70 research outputs found
Cottus gratzianowi Sideleva, Naseka & Zhidkov, 2015, sp. nov.
No full textCottus gratzianowi, sp. nov. (Figs 2, 3, 5, 6) Holotype. ZIN 55596, 63 mm SL; Ukhtomitsa River village of Korotetskaya (Vologda Province), 60 ° 18 ′ 19 ″N, 38 ° 40 ′ 30 ″E, Onega River drainage, White Sea basin; coll. A. Naseka & Z. Zhidkov, July 2010. Paratypes. ZIN 55597, 17 specimens, 42–60 mm SL, same data as holotype. Diagnosis. Cottus gratzianowi sp. nov. is diagnosed from all other described members of the genus Cottus in Europe east of the Meuse (except C. koshewnikowi) in having the following combination of character states: no transverse dark bands on the pelvic fin, a single median chin canal pore, an incomplete lateral line not reaching behind the anal-fin insertion, and the position of the lateral line which is located considerably above the mid-line of the flank. Cottus gratzianowi sp. nov. is distinguished from C. koshewnikowi by a larger eye (horizontal diameter 23−28 % HL, equal to or exceeding snout length vs. 16−25 % HL, less than snout length), a rounded caudal fin (vs. commonly truncated), frequent presence of one to three branched rays in median part of the pectoral fin (vs. usual absence), an interrupted supratemporal canal commissure with 4 pores (vs. non-interrupted, with 3 pores), the pelvic fin extending to the anus in both sexes (vs. not reaching the anus), a short lateral-line canal extending to below the fifth to tenth ray of the second dorsal fin, with 15−24 pores, with few interruption (vs. commonly extending to below the 9 th to 15 th ray of the second dorsal fin, with modally 21−27 pores, with few to numerous interruptions), abdominal vertebrae commonly 10 (vs. 11), and contrasting black blotches on all fins including pelvic and anal fins (vs. no blotches on pelvic and anal fins). Description. Proportional measurements of the holotype and paratypes are given in Table 1. Body humped behind head, deep and compressed; maximum body depth 4.3−5.5 times in SL (5.4 in holotype) and markedly less than HL (Figs 2, 3). Caudal peduncle length 6.8−9 times in SL (6.8 in holotype), caudal peduncle depth 1.7−2.3 times in its length (2.2 in holotype). Prickles (modified scales) numerous, located below and above lateral line; just behind pectoral base, area of prickling extended to back and gradually tapered caudad, terminating below middle of second dorsal fin. Prickle possessing roundish basis and short sharp spine. Head large, its length, only slightly less than or equal to width, 2.5−3.3 times in SL (3.3 in holotype), depressed (Fig. 2 a −c). Small and very shallow dermal tubercles on dorsal surface of head. Interbranchial space wide, 2.5−3.8 times in HL (2.7 in holotype) (Fig. 2 c). Three preopercular spines; uppermost spine longest, slightly curved upward, its length about 6 times in SL; second spine short, about 3 times in length of uppermost spine; third spine blunt and covered by skin. Snout steep and elongated, its length 3.7−5 times in HL (4.2 in holotype). Anterior nostril forming short cylindrical pigmented tube. Posterior nostril as slender tube, 3 times as small as anterior nostril. Eye relatively large, eye horizontal diameter 3.5−4.4 times in HL (4.2 in holotype), equal or greater than snout length; dorsal margin of orbit elevated. Interorbital space narrow; its width 1.2−2 times in eye horizontal diameter (1.5 in holotype) about 6.5−9.3 times in HL (6.5 in holotype). Mouth horizontal and terminal; upper jaw extending caudad to below anterior margin of pupil. Length of upper jaw 2.8−3.7 times in HL (2.8 in holotype); lower jaw slightly shorter than upper jaw. Teeth simple, conical, similar in shape and size, grouped in bands on jaws and prevomer; no teeth on palatines. Upper lip thick, lateral lip lobes well developed. Gill slit large (46−58 % HL), located completely above pectoralfin base. Outer gill rakers on first gill arch 3 or 4, small and tuberculate, covered with spines at tip. Inner gill rakers on first gill arch 4 or 5, two