箱式电位差计测干电池电动势的误差分析

用电位差计测电源电动势是大学物理实验中一个典型的电学实验,由于运用到了补偿法测量原理使测电动势的精确度提高．电位差计不仅可以用来精确测量电源电动势,还可用来测量电流、电阻等等,由于其在工程领域里的广泛应用,电们差计实验是工科学生在大学中常做的大学物理实验之一．     

用电压表代替电位差计精测电阻

用电压表代替电位差计精测电阻吴文旺（石家庄铁道学院０５００４３）电位差计是精确测量电压（电动势）的仪器，其主要优点是用补偿法，消除用一般电压表测量时因内阻而带来的接入误差，相当于内阻“无穷大”．电位差计精测电阻的线路如图１所示，分别测得标准电阻凡和待...     

用伏特计测电源电动势

提出一种测量电源电动势的方法，即用伏特计代替电位差计测量电源的电动势和内阻。     

简易式毫伏级待测电动势实验仪的设计及其稳定性的研究

设计了简易式待测电动势实验仪,并对其稳定性进行了研究;通过改变待测电动势实验仪测量端电阻的大小来实现输出电动势的变化,输出的毫伏级电动势在电位差计实验仪的各个测量点非常稳定,能够满足箱式电位差计测量范围和精度要求,是非常理想的箱式电位差计实验配套仪器。     

用板式电位差计实验系统与SPSS标定电池的电动势

针对板式电位差计测量电池电动势的实验装置,以电池的电动势为研究对象.用补偿法测量实验数据.引入SPSS的曲线估计功能,得到标准电池电动势和长度的复合量与有效长度量的定标曲线,并验证出标准电池电动势和长度的复合量与有效长度量存在线性关系,由此标出待测电池的电动势,用置信概率为95％的不确定度,对实验结果进行分析和评价,最终得到更为直观的、合理实验结果.     

用自组电位差计测干电池电动势和内阻

根据电压补偿原理，设计了自组电位差计的几种实验电路，用于测量干电池的电动势和内阻。     

LED毫伏级待测电动势实验仪的设计及其稳定性的研究

为了满足电位差计实验对毫伏级待测电动势需求,设计了LED毫伏级待测电动势实验仪,并对其稳定性进行了研究.待测电动势实验仪是通过光电转换来实现的,输出的毫伏级电动势在电位差计实验仪的各个测量点都能稳定,能够满足箱式电位差计测量范围和精度要求,是比较理想的箱式电位差计实验配套仪器,能够大大提高学生的实验效率和教师对实验设计的选择性,实验效果良好.     

补偿法的电路分析

本文分析了用电位差计测量电源电动势的几种补偿法线路，比较优、缺点，说明如何选取最佳方案达到测量精度的要求。     

“电位计测电动势实验”中的几个问题的讨论

电位计是电测量中精确度高、用途广的重要仪器。在普通物理实验教学中,普遍采用的是结构简单直观的滑线电位计。电位计测电动势是采用所谓“补偿法”,它是以被测电池的电动势与电阻上的已知电压降相互平衡这一原理作为基础的。图1为其原理     

智能型电位差计的设计与研究

介绍了采用先进的电子技术设计出新型高精度的电位差计，该食品电子线路用高稳定性可调电源取代传统电位差计的干电池和标准电池，用高灵敏度的电子检流计取代机械检流计，配上单片机，通过对可调电源的测量，转换成对被测物理量的测量，即可精确的测量出待测电动势值。     

The Chemical Potential

The definition of the fundamental quantity, the chemical potential, is badly confused in the literature: there are at least three distinct definitions in various books and papers. While they all give the same result in the thermodynamic limit, major differences between them can occur for finite systems, in anomalous cases even for finite systems as large as a cm³. We resolve the situation by arguing that the chemical potential defined as the symbol μ conventionally appearing in the grand canonical density operator is the uniquely correct definition valid for all finite systems, the grand canonical ensemble being the only one of the various ensembles usually discussed (microcanonical, canonical, Gibbs, grand canonical) that is appropriate for statistical thermodynamics, whenever the chemical potential is physically relevant. The zero–temperature limit of this μ was derived by Perdew et al. for finite systems involving electrons, generally allowing for electron–electron interactions; we extend this derivation and, for semiconductors, we also consider the zero–T limit taken after the thermodynamic limit. The enormous finite size corrections (in macroscopic samples, e.g. 1 cm³) for one rather common definition of the c.p., found recently by Shegelski within the standard effective mass model of an ideal intrinsic semiconductor, are discussed. Also, two very–small–system examples are given, including a quantum dot.     

SERS谱峰强度比与电位的关系

ＳＥＲＳ谱峰强度比与电位的关系顾仁敖，吴芸，乔专虹，姚建林（苏州大学化学系２１５００６）田中群，李五湖（厦门大学化学系３６１００５）ＴｈｅＤｅｐｅｎｄｅｎｃｅｏｆＴｈｅＳＥＲＳＩｎｔｅｎｓｉｔｉｅｓＲａｔｅｏｎＴｈｅＰｏｔｅｎｔｉａｌ￥ＧｕＲｅｎａｏ...     

