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Mg–3Y/Al composites were produced through accumulated rolling bonding. During annealing, Al–Y precipitates were synthesized in-situ within the Mg–3Y/Al composites through solid diffusion reactions. In these composites, the volume fraction of the interface layer containing abundant Al–Y precipitates can reach approximately 74% after three passes of accumulated rolling bonding and diffusion annealing. At room temperature, the Mg–3Y/Al composite exhibits increased strength (∼273.9 MPa) but reduced ductility (∼3.5%) compared to the base Mg–3Y alloy (∼191.0 MPa, ∼30%), due to the presence of numerous Al–Y precipitates and residual dislocations. These Al–Y precipitates display remarkable thermal stability, maintaining their size without significant coarsening even after annealing at 400 °C for 1–4 h, thereby contributing to the exceptional thermal stability observed in Mg–3Y/Al samples. After annealing at 400 °C for 4 h, the tensile strength of the Mg–3Y/Al samples remained unchanged, while the ductility increased to 8.5%. At 300 °C, the Mg–3Y/Al composite demonstrates exceptional high-temperature strength (179.9 MPa), significantly surpassing that of the original Mg–3Y alloy (110.6 MPa). Moreover, compared to the original Mg–3Y alloy and magnesium alloys reported in the literature, the Mg–3Y/Al composite exhibits a higher RE-equivalent strength at 300 °C. This enhanced strength is primarily attributed to precipitation strengthening induced by fine Al–Y precipitates. These findings underscore that introducing fine Al–Y precipitates through a solid diffusion reaction is an effective approach for achieving outstanding high-temperature strength in magnesium alloys.

To reduce the mechanical sensitivity of CL-20, this study is based on the surface modification of CL-20, and explores the effects of two preparation processes, the water solution-suspension method and the phase separation method, on the coating process of CL-20. Based on the structural characteristics of surfactants, a formulation was devised, using 2-cyanoethyltriethoxysilane (SCA2) as the surfactant and microcrystalline wax as the desensitizer. The samples underwent comprehensive characterization employing SEM, XPS, DSC, XRD, friction sensitivity testing, and impact sensitivity testing to evaluate both their structural composition and inherent properties. The results showed that the composite particles prepared using the phase separation method displayed a compact coating layer on CL-20 surfaces. Specifically, the composite particle CL-20@SCA2/Wax-P, which contained the surfactant, exhibited a thin and dense film on its surface. The proportion of -NO2groups on the surface of the composite particles experienced a reduction of 13.12% compared with CL-20. The crystal form of CL-20 remained unchanged in four composite particles. The decomposition peak temperatures and activation energy of all four composite particles were decreased, resulting in reduced thermal stability. The critical friction sensitivity load for composite particles produced via the aqueous suspension method is 252 N, whereas for those prepared using the phase separation method, it elevates to 360 N. The characteristic drop height (H50) of composite particles prepared by the phase separation method increased significantly, 34 cm for CL-20/W-P composite particles and 55 cm for CL-20@SCA2/W-P composite particles, compared with the raw CL-20. These results suggest that the utilization of SCA2 effectively modified the surface of CL-20, and the composite particles prepared using the phase separation method demonstrated a considerable reduction in mechanical sensitivity.

Logistics service as an important key link between online take-out platform and offline users. Its quality directly affects customer service perception and experience, but also lead to the heart of the willingness of consumers to re-use. So a framework constructed for understanding logistics service quality on consumers’ behavioral psychology is focused on, suitable service encounter points (function encounter, the distributor encounter, service results encounter, word-of-mouth encounter have been identified from the literature and the connotation of service encounter in logistics service. In view of the limitations of traditional statistical analysis methods in dealing with Likert scale data and the fuzziness of scale evaluation grade, a combination of statistical analysis and fuzzy comprehensive evaluation is used to analyze the scale. Then combined with the logical connection between perceived value, customer satisfaction and behavioral psychology in the classic American Customer Satisfaction Index Model model, emotional attachment of platform as the adjustment variable. The findings indicate that the four encounter points of online take-out logistics service are positively related to customer purchase satisfaction and perceived value. Additionally, the most significant impact on the perceived value is the functional encounter and the distributor encounter, and the most significant impact on the customer satisfaction is the service results encounter and word-of-mouth encounter; platform emotional attachment positively regulates the positive correlation between perceived value/customer satisfaction and behavioral psychology. So this research extends the theory of service encounter to online delivery logistics service quality evaluation, which is a further expansion of the connotation of service encounter and provides the platform with suggestions to pay attention to the flaw of logistics service and improve service.

