Resonance line transfer and transport of excited atoms—III. Self-consistent solutions (2)

In this last part of our study on non-LTE line transfer with convective transport of excited atoms, we present self-consistent solutions of the radiative transfer equation and the kinetic equation of the excited two-level atoms when the excited atoms undergo elastic velocity-changing collisions. We assume pure Doppler broadening of the spectral line and investigate reflecting and destroying boundaries for the excited atoms. Concerning elastic collisions of the excited atoms, our study covers all cases, from a collisionless gas (free particle streaming) discussed in Part II of this series of papers to a collision- dominated gas with the limiting case of complete redistribution. We present arguments that the streaming pattern of the gas of excited atoms does not depend critically on the shape of the line profile. Therefore, our results for a pure Doppler profile may also be used for other line profiles (Voigt, Lorentz) in first approximation, at least when the streaming parameter η is not too large.     

ΛN and ΣN Interactions from Lattice QCD

We present our recent study on ΛN and ΣN (isospin I = 3/2) interactions by measuring Nambu–Bethe–Salpeter wave functions on the Lattice QCD. The lattice QCD calculation is performed by using the N _f  = 2 + 1 gauge configurations generated by PACS-CS collaboration together with employing an improved method to obtain potentials in lattice QCD simulations. For the ¹ S ₀ channel, the central ΣN (I = 3/2) potential and the central ΛN (¹ S ₀) potential are found to be very similar. For the spin triplet (³ S ₁?³ D ₁) channels, the central ΛN(³ S ₁?³ D ₁) potential is attractive while the central ΣN(I = 3/2, ³ S ₁?³ D ₁) potentials is repulsive. Tensor potentials, on the other hand, are rather weak in both ΛN and ΣN(I = 3/2) systems.     

Doping of solid solutions in liquid epitaxy. III. Tellurium in AlxGa1−xSb

A calculation is made of the dependences of the coefficient of the tellurium distribution K_Te and the electron concentration n in Al_xGa_1–xSb on the composition of the solid solution and the growth temperature. It is shown that K_Te must decrease with increasing x. The dependence of K_Te on the temperature is also determined by x. Experimental results were obtained on Al_xGa_1–x Sb (0 x 0.74) films grown by liquid epitaxy. The electron concentration in the films was measured through the thermoelectric power and the capacitance-voltage characteristics of Schottky barriers. Satisfactory agreement with the results of the calculation was obtained.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 19–25, April, 1980.We thank G. K. Arbuzov for assistance in preparing the surface-barrier structures.     

BEEM-π calculations for a series of pyridines and their 14N N.Q.R.

The ⁵⁷Fe Mössbauer spectrum of a powdered sample of phthalocyanine-iron(II) in an applied magnetic field of 3·0 teslas has been measured as a function of temperature in the range 4·2 K to 100 K. Measurements have also been made at 4·2 K with 6·0 teslas applied, and on a single crystal specimen at 4·2 K with 3·0 teslas applied. Independent computer fits to the three measurements taken at 4·2 K were found to be consistent with one another, and showed that detailed information concerning magnetic anisotropy can be obtained even from powdered samples of paramagnets by Mössbauer spectroscopy. Although the asymmetry parameter in the electric field gradient tensor was found to be small, there was a significant departure from tetragonal symmetry in the magnetic properties of the molecule. The magnetic hyperfine field at the ⁵⁷Fe nucleus was found to be positive in all directions, indicating that all three electronic g values are significantly greater than 2·0.     

Synthesis and Characterization of a Biologically Active Lanthanum(III)–Catechin Complex and DNA Binding Spectroscopic Studies

A lanthanum(III) complex of catechin has been synthesized and characterized by elemental analysis, molar conductance, UV-Vis spectra, infrared spectra, thermal analysis, and ¹H NMR. The complex behaves as a nonelectrolyte in methanol solvent. The spectral and thermal properties of the complex are examined. A thermogravimetric (TGA) study showed the hydrated nature of the complex. ¹H NMR spectra of the lanthanum and the catechin (CT) ligands measured in CD₃OD-d₄ also show metal ligand coordination. The lanthanum–catechin complex shows bright luminescence in methanol solution. The interaction of the complex with calf thymus DNA has been investigated by absorption and emission spectroscopic measurements. Experimental spectral results suggest CT–DNA binding with catechin complex via an intercalative mode.     

Lepton-flavor-violating pion decay π+→μ−νμ e + e + and SU(3)C ⊗ SU(3)L ⊗ U(1)N model

Within the minimal SU(3)_C ? SU(3)_L ? U(1)_N model, the lepton-flavor-violating decay π⁺→μ^?ν_μ e ⁺ e ⁺ is calculated without directly invoking lepton mixing. The branching ratio for this rare pion-decay mode is found to be much smaller than the current experimental upper limit. If the anomalous interactions are discarded, this result coincides with the result of the previous calculation.     

