http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
이대재,Lee, Dae-Jae 한국수산과학회 2017 한국수산과학회지 Vol.50 No.5
A multi-resonant broadband acoustic transducer with six Tonpilz elements operating at different resonant frequencies in a transducer assembly was fabricated, tested, and analyzed. A compensated transducer, modified by adding series inductance to the developed multi-resonant broadband transducer, was shown to provide improved bandwidth performance with a relatively more uniform frequency response compared with the uncompensated transducer. By controlling the series inductance, flat frequency response characteristics at two frequency bands were obtained over the range 38-52 kHz with 1.1 mH inductance and 50-60 kHz with 0.4 mH inductance. These results suggest that the operating frequency of the developed multi-resonant broadband transducer in a chirp echo sounder can be shifted to a different frequency band that is optimized according to the environment for more effective echo surveys of fishing grounds.
40-75 kHz의 주파수 범위에서 동작하는 광대역 초음파 변환기의 설계 및 개발
이대재 ( Dae Jae Lee ),곽민선 ( Min Son Kwak ),강희영 ( Hee Young Kang ) 한국수산과학회 2014 한국수산과학회지 Vol.47 No.3
The objective of this study was to design and develop a broadband ultrasonic transducer that has both wide band-width and high sensitivity to measure broadband echoes related to identifying fish species. A broadband ultrasonic transducer providing a nearly flat transmitting response band of 40.2-75.5 kHz with a - 12 dB bandwidth of 35.3 kHz was achieved by integrating 12 tonpilz transducer elements operating at different resonance frequencies. The average transmitting voltage response, receiving sensitivity, and figure of merit values in this frequency band were 168.4 dB (re I μPa/V at 1m), -196.8 dB (re 1 V /μPa), and -28.4 dB, respectively. The results suggest that bandwidth and sen-sitivity can be widened and improved by adjusting the array pattern and the structure of tonpilz transducer elements.
이대재 ( Dae Jae Lee ) 한국수산과학회 2004 한국수산과학회지 Vol.37 No.4
N/A To meet the increasing demand from various fishing fields for training of fishing equipment operators, a fishing winch simulator was designed to train maritime students in the correct and safe operation of hydraulic winches under various load conditions related to fishing operations. The aim of this study is to describe the basic dynamic characteristics of the newly developed hydraulic fishing winch simulator and particularly to analyze the mechanical responses produced on the winch operation controls. The winch simulator consists of two winch units, a computer control and data acquisition system, a control consol and other associated mechanisms. When one winch is in hauling mode, the other one will always be in loading mode. The revolution speed of the hauling winch was controlled by a proportional directional control valve, and the braking torque of the loading winch was controlled by a proportional pressure control valve. The simulation experiments indicated that the dynamic characteristics of the hauling winch followed the braking response characteristics of the loading winch. The tests also showed that the warp speed and tension linearly depend on the pressure differential across the motor of the loading winch controlled by operating the proportional pressure control valve during the hauling operation. The experience gained from various training courses showed that the fishing winch simulator was very realistic and it was valuable for training novice winch operators. The results of the winch simulation exercise were recorded and used to evaluate the training on the operation and handling of the winch system. From these test results, we concluded that the tension acting on the warp during hauling operations can successfully be simulated by controlling the pressure differential across the motor with step changes of the control input signal to the proportional pressure control valve of the loading winch.
수영만 인공어초 해역에서 소너에 의한 어군의 유영행동 추적
이대재 ( Dae Jae Lee ) 한국수산과학회 2013 한국수산과학회지 Vol.46 No.3
The movement patterns of fish aggregations swimming freely near artificial reefs on August 24, 2006, at Suyeong Man, Busan, Korea, were acoustically investigated and analyzed. Acoustic surveys were conducted using a 70kHz split-beam echo sounder, 330 kHz side-scan sonar and a 310 kHz imaging sonar. Algorithms for tracking the move-ment of fish aggregations swimming in response to artificial reefs were developed. The travel direction and the swim-ming speed for two aggregations fo fish were estimated from the trajectory orientations of echo responses recorded by the imaging sonar. The first group was floating just above the reef structure, while remaining in the midwater column, and the second group was swimming through and around artificial reefs near the seabed. The mean swimming speed was estimated to be 0.40 m/s for the midwater fish aggregation and 0.17 m/s for the bottom aggregation close to arti-ficial reefs. These results suggest that the swimming behavior of fish aggregations passing close to artificial reefs near the seabed displayed a slower moving pattern than fish floating just above the reef structure in the midwater column.
12 주파수의 48 tonpilz 진동소자를 이용한 광대역 초음파 모자이크 변환기의 대역폭 확장
이대재 ( Dae Jae Lee ) 한국수산과학회 2014 한국수산과학회지 Vol.47 No.3
This article describes the design and performance characteristics of a broadband ultrasonic mosaic transducer. We focus on the improved bandwidth in the high frequency band of a previously designed broadband ultrasonic trans-ducer (Lee et aI., 2014). The improvement in the pulse-echo bandwidth was achieved by employing twelve 2x2 ele-ment subarrays, operating at different resonance frequencies, and utilizing the mosaic array concept. We found that the -6 dB and -12 dB bandwidths of the newly developed broadband ultrasonic mosaic transducer were up to 155% and 170% of the previously designed model, with a qualjty factor of 1.71 and 1.25, respectively. The averaged TVR (transmitting voltage response), SRT (receiving sensitivity), and FOM (figure of merit) values in a nearly flat trans-mitting response band, from 45 to 105 kHz providing a -12 dB bandwith of 60 kHz, were 163.3 dB (re 1 μPa/V at 1m), -192.8 dB (re 1 V / μPa), and -30.9 dB, respectively.