共查询到20条相似文献，搜索用时 670 毫秒
1.
This paper presented an automatic gain control(AGC) circuit suitable for FM/cw ladar. The proposed architecture was based on two-stage variable gain amplifier(VGA) chain with a novel DC offset canceller circuit, which contained an improved Gilbert cell and a Gm-C feedback loop. To keep the VGA with a linearity in dB characteristic, an improved exponential gain control circuit was introduced. The AGC was implemented in 0.18 μm standard CMOS process. Simulation and measurement results verified that its gain ranged from-20 dB to 30 dB, and bandwidth ranged from 100 kHz to 10 MHz. Its power consumption was 19.8 mW under a voltage supply of 3.3 V. 相似文献
2.
Laser welding is an established manufacturing technology for a large variety of automotive applications due to its attractive properties such as low heat input, high precision and fast welding speed. Especially when welding high strength steels, which are dominantly used in today＇s car body construction, the low heat input by laser welding bears significant advantages with regard to the properties of the weld seam. The exploitation of the full application potential of laser welding in mass production requires an appropriate manufacturing concept and corresponding auxiliary technologies. The present paper demonstrates the integration of laser welding into the surrounding manu- facturing concepts by a modular setup with different levels of automation. This approach offers flexible solutions for individual needs thereby optimizing investment cost, labor cost and productivity. Recently available laser sources enable exceptionally high welding speed on thin gauged sheet metals but require efficient material handling con- cepts to utilize the full speed potential. Industrial concepts are presented offering efficient material handling and high process robustness for mass production welding. 相似文献
3.
Ruben Jans Ria Bollen 《美中教育评论》2008,5(7):36-40
Employees in technical firms, like garages, need more and more formations. Due to the very fast innovation in technology, lifelong learning is a real need for these labour forces. On the other hand, there are the needed formations very specialized and expensive. Another problem employers faced in these economical sectors in Western Europe is the lack of candidates. Also in secondary education schools, the wide interest for these formations is decreasing. One of the factors causes this problem is that schools don＇t have enough money for investing in new and high-tech machines. Therefore two interreg projects were submitted and approved for financing. Interreg is an initiative of the European Union meant for the permanent development of the ＂European Space＂. The third phase of interreg means enhancing the economic and social cohesion within the European Union. In this paper, we describe two successful projects, namely Autoweb and V@K, which try to help employers, employees, schools and students to keep up with the high-tech innovations with a workplace-based e-learning program. 相似文献
4.
Darra Pace Diane Schwartz 《美中教育评论》2008,5(12):20-26
The inclusion of students with disabilities at the university is a relatively new occurrence in the field of special education. Although legislation in the United States has supported the acceptance of students with disabilities at the post-secondary level, it has only provided minimal support with the emphasis on the learner rather than the curriculum. Now we are looking for multiple ways for students to access learning and demonstrate mastery. Universal Design for Learning （UDL） is currently seen as a means to reconceptionalize curriculum. This study examines the experience of four professors and their effort to use a Classroom Performance System （CPS） as part of reformatting their courses using UDL. The Center for Applied Special Technology, CAST （2001） states that the goal of Universal Design for Learning is to develop teaching methods that enable all students with diverse learning needs, including those with disabilities and cultural differences, to have equal access to classroom curriculum. This paradigm shift echoes the move in special education from a deficit model to a minority rights model put forward by Hahn （1989）, and which is the basis of inclusive educational philosophy. Together inclusion and UDL create learning environments that strive to serve all students. This research describes the implementation of clickers as part of the CPS program in college courses in a special education teacher preparation program. The case study demonstrates how technology can provide access for all learners with positive outcomes such as increased participation and application of knowledge. It also illustrates some of the difficulties in making this pedagogical paradigm shift particularly in the use of technology, and the value of overcoming the existing barriers in place. 相似文献
5.
Dennis Ping-Cheng Wang 《美中教育评论》2008,5(9):32-41
Movement activities can be used to integrate with any other curriculum in childhood education. The movements can inspire the sense of rhythmic concepts for children. This study aims at investigating how children can be motivated and inspired rhythmically by body movement through Dalcroze approach. In this research, the author revealed how physical movements can motivate children＇s potential sense of rhythm and inspire children＇s interest of musical rhythmic concepts learning. The study was conducted with 1000 primary school 6th grade students from twenty primary schools in Taipei, Taiwan. These 1000 6th grade students have the same age, same music syllabus and have equally same music training at their schools. The 1000 students were divided into two equal groups, one having different activities of body movements at school, and the other without. The different activities included tapping, swinging, clapping, turning, and stamping simple rhythms. The experiments consisted two parts which were rhythm dictation and improvisational skills. All the participants were equally given the pre-test and post-test as evidences of progress of the experiment, and the researcher then compared with the differences of the two tests of the two groups before and after the experiment to see if there were any progress in their learning of musical rhythms. The study lasted 6 months and consisted of three stages： observation, comparison, and analysis. The author observed and compared the two groups of students, analyzed the results and found out that the two groups demonstrated obvious differences in their degree of progress on learning of musical rhythms. 相似文献
6.
