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211.
Research on Chemical Intermediates - Fe3O4-magnetized N-pyridin-4-amine-functionalized graphene oxide [Fe3O4@GO-N-(pyridin-4-amine)] was readily prepared via a three-step procedure. The synthesized... 相似文献
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213.
Research on Chemical Intermediates - Synthesis of a novel magnetic 1-naphthalenesulfonic acid-grafted graphene oxide (Fe3O4-GO-naphthalene-SO3H) via a three-step procedure has been described. The... 相似文献
214.
Research on Chemical Intermediates - In the current study, a novel acidic ionic liquid catalyst based on 8-hydroxyquinoline, namely... 相似文献
215.
An efficient method for preparation of arylaminotetrazoles is reported using natrolite zeolite as a natural catalyst. Generally, isomer of 5-arylamino-1H-tetrazole can be obtained from arylcyanamides carrying electron-withdrawing substituent on aryl ring and as the electropositivity of substituent is increased, the product is shifted toward the isomer of 1-aryl-5-amino-1H-tetrazole. This method has the advantages of high yields, simple methodology, short reaction times and easy work-up. The catalyst can be recovered by simple filtration and reused in good yields. 相似文献
216.
Non-linear vibration of a variable speed rotating beam is analyzed in this paper. The coupled longitudinal and bending vibration of a beam is studied and the governing equations of motion, using Hamilton’s principle, are derived. The solutions of the non-linear partial differential equations of motion are discretized to the time and position functions using the Galerkin method. The multiple scales method is then utilized to obtain the first-order approximate solution. The exact first-order solution is determined for both the stationary and non-stationary rotating speeds. A very close agreement is achieved between the simulation results obtained by the numerical integration method and the first-order exact solution one. The parameter sensitivity study is carried out and the effect of different parameters including the hub radius, structural damping, acceleration, and the deceleration rates on the vibration amplitude is investigated. 相似文献
217.
In this paper, the nonlinear dynamic response of an inclined pinned-pinned beam with a constant cross section, finite length
subjected to a concentrated vertical force traveling with a constant velocity is investigated. The study is focused on the
mode summation method and also on frequency analysis of the governing PDEs equations of motion. Furthermore, the steady-state
response is studied by applying the multiple scales method. The nonlinear response of the beam is obtained by solving two
coupled nonlinear PDEs governing equations of planar motion for both longitudinal and transverse oscillations of the beam.
The dynamic magnification factor and normalized time histories of mid-pint of the beam are obtained for various load velocity
ratios and the outcome results have been illustrated and compared to the results with those obtained from traditional linear
solution. The appropriate parametric study considering the effects of the linear viscous damping, the velocity of the traveling
load, beam inclination angle under zero or nonzero axial load are carried out to capture the influence of the effect of large
deflections caused by stretching effects due to the beam’s immovable ends. It was seen that quadratic nonlinearity renders
the softening effect on the dynamic response of the beam under the act of traveling load. Also in the case where the object
leaves the inclined beam, its planar motion path is derived and the targeting accuracy is investigated and compared with those
from the rigid solution assumption. Moreover, the stability analysis of steady-state response for the modes equations having
quadratic nonlinearity was carried out and it was observed from the frequency response curves that for the considered parameters
in the case of internal-external primary resonance, both saturation phenomenon and jump phenomenon can be predicted for the
longitudinal excitation. 相似文献
218.
Davood Raoufi Hamid Reza Fallah Amir Sayid Hassan Rozatian 《Applied Surface Science》2008,254(7):2168-2173
In this work, we developed the multifractality and its formalism to investigate the surface topographies of ITO thin films prepared by electron beam deposition method for various annealing temperatures from their atomic force microscopy (AFM) images. Multifractal analysis shows that the spectrum width, Δα (Δα = αmax − αmin), of the multifractal spectra, f(α), can be used to characterize the surface roughness of the ITO films quantitatively. Also, it is found that the f(α) shapes of the as-deposited and annealed films remained left hooked (that is Δf = f(αmin) − f(αmax) > 0), and falls within the range 0.149-0.677 depending upon the annealing temperatures. 相似文献
219.
Kourosh Nozari S. Davood Sadatian 《The European Physical Journal C - Particles and Fields》2008,58(3):499-510
We consider two alternative dark-energy models: a Lorentz-invariance preserving model with a non-minimally coupled scalar
field and a Lorentz-invariance violating model with a minimally coupled scalar field. We study accelerated expansion and the
dynamics of the equation of state parameter in these scenarios. While a minimally coupled scalar field does not have the capability
to be a successful dark-energy candidate with line crossing of the cosmological constant, a non-minimally coupled scalar field
in the presence of Lorentz invariance or a minimally coupled scalar field with Lorentz-invariance violation have this capability.
In the latter case, accelerated expansion and phantom divide line crossing are the results of the interactive nature of this
Lorentz-violating scenario. 相似文献
220.
Kamran Khorasani Saeid Behrouzinia Davood Salehinia 《Journal of Russian Laser Research》2008,29(6):599-603
The output power of two metal-vapor lasers is measured as functions of different buffer gasses. A copper-vapor laser and a
gold-vapor laser can be constructed using air as a buffer gas. The output power and stability of the lasers were compared
when either He or Ne or air were used as a buffer gas. The results obtained show that the output powers of the lasers are
relatively high and have fairly good stability when air was used as buffer gas. Elimination of gas handling and decrease in
the volume and weight of the laser system are the greatest advantages of the lasers elaborated. 相似文献