共查询到20条相似文献，搜索用时 110 毫秒
1.
文章就城市大型排涝泵站对水泵的选型要求分析新型高压潜水泵与常规立式泵的优缺点、安全性、经济性、结合浦西排涝泵站选用高压潜水泵实践，说明此类工程中选用该泵带来的经济、环境和社会效益。 相似文献
2.
沈文锋 《泉州师范学院学报》2012,30(5):88-93
正在进行的广播的第三轮改革与国家政策的调整、社会发展和时代变迁息息相关。广播在新媒体等外界力量的作用下走向平台化,成为政治权力、商业集团、市民公众和广播自身主体等各方利益集团争夺的平台。然而不等同于公共领域的政治功能,广播平台还具有信息发布功能、交往功能、表演功能和经济功能。因此,平台化既能使广播发挥公共领域的作用,又成为广播产业经济异军突起的发生地。同时,新媒体导致的媒介融合将为广播谋求一个更大的平台。 相似文献
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李华刚 《广东教育学院学报》2007,27(5):53-55
自散焦介质中双光束斜入射耦合能发生光束偏转,通过数值模拟发现在非线性折射率不是均匀分布时光束偏转能降低抽运光功率并且偏转角度不减小,在相同的功率条件下,能产生更大的偏转.此现象对光开关的研究有一定的参考价值. 相似文献
4.
介绍了一种基于FPGA与MC8051IP核的可调窄脉冲激光泵浦系统.该系统主要作为低重复频率光信号的放大器泵浦源.系统采用MOSFET作为功率开关管驱动半导体激光器发出的光脉冲作为激光泵浦源,可驱动大功率的LD,最大驱动功率可达30W.利用高速FPGA芯片（EP2C8）和VHDL语言,设计激光泵浦源的窄脉冲数字控制电路.利用MC8051软IP核实现智能控制,系统输出脉冲周期、脉冲宽度以及脉冲幅度都可调.系统采用多种有效保护措施,性能稳定可靠. 相似文献
5.
Based on the principle of general relativity, geometrization of interaction, the interaction of the inhomogeneous isotropic
medium to light can be equated to a non-Euclidean geometry field just like the situation of gravity, i.e., light travels in the null geodesic in the non-Euclidean curved space-time, which is equivalent to the Fermat principle
for the inhomogeneous media. In this paper, the propagation of light in an inhomogeneous media is studied by means of the
effective metric theory. The modification to the classical ray equation of photons is derived from the geodesic equation of
photon by considering the spin effect of photons, which is induced via the spin-orbit coupling of photons, and the corresponding Hamiltonian of photon is proposed. Based on the spin-orbit coupling
of photon, a light splitting phenomenon emerges in the inhomogeneous media, which is the spin hall effect of photon. 相似文献
6.
Little is known about the social media use of online gamers compared with nongamers and whether the two forms of technology use manifest as the cumulative risk for relational and well-being outcomes in adolescents. Self-report data from 320 Chinese secondary school students (12–17 years) was collected for online gaming and social media use frequency, depression, satisfaction with life, and relationship quality with parents, teachers, and classmates. Once the sample was split into nongamers, light gamers, and heavy gamers, results showed that heavy gamers (cut-off at ≥2 or ≥3 h/d) were more depressed, used social media and the Internet more frequently and social media differently, and experienced more negative interactions with parents and classmates compared with nongamers. Significant differences were also found between light gamers and nongamers on certain variables. Findings indicate that heavy gamers are also using other media at heavy levels which places them in a more at-risk group for adverse well-being and relational outcomes. 相似文献
7.
提出了非线性液晶光信号放大器的原理、结构和系统,理论分析了光信号放大器的实验结果。研究表明,这种光信号放大器,由液晶光敏介质组成,这种光敏介质,能够接收已调制的信号光波和泵波,并能用于光传输系统。 相似文献
8.
推导具有一定夹角的双光束传输耦合传输方程,通过数值模拟发现了一个有趣的现象:在一强抽运光束的诱导聚焦条件下,信号光束的传输方向发生了偏转,并且偏转的角度比较大.此现象对光开关的研究有一定的参考价值. 相似文献
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池灵达 《宁德师专学报(自然科学版)》2011,23(4):389-392,403
WEB网络游戏让用户在任何地方只需打开浏览器即可进入游戏,它是将丰富互联网应用程序（RI-A）技术发挥到极致的一种具体应用.Microsoft Silverlight是.NET Framework为下一代WEB及移动设备提供的用于生成和提供跨浏览器,跨平台的媒体体验和丰富互交互式应用程序（RIA）的开发框架.研究如何以Sil-verlight技术实现WEB网络游戏. 相似文献
11.
