• Polymer(Korea)
• /
• v.27 no.1
• /
• pp.61-68
• /
• 2003

In this study, we have investigated the preparation of mixed bead and fiber type hybrid ion-exchanger for recovering nickel ion from plating rinse water. There was little dependence of adsorption capacity for nickel ion on the mixing ratio of resin type and fiber type of ion exchangers. However, it increased with increasing the resin content in the mixed bed. It was shown that the data Langmuir and Freundlich's adsorption isotherm model were well fitted to the linear. Affinity between the functional groups in the ion exchanger and nickel ion in the process was confirmed. The pressure drop decreased with increasing the number of stage in the multistage bed, but it increased with increasing the resin content in the mixing bed. The initial breakthrough time in the multistage bed was short due to the increase of number of stage in the continuous process. It was found that the final breakthrough time of the multistage bed was little changed. The breakthrough time decreased with increasing the amount of fibrous ion exchanger in the mixed bed. The maximum adsorption capacities of the mixed and multistage beds were 2.51 meq/g and 2.69 meq/g, respectively. The desorption time for the nickel ion with $1N H_2SO_4$ solution was lower than 10 minutes and the yield of desorption was greater than 98 percent.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2021.05a
• /
• pp.25-26
• /
• 2021

Due to COVID-19, the spread of non-face-to-face culture is increasing the time spent indoors. Accordingly, it is necessary to reduce indoor air pollutants. Also, among building materials, there are paints. As the number of coatings increases, the coating film becomes thick, and there is a risk of cracking and falling off. Therefore, this study is to examine the adsorption properties of indoor air pollutants according to the number of coatings of a paint mixed with powdered activated carbon. In the experimental plan, the addition ratio of powdered activated carbon was selected as 30%, and the number of coatings was selected as primcoating, second coat, and finishing coat, and the concentration of formaldehyde and volatile organic compounds were measured. As a result, as the number of coatings increased, the concentration of formaldehyde and volatile organic compounds tended to decrease. This is considered to be due to the fact that not only the physical adsorption acted by the internal pores of the powdered activated carbon, but also because a lot of powdered activated carbon was present on the painted surface as the coating film was formed. However, since it is judged that there is an error in the concentration due to the inflow of external air as the chamber cover is opened to put the test object in the adsorption test process, it is considered that the experimental method needs to be supplemented.

• Korean Journal of Environment and Ecology
• /
• v.30 no.5
• /
• pp.821-828
• /
• 2016

We examed physiological and flowering response of S. capitata, the endangered plant in Korea, under LED light conditions in plant factory to cultivate artificially for conservation. We cultivated S. capitata and measured its physiological responses and the number of flowers under red, blue, white, red+far-red mixed, red+blue mixed, and red+blue+white mixed light. The results showed that its photosynthetic rate and chlorophyll content were recorded relatively high in red+blue+white and red+blue mixed light respectively. Transpiration rate and stomatal conductance appeared relatively high in the white single light while water use efficiency was no difference. Photochemical efficiency of photochemical photosystem II by minimum and maximum chlorophyll fluorescence was the highest in the red+blue+white mixed light condition than other ones. The number of flowers of S. capitata was at its peak under the red light or red+far-red mixed light. Therefore, we conclude that the most efficient way to grow for flowering of S. capitata is to provide red light or red+far-red mixed light in the plant factory.

