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CaF<sub>2</sub> Nanocrystals Synthesis That Have a Unique Shape
摘要： CaF2 nanocrystals with a clear cubic shape were synthesized using both simple mixing and a hydrothermal method that neither of which required the use of surfactants or dispersants. The concentration and pH of the reaction medium, which in this case was an aqueous HNO3 solution, was found to be very important for determining the morphology of the CaF2 particles.
关键词： nanocrystal,solvothermal reaction,CaF2,morphology control
更新于2025-09-10 09:29:36
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Ti3+-doped TiO2(B)/anatase spheres preparedusingthioglycolic acid towards super photocatalysis performance
摘要： A high efficiency photocatalyst, TiO2(B)/anatase spheres consisted of nanosheets were prepared. Thioglycolic acid (TGA) was added into the precursor to control the hydrolysis process of titanium source (TiCl3), which is a key to adjust the microstructure of products. The results indicated that TGA-modified samples revealed enhanced photocatalysis performance compared with the one without TGA. The photocatalysis performance of TGA-modified sample is about 15 times high compared with commercial P25. This is ascribed to mixed crystal phase and lattice distortion which resulted in more activity sites (e.g. Ti3+ and oxygen defects). The loading of Au nanoparticles in different ways confirms that rich Ti3+-oxygen vacancies on the surface of samples caused super photocatalytic performance.
关键词： Phase,Morphology,Photocatalysis,TiO2
更新于2025-09-10 09:29:36
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Application of N-TiO2 for visible-light photocatalytic degradation of Cylindrospermopsis raciborskii — More difficult than that for photodegradation of Microcystis aeruginosa ?
摘要： Nowadays Cylindrospermopsis raciborskii (C. raciborskii) and the metabolites produced, such as cylindrospermopsin (CYN), pose a serious threat to the ecosystem. Advanced oxidation technologies have been verified as constituting a very promising means to eliminate the risk from harmful algae. But so far little research has focused on the visible-light photocatalytic destruction of C. raciborskii cells and the degradation of their metabolites. In our study, N-doped TiO2 (N-TiO2) was used to degrade C. raciborskii and the degradation was compared with that of the Microcystis aeruginosa (M. aeruginosa). Results showed that although the photodegradation of C. raciborskii was more difficult than that of M. aeruginosa, the treatment with N-TiO2 was still satisfactory. After adding 200 mg/L N-TiO2, C. raciborskii cells (5 (cid:1) 106 cells/mL) were completely destroyed within 20 h under visible light irradiation, and nearly 90% of the organic matter and CYN in the suspensions were also degraded, thereby markedly improving the water quality. The photocatalytic process starts with damage to the cell membrane resulting in the leakage of internal components. Subsequently, the leaked metabolites were oxidised by the reactive oxidizing species produced by N-TiO2. Thus, the application of N-TiO2 is a promising method for the treatment of C. raciborskii.
关键词： Microcystis aeruginosa,N-TiO2 photocatalysis,Cylindrospermopsin,Cylindrospermopsis raciborskii,Cell morphology
更新于2025-09-10 09:29:36
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Large-scale uniform fabrication and morphology control of ultrafine perovskite nanocrystals
摘要： Nanomaterials are playing more and more important roles in modern industry, while the large-scale fabrication and dispersibility still need to be addressed. This report explores the uniform fabrication and morphology control of ultrafine BaTiO3 (BT) nanocrystals using a "TEG-sol" method. By varying the reactant concentration, the obtained product sols, Ba/Ti ratios, structure and morphology of the nanocrystals are investigated. The results reveal that under low concentrations (0.4 - 0.8 mol/L), transparent sols with uniform BT nanocrystals are obtained. Increasing the concentration to higher than 1.0 mol/L, BT precipitates with abnormal large crystals are obtained. Moreover, the Ba/Ti ratio variation further reveals that the surface organics are critical to the control of crystal size and morphology. This investigation is potential to be extended to the synthesis of various perovskite nanocrystals.
