Review of the Theoretical Description of Time‐Resolved Angle‐Resolved Photoemission Spectroscopy in Electron‐Phonon Mediated Superconductors

We review recent work on the theory for pump/probe photoemission spectroscopy of electron‐phonon mediated superconductors in both the normal and the superconducting states. We describe the formal developments that allow one to solve the Migdal‐Eliashberg theory in nonequilibrium for an ultrashort laser pumping field, and explore the solutions which illustrate the relaxation as energy is transferred from electrons to phonons. We focus on exact results emanating from sum rules and approximate numerical results which describe rules of thumb for relaxation processes. In addition, in the superconducting state, we describe how Anderson‐Higgs oscillations can be excited due to the nonlinear coupling with the electric field and describe mechanisms where pumping the system enhances superconductivity.     

Injective and Epi-Projective Objects in Categories of Convex Spaces

We give a characterization of injective and epi-projective objects in some categories of convex spaces.     

The Computation of Invariant Fields and a Constructive Version of a Theorem by Rosenlicht

Let G be an algebraic group acting on an irreducible variety X. We present an algorithm for computing the invariant field k(X)^G. Moreover, we give a constructive version of a theorem of Rosenlicht, which says that almost all orbits can be separated by rational invariants. More precisely, we give an algorithm for computing a nonempty open subset of X with a geometric quotient.     

Vergleich von anionenanalysenergebnissen aus der bestimmung mittels ionenchromatographie und klassischen analysenmethoden

(Comparison of analytical results for common anions obtained by ion chromatography and classical methods.)The concentrations of chloride, nitrate, and sulphate were determined in ground-water samples by ion chromatography and by the classical titrimetric, photometric, and gravimetric methods. The results were compared by an orthogonal regression procedure. The criteria established and the tests of the confidence intervals of the orthogonal regression function indicate that the results obtained by the different analytical methods are similar for chloride and sulphate but not for nitrate.     

Photorefractive properties of ion-implanted waveguides in strontium barium niobate crystals

0.61 Ba_0.39Nb₂O₆, SBN61), either by proton or helium ion implantation. Proton-implanted samples show a large increase of dark conductivity that reduces or even prevents the recording of refractive index gratings. For waveguides formed by helium implantation this effect is absent, and they can be used for efficient holographic recording. Photorefractive properties of the waveguides are investigated by two-beam coupling. After implantation with 2.0 MeV He⁺ and doses of (0.5-5)×10¹⁵ cm^-2, the samples have to be polarized again, because heating or charge effects at the crystals surface during the implantation process decreases or even reverses the effective electrooptic coefficients in the waveguiding layer. For repoled samples, we find logarithmic gain coefficients of up to 45 cm^-1 with time constants for the build-up of the purely π/2-shifted refractive index grating of the order of 1 ms for the blue lines of an Ar⁺ laser. Photoconductivity depends nonlinearly on light intensity with an exponent x≈0.55. With increasing implanted helium dose, both electronic and nuclear damage of the waveguiding layer grows, and the photorefractive properties of the waveguides are considerably degraded. Received: 20 February 1997/Revised version: 1 May 1997     

A simple computer program for high resolution gamma-ray spectra

A computer program is presented, which locates peaks in high-resolution γ-ray spectra and determines their content. The program has been written in Basic; ‘translations’ have been made into Fortran and Algol. For detailed information the reader is referred to the original TNO Report CL 69/137.     

A simple and sensitive assay for the quantitative analysis of paclitaxel in human and mouse plasma and brain tumor tissue using coupled liquid chromatography and tandem mass spectrometry

The development and validation of an assay for the determination of paclitaxel in human plasma, human brain tumor tissue, mouse plasma and mouse brain tumor tissue is described. Paclitaxel was extracted from the matrices using liquid-liquid extraction with tert-butyl methyl ether, followed by chromatographic analysis using an alkaline eluent. Positive ionization electrospray tandem mass spectrometry was performed for selective and sensitive detection. The method was validated according to the FDA guidelines on bioanalytical method validation. Validation results indicate that calibration standards in human plasma can be used to quantify paclitaxel in all tested matrices. In human samples, the validated range for paclitaxel was from 0.25-1000 ng ml(-1) using 200 microl plasma aliquots and from 5 to 5000 ng g(-1) using 50 microl tumor homogenate aliquots (0.2 g tissue ml(-1) control human plasma). In mice, the ranges were 1-1000 ng ml(-1) and 5-5000 ng g(-1) using 50 microl of mouse plasma and 50 microl of tumor homogenate aliquots (0.2 g tissue ml(-1) control human plasma), respectively. The method can be applied to studies generating only small sample volumes (e.g. mouse plasma and tumor tissue), but also to studies in human plasma requiring a lower limit of quantitation. The assay was applied successfully to several studies with both human and mouse samples.     

