Search results for "PLASMA"
showing 10 items of 4043 documents
High precision numerical approach for Davey–Stewartson II type equations for Schwartz class initial data
2020
We present an efficient high-precision numerical approach for Davey–Stewartson (DS) II type equa- tions, treating initial data from the Schwartz class of smooth, rapidly decreasing functions. As with previous approaches, the presented code uses discrete Fourier transforms for the spatial dependence and Driscoll’s composite Runge–Kutta method for the time dependence. Since DS equations are non-local, nonlinear Schrödinger equations with a singular symbol for the non-locality, standard Fourier methods in practice only reach accuracy of the order of 10−6or less for typical examples. This was previously demonstrated for the defocusing integrable case by comparison with a numerical approach for …
Low-temperature thermal and plasma-enhanced atomic layer deposition of metal oxide thin films
2017
Atomic layer deposition (ALD) is a method for thin film fabrication with atomic level precision. This thesis focuses on low-temperature thermal and plasma- enhanced ALD and presents results on thin film growth by these techniques with examples of common ALD materials: Al2O3, ZnO and TiO2. As an example of limitations of the thermal ALD the nucleation and growth of Al2O3 and ZnO films on different grades of poly(methyl methacrylate) (PMMA) are presented, showing that the initiation of the growth is strongly dependent on both the deposited material and the substrate. A potential application of the ALD ZnO films in polymer surface functionalization is demonstrated by changing in the surface wettab…
Network-based indices of individual and collective advising impacts in mathematics
2020
AbstractAdvising and mentoring Ph.D. students is an increasingly important aspect of the academic profession. We define and interpret a family of metrics (collectively referred to as “a-indices”) that can potentially be applied to “ranking academic advisors” using the academic genealogical records of scientists, with the emphasis on taking into account not only the number of students advised by an individual, but also subsequent academic advising records of those students. We also define and calculate the extensions of the proposed indices that account for student co-advising (referred to as “adjusted a-indices”). In addition, we extend some of the proposed metrics to ranking universities a…
Mandibular involvement of solitary plasmocytoma : a case report
2007
Plasma cell neoplasms (multiple myeloma, solitary plasmocytoma of bone and extra medullar plasmocytoma) are characterized by a monoclonal neoplastic proliferation of plasma cells. Solitary plasmocytoma of bone (SPB) is a localized form of them. SPB is most frequently seen in vertebrae and secondarily in long bones. Its presence in jaws is extremely rare and when it is seen, angulus and ramus mandible are most common sites of occurrence. Prognosis of SPB is worse than extra medullar plasmacytoma (EMP) and approximately 50% of SPB will transform to multiple myelom. A 76- year old woman consulted to our clinic with a chief complaint of slowly developed swelling in her mandible. She had an oper…
LIISA-ionilähteen vetyplasman VUV-spektrin ja H ̄ -ionisuihkun intensiteetin korrelaatio
2016
Tässä työssä tutkitaan negatiivisen vetyionilähteen plasman tuottaman ultraviolettisäteilyn ja ionilähteen tuottaman negatiivisen vetyionisuihkun intensiteetin välistä korrelaatiota. Työssä löydettiin korrelaatio VUV-spektrin tiettyjen aallonpituusalueiden intensiteettien välisen suhteen ja Faraday-kupilla mitatun suihkuintensiteetin välillä. Korrelaatio ei kuitenkaan ole yksiselitteinen ja pätee ainoastaan rajoitetussa painealueessa. Vetyplasman molekylaarisen emission Lyman-vyön spektrin ja suihkun korrelaation tarkastelusta huomattiin, että elektronisen perustilan vibronisten viritystilojen 10 ja 11 tuoton suhde korkeampien viritystilojen tuottoon on olennainen negatiivisten vetyionien t…
Tin resonance-ionization schemes for atomic- And nuclear-structure studies
2020
This paper presents high-precision spectroscopic measurements of atomic tin using five different resonance-ionization schemes performed with the collinear resonance-ionization spectroscopy technique. Isotope shifts were measured for the stable tin isotopes from the $5{s}^{2}5{p}^{2}\phantom{\rule{0.28em}{0ex}}^{3}{P}_{0,1,2}$ and ${}^{1}{S}_{0}$ to the $5{s}^{2}5p6s\phantom{\rule{0.28em}{0ex}}^{1}{P}_{1},^{3}{P}_{1,2}$ and $5{s}^{2}5p7s{\phantom{\rule{0.28em}{0ex}}}^{1}{P}_{1}$ atomic levels. The magnetic dipole hyperfine constants ${A}_{\mathrm{hf}}$ have been extracted for six atomic levels with electron angular momentum $Jg0$ from the hyperfine structures of nuclear spin $I=1/2$ tin isot…
Spectroscopy of short-lived radioactive molecules
2020
Molecular spectroscopy offers opportunities for the exploration of the fundamental laws of nature and the search for new particle physics beyond the standard model1–4. Radioactive molecules—in which one or more of the atoms possesses a radioactive nucleus—can contain heavy and deformed nuclei, offering high sensitivity for investigating parity- and time-reversal-violation effects5,6. Radium monofluoride, RaF, is of particular interest because it is predicted to have an electronic structure appropriate for laser cooling6, thus paving the way for its use in high-precision spectroscopic studies. Furthermore, the effects of symmetry-violating nuclear moments are strongly enhanced5,7–9 in molecu…
Three-dimensional skyrmions in spin-2 Bose–Einstein condensates
2017
We introduce topologically stable three-dimensional skyrmions in the cyclic and biaxial nematic phases of a spin-2 Bose-Einstein condensate. These skyrmions exhibit exceptionally high mapping degrees resulting from the versatile symmetries of the corresponding order parameters. We show how these structures can be created in existing experimental setups and study their temporal evolution and lifetime by numerically solving the three-dimensional Gross-Pitaevskii equations for realistic parameter values. Although the biaxial nematic and cyclic phases are observed to be unstable against transition towards the ferromagnetic phase, their lifetimes are long enough for the skyrmions to be imprinted…
Spectral properties of X-ray bright variable sources in the Taurus Molecular Cloud
2006
We analyze 19 bright variable X-ray sources detected in the XMM-Newton Extended Survey of the Taurus Molecular Cloud (XEST), in order to characterize the variations with time of their coronal properties and to derive informations on the X-ray emitting structures. We performed time-resolved spectroscopy of the EPIC PN and MOS spectra of the XEST sources, using a model with one or two thermal components, and we used the time evolution of the temperatures and emission measures during the decay phase of flares to derive the size of the flaring loops. The light curves of the selected sources show different types of variability: flares, long-lasting decay or rise through the whole observation, sl…
High Energy Emission and its Variability in Young Stellar Objects
2019
Young stars show a variety of highly energetic phenomena, from accretion and outflow processes to hot coronal plasmas confined in their outer atmosphere, all regulated by the intense stellar magnetic fields. Many aspects on each of these phenomena are debated, but, most notably, their complex mutual interaction remains obscure. In this work I report how these phenomena are simultaneously responsible for the high-energy emission from young stars, with a special focus on the expected and observed variability in the X-ray band. Investigating variations in the X-ray emission from young stars allows us to pose constraints on flare and coronal plasma properties, coronal heating, accretion stream …