Very Low Voltage Rail-to-Rail Programmable-Gain CMOS Amplifier

A novel design technique for operating closed-loop amplifier circuits at very low supply voltages is proposed. It is based on the use of quasi-floating gate transistors, avoiding issues encountered in true floating-gate structures such as the initial floating-gate charge, offset drift with temperature, and the gain-bandwidth product degradation. A programmable-gain differential amplifier is designed and implemented following this method. Measurement results of an experimental prototype fabricated in a 0.5-m CMOS technology validate on silicon the proposed technique.     

Low-Power Low-Voltage Class-AB Linear OTA for HF Filters with a Large Tuning Range

This letter presents a new low-voltage class-AB differential linear OTA. The proposed transconductor uses a novel scheme based on two cross-coupled class-AB pseudo-differential pairs biased by a Flipped Voltage Follower [1]. The transconductor has been designed using a 0.8 m CMOS technology to operate at 2 V supply voltage with only 260 W of quiescent power consumption. Simulation results show 90 MHz bandwidth with more than two decades of transconductance tuning range.     

Green Synthesis of Ag-Cu Nanoalloys Using <Emphasis Type="Italic">Opuntia ficus</Emphasis>-<Emphasis Type="Italic">indica</Emphasis>

Bimetallic Ag/Cu nanoparticles have been obtained by green synthesis using Opuntia ficus-indica plant extract. Two synthesis methods were applied to obtain nanoparticles with core–shell and Janus morphologies by reversing the order of precursors. Transmission electronic microscopy revealed size of 10 nm and 20 nm for the core–shell and Janus nanoparticles, respectively. Other small particles with size of up to 2 nm were also observed. Absorption bands attributed to surface plasmon resonance were detected at 440 nm and 500 nm for the core–shell and Janus nanoparticles, respectively. Density functional theory predicted a breathing mode type (BMT) located at low wavenumber due to small, low-energy clusters of (AgCu) _n with n = 2 to 9, showing a certain correlation with the experimental one (at 220 cm^?1). The dependence of the BMT on the number of atoms constituting the cluster is also studied.     

Hierarchical Y and USY Zeolites Designed by Post‐Synthetic Strategies

Strategic combinations of affordable and scalable post‐synthetic modifications enabled to design a broad family of hierarchical Y and USY zeolites (FAU topology) independent on the Si/Al ratio. Pristine (Y, Si/Al = 2.4), steamed (USY, Si/Al = 2.6), and steamed and dealuminated (USY, Si/Al = 15 and 30) zeolites were exposed to a variety of acid (H₄EDTA and Na₂H₂EDTA) and base (NaOH) treatments, which led to the introduction of mesopore surfaces up to 500 m² g^?1, while preserving the intrinsic zeolite properties. Pristine Y and USY zeolites (Si/Al ～ 2.5) required mild dealumination (to Si/Al > 4 in the case of Y) to facilitate subsequent efficient desilication. Alkaline treatment of Y and USY zeolites with low Si/Al ratios (～4–6) led to an abundance of Al‐rich debris, which could be removed by a subsequent mild acid wash. On the other hand, severely steamed and dealuminated, hence Si‐rich, USY zeolites (Si/Al = 15 and 30) proved extremely sensitive to the alkaline solution, displaying facile dissolution and substantial amorphization. For the latter group of ultra‐stable Y zeolites, the presence of TPA⁺ in the alkaline solution enables to protect the zeolite structures upon the introduction of mesoporosity by desilication, preserving crystallinity and micropore volume. The sorption and catalytic properties of the hierarchical Y and USY zeolites were superior compared to the conventional counterparts.     

Bounds on performance for the noisy reference PSK channel

A lower bound is derived for the uncoded error probability of coherent digital phase-shift-keying without making any assumptions on phase-locked loop speed. An improved upper bound on bit error probability is also derived. The results are applicable to both lightwave homodyne detection, in which the laser's phase noise must be taken into account, and to general partially coherent detection of (binary phase-shift-keying) over the additive white Gaussian noise channel when a noisy phase reference is derived. Bit-error-rate and cut-off bounds are presented     

Adaptive Neural Fuzzy Inference System for the Detection of Inter-Turn Insulation and Bearing Wear Faults in Induction Motor

