Comparative analysis of journals on social sciences and humanities in Ukraine and the world

Summary This article analyses the changes in development of journals on social sciences and humanities in Ukraine and shows the results of the comparative analysis of journals on social sciences and humanities in Ukraine, and journals in the world included in relevant databases of the US Institute for Scientific Information (Philadelphia).     

Solvent-free derivatization of pristine multi-walled carbon nanotubes with dithiols

We report on direct solvent-free derivatization of pristine multi-walled carbon nanotubes (MWNTs) with aliphatic dithiols (1,4-butanedithiol, 1,6-hexanedithiol and 1,8-octanedithiol), by means of heating at 130–150 °C under reduced pressure. This method requires no additional chemical activation and about 2 h only for completion. Studies by high-resolution transmission electron microscopy and scanning electron microscopy with energy dispersive X-ray spectroscopy showed that dithiol-derivatized MWNTs have a high affinity to ZnCl₂ in solution, which covers the nanotubes with a dense amorphous layer. According to PM3 semi-empirical calculations, employing a closed-cap zigzag (10,0) single-walled carbon nanotube (SWNT) model incorporating a Stone-Wales defect, site-specificity of the addition depends on the mutual position of pentagons. If the nanotube contains pyracylene units or Stone-Wales defect, the addition takes place on their 6,6 or 7,7 bonds, respectively, whereas for isolated pentagons, preferential reaction sites are their C–C bonds. Ideal graphene sheet sidewalls with cylindrical curvature are relatively inert (although one cannot discard the possibility to activate the reaction by heating). Dithiol groups introduced in the way proposed can be used as chemical linkers for anchoring metal complexes and nanoparticles to carbon nanotubes, attaching SWNTs to gold tips for atomic force and scanning tunneling microscopy, and potentially for adsorption and concentration of trace metal ions.     

Synthetic and bio-hybrid nanoscale layers with tailored surface functionalities

We examine the prospective routes for the design of synthetic/biomacromolecular/inorganic film assemblies for photothermal cell based on biomimetic approach. We demonstrate examples of channel proteins immobilized onto surfaces of silicon single crystals modified with Langmuir–Blodgett and self-assembled monolayers. These proteins can be immobilized in intact, closed-pore conformation. Their state within photosensitive monolayers can be controlled by the photoisomerization reaction triggered by UV light.     

Interaction between non-parallel dislocations in piezoelectrics

The total interaction force F¹² between two crossing (non-intersecting) straight dislocations is found and analyzed for the three types of piezoelectric media of unrestricted anisotropy: an unbounded body, an infinite plate and a half-infinite body. In the latter two cases the dislocations are supposed to be parallel with the surfaces, which are in turn implied to be mechanically free of tractions and electrically closed (metalized). The found force F¹² is orthogonal to the parallel planes, P and Q, containing the crossing dislocations. In an unbounded medium the value F¹² proves to be independent of the distance between P and Q. On the other hand, it depends on directions of the dislocations and on their Burgers vectors: the force F¹² may be either attractive or repulsive. In a plate the interaction becomes sensitive to dislocation positions y^(1,2) with respect to the surfaces. Only in the situations, when dislocations are much closer to each other than to the both surfaces, their interaction may be approximately described by the solution for an unbounded medium. Otherwise, corrections arising from the image forces due to the plate surfaces become essential. The dislocation in the vicinity of a surface strongly acts on its counterpart only until the latter situates even closer to the same surface than the first one. When the second dislocation leaves this narrow zone, the interaction force on it abruptly decreases to a very small level. With an increase in the thickness of the plate, this behavior becomes more and more pronounced. In a half-infinite medium the interaction between the dislocations is exactly described by a Heaviside step-like dependence F¹²∝H(y⁽¹⁾-y⁽²⁾) valid for any y^(1,2). It is shown that we deal here with an analog of the plane capacitor effect.     

Emission spectra of lanthanide ions in hexafluoroelpasolite lattices excited by synchrotron radiation

Emission spectra at 10 K employing synchrotron radiation have been recorded for the tripositive lanthanide ions, Ln = Sm, Gd, Tb, Ho, and Er situated at octahedral (or nearly octahedral) site symmetry in hexafluoroelpasolite Cs₂NaMF₆ (M = Y, Sc, or Ga) lattices. Interconfigurational 5d → 4f transitions are only observed for Er³⁺, and the intensity ratio of 4f¹⁰5d → 4f¹¹ emission, compared with 4f¹¹ → 4f¹¹ emission, with excitation into 5d levels, is greater for M = Ga than M = Sc. The highest energy intraconfigurational emission is from ⁴G_5/2 (Sm³⁺), ⁶P_7/2 (Gd³⁺), ⁵D₃ (Tb³⁺), ⁵G₄ (Ho³⁺), and ²F(2)_7/2 (Er³⁺). Detailed energy level assignments have been given for Ln = Sm, Gd, and the remaining spectra are assigned as multiplet–multiplet transitions.     

