手指静脉识别技术研究发展现状综述

指纹识别技术在安检、门禁、考试等方面得到了很好应用,但指纹存在于皮肤表面,有一些不可避免的缺点,会影响识别效果.而手指静脉识别技术能完全克服指纹识别的缺点,使身份认证更加方便快捷.对静脉识别技术的特点以及国内外的发展现状进行了介绍.     

A novel non-iterative shape method for estimating the decay time constant of the finger photoplethysmographic pulse

The photoplethysmogram (PPG) of a pulse wave, similar in appearance to the arterial blood pressure (ABP) waveform, contains rich information about the cardiovascular system. The decay time constant RC, equal to the product of peripheral resistance R and total arterial compliance C, is a meaningful cardiovascular model parameter in vascular assessment. Using or ameliorating the existing ABP methods does not achieve a satisfactory estimation of RC from the PPG volume pulse (VRC). Thus, a novel non-iterative shape method (NSM) of evaluating VRC is introduced in this paper. The mathematic expression between a novel, readily available morphological parameter called the area difference ratio (ADR) and VRC was established. As it was difficult to calculate VRC from the complicated expression analytically, we recommend estimating it using a piecewise linear interpolation criterion. Also, since the effect of the PPG magnitude is eliminated in the calculation of ADR, precaliberation or normalization is dispensable in the NSM. Results of human experiments indicated that the NSM was computationally efficient, and the simulation experiments confirmed that the NSM was theoretically available for ABP.     

美国鼓励说中国普通话

美国教育部部长玛格丽特·斯佩林斯称，随着中国的崛起，流利说中国普通话对于美国学生来说已变得“极其重要”。[第一段]     

Treating oil wastewater with pulse electro-coagulation flotation technology

Pulse electro-coagulation flotation was used to treat oil wastewater of high oil content. Different operational conditions were examined, including current density, reactive time, electrode distance, pH and pole switching time. Orthogonal tests were carried out to identify the optimal operational conditions for this technique. Considering the treatment cost and efficiency together the optimal operational conditions were an electrode distance of 3.3 cm, pH of 4, current density of 49.38 mA/cm2, reaction time of 15 min and pole switching time of 10 s. The removal efficiency of oil wastewater under normal conditions reached up to 96.21%. The influences of different factors on removal efficiency were in the following decreasing sequence： pH〉 current density 〉 pole switching time 〉 reactive time 〉 board distance.     

美国重视幼儿教育科研

2000年，美国教育部公布了《教育研究国家重点》，这是国家教育研究政策委员会与教育研究改进局根据国会的要求，经过三年调查研究后制订的。其目的在于适应 21世纪的需要，大幅度地提高教育水平，迎接新的挑战与机遇。文件序言中谈到：美国人把最热切的希望寄托于教育，教育在美国起到无可比拟的重要作用；长时间里，美国通过教育来解决社会、政治、经济等方面的问题；当苏联发射人造地球卫星时，美国人的反应是改革学校教育，国会通过了具有里程碑意义的教育立法；今天，世界范围的政治与技术的变化带来另一次信心危机与机遇，面对各种挑…     

Commercialising comparison: Pearson puts the TLC in soft capitalism

Abstract

This paper provides a critical policy analysis of The Learning Curve (TLC) (2012), an initiative developed by the multinational edu-business, Pearson, in conjunction with the Economist Intelligence Unit. TLC exemplifies the commercialising of comparison and the efforts of edu-businesses to strategically position themselves in education policy processes globally. In analysing TLC, our account seeks to proffer a critical analysis of this emerging policy genre, and the way it functions as part of the new ‘soft capitalism’. We analyse TLC in relation to Pearson’s new business strategy, which emphasises corporate social responsibility and accountability to consumers for the efficacy of its products and services. We argue that Pearson is now generating and appropriating various data to legitimise its products and services according to a ‘neo-social’ mode of accountability. Network ethnography is employed to document the global networks of both people and data associated with TLC and we reflect on the emergence of Pearson as a potential education policy actor.     

