基于LabVIEW的大学物理虚拟实验设计——以“单臂电桥法测电阻”为例

单臂电桥法测电阻实验是理工科大学物理基础实验之一,在实验教学中占有重要的地位。基于虚拟仪器开发平台（LabVIEW）,制作了单臂电桥法测电阻实验并投入实验教学,取得良好的实验效果。     

双臂电桥测量接触电阻的研究

介绍了双臂电桥测量低值电阻的理论,通过改变QJ44型双臂电桥连接法测量金属棒的电阻率及引线电阻和接线头的接触电阻.实验表明:电阻率的测量结果与引线电阻和接触电阻无关,从实验上说明了双臂电桥要四端接线的必要性.     

用单臂电桥测低电阻

1 引言 传统上测量低电阻要用直流双臂电桥.但在一定条件下单臂电桥也能精确测量低阻.本文介绍两种用自组单臂电桥测量低阻的方法.所用电路结构简单,测量方法和公式简单,且从理论和实验两方面证明,只要标准低阻和待测低阻两相邻电压接头间的电阻(称为跨桥电阻)适当小,所用方法的测量结果就能达到最佳测量精度,即跨桥电阻为零时自组单桥的测量精度.     

基于LabVIEW的大学物理实验教学系统

基于LabVIEW提供的多种显示插件和输入插件相互组合,设计了大学物理实验的虚拟教学系统.以冲击电流计、单臂电桥和示波器实验为例,介绍了虚拟教学系统的设计方法.     

电桥法测金属电阻率的实验数据处理分析

用双臂电桥法测量了金属铜电阻随长度的变化,应用matlab软件处理实验数据得出了金属铜的电阻率,且给出了相对不确定度,为更好地开发大学物理实验数据处理系统打下基础。     

电桥法测金属电阻率的实验数据处理分析简

用双臂电桥法测量了金属铜电阻随长度的变化,应用matlab软件处理实验数据得出了金属铜的电阻率,且给出了相对不确定度,为更好地开发大学物理实验数据处理系统打下基础。     

基于“单臂电桥测电阻”的一个设计性实验——单臂电桥测检流计内阻

结合＂单臂电桥测电阻＂这个实验的特点提出了一个设计性实验,并给出了解决方案.在指导学生做该实验时,要求学生来完成这个设计,可以帮助学生理解单臂电桥测量电阻的原理.     

有效衔接基础性实验与设计性实验的探究

引导学生利用现有仪器和原理,将常规基础性实验"惠斯登单臂电桥测电阻"改进为"利用单臂电桥非平衡性测电阻"的设计探索性实验,强化对学生创新精神和研究能力的培养,为开展后面更高层次的设计性实验奠定基础,从而形成基础性实验与设计性实验合理过渡、有序衔接的实验教学体系。     

单臂电桥测电阻灵敏度探析

单臂电桥测电阻是测量中值电阻的比较好的测量方法,但是测量精确度受到灵敏度的影响。文章中主要通过实验探讨了电源电动势、倍率以及电路电流对单臂电桥灵敏度的影响,并进行了分析讨论。实验结果证明,电桥灵敏度与电源电动势成正比,与4个桥臂电阻的搭配有关,随电流的增大而增大。     

大学物理实验课程问卷调查及改革实践

为提高大学物理实验教学质量,实验中心对大学物理实验课程进行了问卷调查,分析和总结了实验预习、教学指导、操作、报告等实验教学环节出现的问题.以问卷调查结果为课程改革依据,提出了将信息技术深度融合实验教学的改革方案.建设微信公众教学平台和虚拟仿真教学平台,辅助实验预习;建立以学生合作学习模式为主,教师指导为辅的教学指导模式,建立在线答疑学习群,全程覆盖课程答疑.有针对性地解决传统教学模式各环节出现的问题,提高了大学物理实验教学质量和水平.     

Violin frequency response - bridge mobility and bridge feet distance

Good violins have a broad hill in the 2-3 kHz range of their frequency response. This hill has previously been attributed to the first in-plane resonance of the violin bridge. Experiments prove, however, that the hill is the result of two forces acting in opposite directions at the bridge feet. The experiments reported here show that the hill can be “tuned” by altering the distance between the bridge feet. It can be tuned both in terms of frequency and level but the properties of the violin cannot be neglected.     

