Crystallography Reports最新文献

{"title":"Features of Interlayer Interfaces in Transparent Conducting Oxide/Metal/Oxide Trilayer Structures","authors":"A. Sh. Asvarov,&nbsp;A. K. Akhmedov,&nbsp;E. K. Murliev,&nbsp;A. Kh. Abduev,&nbsp;V. M. Kanevsky","doi":"10.1134/S1063774524602004","DOIUrl":"10.1134/S1063774524602004","url":null,"abstract":"<p>A comparative study of the growth processes, microstructures, and electrical characteristics of oxide/metal/oxide trilayer structures of different compositions synthesized at 50°C by rf magnetron sputtering in argon has been performed. The effect of subsequent annealing in an open atmosphere on the conductivity of the structures has been investigated. Transmission electron microscopy and energy-dispersive X-ray spectroscopy have been used to examine changes in the microstructure and profiles of distribution of chemical elements included in the structures under annealing. Based on the results obtained, mechanisms have been proposed for the transformation of interlayer interfaces and conditions of carrier transport in the structures, depending on the composition of the oxide and metallic layers comprising them.</p>","PeriodicalId":527,"journal":{"name":"Crystallography Reports","volume":"69 7","pages":"1144 - 1149"},"PeriodicalIF":0.6,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143423381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impurity and γ-Stimulated Effect of Increasing the Transparency of CaF2 Crystals in the Fundamental Edge Region","authors":"S. E. Sarkisov,&nbsp;V. A. Yusim,&nbsp;Yu. V. Pisarevsky","doi":"10.1134/S1063774524601874","DOIUrl":"10.1134/S1063774524601874","url":null,"abstract":"<p>A comparison of absorption spectra revealed activator rare-earth ions at which the effect of impurity and radiation-induced decrease in the optical density at a wavelength of the short-wavelength edge of CaF₂ was observed; this effect is explained by the shift of the interband absorption of the crystal to the spectral vacuum UV region. Experiments showed that a multiple increase in the transparency of CaF₂ in the wavelength range of 190–200 nm occurs when doping crystals with ions of europium and ytterbium—elements having the lowest chemical potentials in the lanthanide series. This feature determines the ability of Eu³⁺ and Yb³⁺ to charge conversion of the oxidation state (+3 → +2). The absorption spectra of these ions were compared with the spectra of Nd³⁺ and Er³⁺ ions, which do not exhibit any changes in charge upon γ irradiation of CaF₂ crystals and have chemical potentials comparable in magnitude with those of other elements of the series, for which this parameter is 2–5 times larger than for Eu and Yb. The spectral features of the absorption of gadolinium ions were additionally investigated in a simple CaF₂ : 2 mol % GdF₃ crystal and a solid solution based on CaF₂ with addition of 10 mol % GdF₃ with the empirical formula Ca_0.9Gd_0.1F_2.1. A peculiarity of Gd is that, in contrast to other rare-earth elements, its ground energy 4<i>f</i> levels in the tri- and divalent states are located, respectively, on the top of the valence band and above the bottom of the conduction band. CaF₂ : 0.1 mol % Eu²⁺ crystals are proposed as an optical medium almost completely transparent in the wavelength range of 190–200 nm. The revealed effect is of interest for designing optical materials for systems of near-Earth and space monitoring for environmental and military purposes, as well as for the production of lenses applied in UV microphotolithography systems.