Gravity Induced Absorption Changes in <Emphasis Type="Italic">Phycomyces blakesleanus</Emphasis> and Coleoptiles of <Emphasis Type="Italic">Zea mays</Emphasis> as Measured on the Drop Tower in Bremen (FRG)

Various spectroscopic experiments performed on the AIRBUS ZERO G in the years 2002 to 2007 clearly exhibited optical reflection changes as a result of gravitational changes (GIAC = Gravity Induced Absorption Change) in Phycomyces sporangiophores and corn coleoptiles. GIACs that occurred during flight parabolas in response to hyper- and microgravity were detected by a micro dual wavelength spectrometer (MDWS) for wavelengths pairs in the visible and the near infrared. We assume that GIACs indicate redox-changes of electron transport components such as flavins and cytochromes. Because microgravity on the AIRBUS 300 ZERO G only amounts to moderate values of ±4 ×10^− 2 g, i.e. far below sensitivity of the MDWS, we performed an experiment on the drop tower in Bremen (Germany) that generates microgravity as low as 4 ×10^− 5 g for 4.7 s. We detected small but significant GIACs during the microgravity phase, different in various specimen.     

Combination of <Emphasis Type="Italic">Eigenfactor</Emphasis><Superscript>TM</Superscript> and <Emphasis Type="Italic">h-</Emphasis>index to evaluate scientific journals

The h-index and Eigenfactor ^TM values of top and specialized scientific/engineering journals are tabulated and combined to provide a simple graphical representation of the journals. The information may be tailored to specific uses by respective stakeholders to aid decision making processes with regards to scholarly research and scientific journal publications.     

Electrical characteristics of (<Emphasis Type="Italic">p</Emphasis>)3C-SiC-(<Emphasis Type="Italic">n</Emphasis>)6H-SiC heterojunctions

The electrical characteristics of (p)3C-SiC-(n)6H-SiC epitaxial heterostructures obtained by sublimation epitaxy in vacuum are studied. The band discontinuities are determined and the energy band diagram of the heterojunction is constructed. It is shown that the obtained heterostructure offers a promising material for high electron mobility transistors.     

The thermodynamic properties of liquid binary mixtures of <Emphasis Type="Italic">n</Emphasis>-alkanes: <Emphasis Type="Italic">n</Emphasis>-decane + <Emphasis Type="Italic">n</Emphasis>-hexadecane

Data on sound velocity are used for determining the density, the isobaric expansion coefficient, the isobaric and isochoric heat capacity, and the isothermal compressibility of liquid binary mixture of n-decane + n-hexadecane of three compositions in the temperature range of 298–433 K and pressure range of 0.1–100 MPa. The coefficients of Tait equation are calculated in the above-identified range of parameters. The calculation results are compared with experimental data on density. The divergence does not exceed 0.2% for the most reliable data.     

Electrical properties of photodiodes based on <Emphasis Type="Italic">p</Emphasis>-GaSb/<Emphasis Type="Italic">p</Emphasis>-GaInAsSb/<Emphasis Type="Italic">N</Emphasis>-GaAlAsSb heterojunctions

We have studied the electrical characteristics of photodiodes based on p-GaSb/p-GaInAsSb/N-GaAlAsSb heterojunctions and investigated the mechanisms of current transfer in these heterostructures at various temperatures. A comparison of the theoretical results and experimental data showed that the tunneling charge transfer mechanism dominates at low temperatures (T < 150 K) under both forward and reverse bias conditions. The tunneling current becomes a determining factor at an electric field strength in the p-n junction of no less that 10⁵ V/cm, which is related to a small bandgap width of the materials studied and low effective masses of electrons and holes.     