Commercial pure Ti sheets with an initial wavy profile were rolled and annealed to fabricate heterostructure. Microstructure investigations by electron backscatter diffraction (EBSD) show that a dual-gradient microstructure including gradient grain size and gradient texture is developed, where the average grain size decreases and the split-basal texture gets stronger from the trough zone to the crest zone. Finite element simulations of the rolling process were carried out to investigate the formation mechanism of the dual-gradient microstructure. Uniaxial tension tests were performed to evaluate the mechanical properties, and the digital image correlation (DIC) technique was used to reveal the evolution of local strain during tension. When tensioned along the rolling direction, sheets consisting of both crest and trough zones achieve better elongation compared with the single crest and single trough counterparts. When tensioned along the transverse direction, better elongation is also obtained for the sheets with an initial wavy profile compared with the straight counterparts, which is mainly attributed to the dispersing local strain caused by the gradient texture. The results reported in this study may be inspirational to the design and fabrication of heterostructural hexagonal closed-packed metals.

This paper analyzes and compares the deformation, failure characteristics, and energy characteristics of coal and rock under uniaxial compression. It is considered that the change laws of the total stress–strain relationship curves of raw coal and sandstone samples are similar, and they all exhibit the primary fracture compaction and closure stage, elastic deformation stage, fracture expansion stage and stress drop stage. The failure mode of coal and rock is a predominantly columnar splitting, and the fractured coal and rock bite each other. The ultimate bearing capacity, elastic modulus and peak strain of coal samples are small for sandstone. Under uniaxial compression, the ultimate bearing capacity, elastic modulus, and peak strain of coal samples were 46.17%, 63.32%, and 69.54% of sandstone, respectively. In the compaction stage, the proportion of releasable elastic energy of the coal sample was higher than that of dissipated energy, while that of the sandstone sample is the opposite. The proportion of releasable elastic energy of coal samples in other stages was higher than that of dissipated energy, and more than 80% of the total energy absorbed by coal and rock specimens in the loading process was stored in the form of releasable elastic energy. Other total energy was dissipated by the internal defects of the samples during compaction, sliding and new micro-cracks in the yield stage.

AZ31/Mg3Y composites with a layer thickness of 100–200 μm were fabricated by accumulated rolling bonding (ARB), which was followed by diffusion annealing at 300 °C for 0–32 h. An interface layer, containing numerous Al-Y precipitates, is formed in the Mg3Y layer that is adjacent to the interface as a result of Al diffusing from the AZ31 layers into the Mg3Y layers. The thickness of the interface layer gets increased and more precipitates are formed in the interface layer with the extension of the annealing time. The microhardness of the AZ31 and Mg3Y layer decreases firstly and then reaches a stable value, while the microhardness of the interface layer increases gradually with the extension of the annealing time. The AZ31/Mg3Y composites exhibit equivalent strength but increased ductility after diffusion annealing, in comparison to the as-rolled AZ31/Mg3Y composite. In addition, the AZ31/Mg3Y composites after annealing always present higher strength and ductility than AZ31/AZ31 composite, which was fabricated by the same process as that for the AZ31/Mg3Y composites. Hetero-deformation induced strengthening also plays an important role in the excellent strength and ductility of the annealed AZ31/Mg3Y composite. This study can provide a direction for improving the plasticity and strength of magnesium alloys synergistically.

