• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.5
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• pp.405-411
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• 2012

Inside a rotorcraft fuel cell, pipes and components are located for fuel storage and fuel supply into the engine. Utility helicopters, operated in battle fields, fly at lower altitude compared to fixed-wing aircraft and hence are more likely to be exposed to gunfire. Since internal pressure of fluid increases when hit, the effect on LRU due to increase in pressure must taken into account when designing the aircraft for survivability. However, it is costly and time consuming to manufacture a fuel cell for gunfire test, and due to constraints from usage of live ammunition, related data gathered through numerical simulation is needed. In this study, numerical simulation on rotorcraft fuel cell exposed to gunfire was carried out using Autodyn to analyze bullet movement inside the fuel cell after hit, and internal pressure of fluid and equivalent stress on fuel cell assessed.

• Proceedings of the SCSK Conference
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• 2003.09a
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• pp.700-718
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• 2003

Fructan, a polysaccharide existing in plants or produced by microorganisms, is a sugar polymer of fructose with $\beta$-2,6 linkages. In this study, we investigated some cosmeceutical properties of Fructan such as moisturizing effect, cell proliferation effect, anti-inflammation effect and cell cytotoxicity. Zymomonas mobilis, a microorganism producing Fructan, was cultured in a medium containing 10％ sucrose and 2％ yeast extract as main components for 24 hours at 37$^{\circ}C$ and pH 7. Fructan was obtained by precipitation from the cultured medium by adding alcohol (alcohol ratio of 1:3) after removing the enzyme by centrifuging. Fructan exhibited almost same moisturizing effect as hyaluronic acid and cell proliferation effect on human fibroblast and keratinocyte as well. Moreover, on cell proliferation test on bio-artificial skin constructed by 3-dimensional(3-D) culture after inducing primary skin inflammation with 0.5％ sodium lauryl sulfate (SLS), the 3-D artificial skin treated with 0.01 mg/ml, 0.05mg/ml of Fructan exhibited higher cell proliferation than the 3-D artificial skin treated with SLS only. On anti-inflammation test on 3-D artificial skin evaluated by measuring secreted quantity of interleukin-1$\alpha$ (IL-1$\alpha$) which is a pre-inflammatory mediator induced by SLS, the quantity of IL-1$\alpha$on the 3-D artificial skin treated with 0.01 mg/ml, 0.05mg/ml of Fructan was less than the one on the 3-D artificial skin treated with SLS only. As a result of these studies, Fructan has anti-inflammation effect against inflammatory reaction by a skin irritant as well as cell proliferation effect in bio-artificial skin. Fructan was also evaluated as a safe material without any toxicity in safety tests using fibroblasts and animals.

• Communications for Statistical Applications and Methods
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• v.8 no.1
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• pp.117-126
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• 2001

We provide a simple chi-squared test of multivariate normality based on rectangular cells on the spherical data. This test is simple since it is a direct extension of the univariate chi-squared test to multivariate case and the expected cell counts are easily computed. We derive the limiting distribution of the chi-squared statistic via the conditional limit theorems. We study the accuracy in finite samples of the limiting distribution and then compare the poser of our test with those of other popular tests in an application to a real data.

• Journal of Periodontal and Implant Science
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• v.29 no.1
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• pp.15-30
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• 1999

The purpose of this study was to evaluate the effect of mixed extracts of aralia cortex and phellodendron cortex (P55A) on activities of human gingival fibroblasts and periodontal ligament cells in vitro. First experiment was done to evaluate the effect of P55A in normal condition. In control group, the cells($4.5{\times}10^4$ cells/ml) were cultured with Dulbecco's Modified Eagle's Medium contained with 10% fetal bovine serum. In experimental groups, P55A was added to the above culture condition at the final concentrations of 0.1 ${\mu}g/ml$(Test group 1), 1 ${\mu}g/ml$(Test group 2) and 10 ${\mu}g/ml$(Test group 3). Then each group was tested for the cell proliferation rate at $\frac{1}{2}$, 2, 5 days, protein levels at 2, 5 days, and alkaline phosphatase activity at 2, 5 days. Second experiment was done to evaluate the effect of P55A in high glucose condition. 200 mg/dl glucose was added to the same culture condition of all groups in first experiment. Then each group was tested for the cell proliferation rate at $\frac{1}{2}$ , 2, 5 days, protein levels at 2, 5 days, and alkaline phoaphatase activity at 2, 5 days. The results were as follows ; 1. First experiment 1) As P55A concentration increased, cell proliferation rate increased significantly in test group 2 at 2 days, and test group 2 and 3 at 5 days in human gingival fibroblasts and periodontal ligament cells(P<0.05). 2) In human gingival fibroblasts, all test groups showed significantly increased protein levels as compared to control group at 5 days. In periodontal ligament cells, test group 2 and 3 showed significantly increased protein levels as compared to control group at 2, 5 days(P<0.05). 3) Alkaline phosphatase activity of human periodontal ligament cells increased as P55A concentration increased. The test group 2 and 3 showed significant increase as compared to control group at 5 days(P<0.05). 2. Second experiment 1) As P55A concentration increased, cell proliferation rate increased significantly in test group 2 at 2 days, and test group 2 and 3 at 5 days in human gingival fibroblasts and periodontal ligament cells(P<0.05). 2) In human gingival fibroblasts, test group 3 showed significantly increased protein levels as compared to control group at 2 days, and all test groups at 5 days. In periodontal ligament cells, test group 2 and 3 showed significantly increased protein levels as compared to control group at 2, 5 days(P<0.05). 3) Alkaline phosphatase activity of human periodontal ligament cells increased as P55A concentration increased. The test group 2 and 3 showed significant increase as compared to control group at 2 days, and all test groups at 5 days(P<0.05). From the above results, mixed extracts of aralia cortex and phellodendron cortex appeared to enhance cellular activities including cell proliferation rate, protein levels and alkaline phosphatase activity of human gingival fibroblasts and periodontal ligament cells in normal and high glucose condition. This study suggests that mixed extracts of aralia cortex and phellodendron cortex seem to be able to subside the inflammation of periodontal tissue and regenerate the destructed periodontal tissue.

