Crossover from Linear Chains to a Honeycomb Network for the Nucleation of Hexagonal Boron Nitride Grown on the Ni(111) Surface

Hexagonal boron nitride (h-BN) holds great potential for applications due to its unique electronic properties and high chemical stability. Practical applications of h-BN, however, rely on the growth of large-scale, high-quality samples, for which an adequate understanding of the growth mechanism is critically important. In this work, we study the nucleation of h-BN on the Ni(111) surface by density functional theoretical calculations. Our results reveal a novel structural crossover from a chain-like BN cluster to an sp2-bonded honeycomb network at the very beginning of growth. This structural transition occurs in clusters with a critical size of 8 BN pairs, beyond which the honeycomb structure is energetically preferred. After that, the growth proceeds in a downhill manner till a full coverage of h-BN on the Ni surface, driven by continuous reduction in energy of the BN clusters with feeding BN pairs. The critical size can be controlled by tuning chemical potentials. Our results also present that lattice defects, such as 4- and 5-membered rings, are higher in energy and, thus, disfavored in the growth. This work not only explains the formation of high-quality BN sheets but also opens a way to rationally control the synthesis of h-BN by selecting appropriate substrates. The atomistic understandings of nucleation of h-BN are extendable to other two-dimensional materials

BN-Embedded Graphene with a Ubiquitous Gap Opening

The electronic structures of BN-embedded graphene (BNG) were theoretically studied. A nonzero gap was found to exist in BNG regardless of the edge structures (zigzag/armchair) and the symmetries of the superlattice and BN quantum dots (QDs). The size of the gap is mainly determined by the width of the carbon wall between neighboring BN QDs. It is insensitive to the size of BN QDs, and thus obeys a universal scaling law. This significant and stable energy gap renders BNG as a promising way to control the electronic properties of graphene. The comparison with graphene antidot lattices and nanoribbons was also provided

Soil indexes in study area.

Soil indexes in study area.</p

The WUE of different plant life forms.

(1) the WUE of herbs, shrubs and trees; (2) the WUE of evergreen plants and deciduous plants.</p

The WUE of 32 plant species surveyed.

Different labels (a-l) are significantly different between the WUE of plant species (P Fig 2.</p

The mean, SD (standard deviation) and CV (coefficient of variation) of the WUE of the sampled species.

The mean, SD (standard deviation) and CV (coefficient of variation) of the WUE of the sampled species.</p

The WUE of the plant species surveyed in each habitat.

A, B, C and D represent residential green spaces, street green spaces, park green spaces and the riverside wetland respectively. Plant species are represented by numbers on abscissa axis: 1-Verbena officinalis L., 2-Cirsium setosum (Willd.) Besser ex M.Bieb., 3-Picea asperata Mast., 4-Dianthus chinensis L., 5-Ulmus pumila ‘Jinye’, 6-Rumex acetosa L., 7-Rosa chinensis Jacq. var. spontanea (Rehd. et Wils.) Yü et Ku, 8-Tamarix ramosissima Lbd., 9-Iris tectorum Maxim., 10-Prunus × cisterna ‘Pissardii’, 11-Zoysia tenuifolia, 12-Sedum spectabile, 13-Amygdalus triloba (Lindl.) Ricker, 14-Juniperus formosana Hayata, 15-E. crus-galli, 16-Lavandula angustifolia Mill., 17-Prunus Cerasifera Ehrh. f. atropurpurea (Jacq.) Rehd., 18-Trifolium repens L., 19-Iris lacteal Pall. var. chinensis (Fisch.) Koidz., 20-Rosa xanthina Lindl., 21-Euonymus phellomanus Loes., 22-Hosta ventricosa (Salisb.) Stearn, 23-Salix matsudana Koidz., 24-Lythrum salicaria L., 25-Typha orientalis C. Presl, 26-Platycladus orientalis (L.) Franco, 27-Rudbeckia hirta L., 28-Artemisia mongolica (Fisch. ex Besser) Fisch. ex Nakai, 29-Salix babylonica L., 30-Forsythia viridissima Lindl., 31-Coreopsis lanceolata L., 32-Syringa oblata Lindl.</p

Map of sampling plots collected from Guyuan.

(1) The map of China; (2) the map of Guyuan City; and the locations of the sampling plots are shown in (3) and (4). The circles: the sampling plots of residential green spaces; the asterisks: the sampling plots of street green spaces; the diamond: the sampling plots of park green spaces; the squares: the sampling plots of the riverside wetland.</p

The WUE conditions of the four habitats.

A, B, C and D represent residential green spaces, street green spaces, park green spaces and the riverside wetland respectively.</p

Isotope-based water-use efficiency of major greening plants in a sponge city in northern China - Fig 4

The WUE of the same species in A—B and in B—C. A, B, and C represent residential green spaces, street green spaces and park green spaces respectively. The names of the species corresponding to the species numbers are shown in the notes of Fig 2.</p