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X-ray diffraction analysis with synchrotron radiation and scanning electron microscopy are used to perform a complex study of the structural and phase states of a hydrogenated palladium-based membrane alloy. Fluctuations of the phase composition of alloy are considered after the introduction of hydrogen into the metallic system. Areas of the hydride (β) phase and diluted hydrogen solid solution (α phase) are found in the alloy. The processes that take place in the crystal lattice in the course of the β ↔ α transformation are determined. The development of defects and changes in the root-mean square displacements of alloy atoms, which result from the reaction of a material with occluded hydrogen, are analyzed. [ABSTRACT FROM AUTHOR]

A precise X-ray diffractometry method is employed to investigate a Pd-In-Ru alloy foil subjected to electrolytic hydrogenation. It is revealed that an increase in the scattering volume of the sample and its multiphase disintegration are caused by the α → β transformation. The basic characteristics of the given transformation are established. [ABSTRACT FROM AUTHOR]

A series of ruthenium [NNN]- or [NCN]-type complexes (3–7) bearing PPh3 ancillary ligands have been synthesized from pyridine- or phenylene-bridged bis(triazoles) 1 and 2. In the case of [NNN]-pincer complex 3, an unusual and unexpected cis-orientation adopted by two sterically demanding PPh3 ligands was observed, and such configuration proved to be unchanged in solution for a long time. By contrast and as expected, the two phosphines are found to be trans to each other in the case of [NCN]-type pincer complex 4, but an oxidation of RuII center to RuIII occurred. Complex cis-3 underwent ligand exchanges leading to the formations of diphosphine derivatives 5 and 6. As a representative, cis-3 was treated with the base in isopropanol affording a mixture of Ru–hydrido complexes with various phosphine binding modes, one of which (trans-7) bearing two trans-standing phosphines has been successfully isolated and fully characterized. The catalytic performances of all newly synthesized Ru complexes have been examined and compared in transfer hydrogenations of ketones and enones, in which mono-phosphine complexes proved to be significantly superior to their diphosphine counterparts. The catalytic process proved to involve Ru–H key intermediates, but the trans-oriented Ru–H species is unlikely to be the main catalytic contributor. In particular, the best performer cis-3 exhibits high chemoselectivity in certain cases catalyzing α,β-unsaturated ketones, whose behavior is quite different compared to most precedents. [ABSTRACT FROM AUTHOR]

The sluggish reaction kinetics of alkaline hydrogen oxidation reaction (HOR) is one of the key challenges for anion exchange membrane fuel cells (AEMFCs). To achieve robust alkaline HOR with minimized cost, we developed a single atom-cluster multiscale structure with isolated Pt single atoms anchored on Ru nanoclusters supported on nitrogen-doped carbon nanosheets (Pt1-Ru/NC). The well-defined structure not only provides multiple sites with varied affinity with the intermediates but also enables simultaneous modulation of different sites via interfacial interaction. In addition to weakening Ru–H bond strength, the isolated Pt sites are heavily involved in hydrogen adsorption and synergistically accelerate the Volmer step with the help of Ru sites. Furthermore, this catalyst configuration inhibits the excessive occupancy of oxygen-containing species on Ru sites and facilitates the HOR at elevated potentials. The Pt1-Ru/NC catalyst exhibits superior alkaline HOR performance with extremely high activity and excellent CO-tolerance. An AEMFC with a 0.1 mg·cmPGM−2 loading of Pt1-Ru/NC anode catalyst achieves a peak powder density of 1172 mW·cm−2, which is 2.17 and 1.55 times higher than that of Pt/C and PtRu/C, respectively. This work provides a new catalyst concept to address the sluggish kinetics of electrocatalytic reactions containing multiple intermediates and elemental steps. [ABSTRACT FROM AUTHOR]

Base, especially KOH, can be used in place of xantphos for the Ruthenium-complex-catalyzed C-O bond cleavage of β-O-4 lignin model compounds. In the presence of KOH, RuHCl(CO)(PPh) and Ru(H)(CO)(PPh) show the best catalytic effect among several ruthenium-complexes studied. Graphical Abstract: Base, especially KOH, can be used in place of xantphos for the Ruthenium-complex-catalyzed C-O bond cleavage of β-O-4 lignin model compounds. In the presence of KOH, RuHCl(CO)(PPh) and Ru(H)(CO)(PPh) show the best catalytic effect among several ruthenium-complexes studied.[Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Graphitic carbon nitrides were employed to prepare the Ruthenium-based ammonia synthesis catalysts by thermal decomposition of Ru(CO) under N or H atmosphere. Different pretreatment atmospheres significantly affected the interaction between Ru nanoparticles and the graphitic carbon nitride. The strong metal support interaction enhanced the electronic density transfer from rich-electron π-plane of the support to the Ru nanoparticles. And it further caused the upshift of d-band center of Ru nanoparticles. The upshift of d-band center improved the ability of surface to bond to N, and consequently the ammonia synthesis activity was enhanced. Graphical Abstract: Electron-rich and graphitic carbon nitride enhanced the electron density of Ru nanoparticles. And that caused the upshift of d-band center of Ru nanoparticles. This upshift of d-band center improved the ability of surface to bond to N, and consequently the ammonia synthesis activity was enhanced. [ABSTRACT FROM AUTHOR]

We prove a generalized Picone-type identity for the Finsler p-Laplacian and use it to establish qualitative results for some boundary-value problems involving the Finsler p-Laplacian. [ABSTRACT FROM AUTHOR]

