Synthesis of suspensions nanosize particles Fe3O4 was carried out in bulk aqueous solutions without the presence surfactants. The nanoparticles were oxidized to γ-Fe2O3 by direct aeration suspension at 100 °C. shape and size distribution crystallinity assessed transmission electron microscopy selected area diffraction. Very uniform stable colloidal water could be synthesized. Oxidation system leads much larger than Fe3O4.

ADVERTISEMENT RETURN TO ISSUEPREVAddition/CorrectionSynthesis and Characterization of Nanometer-Size Fe3O4 γ-Fe2O3 ParticlesYoung Soo Kang, Subhash Risbud, John F. Rabolt, Pieter StroeveCite this: Chem. Mater. 1998, 10, 6, 1733Publication Date (Web):May 28, 1998Publication History Published online28 May 1998Published inissue 1 June 1998https://pubs.acs.org/doi/10.1021/cm970904shttps://doi.org/10.1021/cm970904scorrectionACS PublicationsCopyright © 1998 American Chemical Society. This...

Using in situ Raman scattering a confocal microscopy setup, we have observed changes the network structure of fused silica after modifying regions inside glass with tightly focused 800-nm 130-fs laser pulses at fluences 5-200 J cm(-2). The spectra show large increase peaks 490 and 605cm(-1), owing to 4- 3-membered ring structures network, indicating that densification occurs exposure femtosecond pulses. results are consistent formation localized plasma by pulse subsequent microexplosion glass.

We report a novel method for the synthesis of stable, OH free zinc oxide quantum dots, using an electrochemical route. The optical properties these dots were studied at room temperature, by taking absorption and luminescence spectra. band gap is predominant in ZnO synthesized present technique, while green defect induced luminescence, typical ZnO, strongly quenched. role defects photoluminescence emission discussed.

The structures of roller‐quenched SiO 2 ‐Al O 3 glasses containing 10 to 50 wt% Al were investigated by TEM and high‐resolution 27 29 Si magic angle sample spinning nuclear magnetic resonance (MASS‐NMR) spectroscopy. chemical shifts observed in the NMR spectra these phase‐separated (on scale) provide evidence, for existence all three (4‐, 5‐, 6‐jold) Al‐coordination units presence A1 both Si‐rich Si‐poor phases.

Thin films of topological insulator Bi${}_{2}$Se${}_{3}$ were deposited directly on insulating ferromagnetic EuS. Unusual negative magnetoresistance was observed near the zero field below Curie temperature ${T}_{C}$, resembling weak localization effect; whereas usual positive recovered above ${T}_{C}$. Such only for layers thinner than $t\ensuremath{\sim}4$ nm, when its top and bottom surfaces are coupled. These results provide evidence a proximity effect between an ferromagnet, laying...

We report on the response of glass to focused femtosecond (fs) laser pulses during waveguide fabrication in a commercial sodium aluminum phosphate (Schott IOG-1). Single-pass longitudinal translation IOG-1 with respect beam at rate 20 μm/s and pulse energies 3.5 μJ results formation two waveguides located opposite sides laser-exposed region, which itself does not guide light. This behavior is different from that more widely studied silica system. The precise location depends relative tilt fs...

Nanoparticles of indium oxide, a transparent conducting oxide with band gap close to GaN, were synthesized by pulsed laser ablation pure metal target. X-ray diffraction and transmission electron microscopy confirmed that nanocrystalline particles mean diameter 6.6 nm cubic crystal structure formed. Photoluminescence spectroscopy shows strong emission peak at 3.78 eV weak size dependence.

Lead sulfide, PbS, nanoparticles have been synthesized using a number of surface capping agents including poly(vinyl-alcohol) (PVA), poly(vinyl-pyrrolidone) PVP, gelatin, DNA, polystyrene (PS), and poly(methyl-methacrylate) (PMMA). The electronic absorption spectra particle shapes found to depend on the molecules used. An excitonic feature at 580 nm was observed for with PVA while no such PS or PMMA. A weak gelatin. shape varied from cubic, needle spherical as controlled by agents. For...

ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTReverse Micelle Synthesis and Characterization of ZnSe NanoparticlesForest T. Quinlan, Joerg Kuther, Wolfgang Tremel, Knoll, Subhash Risbud, Pieter StroeveView Author Information Center on Polymer Interfaces Macromolecular Assemblies (CPIMA), Department Chemical Engineering Materials Science, University California, Davis, California 95616, Institut fur Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universitat, Mainz D-55099, Germany,...

The sequence of stages during precipitation semiconductor (e.g., CdS, CdSe) clusters from supersaturated glasses exhibiting quantum-confinement effects was investigated. rate formation nanometer-size ‘‘quantum dots’’ distributed in a continuous glass matrix is critically determined by the time and temperature heat treatment given to quenched glasses. entire process analyzed terms several decomposition stages: nucleation, normal growth, coalescence quantum dots, devitrification itself....

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRaman spectroscopy of calcium phosphate glasses with varying oxide modifier concentrationsJeanne E. Pemberton, Lida Latifzadeh, Joseph P. Fletcher, and Subhash H. RisbudCite this: Chem. Mater. 1991, 3, 1, 195–200Publication Date (Print):January 1991Publication History Published online1 May 2002Published inissue 1 January 1991https://pubs.acs.org/doi/10.1021/cm00013a039https://doi.org/10.1021/cm00013a039research-articleACS PublicationsRequest reuse...

Abstract High-purity aluminium nitride (AlN) powders of submicron size were consolidated to almost theoretical density in minutes at 1800°C using a plasma-activated sintering (PAS) process. The structure and microchemistry grain boundaries this polycrystalline material (average size, about 0.43 μm), sintered without additives commonly used the densification ceramics, was examined by high-resolution electron microscopy high-spatial-resolution electron-energy-loss spectroscopy (EELS). 'clean'...

In combination of direct phase retrieval coherent x-ray diffraction patterns with a novel tomographic reconstruction algorithm, we, for the first time, carried out quantitative 3D imaging heat-treated GaN particle each voxel corresponding to 17 x nm3. We observed platelet structure and formation small islands on surface platelets, successfully captured internal GaN-Ga2O3 core shell in three dimensions. This work opens door nondestructive morphology wide range materials at nanometer scale...

Thermodynamic data on activities, activity coefficients, and free energies of mixing in SiO 2 ‐Al O 3 solutions were calculated from the phase diagram. Positive deviations ideal thermodynamic suggest a tendency for liquid immiscibility both ‐ Al ‐rich compositions. The used to estimate regions liquid‐liquid immiscibility. A metastable miscibility gap with consolute temperature ∼1540 ° C at critical composition ∼36 mol% was considered be thermodynamically most probable; extended ∼11 °49 1100...

The missing data problem, i.e., the intensities at center of diffraction patterns cannot be experimentally measured, is currently a major limitation for wider applications coherent microscopy. We report here that, when are confined within centrospeckle, problem can reliably solved. With an improved instrument, we recorded 27 oversampled various orientations from GaN quantum dot nanoparticle and performed quantitative image reconstruction alone. This work in principle clears way single-shot...