Mössbauer and N.M.R. studies of ErFe2Hx

Hydrides of Intermetallic compounds have been the object of many studies because of their potential applications/1/. Recent papers were devoted to the problem of interstitial site occupation in connection with H-H exclusion rule (d_H–H > 2.1 A). The present work deals with ErFe₂H_X, which has been investigated both by⁵⁷Fe Mössbauer Effect and by¹⁶⁷Er N.M.R. Previous studies were limited to X 2, 3.5, 4.1. Here five values of x (1.45, 1.6, 1.84, 2.6, 3.3) are considered, in order to obtain information on hydrogen location, filling and diffusion as a function of x, and also on hydrogen contribution to the electric field gradient (E.F.G.) and crystalline field at the Rare Earth.     

Comments on “Rigorous bounds on the radiative interaction between real gases and scattering particles” by D. G. Goodwin and J. L. Ebert

Claims are made by Goodwin and Ebert that the work by Skocypec and Buckius¹ is “erroneous.” This claim is shown to be inappropriate and incorrect. The analytical technique, exact results and charted solutions as presented in Ref. [1] are correct and the claims by Goodwin and Ebert² are not legitimate. The form of the presentation of the charted solutions in Ref. [1]is misleading and results are presented in this paper to interpret these charted solutions more fairly. These results predict the interaction of gaseous emission with scattering and the bounds are in qualitative agreement with that obtained by standard spectral analysis. The spectral analysis presented in Ref. [2]has been available in the literature for some time. To be able to predict radiative heat transfer in a real gas and scattering medium (not only predict the maximum interaction), detailed real gas and scattering analyses as presented in Ref. [1] are required since total real gas effects are accurately modeled.     

Morphological features of composites prepared from polylactide and iron(III)−tetraphenylporphyrin complex

A material based on polylactide and iron(III)–tetraphenylporphyrin complex is prepared. The UV electronic spectra of the samples indicate the presence of porphyrin microinclusions in the polylactide matrix. According to optical microscopy, these inclusions have a size of 50–200 μm. It is determined that the melting point of the polylactide matrix decreases by 1–3°C with increasing porphyrin content in the composition. An experiment at a temperature of 40 ± 1°C shows that the degree of crystallinity of the polylactide matrix of the compositions varies insignificantly and does not exceed the degree of crystallinity of the original pure polylactide. In this case, the melting point remains almost unchanged.     

Structural and electronic properties of monolayer hydrogenated honeycomb III–V sheets from first-principles

Using first-principles calculations, we investigate the structural and electronic properties of monolayer hydrogenated honeycomb III–V sheets. The lattice constants and cohesive energies of the hydrogenated III–V (XY H₂, X=B, Al, Ga, and Y =N, P, As) sheets depend on the III–V elements and follow the same trend as the atomic radii of the elements. We find that the short lattice constants correspond to the large cohesive energies of the hydrogenated III–V sheets. Similar to the graphane sheet, the hydrogenated BP and BAs sheets prefer the chair conformation. While for the hydrogenated BN, AlN, AlP, and GaN sheets, the boat conformation is favored. For the hydrogenated AlAs, GaP, and GaAs sheets, the chair and boat conformations are degenerate structures. We obtain that all the hydrogenated III–V sheets are wide-gap semiconductors. With GW corrections, the band gaps of hydrogenated III–V sheets follow the order of nitrogen > phosphorous > arsenic compounds for both the chair and boat conformations.     

Dynamical Processes on Complex Networks,by A. Barrat,M. Barthélemy and A. Vespignani

The present state of theory and experiment on the gravity-induced electric field in metallic conductors and the electric field in accelerated metal conductors is reviewed. The relevant equations are derived in very simple approximations. The results depend on whether the deformation of the lattice of positive ions is neglected or is taken into account. Experimental results obtained with freely falling electrons in a cavity in the metal do not agree with the measurements of potentials on rapidly spinning metal rotors. Older direct measurements of the specific charge of carriers in metallic conductors are also mentioned.     

Electrical Conductivity of Synthetic Quartz Crystals at High Temperature and Pressure from Complex Impedance Measurements

An electrical conductivity measurement system under high-pressure conditions with a multi-anvil high-pressure apparatus by an ac complex impedance method was set up.With this system,we have successfully measured the electrical conductivity of synthetic quartz under pressure up to approximately 1.0GPa in the temperature range 661-987K.The values of electrical conductivity decrease with the increasing pressure and increase with the increasing temperature.The activation enthalpies for the α-quartz crystals are 1.10-1.28eV.The electrical conductivity of α-quartz is ionic,with Na ions moving in channels parallel to the c-axis being the predominant current carrier.     