Christian Harteis Tina Koc Barbara Morgenthaler 《美中教育评论》2008,5(1):68-80
Intuition usually is defined as the capability to act or decide appropriately without deliberately and consciously balancing alternatives, without following a certain rule or routine, and possibly without awareness （Gigerenzer, 2007; Hogarth, 2001; Klein, 2003; Myers, 2002）. It allows action which is quick （e.g. reaction to a challenging situation） and surprising, in the sense that it is extraordinary in performance level or shape. This paper reports theories of intuition and their empirical evidence in the field of professional work. It aims at reporting the state of research on intuition, discussing the relevance of different approaches for analyzing work performance, and describing challenges for future empirical research in the domain of professional working life. 相似文献
7.
概念图在高中生物复习总结中应用的初探 总被引：1，自引：0，他引：1
陈敏 《宁德师专学报(自然科学版)》2008,20(1):92-94
高中生物复习课教学是师生双方从新的视角对所学知识进行系统梳理、深化、拓宽及灵活应用的教与学的过程．应用概念图可以有效地组织课程内容,激发学生自主构建生物学知识体系,使知识概括化、网络化,并能灵活地迁移． 相似文献
8.
阮幼丽 《宁德师专学报(自然科学版)》2008,20(2):213-215
由于基础设施的限制,农村中学学生视野较窄,但他们所处的生活环境中生物资源丰富多彩．农村中学生物教学可利用得天独厚的自然资源,促进教学,激发学生的学习兴趣,引导学生更好地学习生物,认识生物资源与人们生活的密切关系,促进学生的资源保护意识,培养高尚的情操。 相似文献
9.
YANG Xi-yao WU Yong-an 《美中教育评论》2008,5(9):50-54
The study was to investigate the vague words measurement across native and non-native English speakers and gender differences. Ninety-two students from the University of Oklahoma participated in this study by filling out an internet-based questionnaire on the vague words. The researchers put each of the thirty-two vague words in a context, or the same word put into different contexts. The participants were asked to rate the degree or the numerical value that they thought was the most appropriate in the context of the vague word. It was found that ten out of the thirty-two words had a significant difference across the native and non-native English speakers, and two of thirty-two words had a significant difference across genders. The word ＂fairly＂ showed the most significant difference interactions of language speaking by gender. 相似文献
10.
A combined numerical model of thermal field and the primary dendrite arm spacing （PDAS） was proposed to correlate the process parameters and PDAS in laser welding of Cu and A1. The solidification parameters simulated by the finite volume method with commercial software ANASYS FLUENT were applied in the PDAS model to predict the dendrite arm spacing of fusion zone. Dendrite was also examined by the metallographic method to validate the model. Results indicate that the calculated PDAS agrees with metallographic measurements reasonably, especially the Hunt model. PDAS increases apparently with increasing laser power while decreases slightly with increasing welding speed. Increasing laser power increases the secondary dendrite and increasing welding speed increases the microporosity in dendrite. 相似文献
11.
Anne Beate Reinertsen 《美中教育评论》2008,5(10):52-65
This is a writing story about trying to create just classroom assessment practices not excluding anybody and therefore an attempt to explore what an opening up to judgment, and in my view, what assessment focused on learning might mean and subsequently imply. Social justice and democracy is at stake. How to develop and improve our assessment literacy？ How to develop trustworthy and good assessment systems？ What are our tools and what methods can we use？ Given a discussion about either summative or formative assessment and preferably both, this is primarily an attempt to think about principals before turning to instruments or starting with the beginning and beyond rather than the endpoint. I argue for keeping classroom assessment as an indefinite problem, a problem not to be solved or a term not to be understood once and for all. That will hopefully foster cultural pluralism and heterogeneity around the term： learning more, learning all, all learning. Ultimately this is about the linguistic conditions for change; but as a move from language to law and as aporetic thinking and through the pivoting but liberating effects of writing; a writing both positioning and giving direction. Through language and as a right to philosophy that is. It is about creating a heteroglossia of a fresh writing inscribed in, through and with otherness; ＂another logic＂ that is. 相似文献
12.
蔡雀金 《宁德师专学报(自然科学版)》2008,20(1):77-79
新课标中明确指出评价是信息技术教学的重要组成部分,要把学生学习的过程评价与期末考试等总结性评价相结合,适度加大过程性评价在期末成绩评定中的比重．根据教学经验及新课标要求,就信息技术课程教学评价谈点滴体会． 相似文献
13.
凌美香 《宁德师专学报(自然科学版)》2007,19(1):97-100
如何充分发挥多媒体辅助教学的优势，将多媒体技术合理运用于中学生物教学，以取得最佳教学效果，是值得深入探讨的课题．在农村中学高中生物学教学过程中，对新授课、复习课以及实验课等3种课型教学进行了对照试验，认为对抽象知识教学及系统复习课运用多媒体手段效果较佳，但多媒体课件演示不能替代学生实验操作技能的训练． 相似文献
14.
