用Excel求方程的解

介绍用Excel求方程解的方法。     

硫化矿试金硝石法还原力的理论近似值计算

硫化矿中金银分析方法较多,试金硝石法被列为冶金部颁标准,其缺点是在每个试样调料前都必需进行还原力的试验.耗时长,成本高,虽在实际工作中可根据日常积累经验进行调料,但往往产生较大误差.本文根据硝石法的基本原理,即用硝石之氧化力来进行脱硫,使矿石中部份硫化物被氧化,残留的另一部分硫化物恰能还原氧化铅使生成25克左右的铅扣.探讨了从已知硫化矿中含硫、铅、锌、铁等成份计算理论还原力的近似值.其反应式及计算方法如下:     

浮点倒数查找表的构造

在浮点除法器的设计中，若用函数迭代或高基数算法进行除法运算，计算开始时，通过浮点倒数查找表获得一个较精确的初始除数倒数近似值，可以减少除法的迭代次数，缩短运算的延迟。即将除数的前几位作为表的一个入口地址，该地址指示的位置存放着满足一定精度的初值倒数近似值。文中详述了几种获得除数倒数近似值的方法，其中包括算法、误差限和精度等。     

标准椭圆形封头曲率半径的近似值

根据四心圆法做椭圆的基本原理归纳出了标准椭圆形封头曲率半径的近似值,从而简化了标准椭圆形封头的画法。     

Experimental study on size-dependency of effective permittivity of particle-gas mixture with agglomeration

The effective medium approximation （EMA） theory is the basis of a capacitance sensor used for concentration measurementof a particulate solid flow, its measurementresultis independenton particle size. In existence ofparticle agglomeration or aggradation, however, it is found that the effective permittivity of a gas/solid mixture is de-pendent on particle size. In this paper, a parallel plate, differential capacitance sensor is utilized to investigate theinfluence of particle size on the effective permittivity of the mixture in such a case. Static experiments using threematerials including glass, limestone and quartz particles were carried out in an off-line manner. The volume fractionof particles being tested ranged from20×10^-6to 600×10^-6, while the particle size was between 3 and 100μm.Experimental results showthat the effective permittivity of a particle-gas mixture with particle agglomeration is largerthan that predicted by EMA and the smaller the particle size, the larger the effective permittivity. The experimentprocess and analysis results are discussed in detail in the paper.     

Identification of Wiener systems with nonlinearity being piecewise-linear function

Identification of the Wiener system with the nonlinear block being a piecewiselinear function is considered in the paper, generalizing the results given by H. E. Chen to the case of noisy observation. Recursive algorithms are given for estimating all unknown parameters contained in the system, and their strong consistency is proved. The estimation method is similar to that used by H. E. Chen for Hammerstein systems with the same nonlinearity. However, the assumption imposed by H. E. Chen on the availability of an upper bound for the nonsmooth points of the piecewise-linear function has been removed in this paper with the help of designing an additional algorithm for estimating the upper bound.     

轴心受压焊接工字形柱截面合理选择

按照选择的整体稳定系数φ或长细比λ，在满足2个主轴整体稳定和截面局部稳定的条件下，借助于截面回转半径近似值及翼缘、腹板的经济面积比例，分析出轴心受压双轴对称焊接工字形柱截面宽度和高度的关系式，以及翼缘、腹板尺寸的计算公式，供设计时参考。     

Comparison of perturbation theory and mean spherical approximation based on molecular simulation data

A comprehensive study on various internal energies for the dipolar hard sphere fluids, including Stockmayer fluidst the mixtures of Lennard-Jones and Stockmayer and Stockmayer fluids and the electrolyte solutions is reported based on the perturbation theory and mean spherical ap-prcmimatlon. Compared with the results of molecular simullttions, it is shown that the perturbationtheory is better than the mean spherical approximation.     

Cylindrical Helix Spline Approximation of Spatial Curves

In this paper, we present a new method for approximating spatial curves with a G^1 cylindrical helix spline within a prescribed tolerance. We deduce the general formulation of a cylindrical helix, which has 11 freedoms. This means that it needs 11 restrictions to determine a cylindrical helix. Given a spatial parametric curve segment, including the start point and the end point of this segment, the tangent and the principal normal of the start point, we can always find a cylindrical segment to interpolate the given direction and position vectors. In order to approximate the known parametric curve within the prescribed tolerance, we adopt the trial method step by step. First, we must ensure the helix segment to interpolate the given two end points and match the principal normal and tangent of the start point, and then, we can keep the deviation between the cylindrical helix segment and the known curve segment within the prescribed tolerance everywhere. After the first segment had been formed, we can construct the next segment. Circularly, we can construct the G^1 cylindrical helix spline to approximate the whole spatial parametric curve within the prescribed tolerance. Several examples are also given to show the efficiency of this method.