Nuclear-Physical Properties of <Superscript>105, 106<Emphasis Type="Italic">m</Emphasis>, 110<Emphasis Type="Italic">m</Emphasis></Superscript>Ag

The nuclear-physical properties of the nuclides ^{105, 106m,110m} Ag, which are concomitant nuclides in reactor production of ¹⁰³Pd and ¹⁰⁹Cd used in metrology of ionizing radiations and in nuclear medicine, were studied. The following quantities were determined by semiconductor X-ray and γ-ray spectrometry: the parameter K _α/K _β of X-ray K radiation accompanying the decay of ^110m Ag and the intensities of γ-ray quanta with the energies of 280 and 345 keV (¹⁰⁵Ag); 430, 451, and 512 keV (^106m Ag); 658, 764, 885, 938, and 1384 keV (^110m Ag). The half-lives determined using the above γ-ray lines are as follows: T _1/2(¹⁰⁵Ag) = 41.2 ± 0.1 days; T _1/2(^106m Ag) = 8.30±0.07 days. The errors are given for 95% confidence level.__________Translated from Radiokhimiya, Vol. 47, No. 1, 2005, pp. 31–34.Original Russian Text Copyright © 2005 by Popov, Zakharova, Sadulin, Andreev, Pakhomov.     

<Emphasis Type="Italic">hg</Emphasis>-index: a new index to characterize the scientific output of researchers based on the <Emphasis Type="Italic">h</Emphasis>- and <Emphasis Type="Italic">g</Emphasis>-indices

To be able to measure the scientific output of researchers is an increasingly important task to support research assessment decisions. To do so, we can find several different measures and indices in the literature. Recently, the h-index, introduced by Hirsch in 2005, has got a lot of attention from the scientific community for its good properties to measure the scientific production of researchers. Additionally, several different indicators, for example, the g-index, have been developed to try to improve the possible drawbacks of the h-index. In this paper we present a new index, called hg-index, to characterize the scientific output of researchers which is based on both h-index and g-index to try to keep the advantages of both measures as well as to minimize their disadvantages.     

Magneto-Peltier cooling of single-crystal Bi<Subscript>1-<Emphasis Type="Italic">X</Emphasis></Subscript>Sb<Subscript><Emphasis Type="Italic">X</Emphasis></Subscript> (<Emphasis Type="Italic">X </Emphasis>= 0.12 and 0.15) alloys

The cooling temperatures of rectangular parallelepiped Bi_1-X Sb _X (X = 0.12 and 0.15) single-crystals with the same thickness of t = 2 mm but different width W were measured at 113 K and 290 K as a function of electric current in the magnetic field B up to 2.17 T. The magnetic field was aligned along the thickness t of a sample and the current flows along its length L through the copper leads soldered to both end surfaces of cross section (W × t), where W, t and L are parallel to the binary, bisector and trigonal axes of the single-crystal, respectively. The thermoelement was not in contact with a heat sink. The cooling temperature of Bi_0.85Sb_0.15 at 290 K was increased with an increase of B and was almost symmetric for the reverse of the field direction, while at 113 K it exhibited a maximum at B = ±0.25 T and a strong asymmetry for the field direction. The largest maximum cooling temperature ΔT _max of Bi_0.85Sb_0.15 was achieved when a thermoelement has optimum dimensions so that heat energy is hardly generated at the cold side. When the single-crystal Bi_0.85Sb_0.15 alloy has optimum dimensions of L = 15 mm, W = 4 mm and t = 2 mm, the ΔT _max at 290 K increased from 4.2 K in B = 0 T to 9.6 K in B = +2.17 T, so that it exceeded ΔT _max values of 5.7 K obtained for a typical Bi₂Te₃ and 8.5 K measured previously for Bi single-crystal in B = +2.17 T.     

Pre-exponential factor in<Emphasis Type="Italic">a</Emphasis>-Se<Subscript>75</Subscript>In<Subscript>25-<Emphasis Type="Italic">x</Emphasis></Subscript>Pb<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> thin films

Temperature dependence of d.c. conductivity is studied ina- Se₇₅In_25-x Pb _x thin films wherex is varied from 0–10. From these measurements, the values of the pre-exponential factor (σ₀) and activation energy (ΔE) are calculated for each glassy alloy. An approximate linear dependence of ln σ₀ on AE is observed in this glassy system with good agreement between the expected and calculated σ₀ values using Meyer-Neldel rule. Linear dependence of ln σ₀ on ΔE in case of amorphous materials indicates that the conduction band tails a finite energy distance towards the valence band and Fermi level is controlled by fixed dominant hole levels deeper in the gap.     

