CONTROLLED FABRICATION OF Nb2O5 HOLLOW NANOSPHERES AND NANOTUBES

2009 ◽  
Vol 23 (31n32) ◽  
pp. 3769-3775 ◽  
Author(s):  
FEI LIU ◽  
DONGFENG XUE
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Simple Procedure ◽  
Hollow Spheres ◽  
Reaction System ◽  
Inorganic Materials ◽  
Molar Ratio ◽  
Hollow Nanospheres ◽  
Simple Method ◽  
Wide Range

A simple procedure for one-step growing Nb 2 O 5 hollow nanospheres and nanotubes was proposed. The final products were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The as-obtained hollow spheres present a polycrystal surface while the nanotubes possess single crystal walls. Moreover, the factors that could impact the product morphology and crystal structure were discussed, and the corresponding mechanism was proposed accordingly. The crystal structure and morphology of products can be easily tuned by adjusting the molar ratio of Nb / Ti used, which determines the amount of F - ions existing in the reaction system. The as-obtained Nb 2 O 5 hollow nanospheres and nanotubes may exhibit enhanced applications in a wide range of areas. Additionally, it is rational to expect that this simple method can be extended to systems of other inorganic materials with desired morphologies.

scholarly journals Heterogeneous Catalytic Synthesis of 2-Methylbenzimidazole from 2-Nitroaniline and Ethanol Over Mg Modified Cu-Pd/γ-Al2O3

Catalysts ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 8 ◽  
Author(s):  
Feng Feng ◽  
Yaqin Deng ◽  
Zheng Cheng ◽  
Xiaoliang Xu ◽  
Qunfeng Zhang ◽  
...  
Keyword(s):  
Active Sites ◽  
Hydrogen Transfer ◽  
High Efficiency ◽  
Simple Procedure ◽  
Direct Synthesis ◽  
Reaction System ◽  
Simple Method ◽  
Heterogeneous Catalytic ◽  
Coupled Reaction ◽  
Al2o3 Catalyst

The direct synthesis of benzimidazoles from 2-nitroaniline and ethanol over Cu-Pd/γ-Al2O3 catalysts has the advantages of requiring easily available starting materials, having high efficiency, and a simple procedure. The modification by Mg of the Cu-Pd/γ-Al2O3 catalyst could improve the catalytic activity significantly. The addition of Mg to the Cu-Pd/γ-Al2O3 catalyst could maintain and promote the formation of CuPd alloy active sites. Meanwhile, the basicity of the support was enhanced appropriately by Mg, which generated more basic sites (Al-Oδ−) to accelerate the dehydrogenation of alcohol and increased the rate of the whole coupled reaction. The 2-nitroaniline was completely converted over Cu-Pd/(Mg)γ-Al2O3 after reacting for six hours, and the yield of 2-methylbenzimidazole was 98.8%. The results of this work provide a simple method to develop a more efficient catalyst for the “alcohol-dehydrogenation, hydrogen transfer and hydrogenation” coupled reaction system.

scholarly journals Electrospinning Synthesis and Photocatalytic Activity of Mesoporous TiO2Nanofibers

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Jing Li ◽  
Hui Qiao ◽  
Yuanzhi Du ◽  
Chen Chen ◽  
Xiaolin Li ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
High Photocatalytic Activity ◽  
Electrospinning Technique ◽  
Obvious Effect ◽  
Simple Method ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Excellent Photocatalytic Activity

Titanium dioxide (TiO2) nanofibers in the anatase structure were successfully prepared via electrospinning technique followed by calcination process. The morphologies, crystal structure, surface area, and the photocatalytic activity of resulting TiO2nanofibers were characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), nitrogen sorption, and UV-vis spectroscopy. The results revealed that calcination temperature had greatly influenced the morphologies of TiO2nanofibers, but no obvious effect was noticed on the crystal structure of TiO2nanofibers. The photocatalytic properties of TiO2nanofibers were evaluated by photocatalytic degradation of rhodamine B (RhB) in water under visible light irradiation. It was observed that TiO2nanofibers obtained by calcination at 500°C for 3 hours exhibited the most excellent photocatalytic activity. We present a novel and simple method to fabricate TiO2nanofibers with high-photocatalytic activity.

