scholarly journals Magnetic Nanoparticles with Core Shell: Macroscopic Model and Coercive Field

2010 ◽  
Vol 2010 ◽  
pp. 1-6 ◽  
Author(s):  
O. Hudak ◽  
M. Hudak
Keyword(s):  
Magnetic Properties ◽  
Magnetic Nanoparticles ◽  
Shell Structure ◽  
Coercive Field ◽  
Macroscopic Model ◽  
Core Shell ◽  
Qualitative Explanation ◽  
The Core ◽  
Core Shell Structure ◽  
Nonhomogeneous Structure

There exists nonhomogeneous structure in mechanosynthesized nanoparticles consisting of an ordered core surrounded by the shell. The shell may be structurally and magnetically disordered, or it may be ordered. These nanoparticles are found to be roughly spherical. We formulate the macroscopic model for the description of magnetic properties of nanoparticles with core-shell structure. The case of spheroids oriented in the same direction of polar axes is considered. There exits two coercive fields:HcγandHcψ. They are depending on quantitiesoandx, wherex=V2/(V1−2V2), ando=IF/IS, hereV1is the volume of the nanoparticle, andV2is the volume of the core.IFis the magnetization of the core, andISis the magnetization of the shell. There exists a transition from one type of the coercive field to another, changingxando. We have found qualitative explanation of observed enhancement of coercive field and of itsd-dependence inNiFe2O4nanoparticles.

Characterization of Fe3O4@CS@NMDP magnetic nanoparticles with core–shell structure prepared by chemical cross-linking method

2017 ◽  
Vol 10 (05) ◽  
pp. 1750056 ◽  
Author(s):  
Huiping Shao ◽  
Jiangcong Qi ◽  
Tao Lin ◽  
Yuling Zhou ◽  
Fucheng Yu
Keyword(s):  
Magnetic Nanoparticles ◽  
Shell Structure ◽  
High Performance ◽  
Cross Linking ◽  
Composite Particles ◽  
Core Shell ◽  
The Core ◽  
Targeting Delivery ◽  
Core Shell Structure ◽  
Chemical Cross Linking

The core–shell structure composite magnetic nanoparticles (NPs), Fe3O4@chitosan@nimodipine (Fe3O4@CS@NMDP), were successfully synthesized by a chemical cross-linking method in this paper. NMDP is widely used for cardiovascular and cerebrovascular disease prevention and treatment, while CS is of biocompatibility. The composite particles were characterized by an X-ray diffractometer (XRD), a Fourier transform infrared spectroscopy (FT-IR), a transmission electron microscopy (TEM), a vibrating sample magnetometers (VSM) and a high performance liquid chromatography (HPLC). The results show that the size of the core–shell structure composite particles is ranging from 12[Formula: see text]nm to 20[Formula: see text]nm and the coating thickness of NMDP is about 2[Formula: see text]nm. The saturation magnetization of core–shell composite NPs is 46.7[Formula: see text]emu/g, which indicates a good potential application for treating cancer by magnetic target delivery. The release percentage of the NMDP can reach 57.6% in a short time of 20[Formula: see text]min in the PBS, and to 100% in a time of 60[Formula: see text]min, which indicates the availability of Fe3O4@CS@NMDP composite NPs for targeting delivery treatment.

Controlled Synthesis of Core-Shell Structure SiO2 /NaGdF4:Eu3+ Magnetic and Optical Bifunctional Composite

2014 ◽  
Vol 936 ◽  
pp. 359-363
Author(s):  
Yan Li Wu ◽  
Min Liao ◽  
Hai Xin Ding ◽  
Ru Chun Yang ◽  
Dan Dan Xiong ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Shell Structure ◽  
Photo Luminescence ◽  
Core Shell ◽  
Controlled Synthesis ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Core ◽  
Core Shell Structure ◽  
Shell Composite

The SiO2/NaGdF4:Eu3+ core/shell composite was prepared by a template-mediated method, making monodispersed SiO2 as core and NaGdF4:Eu colloids as shell, the morphology and the core-shell structure of the resulting particles were analyzed by SEM,X-ray diffraction, and the photo-luminescence and magnetic properties of the microspheres were investigated too. The results shows the composite have great potential to be used as homogeneous magnetic/optical bifunctional material.

