氯化亚汞声光器件换能器五层结构设计

提出用环氧树脂聚合物作为缓冲层 ,设计氯化亚汞声光器件的换能器。从器件的布喇格带宽出发 ,设计了五层结构的换能器 ,计算了以Ag为电极 ,ln或pb粘接层时 ,其五层的各自厚度 ,并确保了换能器倍频程带宽     

Tennessee Promise: A Response to Organizational Change

Community colleges in Tennessee, either directly or indirectly, experienced unprecedented change as a result of Tennessee Promise. The present study explored how student support service administrators at three community colleges responded to organizational change as a result of the Tennessee Promise legislation. Investigators selected community colleges for the multi-site case study because the legislative impact would be actualized by the preparations made to serve incoming Promise recipients. The delivery of orientation services framed organizational change because the service staff facilitate connections and provide information to incoming students. Challenges like a shifting population, ill-equipped infrastructure, inadequate remediation support, heightened interest for social engagement opportunities, misinformation, and unmet fiscal needs left administrators seeking coherence through the change process. Investigators found community college administrators react to change similarly. Administrators acknowledged change as continuous, created a culture of innovation among stakeholders, and were not afraid to fail as responses to the organizational change phenomenon.     

Social facilitation of drinking of a partially satiated duckling

Water-deprived and nondeprived ducklings were reintroduced to a flock companion which had been allowed to partially satiate itself after 3 h of water deprivation. The drinking and sieving behavior of the partially satiated “reactor” bird was immediately increased above that of similar birds left on their own. However, whether or not the introduced “actor” ducklings were deprived had no consequences for the drinking response of the reactor above that obtained by their introduction. The number of companions introduced also failed to have any effect other than that obtained by their introduction. The increase in sieving was greater when deprived, rather than nondeprived, actors were introduced. These results were discussed in relation to the motivational aspects of sieving behavior and the mechanism of social facilitation.     

An Analysis of Peer Feedback Exchanged in Group Supervision

The authors examined the peer feedback exchanged in 2 supervision groups of counselors‐in‐training (CITs). CITs generated 169 statements grouped into 10 clusters representing 5 regions of peer feedback: counselor focus and engagement, insight‐oriented skills, exploratory skills, therapeutic alliance, and intervention activities. Both positive and corrective peer feedback was exchanged on topics ranging from counselor performance skills to case conceptualization.     

The characteristics and perceptions of teachers engaged in leading professional communities

Following educational reform in Israel, teacher-leaders create and lead professional development communities (PDCs), which are professional learning communities with a focus on in-service professional development and/or improving pedagogical effectiveness. Interviews with 30 teacher-leaders and all four district-level program coordinators revealed that, prior to assuming the role, teacher-leaders developed their professional and leadership skills largely in a self-directed manner. They described their PDCs as cohesive and dedicated, cooperative, involving peer-learning, and as creating a knowledge bank of teaching methods and tools. PDCs enable teachers to advance projects within the school and affect school culture. Principals’ involvement with PDCs varied, with their usually considerable involvement very favorably regarded. This article describes these findings and discusses their implications for the professional development of teachers in the international context.     

A Study on the Impact of GPA on Perceived Improvement of Higher‐Order Cognitive Skills*

Colleges of Business (COBs) have experienced high growth rates in the past decade and many colleges are imposing minimum grade point average (GPA) requirements for students to enter or remain in the college. A primary reason for this requirement may be the belief that students with high GPAs are more inclined to demonstrate higher‐order cognitive skills (HOCS) than students with low GPAs. It is not clear whether the link is valid. This study hypothesizes that students with high GPAs who are taught in the same way as students with lower GPAs will have higher perceptions of improved HOCS. We conducted an experiment in which students, with varying GPAs, at three large universities primarily used multimedia instructional materials. We obtained the students' perceptions of their improved HOCS from their responses to a survey. A regression analysis of the data reveals that the relationship between GPAs and students' perceived improvement in HOCS is significant (p < .001). We conclude the study by recommending that (a) it is critical to use research methodologies to evaluate perceived and actual learning improvements, (b) COB policies to implement GPA restrictions on admission are worthwhile, and (c) case studies need to be used much more frequently in undergraduate COB classes.