粒子在任意势垒中的隧穿：转移矩阵法

本数值研究粒子在任意势垒中的隧穿谱，提出一种有效的研究方法……转移矩阵法。通过与可严格求解情况的比较，证明这种方法不仅具有高精度而且非常可靠。     

粒子在任意势垒中的隧穿:转移矩阵法

本文数值研究粒子在任意势垒中的隧穿谱,提出一种有效的研究方法--转移矩阵法。通过与可严格求解情况的比较,证明这种方法不仅具有高精度而且非常可靠。     

电子-空穴对在势垒隧穿中的纠缠特性分析

分析了电子隧穿简单势垒所产生的电子-空穴对的纠缠特性.基于能级配置的差异,协力纠缠度随势垒高度的变化呈规律性的变化特征.     

相对论电子在一维n重直角势垒结构中的共振隧穿

应用传输矩阵技术，推导出任意ｎ重直角势垒结构中的相对论电子的透射几率及其共振隧穿条件．在δ势极限下，发现当δ势强度满足一定的量子化条件时，所有能量均能发生共振隧穿．这一相对论电子独有的性质普在双势垒结构中首次报道［５］．本文的结果说明这是任意ｎ垒结构的共有性质．     

如何分析隧穿直角势垒的粒子波函数--评褚圣麟先生<原子物理学>在新印本中的一个变动

针对褚圣麟先生《原子物理学》课本§3.5量子力学问题的几个简例中所存在的问题进行讨论,提出 了改进意见。     

纳米MOS器件栅氧化层电子直接隧穿——量子力学教学中的“生长点”

针对量子力学势垒隧穿教学难点,通过对MOS结构栅氧化层电子直接隧穿的真实模型的讨论,使量子力学从抽象走向实际,教学更生动又易于理解,同时使学生开拓眼界、活跃思维,学到运用基础理论指导科学研究的方法。     

单钢保温管道S形铺设分析的传递矩阵法

单钢保温管道实施S形铺设时,弯曲刚度因混凝土配重层损伤而变化,若要准确分析管道现场接头位置的钢管层应力,就需要考虑管道配重段因弯曲损伤而产生的刚度折减。本文基于混凝土损伤塑性模型,应用有限元法分析弯曲过程中单钢保温管道混凝土配重层的拉伸开裂与压缩破碎,并用与钢管层曲率相关的无因次刚度比表征因配重层损伤导致的管道刚度变化。应用传递矩阵法,结合管道在托管架上的曲率变化,计算铺设管道现场接头位置的附加弯矩,作为现有铺管分析的非线性修正。提出了单钢保温管道S形铺设的上限刚度和下限刚度概念,并与混凝土配重层损伤程度关联,作为该种类型管道铺设刚度控制的基本准则。     

六质点链中的质点关联

讨论了一维六质点系统在弹性内力作用下的质点—质点关联．确定出各个简正频率下系统的内部运动特征     

Radio frequency heating: a potential method for post-harvest pest control in nuts and dry products

The multi-billion dollar US tree nut industries rely heavily on methyl bromide fumigation for postharvest insect control and are facing a major challenge with the mandated cessation by 2005 of its use for most applications. There is an urgent need to develop effective and economically viable alternative treatments to replace current phytosanitary and quarantine practices in order to maintain the competitiveness of US agriculture in domestic and international markets. With the reliable heating block system, the thermal death kinetics for fifth-instar codling moth, Indianmeal moth, and navel orangeworm were determined at a heating rate of 18℃/min. A practical process protocol was developed to control the most heat resistant insect pest, fifth-instar navel orangeworm, in in-shell walnuts using a 27 MHz pilot scale radio frequency (RF)system. RF heating to 55℃ and holding in hot air for at least 5 min resulted in 100% mortality of the fifth-instar navel orangeworm. Rancidity, sensory qualities and shell characteristics were not affected by the treatments. If this method can be economically integrated into the handling process, it should have excellent potential as a disinfestation method for in-shell walnuts.     

Understanding barriers to parent involvement in Head Start: a research-community partnership

The present study was conducted by a research institute, The NCJW Center for the Child, in partnership with two Head Start agencies in New York City. The research grew out of practitioners’ concerns about parent involvement in their programs and what barriers may be inhibiting participation. Sixty-eight mothers whose children had completed one year of Head Start were interviewed using the Barriers to Parent Involvement Survey. Results revealed that mothers reported the presence of many difficult life experiences, but few were reported as actual barriers by many mothers. Five out of 20 of these experiences were associated with staff ratings of mothers’ level of participation. Developing ways to address barriers to participation at the Head Start agencies is discussed in light of the research findings. Information about wider application of the survey as well as research and programmatic implications of the results are included.     

