scholarly journals Synthesis, structure and electromagnetic properties of FeCoAl/C nanocomposites

2021 ◽  
Vol 7 (3) ◽  
pp. 99-108
Author(s):  
Dmitriy G. Muratov ◽  
Lev V. Kozhitov ◽  
Egor V. Yakushko ◽  
Andrey A. Vasilev ◽  
Alena V. Popkova ◽  
...  
Keyword(s):  
Solid Solution ◽  
Magnetic Nanoparticles ◽  
Metal Salt ◽  
Volume Ratio ◽  
Coherent Scattering ◽  
Synthesis Temperature ◽  
Chemical Activity ◽  
Electromagnetic Properties ◽  
Magnetic Storage ◽  
Synthesis Conditions

Magnetic nanoparticles play an important role in rapidly developing advanced branches of science and industry, e.g. fabrication of magnetic storage media, synthesis of ferromagnetic liquids, medicine and chemistry. One problem faced in the usage of magnetic nanoparticles is their high chemical activity leading to oxidation in air and agglomeration. The chemical activity of magnetic nanoparticles stems from the contribution of their large specific surface to volume ratio. Carbon coating of nanoparticles reduces the interaction between nanoparticles. FeCoAl/C metal-carbon nanocomposites have been synthesized using IR pyrolysis of polymer/metal salt precursors. The effect of synthesis temperature (IR heating) in the range from 500 to 700 °C on the structure and composition of the nanomaterials has been studied. We show that the forming particles are the FeCoAl ternary solid solution with a FeCo based bcc lattice. An increase in the synthesis temperature from 500 to 700 °C leads to an increase in the coherent scattering region of three-component nanoparticles from 5 to 19 nm. An increase in the aluminum content from 20 to 30% relative to Fe and Co results in an increase in the size of the nanoparticles to 15 nm but this also entails the formation of a Co based solid solution having an fcc lattice. An increase in the nanocomposite synthesis temperature and a growth of the relative Al content as a result of a more complete carbonization and the structure-building effect of metals reduce the degree of amorphousness of the nanocomposite carbon matrix and lead to the formation of graphite-like phase crystallites having an ordered structure. The effect of synthesis temperature and relative content of metals on the electromagnetic properties (complex permittivity and permeability) of the synthesized nanocomposites has been studied. Synthesis conditions affect the radio absorption properties of the nanocomposites, e.g. reflection loss (RL) in the 3–13 GHz range.

scholarly journals New advances on Au–magnetic organic hybrid core–shells in MRI, CT imaging, and drug delivery

RSC Advances ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 6517-6525
Author(s):  
Fatemeh Mohajer ◽  
Ghodsi Mohammadi Ziarani ◽  
Alireza Badiei
Keyword(s):  
Magnetic Resonance Imaging ◽  
Drug Delivery ◽  
Magnetic Nanoparticles ◽  
Targeted Drug Delivery ◽  
Magnetic Storage ◽  
Resonance Imaging ◽  
Organic Hybrid ◽  
Storage Media ◽  
Targeted Drug ◽  
Magnetic Storage Media

Magnetic nanoparticles have been studied for scientific and technological applications such as magnetic storage media, contrast agents for magnetic resonance imaging, biolabelling, separation of biomolecules, and magnetic-targeted drug delivery.

Monoazo (Monohydrazone) pigments based on 2-naphthol and derivatives

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Robert Christie ◽  
Adrian Abel
Keyword(s):  
Metal Salt ◽  
Water Soluble ◽  
Anionic Dyes ◽  
Extensive Discussion ◽  
Synthesis Conditions ◽  
Organic Pigments ◽  
Amide Derivatives ◽  
The Individual ◽  
Coupling Components ◽  
Group 1

