lost atoms in SiO2 simulations by BKS potential

Hi, everyone, the SiO2 substrate was simulated by using BKS potential. However, atoms always lost in my simulation. Can you give me some suggestions for this problem. The input script and data file are as bellow:

dimension 3
boundary p p p
units real
atom_style full

read_data data.sio2

Buck potentials

pair_style hybrid buck/coul/long 11.0 lj/cut 12.0
kspace_style pppm 1.0e-4
kspace_modify mesh 24 24 30 order 6
pair_coeff 1 1 buck/coul/long 32007.28 0.3623 4035.5
pair_coeff 1 2 buck/coul/long 415172.24 0.2235 3078.51
pair_coeff 2 2 lj/cut 0.0 0.0

neighbor 2.0 bin
neigh_modify every 1 delay 0 check yes

velocity all create 300.0 9999999 rot yes dist gaussian

fix 1 all nvt temp 298.15 298.15 20 drag 0.02
restart 50000 restart.*.zuizhong
timestep 0.001

thermo_style custom step temp press etotal ke pe
thermo 10
dump 1 all custom 10 dump.sio2 type x y z
run 100000

data file :

LAMMPS Atom File)
8100 atoms
0 bonds
0 angles
0 dihedrals
0 impropers
2 atom types
0 bond types
0 angle types
0 dihedral types
-38.6447 75.26343 xlo xhi
-3.0 66.14413 ylo yhi
-3.0 23.97867 zlo zhi
-27.6453 0.0 0.0 xy xz yz
Masses
1 15.9994
2 28.0900

Atoms
1 1 1 -1.2 -0.280434837 1.762907387 0.62933
2 1 1 -1.2 1.068492788 3.127863797 4.230663333
3 1 1 -1.2 -0.788057951 3.613591183 2.429996667
4 1 1 -1.2 1.66694 0.63859 4.77267
5 1 1 -1.2 2.174563113 2.489273797 1.171336667
6 1 1 -1.2 3.523490739 1.124317387 2.972003333
7 1 2 2.4 1.180315677 2.044366722 0
8 1 2 2.4 2.549364547 0 3.601333333
9 1 2 2.4 -1.274682273 2.207814461 1.800666667
10 1 1 -1.2 4.629561064 1.762907387 0.62933

Yours sincerely,
Jane

Hi, everyone, the SiO2 substrate was simulated by using BKS potential.
However, atoms always lost in my simulation. Can you give me some
suggestions for this problem. The input script and data file are as bellow:

this is a question about something that is well documented and often
explained on this mailing list, so how about doing this?

http://lmgtfy.com/?q=lammps+lost+atoms

too obvious??

axel.

Dear Axel, I am sorry for disturbing you with the similar question. Thanks very much for your suggestions. Best wishes!
yours sincerely,
jane