نتایج جستجو برای: noble gasses
تعداد نتایج: 10362 فیلتر نتایج به سال:
Here we present a new method for the sampling and quantitative extraction of dissolved He, Ne, Ar, Kr, and Xe from lake sediment samples leading to determinations of porewater noble gas concentration profiles and the isotopic ratios 3He/4He, 20Ne/22Ne, and 40Ar/36Ar. Bulk sediment is transferred from a sediment core into standard Cu sample tubes without exposure to the atmosphere or other gas r...
Mechanical and electromagnetic relations involved in the Trouton–Noble paradox are analysed on the basis of special relativity theory as well as on the basis of Maxwellian electrodynamics. It is shown that the paradox only arises when not all dynamical effects associated with the moving capacitor used by Trouton and Noble are considered. Crucial for the resolution of the paradox is the fact tha...
To manipulate the size of noble metal particles on a nanometer scale are priority subjects in the field of nanotechnology. So far various approaches have been developed to synthesize noble metal nanoparticles in controlled sizes and dimensions. Among them the colloidal systems become broadly used. These systems can be made up of several very different reactants and solvents: a continuous medium...
An efficient and convenient protocol for the synthesis of 2H-chromenones has been developed. In the presence of tBuOK in DMF, good to excellent yields of various chromenones were obtained from the corresponding salicylaldehydes and arylacetonitriles. No protection of inert gas atmosphere is required here.
Recently, it was shown that genuine Ng-Ng chemical bonds are present in the endohedral fullerenes Ng(2)@C(60) in the case of Ng=Xe, while it is more debatable whether a chemical bond exist for Ng=Ar and Kr. The lighter homologues with helium and neon are weakly bonded van der Waals complexes. The presence of a noble gas dimer inside the cage is expected to modify the exohedral reactivity of the...
The reaction of [LWCl] (3) [L = N(CH2CH2NiPr)3] with LiE(SiMe3)2 (E = P, As, Sb) yields the novel, neutral pnictido-bridged complexes [LW = E = WL] (5-7). By following the reaction, which starts from the LiP-(SiMe3)2 derivative, by 31P NMR spectroscopy, the formation of an intermediate with a terminal pnictido ligand can be ruled out. The paramagnetic complexes 5-7 are comprehensively spectrosc...
Rydberg spectral lines of an atom are sometimes superimposed on the continuous spectrum of a different configuration. Effects of interaction among different configurations in one of these cases are theoretically investigated, and a formula is obtained that describes the behavior of absorption spectrum intensity. This offers qualitative justification of some experimental results obtained by BEUT...
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