Search

Kagome materials serve as crucial platforms for investigating the quantum anomalous Hall effect (QAHE) due to the presence of kagome bands in their electronic structures. However, despite the theoretical predictions being proposed, kagome band material realizations have been limited. In this work, through tight-binding (TB) model analysis, by setting the nearest-neighbor hopping integrals with opposite signs, we propose a Yin–Yang kagome band structure characterized by two stable enantiomorphic kagome bands. Furthermore, we design a monolayer V3Cl6 to confirm the TB model. Three V atoms are located in different coordination environments in V3Cl6, so opposite signs of the hopping integrals between two of their orthogonal d orbitals can be achieved, which is the key to realize Yin–Yang kagome band structures. The calculated band structures obtained from first principles are consistent with those from the TB model. Additionally, we find that the two enantiomorphic flat bands in monolayer V3Cl6 possess opposite Chern number after spin–orbit coupling is considered, which can also be confirmed from symmetry index analysis. The Chern numbers as well as the topological properties can be modulated by doping hole or adjusting the magnetization directions, so the QAHE can be tuned in monolayer V3Cl6. Our results provide a practicable pathway for realizing Yin–Yang kagome band structures and achieving tunable QAHE in them. [ABSTRACT FROM AUTHOR]

Two-dimensional intrinsic magnetic topological materials that can realize device miniaturization have attracted significant attention recently based on their chiral dissipationless edge states. However, since the experimental observation of quantum anomalous Hall effect (QAHE) is still limited by low temperature, high operating temperature and large nontrivial gap are urgently needed. Here, monolayer MnAsO3 is predicted to be a room-temperature intrinsic magnetic topological material with high Chern number C = 3 based on first-principles calculations, which offers the possibility of achieving high-speed and low-energy-consumption electron transport in the future. Furthermore, the large and experimental feasible nontrivial gap up to 79.09 meV is obtained under compressive strain modulation. Moreover, the high-Chern-number topological phase transition and strain-induced spin-unlocked edge states are observed, indicating the possibility of tuning the electron transport of QAHE. All these findings suggest that monolayer MnAsO3 is a suitable and promising material for fabricating low-energy-consumption spintronics devices. [ABSTRACT FROM AUTHOR]

The exploration of valley-related physics is essential to the development and refinement of valleytronics. Here, a paradigm called chiral breathing-valley locking (CBVL) is proposed, in which two chiral "breathing" phases are completely locked to their valley indexes. Utilizing first-principles calculations, a two-dimensional (2D) kagome lattice with large spontaneous valley polarization (VP), namely, monolayer Ta3I8, is proposed to realize CBVL. There are two breathing phases with chiral symmetry in Ta3I8, and they can change to each other under some conditions. The valley indexes change between "−K" and "K" along the breathing of the two chiral symmetric phases, so CBVL can be obtained. Remarkably, the VP is up to 199.7 meV, so CBVL can cause the obvious switching of the anomalous valley Hall effect (AVHE). Additionally, a 2D Janus Kagome structure TaI4X4 is constructed to confirm experimentally the feasibility of electric field modulation on the CBVL. The built-in electric field and the breathing mode can mutually influence each other in TaI4X4, which provides a synergistic regulation of the AVHE. Our findings broaden the horizon for exploring AVHE materials and provide a platform for future valleytronic applications. [ABSTRACT FROM AUTHOR]

The combination of valleytronics and topology has great potential significance in condensed matter and material physics. Here, based on first-principles calculations, we predict a dipolar ferromagnetic semiconductor OsClBr. Benefiting from strong spin–orbit coupling and the intrinsic exchange interaction of localized d electrons, spontaneous valley polarization occurs. In addition, the tensile strain can induce topological phase transitions between ferrovalley, half-valley-metal, and valley-polarization quantum anomalous Hall (VQAH) phases, which can be attributed to the band inversion between d z 2 and d x y / d x 2 − y 2 orbitals of Os atom. Moreover, stacking-dependent topological phase transitions can be found in bilayer OsClBr, and the robustness of VQAH phase in b − 1 configuration under a wide strain range has been proved, which is greatly beneficial for the regulation of quantum states. Our work provides a potential opportunity for the preparation and application of low-power consumption electronics devices. [ABSTRACT FROM AUTHOR]

