704 research outputs found

    Effects of Parasitics and Interface Traps On Ballistic Nanowire FET In The Ultimate Quantum Capacitance Limit

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    In this paper, we focus on the performance of a nanowire Field Effect Transistor (FET) in the Ultimate Quantum Capacitance Limit (UQCL) (where only one subband is occupied) in the presence of interface traps (DitD_{it}), parasitic capacitance (CLC_L) and source/drain series resistance (Rs,dR_{s,d}) using a ballistic transport model and compare the performance with its Classical Capacitance Limit (CCL) counterpart. We discuss four different aspects relevant to the present scenario, namely, (i) gate voltage dependent capacitance, (ii) saturation of the drain current, (iii) the subthreshold slope and (iv) the scaling performance. To gain physical insights into these effects, we also develop a set of semi-analytical equations. The key observations are: (1) A strongly energy-quantized nanowire shows non-monotonic multiple peak C-V characteristics due to discrete contributions from individual subbands; (2) The ballistic drain current saturates better in the UQCL compared to CCL, both in presence and absence of DitD_{it} and Rs,dR_{s,d}; (3) The subthreshold slope does not suffer any relative degradation in the UQCL compared to CCL, even with DitD_{it} and Rs,dR_{s,d}; (4) UQCL scaling outperforms CCL in the ideal condition; (5) UQCL scaling is more immune to Rs,dR_{s,d}, but presence of DitD_{it} and CLC_L significantly degrades scaling advantages in the UQCL.Comment: Accepted at IEEE Transactions on Electron Device

    HFinFET: A Scalable, High Performance, Low Leakage Hybrid N-Channel FET

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    In this letter we propose the design and simulation study of a novel transistor, called HFinFET, which is a hybrid of a HEMT and a FinFET, to obtain excellent performance and good off state control. Followed by the description of the design, 3D device simulation has been performed to predict the characteristics of the device. The device has been benchmarked against published state of the art HEMT as well as planar and non-planar Si NMOSFET data of comparable gate length using standard benchmarking techniques.Comment: 3 pages, 4 figure

    Fault modeling and parametric fault detection in analog VLSI circuits using discretization

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    In this article we describe new model for determination of fault in circuit and also we provide detailed analysis of tolerance of circuit, which is considered one of the important parameter while designing the circuit. We have done mathematical analysis to provide strong base for our model and also done simulation for the same. This article describes detailed analysis of parametric fault in analog VLSI circuit. The model is tested for different frequencies for compactness and its flexibility. The tolerance analysis is also done for this purpose. All the simulation are done in MATLAB software

    Recovery Time Considerations in Real-Time Systems Employing Software Fault Tolerance

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    Safety-critical real-time systems like modern automobiles with advanced driving-assist features must employ redundancy for crucial software tasks to tolerate permanent crash faults. This redundancy can be achieved by using techniques like active replication or the primary-backup approach. In such systems, the recovery time which is the amount of time it takes for a redundant task to take over execution on the failure of a primary task becomes a very important design parameter. The recovery time for a given task depends on various factors like task allocation, primary and redundant task priorities, system load and the scheduling policy. Each task can also have a different recovery time requirement (RTR). For example, in automobiles with automated driving features, safety-critical tasks like perception and steering control have strict RTRs, whereas such requirements are more relaxed in the case of tasks like heating control and mission planning. In this paper, we analyze the recovery time for software tasks in a real-time system employing Rate-Monotonic Scheduling (RMS). We derive bounds on the recovery times for different redundant task options and propose techniques to determine the redundant-task type for a task to satisfy its RTR. We also address the fault-tolerant task allocation problem, with the additional constraint of satisfying the RTR of each task in the system. Given that the problem of assigning tasks to processors is a well-known NP-hard bin-packing problem we propose computationally-efficient heuristics to find a feasible allocation of tasks and their redundant copies. We also apply the simulated annealing method to the fault-tolerant task allocation problem with RTR constraints and compare against our heuristics

    Underlap Optimization in HFinFET in Presence of Interface Traps

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    In this work, using 3D device simulation, we perform an extensive gate to source/drain underlap optimization for the recently proposed hybrid transistor, HFinFET, to show that the underlap lengths can be suitably tuned to improve the on-off ratio as well as the subthreshold characteristics in an ultra-short channel n-type device without significant on performance degradation. We also show that the underlap knob can be tuned to mitigate the device quality degradation in presence of interface traps. The obtained results are shown to be very promising when compared against ITRS 2009 performance projections as well as published state of the art planar and non-planar Silicon MOSFET data of comparable gate lengths using standard benchmarking techniques.Comment: 5 pages, 8 figures; Accepted in IEEE Transactions on Nanotechnolog

    Foetal umbilical artery doppler versus NST as predictors of adverse perinatal outcome in severe preeclampsia and foetal growth restriction

