• 한국초지조사료학회지
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• 제19권1호
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• pp.17-22
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• 1999

본(本) 시험(試驗)에서는 젖소액비의 시용수준(施用水準)이 담근먹이 옥수수의 생육(生育), 수량(收量), 토양변화(土壤變化) 및 토양중(土壤中) 침출수(浸出水) 변화(變化)에 미치는 영향을 구명(究明)코자 1996년 3월부터 1997년 11월까지 2년동안 축산기술연구소 사료작물 포장에서 수행(遂行)되었다. 간장 및 조단백질 함량은 액비(液肥) 150%구에서 각각 264cm, 6.8%로 가장 높았지만, 건물수량(乾物收量)과 TDN 수량(收量)은 화학비료구(化學肥料區)(T1)가 각각(各各) 14.5톤/ha, 9.5톤/ha로 가장 높았는데 액비로 시용할 경우, 액비 100%구(100톤/ha)가 각각(各各) 14.0톤/ha, 9.1톤/ha으로 T1구의 96% 및 97% 수준(水準)이었다. 토양산도(土壤酸度)는 시험전(試驗前) 토양에서 보다 시험 후 액상분뇨(液狀糞尿) 시용구(施用區) 토양에서 낮게 나타났다. 토양의 유기물(有機物) 함량과 인산 함량은 시험전(試驗前)에 비하여 시험(試驗) 후(後)에 액상분뇨처리구에서 높게 나타났지만 시용량(施用量)을 증가에 따른 비레적 증가는 나타나지 않았다. 한편 액비시용에 따른 침출수 중 $NO_3-N$ 함량은 전기간(全期間)에 걸쳐서 가축의 음용허용치(飮用許容値)보다 낮게 나타났다. 이상의 연구결과를 종합할 때 젖소액비의 적정시용량은 질소 함량 기준으로 200kg/ha(액비 100톤)시용이 적합하였다.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2000년도 춘계학술강연 및 발표대회 강연 및 발표논문 초록집
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• pp.9-10
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• 2000

An important business-field of world-wide steel-industry is the coating of thin metal-sheets with zinc, zinc-aluminum and aluminum based materials. These products mostly go into automotive industry. in particular for the car-body. into building and construction industry as well as household appliances. Due to mass-production, the processing is done in large continuously operating plants where the mostly cold-rolled metal-strip as the substrate is handled in coils up to 40 tons unwind before and rolled up again after passing the processing plant which includes cleaning, annealing, hot-dip galvanizing / aluminizing and chemical treatment. In the liquid Zn, Zn-AI, AI-Zn and AI-Si bathes a combined action of corrosion and wear under high temperature and high stress onto the transfer components (rolls) accounts for major economic losses. Most critical here are the bearing systems of these rolls operating in the liquid system. Rolls in liquid system can not be avoided as they are needed to transfer the steel-strip into and out of the crucible. Since several years, ceramic roller bearings are tested here [1.2], however, in particular due to uncontrollable Slag-impurities within the hot bath [3], slide bearings are still expected to be of a higher potential [4]. The today's state of the art is the application of slide bearings based on Stellite\ulcorneragainst Stellite which is in general a 50-60 wt% Co-matrix with incorporated Cr- and W-carbides and other composites. Indeed Stellite is used as the bearing-material as of it's chemical properties (does not go into solution), the physical properties in particular with poor lubricating properties are not satisfying at all. To increase the Sliding behavior in the bearing system, about 0.15-0.2 wt% of lead has been added into the hot-bath in the past. Due to environmental regulations. this had to be reduced dramatically_ This together with the heavily increasing production rates expressed by increased velocity of the substrate-steel-band up to 200 m/min and increased tractate power up to 10 tons in modern plants. leads to life times of the bearings of a few up to several days only. To improve this situation. the Mechanical Alloying (MA) TeChnique [5.6.7.8] is used to prOduce advanced Stellite-based bearing materials. A lubricating phase is introduced into Stellite-powder-material by MA, the composite-powder-particles are coated by High Energy Milling (HEM) in order to produce bearing-bushes of approximately 12 kg by Sintering, Liquid Phase Sintering (LPS) and Hot Isostatic Pressing (HIP). The chemical and physical behavior of samples as well as the bearing systems in the hot galvanizing / aluminizing plant are discussed. DependenCies like lubricant material and composite, LPS-binder and composite, particle shape and PM-route with respect to achievable density. (temperature--) shock-reSistibility and corrosive-wear behavior will be described. The materials are characterized by particle size analysis (laser diffraction), scanning electron microscopy and X-ray diffraction. corrosive-wear behavior is determined using a special cylinder-in-bush apparatus (CIBA) as well as field-test in real production condition. Part I of this work describes the initial testing phase where different sample materials are produced, characterized, consolidated and tested in the CIBA under a common AI-Zn-system. The results are discussed and the material-system for the large components to be produced for the field test in real production condition is decided. Outlook: Part II of this work will describe the field test in a hot-dip-galvanizing/aluminizing plant of the mechanically alloyed bearing bushes under aluminum-rich liquid metal. Alter testing, the bushes will be characterized and obtained results with respect to wear. expected lifetime, surface roughness and infiltration will be discussed. Part III of this project will describe a second initial testing phase where the won results of part 1+11 will be transferred to the AI-Si system. Part IV of this project will describe the field test in a hot-dip-aluminizing plant of the mechanically alloyed bearing bushes under aluminum liquid metal. After testing. the bushes will be characterized and obtained results with respect to wear. expected lifetime, surface roughness and infiltration will be discussed.