• Cartoon and Animation Studies
• /
• s.46
• /
• pp.181-206
• /
• 2017

In the near future, we are expected to live in a Mixed Reality environment where reality and virtuality coexist as today we live using the Internet and smartphones in our daily lives. The relevant content based on the idea of Mixed Reality crystallizing is currently expanding, and it is time for research on it. This study examines the current situation and the development direction of mixed reality contents. Typical mixed reality contents can be classify by wearability. We analyzed HoloLens, a mixed reality wearable device that is worn on a head, which is a example of wearable device. As an example of unwearable device, we also analyzed the Room2Room which is a communication system that combines video with augmented reality-based telepresence avatar. Mixed Reality content will develop in the direction of implementing expanded use of information and more natural realism through the interactive combination of Reality, Virtual Reality, and Augmented Reality. As head-mounted wearable technology develops, Mixed Reality content is expected to become popular by increasing the number of Mixed Reality device users if convenience and price competitiveness are secured. The way of unifying Mixed Reality wearable devices must be established in order to increase convenience, and the environment based on Mixed Reality will be created through diversifying leisure activity content. Telepresence Avatar is expected to develop into Mobile Hologram Avar as Mixed Reality content accessible anywhere and at anytime beyond space limits. Another potential for development of Telepresence Avatar is the combination of Avatar moving on user's thought, Augmented Human technology and Mixed Reality.

• Korean Journal of Weed Science
• /
• v.13 no.2
• /
• pp.151-158
• /
• 1993

This experiment was conducted in order to understand the intra-and the inter-competition of arrowhead, Sagittaria trifolia L., under the conditions of arrowhead monoculture and rice-mixed culture, respectively. In arrowhead monoculture, the infra-specific competition in both shoot length and floral axis number began at 10 plants per $0.5m^2$ and that in leaf number, leaf length, dry shoot weight and formated tuber number did at 5 plants per $0.5m^2$. In the inter-specific competition according to arrowhead density in the constant rice-mixed culture, the plant height and the tiller number of rice decreased at 15 and 5 plants of arrowhead per $0.5m^2$, respectively. The dry top weight and the formated tuber number of arrowhead decreased with increase of arrowhead density. In the inter-competition according to rice plant density in the constant arrowhead-mixed stands, the dry matter weight and the produced tuber number of arrowhead decreased with increase of rice plant density and the plant height and the tiller number of rice also did with that. In the different transplantation time of rice, the growth in arrowhead became less in order of late transplantation>standard one>early one and the plant height and the tiller number of rice became more in order of that by comparing the percentage of growth under the mixed culture to that under the arrowhead monoculture.

• Health Policy and Management
• /
• v.30 no.3
• /
• pp.326-334
• /
• 2020

Background: Korea has gradually expanded the coverage of medical care services in its national health insurance system. On April 1, 2018, it implemented a policy that expanded the coverage for an ultrasonography in the upper abdomen. In this study, we aimed to investigate the effect of the policy on the utilization of the ultrasonography in the upper abdomen in tertiary care hospitals. Methods: Using the dataset of the Health Insurance Review and Assessment Service, we explored changes in the utilization of the ultrasonography in the upper abdomen in tertiary care hospitals from July 1, 2017 to November 30, 2018 through the difference-in-difference (DID) mixed-effects-model method. Facility factor, equipment factor and personnel factors, type of hospital, the total amount of medical care expenses, and geographic region were considered as control variables. Results: On average, the utilization of the ultrasonography in the upper abdomen increased by 228% after the coverage expansion policy. However, the results of DID mixed-effects-model method analysis showed that the utilization increased by 73%. As for the number of beds, the utilization was higher with a group of 844-930, 931-1,217, and 1,218 or greater compared with a group of 843 or fewer, while the utilization of the number of ultrasonic devices was lower with a group of 45-49 compared with a group of 44 or fewer. The utilization decreased with the number of interns and the number of nurse assistants. Besides, relative to Seoul, the utilization was lower in the other metro-cities and provinces. Conclusion: The coverage expansion policy in the national health insurance system increased service utilization among people. Future research needs to investigate the degree to which such coverage expansion policy reduces the unmet medical care needs among the deprived in Korea.

