9 research outputs found
Rashba Spin Splitting in HgCdTe Quantum Wells with Inverted and Normal Band Structures
In quantum wells (QWs) formed in HgCdTe/CdHgTe heterosystems with a variable composition of Cd(Hg), Shubnikov-de-Haas (SdH) oscillations are investigated to characterize the Rashba-type spin-orbit coupling in QWs with both a normal and inverted band structure. Several methods of extracting the Rashba spin-splitting at zero magnetic field and their magnetic field dependences from the beatings of SdH oscillations are used for greater reliability. The large and similar Rashba splitting (25–27 meV) is found for different kinds of spectrum, explained by a significant fraction of the p-type wave functions, in both the E1 subband of the sample with a normal spectrum and the H1 subband for the sample with an inverted one
Application of cold plasma to control the microbiota composition on the surface of potato tubers
A study of the effect of low-temperature plasma on potato tubers was carried out. A comparative assessment of changes in the rate of germination, the size of shoots and the mass of shoots was carried out. Changes in the number of bacteria and fungi on the surface of tubers were analysed for different durations of exposure. It was found that growth characteristics did not change. The number of bacteria on the surface of tubers was significantly reduced due to the exposure to low-temperature plasma
The microstructural and optical properties of Ge/Si heterostructures grown by low-temperature molecular beam epitaxy
XANES Measurements for Studies of Adsorbed Protein Layers at Liquid Interfaces
X-ray absorption near edge structure (XANES) spectra for protein layers adsorbed at liquid interfaces in a Langmuir trough have been recorded for the first time. We studied the parkin protein (so-called E3 ubiquitin ligase), which plays an important role in pathogenesis of Parkinson disease. Parkin contains eight Zn binding sites, consisting of cysteine and histidine residues in a tetracoordinated geometry. Zn K-edge XANES spectra were collected in the following two series: under mild radiation condition of measurements (short exposition time) and with high X-ray radiation load. XANES fingerprint analysis was applied to obtain information on ligand environments around zinc ions. Two types of zinc coordination geometry were identified depending on X-ray radiation load. We found that, under mild conditions, local zinc environment in our parkin preparations was very similar to that identified in hemoglobin, treated with a solution of ZnCl2 salt. Under high X-ray radiation load, considerable changes in the zinc site structure were observed; local zinc environment appeared to be almost identical to that defined in Zn-containing enzyme alkaline phosphatase. The formation of a similar metal site in unrelated protein molecules, observed in our experiments, highlights the significance of metal binding templates as essential structural modules in protein macromolecules
Scaling in the Quantum Hall Regime for a Double Quantum Well Nanostructure in High Magnetic Field
Infrared Emitting PbS Nanocrystal Solids through Matrix Encapsulation
Colloidal
semiconductor nanocrystals (NCs) are emerging as promising
infrared-emitting materials, which exhibit spectrally tunable fluorescence,
and offer the ease of thin-film solution processing. Presently, an
important challenge facing the development of nanocrystal infrared
emitters concerns the fact that both the emission quantum yield and
the stability of colloidal nanoparticles become compromised when nanoparticle
solutions are processed into solids. Here, we address this issue by
developing an assembly technique that encapsulates infrared-emitting
PbS NCs into crystalline CdS matrices, designed to preserve NC emission
characteristics upon film processing. An important feature of the
reported approach is the heteroepitaxial passivation of nanocrystal
surfaces with a CdS semiconductor, which shields nanoparticles from
the external environment leading to a superior thermal and chemical
stability. Here, the morphology of these matrices was designed to
suppress the nonradiative carrier decay, whereby increasing the exciton
lifetime up to 1 μs, and boosting the emission quantum yield
to an unprecedented 3.7% for inorganically encapsulated PbS NC solids