing system costs while maintaining system sustainability.

Modifying the electronic structure and optimizing the geometric structure can expeditiously tune the electrocatalytic properties of catalysts, resulting in considerably enhanced electrocatalytic performance towards electrocatalytic oxidation of liquid fuels. We herein report a simple synthetic strategy to prepare Bi-doped 3D taraxacum-like Pd nanocages (NCs) composed of porous nanosheets, which possess high surface areas and strong synergistic effects. Notably, a trace of Bi diffuses into the lattice of Pd and increases the electronic effects of the surface of Pd, endowing PdBi-0.5 NCs/C with superior electrocatalytic performance towards ethanol oxidation reaction (EOR). The mass activity and specific activity of PdBi-0.5 NCs/C were 3494.8 mA mgPd−1 and 10.37 mA cm−2, being 4.08- and 4.82- fold enhancements as compared with commercial Pd/C, respectively. Moreover, the highly open porous 3D nanocages structure with rich active sites and defects can also facilitate the mass/electron transfer to favor the EOR kinetics.

The reaction of a metallo-organic ligand (LA) in which two “V”-shaped bisterpyridines attaching to meta-position of “X”-shaped tetraterpyridine via connectivity and Zn2+ ions gave rise to 3D supramolecular architectures: octagram (Zn8LA4). However, a position varied ligand (LB) in which two “V”-shaped bisterpyridines locating at the ortho-position of “X”-shaped tetraterpyridine afforded a different 3D hexagram (Zn6LB3). Full characterizations included NMR (1H, 13C, 2D COSY, NOESY and DOSY), ESI-MS, TWIM-MS, TEM and AFM. The resulted structures were directly determined by the position of two “V”-shaped bisterpyridines attaching to “X”-shaped tetraterpyridine.

Two new prenylated flavanonols, named as fortunones A (1) and B (2), and one new geranylated flavanone, named as fortunones C (3), were isolated from the fruits of Paulownia fortunei (Seem.) Hemsl. Their structures were elucidated distinctly according to their UV, MS, NMR, and CD spectra. Structural modifications on prenyl and geranyl groups in these isolated compounds were uncommon for Paulownia flavanones. Only compounds 1 and 3 showed weak antioxidant effect on human umbilical vein endothelial cells injury induced by H2O2.

Water resources are the foundation of economic development, social progress and ecological security, and water shortage is the primary problem facing China. Water quotas have great practical significance for the resolution of water shortages to achieve sustainable use of water resources and sustainable development of the national economy. In this study, to analyse the problems and countermeasures of the water quota system in China, the water quota system progress domestically and abroad, the water quota problem in China, and the countermeasures for the water quota problem are summarized. The data validity test, spatial correlation test and consistency test are used to test the rationality of water use quota. And the specific countermeasures are presented: improving the water quota system, defining its concept, and revising its scheme, etc. This study provides the support to standardize water quotas and implement the effective water conservation policies of China. HIGHLIGHTS Introduces a method that uses data validity test, spatial correlation test and consistency test of the water quota reasonableness to test the rationality of water quota.; Presents several specific recommendations: improving the water quota system, defining its concept and revising its scheme; Provides the support to standardize water quotas and implement the effective water conservation policies.

In geological history, volcanism is closely related to the deposition of many black shales. However, the specific mechanism between volcanism and the deposition of black shales is still unclear. The black shales developed in the Chang 7 Member of the Yanchang Formation in the Ordos Basin are considered the most important hydrocarbon source rocks in Central China. The shales are deposited by frequent volcanic activities and preserved by extremely rich volcanic ash layers, making them an excellent example when investigating the influence of volcanism on the deposition of black shales. In this paper, petrographic, mineralogical, and geochemical analyses of three typical tuff and black shale segments of the Chang 7 Member were carried out. The productivity indicators [total organic carbon (TOC), P/Al, Ni/Al, and Cu/Al], redox indicators (V/Al, Mo/Al, U/Al and U/Th), and clastic influx indicators (Ti/Al and ƩREE) of the shales basically increased together in the longitudinal direction, and a relatively good positive correlation existed between P/Al, Ni/Al, Cu/Al, V/Al, Mo/Al, U/Al, U/Th, Ti/Al, ƩREE, and TOC. This finding indicated that the development of the Chang 7 black shales is the result of a combination of high primary productivity, anoxic conditions, and increased clastic influx. Considering that increased clastic influx may dilute organic matter, many phosphate nodules represented high productivity above the volcanic ash layers, and anoxic conditions are likely to be the result of a large amount of organic matter degradation indicated by the covariations of TOC versus P/Al and TOC versus Ba/Al. Therefore, the Chang 7 black shales in this study may be mainly controlled by the increased primary productivity. In addition, compared with the Weathering Index of Parker of background shales (not the contact clip or tuff layer), that of the black shales was significantly reduced after tuff deposition. On the contrary, the clastic influx indicators, redox indicators, productivity indicators of black shales significantly increased. This finding suggested that a series of environmental effects, such as enhanced weathering of terrestrial sources, increased clastic influx, anoxic water, and productivity bloom, was likely caused by volcanic activity. Considering that hydrothermal activity at the same time as volcanism may not cause productivity bloom, the nutrients (P/Al and Fe/Al) of the Chang 7 tuffs were significantly depleted, and the total sulfur content of black shales was much higher than that in ordinary freshwater sedimentation. Therefore, this paper reviewed and proposed the volcanism hypothesis model of the Chang 7 black shales. Volcanism generates large amounts of SO2 and volcanic ash. SO2 forms large areas of acid rain and accelerates terrigenous weathering with an increase in the lake land-based sources of debris and nutrient supply, while volcanic ash is decomposed and releases nutrients. These phenomena lead to biological productivity bloom and massive accumulation of organic matter, which in turn results in lake water anoxia and the eventual formation of black shales.