Hydrogen energy is very important as a new clean energy source to combat the growing environmental problems. In this regard, novel photocatalyst materials for water splitting have a wide range of applications. Using first principles calculations, we theoretically studied three orthorhombic group-IVB nitride halide monolayers, Hf2N2Br2, Janus HfZrN2Br2 and Janus Hf2N2ClBr. The energy, dynamic and thermal stabilities are demonstrated for all three monolayers. Using the HSE hybrid functional, the calculations reveal that they are direct band gap semiconductors with suitable band edge positions, good optical absorptions, and anisotropic carrier mobilities, which makes them promising for water splitting applications. Importantly, the photogenerated carriers provide enough driving force to trigger the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) within wide pH ranges, and then overall water splitting can be achieved spontaneously. We conclude that orthorhombic group-IVB nitride halide monolayers have potential applications in photocatalytic nanodevices. [ABSTRACT FROM AUTHOR]

The prediction and optimization of the rate of penetration (ROP) for horizontal wells are more complicated than for vertical wells, but most of the current ROP prediction studies are for vertical wells, which cannot be adapted to the complex drilling characteristics of horizontal wells. To this end, this paper proposes a data knowledge dual-driven horizontal well ROP prediction method. Firstly, the drilling characteristics of horizontal wells are analyzed, showing that the horizontal wells ROP prediction model cannot be modeled using surface measurement data; secondly, based on the analysis of horizontal well drilling characteristics, a physical model-based horizontal well ROP modeling data pre-processing method is proposed by introducing the drag and torque model. Finally, a data knowledge dual-driven horizontal well ROP prediction method is proposed in conjunction with data-driven algorithms. The proposed horizontal well ROP prediction method is applied to the A1~A4 wells in the Sichuan area. Compared with the conventional data-driven ROP prediction method, the prediction accuracy of this method is improved by 30%. The proposed method can provide a basis for the intelligent optimization and management of ROP during the drilling of horizontal wells. [ABSTRACT FROM AUTHOR]

Industrial waste gas emissions from fossil fuel over‐exploitation have aroused great attention in modern society. Recently, metal‐organic frameworks (MOFs) have been developed in the capture and catalytic conversion of industrial exhaust gases such as SO2, H2S, NOx, CO2, CO, etc. Based on these resourceful conversion applications, in this review, we summarize the crucial role of the surface, interface, and structure optimization of MOFs for performance enhancement. The main points include (1) adsorption enhancement of target molecules by surface functional modification, (2) promotion of catalytic reaction kinetics through enhanced coupling in interfaces, and (3) adaptive matching of guest molecules by structural and pore size modulation. We expect that this review will provide valuable references and illumination for the design and development of MOF and related materials with excellent exhaust gas treatment performance. [ABSTRACT FROM AUTHOR]

Background: Hypertension is considered the most important risk factor for cardiovascular diseases, but its control is poor worldwide. We aimed to assess the availability and affordability of blood pressure-lowering medicines, and the association with use of these medicines and blood pressure control in countries at varying levels of economic development. Methods: We analysed the availability, costs, and affordability of blood pressure-lowering medicines with data recorded from 626 communities in 20 countries participating in the Prospective Urban Rural Epidemiological (PURE) study. Medicines were considered available if they were present in the local pharmacy when surveyed, and affordable if their combined cost was less than 20% of the households' capacity to pay. We related information about availability and affordability to use of these medicines and blood pressure control with multilevel mixed-effects logistic regression models, and compared results for high-income, upper-middle-income, lower-middle-income, and low-income countries. Data for India are presented separately because it has a large generic pharmaceutical industry and a higher availability of medicines than other countries at the same economic level. Findings: The availability of two or more classes of blood pressure-lowering drugs was lower in low-income and middle-income countries (except for India) than in high-income countries. The proportion of communities with four drug classes available was 94% in high-income countries (108 of 115 communities), 76% in India (68 of 90), 71% in upper-middle-income countries (90 of 126), 47% in lower-middle-income countries (107 of 227), and 13% in low-income countries (nine of 68). The proportion of households unable to afford two blood pressure-lowering medicines was 31% in low-income countries (1069 of 3479 households), 9% in middle-income countries (5602 of 65 471), and less than 1% in high-income countries (44 of 10 880). Participants with known hypertension in communities that had all four drug classes available were more likely to use at least one blood pressure-lowering medicine (adjusted odds ratio [OR] 2·23, 95% CI 1·59–3·12); p

