Evaluation of dew-water density by the Monte Carlo method

To construct a physical model of water vapor condensation with the formation of dew water, a geometrically based Monte Carlo method was developed. The hit and geometrical density functions of random space filling with identical spheres were determined. The parameters of these functions is the minimum allowable approach OO _min of spheres and their excess in comparison with the space capacity. The specificity of dew-water molecules and hydrogen bonds (HBs) between them appears at 2/3L _b < OO _min < 2L _b, where L _b is the HB length. As the approach OO _min = L _b, the random filling density does not exceed the packing density in the sphere models of I _h and I _c ices. The densities characteristic of the sphere model of water molecule packing in these ices are achievable at OO _min ≈ 0.8L _b and/or a significant HB kink, as well as at vapor supersaturation (excess of molecules over the space capacity).     

Coherent inelastic processes on nuclei at ultrarelativistic energies

The coherent inelastic processes of the type a → b, which may take place in the interaction of hadrons and γ quanta with nuclei at very high energies (the nucleus remains the same), are theoretically investigated. For taking into account the influence of the nucleus matter, the optical model, based on the conception of the refraction index, is used. Analytical formulas for the effective cross section σ _coh (a → b) are obtained, taking into account that, at ultrarelativistic energies, the main contribution into σ _coh (a → b) is provided by very small transferred momenta in the vicinity of the minimal longitudinal momentum transferred to the nucleus. It is shown that the cross section σ _coh (a → b) may be expressed through the “forward” amplitudes of inelastic scattering f _a+N+b+N (0) and elastic scattering f _a+N+a+N(0), f _b+N+b+N(0) on a separate nucleon, and it depends on the ratios L _a /R and L _b /R (L _a and L _b are the mean lengths of the free path in the nucleus matter for the particles a and b, respectively, and R is the nucleus radius). In particular, when L _a /R ≫ 1, but L _b /R ≪ 1 (or L _a /R ≪ 1, but L _b /R ≫ 1), σ _coh (a → b) is equal to the ratio of the “forward” cross sections of inelastic scattering a + N → b + N and elastic scattering of the particle b (or a) on a nucleon, multiplied by the cross section of scattering on the “black” nucleus πR ². When both conditions L _a /R ≫ 1 and L _b /R ≫ 1 are satisfied, σ _coh (a → b) is proportional to the factor R ⁴/k ², where k is the initial energy of particle a in the laboratory frame. The text was submitted by the authors in English.     

Carbon acceptor luminescence in type-I GaAs/AlAs ultrathin-layer superlattices

The luminescence associated with residual carbon acceptors in type-I (direct-gap) ultrathin-layer superlattices (UTLS) with well and barrier widths of 22.7<L _z<25.2 Å and 11.5<L _b<14.0 Å, respectively, is composed two lines reflecting the on-center and on-edge state of the impurities. In these narrow wells the on-center acceptor binding energy increases to 60 meV in agreement with theoretical calculations for GaAs single quantum wells using a valence band offset of 500 meV. While the binding energy of the on-center state does not vary significantly within the studied L _z and L _b range, the on-edge state shows a strong dependence on the very narrow barrier width. This increase of the acceptor binding energy makes the energy position of the impurity-related luminescence in UTLS very sensitive to the actual barrier height. Investigation of the impurity-related luminescence thus provides a versatile tool to determine the band offset ratio at the heterojunction.     

