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Lipatova T, Malinova L, Eremin A. Behavioral economics strategies for promoting adherence to treatment in heart failure patients. Eur Heart J 2021. [DOI: 10.1093/eurheartj/ehab724.3121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
Heart failure (HF) is characterized by an increased risk of both fatal and nonfatal adverse cardiovascular events, which required life-long and costly treatment. At the same time every cardiology practitioner is well aware, that despite huge efforts on patient's education there remains a substantial part of patients who do not always make rational choices regarding their treatment. Patient's knowledge does not always translate into adherence, so we must find ways to minimize the intent-behavior gap to improve the efficacy of HF treatment. We presume that behavioral economics can provide us with tools that will promote positive present behavior of patients.
The purpose of the study was to examine the utility of behavioral economics-related concepts in understanding long-term treatment strategy in heart failure patients and acute heart failure survivors.
Methods
We performed an open prospective study involving male patients with both chronic and acute heart failure (CHF n=65 and AHF n=54). Involved patients were surveyed on symptom severity, behavioral economics “parameters”. Cognitive complexity was measured via “real life” case simulations. We assessed stress and depression with HADS and Zung's scales serially: on admission, 3d day of hospitalization and day before discharge. In patients with AHF, first assessment was performed after clinical stabilization. The primary outcomes were set as an adherence to prescribed medication assessed 6 and 36 months after discharge, rehospitalization due to cardiovascular reasons and self-assessed well-being.
Results
We observed opposite patterns of stress dynamics in CHF and AHF groups. AHF patients demonstrated significant reduction of stress level on the 3d day since admission: 9.0 (7.1; 9.9) vs 6.4 (5.7; 7.4) units, p=0.037, with further increase at discharge, while in CHF patients there was tendency to significant change in parameter was absent.
Patients who survived AHF demonstrated higher 6 month adherence to prescribed medication (62.9% vs 49.2%, p=0.047), at the same time there was the strong positive correlation between medication's price and self-induced therapy interruption (R=0.74, p<0.05). Both AHF and CHF reported financial planning as the major contributor for decision making in “real life” cases. Surprisingly in study population self-assessed well-being did not correlated with rehospitalization rate.
Parameters that were significantly associated with CV rehospitalization included symptoms at admission (OR 2.1 CI 1.4; 3.2, p=0.002), regularly saving money (OR =2.7 CI 1.9; 4.6, p=0.001) and stress level at discharge (OR 1.6 CI 1.1; 2.4, p=0.027).
Conclusion
Received results may be useful to identify heart failure patients at higher risk of self-induced treatment interruption. These patients could be offered focused support and counseling designed to enhance adherence to prescribed medication in order to improve long-term heart failure outcomes.
Funding Acknowledgement
Type of funding sources: None.
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Affiliation(s)
- T Lipatova
- Saratov State Medical University, Saratov, Russian Federation
| | - L Malinova
- Saratov State Medical University, Saratov, Russian Federation
| | - A Eremin
- Saratov State Medical University, Saratov, Russian Federation
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2
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Lunchenkov N, Polushkin V, Ignatov E, Eremin A. 4.10-P21Immigrant men who have sex with men in Moscow, Russia. Common issues and implications for prevention of HIV among key-population groups. Eur J Public Health 2018. [DOI: 10.1093/eurpub/cky048.160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
| | - V Polushkin
- Sechenov First Moscow State Medical University, Russian Federation
| | - E Ignatov
- AIDS CENTER foundation, Russian Federation
- Plekhanov Russian University for Economics, Russian Federation
| | - A Eremin
- AIDS CENTER foundation, Russian Federation
- RUDN University, Russian Federation
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3
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Salili SM, Ostapenko T, Kress O, Bailey C, Weissflog W, Harth K, Eremin A, Stannarius R, Jákli A. Rupture and recoil of bent-core liquid crystal filaments. Soft Matter 2016; 12:4725-4730. [PMID: 27140824 DOI: 10.1039/c6sm00290k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The recoil process of free-standing liquid crystal filaments is investigated experimentally and theoretically. We focus on two aspects, the contraction speed of the filament and a spontaneously formed undulation instability. At the moment of rupture, the filaments buckle similarly to the classical Euler buckling of elastic rods. The tip velocity decays with decreasing filament length. The wavelength of buckling affinely decreases with the retracting filament tip. The energy gain related to the decrease of the total length and surface area of the filaments is mainly dissipated by layer rearrangements during thickening of the fibre. A flow back into the meniscus is relevant only in the final stage of the recoil process. We introduce a model for the quantitative description of the filament retraction speed. The dynamics of this recoil behaviour may find relevance as a model for biology-related filaments.
