• Journal of the Korean Society of Marine Environment & Safety
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• 제24권5호
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• pp.628-636
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• 2018

Because large buoys are mainly made of steel, they are heavy and vulnerable to corrosion by sea water. This makes buoy installation and maintenance difficult. Moreover, vessel collision accidents with buoys and damage to vessels due to the material of buoys (e.g., steel) are reported every year. Recently, light buoys adopting eco-friendly and lightweight materials have come into the spotlight in order to solve the previously-mentioned problems. In Korea, a new lightweight buoy with a 7-Nautical Mile lantern adopting expanded polypropylene (EPP) and aluminum to create a buoyant body and tower structure, respectively, was developed in 2017. When these light buoys are operated in the ocean, the visibility and angle of light from the lantern installed on the light buoys changes, which may cause them to function improperly. Therefore, research on the performance of light buoys is needed since the weight distribution and motion characteristics of these new buoys differ from conventional models. In this study, stability estimation and motion analyses for newly-developed buoys under various environmental conditions considering a mooring line were carried out using ANSYS AQWA. Numerical simulations for the estimation of wind and current loads were performed using commercial CFD software, Siemens STAR-CCM+, to increase the accuracy of motion analysis. By comparing the estimated maximum significant motions of the light buoys, it was found that waves and currents were more influential in the motion of the buoys. And, the estimated motions of the buoys became larger as the sea state became worser, which might be the reason that the peak frequencies of the wave spectra got closer to those of the buoys.

• Journal of the Korean Vacuum Society
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• 제5권4호
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• pp.371-376
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• 1996

Au films with a thickness around 1600 $\AA$ were deposited onto glass at room temperature by ion beam sputtering with a 5 cm cold-hollow ion gun at pressure $1\times 10^{-6}-1\times 10^{-5}$ Torr. Irradiation of the Au deposited samples was carried out at pressure of $7\times 10^{-6}$ Torr. For the sputter depositions, $Ar^+$ ion energy was 1 keV, and the current density at the substrate surface was 15 $\mu$A/$\textrm{cm}^2$. Effects of 1 keV $Ar^+$ ion dose($I_d$) between $1\times 10^{16}\; and\;2\times 10^{17}\;Ar^+\textrm{cm}^{-2}$on properties such as crystallinity, surface roughness and adhesion, etc. of the films have been investigated. The Au films sputtered by $Ar^+$ ion beam had only (111) plane and the X-ray intensity of the films decreased with increase of $I_d$. The thickness of Au films reduced with Id. $R_{ms}$ surface roughness of the films increased from 16 $\AA$ at as-deposited to 1118 $\AA$ at ion dose= $2\times 10^{17}\;Ar^+\textrm{cm}^{-2}$. Adhesion of Au film on sputtered at $I_d$= $2\times 10^{17}\;Ar^+\textrm{cm}^{-2}$ was 9 times greater than that of Au film with untreated, as determined by a scratch test.

• Tuberculosis and Respiratory Diseases
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• 제45권1호
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• pp.45-56
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• 1998

