Mutual relation of leakage and emission currents in the Al-Al2O3-Al system

In the present paper the analysis of VA characteristics of the leakage current determined experimentally for the Al-Al₂O₃-Al system is discussed. It is shown that the total leakage current is given by a sum of several local currents from the single places of the dielectric given by various mechanisms acting simultaneously. The tunnel component of the leakage current passes through a part of the dielectric area only. This current component obeys the same regularities holding for the case of emission current of electrons into vacuum. Comparison of the values of applied field intensity obtained for this tunnel component leakage current with the values corresponding to the Fowler-Nordheim equation suggests the assumption of a nonuniform potential distribution in the dielectric, i.e. the existence of a region where the potential drop agrees with the theoretical values and the region of a lower potential drop. Further, the influence of the position of potential barrier and the transmission probability over the top electrode on the emission VA characteristics is shown.     

Calculation of average multiplicity in a simple scheme incorporating the Harari Pomeron-intercept hypothesis

Average multiplicities are calculated within a simple finite-energy sum rule sheme assuming (i) the conventional multiperipheral and (ii) the Harari hypothesis about the dependence of the Pomeron intercept on the strength of strong interactions. Case (ii) agrees better with experiment.     

Saturating Sperner Families

A family ${\mathcal{F} \subseteq 2^{[n]}}$ saturates the monotone decreasing property ${\mathcal{P}}$ if ${\mathcal{F}}$ satisfies ${\mathcal{P}}$ and one cannot add any set to ${\mathcal{F}}$ such that property ${\mathcal{P}}$ is still satisfied by the resulting family. We address the problem of finding the minimum size of a family saturating the k-Sperner property and the minimum size of a family that saturates the Sperner property and that consists only of l-sets and (l + 1)-sets.     

Towards a de Bruijn–Erdős Theorem in the L_1-Metric

A well-known theorem of de Bruijn and Erd?s states that any set of $n$ non-collinear points in the plane determines at least $n$ lines. Chen and Chvátal asked whether an analogous statement holds within the framework of finite metric spaces, with lines defined using the notion of betweenness. In this paper, we prove that the answer is affirmative for sets of $n$ points in the plane with the $L_1$ metric, provided that no two points share their $x$ - or $y$ -coordinate. In this case, either there is a line that contains all $n$ points, or $X$ induces at least $n$ distinct lines. If points of $X$ are allowed to share their coordinates, then either there is a line that contains all $n$ points, or $X$ induces at least $n/37$ distinct lines.     

Synthesis of a series of ethylene glycol modified water-soluble tetrameric TPE-amphiphiles with pyridinium polar heads: Towards applications as light-up bioprobes in protein and DNA assay,and wash-free imaging of bacteria

Available online Development of water soluble AIE-active “light-up” bioprobes for the detection of biomacromolecules has drawn huge research interests in recent past. In this study, a series of ethylene glycol modified water soluble tetrameric tetraphenylethylene amphiphiles with pyridinium polar heads (TPE-xEG-Py, x = 3, 4, 6 or 1a-c) have been synthesized by varying the ethylene glycol spacer. Their unique structure allows them to form vesicles and other nanoaggregates in aqueous solutions. These amphiphiles were successfully utilized for fluorimetric detection and quantitation of BSA and DNA based on the electrostatic interactions to trigger AIE-emission from the TPE moiety. The electrostatic interaction was also proved very effective in wash-free imaging of both Gram-negative (E. coli) and Gram-positive (S. aureus) bacteria with up to 92 folds increase in fluorescence response within bacterial concentration 0–12 × 10⁸ CFU mL^?1. The strategy is advantageous due to cost-effective and easy synthesis, high water solubility, and fast response.     

First reported propylphosphonic anhydride (T3P®) mediated Robinson–Gabriel cyclization. Synthesis of natural and unnatural 5-(3-indolyl)oxazoles

In the present work, a propylphosphonic anhydride (T3P^®) assisted Robinson–Gabriel cyclization of N-acyl-β-oxotryptamines for the synthesis of 2-substituted-5-(3-indolyl)oxazoles has been developed. The reactions proceeded smoothly in acetonitrile under microwave irradiation, and the product isolation required only an extraction and subsequent crystallization; no chromatography was necessary. The desired products were obtained in good to excellent yields.     

Triangle Percolation in Mean Field Random Graphs—with PDE

We apply a PDE-based method to deduce the critical time and the size of the giant component of the “triangle percolation” on the Erdős-Rényi random graph process investigated by Derényi, Palla and Vicsek in (Phys. Rev. Lett. 94:160202, [2005]; J. Stat. Phys. 128:219–227, [2007]).     

Who's talking first? Consensus or lack thereof in coevolving opinion formation models

We investigate different opinion formation models on adaptive network topologies. Depending on the dynamical process, rewiring can either (i) lead to the elimination of interactions between agents in different states, and accelerate the convergence to a consensus state or break the network in noninteracting groups or (ii), counterintuitively, favor the existence of diverse interacting groups for exponentially long times. The mean-field analysis allows us to elucidate the mechanisms at play. Strikingly, allowing the interacting agents to bear more than one opinion at the same time drastically changes the model's behavior and leads to fast consensus.     

Removal of Water-Soluble Extractives Improves the Enzymatic Digestibility of Steam-Pretreated Softwood Barks

Softwood bark contains a large amounts of extractives—i.e., soluble lipophilic (such as resin acids) and hydrophilic components (phenolic compounds, stilbenes). The effects of the partial removal of water-soluble extractives before acid-catalyzed steam pretreatment on enzymatic digestibility were assessed for two softwood barks—Norway spruce and Scots pine. A simple hot water extraction step removed more than half of the water-soluble extractives from the barks, which improved the enzymatic digestibility of both steam-pretreated materials. This effect was more pronounced for the spruce than the pine bark, as evidenced by the 30 and 11% glucose yield improvement, respectively, in the enzymatic digestibility. Furthermore, analysis of the chemical composition showed that the acid-insoluble lignin content of the pretreated materials decreased when water-soluble extractives were removed prior to steam pretreatment. This can be explained by a decreased formation of water-insoluble “pseudo-lignin” from water-soluble bark phenolics during the acid-catalyzed pretreatment, which otherwise results in distorted lignin analysis and may also contribute to the impaired enzymatic digestibility of the barks. Thus, this study advocates the removal of extractives as the first step in the processing of bark or bark-rich materials in a sugar platform biorefinery.