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161 results on '"Frenkel, Y"'

1. Propagation of extremely short electromagnetic pulses in a doubly-resonant medium

Author

Frenkel, Y., Gabitov, I., Maimistov, A., and Roytburd, V.

Subjects
Nonlinear Sciences - Pattern Formation and Solitons, Nonlinear Sciences - Exactly Solvable and Integrable Systems
Abstract

Propagation of extremely short electromagnetic pulses in a homogeneous doubly-resonant medium is considered in the framework of the total Maxwell-Duffing-Lorentz model, where the Duffing oscillators (anharmonic oscillators with cubic nonlinearities) represent the dielectric response of the medium, and the Lorentz harmonic oscillators represent the magnetic response. The wave propagation is governed by the one-dimensional Maxwell equations. It is shown that the model possesses a one-parameter family of traveling-wave solutions with the structure of single or multiple humps. Solutions are parametrized by the velocity of propagation. The spectrum of possible velocities is shown to be continuous on a small interval at the lower end of the spectrum; elsewhere the velocities form a discrete set. A correlation between the number of humps and the velocity is established. The traveling-wave solutions are found to be stable with respect to weak perturbations. Numerical simulations demonstrate that the traveling-wave pulses collide in a nearly elastic fashion.

Published
2008

2. On the behavior of liquid drops on a solid surface. 1. The sliding of drops on an inclined surface

Author

Frenkel, Y. I.

Subjects
Physics - Fluid Dynamics, Physics - Chemical Physics
Abstract

The idea of contact angle was generalized by using the principle of minimum total energy. The problems of the shape of the two-dimensional sessile drop and the drop on an inclined surface are considered. The differential equations describing the drop shapes are found in both cases. A case of good wetting is considered to determine the profiles of the sessile and inclined drops. The generalization of the boundary conditions for the contact angle hysteresis of the drop on an inclined surface is discussed. The limit of the inclination angle at which the drop begins to run down the inclined plane is found. The models of the drop detachment from the solid and the motion of liquid inside of the drop are discussed. This is not an original text., Comment: The original Russian article was translated by Viatcheslav Berejnov

Published
2005

4. Contributors

Author

Amoruso, S., primary, Baiutti, F., additional, Balke, N., additional, Bäumer, C., additional, Chen, Y.Z., additional, Chen, C., additional, Chiabrera, F., additional, Christiani, G., additional, Chroneos, A., additional, Datta, A., additional, Dittmann, R., additional, Eichel, R.-A., additional, Fluri, A., additional, Frenkel, Y., additional, Garbayo, I., additional, Hansen, K.V., additional, Harrington, G.F., additional, Huijben, M., additional, Kalisky, B., additional, Kar-Narayan, S., additional, Koster, G., additional, Lee, H.N., additional, Logvenov, G., additional, Lu, Y., additional, Mukherjee, D., additional, Nichols, J., additional, Notten, P.H.L., additional, Ohta, H., additional, Pergolesi, D., additional, Perry, N.H., additional, Rijnders, G., additional, Rupp, J.L.M., additional, Schneider, C.W., additional, Schweiger, S., additional, Sing, M., additional, Son, J.-W., additional, Tarancón, A., additional, Tselev, A., additional, Tuller, H.L., additional, Wrobel, F., additional, and Zhong, Z., additional

Published
2018
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11. Strain-tunable magnetism at ferroelastic domain walls

Author

Christensen, D. V., Frenkel, Y., Xie, Y., Chen, Z., Hikita, Y., Smith, A., Chen, Y. Z., Klein, L., Hwang, H. Y., Pryds, N., Kalisky, B., Christensen, D. V., Frenkel, Y., Xie, Y., Chen, Z., Hikita, Y., Smith, A., Chen, Y. Z., Klein, L., Hwang, H. Y., Pryds, N., and Kalisky, B.

Abstract

Applying stress to a ferroelastic material results in a nonlinear strain response as domains of different orientations mechanically switch. The ability to write, erase and move domain walls between such ferroelastic domains suggests a method for making nanoelectronics where the domain wall is the device. However, little is known about the magnetic properties of such domain walls. A fascinating model system is SrTiO3, where the ferroelastic domain walls display strain-tunable polarity and enhanced conductivity. Here, we reveal a long-range magnetic order with modulations along the ferroelastic domain walls in SrTiO3 and SrTiO3-based heterointerfaces, which manifests itself as a striped pattern in scanning superconducting quantum interference device maps of the magnetic landscape. In conducting interfaces, the magnetism is coupled to itinerant electrons with clear signatures in magnetotransport measurements. The magnetic state is also coupled dynamically to the lattice and can be reversibly tuned by applying local external forces. This study raises the possibility of designing nanoscale devices based on domain walls where strain-tunable ferroelectric, ferroelastic and ferromagnetic orders may coexist.

