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Abstract The effect of structure of 25 aromatic compounds on the morphology of carbon formed from them during heating to a temperature of 970°C in an inert atmosphere is studied. The specific surface area is determined for a number of products via nitrogen adsorption (28–48 m2/g). Several aromatic compounds are shown to form carbon without melting stage. X-ray phase analysis nevertheless confirms the formation of just amorphous carbon in all cases, and a negligible amount of graphite in amorphous carbon in only two cases. The thermolysis of a number of compounds is studied via synchronous thermal analysis. It is shown that slow heating during thermolysis can reduce the temperatures of transformation by tens of degrees and even alter the nature of thermolysis.

Two versions of a forward hodoscope have been developed and manufactured based on scintillation and radiation-resistant quartz plates. The hodoscopes are designed to register ions in the BM @ N experiment at the NICA accelerator complex. The light outputs and their inhomogeneity were measured as a function of the coordinates of the passage of particles through the hodoscope plates on the calibration beam of the secondary electrons of the “Pakhra” synchrotron of the Lebedev Physical Institute.

Designs of hodoscopes of nuclear fragments based on quartz and scintillation plates with light pickup by silicon avalanche photodiodes are described. Hodoscopes are planned for use in the BM@N experiment for registration of heavy nuclear fragments near the axis of the heavy ion beam. The results of measurements of light yields in detector elements based on quartz and scintillation plates on the electron beam of the synchrotron "Pakhra" (LPI) are presented. The measured nonuniformity of the light collection shows that readout from both sides of hodoscope detector elements is needed.

This review focuses on the processes involved in producing heat-resistant matrices for fiber reinforced plastics (FRP) by polymerization of the resins consisting of phthalonitrile monomers and comonomers, and the specifics of fiber reinforced plastics fabrication technologies. Polymerization behaviors observed in the presence of various types of initiators and in different temperature modes are reviewed. Fabrication methods and mechanical properties of FRPs based on phthalonitrile resins with various reinforcing materials are discussed. Properties of glass fiber reinforced plastics (GFRP) and carbon fiber reinforced plastics (CFRP) obtained through curing of different phthalonitriles are compared.

The results of studies of the structural, optical, photoluminescence, and photoelectric properties of the ZnO–LiNbO3 thin-film structure are reported. The results of X-ray structural analysis of a zinc-oxide film synthesized on a single-crystal lithium-niobate substrate and on a quartz glassy substrate are presented. The transmittance, reflectance, absorption, photoluminescence, and photocurrent spectra of the ZnO–LiNbO3 thin-film and ZnO–SiO2 structures in the ultraviolet and visible spectral regions are given.

The immobilization of the microalgae (MA) of cells on biosorbents based on polyethyleneimine and cellulose-containing plant components is studied. Polyethyleneimine-based polycationic polymers have a high level of affinity for the surface structures of the MA and ensure that the cells are strongly attached to the surface of the sorbent. The introduction of plant fillers in the composition of such polymers allows us to increase their biodegradation rate and reduce costs. In the present study, six insoluble porous polymeric materials obtained by the cryopolymerization of a mixture of polyethyleneimine and various plant components using diethylene glycol diglycidyl ether were synthesized. The lyophilized biomass of plant cell cultures of Ajuga turkestanica and Polyscias fruticosa, as well as the cell-structured material (CSM) obtained from their biomass, is used as a bio-filler. Studying the kinetics and evaluating the efficiency of the immobilization of cells of the model MA culture showed the high sorption ability of the obtained materials: after 24 h of cultivation, the efficiency of immobilization was 72–77%. Assessment of the level of the photosynthetic activity of the MA cells using the method of pulse-simulated fluorimetry demonstrated that the studied biosorbents did not have any toxic effect on the cells and did not affect their functional activity. Novel biosorbents can be effectively used to collect the biomass of microorganisms from natural aquatic environments and industrial cultivators.

We study the possibilities of defining some operations on fields via the remaining operations. In particular, we prove that multiplication on an arbitrary field can be defined via addition if and only if the field is a finite extension of its prime subfield. We give a sufficient condition for the nondefinability of addition via multiplication and demonstrate that multiplication and addition on the reals and complexes cannot be mutually defined by means of the relations with parameters which are preserved under automorphisms. We also describe the mutual definability of addition, multiplication, and exponentiation via the remaining two operations.