median gill rakers longer than marginal ones, of trapezoidal shape, laterally compressed and expanded at base, top and sides, armored with tiny sharp spines. Genital papilla of breeding males triangular, short, not reaching base of first anal ray. Three piloric caecae, one long and two short. Fin-ray counts are given in Table 2. First dorsal fin originating behind vertical through dorsal tip of opercular flap; length of first dorsal-fin base about 5−6.3 times in SL and about 2.2−3 times in length of second dorsal fin base (2.6 in holotype). No gap between end of terminal membrane of first dorsal fin and second dorsal-fin origin; length of second dorsal-fin base 2.2−2.8 times in SL (2.4 in holotype); first ray of second dorsal-fin about 3 times as short as its longest ray. First dorsal fin Second dorsal fin Anal fin Pectoral fin VI VII VIII 15 16 17 18 19 20 12 13 14 13 14 15 C. gratzianowi 2 14 * 2 4 13 * 1 12 * 6 4 * 12 2 (n= 18) C. koshewnikowi 1 19 3 2 9 11 1 8 12 3 4 16 3 (n= 23), Volga C. koshewnikowi 3 2 2 3 4 1 1 3 1 (n= 5), Northern Dvina C. koshewnikowi 5 6 3 5 2 1 3 8 2 8 1 (n= 11), Pechora Anal fin originating at short distance from anus, below third ray of second dorsal fin; length of anal-fin base about 1.3 times as short as length of second dorsal fin base, and 2.8−3 times in SL (3 in holotype), about equal to head length; length of longest anal-fin ray about equal to length of longest second dorsal-fin ray (equal in holotype). Caudal fin rounded, with 11 or 12 rays supported by hypural plate, 8 middle rays branched and upper 2 and lower 1−2 rays unbranched, and 12−14 (6−7 dorsal and 6−7 ventral) procurrent rays. Pelvic fin extending to anus; two inner soft rays longer than two outer rays; outer ray with long free tip; narrow pelvic base 7 times in length of longest pelvic-fin ray. Pectoral-fin base oblique, broad, its base about 3 times in HL; pectoral-fin length 3−3.4 times in SL (3.4 in holotype); tip of longest ray reaching below base of third or fourth ray of second dorsal fin; one to three medial (longest) rays clearly branched in 56 % of examined specimens (in holotype and 9 paratypes) (Fig. 5 a). Lateral-line system. Cephalic sensory canals developed and interconnected except preoperculo-mandibular sensory canal. Supraorbital canal pores 3 (on each side); infraorbital canal pores 8−9 (usually 8); temporal canal pores 3. Temporal canals of left and right side connected via supratemporal commissure interrupted in middle, with two paired pores instead of one; preoperculo-mandibular canal pores 11 on both sides with five paired pores and single large median pore on chin. Lateral-line canal with 15−24 pores (averaging 19.8) (Table 3), extending along dorsal profile of body, reaching below fifth to tenth ray of second dorsal fin, sometimes (in 2 specimens from 18) interrupted at very end with one or two free canal segments. Vertebrae. Abdominal vertebrae 10 or 11; caudal vertebrae 22 or 23, total 32−34 (Table 4); long, thin pleural ribs on the parapophyses of commonly three last abdominal vertebrae (Fig. 6). Predorsal 2 Abdominal Caudal vertebrae Total vertebrae vertebrae vertebrae 8 9 10 10 11 12 21 22 23 24 32 33 34 35 C. gratzianowi 2 16 * 12 6 * 6 12 * 2 14 2 * (n= 18) C. koshewnikowi 9 12 2 1 22 2 12 9 2 13 8 (n= 23), Volga C. koshewnikowi 5 5 1 4 1 4 (n= 5), Northern Dvina C. koshewnikowi 1 10 10 1 2 8 1 2 7 2 (n= 11), Pechora Colouration. Body background light olive; overall body dark mottled, blotches forming marble pattern (Fig. 2). Head dorsally dark, with dark blotches laterally similar to body. Distinct melanophores and their clusters densely located on ventral surface of head and bases of pectoral and pelvic fins. Dark spots forming transverse bands on both dorsal, pectoral and caudal fins. First dorsal-fin margin in adult males light, whitish. Distribution and habitat. The species is currently known from the Ukhtomitsa River, a tributary of the Modlona River (a Lake Vozhe tributary) in the Onega River drainage, the White See basin (Fig. 8). Cottus gratzianowi sp. nov. occurs in a relatively cool in summer small river with moderate to rapid current, gravel and cobble bottom, and not very dense submerged aquatic vegetation. Etymology. The new species is named in honour of Valerian Ivanovich Gratzianow [Gratsianov] (1876−1932), the author of the first taxonomic review of Russian fishes "Versuch einer Übersicht der Fische des Russischen Reiches in systematischer und geographischer Hinsicht" (Gratzianow 1907 a), who described Cottus koshewnikowi. We retained the original latinised spelling of the surname (Gratzianow). Comparison. Cottus gratzianowi sp. nov. belongs to C. gobio species group as possessing no transverse dark bands on the pelvic fin, a commonly single median chin canal pore and non-spatulate prickles (see Kottelat & Freyhof 2007). Freshwater sculpins from the White Sea basin have not been distinguished from Volga sculpin and appeared in literature under the name either Cottus gobio (e.g. Novoselov 2008; Novoselov et al. 2013; Parin et al. 2014) or C. koshewnikowi (e.g., Kottelat & Freyhof 2007). Cottus gratzianowi sp. nov. and C. koshewnikowi share an incomplete lateral line not reaching behind the anal-fin insertion and located considerably above the mid-line of the flank. Cottus gratzianowi sp. nov. form the Onega River drainage is distinguished from C. koshewnikowi from the Volga (type locality) by a set of the following character states. Cottus gratzianowi sp. nov. possesses a larger eye: eye horizontal diameter, 23−28 (mean 25) % HL, is equal to or exceeds snout length, 20−27 (mean 24) % HL (vs. eye diameter less than snout length, 16−23, mean 19, and 22−28, mean 25, respectively) (Table 1), a rounded caudal fin (vs. truncated) (Fig. 3, 4), the pelvic fin extending to the anus in both sexes (vs. not reaching the anus), frequent presence of one to three branched rays in median part of the pectoral fin (56 % of specimens vs. 0 to 2 %) (Fig. 5), the supratemporal canal commissure often interrupted in the middle and possessing 4 pores (vs. noninterrupted, with 3 pores), a short lateral-line canal extending to below the fifth to tenth ray of the second dorsal fin, with 15−24 pores (vs. extending to below the ninth to fifteenth ray of the second dorsal fin, with 21−27 pores) (Table 3). Only six from 18 (33 %) specimens of C. gratzianowi sp. nov. have the lateral-line canal slightly interrupted at its end with one or two free canal segments while C. koshewnikowi commonly (94 % of specimens) have the lateral line considerably interrupted with two to nine free segments in its posterior section. Post-pectoral prickling in C. gratzianowi sp. nov. is dense and occupies a wider area than in C. koshewnikowi where prickels are sparse and located only under the pectoral fin. The new species has contrasting black blotches on all fins including the pelvic and anal fins while no blotches on either pelvic or anal fin are developed in C. koshewnikowi. There are also some differences in fin-ray counts between C. gratzianowi sp. nov. and C. koshewnikowi from the type locality (Table 2), the former having lower numbers of second dorsal-fin rays (15−18, averaging 16.8, vs. 16−20, averaging 17.5) and anal-fin rays (12−13, averaging 12.3, vs. 12−14, averaging 12.8). In the new species, total vertebrae are 32−34 similar to C. koshewnikowi from the Volga but in C. gratzianowi sp. nov. the number of abdominal vertebrae is most often 10 (averaging 10.3) vs. commonly 11 in Volga C. koshewnikowi (averaging 11.0) while the number of caudal vertebrae is commonly 23 (averaging 22.7) vs. 21−23, commonly 22 (averaging 22.3). This vertebral feature, a longer caudal region, in combination with a shorter anal fin (commonly 12 rays vs. 13, see Table 2) determines a relatively longer caudal peduncle in the new species as shown above (mean 12.8 % SL vs. 8.7 % SL, see Table 1). The new species and the Volga C. koshewnikowi are well discriminated by a complex of morphometric characters as can be seen from results of a