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Magnetic Properties Of (Γ-Fe₂O₃)₈₀Ag₂₀ Nanocomposites Prepared In Reverse Micelles, Joan A. Wiemann, Jianbiao Dai, Jinke Tang, Gary J. Long, Leonard Spinu Oct 2014

Magnetic Properties Of (Γ-Fe₂O₃)₈₀Ag₂₀ Nanocomposites Prepared In Reverse Micelles, Joan A. Wiemann, Jianbiao Dai, Jinke Tang, Gary J. Long, Leonard Spinu

Jinke Tang

The magnetic properties of nanoparticles of gamma-Fe2O3 prepared by reverse micelles have been studied by dc magnetization, transverse ac susceptibility, and Mössbauer spectroscopy. The nanoparticles of gamma-Fe2O3 in the nanocomposite (gamma-Fe2O3)80Ag20 exhibit superparamagnetic behavior. The blocking temperatures determined by the three methods indicate the superparamagnetic nature of (gamma-Fe2O3)80Ag20 above 70-80 K and show correlation with measuring time. The average particle diameter obtained by transmission electron microscopy of the gamma-Fe2O3 particles is ~10 nm and that of the Ag particles is ~20 nm. The average particle size determined from the magnetic analyses for the gamma-Fe2O3 particles is ~12 nm. Mössbauer spectra …


Magnetic Interaction Reversal In Watermelon Nanostructured Cr-Doped Fe Nanoclusters, Maninder Kaur, Qilin Dai, Mark Bowden, Mark H. Engelhard, Yaqiao Wu, Jinke Tang, You Qiang Oct 2014

Magnetic Interaction Reversal In Watermelon Nanostructured Cr-Doped Fe Nanoclusters, Maninder Kaur, Qilin Dai, Mark Bowden, Mark H. Engelhard, Yaqiao Wu, Jinke Tang, You Qiang

Jinke Tang

Cr-doped core-shell Fe/Fe-oxide nanoclusters (NCs) were synthesized at varied atomic percentages of Cr from 0 at. % to 8 at. %. The low concentrations of Cr (%) were selected in order to inhibit the complete conversion of the Fe-oxide shell to Cr2O3 and the Fe core to FeCr alloy. The magnetic interaction in Fe/Fe-oxide NCs (~25 nm) can be controlled by antiferromagnetic Cr-dopant. We report the origin of σ-FeCr phase at very low Cr concentration (2 at. %) unlike in previous studies, and the interaction reversal from dipolar to exchange interaction in watermelon-like Cr-doped core-shell NCs.


Ultra-Small Fluorescent Inorganic Nanoparticles For Bioimaging, Zhen Li, Qiao Sun, Yian Zhu, Bien Tan, Zhi Ping Xu, S X. Dou Oct 2014

Ultra-Small Fluorescent Inorganic Nanoparticles For Bioimaging, Zhen Li, Qiao Sun, Yian Zhu, Bien Tan, Zhi Ping Xu, S X. Dou

Shi Xue Dou

The novel optical, electrical, and magnetic properties of ultra-small inorganic nanoparticles make them very attractive in diverse applications in the fields of health, clean and renewable energy, and environmental sustainability. This article comprehensively summarizes state-of-the-art fluorescence imaging using ultra-small nanoparticles as probes, including quantum dots, metal nanoclusters, carbon nanomaterials, up-conversion, and silicon nanomaterials.


Platinum Dendritic Nanoparticles With Magnetic Behavior, Wenxian Li, Ziqi Sun, Dongliang Tian, Ivan P. Nevirkovets, S X. Dou Oct 2014

Platinum Dendritic Nanoparticles With Magnetic Behavior, Wenxian Li, Ziqi Sun, Dongliang Tian, Ivan P. Nevirkovets, S X. Dou

Shi Xue Dou

Magnetic nanoparticles have attracted increasing attention for biomedical applications in magnetic resonance imaging, high frequency magnetic field hyperthermia therapies, and magnetic-field-gradient-targeted drug delivery. In this study, three-dimensional (3D) platinum nanostructures with large surface area that features magnetic behavior have been demonstrated. The well-developed 3D nanodendrites consist of plentiful interconnected nano-arms ∼4 nm in size. The magnetic behavior of the 3D dendritic Pt nanoparticles is contributed by the localization of surface electrons due to strongly bonded oxygen/Pluronic F127 and the local magnetic moment induced by oxygen vacancies on the neighboring Pt and O atoms. The magnetization of the nanoparticles exhibits a …


Enhancing Superconducting Properties Of Mgb2 Pellets By Addition Of Amorphous Magnetic Ni-Co-B Nanoparticles, Mislav Mustapic, Josip Horvat, Md Shahriar Hossain, Zeljko Skoko, S X. Dou Apr 2014

Enhancing Superconducting Properties Of Mgb2 Pellets By Addition Of Amorphous Magnetic Ni-Co-B Nanoparticles, Mislav Mustapic, Josip Horvat, Md Shahriar Hossain, Zeljko Skoko, S X. Dou

Josip Horvat

Amorphous magnetic Ni-Co-B nanoparticles with an average size of 5 nm were added to precursor powders of MgB2 superconductor. The preparation procedure for MgB2 pellets was optimized for obtaining the best critical current density (Jc) at elevated magnetic fields. Addition of Ni-Co-B decreases the Jc for heat treatment of precursor powders at 650 ° C. Heat treatments at 770 ° C and higher improve Jc at 20 and 5 K. This improvement occurs at both temperatures through the increase of the effective connectivity between MgB2 crystals. Vortex pinning was enhanced at 5 K, but not at 20 K. Ni-Co-B nanoparticles …


