TEM Examination of Heart-Treated Nanocrystalline ZnS

Monodisperse, spherical, submicrometer-size ZnS particles with nanocrystalline substructure were heated and examined in situ using a Gatan hot stage and a transmission electron microscope (TEM) at temperatures ranging from 500° to 900°C. The goal of this study was to observe the micro-structural changes that occur in these particles during heat treatment. The particles, whose morphology consists of an agglomeration of nanocrystals, showed significant grain growth and sintering at temperatures as low as 600°C, much lower than expected for bulk ZnS crystals. In addition, the particles were seen to develop hollow cores during heat treatment. This hollowing effect appears to be related to the nanocrystalline/nanoporous nature of the particles.     

Developmental and instructional analyses of children's metacognition and reading comprehension.

Children's understanding of their own cognitive skills, or metacognition, has been hypothesized to play a major role in learning and development. In this study, we examine the developing relation between children's metacognition and reading comprehension. Children in third- and fifth-grade classes were given an experimental curriculum, Informed Strategies for Learning (ISL), designed to increase their awareness and use of effective reading strategies. In both grades, children in experimental classes made significant gains in metacognition and the use of reading strategies compared with children in control classes. The multivariate profiles of reading skills derived from the developmental analyses helped to identify subgroups of children who responded differently to the metacognitive instruction. Although there were specific aptitude-by-treatment interactions, there was a general trend for metacognition and strategic reading to become more congruent from 8 to 10 years of age. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

3D Modeling of electromigration combined with thermal–mechanical effect for IC device and package

This paper studies the numerical simulation method for electromigration in IC device and solder joint in a package under the combination of high current density, thermal load and mechanical load. The three dimensional electromigration finite element model for IC device/interconnects and solder joint reliability are developed and tested. Numerical experiment is carried out to obtain the electrical, thermal and stress fields with the migration failure under high current density loads. The direct coupled analysis and in-direct coupled analysis that include electrical, thermal and stress fields are investigated and discussed. The viscoplastic ANAND constitutive material model with both SnPb and SnAgCu lead-free solder materials is considered in the paper. An IC device is studied to show the modeling methodology and the comparison with previous test data. A global CSP package with PCB is modeled using relative coarse elements. In order to reduce the computational costs and to improve the calculation accuracy, a refined mesh sub-model is constructed. The sub-model technique is studied in a direct and indirect coupled multiple fields. The comparison of voids generation through numerical example in this paper and previous experimental result is given.     

The influence of interphase regions on local thermal displacements in composites

Although the exact physical and chemical mechanisms are not clearly understood, it is widely believed that an interphase region with properties that differ from those of the plain matrix is developed near fiber surfaces in polymer matrix composites. The current study involves experimental investigation and theoretical modeling of the influence of the interphase on local thermal displacements. Experimental studies have centered on the development of a scanning microinterferometer for in-situ measurements of thermal displacements in the interphase. Thermal displacement measurements have been successfully made for specimens containing a single carbon fiber embedded in an epoxy matrix. A three-phase composite cylinder model is adopted to predict the thermal displacements of the single fiber specimen. Comparison of the theoretical displacement predictions with the experimental profiles measured by the interferometer indicate that the value of the matrix properties near the fiber surface differs from the value in the bulk resin. The data provide evidence of the existence of a lower glass transition temperature in the interphase.     

Effects of stress inoculation training on athletes' postsurgical pain and rehabilitation after orthopedic injury.

The efficacy of a cognitive-behavioral intervention ( stress inoculation training; SIT ) for postsurgical anxiety, pain, and physical rehabilitation in injured athletes was tested. Sixty male athletes who underwent arthroscopic surgery for miniscus injury in 1 knee were randomly assigned to either treatment (SIT and physical therapy) or control (physical therapy only) conditions. Results showed that participants in the treatment group demonstrated significantly less postsurgical pain and anxiety during the rehabilitation process, compared with controls. Additionally, treated participants required fewer days to return to criterion physical functioning, compared with nontreated participants. (PsycINFO Database Record (c) 2010 APA, all rights reserved)