XPS investigation of LPE garnet films

XPS spectra of YIG, YIG:Bi, YIG:Ca and YIG:Co(Ge, Ca) epitaxial garnet films were measured at room temperature. The positions of the main iron, yttrium, oxygen, bismuth, cobalt and lead spectral lines were determined and their changes with the surface treatments were investigated. It was found that divalent and trivalent states of iron and cobalt ions can be resolved, the chemical shifts being in oposite directions.The authors would like to thank Dr. J. <img src="/content/u8283mn08782pj37/xxlarge353.gif" alt="scaron" align="BASELINE" BORDER="0">im<img src="/content/u8283mn08782pj37/xxlarge353.gif" alt="scaron" align="BASELINE" BORDER="0">ová for careful EPMA analysis of the samples.     

Electronic structure of amorphous Nb1-x Si x films studied by X-ray emission and X-ray photoelectron spectroscopy

We present valence band spectra of the amorphous system Nb_1–x Si _x (0.2<img src="/content/n72w2032305295x2/xxlarge8804.gif" alt="le" align="MIDDLE" BORDER="0">x<img src="/content/n72w2032305295x2/xxlarge8804.gif" alt="le" align="MIDDLE" BORDER="0">0.8), of bcc-Nb and of a-Si obtained by X-ray photoelectron spectroscopy (XPS, Al K_{<img src="/content/n72w2032305295x2/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">}) and X-ray emission spectroscopy (XES, Si K-emission bands). The samples were prepared as thin films by sputtering. The origin of all prominent spectral features was identified and consistently correlated to Si 3s-, Si 3p-and Nb 4d-derived states. The Nb4d-Si3p coupling is stable in binding energy over a wide concentration range. There is strong experimental evidence that the short range order changes considerably within the concentration interval 0.4<img src="/content/n72w2032305295x2/xxlarge8804.gif" alt="le" align="MIDDLE" BORDER="0">x<img src="/content/n72w2032305295x2/xxlarge8804.gif" alt="le" align="MIDDLE" BORDER="0">0.7, whereas the partial density of states of the Si 3p-electrons is clearly altered in the small concentration range 0.50<img src="/content/n72w2032305295x2/xxlarge8804.gif" alt="le" align="MIDDLE" BORDER="0">x<img src="/content/n72w2032305295x2/xxlarge8804.gif" alt="le" align="MIDDLE" BORDER="0">0.57.     

Localization and symmetry of valence states in GaS

The valence electron states of layered semiconductor GaS were studied by polarizedK X-ray emission bands. The polarized gallium and sulphurK bands were calculated and GaK<img src="/content/x77370g60xx44661/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">₂-bands were measured by the two crystal spectrometer. In the calculations the self-consistent pseudo-potential method was applied. Thep _x ,p _y p _z -character and localisation of valence electron states were identified. Comparison with the results of controversial interpretation of photoemission and tight binding calculations were done and analysed in detail.We are indebted to J. Mikkelsen from Xerox Research Center in Palo Alto for kindly sending us the GaS single crystals.     

Energy independent number of clusters and multiplicity distribution at Collider and beyond

Multiplicity distributions up to the Collider energies could be described by various two-parameter compounded distributions having in common Poisson distributed number of clusters. Among them the logarithmic distribution for hadronization via decaying clusters leads to energyindependent number of clusters above the ISR energies, replacing the previous KNO-scaling.Dedicated to the 30th anniversary of the Joint Institute for Nuclear Research.     

Investigations for Modification of Polyacrylamide-Bentonite by Phytic Acid and its Usability in Fe3+, Zn2+ and UO2 2+ Adsorption

Composite of polyacrylamide-bentonite (PAA-B) was prepared by direct polymerisation of PAA in a suspension of bentonite (B). Adsorption and thermodynamic features of phytic acid (Phy) adsorption onto B, PAA and PAA-B, and those of Fe³⁺, Zn²⁺, UO₂ ²⁺ adsorption onto PAA-B and its modification by Phy (PAA-B-Phy) have been investigated. The reusability, storagability, ion selectivity and recoverability of sorbed ions with 1 M HCl have also been considered.The chemical and physical structure of adsorbents has been characterised by means of FT-IR and XRD. All adsorption isotherms for Phy and the ions were L-type of the Giles classification except, the one which is S type for adsorption of Phy onto PAA. The maximum adsorption capacities for the ions adsorbed were in order of UO₂ ²⁺ > Fe³⁺ > Zn²⁺ for PAA-B and Zn²⁺ > Fe³⁺ > UO₂ ²⁺ for PAA-B-Phy. Langmuir equilibrium constants for the adsorption of ions onto PAA-B-Phy were significantly higher than those found for PAA-B; the magnitude of increase for UO₂ ²⁺ was about 100. The thermodynamic parameters indicated that adsorption reactions are spontaneous in terms of adsorption free enthalpy.The chemical structure of PAA-B-Phy was not changed at the end of the studies of reusability and storagability. The composite was selective for UO₂ ²⁺ of the ions of interest.The composite of PAA-B and its modification by Phy have been used for the first time in this investigation. It is proposed that the composites can be practically used in the investigations and applications of adsorption.     

