Explore the vast range of titles available.

Reduced dimensionality and interlayer coupling in van der Waals materials gives rise to fundamentally different electronic1, optical2 and many-body quantum3–5 properties in monolayers compared with the bulk. This layer-dependence permits the discovery of novel material properties in the monolayer regime. Ferromagnetic order in two-dimensional materials is a coveted property that would allow fundamental studies of spin behaviour in low dimensions and enable new spintronics applications6–8. Recent studies have shown that for the bulk-ferromagnetic layered materials CrI3 (ref. 9) and Cr2Ge2Te6 (ref. 10), ferromagnetic order is maintained down to the ultrathin limit at low temperatures. Contrary to these observations, we report the emergence of strong ferromagnetic ordering for monolayer VSe2, a material that is paramagnetic in the bulk11,12. Importantly, the ferromagnetic ordering with a large magnetic moment persists to above room temperature, making VSe2 an attractive material for van der Waals spintronics applications.

Substituting carbon with silicon in organic molecules and materials has long been an attractive way to modify their electronic structure and properties. Silicon-doped graphene-based materials are known to exhibit exotic properties, yet conjugated organic materials with atomically precise Si substitution have remained difficult to prepare. Here we present the on-surface synthesis of one- and two-dimensional covalent organic frameworks whose backbones contain 1,4-disilabenzene (C4Si2) linkers. Silicon atoms were first deposited on a Au(111) surface, forming a AuSix film on annealing. The subsequent deposition and annealing of a bromo-substituted polyaromatic hydrocarbon precursor (triphenylene or pyrene) on this surface led to the formation of the C4Si2-bridged networks, which were characterized by a combination of high-resolution scanning tunnelling microscopy and photoelectron spectroscopy supported by density functional theory calculations. Each Si in a hexagonal C4Si2 ring was found to be covalently linked to one terminal Br atom. For the linear structure obtained with the pyrene-based precursor, the C4Si2 rings were converted into C4Si pentagonal siloles by further annealing.Incorporating silicon into organic molecules and materials leads to interesting changes in electronic structure and properties; silabenzenes are attractive species for this purpose, but their high reactivity in solution poses challenges. Now, 1D and 2D covalent organic frameworks featuring disilabenzene rings (C4Si2) as linkers have been prepared by reacting silicon atoms and polyaromatic hydrocarbon precursors on a Au(111) surface.

La investigación sobre el paisaje lingüístico urbano se ha extendido por todo el mundo con distintos enfoques y desde diversas perspectivas. En el presente trabajo se expone una breve introducción sobre el desarrollo de la teoría del paisaje lingüístico y su relación con la Sociolingüística. El estudio se sitúa en una ciudad china bajo el contexto de la expansión del coronavirus para poder observar la influencia de las actualidades sociales en el paisaje lingüístico urbano. Mediante los análisis sincrónicos y diacrónicos de los signos acerca de la pandemia, se ponen de manifiesto las nuevas modalidades que obtienen, el desarrollo y aplicación de las nuevas tecnologías en la sociedad y las medidas tomadas por el gobierno chino frente a la emergencia sanitaria. Apoyada en estos descubrimientos, se llega la conclusión de que el paisaje lingüístico se vincula estrechamente a la situación social actual y puede funcionar como un indicador de ella.

To better promote the research and development of regional crop yield simulations, we review related research on regional crop yield simulations over the past ten years, summarize the research progress on regional crop yield simulations at home and abroad from the three aspects of crop growth models, remote sensing technology, and data assimilation technology, and propose three future development directions for regional crop yield simulations: (1) Based on the agronomic mechanism of crop yield estimation, it is necessary to fully consider crop growth characteristics and yield formation mechanisms. (2) With respect to the remote sensing mechanism of crop yield estimation, we can consider combining radar stereo lateral view measurement technology to determine crop characteristics and remote sensing information. (3) From the perspective of combining agronomy and remote sensing, the crop yield spatiotemporal simulation assimilation algorithm should be optimized, and the yield simulation unit should be extended. It is expected that these considerations can provide new ideas for regional crop yield simulations with high accuracy, a large scale, and full coverage.

