Formation and processing of mesoporous barium titanate powders via the micelle template method

2006 ◽  
Vol 21 (4) ◽  
pp. 941-946
Author(s):  
Hong-Wen Wang ◽  
Chien-Hung Kuo ◽  
Tsai-Huei Liao ◽  
Ren-Jay Lin ◽  
Syh-Yuh Cheng
Keyword(s):  
Electron Microscopy ◽  
Barium Titanate ◽  
Surface Area ◽  
Self Assembly ◽  
Structural Characteristics ◽  
Mesoporous Structure ◽  
Surface Areas ◽  
Transmission Electron ◽  
Organic Surfactant ◽  
Titanium Tetra Isopropoxide

Mesoporous barium titanate powders having a 100- to 300-nm size were prepared by hydration and condensation of titanium tetra-isopropoxide and barium precursors in the presence of an organic surfactant, tetradecylamine, which was used as a self-assembly micelle. The processing and sintering of these mesoporous barium titanate powders has been investigated. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy were used to identify the structural characteristics and morphologies of the powders. Mesoporous wormhole-like powders with surface areas around 53 ∼ 108 m2/g could be obtained after removing the micelle organics by calcination at 400 °C for 3 h. Powders derived using barium hydroxide were found to form a larger pore size and a higher surface area. The addition of acetic acid was also effective in increasing the surface area. A formation mechanism for the mesoporous structure is depicted. Heat treatment caused the mesoporous spheres to shrink, and 155- ∼ 330-nm grain sizes were readily obtained after pressureless sintering at 900 ∼ 1000 °C for 1 h in air.

scholarly journals Disappearance of macrophage surface folds after antibody-dependent phagocytosis.

1981 ◽  
Vol 89 (2) ◽  
pp. 223-229 ◽  
Author(s):  
H R Petty ◽  
D G Hafeman ◽  
H M McConnell
Keyword(s):  
Electron Microscopy ◽  
Cell Surface ◽  
Guinea Pig ◽  
Surface Area ◽  
Surface Membrane ◽  
Peritoneal Macrophages ◽  
Injection Technique ◽  
Surface Areas ◽  
Transmission Electron ◽  
Uptake Data

We have employed the method of Burwen and Satir (J. Cell Biol., 1977, 74:690) to measure the disappearance of surface folds from resident guinea pig peritoneal macrophages after antibody-dependent phagocytosis. Unilamellar phospholipid vesicles containing dimyristoylphosphatidylcholine and 1 mol % dinitrophenyl-epsilon-aminocaproyl-phosphatidylethanolamine, a lipid that possesses a hapten headgroup, were prepared by an ether injection technique. These vesicles were taken up by macrophages in a time- and temperature-dependent fashion. Vesicles that contained ferritin trapped in the internal aqueous volume were identified within macrophages by transmission electron microscopy. Scanning electron microscopy has shown that macrophage surface folds decrease dramatically after phagocytosis. The surface fold length (micrometer) per unit smooth sphere surface area (micrometer2) decreases from 1.3 +/- 0.3 micrometer-1 to 0.53 +/- 0.25 micrometer-1 when cells are incubated in the presence of specific anti-DNP antibody and vesicles at 37 degrees C. No significant effect was observed in the presence of antibody only or vesicles only. Our studies shown that phagocytosis is associated with a loss of cell surface folds and a loss of cell surface area, which is consonant with current views of the endocytic process. On the basis of our uptake data, we estimate that approximately 400 micrometer2 of vesicle surface membrane is internalized. The guinea pig macrophage plasma membrane has a total area of approximately 400 micrometer2 in control studies, whereas the cells have roughly 300 micrometer2 after phagocytosis. These estimates of surface areas include membrane ruffles and changes directly related to changes in cell volume. We suggest that during antibody-dependent phagocytosis a membrane reservoir is made available to the cell surface.

