交流电桥实验分析与研究

针对交流电桥实验中学生很困惑的三个问题进行分析和讨论，即：电桥平衡时应满足灵敏阈小于基本误差的1／10；交流电桥工作频率定为1000HZ；磁介质电感测量值与工作电流密切相关．     

不平衡电桥法电池内阻测量装置的原理与设计

介绍不平衡电桥法测量电池内阻装置的原理及设计,不平衡电桥法测量电池内阻利用电池本身的电动势在电一对对解点间产生的直流电压,在给定条件下不随另一对对角点间放电电流大小变化的特点构成的,测量装置不需在电桥上施加信号源,电桥的平衡指示信号取自对角点电压及等效电阻的变化成分。     

非平衡纯电阻电桥等效电阻的一种特殊计算

用分割电阻法构造出非平衡电阻电桥的特殊串联与并联组合的混联电路后,应用串、并联电路的电流特点和电压特点,巧妙导出了非平衡电阻电桥(非串联又非并联电阻组成的复杂电路)的等效电阻.     

分别平衡电阻和电抗分量的交流电桥

本文讨论交流电桥分别平衡原理.采用分相电路和双相敏检波电路,引入交流电桥等效电流概念,得出了分别平衡方程.由桥臂中可调电阻上引出相敏检波参考电压,在平衡过程中能自动跟踪相位变化,使电桥电阻分量和电抗分量可以分别平衡.一、引言交流电桥的平衡,可借助于指零器,用反复调节可变参数的方法来达到.这一过程往往是很长的,也是很费力的,要求操作者有一定的技巧和经验.当电桥收敛性很不好时,可能     

非平衡直流电桥的原理和应用探究

非平衡直流电桥是直流电桥的一种,作为一种精密的电阻测量仪器,它在生活中具有重要的应用价值。本次实验根据非平衡直流电桥的基本原理,测量电桥输出的电压和电流,通过数据分析处理得出电阻在不同温度下的变化规律。结果表明:在处理铜电阻数据时应该满足条件△R〈〈R(R为待测导体电阻阻值,△R为电阻变化量)下的公式处理数据,在处理热敏电阻数据时用不满足条件△R〈〈R下的公式处理数据,能减小误差,得到更为精确的结果。同时也证明了卧式电桥、等臂电桥的输出电压都比立式电桥高,即灵敏度也高,但是立式电桥的测量范围大。     

电桥伏安法测电阻

电桥伏安法测电阻王新生（南京建工学院２１０００９）一、引言伏安法测电阻是一个重要的基础实验，是用电压表和电流表测出电阻尼两端的电压Ｖ和流过电阻Ｒｘ的电流Ｉ，然后利用欧姆定律Ｒｘ＝Ｖ／Ｉ（１）计算出电阻Ｒｘ的值．伏安法测电阻的传统测量方法是内接法和外接...     

电子示波器在交流电桥中的一种应用方法

电子示波器用在交流电桥中作为平衡指示器时,通常在一对偏转钣极上加上电桥对角线的电压,而在另一对偏转钣极上加上铺助电压,这电压几乎完全是不固定的,这样不仅效果不高,调节电桥平衡也需时较多。利用电子示波器的相敏性质,用所谓交流电桥分离平衡的方法,可以加速平衡的调节。     

直流电桥测自感系数

自感系数(簡称自感)的測定,一般采用交流电桥,作者設計了一种使用直流电源的电桥测定方法,此法簡单,而且比較直观。茲介紹如下,供参考: 测量电路如图1所示,測法如下: 一、閉合开关K,調D的位置,使电桥平衡(即使通过电流計G的电流等于零)。     

惠斯登电桥法研究静电场的描绘

电流场模拟静电场实验是《大学物理实验》中的一个重要内容。一般教材采取利用直流电压表测量探针和外电极之间电压的方法来描绘长同轴圆柱形电缆的等势线分布。本论文将采用惠斯登电桥法对其等势线分布进行测量,并且与电压表和数字万用表测量的结果及理论值进行比较。     

惠斯通电桥的理论研究

本文从电源内阻ｒ不等于零，及不对桥臂电阻作任何限制性假设的最一般情形出发，解出非平衡电流，证明了检流计的电流灵敏度与其平均等效内阻Ｒｇ的平方根成正比。指出，只当电源和桥臂线路作为一等效电压源的内阻等于Ｒｇ，且桥臂电阻满足电桥平衡条件下的一定极限关系时，电桥灵敏度才有极大值，进而给出个电桥最大灵敏度的普遍表达式，并提出了惠斯通电桥用于测电阻时选择电路参数的一般步骤和方法。     

初级能量平衡

针对“神光Ⅱ”精密化的要求，有用半波片和偏振片组合衰减装置精确控制光束能量，达到能量平衡。简要论述了半波片组合衰减器的工作原理。采用独特的方法，对高精度光电探头和半波片的特性进行了检测。在此基础上，运用自动控制技术进行智能调节，实现了闭环自动控制模拟实验，达到了均方根为２％的激光能量控制精度。     

整体旋转式斯特林制冷机平衡块设计

为了减小整体旋转式斯特林制冷机运行过程中曲柄连杆机构产生的不平衡惯性力,建立了制冷机三维模型。对制冷机机构进行分析;运用CAE软件对制冷机工作时的运动进行动力学仿真。计算出制冷机运行过程中产生的不平衡力,通过设计优化平衡块的质量减小曲柄连杆运动过程中产生的不平衡惯性力,并为制冷机设计优化方法。     

