Die Bestimmung des Harzes in Seifen und Fetten

Ohne Zusammenfassung     

Spectroscopic investigation of cyclodextrin monomers,derivatives, polymers and azo dyes (1)

Circular dichroism (CD) and visible spectra of inclusion compounds between Methyl Orange (MO) analogues and -, -, -cyclodextrin (cdx), 2,6-dimethyl-and 2,3,6-trimethyl--cdx, water soluble -, -, -cdx polymer products were investigated. In the CD-spectroscopic investigation, the complex with -cdx epichlorohydrin condensate showed a large amplitude and splitting of the induced ^* band. Fractions of glyceryl ether of less than 2000 and polymer of more than 10000 dalton molecular mass were separated. Complexes of above two fractions and MO showed the same splitting spectral pattern. Job's plots from visible spectra showed the formation of the 11 complex and CD-data suggested the co-existence of the 21 MO-cdx complex. This splitting pattern showed the reversal of the signs when -cdx-ethyleneglycol-bis(epoxypropyl) ether was used and disappeared when larger host molecules and azo dyes were used. The splitting was explained by exciton interaction.     

4He+ ion beam irradiation induced modification of poly(dimethylsiloxane). Characterization by infrared spectroscopy and ion beam analytical techniques

In this study we investigated the chemical and surface wettability changes of poly(dimethylsiloxane) (PDMS) induced by a 2.0 MeV He(+) beam irradiation. The chemical changes created in PDMS were characterized by universal attenuated total reflectance infrared (UATR-FTIR) spectroscopy, while the changes of the wettability were determined by contact angle measurements. In a separate analysis, hydrogen depletion was also investigated with a 1.6 MeV He(+) beam by applying the elastic recoil detection analysis (ERDA) and Rutherford backscattering spectrometry techniques simultaneously. The ERDA results showed that the hydrogen content of PDMS decreased irreversibly, which means that volatile products were formed under radiolysis, such as hydrogen or methane. The results were completed with UATR-FTIR measurements. We propose a complete reaction mechanism for the processes taking place in PDMS. These ion beam induced processes, such as chain scissions, cross-linking, and depletion of small molecular weight fragments, lead to the formation of a silica-like final product (SiO(x)). The significant chemical changes at the surface influence the wettability of PDMS, making it considerably more hydrophilic. The penetration depth of the 2.0 MeV He(+) ions is significantly higher compared to that of other surface modification techniques, which makes the modified layer thick and homogeneous; on the other hand, it is easily controllable by the energy of the incident ions.     

Automorphisms of Ehresmann connections

We prove that a diffeomorphism of a manifold with an Ehresmann connection is an automorphism of the Ehresmann connection, if and only if, it is a totally geodesic map (i.e., sends the geodesies, considered as parametrized curves, to geodesies) and preserves the strong torsion of the Ehresmann connection. This result generalizes and to some extent strengthens the classical theorem on the automorphisms of a D-manifold (manifold with covariant derivative). The second author is supported by the Hungarian Nat. Sci. Found. (OTKA), Grant No. NK68040.     

A generalization of Weyl's theorem on projectively related affine connections

From a physical point of view, the geodesics in a four-dimensional Lorentzian spacetime are really significant only as point sets. In 1921 Weyl proved that two torsion-free covariant derivative operators D_M and on a manifold M have the same geodesics with possibly different parametrizations if and only if there is a 1-form α on M such that , where 1 is the identity (1,1) tensor on M. By a theorem of Ambrose, Palais and Singer [1], torsion-free covariant derivative operators are generated by affine sprays, and vice versa. More generally, any (not necessarily affine) spray induces a number of covariant derivatives in the tangent bundle τ of M, or in the pull-back bundle τ∗τ. We show that in the context of sprays, similarly to Weyl's relation, a correspondence between the Yano derivatives can be detected.     

On the Finsler-metrizabilities of spray manifolds

In this essentially selfcontained paper first we establish an intrinsic version and present a coordinate-free deduction of the so-called Rapcsák equations, which provide, in the form of second order PDE-s, necessary and sufficient conditions for a Finsler structure to be projectively related to a spray. From another viewpoint, the Rapcsák equations are the conditions for the Finsler-metrizability of a spray in a broad sense. Second, we give a reformulation in terms of 0-homogeneous Hilbert 1-forms of both this and another metrizability problem, called Finsler-metrizability in a natural sense. (The latter is just a Finslerian version of the classical inverse problem of the calculus of variations.) Finally, in our main theorem we provide a reduction of the Rapcsák equations to a first order PDE with an algebraic condition. The preparatory parts of the paper are devoted to a careful elaboration of the necessary technical tools, while in an Appendix the computational background is summarized.     

The enthalpy of formation of 2II CH

The standard enthalpy of formation, δ_fH^o, of² II CH has been determined at converged levels of ab initio electronic structure theory, including high order coupled cluster and full configuration interaction benchmarks. The atomic Gaussian basis sets employed include the (aug)-cc-p(C)VXZ family with X = 3, 4, 5 and 6. Extrapolations to the complete one-particle basis set and the full configuration interaction limits, where appropriate, have been performed to reduce remaining computational errors. Additional improvements in the enthalpy of formation of ²II CH were achieved by appending the valence-only treatment with core-valence correlation, relativistic effects including spin-orbit correlation, and the diagonal Born-Oppenheimer correction. The recommended values for δfH^o ₀ and δA_f H _o ²⁹⁸ of ²II CH are 592.48^+0.47 _?0.56 kJ mol_?1 and 595.93 ^+0.47 _?0.56 kJ mol_?1, respectively.     

Fabrication of optical devices in poly(dimethylsiloxane) by proton microbeam

Optical diffraction grating and micro Fresnel zone plate type structures were fabricated in relatively thin poly(dimethylsiloxane) (PDMS) layers using proton beam writing technique and the performance of these optical devices was tested. PDMS is a commonly used silicon-based organic polymer, optically clear, generally considered to be inert, non-toxic and biocompatible. PDMS has been used as a resist material for direct-write techniques only in very few cases. In this work, PDMS was used as a resist material; the structures were irradiated directly into the polymer. We were looking for a biocompatible, micropatternable polymer in which the chemical structure changes significantly due to proton beam exposure making the polymer capable of proton beam writing. We demonstrated that the change in the structure of the polymer is so significant that there is no need to perform any development processes. The proton irradiation causes refractive index change in the polymer, so diffraction gratings and other optical devices like Fresnel zone plates can be fabricated in this way. The observed high order diffraction patterns prove the high quality of the created optical devices.     

Investigation of Thermal Degradation of PVC in the Solid State

The thermal degradation of PVC powders and the inhibition of this process by cadmium laurate was investigated by the measurement of discoloration, diffuse reflectance spectra, and the quantity of hydrochloric acid formed. Kinetic analysis of the data obtained by us previously showed that both the data of color measurements and those of diffuse reflectance spectra may be used conveniently for the calculation of the number of double bonds formed during the degradation.