Key techniques to control porous microsphere morphology in S/O/W emulsion system

A solid-in-oil-in-water (S/O/W) emulsion system has been developed to prepare porous polymeric microspheres. The obtained microspheres showed unique core–shell structure with a dense core and a surface porous layer. The emulsion system has two processes. In the first process, S/O/W₁ viscous emulsion is prepared by dropping of S/O phase in the first water phase (W₁). In the second process, the S/O/W₁ emulsion is poured to another water phase (W₂) as S/O/W₁/W₂ emulsion. During the process, S/O/W₁ droplet becomes microsphere after organic medium completely diffusion. Emulsion techniques have various effective combinations such as additive and process conditions to design microsphere morphology. With regards to the proposed S/O/W system, addition of the solid phase in the system is a key factor to form the porous structure. When the medium diffusion starts, the solid makes W₁ phase kept inside the S/O/W₁ droplet. The remained W₁ phase changes surface porous layer after purification. Affinity between the solid and oil phase should be adjusted as well. In this study, an optimization of the emulsion system was attempted considering solubility parameter and polarity. Additionally, it is found that process conditions could help to design microsphere morphology such as pore size and porous layer thickness.     

Highly reproducible technique for three-dimensional nanostructure fabrication via anodization scanning probe lithography

The effects of coated materials for Si probes on the sizes of line structure by using anodization scanning probe lithography (SPL) are investigated by using atomic force microscopy (AFM). Anodization SPL was carried out on the 1-decane monolayer directly attached to hydrogen-terminated silicon. Gold-coated, diamond-coated, and uncoated Si probes were used as the SPL probes in order to fabricate line structures of silicon oxide. In the cases of Au-coated and uncoated Si probes, the widths of line structures are widely influenced by the changes of scanning rate and applied bias voltage. However, the line width fabricated by use of the diamond-coated probe maintained 15 nm under any condition of scanning rate and applied bias voltage. One of the most narrow and three-dimensional nanostructures is found to be successfully fabricated on the hydrogen-terminated Si substrates when the diamond-coated probe was used as a probe of anodization SPL. In addition, this result indicated that high reproducibility of oxide nanostructures is attainable by anodization SPL used the diamond-coated probe.     

Heavy ion physics with the ATLAS detector

The European Physical Journal C - Recent results from RHIC experiments suggest that a hot and dense QCD matter, which maybe the quark gluon plasma (QGP), is formed in Gold+Gold collisions at a...     

High-performance liquid chromatographic analysis of ginsenosides inPanax ginseng extracts using glass-ODS column

Summary Octadecyl-porous glass was prepared and used as the packing for reversed-phase high-performance liquid chromatography. A mixture of ginsenosides, saponins of ginseng was analyzed with detection at 203 nm. Ginsenosides Rf, Rg₂, Rb₁, Rc, Rb₂, and Rd were separated with acetonitrile-water (27.5:72.5) as the mobile phase. A well-resoluted chromatogram of ginsenosides Ro, Rg₁ and Re was also obtained with acetonitrile-water (16.5:83.5). The whole separation was achieved in 12 min with a flowrate of 1 ml/min. Calibration curves of ginsenosides Rb₁, Rc, Rb₂, Rd, Rg₁ and Re were linear up to 5 μg. It can be concluded that the rapid and accurate analysis of ginsenosides is possible by the described method.