Review of CVD Synthesis of Graphene Muñoz, Roberto; Gómez-Aleixandre, Cristina
Chemical vapor deposition,
December 2013, Letnik:
19, Številka:
10-11-12
Journal Article
Recenzirano
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This article presents an overview of the research highlights in graphene synthesis by CVD. The growth mechanisms over transition metals and alloys (with emphasis on Cu and Cu alloys) are discussed, ...including new developments and experiments in transfer‐free graphene growth on dielectric materials. The focus is on the role of the various synthesis parameters, including the thermodynamic aspects of the chemical process, and the physical, chemical, and morphological properties of the substrate catalyst. The relationships between these parameters, and the properties of the as‐grown graphene are discussed. Some important relationships are reviewed and used to influence the fundamental parameters of, and methods for, the synthesis of high quality graphene.
A comprehensive overview of the research highlights in graphene synthesis by CVD on metals is presented. The discussion includes new developments in transfer‐free graphene growth on dielectric functional materials, and the latest exciting results in single‐crystal, large‐domain graphene synthesis. The role of the synthesis parameters, including thermodynamics, and the physical, chemical, and morphological properties of the catalyst, are also addressed.
A coordination polymer is fully exfoliated by solvent‐assisted interaction only. The soft‐delamination process results from the structure of the starting material, which shows a layered structure ...with weak layer‐to‐layer interactions and cavities with the ability to locate several solvents in an unselective way. These results represent a significant step forward towards the production of structurally designed one‐molecule thick 2D materials with tailored physico‐chemical properties.
A non‐haemadsorbing (non‐HAD) ASF virus (ASFV) genotype II, namely Lv17/WB/Rie1, was isolated from a hunted wild boar in Latvia in 2017. Domestic pigs experimentally infected with the non‐HAD ASFV ...developed a nonspecific or subclinical form of the disease. Two months later, these animals were fully protected when exposed to other domestic pigs infected with a related virulent HAD genotype II ASFV.
We introduce scanning-probe-assisted nanowire circuitry (SPANC) as a new method to fabricate electrodes for the characterization of electrical transport properties at the nanoscale. SPANC uses an ...atomic force microscope (AFM) to manipulate nanowires to create complex and highly conductive nanostructures (paths) that work as nanoelectrodes, allowing connectivity and electrical characterization of other nano-objects. The paths are formed by the spontaneous cold welding of gold nanowires upon mechanical contact, leading to an excellent contact resistance of ∼9 Ω/junction. SPANC is an easy to use and cost-effective technique that fabricates clean nanodevices. Hence, this new method can complement and/or be an alternative to other well-established methods to fabricate nanocircuits such as electron beam lithography (EBL). The circuits made by SPANC are easily reconfigurable, and their fabrication does not require the use of polymers and chemicals. In this work, we present a few examples that illustrate the capabilities of this method, allowing robust device fabrication and electrical characterization of several nano-objects with sizes down to ∼10 nm, well below the current smallest size able to be contacted in a device using the standard available technology (∼30 nm). Importantly, we also provide the first experimental determination of the sheet resistance of thin antimonene flakes.
The elastic modulus of freely suspended graphene monolayers, obtained via chemical reduction of graphene oxide, was determined through tip-induced deformation experiments. Despite their defect ...content, the single sheets exhibit an extraordinary stiffness (E = 0.25 TPa) approaching that of pristine graphene, as well as a high flexibility which enables them to bend easily in their elastic regime. Built-in tensions are found to be significantly lower compared to mechanically exfoliated graphene. The high resilience of the sheets is demonstrated by their unaltered electrical conductivity after multiple deformations. The electrical conductivity of the sheets scales inversely with the elastic modulus, pointing toward a 2-fold role of the oxygen bridges, that is, to impart a bond reinforcement while at the same time impeding the charge transport.
Precision oncology comprises the set of strategies that aim to design the best cancer treatment based on tumor biology. A recognized subset of patients with non‐small cell lung cancer (NSCLC) harbor ...actionable genomic aberrations that can benefit from targeted therapy. In lung cancer, epidermal growth factor receptor (EGFR) mutations and anaplastic lymphoma kinase (ALK) rearrangements are well characterized oncogenic drivers for which the therapeutic use of tyrosine kinase inhibitors has demonstrated improved outcomes compared with chemotherapy. Other druggable targets are also well characterized, and effective inhibitors have been developed and commercialized, leading to a paradigm shift in NSCLC treatment. Here, the authors provide a review of the oncogenic role of the most relevant molecular alterations in NSCLC and emerging treatments in this setting beyond EGFR‐driven and ALK‐driven diseases.
