NEW ORGANIC NONLINEAR OPTICAL MATERIALS OF CINNAMYLIDENE-ACETOPHENONE DERIVATIVES

we have synthesised a series of new optically nonlinear organic materials of cinnamylidene-acetophenone derivatives which have large nonl inear optical susceptibilities and short cut-off wavelengths.

Rational Design of Star-shaped Molecules with Benzene Core and Naphthalimide Derivatives End Groups as Organic Light-emitting Materials

A series of star-shaped molecules with benzene core and naphthalimides derivatives end groups have been designed to explore their optical,electronic,and charge transport properties as charge transport and/or luminescent materials for organic light-emitting diodes（OLEDs）. The frontier molecular orbitals（FMOs） analysis has turned out that the vertical electronic transitions of absorption and emission are characterized as intramolecular charge transfer（ICT）. The calculated results show that the optical and electronic properties of star-shaped molecules are affected by the substituent groups in N-position of 1,8-naphthalimide ring. Our results suggest that star-shaped molecules with n-butyl（1）,benzene（2）,thiophene（3）,thiophene S？,S？-dioxide（4）,benzo[c][1,2,5]thiadiazole（5）,and 2,7a-dihydrobenzo[d]thiazole（6） fragments are expected to be promising candidates for luminescent and electron transport materials for OLEDs. This study should be helpful in further theoretical investigations on such kind of systems and also to the experimental study for charge transport and/or luminescent materials for OLEDs.

Shape Optimization With Sensitivity Analysis in Local Domain

For complicated geometries, it is ineflicient to integrate over the entire domain. A new approach for optimization is presented here, based on sensitivity analysis of local do- main and deformation of full domain. Accurate results of design sensitivity analysis are ob- tained with this approach in shape optimization. This method is shown to be efficient when used in optimization programs and results in less distortion of the mesh.

Co/N-doped carbon nanotube arrays grown on 2D MOFs-derived matrix for boosting the oxygen reduction reaction in alkaline and acidic media

The development of high-performance and cost-effective electrocatalysts towards oxygen reduction reaction(ORR) is of significant importance,but still challenging for the practical applications in related energy systems.ORR process typically suffers from sluggish kinetics,the exploration of ORR electrocatalyst thus requires elaborate design.Herein,an effective strategy is developed for growing Co/N-doped carbon nanotube arrays on 2D MOFs-derived matrix via the pyrolysis of Co/Zn metalorganic-framework(MOF) nanosheets.The Co/Zn-MOF nanosheets serve as both the self-template for the 2D carbonized framework morphology and C/N source for the in-situ growth of 1D N-doped carbon nanotubes.The constructed hie rarchical architecture effectively integrates the OD/1D Co nanoparticle/Ndoped carbon nanotube interface and 1D(nanotubes)/2D(nanosheets) junction into frameworks with highly exposed active surface,enhanced mass-transport kinetics and electrical conductivity.As a result,the designed composite exhibits superior ORR activity and durability in alkaline media as compared to commercial Pt/C.Particularly,it shows promising ORR performance with a half-wave potential of 0.78 V versus reversible hydrogen electrode and negligible activity attenuation after 5000 potential cycles in acidic electrolyte.The designed strategy can be extended to construct other MOFs-derived carbon matrixes with diverse hierarchical structures and provide an efficient avenue for searching highperformance electrocatalysts.

Novel strategies to tailor the photocatalytic activity of metal–organic frameworks for hydrogen generation: a mini-review

This review provides a recompilation of the most important and recent strategies employed to increase the efficiency of metal-organic framework(MOF)-based systems toward the photocatalytic hydrogen evolution(PHE)reaction through specific strategies:tailoring the photocatalytic activity of bare MOFs and guest@MOF composites,formation of heterojunctions based on MOFs and various photocatalysts,and inorganic photocatalysts derived from MOFs.According to the data reported in this mini-review,the most effective strategy to improve the PHE of MOFs relies on modifying the linkers with new secondary building units(SBUs).Although several reviews have investigated the photocatalytic activity of MOFs from a general point of view,many of these studies relate this activity to the physicochemical and catalytic properties of MOFs.However,they did not consider the interactions between the components of the photocatalytic material.This study highlights the effects of strength of the supramolecular interactions on the photocatalytic performance of bare and MOF-based materials during PHE.A thorough review and comparison of the results established that metal-nanoparticle@MOF composites have weak van der Waals forces between components,whereas heterostructures only interact with MOFs at the surface of bare materials.Regarding material derivatives from MOFs,we found that pyrolysis destroyed some beneficial properties of MOFs for PHE.Thus,we conclude that adding SBUs to organic linkers is the most efficient strategy to perform the PHE because the SBUs added to the MOFs promote synergy between the two materials through strong coordination bonds.

Implementation of Some Methods of Shape Design for Variational Inequalities

In this paper we present some results concerning the optimal shape design problem governed by the fourth-order variational inequalities. The problem can be considered as a model example for the design of the shapes for elastic-plastic problem. The computations are done by finite element method, and the performance criterion is minimized by the material derivative method. We also discuss the error estimates in the appropriate norm and present some numerical results. An example is used to clearly illustrate the essential elements of shape design problems.