DFA presented below. As to sculpins from other rivers of the Arctic basin in Europe, an opinion was expressed that the sculpin from the Pechora River may represent a distinct species, Cottus milvensis Soldatov, 1924, though no distinguishing characters were given (Kottelat & Freyhof 2007). Soldatov (1924) recorded Cottus gobio in the Pechora River, while two juvenile specimens from the Mylva tributary were described by him as a new subspecies C. gobio milvensis (whereabouts of the syntypes are unknown). These two specimens differed from the fish identified as C. gobio gobio by a complete lateral line, longer both dorsal and anal fins, and some departure in the prickling. All specimens we examined (18 in total available at ZIN, see below in the list of material) were tentatively identified by us as C. koshewnikovi. Volga and Pechora specimens share most diagnostic characters (e.g., a smaller eye) mentioned above in the comparison between C. gratzianowi sp. nov. and Volga C. koshewnikovi as can be seen from Tables 1−4. However, the Pechora specimens differ from the Volga specimens in having a slightly longer second dorsal fin, 16−19 rays vs. 17−19, though mode value, 18, is the same (Table 2), a markedly longer caudal peduncle (11−20 % SL)−longer than in C. gratzianowi sp. nov. and, accordingly, a longer caudal vertebral region, 22−24, modally 23. The number of total vertebrae, 33−35, modally 34, is higher in the Pechora specimens than in the Volga sample. This feature needs a further study based on a more numerous material. However, the number of abdominal vertebrae is 11 in the Pechora sample (a character state typical of C. koshewnikovi) in contrast to 10 in C. gratzianowi sp. nov. As to the Northern Dvina, a geographically close drainage in the White Sea basin, only five specimens were available for the examination including three old specimens in poor condition. The morphometric characters, fin-ray, lateral-line, and vertebral counts indicate to their probable conspecificity with the Pechora species we tentatively identify as C. koshewnikovi, but one specimen had branched pectoral-fin rays. Discriminant Function Analysis (DFA) of morphometric characters was performed for 53 examined specimens (as in Table 1): 9 specimens of C. gratzianowi sp. nov. (holotype and 8 paratypes), 21 specimens including syntypes of C. koshewnikowi (Volga River drainage), 5 specimens of C. koshewnikowi from the Northern Dvina, and 18 specimens from the Pechora. The DFA using morphometric measurements revealed significant morphological shape differences between the new species and the other samples (Fig. 7, Table 5). This analysis correctly classified all individuals of the new species, C. gratzianowi sp. nov., as well as the Volga sculpin (C. koshewnikowi), and the combined sample of individuals from the Northern Dvina and the Pechora tentatively identified as C. koshewnikowi. Statistics values are as follows: Wilks’ Lambda 0.00121, approx. F (69, 81) = 9.9956, p<0.0000, which indicate almost perfect discrimination. Cottus gratzianowi sp. nov. from the Onega River drainage is the most distant from the Volga sculpin (Squared Mahalanobis Distance equal 116.5); the Pechora and the Northern Dvina samples are closer (72.4 and 96.1, respectively) but still significantly distant. The most removed, by the morphometric characters considered, are the Volga and the Northern Dvina samples (224.6) and the Volga and the Pechora (167.4). For all mentioned comparisons, p<0.0000. Partial Lambdas, demonstrating the unique contribution of the respective variable to the discriminatory power of the whole model, are given in Table 5. The most significant (Partial Lambda <0.7) for discrimination of the samples under consideration are length of caudal peduncle, head depth, snout length, head width, length of gill slit, and horizontal eye diameter. Thus, the Pechora and the Northern Dvina combined sample is well discriminated by a complex of morphometric characters from both C. koshewnikowi from the Volga