• 대한화학회지
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• 제8권1호
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• pp.9-14
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• 1964

전해질용액의 점도가 농도의 양수임은 기지의 사실이나 전농도에 걸쳐 잘 맞는 관계식은 아직 발견되지 않았다. 표면장력 역시 이러한 관계가 있으나 완전한 식은 없으며 이들은 모두 용액내의 이온의 상태에 기인하므로 표면장력과 덤도간에도 일정한 관계가 있을 것으로 생각되는 바이다. 순수한 물질에 대한 관계식은 Silverman1)이 Batchinski식 과 MacLeod 식에서 ${\gamma}^{\frac{1}{4}}=\;A/{\eta}$ + B 식을 유도하여 실험오차 범위안에서 일치된다고 했으나 아직 $Jones^{(4)}$들이 측정한 몇가지 염을 제외하고는 거의 모든 염용액의 점도나 표면장력의 정밀한 값은 측정되지 않았음으로 우선 여기서는 몇가기 염용액의 점도를 측정하였고 또 점도계수와 농도관계를 고찰하였다.

• 한국추진공학회지
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• 제2권3호
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• pp.70-79
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• 1998

고에너지 및 무연 추진제의 바인더 중 프리폴리머로 PEG 및 PCP가 널리 사용되어왔다. 본 연구에서는 PEG 프리폴리머에 PCP0260 및 PCP1270을 혼합 사용한 경우와 PCP0260, PCP1270, PEG만을 각각 단독으로 사용한 경우에 또 가소제로는 BTTN/DEGDN, BTTN/TMETN계를 사용하여 PEG/ PCP의 함량 변화, Pl/Po의 함량 변화에 대한 점도 변화를 온도에 따라서 고찰하였고, 경화된 바인더로는 PEG/PCP의 함량 변화, Pl/Po의 함량 변화에 따라 기계적 특성, 유리전이 온도를 고찰하였다. 그 결과 PCP의 함량이 증가함에 따라 점도는 상승하나, 유리전이 온도가 낮아지므로 저온물성이 좋아지며, 기계적 특성이 우수한 장점을 지니고 있다. 또한 TMETN은 DEGDN에 비하여 유리전이 온도 및 점도의 상승을 보이는 단점을 나타내고 있다.

• 대한기계학회논문집
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• 제14권1호
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• pp.241-250
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• 1990

본 연구에서는 낙구식 점도계를 이용하여 낮은 농도의 용액을 실험할 때 종말 속도측정의 어려움을 해결하기 위하여 레이저와 특수 타이머를 설치하였으며 정확한 특성시간을 결정하기 위하여 실린더 내부의 시험유체를 교란시키지 않고, 떨어뜨린 구 를 회수하는 장치를 제작하였다. 또한 주로 rheogoniometer에 의존하던 영 전단률 점성계수를 측정하기 위하여 속이 빈 알루미늄 구(hollow aluminium ball)의 밀도를 시험 유체와 거의 같은 정도까지 변화시켜가며 종말 속도를 측정하였으며 점탄성 유체 로써 Separan AP-273의 낮은 농도인 300에서 2000wppm까지의 저농도 용액에 대한 특성 시간을 여러모델에 의하여 실험적으로 결정하고 저농도 폴리머 용액에서 퇴화로 인한 점탄성유체의 특성 변화를 분석하였다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.95-96
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• 2002

The operation of proceeding bearing in the conditions of misaligned axis of proceeding and bush leads to the load concentration on the bearing edges causing further mixed lubrication conditions, unstable operation and intensive wear of mating parts. For the design process of proceeding bearing the knowledge of static characteristics determined from the oil film pressure and temperature distribution is very important. For the 3-lobe proceeding bearing, the pressure, temperature and viscosity fields, load capacity, minimum oil film thickness, power loss, oil flow and maximum oil film temperature have been determined by iterative solution of the Reynolds', energy and viscosity equations. The paper introduces the results of theoretical investigations of static characteristics of 3-lobe proceeding bearing operating at misaligned axis of proceeding and bush. An effect of misalignment ratio, length to diameter ratio of the proceeding bearing, the lobe clearance ratio on the static characteristics was investigated. Laminar, adiabatic model of oil film for the solution of Reynolds, energy and viscosity equations was applied.

