Showing papers by "University of Warsaw published in 1971"
TL;DR: In this paper, a sample of some 7500 K − meson captures at rest on hydrogen in emulsion giving rise to charged Σπ pairs was used to determine r, the decay branching ratio of the Σ + hyperon, λ, the ratio of Σ − to Σ+ hyperon production, τ Σ−, the lifetime of the ǫ − hyperon and C 10 −12 sec.
111 citations
TL;DR: In this paper, the absorption spectra of Ti (d2), V (d3), Cr (d4), Fe (d6), Co (d7), Ni (d8), and Cu (d9) in CdSe-Kristallen are presented.
Abstract: The absorption spectra of Ti (d2), V (d3), Cr (d4), Fe (d6), Co (d7), Ni (d8), and Cu (d9) in CdSe crystals are presented. The main features of the spectra are successfully interpreted using crystal-field theory for the states of 3dn configuration in a potential of predominantly Td symmetry. It is found that the oscillator strengths of the observed absorption bands are in the range 10−2to 10−5 due to transitions within the 3dn shell. The crystal-field parameters, Δ, and the Racah parameters, B and C, are determined where possible, and discussed.
Die Absorptionsspektren von Ti (d2), V (d3), Cr (d4), Fe (d6), Co (d7), Ni (d8) und Cu (d9) in CdSe-Kristallen werden mitgeteilt. Die Hauptcharakteristiken der Spektren lassen sich erfolgreich mittels Kristallfeldtheorie fur Zustande der 3dn-Konfiguration, auf die ein Potential mit uberwiegender Td-Symmetrie wirkt, interpretieren. Es wird gefunden, das die Oszillatorstarken der beobachteten Absorptionsbanden fur ubergange innerhalb der 3dn-Schale im Bereich von 10−2 bis 10−5 liegen. Die Kristallfeldparameter Δ und die Racah-Parameter B und C werden, soweit moglich, bestimmt und diskutiert.
56 citations
TL;DR: In this paper, the reduction and oxidation processes of uranium(VI, (V), (IV) and (III) in aqueous perchlorate solutions have been studied using the dropping mercury electrode, the hanging mercury drop electrode and the thin-layer technique.
50 citations
TL;DR: The experiments indicate that the gonads, together with adjacent tissues (mesonephros, mesentery) of a chick embryo are attractive to mouse primordial germ cells and that the hypothetical attractive substance is not species specific.
Abstract: Hind guts of 9½-day mouse embryos were transplanted into the posterior part of the coelomic cavity of 2½-day chick embryos. The hosts were sacrificed after 1-7 days and the mouse primordial germ cells (PGCs) in the graft and in the surrounding host tissues were searched for by means of the histochemical technique for alkaline phosphatase. Altogether 94 grafts were examined. During the first 3 days of intracoelomic development of the graft accumulations of mouse PGCs close to the mesonephros, the mesentery or the gonad of a chick embryo were observed in 26 out of 51 cases. In 12 grafts single PGCs crossed the boundary between the host and the graft and settled in host tissues such as the mesonephros, the mesentery or the gonad. After 3 days mouse PGCs are no longer visible in the chick tissues. However, the number of PGCs in the grafts also gradually decreases and from the 4th day onwards many of the grafts contain no PGCs. The ability of mouse PGCs to survive extragonadally, even in the embryonic hind gut, is thus limited. In some of the 4- to 7-day-old grafts PGCs occur on the periphery of the graft in the form of single aggregations. From the 6th day the only PGCs which survive are those in aggregations. The experiments indicate that the gonads, together with adjacent tissues (mesonephros, mesentery) of a chick embryo are attractive to mouse primordial germ cells and that the hypothetical attractive substance is not species specific.
42 citations
40 citations
TL;DR: In this article, a nonrelativistic quantum theory of a particle having both electric and magnetic charges moving in an arbitrary external electromagnetic field is presented, which is based on the hydrodynamic formulation of quantum mechanics.
