# Query about the in.noGB_small

Hello，Thank you for your help.In the past few days,I have read the docs carefully and I really have done my best .However,I still have the question about the units .For example ，the command “fix_modify AtC transfer fix_flux temperature lbc 0.00000001” and “fix_modify AtC transfer fix_flux temperature rbc -0.00000001” which are in the input in.noGB_small.My computational process is below.Please help me to check up it. I’m very grateful !

Computational process:
The heat flux units is w/m/m.
w=J/s J=Nm N=Kgm/s/s
w/m/m=Kg/s/s/s
1Kg=10006.0210^23(amu)
1s=10^15(fs)
w/m/m=10006.0210^23/10^45(amu/fs^3)=6.0210^(-19)(amu/fs^3)
So,the 3.32
10^9(w/m/m)=3.3210^96.0210^(-19)=1.9986410(-9)(amu/fs^3).But the result is not equal to the 0.00000001 in the command above.Can you please tell me where the error is?

In additional , I have some new questions .I’m very puzzled .Please help me !!

Q1:In the atc ，when I apply the Dirichlet boundary condition.How to compute the heat flux in the overall system? Which command can be used ?Can the command “compute heat/flux” be used ?

Q2: In the example 5.1(Templeton et al), the heat flux is computed by the formula "total power/cross sectional area =heat flux ". Can you please tell me how to compute the total power ?

Q3:In a simulation,I found the temperature in the FE region which is near to the hot region is lower than the temperature in the MD region which is near to the cool region. Is it wrong ? Why ?

Q4: In the command "fix_modify AtC transfer boundary type " ,Can the option include two kinds of atom style ? Because I want to simulate the composite material .

Q5:In the last talk, I found the command "fix_modify AtC reset_time " .Is it a new command ?

Q6: In the atc simulation , after the system is equilibrium , we apply the fixed temperature or heat flux boundary condition .Then how to judge if the system is steady?

Thanks in advance . I’m very grateful for your help.

Best regards !

wangdan