• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.381-381
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• 2010

$(ZrO_2)_{0.66}(HfO_2)_{0.34}$ thin films as gate dielectrics have been proposed to overcome the problems of tunneling current and degradation mobility inachieving a thin equivalent oxide thickness. An extremely thin $SiO_2$ layer is used in order to separate the carrier in MOSFET channel from the dielectric field fluctuation caused by phonons in the dielectric which decreases the carrier mobility. The electronic and optical properties influenced the device performance to a great extent. $(ZrO_2)_{0.66}(HfO_2)_{0.34}$ dielectric films on p-Si (100) were grown by atomic layer deposition method, for which the conduction band offsets, valence band offsets and band gapswere obtained by using X-ray photoelectron spectroscopy and reflection electron energy loss spectroscopy. The band gap, valence and conduction band offset values for $(ZrO_2)_{0.66}(HfO_2)_{0.34}$ dielectric thin film, grown on Si substrate were about 5.34, 2.35 and 1.87 eV respectively. This band alignment was similar to that of $ZrO_2$. In addition, The dielectric function (k, $\omega$), index of refraction n and the extinction coefficient k for the $(ZrO_2)_{0.66}(HfO_2)_{0.34}$ thin films were obtained from a quantitative analysis of REELS data by comparison to detailed dielectric response model calculations using the QUEELS-$\varepsilon$(k, $\omega$)-REELS software package. These optical properties are similar with $ZrO_2$ dielectric thin films.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.6
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• pp.509-523
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• 2012

The sound quality based on design optimization, throughout the development process of various electronic office equipments, needs to be considered in order to respond the increased needs for the emotional satisfaction of customers in terms of psycho-acoustics. This paper focuses on how to describe the characteristics of operating sound radiated from laser printers by using various sound attributes, and to model the sound quality index that can properly evaluate the subjective preference on modification conditions in the improvement study quantitatively. Especially, the proposed verification process, in the form of combining the correlation based method and the decision error based method, was applied to improve the generality and reliability of a group of participants in the jury evaluation. The modified Aures tonality model was also proposed to improve the correlation coefficient with the mean response of participants by optimizing some parameters. As a result, the loudness, articulation index, roughness, tonality, fluctuation strength were used to model the sound quality index for laser printers by using the multiple-linear regression method. Through the improvement study, it was confirmed that replacing the absorbing materials is effective to reduce the tonalness radiated from the side of a reference printer model. Based on above results, it can be concluded that the proposed model has enough usefulness as quantitative evaluation index to evaluate the difference between modification conditions in the improvement study.

• Journal of Animal Science and Technology
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• v.49 no.1
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• pp.15-24
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• 2007

The purpose of this study was to evaluate the presence and differential expression of connexin isoforms in the efferent ductules (ED) of male rat reproductive tract during postnatal development. Total RNA was isolated from the ED collected from rats at 1 week, 2 weeks, 1 month, 3 months, and 6 months of ages. Expression of six connexin mRNAs of 14 isoforms tested was detected by semi-quantitative RT-PCR. Fluctuation of mRNA levels of connexins 26 and 30 was found according to ages. A significant decrease of connexin 31.1 mRNA level was observed in the ED at 1 month of age. The highest levels of connexin 37 and 45 mRNAs were detected in the ED of early developmental period, while the expression of connexin 43 was the lowest at 1 week of age. The present study demonstrates differential regulation on expression of connexin isoforms in the rat ED in age-dependent manner.

• Journal of Korea Port Economic Association
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• v.39 no.4
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• pp.295-308
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• 2023

Busan Port, as Korea's representative trading port, handles a variety of port cargo from bulk cargo to container cargo. Busan Port is currently functioning as a container specialized port for North Port and Busan New Port, and Gamcheon Port is also handling container cargo mainly in bulk cargo. This study intends to examine the overlapping cargoes and specialized cargoes between these ports and Busan Port as the amount of import and export cargoes in ports designated as trade ports in Korea is increasing. In order to understand the characteristics of the major cargoes handled in the port, the quantitative change is confirmed through the total cargo volume of major domestic ports and the trend of changes in import/export cargo between Busan Port and major ports is analyzed. There are many specialized investigation methods, but as the most basic method, we will examine quantitative changes and causes by simply examining the data for 10 years as the amount of change by cargo. In addition, the causes of these fluctuations should be reclassified into domestic and foreign causes by identifying changes in customers in different ports and shipping volumes, changes in consumption areas, and transshipment volumes. Through the analysis of the major cargo volume of each port, the characteristics and fluctuation trends of major cargo handled in Busan Port and other ports are identified, and the competitive cargoes of each port are verified. Through this, the characteristics and competitiveness of the port are inferred, and implications for the cargo volume of Busan Port and future countermeasures are suggested.