Background: Lung cancer continues to increase worldwide. Also, the proportion of female patients incease and adenocarcinoma is the predominant histological type among lung cancer in many western countries. So, we studied these current trends of lung cancer by clinical approach of recent patients from our department Method: We conducted a retrospective analysis on 212 subjects who were diagnosed with lung cancer at the department of chest medicine in National Medical Center between January 1990 and July 1996. The contents of analysis were patient's profile, clinical manifestation, smoking habits, accuracy of diagnostic methods, histological cell type, staging and treatment, etc. Results: The results were as follows. 1) The ratio of male to female was 5.2 : 1. The peak incidence of age was 7th decade(35.4%). 2) Chief complaints were cough, dyspnea and chest pain, etc. The most common duration of symptoms before the first admission was less than 3 months(57.7%). On the other side, duration more than 1 year represented 6.5%. The early diagnosed patients has been increased from the 1980s. 3) Smokers among the total patients were 77.2%. The proportion of smokers in sqamous cell carcinoma, small cell carcinoma and adenocarcinoma were 88.4%, 85.7% and 55.7%, respectively. Smoking history and histological cell type were correlated in squamous and small cell carcinoma. 4) Squamous cell carcinoma is still the predominant histological type (44.8%), but, adenocarcinoma increased more than the previous study(30.7%). The other histological types were small cell carcinoma(17.0%) and large cell carcinoma(3.8%) in order of their proportions. 5) The accuracy of diagnostic methods were as follows: sputum cytology 75.3%, bronchoscopic biopsy 65.7%, lymph node aspiration cytology 95.8%, percutaneous lung aspiration cytology 94.6% and open lung biopsy 100%. The general accuracies of diagnostic methods were improved than previous studies. 6) Performance status scales on admission were relatively good. After diagnosis, chemotherapy and/or radiotherapy were undertaken in 69.3% of the patients, and only 7.5% of the patients were operated. Conclusion: In our study, squamous cell carcinoma is still the predominant histological cell type, but, adenocarcinoma continues to increase. Because adenocarcinoma is less correlated with smoking habits, further evaluation of other carcinogens than smoking is requested. Screening and early diagnosis of lung cancer is important for good performance status scales in spite of advanced stages. But, we think that the prevention, for example, stop smokings is more important as because of no perfect treatment for lung cancer.

• Journal of Energy Engineering
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• 제28권3호
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• pp.65-79
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• 2019

The study attempted to estimate the optimal facility capacity by combining renewable energy sources that can be connected with gas CHP in industrial complexes. In particular, we reviewed industrial complexes subject to energy use plan from 2013 to 2016. Although the regional designation was excluded, Sejong industrial complex, which has a fuel usage of 38 thousand TOE annually and a high heat density of $92.6Gcal/km^2{\cdot}h$, was selected for research. And we analyzed the optimal operation model of CHP Hybrid System linking fuel cell and photovoltaic power generation using HOMER Pro, a renewable energy hybrid system economic analysis program. In addition, in order to improve the reliability of the research by analyzing not only the heat demand but also the heat demand patterns for the dominant sectors in the thermal energy, the main supply energy source of CHP, the economic benefits were added to compare the relative benefits. As a result, the total indirect heat demand of Sejong industrial complex under construction was 378,282 Gcal per year, of which paper industry accounted for 77.7%, which is 293,754 Gcal per year. For the entire industrial complex indirect heat demand, a single CHP has an optimal capacity of 30,000 kW. In this case, CHP shares 275,707 Gcal and 72.8% of heat production, while peak load boiler PLB shares 103,240 Gcal and 27.2%. In the CHP, fuel cell, and photovoltaic combinations, the optimum capacity is 30,000 kW, 5,000 kW, and 1,980 kW, respectively. At this time, CHP shared 275,940 Gcal, 72.8%, fuel cell 12,390 Gcal, 3.3%, and PLB 90,620 Gcal, 23.9%. The CHP capacity was not reduced because an uneconomical alternative was found that required excessive operation of the PLB for insufficient heat production resulting from the CHP capacity reduction. On the other hand, in terms of indirect heat demand for the paper industry, which is the dominant industry, the optimal capacity of CHP, fuel cell, and photovoltaic combination is 25,000 kW, 5,000 kW, and 2,000 kW. The heat production was analyzed to be CHP 225,053 Gcal, 76.5%, fuel cell 11,215 Gcal, 3.8%, PLB 58,012 Gcal, 19.7%. However, the economic analysis results of the current electricity market and gas market confirm that the return on investment is impossible. However, we confirmed that the CHP Hybrid System, which combines CHP, fuel cell, and solar power, can improve management conditions of about KRW 9.3 billion annually for a single CHP system.

