Papers by Eberhard R Hilf
Academic electronic theses and dissertations (ETDs) should be openly accessible to serve best the... more Academic electronic theses and dissertations (ETDs) should be openly accessible to serve best the scientific progress, and inform the scientific community as a whole on the results. This is technically supported at universities by their institutional repositories, by global open archives, and by some publishers. Over the years the percentage of ETDs which are open access (OA) is rising worldwide and in all scientific disciplines. Open, stated Peter Murray-Rust in his keynote at the ETD2014 conference at Leicester, UK, should be the default, not the exception. However, the reality is different. Even in institutional repositories (IRs) created to provide access to the scientific output of an academic institution and as a central sector of the so-called green road to open access, more or less important parts of the scientific production are missing. This is because of lack of awareness, embargo, deposit of metadata without full text, confidential content etc. ETDs, in particular, are d...
PDMS, the ’Plasma’ Desorption Mass Spectrometry, is a method to desorb even very large and fragil... more PDMS, the ’Plasma’ Desorption Mass Spectrometry, is a method to desorb even very large and fragile organic molecules up to some 10.000 a.m.u. by means of very fast, energetic (MeV/nucleon) heavy ions impinging a solid surface with sample molecules adsorbed on it. A brief sketch of the underlying physics of the process is given. Several programmes to analyze, calculate, and transfer PDMS spectra are described in detail.
Die Blue Ribbon Task Force (BRTF), eine anglo-amerikanische Expertengruppe, betrachtet die Langze... more Die Blue Ribbon Task Force (BRTF), eine anglo-amerikanische Expertengruppe, betrachtet die Langzeitarchivierung nicht als rein technisches, sondern in erster Linie als sozioökonomisches Problem. In ihrem im Februar 2010 erschienenen Abschlussreport 1 formuliert sie Empfehlungen, wie sich Ressourcen für die Langzeitarchivierung nachhaltig mobilisieren lassen können. Unter dem Dach des Kompetenznetzwerks zur digitalen Langzeitarchivierung in Deutschland, nestor, haben sich führende Experten 2 mit den BRTF-Empfehlungen auseinandergesetzt und ihre Übertragbarkeit auf Deutschland geprüft. Die Ergebnisse sowie eigene Empfehlungen zur Langzeitarchivierung sind in diesem Positionspapier niedergelegt und sollen Wege zur Umsetzung aufzeigen.
A specialized search engine for scientific documents has been adapted by us to look for eLearning... more A specialized search engine for scientific documents has been adapted by us to look for eLearning material available on the World Wide Web. Starting from known professional scientific institutions worldwide, listed in the PhysDep service, our system looks for probably relevant material. The method used for the search is explained and first results of the application on the domain of eLearning are shown.
ABSTRACT A synopis of the transmutations of matter in a supernova to the final stages of neutron-... more ABSTRACT A synopis of the transmutations of matter in a supernova to the final stages of neutron-star matter, r-nuclei, p-nuclei and cosmic rays if given. In particular discussed are (1) the freezing-out of nuclear reactions during cooling, (2) the consequences of an improved β-decay and β-delayed neutron emission systematics for the calculations of the r-process element abundances and of its application to the estimation of the nucleosynthesis-age of the galaxy, (3) the production mechanism of the high-energy light-element cosmic rays, which we propose to originate from the neutron star's surface.
Physik Journal
ABSTRACT Suchen, finden und erhalten von Informationen kann mehr Last als Lust sein. Sie suchen d... more ABSTRACT Suchen, finden und erhalten von Informationen kann mehr Last als Lust sein. Sie suchen die Promotionsordnungen aller deutschen Physik-Fachbereiche? Eintippen des Suchworts „Promotionsordnungen” in ein Suchfeld des neuen Internet-Dienstes PhysDep liefert Ihnen die Ordnungen von den acht Fachbereichen, die diese bereits in ihren heimischen Rechner eingegeben und über ihren lokal eingerichteten WWW-Server (Internet-Knotenpunkt) zugänglich gemacht haben. Aber suchten Sie nicht eigentlich nur nach einer speziellen Zweitgutachter-Regelung in den Promotionsordnungen anderer Fachbereiche? Oder als zweites Beispiel: Wo finde ich nur die Telefonnummer des Kollegen Y? Ist er nicht kürzlich an eine andere Hochschule gewechselt? Aber wohin? Eigentlich suche ich seine neueste Arbeit, deren Titel ich aber nicht erinnere, deswegen wollte ich ihn ja anrufen… Die Informationen, die wir benötigen, sind nicht immer die Dokumente, nach denen wir suchen. — Viele qualitativ verschiedene, manchmal verschlungene, oft nur intuitiv gewählte Wege führen zur gewünschten Antwort. Den Suchenden interessiert aber nur das Endergebnis, nicht der Weg der Suche, oder gar Ort, Art und Organisation der Quellen. Informationsmanagement als Dienstleistung in der Physik, so ist zu hoffen, sollte daher umfassend alle Informationstypen und Dokumentenarten, alle relevanten Orte und Anbieter umfassen. — Wie dies im Zeitalter der elektronischen Dienste einmal dauerhaft und zweckmäßig organisiert sein wird, mag noch nicht klar zu erkennen sein. Hier soll ein kurzer Einblick in einige aktuelle Aktivitäten und Pläne gegeben werden, in denen die DPG involviert ist [1].
