• Particle and aerosol research
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• v.18 no.1
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• pp.9-21
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• 2022

In this study, a novel antiviral coating method for the air filtration system of subway station was investigated. Using dry aerosol coating process, we developed a high-performance antiviral air filter with spark discharger and carbon brush type ionizer. Silver nanoparticles were produced by a spark discharge generation system with ion injection system and were used as antiviral agents coated onto a medium grade air filter. The pressure drop, filtration efficiency, and antiviral ability of the filter against aerosolized MS2 virus particles as a surrogate of SARS-CoV-2 virus were tested with dust contamination. Dust contamination caused the increase of the filtration efficiency and pressure drop, while the antiviral agents (in this study, silver nanoparticles) coating did not have any significant effect on the filtration efficiency and pressure drop. Using these properties, we suggested a novel method to maximize the antiviral performance of the antiviral air filter that was contaminated by dust particles. Moreover theoretical analysis of antiviral ability with dust contamination and re-coated antiviral agents was carried out using a mathematical model to calculate the time-dependent antiviral effect of the filter under actual conditions of subway station. Our model can be used to apply on antiviral air filtration system of subway station for prevention of pandemic diffusion, and predict the life cycle of an antiviral filter.

• International journal of advanced smart convergence
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• v.11 no.4
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• pp.227-239
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• 2022

Purpose: In our study, in order to find lactic acid bacteria (LAB) with multi-drug resistance to antibiotics, we isolated 140 strains from 15 types of kimchi commercially available in Korea and 20 types of Kimchi made at home from January to December in 2016, and investigated their H₂O₂ generating ability and multi-drug resistance to antibiotics. Methods: In order to observe the H₂O₂ generation ability of LAB, we performed the experiment with methods such as Rabe, Hillier, and Kang. To test the antibacterial susceptibility of LAB, we used the disc agar diffusion method using MRS agar (Difco, USA) according to the CLSI and WHO test methods. There are 18 types of antibiotic discs used. Results: Out of the total numbers of 140 strains, 6 strains of Ent. Faecium, 25 strains of L. plantarum, 1 strain of L. rhamnosus, 3 strains of L. sakei, 1 strain of L. acidophilus, 1 strains St. thermophilus, and 7 of unidentified strains generated H₂O₂. The antibiotic susceptibility of Ent. Faecium indicated SXT, OX, NA, and E; and the antibiotic susceptibility of L. plantarum indicated NA; and the antibiotic susceptibility of St. thermophilus indicated NA, CC, RA, CTT, CM, and P ; and the antibiotic susceptibility of L. rhamnosus indicated SXT, VA, NA and CTT; and the antibiotic susceptibility of 6 strains of L. sakei indicated SXT, OX, NOR, NA, CTT and CIP, all indicating antibiotic resistance. In the case of multi-drug resistance to antibiotics for 53 strains of L. antarum, 8-drug resistance was the most common with 25 strains, followed by 7-drug-resistant strains with 18 strains, 9-drug-resistant strains with 4 strains, 6-drug-resistant strains with 3 strains, 5-drug-resistant strains with 2 strains, and 17-drug-resistant strains with 1 strain. In the case of multi-drug resistance to antibiotics for Ent. Faecium 27 strains, 9-drug resistance was most commonly identified as 9 strains, 8-drug resistance was identified as 6 strains, 7- and 11 drug resistances were identified as 4 strains each, and 4- and 6-drug resistances were identified as 1 strain each. Conclusion: Ent. Faecium, L. plantarum, L. rhamnosus, L. sakei, and St. thermophilus, shown to have anantibacterial activity in previous studies on LAB and shown to have and H₂O₂ generating ability, antibiotic resistance and multi-drug resistance in this study, are expected to be able to play an excellent role for long-term inpatients to use as an alternative to antibiotics and to cope with emerging antibiotic resistance.

• Analytical Science and Technology
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• v.22 no.6
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• pp.464-470
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• 2009

For the investigation of the oxidation behavior for titanium metal at various temperatures, titanium specimens were heated for 2 hours in the range of $300{\sim}1000^{\circ}C$, individually. And then X-ray diffraction(XRD), scanning electron microscopy (SEM)/energy dispersive spectroscopy (EDS) and attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopic analyses were carried out. At $300^{\circ}C$, infrared absorption bands on the surface of the titanium specimen were shown in a spectrum by the oxygen uptake of titanium metal(hexagonal). At increased temperature, not only infrared absorption bands but also X-ray diffraction peaks for the titanium oxide were grown and shifted to low wave number ($cm^{-1}$) and angle($^{\circ}$) due to the more oxygen diffusion into titanium metal. At $700^{\circ}C$, $Ti_3O$ (hexagonal phase) was identified by X-ray diffractometer. $TiO_2$ (rutile, tetragonal phase) layer was produced on the surface of the specimen below $1{\mu}m$ in thickness at $600^{\circ}C$, and grown about $2{\mu}m$ at $700^{\circ}C$ and with $110{\mu}m$ in thickness at $1000^{\circ}C$. Above $900^{\circ}C$, (110) plane of the crystal on the surface of rutile-$TiO_2$ layer was grown.

