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101.
In this paper, we will consider the higher‐order functional dynamic equations of the form on an above‐unbounded time scale , where and , . The function is a rd‐continuous function such that . The results extend and improve some known results in the literature on higher order nonlinear dynamic equations. 相似文献
102.
Said Mesloub 《Mathematical Methods in the Applied Sciences》2010,33(1):57-70
In this paper, we study a nonlocal mixed problem for a nonlinear hyperbolic equation. Based on some a priori estimates and some density arguments, we prove the well posedness of the associated linear problem. The existence and uniqueness of the weak solution of the nonlinear problem are then established by applying an iterative process based on the obtained results for the linear problem. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
103.
This paper is concerned with oscillation of the second-order quasilinear functional dynamic equation on a time scale \(\mathbb{T}\) where γ and β are quotient of odd positive integers, r, p, and τ are positive rd-continuous functions defined on \(\mathbb{T},\tau :\mathbb{T} \to \mathbb{T}\) and \(\mathop {\lim }\limits_{t \to \infty } \tau (t) = \infty \). We establish some new sufficient conditions which ensure that every solution oscillates or converges to zero. Our results improve the oscillation results in the literature when γ = β, and τ(t) ≤ t and when τ(t) > t the results are essentially new. Some examples are considered to illustrate the main results.
相似文献
$$(r(t)(x^\Delta (t))^\gamma )^\Delta + p(t)x^\beta (\tau (t)) = 0,$$
104.
Hala J. El-Khozondar Rifa J. El-Khozondar Said Zouhdi 《Applied Physics A: Materials Science & Processing》2012,109(4):865-867
The surface wave propagation at the interface between tunable metamaterials (MTMs) and nonlinear media is investigated. Tunable MTMs have a refractive index which can be tuned to negative?Czero?Cpositive values. The nonlinear media are assumed to have a Kerr-like refractive index. The dispersion equation is analytically derived and solved numerically. Results display the different behaviors of the propagating waves as the refractive index is tuned. 相似文献
105.
Waveguide electro-optic modulator in fused silica fabricated by femtosecond laser direct writing and thermal poling 总被引:3,自引:0,他引:3
An integrated electro-optic waveguide modulator is demonstrated in bulk fused silica. A Mach-Zehnder interferometer waveguide structure is fabricated by direct writing with a femtosecond laser followed by thermal poling. A 20 degrees electro-optic phase shift is achieved at an operating wavelength of 1.55 microm with an applied voltage of 400 V and an interaction length of 25.6 mm, which correspond to an estimated effective electro-optic coefficient of 0.17 pm/V for the TE-polarized mode. 相似文献
106.
Lasers operating at 1.3 μm have attracted considerable attention owing to their potential to provide efficient light sources for next-generation high-speed communication systems. InAs/GaAs quantum dots (QDs) were pointed out as a reliable low-cost way to attain this goal. However, due to the lattice mismatch, the accumulation of strain by stacking the QDs can cause dislocations that significantly degrade the performance of the lasers. In order to reduce this strain, a promising method is the use of InAs QDs embedded in InGaAs layers. The capping of the QD layer with InGaAs is able to tune the emission toward longer and controllable wave-lengths between 1.1 and 1.5 μm. In this work, using the effective-mass envelope-function theory, we investigated theoretically the optical properties of coupled InAs/GaAs strained QDs based structures emitting around 1.33 μm. The calculation was performed by the resolution of the 3D Schrödinger equation. The energy levels of confined carriers and the optical transition energy have been investigated. The oscillator strengths of this transition have been studied with and without taking into account the strain effect in the calculations. The information derived from the present study shows that the InGaAs capping layer may have profound consequences as regards the performance of an InAs/GaAs QD based laser. Based on the present results, we hope that the present work make a contribution to experimental studies of InAs/GaAs QD based structures, namely the optoelectronic applications concerning infrared and mid-infrared spectral regions as well as the solar cells. 相似文献
107.
Different ratios of phosphomolybdic acid PMA supported on silica gel (1–30 wt%) and promoted with alkali metal hydroxide have been prepared by an impregnation method and calcinated at 350 °C for 4 h. The catalysts were characterized by thermogravimetry (TG), differential thermal analysis (DTA), X-ray diffraction, FT-IR spectroscopy and N2 adsorption measurements. The surface acidity and basicity of the catalysts were determined by adsorption of pyridine and the dehydration–dehydrogenation of 2-propanol. The gas-phase esterification of acetic acid by ethanol was carried out in a conventional flow bed reactor. The results clearly revealed that among the PMA loading, the use of 10 wt% catalyst showed maximum yield of ethyl acetate. This catalyst also improved on addition of Na or K-hydroxide. These results were correlated with the structure and the acid–base properties of the prepared catalysts. 相似文献
108.
Baaziz H. Charifi Z. Reshak Ali Hussain Hamad B. Al-Douri Y. 《Applied Physics A: Materials Science & Processing》2012,106(3):687-696
The structural and electronic properties of cubic GaN
x
As1−x
with N-concentration varying between 0.0 and 1.0 with step of 0.25 were investigated using the full potential–linearized
augmented plane wave (FP-LAPW) method. We have used the local density approximation (LDA) and the generalized gradient approximation
(GGA) for the exchange and correlation potential. In addition the Engel-Vosko generalized gradient approximation (EVGGA) was
used for the band-structure calculations. The structural properties of the binary and ternary alloys were investigated. The
electronic band structure, total and partial density of states as well as the electron charge density were determined for
both the binary and their related ternary alloys. The energy gap of the alloys decreases when we move from x=0.0 to 0.25; then it increases by a factor of about 1.8 when we move from 0.25 to 0.5, 0.75 and 1.0 using EVGGA. For both
LDA and GGA moving from x=0.0 to 0.25 causes the band gap to close, showing the metallic nature of the GaN0.25As0.75 alloy. When the composition of N moves through x=0.25, 0.5, 0.75 and 1, the band gap increases. 相似文献
109.
The unsteady magnetohydrodynamic flow of a nanofluid past an oscillatory moving vertical permeable semi-infinite flat plate
with constant heat source in a rotating frame of reference is theoretically investigated. The velocity along the plate (slip
velocity) is assumed to oscillate on time with a constant frequency. The analytical solutions of the boundary layer equations
are assumed of oscillatory type and they are obtained by using the small perturbation approximations. The influence of various
relevant physical characteristics are presented and discussed. 相似文献
110.
We obtain ‘universal’ inequalities for the eigenvalues of the Laplacian acting on differential forms of a Euclidean compact
submanifold. These inequalities generalize the Yang inequality concerning the eigenvalues of the Dirichlet Laplacian of a
bounded Euclidean domain.
相似文献