Integrated Sensors (United States)

<p>Topology optimization has gained significant attention in the scientific community as a means to automate the design process and explore novel geometries for various applications. In this study, we propose extending this method to the design of motor windings, with a specific focus on coreless electrical machines. These machines offer greater design freedom by eliminating iron teeth that would otherwise restrict the winding design space. Our objective is to optimize the motor winding to maximize the motor constant, a crucial metric balancing motor torque and Joule losses. We present a versatile design method that incorporates a case study but can be adapted to other scenarios. The contributions of this article encompass the adaptation and extension of the density-based topology optimization method for motor windings. Firstly, we propose a multi-coil interpolation scheme that enables the design of a winding pack consisting of multiple coils assembled without restrictions on their final geometry or position. Secondly, we formulate a 2.5-D topology optimization method that allows the coils to overlap in space, avoiding the need for a computationally expensive full 3-D analysis while maintaining reasonable computational time. Our approach yields a novel winding topology featuring tracks of varying width and thickness, resulting in a superior performance with a motor constant increase of up to 17% compared to references.</p>

Neurotransmitters and neuromodulators mediate communication between neurons and other cell types; knowledge of release dynamics is critical to understanding their physiological role in normal and pathological brain function. Investigation into transient neurotransmitter dynamics has largely been hindered due to electrical and material requirements for electrochemical stimulation and recording. Current systems require complex electronics for biasing and amplification and rely on materials that offer limited sensor selectivity and sensitivity. These restrictions result in bulky, tethered, or battery-powered systems impacting behavior and that require constant care of subjects. To overcome these challenges, we demonstrate a fully implantable, wireless, and battery-free platform that enables optogenetic stimulation and electrochemical recording of catecholamine dynamics in real time. The device is nearly 1/10th the size of previously reported examples and includes a probe that relies on a multilayer electrode architecture featuring a microscale light emitting diode (μ-LED) and a carbon nanotube (CNT)-based sensor with sensitivities among the highest recorded in the literature (1264.1 nA μM-1 cm-2). High sensitivity of the probe combined with a center tapped antenna design enables the realization of miniaturized, low power circuits suitable for subdermal implantation even in small animal models such as mice. A series of in vitro and in vivo experiments highlight the sensitivity and selectivity of the platform and demonstrate its capabilities in freely moving, untethered subjects. Specifically, a demonstration of changes in dopamine concentration after optogenetic stimulation of the nucleus accumbens and real-time readout of dopamine levels after opioid and naloxone exposure in freely behaving subjects highlight the experimental paradigms enabled by the platform.

A simple hydrothermal method is utilized to synthesize iron-doped tin oxide nanoparticles (Fe-SnO 2 NPs) at various doping concentrations. The structural characterization using XRD, Raman, and FTIR measurements confirmed the incorporation of Fe ions into the SnO 2 lattice without any deviation in the tetragonal crystal system of SnO 2 nanoparticles. SEM and HRTEM images show the spherical-shaped nanoparticles with agglomeration. The values of interplanar spacing ([Formula: see text]-value) calculated from the HRTEM lattice are consistent with the XRD results. Further, optical analysis revealed a red shift in the optical absorption band and a decrease in the band gap energy with an increase in Fe-dopant concentration. The decrease of PL emission peak intensity with Fe doping revealed the generation of singly charged oxygen vacancies. The H 2 O 2 -assisted photocatalytic degradation efficiency of Fe-SnO 2 NPs investigated against crystal violet dye indicated an efficiency of 98% for 0.05 M Fe-SnO 2 NPs within 30 minutes under visible light illumination. In addition, the effects of pH, scavengers, and reusability of the catalyst are tested. The antibacterial behavior of Fe-SnO 2 NPs against Escherichia coli is examined by using the colony count method, and the inhibition rate was found to be 49, 65, 70, and 78% for pure, 0.01, 0.03, and 0.05 M Fe-SnO 2 NPs, respectively.

