• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.10
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• pp.82-92
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• 2005

The present study was carried out in order to develop a remote-controlled micro ornithopter with a weight of 20 gram. This ornithopter has three channel radio control. It runs on two direct-current type pager motors powered by a lithium polymer battery which flaps its 35cm wings. The performance of an ornithopter, applied to a flapping motion only, was validated by flight tests. The flight test results indicate that the ornithopter developed here has sufficient thrust to propel itself.

• Aerospace Engineering and Technology
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• v.11 no.1
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• pp.7-18
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• 2012

Full-scale static test was introduced for the KC-100 aircraft which is domestic civil aircraft to be certified for the first time. Test requirement, test frame, and important test stystems such as loading system, counterbalance system, restraint system and jacking system are explained in detail. Especially, the way to satisfy compliance for the installation of test article and loading system is introduced by using check sheets for the installations. 15 Full-scale and 7 local test conditions were successfully completed and the test data was obtained.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.253-253
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• 1994

영지와 구름버섯의 원형질체 융합 균주 F-1의 배양 균사체로 부터 열수추출한 분획 Fr.I을 DEAE-cellulose ion chromatography와 gel filtration chromatography를 통하여 분획 Fr.II, III, IV,로 분리 정제하였다. Sarcoma 180에 대한 종양억제율을 검사한 결과 Fr.IV는 68.73%로 가장 우수하였으며 동계 복수암에 대한 수명 연장 효과도 140 %의 유의적인 결과를 얻었다. 면역 관련 장기의 중량에 대한 영향을 실험한 결과 정상군에 비해 간, 비장 및 흉선의 중량을 증가시켰고, 마우스 암세포에 대한 직접적인 세포독성 작용을 보이지 않았으나 면역 실험을 실시한 결과, 마우스에서 용혈반 형성세포수를 1,36배 증가시켰으며 암이식군에서 감소된 T lymphocyte활성을 정상수준까지 회복시켰고 또, macrophage의 superoxide anion 분비를 2.25배 증가시켰다. 이로써 이 항암 성분은 면역세포를 활성화시켜 항암 효과를 나타냄을 의미한다. Fr.IV히 분자량은 7.9$\times$$10^4$ dalton이고 75,57%의 다당체와 4.47%의 단백질로 이루어졌으며 그 다당체는 주로 glucase, xylose와 mannose로 구성된 heteropolysaccharide이었으며 그 단백질은 Alanine과 Valine을 위시한 15종의 아미노산을 함유하고 있음이 확인되었다.

• Microbiology and Biotechnology Letters
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• v.33 no.4
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• pp.288-294
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• 2005

Flavonoid compounds show several biological activities and generally exist in the forms of glycones linking sugar moiety to main structure. Flavonoid glycones such as naringin and hesperidin in korean citrus peel are slower absorbed and consequently less active than their aglycone, naringenin and hesperetin, respectively. Therefare to increase the content of flavonoid aglycone in korean citrus peel, we used commercial carbohydrate-hydrolysing enzymes, AMG 300 L, Pectinex 100 L, and Viscozyme for transforming flavonoid glycones to aglycones. Optimal conditions of enzyme reaction were pH 5.0-7.0, $5\%$ enzyme, and 24-48 hrs. The content of naringenin and hesperetin as flavonoid aglycones in untreated citrus peel is $100\~200\;ng/g$ of dried citrus peel. In case of enzyme-treated citrus peel the content of naringenin and hesperetin increased to $1,539\∼6,674\;ng/g\;and\;1,974\∼8,906\;ng/g$ of dried citrus peel, respectively. Finally the content of flavonoid aglycones could be extracted to 10-80 times. Now enzyme-treated citrus peel may be applied to use for functional food because of its higher flavonoid aglycones as more active compounds.

• International Journal of Highway Engineering
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• v.6 no.3 s.21
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• pp.55-64
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• 2004

Maximum dry unit weight, ${\gamma}_{dmax}$, is the most important engineering properties for subgrade soil. Existing models to predict ${\gamma}_{dmax}$ containing many parameters, seem to be rather complex. This paper presents new simple models to predict ${\gamma}_{dmax}$. for sandy soils, A number of sieve analysis and compaction tests for 36 types of sands were conducted to develop the regression-based models. Parameters used to estimate ${\gamma}_{dmax}$ are both the geometric mean and geometric standard deviation of the soils, or the particle-size distribution curve parameters. Maximum dry unit weights predicted by the models are in good agreement with the laboratory measurements for the soil samples obtained at 16 locations within the Korea.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1995.04a
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• pp.349-356
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• 1995

