84 research outputs found

    X ray induced sample damage at the Mn L edge a case study for soft X ray spectroscopy of transition metal complexes in solution

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    X ray induced sample damage can impede electronic and structural investigations of radiation sensitive samples studied with X rays. Here we quantify dose dependent sample damage to the prototypical MnIII acac 3 complex in solution and at room temperature for the soft X ray range, using X ray absorption spectroscopy at the Mn L edge. We observe the appearance of a reduced MnII species as the X ray dose is increased. We find a half damage dose of 1.6 MGy and quantify a spectroscopically tolerable dose on the order of 0.3 MGy 1 Gy 1 J kg 1 , where 90 of MnIII acac 3 are intact. Our dose limit is around one order of magnitude lower than the Henderson limit half damage dose of 20 MGy which is commonly employed for protein crystallography with hard X rays. It is comparable, however, to the dose limits obtained for collecting un damaged Mn K edge spectra of the photosystem II protein, using hard X rays. The dose dependent reduction of MnIII observed here for solution samples occurs at a dose limit that is two to four orders of magnitude smaller than the dose limits previously reported for soft X ray spectroscopy of iron samples in the solid phase. We compare our measured to calculated spectra from ab initio restricted active space RAS theory and discuss possible mechanisms for the observed dose dependent damage of MnIII acac 3 in solution. On the basis of our results, we assess the influence of sample damage in other experimental studies with soft X rays from storage ring synchrotron radiation sources and X ray free electron laser

    Crossing the Dripline to 11N Using Elastic Resonance Scattering

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    The level structure of the unbound nucleus 11N has been studied by 10C+p elastic resonance scattering in inverse geometry with the LISE3 spectrometer at GANIL, using a 10C beam with an energy of 9.0 MeV/u. An additional measurement was done at the A1200 spectrometer at MSU. The excitation function above the 10C+p threshold has been determined up to 5 MeV. A potential-model analysis revealed three resonance states at energies 1.27 (+0.18-0.05) MeV (Gamma=1.44 +-0.2 MeV), 2.01(+0.15-0.05) MeV, (Gamma=0.84 +-$0.2 MeV) and 3.75(+-0.05) MeV, (Gamma=0.60 +-0.05 MeV) with the spin-parity assignments I(pi) =1/2+, 1/2- and 5/2+, respectively. Hence, 11N is shown to have a ground state parity inversion completely analogous to its mirror partner, 11Be. A narrow resonance in the excitation function at 4.33 (+-0.05) MeV was also observed and assigned spin-parity 3/2-.Comment: 14 pages, 9 figures, twocolumn Accepted for publication in PR

    Lattice QCD at finite temperature: a status report

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    Karsch F. Lattice QCD at finite temperature: a status report. Zeitschrift für Physik, C: Particles and Fields. 1988;38(1-2):147-155.We analyze the status of numerical simulation of QCD at finite temperature. Emphasis is put on quantitative predictions emerging from lattice calculations that may be tested in heavy ion experiments. Recent results on the chiral phase transition, thermodynamics of the quark gluon plasma phase and various screening lengths are discussed. Presented at the 6th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions-Quark Matter 1987, 24–28 August 1987, Nordkirchen, Federal Republic of Germany

    Subjective face recognition difficulties, aberrant sensibility, sleeping disturbances and aberrant eating habits in families with Asperger syndrome

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    BACKGROUND: The present study was undertaken in order to determine whether a set of clinical features, which are not included in the DSM-IV or ICD-10 for Asperger Syndrome (AS), are associated with AS in particular or whether they are merely a familial trait that is not related to the diagnosis. METHODS: Ten large families, a total of 138 persons, of whom 58 individuals fulfilled the diagnostic criteria for AS and another 56 did not to fulfill these criteria, were studied using a structured interview focusing on the possible presence of face recognition difficulties, aberrant sensibility and eating habits and sleeping disturbances. RESULTS: The prevalence for face recognition difficulties was 46.6% in individuals with AS compared with 10.7% in the control group. The corresponding figures for subjectively reported presence of aberrant sensibilities were 91.4% and 46.6%, for sleeping disturbances 48.3% and 23.2% and for aberrant eating habits 60.3% and 14.3%, respectively. CONCLUSION: An aberrant processing of sensory information appears to be a common feature in AS. The impact of these and other clinical features that are not incorporated in the ICD-10 and DSM-IV on our understanding of AS may hitherto have been underestimated. These associated clinical traits may well be reflected by the behavioural characteristics of these individuals

