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题目设a、b、n＞0,0＜x＜π/2.求函数y＝a/cosnx b/sinnx的最小值. 对此问题,文[1]、[2]、[3]都得到了很好的解决,但解决的办法都比较繁.在此,笔者采用构造"数字式"解决此问题. 相似文献
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李孜 《洛阳工业高等专科学校学报》1997,(3)
本文通过一个微机维修实例,说明了微机CPU参数设置不正确,会引起一些现象与原因貌似分离的故障。对组装兼容机提出了较严格的要求,同时对维修类似故障提出了新思路。 相似文献
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In this study a new dynamic model of a rotor system is established based on the Hamilton principle and the finite element method (FEM). We analyze the dynamic behavior of the rotor system with the coupled effects of the nonlinear oil film force, the nonlinear seal force, and the mass eccentricity of the disk. The equations of the motion are solved effectively using the fourth order Runge-Kutta method in MATLAB. The dynamic behavior of the system is illustrated by bifurcation diagrams, largest Lyapunov exponents, phase trajectory diagrams, and Poincaré maps. The numerical results show that the rotational speed of the rotor, the pressure drop in the seal, the seal length, the seal clearance, and the mass eccentricity of the disk are the key parameters that significantly affect the dynamic characteristics of the rotor system. The motion of the rotor system exhibits complex types of periodic, quasi-periodic, double-periodic, multi-periodic, and chaotic vibrations. This analysis can be used to guide the design of seal parameters and to diagnose the vibration of rotor/bearing/seal systems. 相似文献
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《Journal of Further & Higher Education》2012,36(3):225-238
This study explores the dimensions of the work/life/study balance and its influence on student participation in higher education, through a case study of the experience of higher education students, studying both full time and part time, in a Scottish further education college. The experience of the students and the work/life/study challenges that they face stand in marked contrast to the traditional conception of university students, on which higher education policy is usually based. The majority of the students in this case study combined study with work and/or family commitments and the normal ‘working’ week was of 59–71 hours. Full time and part time students experienced different but equivalent demands on their time and were equally at risk of overload. Over half of the students achieved a good or manageable work/life/study balance, whilst some experienced stress caused by conflicting priorities. The students' success in balancing study with work and family life was influenced by their coping strategies and by the nature and quality of the support they received from families and employers. It is recommended that there is scope for the further development of an institutional culture and ethos that is compatible with the reality of the students' busy lives. A case is made for the equalization of financial support for full time students and part time students. 相似文献
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Daniel T. Barney 《The International Journal of Art & Design Education》2019,38(3):618-626
A/r/tography is often considered to be an arts and education practice‐based research methodology, but this author explores a/r/tography as a pedagogical strategy that has informed the author's artistic practice and pedagogical experiments. The author tracks his own journey of entering into an a/r/trographic world and where that entering has positioned him as an artist and educator and then moves on to speculate a possible arts education as his a/r/tography contorts into conceptual doings. Walking is used as a concept, as a process or method to generate more concepts, and as an art form with pedagogical potential within several undergraduate and one graduate course at the author's university. The author also investigates alongside or in concert with the courses he gives. The author equates artistic concepts, like walking, with theoretical and philosophical arguments, assertions and propositions. Artistic processes are equated with methods and methodological concerns, even though these systems of inquiry and knowing may be idiosyncratic in artistic inquiry. And finally, an art form can be understood in research terms as a type of research product or creation, that can be an event, performance, or a continuation of these as write ups or presentations, that are shared with the general or a particular public. 相似文献
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Brian Hendley 《Journal of Philosophy of Education》1978,12(1):141-148
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On the assumption that the successful implementation of any inclusive policy is largely dependent on educators being positive about it, a great deal of research has sought to examine teachers' attitudes towards the integration and, more recently, the inclusion of children with special educational needs in the mainstream school. This paper reviews this large body of research and, in so doing, explores a host of factors that might impact upon teacher acceptance of the inclusion principle. The analyses showed evidence of positive attitudes, but no evidence of acceptance of a total inclusion or ‘zero reject’ approach to special educational provision. Teachers' attitudes were found to be strongly influenced by the nature and severity of the disabling condition presented to them (child-related variables) and less by teacher-related variables. Further, educational environment-related variables, such as the availability of physical and human support, were consistently found to be associated with attitudes to inclusion. After a brief discussion of critical methodological issues germane to the research findings, the paper provides directions for future research based on alternative methodologies. 相似文献
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Sara Kim Douglas M. Brock Adam Orkand & Michael L. Astion 《British journal of educational technology : journal of the Council for Educational Technology》2001,32(5):595-605
To examine interface issues in an educational software program, we recruited twenty-two users in health sciences departments for a usability study. Using the GramStain-Tutor™ (GST) CD-ROM, these users performed tasks in navigating the program and using various interactive features. Their actions and comments were recorded with a digital video recorder and an audio recorder. The main results of our study are: (a) the majority of the users did not use the multiple navigational options available in the program; (b) navigational patterns differed based on the training background and content knowledge of the users; (c) several visual cues critical to program use were not discovered by the majority of the users; and (d) icons representing specific functions were not intuitive from users' perspectives. We demonstrated how a usability study of a relatively small number of users can identify specific problems in interface design. We recommend these interface problems be addressed before conducting educational studies that examine how educational software programs affect student learning. 相似文献
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Donna Kalmbach Phillips Robert Ch. Nava 《Discourse: Studies in the Cultural Politics of Education》2011,32(1):71-83
This inquiry explores who is the ‘good teacher of color’. Through Michel Foucault's notion of biopower and disciplinary power, the analysis attempts to problematize the subject-position of ‘teacher of color’ by exploring how a Latino intern and a Latina intern negotiated their subjectivity in a large diverse school district. Participants' construction of subjectivity was found to be located within the nexus of the school district, the university, and the Latino counter-discourse through which biopower and disciplinary power operated. 相似文献
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Christina Bratt Paulston 《International Review of Education/Internationale Zeitschrift für Erziehungswissenschaft/Revue internationale l'éducation》1978,24(3):309-328
Group bilingualism is typically the result of ethnic groups in contact and competition, where one group becomes bilingual, a concomitant condition of the degree of integration. The nature of the relationship is influenced by 1) the origin of the contact situation 2) the degree of enclosure and 3) the degree of control by dominant groups. Migrant groups tend to shift languages after some generations of bilingualism; colonized and annexed groups tend to shift languages at a much slower rate. Bilingual education may have the goal of language maintenance or induced language shift. The paper closes with a discussion of the development of bilingual education from this perspective. 相似文献
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利用N2物理吸附、XRD和空气热重对Cu-ZnO/Al2O3甘油加氢催化剂在制备过程中物相结构的变化进行了系统的研究.研究结果表明,干燥后催化剂主要由Cu2Zn4Al2（OH）16CO3 4H2O和Cu2（OH）2CO3物相组成,经过600℃焙烧4 h后,催化剂在沉淀过程中生成的Cu2Zn4Al2（OH）16CO3 4H2O和Cu2（OH）2CO3全部分解为CuO.在500℃催化剂具有最大的比表面积（79 m^2/g）和孔容（0.36 cm^3/g）. 相似文献