Electrical properties of ZnO:Al thin films fabricated by pulsed laser deposition method

The possibility of the high quality AZO thin films fabrication by the PLD method using the second harmonic of the Q-switched YAG:Nd3+ laser is demonstrated. The investigations of dependence of the AZO thin films properties on the PLD conditions (concentration of Al in the target, buffer gas pressure) have been conducted. The optimum conditions of the ZnO:Al thin films deposition have been defined

Application of laser texturing method for mc-Si solar cells fabrication

The results of the experiments on the “black” mc-Si surface fabrication by the nanosecond pulses of the YAG laser second harmonic and on application of the introduced laser texturing method for the mc-Si solar cells efficiency improvement are represented. The developed version of laser texturing permits producing a low-reflection mc-Si surface with the reflectance of ~3% in the spectral range of 0.3-1.1 μm. The application of the introduced laser texturing method in mc-Si solar cells fabrication makes it possible to increase the short circuit current density and quantum efficiency

First-principles quantum transport modeling of thermoelectricity in single-molecule nanojunctions with graphene nanoribbon electrodes

We overview nonequilibrium Green function combined with density functional theory (NEGF-DFT) modeling of independent electron and phonon transport in nanojunctions with applications focused on a new class of thermoelectric devices where a single molecule is attached to two metallic zigzag graphene nanoribbons (ZGNRs) via highly transparent contacts. Such contacts make possible injection of evanescent wavefunctions from ZGNRs, so that their overlap within the molecular region generates a peak in the electronic transmission. Additionally, the spatial symmetry properties of the transverse propagating states in the ZGNR electrodes suppress hole-like contributions to the thermopower. Thus optimized thermopower, together with diminished phonon conductance through a ZGNR/molecule/ZGNR inhomogeneous structure, yields the thermoelectric figure of merit ZT~0.5 at room temperature and 0.5<ZT<2.5 below liquid nitrogen temperature. The reliance on evanescent mode transport and symmetry of propagating states in the electrodes makes the electronic-transport-determined power factor in this class of devices largely insensitive to the type of sufficiently short conjugated organic molecule, which we demonstrate by showing that both 18-annulene and C10 molecule sandwiched by the two ZGNR electrodes yield similar thermopower. Thus, one can search for molecules that will further reduce the phonon thermal conductance (in the denominator of ZT) while keeping the electronic power factor (in the nominator of ZT) optimized. We also show how often employed Brenner empirical interatomic potential for hydrocarbon systems fails to describe phonon transport in our single-molecule nanojunctions when contrasted with first-principles results obtained via NEGF-DFT methodology.Comment: 20 pages, 6 figures; mini-review article prepared for the special issue of the Journal of Computational Electronics on "Simulation of Thermal, Thermoelectric, and Electrothermal Phenomena in Nanostructures", edited by I. Knezevic and Z. Aksamij

Interaction-induced structural transformation of lysozyme and kappa-carrageenan in binary complexes

The interactions between κ-carrageenan and hen egg-white lysozyme have been studied. In dilute solutions, the insoluble complexes with constant κ-carrageenan/lysozyme ratio of 0.3, or 12 disaccharide units per mole of protein are formed. FTIR-spectroscopy revealed that κ-carrageenan retains its unordered conformation and induces the rise of β-structure in lysozyme. In the complexes formed in concentrated mixtures, κ-carrageenan adopts helical conformation and lysozyme retains its native-like structure. These complexes contain 21 disaccharide units per mole of protein. Molecular modeling showed that flexible coil and rigid double helix of κ-carrageenan have different binding patterns to lysozyme surface. The latter has a strong preference to positively charged spots in lysozyme α-domain while the former also interacts to protein β-domain and stabilizes short-living β-structures. The obtained results confirm the preference of unordered κ-carrageenan to β-structure rich protein regions, which can be further used in the development of carrageenan-based protection of amyloid-like aggregation of proteins

