509 research outputs found
Gender discourse, awareness, and alternative responses for men in everyday living
In this paper, the authors use examples from their experiences to explore the nuances and complexities of contemporary gender practices. They draw on discourse and positioning theories to identify the ways in which culturally dominant, and difficult to notice, gender constructions help shape everyday experiences. In addition, the authors share their view that there are benefits in developing skills in noticing contemporary practices made available by dominant gender constructions. Such noticing expands possibilities for ways of responding and relating that might produce outcomes for men and women that fit with their hopes for living
Fermi-surface topology and the effects of intrinsic disorder in a class of charge-transfer salts containing magnetic ions: β" — (BEDT — TTF)₄ [(H₃O)M(C₂O₄)₃]Υ (M = Ga, Cr, Fr; Υ = C₅H₅N)
We report high-field magnetotransport measurements on β" — (BEDT — TTF)₄ [(H₃O)M(C₂O₄)₃]Υ, where M =Ga, Cr and Fe and Υ = C₅H₅N. We observe similar Shubnikov–de Haas oscillations in all compounds, attributable to four quasi-two-dimensional Fermi-surface pockets, the largest of which corresponds to a cross-sectional area ≈ 8.5% of the Brillouin zone. The cross-sectional areas of the pockets are in agreement with the expectations for a compensated semimetal, and the corresponding effective masses are ∼mₑ, rather small compared to those of other BEDT-TTF salts. Apart from the case of the smallest Fermi-surface pocket, varying the M ion seems to have little effect on the overall Fermi-surface topology or on the effective masses. Despite the fact that all samples show quantum oscillations at low temperatures, indicative of Fermi liquid behavior, the sample and temperature dependence of the interlayer resistivity suggest that these systems are intrinsically inhomogeneous. It is thought that intrinsic tendency to disorder in the anions and/or the ethylene groups of the BEDT-TTF molecules leads to the coexistence of insulating and metallic states at low temperatures. A notional phase diagram is given for the general family of β" — (BEDT — TTF)₄ [(H₃O)M(C₂O₄)₃]Υ salts
Effects of electron correlations and chemical pressures on superconductivity of β''-type organic compounds
We investigate low-temperature electronic states of the series of organic conductors β'' - [bis(ethylenedithio)tetrathiafulvalene] 4[(H3O)M(C2O4)3] G, where M and G represent trivalent metalions and guest organic molecules, respectively. Our structural analyses reveal that the replacement of M and G give rise to systematic change in the cell parameters, especially in the b-axis length, which has a positive correlation with the superconducting transition temperature Tc. Analysis of temperature and magnetic field dependences of the electrical resistance including the Shubnikov–de Haas oscillations elucidates that the variation of charge disproportionation, the effective mass, and the number of itinerant carriers can be systematically explained by the change of the b-axis length. The changes of the transfer integrals induced by stretching/compressing the b axis are confirmed by the band calculation. We discuss that electron correlations in quarter-filled electronic bands lead to charge disproportionation and the possibility of a novel pairing mechanism of superconductivity mediated by charge degrees of freedom
Radical-cation salt with novel BEDT-TTF packing motif containing tris(oxalato)germanate(IV)
The synthesis, crystal structure and resistivity of a new semiconducting BEDT-TTF radical-cation salt containing the tris(oxalato)germanate(IV) anion is reported. BEDT-TTF4[Ge(C2O4)3].0.5dichloromethane crystallizes in the space group P21/c, a = 18.322(7), b = 11.919(4), c = 32.746(11) Å, β = 105.797(5)°, V = 6881(4) Å3, T = 295(1) K, Z = 4. Electrical resistivity measurements show that BEDT-TTF4[Ge(C2O4)3].0.5dichloromethane is a semiconductor with an activation energy of 0.224 eV and room temperature resistivity of 212 Ω cm
Pre-DECIGO can get the smoking gun to decide the astrophysical or cosmological origin of GW150914-like binary black holes
Pre-DECIGO consists of three spacecraft arranged in an equilateral triangle
with 100km arm lengths orbiting 2000km above the surface of the earth. It is
hoped that the launch date will be in the late 2020s.
