Electron microscopy study of dense Si quantum wire arrays with presence of 2H hexagonal structure

2021 ◽  
Author(s):  
Weixi Wang ◽  
2002 ◽  
Vol 17 (6) ◽  
pp. 1287-1297 ◽  
Author(s):  
Zhengkui Xu ◽  
James L. Shull ◽  
Waltraud M. Kriven

Phase transformations in synthetic hexacelsian were investigated by hot-stage transmission electron microscopy. A second phase transformation from an orthorhombic to hexagonal structure was identified in the synthetic hexacelsian at approximately 700 °C. The hexacelsian was found to exhibit a sequence of phase transformations on heating of hexagonal (P63/mcm)–orthorhombic (Immm)–hexagonal (P6/mmm). Antiphase domain boundaries, which were observed in P63/mcm and Immm phases, were absent in the P6/mmm phase. Crystal symmetries of the three phases were determined by convergent beam electron diffraction, and space group symmetries were derived by comparison of experimental selected area electron diffraction patterns with computer-simulated patterns.


Author(s):  
Julie A. Martini ◽  
Robert H. Doremus

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.


Author(s):  
J.G. Wen ◽  
K.K. Fung

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.


2003 ◽  
Vol 112 ◽  
pp. 615-618 ◽  
Author(s):  
P. P. Rodriguez ◽  
J. San Jean ◽  
A. Iza-Mendia ◽  
V. Recarte ◽  
J. J. Pérez-Landazabal ◽  
...  

2008 ◽  
Vol 42 ◽  
pp. 14-22
Author(s):  
S. I. Genkal ◽  
V. G. Kharitonov

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).


2014 ◽  
Vol 48 ◽  
pp. 57-65 ◽  
Author(s):  
S. I. Genkal ◽  
M. I. Jarushina

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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