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The creation of intergrown layer-like zeolite crystals is one route to form hierarchical zeolites. Faujasite-type (FAU-type) zeolites are among the industrially most important zeolites and the implementation of hierarchical porosi...
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The creation of intergrown layer-like zeolite crystals is one route to form hierarchical zeolites. Faujasite-type (FAU-type) zeolites are among the industrially most important zeolites and the implementation of hierarchical porosity is a promising way to optimise their catalytic and adsorptive performance. After a short general survey into routes for the preparation of hierarchical pore systems in FAU, we will review the currently existing strategies for the synthesis of FAU with layer-like morphology. Those strategies are mainly based on the presence of morphology modifying agents in the synthesis mixture. However, a very recent approach is the synthesis of layer-like FAU-type zeolite crystals assembled in an intergrown manner in the absence of such additives, just by finely adjusting the crystallization temperature. This additive-free preparation route for layer-like FAU, which appears very attractive from an ecological as well as economic point of view, is highlighted in this review. Concluding, a comparison, including powder X-ray diffraction, scanning and transmission electron microscopy, nitrogen physisorption and elemental analysis, between conventional FAU and three layer-like FAU obtained by different synthesis routes was carried out to show the structural, morphological and textural differences and similarities of these materials.
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It is known that Mg-Al layer double hydroxide (Mg-Al LDH) possesses plate-like morphology if carefully crystallized. This work focuses on the preparation of Co-Ti LDH having fibrous morphology or mixture of plate-like and fibrous ...
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It is known that Mg-Al layer double hydroxide (Mg-Al LDH) possesses plate-like morphology if carefully crystallized. This work focuses on the preparation of Co-Ti LDH having fibrous morphology or mixture of plate-like and fibrous morphologies. The Co-Ti LDH obtained by precipitation for relatively short aging time showed plate-like morphology. By increasing aging time, the plate-like morphology was transformed into fibrous morphology. The percentage of titanium also played an important role to determine the morphology of Co-Ti LDH. The samples having low percentage of titanium 20% and 17% showed plate-like morphology with a small amount of fibrous morphology if prepared from cobalt nitrate. However, the sample having high percentage of titanium 27% showed a large amount of fibrous morphology with a small amount of plate-like morphology. In the sample having 24% of titanium, SEM images showed needles morphology. Furthermore, in the sample prepared from cobalt chloride with low percentage of titanium 17%, the SEM images show the production of a large amount of fibrous morphology.
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The incorporation of different types of buffer layers has demonstrated to improve the efficiency of Cu_2ZnSnS_4 (CZTS) thin film solar cells. The materials tested as buffer layers were Cadmium Sulphide (CdS), Zinc Sulphide (ZnS) a...
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The incorporation of different types of buffer layers has demonstrated to improve the efficiency of Cu_2ZnSnS_4 (CZTS) thin film solar cells. The materials tested as buffer layers were Cadmium Sulphide (CdS), Zinc Sulphide (ZnS) and Cadmium Zinc Sulphide (Cd_(7.23)Zn_(2.77)S_(10)). The effect of the buffer layer and the absorber layers on the structural, morphological and optical properties of the films was studied. As grown CZTS thin films made with SILAR method were annealed at 550 °C in the sulfur atmosphere for 60 min to improve the crystallinity of the material. X-ray diffraction (XRD) and Raman studies confirm the formation of kesterite structure in CZTS thin film. CdS, ZnS and Cd_(7.23)Zn_(2.77)S_(10) thin films also confirm crystalline nature with crystallite sizes being 9 nm, 13 nm and 14 nm respectively. Leaf, flower and petal−like morphologies of CdS, ZnS and Cd_(7.23)Zn_(2.77)S_(10) thin films respectively have been confirmed by Field Emission Scanning Electron Microscopy (FESEM). The electrical properties of the completed CZTS solar cells were also examined. From the obtained J-V characteristic curves upon illumination of the heterojunction solar cells, we calculated the power conversion efficiency to be 0.76%, 1.00% and 1.24% for the FTO/ZnO/ZnS/CZTS/Ag, FTO/ZnO/CdS/CZTS/Ag and FTO/ZnO/Cd_(7.23)Zn_(2.77)S_(10)/CZTS/Ag respectively.
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Using direct-current and pulsed cathode arc plasma technique, diamond-like carbon(DLC) bilayer films with Cu functional layer(interlayer and surface layer) were prepared on silicon substrate and annealed at various temperatures in...
