Solution-based processing of carbon nitride composite for boosted photocatalytic activities

Thanks to the dissolution of bulk carbon nitride (CN), a heterojunction of CN and sulfur-doped CN was constructed via a solution-based processing way, which led to a more homogeneous composite and an improved photocatalytic H₂ production activity up to 230% with respect to that by conventional impregnating.     

On complete intersections with trivial canonical class

We prove birational boundedness results on complete intersections with trivial canonical class of base point free divisors in (some version of) Fano varieties. Our results imply in particular that Batyrev–Borisov toric construction produces only a bounded set of Hodge numbers in any given dimension, even as the codimension is allowed to grow.     

A novel block copolymer with excellent amphiphobicity synthesized via ARGET ATRP

The poly(methyl methacrylate)‐b‐poly(2‐[[[[2‐(perfluorohexyl)]‐sulfonyl]‐amino]ehthyl] methacrylate) (PMMA‐b‐PC₆SMA) copolymers were successfully synthesized for the first time using activator regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) method. Under optimized reaction conditions, the degree of polymerization (DP) of resulting copolymers increased approximately linearly with monomer conversion. Structures of a well‐defined block copolymer were determined by GPC, FT–IR, and ¹H‐NMR spectra. Results from AFM and contact angle measurements of polymer films revealed the presence of block segments derived from PC₆SMA, as indicated by the obvious increase in hydrophobicity and oleophobicity. The relationship between surface composition and surface wetting ability was confirmed by XPS and AFM spectra. Compared with the random copolymer PMMA‐co‐PC₆SMA, C₆SMA dosages in the PMMA‐b‐PC₆SMA copolymers were greatly decreased, which retained its hydrophobic and oleophobic properties. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 2040–2049     

Hydrosilylation in Aryliminopyrrolide‐Substituted Silanes

A range of silanes was synthesized by the reaction of HSiCl₃ with iminopyrrole derivatives in the presence of NEt₃. In certain cases, intramolecular hydrosilylation converts the imine ligand into an amino substituent. This reaction is inhibited by factors such as electron‐donating substitution on Si and steric bulk. The monosubstituted (^DippIMP)SiHMeCl (^DippIMP=2‐[N‐(2,6‐diisopropylphenyl)iminomethyl]pyrrolide), is stable towards hydrosilylation, but slow hydrosilylation is observed for (^DippIMP)SiHCl₂. Reaction of two equivalents of ^DippIMPH with HSiCl₃ results in the hydrosilylation product (^DippAMP)(^DippIMP)SiCl (^DippAMP=2‐[N‐(2,6‐diisopropylphenyl)aminomethylene]pyrrolide), but the trisubsitituted (^DippIMP)₃SiH is stable. Monitoring the hydrosilylation reaction of (^DippIMP)SiHCl₂ reveals a reactive pathway involving ligand redistribution reactions to form the disubstituted (^DippAMP)(^DippIMP)SiCl as an intermediate. The reaction is strongly accelerated in the presence of chloride anions.     

Copolymers of fluorene and thiophene with conjugated side chain for polymer solar cells: Effect of pendant acceptors

Two copolymers of fluorene and thiophene with conjugated side‐chain pending acceptor end group of cyanoacetate ( P2 ) and malononitrile ( P3 ) were synthesized. Both polymers exhibit good thermal stability and low highest occupied molecular orbital level (?5.5 eV). In comparison with P2 , P3 exhibits stronger UV–vis absorption and higher hole mobility. Polymer solar cells based on P3 :PC₇₁BM exhibits a power conversion efficiency of 1.33% under AM 1.5, 100 mW/cm², which is three times of that based on P2 :PC₇₁BM. The higher efficiency is attributed to better absorption, higher hole mobility, and the reduced phase separation scale in P3 :PC₇₁BM blend. The aggregate domain size in P3 :PC₇₁BM blend is 50 nm, much smaller than that in P2 :PC₇₁BM blend (200 nm). Tiny difference in the end groups on side chains of P2 and P3 leads to great difference in phase separation scale, charge transport, and efficiency of their photovoltaic devices. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

A micromechanics model for FRC composites

A multiscale model for FRC composite structures taking into consideration the complex interactions at the scales of the fiber and microcracks is proposed. At the scale of the single fiber, a semi-analytical model characterizes the microslip behavior at the interface between the matrix and the fiber in terms of the overall composite stresses. The influence of fiber bundles on microcrack bridging and arrest is taken into account within the framework of linear elastic fracture mechanics. Upscaling to the macroscopic level using continuum micromechanics shows that the macroscopic deformation of the FRC composite is governed by a ’TERZAGHI’ like effective stress. For the finite element analyses of failure behavior at the scale of the composite structure, an ’interface solid element’ technique is used to consider localized cracking. Selected numerical and semi-analytical results together with experimental validations are provided. (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

壳体初始形状对球形容器液压胀形结果的影响

借助于数值模拟研究了锥台形壳体液压胀形过程中可能出现的质量问题，以及壳体的初始形状对成形结果的影响，在此基础上提出了锥台形壳体的改进方案，以避免壳体的起皱，并最终获得预期的球形容器或椭球形容器。     

A class of bifurcation solutions of almost-periodic parametric vibration systems

A class of bifurcation solutions of almost-periodic (a. p. for short) parametric vibration systems is studied by Liapunov-Schmidt reduction. The bifurcation diagrams and formulas are given. The Project Supported by National Natural Science Foundation of China.     

TORSIONAL VIBRATIONS OF RIGID CIRCULAR PLATE ON TRANSVERSELY ISOTROPIC SATURATED SOIL

An analytical method was presented for the torsional vibrations of a rigid disk resting on transversely isotropic saturated soil. By Hankel transform, the dynamic governing differential equations for transversely isotropic saturated poroelastic medium were solved. Considering the mixed boundary-value conditions, the dual integral equations of torsional vibrations of a rigid circular plate resting on transversely isotropic saturated soil were established. By appropriate transform, the dual integral equations were converted into a Fredholm integral equation of the second kind. Subsequently, the dynamic compliance coefficient, the torsional angular amplitude of the foundation and the contact shear stress were expressed explicitly. Selected examples were presented to analyse the influence of saturated soil's anisotropy on the foundation's vibrations.     

边界拟合坐标系下的差分有限元破开算子法

在边界拟合坐标系下给出耦合了有限差分法和有限单元法的新型的破开算子法.利用该方法,Navier-Stokes方程被分解成对流方程和扩散方程,对流方程采用稳定性好的有限差分法求解,而扩散方程则采用有限单元法求解.由于计算是基于非均匀网格,采用边界加密的51×51网格就达到了前人在计算雷诺数为5000的方腔环流时采用的257×257均匀网格的效果,对于瑞利数Rt=107的竖腔自然对流的计算进一步表明,提出的方法是有效的.对于Re=105的高雷诺数方腔受驱环流,得到了非稳态、非周期的和带有随机特征的流场结构.