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Thermal convection and thermophoresis induced by mum-scale local heating are shown to elongate a single DNA molecule. An infrared laser used as a point heat source is converged into a dispersion solution of DNA molecules, which is observed under a fluorescent microscope. The thermal convection around the laser focus manifests as extensional flow for the long DNA chain. A simulation of thermal convection that reproduces the experimental condition provides numerical support for the stretching caused by thermal convection. This DNA elongation technique is a novel method for manipulating the intact single DNA molecules, and it can be applied to a "lab on a chip".

A method to evaluate the octane number of automobile gasoline by proton magnetic resonance (PMR) has been developed. Twenty-one samples, ranging in octane number from 80 to 100, were produced by preparing different blends of gasoline bases, and the dispersion of each sample in a pattern space was examined by applying the display methods, among various pattern recognition methods, to its PMR spectrum. This report concerns the result of the study, which revealed that the octane number of a given type of automobile gasoline could be visually estimated from its PMR spectrum.

A method to assess the octane number of motor gasoline by proton magnetic resonance (PMR) spectrometry was studied. Twenty-eight kinds of regular gasoline and 24 of premium gasoline were sampled from the market from winter to summer, and their PMR spectra were classified by a supervised learning pattern recognition method, an unsupervised learning pattern recognition method, and other related methods. This report concerns a successful attempt to identify regular and premium gasoline by PMR spectrometry.