scholarly journals A Comparative Study of the ZnO Growth on Graphene and Graphene Oxide: The Role of the Initial Oxidation State of Carbon

2020 ◽  
Vol 6 (2) ◽  
pp. 41
Author(s):  
Miguel Angel Gomez-Alvarez ◽  
Carlos Morales ◽  
Javier Méndez ◽  
Adolfo del Campo ◽  
Fernando J. Urbanos ◽  
...  

The role of the oxidation state of carbon on the early stages of growth of metal oxides was studied for the particular case of ZnO deposition on graphene and graphene oxide on SiO2 (G/SiO2 and GO/SiO2, respectively) substrates. The growth was carried out by thermal evaporation of metallic Zn under an oxygen atmosphere at room temperature. This technique permits quasi-equilibrium conditions during the oxide growth, allowing the characterization of the fundamental interaction between ZnO and the graphene-based substrates. Although in both cases ZnO follows a Volmer–Weber growth mode controlled by nucleation at defects, the details are different. In the case of the GO/SiO2 substrate, the nucleation process acts as a bottleneck, limiting the coverage of the complete surface and allowing the growth of very large ZnO structures in comparison to G/SiO2. Moreover, by studying the Zn-LMM Auger spectra, it is shown how the initial nature of the substrate influences the composition of the ZnO deposit during the very early stages of growth in terms of Zn/O atomic ratio. These results are compared to those previously reported regarding ZnO growth on graphite and graphene on Cu (G/Cu). This comparison allows us to understand the role of different characteristics of graphene-based substrates in terms of number of defects, oxidation state, graphene support substrate and number of graphene layers.

2018 ◽  
Vol 6 (3) ◽  
pp. 1801689 ◽  
Author(s):  
Carlos Morales ◽  
Andrés Black ◽  
Fernando J. Urbanos ◽  
Daniel Granados ◽  
Javier Méndez ◽  
...  

Author(s):  
George G. Cocks ◽  
Louis Leibovitz ◽  
DoSuk D. Lee

Our understanding of the structure and the formation of inorganic minerals in the bivalve shells has been considerably advanced by the use of electron microscope. However, very little is known about the ultrastructure of valves in the larval stage of the oysters. The present study examines the developmental changes which occur between the time of conception to the early stages of Dissoconch in the Crassostrea virginica(Gmelin), focusing on the initial deposition of inorganic crystals by the oysters.The spawning was induced by elevating the temperature of the seawater where the adult oysters were conditioned. The eggs and sperm were collected separately, then immediately mixed for the fertilizations to occur. Fertilized animals were kept in the incubator where various stages of development were stopped and observed. The detailed analysis of the early stages of growth showed that CaCO3 crystals(aragonite), with orthorhombic crystal structure, are deposited as early as gastrula stage(Figuresla-b). The next stage in development, the prodissoconch, revealed that the crystal orientation is in the form of spherulites.


Author(s):  
Lucia Dacome

Chapter 7 furthers the analysis of the role of anatomical models as cultural currencies capable of transferring value. It does so by expanding the investigation of the early stages of anatomical modelling to include a new setting. In particular, it follows the journey of the Palermitan anatomist and modeller Giuseppe Salerno and his anatomical ‘skeleton’—a specimen that represented the body’s complex web of blood vessels and was presented as the result of anatomical injections. Although Salerno was headed towards Bologna, a major centre of anatomical modelling, he ended his journey in Naples after the nobleman Raimondo di Sangro purchased the skeleton for his own cabinet of curiosities. This chapter considers the creation and viewing of an anatomical display in di Sangro’s Neapolitan Palace from a comparative perspective that highlights how geography and locality played an important part in shaping the culture of mid-eighteenth-century anatomical modelling.


2011 ◽  
Vol 46 (1) ◽  
pp. 32-55 ◽  
Author(s):  
Michael Holmes ◽  
Simon Lightfoot

AbstractThis article looks at the role of the Party of European Socialists (PES) in its attempts to shape social democratic parties in Central and Eastern Europe (CEE) towards a West European norm. It discusses how existing views in the academic literature on the role of transnational parties are inadequate. We argue that the PES did not play a key role in encouraging the establishment and development of parties in the CEE states from the 2004 enlargement in the early stages of accession. We contend that the overall influence of party federations has been limited, and that these limitations were as much in evidence before enlargement took place as they were afterwards.


2019 ◽  
Vol 13 ◽  
pp. 04020
Author(s):  
Giovan Battista Mattii ◽  
Eleonora Cataldo ◽  
Linda Salvi ◽  
Sofia Sbraci ◽  
Francesca Paoli ◽  
...  

In the early stages of planting, the shelter can provide for young vines protection against damage of various kinds. Despite their widespread use, few surveys have been devoted to the study of innovative shelter types and the possible influence of these protections on the physiology and development of plants. In the present experiment, which took place in 2017 in a Tuscan winery, the effects of vine protections by the company OSO (Prato) on single leaf gas exchanges and on the shoot growth in the first year of planting were studied. Three types of shelters with a circular section (completely perforated, partially perforated and closed) have been compared with the traditional full-wall shelters with square section. During the growing season, sprout growth measures, leaf area, leaf gas exchanges and water potential were carried out on the young vines. At the end of the season, shoots were sampled to measure the dry matter accumulated during the season. Among the shelters taken into consideration, it emerges that the completely perforated type guarantees the best development, with differences that are almost always significant for most of the measured parameters with traditional shelters. On the contrary, the closed typology has led to a reduction in growth, in gas exchanges and in water potential. In conclusion, the type completely perforated could constitute a valid alternative to the traditional one because, besides being a useful means for the protection of the vine, it could benefit the development of the root system in the early stages of growth.


2013 ◽  
Vol 103 (7) ◽  
pp. 073305 ◽  
Author(s):  
Xiao-Chen Jiang ◽  
Yan-Qing Li ◽  
Yan-Hong Deng ◽  
Qi-Qi Zhuo ◽  
Shuit-Tong Lee ◽  
...  

2016 ◽  
Vol 21 (3) ◽  
pp. 279-286 ◽  
Author(s):  
Fatemeh Nasibi ◽  
Khosrow Manouchehri Kalantari ◽  
Roya Zanganeh ◽  
Ghasem Mohammadinejad ◽  
Hakimeh Oloumi

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