Abstract: The nonrelativistic quantum theory of a particle having both electric and magnetic charges moving in an arbitrary external electromagnetic field is presented The theory is based on the hydrodynamic formulation of quantum mechanics Dirac's quantization condition for the electric and magnetic charges is rederived as a consistency condition for the motion of the probability fluid Neither the wave function nor the electromagnetic potential, which were the source of ambiguities in all other formulations, appears in our approach Nevertheless, this theory has all the essential features of the standard quantum mechanics, including the superposition principle
37 citations
TL;DR: In this article, the photoionization absorption spectra of Cr and Fe impurities in CdSe are presented, and the ionization energies and the matrix elements of electric dipole transitions are determined.
Abstract: The photoionization absorption spectra of Cr and Fe impurities in CdSe are presented. They are very well described in terms of photo-transitions from the localized 3d shell to the conduction band. The ionization energies and the matrix elements of electric dipole transitions are determined. It is found that deep donor levels of Cr2+ and Fe2+ arc 0.62 and 0.63 eV above the top of the valence band, respectively and are temperature-indepenent. Observed spectra of CdSe:Fe2+ are succesfully correlated with previously published results of photosensitive EPR of CdSe:Fe3+. The photoionization processes for other transition metal impurities are discussed. The ionization energies for some of them are estimated.
Photoionisierungs-Absorptionsspektren von Cr- und Fe-Defekten in CdSe werden mitgeteilt. Sie lassen sich durch Photoubergange von lokalisierten 3d-Zustanden zum Leitungs-band gut beschreiben. Die Ionisierungsenergien und Matrixelemente der elektrischen Dipol-ubergange werden bestimmt. Es wird gefunden, das tiefe Donatorzustande von Cr2+ and Fe2+ 0,62 bzw. 0,63 eV oberhalb des Maximums des Valenzbandes liegen und temperatur-unabhangig sind. Die beobachteten Spelrtren von CdSe: Fe2+ konnten erfolgreich mit den schon fruher veroffentlichten Ergebnissen der photoempfindlichen EPR an CdSe:Fe ver-knupft werden. Photoionisierungsprozesse fur andere Ubergangsmetalldefekte werden diskutiert und Ionisierungsenergien fur einige von ihnen berechnet.
26 citations
TL;DR: Analysis of the spectral data, particularly those for the infrared, establish the neutral form of inosine as the 6-keto.
26 citations
TL;DR: In this article, the half-wave potentials of p -substituted nitrobenzenes and benzaldehydes in dimethylformamide depend on the ionic potential φ of the cations of the electrolyte.
25 citations
TL;DR: The shape of photoionization spectrum connected with removal of an electron from the 3dn shell of a transition metal impurity into the conduction band has been calculated in this paper, where the influence of configurational mixing between 4pn and 3dn states on the shape of the spectrum is discussed.
Abstract: The shape of photoionization spectrum connected with removal of an electron from the 3dn shell of a transition metal impurity into the conduction band has been calculated. The influence of configurational mixing between 4pn and 3dn states on the shape of the spectrum is discussed. The absorption coefficient for uniaxial crystals (α for E ‖ c and E ⊥ c, c crystal axis) is given.
Die mit der Entfernung eines Elektrons aus der 3dn-Schale einer Ubergangsmetallver-unreinigung ins Leitungsband verbundene Form des Photoionisationsspektrums wird berechnet. Der Einflus von Konfigurationmischung von 4pn- und 3dn-Schalen auf die Form des Spektrums wird diskutiert. Der Absorptionskoeffizient fur einachsige Kristalle (α fur E ‖ c und E ⊥ c, c Kristallachse) wird angegeben.
25 citations
TL;DR: In this article, the relationship between the time dependence of quantum operators and the corresponding dynamical variables in the underlying classical theory is discussed. But the authors focus on the quantum system in the Heisenberg picture.
TL;DR: The results as a whole indicate that the perceptual set for aggressive stimuli and the presence of such stimuli have an interactive effect on aggressive tendencies.