• Journal of fish pathology
• /
• v.11 no.1
• /
• pp.23-27
• /
• 1998

This research was carried out to know the trend in annual occurrence of bacterial disease. The diseased fish were collected from 147 flounder farms of Cheju Island from January, 1991 to December, 1997. Two types of diseases, that is "simple infection" and "mixed infection", were recognized. The simple infections were Vibriosis, Edwardsiellosis Streptococcal infection and Columnaris disease. The mixed infections were caused by a pair of pathogens mentioned above. During the whole period of this study, the highest number of annual occurrence of simple infection was 243 (26.8% of the total) in 1997 and the lowest one was 82 (9.1 %) in 1991. Monthly occurrence of simple infection was the highest number at 132 (14.6% of the total) in August and the lowest one was at 38 (4.2%) in January. Monthly occurrence of the mixed infected disease showed common pattern except November and December. The highest number of annual occurrence of the simple infected disease was 437 (48.2% of the total) in Vibriosis and the lowest one was 22 (2.4%) in Columnaris disease. The highest number of annual occurrence of the simple infected disease was 178 (53.1% of the total) in Vibriosis+Columnaris disease and the lowest one was 28 (8.4%) in Edwardsiellosis+Streptococcal infection.

• The Korean Journal of Food And Nutrition
• /
• v.17 no.1
• /
• pp.8-17
• /
• 2004

The effect of chlorella extract on the growth and acid production of yoghurt starter was investigated in order to prepare the yoghurt added with chlorella extract. The various levels of chlorella extract powder were added to skim milk medium and the medium was fermented by single or mixed culture of 4 types of lactic acid bacteria such as Streptococcus thermophilus, Lactobacillus acidophilus, Lactobacillus casei, and Lactobacillus bulgaricus. The changes in acid production(pH, titratable acidity) and number of viable cells of the medium during fermentation in skim milk added with chlorella extract powder have determined. When chlorella extract powder was added to skim milk medium at the levels of 0.5%, 1.0%, 2.0%, and 3.0%, the addition of 0.5% chlorella extract powder with the single culture of Str. thermophilus, Lac. casei, and Lac. bulgaricus showed the highest number of viable cell counts after 9 hours incubation. And also all single cultures of the yoghurt starter produced the higher amounts of acid with the addition of 0.5% chlorella extract powder. When chlorella extract powder was added to the medium at the levels of 0.25%, 0.5%, 1.0%, and 2.0%, the addition of lower lever(0.25∼0.5%) of chlorella extract powder with the mixed culture of the lactic acid bacteria showed more the acidity of pH and the number of viable cell counts. Among the treatments tested, the addition of 0.25% chlorella extract powder with the mixed culture of Str. thermophilus and Lac. casei produced the highest number of viable cell counts after 12 hours incubation. Therefore it was suggested to manufacture the yoghurt with the addition of 0.25% chlorella extract powder and the inoculation of mixed culture of Str. thermophilus and Lac. casei for on the stimulation of growth of the yoghurt starter.

• KIEE International Transactions on Electrophysics and Applications
• /
• v.4C no.2
• /
• pp.64-67
• /
• 2004

In this paper, to discover the brightness improvement of ZnS:Cu powder electroluminescence (EL), a new structure is proposed in which phosphor and dielectric are mixed between electrodes. Dielectric and phosphor material are BaTiO$_3$ and ZnS:Cu, respectively. The effect of the mixed layer on EL sample is considered the improvement of source efficiency. Although the number of electrons introduced into the phosphor increases only modestly, the high electric field region of phosphor grains increases comparatively in the characteristics of brightness-voltage. Furthermore, the relaxation occurs through leading and trailing edge pairs, which is relatively efficient in characteristics of decay time. With these results, we found that the brightness of newly proposed ZnS:Cu powder electroluminescence was 167.24 cd/$m^2$ at ac voltage of 100V and frequency of 400Hz.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.11 no.2
• /
• pp.152-160
• /
• 2008

In the present paper, a transonic mixed-flow compressor that has relatively lower frontal area than that of centrifugal compressors is discussed, and aerodynamic design as well as performance prediction are performed. Main design constraints are compressor exit Mach number of 0.3 and flow angle of 30degrees at the design point, and maximum overall compressor diameter of 177mm, that is 7.0inch. The mass flow rate of design point and pressure ratio are 1.05kg/s and 5.2:1, respectively. The aerodynamic design results show that the transonic compressor designed with forward-swept inducer and curved diffuser can have the target performance with efficiency of 75% within the given constraints. And the compressor exit flow characteristics are discussed here.