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Study on polyester-carbon nanotube–graphite composites by small-angle neutron scattering. — Polymer nanocomposites prepared by carbon nanotube (CNT) addition were first reported in the 1990’s. Since then, a great number of scientific papers have been published on this topic. However, the great differences between the CNTs produced by different companies, the aggregation and surface characteristics of the CNT fillers, the amount of impurities and defects makes the comparison of the results difficult. The fractal dimension of fracture surfaces or of the bulk volume of prepared nanocomposites is linked to the strength, thermal and electrical conduction properties etc. of them. The studies carried out now and the description of physical characteristics of the polymer composites lead to a better understanding of the relation between the nano- and macro-characteristics, and to a more relevant comparison of the composites prepared by different laboratories and companies.
Samples with various multiwalled CNT and graphite additives were prepared in collaboration with a research group from Morocco, with the aid of a clean, economical and environmental friendly method. Small-angle neutron scattering experiments on the samples were carried out at Yellow Submarine and FSANS instruments located at the Budapest Research Reactor.
Nanostructural characteristics of the prepared ternary composites (such as the size distribution and agglomeration of the additives, and their fractal characteristics) were determined, that contributed to a better understanding of macroscopical characteristics of these composites.
Synthesis and characterization of a polyurethane carrier used for a prolonged transmembrane transfer of a chili pepper extract. — Red chili peppers have been highly valued in gastronomy and traditional medicine since ancient times. In collaboration with the University of Medicine and Pharmacy, Timisoara, a complex study on the characterization of a new carrier used for encapsulated extract has been performed.
Chili pepper extract was obtained and was physically entrapped inside polyurethane microparticles in order to diminish the irritative potential of this extract. The particle morphology was evaluated by various methods, among them small-angle neutron scattering and scanning electron microscopy (SEM) were performed by our group. SEM images indicated no difference between the capsaicin-loaded and capsaicin-free samples; in both cases the formation of 50–100 µm clusters was visible (Fig. 2), and SANS indicated no differences in the nanometer scale either.
Figure 2. SEM images of capsaicin-loaded (right) and capsaicin-free (left) samples.
The encapsulation efficacy and the drug release profile were assessed by UV-Vis spectroscopy. Bioevaluations on mice skin were performed to predict the irritative potential
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of the samples. The encapsulation of a chili pepper extract inside polyurethane microparticles lead to a non-irritative product with a prolonged release: ~30% of encapsulated extract is released within the first 8 days and a maximum 45% is reached in 2 weeks.
Mesoporous silica materials for different applications. — Various types of templated silica materials have been synthesized and studied by small-angle neutron and X-ray scattering methods. Functionalization of the pore surfaces has been achieved using simple co-condensation of two precursors, with variation of the reaction conditions, or in multistep method by subsequent treatment of the templated porous silica by organic precursors. The method of preparation and the type of additives determine the performance of the materials in different applications. Sorption studies of guest molecules and heavy metals have been performed and the performance of the materials have been optimized for achieving maximal adsorbance, and for the control of the release rate of drug molecules.
Silica based aerogels hybridized with biomolecules (proteins or polysaccharides) are also promising platforms for drug delivery applications. The composition, the pore structure and the hydrophobicity of the biopolymer aerogel predetermine the main properties, each fundamental in drug delivery applications. These properties will determine the release profile (desorption kinetics) of the drugs from the delivery system. By understanding the key factors, which connect the structure to the application, a systematic approach has been developed in designing and fine-tuning hybrid aerogel based drug delivery systems. SANS measurements monitored the deformation and the hydration of the aerogel structure upon interaction with water. In order to visualize the silica matrix and the gelatin phase, the samples were measured in various H2O/D2O concentrations in order to match the silica or the gelatin content. The measurements on half and fully saturated samples proved that the hydration of the samples did not affect the silica skeleton and the pore structure.
Structural characterization of chalcogenide systems. — Neutron- and X-ray diffraction techniques were used to study the glassy atomic structure and Reverse Monte Carlo simulations were applied to model the 3-dimensional atomic configurations and thorough mapping of the atomic parameters of the 3-component Ge-Sb-Se and 4-component As-Se-Sb-Te chalcogenides. We determined the short-range order of the amorphous Ge-Sb-Se system.
From diffraction measurements it was revealed that the short-range order is formed by the fulfillment of the 8-N rule (germanium has 4, antimony has 3 and selenium has 2 neighbors) and the presence of the chemical order (germanium and antimony bonds primarily to the selenium atom). We found that in the case of the As-Se-Sb-Te system, the 8-N rule is not fulfilled for all atoms. The As and Sb atoms have three neighbors connected to the mixed Te and Se atoms. The glassy network builds up from pyramid units, connected through 2-coordinated Se and Te atoms.