New tridentate 2,6-bis(imino)pyridyl ruthenium(II) complexes, [N]Ru(H)(Cl)(2,4,6-(CH)CHNH) ( 4) and [N]Ru(Cl)2(2,4,6-(CH)CHNH) ( 5) ([N] = 2,6-(2,4,6-(CH)CHN=CCH)CHN) have been synthesized and characterized. The crystal of complex 4, which has been grown in benzene/cyclohexane by evaporation at room temperature, was studied by X-ray diffraction. Complex 4 crystallizes in the monoclinic space group C2/ c with cell parameters of a = 42.243(4) Å, b = 8.1480(5) Å, c = 23.662(2) Å, β = 117.998(1)°, V = 7191.1(10)Å, and Z = 8. The molecular structure of 4 shows a six coordinate, pseudo-octahedral geometry with a trans arrangement of hydrogen and chloride ligands. The mesityl ligands are oriented approximately perpendicular to the 2,6-bis(imino)pyridyl ligand plane, and form a pocket surrounding the 2,4,6-trimethyl benzenamine ligand. The coordinated 2,4,6-trimethyl benzenamine (2,4,6-(CH)CHNH) is in the cis to chloride and hydride, trans to pyridine ligand, and lies parallel to one of the mesityl rings. [ABSTRACT FROM AUTHOR]

(η5-Dp)Ru(PPh3)2H (Dp = C8H9−, 1,2-dihydropentalenyl) was synthesized in 90% yield by reaction of (η5-Dp)Ru(PPh3)2Cl with sodium formate. (η5-Dp)Ru(PPh3)2H was characterized by 1H and 31P NMR spectroscopy and IR spectroscopy. The Ru–H appears in the 1H NMR spectrum upfield at −11.6 ppm, indicative of a metal hydride. In the IR spectrum, the νRu–H was observed at 1920 cm−1. The solid-state structure of (η5-Dp)Ru(PPh3)2H (1) was determined by X-ray crystallography. Compound 1 has similar structural parameters to (η5-Cp)Ru(PPh3)2H and (η5-Ind)Ru(PPh3)2H. [ABSTRACT FROM AUTHOR]

Four carbonyl hydrido RuII complexes with different functionalized α,α'-diimine ligands have been synthesized and well characterized by IR, UV/vis, CV, ESI/MS, and 1H NMR spectra. One of the complexes was also characterized by X-ray crystallography. The luminescence of these complexes has been investigated at room temperature in CH2Cl2 solution and low temperature glassy media at 77 K. The emissions are originated from either ligand-centered π–π* transitions or metal center to ligand charge transfer (MLCT), which are highly dependent on the properties of the α-diimine ligands. [ABSTRACT FROM AUTHOR]

Fractal dimension has been considered as a measure of fracture surface roughness of materials. Three-dimensional (3D) surface analysis is anticipated to provide a better evaluation of fracture surface toughness and fractal dimension. The objective of this study was to quantify the fracture surfaces and identify a potential relationship between fracture toughness and fractal dimension in a new type of core-shell titanium-iron particulate reinforced hydroxyapatite matrix composites using SEM stereoscopy coupled with a 3D surface analysis. The obtained results showed that both fracture surface roughness and fractal dimension increased with increasing amount of core-shell Ti-Fe reinforcing particles. The fractal dimension was observed to be a direct measure of fracture surface roughness. The fracture toughness of the composites increased linearly with the square root of fractal dimensional increment (i.e., followed the Mecholsky-Mackin equation well) due to the presence of Ti-Fe particles along with the effect of porosity in brittle materials. The 3D fractal analysis was suggested to be a proper tool for quantifying the fracture surfaces and linking the microstructural parameter to fracture toughness. [ABSTRACT FROM AUTHOR]

Heat capacities of the carbon nanotubes (CNTs) with different sizes have been measured by modulated temperature differential scanning calorimetry (MDSC) and reported for the first time. The results indicated the values of C increased with shortening length of CNTs when the diameters of CNTs were between 60 and 100 nm. However, the values of C of CNTs were not affected by their diameter when the lengths of CNTs were 1-2 um, or not affected by the length of CNTs when their diameters were below 10 nm. The thermal stabilities of the CNTs have been studied by TG-DTG-DSC. The results of TG-DTG showed that thermal stabilities of CNTs were enhanced with their diameters increase. With lengths increase, the thermal stabilities of CNTs increased when their diameters were between 60 and 100 nm, but there is a slight decrease when their diameters were less than 60 nm. The further DSC analyses showed both released heat and T increased with the increase of CNTs diameters, which confirms the consistency of the results from both TG-DTG and DSC on CNTs thermal stability. [ABSTRACT FROM AUTHOR]

Selective methanation of CO in the reformate gas (CO/CO2/H2/H2O = 0.175/17.9/70.9/11.1) proceeded over Ru catalysts supported on metal oxides and zeolites. CO was selectively methanated at wide temperature ranges (200–275 °C) over Ru/γ-Al2O3, Ru/TiO2 Ru/H-Y and Ru/H-beta catalysts. Higher Ru contents in Ru/γ-Al2O3 improved the selective CO methanation rate. [ABSTRACT FROM AUTHOR]

The in situ reaction equation of B4C and TiO2 was identified using thermodynamic calculations and XRD analysis. The optimum presintering process was determined according to investigating the effect of presintering temperature on the flexural strength and porosity of the porous B4C–TiB2 preform. The effect of in situ synthesized TiB2 on the reaction products and initial reaction temperature of B4C and Al was discussed based on DSC and XRD analysis. The results showed that the in situ synthesized TiB2 could effectively improve the mechanical properties of the B4C–TiB2–Al composite, elevate the initial reaction temperature of B4C and Al, change the reaction products, and moderate the reaction of B4C and Al. The mechanism of reaction between B4C and Al was discussed. [ABSTRACT FROM AUTHOR]