如何争取受众是媒体竞争的核心价值。受众选择行为是媒介营销的导向和出发点。引用营销学中的顾客价值概念，从传播学的角度阐述受众选择行为的表现及其对媒介营销的影响。 相似文献
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Beryl Crooks Marie -Noëlle Lamy 《European Journal of Psychology of Education - EJPE》1995,10(2):131-144
The materials, procedures and findings of an evaluation of initial approaches to the use of audio visual media in a course teaching the French language to distance learners are reported as a case study of a formative evaluation. The study illustrates the design-research-revision stages of the formative evaluation cycle. Innovative features of the course were the pivotal role played by audiovisual (videocassette and audiocassette) media in providing resource material for teaching and learning, the use of short sequences for intensive study and the high degree of integration between the audiovisual media and the print. Key teaching design features of the draft audiovisual and print packages were identified and evaluated in terms of students’ reactions to them. Central issues of teaching design are discussed in relation to revisions made to the course materials in the light of the evaluation. 相似文献
14.
现代传媒中的性别表征研究 总被引：2，自引：0，他引：2
方建移 《湘潭师范学院学报(社会科学版)》2004,26(5):109-111
大众传播媒介是现代人主要的心理源泉。传媒对社会群体的表征受到国内外心理学家、社会学家和传媒研究人员的极大关注。通过对传媒性别表征特别是男性人物表征的考察,揭示了传媒表征发展的一些特点和减少刻板印象的意义。 相似文献
15.
Using the PISA 2015 releases in Norway and England, this article explores how PISA has been presented in the media and how the policy level has responded to the results. England will be used as an example for comparison. The article presents early media responses from the 20 most circulated daily newspapers in the two countries and discusses them in relation both to the national PISA reports in Norway and England, as well as the international report of the OECD. The media responses are further interpreted in light of previous research in both countries, with a particular focus upon Norway, where previous Ministers of Education have been interviewed about assessment policy and education reforms. 相似文献
16.
通过以不同光照条件下的 3年生曼地亚红豆杉 (Taxusmediacv.Hicksii)为材料 ,以低温半致死温度为指标 ,研究了其叶片在自然降温过程中抗寒力的变化。结果表明 :不同光照条件下的曼地亚红豆杉抗寒力发生了变化 ,其变化由大至小的顺序为 :自然光 >1层遮荫 >2层遮荫。 相似文献
17.
梁顺成 《南阳师范学院学报》2011,10(8):92-93,95
数字媒体作为一种新兴的信息技术对我们的生活影响越来越大。在数字媒体的推动下,标志设计呈现出多样化的发展趋势,针对数字媒体影响下的现代标志设计的特点进行探讨,相信通过了解这种新兴的技术一定会对我们在以后的标志设计中提出一个新的标准和要求,不断地激励和引导我们在标志设计这个领域取得更好地突破。 相似文献
18.
In light of the increased usage of instructional media for teaching and learning, the design of these media as aids to convey the content for learning can be crucial for effective learning outcomes. In this vein, the literature has given attention to how concurrent on-screen text can be designed using these media to enhance learning performance. The present study sought to examine whether utilizing concurrent on-screen summarized text (CST) could improve students’ learning performance while estimating their perception of performance when learning with educational multimedia content. Although the findings did not show a significant improvement in students’ performance on the retention test among the CST groups, students exhibited a considerable higher level of confidence toward their performance. The findings suggest that students who learned with CST educational media may have overestimated their performance. Further analysis and discussion are included. 相似文献
19.
Luke Rodesiler 《TechTrends》2017,61(3):293-300
In light of recent scholarship about teachers leveraging social media to support their continuing professional development, this article documents an investigation of school board policies governing teachers’ use of social media. Focusing on 30 traditional public school systems within a 10-county region in the Midwestern United States, the author collected social media policies and conducted an ethnographic content analysis to build an understanding of the policies that stand to guide teachers’ professionally oriented participation online. Of the 30 public school districts included in the study, 19 districts published policies specific to teachers’ use of social media. Reporting the study’s findings, the author addresses the districts’ efforts to craft policies that define social media, reiterate relevant pre-existing policies and support educational uses of social media. Implications for teachers, teacher educators and policymakers are included. 相似文献
20.
在单缝的夫琅和费衍射实验中 ,实验现象的可见度低 ,可调性也差。介绍了模拟夫琅和费衍射现象的原理及方法 ,建立了可见光波长和计算机屏幕颜色显示的相关性 ,利用光强与衍射角之间的相关性模拟光的衍射现象 ,拓展了多媒体编著工具Authorware的应用。 相似文献