Superconducting state parameters of ternary amorphous superconductors

The theoretical investigations of the superconducting state parameters (SSP) viz. electron-phonon coupling strength λ, Coulomb pseudopotential μ^?, transition temperature T_C, isotope effect exponent α and effective interaction strength N_OV of (Ni₃₃Zr₆₇)_1 − xM_x (x = 0, 0.05, 0.1, and 0.15, M = Cu) ternary amorphous superconductors have been reported using Ashcroft's empty core (EMC) model potential. Five local field correction functions proposed by Hartree (H), Taylor (T), Ichimaru-Utsumi (IU), Farid et al. (F) and Sarkar et al. (S) are used in the present investigation to study the screening influence on the aforesaid properties. The T_C obtained from Sarkar et al. (S) local field correction function is found in excellent agreement with available theoretical data. Quadratic T_C equation has been proposed, which provides successfully the T_C values of ternary amorphous alloys under consideration. Also, the present results are found in qualitative agreement with other such earlier reported data, which confirm the superconducting phase in the superconductors.     

Thermodynamic assessment of the Cu‐Mg‐Si system in its copper‐rich region

A thermodynamic assessment of the ternary Cu‐Mg‐Si system was made in its copper‐rich region in relation with the development of a thermodynamic database for Cu‐Mg alloys. The adjustable parameters of the binary end‐systems (Cu‐Mg, Cu‐Si and Mg‐Si) were taken from the literature and those of the Cu‐Mg‐Si system were optimized using experimental thermodynamic and topological data. For the sake of simplicity, the solution phases were described with the substitutional solution model and the intermetallic compounds were treated as plain semi‐stoichiometric phases ((A,B)_pC_q‐type). The assessment developed is applicable for magnesium contents up to 20 wt% (i.e. magnesium mole fractions ≈0.4) and silicon contents up to 16 wt% (i.e. silicon mole fractions ≈0.3). (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Viscosity of liquid Co–Sn alloys: thermodynamic evaluation and experiment

Shear viscosity measurements were performed for liquid Co–Sn alloys over a wide temperature range above the respective liquidus temperatures. A high temperature oscillating-cup viscometer was used. It was found experimentally that viscosity as a function of temperature obeys an Arrhenius law. The data were compared with calculated values, obtained from different thermodynamic approaches. A good agreement was found between experimental results and calculated ones by the Budai–Benkö–Kaptay model.     

Thermodynamic and surface properties of Ge–Ga and Ge–Sb liquid alloys

Thermodynamic and surface properties of Ge–Ga and Ge–Sb liquid alloys have been studied using statistical mechanical formulations based on complex formation and that based on the concept of layered structure near the interface. The study showed that low level of complex formation of the form Ge _{2 Sb} exists in Ge–Sb toward the Ge-rich end of the concentration range and the surface properties of Ge–Ga are almost equal to their corresponding bulk equivalent.     

Water Opening Address in the Presence of His Majesty the King of Belgium

Abstract

Solvay conferences aim to have two main characteristics. In planning them, our Scientific Council first chooses a unifying theme to link together diversified lines of scientific research, in which recent advances have been rapid. Leading scientists concerned with these advances are then invited from all over the world to Brussels, to present their successes—and their difficulties—to one another and to a small audience also specially invited. As is well known, spearhead advances in modern science must concentrate their attack on a fairly narrow front to make effective progress. But this very concentration often leads to a spread of advances in widely separated directions, like the fingers of a starfish. Those moving along one finger of the star can be wastefully ignorant about the other fingers. At Solvay conferences, by bringing experts in different lines together, our purpose is to encourage cross-communication of suggestive ideas and to promote mutual borrowing of scientific techniques. Measured by size, compared with very large scientific conferences now organized all over the world, Solvay conferences remain an “elitist” mode of scientific communication, in the sense that the number of invited experts is deliberately kept rather small, and that abundant time is provided for discussions. Discussion proceedings are fully recorded and their subsequent publication in book form is of course read by a much greater number of scientists afterwards.     

Structure of Al83Cu17 eutectic melt doped with Ni

Structure of (Al_0.83Cu_0.17)_{1??? x} Ni _x liquid alloys has been studied at different temperatures by means of X-ray diffraction method. Structure factors and pair correlation functions are analysed. It is shown that the addition of Ni to Al_0.83Cu_0.17 eutectic melt results in the increase of chemical ordering in the topology of atomic distribution.     

SECM and SKPFM Studies of the Local Corrosion Mechanism of Al Alloys – A Pathway to an Integrated SKP‐SECM System

Scanning Kelvin Probe Force Microscopy and Scanning Electrochemical Microscopy were applied for the investigation of localized corrosion on heterogeneous aiming on the investigation of the possible correlation between the local surface potential differences, measured by the Kelvin probe technique in ambient conditions, and corrosion during immersion in a corrosive electrolyte. A model sample mimicking the interaction of Al and Cu in Al alloys was chosen to demonstrate the complementary nature of the information received from SKPFM and SECM. The necessary prerequisites for a future integration of SKP and SECM into a single set‐up are discussed.     

在充放电循环过程中Ni/MH电池正负极的结构和性能变化

本文对在连续进行充放电循环过程中Ni/MH电池的放电容量、中值电压与循环周期的关系以及电池正负极结构和性能的变化进行了研究。结果表明：电池在循环过程中正极活性物质基本构型未变化，而负极储氢合金表面逐渐生成了La(OH)₃、Al(OH)₃、LiMnO₂，正负极活性物质随循环次数的增加不断发生粉化，这些都是导致Ni/MH电池放电性能下降的主要因素。