4,690 research outputs found
An urban eco-environmental sensitive areas assessment method based on variable weights combination
When assessing urban eco-environmental sensitive areas (Urban Eco-ESAs) by multi-criteria evaluation method, the widely used weighted linear combination method may inevitably lead to some factors of high sensitive value being neutralized by other factors of low sensitive value, resulting in the neglect of some eco-sensitive areas as a consequence, while on the other hand, Boolean OR combination method, which give a result of high sensitive value as long as any factor has the value of high sensitivity and thus ignore the mutual compensation mechanism among ecological factors, can lead to excessively wide ranges of the eco-sensitive areas. To overcome the defects of these two methods, the authors propose an Urban Eco-ESAs synthesized assessment method giving finely controlled priority to bottleneck factors, and relative model based on selective local encouraging variable weights combination. The method is able to increase the weights of some eco-bottleneck factors on the basis of a weight-changing function in synthesizing multiple factor assessments as long as their assessment values break the bottleneck threshold values, which can guarantee the eco-sensitive areas identified by bottleneck factors being embodied in the final result, while also retain the compensation effect of multiple ecological factors, which makes the results of the assessment more reasonable. In order to deliver this empirical research, Taogang Town in China, which is adjacent to Net lake wetland nature reserve area, has been used as an example to confirm the validity of the method and the model
Giant negative magnetoresistance induced by the chiral anomaly in individual Cd3As2 nanowires
Cd3As2 is a newly booming Dirac semimetal with linear dispersion along all
three momentum directions and can be viewed as 3D analog of graphene. As
breaking of either time reversal symmetry or spatial inversion symmetry, the
Dirac semimetal is believed to transform into Weyl semimetal with exotic chiral
anomaly effect, while the experimental evidence of the chiral anomaly is still
missing in Cd3As2. Here we report the magneto-transport properties of
individual Cd3As2 nanowires. Large negative magnetoresistance (MR) with
magnitude of -63% at 60 K and -11% at 300 K are observed when the magnetic
field is parallel with the electric field direction, giving the evidence of the
chiral magnetic effect in Cd3As2 nanowires. In addition, the critical magnetic
field BC, where there is an extremum of the negative MR, increases with
increasing temperature. As the first observation of chiral anomaly induced
negative MR in Cd3As2 nanowires, it may offer valuable insights for low
dimensional physics in Dirac semimetals.Comment: 4 figure
Tetraaqua{1-[(1H-1,2,3-benzotriazol-1-yl)methyl]-1H-1,2,4-triazole}sulfatocobalt(II) dihydrate
In the title complex, [Co(SO4)(C9H8N6)(H2O)4]·2H2O, the CoII ion is six-coordinated by one N atom from a 1H-1,2,3-benzotriazol-1-yl)methyl]-1H-1,2,4-triazole ligand, one O atom from a monodentate sulfate ligand and four water molecules in a slightly distorted octahedral geometry. The sulfate ligand is rotationally disordered over two sets of sites with refined occupancies of 0.662 (15) and 0.338 (15). In the crystal, complex molecules and solvent water molecules are linked through intermolecular O—H⋯O and O—H⋯N hydrogen bonds into a three-dimensional network
A Descriptive Model of Robot Team and the Dynamic Evolution of Robot Team Cooperation
At present, the research on robot team cooperation is still in qualitative
analysis phase and lacks the description model that can quantitatively describe
the dynamical evolution of team cooperative relationships with constantly
changeable task demand in Multi-robot field. First this paper whole and static
describes organization model HWROM of robot team, then uses Markov course and
Bayesian theorem for reference, dynamical describes the team cooperative
relationships building. Finally from cooperative entity layer, ability layer
and relative layer we research team formation and cooperative mechanism, and
discuss how to optimize relative action sets during the evolution. The dynamic
evolution model of robot team and cooperative relationships between robot teams
proposed and described in this paper can not only generalize the robot team as
a whole, but also depict the dynamic evolving process quantitatively. Users can
also make the prediction of the cooperative relationship and the action of the
robot team encountering new demands based on this model. Journal web page & a
lot of robotic related papers www.ars-journal.co
6-Methoxy-2-[(E)-phenyliminomethyl]phenol
The title compound, C14H13NO2, was obtained by the condensation reaction of o-vanillin and aniline in ethanol. The molecule adopts the phenol–imine tautomeric form and an E conformation with respect to the azomethine C=N bond. The dihedral angle between the aromatic rings is 30.57 (10)°. In the crystal, molecules are linked by intermolecular C—H⋯O hydrogen bonds into zigzag chains parallel to the b axis
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