High yield of graphene by dispersant-free liquid exfoliation of mechanochemically delaminated graphite

Journal of Nanoparticle Research - Orthorhombic titanic acid nanotubes (TAN) have large BET surface area and small-diameter one-dimensional nanotubular morphology, so they can work as a good...     

The Chromatic Spectrum of Mixed Hypergraphs

 A mixed hypergraph is a triple ℋ=(X, ?, ?), where X is the vertex set, and each of ?, ? is a list of subsets of X. A strict k-coloring of ℋ is a surjection c:X→{1,…,k} such that each member of ? has two vertices assigned a common value and each member of ? has two vertices assigned distinct values. The feasible set of H is {k: H has a strict k-coloring}. Among other results, we prove that a finite set of positive integers is the feasible set of some mixed hypergraph if and only if it omits the number 1 or is an interval starting with 1. For the set {s,t} with 2≤s≤t−2, the smallest realization has 2t−s vertices. When every member of ?∪? is a single interval in an underlying linear order on the vertices, the feasible set is also a single interval of integers. Received: May 24, 1999 Final version received: August 31, 2000     

WM groups and Ramsey theory

For amenable groups there are “correspondence principles” relating the behavior under group translation for sets of positive density to that of sets of positive invariant measure for ergodic actions of the group. When the group is also “minimally almost periodic” such actions are automatically weakly mixing; hence the name WM groups. We study here the combinatorial consequences of this state of affairs.     

Normal solvability of linear elliptic problemsRésolubilité normale des problèmes elliptiques linéaires

The paper is devoted to general linear elliptic problems in Hölder spaces. We consider unbounded domains and define limiting problems at infinity. We give a necessary and sufficient condition of normal solvability through uniqueness of solutions of limiting problems. We study a structure of spaces dual to Hölder spaces and specify the subspace of functionals, which provide the condition of normal solvability. This allows us to prove that for Fredholm operators all limiting operators are invertible. To cite this article: V. Volpert, A. Volpert, C. R. Acad. Sci. Paris, Ser. I 334 (2002) 457–462.     

Comparison of the Bayesian and Randomised Decision Tree Ensembles within an Uncertainty Envelope Technique

Multiple Classifier Systems (MCSs) allow evaluation of the uncertainty of classification outcomes that is of crucial importance for safety critical applications. The uncertainty of classification is determined by a trade-off between the amount of data available for training, the classifier diversity and the required performance. The interpretability of MCSs can also give useful information for experts responsible for making reliable classifications. For this reason Decision Trees (DTs) seem to be attractive classification models for experts. The required diversity of MCSs exploiting such classification models can be achieved by using two techniques, the Bayesian model averaging and the randomised DT ensemble. Both techniques have revealed promising results when applied to real-world problems. In this paper we experimentally compare the classification uncertainty of the Bayesian model averaging with a restarting strategy and the randomised DT ensemble on a synthetic dataset and some domain problems commonly used in the machine learning community. To make the Bayesian DT averaging feasible, we use a Markov Chain Monte Carlo technique. The classification uncertainty is evaluated within an Uncertainty Envelope technique dealing with the class posterior distribution and a given confidence probability. Exploring a full posterior distribution, this technique produces realistic estimates which can be easily interpreted in statistical terms. In our experiments we found out that the Bayesian DTs are superior to the randomised DT ensembles within the Uncertainty Envelope technique.     

Optical and luminescent properties of the lead and barium molybdates

Time-resolved luminescence as well as excitation and reflectivity spectra of the oriented lead and barium molybdate single crystals were studied using synchrotron radiation. Features in reflectivity spectra in the fundamental absorption region were analyzed. The contribution of electronic states of lead cation to the formation of the bandgap in PbMoO₄ is supposed. The role of lead states in the intrinsic luminescence of PbMoO₄ is discussed.     

Subspace effective potential theory for configuration interaction

In this article we present an approach which combines the configuration interaction methodology and orbitals derived via single particle equations with a local potential V_eff, the variational parameters of which are determined by minimizing the so‐called subspace functional instead of the traditional single energy functional . In this way ground and excited states orbitals are put on equal footing. The V_eff is restricted to have the form of a model potential expressed in terms of the external potential. One of the advantages of the present direct mapping formulation, is that the effective potential, V_eff, has the symmetry of the external potential. Applications are focused mainly on excited states of the HeH and BeH molecules having spatial and spin symmetries as those of the ground one. © 2016 Wiley Periodicals, Inc.     

Palladium catalyst modified with molybdenum bronze as a possible alternative to platinum in the methanol oxidation reaction

Journal of Solid State Electrochemistry - nPd(H x − 2n MoO3)/GC electrodes were prepared by the surface reaction between red molybdenum bronze (H x MoO3,...     

Enhanced stability of the model mini‐protein in amino acid ionic liquids and their aqueous solutions

Using molecular dynamics simulations, the structure of model mini‐protein was thoroughly characterized in the imidazolium‐based amino acid ionic liquids and their aqueous solutions. Complete substitution of water by organic cations and anions further results in hindered conformational flexibility of the mini‐protein. This observation suggests that amino acid‐based ionic liquids are able to defend proteins from thermally induced denaturation. We show by means of radial distributions that the mini‐protein is efficiently solvated by both solvents due to a good mutual miscibility. Amino acid‐based anions prevail in the first coordination sphere of positively charged sites of the mini‐protein whereas water molecules prevail in the first coordination sphere of negatively charged sites of the mini‐protein. © 2015 Wiley Periodicals, Inc.