The density tapered planar array antennas can be designed by element thinning. The method of element thinning employed here is the deterministic method that has been proposed for linear array antennas, and the modification of deterministic method for planar array antennas is described. Although the result by this method is comparable with one by the statistical method that has been used in many applications, this method is not iterative one and the result is unique. The sidelobe level, for example, is -25.51dB where the array contains 1818 elements arranged with a circular aperture capable of 3259 elements if fully filled.

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The behavior of bedrock faults are reproduced by the model test and the numerical simulation. The model test have to solve the problem of scale effect reduced from prototype to model. In this paper, shows the experimental device thought scale effect on stack of aluminum rods by vertical fault, discusses the relation between stress and deformation of ground formed shear bands.

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[in Japanese]

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Derivation of stable equilibrium paths of a elastic rectangular plate may require the huge amount of calculation to evade the singular points on it. Moreover, the combination of structual instability and plasticity of materials offers the complicated problems in the procedure of numerical calculations. For example, when a rectangular plate subject to the uniform enforced displacement, the plastic buckling occurs, and after that, the deformation modes are localized. The dynamic relaxation method (DRM) is expected to give the stable equilibrium solution as a stationary value of the dynamic ploblems of damped free vibration. Thus, this DRM will give us the realistic and unique solution of equilibrium state by overcoming the singular points and material nonlinearity. In this paper, the plastic buckling and post-buckling analyses eliminating the numerical "Strain Reversal Phenomena" are carried out to investigate the applicability of DRM.

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[in Japanese]

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It is very important for the students at National College of Technology to be able to explain various things concerning to their specialities in English, because they will surely have needs to communicate with technical experts from various countries in this internationalizing age. For this matter, we should give them some practice in our class as a preparation for their future needs. It is one such way to make them explain in simple English general things around them. While they learn how to give explanation or definition on such things by themselves, they can get the basis for acquiring vocabulary and expressions needed to improve their communicative competence with foreign technical experts in the future.

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It is important to decide what items in grammar should be taught at first when we teach a language especially to beginners. This research deals with the critical issue by using the data that are got by checking the students' usage of grammatical morphemes in essay writing from both correct usage and usage of errors. The examinees are the three grades of Kisarazu National College of Technology (KNCT is used as abbreviation form in this thesis), and 1st year students of Keiai Junior College students for two years. At the end of the thesis the author of this thesis proposes some issues to promote the researches in the field of Second Language Acquisition, especially in the Sequence of Acquisition items.

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[in Japanese]

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