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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Аверьянов, Евгений Михайлович
Заглавие : Плотность поляризуемости и ориентационный порядок молекул (мономеров) в одноосной молекулярной (полимерной) пленке
Колич.характеристики :10 с
Место публикации : Жидк. крист. и их практич. использ. - 2024. - Т. 24, № 2. - С. 54-63. - ISSN 19913966 (ISSN), DOI 10.18083/LCAppl.2024.2.54; Liq. Cryst. Appl. - ISSN 24999644 (eISSN)
Примечания : Библиогр.: 14
Аннотация: Для адекватных представлений о природе спектральных и оптических свойств одноосных молекулярных (полимерных) пленок необходимы данные об энергетической структуре молекул (мономерных звеньев полимерной цепи – мономеров) и дальнем ориентационном порядке дипольных моментов mq электронных/колебательных переходов. Этот порядок характеризуется параметрами порядка Uq моментов mq относительно оптической оси n пленки. До сих пор опосредованными источниками таких данных служили компоненты nj(ω), kj(ω) показателей преломления Nj(ω) = nj(ω) – ikj(ω) или компоненты ε(1,2)j(ω) диэлектрических проницаемостей εj(ω) = ε1j(ω) – iε2j(ω) пленки для поляризаций световой волны вдоль (j = ||) и нормально (j = ⊥) оси n. Непосредственная информация об энергетической структуре молекул (мономеров) и параметрах Uq содержится в компонентах γ(1,2)j(ω) средних по ансамблю поляризуемостей γj(ω) = γ1j(ω) – iγ2j(ω) молекул (мономеров). В настоящей работе для получения этой информации используются компоненты P(1,2)j(ω) плотностей поляризуемости Pj(ω) = [εj(ω) – 1]/fj(ω) = 4pNγj(ω) = P1j(ω) – iP2j(ω). Здесь fj(ω) = 1 + Lj[εj(ω) – 1] – компоненты тензора локального поля световой волны в пленке; компоненты тензора Лорентца Lj определяются с использованием зависимостей nj(ω) в области прозрачности пленки; N – число молекул (мономеров) в единице объема пленки. Развиты методы определения параметров Uq для молекулярных переходов с использованием зависимостей P(1,2)j(ω) в пределах изолированных полос поглощения, отвечающих данным переходам. Эти методы подтверждены для одноосных пленок сопряженного полимера F8BT с преимущественной ориентацией макромолекул в плоскости пленки XY, оптической осью n||Z и известными зависимостями nj(ω), kj(ω) в областях прозрачности и низкочастотного электронного поглощения. Установлены спектрально-инвариантные соотношения, связывающие функции P(1,2)j(ω) и ε(1,2)j(ω).In order to gain an adequate understanding about the nature of spectral and optical properties of uniaxial molecular (polymer) films, the data about the energy structure of molecules (monomers) and the long-range orientation order of dipole moments mq of electronic/vibrational transitions are needed. This order is characterized by the order parameters Uq of moments mq with respect to the optical axis n of the film. Until now, components nj(ω), kj(ω) of refractive indices Nj(ω) = nj(ω) – ikj(ω) or components ε(1,2)j(ω) of dielectric constants εj(ω) = ε1j(ω) – iε2j(ω) of the film for the light-wave polarizations along (j = ||) and across (j = ⊥) the axis n had been used as indirect sources of such data. The direct information about the energy structure of molecules (monomers) and parameters Uq is contained in the components γ(1,2)j(ω) of ensemble-averaged polarizabilities γj(ω) = γ1j(ω) – iγ2j(ω) of molecules (monomers). In this work, components P(1,2)j(ω) of polarizabilities densities Pj(ω) = [εj(ω) – 1]/fj(ω) = 4pNγj(ω) = P1j(ω) – iP2j(ω) are used for receiving such information. Here, fj(ω) = 1 + Lj[εj(ω) – 1] are the local-field tensor components for the light wave in the film; the Lorentz-tensor components Lj are obtained using the dependences nj(ω) in the transparency region of the film; N is the number of molecules (monomers) per unit volume of the film. Methods for determining parameters Uq for molecular transitions were developed using the dependences P(1,2)j(ω) within the isolated absorption bands corresponding to the transitions. The methods were confirmed for the uniaxial films of the conjugated polymer F8BT with the preferred orientation of macromolecules in the film plane XY with the optical axis n||Z and the known dependences nj(ω), kj(ω) in the transparency and low-frequency electronic absorption ranges. The spectral-invariant correlations connecting functions P(1,2)j(ω) and ε(1,2)j(ω) were established.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Stepin E. A., Sushko E. S., Vnukova N. G., Churilov G. N., Rogova A. V., Tomilin F. N., Kudryasheva N. S.
