نتایج جستجو برای: liquid fluorine
تعداد نتایج: 224702 فیلتر نتایج به سال:
Time-resolved infra-red (IR) absorption spectroscopy is used to follow the production of HF from the reaction of fluorine atoms in liquid acetonitrile (CH3CN). Photolysis of dissolved XeF2 using ∼50 fs duration, 267 nm laser pulses generates F atoms and XeF on prompt (sub-ps) timescales, as verified by broadband transient electronic absorption spectroscopy. The fundamental vibrational band of H...
We report construction of a portable nuclear magnetic resonance sensor with a single-sided open probe design. The resulting magnetic field inhomogeneity is compensated by a pulse sequence that takes advantage of parallel inhomogeneity in the applied radio frequency field. We can thereby acquire fluorine-19 spectra of liquid fluorocarbons with 8 parts per million resolution, surmounting the long...
Phase transitions (liquid-solid, solid-solid) triggered by temperature changes are studied in free nanosized clusters of TeF6 (SF6) with different negative charges assigned to the fluorine atoms. Molecular dynamics simulations at constant energy show that the charge increase from qF =0.1e to qF =0.25e shifts the melting temperature towards higher values and some of the metastable solid states d...
ZSM-5 zeolites were prepared at neutral pH by fluoride-mediated synthesis. The degree of crystallinity, the specific surface area and the crystal size are higher than those of the zeolites prepared under alkaline conditions. Moreover, by varying the F/Si ratio from 0.3 to 1.6, the H–[F]–ZSM-5 zeolites with crystal size ranging from 10 to 75 lm and the specific surface areas from 60 up to 350 m/...
Spin-lattice relaxation rates (R(1H) and R(1F)) of two nuclear species ((1)H and (19)F) are measured at different temperatures in the isotropic phase of a liquid crystal (4(')-butoxy-3(')-fluoro-4-isothiocyanatotolane-4OFTOL), over a wide range of Larmor frequency (10 kHz-50 MHz). Their dispersion profiles are found to be qualitatively very different, and the R(1F) in particular shows significa...
ZnO nanoneedle arrays were grown vertically on a fluorine-doped tin oxide-coated glass by hydrothermal method at a relatively low temperature. A self-powered photoelectrochemical cell-type UV detector was fabricated using the ZnO nanoneedles as the active photoanode and H2O as the electrolyte. This solid-liquid heterojunction offers an enlarged ZnO/water contact area and a direct pathway for el...
ABSTRACT Liquid-repellent surfaces based on slippery liquid-infused porous substrates (SLIPS) were prepared from porous, nanostructured silicon surfaces with different surface functionalization, infused with the polar ionic liquid 1-ethyl-3-methylimidazolium methylsulfate ([C2mim]MeSO4). Contrary to nonpolar SLIPS based on perfluorinated substrates and infusion liquids, [C2mim]MeSO4 forms stabl...
We present experimental results on the bulk flexoelectric coefficients e and effective elastic coefficients K of non-symmetric bimesogenic liquid crystals when the number of terminal and lateral fluoro substituents is increased. These coefficients are of importance because the flexoelastic ratio e/K governs the magnitude of flexoelectro-optic switching in chiral nematic liquid crystals. The stu...
The fluorous biphase system has been applied successfully to a wide range of homogeneous catalyses with excellent catalyst recovery and reuse being reported. However, it is unlikely to be exploited commercially because of intersolvent leaching problems, the prohibitive expense of the perfluorocarbon solvents and concerns about their environmental persistence. An alternative approach, designed b...
Implanted fluorine is observed to behave unusually in silicon, manifesting apparent uphill diffusion and reducing diffusion and enhancing activation of boron. In order to investigate fluorine behavior, we calculate the energy of fluorine defect structures in the framework of density functional theory. In addition to identifying the ground-state configuration and diffusion migration barrier of a...
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