polyvinylidene fluoride/polyvinylpyrrolidone (pvdf/pvp) hollow fiber membranes were fabricated by dry-jet wet-spinning process. the correlated effects of the air gap length and pvp concentration ((1) the air gap length effect at the low and high pvp concentration in the dope solutions, as well as (2) the effect of the pvp concentration at the same air gap length) on the cross-section structure ...

this paper investigates hollow and porous alumina nanospheres that were previously synthesized to be used for the dehydration of methanol to dimethyl ether (dme). as hollow nanostructures possess characteristics such as low density and high surface to volume ratio, their catalytic activity between hollow and porous structure is compared. for this purpose, three most important parameters (acidit...

We are developing a new method using ultrasonic longitudinal and torsional vibration of a hollow-type stepped horn for hole machining. We foresee that the equipment can be simplified and miniaturized. In this paper, ultrasonic vibration sources of a hollow-type stepped horn without a diagonal slits vibration converter and with a diagonal slits vibration converter are used. The longitudinal and ...

We developed a process to fabricate 150-700 nm monodisperse polymer particles with 100-500 nm hollow cores. These hollow particles were fabricated via dispersion polymerization to synthesize a polymer shell around monodisperse SiO(2) particles. The SiO(2) cores were then removed by HF etching to produce monodisperse hollow polymeric particle shells. The hollow core size and the polymer shell th...

Gold nanoparticles are emerging as promising biomedical tools due to their unique nanoscale characteristics. Our purpose was to synthesize a hollow-shaped gold nanoparticle and to investigate its effect on human aortic endothelial cells (HAECs) in vitro. Hollow gold nanoshells with average 35-nm diameters and 10-nm shell thickness were obtained by galvanic replacement using quasi-spherical nano...

The preparation of luminescent silver hollow spheres using Eu(III) compound based on trifluorothenoylacetone is described. The structure and size of silver hollow spheres were determined by TEM images. The result shows the formation of hollow structure and average size of the silver hollow spheres (0.9 lm). The silver hollow spheres were further characterized by UV absorption spectrum, SNOM and...

Plasma generation over large areas using a hollow cathode discharge is described in this study. Radio frequency linear hollow cathodes in several arrangements, for operation at reduced gas pressure and suitable for scale-up, are presented. Examples of surface processing and coating by PVD, both by hollow cathode discharge (HCD) and hollow cathode arc (HCA), are given. A non-equilibrium atmosphe...

Monodisperse spherical hollow and non hollow titania particles of variable sizes are produced in a sol gel synthesis from Ti(EtO)4 in ethanol. Hollow spherical particles of rutile were obtained by coating colloidal polystyrene beads with a titanium oxide hydrate layer and subsequently calcination at elevated temperatures in ol\ygen atmosphere. The non hollow titania particles were produced in t...

Bullet rosette particles are common in ice clouds, and the bullets may often be hollow. Here the singlescattering properties of randomly oriented hollow bullet rosette ice particles are investigated. A bullet, which is an individual branch of a rosette, is defined as a hexagonal column attached to a hexagonal pyramidal tip. For this study, a hollow structure is included at the end of the column...

Magnetic hollow spheres with a controlled diameter and shell thickness have emerged as an important class of magnetic nanomaterials. The confined hollow geometry and pronouncedly curved surfaces induce unique physical properties different from those of flat thin films and solid counterparts. In this paper, we focus on recent progress on submicron-size spherical hollow magnets (e.g., cobaltand i...