and C. gratzianowi sp. nov. A further study of these sculpins is needed. Comparative material. Cottus koshewnikowi. Caspian Sea basin: Syntypes: ZMMU Р- 2001 (4, SL 47–53 mm), Goredva River at village of Ligachevo; ZMMU Р- 2658 (20, SL 44–76 mm), same locality; ZMMU P- 2688 (3, SL 46−71 mm), same locality; ZMMU Р- 3118 (1, SL 56 mm), same locality. Non-type material: ZMMU Р- 3912 (1, SL 40 mm) Seliger Lake; ZIN 15540 (10, SL 45-84 mm), Kos’va River (left tributary of Kama); ZIN 15777 (4, SL 62−78 mm) Kama River at village of Ust-Divia; ZIN 55581 (60, SL 51–98 mm), Kama River at town of Perm'; ZIN 55582 (11, SL 39–66 mm), Oka River at town of Kaluga; ZIN 55583 (29, SL 48.5–95 mm), Kara River (Kama system); ZIN 55685 (5, SL 45−97 mm), Kolosleyka River, Kama River system. Baltic Sea basin: ZIN 8568 (5, SL 60.8–72.8 mm) Neva River at St Petersburg; ZIN 1909 (4, SL 54.7 –68.0 mm) Neva River; ZIN 3718 (1, SL 34.5–56.5 mm), Neva River; ZIN 14439 (5, SL 57.8 –82.0 mm) Neva River, Ostrovki; ZIN 14493 (2, SL 60.8 –100.0 mm), same locality; ZIN 23480 (5, SL 19.5–30.5 mm) Neva River downstream of Mga River mouth; ZIN 36171 (3, SL 37.0– 51 mm), Neva River at St Petersburg; ZIN 40739 (2, SL 40.5 –41.0 mm), Ladoga Lake; ZIN 41251 (2, SL 61.0–73.0 mm), Neva River at Ostrovky; ZIN 41253 (2, SL 67.5– 69.5 mm), Neva River at St Petersburg; ZIN 51904 (6, SL 41.0– 51.5 mm), Ladoga Lake, 5 кm from Kraskovo, depth 4.5 m; ZIN 52249 (1, SL 78.0 mm), Lute River at Sikovitsy, Pskov Province; ZIN 52861 (2, SL 40.0–52.0 mm), Ladoga Lake; ZIN 54243 (5, SL 66.2 –73.0 mm), Neva River delta; ZIN 54247 (1, SL 71.0 mm), Neva River, depth 15–20 m; ZIN 55686 (75, SL 48.0– 57.5 mm), Izhora River at town of Gatchina. Barentz Sea basin: ZIN 11331 (7, SL 57.2–88.5 mm), Pechora River; ZIN 37102 (2, SL 52.0–58.0 mm), upper Pechora River, 62 о N, 58 о 44 ’E; ZIN 41252 (1, SL 70 mm), Pechora River; ZIN 50221 (3, SL 77−79 mm), Ydzhyd- Lyaga River, tributary of Ilych, Pechora drainage; ZIN 55687 (6, SL 63−74 mm), Koshym River, tributary of Pechora River. White Sea basin: ZIN 41256 (1, SL 77.0 mm), Northern Dvina River at town of Arkhangelsk; ZIN 52124 (2, SL 75, 74.6), Yavzora River, tributary of Pinega, Northern Dvina drainage; ZIN 55688 (2, SL 63, 71 mm), Dvinitsa River, Northern Dvina river system. Cottus gobio. ZIN 13510 (1, SL 58.5 mm), Sillamae; ZIN 41255 (1, SL 62.0 mm), Baltic Sea, Svybiriken Bay, Aland Islands: Gradeso. Cottus poecilopus. Syntypes: NMW 78816 (1, SL 84.5 mm) Ober-Ungarn, Karpaten; NMW 78816 (2, SL 88, 92 mm) same locality; NMW 6729 (3, SL 82−92 mm); non type: ZIN 315 (1, 90 mm), Vistula River, ZIN 37661 (1, SL 66 mm), Teresva River, Danube drainage, Ukraine. Cottus metae. NMW (3, SL 75−79 mm), Krupa River, Sava system, Danube.Published as part of Sideleva, Valentina G., Naseka, Alexander M. & Zhidkov, Zakhar V., 2015, A new species of Cottus from the Onega River drainage, White Sea basin (Actinopterygii: Scorpaeniformes: Cottidae), pp. 419-430 in Zootaxa 3949 (3) on pages 420-430, DOI: 10.11646/zootaxa.3949.3.7, http://zenodo.org/record/24367
Electronic and Nuclear Subsystem Response in Hybrid Halide Perovskites Under γ-Irradiation
No full textLead halide perovskites, including single-cation (MAPbI3, FAPbI3, CsPbI3) and mixed-cation (Cs0.12FA0.88PbI3, Cs0.1MA0.15FA0.75PbI3) compositions, are promising for both space photovoltaics and γ-ray detection due to their tunable optoelectronic properties. However, their response to high-energy radiation remains critical for reliable operation. We performed Monte-Carlo simulations using GEANT4 to investigate photon interactions (0.1–90 MeV) with perovskites of varying composition and thickness (1 cm to 1 μm). Results indicate that heavy atoms (Pb, I) dominate photoelectric absorption and scattering, broadly similar absorbed energies and event rates across compositions. Cs-containing perovskites exhibit slightly higher absorption and ionization, whereas FA- and MA-rich compositions show reduced photoelectric and Rayleigh scattering. Layer thickness