Заглавие : Effects of endohedral Gd-containing fullerenols with a different number of oxygen substituents on bacterial bioluminescence
Колич.характеристики :19 с
Место публикации : Int. J. Mol. Sci. - 2024. - Vol. 25, Is. 2. - Ст.708. - ISSN 16616596 (ISSN), DOI 10.3390/ijms25020708. - ISSN 14220067 (eISSN)
Примечания : Cited References: 102. - This research was funded by the State Assignment of the Ministry of Science and Higher Education of the Russian Federation, project No. 0287-2021-0020, and partly supported by the Russian Science Foundation No. 23-26-10018, Krasnoyarsk Regional Science Foundation
Аннотация: Gadolinium (Gd)-containing fullerenols are perspective agents for magnetic resonance imaging and cancer research. They combine the unique paramagnetic properties of Gd with solubility in water, low toxicity and antiradical activity of fullerenols. We compared the bioeffects of two Gd-containing fullerenols with a different number of oxygen groups—20 and 42: Gd@C82O20H14 and Gd@C82O42H32. The bioluminescent bacteria-based assay was applied to monitor the toxicity of fullerenols, bioluminescence was applied as a signal physiological parameter, and bacterial enzyme-based assay was used to evaluate the fullerenol effects on enzymatic intracellular processes. Chemiluminescence luminol assay was applied to monitor the content of reactive oxygen species (ROS) in bacterial and enzymatic media. It was shown that Gd@C82O42H32 and Gd@C82O20H14 inhibited bacterial bioluminescence at 10?1 and 10?2 gL?1, respectively, revealing a lower toxicity of Gd@C82O42H32. Low-concentration (10?3–10?1 gL?1) bacterial bioluminescence activation by Gd@C82O42H32 was observed, while this activation was not found under exposure to Gd@C82O20H14. Additional carboxyl groups in the structure of Gd@C82O42H32 were determined by infrared spectroscopy and confirmed by quantum chemical calculations. The groups were supposed to endow Gd@C82O42H32 with higher penetration ability through the cellular membrane, activation ability, lower toxicity, balancing of the ROS content in the bacterial suspensions, and lower aggregation in aqueous media.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Platunov M. S., Fedorova N. A., Pyastolova Yu. V., Laptash N. M., Knyazev Yu. V., Tomilin F. N., Dubrovskiy A. A.
