• The Korea Beekeeping Bulletin
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• s.302
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• pp.27-28
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• 2005

• Journal of the Korean Chemical Society
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• v.52 no.1
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• pp.16-22
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• 2008

on-line system for preconcentration and separation of lead(II) is presented. The method is based on the complex formation of Pb(II) with adsorbed Methyl thymol blue on activated carbon. The conditions of preparing the solid phase reagent and of quantitative recovery of Pb(II) from diluted solutions, such as acidity of aqueous phase, solid phase capacity, and flow variables were studied as well as effect of potential interfering ions. After preconcentration step, the metal ions are eluted automatically by 5 ml of 0.5 M HNO3 solution and the lead ions content was determined by flame atomic absorption spectrometry. Under the optimum conditions, the lead ions in aqueous samples were separated and preconcentrated about 1000-fold by the column. The detection limit was 0.001 g mL-1. Lead has been determined in river and tap water samples, with recovery of 98 to 102%.

• Journal of Digital Convergence
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• v.16 no.10
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• pp.409-414
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• 2018

In China, the usage of smart speaker is continuously increasing. In this study, it is aimed to research on the user experience of the Chinese smart speaker. Therefore, we did literature research followed with theoretical background of smart speaker, and did case study of worldwide popular smart speaker brands. On this basis, we conducted in-depth interview with 8 users who have experienced with the top-selling Chinese smart speaker product "Tmall Genie" and "Mi AI speaker". The interview is based on 7 principles named Honeycomb model, which created by Peter Morville. As a result, users' discomfort was found in the functional part and the usability part of the smart speaker. Furthermore, the users were highly unsatisfied with the smart speaker in the credibility part. Accordingly, Chinese smart speaker should consider the user experience aspects to complement functional and usability parts for user.

• Journal of the Korean Chemical Society
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• v.55 no.1
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• pp.46-49
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• 2011

A highly sensitive and selective extraction-spectrophotometric method has been developed for determination of trace amounts of cimetidine. This method is based on the extraction of cimetidine as an ion pair with bromothymol blue (BTB) into chloroform and measuring its absorbance at 417 nm. The effect of different variables such as pH, concentration of BTB, volume of chloroform and shaking time was investigated. The effect of interfering ions on the extraction was also studied. The calibration curve was linear in the range of 0.25-8 ${\mu}gmL^{-1}$ with correlation coefficient of 0.9997. The detection limit based on 3Sb was 0.14 ${\mu}gmL^{-1}$ and relative standard deviation for 10 replicated measurements of 1.0 and 4.0 ${\mu}gmL^{-1}$ of cimetidine was 3.2 and 1.49%, respectively. The proposed method was applied to the determination of cimetidine in pharmaceutical samples with good recoveries.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.681-693
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• 2019

Multi-use ophthalmic solutions are used many times after opening; therefore, there is a high possibility of decreased quality during use. This study was conducted to determine the recommended use period of multi-use ophthalmic solutions based on evaluation of the stability by comparing stability evaluation regulations of the USA, EU and Korea We selected four types of multi-use ophthalmic solutions (Olopatadine (Olo), Fluorometholone (Flu), Dorzolamide (Dor), Timolol (Timol)) that are frequently marketed in Korea and evaluated their stability during storage according to the actual usage method after opening. The Olo had a decrease in assay and preservative content at 2 months after opening, while Flu showed a significant difference from day 28 after opening. For Dor, significant differences were observed from day 14 after opening in the assay and impurity test item and Timol showed a significant difference from day 28 after opening. Based on the results of the stability test Olo and Flu should only be used within 28 days of opening, while Dor and Timol should be used within 14 days of opening. Therefore, we suggest that regulations system related use periods of multi-use ophthalmic solutions designed as aseptic preparations should be improved based on the results of stability tests after opening.

• Conservation Science in Museum
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• v.2
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• pp.9-17
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• 2000

This is a case study of conservation treatment of the textiles and costumes excavated from Soonchun Park's tomb in Eumsung, North Chungcheong province. When excavated, the objects were found fairly wet and badly smelled since they decayed in wooden coffin. They were wet-treated with deionized water to remove dirt and dried at room temperature, during which the objects were blocked and flattened to keep them in shape. Silk crepeline was under-layed and stitched to the damaged areas with silk-hair threads. Each costume was individually stored in a tray made of paulownia wood and flat textiles were rolled up in paper cylinders with 6 and 10 cm in diameter. Thymol was used to prevent microorganisms.

• Journal of Bio-Environment Control
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• v.18 no.4
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• pp.468-474
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• 2009

Thyme leaves of aerial part in 5 domestic species was extracted by several solvens, and chemical composition of extracts was analyzed by GC-MS to determine the effective solvent for phenol compound extracts. Total phenol contents containing thymol and carvacrol according to methanol extracts of Ulleung island, Jeju middle mountain, Kyeonggido, Jeju alpine species, and Gangwondo were 92.21, 84.92, 77.43, 74.16, and 73.51%, while them of ethanol extracts of Gangwondo, Jeju middle mountain, Kyeonggido, Ulleung island, and Jeju alpine species were in the order of and their contents were 93.64, 93.62, 90.74, 89.52, and 72.65%, separately. Hexane extracts of Gangwondo and Ulleung island thyme were almost composed by phenol contents containing thymol for 100 and 95.71%.

• Journal of Bio-Environment Control
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• v.9 no.2
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• pp.79-84
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• 2000

The growth and quality differences between common thyme(Thymus vulgaris L.) and lemon thym (Thymus$\times$citriodorus) were investigated. They were grown in a hydroponics culture system (DFT) with a nutrient solution developed by the European Vegetable R&D Center in Belgium. Nutrient solution ionic strength used were 1.2, 2.4, 4.8 and 7.2 mS.cm-1. The dry matter of two thymes were increased with increasing ionic strength, while shoot length, root length and fresh weight were decreased. Chlorophyll content was higher in lemon thyme, while vitamin C content and essential oil content were higher in common thyme. The essential oil content showed a similar trend as those of growth. The main compostion of essential oil were thymol and carvacrol in common thyme, and geraniol and $\alpha$-citral in lemon thyme. The highest content of these compounds was obtained in 1.2mS.cm-1 treatment. Consequently, the ionic strength of 1.2mS.cm-1 was suitable for the production of quality thymes.

• Analytical Science and Technology
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• v.34 no.3
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• pp.128-133
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• 2021

During titration, several chemical reactions result in changes not only in the potential of chemicals, but also in the colors of the indicator. In a potentiometric titration, a titration curve is obtained by measuring the abrupt change in the potential at the endpoint. Generally, acid-base titration is performed by observing the color change caused by an indicator to determine the endpoint. The method of determining the endpoint by measuring the potential difference has been well established and commercialized; however, the devices that can obtain the endpoint by observing the color change are limited. Consequently, in this study, a simple and precise spectral endpoint detector was manufactured using a drop-counter comprising an infrared emitter and a phototransistor, a white light LED as the light source and photodetector, and an analog-to-digital converter (Arduino). Spectrator, a new named, showed excellent results in terms of the reproducibility of acid-base titration using thymol blue as an indicator. Herein, we present the results of the Spectrator-manufacturing process as well as the experimental results.