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The significance of graphene and its two-dimensional (2D) analogous inorganic layered materials especially as hexagonal boron nitride (h-BN) and molybdenum disulphide (MoS 2 ) for “clean energy” applications became apparent over the last few years due to their extraordinary properties. In this review article we study the current progress and selected challenges in the syntheses of graphene, h-BN and MoS 2 including energy storage applications as supercapacitors and batteries. Various substrates/catalysts (metals/insulator/semiconducting) have been used to obtain graphene, h-BN and MoS 2 using different kinds of precursors. The most widespread methods for synthesis of graphene, h-BN and MoS 2 layers are chemical vapor deposition (CVD), plasma-enhanced CVD, hydro/solvothermal methods, liquid phase exfoliation, physical methods etc. Current research has shown that graphene, h-BN and MoS 2 layered materials modified with metal oxide can have an insightful influence on the performance of energy storage devices as supercapacitors and batteries. This review article also contains the discussion on the opportunities and perspectives of these materials (graphene, h-BN and MoS 2 ) in the energy storage fields. We expect that this written review article including recent research on energy storage will help in generating new insights for further development and practical applications of graphene, h-BN and MoS 2 layers based materials.

Indium–tin oxide nanowires were deposited by excimer laser ablation onto catalyst-free oxidized silicon substrates at a low temperature of 500 °C in a nitrogen atmosphere. The nanowires have branches with spheres at the tips, indicating a vapor–liquid–solid (VLS) growth. The deposition time and pressure have a strong influence on the areal density and length of the nanowires. At the earlier stages of growth, lower pressures promote a larger number of nucleation centers. With the increase in deposition time, both the number and length of the wires increase up to an areal density of about 70 wires/μm². After this point all the material arriving at the substrate is used for lengthening the existing wires and their branches. The nanowires present the single-crystalline cubic bixbyite structure of indium oxide, oriented in the 〈100〉 direction. These structures have potential applications in electrical and optical nanoscale devices.

In this work, graphite nanobelts-based films as a promising material for applications in flexible blood pulse sensors with low power consumption are studied. A modified Langmuir Blodgett method used here for the sensor fabrication, is a reliable, simple and scalable technique allowing for controlled deposition of conducting films with desired electrical properties. The nanobelts, deposited over oxidized silicon or onto flexible polydimethylsiloxane substrates, were morphologically and electrically characterized. The response of the sensors to blood pulses measured on wrists and necks of two different persons (a male and a female) and the ways of the sensor response optimization are discussed.

Purpose – The purpose of this paper is to compare the results from mechanical testing with measurements of surface-dependent properties performed on polyamide parts made by selective laser sintering (SLS) to assess a possible correlation between them. Design/methodology/approach – Fabrication of Nylon 12 (Duraform PA®) samples using different laser power levels and their characterization by tensile testing, roughness and Raman scattering measurements. Findings – Among the surface methods investigated, the results from Raman spectroscopy are the best ones, but methods dependent on surface analysis are not really suitable as indicators of the mechanical properties. The correlation coefficients for linear fitting obtained when the normalized results of mechanical properties are plotted against the surface properties are too low. Furthermore, the ambiguity between surface and mechanical data makes it impossible to use these surface properties for prediction purposes in the industrial environment. Originality/value – Quantitative evaluation and correlation between mechanical properties and surface properties of SLS-made samples.

Purpose - This paper aims to demonstrate the functionalization of polyamide parts made by selective laser sintering (SLS) for application as substrates for chemical analysis by surface-enhanced Raman scattering (SERS). Design/methodology/approach - Fabrication of Nylon 12 (Duraform PA®) samples using two laser power levels and deposition of a layer of gold-coated zinc oxide nanostructures. Performance of these substrates in the detection of a known compound was tested by Raman spectroscopy. Findings - The hydrothermal synthesis proved to be a good method for functionalizing the surface of polyamide parts made by the SLS process. By varying the synthesis temperature, ZnO nanoparticles and nanorods attached to the sample surfaces could be obtained. The degree of sample sintering had an effect on the growth of the nanostructures. The gold-coated functionalized surfaces enhanced the Raman signal from crystal violet by more than three orders of magnitude. ZnO nanorods grown on well-sintered SLS parts showed the best performance from the set of samples tested in this work. Originality/value - ZnO nanostructures were grown directly on untreated surfaces of SLS-made polyamide. These substrates were used for chemical analysis by SERS.

