scholarly journals Microstructure and Fluctuation-Induced Conductivity Analysis of Bi2Sr2CaCu2O8+δ (Bi-2212) Nanowire Fabrics

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 986
Author(s):  
Michael Rudolf Koblischka ◽  
Anjela Koblischka-Veneva ◽  
XianLin Zeng ◽  
Essia Hannachi ◽  
Yassine Slimani
Keyword(s):  
Three Dimensional ◽  
Short Wave ◽  
Superconducting Transition ◽  
Fiber Mats ◽  
Nanowire Network ◽  
Fluctuation Induced Conductivity ◽  
The Individual ◽  
Nanofiber Mats ◽  
Nanowire Networks ◽  
First Time

Resistance measurements were performed on Bi2Sr2CaCu2O8+δ (Bi-2212) fabric-like nanowire networks or nanofiber mats in the temperature interval 3 K ≤T≤ 300 K. The nanowire fabrics were prepared by means of electrospinning, and consist of long (up to 100 μm) individual nanowires with a mean diameter of 250 nm. The microstructure of the nanowire network fiber mats and of the individual nanowires was thoroughly characterized by electron microscopy showing that the nanowires can be as thin as a single Bi-2212 grain. The polycrystalline nanowires are found to have a texture in the direction of the original polymer nanowire. The overall structure of the nanofiber mats is characterized by numerous interconnects among the nanowires, which enable current flow across the whole sample. The fluctuation-induced conductivity (excess conductivity) above the superconducting transition temperature, Tc, was analyzed using the Aslamzov-Larkin model. Four distinct fluctuation regimes (short-wave, two-dimensional, three-dimensional and critical fluctuation regimes) could be identified in the Bi-2212 nanowire fabric samples. These regimes in such nanowire network samples are discussed in detail for the first time. Based on this analysis, we determine several superconducting parameters from the resistance data.

scholarly journals Giant Magnetoresistance and Magneto-Thermopower in 3D Interconnected NixFe1−x/Cu Multilayered Nanowire Networks

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1133
Author(s):  
Nicolas Marchal ◽  
Tristan da Câmara Santa Clara Gomes ◽  
Flavio Abreu Araujo ◽  
Luc Piraux
Keyword(s):  
Giant Magnetoresistance ◽  
Nanowire Array ◽  
Three Dimensional ◽  
Strong Increase ◽  
Thermoelectric Effect ◽  
Heat Management ◽  
Thermoelectric Effects ◽  
Nanowire Network ◽  
Potential Applications ◽  
Nanowire Networks

The versatility of the template-assisted electrodeposition technique to fabricate complex three-dimensional networks made of interconnected nanowires allows one to easily stack ferromagnetic and non-magnetic metallic layers along the nanowire axis. This leads to the fabrication of unique multilayered nanowire network films showing giant magnetoresistance effect in the current-perpendicular-to-plane configuration that can be reliably measured along the macroscopic in-plane direction of the films. Moreover, the system also enables reliable measurements of the analogous magneto-thermoelectric properties of the multilayered nanowire networks. Here, three-dimensional interconnected NixFe1−x/Cu multilayered nanowire networks (with 0.60≤x≤0.97) are fabricated and characterized, leading to large magnetoresistance and magneto-thermopower ratios up to 17% and −25% in Ni80Fe20/Cu, respectively. A strong contrast is observed between the amplitudes of magnetoresistance and magneto-thermoelectric effects depending on the Ni content of the NiFe alloys. In particular, for the highest Ni concentrations, a strong increase in the magneto-thermoelectric effect is observed, more than a factor of 7 larger than the magnetoresistive effect for Ni97Fe3/Cu multilayers. This sharp increase is mainly due to an increase in the spin-dependent Seebeck coefficient from −7 µV/K for the Ni60Fe40/Cu and Ni70Fe30/Cu nanowire arrays to −21 µV/K for the Ni97Fe3/Cu nanowire array. The enhancement of the magneto-thermoelectric effect for multilayered nanowire networks based on dilute Ni alloys is promising for obtaining a flexible magnetic switch for thermoelectric generation for potential applications in heat management or logic devices using thermal energy.

scholarly journals Fabrication and Characterization of Lignin/Dendrimer Electrospun Blended Fiber Mats

