Browsing by Subject "Concatenation"

Now showing 1 - 3 of 3

Open Access
Bandwidth improvement in a cMUT array with mixed sized elements
(IEEE, 2005-09) Bayram, Can; Olcum, Selim; Şenlik, Muhammed N.; Atalar, Abdullah
A capacitive micromachined ultrasonic transducer (cMUT) is typically fabricated by concatenation of several cMUT cells with identical physical dimensions. If the membrane thickness is kept fixed, the radius of the cMUT determines the center frequency of operation. A smaller radius implies a greater center frequency. Therefore, it should be possible to put cMUTs with different sizes in parallel to get a larger bandwidth at the expense of gain. In this study, we investigate the optimization of the bandwidth characteristics of a cMUT by using mixed size cells. We designed two mixed size cMUT arrays with a predicted optimized fractional bandwidth value of about 155% at 5.4 MHz, and 146% at 8.8 MHz. These values are about 55% and 58% better than what can be achieved with a uniform size array at the corresponding center frequencies. There is almost no loss in the gain bandwidth product when two different sized cMUTs are used in parallel. There is about 9% increase in gain bandwidth product when three different sized cMUTs are used in parallel. It is shown, in this study, that gain bandwidth product and bandwidth can be enhanced by use of mixed size cMUT cells. © 2005 IEEE.
Open Access
From virtual to physical: Integration of chemical logic gates
(2011) Guliyev, R.; Ozturk, S.; Kostereli, Z.; Akkaya, E. U.
Integration by parts: Advanced information processing at the molecular level requires integrated logic gates, which has to date been possible only virtually. Now, two independently working AND molecular logic gates are brought together by "click" chemistry to form integrated logic gates which respond exactly as predicted from such an integration scheme (see picture, EET=excitation energy transfer).
Open Access
Physical integration of chemical logic gates
(2012) Öztürk, Şeyma
Recent research in molecular logic gates produced molecular equivalence of highly complex digital designs. Advanced data processing at the molecular level requires a considerable degree of integration (concatenation) between molecular logic gates. So far, almost all the integration reported in the literature has been “virtual”, meaning that the outputs at various channels are determined first and then an integrated set of logic gates is proposed to be operating on inputs to produce those outputs. Nevertheless, there is no doubt that at some point there has to be methods to physically connect one molecular logic gate to the other one, for a rational design and implementation. In this study, we synthesized a few derivatives of the well known fluorophore “Bodipy” and then proposed two methodologies to concatenate separately existing and functioning Bodipy-based chemical logic gates. In one instance, we coupled a photochromicity-based AND gate to an ion-responsive Bodipy-based AND gate, making use of the modulation of inner filter effect. In the other example, we coupled two ion-responsive Bodipy-based AND gates through the increased efficiency of energy transfer and “click” chemistry. We are certain that these methodologies are highly promising and our studies are in progress to demonstrate more complex examples of physical integration.