Breaking barriers: The landscape of human and veterinary medical anatomy education and the potential for collaboration

Despite human (HUM) and veterinary (VET) medical institutions sharing the goal of educating future clinicians, there is little collaboration between them regarding curricular and pedagogical practices during the preclinical/basic science training years. This may be, at least in part, due to a lack of understanding of each type of curriculum. This study presents data about curricula, student populations, pedagogical methodologies applied, and anatomy educators' training at both HUM and VET institutions. Preclinical curricula, admissions criteria, and student demographics were analyzed for 21 institutions in the United States having both HUM and VET schools. This dataset was augmented by a questionnaire sent to anatomists internationally, detailing anatomy curricula, pedagogies applied, and anatomy educators' training. Many curricular similarities between both training programs were identified, including anatomy education experiences. However, VET programs were found to include more preclinical coursework than HUM programs. Students who matriculate to VET or HUM schools have similar academic records, including prerequisite coursework and grade point average. Median HUM class size was significantly larger, and the percentage of women enrolled in VET institutions was significantly higher. Training of anatomy educators was identical with one exception: VET educators are far more likely to hold a clinical degree. This study elucidates the substantial similarities between VET and HUM programs, particularly in anatomy education, underscoring the potential for collaboration between both types of programs in areas such as interprofessional education, bioethics, zoonotic disease management, and postgraduate training.     

Second Life in higher education: Assessing the potential for and the barriers to deploying virtual worlds in learning and teaching

Second Life (SL) is currently the most mature and popular multi-user virtual world platform being used in education. Through an in-depth examination of SL, this article explores its potential and the barriers that multi-user virtual environments present to educators wanting to use immersive 3-D spaces in their teaching. The context is set by tracing the history of virtual worlds back to early multi-user online computer gaming environments and describing the current trends in the development of 3-D immersive spaces. A typology for virtual worlds is developed and the key features that have made unstructured 3-D spaces so attractive to educators are described. The popularity in use of SL is examined through three critical components of the virtual environment experience: technical, immersive and social. From here, the paper discusses the affordances that SL offers for educational activities and the types of teaching approaches that are being explored by institutions. The work concludes with a critical analysis of the barriers to successful implementation of SL as an educational tool and maps a number of developments that are underway to address these issues across virtual worlds more broadly.     

Science Letters:Radio frequency heating: a potential method for post-harvest pest control in nuts and dry products

The multi-billion dollar US tree nut industries rely heavily on methyl bromide fumigation for postharvest insect control and are facing a major challenge with the mandated cessation by 2005 of its use for most applications. There is an urgent need to develop effective and economically viable alternative treatments to replace current phytosanitary and quarantine practices in order to maintain the competitiveness of US agriculture in domestic and international markets. With the reliable heating block system, the thermal death kinetics for fifth-instar codling moth, Indianmeal moth, and navel orangeworm were determined at a heating rate of 18℃/min. A practical process protocol was developed to control the most heat resistant insect pest, fifth-instar navel orangeworm, in in-shell walnuts using a 27 MHz pilot scale radio frequency (RF) system. RF heating to 55℃ and holding in hot air for at least 5 min resulted in 100% mortality of the fifth-instar navel orangeworm. Rancidity, sensory qualities and shell     

Examining barriers in technology-enhanced problem-based learning: Using a performance support systems approach

This study focused on the barriers that middle school teachers faced when implementing technology-enhanced problem-based learning (PBL) in their classrooms. Using a human performance-based model, we interviewed teachers, administrators, university faculty and technical support staff to determine the perceived importance of multiple barriers to the implementation of technology-enhanced PBL. Twenty-one teachers, two school administrators and a project manager, two faculty members, and two technical support staff participated in the study. Interview data were supported by surveys, classroom observations and researchers' reflective journals. Results suggested that lack of a clear, shared vision was the primary barrier. Additional barriers included lack of knowledge and skills, unclear expectations and insufficient feedback. Recommendations to support teachers' efforts to integrate technology-enhanced problem-based learning are presented.