scholarly journals Magnetic nanoparticles for components of MRI diagnostics and electronic devices

2021 ◽  
pp. 12-19
Author(s):  
Alina S. Korsakova ◽  
Dzmitry A. Kotsikau ◽  
Kanstantsin S. Livanovich ◽  
Tatsiana G. Shutava ◽  
Yulyan S. Haiduk ◽  
...  
Keyword(s):  
Magnetic Particles ◽  
Single Phase ◽  
Electronic Devices ◽  
Practical Interest ◽  
Structural Features ◽  
Partial Replacement ◽  
Colloidal Solutions ◽  
Diallyldimethylammonium Chloride ◽  
Cationic Distribution ◽  
Mri Diagnostics

The formation of single-phase solid solutions of iron oxide and manganese oxide with a spinel structure in MnxFe3 – xO4 system (x = 0; 0.3; 0.6; 0.8; 1.0; 1.2; 1.4; 1.8) has been established by methods of X-ray phase analysis and infrared spectroscopy. The maximum saturation magnetization was found for the composition Mn0.3 Fe2.7O4 (Ms = 68 A ⋅ m2 ⋅ kg−1 at 300 K and Ms = 85 A ⋅ m2 ⋅ kg−1 at 5 K), which is associated with a change in the cationic distribution over tetrahedral and octahedral voids. The materials obtained were stabilized in the form of colloidal solutions using a number of polyelectrolytes. It was found that poly(diallyldimethylammonium chloride) (PDDA) had the best stabilizing effect due to its structural features. A method for controlling the magnetic properties of magnetite by partial replacement of iron ions in the magnetite structure with manganese is proposed. Changing the magnitude of the magnetization and coercive force is possible by changing the degree of substitution. Relatively high values of specific magnetization, as well as uniformity of magnetic particles in size, can be of practical interest, for the manufacture of contrast agents in MRI diagnostics.

Synthesis of Biocompatible Magnetic Iron Oxide (γ-Fe2O3 and Fe3O4) Nanoparticles by a Modified Polyol Process for Biomedical Applications

2010 ◽  
Vol 1256 ◽  
Author(s):  
Georgia Basina ◽  
Ioannis Panagiotopoulos ◽  
Eamonn Devlin ◽  
George Hadjipanayis ◽  
Levent Colak ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Magnetic Particles ◽  
Polyol Process ◽  
X Rays ◽  
Colloidal Solutions ◽  
Heating Rates ◽  
Fast Heating ◽  
Ft Ir ◽  
Magnetite Phase ◽  
Ft Ir Spectroscopy

AbstractHighly crystalline superparamagnetic Fe3O4 nanoparticles coated by poly-vinylpyrrolidone (PVP) were prepared by simultaneous thermal decomposition of ferrous and ferric inorganic salts in polyethylene glycol (PEG) with molecular weight 200. The magnetic particles have a diameter in the range of 8-15 nm, and after exchange with citric acid diammonium salt, they transform into very stable super hydrophilic colloidal solutions. The presence of magnetite phase was confirmed using powder X-rays diffraction (XRD) and Mössbauer spectroscopy, while thermogravimetric analysis and FT-IR spectroscopy confirmed the presence of PVP or citrate anions on the nanoparticles surface. The magnetic properties revealed superparamagnetic behavior, with the composite material showing a saturation magnetization up to 57 emu/g. The Fe3O4 nanoparticles prepared by this modified polyol process are suitable for biomedical applications because of the biocompatibility of citrate anions. Magnetic hyperthermia experiments in neutral water solutions shows that the particles induce fast heating rates with specific absorption rate (SAR) values which reached 57.53 W/gFe, when the concentration of iron is 11.2 mgFe/ml.

Cooling of Microelectronic Devices Packaged in a Single Chip Module Using Single Phase Refrigerant R-123

2009 ◽  
Author(s):  
Tushara Pasupuleti ◽  
Satish G. Kandlikar
Keyword(s):  
Single Phase ◽  
Cooling System ◽  
Electronic Devices ◽  
Working Fluid ◽  
Practical Application ◽  
Microelectronic Device ◽  
Single Chip ◽  
Microelectronic Devices ◽  
Cooling Devices ◽  
Microchannel Cooling

An approach towards practical application of microchannel cooling system is necessary as the demand of high power density devices is increasing. Colgan et. al. [1] have designed a unit known as Single Chip Module (SCM) by considering the practical issues for packaging a microchannel cooling system with a microelectronic device. The performance of the SCM has already been investigated by using water as working fluid by Colgan et. al. [1]. Considering the actual working conditions, water cannot be used in electronic devices as the working fluid because any leakage may lead to system damage. Alternative fluids like refrigerants were considered. In this research, the performance of SCM has been studied by using refrigerant R-123 as working fluid and compared with water cooled system. Cooling of 83.33 W/cm2 has been achieved for a powered area of 3 cm2 by maintaining chip temperature of 60°C. The heat transfer co-efficient obtained at a flowrate of 0.7 lpm was 34.87 kW/m2-K. The results obtained indicate that from a thermal viewpoint, R-123 can be considered as working fluid for microelectronic cooling devices.

