• 한국기계가공학회지
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• 제16권2호
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• pp.22-27
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• 2017

During the water treatment process for household water supply, a reservoir is the last place the water is stored before being supplied to users, and the duration of the water's stay is an important factor that affects its safety. This may cause the concentration of the residual chlorine disinfectant to increase and thus lower the water's quality. The concentration and discharge efficiency of residual chlorine must be verified and managed, because these are key factors that affect the reservoir's performance. Because the actual verification test for analyzing the efficiency of a reservoir and the disinfectant's dilution capacity is difficult, simulations are generally conducted using the computational fluid analysis method. However, the simulation results require validation with experiments. The error and drainage efficiency were analyzed in this study by comparing and analyzing the actual tracer test and simulation so that the actual test for a hexagonal drainage can be replaced by the computational fluid analysis method. Based on the results of the efficiency analysis, the hexagonal reservoir was found to be appropriate, and the simulation's reliability was verified with a tracer test.

• 한국패류학회지
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• 제24권1호
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• pp.51-57
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• 2008

With the purpose to estimate the possibility of short-term storage and cryopreservation for sperm of Charonia sauliae, which is a potential preparation for its artificial reproduction and further research, in this study, protocols for short-term storage and cryopreservation of trumpet shell sperm was optimized. The effects of different immobilizing solutions, dilution ratios were estimated for short-term storage. And the effects of different cryoprotectant extenders and freezing rates were estimated for cryopreservation in terms of motility and survival of sperm. The results indicated that the artificial sea water of 350 mOsmol/kg is a better immobilizing solution and sperm which was diluted at a ratio of 1:1 (v/v) had higher motility and survival rate during short-term storage. The effect of 5% dimethyl sulfoxide was significantly better than those of other cryoprotectant extenders. And a freezing rate of $-20^{\circ}C\;min^{-1}$ showed better effect than other freezing rates. In conclusion, this study optimized some key factors of the short-term and cryopreservation of C. sauliae sperm, which can provide valuable data for germ-plasm conservation and artificial propagation of C. sauliae.

• Journal of Microbiology and Biotechnology
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• 제8권1호
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• pp.8-13
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• 1998

Animal cells in culture typically convert most of the glucose they consume into lactate. The accumulation of lactate, however, is commonly cited as one of the factors that inhibit cell growth and limit the maximum cell concentration that can be achieved in culture. The specific production of lactate and the amount of glucose converted to lactate can be reduced when cells are grown in a fed-batch culture in which the residual glucose concentration is maintained at low levels. Such a fed-batch culture was used to grow and adapt hybridoma cells into a low-lactate-producing state before changing into continuous culture. The cells reached and maintained a high viable cell concentration at steady state. In a similar manner, cells that were initially grown in batch culture and a glucose-rich environment reached a steady state with a cell concentration that is much lower. The feed composition and dilution rates for both cultures were similar, suggesting steady state multiplicity. From a processing perspective the desired steady state among those is the one with the least metabolite production. At such seady state nutrient concentration in the feed can be further increased to increase cell and product concentrations without causing the metabolite inhibitory effect typically seen in a cell culture. Controlling cell metabolism in a continuous culture to reduce or eliminate waste metabolite production may significantly improve the productivity of mammalian cell culture processes.

• 약학회지
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• 제35권2호
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• pp.61-72
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• 1991

These studies were made to assess the present stage of resistance to antibiotics, incidence and transferability of R-factors against E. coli. From March to July 1987, 59 strains of E. coli were isolated from specimens of patients collected at university hospitals in Seoul, 64 strains from stools of domestic animals and 66 strains from drainages in Seoul. These specimens were tested for resistance to 12 kinds of antimicrobial agents by means of agar dilution method. Using Muller-Hinton agar for the assay of drug resistance and tryptic soy broth as propagating medium for conjugation. The strains of E. coli were found to be resistant to one or more antibiotics and were considered to be potential donors of R-plasmid. The resistant strains of E. coli isolated from patients, domestic animals and drainages were found to be 55(93%), 33(52%) and 31(47%), respectively. Resistance to Tc, Ap and Cb was the highest in those isolated from patients and drainages, and resistance to Tc, Cm and Sm was the highest in those isolated from domestic animals. In the transfer test of drug resistance by conjugation method, 17 strains (47%) isolated from patients, 15(54%) isolated from domestic animals and 15(56%) isolated from drainages showed positive results, transperable resistant plasmid molecules with variable range in each strain.

• Journal of Plant Biology
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• 제20권2호
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• pp.77-82
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• 1977

The inhibiotory effect of ethphon on the flowering in Lemna perpusilla 6746 was shown to be related to sucrose concentrations and dilution factors of Hutner's medium. When grown in 1/10-strength Hutner's medium under 10(14) cycles, the plants have been completely inhibited in the floral induction by ethephon (>5ppm) in the presence of sucrose (>20 mM) in the meduim. However, in a less diluted Hutner's medium (1/2-strength), the inhibition of flowering by ethephon was observed to be partially diminished by sucrose at a high concentration (30mM), while a low concentration of sucrose enhanced the inhibitory effect of ethephon in flowering. As inductive dark periodswere extended, the effects of both compounds were partially nullified. Since no significant amount of ethylene possibly released in ethephon decomposition in the medium was detected, the inhibitory effect of ethephon in flowering was postulated to be exerted only through ethylene production within the plants. Plants were incubated in 10 ppm ethephon-containing medium during either dark or light periods, singly or periodically. The most effective single treatment with ethephon was observed during the 4th dark period, when formation of floral stimulus was assumed to be completed beyond a critical level. This postulation can be partially supported by a fact that the plants should be exposed to at least more than four consecutive 10(14) cycles for flowering.

