


 !"#!$$%&"

• 
!
"#$%&'
• ()
!
"
!*(+,-./+0(
#'1+0/+(
!
02+)34+5657
('
%'8!(09:;83<=>?'
@'?A>?#B>?A
C5
/5
#
'
n
n
dt tb
r r a
−
=
D
!
:;0/+(4E7(>??AFG$:;!(09

x Km
r n
= + Ω
%
# #
' ' '
n n
i
B Fe i cuđm i
i i
đm
S
A P t P t
S
= =
 
∆ = ∆ + ∆
 ÷
 
∑ ∑
%
%
# #
' ' ' ' R 
n n
cuđm i
B Fe i i i i
i i
đmB i
P t

9
∆
d
e
$
∆
d

W
' R 
'
'
i i
tt tt
rđm
Pl
F k
U U
ρ
=
∆
∑

#
'
G!+2Efg5(W<hZ3W<9
/(REc

-A[c


S
Z
∑
=
=
∑
W-4_B
i
k
k
S
Z
Z
∑
,j7B
,j_Y+03)B<>
bR:ZF+
( ) ( )
P P
' ' ' '
i i i i
đm
r P l x Q l
U
U
+
∆ =
∑ ∑
∆
d

*
%

( )
P
' '
i i
x
đm
x Q l
U
U
∆ =
∑
*
@

r cp x
U U U
∆ = ∆ − ∆
*
Q
9>9/(
' R 
'
'
i i
tt tt
rđm
Pl

∆
d

-c

3_ERA0
∆
d

l
∆
d

0A^3)!UEc

:[#-'R0A0
3G ?(
*
#
E
[ ]
P
P$@& P$Q Mx Km∈ ÷ Ω
*
%
9
$
xABC xABD
U U∆ ∆
P

∆ = ∆ − ∆
*
Q
9
# # @ @
R 
'
tt
rđm
Pl Pl
F
U U
ρ
+
=
∆ ∆
./
ex
U∆
*
U
!+E>gmA[>9/(R
R 
tc tt
F F≤

P P
$r x
Fc


→
n
# # # # % % % %
# # # # @ @ @ @
#
'R 
#
'R 
ABC cp
đm
ABD cp
đm
U R Q X P R Q X U
U
U R Q X P R Q X U
U
∆ = + + + ≤ ∆
∆ = + + + ≤ ∆
S
# # # # % % % %
# # # # @ @ @ @
#
'R 
#
'R 
ABC cp
đm
ABD cp
đm
U R Q X P R Q X U

đm
x Q l
U
U
∆ =
∑
*
Q

Uo
cpđm
U U
∆ = ×
*
U

r cp x
U U U
∆ = ∆ − ∆
*
&

@' ' R 
r
kđ
i i
U
j
l Cos
ρ ϕ

3;f:63
ABC
U∆
*
t
C2:6
∆
d

≤

∆
d

A0
∆
d

l
∆
d

0A0$8>A-:#-'X/69W0
5c:[/69'
3G 6$
*
#
9!W
i i i i i i
S P Q S Cos

∆ = +
∆ = +
( )
e $
x xABC xABD
U U U∆ = ∆ ∆
39>YE
xABD
U∆
:;e
*
Q

Uo
cpđm
U U
∆ = ×
*
U

r cp x
U U U
∆ = ∆ − ∆
*
&

# # @ @
@' ' R 
r
kđ

đm tt
S
F k
U j
−
=
!+E>?./^
r X/6BE:[m
r (/6s:6EA[m'
*
t
C2:6./
∆
J
$

n
# # # # % % % %
# # # # @ @ @ @
#
'R 
#
'R 
ABC cp
đm
ABD cp
đm
U R Q X P R Q X U
U
U R Q X P R Q X U

#
'R 
#
'R 
ABC cp
đm
ABD cp
đm
U R Q X P R Q X U
U
U R Q X P R Q X U
U
∆ = + + + > ∆
∆ = + + + ≤ ∆
M6CD+#,%&< N$281%&O3P"
#' EW<:ZJ*KMM
≥
%5Y+:/6#$%p"#5Y+:/6@'
%' EW/uJ*K./W:mF+
e
S

e
'
'
tt
đmB
S k
S
n k


"#$@rP$@C


e
tb
đ
S
k
S
=
G E./^(+Ww<
'
#$Q'R #
csyc tt
đmB
S k
S
n
≥
−
/5b
W
W+5:vWw<
#$Q/L^(+#$Q:W
Rr##J*K/6'
Q-R<&$5S!$3!$$5PJ
o X(:;#/%W<((-:Z'
o 8/\+d2d]/63/L'
o `(83Z^#63/L4Wx?5^(

 I59-(
Q →
:;
↑

d
 J<
↓
d+O!Y'
/#;0813;X9
• *h0
↓
A∆ →
9/(0$0|
• *h0|!h2)I($9!O!G
=3!$$:B5SJ
• ,W<=>?MM=>?MM
#đd
tđ
Z
Z
n
=
• hY!hO<=>?
0OY
đm
PR QX
U
U
+

d
%
~:y
#

#
↑
Rv0
↓

⇒
d
%
↓


#
↓
Rv0
↑

⇒
d
%

↑
z R jX= +
}
Z R jX= +
xc

•W<+)_2=>?0,/
P P
$ P'g r =
N[4)W5
@
%
% P P
@
% P % P
'/WR  '#P 'WR 
'/WR  ' '#P 'WR 
x
c
x c
U
I I x j x
Z
U U x jZ I x
α α
α α
−
= +
= +
% %
%
'
đm
P Q
A R t
U

L
Z w L C
C
α
= =
]W<