Showing papers by "Jagiellonian University published in 1975"

The effect of light on the esr spectra of humic acids

Abstract: Summary Photo-induced Electron Spin Resonance signals have been detected in basic aqueous solutions of humic acids from soil and from synthetic and commercial sources. Parameters of these signals under atmospheres of air, O2 and N2 were the same as or very similar to those of the already known ‘dark’ stable ESR-signals of humic acids and melanins. The maximum increase of signal amplitude under the influence of 395–780 nm wavelength irradiation was one order of magnitude. The influence of microwave power on ESR-signal amplitude was examined under different atmospheres. It has been found that oxygen strongly diminishes the saturability of signals. This indicates that oxygen has an influence upon relaxation properties of paramagnetic centres of humic acid. Photoinduced ESR signal is a newly discovered feature of humic acids, similar to that of melanin and may be expected to affect physico-chemical processes occurring in soils.

Viscous universes without initial singularity

Abstract: It is shown that within a certain class of cosmological models (homogeneity and isotropy, two-component non-interacting fluid, density-dependent coefficient of bulk viscosity) the introduction of bulk viscosity effectively removes the initial singularity.

Consumption and utilization of natural foods by the common hamster

Abstract: Zbadano stosunki pokarmowe chomikow Cricetus cricetus (Linnaeus, 1758) metodą analizy zolądkow. Na podstawie morfologii epiderm oznaczono zielone cześci 11 gatunkow roślin, a na podstawie ziaren skrobi oznaczono nasiona 6 roślin uprawnych. Do badan nad skladem pokarmowym uzyto 100 zolądkow, z ktorych 75 zawieralo pokarm z lata, a pozostale 25 zawieralo pokarm z jesieni.

Transferred hyperfine fields at the tin site in the heusler-type alloys Co2YSn (Y = Ti, Zr, Hf, V)

Abstract: The hyperfine magnetic fields at the tin site in ferromagnetic Heusler type alloys Co2YSn (Y = Ti, Zr, Hf, V) were measured by the Mossbauer effect using 23.9 keV γ-line in 119mSn. The samples were checked by X-ray diffraction analysis, magnetization measurements, and neutron diffraction method (for Co2TiSn only). The results were interpreted in terms of the Blandin-Campbell formalism and qualitative agreement with the experimental data was obtained for a number of conduction electrons per atom of about 0.5. Mit dem Mosbauereffekt wurden die magnetischen Hyperfeinfelder an den Zinnplatzen der ferromagnetischen Heusler-Legierungen Co2YSn (Y = Ti, Zr, Hf, V) mittels der 23,9 keV γ-Linie von 119mSn gemessen. Die Proben wurden durch Rontgenstrahlenanalyse, Magnetisierungsmessungen und Neutronenbeugungsmethoden (nur fur Co2TiSn) untersucht. Die Ergebnisse werden mit dem Blandin-Campbell-Formalismus interpretiert, wobei qualitative Ubereinstimmung mit den experimentellen Werten fur eine Anzahl von Leitungselektronen von etwa 0,5 pro Atom erhalten wird.

Photoinduced luminescence and epr signals of polyphenol and quinone polymers

Abstract: — Aqueous basic solutions, pH 9.0 of humic acids and melanin-like, synthetic polymers, obtained with adrenochrome, hydroquinone and purpurogallin, were illuminated with visible light under N2 or O2 atmospheres. It has been found that light enhances a singlet electron-paramagnetic-resonance (EPR) signal of polymers both under N2 and O2, and induces ultra-weak luminescence in the presence of O2. Degradative oxidation of polymers, accelerated by light, leads to a decrease of EPR signal intensity and generates weak chemiluminescence.

Effects of induced pinocytotic activity and extreme temperatures on the morphology of Golgi bodies in Amoeba proteus.