An efficient system for in vitro regeneration of red leaf beet, a variety of leaf beet ( Beta vulgaris L. var cicla L.) generally used to decorate parterre and to prepare betacyanin, was developed for the first time in the present study. Shoot tip and petiole explants from the sterile seedlings, precultured on Murashige and Skoog (MS) medium with 15 mg/l 6-benzyladenine (BA) and 3% sucrose at 16 °C for 30 days, could form 81.02 and 17.33% translucent nodular (TN) calli, respectively. All TN calli were able to differentiate into adventitious shoots under the same culture conditions. Each explant with TN callus from the shoot tip and petiole could generate 8.65 shoots on average. It was found that both preculture of sterile seedlings and culture of explants at low temperature (16 °C) were vital for TN callus induction and adventitious bud formation of red leaf beet. The best condition for rooting was 0.5-strength MS medium with 10 g/l sucrose. After being transplanted into soil, plantlets grew well and could flower and bear fruits. Histological observation revealed that TN callus was derived from the cells of vascular tissue of the petiole and that adventitious shoots were formed through organogenesis. The factors influencing in vitro micropropagation are also discussed. [ABSTRACT FROM AUTHOR]

A facile approach for the heterogenization of transition metal catalysts using non-covalent interactions in hollow click-based porous organic polymers (H-CPPs) is presented. A catalytically active cationic species, [Ru(bpy)] (bpy = 2,2'-bipyridyl), was immobilized in H-CPPs via electrostatic interactions. The intrinsic properties of [Ru(bpy)] were well retained. The resulting Rucontaining hollow polymers exhibited excellent catalytic activity, enhanced stability, and good recyclability when used for the oxidative hydroxylation of 4-methoxyphenylboronic acid to 4-methoxyphenol under visible-light irradiation. The attractive catalytic performance mainly resulted from efficient mass transfer and the maintenance of the chemical properties of the cationic Ru complex in the H-CPPs. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

The practical application of rechargeable zinc-air batteries faces challenges stemming from inadequate bifunctional catalysts, contradictory gas-liquid-solid three-phase interfaces, and an ambiguous fundamental understanding. Herein, we propose a chameleon-like bifunctional catalyst comprising ruthenium single-atoms grafted onto nickel-iron layer double hydroxide (RuSA-NiFe LDH). The adaptive oxidation of RuSA-NiFe LDH to oxyhydroxide species (RuSA-NiFeOOH) during charging exposes active sites for the oxygen evolution reaction, while reversible reduction to NiFe LDH during discharge exposes active sites for the oxygen reduction reaction. Additionally, a hierarchical air cathode featuring hydrophilic and hydrophobic layers facilitates the reversible conversion between RuSA-NiFe LDH and RuSA-NiFeOOH, expedites oxygen bubble desorption, and suppresses carbon corrosion. Consequently, our zinc-air batteries demonstrate a high charge/discharge capacity of 100 mAh cm−2 per cycle, a voltage gap of 0.67 V, and an extended cycle life of 2400 h at 10 mA cm−2. We comprehensively elucidate the catalytic reaction thermodynamics and kinetics for the air cathode through electrode potential decoupling monitoring, oxygen bubble desorption tracking, and carbon content quantification. Rechargeable zinc-air batteries hold great promise for energy storage but face several challenges. In this study, the authors introduce a chameleon-like catalyst and a hierarchical air cathode, achieving a 2400-hour cycle life for these batteries. [ABSTRACT FROM AUTHOR]

The impregnation method in the preparation of metal cluster catalysts typically inadvertently introduces single atoms (SAs) into the substrate. However, the question of whether the introduction of SAs will further improve the catalytic activity of cluster systems for specific reactions such as the hydrogen oxidation reaction (HOR) remains unraveled. Herein, we demonstrate Ru clusters anchored on WN nanowires (RuC/WN) show a higher alkaline HOR catalytic activity in comparison with Ru SAs and nanoclusters (NCs)-coupled catalyst anchored on WN nanowires system (RuC,S/WN). Notably, the RuC/WN exhibits superb intrinsic catalytic activity with a mass-normalized exchange current density of 890 mA mg−1PGM, which is among the top level of well developed Ru-based HOR catalysts. Both theoretical simulation and experimental investigation suggest that RuC/WN owns an optimized H* and OH* reaction intermediates for the alkaline HOR, therefore resulting in the excellent intrinsic HOR catalytic performance. [ABSTRACT FROM AUTHOR]

This study employed Environmental DNA (eDNA) barcoding technology to delve into the influence of the tributaries and mainstem on fish diversity and spatiotemporal distribution in a hotspot fish conservation area in the upper Yangtze River. A total of 123 fish species were detected, belonging to 7 orders, 19 families, and 77 genera. The composition of fish species in tributaries is similar to that in mainstem, with higher fish community diversity in tributaries during the spring and summer. Exploration of fish ecotypes revealed significant differences between mainstem and tributaries. The fish community is mainly influenced by key environmental factors such as water temperature, dissolved oxygen, electrical conductivity, and ammonia nitrogen, with a higher impact of these factors on tributaries than on mainstem. In conclusion, while tributaries and mainstem in the Jiangjin section exhibit similarities in fish community composition, there are notable differences in community structure and diversity. Therefore, the protection of not only mainstem but also tributaries and their associated fish habitats is crucial for promoting the overall health and sustainability. [ABSTRACT FROM AUTHOR]

