Transient hot-electron effect and its impact on circuit reliability

Transient hot-electron effect and its impact on circuit reliability are investigated. The rate of device decay is monitored as a function of the gate pulse transient period. Simulation results reveal that excess charges during a fast turn off time may cause an increase in the maximum substrate current. This, along with our experimental data, identifies that transient excess carrier may cause the enhancement of device degradation under certain stress conditions. The enhancement factor of the degradation is a function of the gate pulse transient time. Correlation between the analysis based upon AC/DC measurement and calculations based upon transient simulation are shown in the paper. Better agreement with experimental data is obtained by using the transient analysis and on chip test/stress structures. The correlation between AC and DC stress data is also shown based on the impact ionization model. A hot-electron design guideline is proposed based on the circuit reliability analysis. This guideline can help improve the circuit reliability without adversely effecting the circuit performance.     

Nuclear Magnetic Resonance Studies of Silicon Carbide Polytypes

The ²⁹Si MAS NMR spectra of the 2H, 4H, 6H, and 3C polytypes of silicon carbide are presented. An attempt is made to correlate differences in the chemical shifts with local atomic environment. The results of the analysis of the spectra of pure polytypes are used as a basic for the interpretation of the spectra of mixed polytypes and a discussion of the crystallinity and impurity levels of different samples. Carbon-13 chemical shifts obtained from spectra of the same polytypes are also tabulated.     

Rapid assessment of infant predictors of adult IQ: Midtwin-midparent analyses.

Assessed infant predictors of adult IQ with same-sex infant twins (114 pairs) and their parents. The midtwin–midparent design permits the rapid assessment of infant measures to predict later behavior, because the midparent score serves as a proxy for the infant's potential score at maturity. At 5, 7, and 9 mo, Ss were observed on the Fagan Test of Infant Intelligence, hand preference, vocalizations, selected Bayley Scales of Infant Development items, and a modified Bayley Infant Behavior Record. At 8 mo, Ss received the Visual Expectation Paradigm and an auditory discrimination task. Their parents received the Wechsler Adult Intelligence Scale—Revised (WAIS—R). Some infant measures, indicative of information processing, language ability, and temperament, predicted midparent IQ. This study extended and partially replicated findings from a previous midtwin–midparent cohort (L. F. DiLalla et al; see record 1991-04066-001). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of crystallinity on PVC physical properties

Crystallinity in PVC contributes significantly to the strength and resiliency of the polymer. Two types of crystallites have been described: a primary crystallite in the virgin powder state pictured as a platelet or flat needle-like lamellar crystallite, and a secondary, fringed micellar crystallite from melts or solutions. Both crystallites create loose, crosslinking networks. The secondary crystallite forms when plastisol melts are cooled or solutions are gelled. Crystallites exert a major effect on rheological properties. The thermal destruction of the primary crystallite networks in the melt phase results in a decrease in elastic modulus. Cooling from the fused state creates secondary crystallites that affect tensile and elongation.     

Taconite Pellets in the Blast Furnace

A summary of a ten-year test program utilizing pilot-plant taconite pellets in experimental and commercial blast furnaces, this paper presents operating data and results of this program, as well as results obtained in recent years with commercial taconite pellets.     

Hypothermic coagulopathy in trauma: effect of varying levels of hypothermia on enzyme speed, platelet function, and fibrinolytic activity

Comparative study of protein metabolism in neurons of layers III and V of the sensorimotor cortex was carried out in two groups of Wistar rats, which differed in learning results: "bad" (60% of population) and "good" learners (40%). It was found out that the associative neurons (layer III) were most sensitive to cognitive load. In "bad" learners, an increase in nuclear and cytoplasmic dimensions and rise in protein concentration and content took place in these neurons, while in the efferent neurons (layer V) the protein content increased only in the cytoplasm. In "good" learners, the cognitive load led to a decrease in all the cytochemical parameters in neurons of the layer III while in the neurons of the layer V the content and concentration of proteins increased both in nuclei and cytoplasm. It is suggested that the character of protein metabolism changes produced by information load can be considered as a reflection of individual peculiarities of cognitive activity, and the extent of cytochemical changes as a reflection of complicity of a cognitive task.     

A new framework for understanding educational digital library use: re-examining digital divides in U.S. schools

Despite their decade of deployment, educational digital libraries have not achieved sustained use in elementary and secondary schools in the United States. Barriers to accessing the Internet and computers have been widely targeted by myriad initiatives, but efforts aimed at bridging this first-level “digital divide” have not led to increased use of the Internet and digital library resources in U.S. classrooms. In fact, such programs have revealed additional divides that affect educators’ use. This paper examines the additional digital divide levels and proposes a new framework for understanding technology innovation in schools that can improve development and outreach approaches by digital library developers.