108 research outputs found
Spin ladder compound Pb(0.55)Cd(0.45)V(2)O(5): synthesis and investigation
The complex oxide Pb(0.55)Cd(0.45)V(2)O(5) was synthesized and investigated
by means of X-ray powder diffraction, electron diffraction, magnetic
susceptibility measurements and band structure calculations. Its structure is
similar to that of MV(2)O(5) compounds (M = Na, Ca) giving rise to a spin
system of coupled S=1/2 two-leg ladders. Magnetic susceptibility measurements
reveal a spin gap-like behavior with \Delta ~ 270 K and a spin singlet ground
state. Band structure calculations suggest Pb(0.55)Cd(0.45)V(2)O(5) to be a
system of weakly coupled dimers in perfect agreement with the experimental
data. Pb(0.55)Cd(0.45)V(2)O(5) provides an example of the modification of the
spin system in layered vanadium oxides by cation substitution. Simple
correlations between the cation size, geometrical parameters and exchange
integrals for the MV(2)O(5)-type oxides are established and discussed.Comment: 8 pages, 7 figure
Frustrated spin-1/2 square lattice in the layered perovskite PbVO(3)
We report on the magnetic properties of the layered perovskite PbVO(3). The
results of magnetic susceptibility and specific heat measurements as well as
band structure calculations consistently suggest that the S=1/2 square lattice
of vanadium atoms in PbVO(3) is strongly frustrated due to
next-nearest-neighbor antiferromagnetic interactions. The ratio of
next-nearest-neighbor (J(2)) to nearest-neighbor (J(1)) exchange integrals is
estimated to be J(2)/J(1)\approx 0.2-0.4. Thus, PbVO(3) is within or close to
the critical region of the J(1)-J(2) frustrated square lattice. Supporting
this, no sign of long-range magnetic ordering was found down to 1.8 K.Comment: 4 pages, 4 figures, 2 table
Localization of the E. coli Dps protein molecules in a silicon wires under removal of residual salt
The work is related to the removal of residual salts in hybrid structures formed as a result of silicon wires arrays combining with a nanomaterial of natural origin – bacterial ferritin-like protein Dps. The study of the morphology and composition of the surface and the bulk part of the hybrid structure as a result of combination and subsequent washing in water was carried out.
The method of metal-assisted wet chemical etching was used to obtain silicon wires arrays. To obtain recombinant protein, Escherichia coli BL21*(DE3) cells with chromatographic purification were used as producers. The combination of silicon wires with protein molecules was carried out by layering them in laboratory conditions, followed by drying. The residual salt found earlier in the hybrid material was removed by washing in water. The resulting hybrid material was studied by scanning electron microscopy and X-ray photoelectron spectroscopy. A well-proven complementary combination of scanning electron microscopy and X-ray photoelectron spectroscopy together with ion etching was used to study the morphology of the hybrid material “silicon wires – bacterial protein Dps” and the composition with physico-chemical state respectively.
In arrays of silicon wires with a wire diameter of about 100 nm and a distance between them from submicron to nanometer sizes, protein was found as a result of layering and after treatment in water. At the same time, the amount of residual NaCl salt is minimized on the surface of the hybrid structure and in its volume.
The obtained data can be used in the development of coating technology for the silicon wires developed surface available for functionalization with controlled delivery of biohybrid materia
Mass Appraisal of Residential Apartments: An Application of Random Forest for Valuation and a CART-Based Approach for Model Diagnostics
Crystal structure and properties of the new complex vanadium oxide <tex>K_{2}SrV_{3}O_{9}$</tex>
Advanced electron microscopy and its possibilities to solve complex structures: application to transition metal oxides
Cover Feature: Extended Limits of Reversible Electrochemical Lithiation of Crystalline V 2
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