• The microstructure evolution and deformation behaviors in the Mg-2Gd and AZ31B alloys were directly observed via the quasi- in-situ electron backscatter diffraction technique. • The microcracks nucleation mechanism that nucleated at the ND-surface of Mg-Gd bent samples were significantly different from the traditional AZ31 alloys. • The relationship between the topology of the grain boundary network and the microcracks nucleation during the bending process was discussed. In this work, the in-situ observation of the microstructure in the Mg-2Gd (wt%) alloys during V-bending tests was operated. The microstructure and texture evolutions were characterized by the in-situ electron backscatter diffraction (EBSD), scanning electron microscopy (SEM) and the high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) technique. The results revealed a unique microcracks nucleation mechanism in the Mg-Gd alloys compared with the traditional Mg alloy (AZ31 alloy). The microcrack was nucleated at the grain boundary for the Mg-2Gd alloy and in the intragranular for the AZ31 alloy during the bending process. This difference mode between the Mg-Gd and the AZ31 alloys was mainly attributed to the more random topology of the grain boundary network, the lower grain boundary cohesion and the enhanced hinder ability for the dislocations due to the segregated Gd atoms in the Mg-Gd alloy. Furthermore, the microcracks that had a large angle θ with the extruded direction (ED) in the Mg-Gd alloys were preferred nucleated since grain boundaries had the larger normal stress during the bending process. [Display omitted] [ABSTRACT FROM AUTHOR]

The digital economy and energy are crucial drivers of economic transformation, and the global development trend is toward the deep integration of the two. Previous studies carried out at the provincial scale, show it is difficult to grasp the change characteristics of prefecture-level cities. From the scale of urban agglomeration, energy management problems in different regions can be more accurately grasped. This study examines the Beijing-Tianjin-Hebei area and its seven surrounding regions, commonly known as the “2 + 26” cities. Panel data from 28 prefecture-level cities between 2011 and 2019 are utilized for analysis. First, the area's energy efficiency was assessed using the DEA-SBM model. Second, the development coordination relationship among the digital system and energy system is evaluated by using the coupling coordination degree model. Finally, the process of coupling coordination of digital-energy systems affecting energy efficiency was examined using a three-step stepwise regression and bootstrap mediation model. The findings demonstrate that: (1) The “2 + 26” cities' energy efficiency is considerably different. The distribution of the high efficiency zone changes from “high in the south and low in the north” to the state of radiating southward with Beijing and Tianjin as the center. (2) “2 + 26” cities are in the dynamic evolution stage of low to medium coupling degree, accounting for 89.3 % of all cities. The coupling coordination degree of digital-energy system has increased throughout the entire city by 49 %. (3) Energy efficiency improved by 64.7 % while the coupling coordination degree of the digital energy system grew by 1 %. The total effect of technical efficiency changes on energy efficiency accounted for 8.2 %. The research results could provide differentiated policy recommendations for regional energy use.

In this work, we investigated the microstructure and the mechanical properties of extruded Mg-xGd-0.5Mn alloys (GMx0) with the variation of Gd content (0, 2, 4, 7 wt.%). For the GM00 alloys with no Gd content, the typical basal fiber texture (BFT) was formed, which led to similar mechanical properties to the pure Mg. However, with the dilute addition of the Gd element, the texture was transformed into ED-split texture, termed Rare Earth (RE)-texture, which improved the ductility significantly. As the Gd content increased, the texture was transformed from RE-texture to the BFT, decreasing the ductility and increasing the stretch yield strength. Furthermore, the electron backscattered diffraction (EBSD)-assisted slip trace analysis method and the Visco-Plastic Self-Consistent (VPSC) model were utilized to uncover the strain coordination mechanism variation. The results indicated that non-basal slip systems, including prismatic slip and the pyramidal slip, were activated more frequently with the increase of Gd content. The Gd addition has more excellent facilitation for the pyramidal slip than the prismatic slip. However, this promotion effect of non-basal slip systems was insufficient to compensate for the overall reduction in ductility owing to the texture change.