New porous polymer materials based on crosslinked highly branched polyethylenimine (PEI) are synthesized. Epichlorohydrin, diethylene glycol diglycidyl ether, and chloroacetic acid diesters with ethylene glycol, diethylene glycol, triethylene glycol, and polyethylene glycol-400 are used as crosslinking agents. The PEI/crosslinking agent ratio and means of polymerization, which substantially affect the water uptake of the products, are varied. It is shown that these materials exhibit high sorption activity with respect to metal cations that form complexes with amino groups of PEI: up to 172, 116, and 106 mg/g for copper(II), cobalt(II), and nickel(II), respectively, in an acetate buffer solution at a pH 5.

The evaporation and crystallization of a droplet and a thin layer of aqueous solutions of LiBr and LiCl salts on a heated wall with a temperature Tw = 86°C were studied experimentally. Crystallization curves were obtained for a wide range of initial salt concentrations. For the first time it was shown that for different C01 values the crystallization rates Jcr were different; the Jcr curve was nonlinear. With C01 decreasing, the supersaturation at the onset of crystallization increased, because of different induction times with respect to the generation of the first active crystallization center. It is known for relatively large crystals that heat transfer influences the rate of crystallization. Processing of the experimental data with due account of the basic thermophysical parameters shows that supersaturation also affects the crystal growth. The crystallization rate in a thin layer is significantly higher than in a droplet. It was found that description of crystallization in a droplet should take into account strong anisotropy of the crystallization.

We introduce and study the class of holographic models which can be defined by copying of some of its finite parts by means of automorphisms. We prove this class to differ from the class of countably categorical models. Characterizations of the classes of holographic Boolean algebras, abelian groups, linear orderings, fields, and equivalences are given.

The composition of dipterans inhabiting fieldfare nests in a big city was studied for the first time, based on material collected soon after chick fledging. Larvae of 21 species belonging to 14 families were found, including saprophages, necrophages, and predators (Scatopsidae, Ceratopogonidae, Phoridae, Chloropidae, Anthomyiidae, etc.), and also Protocalliphora azurea (Fallen, 1816) (Calliphoridae) and Neottiophilum praeustum (Meigen, 1826) (Neottiophilidae) known as bloodsucking ectoparasites of nestlings. Larvae of P. azurea (up to 121 per nest) were found in both early (April–May) and late (May–June) nests. Larvae of N. praeustum (up to 299 per nest) were recorded only in late nests. The two species occurred both separately and jointly in one nest, with N. praeustum dominating numerically. The seasonal differences in the development of these two parasitic species may account for their high abundance in such ephemeral habitats. Larvae of Trypocalliphora braueri (Hendel, 1901), a subcutaneous parasite of nestlings of many bird species, were not found in the fieldfare nests. A key to the larvae of the three fly species parasitizing nestlings in European Russia is given.

It is shown that low-energy beams with a high efficiency in a wide range of beam currents can be obtained in electron sources with a hollow cathode in the forevacuum pressure range. By varying the geometrical parameters of the electrode system and electromagnetic optics of the electron source, we succeeded in reaching the efficiency at a level of 0.9 for an accelerating potential of 1 kV and beam currents from 100 to 300 mA. The parameters affecting most strongly the efficiency and stability of operation of the electron source with a hollow cathode have been determined.

We construct a computably enumerable partial ordering having neither computably enumerable maximal chains nor computably enumerable maximal antichains.

Thermo-EMF, magnetothermo-EMF, magnetoresistance, and magnetization of single-crystal samples of Nd(1–x)Sr x MnO3 and Sm(1–x)Sr x MnO3 with 0 ≤ x ≤ 0.3 have been studied experimentally. A sharp increase in the thermo-EMF and giant magnetothermo-EMF and magnetoresistance has been observed near the Curie point T C in compounds with 0.15 ≤ x ≤ 0.3. At the same time, no peculiarities have been found in compositions with x = 0. Since compounds with x > 0 consist of ferromagnetic clusters of the ferron type that reside in an antiferromagnetic A-type matrix, this means that the sharp increase in the thermo-EMF near T C is caused by ferrons. Indeed, the disappearance of ferrons due to a magnetic field or heating above T C leads to an abrupt decrease in the thermo-EMF. Therefore, thermo-EMF in alloyed magnetic semiconductors has been determined by the impurity concentration and the sample volume.

