We have studied devices which have been related to chemical process.
We have developed micro reactors, hydrothermal synthesis method and piezoelectric devices using hydrothermal synthesis method.
The emulsification has been an important factor in the fields of food, medical products, cosmetic, chemical and other industries. In the pharmaceutical field, the emulsification can improve a solubility of the medical agent because many medical agents have characteristics that the solubility in water is low and easily dissolve in oil.
In this research, a flow type emulsion formulation generation device which has a T-type microchannel device and an ultrasonic vibration device has been developed. The ultrasonic vibration device can solve the problem of noise by using a high frequency ultrasound.
We have succeeded in generating fine emulsions when the flow rate of the water and oil phase, the driving frequency, and the applied voltage were 100 and 10 ml / min, 2.3 MHz, and 100 Vp-p, respectively. The peak of the oil droplets’ diameter was 200 nm.
Nowadays, the study of the micro chemical process that uses a micro reactor has been activated. Micro reactor is expected to have many advantages such as high reaction speed, mixing efficiency of chemical reactions and simplification of the process which can be achieved simultaneously.
In this study, I have developed a slug flow generation/separation system using micro electromagnetic drive valve. Furthermore, I have proposed a new chemical process “Micro Beaker Process (MBP)”, which will realize very even mixing and reactions.
The micro valve can control slug flow pattern arbitrarily without depending on viscosity of liquids and flow rate by using its big driving force and high response.
As a result of the slug flow generation experiments using water and oil, a system worked well to control the slug pitch from 0.5mm to 4 mm in the channel of 0.5mm in internal diameter. Additionally, I have developed a separation valve using an optical sensor.
Nanoparticles have been receiving attention in many fields such as electronic materials, medicine and so on. In this study, to generate nanoparticles for a chemical process, we have generated mono-disperse droplets in the flowing ambient liquid by using a torsional bolt-clamped Lngevin-type transducer and a micropore plate.
I have designed the droplet generation device by using a finite element method. The micropore is protuberant to prevent liquid from spreading on the micropore's surface. When pure water was used as the dispersed liquid and n-dodecane solution was used as the ambient liquid, we have succeeded in generating mono-disperse droplets in the flowing ambient liquid productively. When the applied pressure of dispersed liquid and the vibrational velocity of the micropore were 0.13MPa and 96.5mm/s, the average diameter of generated droplets and the coefficient of variation were 51.3μm and 3.6, respectively.
As a result, the diameter of droplet can be controlled by the driving frequency of the transducer or the applied pressure of the dispersed liquid.
Recently, minimally invasive surgeries using a catheter are widely performed. Those surgeries need the diagnosis in the tip of the vascular catheter. By using the intravascular ultrasound device (IVUS), the visualization of the blood vessel wall has been realized. However, that for front direction of vessel has not been realized.
In this research, I have fabricated the ultrasonic transducer for IVUS to realize visualization in front direction. PZT films have been deposited by the hydrothermal method. The hemispherical shape ultrasonic transducers which have a radius of 1mm have been fabricated. The directionality of those transducers was evaluated by under water experiment. As a result, the low directionality ultrasonic transducer by using a single element has been achieved.