Positron annihilation response and broadband dielectric spectroscopy: Salol

A phenomenological analysis of the ortho-positronium (o-Ps) annihilation from positron annihilation lifetime spectroscopy (PALS) and the dynamics from broadband dielectric spectroscopy (BDS) are reported on a small molecular glass former of intermediate H-bonding and fragility: salol. The dielectric spectra extend over a very broad frequency range of about 2 × 10⁻²−3.5 × 10¹¹ Hz, providing information on the α-relaxation, the secondary relaxation giving rise to the excess wing, and the shallow high-frequency minimum in the micro- to milli-meter wave range. A number of empirical correlations between the o-Ps lifetime, τ ₃(T), and the various spectral and relaxation features have been observed. Thus, the phenomenological evaluation of the τ ₃(T) dependence of the PALS response of the amorphous sample reveals three characteristic PALS temperatures: T _g ^PALS, T _b1 ^L = 1.15T _g ^PALS and T _b2 ^L = 1.25T _g ^PALS, which are discussed in relation to similar findings for some typical small molecular vdW- and H-bonded glass formers. A slighter change of the slope at T _b1 ^L appears to be related to the transition from excess wing to the primary α-process-dominated behavior, with the secondary process dominating in the deeply supercooled liquid state below T _b1 ^L . The high-temperature plateau effect in the τ ₃(T) plot occurs at T _b2 ^L and agrees with the characteristic Stickel temperature, T _B ^ST, marking a qualitative change of the primary α process, but it does not follow the relation T _b2 ^L < T _α [τ ₃(T _b2) < τ _α ]. Both effects at T _b1 ^L and T _b2 ^L correlate with two crossovers in the spectral shape and related non-exponentiality parameter of the structural relaxation, β _KWW. Finally, the application of the two-order parameter (TOP) model to the structural relaxation as represented by the primary α relaxation times from BDS leads to the characteristic TOP temperature, T _m ^c , close to T _b1 from PALS. Within this model the phenomenological interpretation is offered based on changes in the probability of occurrence of solid-like and liquid-like domains to explain the dynamic as well as PALS responses. In summary, all the empirical correlations support further very close connections between the PALS response and the dielectric relaxation behavior in small molecule glass formers.     

Study of the influence of the injection section on the stability of a high-current relativistic electron beam propagating through the gaseous medium of a plasmochemical reactor

Results are presented from experimental study of the influence of the injection section on the stability of a high-current relativistic electron beam (REB) propagating through the gaseous medium of a plasmochemical reactor (PR). An REB with the electron energy E _e =1 MeV, beam current I _b =10–22 kA, and pulse duration t=60 ns was generated by the Tonus accelerator and, then, injected into a 0.1-m-diameter PR filled with air. The PR consisted of two sections with lengths L ₁= 0.3–1.0 m and L ₂=1.1–2.5 m; the total length of the system was no longer than 3.5 m. The first section was filled with air at a pressure of P ₁=0.8–1.5 torr, and the pressure in the second section was varied within the range P ₂=0.1–760 torr. The current I _b of an REB passed through both sections of the PR was measured with the help of a sectioned vacuum Faraday cup. The transportation efficiency of the beam was determined as the ratio I _b /I _inj, where I _inj is the beam current measured at the point of injection into the PR. It is shown that, for the optimal dimensions of the first PR section, it has a stabilizing action on the REB with a current density of up to 3 kA/cm², which makes it possible to increase the effective length of the second (working) PR section, which is filled with a gas at various pressures, to L ₂=(25–35)L _bet, where L _bet is the beam betatron length.     

Effect of strain-induced order-parameter coupling on the ferroelastic behaviour of lead phosohate-arsenate

The phase diagram of ferroelastic Pb₃(PO₄)₂-Pb₃(AsO₄)₂ has been reinvestigated and four new phase transitions have been found from birefringence measurements at low temperatures. The first-order phase transition between the phases b (C2/c) and c (P2₁/c) in Pb₃(AsO₄)₂ becomes continuous with increasing P-content.

In Pb₃(P_0.2As_0.8O₄)₂, a monoclinic intermediate phase b_c was identified from the measurements of the spontaneous strain, the morphic birefringence and the orientation of the optical indicatrix.

The experimental results are interpreted using the Landau theory of biquadratically coupled order parameters. Phase b is related to an order parameter of L-point symmetry in the paraelastic phase a (3). The phase c is due to a critical F-point in 3. The intermediate phase b_c is the consequence of the biquadratic coupling of order parameters with L-and F-point symmetry.

Model calculations for Pb₃(P_0.2As_0.8O₄)₂ relate the free energies of the phases b, b_c and c and the temperature dependence of the order parameters with the measured optical birefringence. They explain well the occurrence of an intermediate phase with monoclinic symmetry from the movement of the thermodynamic stability point in the vector space diagram of order parameters.     

