Die ma?analytische Bestimmung der h?heren Oxyde des Bleis Mangans mit Titantrichlorid

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Elektrische und thermische Eigenschaften von Salzlösungen

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Heizwertbestimmung fester Brennstoffe

Ohne Zusammenfassung     

67Zn Mössbauer study of Zn metal and Cu−Zn alloys at high pressure

A high pressure Mössbauer spectrometer for the 93.3keV resonance in⁶⁷Zn has been used to investigate Zn metal and two Cu?Zn alloys with Zn concentrations of 41.9at% and 48.0at% at 4.2K and pressures up to ～58kbar. For Zn metal the c/a-ratio plays an important role to describe the change of the Mössbauer parameters with pressure. Most striking is the increase of the recoil-free fraction by a factor of ～3. In the brass alloys a new phase is observed at 4.2K and high pressures which we tentatively identify with a martensitic α₁-phase.     

High pressure studies of actinide intermetallics

Hyperfine Interactions - Magnetic properties of NpOs2,NpAl2. NpCo2Si2, NpAs, and NpSn3 are investigated by high pressure Mössbauer spectroscopy using the 60 keV transition in237Np. A wide...     

Properties of silver halide core-clad fibers and the use of fiber bundle for thermal imaging

Optical infrared (IR) fibers with core-clad structure are of great importance because they have better qualities than unclad fibers for most IR fiber applications, especially in CO₂ laser power delivery and radiometry. We have fabricated core-clad polycrystalline silver halide optical fibers with different compositions and core diameters, and although their loss is still higher than that of unclad fibers, they already have many advantages and new capabilities. The behavior of the scattering loss along these fibers and other optical properties was measured and compared with that of unclad silver halide fibers. We show that the higher loss of clad fibers results mainly from excessive scattering. The improvement in the process of fabricating clad fibers enabled the production of new elements such as single-mode fibers (SMFs) and fiber bundles for thermal imaging.     

Dimeric Cyclodextrin Carriers with High Binding Affinity to Porphyrinoid Photosensitizers

The aim of our investigation was to develop carrier systems for an application of inert drugs in photodynamic cancer therapy. -Cyclodextrin dimers linked at their primary and secondary faces by spacers of varying lengths were synthesized as carrier systems. The binding constants of the inclusion complexes of these cyclodextrin dimers and porphyrinoid photosensitizers were determined by competitive spectrofluorometry. Particularly the secondary face linked dimers exhibited extremely high binding constants with values of 106-107 L/mol. Theoretical studies were carried out on these inclusion complexes to confirm the influence of spacer length and connecting side on complex stability.     

The effect of low-temperature electron irradiation on the transition temperature of YBa2Cu3O7−δ superconductors

Measurements of the complex susceptibility =–i of electron-irradiated YBa₂Cu₃O_7– show a strong influence of the electron irradiation dose, ·t on the transition temperatureT _c . For irradiation doses of ·t=2.2·10¹⁹ e^–/cm² we find a damage rate of T _c /(·t)=–1.6·10^–19 K/(e^–/cm²). It is assumed that the decrease ofT _c is mainly a bulk effect due to the production of atomic defects like vacancies and interstitials in the Cu–O–Cu chains and in the basal planes of the unit cells.     

A comparison of methods for the determination of the dating-nuclides210Pb and226Ra

Lead-210 is often used to date recent (100 y) environmental samples. Three different methods for its determination are compared:²¹⁰Pb -counting with a low level proportional counter,²¹⁰Pb -spectroscopy and²¹⁰Po -spectroscopy. Agreement within analytical errors was found for the three methods in two sediment cores from Lake Zurich, Switzerland and in IAEA SD-A-1 deep sea reference material. For²¹⁰Po -spectroscopy, the detection and determination limit is an order of magnitude lower than these for the other methods. Methods for the determination of²²⁶Ra are also discussed. Measurements on low level proportional counters are difficult to interpret and not suitable for routine work. A better way to measure²²⁶Ra is -spectroscopy of colloidal Ba(Ra)SO₄.