Problem with meshgrid and 3D graphics

Hello i have this script and i want to realize a 3d graphics

t=logspace(-2,3.5,100);
r= 400 * 1e-6:2:600 * 1e-6;
[R,T]= meshgrid(r,t);
RIC = 100;
kf = 0.2;
kr = 10;
rn = 10 * 1e-6;
D = 2100 * 1e-12;
Q = 2.5e4;
v = (4/3) * pi * (rn^3);
y = ((Q ./ ((4*pi*D.*T).^(3/2)) ) .* (exp(-(R^2)./(4*D.*T)))) * v;
a = kf*RIC*exp(-kr*T);
z = conv(y,a);
hSurface=surf(R,T,z);
set(hSurface,'LineStyle','none');
colorbar;
title('Valore della concentrazione massima in funzione del numerodi molecole e della distanza','FontSize',15)
ylabel('TEMPO','FontSize',15);
xlabel('DISTANZA','FontSize',15);
zlabel('Concentrazione [mol/\mum^3]','FontSize',15);
set(gca,'FontSize',14);
grid on

But there are these mistakes: ??? Error using ==> surf at 78 Z must be a matrix, not a scalar or vector.

Error in ==> prova at 14 hSurface=surf(R,T,z);

Error in ==> prova at 11 y = ((Q ./ ((4.*pi.*D.*T).^(3/2)) ) .* (exp(-(R^2)./(4.*D.*T)))) .* v;

Answer 1

[Star Strider]

Your ‘r’ variable needs to be a vector in order for meshgrid to produce matrix outputs.

It is currently a scalar.

[loredana]

I don't know matlab very well... how can i resolve this problem?

[Star Strider]

I have no idea what you’re doing, so I can’t be specific. You simply have to create a vector for it.