Precession of angular momentum vector in a slowly rotating Kerr metric

Specializing Penrose and Floyd's resultF _ab;c =F _[ab;c] to the Kerr metric, we explicitly construct the skew symmetric tensorF _ab and Carter's quadratic integral of geodesic motion.F _ab is then shown to be closely related to the orbital angular momentum encountered in Newtonian mechanics. Furthermore, F_ab can be decomposed additively intoL _ab andM _ab , whereL _ab has the character of angular momentum, andM _ab exists only for a nonzero rotation parameter,a, of the Kerr metric. It turns out that the equation of precession = _a ^b L _b has a nontrivial solution only for the case of a slowly rotating Kerr metric valid to first order in rotation parameter. In this case, Carter's integral can be interpreted as the squared length of the precessing angular momentum vectorL _a =L _a ^b P _b . The equation of precession is solved, and a vector ^a describing angular velocity of precession is derived.     

Charm and bottom baryons in nonperturbative quark dynamics

We use the field correlator method in QCD to calculate the masses of Σ _c , Ξ _c , and recently observed Σ _b , Ξ _b baryons and their orbital excitations. The text was submitted by the authors in English.     

Evaluation of Effective Resistances in Pseudo-Distance-Regular Resistor Networks

The effective resistance or two-point resistance between two nodes of a resistor network is the potential difference that appears across them when a unit current source is applied between the nodes as terminals. This concept arises in problems which deal with graphs as electrical networks including random walks, distributed detection and estimation, sensor networks, distributed clock synchronization, collaborative filtering, clustering algorithms and etc. In the previous paper (Jafarizadeh et al. in J. Math. Phys. 50:023302, 2009) a recursive formula for evaluation of effective resistances on the so-called distance-regular networks was given based on the Christoffel-Darboux identity. In this paper, we consider more general networks called pseudo-distance-regular networks or QD type networks, where we use the stratification of these networks and show that the effective resistances between a given node, say α, and all of the nodes β belonging to the same stratum with respect to α, are the same. Then, based on the spectral techniques, for those α,β’s which satisfy L^-1_aa=L^-1_bbL^{-1}_{\alpha\alpha}=L^{-1}_{\beta\beta} (L ⁻¹ is the pseudo-inverse of the Laplacian of the network), an analytical formula for effective resistances R_ab^(m)R_{\alpha\beta^{(m)}} (the equivalent resistance between terminals α and β, so that β belongs to the m-th stratum with respect to α) is given in terms of the first and second orthogonal polynomials associated with the network. From the fact that in distance-regular networks, L^-1_aa=L^-1_bbL^{-1}_{\alpha\alpha}=L^{-1}_{\beta\beta} is satisfied for all nodes α,β of the network, the effective resistances R_ab^(m)R_{\alpha\beta^{(m)}} for m=1,2,…,d (d is diameter of the network which is the same as the number of strata) are calculated directly, by using the given formula.     

Extended soft X-ray emission spectroscopy: quantitative assessment of emission intensities

Soft X‐ray emission spectroscopy (SXES) in the energy range between 150 eV and 1500 eV has typical attenuation lengths between tens and a few hundred nanometres. In this work the transmission of soft X‐rays in synchrotron‐based SXES has been quantitatively analysed using specially prepared layer samples. The possibility of extending the standard qualitative analysis of SXES by exploiting the information underlying the emission intensity was examined for thin layer structures. Three different experiment series were accomplished with model layer systems based on different sulfur‐containing substrates: (i) MoS₂, (ii) CuInS₂, (iii) Cu(In,Ga)(S,Se)₂. The absorption of the S L_2,3 emission line by ZnO cover layers of up to 80 nm thickness was monitored and compared with theoretical expectations. By comparison with a reference intensity recorded from a bare substrate, the attenuation of the S L_2,3 emission could be used to accurately determine the ZnO overlayer thickness up to a critical thickness, depending on the set‐up and the net S L_2,3 emission intensity. The results from these local energy‐resolved spot measurements were compared with spatially resolved scans of the integral S L_2,3 emission intensity over areas of several mm². In the scan images the attenuation of the S L_2,3 emission intensity clearly reflects the local ZnO layer thickness. From the attenuation the ZnO layer thicknesses were calculated and compared with ellipsometric measurements and were found to be in excellent agreement. These results demonstrate the benefits of a quantitative analysis of SXES, making it an even more powerful tool for examining buried interfaces and for monitoring lateral inhomogeneities.     

