Energy distributions and properties of the occupied and empty electronic states for a planar complex of nickel porphyrin NiP are studied by X-ray photoemission and absorption spectroscopy techniques. ...As a result of the analysis of the experimental spectra of valence photoemission, the nature and energy positions of the highest occupied electronic states were determined: the highest occupied state is formed mostly by atomic states of the porphine ligand; the following two states are associated with 3
d
states of the nickel atom. It was found that the lowest empty state is specific and is described by the σ-type
b
1
g
MO formed by empty
N
i
3
d
x
2
−
y
2
-states and occupied 2
p
-states of lone electron pairs of nitrogen atoms. This specific nature of the lowest empty state is a consequence of the donor–acceptor chemical bond in NiP.
This article discusses the mechanism studies of the functional provisions of the building construction, and identification of symptoms, in the case of which it's possible to forecast the appearance ...of accidents. The main purpose of this work is to find what kind of next examination should be performed otherwise, what sign that affects better than the others on the breakdown of the construction, you need to find to prevent its collapse and have time to take preventive measures to restore. In the work developed methods to determine the correct symptom, affecting more than any other on the disruption of the structure. An algorithm for the control of the system has been determined, Algorithm of monitoring when the life cycle of construction is maximum. It is proved that the issue of monitoring the priority or determination of the sign influencing the building breakdown can be defined by methods of nonlinear programming (parametric optimization). An algorithm which searches the main technical position of construction when the risk of disruption of the structure is minimal is developed.
The paper examines the problems faced by lecturers of the Department of Russian and Foreign Languages (Russian State Agrarian University-Moscow Timiryzev Agricultural Academy) when switching to ...distance learning due to the coronavirus pandemic. The authors dwell on specific features of the distance presentation of new material, as well as the control of learning outcomes. The experimental part presents the survey results of students' opinion on the frequency of using certain types of learning activities and the approval rating of learning activities from students' point of view. The authors also share their successful experience of teaching "Business Foreign Language" in a distance format for correspondence students. In conclusion, they summarize ideas on further ways to improve the effectiveness of distance courses of a foreign language for specific purposes.
•A novel photonic nanojet-based sensor system has been developed.•This system is an array of Al2O3 microspheres covered with a polymer layer impregnated with a sensitive probe.•When illuminated, the ...microstructure generates photonic nanojets that efficiently excite the sensitive layer.•Excitation of the sensitive layer via photonic nanojets provides 4-fold better sensing performance.•The demonstrated sensor system concept is customizable and can be modified to cover many non-trivial detection tasks.
A photonic nanojet phenomenon that is strong electromagnetic field local enhancement is widely used for various optical tasks like surface-enhanced Raman scattering or surface-enhanced fluorescence. Here we present a novel implementation of this effect for boosting the sensory response of the fluorescent optical probe through its more efficient pumping via photonic nanojets. For this, a sensitive layer consisting of chitosan polymer impregnated with a fluorescent probe designed for the selective determination of Au3+ ions was deposited onto the surface of an array of dielectric alumina microspheres. The photonic nanojet effect was numerically predicted and experimentally observed in the developed system. It was demonstrated that the change in the refractive index of the matrix caused by polymer swelling has a significant effect on the characteristics of the sensor. Under certain conditions, such as the diameter of the microspheres and the contrast of the refractive index a four-fold decrease in the detection limit of the chemosensor was achieved.
The form factor of a hollow electron beam for transition radiation has been calculated. It has been shown that the characteristics of coherent radiation are significantly different for conventional ...solid and hollow beams. Numerical estimates have been obtained for terahertz radiation frequencies and relativistic energies of el-ectrons.
In the theory of radiation emitted by bunches of charged particles, the effects of coherence are commonly taken into account by multiplying the intensity of radiation generated by a single particle ...by the form factor of the bunch, which depends on its size, shape, and particle distribution. Here, it is demonstrated that this approach is, generally speaking, incorrect for polarization radiation from a wide class of structures like photonic crystals and metasurfaces. The theory of coherent Smith–Purcell radiation from such structures has been developed. It is shown that the commonly accepted approach is applicable only under two conditions: (i) the observation point lies in the plane containing the trajectory of the bunch and the normal to the surface of the target, and (ii) the radius of the bunch is much smaller than the effective range of the Coulomb field of the moving electrons.
