Printing image based on metasurface has attracted enormous research interests due to its subwavelength resolution, full‐color printing, and durable properties. Based on the spatially multiplexed ...pixels, the printing image using metasurface can be switched optically by altering the optical parameters, such as polarization and incident wavelength. However, such multiplexed pixel design has several problems, including the cross‐talk among different wavelengths, limitation to linear polarizations, and incapability for incident‐angle control. Here, a general method for pixel design, called the coherent pixel, which can overcome the problems and be used for multiple printing‐image switching controlled by arbitrary optical parameters (arbitrary incident angle, polarization, and wavelength) is proposed. Based on this coherent pixel, metasurface devices with novel functionalities can be realized, such as incident‐angle controlled and arbitrary polarization‐controlled printing images, which are not feasible with previous conventional pixel design method. The suitability and superiority of the coherent pixel for encryption application is also discussed. Such printing‐image switching controlled with arbitrary optical parameters should pave the way for various applications, including various functional switchable optical devices, image displays, and information encryption.
A coherent pixel design method is implemented for metasurface printing image switching under arbitrary optical conditions with different combinations of incident angle, polarization, and wavelength of light. Such a design not only stimulates metasurface devices with novel functionalities, such as incident‐angle controlled and helicity‐controlled printing images, but also enables encryption applications with improved security.
Heavy metal pollution has pervaded many parts of the world, especially in developing countries. The purpose of this study was to determine the concentrations and health risks of heavy metals in urban ...soils around an electronics manufacturing site in the Hubei Province of China. Soils samples were collected from commercial, roadside, farmland, and residential areas around the electronics manufacturing facility. A total of 136 topsoil samples were collected, and these samples were analyzed for Cr, Cu, Zn, As, Cd, Ni, and Pb. The geoaccumulation index (Igeo), pollution index (PI), and potential ecological risk index (PER) were calculated to assess the soil pollution levels. The hazard index (HI) was used to assess the human health risks posed by the presence of heavy metals. The total concentrations of the seven congeners (∑metals) ranged from 3738.86 to 5173.25mgkg−1, and the concentrations were highest in the commercial area followed (in decreasing order) by the roadside, farmland, and residential areas. The HI for children and adults descended in the order of Cr>As>Pb>Cd>Cu>Ni>Zn. The carcinogenic risks of two metals, namely, Cr and As, for children and adults were higher than 10−4, and children faced greater health risks.
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•Metal contamination was detected in soils near an electronics manufacturing facility.•Chromium, zinc, and lead were the most abundant metals detected.•Risks assessment results indicate that these soils may pose health risks.
Two are better than one: A mixed‐solvent method for liquid exfoliation of MoS2, WS2, and BN nanosheets is presented. Although ethanol and water are both poor solvents for this process, ethanol/water ...mixtures of appropriate composition, which can be predicted on the basis of Hansen solubility parameters, result in efficient exfoliation (see schematic) to give highly stable suspensions.
Development of non-noble-metal catalysts for hydrogen evolution reaction (HER) with both excellent activity and robust stability has remained a key challenge in the past decades. Herein, for the ...first time, N-doped carbon-wrapped cobalt nanoparticles supported on N-doped graphene nanosheets were prepared by a facile solvothermal procedure and subsequent calcination at controlled temperatures. The electrocatalytic activity for HER was examined in 0.5 M H2SO4. Electrochemical measurements showed a small overpotential of only −49 mV with a Tafel slope of 79.3 mV/dec. Theoretical calculations based on density functional theory showed that the catalytically active sites were due to carbon atoms promoted by the entrapped cobalt nanoparticles. The results may offer a new methodology for the preparation of effective catalysts for water splitting technology.
Cyanobacteria are photosynthetic prokaryotes that inhabit diverse aquatic and terrestrial environments. However, the evolutionary mechanisms involved in the cyanobacterial habitat adaptation remain ...poorly understood. Here, based on phylogenetic and comparative genomic analyses of 650 cyanobacterial genomes, we investigated the genetic basis of cyanobacterial habitat adaptation (marine, freshwater, and terrestrial). We show: (1) the expansion of gene families is a common strategy whereby terrestrial cyanobacteria cope with fluctuating environments, whereas the genomes of many marine strains have undergone contraction to adapt to nutrient-poor conditions. (2) Hundreds of genes are strongly associated with specific habitats. Genes that are differentially abundant in genomes of marine, freshwater, and terrestrial cyanobacteria were found to be involved in light sensing and absorption, chemotaxis, nutrient transporters, responses to osmotic stress, etc., indicating the importance of these genes in the survival and adaptation of organisms in specific habitats. (3) A substantial fraction of genes that facilitate the adaptation of Cyanobacteria to specific habitats are contributed by horizontal gene transfer, and such genetic exchanges are more frequent in terrestrial cyanobacteria. Collectively, our results further our understandings of the adaptations of Cyanobacteria to different environments, highlighting the importance of ecological constraints imposed by the environment in shaping the evolution of Cyanobacteria.
Millimeter‐scale 3D superlattice arrays composed of dense, regular, and vertically aligned gold nanorods are fabricated by evaporative self‐assembly. The regular organization of the gold nanorods ...into a macroscopic superlattice enables the production of a plasmonic substrate with excellent sensitivity and reproducibility, as well as reliability in surface‐enhanced Raman scattering. The work bridges the gap between nanoscale materials and macroscopic applications.