Universality Limits of a Reproducing Kernel for a Half-Line Schrödinger Operator and Clock Behavior of Eigenvalues

We extend some recent results of Lubinsky, Levin, Simon, and Totik from measures with compact support to spectral measures of Schrödinger operators on the half-line. In particular, we define a reproducing kernel S _L for Schrödinger operators and we use it to study the fine spacing of eigenvalues in a box of the half-line Schrödinger operator with perturbed periodic potential. We show that if solutions u(ξ, x) are bounded in x by ${e^{\epsilon x}}We extend some recent results of Lubinsky, Levin, Simon, and Totik from measures with compact support to spectral measures of Schr?dinger operators on the half-line. In particular, we define a reproducing kernel S _L for Schr?dinger operators and we use it to study the fine spacing of eigenvalues in a box of the half-line Schr?dinger operator with perturbed periodic potential. We show that if solutions u(ξ, x) are bounded in x by e^ex{e^{\epsilon x}} uniformly for ξ near the spectrum in an average sense and the spectral measure is positive and absolutely continuous in a bounded interval I in the interior of the spectrum with x₀ ? I{\xi_0\in I}, then uniformly in I,

\fracSL(x0 + a/L, x0 + b/L)SL(x0, x0)? \fracsin(pr(x0)(a - b))pr(x0)(a - b),\frac{S_L(\xi_0 + a/L, \xi_0 + b/L)}{S_L(\xi_0, \xi_0)}\rightarrow \frac{\sin(\pi\rho(\xi_0)(a - b))}{\pi\rho(\xi_0)(a - b)},      14. Flavor symmetry L μ-L τ and quasidegenerate neutrinos      W. Rodejohann  M. A. Schmidt 《Physics of Atomic Nuclei》2006,69(11):1833-1841 Current data implies three simple forms of the neutrino mass matrix, each corresponding to the conservation of a nonstandard lepton charge. While models based on L e and L e-L μ-L τ are well known, little attention has been paid to L μ-L τ. A low-energy mass matrix conserving L μ-L τ implies quasidegenerate light neutrinos. Moreover, it is μ-τ symmetric and therefore (in contrast to L e and L e-L μ-L τ) automatically predicts maximal atmospheric neutrino mixing and zero U e3. A seesaw model based on L μ-L τ is investigated and testable predictions for the neutrino mixing observables are given. Renormalization group running below and in between the seesaw scales is taken into account in our analysis, both numerically and analytically. The text was submitted by the authors in English.      15. Laminar and unstable burning velocities and Markstein lengths of hydrogen–air mixtures at engine-like conditions      S. Verhelst  R. Woolley  M. Lawes  R. Sierens 《Proceedings of the Combustion Institute》2005,30(1):209-216 Hydrogen offers an attractive alternative to conventional fuels for use in spark ignition engines. It can be burned over a very wide range of equivalence ratios and with considerable exhaust gas recirculation. These help to minimise pumping losses through throttleless operation and oxides of nitrogen (NOx) production through reduced temperature. Full understanding of hydrogen-fuelled engine operation requires data on the laminar burning rate of hydrogen–air residuals under a wide range of conditions. However, such data are sparse. The present work addresses this need for experimental data. Spherically expanding H2–air flames were measured at a range of temperatures, pressures, and equivalence ratios and with varying concentrations of residuals of combustion. Unstretched burning velocities, ul, and Markstein lengths, Lb, were determined from stable flames. At the higher pressures, hydrodynamic and diffusional-thermal instabilities caused the flames to be cellular from inception and prohibited the derivation of values of ul and Lb. The effect of pressure on the burning rate was demonstrated to have opposing trends when comparing stoichiometric and lean mixtures. The present measurements were compared with those available in the literature, and discrepancies were attributed to neglect, in some works, the effects of stretch and instabilities. From the present measurements, the effects of pressure, temperature, and residual gas concentration on burning velocity are quantified for use in a first step towards a general correlation.      16. Quantitative investigation of the two-photon absorption of Ruby-laser-light in various semiconductors      G. Kobbe  C. Klingshirn 《Zeitschrift für Physik B Condensed Matter》1980,37(1):9-12 With aQ-switched Ruby-laser (h v L =1.785 eV), the two-photon absorption (TPA) coefficient of various semiconductors is determined. The gap energy,E g , of these substances is lying in the range ofh v L <E g <2hv L . For all measurements the same experimental setup is used, and for the evolution of the data the real, time-dependent intensity of the laser pulse is taken. Thus, the existing discrepancies between the TPA-coefficients as determined by various authors with different experimental techniques can be settled.      