Interfacial roughness correlation in multilayers. – Interface roughness and correlation properties of magnetron sputtered Ni-Ti multilayers were investigated by off-specular x-ray and neutron scattering. GISAS (Grazing Incidence Small-Angle Scattering) measurements were performed in order to complement our reflectometry results. The aim of the experiments was to check whether the interface roughness auto- and cross-correlation can be described by the in-plane and out-of-plane correlation lengths and Hurst-exponent. In the case of X-ray GISAS on periodic samples, we had to modify the linear approximation in the frames of the Distorted-Wave Born Approximation for large scattering angles and roughness.
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Taking into account the non-linear terms, we showed the limitations of the linear approximation, which can lead to erroneous interpretation of experimental results in respect to the value of the in-plane correlation length and the wavelength dependence of roughness replication. Neutron GISAS experiments (Garching, FRM II) revealed non-isotropic roughness in neutron supermirrors and presence of two different length scale roughness components.
Consequently, we have to modify the roughness models generally used for mirror analyses.
Investigation of willemite with different ions added. — The main parameters of willemite:
Zn2SiO4, trigonal, R3, with hexagonal axes: a =13.948(2) Å, c = 9.315(2) Å, Z= 18, Dx = 4.224 g.cm-3. The structure of willemite has been refined by Rietveld method and an R value of 0.032 was achieved for powder samples.
The addition of different ions creates color centers in willemite, making it a good luminophore powder. The treatment of addition of ions can be processed by a high-temperature thermal dry way or a newly discovered low-temperature wet treatment. One of the goals was to check the result of the new treatment and to obtain accurate atomic parameters in order to provide a structural basis for the evaluation of the optical properties of willemite.
By the combined use of neutron and X-ray diffraction, we could determine that the different metallic ions are built in in a different way. Some of them created a separate phase (Ce, Eu), some of them could be built into the original willemite structure (Mn, Tb).
Characterisation of forming techniques and firing temperatures of archaeological ceramic artefacts. — Neutron tomography experiments on archaeological and experimental reference samples have been performed at the RAD instrument of the Budapest Neutron Centre. The aim of the project was to investigate the suitability of non-destructive neutron computer tomography as a means for identifying the forming techniques used in the production of ancient organic-tempered pottery. Specifically, it was aimed at creating a three-dimensional (3D) model of the distribution of the voids/carbonised particles left within the ceramic matrix resulting from the complete or partial combustion of organic fibres within samples of ancient pottery and modern replicas. Through statistical analysis of the orientation of these fibrous voids/particles in 3D space, the preferential alignments were detected, which in turn correlated with suspected or known forming techniques. This information can be used to further refine the detection of preferential particle alignments by more conventional and cheaper methods, in particular by petrographic analysis of ceramic thin sections.
A new, systematic and larger set of investigated samples (36 samples from 3 geological sources, 12 different firing temperatures between 500°C and 1000°C) and archaeological samples (12 samples from Keszthely, Hungary) have been measured at the Yellow Submarine and F-SANS instruments of the Budapest Neutron Centre in order to determine the correlation between the maximum firing temperature of the ceramic materials and the Porod exponent gained from the SANS measurements. Previous experiments on a smaller set of samples have already shown linear dependence between the maximum firing temperature and the SANS curves. Therefore, the main objectives of the new experiments were to examine 1) whether the aforementioned linear dependence only applies to a certain range of firing temperatures and 2) how clays from different geological sources correlate to each other. Our results show that the linear dependence can be observed between 550°C and 950°C, which might be explained by the mineral phase transitions and vitrification occurring in this range of temperatures. Clays from different geological origins, while displaying linear temperature
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dependency, show different levels of the power exponent – firing temperature master curves.
These findings reveal the possibility to identify the characteristic processing temperatures at different provenances of the clay artifacts, after performing an extensive calibration of the SANS data using local reference samples.
Time-of-flight neutron diffraction (TOF-ND) analysis of Late Bronze Age metallic artifacts. — As a member of "Momentum Mobility research team" (From bones, bronzes and sites to society: Multidisciplinary analysis of human mobility and social changes in Bronze Age Hungary (2500–1500 BC), http://mobilitas.ri.btk.mta.hu), György Káli has investigated several sets of finds, especially bronze weapons and jewelry items from the Carpathian Basin. The tests covered the phase compositions, chemical distributions, preferred orientations and dislocation densities of the alloys to unfold the manufacturing techniques. These pieces of information are of great help for the archeology and historical sciences to determine the social, cultural and trade links between distant regions of a given period.
