Effect of the gap size on the SSI efficiency of split-gate memory cells

In this paper, new experimental results on the injection efficiency of split-gate memory cells programmed in the source-side-injection mode are reported. It is shown that the gap size has a negligible effect on the cell injection efficiency and, when the read current is not a limiting factor, it can be made large in order to increase the breakdown voltage of the oxide in the gap region, thus enhancing the cell reliability without detrimental effects on the performance. The experimental data is interpreted with the aid of fullband Monte Carlo simulations.     

Combined Treatment with Dif1stat<Superscript>®</Superscript> and Diet Reduce Plasma Lipid Indicators of Moderate Hypercholesterolemia More Effectively than Diet Alone: A Randomized Trial in Parallel Groups

An open-labeled randomized trial with parallel groups was carried out to study the effects of Dif1stat^® (Monascus purpureus–Linear aliphatic alcohols–Niacin) in the treatment of primary moderate hypercholesterolemia. The trial lasted 8 months. The patients, males and females, were assigned to two groups: A (#130), treated with diet, and B (#110) submitted to diet + Dif1stat^®. After 4 months, group A did not show significant changes in Total cholesterol (TC), LDL-cholesterol (LDLC), HDL-cholesterol (HDLC) or non-HDL-cholesterol (non-HDLC). The same group, showed a reduction in TC (–22%), LDLC (–30%) and non-HDLC (–27%) after 8 months (P ≤ 0.001). After 4 months, TC (–21.3%), LDLC (–29%), and non-HDLC (–26%) were significantly lowered in group B (P ≤ 0.001). In group B, TC, LDLC and non-HDLC showed a further reduction after 8 months: –29.4, –38 and –37%, respectively (P ≤ 0.001). Even triglycerides (TG) decreased significantly (–33%) (P ≤ 0.001). After 8 months, group B showed a significant reduction of TG (–33%) (P ≤ 0.001), when compared to group A. Some safety parameters were significantly reduced in both groups: AST and γ-GT in group A after 4 and 8 months, as well as ALT, AST and γ-GT in group B after 8 months (P ≤ 0.001). Dif1stat^®, given with a suitable diet, was well tolerated in the long-term and induced an anti-atherogenic plasma lipid and lipoprotein profile, in patients with moderate hypercholesterolemia.     

Monte Carlo simulation of substrate enhanced electron injection in split-gate memory cells

In this paper, we use fullband Monte Carlo simulations and gate current measurements to investigate charge injection in split-gate memory cells under negative substrate bias. It is shown that, in the source-side-injection (SSI) regime, the enhancement of the programming efficiency due to the substrate bias is low, unless very low drain and floating-gate biases are considered. In particular, the enhancement of the efficiency is largely reduced if the drain current is kept constant when comparing different substrate biases. Furthermore, it is observed that the carrier injection profile under negative substrate bias is broader than in the SSI regime, and a substantial amount of charge is injected in the spacer region.     

Geometric complexity identifies platelet activation in familial hypercholesterolemic patients

Familial hypercholesterolemia (FH), a genetic disease, is associated with a severe incidence of athero‐thrombotic events, related, also, to platelet hyperreactivity. A plethora of methods have been proposed to identify those activated circulating platelets, none of these has proved really effective. We need efficient methods to identify the circulating platelet status in order to follow the patients after therapeutic procedures. We propose the use of computerized fractal analysis for an objective characterization of the complexity of circulating platelet shapes observed by means of transmission electron microscopy in order to characterize the in vivo hyperactivated platelets of familial hypercholesterolemic patients, distinguishing them from the in vivo resting platelets of healthy individuals. Platelet boundaries were extracted by means of automatically image analysis. Geometric complexity (fractal dimension, D) by box counting was automatically calculated. The platelet boundary observed by electron microscopy is fractal, the shape of the circulating platelets is more complex in FH (n = 6) than healthy subjects (n = 5, P < 0.01), with 100% correct classification in selected individuals. In vitro activated platelets from healthy subjects show an analogous increase of D. The observed high D in the platelet boundary in FH originates from the in vivo platelet activation. Computerized fractal analysis of platelet shape observed by transmission electron microscopy can provide accurate, quantitative data to study platelet activation in familial hypercholesterolemia and after administration of drugs or other therapeutic procedures. Microsc. Res. Tech. 78:519–522, 2015. © 2015 Wiley Periodicals, Inc.     

