• Transactions of Materials Processing
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• v.16 no.4 s.94
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• pp.229-233
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• 2007

The present work focuses on the prediction of birefringence in injection-molded part and its improvement by rapid mold heating. To calculate birefringence, flow-induced residual stress is computed through a fully three-dimensional injection molding analysis. Then the stress-optical law is applied from which the order of birefringence can be evaluated and visualized. The birefringence patterns are predicted for a rectangular plate with a variation of mold temperature, which shows that the amount of molecular orientation and birefringence level decreases with an increase of mold temperature. The effect of mold temperature on the order of birefringence is also studied for a thin-walled rectangular strip, and the relevant results are compared with experimental measurements. Both predicted and experimental patterns of birefringence are in agreements on the observation that the birefringence level diminishes significantly when the mold temperature is raised over the glass transition temperature.

• Journal of Microbiology
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• v.34 no.1
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• pp.49-53
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• 1996

The effects of K$^{+}$ ion on the activity of RNA splicing of T4 phage thymidylate synthase gene have been investigated. The splicing activity was stimulated within the range of 5 to 20 mM concentration of KCI. When the concentration of KCI in the splicing reaction was brought to 100 or 200 mM a small amount of the exonl-intron product (1, 4 kb) was formed with large proportion of primary RNA transcript not undergoing splicing. This observation strongly suggests that there may exist come kinds of interferences with transesterification at the first step of splicing. Overall it can be concluded that K$^{+}$ ion exhibits very unique roles in RNA splicing of tdd gene depending on its concentration.ion.

• Environmental and Resource Economics Review
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• v.9 no.4
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• pp.621-639
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• 2000

High population and economic growth leads to ever increasing demand for water resources, prompting many regional conflicts for the water. With the observation, this paper examines the allocation problem of flowing water between upstream and downstream regions, We offer a two- region model in which the downstream region pays a portion of product to the upstream region in order to induce the upstream region to share the water. Our model shows that the "side-payment" does not always work, because the ex post income of the downstream region could be lower than the income without the side-payment This happens when the externality the upstream region imposes on the downstream region is small. The paper derives the condition under which the incentive mechanism like side-payment is likely to fail (or work). The model also shows that the higher the degree of externality is, the less amount of side-payment should be. The results of the paper suggest that the incentive scheme can help the regional conflicts be solved if the externality effect generated by the water use of upstream region is big enough, which is in fact the case where the conflict is severe.

• Journal of the Korean Society of Clothing and Textiles
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• v.20 no.2
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• pp.311-322
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• 1996

To accomodate workers with efficient mobility, coveralls were redesigned, construted and evaluated. In this study, especially, image processing techniques were applied to the evaluation stage, to quantify thE ease of body movement. For the initial observation stage, car-center workers were interviewed and their movements were videotaped. By analyzing the videotape, the area of stress and strains on the work clothes were marked on the figure chert and considered for the pattern making. 4DM cut pattern were applied to the upper part of the work clothes and other alternations were made throughout the problem area. Honey comb slashes were made on the problem area of the original and newly designed coveralls. Open areas of honey comb slashes due to body movement between the original and newly designed coveralls were analyzed by image processing techniques. Other objective and subjective evaluation of newly designed coveralls was compared with the original one. Overall evaluation of functionally designed coveralls was appered to be positive and the image processing techiques were useful methology to quantify the amount of stress in this study.

• Journal of the Korean Home Economics Association
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• v.20 no.1
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• pp.47-55
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• 1982

1. Pasts containing 10, 12.5, 15, 17.5 and 20g of butter respectively with identical contents of flor(16.25g) and egg(50g) were prepared. 2. For the five batter samples described above, following tests were conducted. a) Hardness and adhesiveness determination by texturometry b) Light microscopic observation d) Sensory Test 3. Significant differences of hardness, adhesiveness, and viscosity among the five samples were not recognized; but 1% significant difference in volumns were recognized. The best swelling was observed for the 17.5g butter sample; those of 15g and 12.5g butter samples were identical, while those of 10g and 20g showed the lowest swelling. Generally, stirring at 60~7$0^{\circ}C$ gave the best homogenity The degree of emulsification influenced the swelling. Not only large but also small amount of butter gave undestirable swelling. Sensory test for the 15g butter sample also gave best result.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.4
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• pp.341-347
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• 2008

