• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.34 no.2
• /
• pp.75-82
• /
• 2008

In this study, the photocatalysed degradation of safranin-O was investigated using Au colloids. Au metal nanoparticle wasused to eliminate safranin-O fast in solution. Au nanoparticles were prepared reduction method using $Na_2CO_3$ and PVP in aqueous solution. The degradation of safranin-O was examined using a variety of condition such as concentration of Au colloid or Au salt, reaction pH, and reaction time in the presence of UV light and $H_2O_2$. As the concentration of Au colloid increases, the rate of dye degradation increases. The photo-oxidation of the safranin-O was monitored spectrophotometrically. The properties of Au nanoparticles were characterized by UV-Vis spectroscopy. In addition, catalytic capacities of Au nanoparticles were also determined by UV-Vis spectroscopy.

• Journal of the Korea Society of Computer and Information
• /
• v.28 no.2
• /
• pp.99-110
• /
• 2023

In this paper, we propose a system termed ForestLi that can accurately estimate the diameter at breast height (DBH) and tree height using LiDAR point cloud data. The ForestLi system processes LiDAR point cloud data through the following steps: downsampling, outlier removal, ground segmentation, ground height normalization, stem extraction, individual tree segmentation, and DBH and tree height measurement. A commercial system, such as LiDAR360, for processing LiDAR point cloud data requires the user to directly correct errors in lower vegetation and individual tree segmentation. In contrast, the ForestLi system can automatically remove LiDAR point cloud data that correspond to lower vegetation in order to improve the accuracy of estimating DBH and tree height. This enables the ForestLi system to reduce the total processing time as well as enhance the accuracy of accuracy of measuring DBH and tree height compared to the LiDAR360 system. We performed an empirical study to confirm that the ForestLi system outperforms the LiDAR360 system in terms of the total processing time and accuracy of measuring DBH and tree height.

• Journal of the Korean Geotechnical Society
• /
• v.33 no.1
• /
• pp.57-65
• /
• 2017

During a construction of embankment, sub base, or retaining wall backfill, the speedy measurement of water content is necessary. In this study, a test method for field determination of water content of soil by the calcium carbide gas pressure (speedy water content measurement method) was evaluated for its reliability and accuracy. Dry oven and microwave oven methods were also used for water content measurement. In the test, weathered granite and Nakdong River sand in the site and kaolinite were used for water content measurement. The mass of 20, 22, 24, 26, 28, and 30 g of soil was respectively tested for 1, 3, and 5 min. The effect of each sample on water content was compared one another and analyzed. As the mass and testing time increased, the water content increased. The amount of soil was more important factor than testing time for the speedy water content measurement. In order to obtain similar result to that of dry oven method, 3 min of testing time with 24 g of soil was necessary for weathered granite classified as SM and 3 min with 30 g for Nakdong River sand classified as SP. For Nakdong River sand with 20-50% of kaolinite, the water content by speedy measurement increased as the clay content increased.

• Journal of the Korean Society for Library and Information Science
• /
• v.56 no.3
• /
• pp.313-334
• /
• 2022

This study examines the economic use value of Discover, an access service of research papers and a subsystem of the National Open Access Platform (AccessON). Based on previous literature on scholarly communications and in-depth interviews with 14 academic and industrial researchers, the service value of Discover was identified as the value of time savings. Administering a survey with 1,313 researchers, the following empirical data required for estimation were obtained: for an average Korean researcher, s/he publishes 2.84 papers per year and takes 30.13 minutes in searching and using one relevant research paper. Discover was found to save 5.64 minutes per paper, saving a total of 225 minutes and KRW 99,384 per researcher per year. Finally, a total economic value of Discover was estimated as KRW 82 billion for the entire 8-year business period. An additional value of KRW 11.3 billion was estimated with the legalization of mandatory deposit of OA research papers. The study demonstrates a sufficient economic value of the national OA platform project, and positive economic impact of the OA legalization, futher offering important domestic data for future research on economic value of scholarly communications.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.10
• /
• pp.127-136
• /
• 2020

Purpose: This study aimed to establish a basis for application time and cold therapy interval by checking the physiological changes after applying a cold-gel and ice pack, commonly applied to cold therapy, and after passive rewarming. Method: A total of 22 healthy adults used cold-gel packs and ice packs in a Randomized control group repeated measurement study, and passive rewarming was performed for 40 minutes after 30 minutes of cold therapy. After applying to the right axilla, StO₂, SpO₂, peripheral blood flow, skin and body temperature were measured 15 times every 5 minutes. Result: In the cold-gel pack group, StO₂ decreased from 69.43% to 61.06% after 30 minutes application, and in the ice pack group, StO₂ decreased from 67.66% to 64.80% (p <001). In the cold-gel pack group, skin temperature decreased from 33.57℃ to 29.15℃ after 30 minutes application, and in the ice pack group, skin temperature decreased from 32.64℃ to 28.90℃ (p <.001). Only skin temperature recovered completely after 40 minutes of rewarming. There were insignificant differences between the cold-gel pack and ice pack. Conclusion: When applying cold therapy to the axillary, at least 40 minutes for passive rewarming is necessary after 30 minutes of application.