Aerobic composting is an effective way to recycle solid waste. Composting promotes the transformation of degradable organic matter in solid waste into mature manure, precursors of humic substances, by microorganisms widely existed in nature, so as to provide nutrient rich fertilizer for the growth of crops. The community and function of microorganisms play a key role in the successful progress of composting. In recent years, with the vigorous development of molecular biology technology, the succession of microbial community in each stage of composting process has been studied more deeply. Thus, we have a deeper understanding of the metabolic function and functional groups of microorganisms in the composting process. The succession law of microbial community in different stages of composting can be summarized as follows: from mesophilic bacteria and fungi to cellulose decomposing bacteria, then cellulose decomposing bacteria, finally lignin decomposing bacteria. These studies will help us develop microbial additives and improve the efficiency of composting. This paper systematically summarizes the research progress of these molecular biology technologies applied in studies on the microbial community of composting, summarizes the research results of succession changes of microbial community in all stages of composting in recent years, introduces the application of microbial additives in aerobic composting, and prospects the future development of microbial additives. [ABSTRACT FROM AUTHOR]

The structural design of the brake disc of urban rail trains, especially the design of the heat dissipation rib structure, affects the heat dissipation performance of the brake disc. Unreasonable design can lead to poor heat dissipation performance and generate energy consumption caused by large air-pumping resistance. However, the current structural design method for brake discs does not consider material characteristics and continues with materials such as steel and iron. There is no long-term service performance testing applicable to brake disc service conditions for lightweight and high-strength materials such as aluminum matrix composites. In addition, there is no comprehensive and systematic analysis of the structural design of cooling ribs. Therefore, a structure of SiCp/A356 brake discs for urban rail trains was designed in this work. Different from the previous design method, long-term performance testing of materials was conducted first, and then the heat dissipation performance and energy loss performance of different cooling rib structures were systematically analyzed to select the appropriate cooling rib structure. Based on long-term performance testing results, cooling rib optimization, and material forming process, a new brake disc structure was designed. The thermal-fluid–solid multi-field coupling simulation was conducted on the new structure brake disc under emergency braking and full round-trip conditions, and bench tests were conducted to verify the reliability of the simulation. Based on comprehensive simulation and bench test results, the new structure SiCp/A356 brake disc meets the established operating conditions. This design method considers material properties, multi-field coupling simulation, and engineering practice, which can a provide reference for the design of other brake discs and has high engineering application value. [ABSTRACT FROM AUTHOR]

Hydrogenolysis has been explored as a promising approach for plastic chemical recycling. Noble metals, such as Ru and Pt, are considered effective catalysts for plastic hydrogenolysis, however, they result in a high yield of low-value gaseous products. In this research, an efficient bimetallic catalyst was developed by separate impregnation of Ni and Ru on SiO2 support resulting in liquid products yield of up to 83.1 C % under mild reaction conditions, compared to the 65.5 C % yield for the sole noble metal catalyst. The carbon distribution of the liquid products from low density polyethylene hydrogenolysis with Ni-modified catalyst also shifted to a heavier fraction, compared to that with Ru catalyst. Meanwhile, the NiRu catalyst exhibited excellent performance in suppressing the cleavage of the end-chain C–C bond, leading to a methane yield of only 10.4 C %, which was 69% lower than that of the Ru/SiO2 catalyst. Temperature programmed reduction and desorption of hydrogen and propane were further conducted to reveal the detailed mechanism of low density polyethylene hydrogenolysis over the bimetallic catalyst. The results suggested that the Ni-Ru alloy exhibited stronger H adsorption properties indicating improved hydrogen coverage on the catalyst surface thus enhancing the desorption of reaction intermediates. The carbon number distribution was ultimately skewed toward heavier liquid products. [ABSTRACT FROM AUTHOR]

In traffic scenarios, the size of targets varies significantly, and there is a limitation on computing power. This poses a significant challenge for algorithms to detect traffic targets accurately. This paper proposes a new traffic target detection method that balances accuracy and real-time performance—Deep and Filtered You Only Look Once (DF-YOLO). In response to the challenges posed by significant differences in target scales within complex scenes, we designed the Deep and Filtered Path Aggregation Network (DF-PAN). This module effectively fuses multi-scale features, enhancing the model's capability to detect multi-scale targets accurately. In response to the challenge posed by limited computational resources, we design a parameter-sharing detection head (PSD) and use Faster Neural Network (FasterNet) as the backbone network. PSD reduces computational load by parameter sharing and allows for feature extraction capability sharing across different positions. FasterNet enhances memory access efficiency, thereby maximizing computational resource utilization. The experimental results on the KITTI dataset show that our method achieves satisfactory balances between real-time and precision and reaches 90.9% mean average precision(mAP) with 77 frames/s, and the number of parameters is reduced by 28.1% and the detection accuracy is increased by 3% compared to the baseline model. We test it on the challenging BDD100K dataset and the SODA10M dataset, and the results show that DF-YOLO has excellent generalization ability. [ABSTRACT FROM AUTHOR]

We demonstrate a genuine method for three-dimensional pictorial reconstructions of two-dimensional, three-dimensional, and hybrid specimens based on confocal Raman data collected in a back-scattering geometry of a 532-nm setup. The protocol, or the titular PRISM (Phase-Resolved Imaging Spectroscopic Method), allows for sub-diffractive and material-resolved imaging of the object's constituent material phases. The spacial component comes through either the signal distal attenuation ratio (direct mode) or subtle light-matter interactions, including interference enhancement and light absorption (indirect mode). The phase component is brought about by scrutinizing only selected Raman-active modes. We illustrate the PRISM approach in common real-life examples, including photolithographically structured amorphous Al2O3, reactive-ion-etched homoepitaxial SiC, and Chemical Vapor Deposition graphene transferred from copper foil onto a Si substrate and AlGaN microcolumns. The method is implementable in widespread Raman apparatus and offers a leap in the quality of materials imaging. The lateral resolution of PRISM is stage-limited by step motors to 100 nm. At the same time, the vertical accuracy is estimated at a nanometer scale due to the sensitivity of one of the applied phenomena (interference enhancement) to the physical property of the material (layer thickness). [ABSTRACT FROM AUTHOR]