Recent advances in humidity sensors have emphasized their critical roles in various fields, from food processing to healthcare. Vermiculite (V), as a two-dimensional (2D) material, can be exploited in humidity sensors with numerous advantages such as low cost, thermal stability, and ease of functionalization for large-scale manufacturing. Here we demonstrated that the 2D characteristics of V, combined with ultrafast transport of confined water in its nanocapillaries, significantly enhance the rapid adsorption and desorption of water, thereby endowing the humidity sensor with rapid sensing capabilities. Furthermore, we employed the ionic liquid (IL), [EMIM][BF4] as an intercalating agent to modify V utilizing the electrostatic and hydrogen bonding interactions between them. The ultrafast transport of water in the V-[EMIM][BF4] membrane was not only improved, but the confined water in nanocapillaries was also transformed from a “constrained” to a comparatively “relaxed” state. This “relaxed” water allowed it to rotate into suitable orientation for efficient proton transfer. Consequently, the V-[EMIM][BF4] membrane-based sensor exhibited the improved transient response of 5 s and 34 s in the range of 30%–80% relative humidity. This study leveraged the benefits of IL-modified V membranes to pave the way for cost-effective humidity sensing devices with rapid responses.

Crassulacean acid metabolism (CAM) has high water-use efficiency (WUE) and is widely recognized to have evolved from C3photosynthesis. Different plant lineages have convergently evolved CAM, but the molecular mechanism that underlies C3-to-CAM evolution remains to be clarified. Platycerium bifurcatum(elkhorn fern) provides an opportunity to study the molecular changes underlying the transition from C3to CAM photosynthesis because both modes of photosynthesis occur in this species, with sporotrophophyll leaves (SLs) and cover leaves (CLs) performing C3and weak CAM photosynthesis, respectively. Here, we report that the physiological and biochemical attributes of CAM in weak CAM-performing CLs differed from those in strong CAM species. We investigated the diel dynamics of the metabolome, proteome, and transcriptome in these dimorphic leaves within the same genetic background and under identical environmental conditions. We found that multi-omic diel dynamics in P. bifurcatumexhibit both tissue and diel effects. Our analysis revealed temporal rewiring of biochemistry relevant to the energy-producing pathway (TCA cycle), CAM pathway, and stomatal movement in CLs compared with SLs. We also confirmed that PHOSPHOENOLPYRUVATE CARBOXYLASE KINASE(PPCK) exhibits convergence in gene expression among highly divergent CAM lineages. Gene regulatory network analysis identified candidate transcription factors regulating the CAM pathway and stomatal movement. Taken together, our results provide new insights into weak CAM photosynthesis and new avenues for CAM bioengineering.

Nine new humulane-derived sesquiterpenoids, ochracenes A–I (1–9), were isolated from the Antarctic fungus Aspergillus ochraceopetaliformisSCSIO 05702. Their structures including absolute configurations were elucidated on the basis of spectroscopic analysis, Mosher’s method, and electronic circular dichroism analysis. Compared with previous humulane-type sesquiterpenoids, ochracenes A–I (1–9) featured novel carbon skeletons with corresponding methyl migration, ring cleavage, and carbon loss. Two unprecedented 8,9-secocyclic sesquiterpenoids (2and 3) exhibited inhibitory effects on lipopolysaccharide-induced NO release in RAW 264.7 mouse macrophage cell lines with IC50values of 14.6 ± 0.5 and 18.3 ± 1.7 μM, respectively.

Introduction of defects and engineering of structure play significant roles in improvement on electrochemical performances of copper sulfide (Cu9S5) as a supercapacitors (SCs) electrode. Herein, a hierarchical rose-shaped Cu9S5 is synthesized by using a facile one-step hydrothermal method and subsequently annealed under different atmospheres and time. X-ray photoelectron spectroscopy (XPS) spectra and scanning electron microscopy (SEM) confirm the presence of sulfur vacancies and changes of morphology in Cu9S5 annealed under argon (Ar) for 2 h (Cu9S5-Ar-2h), which exhibit an effective promotion to the surface redox reactions and ion transition ability proved by the electrochemical measurements. Thus, when the Cu9S5-Ar-2h is used as an SCs electrode, it performs the highest specific capacity of 337 C/g at a scanning rate of 5 mV/s, which is nearly four times that of the pristine Cu9S5 (92 C/g). Moreover, an asymmetric supercapacitor using Cu9S5-Ar-2h as a positive electrode and activated carbon as a negative electrode is designed and assembled, which demonstrates a good energy density of 13.2 Wh/kg at a power density of 789.5 W/kg and an outstanding cycling stability of near 100% after 2000 cycles. This work will provide a feasible strategy to construct advanced electrodes based on transition metal sulfides by annealing treatments.

