Arsenic deactivation enhanced diffusion and the reverseshort-channel effect

The effect of enhanced diffusion caused by the electrical deactivation of arsenic on the reverse short-channel effect (RSCE) in NMOS devices is investigated. A simple four-mask process was utilized to fabricate deep sub-micron NMOS devices. Source/drain (S/D) implant and anneal conditions were varied in order to determine their implications on the RSCE. Results indicate that when high concentrations of arsenic deactivate, enhanced diffusion occurs, leading to significantly more RSCE. This implies that the dose of the arsenic implant and the subsequent anneals should be carefully considered in source/drain engineering     

The use of residuals in statistical modeling for fatigue-crackgrowth under constant amplitude loading

Various models have been proposed over the years to fit crack growth data. Many papers have appeared in which one or more models are mooted and fitted, and various assessments made of the quality of the fit. At the basic level the data are plotted, together with the fitted curve, to show agreement of experimental and predicted values. In this paper we suggest that it can be useful and informative to go one step further, examining the residuals, i.e., the differences between the experimental and predicted values. We draw attention to certain statistical methods for such critical assessment and show by example that this can reveal deficiencies in fit not otherwise obvious. In this way suitable modifications to the model can be suggested. Additional plots of estimated parameters are also shown to be informative about models     

X-ray topography studies of dislocations in single crystal CVD diamond

X-ray topography has been used to study single crystal diamond samples homoepitaxially grown by microwave plasma-assisted chemical vapour deposition (CVD) on high pressure high temperature (HPHT) and CVD synthetic diamond substrates. Clusters of dislocations in the CVD diamond layers emanated from points at or near the interface with the substrate. The Burgers vectors of observed dislocations have been determined from sets of {111} projection topographs. Dislocations have line directions close to the [001] growth direction and are either edge or 45° mixed dislocations. Where groups of dislocations originated at isolated points they tended to be of the edge variety. Where the substrate surface was deliberately damaged before growth, two sets of dislocations were observed to have propagated from each line of damage and there was a tendency for dislocations to be of the 45° mixed variety with a component of their Burgers vector parallel to the polishing direction. It is demonstrated that X-ray topography can be used to deduce the growth history of CVD synthetic diamond samples produced in multiple growth stages.     

Complex impedance measurements of calorimeters and bolometers: correction for stray impedances

Impedance measurements provide a useful probe of the physics of bolometers and calorimeters. We describe a method for measuring the complex impedance of these devices. In previous work, stray impedances and readout electronics of the measurement apparatus have resulted in artifacts in the impedance data. The technique allows experimenters to find an independent Thevenin or Norton equivalent circuit for each frequency. This method allows experimenters to easily isolate the device impedance from the effects of parasitic impedances and frequency dependent gains in amplifiers.     

Memory for serial position: Effects of spacing, vocalization, and stimulus suffixes.

Several theorists have argued that the magnitude of recency effects in recall reflects the clarity of temporal-order information in memory. Six experiments tested this proposal by observing the effects of three variables (interitem spacing, vocalization, and stimulus suffixes) that can influence the magnitude of the recency effect on memory for serial position. Spacing had no beneficial effects on memory for position. Vocalization benefited memory for position but only at the beginning and end of a list. Stimulus suffixes interfered with memory for position only at the end of a list. The entire pattern of results cannot be explained by temporal-coding accounts of the recency effect. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Imagery for musical timbre.

Subjects made same/different judgments concerning the pitches of two successive tones. In Experiment 1, the two tones were played on either the same instrument (guitar, flute, trumpet) or on different instruments. When the two pitches were indeed the same, people were faster to respond "same" when the instrumental timbres also matched than when two different instruments played the tones. In Experiment 2, the first tone was always a sine wave and the second was one of the same three instrumental tones. Following the sine wave, but before presentation of the second tone, people were asked to form an image of what an assigned instrument would have sounded like playing that pitch. A match between this imagined timbre of the first tone and the timbre of the second tone produced faster reaction times to identical pitches than a mismatch. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Vibrational analysis of high-energy compounds: 1-nitroso-3,3-dinitroazetidine

Abstract

Infrared spectra were obtained and normal coordinate calculations were made for 1-nitroso-3,3-dinitroazetidine (NO-DNAZ) in order to make assignments of the infrared bands to the appropriate normal modes of vibration. Only one stable conformation was found by semi-empirical molecular orbital calculations. Appropriate force constants that had been obtained for TNAZ were used as starting values for NO-DNAZ. The transferability of the force constants was quite good, so they should be useful in calculations for other dinitroazetidines. Force constant refinements resulted in calculated vibrational wavenumbers that differed from observed values by an average of only 1.9 cm^?1.     

Overexpression, purification, and characterization of the cloned metallo-beta-lactamase L1 from Stenotrophomonas maltophilia

OBJECTIVES: The purpose of this study was to assess whether the presence or absence of myocardial viability during dobutamine echocardiography (DE) predicts survival in patients with coronary artery disease (CAD) and severe left ventricular (LV) dysfunction. BACKGROUND: In patients with CAD, the presence of myocardial viability during DE identifies viable myocardium and predicts recovery of LV systolic function after revascularization. However, there is little data on the relation between myocardial viability and clinical outcome in patients with CAD and severe LV dysfunction. METHODS: We studied 318 patients with CAD and a LV ejection fraction (EF) < or =35% who underwent DE and were followed for 18+/-10 months. Patients were classified into four groups. Group I (n=85) consisted of patients who had evidence of myocardial viability and subsequently underwent revascularization. Group II (n=119) consisted of patients with myocardial viability who did not undergo revascularization. Group III (n=30) consisted of patients who did not have myocardial viability and underwent revascularization. Finally, group IV (n=84) patients lacked myocardial viability and did not undergo revascularization. RESULTS: The four groups had similar baseline characteristics and rest LVEF. During follow-up there were 51 deaths (16%). The mortality rate was 6% in group I, 20% in group II, 17% in group III and 20% in group TV (p=0.01, group I vs. other groups). CONCLUSIONS: In patients with CAD and severe LV dysfunction who demonstrated myocardial viability during DE, revascularization improved survival compared with medical therapy.     

Competing risks models for fracture in the ductile to brittle transition temperature region

When fracture toughness testing is carried out over the ductile to brittle transition temperature region cleavage instability may be observed at the initiation of cracking or after some prior ductile crack growth. The amount of precleavage ductile crack growth increases with increasing temperature. At the lower test temperatures, it is possible to assume that all tests will result in cleavage instability. However, as the test temperature increases, at some limiting temperature, the failure mode during the final instability changes from cleavage to ductile. These two different types of behaviour can be accommodated in a statistical analysis which is based on the method of competing risks. A statistical approach is presented for the analysis of data by competing risks and a procedure is given for the estimation of the probability of cleavage failure.