Manganese ferrite, ${\mathrm{MnFe}}_{2}$${\mathrm{O}}_{4}$, fine particles in the size range 5--15 nm have been prepared by an aqueous phase coprecipitation method. The freshly are a metastable state with regard to cation distribution between A and B sites of spinel lattice. Thermomagnetic, differential scanning calorimetry M\"ossbauer spectroscopy show that heat treatment under inert gas 670 K irreversibly changes stable state. Heat samples air 470 both site somewhat and, most importantly,...

The magnetic and morphological properties of fine Fe particles have been studied. Ultrafine were prepared using a vapor deposition technique under an argon atmosphere. pressure was varied from 0.5 to 8 Torr during evaporation, samples with median diameter in the range 50--200 \AA{} obtained having log-normal distribution. dependence on particle size temperature (10 KT300 K) studied superconducting-quantum-interference-device magnetometry M\"ossbauer spectroscopy. Samples below 90 showed...

The ever-growing demand for portable, bendable, twistable, and wearable microelectronics operating in a wide temperature range has stimulated an immense interest the development of solid-state flexible energy storage devices using scalable fabrication technology. Herein, we developed additively manufactured graphene aerosol gel-based all-solid-state micro-supercapacitors (MSCs) via inkjet printing with functioning from −15 to +70 °C exhibiting super-stable reliable electrochemical...

Particle−particle and particle−substrate interactions cause nanocrystals to self-assemble into superlattice structures upon drying from a colloidal suspension on solid surface. Rapid dewetting of volatile solvent, however, can significantly undermine the degree ordering. We demonstrate here that by increasing concentration nonvolatile dodecanethiol ligand, be controlled gold nanocrystal superlattices formed silicon nitride substrates with long range ordering over several microns. Monolayer...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTChemistry of Borohydride Reduction Iron(II) and Iron(III) Ions in Aqueous Nonaqueous Media. Formation Nanoscale Fe, FeB, Fe2B PowdersGeorge N. Glavee, Kenneth J. Klabunde, Christopher M. Sorensen, George C. HadjipanayisCite this: Inorg. Chem. 1995, 34, 1, 28–35Publication Date (Print):January 1995Publication History Published online1 May 2002Published inissue 1 January...

We have determined the Curie temperature ${\mathit{T}}_{\mathit{c}}$ of ferrimagnetic ${\mathrm{MnFe}}_{2}$${\mathrm{O}}_{4}$ nanoscale particles by means direct measurement magnetization. A considerable enhancement in compared to bulk was observed for size range 7.5 24.4 nm. At d=7.5 nm, is 97 K higher than material. The shift well described finite-size-scaling formula...

We describe a synthetic procedure for preparation of large quantities monodisperse thiol-stabilized gold colloids in toluene solution. The method is based on the solvated metal atom dispersion technique (SMAD), which very suitable amounts colloidal solutions, as well sulfide, oxide, and other types dispersed compounds different solvents. A combination two solvents like acetone used colloids. necessity initially carrying out SMAD reaction comes from its high degree solvation particles....

Several ligands, such as alkylthiols, -amines, -silanes, -phosphines, -halides, and simple alkanes, were employed for digestive ripening, a process in which colloidal suspension solvent is refluxed at the boiling temperature presence of surface-active ligand to convert highly polydisperse colloid into nearly monodisperse one. Apart from thiols, are only established digestive-ripening amines, silanes, phosphines found be similarly efficient this purpose. The important steps involved ripening...

Digestive ripening, heating a colloidal suspension at or near the solvent boiling point in presence of surface-active ligand, was applied to polydisperse gold toluene using series alkylthiols, viz., octyl-, decyl-, dodecyl-, and hexadecylthiols. In all instances, digestive ripening significantly reduced average particle size polydispersity. All colloids remain suspended solution above 80 °C, but room temperature tendency form 3D superlattices precipitate increased with declining alkyl chain...

