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971.
介绍了一种基于SoPC的双频激光回馈位移测量系统的实现方法。该系统利用双频激光回馈理论和数字细分电路,对两路正交的光回馈信号采用五细分和四细分电路相结合进行细分处理,解决了单偏振光测量位移分辨率不高的问题。实验证明了本系统的可行性,精度达到了0.791 nm,是一种应用很好的位移测量系统。 相似文献
972.
973.
974.
Recently, there has been high demand on miniaturizations of bio-instruments and wide range gas flux measurement in the field of chemistry and mechanics. This paper presents the design, fabrication, and characterization of a silicon-glass-based thermal distribution gas flow meter (20 mm × 10 mm × 1.6 mm) with a wide detection range. To facilitate the fabrication and maintain the stability of the sensor, a platinum (Pt) thin film was adopted as the heater and thermometers. Both the thermal property and temperature sensitivity of Pt thin film were characterized. SiO2 passivation layers were deposited on top of the Pt film to prevent thermal and electrical shift of sensitive elements. Three pairs of thermometers were constructed beside the heater. Sensitivity and gas flux range of the gas flow meter can be increased by alternate use of these three sensor pairs. We also introduced a specific hardware control circuit system for real-time gas flux monitoring through the connection with a computer interface. The proposed gas flow sensor device was capable of measuring gas flux within the range of 0.8-2800 ml/min, thus demonstrating the potential for a wide range of applications. 相似文献
975.
《Ergonomics》2012,55(5):663-670
The aim of this study was to compare estimation of energy expenditure (EE) in working environments, either from accelerometry or from an individual oxygen consumption/heart rate ([Vdot]O2/HR) regression curve. The study participants were 46 volunteer workers aged 27±6 years old. A significant correlation between EE predicted by the [Vdot]O2/HR curve and the accelerometer was observed (r=0.78, p <0.01). However, more disparities were observed between the two methods when the mean job intensity was not within 16% and 23% higher than resting HR. The accelerometer overestimated by a mean of 34.4% the prediction by [Vdot]O2/HR regression if the intensity of the task was lower than a total of 1000 kcal/shift and underestimated the prediction by a mean of –24.9% if EE estimation of the work shift was higher than a total of 1500 kcal/shift. Despite a high correlation between both methods in the whole group, EE evaluated by accelerometry does not correspond to EE predicted by the [Vdot]O2/HR regression curves when evaluated individually. 相似文献
976.
《Behaviour & Information Technology》2012,31(12):1305-1311
The present paper addresses a need for a brief assessment instrument to measure perceived visual aesthetics of websites. A short version of the Visual Aesthetics of Websites inventory (VisAWI; Moshagen and Thielsch 2010) called VisAWI-S was developed and evaluated in three studies comprising 1673 participants in total. The results indicate that the VisAWI-S is a reliable measure that captures a single dimension of perceived visual aesthetics and provides a good approximation to the full-length version. Convergent validity was established by a strong relationship to overall appeal. Evidence for divergent validity was obtained by weaker correlations to perceived usability, pragmatic quality and quality of content as well as by absence of a significant correlation to participants’ mood. In addition to this, the VisAWI-S was found to be substantially related to the intention to revisit a website. Overall, the results indicate that the VisAWI-S may gainfully be employed to measure perceived visual aesthetics of websites when assessment times must be kept to a minimum. 相似文献
977.
针对传统双频三维轮廓测量方法存在分辨率低、数据处理时间长等问题,提出基于空域均值的双频三维轮廓测量方法。该方法通过空域均值图像对采集到的包含物体深度信息的双频结构光图像进行处理,得到物体表面的真实深度信息,提高测量效率和测量精度。通过对物体模型的测量,证明由该方法构成的系统输入、输出满足线性关系,并且可以实现高效、高分辨率的三维物体轮廓测量。 相似文献
978.
在智能粮库计量系统中,粮面三维图形的还原与粮食质量的计算是粮库监管的一项重要内容.本系统采取将超声波传感器等设备非均匀地布置于粮仓内,用以获取粮面的部分信息,在合适的数学模型下还原出粮面的三维图形,并计算出粮食的体积和粮库的储粮质量,不仅能大幅度降低系统成本,而且具有安全、可靠、直观、高效等优点. 相似文献
979.
980.
混沌信号与谐波信号的分离问题是混沌信号处理中的重点问题,时频分析理论的日趋成熟为该问题带来了新的解决方案。针对不同噪声情况下混沌背景下谐波信号的提取进行分析,将小波变换与EMD方法进行比较,经仿真实验总结出一种新的谐波信号提取的融合算法,仿真实验验证了该算法的有效性。 相似文献