A simple transition-locked and polarization-forced multi-line oscillator for high-power CO2-laser systems

Employing injection-locking techniques an oscillator configuration was found comprising in a simple way all the features required for fusion directed high-power CO₂ laser systems. The oscillator provides emission in single axial modes on rotational transitions which can be freely selected by feeding fluencies of a few mW/cm² at the particular transition into the oscillator cavity. In the same way simultaneous emission on selectable lines can be achieved. By the same principle the oscillator can be forced to emit in any orientation of polarization. The set up is relatively simple, the alignment rather uncritical, and the operation reliable. Gaussian-shaped nanosecond pulses with low forepulse power are produced with the help of a pulse cutter and saturable multiline absorber. The set up is described and its features are demonstrated by measurements. This research was carried out under the auspices of the “Sonderforschungsbereich Nr. 162 Plasmaphysik Bochum/Jülich”.     

Trigonal-prismatic CuII6-pyrazolato cages: structural and electrochemical study, evidence of charge delocalisation

Hexanuclear CuII-complexes of formula PPN[Cu6(micro3-O)2(micro-4-Rpz)6(micro-4-R'-3,5-Ph2pz)3] have been structurally characterized and the effect of pyrazole substituents on their two consecutive one-electron oxidation processes, leading to (possibly delocalised) mixed-valent products, has been probed by cyclic voltammetry.     

A new high luminosity UHV orange type magnetic spectrometer used for depth selective Mössbauer spectroscopy

A new magnetic spectrometer of the orange type has been built for energies up to 45 keV. Its features are: ·?Transmission: 20% of 4π ·?Relative momentum resolution: 0.1 to 1%, ·?Energy band width: ΔE/E = ± 4% For Auger Electron Spectroscopy (AES) a combination with an electrostatic retardation field around the sample will provide an even higher resolution. For depth selective conversion electron Mössbauer spectroscopy (DCEMS) the exceptional high effective luminosity of the ultrahigh vacuum (UHV) orange spectrometer allows the analysis of non-enriched samples in reasonable time without loss in depth resolution. The UHV was realized by a differentially evacuated double chamber system made of an aluminium alloy using Viton gaskets. The inner part can be heated to 150°?C.     

Synthesis and complex formation of 2-ammoethylthioacet(N-2-pyridylmethyl)amide

Summary A new ligand, 2-aminoethylthioacet(N-2-pyridylmethyl)amide was synthesized. The complex formation of the ligand with Cu^II, Co^II and Co^III ions and that of the carbobenzoxy derivative of the ligand with Cu^II ions has been investigated. Structures are proposed for all complexes isolated and the factors influencing metal-sulphur bond formation in the complexes discussed.     

Reactions of stabilizer compounds. III. Oxidative reactions of some 2′-hydroxy-2-phenylbenzotriazole light stabilizers in the AIBN-initiated autoxidation of cumene

Oxidative decay of number of commercially important 2′-hydroxy-2-phenylbenzotriazole light stabilizers during the AIBN-initiated autoxidation of cumene at 65°C is described. The reactivity of the hydroxyphenylbenzotriazoles studied increased in the order 2-(2′-hydroxy-5′-methyl)phenylbenzotriazole (Ia) < 2-(2′-hydroxy-3′,5′ -di-tert-pentyl)phenylbenzotriazole (Ie) < 5-chloro-2-(3′,5′-di-tert-butyl-2′-hydroxy)phenylbenzotriazole (Ic) < 5-chloro-2-(3′-tert-butyl-2′-hydroxy-5′-methyl)phenylbenzotriazole (Ib). The major product from the reaction of Ib was identified as the cumylperoxycyclohexa-2,5-dienone (III). The possible occurrence of these reactions during the degradation of stabilized polymers is discussed.     

Reduced magnetic hyperfine field at the surface of α-Fe2O3 and FeBO3 single crystals

The surface magnetic ordering of an α-⁵⁷Fe₂O₃ and ⁵⁷FeBO₃ single crystal was studied by Depth Selective Conversion Electron Mössbauer Spectroscopy (DCEMS). The depth selective Mössbauer data of ⁵⁷FeBO₃ up to the Néel temperature (T _N = 348.35 K) reveal the coexistence of the canted antiferromagnetic bulk phase and a magnetic surface phase that shows time relaxation. Both phases are separated by a wall (interim layer) and the thickness of the magnetic surface layer increases as the crystal is heated to T _N.     

Metal-organotetraphosphonate inorganic-organic hybrids: crystal structure and anticorrosion effects of zinc hexamethylenediaminetetrakis(methylenephosphonate) on carbon steels

The synthesis and structural characterization of the first polymeric M-HDTMP organic-inorganic hybrids are described [M = Zn2+, Ca2+; HDTMP = hexamethylenediaminetetrakis(methylenephosphonate)]. The 3D crystal structure of the Zn2+ analogue [Zn(HDTMP) x H2O] is described. The Zn center is found in a distorted octahedral environment of phosphonate oxygens. There is a long Zn...O interaction (2.622 A) originating from a protonated -P-OH group. Synergistic combinations of Zn2+ and the tetraphosphonate are found to form films that protect against the corrosion of carbon steels.