System Modeling of a MEMS Vibratory Gyroscope and Integration to Circuit Simulation

Recently, consumer applications have dramatically created the demand for low-cost and compact gyroscopes. Therefore, on the basis of microelectromechanical systems (MEMS) technology, many gyroscopes have been developed and successfully commercialized. A MEMS gyroscope consists of a MEMS device and an electrical circuit for self-oscillation and angular-rate detection. Since the MEMS device and circuit are interactively related, the entire system should be analyzed together to design or test the gyroscope. In this study, a MEMS vibratory gyroscope is analyzed based on the system dynamic modeling; thus, it can be mathematically expressed and integrated into a circuit simulator. A behavioral simulation of the entire system was conducted to prove the self-oscillation and angular-rate detection and to determine the circuit parameters to be optimized. From the simulation, the operating characteristic according to the vacuum pressure and scale factor was obtained, which indicated similar trends compared with those of the experimental results. The simulation method presented in this paper can be generalized to a wide range of MEMS devices111Ysciescopu

System modeling of mems gyroscope for integration to circuit simulation

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System Modeling of a MEMS Vibratory Gyroscope and Integration to Circuit Simulation

Recently, consumer applications have dramatically created the demand for low-cost and compact gyroscopes. Therefore, on the basis of microelectromechanical systems (MEMS) technology, many gyroscopes have been developed and successfully commercialized. A MEMS gyroscope consists of a MEMS device and an electrical circuit for self-oscillation and angular-rate detection. Since the MEMS device and circuit are interactively related, the entire system should be analyzed together to design or test the gyroscope. In this study, a MEMS vibratory gyroscope is analyzed based on the system dynamic modeling; thus, it can be mathematically expressed and integrated into a circuit simulator. A behavioral simulation of the entire system was conducted to prove the self-oscillation and angular-rate detection and to determine the circuit parameters to be optimized. From the simulation, the operating characteristic according to the vacuum pressure and scale factor was obtained, which indicated similar trends compared with those of the experimental results. The simulation method presented in this paper can be generalized to a wide range of MEMS devices

Multi-porous anion exchange membrane for cationic sample-selective electropreconcentration

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CONTINUOUS LITHIUM EXTRACTION FROM HIGH MG2+/LI+ RATIO BRINE BASED ON ION CONCENTRATION POLARIZATION

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Controlled Production of Monodisperse Polycaprolactone Microspheres Using Flow-focusing Microfluidic Device

These days, biodegradable microsphere polymers have been attracting increasing interest as a cosmetic injectable filler. Particularly, polycaprolactone (PCL) microspheres are well known for their safety and long degradation time. However, these micro spheres are usually produced by the conventional stirring method, which has an inherent drawback related to the size control of the microspheres; accurate size control is critical for the use of these microspheres as a filler. Here, we demonstrate the fabrication of monodisperse PCL microspheres in the size range of 26.6161 tm using a flow-focusing microfluidic device. The acquired coefficient of variation of the solidified microspheres is approximately 4.5%; thus, these micro spheres meet the requirement of being monodisperse. The study results show the feasibility of manufacturing PCL microspheres using a microfluidic device, and these microspheres have better morphological characteristics, thereby reducing pain and infection after their injection into the skin. Furthermore, the specific target size of the solidified microspheres is met. Therefore, undesired outcomes after microsphere injection through the dermis, such as phagocytosis and inflammatory reactions, are less likely to occur.11sciescopuskc

An on-demand micro/nano-convertible channel using an elastomeric nanostructure for multipurpose use

Recently, nanochannels have been widely adopted in microfluidic systems, especially for biosensing and bio-concentrators. Here, we report an on-demand micro/nano-convertible channel, which consists of a simple configuration of elastic nanostructure underneath a single microchannel. By the degree of pressure applied by a pushrod, the microchannel starts to compress into a size-tunable micro- or nano-porous channel. In this approach, under an electric field, we have successfully derived the electrokinetic characteristics of three different regimes: (1) microchannel regime, (2) microporous regime, and (3) nanochannel regime. Utilizing the practical advantage of the transition between regimes with its low cost and easy integration, we demonstrate the pre-concentration and label-free sensing of DNA using a single on-demand convertible channel. Moreover, we demonstrate an ionic diode by applying asymmetric pressure on the elastic nanostructure to create an asymmetric geometry. We believe that the on-demand convertible channel holds potential for promising applications in bioanalytical and iontronic fields.11Nscopu

Comprehensive Electrokinetic-Assisted Separation of Oil Emulsion with Ultrahigh Flux

Many industries have a significant but largely unmet need for efficient and high-flux emulsion separation, particularly for nanoemulsions. Conventional separation membranes rely on size-based separation mainly utilizing a sieving mechanism plus a wetting phenomenon, resulting in a dramatic trade-off between separation efficiency and separation flux. Herein we address this challenge by adapting electrokinetics to membrane-based separation, using a charge-based mechanism capable of separating even nanoemulsions with a demonstrated separation efficiency of >99% and ultrahigh flux up to 40 000 L/H.m(2). Our device arrests nano-oil droplets, allowing them to coalesce into larger droplets which are then able to be filtered by coarser membranes. This hybrid technology makes electrokinetic-assisted filtration scalable and commercially viable and allows for a better understanding of the multiphysics underlying dynamic separation.11Nsciescopu