• Biomedical Science Letters
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• v.9 no.3
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• pp.139-144
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• 2003

Since water borne infection causes acute diseases and results in spread of diseases by secondary infection, the prevention is very important. Therefore, it is necessary to have a method that is rapid and effective to monitor pathogenic bacteria in drinking water. In this study, we employed a systematic method, Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) analysis, to develop an effective monitoring system for possible bacterial contaminants in drinking water. For this purpose, PCR primers were derived from 992 bp region of the 16s rRNA gene that is highly conserved through the different species of prokaryotes. To test whether the PCR primers designed are indeed useful for detecting all the possible microbial contaminants in the water, the primers were used to amplify 16s rRNA regions of different microbial water-borne pathogens such as E. coli, Salmonella, Yersinia, Listeria, and Staphylococcus. As expected, all of tested microorganisms amplified expected size of PCR products indicating designed PCR primers for 16s rRNA indeed can be useful to amplify all different microbial water-borne pathogens in the water. Furthermore, to test whether these 16s rRNA based PCR primers can detect bacterial populations present in the water, water samples taken from diverse sources, such as river, tap, and sewage, were used for amplification. PCR products were for then subjected for cloning into a T-vector to generate a library containing 16s rRNA sequences from various bacteria. With cloned PCR products, RFLP analysis was done using PCR products digested with restriction enzyme such as Hae III to obtain species-specific RFLP profiles. After PCR-RFLP, the bacterial clones which showed the same RFLP profiles were regarded as the same ones, and the clones which showed distinctive RFLP profiles were subsequently subjected for sequence analysis for species identification. By this PCR-RFLP analysis, we were able to reveal diverse populations of bacteria living in water. In brief, in unsterilized natural river water, over 60 different species of bacteria were found. On the other hand, no PCR products were detected in drinking tap-water. The results from this study clearly indicate that the PCR-RFLP-sequence analysis can be a useful method for monitoring diverse, perhaps pathogenic bacteria contaminated in water in a rapid fashion.

• The Journal of the Korea Contents Association
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• v.15 no.6
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• pp.547-564
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• 2015

These days, corporations which are eager to improve employees' performance and focus on consistent management highlight core values and core value education. The purpose of this research is to present a case study on the core value education administered by large corporations, to analyze and compare them, and finally present implications for the core value education. For this purpose, 5 large corporations in Korea have been selected. The data was collected from secondary sources and through interviews with the present and former educators in charge of core value education of those corporations. This study found that 5 large corporations commonly considered their core value as a main source of competitiveness and focused on the systematic core value education. But at the same time, each of them chose its own way to educate employees. Their strategies, management methods, and connection to the personnel policy differed in details. 5 large corporations were shown that they reached the level of understanding and empathy, but only 2 large corporations were interviewed as to reach the level of practice. To make core value internalized in the employees' thoughts and acts, it is required to strengthen alliance between core values and work which encourages worker's real practice in their daily lives, to have a diverse curriculum according to the work categories and regions, and to emphasize the connection with other policies especially evaluation policy.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.3
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• pp.252-262
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• 2014

Sorghum seed is traditionally used as secondary food sources in addition to rice in Korea. While the hypoglycemia regulating phytochemicals have been found in sorghum seed, peptides related with hypoglycemia never been studied before. To obtain the peptide characteristics and the specifically high-expressed peptides in hypoglycemic sorghum seed, peptide profiles of seven hypoglycemic and five non-hypoglycemic sorghum lines bred in RDA were determined using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS). The twelve sorghum lines exhibited 104 peptides on CM10 protein chip array (weak cation exchange) and 95 peptides on Q10 (weak cation exchange) in the molecular mass range from 2,000 to 20,000 Da. Heat map via supervised hierarchical clustering of the significantly different peptides (p < 0.01) in peak intensity among the 12 lines effectively revealed the specifically upregulated peptides in each line and distinguished between 7 hypoglycemic and 5 non-hypoglycemic lines. Through the comparison with hypoglycemic and non-hypoglycemic lines, 10 peptides including 2231.6, 2845.4, 2907.9, 3063.5, 3132.6, 3520.8, 4078.8, 5066.2, 5296.5, 5375.5 Da were specifically high-expressed in hypoglycemic lines at p < 0.00001. This study characterized seed peptides of 12 sorghums and found ten peptides highly expressed for hypoglycemic sorghum lines, which could be used as peptide biomarkers for identification of hypoglycemic sorghum.

