15,415 research outputs found
Nanoscale Quantification of Octahedral Tilts in Perovskite Films
NiO6-octahedral tilts in ultrathin LaNiO3 films were studied using position
averaged convergent beam electron diffraction (PACBED) in scanning transmission
electron microscopy. Both the type and magnitude of the octahedral tilts were
determined by comparing PACBED experiments to frozen phonon multislice
simulations. It is shown that the out-of-plane octahedral tilt of an epitaxial
film under biaxial tensile stress (0.78 % in-plane tensile strain) increases by
~ 20%, while the in-plane rotation decreases by ~ 80%, compared to the
unstrained bulk material.Comment: The manuscript has been accepted by Applied Physics Letters. After it
is published, it will be found at: http://apl.aip.org
Mean Field Theoretical Structure of He and Be Isotopes
The structures of He and Be even-even isotopes are investigated using an
axially symmetric Hartree-Fock approach with a Skyrme-IIIls mean field
potential. In these simple HF calculations, He and Be isotopes appear to be
prolate in their ground states and Be isotopes have oblate shape isomeric
states. It is also shown that there exists a level crossing when the nuclear
shape changes from the prolate state to the oblate state. The single neutron
levels of Be isotopes exhibit a neutron magic number 6 instead of 8 and show
that the level inversion between 1/2- and 1/2+ levels occurs only for a largely
deformed isotope. Protons are bound stronger in the isotope with more neutrons
while neutron levels are somewhat insensitive to the number of neutrons and
thus the nuclear size and also the neutron skin become larger as the neutron
number increases. In these simple calculations with Skyrme-IIIls interaction no
system with a clear indication of neutron halo was found among He and Be
isotopes. Instead of it we have found 8He+2n, 2n+8He+2n, and 16Be+2n like chain
structures with clusters of two correlated neutrons. It is also shown that 8He
and 14Be in their ground states are below the neutron drip line in which all
nucleons are bound with negative energy and that 16Be in its ground state is
beyond the neutron drip line with two neutrons in positive energy levels.Comment: CM energy correction, 1 figure and more discussions adde
Kinetically-controlled thin-film growth of layered - and NaCoO cobaltate
We report growth characteristics of epitaxial -NaCoO and
-NaCoO thin films on (001) sapphire substrates grown by
pulsed-laser deposition. Reduction of deposition rate could change structure of
NaCoO thin film from -phase with island growth mode to
-phase with layer-by-layer growth mode. The
-NaCoO thin film exhibits spiral surface growth with
multiterraced islands and highly crystallized texture compared to that of the
-NaCoO thin film. This heterogeneous epitaxial film growth
can give opportunity of strain effect of physical properties and growth
dynamics of NaCoO as well as subtle nature of structural change.Comment: accepted for publication in Applied Physics Letter
Infrared Hall conductivity of NaCoO
We report infrared Hall conductivity of
NaCoO thin films determined from Faraday rotation angle
measurements. exhibits two types of hole
conduction, Drude and incoherent carriers. The coherent Drude carrier shows a
large renormalized mass and Fermi liquid-like behavior of Hall scattering rate,
. The spectral weight is suppressed and disappears at T
= 120K. The incoherent carrier response is centered at mid-IR frequency and
shifts to lower energy with increasing T. Infrared Hall constant is positive
and almost independent of temperature in sharp contrast with the dc-Hall
constant.Comment: 5 Pages, 5 Figures. Author list corrected in metadata only, paper is
unchange
Unusual superexchange pathways in a Ni triangular lattice of NiGaS with negative charge-transfer energy
We have studied the electronic structure of the Ni triangular lattice in
NiGaS using photoemission spectroscopy and subsequent model
calculations. The cluster-model analysis of the Ni 2 core-level spectrum
shows that the S 3 to Ni 3 charge-transfer energy is -1 eV and the
ground state is dominated by the configuration ( is a S 3 hole).
Cell perturbation analysis for the NiS triangular lattice indicates that
the strong S 3 hole character of the ground state provides the enhanced
superexchange interaction between the third nearest neighbor sites.Comment: 10 pages, 5 figures, accepted to PR
Species Differentiation Of Fish Samples By Restriction Fragment Length Polymorphism Analysis Of Cytochrome B Gene
Metode pengukuran polimorfisme fragmen hasil pemotongan produkreaksi polimorfik berantai oleh enzim restriksi spesifik (polymerase chainreaction-restriction fragment length polymorphism, RFLP-PCR) telah digunakanuntuk membedakan beberapa jenis ikan mentah. Situs cytochrome b mitokondria,yang diamplifikasi oleh primer universal, dipotong menggunakan empat enzimrestriksi (Bfa I, Hinf I, Msp I, Mbo II) sehingga dapat dianalisa fragment-fragmentpendeknya. Hasil yang diperolah dari pemotongan oleh enzim restriksi tersebutternyata dapat digunakan untuk membedakan tiap jenis ikan sampel. Hasilpenelitian ini menunjukkan bahwa PCR dan RFLP-PCR merupakan metode yangsensitif dan dapat dilakukan dalam waktu singkat untuk membedakan berbagaijenis ikan mentah
Structural origins of the properties of rare earth nickelate superlattices
NiO6 octahedral tilts in the LaNiO3/SrTiO3 superlattices are quantified using
position averaged convergent beam electron diffraction in scanning transmission
electron microscopy. It is shown that maintaining oxygen octahedra connectivity
across the interface controls the octahedral tilts in the LaNiO3 layers, their
lattice parameters and their transport properties. Unlike films and layers that
are connected on one side to the substrate, subsequent LaNiO3 layers in the
superlattice exhibit a relaxation of octahedral tilts towards bulk values. This
relaxation is facilitated by correlated tilts in SrTiO3 layers and is
correlated with the conductivity enhancement of the LaNiO3 layers in the
superlattices relative to individual films.Comment: Accepted for publication in Physical Review B (Rapid Communication
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Understanding of online hotel booking process: A multiple method approach
With the development of information technology, online travel agency has become an important information and communication source in the hospitality industry. The previous studies assessing the online hotel decision-making behaviours, however, mainly focused on behavioural intentions as well as identifying factors that directly influence the transactional behaviours, which rely on a static approach rather than employing the holistic viewpoints. Thus, this research adopted the choice-set model as a theoretical lens to explore online hotel booking behaviours by using multiple methods (i.e. observation and survey methods). The findings of this research shed light on the dynamic patterns of online hotel decision-making process and identify important factors (i.e. internal and external information sources) across sequential stages of the choice-set model. Therefore, this research provides useful implications to online hospitality marketers
3-D self-assembly of flower-like particles via microwave irradiation for water treatment
Three-dimensional (3-D) flower-like shape (FLS) Fe 3O 4 and Fe particles were successfully synthesized using FLS precursor particles that are prepared through a facile microwave-assisted reaction. The mechanism underlying the self-assembly process and shape evolution of FLS particles was systematically investigated by changing reaction parameters such as reaction temperature, reaction time and reaction pressure. During the reaction, iron alkoxide, α-Fe 2O 3 and FeOOH nanoparticles are formed first and are subsequently transformed to 3-D hierarchical FLS particles by the self-assembly of the primary nanoparticles. Reaction temperature and pressure play critical roles in the formation of the hierarchical flower-like superstructure. There is an optimum window of the reaction temperature (∼180 °C) for the formation of 3-D FLS particles, which is attributed to the competition between the self-assembly process and growth process of the nanoparticles. Also, since FeCl 3, ethylene glycol, and urea are used together as raw materials, the appearance of FLS particles is strongly dependent on the reaction pressure. As the reaction pressure becomes larger than 1 MPa, the flake type particles become more thermodynamically favorable than the FLS particles, due to the limited decomposition of urea. Brunauer-Emmett-Teller (BET) analysis shows that FLS particles have a large surface area (>40 m 2 g -1). Because of their high specific surface area and intrinsic reactivity, FLS particles efficiently remove sulfur ions in aqueous solution. This suggests that these flower-like particles can be promising materials to treat toxic gas such as H 2S in an environment-friendly way. © 2012 The Royal Society of Chemistry
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