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1.
本文研究了一种硅高频高跨导JFET的设计和制造技术，测量结果表明，所研制的器件性能基本达。到了国际上先进公司同类产品的指标参数。 相似文献
2.
《信阳师范学院学报(哲学社会科学版)》2017,(3):132-135
美国当代著名作家唐·德里罗的小说《白噪音》艺术地再现了后现代美国人的生存环境和生存状态。美国消费社会建构的三个关键领域——媒介影像、消费行为和大众文化,成为美国后现代社会的景观。《白噪音》展示了后现代美国社会的两大消费行为——看电视和购物,同时,揭示了美国大众文化甚至学术研究也趋向商业化。这些异化消费使得人们丧失了主体性,陷入了精神空虚、焦虑、孤独与异化,并导致垃圾激增、环境污染和生态灾难。 相似文献
3.
Ching Yee Choi 《International Journal of Disability, Development & Education》2005,52(4):345-360
Many researchers have stressed that the acoustic environment is crucial to the speech perception, academic performance, attention, and participation of students in classrooms. Classrooms in highly urbanised locations are especially vulnerable to noise, a major influence on the acoustic environment. The purpose of this investigation was to determine noise levels in one such urban environment, Hong Kong. The ambient noise level, and its relationship to the speech intensity levels of both teachers and students was surveyed in 47 primary school classrooms. Moreover, the presence of acoustical treatments for noise reduction and the use of classroom amplification systems were documented for each classroom. The survey found that the mean occupied noise level was 60.74 dB (A); the mean unamplified and amplified speech‐to‐noise ratios of teachers were 13.53 dB and 18.45 dB, respectively; while the mean unamplified speech‐to‐noise ratio for students was 4.13 dB. Most of the classrooms exhibited insufficient acoustical treatments to provide significant noise reduction. The listening environment in many Hong Kong primary schools was not favourable for optimal classroom learning. Recommendations for improving the acoustical environment in classrooms in highly urbanised locations such as Hong Kong are discussed. 相似文献
4.
The term noise is used to describe fluctuations about the mean deterministic stationary value of a physical quantity. It is
now being increasingly realised that noise is an important ingredient to bring order in dynamical processes. Though it appears
counterintuitive, noise seems to help in directing transport processes in biological systems at the molecular level. In Part
2 of the article, we discuss some more examples of noise assisted directed motion. 相似文献
5.
We use prices realized for Picasso prints at auctions worldwide, as well as the 100 prints that comprise his Vollard Suite,
to test the law of one price: the proposition that identical art objects sold contemporaneously should command the same price
regardless of the auction house or geographic region where the sale takes place. Picasso is the most prolific printmaker of
the twentieth century and, from 1977 to 2004, his prints appreciated in price significantly faster than the prints of modern
masters as a whole. We find that Picasso prints sold in the United States command higher prices than in Europe. However, prices
realized at Sotheby’s in New York are no longer higher than at Christie’s in New York, nor at Kornfeld than at other auction houses. We find evidence of “irrational exuberance”
in the transitory nature of the extraordinary prices realized for the Picasso prints included in the 1997 sale of the collection
of Victor and Sally Ganz at Christie’s in New York. More generally, we find substantial noise in auction outcomes, a result
well known to savvy auction goers.
相似文献
| Pauline M. Shum (Corresponding author)Email: |
6.
随机共振能将噪声的部分能量通过非线性系统作用转为信号的能量,从而提高输出信号的信噪比,这为解决从强噪声背景中检测提取有用弱信号问题提供了一种全新的思路和方法。将随机共振机制应用于图像复原,可以提高图像复原效果,特别是在处理被强噪声污染的图像信号时。 相似文献
7.
液压齿轮油泵噪声的诊断与控制 总被引：3，自引：0，他引：3
陈文辉 《安徽职业技术学院学报》2005,4(1):21-23
噪声是齿轮油泵常见的故障之一,解决这一故障有利于齿轮油泵正常工作。文章分析了齿轮油泵产生噪声的原因,并根据产生噪声的不同机理找出了有效的解决措施。 相似文献
8.
基于瞬时功率理论的谐波检测方法由于锁相环和低通滤波器的存在,给检测环节带来了一定的延时,使得谐波电流的检测存在一定的误差。本文通过增加预测补偿角来消除该环节带来的延迟时间,从而能够更加准确、有效地得到谐波补偿指令信号。最后利用MATLAB搭建了仿真模型,仿真结果表明了该方法的有效性。 相似文献
9.
病毒检测与防御是计算机安全中的一个很重要的研究课题。目前,计算机病毒的花样不断地翻新,并大量使用了多重加密壳、变形、多态,传统的恶意代码查杀技术很难进行正确的查杀,这是因为病毒代码被感染后,为了躲避检测会对自己本身的代码修改替换。即使是针对未知的恶意代码,如果只是运用简单的模式匹配算法,也会被恶意代码欺骗而逃避检测。本文介绍了一种能够检测以上未知恶意代码的方法。具体来说,首先将病毒的二进制代码进行反汇编,在汇编代码层次上进行检出以及通过汇编层次检测出的模式学习和根据学习结果的分类判定来进行检测。 相似文献
10.
现代彩色静电照相数字印刷出现以不同半色调算法复制彩色图像的趋势。影响最终印刷图像噪声表现的因素包括数字半色调算法、纸张类型以及墨粉颗粒形状和尺寸的非均匀性等,其中半色调算法决定网点结构,成为本文讨论的重点。 相似文献