scholarly journals Microemulsion Synthesis of Iron Core/Iron Oxide Shell Magnetic Nanoparticles and Their Physicochemical Properties

2012 ◽  
Vol 1416 ◽  
Author(s):  
Katsiaryna Kekalo ◽  
Katherine Koo ◽  
Evan Zeitchick ◽  
Ian Baker
Keyword(s):  
Magnetic Nanoparticles ◽  
Room Temperature ◽  
Iron Nanoparticles ◽  
Inert Atmosphere ◽  
Oxide Shell ◽  
Iron Core ◽  
Silica Layer ◽  
Infra Red ◽  
C 30 ◽  
Microemulsion Synthesis

ABSTRACTIron magnetic nanoparticles were synthesized under an inert atmosphere via the reaction between FeCl3 and NaBH4 in droplets of water in a microemulsion consisting of octane with cetyl trimethylammonium bromide and butanol as surfactants. A thin Fe3O4 layer was produced on the iron nanoparticles using slow, controlled oxidation at room temperature. A silica shell was deposited on the Fe3O4 using 3-aminopropyltrimethoxysilane following the method of Zhang et al. [Mater. Sci. Eng. C 30 (2010) 92–97]. The structure and chemistry of the resulting nanoparticles were studied using variety of methods and their magnetic properties were determined. The diameter of the iron core was typically 8-16 nm, while the thickness of the Fe3O4 shell was 2-3 nm. The presence of the silica layer was confirmed using Fourier transform infra-red spectroscopy and the number of NH2-groups on each nanoparticle was determined based on colorimetric tests using ortho-phthalaldehyde.

Peparation and Magnetic Propriety of Carbon-Coated Iron Magnetic Nanoparticles by Starch Coating Method

2012 ◽  
Vol 164 ◽  
pp. 17-20
Author(s):  
Jin Chen ◽  
Hai Yan Zhang
Keyword(s):  
Magnetic Properties ◽  
Magnetic Nanoparticles ◽  
Iron Nanoparticles ◽  
Low Cost ◽  
Carbon Layer ◽  
Spherical Particles ◽  
Ferric Nitrate ◽  
Iron Core ◽  
Scanning Calorimetry ◽  
Carbon Coated

We synthesized carbon-coated iron magnetic nanoparticles by a low cost method using Ferric nitrate as the iron precursor and starch as both reductive agent and carbon source under H2 atmosphere. The structure, size distribution, phase composition, magnetic properties and oxidation resistance of the particles were investigated by transmission electron microscopy, X-ray diffraction, vibrating sample magnetometry and differential scanning calorimetry. The results show that the carbon-coated iron nanoparticles are spherical particles with a diameter of 20-40 nm. They are particles of core-shell structure with an iron core inside and an onion skin carbon layer outside, carbon layer can protect inner iron core from been oxidized, the hysteresis curves show that they are super paramagnetic materials. At the same time the annealing can change the magnetic properties of carbon coated iron nanoparticles.

Zero-valent iron core-iron oxide shell nanoparticles coated with silica and gold with high saturation magnetization

2021 ◽  
Author(s):  
Milad Mehdipour ◽  
Lucy O Gloag ◽  
Jiaxin Lian ◽  
Richard Tilley ◽  
John Justin Gooding
Keyword(s):  
Iron Oxide ◽  
Magnetic Nanoparticles ◽  
Saturation Magnetization ◽  
Zero Valent Iron ◽  
Oxide Shell ◽  
Iron Core ◽  
High Saturation Magnetization ◽  
Shell Nanoparticles ◽  
Magnetic Cores ◽  
New Type

A new type of gold-coated magnetic nanoparticles with a strongly magnetic zero-valent iron core-iron oxide shell as magnetic cores were synthesized. The small size of the magnetic cores and the...

Intercluster Interaction and Magnetic Interaction between Iron Core and Iron Oxide Shell in Core-Shell Nanoclusters

2012 ◽  
Vol 1406 ◽  
Author(s):  
Maninder Kaur ◽  
Qi Yao ◽  
You Qiang
Keyword(s):  
Iron Oxide ◽  
Room Temperature ◽  
Magnetic Interaction ◽  
Oxide Shell ◽  
Iron Core ◽  
Core Shell ◽  
Isothermal Remanent Magnetization ◽  
Intercluster Interaction ◽  
Iron Iron ◽  
Iron Oxide Core

ABSTRACTThe intercluster interactions of iron/iron oxide core shell nanoclusters have been investigated, and their dependence on cluster size (d) has been discussed. A cluster deposition system is used to prepare core-shell nanoclusters with different d, varying from 9 to 14 nm.Transmission Electron Microscopy has been used for physical characterization, and Vibrating Sample Magnetometer for magnetic study. The cluster – cluster interactions have been investigated by field dependent isothermal remanent magnetization (IRM) and dc demagnetization (DCD) measurements at room temperature. Henkel plot shows more negative deviation from non- interacting case for bigger size nanoclusters than smaller size clusters.

