• Korean Chemical Engineering Research
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• v.49 no.2
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• pp.238-243
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• 2011

In this study, we attempted a structural analysis in order to design a balloon type extracorporeal membrane oxygenator that can induce blood flow without using blood pumps for the purpose of complementing the weakness in the existing extracorporeal membrane oxygenator. To analyze the flow characteristic of the blood flow within the virtual model of extracorporeal membrane oxygenator, computational fluid dynamics(CFD) modeling method was used. The operating principle of this system is to make the surface of the extracorporeal membrane oxygenator keep contracting and dilating regularly by applying pressure load using a balloon, and the 'ime Function Value'that changes according to the time was applied by calculating a half cycle of sine waveform and a cycle of sine.waveform Under the assumption that the uni-directional blood flow could be induced if the balloon type extracorporeal membrane oxygenator was designed as per the method described above, we conducted a structural analysis accordingly. We measured and analyzed the velocity and pressure of blood flow at both inlet and outlet of the extracorporeal membrane oxygenator through CFD simulation. As a result of the modeling, it was confirmed that there was a flow in accord with the direction of the blood by the contraction/dilation. With CFD simulation, the characteristics of blood flow can be predicted in advance, so it is judged that this will be able to provide the most optimized design in producing an extracorporeal membrane oxygenator.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.11
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• pp.1415-1422
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• 2011

Sheet aluminum alloys used in manufacturing of machine structures for transportation show the difference of crack growth speed depending on thickness under the constant fatigue stress condition. The referred thickness effect is a major fatigue failure property of sheet aluminum alloys. In this work, we identified the thickness effect in fatigue test of thick plate and thin plate of Al 2024-T3 alloy under the constant fatigue stress condition, and presented the thickness effect to a correlative equation, $U_{i}^{equ}=f(R_t)$ which is determined by the shape factor, thickness ratio, $R_t$ and the loading factor, equivalent effective stress intensity ratio depending on thickness, $U_{i}^{equ}$. And we analyzed quantitatively the crack growth retardation behavior in thin plate compared to thick plate by the thickness effect using ${\Delta}K$ conversion method. We obtained such values as decrement of thickness(DoT), decrement of stress intensity factor range, ${\Delta}K$ (DoS) and identified the relation between them to present the nature of thickness effect in this work.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.2
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• pp.163-173
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• 2007

Lipid peroxidation is one of the main manifestations of oxidative damage and has been found to play an important role in the toxicity and carcinogenesis of many carcinogens. This study was carried out to determine the effects of vitamin C on lipid contents and fatty acid compositions of serum and liver in male rats treated with radiation or aflatoxin $B_1\;(AFB_1)$. Six week-old male Sprague-Dawley rats were randomly divided into 7 groups; control group, radiation exposed group, $AFB_1$ treated group, X-ray and $AFB_1$ co-treated group. Three groups, except control group, were each further divided into vitamin C administered group and not administered groups. For this study, vitamin C was injected with 10 mg/kg of body weight by intraperitoneal injection and 1 hr later, 0.4 mg/kg of $AFB_1$ was injected by the same method. These administrations were repeated every 3 days over a period of 15 days. Only one time, X-ray was irradiated on whole liver with 1,500 cGy. Then vitamin C and AFB1 were administered by the same level and same method described above. On the 16th day of treatments, the animals were sacrificed. From the analysis of the serum lipid patterns, significant decrease (p<0.01) in triglyceride (TG) and total cholesterol levels were observed in X-ray and $AFB_1$ co treated group administered with vitamin C (group 7). In liver lipids, the levels of free cholesterol and total cholesterol were also decreased in X-ray and $AFB_1$ co treated group administered with vitamin C (group 7). The levels of serum free cholesterol and hepatic TG were not significantly different among all groups according to vitamin C administrations. The high density lipoprotein (HDL)-cholesterol level of serum was significantly (p<0.01) increased while the low density lipoprotein (LDL)-cholesterol level was decreased in X-ray and $AFB_1$ co treated group administered with vitamin C (group 7). In the phospholipid fatty-acid compositions of serum and liver tissue, group 3, 5 and 7 showed an increase in polyunsaturated fatty-acid (PUFA) but a decrease in saturated fatty acid (SFA) when compared to the control group. The composition ratio of fatty acid varied according to vitamin C administration. These results suggested that vitamin C has partly suppressive effects on lipid contents and fatty acid composition of serum and liver in rats treated by radiation and $AFB_1$.