Power Line Communication in Digitally Controlled DC–DC Converters Using Switching Frequency Modulation

This paper investigates power line communication (PLC) in digitally controlled high-frequency switched-mode power supplies in distributed architectures that share the same bus voltage. Communication between different DC-DC converters is obtained by using switching frequency modulation and by detecting the switching signal on the common supply bus voltage. In case of low power transmission, a small duty-cycle perturbation at half of switching frequency is added to enhance the energy of the transmitted signal. Each converter operates at three different switching frequencies: the first is associated with bit 1 transmission, the second is associated with bit 0 transmission, and the third is associated with no transmission state. In the proposed solution, there is no need for an additional power amplifier in order to inject the communication signal on the power lines, but the signal used for the PLC is inherently generated by the pulsewidth modulation of DC-DC converters. Even if aimed at a dedicated digital IC, the communication architecture has been implemented in field-programmable gate arrays. Simulation and experimental results on DC-DC synchronous buck converters confirm that the performance is achievable by the proposed PLC techniques.     

Autotuning of Digitally Controlled DC–DC Converters Based on Relay Feedback

This paper proposes a simple autotuning technique for digitally controlled dc-dc converters. The proposed approach is based on the relay feedback method and introduces perturbations on the output voltage during converter soft-start. By using an iterative procedure, the tuning of proportional-integral-derivative parameters is obtained directly by including the controller in the relay feedback and by adjusting the controller parameters based on the specified phase margin and control loop bandwidth. A nice property of the proposed solution is that output voltage perturbations are introduced while maintaining the relay feedback control on the output voltage. The proposed algorithm is simple, requires small tuning times, and it is compliant with the cost/complexity constraints of integrated digital integrated circuits. Simulation and experimental results of a synchronous buck converter and of a dc-dc boost converter confirm the effectiveness of the proposed solution     

Fully digital hysteresis modulation with switching-time prediction

This paper proposes a digital hysteresis-modulation technique based on switching-time prediction. Sampling controlled variables several times within a switching period, it ensures a dynamic performance comparable to that obtainable with analog hysteresis modulation. Compared to conventional digital hysteresis modulation, it avoids frequency jitter since it predicts switching transitions. Compared to hysteresis modulation based on the detection of the zero crossing of current errors, it avoids external analog circuits. Compared to pulsewidth-modulation (PWM) techniques, it ensures faster dynamic response. These advantages are obtained at the expense of increased signal-processing requirements and of control complexity. Switching-frequency stabilization and synchronization with an external clock can be obtained extending the techniques proposed for analog hysteresis modulations. The proposed predictive algorithm does not require knowledge of load parameters and only a rough estimation of the inductor value, which can be easily self-adjusted. The proposed solution is suited for high-performance current (or sliding-mode) control where the digital hardware has enough computational power to allow multiple samples within a switching period. The proposed modulation technique has been applied to a sliding-mode control of a single-phase uninterruptible power supply (UPS). Experimental results confirm the effectiveness of the proposed approach.     

Derivation of Mount Pinatubo stratospheric aerosol mean size distribution by means of a multiwavelength lidar

A multiwavelength lidar operated in Sodankyla, Finland, during the European Arctic Stratospheric Ozone Experiment (December 1991-March 1992). It produced vertical profiles of stratospheric aerosols at four wavelengths. The determination of aerosol mean size distribution has been performed by use of extinction/backscattering ratios as obtained from lidar data processing at 355, 352, and 750 nm. Lognormal distributions of sulfuric particles with mode radius of r(m) = 0.12-0.25 μm and corresponding widths of s = 2-1.6 have been retrieved as best fits of experimental data, in good agreement with in situ measurements. A successful attempt to derive bimodal log-normal distributions is also described, together with the experimental and theoretical problems involved.     

Parameterization of cloud lidar backscattering profiles by means of asymmetrical Gaussians

A fitting procedure for cloud lidar data processing is shown that is based on the computation of the first three moments of the vertical-backscattering (or -extinction) profile. Single-peak clouds or single cloud layers are approximated to asymmetrical Gaussians. The algorithm is particularly stable with respect to noise and processing errors, and it is much faster than the equivalent least-squares approach. Multilayer clouds can easily be treated as a sum of single asymmetrical Gaussian peaks. The method is suitable for cloud-shape parametrization in noisy lidar signatures (like those expected from satellite lidars). It also permits an improvement of cloud radiative-property computations that are based on huge lidar data sets for which storage and careful examination of single lidar profiles can't be carried out.