Jin-Ke Yu ;Hong-Wei Li ;Qi-Jie Zhai ;Jian-Xun Fu ;Zhi-Ping Luo ;Hong-Xing Zheng 《上海大学学报(英文版)》2014,(4):353-357
In the present work, crystal structure and for- mation mechanism of the secondary phase in Heusler Ni- Mn-Sn-Co materials were investigated using X-ray dif- fraction, scanning/transmission electron microscopy and selected-area electron diffraction techniques. Experimental results showed that the secondary phase presented in both Ni44.1Mn35.1Sn10.8Co10 as-cast bulk alloy and melt-spun ribbon, possessing a face-centered cubic （fcc） NilTSn3-type structure. The secondary phase in the as-cast bulk alloy was resulted from a eutectic reaction after the formation of a primary dendritic flphase during cooling. However in the melt-spun rapidly solidified ribbon, the secondary phase was largely suppressed as nano-precipitates distributed along the grain boundaries, which was attributed to a divorced eutectic reaction. The secondary phase exhibited partial amorphous state due to high local cooling rate. 相似文献
15.
当今,大学生利用假期来到教学资源相对贫乏的偏远山区进行支教已成为大学生回报社会的途径之一。在支教逐渐被大众广泛接受的社会背景之下,提升支教项目的系统性和专业性就成为了更多支教团队追求的目标。本文将以中国地质大学(北京)学生英语专业支教实践为实例,从团队建设、前期备课、宣传工作、教学实践四个方面分析支教规范性建设的新思路,为大学生支教项目的进一步发展提出更好的实施方案。 相似文献
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17.
SU Ya-hui FENG Li-yia 《美中教育评论》2008,5(11):1-10
To promote economic and personal growth, higher education students＇ employability, ensuring their preparedness for the workforce, is emphasized. From the employer＇s perspective, judging whether a graduate is employable depends upon whether the graduate exhibits the attributes which employers value. Yet, with the growing emphasis on lifelong learning, it is important for higher education to re-consider and reframe the development and assessment of attributes of graduates in the context of lifelong learning. In this paper, these attributes will be explored in that context, and the issue of how assessment helps the development of graduate attributes is to be considered. Student engagement is proposed in this paper as the holistic, useful approach for the development of employability and lifelong learning. The holistic approach reflects the fact that what is required in a workforce is not the acquisition of knowledge, skills and dispositions per se, but the capability to make an engagement through which knowledge, skills and dispositions are connected as a whole. The lack of emphasis on students＇ engagement could lead to mistakenly selecting as important for the focus of assessment simply the acquisition of skills, knowledge or dispositions, rather than the holistic connection of these to their application in the workforce. 相似文献
18.
CHENG Zhong-yuan 《淮阴师范学院学报(哲学社会科学版)》2014,(5):699-700
The Resolution on Certain Questions of the History of Our Party since the Founding of the People＇sRepublic of China under the Direction of Deng Xiaoping
From the beginning of the Third Plenary Session of the 11 th Central Committee of the Chinese Communist Party to the end, the Central Committee of the Chinese Communist Party was considering to summary the experiences and lessons of the “ Great Cultural Revolution” and some certain questions of the history of our party since the founding of the PRC. In October 1979, Deng Xiaoping prepared to draft the resolution, and determined the general guiding ideology of establishing Mao Zedong＇s histori- cal position and upholding and developing Mao Zedong＇s thought which is the most important and fundamental key point. Deng Xiaoping maintains, after asking advices over and over again and developing extensive democracy, it is a good resolution as a whole, which really meets the original requirements and plays an important role to unify a common understanding of inner party. 相似文献
From the beginning of the Third Plenary Session of the 11 th Central Committee of the Chinese Communist Party to the end, the Central Committee of the Chinese Communist Party was considering to summary the experiences and lessons of the “ Great Cultural Revolution” and some certain questions of the history of our party since the founding of the PRC. In October 1979, Deng Xiaoping prepared to draft the resolution, and determined the general guiding ideology of establishing Mao Zedong＇s histori- cal position and upholding and developing Mao Zedong＇s thought which is the most important and fundamental key point. Deng Xiaoping maintains, after asking advices over and over again and developing extensive democracy, it is a good resolution as a whole, which really meets the original requirements and plays an important role to unify a common understanding of inner party. 相似文献
19.
龚发兴 《宁德师专学报(自然科学版)》2008,20(1):86-88
提出关注化学教学情境创设,能培养学生创新和独立解决问题的能力,诱发学生创造想象的兴趣和动机,进而培养学生的变通能力,从而有效的提升教学效率． 相似文献
20.
Time compression in supply chains is a crucial aspect involved in the integration of warehousing and transport operations in the manufacturing industries. Sup- ply chain flows could be interrupted due to many sources of delays that lead to additional time in dispatching process and reduction in customer service level. The problem considered in this paper consists of long waiting times of loading vehicles inside the plant. This work presents a simulation-based study to minimize vehicle dispatching time in a steel wire plant. Value stream map is developed to present a system perspective of processes involved in the overall supply chain. Process activity mapping is com- pleted to provide a step by step analysis of activities involved in the vehicle dispatch process. A simulation model is developed for the system and a new model is proposed to improve the delivery performance by mini- mizing vehicles＇ waiting time. 相似文献