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Using direct-current and pulsed cathode arc plasma technique, diamond-like carbon(DLC) bilayer films with Cu functional layer(interlayer and surface layer) were prepared on silicon substrate and annealed at various temperatures in vacuum. The effects of Cu functional layer and annealing temperature on the structure, morphology and mechanical properties of the films were investigated. The results showed that Cu functional layer changed the bilayers microstructure, including the size of sp 2 carbon clusters and the thickness and element distribution of diffusion layer. A simple three-layer model was used to describe the interdiffusion between Cu and C layers. Cu interlayer facilitated the graphitic rearrangement in bilayer films due to weak Cu/C bonds and Cu surface layer could be more effective against graphitization. Cu/DLC and DLC/Cu bilayers showed highly dispersed nano-agglomerates on the surface, and the particle size and surface roughness of the bilayers were largely affected by annealing temperature. The hardness and stress of the bilayer were dependent on the location of Cu functional layer. DLC/Cu bilayer possessed a relatively higher hardness and a lower stress at low annealing temperature of 100-400°C. The results may be of interest for studying the relaxation of stress in the DLC bilayer films and can be used in advancing the development of DLC based engineering materials with high mechanical properties.
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The present research discussed the utilization of layered double hydroxides (LDH) materials with different morphologies as adsorbents for Methyl Orange (MO) removal from aqueous solution. The adsorption properties of LDH with flow...
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The present research discussed the utilization of layered double hydroxides (LDH) materials with different morphologies as adsorbents for Methyl Orange (MO) removal from aqueous solution. The adsorption properties of LDH with flower-like morphology (f-LDH) have been investigated for azo dye, Methyl Orange (MO), and compared to conventional stone-like coprecipitated LDH phases(c-LDH). Flower-like LDH with high specific surface area of 133 m(2)/g were synthesized by coprecipitation method in dilute alkaline solution. With relatively high specific surface areas, the as-prepared flower-like LDH, when tested as adsorbents in azo dye removal, showed excellent performance and were better than those of conventional coprecipitated LDH. The adsorption isotherms, kinetics and mechanisms for azo dye MO onto as-prepared flower-like LDH were also investigated. The high uptake capability of the as-prepared flower-like adsorbents 500.6 mg of MO/g of LDH make them potentially attractive adsorbents in water purification avoiding calcination step. Hence, a low cost material will be acquired with much more benefits namely preserving energy. (C) 2017 Elsevier B.V. All rights reserved.
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Cryogenic transmission electron microscopy (cryo-TEM) studies were performed to probe the morphological structure of aggregates formed by the two near-infrared dyes IR-140 and Indocyanine Green (ICG) in water. Both dyes formed she...
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Cryogenic transmission electron microscopy (cryo-TEM) studies were performed to probe the morphological structure of aggregates formed by the two near-infrared dyes IR-140 and Indocyanine Green (ICG) in water. Both dyes formed sheet-like monolayered J-aggregates of mesoscopic size. This structure is consistent with a stacking geometry known for other cyanine dye J-aggregates. H-aggregates, which dominate in freshly prepared aqueous ICG solutions, proved to be linear aggregates of mesoscopic size that are characterized by a broad size distribution. Besides small oligomer particles up to tens of nanometers long thread-like aggregates were detected.
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Mild steel was coated by hot-dipping into a molten aluminum bath. The microstructure and phase evolution in the aluminide layer during diffusion at 750℃ in static air were analyzed by electron backscatter diffraction (EBSD). The ...
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Mild steel was coated by hot-dipping into a molten aluminum bath. The microstructure and phase evolution in the aluminide layer during diffusion at 750℃ in static air were analyzed by electron backscatter diffraction (EBSD). The results showed that the aluminide layer of the as-coated specimen consisted of an outer aluminum topcoat, minor FeAb and major Fe_2Al_5, respectively. Also, Fe_2Al_5 possessed a tongue-like morphology, which caused corresponding serration-like morphology in the steel substrate. A portion of the peaks of serration-like substrate were isolated, after short exposure at 750℃, and accompanied by the formation of voids, which continued to appear with further exposure at 750 ℃. As the aluminum topcoat was consumed, FeAl_3 phase disappeared and left an aluminide layer of Fe_2Al_5 phase. After 60 min of exposure, FeAl_2 and FeAl phases formed at the interface between Fe_2Al_5 and the steel substrate. With increasing exposure time, the voids condensed and the serration-like morphology disappeared, while FeAl_2 and FeAl phases kept growing. After prolonged exposure, the aluminide layer was composed of and FeAl and possessed a flat interface between FeAl and steel substrate.
