Electron holographic characterization of ultra-shallow junctions in Si for nanoscale MOSFETs

This investigation attempts quantitative characterization of ultra-shallow junctions (USJs) in Si, useful for future generations of nanoscale MOSFETs as predicted by the Semiconductor Industry Association Roadmap. The USJs were fabricated using rapid thermal diffusion (RTD) from a heavily doped n-type surface source onto a heavily doped p-type substrate. The dopant profiles were analyzed using secondary ion mass spectrometry (SIMS), and were further used to calculate the metallurgical junction depth (MJD). One-dimensional (1-D) characterization of the electrical junction depth (EJD) associated with the electrically activated fraction of the incorporated dopants was performed using off-axis electron holography in a transmission electron microscope. 1-D potential profiles were derived from the unwrapped phase of the reconstructed holograms. The EJD was derived from the measured potential distribution across the p-n junction, and quantitative comparison is made with MJD derived from the SIMS profiles. The comparison between calculated electric field and total-charge distributions from the measured potential profiles and the simulated distributions using the SIMS profiles provides a quantitative estimate of the electrical activation of dopants incorporated by the RTD process, within the accuracy limits of this technique, which is discussed herein.     

Surface tension and viscosity of industrial alloys from parabolic flight experiments — Results of theThermoLab project

The surface tension and the viscosity of a series of industrial alloys have been measured by the oscillating drop technique with an electromagnetic levitation device under reduced gravity conditions in several parabolic flights. It was demonstrated that the 20 seconds of reduced gravity available in a parabola were sufficient for melting, heating into the liquid phase, and cooling to solidification of typically 7 mm diameter metallic specimen. The surface tension and the viscosity were obtained from the frequency and the damping time constant of the oscillation which were evaluated from the temperature signal of a highresolution pyrometer. Alloys processed included steels, Ni-based superalloys, and Ti-alloys which were supplied by industrial partners to the project. Three to four parabolas were sufficient to obtain the surface tension and the viscosity over a large range in temperature.     

Constrained image reconstruction for magnetic detection electrical impedance tomography

Magnetic detection electrical impedance tomography (MD‐EIT) produces images of conductivity from magnetic field measurements taken around the body. The ill‐conditioned nature of the MD‐EIT inverse problem is improved by limiting the number of unknowns to be solved. In this article, a method of iterative grid refinement for MD‐EIT, which produces images significantly better than unconstrained solutions, is described. © 2008 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 17, 379–382, 2007     

Grasp preparation improves change detection for congruent objects.

A series of experiments provided converging support for the hypothesis that action preparation biases selective attention to action-congruent object features. When visual transients are masked in so-called change-blindness scenes, viewers are blind to substantial changes between 2 otherwise identical pictures that flick back and forth. The authors report data in which participants planned a grasp prior to the onset of a change-blindness scene in which 1 of 12 objects changed identity. Change blindness was substantially reduced for grasp-congruent objects (e.g., planning a whole-hand grasp reduced change blindness to a changing apple). A series of follow-up experiments ruled out an alternative explanation that this reduction had resulted from a labeling or strategizing of responses and provided converging support that the effect genuinely arose from grasp planning. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of active‐matrix electronic‐ink displays for handheld devices

Abstract— Interest in the use of electrophoretic displays for smart handheld applications has grown tremendously over the past few years. Since the launch of the Philips and E Ink joint development effort in February 2001, material parameters, TFT backplane, electronic hardware and software and modulization skills have been developed to make this promising display concept into a real product. The first commercial launch of active‐matrix electronic‐ink display modules is planned for mid 2004.     

A Systematic Review of Water Vulnerability Assessment Tools

The important relationship between health and water necessitates consideration of water vulnerability. Water vulnerability is contingent upon biophysical and social drivers operating at multiple scales, and is difficult to assess. This paper offers a systematic review of 50 water vulnerability assessment tools. We identify and synthesise the contents of these assessment tools (710 indicators) into five dimensions and 22 sub-dimensions and consider the extent to which they reflect environmental and social aspects. The findings are discussed in light of a holistic approach to water resources management, and specifically Integrated Water Resources Management (IWRM). Significant opportunities exist to enhance the efficacy of water vulnerability assessment tools by incorporating indicators and operational measures for social considerations (e.g., adaptation, institutions, governance) that are developed outside the context of water.     