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Affiliation(s)
- S M Salili
- Chemical Physics Interdisciplinary Program and Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA.
| | - T Ostapenko
- Institute of Experimental Physics, Otto von Guericke University, Universitätsplatz 2, 39106 Magdeburg, Germany.
| | - O Kress
- Chemical Physics Interdisciplinary Program and Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA.
| | - C Bailey
- Leidos, 3745 Pentagon Blvd., Beavercreek, OH 45431, USA
| | - W Weissflog
- Martin Luther University Halle-Wittenberg, Department of Chemistry, Physical Chemistry, von-Danckelmann-Platz 4, 06120 Halle, Germany
| | - K Harth
- Institute of Experimental Physics, Otto von Guericke University, Universitätsplatz 2, 39106 Magdeburg, Germany.
| | - A Eremin
- Institute of Experimental Physics, Otto von Guericke University, Universitätsplatz 2, 39106 Magdeburg, Germany.
| | - R Stannarius
- Institute of Experimental Physics, Otto von Guericke University, Universitätsplatz 2, 39106 Magdeburg, Germany.
| | - A Jákli
- Chemical Physics Interdisciplinary Program and Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA.
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4
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Kredentser S, Eremin A, Davidson P, Reshetnyak V, Stannarius R, Reznikov Y. Light-induced Soret effect and adsorption of nanocrystals in organic solvents. Eur Phys J E Soft Matter 2016; 39:38. [PMID: 27021655 DOI: 10.1140/epje/i2016-16038-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 01/21/2016] [Indexed: 06/05/2023]
Abstract
A light-induced Soret effect accompanied by photoinduced adsorption of pigment nanoparticles is described in organic solvents. We report an unexpected inversion of the nanoparticle flux which is directed along the temperarture gradient at short exposures to the light and switches against the gradient at longer exposures. This change of flux direction is due to light-induced adsorption of the nanocrystals onto the substrates of the cell.
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Affiliation(s)
- S Kredentser
- Institute of Physics of National Academy of Sciences of Ukraine, Pr. Nauky 46, 03028, Kyiv, Ukraine.
| | - A Eremin
- Otto-von-Guericke-Universität Magdeburg, 4120, Magdeburg, Germany
| | - P Davidson
- Laboratoire de Physique des Solides, UMR CNRS 8502, Université Paris-Sud, 91405, Orsay, France
| | - V Reshetnyak
- Taras Shevchenko National University of Kyiv, 01601, Kyiv, Ukraine
| | - R Stannarius
- Otto-von-Guericke-Universität Magdeburg, 4120, Magdeburg, Germany
| | - Yu Reznikov
- Institute of Physics of National Academy of Sciences of Ukraine, Pr. Nauky 46, 03028, Kyiv, Ukraine
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5
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Eremin A, Geng Y, Stannarius R, Ostapenko T, Challa PK, Gleeson JT, Jákli A, Klein S. Correction: Peculiarities of the magneto-optical response in dispersions of anisometric pigment nano-particles. RSC Adv 2016. [DOI: 10.1039/c6ra90089e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Correction for ‘Peculiarities of the magneto-optical response in dispersions of anisometric pigment nano-particles’ by A. Eremin et al., RSC Adv., 2016, 6, 80666–80669.
