Evidence of entropically driven C₆₀ fullerene aggregation in aqueous solution

In the present work, we report the first experimental evidence of entropically driven C₆₀ fullerene aggregation in aqueous solution, occurring with nearly zero enthalpy chang

Complexation of aromatic drugs with single-walled carbon nanotubes

We report a detailed study of the complexation of aromatic molecules and drugs with the surface of single-walled carbon nanotubes (SWCNTs, the diameter and the length ranges are 0.5-2 nm and 1-5 μm, respectively) in terms of equilibrium binding constants, K. It is found that the binding constants have magnitudes of the order of 104-105 M-1 and that there is some ligand specificity to the SWCNT surface depending on the structure of the aromatic molecul

First Principles Investigation of Magnetic Properties of Fe-Ni-Mn-Al Heusler Alloys

AbstractThe composition dependences of crystal lattice parameters, magnetic moments and magnetic exchange parameters in FexNi2−xMn1+y Al1−y (0.0 ≤ x ≤ 2.0; 0.0 ≤ y ≤ 0.6) Heusler alloys are investigated with the help of first principles calculations. Our simulations have shown that crystal lattice parameter is decreased with Fe content (x) increasing. Our calculations show that increase of Fe content (x) leads increasing of magnetic exchange interactions between Mn atoms at regular positions and Mn atoms at Al positions and change of interaction sign from antiferromagnetic type to ferromagnetic one for Fe content x ≥ 1.4. Competitive behavior between ferromagnetic and antiferromagnetic interactions shows that these alloys have a complex magnetic structure. Calculated data for crystal lattice parameter, magnetic moment and magnetic exchange parameters for pure compounds (x = 0.0 and x = 2.0) are in an agreement with theoretical and experimental data

Magnetocaloric and Magnetic Properties of Ni\u3csub\u3e2\u3c/sub\u3eMn\u3csub\u3e1-x\u3c/sub\u3eCu\u3csub\u3ex\u3c/sub\u3eGa Heusler Alloys: an Insight from the Direct Measurements and \u3ci\u3eab initio\u3c/i\u3e and Monte Carlo Calculations

We calculated magnetic exchange constants and magnetocaloric properties of Ni2Mn1-xCuxGa Heusler alloys by ab initio and Monte Carlo methods. The ab initio study of the influence of the Cu excess x on the strength of magnetic interactions revealed that Cu weakens Mn-Ni interaction and has a complex impact on the Mn-Mn interactions. Theoretically calculated magnetic phase diagram of Ni2Mn1-xCuxGa is in a good agreement with available experimental data. Calculated by the Monte Carlo method the isothermal magnetic entropy change Delta Smag in a Ni2Mn0.75Cu0.25Ga alloy is significantly smaller around the coupled magnetostructural phase transition temperature than the reported earlier experimental Delta Smag. This discrepancy is ascribed to an overestimation of the experimental Delta Smag at the magnetostructural phase transition. Theoretically determined adiabatic temperature change Delta Tad in Ni2Mn0.75Cu0.25Ga agrees well with Delta Tad measured experimentally by a direct method