关键词： morphology control,Nanomaterials,BaTiO3,TEG-sol method,perovskite nanocrystals
更新于2025-09-10 09:29:36
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Temperature-dependent distribution of silver nano particles on ferroelectric substrate: Molecular dynamics simulation
摘要： Silver nano particles have been widely used as catalyst for chemical industry. However, the catalytic efficiency of the silver has been limited by the aggregation of the silver, as the active sites are only located on the surface of the catalyst particles. In this paper we report the surface aggregation dynamics of silver on different ferroelectric polarization surface and temperature dependent behaviors. Meanwhile, reducing the particle size to obtain the dispersed morphology of silver was discussed by the dissipative particle dynamics method and density functional theory. The surface with upward polarization provides more electrons to the silver, which is responsible for the dispersed morphology of the silver.
关键词： Ferroelectrics,morphology,nano
更新于2025-09-10 09:29:36
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Crystal Morphology and Phase Transformation of LiAlO <sub/>2</sub> : Combined Experimental and First-Principles Studies
摘要： Layered α-LiAlO2 matrix often suffers from detrimental structural and morphological changes during its lifetime, especially under H2 containing fuel inlet environments of molten carbonate fuel cell systems. However, the underlying mechanism of this phase and morphological transformations has rarely been explored. In this study, transmission electron microscopy (TEM) techniques were used to determine the changes in structure and morphology of LiAlO2 samples lifted by a focused ion beam (FIB). In accordance with X-ray diffraction (XRD) analysis, TEM images show that under H-rich conditions the rhombohedral α-LiAlO2 transforms to tetragonal γ-LiAlO2 phase with the appearance of the (101) terminated octahedral shaped γ-LiAlO2 crystallites. We further support, and plausibly rationalize, the observed transformations using density functional theory (DFT) calculation. The DFT computed surface energies of γ-LiAlO2 reveal that the {101} surface becomes the lowest energy surface upon H-adsorption, thus leading to formation of observed octahedral geometry. Contrary to stabilization of γ-LiAlO2 surfaces upon H passivation, DFT revealed H-adsorption on α-LiAlO2 surfaces to be energetically unfavorable. This contrasting behavior of α-LiAlO2 and γ-LiAlO2 under H-rich environments could be a potential driving force for the observed α-LiAlO2 to γ-LiAlO2 phase transformation.
关键词： morphology,phase transformation,TEM,DFT,LiAlO2,XRD
更新于2025-09-10 09:29:36
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pH Variation as a Simple and Selective Pathway for Obtaining Nanoparticle or Nanocapsule Polysaccharides
摘要： The fabrication of polysaccharides to be nanoparticles or nanocapsules is quite specific due to various parameters and factors. The present work demonstrates a simple pathway to selectively prepare the ionic polysaccharide flakes to be nanoparticles or nanocapsules. The systematic studies on the model cases of cationic polysaccharide (i.e. chitosan) and anionic polysaccharide (i.e. alginate) confirm that pKa is the key point to tune the polysaccharides to be nanoparticles or nanocapsules. When the ionic polysaccharides were in an oil/water emulsion system, the pH close to pKa leads to the densely packed polysaccharide chains under the hydrogen bond networks, and as a result the crosslink occurs all through the chains to be nanoparticles. On the other hand, when pH was adjusted to the lower or higher than pKa depending on the types of ionic polysaccharide, the polysaccharide chains are under charge-charge repulsive force, resulting in the alignment of polysaccharide chains to be hollow nanospheres, and at that time the crosslink initiates the formation of nanocapsules. The present work, for the first time, clarifies that pH variation is the key to selectively prepare nanoparticles or nanocapsules, and this is important for delivery systems, coatings, sensors, etc.
关键词： pH-tunable morphology,chitosan,alginate,emulsion system,Polysaccharide
更新于2025-09-10 09:29:36
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[IEEE 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Shanghai (2018.8.8-2018.8.11)] 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Effect of Catalysts on Hydrothermal Preparation of boron nitride nanostructures
摘要： Boron nitride (BN) has attracted intense interests due to its excellent thermal conductivity and electrical insulation, which make it a promising thermal interface material for electronic packaging. Conventionally, the BN nanostructures were made from high cost method, e.g. chemical vapor deposition (CVD), which was restricted by the extremely high reaction temperature as well as the expensive instruments. Herein, a facile hydrothermal method was presented, where the catalysts were used to tune the phase and morphologies of the BN products starting from the boron and nitrogen sources. With different catalysts, the phase of the products could be changed from the orthorhombic to cubic BN, and the morphology underwent an evolution from nanorods to nanoflowers. The results are of great significance for the large-scale fabrication of BN nanostructures in a low cost.