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms
Experiments on photon production in solid films of organic molecules by the impact of Z52Cf-fissi... more Experiments on photon production in solid films of organic molecules by the impact of Z52Cf-fission fragments are presented. The samples were mainly prepared with Coronene or POPOP sprayed onto an aluminized polyester foil using the nebulizer spray technique. It is demonstrated by scanning electron micrographs that this technique is a suitable method to prepare homogeneous solid films of organic compounds by producing layers of microcrystals. Time profiles and photon spectra have been determined by bombarding these samples with *"Cf-fission fragments as well as, for comparison, by exciting with light. The results give evidence that the photons induced by fission fragment bombardment originate from molecular fluorescence in the solid sample. Approximately 500 photons per fission fragment have been produced within a 100 ns time window in about 2 pm thick POPOP samples. The photon yield has been observed to increase linearly with the thickness of the sample up to about 16 pm. Only very few photons per fission fragment has been obtained with Rhodamine 6G samples and the same low photon yield has been observed under the bombardment with 2 keV electrons. These results probably indicate that the excitation of molecular species by energetic S-electrons is the necessary step in the process of photon production by fast heavy ions. Photons which have been additionally produced when extracting positive ions come also from molecular fluorescence in the samples. But this fluorescence is excited by electrons which originate from impacts of fission fragments on components of the acceleration system and which are accelerated back to the sample.
Le Journal de Physique Colloques
RCsumC-Les processus d e desorption en HIID (Heavy Ion Induced Desorption) sont simules 3 l ' a i... more RCsumC-Les processus d e desorption en HIID (Heavy Ion Induced Desorption) sont simules 3 l ' a i d e d'une evaluation numerique d i r e c t e des equations de mouvement des molecules. Ceci permet une meilleure comparaison des r e s u l t a t s expCrimentaux aux modbles q u i decrivent comment l e s forces e f f e c t i v e s sur l e s molecules sont produites 3 p a r t i r d'une e x c i t a t i o n Blectronique i n i t i a l e. Nos calculs reproduisent sans ajustement de parametres quelques aspects c a r a c t e r i s t i q u e s de HIID qui o n t e t e trouves dans des experiences avec des c i b l e s Langmuir-Blodgett, t e l l e s que l a dependance des rendements avec l e s epaisseurs de films e t 1'Bnergie Blectronique perdue.
Publikationsansicht. 8408634. MareNet - ein elektonischer Informationsdienst fuer die Meeresforsc... more Publikationsansicht. 8408634. MareNet - ein elektonischer Informationsdienst fuer die Meeresforschung (2000). Michael Hohlfeld. Abstract. The Concepts MareNet MareNet distributed information service uses the information which ...
Eprint Arxiv Cond Mat 9412121, Dec 30, 1994
We investigate the magnetic properties of small transition metal clusters using a simple statisti... more We investigate the magnetic properties of small transition metal clusters using a simple statistical model, which requires some input data from ab initio spin-density functional calculations. In our study, we consider a thermodynamically equilibrated ensemble of clusters with different structures, spin multiplicities, and ground state energies. We calculate the physical properties of this system by weighting the individual configurations according to the Boltzmann statistics. We find that presence of isomers with very similar ground state energies, yet very different magnetic properties, gives rise to a rich magnetic behaviour of the system which differs significantly from what would be expected for single configurations. We apply the present model to determine the magnetic susceptibility of a cluster ensemble of Langevin paramagnets. Our results show that some of the anomalies in the magnetic behaviour of transition metal clusters might be understood in the framework of our model which is, of course, limited by the extremely high computational effort needed to obtain the input data.
Geometries and energies for H + 3 (H 2) n clusters (n = 0, ..., 11) have been calculated using st... more Geometries and energies for H + 3 (H 2) n clusters (n = 0, ..., 11) have been calculated using standard "ab initio" methods. Up to clusters with n = 6, four different Pople basis sets (DZ, TZ, TZP) have been used in the calculations. For larger cluster sizes, the calculations have been carried out with one basis set (DZ) using the HF/CISD method. We discuss here only the nice counterplay of polarisation effects between the central H + 3 ion and the adsorbed H 2 molecules, which naturally governs both the geometric structure and the energy of the clusters.
ABSTRACT We use Monte Carlo and quaternion molecular dynamics simulations to study the self-assem... more ABSTRACT We use Monte Carlo and quaternion molecular dynamics simulations to study the self-assembly of intriguing structures which form in colloidal suspensions of small magnetite particles. We show that the only stable isomers with few particles, a ring and a chain, can be efficiently interconverted using a magnetizable tip. We propose to use the oscillating dipole field of the tip to locally anneal the aggregates to either a ring in zero field or a chain in nonzero applied field. Typeset using REVT E X Given the present advanced stage of miniaturization, the most promising way to significantly reduce the dimension of devices involves a transition from micro-manufacturing to self-assembly of nanostructures [1]. Inspired by the richness of structures observed in aggregates of magnetic nanoparticles [2,3] and the possibility of their structural transformation [4,5], we propose a hybrid thermodynamic self-assembly technique capable of producing magnetic patterns of unprecedented packing densit...
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Papers by Eberhard R Hilf