Balance functions at RHIC

The balance function is based on the principle that charge is locally conserved when particles are pair produced. Balance functions have been measured for all charged pairs, identified pion pairs, and identified charged kaon pairs in Au+Au collisions at $\sqrt {s_{NN} } = 200$ GeV and p+p collisions at $\sqrt {s_{NN} } = 200$ GeV at the Relativistic Heavy Ion Collider using STAR. Balance functions for all charged particles from Au+Au scale smoothly with centrality to the p+p value. Balance functions for charged particles and pions are narrower in central collisions than in peripheral collisions consistent with trends predicted by models incorporating the concept of late hadronization. Balance functions for kaon pairs represent a strangeness balance. Balance functions for kaons are narrower than those for pion pairs and may show less dependence on centrality.     

Structural Balance of Opinions

The concept of Heider balance, usually applied to interpersonal relations, is generalized here to opinions gathered in surveys. At first, we compare four algorithms, which drive a matrix dataset to a balanced state. The criterion is that the final state obtained with an algorithm should be as close as possible to the initial state. The result is that deterministic differential equations work better than their Monte Carlo counterparts. Next, we apply the winning algorithms to the matrix of correlations between opinions gathered in American states between 1974 and 1998. The results are interpreted in terms of the classic comfort hypothesis (E. Babbie, 2007).     

Aging Effects on the Structure Underlying Balance Abilities Tests

Balance impairment is one of the biggest risk factors for falls reducing inactivity, resulting in nursing care. Therefore, balance ability is crucial to maintain the activities of independent daily living of older adults. Many tests to assess balance ability have been developed. However, few reports reveal the structure underlying results of balance performance tests comparing young and older adults. Covariance structure analysis is a tool that is used to test statistically whether factorial structure fits data. This study examined aging effects on the factorial structure underlying balance performance tests. Participants comprised 60 healthy young women aged 22 ± 3 years (young group) and 60 community-dwelling older women aged 69 ± 5 years (older group). Six balance tests: postural sway, one-leg standing, functional reach, timed up and go (TUG), gait, and the EquiTest were employed. Exploratory factor analysis revealed that three clearly interpretable factors were extracted in the young group. The first factor had high loadings on the EquiTest, and was interpreted as ‘Reactive’. The second factor had high loadings on the postural sway test, and was interpreted as ‘Static’. The third factor had high loadings on TUG and gait test, and was interpreted as ‘Dynamic’. Similarly, three interpretable factors were extracted in the older group. The first factor had high loadings on the postural sway test and the EquiTest and therefore was interpreted as ‘Static and Reactive’. The second factor, which had high loadings on the EquiTest, was interpreted as ‘Reactive’. The third factor, which had high loadings on TUG and the gait test, was interpreted as ‘Dynamic’. A covariance structure model was applied to the test data: the second-order factor was balance ability, and the first-order factors were static, dynamic and reactive factors which were assumed to be measured based on the six balance tests. Goodness-of-fit index (GFI) of the models were acceptable (young group, GFI=0.931; older group, GFI=0.923). Static, dynamic and reactive factors relating to balance ability had loadings 0.21, 0.24, and 0.76 in the young group and 0.71, 0.28, and 0.43 in the older group, respectively. It is suggested that the common factorial structure of balance abilities were static, dynamic and reactive, and that for young people reactive balance ability was characterized and explained by balance ability, whereas for older people it was static balance ability.     

Remarks on the Energy Balance of Low Pressure Discharges

Including excitation and de-excitation processes, direct and stepwise processes of the ionization, the particle balance and the energy balance of a positive column are jointly studied. It is shown that even near the axis the energy flux due to the radial electron drift can be only neglected provided that the mean electron energy is considerably less than the ionization energy. In some cases, it appears easier to apply the total energy balance instead of the energy balance of the electron gas alone.     

Balance Equations for Quantum Tunneling

We have established a set of balance equations to demonstrate the hot electron effect in the quantum tunneling processes by using the well-known effective tunneling Hamiltonian model. The high field effects both in reservoirs and in barrier region are discussed in detail. We also find a new field-dependent characteristic time due to nonequilibrium of reservoirs (the left-and right-sides of the barrier region) in the double-barrier structure.     

Balance equations for micromorphic materials

The balance laws for micromorphic continua of degree 1 are derived by means of classical statistical mechanics. The equations derived by Eringenet al. [Continuum Physics, Vol. IV (Academic, New York, 1976)] are obtained in a slightly generalized form. Explicit expressions for the stress, the couple stress, the spin production, and the heat flux are given in terms of microscopical variables.     

可调平衡探测激光偏振光谱研究

偏振光谱技术是一种高灵敏度和高分辨的光谱技术.提出一种基于可调平衡探测偏振光谱的实验方法,研究了不同偏振面下偏振光谱线型的变化趋势,观测到光谱线犁随偏振片旋转产生的翻转现象.通过结合偏振理论与平衡探测理论,对线型翻转现象进行了解释,理论与实验符合得很好.同时,研究了色散型谱线峰峰值与抽运光强之间的依赖关系,发现在抽运探测光强比约为100时谱线强度出现饱和现象,为利用偏振光谱进行激光器频率稳定时选择参数提供了理论依据.