17. Neutrino masses with broken L e ? L μ ? L τ and small θ 13      R. Franceschini 《Physics of Atomic Nuclei》2008,71(4):701-705       18. Anisotropy Effects in Nucleation for Conservative Dynamics      F. R. Nardi  E. Olivieri  E. Scoppola 《Journal of statistical physics》2005,119(3-4):539-595 We analyze metastability and nucleation in the context of a local version of the Kawasaki dynamics for the twodimensional it anisotropic Ising lattice gas at very low temperature. Let LsubsetZ2 be a sufficiently large finite box. Particles perform simple exclusion on L, but when they occupy neighboring sites they feel a binding energy U1<0 in the horizontal direction and U2<0 in the vertical direction; we assume U1ges U2. Along each bond touching the boundary of L from the outside, particles are created with rate rho=eDb and are annihilated with rate 1, where b is the inverse temperature and D>0 is an activity parameter. Thus, the boundary of L plays the role of an infinite gas reservoir with density rho. We take Din (U1,U1+U2) where the totally empty (full) configuration can be naturally associated to metastability (stability). We investigate how the transition from empty to full takes place under the dynamics. In particular, we identify the size and some characteristics of the shape of the it critical droplet/ and the time of its creation in the limit as btoinfty. We observe very different behavior in the weakly or strongly anisotropic case. In both case we find that Wulff shape is not relevant for the nucleation pattern.      19. Valence and conduction bands in MPS3 layered compounds studied by synchrotron radiation      V. Grasso  S. Santangelo  M. Piacentini 《Il Nuovo Cimento D》1986,8(3):263-278 Summary With the resonant photomeission technique we investigated the valence bands of FePS3 and NiPS3. The experimental results, support the ionic picture of the compounds and our previous identification of the valence band structures. The structures rapidly varying in intensity when the excitation energy is scanned across the Fe and NiM 2,3 absorption edge are associated to the transition metal 3d states; the nonresonating features are ascribed to the (P2P6)4− cluster states. With the yield technique we measured the high-resolution absorption spectra of the phosphorus and sulphur inner-core levels in Mn, Fe and Ni thiophosphates. TheL 2,3(P) andL 2,3(S) spectra are similar to each other in all the compounds and are interpreted in terms of the projected density of states of the conduction bands derived from the (P2S6)4− cluster states. To speed up publication, the authors of this paper have agreed to not receive the proofs for correction.      20. Symmetry aspect of the phase transitions in boracites      V. Dvořák  J. Petzelt 《Czechoslovak Journal of Physics》1971,21(11):1141-1152 The phase transitions in boracites are analysed by using the group-theoretical formulation of the Landau theory of phase transitions. It is shown that the orthorhombic, monoclinic and trigonal phase transitions could be induced by the same irreducible representation of the space groupT d 5 with the star determined by the wave vectork=1/2(b 1+b 2). The corresponding free energy function is constructed and the symmetry of normal modes is discussed.The authors thank Dr. V. Janovec of the Institute of Physics for valuable remarks to this paper.

Flavor symmetry L μ-L τ and quasidegenerate neutrinos

Current data implies three simple forms of the neutrino mass matrix, each corresponding to the conservation of a nonstandard lepton charge. While models based on L _e and L _e-L _μ-L _τ are well known, little attention has been paid to L _μ-L _τ. A low-energy mass matrix conserving L _μ-L _τ implies quasidegenerate light neutrinos. Moreover, it is μ-τ symmetric and therefore (in contrast to L _e and L _e-L _μ-L _τ) automatically predicts maximal atmospheric neutrino mixing and zero U _e3. A seesaw model based on L _μ-L _τ is investigated and testable predictions for the neutrino mixing observables are given. Renormalization group running below and in between the seesaw scales is taken into account in our analysis, both numerically and analytically. The text was submitted by the authors in English.     