• 대한금속재료학회지
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• 제48권6호
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• pp.477-488
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• 2010

Zr-based amorphous alloy matrix composites reinforced with stainless steel (STS) and tantalum continuous fibers were fabricated without pores or defects by a liquid pressing process, and their quasi-static and dynamic deformation behaviors were investigated by using a universal testing machine and a Split Hopkinson pressure bar, respectively. The quasi-static compressive test results indicated that the fiberreinforced composites showed amaximum strength of about 1050~1300 MPa, and its strength maintained over 700 MPa until reaching astrain of 40%. Under dynamic loading, the maximum stresses of the composites were considerably higher than those under quasi-static loading because of the strain-rate hardening effect, whereas the fracture strains were considerably lower than those under quasi-static loading because of the decreased resistance to fracture. The STS-fiber-reinforced composite showed a greater compressive strength and ductility under dynamic loading than the tantalum-fiber-reinforced composite because of the excellent resistance to fracture of STS fibers.

• 대한금속재료학회지
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• 제48권2호
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• pp.109-115
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• 2010

In the present study, a Zr-based amorphous alloy matrix composite reinforced with tungsten porous foam was fabricated without pores or defects by liquid pressing process, and its microstructures and mechanical properties were investigated. About 69 vol.% of tungsten foam was homogeneously distributed inside the amorphous matrix, although the matrix of the composite contained a small amount of crystalline phases. The compressive test results indicate that the composite was not fractured at one time after reaching the maximum compressive strength, but showed considerable plastic strain as the compressive load was sustained by tungsten foam. The tungsten foam greatly improved the strength (2764 MPa) and ductility (39.4%) of the composite by homogeneously dispersing the stress applied to the matrix. This was because the tungsten foam and matrix were simultaneously deformed without showing anisotropic deformation due to the excellent bonding of tungsten/matrix interfaces. These findings suggest that the liquid pressing process is useful for the development of amorphous matrix composites with improved strength and ductility.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2006년 창립20주년기념 정기학술대회 및 국제워크샵
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• pp.21-24
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• 2006

Based on the improvement in reinforcing SiC fibers and the utilization of very fine nano-SiC powders, the well known liquid phase sintering (LPS) process was drastically improved to become a new process called the Nano Infiltration and Transient Eutectic Phase (NITE) Process. Laboratory scale NITE-SiC/SiC composites demonstrated excellent mechanical properties, thermal conductivity, hermeticity and microstructure stability which made them attractive for not only energy application but many other industrial applications. For the real deployments of these materials, mass production system and evaluation methods, together with the design code and safety assurance systems are essential. The current efforts to establish these bases were introduced.

• 한국세라믹학회지
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• 제32권7호
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• pp.825-831
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• 1995

Reaction-bonded SiC-Si material was fabricated by infiltration of Si melt into a mixture of $\alpha$-SiC and carbon at 175$0^{\circ}C$ under the vacuum atmosphere. Wear properties were analyzed by ball-on-plate wear tester, changing loading weight, sliding speed, sliding time and atmosphere, Results showed that the friction coefficient was decreased with increasing load and sliding velocity. The lowest friction coefficient of 0.05 was obtained under an oil atmosphere. The analysis of the wear surface indicated that the areas wehre particles were pulled out and where free silicon particles worn out preferentially serve as liquid reservoirs to decrease the wear resistance.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.1078-1079
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• 2006

The paper presents the possibilities of obtaining new composite materials based on sintered porous ceramics with particles and fibre of $Al_2O_3$ infiltrated by aluminum alloy. The EN AC - AlSi12 alloy features the matrix material, whereas the RF50AX-301 preform, of Saffil Automotive, was used as the reinforcement. Examinations of ceramics preforms permeability were made. Metallographic examination of composite materials made on light microscope and in scanning electron microscope show that aluminum alloys fill micropores in the matrix. New composite materials show twice higher value of hardness in comparison with matrix. Results indicate that it is possible to infiltrate porous ceramic with liquid aluminum alloy to obtain new composite materials were advantageous properties of each component are connected.

