The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Shivendra Yadav - One of the best experts on this subject based on the ideXlab platform.
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analysis of a novel Metal Implant junctionless tunnel fet for better dc and analog rf electrostatic parameters
IEEE Transactions on Electron Devices, 2017Co-Authors: Sukeshni Tirkey, Dheeraj Sharma, Dharmendra Singh Yadav, Shivendra YadavAbstract:Steep rise in the subthreshold slope, high current driving capability, and negligible ambipolarity are the major prerequisite conditions of tunnel FETs (TFETs) to make it applicable for Analog/RF circuit applications. Along with that, fabrication of physically doped TFETs is a major concern in device technology. In this context, this paper deals with junctionless TFET with a Metal Implanted in the oxide at the source/channel and drain/channel junctions to enhance its ON-current and reduce the ambipolar nature. The Metal introduced at the source/channel junction generates abruptness and brings improvement in subthreshold slope, which increases the current driving capability of the device. Similarly, the Metal Implanted at the drain/channel junction widens the energy gap at the same junction to reduce the ambipolar behavior of the device. This also contributes to the enhancement of dc and analog/RF performance of the device. The selection of appropriate work function and length of the Metal Implanted at both the interfaces is important to maintain the improved ON-current and ambipolarity. This optimization gives idea of keeping the appropriate length, which provides direction toward practical feasibility at the experimental level.
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Analysis of a Novel Metal Implant Junctionless Tunnel FET for Better DC and Analog/RF Electrostatic Parameters
IEEE Transactions on Electron Devices, 2017Co-Authors: Sukeshni Tirkey, Dheeraj Sharma, Dharmendra Singh Yadav, Shivendra YadavAbstract:Steep rise in the subthreshold slope, high current driving capability, and negligible ambipolarity are the major prerequisite conditions of tunnel FETs (TFETs) to make it applicable for Analog/RF circuit applications. Along with that, fabrication of physically doped TFETs is a major concern in device technology. In this context, this paper deals with junctionless TFET with a Metal Implanted in the oxide at the source/channel and drain/channel junctions to enhance its ON-current and reduce the ambipolar nature. The Metal introduced at the source/channel junction generates abruptness and brings improvement in subthreshold slope, which increases the current driving capability of the device. Similarly, the Metal Implanted at the drain/channel junction widens the energy gap at the same junction to reduce the ambipolar behavior of the device. This also contributes to the enhancement of dc and analog/RF performance of the device. The selection of appropriate work function and length of the Metal Implanted at both the interfaces is important to maintain the improved ON-current and ambipolarity. This optimization gives idea of keeping the appropriate length, which provides direction toward practical feasibility at the experimental level.
Sukeshni Tirkey - One of the best experts on this subject based on the ideXlab platform.
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analysis of a novel Metal Implant junctionless tunnel fet for better dc and analog rf electrostatic parameters
IEEE Transactions on Electron Devices, 2017Co-Authors: Sukeshni Tirkey, Dheeraj Sharma, Dharmendra Singh Yadav, Shivendra YadavAbstract:Steep rise in the subthreshold slope, high current driving capability, and negligible ambipolarity are the major prerequisite conditions of tunnel FETs (TFETs) to make it applicable for Analog/RF circuit applications. Along with that, fabrication of physically doped TFETs is a major concern in device technology. In this context, this paper deals with junctionless TFET with a Metal Implanted in the oxide at the source/channel and drain/channel junctions to enhance its ON-current and reduce the ambipolar nature. The Metal introduced at the source/channel junction generates abruptness and brings improvement in subthreshold slope, which increases the current driving capability of the device. Similarly, the Metal Implanted at the drain/channel junction widens the energy gap at the same junction to reduce the ambipolar behavior of the device. This also contributes to the enhancement of dc and analog/RF performance of the device. The selection of appropriate work function and length of the Metal Implanted at both the interfaces is important to maintain the improved ON-current and ambipolarity. This optimization gives idea of keeping the appropriate length, which provides direction toward practical feasibility at the experimental level.