Copyright of Journal of Hospitality Marketing & Management is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The solid‐phase microwave thermal shock (SMTS) strategy is a novel method to fabricate micro‐nano composites via interface engineering. By exploiting the transient hot spot effect and arc discharge of strong microwave absorbing materials, rGO‐CuOx composites from GO‐Cu(OH)2 precursors within several 10‐s cycles are synthesized. In the composites, Cu2O nanoparticles show a narrow size distribution of 10–50 nm with metallic Cu nanoclusters uniformly distributed on the surface. The optimized sample exhibits excellent photothermal performance by coupling solar‐to‐thermal effects from phonons, free electrons, and electron acceptors. The seawater evaporation rate is 1.28 kg m‐2 h‐1 with 85.7% solar‐to‐vapor conversion efficiency under 1 sun radiation. Meanwhile, the composite evaporators are characterized by excellent anti‐salt and anti‐bacterial properties during the evaporation. The removal efficiency of Na+, Mg2+, K+, and Ca2+ is above 99.5%. These findings provide a sound basis for large‐scale desalination and purification of seawater. [ABSTRACT FROM AUTHOR]

Kagome materials serve as crucial platforms for investigating the quantum anomalous Hall effect (QAHE) due to the presence of kagome bands in their electronic structures. However, despite the theoretical predictions being proposed, kagome band material realizations have been limited. In this work, through tight-binding (TB) model analysis, by setting the nearest-neighbor hopping integrals with opposite signs, we propose a Yin–Yang kagome band structure characterized by two stable enantiomorphic kagome bands. Furthermore, we design a monolayer V3Cl6 to confirm the TB model. Three V atoms are located in different coordination environments in V3Cl6, so opposite signs of the hopping integrals between two of their orthogonal d orbitals can be achieved, which is the key to realize Yin–Yang kagome band structures. The calculated band structures obtained from first principles are consistent with those from the TB model. Additionally, we find that the two enantiomorphic flat bands in monolayer V3Cl6 possess opposite Chern number after spin–orbit coupling is considered, which can also be confirmed from symmetry index analysis. The Chern numbers as well as the topological properties can be modulated by doping hole or adjusting the magnetization directions, so the QAHE can be tuned in monolayer V3Cl6. Our results provide a practicable pathway for realizing Yin–Yang kagome band structures and achieving tunable QAHE in them. [ABSTRACT FROM AUTHOR]

The exploration of valley-related physics is essential to the development and refinement of valleytronics. Here, a paradigm called chiral breathing-valley locking (CBVL) is proposed, in which two chiral "breathing" phases are completely locked to their valley indexes. Utilizing first-principles calculations, a two-dimensional (2D) kagome lattice with large spontaneous valley polarization (VP), namely, monolayer Ta3I8, is proposed to realize CBVL. There are two breathing phases with chiral symmetry in Ta3I8, and they can change to each other under some conditions. The valley indexes change between "−K" and "K" along the breathing of the two chiral symmetric phases, so CBVL can be obtained. Remarkably, the VP is up to 199.7 meV, so CBVL can cause the obvious switching of the anomalous valley Hall effect (AVHE). Additionally, a 2D Janus Kagome structure TaI4X4 is constructed to confirm experimentally the feasibility of electric field modulation on the CBVL. The built-in electric field and the breathing mode can mutually influence each other in TaI4X4, which provides a synergistic regulation of the AVHE. Our findings broaden the horizon for exploring AVHE materials and provide a platform for future valleytronic applications. [ABSTRACT FROM AUTHOR]

