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1.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Tyumentseva, Anna, V, Yaroslavtsev R. N., Stolyar S. V., Saitova, Alina T., Tyutrina, Ekaterina S., Gorbenko, Alexey S., Stolyar, Marina A., Olkhovskiy, Igor A.
Заглавие : Silica-coated iron oxide nanoparticles for DNA isolation for molecular genetic studies in hematology
Место публикации : Genet. Test. Mol. Biomark. - 2021. - Vol. 25, Is. 9. - P.611-614. - ISSN 1945-0265, DOI 10.1089/gtmb.2021.0067. - ISSN 1945-0257(eISSN)
Примечания : Cited References: 16
Предметные рубрики: OXIDATIVE STRESS
MUTATION
DAMAGE
Аннотация: Aim: To develop magnetic nanoparticles (MNPs) based on iron oxide for DNA isolation from blood cells for quantitative molecular genetic analyses of the V617F mutation in the Januskinase 2 (JAK2) gene. Materials and Methods: MNPs were synthesized by the coprecipitation method and coated with tetraethyl orthosilicate (TEOS). The size and shape of the complexes were estimated using transmission electron microscopy. Twenty blood samples from patients with myeloproliferative disorders were used for DNA isolation with the MNPs. DNA quality and compatibility for molecular genetic studies of the JAK2 V617F mutation were investigated by gel electrophoresis and real-time polymerase chain reaction (RT-PCR). Results: The average amount of DNA isolated from 150 μL of whole blood was 75.2 ng when MNPs were used and 72.5 ng when standard silica sorbent was used. There was no DNA damage observed after interaction with MNPs. RT-PCR demonstrated similar values for the JAK2 V617F mutant DNA ratios in the samples after DNA isolation with MNPs and by standard sorption on silica. Conclusions: MNPs with silicate capsules of sufficient thickness were obtained and the undesirable damaging effect of iron oxides on nucleic acids during isolation from cells were eliminated. Designed MNPs allow obtaining intact DNA for molecular genetic studies using the example of the JAK2 V617F for study.
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2.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Edelman I. S., Petrakovskaja E. A., Petrov D. A., Zharkov S. M., Khaibullin R. I., Nuzhdin V. I., Stepanov A. L.
Заглавие : FMR and TEM Studies of Co and Ni Nanoparticles Implanted in the SiO2 Matrix
Место публикации : Appl. Magn. Reson. - WIEN: SPRINGER WIEN, 2011. - Vol. 40, Is. 3. - С. 363-375. - MAY. - ISSN 0937-9347, DOI 10.1007/s00723-011-0218-4. - ISSN 1613-7507
Примечания : Cited Reference Count: 51. - Гранты: The work was supported in part by the Russian Foundation for Basic Research, grant no. 11-02-00972-a, Ministry of Education and Science of the Russian Federation, Federal Target Program "Scientific and scientific-pedagogical personnel of innovative Russia'', contract no. 02.740.11.0797, and State Program "Development of the Scientific Potential of the Higher Education School'', project no. 2.1.1/6038. S.M. Zharkov acknowledges the financial support of the Russian government contract no. 02.740.11.0568. The electron microscopy investigations were carried out at the Joint Center of the Siberian Federal University.Финансирующая организация: Russian Foundation for Basic Research [11-02-00972-a]; Ministry of Education and Science of the Russian Federation [02.740.11.0797]; State Program "Development of the Scientific Potential of the Higher Education School'' [2.1.1/6038]; Russian government [02.740.11.0568]
Предметные рубрики: FERROMAGNETIC-RESONANCE
MAGNETIC-PROPERTIES
THIN-FILMS
COBALT NANOPARTICLES
ION-IMPLANTATION
FINE PARTICLES
GRANULAR FILMS
ANISOTROPY
POLYIMIDES
RUTILE
Ключевые слова (''Своб.индексиров.''): energy dispersive x ray spectroscopy--face-centered cubic structure--fused silica plates--g factors--hexagonal close packing--high dose--high-dose implantation--implantation dose--implanted samples--line shape--magnetic parameters--matrix--metal nanoparticles--ni nanoparticles--nonsymmetric--out-of-plane--room temperature--spherical shape--subsurface layer--tem--temperature dependence--thin magnetic films--uniaxial magnetic anisotropy--cobalt--fused silica--magnetic anisotropy--nanoparticles--silica--silicon compounds--transmission electron microscopy--x ray spectroscopy--ferromagnetic resonance
