Facile and efficient synthesis of fluorinated fullerene-fused 1,3-dioxolanes: reaction of C60 with fluorinated aromatic aldehyde mediated by lithium perchlorate

A series of fluorinated fullerene-fused 1,3-dioxolanes have been facilely and efficiently synthesized in the presence of easily available LiClO₄·3H₂O. The influences of the number of fluoro-substituents and their positions linked to the phenyl ring on the isolated yield of fullerene-fused 1,3-dioxolanes have been studied in detail. Based on reaction facts, a possible reaction mechanism for the formation of fluorinated fullerene-fused 1,3-dioxolanes has been proposed. Furthermore, detailed ultraviolet absorption spectra, fluorescence emission spectra, and cyclic voltammogram further explain the optical properties and electronic transmission capabilities of the products.     

Chiral sensing of Eu(III)‐containing achiral polymer complex from chiral amino acids coordination induction

The β‐diketonate‐based achiral polymer P‐1 could be synthesized by the polymerization of 3,7‐dibromo‐2,8‐dimethoxy‐5,5‐dioctyl‐5H‐dibenzo[b,d]silole ( M1 ) with (Z)?1,3‐bis(4‐ethynylphenyl)?3‐hydroxyprop‐en‐1‐one ( M2 ) via typical Sonogashira coupling reaction. The β‐diketonate unit in the main chain backbone of P‐1 can further coordinate with Eu(TTA)_x [TTA^? = 4,4,4‐trifluoro‐1‐(thiophen‐2‐yl)butane‐1,3‐dionate anion, X = 1, 2, 3] to afford corresponding Eu(III)‐containing polymer complexes. The resulting achiral polymer complex P‐2 (X = 2) can exhibit strong circular dichroism (CD) response toward both N‐Boc‐l and d‐ proline enantiomers. The CD signal was preliminarily attributed to coordination induction between chiral N‐Boc‐proline and the Eu(III) complex moiety. The linear regression analysis of CD sensing shows a good agreement between the magnitude of molar ellipticity and concentration of chiral N‐Boc‐l or d‐ proline, which indicates this kind Eu(III)‐containing achiral polymer complex can be used as a chiral probe for enantioselective recognition of N‐Boc‐l or d‐ proline enantiomers based on Cotton effect of CD spectra. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 3080–3086     

An improved exponential transformation for nearly singular boundary element integrals in elasticity problems

This paper presents an improved exponential transformation for nearly singular boundary element integrals in elasticity problems. The new transformation is less sensitive to the position of the projection point compared with the original transformation. In our work, the conventional distance function is modified into a new form in the polar coordinate system. Based on the refined distance function, an improved exponential transformation is proposed in the polar coordinate system. Moreover, to perform integrations on irregular elements, an adaptive integration scheme considering both the element shape and the projection point associated with the improved transformation is proposed. Furthermore, when the projection point is located outside the integration element, another nearest point is introduced to subdivide the integration elements into triangular or quadrilateral patches of fine shapes. Numerical examples are presented to verify the proposed method. Results demonstrate the accuracy and efficiency of our method.     

Laser output of radial-slab solid-state laser

In this letter, numerical simulation and experimental study of a radial-slab solid-state laser are presented. The laser includes four crossing-slabs pumped by four Xe flashlamps. The numerical simulation of coherent intensity in the near field and the far field indicates that the laser with the structure can improve the quality of output beam compared with incoherent beam combination. The radial-slab solid-state laser is fabricated, and initial experiments are carried out at a pulse repetition of 1 Hz. Nine beams in the near field and one combined beam in the far field are obtained in our initial experiment. The experimental results are consistent with the numerical analysis in the coherent condition. The results show that coherent beam combination is obtained by this laser.     

New correlation equations for predicting filter coefficient ratio of submicron particles at high ionic strength when the diffusiophoretic effect is considered

New correlation equations for the deep-bed filtration, including the term of diffusiophoresis, in addition to the Derjaguin and Landau, Verwey and Overbeek interactions, the Brownian diffusion and the interception, for predicting the initial collection efficiency under the favorable deposition condition and the filter coefficient ratio under the unfavorable deposition condition are derived by using the Brownian dynamics-simulation method. These new correlation equations for predicting the filter coefficient ratio are able to describe previous experimental results especially well for those submicron particles that are at high ionic strength.     

A moving particle semi‐implicit method for free surface flow: Improvement in inter‐particle force stabilization and consistency restoring

The moving particle semi‐implicit (MPS) method has been widely applied in free surface flows. However, the implementation of MPS remains limited because of compressive instability occurred when the particles are under compressive stress states. This study proposed an inter‐particle force stabilization and consistency restoring MPS (IFS‐CR‐MPS) method to overcome this numerical instability. For inter‐particle force stabilization, a hyperbolic‐shaped quintic kernel function is developed with a non‐negative and smooth second order derivative to satisfy the stability criterion under compressive stress state. Then, a contrastive study is conducted on the contradiction between the common understanding of the conventional MPS hyperbolic‐shaped kernel function and its performance. The result shows that the conventional MPS hyperbolic‐shaped kernel function can easily cause violent repulsive inter‐particle force and then lead to the compressive instability. Therefore, the first order derivative of the modified hyperbolic‐shaped quintic kernel function is recommended as the form of the contribution of the neighbor particles to achieve a more stable inter‐particle repulsive force. For consistency restoring, the Taylor series expansion and the hyperbolic‐shaped quintic kernel are combined to improve the accuracy of the viscosity and pressure calculation. The IFS‐CR‐MPS algorithm is subsequently verified by the inviscid hydrostatic pressure, jet impacting, and viscous droplet impacting problems. These results can be used for choosing kernel function and the contribution of neighbor particles in particle methods. Copyright © 2016 John Wiley & Sons, Ltd.     

Preparation and Characterization of Chitosan-Blended Multiwalled Carbon Nanotubes

Composites comprised of chitosan (CS) and multiwalled carbon nanotubes (MWCNTs) were fabricated by milling and ultrasonication dispersion methods. Scanning electron microscopy images showed homogeneous dispersion of MWCNTs throughout the CS matrix for samples prepared by either ultrasonication or milling methods. Further, the crystallinity of the CS component was found to decrease with the addition of MWCNTs, although the decomposition temperature and the storage modulus (E′) of the samples were improved. The decomposition temperature for the composite prepared by milling was 7°C higher than that by the ultrasonication. Meanwhile, the E′ decreased relatively slowly with temperature in the dynamic mechanical analysis measurements. In addition, IR analysis implied an interaction between CS and MWCNTs, which likely originated from hydrogen bonds between the amino, hydroxyl, and carboxyl groups of the two components. Compared with the ultrasonication, milling was more effective to promote the formation of the hydrogen bonds between CS and the MWCNTs and thus enhance the thermal stability of CS.