scholarly journals Synchrotron x-ray microbeam diffraction from abalone shell

2004 ◽  
Vol 19 (5) ◽  
pp. 1471-1476 ◽  
Author(s):  
E. DiMasi ◽  
M. Sarikaya
Keyword(s):  
Self Assembly ◽  
Orientational Order ◽  
Amorphous Structure ◽  
Advanced Materials ◽  
Resolution Limit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Capillary Optics ◽  
Abalone Shell

Microstructured biomaterials such as mollusk shells receive much attention at present, due to the promise that advanced materials can be designed and synthesized with biomimetic techniques that take advantage of self-assembly and aqueous, ambient processing conditions. A satisfactory understanding of this process requires characterization of the microstructure not only in the mature biomaterial, but at the growth fronts where the control over crystal morphology and orientation is enacted. In this paper, we present synchrotron microbeam x-ray diffraction (XRD) and electron microscopy observations near the nacre–prismatic interface of red abalone shell. The relative orientations of calcite and aragonite grains exhibit some differences from the idealizations reported previously. Long calcite grains impinge the nacre–prismatic boundary at 45° angles, suggestive of nucleation on (104) planes followed by growth along the c axis. In the region within 100 μm of the boundary, calcite and aragonite crystals lose their bulk orientational order, but we found no evidence for qualitative changes in long-range order such as ideal powder texture or an amorphous structure factor. XRD rocking curves determined the mosaic of calcite crystals in the prismatic region to be no broader than the 0.3° resolution limit of the beamline’s capillary optics, comparable to what can be measured on geological calcite single crystals.

Preparation and Characterization of Polyaniline Nanotubes Doped with Different Acid

2013 ◽  
Vol 401-403 ◽  
pp. 663-666
Author(s):  
Xue Lian Bai ◽  
Jian Ting Mei ◽  
Zhong Guo Mu ◽  
Yun Bai
Keyword(s):  
Acetic Acid ◽  
Self Assembly ◽  
Ammonium Persulfate ◽  
Tetraacetic Acid ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure And Property ◽  
Assembly Method ◽  
Polyaniline Nanotubes

Polyaniline (PANI) nanotubes were synthesized separately using amino acetic acid (AA), ethylenediamine tetraacetic acid (EDTA), oxalic acid (OA) as dopant and ammonium persulfate (APS) as oxidant by a self-assembly method. SEM, TEM,FTIR and X-ray diffraction (XRD) and applying the 4 probes method characterized the morphology, structure and property of the product. It was found that nanotubes morphology were synthesized when the [Aci/[A ratio is 1:2.The room template conductivity of the products were studied.

Synthesis and Characterization of Polyaniline Nanotubes Doped with Amino Acetic Acid

2012 ◽  
Vol 184-185 ◽  
pp. 1285-1288 ◽  
Author(s):  
Xue Lian Bai ◽  
Jian Ting Mei ◽  
Yun Bai ◽  
Zhong Guo Mu
Keyword(s):  
Acetic Acid ◽  
Self Assembly ◽  
Ammonium Persulfate ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure And Property ◽  
Assembly Method ◽  
Doped Polyaniline

Doped polyaniline (PANI) nanostructure has been prepared at room temperature using amino acetic acid (AA) as dopant and ammonium persulfate (APS) as oxidant by a self-assembly method. The structure and property of polyaniline nanostructure were characterized by SEM, TEM，IR and X-ray diffraction (XRD) and applying the 4 probes method. The results showed the production was PANI. The effect of molar ratio of AA to An affected the morphology of the product and room template conductivity of the products were studied.

Fabrication and Characterization of Nanoscale Porous Copper Film

2012 ◽  
Vol 433-440 ◽  
pp. 683-688
Author(s):  
Liu Wei Ding ◽  
Hao Ran Geng ◽  
Jing Hua Xu
Keyword(s):  
Copper Film ◽  
Selective Dissolution ◽  
Amorphous Structure ◽  
Nanometer Scale ◽  
Copper Films ◽  
Nanocrystalline Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Porous Copper

Cu-38Zn thin film (wt %) was deposited on the unheated microscope glass at the nanometer scale by DC magnetron sputtering. Subsequently, the nanocrystalline films were dealloyed in H2SO4 aqueous solution etching of zinc component, resulting in the formation of nanoscale porous copper film with average porous diameter of approximately 94 nm. The films microstructure and element composition were characterized by X-ray diffraction and scanning electron microscopy. The experimental results show that Cu-38Zn films are quasi-amorphous structure, porous copper film with different porous sizes is prepared by selective dissolution of zinc atoms from a nanocrystalline dual-phase film under free corrosion conditions, the grain size of the Cu-Zn films has an important effect on the dealloying process and the microstructures of the nanoscale copper films.

