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21.
A series of tungsten-tellurite glasses activated with different concentrations (0–1.5 mol %) of Er3+ has been synthesized. The structural properties of the best luminescent sample and the optical properties of its Er3+ ions, are studied both immediate after its preparation as well as after its ageing. On ageing the glass suffers structural
reorganization and generates Er2WO6—nanocrystals in the matrix, which greatly enhances the normal and upconversion green luminescence efficiency of Er3+. The nanocrystal aided enhancement of normal and upconversion luminescence of Er3+ of the glass has been attributed to the crystal field effects of the new environment of Er3+ in the nanocrystals. A phenomenon of preferential enhancement of red upconversion luminescence at the cost of green upconversion
luminescence of Er3+ at its higher concentrations in the glass has been observed and the related photo-physics is proposed. The material shows
the prospect of being used as NIR solar concentrator. 相似文献
22.
The aim in our article is to introduce the notion of statistical convergence and statistically Cauchy sequences in intuitionistic fuzzy n-normed linear spaces. The paper shows that some properties of statistical convergence of real sequences also hold for sequences in this space. Characterization for statistically convergent and statistically Cauchy sequences is also given. Further, the concept of statistical limit points and statistical cluster points are introduced and their relation with limit points of sequences have been investigated. 相似文献
23.
We have considered a model of two component mixture i.e., mixture of Chaplygin gas and barotropic fluid with tachyonic field.
In the case, when they have no interaction then both of them retain their own properties. Let us consider an energy flow between
barotropic and tachyonic fluids. In both the cases we find the exact solutions for the tachyonic field and the tachyonic potential
and show that the tachyonic potential follows the asymptotic behavior. We have considered an interaction between these two
fluids by introducing a coupling term. Finally, we have considered a model of three component mixture i.e., mixture of tachyonic
field, Chaplygin gas and barotropic fluid with or without interaction. The coupling functions decays with time indicating
a strong energy flow at the initial period and weak stable interaction at later stage. To keep the observational support of
recent acceleration we have considered two particular forms (i) Logamediate Scenario and (ii) Intermediate Scenario, of evolution
of the Universe. We have examined the natures of the recent developed statefinder parameters and slow-roll parameters in both
scenarios with and without interactions in whole evolution of the universe. 相似文献
24.
25.
Surajit Chattopadhyay Ujjal Debnath 《International Journal of Theoretical Physics》2011,50(2):315-324
Purpose of the present paper is to view the correspondence between Ricci and other dark energies. We have considered the Ricci
dark energy in presence of dark matter in non-interacting situation. Subsequently, we have derived the pressure and energy
density for Ricci dark energy. The equation of state parameter has been generated from these pressure and energy density.
Next, we have considered the correspondence between Ricci and other dark energy models, namely tachyonic field, DBI-essence
and new agegraphic dark energy without any interaction and investigated possible cosmological consequences. 相似文献
26.
Kaushik Pal Uday Narayan Maiti Tapas Pal Majumder Subhas Chandra Debnath 《Applied Surface Science》2011,258(1):163-168
A series of novel wurtzite cadmium sulphide (CdS) nanowires with uniform diameter were synthesized by using a rapid and simple solvothermal route. CdS nano structures with certain morphology could be selectively produced by only varying the concentration of poly ethylene glycol (PEG) as a surfactant in the reaction system with cadmium acetate, sulphur powder and ethelynediamine (EDA). We extensively studied UV-vis absorption spectra, photoluminescence spectra after confirming CdS nanowires with diameter 24-25 nm and length ranging up to several nano meters by field emission scanning electron microscopy (FE-SEM). Therefore we may definitely propose a new formation mechanism of CdS nanowires assisted by PEG with its illustrating optical properties. 相似文献
28.
Suresh E. Kurhade Sudhir RavulaV. Siddaiah Debnath BhuniyaD. Srinivasa Reddy 《Tetrahedron letters》2011,52(33):4313-4315
A convenient one-step method for the synthesis of novel dihydrooxazine and oxazoline based sugar hybrids is reported starting from the readily accessible sugar azides and aldehydes. We have used Aubé’s protocol to achieve this transformation. The resulting glycoconjugates could be used to increase the diversity on the sugar backbone and may find applications as potential glycomimetics and in drug discovery. 相似文献
29.
Transition Metal Chemistry - The title reaction has been studied spectrophotometrically and a rate-law established within the pH range 5.0 to 6.5, $$ {?... 相似文献
30.
Lokenath Debnath 《Meccanica》1969,4(2):122-128
Summary This paper considers the three-dimensional transient wave motions in a fluid produced by a moving oscillatory disturbance of frequency acting on the free surface of the fluid. The problem is treated as an initial value problem and is solved by the joint Laplace-Fourier transform method combined with the asymptotic treatment for the double Fourier inversion integrals. The explicit representation of the steady state as well as the transient solution of the problem is presented. It is shown that the ultimate steady is set up in the limit. A brief discussion on the principal behaviour of the wave motions is made.
Sommario Si considerano i moti ondosi transitori tridimensionali prodotti in un fluido da una eccitazione oscillatoria, in movimento, di frequenza che agisce sulla superficie libera. Il problema è trattato come problema di valori iniziali e viene risolto con il metodo della trasformata congiunta di Laplace-Fourier combinata con il trattamento asintotico per gli integrali doppi di inversione di Fourier. Si espone la rappresentazione in forma esplicita della soluzione di regime e di quella transitoria. Si dimostra che la condizione finale di regime viene stabilita nel passaggio al limite. Si esegue una breve discussione del principale comportamento del moto ondoso.相似文献