Cosmological models in the scalar-tetradic theory B

We present two methods for solving the cosmological equations of the scalar-tetradic theory B [19] when a Friedmann-Robertson-Walker (FRW) geometry is assumed. Among the many solutions found there are several physically meaningful ones including inflationary universe solutions.     

On the origin of additional peaks in the photoelectron spectra of yttrium

Ultraviolet Photoemission analysis of yttrium metal reveals well defined features far below the conduction band. In order to elucidate their origin, we have used X-ray/Ultra violet photoelectron spectroscopy together with inverse photoemission. The comparison of the spectra of clean yttrium and of H exposed yttrium suggests that these structures are most probably due to hydrogen bands, hydrogen being either in a stable surface hydride form or as subsurface H.     

Etude thermoanalytique de substances psychotherapeutiques. II. Substances antipsychotiques. Chlorprothixene,chlorhydrate de chlorpromazine,chlorhydrate de levomepromazine,dichlorhydrate de fluphenazine

The thermoanalytical study of chlorprothixene (a), chlorpromazine hydrochloride (b), levomepromazine hydrochloride (c), and fluphenazine hydrochloride (d), has enabled the existence of polymorphs for (b) and (d) to be shown. The thermal stability and decomposition kinetics of commercial forms of the drugs have been determined. The thermal behaviour of (c) and (d) does not permit their study by transparency method nor the determination of their degree of purity by differential scanning calorimetry. The temperatures and intervals of fusion are given for (a) and (b). Knowing the thermal behaviour, the degree of purity: 99.47 ± 0.11% (a), 99.61 ± 0.20% (b); enthalpy: 27.82 ± 1.05 (a), 28.42 ± 0.57 (b) kJ mole^?1; and entropy of fusion have been evaluated by differential scanning calorimetry.     

Détermination de la pureté de la sulfapyridine s par analyse thermométrique

Résumé L'étude thermoanalytique de la pureté de deux échantillons de sulfapyridine, médicament (I) et standard (II), a été réalisée par différentes méthodes. Par mesure de la transparence les valeurs moyennes de la température et du domaine de fusion indiquent une teneur en impureté plus faible pour (II) que pour (I). Disposant de deux analyseurs thermiques de conception différente, les auteurs ont montré l'excellente concordance des résultats: 99.790 ± 0.047 % et 99.800 ± 0.045 % (I). Seule l'analyse calorimétrique différentielle permet d'évaluer avec précision le taux de pureté de (II) 99.956 ± 0.028 %, valeur représentant un seuil pour l'analyse calorimétrique différentielle à compensation de puissance (DSC 1B).

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The thermoanalytical purities of two sulfapyridine samples, drug (I) and standard (II), have been studied with different methods. By transparency measurement the fusion temperatures and intervals indicate a lower percentage of impurity for (II) than for (I). By means of two thermal analyzers the authors have shown the good agreement of the results: 99.790±0.047% and 99.800±0.045% (I). Heat-flux differential scanning calorimetry is the only method able to give precisely the degree of purity of (II): 99.956±0.028 %, this value being a limit for the power-compensation differential scanning calorimetry analysis (DSC 1B).

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Zusammenfassung Das Studium der thermoanalytischen Reinheit der beiden Sulfapyridinproben drag(I) und standard(II) wurde durch verschiedene Methoden durchgeführt. Schmelztemperaturen sowie-bereiche zeigen im Falle von Transparenzmessungen einen geringeren Prozentsatz von Verunreinigungen für (II) als für (I). Unter Anwendung zweier Thermoanalyser zeigten die Autoren die gute Übereinstimmung der Ergebnisse: 99.790±0.047% und 99.800 ± 0.045 % für (I). Ein Wärmeströmungs-Differentialabtastkalorimeter bietet die einzige Möglichkeit den Reinheitsgrad von (II) genau zu bestimmen: 99.956 ± 0.028 %, wobei dieser Wert die Grenze für die Kraft-Kompensations-Differentialkalorimetrie (DSC 1B) darstellt.

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: (I) (II). , , II , I. , : 99.790±0.047% 99.800 ± 0.045% I. II: 99.956 ± 0.028% ( 1).

     

Transient dark photovoltaic spatial solitons and induced guiding in slab LiNbO(3) waveguides

Dark photorefractive photovoltaic spatial solitons are demonstrated at 532 nm in nominally undoped and slightly Fe-doped LiNbO(3) planar optical waveguides. The spatial solitons are observed in a transient regime before transverse modulation instability occurs. Their widths are intensity independent as predicted by theory. Meanwhile, excited mode distribution and Fe-doping concentration are shown to influence soliton width. The guiding properties of soliton-induced waveguides are also presented.     

Etude thermoanalytique et spectrale de l'interaction lorazepam/PEG 6000

Résumé The solubility and rate of dissolution of a poorly-soluble active principle are of importance when substances are destined for oral administration. Physical blends in wich drug and carrier are able to form particular compositions, such as a eutectic, may exibit an increased rate of dissolution. In this work the interactions lorazepam and PEG 6000, were examined, the particular thermal behaviour of lorazepam being taken into account. An eutectic was obtained and its composition was studied by means of differential scanning calorimetry, thermomicroscopy, infrared spectroscopy and X-ray methods.

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Zusammenfassung Bei der oralen Darreichung von Substanzen ist die L?slichkeit und Aufl?sungsgeschwindigkeit schlechtl?slicher aktiver Komponenten von gro?er Bedeutung. Physikalische Gemische, in denen Wirkstoffe und Tr?gersubstanzen besondere Zusammensetzungen wie zum Beispiel Eutektika zu bilden in der Lage sind, k?nnen eine erh?hte Aufl?sungsgeschwindigkeit zeigen. Vorliegend wird die Wechselwirkung zwischen Lorazepam und PEG 6000 untersucht, wobei das besondere thermische Verhalten von Lorazepam berücksichtigt wurde. Es wurde ein Eutektikum erhalten und dessen Zusammensetzung mittels DSC, Thermomikroskopie, Infrarotspektroskopie und R?ntgenmethoden untersucht.