• Investigative Magnetic Resonance Imaging
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• v.17 no.2
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• pp.133-143
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• 2013

Purpose : To evaluate and compare the accuracy of magnetic resonance imaging (MRI) and ultrasound (US) for detection and estimation of invasion depth of colorectal carcinoma (CRC) by correlation with histopathologic findings in vitro, and to find out the best MR pulse sequence for accurate delineation of tumor from surrounding normal tissue. Materials and Methods: Resected specimens of CRC from 45 patients were examined about tumor detectability and invasion depth of US using high frequency (5-17 MHz) linear transducer in a tube filled with normal saline and MRI in a 8-channel quadrate head coil. The institutional review board approved this study and informed consent was waived. MRI with seven pulse sequences of in- and out-of-phases gradient echo T1 weighted images, fast spin echo T2 weighted image and its fat suppression image, fast imaging employing steady-state acquisition (FIESTA) and its fat suppression image, and diffusion weighted image (DWI) were performed. In each case, both imaging findings of MRI and US were evaluated independently for detection and estimation of invasion depth of tumor by consensus of two radiologists and were compared about diagnostic accuracy according to the histopathologic findings as reference standard. Seven MR pulse sequences were evaluated on the point of accurate delineation of tumor from surrounding normal tissue in each specimen. Results: In specimens of CRC, both imaging modalities of MRI (91.1%) and US (86.7%) showed relatively high diagnostic accuracy to detect tumor and evaluate invasion depth of tumor. In early CRC, diagnostic accuracy of US was 87.5% and that of MRI was 75.0%. There was no statistically significant difference between two imaging modalities (p > 0.05). The best pulse sequence among seven MR sequences for accurate delineation of tumor from surrounding normal tissue in each specimen of CRC was fast spin echo T2 weighted image. Conclusion: MRI and US show relatively high diagnostic accuracy to detect tumor and evaluate invasion depth of resected specimen of CRC. The most excellent pulse sequence of MRI for accurate delineation of tumor from surrounding normal tissue in CRC is fast spin echo T2 weighted image.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.618-625
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• 2018

With the passing of time, exposed concrete structures are affected by a range of environmental, chemical, and physical factors. These factors seep into the concrete and have a deleterious influence compared to the initial performance. The importance of identifying and preventing further performance degradation due to the occurrence of deterioration has been greatly emphasized. In recent years, evaluations of the target life have attracted increasing interest. During the freezing-melting effect, a part of the concrete undergoes swelling and shrinking repeatedly. At these times, chloride ions present in seawater penetrate into the concrete, and accelerate the deterioration due to the corrosion of reinforced bars in the concrete structures. For that reason, concrete structures located onshore with a freezing-melting effect are more prone to this type of deterioration than inland structures. The aim of this study was to develop a high performance mortar mixed with a mineral admixture for the durability properties of concrete structures near sea water. In addition, experimental studies were carried out on the strength and durability of mortar. The mixing ratio of the silica fume and meta kaolin was 3, 7 and 10 %, respectively. Furthermore, the ultra-fine fly ash was mixed at 5, 10, 15, and 20%. The mortar specimens prepared by mixing the admixtures were subjected to a static strength test on the 1st and 28th days of age and degradation acceleration tests, such as the chloride ion penetration resistance test, sulfuric acid resistance test, and salt resistant test, were carried out at 28 days of age. The chloride diffusion coefficient was calculated from a series of rapid chloride penetration tests, and used to estimate the life time against corrosion due to chloride ion penetration according to the KCI, ACI, and FIB codes. The life time of mortar with 10% meta kaolin was the longest with a service life of approximately 470 years according to the KCI code.

• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.1
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• pp.9-18
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• 2012

Annual power consumption of our country is positioned in the upper percentile in the world, and because the proportion of fossil power generation is high, which ranks the 10th $CO_2$ emission country. In this regard, government has established and is implementing the National Energy Basic Plan to realize to get out of fossilization in energy supply while focusing on securing the technology for renewable energy as well as its commercialization in order to reduce greenhouse gas. Resource recovery technology for deep seawater thermal energy which is one of renewable energies is newly getting attention domestically as well as in overseas for securing resources and environmental improvement as a core technology for multilateral use of marine resources for low carbon and green growth. Economic feasibility analysis was conducted for the research and development as follows on the use of ocean thermal energy conversion and seawater air conditioning. First, in the case of power generation using deep seawater and warm discharge water from ocean thermal energy conversion plant of 1MW level, it is judged that the economic feasibility is insufficient but the feasibility will be significantly improved if we consider not only power generation but also drinking water and certified emission reduction by developing the power plant to the size for commercialization. Second, the economic feasibility for the use of deep seawater as air conditioning for the power plant of 1,000RT level turned out to be very good. Especially, when we consider certified emission reduction, it will be possible to secure sufficient economic feasibility. When we use it in connection with ocean thermal energy conversion, water conversion and agricultural and fishery use, it is judged that economic ripple effect will be significant and therefore it will be necessary to conduct research and development for early commercialization, distribution and diffusion of deep seawater energy.

• Journal of the Korean Geographical Society
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• v.29 no.2
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• pp.117-136
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• 1994

Contemporary global space economy is so dynamic that any one specific structural force can not explain the whole dynamic processes or trajectories of spatial industrial development. The major purpose of this paper is extending the traditional notion of industrial districts to functioning and development of new industrial districts with relation to the development of high technology industries. Several dynamic forces, which are dominated in new industrial districts in the modern space economy, are incorporated in the formation and dynamic aspects of new industrial districts. Even though key forces governing Marshallian industrial district are localization of small firms, division of labor between firms, constructive cooperation, and industrial atmosphere, Marshall points out a possibility of growing importance of large firms and non-local networks in the districts with changes of external environments. Some of Italian industrial districts can be regarded as Marshallian industrial districts in broader context, but the role of local authorities or institutions and local embeddedness seem to be more important in the Italian industrial districts. More critical implication form the review of Marshallian industrial districts and Italian industrial districts is that the industrial districts are not a static concept but a dynamic one: small firm based industrial districts can be regarded as only a specific feature evolved over time. Dynamic aspects of new industrial districts are resulting from coexistence of contrasting forces governing the functioning and formation of the districts in contemporary global space economy. The contrasting forces governing new industrial districts are coexistence of flexible and mass production systems, local and global networks, local and non-local embeddedness, and small and large firms. Because of these coexistence of contrasting forces, there are various types of new industrial districts. Nine types of industrial districts are identified based on local/non-local networks and intensity of networks in both suppliers and customers linkages. The different types of new industrial districts are described by differences in production systems, embeddedness, governance, cooperation and competition, and institutional factors. Out of nine types of industrial districts, four types - Marshallian; suppliers hub and spoke; customers hub and spoke; and satellite - are regarded as distinctive new industrial districts and four additional types - advanced hub and spoke types (suppliers and customers) and mature satellites (suppliers and customers) - can be evolved from the distinctive types and may be regarded as hybrid types. The last one - pioneering high technology industrial district - can be developed from the advanced hub and spoke types and this type is a most advanced modern industrial district in the era of globalization and high technology. The dynamic aspects of the districts are related with the coexistence of the contrasting forces in the contemporary global space economy. However, the development trajectory is not a natural one and not all the industrial districts can develop to the other hybrid types. Traditionally, localization of industries was developed by historical chances. In the process of high technology industrial development in contemporary global space economy, however, policy and strategies are critical for the formation and evolution of new industrial districts. It needs formation of supportive tissues of institutions for evolution of dyamic pattern of high technology related new industrial districts. Some of the original distinctive types of new industrial districts can not follow the path or trajectory suggested in this paper and may be declined without advancing, if there is no formation of supportive social structure or policy. Provision of information infrastructure and diffusion of an entrepreneurship through the positive supports of local government, public institutions, universities, trade associations and industry associations are important for the evolution of the dynamic new industrial districts. Reduction of sunk costs through the supports for training and retraining of skilled labor, the formation of flexible labor markets, and the establishment of cheap and available telecommunication networks is also regarded as a significant strategies for dynamic progress of new industrial districts in the era of high technology industrial development. In addition, development of intensive international networks in production, technology and information is important policy issue for formation and evolution of the new industrial districts which are related with high technology industrial development.