Abstract: The morphology of the Golgi apparatus of Amoeba proteus can be influenced by substances inducing pinocytotic activity as well as by extreme temperatures. During the ingestion of a solution of 0.5% egg white the number of Golgi bodies decreases from 100% measured in control cells to 82% measured in cells showing induced pinocytosis. Simultaneously the ratio of the surface area of the cisternae at the proximal face to that of the vesicles at the distal face of single dictyosomes remains constant (1.74–1.72). The decrease and increase of the temperature of the culture medium to 4° C and 30° C respectively, causes the disappearance of most of the dictyosomes. After keeping the cells for 3–10 h at these temperatures the number of Golgi bodies was only 5–10% of the controls. A continued treatment with cold or warm culture medium leads to a partial reorganization of dictyosomes. After 15 h the number of Golgi bodies counted per cell returned to 57% at 4° C and 38% at 30° C. The ratio of the surface area of the Golgi cisternae to the surface area of the Golgi vesicles also alters under the influence of extreme temperatures. The values measured after treating the cells for 3 h, 4 h 10 h and 15 h at 4° C and 30° C amounted to 0.75, 0.85, 1.14 1.53 and 0.93, 0.38, 0.88, 1.60, respectively, compared to 1.72 of control amoebae. The different values of the ratio of the surface area of cisternae to that of vesicles indicate that there are strong morphological changes of single dictyosomes.

Temperature Dependence of E1 and E1 + Δ1 Maxima in the Fundamental Reflection for Cdx Hg1‐xTe Solid Solutions

Abstract: The width of the energy gap at the A-point of the Brillouin zone was measured in the temperature range from 100 to 315 K for CdxHg1-xTe solid solutions. Measurements were carried out for Cd content from 0 to 17%. The thermal coefficients of the El and El + Δl transitions were determined for the above mentioned range of composition. Some anomalies in the E1(T) dependence have been found for volume compositions x = 0.125. A possible connection between these anomalies and the inversion of band structure is discussed. Es wurde die Breite der Energielucke am A-Punkt der Brillouinzone von CdxHg1-x Te- Mischkristallen im Temperaturbereich von 100 bis 315 K bestimmt. Die Messungen wurden fur einen Cd-Gehalt von 0 bis 17% durchgefuhrt. Des weiteren wurden fur den oben angegebenen Zusammensetzungsbereich die thermischen Koeffizienten der E1- und E1 + Δ1- Ubergange bestimmt. Einige Anomalien in der E1(T)-Abhangigkeit wurde fur die Zusam- mensetzung x =0,125 gefunden. Ein moglicher Zusammenhang zwischen diesen Ano- malien und der Inversion der Bandstruktur wird diskutiert.

Raman spectroscopy study of powdered [Ni(NH3)6] X2 compounds

Abstract: Ten out of eleven Raman active modes were detected in [Ni(NH3)6] X2 powders, apart from internal modes of the X− ions. The Raman active lattice mode happens to agree fairly well with the predictions of a model based on the electrostatic potential field of point charges. The X = Cl compound showed evidence of losing ammonia during irradiation with the laser beam. Two modes (the NNiN angle deformation and the lattice vibration) are especially sensitive to the NH3− vacancies thus created.

Calorimetric and infra-red study of the phase situation in solid mbba

Abstract: — If MBBA is solidified by decreasing the temperature of the nematic phase, one obtains a metastable solid, whose specific heat vs. temperature curve has been measured by adiabatic calorimetry. This curve shows a sharp rise at melting. It also shows a quasi-second-order type of behaviour at about 210 K. If the metastable form of solid MBBA is kept for a few hours at a temperature not far below melting, it spontaneously transforms into the stable form, whose specific heat vs. temperature curve has also been measured. This curve lies below that of the metastable form and has a monotonic behaviour and a sharp rise at melting, which now occurs at a slightly higher temperature. Infra-red and far-infrared spectra of the two modifications of solid MBBA were also measured. In the internal vibration wave number region the spectra are significantly different in the whole temperature range. The quasi-second-order phase transition discovered in the metastable MBBA by calorimetry does not show up in IR. Differences between the spectra of the two modifications are greatest in the lattice vibration region, i. e. between 20 cm and 100 cm-. Preliminary powder X-ray diffraction data, obtained for the two modifications, show patterns typical of crystalline materials. The X-ray pattern changes significantly when the metastable MBBA transforms into the stable modification.