Interaction of bovine serum albumin with cationic imidazolium-containing amphiphiles bearing urethane fragment: Effect of hydrophobic tail length

© 2020 Complexation ability of homologous series of amphiphiles bearing imidazolium and urethane moieties (IAC-n, n = 14, 16, 18) toward bovine serum albumin (BSA) has been investigated by various physico-chemical methods (tensiometry, fluorescence spectroscopy, spectrophotometry, dynamic and electrophoretic light scattering, circular dichroism, and transmission electron microscopy). It has been revealed, that aggregation thresholds of systems based on IAC-n could be 5–8-fold reduced by BSA addition. Fluorescent analysis allows to estimate that binding of components is favorably mediated by tryptophan amino acid residues and is driven by different forces depending on the length of amphiphile hydrophobic tail. In particular, dominate contribution of Van der Waals interactions to the complexation has been shown in the case of IAC-14 and IAC-16, while hydrophobic interactions prevailed for IAC-18. It has been demonstrated that amphiphile addition causes reversible unfolding of protein macromolecules in all cases. Spectrophotometry assay exhibits that amphiphile/BSA complexes have more significant solubilization capacity toward hydrophobic guest in comparison with individual IAC-n systems

Structure of a shell made from uranium alloyed with iron and germanium after explosive loading

This paper presents results of metallographic examination of a thick-wall spherical shell from uranium alloyed with iron and germanium. This shell is recovered after low-level explosive loading. Light microscopy, hardness measurement, scanning electron microscopy and X-Ray diffraction study were used to investigate the meridional section of the test shell as this section most completely exhibits the whole variety of structural features associated with explosive loading of the material. Processing, presentation, and analysis of experimental data on volumetric distribution of studied physical quantities were performed with the help of digital panning and color mapping

Pillar[5]arenes as potential personage for DNA compactization and gene therapy

© 2020 Elsevier B.V. Here we demonstrated that pillar[5]arenes with counterions I− and Cl− show the ability to plasmid compactization and increasing bacterial transformation efficiently. Pillar[5]arenes have been tested for binding with palindromic decamer oligonucleotide and interacting with plasmid DNA. The complexation of pillar[5]arene with oligonucleotide has been shown by NMR- and CD-spectroscopy. Pillar[5]arenes form complexes with oligonucleotide in solution in the 1:1 or 1:2 stoichiometry. Molecular modeling allowed to constructs the models of these complexes. Pillar[5]arene interaction with the plasmid DNA have been studied using atomic force microscopy. According to AFM images pillar[5]arene-I− and pillar[5]arene-Cl− packed up the plasmid DNA to aggregates with diameter about 100 nm with different morphology. An increase in DNA transformation efficiency into bacterial cells has been shown for pillar[5]arenes with counterions I− and Cl−

Investigation of neutron emissions from D(d,n)3^{3}He and T(d,n)4^{4} He reactions in a 10 TW picosecond laser facility SOKOL-P

Experimental results on fast neutron generation in D(d,n)$^{3}$He and T(d,n)$^{4}$He reactions in the SOKOL-P laser facility [1] are presented. Solid targets were irradiated by 1.054 ${\rm \mu}$m, s- or p-polarized laser pulses of energy 5-8 J on target and duration 0.85-2 ps. The peak laser intensity was 0.5-2$\cdot$10$^{18}$ W/cm$^{2}$. Flat deuterated plastic (CD$_{2})_{\rm n}$ targets and Ti D$_{\rm \alpha }$T$_{\rm \beta}$ targets were used in experiments. Some experiments were carried out with additional targets placed in front of and behind the laser target. The used (TOF) time-of-flight technique helped identify neutrons from D(d,n)$^{3}$He and T(d,n)$^{4}$He reactions. Yields up to 10$^{6 }$ DD-neutrons and 10$^{7}$ DT-neutrons were measured. Interaction of the fast ion beam with the target can explain the observed yield