An Electron Microscopy Study of the Alkaline Hydrolysis Products of Tetraethoxysilane

1988 ◽  
Vol 121 ◽  
Author(s):  
Jeffrey Adams ◽  
Thomas Baird ◽  
Paul S. Braterman ◽  
James A. Cairns ◽  
David L. Segal
Keyword(s):  
Electron Microscopy ◽  
Water System ◽  
Ammonium Hydroxide ◽  
Microscopy Study ◽  
Particulate Material ◽  
Electron Microscopy Study ◽  
Optical Methods ◽  
Spherical Particles ◽  
Hydrolysis Products ◽  
Hydrolysis Of

ABSTRACTThe hydrolysis of tetraethoxysilane was studied in an ethanol-water system with ammonium hydroxide catalyst. Reactions were carried out with water concentrations of 5M and 10M and ammonia concentrations up to 1.7M, and the products examined by electron optical methods. Variation of reagent concentrations lead to changes in the product morphology from small irregular particles, through roughly spherical and spherical particles to large fused particles. Within the range of particulate material the variations in size can be related to the effect of reagent concentrations by consideration of the reactions occurring. The effect on morphology of replacing ammonia with ethylamine was investigated and resembles that of the use of much higher ammonia concentrations.

Electron Microscopy Study of Submicron Size Antiferromagnetic KMnF3 Nanoparticles and Their Self-assembly

2003 ◽  
Vol 775 ◽  
Author(s):  
Jeffrey Anderson ◽  
Rubi Garcia ◽  
Weilie L. Zhou
Keyword(s):  
Electron Microscopy ◽  
Self Assembly ◽  
Room Temperature ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Submicron Particles ◽  
Spherical Particles ◽  
Large Area ◽  
Homogeneous Crystal ◽  
Field Emission Electron Microscopy

AbstractSubmicron KMnF3 cubic and spherical nanoparticles were synthesized using the reverse micelle method. The nanostructures of the nanocrystals were studied by field emission electron microscopy and transmission electron microscopy. KMnF3 nanocrystals synthesized at room temperature started with cubic submicron particles (∼100 nm) and consisted of KMnF3 nanocrystallites (10-15 nm). As the reaction continued, the nanocrystals fused together and transformed into perfect cubic nanocrystals. Spherical beads composed of KMnF3 nanocrystallites were observed at low temperature synthesis. As the reaction continued, the spherical particles grew larger, however, no characteristic cubic shape of KMnF3 nanoparticles were observed. Even as they grew larger, there was no evidence of homogeneous crystal morphology as seen in the room temperature samples. Cubic shape KMnF3 nanocrystals were self-assembled into large area self-assembling patterns.

Factors influencing adhesive bonding at the bone/implant interface

1992 ◽  
Vol 50 (2) ◽  
pp. 1114-1115
Author(s):  
Julie A. Martini ◽  
Robert H. Doremus
Keyword(s):  
Electron Microscopy ◽  
Adhesive Bonding ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Bone Implant ◽  
Factors Influencing ◽  
Lr White ◽  
Transmission Electron ◽  
New Zealand White Rabbits ◽  
Scanning Electron

Tracy and Doremus have demonstrated chemical bonding between bone and hydroxylapatite with transmission electron microscopy. Now researchers ponder how to improve upon this bond in turn improving the life expectancy and biocompatibility of implantable orthopedic devices.This report focuses on a study of the- chemical influences on the interfacial integrity and strength. Pure hydroxylapatite (HAP), magnesium doped HAP, strontium doped HAP, bioglass and medical grade titanium cylinders were implanted into the tibial cortices of New Zealand white rabbits. After 12 weeks, the implants were retrieved for a scanning electron microscopy study coupled with energy dispersive spectroscopy.Following sacrifice and careful retrieval, the samples were dehydrated through a graduated series starting with 50% ethanol and continuing through 60, 70, 80, 90, 95, and 100% ethanol over a period of two days. The samples were embedded in LR White. Again a graduated series was used with solutions of 50, 75 and 100% LR White diluted in ethanol.

Transmission Electron Microscopy study of Bi-based superconducting phases

1990 ◽  
Vol 48 (4) ◽  
pp. 50-51
Author(s):  
J.G. Wen ◽  
K.K. Fung
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Single Crystals ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Space Groups ◽  
Superconducting Phases ◽  
Ceramic Samples ◽  
Transmission Electron ◽  
Modulated Structures

Bi-based superconducting phases have been found to be members of a structural series represented by Bi2Sr2Can−1Cun−1On+4, n=1,2,3, and are referred to as 2201, 2212, 2223 phases. All these phases are incommensurate modulated structures. The super space groups are P2/b, NBbmb 2201, 2212 phases respectively. Pb-doped ceramic samples and single crystals and Y-doped single crystals have been studied by transmission electron microscopy.Modulated structures of all Bi-based superconducting phases are in b-c plane, therefore, it is the best way to determine modulated structure and c parameter in diffraction pattern. FIG. 1,2,3 show diffraction patterns of three kinds of modulations in Pb-doped ceramic samples. Energy dispersive X-ray analysis (EDAX) confirms the presence of Pb in the three modulated structures. Parameters c are 3 0.06, 38.29, 30.24Å, ie 2212, 2223, 2212 phases for FIG. 1,2,3 respectively. Their average space groups are all Bbmb.

Electron microscopy study of microtexture in Cu-Al-Ni shape memory alloys processed by powder metallurgy

2003 ◽  
Vol 112 ◽  
pp. 615-618 ◽  
Author(s):  
P. P. Rodriguez ◽  
J. San Jean ◽  
A. Iza-Mendia ◽  
V. Recarte ◽  
J. J. Pérez-Landazabal ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Powder Metallurgy ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Microscopy Study ◽  
Electron Microscopy Study

On the morphology and taxonomy of Hannaea arcus (Bacillariophyta)

2008 ◽  
Vol 42 ◽  
pp. 14-22
Author(s):  
S. I. Genkal ◽  
V. G. Kharitonov
Keyword(s):  
Electron Microscopy ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Morphological Features ◽  
New Combination ◽  
Specific Rank ◽  
Ultraoligotrophic Lake ◽  
Emended Diagnosis

This electron microscopy study of the materials from ultraoligotrophic lake Elgygytgyn (Chukotka) revealed variability of morphological features in Hannaea arcus var. arcus and H. arcus var. recta. An emended diagnosis for H. arcus var. arcus is presented, and a new combination in specific rank is published: H. inaequidentata (Lagerstedt) Genkal et Kharitonov (= H. arcus var. recta).

To morphology, ecology and distribution of rare species Sellaphora hustedtii (Krasske) Lange-Bertalot et Werum (Bacillariophyta) from waterbodies of the Gydan Peninsula

2014 ◽  
Vol 48 ◽  
pp. 57-65 ◽  
Author(s):  
S. I. Genkal ◽  
M. I. Jarushina
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
River Basin ◽  
Rare Species ◽  
Western Siberia ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Diagnostic Features ◽  
Scanning Electron Microscopy Study ◽  
Scanning Electron

A rare species Sellaphora hustedtii, which is also new for the flora of Russia, has been found in waterbodies of the Messoyakha River basin (south-western part of the Gydan Peninsula, Western Siberia). The scanning electron microscopy study revealed variability of the main quantitative and qualitative diagnostic features of the species (length and width of the valve, number of striae and areolae in 10 μm, shape of the valve and structure of the raphe). New data on the ecology and distribution of the species allowed us to specify its diagnosis.

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