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By cyclic gas treatment in ammonia and in air, a composite surface layer with controlled structure may be formed on die steel. Thanks to the catalytic properties of the oxide film that appears, an extended multilayer region of chemical compounds is formed at its surface. That improves the erosion and crack resistance of the die steel, with corresponding increase in the life of hot-working dies by a factor of 2–2.5.

The reflectance spectra of five near-Earth asteroids, one Mars crosser, and four classical asteroids of the main belt in the range 0.35–0.95 µm have been observed, calculated, and analyzed. Asteroids with a magnitude up to 17 were observed in 2013–2017 with a 2-m telescope with a CCD spectrograph with extremely low spectral resolution (R ∼ 100) of the Terskol Observatory of the Institute of Astronomy of the Russian Academy of Sciences in order to determine their taxonomic types and composition. These results show that the composition of some of the studied near-Earth asteroids is heterogeneous judging by the variations in their reflectance spectra within adjacent taxonomic classes. It is notable that some of these asteroids are binary. The physical and chemical-mineralogical interpretation of reflectance spectra is presented.

This paper presents the results that confirm the sublimation activity at the perihelion of the primitive main-belt asteroids 779 Nina, 704 Interamnia, and 145 Adeona; this activity was first discovered in September 2012 (Busarev et al., 2015; Busarev et al., 2016). The new spectrophotometric and/or UBVRI photometric observations of Nina, Interamnia, and Adeona were carried out in 2016–2018 during a regular perihelion passage of these asteroids. Additionally, probable spectral signs of weak sublimation activity were discovered on another two primitive main-belt asteroids, 51 Nemausa and 65 Cybele. In this study, we discuss the conditions for the occurrence of a periodic and/or continuous sublimation process on main-belt asteroids with low-temperature mineralogy; in particular, the conditions that are associated with their formation close to the “snow line” or beyond. We also consider general evolution processes that are able sustain a sufficiently high concentration of water ice close to the surface of the bodies in question and, therefore, their continuous sublimation activity, or lead to the recurrence of extinct activity.

We present the first search for bosonic superweakly interacting massive particles (super-WIMPs) as keV-scale dark matter candidates performed with the GERDA experiment. GERDA is a neutrinoless double-β decay experiment which operates high-purity germanium detectors enriched in Ge76 in an ultralow background environment at the Laboratori Nazionali del Gran Sasso (LNGS) of INFN in Italy. Searches were performed for pseudoscalar and vector particles in the mass region from 60 keV/c2 to 1 MeV/c2. No evidence for a dark matter signal was observed, and the most stringent constraints on the couplings of super-WIMPs with masses above 120 keV/c2 have been set. As an example, at a mass of 150 keV/c2 the most stringent direct limits on the dimensionless couplings of axionlike particles and dark photons to electrons of gae<3×10−12 and α′/α<6.5×10−24 at 90% credible interval, respectively, were obtained.

We describe and analyze simultaneous sublimation activity of the main-belt primitive asteroids during their perihelion passages, which was detected by spectral methods. This phenomenon was observed for the first time in September 2012 for asteroids (145) Adeona, (704) Interamnia, (779) Nina, and Mars-crosser (1474) Beira ( Busarev et al., 2015 , Busarev et al., 2016 , Busarev et al., 2018 , Busarev et al., 2019a ). By our recent observations of (704) Interamnia, (24) Themis, and (449) Hamburga performed in March–April 2019, we confirmed the existence of this effect. (24) Themis and (449) Hamburga was detected as active for the first time. Never before, two or more asteroids have been observed active simultaneously. Activity on asteroids reveals itself by unusual spectral features (the maxima at approximately 0.40–0.50 and/or 0.60–0.70 μm), which appear in the reflectance spectra of the bodies when they approach perihelion. We explain them as manifestations of sublimation of ice materials and development of a subtle exosphere around the asteroids. Moreover, from numerical simulations of the light scattering in a medium containing ice and silicate/organic dust particles of complex structure, we found that some of these models fit well the reflectance spectra of active asteroids, which confirms the presence of a rarefied exosphere around these bodies. Our results show that the main conditions providing formation of a temporal sublimation-driven exosphere around primitive main-belt asteroids are: (1) the considerably higher content of H2O in their material than that previously believed from accounting for only the content of bound water in composition of carbonaceous chondrites, as possible components of asteroids; (2) frequent collisions of main-belt asteroids with smaller bodies and/or exposure to meteorite fluxes, which leads to excavation of ices and their subsequent sublimation; (3) the recurrent rise of the subsolar temperature on the surface of asteroids under proper orbital or dynamical parameters and the sublimation of subsurface ices (if present); and (4) the strengthening of solar activity (and the accompanying factors), which results in desiccation, destruction and/or dispersion of hydrated silicates and/or radiation damage of organic films isolating stocks of volatiles on or under the asteroid surface. According to our analysis, none of these factors produces a noticeable effect alone and can be marked as stronger or more frequent, but two or three of them working simultaneously may be effective.

