Bemerkung zu der Arbeit von Fr iederich H?lscher, Argentometrisehe Halbmikro-Bestimmung von Chlor und Brom in organischen Substanzen

Ohne Zusammenfassung     

Manifestation of phase transformations in optical spectra of Na0.5Bi0.5TiO3 crystals between 25°C and 350°C

The pseudo dielectric function ?ε? (E) = ?ε ₁? (E) + i?ε ₂? (E) of sodium bismuth titanate Na_0.5Bi_0.5TiO₃, has been obtained in the spectral range of electronic excitations (2–9.5 eV) by spectroscopic ellipsometry using the synchrotron radiation source BESSY II. The spectrum contains a broad absorption band at 4.2–4.5 eV. The temperature dependence in the range of 25–350°C is presented by the related susceptibilities ?χ ₁? (T) and ?χ ₂? (T) at 5 eV. A clear peculiarity in the temperature behavior of ?χ ₁? (T) and ?χ ₂? (T) between 180 and 320°C has been revealed and discussed. In this range an extremum-like temperature dependence of intensity of the light reflected from the sample surface, has been revealed and can be explained by the diffraction of light on the grid of the elastic domain structure of the sample.     

Alkylated poly(styrene-divinylbenzene) monolithic columns for mu-HPLC and CEC separation of phenolic acids

Macroporous poly(styrene-divinylbenzene) monolithic columns were prepared in fused silica capillaries of 100 microm id by in-situ copolymerization of styrene with divinylbenzene in the presence of propan-1-ol and formamide as the porogen system. The monoliths were subsequently alkylated with linear alkyl C-18 groups via Friedel-Crafts reaction to improve the retention and chromatographic resolution of strongly polar phenolic acids. A new thermally initiated grafting procedure was developed in order to shorten the time of the alkylation process. The grafting procedure was optimized with respect to the reaction temperature, time, the grafting reactant concentration, and the solvent used. The type of solvent and the grafting temperature are the most significant factors affecting the hydrodynamic properties, porosity, and efficiency of the columns. While the equivalent particle diameter of the grafted column increased, the capillary-like flow-through pore diameter decreased in comparison to non-alkylated monoliths. The hydrodynamic permeability of the monolith decreased, but the monolithic column still permitted fast micro-HPLC separations.     

Studies on Effect of Tri(2-hydroxypropyl), Tri(2-hydroxybutyl) and Tri(hydroxythiodiethylene) Borates on Thermal and Heat Properties of Rigid Polyurethane-Polyisocyanurate Foams

Effect of tri（2-hydroxypropyl）, tri（2-hydroxybutyl）and tri（hydroxythiodiethylene） borates （BT2HB, BT2HP and BTHET） on the thermal and heat properties of the rigid polyurethane-polyisocyanurate （PUR-PIR） foams was investigated： Increasing amounts of BT2HB and BT2HP in the foam composition, from 0.05 to 0.4 of chemical equivalent, caused increases in the softening point, the temperature of the first mass loss, the extrapolated tempera- ture of the main mass loss foam and temperature of the highest rate of the mass loss. In the case when BTHTE was added to the foam compositions, the lower increase in the mentioned above characteristic temperatures was observed as compared to those of standard foam （without borate added）.     

Dual surface coil with high-B1 homogeneity for deep organ MR imaging

The theory and construction of a dual surface coil which provides good B₁ homogeneity and sensitivity in a defined volume of interest is described. The probe comprises two coaxial rings, of different diameters and in different planes, which carry opposing currents of different values. Current in the second ring compensates for the roll-off of the B₁ field associated with a single surface coil. Coupling between the rings and a third matching ring is by mutual inductance only. A comparison to a traditional surface coil with practical application to pig brain imaging at a field strength of 7 Tesla is shown.     

Interpolation and inner maps that preserve measure

It is shown, for n ? m ? 1, that there exist inner maps Φ: Bⁿ → B^m with boundary values $\text{Φ}{}_1\text{: B}{}^{\mathrm{n}}\text{→ B}{}^{\mathrm{m}}$ such that $\text{σ}{}_{\mathrm{m}}\text{(A) = σ}{}_{\mathrm{n}}\text{(Φ}{}_1{}^{\mathrm{?1}}\text{(A))}$. where σ_n and σ_m are the Haar measures on ?Bⁿ and ?B^m, respectively, and A ? Bⁿ is an arbitrary Borel set.     

The Gibbs measures and partial differential equations

We investigate the connections of the Gibbs measures, which appear in Euclidean Field Theory, and the corresponding partial differential equations of Classical Euclidean Field Theory.