High-speed Schottky-barrier pMOSFET with f/sub T/=280 GHz

High-speed results on sub-30-nm gate length pMOSFETs with platinum silicide Schottky-barrier source and drain are reported. With inherently low series resistance and high drive current, these deeply scaled transistors are promising for high-speed analog applications. The fabrication process simplicity is compelling with no implants required. A sub-30-nm gate length pMOSFET exhibited a cutoff frequency of 280 GHz, which is the highest reported to date for a silicon MOS transistor. Off-state leakage current can be easily controlled by augmenting the Schottky barrier height with an optional blanket As implant. Using this approach, good digital performance was also demonstrated.     

Stress-voiding of narrow conductor lines

The growth of voids in conductor lines that have no applied voltage nor imposed thermal or concentration gradients is examined. Such voids can cause narrow aluminium conductors in silicon ICs to fail spontaneously. Recent attempts to describe void growth mathematically as a stress-driven diffusive phenomenon are reviewed, and an expression for the time dependent void size is derived. The equation is used to explore the many variables of the void-growth problem     

Evidence supporting the formation of 2,3-epoxy-3-methylindoline: a reactive intermediate of the pneumotoxin 3-methylindole

The existence of a cytochrome P450-dependent 2,3-epoxide of the potent pneumotoxin 3-methylindole was indirectly confirmed using stable isotope techniques and mass spectrometry. Determination of hydride shift and incorporation of labeled oxygen in 3-methyloxindole and 3-hydroxy-3-methyloxindole, metabolites that may be in part dependent on the presence of the epoxide, were utilized as indicators of the epoxide's existence. One mechanism for the formation of 3-methyloxindole involves cytochrome P450-mediated epoxidation followed by ring opening requiring a hydride shift from C-2 to C-3. Through incubations of goat lung microsomes with [2-2H]-3-methylindole, the retention of 2H in 3-methyloxindole was found to be 81%, indicating a majority of the oxindole was produced by the mechanism described above. 3-Hydroxy-3-methylindolenine is an imine reactive intermediate that could be produced by ring opening of the 2,3-epoxide. The imine may be oxidized to 3-hydroxy-3-methyloxindole by the cytosolic enzyme aldehyde oxidase. Activities of this putative detoxification enzyme were determined in both hepatic and pulmonary tissues from goats, rats, mice, and rabbits, but the activities could not be correlated to the relative susceptibilities of the four species to 3-methylindole toxicity. The 18O incorporation into either 3-methyloxindole or 3-hydroxy-3-methyloxindole from both 18O2 and H218O was determined. The 18O incorporation into 3-methyloxindole from 18O2 was 91%, strongly implicating a mechanism requiring cytochrome P450-mediated oxygenation. Incorporation of 18O into 3-hydroxy-3-methyloxindole indicated that the alcohol oxygen originated from molecular oxygen, also implicating an epoxide precursor. These studies demonstrate the existence of two new reactive intermediates of 3-methylindole and describe the mechanisms of their formation and fate.     

AMLCD flicker model considering the V/sub T/ shift in a-Si:H TFT

The observed development of flicker with time in active matrix liquid crystal display (AMLCD) panels has been correlated to the threshold voltage shift of the thin film transistors (TFTs) used in panels. The effect of a threshold voltage shift on the panel flicker was calculated using a flicker model developed here. One set of AMLCD panels used for the flicker characterization employed top-gate TFTs, while a second set employed bottom-gate TFTs. Optical measurements to determine the flicker voltage as a function of aging were performed on both types of panels. Electrical characterization of the TFTs extracted the threshold voltage from the C-V measurement. Samples of the TFTs were available on the kerf strips for both panel types, and ensured that the optically characterized panels and the TFTs electrically characterized were manufactured in the same batch for each of the two panel types.     

The Use of Radio-Labeled Drug in Early Dosage form Development to Provide a Relation Between Physical Dosage form Characteristics and Bioavailability

A chemical compound in early drug development was used in its radio-labeled form to provide a relation to the physical dosage form characteristics and bioavailability. The ¹⁴C-labeled compound, a dibenzthiepin acetic acid derivative, was recrystallized in the same manner as the cold compound. A procedure was developed such that the crystal type and size obtained was similar to that of the cold compound. The photomicrographs and specific surface area of both cold and ¹⁴C-1abeled material were equivalent. Capsules, prepared with both cold and ¹⁴C-labeled material, were demonstrated to have equivalent in vitro dissolution profiles.