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Affiliation(s)
- A. Eremin
- Otto-von-Guericke-Universität Magdeburg
- FNW/IEP/ANP
- 39016 Magdeburg
- Germany
| | - Y. Geng
- Otto-von-Guericke-Universität Magdeburg
- FNW/IEP/ANP
- 39016 Magdeburg
- Germany
| | - R. Stannarius
- Otto-von-Guericke-Universität Magdeburg
- FNW/IEP/ANP
- 39016 Magdeburg
- Germany
| | - T. Ostapenko
- Max Planck Institute for Dynamics and Self-Organization (MPIDS)
- 37077 Göttingen
- Germany
| | - P. K. Challa
- Department of Physics
- Kent State University
- Kent
- USA
| | | | - A. Jákli
- Liquid Crystal Institute
- Kent State University
- Kent
- USA
| | - S. Klein
- HP Laboratories
- Bristol BS34 8QZ
- UK
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6
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Sebastián N, Tamba MG, Stannarius R, de la Fuente MR, Salamonczyk M, Cukrov G, Gleeson J, Sprunt S, Jákli A, Welch C, Ahmed Z, Mehl GH, Eremin A. Mesophase structure and behaviour in bulk and restricted geometry of a dimeric compound exhibiting a nematic–nematic transition. Phys Chem Chem Phys 2016; 18:19299-308. [DOI: 10.1039/c6cp03899a] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We demonstrate a liquid crystal system exhibiting a variety of modulated structures on different length-scales: from helicoidal nematic to modulated smectic.
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7
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Eremin A, Geng Y, Stannarius R, Ostapenko T, Challa PK, Gleeson JT, Jákli A, Klein S. Peculiarities of the magneto-optical response in dispersions of anisometric pigment nano-particles. RSC Adv 2016. [DOI: 10.1039/c6ra12020b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We demonstrate an unusually strong magneto-optical response of elongated plate-shaped pigment particles in magnetic fields ranging from 0 to 25 T.
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Affiliation(s)
- A. Eremin
- Otto-von-Guericke-Universität Magdeburg
- FNW/IEP/ANP
- 39016 Magdeburg
- Germany
| | - Y. Geng
- Otto-von-Guericke-Universität Magdeburg
- FNW/IEP/ANP
- 39016 Magdeburg
- Germany
| | - R. Stannarius
- Otto-von-Guericke-Universität Magdeburg
- FNW/IEP/ANP
- 39016 Magdeburg
- Germany
| | - T. Ostapenko
- Max Planck Institute for Dynamics and Self-Organization (MPIDS)
- 37077 Göttingen
- Germany
| | - P. K. Challa
- Department of Physics
- Kent State University
- Kent
- USA
| | | | - A. Jákli
- Liquid Crystal Institute
- Kent State University
- Kent
- USA
| | - S. Klein
- HP Laboratories
- Bristol BS34 8QZ
- UK
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8
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Abstract
We demonstrate the nanostructure and filament formation of a novel liquid crystal phase of a dimeric mesogen below the twist–bend nematic phase.
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Affiliation(s)
- M. G. Tamba
- Department of Nonlinear Phenomena
- Institute for Experimental Physics
- Otto von Guericke University Magdeburg
- Magdeburg
- Germany
| | - S. M. Salili
- Liquid Crystal Institute
- Kent State University
- Kent
- USA
| | - C. Zhang
- Liquid Crystal Institute
- Kent State University
- Kent
- USA
| | - A. Jákli
- Liquid Crystal Institute
- Kent State University
- Kent
- USA
| | - G. H. Mehl
- Department of Chemistry
- University of Hull
- Hull HU6 7RX
- UK
| | - R. Stannarius
- Department of Nonlinear Phenomena
- Institute for Experimental Physics
- Otto von Guericke University Magdeburg
- Magdeburg
- Germany
| | - A. Eremin
- Department of Nonlinear Phenomena
- Institute for Experimental Physics
- Otto von Guericke University Magdeburg
- Magdeburg
- Germany
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9
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Aghsaee M, Drakon A, Eremin A, Dürrstein SH, Böhm H, Somnitz H, Fikri M, Schulz C. Experimental investigation and modeling of the kinetics of CCl4 pyrolysis behind reflected shock waves using high-repetition-rate time-of-flight mass spectrometry. Phys Chem Chem Phys 2013; 15:2821-8. [PMID: 23338791 DOI: 10.1039/c2cp42574b] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The pyrolysis kinetics of CCl(4) behind reflected shock waves was studied with high-repetition-rate time-of-flight mass spectrometry. For modeling, quantum mechanical calculations were performed to evaluate the dissociation energies of CCl bonds for the different CCl(x) (x = 1 to 4) radicals. Good agreement with the JANAF thermochemical table was found. With the reaction mechanism developed for CCl(4) decomposition satisfactory agreement with experimental results was obtained. The investigations show the importance of C(2)Cl(2) formation for understanding the processes of carbon cluster growth leading to carbonaceous particle formation.
