61 research outputs found
Single-crystal two-dimensional material epitaxy on tailored non-single-crystal substrates
No full text© 2022, The Author(s).The use of single-crystal substrates as templates for the epitaxial growth of single-crystal overlayers has been a primary principle of materials epitaxy for more than 70 years. Here we report our finding that, though counterintuitive, single-crystal 2D materials can be epitaxially grown on twinned crystals. By establishing a geometric principle to describe 2D materials alignment on high-index surfaces, we show that 2D material islands grown on the two sides of a twin boundary can be well aligned. To validate this prediction, wafer-scale Cu foils with abundant twin boundaries were synthesized, and on the surfaces of these polycrystalline Cu foils, we have successfully grown wafer-scale single-crystal graphene and hexagonal boron nitride films. In addition, to greatly increasing the availability of large area high-quality 2D single crystals, our discovery also extends the fundamental understanding of materials epitaxy.11Nsciescopu
A semantic approach to patch-based procedural generation of urban road networks
No full textA road network is one of the core elements of urban environments, strongly defining their layout. Procedural modeling has been increasingly used to create such road networks. However, many procedural methods are complex and difficult to master by non-experts, often have a limited and hard-to-control expressive range, and require a variety of specialized input data to generate a complex road network. To mitigate this, some methods proposed to use stochastic data on road patches extracted from example maps to design a road network following a given urban style. We propose a novel patch-based method that uses the semantics of individual patches to help guiding the procedural generation. Our approach combines the advantages of patch-based generation with those of conventional parametric methods. Due to the intuitive character of semantic parameters and tags, our approach provides for an easy customization of fictive road network creation, allowing a user to easily define various types of road network styles, containing only the desired features and structures of real-world road networks.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Computer Graphics and Visualisatio
Constraints on Ore Genesis from Trace Ore Mineralogy: A New Occurrence of Kupčíkite and Paděraite from the Zhibula Cu Skarn Deposit, Southern Tibet
No full textMineral assemblages containing Cu-Bi sulfosalts, Bi chalcogenides, and Ag-(Au) tellurides have been identified in the mid-Miocene Zhibula Cu skarn deposit, Gangdese Belt, southern Tibet. Different mineral assemblages from three locations in the deposit, including proximal massive garnet skarn, proximal retrogressed pyroxene-dominant skarn in contact with marble, and distal banded garnet–pyroxene skarn hosted in marble, are studied to constrain the evolution of the mineralization. Hypogene bornite contains elevated Bi (mean 6.73 wt.%) and co-exists in proximal andradite skarn with a second bornite with far lower Bi content, carrollite, Au-Ag tellurides (hessite, petzite), and wittichenite. This assemblage indicates formation at relatively high temperatures (>400 ◦C) and high f S2 and f Te2 during prograde-stage mineralization. Assemblages of Bi sulfosalts (wittichenite, aikinite, kupčíkite, and paděraite) and bismuth chalcogenides (e.g., tetradymite) in proximal pyroxene skarn are also indicative of formation at relatively high temperatures, but at relatively lower f Te2 and f S2 conditions. Within the reduced distal skarn (chalcopyrite–pyrrhotite-bearing) in marble, cobalt, and nickel occur as discrete minerals: cobaltite, melonite and cobaltic pentlandite. The trace ore mineral signature of the Zhibula skarn and the distributions of precious and critical trace elements such as Ag, Au, Co, Te, Se, and Bi support an evolving magmatic–hydrothermal system in which different parts of the deposit each define ore formation at distinct local physicochemical conditions. This is the first report of kupčíkite and paděraite from a Chinese location. Their compositions are comparable to other occurrences, but conspicuously, they do not form nanoscale intergrowths with one another.Jing Xu, Cristiana Liana Ciobanu, Nigel John Cook, Shen Gao, Taiping Zhao, and Jichen Jian
Systematic analysis of measurement variability in lung cancer with multidetector computed tomography
No full textObjective: To systematically analyze the nature of measurement variability in lung cancer with multidetector computed tomography (CT) scans.
Methods: Multidetector CT scans of 67 lung cancer patients were analyzed. Unidimensional (Response Evaluation Criteria in Solid Tumor criteria), bidimensional (World Health Organization criteria), and volumetric measurements were performed independently by ten radiologists and were repeated after at least 5 months. Repeatability and reproducibility measurement variations were estimated by analyzing reliability, agreement, variation coefficient, and misclassification statistically. The relationship of measurement variability with various sources was also analyzed.
Results: Analyses of 69 lung tumors with an average size of 1.1–12.1 cm (mean 4.3 cm) indicated that volumetric technique had the minimum measurement variability compared to the unidimensional or bidimensional technique. Tumor characteristics (object effect) could be the primary factor to influence measurement variability while the effect of raters (subjective effect) was faint. Segmentation and size in tumor characteristics were associated with measurement variability, and some mathematical function was established between the volumetric variability and tumor size.
Conclusion: Volumetric technique has the minimum variability in measuring lung cancer, and measurement variability is associated with tumor size by nonlinear mathematical function
Seeded growth of large single-crystal copper foils with high-index facets
No full textThe production of large single-crystal metal foils with various facet indices has long been a pursuit in materials science owing to their potential applications in crystal epitaxy, catalysis, electronics and thermal engineering(1-5). For a given metal, there are only three sets of low-index facets ({100}, {110} and {111}). In comparison, high-index facets are in principle infinite and could afford richer surface structures and properties. However, the controlled preparation of single-crystal foils with high-index facets is challenging, because they are neither thermodynamically(6,7) nor kinetically(3) favourable compared to low-index facets(6-18). Here we report a seeded growth technique for building a library of single-crystal copper foils with sizes of about 30 x 20 square centimetres and more than 30 kinds of facet. A mild pre-oxidation of polycrystalline copper foils, followed by annealing in a reducing atmosphere, leads to the growth of high-index copper facets that cover almost the entire foil and have the potential of growing to lengths of several metres. The creation of oxide surface layers on our foils means that surface energy minimization is not a key determinant of facet selection for growth, as is usually the case. Instead, facet selection is dictated randomly by the facet of the largest grain (irrespective of its surface energy), which consumes smaller grains and eliminates grain boundaries. Our high-index foils can be used as seeds for the growth of other Cu foils along either the in-plane or the out-of-plane direction. We show that this technique is also applicable to the growth of high-index single-crystal nickel foils, and we explore the possibility of using our high-index copper foils as substrates for the epitaxial growth of two-dimensional materials. Other applications are expected in selective catalysis, low-impedance electrical conduction and heat dissipation
A process-driven content-oriented integration framework for knowledge management systems
No full textThe design of ultrasonic - electromagnetic detecting circuit and application on partial discharge
No full textThe immune effect of intrathymic inoculation and whole body irradiation on production of xenoantibody in a pig-to-monkey heart transplantation model
No full textA Green Load Balancing Algorithm for Dynamic Spatial-Temporal Traffic Distribution in HetNets
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