Parities of strong dipole ground state transitions in88Sr

By on-line mass separation and subsequent gamma and electron decay-spectroscopy at very low energy, two new isomers,^124mCs (T_1/2=6.3 ±0.3 seconds) and^127mBa (T_1/2=1.9±0.2 seconds) have been identified.     

Nuclear and atomic activation with heavy ion beams

Heavy ion activation has been studied as a method for determining hydrogen. The reactions used [e.g.¹H(⁷Li, n)⁷Be] are the “inverse” of well known reactions [e.g.⁷Li(p, n)⁷Be]. Nuclear activation parameters for the ion beams of interest (⁷Li²⁺,¹⁰B²⁺) have been studied. The analytical feasibility is demonstrated with the determination of hydrogen in titanium at the 100 and 30 ppm levels with relative precisions of 8 to 10%. Detection limits in titanium are in the 0.1 to 0.5 ppm range. Heavy ion bombardment is also accompanied by the emission of characteristic X-rays (“atomic” activation). The parameters governing X-ray emission and background production have been investigated. Experimental K and L X-ray yields from thick targets have been measured for many elements excited by Oⁿ⁺ beams of 0.5 to 7 MeV/amu and Kr⁷⁺ beams of 0.5 to 1 MeV/amu. The simultaneous determination of trace elements at levels of 10 to several 100 ppm in microsamples (∼10⁻⁵ g) is demonstrated on biological specimens. K and L X-ray yields and corresponding detection limits have also been measured with the⁷Li²⁺ and¹⁰B²⁺ beams used for the nuclear activation of hydrogen. With these beams (∼6 MeV/amu) simultaneous nuclear and atomic activation is possible, yielding an unusual multielement trace analysis capability covering hydrogen and medium and high Z elements.     

Internal structure rebuilding reactions of crystalline and amorphous solids

Structural mechanism of the internal thermal reactions of dehydration and dehydroxylation as of solids well as crystallization of their amorphous products and glasses are considered. They are multi-stage processes, realized through small translative displacements of polymerized anion network elements and diffusional shift of cations. It is the way to equilibrium state of the lowest energy consumption and the least energetic barrier to overcome.

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Zusammenfassung Es werden Strukturmechanismen von internen thermischen Reaktionen von Dehydratation und Dehydroxylierung sowie der Kristallisierung der entstehenden amorphen Reaktionsprodukte betrachtet. Dabei handelt es sich um mehrstufige Prozesse, die über kleine translative Verschiebungen von polimerisierten Elementen des Anionennetzwerkes und durch Diffusionsverschiebung von Kationen ablaufen. Dies ist der Weg zum Gleichgewichtszustand mit dem geringsten Energieverbrauch und der niedrigsten, zu überwindenden Energiebarriere.

     

Calibration standards for composition-depth profiles of non-stoichiometric titanium nitride coatings

Five different TiN_x coatings have been deposited on steel substrates by reactive magnetron sputtering. A quantitative analysis was carried out in two ways. The coatings were initially analysed by GDOS and after removing the coatings from the substrates and digesting the TiN_x powder, nitrogen was quantified by the Kjeldahl technique and titanium by AAS. A comparison of the results shows that AAS and Kjeldahl results correlate very well, whereas GDOS results deviate from these two methods systematically.