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Analysis of a Novel Metal Implant Junctionless Tunnel FET for Better DC and Analog/RF Electrostatic Parameters
IEEE Transactions on Electron Devices, 2017Co-Authors: Sukeshni Tirkey, Dheeraj Sharma, Dharmendra Singh Yadav, Shivendra YadavAbstract:Steep rise in the subthreshold slope, high current driving capability, and negligible ambipolarity are the major prerequisite conditions of tunnel FETs (TFETs) to make it applicable for Analog/RF circuit applications. Along with that, fabrication of physically doped TFETs is a major concern in device technology. In this context, this paper deals with junctionless TFET with a Metal Implanted in the oxide at the source/channel and drain/channel junctions to enhance its ON-current and reduce the ambipolar nature. The Metal introduced at the source/channel junction generates abruptness and brings improvement in subthreshold slope, which increases the current driving capability of the device. Similarly, the Metal Implanted at the drain/channel junction widens the energy gap at the same junction to reduce the ambipolar behavior of the device. This also contributes to the enhancement of dc and analog/RF performance of the device. The selection of appropriate work function and length of the Metal Implanted at both the interfaces is important to maintain the improved ON-current and ambipolarity. This optimization gives idea of keeping the appropriate length, which provides direction toward practical feasibility at the experimental level.
Leon Rybak - One of the best experts on this subject based on the ideXlab platform.
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sparse semac rapid and improved semac Metal Implant imaging using sparse sense acceleration
Magnetic Resonance in Medicine, 2017Co-Authors: Ricardo Otazo, Mathias Nittka, Mary Bruno, Esther Raithel, Christian Geppert, Soterios Gyftopoulos, Michael P Recht, Leon RybakAbstract:Purpose To develop an accelerated SEMAC Metal Implant MRI technique (Sparse-SEMAC) with reduced scan time and improved Metal distortion correction. Methods Sparse-SEMAC jointly exploits the inherent sparsity along the additional phase-encoding dimension and multicoil encoding capabilities to significantly accelerate data acquisition. A prototype pulse sequence with pseudorandom ky-kz undersampling and an inline image reconstruction was developed for integration in clinical studies. Three patients with hip Implants were imaged using the proposed Sparse-SEMAC with eight-fold acceleration and compared with the standard-SEMAC technique used in clinical studies (three-fold GRAPPA acceleration). Measurements were performed with SEMAC-encoding steps (SES) = 15 for Sparse-SEMAC and SES = 9 for Standard-SEMAC using high spatial resolution Proton Density (PD) and lower-resolution STIR acquisitions. Two expert musculoskeletal (MSK) radiologists performed a consensus reading to score image-quality parameters. Results Sparse-SEMAC enables up to eight-fold acceleration of data acquisition that results in two-fold scan time reductions, compared with Standard-SEMAC, with improved Metal artifact correction for patients with hip Implants without degrading spatial resolution. Conclusion The high acceleration enabled by Sparse-SEMAC would enable clinically feasible examination times with improved correction of Metal distortion. Magn Reson Med 78:79–87, 2017. © 2016 International Society for Magnetic Resonance in Medicine
Krishnagoud Manda - One of the best experts on this subject based on the ideXlab platform.
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Modeling of articular cartilage growth around localized defect-filling Metal Implant
Journal of Biomechanical Engineering-transactions of The Asme, 2020Co-Authors: Krishnagoud Manda, Anders ErikssonAbstract:Articular cartilage is a specialized connective soft tissue that resides on the ends of long-bones, and transfers the load smoothly between the bones in diarthrodial joints by providing almost frictionless, wear resistant sliding surfaces during joint articulation. Focal chondral or osteochondral defects in articular cartilage are common and show limited capacity for biological repair. Furthermore, changes in the bio-mechanical forces at the defect site may make the tissue more susceptible to continued degeneration. Alternatively, a contoured focal resurfacing Metal Implant can be used to treat such full-thickness cartilage defects. Physiological and biomechanical studies on animal models with Metal Implant have shown good clinical outcomes. However, the mechanical behavior of cartilage surrounding the Implant has remained largely unanswered with respect to the joint function.First, we developed a simple 3-dimensional finite element model by approximating one of the condyles of a sheep knee joint and parametrically studied the effects of shape, size and positioning of the Implant on the mechanical behavior of the cartilage surrounding the Implant. The mechanical sealing effect due to the wedge shape of the Implant was studied. We also simulated the time dependent behavior of the cartilage surrounding the Implant. In the second part, we developed a more sophisticated model accounting for biological growth aspects of the cartilage around the Implant together with the in vivo mechanical response of the cartilage in an intact human knee joint. An axisymmetric representation of a human knee condyle including both cartilage layers, meniscus and tibia was considered. A cartilage growth finite element model incorporating dynamic loading from walking, which drives the growth stimulation in the cartilage, was developed. Two individually growing constituents in the solid matrix of cartilage together with the biphasic contacts in the joint were considered in the growth model. From our simulations it is evident that the cartilage near the Implant was more stimstimulated, whence the defect edge of the cartilage was growing onto the Implant.The models developed in the present work are simulation tools and have a potential, in relevant aspects, to predict the physiological behavior of the cartilage surrounding the Metal Implant.
