• 환경생물
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• 제37권2호
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• pp.189-195
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• 2019

인산염 농도 변화에 따른 Hizikia fusiforme의 무기비소 축적량 및 생장률을 분석하였다. 무기비소에 14일간 노출하였을 때, 2 mg L^-1의 높은 인산염 농도에서 무기비소 축적량이 증가하지 않았다. 하지만 인산염 농도가 0.02 mg L^-1로 낮은 경우에 무기비소 축적량이 3배 이상 증가하였다. 또한 H. fusiforme는 인산염 농도가 낮은 경우 생장률이 14.5%, 무기비소(10 ㎍ L^-1)에 노출되었을 경우 생장률이 대조구 대비 30% 감소하였다. H. fusiforme는 인산염과 무기비소를 구분하지 못하여 인산염의 농도가 낮은 경우 무기비소 축적량이 증가하게 되고, 축적된 무기비소는 광합성 저해 및 세포분열을 방해하여 생장률을 억제한다. 특히 우리나라의 대표적인 양식생물인 H. fusiforme는 다른 해조류에 비해 상대적으로 무기비소 축적량이 높다고 알려져 있기 때문에, H. fusiforme의 식품안전성을 확보하기 위해 다양한 연구가 필요하다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2006년도 학술발표회 논문집
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• pp.360-364
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• 2006

The physical characteristics of suspended solid in urban watersheds are estimated and are described the accumulation processes on the urban surface. And build up the accumulation model which has two parameters and three constants. Two parameters are $p_0\;and\;p_{max'}$, and three constants are landuse, clean and traffic constant. Suggested model is applied three industry watershed which has variable area. And simulated results are compared with observed data. The model estimates the real phenomenon and the results are pretty good. The simulated accumulation mass are 1.20, 0.96 and $2.88g/m^2$. The differences of simulation and observation data are about 30%.

• International Journal of Industrial Entomology and Biomaterials
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• 제35권1호
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• pp.1-6
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• 2017

In relation to the global increase trend of obesity population, there is a demand for the development of foods having high functional activity by mass-extracting anti-obesity active substances using mulberry product such as leaf and fruit. Therefore, we evaluated the antiobesity efficacy according to varieties by using the mulberry leaves and fruit extracts. At the same time, high active varieties were selected. For this purpose, the effects of the extracts of the mulberry leaf and fruit on 3T3-L1 adipocyte differentiation were examined. As a result, in the case of mulberry leaves, the lipid accumulation inhibitory rate of 'Cheongolppong' was higher than that of the control at $500{\mu}g/ml$ treatment. And in the case of the extract of mulberry fruit, 'Daesim' showed the highest lipid accumulation inhibitory rate compared with the control at 50 times of diluted extract.

• Journal of the korean society of oceanography
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• 제31권4호
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• pp.207-216
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• 1996

A geochemical study of three piston cores (ST.4, ST.6 and ST.20) taken from the Northwest Pacific (eastern edge of Shikoku Basin) provides information about changes in surface water paleoproductivity and sedimentation during the last 127 kys. Paleoproductivity variations were estimated on the basis of total organic carbon content and carbonate mass accumulation rate. The paleoproductivity based on total organic carbon shows significant spatial variations between glacial and interglacial periods. During the last glacial maximum (LGM) paleoproductivity increased about 1.5 times with deglaciation decrease compared with those of the Holocene at inner side of the Shikoku Basin (ST.4 and ST.6). On the other hand, paleoproductivity at outer side of Shikoku Basin (ST.20) indicating not distinctive increase but deglaciation increase. The C/N ratios fall below 10 for cores ST.4 and ST.6, but C/N ratios between 100 ka and 80 ka in ST.20 which show around 10 or larger values suggest a predominance of marine organic carbon with some admixture of terrigenous materials. The carbonate mass accumulation rate of three cores show different patterns of calcareous record with respect to organic carbon based paleoproductivity variation. In the inner side of Shikoku Basin (ST.4 and ST.6) the carbonate mass accumulation rate decreased during last glacial maximum, and significant increase of carbonate mass accumulation rate is recognized at outer side of Shikoku Basin (ST.20). Thus, this set of data reveals that spatial paleoproductivity variations between inner and outer side of Shikoku Basin during the glacial and interglacial periods.

• 분석과학
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• 제6권5호
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• pp.425-433
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• 1993

oxine을 리간드로 이용하여 흡착벗김 전압전류법으로 극미량의 지르코늄을 정량하는 방법을 연구하였다. 이때 지지전해질은 $2.5{\times}10^{-3}M$ borax 완충용액을 사용하였고, oxine의 농도가 $4{\times}10^{-8}M$로 되도록 하여 실험하였다. accumulation potential을 -0.2V, accumulation time을 400sec로 하고 scan rate를 4mV/sec로 하여 실험한 결과 지르코늄의 농도가 $1{\sim}100{\mu}g/L$ 범위에서 얻은 검정곡선은 직선성을 나타내었다.

