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Wyszukujesz frazę "quantum" wg kryterium: Wszystkie pola


Tytuł:
Metal-titanium oxide / quantum dot porous silicon / silicon-metal solar cell
Autorzy:
Abd, Ahmad Naji
Mishjil, Khudheir A.
Abdulsada, Ali Hamid
Habubi, N. F.
Powiązania:
https://bibliotekanauki.pl/articles/1177996.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
AFM
FTIR
TiO2
X-Ray diffraction
XRD
electrochemical etching p-type silicon wafer
nanocrystalline porous silicon
Opis:
In this paper, the nanocrystalline porous silicon (PSi) films are prepared by electrochemical etching of p-type silicon wafer with current density 7 mA/cm2 and etching times on the formation nano-sized pore array with a dimension of around different etching time. The films were characterized by the measurement of XRD, FTIR spectroscopy and atomic force microscopy properties (AFM). We have estimated crystallites size from X-Ray diffraction about nanoscale for porous silicon and Atomic Force microscopy confirms the nanometric size Chemical fictionalization during the electrochemical etching show on the surface chemical composition of PS. The etching possesses inhomogeneous microstructures that contain a-Si clusters (Si3–Si–H) dispersed in amorphous silica matrix. From the FTIR analyses showed that the Si dangling bonds of the as-prepared PS layer have large amount of Hydrogen to form weak Si–H bonds. The atomic force microscopy investigation shows the rough silicon surface, with increasing etching process (current density and etching time) porous structure nucleates which leads to an increase in the depth and width (diameter) of surface pits. Consequently, the surface roughness also increase.
Źródło:
World Scientific News; 2018, 96; 134-148
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fusion reaction study of halo system by quantum mechanical-based model for ⁶He+⁶⁴Zn, ⁸B+⁵⁸Ni and 8He+¹⁹⁷Au systems
Autorzy:
Abd Madhi, Maryam H.
Majeed, Fouad A.
Powiązania:
https://bibliotekanauki.pl/articles/2086832.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
semi-classical treatment
fusion barrier distribution
halo nuclei
fusion cross-section
continuum discretized coupled channels
półklasyczne działanie
dystrybucja bariery termojądrowej
jądro halo
przekrój fuzji
kanał sprzężony
Opis:
In the current work the calculations of the reaction cross-section of total fusion σ fus, the fusion barrier distribution D fus, and the probability P fus were achieved for systems ⁶He+⁶⁴Zn, ⁸B+⁵⁸Ni and ⁸He+¹⁹⁷Au which involve halo nuclei by using a semiclassical approach. The semiclassical and quantum mechanics treatments comprise the approximation of WKB for describing the relative motion among projectile nuclei and target nuclei, and the method of CDCC (Continuum Discretized Coupled Channel) for describing the intrinsic motion for the projectile and target nuclei. Our semiclassical calculations yielded findings that were compared to obtainable experimental data as well as quantum mechanics calculations. For fusion cross-sections σ fus below and above the Coulomb barrier Vb, the quantum mechanics coupled channels are very similar, according to the experimental results.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2021, 69, 4; e137734, 1--6
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Classification of EEG Signals Using Quantum Neural Network and Cubic Spline
Autorzy:
Abdul-Zahra Raheem, M.
AbdulRazzaq Hussein, E.
Powiązania:
https://bibliotekanauki.pl/articles/227206.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
signals
ERP signals
cubic spline
neural networks
quantum neural network
Opis:
The main aim of this paper is to propose Cubic Spline-Quantum Neural Network (CS-QNN) model for analysis and classification of Electroencephalogram (EEG) signals. Experimental data used here were taken from seven different electrodes. The work has been done in three stages, normalization of the signals, extracting the features by Cubic Spline Technique (CST) and classification using Quantum Neural Network (QNN). The simulation results showed that five types of EEG signals were classified with an average accuracy for seven electrodes that is 94.3% when training 70% of the features while with an average accuracy of 92.84% when training 50% of the features.
Źródło:
International Journal of Electronics and Telecommunications; 2016, 62, 4; 401-408
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Collective Spontaneous Emission from a System of Quantum Dots
Autorzy:
Abdussalam, W.
Machnikowski, P.