Alkali-water electrolyzers and hydroxide exchange membrane fuel cells are emerging as promising technologies to realize hydrogen economy. Developing cost-effective electrode materials with high activities towards corresponding hydrogen evolution (HER) and oxidation (HOR) reactions plays a crucial role in commercial hydrogen production and utilization. Herein, we fabricated a V-doped Ni3N/Ni heterostructure (V-Ni3N/Ni) through a controlled nitridation treatment on a V-incorporated nickel hydroxide precursor. The resultant catalyst exhibits comparable catalytic activity and durability to commercial Pt/C in terms of both HER (a low overpotential of 44 mV at the current density of 10 mA·cm−2) and HOR (a high current density of 1.54 mA·cm−2 at 0.1 V versus reversible hydrogen electrode) under alkaline conditions. The superior activity of V-Ni3N/Ni grown on different substrates further implies its intrinsic performance. Density functional theory (DFT) calculations reveal that the coupled metallic Ni and doped V can promote the water adsorption, accelerate the Volmer step of alkaline HER, as well as optimize the adsorption and desorption of hydrogen intermediate (H*) to reach a balanced ΔGH* value.

The restoration of the coastal environment can help to alleviate declining offshore fishery resources. When artificial fish reefs utilizing steelmaking slag are deployed on the seabed, they can improve algal growth to create habitats for fisheries enhancement. However, the use of slag reefs in the marine environment in Taiwan may draw public concerns about the compatibility of placing steel by-products in the marine environment and food safety issues. It is therefore likely that the further use of slag reefs for marine productivity enhancement (MPE) may encounter resistance and face uncertainty. In this study, controversial issues related to the application of slag reefs to the development of subsequent marine ranching were explored. Qualitative interviews with stakeholders were conducted, and their support or opposition for the application of steelmaking slag to the marine environment were discussed. The results of the interviews were analyzed based on grounded theory to establish conceptual models and clarify stakeholders’ policy opinions on the marine application of slag reefs. The results can inform policy for the further utilization and management of slag reefs, and may help the government to promote the circular economy and achieve its ultimate goal of sustainable ocean development.

Aromatic thermoset materials have shown great potential applications in various fields owing to their excellent mechanical strengths. However, their poor ductility is still hinders their large-scale applications. In this study, a new class of aromatic thermosets consisting of two types of crosslinks was successfully developed by incorporating the special group imidazole into a type of crosslinked thermoset. One crosslink is constituted of reversible multiple noncovalent interactions containing “face-face” π–π stacking, “point-point” hydrogen bonds, and ion-pair electrostatic interactions, whereas the other is composed of permanent covalent bonds. Most importantly, the synergetic interplay among these reversible multiple noncovalent interactions enables them to evade the restrictions from the aromatic polymer skeletons to proceed with their dynamic dissociating-rebuilding processes, which can timely and effectively dissipate the internal stress. Finally, owing to the coefficient of these two types of crosslinks, a significantly enhanced ductility was successfully obtained on these aromatic thermosets and their tensile strengths were also improved. Such thermosets having simultaneously enhanced strengths and ductility are predicted to be eventually used in a wide range of applications.

Magnetic digital microfluidics is advantageous over other existing droplet manipulation methods, which exploits magnetic forces for actuation and offers the flexibility of implementation in resource-limited point-of-care applications. This article discusses the dynamic behavior of a pair of sessile droplets on a hydrophobic surface under the presence of a permanent magnetic field. A phase field method-based solver is employed in a two-dimensional computational domain to numerically capture the dynamic evolution of the droplet interfaces, which again simultaneously solves the magnetic and flow fields. On a superhydrophobic surface (i.e., θc = 150°), the nonuniform magnetic field forces the pair of sessile droplets to move toward each other, which eventually leads to a jumping off phenomenon of the merged droplet from the solid surface after coalescence. Also, there exists a critical magnetic Bond number Bomcr, beyond which no coalescence event between droplets is observed. Moreover, on a less hydrophobic surface (θc ≤ 120°), the droplets still coalesce under a magnetic field, although the merged droplet does not experience any upward flight after coalescence. Also, the merging phenomenon at lower contact angle values (i.e., θc = 90°) appears significantly different than at higher contact angle values (i.e., θc = 120°). Additionally, if the pair of sessile droplets is dispersed to a different surrounding medium, the viscosity ratio plays a significant role in the upward flight of the merged droplet, where the coalesced droplet exhibits increased vertical migration at higher viscosity ratios.

