• JSTS:Journal of Semiconductor Technology and Science
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• v.6 no.4
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• pp.293-298
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• 2006

Thermopiezoelectric method, using poly silicon heater and a piezoelectric sensor, was proposed for writing and reading in a probe based data storage system. Resistively heated tip writes data bits while scanning over a polymer media and piezoelectric sensor reads data bits from the self-generated charges induced by the deflection of the cantilever. 34${\times}$34 array of thermopiezoelectric nitride cantilevers were fabricated by a single step wafer level transfer method. We analyzed the noise level of the charge amplifier and measured the noise signal. With the sensor and the charge amplifier 20mn of deflection could be detected at a frequency of 10KHz. Reading signal was obtained from the cantilever array and the sensitivity was calculated.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.5
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• pp.495-501
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• 2013

This paper describes a flexible wireless telemetering system using a mesoscale cantilever sensor, which is microfabricated with a patterned thin Ni-Cu foil on a resin substrate. The dynamic validation of the sensor has been conducted in a flow. The wireless telemetry is used to obtain data regarding the oscillating flows. It is shown that the sensor is nearly independent of the environmental temperature and is suitable for application to primary healthcare and diagnostic devices. It can be easily integrated with other modules for measuring physiological parameters, e.g., blood pressure, oxygen saturation, and heart rate, to increase the convenience and reliability of diagnosis. The precision and reliability of the sensor are also dependent on the design of the analog front-end and noise reduction techniques. It is shown that the present system's minimum interval between packet transmissions is ~16 ms.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.11
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• pp.743-748
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• 2017

For diseases that are difficult to detect by conventional imaging techniques, the development of a diagnostic method that allows sensors to be inserted into the human body to aid the diagnosis of local spots of the target tissue, is highly desirable. In particular, it is extremely difficult to determine whether vulnerable plaque can later develop into atherosclerosis using only imaging techniques. However, vulnerable plaques are expected to have slightly different mechanical properties than healthy tissue. In this study, we aim to develop a piezoelectric cantilever-type sensor that can be inserted into the human body and can detect the local mechanical properties of the target tissue. A piezoelectric polymer composite based on $BaTiO_3$ nanoparticles was optimized for fabrication of a piezoelectric cantilever. Next, a micro-cone tip was fabricated at the end of the piezoelectric cantilever by thermal drawing. Finally, stiffness of biological tissue samples was measured with the piezoelectric cantilever sensor for verifying its functionality.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2006.10a
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• pp.198-201
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• 2006

In this paper, we fabricated drag force type and pressure difference type gas flow sensor with dry etching technology which used Deep RIE(reactive ion etching) and etching stop technology which used SOI(silicon-on-insulator). we fabricated four kinds of sensor, which are cantilever, paddle type, diaphragm, and diaphragm with orifice type. Both cantilever and paddle type flow sensors have similar sensitivity as 0.03mV/V kPa. Sensitivity of the fabricated diaphragm and diaphragm with orifice type sensor were relatively high as about 3.5mV/V kPa, 1.5mV/V kPa respectively.

• Journal of Sensor Science and Technology
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• v.19 no.3
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• pp.214-220
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• 2010

Three-dimensional(3D) structure of specific DNA can be changed between two conformations under an external environmental transition such as pH and salt concentration variations. We have experimentally observed the conformational transitions of i-motif DNA using AFM cantilever bioassay. It is shown that pH change of a solvent induces the bending defleciton change of a cantilever functionalized by i-motif DNA. This indicates that cantilever bioassay enables the label-free detection of DNA structural changes upon pH change. It is implied that cantilever bioassay can be a de novo route to quantitatively understand the conformational transitions of biological molecules under environmental changes.

• Journal of Sensor Science and Technology
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• v.19 no.2
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• pp.112-117
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• 2010

A high-throughput sorting (HTS) system has been designed to separate target particles using a negative dielectrophoretic (n-DEP) force. The system consists of a meso-sized channel and a cantilever-type electrode(CE) array designed to separate a large number of target particles by discerning subtle difference of weight and dielectric material property of the particles. Using the polystyrene beads with various sizes of 10, 25 and $50{\mu}m$, the developed system exhibits high-throughput sorting of about 200 beads/sec and more than 80 % of separation efficiency.

• Journal of Institute of Control, Robotics and Systems
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• v.3 no.4
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• pp.343-349
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• 1997

In a lightly damped cantilever beam, most of the vibration energy is found around natural frequencies. Based on this, a phase delay control for suppressing vibration of the beam is proposed in this paper. This controller is designed to behave like a velocity feedback controller at the frequencies of modes to be controlled. Also, this controller is designed in consideration with uncontrolled modes for robust stability and improving of the sensitivity function of the control system. This phase delay control is applied to vibration suppression of a cantilever beam with a pair of a piezoelectric actuator and a piezoelectric sensor. Experimental results showed that the phase delay control functions efficiently.

• Korean Journal of Materials Research
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• v.17 no.2
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• pp.121-123
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• 2007

Energy harvesting from the vibration through the piezoelectric effect has been studied for powering the wireless sensor node. As piezoelectric unimorph cantilever structure can transfer low vibration to large displacement, this structure was commonly deployed to harvest electric energy from vibrations. Piezoelectric unimorph structure was composed of small stiff piezoelectric ceramic on the large flexible substrate. As there is the large Young's modulus difference between the flexible substrate and stiff piezoelectric ceramic, flexible substrate could not homogeneously transfer the vibration to stiff piezoelectric ceramic. As a result, most piezoelectric ceramics had been broken at the certain point. We measured and analyzed the stress distribution on the piezoelectric ceramic on the cantilever.

• Journal of Sensor Science and Technology
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• v.30 no.3
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• pp.185-189
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• 2021

Herein, we propose a functional polymer cantilever to enhance maturation and contractile force of cardiomyocytes. The proposed cantilever consists of a surface-patterned polymer substrate and silver nanowires (AgNWs). The AgNWs are transferred to the PDMS substrate using conventional molding techniques. This thin metallic surface significantly improves the adhesion of cardiomyocyte on the surface-patterned PDMS with the hydrophobic characteristics. In addition, the use of AgNWs improves the visibility of the conducting PDMS substrate for the observation of cardiomyocyte through an inverted microscope. The AgNWs also assist in synchronizing each cardiomyocyte to maximize its contractile force.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.493-494
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• 2012