Indecomposable involutive set-theoretic solutions of the Yang–Baxter equation

We describe the indecomposable involutive non-degenerate set-theoretic solutions of the Yang–Baxter equation as dynamical extensions of non-degenerate left cycle sets. Moreover we characterize the indecomposable dynamical extensions and we produce several examples. As an application we construct a family of finite indecomposable solutions whose structure groups have not the unique product property.     

An Ensemble Kalman Filter Approach Based on Level Set Parameterization for Acoustic Source Identification Using Multiple Frequency Information

In this paper, a reconstruction problem of the spatial dependent acoustic source from multiple frequency data is discussed. Suppose that the source function is supported on a bounded domain and the piecewise constant intensities of the source are known on the support. We characterize unknown domain by the level set technique. And the level set function can be modeled by a Hamilton-Jacobi system. We use the ensemble Kalman filter approach to analyze the system state. This method can avoid to deal with the nonlinearity directly and reduce the computation complexity. In addition, the algorithm can achieve the stable state quickly with the Hamilton-Jacobi system. From some numerical examples, we show these advantages and verify the feasibility and effectiveness.     

A new generation of visible-light-active photocatalysts—The alkaline earth metal bismuthates: Syntheses,compositions, structures,and properties

Semiconductor materials containing bismuth have attracted the attention of researchers over the past several decades, as a result of their high photocatalytic activity in various reactions and/or high efficiency in their photoelectric conversion of solar energy. This interest originated from the observations that bismuth-containing semiconductors have a sufficiently small bandgap, which makes them sensitive to radiation in the visible spectral range; thus, visible-light-active materials. Among the various bismuth-containing semiconductor materials, the bismuthates of alkaline earth metals are distinguished and describe into separate groups. This article reviews research on the known methods of obtaining bismuthates of various alkaline earth metals (magnesium, calcium, strontium, and barium), and further analyzes their composition, structure, and visible-light-active photocatalytic activity.     

A puzzle of the radio-quiet quasar PG 1407+265: Are optical and X-ray emissions produced from a relativistic jet?

PG 1407+265 is a radio quiet quasar that has a relativistic jet.In this report,we show some peculiar properties of its optical and X-ray emissions,which indicate possible non-thermal origins produced from the jet.We use a simple synchrotron + synchrotron self Compton (SSC) model to fit the emissions with different ratios of energy densities between the magnetic field and electrons (η≡U B/U e),which predicts a different γ-ray luminosity.The First LAT AGN Catalog (1LAC) did not include PG 1407+265,which indic...     

Lipschitz properties of the scalarization function and applications

The scalarization functions were used in vector optimization for a long period. Similar functions were introduced and used in economics under the name of shortage function or in mathematical finance under the name of (convex or coherent) measures of risk. The main aim of this article is to study Lipschitz continuity properties of such functions and to give some applications for deriving necessary optimality conditions for vector optimization problems using the Mordukhovich subdifferential.     

On some types of covering rough sets from topological points of view

The concept of coverings is one of the fundamental concepts in topological spaces and plays a big part in the study of topological problems. This motivates the research of covering rough sets from topological points of view. From topological points of view, we can get a good insight into the essence of covering rough sets and make our discussions concise and profound. In this paper, we first construct a type of topology called the topology induced by the covering on a covering approximation space. This notion is indeed in the core of this paper. Then we use it to define the concepts of neighborhoods, closures, connected spaces, and components. Drawing on these concepts, we define several pairs of approximation operators. We not only investigate the relationships among them, but also give clear explanations of the concepts discussed in this paper. For a given covering approximation space, we can use the topology induced by the covering to investigate the topological properties of the space such as separation, connectedness, etc. Finally, a diagram is presented to show that the collection of all the lower and upper approximations considered in this paper constructs a lattice in terms of the inclusion relation ⊆.     

Imidazolium Based Surface Active Ionic Liquids as Novel Micellar Media for Simultaneous and Sensitive Electrochemical Detection of Dopamine and Ascorbic Acid

Surface active ionic liquid (SAIL) micelle assisted, simultaneous and highly sensitive electrochemical sensing of dopamine (DA) and ascorbic acid (AA) is presented. Results presented herein establish that SAILs viz.1‐dodecyl‐3‐methyl imidazolium chloride ([DDMIM][Cl]), 1‐octyl‐3‐methyl imidazolium chloride ([OMIM][Cl]) and 1‐butyl‐3‐methyl imidazolium chloride ([BMIM][Cl]) exhibit a probe and SAIL nature/concentration specific impact on the redox behaviour of hydroquinone (H₂Q), dopamine (DA) and ascorbic acid (AA). To our observations, the electrochemical behaviour of DA and AA is affected oppositely by SAILs with the apparent effects being more appreciable in presence of [DDMIM][Cl]. In the presence of [DDMIM][Cl] micelles, the electro‐oxidation of AA was observed to occur at potentials about 350 mV less positive than required for electrooxidation of DA, an important advantage that minimises the interference of former in sensing of the later. The peak to peak potential separation of 350 mV observed in presence of [DDMIM][Cl] micelles is the largest to be reported so far. The DPV signal for DA and AA displayed a linear response in the concentration range of 6.6 to 99.9 μM and 6.6 to 131.5 μM respectively. Very low detection limits of 0.0161 μM for DA in presence of 39.8 μM AA and 0.0227 μM for AA in presence of 39.8 μM DA were estimated in micellar phase of [DDMIM][Cl].     

Measure and integration: The basic extension and representation theorems in terms of new inner and outer envelopes

The work of the author in measure and integration is based on new inner and outer envelope formations, which replace the traditional Carathéodory outer measure and certain simple suprema and infima. The new formations lead to essential improvements in both the extent and the adequacy of the basic results. However, they did not find an entrance into the recent textbook literature. The present paper seeks to demonstrate their power with the examples of the basic inner and outer extension and representation theorems for set functions and functionals.     

Why indexing works

We develop a simple stock selection model to explain why active equity managers tend to underperform a benchmark index. We motivate our model with the empirical observation that the best performing stocks in a broad market index often perform much better than the other stocks in the index. Randomly selecting a subset of securities from the index may dramatically increase the chance of underperforming the index. The relative likelihood of underperformance by investors choosing active management likely is much more important than the loss those same investors take due to the higher fees of active management relative to passive index investing. Thus, active management may be even more challenging than previously believed, and the stakes for finding the best active managers may be larger than previously assumed.     

Nanoporous silicon flakes as anode active material for lithium-ion batteries

Nanoporous-silicon (np-Si) flakes were prepared using a combination of an electrochemical etching process and an ultra-sonication treatment and the electrochemical properties were studied as an anode active material for rechargeable lithium-ion batteries (LIBs). This fabrication method is a simple, reproducible, and cost effective way to make high-performance Si-based anode active materials in LIBs. The anode based on np-Si flakes exhibited a higher performances (lower capacity fade rate, stability and excellent rate capability at high C-rate) than the anode based on Si nanowires. The excellent performance of the np-Si flake anode was attributed to the hollowness (nanoporous structure) of the anode active material, which allowed it to accommodate a large volume change during cycling.