This is a narrative review of the most relevant molecular alterations in non–small cell lung cancer beyond EGFR‐driven and ALK‐driven disease. The oncogenic role of these molecular aberrations and targeted therapy with emerging drugs in this setting are described.
The extraordinary strength, stiffness1 and lightness of graphene have generated great expectations of its application in flexible electronics and as a mechanical reinforcement agent. However, the ...presence of lattice defects, unavoidable in sheets obtained by scalable routes, might degrade its mechanical properties2, 3. Here we report a systematic study on the elastic modulus and strength of graphene with a controlled density of defects. Counter-intuitively, the in-plane Young's modulus increases with increasing defect density up to almost twice the initial value for a vacancy content of ~0.2%. For a higher density of vacancies, the elastic modulus decreases with defect inclusions. The initial increase in Young's modulus is explained in terms of a dependence of the elastic coefficients on the momentum of flexural modes predicted for two-dimensional membranes4, 5. In contrast, the fracture strength decreases with defect density according to standard fracture continuum models. These quantitative structure-property relationships, measured in atmospheric conditions, are of fundamental and technological relevance and provide guidance for applications in which graphene mechanics represents a disruptive improvement.
Highly conductive chemically‐derived graphene can be synthesized using an efficient two‐step method starting from graphene oxide. The key strategy involves the use of a CVD process to heal defects ...contained within the monolayers, which imparts a two order of magnitude enhancement of electrical conductivity over the merely reduced samples.
Comparison of the CIELab and CIEDE2000 color difference formulas Gómez-Polo, Cristina, PhD; Muñoz, María Portillo, PhD; Lorenzo Luengo, Mari Cruz, PhD ...
The Journal of prosthetic dentistry,
2016, January 2016, 2016-Jan, 2016-01-00, 20160101, Letnik:
115, Številka:
1
Journal Article
Recenzirano
Abstract Statement of problem Many color specification systems and color differences have been proposed to improve the correlation between color measurement and visual perception. Although color ...differences can be quantified using either the CIELab formula (ΔE*ab ) or the recently introduced CIEDE2000 formula (ΔE00), which captures the perceived color difference better is unknown. Purpose The purpose of this study was to evaluate the CIELab and CIEDE2000 formulas to determine which best reflects the difference in color perception and whether color perception differs by sex. Material and methods Forty participants grouped 18 dental resin disks (color range: from 73.6 to 87.5 for L*; from −1.6 to 3.4 for a*; from 18.1 to 36.6 for b*), the only requirement being that each group was formed of disks with chromatically indistinguishable colors. Each participant was free to choose the number and composition of the groups. With the results obtained, a dissimilarity matrix was generated, and nonmetric multidimensional scaling (MDS) was applied to it to obtain the coordinates of the disks within a Euclidean space. Results The linear correlation coefficient between the interpoint distances of the MDS configuration (MDS_total sample) and the color differences with the CIELab formula (ΔE*ab ) was 0.176 ( P =.029), whereas with the CIEDE2000 formula (ΔE00) it was 0.289 ( P <.001). For the configuration obtained in the women’s group (MDS_w), the correlation between the interpoint distances and the CIELab color differences was 0.230 ( P =.004), and the CIEDE2000 color difference was 0.328 ( P <.001). For the configuration obtained in the men’s group (MDS_m), the color differences calculated with both formulas reflected the perceived differences more poorly. Conclusions Within the limitations of this study, the CIEDE2000 formula reflected the color differences perceived by the human eye better than the CIELab formula (ΔE*ab ). In addition, women were confirmed to be more sensitive than men to color differences.
Young speakers and women have been identified as leaders of language change in the English language. However, sociolinguistic studies addressing grammatical variation according to the age and gender ...of speakers are infrequent in world Englishes mainly due to the dearth of corpora with explicit detailed metadata. In this paper we explore the effect of these two factors on language innovation and creativity as represented in the International Corpus of English (ICE). For that purpose, we have selected two high‐frequency grammatical phenomena: (i) the expression of perfect meaning, which exhibits variability between different forms; and (ii) relative clauses, with variation in the use of relativizers. A preliminary analysis of the variable age shows that young speakers behave differently as regards both the expression of perfect meaning and the choice of relativizers. With this study we hope to contribute to this still small but growing body of sociolinguistic research on grammatical variation in world Englishes.
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