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Mechanics and Growth of Articular Cartilage Around a Localized Metal Implant
2020Co-Authors: Krishnagoud MandaAbstract:The purpose of the present study was to develop a model to simulate the articular cartilage growth in an intact knee model with a Metal Implant replacing a degenerated portion of the femoral cartilage. The human knee joint was approximated with a simplified axisymmetric shape of the femoral condyle along with the cartilage, meniscus and bones. Two individually growing constituents (proteoglycans and collagen) bound to solid matrix were considered in the solid phase of the cartilage. The cartilage behavior was modeled with a nonlinear biphasic porohyperelastic material model, and meniscus with a transversely isotropic linear biphasic poroelastic material model. Two criteria (permeation and shear), both driven by mechanical loading, were considered to trigger the growth in the solid constituents. Mechanical loading with sixty heavy cycles was considered to represent daily walking activity. The growth algorithm was implemented for 90 days after Implantation. The results from simulations show that both cartilage layers were more stimulated near the Implant which lead to more growth of the cartilage near the defect. The method developed in the present work could be a powerful technique if more accurate material data and growth laws were available.
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Finite Element Simulations of Biphasic Articular Cartilages With Localized Metal Implants
2020Co-Authors: Krishnagoud MandaAbstract:Recently, physiological and biomechanical studies on animal models with Metal Implants filling full-thickness cartilage defects have resulted in good clinical outcomes. The knowledge of the time-dependent macroscopic behavior of cartilage surrounding the Metal Implant is essential for understanding the joint function after treating such defects. We developed a model to investigate the in vivo time-dependent behavior of the tibiofemoral cartilages surrounding the Metal Implant, when the joint is subjected to an axial load for various defect sizes. Results show that time-dependent effects on cartilage behavior are significant, and can be simulated. These effects should be considered when evaluating the results from an Implant. In particular, the depth into the cartilage where an Implant is positioned and the mechanical sealing due to solidification of the poroelastic material need a time aspect. We found the maximal deformations, contact pressures and contact forces in the joint with time for the Implant positioned in flush and sunk 0.3 mm into the cartilage. The latter position gives the better joint performance. The results after 60 s may be treated as the primary results, reflecting the effect of accumulation in the joint due to repeated short-time loadings. The wedge-shaped Implant showed beneficial in providing mechanical sealing of cartilages surrounding the Implant with time.
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Time-dependent behavior of cartilage surrounding a Metal Implant for full-thickness cartilage defects of various sizes: a finite element study.
Biomechanics and Modeling in Mechanobiology, 2011Co-Authors: Krishnagoud Manda, Anders ErikssonAbstract:Recently, physiological and biomechanical studies on animal models with Metal Implants filling full-thickness cartilage defects have resulted in good clinical outcomes. The knowledge of the time-dependent macroscopic behavior of cartilage surrounding the Metal Implant is essential for understanding the joint function after treating such defects. We developed a model to investigate the in vivo time-dependent behavior of the tibiofemoral cartilages surrounding the Metal Implant, when the joint is subjected to an axial load for various defect sizes. Results show that time-dependent effects on cartilage behavior are significant, and can be simulated. These effects should be considered when evaluating the results from an Implant. In particular, the depth into the cartilage where an Implant is positioned and the mechanical sealing due to solidification of the poroelastic material need a time aspect. We found the maximal deformations, contact pressures and contact forces in the joint with time for the Implant positioned in flush and sunk 0.3 mm into the cartilage. The latter position gives the better joint performance. The results after 60 s may be treated as the primary results, reflecting the effect of accumulation in the joint due to repeated short-time loadings. The wedge-shaped Implant showed beneficial in providing mechanical sealing of cartilages surrounding the Implant with time.
