Nanocrystalline materials

To obtain a better understanding of the fatigue properties and crack growth characteristics of a nanocrystalline titanium based bulk metal glasses (Ti-BMG) made by vacuumed casting process, the fatigue failure mechanisms of Ti-BMG have been investigated via S e N and da/dN e DK tests.

7p viberbers 09-08-2023 8 3   Download

We report the effects of magnetic ordering on the temperature evolution of the Raman modes in nanocrystalline Dy3Fe5O12. The Dy3Fe5O12 was synthesized by an aqueous solegel method. X-ray diffraction, Raman spectroscopy and transmission electron microscopy studies revealed the phase purity and nanocrystalline nature.

7p viberbers 09-08-2023 6 3   Download

A Li-CuFe2O4 thin film has a well-defined nanocrystalline structure with a crystallite size of ~17 nm. The TEM and SEM images of the Li-CuFe2O4 thin film show a polyhedron shape of nanoparticles with uneven sizes, resulting in a significant change in its gas sensing characteristics such as sensitivity and sensor response.

6p viberbers 09-08-2023 5 3   Download

Results of this investigation have been correlated with the films structural and optical properties. Among the structural properties, surface roughness and morphology, and crystalline quality of the films have been obtained by using the XRD and AFM methods. Additionally, optical properties such as band gap tune-ability and dielectric constant have been determined by spectroscopic ellipsometer.

7p viberbers 09-08-2023 4 3   Download

Cadmium selenide (CdSe) thin films have been deposited on indium tin oxide coated glass substrate by simple electrodeposition method. X-ray Diffraction (XRD) studies identify that the as-deposited CdSe films are highly oriented to [002] direction and they belong to nanocrystalline hexagonal phase.

7p viberbers 09-08-2023 7 3   Download

Olive fiber is a sustainable material as well as alternative biomass for extraction of nanocrystalline cellulose (NCC), which has been widely applied in various industries. In the present study, ONC-I, ONC-II, and ONC-III were extracted from olive stem fiber at different hydrolysis reaction times of 30 min, 45 min, and 60 min, respectively.

7p viginny 30-12-2022 10 2   Download

Using a molecular dynamics (MD) model, we subject a nanocrystalline carbon steel work piece to grinding by hard alumina abrasives and study material removal and surface topography. A second, much larger MD model allows us to additionally study the microstructural and stress response of a polycrystalline ferritic work piece with a grain size that qualitatively reproduces macroscopic material behavior.

14p guernsey 28-12-2021 8 0   Download

A novel class of nanocrystalline/amorphous Gd3Ni/Gd65Ni35 composite microwires were created directly from melt-extraction through controlled solidification. X-ray diffraction (XRD), transmission electron microscopy (TEM), and selected area electron diffraction (SAED) confirmed the formation of a biphase nanocrystalline/amorphous structure in these wires.

8p meyerowitz 25-12-2021 6 0   Download

In this study, a preparation route of CoeCu alloys with soft magnetic properties by high-pressure torsion deformation is introduced. Nanocrystalline, supersaturated single-phase microstructures are obtained after deformation of CoeCu alloys, which are prepared from an initial powder mixture with Co-contents above 70 wt.%

9p meyerowitz 25-12-2021 10 0   Download

Artificially fabricated hydroxyapatite (HAP) shows excellent biocompatibility with various kinds of cells and tissues which makes it an ideal candidate for a bone substitute material. In this study, hydroxyapatite nanoparticles have been prepared by using the wet chemical precipitation method using calcium nitrate tetra-hydrate [Ca(NO3)2.4H2O] and di-ammonium hydrogen phosphate [(NH4)2HPO4] as precursors. The composite scaffolds have been prepared by a freeze-drying method with hydroxyapatite, chitosan, and gelatin which form a 3D network of interconnected pores.

17p tudichquannguyet 29-11-2021 11 1   Download

In the present study, we report on the synthesis of nanocrystalline phase pure ZnAl2O4 by a simple citrate solegel method. The materials annealed at different temperatures have been characterized for their structural and optical properties. The near infrared reflective properties of the samples are emphasized for use as solar reflective materials.