Whether or not the topology of three-dimensional covalent organic frameworks (3D COFs) can be tuned via steric control remains a big question and has never been reported. Herein, we describe the designed synthesis of two highly crystalline 3D COFs (3D-TPB-COF-OMe and 3D-TPB-COF-Ph), through the polycondensation of tetra(p-aminophenyl)methane and methoxy- or phenyl- substituted 1,2,4,5-tetrakis(4-formylphenyl)benzene on the 3- and 6-positions. Amazingly, by using the continuous rotation electron diffraction technique, 3D-TPB-COF-OMe is determined to have a 5-fold interpenetrated structure with a reported pts net, while 3D-TPB-COF-Ph adopts an unprecedented self-penetrated ljh topology (ljh = Luojia Hill) that does not exist in the database of ToposPro. Therefore, by altering the substituents from methoxy to phenyl groups, the topology of designed 3D COFs changes accordingly, and a rare net is now available. This result clearly demonstrates that such COF structures need to be carefully determined due to its complexity, and moreover, it is promising to design 3D COFs with new topology for interesting application by increasing the steric hindrance of molecular building blocks.

The extensive use of diesel heavy duty trucks (diesel HDTs) has led to substantial atmospheric pollutant and greenhouse gas (GHG) emissions in Beijing-Tianjin-Hebei-Shandong (BTHS) region, China. The substitution of hydrogen fuel cell heavy duty trucks (HFC-HDTs) for their diesel counterparts is effective to solve the problems above. Aiming at the BTHS region, a GPERF (GHG emission, Pollutant emission and Economic cost Reduction in Fuel cycle) assessment model was established combining with regional vehicle data to investigate the reductions of GHG emissions, pollutant emissions and economic expenditures by the substitution scheme. Data indicated that population of diesel HDTs and HFC-vehicles in BTHS region both accounted for reaching 25% of total in country. Results showed that the fuel substitution scheme could significantly reduce the GHG and pollutant emissions by vehicles in BTHS region, among which the GHG reduced by 1/3, while the NOx and PM remarkably reduced by around 50%.

Metal chalcogenide supertetrahedral Tn clusters are of current interest for their unique compositions and structures, which rely highly on the structure-directing agents. Herein, we report four novel Tn cluster-based indium and gallium sulfides, namely, [NH(CH3)3]4In4S10H4 (1), (NH3)4Ga4S6 (2), [NH3CH2CH3]5(NH2CH2CH3)2Ga11S19 (3), and [NH3CH2CH2OH]6Ga10S18·2NH2CH2CH2OH (4). All four compounds were solvothermally synthesized in mixed amine-ethanol solutions or deep eutectic solvent (DES), where ammonia/amine molecules play significant structure-directing roles in the speciation and crystal growth. (1) Being protonated, the trimethylamine and ethanolamine molecules surround the T2-[In4S10H4]4- clusters (for 1) and [Ga10S18]n6n- open framework (for 4), respectively, compensating for the negative charge of the inorganic moieties. (2) With the lone pair of electrons, the ammonia molecules in 2 coordinate directly to corner Ga3+ ions of the {Ga4S6} cage to give a neutral T2-(NH3)4Ga4S6 cluster. (3) For compound 3, part of the ethylamine molecules act as terminating ligands for the T1 and T3 units in the [Ga11S19(NH2CH2CH3)2]n5n- layer, while the rest act as interlamellar countercations upon protonation. Theoretical studies reveal the contributions of N, C, and H to the density of states (DOS) for 2 and 3 because of their hybrid structures that combine the ammonia/amine ligands with sulfide moieties together.

Deuterium excess (d-excess), as a secondary parameter of water stable isotopes, inherits the meteorological information from moisture source to the site of interest. Understanding the climatic implications of d-excess in ice cores from the Tibetan Plateau (TP) is critical for reconstructing the paleoclimate. Here we present an annually-dated ice core record retrieved from the central TP and analyze the correlations between the ice core d-excess record and local and regional climate variables in the past decades (1948–2011). Our results show poor correlations between d-excess and local meteorological parameters, deemphasizing the local control on the interannual variations in d-excess records. However, significant correlations exist between the d-excess record and the relative humidity over the eastern Arabian Sea and Bay of Bengal. In addition, our results indicate that d-excess is positively correlated with temperature in the Nino 3.4 region, demonstrating that large-scale atmospheric circulation through ENSO cycle affecting the interannual d-excess signal in ice cores from the central TP. Mechanically speaking, in annual scale, the higher (lower) temperature that occurs in the eastern tropical Pacific Ocean in El Nino (La Nina) years is accompanied by the ascending branch of the Walker circulation weakening (enhancing) in the Indian Ocean region, leading to lower (higher) relative humidity value in the moisture source regions of the Arabian Sea and Bay of Bengal, and subsequently producing higher (lower) d-excess value in the central Tibetan ice core records. This finding will enhance the understanding of the climatic significance of ice core d-excess in the Asian monsoon region.

