scholarly journals The Transport System of Nacre Components through the Surface Membrane of Gastropods

2016 ◽  
Vol 672 ◽  
pp. 103-112 ◽  
Author(s):  
Elena Macías-Sánchez ◽  
Antonio G. Checa ◽  
Marc G. Willinger
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Calcium Carbonate ◽  
Lamellar Structure ◽  
Surface Membrane ◽  
Organic Matrix ◽  
X Ray ◽  
Transmission Electron ◽  
Means Of Transmission ◽  
Electron Energy Loss

The surface membrane is a lamellar structure exclusive of gastropods that is formed during the shell secretion. It protects the surface of the growing nacre and it is located between the mantle epithelium and the mineralization compartment. At the mantle side of the surface membrane numerous vesicles provide material, and at the nacre side, the interlamellar membranes detach from the whole structure. Components of nacre (glycoproteins, polysaccharides and calcium carbonate) cross the structure to reach the mineralization compartment, but the mechanism by which this occurs is still unknown. In this paper we have investigated the ultrastructure of the surface membrane and the associated vesicle layer by means of Transmission Electron Microscopy. Electron Energy Loss Spectroscopy and Energy-dispersive X-ray Spectroscopy were used for elemental analysis. The analyses revealed the concentration of calcium in the studied structures: vesicles, surface membrane, and interlamellar membranes. We discuss the possible linkage of calcium to the organic matrix.

Synthesis Second Assembly of Calcium Carbonate Sphere Chains

2010 ◽  
Vol 12 ◽  
pp. 115-122 ◽  
Author(s):  
Hong Zhen Xie ◽  
Xing Li
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Calcium Carbonate ◽  
Powder Diffraction ◽  
Building Block ◽  
Decomposition Temperature ◽  
X Ray ◽  
Thermogravimetry Analysis ◽  
Separate Spheres ◽  
Transmission Electron

Using simple and efficient celloidin membrane as basic template, and adding polyglycol reagent as assistant template, the calcium carbonate assembly sphere chains were synthesized. The length of chains was 6-8 µm, and the building block spheres were formed by nanoparticles with about 50 nm in diameter. All the products were characterized by transmission electron microscopy, X-ray powder diffraction, thermogravimetry analysis. The decomposition temperature increased by about 30 °C compared with the separate spheres, which may be caused by the bonding power of the spheres in chains. The products of calcium carbonate chains that kept in alcohol for 90d were found to have second-assembly to novel flower-like structures.

Fabrication of boron carbonitride (BCN) nanotubes and giant fullerene cages

2010 ◽  
Vol 88 (12) ◽  
pp. 1256-1261 ◽  
Author(s):  
Guifang Sun ◽  
Faming Gao ◽  
Li Hou
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
The Novel ◽  
X Ray Diffraction ◽  
Boron Carbonitride ◽  
X Ray ◽  
Transmission Electron ◽  
New Form ◽  
First Time ◽  
Electron Energy Loss

Boron carbonitride (BCN) nanotubes have been successfully prepared using NH4Cl, KBH4, and ZnBr2 as the reactants at 480 °C for 12 h by a new benzene-thermal approach in a N2 atmosphere. As its by-product, a new form of carbon regular hexagonal nanocages are observed. The samples are characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), transmission electron diffraction (TED), electron energy loss spectroscopy (EELS), and high-resolution transmission electron microscopy (HRTEM). The prepared nanotubes have uniform outer diameters in the range of 150 to 500 nm and a length of up to several micrometerss. The novel carbon hexagonal nanocages have a typical size ranging from 100 nm to 1.5 µm, which could be the giant fullerene cages of [Formula: see text] (N = 17∼148). So, high fullerenes are observed for the first time. The influences of reaction temperature and ZnBr2 on products and the formation mechanism of BCN nanotubes are discussed.

A study on the growth and structure of titania nanotubes

2004 ◽  
Vol 19 (2) ◽  
pp. 417-422 ◽  
Author(s):  
Wenzhong Wang ◽  
Oomman K. Varghese ◽  
Maggie Paulose ◽  
Craig A. Grimes ◽  
Qinglei Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chemical Process ◽  
Alkali Treatment ◽  
Titania Nanotubes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Spectroscopy Studies ◽  
Electron Energy Loss

Titania nanotubes synthesized by a soft chemical process are described, having diameters of 8 nm to 10 nm and lengths ranging from approximately 0.1 μm to 1 μm. X-ray diffraction studies show the structure of the as-prepared nanotubes is the same as that of the starting anatase TiO2nanoparticles. Energy-dispersive x-ray analysis and electron energy loss spectroscopy studies further indicate that the as-prepared nanotubes are composed of titania. Studies using transmission electron microscopy verified that the nanotubes are formed during alkali treatment, with subsequent acidic treatments having no effect on nanotube structure and shape.