Keywords: metal-organic framework; industrial waste gas; adsorption; catalysis; resources transformation EN metal-organic framework industrial waste gas adsorption catalysis resources transformation 1 1 1 06/26/23 20230601 NES 230601 The front cover summarizes crucial roles of the surface, interface, and structure optimization of MOFs for performance enhancements towards reversible capture and catalytic conversion of industrial waste gases. Metal-organic framework, industrial waste gas, adsorption, catalysis, resources transformation Cover Picture: Surface, Interface and Structure Optimization of Metal-Organic Frameworks: Towards Efficient Resourceful Conversion of Industrial Waste Gases (Chem. Rec. 6/2023). [Extracted from the article]

By the incorporation of coumarin fluorophores within the benzyldihydrazone moiety and by carefully adjusting the redox potential of the fluorophore and its excited state energy, one of the brightest Cu2+-binding sensors in aqueous media was achieved and could be used for the detection of Cu2+in living cells. [ABSTRACT FROM AUTHOR]

van der Waals heterostructures (vdWHs) can exhibit novel physical properties and a wide range of applications compared with monolayer two-dimensional (2D) materials. In this work, we investigate the electronic and optical properties of MoSTe/MoGe2N4 vdWH under two different configurations using the VASP software package based on density functional theory. The results show that Te4-MoSTe/MoGe2N4 vdWH is a semimetal, while S4-MoSTe/MoGe2N4 vdWH is a direct band gap semiconductor. Compared with the two monolayers, the absorption coefficient of MoSTe/MoGe2N4 vdWH increases significantly. In addition, the electronic structure and the absorption coefficient can be manipulated by applying biaxial strains and changing interlayer distances. These studies show that MoSTe/MoGe2N4 vdWH is an excellent candidate for high-performance optoelectronic devices. [ABSTRACT FROM AUTHOR]

The electronic structure and spin polarization properties of pentagonal structure PdSe2 doped with transition metal atoms are studied through first- principles calculations. The theoretical investigations show that the band gap of the PdSe2 monolayer decreases after introducing Cr, Mn, Fe and Co dopants. The projected densities of states show that p-d orbital couplings between the transition metal atoms and PdSe2 generate new spin nondegenerate states near the Fermi level which make the system spin polarized. The calculated magnetic moments, spin density distributions and charge transfer of the systems suggest that the spin polarization in Cr-doped PdSe2 will be the biggest. Our work shows that the properties of PdSe2 can be modified by doping transition metal atoms, which provides opportunity for the applications of PdSe2 in electronics and spintronics. [ABSTRACT FROM AUTHOR]

The electronic structure and the optical properties of Graphene/MoS2 heterostructure (GM) are studied based on density functional theory. Compared with single-layer graphene, the bandgap will be opened; however, the bandgap will be reduced significantly when compared with single-layer MoS2. Redshifts of the absorption coefficient, refractive index, and the reflectance appear in the GM system; however, blueshift is found for the energy loss spectrum. Electronic structure and optical properties of single-layer graphene and MoS2 are changed after they are combined to form the heterostructure, which broadens the extensive developments of two-dimensional materials. [ABSTRACT FROM AUTHOR]

Abstract: A system based on FRET mechanism, comprising a coumarin donor and a rhodamine acceptor, was developed for the selective and quantitative detection of metal ions. Fluorescent chemosensors RCs, linked by 1,2-diethylamine, exhibit significant fluorescence enhancement and excellent selectivity toward Cu2+. Fluorescent probes CRB and CR6G, linked by hydrazide, function as ratiometric receptors for Cu2+ chromogentically and fluorogentically in organic-aqueous media. Furthermore, the characteristic rhodamine-based fluorescence response of CRB (excitation at 550 nm) exhibits high selectivity for Hg(II). The construction of this kind of universal FRET system opens a broader prospect for future design of ratiometric fluorescent probes. [ABSTRACT FROM AUTHOR]

