Bj

J

20Hz20kHz

C1/2

5900m/s3230m/s

1

Clf

1/10

1/2

lMHzlOMHz

2

Fig.1 20mm

A

B

5900mm/sec

A

TA =40 (mm) /5900103 (mm) =6.78 (nsec)

B

T8=20/5900103 (mm) =3.39 (nsec)

Fig.2

6.78(nsec5900103(mm/sec) /2=20 (mm)

70

lOmm

Fig.3

Vol.48 (2010) No. 1

CN

EECH

a1111111E

Fig. 1

Eli

II

II

nc) nsec)

Fig. 2 AB

J,!1(10.96kg

IP67

SD

IP67

USB

i

iIP66

USBCF

A- pe

2

Cn

TOFD

Fig. 3 Fig. 4

70lOmm

mm)=210 (mm) /cos 70 (deg))

=58.48(mm)

3230m/sec

Tc=58.48 (mm) /3230103 (mm) = 18.1 (nsec)

18.1(nsec3230103 (mm/sec) /2 = 26.77

(mm)

cos 7026. 77=10 (mm)

TOFD

TimeOf Flight Diaction),PAPhasedArray)

TOFD Fig.5

PA

Fig.6

Vol.48 (2010) No. 1

~

1 ... '6.I -'

~1',M

Fig. 5 TOFD

Fig. 6 PA