A dislocation reaction in the face-centred cubic lattice
A dislocation reaction in the face-centred cubic lattice
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DOI：
10.1080/14786444108561389
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发表时间：
1951-11
期刊：
影响因子：
--
通讯作者：
W. Lomer
中科院分区：
文献类型：
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作者：
W. Lomer
In~r~--=-1.32by In~2~=1.28，即相差4%。最后，用~‘lnx-~-4--z C/C=1--~.%%~7r(7)代替Wohlfarth的比热公式(2-8)，其中Co是Sommerfeld比热1~2Nk(KT/%)。这又相当于用lnTr-t-1/2取代Ln2？7/12。这再次证实了交换能的加入大大降低了比热的结果。因为从(4)和(6)中可以清楚地看出，作为T-->；0，x~0和从(7)中，作为x--~0，C/C-->；0。用一阶和二阶变分函数得到的结果之间的这种紧密的一致性是变分方法有效性的有力证据。对于没有交换作用的理想费米-迪拉克气体，热力学函数的近似值和精确值的比较证实了这一点(在别处发表，Lidiard 1951)。
In~ r~~--=-1.32 by In 2~= 1.28, ie a difference of 4 per cent. Finally, Wohlfarth's equation (2-8) for the specific heat, C, is replaced by~'ln x---~-4--z C/C= 1--~.%%~ In 7r(7) where C o is the Sommerfeld specific heat ½~ 2Nk (kT/%). This again is equivalent to the replacement of ln2÷ 7/12 by lnTr-t-½--~/2. This reaffirms the result that the specific heat is greatly decreased by the inclusion of the exchange energy. For it is clear from (4) and (6) that as T--> 0, x~ 0 and from (7) that as x-~ 0, C/C--> 0. This close agreement between the results obtained by using the first and second order variation functions is strong evidence for the validity of the variation method. This is confirmed by a comparison of the approximate and exact values of the thermodynamic functions for a perfect Fermi-Diracgas without exchange interactions (published elsewhere, Lidiard 1951).