Phases and reactions in the Li x Mn3−x O y system

The dissociation and oxidation processes occurring in Li _x Mn_3–x O _y in air in a temperature range between 0 and 12 000°C were examined by means of thermographic and X-ray methods. Lithium and manganese form oxides with a spinel structure in a broad interval of the oxidation degree of manganese ions. As consequences of the oxidation degree and of the temperature, changes of the lattice parameters, of the cation distribution in the spinel lattice and the occurrence or disappearance of a tetragonal deformation of the lattice are experienced. In the temperature range between 950 and 1100°C probably the Li₂Mn₄O₇ compound and its solid solutions with Mn₃O₄ occur.The authors wish to express their gratitude to A. ápová, J. Mikulíková and E. Kitzinger for their helpful cooperation.     

Cation motion in α-silver iodide

Quasielastic neutron scattering results on α-AgI are presented along with a simple model for the cation motion which closely fits the data. This model is based on the superposition of a random local motion and translational jump-diffusion     

Reaktive Mikrogele. 5. Mitt. Über die Bildung von sulfatgruppenhaltigen Mikrogelen bei der Emulsionspolymerisation von Divinylbenzol

Ohne Zusammenfassung     

Surface orientation characterisation of rough mc‐silicon surfaces by confocal microscopy and EBSD

For many semiconductor and photovoltaic applications the quality of substrate surfaces is an important requirement for the development of new devices. Therefore, methods are needed to analyse the surface structure in detail. In the following a new method is described that allows a fast analysis of as‐cut or artificially modified and textured surfaces. It uses laser confocal microscopy images. Therefrom the orientation of small surface elements are detected and depicted in an orientation distribution function of surface normals. The method is applied to as‐sawn mc‐silicon surfaces. It will be shown that it is also possible to determine the grain orientation for grains near 〈111〉 crystal direction by this method. The combination of electron backscatter diffraction and orientation distribution function analysis enables the detailed investigation of surface elements of an anisotropic etched silicon wafer. Inhomogeneity of surface textures can easily and rapidly be visualised by this method. Copyright © 2012 John Wiley & Sons, Ltd.     

H2 separation using defect-free, inorganic composite membranes

Defect-free, microporous Al(2)O(3)/SAPO-34 zeolite composite membranes were prepared by coating hydrothermally grown zeolite membranes with microporous alumina using molecular layer deposition. These inorganic composite membranes are highly efficient for H(2) separation: their highest H(2)/N(2) mixture selectivity was 1040, in contrast with selectivities of 8 for SAPO-34 membranes. The composite membranes were selective for H(2) for temperatures up to at least 473 K and feed pressures up to at least 1.5 MPa; at 473 K and 1.5 MPa, the H(2)/N(2) separation selectivity was 750. The H(2)/CO(2) separation selectivity was lower than the H(2)/N(2) selectivity and decreased slightly with increasing pressure; the selectivity was 20 at 473 K and 1.5 MPa. The high H(2) selectivity resulted either because most of the pores in the Al(2)O(3) layer were slightly smaller than 0.36 nm (the kinetic diameter of N(2)) or because the Al(2)O(3) layer slightly narrowed the SAPO-34 pore entrance. These composite membranes may represent a new class of inorganic membranes for gas separation.     

Fission in238U+238U collisions below the Coulomb barrier

Integral fission cross sections in the system²³⁸U+²³⁸U were measured at beam energies below the interaction barrierV _C. Scattering angle dependent probabilities and integral cross sections for Coulomb fission were calculated. It is concluded that earlier observed discrepancies between measured and calculated angular distributions for the one-neutron transfer product²³⁹U cannot be explained by sequential fission. Multi-nucleon transfer induced fission is observed down to energies (0.90±0.02)×V_C.     

NO fundamental and first hot ro-vibrational line frequencies from MIPAS/Envisat atmospheric spectra

MIPAS (Michelson Interferometer for Passive Atmosphere Sounding) is a high spectral resolution interferometer (0.035 cm⁻¹ unapodized) covering a very wide spectral range (from 4.16 to 16.4 μm) with high sensitivity that was successfully launched on the 1st of March 2002 on the European Envisat satellite. MIPAS has measured spectra of the Earth’s upper atmosphere in the 4.3 μm region with the highest spectral resolution so far reached in this altitude region. This high spectral resolution permitted to obtain the frequency position of ro-vibrational NO⁺ transitions with an unprecedented accuracy. It has been found that the spectral line positions of the NO⁺ (1-0) ro-vibrational band are shifted by about ∼0.15 cm⁻¹ with respect to those listed in the HITRAN 2004 compilation. Also, spectral line positions of the NO⁺ (2-1) ro-vibrational band are shifted by approximately 0.05-0.1 cm⁻¹ with respect to those listed in the HITRAN 2004 compilation. A new set of Hamiltonian constants for NO⁺ has been derived from MIPAS data which is suggested to be used in future HITRAN compilations.