The microscopic reaction pathway plays a crucial role in determining the electrochemical performance. However, artificially manipulating the reaction pathway still faces considerable challenges. In this study, we focus on the classical acidic water oxidation based on RuO2 catalysts, which currently face the issues of low activity and poor stability. As a proof-of-concept, we propose a strategy to create local structural symmetry but oxidation-state asymmetric Mn4-δ-O-Ru4+δ active sites by introducing Mn atoms into RuO2 host, thereby switching the reaction pathway from traditional adsorbate evolution mechanism to oxide path mechanism. Through advanced operando synchrotron spectroscopies and density functional theory calculations, we demonstrate the synergistic effect of dual-active metal sites in asymmetric Mn4-δ-O-Ru4+δ microstructure in optimizing the adsorption energy and rate-determining step barrier via an oxide path mechanism. This study highlights the importance of engineering reaction pathways and provides an alternative strategy for promoting acidic water oxidation. Microscopic reaction pathways are crucial for electrochemical performance, but manipulating them remains challenging. Here, the authors report an approach that involves integrating Mn into RuO2 catalysts to switch the reaction mechanism of the oxygen evolution reaction from a traditional single metal-site adsorbate evolution mechanism to a different dual-metal-site oxide path mechanism. [ABSTRACT FROM AUTHOR]

We give an effective bound on how much time orbits of a unipotent group U on an arithmetic quotient G/Γ can stay near homogeneous subvarieties of G/Γ corresponding to ℚ-subgroups of G. In particular, we show that if such a U-orbit is moderately near a proper homogeneous subvariety of G/Γ for a long time, it is very near a different homogeneous subvariety. Our work builds upon the linearization method of Dani and Margulis. Our motivation in developing these bounds is in order to prove quantitative density statements about unipotent orbits, which we plan to pursue in a subsequent paper. New qualitative implications of our effective bounds are also given. [ABSTRACT FROM AUTHOR]

In food circular economy, the utilization of food manufacturing side streams (FMSS) offers significant potential instead of being discarded. However, reincorporating FMSS into the food value chain raises food safety concerns due to potential food hazards. This perspective explores food safety risks associated with circular management of FMSS by using a 'Quad-Modal hazard dynamic' approach with case studies. Future research and advancements in food safety control strategies are also discussed. [ABSTRACT FROM AUTHOR]

Formaldehyde (HCHO) is a human toxin that is both a pollutant and endogenous metabolite. HCHO concentrations in human biological samples are reported in the micromolar range; however, accurate quantification is compromised by a paucity of sensitive analysis methods. To address this issue, we previously reported a novel SPME–GC–MS-based HCHO detection method using cysteamine as an HCHO scavenger. This method showed cysteamine to be a more efficient scavenger than the widely used O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine, and enabled detection of aqueous HCHO in the nanomolar range and quantification in the micromolar range. However, quantification in this range required immersive extraction of the HCHO-derived thiazolidine, while a high background signal was also observed. Following on from these studies, we now report an optimised head-space extraction SPME–GC–MS method using cysteamine, which provides similarly sensitive HCHO quantification to the immersive method but avoids extensive wash steps and is therefore more amenable to screening applications. However, high background HCHO levels were still observed A Complementary GC–MS analyses using a 2-aza-Cope-based HCHO scavenger also revealed high background HCHO levels; therefore, the combined results suggest that HCHO exists in high (i.e. micromolar) concentration in aqueous samples that precludes accurate quantification below the micromolar range. This observation has important implications for ongoing HCHO quantification studies in water, including in biological samples. [ABSTRACT FROM AUTHOR]

Thermo-Calc and DICTRA software simulations were used to predict the feasibility of Co–Ni–Fe additives applied to WC/HSS composites, and WC–Co–Ni–Fe/HSS composites were prepared. The elemental diffusion behavior in the WC-steel composites using Co, Ni and Fe additive was investigated. The results showed that the Co–Ni–Fe additive forms more liquid phase at lower temperatures, and the Co–Ni–Fe additive has a larger pre-exponential factor and lower diffusion activation energy. The results of the experimental sample demonstrate that the Co–Ni–Fe elements in the WC region are uniformly distributed around the WC. The Co, Ni, Fe and Cr elements mutual diffuse in the WC and HSS regions, with the Co and Fe elements being more pronounced. The diffusion of W is almost non-existent. The Co–No–Fe additive contributes to the bonding of the WC to the HSS and facilitates the densification of the WC region. The simulation results are consistent with the experimental results. [ABSTRACT FROM AUTHOR]

This paper is devoted to the study of a time-discrete scheme and its corresponding fully discretization approximating a d-dimensional chemotaxis model describing tumor invasion, d ≤ 3. This model describes the chemotactic attraction experienced by the tumor cells and induced by a so-called active extracellular matrix, which is a chemical signal produced by a biological reaction between the extracellular matrix and a matrix-degrading enzyme. In order to construct the numerical approximations and to control the chemo-attraction term in the tumor cells equation, we introduce an equivalent model with a new variable given by the gradient of the active extracellular matrix and use an inductive strategy. Then, we consider a first-order and non-linear time-discrete scheme which is mass-conservative and possesses the property of positivity for all the biological variables. After, we study the corresponding fully discrete finite element with “mass-lumping” approximation proving well-posedness, mass-conservation and the non-negativity of the extracellular matrix, the degrading enzyme, and the active extracellular matrix. In addition, we obtain uniform strong estimates required in the convergence analysis, and we prove optimal error estimates and convergence towards regular solutions. Finally, we provide some numerical results in agreement with our theoretical analysis with respect to the positivity and the error estimates. [ABSTRACT FROM AUTHOR]

