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where
g
,
g
are the generalized galvanic parameters of the
3
- and
3
-segments:
S
S
1
R
2
S
s
=
S
S
3
S
S
1
R
2
S
3
=
S
S
3
g
=
g
=
g
g
(7
.
87)
1
√
S
1
R
2
g
=
Z
N
Z
N
are the normal impedances:
and
,
1
S
,
1
S
.
Z
N
=
Z
N
=
(7
.
88)
The generalized adjustment distances are
S
3
S
S
3
S
S
1
R
2
.
1
g
=
1
g
=
d
=
d
=
d
,
d
,
d
=
(7
.
89)
They differ from the standard adjustment distance
d
by factor depending on ratio
between
S
3
and
S
. The less the conductance
S
3
of sediments covered with highly
resistive layer, the less the generalized adjustment distance.
The coefficients
A
and
B
are determined from the conditions that
Z
⊥
and
dZ
⊥
/
|
|
=
v
. It is easy to show that these conditions provide
continuity of current densities
j
y
and
j
z
within the first and second layers.
On simple mathematics we obtain
dy
are continuous at
y
⎧
⎨
⎡
⎣
⎤
⎦
1
S
S
3
e
−
(
|
y
|−
v
)
/
d
−
|
| ≥
v
1
y
q
cot h
d
S
+
Z
⊥
(
y
)
⎡
⎤
=
(7
.
90)
⎩
1
S
1
sin h
d
S
3
y
d
⎣
⎦
|
1
+
cos h
y
| ≤
v,
S
cot h
d
q
+
where
S
S
S
3
S
3
S
S
S
3
S
3
S
3
−
S
3
,
q
=
q
=
S
3
=
,
.
These representations give a good account of the screening effect. The central
segment manifests itself due to current penetrating through the shielding layer
2
.
The conductive penetrability of the layer
2
is characterized by the generalized
galvanic parameters
g
and
g
, which define the generalized adjustment distances
d
and
d
.
d
and the half-width
v
The most indicative is the relation between
of
central segment. According to (7.90),
