利用深掺杂Si所研制的微型流量传感器

使用深掺杂方法在Si材料中掺入Au原子后，其电阻率随温度T的变化关系从主要依赖于T-3/2项的浅掺杂材料变成主要依赖于exp(-E／KT)项的深掺杂材料，从而大幅度地提高了掺金Si材料对温度的敏感性。这样在理论上深掺杂Si材料比浅掺杂Si材料对温度的敏感性提高了约1000倍。对于深掺杂方法制成的微型流量传感器特性的测量证明了以上理论。深掺杂Si材料的应用不但大大提高了微型流量传感器的灵敏度，也大幅度地降低了响应时间。     

Vanguards of Change

Following is the speech presented by the president of the Association for Counselor Education and Supervision at its annual luncheon, which was held on April 3, 2004, during the American Counseling Association National Conference in Kansas City, Missouri.     

A Mother-Daughter Book Club: A Search for Intimacy

This study examines the nature of group interaction and response to texts in an African American, mother-daughter literature discussion group in a predominately White, Midwestern college town. The implications of this research for teachers and librarians include a discussion about the value of community and intergenerational literacy and adolescents’ need to share literacy events with adults from their own racialized group.     

Online graduate students’ perceptions of best learning experiences

The purpose of this study is to examine the perceptions of online master’s students regarding their best learning experiences. The authors surveyed 86 graduate students concerning what helped them learn in the online environment. Results indicate that although graduate students learned using the same technological tools as undergraduates, they desired a deeper level of learning that requires more instructional forethought and planning. Student experiences were consistent with the constructivist theory, and implications for improving teaching based upon the constructivist theory are highlighted.     

Minimizing the Influence of Item Parameter Estimation Errors in Test Development: A Comparison of Three Selection Procedures

In test development, item response theory (IRT) is a method to determine the amount of information that each item (i.e., item information function) and combination of items (i.e., test information function) provide in the estimation of an examinee's ability. Studies investigating the effects of item parameter estimation errors over a range of ability have demonstrated an overestimation of information when the most discriminating items are selected (i.e., item selection based on maximum information). In the present study, the authors examined the influence of item parameter estimation errors across 3 item selection methods—maximum no target, maximum target, and theta maximum—using the 2- and 3-parameter logistic IRT models. Tests created with the maximum no target and maximum target item selection procedures consistently overestimated the test information function. Conversely, tests created using the theta maximum item selection procedure yielded more consistent estimates of the test information function and, at times, underestimated the test information function. Implications for test development are discussed.     

Goodness of Fit Between Children and Classrooms: Effects of Child Temperament and Preschool Classroom Quality on Achievement Trajectories

Research Findings: The purpose of this study was to examine whether child temperament differentially predicted academic school readiness depending on the quality of classroom interactions for 179 Head Start preschoolers. Teachers rated children's temperament as overcontrolled, resilient, or undercontrolled in the fall and reported on children's language/literacy and math skills continuously throughout the year. Observations of classroom emotional and instructional support were conducted in the spring. Results from multilevel models indicated that overcontrolled children (compared to resilient children) made greater math gains in classrooms with higher instructional support, whereas a trend-level effect suggested that undercontrolled children (compared to resilient children) made lower math gains in classrooms with lower emotional support. Results also showed that resilient children's gains in language/literacy were more positively associated with high emotional support than were the scores of overcontrolled children. Practice or Policy: This study adds to prior findings suggesting that overcontrolled and undercontrolled children need special attention in the preschool classroom. Teachers and administrators may want to carefully consider the effect that classroom interactions and instructional techniques have on individual children and attempt to tailor instruction to meet the individual needs of children within classrooms.     

Accessing,Integrating, and Inhibiting Word Meaning in Poor Comprehenders

This study examined three processes crucial to reading comprehension (semantic access, integration, and inhibition) to identify causes of comprehension impairment. Poor comprehenders were compared to chronological-age controls and vocabulary-age (VA) controls. When listening to homonym primes (“bank”) versus unrelated primes, controls were faster to name pictures related to dominant (money) and subordinate (river) meanings at 250 ms interstimulus interval (ISI) but only showed dominant priming at 1,000 ms ISI, whereas poor comprehenders only showed dominant priming. When listening to subordinately biased sentences ending in homonyms (“John fished from the bank”) versus control sentences, all groups showed priming when naming subordinate (appropriate) pictures at 250 ms ISI: VA controls and poor comprehenders also showed priming when naming dominant (inappropriate) pictures. At 1,000 ms ISI, controls showed appropriate priming, whereas poor comprehenders only showed inappropriate priming. These findings suggest that poor comprehenders have difficulties accessing subordinate word meanings, which can manifest as a failure to inhibit irrelevant information.     

The effect of short-duration sprint interval exercise on plasma postprandial triacylglycerol levels in young men

Abstract

It is well established that regular exercise can reduce the risk of cardiovascular disease, although the most time-efficient exercise protocol to confer benefits has yet to be established. The aim of the current study was to determine the effects of short-duration sprint interval exercise on postprandial triacylglycerol. Fifteen healthy male participants completed two 2 day trials. On day 1, participants rested (control) or carried out twenty 6 s sprints, interspersed with 24 s recovery (sprint interval exercise – 14 min for total exercise session). On day 2, participants consumed a high-fat meal for breakfast with blood samples collected at baseline, 2 h and 4 h. Gas exchange was also measured at these time points. On day 2 of control and sprint interval exercise trials, there were no differences (P < 0.05) between trials in plasma glucose, triacylglycerol, insulin or respiratory exchange ratio (RER). The area under the curve for plasma triacylglycerol was 7.67 ± 2.37 mmol · l^–1.4 h^–1 in the control trial and 7.26 ± 2.49 mmol · l^–1.4 h^–1 in the sprint interval exercise trial. Although the sprint exercise protocol employed had no significant effect on postprandial triacylglycerol, there was a clear variability in responses that warrants further investigation.