The first data on blood-sucking ectoparasitic larvae of Neottiophilum praeustum (Meig.) which develop in bird nests are presented in Russia, with the fieldfare Turdus pilaris L. as a host example. Larval development takes not more than 10–12 days but no puparia are formed until late autumn. The larvae of Neottiophilum resemble those of calliphorid flies both in body structure and life mode. The main diagnostic characters of Neottiophilum larvae distinguishing them from calliphorid ones are the spiracular disk of the posterior spiracles being positioned dorsal rather than ventral to the stigmal plate and lying outside rather than inside its peritreme. In addition, the anterior spiracles have 14–15, rather than 3–8 spiracular chambers.

Immobilization of phototrophic microogranisms: microalgae (MA) and cyanobacteria (CB) on polyethylenimine (PEI)-based sorbents was studied. For this purpose, 3 insoluble porous polymeric materials were synthesized by cross-linking of PEI with epichlorohydrine and immobilization of PEI on the surface of styrene–divinylbenzene copolymer. The sorbent on the basis of cross-linked PEI was also alkylated with hexadecyl bromide to achieve hydrophobicity of its surface. The analysis of kinetics and efficiency of immobilization assessed for the model MA and CB cultures revealed the significant difference in the sorption activity of different types of sorbents depending on their synthesis procedure, chemical composition and hydrophilic-hydrophobic properties of polymeric surface. The hydrophobic sorbent obtained by immobilization of PEI on the surface of styrene–divinylbenzene copolymer characterized by very low sorption activity towards CB and MA cells. The highest immobilization efficiency of phototrophic cells was achieved for the hydrophilic sorbent on the basis of PEI cross-linked with epichlorohydrine, which provided the attachment of 50–70% of cells during 3 h of incubation. The hydrophobic sorbent based on alkylated cross-linked PEI effectively immobilized CB cells, while the colonization of the polymer surface by MA cells was very scarce. The noticed effect is explained by difference in prokaryotic (CB) and eukaryotic (MA) types of surface structures organization. Assessment of photosynthetic activity of immobilized MA cells by pulse-modulated fluorometry showed that hydrophobic sorbents had no toxic effect on the cells, while toxicity of hydrophilic cross-linked PEI-based sorbent was observed only after long-term cultivation ofphototrophic cells with this sorbent.

We prove the embeddability of the structure of Turing degrees into the structure of degrees of existential interpretability. The notion of weakly bounded Turing reducibility (wbT-reducibility) arises in the proof naturally. We demonstrate that this reducibility is situated strictly between the bounded truth-table reducibility and Turing reducibility and differs from the truth-table reducibility.

Synthetic ligands carrying a positive charge and capable of selective binding of bacterial endotoxins are covalently immobilized on surfaces of domestic hemosorbent Styrosorb-514 based on hypercrosslinked polystyrene. It is shown that the resulting sorbent aimed at treating sepsis exceeds imported specific hemosorbent in Toraymyxin™ columns in removing lipopolysaccharides, and can be used in domestically-produced Desepta columns.

Thermopower, magnetothermopower, resistivity, magnetoresistance, and magnetization of singlecrystalline samples of the Sm1–xSrxMnO3 system (x = 0.15, 0.2, 0.25, 0.3) have been experimentally studied. These compositions consist of ferromagnetic clusters of the ferron type dispersed in the A-type antiferromagnetic matrix. Colossal thermo- and negative magnetothermopower values reaching 94.5% in a composition with x = 0.3 in the region of Curie point TC in a magnetic field of 1.323 T. This result implies that thermopower is mostly related to ferron-type clusters, since their breakage under the action of magnetic field or heating above TC leads to a sharp decrease in thermopower values. These results imply that thermopower in doped manganite semiconductors is determined by the concentration of impurity and volume of a sample.

In this paper, the influence of the concentration and length of chopped carbon fiber on the physical and mechanical characteristics of siloxane matrix was investigated. It is shown that the highest values can be achieved at 2–5 wt % loading of chopped carbon fiber with a length of 3 mm. In this case, the elastic modulus increases by five to eight times in comparison with unmodified composite. Destruction of such materials takes place in accordance with an adhesive–cohesive mechanism, which testifies to the existence of relative adhesion of siloxane binder to carbon fiber.