Landing of size-selected Agn+ clusters on single crystal TiO2 (110)-(1x1) surfaces at room temperature

Mass-selected Ag(n) (+) (n=1,2,3) clusters with impact energy less than 2 eV per atom were deposited from the gas phase onto rutile titania (110)-(1x1) single crystal surfaces at room temperature and imaged using ultra-high vacuum scanning tunneling microscopy. Upon reaching the surface, Ag monomers sintered to form three-dimensional islands of approximately 50 atoms in size, with an average measured height of 7.5 A and diameter of 42 A. This suggests that the monomers are highly mobile on the titania surface at room temperature. Dimers also sintered to form large clusters upon deposition, approximately 30 atoms in size, with an average height of 6.2 A and diameter of 33 A. Clusters formed from monomer deposition appeared approximately three times more frequently at step edges than clusters formed from dimer deposition, indicating that the surface mobility of deposited monomers is higher than that of deposited dimers. In sharp contrast to the deposition of monomers and dimers, the deposition of trimers resulted in a high density of very small clusters on the order of a few atoms in size, indicative of intact trimers on the surface, implying that deposited trimers have very limited mobility on the surface at room temperature.     

Dünnschichtchromatographie an Salzen von Heteropolysäuren

Zusammenfassung In Fortsetzung einer früheren Arbeit wurde die Verwendbarkeit von Ammoniumphosphordodekamolybdat (APM), Ammoniumgermanododekamolybdat (AGM), Oxingermanododekamolybdat (OGM), Pyridingermanododekamolybdat (PGM), Oxinsilicododekamolybdat (OSM) und Pyridinsilicododekamolybdat (PSM) für Dünnschichtchromatographie untersucht und die Abhängigkeit derR _f -Werte der Alkalimetallionen von der Laufmittelkonzentration (Ammoniumnitrat und Wasser) bestimmt. Gleichzeitig wurden Vorversuche angestellt, eine spezifische Abtrennung des Cäsiums von den Spaltprodukten⁹⁵Zr/⁹⁵Nb,¹⁰⁶Ru,⁹⁰Sr/⁹⁰Y und¹⁴⁴Ce durchzuführen.

---

Summary As continuation of an earlier study, ammonium phosphododeoa molybdate (APM), ammonium germanododecamolybdate (AGM), oxinegerdodecamolybdate (OGM), pyridinegermanododecamolybdate (PGM), oxininesilicododecamolybdate (OSM), and pyridinesilicododecamolybdate (PSM) were investigated for thin layer chromatography and the relation of theR _f -values of the alkali metal ions to the concentration of the carrier concentration (ammonium nitrate and water) was determined. At the same time, preliminary studies were made with respect to a specific separation of cesium from the fission products⁹⁵Zr/⁹⁵Nb,¹⁰⁶Ru,⁹⁰Sr/⁹⁰Y and¹⁴⁴Ce.

---

Résumé Comme suite à une publication antérieure, on a étudié les possibilités d'application en chromatographie en couche mince du phosphododécamolybdate d'ammonium (APM), du germanidodécamolybdate d'ammonium (AGM), du germanidodécamolybdate d'oxinium (OGM), du germanidodécamolybdate de pyridinium (PGM), du silicomolybdate d'oxinium (OSM) et du silicododécamolybdate de pyridinium, en déterminant la dépendance des valeurs duR _f des ions métalliques alcalins avec la concentration de l'éluant (nitrate d'ammonium et eau). On a commencé simultanément l'étude de la séparation spécifique du césium d'avec les produits de fission⁹⁵Zr/⁹⁵Nb,¹⁰⁶Ru,⁹⁰Sr/⁹⁰Y et¹⁴⁴Ce.

---

---

Herrn Prof. Dr.A. A. Benedetti-Pichler mit herzlichen Wünschen zum 70. Geburtstag gewidmet.