A method for solving a conditional cauchy equation on abelian groups

Sunto In questa Nota è descritto wn metodo per la determinazione delle soluzioni della seguente equazione condizionale f(x+y) f(x) + f(y) + a implica f(x + y)=f(x) + f(y) dove f:GH, a H e G ed H sono gruppi abeliani qualsiasi. Sono poi determinate esplicitamente le soluzioni nei casi G=(r), G= e G=(p).

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Lavoro svolto nell'ambito del G.N.A.F.A.-C.N.R.     

Modelling the soundscape quality of urban waterfronts by artificial neural networks

The renewal of the urban waterfronts has become a major focus of attention for politicians and decision makers in the city’s management programs. The recognition of the patterns that define the waterfronts’ identity is essential to select new strategies of intervention for the environmental recovery. In order to create adequate environments for everyday life within a sustainable development, new links between human senses, human perception and design need to be created. Within this wide approach, the landscape and the soundscape play a significant role and can become a key driving force in the implementation of the changes. New techniques have to be tested to identify the sonic and visual parameters capable to explain the specificity of a waterfront. With this purpose, an artificial neural network (ANN) was developed, and the relative importance of the input variables was evaluated. The collected database was also analysed by multiple linear regression (MLR) to compare the outcomes of both models. The urban waterfront of Naples (Italy) was chosen as case study. The results obtained show that the performance of the neural network is better than the one of the linear regression (rANN = 0.949, rMLR = 0.639). The interpretation of the relative importance method is also quite satisfactory in the ANN.     

Redox switchable ligands suitable for transition metal ions: Protonation,complexation and electrochemical properties of a ferrocene-modified tetraamine diketone and its saturated analogue

Abstract

The new ferrocene-containing water-soluble ligands 1 and 2 were synthesized and their protonation and complexation properties toward Ni^II and Cu^II studied as a function of pH, by means of potentiometric titration experiments. Electrochemical measurements were performed in aqueous solution on pure 1 and 2 and in the presence of Ni^II and Cu^II cations, in the pH range 2–12, allowing us to determine the redox potential values relative to the ferrocene oxidation in the free ligands and in their Ni^II and Cu^II complexes. 1 and 2 behave as redox switchable ligands, the former enhancing, the latter decreasing its binding ability upon oxidation of the appended ferrocene function. Besides, the Cu^II complex of ligand 1 and the Ni^II complex of ligand 2 behave as two-centre two-electron redox systems, the complexed metal cation being subject to further oxidation to M^III.     

Realizing the Promise—The Development of Research on Carbon Nanotubes

The present reflection on the development of research on carbon nanotubes (CNTs) stems from the publication of the report “Realizing the Promise of Carbon Nanotubes” by the US National Nanotechnology Initiative in 2015. The report is a critical assessment of the state‐of‐art of CNT research and highlights some unresolved issues related with this field. Starting from the results of this assessment, we carried out an analysis of the publications’ pool in CNTs and related domains, by exploiting bibliometric tools. We focused on the item of competition/collaboration between disciplines and nations, with the purpose of evaluating the position of chemistry (as a discipline) as well as the position of the main European countries and the European Union (EU) as a whole in the context of CNT research. The results of such analysis outline very clearly the interdisciplinary landscape wherein CNT research is situated and show the highly competitive place occupied by EU in the field.     

Synthesis,Structure and Catalytic Activity of NHC–AgI Carboxylate Complexes

A general synthetic route was used to prepare 15 new N‐heterocyclic carbene (NHC)–Ag^I complexes bearing anionic carboxylate ligands [Ag(NHC)(O₂CR)], including a homologous series of complexes of sterically flexible ITent ligands, which permit a systematic spectroscopic and theoretical study of the structural and electronic features of these compounds. The complexes displayed a significant ligand‐accelerated effect in the intramolecular cyclisation of propargylic amides to oxazolidines. The substrate scope is highly complementary to that previously achieved by NHC–Au and pyridyl–Ag^I complexes.     

Polymerization-Driven Photoluminescence in Alkanolamine-Based C-Dots

Carbonized polymer dots (CPDs), a peculiar type of carbon dots, show extremely high quantum yields, making them very attractive nanostructures for application in optics and biophotonics. The origin of the strong photoluminescence of CPDs resides in a complicated interplay of several radiative mechanisms. To understand the correlation between CPD processing and properties, the early stage formation of carbonized polymer dots has been studied. In the synthesis, citric acid monohydrate and 2-amino-2-(hydroxymethyl)propane-1,3-diol have been thermally degraded at 180 °C. The use of an oil bath instead of a more traditional hydrothermal reactor has allowed the CPD properties to be monitored at different reactions times. Transmission electron microscopy, time-resolved photoluminescence, nuclear magnetic resonance, infrared, and Raman spectroscopy have revealed the formation of polymeric species with amide and ester bonds. Quantum chemistry calculations have been employed to investigate the origin of CPD electronic transitions. At short reaction times, amorphous C-dots with 80 % quantum yield, have been obtained.