La investigación sobre el paisaje lingüístico urbano se ha extendido por todo el mundo con distintos enfoques y desde diversas perspectivas. En el presente trabajo se expone una breve introducción sobre el desarrollo de la teoría del paisaje lingüístico y su relación con la Sociolingüística. El estudio se sitúa en una ciudad china bajo el contexto de la expansión del coronavirus para poder observar la influencia de la actualidad social en el paisaje lingüístico urbano. Mediante los análisis sincrónicos y diacrónicos de los signos acerca de la pandemia, se ponen de manifiesto las nuevas modalidades que obtienen, el desarrollo y aplicación de las nuevas tecnologías en la sociedad y las medidas tomadas por el gobierno chino frente a la emergencia sanitaria. Apoyada en estos descubrimientos, se llega a la conclusión de que el paisaje lingüístico se vincula estrechamente a la situación social actual y puede funcionar como un indicador de ella.

A length-scale insensitive degradation function is applied to extend the cracks during hydraulic fracturing under stress boundary conditions in this study. The phase field method is an effective modeling technique that has great potential for use in hydraulic fracturing. Nonetheless, current hydraulic fracturing research is still concentrated on small scales. The phase field model employs a degradation function that is insensitive to length scale, allowing for the decoupling of the phase field length scale from the physical length scale. This facilitates the simulation of hydraulic fracturing crack extensions in larger structures with a consistent mesh density. The correctness of the phase field method is verified firstly by comparing with the experimental results, and the accuracy and efficiency of the proposed method are further verified through a series of numerical calculations.

Material line defects are one-dimensional structures but the search and proof of electron behaviour consistent with the reduced dimension of such defects has been so far unsuccessful. Here we show using angle resolved photoemission spectroscopy that twin-grain boundaries in the layered semiconductor MoSe 2 exhibit parabolic metallic bands. The one-dimensional nature is evident from a charge density wave transition, whose periodicity is given by k F / π , consistent with scanning tunnelling microscopy and angle resolved photoemission measurements. Most importantly, we provide evidence for spin- and charge-separation, the hallmark of one-dimensional quantum liquids. Our studies show that the spectral line splits into distinctive spinon and holon excitations whose dispersions exactly follow the energy-momentum dependence calculated by a Hubbard model with suitable finite-range interactions. Our results also imply that quantum wires and junctions can be isolated in line defects of other transition metal dichalcogenides, which may enable quantum transport measurements and devices. Line defects are 1D structures often embedded within 2D materials. Here, the authors use angle resolved photoemission spectroscopy to unveil the 1D nature of electron behaviour in such defects in atomically thin MoS 2 , providing evidence for spin- and charge-separation.

Christian, especially Protestant, identity is often framed through the lens of belief, particularly belief understood as an interior orientation. Through an examination of the non-denominational Protestant group, the ‘Little Flock’, founded by Watchman Nee in the early 20th century, we trace enduring aspects of Little Flock theology in contemporary Chinese Protestant practice. In particular, we attend to conceptions of and debates surrounding belief and how to determine the quality of one’s faith—whether or not one might be considered not just a Christian, but a ‘good’ one.

As an important part of the urban ecosystem, the value of green spaces (GS) has become increasingly prominent. However, the interaction effect of GS characteristics are still not clear enough. This study explores the premium effect of different types of GS on housing prices (HP) in Beijing. The results show that all types of GS have a significant premium impact on HP, among which there are obvious distance and area thresholds for park GS. The distance range of municipal parks for premium effect is within 2000 m and, the closer to a community, the higher the value. In contrast, community-level parks only have a premium effect within 1500 m, and the most obvious distance is 500–1000 m away from the community. The area of parks has the greatest impact on HP when it is 20–50 ha, and municipal parks larger than 300 ha or community parks smaller than 2 ha do not produce a premium effect. Furthermore, GS surrounding and within communities can serve as substitutes for community-level parks, while municipal parks are irreplaceable and can synergistically influence HP increases with all types of GS. The study offers new findings on the influencing thresholds and interactive effects of GS, providing decision-making guidance for urban construction.

This study proposes an uncertainty quantification method based on deep neural networks and Catmull–Clark subdivision surfaces for vibroacoustic problems. The deep neural networks are utilized as a surrogate model to efficiently generate samples for stochastic analysis. The training data are obtained from numerical simulation by coupling the isogeometric finite element method and the isogeometric boundary element method. In the simulation, the geometric models are constructed with Catmull–Clark subdivision surfaces, and meantime, the physical fields are discretized with the same spline functions as used in geometric modelling. Multiple deep neural networks are trained to predict the sound pressure response for various parameters with different numbers and dimensions in vibroacoustic problems. Numerical examples are provided to demonstrate the effectiveness of the proposed method.