Negative Valve Overlap Mode of HCCI Operation Using Gasoline and Diesel Blended Fuels

The negative valve overlap (NVO) strategy of HCCI operation was experimentally investigated on a gasoline HCCI engine operated with variable valve timing in association with the addition of diesel fuel. The experimental results show that, by using gasoline and diesel blended fuels, the required NVO interval for suitable HCCI combustion under a given engine speed and a moderate compression ratio condition could be reduced, and the HCCI combustion region was extended remarkably without substantial increase in NOx emissions under a given inlet and exhaust valve timing due to the improvement of charge ignitability. In addition, the possible scale of NVO was extended. A substantial increase in the lean limit of excess air ratio and the upper limit of load range can be achieved because of higher volumetric efficiency, resulting from the decrease in the required NVO and the presence of less residual gases in cylinder.     

基因芯片及其应用

基因芯片又称DNA微矩阵，是一种分析大量复杂生物样品的有效工具。它可以通过光引导聚合技术、电压打印或人工直接点样制备。光蚀刻技术可以使探针密度达到10^6／cm^2。它们可以被广泛地应用于DNA序列测定、新基因的检测和突变基因的分析。在医学上，基因芯片可以被用于癌症的诊断，传染病疾病如AIDS和肝炎等的早期检测。它在新药开发上也有巨大的市场。     

Evaluating the Effectiveness of Scientific Visualization In Two PowerPoint Delivery Strategies on Science Learning for Preservice Science Teachers

Slideware applications (e.g., PowerPoint) have become more prevalent in instruction across disciplines. This is especially true at post secondary institutions where many instructors are using slideware as a sole instructional tool. This study evaluated the relative effectiveness of scientific visualization in two PowerPoint delivery strategies on science learning for preservice teachers. Twenty-five preservice teachers enrolled in an undergraduate introduction to science education class were stratified into two PowerPoint delivery strategies. The strategies were: PowerPoint with instructor voiceover narration and PowerPoint without voiceover. Post-test Mann-Whitney U suggested no differences (p > 0.05) in science learning across the two strategies. Further, eye tracking analysis suggests voiceover guides the PowerPoint user to graphics and text, but voiceover does not significantly affect learning. Results suggest immediacy with technology doesn't necessarily produce meaningful learning. Good teaching still is the key component of meaningful learning.     

STUDENTS’ SOURCES OF MOTIVATION FOR PARTICIPATING IN SCIENCE FAIRS: AN EXPLORATORY STUDY WITHIN THE CANADA-WIDE SCIENCE FAIR 2008

Science fairs have been for many years a popular school activity in North America. They are a venue for the popularization of science and consequently an important encouragement for the pursuit of careers in science or engineering. However, little is known about students?? perceived motives for participating in local or national science fairs and about the way in which their involvement mediates their interest in science learning and scientific careers. The present study investigates the motivational factors associated with the high school students?? decision to participate in the 2008 Canada-Wide Science Fair, a thoroughly selected and highly motivated group. Our study examines 5 sources of motivation: (1) interest in science content, (2) sense of self-efficacy, (3) assurance of achievement through rewards or gratifications, (4) the social aspect of participating and (5) working strategies to gain scientific knowledge and methods. The understanding of the anticipated benefits participants seek through their involvement in science fairs may have the potential to help science teachers adapt instruction to appeal to a broader range of students in schools, thus nourishing the emergence of more interest in science.     

浅析建设档案强国的客观必要性

从档案的信息资源属性入手,探讨了档案强国的含义和基本特征,并从满足人民文化需要、推动文化产业发展、传承和弘扬中华民族优秀传统文化、推进社会主义核心价值体系建设四个方面分析了建设档案强国的必要性.其中分析了档案作为文化产品“母资源”的地位与作用,并阐释了其在文化产业发展过程中的价值.     

The role of facial microexpression state (FMES) change in the process of conceptual conflict

This paper explores whether facial microexpression state (FMES) changes can be used to identify moments of conceptual conflict, one of the pathways to conceptual change. It is known that when the preconditions of conceptual conflicts are met and conceptual conflicts are detected in students, it is then possible for conceptual change to take place. There were 102 university and high school students who were involved in this research, and about 80% of the participants held erroneous preconceptions on the scientific topic chosen. The results showed that FMES changes were detected in the majority of the students who made erroneous predictions as they underwent conceptual conflict. Furthermore, the lack of FMES change was shown to indicate a lowered likelihood of conceptual change, while the presence of FMES change doubled the likelihood of conceptual change. The results confirm that FMES can be useful in determining learners’ awareness of conflicting concepts and their progress towards scientific understanding. Educational implications are discussed.     

Brief outlines of the parent/family reaction to childhood disability in families from 3 ethnic minority groups

The giving birth to a disabled child is the fulfilment of one of the greatest fears of expectant parents. The shock, dismay and stigmata involved are likely to be very profound. (1,2). The ways in which people deal with such catastrophe needs to be understood so that as many as possible of the disadvantages which accrue to families with disabled children can be overcome.Three families are described briefly with rather sparse detail for the sake of brevity. Likewise their biographies are vere foreshortened. Each family has been registered with the same doctor in West London who has been involved with the sustaining and understanding of the family, the support of various members of the family and the orchestration of social help as and when this was acceptable or available.     

Behavioral control by stimulus components of an imprinting object

In the first of three experiments, ducklings that had received prolonged exposure to the visibly moving imprinting object subsequently suppressed ongoing distress vocalization both during brief presentations of the moving object and during brief presentations of its initially neutral stimulus components (i.e., its auditory and static visual features). Only presentations of the moving object were followed by priming aftereffects (namely, enhancement of distress vocalization over a baseline rate). In Experiment 2, weak, but reliable, priming effects were detected after very long presentations of the auditory and static visual features. Experiment 3 found that these features strongly suppressed low, but not high, rates of distress vocalization, while the visibly moving object strongly suppressed both high and low rates. These studies suggest that initially neutral features of an imprinting object acquire the same sort of behavioral control as is exerted by the object when it is in motion, but that this control is somewhat weaker.     

Copyright and you

Educators and their attorneys must evaluate the merits of filing a federal lawsuit and the potential recovery available in litigation against the more expeditious and less costly arbitration procedure when domain name disputes are involved. Since complex intellectual property law pervades both proceedings, it is important to work with an experienced intellectual property attorney