Search results for " Aluminium"
showing 10 items of 42 documents
Porous Aluminium Oxide Coating for the Development of Spectroscopic Ellipsometry Based Biosensor: Evaluation of Human Serum Albumin Adsorption
2020
An electrochemically synthesised porous anodic aluminium oxide (pAAO) layer has been analysed by means of spectroscopic ellipsometry. The determined thickness of the formed pAAO layer obtained from spectroscopic ellipsometry measurements and modelling was 322.75 ±
Revisiting the metallothionein genes polymorphisms and the risk of oral squamous cell carcinoma in a Brazilian population
2020
Background Metallothioneins (MTs) gene polymorphisms have been associated with the ability of free radical scavenging and detoxification of heavy metals leading to cancer development. Our aim was to revisit, in a Brazilian population, single-nucleotide polymorphisms (SNPs) of the MT gene family previously associated with oral squamous cell carcinoma (OSCC). Material and Methods A case-control investigation with 28 OSCC patients and 45 controls was conducted, using conventional risk factors (tobacco use and alcohol consumption) as covariates. SNPs genotyping for rs8052334 (MT1B), rs964372 (MT1B), and rs1610216 (MT2A) was performed by PCR-RFLP, and SNPs for rs11076161 (MT1A) were analyzed by …
Growth and optical characterization of indirect-gap AlxGa1−xAs alloys
1999
Nonintentionally doped AlxGa1−xAs layers with 0.38 x 0.84 were grown on (100) GaAs substrates by liquid phase epitaxy (LPE) under near-equilibrium conditions. The crystalline quality of the samples was studied by photoluminescence at 2 K and room temperature Raman spectroscopy. The peculiar behavior in the photoluminescence intensities of the indirect bound exciton line and the donor–acceptor pair transition is explained from the evolution of the silicon donor binding energy according to the aluminum composition. It was also possible to observe the excitonic transition corresponding to the AlxGa1−xAs/GaAs interface, despite the disorder and other factors which are normally involved when gro…
Influence of process parameters for thixotropic alloys
2007
With reference to a metallic alloy, the attribute thixotropic is utilized to indicate the behaviour of it in the semi-solid state when its microstructure consists of spheroids in a liquid matrix. Such alloys are characterized by very low values of viscosity under shearing stress in the semi-solid state, while after solidification they show relevant mechanical properties. Actually a structural change from a dendritic structure to a globular one, with the globular grains finely dispersed in a liquid matrix, is observed after particular thermo-mechanical treatments. In the present paper the authors present the results of a wide experimental campaign on the AA 7075 aluminium alloy that shows a …
Effect of fertilisation on the changes of soil pH and exchangeable aluminium content in soil
2015
W pracy oceniono stopień zakwaszenia gleby oraz zawartość glinu wymiennego w zależności od rodzaju zastosowanego nawozu mineralnego oraz jego dawki. Badania prowadzono w oparciu o doświadczenie wazonowe z jęczmieniem jarym odmiany browarniczej Propino. Uzyskane wyniki wskazują, że największe zakwaszenie oraz największe zawartości glinu wymiennego stwierdza się w warunkach stosowania nawożenia w kombinacji NPK wraz z saletrą amonową. Zastosowany w różnych dawkach siarczan wapnia dwuwodny nie wpłynął na zmianę odczynu gleby, a odnotowana zawartość glinu wymiennego była niższa niż w kombinacji NPK wraz z saletrą amonową.
Bimolecular reduction of 9-alkyl-3-nitrocarbazoles
2007
AbstractReduction of 9-alkyl-3-nitrocarbazoles (Ia–Ie) with lithium aluminium hydride gave corresponding 9,9′-dialkyl-3,3′-azocarbazoles (IIa–IIe) in moderate yield. By the action of zinc dust in alcohol and aqueous alkali on I or II, 5,13-dialkyldiindolo[3,2-a,d]phenazines (IIIa–IIId) were obtained. Parent compounds, viz. 3,3′-azocarbazole (IIf) and diindolo[3,2-a,d]phenazine (IIIf) could not be obtained in these ways. Compound IIf was obtained in Vorländer reaction and IIIf by thermal decomposition of 3-azidocarbazole. Formation of IIIa–IIId is explained as a result of ortho-benzidine rearrangement of hypothetical 9,9′-dialkyl-3,3′-hydrazocarbazoles.
Alkylumlagerungen und acidolyse der ethylidenbrücken bei der synthese von ethylidendiphenolen
1990
For the synthesis of symmetrical and unsymmetrical ethylidenediphenols the corresponding hydroxyphenylethanols (1a–c) were prepared by hydrogenation of hydroxyphenyl methyl ketones with hydrogen/Raney nickle or with lithium aluminium hydride. Condensations of the hydroxyphenylethanols with different phenols under the usual acidic conditions gave products formally resulting form transalkylations. Only the reaction of 1-(3-bromo-2-hydroxy-5-methylphenyl)ethanol (1c) with p-cresol gave the expected product 2d with 82% yield. Experiments with ethylidenediphenols showed that with acids in presence or absence of phenols cleavage and recondensations take place leading to products of formal transal…
Macro-micro relationship in nanostructured functional composites
2012
This paper examines the results of the characterization of two functional composites: Poly(methyl methacrylate) (PMMA)-Ce:YAG (yttrium aluminium garnet doped with cerium) and PMMA-cobalt hexacyanoferrate (CoHCF). The composites were prepared as possible emitters in the fields of lighting thermal sensors. The prepared composites were char- acterized using transmission electron microscopy (TEM), nuclear magnetic resonance (NMR) spectroscopy, thermogravi- metric analysis (TGA), differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) analyses to study the correlation between micro and macro characteristics. We found that the molecular interactions of the two different fill…
Porosity of anodic alumina membranes from electrochemical measurements
2005
A procedure based on the high-field mechanism of the growth of anodic oxides was developed in order to evaluate the morphological features of porous layers. Since the thickness of the barrier film, separating the porous layer from the metal, does not change during the steady-state growth of an anodic porous layer, the rate of displacement of the metal-oxide interface to the metal direction must be equal to the rate of displacement of the pore base to the oxide direction. As a consequence, porosity can be expressed in terms of the ratio i diss/i ion, where i diss is the dissolution current density at the pore base, and i ion is the ionic current density at the metal-oxide interface. Pore dia…
Enhancement of Hydrolysis through the Formation of Mixed Heterometal Species: Al3+/CH3Sn3+ Mixtures
2013
ABSTRACT: The hydrolysis of mixed-metal cations (Al3+/CH3Sn3+) was studied in aqueous solutions of NaNO3, at I = 1.00 ± 0.05 mol·dm−3 and T = 298.15 K, by potentiometric technique. Several hydrolytic mixed species are formed in this mixed system, namely, Alp(CH3Sn)q(OH)r with (p, q, r) = (1, 1, 4), (1, 1, 5), (1, 1, 6), (2, 1, 4), (1, 2, 5), (1, 4, 11), (1, 3, 8), and (7, 6, 32). The stability of these species, expressed by the equilibrium: pAl3+ + qCH3Sn3+ + rOH− = Alp(CH3Sn)q(OH)r 3(p+q)−r, βpqr OH, can be modeled by the empirical relationship: log βpqr OH = −3.34 + 2.67p + 9.23(q + r). By using the equilibrium constant Xpqr relative to the formation reaction: pAl(p+q)(OH)r + q(CH3Sn)(p+q…