Ten tris(2-hydroxyethyl)ammonium (triethanolammonium)-based protic ionic liquids (ILs) and one molten salt were synthesized by proton transfer reaction from sulfonic acid to triethanolamine (TEOA). ...The produced PILs were dried under high vacuum at 50°C for 8h before use. The PILs were characterized by 1H NMR, 13C NMR, 1H/15N NMR and FT-IR spectroscopic methods. The parameters of IR and NMR spectra of the studied PILs were determined by the nature of the substituent on the sulfonic acid benzene ring. The phase behavior of the PILs was studied using differential scanning calorimetry (DSC) and thermogravimetric analyses (TGA). The temperature dependence of the conductivity and the electrochemical window of each PIL was investigated. The substitution effect on the PILs anionic component was discussed for the studied properties.
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•Protic ionic liquids based on triethanolamine with sulfonic acids were synthesized.•The PILs were characterized by NMR and FT-IR spectroscopic methods.•The phase behavior of the PILs using DSC and TGA was studied.•The conductivity of salts are within the range of 10−5÷10−3Ω−1·cm−1.•The electrochemical window of PILs at 120°С lies within the range of 2.9–4.5V.
The safety of micro- and nanoparticle sorbents based on zero-valent iron and their detoxifying activity in peat eutrophic soil (Eutric Histosol) polluted by the emissions of a copper-nickel (Cu/Ni) ...plant in the Kola Peninsula are studied. Both iron nanoparticles and microparticles at a dose of 2% have emerged to be nontoxic according to the results of three standard bioassays based on the response of test organisms of different taxonomic affiliations. The toxicity is assessed according to the change in the root length of
Sinapis alba
L. seedlings in uncontaminated peat as well as the survival rate of the crustacean
Ceriodaphnia affinis
Lilljeborg and the protozoan
Paramecium caudatum
Ehrenberg in water extracts obtained of samples. Iron-containing preparations in a statistically significant manner reduce the ecotoxicity of soil caused by an extremely high content of copper (6877 mg/kg) and nickel (2580 mg/kg). The tested preparations differ in their remediation capacity. Soil phytotesting demonstrates that iron nanoparticles significantly outperform the detoxifying effect of microparticles (iron powder). However, analysis of water extracts does not show any advantage of nanoparticles in reducing the soil toxicity. The dependence of the assessed detoxifying capacity of zero-valent iron nanoparticles on soil properties and the plant species used in phytotesting is discussed. The phytoeffect of nanoparticles in standard
S. alba
tests is 1.5-fold higher as compared with iron microparticles (root length of 117 ± 4.3 and 80 ± 7.6 mm, respectively). However, the chronic phytotoxicity assessment of the same soils using perennial ryegrass
Lolium perenne
L. fails to find any differences between the effects of micro- and nanoparticles of zero-valent iron.
In this work, we construct for the first time the theory of small-angle transition radiation from multilayered structures. The theoretically obtained spectral and angular distributions of radiated ...photons are compared with those predicted by Geant4, a very popular package used today for numerical simulation of different physical processes. We demonstrate that, while spectral distributions ideally coincide, the angular ones differ. We argue that transition radiation from the multilayered structure must contain sharp spikes having the interference nature and caused by the effect of merging two maximum frequencies in dispersive media, and thus Geant4 needs improving in this respect. The transition radiation theory developed here for the small-angle case can play a vital part for the possible future Small Angle Spectrometer at the LHC, other experiments of this kind, and detectors for hadrons of the tera-electron-volt energy range.
Bioceramics are used to treat bone defects but in general do not induce formation of new bone, which is essential for regeneration process. Many aspects related to bioceramics synthesis, properties ...and biological response that are still unknown and, there is a great need for further development. In the most recent research efforts were aimed on creation of materials from biological precursors of apatite formation in humans. One possible precursor is octacalcium phosphate (OCP), which is believed to not only exhibit osteoconductivity but possess osteoinductive quality, the ability to induce bone formation. Here we propose a relatively simple route for OCP ceramics preparation with a specifically designed microstructure. Comprehensive study for OCP ceramics including biodegradation, osteogenic properties in ortopic and heterotopic models and limited clinical trials were performed that demonstrated enhanced biological behavior. Our results provide a possible new concept for the clinical applications of OCP ceramics.
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