Abstract This chapter describes the range of industrial monoazo pigments based on the 2-naphthol (β-naphthol) ring system. This group includes some of the earliest organic pigments introduced commercially and is also numerically the largest group of products currently described in the Colour Index. Most of the pigments within this group are red (with a few oranges), thus complementing the azoacetoacetanilides, which are mostly yellows. Three groups of monoazonaphthol-based pigments may be identified categorized according to the chemical structure of the coupling components used in their synthesis. The first group contains products based on 2-naphthol itself, a second is based on amide derivatives of 3-hydroxy-2-naphthoic acid (naphtharylamides), and the third is a series of metal salt azo pigments. The historical development of these pigments, outlined in an early section of this chapter, originated in the late 19th century with pigments described as ‘lakes’, derived from water-soluble anionic dyes absorbed on to inert colorless substrates, which were the forerunners of products now referred to as metal salt pigments. The non-ionic 2-naphthol-based pigments were introduced soon after. In the early to mid-20th century, a series of monoazonaphtharylamide (Naphthol AS) pigments were developed and introduced commercially. The pigments of this type that are currently manufactured can be sub-divided into products containing a single amide group (group 1) and higher performance products containing more than one amide or sulfonamide groups. Several group 1 pigments have diminished in importance over the years, while some higher performing group 2 pigments have grown in importance. The molecular and crystal structures of the range of pigments are presented and discussed in relation to their performance characteristics. The manufacture of the pigments involves the reaction of a diazotized aromatic amine with the appropriate 2-naphthol-based coupling component, using synthesis conditions typical of phenolic coupling components, followed by conditioning aftertreatments that are typical for azo pigments in general. Finally, there is an extensive discussion of the wide-ranging applications in which the individual pigments are used. While the pigments are especially well-suited to printing ink applications, many products also find use in paints and a few in plastics.

Electrical Conductivity and Phase Transitions in Ferroelectric Solid Solutions Li0.17Na0.83ТауNb1-уO3 (y = 0 – 0.5) in High Pressure

2020 ◽  
Vol 310 ◽  
pp. 6-13
Author(s):  
Vadim V. Efremov ◽  
Mikhail N. Palatnikov ◽  
Yuriy V. Radyush ◽  
Olga B. Shcherbina
Keyword(s):  
Solid Solution ◽  
Electrical Conductivity ◽  
High Pressure ◽  
Phase Transitions ◽  
Solid Solutions ◽  
Synthesis Method ◽  
Ferroelectric Ceramic ◽  
Synthesis Temperature ◽  
Structure Phase ◽  
Ceramic Solid Solution

Ferroelectric ceramic solid solutions LixNa1-xTayNb1-yO3 (х = 0.17; у = 0 – 0.5) with the perovskite structure have been obtained by the thermobaric synthesis method. Particularities of their microstructure, elastic properties, electrical conductivity and permittivity have been researched. It has been established that an increase in the thermobaric synthesis temperature leads to a decrease in the Young’s modulus value. Specific static conductivity values have been determined; charge carrier activation enthalpies На have been calculated. The Curie temperature of the samples has been determined to decrease with an increase in tantalum content. A Ferroelectric ceramic solid solution Li0.17Na0.83Ta0.1Nb0.9O3 was shown to undergo four structure phase transitions in the temperature range 300-820 К. A Li0.17Na0.83Ta0.1Nb0.9O3 has been shown to be a high temperature superionic. Possible mechanisms of the detected phenomena are discussed.

scholarly journals Potential Toxicity of Iron Oxide Magnetic Nanoparticles: A Review

Molecules ◽  
2020 ◽  
Vol 25 (14) ◽  
pp. 3159 ◽  
Author(s):  
Nemi Malhotra ◽  
Jiann-Shing Lee ◽  
Rhenz Alfred D. Liman ◽  
Johnsy Margotte S. Ruallo ◽  
Oliver B. Villaflores ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Iron Oxide ◽  
Magnetic Nanoparticles ◽  
Cell Lines ◽  
Current Knowledge ◽  
Volume Ratio ◽  
The Body ◽  
Toxic Effects ◽  
Iron Oxide Magnetic Nanoparticles