• The Plant Pathology Journal
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• 제21권3호
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• pp.244-251
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• 2005

The induction of growth promotion on numerous crops by rhizobacteria is a well documented phenomenon. In case of tomato (Lycopersicon esculentum), fruit yield is higher in replant soil than that in fresh soil. To investigate what kind of rhizobacterium is involved, microbial community in rhizosphere and on rhizoplane of tomato plants from each soil was analyzed by dilution plating on selective media. Many Gram-negative bacteria and actinomycetes were isolated from tomato in replant soil. One Gram-negative rhizobacterium isolated was identified as Pseudomonas putida based on its biochemical characteristics, fatty acid methyl ester analysis and 16S rDNA sequence. This bacterium designated strain 17 inhibited the growth of Pseudomonas corrugata, and increased growth of tomato seedlings. In addition, its culture filtrate inhibited conidial germination of plant-pathogenic fungi such as Fusarium oxysporum f. sp. radicis-lycopersici, F. oxysporum f. sp. cucumerinum, and Nectria radicicola. Scanning electron microscopy revealed strain 17 colonized and persisted on the epidermal surfaces of tomato radicles and roots. These results suggest that P. putida strain 17 may serve as a biological control agent to suppress multiple soil-borne diseases for tomato plants. Increased microbial populations that suppress deleterious microorganisms including pathogens could be one of the major factors in increased tomato yield in replant soil.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.275-275
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• 2012

The relative composition of $Cu(InGa)Se_2$ solar cells is one of the most important measurement issues. However, quantitative analysis of multi-component alloy films is difficult by surface analysis methods due to severe matrix effect. In this study, quantitative depth profiling analysis of CIGS films was investigated by secondary ion mass spectrometry (SIMS). The compositions were measured by SIMS using the alloy reference relative sensitivity factors derived from the certified compositions and the total counting numbers of each element. The compositions measured by SIMS were linearly proportional to those by inductively coupled plasma-mass spectrometry (ICP-MS) using isotope dilution method. In this study, the quantification measured by ICP-MS method is compared with the composition calculated by SIMS depth profiles with AR-RSFs obtained from the reference. The SIMS depth profile of CIGS thin films according to the manufacturing condition was converted into compositional depth profile.

• 농약과학회지
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• 제3권2호
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• pp.86-89
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• 1999

일련의 methanesulfonamide(Ia-Ig)와 phenylhydrazone(IIa-IIh) 유도체를 합성하고 식물성 병원균인 잿빛 곰팡이병균(BC: Botrytis cinerea), 고추 역병균(PC: Phytophthora capsici) 및 문고병균(RS: Rhizoctonia solani)에 대한 살균활성을 한천 희석법으로 측정하였다. 살균활성은 (I)보다 (II)가 다소 큰 영향을 미쳤으며 (I)과 (II) 모두 PC=BC>RS의 순서로 살균활성을 나타내었다. 다루어진 화합물 중에서 3-chlorophenyl 치환체, IIg가 PC균에 대하여 가장 강한 활성 ($pI_{50}=3.96$)을 보였다. 또한, parameter focusing을 통하여 검토된 살균활성에 미치는 요인들로는 Ovality, 극성 및 logP상수 등이었다.

• Bulletin of the Korean Chemical Society
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• 제25권8호
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• pp.1133-1136
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• 2004

The need for highly reliable methods for the determination of trace metals is recognized in analytical chemistry and environmental science. A method based on the cloud-point extraction (CPE) technique for the trace analysis of Pb and Cu in water samples is described in this study. The analytes in the initial aqueous solution are complexed with pyrogallol, and 0.1%(w/v) Triton X-114 is added as surfactant. Following phase separation at $50^{\circ}C$, based on the cloud point of the mixture and dilution of the surfactant-rich phase with acidified methanolic solution, the enriched analytes are determined by flame atomic absorption spectrometry. After optimization of the complexation and extraction conditions, the enrichment factors of Pb and Cu were found to be 72 and 85, respectively. Under optimum conditions, the preconcentration of 60 mL of samples in the presence of 0.1%(w/v) Triton X-114 permitted the detection of 0.4 ${\mu}gL^{?1}$ of Pb and 0.05 ${\mu}gL^{?1}$ of Cu. The proposed method was applied successfully to the determination of Pb and Cu in water samples.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2019년도 학술발표회
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• pp.412-412
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• 2019

Nature-based solutions (NBS) offer a wide variety of techniques that promote cost-efficient stormwater management practices. In particular, low impact development facilities utilize NBS principles to restore the ecosystem services in a highly-urbanized area. Despite the advancements in these technologies, several considerations should still be addressed to ensure optimum functionality and attainment of desired pollutant removal efficiency a LID facility. This study evaluated the mass flushing characteristics of pollutants in an urban catchment and the efficiency of a small constructed wetland (SCW) in treating urban stormwater runoff. 21 rainfall events from 2010 to 2018 were monitored to determine and quantify stormwater pollutants. The highest pollutant washoff was observed on rainfall depths ranging from 0.1mm to 10mm, whereas events with greater rainfall depths exhibited lower pollutant concentrations due to dilution effect. However, the SCW manifested lower pollutant-removal performance on rainfall depths exceeding 10mm due to the exceedance of the facility's design rainfall. This study is beneficial in assessing the dynamics of pollutant washoff and efficiency of LID facilities subjected under various external factors.