Other archaeometric investigations. — As participants of the IPERION CH (Integrated Platform for the European Research Infrastructure On Cultural Heritage) project, we have performed a large set of neutron diffraction studies in various fields (ancient metal, ceramic and other objects).
Study of oriental and European carbon steel swords (Iperion). — Earlier, we have shown that the oriented distribution of cementite inclusions is a very efficient resource for the sorting of steels produced by different forging techniques. Besides that, texture and stress analyses have been performed on the ferrite phase as well on a large set of samples from several European collections. These non-destructively gained results on the sample bulk are very helpful to the archaeo-metallurgists to unfold the medieval steel production techniques.
The 'Budapest Horse': A comprehensive technical investigation has been performed on the world-famous statuette called Budapest Horse and Rider attributed to Leonardo da Vinci. This small bronze of the Budapest Museum of Fine Arts was taken first in 2017 to the BNC to carry out non-destructive experiments to collect new information on the inside of both parts. Now PGAA and widespread neutron diffraction analyses have been performed. For that, two new detector banks have been installed to the TOF beam. A normal (90°) and a reversed one on the opposite side for diffraction tomography. Our results – of major international interest in the light of the investigations performed in the Washington National Gallery of Art in 2009 – will be published soon.
Grants
H2020-INFRADEV-1-2015-1: 676548 - BrightnESS - Building a research infrastructure and synergies for highest scientific impact on ESS (L. Rosta, 2015-2018)
H2020-IPERION CH-2014-2015: 654028 (L. Rosta, 2015-2019)
H2020-654000, SINE2020 Science & Innovation with Neutrons in Europe in 2020 Training (L.
Rosta, 2015-2019)
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International cooperation
HAS Romania Academic exchange, Institute of Chemistry Timisoara
HAS Romania Academic exchange, Institute of Physical Chemistry Bucharest TéT Bilateral Project, Université Pierre et Marie Curie, Paris
Publications
Articles
1. Alekberov RI, Isayev AI, Mekhtiyeva SI, Fábián M: Local structures and optical properties of As-Se-Te(S) chalcogenide glasses. PHYSICA B 550: 367-375 (2018) 2. Borcan L-C, Dudás Z, Len A, Füzi J, Borcan F, Tomescu MC: Synthesis and
characterization of a polyurethane carrier used for a prolonged transmembrane transfer of a chili pepper extract. INT J NANOMED 13: 7155-7166 (2018)
3. Dudás Z, Fagadar-Cosma E, Len A, Románszki L, Almásy L, Vlad-Oros B, Dascălu D, Krajnc A, Kriechbaum M, Kuncser A: Improved optical and morphological properties of vinyl-substituted hybrid silica materials incorporating a Zn-metalloporphyrin.
MATERIALS 11:4 565/1-21 (2018)
4. Dulgheru N, Gartner M, Anastasescu M, Stoica M, Nicolescu M, Stroescu H, Atkinson I, Bratan V, Stanculescu I, Szekeres A, Terziyska P, Fábián M: Influence of compositional variation on the optical and morphological properties of GeSbSe films for optoelectronics application. INFRARED PHYS TECHN 93: 260-270 (2018)
5. Kasztovszky Z, Lázár K, Kovács Kis V, Len A, Füzi J, Markó A, Biró KT: A novel approach in the mineralogy of Carpathian mahogany obsidian using complementary methods.
QUATERN INT 467: 332-341 (2018)
6. Kulvelis YV, Shvidchenko AV, Aleksenskii AE, Yudina EB, Lebedev VT, Shestakov MS, Dideikin AT, Khozyaeva LO, Kuklin AI, Török G, Rulev MI, Vul A-Ya: Stabilization of detonation nanodiamonds hydrosol in physiological media with poly(vinylpyrrolidone). DIAM RELAT MATER 87: 78-89 (2018)
7. Lebedev VT, Dubovsky IM, Török G, Serebrov AP: Spin echo spectrometry using very cold neutrons. J SURF INVESTIG-X-RAY 12:3 426-430 (2018)
8. Lehofer B, Golub M, Kornmueller K, Kriechbaum M, Martinez N, Nagy G, Kohlbrecher J, Amenitsch H, Peters J, Prassl R: High hydrostatic pressure induces a lipid phase transition and molecular rearrangements in low-density lipoprotein nanoparticles.