Photoelectrocatalytic nanomaterials are promising for direct alcohol fuel cells, but the construction of high-efficiency catalysts remains difficult. We herein successfully synthesized three-dimensional (3D) PdM nanosheet assemblies (PdM NSAs, M = Au, Ag, and Cu) through a seed-mediated growth method, which displayed a typical 3D nanoflower morphology assembled from many two-dimensional ultrathin nanosheets. Due to the open 3D structure and the synergistic and electronic effects between Pd and Ag, the optimized PdAg NSAs showed the highest mass activity (9378 mA mg

The interaction between graphite particles and argon plasma in the arc torch is investigated by numerical simulations. The addition of carbon vapor improves the specific heat capacity, electrical conductivity and thermal conductivity of plasma, and decreases its viscosity. It is important to note that the changes in the thermodynamic and transport properties of the plasma substantially affect the arc plasma temperature and the spatial distribution of the carbon vapor concentration. As the graphite particle feed rate increases, the arc will be continuously contracted and the arc electric current density will be increased. The carbon vapor enhances the plasma electrical conductivity, but the heat absorption by the particles reduces the temperature of the plasma, eventually leading to decreased the electrical conductivity. Both result in ascent of the electric field of the arc, so that increase the arc voltage. In addition, the heat flux radial distribution of radiation-absorption of the particles is much less than the thermal conduction, but the particles near the wall absorb radiation from arc region, so that reduce energy loss of the radiation of the arc column.

The effects of nozzle structures and working pressure on the dynamic characteristics of supersonic turbulent free jets have been investigated numerically. Four types of nozzles (namely Laval, pipe, contraction I, and contraction II, respectively) and four pressure conditions (namely K = 0.8, 1, 1.5, and 2, respectively) were considered. A Standard k-ε model was utilized for the calculation of the supersonic turbulent free jets. Validation of the model was performed on the Laval jet by comparing it with the experiment and large-eddy simulation (LES). A perfect agreement was achieved in terms of the centerline and radial axial velocity profiles. The jets issuing from the Laval and the pipe had a longer potential core and a larger centerline axial velocity with the same outlet momentum. The length of the potential core was proportional to the working pressure, but variations of the centerline axial velocity decay rate were inverse for all nozzles. The effects of nozzle structures and work pressure on the spreading rates of the jets were insignificant. No obvious change trend could be observed on the kinematic and geometric virtual origins. The study can provide references for the nozzle and working pressure selection in practical application.

The effects of Cl−, Cu2+ and Fe3+ ions and their combinations on the corrosion behaviour of aluminium alloy 6063 (AA6063) in ethylene glycol and water solutions at 50 °C were investigated by electrochemical and immersion methods. Cl− resulted in pitting corrosion of the alloy. In the Cl−-free solutions, Fe3+ was prone to accelerate uniform corrosion, while Cu2+ tended to accelerate pitting corrosion. Severe pitting corrosion of AA6063 was observed in the cases of Cl− combined with Cu2+ or Fe3+, especially in the case of Cl− combined with Cu2+ and Fe3+ ions.

Stress-sensitive permeability (SSP) influences gas well productivity and is a crucial element influencing gas reservoir development. SSP for high-pressure fractured gas reservoirs with an initial reservoir pressure of more than 20 MPa has never been comprehensively evaluated to the best of our knowledge. SSP experiments with special procedures were designed by adopting the variable confining pressure (VCP) and variable internal pressure (VIP) methods. VCP is a test method in which the confining pressure is altered and a constant internal pressure is maintained for the experimental core holder. VIP is a test method in which the internal pressure is changed and a constant confining pressure is maintained. A four-stage curve analysis method was developed to perform regressions on semilogarithmic curves and exponential curves of experimental data. A method to evaluate the SSP was developed using stress sensitivity coefficients obtained via regressions. A calculation approach for determining the degrees of permeability damage and permeability recovery also was evaluated. In total, six matrix cores and six cores with artificial fractures from a high-pressure fractured sandstone gas reservoir were tested using the two methods. The SSP curves for high-pressure reservoirs were characterized by four-stage variation trends, which show differentiation with low-pressure reservoirs with an initial reservoir pressure less than 20 MPa. The stress sensitivity of the VCP method was stronger than that of the VIP method. The core samples mainly showed a “medium”/“medium-strong” stress sensitivity under low/high effective stress conditions. Compared with matrix cores, fractured cores showed stronger stress sensitivity owing to strong plasticity and weak elasticity. The maximum permeability damage degree reached 99.67%, and the minimum permeability recovery was only 6.9%. Our method of experimental design, four-stage curve analysis, stress sensitivity evaluation, and our overall findings can provide references for future studies on SSP in high-pressure fractured sandstone gas reservoirs.