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 518
Author(s):  
Somaye Akbari ◽  
Addie Bahi ◽  
Ali Farahani ◽  
Abbas S. Milani ◽  
Frank Ko
Keyword(s):  
Thermal Characteristics ◽  
Dendritic Polymers ◽  
Amino Groups ◽  
Fiber Mats ◽  
Potential Applications ◽  
Solution Electrospinning ◽  
Nanofiber Mats ◽  
Softwood Kraft Lignin ◽  
First Time

Blending lignin as the second most abundant polymer in Nature with nanostructured compounds such as dendritic polymers can not only add value to lignin, but also increase its application in various fields. In this study, softwood Kraft lignin/polyamidoamine dendritic polymer (PAMAM) blends were fabricated by the solution electrospinning to produce bead-free nanofiber mats for the first time. The mats were characterized through scanning electron microscopy, Fourier transform infrared (FTIR) spectroscopy, zeta potential, and thermogravimetry analyses. The chemical intermolecular interactions between the lignin functional groups and abundant amino groups in the PAMAM were verified by FTIR and viscosity measurements. These interactions proved to enhance the mechanical and thermal characteristics of the lignin/PAMAM mats, suggesting their potential applications e.g. in membranes, filtration, controlled release drug delivery, among others.

scholarly journals Excess Conductivity Analysis of Polycrystalline FeSe Samples with the Addition of Ag

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5018
Author(s):  
Michael Rudolf Koblischka ◽  
Yassine Slimani ◽  
Anjela Koblischka-Veneva ◽  
Thomas Karwoth ◽  
XianLin Zeng ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Superconducting Transition ◽  
Zero Temperature ◽  
Doping Amount ◽  
One Dimensional ◽  
Critical Magnetic Fields ◽  
Excess Conductivity Analysis ◽  
Fluctuation Induced Conductivity ◽  
Critical Current Density Jc ◽  
Fese Superconductors

Bulk FeSe superconductors of the iron-based (IBS) “11” family containing various additions of silver were thoroughly investigated concerning the microstructure using optical microscopy and electron microscopy (TEM and SEM). The measurements of electrical resistivity were performed through the four-point technique in the temperature interval T= 2–150 K. The Aslamazov–Larkin model was employed to analyze the fluctuation-induced conductivity (FIC) in all acquired measurements. In all studied products, we found that the FIC curves consist of five different regimes of fluctuation, viz. critical region (CR), three-dimensional (3D), two-dimensional (2D), one-dimensional (1D), and shortwave fluctuation (SWF) regimes. The critical current density (Jc), the lower and upper critical magnetic fields (Bc1 and Bc2), the coherence length along the c-axis at zero-temperature (ξc(0)), and further parameters were assessed with regards to the silver amount within the products. The analyses discloses a diminution in the resistivity and a great reduction in ξc(0) with Ag addition. The optimal silver doping amount is achieved for 7 wt.%, which yields the best superconducting transition and the greatest Jc value.

Surface Photovoltage Study of Indium Phosphide Nanowire Networks

2011 ◽  
Vol 1350 ◽  
Author(s):  
Andrew J. Lohn ◽  
Jin-Woo Han ◽  
Nobuhiko P. Kobayashi
Keyword(s):  
Thin Film ◽  
Indium Phosphide ◽  
Numerical Solutions ◽  
Three Dimensional ◽  
Transport Equations ◽  
Surface Photovoltage ◽  
Nanowire Network ◽  
Nanowire Networks

ABSTRACTSurface photovoltage of three-dimensional networks composed of fused indium phosphide (InP) nanowires is discussed. Particular emphasis is given to the dependence of surface photovoltage on the chopping frequency of light that excites the nanowire network as observed in regions which are laterally separated from the excitation. The nanowire network is modeled as a thin film to simplify numerical solutions to transport equations which aids in the interpretation of diffusion and drift of photo-generated carriers within the nanowire network.

scholarly journals ZnO Nanowire Networks as Photoanode Model Systems for Photoelectrochemical Applications

Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 693 ◽  
Author(s):  
Liana Movsesyan ◽  
Albert Maijenburg ◽  
Noel Goethals ◽  
Wilfried Sigle ◽  
Anne Spende ◽  
...  
Keyword(s):  
Anatase Phase ◽  
Three Dimensional ◽  
Atomic Layer ◽  
Model Systems ◽  
Zno Nanowire ◽  
Chemical Corrosion ◽  
Tio2 Nanowire ◽  
Nanowire Network ◽  
Nanowire Networks ◽  
3D Networks

