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오스템퍼링 처리한 C/V 흑연 주철의 마모에 미치는 잔류 오스테나이트량의 영향에 관한 연구
주도재,김홍범,천병욱,최창옥 ( Do Jae Joo,Hong Beom Kim,Byung Wook Cheon,Chang Ock Choi ) 한국주조공학회 1998 한국주조공학회지 Vol.18 No.4
N/A C/V graphite iron has superior tensile strength, toughness and ductility than grey iron, and better castability than ductile iron. The retained austenite content of C/V graphite iron by austempering treatment affects on the mechanical properties such as ductility, hardness, wear properties and machinability. C/V graphite iron alloyed with Cu and Mo were carried out on the austenitizing at 900˚C for 1 hour, and the austempering at 240∼400˚C for 1 hr. And then the mechanical and wear properties of austempered C/V graphite iron have been investigated by the retained austenite content. In consequence, the retained austenite content was found to be 18.2% in austempering temperature at 240˚C, and was increased 39.2% at 400˚C. Tensile strength and hardness of austempered C/V graphite iron were decreased as the retained austenite content increased, but elongation was increased. The rolling wear loss were increased as the retained austenite content increased. The wear surface of as-cast became to be rough. The microstructure of austempered C/V graphite iron was became to be acicular ausferrite in austempering at 240˚C, and feathery ausferrite at 400˚C. (Received December 31, 1997)
오스템퍼드 구상흑연주철의 마멸 특성에 미치는 잔류 오스테나이트의 영향에 관한 연구
김홍범,주도재,최창옥 ( Hong Beom Kim,Do Jae Joo,Chang Ock Choi ) 한국주조공학회 1996 한국주조공학회지 Vol.16 No.6
N/A Austempered ductile irons(ADI) are characterized by their relatively high retained austenite content which has a significant effect on mechanical properties and performance, such as ductility, toughness, wear resistance and machinability. Austenitising treatment at 900℃ for 1∼2hours, and austempering treatment within the temperature range 240∼400℃ on ductile cast iron alloyed with Cu and Mo were carried out, and the effects of retained austenite content on the mechanical properties and wear resistance were investigated. In consequence, the amount of retained austenite was found to be 13.5% at the austempering temperature of 240℃, and was increased 28% at 400℃. Tensile strength and hardness of austempered ductile iron were decreased as the retained austenite content increased, but elongation was increased. The retained austenite content at the austenitising time of 2hours was more than at l hour. The amounts of rolling wear loss were increased as the retained austenite content increased, and the wear surface was become to be rough.
The Effect of Wood Extract as a Water-Soluble Fertilizer in the Growth of Lactuca sativa
( Ji Young JUNG ),( Si Young HA ),( Jae-Kyung YANG ) 한국목재공학회 2021 목재공학 Vol.49 No.4
Recently, due to environmental and toxicity issues, there has been increasing attention on research regarding natural products that can reduce the use of chemical fertilizers. Wood extracts derived from the biorefining process contain various fertilizer ingredients. HPLC analysis revealed that wood extract contains approximately 5.2% hemicellulosic sugar. The growth of lettuce (Lactuca sativa) upon treatment with wood extract (extract obtained from steam-exploded pine) or water-soluble fertilizers containing different nutrients was analyzed in this study. After two weeks, the growth characteristics of lettuce as affected by wood extract or water-soluble fertilizers were significantly different. The effect of water-soluble fertilizers containing ascorbic acid, magnesium sulfate, citric acid, potassium nitrate, amino acids, or seaweed extract was less desirable than that of wood extracts regarding plant height (18.6 cm), number of leaves (10), leaf length (14.1 cm), shoot fresh wight (9.8 g/plant), root fresh weight (0.8 g/plant) and shoot dry weight (0.6 g/plant). The plant height, number of leaves, leaf length, shoot fresh wight, root fresh weight, shoot dry weight of water-soluble fertilizers containing wood extract were significantly different compared to the control (plant height :13.5 cm, number of leaves : 7, leaf length : 9.4 cm, shoot fresh wight : 5.3 g/plant, root fresh weight : 0.7 g/plant, shoot dry weight : 0.4 g/plant, root dry weight : 0.07 g/plant). From these results, it was concluded that wood extract can be used as a potential water-soluble fertilizer to increase the yield of leafy vegetables.
전기차 에어컨용 평형 베인 압축기의 성능 특성에 관한 연구
이준용(Junyong Lee),허형석(Hyungseok Heo),배석정(Sukjung Bae),주도재(Dojae Joo) 한국자동차공학회 2017 한국자동차공학회 학술대회 및 전시회 Vol.2017 No.11
In the automobile industry, interested in carbon free electric vehicles because the limited supply of fossil fuel and environmental problems caused by exhaust gases. Recently, as international exhaust emission regulations are strengthened, not only research on electric vehicles is actively conducted, but also conventional mechanical type automotive parts are being electrified. Research on reducing the power consumption by improving the cooling system parts has been promoted by directly affecting the fuel consumption of automotive cooling systems. There is no case of applying a vane compressor to automobiles that are produced domestically. In overseas, researches for improving the efficiency of a cooling system to which a vane compressor is applied have been actively promoted in order to improve the fuel efficiency of electric vehicles. The purpose of this research is to compare and analyze the performance characteristics of scroll type air conditioner compressor and balanced vane compressor of electric vehicle and experiments were conducted to confirm the performance characteristics of the balanced vane compressor.
전기차 에어컨용 베인 압축기의 열유동 해석을 통한 성능 설계
배석정(Sukjung Bae),허형석(Hyungseok Heo),이준용(Junyong Lee),전찬대(Chandae Jeon),주도재(Dojae Joo) 한국자동차공학회 2015 한국자동차공학회 학술대회 및 전시회 Vol.2015 No.11
The air conditioning system for cooling an electric vehicle is driven by a high-voltage electric compressor since there is no engine power, while the conventional internal combustion engine vehicles use engine powered compressor. When the air conditioning system - or the heat pump system for heating the cabin room at winter season in recent application in the electric vehicle - is activated, the mileage per charge is significantly reduced by about 25 ~ 30%. And the cost reduction is emphasized on expensive components and systems for the electric vehicles. Therefore, reduction of power consumption and cost savings is required in the development of high-voltage electric compressor for the electric vehicle air conditioning system. Rotary vane type compressor is proper for realizing these conditions. This study has been carried out through the design of the vane compressor for an electric vehicle air conditioning system by method of unsteady state, compressible thermal flow analysis. The effect of the geometries of suction and discharge sections on the rotor core, the ratio of speeds at suction and discharge sections, and side clearance have been investigated on the performance of the vane compressor. An appropriate model through this design process has been selected and its compression performance data such as discharge flow rate, hydraulic torque, power consumption, volumetric efficiency, etc. have been predicted.