Investigation on Properties of Magnesia Grinding Wheels Used in Silicon Wafer Grinding

2014 ◽  
Vol 1017 ◽  
pp. 273-278
Author(s):  
Bing Jun Hao ◽  
Zhi Gang Dong ◽  
Shang Gao ◽  
Ren Ke Kang ◽  
Dong Ming Guo
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Integrated Assessment ◽  
Experimental Studies ◽  
Molar Ratio ◽  
Rockwell Hardness ◽  
Grinding Wheels ◽  
Curing Conditions ◽  
Molar Ratios ◽  
Scanning Electron

This paper presents the results of an experimental investigation on molar ratios of MgO/ MgCl2 affecting the hardness of magnesia grinding wheels, which is one of the most important properties. Magnesite grinding blocks of different ratios of MgO/MgCl2 were prepared. The surface Rockwell hardness of which was tested under the same curing conditions. By an integrated assessment of the experimental studies of hardness and component, it is recognized that the molar ratios of MgO/MgCl2 can significantly affect the properties of magnesia grinding wheels. With the increase of MgO/MgCl2 molar ratio, hardness of the specimens increases. Scanning electron microscopy (SEM) studies on grinding blocks of different ratios indicated that micro needle shaped crystal structure of phase 5 are mainly responsible for hardness development. Finally the optimal recipe was selected in consideration of the characteristics of the silicon mechanical chemical grinding (MCG), which was verified to be effective by the following grinding experiment.

Synthesis Behavior of La0.7Ca0.3MnO3 by Hydrothermal Method

2007 ◽  
Vol 26-28 ◽  
pp. 703-706
Author(s):  
Hung Su Im ◽  
Sang M. Lee ◽  
Chan Gyu Lee ◽  
Bon Heun Koo ◽  
Jung Bum Yoon ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Hydrothermal Reaction ◽  
Physical Property Measurement System ◽  
Physical Property ◽  
Transmission Electron ◽  
Wide Range ◽  
Property Measurement ◽  
Perovskite Type ◽  
Type Crystal

We indicated synthesization of LCMO by hydrothermal reaction. The results of transmission electron microscopy revealed that the LCMO particles had wide range in size and various in shapes. The LCMO particles had a perovskite-type crystal structure with some other phases. Magnetic property was measured by physical property measurement system. Their crystallinity and magnetization tended to increased with increasing reaction time.

A simple method for scanning electron microscopy of L-form colonies grown on agar

1971 ◽  
Vol 17 (6) ◽  
pp. 822-823 ◽  
Author(s):  
David J. Bibel ◽  
John W. Lawson
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Simple Procedure ◽  
Simple Method ◽  
Scanning Electron ◽  
Millipore Filters

A simple procedure, using Millipore filters, for the observation of L-form colonies of streptococci by scanning electron microscopy is described.

scholarly journals A simple pressure-assisted method for cryo-EM specimen preparation

2019 ◽  
Author(s):  
J. Zhao ◽  
H. Xu ◽  
M. Carroni ◽  
H. Lebrette ◽  
K. Wallden ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Pressure Gradient ◽  
Structural Biology ◽  
Specimen Preparation ◽  
Single Particles ◽  
Simple Method ◽  
Cryo Electron Microscopy ◽  
Low Concentrations ◽  
Wide Range ◽  
Major Bottleneck

AbstractCryo-electron microscopy (cryo-EM) has made great impacts on structural biology. However, specimen preparation remains a major bottleneck. Here, we report a simple method for preparing cryo-EM specimens, named Preassis, in which the excess liquid is removed by introducing a pressure gradient through the EM grid. We show the unique advantages of Preassis in handling samples with low concentrations of protein single particles and micro-crystals in a wide range of buffer conditions.

scholarly journals Synthesis of MIL-53(Fe) Metal-Organic Framework Material and Its Application as a Catalyst for Fenton-Type Oxidation of Organic Pollutants

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Pham Dinh Du ◽  
Pham Ngoc Hoai
Keyword(s):  
Electron Microscopy ◽  
Reaction Time ◽  
Photoelectron Spectroscopy ◽  
Metal Organic Framework ◽  
Reaction System ◽  
Molar Ratio ◽  
X Ray ◽  
Metal Organic ◽  
Adsorption Desorption ◽  
Organic Framework

