364 research outputs found
The effect of the complex processing of Microalgae Chlorella vulgaris on the intensification of the lipid extraction process
Microalgae are considered a promising source of lipids. However, the existing technologies of their extraction necessitate a massive improvement. In the course of the study optimal parameters of microwave radiation and of enzyme mixture "Cellolux A" and "Protosubtilin G3x" were experimentally selected and theoretically proved so as to allow increasing the yield of lipids 5.75 times to 23 % in comparison with the control sample (5 %). Moreover, the ratio and type of polar and non-polar solvents in the extraction stage for the maximum extraction of lipids was determined taking into account the necessity to process protein-lipid complexes
Spin splitting of surface states in HgTe quantum wells
We report on beating appearance in Shubnikov-de Haas oscillations in
conduction band of 18-22nm HgTe quantum wells under applied top-gate voltage.
Analysis of the beatings reveals two electron concentrations at the Fermi level
arising due to Rashba-like spin splitting of the first conduction subband H1.
The difference dN_s in two concentrations as a function of the gate voltage is
qualitatively explained by a proposed toy electrostatic model involving the
surface states localized at quantum well interfaces. Experimental values of
dN_s are also in a good quantitative agreement with self-consistent
calculations of Poisson and Schrodinger equations with eight-band kp
Hamiltonian. Our results clearly demonstrate that the large spin splitting of
the first conduction subband is caused by surface nature of states
hybridized with the heavy-hole band.Comment: 7 pages, 7 figure
Spin Polarization Phenomena and Pseudospin Quantum Hall Ferromagnetism in the HgTe Quantum Well
The parallel field of a full spin polarization of the electron gas in a
\Gamma8 conduction band of the HgTe quantum well was obtained from the
magnetoresistance by three different ways in a zero and quasi-classical range
of perpendicular field component Bper. In the quantum Hall range of Bper the
spin polarization manifests in anticrossings of magnetic levels, which were
found to strongly nonmonotonously depend on Bper.Comment: to be published in AIP Conf. Proc.: 15-th International Conference on
Narrow Gap Systems (NGS-15
Transport properties of a 3D topological insulator based on a strained high mobility HgTe film
We investigated the magnetotransport properties of strained, 80nm thick HgTe
layers featuring a high mobility of mu =4x10^5 cm^2/Vs. By means of a top gate
the Fermi-energy is tuned from the valence band through the Dirac type surface
states into the conduction band. Magnetotransport measurements allow to
disentangle the different contributions of conduction band electrons, holes and
Dirac electrons to the conductivity. The results are are in line with previous
claims that strained HgTe is a topological insulator with a bulk gap of ~15meV
and gapless surface states.Comment: 11 pages (4 pages of main text, 6 pages of supplemental materials), 8
figure
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