In this work, the fabrication of zinc oxide (ZnO) nanowire networks is presented. By combining ion-track technology, electrochemical deposition, and atomic layer deposition, hierarchical and self-supporting three-dimensional (3D) networks of pure ZnO- and TiO2-coated ZnO nanowires were synthesized. Analysis by means of high-resolution transmission electron microscopy revealed a highly crystalline structure of the electrodeposited ZnO wires and the anatase phase of the TiO2 coating. In photoelectrochemical measurements, the ZnO and ZnO/TiO2 nanowire networks, used as anodes, generated higher photocurrents compared to those produced by their film counterparts. The ZnO/TiO2 nanowire network exhibited the highest photocurrents. However, the protection by the TiO2 coatings against chemical corrosion still needs improvement. The one-dimensionality of the nanowires and the large electrolyte-accessible area make these 3D networks promising photoelectrodes, due to the improved transport properties of photogenerated charge carriers and faster redox reactions at the surface. Moreover, they can find further applications in e.g., sensing, catalytical, and piezoelectric devices.

scholarly journals La torre nella torre. Recupero e rilievo 3D per la fruizione della Torre Matta ad Otranto

X ◽  
2020 ◽  
Author(s):  
Giovanna Muscatello
Keyword(s):  
Fifteenth Century ◽  
Three Dimensional ◽  
Three Dimensional Model ◽  
Architectural Features ◽  
Virtual Visits ◽  
Late Fifteenth ◽  
The Individual ◽  
First Time ◽  
The Relationship ◽  
The City

The tower in the tower. Recovery and 3D survey for virtual visits to the Torre Matta in OtrantoOtranto is one of the biggest ancient settlements in the Salento (Puglia), in the easternmost part of the Italian peninsula. This location has always affected the city’s history, which has a stratified system of defence. As a result of the Turkish invasion of 1480, the city was completely destroyed. During the counter-offensive of 1481 the city was reconquered by the Aragonese, who are credited with the reconstruction of the city and its defences, building high walls with circular towers (still visible and well conserved), which housed artillery pieces on the various floors of the casemates. Around the mid sixteenth century the existing defensive structures were enriched with bastions including the imposing pentagonal structure that incorporates the circular tower of the late fifteenth century, the so-called Torre Matta, facing the harbour. As part of recent recovery measures, the enormous room inside the bastion was completely emptied. This entailed removing all the accumulated material which, over the years, had come to fill the entire space. This material obscured the external wall of the fifteenth century tower enclosed within the bastion, of which, at the beginning of the work, only the stone corbels and the blind arches at the top were visible. The material had also prevented access via the only original entrance, on the south-east side, which was on the level of the moat. The stratified deposits to be removed were about 18 m deep, and the operation served to bring to light the entire room and the tower, making it possible for the first time to appreciate the relationship between the walls. To record the geometry of the individual architectural features, a 3D laser scan was performed, integrated with direct surveys. A three-dimensional model was created in order to enable virtual visits and disseminate knowledge of the monument.

Excess conductivity analysis for Y3−xNdxBa5−xCaxCu8O18−δ superconducting phase

2016 ◽  
Vol 30 (19) ◽  
pp. 1650115 ◽  
Author(s):  
M. ME. Barakat ◽  
A. I. Abou-Aly ◽  
R. Awad ◽  
N. S. Aly ◽  
S. Ibrahim
Keyword(s):  
Mean Field ◽  
Three Dimensional ◽  
Short Wave ◽  
Partial Substitution ◽  
Fermi Velocity ◽  
Superconducting Transition ◽  
Energy Formula ◽  
Lower Temperature ◽  
Strength Formula ◽  
Substitution Content

Superconducting samples of type [Formula: see text] substituted by both [Formula: see text] and [Formula: see text] ions were prepared by a solid-state reaction technique. These substitutions affect the phase formation, lattice parameters, grains formations and superconducting transition temperature [Formula: see text]. The change in these parameters is mainly due to the partial substitution of [Formula: see text] by [Formula: see text] ions rather than the partial substitution of [Formula: see text] by [Formula: see text] ions. The analysis of the electrical resistivity [Formula: see text] versus temperature above [Formula: see text] was carried out using Aslamazov–Larkin (AL) and Lawrence–Doniach (LD) models. Different fluctuation regions starting from high temperature up to [Formula: see text] were estimated, and denoted by short-wave (sw), two-dimensional (2D), three-dimensional (3D) and critical (cr) fluctuations. A distinct crossover temperature [Formula: see text] from 2D to 3D, in the mean field region (MFR), is shifted to lower temperature by increasing substitutions content. The superconducting parameters such as zero temperature coherence length along the [Formula: see text]-axis [Formula: see text], inter-layer coupling strength [Formula: see text], Fermi velocity [Formula: see text] of the carriers and Fermi energy [Formula: see text] were calculated as a function of substitution content.

