Light attenuation in a semitransparent foam sheet-Thickness measurement for industrial use

An optical method for measuring the thickness of heterogeneous materials has been studied. The method is based on the light attenuation theory. A complete system has been constructed in order to demonstrate the applicability of the present method for industrial use. The experimental set-up consists of semiconductor lasers, focusing lenses, photo-diodes serving as a power meter and a personal computer with an A/D converter for data acquisition. Averaging of numerous measurements is required in the present method because the heterogeneous cell structure of the foam material yields large fluctuations in transmitted light levels. The fluctuations can be reduced to below 1% of the transmitted light power by 80 times averaging. The error of the measurement is considered to be a few tens of micrometers in thickness. The present system is capable of sampling data at a rate of 400 Hz and has been successfully applied to a manufacturing process.     

Integrated Image Associative Memory and Its Optical Implementation

We present the concept of integrated processing to combine intuitive processing of neural networks with logical processing of the conventional digital computer. We investigate a way to embody the concept in the neural network system by introducing external constraints in terms of external input. The effect of the external input is analyzed using the generalized projection method. The concept of integrated processing is applied to an image associative memory system, and the system is optically implemented for high-speed parallel processing incorporating it with the computer. The experimental result is presented to illustrate the effectiveness of the external input to control the output of the image associative memory.     

Base-induced rearrangement of 1-trimethylsilylpropargyl alcohol. Generation of lithiated trimethylsiloxyallenes and their reactions

Under the effect of butyllithium, 1-trimethylsilylpropargyl alcohol undergoes rearrangement to afford the corresponding trimethylsiloxyallene or its lithiated one, which can be used for the preparation of α,β-unsaturated ketone derivatives.     

Temperature dependence of the dynamic interstitial interactions in potassium bromide

Formation of the H and H_A centers in Na⁺-doped KBr within the time constant of the thermal annihilation of the H center is measured between 80 and 200K and it is shown that the volume of the interaction of the radiation-induced replacement sequence of an interstitial halogen with a Na⁺ impurity increases with an activation energy of (0.025 ± 0.005) eV as the temperature rises.     

Spectra and emission lifetimes of H2CS(Ã 1A2)

Fluorescence spectra and lifetimes of single vibronic levels of the first excited singlet state of H₂CS have been measured under effusive flow conditions. Fluorescence lifetimes of the single vibronic levels decrease from 140±3 μs (0°) to 68 μs(3¹4¹5¹) with increasing excitation energies. The promoting vibrational modes for the non-radiative transition are considered to be the out-of-plane bending (ν₄) and the asymmetric rocking (ν₆) modes rather than the asymmetric stretching mode (ν₅).     

New condensing reagents for stereospecific synthesis of dinucleoside monophosphate aryl esters

Condensation of 5′-O-dimethoxytritylnucleoside 3′-O-(o-chlorophenyl) phosphates and 3′-O-benzoylnucleosides with a new condensing reagent, 2,4,6-triisopropylbenzenesulfonyl 5-(pyridin-2-yl) tetrazolide gave o-chlorophenyl ester of protected dinucleoside monophosphates which had a stereospecific configuration. The corresponding mesitylenesulfonyl derivative gave similar results.     

Development of high-radiation-sensitive polymer gel for magnetic resonance imaging in three-dimensional dosimetry

We developed a high radiation sensitive polymer gel by modifying the amounts of the gel components and the temperature for the gel preparation. We evaluated its relaxation time linearity against dose and compared the measured dose distribution with the calculated one. For the relaxation time-dose linearity, irradiations were carried out with a linear accelerator using 6 MV photons and doses ranging from 0-5.0 Gy. The relationship between dose and R(2) value (reciprocal of T(2) relaxation time) was measured and it had good linearity over a wide range (0.3-5 Gy). The measured dose distributions were in good agreement with calculated ones. Since the present gel has higher sensitivity and it is synthesized more easily at lower cost than conventional polymer gels, we expect to see improved three-dimensional (3D) dosimetry using it.