Аннотация: Fused silica plates have been implanted with 40 keV Co+ or Ni+ ions to high doses in the range of (0.25-1.0) x 10(17) ions/cm(2), and magnetic properties of the implanted samples have been studied with ferromagnetic resonance (FMR) technique supplemented by transmission electron microscopy, electron diffraction and energy dispersive X-ray spectroscopy. The high-dose implantation with 3d-ions results in the formation of cobalt and nickel metal nanoparticles in the irradiated subsurface layer of the SiO2 matrix. Co and Ni nanocrystals with hexagonal close packing and face-centered cubic structures have a spherical shape and the sizes of 4-5 nm (for cobalt) and 6-14 nm (for nickel) in diameter. Room-temperature FMR signals from ensembles of Co and Ni nanoparticles implanted in the SiO2 matrix exhibit an out-of-plane uniaxial magnetic anisotropy that is typical for thin magnetic films. The dose and temperature dependences of FMR spectra have been analyzed using the Kittel formalism, and the effective magnetization and g-factor values have been obtained for Co- and Ni-implanted samples. Nonsymmetric FMR line shapes have been fitted by a sum of two symmetrical curves. The dependences of the magnetic parameters of each curve on the implantation dose and temperature are presented.
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3.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Shuvaeva M., Nuzhdin A., Bayukov O., Martyanov O., Bukhtiyarova G. A.
Заглавие : Synthesis and characterization of silica supported iron-containing catalyst for the Friedel-VCrafts benzylation of benzene
Коллективы : European conference of Control, European conference on Mechanical Engineering
Место публикации : Proceedings of the 2nd European conference of Control, and Proceedings of the 2nd European conference on Mechanical Engineering (ECC'11/ECME'11). - 2011. - С. 126-131. - ISBN 978-1-61804-057-2
Примечания : Библиогр.: 3
Аннотация: Benzylation of benzene with benzyl chloride was investigated in the temperature range 25-60°C over silica supported Fe-containing catalyst prepared by simple and reproducible method using FeSO4 as precursor. It was shown that the calcination temperature is the main parameter effecting the catalytic activity: the samples, containing 4-6wt% Fe, provide the reaction of benzene with benzyl chloride after calcinations at 400°C. Selectivity does not depend on the reaction temperature as well as iron content and is defined mainly by the ratio of the reactants. The effect of calcination temperature (300-900°C) on the catalytic properties of Fecontaining catalysts is discussed in connection with the evolution of iron species nature in the course of preparation and reaction.
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4.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Bondarenko L. S., Kovel E. S., Kydralieva K. A., Dzhardimalieva G. I., Illes E., Tombacz E., Kicheeva A. G., Kudryasheva N. S.
Заглавие : Effects of modified magnetite nanoparticles on bacterial cells and enzyme reactions
Место публикации : Nanomaterials. - 2020. - Vol. 10, Is. 8. - Ст.1499. - P.1-20. - ISSN 20794991 (ISSN), DOI 10.3390/nano10081499
Примечания : Cited References: 83. - This research was funded by the Russian Foundation for Basic Research (#19-315-50048, #19-33-90149, and #18-29-19003)
Аннотация: Current paper presents biological effects of magnetite nanoparticles (MNPs). Analyzing effects of MNP’ characteristics (zeta-potential and hydrodynamic diameters) on bacteria and their enzyme reactions was the main focus. Photobacterium phosphoreum and bacterial enzymatic reactions were chosen as bioassays. Three types of MNPs were under study: bare Fe3O4, Fe3O4 modified with 3-aminopropyltriethoxysilane (Fe3O4/APTES), and humic acids (Fe3O4/HA). Effects of the MNPs were studied at a low concentration range (< 2 mg/L) and attributed to availability and oxidative activity of Fe3+, high negative surface charge, and low hydrodynamic diameter of Fe3O4/HA, as well as higher Fe3+ content in suspensions of Fe3O4/HA. Low-concentration suspensions of bare Fe3O4 provided inhibitory effects in both bacterial and enzymatic bioassays, whereas the MNPs with modified surface (Fe3O4/APTES and Fe3O4/HA) did not affect the enzymatic activity. Under oxidative stress (i.e., in the solutions of model oxidizer, 1,4-benzoquinone), MNPs did not reveal antioxidant activity, moreover, Fe3O4/HA demonstrated additional inhibitory activity. The study contributes to the deeper understanding of a role of humic substances and silica in biogeochemical cycling of iron. Bioluminescence assays, cellular and enzymatic, can serve as convenient tools to evaluate bioavailability of Fe3+ in natural dispersions of iron-containing nanoparticles, e.g., magnetite, ferrihydrite, etc.