Power skiving is a highly productive method for manufacturing gears, especially internal gears. However, due to the resharpening errors of the conical skiving tool, the insufficient tool life hinders the large-scale applications of power skiving. This work proposes a novel design method of the cylindrical skiving tool based on deriving the mathematical model of two-parameters conjugate tooth surface of an internal gear. The error-free cutting-edge of the skiving tool is obtained from the intersection curve of the conjugate tooth surface and the rake face with an offset along the tool axis. In the present study, a helical internal gear with 97 teeth, module of 1.5875 mm and helix angle of 23.5° is used for the design of a cylindrical skiving tool with 37 teeth. The numerical analysis results show that the tool axial offset zoff, crossed shaft angle Σand geometric rake angle of tool γ0result in the asymmetrical tool profile and the uneven clearance angles on both flanks. However, the change of the tool helix angle by 0.7° can obtain an even clearance angles on both flanks when zoffis −30 mm. The noninterference height of the cylindrical tool is 48 % more than the conical tool when machining the same workpiece, which means the cylindrical tool is expected to be a longer tool life. Experiments are conducted on a Profilator Type H skiving machine by using the cylindrical skiving tool by the accuracy of DIN 3. The results show the tool design method is effective and applicable to machine a gear by the accuracy of ISO1328-1 level 7.

Xiaonan Garden is the back garden at the Weng family’s former residence, a famed mansion in Jiangnan. Various architectural colored paintings in the Jiangnan style, including a rare paster colored painting, are preserved in the garden. This study examines the wooden support, pigments, and structure of the painting and conducts a series of conservation experiments in situ and in the laboratory. Several conservation problems, such as the manually brushed lime, re-adherence of flaking painting layers, and consolidation of gold foil, were solved, and good results were obtained. Virtual recovery provided a solid foundation for protection and example of research on architectural colored paintings in Jiangnan.

Water is crucial for sustaining life and development. The Nile river basin is one of the river basins supporting human life since the earliest days of human civilization. Currently, with increasing water demand the river basin is experiencing pressures and the water conflict in the region is deepening. The riparian countries are building and planning various unilateral water use schemes along the river to meet their growing water demand. This paper considering the current and predicted water demands of the riparian countries introduces a new approach that should be taken into consideration in the management of the river basin, i.e., the scenario of water bankruptcy. After a careful analysis of the predicated water availability and demand in the river basin the authors believe that water bankruptcy is inevitable in the river basin. The water allocation and water right determination efforts in the river basin should take account this scenario into consideration. Doing this will assist in avoiding water conflicts in the future and ensure the fairness and sustainability of allocation rules.

Ethiopia is currently one of the fastest growing economies in Africa. Due to this rapid growth in economy the country is facing a huge challenge to meet the fast growing energy demand. The major demand comes from industrial, agricultural, service sectors and from the rising household consumption because of the rising standard of living. From among the many other sources of energy, the country identified hydropower to be the key to satisfy the current growing energy demand. When the government decided to develop huge hydropower projects on the country’s major river basins, it not only considered the country’s huge hydropower potential but also the additional social, economic and environmental benefits these multi-purpose hydropower projects bring. These hydropower projects also provide the opportunity to mitigate their minimal negative environmental impacts. This paper will explore the country’s hydropower potential, energy consumption, and future energy demand. Then it discusses the role of hydropower in terms of satisfying the energy demand and the advantages it provides as compared to other alternative energy technologies. Finally, the part hydropower plays in leading the country into a more sustainable energy future is explored as well.