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Affiliation(s)
- M Aghsaee
- IVG, Institute for Combustion of Gasdynamics, University of Duisburg-Essen, Duisburg, Germany
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10
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Morys M, Trittel T, Eremin A, Murphy P, Stannarius R. Tension of freely suspended fluid filaments. Phys Rev E Stat Nonlin Soft Matter Phys 2012; 86:040501. [PMID: 23214519 DOI: 10.1103/physreve.86.040501] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Indexed: 06/01/2023]
Abstract
Stable fluid filaments with diameters of several micrometers and slenderness ratios well above 1000 are unique objects formed by some liquid crystalline phases of bent-core mesogens. We present a technique to determine filament tensions from their deflection under defined loads. A strong temperature dependence is observed, with a minimum near the clearing temperature. Both the nonlinear relation between filament tension and diameter and the substantial increase of the tension with lower temperatures indicate contributions of volume terms, in addition to surface capillary forces. We discuss a model that relates these bulk terms to elastic forces, originating from the undulated smectic layer structure. This model can explain the origin of the filament stability.
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Affiliation(s)
- M Morys
- Otto von Guericke University Magdeburg, Institute of Experimental Physics, Universitätsplatz 2, D-39106 Magdeburg, Germany
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11
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Eremin A, Baumgarten S, Harth K, Stannarius R, Nguyen ZH, Goldfain A, Park CS, Maclennan JE, Glaser MA, Clark NA. Two-dimensional microrheology of freely suspended liquid crystal films. Phys Rev Lett 2011; 107:268301. [PMID: 22243186 DOI: 10.1103/physrevlett.107.268301] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Revised: 08/21/2011] [Indexed: 05/31/2023]
Abstract
Smectic liquid crystals form freely-suspended, fluid films of highly uniform structure and thickness, making them ideal systems for studies of hydrodynamics in two dimensions. We have measured particle mobility and shear viscosity by direct observation of the gravitational drift of silica spheres and smectic islands included in these fluid membranes. In thick films, we observe a hydrodynamic regime dominated by lateral confinement effects, with the mobility of the inclusion determined predominantly by coupling of the fluid flow to the fixed boundaries of the film. In thin films, the mobility of inclusions is governed primarily by coupling of the fluid to the surrounding air, as predicted by Saffman-Delbrück theory.
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Affiliation(s)
- A Eremin
- Otto-von-Guericke Universität Magdeburg, Institute for Experimental Physics, D-39016 Magdeburg, Germany
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12
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Abstract
Abstract
The formation of condensed particles in atmospheric ethylene-oxygen and acetylene-air premixed flames catalyzed by the vapours of Fe(CO)5 and Mo(CO)6 was studied in the wide range of C/O ratio. Laser scattering and extinction measurements were carried out in a wide frame of flame conditions. The structure and the morphology of formed particles were analyzed using electron microscope. Different formation of the particles takes place due to the fuels and also to the catalyst. In the C2H2/air flame catalyzed with Mo(CO)6, particle formation starts at about threshold of soot formation (C/O ~ 0.6), while in the flames doped with Fe(CO)5, particle formation starts already in the lean range of both premixed flames investigated here.