strongly influences the radiation response: ultrathin films display fewer interactions with higher per-event energy, while millimeter-scale layers achieve efficient absorption and enable pair-production events at MeV energies. The sequence of dominant processes follows the expected energy dependence: photoelectric effect at low energies, Compton and Rayleigh scattering at intermediate energies, and pair production at high energies. These findings demonstrate that perovskite γ-interaction is primarily governed by heavy-atom content, with A-site cations fine-tuning the process balance, and that device performance for detection or photovoltaics depends critically on layer thickness
Modification of titanium and titanium dioxide surfaces by ion implantation: Combined XPS and DFT study
No full textThe results of XPS measurements (core levels and valence bands) of P+, Ca+, P+Ca+ and Ca+P+ ion implanted (E=30 keV, D=1×1017cm-2) commercially pure titanium (cp-Ti) and first-principles density functional theory (DFT) calculations demonstrates formation of various structural defects in titanium dioxide films formed on the surface of implanted materials. We have found that for double implantation (Ti:P+,Ca+ and Ti:Ca+,P+) the outermost surface layer is formed mainly by Ca and P, respectively, i.e. the implantation sequence is very important. The DFT calculations show that under P+ and Ca+P+ ion implantation the formation energies for both cation (P-Ti) and anion (P-O) substitutions are comparable, which can induce the creation of [PO4]3- and Ti-P species. For Ca+ and P+Ca+ ion implantation the calculated formation energies correspond to Ca2+-Ti4+ cation substitution. This conclusion is in agreement with XPS Ca 2p and Ti 2p core levels and valence-band measurements and DFT calculations of the electronic structure of related compounds. The conversion of implanted ions to Ca2+ and [PO4]3- species provides a good biocompatibility of cp-Ti for further formation of hydroxyapatite. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Cu–CeO2 nanocomposites: mechanochemical synthesis, physico-chemical properties, CO-PROX activity
No full textCatalytic systems designated for preferential oxidation of CO in the presence of H2 are prepared by ball milling of Cu and CeO2, a simple and cheap one-step process to synthesize such catalysts. It is found that after 60 min of milling, a mixture of 8 wt.% Cu–CeO2 powders exhibits CO conversion of 96% and CO selectivity of about 65% at 438 K. Two active oxygen states, which are not observed in case of pure CeO2, were detected in the nanocomposite lattice and attributed to the presence of Cu in surface sites as well as in subsurface bulk sites. Correspondingly, oxidation of CO to CO2 was found to occur in a two-stage process with Tmax ≈ 395/460 K, and oxidation of H2 to H2O likewise in a two-stage process with Tmax ≈ 465/490 K. The milled powder consists of CeO2 crystallites sized 8–10 nm agglomerated to somewhat larger aggregates, with Cu dispersed on the surface of the CeO2 crystallites, and to a lesser extent present as Cu2O. [Figure not available: see fulltext.] © 2016, Springer Science+Business Media Dordrecht
Cu-Site Disorder in CuAl2O4 as Studied by XPS Spectroscopy
No full textThe results of full study of X-ray photoelectron spectra (XPS) of spin-liquid candidate CuAl2O4 including the measurements of high-energy resolved core level (Cu 2p, Al 3p, O 1s), Cu LMM Auger and valence band spectra are presented. The comparison of obtained results with spectra of reference samples and specially performed density functional theory calculations has confirmed a finite Cu site-disorder in CuAl2O4, where about 30% of Cu2+ ions occupy the octahedral sites. Obtained valence band spectra can be used in further theoretical studies aimed on the investigation of electronic and magnetic properties of this mysterious ma-terial. © 2021, The Author(s).The DFT calculations were supported by the Russian Science Foundation (project no. 20-62-46047). The XPS measurements were supported by the Ministry of Science and Higher Education of the Russian Federation (theme Electron no. AAAA-A18-118020190098-5 and project FEUZ 2020-0060). I.S. Zhidkov acknowledges the support of the Council of the President of the Russian Federation for State Support of Young Scientists and Leading Scientific Schools (project no. MK-989.2020.2)
