Transparent free-standing mesoporous silica (MS) films were synthesized from a system of TMOS-Brij-Acid-H2O. The non-ionic surfactants used included Brij 22 (C12EO10OH), Brij 56 (C16EO10OH), and Brij 76 (C18EO10OH). The acids used include HCl, H3PO4, and CF3SO3H. The effect of synthesis parameters on the synthesis and the proton conductivity of mesoporous silica were investigated. The Brij 56/C...

Iron oxide occurs as a dust in many industries apart from iron-ore mining. It is found in silver polishing, electric welding, and boiler scaling, as well as in the more obvious metal grinding, fettling, and blast furnace working where it may be mixed with varying amounts of silica. Some still consider iron oxide a harmless dust (Baldi, 1952) while others think that, like coal, it can produce ch...

In our continuous investigation for free radical scavengers from extracts of fruit body of basidiomycetes, we have isolated four new p-terphenyl compounds, designated as curtisians A-D, from the methanolic extract of the fruit body of Paxillus curtisii. These compounds were isolated by silica gel and Sephadex LH-20 column chromatographies, preparative-TLC and HPLC, consecutively. The structures...

3,4-dihydropyrimidin-2(1h)-thiones were synthesized in the presence of ag nanoparticle/melamine sulfonic acid (msa) supported on silica gel. the reaction was carried out at 110 oc for 20 min under solvent free conditions. in all cases, the three component reaction proceeded smoothly to give the corresponding 3,4-dihydropyrimidin-2(1h)-thiones in moderate to good yield. we have found the best co...

A facile spray drying technique has been developed for large-scale and template-free production of nanoporous silica with controlled morphology, large pore size, and high pore volume, using commercially available fumed silica, Aerosil 200, as a sole precursor. This approach can be applied to the preparation of functional nanoporous materials, in this study, lanthanum oxide functionalised silica...

We demonstrate and discuss acoustic vibrations in spherical shell particles. The particles consist of 38-nm-thick gold shells, sandwiched between an inner silica core of 456 nm in diameter and an outer silica shell of 10 nm in thickness. Employing standard and asynchronous optical sampling (ASOPS) ultrafast pump-probe experiments, we excite acoustic vibrations of the shells and detect the oscil...

The presented work focuses on the synthesis of silica-based macroporous aggregates composed silica nanoparticles using a template-free method. To improve mechanical strength prepared fractal-like aggregates, precursor tetraethyl orthosilicate (TEOS) is used during nanoparticle aggregation. obtained results confirm possibility to tailor pore size distribution (PSD) simply by primary particles va...

author reports a case of 67- years- old men referred to donga university hospital silicosis who had worked in tunnel drilling where presumably had been exposed to high concentration free silica for almost 20 yr. this report is considered the first in korea to the best of our knowledge since no cases on silicosis could be reported in this occupation in reviewing various literature sources in kor...