Towards sustainable micro-pollutants’ removal from wastewaters: caffeine solubility,self-diffusion and adsorption studies from aqueous solutions into hydrochars

ABSTRACT

Hydrochars obtained via hydrothermal carbonisation of pistachio shells are both a sustainable and an efficient alternative to commercial activated carbons for the removal of micro-pollutants from wastewaters that are difficult to handle by conventional treatments. Here a combined experimental and molecular simulation approach is adopted for the study of the caffeine/hydrochars aqueous systems. This case study serves to tune a general framework for the rational customisation of surface functional groups on hydrochars for the selective adsorption of micro-pollutants from wastewaters. Caffeine’s solubility, self-diffusion and adsorption results from aqueous solutions at relevant conditions are presented. Insights about the role of surface functional groups over the caffeine adsorption mechanism into hydrochars are gained and discussed.     

The deformation texture ofβ-Sn III. Derivation of texture from elements of plastic deformation

The theoretical derivation of compression and rolling textures in -tin has been carried out for a different part in the deformation by slip and twinning for two different sets of slip systems given in the literature. The textures derived theoretically were compared with the compression and rolling textures measured in -tin in [6] and [7]. The dependence of the texture produced on the temperature of deformation is explained.     

ωN final state interactions and ω-meson production from heavy-ion collisions

We calculate the elastic and inelastic ωN→ωN, →πN, →ρN, →ρπN, →ππN, →σN reactions within a boson exchange approximation where the ωρπ coupling constant and form factor are fixed by the reaction πN→ωN in comparison to the experimental data. We find rather large ωN cross sections at low relative momenta of the ω-meson which leads to a substantial broadening of the ω-meson width in nuclear matter. The implications of the ωN final state interactions are studied for ω production in ¹²C +¹²C, ⁴⁰Ca +⁴⁰Ca and ⁵⁸Ni +⁵⁸Ni reactions at about 2 · A GeV within the HSD transport approach; the drastic changes of the transverse mass spectra relative to a general m _T-scaling (for π⁰ and η mesons) might be controlled experimentally by the TAPS Collaboration. Received: 28 April 1999 / Revised version: 7 June 1999     

Modular Invariants, Graphs and α-Induction¶for Nets of Subfactors. III

In this paper we further develop the theory of α-induction for nets of subfactors, in particular in view of the system of sectors obtained by mixing the two kinds of induction arising from the two choices of braiding. We construct a relative braiding between the irreducible subsectors of the two “chiral” induced systems, providing a proper braiding on their intersection. We also express the principal and dual principal graphs of the local subfactors in terms of the induced sector systems. This extended theory is again applied to conformal or orbifold embeddings of SU(n WZW models. A simple formula for the corresponding modular invariant matrix is established in terms of the two inductions, and we show that it holds if and only if the sets of irreducible subsectors of the two chiral induced systems intersect minimally on the set of marked vertices, i.e. on the “physical spectrum” of the embedding theory, or if and only if the canonical endomorphism sector of the conformal or orbifold inclusion subfactor is in the full induced system. We can prove either condition for all simple current extensions of SU _{( n )} and many conformal inclusions, covering in particular all type I modular invariants of SU(2) and SU(3), and we conjecture that it holds also for any other conformal inclusion of SU _{( n )} as well. As a by-product of our calculations, the dual principal graph for the conformal inclusion SU(3)₅⊂SU(6)₁ is computed for the first time. Received: 24 December 1998 / Accepted: 22 February 1999     

Optical properties of bicyclometalated Ir(III) and Rh(III) complexes of benzo[h]quinoline with (N∧S)− and (N∧O)− chelating ligands

[M(bzq)₂(N∧X)] complexes (M = Rh(III), Ir(III); (bzq)^? is the deprotonated form of benzo[h]quinoline, and (N∧X)^? are 2-thiolpyridine, 2-hydroxypyridine, and 2-thiolbenzothiazole ions) are studied by absorption and emission spectroscopy and voltammetry. The long-wavelength absorption bands of [Rh(bzq)₂(N∧X)] in the range of 420–424 nm are attributed to the optical metal-to-ligand charge transfer (MLCT) transitions, while the low-temperature (77 K) phosphorescence in the range of 490–610 nm is assigned to the intraligand (IL) transition of the {Rh(bzq)₂} metal-complex fragment. The phosphorescence of the [Ir(bzq)₂(N∧X)] complexes in liquid solutions in the range of 585–675 nm is assigned to the radiative MLCT transition, while the low-temperature (77 K) phosphorescence occurs from the thermally nonequilibrium MLCT and IL excited states of the {Ir(bzq)₂} metal-complex fragment.