Zeeman transitions in deuterium atoms induced by ultra-relativistic electrons

We present data showing hyperfine transitions in an atomic deuterium beam induced by the (476 MHz) radio-frequency field of a 704 MeV electron beam in a storage ring. A polarized deuterium beam, produced in an atomic beam source, was crossed with a stored electron beam and analyzed with a Breit--Rabi polarimeter. Electron-beam induced transitions were singled out by injecting different combinations of hyperfine states. Transition probabilities as high as 70% were measured at large currents (~ 100 mA). All possible deuterium transitions for a radio-frequency of 476 MHz were observed. In addition, a 1--6 transition resulting from the first harmonic (952 MHz) was observed. The effects of these transitions are of general importance for the polarized internal target technique applied in nuclear and particle physics experiments. The data are reasonably described by numerical estimates. The observed mechanism can be exploited to create nuclear polarized atoms when injecting electron polarized atoms with no net nuclear polarization into a storage cell. However, when nuclear polarized atoms are injected, care should be taken to avoid this mechanism, since it would result in depolarization of the atoms. The studies enabled us to choose the magnetic guide field during our spin-dependent electron--deuteron scattering experiments, such that electron-beam induced depolarizing effects were avoided. This revised version was published online in July 2006 with corrections to the Cover Date.     

On the behaviour of rubberlike materials in compression and shear

Summary The mechanical behaviour of rubberlike materials is modelled in a phenomenological approach using a strain-energy formulation. Nonhomogeneous shear experiments on solid rubber specimens have been carried out as well as simple elongation tests on the same rubber compound. The elongation tests have been used to determine the model constants. By a comparison between experiment and numerical simulation of the nonhomogeneous shear test the predictive capabilities of the Mooney-Rivlin, the Ogden and the Besseling model have been assessed for compression-shear deformation paths. An analytical study explains the numerically observed behaviour.

---

Über das Verhalten von Gummimaterialien unter Druck und Schubverformungen

Übersicht Das mechanische Verhalten von Gummimaterialien wird phänomenologisch modelliert unter Anwendung einer Formänderungsenergiefunktion. Es sind nicht-homogene Schubversuche auf dreidimensionale Versuchsproben aus Gummi so wie auch einfache Verlängerungsversuche auf Gummiproben der gleichen Zusammenstellung durchgeführt worden. Die Verlängerungsversuche sind durchgeführt worden um die Stoffkennwerte feststellen zu können. In einer Vergleichung zwischen dem Experiment und der numerischen Simulation von nicht-homogenen Schubversuchen ist die Genauigkeit des Mooney-Rivlinschen Modells, des Ogdenschen Modells und des Besselingschen Modells für kombinierte Druck-Schubverformungen festgestellt worden. In einem analytischen Studium wird das numerisch betrachtete Verhalten auseinandergesetzt.

     

High-performance liquid chromatographic determination of morphine and its 3- and 6-glucuronide metabolites: improvements to the method and application to stability studies

Improvements to previously reported methods for the determination of morphine, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) in human plasma are described. The improved methods involve the use of a solid-phase extraction cartridge and a chromatographic system which uses paired-ion reversed-phase high-performance liquid chromatography with a radially compressed column. Only one cartridge is used to prepare each sample for chromatography and each cartridge may be used for at least fourteen 1-ml plasma samples. The recovery is greater than 85%. The improvements to the method of sample pretreatment and in the chromatographic conditions have allowed determination of morphine, M3G and M6G in human plasma down to 13.3 nmol/l (coefficient of variation = 9.3%), 108 nmol/l (6.6%) and 41 nmol/l (6.7%), respectively, using ultraviolet detection alone. It was shown that all three compounds were stable in plasma for up to 101 weeks when stored at -20 degrees C.     

KINETICS OF LUMINESCENCE QUENCHING IN MICELLAR ASSEMBLIES INCLUDING EXCHANGE OF PROBE and QUENCHER*

The luminescence decay of excited probes in micelles in the presence of a Poisson distribution of quenchers is considered under conditions where both probe and quencher within the lifetime of the excited probe may exchange between the micelles. Analytical and numerical results show that the luminescence decay can be expressed by a generalized self convolution product of a multiexponential decay function.     

Scroll codes

We study algebraic geometric codes obtained from rational normal scrolls. We determine the complete weight hierarchy and spectrum of these codes.      

Electromagnetic properties of strange baryons in a relativistic quark model

We present some of our results for the electromagnetic properties of excited Σ hyperons, computed within the framework of the Bonn constituent-quark model, which is based on the Bethe-Salpeter approach. The seven parameters entering the model are fitted against the best-known baryon masses. Accordingly, the results for the form factors and helicity amplitudes are genuine predictions. We compare with the scarce experimental data available and discuss the processes in which Σ ^*'s may play an important role.     

Using Inquiry to Improve Pedagogy through K‐12/University Partnerships

This article focuses on the impact a collaborative project between university graduate fellows and K‐12 classroom teachers had on improved pedagogy in the classroom and in the future at the university. Nine teams participated in a yearlong professional development project to improve pedagogy and communication skills of the participants. This study shows that the participants, the fellows and the K‐12 teacher partners, made changes in planning, implementation, and even motivation for using inquiry‐based methods in their classroom. External observations of the teams further support the individuals' claims of improved pedagogy using inquiry and impact on student conceptual understanding. The Horizon Classroom Observation instrument was used for these observations. The teams showed an overall increase in scores, as well as overall effective and exemplarily implementation of their planning. The program design, the implementation, and the results of this three‐year study will be elaborated in this article.