The trend toward physical modelling of larger prototypes triggers a move towards expansion of the current capability of dynamic centrifuge tests. In this paper a method based on the concept of two-stage scaling is proposed that allows expanded use of the currently available facilities. In the first stage a prototype is scaled down into an intermediate virtual model based on the scaling relations in a 1g field with a scaling factor of ì (prototype/virtual model). In the second stage this model is scaled down into a physical model using the conventional scaling relations in the centrifugal field with a scaling factor of ç (virtual model/physical model). In this manner, a large scaling factor º ìç (prototype/physical model) can be broken down into the smaller scaling factors ì and ç, and thus the centrifuge model tests can be performed with the smaller scaling factor ç. In effect, the limits in the scaling factor for the currently available centrifuge facilities can be expanded by a factor of ì. Validation of the proposed method is provided by algebraic derivations based on the mechanics of model tests.La tendance à la modélisation physique des plus gros prototypes demande d'élargir la capacité actuelle des essais dynamiques centrifuges. Dans cet exposé, nous proposons une méthode basée sur un concept de réduction en deux temps qui permet une utilisation expansée des installations existant actuellement. Dans un premier temps, le prototype est réduit en un modèle virtuel intermédiaire basé sur la relation d'échelle dans un champ 1g avec facteur de ì (prototype/modèle virtuel). Dans un second temps, ce modèle est réduit en un modèle physique utilisant les relations d'échelle conventionnelles dans le champ centrifuge avec facteur de ç (modèle virtuel/modèle physique). De la sorte, un facteur élevé º ìç (prototype/modèle physique) peut être décomposé en facteurs d'échelle plus petits ì et ç si bien que les essais de modèle centrifuge peuvent être faits avec le facteur le plus petit ç. En fait, les limites du facteur d'échelle pour les installations centrifuges existantes peuvent être étendues d'un facteur de ì. La validation de la méthode proposée est donnée par des dérivations algébriques basées sur les mécaniques des essais du modèle.

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The shaking table test and the seismic response analysis of the pier with vertical pile which had arranged the isolation system were done as a technology which improved pier with vertical pile's earthquake resistant ability.It has been understood that the earthquake resistant ability of the seismic isolation pier is better compared with the conventional pier. The analytical method on this study was able to forecast the effect of the seismic isolation quantitatively.For future research, we will investigate the earthquake resistant ability of an actual seismic isolation pier in detail in consideration of the influence of the foundation ground based on the result achieved for this research.

We have proposed highly efficient microcavity second harmonic generation devices. In this work, we designed and fabricated an a-plane GaN vertical monolithic microcavity second harmonic generation device pumped with a femtosecond laser and obtained normalized wavelength conversion efficiency of 0.15% W−1. The efficiency was comparable to the theoretical estimations taking into account time evolution of fundamental wave intensity in the microcavity, second harmonic generation and even sum frequency generation. This result indicates the possibility of realizing ultra-compact and ultra-efficient devices pumped with long-pulsed or continuous wave lasers, in which the effect of resonance enhancement is even more pronounced.