5,613 research outputs found
The Magnetic Properties of 1111-type Diluted Magnetic Semiconductor (LaBa)(ZnMn)AsO in the Low Doping Regime
We investigated the magnetic properties of
(LaBa)(ZnMn)AsO with varying from 0.005 to 0.05
at an external magnetic field of 1000 Oe. For doping levels of 0.01,
the system remains paramagnetic down to the lowest measurable temperature of 2
K. Only when the doping level increases to = 0.02 does the ferromagnetic
ordering appear. Our analysis indicates that antiferromagnetic exchange
interactions dominate for 0.01, as shown by the negative Weiss
temperature fitted from the magnetization data. The Weiss temperature becomes
positive, i.e., ferromagnetic coupling starts to dominate, for 0.02.
The Mn-Mn spin interaction parameter is estimated to be in
the order of 10 K for both 0.01 (antiferromagnetic ordered state)
and 0.02 (ferromagnetic ordered state). Our results unequivocally
demonstrate the competition between ferromagnetic and antiferromagnetic
exchange interactions in carrier-mediated ferromagnetic systems.Comment: 9 pages, 3 figure
Leverage Business Analytics and OWA to Recommend Appropriate Projects in Crowdfunding Platform
Nowadays, crowdfunding is becoming more and more popular. Many studies have been published on the crowdfunding platform from different perspectives. However, among all these studies, few are concerned about the recommendation methods, which, in effect, are highly beneficial to crowdfunding websites and the participants. Having considered the situation talked above, this paper works out the several features from the relative projects of user’s current browsing project. Then we give different weights to each feature based on selective attention phenomenon, and adopt the method of OWA operator to calculate the final score of each relative project and accomplish our model by picking out the four projects with different outstanding characteristics. Finally, according to the statistics on China’s famous crowdfunding website, we conducted a group of contrast experiments and eventually testified that our proposed model could, to some extent, help classify and give recommendation effectively. Furthermore, the results of this research can give guidance to the management of crowdfunding websites and they are also very significant advices for the future crowdfunding website development
Critical frontier for the Potts and percolation models on triangular-type and kagome-type lattices II: Numerical analysis
In a recent paper (arXiv:0911.2514), one of us (FYW) considered the Potts
model and bond and site percolation on two general classes of two-dimensional
lattices, the triangular-type and kagome-type lattices, and obtained
closed-form expressions for the critical frontier with applications to various
lattice models. For the triangular-type lattices Wu's result is exact, and for
the kagome-type lattices Wu's expression is under a homogeneity assumption. The
purpose of the present paper is two-fold: First, an essential step in Wu's
analysis is the derivation of lattice-dependent constants for various
lattice models, a process which can be tedious. We present here a derivation of
these constants for subnet networks using a computer algorithm. Secondly, by
means of a finite-size scaling analysis based on numerical transfer matrix
calculations, we deduce critical properties and critical thresholds of various
models and assess the accuracy of the homogeneity assumption. Specifically, we
analyze the -state Potts model and the bond percolation on the 3-12 and
kagome-type subnet lattices , , for which the
exact solution is not known. To calibrate the accuracy of the finite-size
procedure, we apply the same numerical analysis to models for which the exact
critical frontiers are known. The comparison of numerical and exact results
shows that our numerical determination of critical thresholds is accurate to 7
or 8 significant digits. This in turn infers that the homogeneity assumption
determines critical frontiers with an accuracy of 5 decimal places or higher.
Finally, we also obtained the exact percolation thresholds for site percolation
on kagome-type subnet lattices for .Comment: 31 pages,8 figure
Exact critical points of the O() loop model on the martini and the 3-12 lattices
We derive the exact critical line of the O() loop model on the martini
lattice as a function of the loop weight .A finite-size scaling analysis
based on transfer matrix calculations is also performed.The numerical results
coincide with the theoretical predictions with an accuracy up to 9 decimal
places. In the limit , this gives the exact connective constant
of self-avoiding walks on the martini lattice. Using
similar numerical methods, we also study the O() loop model on the 3-12
lattice. We obtain similarly precise agreement with the exact critical points
given by Batchelor [J. Stat. Phys. 92, 1203 (1998)].Comment: 4 pages, 3 figures, 2 table
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