Powiązania:
https://bibliotekanauki.pl/articles/1403617.pdf
Data publikacji:
2012-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.Hc
42.50.Ct
03.65.Yz
Opis:
We study the spontaneous emission from a regular lateral array or a randomly distributed ensemble of quantum dots under strong excitation (full inversion) conditions. We focus on the similarities and differences between the cases of random and regular arrangement of the dots and show that there is very little difference between the evolution of luminescence in these two cases, both for identical dots and for a realistically inhomogeneously broadened ensemble. This means that the enhanced emission or superradiance effect is not due to accidental clustering of pairs of dots. Moreover, we point out that observation of an enhanced emission under weak excitation does not prove that true superradiance will develop in a fully inverted system.
Źródło:
Acta Physica Polonica A; 2012, 122, 6; 994-996
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Collective Spontaneous Emission from Pairs of Quantum Dots: Long-Range vs. Short-Range Couplings
Autorzy:
Abdussalam, W.
Machnikowski, P.
Powiązania:
https://bibliotekanauki.pl/articles/1492857.pdf
Data publikacji:
2011-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.Hc
42.50.Ct
03.65.Yz
Opis:
We study the spontaneous emission from a coherently delocalized exciton state in a double quantum dot as a function of the distance between the dots, focusing on the similarities and differences between the cases of radiative (long-range, dipole) and tunnel coupling between the excitons in the dots. We show that there may be no qualitative difference between the collective emission induced by these two coupling types in spite of their essentially different physical properties.
Źródło:
Acta Physica Polonica A; 2011, 120, 5; 865-867
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multi-Electrode Tapered Waveguide Structure for Quantum-Dot Semiconductor Optical Amplifiers
Autorzy:
Abedi, K.
Mohadesrad, E.
Powiązania:
https://bibliotekanauki.pl/articles/1399959.pdf
Data publikacji:
2013-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.50.-p
42.30.Lr
42.79.-e
Opis:
In this paper, by employing two practical methods of multi-electrode design and tapered waveguide structure, compensation techniques to restore declining carrier density along the quantum dot semiconductor optical amplifier's waveguide are investigated. In the multi-electrode method, the effects of distributing current via electrodes on the gain and the cross-gain modulation for two, three and four-electrode structures are studied. These characteristics are also investigated for the quantum dot semiconductor optical amplifiers with a tapered waveguide structure for the first time, including waveguides with different profiles and width ratios. After due comparison between these two methods, optimum parameters of the two techniques will be used simultaneously along each other to form a combined method. Through these design developments, gain as the main feature of the quantum dot semiconductor optical amplifiers continuously increases, though cross-gain modulator results show that there is a trade-off between the modulation efficiency and improving structure capability of restoring carrier density.
Źródło:
Acta Physica Polonica A; 2013, 123, 2; 411-414
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sub-Nanosecond Phase Recovery in Quantum-Dot Semiconductor Optical Amplifiers
Autorzy:
Abedi, K.
Taleb, H.
Powiązania:
https://bibliotekanauki.pl/articles/1399957.pdf
Data publikacji:
2013-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.Eq
78.67.-n
78.67.Hc
Opis:
In this paper, optimal design of a pumping scheme for achieving the best gain and phase response in quntum-dot semiconductor optical amplifiers is investigated. For the first time, the dynamic response of the quntum-dot semiconductor optical amplifier is evaluated under three different pumping schemes, known as optical pumping, electrical pumping, and electro-optical pumping. Simulation results show that the shortest gain recovery time in quntum-dot semiconductor optical amplifiers can be achieved under the electrical pumping scheme. However, under the optical pumping and electro-optical pumping schemes, the quntum-dot semiconductor optical amplifier represents a shorter phase recovery compared to the electrical pumping scheme. We found that a sub-nanosecond phase recovery in the quntum-dot semiconductor optical amplifier can be achieved under the OP and electro-optical pumping schemes, which can never be achieved under the electrical pumping, because of the slow carrier dynamics of the carrier reservoir. Also, it was found that the gain recovery process in an optically pumped quntum-dot semiconductor optical amplifier can be significantly accelerated at cryogenic temperatures. This result demonstrates the superiorities of the optical pumping scheme over the electrical pumping and electro-optical pumping schemes at low temperatures, where both the gain and phase recovery times of an optically pumped quantum-dot semiconductor optical amplifier are drastically decreased.
