Surface-enhanced resonance Raman scattering (SERRS) spectroscopy was applied to monitor the photopolymerization process of one monolayer (L = 1) of a Langmuir−Blodgett (LB) film of the cadmium salt of a diacetylene monocarboxylic acid derivative, 10,12-pentacosadiynoic acid (DA), prepared on an evaporated silver island film with a mass thickness of 60 Å. The result indicated that the polymerization proceeds in a way that is similar to that of the multilayer LB films (L ≥ 3) of DA prepared on a smooth silver substrate with a mass thickness of 1000 Å, exhibiting a transition from a blue phase (λmax ≈ 635 nm) to a red phase (λmax ≈ 540 nm). In addition, the photopolymerization on the SERS-active substrate with d = 60 Å was found to proceed much faster than that on the smooth (SERS-inactive) substrate (d = 1000 Å). The rate of the photopolymerization of the monolayer on the island film was compared with the rates of a series of LB films of DA prepared on evaporated silver films with d = 60−1000 Å, including the DA Langmuir−Blodgett monolayer sample, into which the spacer layer of LB films of arachidic acid was inserted to control the separation distance between the reacting monolayer and the silver substrate (d = 60 Å). On the basis of these results, we proposed that the enhanced photopolymerization is due to an accelerated propagation reaction (an addition reaction of DA to reactive polydiacetylene oligomers) resulting from an enhanced band-to-band transition of the oligomers caused by a strong coupling of the transition to the localized plasmon resonance of the substrates.

When a thin walled cylindrical liquid storage tank suffers a large seismic base excitation, buckling phenomena such as elephant foot bulge at the bottom portion and nonlinear ovaling vibration at the upper portion shows nonlinearity between the input and response level and suddenly occurs for the excessive input level, thus will be called as “nonlinear ovaling vibration” hereafter in this paper, may be caused. In the 1st report, the elephant foot bulge phenomena and the liquid pressure effects were investigated. In this 2nd report of the series of studies, the effect of nonlinear ovaling vibration phenomena were investigated based on the dynamic buckling tests using scaled models of thin walled cylindrical liquid storage tanks for nuclear power plants. The mechanism and the effect of vertical excitation and liquid sloshing were also studied and discussed.

When a thin walled cylindrical liquid storage tank suffers a large seismic base excitation, buckling phenomena may be caused such as bending buckling at the bottom portion and shear buckling at the middle portion of the tank. However, the dynamic behaviors of the tanks is not fully clarified, especially those from the occurrence of buckling to some failures. In this study, bending buckling phenomena were focused which will be categorized as diamond buckling and elephant foot bulge. As ones of a series of studies, dynamic buckling tests were performed using large scale liquid storage tank models simulating thin walled cylindrical liquid storage tanks in nuclear power plants. The input seismic acceleration was increased until the elephant foot bulge occurred, and the vibrational behavior before and after buckling was investigated. In addition to the large scaled model tests, fundamental tests using small scaled tank models were also performed in order to clarify the effects of dynamic liquid pressure on the buckling threshold and deformation patterns.

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In this paper, we focused on small-bore piping with a diameter less than 4 inches including support equipments on base concrete, with the purpose of verifying a sufficient seismic design margin. The support element tests were designed to obtain the relationship between force and displacement at piping, when the seismic force loaded on piping support equipments consisting of a U-bolt, support element, base plate, anchorage on a base concrete by confirming the behavior of the equipments as it reaches its failure. The support element tests are the part of inelastic seismic test program [1, 2] and aimed to obtain the following basic data on small-bore piping support equipments: • Relationship between force and displacement at piping; • Failure capacity of piping equipments; • Ductility ratio of piping equipments. Our results can be separated into 4 categories based on the relationship between piping force and displacement and failure mode. Tested failure capacity was higher than the designed allowable force for all failure by a factor of 1.5 to 23, indicating a margin of failure capacity. Cantilever support type have a low ductility ratio when there is the snap of expansion anchor or U-bolt and a high ductility ratio when there is significant plastic deformation of the support. Like their cantilever type counterparts, frame support type have a low ductility when there is the snap of expansion anchor and a high ductility ratio when there is significant plastic deformation of the support and U-bolt, even with brittle failure.