scholarly journals Microstructure and paramagnetic Meissner effect of YBa2Cu3Oy nanowire networks

2020 ◽  
Vol 22 (12) ◽  
Author(s):  
A. L. Pessoa ◽  
A. Koblischka-Veneva ◽  
C. L. Carvalho ◽  
R. Zadorosny ◽  
M. R. Koblischka
Keyword(s):  
Sol Gel ◽  
Meissner Effect ◽  
Woven Fabric ◽  
Nanoporous Structure ◽  
Paramagnetic Meissner Effect ◽  
Nanowire Network ◽  
Flux Trapping ◽  
Solution Blow Spinning ◽  
Nanofiber Mats ◽  
Nanowire Networks

AbstractThe microstructure and magnetic characterizations of non-woven, fabric-like YBa2Cu3Oy (YBCO) nanofiber mats are reported. The samples were produced by solution blow spinning (SBS), starting from a sol-gel solution of the precursor materials in polyvinylpyrrolidone. In the present work, the nanowire network samples were morphologically characterized by scanning electron microscopy, and the superconducting properties were measured by magnetometry. An interesting feature is the appearance of a paramagnetic Meissner effect (PME) when field-cooling, firstly verified in that sort of sample. The PME appears only in very small applied magnetic fields, which is similar to previous observations of the PME on an artificially granular YBCO thin film, but distinctly different from bulk samples investigated in the literature. Thus, we explain the PME by flux trapping within the voids of the nanoporous structure of the nanofiber mats.

Semi-automated methods for 3-D reconstruction of macromolecular complexes

1995 ◽  
Vol 53 ◽  
pp. 42-43
Author(s):  
B. Carragher ◽  
M. Whittaker
Keyword(s):  
Three Dimensional ◽  
Time Saving ◽  
Macromolecular Complexes ◽  
Symmetry Properties ◽  
Dimensional Reconstruction ◽  
Experienced Operator ◽  
Projection Images ◽  
The Individual ◽  
Natural Symmetry

Techniques for three-dimensional reconstruction of macromolecular complexes from electron micrographs have been successfully used for many years. These include methods which take advantage of the natural symmetry properties of the structure (for example helical or icosahedral) as well as those that use single axis or other tilting geometries to reconstruct from a set of projection images. These techniques have traditionally relied on a very experienced operator to manually perform the often numerous and time consuming steps required to obtain the final reconstruction. While the guidance and oversight of an experienced and critical operator will always be an essential component of these techniques, recent advances in computer technology, microprocessor controlled microscopes and the availability of high quality CCD cameras have provided the means to automate many of the individual steps.During the acquisition of data automation provides benefits not only in terms of convenience and time saving but also in circumstances where manual procedures limit the quality of the final reconstruction.

Phonetic iconicity in the evaluative morphology of a sample of Indo-European, Niger-Congo and Austronesian languages

2010 ◽  
Vol 3 (2) ◽  
pp. 156-180 ◽  
Author(s):  
Renáta Gregová ◽  
Lívia Körtvélyessy ◽  
Július Zimmermann
Keyword(s):  
Three Dimensional ◽  
Sound Symbolism ◽  
Three Dimensional Model ◽  
Austronesian Languages ◽  
Place Of Articulation ◽  
European Languages ◽  
Phonetic Symbolism ◽  
The Individual ◽  
Core Vocabulary

Universals Archive (Universal #1926) indicates a universal tendency for sound symbolism in reference to the expression of diminutives and augmentatives. The research ( Štekauer et al. 2009 ) carried out on European languages has not proved the tendency at all. Therefore, our research was extended to cover three language families – Indo-European, Niger-Congo and Austronesian. A three-step analysis examining different aspects of phonetic symbolism was carried out on a core vocabulary of 35 lexical items. A research sample was selected out of 60 languages. The evaluative markers were analyzed according to both phonetic classification of vowels and consonants and Ultan's and Niewenhuis' conclusions on the dominance of palatal and post-alveolar consonants in diminutive markers. Finally, the data obtained in our sample languages was evaluated by means of a three-dimensional model illustrating the place of articulation of the individual segments.

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