Among several star molecules studied so far, the results for two similar but slightly different systems composed of all hydrophobic components, i.e. one low Tg arm and two high Tg arms were compared and discussed mainly. They are polyisoprene‐arm‐polystyrene‐arm‐poly(2‐vinylpyridine) stars and polystyrene‐arm‐polybutadiene‐arm‐poly(2‐vinylpyridine) ones, and are abbreviated as ISP and SBV, respectively, in the original literatures. Several periodic Archimedean tiling patterns can be naturally formed when the relative lengths of three chains are similar one another in both series. Core‐shell type morphologies and actually three‐phase four layer lamellar structures were also commonly observed for two series. A quasicrystalline tiling with dodecagonal symmetry can also be conformed at the targeted composition of ISP/homopolymer blend and a zinc‐blende type structure was created at just a little outside of tiling region for the same blend. Furthermore, the several interesting structures from amphiphilic molecules, composed of a hydrophilic component, poly(ethylene oxide), a hydrophobic component, polymethylmethacrylate and a highly water‐repellent polymer poly(perfluoropropyleneoxide) are described and introduced.
Syn-gled out: The syn diastereo- and enantioselective addition of azlactones to 3-vinylindoles was accomplished by using a chiral, binapthol-derived, Br?nsted acid catalyst (see scheme). This method enables facile access to tryptophan derivatives with adjacent quaternary and tertiary stereogenic centers, which are potentially useful for the synthesis of peptidomimetics. 相似文献
Crystal growth of GaAs layers and InAs quantum dots (QDs) on the GaAs layers was investigated on Ge/Si substrates using ultrahigh vacuum chemical vapor deposition. Ga-rich GaAs with anti-site Ga atoms grown at a low V/III ratio was found to suppress the diffusion of Ge into GaAs. S-K mode QD formation was observed on GaAs layers grown on Ge/Si substrates with Ga-rich GaAs initial layers, and improved photoluminescence from 1.3 μm-emitting InAs QDs was demonstrated. 相似文献
We report a simple, sensitive, and rapid detection of captopril using copper(II) and a bare glassy carbon electrode with cyclic voltammetry. The captopril is detected by the formation of a copper(II)‐captopril complex that is observed to have a characteristic oxidation potential at+0.24 V vs. Ag/AgCl. It is found that the peak current varies linearly with the concentration of captopril. The linear dynamic range is obtained for a captopril concentration of 1 µM to 10 µM, and the sensitivity is found to be 0.10±0.003 μA μM?1. Importantly, the low limit of detection (n=3) of 0.10 μM and the precision of 3.2 %, are achieved using a simple, unmodified electrode. This is attributable to in situ adsorption of a copper(II)‐captopril complex on the electrode surface. 相似文献
We give criteria for finite and countable powers of a space similar to the Michael line being Lindelöf. As applications, we give examples related to Lindelöf property in products of spaces of Michael line type and in products of spaces of continuous functions on separable -compact spaces.
Major and trace elements (Na, Mg, Al, Si, P, K, Ca, Ti, Mn, Fe, Rb, Sr, Y, Zr, La, Ce, Pr, Nd, Sm, Gd, Dy, Th and U) in igneous rocks were assayed with fused lithium borate glass beads using X-ray fluorescence spectrometry. Low dilution glass beads, which had a 1:1 sample-to-flux ratio, were prepared for determination of rare earth elements. Complete vitrification of 1:1 mixture required heating twice at 1200 degrees C with agitation. Extra pure reagents containing determinants were used for calibrating standards instead of the rock standard. The calibration curves of the 23 elements showed good linearity. Furthermore, the lower limits of detection corresponding to three times the standard deviation for blank measurements were 26 mass ppm for Na2O, 6.7 for MgO, 4.5 for Al2O3, 4.5 for SiO2, 18 for P2O5, 1.1 for K2O, 4.0 for CaO, 3.9 for TiO2, 1.6 for MnO, 0.8 for Fe2O3, 0.5 for Rb, 0.2 for Sr, 0.4 for Y, 0.5 for Zr, 3.3 for La, 6.5 for Ce, 2.7 for Pr, 2.1 for Nd, 1.7 for Sm, 0.7 for Gd, 2.7 for Dy, 0.5 for Th, and 0.6 for U. Using the present method, we determined the contents of these 23 elements in four rhyolitic and granitic rocks from Japan. 相似文献
