The pair distributions and the osmotic coefficient in binary electrolytes up to concentrations c 1 mol/l

Referring to the results of a previous paper dealing with the pair distributions in a fully ionized dilute hydrogen plasma it is concluded that the pair distributions in binary electrolytes up to concentrations c 1 mo1/1 take the form

Full-size image

. Here (r) represents the screened Coulomb potential and V(^hs)(r) a hard sphere potential. The contact distances R of the hard sphere potentials are assumed to be equal for ions with the same sign of their charges, that means R₊₊ = R_-- = R, and to be smaller than R for ions of opposite charges, that means R_+- = qR, 0 < q < 1. With the help of these pair distributions the pressure of the ionic components and the osmotic coefficient are calculated. The numerical evaluation of the osmotic coefficient of hydrous electrolytes at T = 273 K shows that the above pair distributions explain the experimental data of all kinds of 1-1-valent electrolytes, even those of the tetra-alkylammonium halogenids, within a domain of very reasonable values of R and q. No necessity seems to exist for considering additional short range attractive forces. Furthermore, some numerical results for 2-2-valent electrolytes in water are given. It comes out that the osmotic coefficient of all 2-2-valent electrolytes with R 5 Å is larger than the limiting law in a certain domain of concentration.     

The electric conductivity of stationary and homogeneous electrolytes up to concentrations c ≈ 1 mol/l and high electric fields

Following a previous paper the electric conductivity of stationary and homogeneous electrolytes at high electric fields is investigated. It turns out that the increase of the molar conductivity at high electric fields which is observed experimentally can be explained only if an additional boundary condition in the differential equation for the pair distribution is taken into account. As a consequence also the electric conductivity at low electric fields is modified. The numerical results for hydrous electrolytes are in a good agreement with experimental data.     

Angular distributions of channeled pions and protons up to 250 GeV/c

Channeling phenomena are observed for positive particles of momentum up to 250 GeV/c in a germanium crystal. The polar angular distributions of the channeled particles are compared with theoretical predictions based on a diffusion model. The results indicate that at high particle energy there may be additional mechanisms besides those operative at low energy leading to dechanneling of the particles. In spite of this, channeling effects are observed for particles incident at up to several times the critical angle, in contrast with the results from low energy channeling. Statistical equilibrium in the azimuthal angular distribution has also been observed at all measured beam momenta to about twice the calculated channeling critical angle. The breakdown of statistical equilibrium for the 2 cm crystal used occurs at an incident angle 2–3 times smaller than predicted theoretically.     

The mean spherical model for asymmetric electrolytes: thermodynamics and the pair correlation function

It is shown that the RISM theory of molecular liquids provides an accurate prediction of the measured neutron scattering structure factor of deuterated liquid chloroform.     

Multiplicity distributions up to √s = 540 GeV in the dual parton model

We compute the average charge multiplicities and dispersions in proton-proton and antiproton-proton interactions up to SPS collider energies in the framework of a multi-chain dual parton model. The corresponding data for deep inelastic lepton-proton and e⁺e^? reactions are used as the sole input. The height of the central plateau is also computed.     

High pressure study on the superconducting transition temperature and Hall coefficient of Ba1−xKxBiO3 up to 8 GPa

The superconducting transition temperature (T_c) of Ba_0.62K_0.38Bio₃ (T_c=30 K) has been measured under high pressure up to 8 GPa. It is observed that T_c increases initially with pressure, as reported by Uwe et al., Shirber et al. and Huang et al., but decreases above 4 GPa. The Hall coefficient of Ba_0.62K_0.38BiO₃ has been measured up to 1.2 GPa. The absolute value of the Hall coefficient decreases with pressure by 10% GPa, the value of which is almost the same as that obtained in most CuO-based high-temperature superconductors.     

Interplay between carrier and impurity concentrations in annealed Ga1-xMnxAs: intrinsic anomalous hall effect

Investigating the scaling behavior of annealed Ga1-xMnxAs anomalous Hall coefficients, we note a universal crossover regime where the scaling behavior changes from quadratic to linear. Furthermore, measured anomalous Hall conductivities in the quadratic regime when properly scaled by carrier concentration remain constant, spanning nearly a decade in conductivity as well as over 100 K in T_[C] and comparing favorably to theoretically predicated values for the intrinsic origins of the anomalous Hall effect. Both qualitative and quantitative agreements strongly point to the validity of new equations of motion including the Berry phase contributions as well as the tunability of the anomalous Hall effect.     

Probing HZγ and Hγγ anomalous couplings in the process e~+e~-→ Hγ

We propose to measure the HZγ and Hγγ anomalous couplings in the process e+e-→Hγ with the sequential decay of H→bˉb. The discovery potential of observing the anomalous couplings are explored in detail.Our study shows that future electron–positron colliders have great potential to test the HZγ and Hγγ couplings.Conservative bounds on the two anomalous couplings are also derived when no new physics signal is detected on top of the SM backgrounds.     

Radiative corrections to muon pair and quark pair production in electron-positron collisions in the Z0 region

A calculation of first-order radiative corrections to the process e⁺e^?→μ⁺μ^? is presented, which is in particular applicable to the Z₀ region. The emphasis is on a detailed treatment of hard photon effects, which affect the size of the corrections in the Z₀ region considerably. The technique used is that of a Monte Carlo simulation of μ⁺μ^? and μ⁺μ^?γ events. In an appendix the generalization to quark pair production is presented.     

The anomalous behaviour of Gd atoms (Fe1−xMnx)2 compounds

The educed Gd atoms in the X-structure (Th₆Mn₂₃-type) of Gd(Fe_1−xMn_x)₂ were magnetically investigated by comparing with Gd₆(Fe_1−yMn_y)₂₃ whose structure is Th₆Mn₂₃-type. The magnetic properties of Gd(Fe_1−xMn_x)₂ (0.4≤x≤0.7) were observed to be quite similar to those of Gd₆(Fe_1−yMn_y)₂₃ (0.4≤y≤0.7).     

Absence of pair production in the CPn−1 model

We prove that the CP^n?1 model does not accomodate pair formation up to third order perturbation theory.     

Electrochemical, SEM/EDS and quantum chemical study of phthalocyanines as corrosion inhibitors for mild steel in 1 mol/l HCl

The inhibition effect of metal-free phthalocyanine (H₂Pc), copper phthalocyanine (CuPc) and copper phthalocyanine tetrasulfuric tetrasodium salt (CuPc·S₄·Na₄) on mild steel in 1 mol/l HCl in the concentration range of 1.0 × 10⁻⁵ to 1.0 × 10⁻³ mol/l was investigated by electrochemical test, scanning electron microscope with energy dispersive spectrometer (SEM/EDS) and quantum chemical method. The potentiodynamic polarization curves of mild steel in hydrochloric acid containing these compounds showed both cathodic and anodic processes of steel corrosion were suppressed, and the Nyquist plots of impedance expressed mainly as a capacitive loop with different compounds and concentrations. For all these phthalocyanines, the inhibition efficiency increased with the increase in inhibitor concentration, while the inhibition efficiencies for these three phthalocyanines with the same concentration decreased in the order of CuPc·S₄·Na₄ > CuPc > H₂Pc according to the electrochemical measurement results. The SEM/EDS analysis indicated that there are more lightly corroded and oxidative steel surface for the specimens after immersion in acid solution containing 1.0 × 10⁻³ mol/l phthalocyanines than that in blank. The quantum chemical calculation results showed that the inhibition efficiency of these phthalocyanines increased with decrease in molecule's LUMO energy, which was different from the micro-cyclic compounds.     

Preparation of LixCa1−xTiO3 solid electrolytes by the sol-gel method

Solid electrolytes based on lithium doped CaTiO_3,Li_xCa_1−xTiO₃ (x=0-0.5) were prepared by the sol-gel method in an ethanol and water mixture medium. Phase identification and morphology observation of the products were carried out by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that the Li_xCa_1−xTiO₃ powders sintered above 700 ^°C are of cubic perovskite structure and the mean size of Li_xCa_1−xTiO₃ powders is about 80 nm. A study of ionic conductivity by AC impedance implies that the conductivity of Li_xCa_1−xTiO₃ increases with the increase of substituted Li⁺ ions and reaches a maximum value of 4.53×10⁻⁴ S cm⁻¹ at x=0.1, and then decreases for x>0.1.     

The c‐map,Tits Satake subalgebras and the search for inflaton potentials

In this paper we address the general problem of including inflationary models exhibiting Starobinsky‐like potentials into (symmetric) supergravities. This is done by gauging suitable abelian isometries of the hypermultiplet sector and then truncating the resulting theory to a single scalar field. By using the characteristic properties of the global symmetry groups of the supergravities we are able to make a general statement on the possible α‐attractor models which can obtained upon truncation. We find that in symmetric models group theoretical constraints restrict the allowed values of the parameter α to be . This confirms and generalizes results recently obtained in the literature. Our analysis heavily relies on the mathematical structure of symmetric supergravities, in particular on the so called c‐map connection between Quaternionic Kähler manifolds starting from Special Kähler ones. A general statement on the possible consistent truncations of the gauged models, leading to Starobinsky‐like potentials, requires the essential help of Tits Satake universality classes. The paper is mathematically self‐contained and aims at presenting the involved mathematical structures to a public not only of physicists but also of mathematicians. To this end the main mathematical structures and the general gauging procedure of supergravities is reviewed in some detail.     

An anomalous absorption spectrum: The missing zero-phonon line of the F2-centre in KC1 crystals

The absorption spectrum of the M₁ band due to F₂-centres in KC1 has been measured at 2°K. No zero-phonon line could be detected, though a very strong line is predicted.     

Apparent anomalous behavior of the power spectrum of 1/f noise and its explanation

The explanation is given for the apparent anomalous behavior of the power spectrum of 1/f noise as if it corresponded to the total infinite power of noise sources. Physical mechanisms eliminating the apparent anomalies are described. With these mechanisms, the finite and integrable 1/f-noise power spectra fitting the known physical concepts of noise processes are obtained in the low-and high-frequency limits.     

An association theory for the formation of ion oligomers and its application to 1-1 electrolytes

A theory for modelling electrolyte solutions which includes the formation of ion clusters of different size has been developed in the framework of the primitive model. In primitive models the solvent is described as a dielectric continuum and the solvent–solute interactions are neglected. For the dielectric constant the value of the pure solvent has been used. The ion cluster distribution is calculated from the mass action law. The association constants are related to integrals over the cluster distribution functions which are calculated with the Kirkwood superposition approximation from low density pair distribution functions. The ion clusters are defined by a certain distance which rules if two ions belong to the same cluster. This so-called Bjerrum distance is chosen according to fundamental investigations of the structure of ion cluster. All ion clusters are modelled as hard spheres. For the free ions and charged clusters the mean spherical approximation expression for the Coulomb interaction is added. The co-volumes of the ion clusters have been taken from the investigation of the ion cluster structures, and are consistent with the definition of an ion cluster chosen here.     

Charge distributions of the isobar pair 40Ar-40Ca from a phenomenological and a model-independent analysis of elastic electron scattering

Cross sections for elastic electron scattering from ⁴⁰Ar have been measured for the momentum transfer range from 0.8 to 1.8 fm^?. The data were analysed by various phenomenological models as well as by a model-independent method. Using the results of Stanford measurements on ⁴⁰Ca analysed in a similar manner, the difference of the charge distributions of ⁴⁰Ar and of ⁴⁰Ca has been calculated. The combined results of the phenomenological analysis are compared with the results of the model-independent analysis.