Abstract: A word association test which included aggressive stimuli (weapon names) was given to college students. Those whose responses were relatively high or low in emotionality were asked to participate in a “study of stress reactions to electric shock” When the subject arrived at the laboratory, he and a partner were given tasks to perform The partner, a confederate of the experimenter, gave the subject an unfairly high number of shocks in judging the subject's performance The subject then judged the partner's work, using shock Half the subjects were in the apparently accidental presence of guns when given the chance to retaliate Among low-emotionality subjects, the presence of guns increased the number of shocks given the partner, as Berkowitz and LePage found High-emotionality subjects tended to give the partner longer shocks than low subjects, whether guns were present or not. In contrast to the low subjects, when guns were present, highs tended to give shocks of shorter duration and to report lowered anger, as if the aggressive stimuli had dampened the intensity of their reaction. The results as a whole indicate that the perceptual set for aggressive stimuli and the presence of such stimuli have an interactive effect on aggressive tendencies
TL;DR: In this article, a geometrical approach to the twistor formalism is described, and a description of the compactification M of the Minkowski space M compatible with its conformal structure is given.
TL;DR: The plhotoaddition intermediates represent a new class of dihydropyrimidines, namely analogs of 5, 6-dihydro-5,6-cyclobutanyluracil and its nucleosides; the biological significance is discussed.
Abstract: Irradiation at 254 nm of aqueous solutions of 5-ethyl-, 5-propyl-, and 5-isopropyluracils (or their nulcleosides) leads to cleavage of the 5-alkyl substituents, via an intramolecular electrocyclic photoaddition intermediate, with formation of uracil (or its nucleoside). The plhotoaddition intermediates represent a new class of dihydropyrimidines, namely analogs of 5,6-dihydro-5,6-cyclobutanyluracil and its nucleosides; the biological significance is discussed.
TL;DR: In this article, the authors used the Mossbauer effect for studying the absorption of 14.4 keV gamma rays from 57 Co by samples consisting of filters through which atmospheric air was pumped.
Abstract: Use of the Mossbauer effect has been made for studying iron in atmospheric air. The experiments were performed by observing the absorption of 14.4 keV gamma rays from 57 Co by samples consisting of filters through which atmospheric air was pumped. Using the “area method”, usually applied in calculations of the recoilless raction ( f -factor) the content of natural iron per cubic meter of atmospheric air was found to be 1.4 ? g /m 3 . The measurements were carried out at room and liquid nitrogen temperatures. The room temperature spectra show two absorption lines due to quadrupole splitting; the low temperature spectrum shows a central unresolved doublet and, besides it, six lines due to magnetic hyperfine splitting. From the shapes of the Mossbauer spectra obtained it was inferred that iron appears in the Fe 2 O 3 compound in the form of ultrafine particles (? 100 A) in the superparamagnetic state. DOI: 10.1111/j.2153-3490.1971.tb00560.x
TL;DR: The observations presented here are discussed in view of the previous findings concerning diurnal changes in RNA and protein synthesis as well as the appearance of neurosecretory material in the cells.
TL;DR: In this article, the authors measured the pressure and temperature dependences of the Hall mobilities of the alloys of the Cd-Hg alloys and showed that the variation of the dielectric constant with carrier concentration is asymmetric about the energy gap.
Abstract: The pressure and temperature dependences of the Hall mobilities ${\ensuremath{\mu}}_{H}$ of ${\mathrm{Cd}}_{x}{\mathrm{Hg}}_{1\ensuremath{-}x}\mathrm{Te}$ alloys, with $x=0.07, 0.095, 0.13, \mathrm{and} 0.18$ have been measured from 4.2 to 77 \ifmmode^\circ\else\textdegree\fi{}K at pressures up to 8.40 katm. The ${\ensuremath{\mu}}_{H}$ appear to be determined primarily by lattice scattering at the highest temperatures and by ionized impurity scattering at 4.2 \ifmmode^\circ\else\textdegree\fi{}K. A minimum in ${\ensuremath{\mu}}_{H}$ vs $T$ at approximately 10 \ifmmode^\circ\else\textdegree\fi{}K is observed for the $x=0.13 \mathrm{and} 0.18$ samples. There is little variation with pressure of the temperature associated with the minimum. The variation of ${\ensuremath{\mu}}_{H}$ with energy gap ${E}_{G}$ as determined by pressure measurements on the $x=0.07 \mathrm{and} 0.13$ samples is asymmetric about ${E}_{G}=0$, in accordance with a recent theory of ionized impurity scattering in these systems which takes the variation of the dielectric constant with carrier concentration into account.