Заглавие : Unraveling dynamic Jahn-Teller effect and magnetism in FeTiF6×6H2O single crystal
Колич.характеристики :9 с
Место публикации : J. Alloys Compd. - 2024. - Vol. 999. - Ст.175104. - ISSN 09258388 (ISSN), DOI 10.1016/j.jallcom.2024.175104. - ISSN 18734669 (eISSN)
Примечания : Cited References: 51. - The authors thank the Joint Supercomputer Center (JSCC) of the Russian Academy of Sciences. The authors would like to express their sincere gratitude to the ID12 beamline staff their exceptional dedication and professionalism in performing the synchrotron experiment during the challenging circumstances of the COVID-pandemic. We are particularly grateful to the postdocs, scientists, and technicians who took part in the experiment, ensuring its successful completion. We also gratefully acknowledge the provision of beamtime (Proposal HC-4375) by the European Synchrotron Radiation Facility (ESRF). The access to this world-class facility was instrumental in obtaining the high-quality data that formed the basis of our research. We are deeply appreciative of the contributions of all involved, and we extend our heartfelt thanks to each and every one of them
Аннотация: Hydrated iron fluoridotitanate (FeTiF6 × 6 H2O) single crystals are fascinating magnetic materials with unique properties. To understand the underlying mechanisms, this study combines X-ray absorption near-edge structure (XANES) and X-ray magnetic circular dichroism (XMCD) techniques, complemented by density functional theory (DFT) calculations. Polarization-dependent X-ray absorption spectroscopy, encompassing XANES and XMCD, is a powerful technique for probing the local structures and magnetic properties of materials. It is element-selective, bulk-sensitive, and compatible with a wide range of experimental conditions. In this study, we used XANES and XMCD spectroscopies to investigate the local structures and magnetic properties of Fe and Ti in FeTiF6 × 6 H2O single crystals. XANES analysis revealed distinct local environments around Fe and Ti, providing insights into their coordination environments. Element-selective magnetization measurement at the Fe K-edge demonstrated that iron sites in the oxidation state Fe2+ have an unambiguous paramagnetic contribution to the magnetization along the b-axis. Notably, the absence of an XMCD signal at the Ti K-edge confirmed the absence of a magnetic moment in Ti atoms within the crystal. DFT calculations corroborate the experimental findings and provide insights into the electronic structure and magnetic interactions. The combined results provide a comprehensive understanding of the dynamic Jahn-Teller effect in FeTiF6 × 6 H2O single crystals, highlighting the significance of polarization-dependent X-ray absorption spectroscopy in unraveling the intricate magnetic behavior of such materials. This study contributes to the fundamental understanding of magnetism in these materials and paves the way for the development of novel magnetic materials with tailored properties.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Novikova G. V., Tsyplenkova D. I., Kuzubov A. A., Kolenchukova O. A., Samoilo A. S., Vorobyev S. A.
Заглавие : Complex of ceftriaxone with Mg(II): Synthesis, structure, spectral and antibacterial properties
Колич.характеристики :11 с
Место публикации : J. Sib. Fed. Univ. Chem. - 2023. - Vol. 16, Is. 1. - P.5-15. - ISSN 19982836 (ISSN); Журн. СФУ. Химия. - ISSN 23136049 (eISSN)
Примечания : Cited References: 28. - The research was funded by RFBR, Krasnoyarsk Territory and Krasnoyarsk Regional Fund of Science, project number 20–43–240007
Аннотация: Magnesium complex of ceftriaxone was obtained and characterized by atomic-emission and elemental analysis, TGA, FTIR and Raman spectroscopy, X-ray diffraction and density functional theory calculations. Ceftriaxone was coordinated to the magnesium ion by the oxygen of the triazine cycle in the 6th position, the nitrogen of the amine group of the thiazole ring, and oxygen atoms of the lactam carbonyl and carboxylate groups. The disodium salt of ceftriaxone and magnesium complex were screened for antibacterial activity against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa.Получен и охарактеризован магниевый комплекс цефтриаксона методами атомно-эмиссионного и элементного анализов, ТГА, ИК- и КР‑спектроскопии, РФА и расчетов теории функционала плотности. Цефтриаксон координируется к иону магния через кислород триазинового цикла в шестом положении, азот аминогруппы тиазольного цикла и атомы кислорода карбоксильной и лактамной групп. Динатриевая соль цефтриаксона и комплекс магния были исследованы на антибактериальную активность в отношении Staphylococcus aureus, Escherichia coli и Pseudomonas aeruginosa.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Smirnov, Mikhail, Roginskii, Evgenii, Savin, Aleksandr, Oreshonkov A. S., Pankin, Dmitrii
Заглавие : Density-functional study of the Si/SiO2 interfaces in short-period superlattices: Vibrational states and Raman spectra
Колич.характеристики :18 с
Место публикации : Photonics. - 2023. - Vol. 10, Is. 8. - Ст.902. - ISSN 23046732 (eISSN), DOI 10.3390/photonics10080902