Separated-PI Control Strategy and Stability Analysis of a Single-Phase Inverter Connected to the Grid with a LCL Filter

2013 ◽  
Vol 291-294 ◽  
pp. 2464-2469
Author(s):  
Dian Li Hou ◽  
Qing Fan Zhang ◽  
Xiao Liu
Keyword(s):  
Control Strategy ◽  
Single Phase ◽  
Dynamic Performance ◽  
Structural Features ◽  
Lcl Filter ◽  
Phase Inverter ◽  
Hurwitz Stability ◽  
Single Phase Inverter ◽  
Grid Connected Inverter ◽  
The Stability

Because of the powerful filtering ability the third-order LCL filters has been widely used in grid-connected inverters, but there are some problems to be solved on systems stability and control accuracy. A separated-PID control strategy has been proposed according to the PID characteristics and the structural features of a single-phase inverter connected to the grid with a LCL filter. This control strategy has some advantages as a strong dynamic tacking stability, and the system output has a small steady state error. A detailed description is presented on this control strategy applied in the single-phase grid inverter with a LCL filter. According to the Routh-Hurwitz stability criterion, the stability of a grid-connected inverter system based on the proposed control strategy has been analyzed. Finally, waveforms of this inverter have been presented through a simulation to show the steady and dynamic performance of the proposed scheme.

MAGNETIC INTERACTION OF THE COMPOSITE MIXTURES Nd-Fe-B/Sm2Co17

2006 ◽  
Vol 20 (24) ◽  
pp. 1543-1548 ◽  
Author(s):  
SHUXIN BAI ◽  
SHUN LI ◽  
HONG ZHANG ◽  
KE CHEN ◽  
HONGNIAN CAI
Keyword(s):  
Magnetic Field ◽  
Phase Behavior ◽  
Mass Fraction ◽  
Magnetic Particles ◽  
Single Phase ◽  
Magnetic Interaction ◽  
Demagnetization Curve ◽  
Energy Product ◽  
Bonded Magnet ◽  
Low Magnetic Field

Hybrid-bonded isotropic Nd-Fe-B /anisotropic Sm 2 Co 17 magnets with different mass fraction of Sm 2 Co 17 powders had been analyzed with the aid of magnetization and demagnetization curves. It was found that the Henkel plot of magnet with 10 wt.% Sm 2 Co 17 lies above the Wohlfarth line at low magnetic field but goes down slowly and then lies below the Wohlfarth line at high magnetic field. This shows magnetizing interaction at first and demagnetizing interaction at last, and presents an s-shaped behavior that has been seen frequently in nanocomposite exchange-coupled magnets. The demagnetization curve of 10 wt.% Sm 2 Co 17 content hybrid-bonded magnet exhibits a magnetically single phase behavior which has also been seen frequently in nanocomposite exchange-coupled magnets, indicating complex magnetic interaction between these two magnetic particles. As a result, a small increase in remanence and energy product are observed in hybrid-bonded Nd-Fe-B/Sm 2 Co 17 magnets with 10% mass fraction of Sm 2 Co 17.

Structural Features of Molecular-Colloidal Solutions of C60Fullerenes in Water by Small-Angle Neutron Scattering

Langmuir ◽  
2004 ◽  
Vol 20 (11) ◽  
pp. 4363-4368 ◽  
Author(s):  
M. V. Avdeev ◽  
A. A. Khokhryakov ◽  
T. V. Tropin ◽  
G. V. Andrievsky ◽  
V. K. Klochkov ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Structural Features ◽  
Colloidal Solutions

Nanoferrites Ni-Zn Silanized with 3-Aminopropyltrimethoxysilane Using the Reflux Method

2014 ◽  
Vol 805 ◽  
pp. 94-99 ◽  
Author(s):  
P.T.A. Santos ◽  
Joelda Dantas ◽  
P.M.A.G. Araújo ◽  
P.T.A. Santos ◽  
A.C.F.M. Costa
Keyword(s):  
Magnetic Particles ◽  
Single Phase ◽  
Magnetic Behavior ◽  
Biological Applications ◽  
Inverse Spinel ◽  
Magnetic Attraction ◽  
Structure Morphology ◽  
Zn Ferrite ◽  
Before And After ◽  
Diffraction Peaks