Non-cognitive skills Zhou, Kai
European journal of education,
December 2017, Letnik:
52, Številka:
4
Journal Article
Recenzirano
Skills are widely considered as key elements that contribute to the sustainable development of nations and the well-being of individuals. Given the increasing interests in the international ...comparisons of skills for informing educational policy, it is necessary to understand the definitions, measurement, and development of key skills. Using literature from economics, sociology, and psychology, this article focuses on non-cognitive skills that have a positive effect on life outcomes and can be better developed through education and training. Three non-cognitive skills – grit, self-control and social skills are illustrated and thoroughly reviewed here. Although some progress has been made in developing and measuring non-cognitive skills, there is currently no systematic global measure. Several factors hinder the global monitoring of non-cognitive skills and inhibits effective non-cognitive skills assessment across countries. These include a lack of solid evidence showing which soft skills predict academic and workforce outcomes and how does the strength of this relationship differ by situation.
A 2D black phosphorus/platinum heterostructure (Pt/BP) is developed as a highly efficient photocatalyst for solar‐driven chemical reactions. The heterostructure, synthesized by depositing BP ...nanosheets with ultrasmall (≈1.1 nm) Pt nanoparticles, shows strong Pt–P interactions and excellent stability. The Pt/BP heterostructure exhibits obvious P‐type semiconducting characteristics and efficient absorption of solar energy extending into the infrared region. Furthermore, during light illumination, accelerated charge separation is observed from Pt/BP as manifested by the ultrafast electron migration (0.11 ps) detected by a femtosecond pump‐probe microscopic optical system as well as efficient electron accumulation on Pt revealed by in situ X‐ray photoelectron spectroscopy. These unique properties result in remarkable performance of Pt/BP in typical hydrogenation and oxidation reactions under simulated solar light illumination, and its efficiency is much higher than that of other common Pt catalysts and even much superior to that of conventional thermal catalysis. The 2D Pt/BP heterostructure has enormous potential in photochemical reactions involving solar light and the results of this study provide insights into the design of next‐generation high‐efficiency photocatalysts.
A 2D black phosphorus/platinum heterostructure (Pt/BP) is developed as a highly efficient photocatalyst. The Pt/BP exhibits a broad adsorption range (>1800 nm), ultrafast electron migration (0.11 ps), and efficient electron accumulation on Pt. These unique properties result in remarkable performance of Pt/BP in solar‐driven chemical reactions and the efficiency is superior to that of conventional thermal catalysis.
Graphene functionalized with photo‐active units has become one of the most exciting topics of research in the last few years, which remarkably sustains and expands the graphene boom. The rise of ...photo‐active graphene in photonics and optoelectronics is evidenced by a spate of recent reports on topics ranging from photodetectors, photovoltaics, and optoelectronics to photocatalysis. For these applications, the fabrication of photo‐active graphene through appropriate chemical functionalization strategies is essential as pristine graphene has zero bandgap and only weak absorption of photons. Written from the chemists' point of view, up‐to‐date chemical functionalization of graphene with various small organic molecules, conjugated polymers, rare‐earth components, and inorganic semiconductors is reviewed. Particular attention is paid to the development of graphene functionalized with light‐harvesting moieties, including materials synthesis, characterization, energy/charge‐transfer processes, and applications in photovoltaics. Challenges currently faced by researchers and future perspectives in this field are also discussed.
Combining the unique electrical and mechanic properties of graphene with the excellent optical properties of various photo‐active moieties, functionalized graphene has true potential for photodetectors, optoelectronics, photovoltaics, and photocatalysis.
In this study, a general and effective phosphorization strategy is successfully demonstrated to enhance supercapacitor performance of various transition metals oxide or hydroxide, such as Ni(OH)2, ...Co(OH)2, MnO2, and Fe2O3. For example, a 3D networked Ni2P nanosheets array via a facile phosphorization reaction of Ni(OH)2 nanosheets is grown on the surface of a Ni foam. The Ni foam‐supported Ni2P nanosheet (Ni2P NS/NF) electrode shows a remarkable specific capacitance of 2141 F g−1 at a scan rate of 50 mV s−1 and remains as high as 1109 F g−1 even at the current density of 83.3 A g−1. The specific capacitance is much larger than those of Ni(OH)2 NS/NF (747 F g−1 at 50 mV s−1). Furthermore, the electrode retains a high specific capacitance of 1437 F g−1 even after 5000 cycles at a current density of 10 A g−1, in sharp contrast with only 403 F g−1 of Ni(OH)2 NS/NF at the same current density. The similar enhanced performance is observed for Ni2P powder, which eliminates the influence of nickel foam. The enhanced supercapacitor performances are attributed to the 3D porous nanosheets network, enhanced conductivity, and two active components of Ni2+ and Pδ− with rich valences of Ni2P.
Ultrahigh‐performance pseudocapacitor electrodes are prepared with a general and effective phosphorization strategy to enhance supercapacitor performance of various transition metals oxide or hydroxide. The Ni foam supported Ni2P nanosheets array electrode shows a remarkable specific capacitance of more than 3000 F g−1, much larger than the corresponding Ni(OH)2 nanosheets array before phosphorization.
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