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

Case Report: Posterior Ischemic Optic Neuropathy

Purpose: To report on posterior ischemic optic neuropathies, a vascular disorder that happens in the posterior part of the optic nerve and therefore, usually does not present with optic disc edema. Case Report: This is a case report on a posterior ischemic optic neuropathy with an uncharacteristic presentation. It highlights the importance of understanding the different pathophysiology of PION vs anterior ischemic optic neuropathies in order to help differentiate the two clinically and includes a literature review of posterior ischemic optic neuropathy

Rapport de cas : Neuropathie optique ischémique postérieure

La neuropathie optique ischémique postérieure (NOIP) est un trouble vasculaire qui survient dans la partie postérieure du nerf optique et qui, par conséquent, ne se présente habituellement pas avec un œdème du disque optique. Rapport de cas : Nous rapportons ici un cas de NOIP avec une présentation non caractéristique. Ce rapport de cas souligne l’importance de comprendre les différentes physiopathologies de la NOIP et de la neuropathie optique ischémique antérieure (NOIA) pour aider à différencier les deux sur le plan clinique, et comprend une recension des écrits sur la NOIP

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 ion separation via electrokinetic-driven ion migration path differentiation: practical application to lithium extraction from brines

The effective separation of Mg2+ from Li+ is the key for realizing efficient and economic lithium extraction from brine, but remains challenging due to their similar chemical properties. Recent approaches have enabled simultaneous magnesium removal and lithium extraction from high Mg2+/Li+ ratio brines, but their reliance on physical or chemical filters has led to inconsistent performance dependent on brine conditions and corresponding limitations in their cost-effectiveness and scalability. Despite Mg2+'s and Li+'s kindred properties, a subtle difference in their electrophoretic mobilities has allowed for the development of the herein proposed new ion separation method for continuous lithium extraction from high Mg2+/Li+ ratio brines utilizing electrokinetic manipulation of ion migrations. This is the first experimental demonstration of a filterless and force-based ion separation method that works by steering ions onto different paths simply by balancing the diagonally formed electric field intensity and flow rate, and realized by introducing a highly scalable electrokinetic system equipped with a multiscale-porous anion exchange membrane. The effects of core operating parameters as well as brine conditions on system performance are elaborated through experimental studies. Remarkably, consistent performance can be achieved in this system regardless of brine conditions by virtue of the filterless lithium extraction mechanism. This work offers a novel strategy to precisely modulate ion migrations in an aqueous solution and furthers progress toward both active ion manipulation and practical and economic lithium mining from different types of lithium-containing brines.11Nsciescopu

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

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탄성을 가지는 나노구조물을 이용한 다목적 사용자 주문형 마이크로-나노 변신 채널

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