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5.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Babkina I. V., Volochaev M. N., Zhilova O. V., Kalinin Y. E., Kashirin M. A., Sitnikov A. V., Chehonadskih M. V., Yanchenko L. I.
Заглавие : Effect of Heat Treatment on the Stability of Nanosized (Co40Fe40B20)34(SiO2)66/ZnO/In2O3 Multilayers
Место публикации : Bull. Russ. Acad. Sci. Phys. - 2020. - Vol. 84, Is. 9. - P.1100-1103. - ISSN 10628738 (ISSN), DOI 10.3103/S1062873820090051
Примечания : Cited References: 11. - This work was supported by the RF Ministry of Science and Higher Education as part of State Task no. FZGM-2020-0007
Аннотация: An investigation is performed of the thermal stability and phase transformations of thin-film heterogeneous [(Co40Fe40B20)34(SiO2)66/ZnO/In2O3]85 multilayers obtained via ion beam sputtering. The system contains 85 layers, each consisting of a (Co40Fe40B20)34(SiO2)66 composite layer and ZnO and In2O3 semiconductor spacers. The sample structure in the initial state and after heat treatment is studied by means of X-ray diffraction. It is shown that the samples are stable at temperatures of up to 500°С. Zn2SiO4, InBO3, CoFe, and In2O3 phases form during annealing.
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6.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Belyaev B. A., Afonin A. O., Ugryumov A. V., Govorun I. V., Solovev P. N., Leksikov An. A.
Заглавие : Microstrip resonator for nonlinearity investigation of thin magnetic films and magnetic frequency doubler
Место публикации : Rev. Sci. Instrum. - 2020. - Vol. 91, Is. 11. - Ст.114705. - ISSN 00346748 (ISSN), DOI 10.1063/5.0009045
Примечания : Cited References: 40. - This work was supported by the Russian Science Foundation under Grant No. 19-72-10047
Аннотация: A structure that consists of a λ/4 stepped-impedance microstrip resonator is proposed as an instrument for the investigation of nonlinear effects in thin magnetic films and also can be used as a microwave frequency doubler. A conversion efficiency of 0.65% is observed at a one-layer 100 nm Ni80Fe20 thin film at an input signal level of 4.6 W for a 1 GHz probe signal. The maximum measured conversion efficiency (1% at 1 GHz) was achieved for the 9-layer Ni80Fe20 film where 150 nm magnetic layers were separated by SiO2 layers.
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7.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Morozov E. V., Shabanova O.V., Pavlov V.F., Falaleev O.V.
Заглавие : NMR microimaging for studying the initial stages of gelation process in colloidal silica
Коллективы : Actual problems of magnetic resonance and its application
Место публикации : Actual problems of magnetic resonance and its application: XII International youth scientific school, Kazan, 5 - 9 October 2009 : program, lecture notes, proceedings : new aspects of magnetic resonance application. - 2009. - С. 121-125
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8.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Stolyar S. V., Velikanov D. A., Tyumentseva A. V., Komogortsev S. V., Yaroslavtsev R. N., Gerasimova Yu. V., Rautskii M. V., Iskhakov R. S.
