Physical processes during the long-time decay of the surface potential of thin films

2007 ◽  
pp. 139-142
Author(s):  
I. Chudáček ◽  
M. Marvan ◽  
D. Slavínská
Keyword(s):  
Thin Films ◽  
Surface Potential ◽  
Time Decay ◽  
Physical Processes ◽  
Long Time

scholarly journals Global small data solutions for semilinear waves with two dissipative terms

2021 ◽  
Author(s):  
Wenhui Chen ◽  
Marcello D’Abbicco ◽  
Giovanni Girardi
Keyword(s):  
Wave Equations ◽  
Space Dimension ◽  
Full Range ◽  
Small Data ◽  
Decay Estimates ◽  
Time Decay ◽  
Nonexistence Result ◽  
Derivative Type ◽  
Long Time ◽  
Dissipative Terms

AbstractIn this work, we prove the existence of global (in time) small data solutions for wave equations with two dissipative terms and with power nonlinearity $$|u|^p$$ | u | p or nonlinearity of derivative type $$|u_t|^p$$ | u t | p , in any space dimension $$n\geqslant 1$$ n ⩾ 1 , for supercritical powers $$p>{\bar{p}}$$ p > p ¯ . The presence of two dissipative terms strongly influences the nature of the problem, allowing us to derive $$L^r-L^q$$ L r - L q long time decay estimates for the solution in the full range $$1\leqslant r\leqslant q\leqslant \infty $$ 1 ⩽ r ⩽ q ⩽ ∞ . The optimality of the critical exponents is guaranteed by a nonexistence result for subcritical powers $$p<{\bar{p}}$$ p < p ¯ .

Characterization of light-erasable giant surface potential built up in evaporated Alq3 thin films

2004 ◽  
Vol 464-465 ◽  
pp. 412-415 ◽  
Author(s):  
K. Sugi ◽  
H. Ishii ◽  
Y. Kimura ◽  
M. Niwano ◽  
E. Ito ◽  
...  
Keyword(s):  
Thin Films ◽  
Surface Potential

scholarly journals Long-Time Decay to the Global Solution of the 2D Dissipative Quasigeostrophic Equation

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Jamel Benameur ◽  
Mongi Blel
Keyword(s):  
Global Solution ◽  
Time Decay ◽  
Long Time

We study the behavior at infinity in time of any global solutionθ∈C(R+,Ḣ2-2α(R2))of the surface quasigeostrophic equation with subcritical exponent2/3≤α≤1. We prove thatlim⁡t→∞∥θ(t)∥Ḣ2-2α=0. Moreover, we prove also the nonhomogeneous version of the previous result, and we prove that ifθ∈C(R+,Ḣ2-2α(R2))is a global solution, thenlim⁡t→∞∥θ(t)∥H2-2α=0.

Origin of surface potential change during ferroelectric switching in epitaxial PbTiO3 thin films studied by scanning force microscopy

2009 ◽  
Vol 94 (3) ◽  
pp. 032907 ◽  
Author(s):  
Yunseok Kim ◽  
Changdeuck Bae ◽  
Kyunghee Ryu ◽  
Hyoungsoo Ko ◽  
Yong Kwan Kim ◽  
...  
Keyword(s):  
Thin Films ◽  
Surface Potential ◽  
Scanning Force Microscopy ◽  
Potential Change ◽  
Force Microscopy ◽  
Scanning Force ◽  
Ferroelectric Switching

Superconducting Yttrium Barium Copper Oxide Thin Films Growing on the Strained Substrates

2008 ◽  
Vol 3 (4) ◽  
pp. 25-32
Author(s):  
Aleksandr V. Zakharov ◽  
Aleksandr B. Muravjev ◽  
Irina S. Pozygun ◽  
Gennadiy M. Seropyan ◽  
Sergey A. Sychev ◽  
...  
Keyword(s):  
Thin Films ◽  
Current Density ◽  
Superconducting Devices ◽  
Single Crystal Substrate ◽  
Superconducting Thin Film ◽  
Elastic Stresses ◽  
Barium Copper ◽  
Crystal Substrate ◽  
Long Time ◽  
Yttrium Barium