• Korean Journal of Heritage: History & Science
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• 제47권2호
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• pp.86-113
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• 2014

This study has researched the characteristics and elements of Chwibyeong (翠屛), a sort of trellis in the Joseon Dynasty through the old documents, and the original form of Chwibyeong at Juhapru (宙合樓) in Changdeuk Palace. The results were as follow. First, as the result of literatures analysis for Imwon-gyeongje-ji (林園經濟志) and Jeungbo-sallim-gyeongje (增補山林經濟), the plant screen was classified as kinds of support[frame] material, plants and methods of planting. It was found that the supports of Chwibyeong were made of bamboo or the material such as the Jinjangmok (眞長木: a stick of oak) and Giryu (杞柳: Salix purpurea var. japonica). The evergreen coniferous trees including Pinus densiflora, Taxus cuspidata and Thuja orientalis were mainly used for the plant material of Chwibyeong. The general planting method of Chwibyeong was to plant on the ground, but sometimes the container planting was also found on the artificial ground. Second, the term of 'Chwibyeong' in the literatures was used in only the screen made by evergreen trees, and the superordinate category term of it was indicated by 'byeong (屛)'. Therefore Chwibyeong was a compound word formed from 'chwi (翠)' which means the characteristics of evergreen and 'byeong' as tree screen which the support was made by bamboo. And Chwibyeong had semantic context which was combined with the literary symbolization to describe a landscape of green peak and Taoist ideology be inherent from 'twelve peaks of Musan[巫山十二峰]' in Sichuan sheng (四川省). Thirdly, the photograph of Chwibyeong at Juhapru taken by the 1880s, showed that Chwibyeong was made with coniferous trees and was almost 2 meters high. The Chwibyeong at Juhapru was removed during the Japanese colonial era, but a few yew trees(Taxus cuspidata) used for Chwibyeong are still remaining. And some Juniperus chinensis which the composition time is unclear, were cultivated while hung loose its branchs at the sides of Eosumun (魚水門). This Junipers were presumed to be planted by Japanese after Japanese annexation of Korea(1910), and it was judged that both of the roofs of Eosumun's side gates might have been transformed into Japanese style at the same time. Lastly, Chwibyeong at Juhapru was restored in 2008 but it was restored in wrong way from original form without precise research. Especially Chwibyeong was restored with Sasa boreralis which is damaged by frost, so it requires exertion that should revive the originals to plant original material as much as possible. And it needs the development of fabrication technique for Chwibyeong and the application to current landscape architecture.

• Journal of the Mineralogical Society of Korea
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• 제32권1호
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• pp.41-49
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• 2019

Probing the Na environments in Na silicate and aluminosilicate glasses is essential to the macroscopic properties of melts in the Earth. In particular, exploring the atomic structure of Na silicate and aluminosilicate glasses reveals Na-O distance, which plays an important role in transport properties of melts. Here we report the local environment around Na using $^{23}Na$ magic angle spinning (MAS) NMR. We also obtain $^{23}Na$ isotropic chemical shift (${\delta}_{iso}$) of Na silicate and aluminosilicate glasses with varying composition using Dmfit program. The Q mas 1/2 model simulates the experimental results with three simulated peaks while the CzSimple model simulates with one peak. The ${\delta}_{iso}$ decreases with increasing $SiO_2$ content in Na silicate and aluminosilicate glasses. The ${\delta}_{iso}$ increases with increasing $Na_2O$ content in Na-Ca silicate and Na aluminosilicate glasses when the $SiO_2$ content is fixed. Considering the ${\delta}_{iso}$ of Na aluminosilicate glasses available in the previous studies, together with the current simulation results, we confirm that the ${\delta}_{iso}$ has positive correlation with Al / (Al + Si). Those experimental results were reproduced better using Q mas 1/2 model. The disorder of Na in Na silicate and aluminosilicate glasses can be revealed through the simulation of 1D $^{23}Na$ MAS NMR spectra using Dmfit program in a short time.

• Applied Chemistry for Engineering
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• 제34권3호
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• pp.258-263
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• 2023