The positive features of neural networks and fuzzy logic are combined together for the detection of stator inter-turn insulation and bearing wear faults in single-phase induction motor. The adaptive neural fuzzy inference systems (ANFISs) are developed for the detection of these two faults. These faults are created experimentally on a single-phase induction motor in the laboratory. The experimental data is generated for the five measurable parameters, viz, motor intakes current, speed, winding temperature, bearing temperature, and the noise of the machine. Earlier, the ANFIS fault detectors are trained for the two input parameters, i.e., speed and current, and the performance is tested. Later, the three remaining parameters are added and the five input ANFIS fault detector is trained and tested. It observed from the simulation results that the five input parameter system predicts more accurate results     

A Novel Architecture for Programmable Fractional-N PLL

In this paper, a novel architecture for programmable fractional-N PLL is proposed. Unlike the conventional fractional-N PLL, it does not need any input data word to meet step size requirement. It features programmability in step sizes. The ratio of the externally controlled counter values sets the step size and thus step size is not limited by fixed hardware. A flow chart is provided to understand the operation of the various counters used in the proposed architecture. A behavioral modeling approach is attempted to perform overall system simulation using Hspice. A 2.4 GHz fractional-N PLL prototype is demonstrated using 0.35 μm CMOS process and test results are provided. It has step sizes of the values of integer multiples of 50 kHz. The main contributions include: (i) Novel architecture, and (ii) Prototype implementation, all for programmable fractional-N PLL. Unlike the most PLLs, the proposed PLL system is amenable to behavioral system simulation using Hspice.     

Gated Mesoporous Silica Nanoparticles Using a Double‐Role Circular Peptide for the Controlled and Target‐Preferential Release of Doxorubicin in CXCR4‐Expresing Lymphoma Cells

B‐cell non‐Hodgkin's lymphoma (B‐NHL) is the most frequent malignant lymphoid neoplasm, which has a high degree of relapse and chemoresistance. Thus, strategies to improve currently used therapies are needed. In this context, a new CXCR4‐targeted delivery system is described using mesoporous silica nanoparticles (MSNs) that are loaded with doxorubicin and capped with a derivative of the T22 peptide (P). This design makes full use of the great affinity of the T22 peptide to CXCR4 receptor, which is overexpressed in lymphoma cells. The peptide is able to guide the gated nanoparticle to B‐NHL cells to facilitate MSNs uptake via the CXCR4 receptor. The endocyted P‐capped MSNs are also opened by endosomal proteolytic enzymes to allow intracellular doxorubicin delivery.     

Outage Capacity for Secondary Users Due to Bandwidth Fluctuations: Multicarrier Versus Single Carrier

In this work we study the channel capacity from the point of view of a secondary user that shares the bandwidth of the channel with a primary user using dynamic spectrum access in cognitive radio.The secondary user sees bandwidth fluctuations (i.e, at any given time the bandwidth can be available or not) that impact its channel capacity. We study the outage capacity for the secondary user considering two scenarios in which the secondary user uses either a single carrier modulation for the case in which bandwidth fluctuates over the complete transmission band, and a multicarrier modulation for the case in which bandwidth fluctuations are over various transmission subbands. We derive expressions for the outage capacity of the secondary user for both single carrier and multicarrier. Results show that: (1) The outage capacity for single carrier can be higher than for multicarrier, but with a higher outage probability for single carrier than for multicarrier. In fact, a low value of outage probability for single carrier requires a duty cycle for the secondary user close to one, but this has the problem that it leaves a very short duty cycle for the primary user. (2) Although for the secondary user the outage capacity for multicarrier is smaller than for single carrier, for multicarrier lower values of the outage probability can be achieved even for short values of the duty cycle of the secondary user, allowing larger duty cycle values of the primary user. (3) For multicarrier, the outage capacity is more sensitive to changes in the duty cycle than to changes in the outage probability. To obtain a larger outage capacity with low values of both the outage probability and the duty cycle, it requires the use of a large number of subbands.     

Dielectric properties of a ceramic oxide: Li(Ni<Subscript>7/10</Subscript>Fe<Subscript>3/10</Subscript>)VO<Subscript>4</Subscript>

The Li(Ni_7/10Fe_3/10)VO₄ compound has been synthesized by solution-based chemical route. Its dielectric response is investigated using complex impedance spectroscopy technique. Frequency dependence of dielectric constant (ε_r) at different temperatures shows low-frequency dispersion due to polarized structure of the material and mobile charge carriers. Temperature dependence of ε_r at different frequencies exhibits the dielectric anomalies in ε_r at different temperatures. Dielectric relaxation process in the material is signified by the variation of tangent loss with frequency at different temperatures. The variation of relaxation time with temperature obeys the Vogel–Fulcher law.