Prediction and synthesis of two-dimensional high transition temperature ( T C ) superconductors is an area of extensive research. Based on calculations of the electronic structures and lattice dynamics, we predict that graphene-like layered monolayer LiC 12 is a π -electrons mediated Bardeen-Cooper-Schrieffer-type superconductor. Monolayer LiC 12 is theoretically stable and expected to be synthesized experimentally. From the band structures and the phonon dispersion spectrum, it is found that the saddle point of π -bonding bands induces large density of states at the Fermi energy level. There is strongly coupled between the vibration mode in the in-plane direction of the lithium atoms and the π -electrons of carbon atoms, which induces the high- T C superconductivity in LiC 12 . The T C can reach to 41 K under an applied 10% biaxial tensile strain based on the anisotropic Eliashberg equation. Our results show that monolayer LiC 12 is a good candidate as π -electrons mediated electron-phonon coupling high- T C superconductor., (© 2023 IOP Publishing Ltd.)

With the advancement of digital economy, organizations around the world need to stretch the boundaries of their strategy, business, and knowledge to gain a competitive advantage and achieve sustainable growth. Although boundary-spanning leadership, with a set of practical tools developed by the Center for Creative Leadership (CCL), has been explored over the past 10 years, the comprehensive understanding of top management team boundary-spanning leadership has still reached no consensus. This research focuses on the concept of top management team boundary-spanning leadership (TMTBSL) and its effect on employees' innovative behavior. Study 1 comprises the concept of TMTBSL and the measurement of its development. The classical grounded theory was used to analyze biographical texts and in-depth interview data from local Chinese organizations. We developed a 5-dimension scale with14 items for TMTBSL. In Study 2, we empirically examined the impact of TMTBSL on employees' innovative behavior. The results demonstrate that TMTBSL can promote employee innovative behavior through perceived motivational climate. The theoretical and practical implications are also outlined., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Liu, Yu, Zhao and Zhang.)

The valley-polarized quantum anomalous Hall effect (VP-QAHE) in topological materials, which usually is induced by applying external manipulations, has attracted intensive attention. Here, we predict the formation and regulation of the intrinsic VP-QAHE in ferromagnetic Janus monolayer Fe 2 SSe. Spontaneous valley polarization (VP) appears without external manipulations due to the Janus structure in monolayer Fe 2 SSe. The spontaneous VP in addition to the nonzero Chern number in Fe 2 SSe confirm the intrinsic VP-QAHE. Besides, the topologically protected chiral-spin-valley locking edge states can be regulated by reversing the magnetization. Topological phase transitions between metal, half-metal, topological insulator, and ferrovalley phases can be obtained by applying biaxial strains in Fe 2 SSe, and the nontrivial band gap reaches up to 441 meV. Also, the topological phase with the VP-QAHE is robust under certain conditions. Both the intrinsic VP-QAHE and controllable topological phase transitions can be achieved in Janus monolayer Fe 2 SSe, which provides an avenue for the applications of dissipationless valleytronic devices.

Inspired by the new progress in the research field of two-dimensional valleytronics materials, we propose a new class of transition metal halides, i.e. H-ZrX 2 (X = Cl, Br, I), and investigated their valleytronics properties under the first-principles calculations. It harbors the spin-valley coupling at K and K' points in the top of valence band, in which the valley spin splitting of ZrI 2 can reach up to 115 meV. By carrying out the strain engineering, the valley spin splitting and Berry curvature can be effectively tuned. The long-sought valley polarization reaches up to 108 meV by doping Cr atom, which corresponds to the large Zeeman magnetic field of 778 T. Furthermore, the valley polarization in ZrX 2 can be lineally adjusted or flipped by manipulating the magnetization orientation of the doped magnetic atoms. All the results demonstrate the well-founded application prospects of single-layer ZrX 2 , which can be considered as great candidate for the development of valleytronics and spintronics., (© 2021 IOP Publishing Ltd.)

