Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 3 de 3
Filtrar
Mais filtros

Base de dados
Ano de publicação
Tipo de documento
País de afiliação
Intervalo de ano de publicação
1.
Chemistry ; 26(52): 12075-12080, 2020 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-32293757

RESUMO

Terrestrial volcanism has been one of the dominant geological forces shaping our planet since its earliest existence. Its associated phenomena, like atmospheric lightning and hydrothermal activity, provide a rich energy reservoir for chemical syntheses. Based on our laboratory simulations, we propose that on the early Earth volcanic activity inevitably led to a remarkable production of formic acid through various independent reaction channels. Large-scale availability of atmospheric formic acid supports the idea of the high-temperature accumulation of formamide in this primordial environment.

2.
Astrobiology ; 20(12): 1476-1488, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32955922

RESUMO

Chemical environments of young planets are assumed to be significantly influenced by impacts of bodies lingering after the dissolution of the protoplanetary disk. We explore the chemical consequences of impacts of these bodies under reducing planetary atmospheres dominated by carbon monoxide, methane, and molecular nitrogen. Impacts were simulated by using a terawatt high-power laser system. Our experimental results show that one-pot impact-plasma-initiated synthesis of all the RNA canonical nucleobases and the simplest amino acid glycine is possible in this type of atmosphere in the presence of montmorillonite. This one-pot synthesis begins with de novo formation of hydrogen cyanide (HCN) and proceeds through intermediates such as cyanoacetylene and urea.


Assuntos
Glicina , Cianeto de Hidrogênio , Nucleotídeos , Atmosfera , Meio Ambiente Extraterreno
3.
Phys Rev E ; 101(1-1): 013204, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32069635

RESUMO

The nuclear reaction known as proton-boron fusion has been triggered by a subnanosecond laser system focused onto a thick boron nitride target at modest laser intensity (∼10^{16}W/cm^{2}), resulting in a record yield of generated α particles. The estimated value of α particles emitted per laser pulse is around 10^{11}, thus orders of magnitude higher than any other experimental result previously reported. The accelerated α-particle stream shows unique features in terms of kinetic energy (up to 10 MeV), pulse duration (∼10 ns), and peak current (∼2 A) at 1 m from the source, promising potential applications of such neutronless nuclear fusion reactions. We have used a beam-driven fusion scheme to explain the total number of α particles generated in the nuclear reaction. In this model, protons accelerated inside the plasma, moving forward into the bulk of the target, can interact with ^{11}B atoms, thus efficiently triggering fusion reactions. An overview of literature results obtained with different laser parameters, experimental setups, and target compositions is reported and discussed.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA