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.     

A Novel One-Pot Synthesis of Fluorinated α,β-Unsaturated Esters

The reaction of pentafluorophenylmethylene-triphenylarsorane or p-chloro-tetrafluorophenylmethyl-enetriphenylarsorane, generated in situ from methylene-triphenylarsorane and hexafluorobenzene or chloropenta-fluorobenzene, with bromoacetates giving excellent yields of 3-pentafluorophenyl or 3-p-chloro-tetrafluoro-phenyl α, β-unsaturated esters with high steroselectivity is described.     

New designed DNA light switch Ruthenium complexes as DNA photocleavers and Topoisomerase I inhibitors

Two ruthenium complexes containing a new ligand phipz (phipz = 2‐(1,10‐phenanthroline)‐1H‐imidazo[4,5‐b]phenazine) were designed and synthesized. These complexes were found to inhibit the DNA supercoiled relaxation mediated by topoisomerase I (topo I), cleave DNA under irradiation and bind to calf thymus DNA through intercalative mode. Furthermore, complex 2 shows higher photocleavage activity, topo I inhibition activity and DNA affinity than complex 1 . Additionally, introduction of phenazine unit may be the reason that two complexes exhibit DNA ‘light switch’ behavior. The present work shows that two complexes might be potential as new DNA ‘light switches’, DNA photocleavers and topo I inhibitors.     

Effects of substituents on bridging ligands on the single‐molecule magnet properties of Zn2Dy2 cluster complexes

Two new Zn₂Dy₂ complexes were constructed from Zn (II) salen‐type Schiff base complex fragment and 2,6‐pyridinedimethanol (H₂pdm) or its Br‐substituted analogue (4‐bromopyridine‐2,6‐diyl)dimethanol (H₂Brpdm); their molecular formulas are [Zn₂Dy₂(L)₂(pdm)₂(MeOH)₂](ClO₄)₂ [ 1 , H₂L = N, N′‐ bis(3‐methoxysalicylidene)‐1,3‐diaminopropane] and [Zn₂Dy₂(L)₂(Brpdm)₂(MeOH)₂](ClO₄)₂ [ 2 ], the Dy (III) ions of which have a NO₇ triangular dodecahedral coordination sphere. The two complexes show not only ferromagnetic interaction but also field‐induced single‐molecule magnet (SMM) behavior, which are rare Dy (III)‐containing cluster complexes with the NO₇ triangular dodecahedral coordination sphere that can show good magnetic relaxation. The energy barrier value of complex 2 is higher than those of complex 1 and the Dy (III) complexes with the DyNO₇ triangular dodecahedral coordination configuration reported in the literature.     

Probing nanocolumnar silver nanoparticle/zinc oxide hierarchical assemblies with advanced surface plasmon resonance and their enhanced photocatalytic performance for formaldehyde removal

Recent advances in photocatalysis focus on the development of materials with hierarchical structure and on the surface plasmon resonance (SPR) phenomenon exhibited by metal nanoparticles (NPs). In this work, both are combined in a material where size‐controllable Ag‐NPs are uniformly loaded onto the hierarchical microporous and mesoporous and nanocolumnar structures of ZnO, resulting in Ag‐NP/ZnO nanocomposites. The embedded Ag‐NPs slightly decrease the hydrophobicity of fibrous ZnO, improve its wettability, and increase the absorption of formaldehyde (H₂CO) onto the photocatalyst, all of this resulting in excellent photodegradation of formaldehyde in aqueous solution. Besides, we found that Ag‐NPs with optimal size not only accelerate the charge transfer to the surface of ZnO, but also strengthen the SPR effect in the intercolumnar channels of fibrous ZnO particles combining with high concentration of photo‐generated radical species. The micro‐to‐mesoporous ZnO is like a nanoarray packed Ag‐NPs. With Ag‐NPs of diameter 2.5 < ? < 6.5 nm, ZnO exhibits the most superior photodegradation rate constant value of 0.0239 min^?1 with total formaldehyde removal of 97%. This work presents a new feasible approach involving highly sophisticated Ag‐NP/ZnO architecture combining the SPR effect and hierarchically ordered structures, which results in high photocatalytic activity for formaldehyde photodegradation.     

Vertically Grown Few-Layer MoS2 Nanosheets on Hierarchical Carbon Nanocages for Pseudocapacitive Lithium Storage with Ultrahigh-Rate Capability and Long-Term Recyclability

Molybdenum disulfide (MoS₂) is an intensively studied anode material for lithium-ion batteries (LIBs) owing to its high theoretical capacity, but it is still confronted by severe challenges of unsatisfactory rate capability and cycle life. Herein, few-layer MoS₂ nanosheets, vertically grown on hierarchical carbon nanocages (hCNC) by a facile hydrothermal method, introduce pseudocapacitive lithium storage owing to the highly exposed MoS₂ basal planes, enhanced conductivity, and facilitated electrolyte access arising from good hybridization with hCNC. Thus, the optimized MoS₂/hCNC exhibits reversible capacities of 1670 mAh g⁻¹ at 0.1 A g⁻¹ after 50 cycles, 621 mAh g⁻¹ at 5.0 A g⁻¹ after 500 cycles, and 196 mAh g⁻¹ at 50 A g⁻¹ after 2500 cycles, which are among the best for MoS₂-based anode materials. The specific power and specific energy, which can reach 16.1 kW and 252.8 Wh after 3000 cycles, respectively, indicate great potential in high-power and long-life LIBs. These findings suggest a promising strategy for exploring advanced anode materials with high reversible capacity, high-rate capability, and long-term recyclability.