간행물
수산해양기술연구 KCI 등재 Journal of the Korean Society of Fisheries and Ocean Technology 韓國漁業技術學會誌
- 발행기관 한국수산해양기술학회(구 한국어업기술학회)
- 자료유형 학술지
- 간기 계간
- ISSN 2671-9940 (Print)2671-9924 (Online)
- 수록기간 1965 ~ 2024
- 주제분류 농수해양 > 수산학 농수해양 분류의 다른 간행물
- 십진분류KDC 529DDC 639
권호리스트/논문검색
권호
16권 1호 (1980년 3월) 6건
1.
1980.03
구독 인증기관 무료, 개인회원 유료
An underwater recording system was designed to measure the sound spectra of the underwater noises produced by fishing gears in operation. Recorded were noi~es from three types of fishing gears: an anchovy set net, three anchovy boat seine net and a stern trawlnet. Acoustic analysis were made using a heterodyne analyzer, a digital frequency analyzer and a level recorder. The no;'e produced by the anchovy set net was found in the high frequency region of the onset of ambient noise spectrum with a slope of - 6 dB/octave. Here the ambient noise spectrum is higher, though similar in shape, than Knudsen spectrum, and is attributed to the breaking action of the coastal wave. Measured noise spectra during the fishing operations of the anchovy boat seine nets are attributed to the background noise of the sea in the presence of the fishing vessels. The frequency distribution of the noise was 20~5, 000 Hz in the case of two steel anchovy boat seiners, and 20-3,000 Hz in the case of the wooden anchovy boat seiner. The predominant frequency range was 250~350 Hz and maximum sound pressure level was 122 dB (re 1μPa) in the case of the steel boat and ] 17 dB in the case of the wooden boat. The noises produced by the trawl fishing gears are remarkably higher than the background noi~e in the presence of the fishing vessel. The frequency distribution of the noi~e was 20-6,300 Hz. The predominant frequency range was 100~200 Hz and maximum sound pressure level was 137 dB ( re 1μPa) . The noise spectra were not so much different from that caused by vibrations of the towing cable and the structure of the ground rope of the trawl net towed in an experimental tank.
4,800원
2.
1980.03
구독 인증기관 무료, 개인회원 유료
권현망에 쓰이고 있는 오비기.수비재료를 개량하기 위하여, 속에 PVD를 넣고 밖에 PE를 둘러서 3년으로 꼰 망멱를 개발하여, 재래의 재료와 함께 그 물리적 특성을 측정.비교한 바, 다음과 같은 장점이 있음이 확인되었다. (1) 재래식은 민물에 1주야 침지하면 4~7%의 수축이 일어나는 데 비하여, 신개발재과는 그런 수축이 일어나지 않는다. (2)비중은 재래식이 1주야 침지한 후에야 겨우 1.04~1.025여서 해수보다 무겁게 하고자 하는 목적이 달성되지 않으나, 신개발재과는 침지시키지 않아도 1.06~1.09여서 비중이 크며, 필요에 따라 더 크게 하는 것도 가능하다. (3) 유연성은 재래식과 신개발재과가 비등하다. (4) 파단강도나 탄성회복도가 재래식보다 크다. (5) 6개월간 어구로서 사용한 후에도 망목이 신장되지 않았다.
4,000원
3.
1980.03
구독 인증기관 무료, 개인회원 유료
The pure polypropylen rope has been used for the head rope, and the lead cored polypropylen rope for the ground rope in the anchovy boat seine. These ropes revealed the disadvantage that deforms the net shape due to their elongation. Te improve the disadvantage, authors developed the rope of new construction which is cored by wires and wrapped by polypropylene fibers, 20mm in diameter for the head rope and 40tnm for the ground rope. To compare the physical properties of the improved rope with the conventional ones, some factors are valued and the following results are found. 1. The improved ropes rev~al some disadvantages, such as the head rope is heavier, the ground rope lighter, and both of them are stiffer than the conventional ones, contrary to the required condition of ropes) However no special difficulties are found in practical use. 2. The improved ropes display much advantages, such as elongation is 30 percent less, breaking strength is 35 precent greater, and elastic recovery is 10 percent greater than the conventional ones. Thus, it is considered that the improved ropes are more suitable for the head rope and the ground rope of the anchouy boat seine net than the conventional ones.
