When paramecia are exposed to a.c. electric field of appropriate strength, the cells show following characteristic behavior in hay infusion with increasing the frequency; (1) the cells repeat going and returning parallel to the lines of the electric field until the frequency reaches about 1 Hz. (2) the cells perform circular movement with their peristome to direct toward the outside of the circle between 1 Hz to 5 Hz and then (3) do rotational movement between about 5 Hz to 500 Hz. As the frequency of the supplied electric field is increased, (4) the cells become swimming perpendicular to the lines of electric field. Beyond the frequency of 2 kHz, (5) the cells swim freely as if the electric field was not supplied. Cell motility of paramecia under d.c. electric field is also examined. On the base of the results obtained, excitability of the cells exposed to the electric field is discussed.

A Sheffer function is a Boolean function such that one can produce all Boolean functions by using it as a sole basic logic element, and a typical example is the NAND operation. Here we investigate two variations of this concept, that is, Sheffer with constants" and Sheffer with constants under uniform composition". These are considered as more suitable assumptions complying with real electronic circuitry. Our new results in this paper are two explicit formulas, one for the number of n-variable functions Sheffer with constants, and the other for that of those uniformly Sheffer with constants. In particular, it is shown that almost all functions are Sheffer with constants when n is large. Some numerical values of these numbers are calculated in the range of 1n6.

Low-loss and long-length single-mode fibres have been fabricated by the VAD (Vapour phase axial deposition) method. The most important technique was a new torch development in order to form a thick low-loss cladding region in the thin porous preform. The best loss values for the VAD single-mode fibres were 0.35 dB/km at 1.3 µm and 0.2 dB/km at 1.55 µm. The OH absorption loss at 1.39 µm in the fibre was reduced to less than 0.1 dB/km. Moreover it turned out that VAD fibres had less tendency of the loss increase with increasing Δn than MCVD fibres.

Some properties of periodically correlated stochastic processes such as the mean ergodicity and asymptotic befavior of the periodgram of the processes are studied in this paper. A periodically correlated process (PC-process) is also called periodic nonstationary process, cyclo stationary process and even periodic stationary process although the process may not be stationary, and these are mainly studied as models of signals especially as pulse trains in the communication theory. Although many of interesting results obtained so far are important from the theoretical point of view, they are rather intuitively derived. Therefore we reformulate the process in a rigorous manner, introduce the spectral representation of it when the process is harmonizable in Loève's sense and study mainly about the mean ergodic properties and the limiting behavior of the mean periodgram of the process. Furthermore we study some pulse train processes as particular examples and we show simple examples of nonharmonizable PC-processes which had been thought of as unusual. We point out that by such a theoretical treatment, the position of PC-processes in the theory of nonstatonary processes will be better recognizable and the results obtained here will be useful as the foundation of practical time series and signal analysis in the communication and information theories.

In this paper we have represented a model structure of modal lower (first-order) predicate logic (S5) (abbr. MLPC in our paper) in two-sorted extensional language (abbr. EL₂), and tried to translate a formula of MLPC into a formula of two-sorted logic (abbr. ELPC) in such a way as preserving provability. (i.e.P in MLPC iff P^* in ELPC, where P^* is the translation of P). Roughly speaking, modal symbol (necessity) is translated into the universal quantifier k of the domain which expresses the set of possible worlds, and n-ary predicates are n1 -ary predicates. For instance, xP (x) is translated into kx^*P^* (x^*, k), where ^* denotes the translation. Therefore it is possible to replace a theorem proving of MLPC with that of two-sorted logic ELPC, so we have shown it possible to prove a theorem of MLPC by using the resolution principle in ELPC. Then the completeness of the resolution in two-sorted logic is proved, and a normal form of MLPC is introduced. It is shown that for any formula of MLPC there exists an algorithm to transform the formula into its normal form. This normal form is obtained by decreasing the number of modal symbol in a formula as possible. For instance, xP (x) yQ (y) is transformed into xy (P (x) Q (y)).

A recognition method of printed Thai characters by the structural analysis of their contours is described. Digital contours of characters are encoded according to directional differences of contour tracing, then, simple arithmetic operations are applied to eliminating noises and extracting concavities and convexities of the contours. Several geometric features of concave and convex arcs are used to calculate similarities of the arcs, then, a pair of the most similar arcs between a model and an input character is determined from the similarities. Finally, for recognizing characters, the similarity between each arc pair of the character portion and the similarity between characters are calculated. By applying the method to 67 categories (670 data) of Thai characters, a very high recognition rate has been obtained.

The deconvolution of DLTS signals for multiple deep traps has been automated to reduce the data processing time of DLTS signals analysis and to improve the accuracy of the measurement. A linear non-recursive optimum filter is used for the deconvolution and peak-chaining algorithm has been developed to automate the Arrhenius plotting procedure. The design of the filter, the peak-chaining algorithm and an example of the deconvoluted DLTS signal are described as well as a performance evaluation of the method.

Diversity reception of binary NCFSK through Nakagami fading channels and additive white Gaussian noise using ideal switched diversity is considered. Identical as well as different branch parameters are assumed. The effect of correlation among the branch fadings is also considered.

The designs and experiments for the carousel SQUID logic gate are pursued. The novel rf-magnetoron cathode is employed for the formation of tunnel barriers to obtain stable Josephson junctions for heat-cycles with small leak current. The sharp changes of a gate current by the applied control current are observed in the fabricated carousel SQUID gate.

We present an Isometric Context-Free Array Grammar (ICFAG) that generates the set of all solid upright rectangles. This is performed by using the property that blank symbols in the rewriting rules enable ICFAGs to sense the local shapes of the host array. Thus ICFAGs are context-sensitive in some sense.

In this paper presented is a theorem: a planar digraph which is embedded in a plane and which has a single source and a single sink both lying on the outer face of the digraph, is acyclic, if and only if all the inner faces are acyclic. Hence the number of tiesets necessary and sufficient for guaranteeing the acyclicity of the digraph is equal to the nullity of the digraph.