A technique for the formation of diffusion layers based on zinc on the surface of low-carbon low-alloy steels for their corrosion protection is considered. The possibility of the formation of dense corrosion-resistant coatings with a smooth hardness gradient through depth by diffusion zinc-plating combined with gas nitriding is studied.

Among 11 673 of near-Earth objects (NEOs), 52 asteroids are identified, which, together with the Eccentrids meteor system, comprise a single population of small bodies of the Solar System with the smallest orbits of high eccentricity. Some features of this unique system of bodies are discussed in this paper. The distribution of perihelion longitudes is studied for the given group of asteroids and compared to that of the Aten asteroids, which are the most similar to the Eccentrids. The dependence is obtained of the character of perihelion longitude distribution on the eccentricities of the NEO orbits. Eight asteroid stream of the Eccentrids are found. The Eccentrids asteroids approaching the Earth’s orbit along its whole length in their aphelia can pose a certain hazard for the Earth.

Six asteroids including two NEAs, one of which is PHA, accessible for observation in September 2012 were investigated using a low-resolution (R ≈ 100) spectrophotometry in the range 0.35–0.90 μm with the aim to study features of their reflectance spectra. A high-altitude position of our Terskol Observatory (3150 m above sea level) favorable for the near-UV and visible-range observations of celestial objects allowed us to probably detect some new spectral features of the asteroids. Two subtle absorption bands centered at 0.53 and 0.74 μm were found in the reflectance spectra of S-type (32) Pomona and interpreted as signs of presence of pyroxenes in the asteroid surface matter and its different oxidation. Very similar absorption bands centered at 0.38, 0.44 and 0.67–0.71 μm have been registered in the reflectance spectra of (145) Adeona, (704) Interamnia, and (779) Nina of primitive types. We performed laboratory investigations of ground samples of known carbonaceous chondrites, Orguel (CI), Mighei (CM2), Murchison (CM2), Boriskino (CM2), and seven samples of low-iron Mg serpentines as possible analogs of the primitive asteroids. In the course of this work, we discovered an intense absorption band (up to ∼25%) centered at 0.44 μm in reflectance spectra of the low-Fe serpentine samples. As it turned out, the equivalent width of the band has a high correlation with content of Fe3+ (octahedral and tetrahedral) in the samples. It may be considered as a confirmation of the previously proposed mechanism of the absorption due to electronic transitions in exchange-coupled pairs (ECP) of Fe3+ neighboring cations. It means that the absorption feature can be used as an indicator of ferric iron in oxidized and hydrated low-Fe compounds on the surface of asteroids and other atmosphereless celestial bodies. Moreover, our measurements showed that the mechanism of light absorption is partially or completely blocked in the case of intermediate to high iron contents. Therefore, the method cannot probably be used for quantitative estimation of Fe3+ content on the bodies. Based on laboratory study of the analog samples, we conclude that spectral characteristics of Adeona, Interamnia, and Nina correspond to a mixture of CI–CM-chondrites and hydrated silicates, oxides and/or hydroxides. Spectral signs of sublimation activity on Adeona, Interamnia, and Nina at minimal heliocentric distances are likely discovered in the short-wavelength range (∼0.4–0.6 μm). It is suggested that such cometary-like activity at the highest surface temperatures is a frequent phenomenon for C and close type asteroids including considerable amounts of ices beneath the surface. A usual way of origin of a temporal coma of ice particles around a primitive asteroid is excavated fresh ice at recent impact event(s). The obtained reflectance spectra of two NEAs, (330825) 2008 XE3 and 2012 QG42, are predominantly featureless and could be attributed to S(C) and S(B)-type bodies, respectively. We discuss reasons why weak spectral features seen in reflectance spectra of the main-belt asteroids are not observed in those of NEAs.