7p tamynhan4 06-09-2020 9 1   Download

To obtai n a bet ter und erstandi ng of the fatigue properties and crack growth characteristics of a nanocrystalline titan ium base d bulk metal glasses (Ti-BMG) mad e by vacu umed casting process, the fatigue failure mec hanism s of Ti-BMG have been investiga ted via S-N and da/dN-DK tests.

7p tamynhan4 06-09-2020 9 2   Download

In this study nanocomposite materials thin films based on poly [2-methoxy-5-(2’-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) and nanocrystalline TiO2 (nc-TiO2) have been fabricated. The photoluminescence (PL) spectra of pure MEH-PPV and nanohybrid films have shown that the excitation at a 377 nm wavelength leads to the strongly enhanced performance in photoluminescent intensity due to the compositions of TiO2 component.

6p nguyenxuankha_bevandan 14-08-2020 27 2   Download

In Design of high density transformers for high frequency high power converters, the abovementioned issues of high-frequency transformers are explored, particularly in regards to high-power converter applications. Loss calculations accommodating resonant operating waveform and Litz wire windings are explored. Leakage inductance modeling for large-number-of-stand Litz wire windings is proposed. The optimal design procedure based on the models is developed.

175p khoaicuto 19-03-2015 50 5   Download

Nanocrystalline materials have been the subject of widespread research over the past couple of decades with significant advancement in their understanding especially in the last few years [3]. As the name suggests, they are single or multi-phase polycrystals with nano scale (1 · 10
9 –250 · 10
9 m) grain size. At the upper limit of this regime, the term ‘‘ultra- fine grain size’’ is often used (grain sizes of 250–1000 nm).

38p loixinloi 08-05-2013 50 3   Download

The landmark paper by Gleiter [1] redirected a significant portion of the global research efforts in materials science. The importance of this paper can be gauged by its 1300+ cita- tions and the thousands of papers that appeared on this topic since its publication. Actually, this paper was preceded by an earlier, lesser known Gleiter paper, from 1983 [2]. In this paper, Gleiter points out the outstanding possibilities of what he called then ‘‘microcrystalline materials’’. The name ‘‘nanocrystalline’’ has since taken over.

86p loixinloi 08-05-2013 65 3   Download

A three gram oven-dried sample of holocellulose was placed in a 250 mL Erlenmeyer flask with a small watch glass cover. The flasks were placed into water bath that was maintained at 20 o C. The sample was then treated with 50 mL of 17.5 percent NaOH and thoroughly mixed for one minute. After the specimen was allowed to react with the solution for 29 minutes, 50 mL of distilled water was added and mixed well for another minute. The reaction continued for five more minutes. The contents of the flask were filtered by aid of...

130p loixinloi 08-05-2013 42 2   Download

In this paper, materials of ZnS:Cu, ZnS:Mn and ZnO:Co were prepared by ceramic method and co-precipitated method. The presence of transition metals such as Cu2+(3d9), Mn2+(3d5) in ZnS and Co2+(3d7) in ZnO make blue bands at around 476 nm, 486 nm and green band at around 514 nm disappeared. Simultaneously, there are luminescence bands at around 533 nm, 582 nm, 693 nm for bulk samples of ZnS:Cu, ZnS:Mn, ZnO:Co and 603 nm for nanocrystalline sample of ZnS:Mn.

7p tuanlocmuido 19-12-2012 59 3   Download

The process, as described in step (c) is repeated for a shorter time to expose the bottom silicon surface for further dry etching, as shown in Fig. 9(g). In order to expose sidewalls for the wet etch release, the structure is deepened using a similar multi-step dry etch process as described in step (d), except that low energy, high pressure isotropic dry etching is used instead of high energy, high pressure to preserve the less robust silicon dioxide that had taken the place of Cr as the etch mask. This deepening of the structure determines the gap between the...

6p quynho77 13-11-2012 53 4   Download

Cathodoluminescence (CL) is a non-destructive technique to characterize optical and electronic properties of nanostructures in many kinds of materials. Major subject is to investigate basic parameters in semiconductors, impurities in oxides and phase determination of minerals. CL is similar to photoluminescence (PL) technique, but the excitation by high energy electrons can produce all the transition to the higher energy excitation states and induce light emission in the wide energy range concerned with versatile types of electronic transitions in materials....

336p qsczaxewd 22-09-2012 36 3   Download