Search results for "Binary alloy"
showing 8 items of 8 documents
The role of atomic static displacements in binary-alloy formation
2003
Abstract A microscopic approach to considering the influence of local atomic static displacements (LASD) on binary alloy thermodynamic properties has been developed. The explicit expression for the free energy of a disordered alloy is derived within the collective variables method. The LASD are shown to promote formation of a disordered alloy. The theory is illustrated by numerical calculations performed for alloys of the Ca–Ba system. Dependence of the alloy formation heat on temperature and concentration obtained numerically agrees perfectly with the experimental data.
Smart composite films of nanometric thickness based on copper-iodine coordination polymers. Toward sensors.
2018
One-pot reactions between CuI and methyl or methyl 2-amino-isonicotinate give rise to the formation of two coordination polymers (CPs) based on double zig-zag Cu2I2 chains. The presence of a NH2 group in the isonicotinate ligand produces different supramolecular interactions affecting the Cu-Cu distances and symmetry of the Cu2I2 chains. These structural variations significantly modulate their physical properties. Thus, both CPs are semiconductors and also show reversible thermo/mechanoluminescence. X-ray diffraction studies carried out under different temperature and pressure conditions in combination with theoretical calculations have been used to rationalize the multi-stimuli-responsive …
Structural and Magnetic Properties of Co-Fe Binary Alloy Monolayers on W(110)
2003
We present an experimental investigation of ${\mathrm{C}\mathrm{o}}_{x}{\mathrm{F}\mathrm{e}}_{1\ensuremath{-}x}$ monolayers grown on flat and stepped W(110) surfaces. Atomically resolved scanning tunneling microscopy and low energy electron diffraction reveal continuous miscibility and pseudomorphic growth of Co and Fe for $0\ensuremath{\le}xl0.6$. We observe short range ordered ${\mathrm{C}\mathrm{o}\mathrm{F}\mathrm{e}}_{3}$-$p(2\ifmmode\times\else\texttimes\fi{}2)$ and CoFe-$c(2\ifmmode\times\else\texttimes\fi{}2)$ structures in the pseudomorphic monolayer. High Co concentrations lead to a phase separation. The Curie temperature and the ferromagnetic Kerr signal at low temperatures decr…
Features of W production in p-p, p-Pb and Pb-Pb collisions
2017
We consider the production of inclusive W bosons in variety of high-energy hadronic collisions: p--p, p--$\overline{\rm p}$, p--Pb, and Pb--Pb. In particular, we focus on the resulting distributions of charged leptons from W decay that can be measured with relatively low backgrounds. The leading-order expressions within the collinearly factorized QCD indicate that the center-of-mass energy dependence at forward/backward rapidities should be well approximated by a simple power law. The scaling exponent is related to the small-$x$ behaviour of the quark distributions, which is largely driven by the parton evolution. An interesting consequence is the simple scaling law for the lepton charge as…
Random access with repeated contentions for emerging wireless technologies
2017
In this paper we propose ReCo, a robust contention scheme for emerging wireless technologies, whose efficiency is not sensitive to the number of contending stations and to the settings of the contention parameters (such as the contention windows and retry limits). The idea is iterating a basic contention mechanism, devised to select a sub-set of stations among the contending ones, in consecutive elimination rounds, before performing a transmission attempt. Elimination rounds can be performed in the time or frequency domain, with different overheads, according to the physical capabilities of the nodes. Closed analytical formulas are given to dimension the number of contention rounds in order…
Order and Disorder Phenomena at Surfaces of Binary Alloys
2000
We present recent Monte Carlo results on surfaces of bcc-structured binary alloys which undergo an order-disorder phase transformation in the bulk. In particular, we discuss surface order and surface induced disorder at the bulk transition between the ordered (DO3) phase and the disordered (A2) phase. An intricate interplay between different ordering and segregation phenomena leads to a complex surface behavior, which depends on the orientation of the surface under consideration.
2-(N,N-Diethylaminomethyl)-6,7-trihydroquinolinyl-8-ylideneamine-Ni(ii) chlorides: application in ethylene dimerization and trimerization
2020
A series of Ni(II) complexes with the general formula [2-((NEt2)Me)-8-{N(Ar)}C9H8N]NiCl2, where Ar = 2,6-Me2C6H3 in Ni1, 2,6-Et2C6H3 in Ni2, 2,6-i-Pr2C6H3 in Ni3, 2,4,6-Me3C6H2 in Ni4, 2,6-Et2-4-MeC6H2 in Ni5, and 2,4,6-t-Bu3C6H2 in Ni6, has been prepared using a one-pot reaction of 2-(N,N-diethylaminomethyl)-6,7-dihydroquinolin-8(5H)-one with the corresponding aniline and nickel dichloride hexahydrate. The resultant complexes were characterized using elemental analysis and FT-IR spectroscopy, while the mononuclear Ni1 and Ni3 were also the subject of single-crystal X-ray diffraction study. On activation with MMAO, the complexes Ni1–Ni6 displayed good activity in ethylene oligomerization, f…
Density functional theory description of random Cu-Au alloys
2019
Density functional alloy theory is used to accurately describe the three core effects controlling the thermodynamics of random Cu-Au alloys. These three core effects are exchange correlation (XC), local lattice relaxations (LLRs), and short-range order (SRO). Within the real-space grid-based projector augmented-wave (GPAW) method based on density functional theory (DFT), we adopt the quasinonuniform XC approximation (QNA), and take into account the LLR and the SRO effects. Our approach allows us to study the importance of all three core effects in a unified way within one DFT code. The results demonstrate the importance of the LLR term and show that going from the classical gradient level a…