• Journal of the Korean Ceramic Society
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• v.42 no.4
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• pp.245-250
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• 2005

ZnO was deposited on sapphire single crystal substrate by an ultrasonic pyrolysis of Zinc Acetate Dehydrate (ZAH) with carrying Ar gas. Through Thermogravimetry-Differential Scanning Calorimetry(TG-DSC), zinc acetate dihydrate was identified to be dissolved into ZnO above $380^{\circ}C$. ZnO deposited at $380-700^{\circ}C$ showed polycrystalline structures with ZnO (101) and ZnO (002) diffraction peaks like bulk ZnO in XRD, and from which c-axis strain ${\Sigma}Z=0.2\%$ and compressive biaxial stress$\sigma=-0.907\;GPa$ was obtained for the ZnO deposited $400^{\circ}C$. Scanning electron microscope revealed that microstructures of the ZnO were dependent on the deposition temperature. ZnO grown below temperature $600^{\circ}C$ were aggregate consisting of zinc acetate and ZnO particles shaped with nanoblades. On the other hand the grain of the ZnO deposited at $700^{\circ}C$ showed a distorted hexagonal shape and was composed of many ultrafine ZnO powers of 10-25 nm in size. The formation of these ulrafine nm scale ZnO powers was explained by the model of random nucleation mechanism. The optical property of the ZnO was analyzed by the photoluminescence (PL) measurement.

• The Journal of Korean Medicine
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• v.31 no.4
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• pp.151-163
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• 2010

Objective: We investigated the oral malodor inhibitory effect of Scutellariae Radix (SR), Phellodendri Cortex (PC), Moutan Cortex (MTC) and Magnoliae Cortex (MGC) for the development of a gargle solution. Methods: 1. Against P. gingivalis and Pr. intermedia, the minimal bactericidal concentration (MBC) and the change of viable cells that were exposed to 1% each herbal extract were observed. 2. Deodorizing activity of 2% herbal extract and Garglin $Mint^{(R)}$ against methyl mercaptan were evaluated by gas chromatography (GC). 3. We used the salivary sediment system (SSS) as the malodor model. 4. The clinical examination was repeated 3 times by 2 subjects by $Halimeter^{(R)}$. Baseline VSC of each subject was measured. Then, the control subject gargled with cysteine for 30 sec. After 4 min, subjects would gargle for 30 seconds with herbal extracts (2%) and Garglin $Mint^{(R)}$. Subsequently, the concentration of VSC was measured at 0, 4, 8, 12, 16, 20, 40 and 60 minutes. Results: 1. Against P. gingivalis, MBC of SR, PC and MTC was 0.1%, and MBC of MGC was 1%. Removal time of P. gingivalis was as follows; 5 hr in MGC, 24 hr in SR and PC, and 48 hr in MTC. Against Pr. intermedia, MBC of SR and PC was 0.5%, and MBC of MTC, MGC was 1%. Removal time of Pr. intermedia was as follows; 5 hr in MTC and 24 hr in SR, PC and MGC. 2. Deodorizing effect of herbal extracts against methyl mercaptan was as follows; MGC and MTC had 100%, SR had 82.22%, PC had 66.60%, Garglin $Mint^{(R)}$ had 40.54%. 3. In the experiment using SSS, PC and MTC had statistically significant malodor-inhibitory effects (p<.05). 4. In the clinical examination, PC and MGC had statistically significant inhibitory effects at every elapsed time compared to the control subject. MTC had that until 40 min. SR had that at 0, 4, 8, 20, and 60 min. Conclusions: SR, PC, MTC and MGC have an antibacterial effect and the chemical removable activity of the oral malodor caused by VSC. These four herbs could have potential as effective anti-malodor agents.

• Environmental and Resource Economics Review
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• v.18 no.1
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• pp.53-73
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• 2009

This study examines the existence of ${\beta}$-convergence of carbon dioxide emissions in 24 countries over the period 1971~2002. For that purpose, The model of economic growth developed by Barro and Sala-i-Martin (1995) is extended and conducted Dynamic panel analysis and unit root testing by employing the panel stationarity test of Levin et al. (2002) and 1m et al. (2003). A dynamic panel estimation is well known method including capacity to control for both the endogeneity problem and the unobserved country-specific effects problem. Dynamic panel estimation method has been widely used in similar empirical studies. therefore, we also used the dynamic panel estimation method in our estimation. The result show that evidence of ${\beta}$-convergence exists among both the Obligatory GHG reduction countries (Annex) and the Non-obligatory GHG reduction countries (Non-Annex). but China discharge amount of $CO_2$ gas more than any other country. This fact can cause some bias in overall test. and so we reexamined test of convergence for Non-annex countries excluding china. As expected, in the Non-annex countries excluding china, I couldn't find any evidence of convergence.