电势叠加原理与点电荷电势的普适表示式

用电势叠加原理求无限大带电体电势的问题,通常所用的(这里讨论真空情况)电势叠加原理表示式为 　　……     

The Immersed Structural Potential Method for haemodynamic applications

In this paper, a new fluid–structure interaction immersed computational methodology, based upon the original Immersed Boundary Method (IBM) [1] is outlined with the final aim of modelling cardiovascular phenomena, specifically, heart valve related problems. The principal characteristic of such immersed techniques is the representation of any deformable or rigid body immersed within an incompressible viscous flow field as a momentum forcing source in the Navier–Stokes equations. A number of shortcomings within the immersed formulation still require further investigation and improvement, including the excessive numerical diffusion caused by the interpolation/spreading process, the need to include realistic viscoelastic composite constitutive models describing more accurately the nature of cardiovascular tissues and also the need to capture more effectively stresses developed at the fluid–structure interface. By following the same philosophy as the original IBM, a more sophisticated formulation is derived in this paper, the “Immersed Structural Potential Method (ISPM)”. The method introduced presents an alternative approach to compute the equivalent fluid–structure interaction forces at the fluid mesh, accounts for a sophisticated viscoelastic fibre-reinforced constitutive model to better describe the mechanics of cardiovascular tissues and utilises a novel time-integration methodology for the computation of the deformation gradient tensor which ensures compliance with the incompressibility constraint. A series of numerical examples will be presented in order to demonstrate the robustness and applicability of this new methodology.     

The Two-Nucleon Stripping Process with Skyrme Type Potential

Theory of two-nucleon stripping reactions is reconsidered. The nucleon-nucleon interactions are taken as Skyrme type potentials. Differential cross-sections for two-nucleon stripping reactions are calculated using DWBA approximation with different Skyrme type potentials of different parameters. The angular distributions for different two-nucleon stripping reactions (t, p) with incident triton on the different targets of ³¹P, ⁴⁰Ca, ⁹⁶Zr, ¹¹⁸Sn and ²⁰⁶Pb are calculated giving good agreement with the experimental data. Better values are extracted for the spectroscopic factors.     

是电势差还是电动势

我院使用的上海版大专《物理学》第七章，有三道题值得商量，其中一道如下．长直载有电流，的导线一侧的同一平面上，有一段导线MN，它与直导线的垂直方向成θ角，其尺寸与位置如图所示，当它以平行长直导线方向作匀速率v运动时，MN两点间电势差多大?哪一点电势高?     

PuH3分子的几何构型及基态附近势能特征计算

目前还没有关于PuH₃的分子结构和分子光谱公开解密的资料与数据.基于密度泛函理论的全数值自洽场计算方法——离散变分方法(DVM),数值解相对论Dirac方程,在自由的钚原子和氢原子波函数的数值基及原子能级基础上计算了PuH₃分子的不同几何结构及势能曲线.等边三角棱锥形PuH₃分子基态的数据为:Pu-H键长=2.097726Å,键角θ(H-Pu-H)=119.102Å,H-H距离为3.616817Å,轨道总能量为-19869.834a.u.,费米能级E_f=-16.856eV.分析了反演对称等价的分子态以及非质心坐标对轨道总能量的影响.比较了PuH₂和PuH₃分子参数的全电子计算结果.     

The self-consistent condition for the cranked Harmonic Oscillator Potential

When the nuclear field is approximated by an Harmonic Oscillator Potential it is possible to obtain an exact solution when the field is cranked with frequency ω. We have shown that when the energy is minimized, subject to the condition of constant volume, the square of the velocity distribution is not isotropic as previously assumed. The system shows greater stability resulting in a higher cut-off frequency and an expanded energy spectrum.     

The Soft-Core Coulomb Potential in the Semi-Relativistic Two-Body Basis

We consider the soft-core Coulomb potential within a semi-relativistic two-body framework which arises from the spinless Salpeter equation after some approximations valid for heavy interacting particles. To provide an analytical solution, we propose a novel ansatz solution to the arising Schrödinger-like equation and thereby obtain the ground-state energy. Our results, for the special case of ordinary Coulomb potential, are in complete agreement with the corresponding exact analytical solution. The spectrum is numerically reported for typical values of the potential parameters.     

含时库仑势和线性势的薛定谔方程的求解

利用Burgan等人的时空变换方法对一类特殊形式的具有含时库仑势加线性项的薛定谔方程进行了分析和计算,并进一步讨论了更普遍形式的含时势V(r,t)=–a0ξ12r+nk=1akrkξk2+1(其中ξ=at2+bt+c,a0,a1,a2,…,an,a,b,c是满足一定关系的常数)的波函数