用位移传感器测量固体材料的杨氏模量     

邓胜军 《湘南学院学报》2007,28(5):32-34

介绍了一种用位移传感器测量固体材料的杨氏模量的方法,是一种学生了解和掌握微小位移的非电量电测方法.  相似文献   

New multi-camera calibration algorithm based on 1D objects     

Zi-jian Zhao  Yun-cai Liu 《浙江大学学报(A卷英文版)》2008,9(6):799-806

A new calibration algorithm for multi-camera systems using 1D calibration objects is proposed. The algorithm integrates the rank-4 factorization with Zhang （2004）＇s method. The intrinsic parameters as well as the extrinsic parameters are recovered by capturing with cameras the 1D object＇s rotations around a fixed point. The algorithm is based on factorization of the scaled measurement matrix, the projective depth of which is estimated in an analytical equation instead ofa recursive form. For more than three points on a 1D object, the approach of our algorithm is to extend the scaled measurement matrix. The obtained parameters are finally refined through the maximum likelihood inference. Simulations and experiments with real images verify that the proposed technique achieves a good trade-off between the intrinsic and extrinsic camera parameters.  相似文献   

The inattentive on-screen reading: Reading medium affects attention and reading comprehension under time pressure     

《Learning and Instruction》2021

This study explored the influence of reading media and reading time-frame on readers' on-task attention, metacognitive calibration, and reading comprehension. One hundred and forty undergraduates were allocated to one of four experimental conditions varying on the reading medium (in print vs. on screen) and on the reading time-frame (free vs. pressured time). Readers' mindwandering while reading, prediction of performance on a comprehension test, and their text comprehension were measured. In-print readers, but not on-screen readers, mindwandered less on the pressured than in the free time condition, indicating higher task adaptation in print. Accordingly, on-screen readers in the pressured condition comprehended less than the other three groups. Mindwandering and text comprehension were similar under free reading time regardless of medium. Lastly, there were no differences in readers’ metacognitive calibration. The results support the hypothesis of shallow information processing when reading on screen under time constraints.  相似文献   

基于虚拟仪器的热电偶温度传感器的标定   总被引：3，自引：0，他引：3  

彭长青  王寒栋  李鸣  蔡志敏 《深圳职业技术学院学报》2008,7(1):7-11

为了使热电偶温度传感器在实验过程中所测的温度可靠、实用,就必须对热电偶温度传感器进行标定。本丈主要介绍一种利用虚拟仪器技术结合恒温水浴装置来进行热电偶温度传感器进行标定的实验方法,主要从标定系统的总体结构、硬件设计、软件设计、热电偶温度传感器标定实验的数据分析及热电偶温度传感器的校正等方面进行了讨论。实验结果显示这种标定方法可靠实用。  相似文献   

水流量实验装置计算机控制系统   总被引：1，自引：2，他引：1  

李巧真  李刚  罗翼 《实验技术与管理》2006,23(8):72-75

该设计是开发出水流量标准装置的计算机控制系统,涵盖了流体力学、检测技术、误差理论、电工电子以及Visual basic 6.0语言等方面的知识,设计内容包括：实验装置精确度检定,用标准表法或称重法标定涡轮流量计和浮子流量计,实验数据的保存和查询,报表的打印输出.  相似文献   

应用于低中频Zigbee收发机的5-GHz恒定带宽频率综合器（英文）     

姜亚伟  李智群  舒海涌  侯凝冰 《东南大学学报》2010,26(1):6-10

设计并实现了一个应用于ZigBee收发机的全集成整数N频率综合器.频率综合器中采用了稳定环路带宽技术,使频率综合器的环路带宽在压控振荡器（VCO）的整个输出频率范围内恒定不变,从而维持了频率综合器的相位噪声最优值与环路稳定性.频率综合器的同相与正交信号（IQ）由VCO输出端的除2分频器产生.该频率综合器采用0.18μm RF CMOS工艺技术制造,芯片面积约1.7mm2.频率综合器采用在晶圆测试的方式进行了测试.在1.8V电源电压下,频率综合器不包括输出缓冲所消耗的总功率为28.8mW.频率综合器在2.405GHz载波1及3MHz频偏处测得相位噪声分别为-110和-122dBc/Hz.频率综合器在2MHz频偏处测得的参考杂散为-48.2dBc.测得的建立时间约为160μs.  相似文献   

对称式微波功率传感器的幅度调制测量（英文）     

王德波  廖小平  田涛 《东南大学学报》2010,26(1):68-72

为了减小失配造成的测试误差,在测量调制信号的微波功率时提出了一种直流校正方法.在传感器左端输入微波功率,右端输入直流功率,微波功率存在的寄生损耗和电磁耦合造成了失配误差,而直流功率不存在失配误差,所以通过右端输入的直流功率可以校正左端微波功率的失配误差.测试了在不同调制率和调制深度的校正因子.测试结果表明,载波频率是造成幅度调制测试误差的主要因素,校正后载波频率和调制率对输出电压的影响很小,频率响应在20GHz范围内变得相对平滑,而且灵敏度平均提高了大约0.12mV/dBm.因此,该直流校正方法对于终端式微波功率传感器具有一定的参考意义.  相似文献