Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

Wyszukujesz frazę "Ghosh, S," wg kryterium: Autor


Wyświetlanie 1-10 z 10
Tytuł:
Acousto-electric interaction in magnetised piezoelectric semiconductor quantum plasma
Autorzy:
Ghosh, S.
Muley, A.
Powiązania:
https://bibliotekanauki.pl/articles/1058496.pdf
Data publikacji:
2016-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.50.+b
52.35.-g
61.72.uj
77.65.-j
Opis:
Amplification of an acoustic wave is considered in magnetised piezoelectric n-type semiconductor plasma under quantum hydrodynamic regime. The important ingredients of this study are the inclusion of quantum diffraction effect via the Bohm potential, statistical degeneracy pressure, and externally applied magnetostatic field in the momentum balance equation of the charged carriers. A modified dispersion relation is derived for evolution of acoustic wave by employing the linearization technique. Detailed analysis of quantum modified dispersion relation of acoustic wave is presented. For a typical parameter range, relevant to n-InSb at 77 K, it is found that the non-dimensional quantum parameter H reduces the gain while magnetic field enhances the gain of acoustic wave. The crossover from attenuation to amplification occurs at (ϑ₀/ϑₛ)=1 and this crossover point is found to be unaffected by quantum correction and magnetic field. It is also found that the maximum gain point shifts towards lower drift velocity regime due to the presence of magnetic field while quantum parameter H shifts this point towards higher drift velocity. Numerical results on the acoustic gain per radian and acoustic gain per unit length are also illustrated. Our results could be useful in understanding acoustic wave propagation in magnetised piezoelectric semiconductor in quantum regime.
Źródło:
Acta Physica Polonica A; 2016, 130, 6; 1401-1405
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Amplitude Modulation and Demodulation in Strain Dependent Diffusive Semiconductors
Autorzy:
Ghosh, S.
Yadav, N.
Powiązania:
https://bibliotekanauki.pl/articles/2047356.pdf
Data publikacji:
2007-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
52.35.Mw
72.50.+b
66.30.-h
Opis:
In communication processes, amplitude modulation is very helpful to save power by using a single band transmission. Thus in this paper authors have explored the possibility of amplitude modulation as well as demodulation of an electromagnetic wave in a transversely magnetized electrostrictive semiconductor. The inclusion of carrier diffusion and phenomenological damping coefficient in the nonlinear laser-semiconductor plasma interaction adds a new dimension to the analysis present in this paper. This problem is analyzed in different wave number regimes over a wide range of cyclotron frequencies. It is found that the complete absorption of the waves takes place in all the possible wavelength regimes when the cyclotron frequency (ω$\text{}_{c}$) becomes exactly equal to (ν$\text{}^{2}$+ω$\text{}_{0}^{2}$)$\text{}^{1}\text{}^{/}\text{}^{2}$ in absence of damping parameter. It has also been seen that diffusion of charge carriers modifies amplitude modulation and demodulation processes significantly. The damping parameter plays a very important role in deciding the parameter range and selecting the side band mode that will be modulated by the above-mentioned interaction.
Źródło:
Acta Physica Polonica A; 2007, 112, 1; 29-40
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dispersion and Absorption of Longitudinal Electro-Kinetic Waves in Magnetized Ion-Implanted Semiconductor Plasmas
Autorzy:
Ghosh, S.
Thakur, Preeti
Powiązania:
https://bibliotekanauki.pl/articles/2047263.pdf
Data publikacji:
2007-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
52.35.Fp
61.72.Ww
82.70.Dd
Opis:
The instability of longitudinal electro-kinetic wave that is propagating across the magnetic field B$\text{}_{0}$ in ion-implanted group-IV semiconductor sample consisting of non-drifting electrons, holes, and negatively charged colloids is investigated. Using hydrodynamic approach, a compact dispersion relation D(ω,k) is derived for the same. The propagation and amplification characteristics of the wave in collision dominated regime are studied numerically in detail for slow and fast modes. Results show that the presence of transverse magnetic field is responsible for the modification of the existing wave spectra of the slow electro-kinetic branch. In case of fast electro-kinetic wave, the presence of magnetic field is found responsible for excitation and amplification of a new mode. It is also found that the magnetic field is responsible for the conversion of two existing aperiodic modes into periodic ones. These novel periodic modes are found to be counter-propagating in nature.