Published
2019

12. Electron Mobility in γ-Al2O3/SrTiO3

Author

Christensen, Dennis Valbjørn, Frenkel, Y., Schütz, P., Trier, Felix, Wissberg, S., Claessen, R., Kalisky, B., Smith, A., Chen, Y. Z., and Pryds, Nini

Abstract

One of the key issues in engineering oxide interfaces for electronic devices is achieving high electron mobility. SrTiO3-based interfaces with high electron mobility have gained a lot of interest due to the possibility of combining quantum phenomena with the many functionalities exhibited by SrTiO3. To date, the highest electron mobility (140 000 cm2/V s at 2 K) is obtained by interfacing perovskite SrTiO3 with spinel γ-Al2O3. The origin of the high mobility, however, remains poorly understood. Here, we investigate the scattering mechanisms limiting the mobility in γ-Al2O3/SrTiO3 at temperatures between 2 and 300 K and over a wide range of sheet carrier densities. For T>150 K, we find that the mobility is limited by longitudinal optical phonon scattering. For large sheet carrier densities (>8×1013 cm−2), the screened electron-phonon coupling leads to room-temperature mobilities up to μ∼12 cm2/V s. For 5 K

Published
2018
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13. Strain-tunable magnetism at oxide domain walls

Author

Christensen, D. V., primary, Frenkel, Y., additional, Chen, Y. Z., additional, Xie, Y. W., additional, Chen, Z. Y., additional, Hikita, Y., additional, Smith, A., additional, Klein, L., additional, Hwang, H. Y., additional, Pryds, N., additional, and Kalisky, B., additional

Published
2018
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14. Electron Mobility in γ−Al2O3/SrTiO3

Author

Christensen, D. V., primary, Frenkel, Y., additional, Schütz, P., additional, Trier, F., additional, Wissberg, S., additional, Claessen, R., additional, Kalisky, B., additional, Smith, A., additional, Chen, Y. Z., additional, and Pryds, N., additional

Published
2018
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19. Optical Study of Tetragonal Domains in LaAlO3/SrTiO3

Author

Erlich, Z., primary, Frenkel, Y., additional, Drori, J., additional, Shperber, Y., additional, Bell, C., additional, Sato, H. K., additional, Hosoda, M., additional, Xie, Y., additional, Hikita, Y., additional, Hwang, H. Y., additional, and Kalisky, B., additional

Published
2014
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21. Autonomous Attitude Determination System (AADS). Volume 1: System description

Author

Saralkar, K, Frenkel, Y, Klitsch, G, Liu, K. S, Lefferts, E, Tasaki, K, Snow, F, and Garrahan, J

Subjects
Computer Programming And Software
Abstract

Information necessary to understand the Autonomous Attitude Determination System (AADS) is presented. Topics include AADS requirements, program structure, algorithms, and system generation and execution.

Published
1982

22. Theory of reversible and nonreversible cracks in solids

Author

Frenkel, Y I

Abstract

The Griffith crack theory is reviewed and certain shortcomings of this theory are discussed. A new description for the shape of a crack is given which takes into account the atomic structure of material. Through consideration of the total energy of the system and the shape of the crack, expressions for crack behavior are derived which are considered to remedy the defects of the Griffith theory.

Published
1955

23. Optical Study of Tetragonal Domains in LaAlO/SrTiO.

Author

Bell, C., Hwang, H., Erlich, Z., Frenkel, Y., Shperber, Y., Kalisky, B., Drori, J., Sato, H., Hosoda, M., Xie, Y., and Hikita, Y.

Subjects
LANTHANUM compounds, POLARIZATION microscopy, SUPERCONDUCTING quantum interference devices, FERROMAGNETIC materials, MAGNETIC domain, PHASE separation
Abstract

Scanning superconducting quantum interference device (SQUID) measurements recently revealed enhanced channels of conductivity at the conducting LaAlO/SrTiO (LAO/STO) interface (Kalisky et al. Nat. Mater. 12, 1091 2013). The orientation of the channels and their thermal behavior suggest that they originate as a consequence of the STO tetragonal domain formation which sets in below ∼105 K. In this work, we use polarized light microscopy to acquire images of the tetragonal domains in the same group of LAO/STO samples. We looked at the configuration of the domains (orientation and spacing) and followed their behavior as a function of temperature and back-gate voltage. The optical data agrees with the electrical behavior mapped magnetically. This direct and independent study of the domain structure confirms that the channel-like conductivity in LAO/STO is due to the STO tetragonal domain structure and emphasizes the importance of STO physics to the interfacial properties. These results demonstrate how small structural changes in perovskite crystals strongly influence the electronic characteristics of heterostructures. [ABSTRACT FROM AUTHOR]

Published
2015
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42. The best donor.