A concise total synthesis of (+)-aphanorphine is described. The key features of the strategy include a Pd-catalyzed intermolecular trimethylenemethane [3+2]-cycloaddition to form ring C and a Co-catalyzed radical cyclization through a hydrogen-atom transfer to close ring B. The synthesis was completed in six steps.

Analysis of the intermolecular vibrational modes in a fingerprint region is always difficult. It is particularly hard to figure out the normal modes, especially in the far-infrared (IR) region, whi...

As a dynamic and essential component in the road environment of urban scenarios, vehicles are the most popular investigation targets. To monitor their behavior and extract their geometric characteristics, an accurate and instant measurement of vehicles plays a vital role in traffic and transportation fields. Point clouds acquired from the mobile laser scanning (MLS) system deliver 3D information of road scenes with unprecedented detail. They have proven to be an adequate data source in the fields of intelligent transportation and autonomous driving, especially for extracting vehicles. However, acquired 3D point clouds of vehicles from MLS systems are inevitably incomplete due to object occlusion or self-occlusion. To tackle this problem, we proposed a neural network to synthesize complete, dense, and uniform point clouds for vehicles from MLS data, named Vehicle Points Completion-Net (VPC-Net). In this network, we introduce a new encoder module to extract global features from the input instance, consisting of a spatial transformer network and point feature enhancement layer. Moreover, a new refiner module is also presented to preserve the vehicle details from inputs and refine the complete outputs with fine-grained information. Given sparse and partial point clouds as inputs, the network can generate complete and realistic vehicle structures and keep the fine-grained details from the partial inputs. We evaluated the proposed VPC-Net in different experiments using synthetic and real-scan datasets and applied the results to 3D vehicle monitoring tasks. Quantitative and qualitative experiments demonstrate the promising performance of the proposed VPC-Net and show state-of-the-art results., accepted by ISPRS Journal of Photogrammetry and Remote Sensing

This paper presents the growth law of electrical tree in glass/epoxy resin composite (GER). Two influencing factors on electrical tree growth, the relative permittivity of the glass and the adhesion type of the interface, are investigated. An improved WZ model is built to further explore the mechanism of electrical tree growth in GER. The electric field between the needle electrode and the glass is enhanced when the relative permittivity of glass is higher than that of epoxy resin, which is responsible for the attractive effect of the glass. The breakdown strength of the interface determines the growth mode of electrical tree. When the breakdown strength of the interface is as low as the air gap, the electrical tree showed ‘linear growth’ at the interface. High breakdown strength of the interface lead to ‘step growth’ of electrical tree and prolong the growth time compared to ‘linear growth’.

To quickly isolate suspected cases to control the epidemics, this study proposes a body temperature monitoring system with a thermography based on the Internet of Things (IoT) architecture. The collected data are transmitted to a back-end platform via wireless communication. Using the analyzed data, the platform provides services, such as instant alerts for any anomalies, infectious disease outbreak prediction, and risk level assessment for a given area, and it will be a great help to epidemic prevention. The mean absolute percentage error and root mean square error of the proposed monitoring system under an extensive series of experiments are 0.04% and 0.0204°C, respectively. It shows that the body temperature measured by the thermal imaging sensor in the system can accurately represent the actual body temperature after specific calibrations that take the environmental temperature into account. It can also be expanded to a decision supporting system to help schools or government agencies to make proper decisions to stop the spread of infectious diseases.

Sodiumion batteries(SIBs) have attracted intensive attention as promising alternative to lithium-ionbatteries(LIBs) for large scale energy storage systems because of low cost of sodium, similar energy storage mechanism and the reasonable performance. However, it is still a great challenge to search and design a robust structure of anode materials with excellent cycling stability and high rate capability for SIBs. Herein, multilayer porous vanadium nitride (VN) microsheets are synthesized through a facile and scalable hydrothermal synthesis-nitrogenization strategy as an effective anode material for SIBs. The multilayer porous VN microsheets not only offer more active sites for fast Na+ insertion/extraction process and short diffusion pathway, but also effectively buffer the volume change of anode due to more space in the multilayer porous structure. The large proportions of capacitive behavior imply that the Na+ charge storage depends on the intercalation pseudocapacitive mechanism. The multilayer porous VN microsheets electrodes manifest excellent cycling stability and rate capability, delivering a discharge capacity of 156.1 mA·h/g at 200 mA/g after 100 cycles, and a discharge capacity of 111.9 mA·h/g at 1.0 A/g even after 2300 cycles with the Coulombic efficiency of nearly 100%.