A High Resolution Study of G.P. Zones in Aluminum - 4.2 at % Silver

1982 ◽  
Vol 40 ◽  
pp. 722-723 ◽  
Author(s):  
R. Gronsky
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Computer Simulations ◽  
Structural Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Resolution Study

The phenomenon of clustering in Al-Ag alloys has been extensively studied since the early work of Guinierl, wherein the pre-precipitation state was characterized as an assembly of spherical, ordered, silver-rich G.P. zones. Subsequent x-ray and TEM investigations yielded results in general agreement with this model. However, serious discrepancies were later revealed by the detailed x-ray diffraction - based computer simulations of Gragg and Cohen, i.e., the silver-rich clusters were instead octahedral in shape and fully disordered, atleast below 170°C. The object of the present investigation is to examine directly the structural characteristics of G.P. zones in Al-Ag by high resolution transmission electron microscopy.

scholarly journals Alpha helical surfactant-like peptides self-assemble into pH-dependent nanostructures

Soft Matter ◽  
2021 ◽  
Vol 17 (11) ◽  
pp. 3096-3104
Author(s):  
Valeria Castelletto ◽  
Jani Seitsonen ◽  
Janne Ruokolainen ◽  
Ian W. Hamley
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Small Angle ◽  
Self Assembly ◽  
X Ray ◽  
Cryogenic Transmission Electron Microscopy ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Ph Dependent ◽  
Ray Scattering

A designed surfactant-like peptide is shown, using a combination of cryogenic-transmission electron microscopy and small-angle X-ray scattering, to have remarkable pH-dependent self-assembly properties.

Microstructure of LaB6-base thick film resistors

1992 ◽  
Vol 7 (8) ◽  
pp. 2225-2229 ◽  
Author(s):  
Z.G. Li ◽  
P.F. Carcia ◽  
P.C. Donohue
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Thick Film ◽  
Surface Area ◽  
Ion Milling ◽  
Cross Sectional ◽  
Electrically Conductive ◽  
Transmission Electron ◽  
High Temperature Processing ◽  
Thin Wedge

The microstructure of LaB6-base thick film resistors was investigated by cross-sectional transmission electron microscopy. The specimens were prepared by a technique that polished them to a thin wedge, thus avoiding ion-milling and permitting imaging over a distance of tens of microns. The resistor microstructure contained a finely divided electrically conductive phase of TaB2 and nonconducting crystals of CaTa4O11, formed during high temperature processing of glass and LaB6 ingredients of the thick film ink. Using higher surface area ingredients virtually suppressed the formation of CaTa4O11 crystals, and the microstructure became more uniform. Resistors made with higher surface area intermediates also had better voltage withstanding properties.

scholarly journals Impact of reaction vessel pressure on the synthesis of sliced activated carbon from date palm tree fronds

2015 ◽  
Vol 69 (5) ◽  
pp. 561-565 ◽  
Author(s):  
Muhammad Shoaib ◽  
Hassan Al-Swaidan
Keyword(s):  
Electron Microscopy ◽  
Flow Rate ◽  
Activated Carbons ◽  
Single Step ◽  
Reaction Vessel ◽  
Bet Surface Area ◽  
Palm Tree ◽  
Surface Areas ◽  
Transmission Electron ◽  
Co2 Flow

The effects of the reaction vessel pressure on the BET surface area, pore volume and pore size of the synthesis of sliced activated carbons (SAC) at 850?C starting from 0.10 to 0.40 bars were investigated. Other synthetic variables like dwell time, CO2 flow rate and heating ramp rate were kept constant during the whole study. Methodology involves a single step procedure using the mixture of gases (N2 and CO2). During activation flow rate of both gases are kept at 150 and 50ml/min respectively. The BET surface areas of the SAC prepared at 0.10, 0.15, 0.20, 0.25, 0.30, 0.35 and 0.40 bar after 30 minutes activation time are 666, 745, 895, 1094, 835, 658 and 625 m2/g, respectively. Scanning electron microscopy (SEM) for surface morphology, Energy dispersive spectroscopy (EDS), Transmission electron microscopy (TEM) for nano particle size were also carried out that also confirms the same trend.

scholarly journals Zig-zag Self-assembly of Magnetic Octahedral Fe3O4 Nanocrystals using in situ Liquid Transmission Electron Microscopy

2016 ◽  
Vol 22 (S5) ◽  
pp. 36-37
Author(s):  
Arnaud Demortiere ◽  
Charudatta Phatak ◽  
Andras Kovacs ◽  
Jan Caron ◽  
Nikita Repnin ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Self Assembly ◽  
Transmission Electron

Click Synthesis of Shape-Persistent Azodendrimers and their Orthogonal Self-Assembly to Nanofibres