</p>","PeriodicalId":527,"journal":{"name":"Crystallography Reports","volume":"69 7","pages":"1121 - 1130"},"PeriodicalIF":0.6,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143423025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Protein of Unknown Function from Bacterium Variovorax paradoxus with the Amino Acid Substitution N174k Capable of Forming Schiff Base with a PLP Molecule","authors":"I. O. Ilyasov,&nbsp;M. E. Minyaev,&nbsp;T. V. Rakitina,&nbsp;A. K. Bakunova,&nbsp;V. O. Popov,&nbsp;E. Yu. Bezsudnova,&nbsp;K. M. Boyko","doi":"10.1134/S1063774524602235","DOIUrl":"10.1134/S1063774524602235","url":null,"abstract":"<p>Pyridoxal 5'-phosphate (PLP)-dependent enzymes are among the most abundant enzymes present in nearly all organisms, where they perform more than 150 different catalytic functions. Based on the three-dimensional structures, these enzymes are classified into seven (I–VII) different fold types. In these enzymes, the cofactor is bound as a Schiff base with the conserved active-site lysine residue. Recently, we have discovered the protein from the bacterium <i>Variovorax paradoxus</i> (VAPA), which belongs to the fold type IV and has a significant structural similarity to transaminases. It contains an asparagine residue at the position of catalytic lysine in fold type IV transaminases and, consequently, it cannot form a Schiff base with PLP and does not have aminotransferase activity. In this study, a single-point mutant of the VAPA protein with the N174K substitution was obtained and its three-dimensional structure was determined. An analysis of the obtained data showed that the introduced mutation restores the ability of  VAPA to form a Schiff base with the cofactor.</p>","PeriodicalId":527,"journal":{"name":"Crystallography Reports","volume":"69 6","pages":"861 - 865"},"PeriodicalIF":0.6,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143423463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Plasmon Polaritons of the TE and TM Types in a Metal Film Bordering a Superlattice. I: Properties of Impedances of Semi-Infinite Media and Films","authors":"A. N. Darinskii","doi":"10.1134/S1063774524602338","DOIUrl":"10.1134/S1063774524602338","url":null,"abstract":"<p>The <i>TE-</i> and <i>TM</i>-polarized surface plasmon polaritons in a metal film placed between a periodic superlattice and a homogeneous dielectric or between two periodic superlattices have been theoretically investigated. Dispersion equations are derived in the form of the equality to zero of the determinant of a real symmetric matrix composed of the surface impedances of the media and film. Some general properties of the impedances and eigenvalues of the matrices entering the dispersion equations are established.</p>","PeriodicalId":527,"journal":{"name":"Crystallography Reports","volume":"69 6","pages":"905 - 915"},"PeriodicalIF":0.6,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143423319","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimization of the Composition of Solid Electrolytes in MF2−LaF3−NdF3 and MF2−CeF3−PrF3 (M = Ca, Sr, Ba) Systems by Room-Temperature Ionic Conductivity","authors":"N. I. Sorokin,&nbsp;D. N. Karimov","doi":"10.1134/S1063774524602144","DOIUrl":"10.1134/S1063774524602144","url":null,"abstract":"<p>In order to search for new highly conductive fluoride materials, X-ray diffraction and conductometric properties of alloys (polycrystals) of the compositions 38LaF₃^<b>.</b>57NdF₃^<b>.</b>5<i>M</i>F₂ and 47.5CeF₃^<b>.</b>47.5PrF₃^<b>.</b>5<i>M</i>F₂ (mol %) for <i>M</i> = Ca, Sr, and Ba were studied. The samples were prepared by spontaneous crystallization of homogenized melts in the <i>M</i>F₂−LaF₃−NdF₃ and <i>M</i>F₂−CeF₃−PrF₃ systems in a fluorinating atmosphere. The resulting alloys are solid solutions of the compositions (La_0.4Nd_0.6)_0.95<i>M</i>_0.05F_2.95 and (Ce_0.5Pr_0.5)_0.95<i>M</i>_0.05F_2.95 with a tysonite-type structure (sp. gr. <span>(Pbar {3}c1)</span>). The ion-conductive properties of three-component (<i>R</i>,<i>R</i>')_0.95<i>M</i>_0.05F_2.95 (<i>R</i>, <i>R</i>' = 0.4La + 0.6Nd and 0.5Ce + 0.5Pr) and two-component <i>R</i>_0.95<i>M</i>_0.95F_2.95 (<i>R</i> = La, Ce, Pr, Nd) compositions were carried out. It was found that, in the case of (Ce_0.5Pr_0.5)_0.95Sr_0.05F_2.95 polycrystals, the interior grain conductivity, equal to σ_293 K = 1.3 × 10⁻³ S/cm at room temperature, significantly exceeds the ionic conductivity of bulk Ce_0.95Sr_0.05F_2.95 and Pr_0.95Sr_0.05F_2.95 solid solution crystals, which confirms the influence of the geometric factor on the magnitude of ionic conductivity in the families of crystals with a tysonite-type structure. The study shows the prospects of further comprehensive research of three-component compositions (<i>R</i>,<i>R</i>')_0.95<i>M</i>_0.05F_2.95 to achieve the limit value of room-temperature conductivity.