The ongoing COVID-19 epidemic worldwide necessitates the development of novel effective agents against SARS-CoV-2. ACE2 is the main receptor of SARS-CoV-2 S1 protein and mediates viral entry into host cells. Herein, the membrane nanoparticles prepared from ACE2-rich cells are discovered with potent capacity to block SARS-CoV-2 infection. The membrane of human embryonic kidney-239T cell highly expressing ACE2 is screened to prepare nanoparticles. The nanomaterial termed HEK-293T-hACE2 NPs contains 265.1 ng mg−1of ACE2 on the surface and acts as a bait to trap SARS-CoV-2 S1 in a dose-dependent manner, resulting in reduced recruitment of the viral ligand to host cells. Interestingly, SARS-CoV-2 S1 can translocate to the cytoplasm and affect the cell metabolism, which is also inhibited by HEK-293T-hACE2 NPs. Further studies reveal that HEK-293T-hACE2 NPs can efficiently suppress SARS-CoV-2 S pseudovirions entry into human proximal tubular cells and block viral infection with a low half maximal inhibitory concentration. Additionally, this biocompatible membrane nanomaterial is sufficient to block the adherence of SARS-CoV-2 D614G-S1 mutant to sensitive cells. Our study demonstrates a easy-to-acheive memrbane nano-antagonist for curbing SARS-CoV-2, which enriches the existing antiviral arsenal and provides new possibilities to treat COVID-19.Graphical Table of Contents

The phenomenon of micro-cracks on the sheds is due to aging of the composite insulator. With the development of the Unmanned Aerial Vehicle (UAV) technology, the online aging characterization based on micro-cracks turns out to be a reality. In this article, the micro-cracks identification and characterization on the sheds of composite insulators based on visible spectrum image was studied. At first, the shed area was segmented after graying and binarization operation. Then, the Laplace of Gaussian (LoG) operator and Otsu algorithm were used to extract the texture of micro-cracks. Box-counting method was used to calculate the fractal dimension of the micro-cracks on the composite insulator shed. The index of fractal dimension, a number between 1 and 2, can be used to describe the roughness and density of fractal dimension. The higher the fractal dimension was, the more severe the micro-cracks would be. The experimental results proved that the method proposed was feasible and effective on micro-cracks identification and characterization.

Flame propagation in Hele-Shaw cells with a micro-sized gap was experimentally investigated. The evolution of flame front morphology was recorded via Schlieren photographs as the hydrogen-oxygen (H2–O2) mixture was ignited at ambient temperature and pressure. By varying gap size, two different regimes of flame propagation are identified: 1) the non-accelerating flame in narrow gaps; 2) the self-accelerating flame in relatively wide gaps. For the former, the initial flame front is globally circular, and subsequently evolves into branches separated from the surface, exhibiting dendritic-growth and fingering shapes. In the latter regimes, the flame front exhibits a cellular structure and accelerates nearly sonic speed due to hydrodynamic instabilities. It is found that the flame acceleration depends non-monotonically on the gap size due to the competing mechanisms of viscosity friction and heat loss through the walls. The effect of equivalence ratio on the non-accelerating flame is studied to identify the mechanism controlling the local extinction flame.

The localized surface plasmon resonance of plasmonic nanoparticles (NPs) can be coupled with a noble metal substrate (S) to induce a localized augmented electric field (E-field) concentrated at the NP-S gap. Herein, we analyzed the fundamental near-field properties of metal NPs on diverse substrates numerically (using the 3D finite-difference time-domain method) and experimentally [using surface-enhanced Raman scattering (SERS)]. We systematically examined the effects of plasmonic NPs on noble metals (Ag and Au), non-noble metals (Al, Ti, Cu, Fe, and Ni), semiconductors (Si and Ge), and dielectrics (TiO2, ZnO, and SiO2) as substrates. For the AgNPs, the Al (11,664 times) and Si (3969 times) substrates produced considerable E-field enhancements, with Al in particular generating a tremendous E-field enhancement comparable in intensity to that induced by a Ag (28,224 times) substrate. Notably, we found that a superior metallic character of the substrate gave rise to easier induction of image charges within the metal substrate, resulting in a greater E-field at the NP-S gap; on the other hand, the larger the permittivity of the nonmetal substrate, the greater the ability of the substrate to store an image charge distribution, resulting in stronger coupling to the charges of localized surface plasmon resonance oscillation on the metal NP. Furthermore, we measured the SERS spectra of rhodamine 6G (a commonly used Raman spectral probe), histamine (a biogenic amine used as a food freshness indicator), creatinine (a kidney health indicator), and tert-butylbenzene [an extreme ultraviolet (EUV) lithography contaminant] on AgNP-immobilized Al and Si substrates to demonstrate the wide range of potential applications. Finally, the NP-S gap hotspots appear to be widely applicable as an ultrasensitive SERS platform (∼single-molecule level), especially when used as a powerful analytical tool for the detection of residual contaminants on versatile substrates.

Reducing the warranty cost to increase profit is a major focus for most businesses. To achieve this goal, the acceptance sampling plan (ASP) can be an efficient tool to validate whether the product...

A novel covalent organic framework material COF-DM, which contains chelating coordination environments, was synthesized at the gram level under mild conditions. In addition, its Cu(II)-loaded complex of Cu(II)@COF-DM was prepared by impregnating COF-DM in an acetonitrile solution of CuCl2 via a solid-state coordination approach. The obtained Cu(II)-loaded Cu(II)@COF-DM can be used as a highly active heterogeneous catalyst to catalyze the alkyne-dihalomethane-amine coupling reactions.