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    Background: With the advent of electronic foetal monitoring, a relationship between foetal movement and foetal heart rate was observed and that relationship formed the basis for non-stress test (NST). Doppler USG plays an important role in foetal growth restriction (FGR) pregnancies where hemodynamic rearrangements occur in response to foetal hypoxemia. It is now proved that significant Doppler changes occur with reduction in foetal growth at a time when other foetal well-being tests are still normal. This study was done to find out the comparative usefulness of Doppler and NST in the management of FGR and severe preeclampsia and subsequent correlation with perinatal outcome.Methods: This prospective study was conducted on pregnant women with severe preeclamsia and/or FGR beyond 30 weeks of gestation at AHRR Delhi. 50 pregnancies complicated with severe preeclampsia and/or FGR beyond 30 weeks of gestation were selected. Patients meeting the inclusion criteria were subjected to NST. Umbilical arterial Doppler flow was obtained at weekly or twice weekly interval depending on the severity by pulsed wave color doppler indices were measured during foetal apnea by the same examiner at the free loop site where the clearest waveform signal could be visualized. Of 3 measurements, the mean average of S/D ratio was recorded and followed up with serial Doppler assessment and non-stress test. Data was collected and statistical analysis was carried out.Results: The Doppler showed changes earlier than NST giving a significant lead time of up to 20 days with an average of 4.94 days. The UA S/D had the highest sensitivity (88%) and diagnostic accuracy (94%) in predicting the adverse perinatal outcome. The sensitivity and specificity of Doppler as compared to NST was 82.6% and 63.0% respectively with a diagnostic accuracy of 72%. The Doppler has negative predictive value of 80.95% and positive predictive value of 65.5%. Color Doppler has diagnostic accuracy of 72%. The mortality rate in reversal of diastolic flow was 77.77% and in absent UA flow was 16.66%. 12% foetuses were found to have AEDV in UA and among them 66.66% had both FGR+PE as maternal complication. There was 83.33% rate of LSCS, 16.66% neonatal mortality rate, 83.33% NICU stay rate and 66.66% complication rate in neonates. Whereas 18% had REDV and among that 88.88% had both FGR+PE as maternal complication, a similar rate of LSCS, 77.77% rate of neonatal mortality, 100 % NICU stay and 66.66% complication rate in the neonates.Conclusions: Combined foetal testing modalities such as Doppler, NST and biophysical profile provide a wealth of information regarding foetal health. Integrated foetal testing would be ideal for individualized care of the preterm compromised foetuses for timed intervention

    Physicochemical characterization and in vitro dissolution studies of solid dispersions of ketoprofen with PVP K30 and d-mannitol

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    AbstractAim of the present study was to improve the solubility and dissolution rate of poorly water soluble, BCS class-II drug Ketoprofen (KETO) by solid-dispersion approach. Solid dispersions were prepared by using polyvinylpyrrolidone K30 (PVP K30) and d-mannitol in different drugs to carrier ratios. Dispersions with PVP K30 were prepared by kneading and solvent evaporation techniques, whereas solid dispersions containing d-mannitol were prepared by kneading and melting techniques. These formulations were characterized in the liquid state by phase-solubility studies and in the solid state by Differential Scanning Calorimetry (DSC), Fourier Transform Infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). The aqueous solubility of KETO was favored by the presence of both carriers. The negative values of Gibbs free energy illustrate the spontaneous transfer from pure water to the aqueous polymer environment. Solid state characterization indicated KETO was present as fine particles in d-mannitol solid dispersions and entrapped in carrier matrix of PVP K30 solid dispersions. In contrast to the very slow dissolution rate of pure KETO, dispersions of drug in carriers considerably improved the dissolution rate. This can be attributed to increased wettability and dispersibility, as well as decreased crystallinity and increase in amorphous fraction of drug. Solid dispersions prepared with PVP K30 showed the highest improvement in dissolution rate of KETO. Even physical mixtures of KETO prepared with both carriers also showed better dissolution profiles than those of pure KETO

    Synthesis, SAR and antibacterial activity of hybrid chloro, dichloro-phenylthiazolyl-s-triazines

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    AbstractA series of hybrid novel chloro (1a–9a) and dichloro (10b–18b) phenylthiazolyl-s-triazine were synthesized and subsequently subjected to their antibacterial activity against three gram positive viz. Lactobacillus casei (NCIM-2651); Bacillus cereus (NCIM-2458); Staphylococcus aureus (NCIM-2120) and three gram negative viz Salmonella typhimurium (NCIM-2501); Escherichia coli (NCIM-2065); Klebsiella aerogenes (NCIM-2098). The SAR studies around the lead compound revealed that introduction of electron withdrawing groups and amino (–NH–) and mercapto (–S–) linker bridge seemed more promising towards antibacterial activity. Moreover, the virtual Molinspiration screenings are in compliance with Ghose’s rule
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