PART PART SYST CHAR 35:9 1800149/1-13 (2018)
9. Leng YC, Li QT, Tian Q, Chen XY, Almásy L, Liu YL, Sun GG, Tuo XG, Yan MH, Henderson MJ: (Ce-Al)-oxide pillared bentonite: a high affinity sorbent for plutonium. J HAZARD MATER 352: 121-129 (2018)
10. Li HL, Wang KH, Tuo XG, Almásy L, Tian Q, Sun GG, Henderson MJ, Li QT, Wacha A, Courtois J, Yan M: Thickness determination of ultrathin Poly(acrylic acid) shell on γ-Fe2O3 nanocore via small-angle scattering. MATER CHEM PHYS 204: 236-242 (2018) 11. Markhulia J, Kekutia Sh, Mitskevich N, Mikelashvili V, Saneblidze L, Leladze N, Jabua
Z, Sacarescu L, Kriechbaum M, Almásy L: Synthesis and in vivo investigation of therapeutic effect of magnetite nanofluids in mouse prostate cancer model. DIG J NANOMATER BIOS 13:4 1081-1090 (2018)
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12. Nagy G, Sproll V, Gasser U, Schmidt TJ, Gubler L, Balog S: Scaling the graft length and graft density of irradiation-grafted copolymers. MACROMOL CHEM PHYS 219:21 1800311/1-7 (2018)
13. Pashirova TN, Zueva IV, Petrov KA, Lukashenko SS, Nizameev IR, Kulik NV, Voloshina AD, Almásy L, Kadirov MK, Masson P, Souto EB, Zakharova LY, Sinyashin OG: Mixed cationic liposomes for brain delivery of drugs by the intranasal route: The acetylcholinesterase reactivator 2-PAM as encapsulated drug model. COLLOID SURFACE B 171: 358-367 (2018)
14. Petrenko VI, Artykulnyi OP, Bulavin LA, Almásy L, Garamus VM, Ivankov OI, Grigoryeva NA, Vekas L, Kopcansky P, Avdeev MV: On the impact of surfactant type on the structure of aqueous ferrofluids. COLLOID SURFACE A 541: 222-226 (2018)
15. Simonenko EP, Simonenko NP, Kopitsa GP, Almásy L, Gorobtsov FYu, Sevastyanov VG, Kuznetsov NT: Heat-treatment-induced evolution of the mesostructure of finely divided Y3Al5O12 produced by the sol–gel method. RUSS J INORG CHEM+ 63:6 691-699 (2018)
16. Tian Q, Yan G, Bai L, Li X, Zou L, Rosta L, Wacha A, Li Q, Krakovský I, Yan M, Almásy L:
Phase mixing and separation in polyester polyurethane studied by small-angle scattering: A polydisperse hard sphere model analysis. POLYMER 147: 1-7 (2018) 17. Tian Q, Yan G, Bai L, Chen J, Liu D, Chen L, Sun L, Huang C, Chen B, Nagy G, Wacha A,
Almási L: Calibration of the Suanni small-angle neutron scattering instrument at the China Mianyang Research Reactor. J APPL CRYSTALLOGR 51:6 1662-1670 (2018) 18. Yorov KE, Shekunova TО, Baranchikov АЕ, Kopitsa GP, Almásy L, Skogareva LS, Kozik
VV, Malkova АN, Lermontov SА, Ivanov VK: First rare-earth phosphate aerogel: sol–
gel synthesis of monolithic ceric hydrogen phosphate aerogel. J SOL-GEL SCI TECHN 85: 574-584 (2018)
19. Zhu S, Leng Y, Yan M, Tuo X, Yang J, Almásy L, Tian Q, Sun G, Zou L, Li Q, Courtois J, Zhang H: Bare and polymer coated iron oxide superparamagnetic nanoparticles for effective removal of U (VI) from acidic and neutral aqueous medium. APPL SURF SCI 447: 381-387 (2018)
20. Artykulnyi OP, Petrenko VI, Bulavin LA, Almásy L, Grigoryeva NA, Avdeev MV, Aksenov VL: Влияние полиэтиленгликоля на структуру мицеллярных растворов олеата натрия в воде по данным малоуглового рассеяния нейтронов (Impact of polyethylene glycole on structure of sodium oleate micellar solution in water according to small angle neutron scattering, in Russian). POVERKHNOST FIZ KHIM MEKH 2018:12 3-10 (2018)
Conference proceeding
21. Petrenko VI, Nagornyi AV, Gapon IV, Vekas L, Garamus VM, Almásy L, Feoktystov AV, Avdeev MV: Magnetic fluids: structural aspects by scattering techniques. In: Modern Problems of Molecular Physics, Selected Reviews from the 7th International Conference
“Physics of Liquid Matter: Modern Problems”, Kyiv, Ukraine, May 27 ̶ 31, 2016, Eds.:
Bulavin LA, Chalyi AV, SPRINGER PROC PHYS 197 pp. 205-226 (2018) See also: R-J.6, R-K.2
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