• 대한토목학회논문집
• /
• 제26권2B호
• /
• pp.139-144
• /
• 2006

측벽이 존재하는 개수로 난류흐름에 대한 DNS 자료를 사용하여 레이놀즈 전단응력 및 이차흐름의 생성메커니즘을 규명하였다. 측벽 부근에서 이차흐름의 양상을 보면, 상부 및 하부 모서리 부근에서는 측벽을 향해 침투되는 이차흐름이 형성된 반면, 그 외의 영역에서는 수로 중앙을 향해 분출하는 이차흐름이 형성된 것으로 나타났다. 측벽 부근에서 레이놀즈 전단응력의 분포를 산정하였으며, 고유구조와 연계하여 분석하였다. 사분면 해석에서 측벽을 향해 침투되는 이차흐름이 생성된 영역에서는 쓸기현상이 지배적인 반면, 측벽으로부터 분출되는 이차흐름이 형성된 영역에서는 분출현상이 지배적인 것으로 나타났다. 또한 조건부 사분면 해석을 통해 레이놀즈 전단응력의 생성 및 이차흐름의 양상이 지배적인 고유구조의 방향성에 의해 결정된다는 것을 확인하였다.

• BMB Reports
• /
• 제28권1호
• /
• pp.51-56
• /
• 1995

Thioredoxin is a small redox protein with an active-site disulfide/dithiol, and is ubiquitous in bacteria, plants, and animals. To investigate the structure-function relationship of thioredoxin, the genes encoding Escherichia coli thioredoxin and Corynebacterium nephridii thioredoxin C3 were fused via a common restriction site in the nucleotide sequence coding for the active site of the proteins to generate two chimeric thioredoxins, designated E-C3(N to C-terminal) and C3-E. The hybrid thioredoxin genes were put under the T7 promoter and their productions were confirmed. The two hybrid thioredoxins complemented phenotypes of a thioredoxin-deficient E. coli strain. A strain containing the C3-E hybrid thioredoxin supported growth of the T7 phage, whereas a strain expressing the E-C3 hybrid thioredoxin did not. However, both hybrids supported growth of M13 phages. The two hybrid thioredoxins were also characterized in other aspects. Differences in activity between the hybrid thioredoxins were attributed to altered interactions of the N- and C-terminal domains of the molecule, which produced changes in the three-dimensional structure of the active site region.

• 한국토양비료학회지
• /
• 제8권3호
• /
• pp.161-170
• /
• 1975

Status of agriculture in Jeju province were investigated to find out problems and solutions in view of weather, soils and crop productions. Two hundred harmful windy days per year force to build strong wind-break forest near to farm. Somewhat severe drought situation in croping could be completely avoided by good irrigation system using abundant underground water resources. Poor fertility of soils should be improved by using much compost, lime, fused phosphate, and high dose fertilizers. Optimum fertilizer level for each crop should be determined with special consideration on characteristics of volcanic ash soil.

• International Journal of Internet, Broadcasting and Communication
• /
• 제7권2호
• /
• pp.155-160
• /
• 2015

The objective of this study was to develop the classification method of various organic wastes. Specifically, the effects of proximate composition on the biogas production and degradation rates of agricultural by-production was investigated and a new standards for mixture of various organic wastes based on proximate composition combination was developed. Agricultural by-products (ABPs) with medium total carbohydrate, medium crude protein and low fat contents demonstrated the single step digestion process. ABPs with low total carbohydrate, high crude protein and high fat contents demonstrated the two step digestion process of Diauxic growth. The single ABP (Class No. 15) and the mixed ABPs (Class No. 12+18, 6+12+22, 9+12+18) after 10days showed the similar biogas yield pattern. We can use the classification method for the more ABPs and organic wastes from factory and municipal waste treatment plant for the high efficient biogas production.

• The Korean Journal of Ecology
• /
• 제6권2호
• /
• pp.90-97
• /
• 1983

Seasonal changes of the soil nutrient contents and aboveground biomass, relationship between the soil nutrients and the productivity, and the net efficiencies of solar energy conversion were studied in two reeed communities (Phragmites communis Trin.) at the salt marsh in the estuary of the Sumjin-River from April 30 to October 9, 1981. The inorganic nutrients such as exchangeable sodium and potassium of soil were decreased during growing season. The amounts of organic matter, exchangeable sodium and potassium, total nitrogen, and available phosphorus in stand $\prod$ were much more than those of stand $\coprod$ . Productivity of Phragmites communis was positively correlated with the soil nutrients such as available phosphorus, exchangeable potassium and total nitrogen. The maximum dry matter productions of the aboveground parts in stand $\prod$ stand $\coprod$ were $ 1, 120g/m^2; and; 843g/m^2$ in August, and the net coversion efficiencies of PhAR based on growing season (April to September) were 1.77% and 1.33%, respectively.