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Affiliation(s)
| | | | | | - H.Gg. Wagner
- University Goettingen, Institute for Physical Chemistry, Göttingen, Deutschland
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13
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Bailey C, Murphy M, Eremin A, Weissflog W, Jákli A. Bundles of fluid fibers formed by bent-core molecules. Phys Rev E Stat Nonlin Soft Matter Phys 2010; 81:031708. [PMID: 20365752 DOI: 10.1103/physreve.81.031708] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2010] [Indexed: 05/29/2023]
Abstract
The internal structures, stability, and elastic properties of free-standing filament bundles of bent-core smectic liquid crystals are studied using polarizing microscopy, scanning electron microscopy, and a customized cantilever containing, temperature controlled heat stage for force measurements. We find that in bundles, the individual filaments fuse together to form semiseparable filaments with radii approximately two and three times larger than the individual fibers. We also find that the effective surface tension of wide bundles is about 10% smaller than a single filament. Finally, we describe the metastable coexistences of single fibers within the bundles that lead to bending of the bundles. All of these observations were explained with simple macroscopic models.
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Affiliation(s)
- C Bailey
- Chemical Physics Interdisciplinary Program and Liquid Crystal Institute, Kent State University, Kent, Ohio 44242, USA
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14
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Weissflog W, Pelzl G, Kresse H, Baumeister U, Brand K, Schröder MW, Tamba MG, Findeisen-Tandel S, Kornek U, Stern S, Eremin A, Stannarius R, Svoboda J. In search of a new design strategy for solid single-component organic ferroelectrics: Polar crystalline phases formed by bent-core molecules. ACTA ACUST UNITED AC 2010. [DOI: 10.1039/c0jm00322k] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Abstract
Abstract
The formation of particles following the photolysis of C3O2, Fe(CO)5 and Mo(CO)6, diluted with Ar or He was registered at room temperature. Particle growth was followed by taking light extinction profiles at 633nm and at 220nm for various mixture compositions and pressures. The particles obtained at different conditions were analyzed using transition electron microscope (TEM) technique. It was found that in the pure undiluted gases at the partial pressures shown in the pictures no light absorption and no particle formation could be observed. Light absorption started for partial pressures of the diluent gas > 10mbar. A comparison of particle size measured here at room temperature with data obtained at elevated temperature shows that the data obtained here fit well to the elevated temperature data.
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Abstract
Abstract
In this work the results of numerous experiments on carbon particle formation in combustion and pyrolysis of various carbon bearing molecules behind shock waves in the wide temperature range from 1200K to 3500K are analyzed. It is shown, that the discrepancy in the temperatures of the maximum particle yield could be attributed to the differences in the endothermicy of the pyrolysis of various molecules and the maximum optical density at 633nm in all mixtures can be related to the same temperture T=1600K. Based on this consideration, several statements were formulated. First – particle growth in all mixtures can be described by the uniform dependence of optical density D (at 633 nm) on time D~aτ0.4 indicating, that particle formation proceeds via homogeneous condensation. The second – decrease of the optical density at 633nm with the temperature rise is caused not by the decrease of particle yield, but the decrease of their size resulting in the fall of extinction at the given wavelength. Third – the reason of the fall of the final particle size with the temperature rise is the acceleration of the initial cluster formation process and a corresponding increase of the particle number density. And the last statement – the secondary particle growth, observed at T>2200K is completely determined by the primary clusters (nucleus) formed behind the incident wave and the coagulation of small carbon particles formed behind the reflected shock wave using these clusters.
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17
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Abstract
In this work the processes of nonequilibrium radiation and ionization in the weak shock waves (2 < M < 4) in argon or helium, containing a small admixture (0.1–2%) of Fe(CO)5 are experimentally studied. The spectra- and time-resolved measurements, performed using a ICCD camera (StreakStar II, LaVision GmbH) have shown, that the unresolved radiation spectra are situated in the range 400–700 nm. The maximum of the spectra lies approximately at 615 nm. The radiation appeared immediately at the propagating shock front and lasted about 8–12 μs. The following time-resolved measurements, performed using photomultipliers (at 615 ± 10 nm) and calibrated electric probes have shown intensive peaks of emission and electric current with duration of few μs, that correlates with the characteristic time of active growth of iron clusters. The analysis of the results obtained allowed to conclude that the real mechanism of generation of the observed peaks of radiation and ionization is the instant dissociation of Fe(CO)5 causing an active condensation process of a supersaturated vapor of iron atoms, which results in the formation of excited and ionized iron clusters.
