Publications by authors named "Seonho Seok"

Article Synopsis
  • This study examines how the porosity of neural electrodes affects nerve regeneration and recovery after sciatic nerve injury in rats.
  • Researchers tested two types of electrodes: one with 70% porosity and another with 30% porosity, finding that the higher porosity design led to better nerve regrowth and motor function over five weeks.
  • The results highlight the crucial role of electrode porosity in improving neural interface functionality, suggesting that optimizing this factor could enhance treatments for nerve injuries and neuroprosthetics.
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This paper presents a direct 3D numerical simulation of biaxial surface wrinkling of thin metal film on a compliant substrate. The selected compliant substrate is a commercial Scotch tape on which a gold metal thin film has been transferred by using low adhesion between the thin metal film and polyimide substrate. Compared with the previous fabrication of a cylindrical thin-film wrinkling pattern, an undulated wrinkling pattern has been implemented by increasing the width of the thin metal film in order to create biaxial straining in the thin film.

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This paper presents a 3D direct numerical simulation of buckled thin-film packaging based on transferred elastic thin-film wrinkling bonded on a compliant polymer ring. The mode change of the fabricated thin-film cap is found by measuring the thin-film cap shape at different times after Si substrate debonding. The conventional linear and nonlinear buckling simulations are not adequate to understand the behavior of the thin-film buckling mechanism creating such packaging cap mode change.

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Article Synopsis
  • * The direct simulation incorporates mechanical imperfections in one step, allowing for quicker and less complex modeling while accurately determining key wrinkling parameters like wavelength and amplitude.
  • * Experimental results revealed the elastic moduli for 300 nm thick gold and aluminum films as 250 GPa and 300 GPa, respectively, by comparing experimental data with the simulation outcomes.
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This paper presents the mechanical behaviors of different types of polyimide feedthroughs that are frequently used for implantable polymer encapsulation. Implantable packages of electronic devices often comprise circuits mounted on printed circuit boards (PCBs) encapsulated in a biocompatible polymer material, with input/output feedthroughs for electrical interconnections. The feedthroughs are regarded as essential elements of the reliability of the package since they create inevitable interfaces with the encapsulation materials.

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As fabrication technologies advance, the packaging of MEMS device is being developed in two main directions: MEMS device packaging and MEMS or sensor system integration [...

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This paper proposed and verified the use of polymer-based packaging to implement the chronic implantation of neural interfaces using a combination of a commercial thermal epoxy and a thin parylene film. The packaging's characteristics and the performance of the vulnerable interface between the thermal epoxy layer and polyimide layer, which is mainly used for neural electrodes and an FPCB, were evaluated through in vitro, in vivo, and acceleration experiments. The performance of neural interfaces-composed of the combination of the thermal epoxy and thin parylene film deposition as encapsulation packaging-was evaluated by using signal acquisition experiments based on artificial stimulation signal transmissions through in vitro and in vivo experiments.

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Polymer materials attract more and more interests for a biocompatible package of novel implantable medical devices. Medical implants need to be packaged in a biocompatible way to minimize FBR (Foreign Body Reaction) of the implant. One of the most advanced implantable devices is neural prosthesis device, which consists of polymeric neural electrode and silicon neural signal processing integrated circuit (IC).

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Article Synopsis
  • This paper introduces a textile-based enzymatic biofuel cell designed to harvest energy from glucose in sweat, enabling efficient power management and on-demand energy use.
  • The biofuel cell's output power is enhanced by optimizing electrode size and stacking configurations, achieving a maximum output of 13 μW with a voltage of 0.88 V under specific load conditions.
  • To further increase power levels, a two-staged power management circuit with a buck-boost converter is employed, providing an output voltage of 6.75 V and an efficiency of around 50% at low power levels, while LT-spice modeling validates the circuit's performance.
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This paper presents measurement and FEM (Finite Element Method) analysis of metal adhesion force to a parylene substrate for implantable neural probe. A test device composed of 300 nm-thick gold and 30 nm-thick titanium metal electrodes on top of parylene substrate was prepared. The metal electrodes suffer from delamination during wet metal patterning process; thus, CF plasma treatment was applied to the parylene substrate before metal deposition.

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This paper presents two 2.1-GHz low-phase noise oscillators based on BAW resonators. Both a single-ended common base structure and a differential Colpitts structure have been implemented in a 0.

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