Purpose – This paper aims to demonstrate the functionalization of polyamide parts made by selective laser sintering (SLS) for application as substrates for chemical analysis by surface-enhanced Raman scattering (SERS). Design/methodology/approach – Fabrication of Nylon 12 (Duraform PA®) samples using two laser power levels and deposition of a layer of gold-coated zinc oxide nanostructures. Performance of these substrates in the detection of a known compound was tested by Raman spectroscopy. Findings – The hydrothermal synthesis proved to be a good method for functionalizing the surface of polyamide parts made by the SLS process. By varying the synthesis temperature, ZnO nanoparticles and nanorods attached to the sample surfaces could be obtained. The degree of sample sintering had an effect on the growth of the nanostructures. The gold-coated functionalized surfaces enhanced the Raman signal from crystal violet by more than three orders of magnitude. ZnO nanorods grown on well-sintered SLS parts showed the best performance from the set of samples tested in this work. Originality/value – ZnO nanostructures were grown directly on untreated surfaces of SLS-made polyamide. These substrates were used for chemical analysis by SERS.

Purpose – The purpose of this paper is to characterize polyamide parts prepared by the SLS process using techniques that are dependent on surface properties and compare the results to density measurements in order to assess which technique better reflects the degree of densification achieved using different laser power levels. Design/methodology/approach – Fabrication of Nylon 12 (Duraform PA) samples and their characterization by apparent density measurements, perfilometry, Raman spectroscopy, scanning electron microscopy, specific surface area and contact angle measurements. Findings – Methods dependent on surface analysis are not suitable indicators of the degree of sample densification. Among the surface methods, the results from Raman spectroscopy are the ones with the best performance. Incipient sintering of the superficial layers and raw material powder on the surface, inherent to the parts made by the SLS process, strongly interfere with the characterization. Originality/value – Quantitative comparison of a number of surface probing methods for monitoring densification of SLS parts. Characterization of sample surfaces with and without raw material powder.

The work presented here compares two groups of three- and four-year-old children who differ in their school entrance age and consequently in the social expectations of what they should know at these particular ages. The comparison was made in order to assess the effect of children's counting ability on their ability to reason about number. An experiment was designed to make sure that children who succeeded were basing their answers only on the operation performed. The experiment included a set size with more items in it than any of the children would supposedly be able to count. Also, some of the tasks combined addition and subtraction with lengthening and shortening and homogeneous sets were used to avoid the possibility of an answer being based on the presence or absence of a specific item. Three possible outcomes were predicted and the results obtained were analysed in the light of these. The results support the conclusion that young children may reason about number even without having represented it and that children's counting ability does not necessarily underlie their capacity to identify number-relevant operations but rather that the ability to make number-based judgements develops independently from the knowledge of counting. Le travail présenté ici a permis de comparer deux groupes d'enfants de 3 et 4 ans, ayant commencé leur scolarité à des âges différents et qui, par conséquent différent aussi par les attentes sociales concernant leurs connaissances. La comparaison a été faite de façon à estimer, chez les enfants, l'influence de la capacité de compter sur leur capacité de raisonner sur les nombres. Une expérience a été réalisée pour s'assurer que les réussites des enfants sont uniquement dues à l'opération réalisée. Dans cette expérience un des ensembles à dénombrer comportait un nombre d'élément excédant les capacités de dénombrement des enfants de cet âge. En outre, les tâches utilisées combinaient addition et soustraction avec augmentation et diminution et, pour éviter que la réponse repose sur la présence ou l'absence de certains éléments, on a utilisé des ensembles homogènes; Les résultats obtenus ont été analysées fonction de trois hypothèses initiales. On peut conclure que de petits enfants peuvent raisonner sur nombre même s'ils ne savent pas représenter. Leur capacité de comptage n'est pas forcément à l'origine de leur capacité d'identifier des opérations numériques applicables; la capacité de produire des jugements sur le nombre se développe indépendamment de la connaissance du processus de comptage.