A fast wavelet block Jacobi method

In this paper, we develop a fast block Jacobi method for linear systems based on discrete wavelet transform (DWT). Traditional wavelet-based methods for linear systems do not fully utilize the sparsity and the multi-level block structure of the transformed matrix after DWT. For the sake of numerical efficiency, we truncate the transformed matrix to be a sparse matrix by letting the small values be zero. To combine the advantages of the direct method and the iterative method, we solve the sub-systems appropriately based on the multi-level block structure of the transformed matrix after DWT. Numerical examples show that the proposed method is very numerically effective.     

Observation of capillary discharge Ne-like Ar 46.9?nm laser with pre-pulse and main-pulse delay time in the domain of 2–130?μs

We demonstrated the lasing of Ne-like Ar 46.9?nm pumped by capillary discharge with the delay time between pre-pulse and main-pulse ranging from 2 to 130???s. Results show that the laser output reduced significantly when the delay time is much longer than 12???s. The temporal evolution of spontaneous radiation emitted from pre-ionized plasma implies that the observed reduction of the laser output is caused by the axial non-uniformity of pre-ionized plasma density and the decrease of pre-ionized plasma density.     

Synthesis and rheological investigation of self‐healable deferoxamine grafted alginate hydrogel

Deferoxamine grafted alginate (SA‐DFA) was successfully synthesized via amidation of sodium alginate with deferoxamine mesylate as determined by H‐NMR and elemental analysis. SA‐DFA with different graft yield was obtained by adjusting the ratio of sodium alginate and deferoxamine mesylate. It was found that aqueous solution of SA‐DFA could form hydrogel spontaneously due to hydrogen bonding interactions, which also endowed the SA‐DFA hydrogel with self‐healing capability. The healing efficiency of SA‐DFA hydrogels ranged from 53.64 to 90.16%. In addition, surface morphologies of SA‐DFA hydrogels before/after self‐healing process were demonstrated by SEM images. We anticipated that such self‐healable alginate hydrogel would be applied in the field of wound healing. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55, 856–865     

Complex new materials from simple chemistry: Combining an amino‐substituted polysiloxane and carboxylic acids

Changes in rheological, adhesive, and swelling properties of quaternary salts, made by adding one of eight mono‐ or six α,ω‐alkanedioic acids (the latter with two to six or nine carbon atoms) to 6‐7PSil (a polysiloxane with 6%–7% of the monomer units contain a 3‐aminopropyl group) have been correlated with the salt structures. The simple acid‐base chemistry initiates drastic changes in the bulk properties of the materials that depend on the amount and type of the added acid. Thus, the quaternized forms of the 6‐7PSil have significantly enhanced viscoelastic and adhesive properties compared to those of the initial polysiloxane, and they can swell selectively liquids based on their polarity. Also, interpenetrating networks have been made in situ by photopolymerization of salts with vinylic carboxylic acids. DFT calculations on model systems consisting of dimethylammonium α,ω‐alkanedioate salts with two to six carbon atoms provide insights into the interactions responsible for the unexpected dependence of the properties of the 6‐7PSil salts on the chain lengths of the diacids. The potential for applying the methodologies described here to systems with other amino‐substituted polymers and other acid types is noted. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3851–3861     

Global synchronization of weighted cellular neural network with time-varying coupling delays

New sufficient conditions are derived to guarantee the global synchronization of the weighted cellular neural network with multiple time delays. Based on Lyapunov theory, this paper proposes an adaptive feedback controlling method to identify the exact topology of a rather general weighted cellular neural network system with time-varying delays and then considers the synchronization of the neural network with different nodes dynamics. The parameters in this paper are very few and experiments show that the methods presented in this paper are of high application in global synchronization.     

Resonantly pumped continuous wave Er:YAP laser

A continuous wave Er:YAP laser pumped by Mgo:PPLN laser locked at 1535 nm was reported. 170 mW of 1609 nm output was achieved under total incident pump power of 7 W at 77 K. The slope efficiency were 5.0 and 3.1% with the cavity length 75 and 140 mm.     

Size-dependent visible photoluminescence from ZnO nanoparticles prepared via SiO2 network

This study reports a simple method for the synthesis of different size of wurtzite ZnO nanoparticles in assistance of tetraethyl orthosilicate (TEOS). With the increase of the amount of TEOS added, the average size of ZnO nanoparticles was found decreased from ∼14.6 to ∼1.9 nm by characterization of X-ray diffraction (XRD) and high-resolution electron microscopy (HRTEM). The growth of ZnO nanoparticles is proposed to be controlled by the density of the SiO₂ chain mesh which is determined by TEOS amount in precursor. Ultraviolet–visible (UV–VIS) absorption and photoluminescence (PL) spectra show both shift to higher energy in cut-off edge and in visible emission bands respectively. The electron transition process in the mechanism of the visible emission shift was described and related to quantum size effect in ZnO nanoparticles.     

Surface modification by graphene oxide:An efficient strategy to improve the performance of activated carbon based supercapacitors

An efficient and cost-effective strategy to modificate the surface of active carbon (AC), form a 3D-conductive network, and therefore improve the electrochemical performance of AC based supercapacitor was developed.