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18
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Emelianov A, Eremin A, Fortov V, Jander H, Makeich A, Wagner HG. Detonation wave driven by condensation of supersaturated carbon vapor. Phys Rev E Stat Nonlin Soft Matter Phys 2009; 79:035303. [PMID: 19392009 DOI: 10.1103/physreve.79.035303] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2008] [Revised: 12/17/2008] [Indexed: 05/27/2023]
Abstract
An experimental observation of a detonation wave driven by the energy of condensation of supersaturated carbon vapor is reported. The carbon vapor was formed by the thermal decay of unstable carbon suboxide C3O2 behind shock waves in mixtures containing 10-30% C3O2 in Ar. In the mixture 10% C3O2+Ar the insufficient heat release resulted in a regime of overdriven detonation. In the mixture 20% C3O2+Ar measured values of the pressure and wave velocity coincident with calculated Chapman-Jouguet parameters were attained. In the richest mixture 30% C3O2+Ar an excess heat release caused the slowing down of the condensation rate and the regime of underdriven detonation was observed.
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Affiliation(s)
- A Emelianov
- Joint Institute for High Temperatures, Russian Academy of Sciences, 125412 Moscow, Russia
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19
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Findeisen-Tandel S, Schröder MW, Pelzl G, Baumeister U, Weissflog W, Stern S, Nemes A, Stannarius R, Eremin A. Multistage polar switching in bent-core mesogens. Eur Phys J E Soft Matter 2008; 25:395-402. [PMID: 18425409 DOI: 10.1140/epje/i2007-10306-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2007] [Accepted: 02/27/2008] [Indexed: 05/26/2023]
Abstract
We report a novel type of electro-optical switching in a tilted smectic phase of bent-shaped mesogens. The switching consists of a continuous stage and two bistable transitions. Detailed optical and electro-optical measurements using high-speed imaging are given and possible interpretations of the experimental results are discussed.
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Affiliation(s)
- S Findeisen-Tandel
- Martin-Luther-Universität Halle-Wittenberg, Institut für Physikalische Chemie, Halle (Saale), Germany
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20
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Stannarius R, Eremin A, Tamba MG, Pelzl G, Weissflog W. Field-induced texture transitions in a bent-core nematic liquid crystal. Phys Rev E Stat Nonlin Soft Matter Phys 2007; 76:061704. [PMID: 18233858 DOI: 10.1103/physreve.76.061704] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2006] [Revised: 11/02/2007] [Indexed: 05/25/2023]
Abstract
It is demonstrated in electro-optic experiments that an external electric field of the order of 10;{5} V/m induces persisting texture transitions in a nematic phase formed by bent-core mesogens. The field-induced metastable state is identified by its optical and electric properties. After the field is switched off, the original and induced states can coexist in domains for about one hour in planar sandwich cells. During this time, the induced domains gradually shrink but they can be stabilized in moderate electric fields. The occurrence of similar domains in homeotropic cells suggests that the transition into a metastable biaxial state is observed. In the field-free planar ground state, the formation of inversion walls is observed inside the metastable domains.