2018 ◽  
Vol 71 (6) ◽  
pp. 463 ◽  
Author(s):  
Tamer El Malah ◽  
Hany F. Nour
Keyword(s):  
Electron Microscopy ◽  
Mass Spectrometry ◽  
Self Assembly ◽  
Molecular Structures ◽  
Side Chain ◽  
Spectroscopic Techniques ◽  
Molecular Weights ◽  
Transmission Electron ◽  
Click Synthesis ◽  
Scanning Electron

The copper(i)-catalyzed azide–alkyne cycloaddition (CuAAC) reaction has been efficiently utilized to synthesize a series of dendrons with amino functionalities. The aminodendrons successfully underwent azodimerization to furnish a series of pyridyl- and phenyl-based azodendrimers with peripheral alkyl or ether side chain substituents. The molecular structures of the azodendrimers were fully assigned using different spectroscopic techniques, such as 1H NMR and 13C NMR, and the molecular weights were determined using MALDI-TOF mass spectrometry. The molecular self-assembly of the azodendrimers was investigated by scanning electron microscopy and transmission electron microscopy, which revealed the formation of highly ordered and uniform self-assembled nanofibres.

scholarly journals Supercapacitor performance of porous nickel cobaltite nanosheets

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Xin Chen ◽  
Rui Xie ◽  
Hui Li ◽  
F. Jaber ◽  
F. Musharavati ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Solid State ◽  
Nickel Foam ◽  
Three Dimensional ◽  
High Specific Capacitance ◽  
Mesoporous Structure ◽  
Cobalt Hydroxide ◽  
Transmission Electron ◽  
Nickel Cobaltite ◽  
Electrode Capacitance

Abstract In this work, nickel cobaltite (NiCo2O4) nanosheets with a porous structure were fabricated on nickel foam as a working electrode for supercapacitor applications. The nanosheets were fabricated by electrochemical deposition of nickel–cobalt hydroxide on the nickel foam substrate at ambient temperature in a three-electrode cell followed by annealing at 300 °C to transform the coating into a porous NiCo2O4 nanosheet. Field emission scanning electron microscopy and transmission electron microscopy revealed a three-dimensional mesoporous structure, which facilitates ion transport and electronic conduction for fast redox reactions. For one cycle, the NiCo2O4 electrodeposited nickel foam has a high specific capacitance (1734.9 F g−1) at a current density (CD) of 2 A g−1. The electrode capacitance decreased by only approximately 12.7% after 3500 cycles at a CD of 30 A g−1. Moreover, a solid-state asymmetric supercapacitor (ASC) was built utilising the NiCo2O4 nanosheets, carbon nanotubes, and a polyvinyl alcohol-potassium hydroxide gel as the anode, cathode, and solid-state electrolyte, respectively. The ASC displayed great electrochemical properties with a 42.25 W h kg−1 energy density at a power density of 298.79 W kg−1.

scholarly journals Catalytic Dehydrogenation of Methylcyclohexane by Pt Nanoparticles Supported on Nitrogen doped Carbon

2020 ◽  
Vol 194 ◽  
pp. 01030
Author(s):  
Jian Wang ◽  
Shiguang Fan ◽  
Xuan Xu ◽  
Huiru Yun ◽  
He Liu ◽  
...  
Keyword(s):  
Surface Area ◽  
Pt Nanoparticles ◽  
Catalytic Performance ◽  
Support Surface ◽  
Catalytic Dehydrogenation ◽  
Nitrogen Doped ◽  
Surface Areas ◽  
Transmission Electron ◽  
Methylcyclohexane Dehydrogenation ◽  
Nitrogen Doped Carbon

Pt nanoparticles supported on nitrogen doped carbon (Pt/CN) catalysts with different surface areas were obtained and characterized by transmission electron microscope （TEM） and brunner-emmet-teller （BET）. The characterized results showed that Pt nanoparticles dispersed uniformly on the support surface, and the surface area of the Pt/CN catalyst increased with the increase of annealing temperature. Subsequently, the catalytic performance of Pt/CN catalysts for methylcyclohexane dehydrogenation was studied. The activity of Pt/CN catalysts in methylcyclohexane dehydrogenation increased with the increase of the surface area, Pt/CN-1000 catalyst has the largest surface area and the highest catalytic activity, with the methylcyclohexane conversion of 99% and the TOF value of 424.78 h-1 at 180 ℃ for 150 minutes.

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