Linear and nonlinear wave propagations of soliton-like pulse waves are studies by solving the second order ordinary differential equations numerically. The model in which the wave propagations are considered is the one-dimensional infinite lattice of an LC (inductor-capacitor) circuit with a branching point. The behaviors of the soliton-like pulse waves before and after passing through the branching point are observed in detail. These observations show that after passing through the point the original waves are split into two, reflected and transmitted, for both the linear and nonlinear cases. Although, in general, the behaviors of these two waves are very complex and difficult to analyze, a theoretical analysis using the continuous approximation to the model is possible in some cases.

抄録全体を表示

We clarify the finite temperature properties of a chiral XY-model by calculating the free energy, the entropy, the specific heat, the correlation functions and so on, by using numerical solutions of an integral equation. The specific heat has a small peak in a lower-temperature side of the main peak for the system in which the period of ground-state configuration is 1 or 4. The information stored in the ground-state configuration is disturbed easily by the temperature when the configuration is not stable. The critical behavior of the correlation length is either of the XY type or of the Ising type according to whether or not the ground-state configuration has a long period.

抄録全体を表示

The combustion process in a mixture of powdered iron and coke is simulated numerically. Complicated combustion patterns appear spontaneously due to the negative feedback effect caused by melted iron preventing the flow of oxygen. By observing the cluster size distribution of regions deprived of oxygen we find a percolation-like phase transition with the control parameter being the amount of coke.

抄録全体を表示

We have found 1⁄f  fluctuations in the mail traffic in an Internet communication, a mailng list. The flow of the mail is regular but sometimes bursts abruptly. The time sequence is intermittent. We model and simulate a mailng list on geneticalgorithm-like procedure to show 1⁄f -dependence in the limit f →0.

抄録全体を表示

Let K⁄F be finite fields with [K:F]=m. Let {u ₁,…,u_m } be a basis of this extension. By the regular representation with this basis, every element of K corresponds to an m×m matrix over F. Applying this representation, every linear code over K induces a linear code over F. Another code may be induced by another basis. We study the condition of the basis which preserves duality, and also we show the existence of such a basis for any extension.

抄録全体を表示

A criterion will be given of the existence of harmonic majorants for nonnegative plurisubharmonic functions on the generalized half-plane in Cⁿ.

抄録全体を表示

Intraluminal administration of nutrients to piglets elicited an enhancement of glicentin secretion. These results correspond with the findings obtained in experiments with dogs in terms of gut glucagon-like immunoreactivity (GLI). Although the response of pancreatic glucagon to hypoglycemia is well known, the experiment with piglets demonstrated the secretion of gut glicentin in response to hypoglycemia. Other experiments with dogs indicated that GLI secretion in response to hypoglycemia or neuroglycopenia is regulated by the parasympathetic system. However, in the postprandial state, the effect of the nervous system is weak and is overcome by the secretion of glicentin in response to the intraluminal nutrients. Ileojejunal transposition revealed intestinal adaptation, where an elevated plasma glicentin or GLI, thickening of the intestinal mucosa and an increased content of glicentin in the intestine were observed. The response of gut GLI to glucose was also exaggerated in the ileojejunal transposition dogs. These results suggest that the animal model with intestinal adaptation such as ileojejunal transposition will be useful for further research on glicentin secretion.

抄録全体を表示

The stability of human head position during walking was investigated, using angular velocity sensors, with emphasis on the effects of restriction of the visual field. The results (i) confirm the stability of head position during normal walking and (ii) demonstrate the importance of information from the peripheral visual field, as seen by differences in the amplitude of head movements. The effects of searching behavior on the head movements are discussed.

抄録全体を表示

The phenomena of centralization and decentralization in functional urban regions (FURs) in Japan are examined for a long period, covering 1947-1990. The theoretical scheme employed is an extended version of Klaassen’s spatial-cycle framework, which makes use of a growth ratio instead of the absolute level of population, and the methodological instrument is the ROXY index. The result shows that the transition in urban cycle stages for FURs of almost same size or in geographically close location have great resemblance, and that, in macroscopic view, FURs in Japan can be divided into two groups, ‘leaders’ which includes the five largest FURs and ‘followers’ which includes the other FURs. These results suggest the possibility that intra-FUR urban cycles are coupled with one another through non-linear interaction.

抄録全体を表示

This paper presents an analysis of the so-called “potential” constructions in Japanese within the framework of the Minimalist Program of Chomsky (1993). Of particular concern is how the Nominative objects in these constructions are licensed. We argue that AGRs is responsible for the licensing of the Nominative object and show that the Case realizations in potential constructions are explained straightforwardly on the assumption that the Japanese potential verb -eru has syntactic properties similar to “psych-verbs” in Italian discussed in Belletti and Rizzi (1988). We also argue that our analysis leads to a unified account of the passive constructions in Japanese.

抄録全体を表示