scholarly journals Synthesis and Magnetic Properties of Ni and Carbon Coated Ni by Levitational Gas Condensation (LGC)

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Young Rang Uhm ◽  
Chang Kyu Rhee
Keyword(s):  
Room Temperature ◽  
Spherical Particles ◽  
Coated Particles ◽  
Gas Condensation ◽  
Initial Magnetization ◽  
Coated Metal ◽  
Thin Carbon ◽  
Carbon Coated ◽  
Superparamagnetic State ◽  
Micron Powder

The nickel (Ni), and carbon coated nickel (Ni@C) nanoparticles were synthesized by levitaional gas condensation (LGC) methods using a micron powder feeding (MPF) system. Both metal and carbon coated metal nano powders include a magnetic ordered phase. The synthesis by LGC yields spherical particles with a large coercivity. The abnormal initial magnetization curve for Ni indicates a non-collinear magnetic structure between the core and surface layer of the particles. The carbon coated particles had a core structure diameter at and below 10 nm and were covered by 2-3 nm thin carbon layers. The hysteresis loop of the as-prepared Ni@Cs materials with unsaturated magnetization shows a superparamagnetic state at room temperature.

scholarly journals HCl Gas Sensor Coating Based on Poly(N-isopropylacrylamide) Nanoparticles Prepared from Water-Methanol Binary Solvent

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3283 ◽  
Author(s):  
Masanobu Matsuguchi ◽  
Shinnosuke Fujii
Keyword(s):  
Room Temperature ◽  
Pure Water ◽  
Electron Microscopic Observation ◽  
Spherical Particles ◽  
Binary Solvent ◽  
Electron Microscopic ◽  
Coated Nanoparticles ◽  
Water Solvent ◽  
Scanning Electron Microscopic ◽  
Hcl Gas

Poly(N-isopropylacrylamide) (PNIPAM) nanoparticles formed in water-methanol binary solvent were successfully deposited on a resonator surface at room temperature by exploiting the cononsolvency effect on the phase transition of PNIPAM aqueous solutions. Scanning electron microscopic observation revealed that the nanoparticles were secondary and made up of agglomerated primary spherical particles of about 10-nm diameter, buried in the film. The magnitude of the sensor response toward HCl gas was larger than that of the nanoparticle sensor prepared from pure water solvent, and the sensitivity to 1 ppm of HCl of sensor-coated nanoparticles based on the present method was 3.3 Hz/ppm. The recovery of the sensors was less than 90% at first cycle measurement, but had improved to almost 100% at the third cycle.

Electron Microscopy Study of Submicron Size Antiferromagnetic KMnF3 Nanoparticles and Their Self-assembly

2003 ◽  
Vol 775 ◽  
Author(s):  
Jeffrey Anderson ◽  
Rubi Garcia ◽  
Weilie L. Zhou
Keyword(s):  
Electron Microscopy ◽  
Self Assembly ◽  
Room Temperature ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Submicron Particles ◽  
Spherical Particles ◽  
Large Area ◽  
Homogeneous Crystal ◽  
Field Emission Electron Microscopy

AbstractSubmicron KMnF3 cubic and spherical nanoparticles were synthesized using the reverse micelle method. The nanostructures of the nanocrystals were studied by field emission electron microscopy and transmission electron microscopy. KMnF3 nanocrystals synthesized at room temperature started with cubic submicron particles (∼100 nm) and consisted of KMnF3 nanocrystallites (10-15 nm). As the reaction continued, the nanocrystals fused together and transformed into perfect cubic nanocrystals. Spherical beads composed of KMnF3 nanocrystallites were observed at low temperature synthesis. As the reaction continued, the spherical particles grew larger, however, no characteristic cubic shape of KMnF3 nanoparticles were observed. Even as they grew larger, there was no evidence of homogeneous crystal morphology as seen in the room temperature samples. Cubic shape KMnF3 nanocrystals were self-assembled into large area self-assembling patterns.

EFFECTIVE MAGNETIC ANISOTROPY AND COERCIVITY IN Fe NANOPARTICLES PREPARED BY INERT GAS CONDENSATION

2006 ◽  
Vol 20 (01) ◽  
pp. 37-47
Author(s):  
LUBNA RAFIQ SHAH ◽  
BAKHTYAR ALI ◽  
S. K. HASANAIN ◽  
A. MUMTAZ ◽  
C. BAKER ◽  
...  
Keyword(s):  
Room Temperature ◽  
Size Range ◽  
Magnetic Measurements ◽  
Uniaxial Anisotropy ◽  
Inert Gas ◽  
Condensation Process ◽  
Gas Condensation ◽  
Inert Gas Condensation ◽  
Fe Nanoparticles ◽  
Characterization Studies

We present magnetic measurements on iron ( Fe ) nanoparticles in the size range 10–30 nm produced by the Inert Gas Condensation process (IGC). Structural characterization studies show the presence of a core/shell structure, where the core is bcc Fe while the surface layer is Fe -oxide. Analysis of the magnetic measurements shows that the nanoparticles display very large uniaxial anisotropy, K eff ≈3 - 4 × 106 erg/cc. The observed room temperature coercivities lie in the range ≈600 – 973 Oe , much larger than those expected from the Stoner–Wohlfarth model using the bulk iron anisotropy. It can be inferred from the coercivity variation with the particle size that there is a general trend of the coercivity increasing with size, culminating finally in a decrease for high sizes (30 nm) possibly due to the onset of non-coherent magnetization reversal processes.