多功能数字滑触电桥

阐述了“多功能数字滑触电桥”的设计原理、前面板及实际应用。     

电桥实验的改革尝试

随着数字仪表的飞速发展和大量普及，以及非平衡电桥在传感技术中的广泛应用，有必要对电桥实验内容进行改革，我们把传统的平衡电桥实验改为非平衡电桥实验，从理论和实验上研究了非平衡电桥的工作特性和应用．     

高级数字式开尔文电桥

阐述了“高级数字式开尔文电桥”的设计原理、前面板及实际应用。     

Microstrip superheterodyne coherent microwave bridge

Reasons for unsatisfactory operation of the superheterodyne spectrometers at increased microwave power are considered. Recommendations for designing the superheterodyne microwave bridge of the EPR spectrometer working at the microwave power of about hundreds of milliwatt are given. These recommendations allow one to develop the spectrometer comparable to those with modulation of resonant conditions concerning reliability, stability and simplicity of operation. The experimental prototype of the coherent microwave bridge of the X-band superheterodyne EPR spectrometer with the intermediate frequency of 100 MHz is described. The microwave circuit of the bridge is assembled using microstrip hybrid integrated circuits and requires no adjustment in operation. The microwave Gunn-diode generators with the electronic tuning stabilized by dielectric resonators are used. The dynamic range of 54 dB at the maximum power of 40 mW is reached. As the microwave power increases up to the maximum value, no tendency to the degration of sensitivity equal to 5·10^?11 W at the 40 MHz band is noticed.     

The violin bridge as filter

The violin bridge filter role was investigated using modal and acoustic measurements on 12 quality-rated violins combined with systematic bridge rocking frequency f(rock) and wing mass decrements deltam on four bridges for two other violins. No isolated bridge resonances were observed; bridge motions were complex (including a "squat" mode near 0.8 kHz) except for low frequency rigid body pivot motions, all more or less resembling rocking motion at higher frequencies. A conspicuous broad peak near 2.3 kHz in bridge driving point mobility (labeled BH) was seen for good and bad violins. Similar structure was seen in averaged bridge, bridge feet, corpus mobilities and averaged radiativity. No correlation between violin quality and BH driving point, averaged corpus mobility magnitude, or radiativity was found. Increasing averaged-over-f(rock) deltam(g) from 0 to 0.12 generally increased radiativity across the spectrum. Decreasing averaged-over-deltam f(rock) from 3.6 to 2.6 kHz produced consistent decreases in radiativity between 3 and 4.2 kHz, but only few-percent decreases in BH frequency. The lowest f(rock) values were accompanied by significantly reduced radiation from the Helmholtz A0 mode near 280 Hz; this, combined with reduced high frequency output, created overall radiativity profiles quite similar to "bad" violins among the quality-rated violins.     

利用直流电桥测量电容

采用改进的直流电桥电路测量电容,避免了采用交流电源的不便以及因分布电容而带来的测量误差,并且测量工作简便易行.     

四端纳米分子桥的量子传输特征

利用基于Greenfunction的Tight-binding方法，对由平面共轭分子连结而成的有四个端子的纳米分子桥进行了理论研究和数值模拟，得出了入射电子通过纳米分子桥传输到各个端点的电子透射概率.利用Fisher-Lee关系式和电子流密度理论，在透射概率出现峰值的四个能量点E=±12,E=±149处计算了分子桥内的电子流分布.不仅得出了键电子流的最大值，而且揭示了分子内环路电子流生成和存在是由于分子轨道波函数的位相差使电子流的大小和方向发生变化而引起的. 关键词： 纳米分子桥 量子传输 电子透射概率 环路电子流     

多端耦合量子点分子桥的量子输运特性研究

利用非平衡格林函数方法,对五个量子点连结而成的有四个终端的耦合量子点分子桥进行了理论研究和数值模拟,得出了入射电子通过耦合量子点分子桥传输到各个终端的电子隧穿概率的规律. 关键词： 耦合量子点分子桥 非平衡格林函数 量子输运     

Sonic boom effects on circular bridge panels

This paper deals with the response of a curved bridge deck to sonic boom loading. The curved panel is considered as an annular sector plate with the two radial edges simply supported and the circular edges free. The method is equally applicable to other edge conditions. The normal mode method of analysis is used. The response to various durations of boom period as well as different pulse shapes has been determined and presented in the paper.