Zinc deprivation of murine 3T3 cells by use of diethylenetrinitrilopentaacetate impairs DNA synthesis upon stimulation with insulin-like growth factor-1 (IGF-1)

It has been reported that in China, patients with heterozygous familial hypercholesterolemia (FH) may go unrecognized because they do not have xanthomata or premature coronary heart disease and their LDL cholesterol levels are lower than those in their Western counterparts. However, in the Chinese patients in Hong Kong, heterozygous FH appears to manifest in a way similar to that seen in Western countries or Japan. We studied sequence variations in the promoter and coding regions of the 18 exons of the LDL receptor gene in 30 Chinese FH patients. Eighteen mutations were identified in 21 patients scattered in the promoter and 10 exons. Eleven of them were first found in this study. We also found 6 polymorphisms with allelic frequencies different from those in whites but similar to the Japanese, indicating some isolation between white and Oriental populations. A total of 29 mutations in the LDL receptor gene are now known in the Chinese. There is no definite common mutation due to a founder effect. Meanwhile, there were no detectable LDL receptor gene mutations in 9 clinically diagnosed FH patients in whom the R3500Q mutation in apolipoprotein B had also been excluded. The gene defects leading to the FH phenotype in these patients may occur somewhere else in the apolipoprotein B or other related genes, or even in the noncoding sequences of the LDL receptor gene.     

Nasotemporal directional bias of V1 neurons in young infant monkeys

PURPOSE: Optokinetic nystagmus (OKN) in young infants typically shows a temporal-to-nasal asymmetry under monocular viewing conditions. The neural basis for this asymmetry has been a matter of debate. One idea is that the OKN asymmetry reflects a similar asymmetry in the directional sensitivity of primary visual cortical (V1) neurons. An alternative hypothesis is that the OKN asymmetry is due to an immaturity in the ability of cortical neurons to influence the activity of subcortical structures that directly control OKN. We addressed this issue by studying the directional sensitivity of V1 neurons in young infant monkeys. METHODS: The neuronal activity of V1 units was recorded from anesthetized and paralyzed rhesus monkeys ranging in age from 6 days to 8 weeks using standard extracellular single-unit recording methods. For comparison, V1 units from normal adult monkeys were also studied. Using drifting sinusoidal gratings of the optimal spatial frequency and a moderate contrast, we measured the responsiveness of individual units to 24 directions of stimulus movement. The preferred stimulus direction and the magnitude of the directional response bias were determined by a vector summation method. RESULTS: No clear signs of nasotemporal asymmetries in direction tuning were found in our cell population from infant monkeys. However, the overall directional sensitivity and the peak monocular response amplitudes of these units were significantly lower, and binocular suppression was greater during the first 4 weeks of life than in adults. CONCLUSIONS: The OKN asymmetry in young infants may be more closely associated with the lower overall directional sensitivity and the subnormal responsiveness of V1 neurons rather than with an obvious asymmetry in the directional properties of V1 neurons.     

Optimizing an array of antennas for cellular coverage from a high altitude platform

In a wireless communications network served by a high altitude platform (HAP) the cochannel interference is a function of the antenna beamwidth, angular separation and sidelobe level. At the millimeter wave frequencies proposed for HAPs, an array of aperture type antennas on the platform is a practicable solution for serving the cells. We present a method for predicting cochannel interference based on curve-fit approximations for radiation patterns of elliptic beams which illuminate cell edges with optimum power, and a means of estimating optimum beamwidths for each cell of a regular hexagonal layout. The method is then applied to a 121 cell architecture. Where sidelobes are modeled as a flat floor at 40-dB below peak directivity, a cell cluster size of four yields carrier-to-interference ratios (CIRs), which vary from 15 dB at cell edges to 27 dB at cell centers. On adopting a cluster size of seven, these figures increase, respectively, to 19 and 30 dB. On reducing the sidelobe level, the improvement in CIR can be quantified. The method also readily allows for regions of overlapping channel coverage to be shown.