The GERDA collaboration is performing a sensitive search for neutrinoless double beta decay of $^{76}$Ge at the INFN Laboratori Nazionali del Gran Sasso, Italy. The upgrade of the GERDA experiment from Phase I to Phase II has been concluded in December 2015. The first Phase II data release shows that the goal to suppress the background by one order of magnitude compared to Phase I has been achieved. GERDA is thus the first experiment that will remain background-free up to its design exposure (100 kg yr). It will reach thereby a half-life sensitivity of more than 10$^{26}$ yr within 3 years of data collection. This paper describes in detail the modifications and improvements of the experimental setup for Phase II and discusses the performance of individual detector components., 31 pages, 34 figures

The basic science of astronomy and, primarily, its branch responsible for studying the Solar System, face the most important practical task posed by nature and the development of human civilization—to study space hazards and to seek methods of counteracting them. In pursuance of the joint Resolution of the Federal Space Agency (Roscosmos) and the RAS (Russian Academy of Sciences) Space Council of June 23, 2010, the RAS Institute of Astronomy in collaboration with other scientific and industrial organizations prepared a draft concept of the federal-level program targeted at creating a system of space hazard detection and counteraction. The main ideas and astronomical content of the concept are considered in this article.

The GERmanium Detector Array (GERDA) experiment is searching for the neutrinoless double beta decay ( 0νββ ) of the isotope 76 Ge. High-purity germanium crystals enriched in 76 Ge, simultaneously used as source and detector, are directly deployed into ultra-pure, cryogenic liquid argon, which acts both as cooling medium and shield against the external radiation. The second phase of the experiment is taking data since end of 2015 with 20 additional kg of custom-made BEGe-type Germanium detectors and an active LAr veto. In this paper we will summarize the results of the last data release of June 2017. No evidence for a possible signal is found: the lower limit for the half-life of 76 Ge is 8.0·1025 yr at 90% CL. The very low residual background found at the Q -value of the decay, about 10-3 cts/(keV · kg · yr), makes Gerda the first experiment in the field to be background-free for the complete design exposure of 100 kg · yr.

The primary physical and chemical processes which follow photoexcitation of the covalently linked systems, 1-[(4-azido-2,3,5,6-tetrafluorobenzoyloxy)methyl]pyrene (2) and 1-[3-(4-azido-2,3,5,6-tetrafluorobenzoyloxy)propyl]pyrene (3), have been studied using femto- and nanosecond transient absorption spectroscopy and computational chemistry. Excitation of 2 and 3 at 336 nm results in the population of the second excited singlet state of the pyrene moiety (S2). Internal conversion to the lowest excited singlet state of the pyrene moiety (S1) occurs with a time constant of ∼140 fs, a value which is similar to that of unsubstituted pyrene. The S1 local pyrene state, initially formed with excess vibrational energy, undergoes vibrational cooling with a time constant ∼2 ps. The decay of the local pyrene S1 state measured in the pump-probe experiments was described by a two exponential function with time constants which agree well with the values obtained previously from the fluorescence decay kinetics (Barabanov, I. I.; Pritchina, E. A.; Takaya, T.; Gritsan, N. P. MendeleeV Commun. 2008, 18, 273). In both systems decay of the local pyrene S1 state on the time scale of tens of picoseconds is accompanied by formation of a product with a narrow band at ∼460 nm. This transient absorption was assigned to the radical cation of the pyrene moiety. Calculations predict very fast dissociation of the counterpart aryl azide radical anion with formation of the corresponding arylnitrene radical anion. Decay of the local pyrene S1 state on the longer time scale (hundreds of ps) is not accompanied by formation of a noticeable amount of pyrene radical cation. Most likely, both electron transfer and energy transfer from pyrene to aryl azide moiety are responsible for the photosensitization of the perfluorinated aryl azide decomposition.

Synthesis was developed of perylene series luminophors containing in the perylene core simultaneously a cyano group and N,N-dimethylaniline residue.

The issue of the presence of meter- and decameter-sized bodies in meteor and fireball streams is of fundamental importance in the context of the theory of disintegration of parent bodies. Our observations, which have been carried out since 1995, indicate that such bodies are present in the Perseid, α-Capricornid, Leonid, and Coma-Berenicid meteoric streams. A catalogue is presented here for the parameters of the detected bodies. The spatial density of the meter-sized bodies is estimated based on the observational material. Within the errors, our estimates agree with the estimates based on the extrapolation of meteor and fireball data. An analysis of the observations suggests some inferences on the structure of the streams under study.

Methods for the preparation and various transformations of acetylenic derivatives of quinones, which are key intermediates in the synthesis of fused heterocyclic quinoid structures and some highly unsaturated compounds, are surveyed in detail. The bibliography includes 114 references.