Fabrication and evaluation of molecularly imprinted magnetic nanoparticles for selective recognition and magnetic separation of lysozyme in human urine

The Analyst ◽  
2018 ◽  
Vol 143 (23) ◽  
pp. 5849-5856 ◽  
Author(s):  
Zulei Zhang ◽  
Hongmei Wang ◽  
Hailong Wang ◽  
Cuichen Wu ◽  
Mengli Li ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetic Nanoparticles ◽  
Magnetic Separation ◽  
Human Urine ◽  
Shell Structure ◽  
Good Stability ◽  
Selective Recognition ◽  
Core Shell ◽  
Molecularly Imprinted ◽  
Core Shell Structure

The Lyz-MMIPs displayed a uniform core–shell structure, favorable magnetic properties, good accessibility, and good stability and had a good affinity and excellent binding selectivity to Lyz.

scholarly journals A SERS Study of Charge Transfer Process in Au Nanorod–MBA@Cu2O Assemblies: Effect of Length to Diameter Ratio of Au Nanorods

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 867
Author(s):  
Lin Guo ◽  
Zhu Mao ◽  
Sila Jin ◽  
Lin Zhu ◽  
Junqi Zhao ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Shell Structure ◽  
Shell Structures ◽  
Core Shell ◽  
Absorption Bands ◽  
Au Nanorods ◽  
The Core ◽  
Band Position ◽  
Surface Enhanced Raman ◽  
Core Shell Structure

Surface-enhanced Raman scattering (SERS) is a powerful tool in charge transfer (CT) process research. By analyzing the relative intensity of the characteristic bands in the bridging molecules, one can obtain detailed information about the CT between two materials. Herein, we synthesized a series of Au nanorods (NRs) with different length-to-diameter ratios (L/Ds) and used these Au NRs to prepare a series of core–shell structures with the same Cu2O thicknesses to form Au NR–4-mercaptobenzoic acid (MBA)@Cu2O core–shell structures. Surface plasmon resonance (SPR) absorption bands were adjusted by tuning the L/Ds of Au NR cores in these assemblies. SERS spectra of the core-shell structure were obtained under 633 and 785 nm laser excitations, and on the basis of the differences in the relative band strengths of these SERS spectra detected with the as-synthesized assemblies, we calculated the CT degree of the core–shell structure. We explored whether the Cu2O conduction band and valence band position and the SPR absorption band position together affect the CT process in the core–shell structure. In this work, we found that the specific surface area of the Au NRs could influence the CT process in Au NR–MBA@Cu2O core–shell structures, which has rarely been discussed before.

Construction of MOFs-Shell Porous Materials and Performance Study in Selective Adsorption and Separation of Benzene Pollutants

2021 ◽  
Author(s):  
Yu Qiao ◽  
Na Lv ◽  
Dong Li ◽  
Hongji Li ◽  
Xiangxin Xue ◽  
...  
Keyword(s):  
Porous Materials ◽  
Shell Structure ◽  
Selective Adsorption ◽  
Core Shell ◽  
Architecture Design ◽  
Performance Study ◽  
The Core ◽  
Core Shell Structure ◽  
And Performance ◽  
Sacrificial Agent

Metastable Cu2O is an attractive material for the architecture design of integrated nanomaterials. In this context, Cu2O was used as the sacrificial agent to form the core-shell structure of Cu2O@HKUST-1...

Preparation of polyacrylamide microspheres with core–shell structure via surface-initiated atom transfer radical polymerization

RSC Advances ◽  
2016 ◽  
Vol 6 (94) ◽  
pp. 91463-91467 ◽  
Author(s):  
Peng Zhang ◽  
Shixun Bai ◽  
Shilan Chen ◽  
Dandan Li ◽  
Zhenfu Jia ◽  
...  
Keyword(s):  
Atom Transfer Radical Polymerization ◽  
Radical Polymerization ◽  
Shell Structure ◽  
Core Shell ◽  
Atom Transfer ◽  
The Core ◽  
Core Shell Structure

Well defined core–shell microspheres were prepared by surface-initiated atom transfer radical polymerization with pre-crosslinked polyacrylamide as the core and non-crosslinked polyacrylamide as the shell.

Microstructure and magnetic properties of SiO2/FeCoNiSi0.25 high-entropy alloy with a core/shell structure

2021 ◽  
Vol 290 ◽  
pp. 129399
Author(s):  
Shaofeng Yang ◽  
Jianan Wen ◽  
Fangyang Zhang ◽  
Jingyi Xie ◽  
Jiao Mo ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Shell Structure ◽  
High Entropy Alloy ◽  
Core Shell ◽  
High Entropy ◽  
Core Shell Structure ◽  
Microstructure And Magnetic Properties

Core–shell stability of nanoparticles plays an important role for overcoming the intestinal mucus and epithelium barrier

2016 ◽  
Vol 4 (35) ◽  
pp. 5831-5841 ◽  
Author(s):  
Min Liu ◽  
Lei Wu ◽  
Xi Zhu ◽  
Wei Shan ◽  
Lian Li ◽  
...  
Keyword(s):  
Shell Structure ◽  
Core Shell ◽  
The Core ◽  
Shell Stability ◽  
Intestinal Mucus ◽  
Core Shell Structure ◽  
The Stability

The stability of the core–shell structure plays an important role in the nanoparticles ability to overcome both the mucus and epithelium absorption barrier.

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