Źródło:
Acta Physica Polonica A; 2007, 111, 2; 247-256
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phonon-plasmon interactions in inhomogeneous semiconductor plasma embedded with nanoparticle cluster
Autorzy:
Ghosh, S.
Dubey, P.
Powiązania:
https://bibliotekanauki.pl/articles/1050820.pdf
Data publikacji:
2018-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.30.+q
72.50.+b
73.22.Lp
Opis:
Phonon-plasmon interaction in inhomogeneous piezosemiconductor embedded with a nanoparticle cluster is examined using hydrodynamic model of plasma and macroscopic model of piezoelectric media. Present work dealt with the extensive investigation of acoustic wave amplification characteristics. The effects of density gradient δ and non-dimensional parameter l related to nanoparticle cluster on acoustic gain have been studied with varying medium electron density n_{0e}, wave frequency ω and velocity ratio ϑ_{0}/ϑ_{s}. The results so obtained, infer that the varying inhomogeneity and presence of nanoparticle cluster within the semiconductor plasma medium play decisive role in depicting the gain characteristics of acoustic wave.
Źródło:
Acta Physica Polonica A; 2018, 133, 5; 1287-1293
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Strongly Correlated Electron Behaviour in $CeT_2Al_8$ (T~=~Fe,~Co)
Autorzy:
Ghosh, S.
Strydom, A.
Powiązania:
https://bibliotekanauki.pl/articles/1427072.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.40.Cx
71.27.+a
75.30.Mb
75.20.Hr
Opis:
We report on studies of physical properties of the two compounds $CeFe_2Al_8$ and $CeCo_2Al_8$ in which we have found varying degrees of electronic correlational phenomena. No magnetic ordering was detected down to 0.4 K in either of the two compounds. At elevated temperatures an incoherent Kondo interaction between the Ce 4f-electron and the conduction electrons is prevalent in both compounds. $CeCo_2Al_8$ exhibits a stable 4f-electron magnetic moment, but in $CeFe_2Al_8$ an intermediate-valent state prevails near room temperature that eventually transforms into a Fermi-liquid ground state. The low-temperature specific heat of $CeCo_2Al_8$ shows typical strongly correlated electron behaviour and a - logT upturn in its electronic specific heat below about 10 K.
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 1082-1084
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Density Gradient on the Acousto-Electric Wave Instability in Ion-Implanted Semiconductor Plasmas
Autorzy:
Ghosh, S.
Khare, Pragati
Powiązania:
https://bibliotekanauki.pl/articles/2044639.pdf
Data publikacji:
2006-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.Vv
72.30.+q
82.70.Dd
Opis:
Using hydrodynamic model of inhomogeneous plasma, an analytical investigation of excitation of acousto-electric mode was made in n-type piezoelectric ion-implanted semiconductor plasma. By employing the multi-fluid balance equations along with the elastic and Maxwell equations, a compact dispersion relation for the cases in which colloidal grains are either stationary (ϑ$\text{}_{0d}$=0) or streaming (ϑ$\text{}_{0d}$≢0$) is derived. We find that the choice of homogeneous medium is favorable in achieving higher acoustic gain per radian and the results of the investigation should be useful in understanding the characteristics of longitudinal acousto-electric wave in ion-implanted piezoelectric semiconductor whose main constituents are electrons and negatively charged colloidal particles.
Źródło:
Acta Physica Polonica A; 2006, 109, 2; 187-197
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Parametric Amplification in Magnetized Nondegenerate Semiconducting Plasmas
Autorzy:
Jat, K. L.
Neogi, A.
Ghosh, S.