Electron Microscopy of Human Gallstones

1971 ◽  
Vol 29 ◽  
pp. 296-297
Author(s):  
C. Wolpers ◽  
R. Blaschke
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Bile Pigment ◽  
X Ray Diffraction ◽  
Triclinic Crystal System ◽  
X Ray ◽  
Follow Up Study ◽  
Infra Red ◽  
Main Components

Scanning microscopy was used to study the surface of human gallstones and the surface of fractures. The specimens were obtained by operation, washed with water, dried at room temperature and shadowcasted with carbon and aluminum. Most of the specimens belong to patients from a series of X-ray follow-up study, examined during the last twenty years. So it was possible to evaluate approximately the age of these gallstones and to get information on the intensity of growing and solving.Cholesterol, a group of bile pigment substances and different salts of calcium, are the main components of human gallstones. By X-ray diffraction technique, infra-red spectroscopy and by chemical analysis it was demonstrated that all three components can be found in any gallstone. In the presence of water cholesterol crystallizes in pane-like plates of the triclinic crystal system.

scholarly journals Enhanced preservation of vacuum-packaged Atlantic salmon by hyperbaric storage at room temperature versus refrigeration

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Liliana G. Fidalgo ◽  
Mário M. Q. Simões ◽  
Susana Casal ◽  
José A. Lopes-da-Silva ◽  
Ivonne Delgadillo ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Microbial Activity ◽  
Room Temperature ◽  
Energy Savings ◽  
Textural Properties ◽  
Storage Conditions ◽  
Volatile Profile ◽  
Fragmentation Index ◽  
C 30 ◽  
Water Holding

AbstractHyperbaric storage at room temperature (HS/RT: 75 MPa/25 °C) of vacuum-packaged fresh Atlantic salmon (Salmo salar) loins was studied for 30 days and compared to atmospheric pressure at refrigerated temperatures (AP/5 °C, 30 days) and RT (AP/25 °C, 5 days). Most of the fatty acids were not affected by storage conditions, with only a slight decrease of docosahexaenoic acid (DHA) content (n-3 polyunsaturated fatty acid) for AP samples, reflected in the lower polyene index values obtained and higher oxidation extent. For HS, a lower lipid oxidation extension and a slower increase of myofibrillar fragmentation index values were observed, when compared to AP samples. The volatile profile was similar for the HS and fresh samples, with the HS samples retaining fresh-like alcohols and aldehydes components, which disappeared in AP samples, mainly in AP/25 °C samples. The volatile profile for AP samples (5 and 25 °C) revealed mostly spoilage-like compounds due to microbial activity. Drip loss increased progressively during the 30 days of storage under HS, while a slight decrease of water holding capacity after 5 days was observed, increasing further after 30 days. Regarding textural properties, only resilience was affected by HS, decreasing after 30 days. So, HS/RT could represent an interesting extended preservation methodology of fresh salmon loins, since allows retaining important physicochemical properties for at least 15 days, while refrigeration after 5 days showed already volatile spoilage-like compounds due to microbial activity. Furthermore, this methodology allows additional considerable energy savings when compared to refrigeration.

scholarly journals Silica Layer Used in Sensor Fabrication from a Low-Temperature Silane-Free Procedure

Chemosensors ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 32
Author(s):  
Pei-Cheng Jiang ◽  
Yu-Ting Chow ◽  
Chi-Wei Chien ◽  
Cheng-Hsun-Tony Chang ◽  
Chii-Ruey Lin
Keyword(s):  
Room Temperature ◽  
Chemical Vapor ◽  
Industrial Safety ◽  
Silica Layer ◽  
Silica Films ◽  
Sensor Fabrication ◽  
Vapor Deposition Technique ◽  
Safety Design ◽  
Biogenic Polyamines ◽  
Si Wafer

Silica (SiO2, silicon dioxide—a dielectric layer commonly used in electronic devices) is widely used in many types of sensors, such as gas, molecular, and biogenic polyamines. To form silica films, core shell or an encapsulated layer, silane has been used as a precursor in recent decades. However, there are many hazards caused by using silane, such as its being extremely flammable, the explosive air, and skin and eye pain. To avoid these hazards, it is necessary to spend many resources on industrial safety design. Thus, the silica synthesized without silane gas which can be determined as a silane-free procedure presents a clean and safe solution to manufactures. In this report, we used the radio frequency (rf = 13.56 MHz) plasma-enhanced chemical vapor deposition technique (PECVD) to form a silica layer at room temperature. The silica layer is formed in hydrogen-based plasma at room temperature and silane gas is not used in this process. The substrate temperature dominates the silica formation, but the distance between the substrate and electrode (DSTE) and the methane additive can enhance the formation of a silica layer on the Si wafer. This silane-free procedure, at room temperature, is not only safer and friendlier to the environment but is also useful in the fabrication of many types of sensors.