Заглавие : The manifestation of stoichiometry deviation in silica-coated magnetite nanoparticles
Коллективы : Российская академия наук, Физико-технический институт им. Е.К. Завойского ФИЦ Казанского научного центра РАН, Казанский (Приволжский) федеральный университет, Euro-Asian Symposium "Trends in MAGnetism", "Trends in MAGnetism", Euro-Asian Symposium
Место публикации : VIII Euro-Asian symposium "Trends in magnetism" (EASTMAG-2022): Book of abstracts/ program com. S. G. Ovchinnikov [et al.]. - 2022. - Vol. 2, Sect. M: Magnetism in biology and medicine. - Ст.M.P15. - P.451-453. - ISBN 978-5-94469-051-7
Примечания : Cited References: 4. - The study was supported by the Russian Science Foundation and the Krasnoyarsk Region Science and Technology Support Fund., grant No. 22-14-20020
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9.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Pryazhnikov M. I., Zhigarev V. A., Minakov A. V., Nemtsev I. V.
Заглавие : Spontaneous imbibition experiments for enhanced oil recovery with silica nanosols
Колич.характеристики :14 с
Место публикации : Capillarity. - 2024. - Vol. 10, Is. 3. - P.73-86. - ISSN 27092119 (ISSN), DOI 10.46690/capi.2024.03.02. - ISSN 26523310 (eISSN)
Примечания : Cited References: 53. - This work is partially financed by Ministry of Science and Higher Education of the Russian Federation (No. FSRZ2020-0012)
Аннотация: Experimental oil displacement as a result of spontaneous imbibition of silica nanosols has been carried out using two types of sandstone as the reservoir rock. The permeability of the cores ranged from 0.34 to 333 mD, while the porosity was 11% and 22%, respectively. During the research, the influence of the concentration and nanoparticle size, as well as the permeability of the rock, on the process of spontaneous imbibition, was studied. Silica nanosols were considered as an object of study. The nanoparticle size ranged from 10 to 35 nm. The mass concentration of nanoparticles varied from 0.01% to 0.25%. It was found that the use of silica nanosols significantly increases the rate of the spontaneous imbibition process. It was established that a silica nanosol with a nanoparticle size of 10 nm and a concentration of 0.25% allows to displace more than six times oil compared to the reservoir water model in the same time. As a result, it was shown that the oil displacement efficiency and the efficiency of spontaneous imbibition increase along with an increase in the nanoparticle concentration and a decrease in the nanoparticle size.
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10.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Buktiyarova G.A., Shuvaeva М.А., Bayukov O. A., Yakushkin S.S., Martyanov O.N.
Заглавие : Facile synthesis of nanosized е-РегОз particles on the silica support
Место публикации : J. Nanopart. Res. - 2011. - Vol. 13, Is. 10. - Ст.5527-5534. - DOI 10.1007/sl 1051-011-0542-5
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11.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Stolyar S. V., Yaroslavtsev R. N., Tyumentseva A. V., Komogortsev S. V., Tyutrina E. S., Saitova A. T., Gerasimova Yu. V., Velikanov D. A., Rautskii M. V., Iskhakov R. S.
Заглавие : Manifestation of stoichiometry deviation in silica-coated magnetite nanoparticles
Место публикации : J. Phys. Chem. C. - 2022. - Vol. 126, Is. 17. - P.7510-7516. - ISSN 19327447 (ISSN), DOI 10.1021/acs.jpcc.2c00349
Примечания : Cited References: 30. - This work was supported by the Russian Science Foundation and the Krasnoyarsk Region Science and Technology Support Fund, grant No. 22-14-20020. We are grateful to the Center of collective use of FRC KSC SB RAS for the provided equipment
Аннотация: Iron oxide nanoparticles were synthesized by the coprecipitation method. Two varying Fe3O4/tetraethoxysilane ratios were used for silanization: 1:1.3 and 1:4.5. The samples were investigated using transmission electron microscopy, ferromagnetic resonance, IR spectroscopy, and magnetometry. Magnetic measurements have shown that the magnetite core in nanoparticles has a higher magnetization than stoichiometric magnetite nanoparticles of the same size. The increased magnetization was caused by the deviation of the magnetite stoichiometry due to the interaction with the silicate coating. The blocking temperature distribution was determined from the temperature dependence of the coercive force and from the ZFC/FC dependencies. Nanoparticles with a thicker shell have shown greater efficiency in DNA isolation.