Примечания : Cited References: 61. - The study was supported by grants from the Russian Science Foundation (project No. 22-22-20021) and the Saint-Petersburg Science Center (project No. 32/2022), using the resources of the Computing Center and the Center for Optical and Laser Materials Research at the Research Park of St. Petersburg State UniversityThe study was performed using the resources of the Computing Center and the Center for Optical and Laser Materials Research at the Research Park of St. Petersburg State University. The authors thank Konstantin Smirnov for his valuable advice. The calculations were also performed in part using the facilities of the JSCC supercomputer center at RAS and the Konstantinov computational center at the Ioffe Institute
Аннотация: Raman spectroscopy has proven its effectiveness as a highly informative and sensitive method for the nondestructive analysis of layered nanostructures and their interfaces. However, there is a lack of information concerning the characteristic phonon modes and their activity in Si/SiO2 nanostructures. In order to overcome this problem, the phonon states and Raman spectra of several Si/SiO2 superlattices (SL) with layer thicknesses varied within 0.5–2 nm are studied using DFT-based computer modeling. Two types of structures with different interfaces between crystalline silicon and SiO2 cristobalite were studied. A relationship between the phonon states of heterosystems and the phonon modes of the initial crystals was established. Estimates of the parameters of deformation potentials are obtained, with the help of which the shifts of phonon frequencies caused by elastic strains in the materials of the SL layers are interpreted. The dependence of intense Raman lines on the SL structure has been studied. Several ways have been proposed to use this information, both for identifying the type of interface and for estimating the structural parameters. The obtained information will be useful for the spectroscopic characterization of the silicon/oxide interfaces.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Fedorova, Natalja A., Kovaleva, Alena V., Olshevskaya Ju. S., Ivanova D. A., Kozak V. V., Shubin A. A., Tarasov A. S., Varnakov S. N., Ovchinnikov S. G., Moshkina E. M., Maximova O. A., Avramov P. V., Tomilin F. N.
Заглавие : Substitution effects in spin-polarized (Cr4-xFex)0.5AC (A = Ge, Si, Al) MAX phases
Место публикации : Magnetochemistry. - 2023. - Vol. 9, Is. 6. - Ст.147. - ISSN 23127481 (eISSN), DOI 10.3390/magnetochemistry9060147
Примечания : Cited References: 59. - This study was supported by the Russian Science Foundation, project no. 21-12-00226. P.V.A. acknowledges the support of the National Research Foundation of the Republic of Korea, grant no. NRF 2021R1A2C1010455
Аннотация: The use of spintronic devices with a tunable magnetic order on small scales is highly important for novel applications. The MAX phases containing transition metals and/or magnetic ion-substituted lattices attract a lot of attention. In this study, the magnetic and electronic properties of (Cr4-xFex)0.5AC (A = Ge, Si, Al) compounds were predicted and investigated within the density functional theory. It was established that single-substituted (Cr3Fe1)0.5AC (A = Ge, Si, Al) lattices are favorable in terms of energy. An analysis of the magnetic states of the MAX phases demonstrated that their spin order changes upon substitution of iron atoms for chromium ones. It was found that mostly the (Cr4-xFex)0.5GeC and (Cr4-xFex)0.5AlC lattices acquire a ferrimagnetic state in contrast to (Cr4-xFex)0.5SiC for which the ferromagnetic spin order dominates. It was pointed out that the atomic substitution could be an efficient way to tune the magnetic properties of proposed (Cr4-xFex)0.5AC (A = Ge, Si, Al) MAX phases.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Chibisov, Andrey N., Chibisova, Mary A., Prokhorenko, Anastasiia V., Obrazcov, Kirill V., Fedorov A. S., Yu, Yang-Xin
Заглавие : Possibilities of controlling the quantum states of hole qubits in an ultrathin germanium layer using a magnetic substrate: Results from ab initio calculations
Колич.характеристики :8 с
Место публикации : Nanomaterials. - 2023. - Vol. 13, Is. 23. - Ст.3070. - ISSN 20794991 (eISSN), DOI 10.3390/nano13233070
Примечания : Cited References: 36. - This work was supported by the Russian Science Foundation of the Russian Federation (project No. 22-23-01186). The authors would like to thank them for providing access to the HPC cluster at the Center for Shared Use of Scientific Equipment and the Center for Processing and Storage of Scientific Data of the Far Eastern Branch of the Russian Academy of Sciences and the Joint Supercomputer Center of the Russian Academy of Sciences (JSCC RAS)
Аннотация: Using density functional theory in the noncollinear approximation, the behavior of quantum states of hole qubits in a Ge/Co:ZnO system was studied in this work. A detailed analysis of the electronic structure and the distribution of total charge density and hole states was carried out. It was shown that in the presence of holes, the energetically more favorable quantum state is the state |0˃, in contrast to the state |1˃ when there is no hole in the system. The favorability of hole states was found to be dependent on the polarity of the applied electric field.