Electrochemical energy technologies are crucial for a sustainable future, promising to transform energy generation, storage and use with improved efficiency and environmental responsibility. In this study, Fe was integrated into the MCM-48 framework to create a modified mesoporous structure to be used as electrodes for electrochemical storage applications. The materials were thoroughly characterized using various spectroscopic and non-spectroscopic techniques, including XRD, XPS, UV-Vis (DRS), FT-IR, N2 adsorption-desorption analysis, SEM with EDX, ICP-OES, TEM, TGA and DSC. Cyclic voltammetry and galvanometric charge-discharge studies revealed that the Fe-MCM-48 sample with Si: Fe molar ratio of 20 (Fe-MCM-48 (20)) exhibited pseudocapacitive behaviour, showcasing higher capacitance value of up to 787 F g− 1 at a current density of 1 A g− 1. The findings undeniably indicate that Fe-MCM-48 (20) holds promise as a highly effective electrode material for advancing energy storage technologies like supercapacitors. [ABSTRACT FROM AUTHOR]

A control reconstruction problem for dynamic deterministic affine-control systems is considered. This problem consists of constructing piecewise constant approximations of an unknown control generating an observed trajectory from discrete inaccurate measurements of this trajectory. It is assumed that the controls are constrained by known nonconvex geometric constraints. In this case, sliding modes may appear. To describe the impact of sliding modes on the dynamics of the system, the theory of generalized controls is used. The notion of normal control is introduced. It is a control that generates an observed trajectory and is defined uniquely. The aim of reconstruction is to find piecewise constant approximations of the normal control that satisfy given nonconvex geometric constraints. The convergence of approximations is understood in the sense of weak convergence in the space superscript 퐿 2 . A solution to the control reconstruction problem is proposed. [ABSTRACT FROM AUTHOR]

To counterbalance the abilities of global exploration and local exploitation of algorithm and enhance its comprehensive performance, a multi-objective particle swarm optimization with a competitive hybrid learning strategy (CHLMOPSO) is put forward. With regards to this, the paper first puts forward a derivative treatment strategy of personal best to promote the optimization ability of particles. Next, an adaptive flight parameter adjustment strategy is designed in accordance with the evolutionary state of particles to equilibrate the exploitation and exploration abilities of the algorithm. Additionally, a competitive hybrid learning strategy is presented. According to the outcomes of the competition, various particles decide on various updating strategies. Finally, an optimal angle distance strategy is proposed to maintain archive effectively. CHLMOPSO is compared with other algorithms through simulation experiments on 22 benchmark problems. The results demonstrate that CHLMOPSO has satisfactory performance. [ABSTRACT FROM AUTHOR]

The sluggish kinetics of Volmer step in the alkaline hydrogen evolution results in large energy consumption. The challenge that has yet well resolved is to control the water adsorption and dissociation. Here, we develop biaxially strained MoSe2 three dimensional nanoshells that exhibit enhanced catalytic performance with a low overpotential of 58.2 mV at 10 mA cm−2 in base, and long-term stable activity in membrane-electrode-assembly based electrolyser at 1 A cm−2. Compared to the flat and uniaxial-strained MoSe2, we establish that the stably adsorbed OH engineer on biaxially strained MoSe2 changes the water adsorption configuration from O-down on Mo to O-horizontal on OH* via stronger hydrogen bonds. The favorable water dissociation on 3-coordinated Mo sites and hydrogen adsorption on 4-coordinated Mo sites constitute a tandem electrolysis, resulting in thermodynamically favorable hydrogen evolution. This work deepens our understanding to the impact of strain dimensions on water dissociation and inspires the design of nanostructured catalysts for accelerating the rate-determining step in multi-electron reactions. Hydroxide is the most abundant anion in alkaline solutions, but its impact on alkaline water electrolysis remains unclear. Herein, the authors report a biaxial strain induced OH engineer on MoSe2 to accelerate alkaline hydrogen evolution by modifying the water dissociation. [ABSTRACT FROM AUTHOR]

Catalyst preparation, reaction process conditions and kinetics of the selective hydrogenation of fatty acid methyl esters (FAME) over a noble metal catalyst were studied. Two catalysts were prepared by impregnation of γ-Al2O3 with Ru (1% mass content) as active metal and Sn and B as modifiers (2% mass content), and with different Sn/Ru ratios of 2 and 4. FAME derived from biomass, an environment friendly raw material, was used for the preparation of fatty alcohols by selective hydrogenolysis of the ester group to an alcohol group. The results were analyzed with a simple kinetic model using lumped pseudocomponents. When comparing the two catalysts it was found that the most effective catalyst for producing oleyl alcohol was the one with a Sn/Ru ratio of 2, RuSn2–B. The maximum production of alcohols and alkanes was achieved with this catalyst at 290 °C. At 270 °C a lower production of alkanes was obtained but with a similar yield of alcohols. Both reaction conditions and catalyst composition were found to be important factors influencing alcohol production. Two types of active sites were identified on the studied catalysts: the unmodified Ru0 metal for dissociating hydrogen and the modified metal, (Ru0–(SnOx)2, for adsorbing the C=C carbons. RuSn2–B seemingly exhibited an appropriate balance of these sites. The kinetic model included the reactions of esters, hydrogen, alcohols and deoxygenated hydrocarbons. These were studied with lumped variables with no distinction of individual specific molecules. In spite of this, the model provided a very good fit of the experimental data indicating that the reaction is rather insensitive to secondary features like carbon chain length or group positions. [ABSTRACT FROM AUTHOR]

