1,325 research outputs found
The coil-globule transition of confined polymers
We study long polymer chains in a poor solvent, confined to the space between
two parallel hard walls. The walls are energetically neutral and pose only a
geometric constraint which changes the properties of the coil-globule (or
"-") transition. We find that the temperature increases
monotonically with the width between the walls, in contrast to recent
claims in the literature. Put in a wider context, the problem can be seen as a
dimensional cross over in a tricritical point of a model. We roughly
verify the main scaling properties expected for such a phenomenon, but we find
also somewhat unexpected very long transients before the asymptotic scaling
regions are reached. In particular, instead of the expected scaling exactly at the (-dependent) theta point we found that increases
less fast than , even for extremely long chains.Comment: 5 pages, 6 figure
Polymer-Based Batteries â Flexible and Thin Energy Storage Systems
Batteries have become an integral part of everyday lifeâfrom small coin cells to batteries for mobile phones, as well as batteries for electric vehicles and an increasing number of stationary energy storage applications. There is a large variety of standardized battery sizes (e.g., the familiar AAâbattery or AAAâbattery). Interestingly, all these battery systems are based on a huge number of different cell chemistries depending on the application and the corresponding requirements. There is not one single battery type fulfilling all demands for all imaginable applications. One battery class that has been gaining significant interest in recent years is polymerâbased batteries. These batteries utilize organic materials as the active parts within the electrodes without utilizing metals (and their compounds) as the redoxâactive materials. Such polymerâbased batteries feature a number of interesting properties, like high power densities and flexible batteries fabrication, among many more
Precision mass measurements of radioactive nuclei at JYFLTRAP
The Penning trap mass spectrometer JYFLTRAP was used to measure the atomic
masses of radioactive nuclei with an uncertainty better than 10 keV. The atomic
masses of the neutron-deficient nuclei around the N = Z line were measured to
improve the understanding of the rp-process path and the SbSnTe cycle.
Furthermore, the masses of the neutron-rich gallium (Z = 31) to palladium (Z =
46) nuclei have been measured. The physics impacts on the nuclear structure and
the r-process paths are reviewed. A better understanding of the nuclear
deformation is presented by studying the pairing energy around A = 100.Comment: 4 pages and 4 figures, RNB7 conf. pro
Beobachtungsstudien im Rahmen eines naturheilkundlichen Klinikverbunds :Teil I: Methoden und Ăbersicht der Ergebnisse in den beteiligten Kliniken
Background: In Germany a considerable number of in-patient facilities offer complementary medicine in addition to conventional care. In this study we aimed to describe patient characteristics, diagnostics, therapy and outcomes of four such in-patient facilities. Methods: 2835 consecutive in-patients admitted to two private hospitals with an emphasis on complementary medical cart, one private hospital for traditional Chinese medicine, and the Department of Complementary Medicine of a public district hospital participated in a prospective observational (cohort) study with 12 months follow-up. Sociodemographic characteristics, diagnoses, duration of disease, type and frequency of therapeutic interventions, intensity of complaints, assessment of therapeutic success, and quality of life were documented. Results: Patients of the observed hospitals were mostly female (66%-80% in the four hospitals) and a high proportion was chronically ill (31%-62% with a disease history longer than 5 years). The frequency of single diagnoses varied strongly between the four hospitals, however, chronic pain syndromes were very frequent in all. Complementary care always included a large number of different therapeutic methods whose combination varied with different diagnoses and between the hospitals. At discharge, 57%-73% of patients rated the therapeutic success as good or very good, Follow-up rates were satisfactory only in two of the four hospitals. After 12 months 51%-64% of the responding patients still rated the success as good or very good. Conclusions: In the observed hospitals mainly chronically ill patients are treated with highly complex combinations of a large variety of complementary therapies. A majority of patients seems to be satisfied by the treatment. A major methodological problem in the interpretations of patient outcomes are the partly low followup rates
Separated Oscillatory Fields for High-Precision Penning Trap Mass Spectrometry
Ramsey's method of separated oscillatory fields is applied to the excitation
of the cyclotron motion of short-lived ions in a Penning trap to improve the
precision of their measured mass. The theoretical description of the extracted
ion-cyclotron-resonance line shape is derived out and its correctness
demonstrated experimentally by measuring the mass of the short-lived Ca
nuclide with an uncertainty of using the ISOLTRAP Penning
trap mass spectrometer at CERN. The mass value of the superallowed beta-emitter
Ca is an important contribution for testing the conserved-vector-current
hypothesis of the electroweak interaction. It is shown that the Ramsey method
applied to mass measurements yields a statistical uncertainty similar to that
obtained by the conventional technique ten times faster.Comment: 5 pages, 4 figures, 0 table
TACTIC : The TRIUMF Annular Chamber for Tracking and Identification of Charged particles
An in-depth characterization of the TACTIC detector was performed using data from a 148Gd alpha source and some test runs with a stable ion beam. The detector is an active target time-projection chamber with a blind central region for maximizing beam tolerance and GEM-based electron amplification, equipped with a modern digitizing data acquisition system allowing the recording of full signals. The system was developed to study the reaction 8Li(α,n)11B, which is important for bridging the mass 8 gap in scenarios of low 4He density like Inhomogeneous Big Bang Nucleosynthesis and the production of r-process seeds in supernovae. Both energy resolution and tracking accuracy were found to agree with theoretical predictions and Geant4 simulations. The 8Li beam rate capability of the system is predicted to be of the order of 105s-1, several orders of magnitude higher than most previous measurements of the same reaction, while still maintaining a high detection efficiency of 70% to 80 %
Beta-decay branching ratios of 62Ga
Beta-decay branching ratios of 62Ga have been measured at the IGISOL facility
of the Accelerator Laboratory of the University of Jyvaskyla. 62Ga is one of
the heavier Tz = 0, 0+ -> 0+ beta-emitting nuclides used to determine the
vector coupling constant of the weak interaction and the Vud quark-mixing
matrix element. For part of the experimental studies presented here, the
JYFLTRAP facility has been employed to prepare isotopically pure beams of 62Ga.
The branching ratio obtained, BR= 99.893(24)%, for the super-allowed branch is
in agreement with previous measurements and allows to determine the ft value
and the universal Ft value for the super-allowed beta decay of 62Ga
A recoil separator for nuclear astrophysics SECAR
A recoil separator SECAR has been designed to study radiative capture reactions relevant for the astrophysical rp-process in inverse kinematics for the Facility for Rare Isotope Beams (FRIB). We describe the design, layout, and ion optics of the recoil separator and present the status of the project
Restoration of the N=82 Shell Gap from Direct Mass Measurements of Sn
A high-precision direct Penning trap mass measurement has revealed a 0.5-MeV deviation of the binding energy of Sn from the currently accepted value. The corrected mass assignment of this neutron-rich nuclide restores the neutron-shell gap at N=82, previously considered to be a case of âshell quenching.â In fact, the new shell gap value for the short-lived Sn is larger than that of the doubly-magic Ca which is stable. The N=82 shell gap has considerable impact on fission recycling during the process. More generally, the new finding has important consequences for microscopic mean-field theories which systematically deviate from the measured binding energies of closed-shell nuclides
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