<Emphasis Type="Italic">SH</Emphasis>-wave intromission concept

The existence of an SH-wave incidence angle for which the reflected amplitude is zero (SH-wave intromission angle) is established for the case of plane-wave scattering by a planar interface joining two homogeneous, isotropic, and linearly elastic half-spaces. Such an incidence angle is numerically shown to exist for two combinations of bimaterial interface properties. The SH-wave intromission angle is roughly parallel to the electromagnetic Brewster angle and the acoustic P-wave intromission angle, and the concept should find new applications for non-intrusive characterization of interfaces.     

A Statistical Model of <Emphasis Type="Italic">I</Emphasis><Subscript><Emphasis Type="Italic">c</Emphasis></Subscript> Changes for Bending Bi-2223 Tapes

Bi-2223 tape was one of the high-temperature superconductors with commercial applications. One of the applications was bending and winding Bi-2223 tape into solenoids to produce high magnetic fields. To study bending properties, three multifilamentary of Bi-2223 tapes sheathed with silver alloys were manufactured. Bending experiments for the tapes were performed, and critical currents I _c of tapes with definite bending radius were measured. And, current transferring mechanisms in filaments were analyzed, as well. Experimental results showed that silver alloy sheathed tapes had better bending properties than pure silver-sheathed one. On the contrary, to describe bending radius dependence of I _c , a statistical model was suggested. The model expected that bending radius dependence of I _c was following an exponential law that was quantitatively expressed by mathematic expressions. Bending dependence of I _c could be calculated from the expression and calculated results agreed with experimental data very well. Therefore, the suggested model has successfully explained the experimental results.     

The <Emphasis Type="Italic">α–β</Emphasis> Transition of Nitrogen

It is well-known that, aside from its triple point, nitrogen exhibits a solid-to-solid transition at about 35 K that is of some interest as a secondary reference temperature. During the recently published highly accurate measurements of the triple point of nitrogen (Metrologia 43, 435 (2006)), an extensive study was made also of the solid α–β transition of nitrogen, using both the continuous heating method and the pulse-heating method. This transition is of significantly lower quality than the triple point of nitrogen. A very high thermal resistance and a large time constant characterize the transition. Therefore, even the determination of the self-heating of the thermometer requires a very long time. A value of T ₉₀ = 35.620 K with an expanded uncertainty U = 8 mK for the coverage factor k = 2 was found, differing by +6 mK from the published CCT-recommended value. The reproducibility of the value was better than ± 5 mK. In addition to the temperature value found for the transition, a comparison is made with previous measurements on this point, and an overview is given of the available information about it.     

Structural,Superconducting, and Magnetic Properties of Y<Subscript>1- <Emphasis Type="Italic">x</Emphasis></Subscript>Dy<Subscript>x</Subscript>Rh<Emphasis Type="Italic">4</Emphasis>B<Emphasis Type="Italic">4</Emphasis> Borides

Samples with nominal compositions Y_1-x Dy_xRh₄B₄ are prepared by argon-atmosphere arc melting. The phase composition of the samples and the elemental compositions of the individual phases present are determined by x-ray diffraction and electron-probe x-ray microanalysis. The results indicate that increasing the dysprosium content of the starting mixture increases the percentage of the magnetic phase and reduces that of the superconducting phase in the samples. The electrical resistivity, magnetic susceptibility, and magnetic moment of the samples are measured between 1.6 and 30 K (magnetic fields of up to 14 T). The magnetic phase present in the samples with 0.2 ≤ × ≤ is shown to undergo ferromagnetic ordering at T _magn ≃ 13–13.5 K. The samples with 0 ≤ × ≤ 0.6 contain a superconducting phase with T _c from 9.1 to 5.0 K. The superconducting and magnetic properties of the Y_0.6Dy_0.4Rh₄B₄ sample are examined in detail.__________Translated from Neorganicheskie Materialy, Vol. 41, No. 6, 2005, pp. 676–681.Original Russian Text Copyright © 2005 by Burkhanov, Lachenkov, Kuz’micheva, Kovneristyi, Khlybov, Kostyleva, Tomilin.     

