• 한국작물학회지
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• 제66권4호
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• pp.419-427
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• 2021

유채 봄 재배를 위한 육묘 후 기계이식 재배와 종자 직파 재배시기에 따른 생육량, 종실 수량, 그리고 종자 품질 등 차이를 구명하기 위해 수행한 결과는 다음과 같다. 1. 이식 유채와 직파 유채의 개화기 차이는 파종 시기가 늦어질수록 더 커졌으며, 2020년 2월 말 파종 방법별 개화기 차이는 12일이었으나, 4월 초 파종 시 23일이었다. 또한, 유채 개화소요 일수는 이식 및 직파 시기가 늦어질수록 짧아졌다. 2. 유채의 결실기 생육 조사 결과, 초장은 기계이식 재배에서 평균 101.6 cm로 유의성이 없으나, 직파 재배의 경우 파종 시기가 늦을수록 감소하여 유의성을 보였다. 종자 결실 비율 또한 4월 상순 기계이식 재배에서 83.6%, 3월 하순, 4월 상순 직파 유채 각각 80.4, 74.3%로 가장 낮게 나타났다. 3. 종자 수량은 2월 직파한 유채에서 275.5 kg/10a로 가장 높았으며, 4월 초 직파한 유채에서 34.6 kg/10a로 가장 낮았다. 또한, 2월 말 직파 유채에 비하여 4월 초 직파 유채의 수량은 87.4% 감소하였으며, 같은 시기 이식 유채는 31.8% 감소하여 감소폭이 적었다. 4. 유채 종자의 품질과 관련된 조지방 함량은 기계이식 재배에서는 4월 상순 이식 시 27.8%로 다른 이식 시기에 비하여 15% 감소하였으며, 나머지 3 이식시기 간의 유의성은 보이지 않았다. 직파 재배는 2월 하순에서 4월 상순까지 직파 시기가 늦어질수록 파종시기에 의존적으로 감소하는 경향을 보였다. 5. 이식 유채에서는 이식 시기와 결실 비율, 수량, 올레산 함량, 조지방 함량 간의 부의 상관관계를 보였으며, 직파 재배 또한 직파 시기와 초장, 꼬투리 생육, 결실비율, 수량, 종자 품질 간의 부의 상관관계를 보여 생육에 미치는 영향이 더 큰 것으로 판단되었다. 6. 이러한 이식 및 직파 시기에 따른 유채 생육의 변화 결과를 종합해 볼 때, 파종 시기가 늦어질수록 직파에서 받는 생육 감소 영향이 더 큰 것으로 생각된다. 본 결과는 논 안전 재배를 위한 유채 이식 및 직파 재배의 한계 파종일 및 이식일을 설정할 수 있는 자료로써, 재배법 확립의 기초 자료로 활용 될 수 있을 것으로 기대된다.

• KSTLE International Journal
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• 제6권1호
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• pp.28-32
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• 2005

The electrorheoloRical (ER) fluids are composed of a colloidal dispersion of polarizable particles in insulating oil, and it's the rheological property changes by the applied electric field. These changed are reversible and occur fast within a fewmilliseconds. The ER properties of the ER fluid such as increment of viscosity and yield stress come from the particle chain structure induced by electric fleld. When formulating the ER fluid for a speciflc application, some requirement must besatisfled, which are high yield stress under electric field, rapid response, and dispersion stability. While this characteristic makes valuable ER fluids in valious industrial applications, their lung term and quiescent application has been limited because ofproblems with particle sedimentation. In an effort to overcome sedimentation problem of ER fluids, the anhydrous ER materials of monodispersed hollow polyaniline (PANI) and adipate derivative respectively with submicron-sized suspension providing wide operating temperature range and other advantage were synthesized in a four-step procedure. The ER fluidswere characterized by FT-lR, TGA, DLS, SEM, and TEM. Stability of the suspensions was examined by an UV spectroscopy.The rheological and electrical properties of the suspension were investigated Couette-type rheometer with a high voltagegenerator, current density, and conductivity. And the behavior of ER suspensions was observed by a video camera attached toan optical microscope under 3kV/mm. The suspensions showed good ER properties, durability, and particle dispersion.