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12.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Калинин Д. В., Сердобинцева В. В., Шабанов, Василий Филиппович
Заглавие : Новый метод получения ФК-опаловых пленок путем укладки монодисперсных сферических частиц кремнезема в регулярную структуру в среде поверхностно-активного вещества
Место публикации : Российские нанотехнологии. - 2009. - Т. 4, № 5-6. - С. 94-97. - ISSN 1992-7223. - ISSN 1993-4068(eissn)
УДК : 681.7.066+621.3.049.76+778.38
Аннотация: Разработан принципиально новый метод укладки монодисперсных сферических частиц кремнезема (МСЧК) в монокристаллические опаловые пленки на твердой плоской подложке из лиофильных суспензий МСЧК в диметилсульфоксиде. Метод позволяет получать опаловые пленки высокого оптического качества, не содержащие доменов, двойников и имеющие минимум микротрещин, более качественные, чем в методе подвижного мениска, и перспективен для получения пленок на металлических и пластиковых подложках, а также прямого получения гетероструктур.Fundamentally new technology of MSSP stacking in monocrystalline opal films at solid flat base of lyophilic MSSP suspensions in dimethyl sulfoxide is elaborated. This method makes possible high-quality, domains and twins-free opal films with a minimum of micro cracks than the method of mobile meniscus. It is promising to produce heterostructures and films on metal and plastic base.
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13.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Knyazev Yu. V., Yakushkin S. S., Balaev D. A., Dubrovskiy A. A., Semenov S. V., Bayukov O. A., Kirillov V. L., Martyanov O. N.
Заглавие : Magnetic Properties of Ultrafine ε-Fe2O3 Nanoparticles in a Silicon Xerogel Matrix
Место публикации : Bull. Russ. Acad. Sci. Phys. - 2019. - Vol. 83, Is. 7. - P.875-877. - ISSN 10628738 (ISSN), DOI 10.3103/S1062873819070219
Примечания : Cited References: 11
Аннотация: A new metamaterial is obtained on the basis of ε-Fe2O3 nanoparticles immobilized in a xerogel matrix. Samples are synthesized by impregnating SiO2 hydrogel with iron (II) salts with subsequent drying and calcination. The structure and magnetic properties of the composites are probed using transmission electron microscopy, X-ray diffraction, Mössbauer spectroscopy, and static magnetic measurements. © 2019, Allerton Press, Inc.
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14.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Yakushkin S. S., Dubrovskiy A. A., Balaev A. D., Shaykhutdinov K. A., Bukhtiyarova G. A., Martyanov O. N.
Заглавие : Magnetic properties of few nanometers ɛ-Fe2O3 nanoparticles supported on the silica
Место публикации : J. Appl. Phys.: American Institute of Physics, 2012. - Vol. 111, Is. 4. - Ст.44312. - ISSN 0021-8979, DOI 10.1063/1.3686647
Примечания : Cited References: 27. - authors thank A. D. Balaev and N. V. Volkov for fruitful discussions and comments. This work was supported by Program of RAS No. 27.46.
Предметные рубрики: HIGH-TEMPERATURE
IRON
STABILIZATION
OXIDE
GEL
Аннотация: Magnetic properties of ɛ-Fe2O3nanoparticles supported on silica with the average size of few nanometers, narrow size distribution and no admixture of any other iron oxide polymorphs are investigated. The investigation of the temperature behavior of magnetization within the temperature range from 4.2 to 1000 K revealed the presence of several magnetic subsystems in the species under study. The temperatures’ behavior of the magnetic moment value indicates ferrimagnetic ordering in the ɛ-Fe2O3nanoparticles with a Curie temperature of about 800 K and points to the existence of a significant paramagnetic contribution becoming apparent at low temperatures. According to the electron spin resonance data, the particles possess superparamagnetic behavior at temperature higher ∼120 K. The model of the magnetic structure of monophase system of few nanometers ɛ-Fe2O3nanoparticles supported on silica is proposed.