• 한국염색가공학회지
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• 제13권6호
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• pp.435-440
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• 2001

This study investigates the rheological properties of in-situ polymerized solutions of polyacrylonitrile(PAN) and acrylonitrile(AN) -itaconic acid(IA) in dimethyl sulfoxide(DMSO) in terms of temperature, concentration, and time. The complex viscosity and storage modulus of the solutions were generally increased with elapsing time, which is ascribable to the three-dimensional pseudostructures formed by strong inter- or Intra-molecular attractions through Polar -CN and -COOH groups. The three-dimensional pseudonetworks would lead to relation of the acrylic solutions in long term. This was more noticeable at higher temperature within the temperature range examined. In the case of 20% solutions one can not observe lower Newtonian flow region in the viscosity curve. Disappearance of lower Newtonian flow region is indicative of heterogeneity of the solution system. Casson Plot of the viscosity data revealed that 20% solutions of PAN and AN-IA copolymer in DMSO clearly demonstrated positive yield stress, ascertaining formation of pseudostructures in the solution systems.

• 한국염색가공학회지
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• 제13권6호
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• pp.77-77
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• 2001

This study investigates the rheological properties of in-situ polymerized solutions of polyacrylonitrile(PAN) and acrylonitrile(AN)-itaconic acid(IA) in dimethyl sulfoxide(DMSO) in terms of temperature, concentration, and time. The complex viscosity and storage modulus of the solutions were generally increased with elapsing time, which is ascribable to the three-dimensional pseudostructures formed by strong inter- or intra-molecular attractions through Polar -CN and -COOH groups. The three-dimensional pseudonetworks would lead to gelation of the acrylic solutions in long term. This was more noticeable at higher temperature within the temperature range examined. In the case of 20% solutions one can not observe lower Newtonian flow region in the viscosity curve. Disappearance of lower Newtonian flow region is indicative of heterogeneity of the solution system. Casson Plot of the viscosity data revealed that 20% solutions of PAN and AN-IA copolymer in DMSO clearly demonstrated positive yield stress, ascertaining formation of pseudostructures in the solution systems.

• 한국응용과학기술학회지
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• 제17권2호
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• pp.76-82
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• 2000

The relative reactivities of branched and linear polycarbonates were investigated by measuring unreacted chloroformate concentration. It was found that the polymerization for the branched polymer proceeded ca. 10 times faster than that for the linear polymers. The effect of catalyst on a condensation step was studied by changing the amount of TEA (triethylamine) at $t_{0}$ and $t_{60}$ with keeping constant amount of TEA. The viscosity average molecular weight for the obtained branched polycarbonates were measured and compared with those of linear polycarbonates. It was found that the viscosity molecular weights of the obtained polymers decreased nonlinearly as wt % of added oligomer increased. The solution viscosities in methylenechloride for linear and branched polycarbonate increased nonlinearly as the content of polymer increased.

• Bulletin of the Korean Chemical Society
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• 제15권5호
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• pp.399-404
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• 1994

The non-Newtonian viscosities (the specific or intrinsic viscosities) of poly(L-proline) (PLP, $M_v$=19,000 and 32,000) in various mixed-solvent systems like water-propanol and acetic acid-propanol of varying compositions were measured during the reverse mutarotation (Form II ${\rightarrow}$Form I) by the application of external pressure (up to 4.5 psi). The non-Newtonian viscosity effect was found to be larger in acetic acid-propanol system than in water-propanol system and to somewhat decrease during the reverse mutarotation at a given solvent system. The non-Newtonian viscosity behavior of PLP in aqueous salt ($CaCl_2$) solution was also studied, from which it was found that the degree of the non-Newtonian effect decreased with increasing salt concentration, and increased with increasing PLP molecular weight. These findings could be explained in terms of conformational changes of PLP in solution (like the helix-helix or helix-coil transition) involved.

• 대한수학회지
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• 제48권4호
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• pp.867-885
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• 2011

We study a class of quasilinear wave equations with strong and nonlinear viscosity. By using the perturbation method for semilinear parabolic equations, we have established the fundamental results on existence, uniqueness and continuous dependence on data of weak solutions.

• 대한수학회지
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• 제44권2호
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• pp.443-453
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• 2007

We study the equation of a membrane with strong viscosity. Based on the variational formulation corresponding to the suitable function space setting, we have proved the fundamental results on existence, uniqueness and continuous dependence on data of weak solutions.