• Environmental Engineering Research
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• 제20권3호
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• pp.246-253
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• 2015

The effects of carbon-to-nitrogen (C/N) ratio in simulated rice straw hydrolysates using glucose and ammonium chloride on polyhydroxyalkanoates (PHA) accumulation by Cupriavidus necator was investigated. In general, PHA accumulation rate was higher under higher degrees of N-deficient conditions (e.g., C/N ratio of 360:1) than lower degrees of N-deficient conditions (e.g., C/N ratio of 3.6:1 and 36:1). Also, the most PHA accumulation was observed during the first 12 h after the PHA accumulation initiation. This study showed that the similar PHA accumulation could be achieved by using different accumulation periods depending on C/N ratios. N source presence was important for new cell production, supported by approximately ten times greater PHA accumulation under the N-deficient condition ($NH_4Cl$ 0.01 g/L) than the N-free (without $NH_4Cl$) condition after 96 h. C/N ratio of the rice straw hydrolysate was approximately 160:1, based on the glucose content, and this accumulated $0.36{\pm}0.0033g/L$ PHA with PHA content of $21{\pm}3.1%$ after 12 h. Since external C or N source addition for C/N ratio adjustment increases production cost, an appropriate accumulation period may be used for PHA accumulation from organic wastes, based on the PHA accumulation patterns observed at various C/N ratios and C and N concentrations.

• 한국물환경학회지
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• 제24권3호
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• pp.383-390
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• 2008

Recently, the interests on economical nitrogen removal from wastewater are growing. As a method of the novel nitrogen removal technology, nitrogen removal via nitrite pathway by selective inhibition of free ammonia and free nitrous acid on nitrite oxidizing bacteria have been intensively studied. The inhibition effects of free ammonia and free nitrous acid are low when domestic wastewater is used, however, because of its relatively lower nitrogen concentration than the wastewater from industry and landfill, etc. In this study, a sequencing batch reactor (SBR) is proposed for nitrogen removal to investigate the effect of the low nitrogen concentration on nitrite accumulation. Nitrification efficiency reached almost 100% during the aerobic cycle and the maximum specific nitrification rate ($V_{max,nit}$) reached $17.8mg\;NH_4{^+}-N/g\;MLVSS{\bullet}h$. During the anoxic cycle, average denitrification efficiency reached 87% and the maximum specific denitrification rate ($V_{max,den}$) reached $9.8mg\;NO_3{^-}-N/g\;MLVSS{\bullet}h$. From the analysis the main reason of nitrite accumulation in the SBR was free nitrous acid rather than free ammonia. Nitrite accumulation increased with the decrease of organic content in the wastewater and the mechanism is not well understood yet. From the result of fluorescent in situ hybridization, the distribution of nitrite oxidizing bacteria was in equilibrium with ammonium oxidizing bacteria when nitrite accumulation did not occur.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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• pp.346-349
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• 2000

In order to investigate the characteristics for RNA accumulation, continuous cultures of S. cerevisiae MTY62 under the carbon-limitation or carbon-phosphate-limitation were performed. In the carbon-limited chemostat, the highest RNA content of 144 mg-RNA/g-dry cell was observed at the dilution rate of $0.30\;hr^{-1}$. In the carbon and phosphate-limited chemostat, the culture condition with the dilution rate of $0.25\;hr^{-1}$ gave the maximal RNA content of 209 mg-RNA/g-dry cell. The accumulation rate of RNA $(mg-RNA/L\;{\cdot}\;hr)$ was decreased at higher dilution rate in the carbon and phosphate-limited chemostat.

• 제어로봇시스템학회논문지
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• 제10권1호
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• pp.96-102
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• 2004

For sensitivity enhancement, the general assisted-GPS acquisition method adopts not only the coherent accumulation technique but also the non-coherent accumulation technique since the long coherent accumulation period increases the number of frequency search cells. But the non-coherent accumulation technique causes tile squaring loss, which is a dominant factor among the acquisition losses of assisted GPS dealing with weak GPS signals. This paper derives the squaring loss of the previous assisted-GPS acquisition method and proposes an assisted-GPS acquisition method for solving the problem of squaring loss in weak signal environment. In this paper, it is explained that the proposed assisted-GPS acquisition method prevents the squaring loss using a coupled coherent accumulation technique and the number of search cells of the proposed assisted-GPS acquisition method is much smaller than that of the previous assisted-GPS acquisition method. Finally, through the simulation by the GPS simulator, the acquisition success rate of the proposed assisted-GPS acquisition method is compared with that of the previous assisted-GPS acquisition method and the acquisition improvements are shown in weak signal environment.

• 신재생에너지
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• 제5권3호
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• pp.49-55
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• 2009

Human resource for the new and renewable energy technology is an important factor in the respect of the sustainable growth and energy security. In this paper, we focused on measuring the economic effect of human resource development on new and renewable energy development programs. The human capital accumulation model developed by Mincer (1974) was modified in terms of the rate of the researchers' investment in human capital. As a result of a empirical case study, the value of human capital was estimated by 102 million Korean won per year worth 18% of the project labor cost. In case of the assumption of 100% participation of researchers, the level of human capital accumulation increased to 914 million Korean won per year. These results imply that the new and renewable energy development programs has been successful, on the concept of learning by doing, in terms of providing the researchers with opportunities to accumulate human capital.