The noteworthy intensification in the development of nanotechnology has led to the development of various types of nanoparticles. The diverse applications of these nanoparticles make them desirable candidate for areas such as drug delivery, coasmetics, medicine, electronics, and contrast agents for magnetic resonance imaging (MRI) and so on. Iron oxide magnetic nanoparticles are a branch of nanoparticles which is specifically being considered as a contrast agent for MRI as well as targeted drug delivery vehicles, angiogenic therapy and chemotherapy as small size gives them advantage to travel intravascular or intracavity actively for drug delivery. Besides the mentioned advantages, the toxicity of the iron oxide magnetic nanoparticles is still less explored. For in vivo applications magnetic nanoparticles should be nontoxic and compatible with the body fluids. These particles tend to degrade in the body hence there is a need to understand the toxicity of the particles as whole and degraded products interacting within the body. Some nanoparticles have demonstrated toxic effects such inflammation, ulceration, and decreases in growth rate, decline in viability and triggering of neurobehavioral alterations in plants and cell lines as well as in animal models. The cause of nanoparticles’ toxicity is attributed to their specific characteristics of great surface to volume ratio, chemical composition, size, and dosage, retention in body, immunogenicity, organ specific toxicity, breakdown and elimination from the body. In the current review paper, we aim to sum up the current knowledge on the toxic effects of different magnetic nanoparticles on cell lines, marine organisms and rodents. We believe that the comprehensive data can provide significant study parameters and recent developments in the field. Thereafter, collecting profound knowledge on the background of the subject matter, will contribute to drive research in this field in a new sustainable direction.

scholarly journals Bio-Catalysis and Biomedical Perspectives of Magnetic Nanoparticles as Versatile Carriers

2019 ◽  
Vol 5 (3) ◽  
pp. 42 ◽  
Author(s):  
Muhammad Bilal ◽  
Shahid Mehmood ◽  
Tahir Rasheed ◽  
Hafiz M. N. Iqbal
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Magnetic Nanoparticles ◽  
Molecular Level ◽  
State Of The Art ◽  
Volume Ratio ◽  
Controlled Drug Delivery ◽  
High Mass ◽  
Biological Interactions ◽  
Magnetic Carriers

In recent years, magnetic nanoparticles (MNPs) have gained increasing attention as versatile carriers because of their unique magnetic properties, biocatalytic functionalities, and capabilities to work at the cellular and molecular level of biological interactions. Moreover, owing to their exceptional functional properties, such as large surface area, large surface-to-volume ratio, and mobility and high mass transference, MNPs have been employed in several applications in different sectors such as supporting matrices for enzymes immobilization and controlled release of drugs in biomedicine. Unlike non-magnetic carriers, MNPs can be easily separated and recovered using an external magnetic field. In addition to their biocompatible microenvironment, the application of MNPs represents a remarkable green chemistry approach. Herein, we focused on state-of-the-art two majorly studied perspectives of MNPs as versatile carriers for (1) matrices for enzymes immobilization, and (2) matrices for controlled drug delivery. Specifically, from the applied perspectives of magnetic nanoparticles, a series of different applications with suitable examples are discussed in detail. The second half is focused on different metal-based magnetic nanoparticles and their exploitation for biomedical purposes.

Wood-based activated carbons for supercapacitors with organic electrolyte

Holzforschung ◽  
2015 ◽  
Vol 69 (6) ◽  
pp. 777-784 ◽  
Author(s):  
Galina Dobele ◽  
Aleksandrs Volperts ◽  
Galina Telysheva ◽  
Aivars Zhurinsh ◽  
Daria Vervikishko ◽  
...  
Keyword(s):  
Activated Carbons ◽  
Specific Capacity ◽  
Total Pore Volume ◽  
Synthesis Temperature ◽  
Raw Material ◽  
Organic Electrolyte ◽  
Electrochemical Characteristics ◽  
Activation Temperature ◽  
Synthesis Conditions ◽  
Ohmic Losses

Abstract The thermocatalytical synthesis conditions required for the activation of wood charcoal with NaOH in terms of the formation of pores in its structure were investigated. The present study was conducted to explore the potential application of activated carbons as electrodes in supercapacitors with organic electrolyte. The total pore volume and micro- and mesopore ratio were controlled by the activation temperature and alkali addition rate. The working characteristics of carbon electrodes (e.g., specific capacity and ohmic losses) in supercapacitors are strongly influenced by the properties of the pores in their structures. Herein, the optimal ratio of raw material to activator and activation temperature are established: an increase in the ratio of NaOH to carbonizate rate by a factor of 2 and setting the synthesis temperature at 700°C positively influence the electrochemical characteristics of supercapacitors and provide them with specific capacities of up to 160 F g-1.

