• Analytical Science and Technology
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• v.25 no.2
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• pp.146-151
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• 2012

An analytical method was developed for the measurement of uranium isotope in ground water using the liquid scintillation counting technique. A LKB Wallac Quantulus 1220 liquid scintillation counter (LSC) equipped with pulse shape analyzer (PSA) and a solvent extraction method were used for the measurement of uranium isotope in ground water samples. The effect of solution volume on the extraction efficiency was evaluated for 100 to 1000 mL solutions using a NIST standard reference material (NIST SRM 4321C). The effect of groundwater pH on the extraction efficiency was also investigated for pH ranging from 0.5 to 10. It was found that the extraction efficiency had a strong dependence on pH showing a maximum at pH 2. In contrast, the effect of groundwater volume on the extraction efficiency was negligible in the range investigated. According to the method, the extraction efficiency of uranium isotopes was near 96% and the lower detection limit for uranium was 0.018 Bq/L with the counting time of 300 min. The result of this study was also verified by the conventional ICP-MS measurement. It is demonstrated that the suggested method is valuable to the determination of the optimum extraction and measurement conditions for uranium in ground water. The method was successfully applied to the ground water at four locations near the Daejeon province. It was found that the uranium content and the isotopic ratio of $^{234}U/^{238}U$ at the locations ranged 0.59~6.69 Bq/L and 0.72~1.40, respectively.

• Journal of the Ergonomics Society of Korea
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• v.29 no.4
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• pp.647-654
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• 2010

In a service environment, the spatial layout is an important factor that has a great impact on customers' behavioral characteristics including wayfinding and purchasing. Previous studies have shown a gap between marketing, focusing solely on profitability and satisfaction, and architecture, looking only into efficiency of pedestrian flow. To balance such disparity, this study suggests an integrated approach for assessing behavioral patterns in complex service environments. With the objective that complex service environments should aim to increase its profitability and efficiency while guaranteeing customer satisfaction, quantitative metrics was developed for evaluation. The metrics was defined to use data from behavior observation including path tracking, population counting, and gaze analysis, while previous studies have relied on abstract survey methods that were prone to sampling errors and loss of data. For validation of the metrics in a real world setting, a case study was conducted at 4 train stations in Korea. In the case study, experiments were conducted to gather the required data in all 4 train stations, while their physical layouts were also analyzed. With the results from the case study, comparative evaluation of the 4 train stations in terms of behavioral efficiency was possible, together with a discussion on the effect of their physical settings.

• Journal of environmental and Sanitary engineering
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• v.13 no.2
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• pp.156-164
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• 1998

This study was performed to select media for the development of biological activated carbon process. Using activated carbon made by Norit, Calgon, Samchully Co., removal efficiency of humic acid by the isothermal adsorption test and biodegradation of organic matters by microbes attached to BAC and observation and counting of microbes attached to BAC were examined. The removal efficiency of humic acid with dose of activated carbon was influenced by initial concentration. Compared with other activated carbon, Norit was found to be most effective in view of adsorption capacity, biodegradation of organic matter, and attachment characteristics of microorganism. In conclusion, Norit which has high adsorption capacity and good biodegradation of organic matter was recommended for selecting media in BAC process.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.5
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• pp.834-840
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• 2001

A real time multibody vehicle dynamics model has been developed and implemented using a subsystem synthesis method based on recursive formulation. To verify real time simulation capability the developed model has been applied to HMMWV(High Mobility Multipurpose Wheeled Vehicle) with steering system. For the kinematically driven steering system, the coupled front suspension-steering subsystem can be decoupled into two SLA suspension subsystems, which improves the efficiency of simulation. To investigate theoretical efficiency, operational counting method has been also employed to compare the proposed model with the conventional recursive dynamics model. Various simulations such as unsymmetric bump run, step steering(J-turn) and sine steering input test have been carried out to verify the real time feasibility of the proposed model.

• Journal of the Semiconductor & Display Technology
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• v.3 no.2
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• pp.1-4
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• 2004

An experimental study was conducted on the optimal configuration and size of ADFL(Aerodynamic Focusing Lens) which used in modified ISPM(In-Situ Particle Monitoring). The particle counting efficiency has been known as a function of distance and size of ADFL, thus we varied these parameters to find out the optimum values. From a result of experiment, it was found that two lenses and 6mm space between them showed a maximum particle measuring efficiency. To apply this modified ISPM to semiconductor manufacturing field, we need more experiment about the pressure change, flow rate, and input particle size.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.3
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• pp.194-201
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• 2003

This study presents the comparative filtration performance evaluation of automotive fuel filters based on the theory of Beta ratio. For the experiments, the fuel component's test stand incorporating the multi-pass filtration test circuit was developed. A mathematical description of filtration process in general was derived. And the theoretical basis of multi-pass test and the test procedure were described in detail. Experimental results revealed that domestic fuel filter tested could not maintain consistent Beta ratio, that is filtration efficiency, although it had the holding capacity of contaminants close to the specification at maximum pressure drop across the filter assembly. The results of experiments and simulations also showed that filtration system model could be refined including desorption ratio to estimate the variable Beta ratio in service life.

