Racemic and highly enantioenriched 3-methoxycarbonyl, 3-carboxy, and 3-hydroxymethyl derivatives of dibenzo[6]helicene were prepared. The Langmuir layers of these helicenes were formed at the air–water interface and transferred onto solid substrates to afford Langmuir–Blodgett films, which were then studied by ambient atomic force microscopy and (chir)optical spectroscopy. Significant differences were found in the behaviour of the Langmuir layers as well as in the morphology, UV/Vis, electronic circular dichroism (ECD), and fluorescence spectra of the Langmuir–Blodgett thin films depending on the molecular chirality and nature of the polar group. The experimental results were supported by molecular dynamics simulations. 相似文献
An enhanced material-classification algorithm using turbulence-degraded polarimetric imagery is presented. The proposed technique improves upon an existing dielectric/metal material-classification algorithm by providing a more detailed object classification. This is accomplished by redesigning the degree-of-linear-polarization priors in the blind-deconvolution algorithm to include two subclasses of metals--an aluminum group classification (includes aluminum, copper, gold, and silver) and an iron group classification (includes iron, titanium, nickel, and chromium). This new classification provides functional information about the object that is not provided by existing dielectric/metal material classifiers. A discussion of the design of these new degree-of-linear-polarization priors is provided. Experimental results of two painted metal samples are also provided to verify the algorithm's accuracy. 相似文献
To Bi or not to Bi? The synthesis of phosphorus nanorods of two differing morphologies is reported, in both the presence and absence of a bismuth catalyst. Not only do these materials represent a new class of elemental nanorods but they also give valuable insight into the complex allotropy of phosphorus.
The amphiphobic nature of carbon nanotubes allows them to stabilise droplets of water-insoluble monomers dispersed in the aqueous nanotube suspension, leading to a flexible route to electrochemical synthesis of useful nanoporous composites of nanotube doped conducting polymers, and potentially to other chemistry involving reactants incompatible in the same medium. 相似文献
Order - We show that the poset of copies $\mathbb {P} (\mathbb {Q}_{n} )=\langle \{ f[X]: f\in \text {Emb} (\mathbb {Q}_{n} ) \},\subset \rangle $ of the countable homogeneous universal n-labeled... 相似文献
Surface air concentrations of plutonium isotopes at the Vinca-Belgrade site for the period May 1–15, 1986, are reported. The increase in238Pu/239,240Pu ratios confirms that the source of plutonium in surface air was the Chernobyl accident. 相似文献
Laser ablation of Mn target in vacuum and in the presence of CH4 was
studied under 308 nm laser irradiation. Time-resolved emission using gated
detection and scanning monochromator and absorption using the cavity ring-down
spectroscopy were used to study vaporized plume. In the CH4 atmosphere we
observed transitions identified as C2 and MnH bands, while these spectral
features were not detected in emission spectra. This is a clear evidence of
importance in combining both spectroscopic techniques in laser vaporized plume study. 相似文献