In this paper we propose nanoferrites Ni-Zn silanization with 3-aminopropyltrimethoxysilane using the method of reflux and evaluate the effect of silanization on the structure, morphology and magnetism of the magnetic nanoparticles aimed at biological applications. The samples as synthesized and after silanization were characterized by XRD, FTIR, SEM and testing magnetic attraction. The results indicated a single phase inverse spinel Ni-Zn ferrite, high intensity of diffraction peaks and a high basal width of all reflections observed, indicating that the samples are crystalline, and formation of nanoparticles. Morphologically, for nanoferrites Ni-Zn synthesized observed formation of large agglomerates in the form of spongy blocks of frail and after silanization was observed with respect dense pellets, indicating that most particles were rigidly connected by the presence of the agent silane. The characteristic bands of the spinel were observed for the Ni-Zn nanoferrites before and after silanization, and also observed the characteristic bands of silane in confirming the ferrites silanized functionalization of ferrites with the silane agent. Nanoparticles ferrite as synthesized and after silanized were strongly attracted by the presence of a magnet, immediately after the presence thereof indicating that the silane is effective is not interfere with the magnetic particles, maintaining the same magnetic behavior.

scholarly journals Impact of harmonic distortion on the supraharmonic emission of pulsewidth modulated single-phase power electronic devices

2021 ◽  
Vol 19 ◽  
pp. 577-582
Author(s):  
E. Kaufhold ◽  
◽  
J. Meyer ◽  
P. Schegner
Keyword(s):  
Single Phase ◽  
Electronic Devices ◽  
Harmonic Distortion ◽  
Power Electronic ◽  
Frequency Range ◽  
Pulse Width Modulated ◽  
Current State ◽  
Photovoltaic Applications ◽  
Frequency Coupling ◽  
Single Phase Inverter

This study demonstrates the frequency coupling in pulse width modulated (PWM) single-phase converters and inverters. As current state of the art, the harmonic frequency range, e.g. from fundamental frequency up to 2 kHz, is typically assessed separately from the so-called supraharmonic frequency range, i.e. above 2 kHz up to 150 kHz. The frequency coupling between the harmonic and supraharmonic frequency range has not been thoroughly studied and is currently often neglected in the design process as well as for the analysis of the emission of power electronic devices. The aim of this study is to analyse the behaviour of the frequency coupling between the harmonic and the supraharmonic range. In addition, laboratory measurements of a commercially available single-phase inverter for photovoltaic applications are shown to verify the findings.

scholarly journals Experimental investigation of single-phase microjet cooling of microelectronics

2015 ◽  
Vol 36 (3) ◽  
pp. 139-147 ◽  
Author(s):  
Artur Rusowicz ◽  
Maciej Leszczyński ◽  
Andrzej Grzebielec ◽  
Rafał Laskowski
Keyword(s):  
Heat Flux ◽  
Experimental Investigation ◽  
Integrated Circuit ◽  
Single Phase ◽  
Electronic Devices ◽  
Elementary Level ◽  
Clock Speed ◽  
Logic State ◽  
Microelectronic Components

Abstract Development of electronics, which aims to improve the functionality of electronic devices, aims at increasing the packing of transistors in a chip and boosting clock speed (the number of elementary operations per second). While pursuing this objective, one encounters the growing problem of thermal nature. Each switching of the logic state at the elementary level of an integrated circuit is associated with the generation of heat. Due to a large number of transistors and high clock speeds, higher heat flux is emitted by the microprocessor to a level where the component needs to be intensively cooled, or otherwise it will become overheated. This paper presents the cooling of microelectronic components using microjets.

Nanoscale Structural Features of Ultra-fine Zirconia Powders Obtained Via Precipitation-hydrothermal Treatment Route

2005 ◽  
Vol 878 ◽  
Author(s):  
Vladislav A. Sadykov ◽  
Vladimir I. Zaikovskii ◽  
Dmitrii A. Zyuzin ◽  
Ella M. Moroz ◽  
Elena B. Burgina ◽  
...  
Keyword(s):  
Hydrothermal Treatment ◽  
Single Phase ◽  
Fine Particles ◽  
Structural Features ◽  
Extended Defects ◽  
X Ray Diffraction ◽  
Xrd Patterns ◽  
Symmetric Structures ◽  
Zirconia Powders ◽  
Hydrated Zirconia

AbstractGenesis of the structure of zirconia fine particles prepared by precipitation of amorphous hydrated zirconia by ammonia from the ZrO(NO3)2 solution followed by a mild hydrothermal treatment (HTT) of precipitate, washing and calcination under air up to 1000 °C has been studied by HRTEM, X-ray diffraction, Raman and FTIRS. HTT rearranges the structure of amorphous zirconia, which helps to obtain nearly single-phase monoclinic nanozirconia (particle size 5-15 nm) after a mild calcination at 500 °C. Dehydroxilation and sintering of these nanoparticles at higher (600-650 °C) temperatures generate polysynthetic (001) twins. Modeling revealed that reappearance of the (111) “cubic” reflex in XRD patterns of samples calcined at 600-650 °C can be due to these extended defects. In their vicinity, the seven-fold Zr-O coordination sphere is retained, while packing of ZrO7 polyhedra is varied towards more symmetric structures, thus causing disappearance of the Raman spectra.

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