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Affiliation(s)
- R Stannarius
- Institute of Experimental Physics, Otto-von-Guericke-University, Universitätsplatz 2, D-39106 Magdeburg, Germany
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21
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Eremin A, Kuz'micheva G, Zharikov E. Compounds AMO 4( A= Ca, Sr, Ba; M= W, Mo) with scheelite structure: growth, composition, structure peculiarities. Acta Crystallogr A 2007. [DOI: 10.1107/s0108767307093737] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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22
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Tamba MG, Weissflog W, Eremin A, Heuer J, Stannarius R. Electro-optic characterization of a nematic phase formed by bent core mesogens. Eur Phys J E Soft Matter 2007; 22:85-95. [PMID: 17334690 DOI: 10.1140/epje/e2007-00015-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2006] [Indexed: 05/14/2023]
Abstract
The purpose of this paper is the demonstration that bent core nematic phases behave quantitatively and qualitatively very different from ordinary calamitic nematics in their electro-optical characteristics. We present measurements of the elastic properties from the analysis of Brochard-Leger walls that are formed during the splay Fréedericksz transition in sandwich cells. These walls possess an unusually large shape anisotropy as compared to similar structures in calamitic nematics. The wall shapes can be explained when one assumes that the bend elastic constant K(33) is one order of magnitude larger than the twist constant K(22) of the material, supposing that flexoelectricity in the description of the elastic deformations can be neglected. Further we report periodic structures above the splay Fréedericksz transition with a wave vector perpendicular to the director easy axis. They represent either a static instability or an unconventional type of electrically driven convection.
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Affiliation(s)
- M-G Tamba
- Martin-Luther-University Halle, Institute of Physical Chemistry, Mühlpforte 1, 06108, Halle, Germany
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Pelzl G, Schröder MW, Eremin A, Diele S, Das B, Grande S, Kresse H, Weissflog W. Field-induced phase transitions and reversible field-induced inversion of chirality in tilted smectic phases of bent-core mesogens. Eur Phys J E Soft Matter 2006; 21:293-303. [PMID: 17294087 DOI: 10.1140/epje/i2006-10068-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2006] [Accepted: 12/19/2006] [Indexed: 05/13/2023]
Abstract
Three homologous achiral five-ring bent-core mesogens are presented where 4-chlororesorcinol is the central core and the aromatic rings are linked by ester groups. These compounds form smectic phases with a tilted arrangement of the molecules (tilt angle approximately 45 degrees). On cooling the isotropic liquid this phase adopts a fan-like texture which shows for two homologues at relatively high electric fields ( 25-35 V microm(-1)) an antiferroelectric electro-optical response based on the collective rotation of the molecules around their long axes. At lower temperature the application of a sufficiently high electric field leads to a continuous transition into a non-birefringent texture which exhibits randomly distributed domains of opposite handedness. These domains can be reversibly switched into a state of opposite chirality by reversal of the field polarity. This switching is bistable and shows a current response typical for a ferroelectric ground state. The possible mechanism of the field-induced phase transition, of the ferroelectric switching and of the field-induced inversion of the chirality is discussed on the base of XRD, 13C- and 1H-NMR investigations, dielectric and electro-optical measurements.
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Affiliation(s)
- G Pelzl
- Institut für Physikalische Chemie, Martin-Luther-Universität Halle-Wittenberg, Mühlpforte 1, 06108, Halle (Saale), Germany
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Eremin A, Bohley C, Stannarius R. c-director relaxation around a vortex of strength +1 in free-standing smectic-C films. Eur Phys J E Soft Matter 2006; 21:57-67. [PMID: 17093894 DOI: 10.1140/epje/i2006-10046-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2006] [Accepted: 10/02/2006] [Indexed: 05/12/2023]
Abstract
The relaxation of director fields in freely suspended smectic films is studied experimentally by means of polarizing microscopy, and analyzed by solving the torque balance equation under appropriate initial and boundary conditions. We consider in particular the role of anchoring conditions of the c-director at particles and defects in the film. The structure of regular relaxation patterns allows to determine the elastic anisotropy of smectic materials. The splay elastic constant can exceed the bend constant by a factor of two and more. A remarkable consequence of this anisotropy is the stick-slip-like relaxation around a central defect of topological strength s = + 1.
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Affiliation(s)
- A Eremin
- Institut für Experimentelle Physik, Otto-von-Guericke-Universität, Universitätsplatz 2, D-39106, Magdeburg, Germany.