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Mild steel was coated by hot-dipping in a molten aluminum bath. The growth behavior in the intermetallic layer after various times of immersion in the hot-dip at 700 degrees C was analyzed by electron backscatter diffraction (EBSD...
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Mild steel was coated by hot-dipping in a molten aluminum bath. The growth behavior in the intermetallic layer after various times of immersion in the hot-dip at 700 degrees C was analyzed by electron backscatter diffraction (EBSD). The results showed that the aluminide layer consisted of an outer aluminum topcoat, minor FeAl3 and major Fe2Al5, respectively. From another perspective, Fe2Al5 possessed a tongue-like morphology, which caused the corresponding serration-like morphology of the steel substrate. The Fe-Al/steel substrate interface of the Fe2Al5 phase, after removal of the steel substrate, displayed a columnar structure growing toward the steel substrate, implying that Fe2Al5 grew at a rapid rate along the diffusion direction. Moreover, the EBSD results revealed the Fe2Al5 phase was not only composed of columnar grains, but also possessed fine grains clustered around the peaks of the serration-like steel substrate.
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The morphology and ultrastructure of the female reproductive system were examined for a larval-pupal parasitoid Trichomalopsis shirakii Crawford of Oulema oryzae Kuwayama using light and electron microscopes. The reproductive syst...
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The morphology and ultrastructure of the female reproductive system were examined for a larval-pupal parasitoid Trichomalopsis shirakii Crawford of Oulema oryzae Kuwayama using light and electron microscopes. The reproductive system includes two ovaries, two pairs of accessory glands, an unbranched venom gland, a large venom reservoir and a Dufour gland. Each ovariole contains follicles and oocytes at different stages of maturation. A fibrous layer covers the surface of mature egg. The accessory glands are made up of a layer of secretory cells surrounded by muscle fibers. In these secretory cells, numerous mitochondria, electron-dense secretory granules and vesicles filled with dense granular particles are present. These granular particles appear as virus-like particles (VLPs). The venom gland consists of a single layer of secretory cells which are organelle rich with abundant rough endoplasmic reticulum, mitochondria and vesicular organelles, a layer of duct cells and an inner intima. The reservoir consists of a muscular sheath, epidermal cells with few organelles and an intima layer. The Dufour gland has a relatively large lumen surrounded by a single layer of columnar epithelial cells which are characterized by clusters of smooth endoplasmic reticulum and lipid droplets. Aside from the venom, the fibrous layer coating the egg and the granular particles which may be VLPs have been discovered in our study. They may serve as one of the parasitoid-associated factors in their host-parasitoid relationship and play a role in host immune suppression. (C) 2016 Wiley Periodicals, Inc.
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Developing an efficient, clean, sustainable, and reliable energy storage system is still a key challenge to resolve the growing demands of energy consumption. In this regard, supercapacitor becomes one of the foremost promising an...
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Developing an efficient, clean, sustainable, and reliable energy storage system is still a key challenge to resolve the growing demands of energy consumption. In this regard, supercapacitor becomes one of the foremost promising and emerging types of energy storage systems comprising properties of traditional batteries and conventional capacitors. Herein, a binder-free composite electrode of Al(OH)(3)/MnO2/FeOOH (AMFO) has been synthesized on stainless steel substrate via a facile, eco-friendly, and cost-effective Layer by Layer method at room temperature. The high resolution scaning electron microscopy reveals the mesoporous reindeer moss-like morphology of the synthesized electrode. The super-capacitive behaviour of the synthesized electrode has been explored in 1 M Na2SO4 electrolyte solution by using electrochemical measurement. The highest specific capacity of 2557 C g(-1) has been obtained at a scan rate of 5 mV s(-1) having wide potential range (similar to 1.10 to 1.05 V). Further, a symmetric prototype supercapacitive device has been fabricated by coupling the AMFO electrodes. The high specific capacitance of 511 F g(-1) has been obtained with ultra-high energy and power densities of similar to 443 Wh kg(-1) and similar to 13 kWkg(-1), respectively. These results indicate that this electrode has potential practical applications as a power backup, portable electronic device, and energy storage system. (c) 2021 Elsevier Ltd. All rights reserved.
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