• Journal of Korean Society for Atmospheric Environment
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• v.34 no.1
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• pp.1-15
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• 2018

Nation-wide systematic and comprehensive measurements of air quality criteria species have been made over 340 sites currently in Korea since 1990. Using these data, temporal and spatial trends of $SO_2$, $PM_{10}$, $NO_2$, $O_3$, CO and $O_x(NO_2+O_3)$ were analyzed to characterize and evaluate implementing efficiency of air quality policy and regulations. Due to strict and effective policy to use cleaner fuels in late 1980s and 1990s, the primary pollutants, such as $SO_2$, CO, and $PM_{10}$ decreased sharply by early 2000s in all parts of Korea. After this period, their concentrations declined with much lower rates in most parts of Korea. In addition, isolated but noticeable numbers of places, especially in major ports, newly developing towns and industrial parks, sustained high levels or even showed further degradation. Despite series of emission control strategies were enforced since early 1990s, $NO_2$ concentrations haven't changed much till 2005, due to significant increase in number of automobiles. Nevertheless, we confirmed that the staggering levels of $NO_2$ and $PM_{10}$ improved evidently after 2005, especially in Seoul Metropolitan Area (SMA), where enhanced regulations for $NO_2$ and $PM_{10}$ emissions was imposed to automobiles and large emission sources. However, their decreasing trends were much lessened in recent years again as current air quality improvement strategies has been challenged to revise further. In contrast to these primary species, annual $O_3$, which is secondary product from $NO_2$ and volatile organic compounds (VOCs), has increased consistently with about 0.6 ppbv per year in every urban part of Korea, while yearly average of daily maximum 8-hour $O_3$ in summer season had a much higher rate of 1.2 ppbv per year. Increase of $O_3$ can be explained mainly by reductions of NO emission. Rising background $O_3$ in the Northeast Asia and increasing oxidizing capacity by changing photochemistry were likely causes of observed $O_3$ increase. The future air quality policy should consider more effective ways to lower alarming level of $O_3$ and $PM_{10}$.

• Journal of the Korean Regional Science Association
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• v.15 no.2
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• pp.131-153
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• 1999

Since 1980's there have been two trends that obviously developed in the would -- economics globalization and urban internationalization. China, with is reform and opening-up policy and rapid economic growth, keeps pace with these two trends. The term "International City" has no putative standard or definition. If we make an analogue of urban functional hierarchy in the world with a pyramid, the International Citiesa are the few elites on its top. The highest level international cities can be called "World City" or "Global City". In today's new international division of labor, they are diversified leading cities with control capacity on a world scale, like New York, London, and Tokyo. The secondary international cities are either diversified cities with influence and regulative functions on multinational scale or specialized cities on politics, economics, culture, or other aspects with worldwide impact. Judged by different criteria, there is no city that is qualified as International City with the exception of Hong Kong, which was returned to the P.R. of China in 1997. Nevertheless, Some favorable conditions for the development of the international city still exist in China. This country is already the sixth largest economic entity in the world, and the second largest economic entity in the world, and the second largest one if GNP estimated by ppp. Furthermore its import and export value make up for 40% of its GNP, indicating that China is repidly merging into global economy. In this 1, 2 billion-population country, the difference of economic levels between urban and rural, coastal and inland regions is so big that a few metropolises in the coastal region have the possibilities and potentials to develop into international cities regardless of rather low GNP per capita of the whole country. This article will focus on analysis from several perspectives, such as the proportion of foreign trade values in GDP, the proportion of imports and exports by foreign funded enterprises in total foreign trade value; distribution of the 500 largest foreign-funded enterprises; distribution of the 500 enterprises with largest import and export values; distrigbution of foreign computer and telecom companies with offices in China; the number of outward flights per week and the international tourists; the value of foreign capital used in cities and so on. From this analysis, it is predicted that Chinese international cities will surely emergy from the eastern coastal regions and they must be the core cities of metropolitan interlocking regions that have been formed or in the process of forming. Those international cities will arise from south to north in turn : Hong Kong-Guangzhu, Shanghai, Beijing-Tianjin, and perhaps the last one is Dalian-Shenyang. The other side of this issue is that there is a long way for the coming international cities in China except Hong Kong. At least China and these core cities must continually devote to (1) improve the regional composition of foreign capital sources. (2) improve the composition of export commodities. (3) improve the investment environment (including hard and soft environment) to attract more transnational corporations to settle. (4) deepen the reform of state-owned enterprises and establish Chinese own transnational corporations to enter the world market.ons to enter the world market.

• Korean Journal of Optics and Photonics
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• v.28 no.4
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• pp.166-171
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• 2017

Hydrogen gas is a green energy sources because it features no emission of pollutants during combustion. But hydrogen gas is very dangerous, being flammable and very explosive. Hydrogen gas detection is very important for the safety of a nuclear power plant. Hydrogen gas is generated by oxidation of nuclear fuel cladding during a critical accident, and leads to serious secondary damage in the containment building. This paper discusses the development of a Raman lidar system for remote detection and measurement of hydrogen gas. A small, portable Raman lidar system was designed, and a measurement algorithm was developed to quantitatively measure hydrogen gas concentration. To verify the capability of measuring hydrogen gas with the developed Raman lidar system, experiments were carried out under daytime outdoor conditions by using a gas chamber that can adjust the hydrogen gas density. As results, our Raman lidar system is able to measure a minimum density of 0.67 vol. % hydrogen gas at a distance of 20 m.

