SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "WFRF:(A. Johnsson) srt2:(2020)"

Sökning: WFRF:(A. Johnsson) > (2020)

  • Resultat 1-10 av 14
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  • Manschwetus, B., et al. (författare)
  • Ultrafast ionization and fragmentation dynamics of polycyclic atomatic hydro-carbons by XUV radiation
  • 2020
  • Ingår i: Free Electron Laser. - : IOP Publishing. - 1742-6588. ; 1412
  • Konferensbidrag (refereegranskat)abstract
    • In the interstellar medium polycyclic aromatic hydrocarbon molecules (PAH) are exposed to strong ionizing radation leading to complex organic photochemistry. We investigated these ultrafast fragmentation reac-tions after ionization of the PAHs phenanthrene, fluorene and pyrene at a wavelength of 30.3 nm using pump probe spectroscopy at a free electron laser. We observe double ionization and afterwards hydrogen abstraction and acetylene loss with characteristic time scales for the reaction processes below one hundred femtoseconds.
  •  
2.
  • Ilchen, M., et al. (författare)
  • X-ray spectroscopy on ultrafast-decaying core-excited atomic ions
  • 2020
  • Ingår i: Charge-exchange. - : IOP Publishing. - 1742-6588. ; 1412
  • Konferensbidrag (refereegranskat)abstract
    • Results from the first soft X-ray user experiment at the European XFEL on nonlinear photon-matter interaction will be presented. Angle-resolved electron time-of-flight spectroscopy employed at the AQS (Atomic- like Quantum Systems) endstation of the SQS (Small Quantum Systems) instrument reveals insight into the character of resonances in highly transient, core ionized neon ions, i.e. Ne:+ 1s12s22p6 → Ne+&∗ 1s02s22p6np, together with their respective relaxation dynamics. Enabled by the unique properties of the European XFEL, novel perspectives on efficient nonlinear spectroscopy will be discussed.
  •  
3.
  • Makos, I, et al. (författare)
  • Α 10-gigawatt attosecond source for non-linear XUV optics and XUV-pump-XUV-probe studies
  • 2020
  • Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 10:1
  • Tidskriftsartikel (refereegranskat)abstract
    • The quantum mechanical motion of electrons and nuclei in systems spatially confined to the molecular dimensions occurs on the sub-femtosecond to the femtosecond timescales respectively. Consequently, the study of ultrafast electronic and, in specific cases, nuclear dynamics requires the availability of light pulses with attosecond (asec) duration and of sufficient intensity to induce two-photon processes, essential for probing the intrinsic system dynamics. The majority of atoms, molecules and solids absorb in the extreme-ultraviolet (XUV) spectral region, in which the synthesis of the required attosecond pulses is feasible. Therefore, the XUV spectral region optimally serves the study of such ultrafast phenomena. Here, we present a detailed review of the first 10-GW class XUV attosecond source based on laser driven high harmonic generation in rare gases. The pulse energy of this source largely exceeds other laser driven attosecond sources and is comparable to the pulse energy of femtosecond Free-Electron-Laser (FEL) XUV sources. The measured pulse duration in the attosecond pulse train is 650 ± 80 asec. The uniqueness of the combined high intensity and short pulse duration of the source is evidenced in non-linear XUV-optics experiments. It further advances the implementation of XUV-pump-XUV-probe experiments and enables the investigation of strong field effects in the XUV spectral region.
  •  
4.
  • Mazza, T., et al. (författare)
  • Mapping Resonance Structures in Transient Core-Ionized Atoms
  • 2020
  • Ingår i: Physical Review X. - 2160-3308. ; 10:4
  • Tidskriftsartikel (refereegranskat)abstract
    • The nature of transient electronic states created by photoabsorption critically determines the dynamics of the subsequently evolving system. Here, we investigate K-shell photoionized atomic neon by absorbing a second photon within the Auger-decay lifetime of 2.4 fs using the European XFEL, a unique high-repetition-rate, wavelength-tunable x-ray free-electron laser. By high-resolution electron spectroscopy, we map out the transient Rydberg resonances unraveling the details of the subsequent decay of the hollow atom. So far, ultra-short-lived electronic transients, which are often inaccessible by experiments, were mainly inferred from theory but are now addressed by nonlinear x-ray absorption. The successful characterization of these resonances with femtosecond lifetimes provides the basis for a novel class of site-specific, nonlinear, and time-resolved studies with strong impact for a wide range of topics in physics and chemistry.
  •  
5.
  •  
6.
  •  
7.
  • Johnsson, Björn A., et al. (författare)
  • Towards end-user development of graphical user interfaces for internet of things
  • 2020
  • Ingår i: Future Generation Computer Systems. - : Elsevier BV. - 0167-739X. ; 107, s. 670-680
