scholarly journals Mechanical adaptation of brachiopod shells via hydration-induced structural changes

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Johannes Ihli ◽  
Anna S. Schenk ◽  
Sabine Rosenfeldt ◽  
Klaus Wakonig ◽  
Mirko Holler ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Structural Changes ◽  
Molecular Level ◽  
Organic Matrix ◽  
Building Blocks ◽  
Hierarchical Organization ◽  
Mechanical Adaptation ◽  
X Ray ◽  
Structural Modifications ◽  
Complementary Set

AbstractThe function-optimized properties of biominerals arise from the hierarchical organization of primary building blocks. Alteration of properties in response to environmental stresses generally involves time-intensive processes of resorption and reprecipitation of mineral in the underlying organic scaffold. Here, we report that the load-bearing shells of the brachiopod Discinisca tenuis are an exception to this process. These shells can dynamically modulate their mechanical properties in response to a change in environment, switching from hard and stiff when dry to malleable when hydrated within minutes. Using ptychographic X-ray tomography, electron microscopy and spectroscopy, we describe their hierarchical structure and composition as a function of hydration to understand the structural motifs that generate this adaptability. Key is a complementary set of structural modifications, starting with the swelling of an organic matrix on the micron level via nanocrystal reorganization and ending in an intercalation process on the molecular level in response to hydration.

Multi-scale Investigation of Heterogeneous Swift Heavy Ion Tracks in Stannate Pyrochlore

2021 ◽  
Author(s):  
Eric O'Quinn ◽  
Cameron Tracy ◽  
William F. Cureton ◽  
Ritesh Sachan ◽  
Joerg C. Neuefeind ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Heavy Ion ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structural Modifications ◽  
Multi Scale ◽  
Ion Tracks ◽  
Swift Heavy Ion ◽  
Transmission Electron

Er2Sn2O7 pyrochlore was irradiated with swift heavy Au ions (2.2 GeV), and the induced structural modifications were systematically examined using complementary characterization techniques including transmission electron microscopy (TEM), X-ray diffraction...

Size dependent behavior of Fe3O4crystals during electrochemical (de)lithiation: an in situ X-ray diffraction, ex situ X-ray absorption spectroscopy, transmission electron microscopy and theoretical investigation

2017 ◽  
Vol 19 (31) ◽  
pp. 20867-20880 ◽  
Author(s):  
David C. Bock ◽  
Christopher J. Pelliccione ◽  
Wei Zhang ◽  
Janis Timoshenko ◽  
K. W. Knehr ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Structural Changes ◽  
Ex Situ ◽  
X Ray Diffraction ◽  
X Ray ◽  
Size Dependent ◽  
Transmission Electron ◽  
Dependent Behavior ◽  
X Ray Absorption

Crystal and atomic structural changes of Fe3O4upon electrochemical (de)lithiation were determined.

scholarly journals Structural Changes of Mo/ZSM-5 Catalysts During the Methane Dehydroaromatization

2009 ◽  
Vol 12 (1) ◽  
pp. 9 ◽  
Author(s):  
Z.R. Ismagilov ◽  
E.V. Matus ◽  
I.Z. Ismagilov ◽  
M.A. Kerzhentsev ◽  
V.I. Zailovskii ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Structural Changes ◽  
Atomic Ratio ◽  
X Ray ◽  
Reducing Atmosphere ◽  
Structure Changes ◽  
Transmission Electron ◽  
Methane Dehydroaromatization ◽  
Naoh Treatment ◽  
Mo Content

<p>The structure changes of Mo/ZSM-5 catalysts with different Mo content (2 and 10 wt. % Mo) and Si/Al atomic ratio (17, 30 and 45) during the methane dehydroaromatization have been investigated by X-ray powder diffractometry, N<sub>2</sub> adsorption and transmission electron microscopy. The treatment of Mo/ZSM-5 catalysts in reducing atmosphere (CH<sub>4</sub> or H<sub>2</sub>) at about 700 °C promotes development of mesoporous system. The pores are open to the exterior of the zeolite grain and have an entrance diameter of ~ 4-10 nm. It is proposed that mesopore formation in Mo/ZSM-5 catalyst is connected with the dealumination of zeolite. The mesopore formation in the parent H-ZSM-5 zeolite by NaOH treatment does not improve the activity of /ZSM-5 catalyst.</p>

A Study of Phase Reactions in a Complex 4.5 Al–3.5 Ti–Ni Base Alloy

1960 ◽  
Vol 4 ◽  
pp. 233-243
Author(s):  
John F. Radavich ◽  
W. J. Boesch
Keyword(s):  
Electron Microscopy ◽  
High Temperature ◽  
Structural Changes ◽  
Base Alloy ◽  
Phase Changes ◽  
X Ray Diffraction ◽  
High Temperature Alloy ◽  
X Ray ◽  
Nickel Base ◽  
Precipitated Phases

AbstractAn investigation of the phase changes in a complex aluminum-titanium-hardened nickel-base high-temperature alloy was carried out after solutioning at high temperatures and aging at lower temperatures. The physical distribution and size of the precipitated phases were studied by electron microscopy. X-ray diffraction and fluorescence analyses were carried out on chemically extracted residues. The results of the xtructure changes as well as correlation of some physical properties with the structural changes are presented.

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.