• Journal of Astronomy and Space Sciences
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• v.21 no.4
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• pp.391-398
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• 2004

Far-ultraviolet Imaging Spectrograph (FIMS) is the main payload of the Korea's first scientific micro satellite STSAT-1, which was launched at Sep. 27 2003 successfully. Major objective of FIMS is observing hot gas in the Galaxy in FUV bands to diagnose the energy flow models of the interstellar medium. Supernova remnants, molecular clouds, and Aurora emission in the geomagnetic pole regions are specific targets for pointing observation. Although the whole system was calibrated before launch, it is essential to perform on-orbit calibration for data analysis. For spectral calibration, we observed airglow lines in the atmosphere since they provide good spectral references. We identify and compare the observed airglow lines with model calculations, and correct the spectral distortion appeared in the detector system to improve the spectral resolution of the system.

• Journal of Microbiology and Biotechnology
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• v.28 no.2
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• pp.199-209
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• 2018

Volatile organic compounds (VOCs) are increasingly been recognized as the chemical mediators of mold interactions, shaping their community dynamics, growth, and metabolism. Herein, we selectively examined the time-correlated (0 D-11 D, where D = incubation days) effects of intraspecies VOC-mediated interactions (VMI) on Aspergillus oryzae KCCM 60345 (S1), following co-cultivation with partner strain A. oryzae KACC 44967 (S2), in a specially designed twin plate assembly. The comparative evaluation of $S1_{VMI}$ (S1 subjected to VMI with S2) and its control ($S1_{Con}$) showed a notable disparity in their radial growth ($S1_{VMI}$ < $S1_{Con}$) at 5 D, protease activity ($S1_{VMI}$ > $S1_{Con}$) at 3-5 D, amylase activity ($S1_{VMI}$ < $S1_{Con}$) at 3-5 D, and antioxidant levels ($S1_{VMI}$ > $S1_{Con}$) at 3 D. Furthermore, we observed a distinct clustering pattern for gas chromatography-time of flight-mass spectrometry datasets from 5 D extracts of $S1_{VMI}$ and $S1_{Con}$ in principle component analysis (PC1: 30.85%; PC2: 10.31%) and partial least squares discriminant analysis (PLS-DA) (PLS1: 30.77; PLS2: 10.15%). Overall, 43 significantly discriminant metabolites were determined for engendering the metabolic variance based on the PLS-DA model (VIP > 0.7, p < 0.05). In general, a marked disparity in the relative abundance of amino acids ($S1_{VMI}$ > $S1_{Con}$) at 5 D, organic acids ($S1_{VMI}$ > $S1_{Con}$) at 5 D, and kojic acid ($S1_{VMI}$ < $S1_{Con}$) at 5-7 D were observed. Examining the headspace VOCs shared between S1 and S2 in the twin plate for 5 D incubated samples, we observed the relatively higher abundance of C-8 VOCs (1-octen-3-ol, (5Z)-octa-1,5-dien-3-ol, 3-octanone, 1-octen-3-ol acetate) having known semiochemical functions. The present study potentially illuminates the effects of VMI on commercially important A. oryzae's growth and biochemical phenotypes with subtle details of altered metabolomes.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.7
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• pp.353-363
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• 2016

In this study, traditional treatment scenario of food wastes that collected and transported food waste is recycled in large treatment facilities and suggested treatment scenario of onsite zero discharge system that food waste is treated in housing complex were supposed. The scenarios were compared and analyzed by capital expenditure, oil consumption, $CO_2$ emission quantity, operating expenditure and management expenses. The capital expenditure, oil consumption and $CO_2$ emission quantity of small scale dispersion dealing method is the lowest compared to traditional treatment method. As a results, it is possible to obtain the effect that operating expenditure was reduced by 91% and management expenses was reduced by 40% with suggested treatment method. The treatment method that have low capital expenditure is tend to lower oil consumption and $CO_2$ emission quantity. The small scale dispersion dealing method have the lowest capital expenditure, oil consumption and $CO_2$ emission quantity and the linked method with sewage treatment have the highest expenditure and $CO_2$ emission quantity. Eventually, the optimal model of onsite zero discharge system in housing complex is small scale dispersion dealing method.

• Environmental and Resource Economics Review
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• v.20 no.3
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• pp.531-565
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• 2011

All previous studies analyzing multivariate time series data of EUA (European Union Allowance) price commonly used endogenous variables within the four variables and included the period from April to June of 2006 in the analysis, when the price distortion occurred. This study uses graph theory and structural vector error correction model (SVECM) to analyze the daily time series data of the EUA (European Union Allowance) price. As endogenous variables, five variables are considered for the analysis, including prices of crude oil, natural gas, electricity and coal in addition to carbon price. Data period is Phase 2 period (April 21, 2008 to March 31, 2010) to avoid the EUA price distortion of Phase 1 period (2005~2007). Further, the monthly data including the economic variables as endogenous variables are analyzed.