In this study, conductive polymers and the enzyme tyrosinase (Tyr) were deposited on the surface of a screen printed carbon electrode (SPCE), which can be fabricated as a disposable sensor chip, and applied to the detection of bisphenol F (BPF), an endocrine disruptor with proven links to male diseases and thyroid disorders, using electrochemical methods. On the surface of the SPCE working electrode, which was negatively charged by oxygen plasma treatment, a positively charged conductive polymer, poly(diallyldimethyl ammonium chloride) (PDDA), a negatively charged polymer compound, poly(sodium 4-styrenesulfonate) (PSS), and another layer of PDDA were layered by electrostatic attraction in the order of PDDA, PSS, and finally PDDA. Then, a layer of Tyr, which was negatively charged due to pH adjustment to 7.0, was added to create a PDDA-PSS-PDDA-Tyr sensor for BPF. When the electrode sensor is exposed to a BPF solution, which is the substrate and target analyte, 4,4'-methylenebis(cyclohexa-3,5-diene-1,2-dione) is generated by an oxidation reaction with the Tyr enzyme on the electrode surface. The reduction process of the product at 0.1 V (vs. Ag/AgCl) generating 4,4'-methylenebis(benzene-1,2-diol) was measured using cyclic and differential pulse voltammetries, resulting in a change in the peak current with respect to the concentration of BPF. In addition, we compared the detection performance of BPF using an ionic liquid electrolyte as an alternative to phosphate-buffered saline, which has been used in many previous sensing studies. Furthermore, the selectivity of bisphenol S, which acts as an interfering substance with a similar structure to BPF, was investigated. Finally, we demonstrated the practical applicability of the sensor by applying it to analyze the concentration of BPF in real samples prepared in the laboratory.

• The Journal of the Society of Stroke on Korean Medicine
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• 제11권1호
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• pp.9-17
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• 2010

Objectives : This study was aimed to evaluate the current status of East-West integrated treatment in stroke and brain disease and to discuss further plans. Methods : The medical records of patients who visited the stroke and brain disease center at Kyung Hee University, East-West Neo Medical Center from May 2006 to August 2010 were evaluated. The general characteristics of patients who underwent integrated treatment, trend in the number of cross referrals were initially evaluated. Later major disorders, the reasons of referrals and the number of visits in outpatients were analyzed. Results : 1. 3496 patients were referred from the eastern medical hospital to the western medical hospital and 2440 patients from the western medical hospital to the eastern medical hospital. The number of patients reached a peak alter the opening of the hospital and has decreased from then on. Referrals of female patients were more than those of male patients and patients over 50 years old were the most. 2. Admitted patients with stroke of chronic stage were most commonly referred from the eastern medical hospital to the western medical hospital and cerebral infarction was most common from the western medical hospital to the eastern medical hospital. Among the outpatients cerebral infarction topped from east to west, and stroke of chronic stage from west to east. 3. 36.6% of the patients from east to west received integrated treatment more than 3 times and 28.6% from west to east. Headache was the second most common reason to be referred from west to east and 36.7% of patients didn't continue to have either of the treatment and 30.3% received eastern treatment only, Conclusions: According to this study, chronic stroke management was successfully performed in the outpatient clinic in the form of East-West integration treatment. Further research on other diseases such as headache is recommended.

• Analytical Science and Technology
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• 제20권4호
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• pp.308-314
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• 2007

The analytical method of HPLC with the radial-flow electrochemical cell (RFEC) has been developed to determine doxorubicin, epirubicin, nogalamycin, daunorubicin and idarubicin simultaneously by employing a reversed-phase chromatography. Anthracyclines were detected at -0.74 V vs. a Ag/AgCl (0.01 M NaCl) reference electrode, a potential of diffusion current plateau in the mobile phase. At a $V_f$ of 1.0 mL/min doxorubicin, epirubicin, daunorubicin and idarubicin appeared at a retention time ($t_r$) of 6.4 min, 7.4 min, 12.7 min and 18.4 min, respectively, while at a $V_f$ of 0.6 mL/min, doxorubicin, epirubicin, nogalamycin, daunorubicin and idarubicin appeared at a $t_r$ of 9.9 min, 11.5 min, 13.5 min, 19.6 min and 28.7 min, respectively. The linearity between each anthracycline injected ($2.40{\times}10^{-7}M{\sim}1.42{\times}10^{-5}M$) and peak area (charge) was excellent with the square of the correlation coefficient ($R^2$) higher than 0.999. The detection limits were $1.0{\times}10^{-8}M{\sim}1.5{\times}10^{-7}M$ for the five anthracyclines. Within-day precision for the five anthracyclines were in reasonable relative standard deviations less than 3 % ($1.00{\times}10^{-6}M{\sim}1.42{\times}10^{-5}M$) except the lower concentrations less than $0.7{\mu}M$. Solid phase extractions of $1.00{\times}10^{-5}M$ epirubicin, $0.48{\times}10^{-5}M$ nogalamycin and $1.52{\times}10^{-5}M$ daunorubicin from human serum with a $C_{18}$ cartridge resulted in 97 %, 100 % and 90 % of recoveries, respectively.

