• 한국작물학회지
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• 제28권3호
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• pp.345-350
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• 1983

일정한 재배조건에서 생산된 38종의 유색 대두종실을 공시하여 종실의 화학적 조성과 Texturometer를 이용한 취반에 따른 물리적 변이를 분석 조사한 결과 다음의 경향을 알 수 있었다. 1. 대부분의 유색 대두는 황태에 대한 기존의 재래종 대두 분석결과보다 단백질과 지방의 함량이 낮고 상대적으로 탄수화물 함량이 높은 경향이었으나 종실중의 차이에 따른 종실성분의 변이는 일정하지 않았다. 2. 100립중이 25-30g인 대립군의 유색 대두종은 단백질, 지방 및 탄수화물의 함량에서 상대적으로 높은 변이계수를 나타내었다. 3. 유색 대두의 Texturometer curve에서는 Hardnes, Cohesiveness, Elasticity만 반응을 보였고, Hardness는 종실중에 의하여, 기타의 Parameter들은 종실중 자체에 의하여 달라서 동일한 특성이나 종실중 내에서도 품종에 따라 유의적 차이를 보였다. 4. Hardeness와 Elasticity는 낮은 C. V치를, Cohesiveness와 Gumminess 및 Chewiness는 40% 이상의 높은 C.V.치를 나타내었다. 5. Hardness, Elasticity, Chewiness는 상호간에 정상관을 보이는 반면 이들과 Cohesiveness, Gumminess간에는 부의 상관을 보였다. 6. Hardness와 Elasticity는 탄수화물 함량과 정상관을 단백질 함량과는 역상관을 보였으며 Cohesiveness는 이들과 정반대의 경향을 나타내었다.

• Korea-Australia Rheology Journal
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• 제16권3호
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• pp.135-140
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• 2004

Morphological and rheological properties of the poly(methyl methacrylate) (PMMA) and polystyrene (PS) blends were studied by scanning electron microscopy (SEM) and advanced rheometric expansion system (ARES). From the SEM results, the PMMA-PS blends showed dispersed morphology and the particle size of the dispersed phase was quite small (0.1~0.6 $\mu\textrm{m}$ compared with other immiscible polymer blends. Values of the interfacial tension of the PMMA-PS blend were obtained from the Choi-Schowalter and the Palierne emulsion models using the storage modulus of the PMMA and PS, and found to be 1.0 and 2.0 mN/m, respectively. The interfacial tension between the PMMA and PS was also calculated from the Flory-Huggins polymer-polymer interaction parameter ($\chi$) and found to be from 0.98 to 1.86 mN/m depending on the molecular weight and composition. Comparing the values of the interfacial tension from the Flory-Huggins polymer-polymer interaction parameter and the values measured by oscillatory rheometer, it is suggested that the interfacial tension of the PMMA-PS blend obtained from the polymer-polymer interaction parameter are in good agreement with the values obtained by rheological measurements.

• Macromolecular Research
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• 제15권4호
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• pp.291-301
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• 2007

The rheological behaviors and morphologies of polylactide (PLA) and chemically modified plasticized starch (CMPS) blends were investigated. For this study, oscillatory shear flow measurements of the PLA, CMPS and their blends were performed. A scanning electron microscope (SEM) study was also conducted on the extracted extrudates of the blends. The morphology of the blend changed in relation to the composition: sphere-shaped CMPS disperse/continuous PLA, rod-like deformed CMPS phase/continuous PLA, a co-continuous structure with bridged CMPS long rods and PLA dispersed/continuous CMPS. The composition of the phase inversion could be estimated and closely coincided from the observed morphology experimental results. The rheological behavior of the blends, from oscillatory measurements, was found to vary in relation to the composition, and reflected the morphologies of the blends. PLA showed Newtonian flow behavior, while CMPS showed strong shear thinning behavior. The relationships between the morphology and rheological properties were observed in detail.

• 한국식품과학회지
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• 제24권1호
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• pp.54-58
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• 1992

국내 시판용 옥수수 전분을 시료로 하여 그 호화액의 전분농도와 측정온도에 따른 리올로지 특성을 조사하였다. $4{\sim}9%$ 옥수수 전분 호화액의 리올로지 거동은 Herschel-Bulkley 식에 적합하였고, 항복응력을 갖는 의가소성 유체의 특성을 나타내었다. 전분농도의 증가로 의가소성은 증가하였으나 의가소성의 온도의존성은 보이지 않았고, 겉보기 점도와 항복응력은 모두 지수함수적인 농도 및 온도의존성을 나타내었다. 이들 농도 및 온도에 따른 유동특성을 해석한 결과, 옥수수 면분 호화액에서 졸-겔 전이와 같은 구조적 변화를 일으키는 농도 및 항복응력을 나타내기 시작하는 농도는 각각 $6.22{\sim}6.52%$ 및 $2.6{\sim}6.52%$이었다.

