Search results for "Vapor phase"
showing 10 items of 12 documents
Vapor-phase introduction of alkyltin compounds in atomic absorption spectrophotometry
1990
Abstract Different systems for the introduction of alkyltin compounds in atomic absorption spectrophotometry using the vapor-phase introduction approach have been compared. Samples and standards were introduced in both quartz cell and flame atomizer using a vertical and a horizontal reactor. The better sensitivity was obtained with the quartz cell and the horizontal reactor.
Direct determination of ethanol and methanol in liquid samples by means of vapor phase-Fourier transform infrared spectroscopy
1997
Abstract A FTIR procedure is proposed for the direct determination of methanol and ethanol in liquid samples, such as alcoholic beverages and eau-de-cologne, based on vapor generation from small injected volumes of untreated samples into a heated Pyrex glass reactor in which, at a temperature of 80°C, ethanol and methanol are volatilized and introduced into a long-path IR gas cell by means of a N2 carrier flow. The IR spectra obtained present two characteristic ethanol bands (1050 and 880 cm−1) and a single characteristic methanol band (1030 cm−1). The measurement of the area of the transient recording obtained for the wavenumber range between 1025–950 and 950–820 cm−1 allows us the determi…
Nonazeotropy in the System Methyl Ethanoate + 1,2-Epoxybutane
1997
New vapor−liquid equilibrium data for the binary system methyl ethanoate + 1,2-epoxybutane are reported at 35 and 101.3 kPa and at 298.15 K. It is shown that no azeotropes are present in the system, in disagreement with data reported by others who claim that two azeotropes are present at 298.15 K. We claim that previously reported data are in error because of impurities in the reagents and experimental errors. According to our results, the system methyl ethanoate + 1,2-epoxybutane behaves like a regular solution and its vapor phase can be considered practically ideal so that it cannot fulfill the necessary conditions for multiple azeotropy. The data were satisfactorily correlated using the …
Vapor Phase Deposited Single Junction and Tandem Perovskite Solar Cells.
2019
Crystal growth of ZnO micro and nanostructures by PVT on c-sapphire and amorphous quartz substrates
2010
Abstract ZnO micro and nanostructures in the form of tripods, grains, arrows and wires have been grown at temperatures as low as 500–300 ∘ C by a vapour transport method without catalysis and using a well selected value of the carrier gas flow. A transition state between grains and nanowires is reported being characterized by arrow-like structures which are constituted by a pyramidal head and a tail that is growing from the basal plane of the head. In order to understand the effect of growth conditions on the morphology of micro and nanostructures, an analysis of temperature and species concentration conditions has been carried out. In addition two different kinds of substrates have been u…
Structural defects in Hg1−xCdxI2 layers grown on CdTe substrates by vapor phase epitaxy
1997
Hg1−xCdxI2 20–25-μm-thick layers with a uniform composition in the range of x = 0.1–0.2 were grown on CdTe substrates by vapor phase epitaxy (VPE). The growth was carried out using an α-HgI2 polycrystalline source at 200 °C and in the time range of 30–100 h. The layers were studied by scanning electron microscopy (SEM) and high resolution synchrotron x-ray topography (SXRT). The SEM and SXRT images of Hg1−xCdxI2 VPE layers allow one to identify the defects affecting the layer structure. The two main types of structural defects in the layers are subgrain boundaries and densely spaced striations similar to those referred generally to as vapor grown HgI2 bulk crystals. The effect of the growth…
Nanodiamond‐Palladium Core–Shell Organohybrid Synthesis: A Mild Vapor‐Phase Procedure Enabling Nanolayering Metal onto Functionalized sp 3 ‐Carbon
2018
Physico-Chemical Interactions in the Flavor-Release Process
2017
The perception of flavor is induced by the release of aroma compounds in the vapor phase. The olfactory perception is not only related to the nature of aroma compounds initially present in the food, but also to their distribution between the different phases. After a description of the interactions established between the aroma compounds and different constituents of food, this chapter looks at physico-chemical characteristics of aroma compounds and at the composition and properties of food matrices. Then, in order to understand the behavior of aroma compounds in the matrices, study methods of interactions are described. The assessment of the release is done by determining the partition coe…
Calculation of the wetting parameter from a cluster model in the framework of nanothermodynamics
2003
The critical wetting parameter ${\ensuremath{\omega}}_{c}$ determines the strength of interfacial fluctuations in critical wetting transitions. In this Brief Report, we calculate ${\ensuremath{\omega}}_{c}$ from considerations on critical liquid clusters inside a vapor phase. The starting point is a cluster model developed by Hill and Chamberlin in the framework of nanothermodynamics [Proc. Natl. Acad. Sci. USA 95, 12779 (1998)]. Our calculations yield results for ${\ensuremath{\omega}}_{c}$ between 0.52 and 1.00, depending on the degrees of freedom considered. The findings are in agreement with previous experimental results and give an idea of the universal dynamical behavior of the cluste…