Über Reaktionen von Nitrosophenolen, 3. Mitt.: Reaktion von 2-Nitroso-1-naphthol mit Resorcin und Orcin

Zusammenfassung Die Reaktion von 2-Nitroso-1-naphthol mit Resorcin bzw. Orcin in Äther bei Anwesenheit von HNO₃ liefert Benzo[c]phenoxazon-(9) (I), Benzo[c]phenoxazon-(9)-12-oxid (II), Methyl-benzo[c]phenoxazon-(9) (III) sowie 11-Methyl-benzo[c]phenoxazon-(9)-12-oxid (IV). Die Struktur der isolierten Substanzen wurde durch Reduktion mittels TiCl₃ sowie durch die UV- und IR-Spektren gestützt.

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The reaction of 2-nitroso-1-naphthol with resorcinol and orcinol in ether solution in the presence of nitric acid has been studied. From the reaction mixture the benzophenoxazones I–IV have been isolated. Structures were assigned on the grounds of UV and IR spectra and partly by using TiCl₃ as a reducing agent.

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Mit 1 Abbildung     

Capillary isotachophoresis of some isoquinoline alkaloids

The isotachophoretic behavior of quaternary benzo/c/phenanthridine, protoberberine and aporphine alkaloids in different electrolyte systems is described. The concentration of the leading ion and the pH value of the leading electrolyte affect the relative effective mobilities of the alkaloids. The system of pH 4.7, containing the leading ion K⁺ (0.005 M) counter ion acetate, and the terminating ion β-alanine (0.02 M), has been selected for the quantitative determination of the studied alkaloids in model mixtures and plant extracts.     

Magnetic moments and the high field susceptibilities of MnFe2O4

An extended version of the noncollinear spin model bySawatzky et al. is developed to derive a dependence of the differential high field susceptibility<img src="/content/g1122u5620015286/xxlarge967.gif" alt="chi" align="MIDDLE" BORDER="0"> on the degree of inversion of the ferrite MnFe₂O₄. Using the available data on the main molecular field coefficients it is shown that the present model imposes restrictions on values of<img src="/content/g1122u5620015286/xxlarge967.gif" alt="chi" align="MIDDLE" BORDER="0">. Determination of<img src="/content/g1122u5620015286/xxlarge967.gif" alt="chi" align="MIDDLE" BORDER="0"> from the measurements of the field dependence of the saturated moments at low temperatures on samples with varying degrees of inversion reveals good quantitative agreement with the present model.     

The bestL 2-approximation by finite sums of functions with separable variables

Summary We consider the problem of the best approximation of a given functionh <img src="/content/p3g1004578532551/xxlarge8712.gif" alt="isin" align="MIDDLE" BORDER="0"> L ² (X &times; Y) by sums<img src="/content/p3g1004578532551/xxlarge8721.gif" alt="sum" align="MIDDLE" BORDER="0"> _k=1 ⁿ f _k f _k, with a prescribed numbern of products of arbitrary functionsf _k <img src="/content/p3g1004578532551/xxlarge8712.gif" alt="isin" align="MIDDLE" BORDER="0">L ² (X) andg _k <img src="/content/p3g1004578532551/xxlarge8712.gif" alt="isin" align="MIDDLE" BORDER="0">L ² (Y). As a co-product we develop a new proof of the Hilbert—Schmidt decomposition theorem for functions lying inL ² (X &times; Y).     

Antitumoral and MMP-2 inhibition activity of raloxifene or tamoxifen loaded nanoparticles containing dimethyl-β-cyclodextrin

A new nanoparticle formulation has been developed by using dimethyl-β-cyclodextrin (DM-β-CD) with raloxifene HCl or tamoxifene citrate. Both drugs are insoluble in water and represent as low bioavailibilities when given orally. Tamoxifen has an FDA approval for breast cancer prevention and the treatment. Raloxifene is approved for osteoprosis treatment. Both drugs were selected as a model drug antitumoural activity and MMP-2 inhibition studies were evaluated on breast cancer cell lines MCF-7 and MDA-MB 231. MMP-2 is known to be responsible for tumour invasion and initation the of angiogenesis. DM-β-CD and sodium taurocholate (NaTC) have been used as absorption enhancers to increase penetration effect of raloxifene/tamoxifen on the tumour cells and aimed to provide high antitumoral activity and MMP-2 inhibition results by developed nanoparticle formulations. The effects of two absorption enhancers were compared. The highest antitumoral activity was observed for DM-β-CD—raloxifene HCl nanoparticle formulation and also MMP-2 enzyme inhibit effectively.