Search results for "fragmentation"
showing 10 items of 798 documents
A study on the fragmentation of sulfuric acid and dimethylamine clusters inside an Atmospheric Pressure interface Time Of Flight Mass Spectrometer
2021
Abstract. Sulfuric acid and dimethylamine vapours in the atmosphere can form molecular clusters, which participate in new particle formation events. In this work, we have produced, measured and identified clusters of sulfuric acid and dimethylamine using an electrospray ionizer coupled with a planar differential mobility analyser, connected to an atmospheric pressure interface time-of-flight mass spectrometer (ESI–DMA–APi-TOF MS). This set-up is suitable for evaluating the extent of fragmentation of the charged clusters inside the instrument. We evaluated the fragmentation of 11 negatively charged clusters both experimentally and using a statistical model based on quantum chemical data. The…
Real-time observation of a correlation-driven sub 3 fs charge migration in ionised adenine
2021
Sudden ionisation of a relatively large molecule can initiate a correlation-driven process dubbed charge migration, where the electron density distribution is expected to rapidly move along the molecular backbone. Capturing this few-femtosecond or attosecond charge redistribution would represent the real-time observation of electron correlation in a molecule with the enticing prospect of following the energy flow from a single excited electron to the other coupled electrons in the system. Here, we report a time-resolved study of the correlation-driven charge migration process occurring in the nucleic-acid base adenine after ionisation with a 15–35 eV attosecond pulse. We find that the produ…
Estimation of interfacial fracture toughness based on progressive edge delamination of a thin transparent coating on a polymer substrate
2010
Evaluation of interfacial toughness of sub-micron-thickness layers deposited on a ductile substrate is a challenging task which has motivated different experimental approaches Fragmentation testing was used in the present study as a means of interface characterization of a silicon-nitride-coated polyimide substrate. During the test, after an initial rapid segmentation-cracking phase, the coating fragments developed edge delaminations which propagated in a stable manner with further increase in the applied strain The debonding process was modelled by the finite element method Incorporating a cohesive zone at the front of the interfacial crack The edge cracks were found to be dominated by mod…
The translating subject: another double of Alejandra Pizarnik’s lyrical I?
2011
This article is the English version of "Le sujet traduisant : un autre double du je lyrique d‘Alejandra Pizarnik?" by Madeleine Stratford. It was not published on the print version of MonTI for reasons of space. The online version of MonTI does not suffer from these limitations, and this is our way of promoting plurilingualism. Fragmentation of the subject is one of the distinctive features of the poetry of Argentine writer Alejandra Pizarnik (1936-1072). Indeed, her poems convey her perpetual dissatisfaction with language, which cannot express her lyrical self in all of its complexity or resuscitate her biographical self. Particularly in her fourth poetry book, Árbol de Diana (1962), the p…
Angular momentum population in fragmentation reactions
2009
Neutron-deficient nuclei with N = 126 have been populated following projectile fragmentation of a 238U beam with energy 1 GeV/A. The decay of several previously reported isomers has been measured. This will allow us to calculate high-spin isomeric ratios and compare them with model calculations to allow a better understanding of the reaction mechanism. Algora, Alejandro, Alejandro.Algora@ific.uv.es ; Molina Palacios, Francisco Manuel, Francisco.Molina@ific.uv.es ; Rubio Barroso, Berta, Berta.Rubio@ific.uv.es
A discrete-element model for viscoelastic deformation and fracture of glacial ice
2015
a b s t r a c t A discrete-element model was developed to study the behavior of viscoelastic materials that are allowed to fracture. Applicable to many materials, the main objective of this analysis was to develop a model specifically for ice dynamics. A realistic model of glacial ice must include elasticity, brittle fracture and slow viscous deformations. Here the model is described in detail and tested with several benchmark simulations. The model was used to simulate various ice-specific applications with resulting flow rates that were compatible with Glen's law, and produced under fragmentation fragment-size distributions that agreed with the known analytical and experimental results.
Spatial fragmentation of, and US support for, the main multilateral institutions of the western order
2017
The growth of China-led minilateral initiatives mostly of a regional character has challenged the main multilateral institutions of the Western order and, ultimately, US authority. Faced with a progressive delegitimation of the institutional architecture that it promoted after World War II, the US, under the Obama administration, has acted to defend the existing main multilateral institutions of the order (UN, IMF, WB and WTO), attributing them with a strategic role. More than being radical, though, the reforms enacted have been incremental and pragmatic, but always imperfect. More importantly, they have not altered US influence, which is exercised mostly through informal means. This, howev…
Mass spectrometric study of oligourea macrocycles and their anion binding behavior
2009
Two series, one of tris-urea macrocycles and another of hexakis-urea macrocycles, are examined by (tandem) Fourier-transform ion cyclotron resonance (FTICR) mass spectrometry with respect to their fragmentation patterns and anion binding properties. All macrocycles are based on two different building blocks, one of which is a very rigid xanthene unit and the other one is a more flexible diphenyl ether. The composition and the sequence of these units thus determine their flexibility. During the fragmentation of deprotonated oligourea macrocycles in the gas phase, one urea N-CO bond is cleaved followed by a scrambling reaction within the macrocycle structure. Consequently, fragments are obser…
Towards a Novel Approach to Multimedia Data Mixed Fragmentation
2009
International audience; Distributed multimedia applications have emerged at an increasing rate during the last decade in several domains (video conferencing, e-health, virtual meeting rooms, etc). This has created several new challenging problems related to the data integration and fragmentation, user-oriented and adaptive interfaces, real time and network performances, etc. In this paper, we focus on the problem of data(base) fragmentation in a multimedia context. We recall in this respect that data fragmentation consists of reducing irrelevant data accesses by grouping data frequently accessed together in dedicated segments. We mainly address the issue of query and predicate implication r…
Les Carnets de Louis Calaferte : portrait de l’auteur en anarchiste chrétien
2014
National audience