Ultrafast laser ablation of fused silica is studied using molecular dynamics simulations. Ionization and generation of free electrons, absorption of the laser energy by free electrons and energy coupling between free electrons and ions are considered. The BKS potential is used to describe molecular interactions and is modified to include the effect of free electrons. Temperature, density, and m...

a highly efficient, simple and green solvent-free protocol for the preparation of poly-substituted quinolines via friedländer hetero-annulation reaction between 2-aminoaryl ketones and carbonyl compounds in the presence of silica-supported p2o5 (p2o5 / sio2) is described. in this method, the title compounds are obtained in high to excellent yields and in short reaction times.

silica-bonded n-propyltriethylene-tetramine (sbnptt) was found as an efficient solid base for the synthesis of 2-amino-5-oxo-5,6,7,8-tetrahydro-4h-chromenes. chromene derivatives were obtained via the three-component condensation reaction of aromatic aldehydes, malononitrile, and dimedone at 80 oc under solvent-free conditions. the heterogeneous solid base showed much the same efficiency when u...

silica supported phosphorus pentoxide (p2o5·sio2) is an efficient catalyst for synthesis of 1,3,5-substituted pyrazoles via the condensation of 1,3-diketones and hydrazines. simplicity of procedure, mild condition, being solvent-free, high yields, and easy workup are some advantages of this protocol.

silica-bonded n-propyldiethylenetriamine sulfamic acid (spdtsa) is employed as a recyclable heterogeneous solid acid catalyst for the synthesis of benzopyrano[2,3-d]pyrimidines  through one-pot condensation reaction of salicylaldehydes, malononitrile and secondary amines  at room temperature under solvent-free conditions. spdtsa showed much the same efficiency when used in consecutive reaction ...

background: enzymes are well known as sensitive catalysts in the laboratory and industrial scale. to improve their properties and for using their significant potential in various reactions as a useful catalyst the stability of enzymes can often require improvement. enzymes immobilization on solid supports such as epoxy- functionalized ferric silica nanocomposite can be effective way to improve ...

Treatment of Chinese hamster ovary and mouse hybridoma cells with Mega-H brand silica hydride, a marketed antioxidant, after photosensitization with singlet oxygen and hydroxyl/superoxide reactive oxygen species through the use of rose bengal diacetate and malachite green resulted in an effective method of reducing free radical activity by more than 96% against singlet oxygen species and more t...

Single pulse transmissivity and reflectivity of fused silica irradiated by tightly focused 90 fs laser pulses at a center wavelength of 800 nm are numerically and experimentally investigated to study the role of nonlinear photoionization and avalanche ionization processes in free electron generation. The laser beam inside fused silica is modeled with a 2+1 -dimensional propagation equation whic...