3,000원
4.
1980.03
구독 인증기관 무료, 개인회원 유료
빛에 대한 어류의 행동을 조사하기 위항 돌돔 Oplegnathus fasciatus 과 복섬 Fugu niphobles 에 빛의 세기가 서로 다른 여섯가지 백색인공광원으로 광을 주어, 그에 대한 반응을 주야에 각각 조사한 결과는 다음과 같다. 1. 제한된 실험수내에서의 광에 대한 구간별분포는 두 어종이 모두 구간에 많이 모여 분포은 대체로 U자형이되었다. 2. 돌돔은 수중도가 어떤값보다 높아지거나 낮아지면 광원쪽에 더 많이 모이는 경향을 보였으며, 주야간에 비슷하였다. 복섬은 수중도가 어떤 값보다 높아지거나 낮아지면 광원에서 멀리 떨어지는 경향을 보였으며 주야간에 다소의 차이가 있었다. 3.집어솔이 최대가 되는 평균수중조도(적정조도)는 돌돔이 162.0 lux (104.3-238.1 lux)로서 주야간에 같았으며, 복섬은 주간에 16.6 lux (10.6-24.5 lux), 야간에 1.9 lux (1.2-2.9 lux)로서 주간에 더 높았다. 4. 조명시간에 따른 집어솔은 돌돔의 경우 점등후 시간이 경과함에 따라 증가하는 경향을 보였으며, 야간보다 주간에 그 변화가 심했다. 복섬은 시간이 경과함에 따라 완만하게 증가하였으며, 야간보다 주간에 그 변화가 다소 심했다.
4,000원
5.
1980.03
구독 인증기관 무료, 개인회원 유료
The purpose of the present study is to find the color induced maximum gathering rate and to observed'the trend of the - gathering rate by using two species of commercial fishes: rock bream, Oplegnathus fasciatus (Temminet et Schlegel) and 'grass puffer, Fugu niphobles (Jordan et Snyder). An experimental tank(360L×50W×55H cm) was set up in a dark room. An illumination system was attached to the two end of tank to fix horizontal light intensity by co~bination c' one light bulb(20W) and four filters (red, blue, yellow, white) and the five regulating filters in order to fix light intensity. During the experiment water depth was maintained 50 cm lever in the tank. The tank was marked into six longitudinal sections each being 60 em long to observe the distribution of fish. The fish were acclimatized in dark condition for 40 minutes prior to the main experiment. Upon turning on the light, the number of fish in each section was counted 40 times every 30 seconds, and the gathering rates ,were obtain from the average number of fish in each secion. The color induced maximum gathering rate of rock bream appeared to be red, blue yellow and white color orderly.However, that of grass puffer appeared to be blue, white, yellow and red color orderly. Trend of the gathering rate in illumination time showed the remarkable fluctuation in the rock bream and little difference at the two color light sources. However, trend of the gathering rate in illumination time showed the little fluctuation in grass puffer and much difference at the two color light sources.
4,000원
6.
1980.03
구독 인증기관 무료, 개인회원 유료
The author designed and tested the high sensitive three-phase power factor meter and relay circuit, and dealt with the circuit to detect the phase of the current and the voltage. An operational amplifier comparator circuit and two single-phase transformers are used to control and detect the phase angle between the current and the voltage. The results obtained are as follows: 1. Converting the sine wave input current into the constant amplitude rectangular wave form by using a transistor chopper circuit, the power factor can be measured precisely over the load current of 0.08 A. 2. Using the moving coil type current meter, the power factor meter can be read in uniform . scale all over the range. 3. Using the three-phase power factor meter, the power factor relay which works at any power factor can be made.
4,000원