Magnetism Of Zn-Doped Sno2: Role Of Surfaces, Pushpa Raghani, Balaji Ramanujam Mar 2014

Magnetism Of Zn-Doped Sno2: Role Of Surfaces, Pushpa Raghani, Balaji Ramanujam

Pushpa Raghani

Surface effects on the magnetization of Zn-doped SnO2 are investigated using first principles method. Magnetic behavior of Zn-doped bulk and highest and lowest energy surfaces—(001) and (110), respectively, are investigated in presence and absence of other intrinsic defects. The Zn-doped (110) and (001) surfaces of SnO2 show appreciable increase in the magnetic moment (MM) compared to Zn-doped bulk SnO2. Formation energies of Zn defects on both the surfaces are found to be lower than those in bulk SnO2. Zn doping favors the formation of oxygen vacancies. The density of states analysis on the Zn-doped (110) surface reveals that the spin …


Enhancing Superconducting Properties Of Mgb2 Pellets By Addition Of Amorphous Magnetic Ni-Co-B Nanoparticles, Mislav Mustapic, Josip Horvat, Md Shahriar Hossain, Zeljko Skoko, S X. Dou Mar 2014

Enhancing Superconducting Properties Of Mgb2 Pellets By Addition Of Amorphous Magnetic Ni-Co-B Nanoparticles, Mislav Mustapic, Josip Horvat, Md Shahriar Hossain, Zeljko Skoko, S X. Dou

Shi Xue Dou

Amorphous magnetic Ni-Co-B nanoparticles with an average size of 5 nm were added to precursor powders of MgB2 superconductor. The preparation procedure for MgB2 pellets was optimized for obtaining the best critical current density (Jc) at elevated magnetic fields. Addition of Ni-Co-B decreases the Jc for heat treatment of precursor powders at 650 ° C. Heat treatments at 770 ° C and higher improve Jc at 20 and 5 K. This improvement occurs at both temperatures through the increase of the effective connectivity between MgB2 crystals. Vortex pinning was enhanced at 5 K, but not at 20 K. Ni-Co-B nanoparticles …


Cerium Oxide Nanoparticles: Influence Of The High-Z Component Revealed On Radioresistant 9l Cell Survival Under X-Ray Irradiation, Adam Briggs, Stephanie Corde, Sianne Oktaria, Ryan Brown, Anatoly B. Rosenfeld, Michael Lerch, Konstantin Konstantinov, Moeava Tehei Feb 2014

Cerium Oxide Nanoparticles: Influence Of The High-Z Component Revealed On Radioresistant 9l Cell Survival Under X-Ray Irradiation, Adam Briggs, Stephanie Corde, Sianne Oktaria, Ryan Brown, Anatoly B. Rosenfeld, Michael Lerch, Konstantin Konstantinov, Moeava Tehei

Stéphanie Corde

This article pioneers a study into the influence of the high-Z component of nanoparticles on the efficacy of radioprotection some nanoparticles offer to exposed cells irradiated with X-rays. We reveal a significant decrease in the radioprotection efficacy for cells exposed to CeO2 nanoparticles and irradiated with 10 MV and 150 kVp X-rays. In addition, analysis of the 150 kVp survival curve data indicates a change in radiation quality, becoming more lethal for irradiated cells exposed to CeO2 nanoparticles. We attribute the change in efficacy to an increase in high linear energy transfer Auger electron production at 150 kVp which counterbalances …


Nanomaterial-Mediated Biosensors For Monitoring Glucose, Eric S. Mclamore, Masashige Taguchi, Andre Ptitsyn, Jonathan C. Claussen Jan 2014

Nanomaterial-Mediated Biosensors For Monitoring Glucose, Eric S. Mclamore, Masashige Taguchi, Andre Ptitsyn, Jonathan C. Claussen

Jonathan C. Claussen

Real-time monitoring of physiological glucose transport is crucial for gaining new understanding of diabetes. Many techniques and equipment currently exist for measuring glucose, but these techniques are limited by complexity of the measurement, requirement of bulky equipment, and low temporal/spatial resolution. The development of various types of biosensors (eg, electrochemical, optical sensors) for laboratory and/or clinical applications will provide new insights into the cause(s) and possible treatments of diabetes. State-of-the-art biosensors are improved by incorporating catalytic nanomaterials such as carbon nanotubes, graphene, electrospun nanofibers, and quantum dots. These nanomaterials greatly enhance biosensor performance, namely sensitivity, response time, and limit of …


Characterization Of Airborne Particles Generated From Metal Active Gas Welding Processes, João F. Gomes Dec 2013

Characterization Of Airborne Particles Generated From Metal Active Gas Welding Processes, João F. Gomes

João F Gomes

No abstract provided.


Emission Of Nanoparticles During Friction Stir Welding (Fsw) Of Aluminium Alloys, João F. Gomes Dec 2013

Emission Of Nanoparticles During Friction Stir Welding (Fsw) Of Aluminium Alloys, João F. Gomes

João F Gomes

No abstract provided.


The Effect Of Metal Transfer Modes And Shielding Gas Composition On The Emission Of Ultrafine Particles In Mag Steel Welding, João F. Gomes Dec 2013

The Effect Of Metal Transfer Modes And Shielding Gas Composition On The Emission Of Ultrafine Particles In Mag Steel Welding, João F. Gomes

João F Gomes

No abstract provided.


Assessment And Control Of Nanoparticles Exposure In Welding Operations By Use Of A Control Banding Tool (Doi: 10.1016/J.Jclepro.2014.11.010), João F. Gomes Dec 2013

Assessment And Control Of Nanoparticles Exposure In Welding Operations By Use Of A Control Banding Tool (Doi: 10.1016/J.Jclepro.2014.11.010), João F. Gomes

João F Gomes

No abstract provided.