文档介绍：武汉科技大学
2009 年硕士研究生入学考试试题答案及评分标准
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& ' ( ' ( )) * *
& &
' ' ( ( ) ) * *
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$ $
"" # #
" " # #
k c
1 k2
& &
−= −= ,
k1(xi x) c(x xo ) k2 xo
+
./
k x − k x k x&− k x& -
1) = 1 i 2 o ⇒ 1 i 2 o −& =
x c( xo ) k2 xo
k1 k1 xi(t) xo(t)
+ & + = & x (t)
c(k1 k2 )xo k1k2 xo ck1xi xi(t) o
,
0 /
./
&−& −= && -
c(xi xo ) kxo mxo
&&+ & + = & m
mxo xc o kxo xc i
3 7 8 @ A
4 9 : ; < = > ?
0 5 6
1 2 c
k
X o (s) = cs = cs / m
2
B
. 2
X (s) ms + cs + k 2 c k C
i s + s +
m m
k c
∴ω= 0, < ξ= < ,1 ω= ω 1−ξ 2
n m 2 mk d n
F F
F F G G
G G
E
E
E E
D HH I I
2 D 25
H H I I
D D
J K E (s) 1
1) i = (9 L )
X (s) 1+ G (s)G (s)H(s)
i 1 2
−
EN (s) G2 (s)H(s)
2) = (9 L )
+
N(s) 1 G1(s)G2 (s)H(s)
S
O P T U
N Q R
M =
3) G1(s) G10 (s /) s G10 (s) 0
1 G (s)
Θ E (s) = X (s) − 2 N(s)
1 + i +
1 G1(s)G2 (s) 1 G1(s)G2 (s)
(7 V )
s sG (s)
∴= = − 2 =
ess lim sE1(s) lim 0
s→0 s→0 + +
s G10 (s)G2 (s) s G10 (s)G2 (s)
Y
Y
Z
Y Y Z
Z Z
X
X
X X
W
[[ \ \
3 W 20
W W [ [ \ \
_ f g
] ^ ` a d e
bc
h ij
K(Ts + )1
G (s) =
k s2
l n o
m
r s t
k p q
u vw
= ⋅ 1 ⋅ 1 = 1 = 1 = =
ess lim s lim ⇒ K 10
s→0 + 3 s→0 2 + +
1 Gk (s) s s K(Ts )1 K
x z{ r
y
k
}