Źródło:
Acta Physica Polonica A; 2013, 123, 2; 407-410
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Peak detection unit for Free-Space-Optics receiver
Autorzy:
Achtenberg, Krzysztof
Mikołajczyk, Janusz
Szabra, Dariusz
Prokopiuk, Artur
Bielecki, Zbigniew
Powiązania:
https://bibliotekanauki.pl/articles/221334.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
peak detection
infrared receiver module for optical communications
open path laser communications
free space optics
quantum cascade laser
Opis:
The paper presents verification of a peak detection method cooperating with infrared radiation detector module applications. The work has been divided into parts including SPICE simulations and presentation of results obtained with the constructed prototype. The design of the peak detector dedicated to applications with very short pulses requires a different approach than that for standard solutions. It is mainly caused due to the ratio of pulse width and time period. In the described application this ratio is less than 10%. The paper shows testing of an analogue circuit which is capable to be inserted in these applications.
Źródło:
Metrology and Measurement Systems; 2019, 26, 2; 377-385
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transport and Capacitance Spectroscopy of Quantum Dots
Autorzy:
Adamowski, J.
Bednarek, S.
Szafran, B.
Powiązania:
https://bibliotekanauki.pl/articles/2027454.pdf
Data publikacji:
2001-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.22.-f
73.63.-b
Opis:
A review of recent theoretical studies on a single-electron tunneling in quantum dots is presented. This effect underlies the transport spectroscopy performed on the vertical gated quantum dots and the capacitance spectroscopy on the self-assembled quantum dots. The conditions of the single-electron tunneling are formulated in terms of electrochemical potentials of the electrons in the leads and in the quantum dot. The electrochemical potentials for the electrons confined in the quantum dots can be calculated by solving the many-electron Schrödinger equation. The results obtained by the Hartree-Fock method are presented. For the vertical gated quantum dot, the realistic confinement potential is obtained from the Poisson equation. The application of the self-consistent procedure to the solution of the Poisson-Schrödinger problem is discussed. The calculated positions of the current peaks at zero bias and boundaries of the Coulomb diamonds for non-zero bias are in good agreement with experiment. The influence of an external magnetic field on the single-electron tunneling is also discussed. The spin-orbital configurations of the electrons confined in the quantum dots change with the magnetic field, which leads to features observed in the current-voltage and capacitance-voltage characteristics.
Źródło:
Acta Physica Polonica A; 2001, 100, 2; 145-163
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Two-Electron Quantum Dots in Magnetic Field
Autorzy:
Adamowski, J.
Spisak, B.
Powiązania:
https://bibliotekanauki.pl/articles/1968005.pdf
Data publikacji:
1997-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.20.Dx
Opis:
A theoretical description is given for electronic properties of semiconductor quantum dots in a magnetic field. A two-electron model is applied for electrons in a cylindrical quantum dot with a parabolic confinement potential. The eigenvalue problem is solved by the variational method with the trial wave function proposed in the form of linear combination of S-type and P-type Gaussians. The energy levels of singlet and triplet states with arbitrary radial and magnetic quantum numbers have been calculated as a function of the applied magnetic field. The calculated cyclotron transition energies agree well with those measured for InGaAs/GaAs quantum dots. It is shown that the electron-electron interaction has a small influence on the transition energy.
Źródło:
Acta Physica Polonica A; 1997, 92, 4; 695-698
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Edge Switching Transformations of Quantum Graphs
Autorzy:
Aizenman, M.
Schanz, H.
Smilansky, U.
Warzel, S.
Powiązania:
https://bibliotekanauki.pl/articles/1030017.pdf
Data publikacji:
2017-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.45.Mt
02.10.Ox
Opis:
Discussed here are the effects of basics graph transformations on the spectra of associated quantum graphs. In particular it is shown that under an edge switch the spectrum of the transformed Schrödinger operator is interlaced with that of the original one. By implication, under edge swap the spectra before and after the transformation, denoted by {Eₙ}^{∞}ₙ₌₁ and {Ẽₙ}^{∞}ₙ₌₁ correspondingly, are level-2 interlaced, so that Eₙ-₂ ≤ Ẽₙ ≤ Eₙ₊₂. The proofs are guided by considerations of the quantum graphs' discrete analogs.