关键词： Nanoflowers,Hydrothermal synthesis,Morphology evolution,Nanorods,Boron nitride,Catalyst
更新于2025-09-10 09:29:36
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[IEEE 2018 Open Innovations (OI) - South Africa (2018.10.3-2018.10.5)] 2018 Open Innovations Conference (OI) - Phase Formation Between Iridium Thin Films and Zirconium Carbide Prepared by Spark Plasma Sintering at Relatively Low Temperatures
摘要： Zirconium carbide (ZrC) samples were prepared by spark plasma sintering (SPS), at temperatures of 1700 °C, 1900 °C and 2100 °C at 50 MPa for 10 minutes. The phase and microstructure after the sintering process was investigated. The relative density of ZrC ceramic pellets formed at 1700 °C, 1900 °C and 2100 °C was measured and found to be 96.5 %, 98.9 % and 99.5 % respectively. The grain size of ZrC ceramic pellets was calculated and it was found to increase from 71.88 nm, 79.15 nm and 83.59 nm as the sintering temperature increased from 1700 oC, 1900 oC to 2100 oC respectively. The hardness of ZrC ceramic pellets was found to be 7.40 GPa, 17.00 GPa to 18.40 GPa at 1700 oC, 1900 oC to 2100 oC respectively. The preferred orientation at 1700 oC, 1900 oC and 2100 oC was the (200) plane. Iridium (Ir) thin films were deposited on ZrC ceramics by electron beam deposition method and annealed in vacuum at temperatures of 600 °C and 800 °C for 2h. The phase composition, solid-state reactions and surface morphology were investigated by grazing incidence x-ray diffraction (GIXRD), and scanning electron microscopy (SEM). XRD was used to identify the phases present in the as-deposited and annealed samples. XRD analysis showed that Ir2Zr was the initial phase formed at 600 °C. At temperature 800 °C, Ir reacted with the ZrC to form IrZr. The SEM images of as-sintered samples at 1700 oC, 1900 oC and 2100 oC showed that the ZrC surface was heterogeneous and uneven consisting of agglomerated granules with a few pores. The number of pores was observed to reduce with sintering temperature. After depositing Ir films on ZrC substrate, the structure of the Ir film followed that of the substrates. After annealing the Ir-ZrC samples at 600 oC and 800 oC, the further agglomeration of surface granules was observed.
关键词： morphology,interface reaction,Zirconium carbide,SPS,iridium
更新于2025-09-09 09:28:46
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[IEEE 2018 IEEE 3rd International Conference on Image, Vision and Computing (ICIVC) - Chongqing (2018.6.27-2018.6.29)] 2018 IEEE 3rd International Conference on Image, Vision and Computing (ICIVC) - Change Detection Based on the Combination of Improved SegNet Neural Network and Morphology
摘要： Through the analysis of satellite remote sensing image data, the identification of newly added buildings in the same area can be realized to judge the use of land. The identification of newly added buildings based on remote sensing images, involving image object extraction, semantic segmentation and change detection. The difficulty is not only to identify the changes of remote sensing images in different periods, but also to identify the newly added buildings with the original buildings. Both of the recognition effect and the detection precision of the traditional method based on mathematical modeling need to be improved. SegNet neural network is a kind of deep convolution neural network. It shows good performance in dealing with the task of semantic segmentation of single image, but it is directly applied to building change detection with low accuracy. The simulation results show that the improved SegNet neural network method improves the accuracy of the quantitative evaluation index F1 score by 8.6% compared with the conventional SegNet network in the newly added building detection effect in the same area in 2015 and 2017. In addition, the situation that the change detection result will produce a large number of noise, a combination of improved SegNet network and morphological method is adopted to eliminate the noise and reduce the misjudgment. The simulation results show that the F1 index increased further by 1.4% on the basis of 8.6%.
关键词： convolutional neural network,deep learning,remote sensing images,building change detection,morphology
更新于2025-09-09 09:28:46