Competing orders and inter-layer tunnelling in cuprate superconductors: A finite temperature Landau theory

We propose a finite temperature Landau theory that describes competing orders and interlayer tunneling in cuprate superconductors as an important extension to a corresponding theory at zero temperature [Nature {\bf 428}, 53 (2004)], where the superconducting transition temperature $T_c$ is defined in three possible ways as a function of the zero temperature order parameter. For given parameters, our theory determines $T_c$ without any ambiguity. In mono- and double-layer systems we discuss the relation between zero temperature order parameter and the associated transition temperature in the presence of competing orders, and draw a connection to the puzzling experimental fact that the pseudo-gap temperature is much higher than the corresponding energy scale near optimum doping. Applying the theory to multi-layer systems, we calculate the layer-number dependence of $T_c$. In a reasonable parameter space the result turns out to be in agreement with experiments.Comment: 5 pages, 3 figure

A Model-Driven Method for Quality Reviews Detection: An Ensemble Model of Feature Selection

With the rapid growth of e-commerce and user-generated content online, the increasing product online reviews have significant influence on both buyers and sellers. However, among the thousands of online reviews, only the reviews of high-quality matters to the market, thus quality reviews detection rises in response to the requirement of retrieving authentic feedbacks from consumers. In this paper, a state-of-the-art ensemble model, gradient boosting decision trees (GBDT), is applied to select useful features for quality evaluation of online reviews. Firstly, four types of features are extracted based on information adoption theory. Then, the GBDT model is adopted to select useful features for quality reviews detection. At last, comparative experiments are conducted through online reviews of searching goods, based on two baseline models such as Decision Tree and Logistic Regression, and the results show that GBDT model achieves a better performance in detecting reviews of high-quality. This research indicates that product attributes, reviewer characteristics and objectiveness of reviews are key ingredients in high quality reviews

3,6-Dihydr­oxy-2′-[(2-hydr­oxy-1-naphth­yl)methyl­eneamino]xanthene-9-spiro-1′-isoindolin-3′-one acetonitrile solvate

The title compound, C31H20N2O5·C2H3N, was synthesized by the reaction of fluorescein hydrazide and excess 2-hydr­oxy-1-naphthaldehyde in acetonitrile. The spirolactam ring is planar and is nearly at right angles to the two benzene rings of the xanthene system. The dihedral angle between the two benzene rings of the xanthene system is 9.92 (4)°. In the crystal structure, the mol­ecules are linked into extended two-dimensional networks by inter­molecular hydrogen bonding. Acetonitrile mol­ecules are located in the voids between the two-dimensional networks