Hybrid porous magnetic bentonite-chitosan beads for selective removal of radioactive cesium in water.

SiO2 amorphous nanopowder (NP) is produced with the specific surface area of 154 m2/g by means of evaporation by a pulsed electron beam aimed at Aerosil 90 pyrogenic amorphous NP (90 m2/g) as a target. SiO2 NP nanoparticles showed improved magnetic, thermal, and optical properties in comparison to Aerosil 90 NP. Possible reasons of emergence of d0 ferromagnetism at the room temperature in SiO2 amorphous NP are discussed. Photoluminescent and cathode luminescent properties of the SiO2 NP were investigated.

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Properties of Silicon Dioxide Amorphous Nanopowder Produced by Pulsed Electron Beam Evaporation

An amorphous SiO2 nanopowder with a specific surface area of 154 m2/g has been prepared using pulsed electron beam evaporation of a target from a pyrogenic amorphous Aerosil 90 nanopowder (90 m2/g). It has been found that SiO2 nanoparticles exhibit improved magnetic, thermal, and optical properties as compared to the properties of particles of the Aerosil 90 nanopowder. Possible factors responsible for the appearance of ferromagnetism at room temperature in the amorphous SiO2 nanopowder formed upon electron beam evaporation have been discussed. The photoluminescence and cathodoluminescence properties of the SiO2 nanopowder have been investigated.

Properties of an amorphous silicon dioxide nanopowder prepared by pulsed electron beam evaporation

Three-phase (corundum + δ phase + amorphous phase) amorphous–nanocrystalline powders of pure and carbon-doped Al2O3 (x
 C = 1.07–6.6 wt %) have been produced by pulsed electron beam evaporation in vacuum. The corundum hexagonal nanocrystals in the Al2O3–C nanopowder (x
 C = 1.07 wt %) had sizes about 5 nm. The carbon solubility boundary in the Al2O3 lattice was lower than 1.07 wt % C. The dependence of the form of the cathode-luminescence spectra and the phase compositions of the prepared Al2O3 and Al2O3–C nanopowders has been found. The absence of R lines of Cr3+ ions in photoluminescence spectra of doped nonopowders has been detected. All the nanopowders of the pure and C-doped Al2O3 were ferromagnets at room temperature with the maximum magnetization of ~0.12 emu/g at x
 C = 6.6 wt %.

Structural and magnetic–luminescent properties of carbon-doped aluminum oxide

We use solution immersion method to prepare the SiO2 network structure. A single-layer PS sphere template was immersed in SiO2 precursor solution for a certain period of time. Filter paper was used to absorb the residual liquid, and then the PS nanospheres were removed by high temperature-annealing to form SiO2 network structure. The Si honeycomb structure was formed on the SiO2 network structure by chemical vapor deposition method. The longer growth time caused the smaller sizes of the Si apertures and produced various quantum size effects. When the growth time is 15 min, the thermal conductivity of the sample is the lowest. The heat conduction behavior of the 15 min sample is similar to that of a phonon crystal due to the aperture size of the sample is almost the same as the mean free path of phonons. Scattering at the interface of the isolated honeycomb microstructures also contributed to the low thermal conductivity. The position and number of the reflection peak of the sample can be controlled by the deposition time. The luminescence properties of the samples are greatly influenced by the surface topography.

Fabrication and optical properties of the Si honeycomb structure via colloidal monolayer template

A new hole-bridge structure based on a SiO2 nanoarray and its ferromagnetism

The invention discloses a Ge-SiN composite film material with room-temperature ferromagnetic property The chemical formula of the Ge-SiN composite film material is (Gex-(SiN)y)z, wherein x, y and z represents the thickness of a Ge layer, the thickness of an SiN layer and the time of circular sputtering of Ge and SiN films, x is more than or equal to 3nm and less than or equal to 10nm, y is more than or equal to 4nm and less than or equal to 16nm and z is more than or equal to 3 and less than or equal to 16 (z is an integer) A preparation method is as follows: the principle of the quantum confinement effect is adopted for preparing multilayer films so that the material is magnetic, ie, Ge and SiN is sputtered circularly by radio frequency The preparation method disclosed by invention is compatible to the matured semiconductor process, and simple in preparation process The composite film material has the potential application in the aspects such as novel magnetic storages and miniature spinning electronic devices

Ge-SiN composite film material with room-temperature ferromagnetic property and preparation method of composite fim material

The invention discloses a nanometer silicon dioxide microsphere material with room temperature ferromagnetism. The nanometer silicon dioxide microsphere material with the room temperature ferromagnetism is produced by depositing silicon dioxide microspheres on a silicon substrate in order, wherein the concentration of silicon dioxide microspheres in a precursor solution used for depositing is less than or equal to 7.6mg/ml, and samples present different levels of room temperature ferromagnetism. A preparing method of the nanometer silicon dioxide microsphere material includes depositing a series of silicon dioxide microsphere layers with different thicknesses on the silicon substrate by using a vertical deposition method. Experiments confirm that the samples of the silicon dioxide microspheres which have appropriate thicknesses have magnetism, and when the concentration of the silicon dioxide microspheres in the precursor solution is 0.76mg/ml, saturation magnetization intensity of the samples reaches the strongest, and residual magnetization intensity and coercive force also reach the strongest. Orbital magnetic torque formed due to the fact that charge transfers among the silicon dioxide microspheres and the silicon substrate is the basic reason of generating the magnetism. The nanometer silicon dioxide microsphere material with the room temperature ferromagnetism and the preparing method are abundant in raw material and simple in preparation technology. The magnetic nanometer silicon dioxide microspheres have potential applications in aspects of catalysis, magnetism development, biomedicine and the like.

Nanometer silicon dioxide microsphere material with room temperature ferromagnetism and preparing method thereof

The invention discloses a composite film material with the chemical formula of C-Al2O3-delta and room-temperature ferromagnetism. In the formula, the percent by volume of C is smaller than or equal to 10 vol%. Relative to Al2O3, Al2O3-delta is an alumina film material under the anaerobic condition. The preparation method is as follows: using a radio frequency sputtering method to prepare a series of C-Al2O3-delta composite films with different contents of C. The Al2O3 matrix material is free from magnetism per se, while the composite film prepared by the interface limitation effect adopting the substrates of C and Al2O3-delta has the effect of magnetism. The composite film material is compatible with the mature semiconductor technology, so that the preparation technology is simple, and the magnetic C-Al2O3-delta composite film material can be potentially applied to novel magnetic memories and mini-spintronic devices and the like.

Liu Xiumin

Papers

A new hole-bridge structure based on a SiO2 nanoarray and its ferromagnetism

Ge-SiN composite film material with room-temperature ferromagnetic property and preparation method of composite fim material

Nanometer silicon dioxide microsphere material with room temperature ferromagnetism and preparing method thereof

C-Al2O3-delta composite film material with room-temperature ferromagnetism and preparation method thereof