New photographs of the far ultra-violet spectrum of benzene are presented. The absorption from 2000 to 1800A (Amlx, c. 1980A) is regarded not as a part of the much stronger absorp­ tion of peak at 1790 A but as due to a separate transition. Sharp bands lying at 1790 A represent the first member of a previously reported Rydberg series. The spectra of toluene, xylene, monochloroando-dichlorobenze...

Here we describe the metathesis reactions of a strained eight-membered ring that contains both alkene and alkyne functionality. We find that the alkyne metathesis catalyst produces polymer through a ring-opening alkyne metathesis reaction that is driven by the strain release from the monomer. The strained monomer provides unusual reactivity with ruthenium-based alkene metathesis catalysts. We i...

The effect of the excitation wavelength on the charge recombination (CR) dynamics of several donor-acceptor complexes (DACs) composed of benzene derivatives as donors and of tetracyanoethylene or pyromellitic dianhydride as acceptors has been investigated in polar solvents using ultrafast time-resolved spectroscopy. Three different wavelength effects have been observed. (1) With complexes exhib...

A detailed investigation has been made into the antiaromaticity and chemical reactivity of a planar cyclooctatetraene (COT) molecule fully annelated with bicyclo[2.1.1]hexane units 2. In spite of its planar 8pi-electronic structure, theoretical calculations have indicated that the antiaromaticity of COT 2 is considerably decreased in comparison with a planar COT 16 with D 4h symmetry. This beha...

In this paper, we describe a new region-based approach to active contours for segmenting images composed of two or three types of regions characterizable by a given statistic. The essential idea is to derive curve evolutions which separate two or more values of a predetermined set of statistics computed over geometrically determined subsets of the image. Both global and local image information ...

Separation of highly similar molecules and understanding the underlying mechanism are of paramount theoretical and practical importance, but visualization of the host-guest structure, energy, or dynamism is very difficult and many details have been overlooked. Here, we report a new porous coordination polymer featuring hierarchical porosity and delicate flexibility, in which the three structura...

This article is concerned with the design and implementation of a system for real-time monocular tracking of a moving object using the two degrees of freedom of a camera platform. Figure-ground segregation is based on motion without making any a priori assumptions about the object form. Using only the first spatiotemporal image derivatives, subtraction of the normal optical flow induced by came...

The conditions of the reaction of malononitrile dimer with enaminones and arylidenemalononitrile could be adapted to yield either pyridines or benzene derivatives. A new synthesis of pyrido[1,2-a]pyrimidines from the reaction of malononitrile dimer 1 and 2-phenyl-3-piperidin-1-yl-acrylonitrile (11) is described. Compound 1 condensed with DMFDMA to yield an enaminonitrile that reacted with hydra...

An assay technique, homogeneous enzyme immunoassay, is described for the quantitative determination of morphine derivatives in biological fluids. An enzyme is labeled with morphine. When the enzymelabeled morphine is bound by antimorphine antibodies, the enzyme is rendered inactive. Free morphine competes with enzyme-morphine for antibody binding sites preventing inhibition of enzyme activity. ...