Two-dimensional (2D) van der Waals heterostructures (vdWHs) have attracted widespread attention in fundamental materials science and device physics. In this work, we report a novel GaTe/MoS 2 vdWH and theoretically investigate the electronic and optical properties based on first-principles calculations. GaTe/MoS 2 vdWH possesses an indirect band gap with type-II band alignment. Meanwhile, the interfacial charge transfer from MoS 2 to GaTe can effectively separate electrons and holes. Also, this vdWH shows improved visible-ultraviolet optical absorption properties compared with those of the isolated GaTe or MoS 2 monolayers. More remarkably, the biaxial strain can not only modulate the band gap but also enhance the optical performance in GaTe/MoS 2 vdWH. In particular, the tensile strain is more effective for improving the optical absorption in the visible light region. These findings indicate that GaTe/MoS 2 vdWH is a promising candidate for nanoelectronics and optoelectronic devices., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The standard treatment for Glioblastoma multiforme (GBM) is surgical resection and subsequent radiotherapy and chemotherapy. Surgical resection of GBM is typically restricted because of its invasive growth, which results in residual tumor cells including glioma stem cells (GSCs) and differentiated cells. Recurrence has been previously thought to occur as a result of these GSCs, and hypoxic microenvironment maintains the GSCs stemness also plays an important role. Summarizing traditional studies and we find many researchers ignored the influence of hypoxia on differentiated cells. We hypothesized that the residual differentiated cells may be dedifferentiated to GSC-like cells under hypoxia and play a crucial role in the rapid, high-frequency recurrence of GBM. Therefore, isolated CD133-CD15-NESTIN- cells were prepared as single-cell culture and treated with hypoxia. More than 95% of the surviving single differentiated CD133-CD15-NESTIN- cell dedifferentiated into tumorigenic CD133+CD15+NESTIN+ GSCs, and this process was regulated by hypoxia inducible factor-1α. Moreover, the serum also played an important role in this dedifferentiation. These findings challenge the traditional glioma cell heterogeneity model, cell division model and glioma malignancy development model. Our study also highlights the mechanism of GBM recurrence and the importance of anti-hypoxia therapy. In addition to GSCs, residual differentiated tumor cells also substantially contribute to treatment resistance and the rapid, high recurrence of GBM.

Background: Identification and treatment of hypertension in China remain suboptimal despite high prevalence of hypertension and increasing incidence of stroke and myocardial infarction., Objective: This study reported blood pressure levels, prevalence, awareness, treatment, and control rates of hypertension, in addition to drug treatments in China., Methods: This is a country-specific analysis of 45 108 individuals, average age 51.4 (standard deviation 9.6) (35-70) years, enrolled between 2005 and 2009, from 70 rural and 45 urban communities in 12 provinces., Results: Among 18 915 (41.9% overall population) hypertensive participants, 7866 (41.6%) were aware, 6503 (34.4%) treated but only 1545 (8.2%) controlled. Prevalence of hypertension was higher, but awareness, treatment, and control were lower in rural than urban residents. Prevalence of hypertension was highest in eastern (44.3%), intermediate in central (39.3%), and lowest in western regions (37.0%). Awareness was higher in central (44.3%) and eastern (42.4%) but lower in western regions (37.0%). Similar patterns were observed in treatment rates, 37.7% central, 35.2% eastern, and 26.7% in western regions with control rates of 8.3% in eastern, 7.6% central, and 5.3% west regions. Of 4744 participants receiving documented treatments, 37.5% received traditional combination drugs alone, 55.4% western drugs alone and 7.1% combination of traditional combination drug in addition to western drugs., Conclusion: In China, hypertension is common, and while recent studies suggest some improvements, more than half of affected individuals were unaware that they had hypertension. Rates of control remain low. National programs effective in preventing and controlling hypertension in China are urgently needed.