N. M. Khutoryansky, V. Genis
876
in 3-D case described in [15] reduces to the following expression for the dis-
placement component
:
( ) ( ) ( )
( )
( ) ( )
( )
( ) ( )
( ) ( )
/
0
1
, 0, ,
2
1
0, 0, d
2
1
, ,d
2
1
, , d d in ,
2
t xc
t hxc
h t xc
u xt u t xc u ht h x c
e
D
c
e
h Dh
c
e
bq
c
ξ
στ τ τ
ρ
στ τ τ
ρ
ξτ ξτ τ ξ
ρ
−
−∞
−−
−∞
−−
−∞
= − + −−
−+
++
+ −Ω
∫
∫
∫∫
(8)
where
is denoted by
and it is taken into account that the outward
normals to the lower and upper boundaries of the layer
have opposite
directions.
In many practical applications, the electric volume charges are absent. There-
fore, we consider henceforth only the case when
. Then the terms related
to
in the above expression can be simplified since, based on Equation (4) in
this case,
is spatially uniform:
(9)
Due to the property (9) the representation formula (8) can be rewritten as
( ) ( ) ( )
(
)
( ) ( )
( )
( ) ( )
( )
0
1
, 0, ,
2
1
0, d
2
1
,d
2
1
, d d in .
2
t xc
t hxc
h t xc
u xt u t xc u ht h x c
e
D
c
e
hD
c
b
c
ξ
στ τ τ
ρ
στ τ τ
ρ
ξτ τ ξ
ρ
−
−∞
−−
−∞
−−
−∞
= − + −−
−+
++
+Ω
∫
∫
∫∫
(10)
To obtain a representation formula for
, let us consider an auxiliary
function
( ) (
) (
)
,, ,
e
xt xt u xt
ψφ
= −
(11)
that has the following connection to the electric displacement:
According to (3),
. Then, using the corresponding Green’s
function
and Equation (11), we get a representation formula for
involving only boundary value of function
and a spatially uniform
electric displacement:
( ) ( ) ( )
( )
12
, 0, , in .
22
hx
xt t ht D t
ψ ψψ
−
= ++ Ω
(12)
Formulas (12) and (11) lead to the following expression for
:
( ) ( ) (
) ( ) ( )
( )
( )
1
, 0, , 0, ,
22
2
, in .
2
e
xt t ht u t u ht
e hx
u xt Dt
φ φφ
= +− +
−
++ Ω
(13)