The iron (III) benzene dicarboxylate metal-organic framework material (MIL-53(Fe)) was synthesized with either the solvent-thermal or hydrothermal method under different conditions. The influence of the type of solvents, molar ratio of precursors and solvent, temperature, and reaction time on the structure of MIL-53(Fe) was investigated. The material was characterized by using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), and N2 adsorption/desorption isotherm. The MIL-53(Fe) structure formed in N′, N-dimethylformamide (DMF) and methanol (MeOH) but not in water. In DMF, the molar ratio of precursors and solvent, temperature, and reaction time had a significant effect on the crystal structure of MIL-53(Fe). Under optimal conditions, MIL-53(Fe) has high crystallinity and a large specific surface area ( S BET  = 88.2 m2/g). The obtained MIL-53(Fe) could serve as a potential heterogeneous catalyst to oxidize phenol (PhN), rhodamine B (RhB), and methylene blue (MtB) in the Fenton-like reaction system at the different solution pHs.

A Simple Synthesis of Silver Nanoparticles in Laponite Suspensions

2007 ◽  
Vol 334-335 ◽  
pp. 813-816
Author(s):  
Yan Yang ◽  
Hai Tao Huang
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Heat Treatment ◽  
Silver Nanoparticles ◽  
Irradiation Time ◽  
Optical Absorption Spectra ◽  
Simple Method ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Additional Reduction

A simple method is described for preparing silver nanoparticles via photoreduction in layered laponite suspensions without any additional reduction agent or heat treatment. The properties of silver nanoparticles were studied as a function of the UV irradiation time. Transmission electron microscopy (TEM) was employed to study the variation of particle shape, size and size distribution. The crystal structure of silver nanoparticles was characterized powder Xray diffractometry (XRD). The optical absorption spectra of silver nanoparticles were obtained by ultraviolet-visible (UV-Vis) spectroscopy.

Phase Stability and Solidification Pathways in MoSi2 Based Alloys

1990 ◽  
Vol 213 ◽  
Author(s):  
P. S. Frankwicz ◽  
J. H. Perepezko
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Microstructural Evolution ◽  
Phase Stability ◽  
Dendritic Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wide Range ◽  
Metal Sublattice ◽  
Ternary Silicide

ABSTRACTThe phase equilibria developed upon substitution of Ti in MoSi2 along the pseudobinary MoSi2-TiSi2 section has been investigated using x-ray diffraction, and electron microscopy. The pseudobinary exhibits orthorhombic (C54), hexagonal (C40), and tetragonal (Cllb) crystalline structures. A hexagonal (C40) ternary silicide (Ti1-xMox)Si2 was observed to exhibit a relatively wide range of solubility with x in the range of 0.50 to 0.75, in contrast to MoSi2 which exhibits limited solubility for Ti. An analysis of the microstructural evolution following solidification reveals that the hexagonal β-(Ti,Mo)Si2 phase forms via a peritectic reaction between liquid and MoSi2 (Cllb). The primary dendritic structure during solidification in (Til-xMo2)Si2, where x z 0.80, has been determined to be tetragonal (Cllb) MoSi2. The results of this study confirm that substitutional alloying on the transition metal sublattice (Mo) is an effective approach to control of the phase stability and crystal structure in intersilicide reactions.

Recent Applications of High Resolution Electron Microscopy to Crystalline Arrays of Virus Particles

1978 ◽  
Vol 36 (3) ◽  
pp. 470-482 ◽  
Author(s):  
R.W. Horne
Keyword(s):  
Electron Microscopy ◽  
Image Processing ◽  
Analytical Techniques ◽  
Staining Technique ◽  
High Resolution Electron Microscopy ◽  
Optical Diffraction ◽  
Full Potential ◽  
Virus Particles ◽  
Resolution Electron ◽  
Wide Range

The technique of surrounding virus particles with a neutralised electron dense stain was described at the Fourth International Congress on Electron Microscopy, Berlin 1958 (see Home & Brenner, 1960, p. 625). For many years the negative staining technique in one form or another, has been applied to a wide range of biological materials. However, the full potential of the method has only recently been explored following the development and applications of optical diffraction and computer image analytical techniques to electron micrographs (cf. De Hosier & Klug, 1968; Markham 1968; Crowther et al., 1970; Home & Markham, 1973; Klug & Berger, 1974; Crowther & Klug, 1975). These image processing procedures have allowed a more precise and quantitative approach to be made concerning the interpretation, measurement and reconstruction of repeating features in certain biological systems.

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