The thermal fluctuation of mirror surfaces is the fundamental limitation for interferometric gravitational wave (GW) detectors. Here, we experimentally demonstrate for the first time a reduction in a mirror's thermal fluctuation in a GW detector with sapphire mirrors from the Cryogenic Laser Interferometer Observatory at 17 and 18 K. The detector sensitivity, which was limited by the mirror's thermal fluctuation at room temperature, was improved in the frequency range of 90 to 240 Hz by cooling the mirrors. The improved sensitivity reached a maximum of 2.2×10(-19) m/√Hz at 165 Hz.
High-resolution NMR spectra of chlorinated polyethylenes with various chlorine contents were measured on a-dichlorobenzene solutions at ca. 160°C. The chemical shifts for the resonances associated with the distribution of chlorine atoms along the polymer chain were resolved by the triad or pentad units, and content of the chemical units was quantitatively obtained. Chemical units containing geminal dichloride were observed when chlorine content approached ca. 40 wt %. The structure of chlorinated polyethylenes in the region of chlorine content below 40 wt% is characteristic of the statistically random distribution of chlorine atoms along the polymer chain. Various methylenes and methynes in various proton environments were observed, but chemical units such as vinylidene chloride sequences were not observed in the chain. It was found that a chlorination condition slightly affected the chlorine distribution, namely the solution chlorination increased vicinal-dichloride units rather than geminaldichloride units. However, the molecular weight of the parent polymer did not affect the chlorine distribution of chlorinated polyethylenes. The sequence-length distribution of methylenes was also obtained and the contents of longer methylene sequences (-(CH2)n-, were computed using the results of Frensdorff and Ekiner's theoretical treatment. KEY WORDS Chlorinated Polyethylenes I High-Resolution NMR I Assignment I Chlorine Distribution I Methylene-Sequence Length I a, w-Dichloroparaffins I Vinyl Chloride-Ethylene Copolymer I Hydrogenated Poly(Vinyl Chloride) I
The aim of the present study was to assess the potential of biocompatible polymeric nanosheets as topical and transdermal drug-delivery devices. Nanosheets are two-dimensional nanostructures with a thickness in the nanometer order, and their extremely large aspect ratios result in unique properties, including high transparency, flexibility, and adhesiveness. Nanosheet formulations containing betamethasone valerate (BV) as a model drug and consisting of poly (L-lactic acid) or poly (lactic-co-glycolic) acid were fabricated through a spin-coating-assisted layer-by-layer method using a water-soluble sacrificial membrane. The fabricated formulations could incorporate and release higher amounts of BV compared with a commercial ointment, and the amounts could be controlled by the polymers used, the amount of BV added, and the use of controlled-release membranes. The presence of BV had a minimal effect on thickness, transparency, adhesiveness, and moisture permeability of nanosheets, permitting their application to any area of skin for a long period of time. Therefore, this biocompatible polymeric nanosheet formulation represents a novel and promising topical and transdermal drug delivery device, which has potential to deliver drugs regardless of the area of skin.
Pervaporation enrichment of chlorine containing organic hydrocarbons from dilute aqueous flux 24 g/m2. hr were obtained at 25•Ž, about 0.2 wt.% aqueous feed composition for copoly (BA-acrylic acid) membrane.
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