• The Journal of Engineering Geology
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• v.18 no.4
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• pp.471-482
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• 2008

This study was carried out to investigate the contamination characteristics of surface water, soil water and groundwater around and in antimony waste landfill site in Wonsung-ri, Yeonki-kun, Chungnam. The waste disposed in the study was excavated and transported to the other site in several years ago. For this study, we collected 35 water samples including groundwater, soil water and surface in the study site and also collected 2 groundwater samples from a comparison site. The data of chemical analysis of soil water samples show the antimony concentration of $48.75{\sim}74.81\;ppb$, which is much higher than groundwater in a comparison site and is highly excess than regulation level for a drinking water of some advanced countries. A relatively high antimony concentration was detected in three stream water samples nearby landfill site and two groundwater samples. Fe and Mn contents in soil water and stream water were measured as maxium 6.5 mg/L and 7.3 mg/L, respectively. Although other heavy metals of water samples in the study site are higher concentration than water sample of comparison site, their absolute levels are lower than regulation level for a drinking water. The chemical data of water samples are plotted widely from Ca - $HCO_3$ type to Ca - ($Cl +SO_4+NO_3$) type. Some groundwater show high contents of potassium and nitrate, which would come from fertilizer and sewage. Conclusively, some heavy metals including antimony have been still remained under the soil surface of the landfill site in the past. These metals have leaked out into nearby stream and groundwater system, and threaten the ecology, crops and the health of residents in this site. Therefore, the government have to prepare the strategy to prevent the diffusion of heavy metals into aquatic environment and have to process the reclamation work for contaminated site. It is also necessary to make a regulation level of the antimony concentration for a drinking water and soil environment in Korea.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.8 no.4
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• pp.392-400
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• 2003

We used an oxygen microelectrode to measure the vertical profiles of oxygen concentration in sediments located near point sources of organic matter. The measurements were carried out between 13th and 17th May, 2003, in semi-closed bay and coastal sediments in the central part of the South Sea. The measured oxygen penetration depths were extremely shallow and ranged from 1.30 to 3.80 mm. This suggested that the oxidation and reduction reactions in the early diagenesis should be studied at the mm depth scale. In order to estimate the oxygen consumption rate, we applied the one-dimension diffusion-reaction model to vertical profiles of oxygen near the sediment/water interface. Oxygen consumption rates were estimated to be between 10.8 and 27.6 mmol O$_2$ m$\^$-2/ day$\^$-1/(average: 19.1 mmol O$_2$ m$\^$-2/ day$\^$-1/). These rates showed a positive correlation with the organic carbon of the sediments. The corresponding benthic organic carbon oxidation rates calculated using an modified Redfield ratio (170/110) at the sediment/water interface were in the range of 89.5-228.1 mg C m$\^$-2/ day$\^$-1/(average: 158.0 mg C m$\^$-2/ day$\^$-1/). We suggest that these results are maximum values at the presents situation in the bay because the sampling sites were located near point sources of organic materials. This study will need to be carried out at many coastal sites and throughout the seasons to allow an understanding of the mechanisms of eutrophication e.g. the spatial distribution of oxygen consumption within the oxic zone and hypoxic conditions in the coastal sea.

• Korean Journal of Heritage: History & Science
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• v.44 no.4
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• pp.18-41
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• 2011

The Safeguarding of Intangible Cultural Heritage in Korea has begun since1962 when the Cultural Properties Protection Act was established. Korean ICH Safeguarding system is initially derived from Cultural Properties Protection Act in Japan. Japan has started Important ICH Designation System in 1954 to concede the skills and artistic talents holders, thus it could implement the multilateral system management for adopting different ICH protection systems such as Important Intangible Folklore Properties, Selection and Preservation Techniques, and Documenting Records. However, Korea has solely adopted Important ICH Designation System since Cultural Properties Protection Act was introduced. Korean ICH Safeguarding System represented by the Certification System of ICH Skill Holders is to ensure skills and artistic holders who perform the elements of Intangible Cultural Heritage, and manage the safeguarding of intangible cultural heritage in order to let the skills and artistic holders instruct inheritors. As a result, it could build up the internal foundation for the diffusion of inheritors and established the related organizations. However, the inheritor-centered protection system has caused many problems as it is being lasted for more than fifty years. Fragmented designation measures, the cultural power of skill holders, and the research and evaluation methods have pointed out the difficulties of safeguarding and preservation measures of ICH. Moreover,the legitimacy of safeguarding system related in the authenticity of transmission in ICH has emerged to review the safeguarding system of ICH with diverse viewpoints. Therefore, this paper will review the implementation process and achievement of ICH safeguarding system to examine the problem and causes of the safeguarding system. The conference records of Cultural Property Association and articles of cultural properties policies directors, Cultural Property Association members, and professional experts are being used for the initial materials of this paper, and it is examined for the contents of designation system of Important Cultural Heritage, rather than overall cases. Thus such problems the limitation of expansion in ICH lists as inheritor-centered designation system, hierarchical and exclusive transmission system, inappropriate concept of archetype as the principle of ICH transmission are derived from the root of Important ICH designation system. Thus this paper demonstrates that this system must be revised for the expansion of ICH safeguarding system in Korea and points out multilateral protection system should be established as well as Certification System of Important ICH skill holders.