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Finite Element Simulations of Biphasic Articular Cartilages With Localized Metal Implants
Journal of biomechanics, 2010Co-Authors: Krishnagoud MandaAbstract:Articular cartilage is a specialized connective soft tissue that resides on the ends of long-bones, transfers the load smoothly between the bones in di- arthrodial joints by providing almost frictionless, wear resistant sliding surfaces during joint articulation. Focal chondral or osteochondral defects in articular cartilage are common and show limited capacity for biological repair. Fur- thermore, changes in the bio-mechanical forces at the defect site may make the tissue more susceptible to continued degeneration. Alternatively, the con- toured focal resurfacing Metal Implant can be used to treat such full thickness cartilage defects. Physiological and biomechanical studies on animal models with Metal Implant have shown good clinical outcomes. However, the mechan- ical behavior of cartilage surrounding the Implant is not clearly known with respect to the joint function after treating such defects with Metal Implants and also to improve the Implant design. We developed a simple 3-dimensional finite element model by approximating one of the condyles of the sheep knee joint. Parametric study was conducted in the simulations to verify different profiles for the Implant, positioning of the Implant with respect to cartilage surface, defect size and to show the mechanical sealing effect due to the wedge shape of the Implant. We found the maximal deformations, contact pressures and stresses which constitute the mechanical behavior of cartilages. We also confirmed that using a Metal Implant to fill the full thickness chondral defects is more beneficial than to leave the defect untreated from mechanical point of view. The Implant should be positioned slightly sunk into the cartilage based on the defect size, in order to avoid damage to the opposing surface. The larger the defect size, the closer the Implant should be to the flush. We also simulated the time dependent behavior of the cartilages. In all the simulations, a static axial loading was considered. The wedge shape of the Implant provided the mechanical sealing of the cartilage surrounding the Implant. The determined deformations in the cartilages immediately surrounding the Implant are instru- mental in predicting the sticking-up of the Implant into the joint cavity which may damage opposing soft tissues.
Dheeraj Sharma - One of the best experts on this subject based on the ideXlab platform.
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analysis of a novel Metal Implant junctionless tunnel fet for better dc and analog rf electrostatic parameters
IEEE Transactions on Electron Devices, 2017Co-Authors: Sukeshni Tirkey, Dheeraj Sharma, Dharmendra Singh Yadav, Shivendra YadavAbstract:Steep rise in the subthreshold slope, high current driving capability, and negligible ambipolarity are the major prerequisite conditions of tunnel FETs (TFETs) to make it applicable for Analog/RF circuit applications. Along with that, fabrication of physically doped TFETs is a major concern in device technology. In this context, this paper deals with junctionless TFET with a Metal Implanted in the oxide at the source/channel and drain/channel junctions to enhance its ON-current and reduce the ambipolar nature. The Metal introduced at the source/channel junction generates abruptness and brings improvement in subthreshold slope, which increases the current driving capability of the device. Similarly, the Metal Implanted at the drain/channel junction widens the energy gap at the same junction to reduce the ambipolar behavior of the device. This also contributes to the enhancement of dc and analog/RF performance of the device. The selection of appropriate work function and length of the Metal Implanted at both the interfaces is important to maintain the improved ON-current and ambipolarity. This optimization gives idea of keeping the appropriate length, which provides direction toward practical feasibility at the experimental level.
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Analysis of a Novel Metal Implant Junctionless Tunnel FET for Better DC and Analog/RF Electrostatic Parameters
IEEE Transactions on Electron Devices, 2017Co-Authors: Sukeshni Tirkey, Dheeraj Sharma, Dharmendra Singh Yadav, Shivendra YadavAbstract:Steep rise in the subthreshold slope, high current driving capability, and negligible ambipolarity are the major prerequisite conditions of tunnel FETs (TFETs) to make it applicable for Analog/RF circuit applications. Along with that, fabrication of physically doped TFETs is a major concern in device technology. In this context, this paper deals with junctionless TFET with a Metal Implanted in the oxide at the source/channel and drain/channel junctions to enhance its ON-current and reduce the ambipolar nature. The Metal introduced at the source/channel junction generates abruptness and brings improvement in subthreshold slope, which increases the current driving capability of the device. Similarly, the Metal Implanted at the drain/channel junction widens the energy gap at the same junction to reduce the ambipolar behavior of the device. This also contributes to the enhancement of dc and analog/RF performance of the device. The selection of appropriate work function and length of the Metal Implanted at both the interfaces is important to maintain the improved ON-current and ambipolarity. This optimization gives idea of keeping the appropriate length, which provides direction toward practical feasibility at the experimental level.