1,143 research outputs found
Kinetic equation for hydrogen-induced direct phase transformations in Y2Fe17 magnetic alloy
Model for evolution of the hydrogen-induced direct phase transformation in Y2Fe17 magnetic alloy has been proposed. It is shown that evolution process of hydrogen-induced direct phase transformation in Y2Fe17 type hard magnetic alloy is controlled by diffusion process of Fe atoms in low temperatures interval of 330β750 oC. On the base of Kolmogorov and Lyubov kinetic theory has been obtained kinetic equation that well described the isothermal kinetic diagram for this type transformation in Y2Fe17 alloy.ΠΡΠ΅Π΄Π»ΠΎΠΆΠ΅Π½Π° ΠΌΠΎΠ΄Π΅Π»Ρ Π΄Π»Ρ ΡΠ°Π·Π²ΠΈΡΠΈΡ ΠΈΠ½Π΄ΡΡΠΈΡΠΎΠ²Π°Π½Π½ΠΎΠ³ΠΎ Π²ΠΎΠ΄ΠΎΡΠΎΠ΄ΠΎΠΌ ΠΏΡΡΠΌΠΎΠ³ΠΎ ΡΠ°Π·ΠΎΠ²ΠΎΠ³ΠΎ ΠΏΡΠ΅Π²ΡΠ°ΡΠ΅Π½ΠΈΡ Π² ΠΌΠ°Π³Π½ΠΈΡΠΎΡΠ²Π΅ΡΠ΄ΠΎΠΌ ΡΠΏΠ»Π°Π²Π΅ ΡΠΈΠΏΠ° Y2Fe17. ΠΠΎΠΊΠ°Π·Π°Π½ΠΎ ΡΡΠΎ ΠΏΡΠΎΡΠ΅ΡΡ ΡΠ°Π·Π²ΠΈΡΠΈΡ ΠΈΠ½Π΄ΡΡΠΈΡΠΎΠ²Π°Π½Π½ΠΎΠ³ΠΎ Π²ΠΎΠ΄ΠΎΡΠΎΠ΄ΠΎΠΌ ΠΏΡΡΠΌΠΎΠ³ΠΎ ΡΠ°Π·ΠΎΠ²ΠΎΠ³ΠΎ ΠΏΡΠ΅Π²ΡΠ°ΡΠ΅Π½ΠΈΡ Π² ΠΌΠ°Π³Π½ΠΈΡΠΎΡΠ²Π΅ΡΠ΄ΠΎΠΌ ΡΠΏΠ»Π°Π²Π΅ ΡΠΈΠΏΠ° Y2Fe17 Π² Π½ΠΈΠ·ΠΊΠΎΡΠ΅ΠΌΠΏΠ΅ΡΠ°ΡΡΡΠ½ΠΎΠΌ ΠΈΠ½ΡΠ΅ΡΠ²Π°Π»Π΅ 330β750 oC ΠΊΠΎΠ½ΡΡΠΎΠ»ΠΈΡΡΠ΅ΡΡΡ ΠΏΡΠΎΡΠ΅ΡΡΠ°ΠΌΠΈ Π΄ΠΈΡΡΡΠ·ΠΈΠΈ Π°ΡΠΎΠΌΠΎΠ² Fe. ΠΠ° ΠΎΡΠ½ΠΎΠ²Π΅ ΠΊΠΈΠ½Π΅ΡΠΈΡΠ΅ΡΠΊΠΎΠΉ ΡΠ΅ΠΎΡΠΈΠΈ ΡΠ°Π·ΠΎΠ²ΡΡ
ΠΏΡΠ΅Π²ΡΠ°ΡΠ΅Π½ΠΈΠΉ ΠΠΎΠ»ΠΌΠΎΠ³ΠΎΡΠΎΠ²Π° ΠΈ ΠΡΠ±ΠΎΠ²Π° ΠΏΠΎΠ»ΡΡΠ΅Π½ΠΎ ΠΊΠΈΠ½Π΅ΡΠΈΡΠ΅ΡΠΊΠΎΠ΅ ΡΡΠ°Π²Π½Π΅Π½ΠΈΠ΅, Ρ
ΠΎΡΠΎΡΠΎ ΠΎΠΏΠΈΡΡΠ²Π°ΡΡΠ΅Π΅ ΠΈΠ·ΠΎΡΠ΅ΡΠΌΠΈΡΠ΅ΡΠΊΡΡ ΠΊΠΈΠ½Π΅ΡΠΈΡΠ΅ΡΠΊΡΡ Π΄ΠΈΠ°Π³ΡΠ°ΠΌΠΌΡ Π΄Π»Ρ ΠΏΡΠ΅Π²ΡΠ°ΡΠ΅Π½ΠΈΡ ΡΠ°ΠΊΠΎΠ³ΠΎ ΡΠΈΠΏΠ° Π² ΡΠΏΠ»Π°Π²Π΅ ΡΠΈΠΏΠ° Y2Fe17
A New Limit on the Antiproton Lifetime
Measurements of the cosmic ray pbar/p ratio are compared to predictions from
an inhomogeneous disk-diffusion model of pbar production and propagation within
the Galaxy, combined with a calculation of the modulation of the interstellar
cosmic ray spectra as the particles propagate through the heliosphere to the
Earth. The predictions agree with the observed pbar/p spectrum. Adding a finite
pbar lifetime to the model, we obtain the limit tau_pbar > 0.8 Myr (90 % C.L.).Comment: 13 pages, 3 encapsulated Postscript figures, uses AASTeX; accepted by
Astrophysical Journal; minor change
Luttinger-liquid-like transport in long InSb nanowires
Long nanowires of degenerate semiconductor InSb in asbestos matrix (wire
diameter is around 50 \AA, length 0.1 - 1 mm) were prepared. Electrical
conduction of these nanowires is studied over a temperature range 1.5 - 350 K.
