• 대한기계학회논문집
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• 제6권3호
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• pp.239-246
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• 1982

The effect of the second phase morphology on the fracture ductility of dual phase steel was studied by means of tensile tests carried out room temperature. In this case the second phase morphology is characterized by two kinds; one is the MEF microstructure in which martensite encapsulated islands of ferrite, the other is the FEM microstructure in which ferrite encapsulated islands of martensite. The fracture ductility is improved by variation of the second phase morphology, but is essentially uneffected in the range of high strength ratio (4.7). Also the variation of ductility is well understood according to the difficulty of cleavage crack formation of the ferrite grain and to the brittleness of the martensitic structure.

• 한국막학회:학술대회논문집
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• 한국막학회 1996년도 춘계 총회 및 학술발표회
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• pp.55-56
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• 1996

Heterophase polymer system has been attractive for a potential applicability to gas separation membrane material. It has been known that there is a trade-off between gas permeability and its selectivity in common polymers. Therefore, the heterophase polymer can be an alternative for a gas separation membrane material because its transport properties can be readily controlled by blending of two different polymers. The transport properties of immiscible polymer blends strongly depend upon the intrinsic transport properties of corresponding polymers. Another important factor to determine the transport properties is their morphology: volume fraction, size and shape of dispersed phase. Although the effect of the volume fraction of the dispersed phase on the transport properties has been widely investigated, the size and shape effects have been paid attention very much. In an immiscible polymer blend of two polymers, its morphology is primarily controlled by its volume fraction of dispersed phase. Therefore, the effect of the size of the dispersed phase can be hardly seen. Therefore, a block copolymer has been commonly employed to control their morphology when each block is miscible with one or the other phase. In this work, gas transport properties will be measured by varying the morphology of the heterophase polymer membrane. The transport properties will be interpreted in terms of their morphology. The effect of the volume fraction of the PI phase and, in particular, its size effect will be investigated experimentally and theoretically.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 춘계학술대회논문집
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• pp.116-119
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• 1999

The effects of secondary phase morphology and carbon content on the plastic deformation of 0.2C-1.5Si-1.5mn TRIP(TRansformed Induced Plasticity) steel have been investigated at various annealing and bainitic transformation temperatures. The morphology of ferrite and secondary phases was controlled by the annealing temperature and the distribution of secondary phase was controlled by the bainitic transformation temperature. The secondary phase contributed to elongation and/or UTS depending on the ferrite morphology which determined deformation mode simple elongation or rotation of secondary phase along the tensile direction In case of the sample containing the granular type retained austenite the elongation was improved as carbon stabilized the austenite phase. If the film-shape retained austenite in acicular ferrite was dominant however UTS was enhanced as the transformed martensite was hardened by carbon.

• 폴리머
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• 제25권5호
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• pp.707-718
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• 2001

폴리프로필렌 (PP)은 낮은 밀도, 우수한 내열성, 내화학성, 가공성과 더불어 재활용이 용이한 플라스틱이다. 하지만 폴리프로필렌의 발포에 대한 연구는 그리 많지 않다. 본 연구에서는 화학적 발포제를 사용하여 발포 폴리프로필렌을 만들고자 하였다. 폴리프로필렌의 가공온도에서 유동성과 발포체의 유연성을 높이기 위해 에틸렌/옥텐 공중합체 (mPE)를 폴리프로필렌에 용융 블렌드하였다. 발포에 앞서 발포체의 발포배율과 셀구조에 미치는 상분리 거동의 영향을 알기 위해 PP/mPE 블렌드 상분리 거동을 조사하였다. PP/mPE 블렌드의 강 거동은 블렌드 조성과 mixing torque ratio, 그리고 mixing rpm에 영향을 받았다. PP 기질에 mPE가 분산상으로 존재하는 블렌드를 발포시켰을 때 높은 배율과 안정한 셀 구조를 가지는 발포체를 얻을 수 있었다.

• Korean Chemical Engineering Research
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• 제55권1호
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• pp.130-134
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• 2017

Organic aerosols dispersed in the atmosphere likely undergo phase separation. Such internally mixed particles are often described as comprising an organic phase and an aqueous phase separately. We studied the morphology of two liquid separated aerosols in the sub-microscale by using a simple thermodynamic model with Russian doll geometry. The morphology of particles can be easily predicted from the simple criteria on the surface tension and two algebraic equations (the volume constraint and Young equation). This result may give the potential explanation about the complex morphology of the organic airborne particles.

