An $$H^1$$-Galerkin mixed finite element method for time fractional reaction–diffusion equation

In this article, an \(H^1\)-Galerkin mixed finite element (MFE) method for solving time fractional reaction–diffusion equation is presented. The optimal time convergence order \(O(\varDelta t^{2-\alpha })\) and the optimal spatial rate of convergence in \(H^1\) and \(L^2\)-norms for variable \(u\) and its gradient \(\sigma \) are derived. Moreover, some numerical results are shown to support our theoretical analysis.     

Predicting Polymorphism of Electrospun Polyvinylidene Fluoride Membranes by Their Morphologies

Although electrospinning of polyvinylidene fluoride (PVDF) has been studied for more than 10 years, the crystalline phase differentiation of the electrospun mats is still normally through the combination of different characterization techniques, and the relationship between polymorphism and morphology of the fibers in electrospun PVDF membranes has never been reported. Here, we show their close relationships by conducting room-temperature electrospinning experiments on various polymer/solvent systems. The electrospun membranes full of bead-free fibers have a very high fraction of β-phase, F(β), over 90%, and high orientation, whereas the membranes comprising beads and/or a large number of beaded fibers most often result in a low fraction of β-phase (F(β) normally below 50%) and low orientation. On the other hand, electrospun membranes consisting of both bead-free fibers and a very limited number of beaded fibers showed a medium high fraction of β-phase, F(β) more than 70% but less than 90%. These findings suggest the feasibility of intuitively predicting the crystalline phase of electrospun PVDF membranes directly by their morphologies, which is obviously simple, inexpensive and convenient for future investigations.     

q-Gronwall不等式及其在分数阶q-微分方程的应用

利用q-微积分的性质,得到时间测度q上的Gronwall不等式;并利用该推广的不等式分别讨论带有Riemann-Liouville和Caputo分数阶导数的q-微分方程的解对分数阶导数的阶数和初值的依赖性.     

Interpolation of Morrey-Campanato and related smoothness spaces

We study the interpolation of Morrey-Campanato spaces and some smoothness spaces based on Morrey spaces, e. g., Besov-type and Triebel-Lizorkin-type spaces. Various interpolation methods, including the complex method, the ±-method and the Peetre-Gagliardo method, are studied in such a framework. Special emphasis is given to the quasi-Banach case and to the interpolation property.     

Blind separation of fluorescence spectra using sparse non‐negative matrix factorization on right hand factor

Sparse non‐negative matrix factorization on right side factor (SNMF/R) has better performance in feature extraction than non‐negative matrix factorization. In this work, SNMF/R was first used to separate the overlapped three‐dimensional fluorescence spectra of polycyclic aromatic hydrocarbons mixtures in pure water, lake water, and river water, respectively. It is found that the similarity coefficients between the acquired three‐dimensional spectra and the corresponding reference spectra with random initials are all above 0.80; the recognition rate of SNMF/R is higher than that of PARAFAC and non‐negative matrix factorization algorithms, especially in the case of lake water and river water samples. In addition, SNMF/R does not need any initialization scheme designing during spectra separation. These results demonstrate that SNMF/R is an appropriate algorithm to separate the overlapped fluorescence spectra of polycyclic aromatic hydrocarbons in aquatic environment accurately and effectively. Copyright © 2015 John Wiley & Sons, Ltd.     

Synthesis and Herbicidal Activities of Sodium Hydrogen 1-(Substituted Phenoxyacetoxy)Alkylphosphonates

Abstract

A series of sodium hydrogen 1-(substituted phenoxyacetoxy) alkylphosphonates was designed and synthesized. The test for herbicidal activity indicated that most of the phosphonates (8) possessed excellent postemergence herbicidal activities against broadleaf weeds. Especially, 8f and 8g showed the best herbicidal activity against rape and amaranth with more than 95% inhibitory rate.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Synthesis and Herbicidal Activity of [(Substituted Phenoxyacetoxy) (Substituted Phenyl)Methyl](Methyl) Phosphinates Containing Fluorine

Abstract

A series of [(substituted phenoxyacetoxy)(substituted phenyl)methyl](methyl)phos- phinates containing fluorine were designed and synthesized. All the synthesized compounds were identified by elemental analysis, IR, ¹H NMR, mass spectrometry. O-methyl [(2-fluorophenoxyacetoxy)(2,4-dichlorophenyl)methyl](methyl)phosphinate was further analyzed by X-ray single-crystal diffraction. Their herbicidal activity against a set of weed species was examined. Some of the compounds showed potential herbicidal activity, which provided some indications for further studies on structure modification.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Synthesis and Herbicidal Activities of 2-Methylpropan-2-Aminium Methyl 1-(Substituted Phenoxyacetoxy) Alkylphosphonates

Abstract

A series of 2-methylpropan-2-aminium methyl 1-(substituted phenoxyacetoxy) alkylphosphonates were selectively synthesized by reacting the corresponding dimethyl 1-(substitutedphenoxyacetoxy)alkylphosphonates with an excess of 2-methylpropan-2-amine. All the title compounds were identified by IR, ¹H NMR, and ³¹P NMR, some of them were further analyzed by ¹⁹F NMR and ¹³C NMR. Their herbicidal activity was investigated and the results showed that most of the demethylated aminium salts exhibited notable herbicidal activities against Brassica napus L. and Echinochloa crusgalli.

Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfer, and Silicon and the Related Elements for the following free supplemental files: Additional text, figures and tables.