نتایج جستجو برای: alkali metal
تعداد نتایج: 210259 فیلتر نتایج به سال:
A new application area using a very simple alkali metal chalcogenide, disodium diselenide (Na2Se2), has been developed. The prepared alkali metal chalcogenide (disodium diselenide, Na2Se2) acts as an anionic exchange precursor (PbS to PbS-PbSe), a Se precursor for metal selenide nanoparticles (Ag to Ag2Se), and a MCC (FeO-MCC) depending on the type of colloidal nanoparticles.
The gas-phase structures of alkali metal cation-cytosine complexes generated by electrospray ionization are probed via infrared multiple photon dissociation (IRMPD) action spectroscopy and theoretical calculations. IRMPD action spectra of five alkali metal cation-cytosine complexes exhibit both similar and distinctive spectral features over the range of ~1000-1900 cm(-1). The IRMPD spectra of t...
The effects of excess electronic charges transferred from alkali metals to Se atoms on the chain structure in liquid RbxSe1−x for x 0.5 are investigated by means of ab initio molecular-dynamics simulations. It is found that the interaction between Se chains is enhanced by the transferred electrons, and that the average length of Se chains becomes shorter with increasing alkali-metal concentrati...
Diazacrown ethers having two carbodithioate groups were synthesized, and their spectrophotometric properties were studied. Diammonium 1,4,10,13-tetraoxa-7,16-diazacycrooctadecane-N,N'-bis(carbodithioate) (DA18CC) and ammonium 1,4,10-trioxa-7,13-diazacycropentadecane-N,N'-bis(carbodithioate) (DA15CC) reacted with most heavy-metal ions through their two carbodithioate groups, and also reacted wit...
Investigating the release characteristics of alkali and alkaline earth metallic species (AAEMs) is of potential interest because of AAEM's possible useful service as catalysts in biomass thermal conversion. In this study, three kinds of typical Chinese biomass were selected to pyrolyse and their chars were subsequently steam gasified in a designed quartz fixed-bed reactor to investigate the rel...
We have observed depolarization effects when high intensity cold neutron beams are incident on alkali-metal spin-exchange-polarized 3He cells used as neutron spin filters. This was first observed as a reduction of the maximum attainable 3He polarization and was attributed to a decrease of alkali-metal polarization, which led us to directly measure alkali-metal polarization and spin relaxation o...
calixarenes are a readily available and important class of macrocycles in supramolecularchemistry. calixarenes have generated considerable interest due to their basket shaped structureand as useful building blocks to synthesize selective receptors for the guest species, notably alkali,alkaline earth, lanthanide and transition metal cations. in this work studied on the complexingproperties of a ...
Collective surface excitations in alkali-metal overlayers are observed using photoyield spectroscopy. Spectra for Na and K on Al~111! reveal a multipole surface plasmon and bulklike overlayer plasmon. In contrast, Li on Al exhibits only the multipole mode. In the submonolayer regime, all three alkali metals provide evidence for the threshold excitation. Time-dependent density-functional calcula...
We report the first direct solution NMR detection of the alkali metal cations (23Na+, 39K+, and 87Rb+) residing inside G-quadruplex channel structures formed by guanosine 5'-monophosphate and a DNA oligomer, d(TG4T). In solution, these channel alkali metal cations are tightly bound to the G-quadruplex structure and have been considered to be "invisible" to NMR spectroscopy for many years. Our f...
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