Powiązania:
https://bibliotekanauki.pl/articles/1887743.pdf
Data publikacji:
1991-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.65.Ky
72.20.Ht
73.50.Rb
78.20.Hp
Opis:
Using the straightforward coupled-mode theory, the parametric amplification is analytically investigated in magnetized piezoelectric as well as non-piezoelectric semiconductors. The origin of nonlinear interaction is taken to be in the second-order optical susceptibility χ$\text{}^{(2)}$ arising from the nonlinear induced current density. The threshold value of the pump electric field E$\text{}_{0th}$ is obtained for crystals. E$\text{}_{0th}$ is found to decrease with the rise in magnetic field and fall with the rise in scattering angle. Parametric gain constants are obtained for different situations of practical interest, i.e. (i) for piezoelectric coupling only g$\text{}_{p}$, (ii) for deformation potential coupling only g$\text{}_{d}$, (iii) for both the couplings g$\text{}_{b}$. Numerical investigations reveal that the magnetic field increases the gain. Maximum gains are obtained for backward scattered mode. g$\text{}_{d}$ is always found to be less than g$\text{}_{p}$ and g$\text{}_{b}$. It is also found that g$\text{}_{p}$ and g$\text{}_{b}$ both are identical up to k ≈ x 10$\text{}^{7}$m$\text{}^{-1}$ and for k ≥ 3 x 10$\text{}^{7}$m$\text{}^{-1}$, g$\text{}_{b}$ exceeds g$\text{}_{p}$.
Źródło:
Acta Physica Polonica A; 1991, 79, 6; 829-841
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Crystal Field Theory of Magnetic Behaviour of Er$\text{}_{2}$(SO$\text{}_{4}$)$\text{}_{3}$·8H$\text{}_{2}$O
Autorzy:
Gupta, R.
Ghosh, U. S.
Basu, C.
Powiązania:
https://bibliotekanauki.pl/articles/1945413.pdf
Data publikacji:
1996-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.70.Ch
75.10.Dg
Opis:
Using the most rigorous approach of direct diagonalization of the Hamiltonian matrix constructed in the complete basis states (364 in number) of the Er$\text{}^{3+}$ ion the observed magnetic susceptibility and anisotropy data of erbium sulphate octahydrate were simulated and the set of crystal field parameters was evaluated. This procedure automatically includes the effect of intermediate coupling and the J-mixing under the crystal field. It was also demonstrated that such rigorous calculation using complete basis states is necessary in order to evaluate the correct set of parameters which may widely differ from the values obtained from approximate calculations previously performed using partial number of basis states of the ion concerned.
Źródło:
Acta Physica Polonica A; 1996, 89, 5-6; 649-655
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Exact Phase and its Eikonal Approximation for Class of Reflectionless Index Profiles
Autorzy:
Sharma, S. K.
Ghosh, G.
Powiązania:
https://bibliotekanauki.pl/articles/1963260.pdf
Data publikacji:
1997-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.25.Fx
41.20.Jb
Opis:
We examine the problem of transmission of electromagnetic waves in a multiparameter reflectionless dielectric. It is shown that it is possible to obtain an analytic form for the phase of the exact transmission amplitude. In the high frequency limit the exact result is found to lead to the eikonal approximation. Interestingly, the high frequency limit and long-range approximation required for the validity of the eikonal approximation are not independent here.
Źródło:
Acta Physica Polonica A; 1997, 91, 3; 555-561
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nonlinear Ion-Acoustic Waves in Gravitating Dusty Plasma with Non-Isothermal Electrons and Fluctuating Dust Charges
Autorzy:
Paul, S.
Pakira, G.
Paul, B.
Ghosh, B.
Powiązania:
https://bibliotekanauki.pl/articles/1419744.pdf
Data publikacji:
2012-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
52.27.Lw
52.35.Fp
04.40.-b
Opis:
Using the reductive perturbation method a theoretical infrastructure has been developed to study the nonlinear propagation of ion-acoustic waves in self-gravitating multicomponent dusty plasma consisting of positive ions, non-isothermal electrons and negatively charged warm dust particles with fluctuating dust charges and drifting motion. It is shown that instead of coupled nonlinear equations as obtained by earlier authors the nonlinear propagation of ion-acoustic waves in such a plasma can be described by an uncoupled third order partial differential equation which is a modified form of the Korteweg-de Vries equation. From this equation, quasi-soliton solution is obtained for the ion-acoustic wave. The effects of non-isothermal electrons, gravity, dust charge fluctuations and drifting motion on the ion-acoustic solitary waves are discussed with application in astrophysical contexts. The importance of the model considered here has also been pointed out.
Źródło:
Acta Physica Polonica A; 2012, 122, 1; 116-121
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-10 z 10

    Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies