3,422 research outputs found
Superconducting state in the non-centrosymmetric Mg_{9.3}Ir_{19}B_{16.7} and Mg_{10.5}Ir_{19}B_{17.1} revealed by NMR
We report ^{11}B NMR measurements in non-centrosymmetric superconductors
Mg_{9.3}Ir_{19}B_{16.7} (T_c=5.8 K) and Mg_{10.5}Ir_{19}B_{17.1} (T_c=4.8 K).
The spin lattice relaxation rate and the Knight shift indicate that the Cooper
pairs are predominantly in the spin-singlet state with an isotropic gap.
However, Mg_{10.5}Ir_{19}B_{17.1} is found to have more defects and the spin
susceptibility remains finite even in the zero-temperature limit. We interpret
this result as that the defects enhance the spin-orbit coupling and bring about
more spin-triplet component.Comment: for a proper, high-resolution Fig.5, contact the corresponding autho
Theory for high spin systems with orbital degeneracy
High-spin systems with orbital degeneracy are studied in the large spin
limit. In the absence of Hund's coupling, the classical spin model is mapped
onto disconnected orbital systems with spins up and down, respectively. The
ground state of the isotropic model is an orbital valence bond state where each
bond is an orbital singlet with parallel spins, and neighbouring bonds interact
antiferromagnetically. The possible relevance to the transition metal oxides
are discussed.Comment: 4 page, three figures, to appear in Phys. Rev. Let
DehazeNet: An end-to-end system for single image haze removal
© 1992-2012 IEEE. Single image haze removal is a challenging ill-posed problem. Existing methods use various constraints/priors to get plausible dehazing solutions. The key to achieve haze removal is to estimate a medium transmission map for an input hazy image. In this paper, we propose a trainable end-to-end system called DehazeNet, for medium transmission estimation. DehazeNet takes a hazy image as input, and outputs its medium transmission map that is subsequently used to recover a haze-free image via atmospheric scattering model. DehazeNet adopts convolutional neural network-based deep architecture, whose layers are specially designed to embody the established assumptions/priors in image dehazing. Specifically, the layers of Maxout units are used for feature extraction, which can generate almost all haze-relevant features. We also propose a novel nonlinear activation function in DehazeNet, called bilateral rectified linear unit, which is able to improve the quality of recovered haze-free image. We establish connections between the components of the proposed DehazeNet and those used in existing methods. Experiments on benchmark images show that DehazeNet achieves superior performance over existing methods, yet keeps efficient and easy to use
Organoaluminium complexes of ortho-, meta-, para-anisidines: synthesis, structural studies and ROP of ε-caprolactone (and rac-lactide)
Reaction of Me₃Al (two equivalents) with ortho-, meta- or para-anisidine, (OMe)(NH₂)C₆H₄, affords the complexes {[1,2-(OMe),NC₆H₄(μ-Me₂Al)](μ-Me₂Al)}₂ (1), [1,3-(Me₃AlOMe),NHC₆H₄(μ-Me₂Al)]2 (2) or [1,4-(Me₃AlOMe),NHC₆H₄(μ-Me₂Al)]₂ (3), respectively. The molecular structures of 1–3 have been determined and all three complexes were found to be highly active for the ring opening polymerization (ROP) of ε-caprolactone. 1 was found highly active either with or without benzyl alcohol present; at various temperatures, the activity order 1 > 2 ≈ 3 was observed. For the ROP of rac-lactide results for 1–3 were poor
Pressure-induced unconventional superconductivity near a quantum critical point in CaFe2As2
75As-zero-field nuclear magnetic resonance (NMR) and nuclear quadrupole
resonance (NQR) measurements are performed on CaFe2As2 under pressure. At P =
4.7 and 10.8 kbar, the temperature dependences of nuclear-spin-lattice
relaxation rate (1/T1) measured in the tetragonal phase show no coherence peak
just below Tc(P) and decrease with decreasing temperature. The
superconductivity is gapless at P = 4.7 kbar but evolves to that with multiple
gaps at P = 10.8 kbar. We find that the superconductivity appears near a
quantum critical point under pressures in the range 4.7 kbar < P < 10.8 kbar.
Both electron correlation and superconductivity disappear in the collapsed
tetragonal phase. A systematic study under pressure indicates that electron
correlations play a vital role in forming Cooper pairs in this compound.Comment: 5pages, 5figure
Physical accessible transformations on a finite number of quantum states
We consider to treat the usual probabilistic cloning, state separation,
unambiguous state discrimination, \emph{etc} in a uniform framework. All these
transformations can be regarded as special examples of generalized completely
positive trace non-increasing maps on a finite number of input states. From the
system-ancilla model we construct the corresponding unitary implementation of
pure pure, pure mixed, mixed pure, and mixed mixed
states transformations in the whole system and obtain the necessary and
sufficient conditions on the existence of the desired maps. We expect our work
will be helpful to explore what we can do on a finite set of input states.Comment: 7 page
Low-carbon development via greening global value chains: a case study of Belarus
The rise of global value chains (GCVs) has seen the transfer of carbon emissions embodied in every step of international trade. Building a coordinated, inclusive and green GCV can be an effective and efficient way to achieve carbon emissions mitigation targets for countries that participate highly in GCVs. In this paper, we first describe the energy consumption as well as the territorial and consumption-based carbon emissions of Belarus and its regions from 2010 to 2017. The results show that Belarus has a relatively clean energy structure with 75% of Belarus' energy consumption coming from imported natural gas. The ‘chemical, rubber and plastic products' sector has expanded significantly over the past few years; its territorial-based emissions increased 10-fold from 2011 to 2014, with the ‘food processing' sector displaying the largest increase in consumption-based emissions. An analysis of regional emissions accounts shows that there is significant regional heterogeneity in Belarus with Mogilev, Gomel and Vitebsk having more energy-intensive manufacturing industries. We then analysed the changes in Belarus' international trade as well as its emission impacts. The results show that Belarus has changed from a net carbon exporter in 2011 to a net carbon importer in 2014. Countries along the Belt and Road Initiative, such as Russia, China, Ukraine, Poland and Kazakhstan, are the main trading partners and carbon emission importers/exporters for Belarus. ‘Construction’ and ‘chemical, rubber and plastic products' are two major emission-importing sectors in Belarus, while ‘electricity' and ‘ferrous metals' are the primary emission-exporting sectors. Possible low-carbon development pathways are discussed for Belarus through the perspectives of global supply and the value chain
Spin-Rotation Symmetry Breaking in the Superconducting State of CuxBi2Se3
Spontaneous symmetry breaking is an important concept for understanding
physics ranging from the elementary particles to states of matter. For example,
the superconducting state breaks global gauge symmetry, and unconventional
superconductors can break additional symmetries. In particular, spin rotational
symmetry is expected to be broken in spin-triplet superconductors. However,
experimental evidence for such symmetry breaking has not been conclusively
obtained so far in any candidate compounds. Here, by 77Se nuclear magnetic
resonance measurements, we show that spin rotation symmetry is spontaneously
broken in the hexagonal plane of the electron-doped topological insulator
Cu0.3Bi2Se3 below the superconducting transition temperature Tc=3.4 K. Our
results not only establish spin-triplet superconductivity in this compound, but
may also serve to lay a foundation for the research of topological
superconductivity
Static flow on complete noncompact manifolds I: short-time existence and asymptotic expansions at conformal infinity
In this paper, we study short-time existence of static flow on complete
noncompact asymptotically static manifolds from the point of view that the
stationary points of the evolution equations can be interpreted as static
solutions of the Einstein vacuum equations with negative cosmological constant.
For a static vacuum we also compute the asymptotic expansions of
and at conformal infinity.Comment: 25 page
Exact Analysis of Scaling and Dominant Attractors Beyond the Exponential Potential
By considering the potential parameter as a function of another
potential parameter [47], We successfully extend the analysis of
two-dimensional autonomous dynamical system of quintessence scalar field model
to the analysis of three-dimension, which makes us be able to research the
critical points of a large number of potentials beyond the exponential
potential exactly. We find that there are ten critical points in all, three
points } are general points which are possessed by all
quintessence models regardless of the form of potentials and the rest points
are closely connected to the concrete potentials. It is quite surprising that,
apart from the exponential potential, there are a large number of potentials
which can give the scaling solution when the function
equals zero for one or some values of
and if the parameter also satisfies the condition
Eq.(16) or Eq.(17) at the same time. We give the differential equations to
derive these potentials from . We also find that, if some
conditions are satisfied, the de-Sitter-like dominant point and the
scaling solution point (or ) can be stable simultaneously but
and can not be stable simultaneity. Although we survey scaling
solutions beyond the exponential potential for ordinary quintessence models in
standard general relativity, this method can be applied to other extensively
scaling solution models studied in literature[46] including coupled
quintessence, (coupled-)phantom scalar field, k-essence and even beyond the
general relativity case . we also discuss the disadvantage
of our approach.Comment: 16 pages,no figure, this new revision has taken the suggestions from
CQG referees and has been accepted for publication in Classical and Quantum
Gravit
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