• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.476-479
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• 2002

The ageing cause in many porcelain suspension insulators which occur on transmission and distribution line with dead-end stings is mechanical stress in interface between porcelain and cement materials. It is known that the principal mechanical stress which give electrical failure is the results of the displacement is due to cement growth. We studied the effect of cement displacement resulting environmental ageing parameters on porcelain insulator mechanical properties for transmission line by simulation (ANSYS/NASTRAN program) and test methods. These simulation analysis and experimental results show that cement volume growth affects severely to be mechanical failure ageing.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.9 s.252
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• pp.1102-1109
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• 2006

In this paper, the polarization of piezoelectric materials is considered to improve actuation since the piezoelectric polarization has influences on the performance of the actuator. The topology design of compliant mechanism can be formulated as an optimization problem of material distribution in a fixed design domain and continuous approximation of material distribution (CAMD) method has demonstrated its effectiveness to prevent the numerical instabilities in topology optimization. The optimization problem is formulated to maximize the mean transduction ratio subject to the total volume constraints and solved using a sequential linear programming algorithm. The effect of CAMD and the performance improvement of actuator are confirmed through Moonie actuator and PZT suspension design.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.3
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• pp.336-343
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• 2015

One of various main jobs in the design of a new tactical vehicle is to develop the lightest chassis parts satisfying the required durability target. In this study, the analytic methods to reduce the size and weight of a lower control arm and chassis frame of a Korean light tactical vehicle are presented. Topology optimization by ATOM (Abaqus Topology Optimization Module) is applied to find the optimal design of the suspension arm with volume and displacement constraints satisfied. In case of chassis frame, the light-weight optimization process associated with design sensitivity method is developed using Isight and ABAQUS. By these analytic methods we can provide design engineers with guides to where and how much the design changes should be made.

• The Korean Journal of Food And Nutrition
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• v.6 no.4
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• pp.301-306
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• 1993

Effects of pressure and pressing time of soyprotein-CaSO4 coagulates on the yield, water holding capacity and textural characteristics of SPI (soy protein isolated) tofu were investigated. The tofu was prepared by addition of CaSO4 into SPI suspension at 9$0^{\circ}C$ and then compressed. As the compressing pressure increased from 8.66g /cm2 to 49.43g /cm2, the volume yield and moisture absorbed on filter paper were decreased and the textural properties of hardness, adhesiveness, cohesiveness and gumminess were increased. Increase in hardness and gumminess were more significant at high pressure than those at low pressure.

• Journal of the Korean Chemical Society
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• v.29 no.3
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• pp.233-238
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• 1985

The non-porous and porous polystyrene divinylbenzene copolymers were prepared by the suspension polymerization method. The non-porous aminated polystyrene divinylbenzene, N-APSTDVB and the porous aminated polystyrene divinylbenzene, P-APSTDVB of 50∼100mesh size weakly basic anion exchanger were synthesized by chloromethylation followed by amination with methylamine. The functional groups of these synthesized anion exchangers were confirmed by their infrared spectra. The maximum capacity of these exchangers was 4.86meq/g. Pore volume and pore spectra were determined with a mercury porosimeter. The pore volume of P-PSTDVB increased with increasing X$_{diluent}$ at 30% of divinylbenzene. However, the pore volume of P-PSTDVB increased with increasing volume percent of divinylbenzene at constant mole fraction of diluent, X$_{diluent}$ of 0.5. The pore volume of synthesized copolymer and anion exchanger at 8% divinylbenzene and 0.5X$_{heptane}$ decreased as follows; P-PSTDVB 〉P-APSTDVB 〉N-PSTDVB. This result was attributed to the possibility that the pore volume were reduced by amination reactions. The distribution coefficients of boric acid on the N-APSTDVB anion exchanger in various concentrations of alcohol water solutions showed that as alcohol concentration increased, the distribution coefficients values decreased due to the reduced concentration of H$_2$BO$_3^-$.

• YAKHAK HOEJI
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• v.36 no.6
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• pp.538-547
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• 1992

Optimal synthetic condition of barium sulfate were investigated from the viewpoint of yield and bulkiness according to a randomized complete block design proposed by G.E.P. Box and K.B. Wilson. Barium chloride and magnesium sulfate were utilized as reactants in order to prepare barium sulfate in this study. It was found that optimum temperature range of reactant solutions was $60{\sim}100^{\circ}C$ and the optimum concentration range of the reactant solutions was $10{\sim}17.3%$ and $10{\sim}20%$ respectively, on the viewpoint of yield and bulkiness. The optimum mole ratio of $BaCI_2$ to $BaSO_4$ was in the range of $1.50{\sim}2.0$ and the optimum mole ratio of $BaCI_2$ to $BaSO_4$ was in the range of $1.50{\sim}2.0$ and the optimum reacting time range was $15{\sim}20$ minutes. The optimum drying temperature range was $110{\sim}130^{\circ}C$ from the viewpoint of yield, but it was $90{\sim}110^{\circ}C$ on the basis of bulkiness. Apparent viscosity of barium sulfate suspensions dispersed in various concentrations of Na. CMC was measured by using Brookfield synchrolectric viscometer model LVT, the relative equation, log ${\eta}_{sp}=A+B.{\phi}$ was examined and the equation was found to agree fairly well. 1 w/v% Na. CMC aqueous solution and 0.1 volume fraction of $BaSO_4$ powder were optimum in the preparation of $BaSO_4$ suspension showing highest viscosity at infinite shearing.