The direct co-conversion of methane and carbon dioxide into valuable chemicals has been a longstanding scientific pursuit for carbon neutrality and combating climate change. Herein, we present a photo-driven chemical process that reforms these two major greenhouse gases together to generate green methanol and CO, two high-valued industrial chemicals. Isotopic labeling and control experiments indicate an oxygen-atom-graft occurs, wherein CO2 transfers one O into the C–H bond of CH4 via photo-activated interfacial catalysis with AuPd nanoparticles supported on GaN. The photoexcited AuPd/GaN interface effectively orchestrates the CH4 oxidation and the CO2 reduction producing 13.66 mmol g−1 of CH3OH yield over 10 h. This design provides a solid scientific basis for the photo-driven oxygen-atom-grafting process to be further extended to visible light region. The direct co-conversion of CH4 and CO2 into valuable chemicals has been a longstanding scientific pursuit. Here, the authors present a photo-driven process that reforms these greenhouse gases together to generate CH3OH and CO over AuPd/GaN. [ABSTRACT FROM AUTHOR]

Electrocatalysis holds the key to enhancing the efficiency and cost-effectiveness of water splitting devices, thereby contributing to the advancement of hydrogen as a clean, sustainable energy carrier. This study focuses on the rational design of Ru nanoparticle catalysts supported on TiN (Ru NPs/TiN) for the hydrogen evolution reaction in alkaline conditions. The as designed catalysts exhibit a high mass activity of 20 A mg−1Ru at an overpotential of 63 mV and long-term stability, surpassing the present benchmarks for commercial electrolyzers. Structural analysis highlights the effective modification of the Ru nanoparticle properties by the TiN substrate, while density functional theory calculations indicate strong adhesion of Ru particles to TiN substrates and advantageous modulation of hydrogen adsorption energies via particle-support interactions. Finally, we assemble an anion exchange membrane electrolyzer using the Ru NPs/TiN as the hydrogen evolution reaction catalyst, which operates at 5 A cm−2 for more than 1000 h with negligible degradation, exceeding the performance requirements for commercial electrolyzers. Our findings contribute to the design of efficient catalysts for water splitting by exploiting particle-support interactions. Designing efficient and stable electrocatalysts for water splitting is of great interest for H2 fuel production. Here, the authors present a Ru nanoparticle catalyst on TiN, achieving 20 A mg−1 Ru at 63 mV in alkaline conditions, and operating at 5 A cm−2 for over 1000 hours in an anion exchange membrane electrolyzer. [ABSTRACT FROM AUTHOR]

This research tries to establish the emissions diffusion model of high-speed motor vehicles on the Capital Ring Expressway (CRE) around Beijing, China, applying the MOVES and the CALPUFF models. Data required for this study have been collected from different sources. The results show that small buses and large trucks have the highest pollutant emissions on the CRE. The pollutants like CO and HC mainly comes from gasoline vehicles, while NOx, PM10 and PM2.5 comes from diesel vehicles. The average concentrations of the diffusion of CO, NOx, CH4, PM10, and PM2.5 along with the CRE are 6.5 mg/m3, 2.3 mg/m3, 0.27 mg/m3, 0.055 mg/m3 and 0.056 mg/m3 respectively. The results of this study have practical significance and influence on the emission reduction and concentration control strategies under different circumstances, and put forward suggestions on changing transportation modes, strengthening supervision and so on. It has produced a number of recommendations for the policy makers including (1) active promotion of new energy vehicles on expressways, (2) strategic change of the mode of passenger and freight transportation on expressways, (3) strengthen traffic management and supervision of motor vehicles on expressways, and (4) strengthen vegetation protection in rural and ecologically sound areas along the route. [ABSTRACT FROM AUTHOR]

Ruthenium complexes with facially coordinating tripodal phosphine ligands are privileged catalysts for a broad range of (de-)hydrogenation-based transformations. Among these, C–O bond hydrogenolysis holds potential for the depolymerisation of both the biopolymer lignin and epoxy resins applied in wind turbine blades, aircrafts and more. However, this methodology is poorly understood in mechanistic terms. Here, we present a detailed investigation on the triphos-Ru catalysed C–O bond scission on a molecular level. A combination of experimental, spectroscopical and theoretical studies elucidates the reactivity of the ruthenium trimethylenemethane precatalyst, revealing the key roles of ruthenium phenolates in both catalyst activation as well as the catalytic cycle itself. Furthermore, a Ru(0)/Ru(II) oxidative addition into the C–O bond is disclosed, with a triphos-Ru(0) dihydrogen complex as entry point. With the molecular nature of the operating triphos-Ru species and the thermodynamics and kinetics of the catalysis unravelled, improvements of established methods as well as design of related transformations may become possible. Ruthenium complexes with facially coordinating tripodal phosphine ligands are privileged catalysts for a broad range of (de-)hydrogenation-based transformations but the mechanism remains poorly understood. Here the authors present a detailed investigation on the triphos-Ru catalysed C–O bond scission on a molecular level. [ABSTRACT FROM AUTHOR]

