This paper shows an improved rate equation by which the phase relation of the carriers and inhomogeneous property are taken into account for injection lasers. The direct modulation characteristics were analyzed as an application of this improved rate equation. A more general discussion was obtained for the resonance-like phenomenon and its suppression effect. For the undoped AlGaAs DH laser with index guiding structure, it is found that the resonance-like phenomenon is mainly suppressed by effect of spatial diffusion of injected carriers, reduction of the thresh-old level and lateral singlemode-operation. We also found that other mechanisms, such as mixing effect of the spontaneous emission, variation of longitudinal mode number and the intra-band relaxation, hardly affect to suppress the resonance-like phenomenon.

The features of n-channel polysilicon-gate MOS integrated circuits with ion-implanted polysilicon resistor load are described. A ring-oscillator circuit and a divider circuit are used for the performance evaluations. Switching delay time of 1.0 ns and power-delay product as small as 0.1 pJ are obtained at 2V supply voltage for the ring-oscillator. In a divider circuit, input frequency up to 80 MHz can be divided at 2V. The electrical characteristics can be varied by changing sheet resistance of the load resistors, while the power-delay product are nearly constant. Based on the experimental results, electrical characteristics of resistor load MOS circuits using the scaled-down MOS FET's are discussed.

A method to obtain optimal channel graphs (least blocking probability) is described, for a class of 4-stage link systems without parallel" limitation. Slip notation, introduced to classify and identify channel graphs effectively, makes their comparison tractable. General blocking probability calculation procedure is obtained for this purpose. Generalized optimums are concretely determined for a range of small link sizes, and assured by the comparison with every non-slip type. Former parallel" optimums are proved to be inferior, but practically sufficient according to numerical results. Necessary conditions for generalized optimums are shown based on a theorem.

This letter presents definitions of connectivity among volume cells of a three-dimensional (3-D) digitized binary picture, and an explicit formula to calculate the Euler number of a 3-D object in a given 3-D picture.

Traveling-wave light intensity modulator was constructed using the 5 µm wide strip optical waveguide of z-cut LiNbO₃ and the asymmetric stripline as the modulator electrode. The half-wave voltage of 23 V and the extinction ratio of 97% were achieved. Modulation was performed up to 18 GHz.

System for the measurement of the respiratory response of human is introduced. This system has the facilities to supply the air which is mixed with CO₂ or N₂O. The subject inhales the gas of which contents variation can be controlled by the program. The system also measures the respiratory response of the subject which is caused by the changes of atmospheric circumstances, i.e., CO₂ inhalation and records data. To check the concentration of agent gas according to the program, micro computer is used. Flow volume of expired gas, heart rate, concentration of supplied gas and that of expired gas are collected. One of the experiments in case of CO₂ inhalation is shown. In this experiment the subject inhales the air which is mixed with CO₂. Its pertition is 5% of the total volume.