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A .cos ( k .r .a
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2 .π
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2
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10
12
14
16
18
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2
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6
8
10
12
14
16
18
20
2 .π 6 .a 1
0
1 0
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beadxmp.mcd
1
04/02/99 16:26
k
2 .π 2 .a
1
0
1 0
2
4
6
8
10
12
14
16
18
20
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beadxmp.mcd
2
04/02/99 16:27
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