نتایج جستجو برای: ambient atmosphere
تعداد نتایج: 103116 فیلتر نتایج به سال:
Methyl ethyl ketone (MEK) enters the atmosphere following direct emission from vegetation and anthropogenic activities, as well as being produced by the gas-phase oxidation of volatile organic compounds (VOCs) such as nbutane. This study presents the first overview of ambient MEK measurements at six different locations, characteristic of forested, urban and marine environments. In order to unde...
Flava Flavanone: Asymmetric conjugate additions to chromones and 4-quinolones are reported utilizing a single catalyst system formed in situ from Pd(OCOCF(3))(2) and (S)-tBuPyOX. Notably, these reactions are performed in wet solvent under ambient atmosphere, and employ readily available arylboronic acids as the nucleophile, thus providing ready access to these asymmetric heterocycles (see scheme).
We have modified and stabilized the ruthenium surface by depositing a self-assembled monolayer (SAM) of 1-hexadecanethiol on a polycrystalline ruthenium thin film. The growth mechanism, dynamics, and stability of these monolayers were studied. SAMs, deposited under ambient conditions, on piranha-cleaned and piranha + H2SO4 cleaned substrates were compared to monolayers formed on H-radical-clean...
We demonstrate measurement and control of nanoscale single-asperity friction by using cantilever probes featuring an in situ solid-state heater in contact with silicon oxide substrates. The heater temperature was varied between 25 and 790 °C. By using a low thermal conductivity sample, silicon oxide, we are able to vary tip temperatures over a broad range from 25 ± 2 to 255 ± 25 °C. In ambient ...
An organic FET employing a single crystal of a donor-acceptor system based on coronene tetracarboxylate and a methyl viologen derivative exhibited an impressive mobility of 0.53 cm(2) V(-1) s(-1), operating under 2 V in the ambient atmosphere. Quantum mechanical calculations have provided an insight into the hole-dominant transport in the crystal.
Abstract. The article describes results of experimental study of a plasma jet with the use of electric probes. The volt-ampere probe characteristics were determined from measurements with slowly varying biasing potential in the probe circuit. Plasma floating potential and plasma resistance in different positions in the vicinity of plasma jet were determined for various pressures of ambient atmo...
The deficiency of robust and practical methods for 18F-radiofluorination is a bottleneck for positron emission tomography (PET) tracer development. Here, we report the first transition-metal-assisted 18F-deoxyfluorination of phenols. The transformation benefits from readily available phenols as starting materials, tolerance of moisture and ambient atmosphere, large substrate scope, and translat...
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