The chemical recycling of polyester wastes is of great significance for sustainable development, which also provides an opportunity to access various oxygen-containing chemicals, but generally suffers from low efficiency or separation difficulty. Herein, we report anatase TiO2 supported Ru and Mo dual-atom catalysts, which achieve transformation of various polyesters into corresponding diols in 100% selectivity via hydrolysis and subsequent hydrogenation in water under mild conditions (e.g., 160 °C, 4 MPa). Compelling evidence is provided for the coexistence of Ru single-atom and O-bridged Ru and Mo dual-atom sites within this kind of catalysts. It is verified that the Ru single-atom sites activate H2 for hydrogenation of carboxylic acid derived from polyester hydrolysis, and the O-bridged Ru and Mo dual-atom sites suppress hydrodeoxygenation of the resultant alcohols due to a high reaction energy barrier. Notably, this kind of dual-atom catalysts can be regenerated with high activity and stability. This work presents an effective way to reconstruct polyester wastes into valuable diols, which may have promising application potential. Chemical recycling of polyester wastes is of great significance for sustainable development. Here the authors report a Ru and Mo dual-atom catalyst for reconstructing polyester wastes into diols in water under mild conditions. [ABSTRACT FROM AUTHOR]

Because non-pharmaceutical interventions are an essential part of pandemic influenza control planning, the complex impacts of such measures must be clearly and comprehensively understood. Research has examined the health and environmental effects of non-pharmaceutical interventions, but has not yet examined their socio-political effects. Using data from the COVID-19 pandemic period, this article examined the impact of non-pharmaceutical interventions on people's online participation in China in 2020. Using the difference-in-differences method, it showed that counter-COVID-19 non-pharmaceutical interventions in Chinese cities led to a 0.217 increase in daily messages to City Party Secretaries, which were consistent with findings of an alternative counterfactual estimator and other additional robustness tests. The effects of non-pharmaceutical interventions were larger in cities with better economic conditions, better telecommunication foundations, and better-educated residents. Mechanism analyses implied that the increase in online participation resulted from not only citizens' increased actual demand for seeking help and expressing thanks but also their active coproduction activities to address the crisis. Overall, this study identified the socio-political effects of counter-pandemic non-pharmaceutical interventions and discussed how these interventions could be optimized. [ABSTRACT FROM AUTHOR]

In developing B cells, V(D)J recombination assembles exons encoding IgH and Igκ variable regions from hundreds of gene segments clustered across Igh and Igk loci. V, D and J gene segments are flanked by conserved recombination signal sequences (RSSs) that target RAG endonuclease1. RAG orchestrates Igh V(D)J recombination upon capturing a JH-RSS within the JH-RSS-based recombination centre1–3 (RC). JH-RSS orientation programmes RAG to scan upstream D- and VH-containing chromatin that is presented in a linear manner by cohesin-mediated loop extrusion4–7. During Igh scanning, RAG robustly utilizes only D-RSSs or VH-RSSs in convergent (deletional) orientation with JH-RSSs4–7. However, for Vκ-to-Jκ joining, RAG utilizes Vκ-RSSs from deletional- and inversional-oriented clusters8, inconsistent with linear scanning2. Here we characterize the Vκ-to-Jκ joining mechanism. Igk undergoes robust primary and secondary rearrangements9,10, which confounds scanning assays. We therefore engineered cells to undergo only primary Vκ-to-Jκ rearrangements and found that RAG scanning from the primary Jκ-RC terminates just 8 kb upstream within the CTCF-site-based Sis element11. Whereas Sis and the Jκ-RC barely interacted with the Vκ locus, the CTCF-site-based Cer element12 4 kb upstream of Sis interacted with various loop extrusion impediments across the locus. Similar to VH locus inversion7, DJH inversion abrogated VH-to-DJH joining; yet Vκ locus or Jκ inversion allowed robust Vκ-to-Jκ joining. Together, these experiments implicated loop extrusion in bringing Vκ segments near Cer for short-range diffusion-mediated capture by RC-based RAG. To identify key mechanistic elements for diffusional V(D)J recombination in Igk versus Igh, we assayed Vκ-to-JH and D-to-Jκ rearrangements in hybrid Igh–Igk loci generated by targeted chromosomal translocations, and pinpointed remarkably strong Vκ and Jκ RSSs. Indeed, RSS replacements in hybrid or normal Igk and Igh loci confirmed the ability of Igk-RSSs to promote robust diffusional joining compared with Igh-RSSs. We propose that Igk evolved strong RSSs to mediate diffusional Vκ-to-Jκ joining, whereas Igh evolved weaker RSSs requisite for modulating VH joining by RAG-scanning impediments.Experiments in mouse models, and in cell lines that only allow primary Vκ-to-Jκ rearrangements, enable characterization of the mechanisms of V(D)J recombination. [ABSTRACT FROM AUTHOR]

For the first time, Ti2SnC powder was directly fabricated by high-temperature ball milling with Sn, Ti, and graphite as reactants and was compared with Ti2SnC formation by mechanical alloying and thermal treatment. Phase changes and microstructure of powder samples during milling and thermal treatment were evaluated by X-ray diffraction, high-resolution scanning electron microscopy, and transition electron microscopy. Results presented that TiC, Ti6Sn5, and Ti5Sn3 formed after 40 h of traditional milling, and finally, Ti2SnC with some impurities like TiC formed after thermal treatment. Because of the high-temperature ball milling, Ti5Sn3 and TiC were formed after 5 h of milling. When milling time reached 10 h, TiC and Ti5Sn3 reacted together and Ti2SnC was formed. According to the present work, the Ti2SnC formed at a lower temperature and time of milling in comparison to conventional mechanical alloying and heat treatment. [ABSTRACT FROM AUTHOR]