TL;DR: In this paper, the energies and envelope functions of acceptor levels in tellurium were calculated by the variational procedure within the effective mass approximation, and good accordance with experimentally determined levels is obtained.
TL;DR: In this paper, the authors used the field data of Samsonowicz and the sorting equation after Frost to estimate the mass and number of fragments from the Pultusk meteorite shower 1868.
Abstract: The earlier efforts to approximate the total number and mass of fragments from Pultusk meteorite shower 1868 have been found unsatisfactory
With the use of the field data of Samsonowicz and the sorting equation after Frost, differential expressions approximating the mass and number of fragments are derived. These expressions numerically integrated over the elliptical strewnfield area lead to the estimates ∼ 1.8 times 105 and ∼ 2 times 106 g for the total number and mass of fragments respectively.
The meaning of the obtained results is discussed.
TL;DR: In this paper, the Riccati equation is reduced to two especially simple forms, one of them being the Riemann equation, and examples of solutions are given for a perfect fluid sphere in general relativity.
TL;DR: In this article, the distributions in the Feynman variable x for the pions produced in the inclusive reactions (1) π+p → π− + anything and (2) δp → δ+pπ+ + anything) are compared at 8 and 16 GeV/c.
TL;DR: In this paper, it was shown that the Haag algebra assigned to a set coincides with the one assigned to the whole Minkowski space for a certain class of sets, called total ones.
TL;DR: In this article, a relativistic quantum mechanics of dyons (hypothetical particles endowed with both electric and magnetic charges) is formulated, and the hydrodynamic formulation of quantum mechanics is used to overcome all problems created by the simultaneous presence of both electric or magnetic charges.
Abstract: A relativistic quantum mechanics of dyons (hypothetical particles endowed with both electric and magnetic charges) is formulated. The hydrodynamic formulation of quantum mechanics is used to overcome all problems created by the simultaneous presence of both electric and magnetic charges. In the case of one dyon moving in the electromagnetic field of another dyon the exact solutions are found and the energy levels are determined.
TL;DR: In this paper, it is shown that such quantum notions as the superposition of states, projection operators, etc., possess certain counterparts in classical mechanics, such as the degeneracy of dynamical systems, higher symmetries, etc.
TL;DR: In this article, the binding energy of a Λ-particle in a potential well representing a heavy hypernucleus is considered and the exact solution of the Schrodinger equation with a potential of a Fermi (Saxon-Woods) shape is obtained.
TL;DR: Circadian variations in intensity of RNA synthesis were found, which were particularly distinctive in the neurosecretory cells of the ganglion and the follicular epithelial cells of oocytes and of the fat body.
TL;DR: In this paper, the effects of electrolyte concentration and solvent composition on the changes in surface potential of LiCl solutions in water-methanol systems were investigated and the χCH3OH value was estimated as ca −0.25 V.
TL;DR: A reaction scheme consistent with the foregoing, and other, data is the photohydration of the 5,6 bond of the excited singlet state of the chlorouracil monoanion, followed by the very rapid dark climination of Cl− to give barbituric acid.
TL;DR: In this article, the rate of increase of the intensity of several free and bound excition lines as a function of excitation intensity has been determined, and the line with the highest rate was interpreted as being due to interaction of two free excitons.
TL;DR: In this paper, an investigation of the influence of high pressures on the electron mobility in CdxHg1−xTe was made, and the established energy band structure for this material is in full agreement with the experimental results obtained.
Abstract: An investigation is made of the influence of high pressures on the electron mobility in CdxHg1−xTe. It is shown, that the established energy band structure for this material is in full agreement with the experimental results obtained. Scattering on ionized impurities and on optical phonons was considered in the calculation of μ = f(x) at 77 K. The calculation of μ = f(x) is qualitatively consistent with the measured data.
Es wurde der Einflus von hohem Druck auf die Elektronenbeweglichkeitin CdxHg1−xTe untersucht. Es wird gezeigt, das die aufgcstellte Energiebandstruktur voll mit den erhaltenen experimentellen Ergebnissen ubereinstimmt. Bei der Berechnung von μ = f(x) bei 77 K wurde Streuung an ionisierten Storstellen und optischen Phononen berucksichtigt. Die Bereehnung von μ = f(x) ist qualitativ konsistent mit den gemessenen Werten.