  • Tidskriftsartikel (refereegranskat)abstract
    • Graphical user interface (GUI) development is generally complicated, time-consuming, and requires programming knowledge. In the context of the internet of things, this work focuses on producing an efficient development approach that also supports non-experts. We introduce a novel "inverted" development approach that does not require program code to be written - a step towards supporting end-user development in the given context. The approach is realized as a language for describing GUIs, interpreters for rendering GUIs, and a graphical tool for creating and editing GUIs. The work is evaluated in a number of research projects in the domain of e-health; we conclude that the GUI language is practically viable for building professional-grade GUIs. Furthermore, the presented editor is compared directly to a market leading product in a controlled experiment. From this, we conclude that the editor is accessible to new users, and that it can be more efficient to use than the commercial alternative.
  •  
8.
  • Johnsson, Jesper, et al. (författare)
  • Functional outcomes associated with varying levels of targeted temperature management after out-of-hospital cardiac arrest — An INTCAR2 registry analysis
  • 2020
  • Ingår i: Resuscitation. - : Elsevier BV. - 0300-9572 .- 1873-1570. ; 146, s. 229-236
  • Tidskriftsartikel (refereegranskat)abstract
    • Introduction: Targeted temperature management (TTM) after out-of-hospital cardiac arrest (OHCA) has been recommended in international guidelines since 2005. The TTM-trial published in 2013 showed no difference in survival or neurological outcome for patients randomised to 33 °C or 36 °C, and many hospitals have changed practice. The optimal utilization of TTM is still debated. This study aimed to analyse if a difference in temperature goal was associated with outcome in an unselected international registry population. Methods: This is a retrospective observational study based on a prospective registry — the International Cardiac Arrest Registry 2. Patients were categorized as receiving TTM in the lower range at 32–34 °C (TTM-low) or at 35–37 °C (TTM-high). Primary outcome was good functional status defined as cerebral performance category (CPC) of 1–2 at hospital discharge and secondary outcome was adverse events related to TTM. A logistic regression model was created to evaluate the independent effect of temperature by correcting for clinical and demographic factors associated with outcome. Results: Of 1710 patients included, 1242 (72,6%) received TTM-low and 468 (27,4%) TTM-high. In patients receiving TTM-low, 31.3% survived with good outcome compared to 28.8% in the TTM-high group. There was no significant association between temperature and outcome (p = 0.352). In analyses adjusted for baseline differences the OR for a good outcome with TTM-low was 1.27, 95% CI (0.94–1.73). Haemodynamic instability leading to discontinuation of TTM was more common in TTM-low. Conclusions: No significant difference in functional outcome at hospital discharge was found in patients receiving lower- versus higher targeted temperature management.
  •  
9.
  • Maclot, Sylvain, et al. (författare)
  • Dissociation dynamics of the diamondoid adamantane upon photoionization by XUV femtosecond pulses
  • 2020
  • Ingår i: Scientific Reports. - : Nature Research. - 2045-2322. ; 10:1
  • Tidskriftsartikel (refereegranskat)abstract
    • This work presents a photodissociation study of the diamondoid adamantane using extreme ultraviolet femtosecond pulses. The fragmentation dynamics of the dication is unraveled by the use of advanced ion and electron spectroscopy giving access to the dissociation channels as well as their energetics. To get insight into the fragmentation dynamics, we use a theoretical approach combining potential energy surface determination, statistical fragmentation methods and molecular dynamics simulations. We demonstrate that the dissociation dynamics of adamantane dications takes place in a two-step process: barrierless cage opening followed by Coulomb repulsion-driven fragmentation.
  •  
10.
  • Maclot, Sylvain, et al. (författare)
  • Photodissociation dynamics of the diamondoid adamantane induced by attosecond XUV pulses
  • 2020
  • Ingår i: 31st international conference on photonic, electronic and atomic collisions (icpeac xxxi). - : IOP Publishing. ; 1412
  • Konferensbidrag (refereegranskat)abstract
    • Adamantane is the simplest of the diamondoid molecules, which due to their high stability are of high interest both in astrophysics and nanotechnology. This work investigates the molecular photodissociation after ionization by attosecond XUV pulses. The fragmentation dynamics is inferred by means of velocity map imaging spectrometry, covariance analysis techniques and quantum chemistry calculations.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-10 av 14

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy