1,391 research outputs found
Multiferroic FeTeOBr: Alternating spin chains with frustrated interchain interactions
A combination of density functional theory calculations, many-body model
considerations, magnetization and electron spin resonance measurements shows
that the multiferroic FeTeOBr should be described as a system of
alternating antiferromagnetic chains with strong Fe-O-Te-O-Fe bridges
weakly coupled by two-dimensional frustrated interactions, rather than the
previously reported tetramer models. The peculiar temperature dependence of the
incommensurate magnetic vector can be explained in terms of interchain exchange
striction being responsible for the emergent net electric polarization.Comment: 7 pages, 6 figure
Selective hydrogenation of arenes to cyclohexanes in water catalyzed by chitin-supported ruthenium nanoparticles
The selective hydrogenation of arenes to cyclohexanes is promoted by Ru/chitin under aqueous conditions without the loss of CâO/CâN linkages.This work was financially supported by the Ichihara International
Scholarship Foundation (to H. N.), the Institute for
Quantum Chemical Exploration (to H. N.), MEXT (Japan)
through its program âIntegrated Research on Chemical Synthesisâ
(to H. N.) and the Royal Society through its International
Exchange Scheme (to A. E. H. W. and H. N.). K. B. and
B. R. K. thank the UK EPSRC (EP/J500380/1). Y. M. and A. M.
acknowledge the IGER program at NU. We thank Professors
R. Noyori (NU), S. Saito (NU) and K. Shimizu (Hokkaido U)
for their helpful comments.This is the final version of the article. It first appeared from Royal Society of Chemistry at http://dx.doi.org/10.1039/C6CY00899B
New Perspectives in Sinographic Language Processing Through the Use of Character Structure
Chinese characters have a complex and hierarchical graphical structure
carrying both semantic and phonetic information. We use this structure to
enhance the text model and obtain better results in standard NLP operations.
First of all, to tackle the problem of graphical variation we define
allographic classes of characters. Next, the relation of inclusion of a
subcharacter in a characters, provides us with a directed graph of allographic
classes. We provide this graph with two weights: semanticity (semantic relation
between subcharacter and character) and phoneticity (phonetic relation) and
calculate "most semantic subcharacter paths" for each character. Finally,
adding the information contained in these paths to unigrams we claim to
increase the efficiency of text mining methods. We evaluate our method on a
text classification task on two corpora (Chinese and Japanese) of a total of 18
million characters and get an improvement of 3% on an already high baseline of
89.6% precision, obtained by a linear SVM classifier. Other possible
applications and perspectives of the system are discussed.Comment: 17 pages, 5 figures, presented at CICLing 201
Correlated oscillations in Kerr parametric oscillators with tunable effective coupling
We study simultaneous parametric oscillations in a system composed of two
distributed-element-circuit Josephson parametric oscillators in the
single-photon Kerr regime coupled via a static capacitance. The energy of the
system is described by a two-bit Ising Hamiltonian with an effective coupling
whose amplitude and sign depend on the relative phase between parametric pumps.
We demonstrate that the binary phases of the parametric oscillations are
correlated with each other, and that the parity and strength of the correlation
can be controlled by adjusting the pump phase. The observed correlation is
reproduced in our simulation taking pure dephasing into account. The present
result demonstrates the tunability of the Hamiltonian parameters by the phase
of external microwave, which can be used in the the Ising machine hardware
composed of the KPO network.Comment: 9 pages, 8 figure
LHR band emissions at mid-latitude and their relationship to ionospheric ELF hiss and relativistic electrons
LHR band emissions observed at mid-latitude were investigated using data from the EXOS-C (Ohzora) satellite. A typical feature of the LHR band emissions is a continuous banded structure without burst-like and cut-off features whose center frequency decreases as the satellite moves to higher latitudes. A statistical analysis of the occurrence characteristics of the phenomena showed that mid-latitude LHR emissions are distributed inside the plasmapause during magnetically quiet periods, and the poleward boundary of the emission region moves to lower latitudes as the magnetic activity increases. The altitude distribution of the waves suggests that the propagation in the LHR duct formed horizontally in the mid-latitude upper-ionosphere. The emission is closely related to the occurrence of ionospheric ELF hiss. It is also shown that LHR emissions are commonly observed in the slot region of the radiation belt, and they sometimes accompany the enhancement of the ionospheric electron temperature. The generation of the LHR band emissions is discussed based on the observed characteristics
Pi pulsations at substorm onset site
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Vibrotactile pedals : provision of haptic feedback to support economical driving
The use of haptic feedback is currently an underused modality in the driving environment, especially with respect to vehicle manufacturers. This exploratory study evaluates the effects of a vibrotactile (or haptic) accelerator pedal on car driving performance and perceived workload using a driving simulator. A stimulus was triggered when the driver exceeded a 50% throttle threshold, past which is deemed excessive for economical driving. Results showed significant decreases in mean acceleration values, and maximum and excess throttle use when the haptic pedal was active as compared to a baseline condition. As well as the positive changes to driver behaviour, subjective workload decreased when driving with the haptic pedal as compared to when drivers were simply asked to drive economically. The literature suggests that the haptic processing channel offers a largely untapped resource in the driving environment, and could provide information without overloading the other attentional resource pools used in driving
M\"ossbauer, nuclear inelastic scattering and density functional studies on the second metastable state of Na2[Fe(CN)5NO]2H2O
The structure of the light-induced metastable state SII of
Na2[Fe(CN)5NO]2H2O 14 was investigated by transmission M\"ossbauer
spectroscopy (TMS) in the temperature range 15 between 85 and 135 K, nuclear
inelastic scattering (NIS) at 98 K using synchrotron 16 radiation and density
functional theory (DFT) calculations. The DFT and TMS results 17 strongly
support the view that the NO group in SII takes a side-on molecular orientation
18 and, further, is dynamically displaced from one eclipsed, via a staggered,
to a second 19 eclipsed orientation. The population conditions for generating
SII are optimal for 20 measurements by TMS, yet they are modest for
accumulating NIS spectra. Optimization 21 of population conditions for NIS
measurements is discussed and new NIS experiments on 22 SII are proposed
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