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排序方式: 共有191条查询结果,搜索用时 31 毫秒
1.
光催化剂利用太阳能可以充分降解生活及工业废水中的有机污染物。与其他传统方法相比,在催化效率、低毒、可回收性等性能上,有着无可比拟的优越性。半导体材料在吸收能量大于或等于其禁带宽度的光子后产生电子及空穴,经过一系列的反应,转化为具有强氧化能力的羟基自由基,来降解染料等工业废品。由于晶体结构缺陷及自身结构等特征,光生电子与空穴极易发生复合,使得产生的活性羟基自由基数量变少,减弱光催化能力。异质结构的存在,加速了电子与空穴的分离,延长电子空穴的存活寿命,对提高光催化活性有着重要的影响。  相似文献   
2.
利用语音信号的短时平稳特性,提出了一种二阶特征窗语音盲分离方法。该方法采用新的联合差分相关矩阵白化算法去除有色噪声影响;用长度等于语音信号基音周期的等距特征窗连续分割预白化观测数据,在每个加窗的数据帧计算不同的时滞协方差矩阵。利用联合近似对角化时滞协方差矩阵集合得到旋转参数,最终达到语音信号的盲分离。该方法消除了有色噪声的影响,只需用到二阶信息就能很好地分离语音信号。仿真实验验证了该方法的有效性。  相似文献   
3.
模拟人工测量过程,设计了一种适用于气体测微传感器自动测量孔径的柔顺机构.该机构也适用于孔径分选以及小型轴类零件的自动装配等作业过程.  相似文献   
4.
《金融会计》课程的教学与近几年来金融业迅猛发展的趋势不相适应 ,在认识上、教学内容上和教学手段等方面存在种种误区  相似文献   
5.
椭圆曲线数字签名实际上是基于乘法群的离散对数的数字签名在椭圆曲线上的模拟。本文讨论了部分盲签名的概念,并提出了两个基于椭圆曲线的部分盲签名方案,即单密钥部分盲签名方案和双密钥部分盲签名方案。该方案主要用于提高离线电子系统的效率和需要较短密钥的应用产品。  相似文献   
6.
Vision plays a privileged role in social interaction and the construction of intersubjective reality. Given that one of sociology's tasks is to problematize the taken for granted, research that examines rarely foregrounded non‐visual modes of sensory perception is a powerful resource. This article draws on twenty‐seven interviews that explore blind people's perceptions of male and female bodies. I highlight several distinctive features of non‐visual sex attribution (salience, speed, and diachronicity), and argue that conceptions of sex as “self‐evident” primarily reflect visual perception. These findings suggest the need to explore the sociology of perception as a new approach to the sociology of the body, and more broadly highlight the role of sensory perception in the social construction of reality.  相似文献   
7.
A survey of state mental health agencies found that a majority have no specific policy or procedure regarding how to provide mental health services to persons who are deaf or who are deaf-blind. Agency representatives report that staff lack knowledge of how to provide mental health services to persons who are deaf-blind and the agencies lack qualified interpreters. They recommend training for social workers and counselors to address best practices in working with people who are deaf-blind concerning communication methods and strategies, physical interaction, cultural issues, everyday life, sensory deprivation, ethics, use of an interpreter, and other general issues.  相似文献   
8.
This paper shows how a public media can effectively utilize its social capital, and integrate with different resources from the related non-profit organizations and corporations in public relations perspective. A case study of a high-popularity Taiwanese public traffic radio: Police Broadcasting Service (PBS) is conducted. The finding shows that the public radio can cost-effectively deliver health communication with the principle of social marketing.  相似文献   
9.
What does it mean for a private enterprise in China to be embedded in a family? Our purpose here is twofold: (1) use social network analysis to describe what it means for a firm to be embedded in a family, (2) reveal from the application a new kind of firm, not family, yet akin to family. Armed with data on a large probability sample of private enterprises — a third of which meet ownership and employment criteria of being family businesses — we uncover a category of “hybrid family firms” that look modern in the style of firms that exclude family, but operate socially in ways similar to family firms. Our conclusion from summary statistics on the sample is that there are no differences in average performance level or network advantage for the three categories of businesses: family firms, hybrid family firms, and family-excluded firms. The fact that CEOs of family firms and hybrid family firms more often turn to family as key business contacts is a fact about network composition that raises no question about network mechanisms. Whether the CEO turns to more or fewer family contacts, government help is more likely with stronger political connections, and business success and survival are more likely with a large, open network. That said, the look-modern, act-traditional hybrid family firms stand alone in prospering with a CEO embedded in a closed business network. Recognition of hybrid family firms adds to the literature’s illustrations of social network analysis used to distinguish types of businesses and business people, and extends the population of organizations within which governance and strategy are likely to be better understood when viewed through a family logic.  相似文献   
10.
雷达工作于脉冲工作状态时不可避免的会出现盲速现象。可通过参差重频的方法减少盲速带来的影响。在推导频率响应的基础上,该文采用最优化设计的方法进行参差周期的设计,详细考虑并推导得到了最优化搜索中几个重要参数,给出了其解析表达式。仿真结果和频率响应图表明,该方法得到的参差周期能将慢速扩大到原来盲速的数倍以上,有效地减少了盲速的影响。  相似文献   
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