Low-frequency driving of a liquid crystal display (LCD) panel to minimise power consumption has drawn much attention recently. In case an LCD panel is driven by a low-frequency fringe field, image flickering phenomenon is detected by the naked human eye when the sign of the applied electric field is reversed. We investigated the effect of electrode spacing on the image flickering phenomenon induced by the flexoelectric effect in a fringe-field-switching (FFS) liquid crystal cell. We found that the image flicker in an FFS cell under low-frequency driving can be eliminated in a simple manner by changing the electrode spacing. 相似文献
A synthesis strategy for the preparation of ultrathin free‐standing ternary‐alloy nanosheets is reported. Ultrathin Pd‐Pt‐Ag nanosheets with a thickness of approximately 3 nm were successfully prepared by co‐reduction of the metal precursors in an appropriate molar ratio in the presence of CO. Both the presence of CO and the interplay between the constituent metals provide fine control over the anisotropic two‐dimensional growth of the ternary‐alloy nanostructure. The prepared Pd‐Pt‐Ag nanosheets were superior catalysts of ethanol electrooxidation owing to their specific structural and compositional characteristics. This approach will pave the way for the design of multicomponent 2D nanomaterials with unprecedented functions. 相似文献
A cytocompatible method of surface‐initiated, activator regenerated by electron transfer, atom transfer radical polymerization (SI‐ARGET ATRP) is developed for engineering cell surfaces with synthetic polymers. Dopamine‐based ATRP initiators are used for both introducing the ATRP initiator onto chemically complex cell surfaces uniformly (by the material‐independent coating property of polydopamine) and protecting the cells from radical attack during polymerization (by the radical‐scavenging property of polydopamine). Synthetic polymers are grafted onto the surface of individual yeast cells without significant loss of cell viability, and the uniform and dense grafting is confirmed by various characterization methods including agglutination assay and cell‐division studies. This work will provide a strategic approach to the generation of living cell–polymer hybrid structures and open the door to their application in multitude of areas, such as sensor technology, catalysis, theranostics, and cell therapy. 相似文献
AbstractLiquid polybutadiene rubber (LPB) was blended with poly(lactic acid) (PLA) through reactive and non-reactive routes to enhance the toughness of the PLA. The reactively blended PLA (PBR10) was prepared by melt blending the PLA with the LPB in the presence of dicumyl peroxide (DCP), a radical initiator, while the PB10 was just melt blended without the DCP. Fourier transform infrared (FTIR) spectra and wide-angle X-ray diffraction (WAXD) patterns were used to study the molecular structure of the blends. Properties were investigated through universal testing machine (UTM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscope (SEM) analysis, and rheological measurements. The results indicated that the radical crosslinking by the DCP could increase the compatibility between the PLA and LPB and disperse the rubber particles at the nanoscale in the PLA matrix. As a result, the toughness and melt viscosity of the PLA was significantly enhanced through the reactive blending, which is promising for the practical application of the modified PLA in the area of packaging. 相似文献
An in situ bimolecular reaction, in which syngas is fed with toluene as a secondary reactant (hereafter Tol in situ methylation), was studied over bifunctional catalysts comprised of methanol synthesis catalyst and H-ZSM-5 in a fixed-bed down-flow reactor at 460 psig. When physically mixed with H-ZSM-5 to form bifunctional catalysts, CrZ_HZ (Cr2O3/ZnO + HZSM-5) catalyst showed much higher activity than CZA_HZ (CuO/ZnO/Al2O3 + H-ZSM-5) in the Tol in situ methylation, while CrZ catalyst exhibited substantially lower activity than CZA in methanol synthesis. CO conversion to methanol in the Tol in situ methylation was estimated by Bz in situ methylation. The CO conversion to methanol was calculated to be in the range of 11–27 %, while that in methanol synthesis over CrZ was about 5 % at most due to chemical equilibrium limitation. By employing a silicalite-coated H-ZSM-5 (Sil/HZ) in bifunctional catalyst, xylene selectivity and para-xylene yield were much improved in the Tol in situ methylation. 相似文献
The effect of K on the activities of Ni/Al2O3 catalysts in steam reforming of ethylene glycol was investigated. Ni/Al2O3 catalysts were prepared by incipient wetness impregnation and co-precipitation methods. The addition of K was achieved using an incipient wetness impregnation method. The prepared catalysts were characterized by N2 physisorption, inductively coupled plasma-atomic emission spectroscopy, X-ray diffraction, temperature-programmed reduction, and scanning electron microscopy. Irrespective of the preparation method, the promotional effect of K was observed and the optimum K content (~5 wt%) was verified for K-promoted Ni/Al2O3 catalysts. The addition of K to the Ni–Al2O3 catalyst prepared by co-precipitation led to higher catalytic activity than addition of K to the Ni/Al2O3 catalyst prepared by incipient wetness impregnation. 相似文献
The aim of this study is to establish the safe and effective ocular delivery system of therapeutic small interfering RNA (siRNA) in corneal neovascularization therapy. The major hurdle present in siRNA‐based corneal neovascularization (CNV) therapy is severe cytotoxicity caused by repetitive drug treatment. A reducible branched polyethylenimine (rBPEI)‐based nanoparticle (NP) system is utilized as a new siRNA carrier as a hope for CNV therapy. The thiolated BPEI is readily self‐crosslinked in mild conditions to make high molecular weight rBPEI thus allowing the creation of stable siRNA/rBPEI nanoparticles (siRNA‐rBPEI‐NPs). In the therapeutic region, the rBPEI polymeric matrix is effectively degraded into nontoxic LMW BPEI inside the reductive cytosol causing the rapid release of the encapsulated siRNA into the cytosol to carry out its function. The fluorescent‐labeled siRNA‐rBPEI‐NPs can release siRNA into the entire corneal region after subconjuctival injection into the eye of Sprague Dawley rats thus confirming the proof of concept of this system.