Preparation of Magnetically Soft, Highly-Densified Fe Cluster-Assembled Films by Impact Cluster Deposition

2006 ◽  
Vol 11-12 ◽  
pp. 595-598
Author(s):  
Dong Liang Peng ◽  
K. Sumiyama ◽  
H. Yamada ◽  
Takehiko Hihara ◽  
T. Uchida
Keyword(s):  
Room Temperature ◽  
Magnetic Behavior ◽  
Cluster Beam ◽  
Frequency Range ◽  
Soft Magnetic ◽  
Size Change ◽  
Gas Condensation ◽  
Cluster Deposition ◽  
The Impact ◽  
High Cluster

Highly-densified Fe cluster-assembled films were obtained at room temperature by an energetic cluster deposition. Fe clusters were produced using a plasma-gas-condensation (PGC)-type cluster deposition apparatus with a high cluster productivity. Ionized clusters in a cluster beam were electrically accelerated and directly deposited onto a substrate together with neutral clusters from the same cluster source. By increasing the impact energy of the ionized clusters up to about 1 eV/atom, the obtained cluster-assemblies have packing fractions higher than 0.8 without any serious size change, and result in a soft magnetic behavior up to a frequency range of few hundred MHz.

scholarly journals Forming pressure effect on microstructure and mechanical properties of nanocrystalline aluminum synthesized by inert gas condensation

2019 ◽  
Vol 79 ◽  
pp. 02002
Author(s):  
Shangshu Wu ◽  
Zhou Yu ◽  
Junjie Wang ◽  
Hanxin Zhang ◽  
Chaoqun Pei ◽  
...  
Keyword(s):  
Room Temperature ◽  
High Vacuum ◽  
Inert Gas ◽  
Helium Atmosphere ◽  
Gas Condensation ◽  
Inert Gas Condensation ◽  
In Situ Forming ◽  
Nanocrystalline Aluminum ◽  
Al Powder

The preparation of nanocrystalline aluminum (NC Al) was conducted in two steps. After the NC Al powder was synthesized by an Inert gas condensation (IGC) method in a helium atmosphere of 500 Pa, the NC Al powder was in-situ compacted into a pellet with a 10 mm diameter and 250 μm-300 μm thickness in a high vacuum (10-6 Pa-10-7 Pa) at room temperature. The NC Al samples were not exposed to air during the entire process. After the pressure reached 6 GPa, the relative density could reach 99.83%. The results showed that the grain size decreased with the increased of in-situ forming pressure. The NC Al samples present obvious ductile fracture, and the tensile properties were greatly changed with the increase of forming pressure.

Über die Korrelation zwischen Partikellänge und Infektiosität beim Vergilbungsvirus der Rüben

1958 ◽  
Vol 13 (1) ◽  
pp. 19-27 ◽  
Author(s):  
Karl-Wolfgang Mundry
Keyword(s):  
Sugar Beet ◽  
Room Temperature ◽  
Distribution Curve ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Infectious Agent ◽  
Minimal Length ◽  
Spherical Particles ◽  
Normal Length ◽  
Beet Yellows Virus

Crude leaf sap of plants suffering from sugar beet yellows was partially purified by density gradient centrifugation in the cold at different values of pʜ (6,2-9,0). After standing over night at 2° C the material was dialysed against buffer of pʜ 6,8 at room temperature. - As estimated by electron microscopy the most frequent length of the threadlike particles (Fig. 2) which were believed to be the infectious agent of sugar beet yellows shows a gradual shift from longer to shorter ones with rising pʜ (Fig. 1 a-e). The infectivity of the suspensions depends upon the pʜ of the preparation too. From the distribution curve of the particle lengths the relative concentrations of particles with different given minimal lengths were estimated. The dependence from the pʜ of the preparation of these relative concentrations was compared with that of the infectivity. Best agreement was observed with particles of 12 700 - 12 800 A minimal length (Fig. 3). This length seems to be identical with the “normal length” of the particles found in exsudates (12 400 -12 500 A). From these results it was concluded that a) particles which possess the normal length as found in exsudates are the infective entities of this disease, b) shorter particles are non-infectious, c) the infectious entities of the sugar beet yellows virus are of the threadlike type. There is no evidence that spherical particles are necessary for starting an infection with the sugar beet yellows virus.

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.

N-doped Carbon-coated Metal Sulfides/Phosphides Derived from Protic Salts for Oxygen Evolution Reaction

ChemCatChem ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 1185-1191 ◽  
Author(s):  
Jiusheng Jiang ◽  
Jianping Chen ◽  
Pingping Jiang ◽  
Yan Leng ◽  
Wei Jin
Keyword(s):  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Metal Sulfides ◽  
Coated Metal ◽  
Carbon Coated
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