The article is devoted to formation of superconducting thin films on the single-crystal substrate where areas with different values of the critical current density are, that is needed for fabrication of superconducting devices. The method is based on an establishment of elastic mechanical stresses on the substrate crystal under the nanosecond focused pulsed laser irradiation. On the irradiated substrate the superconducting thin film having auxiliary elastic stresses not till the area is over the irradiated section of the substrate is grown. At the same time the critical film current density is suppressed for required values are used to fabricate Josephson junctions. Observations for a long time demonstrate superconducting transport film properties are not varied significantly during the maintenance.

scholarly journals The diversity and variability of star formation histories in models of galaxy evolution

2020 ◽  
Vol 498 (1) ◽  
pp. 430-463 ◽  
Author(s):  
Kartheik G Iyer ◽  
Sandro Tacchella ◽  
Shy Genel ◽  
Christopher C Hayward ◽  
Lars Hernquist ◽  
...  
Keyword(s):  
Star Formation ◽  
Galaxy Evolution ◽  
Time Scales ◽  
Formation Rate ◽  
Power Laws ◽  
Stellar Mass ◽  
Physical Processes ◽  
Long Time ◽  
Hydrodynamical Simulations ◽  
Star Formation Histories

ABSTRACT Understanding the variability of galaxy star formation histories (SFHs) across a range of time-scales provides insight into the underlying physical processes that regulate star formation within galaxies. We compile the SFHs of galaxies at z = 0 from an extensive set of models, ranging from cosmological hydrodynamical simulations (Illustris, IllustrisTNG, Mufasa, Simba, EAGLE), zoom simulations (FIRE-2, g14, and Marvel/Justice League), semi-analytic models (Santa Cruz SAM) and empirical models (UniverseMachine), and quantify the variability of these SFHs on different time-scales using the power spectral density (PSD) formalism. We find that the PSDs are well described by broken power laws, and variability on long time-scales (≳1 Gyr) accounts for most of the power in galaxy SFHs. Most hydrodynamical models show increased variability on shorter time-scales (≲300 Myr) with decreasing stellar mass. Quenching can induce ∼0.4−1 dex of additional power on time-scales &gt;1 Gyr. The dark matter accretion histories of galaxies have remarkably self-similar PSDs and are coherent with the in situ star formation on time-scales &gt;3 Gyr. There is considerable diversity among the different models in their (i) power due to star formation rate variability at a given time-scale, (ii) amount of correlation with adjacent time-scales (PSD slope), (iii) evolution of median PSDs with stellar mass, and (iv) presence and locations of breaks in the PSDs. The PSD framework is a useful space to study the SFHs of galaxies since model predictions vary widely. Observational constraints in this space will help constrain the relative strengths of the physical processes responsible for this variability.

Annealing Time Dependence on 1.5μm Photoluminescence of Laser-Ablated β-FeSi2

2005 ◽  
Vol 891 ◽  
Author(s):  
Shin-ichiro Uekusa ◽  
Kunitoshi Aoki ◽  
Mohammad Zakir Hossain ◽  
Tomohiro Fukuda ◽  
Noboru Miura
Keyword(s):  
Thin Films ◽  
High Temperature ◽  
Thermal Diffusion ◽  
Annealing Time ◽  
Crystal Quality ◽  
Photoluminescence Intensity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Long Time

ABSTRACTWe prepared β-FeSi2 thin-films by using a Pulsed Laser Deposition (PLD) method and succeeded to observe photoluminescence (PL) around 1.5 μm corresponding to β-FeSi2 band from the long-time and high-temperature annealed β-FeSi2 thin-films. The β-FeSi2 thin-films were ablated on Si(111) substrates heated at 550°C. After ablation, long-time and high-temperature thermal annealing was performed in order to improve the crystal-quality. Annealing times were 5, 10, 20 and 40 hrs, and annealing temperature was kept at 900 °C. Crystallinity was evaluated by an X-ray diffraction (XRD) measurement. We have observed eminent improvement on crystal-quality of β-FeSi2 thin-films. Annealed samples show (220) or (202) X-ray diffraction signals of β-FeSi2 and the full width at half maximum (FWHM) of these peaks were 0.27° although the thickness of the samples decreased with annealing time. Thermal-diffusion of Si atoms was observed from substrate to thin-films. Fe atoms in the ablated thin-films also diffused into the substrate. The relationship between the thickness of β-FeSi2 thin-films and the thermal-diffusion were investigated with rutherford backscattering (RBS) measurement. Maximum photoluminescence intensity around 1.5 μm was observed from the thickest β-FeSi2 thin-film with only 5 hrs annealing.

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