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Wyszukujesz frazę "La" wg kryterium: Temat


Tytuł:
Exact diagonalization approach for atomistic calculation of piezoelectric effects in semiconductor quantum dots
Autorzy:
Świderski, M.
Zieliński, M.
Powiązania:
https://bibliotekanauki.pl/articles/1075363.pdf
Data publikacji:
2016-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.21.La
Opis:
We present an exact diagonalization approach for atomistic calculation of excitonic properties of semiconductor nanostructures under piezoelectric field. The method allows for efficient treatment of both single particle and many-body states at a small computational cost and results in a very good agreement with the full diagonalization treatment. We illustrate our approach by analyzing the effect of a piezoelectric field on a spectra of a self-assembled InAs/GaAs lens-shaped quantum dot. We study the influence of linear and quadratic piezoelectric terms on the quantum dot electronic structure and importantly we found that the non-linear, density functional based theory of piezoelectricity produces results very similar to those obtained by a well-established linear approach utilizing empirical parameters.
Źródło:
Acta Physica Polonica A; 2016, 129, 1a; A-79-A-82
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanism of rhabdophane-(La) and lanthanite-(La) formation during reduction of bioavailabe nutrients in water based on SEM and XRD study
Autorzy:
Szopa, K.
Banasik, K.
Krzykawski, T.
Powiązania:
https://bibliotekanauki.pl/articles/100842.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet Śląski. Wydział Nauk o Ziemi
Tematy:
rabdofan-(La)
lantanit-(La)
bentonit
jony fosforanowe
jony węglanowe
zbiornik wodny
rhabdophane-(La)
lanthanite-(La)
bentonite
phosphorus ion
carbonate ion
water reservoir
Opis:
This study presents results of SEM and XRD investigation of products formed after La-rich bentonite application into water containing PO43- and CO32- ions. The main product of the investigated reaction with phosphate and carbonate anions is rabdophane-(La) and lanthanite-(La), respectively. Studied material has adaptation in many water reservoirs only for phosphorus ions reduction. Further studies might find application in case of reduction others hazardous ions. They could be precipitated in the same fast and effective way, to other stable, nontoxic mineral phases.
Niniejszy artykuł traktuje o możliwości redukcji nutrientów (np. PO43-, CO32-) za pomocą bentonitu wzbogaconego w lantan. Jak dotąd jedynym zastosowaniem wspomnianego bentonitu jest redukcja jonów fosfonowych w środowiskach wodnych (np. jeziora, rzeki, zastoiska) do stabilnego i nietoksycznego związku mineralnego jakim jest rabdofan-(La). Na podstawie analiz SEM oraz XRD wykazano, że badany materiał umożliwia również redukcję jonów węglanowych do stabilnej i nietoksycznej fazy mineralnej-węglanowej (lantanit-(La)). Dalsze studia nad bentonitem lantanowym, poczynione względem innych, niepożądanych jonów (np. jonów azotanowych czy arsenianowych) mogą przynieść odpowiedzi względem ewentualnego i dalszego, środowiskowego zastosowania bentonitu lantanowego.
Źródło:
Contemporary Trends in Geoscience; 2012, 1, 1; 99-102
2299-8179
Pojawia się w:
Contemporary Trends in Geoscience
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Movement or stabilization? The Upper San River basin in the second half of the 1st millennium BC
Autorzy:
Bochnak, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/2042460.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego
Tematy:
La Tène culture
celtic culture
middle La Tène
San basin
brine springs
Opis:
The ‘Celtic episode’ of the prehistoric Sanok region should be associated with a group of colonists from the south who, during phase LT C, used the local brine springs to produce salt and supply it to the population of the Upper Tisa River basin. For now, no finds definitely associated with phases LT B or LT D have been discovered in the region. The settlers probably relied on both agriculture and animal husbandry to sustain their communities. It seems unlikely they were able to produce any food surpluses, considering the unfavourable climate and poor soil conditions. When the expansion of Dacian tribes to the south of the Carpathians began to cause shifts in the political landscape and the trade routes’ network, the San River Valley cultural centre lost its economic significance and entered a period of decline. Presumably, some of the population may have migrated north into the more fertile lands, while others might have returned to the areas of their origin. According to the available data, there seems to be no clear continuity between the La Tène occupation and the oldest Przeworsk culture finds dated to the end of the early pre-Roman period.
Źródło:
Acta Archaeologica Carpathica; 2019, 54; 25-56
0001-5229
2719-4841
Pojawia się w:
Acta Archaeologica Carpathica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spin-Dependent Coupling of Charged Quantum Dot Excitons with Continuum States
Autorzy:
Urbaszek, B.