플라스틱 압출제품의 품질특성은 제품의 강도인데 제품의 강도는 일반중소기업체에서 별도의 측정기구를 갖추고 관리하기가 어려우므로 대용특성으로 제품이 중량을 사용하고 있다. 제품의 중량은 실린더의 온도와 금형의 온도 및 압출속도에 영향을 받는데 일반적으로 현장작업자의 경험과 감에 의존하여 상황에 따라 작업조건을 변화시켜 관리하고 있다. 그런데 작업조건을 관리하는 곳이 실린더에 5군데, 금형에 3군데 및 압출속도 등 아홉가지로 어느 인자가 전체 작업에 영향을 미치는 지 알수 없다. 이때 중회귀(Multiple Linear Regression)모델을 이용하여 실린더와 금형의 온도를 독립변수(Independent Variable)라 두고 제품의 중량을 종속변수(Dependent Variable)로 하여 최근 3개월간의 작업데이타를 수집하여 품질관리 전용 프로그램인 JUSE-QCAS를 사용하면 회귀선의 모수를 쉽게 추정할 수 있으며 제품의 중량에 영향을 미치는 실린더 및 금형의 온도를 관리 할 수 있어 품질을 안정적을 유지.관리할 수 있다.

• Elastomers and Composites
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• v.43 no.3
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• pp.157-165
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• 2008

Suspension polymerization was carried out to synthesize poly(butyl methacrylate) (PBMA) composite particles containing carbon black. Water was selected as a reaction medium, hydrophobic silica as a stabilizer and azobisisobutyronitrile as an initiator. Concentration of stabilizer was varied from 0.67 to 2.55 weight% with respect to the water, and that of initiator was varied from 0.25 to 3.00 weight% with respect to the butyl methacrylate (BMA) monomer. All polymerization reactions were conducted at 75$^{\circ}C$. It is found that stabilizer concentration has no impact on reaction kinetics, while an increase in initiator concentration enhances polymerization reaction rate. Increase of carbon black concentration from 1 to 3 to 5 wt% into PBMA displayed progressive decrease in reaction conversion. The particle diameter of PBMA composite particles containing carbon black was found to be between 5 and 30 ${\mu}m$. Glass transition was determined to range from 23.8 to 24.7$^{\circ}C$, irrespective of variation in the concentration of stabilizer, initiator or carbon black.

• The Korean Journal of Pesticide Science
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• v.16 no.4
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• pp.383-386
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• 2012

Streptomyces spp. were isolated from rhizosphere in fallow lands. The Streptomyces spp. were identified as Streptomyces griseus (MSS181), Streptomyces griseoaurantiacus (MSS269), Streptomyces microflavus (MSS275), Streptomyces herbaricolor (MSS276) based on 16S rRNA gene sequences. Afterwards, cucumber, pepper, tobacco and tomato were drenched with the isolates at early growth stages and plant growth such as height and dry weight of plants was measured. By treatment of Streptomyce spp., plant height of cucumber was increased by 16-29% compared to the control, But there were no statistically significant differences in dry weight. When the same isolates were treated on chili-pepper, plant height and dry weight of chili-pepper were increased respectively by 10-19% and 19-25% compared to the control. The dry weight of tobacco and tomato were increased by 44-73% and 65-165%, respectively compared to the control. When antifungal activities of the isolates were tested against plant pathogenic fungi, Streptomyces microflavus (MSS275) effectively inhibited the mycelial growth of Phytophthora capsici, Fusarium oxysporum, Rhizoctonia solani and Sclerotinia sclerotiorum.

• Journal of Ocean Engineering and Technology
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• v.27 no.6
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• pp.22-26
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• 2013

The purpose of this study was to improve the design of a mooring line by attaching a lumped mass to it on the seabed. A numerical analysis of the redesigned mooring system is performed to analyze the effect of the weight of the attached lumped mass using the commercial software Orcaflex. The ultimate tension of the mooring system with the lumped mass is compared with that of a bare mooring line in the original design. An appropriately designed weight for the lumped mass is found to induce a critical lifted point in the mooring line by floater motion in the ultimate condition to move toward the floater position from the anchor point, while maintaining a similar safety factor for the mooring line. On the other hand, it is shown that excess weight for the lumped mass induces snapping in a mooring line, resulting in low safety factor for the mooring system. The distance between lumped weights is shown to be a minor parameter affecting the safety of a mooring line, although a shorter line has an advantage from an economic point of view. Using the optimal weight for the lumped mass attached to the mooring line on a seabed reduces the mooring line length and installation area occupied by a mooring system under real sea conditions.

• Fire Science and Engineering
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• v.26 no.4
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• pp.42-47
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• 2012

In the study, fire extinguishing concentration of $K_2CO_3$-Zeolite composite was measured. Zeolite composite is a porous adsorbent which has small particle size, low density and anti-catalytic effect. Scanning Electron Microscopy, X-Ray diffraction and thermal analysis were also conducted to investigate the structural properties of composite. The result showed that despite of weight ratio, the extinguishing concentration of the composite was lower than pure $K_2CO_3$. The extinguishing concentration of $K_2CO_3$-Zeolite composite which has weight ratio of 7 : 3 was 5.72 times lower than that of pure $K_2CO_3$ and 1.1 times lower than that of ABC powder. The SEM and XRD patterns showed that $K_2CO_3$ was adsorbed on the Zeolite properly, and through the thermal analysis, it was founded that the composite is more effective extinguishing agent than pure $K_2CO_3$.