in this paper we will prove that if $l$ is a continuous symmetric n-linear form on a hilbert spaceand $widehat{l}$ is the associated continuous n-homogeneous polynomial, then $||l||=||widehat{l}||$.for the proof we are using a classical generalized  inequality due to s. bernstein for entire functions of exponential type. furthermore we study the case that if x is a banach space then we have tha...

In an aqueous electrolyte under anodic polarization, most of the conductive polymers could undergo overoxidation due to hydroxyl radicals formed during water oxidation. Regarding poly(3,4-ethylenedioxythiophene) (PEDOT) only a few reports studied its overoxidation. this paper, we propose facile and rapid strategy prepare ultrathin (15 nm), pinhole-free non-conductive overoxidized PEDOT film by ...

Here, we report development of the galvanostatic Fourier transform electrochemical impedance spectroscopy (FTEIS), which monitors impedance of electrochemical reactions activated by current steps. We first derive relevant relations for potential change upon application of a step current, obtain impedances theoretically from the relations by simulation, and verify them with experimental results....

Pure Ti and 85%Ti-15%Zr alloy were sintered in a heat induction high frequency furnace. The corrosion behaviour of simulated body fluid (SBF) was studied. work achieved using different techniques as the cyclic polarization (PCP), impedance spectroscopy (EIS), change potentiostatic current with time (PCT) experiments. morphology surfaces Ti-Zr after being corroded SBF for 72 investigated by scan...

Bipolar plates in proton exchange membrane fuel cells (PEMFCs) are confronted by the dilemma of low contact resistance and high corrosion resistance; this study aimed to simultaneously satisfy these dimensions a harsh environment. Using thick multilayer coatings can improve resistance, but would be largely compromised. To address challenge, we propose compatible tantalum/titanium-based on 316L ...

The formation of tin dendritic nanostructures by electrolysis from the alkaline electrolyte has been investigated. Morphology and structure Sn dendrites produced applying both potentiostatic galvanostatic regimes are characterized SEM XRD, respectively. Depending on applied cathodic potentials, three types were obtained: (a) needle-like spear-like, (b) fern-like, (c) stem-like dendrites. very b...

Twelve single chambered, air-cathode Tubular Microbial Fuel Cells (TMFCs) have been filled up with fruit and vegetable residues. The anodes were realized by means of a carbon fiber brush, while the cathodes were realized through a graphite-based porous ceramic disk with Nafion membranes (117 Dupont). The performances in terms of polarization curves and power production were assessed according t...

The effects of pH and chloride concentration on the electrochemical corrosion of copper in aqueous sodium chloride (NaCl) media were studied at the micro scale using a microcapillary droplet cell and at the macro scale using a conventional large scale cell. Using an experimental design strategy, electrochemical response surface models of copper versus pH and NaCl concentration were constructed ...