Laminated LTCC components of high integrity, fabricated by thick film process, are applied to industrial field of IT technology along with miniaturization trend of electronic devices. Dispersion states were examined by several evaluation methods with MLS-22, which is one of commercial LTCC powders, to achieve optimal dispersion as basis for stable LTCC fabrication process. Slurry viscosity, surface roughness of dip-coated slide glass, sedimentaion of slurry, and SEM observation of dried surface were utilized with respective amount change of various commercial dispersants. Among these commercial dispersants, optimal dispersion state was obtained with 0.4 wt% of BYK-111, from the results of various evaluation methods.

• Journal of the Korean Ceramic Society
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• v.36 no.12
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• pp.1390-1395
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• 1999

Zr(Y,Ce)O2 TZP ceramics were prepared by sintering compacts of 3 mol% Y2O3-TZP(3Y-TZP) powders with different amount of 12 mol% CeO2-TZP(12Ce-TZP) in air at 140$0^{\circ}C$ for 2 h. The phase changes microstructure and mechanical properties of Zr(Y. Ce)O2 TZP after hydrothermal aging(20$0^{\circ}C$ 5h) were investigated. Although an addition of 12Ce-TZP accelerated the grain growth of Zr(Y, Ce)O2 TZP it restrained the transformation of tetragonal to the monoclinic phase during aging. The degradation in mechanical properties of sintered bodies was governed by the formed monoclinic phase and chemical composition. Induced Vickers indentation crack was propagated intergranually. From SEM observation of the fracture surfaces the pull-out of individual grain was confirmed.

• Journal of the Korean Ceramic Society
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• v.36 no.11
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• pp.1198-1204
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• 1999

The effect of sintering atmosphere on the grain sizes and phase distributions in 3Y-ZrO2 and 8Y-ZrO2 was investigated O2 and N2 were used as sintering atmospheres. In the case of 3Y-ZrO2 the sintered density was higher in N2 than in O2 while in the case of 8Y-ZrO2 contrary results were obtained. The observation can be explained by the nitrogen solubility into the zirconia lattice. That is nitrogen gas can behave as a diffusive gas contrary to the behavior in other oxides depending on the amount of Y2O3. In 3Y-ZrO2 tetragonal phase was retained at room temperature irrespective of sintering atmospheres. Grain sizes of two specimens were below 2㎛ and larger in O2 thin in N2 Under a given stress the transformability of tetragonal phase into monoclinic phase was higher in O2 than N2. The results are discussed on the basis of an effect of the grain size and non-transformable ttragonal(t') phase.

• Communications for Statistical Applications and Methods
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• v.20 no.3
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• pp.217-223
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• 2013

Two influence diagnostic methods for the common mean model are proposed. First, an investigation of the influence of observations according to minor perturbations of the common mean model is made by adapting the local influence method which is based on the likelihood displacement. It is well known that the maximum likelihood estimates are in general sensitive to influential observations. Case-deletions can be a candidate for detecting influential observations. However, the maximum likelihood estimators are iteratively computed and therefore case-deletions involve an enormous amount of computations. An approximation by Newton's method to the maximum likelihood estimator obtained after a single observation was deleted can reduce much of computational burden, which will be treated in this work. A numerical example is given for illustration and it shows that the proposed diagnostic methods can be useful tools.

• Proceedings of the Korean Nuclear Society Conference
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• 2005.05a
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• pp.471-472
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• 2005

After thermal aging treatment at 693 K for 322 hours, any discernable precipitation could not be found in the $13{\sim}22$ Cr ODS steels, but showing an increase in SP-DBTT and reduction in upper shelf energy. The degree of aging embrittlement increases with Cr content such that the increases in SP-DBTT are 10, 50 and 73 K in 13, 16 and 19 Cr ODS steel, respectively. Amount of hardening also increased linearly as a function of Cr content. Based on the TEM observation, the origin of hardening must be related to the invisibly fine size of Cr-rich ${\acute{\alpha}}-phase$ (<1 nm).