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Eremin A, Nádasi H, Pelzl G, Diele S, Kresse H, Weissflog W, Grande S. Paraelectric–antiferroelectric transitions in the bent-core liquid-crystalline materials. Phys Chem Chem Phys 2004. [DOI: 10.1039/b312586f] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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26
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Eremin A, Diele S, Pelzl G, Weissflog W. Field-induced switching between states of opposite chirality in a liquid-crystalline phase. Phys Rev E Stat Nonlin Soft Matter Phys 2003; 67:020702. [PMID: 12636646 DOI: 10.1103/physreve.67.020702] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2002] [Revised: 11/14/2002] [Indexed: 05/24/2023]
Abstract
A tilted smectic phase of a new achiral banana-shaped mesogen is presented. It possesses liquidlike order within the layers and appears with a fan-shaped texture. At sufficiently high electric fields, this texture can be transformed into a texture that displays a complete extinction between crossed polarizers and it forms randomly distributed chiral domains. Above a threshold these domains can be reversibly switched into a state of opposite handedness.
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Affiliation(s)
- A Eremin
- Institut für Physikalische Chemie, Martin-Luther-Universität Halle-Wittenberg, Mühlpforte 1, 06108 Halle (Saale), Germany
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Eremin A, Diele S, Pelzl G, Nádasi H, Weissflog W. Experimental evidence for Sm-CG-->Sm-CP polymorphism in fluorinated bent-shaped mesogens. Phys Rev E Stat Nonlin Soft Matter Phys 2003; 67:021702. [PMID: 12636695 DOI: 10.1103/physreve.67.021702] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2002] [Indexed: 05/24/2023]
Abstract
We report the experimental results on pure fluorinated bent-shaped mesogens showing very unusual textures and electro-optical behavior. In the view of recent publications such behavior can be explained by triclinic symmetry of the mesophase (Sm-C(G)) formed by these compounds. Based on the results of the x-ray diffraction and electro-optical investigations, we give evidence for the Sm-C(G) -->Sm-CP polymorphism.
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Affiliation(s)
- A Eremin
- Institut für Physikalische Chemie, Martin-Luther-Universität Halle-Wittenberg, Mühlpforte 1, D-06108 Halle (Saale), Germany
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Pelzl G, Eremin A, Diele S, Kresse H, Weissflog W. Spontaneous chiral ordering in the nematic phase of an achiral banana-shaped compound. ACTA ACUST UNITED AC 2002. [DOI: 10.1039/b206236d] [Citation(s) in RCA: 144] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Eremin A, Diele S, Pelzl G, Nádasi H, Weissflog W, Salfetnikova J, Kresse H. Experimental evidence for an achiral orthogonal biaxial smectic phase without in-plane order exhibiting antiferroelectric switching behavior. Phys Rev E Stat Nonlin Soft Matter Phys 2001; 64:051707. [PMID: 11735945 DOI: 10.1103/physreve.64.051707] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2001] [Indexed: 05/23/2023]
Abstract
We report unambiguous experimental evidence for an achiral orthogonal biaxial smectic-A phase which exhibits antiferroelectric switching behavior. The evidence is based on x-ray-diffraction measurements, texture observation, and the results of dielectric and electro-optical measurements.
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Affiliation(s)
- A Eremin
- Institut für Physikalische Chemie, Martin-Luther-Universität, Halle-Wittenberg, Mühlpforte 1, D-06108 Halle, Saale, Germany
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Deppe J, Emelianov A, Eremin A, Friedrichs G, Shumova V, Wagner H, Zaslonko I. Nonequilibrium Excitation of C2 Radicals during the Thermal Decomposition of C3 O2 behind Shock Waves. Z PHYS CHEM 2001. [DOI: 10.1524/zpch.2001.215.3.417] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Deppe J, Emelianov A, Eremin A, Jander H, Wagner H, Zaslonko I. High-Temperature Carbon Particle Formation and Decay in Carbon Suboxide Pyrolysis behind Shock Waves. Z PHYS CHEM 2000. [DOI: 10.1524/zpch.2000.214.1.129] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The formation of carbon particles following the pyrolysis of C
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