CuO-CeO2 nanocomposite catalysts produced by mechanochemical synthesis
No full textMechanochemical synthesis based on ball-milling of individual oxides was applied as a one-step preparation technique for CuO-CeO2 catalyst for preferential CO oxidation in H2 excess. The mechanical energy dose transferred to the original powder mixture determines both the catalyst composition and activity. It is found that after 90 min of milling (corresponding to a dose of 372 kJ mol-1), a mixture of 10 wt.% CuO-CeO2 powder exhibits a CO conversion of 97% at 423 K. Four active oxygen states, which are not observed in case of pure CeO2, were detected in the nanocomposite lattice and attributed to the presence of Cu in surface sites as well as in subsurface bulk sites of CeO2, in nearest neighbor and next nearest neighbor positions. Correspondingly, oxidation of CO to CO2 was found to occur in a two-stage process with Tmax = 395/460 K, and oxidation of H2 to H2O likewise in a four-stage process with Tmax = 426/448/468/516 K. The milled powder consists of CeO2 crystallites sized 8-10 nm agglomerated to somewhat larger aggregates, with CuO dispersed on the surface of the CeO2 crystallites, and to a lesser extent present as Cu2O. © 2019 Author(s).This work was partially supported by Russian Foundation for Basic Research [Projects n.n. 16-03-00330a and 16-03-00178a] in theoretical studies and part of experimental research and by FASO [program no. AAAA-A18-118012390374-3]. XPS measurements were supported by FASO (Theme “Electron”). The Alexander von Humboldt foundation is gratefully acknowledged for funding. We also would like to thank N. Berezkina for SEM measurements. We acknowledge support by the Open Access Publication Funds of the Göttingen University. Declarations of interest: none
Synthesis Conditions and Properties of SiAlCN Coatings Obtained by Reactive Evaporation of Al in a Hollow Cathode Arc Discharge in Hexamethyldisilazane Vapors
No full textSiAlCN coatings were first obtained by the method of reactive evaporation of aluminum and plasma chemical activation of an organosilicon precursor in a hollow cathode arc discharge. The spectrum of discharge plasma was studied by optical emission spectroscopy under conditions of evaporation of Al in an Ar+N2+hexamethyldisilazane vapor/gas medium, and it was shown that in the presence of a metal component in the plasma, not only did intensive activation of various components of the media occur but also an increased ionic effect on the surface of the coating was provided, with a deposition rate of up to 10.1 µm/h. The films had a dense and homogeneous structure and had a hardness of up to 31 GPa and good adhesion on stainless steel. The results of SEM, FTIR, and XRD showed that their structure was a nanocomposite consisting of an amorphous matrix based on SiCN and AlN with inclusions of AlCN nanocrystals
Dataset of SCAPS-1D simulated halide perovskite solar cells with SHAP and machine learning-based PCE optimizationZenodo
No full textThis data article describes a dataset generated by using SCAPS-1D simulation software to capture photovoltaic performance metrics for perovskite solar cells (PSC). The data collection process involved systematically modeling a range of device configurations by varying perovskite compositions, layer thicknesses, and combinations of charge transport layers. Key parameters such as open-circuit voltage, short-circuit current density, fill factor, and power conversion efficiency were recorded, with simulation outputs provided in Excel files. Additional files include detailed material databases featuring physical properties of electron and hole transport