• Korean Journal of Environmental Agriculture
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• v.26 no.4
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• pp.343-350
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• 2007

Three different experiments were carried out to investigate the runoff and erosion losses of endosulfan from sloped-field by rainfall. The mobility of endosulfan and which phase it was transported by were examined in adsorption study, the influence of rainfall pattern and slope degree on the pesticide loss were evaluated in simulated rainfall study, and the pesticide losses from soybean-grown field comparing with bare soil were measured in field lysimeter study. Adsorption parameter (K) of endosulfan ranged from 77 to 131 by adsorption method and K values by the desorption method were higher than those by the adsorption method. By the SSLRC's classification for pesticide mobility endosulfan was classified as non-mobile class ($K_{oc}>4,000$). Runoff and erosion loss of endosulfan by three rainfall scenarios ranged from 3.4 to 5.6%and from 4.4 to 15.6%of the amount treated. Endosulfan residues were mainly remained at the top 5 cm of soil depth after the simulated rainfall study. Pesticide loss in case of 30%-slope degree ranged from 0.6 to 0.9 times higher than those in case of 10%-slope degree. The difference of pesticide runoff loss was related with its concentration in runoff water and the difference of pesticide erosion loss would related closely with the quantity of soil eroded. Endosulfan losses from a series of lysimeter plots in sloped land by rainfall ranged from 5 to 35% of the amount treated. The erosion rate of endosulfan from soybean-plots was 66% of that from bare soil plots. The effect of slope conditions was not great for runoff loss, but was great for erosion loss as increasing to maximum $4{\sim}12$ times with slope degree and slope length. The peak runoff concentration of endosulfan in soybean-plots and bare soil plots ranged from 8 to 10 and from 7 to $9{\mu}gL^{-1}$ on nine plots with different slope degree and slope length. Therefore the difference of the peak runoff concentrations between bare soil plots and soybean-plots were not great.

• Economic and Environmental Geology
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• v.48 no.2
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• pp.147-160
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• 2015

In 2014, on 31 August and 1 September, the emissions of $CH_4$, $CO_2$, and $O_2$ gases were measured six times using the closed chamber method from exposed tidal flat sediments in the same position relative to the low point of the tidal cycle in the Eoeun-ri, Taean-gun, on the Mid-western Coast of Korea. The concentrations of $CH_4$ in the air sample collected in the chamber were measured using gas chromatography with an EG analyzer, model GS-23, within 6 hours of collection, and the other gases were measured in real time using a multi-gas monitor. The gas emission fluxes (source (+), and sink (-)) were calculated from a simple linear regression analysis of the changes in the concentrations over time. In order to see the surrounding parameters (water content, temperature, total organic carbon, average mean size of sediments, and the temperature of the inner chamber) were measured at the study site. On the first day, across three measurements during 5 hours 20 minutes, the observed $CO_2$ flux absorption was -137.00 to $-81.73mg/m^2/hr$, and the $O_2$ absorption, measured simultaneously, was -0.03 to $0.00mg/m^2/hr$. On the second day using an identical number of measurements, the $CO_2$ absorption was -20.43 to $-2.11mg/m^2/hr$, and the $O_2$ absorption -0.18 to $-0.14mg/m^2/hr$. The $CH_4$ absorption before low tide was $-0.02mg/m^2/hr$ (first day, Pearson correlation coefficient using the SPSS statistical analysis is -0.555(n=5, p=0.332, pronounced negative linear relationship)), and $-0.15mg/m^2/hr$ (second day, -0.915(n=5, p=0.030, strong negative linear relationship)) on both measurement days. The emitted flux after low tide on both measurement days reached a minimum of $+0.00mg/m^2/hr$ (+0.713(n=5, p=0.176, linear relationship which can be almost ignored)), and a maximum of $+0.03mg/m^2/hr$ (+0.194(n=5, p=0.754, weak positive linear relationship)) after low tide. However, the absolute values of the $CH_4$ fluxes were analyzed at different times. These results suggest that rate for $CH_4$ fluxes, even the same time and area, were influenced by changes in the tidal cycle characteristics of surface sediments for understanding their correlation with these gas emissions, and surrounding parameters such as physiochemical sediments conditions.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.7 s.110
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• pp.638-647
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• 2006

Recently, the DFT-Spread OFDM has been studied for the PAPR reduction. However, the DFT-Spread OFDM produces more ICI and SCI problems than OFDM because phase offset mismatch of the DFT spreading code results from the random phase noise in the oscillator. In this paper, at first, phase noise influence on the DFT-Spread OFDM system is theoretically analyzed in terms of the BER performance. Then, the conventional ICI self-cancellation methods are discussed and two kinds of ICI self-cancellation methods are newly proposed. Lastly, a new DFT-Spread OFDM system which selectively adopts the ICI self-cancellation technique is proposed to resolve the interference problem and PAPR reduction simultaneously. Proposednew DFT-Spread OFDM system can minimize performance degradation caused by phase noise, and still maintain the low PAPR property. Among the studied methods, DFT-Spread OFDM with data-conjugate method or newly proposed symmetric data-conjugate method show the significant performance improvements, compared with the DFT-Spread OFDM without ICI self-cancellation schemes. The data-conjugate method is slightly better than symmetric data-conjugate method.