• 분석과학
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• 제5권4호
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• pp.471-475
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• 1992

유당분해효소를 유지방으로 미세캡슐화시켰으며, 이때의 미세캡슐화 수율을 정량적으로 분석하는 방법을 제시하였다. 본 연구에서 적용한 미세캡슐화 공정과정에 의한 유당분해효소의 불활성화 정도는 초기 효소활성도의 5.2%였으며 이러한 불활성화 정도를 고려하여 유당분해효소의 미세캡슐화 수율을 여러 가지 방법에 의하여 계산하였을 때 각각 92.6% (간접적인 측정방법), 88.6% (열처리에 의한 방법) 및 94.1% (효소처리에 의한 방법)였다.

• 대한기계학회논문집
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• 제18권10호
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• pp.2706-2711
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• 1994

In this work, an experimental type of torque converter has been constructed and its characteristics have been evaluated by adapting an electrorheological fluid(ERF) as an operating medium. The device was designed by using the equations which were proposed by Carlson et al. The correlation between the rheological behaviour of an ERF and mechanical parameters of the clutch has been investigated. The torque generated by an ERF in this device is sum of one due to the yield strength by polarizing dispersed particles in dielectric oil and one due to the viscous drag. The experimental results are presented in terms of torque and current density as a function of rotational speed at various electric field strength applied. Experimental results showed that the measured torque was rapidly increased with the increase of the electric field, generally being proportional to the rotational speed of the motor. The measured current was shown to be increased with the increased electric field. Also, the current was decreased with the increase of increased with the increased electric field. Also, the current was decreased with the increase of the rotational speed of the motor and reached plateau region after f = 5 Hz.

• 소음진동
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• 제9권6호
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• pp.1247-1258
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• 1999

This paper presents vibration control of a CD-ROM(compact disc-read only memory) drive feeding system consisting of a new type of CD-ROM mount using an electro-rheologocal(ER) fluid. Chemically treated starch particles and silicon oil are used for EF fluid, and its field-dependent yield stresses are experimentally distilled under both the shear and the flow modes. On the basis of the yield stress, an appropriate size of ER CD-ROM mount adapted to conventional feeding system is designed and manufactured. Vibration isolation performance of the proposed mount is evaluated in the frequency domain and compared with that of conventional rubber mount. The ER CD-ROM mount is then installed to the drive feeding system and the system equation of motion is derived. The skyhook controller is then incorporated with the fuzzy technique to improve the performance of ER CD-ROM mount. A set of fuzzy parameters and control rules are obtained from a relation between vertical displacement and pitching motion of the feedng system. Followingthe formulation of the fuzzy-skyhook controller, computer simulation is undertaken in order to evaluate vibration suppression of the CD-ROM drive feeding system subjected to various excitations.

• 소성∙가공
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• 제15권2호
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• pp.118-125
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• 2006

API steel is used for line-pipe to transport the oil and natural gas. As the recent trends in the development of API steel are towards the use of larger diameter and thicker plate, many researches have been studied to achieve higher strength, higher toughness and lower yield ratio in API steel. However, the strength of API steel after pipe forming is changed depending on the competition of the Bauschinger effect and work hardening which are affected by the strain history during pipe forming process. So, the purpose of this study is to investigate the influence of microstructure on the Bauschinger effect for API steel. To change the microstructure of API steel we have changed the hot rolling condition and the amounts of V and Cu addition. The compression-tensile test and the microstructure observation by OM and TEM were conducted to investigate the yield strength drop and the correlation between the Bauschinger effect and microstructure of API steel. The experimental results show that the increase of polygonal ferrites volume fraction increases the Baushcinger effect due to the back stress which comes from the increase of mobile dislocation density at polygonal ferrite interior during the compressive deformation. The hot rolling condition was more effective on the Bauschinger effect in API steel than the small amount of V and Cu addition.

