• Biomedical Science Letters
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• v.10 no.3
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• pp.259-262
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• 2004

The aim of present study was to examine the effect of carrageenan on the tendon of skeletal muscle of rat. The tendon damage was induced by injection of carrageenan into skeletal hind muscle of rats. Rats were killed on 48 hours after carrageenan injection. The resulting tendons were fixed with 10％ neutral buffered formalin (NBF), dehydrated, embedded, sectioned by 4 μm, and stained by phosphotungstic acid hematoxylin (PTAH) or hematoxylin-eosin (H-E). Carrageenan induced the segregation of tendon fibers, intratendinous cleft, segregation of muscle cell group, wave arrangement of tendon fiber. The results suggest that carrageenan induced tendon damage of rat's skeletal muscle by morphological changes.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.8
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• pp.966-971
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• 1988

AES was used to study oxygen adsorption due to the oxygen exposure at 300\ulcorner temperature and segregation of impurities due to annealing on polycrystal copper surface. The intensity of peak of CuM2, 3VV and CuL3 VV increased with annealing time and the peak of CKLL increased after Ar ion bombardment. The effect of oxygen adsorption on copper surface at 300\ulcorner was verified by the decreased of peak of CuM2, 3VV and CuL3 VV as oxygen exposure increase. The binding energy of copper atoms gradualy shifts from 0.7eV to 1.5eV of copper atoms gradually shifts from 0.7eV to 1.5eV after a oxygen exposure. After the oxygen exposure, the width at half the height of CuM2, 3VV is larger 2V*C/S by the effect of chemical liaison of the copper aton with oxygen atom.

• Journal of the Korean Ceramic Society
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• v.29 no.1
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• pp.1-8
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• 1992

The effect of CaO impurity on the microstructural evolution during the sintering of ultrapure alumina(>99.999%) was studied under "clean" firing conditions. The sinterability of undoped alumina was low, but its microstructure was maintained uniform. In the case of CaO-doped alumina, the distribution of grain size and that of grain boundary dihedral angle became wider, and facetted pores observed frequently. When MgO was doped in addition to CaO, the sinterability increased drastically and the uniform microstructural characteristics resumed. This study suggests that the effect of CaO is to induce inhomogeneous microstructures presumably by anisotropic segregation to grain boundaries and pore surfaces, and that MgO suppresses the anisotropic segregation of Ca.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.10a
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• pp.152-155
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• 2004

In the semi-solid die casting process, the important thing is the flow behaviors of semi-solid material. The flow patterns of semi-solid material can make the defects during die filling. To control of the flow patterns, is very important and difficult. In this paper, the flow behaviors of the semi-solid A356 alloy material during die filling at various die gate shapes has been observed with the grain size controlled material. The effects of the gate shape on the die filling characteristics were investigated. The filling tests in each plunger strokes were experimented, also simulated on the semi-solid material die casting process by MAGMAsofi. According to the filling tests and computer simulation, the effect of the gate shape on liquid segregation had been investigated.

• Proceedings of the Materials Research Society of Korea Conference
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• 1998.11a
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• pp.132-132
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• 1998

• Journal of Korea Foundry Society
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• v.27 no.6
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• pp.243-249
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• 2007

The effect of Re addition and solidification rate on the directional solidification behavior of Ni-Al model alloy has been investigated. Directional solidification (DS) were carried out using the modified Bridgman furnace with various solidification rates. The solid/liquid interface during directional solidification was preserved by quenching the specimen after the desired volume fraction of original liquid was solidified. The equilibrium partition coefficients of Al and Re Were estimated by measuring the compositions at the quenched solid/liquid interface. Then, the effect of Re addition on the elemental segregation behavior was carefully analyzed. The differential scanning calorimetry results showed that the Re addition results in increased ${\gamma}'$ solvus and freezing range of the alloy. It was also shown that the primary dendrite arm spacing gradually decreases with increasing the Re content, while the secondary dendrite arm spacing appears to be independent on the Re content. The compositional analyses clearly revealed that the segregation of Al increased with increasing the Re content and solidification rate, while that of Re was found to be independent on the solidification rate in the range of $10{\sim}100{\mu}m/s$ due to its sluggish diffusion rate in the Ni solid solution.

• Korean Journal of Materials Research
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• v.9 no.9
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• pp.883-889
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• 1999

The pure Al or-(1,2,3wt%)Cu alloy internal chill with 4,6,8,12 and 15mm ø, respectively, was inserted at the center of a graphite mold with the size of 95mm ø$\times$200mm H. The molten metal with the same composition as the internal chill was poured into the mold at the pouring temperature of $750^{\circ}C$ and the cooling rates, solidified structures and chemical segregation were analyzed. The results represented that there was remarkable increased in cooling rate as well as decrease in grain size, secondary dendrite arm spacing and chemical segregation as the ratio of ingot to internal chill diameter was increased to 8. However there was a considerable drop of the internal chill effect when this ratio exceeded 8, resulting from incomplete melting of internal chills. The optimum ratio for the maximum internal chill effect of pure Al and-(1,2,3wt%)Cu allolys was 8 at the given pouring temperature.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2002.11a
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• pp.99-102
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• 2002

This paper discusses the estimation of construction cost of high fluidity concrete using segregation reducing type superplasicizer with 350kgf/cm2 of design strength and 60$\pm$5cm of slump flow in order to verify the cost down effect of high fluidity concrete compared with that of plain concrete with 350kgf/cm2 of design strength and 18cm of slump and with 210kgf/cm2 of design strength and 15cm of slump. According to research, under same strength levels, although material cost of high fluidity concrete is somewhat higher than that of plain concrete due to segregation reducing type superplasticizer, labor cost and equipment cost of high fluidity concrete is cheaper than that of plain concrete. However, based on the strength differences, high fluidity concrete shows lower material cost, labor cost and equipment cost than that of plain concrete due to decreasing in size of member and re-bar caused by high strength development of concrete.

• Journal of Korea Foundry Society
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• v.25 no.6
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• pp.240-248
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• 2005

The rheocasting characteristics are strongly influenced by the microstructural morphology such as particle size, form factor and contiguity. In this study, the effect of structural morphology on fluid flow characteristics of A356 semi-solid alloy was investigated with a vacuum suction fluidity test. Semi-solid metal slurry was made by the mechanical stirring, the liquidus casting, and H-NCM to be analysed. H-NCM could obtain uniform and fine globular microstructures of 0.9 form factor and 55 ${\mu}m$ particle size. Inoculation was found to be effective for reducing particle size, however, for H-NCM it should be avoided due to the cause of increasing contiguity. The fluidity test indicated that the non-stirring method had higher fluidity and smaller liquid segregation in the same solid faction of 0.4 than the stirring method, for smaller particle size and higher form factor. It was observed that liquid segregation decreased as the particle size is smaller and form factor is higher. The results of die-casting experiment were a good agreement with those of fluidity test.

• Journal of the Korean Geotechnical Society
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• v.26 no.4
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• pp.5-14
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• 2010

Three years of frost heave field experiments were conducted to evaluate a method for reducing heave using a recycled tire powder-soil mixture. By mixing Tomakomai soil with 20% recycled tire powder, frost heave amount was drastically decreased. The results of the field experiment confirm that recycled tire powder is an excellent material for use in controlling the total amount of heave. The restraining effect of a recycled tire powder-soil mixture is qualitatively analyzed based on amount of frost heave, frost heave ratio, thermal conductivity, permeability and segregation potential theory.