<Emphasis Type="Italic">t</Emphasis>-resilient functions and the partial exposure problem

The Wire-Tap Channel II introduced by L. H. Ozarow, A.D. Wyner was the first instance of a Partial Exposure Problem. General Exposure-Resilient Functions (ℓ-ERF) are known to be appropriate to provide a solution to the Partial Exposure Problem as long as random secret chains are to be protected. It is known that a perfect ℓ-ERF is nothing but a t-resilient function for t = n − ℓ, where n is the length of the exposed symbol-chain and t the largest number of symbols that an adversary is able to observe. We here manage to adapt the use of t-resilient functions for protecting messages against partial exposure. A solution to that problem had been given by the perfect local pseudo-random generator introduced by Maurer and Massey which is based upon a t-resilient function, but its use needs a secret key shared by the sender and the receiver. We are able to provide solutions to protect messages against Partial Exposure without using secret keys, for various ranges of parameters. Moreover low complexity algorithms are devised to that end.     

Generalization of <Emphasis Type="Italic">T</Emphasis> and <Emphasis Type="Italic">A</Emphasis> integrals to time-dependent materials: analytical formulations

This paper deals with the generalization of T-integral to crack growth process in viscoelastic materials. In order to implement this expression in a finite element software, a modelling form of this integral, called Aθ, is developed. The analytical formulation is based on conservative law, independent path integral, and a combination of real, virtual displacement fields, and real, virtual thermal fields introducing, in the same time, a bilinear form of free energy density F. According to the generalization of Noether’s method, the application of Gauss Ostrogradski’s theorem combined with curvilinear cracked contour, T _v is obtained. By introducing a volume domain around crack tip, the modelling expression Aθ is also defined.. Finally, the viscoelastic generalization through a thermodynamic approach, called A _v , is introduced by using a discretisation of the creep tensor according to a generalized Kelvin Voigt representation.     

Application of a sensitivity equation method to the <Emphasis Type="Italic">k</Emphasis>–<Emphasis Type="Italic">ε</Emphasis> model of turbulence

In this paper, we present some examples of sensitivity analysis for flows modeled by the standard k–ε model of turbulence with wall functions. The flow and continuous sensitivity equations are solved using an adaptive finite element method. Our examples emphasize a number of applications of sensitivity analysis: identification of the most significant parameters, analysis of the flow model, assessing the influence of closure coefficients, calculation of nearby flows, and uncertainty analysis. The sensitivity parameters considered are closure coefficients of the turbulence model and constants appearing in the wall functions.     

Optimization of the plastic relaxation of misfit stresses in Ge<Subscript>x</Subscript>Si<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript>/Si(001) (<Emphasis Type="Italic">x</Emphasis>≤0.61) heterostructures

High-quality Ge_xSi_1−x /Si(001) (x=0.38–0.61) heterostructures (600–750 nm thick) with plastically relaxed mechanical stresses were grown by low-temperature molecular beam epitaxy. The total film thickness was reduced by using low-temperature growth and two-step variation of the Ge_xSi_1−x layer composition. High quality of the heterostructure is achieved due to the fact that misfit stresses between layers are released by dislocations passing from the first layer to the second.     

Atomistic structure and strain relaxation in Czochralski-grown Si<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>Ge<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript> bulk alloys

The local atomistic structure in bulk Si_xGe_1−x alloys in the whole composition range 0 < x < 1 was investigated experimentally and theoretically. By extended X-ray absorption fine structure measurements in Czochralski-grown bulk SiGe crystals it is found that bulk SiGe is a random mixture and that the Ge–Ge, Ge–Si and Si–Si bond lengths maintain distinctly different lengths and vary in a linear fashion as a function of alloy composition across the entire composition range 0 < x < 1, in good agreement with expectations derived from the ab-inito electronic structure calculations. The results indicate that SiGe is a typical disorder material and that the bond lengths and bond angles are distorted with alloy composition in SiGe.     