• Composites Research
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• 제26권5호
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• pp.322-327
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• 2013

탄소섬유강화 SiC기지상 복합재는 우수한 산화저항성과 우수한 열충격저항성을 가진다. 그리고 이런 특성들은 탄소섬유강화복합재가 고온구조재로서 응용케하였다. 본 연구에서는 $C_f/SiC$ 복합재가 전구체 함침과 액상 함침이 동반된 열분해공정, Cyclohexene을 사용한 화학기상 경화공정을 통해 제조되었다. 최종 제조된 $C_f/SiC$ 복합재는 5회 함침을 통해 $0.43g/cm^3$ 밀도를 갖는 탄소섬유 프리폼에서 $1.76g/cm^3$의 밀도값을 나타내고 있다. 그리고 산화저항성 특성면에서 $C_f/SiC$ 복합재의 무게가 공기중 $1400^{\circ}C$에서 6시간 유지 후에 81%가 남았다. 결과적으로 Cyclohexene을 사용한 화학기상 경화공정은 효과적으로 높은 치밀화와 증가된 산화저항성을 보이고 있다.

• 대한금속재료학회지
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• 제50권9호
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• pp.697-702
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• 2012

In this study, unidirectional and plain woven carbon fiber reinforced magnesium matrix composite laminates were fabricated by the liquid pressing infiltration process, and evolutions of the microstructure and compressive strength of the composite laminates under corrosion were investigated by static immersion tests. In the case of the unidirectional composite laminate, the main microstructural damage during immersion appeared as a form of corrosion induced cracks, which were formed at both CF/Mg interfaces and the interfaces between layers. On the otherhand, wrap/fill interface cracks were mainly formed in the plain woven composite laminate, without any cracks at the CF/Mg interface. The formation of these cracks was considered to be associated with internal thermal residual stress, which was generated during cooling after the fabrication process of these materials. As a consequence of the corrosion induced cracks, the thickness of both laminates increased in directions vertical to the fibers with increasing immersion time. With increasing immersion time, the compressive strengths of both composite laminates also decreased continuously. It was found that the plain woven composite laminates have superior corrosion resistance and stability under a corrosive condition than unidirectional laminates.

• 한국초지조사료학회지
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• 제19권3호
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• pp.203-210
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• 1999

가축액비의 영양성분 중 질소(N)는 환경적인 면과 사초수량을 고려했을 때 잠재력이 가장 높다. 본 연구는 추파용 연맥에 가축액비의 N 함량을 기준으로 시용수준을 달리하여 시용했을 때 추파용 연맥(Avena saliva L.)의 무기물 함량 및 질산태질소 함량 그리고 토양화학성분 변화를 구명하고자 7처리(화학비료표준구 $120kg\;N\;ha^{-1}$, 우분액비구 120, 240, $360kg\;N\;ha^{-1}$ 돈분액비구 120, 240, $360kg\;N\;ha^{-1}$)를 난괴법 3반복으로 배치하여 1997년 수원에서 수행하였다. 대조구와 비교하여 추파용 연맥의 무기물 함량은 액상분뇨의 시용량이 증가됨에 따라 증가되는 경향을 보였다. 추파용 연맥의 질산태질소 함량은 $1,881-2,605mg\;kg^{-1}$의 범위를 보였으며, 금비구>우분액비 $360kg\;N\;ha^{-1}$구>돈분액비 $240kg\;N\;ha^{-1}$구 순이었다. 액상분뇨의 시용량이 증가될 수록 토양중 치환성 양이온 함량이 높아지는 경향을 보였다. 토양중 전질소 및 무기태질소량은 액상분뇨 시용량에 따라 달랐는데 그 중에서도 돈분액비 $360kg\;N\;ha^{-1}$ 구에서 가장 높았다. 토양침투수중 질산태질소 농도는 시험기간중 심한 변이를 나타내지 않았다. 이상의 결과로 볼 때 토양중 질소량은 돈분액비 $360kg\;N\;ha^{-1}$구, 돈분액비 $240kg\;N\;ha^{-1}$ 순이었다.