On the basis of experimental data and of quantum-chemical calculations, a principal scheme for the mechanism of cyclization of vic -alkynylanthra- and vic -alkynylnaphthoquinone diazonium salts resulting in the formation of 5- and 6-membered heterocycles is proposed. Within the framework of the new notions of the reaction mechanism, a possibility of controlling the formation of condensed pyrazole or pyridazine rings is demonstrated.

Minor bodies that, at the present stage, have orbital characteristics similar to those of the Prřibram meteorite and that differ from it in the date of activity of the radiants by no more than a 1.2-month period in either direction were detected on the basis of catalog data on the orbits of asteroids, individual fireballs, and fireball and meteor streams obtained from photographic observations. The following objects comprising the Prřbram family are among such minor bodies: three asteroids (1863, 4486, and J98S70J) of the Apollo group, three fireball streams, five meteor streams, and ten fireballs. This extensive system of bodies consists of three branches: a Northern (N), an Ecliptical (Q), and a Southern (S) Branch. The family of meteor streams associated with the periodic comet Pons–Winnecke appears to be related to this family. Thus, there emerges an intricate complex of small bodies that is similar to the well-known Taurid complex. In the distribution of various populations of minor bodies according to the quantity c of the Tisserand criterion, both of these complexes of minor bodies, like the group of cometoids (or cometlike asteroids), are situated in the region of unstable motion or, to be more exact, near the gap that arises in the L2 and L3 collinear points of libration.

The microstructure, the thickness of the nitrided layer, and the microhardness of a group of corrosion-resistant steels are studied after diffusion saturation in an ammonia-air atmosphere. It is shown that the use of such an atmosphere makes it possible to reduce the duration of the process of nitriding by a factor of 3.5 – 4 as compared to nitriding in dissociated ammonia.

The possibility of the heterocyclization of vic -alkynylanthraquinonediazonium salts with the formation of a 5- or 6-membered ring, depending on the reaction conditions, is established. The heterocyclization of 2-alkynyl-9,10-anthraquinone-1-diazonium salts to form 1 H -naphtho[2,3- h ]cinnoline-4,7,12-triones is reported.

When heated in piperidine, 1-amino-2-(3-hydroxyalk-1-ynyl)-9,10-anthraquinones undergo cyclization into 2-(1-hydroxyalkyl)naphtho[2,3-g]indole-6,11-diones. In contrast, 1-amino-2-(3-hydroxy-3-phenylpropynyl)-9,10-anthraquinone reacts with primary and secondary amines to give the corresponding 1-amino-2-(1-amino-2-benzoylvinyl)-9,10-anthraquinones, which undergo cyclization into 4-dialkylamino- or 4-alkylamino-2-phenylnaphtho[2,3-h]quinoline-7,12-diones. Heating of the starting phenylpropynol with Et3N causes its dehydrogenation and isomerization.

The concept of Space Debris is tightly connected with the rapidly developing activity of men in space, and accompanied by a contamination of the surrounding space by artificial debris. Besides artificial debris, in the vicinity of the Earth is moving a large number of natural celestial bodies: comets, mini-comets, asteroids, meteor streams with fragments of various sizes and chemical composition. Our activity in the observations concentrates in three directions: position observations of artificial objects on the geostationary orbit (GEO); photometric observations on GEO and LEO (low orbits); observations of natural near-Earth objects (NEO). Scientific investigations are carried out in the following directions: explosions of upper stages of rockets in LEO and GEO; solar radiation pressure and its influence on the evolution of orbits; space debris on GEO; natural objects' population in near-Earth space.

Heterocyclization of 3-diethylamino-6-heptyn-1-yl-1,4-naphthoquinone-5-diazonium chloride results in the formation of five- or six-membered ring containing products depending on the reaction conditions. A common intermediate was isolated. Possible reaction mechanisms are discussed.

The bridged systems containing pyrenyl and aryl azido residues have been synthesized for the first time, and the quenching of pyrene fluorescence on a picosecond time scale has been observed.

Lead tetraacetate oxidation of pyrene followed by hydrolysis affords 1-hydroxypyrene whose esterification with 4-azidobenzoic acid gives a new bifunctional luminophore characterized by UV and luminescence spectroscopy.