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15.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Dubrovskii A. A., Balaev D. A., Shaikhutdinov K. A., Yakushkin S. S., Bukhtiyarova G. A., Martyanov O. N.
Заглавие : The effect of the particle size on the magnetic properties of nanosized ε-Fe2O3 particles on a silica support
Коллективы : Moscow International Symposium on Magnetism, Московский государственный университет им. М.В. Ломоносова
Место публикации : Moscow Int. Symp. on Magnet. (MISM-2014): Book of abstracts. - 2014. - Ст.2OR-H-7. - P.655. - ISBN 978-5-91978-025-0
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16.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Balaev D. A., Yakushkin S. S., Dubrovskii A. A., Bukhtiyarova G. A., Shaikhutdinov K. A., Martyanov O. N.
Заглавие : Study of the high-coercivity material based on ε-Fe2O3 nanoparticles in the silica gel matrix
Место публикации : Tech. Phys. Lett.: MAIK Nauka-Interperiodica / Springer, 2016. - Vol. 42, Is. 4. - P.347-350. - ISSN 10637850 (ISSN), DOI 10.1134/S1063785016040039
Примечания : Cited References: 17. - This study was supported by the Federal Agency for Scientific Organizations of Russia (base budget financing no. V.44.1.15), the Scientific and Educational Center of Energy-Efficient Catalysis at the Novosibirsk State University, and the Russian Foundation for Basic Research (project no. 15-32-50919).
Предметные рубрики: Phase
Field
State
Oxide
Iron
Аннотация: We report the results of investigations of ε-Fe2O3 magnetic nanoparticles obtained by incipient wetness impregnation of silica gel. It was established that the obtained samples with an iron content of 12‒16% mass % containing ε-Fe2O3 nanoparticles with an average size of 10 nm on the silica gel surface exhibit a room-temperature coercivity of about 10 kOe. Along with fabrication simplicity, this fact makes the prepared samples promising for application as a magnetically hard material. © 2016, Pleiades Publishing, Ltd
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17.

Вид документа : Статья из сборника (однотомник)
Шифр издания :
Автор(ы) : Denisova E. A., Komogortsev S. V., Li O. A., Chekanova L. A., Patrusheva T. N., Eremin E. V.
Заглавие : Magnetic particles in mesoporous silica MCM-41
Коллективы : Euro-Asian Symposium "Trends in MAGnetism": Nanomagnetism
Место публикации : V Euro-Asian simposium "Trend in MAGnetism": Nanomagnetism: abstracts. - Vladivostok: FEFU, 2013. - С. 176. - ISBN 978-5-7444-3124-2
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18.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Морозов, Евгений Владимирович, Шабанова О. В., Фалалеев, Олег Владимирович
Заглавие : Применение ЯМР томографии для исследования межфазных границ в системах коллоидного кремнезема
Место публикации : Конденсир. среды и межфаз. границы. - Воронеж: Воронеж. гос. ун-т, 2012. - Т.14. № 1. - С. 60-69. - ISSN 1606-867X
Аннотация: В работе представлены результаты ЯМР томографических исследований золей коллоидного кремнезема, полученных из силикатов щелочных металлов кислотным выщелачиванием. Исследована динамика времен ядерной спин-решеточной и спин-спиновой релаксации в процессе гелеобразования, а также визуализировано пространственное распределение протекающих процессов. Рассмотрена методологическая сторона проблемы обеспечения контраста на ЯМР томограммах модельных коллоидных систем при золь-гель переходе. Экспериментально продемонстрирована актуальность разработки методологии исследования межфазных границ с помощью нового для данного направления метода.The NMR Imaging investigation results of colloid silica obtained from alkali metals silicates by acidic leaching are presented. The dynamic of nuclear spin-lattice and spin-spin relaxation times was studied during the sol-gel transfer processes and the spatial distribution of occurred processes was visualized. The methodological direction of problem associated with contrast supply on the NMR Images was examined using model colloids samples during sol-gel transfer. It was demonstrated experimentally that the development of interfaces investigation methodology seems to be very important for advance of NMR Imaging to this field of research.