Indexing schemes for similarity search in datasets of short protein fragments

We propose a family of very efficient hierarchical indexing schemes for ungapped, score matrix-based similarity search in large datasets of short (4–12 amino acid) protein fragments. This type of similarity search has importance in both providing a building block to more complex algorithms and for possible use in direct biological investigations where datasets are of the order of 60 million objects. Our scheme is based on the internal geometry of the amino acid alphabet and performs exceptionally well, for example outputting 100 nearest neighbours to any possible fragment of length 10 after scanning on average less than 1% of the entire dataset.     

Ferroelectric liquid crystal aligned on SiO2 thin films using ion‐beam deposition

Abstract— Results for a ferroelectric‐liquid‐crystal (FLC) display cell, aligned on inorganic SiO₂ thin‐film surfaces by using oblique ion‐beam sputtering deposition on the substrates, is presented. A large deposition angle from 60° to 80° can be employed for the thin alignment layer, with thicknesses varying from 5 to 40 nm. Two types of uniform alignment, chevron (before electrical treatment) and quazi‐bookshelf (after electrical treatment), were studied. High‐quality alignment on large‐sized substrates was also easily be achieved because of the linear design of the ion‐beam sputtering source, which was previously a significant challenge for FLC on SiO_x layers.     

Robust DFT-based filtering of pulse-like FM signals corrupted by impulsive noise

Filtering of pulse-like FM signals with varying amplitude corrupted by impulse noise is considered. The robust DFT calculated for overlapped intervals is used for this aim. This technique is proposed in order to decrease amplitude distortion of output signals that can be introduced by the robust DFT calculated within a wide interval including possible zero-output. The proposed algorithm is realized through the following steps. In the first stage, the robust DFT is calculated for the intervals. Filtered signals from the intervals are obtained by applying the standard inverse DFT for the robust DFTs applied to input data. In the second stage, results for different overlapped intervals are combined using the appropriate order statistics. In addition, an algorithm inspired by the intersection of the confidence intervals rule is used for adaptive selection of the interval width in the robust DFT. Algorithm accuracy is tested on numerical examples. Computational complexity analysis is also provided.     

X-ray photoelectron spectroscopy study of the initial growth of transition metal nanoscale films on (100) Si substrates

The initial growth stages of materials non-active to a substrate has been extensively studied for decades, whereas there had been fewer studies on the initial growth of active metals on silicon substrate, despite its technological importance. In this paper the very early growth stages of transition metal (Ti, V and Nb) films deposited by rf sputtering on unheated (100) Si substrate were studied by in situ X-ray photoelectron spectroscopy. The following sequence of the phase composition and the growth mechanism changes during deposition process was revealed. Initially in a submonolayer regime, small 3D TiO₂ islands are formed via reduction of a native silicon oxide layer on a substrate followed by formation of a TiO phase between TiO₂ islands and on their top. After deposition of ca. 2 monolayers a metallic Ti phase appears and later only the metal Ti film grows. The same growth behavior takes place at Nb and V deposition with a difference that in the case of Nb the above changes occur at earlier stages what can be explained by the highest niobium activity to the reduction of silicon oxide in the row V, Nb, Ti.     

Viscoelastic nanoscale properties of cuticle contribute to the high-pass properties of spider vibration receptor (Cupiennius salei Keys).

Atomic force microscopy (AFM) and surface force spectroscopy were applied in live spiders to their joint pad material located distal of the metatarsal lyriform organs, which are highly sensitive vibration sensors. The surface topography of the material is sufficiently smooth to probe the local nanomechanical properties with nanometre elastic deflections. Nanoscale loads were applied in the proximad direction on the distal joint region simulating the natural stimulus situation. The force curves obtained indicate the presence of a soft, liquid-like epicuticular layer (20-40 nm thick) above the pad material, which has much higher stiffness. The Young modulus of the pad material is close to 15 MPa at low frequencies, but increases rapidly with increasing frequencies approximately above 30 Hz to approximately 70 MPa at 112 Hz. The adhesive forces drop sharply by about 40% in the same frequency range. The strong frequency dependence of the elastic modulus indicates the viscoelastic nature of the pad material, its glass transition temperature being close to room temperature (25 +/- 2 degrees C) and, therefore, to its maximized energy absorption from low-frequency mechanical stimuli. These viscoelastic properties of the cuticular pad are suggested to be at least partly responsible for the high-pass characteristics of the vibration sensor's physiological properties demonstrated earlier.