Heating of Zn-Substituted Manganese Ferrite Magnetic Nanoparticles in Alternating Magnetic Field

2015 ◽  
Vol 233-234 ◽  
pp. 761-765
Author(s):  
T.M. Elkhova ◽  
A.K. Yakushechkina ◽  
A.S. Semisalova ◽  
Y.K. Gun’ko ◽  
Yu.I. Spichkin ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Specific Absorption Rate ◽  
Metal Salt ◽  
Relaxation Mechanism ◽  
Manganese Ferrite ◽  
Zn Content ◽  
Magnetic Liquids ◽  
Naoh Solution ◽  
Brown Relaxation ◽  
Co Precipitation

In this report, were studied the heating capability of magnetic nanoparticles (MNps) made from Zn-substituted manganese ferrite compounds ZnxMn1-xFe2O4 with Zn content varying from 0% to 90%. The MNps of diameter 5-25 nm were synthesized by co-precipitation of metal salt solution with NaOH solution. It was shown, that specific absorption rate (SAR) for the compound with Zn content of 20% is bigger than the other ones exhibited 1.5 W/g. Also SAR for the magnetic liquids made of the MNps shows bigger SAR values, which indicates the Brown relaxation mechanism in the system.

Effect of Synthesis Conditions and Actinide Contents on Phase Composition of Actinide Bearing Ceramics

2003 ◽  
Vol 807 ◽  
Author(s):  
A. G. Ptashkin ◽  
S. V. Stefanovsky ◽  
S. V. Yudintsev ◽  
S. A. Perevalov
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Phase Composition ◽  
Fluorite Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Synthesis Conditions ◽  
Reducing Conditions ◽  
Dispersive System ◽  
Scanning Electron

ABSTRACTPu-bearing zirconolite and pyrochlore based ceramics were prepared by melting under oxidizing and reducing conditions at 1550 °C. 239Pu content in the samples ranged between ∼10 and ∼50 wt.%. Phase composition of the ceramics and Pu partitioning were studied using X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive system (SEM/EDS). Major phases in the samples were found to be the target zirconolite and pyrochlore as well as a cubic fluorite structure oxide. Normally the Pu content in the Pu host phases was 10–12 wt.%. This corresponds to the Pu content recommended for matrices for immobilization of excess weapons plutonium. At higher Pu content (up to 50 wt.%) additional phases, such as a PuO2-based cubic fluorite-structured solid solution, perovskite, and rutile were found.

Microstructure and Properties of Ferrite/Organic Nanocomposite Prepared with Microemulsion Method

2012 ◽  
Vol 722 ◽  
pp. 31-38 ◽  
Author(s):  
Xu Zheng ◽  
Shu Hui Yu ◽  
Rong Sun ◽  
Wen Hu Yang ◽  
Ru Xu Du
Keyword(s):  
Magnetic Nanoparticles ◽  
Saturation Magnetization ◽  
Organic Compounds ◽  
Nanocomposite Film ◽  
Volume Ratio ◽  
Tween 80 ◽  
Reducing Agent ◽  
Good Stability ◽  
Molar Ratio ◽  
Microemulsion Method

A magnetite composite composed of the organic compounds and Fe3O4nanoparticles was prepared with microemulsion method. The Tween 80 and ammonia were used as surfactant and reducing agent, respectively, in synthesizing the Fe3O4nanoparticles. The experimental results showed that the composite possessed good stability while the volume ratio of Tween 80 to butanol was 0.4 and the molar ratio of NH4OH to Fe3+was 14.6. The saturation magnetization of the composite depends on the molar ratio of NH4OH to Fe3+. The mechanism of this stable Fe3O4paste was realized by the Fe3O4nanocomposite film using TEM. The microstructures of the film show that the magnetic nanoparticles in the composite are surrounded by Tween 80, which separates the magnetic nanoparticles and leads to good stability.

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