Unusual magnetic and transport properties of the CMR Pr<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript>Ca<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>MnO<Subscript>3−<Emphasis Type="Italic">y</Emphasis></Subscript> system

The substituted nonstoichiometric perovskite Pr_1−x Ca _x MnO_3−y compounds have been synthesized by a standard combustion technique, which show uniphase solid solutions. The all samples of the Pr_1−x Ca _x MnO_3−y system show an orthorhombic crystal system and the cell volumes are decreased with increasing the larger amounts of substituted atoms or the increasing x values. The mixed valence of Mn ions is identified by the XAS (XANES/EXAFS) spectroscopy and the amounts of Mn⁴⁺ ions are determined by an iodometric titration method. Nonstoichiometric chemical formulas of the Pr_1−x Ca _x Mn_1−τ³⁺Mn_τ⁴⁺O_3−y compounds have been obviously formulated. Magnetic properties are investigated by SQUID and thus the Pr_1−x Ca _x MnO_3−y (x = 0.4, 0.6, and 0.8) compounds show the transition from antiferromagnetic state to paramagnetic state. The Pr_1−x Ca _x MnO_3−y (x = 0.0, 0.2, and 1.0) compounds show the transition from ferromagnetic state to paramagnetic state. The facts that Mn⁴⁺ contents play important roles in the magnetic ordering have been found out. The transport properties have been studied by the DC electrical conductivity measurement under magnetic fields of 0 G and 3 kG. Maximum and minimum MR ratios are 1016% of the Pr_0.6Ca_0.4MnO_2.846, and −77.5% of the PrMnO_3.021 compound, respectively.     

Ionic Conductivity of Ln<Subscript>2 + <Emphasis Type="Italic">x</Emphasis></Subscript>Zr<Subscript>2 − <Emphasis Type="Italic">x</Emphasis></Subscript>O<Subscript>7 − <Emphasis Type="Italic">x</Emphasis>/2</Subscript> (Ln = Sm-Gd) Solid Solutions

The electrical conductivity of Ln_{2 + x} Zr_{2 − x} O_{7 − x/2} (Ln = Sm-Gd) solid solutions prepared from mechanically activated Ln₂O₃ and ZrO₂ is shown to correlate with their structural properties. In the three systems, the x-T regions are determined in which electrical transport is dominated by oxygen-ion conduction. In the Sm₂O₃-ZrO₂ system, ionic conductivities from 5 × 10⁻⁴ to 6 × 10⁻³ S/cm at 740°C are found in Sm_{2 + x} Zr_{2 − x} O_{7 − x/2} with 26.6, 33.3, 35.5, 37, and 40 mol % Sm₂O₃ prepared at 1450, 1530, and 1600°C. Eu_{2 + x} Zr_{2 − x} O_{7 − x/2} and Gd_{2 + x} Zr_{2 − x} O_{7 − x/2} containing 33.3 to 37 mol % Ln₂O₃ have 740°C ionic conductivities of 10⁻³ to ∼7.5 × 10⁻³ and 10⁻³ to 7 × 10⁻³ S/cm, respectively. The activation energy of conduction in Ln_{2 + x} Zr_{2 − x} O_{7 − x/2} (Ln = Sm-Gd), E _a = 0.84–1.04 eV, increases with the atomic number of Ln and x. The highest ionic conductivity is offered by the stoichiometric Ln₂Zr₂O₇ (Ln = Sm-Gd) pyrochlores prepared at 1600°C, owing to the optimal concentration of Ln_Zr + Zr_Ln antistructure pairs (∼5–22%). The grains in the ceramic samples studied range in size from 0.5 to 2 µm.__________Translated from Neorganicheskie Materialy, Vol. 41, No. 8, 2005, pp. 975–984.Original Russian Text Copyright © 2005 by Shlyakhtina, Kolbanev, Knotko, Boguslavskii, Stefanovich, Karyagina, Shcherbakova.