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19.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Kirik S. D., Parfenov V. A., Zharkov S. M.
Заглавие : Monitoring MCM-41 synthesis by X-ray mesostructure analysis
Место публикации : Micropor. Mesopor. Mater.: Elsevier Science, 2014. - Vol. 195. - P.21-30. - ISSN 1387-1811, DOI 10.1016/j.micromeso.2014.04.012. - ISSN 1873-3093
Примечания : Cited References: 70. - The investigation was made with financial support of the Program of Presidium RAS (Project 24.37), RF State contracts No 02.740.11.0629, RFBR Grants: 11-03-00610a and 11-03-12161-ofi, RSF 14-13-000025.
Предметные рубрики: ORDERED MESOPOROUS MATERIALS
ORDERED MESOPOROUS MATERIALS
IN-SITU
POWDER DIFFRACTION
SILICA/SURFACTANT COMPOSITES
ELECTRON-MICROSCOPY
MOLECULAR-SIEVES
STABLE MCM-41
SILICA
ADSORPTION
Ключевые слова (''Своб.индексиров.''): hydrothermal stability--mcm-41--mesostructure--tem--x-ray diffraction
Аннотация: The electron density maps calculated from X-ray diffraction patterns of the mesoporous silica material MCM-41 present averaged mesostructure images which in contrast to transmission electron microscopy (TEM) images are exceptionally repeating and represent the whole sample. It was shown that the averaged mesostructure parameters such as a unit cell parameter, a pore diameter, a wall width, a pore shape estimated from the X-ray powder diffraction data in combination with the continuous electron density function approach allow monitoring continuous set of the silica framework states at different stages of the material synthesis. The mentioned technique supplemented by N 2-adsorption measurements and transmission electron microscopy was applied for consideration of the MCM-41 hydrothermal stability. Attention has been given to the variations of the synthesis conditions affecting the hydrothermal stability, in particular the maintaining the basicity of the synthesis solution as well the substitution of the synthesis solution with water or a salt solution at hydrothermal treatment. The averaged pore shape was observed to be changed from cylindrical to hexagonal-prismatic form. The observed wall thickness was in the range from 0.75 to 1.25 nm. The competition of silica polycondensation and surface hydrolysis was shown to be responsible for the variety of framework geometry and hydrothermal stability. It has been established that the pore diameter increases generally due to the osmotic pressure of water. If the pores acquire the average prismatic hexagonal shape, the sample has low hydrothermal stability. Under the conditions favorable for the polycondensation the pores have averaged cylindrical shape and material demonstrates higher hydrothermal stability. Cooperative mechanism of mesostructure destruction under hydrothermal conditions was observed using TEM data and was discussed in connection with irregular polycondensation. © 2014 Elsevier Inc. All rights reserved.
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20.

Вид документа : Статья из журнала
Шифр издания :
Автор(ы) : Deich L. I.
Заглавие : Far-infrared attenuation in glasses
Разночтения заглавия :авие SCOPUS: Far-infrared attenuation in glasses
Место публикации : Phys. Rev. B. - 1994. - Vol. 49, Is. 1. - P.109-113. - ISSN 0163-1829, DOI 10.1103/PhysRevB.49.109
Примечания : Cited References: 29
Предметные рубрики: VITREOUS SILICA
TEMPERATURE
MODEL
LOCALIZATION
ABSORPTION
SOLIDS
STATES
Аннотация: The influence of quasilocal vibrations on the far-infrared spectra of glasses is investigated under the supposition that the quasilocal vibrations are directly inactive in the attenuation. It is shown that taking into account phonon-quasilocal-vibration coupling and both medium- and short-range structure of the inhomogeneities of a photon-phonon coupling parameter can give rise to an attenuation curve similar to one observed for a-SiO2 and related materials.
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