• Journal of Korea Water Resources Association
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• v.48 no.1
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• pp.57-67
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• 2015

One of main benefits of a dual polarization radar is improvement of quantitative rainfall estimation. In this paper, performance of two representative rainfall estimation methods for a dual polarization radar, JPOLE and CSU algorithms, have been compared by using data from a MOLIT S-band dual polarization radar. In addition, this paper presents evaluation of specific differential phase ($K_{dp}$) retrieval algorithm proposed by Lim et al. (2013). Current $K_{dp}$ retrieval methods are based on range filtering technique or regression analysis. However, these methods can result in underestimating peak $K_{dp}$ or negative values in convective regions, and fluctuated $K_{dp}$ in low rain rate regions. To resolve these problems, this study applied the $K_{dp}$ distribution method suggested by Lim et al. (2013) and evaluated by adopting new $K_{dp}$ to JPOLE and CSU algorithms. Data were obtained from the Mt. Biseul radar of MOLIT for two rainfall events in 2012. Results of evaluation showed improvement of the peak $K_{dp}$ and did not show fluctuation and negative $K_{dp}$ values. Also, in heavy rain (daily rainfall > 80 mm), accumulated daily rainfall using new $K_{dp}$ was closer to AWS observation data than that using legacy $K_{dp}$, but in light rain(daily rainfall < 80mm), improvement was insignificant, because $K_{dp}$ is used mostly in case of heavy rain rate of quantitative rainfall estimation algorithm.

• Korean Journal of Construction Engineering and Management
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• v.16 no.4
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• pp.70-79
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• 2015

With the rise of the interest in a renewable system, the importance of the Life Cycle Cost Analysis(LCCA), an economic evaluation tool, has been increasing. However, there is an inevitable gap between a real cost and an estimation from LCCA because of the uncertainty of the external environment in real world. As the input variables in an analysis, such as a real discount rate and an energy cost, ares subject to change as time goes by, strategic decision on the current operating system is made depending on the real cost. Current economic evaluation approaches have treated only the fluctuation of input variables without consideration of the flexibility in operation, which has consequently led to the impairment on the reliability of LCCA. Therefore, new approach needs to be proposed to consider both the uncertainty of input variables and operational flexibility. To address this issue, the application of the Real Option to LCCA is presented in this study. Through a case analysis of LCCA of a solar heating system, the limits and current status of LCCA are identified. As a result, quantitative presentation of strategic decisions has been added in the new approach to implement the traditional approach.

• Journal of Korean Society of Forest Science
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• v.105 no.3
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• pp.321-329
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• 2016

To estimate the sediment discharge controlled by sediment-filled check-dam and thereby enhancing factor for check-dam design and dredging criteria, we surveyed slope failures and stream-bed fluctuation caused by geomorphic disturbances (i.e., landslides and debris flows) in Inje, Gangwondo. In general, check-dams play roles for restraining and controlling sediment discharge within a section under the design equilibrium gradient and a section under the design flood gradient, respectively. The results in this study showed same pattern: that is, the closed type check-dam, which has a design restraint sediment discharge of $2,111m^3$, estimated to control a sediment discharge of $3,996m^3$ in the stream section within 250 m right upper area immediately after the disturbances occurred in 2006. As a result, a design control sediment discharge of the check-dam was larger than its design restraint sediment discharge. This represents that the check-dam is still having an own function for controlling sediment discharge although it exceeded the designed capacity by the sediment discharged from upstream during the disturbances. Our finding suggests that the sediment discharge controlling of check-dam may need to be evaluated separately from its sediment discharge restraint. Currently, the country, however, does not consider the design control (or restraint) sediment discharges, based on the actual field survey, as criteria for check-dam design and/or dredging work. Therefore, the accumulation of the quantitative data is required to support that check-dam has functions for both restraining and controlling sediment discharge. This would be a way to develop our erosion control technology to the scientific technology equipped with a more objective and systematic aspects.