• Journal of KIISE:Databases
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• v.34 no.5
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• pp.420-436
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• 2007

The choice of an effective indexing method is crucial to guarantee the performance of the spatial join operator which is heavily used in geographical information systems. The $R^*$-tree based method is renowned as one of the most representative indexing methods. In this paper, we propose an efficient spatial join technique based on the DOT(Double Transformation) index, and compare it with the spatial Join technique based on the $R^*$-tree index. The DOT index transforms the MBR of an spatial object into a single numeric value using a space filling curve, and builds the $B^+$-tree from a set of numeric values transformed as such. The DOT index is possible to be employed as a primary index for spatial objects. The proposed spatial join technique exploits the regularities in the moving patterns of space filling curves to divide a query region into a set of maximal sub-regions within which space filling curves traverse without interruption. Such division reduces the number of spatial transformations required to perform the spatial join and thus improves the performance of join processing. The experiments with the data sets of various distributions and sizes revealed that the proposed join technique is up to three times faster than the spatial join method based on the $R^*$-tree index.

• Journal of The Korean Society of Grassland and Forage Science
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• v.38 no.1
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• pp.44-52
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• 2018

This experiment was conducted at Suwon, Korea from 2013 to 2015. The objective of this study was to establish the optimum seeding rate, and to clarify the nitrogen fertilizer level for rye seed production in central and north area of Korea. We used Korean rye cultivar 'Gogu' for this test. We employed a split-plot design with three replications. The main plots were designed by three seeding levels (3, 5 and $7kg\;10a^{-1}$), but other sub-plots were randomly seeded. The plots were treated with three different nitrogen fertilizer levels (3, 6 and $9kg\;10a^{-1}$). The percentage of productive tiller, number of grain per spike, fertility rate, 1 liter weight, and 1000-grain weight decreased as seeding rate increased from $3kg\;10a^{-1}$ to $7kg\;10a^{-1}$, whereas the number of spike per $m^2$ increased. Therefore the grain yields of rye had less of an effect by increasing seeding rate. There was an increase in number of spike per $m^2$, number of grain per spike, and fertility rate as nitrogen fertilizer level increased from $3kg\;10a^{-1}$ to $9kg\;10a^{-1}$, but grain yields significantly not affected by the interaction of seeding rate ${\times}$ nitrogen fertilizer levels. However, the best seeding rate and nitrogen fertilizer level for rye seed production were 5 kg and $5{\sim}6kg\;10a^{-1}$, respectively, considering seed and fertilizer reduction and the prevention of pollution by excess fertilization.

• The Journal of the Korea Contents Association
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• v.13 no.4
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• pp.320-330
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• 2013

The purpose of this study is to increase efficiency of CPR through comparing the chest-compression quality between rescuer's simplified verbal order method and the continued verbal order method by utilizing voice meter during CPR. Subjects were 89 people(45 people for the experimental group, 44 people for the control group) who completed the 15-week CPR curriculum as undergraduates for the department of Emergency Medical Technology in C Province and were carried out by being randomly extracted. The group division was set for the experimental group as the group with the simplified verbal order and for the control group as the group with the continued verbal order. The period of measurement was progressed primarily(November 10, November 28, 2011) and secondarily(September 3-September 4, 2012). An analysis was used SPSS WIN 12.0 program. As a result of research, as for the implementation of appropriate chest compression(time, %), the quality was higher(p<.05) in the experimental group(102.86 times, 67.79%) than the control group(85.31 times, 55.84%). As a result of research, the chest compression(time, %) in the experimental group(102.86 times, 67.79%) had the higher effect of chest compression quality(p<.05) than the control group(85.31 times, 55.84%). On the other hand, the operation of weak chest compression(time) was higher in control group(61.13 times) than experimental group(35.54 times). The proper chest compression was shown(p<.05) in men of the experimental group as for gender and in over 60kg of the experimental group as for weight.

• Analytical Science and Technology
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• v.23 no.5
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• pp.485-491
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• 2010

A certified reference material (CRM) of KRISS 109-03-SSD was developed for the analysis of hazardous elements in soil. The target elements were As, Cd, Cr, Cu, Hg, Ni, Pb, Zn being regulated by the Soil Environment Conservation Act. Starting material was collected from tailing dump of an unworked tungsten mine at Sangdong (Gangwon-do, Korea). The starting material under-went through a series of fabricating process steps of screening, drying, grinding, sieving, blending, bottling, sterilization and was certified according to the ISO Guide 35. Isotope dilution-inductively coupled mass spectrometry (ID-ICP/MS) and instrumental neutron activation analysis (INAA) were used for the measurement. Homogeneity was tested according to ISO 13528 annex B. The certified values were determined using the results from two different methods or from two independent measurements using a method. Finally, certified values of seven elements of arsenic, cadmium, chromium, copper, lead, nickel and zinc were determined. Mercury did not satisfied the criteria of homogeneity and the result would be provided for information only, together with iron and tungsten. It was also studied, the extractable fraction of elements by aqua regia according to the ISO 11466 protocol being frequently studied for the purpose of environmental monitoring. It was performed as a inter-laboratory study by 6 laboratories of a public institute and universities. Standard deviation among the laboratories was much bigger than the uncertainty of the certified value. The result of inter-laboratory study on the extractable fraction will be provided for information, only.