</p>","PeriodicalId":527,"journal":{"name":"Crystallography Reports","volume":"69 6","pages":"924 - 930"},"PeriodicalIF":0.6,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143423322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structure of T5-Like Phage dUTPase from Vibrio Phage Phi3","authors":"A. S. Glukhov,&nbsp;U. F. Dzhus,&nbsp;I. A. Kolyadenko,&nbsp;G. K. Selikhanov,&nbsp;A. G. Gabdulkhakov","doi":"10.1134/S1063774524602041","DOIUrl":"10.1134/S1063774524602041","url":null,"abstract":"<p>The first crystal structure of dUTPase from the bacteriophage <i>Vibrio</i> phage phi3 was determined at 1.95 Å resolution. This protein has a homotrimeric quaternary structure characteristic of this type of dUTPases and contains a short loop in the N-terminal region of the polypeptide chain, which is specific for Т5-like bacteriophage dUTPases. It was demonstrated that, despite a low amino acid sequence homology between phage (Т5 and phi3) dUTPases, phi3 dUTPase can effectively replace phage Т5 dUTPase during the lytic cycle.</p>","PeriodicalId":527,"journal":{"name":"Crystallography Reports","volume":"69 7","pages":"1093 - 1099"},"PeriodicalIF":0.6,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143423361","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Preparation and Study of the Crystal Structure of a Complex Compound Based on Cobalt, 1,5-Disulfonaphthalene, and Ethylenediamine","authors":"Zh. R. Suyunov,&nbsp;Kh. Kh. Turaev,&nbsp;Sh. A. Kasimov,&nbsp;N. A. Ermuratova,&nbsp;K. N. Kornilov","doi":"10.1134/S1063774524602053","DOIUrl":"10.1134/S1063774524602053","url":null,"abstract":"<p>A complex compound based on a divalent cobalt ion as a complexing agent and two different ligands, 1,5-disulfonaphthalene (1,5-naphthalenedisulfonic acid, Na₂NDS) and ethylenediamine, has been synthesized for the first time. The structure of the metal complex was investigated by IR and Raman spectroscopy. It was proved that the compound has a stoichiometric composition [Co(NO₃)⋅(C₂H₄(NH₂)₂)₂]<span>(_{2}^{ + })</span>⋅(C₁₀H₆O₆S₂)^2–⋅4H₂O. The complex was subjected to thermal analysis to determine its stability. Its stability, determined by the existence of intramolecular hydrogen bonds, was confirmed. Molecular rearrangements occur in the structure at 142°C, and gradual decomposition of the compound begins; in the range of 305–311°C the material studied undergoes melting, and complete destruction occurs only at 500°C. The crystal structure of the obtained metal complex was studied by X-ray diffraction analysis. A Hirshfeld surface analysis revealed intermolecular interactions between hydrogen and oxygen atoms and between hydrogen and nitrogen atoms, i.e., hydrogen bonds, stabilizing the complex.</p>","PeriodicalId":527,"journal":{"name":"Crystallography Reports","volume":"69 7","pages":"1077 - 1086"},"PeriodicalIF":0.6,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143423376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Different Gaseous Media in the Process of Microwave Pyrolysis Carbonization of Cellulose on the Properties of the Obtained Activated Carbon","authors":"I. G. Dyachkova,&nbsp;D. A. Zolotov,&nbsp;A. S. Kumskov,&nbsp;I. S. Volchkov,&nbsp;E. V. Matveev,&nbsp;V. V. Berestov,&nbsp;V. E. Asadchikov","doi":"10.1134/S1063774524601977","DOIUrl":"10.1134/S1063774524601977","url":null,"abstract":"<p>Comparative studies of the characteristics of high-molecular organic matter (cotton lint), subjected to pyrolytic carbonization under conditions of high-intensity microwave radiation in various gaseous media (N₂, CO₂, Ar), have been carried out. The following methods were applied: determination of the adsorption activity by methylene blue indicator, X-ray fluorescence analysis, transmission electron microscopy with microanalysis, and X-ray phase analysis. Electrodes were fabricated from carbon materials obtained by microwave carbonization using different gases, and symmetric cells were assembled according to the two-electrode scheme. Their electrochemical properties were investigated using cyclic voltammetry and galvanostatic charge–discharge methods. The materials obtained using a CO₂ gaseous medium were found to possess the best characteristics.