• Particle and aerosol research
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• v.19 no.3
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• pp.77-87
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• 2023

We present the development of a wetcyclone sampler designed for the sampling of airborne bacteria. The wetcyclone design involves a combination of two traditional cyclone shapes and computational fluid dynamics (CFD) analysis to validate its effectiveness in terms of pressure drop and collection efficiency. The wetcyclone exhibits a collection efficiency of over 90% for bacteria, specifically targeting Staphylococcus aureus. Additionally, the wetcyclone enables continuous bioaerosol sampling using a liquid medium (deionized water), demonstrating a concentration ratio exceeding >105 and a stable microbial recovery rate of 81.9%. The application of real-time quantitative polymerase chain reaction (qPCR) and the colony counting method ensures precise measurement of the concentration ratio and microbial recovery rate.

• Nuclear Engineering and Technology
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• v.51 no.2
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• pp.526-532
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• 2019

In this study, an in-house $^{152}Eu$ calibration source was produced from a custom epoxy matrix with a density of ${\rho}=1.14g\;cm^{-3}$, which is chemically stable and durable form after its solidification. The homogeneity of $^{152}Eu$ in matrix was obtained better than 98%. For a Marinelli beaker geometry, an efficiency calibration procedure was applied to a n-type, coaxial, 78.5% relative efficient HPGe detector in the energy range of 121.7-1408.0 keV by using in-house $^{152}Eu$ calibration source. Then the measured efficiencies for Marinelli geometry were compared with the results calculated by MEFFTRAN and ANGLE softwares for the validation. Although MEFFTRAN and ANGLE have two different efficiency transfer algorithms to calculate the efficiencies, they usually need to use a reliable and accurate reference efficiency values as input data. Hence, reference efficiency values were obtained experimentally from a multinuclide standard source for the same detector-Marinelli geometry. In the present source characterization, the corrections required for self-absorption and true coincidence summing effects for $^{152}Eu$ gamma-rays were also obtained for a such close counting geometry condition. The experimental results confirmed the validity of efficiency calculations obtained by MEFFTRAN and ANGLE softwares that are calculation tools.

• Korean Journal of Environmental Agriculture
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• v.40 no.3
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• pp.186-193
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• 2021

BACKGROUND: Before generating transgenic plant using the CRISPR-Cas9 system, the efficiency test of sgRNAs is recommended to reduce the time and effort for plant transformation and regeneration process. The efficiency of the sgRNA can be measured through the transient expression of sgRNA and Cas9 gene in tomato cotyledon; however, we found that the calculated efficiency showed a large variation. It is necessary to increase the precision of the experiment to obtain reliable sgRNA efficiency data from transient expression. METHODS AND RESULTS: The cotyledon of 11^th, 15^th, 19^th, and 23^rd-day-old tomato (Solanum lycopersicum cv. Micro-Tom) were used for expressing CRISPR-Cas9 transiently. The agrobacterium harboring sgRNA for targeting ALS2 gene of tomato was injected through the stomata of leaf adaxial side and the genomic DNA was extracted in 5 days after injection. The target gene edition was identified by amplifying DNA fragment of target region and analyzing with Illumina sequencing method. The target gene editing efficiency was calculated by counting base deletion and insertion events from total target sequence read. CONCLUSION: The CRISPR-Cas9 editing efficiency varied with tomato cotyledon age. The highest efficiency was observed at the 19-day-old cotyledons. Both the median and mean were the highest at this stage and the sample variability was also minimized. We found that the transgene of CRISPR-Cas9 system was strongly correlated with plant leaf development and suggested the optimum cotyledon leaf age for Agrobacterium-mediated transfection in tomato.

• Journal of Industrial Technology
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• v.29 no.A
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• pp.83-88
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• 2009

The removal efficiency of organic compounds and the toxicity evaluation of microorganism have been studied in dye wastewater treatment using $UV/TiO_2$ and $UV/H_2O_2$ photooxidation system. Sample waters tested in this work were raw dye wastewater and dye wastewater treated in $UV/TiO_2$ and $UV/H_2O_2$ photooxidation system respectively. Total organic carbon(TOC) removal rate was 50% in $UV/TiO_2$ process and 80% in $UV/H_2O_2$ process. It has been investigated with colony counting agar method and paper disk method whether the type of treatment process has affected the microorganism growth. In the raw wastewater, more than four types of microorganisms have survived. But, little of microorganisms were alive at TOC removal rate of 50% in $UV/TiO_2$ system. In contrast to that, two types of microorganisms were found at TOC removal rate of 80% in $UV/H_2O_2$ system.