Search results for "interfaces"
showing 10 items of 1258 documents
Hellinger-Reissner variational principle for stress gradient elastic bodies with embedded coherent interfaces
2017
An Hellinger-Reissner (H-R) variational principle is proposed for stress gradient elasticity material models. Stress gradient elasticity is an emerging branch of non-simple constitutive elastic models where the infinitesimal strain tensor is linearly related to the Cauchy stress tensor and to its Laplacian. The H-R principle here proposed is particularized for a solid composed by several sub-domains connected by coherent interfaces, that is interfaces across the which both displacement and traction vectors are continuous. In view of possible stress-based finite element applications, a reduced form of the H-R principle is also proposed in which the field linear momentum balance equations are…
Direct chemical grafted curcumin on halloysite nanotubes as dual-responsive prodrug for pharmacological applications
2016
Covalently functionalized halloysite nanotubes (HNTs) were successfully employed as dual-responsive nanocarriers for curcumin (Cur). Particularly, we synthesized HNT-Cur prodrug with a controlled curcumin release on dependence of both intracellular glutathione (GSH) and pH conditions. In order to obtain HNT-Cur produgs, halloysite was firstly functionalized with cysteamine through disulphide linkage. Afterwards, curcumin molecules were chemically conjugated to the amino end groups of halloysite via Schiff's base formation. The successful functionalization of halloysite was proved by thermogravimetric analysis, FT-IR spectroscopy, dynamic light scattering and scanning electron microscopy. Ex…
A preliminary investigation assessing the basic digital capabilities of minimally verbal children on the autism spectrum with intellectual disability
2020
Purpose Children with Autism Spectrum Disorder (ASD) can demonstrate a preference for using digital technologies which can represent a relative strength within the autism community. Such a strength would have implications for digitally mediated interventions and support for autism. However, research to date has not developed a methodology for assessing the capabilities of minimally verbal children on the autism spectrum with intellectual disability (ID) to use digital technology. Design/methodology/approach Six minimally verbal children with ASD and ID undertook an accessible assessment that identified what capabilities for interacting with a digital tablet device they could and could not …
Al2O3 ALD films grown using TMA + rare isotope 2H216O and 1H218O precursors
2021
Abstract In this work hydrogen and oxygen migration and exchange reactions in the atomic layer deposited (ALD) Al2O3 thin films were studied together with hydrogen incorporation by varying deposition parameters. Al2O3 films deposited at low temperatures can contain more than 20 at.% of hydrogen. Both higher temperature and longer purge length decrease the hydrogen and carbon concentrations significantly. In order to track the hydrogen and oxygen movement in the films, heavy water (2 H 2 16 O) and oxygen-18 enriched water (1 H 2 18 O) were used as precursors in combination with trimethylaluminium (TMA). Different isotopes of the same element were quantified by means of time-of-flight elastic…
Investigation of surface properties of lunar regolith: Part I
2007
This paper describes an initial investigation of the surface properties of three lunar soil samples from the Apollo 11, 12 and 16 missions, respectively. We report on density measurements using a helium pycnometer, adsorption isotherms of krypton applied for the determination of specific surface area of the samples and gravimetric measurement of the isotherms of water, heptane and octane. Electron-microscopic photographs are described and discussed.
Mo(CO)6 dissociation on Cu(111) stimulated by a Scanning Tunneling Microscope
2013
Abstract The surface of Cu(111) was exposed to molybdenum hexacarbonyl Mo(CO)6 with monolayer coverage at temperature 160 K and studied by a Scanning Tunneling Microscope. The monolayer structure has a hexagonal arrangement and forms a (√7 × √7) R19 superlattice on the copper (111) plane. Upon repeated scanning the monolayer is transformed into a (1 × 2) superstructure with 3-fold oriented domains. The domains of (1 × 2) superstructure can change orientation under scanning according to 3-fold surface symmetry. From analysis of the domain mobility, it follows that CO groups of carbonyl fragments are organized in the (1 × 2) superstructure conditioning the domain reorientation. The observed s…
Atmospheric pressure plasma polymerisation of metalloporphyrins containing mesoporous membranes for gas sensing applications
2013
Abstract Metalloporphyrins are embedded in an organosilicon matrix by an easily up-scalable atmospheric pressure dielectric barrier discharge method. The integrity of the metalloporphyrins, followed by UV–visible spectroscopy, is successfully preserved and their aggregation prevented. The single molecule properties, rather than the bulk ones, are thus enhanced. Exposure to triethylamine, which reaches the metalloporphyrins through the pores of the organosilicon membrane, led to a shift in the absorption spectrum and confirms the gas sensing potential of such coatings.
Optimization of ZnO:Al/Ag/ZnO:Al structures for ultra-thin high-performance transparent conductive electrodes
2012
Al-doped ZnO (AZO)/Ag/AZO multilayer coatings (50-70 nm thick) were grown at room temperature on glass substrates with different silver layer thickness, from 3 to 19 nm, by using radio frequency magnetron sputtering. Thermal stability of the compositional, optical and electrical properties of the AZO/Ag/AZO structures were investigated up to 400 °C and as a function of Ag film thickness. An AZO film as thin as 20 nm is an excellent barrier to Ag diffusion. The inclusion of 9.5 nm thin silver layer within the transparent conductive oxide (TCO) material leads to a maximum enhancement of the electro-optical characteristics. The excellent measured properties of low resistance, high transmittanc…
In-situ annealing characterization of atomic-layer-deposited Al2O3 in N2, H2 and vacuum atmospheres
2019
Tarkista embargo, kun artikkeli julkaistu. Atomic-layer-deposited Al 2 O 3 films can be used for passivation, protective, and functional purposes in electronic devices. However, as-deposited, amorphous alumina is susceptible to chemical attack and corrosion during manufacturing and field-use. On the contrary, crystalline Al 2 O 3 is resistant against aggressive chemical treatments and corrosion. Here, high-temperature treatments in N 2 , H 2 , and vacuum were used to crystallize alumina which exhibited different crystalline phases. The annealing process was monitored continuously in situ by measuring the film temperature and surface reflectance to understand the crystallization kinetics. Ex…
Oxygen-deficient Co3O4 submicron porous sphere films as highly active supsercapacitor electrodes
2021
Abstract Herein, we report Co3O4 films with different content of oxygen vacancies and shapes of particles for supercapacitor electrodes. Under the similar area ratio of OII peak in the XPS spectrum of oxygen elements, the specific capacitance of electrode films with hollow spongy-like particles (963 F/g under a scan rate of 5 mV/s) is 1.6 times higher than that of the electrodes with solid irregular particles (596 F/g), indicating the effect of particle shapes on electrochemical properties. The films composed of submicron porous spheres and containing highest content of oxygen vacancies exhibited the specific capacitances as high as 1700 F/g under the scan rate of 5 mV/s. By contrast, after…