• 한국세라믹학회지
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• 제44권3호
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• pp.133-136
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• 2007

The crystal morphology of hydroxyapatite [HAp] phase in gelatin [GEL] matrices was investigated with the condition of a GEL precursor treatment in an aqueous solution of $H_{3}PO_{4}$ at $37-80^{\circ}C$. Needle-shaped nanocomposite particles were prepared through a dynamic reaction during a coprecipitation process using a phosphoric GEL solution. Various types of mineralized morphology appeared with a phosphorylated condition of the GEL solution. HAp/GEL nanocomposite slurries showed the existence of an octacalcium phosphate [OCP] phase during the process.

• 한국주조공학회지
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• 제18권4호
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• pp.357-363
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• 1998

Microstructure of A356 aluminium alloys cast in a permanent mold was investigated by optical microscope and image analyzer, with particular respect to the shape and size distribution of iron intermetallics known as ${\beta}-phase$ ($Al_5FeSi$). Morphologies of the ${\beta}-phase$ was found to change gradually with the Be:Fe ratio like these. In Be-free alloys, ${\beta}-phase$ with needlelike morphology was well developed, but script phase was appeared when the Be:Fe ratio is above 0.2:1. With the Be:Fe ratios of 0.4:1-1:1, script phase as well as Be-rich phase was also observed. In case of higher Be addition, above 1:1, Be-rich phase was observed on all regions of the specimens, and increasing of the Be:Fe ratios gradually make the Be-rich phase coarse. It was also observed that the ${\beta}-phase$ with needlelike morphology was coarsened with increase of the Fe content in Be-free alloys. However, in Be-added alloys, length and number of these ${\beta}-phases$ were considerably decreased with the increased Be:Fe ratio. It was concluded that Fe impurity element to be crystallized into needlelike intermetallics was tied up by Be addition element, and new phases were crystallized into script or Be-rich intermetallics.

• Macromolecular Research
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• 제10권2호
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• pp.60-66
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• 2002

The morphology, dynamic mechanical behavior and fracture behavior of polyetherimide (PEI)/dicyanate semi-interpenetrating polymer networks (semi-IPNs) with a morphology spectrum were analyzed. To obtain the morphology spectrum, we disported PEI particles in the procured dicyanate resin containing 300 ppm of zinc stearate catalyst. The semi-IPNs exhibited a morphology spectrum, which consisted of nodular spinodal structure, dual-phase morphology, and sea-island type morphology, in the radial direction of each dispersed PEI particle due to the concentration gradient developed by restricted dissolution and diffusion of the PEI particles during the curing process of the dicyanate resin. Analysis of the dynamic mechanical data obtained by the semi-IPNs demonstrated that the transition of the PEI-rich phase was shifted toward higher temperature as well as becoming broader because of the gradient structure. The semi-IPNs with the morphology spectrum showed improved fracture energy of 0.3 kJ/$m^2$, which was 1.4 times that of the IPNS having sea-island type morphology. It was found that the partially introduced nodular structure played a crucial role in the enhancement of the fracture resistance of the semi-IPNs.

• 한국막학회:학술대회논문집
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• 한국막학회 1998년도 춘계 총회 및 학술발표회
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• pp.53-55
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• 1998

1. INTRODUCTION : Since the knowledge of vitrification phenomena can lead to a better understanding of the mechanism of membrane formation, it is desirable to include vitrification line into the phase diagrams. While the final morphology obtained during phase inversion depends upon the kinetics as well as the thermodynamics of the phase separation, the equilibrium phase diagram and vitrification line for amorphous polymers are still a good tool for controlling the morphology and interpreting the membrane structure.

• 한국잠사곤충학회지
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• 제40권2호
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• pp.169-175
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• 1998

The morphology of silk fibroin/poly(vinyl alcohol)(PVA)blend films was investigated using optical microscopy and confocal laser scanning microscopy. The effects of blend ratio and molecular weight of silk fibroin and PVA on phase separation were studied. Macro-phase separation occurred for the silk fibroin-rich/poor region whereas micro-phase separation took place for the dispersed/continuous phase, In spite of differences in molecular weight and blend ratio, it is observed that the dispersed phase and continuous one are composed of silk fibroin and PVA component, respectively. As the molecular weight of silk fibroin and silk fibroin content in blend ratio are decreased, the compatibility of blend is increased due to the reduction of micro-phase separation.