Volumetric slice plot : 'Slice' Function (error:Input grid is not a valid MESHGRID.)

I am having trouble producing 3d plot using 'slice' function.It is giving me a 'not a valid meshgrid error'.and also 'silce' function error.here is my code:

if true
  % code
end
R= linspace(0.14,0.28,100);
THETA= linspace(0,360,100);
Phi= linspace(90,-90,100);
[r,theta,phi]= meshgrid(R,THETA,Phi);
[X,Y,Z] = sph2cart(theta,phi,r);
t=(abs(sqrt(X.^2 + Y.^2+ Z.^2)));
beta=atan2d((sqrt(Y.^2+ Z.^2)),X);
A=(t/0.06)-(cosd(beta)/2);
B=(t/0.06)+(cosd(beta)/2);
C=((t).^2);
D=times((t),0.06*cosd((beta)));
E=((C+D+(((0.06).^2)/4)).^-1.5);
F=((C-D+(((0.06).^2)/4)).^-1.5);
H=times(A,E);
I=times(B,F);
V=0.2*(H-I);
xslice=0;
yslice=0;
zslice=0;
slice(X,Y,Z,V,xslice,yslice,zslice);