This study was conducted to understand the variation characteristics of suspended solid in the Keum River Estuary. Water sampling was carried out regularly with response to the tidal cycle from September, 1986 to August, 1987. Analyzed or observed items were sea water temperature, salinity, TS, TDS, TSS, VSS, FSS. and also the relationships between wind velocity, precipitation, tidal cycle and TSS were investigated. It is found that the sea water temperature is the lowest in January(2.5℃)and the highest in August(24.4℃), and increases toward upstream in summer and vice versa in winter. Salinity is the lowest in August (13.6‰) and the highest in December(20.3‰), and the annual mean value shows 13.6‰. TS and TDS are firmly related with the variation of salinity, thus, high in spring and low in summer. The annual mean values of TSS in 199.8(65.3∼454.5)㎎/ℓ, highest in March 308.2(67.5∼792. 3)㎎/ℓ and lowest in June 36.8(10.9∼200.0)㎎/ℓ. The annual mean values of VSS is 22.0㎎/ℓ, its variation tendency is similar to that of TSS. The annual mean value of VSS /TSS ratio is 13.9(6.8∼20.2)%, which are not high level compared with those of polluted sea areas. This ratio is high in summer(24.1%) and low in autumn(13.3%), and increases toward the downstream direction. It is also revealed that TSS shows a positive correlation with the wind velocity(r=0.59), and a negative with the precipitation in the Keum River basin(r=-0.64). TSS concentration is primarily subjected to the tidal range and the freshwater discharge and also related to the resuspension of bottom sediments by the action of wind force or wind waves. The dilution rate is strongly subjected to the seasonal variation of the freshwater discharge, therefore, TSS concentration shows low in summer and high in winter. Under low discharge condition in spring, autumn and winter, TSS, VSS are high level in spring tide compared with those in neap tide : under high discharge condition in summer, these values are reversed that is, TSS is higher in neap tide than in spring tide.

For the purpose of making the detection range of fish detection system more longer and computerizing the system a parametric sound source, a timer and a digitizing circuit for the Apple II computer have been studied. The parametric sound of 5 KHz generated by passing AND gate two signals from carrier signal generator of 200KHz with modulator of 5KHz. This parametric acoustic source of 5KHz difference frequency had more higher directional resolution of 10 degrees than single frequency sound of 200KHz. Peripheral interface adaptor MC 6821 was adopted for interfacing to the Apple II personal computer. The timer consisted of six decade binary coded decimal counters (74 LS 190), and the digitizing circuit consisted of a sample and hold (LF 398) and an A/D converter(ADC 0808). The timer with 10KHz clock pulse had the measuring time from 0.1msec to 100sec. This time measuring range was satisfactory for the aim of the fish finding acoustic system.

본 김치용 도마는 현재 널리 쓰이고 있는 일반 도마를 이용하여 김치와 같이 국물이 많은 식품을 절단 할 때 국물이 유출되므로써 야기되는 오염을 최소화 할 목적으로 제작된 도마이다. 이 도마의 기능적 특징은 절단시 유출된 국물이 사방으로 흐르지 않고 일차적으로 세로 경사면을 따라 흐른 다음 이차적으로 가로 경사골을 따라 국물이 김치 그릇에 흘러 내리게 되어 있어서 김치도마의 오염 넓이가 작게됨은 물론 작업테이블 및 작업장 바닥에 오염을 발생시키지 않고, 김치 그릇에 모아 떨어지게 하는 기능성을 갖인 2차원적 흐름기능을 발휘한다. 또한 본 김치용 도마는 일반적인 평면 도마에 비하여 모양이 둥근 식품이 둥굴어 떨어짐 방지기능이 있고, 사용 후 건조 속도가 빨라 위생적이며, 또한 계량적으로 식품을 절단 할 수 있음은 물론 절단시 손을 배는 위험을 적게하는 기능성이 있다. 따라서 본 도마는 김치 문화의 세계화에서 김치의 바람직한 동반자가 될 것으로 생각된다.