Effect of carriers on deposition morphologies and catalytic performances of NiCo2O4

In this study, NiCo₂O₄ with different morphologies were fabricated using carriers by homogeneous coprecipitation combined with a sintering method. The phase and microstructure were characterized by XRD, SEM, EDS, TEM and BET, and the catalytic performances were investigated by NaBH₄ hydrolysis experiments. These studies revealed that the deposition morphology of NiCo₂O₄ can be adjusted by using different kinds of carrier templates, and the supported NiCo₂O₄ samples presented the pine-needle-like, network-like, ball-cactus-like and dandelion-like morphologies respectively. The optimal catalytic activity, durability and stability make the network-like NiCo₂O₄ an appropriate catalyst for hydrogen generation of NaBH₄ hydrolysis. It was found that the network-like NiCo₂O₄ is the most reusable and durable catalyst for ten consecutive cycles and 100% hydrogen generation conversion rate without obvious decrease among these morphologies.     

木塑建筑模板

本文简要介绍了木塑建筑模板的发展概况,以及木塑建筑模板的一些特点和生产工艺,对木塑建筑模板的发展提出了一些自己的建议。     

Controlled hierarchical porosity of hybrid ceramics by leaching water soluble templates and pyrolysis

Hybrid ceramics, polysiloxane-derived materials, feature adjustable surface characteristics and high specific surface areas, making the material promising for applications such as gas separation. For increased permeability in gas separation processes or accessibility of active sites, additional porosity on multiple length scales is desired. In this study, we demonstrate how water soluble templates can be utilized to obtain a controlled hierarchical porosity. KCl sieving fractions are used for adjusting the macroporosity and a polysiloxane precursor, aminopropyltriethoxysilane, to create mesopores. The generation of micro- and mesopores is characterized by nitrogen adsorption while the macroporosity is examined by scanning electron microscopy and mercury intrusion. Water and n-heptane vapor sorption experiments show the control of the surface characteristics of the material by the pyrolysis temperature. In summary, leaching of water soluble templates for meso- and macropores combined with micro pore generation by pyrolytic decomposition enables pore size control on three different length scales.     

Influence of annealing porous templates in an ammonia atmosphere on gallium nitride growth behaviors in hydride vapor phase epitaxy

Porous templates were fabricated by hydrogen-etching metal organic chemical vapor deposited gallium nitride (GaN); these templates were used as substrates for the growth of GaN via hydride vapor phase epitaxy. The influence of annealing porous templates on GaN growth behavior was investigated. GaN epitaxied on the unannealing porous template followed the Volmer–Weber mode with the void preserved at the growth plane, whereas the GaN film on the annealed porous templates exhibited a layer-by-layer growth and filled the porous material. The GaN crystal quality was characterized by high-resolution XRD and CL, the results indicated that GaN grown with pores preserved at the template interface had a lower dislocation density than that grown with pores filled, and the best GaN film had a TD density of 10⁴ cm⁻².     

Robust object tracking based on adaptive templates matching via the fusion of multiple features

Moving object tracking under complex scenes remains to be a challenging problem because the appearance of a target object can be drastically changed due to several factors, such as occlusions, illumination, pose, scale change and deformation. This study proposes an adaptive multi–feature fusion strategy, in which the target appearance is modeled based on timed motion history image with HSV color histogram features and edge orientation histogram features. The variances based on the similarities between the candidate patches and the target templates are used for adaptively adjusting the weight of each feature. Double templates matching, including online and offline template matching, is adopted to locate the target object in the next frame. Experimental evaluations on challenging sequences demonstrate the accuracy and robustness of the proposed algorithm in comparison with several state-of-the-art algorithms.     

微流控模板法制备功能化非球形微颗粒研究新进展

功能化非球形微颗粒在生物医药、吸附、传感与检测等方面具有非常广泛的应用。相对于其他非球形微颗粒制备方法，近年来兴起的微流控技术，由于对微尺度流体具有超灵敏的操控特性，在制备和精确调控微米级功能材料方面具有很大的优势。通过精确控制流体在微尺度通道内的流动和剪切，微流控技术可以实现多种形态和结构的微尺度流体、乳液和纤维的可控构建，为非球形微颗粒的可控制造提供了优良的模板。同时，通过在制备过程中引入功能性材料，这些非球形微颗粒将具备更多的功能，从而极大地拓展和丰富了其应用范围。本文综述了近年来采用微流控技术制备功能化非球形微颗粒的研究新进展，重点介绍了以微流控技术构建得到的微流体、多相乳液及微纤维为模板可控制备功能化非球形微颗粒的研究现状。     

Mechanism of formation of polyaniline flakes with high degree of crystallization using a soft template in the presence of cetyltrimethy‐lammonium bromide

Flake‐like polyaniline with various thicknesses was prepared by cationic emulsion polymerization of aniline monomer in the presence of cetyltrimethylammonium bromide (CTAB). The morphology of polyaniline with uniform and smooth flake‐like structure was observed using field‐emission scanning electron microscopy and transmission electron microscopy. The lamellar complex of (CTA)₂S₂O₈, acting as a reactive soft template for the formation of polyaniline, was investigated using low‐angle X‐ray diffraction. The soft template provides an expanding space for the growth of polyaniline, in which the oxidization of aniline monomers can construct effectively a flake‐like structure. The concentration of CTAB plays an important role in adjusting the d‐spacing of the soft template. Crystallization and composition of polyaniline were characterized using X‐ray diffraction and Fourier transform infrared spectroscopy. The X‐ray diffraction pattern has a sharp peak at 2θ = 6.4° (d‐spacing = 13.7 Å), showing that polyaniline has a solid‐state ordering structure and high degree of crystallization. Doping and dispersive experiments were also included in the study. Copyright © 2012 Society of Chemical Industry     

[2.2]Paracyclophane as a Target of the Organic Solid State: Emergent Properties via Supramolecular Construction

In this account, we review the synthesis of [2.2]paracyclophanes in the organic solid state. Reactions in crystalline solids provide a means to obtain molecules with high degrees of stereocontrol that can also be unattainable in solution. We show that [2.2]paracyclophanes form in the solid state stereospecifically and in quantitative yield via intermolecular [2+2] double photodimerization reactions. The double cycloaddition that affords a paracyclophane in the solid state does not readily occur in solution. Small molecules in the form of hydrogen-bond-donor templates can provide access to [2.2]paracyclophanes in a solid by design. A [2.2]paracyclophane obtained using a hydrogen-bond template is shown to exhibit attractive optical properties and has been employed as a building block of a metal-organic framework (MOF).