• Journal of Korean Society of Environmental Engineers
• /
• v.39 no.5
• /
• pp.288-302
• /
• 2017

Accurate measurement of benthic nutrient fluxes (BNF) is a prerequisite for evaluating the effect of sediments on nutrient cycle in the surface water. The intact sediment cores were collected in July 2015 at the midstream of Nakdong River. We identified pre-incubation time (6, 12, 24 hr), dissolved oxygen concentration (90, 70, 50% saturation), diffusive boundary layer thickness (0, 0.6-0.8, 1.2-1.4 mm), and incubation temperature (10, 17, 20, $25^{\circ}C$) as the most important control factors, and measured the BNF fluctuation with the variation of these factors using the laboratory sediment core incubation method. Since the chemical composition, redox condition, hydrodynamic regimes and microbial activities at the sediment-water interface were changed as a result of the alteration of control factors, sediment core incubation should be conducted under as close to the natural conditions of study site as possible, in order to produce the results similar to actual values. Relative percentage differences between two replicates were below 20% in most control factors, which showed satisfactory precision for strict compliance with the experimental conditions and procedures. In the further studies, we will compare the results of core incubation with those of in situ measurements to confirm the accuracy of the sediment core incubation method.

• Aerospace Engineering and Technology
• /
• v.4 no.1
• /
• pp.49-56
• /
• 2005

Hot firing performance test of hydrazine decomposition catalyst used for monopropellant thruster of the satellite and the launch vehicle was performed. Test equipment for catalyst test was developed in collaboration with Hanwha Corp., reaction delay time, catalyst activity and granule stability of the catalyst firing performance were measured and analyzed with the equipment. In addition, the current development of prototype catalyst is introduced.

• Korean Journal of Food Science and Technology
• /
• v.40 no.2
• /
• pp.141-145
• /
• 2008

Oxidative stabilities of sesame oil prepared from black sesame flour and white sesame flour, and commercial sesame oil prepared from whole white sesame were compared by measuring oxidation induction periods, peroxide values and electron donating abilities of each oil. Oxidation induction period (12.25 hr) of sesame oil prepared from black sesame flour was longer than those (4.37 and 9.1 hr, respectively) of sesame oil from white sesame flour and commercial sesame oil. Peroxide values of sesame oil prepared from black sesame flour, sesame oil prepared from white sesame flour and commercial sesame oil were 1.3, 18.2 and 1.7 meq/kg oil, respectively. We ascertained that the oxidative stability of sesame oil prepared from black sesame flour was superior than sesame oil from white sesame flour as well as ommercial sesame oil. This was based on the fact that electron donating ability of sesame oil prepared from black sesame flour was 9% higher than that of sesame oil prepared from white sesame flour at the same concentration. The superior oxidative stability of sesame oil prepared from black sesame flour was expected, not only because only it had lignans such as sesamol and sesamolin, but also because of its brownish coloring compounds such as tannin which were not contained in white sesame flour.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.51 no.8
• /
• pp.156-164
• /
• 2014

In a delay line type of a time-to-digital converter implemented in Field Programmable Gate Array, the timing accuracy decreases for a longer carry chain. In this paper, we propose a structure that has a multi-phase clock and a state machine to check metastability; this would reduce the required length of the carry chain with the same time resolution. To reduce the errors caused by the time difference in the four delay lines associated with a four-phase clock, the proposed TDC generates a single input pulse from four phase clocks and uses a single delay line. Moreover, the state machine is designed to find the phase clock that is used to generate the single input pulse and determine the metastable state without a synchronizer. With the measurement range of 1 ms, the measured resolution was 22 ps, and the non-linearity was 25 ps.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.18 no.2
• /
• pp.153-159
• /
• 1989

The experiment was carried out to examine on effect of ultrasonication on the growith of a mungbean while a mungbean is germinated and to measure amino acid content of a mungbean during its germination. Mungbean seeds soaked are divided into three groups; the first group was control group, untreated and naturally germinated. the second was ultrasonic treated group(UTG I), irradiated by ultrasonication for 8, 16 and 24min respectively immediately after soaking. the third was ultrasonic treated group(UTG II), irradiated by ultrasonication after 48hr germinating. The results were as foolows; Fresh weight, moisture, length of mungbean increased as its germination proceeds. while dry weight decreased. Ultrasonication tends to inhibit its germination of mungbean and results in the decrease in weight, length and moisture. Specially ultrasonication had a marked effect on UTG II. The longer the time of ultrasonication was, the more was the growth inhibited. In the control groups, the content of amino acid increased until 72 hours, but after that, it decreased. of the amino acid determined, glutamic acid decreased marekedly in the cotyledons, While the opposite was the case with aspartic acid in the hypocotyls. Comparing with the control groups, UTG I, the content of amino acid decreased. As the ultrasonic treaed time was increased, the concentration of amino acid in hypocotyl cotyledon tended to decreased. UTG II, the content of amino acid was lower than control groups, but higher than UTG I, and the effects of ultrasonication were similar to UTG I.