6,372 research outputs found
Effect of an InP/InGaAs Interface on Spin-orbit Interaction in InAlAs/InGaAs Heterostructures
We report the effect of the insertion of an InP/InGaAs
Interface on Rashba spin-orbit interaction in
InAlAs/InGaAs quantum wells. A small spin
split-off energy in InP produces a very intriguing band lineup in the valence
bands in this system. With or without this InP layer above the
InGaAs well, the overall values of the spin-orbit coupling
constant turned out to be enhanced or diminished for samples with the
front- or back-doping position, respectively. These experimental results, using
weak antilocalization analysis, are compared with the results of the
theory. The actual conditions of the interfaces and
materials should account for the quantitative difference in magnitude between
the measurements and calculations.Comment: Submitted for publication; v2 to adjust Eq.6; v3 to correct the
figure file name; v4, a revised version accepted for publication in Phys.
Rev.
Use of Combined Hartree-Fock-Roothaan Theory in Evaluation of Lowest States of K [Ar]4s^0 3d^1 and Cr+ [Ar]4s^0 3d^5 Isoelectronic Series Over Noninteger n-Slater Type Orbitals
By the use of integer and noninteger n-Slater Type Orbitals in combined
Hartree-Fock-Roothaan method, self consistent field calculations of orbital and
lowest states energies have been performed for the isoelectronic series of open
shell systems K [Ar]4s^0 3d^1 2(D) (Z=19-30) and Cr+ [Ar] 4s^0 3d^5 6(S)
(Z=24-30). The results of calculations for the orbital and total energies
obtained from the use of minimal basis sets of integer- and noninteger n-Slater
Type Orbitals are given in tables. The results are compared with the
extended-basis Hartree-Fock computations. The orbital and total energies are in
good agreement with those presented in the literature. The results are
accurately and considerably can be useful in the application of
non-relativistic and relativistic combined Hartree-Fock-Roothaan approach for
heavy atomic systems.Comment: 11 pages, 6 tables, 2 figures. submitte
Competition between Spin-Orbit Interaction and Zeeman Coupling in Rashba 2DEGs
We investigate systematically how the interplay between Rashba spin-orbit
interaction and Zeeman coupling affects the electron transport and the spin
dynamics in InGaAs-based 2D electron gases. From the quantitative analysis of
the magnetoconductance, measured in the presence of an in-plane magnetic field,
we conclude that this interplay results in a spin-induced breaking of time
reversal symmetry and in an enhancement of the spin relaxation time. Both
effects, due to a partial alignment of the electron spin along the applied
magnetic field, are found to be in excellent agreement with recent theoretical
predictions.Comment: 4 figures and 4 page
Kinetic processes of mantle minerals
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution September 1999This dissertation discusses the experimental results designed to constrain the processes of
MORB generation. The main focus of this study is to investigate the location and the
related processes of the transformation boundary from spinel to garnet peridotite facies at
subsolidus conditions, because the presence of garnet in melting residues has significant
influence to the conclusion drawn from geochemical/geophysical observations. Using an
approach that monitors the rate of reaction progresses, the experimental results confirmed
the presence of a region that garnet and spinel coexist in peridotite compositions. The
trace element distribution among the product phases (opx and cpx) subsequent to the
garnet breakdown reaction is in disequilibrium, due to the differences of diffusivity
between major and trace elements. The presence of disequilibrium distribution in nature
may be used to infer time scales of geodynamic processes. Diffusion coefficients of A1 in
diopside are experimentally determined, and used for modeling the equilibration of major
elements in pyroxene during MORB genesis. In summary, this dissertation contributes
two major inferences: the location of the transformation boundaries of the gamet-spinel
peridotite; the presence of disequilibrium trace elements distribution with equilibrium
major elements distribution in mantle pyroxenes
Enhancements to Sperry/NASTRAN
Reviewed is the enhancement to NASTRAN program performed by NUK (Nippon Univac Kaisha, Ltd.) added to Level 15.5. Features discussed include intermediate checkpoint-restart in triangular decomposition, I/O improvement, multibanked memory and new plate element. The first three improvements provide the capability to solve significantly large size problems, while the new elements release the analyst from the cumbersome work to constrain the singularities caused by the lack of stiffness of inplane rotation of old plate elements
Spin, charge and orbital fluctuations in a multi-orbital Mott insulator
The two-orbital degenerate Hubbard model with distinct hopping integrals is
studied by combining dynamical mean-field theory with quantum Monte Carlo
simulations. The role of orbital fluctuations for the nature of the Mott
transition is elucidated by examining the temperature dependence of spin,
charge and orbital susceptibilities as well as the one-particle spectral
function. We also consider the effect of the hybridization between the two
orbitals, which is important particularly close to the Mott transition points.
The introduction of the hybridization induces orbital fluctuations, resulting
in the formation of a Kondo-like heavy-fermion behavior, similarly to
electron systems, but involving electrons in bands of comparable width.Comment: 8 pages, 9 figure
Measurement by FIB on the ISS: Two Emissions of Solar Neutrons Detected?
A new type of solar neutron detector (FIB) was launched onboard the Space
Shuttle Endeavour on July 16, 2009, and it began collecting data at the
International Space Station (ISS) on August 25, 2009. This paper summarizes the
three years of observations obtained by the solar neutron detector FIB until
the end of July 2012. The solar neutron detector FIB can determine both the
energy and arrival direction of neutrons. We measured the energy spectra of
background neutrons over the SAA region and elsewhere, and found the typical
trigger rates to be 20 counts/sec and 0.22 counts/sec, respectively. It is
possible to identify solar neutrons to within a level of 0.028 counts/sec,
provided that directional information is applied. Solar neutrons were observed
in association with the M-class solar flares that occurred on March 7 (M3.7)
and June 7 (M2.5) of 2011. This marked the first time that neutrons were
observed in M-class solar flares. A possible interpretaion of the prodcution
process is provided.Comment: 36 pages, 16 figures, and 3 Tables; Advanced in Astronmy, 2012,
Special issue on Cosmic Ray Variablity:Century of Its Obseravtion
Venäjänkielisten lasten äidinkielen tukeminen varhaiskasvatuksessa
Toiminnallinen opinnäytetyön tarkoitus on tukea venäläisten lasten äidinkielen kehittymistä. Tekijän oma äidinkieli on myös venäjä. Toiminnallisen osan menetelmänä käytin kerhoa nimellä Sadun parissa, jonka pohjana oli lasten kirjallisuus. Tuokiot toteutuivat lapsiryhmässä, jossa oli viisi kuusivuotiaita lasta. Kerhon tavoitteena oli rohkaista lapsia puhumaan äidinkieltä ja saada lapsia kiinnostumaan lasten kirjallisuudesta.
Opinnäytetyön tietoperusta muodostaa viitekehityksen toteutukselle. Se auttaa lukijaa ymmärtämään äidinkielen merkitys maahanmuuttajille ja lasten äidinkielen tukemisen tärkeyttä. Teoriatausta käsittelee kielen keskeinen merkitystä ja sen yhteyttä kulttuuriin, maahanmuuttajataustaisten lasten kielikasvatusta varhaiskasvatuksessa ja kasvattajan roolia äidinkielen tukemisessa.
Opinnäytetyöni onnistui hyvin. Lapset osallistuivat toimintaan innokkaasti. Sain hyviä palautteita vanhemmilta ja lastentarhanopettajalta, joita kertoivat lasten ja vanhempien tyytyväisyydestä kerhon toiminnastaЦелью дипломной работы является поддержка развития родного языка русскоязычных детей. Родной язык автора тоже русский. Практической частью работы является кружок В гостях у сказки, за основу которого взята детская литература. Занятия проводились с группой детей, в которой пять шестилеток. Целью кружка было поощрение общения на родном языке, а также пробуждение у детей интереса к детской литературе.
Теоретическая часть работы представляет собой основу для выполнения практической части. Теория помогает читателю понять значение родного языка для иммигрантов и значимость поддержки родного языка ребенка. Tеоретическая часть содержит следующие понятия: общее значение языка и его связь с культурой, дошкольное языковое воспитание детей иммигрантов и роль воспитателя в поддержке родного языка.
Практическая часть работы удалась хорошо. Дети принимали участие в деятельности кружка с воодушевлением. Я получила хорошие отзывы от родителей и воспитателя детского сада, которые говорят об удовлетворенности детей и их родителей деятельностью кружк
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