• Journal of Advanced Marine Engineering and Technology
• /
• 제30권3호
• /
• pp.359-368
• /
• 2006

The trend on marine diesel engine productions and refinements has led to a higher mean effective pressure and thermal efficiency. These resulted in increased maximum combustion pressure within the cylinder and vibratory torque in crankshaft. In view of this. the crankshaft should be able to withstand the dynamic stresses caused by load variations. Different factors including size, material and stress concentration factors should also be considered to ensure the reliability of the shafting system. As such, crankshaft must be designed and compacted within its fatigue strength. In this paper, the strength analysis of crankshaft Is carried out by: simplified method recommended by IACS(International Association Classification Societies) M53 and a detailed method with the crankshaft assumed as a continuous beam and bearing supported in its flexibility. The results of these two methods are then compared.

• 자원ㆍ환경경제연구
• /
• 제10권4호
• /
• pp.495-513
• /
• 2001

We investigate a practical method of calculating the impact of multiple domestic energy price change on the final demand, production, the export and import change, the change in the balance of payment of Korean economy. By combining an existing computable general equilibrium (CGE) model with the traditional input-output analysis with two additional assumptions on the price behavior, we provide a cost-effective method of analyzing the impact of multiple energy price changes on the domestic economy. The energy price shock we used in this paper is 0.127% increase weighted by the sectoral productions. The total impacts on price level and GDP are 1.258% and -0.940%, respectively. The impact on the total output (GDP and intermediate goods) is about -1.580%.

• Journal of Applied Biological Chemistry
• /
• 제50권3호
• /
• pp.160-163
• /
• 2007

Two flavonoids (1 and 2) and one phenolic acid (3) obtained from Erigeron annuus have recently been shown to have potent antioxidant activities. Aim of this study was to investigate the inhibitory effects of these components on $interferon-{\gamma}$ and lipopolysaccharide-induced nitric oxide productions in the mouse pheritoneal macrophage. Compounds 2 and 3 showed marked inhibitory activities against inducible nitric oxide synthase (iNOS) on the lipopolysaccharide and $interferon-{\gamma}-stimulated$ mouse pheritoneal macrophages without cytotoxicity. Therefore, these results suggest that the compounds could be effective anti-inflammatory agents as nitric oxide inhibitors in vivo.

• 말소리와 음성과학
• /
• 제7권2호
• /
• pp.139-145
• /
• 2015

Researchers have claimed that Korean younger speakers tend to less clearly differentiate aspirated and lax stops with VOT values while older speakers clearly differentiate these two stops with VOT values. To explain this phenomena, the current study consider both an aging effect and a general sound shift. For this study, VOT values and F0 of Korean stops produced by eight male speakers(years of birth were 1942 ~ 1952) analyzed using Praat. Their productions were compared with the values of participants whose year of birth were 1943 ~ 1952) in Silva(2006)'s research. Silva's research was conducted in 2004 using the same methods. The result shows that 2014's VOT gap between aspirated and lax stops and less F0 gap between aspirated and lax stops than those of 2004. When the F0 values related to physical conditions of the larynx is considered, it could be analyzed as the following: to distinguish the three-way phonation type clearly, older speakers depend on the VOT value more instead of F0 which they have difficulty to control.

• 말소리와 음성과학
• /
• 제10권2호
• /
• pp.1-6
• /
• 2018

The current study aimed to investigate the transfer of English word stress rules to the production of Korean trisyllabic words by L1 English learners of Korean. It compared English and Korean speakers' productions of seven Korean words from the corpus L2KSC (Rhee et al., 2005). To this end, it analyzed the syllable duration, intensity, and pitch. The results showed that English and Korean speakers' pronunciations differed markedly in duration and intensity. English learners produced word-initial syllables of greater intensity than Korean speakers, while Korean speakers produced word-final syllables of longer duration than English learners. However, these differences between the two speaker groups were not related to the expected L1 transfer. The tonal patterns produced by English and Korean speakers were similar, reflecting L1 English speakers' learning of the L2 Korean prosodic system.