It is found that a zero-field electrical conduction is a power function of the
temperature with the typical exponent .
Current-voltage characteristics of such nanowires are found to be nonlinear and
at sufficiently low temperatures follows the power law . It
is shown that the electrical conduction of these nanowires cannot be accounted
for in terms of ordinary single-electron theories and exhibits features
expected for impure Luttinger liquid. For a simple approximation of impure LL
as a pure one broken into drops by weak links, the estimated weak-link density
is around per cm.Comment: 5 pages, 2 figure
Towards Personalized Prostate Cancer Therapy Using Delta-Reachability Analysis
Recent clinical studies suggest that the efficacy of hormone therapy for
prostate cancer depends on the characteristics of individual patients. In this
paper, we develop a computational framework for identifying patient-specific
androgen ablation therapy schedules for postponing the potential cancer
relapse. We model the population dynamics of heterogeneous prostate cancer
cells in response to androgen suppression as a nonlinear hybrid automaton. We
estimate personalized kinetic parameters to characterize patients and employ
-reachability analysis to predict patient-specific therapeutic
strategies. The results show that our methods are promising and may lead to a
prognostic tool for personalized cancer therapy.Comment: HSCC 201
Compositional Verification for Autonomous Systems with Deep Learning Components
As autonomy becomes prevalent in many applications, ranging from
recommendation systems to fully autonomous vehicles, there is an increased need
to provide safety guarantees for such systems. The problem is difficult, as
these are large, complex systems which operate in uncertain environments,
requiring data-driven machine-learning components. However, learning techniques
such as Deep Neural Networks, widely used today, are inherently unpredictable
and lack the theoretical foundations to provide strong assurance guarantees. We
present a compositional approach for the scalable, formal verification of
autonomous systems that contain Deep Neural Network components. The approach
uses assume-guarantee reasoning whereby {\em contracts}, encoding the
input-output behavior of individual components, allow the designer to model and
incorporate the behavior of the learning-enabled components working
side-by-side with the other components. We illustrate the approach on an
example taken from the autonomous vehicles domain
Application of a superparametric finite shell element to the calculation of turbine blade vibrations
Determination of the natural frequencies and forms of vibrations of turbine blades with the present level of knowledge is one of the chief problems that have to be solved at the design stage of turbines in order to ensure vibration reliability. Greater possibilities of devising more correct mathematical models of blades and universal methods of investigating their vibrations are opened up in connection with the application of the finite element method.ΠΠ»Ρ ΡΠ°ΡΡΠ΅ΡΠ° ΠΊΠΎΠ»Π΅Π±Π°Π½ΠΈΠΉ Π»ΠΎΠΏΠ°ΡΠΎΠΊ ΡΡΡΠ±ΠΎΠΌΠ°ΡΠΈΠ½ ΡΠ»ΠΎΠΆΠ½ΠΎΠΉ Π³Π΅ΠΎΠΌΠ΅ΡΡΠΈΠΈ ΠΈΡΠΏΠΎΠ»ΡΠ·ΡΡΡ ΡΡΠΏΠ΅ΡΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΠΎΠ±ΠΎΠ»ΠΎΡΠ΅ΡΠ½ΡΠ΅ ΠΊΠΎΠ½Π΅ΡΠ½ΡΠ΅ ΡΠ»Π΅ΠΌΠ΅Π½ΡΡ
Optical properties of small polarons from dynamical mean-field theory
The optical properties of polarons are studied in the framework of the
Holstein model by applying the dynamical mean-field theory. This approach
allows to enlighten important quantitative and qualitative deviations from the
limiting treatments of small polaron theory, that should be considered when
interpreting experimental data. In the antiadiabatic regime, accounting on the
same footing for a finite phonon frequency and a finite electron bandwidth
allows to address the evolution of the optical absorption away from the
well-understood molecular limit. It is shown that the width of the multiphonon
peaks in the optical spectra depends on the temperature and on the frequency in
a way that contradicts the commonly accepted results, most notably in the
strong coupling case. In the adiabatic regime, on the other hand, the present
method allows to identify a wide range of parameters of experimental interest,
where the electron bandwidth is comparable or larger than the broadening of the
Franck-Condon line, leading to a strong modification of both the position and
the shape of the polaronic absorption. An analytical expression is derived in
the limit of vanishing broadening, which improves over the existing formulas
and whose validity extends to any finite-dimensional lattice. In the same
adiabatic regime, at intermediate values of the interaction strength, the
optical absorption exhibits a characteristic reentrant behavior, with the
emergence of sharp features upon increasing the temperature -- polaron
interband transitions -- which are peculiar of the polaron crossover, and for
which analytical expressions are provided.Comment: 16 pages, 6 figure
ELEMENTARY LINKS OF LINEAR SPATIAL RHEOLOGICAL MODEL OF ASPHALT-CONCRETE
The article deals with three-demensional mathematical models of the deformation mode of Hook, Newton, Maxwell and Kalvin elements
Diffusion and Transport Coefficients in Synthetic Opals
Opals are structures composed of the closed packing of spheres in the size
range of nano-to-micro meter. They are sintered to create small necks at the
points of contact. We have solved the diffusion problem in such structures. The
relation between the diffusion coefficient and the termal and electrical
conductivity makes possible to estimate the transport coefficients of opal
structures. We estimate this changes as function of the neck size and the
mean-free path of the carriers. The theory presented is also applicable to the
diffusion problem in other periodic structures.Comment: Submitted to PR
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