• Journal of Chest Surgery
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• v.49 no.3
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• pp.145-150
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• 2016

Background: Extracorporeal circulation (ECC) can induce alterations in blood viscoelasticity and cause red blood cell (RBC) aggregation. In this study, the authors evaluated the effects of pump flow pulsatility on blood viscoelasticity and RBC aggregation. Methods: Mongrel dogs were randomly assigned to two groups: a nonpulsatile pump group (n=6) or a pulsatile pump group (n=6). After ECC was started at a pump flow rate of 80 mL/kg/min, cardiac fibrillation was induced. Blood sampling was performed before and at 1, 2, and 3 hours after ECC commencement. To eliminate bias induced by hematocrit and plasma, all blood samples were adjusted to a hematocrit of 45% using baseline plasma. Blood viscoelasticity, plasma viscosity, hematocrit, arterial blood gas analysis, central venous $O_2$ saturation, and lactate were measured. Results: The blood viscosity and aggregation index decreased abruptly 1 hour after ECC and then remained low during ECC in both groups, but blood elasticity did not change during ECC. Blood viscosity, blood elasticity, plasma viscosity, and the aggregation index were not significantly different in the groups at any time. Hematocrit decreased abruptly 1 hour after ECC in both groups due to dilution by the priming solution used. Conclusion: After ECC, blood viscoelasticity and RBC aggregation were not different in the pulsatile and nonpulsatile groups in the adult dog model. Furthermore, pulsatile flow did not have a more harmful effect on blood viscoelasticity or RBC aggregation than nonpulsatile flow.

• Journal of Korea Water Resources Association
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• v.41 no.4
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• pp.379-394
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• 2008

Recently, extreme precipitation events beyond design capacity of hydraulic system have been occurred and this is the causes of failure of hydraulic structure for flood prevention and of severe flood damage. Therefore it is very important to understand temporal and spatial characteristics of extreme precipitation events as well as expected changes in extreme precipitation events and distributional characteristics during design period under future climate change. In this paper, climate change scenarios were used to assess the impacts of future climate change on extreme precipitation. Furthermore, analysis of future extreme precipitation characteristics and I-D-F analysis were carried out. This study used SRES B2 greenhouse gas scenario and YONU CGCM to simulate climatic conditions from 2031 to 2050 and statistical downscaling method was applied to establish weather data from each of observation sites operated by the Korean Meteorological Administration. Then quantile mapping of bias correction methods was carried out by comparing the simulated data with observations for bias correction. In addition Modified Bartlett Lewis Rectangular Pulse(MBLRP) model (Onof and Wheater, 1993; Onof 2000) and adjust method were applied to transform daily precipitation time series data into hourly time series data. Finally, rainfall intensity, duration, and frequency were calculated to draw I-D-F curve. Although there are 66 observation sites in Korea, we consider here the results from only Seoul, Daegu, Jeonju, and Gwangju sites in this paper. From the results we found that the rainfall intensity will be increased and the bigger intensity will be occurred for longer rainfall duration when we compare the climate conditions of 2030s with present conditions.

• Tribology and Lubricants
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• v.36 no.2
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• pp.105-115
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• 2020

This paper presents a numerical study on the rotordynamic analysis of a dual-spool turbofan engine in the context of blade defect events. The blades of an axial-type aeroengine are typically well aligned during the compressor and turbine stages. However, they are sometimes exposed to damage, partially or entirely, for several operational reasons, such as cracks due to foreign objects, burns from the combustion gas, and corrosion due to oxygen in the air. Herein, we designed a dual-spool rotor using the commercial 3D modeling software CATIA to simulate blade defects in the turbofan engine. We utilized the rotordynamic parameters to create two finite element Euler-Bernoulli beam models connected by means of an inter-rotor bearing. We then applied the unbalanced forces induced by the mass eccentricities of the blades to the following selected scenarios: 1) fully balanced, 2) crack in the low-pressure compressor (LPC) and high pressure compressor (HPC), 3) burn on the high-pressure turbine (HPT) and low pressure compressor, 4) corrosion of the LPC, and 5) corrosion of the HPC. Additionally, we obtained the transient and steady-state responses of the overall rotor nodes using the Runge-Kutta numerical integration method, and employed model reduction techniques such as component mode synthesis to enhance the computational efficiency of the process. The simulation results indicate that the high-vibration status of the rotor commences beyond 10,000 rpm, which is identified as the first critical speed of the lower speed rotor. Moreover, we monitored the unbalanced stages near the inter-rotor bearing, which prominently influences the overall rotordynamic status, and the corrosion of the HPC to prevent further instability. The high-speed range operation (>13,000 rpm) coupled with HPC/HPT blade defects possibly presents a rotor-case contact problem that can lead to catastrophic failure.