TEM Observations of Precipitation of Coherent L12 and D022 Ordered Phases in Ni-V-Ge Alloys

2007 ◽  
Vol 561-565 ◽  
pp. 2365-2368 ◽  
Author(s):  
Yusuke Inuzuka ◽  
Shogo Ito ◽  
Takao Kozakai ◽  
Minoru Doi
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Transmission Electron Microscopy ◽  
Lamellar Structure ◽  
Supersaturated Solid Solution ◽  
Early Stage ◽  
Phase Separations ◽  
Transmission Electron ◽  
Ordered Phases ◽  
Means Of Transmission

Phase separations of A1 (γ) supersaturated solid solution into γ, cubic-L12 (γ') and tetragonal-D022 (γ") phases were investigated in Ni-V-Ge alloys by means of transmission electron microscopy (TEM). When Ni-15.8at%V-9.0at%Ge alloy is aged at 1073 K, at the early stage of ageing γ" phases are observed in the γ matrix as triangle- or diamond-shaped precipitates. With further ageing, colonies of lamellar structure consisting of two variants of γ" phase are dispersedly formed in the γ matrix and then γ" plates grow along the <110> direction. When Ni-14.5at%V-8.8.at%Ge alloy is isothermally annealed at 1023 K, first spherical γ' particles precipitate homogeneously in the γ matrix, followed by the formation of lamellar structure of γ" phases. In the course of further ageing, the lamellar structure develops, and only γ' particles around the lamellar structure grow and others gradually fade out.

scholarly journals Electrochemical Deposition and Formation Mechanism of Single-Crystalline Cu2O Octahedra on Aluminum

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Q. T. Du ◽  
J. S. Tan ◽  
Q. T. Wang ◽  
C. Y. Li ◽  
X. H. Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Formation Mechanism ◽  
Electrochemical Deposition ◽  
Cuprous Oxide ◽  
Edge Length ◽  
X Ray ◽  
Transmission Electron ◽  
Average Edge Length ◽  
Electron Energy Loss

A simple electrochemical deposition was developed to synthesize the cuprous oxide (Cu2O) octahedra on aluminum foils. The average edge length of the octahedra is about 300 nm. The chemical composition of the octahedra was determined using energy dispersive X-ray spectroscopy and electron energy-loss spectroscopy. The microstructure of the octahedra was investigated using transmission electron microscopy. The formation mechanism of the octahedra is proposed.

Electron Optical Characterization of Amorphous SIC:H CVD Films

1986 ◽  
Vol 69 ◽  
Author(s):  
R. M. Fisher ◽  
J. B. Posthill ◽  
M. Sarikaya ◽  
J. A. Reimer ◽  
M. Petrich
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Optical Characterization ◽  
Carbon Films ◽  
Optical Methods ◽  
X Ray ◽  
Silicon Carbon ◽  
Transmission Electron ◽  
Electron Energy Loss

AbstractThe utility of various electron optical methods to characterize the microstructure and composition of thin films of amorphous silicon-carbon films formed by plasma-activated CVD of SiH4 and CH4 has been investigated. The techniques employed include conventional and high resolution transmission electron microscopy and diffraction, non-dispersive x-ray spectroscopy and electron energy loss spectroscopy.

scholarly journals Получение аблированных частиц CeO-=SUB=-2-=/SUB=- с нанодисперсным распределением по составу

2020 ◽  
Vol 46 (20) ◽  
pp. 38
Author(s):  
М.А. Пугачевский ◽  
В.А. Мамонтов ◽  
Ней Вин Аунг ◽  
А.С. Чекаданов ◽  
А.П. Кузьменко
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Particle Size ◽  
Colloidal Solution ◽  
Vacancy Defects ◽  
X Ray ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Electron Energy Loss ◽  
Content Of Oxygen

A technique for the preparation of ablated particles of CeO2 of a nanosized composition has been developed. Using transmission electron microscopy and Small Angle X-ray Scattering, it has been found that the maximal particle size in a colloidal solution does not exceed 30 nm. According to Electron Energy Loss Spectroscopy, the content of oxygen vacancy defects increases with a decrease in the size of ablated nanoparticles.

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