</p>","PeriodicalId":527,"journal":{"name":"Crystallography Reports","volume":"69 6","pages":"838 - 850"},"PeriodicalIF":0.6,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143423465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of γ Irradiation on the Optical and Energy Spectra of Fluoride Single- and Multicomponent Crystal Systems Activated by Cе3+ Ions","authors":"S. E. Sarkisov,&nbsp;V. A. Yusim,&nbsp;Yu. V. Pisarevsky","doi":"10.1134/S1063774524601862","DOIUrl":"10.1134/S1063774524601862","url":null,"abstract":"<p>The scintillation properties of LiF crystals and the family of multicomponent compounds LiF–<i>R</i>F₃ (<i>R</i> = Y, Gd), activated by Ce³⁺ ions, proposed as materials sensitive to thermal neutrons and γ radiation, are compared. An abnormally large cross section of radiative capture of thermal neutrons in gadolinium and the calculated high values of the effective charge number <i>Z</i> of multicomponent compounds determine their efficiency as neutron and gamma scintillators in comparison with LiF. The absorption spectra of unirradiated and γ-irradiated LiF crystals activated by cerium ions are analyzed. The bands of induced color centers are identified. The conversion of the ion oxidation state, Ce⁴⁺ → Ce³⁺, related to effect of γ quanta on the crystals, is investigated. The light yield of all crystals studied was determined by comparing the positions of the maxima of total absorption peaks with the position of the maximum of the total absorption peak of a standard NaI(Tl) sample in the energy spectra from a ¹³⁷Cs γ source with an energy of 662 keV. The effect of increasing the light yield under γ irradiation of LiF crystals with Ce³⁺ ions was discovered and explained in terms of the participation of γ-induced color centers (<i>F</i> and <i>F</i>^<i>-</i> centers). The possibility of increasing additionally the light efficiency due to sensitized luminescence in LiGdF₄ : Ce³⁺ crystals was analyzed.</p>","PeriodicalId":527,"journal":{"name":"Crystallography Reports","volume":"69 7","pages":"1131 - 1137"},"PeriodicalIF":0.6,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143423026","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microhardness of Metal–Polymer Composites Based on Polymer Track Membranes and FeNi Nanowires","authors":"I. M. Doludenko,&nbsp;I. S. Volchkov,&nbsp;P. L. Podkur,&nbsp;I. O. Koshelev,&nbsp;D. R. Khairetdinova,&nbsp;V. M. Kanevskii","doi":"10.1134/S1063774524601576","DOIUrl":"10.1134/S1063774524601576","url":null,"abstract":"<p>Metal–polymer composites have been obtained by matrix synthesis in pores of track membranes with different times of filling pores with permalloy. The geometric parameters of the resulting arrays of nanowires, which were the functional filling of composites, were determined using scanning electron microscopy. The microhardness of the nanocomposites was studied by the nanoindentation method. A relationship between the increase in the microhardness of the metal–polymer composite and the degree of filling the matrix is established. It is suggested that there is a relationship between the composite hardness and the number of intersections of nanowires in the matrix.</p>","PeriodicalId":527,"journal":{"name":"Crystallography Reports","volume":"69 7","pages":"1150 - 1156"},"PeriodicalIF":0.6,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143423382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}