Metal–organic frameworks (MOFs) have been studied extensively in the hydrogen evolution reaction (HER) and the water oxidation reaction (WOR) with sacrificial reagents, but overall photocatalytic water splitting using MOFs has remained challenging, principally because of the fast recombination of photo-generated electrons and holes. Here we have integrated HER- and WOR-MOF nanosheets into liposomal structures for separation of the generated charges. The HER-MOF nanosheets comprise light-harvesting Zn–porphyrin and catalytic Pt–porphyrin moieties, and are functionalized with hydrophobic groups to facilitate their incorporation into the hydrophobic lipid bilayer of the liposome. The WOR-MOF flakes consist of [Ru(2,2′-bipyridine)3]2+-based photosensitizers and Ir–bipyridine catalytic centres, and are localized in the hydrophilic interior of the liposome. This liposome–MOF assembly achieves overall photocatalytic water splitting with an apparent quantum yield of (1.5 ± 1)% as a result of ultrafast electron transport from the antennae (Zn–porphyrin and [Ru(2,2′-bipyridine)3]2+) to the reaction centres (Pt–porphyrin and Ir–bipyridine) in the MOFs and efficient charge separation in the lipid bilayers. Some metal–organic frameworks (MOFs) can promote photocatalytic hydrogen evolution and others can facilitate water oxidation, but it is difficult to combine them into a single system. Now, by confining MOFs that can promote each half-reaction within the hydrophobic and hydrophilic regions of a liposome to avoid the fast recombination of photo-generated charges, evidence for water splitting has been obtained.

Two-photon absorption (TPA) of many chromophores can be enhanced by building them into the structure of metal–organic frameworks (MOFs). However, light scattering of MOFs defocuses the light beam a...

Carnitine is an essential metabolite that is absorbed from the diet and synthesized in the kidney, liver, and brain. It ferries fatty acids across the mitochondrial membrane to undergo β-oxidation. Carnitine has been studied as a therapy or protective agent for many neurological diseases and neurotoxicity (e.g., prolonged anesthetic exposure-induced developmental neurotoxicity in preclinical models). Preclinical and clinical data support the notion that carnitine or acetyl carnitine may improve a patient's quality of life through increased mitochondrial respiration, release of neurotransmitters, and global gene expression changes, showing the potential of carnitine beyond its approved use to treat primary and secondary carnitine deficiency. In this review, we summarize the beneficial effects of carnitine or acetyl carnitine on the central nervous system, highlighting protective effects against neurotoxicity-induced damage caused by various chemicals and encouraging a thorough evaluation of carnitine use as a therapy for patients suffering from neurotoxicant exposure.

The fixed-loop transient electromagnetic method (TEM) is used to detect the distribution of goafs in a proposed thermal power plant in the northern part of Shaanxi Province, China. A basic geoelectric model of the goaf was established using borehole data, a pore-skeletal model, and a parallel resistance model. The Arjuna module of the Maxwell software was used to perform 2.5-dimensional forward modeling in order to make the model more realistic, and then the conventional software IX1D was used to perform one-dimensional inversion of the forward results. The model results show that the low-resistivity anomaly composed of the water-filled goaf and the fissures in its roof and floor forms an obvious anomalous response on the resistivity contour section. This abnormal feature can be used as the basis for the interpretation of the goaf. When there are no cracks in the roof or floor and only water-filled goafs, it is difficult to identify low-resistivity anomalies. The processed data collected on site show that the fixed-loop TEM has a clear image of the shallow strata geoelectric structure. The coal-bearing seam is the stable and continuous high-resistivity target layer. According to the results of the fixed-loop TEM, the range of the goaf, the range of the coal-bearing strata with the pores filled by argillaceous materials, and the range of the coal-free strata with the pores filled by calcareous materials are respectively delineated. The TEM results agreed well with the available borehole data. The TEM detection results are reliable and replace the need for extensive drilling.

Oxygen reduction reaction (ORR) catalyst is one of the most significant influential factors for the application of proton exchange membrane fuel cells. This work introduces a mass-producible high-performance PtZn alloy integrative structure ORR catalyst, synthesized with the atomically dispersive metal-organic framework precursors. This PtZn catalyst displays excellent catalytic activity with the onset reduction potential of 1.0 VRHE@ 0.16 mA cm−2 (Reversible hydrogen electrode; RHE) and the half-wave potential of 0.934 VRHE for the ORR catalysis. The calculated specific activity and mass activity at 0.9 V are 9.44 A m−2 and 544 A gPt−1, respectively, which are 5.62 times and 5.77 times as high as the commercial Pt/C. The mass activity is remarkably higher than the target put forward by the Department of Energy (DOE; 440 A gPt−1). Furthermore, this PtZn catalyst also exhibits outstanding stability after the 10,000 potential cyclic degeneration test. The ORR current is much higher than Pt/C in the whole potential range not only before but also after the 10,000 potential cycles with identical Pt loading. This catalyst has a multifarious active-site catalytic structure with PtZn alloyed particles and atomically dispersive metal-N active sites on the N-doped graphited carbon matrix, exhibiting appealing ORR catalytic activity and sound stability for the application and scalable production of fuel cell catalysts.