The addition of secondary and primary amines to ethyl (1-amino-9,10-anthraquinon-2-yl)propynoate affords an easily separable mixture of the corresponding ethyl 3-dialkylaminoor 3-alkylamino-3-(1-amino-9,10-anthraquinon-2-yl)acrylate and 3-dialkylamino- or 3-alkylaminonaphthol[2,3-h]quinoline-2(1H), 7,12-trione (in ∼4: 1 ratio). Intramolecular cyclization of the resulting substituted ethyl acrylates results in the formation of 4-dialkylaminoor 4-alkylamino-2-chlorinated pyridine rings. Subsequent nucleophilic substitution of the chlorine atom gives 2-functionalized 4-dialkylamino- or 4-alkylaminonaphtho[2,3-h]quinoline-7,12-diones.

Glass ceramic materials that can be used as ceramizing binders for abrasive tools with heat treatment temperatures of 650°C have been developed and tested. Their main physicochemical properties have been investigated.

Even flow: Photoinduced symmetry-breaking charge separation takes place in a few picoseconds in a 1,3-bis(perylene)propane dyad in polar solvents. Polarized transient absorption measurements show that the direction of the charge flow is random and entirely governed by the fluctuations of the solvent orientation around the dyad.

When heated in piperidine, 1-amino-2-(3-hydroxyalk-1-ynyl)-9,10-anthraquinones undergo cyclization into 2-(1-hydroxyalkyl)naphtho[2,3-g]indole-6,11-diones. In contrast, 1-amino-2-(3-hydroxy-3-phenylpropynyl)-9,10-anthraquinone reacts with primary and secondary amines to give the corresponding 1-amino-2-(1-amino-2-benzoylvinyl)-9,10-anthraquinones, which undergo cyclization into 4-dialkylamino- or 4-alkylamino-2-phenylnaphtho[2,3-h]quinoline-7,12-diones. Heating of the starting phenylpropynol with Et3N causes its dehydrogenation and isomerization.

General regularities and scope of reactions carbanions with the ester group at carbanionic center and arylisocyanates resulting formation of carbamates by C N migrations of ester groups have been described. The use of tosylisocyanates terminated reactions at the first stage with formation of corresponding tosylacylamides. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:119–125, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20585

Mixtures of alkyl esters of 2-triethylsilyl(germyl)- and ( E )-3-triethylsilyl(germyl)acrylic acids were obtained by hydrosilylation and hydrogermylation of alkyl esters of propiolic acids. Alkyl esters of organosilicon(germanium) β-amino(hydrazino)propionic acids were obtained by amination of the alkyl esters of 2-triethylsilyl(germyl)acrylic acids.

The bridged systems containing pyrenyl and aryl azido residues have been synthesized for the first time, and the quenching of pyrene fluorescence on a picosecond time scale has been observed.

Triethylbenzylammonium chlorometallates [Et3NCH2Ph][MCln]m− (M = Pt, Pd, Rh, Ir, Fe, Co, Cu, m = 1–3, n = 3–6), polymer-anchored ionic metal complexes [℗—CH2PBu3][MCln]n− and some other chlorometallates and complexes of platinum, rhodium, ruthenium and osmium were studied as catalysts in the hydrogermylation of phenylacetylene with triethylgermane. All the complexes containing platinum, palladium and rhodium were found to be effective catalysts. The cis/trans ratio of the products obtained is determined by the metal atom involved and decreases in the following order: Ir > Rh ≫ Pd > Pt.

Two neutrino double beta decay of $^{76}$Ge to excited states of $^{76}$Se has been studied using data from Phase I of the GERDA experiment. An array composed of up to 14 germanium detectors including detectors that have been isotopically enriched in $^{76}$Ge was deployed in liquid argon. The analysis of various possible transitions to excited final states is based on coincidence events between pairs of detectors where a de-excitation $\gamma$ ray is detected in one detector and the two electrons in the other. No signal has been observed and an event counting profile likelihood analysis has been used to determine Frequentist 90\,\% C.L. bounds for three transitions: ${0^+_{\rm g.s.}-2^+_1}$: $T^{2\nu}_{1/2}>$1.6$\cdot10^{23}$ yr, ${0^+_{\rm g.s.}-0^+_1}$: $T^{2\nu}_{1/2}>$3.7$\cdot10^{23}$ yr and ${0^+_{\rm g.s.}-2^+_2}$: $T^{2\nu}_{1/2}>$2.3$\cdot10^{23}$ yr. These bounds are more than two orders of magnitude larger than those reported previously. Bayesian 90\,\% credibility bounds were extracted and used to exclude several models for the ${0^+_{\rm g.s.}-0^+_1}$ transition.