جستجوی مقالات مرتبط با کلیدواژه « magnetization » در نشریات گروه « شیمی »

In this work, we report the green synthesis of cobalt ferrite (CoFe2O4) nanoparticles Ferrofluid by a modified co-precipitation method using Glycyrrhiza glabra (Licorice) roots as a surfactant, which is eco-friendly, non-toxic, and inexpensive. X-Ray diffraction (XRD) analysis confirmed the purity of the spinel CoFe2O4 structure. The average crystallite size, strain and lattice constant were 5 nm, 0.01, and 8.39 Ao, respectively. Fourier transform infrared spectrum (FTIR) results demonstrated an absorption band at a wavenumber of 574 cm-1, indicating the presence of cobalt ferrite nanoparticles. transmission electron microscopy (TEM) images showed that the sample contains well-dispersed and spherical nanoparticles with an average particle size of 12.6 nm. The magnetic properties of the fluid are confirmed from the (M-H) hysteresis curve. The hysteresis curve revealed the ferromagnetic nature of the particles, and the saturation magnetization (MS) is 56.6 emu/g. The rheological properties were studied with a variable magnetic field rheometer. The results showed that the rheological measurements comply with the structural and magnetic properties of the CFO FF by a green modified co-precipitation synthesis G. glabra, which can be used for various medical applications.

Due to the natural bone microstructure, the design and fabrication ofporous ceramic scaffold nanocomposite materials coated with a thin layer of a naturalthe polymer can provide an ideal scaffold for bone tissue engineering. This study aimed tofabricate multi-component porous magnetic scaffolds by freeze-drying (FD) techniqueusing a gelatin polymer layer coated with a gentamicin drug.

Magnetic nanoparticles (MNPs) can be manipulated and controlled byan external magnetic field gradient (EMFG) that is inherent in the magnetic field'spermeability within human tissues. In the present work, unlike the usual ceramic/polymer composite scaffold, the ceramic components, and the magnet were placedtogether in the reaction medium from the beginning, and bioceramics were replacedin the composite polymer network and then coated with a drug-loaded polymer. Toevaluate the morphology of the magnetic scaffold, scanning electron microscopy(SEM) was utilized to evaluate the microstructure and observe the porosity of theporous tissue.

After analyzing the SEM images, the porosity of the scaffolds was measured,which was similar to the normal bone architecture. The addition of gentamicin tothe gelation was investigated to monitor the drug delivery reaction in the biologicalenvironment. The magnetic properties of the sample were evaluated using thehyperthermia test for 15 seconds at the adiabatic conditions. Also, the porosity valueincreased from 55% to 78% with the addition of MNPs to the based matrix.

The results of this study showed that gentamicin-gelatin-coated onporous ceramic-magnet composite scaffolds could be used in bone tissue engineeringand apply for treatment of bone tumors, because of their similarity to the bonestructure with good porosity.

Here we describe a simple and novel electrochemical synthesis for preparation of Mn doped iron oxide nanoparticles (MIOs) and their surface coating with saccharides (i.e. glucose, sucrose and starch). The electrochemical preparation of MIOs samples were carried out in a two-electrode electrochemical set up including graphite anode and stainless steel cathode. The surface coating with saccharide agents was also performed in the same set up and simultaneously with the formation of iron oxide particles on the cathode surface. The fabricated MIOs were specified through FT-IR, FE-SEM, XRD, DSC-TGA, and VSM analyses. The structural data obtained by XRD proved the magnetite (Fe3O4) crystal phase of samples, and FT-IR and TG data showed the Mn doping and saccharide coat on the surface of the deposited MIONs. The FE-SEM observations and EDS data confirmed the particle morphology and magnetite chemical composition as well as Mn ions doping into the MIONs. The superparamagnetic nature and suitable magnetic ability (i.e. high saturation magnetization, negligible remanent magnetization and coercivity) for the fabricated MIONs were also assessed though vibrating sample magnetometer (VSM) results. These characters of the electrosynthesized sample provided their suitability for biomedical applications.

Magnetic nanoparticles (MNPs) are very important systems with potential use in drug delivery systems, ferrofluids, and effluent treatment. In many situations, such as in biomedical applications, it is necessary to cover inorganic magnetic particles with an organic material, such as polymers. A superparamagnetic nanocomposite Fe3O4/poly(maleic anhydride-co-acrylic acid) P(MAH-co-AA) with a core/shell structure was successfully synthesized by a dispersion polymerization route. Iron oxide nanoparticles were used as a core, and P(MAH-co-AA) as a shell was covered on the surface of the Fe3O4 magnetic nanoparticles. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that the Fe3O4/P(MAH-co-AA) magnetic nanocomposite were highly uniform in size and cubic shape with the average size about 17.06 nm. X-ray diffraction confirmed magnetite cores and also indicated that the binding process did not change the phase of Fe3O4. Vibrational sample magnetometer (VSM) revealed the nanoparticles were superparamagnetic and the saturation magnetization was 83.6 and 46.6 emu g-1 for pure Fe3O4 and composite nanoparticles, respectively. Measurements by VSM also showed that the degree of saturation magnetization increased with increasing iron oxide concentration from 1% to 7 wt % of Fe3O4.

In the current investigation, Fe3O4 water-based nanofluids were synthesized to examine the effect of an alternative 3-D external magnetic field on its thermal behavioral pattern. A solvothermal method was used to prepare the magnetite nanoparticles. To characterize the nanoparticles, the study employed transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, vibrating sample magnetometer and zeta-potential experiments. Vibrating sample magnetometer evaluations thoroughly confirmed the super-paramagnetic characteristics of the nanoparticles. Therefore, exposition of the resulting nanofluids to an AC external magnetic field led to the formation of aligned dipoles parallel to the applied field. Afterwards, the net magnetization in the absence of the external field was set to zero. Thermal measurements demonstrated an enhancement of convective heat transfer coefficients, particularly in the case of more diluted samples. The highest value of h was associated with the most diluted sample, where the h value was two times greater than that in the base fluid at V=1.4 V. This was attributed to the augmentation of both the Brownian motions and the viscosity gradients in the centerline of the test section.

Studies of the magnetization of Fe2O3@Pt nanoparticles at room temperature showed that there is superparamagnetic contribution with high saturation magnetization about 12.35(emu/g), and soft ferromagnetic contribution with narrow coercive field about 58(Oe). In this paper we fitted the hystersis loop of sample with Brillouin function that demonstrating existence of superparamagnetic phase. Total angular momentum quantum number J With computations performance, gave consistent value at high level that could be the reason into existence of spin clusters. Upshot theoretically, magnetic susceptibility of this sample was calculated from the Brillouin function at fields less than 1000(Oe) from 0.1 to 400 K to determine the high-temperature susceptibility.