constant.m

来自「航天工程工具箱」· M 代码 · 共 48 行

function [n,u]=constant(c)
%CONSTANT  Get physical constant.
%   [N,U] = CONSTANT(C) retreives the constant C (string)
%   and returns its value to N. The optional output U is
%   the unit of the constant (in SI).
%
%   See also CONVERT.

% Copyright (c) 2001-12-08, B. Rasmus Anthin.
% Revision 2002-12-31, 2003-01-06, 2003-04-22.

switch c
case {'T0','T_0'}
   n=273.15;
   u='K';
case {'c','c0'}
   n=299792458;
   u='m/s';
case {'mu0','u0'}
   n=4*pi*10^-7;
   u='Vs/Am';
case {'epsilon0','eps0','e0'}
   n=1/(299792458^2*4*pi*10^-7);
   u='As/Vm';
case 'G'
   n=6.67259e-11;
   u='Nm^2/kg^2';
case 'g'
   n=9.80665;
   u='m/s^2';
case {'me','m_e'}
   n=9.109390e-31;
   u='kg';
case {'mmu','m_mu'}
   n=1.883533e-28;
   u='kg';
case {'mp','m_p'}
   n=1.672623e-27;
   u='kg';
case {'mn','m_n'}
   n=1.674929e-27;
   u='kg';
case {'re','r_e'}
   n=2.817941e-15;
   u='m';
case 'a0'
   n=.52917725;
   u='