Search results for "Solid"
showing 10 items of 3575 documents
1-METHYLCYCLOPROPENE DELAYS RIPENING AND IMPROVES POSTHARVEST QUALITY OF WHITE FLESH LOQUAT
2015
The ethylene inhibitor 1-methylcyclopropene (1-MCP) delayed ripening and improved postharvest fruit quality of loquat (Eriobotrya japonica Lindl.). 1-MCP was used on the white flesh sub-acid loquat cultivars ‘Claudia’ and ‘BRT20’ to evaluate the possible effect on fruit ripening and to prevent negative effects of cold storage, like internal browning and flesh leatheriness. 1-MCP was applied at 2°C for 20 h and concentrations of 1 and 5 μl L-1. After 1-MCP treatment fruit were held at 2°C for 7, 14, and 21 days and then moved to 18°C for 5 days. Fruit flesh firmness, titratable acidity (TA), total soluble content (TSS), weight loss, internal browning and flesh leatheriness were evaluated at …
Folding and dimerization of resorcarene tetrasulfonates
2001
In the solid state and in CDCl3 resorcarene tetramesitylsulfonates fold by intramolecular SO⋯H–O hydrogen bonds and dimerise via intermolecular O–H⋯OH hydrogen bonding.
Intense laser effects on donor impurity in a cylindrical single and vertically coupled quantum dots under combined effects of hydrostatic pressure an…
2010
WOS: 000280235800010
Ionic conductivity in monophasic Ag2xNa2(1 − x)ZnSiO4 materials with 0 ≤ x ≤ 1
1996
Abstract Solid solution samples Ag 2 x Na 2(1 − x ) ZnSiO 4 with 0 ≤ x ≤ 1 have been prepared by heat treating powder mixtures of Na 2 ZnSiO 4 and Ag 2 ZnSiO 4 at 300 °C and characterised by X-ray powder diffraction. The ionic conductivity of the solid solution has been determined as a function of composition and temperature by means of impedance measurements. The ionic conductivity of the mixed-mobile ion compositions (0 ≤ x ≤ 1) shows no substantial deviation from the mutually similar conductivities of the end compositions Na 2 ZnSiO 4 and Ag 2 ZnSiO 4 , and neither activation energy nor conductivity pre-factor varies significantly with composition. The results indicate that the mixed-alk…
Selective oxidation of ethane: Developing an orthorhombic phase in Mo–V–X (X=Nb, Sb, Te) mixed oxides
2009
Abstract Mo–V–X (X = Nb, Sb and/or Te) mixed oxides have been prepared by hydrothermal synthesis and heat-treated in N2 at 450 °C or 600 °C for 2 h. The calcination temperature and the presence or absence of Nb determines the nature of crystalline phases in the catalyst. Nb-containing catalysts heat-treated at 450 °C are mostly amorphous solids, while Nb-free catalysts heat-treated at 450 °C and samples treated at 600 °C clearly contain crystalline phases. TPR-H2 experiments show higher H2-consumption on catalysts with amorphous phases. Catalytic results in the oxidative dehydrogenation of ethane indicate that the selective production of the olefin is strongly related to the development of …
Preparation of multi-nanocrystalline transition metal oxide (TiO2–NiTiO3) mesoporous thin films
2005
Ordered mesoporous TiO2–NiTiO3 thin films, with nickel content x < 0.5, were prepared by dip-coating an acidic solution of hydrolysed transition metal chlorides in controlled humidity, followed by a very careful annealing treatment. These latter treatments were studied by in situ SAXS-WAXS experiments involving synchrotron radiation and TEM analysis. They revealed that the walls can be composed of amorphous, single crystalline or multi crystalline nanoparticles depending on x and the conditions applied during the thermal treatment.
Structural Evolution and Vanadium Distribution in the Preparation of V4+-ZrSiO4 Solid Solutions from Gels
2004
Vanadium-containing ZrSiO4-gel precursors with nominal compositions Vx-ZrSiO4 with x= 0.0, 0.002, 0.004, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.1, and 0.2 were prepared using a previously reported procedure and thermally treated over a range of temperature up to the formation of the V4+-ZrSiO4 solid solution. The structural evolution and the V4+ location and its homogenous distribution were followed using powder X-ray diffractometry and electron spin resonance spectroscopy (ESR). Our experiments showed that a tetragonal form of V4+-ZrO2 was the first crystalline phase obtained on heating the gels. On further heating, a phase transformation to the monoclinic form of V4+-ZrO2 took place. Final…
Low-temperature methyl group dynamics of hexamethylbenzene in crystalline and glassy matrices as studied by 2H NMR
1991
Abstract 2 H NMR spectra of hexamethylbenzene (HMB) in protonated crystalline and amorphous matrices at low temperatures are presented. All spectra reveal lineshape changes which can be attributed to methyl group tunnelling. Compared to neat HMB, a drastic increase of the tunnelling frequency is found for all systems. This indicates that the hindering potential originates predominantly from intermolecular forces. We studied the temperature dependence of these spectra and the spin-lattice relaxation in order to exclude a distribution of motional correlation times describing a thermally activated process. In addition, we find a distortion of the methyl tetrahedron.
Designing Solid Solutions of Enantiomers: Lack of Enantioselectivity of Chiral Naphthalimide Derivatives in the Solid State
2017
The enantiomers of a previously reported naphthalimide derivative are shown in this study to form a solid solution; furthermore, on the basis of the knowledge of solid solution structural aspects other naphthalimide derivatives have been synthesized and shown to lack the enantioselectivity in the solid state. The structural origin of solid solution formation is the same as observed in most of the cases in the literaturequasi-centrosymmetric structures form at nonracemic compositions where the most abundant enantiomer adjusts its conformation to mimic the absent one. Such solid solutions belong to the type showing some enantioselectivity. An extended single crystal X-ray diffraction study o…
Sicilian bottled natural waters: Major and trace inorganic components
2013
Sixteen bottled waters of various Sicilian brands, 11 natural mineral waters and five normal drinking waters, were analyzed for major and trace inorganic components by ion chromatography (IC) and inductively coupled plasma-mass spectrometry (ICP-MS), respectively. The bottled waters represent a variety of water types with significantly different compositions in terms of salinity, major components and trace elements. Chemically, they range from Ca–HCO3 and Ca–SO4 to Na–HCO3 types. Total dissolved solids ranges from 54 to 433 mg/L, total hardness from 25 to 238 mg/L CaCO3, and measured Na content from 5.7 to 57 mg/L. According to total dissolved ions, all the bottled waters were classified as…