Influence of a transverse static magnetic field on the magnetic hyperthermia properties and high-frequency hysteresis loops of ferromagnetic FeCo nanoparticles

The influence of a transverse static magnetic field on the magnetic hyperthermia properties is studied on a system of large-losses ferromagnetic FeCo nanoparticles. The simultaneous measurement of the high-frequency hysteresis loops and of the temperature rise provides an interesting insight into the losses and heating mechanisms. A static magnetic field of only 40 mT is enough to cancel the heating properties of the nanoparticles, a result reproduced using numerical simulations of hysteresis loops. These results cast doubt on the possibility to perform someday magnetic hyperthermia inside a magnetic resonance imaging setup.Comment: 6 pages, 3 figure

Environmentally Responsive Core/Shell Particles via Electrohydrodynamic Co-Jetting of Fully Miscible Polymer Solutions

Herein it is demonstrated that electrohydrodynamic co-jetting is not limited to Janus-type particles, but can also be used for the preparation of core/shell particles. Using side-by-side flow of miscible polymer solutions, electrohydrodynamic co-jetting offers an elegant and scalable route towards preparation of core/shell particles with otherwise difficult-to-prepare particle architectures, including particles with hydrophilic shell and core. Throughout this study, electrohydrodynamic co-jetting of aqueous solutions consisting of a mixture of PAAm-co-AA and PAA is used, and a range of different types of particles with distinct compartments are observed. Transition from Janus particles to core/shell particles appears to be caused by changes in the relative conductivity of the two jetting solutions. After crosslinking, the core/shell particles are stable in aqueous solution and exhibit reproducible swelling behavior while maintaining the original core/shell geometry. In addition, the pH-responsiveness of the particles is demonstrated by repeatedly switching the environmental pH between 1.3 and 12. Moreover, the core/shell particles show surprising uptake selectivity. For instance, a 450% increase in uptake of 6-carboxyfluorescein over rhodamine B base is found.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/61234/1/1756_ftp.pd

Examination of Indium Triphospholyls as Precursors for Nanoparticle Synthesis

The synthesis and characterization of the new compounds K(P3C2R2) [R=Ad (2), sBu (3)] and In(P3C2R2) [R=Ad (4), Mes (5)] are described. Further, the synthesis of indium nanoparticles via a single‐source precursor approach using In(1,2,4‐P3C2tBu2) (1) as precursor is reported. These nanoparticles were characterized by TEM, HRTEM, EDX, XRD, NMR, and optical spectroscopy. New compounds of the type M(1,2,4‐P3C2R2) (M=K, In, R=Ad, sBu, Mes) were synthesized, characterized, and examined in view of their use as precursors for indium‐based nanoparticles

Transformation of β-Ni(OH)2to NiO nano-sheets via surface nanocrystalline zirconia coating: Shape and size retention

Shape and size of the synthesized NiO nano-sheets were retained during transformation of sheet-like β-Ni(OH)2to NiO at elevated temperatures via nano-sized zirconia coating on the surface of β-Ni(OH)2. The average grain size was 6.42 nm after 600 °C treatment and slightly increased to 10 nm after 1000 °C treatment, showing effective sintering retardation between NiO nano-sheets. The excellent thermal stability revealed potential application at elevated temperatures, especially for high temperature catalysts and solid-state electrochemical devices

Stoichiometry-controlled FeP nanoparticles synthesized from a single source precursor

Phase-pure FeP nanoparticles (NPs) have been synthesized through low temperature thermolysis of the single source precursor [(CO)4Fe(PH3)]. Examination of the mechanism demonstrates the central role of the labile CO ligands and the weak P–H bonds to yield stoichiometry controlled FeP materials

Far-infrared to millimeter astrophysical dust emission I: A model based on physical properties of amorphous solids

We propose a new description of astronomical dust emission in the spectral region from the Far-Infrared to millimeter wavelengths. Unlike previous classical models, this description explicitly incorporates the effect of the disordered internal structure of amorphous dust grains. The model is based on results from solid state physics, used to interpret laboratory data. The model takes into account the effect of absorption by Disordered Charge Distribution, as well as the effect of absorption by localized Two Level Systems. We review constraints on the various free parameters of the model from theory and laboratory experimental data. We show that, for realistic values of the free parameters, the shape of the emission spectrum will exhibit very broad structures which shape will change with the temperature of dust grains in a non trivial way. The spectral shape also depends upon the parameters describing the internal structure of the grains. This opens new perspectives as to identifying the nature of astronomical dust from the observed shape of the FIR/mm emission spectrum. A companion paper will provide an explicit comparison of the model with astronomical data.Comment: accepted in A&A, 21 pages, 9 figure

Délimiter, occuper ou transmettre un terrain en pays kanak : l’exemple d’Ouvéa, ancienne ‘réserve indigène’

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Délimiter, occuper ou transmettre un terrain en pays kanak : l’exemple d’Ouvéa, ancienne « réserve indigène »

1. Introduction Deux ans après la prise de possession de la Nouvelle-Calédonie par l’État français en 1853, celui-ci s’approprie l’intégralité de ce territoire sur lequel vivaient jusque-là les Kanaks. Leurs terres deviennent ainsi « propriété de l’État français », lequel les destine à une population européenne nouvellement arrivée (militaires, bagnards ou colons). Le système foncier constituant un aspect central de « la coutume » kanake, les spoliations foncières ont alors des réperc..

The category of "probable class" to go beyond a Kanak/non- Kanak dichotomy

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