Controlled Synthesis of BaF2 Nanorods via Hydrothermal Microemulsion Method

2007 ◽  
Vol 121-123 ◽  
pp. 441-444
Author(s):  
Y.C. Chen ◽  
Y.G. Zhang
Keyword(s):  
Electron Microscopy ◽  
Raw Materials ◽  
Barium Chloride ◽  
Building Blocks ◽  
Controlled Synthesis ◽  
X Ray Diffraction ◽  
Microemulsion Method ◽  
X Ray ◽  
Transmission Electron ◽  
Microemulsion Droplet

BaF2 nanorods were synthesized by hydrothermal microemulsion method using sodium fluoride (NaF) and barium chloride (BaCl2) as the raw materials. The as-prepared products were characterized by powder X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The results showed that the products were composed of BaF2 nanorods with diameters of 18-62 nm and lengths up to 1μm. A directed aggregation growth process mediated by the microemulsion droplet building blocks is proposed for the formation of BaF2 nanorods. Further work is in progress to evaluate the possibility of synthesizing other fluoride 1D nanostructures using a similar method.

The structural changes of polycrystalline film C60/C70: Ni caused by Ni diffusion

1996 ◽  
Vol 11 (12) ◽  
pp. 3146-3151 ◽  
Author(s):  
E. Czerwosz ◽  
P. Byszewski ◽  
R. Diduszko ◽  
H. Wronka ◽  
P. Dluźewski ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Raman Spectroscopy ◽  
Structural Changes ◽  
Thermal Conditions ◽  
Vacuum Deposition ◽  
X Ray Diffraction ◽  
Polycrystalline Structure ◽  
X Ray ◽  
Transmission Electron

C60/C70: Ni films with 1.5 wt. % Ni concentration obtained by vacuum deposition under different thermal conditions have been investigated. The structural changes of the layers were investigated by transmission electron microscopy, electron and x-ray diffraction, and Raman spectroscopy. The polycrystalline structure was detected for the layers grown at approximately 450 K on the substrate. At elevated temperature and maintained temperature gradient on the substrate during the process, the changes of the layer's structure and the formation of Ni microcrystals were observed. The Ni microcrystals (5–10 nm in the diameter) and the elongated shapes dimensioned 10 × 150 nm were perceived.

Structural Modifications in Thin Films Caused by Gamma Radiation

2005 ◽  
Vol 480-481 ◽  
pp. 13-20 ◽  
Author(s):  
Khalil Arshak ◽  
Olga Korostynska ◽  
John Henry
Keyword(s):  
Thin Films ◽  
Gamma Radiation ◽  
Structural Changes ◽  
X Ray Diffraction ◽  
Thermal Vacuum ◽  
X Ray ◽  
Structural Modifications ◽  
Thin Oxide Films ◽  
Radiation Induced ◽  
Induced Changes

This paper reports on the gamma radiation-induced changes in thin oxide films deposited by thermal vacuum technique. Structures of various oxides thin films, such as In2O3, SiO and TeO2 and their mixtures in different proportions were studied. The influence of gamma radiation on In2O3/SiO films has resulted in significant changes in the microstructure of this film. Some kind of agglomerations with variable sizes in the range 0.5-3 µm has occurred. After a dose of 8160 µSv an evidence of partial crystallisation was observed with X-ray diffraction. Structural changes in TeO2 thin film were explored by means of Raman spectroscopy. After they have been exposed to g- radiation, a strong peak appeared at 448.83 cm-1, indicating further transformation to g-TeO2 modification.

Electroless Synthesis of 1.4 nm Pd and Pt Nanoparticles on Self-Assembled Rosette Nanotubes

2011 ◽  
Vol 1301 ◽  
Author(s):  
Rahul Chhabra ◽  
Hicham Fenniri
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Pt Nanoparticles ◽  
Hierarchical Organization ◽  
X Ray ◽  
Force Microscopy ◽  
Rosette Nanotubes ◽  
Atomic Force ◽  
Transmission Electron ◽  
Self Assembled

ABSTRACTElectroless synthesis and hierarchical organization of 1.4 nm Pd and Pt nanoparticles (NPs) on self-assembled Rosette Nanotubes (RNTs) is described. The nucleated NPs are nearly monodisperse and reveal supramolecular organizations guided by RNT templates. Interestingly, the narrow size distribution is attributable to unique templating behavior of RNTs. The resulting metal NP-RNT composites were characterized by Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). X-ray Photoelectron Spectroscopy (XPS) was also performed to confirm the nature and composition of RNT-templated NPs.

scholarly journals Nacre morphology and chemical composition in Atlantic winged oyster Pteria colymbus (Röding, 1798)

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11527
Author(s):  
Pablo Santana ◽  
Dalila Aldana Aranda
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Carbonate ◽  
Organic Matrix ◽  
Carbonyl Groups ◽  
X Ray Diffraction ◽  
Mineral Phase ◽  
X Ray ◽  
Minor Elements ◽  
Scanning Electron

The microstructure and nanostructure of nacre in Pteria colymbus were studied with high-resolution field emission scanning electron microscopy (FESEM). The tablets were found to be flat and polyhedral with four to eight sides, and lengths ranging from 0.6 to 3.0 µm. They consisted of nanocrystals 41 nm wide, growing in the same direction. X-ray diffraction showed the crystals to be mineral phase aragonite, which was confirmed by Raman spectroscopy. Fourier transform infrared spectroscopy identified a band at 1,786.95 cm−1 attributed to carboxylate (carbonyl) groups of the proteins present in the organic matrix as well as bands characteristic of calcium carbonate. X-ray fluorescence showed the nacre to contain 98% calcium carbonate, as well as minor elements (Si, Na, S and Sr) and trace elements (Mg, P, Cu, Al, Fe, Cl, K and Zn).

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