    Investigation of the alpha-cluster structure of Ne-22 and Mg-22

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    10 pages, 2 tables, 10 figures.--PACS nrs.: 21.10.-k; 24.30.-v; 27.30.+tAn excitation function for resonance elastic scattering of alpha particles on O-18 and Ne-18 was measured using the method of inverse geometry with a very thick target. Spectroscopic information was obtained for 23 levels in the excitation energy region from 11.9 to 13.7 MeV in Ne-22. Twelve of them are new. General features of a-cluster bands in Ne-22 are analyzed in the framework of the potential model with a deep potential well. Predictions for the 11(-) level in Ne-22, as well as for the isotopic shift of the cluster levels in Mg-22, are given. Evidence is presented that new perspectives on the study of nuclear structure and nuclear spectroscopy can be obtained in complimentary measurements of alpha-cluster states in mirror Nnot equalZ nuclei.This work was supported by NSF Grant Nos. PHY99-01133 and PHY02-030099, RFBR Grant No. 00-02-17401, U.S. DOE Grant No. DE-FG03-93ER40773, and European Community-Access to Research Infrastructure action of the Improving Human Potential Programme, Contract No.HPRI-CT-1999-00110.Peer reviewe

    Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine

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    [This corrects the article DOI: 10.1186/s13054-016-1208-6.]

    High-frequency response of polymeric light-emitting diodes

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    The frequency dependence of alternating-current polymeric light-emitting diodes has been studied. Langmuir-Blodgett (LB) films of poly(3-hexylthiophene) have been used as the active emitting material sandwiched between LB films of emeraldine base polyaniline to form the device. We have shown that by reducing the thickness of the emitting layer using the LB deposition technique, one can increase the high-frequency operating limit of the device. From the -3 dB frequency, we have calculated the carrier mobility in the emitting polymer layer, and compared it with the Poole-Frenkel model. The electroluminescence and photoluminescence spectra have been studied

    Frequency response of molecularly thin alternating current light-emitting diodes

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    The frequency response of molecularly thin alternating-current polymeric light-emitting diodes has been studied. Langmuir-Blodgett (LB) films of poly(3-hexylthiophene) (PHT) were used as the active emitting material and the device was formed by sandwiching PHT films between LB films of emeraldine base polyaniline. As a step towards molecular electronic devices, we have shown that even two molecular layers of PHT ( ≈ 6 nm) are sufficient for light emission. The high frequency operation limit of the device has been discussed in terms of a charge accumulation process at the polymer-polymer interface. The electroluminescence (EL) spectra of different structures have been compared with corresponding photoluminescence spectra. A significant blueshift in EL has been observed in thinner structures and its origin has been discussed

    Electric field redistribution and electroluminescence response time in polymeric light-emitting diodes

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    The electric field redistribution due to injected and trapped charge carriers in Langmuir-Blodgett (LB) films of poly(3-hexylthiophene) (P3HT) sandwiched between indium tin oxide and aluminum (Al) electrodes as function of applied voltage has been studied using charge collection measurements by the time-of-flight technique. For μ tE<d (the drift distance shorter than the interelectrode distance) the amount of the collected photocharge is a function of electric field near the Al electrode and has been used to probe the time evolution of it. The response time for the field to redistribute inside the P3HT LB film was found to be of the order of 5-200 μs, in good agreement with the delay time observed in time-resolved electroluminescence measurements in light-emitting diodes (LED) of similar LB films. We suggest a model for the response times in organic LEDs based on these results
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