Źródło:
Acta Physica Polonica A; 2017, 132, 6; 1699-1703
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Collectivity and Periodic Orbits in a Chain of Interacting, Kicked Spins
Autorzy:
Akila, M.
Waltner, D.
Gutkin, B.
Braun, P.
Guhr, T.
Powiązania:
https://bibliotekanauki.pl/articles/1030009.pdf
Data publikacji:
2017-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
quantum chaos
many-body systems
semiclassics
Opis:
The field of quantum chaos originated in the study of spectral statistics for interacting many-body systems, but this heritage was almost forgotten when single-particle systems moved into the focus. In recent years new interest emerged in many-body aspects of quantum chaos. We study a chain of interacting, kicked spins and carry out a semiclassical analysis that is capable of identifying all kinds of genuine many-body periodic orbits. We show that the collective many-body periodic orbits can fully dominate the spectra in certain cases.
Źródło:
Acta Physica Polonica A; 2017, 132, 6; 1661-1665
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical MIDO : Multiple Inputs-Digital Output : device
Autorzy:
Alaiz-Gudin, Antonio M.
González-Marcos, Ana P.
Powiązania:
https://bibliotekanauki.pl/articles/2063884.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
distributed feedback laser
multi quantum well
optical bistability
semiconductor laser
Opis:
Advances in photonic technologies, with new processes and scopes of photonic integrated circuits, have generated a lot of interest as the field allows to obtain sensors with reduced size and cost and build systems with high interconnectivity and information density. In this work, answering the needs of photonic sensors that must be portable, more energy- efficient, and more accurate than their electrical counterparts, also with a view to the emerging field of neuromorphic photonics, a versatile device is presented. The proposed device makes use of the well-known advantages provided by optical bistability. By combining two distributed feedback-multi quantum well semiconductor laser structures, this new optical multiple inputs - digital output device offers various essential purposes (such as logic gates, wavelength detector and monitoring) with no need for specific manufacturing for each of them. Through a commercial computer-aided design tool, VPIphotonics™, the necessary characterization of proposed device is also described.
Źródło:
Opto-Electronics Review; 2021, 29, 4; 106--116
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
THz Spectroscopy of Extremely Shallow Acceptors States in Ge/GeSi Multiple-Quantum-Well Heterostructures
Autorzy:
Aleshkin, V. Ya.
Erofeeva, Y. V.
Gavrilenko, V. I.
Ikonnikov, A. V.
Kozlov, D. V.
Kuznetsov, O. A.
Veksler, D. B.
Powiązania:
https://bibliotekanauki.pl/articles/2041651.pdf
Data publikacji:
2005-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.Cn
76.90.+d
78.67.De
Opis:
New shallow acceptor magnetoabsorption lines in THz range have been discovered under bandgap photoexcitation in strained Ge/GeSi multiple-quantum-well heterostructures. It is shown, both theoretically and experimentally, that the resonant absorption results from the photoionization of A$\text{}^{+}$-centers and from 1s → 2p$\text{}_{+}$-type transitions from the ground state of the barrier-situated A$\text{}^{0}$-centers into excited states in the 1st and 2nd electronic subbands. The shallowest discovered ground acceptor states (E$\text{}_{B}$≤0.5 meV) are attributed to the "barrier-spaced" acceptors (a hole bound with an acceptor ion in the neighboring Ge quantum well).
Źródło:
Acta Physica Polonica A; 2005, 107, 1; 137-141
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quantum geometry of noncommutative Bernoulli shifts
Autorzy:
Alicki, Robert
Powiązania:
https://bibliotekanauki.pl/articles/1341961.pdf
Data publikacji:
1998
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Opis:
We construct an example of a noncommutative dynamical system defined over a two dimensional noncommutative differential manifold with two positive Lyapunov exponents equal to ln d each. This dynamical system is isomorphic to the quantum Bernoulli shift on the half-chain with the quantum dynamical entropy equal to 2 ln d. This result can be interpreted as a noncommutative analog of the isomorphism between the classical one-sided Bernoulli shift and the expanding map of the circle and moreover as an example of the noncommutative Pesin theorem.
Źródło:
Banach Center Publications; 1998, 43, 1; 25-29
0137-6934
Pojawia się w:
Banach Center Publications
Dostawca treści:
Biblioteka Nauki
Artykuł

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