[en] The authors study the anisotropic Ising model on a square lattice with free boundary conditions. A simple explicit result is obtained for the surface magnetization of a system which is inhomogeneous near the surface. The corner magnetization is investigated for a 90 degrees corner in a homogeneous anisotropic system. From the numerical results an analytical formula is found

[en] Recently published epidemiological reports indicate lung cancer mortality amongst foundry workers at DOFASCO, Ltd., was higher than found elsewhere in the plant or control populations. Presented are preliminary work on mutagen screening efforts and studies on the use of various sampling devices and on optimization of the assays, followed by data which show a diverse range of mutagenic compounds present in foundry air particulates

[en] We are studying flux qubits based on Nb/Al/Al₂O₃/Nb tunnel junctions. The qubit consists of three Josephson tunnel junctions connected in series in a superconducting loop and is read out by an inductively coupled SQUID. In order to obtain a nondestructive readout, the SQUID is part of an LC circuit, whose resonant frequency depends on the inductance of the SQUID and hence on the qubit state. We have carried out numerical simulations in order to obtain values for the minimum energy level splitting Δ and the persistent current I_p. Suitable design parameters were found and the influence of possible parameter deviations due to fabrication tolerances was studied. Furthermore, we investigated methods to reduce the stray inductance of the readout LC circuit and hence increase the readout resolution. (orig.)

[en] The role of the substituent on the phenyl ring of the β-adrenergic drugs in the interaction with the receptor was investigated. The abilities of 50 compounds to compete for the [³H] dihydroalprenolol binding sites and to stimulate adenylate cyclase were determined in frog erythrocyte membranes, which possess characteristics of B-2 adrenergic receptors. The structure-activity relationship was studied by comparing their oxidation peak potential [)Ep) vs. Ag/AgCl] with their binding affinities (K/sub d/) and intrinsic activities (IA, maximum ability to stimulate adenylate cyclase). The structures of β-agonists and antagonists tested were closely related. There were derivatives of ethanolamine or of oxypropanolamine. Both the IA and Ep were determined primarily by the nature of the substituents on the phenyl ring. The ethanolamine side chain was redox inactive and was essentially associable with their binding affinities to the receptors. All the antagonists tested (28) exhibited Ep greater than or equal to 0.75, suggesting that they were difficult to oxidize. Agonsits, however, exhibited a wide range of Ep (0.3-0.7V). Drugs that had low Ep (0.25-0.4V) showed high IA (greater than or equal to 0.8, isoproterenol as 1). Therefore, it is proposed that the oxidizing tendency of the meta-substitutent on the phenyl ring is one of the factors that influences the IA

[en] Published in summary form only

[en] Indium monoiodide is proposed as a suitable alternative to hazardous mercury, i.e. the emitting component inside the compact fluorescent lamps (CFL), with comparable luminous efficacy. Indium monoiodide-argon low pressure lamps are electrodelessly driven with surface waves, which are launched and coupled into the lamp by the ‘surfatron’, a microwave coupler optimized for an efficient operation at a frequency of 2.45 GHz. A non intrusive diagnostic method based on spatially resolved optical emission spectroscopy is employed to characterize the plasma parameters. The line emission coefficients of the plasma are derived by means of Abel’s inversion from the measured spectral radiance data. The characteristic plasma parameters, e.g. electron temperature and density are determined by comparing the experimentally obtained line emission coefficients with simulated ones from a collisional-radiative model. Additionally, a method to determine the absolute plasma efficiency via irradiance measurements without any goniometric setup is presented. In this way, the relationship between the plasma efficiency and the plasma parameters can be investigated systematically for different operating configurations, e.g. electrical input power, buffer gas pressure and cold spot temperature. The performance of indium monoiodide-argon plasma is compared with that of conventional CFLs. (paper)

[en] One important aspect of climate changes for the long-term safety assessment of radioactive waste repositories is its impact on exposure pathways for humans in the future, which are dependent on the environmental characteristics mentioned. It is conceivable that effects or processes occurring during climate changes lead to an increased accumulation and/or release of radionuclides in the biosphere resulting in higher doses compared to that calculated for discrete climate states. In order to shed light on this question key processes are identified which might lead to such an increased accumulation and/or release of radionuclides. The transition from one climate to another can cause changes in the physicochemical composition of radionuclides: some of them may become more available for plant uptake and due to this, their activity concentration in the plants increases. Other radionuclides maybe stronger bound to soil and their activity concentration in plants decreases. Such changes might also cause remobilization of radionuclides from localised areas with contaminated sediments, their re-suspension and transfer to the surrounding areas. A suitable illustration of the processes related to the changes of the redox potential is the examination of a dry lake or fen bed for agricultural purposes as pasture or ameliorated pasture. In these cases the accumulation of radionuclides in the lake or fen sediment is followed by their release and increasing mobility after agricultural processing of the dry bed of lake or fen. Ploughing of the soil leads to increased supply of oxygen to previous anoxic soil layers causing an increase in redox potential. The presented model describes a scenario, where the land is initially very humid and very low Eh-values cause high sorption and accumulation of radionuclides in soil particles. Then this land is dried out, the redox potential increases and redox sensitive radionuclides change their speciation and their behaviour. Such processes might lead to an increased contamination of plants grown on this land. For redox sensitive radionuclides three processes play a crucial role in the contamination of pasture grass in these scenarios: the increase of transfer of radionuclides from soil to grass caused by a change of the radionuclide redox state, the initial contamination of soil due to rising ground water and the additional contamination of soil due to irrigation. The estimation shows that during the transition from one climate to another, the contamination of plants with such nuclides as Tc-99 and Se-79 can increase by a factor of 1000. The potential exposures to populations in this case increase correspondingly. Document available in abstract form only. (authors)

[en] A new collisional-radiative model for a mercury-free low pressure plasma based on an indium(I) iodide-argon system is presented. The electron impact cross sections and rate coefficients for ionization, excitation and dissociation, as well as de-excitation, three-body recombination and dissociative recombination, of studied fillings have been calculated. Additionally, the coefficients for free and ambipolar diffusion were determined. The rate balance equations for individual generation and loss processes have been created. Densities of ions, electrons and neutral particles (ground or metastable state) are presented as a function of electron temperature for varied lamp parameters, such as argon buffer gas pressure and cold spot temperature (coldest point of discharge vessel). With the help of the presented model, the line emission coefficients of essential emission lines of indium for given electron temperatures and densities can be predicted. (paper)

[en] Time-resolved MOKE (TRMOKE) and Q-band ferromagnetic resonance (FMR) are used to evaluate the damping parameter α and the magnetic anisotropy field (where K is the uniaxial anisotropy constant and is the saturation magnetization) of CoPtX–Y and CoPtX (where X is non-magnetic element and Y denotes oxide(s)) granular alloys with perpendicular magnetic anisotropy and variable Co/Pt atomic ratio R. It is found that α monotonically increases in the range of 0.03–0.07 with decreasing R in the range of 2.5–5.5. By comparing the CoPtX films sputter-deposited in Ar and in Ar+O₂ atmosphere, it is found that α is less sensitive than H _K to the presence of non-magnetic additives (Cr, B) in the grain core. This suggests that α is much less sensitive than K to perturbations of d-electron band structure. FMR and TRMOKE are also used to evaluate α of magnetically soft CoFeX alloys. It is shown that adding 2 at.% Tb to CoFeX leads to an increase of α from 0.012 (undoped case) to 0.048, and a negative shift of the resonance field which is linearly dependent on the RF frequency. This effect, similar to that previously reported on Tb-doped NiFe films, is attributed to the highly anisotropic Tb 4f–5d exchange coupling. A synthetic-antiferromagnetic trilayer CoFeX (7 nm)/Ru (0.8 nm)/CoFeX (7 nm) is investigated by FMR. The interlayer RKKY coupling constant, evaluated from the frequency shift between the acoustic (symmetric) and optic (antisymmetric) resonance modes is J _EX  =  0.11 erg cm⁻². The α value corresponding to the acoustic mode (0.016) matches that of a single-layer CoFeX film whereas the optic mode shows a higher α (0.0265). This is interpreted to be a consequence of spin-pumping through the Ru interlayer. The evaluated spin mixing conductance for the CoFeX/Ru interface is   =  22.5 nm⁻². (paper)

[en] Theoretical and experimental fully differential cross sections are presented for electron-impact ionization of molecular hydrogen in a plane perpendicular to the incident beam direction. The experimental data exhibit a maximum for 1-eV electrons detected 180 deg. apart and a minimum for 10-eV electrons. We investigate the different physical effects which cause back-to-back scattering and demonstrate that, over the energy range from 10 to 1 eV, a direct transition is observed from a region where Wannier threshold physics is essentially unimportant to where it completely dominates.