• Journal of Internet Computing and Services
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• 제14권5호
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• pp.69-76
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• 2013

The incidence of globally infectious and pathogenic diseases such as H1N1 (swine flu) and Avian Influenza (AI) has recently increased. An infectious disease is a pathogen-caused disease, which can be passed from the infected person to the susceptible host. Pathogens of infectious diseases, which are bacillus, spirochaeta, rickettsia, virus, fungus, and parasite, etc., cause various symptoms such as respiratory disease, gastrointestinal disease, liver disease, and acute febrile illness. They can be spread through various means such as food, water, insect, breathing and contact with other persons. Recently, most countries around the world use a mathematical model to predict and prepare for the spread of infectious diseases. In a modern society, however, infectious diseases are spread in a fast and complicated manner because of rapid development of transportation (both ground and underground). Therefore, we do not have enough time to predict the fast spreading and complicated infectious diseases. Therefore, new system, which can prevent the spread of infectious diseases by predicting its pathway, needs to be developed. In this study, to solve this kind of problem, an integrated monitoring system, which can track and predict the pathway of infectious diseases for its realtime monitoring and control, is developed. This system is implemented based on the conventional mathematical model called by 'Susceptible-Infectious-Recovered (SIR) Model.' The proposed model has characteristics that both inter- and intra-city modes of transportation to express interpersonal contact (i.e., migration flow) are considered. They include the means of transportation such as bus, train, car and airplane. Also, modified real data according to the geographical characteristics of Korea are employed to reflect realistic circumstances of possible disease spreading in Korea. We can predict where and when vaccination needs to be performed by parameters control in this model. The simulation includes several assumptions and scenarios. Using the data of Statistics Korea, five major cities, which are assumed to have the most population migration have been chosen; Seoul, Incheon (Incheon International Airport), Gangneung, Pyeongchang and Wonju. It was assumed that the cities were connected in one network, and infectious disease was spread through denoted transportation methods only. In terms of traffic volume, daily traffic volume was obtained from Korean Statistical Information Service (KOSIS). In addition, the population of each city was acquired from Statistics Korea. Moreover, data on H1N1 (swine flu) were provided by Korea Centers for Disease Control and Prevention, and air transport statistics were obtained from Aeronautical Information Portal System. As mentioned above, daily traffic volume, population statistics, H1N1 (swine flu) and air transport statistics data have been adjusted in consideration of the current conditions in Korea and several realistic assumptions and scenarios. Three scenarios (occurrence of H1N1 in Incheon International Airport, not-vaccinated in all cities and vaccinated in Seoul and Pyeongchang respectively) were simulated, and the number of days taken for the number of the infected to reach its peak and proportion of Infectious (I) were compared. According to the simulation, the number of days was the fastest in Seoul with 37 days and the slowest in Pyeongchang with 43 days when vaccination was not considered. In terms of the proportion of I, Seoul was the highest while Pyeongchang was the lowest. When they were vaccinated in Seoul, the number of days taken for the number of the infected to reach at its peak was the fastest in Seoul with 37 days and the slowest in Pyeongchang with 43 days. In terms of the proportion of I, Gangneung was the highest while Pyeongchang was the lowest. When they were vaccinated in Pyeongchang, the number of days was the fastest in Seoul with 37 days and the slowest in Pyeongchang with 43 days. In terms of the proportion of I, Gangneung was the highest while Pyeongchang was the lowest. Based on the results above, it has been confirmed that H1N1, upon the first occurrence, is proportionally spread by the traffic volume in each city. Because the infection pathway is different by the traffic volume in each city, therefore, it is possible to come up with a preventive measurement against infectious disease by tracking and predicting its pathway through the analysis of traffic volume.