When cavitaiton bubbles collapse violently, local high-temperature high-presure pots are generated, which can be used for various chemical reactions, I.e.,conochemistry. It is necessary to control a sound field in order to generate these spots efficiently. We report two exprimental studies: (1) Observation of a single bubble dynamics in ultrasonic field using a stroboscope and light scattering techinique. (2) Amplitude and frequency dependence of the reaction rate of a model chamical reaction with multu bubble conditons.

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In order to investigate the dggect of needle lift on the early tage of spray desintegration, simultaneous measurments of velocity and size of droplets were conducted by a mewly developed laser 2-focus velocimeter (L2F). The micro-scale prove is consisted of two foci tiwh a distance of 30u.m. The tested nozzle has single hole with a diameter D of 0.2 mm. The measurements of injection pressure, needle lift, and crank angle were synchronized with the L2Fmeasurements, It is clearly showm that droplets are desintegrated remarkably on the transient needle opening condition, Droplets with higher velocity and larger size than the breakup criteria are observed near the spray center on the full nedle lift condition. It is understood that large droplets penetrate along the spray axis and small droplets scatter radially near the nozzle exit.

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The studies of the organismal muotiphase flow have been expected for the applications such as the flow in a drag delivery system and the micro TAS for the blood. Only few studies for the characteristics of the organismal multiphase flow in the micro channel have been done. The actuial organismal fluids is so complexity that the study has large difficulty. The physical and chemical properties of a membrane of the liposome can be assumed as same as the cell membrane. So that, the fluid with the liposomes is presumed as a quasi-organismal multiphase flow. It is simpler than the actual organismal fluid. In this paper, we measured the pressure loss of the multiphase flowwith the liposomes in a micro channel which has the trapezoidal cross section with 40um in top width, 54.74 in oblique angle and 20um in height. Two type of the micro channel are used in the experiments. One is the channel with a hudrophobic wall surface which is modified by the self assembled polymer monolayer (SAM) and anther one os the channel with hydrophilic wall surface made of SiO2. We discessed the characteristics of the multiphase flow with the liposomes in a micro channel.

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