Laminar and unstable burning velocities and Markstein lengths of hydrogen–air mixtures at engine-like conditions

Hydrogen offers an attractive alternative to conventional fuels for use in spark ignition engines. It can be burned over a very wide range of equivalence ratios and with considerable exhaust gas recirculation. These help to minimise pumping losses through throttleless operation and oxides of nitrogen (NO_x) production through reduced temperature. Full understanding of hydrogen-fuelled engine operation requires data on the laminar burning rate of hydrogen–air residuals under a wide range of conditions. However, such data are sparse. The present work addresses this need for experimental data. Spherically expanding H₂–air flames were measured at a range of temperatures, pressures, and equivalence ratios and with varying concentrations of residuals of combustion. Unstretched burning velocities, u_l, and Markstein lengths, L_b, were determined from stable flames. At the higher pressures, hydrodynamic and diffusional-thermal instabilities caused the flames to be cellular from inception and prohibited the derivation of values of u_l and L_b. The effect of pressure on the burning rate was demonstrated to have opposing trends when comparing stoichiometric and lean mixtures. The present measurements were compared with those available in the literature, and discrepancies were attributed to neglect, in some works, the effects of stretch and instabilities. From the present measurements, the effects of pressure, temperature, and residual gas concentration on burning velocity are quantified for use in a first step towards a general correlation.     

Quantitative investigation of the two-photon absorption of Ruby-laser-light in various semiconductors

With aQ-switched Ruby-laser (h v _L =1.785 eV), the two-photon absorption (TPA) coefficient of various semiconductors is determined. The gap energy,E _g , of these substances is lying in the range ofh v _L <E _g <2hv _L . For all measurements the same experimental setup is used, and for the evolution of the data the real, time-dependent intensity of the laser pulse is taken. Thus, the existing discrepancies between the TPA-coefficients as determined by various authors with different experimental techniques can be settled.     

Anisotropy Effects in Nucleation for Conservative Dynamics

We analyze metastability and nucleation in the context of a local version of the Kawasaki dynamics for the twodimensional it anisotropic Ising lattice gas at very low temperature. Let LsubsetZ² be a sufficiently large finite box. Particles perform simple exclusion on L, but when they occupy neighboring sites they feel a binding energy U₁<0 in the horizontal direction and U₂<0 in the vertical direction; we assume U₁ges U₂. Along each bond touching the boundary of L from the outside, particles are created with rate rho=e^Db and are annihilated with rate 1, where b is the inverse temperature and D>0 is an activity parameter. Thus, the boundary of L plays the role of an infinite gas reservoir with density rho. We take Din (U₁,U₁+U₂) where the totally empty (full) configuration can be naturally associated to metastability (stability). We investigate how the transition from empty to full takes place under the dynamics. In particular, we identify the size and some characteristics of the shape of the it critical droplet/ and the time of its creation in the limit as btoinfty. We observe very different behavior in the weakly or strongly anisotropic case. In both case we find that Wulff shape is not relevant for the nucleation pattern.     

Valence and conduction bands in MPS3 layered compounds studied by synchrotron radiation

Summary With the resonant photomeission technique we investigated the valence bands of FePS₃ and NiPS₃. The experimental results, support the ionic picture of the compounds and our previous identification of the valence band structures. The structures rapidly varying in intensity when the excitation energy is scanned across the Fe and NiM _2,3 absorption edge are associated to the transition metal 3d states; the nonresonating features are ascribed to the (P₂P₆)⁴⁻ cluster states. With the yield technique we measured the high-resolution absorption spectra of the phosphorus and sulphur inner-core levels in Mn, Fe and Ni thiophosphates. TheL _2,3(P) andL _2,3(S) spectra are similar to each other in all the compounds and are interpreted in terms of the projected density of states of the conduction bands derived from the (P₂S₆)⁴⁻ cluster states. To speed up publication, the authors of this paper have agreed to not receive the proofs for correction.     

Symmetry aspect of the phase transitions in boracites

The phase transitions in boracites are analysed by using the group-theoretical formulation of the Landau theory of phase transitions. It is shown that the orthorhombic, monoclinic and trigonal phase transitions could be induced by the same irreducible representation of the space groupT _d ⁵ with the star determined by the wave vectork=1/2(b ₁+b ₂). The corresponding free energy function is constructed and the symmetry of normal modes is discussed.The authors thank Dr. V. Janovec of the Institute of Physics for valuable remarks to this paper.