The capsules containing the ¹⁴C-labeled material were found to be well absorbed when administered to cynomolgus monkeys. Assuming the monkey is a good absorption model for man, this study provided a preliminary assessment of the bioavailability of the compound in man. It also established preliminary control parameters for the raw material and the dissolution of the capsules. These controls would then be used for monitoring capsules intended for early clinical studies.     

An extension of the dehoff growth path analysis

Growth path analysis is discussed from both deterministic and stochastic points of view. If nucleation is assumed deterministic, the number density function is a solution of the continuity equation. If nucleation is considered a stochastic process, the number density function loses its meaning and must be replaced by a probability density function. Im portant implications of stochastic nucleation are discussed.     

The Au-In-Pb system:The AuIn2-In-Pb portion

The Au-In-Pb system was investigated in the AuIn-In-Pb portion of the system. Pb-AuIn and Pb-AuIn₂ quasibinary systems were found:the first, consisting of a eutectic and a monotectic reaction and the second, a eutectic with an inflection in the liquidus. The chief source of information was differential thermal analyses and verification by metallography, X-ray diffraction and microprobe analyses. Four isothermal reactions were found as follows: 1) L₁ ⇌ L₂ + AuIn₂ + AuIn at 433°Celsius 2) L₁ ⇌ Pb + AuIn₂ + AuIn at 316°Celsius 3) Pb + L ⇌ α + AuIn₂ at 172°Celsius 4) α₁ + L ⇌ AuIn₂ + In at 159°Celsius. Verification of these events and the isopleth from 50-50 wt pct Pb-In, a typical solder, to ≈ 47 wt pct Au are given. This work was supported by the United States Energy Research and Development Administration.     

The March issue on instrumentation.

Asserts that technology is available for psychologists to use the small digital computer as a means of generating complex acoustical signals. Artificial speech work is an example of the use of the computer as a digital-to-analog device. Sensory processing research can benefit from this technology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Noninvasive method for the assessment of dermal uptake of pesticides using attenuated total reflectance infrared spectroscopy

Dermal absorption of pesticides is a primary exposure route for agricultural workers, but is not well characterized. Current measurement techniques are either invasive, such as tape-stripping, or require extensive sample preparation or analysis time, such as urinary metabolite monitoring or wipe sampling followed by gas chromatography analysis. We present the application of a noninvasive, spectroscopic approach for the measurement of pesticide absorption into skin. Attenuated total reflectance infrared spectroscopy (ATR-IR) was used to monitor directly the absorption of two pesticides--captan and azinphos-methyl--in ten volunteers over 20 min under occlusive conditions. We found substantial variability in absorption across subjects. Our results were comparable to those measured by the more traditional method of wipe-sampling followed by extraction and gas chromatography analysis. Multivariate data analysis, in the form of multivariate curve resolution (MCR), is a novel addition to this type of experiment, yielding time-resolved information unachievable by standard methods. These data are potentially more informative than the monitoring of blood or urinary metabolites because they can be acquired in essentially real-time, allowing observations of pesticide absorption on a rapid timescale rather than over hours or days.     

Numerical Modeling of Multimaterial Thermoelectric Devices Under Static and Cyclic Thermal Loading

Selection of materials for thermoelectric devices is generally based on a figure of merit that is a function of the Seebeck coefficient, electrical conductivity, and thermal conductivity. While this figure of merit is a useful metric for comparing materials, the relative importance of the constituent properties depends on the particular application and conditions. In addition, multiple materials can be used together to improve the performance or extend the operating range, and determining the performance of such multimaterial combinations requires analysis beyond simply averaging the properties of the constituent materials. In this paper, finite-element numerical simulations under static and cyclic thermal loadings are used to investigate how device performance can be improved by judicious location of the different materials within the device. The results show that the performance of a device with two different materials can be better than that of either of the individual materials. The greatest improvement in performance occurs with cyclic heating, where the overall performance is strongly influenced by the behavior under transient conditions during heating and cooling.