A discrete centrosymmetric (H2O)20(CH3OH)4binary cluster was confined in the cavity of a metal-ligand hybrid [Ag4(bpda)2(bpp)4·14H2O·2CH3OH]n(1) (where bpp = 1,3-bis(4-pyridyl)propane and H2bpda = 2,2'-biphenyldicarboxylic acid). The novel mixed water-methanol cluster consists of one grail-shaped hexadecameric cluster, four dangling water and four hanging methanol molecules. The (H2O)16cluster is composed of two pairs of edge-sharing (H2O)5rings attached to one (H2O)4core with twenty hydrogen bonds. Alternatively, the (H2O)16cluster is structurally similar to a complicated hydrocarbon generated by undergoing [2+2] cycloaddition of 1,2,3,4,5,6-hexahydropentalene, which reveals the resemblance between water clusters and organic compounds.A discrete centrosymmetric (H2O)20(CH3OH)4binary cluster was confined in the cavity of a metal-ligand hybrid [Ag4(bpda)2(bpp)4·14H2O·2CH3OH]n(1) (where bpp = 1,3-bis(4-pyridyl)propane and H2bpda = 2,2'-biphenyldicarboxylic acid). The novel mixed water-methanol cluster consists of one grail-shaped hexadecameric cluster, four dangling water and four hanging methanol molecules. The (H2O)16cluster is composed of two pairs of edge-sharing (H2O)5rings attached to one (H2O)4core with twenty hydrogen bonds. Alternatively, the (H2O)16cluster is structurally similar to a complicated hydrocarbon generated by undergoing [2+2] cycloaddition of 1,2,3,4,5,6-hexahydropentalene, which reveals the resemblance between water clusters and organic compounds.

Abstract: Electrochemical behavior of (C70)2-p-tert-butylcalix [8] arene film on a glassy carbon electrode has been studied by cyclic voltammetry. Two pairs of reduction/reoxidation waves were detected in a mixed solvent of acetonitrile and water containing tetra-n-butylammonium perchlorate as the supporting electrolyte.

Constructing novel electrode materials with supernal specific capacitance and cycle stability is important for the practical applications of supercapacitors. Herein, ultrathin and highly crumpled CoP/reduced graphene oxide (rGO) nanosheet arrays are grown on nickel foam (NF) through a hydrothermal-phosphidation route. Benefitting from the synergistic effects of CoP with large specific capacity and rGO with high conductivity and ultrathin nanosheet arrays structure, CoP/rGO shows extraordinary electrochemical performance. The CoP/rGO electrode possesses a superior specific capacity of 1438.0 C g–1(3595.0 F g–1) at 1 A g–1, which is 3.43, 2.05, and 2.26 times larger than those of Co(OH)2/rGO, Co3O4/rGO, and bare CoP. In particular, the CoP/rGO nanosheet arrays show the highest specific capacities among the monometallic phosphide-based nanostructures reported so far. The CoP/rGO retains 1198.9 C g–1(2997.2 F g–1) at 10 A g–1, revealing the outstanding rate capability of 83%. Theoretical calculations reveal that rGO can adequately reduce the absorption energy of OH–on CoP, which makes CoP/rGO have strong adsorption capacity of OH–, resulting in boosting electrochemical performance. A hybrid supercapacitor of CoP/rGO/NF//AC was designed, which presents a superior energy density of 43.2 Wh kg–1at a power density of 1010.5 W kg–1. After 10 000 cycles, the CoP/rGO/NF//AC supercapacitor reveals excellent cycling durability with a capacitance retention of 89%. This work provides a new insight into the design of high-performance electrode materials by combining high capacitive metal phosphides with conductive carbon, which is of great significance for energy storage systems.

Electrochemical behavior of C60−p‐tert‐butylcalix[8]arene inclusion complex film has been studied by cyclic voltammetry. One pair of stable reduction/reoxidation peaks was obtained in a mixed solvent of acetonitrile and water (3:1 v/v) containing tetra‐n‐butylammonium perchlorate as the supporting electrolyte. The process is a two‐electron transfer reaction.