Author

Shulman, A, Frenkel, Y, Dor, J, Levran, D, Shiff, E, and Maschiach, S

Subjects
INFERTILITY treatment, BIRTH rate, COMPARATIVE studies, EMBRYO transfer, FERTILIZATION in vitro, RESEARCH methodology, EVALUATION of medical care, MEDICAL cooperation, PREGNANCY, RESEARCH, EVALUATION research, OVUM donation
Abstract

Oocyte donation has become a common treatment modality for a large spectrum of infertility conditions. The purpose of this study was to assess the success rate of a shared egg donation programme, and to define the profile of a successful 'donor-recipient' couple in view of the limitations imposed by the shared programme. The results of all consecutive cycles of egg donation from 1st January 1995 to 31st December 1996 were analysed. A total of 383 donor cycles were matched with 946 recipient cycles; clinical pregnancy rates were 23. 5 and 16.7% respectively. With the exception of endometriosis, which significantly reduced the pregnancy rate in both groups, similar pregnancy rates were obtained in both groups for all the other infertility aetiologies of the donors. The donor's age had no impact on pregnancy rate of the recipient, but pregnancy rate was significantly decreased in donors >35 years. Recipients >50 years had significantly reduced pregnancy rates and those >45 years a significantly increased abortion rate. Recipients with severe male factor infertility, who had intracytoplasmic sperm injection treatment, showed pregnancy rates equivalent to those recipients who had regular in-vitro fertilization. We conclude that in a shared egg donation programme, the recipients' pregnancy rate and outcome are dependent only on the donors' infertility aetiologies and on recipients' ages. [ABSTRACT FROM AUTHOR]

Published
1999
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45. Concentration and pH Dependent Aggregation of Hydrophobic Drug Molecules and Relevance to Oral Bioavailability

Author

Frenkel, Y. V., Clark, A. D., Jr., Das, K., Wang, Y.-H., Lewi, P. J., Janssen, P. A. J., and Arnold, E.

Abstract

We have examined selected physicochemical properties of compounds from the diaryltriazine/diarylpyrimidine (DATA/DAPY) classes of non-nucleoside reverse transcriptase inhibitors (NNRTIs) and explored possible correlations with their bioavailability. In simple aqueous solutions designed to mimic the gastrointestinal (GI) environment of a fasting individual, all NNRTIs demonstrated formation of aggregates as detected by dynamic light scattering and electron microscopy. Under various conditions mimicking physiological transitions in the GI environment, aggregate size distributions were shown to depend on compound concentration and pH. NNRTIs with good absorption were capable of forming aggregates with hydrodynamic radii of ≤100 nm at higher concentrations and over wide ranges of pH, while poorly absorbed inhibitors form aggregates with radii of ≥250 nm at concentrations above 0.01 mM, probably representing precipitate. We propose a model in which the uptake rate into systemic circulation depends on having hydrophobic drug aggregates of appropriate size available for absorption at different locations within the GI tract.

Published
2005

46. In Search of a Novel Anti-HIV Drug:  Multidisciplinary Coordination in the Discovery of 4-[[4-[[4-[(1E)-2-Cyanoethenyl]-2,6-dimethylphenyl]amino]-2- pyrimidinyl]amino]benzonitrile (R278474, Rilpivirine)

Author

Janssen, P. A. J., Lewi, P. J., Arnold, E., Daeyaert, F., Jonge, M. de, Heeres, J., Koymans, L., Vinkers, M., Guillemont, J., Pasquier, E., Kukla, M., Ludovici, D., Andries, K., Bethune, M.-P. de, Pauwels, R., Das, K., Clark, A. D., Jr., Frenkel, Y. V., Hughes, S. H., Medaer, B., Knaep, F. De, Bohets, H., Clerck, F. De, Lampo, A., Williams, P., and Stoffels, P.

Abstract

Ideally, an anti-HIV drug should (1) be highly active against wild-type and mutant HIV without allowing breakthrough; (2) have high oral bioavailability and long elimination half-life, allowing once-daily oral treatment at low doses; (3) have minimal adverse effects; and (4) be easy to synthesize and formulate. R278474, a new diarylpyrimidine (DAPY) non-nucleoside reverse transcriptase inhibitor (NNRTI), appears to meet these criteria and to be suitable for high compliance oral treatment of HIV-1 infection. The discovery of R278474 was the result of a coordinated multidisciplinary effort involving medicinal chemists, virologists, crystallographers, molecular modelers, toxicologists, analytical chemists, pharmacists, and many others.

Published
2005

50. Successful pregnancy in a woman with cyanotic congenital heart disease after a palliative pulmonary-systemic shunt. A case report

Author

Frenkel Y, Menachem Alcalay, Chayen B, Blieden L, Mashiach S, and Battler A

Subjects
Adult, Heart Septal Defects, Ventricular, Fetal Growth Retardation, Transposition of Great Vessels, Palliative Care, Pregnancy Complications, Cardiovascular, Pregnancy Outcome, Pulmonary Valve Stenosis, Hemoglobins, Pregnancy, Pulmonary Atresia, Hypertension, Humans, Abnormalities, Multiple, Female, Fetal Monitoring
Abstract

A 20-year-old woman with cyanotic congenital heart disease composed of corrected transposition of the great vessels, severe pulmonic stenosis, atresia of the left pulmonary artery and a large ventricular septal defect, had a successful pregnancy following a pulmonary-systemic shunt (Blalock-Taussig). The hemoglobin decreased from 21 to 16 g/dL following the operation. The antepartum course was complicated by intrauterine growth retardation and pregnancy-induced hypertension. A normal fetal nonstress test and biophysical profile permitted continuation of the pregnancy until 38 weeks' gestation, with delivery of a healthy infant.

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