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Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Slyusarenko N. V., Yushina I. D., Slyusareva E. A., Golovkina E. V., Krylova S. N., Vtyurin A. N., Krylov A. S.
Заглавие : Determination of the pore direction in a crystalline metal-organic framework by Raman spectroscopy and periodic calculations based on the electron density functional theory
Колич.характеристики :10 с
Место публикации : Optoelectron. Instrum. Data Process. - 2023. - Vol. 59, Is. 6. - P.693-702. - ISSN 87566990 (ISSN), DOI 10.3103/S8756699023060134. - ISSN 19347944 (eISSN)
Примечания : Cited References: 32. - This work was supported by the Russian Foundation for Basic Research (Russian Center of Scientific Information), project no. 21-52-12018We are grateful to Dr. Irena Senkovska for the presented DUT-8 (Ni, Co) samples
Аннотация: A method for the determination of pore orientation in metal-organic framework structures by polarized Raman spectra is proposed. The method involves sensitivity of the line intensity of Raman scattering to the geometry of propagation in a crystal. The operability of the method is shown by DUT-8 (Ni, Co) crystals. The obtained results are interpreted based on analysis of symmetry and direction of vibrations within periodic calculations of the electron density functional theory. The simultaneous approach allowed us to describe the vibrations and to find the principal crystal orientation collinear to the pore direction. The information on the pore orientation is necessary for problems of adsorption and design of complex multicomponent materials based on metal-organic framework.
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Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Zlotnikov A. O.
Заглавие : Majorana vortex modes in magnet-superconductor hybrids with a triangular lattice: local density of states study
Коллективы : International Conference on Supercondactivity and Magnetism
Место публикации : 8th International conference on supercondactivity and magnetism (ICSM2023): abstract book. - 2023. - P.177
Примечания : Cited References: 6
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Krylova S. N.
Заглавие : Calculation of the phonon spectrum of PbMnBO4 crystal using density functional theory
Колич.характеристики :9 с
Место публикации : Crystallogr. Rep. - 2023. - Vol. 68, Is. 5. - P.788-796. - ISSN 10637745 (ISSN), DOI 10.1134/S1063774523600436. - ISSN 1562689X (eISSN)
Примечания : Cited References: 31. - This study was supported by the Russian Foundation for Basic Research, project no. 21-52-12018 NNIO_а
Аннотация: The phonon dispersion and Raman spectrum of the PbMnBO4 ferromagnetic crystal have been calculated within the density functional theory. Imaginary phonon branches have been observed at the points Y, Z, and Г and along the X–S direction of the Brillouin zone, which indicates structural instability and a possible phase transition with variation in external factors (temperature and pressure). The shapes of vibrations and symmetry types of the normal modes of the crystal at the center of the Brillouin zone have been determined. The calculation results are compared with the experimental and theoretical spectra from other studies. It is shown that the vibrational mode of highest intensity at 692.5 cm–1 in the spectrum and the mode at 272.3 cm–1, corresponding to the experimental modes at 690.5 and 224.7 cm–1, are bending vibrations of oxygen atoms in distorted MnO6 octahedra.
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