基于空间电压矢量脉宽调制技术的感应电机变频调速系统研究

由于电压空间矢量脉宽调制(SVPWM)技术具有物理意义直观、数学模型简单、便于微处理器实时控制等优点,因此在电机控制中得到了广泛的应用。介绍了一种以数字信号处理器TMS320F2812为核心的感应电动机变频调速系统,采用SVPWM技术实现了对感应电机的变频调速控制。实验结果表明,采用SVPWM技术的感应电动机变频调速系统具有动态特性好、转矩脉动小、噪声低和电压利用率高等特点。     

基于传感器的手指运动姿态监测

针对动态测量手指关节角度的需要,设计了基于传感器的手指运动姿态监测方法。从可穿戴式设备的角度出发,在分析了PVDF压电薄膜传感器、电阻应变片和三轴加速度计ADXL330工作原理的基础上,设计了动态角度测量实验和3组监测实验;传感器固定在手套的对应关节的位置处。对比3组实验,分析实验数据,得到结论:PVDF压电薄膜传感器动态响应快,适合高频激励下手指运动姿态的监测;电阻应变片在高频激励下的响应有一定的延迟,这种响应迟后对动态应变测量会产生误差,其比较适合低频激励下手指运动姿态的监测;加速度计ADXL330在低频激励下能较好地实现对手指运动姿态的监测,其工作的稳定性和可靠性良好。     

为爱情点上一盏灯

Valentine's Day may only be a few days away,but there's no reason to panic.Just because youhaven't been planning since New Year's,doesn't mean your beloved has to be disappointed.Here are some ideas to appease even the mostromance-starved partners.     

Involve your preschool with the community

A vast resource of educational experiences waits within your school's immediate community. Teachers should be more eager to involve themselves and their school in community relations, which can increase their effectiveness and also act as good publicity for the school itself. The community needs to know what good education for its young children is, and how it can be a part of it. It can recognize preschools as performing a vital community service and be willing to come together to exchange experiences. Children are not only our future, but they are part of our community's present.     

浩瀚星辰,尽在指尖

<正>霍金走了,带走了关于宇宙与时间的未解之谜。广袤的宇宙里,黑洞正在吞噬着一切,无数的小行星正在飞向地球,还有那梦幻的星云正幻化出多姿多彩的形态……也许霍金并没有死,他只是摆脱了那个禁锢在轮椅里的躯壳,飞向了他一直向往的浩瀚星辰。     

My tongue on your theory: the bittersweet reminder of every-thing unnameable

ABSTRACT

Across research in UK Higher Education, the most immanent demands for quality have taken the shape of the Research Assessment Exercise and the Research Excellence Framework (REF). The theorist, Martin, is cautious of the relationship academics have engendered with the process of the REF, asking are we actually creating a Frankenstein monster, becoming complicit in generating quality thresholds and standards that will become our own tormentors? I am taken by the idea of the monster when pursuing alternative discourses of childhood in educational research – fear of its potential to torment seduces me with the promise of dis-order, de-formity, chaos and mutation. The aim of this paper is to resist a fixed, knowable form of ‘quality’ (in) research, moving between the idea of ‘monster’ and the formlessness of ‘monstrosity’ to oppose the epistemological, ontological and ethical paradigms of reason.     

"无需举手,自由发言"

“这个问题谁能回答?”教师的话音刚落,一些或许多学生便举起手,然后教师点名,学生回答,这是中小学课堂教学中的一个场景,而在上海外国语大学附属大境中学,这已是上个世纪的事了。现在老师们仍然这样问:“这个问题谁能回答?”但学生已不必再由教师“钦点”,常常是教师一发问,便有十多个学生同时站起来抢着发言。而且现在教师也不用为评判学生回答的“对”或“错”而大费周章,学生们大多会在相互讨论、争论中得出比较正确的答案。一些原先沉默寡言的学生也会受到气氛的感染,情不自禁地站起来发表意见。这就是大境中学实行“无需举手,自由发言”后的课堂教学情景,学生们将此举称为“思维的解放”。