Mechanical Spectroscopy Study on Cu53.5Zr42Al4.5 Alloy

2011 ◽  
Vol 312-315 ◽  
pp. 1233-1237
Author(s):  
Odila Florêncio ◽  
Paulo Sergio Silva ◽  
Fernando Henrique De Sá ◽  
Paulo Wilmar Barbosa Marques ◽  
Javier Andres Muñoz Chaves ◽  
...  
Keyword(s):  
Internal Friction ◽  
Amorphous Structure ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
Mechanical Spectroscopy ◽  
Temperature Function ◽  
X Ray ◽  
Casting Technique ◽  
Dsc Curves

This study consists of the characterization of the anelastic properties of a Bulk Metallic Glasses (BMG) by mechanical spectroscopy, which can be defined as an energy absorption technique. The equipment used was the acoustic elastometer system, the anelastic relaxation spectra were carried out with a heating rate of 1 K/min and vacuum better than 10-5 torr, in the temperature range of 300 K to 640 K. The amorphous sample studied, with nominal composition of Cu53.5Zr42Al4.5, was processed by skull push-pull casting technique in a rectangular cavity cooper mould. Differential scanning calorimeter (DSC) curves have evidenced the amorphous structure although the X-ray diffraction (XDR) pattern has indicated a heterogeneous microstructure with amorphous matrix and some metaestable nanocrystalline phases which have not been identified yet. The dynamical elastic modulus of this alloy (between 54 GPa and 58 GPa at room temperature) and internal friction patterns as temperature function implied an increase of the crystalline phase during the measurements. This effect was confirmed with new X-ray diffraction measurements after the internal friction experiments.

Synthesis and Characterization of Quaternary Ti-Si-C-N Film Deposited by Middle Frequency Magnetron Sputtering

2012 ◽  
Vol 581-582 ◽  
pp. 540-543
Author(s):  
Jin Long Jiang ◽  
Di Chen ◽  
Wei Jun Zhu
Keyword(s):  
Magnetron Sputtering ◽  
Elastic Recovery ◽  
Amorphous Structure ◽  
Columnar Structure ◽  
Maximum Hardness ◽  
X Ray Diffraction ◽  
X Ray ◽  
Large Particles ◽  
Si Wafer

Quaternary Ti-Si-C-N films were deposited Si wafer by middle frequency magnetron sputtering Ti80Si20 twin-targets in mixture atmosphere of Ar, CH4 and N2. Scanning electron microscopy (SEM) and x-ray diffraction (XRD) results indicate that the films present an amorphous structure with no columnar structure. These films are quite uniform and dense without large particles. The film deposited at 10 sccm CH4 and 10 sccm N2 flow rates exhibits a maximum hardness of 18.9 GPa and high elastic recovery of 97%.

scholarly journals Characterization of Archaeological European White Elm (Ulmus laevis P.) and Black Poplar (Populus nigra L.)

Forests ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1329
Author(s):  
Amir Ghavidel ◽  
Reza Hosseinpourpia ◽  
Holger Militz ◽  
Viorica Vasilache ◽  
Ion Sandu
Keyword(s):  
Photoelectron Spectroscopy ◽  
Amorphous Structure ◽  
Sorption Behavior ◽  
Vapor Sorption ◽  
X Ray Diffraction ◽  
Dynamic Vapor Sorption ◽  
X Ray ◽  
Archaeological Wood ◽  
Extensive Degradation

The present study aims at characterization of freshly-cut and archaeological European white elm and poplar. The archaeological elm sample was buried at a depth of 8–10 m inside of soil with age approximation of ~1800–2000 years old, and the archaeological poplar sample was a part of a boat in a freshwater lake or river with age estimation of ~1000–1200 years. Alteration in the chemical structure of the elm and poplar samples due to the ageing process were confirmed by X-ray photoelectron spectroscopy (XPS). Both archaeological wood (AW) samples illustrated considerably lower cellulose crystallinity than the fresh samples as determined by X-ray diffraction. The sorption behavior of AW and fresh wood (FW) samples were evaluated by means of dynamic vapor sorption (DVS) analysis. Results exhibited a higher equilibrium moisture content (EMC) and sorption hysteresis values in archaeological elm and poplar as compared with the fresh samples. Higher hydrophilicity of the AW samples than the FW ones is attributed to their higher amorphous structure. The extensive degradation of AW samples were also confirmed by scanning electron microscopy (SEM) micrographs.