layers—such as band gap energies, electron affinities, dielectric permittivity, and carrier mobilities—organized in separate spreadsheets.Moreover, the repository offers a pre-trained CatBoost machine learning to predict the solar cell efficiency, along with a Jupyter Notebook that outlines the data preprocessing, machine learning workflow, and feature importance analysis via SHAP values. The structured dataset supports a reproducible simulation environment and is designed to facilitate further research in computational materials science and renewable energy. Its comprehensive organization makes it suitable for applications including photovoltaic device optimization, evaluation of simulation-based predictive approaches, and development of advanced data-driven models. Publicly hosted on Zenodo, this dataset provides an accessible resource for researchers and practitioners aiming to explore and enhance perovskite solar cell configurations through computational analysis and machine learning techniques
Synthesis of Nanocomposite TiSiCN Coatings by Titanium Evaporation and Organosilicon Compound Activation in Hollow Cathode Arc Discharge
No full textTiSiCN coatings have been obtained by anode evaporation of titanium and the decomposition of hexamethyldisilazane in an arc discharge, using a self-heated hollow cathode, at the pressure rate of 1 mTorr of the Ar+N2 gas mixture. The proposed method makes it possible to independently and widely change the amount of metal and precursor vapor flows, the pressure and composition of the vapor-gas mixture and the degree of ionic interaction on the surface of the growing coating within a single discharge system. The paper presents the method and the results of the effect of a current discharge (10–50 A), and the flux of precursor vapours (0–1 g/h), on deposition rates, compositions, and properties of TiSiCN coatings deposited by an advanced combined PVD+PECVD method. Dense homogeneous TiSiCN coatings up to 6 µm thick and up to 27.5 GPa in hardness were obtained at 7.5 µm/h. The composition of the obtained coatings has been studied by X-ray diffraction and X-ray photoelectron spectroscopy, and it has been shown that the presented methods can form nanocomposite coatings with nanocrystallites TiC, TiN, and TiCxN1−x 3–10 nm in the amorphous matrix based on SiCN
Kinetics of Iron Collector Leaching in HCl and HF Media
No full textAutomotive catalysts containing Platinum Group Metals (PGMs) are valuable secondary raw materials for refineries. Hydrometallurgical processing of catalysts is ineffective due to the low PGMs content—0.15–0.3%. Therefore, such raw materials are melted into an iron collector containing 1.5–5% PGMs. However, when leaching a collector containing 10–20% Si in both HCl and H2SO4, the recovery of PGMs does not exceed 40%. The latter indicates incomplete destroying of the PGM-encapsulating ferrosilicon matrix. To completely destroy the ferrosilicon matrix, it is proposed to carry out the leaching process in a mixture of HCl and HF. In this case, the extraction of Fe into solution and Si into the gas phase (in the form of SiF4) exceeds 90%. This should be sufficient to completely destroy the ferrosilicon matrix and release PGMs. The current work presents the results of studies of the leaching kinetics of the iron collector containing ferrosilicon in a mixture of HCl and HF using the Shrinking Core Model (SCM). It was found that the greatest positive effect on Fe extraction into solution is exerted by HCl concentration and temperature, while Si release into the gas phase is only influenced by HF concentration. In addition, during the destroying of ferrosilicon, FeF2 is formed and deposited on the surface of the material in the form of thin-film conglomerates. This leads to diffusion difficulties and a gradual decrease in the intensity of the iron collector leaching 30 min after the start of process. After 120 min, there may be a decrease in Fe recovery into solution
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