Anting is the application of ants or “substitutes” of ants by birds to their plumage. The earliest scientific reports concerning this behavior appeared in the early 19th century, but the targeted collection of facts began in the late 1930s. As a result, anting has been recorded (in nature or/and in captivity) on all but one continent for more than 200 bird species of several orders, mostly passerines. “Active” and “passive” antings are usually recognized as the two main types of this procedure. In the active procedure, birds take ants with their bill and directly smear their feathers. Other manifold (several dozen variants) living and nonliving objects are also used for active anting. The birds practicing passive anting visit ant colonies, provoke ants to attack, and allow them to pass through their plumage. For a given type of anting, the procedure consists of stereotypic movements and postures. Ants belonging to the subfamily Formicinae (mostly Formica, Lasius, and Camponotus), which spray or exude formic acid in attack and defense, are predominantly used, whereas Dolichoderinae and Myrmicinae take second and third places, respectively. Although anting can be studied by manipulative experiments with captive birds, the functions of this behavior remain unclear. It has been suggested that anting acts as way of (1) ridding of ectoparasites, (2) feather grooming, (3) decreasing skin irritation during molt, (4) food preparation (removing pungent effluents from ant bodies before eating them), (5) sensory self-stimulation, etc. However, convincing support for any of the hypotheses is still absent.

The thermopower α and magnetothermopower Δα/α have been studied on single-crystal Sm0.55Sr0.45MnO3 samples consisting of three types of magnetic clusters (ferromagnetic clusters with the Curie temperature TC = 134 K, the A-type antiferromagnetic clusters with the Neel temperature TNA ≥ TC, and the CE-type antiferromagnetic clusters with TNCE = 240 K). The temperature dependences of α and Δα/α have extremes in the vicinity of TNCE, namely, a wide maximum in curve α(T) and a sharp minimum in curve{Δα/α}(T). The negative magnetothermopower in the minimum has a giant value of 50% in the magnetic field of 13.2 kOe. The thermopower is shown to be mainly due to the existence of the CE-type antiferromagnetic clusters, in which there is a charge-orbital ordering that displaces the oxygen atoms. The changed crystal lattice inside these clusters changes the value of the thermopower inside them. This thermopower influences the voltage drop across the sample during measuring the thermopower and, thus, the effective value of α of the whole sample. The application of a magnetic field near TNCE accelerating the destruction of the CE-type antiferromagnetic order causes the sharp decrease in the thermopower of the whole sample. This implies that the CE-type antiferromagnetic clusters with the charge-orbital ordering make main contribution to the thermopower of the whole sample.

For arbitrary tuples of real parameters \(\bar p\), we prove the existence and effective infiniteness of the class of the linear orders on ℝ of type 〈ℝ

We prove that the semigroup of all functions from the set of natural numbers to natural numbers by composition has no one-valued Σ-presentations with parameters over the hereditarily finite superstructure over the real numbers.

The magnetocaloric effect (MCE) in La1 − xSrxMnO3, Sm0.55Sr0.45MnO3, and PrBaMn2O6 compounds is studied. The maximum values of MCE (ΔTmax) determined by a direct method in the second and third compositions and in La0.9Sr0.1MnO3 are found to be much lower than those calculated from the change of the magnetic part of entropy in the Curie temperature (TC) and the Neel temperature (TN) range. The negative contribution of the antiferromagnetic (AFM) part of a sample in the La1 − xSrxMnO3 system at 0.1 ≤ x ≤ 0.3 decreases ΔTmax and changes the ΔT(T) curve shape, shifting its maximum 20–40 K above TC. Lower values of ΔTmax are detected in the range TC = 130−142 K in polycrystalline and single-crystal Sm0.55Sr0.45MnO3 samples cooled in air. If such samples were cooled in an oxygen atmosphere (which restores broken Mn-O-Mn bonds and, thus, increases the volume of CE-type AFM clusters), the maximum in the temperature dependence of MCE is located at TN (243 K) for CE-type AFM clusters. A magnetic field applied to a sample during the MCE measurements transforms these clusters into a ferromagnetic (FM) state, and both types of clusters decompose at T = TN. The PrBaMn2O6 composition undergoes an AFM-FM transition at 231 K, and the temperature dependence of its MCE has a sharp minimum at T = 234 K, where MCE is negative, and a broad maximum covering TC. The absolute values of MCE at both extrema are several times lower than those calculated from the change in the magnetic entropy. These phenomena are explained by the presence of a magnetically heterogeneous FM-AFM state in these manganites.