• Geophysics and Geophysical Exploration
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• v.12 no.4
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• pp.361-366
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• 2009

Layered-earth Green's functions in electormagnetic (EM) surveys play a key role in modeling the response of exploration targets. They are computed through the Hankel transforms of analytic kernels. Computational precision depends upon the choice of algebraically equivalent forms by which these kemels are expressed. Since three-dimensional (3D) modeling can require a huge number of Green's function evaluations, total computational time can be influenced by computational time for the Hankel transform evaluations. Linear digital filters have proven to be a fast and accurate method of computing these Hankel transforms. In EM modeling for 3D inversion, electric fields are generally evaluated by the secondary field formulation to avoid the singularity problem. In this study, three components of electric fields for five different sources on the surface of homogeneous half-space were derived as primary field solutions. Moreover, reflection coefficients in TE and TM modes were produced to calculate EM responses accurately for a two-layered model having a sea layer. Accurate primary fields should substantially improve accuracy and decrease computation times for Green's function-based problems like MT problems and marine EM surveys.

• KSBB Journal
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• v.9 no.3
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• pp.246-252
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• 1994

Enzyme-catalyzed polycondensatlon reaction of aliphatic polyesters with several repeating units was studied using the biocatalytic activities of lipases from different sources. Porcine pancreatic lipase (PPL) was found to be best in utilizing bls(2,2,2-trichloroethyl) glutarate and 1,4-butanediol as substrafes. The reaction was also catalyzed to some extent by the lipases from Humicola lanuginos and Psudomonas sp. In the series of short-chain diols(C2-C4), bis(2,2,2-trichloroethyl) glutarate was iransesterified fastest with 1,4-butanediol and for the long-chain diols (PEG-300-PEG-1000), the reaction was fastest with PEG-400. With PEGs, only monoesterification product was obtained. PPL functioned well in relatively hydrophilic organic solvents such as tetrahydrofuran(THF), ether and acetonitrile. The reaction rate was accelerated as the reaction temperature was raised from $20^{\circ}C$ to $60^{\circ}C$ while Mn values of the reaction products were not affected by the reaction temperature. End group analysis by NMR showed that Mn values of the polymer were in the range of 1500-4000 daltons.

• Current Optics and Photonics
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• v.2 no.3
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• pp.269-279
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• 2018

We are currently investigating the feasibility of a 1.6 m telescope with a laser-guide star adaptive optics (AO) system. The telescope, if successfully commissioned, would be the first dedicated adaptive optics observatory in South Korea. The 1.6 m telescope is an f/13.6 Cassegrain telescope with a focal length of 21.7 m. This paper first reviews atmospheric seeing conditions measured over a year in 2014~2015 at the Bohyun Observatory, South Korea, which corresponds to an area from 11.6 to 21.6 cm within 95% probability with regard to the Fried parameter of 880 nm at a telescope pupil plane. We then derive principal seeing conditions such as the Fried parameter and Greenwood frequency for eight astronomical spectral bands (V/R/I/J/H/K/L/M centered at 0.55, 0.64, 0.79, 1.22, 1.65, 2.20, 3.55, and $4.77{\mu}m$). Then we propose an AO system with a laser guide star for the 1.6 m telescope based on the seeing conditions. The proposed AO system consists of a fast tip/tilt secondary mirror, a $17{\times}17$ deformable mirror, a $16{\times}16$ Shack-Hartmann sensor, and a sodium laser guide star (589.2 nm). The high order AO system is close-looped with 2 KHz sampling frequency while the tip/tilt mirror is independently close-looped with 63 Hz sampling frequency. The AO system has three operational concepts: 1) bright target observation with its own wavefront sensing, 2) less bright star observation with wavefront sensing from another bright natural guide star (NGS), and 3) faint target observation with tip/tilt sensing from a bright natural guide star and wavefront sensing from a laser guide star. We name these three concepts 'None', 'NGS only', and 'LGS + NGS', respectively. Following a thorough investigation into the error sources of the AO system, we predict the root mean square (RMS) wavefront error of the system and its corresponding Strehl ratio over nine analysis cases over the worst ($2{\sigma}$) seeing conditions. From the analysis, we expect Strehl ratio >0.3 in most seeing conditions with guide stars.

• Journal of Korean Home Economics Education Association
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• v.32 no.1
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• pp.1-14
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• 2020

The main purpose of this research was to develop upcycled DIY kits made from subway billboard material to make living products. This study was conducted based on the following four stages of design process: research and analyses, DIY kits' design direction establishment, completion of DIY kits, and implementation and evaluation. Through this study, we developed DIY kits for pouches, tissue cases and pencil cases. In the implementation and evaluating stage, we chose to make pouches because it includes zipper attachment process. Implementation was conducted by recruiting four high school students and four female adults. As a result, we found the following: First, the participants were able to make pouches in less than an hour. Second, pouch making has a moderate degree of difficulty. Third, video instructions should be slowed down. Forth, materials need to be improved. Fifth, environmental awareness was improved by using unfamiliar subway billboard materials. The upcycled DIY kits, developed as a result of this study, can be used as eco-friendly education sources for secondary school students as well as for adults' healing hobby.