Warburton, R. J.
Karrai, K.
Schulhauser, C.
Högele, A.
McGhee, E. J.
Govorov, A. O.
Gerardot, B. D.
Marie, X.
Amand, T.
Petroff, P. M.
Powiązania:
https://bibliotekanauki.pl/articles/2038350.pdf
Data publikacji:
2004-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.21.La
78.67.Hc
Opis:
Magnetic field and temperature dependent photoluminescence studies on neutral and charged excitons in individual InAs quantum dots allow us to uncover different mechanisms by which the discrete quantum dot states are coupled to delocalized continuum states in a quantum well (the wetting layer). The behaviour of the neutral and singly charged excitons can be explained taking only discrete quantum dot states into account. For doubly and triply charged excitons we have to consider spin dependent coherent and incoherent interactions between discrete quantum dot states and delocalized wetting layer states.
Źródło:
Acta Physica Polonica A; 2004, 106, 3; 395-402
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Influence of Tool Tilt Angle on 1050 Aluminum Lap Joint in Friction Stir Welding Process
Autorzy:
Barlas, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1031715.pdf
Data publikacji:
2017-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.20.Vj
87.15.La
Opis:
In this paper, the effect of tool tilt angle on tensile-shear failure load and weld zone properties for 1050 aluminum plates, welded by friction stir lap welding, were investigated. For this purpose, tool tilt angle was varied from 0° to 5° under the constant other parameters, such as tool geometry, tool rotation speed of 1200 rpm and tool travel speed of 30 mm/min. The tensile-shear test was employed to test the mechanical properties of the joint. Optical microscope examinations, microhardness and temperature measurements were also performed in weld zone of lap joints. According to overall results, the tool tilt angle has a reasonable influence on the joint soundness and weld defect formation. If the tool axis was perpendicular to plate surface or a larger tool tilt angle was used, such configurations had harmful effect for the weld zone. In such case the tensile-shear failure load dropped from 4853 N to 2799 N. Recorded peak temperatures varied from 381°C to 438°C in the weld center. The measured mean hardness values of the stir and heat-affected zones were 31.5 HV and 28.3 HV, respectively, which are lower than that of aluminum 1050 base metal (40.7 HV).
Źródło:
Acta Physica Polonica A; 2017, 132, 3; 679-681
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Magnetic Field on Dark States in Transport through Triple Quantum Dots
Autorzy:
Wrześniewski, K.
Weymann, I.
Powiązania:
https://bibliotekanauki.pl/articles/1032454.pdf
Data publikacji:
2017-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.-b
73.21.La
Opis:
We theoretically study the electronic transport through a triple quantum dot system in triangular geometry weakly coupled to external metallic leads. By means of the real-time diagrammatic technique, the current and Fano factor are calculated in the lowest order of perturbation theory. The device parameters are tuned to such transport regime, in which coherent population trapping of electrons in quantum dots due to the formation of dark states occurs. The presence of such states greatly influences transport properties leading to a strong current blockade and enhanced, super-Poissonian shot noise. We consider both one- and two-electron dark states and examine the influence of magnetic field on coherent trapping in aforementioned states. When the system is in one-electron dark state, we observe a small shift of the blockade's region, whereas in the case of two-electron dark state, we show that strong magnetic field can lift the current blockade completely.
Źródło:
Acta Physica Polonica A; 2017, 132, 1; 108-111
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of retrapping on thermoluminescence peak intensities of small amorphous silicon quantum dots
Autorzy:
Debelo, N.
Dejene, F.
Mal'nev, V.
Senbeta, T.
Mesfin, B.
Roro, K.
Powiązania:
https://bibliotekanauki.pl/articles/1070477.pdf
Data publikacji:
2016-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.21.La
73.63.Kv
Opis:
The effect of retrapping on thermoluminescence intensity peak corresponding to each trap of small amorphous silicon quantum dots in three traps - one recombination center model is investigated. For first order kinetics, where there is no effect of retrapping, the thermoluminescence intensity clearly depends on the level of the trap beneath the edge of the conduction band. This energy difference between the edge of the conduction band and the level of the trap is called trap depth (activation energy). The shallowest trap gives the highest thermoluminescence intensity peak for first order kinetics. However, it was clearly observed that for second order and a case beyond second order kinetics, the thermoluminescence intensity peak corresponding to each trap does not depend on the trap depth. In this case, the retrapping probability coefficients are taken into account and most electrons which are detrapped from the shallow trap(s) will be retrapped to the deeper trap(s) resulting in fewer electrons taking part in the recombination process. This significantly reduces the thermoluminescence intensity peaks of the shallower trap(s). It was observed that the deepest trap, with very high concentration of electrons due to the retrapping phenomenon, gives the highest thermoluminescence intensity. In addition, the variation of concentration of electrons in each trap and the intensity of the thermoluminescence are presented. Though we considered the model of three traps and one recombination center, this phenomenon is true for any multiple traps.
Źródło:
Acta Physica Polonica A; 2016, 129, 3; 362-366
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Energy Band and Absorption Coefficient of Quantum Dots in a Well Structure
Autorzy:
Zhang, P.
Lu, X.
Zhang, C.
Yao, J.
Powiązania:
https://bibliotekanauki.pl/articles/1419887.pdf
Data publikacji:
2012-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.21.La
73.63.Kv
Opis:
Building on the effective-mass envelope function theory, this paper focuses on the study of the energy band and the absorption coefficient of $InAs//In_{x}Ga_{1 - x}As$ quantum dots in a well (DWELL) structure. In contrast to $InAs//In_{0.15}Ga_{0.85}As$ quantum DWELL, the $InAs//In_{0.2}Ga_{0.8}As$ quantum DWELL has lower ground states. With the thickness of $In_{0.15}Ga_{0.85}As$ layer changing from 7 nm to 9 nm and $In_{0.2}Ga_{0.8}As$ layer changing from 9 nm to 12 nm, the calculation shows that their absorption coefficient spectra takes a red shift in the long-wave infrared and far-infrared ranges, respectively. Moreover, when the thickness of the $In_{x}Ga_{1 - x}As$ layer is defined as 9 nm, the absorption coefficient spectra of $InAs//In_{0.2}Ga_{0.8}As$ DWELL shows a obvious red shift comparing with that of $InAs//In_{0.15}Ga_{0.85}As$ DWELL.
Źródło:
Acta Physica Polonica A; 2012, 122, 1; 197-201
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Binding Energy of the Hydrogenic Impurity in CdTe/ZnTe Spherical Quantum Dot
Autorzy:
Stojanović, D.
Kostić, R.
Powiązania:
https://bibliotekanauki.pl/articles/1503269.pdf
Data publikacji:
2011-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.21.La
71.55.-i
Opis:
Binding energy of a hydrogenic impurity located at the center of the CdTe/ZnTe spherical quantum dot has been calculated under the effective mass approximation by solving Schrödinger equation analytically. Eigen energies are expressed in terms of the Whittaker function and Coulomb wave function. The results show that impurity binding energy strongly depends on QD size if it is around one effective Bohr radius.
Źródło:
Acta Physica Polonica A; 2011, 120, 2; 234-237
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Si Multidot FETs for Single-Electron Transfer and Single-Photon Detection
Autorzy:
Tabe, M.
Nuryadi, R.
Moraru, D.
Burhanudin, Z.
Yokoi, K.
Ikeda, H.
Powiązania:
https://bibliotekanauki.pl/articles/1813190.pdf
Data publikacji:
2008-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.21.La
73.23.Hk
Opis:
Recently, there have been increasing demands for controlling individual electrons, photons, and dopants in developing nm scale Si devices. Our most recent results on Si single-electron nano-devices will be presented. We have demonstrated single-electron transfer in random-tunnel-junctions by a cycle of ac gate bias, detection of photons and detection of individual acceptor ions by Si single-hole transistor.
Źródło:
Acta Physica Polonica A; 2008, 113, 3; 811-814
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical Rate Equation Approach to Picosecond Charge State Dynamics in CdTe/ZnTe Quantum Dots
Autorzy:
Koperski, M.
Kazimierczuk, T.
Goryca, M.
Wojnar, P.
Golnik, A.
Kossacki, P.
Gaj, J.
Powiązania:
https://bibliotekanauki.pl/articles/1791339.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Et
73.21.La
Opis:
The rate equation is used for description of photoluminescence dynamics after pulsed excitation of various states of quantum dots. The picosecond dynamics of averaged charge state of quantum dot is described. We compare our simulations with the experiment and come up with the conclusion that probability of carrier capture weakly depends on quantum dot charge state and that electrons and holes are captured non-synchronously.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 893-895
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electron and Hole States in Closed Spherical Quantum Dot with Linearly Graded Composition
Autorzy:
Kostić, R.
Stojanović, D.
Powiązania:
https://bibliotekanauki.pl/articles/1808044.pdf
Data publikacji:
2009-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.22.Dj
73.21.La
Opis:
The theoretical investigation of the electron and hole spectra in a quantum dot with a linearly graded composition within the effective mass approximation is presented. The particular example is β-HgS surrounded by CdS. β-HgS core of radius $r_C$ is surrounded by concentric spherical layers each of $Hg_{1-x}Cd_{x}S$ composition (x is function of r) and finally, form radius $r_S$ by CdS. The existence of these intermediate layers, as model of graded composition, influences rapidly electron and hole spectra.
Źródło:
Acta Physica Polonica A; 2009, 115, 4; 768-770
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The City as a Place of Dialogue, Negotiation and Struggle in Terri de la Peña and Mona Ruiz
Autorzy:
Antoszek, Ewa
Powiązania:
https://bibliotekanauki.pl/articles/606283.pdf
Data publikacji:
2006
Wydawca:
Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
Tematy:
Terri de la Pena
Mona Ruiz
Opis:
The multicultural city is a popular setting of many Chicana narratives and short stories. However, in many contemporary works by Chicana authors it loses its typical function of providing a background to the story solely and becomes an active agent that reflects the struggles of its inhabitants. This negotiation is also seen in the interplay between the barrio and the city that is depicted in Chicana literature. This depiction of the city as a place of dialogue, negotiation and struggle against conformity is especially interesting in the two works by two Chicana authors – The Faults by Terri de la Peña and Two Badges: The Lives of Mona Ruiz by Mona Ruiz. Terri de la Peña makes L.A. an arena of fight against sexual conformity, male violence, and against conforming to restricting social norms. Ruiz, on the other hand, concentrates on the relation between the barrio and the city. In her personal story she presents different aspects of non-conformity, which is especially visible in the transformation of her own life, (namely her passage from a gang member to a policewoman in Santa Ana) and her struggle not to conform in both situations. The aspect of dialogue and negotiation is emphasized in both books at the linguistic level, as well, as both authors use code-switching. The purpose of my paper is to compare the two works and analyze the portrait of a contemporary multicultural city that emerges from these books, concentrating on the aspect of the city as a place of (non)conformity in terms of gender, ethnicity, sexuality and class.
Źródło:
Lublin Studies in Modern Languages and Literature; 2006, 29/30; 236-247
0137-4699
Pojawia się w:
Lublin Studies in Modern Languages and Literature
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Weldability of CuZn30 Brass/DP600 Steel Couple by Friction Stir Spot Welding
Autorzy:
Barlas, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1031898.pdf
Data publikacji:
2017-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.20.Vj
87.15.La
Opis:
This study deals with the weldability and assessment of the friction stir spot welding of dissimilar CuZn30 brass/DP600 steel couple. The effects of axial tool load and tool hold time were evaluated in the joining experiments. The tool load forces of 3.2-4.8 kN and the tool hold times of 8 s and 12 s were applied to brass/steel bimetal sheets. Tensile-shear test was employed to investigate the mechanical properties of the joint. Optical and scanning electron microscopies were utilized to characterize the microstructure of the joint having the better mechanical performance, as well as the microhardness test. Temperature measurements were also performed between the lapped sheet faces. The results show that the vertical tool load value has reached more significant influence than the tool hold time. Furthermore, the tensile-shear failure load has increased with increasing tool load and hold time and has reached the highest value of 4.6 kN. The EDS analyses on the fractured surface depict that the copper and zinc concentrations are similar to those of CuZn30 base metal. A peak temperature of 607°C was measured in the weld centre of this joint. No significant microstructural change was observed in the steel sheet, while the fine grains with onion rings were revealed in the brass. Different hardness values were measured depending on microstructural change in the weld zone. Although the onion rings made a contribution to the microhardness, a softened stir zone (129.8 HV), with regard to the brass base metal (149.1 HV), was observed.
Źródło:
Acta Physica Polonica A; 2017, 132, 3; 991-993
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The calculation for strain distributions and electronic structure of InAs/GaAs quantum dots based on the eight-band k·p theory
Autorzy:
Shu, Changgan
Liu, Yumin
Powiązania:
https://bibliotekanauki.pl/articles/1070532.pdf
Data publikacji:
2016-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.21.La
73.63.Kv
Opis:
In order to analyze the strain distribution of InAs/GaAs quantum dot in a pyramidal geometry, the traditional calculation method is based on the single band envelope approximation with the modified band edge from the eight band k·p theory. In this paper, we use the eight band k·p Hamiltonian to calculate, and the piezoelectric effects and the electronic structure are also discussed subsequently. To this end, some necessarily derived formulae in calculations about using the finite element calculation software COMSOL are presented in this paper. The results show the details about strain distributions, piezoelectric effects and electronic structure of an InAs/GaAs pyramidal quantum dot, verify the feasibility and efficiency of the calculation method.
Źródło:
Acta Physica Polonica A; 2016, 129, 3; 371-377
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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