The conditions for equivalent positions on the (hkl) face of growing crystal are derived using symmetry elements of the space group. It is shown by the example of the sp. gr. D2h16 that the conditions of equivalent position formation coincide with conditions of the reflection of diffracted beams by crystal. It is established that electron spin resonance (ESR) centers in barite, SO4− (I) and SO4− (II), with only two conjugate spectra with equal intensity out of four, and SO4− (III), with a different intensity of conjugate spectra KαM = 2, are localized into the growth pyramid of the (001) face with a [010] step. SO2−, SO3−,, and SO4− (IV) centers, having an identical intensity of the conjugate ESR spectra with KαM = 2, are localized into the growth pyramid of the (210) face with a growth step [001].

Spontaneous generation of electric voltage has been found in a Sm0.55Sr0.45MnO3 single crystal grown by floating zone melting with cooling in oxygen. The maximum voltage of 60 μV has been observed in the region of temperatures corresponding, simultaneously, to destruction of the CE-type antiferromagnetic ordering and charge ordering in some clusters. The maximum voltage remains unchanged for 24 h and decreases by 45% in a magnetic field of 14.2 kOe. It has been shown that the spontaneous voltage is caused by the presence of regions with different electric charges in the sample.

The magnetocaloric effect ΔT has been studied by a direct method in two samples of the manganite Sm0.55Sr0.45MnO3, namely, a single crystal (sample A) and a ceramic sample (sample C). The temperature dependences of the ΔT effect of both samples exhibit a maximum at T max = 143.3 K for the sample A and T max = 143 K for the sample C. In these maxima, the values of the ΔT effect are 0.8 and 0.4 K in the magnetic field H = 14.2 kOe for the samples A and C, respectively. In addition, the ΔT(T) curve of the sample A has a minimum at T min = 120 K, in which ΔT = −0.1 K. The maximum value of the ΔT effect increases with an increase in the magnetic field H in the range of magnetic fields up to 14.2 kOe, and the rate of this increase at H > 8 kOe is higher than that at H < 8 kOe. These features of the ΔT effect are explained by the presence of ferromagnetic and antiferromagnetic A- and CE-type clusters in the samples.

The influence of the temperature and ferromagnetic ordering on the adsorption of Fe, Co, and Ni transition metal ions on a copper paramagnetic substrate with the formation of a submonolayer film is described in terms of the spin-density functional theory for the first time. The conditions for the formation of magnetic monoatomic films stable with respect to island adsorption with a change in the coverage parameter Θ are revealed. Four model cases of the electron density distribution as a function of the equilibrium distance between the film and the substrate and the equilibrium thickness of the adsorption layer are considered. It is demonstrated that the inclusion of the ferromagnetic ordering substantially affects the adsorption energy and leads to its considerable increase.

The effect of temperature on the adsorption of magnetic ions of transition metals on a paramagnetic metallic substrate is described for the first time with allowance for the effects of ferromagnetic ordering in a submonolayer film. Conditions have been determined necessary for the formation of magnetic monatomic films stable relative to the island adsorption with changes in the coverage Θ. Four model cases of electron-density distribution depending on the equilibrium distance between the film and the substrate and the equilibrium thickness of the adsorption layer are considered. It is shown that the allowance for the effects of ferromagnetic ordering exerts a substantial influence on the adsorption energy, leading to its noticeable increase.

The spectral measuring facility with a new Fourier analyzer for use with the radio telescope RATAN-600 is described and its experimental data are reported.

Mechanisms underlying the effect of Tb3+ and Eu3+ ions on the efficiency of 1.54-μm luminescence of Er3+ ions in ZBLAN glass were studied. The cross-relaxation coefficients were measured. The ion-ion interaction channels considered were used to construct coupled balance equations describing the variation in ion level population. The optimum concentrations of the dopants were found. The experimental data obtained and theoretical estimates evidence the possibility of increasing the population of the 4 I 13/2 state of the Er3+ ion, which would enable development of more efficient erbium-based amplifiers in the case of excitation at the wavelength of 0.975 μm.