Preparation and Characterization of MoS2 Microsphere by Hydrothermal Method

2013 ◽  
Vol 631-632 ◽  
pp. 306-309 ◽  
Author(s):  
Ya Ru Cui ◽  
Jiang Shan He ◽  
Xiao Ming Li ◽  
Jun Xue Zhao ◽  
Ao Li Chen ◽  
...  
Keyword(s):  
Self Assembly ◽  
Hydrothermal Reaction ◽  
Average Diameter ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Ammonium Heptamolybdate ◽  
X Ray ◽  
Influence Mechanism ◽  
Dispersing Agent

In this work, MoS2 microsphere was synthesized by hydrothermal reaction, in which thiourea (CS(NH2)2) was used as S-source and reducing agent, ammonium heptamolybdate ((NH4)6Mo7O24.4H2O) was used as Mo-source. The influence of temperature, as well as different dispersing agents, on the reaction product’s morphology, structure and phase composition was discussed. X-ray diffraction results show that all the as-synthesized products are the hexagonal 2H-MoS2 without impurity. SEM images of the as-prepared MoS2 samples without adding any dispersing agent present spherical morphology with sheet-like structures shaped on the surface. A possible formation mechanism of the MoS2 microsphere is that of self-assembly growth process; In addition, for the samples adding surfactant CTAB, SDBS or PVP in the reactants, the MoS2 is confined to layered structure. Compared with SDBS and PVP, CTAB has the best dispersion effect which ensure the as-synthesized microsphere with about 300nm average diameter, and the influence mechanism of which can be deduced as electrostatic interaction and stereo-hindrance effect.

Characterization of Glass Forming Alloy Fe43.2Co28.8B19.2Si4.8Nb4 Processed by Spray Forming and Wedge Mold Casting Techniques

2011 ◽  
Vol 691 ◽  
pp. 23-26 ◽  
Author(s):  
C. Triveño Rios ◽  
Conrado R. M. Afonso ◽  
Claudemiro Bolfarini ◽  
Walter José Botta Filho ◽  
Claudio Shyinti Kiminami
Keyword(s):  
Amorphous Structure ◽  
Spray Forming ◽  
Bulk Glass ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Glass Forming ◽  
Glassy Alloys ◽  
Mold Casting

Bulk glassy alloys based on the Fe-Co-B-Si-Nb system have already achieved high levels of mechanical strength. The present work investigated the microstructural evolution of Fe43.2Co28.8B19.2Si4.8Nb4 alloy during the spray forming and wedge mold casting processes, with emphasis on the formation of amorphous phase. The microstructure was evaluated by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). The region outer the spray deposit showed the formation of an amorphous structure with a thickness of ~2.5 mm, while that of the wedge-shaped sample exhibited a thickness of up to ~1.5 mm, suggesting that both processes show a promising potential for the production of bulk glass alloys.

Microscopical Study of Au Nanocrystals Self-Assembled on (100)Si and SiO2/(100)Si Substrates

2006 ◽  
Vol 959 ◽  
Author(s):  
Emanuela Piscopiello ◽  
Leander Tapfer ◽  
Marco Vittori Antisari ◽  
Pasquale Paiano ◽  
Paola Prete ◽  
...  
Keyword(s):  
Self Assembly ◽  
Au Nanoparticles ◽  
Microscopical Study ◽  
X Ray Diffraction ◽  
X Ray ◽  
Si Substrates ◽  
Au Film ◽  
Assembly Method ◽  
Transmission Electron

ABSTRACTThis work reports on the structural characterization of Au nanocrystals directly prepared on the surface of (100)Si and 150 nm-thick SiO2 deposited (100)Si substrates, by a physical self-assembly method, consisting in the UHV evaporation of a thin Au film and its successive high temperature annealing. The morphology, orientation, and crystalline structure of Au nanocrystals were characterized by scanning and high-resolution transmission electron microscopy and X-ray diffraction, respectively. Experimental results show that the nature of the substrate strongly influences the process of Au nanocrystal formation upon heat treatment, by affecting the interaction of deposited Au with the underlying material. In the case of clean (100)Si substrates the Au strongly interacts with Si, so that Au nanoislands are obtained with a well defined epitaxial relationships with the substrate, i.e. [100]AuÐÐ[110]Si and [110]AuÐÐ[311]Si. The nanoisland shape is affected by faceting at the Au/Si interface, the Au nanocrystal being limited by the {111}, {311}, {711} and {-111} planes of Si. In the case of SiO2/(100)Si substrates spherical shaped Au nanoparticles with random crystal orientation are instead, produced.

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