We have used a microemulsion technique to synthesize metallic cobalt particles in the size range 18 44 \AA{} diameter. The are spherical, not aggregated due their surfactant coating, and free of oxide. Magnetic properties such as total moment per particle, blocking temperature, hysteresis all show reasonable dependencies. effects small seen in: (1) anisotropy constant increased markedly particle decreased, (2) magnetic atom Co was enhanced with decreasing by much 30% over bulk value....

Cubic structured CdS, CdSe, and CdTe, II–VI semiconductor nanoparticles have been synthesized using aqueous solution precipitation at room temperature. The ‘‘as-prepared’’ particles a size of about 30 Å. Thermal annealing causes (a) an increase in particle size; (b) structural transition from the cubic to bulk, hexagonal structure for CdS CdSe; (c) no CdTe. unexpected phase small CdSe may be due either metastability or equilibrium surface effect. latter would imply strong correlation between...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTBorohydride reduction of cobalt ions in water. Chemistry leading to nanoscale metal, boride, or borate particlesGeorge N. Glavee, Kenneth J. Klabunde, Christopher M. Sorensen, and George C. HadjipanayisCite this: Langmuir 1993, 9, 1, 162–169Publication Date (Print):January 1993Publication History Published online1 May 2002Published inissue 1 January...

We have measured the density of supercooled water (H2O) in range −33.41≤T≤−5.23 °C. Our samples were held glass capillary tubing with an approximate inside diameter 0.3 mm=300 μ. These prepared by Mossop’s method and could be cooled to their homogeneous nucleation limit before freezing. compare our data other measurements using capillaries demonstrate what appears excess smaller which is inversely proportional diameter. The origins this are unknown, but we show its effect insignificant on...

Dodecanethiol-stabilized gold nanoparticles with similar average size organize into different superlattice structures depending upon the method of preparation nanocrystals. Particles synthesized by inverse micelle technique preferentially assemble face-centered cubic (fcc) long-range translational and orientational ordering. Gold obtained solvated metal atom dispersion (SMAD) behave like “hard” spheres predominantly hexagonal close-packed (hcp) nanocrystal superlattices Different packing...

ADVERTISEMENT RETURN TO ISSUEPREVResearch ArticleNEXTBiocidal Activity of Nanocrystalline Silver Powders and ParticlesAlexander B. Smetana†, Kenneth J. Klabunde*†, George R. Marchin§, Christopher M. Sorensen‡View Author Information Department Chemistry, Kansas State University, 111 Willard Hall, Manhattan, 66506, Physics, 116 Cardwell Division Biology, 135 Ackert Kanas 66506* To whom correspondence should be addressed. E-mail: [email protected]†Deparment Chemistry.‡Department...

A new method for the in situ optical determination of soot-cluster monomer particle radius a, number monomers per cluster N, and fractal dimension D is presented. The makes use a comparison volume-equivalent sphere determined from scattering-extinction measurements RSe gyration Rg, which structure factor. combination these data with measured turbidity permits novel measurement D. parameters N are obtained graphical network-analysis scheme that compares R(se) Rg. Corrections polydispersity...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTBorohydride reductions of metal ions. A new understanding the chemistry leading to nanoscale particles metals, borides, and boratesGeorge N. Glavee, Kenneth J. Klabunde, Christopher M. Sorensen, George C. HadjapanayisCite this: Langmuir 1992, 8, 3, 771–773Publication Date (Print):March 1, 1992Publication History Published online1 May 2002Published inissue 1 March...

CuO nanorods were synthesized by hydrothermal methods with three different chemical combinations: (i) copper nitrate, lactic acid, and sodium hydroxide; (ii) sulfate, lactate, (iii) nitrate hydroxide. Physical parameters, concentration, temperature, aging time, greatly affected the size morphology of nanorods; nanoparticles also prepared. These reduced to metallic at elevated temperature 4% H2 diluted in helium. The nanomaterials (nanorods nanoparticles) was preserved after reduction. Cu...