Effect of electric field on mixing of Frenkel excitons and charge transfer states of a linear molecular crystal

Abstract: The mixing between Frenkel excitons and charge-transfer states of a linear molecular crystal in an electric field is investigated. The Merrifield model is adopted. It is shown that the electric field increases the above mentioned mixing, leading therefore to an increase of the light absorption with simultaneous creation of an electron–hole pair. It also can change slightly the position of the Frenkel exciton absorption line. Semiempirical calculations of anthracene dimers in an electric field show that this effect should be observable at electric fields with strengths higher than 106 V/cm, the direction of the field being along the long c-axis of the anthracene crystal. Es wird die Mischung zwischen einem Frenkel-Exziton und Chargetransferzustanden in einem linearen Molekulkristall im elektrischen Feld untersucht, wobei das Modell von Merrifield angenommen wird. Es wird gezeigt, das das elektrische Feld die Mischung erhoht und zu einer Erhohung der Lichtabsorption fuhrt bei gleichzeitiger Bildung eines Elektron-Lochpaares. Es kann auch die Lage der Absorptionslinie des Frenkel-Exzitons leicht andern. Halbempirische Berechnungen von Anthrazendimeren im elektrischen Feld zeigen, das dieser Effekt bei elektrischen Feldstarken von groser als 106 V/cm beobachtbar sein sollte, bei einer Richtung des elektrischen Feldes in Richtung der langeren c-Achse des Anthrazenkristalls.

Notes on the European Species of Procloeon Bengtsson with Particular Reference to Procloeon bifidum (Bengtsson) and Procloeon ornatum Tshernova (Ephemerida: Baetidae)

Abstract: A comparative description of imagines, subimagines, eggs, and nymphs of Procloeon bifidum (Bengtsson) and P. ornatum Tshernova is given on the basis of material from Poland. Some remarks about the type specimens of both species are presented with the designation of their lectotypes. From the other European species of Procloeon Bngtss. the P. pseudorufulum Kimmins and P. lychnidense lkonornov are regarded as the junior synonyms of P. bifidum (Bengtsson).

On Jaśkowski-type semantics for the intuitionistic propositional logic

Abstract: One of remarkable results of Jaskowski is the construction of a se? quence of finite matrices adequate for the intuitionistic propositional logic (INT). This result was published in 1936 in the paper [2] where only a very condensed sketch of proof is to be found. It was 17 years before a more detailed proof was published in [4] by Bose who worked out some modification of the strategy suggested by Jaskowski for eluding the lemma which the was unable to prove. A detailed proof following closely the Jaskowski's strategy is presented in [7]. The sequence of finite matrices adequate for INT was obtained by Jaskowski as a result of alternate application of the operation of direct power and s.c. V ? operation to the two-element Boolean algebra. This T ? operation of Jaskowski can be considered as a special case of the sum operation for pseudo-Boolean algebras introduced later by Troelstra [8]. Suppose we are given the pseudo-Boolean algebras 31 and 93 with the universes A, B such that {!<%} = {Ojb} = Ar\B. Then the sum 3??23 is the pseudo-Boolean algebra with the universe AuB and the lattice-ordering <5I@S = <^u

Morphological and X‐ray study of SiC crystals grown from gas phase

Abstract: SiC crystals obtained from the gas phase were investigated in order to characterize their morphology and polytypic modifications. Specific X-ray patterns showed the occurrence of one-dimensional disorder in some of α-SiC crystals. [Russian Text Ignored].