• 한국기계가공학회지
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• 제3권3호
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• pp.86-92
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• 2004

This paper describes the properties of temperature-viscosity characteristics of hydrous and anhydrous electro-rheological fluids containing starch and titanium particle in silicone oil ER effects arise from electrostatic forces between the starch particles and titanium particles dispersed to the electrically insulating silicone oil induced when electric field is applied ER fluids under electric field control have been found to provide resonable estimates of ER fluid viscosity variation characteristics. Yield shear stress of the ER fluids were measured the couette cell type rheometer as a function of electrlc fields. The outer cup is connected to positive electrode(+) and bob becomes ground(-). The electrie field is applied by high voltage DC power supply. In this experiment shear rates were increased from 0 to 200 $s^{-1}$ in 2 minutes. The ER fluid's viscosity change is very small and stable at the temperature range of $40^{\circ}C$ to $60^{\circ}C$. Therefore, applications of a new ER fluid to control systems application are suitable.

• Tribology and Lubricants
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• 제28권6호
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• pp.333-339
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• 2012

Typical magneto-rheological (MR) elastomers consist of silicon-based material. A number of studies have been carried out to evaluate the vibration and tribological characteristics of silicon-based MR e-lastomers. However, these elastomers have quite low strength, so they have low wear resistance. In this study, polyurethane-based MR elastomers with performances better than those of MR elastomers. Experiments have been conducted on different MR elastomers (Pu MR elastomer, Pu-Si MR elastomer, and Pu-wrapped-Si MR elastomer) and different predefined magnetic directions (Non-Direction, Vertical Direction, and Horizontal Directionality) to evaluate the friction and wear performance under a magnetic field. The results show that Pu-wrapped-Si MR elastomer with a horizontal predefined magnetic field has the best performance in terms of wear.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.316-322
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• 2002

This paper presents the temperature-dependent hysteresis identification of an electro-rheological (ER) fluid under various operating temperatures using the Preisach model. As a first step, polymethylaniline (PMA) particles are prepared and mixed with silicone oil to make an ER fluid. A couette type electroviscometer is then employed to obtain the field-dependent shear stress. In order to show the suitability of the Preisach model to predict a physical hysteresis phenomenon of the ER fluid, two significant properties; the minor loop property and the wiping-out property are experimentally examined under three dominant temperature conditions. Subsequently, the Preisach model fur the PMA-based ER fluid is identified using experimental first order descending (FOD) curves. The effectiveness of the identified hysteresis model is verified in the time domain by comparing the predicted field-dependent shear stress with the measured one under the both specified and unspecified temperatures. In addition, the hysteresis model proposed in this work is compared to Bingham model.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.288-291
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• 2014

MRE(Magneto-rheological Elastomer) is a material which shows reversible and various modulus in magnetic field. Comparing to conventional rubber vibration isolator, MREs are able to absorb broader frequency range of vibration. These characteristic phenomena result from the orientation of magnetic particle (i.e., chain-like formation) in rubber matrix. In this study, Silicon was used as a matrix in order to manufacture MREs. Magnetic reactive powder(MRP), having rapid magnetic reaction, was selected as a magnetic particle to give magnetic field reactive modulus. The mechanical properties of manufactured MREs were measured with the application of magnetic field. The analysis of MR effect was carried out by FFT analyzer with various induced magnetic field. As the addition of CIP and induced magnetic field intensity increased, increment of MR effect was observed.

• Fibers and Polymers
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• 제6권2호
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• pp.131-138
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• 2005

A theoretical model is proposed in order to investigate rheological behavior of bubble suspension with large deformation. Theoretical constitutive equations for dilute bubble suspensions are derived by applying a deformation theory of ellipsoidal droplet [1] to a phenomenological suspension theory [2]. The rate of deformation tensor within the bubble and the time evolution of interface tensor are predicted by applying the proposed constitutive equations, which have two free fitting parameters. The transient and steady rheological properties of dilute bubble suspensions are studied for several capillary numbers (Ca) under simple shear flow and uniaxial elongational flow fields. The retraction force of the bubble caused by the interfacial tension increases as bubbles undergo deformation. The transient and steady relative viscosity decreases as Ca increases. The normal stress difference (NSD) under the simple shear has the largest value when Ca is around 1 and the ratio Of the first NSD to the second NSD has the value of 3/4 for large Ca but 2 for small Ca. In the uniaxial elongational flow, the elongational viscosity is three times as large as the shear viscosity like the Newtonian fluid.

• 한국소음진동공학회논문집
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• 제12권8호
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• pp.648-656
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• 2002

This paper presents the identification of temperature-dependent hysteresis of an electro-rheological (ER) fluid under various operating temperatures using the Preisach model. As a first step, polymethylaniline (PMA) particles are prepared and mixed with silicone oil to make an ER fluid. A couette type electroviscometer is then employed to obtain the field-dependent shear stress. In order to show the suitability of the Preisach model to predict a physical hysteresis phenomenon of the ER fluid, two significant properties; the minor loop property and the wiping-out property are experimentally examined under three dominant temperature conditions. Subsequently, the Preisach model for the PMA-based ER fluid is identified using experimental multiple first order descending (FOD) curves. The effectiveness of the identified hysteresis model is verified in the time domain by comparing the predicted field-dependent shear stress with the measured one under the both specified and unspecified temperatures. In addition, the hysteresis model proposed in this work is compared to Bingham model.