Pre-DECIGO has one clear target: binary black holes (BBHs) like GW150914 and
GW151226. Pre-DECIGO can detect BBH mergers up to
redshift . The cumulative event rate is in the Pop III origin model of BBHs like GW150914, and it
saturates at , while in the primordial BBH (PBBH) model, the
cumulative event rate is at
even if only of the dark matter consists of PBHs, and it is
still increasing at . In the Pop I/II model of BBHs, the cumulative event
rate is and it saturates at . We present the requirements on orbit accuracy, drag free techniques, laser
power, frequency stability, and interferometer test mass. For BBHs like
GW150914 at 1Gpc, SNR is achieved with the definition of Pre-DECIGO in
the Hz band. Pre-DECIGO can measure the mass spectrum and the
-dependence of the merger rate to distinguish various models of BBHs like
GW150914.
Pre-DECIGO can also predict the direction of BBHs at with an accuracy
of and a merging time accuracy of s at about a
day before the merger so that ground-based GW detectors further developed at
that time as well as electromagnetic follow-up observations can prepare for the
detection of merger in advance. For intermediate mass BBHs at a large redshift
, the QNM frequency after the merger can be within the Pre-DECIGO band
so that the ringing tail can also be detectable to confirm the Einstein theory
of general relativity with SNR.
[abridged]Comment: 17 pages, 10 figures, added some references, modifications to match
the published version in PTE
On the Complexity of Tree Edit Distance with Variables
In this paper, we propose tree edit distance with variables, which is an extension of the tree edit distance to handle trees with variables and has a potential application to measuring the similarity between mathematical formulas. We analyze the computational complexity of several variants of this model. In particular, we show that the problem is NP-complete for ordered trees. We also show for unordered trees that the problem of deciding whether or not the distance is 0 is graph isomorphism complete but can be solved in polynomial time if the maximum outdegree of input trees is bounded by a constant. We also present parameterized and exponential-time algorithms for ordered and unordered cases, respectively
Stereoisomeric semiconducting radical cation salts of chiral bis(2-hydroxypropylthio)ethylenedithioTTF with tetrafluoroborate anions
The new chiral TTF-based donor molecule bis(2-hydroxypropylthio)ethylenedithiotetrathiafulvalene has produced enantiopure R,R and S,S radical cation salts with the tetrafluoroborate anion as well as the nearly isostructural meso/racemate mixture. The enantiopure R,R or S,S salts are both 1:1 semiconducting salts with activation energies of 0.19–0.24 eV, both crystallising in the orthorhombic space group C2221. The semiconducting salt containing both meso and racemic donor cations has a very similar crystal structure but crystallising in the monoclinic space group C2/c (β = 91.39°) with similar S⋯S interactions but a smaller activation energy of 0.15–0.17 eV. This is in contrast to previous families of this type where the disordered racemate has a larger activation energy than its enantiopure salts
Tris(oxamide dioxime-κ2 N,N′)nickel(II) sulfate pentahydrate
The asymmetric unit of the title compound, [Ni(C2H6N4O2)3]SO4·5H2O, contains two complex cations, two sulfate anions and ten lattice water molecules. In both independent cations, the central NiII ion adopts a distorted octahedral coordination involving six imino N atoms of three bidentate oxamide dioxime ligands. The bulk structure is achieved by a three-dimensional network of O—H⋯O and N—H⋯O hydrogen bonds which interlink the ionic partners and some water molecules in such a manner that the lattice framework thus formed defines channels parallel to [100]. The other water molecules are lodged inside these channels. Two of the ten water molecules in the asymmetric unit are disordered over three sites, in 0.356 (3):0.324 (5):0.320 (5) and 0.247 (3):0.293 (6):0.460 (6) occupancy ratios, and one O atom of a sulfate ion is also disordered over two sites, with occupancies of 0.621 (5) and 0.379 (5)
Magnetization Process of One-Dimensional Quantum Antiferromagnet: The Product Wavefunction Renormalization Group Approach
The product-wavefunction renormalization group method, which is a novel
numerical renormalization group scheme proposed recently,is applied to
one-dimensional quantum spin chains in a magnetic field. We draw the
zero-temperature magnetization curve of the spin chains, which excellently
agrees with the exact solution in the whole range of the field.Comment: 14 pages, LaTeX, 5 non-embedded figures, to be published in Physics
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