• Korean Journal of Environmental Biology
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• v.24 no.2 s.62
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• pp.172-178
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• 2006

The dynamics of bacterial populations belonging to $\alpha\;\beta\;\gamma-subclass$ proteobacteria, Cytophaga-Flavobacterium (CF) group and sulfate reducing bacteria (SRB) in water column of the middle reaches of Nakdong River depending on sediment harvesting were analyzed by fluorescent in situ hybridization (FISH) at sediment harvesting site (near the Seongju bridge) and non-sediment harvesting site (near the Gumi bridge). In addition, some physico-chemical parameters such as temperature, pH, $chi-\alpha$ and electrical conductivity were measured. Regarding the number of total cell counts, cells stained by DAPI, there were no substantial quantitative differences between both sites, but those fluctuation at sediment Harvesting site was greater. And also the ratios of CFgroup and SRB to total cell counts tend to increase at sediment harvesting site with higher $chl-\alpha$, maybe due to the resuspension of sediment into water column. But the total proportion of all determined bacterial populations to total cell counts were greater at non-sediment harvesting site, compared with those at sediment harvesting site. Since the detectibility of bacteria by FISH depends on their metabolic activity, those lower proportion at the sediment harvesting site implies that sediment harvesting may lead to malfunction of those bacteria respect to nutrient recycling and subsequently negative effects on microbial food web.

• Clinical and Experimental Pediatrics
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• v.49 no.11
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• pp.1202-1210
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• 2006

Purpose : A quantitative and easily measured Doppler index of combined systolic and diastolic ventricular myocardial performance (Tei index) was recently proposed as a potentially useful predictor of global myocardial performance. However, presence of heart rate fluctuation makes it unreliable. Therefore, the modified Tei index was introduced by using tissue Doppler imaging (TDI) which enables measuring contraction and relaxation velocities from myocardium simultaneously. The purpose of this study was to investigate the effectiveness of the modified Tei index in the evaluation of global cardiac function. Methods : Forty eight patients in the acute phase of Kawasaki disease (KD) were studied. These patients were divided into two groups according to the modified Tei index. TDI and conventional echocardiography were performed. Systolic velocity, systolic displacement, E' velocity, E' displacement, A' velocity and A' displacement were measured at the base, mid-septum and the apex of the interventricular septum. Ejection fraction (EF), Tei index and modified Tei index were estimated. Results : Modified Tei index correlated negatively with systolic displacement, E' displacement and A' displacement at the base. Modified Tei index correlated positively with ESR and CRP. EF and Tei index were normal in KD patients. Conclusion : Modified Tei index is a safe, feasible and sensitive index for evaluating global ventricular functions in spite of normal EF and Tei index in KD.

• Journal of the Korean earth science society
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• v.22 no.1
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• pp.40-46
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• 2001

Heat exchange between the atmosphere and sea is produced using the data from two 3m discus buoy installed by KMA in 1996. The meteorological and oceanic characteristics at the Dukjukdo and Chilbaldo buoy for the period 1996 ${\sim}$ 2000 are discussed. Daily averaged sensible heat and latent heat flux at each site are estimated from bulk aerodynamic method using given data and analyzed. Quantitative analyses show SST indicates 1-year cycle like air temperature but has 1 month lag. Sea level pressure is lowest in July, humidity is higher from May to August, and wind speed has averaged value of 5 m/s and higher in autumn and winter. Sensible heat flux analyses present that strong heat loss from the sea occurs in autumn and winter and weak heat loss from atmosphere appears in spring and summer, and net sensible heat loss from the sea is found throughout the year. The ocean significantly releases latent heat into atmosphere from August to May but get a little latent heat from atmosphere in other months. Net latent heat loss from the sea is larger than net sensible heat loss except in January and February. Comparison with two sites suggests that the magnitude of heat flux and their fluctuation are generally stronger at Dukjukdo than at Chilbaldo. In case study, both sensible and latent heat flux is a little more at Chilbaldo in March 1998, but substantially stronger at Dukjukdo in November 1996.