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보문 오십천의 (五十川) 수서곤충군집에 (水棲昆蟲群集) 관한 연구
정동수,김동상,윤일병,변종욱 ( Dong Soo Jung,Dong Sang Kim,Il Byong Yoon,Jong Uk Byun ) 한국하천호수학회 1983 생태와 환경 Vol.16 No.1·2
The present study has been made on the aquatic insect community in the Osib River during the period from May 9 to July 11 in 1982. The results are as followss; 1. The aquatic insects in the Osib River are composed of total 85 species, 55 genera, 29 families in 9 orders. 2. The numbers of species according to order are listed in order of abundance as follows: Ephemeroptera: 34 species, 15 genera in 8 families Trichoptera: 18 species, 14 genera in 7 families Diptera: 18 species, 12 genera in 4 families Coleoptera: 5 species, 4 genera in 3 families Plecoptera: 5 species, 5 genera in 2 families Hemiptera: 2 species, 2 genera in 2 families Odonata: 1 species, 1 genus in 1 family Megaloptera: 1 species, 1 genus in 1 family Lepidoptera: 1 species, 1 genus in 1 family 3. The percentages of individual numbers/m² according to order in the Osib River are as follows: Ephemeroptera 48.1% Trichoptera 37.5% Diptera 13.2% Others 1.2% 4. The dominant species differ with stations in the upper stream, but those in the main stream are Stenopsyche marmorata. 5. The species diversity indices of each station range from 0.32 to 3.80. Those of station 4 are lowest. 6. Cheonduri(St.4) is much polluted station due to the waste water and the coal dust from coal mines and the drainage from Dogye Eup, So that the aquatic insects collected at that station are only 4 species of Diptera and the species diversity indices are very low.
정동수(Dong Soo Jung),이용범(Yong Bum Lee),강보식(Bo Sik Kang) 유공압건설기계학회 2018 드라이브·컨트롤 Vol.15 No.4
The objective of this paper is to evaluate the reliability of a volute pump and presents test results through performance and life tests. The performance and life test methods were presented by analyzing the failure modes of the volute pump. Zero failure test time was calculated to evaluate the reliability of the volute pump and then, the test was performed under accelerated conditions. The test was also carried out to check the failure modes of the field conditions. This study can be provided to improve the product reliability through failure analysis of the volute pump. And failure cause of typical failure case has been investigated and improvement design has been presented. The performance test results of before and after the accelerated life test were presented to confirm the improved reliability of the volute pump.
정동수(Dong-Soo Jung),김형의(Hyoung-Eui Kim),차재옥(Jae-Ock Cha) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5
When hydraulic system reaches setting pressure, piston pump including pressure compensation valve has an advantage that it reduces damage and heat of hydraulic system and it also saves energy by adjusting discharge flow to be under setting pressure. Generally, piston pump is not able to maintain constantly setting pressure needed in hydraulic system as internal pressure of piston pump delivered to pressure compensation valve is variable in accordance with discharge flow. In order to solve this, this study suggests pilot line method that delivers pressure of hydraulic system to pressure compensation valve directly and confirms improvement of pressure compensation performance through test for discharge flow and setting pressure.
정동수(Dong Soo Jung) 한국신뢰성학회 2014 신뢰성응용연구 Vol.14 No.4
Since permanent magnet coupling transfers power by magnetic force without contact, it has little shock, vibration, noise. In case of overload, it protects a pump or a motor which is relatively important by slipping internally. In this study, failure analysis and test evaluation on the permanent magnet coupling have been proposed and the process that reliability of the product improves through design improvement has been presented. And failure cause of typical failure case has been investigated and improvement plan has been presented. Finally, reliability improvement is established by analysis of the test results of before and after acceleration test.
정동수(Dong Soo Jung),강이석(E-Sok Kang) 한국동력기계공학회 2006 한국동력기계공학회 학술대회 논문집 Vol.- No.-
Electro-hydraulic type pump is used a lot in the field of industrial equipment which requires one of the control functions among pressure, flow, and power but until now, it is not applied to excavators which are exposed to severe working environment and require various control functions. In this study, for the application of electro-hydraulic type tandem pump, we present flow controller, pressure controller, and power controller by using EPPRV(electronic proportional pressure reducing valve) of which reliability is high and price is low and propose multi function algorithm and switch mode which are needed for multi function control. Lastly, we compare the experiment results between electro-hydraulic type tandem pump and hydro-mechanical type tandem pump for 5 control functions which are required on excavator, verify the validity of multi function control, and identify the improvement of performance.