The development of high-performance and cost-effective electrocatalysts towards oxygen reduction reaction (ORR) is of significant importance, but still challenging for the practical applications in related energy systems. ORR process typically suffers from sluggish kinetics, the exploration of ORR electrocatalyst thus requires elaborate design. Herein, an effective strategy is developed for growing Co/N-doped carbon nanotube arrays on 2D MOFs-derived matrix via the pyrolysis of Co/Zn metal-organic-framework (MOF) nanosheets. The Co/Zn-MOF nanosheets serve as both the self-template for the 2D carbonized framework morphology and C/N source for the in-situ growth of 1D N-doped carbon nanotubes. The constructed hierarchical architecture effectively integrates the 0D/1D Co nanoparticle/N-doped carbon nanotube interface and 1D (nanotubes)/2D (nanosheets) junction into frameworks with highly exposed active surface, enhanced mass-transport kinetics and electrical conductivity. As a result, the designed composite exhibits superior ORR activity and durability in alkaline media as compared to commercial Pt/C. Particularly, it shows promising ORR performance with a half-wave potential of 0.78 V versus reversible hydrogen electrode and negligible activity attenuation after 5000 potential cycles in acidic electrolyte. The designed strategy can be extended to construct other MOFs-derived carbon matrixes with diverse hierarchical structures and provide an efficient avenue for searching high-performance electrocatalysts.

LiDAR-based localization in a city-scale map is a fundamental question in autonomous driving research. As a reasonable localization scheme, the localization can be performed by global retrieval (that suggests potential candidates from the database) followed by geometric registration (that obtains an accurate relative pose). In this work, we develop a novel end-to-end, deep multi-task network that simultaneously performs global retrieval and geometric registration for LiDAR-based localization. Both retrieval and registration are formulated and solved as regression problems, and they can be deployed independently during inference time. We also design two mechanisms to enhance our multi-task regression network’s performance: residual connections for point clouds and a new loss function with learnable parameters. To alleviate the common phenomenon of vanishing gradients in neural networks, we employ residual connections to support constructing a deeper network effectively. At the same time, to solve the problem of huge differences in scale and units between different tasks, we propose a loss function that can automatically balance multi-tasks. Experiments on two public benchmarks validate the state-of-the-art performance of our algorithm in large-scale LiDAR-based localization.

Development of the more stable nonprecious oxygen reduction reaction (ORR) catalyst is of great significance nowadays. Herein, a high-performance iron-doped integral uniform macrocyclic organic framework (MOF–FeZn) catalyst is synthesized through a combined hydrothermal and pyrolysis process, showing favorable ORR activity and stability in acid. This as-synthesized MOF–FeZn catalyst displays high porous and graphitic structures with sufficient catalytic active dopants of pyridinic N, Fe–N, pyrrolic N, graphitic N, making it a promising ORR candidate catalyst with high electrochemical stability. The onset potential, half-wave potential and limited diffusion current density of MOF–FeZn are 0.93 V @ 0.1 mA cm−2, 0.768 V@ 2.757 mA cm−2 and 5.5 mA cm−2, respectively, which are comparable to the state-of-the-art nonprecious catalyst and commercial Pt/C. ORR catalysis on MOF–FeZn follows the nearly four-electron path. What is more, MOF–FeZn can sustain the 10,000 cycles electrochemical potential cycling process in acid with the half-wave potential changed only 21 mV, superior to the reduction of 149 mV for Pt/C. The well-developed integral uniform structures, homogeneously dispersed carbides and nitrides protected by the highly graphitic carbon layers and the better agglomeration suppression of nanoparticles by the confined graphitic carbon layers on catalyst can significantly enhance the catalytic activity and stability of MOF–FeZn.

The International GNSS Service (IGS) has been providing reliable Global Ionospheric Maps (GIMs) since 1998. The Ionosphere Associate Analysis Centers (IAACs) model the global ionospheric Total Electron Content (TEC) and generate the daily GIM products within the context of the IGS. However, the rapid and final daily GIM products have a latency of at least one day and one week or so, respectively. This limits the value of GIM products in real-time GNSS applications. We propose and develop an approach for near real-time modeling of global ionospheric TEC by using the hourly IGS data. We perform an experiment in a real operating environment to generate near real-time GIM (named BUHG) products for more than two years. Final daily GIM products, Precise Point Positioning (PPP) based VTEC resources, and JASON-3 Vertical TEC (VTEC) measurements are collected for testing the performance of BUHG. The results show that the performance of BUHG is very close to that of the daily GIM products. Also, there is good agreement between BUHG and PPP-derived VTEC as well as with JASON-3 VTEC. It is possible that BUHG would be further improved with an increase in available hourly GNSS data.