• Journal of the Korean Ceramic Society
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• v.39 no.10
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• pp.981-987
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• 2002

Monodispersed colloidal silica was prepared by Stober process. We have synthesized monodispersed colloidal silica of carious sizes (100 nm, 200 nm, 300 nm) by controlling volume ratios of TEOS(Tetraethylorthosilicate), $NH_4OH$, Ethanol and D. I. water. Shape and monodispersity of the synthesized colloidal particles were observed by Scanning Electron Microscopy(SEM) and laser light scattering particle analyzer. Self-assembled monolayer of monodispersed colloids was achieved by dipping Si substrate into a well-dispersed silica suspension. It was determined that uniformity and spatial extent of the self-assemble monolayer of monodispersed colloids are significantly influenced by the experimental parameters such as concentration, pH and surface tension of the colloidal suspension. We have observed a hexagonally well-ordered packing colloidal monolayer in a relatively large area (1.5 mm ${\times}$ 1.5 mm) as confirmed by SEM.

• Korea-Australia Rheology Journal
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• v.21 no.3
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• pp.155-160
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• 2009

Micropore filtration of dilute red blood cell (RBC) suspensions is a widely known method for determining red blood cell deformability. Use of this method for cells from various laboratory animal species does require considering the effects of the cell size to pore size ratio and of suspension hematocrit. In general, previous animal studies have utilized 5% hematocrit suspensions and five micron pores, and thus conditions similar to human clinical laboratory practice. However, when used for repeated sampling from small laboratory animals or for parallel multiple samples from different sites in large laboratory animals, the volume of blood sampled and hence the hematocrit of the test suspension may be limited. Our results indicate that hematocrit levels yielding stable values of RBC pore transit time are pore size and species specific: three micron pores = $2{\sim}5%$ for dog and $3{\sim}5%$ for rat; five micron pores $3{\sim}5%$ for dog and $1{\sim}5%$ for rat. An analytical approach using a common expression for calculating transit time is useful for determining the sensitivity of this time to hematocrit alterations and hence to indicate hematocrit levels that may be problematic.

• Journal of Korean Society on Water Environment
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• v.35 no.3
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• pp.201-208
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• 2019

In this study, we analyzed composition of the bioflocculant, which strain YG-02 produces. First, supernatant and suspension from centrifugation of culture fluid of the strain, were used in the flocculation experiment. As a result, the SVI(sludge volume index) added with the suspension, was 182 mL/g, same as the control group with no additive, and the SVI added with supernatant, was 164 mL/g. So, the result above showed that flocculation capacity of the bioflocculant, was dependent on the substance which strain YG-02 produces, not on factors such as the body of germs. As a result of the thermostability test on substances that cause flocculation, the flocculation effect was significantly reduced, compared to the result of the flocculation test, before applying heat to the culture fluid, and it was able to assume that the substance that causes flocculation, was damaged by heat. Additionally, to understand the component of the bioflocculant, analyzation of sugar composition and fatty acid, was conducted. As a result, sugar composition was the polysaccharide consisting of glucose: lactose with molar ratio of 90.75:9.25. Fatty acid content was detected, as 0.0012 g/100g, showing that it contained glycolipid in the bioflocculant. Such results show that the bioflocculant which strain YG-02 produces, is the new bioflocculant, different from bioflocculantstudiedto date.

• Journal of the Korean Society of Radiology
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• v.84 no.2
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• pp.441-453
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• 2023

Purpose To evaluate the development, location, and volume of a VX2 carcinoma using four inoculation methods in a rabbit brain. Materials and Methods Inoculation of a VX2 cell suspension was performed 1) on the appointed day, 2) seven days after storing a VX2 carcinoma in a freezer or 3) seven days after storing a VX2 carcinoma in a deep freezer after sacrificing the donor rabbits. 4) Without sacrificing the rabbits, the VX2 cell suspension was obtained using a gun biopsy, inoculation was performed on the appointed day. MR imaging was performed 10 days after inoculation. Brain tissues were obtained the day after. The development, location, and volume of the tumor were evaluated. Results Seventeen of the 18 rabbits inoculated on the appointed day developed tumors (average tumor volume, 106.32 mm³). One of five inoculated seven days after storing the VX2 tumor in the freezer, and three of five inoculated seven days after storing the VX2 tumor in the deep freezer developed tumors. Inoculation with a VX2 cell suspension obtained with a gun biopsy from five rabbits revealed development of tumors in only two rabbits. The tumors mostly developed in the superficial cortex. Conclusion TVX2 rabbit brain tumor model is easy to develop and revealed variable reproducibility. This model can be applicable in radiologic imaging, treatment planning, interventional treatment and drug delivery research. VX2 cell can be successfully innoculated into the brain using variable methods under researcher's variable conditions.