Magnetic nanoparticles-doped silica layer reported on ion-exchanged glass waveguide: towards integrated magneto-optical devices

2010 ◽  
Author(s):  
Hadi Amata ◽  
François Royer ◽  
Fadi Choueikani ◽  
Damien Jamon ◽  
Jean-Emmanuel Broquin ◽  
...  
Keyword(s):  
Magnetic Nanoparticles ◽  
Optical Devices ◽  
Silica Layer ◽  
Glass Waveguide

scholarly journals Synthesis and Magnetic Characterization of Graphite-Coated Iron Nanoparticles

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
A. M. Espinoza-Rivas ◽  
M. A. Pérez-Guzmán ◽  
R. Ortega-Amaya ◽  
J. Santoyo-Salazar ◽  
C. D. Gutiérrez-Lazos ◽  
...  
Keyword(s):  
Magnetite Nanoparticles ◽  
Iron Nanoparticles ◽  
Vapour Deposition ◽  
Magnetic Measurements ◽  
Chemical Vapour ◽  
Hydrogen Atmosphere ◽  
Iron Core ◽  
Carbon Excess ◽  
Raman Characterization

Graphite-coated iron nanoparticles were prepared from magnetite nanoparticles by chemical vapour deposition (CVD) under methane and hydrogen atmosphere. After being purified from carbon excess, graphite-coated iron nanoparticles were tested for morphological and magnetic properties. It was found that, during the thermal process, magnetite nanoparticles 6 nm in size coalesce and transform into graphite-coated iron 200 nm in size, as revealed by scanning electron microscopy (SEM). Raman characterization assessed that high-quality graphite coats the iron core. Magnetic measurements revealed the phase change (magnetite to iron) as an increase in the saturation magnetization from 50 to 165 emu/g after the CVD process.

Local Structure and Er3+ Emission from Pseudo-Amorphous GaN:Er Thin Films

1998 ◽  
Vol 536 ◽  
Author(s):  
S. B. Aldabergenova ◽  
M. Albrecht ◽  
A. A. Andreev ◽  
C. Inglefield ◽  
J. Viner ◽  
...  
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Amorphous Matrix ◽  
Broad Band ◽  
Resonant Absorption ◽  
Absorption Bands ◽  
Host Matrix ◽  
Transmission Electron ◽  
Infra Red ◽  
Band Edge Luminescence

AbstractWe report on strong Er3+ luminescence in the visible and infra-red regions at room temperature in amorphous GaN:Er thin films prepared by DC magnetron co-sputtering. The intensity of the Er3+ luminescence at 1.535 μm corresponding to 4I13/2 → 4I15/2 transitions is greatly enhanced after annealing at 750°C. In this material GaN crystallites have formed and embedded in the continuous amorphous matrix. The crystallites are 4 to 7 nm in diameter as analyzed by high resolution transmission electron microscopy. The absorption edge, extending three orders of magnitude in absorption coefficient in the spectral range from 0.5 to 3.5 eV, is superimposed on resonant absorption bands of Er3+ ions.The total photoluminescence spectrum consists of welldefined Er3+ luminescence peaks imposed on a broad band edge luminescence from the amorphous GaN host matrix.

Intracellular accumulation and immunological responses of lipid modified magnetic iron nanoparticles in mouse antigen processing cells

2017 ◽  
Vol 5 (8) ◽  
pp. 1603-1611 ◽  
Author(s):  
Chenmeng Qiao ◽  
Jun Yang ◽  
Lei Chen ◽  
Jie Weng ◽  
Xin Zhang
Keyword(s):  
Magnetic Nanoparticles ◽  
Immune Responses ◽  
Antigen Processing ◽  
Iron Nanoparticles ◽  
Intracellular Accumulation ◽  
Immunological Responses ◽  
Modified Magnetic Nanoparticles

Lipid modified magnetic nanoparticles could enhance the intracellular accumulation and immune responses of mouse antigen processing cells.

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