Search results for "visual_art"

Solid proton conductors as room-temperature gas sensors

1993

Ammonia-exchanged ceramic samples of beta alumina have been obtained from plasma-dispersed powders. The ionic conductivity is slightly affected by ion exchange, but the surface conductivity for the amonia-exchanged sample drastically changes in the presence of the water and ammonia vapours. The ammonia-doped xerogel of antimonic acid hydrate in the form of a thick film has been tested as a potentiometric ammonia sensor.

Evaluation of Silver Ion Bioavailability from Silver Doped Hydroxyapatite

2014

Thein vitrobehavior of silver doped hydroxyapatite (HAp/Ag) prepared by two wet precipitation routes were studied in water and simulated body fluid (SBF). In order to evaluate the silver ion bioavailability from HAp/Ag, the samples were soaked in SBF or water and kept at 37°C for fixed periods of time up to one year. After fixed periods of time, analyses of SBF and water solutions were performed and silver ion concentration within the solutions determined. According to silver release data from dense and porous HAp/Ag ceramic scaffolds, release rate of silver ions were reduced in water as the ion exchange there was slower compared to SBF solution. X-ray diffraction and scanning electron micr…

Ultrathin metal oxidation for vacuum monitoring device applications

2011

The oxide growth on thin metal films at room temperature has been investigated in terms of resistance change during oxidation. These data have been interpreted using the extended Cabrera–Mott theory of oxidation by Boggio. The resulting oxide thickness as well as the oxidation kinetics was found to depend on pressure. According to this dependence, oxidation of ultrathin metal films can be applied for monitoring the vacuum quality inside an evacuated environment. The performance of aluminum and copper sensing layers are compared with respect to sensor lifetime and response. Furthermore, the theoretically evaluated and resistively measured oxide thicknesses are verified by TEM studies.

Dielectric properties of PMN+2%Li 2 O at low frequencies

2012

The reported study is focused on effects of the admixture of lithium (2% Li2O) on the low-frequency dielectric response in lead magnesium niobate ceramics over the 100 -300 K range of temperature. The obtained results reveal an essential thermal broadening of the e′(ν) spectra specific to relaxor ferroelectrics. Dispersion Δe′ = e′1Hz-e′1kHz and values of e′′(ν) in lead magnesium niobate ceramics containing Li are well described by the Cole-Cole equation at temperatures below the e′(T) maximum. Based on the analysis of the experimental data admixture of lithium is suggested to promote formation of domains in lead magnesium niobate ceramics (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Thermodynamic control over energy dissipation modes in dual-network hydrogels based on metal-ligand coordination.

2020

Modern polymeric hydrogels use reversible bonds to mimic biological functionalities. However, true biological materials benefit from several supramolecular elements and deliver multiple functions at the same time. To approach similar creation and control of multiple different functional elements in a synthetic soft material, we develop a model dual-network hydrogel in which multiple energy dissipating modes are formed by metal–ligand coordination and regulated by their association thermodynamics. This idea is realized by using linear and tetra-arm poly(ethylene glycol) (PEG) precursors with complementary reactive end groups. The former also carries terpyridine ligands on both ends, which fo…

Metal enhanced fluorescence in rare earth doped plasmonic core–shell nanoparticles

2013

International audience; We theoretically and numerically investigate metal enhanced fluorescence of plasmonic core–shell nanoparticles doped with rare earth (RE) ions. Particle shape and size are engineered to maximize the average enhancement factor (AEF) of the overall doped shell. We show that the highest enhancement (11 in the visible and 7 in the near-infrared) is achieved by tuning either the dipolar or the quadrupolar particle resonance to the rare earth ion's excitation wavelength. Additionally, the calculated AEFs are compared to experimental data reported in the literature, obtained in similar conditions (plasmon mediated enhancement) or when a metal–RE energy transfer mechanism is…

Machining of Steel with Advanced Ceramic Cutting-Tools

1995

Synthesis and Characterization of SiC/MC/C Ceramics (M = Ti, Zr, Hf) Starting from Totally Non-oxidic Precursors

2002

The reaction of poly(dimethylsilane) (PDMS) and poly(dimethylcarbosilane) (PCS) with bis(cyclopentadienyl)M dichloride Cp2MCl2 (M ) Ti, Zr, Hf) complexes has been used as a new route to obtain ceramic materials based on SiC-containing M. The reaction is completed at a relatively low temperature, 900 °C, yielding the corresponding amorphous SiC/MC ceramics which have been characterized by means of 29 Si MAS NMR. These amorphous materials have been treated at higher temperatures, 1350 °C, under a purified argon atmosphere, yielding partially crystallized products which have been studied by X-ray powder diffraction and 29 Si MAS NMR. The effect of the composition of the mixture of precursors is

Solvothermal synthesis derived Co-Ga codoped ZnO diluted magnetic degenerated semiconductor nanocrystals

2018

Authors kindly acknowledge to the Estonian Research Council ( PUT1096 , IUT2-25 , PUT735 ), the Estonian Centre of Excellence in Research project “Advanced materials and high-technology devices for sustainable energetics, sensorics and nanoelectronics (TK141), and the financial support of HZB. We are grateful to the staff of BESSY II for the assistance and co-operation during the synchrotron-based measurements.

Comparative In Vitro Study of the Bond Strength of Composite to Carbon Fiber Versus Ceramic to Cobalt–Chromium Alloys Frameworks for Fixed Dental Pro…

2020

Purpose: The aim of this comparative in vitro study was to assess the bond strength and mechanical failure of carbon-fiber-reinforced composites against cobalt&ndash