More than Moore technologies can be supported by system level diversification enabled by chiplet based integrated systems within multi-chip-modules (MCM) and silicon interposer based 2.5D systems. The division of large system-on-chip dies into smaller chiplets with different technology nodes specific to the chiplet application requirement enables the performance enhancement at system level while achieving lower power consumption. However, these chiplets need to communicate between each other. Routing resources in MCM and 2.5D systems are limited due to system size and thickness restrictions. This work presents energy/bit optimization approach for multi-chip systems with possibility of co-optimization with the routing resources defined by the signalling pitch. Holistic design methodologies are shown which can be further extended by the designer to define the application specific constraints. A detailed analysis of energy per bit relationship to the voltage swing requirement for different topologies is presented along with a specific CML signalling oriented design flow for 2.5D chip to chip interfaces as an example of topology specific optimization possibilities within this methodology.

Influenza virus mutates quickly and unpredictably creating emerging pathogenic strains that are difficult to detect, diagnose, and characterize. Conventional tools to study and characterize virus, such as next generation sequencing, genome amplification (RT-PCR), and serological antibody testing, are not adequately suited to rapidly mutating pathogens like Influenza virus where the success of infection heavily depends on the phenotypic expression of surface glycoproteins. Bridging the gap between genome and pathogenic expression remains a challenge. Using sialic acid as a universal Influenza virus binding receptor, a novel virus avidin-biotin complex-based capture coating was developed and characterized that may be used to create future diagnostic and interrogation platforms for viable whole Influenza virus. First, fluorescent FITC probe studies were used to optimize coating component concentrations. Then atomic force microscopy (AFM) was used to profile the surface characteristics of the novel capture coating, acquire topographical imaging of Influenza particles immobilized by the coating, and calculate the capture efficiency of the coating (over 90%) for all four representative human Influenza virus strains tested.

We present wearable dry electrodes made of silver nanowires for long-term electrophysiological sensing such as electrocardiography and electromyography.

An assembled porous rectangular single crystalline ZnO plate with superior acetone sensing performance and catalytic activity is presented.

Miniaturization of analytical benchtop procedures into the micro-scale provides significant advantages in regards to reaction time, cost, and integration of pre-processing steps. Utilizing these devices towards the analysis of DNA hybridization events is important because it offers a technology for real time assessment of biomarkers at the point-of-care for various diseases. However, when the device footprint decreases the dominance of various physical phenomena increases. These phenomena influence the fabrication precision and operation reliability of the device. Therefore, there is a great need to accurately fabricate and operate these devices in a reproducible manner in order to improve the overall performance. Here, we describe the protocols and the methods used for the fabrication and the operation of a microfluidic-based electrochemical biochip for accurate analysis of DNA hybridization events. The biochip is composed of two parts: a microfluidic chip with three parallel micro-channels made of polydimethylsiloxane (PDMS), and a 3 x 3 arrayed electrochemical micro-chip. The DNA hybridization events are detected using electrochemical impedance spectroscopy (EIS) analysis. The EIS analysis enables monitoring variations of the properties of the electrochemical system that are dominant at these length scales. With the ability to monitor changes of both charge transfer and diffusional resistance with the biosensor, we demonstrate the selectivity to complementary ssDNA targets, a calculated detection limit of 3.8 nM, and a 13% cross-reactivity with other non-complementary ssDNA following 20 min of incubation. This methodology can improve the performance of miniaturized devices by elucidating on the behavior of diffusion at the micro-scale regime and by enabling the study of DNA hybridization events.

Bi-layer Al2O3/HfO2 dielectric RRAM shows reduction in forming voltage compared to single HfO2 layer RRAM device. It was found that Al2O3 dielectric has lower zero-bias activation energy which helps in faster filament growth than HfO2. In addition to low zero-bias activation energy, Al2O3 have lower dielectric constant leading to higher electric field drop in Al2O3 layer. Incorporation of a thin Al2O3 dielectric in HfO2 based RRAMs lowers the forming voltage and increases the Ion/Ioff ratio without sacrificing the physical thickness. Therefore, Al2O3/HfO2 bi-layer dielectric RRAM can be a potential solution for future RRAM which can provide lesser forming voltage and higher Ion/Ioff ratio.