• The Journal of the Korea Contents Association
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• v.5 no.4
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• pp.188-196
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• 2005

This paper presents a new test data compression and low power scan test method that can reduce test time and power consumption. A proposed method can reduce the scan-in power and test data volume using a modified scan cell reordering algorithm and hybrid adaptive encoding method. Hybrid test data compression method uses adaptively the Golomb codes and run-length codes according to length of runs in test data, which can reduce efficiently the test data volume compare to previous method. We apply a scan cell reordering technique to minimize the column hamming distance in scan vectors, which can reduce the scan-in power consumption and test data. Experimental results for ISCAS 89 benchmark circuits show that reduced test data and low power scan testing can be achieved in all cases. The proposed method showed an about a 17%-26% better compression ratio, 8%-22% better average power consumption and 13%-60% better peak power consumption than that of previous method.

• Journal of Industrial Technology
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• v.17
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• pp.213-218
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• 1997

This study is concerned with characteristics of bending collapse of aluminum members with multi-cell section. Aluminum is light so it is compatible of being used for vehicle structures members. Bending collpase behaviors of aluminum members with multi-cell section are very complex and tension failure mode are occured in experiment. In this paper, the aluminum members are modeled to be able to represent the tension failure mode and, characteristics of bending collapse of aluminum members with multi-cell section by experimental method are compared with the results of PAM-CRASH.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.138-142
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• 1998

This paper has been analyzed, modeled, designed, fabricated, and tested for solar cell simulator which has solar array characteristics. The main purpose is the development of solar cell simulator to test electrical power subsystem for GEO Communication Spacecraft. The maximum power of the simulator is about 5 ㎾, which is consist of 12 independent simulator modules with 420 W power rating. The 12 simulator modules are independently controlled like as real solar array system.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1389-1390
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• 1997

The object of this research is to develop various composing material for Solid Oxide Fuel Cell generation system, and to test single cell performance manufactured. So we try to present a guidance for developing mass power generation system. We concentrated on development of manufacturing process for cathode, anode and electrolyte.

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.743-747
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• 2004

In this study, micro blood separators capable of separating blood cell and blood plasma using microstructure are fabricated and their feasibility and separation performance are evaluated. Test results show the possibility of separating blood cell and blood plasma using microstructure. To improve separation performance and anti-clogging characteristic, technical points of tested micro blood separators are discussed and improved designs are presented.

• Microbiology and Biotechnology Letters
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• v.22 no.4
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• pp.347-352
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• 1994

Cytotoxic test was performed by SRB assay on human epidermoid carcinoma HEp-2 cell line for screening the soil microorganism, secreting anticancer agent. One microorganism was selected among two thousand microorganisms for its highest cytotoxicity. And this microorganism was identified with Streptomyces species after performing of diaminopimeric acid and reducing sugar analysis of cell wall and analysing the cultural characteristics and named Streptomyces sp. SM 1119. The effect of anticancer agent in SM 1119 culture extract on the cell cycle was studied by using GG$_{o}$ synchronized NIH 3T3 cells. The extract inhibited the serum stimulation of GG$_{o}$ NIH 3T3 cell only within 1 hour after serum stimulation but not after 6 hours. The extract also reduced the amount of c-myc mRNA in Colo 320 cell. These results suggest that the anticancer agent in the extract inhibits the progression of cell cycle very early stages, probably from G$_{0}$ to G$_{1}$.