Complex magnetic ordering as a driving mechanism of multifunctional properties of Heusler alloys from first principles

First-principles calculations are used to study the structural, electronic and magnetic properties of (Pd, Pt)-Mn-Ni-(Ga, In, Sn, Sb) alloys, which display multifunctional properties like the magnetic shape-memory, magnetocaloric and exchange bias effect. The ab initio calculations give a basic understanding of the underlying physics which is associated with the complex magnetic behavior arising from competing ferro- and antiferromagnetic interactions with increasing number of Mn excess atoms in the unit cell. This information allows to optimize, for example, the magnetocaloric effect by using the strong influence of compositional changes on the magnetic interactions. Thermodynamic properties can be calculated by using the ab initio magnetic exchange parameters in finite-temperature Monte Carlo simulations. We present guidelines of how to improve the functional properties. For Pt-Ni-Mn-Ga alloys, a shape memory effect with 14% strain can be achieved in an external magnetic field.     

Synthesis and structure of complexes of phosphorus pentachloride with 4‐dimethylaminopyridine and n‐methylimidazole

Complexes of phosphorus pentachloride with 4‐dimethylaminopyridine and N‐methylimidazole were synthesized. The molecular structure of the phosphorus pentachloride complex with N‐methylimidazole was determined by single‐crystal X‐ray diffraction. In the cationic part of the complex, the phosphorus atom possesses four P Cl bonds within the range 2.109–2.148 Å and two cis‐P–N bonds (1.811 and 1.832 Å) with N‐methylimidazole and exhibits slightly distorted octahedral coordination with angles at phosphorus atom in the range 87.57°–91.50°. The relative stability of the cis and trans conformations of the complex was studied by DFT calculations. The chemical properties and reactivity of the compounds obtained are determined; their utility as condensing agents in the synthesis of amides from acids and amines was shown. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:171–177, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20392     

Identification of Unknown Filter in a Half-Strip

We consider the analogue of the classic Wiener filtering theory to a half-strip of complex domain. In this paper all test signal obtained that solving the filter identification problem for the Hardy spaces in a half-strip. This result can be used for the investigations of electrical, optical, acoustical signals.

     

Peculiarities of resonant interaction in paired impurity centers of 2-fluoronaphthalene in naphthalene

Abstract

Fluorescence and absorption spectra of the 2-fluoronaphthalene admixtures in naphthalene were studied at low temperature (T?=?4.2 К). Two types of pairwise impurity centers were formed at admixture concentrations of more than 1?wt%. Polarization of absorption bands was detected; these spectra were determined by resonance interactions between molecules of the impurity center. Resonant splitting of electronic levels for the translationally nonequivalent molecules in the unit cell of the naphthalene crystal was analyzed for the case, when one molecule was in the similar phase with the incident light wave and the other one was in antiphase.     

Synthesis of azachromones and azachromanones

Chemistry of Heterocyclic Compounds - This minireview highlights known methods for the synthesis of azachromones and azachromanones, including the earliest and the latest examples of their...     

Monodisperse magnetic poly(glycidyl methacrylate) microspheres for isolation of autoantibodies with affinity for the 46 kDa form of unconventional Myo1C present in autoimmune patients

Monodisperse nonmagnetic macroporous poly(glycidyl methacrylate) (PGMA) microspheres were synthesized by multistep swelling polymerization of glycidyl methacrylate, ethylene dimethacrylate and 2-[(methoxycarbonyl)methoxy]ethyl methacrylate (MCMEMA). This was followed (a) by ammonolysis to modify the microspheres with amino groups, and (b) by incorporation of iron oxide (γ-Fe₂O₃) into the pores to render the particles magnetic. The resulting porous and magnetic microspheres were characterized by scanning and transmission electron microscopy (SEM and TEM), atomic absorption and Fourier transform infrared spectroscopy (AAS and FTIR), elemental analysis, vibrating magnetometry, mercury porosimetry and Brunauer-Emmett-Teller adsorption/desorption isotherms. The microspheres are meso- and macroporous, typically 5 μm in diameter, contain 0.9 mM · g^?1 of amino groups and 14 wt.% of iron according to elemental analysis and AAS, respectively. The particles were conjugated to p46/Myo1C protein, a potential biomarker of autoimmune diseases, to isolate specific autoantibodies in the blood of patients suffering from multiple sclerosis (MS). The p46/Myo1C loaded microspheres are shown to enable the preconcentration of minute quantities of specific immunoglobulins prior to their quantification via SDS-PAGE. The immunoglobulin M (IgM) with affinity to Myo1C was detected in MS patients.

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Graphical abstract Monodisperse magnetic poly(glycidyl methacrylate) microspheres were synthesized, conjugated with 46 kDa form of unconventional Myo1C protein (p46/Myo1C) via carbodiimide (DIC) chemistry, and specific autoantibodies isolated from blood of multiple sclerosis (MS) patients; immunoglobulin M (IgM) level increased in MS patients.

     

Regioselective synthesis of 4-aryl-3,4-dihydro-1,3,5-triazino[2,1-a]isoindol-2-ones

The condensation of binucleophilic 3-amino-1-arylimino-1H-isoindoles with bifunctional 1-chloro-benzylisocyanates occurs regioselectively resulting in 3,4-dihydro-1,3,5-triazino[2,1-a]isoindol-2-one derivatives. The structures of the synthesized compounds were unambiguously established by NOE experiments.