• 통합자연과학논문집
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• 제5권2호
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• pp.79-83
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• 2012

Trialkyltin n-$Bu_3SnH$, an endocrine disruptor, was slowly converted by the catalytic action of group 4 $Cp_2MCl_2$/Red-Al (M = Ti, Zr, Hf) to produce two phases of products: one is an insoluble cross-linked solid, polystannane in 7-23% yield as minor product via redistribution/dehydrocoupling combination process, and the other is an oil, hexabutyldistannane in 69-90% yield as major product via simple dehydrocoupling process. Redistribution/dehydrocoupling process first produced a low-molecular-weight oligostannane possessing partial backbone Sn-H bonds which then underwent an extensive cross-linking reaction of backbone Sn-H bonds, leading to an insoluble polystannane. This is the first exciting example of redistribution/dehydrocoupling of a tertiary hydrostannane catalyzed by early transition metallocenes.

• 한국약용작물학회지
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• 제17권6호
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• pp.415-420
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• 2009

This study was carried out to select economical byproduct composts as the substitute for the traditional organic fertilizer, Yacto, in the cultivation of ginseng seedlings, and to investigate the application method of a selected compost. Among tested byproduct composts, popped rice hull compost was the best substitute for Yacto, while the application of domestic animal manure composts resulted in red skinned roots of ginseng seedlings. Optimal mixing ratio of the popped rice hull compost with virgin soil (fine sand) were 3~4 : 1 in bulk, showing the same root yield compared to that of conventional seedbed soil. When the popped rice hull compost was lower than $1\;{\pm}\;0.1%$ in nitrogen content, the expeller cake of oil seed was added to seedbed soil to rise nitrogen content until $1\;{\pm}\;0.1%$.

• Tribology and Lubricants
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• 제13권3호
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• pp.115-123
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• 1997

The electrorheological (ER) behavior of suspensions in silicone oil of silica gel powder (average particle size 49 $\mu$m) absorbed water was investigated at room temperature with electric fields up to 2.4 KV/mm. In this paper, for development of succcessful ER fluids used for wide temperature range later, we would like to know a fundamental understanding of water on ER effect. As a first step, the ER fluids involving water activated silica gel were measured not only the electrical characteristics such as dielectric constant, current density and electrical conductivity but also the rheological properties on the strength of electric field, the quantity of dispersed phase and absorbed water. From the experimental results that water absorbed to the particles directly affects to the surface charge density of electric double layer model proposed by Schwarz and makes dielectric constant and current density of ER fluids increase. The current density and dynamic yield stress $($\tau$_y)$ of water activated silica gel suspensions was in exponential proportion to the strength of electric field, the quantity of dispersed phase and absorbed water. And the optimum water quantity and weight concentration of silica gel for electrorheological effect were 4-5 wt% and 15 wt%, respectively.

• Journal of the Korean Wood Science and Technology
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• 제44권5호
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• pp.629-638
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• 2016

본 연구에서는 급속열분해 공정 중 팜 부산물(empty fruit bunch: EFB)에 존재하는 무기성분이 급속열분해 산물의 물리화학적 특성에 미치는 영향을 조사하였다. 팜 부산물에 존재하는 무기성분을 제거하기 위해 불산과 증류수를 사용하였으며, 팜 부산물의 회분 함량은 무기성분 제거 전 6.2 wt%에서 2.4 wt% (불산 처리: HF-EFB), 3.5 wt% (증류수 처리: DI-EFB)로 각각 감소하였다. 무기성분 정량 결과 팜 부산물에 다량 존재하고 있던 칼륨이 두 용매 모두에서 가장 높은 제거효율을 나타냈다(불산: 80.3%, 증류수: 78.3%). 무기성분이 제거된 팜 부산물은 유동형 급속열분해 장치를 이용하여(온도조건 $500^{\circ}C$, 체류시간 1.3초) 바이오오일, 바이오탄, 비응축성 가스로 변환시켰다. 바이오오일의 수율은 불산 처리 후 57.3 wt%, 증류수 처리 후 51.3 wt%로 각각 나타났다. 팜 부산물 내 무기성분 함량이 낮을수록 바이오탄의 수율은 감소하였고, 비응축성 가스의 수율은 증가하는 경향을 나타냈다. 바이오오일의 물리화학적 특성 분석결과에 의하면 수분 함량은 무기성분 제거 전 26.9%에서 불산 처리 후 9.9%로 감소한 반면 점도는 16.1 cSt에서 334 cSt로 증가하였다.